Validation of the 3-oz water swallow test for aspiration following stroke. A 3-oz water swallow test identified 80% (16/20) of patients aspirating during a subsequent videofluoroscopic modified barium swallow examination (sensitivity, 76%; specificity, 59%). It also identified patients with more severe dysphagia aspirating larger amounts (sensitivity, 94%; specificity, 26%) or thicker consistencies (sensitivity, 94%; specificity, 30%) of test material. The 3-oz water swallow test is a sensitive screening tool for identifying patients at risk for clinically significant aspiration who need referral for more definitive modified barium swallow evaluation.


Cerebral glucose metabolism in Parkinson's disease with and without dementia. Although cognitive impairment is commonly associated with Parkinson's disease, the relative importance of cortical and subcortical pathologic changes to the development of dementia is controversial. Characteristic abnormalities in cortical glucose metabolism have been reported previously in Alzheimer's disease, a disease in which cortical changes predominate. We measured cerebral glucose metabolism with positron emission tomography in 20 control subjects and in 14 patients with PD with mental status ranging from normal to severely demented to determine whether changes in cortical glucose metabolism occur in early PD and whether the degree and pattern of metabolic change relate to the severity of dementia. The patients were divided into demented and nondemented groups according to the results of neuropsychological assessment. Age-adjusted covariance analyses were performed, since the age distribution varied between groups. The nondemented patients with PD showed widespread cortical glucose hypometabolism without any selective temporoparietal defects. The pattern of glucose hypometabolism seen in the demented patients with PD resembled that described in patients with Alzheimer's disease; ie, there was a global decrease in glucose metabolism, with more severe abnormalities observed in the temporoparietal regions.


Elevated neopterin levels in Guillain-Barré syndrome. Further evidence of immune activation. Neopterin is a by-product of guanosine triphosphate metabolism and is produced by macrophages in response to lymphocytic activation. We have studied serum neopterin levels in patients with Guillain-Barré syndrome to obtain further evidence of immune activation in this disease. Serum neopterin levels were significantly elevated in patients with Guillain-Barré syndrome compared with patients with other peripheral neuropathies and multiple sclerosis and with healthy control subjects. Serial analysis demonstrated that as neopterin levels fell, the clinical status of the patients with Guillain-Barré syndrome improved and soluble interleukin 2 receptor levels dropped. Thus, lymphocytic and macrophage activation may play a role in the pathogenesis of Guillain-Barré syndrome.


Frontal lobe dysfunction in unilateral lenticulostriate infarcts. Prominent role of cortical lesions. Most studies on frontal lobe dysfunction (FLD) in patients with striatal lesions did not consider possible associated cortical lesions not seen on computed tomographic scans. To determine the possible role of such cortical lesions, we assessed FLD in 10 patients with unilateral lenticulostriate infarct on computed tomographic scans. Magnetic resonance imaging revealed an associated cortical infarct not seen on computed tomographic scans in four patients. Using a battery of neuropsychological tests sensitive to FLD, we found that (1) the crossed tapping test was the only FLD test significantly disturbed in patients with pure unilateral lenticulostriate infarcts, (2) FLD was only present in patients with associated cortical infarct, and (3) caudate lesions only account for the number of echopraxic errors in the crossed tapping test. We conclude that unilateral isolated lenticulostriate infarcts might not lead to FLD, even though they may disturb the development of strategies involved in motor procedural learning.


Suicide and patients with neurologic diseases. Methodologic problems. The suicide risk in patients with many neurologic diseases has been reported to be greater than that in the general population. Studies on the subject are, however, often encumbered with methodologic problems. We appraised these problems and, based on an evaluation, reappraised knowledge of the suicide risk in patients with specific neurologic diseases. Using the computerized database MEDLINE, we identified all published reports with the key words suicide, attempted suicide, and neurologic diseases. We assessed and reviewed studies concerning the most common neurologic diseases for methodologic problems in the study design. The following methodologic problems emerged during our review: (1) choice of study type, ie, autopsy study or follow-up study; (2) choice of study population; (3) choice of control groups; (4) epidemiologic/statistical methods used; and (5) validity of statistics reported. We analyzed the methodologic problems in studies of patients with multiple sclerosis, epilepsy, Huntington's chorea, spinal cord lesions, cranial trauma, brain tumors, Parkinson's disease, vascular disorders, and migraine. In most of the studies, the methods used gave rise to uncertainty about the conclusion presented. An increased suicide risk was found in patients suffering from multiple sclerosis and spinal cord lesions as well as in selected groups of patients with epilepsy. In other neurologic diseases, the suicide risk may be increased, but the results are uncertain due to the methodologic problems in the study design.


Effect of ethanol on mouse brain microsomal phospholipid turnover. In an investigation of the effects of chronic and acute ethanol administration on phospholipid synthesis, mice subjected to chronic or acute ethanol administration were intraventricularly injected with 1,332 kBq of 2-3H-glycerol (3H-glycerol) and 4,070 kBq of 32P-phosphoric acid 15 min after the ethanol injection. One hour later, mice were sacrificed, and brain microsomes were prepared for analysis of incorporation of radioactivity into phospholipids. Chronic ethanol treatment significantly decreased incorporation of 3H-glycerol and 32P-phosphoric acid into phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol plus phosphatidylserine. However, acute ethanol treatment had no marked effect on incorporation of 3H-glycerol or 32P-phosphoric acid into any of these phospholipids. On the other hand, chronic ethanol administration had no significant effect on incorporation of the radioisotopes into triphosphoinositide (TPI) or diphosphoinositide (DPI) in microsomal fractions, or the 3H- and 32P-TPI/DPI ratios. However, acute ethanol administration decreased the incorporation of 3H-glycerol into DPI and TPI, but did not change the TPI/DPI ratio; it also significantly increased the 32P-TPI/DPI ratio and decreased 32P-phosphoric acid incorporation into DPI but did not significantly affect 32P-phosphoric acid incorporation into TPI. Chronic ethanol administration is thought to have altered the turnover of phospholipids in the microsomal membrane, thereby affecting both the levels and turnover of neurotransmitters. In addition, the change of labeled TPI/DPI ratio observed after acute ethanol treatment may reflect nicotinic receptor activity in the mouse brain.


Effect of acetaldehyde on ethanol absorption in the canine jejunum. The effects of acetaldehyde on ethanol absorption from the intestinal tract were studied using canine jejunal segment. A thirty-centimeter jejunal segment with intact vascular supply was isolated, and jejunal absorption studies were performed by administering a 17% ethanol solution (0.4 g/kg) into the lumen of the jejunal segment. In the control group, blood ethanol concentrations in the portal vein increased rapidly, with a peak level of 9.8 +/- 1.9 mM 30 min after administration. In the cyanamide-pretreated group, dogs were injected intravenously with cyanamide (100 mg/kg), an inhibitor of acetaldehyde dehydrogenase, 150 min before ethanol dosing. The blood ethanol concentration in the portal vein of this group, accompanied by a high acetaldehyde concentration, increased gradually, reaching a peak of 10.7 +/- 1.84 mM 120 min after ethanol administration. Each concentration gradient corresponded to the systemic circulatory order from the portal vein for ethanol concentration, and from the hepatic vein for acetaldehyde concentration. The absorbed amount of ethanol in the control and cyanamide-pretreated groups was 94.9 +/- 4.1% and 69.3 +/- 4.8%, respectively. Pharmacokinetic analysis indicated that a presence of high acetaldehyde concentration in the blood resulted in less ethanol reaching the systemic circulation (control: 7.34 +/- 2.95 h-1, cyanamide-pretreated: 1.08 +/- 0.75 h-1). The results also suggest that the absorption of ethanol from the intestine decreases when there is a high acetaldehyde concentration in the blood.


Ethanol enhances, but diazepam and pentobarbital reduce the ambulation-increasing effect of caffeine in mice. The interactions of caffeine (10 mg/kg p. o.) with various doses of ethanol, diazepam or pentobarbital were investigated by observing the ambulatory activity of mice. The ambulatory activities after the coadministration of caffeine with ethanol (1.6, 2.4 and 3.2 g/kg p. o.) were significantly higher than those after the single administration of the corresponding doses of individual drugs. Ethanol alone significantly increased the activity with ataxia at 2.4 and 3.2 g/kg, suggesting that 1.6 g/kg of ethanol was an optimum dose for studying the interaction of caffeine with ethanol. Although diazepam (0.25, 0.5 and 2 mg/kg s. c.) and pentobarbital (1, 3 and 10 mg/kg s. c.) alone did not change the activity, they significantly reduced the effect of caffeine. Naloxone (1 and 5 mg/kg s. c.) did not modify the effect of caffeine alone, but, at 5 mg/kg, it was effective in significantly reducing the ambulation-increasing effect of caffeine with ethanol (1.6 g/kg) to nearly the level of caffeine alone. Ca-cyanamide (5 mg/kg p. o., pretreatment 30 min before), reserpine (1 mg/kg s. c., pretreatment 4 hr before) and alpha-methyl-p-tyrosine (200 mg/kg i. p., pretreatment 1 hr before) reduced the ambulation increment induced by caffeine alone or combination of caffeine with ethanol. Ethanol, diazepam and pentobarbital are classified as CNS depressants, and caffeine as a CNS stimulant. However, the present experiment demonstrated that the interaction of caffeine with ethanol was very different from that of caffeine with diazepam or pentobarbital. In the enhancing interaction of caffeine and ethanol, both dopaminergic and endogenous opioid systems may be involved.


Patterns of alcohol abuse from the viewpoint of multiple substance abuse. 1. As a result of examining the alcoholism of 172 subjects, from the view point of multiple abuse in a long-term process, we were able to classify alcoholism into three patterns: Pattern I is the alcohol alone type, Pattern II is the alcoholism with legal drugs, such as hypnotics and tranquilizers and Pattern III is the alcoholism with illicit drugs, such as organic solvents and methamphetamine. 2. We ascertained the alcohol alone abuse type (Pattern I) existed. 3. Pattern II resembles Pattern I in living status, delinquency, experience of criminal acts and characters except that the abusers in Pattern II were younger than those in Pattern I. 4. The abusers in Pattern III showed a trend to incline to multiple abuse. They had antisocial characters and family problems and the level of their social life was disrupted from their youth in many cases.


[Alcohol drinking behavior based on the neurochemical background. I. Alcohol preference and brain monoamines]. The relationship between voluntary alcohol consumption and monoamine levels was studied in the inbred strains of C57BL/6N, C57BL/6J, A/J, BALB/cA, CBA/N, C3H/He and DBA/2Cr mice; the congenic mouse strain B10. Br/Sg, and the senescence accelerated mouse (SAM P1, SAM P2). C57BL strains exhibited a high alcohol preference whereas the other strains exhibited a low alcohol preference. A clear positive relationship was found between alcohol intake (g/kg/day) and brain norepinephrine (NE) level (r = 0.683, p < 0.05), and a clear negative relationship between alcohol intake and brain serotonin (5HT) level (r = -0.628, p < 0.05). These results suggest that a voluntary alcohol intake in mice is genetically influenced with the brain monoamines, and depend upon the levels of brain NE and 5HT.


[Alcohol drinking behavior based on the neurochemical background. II. Alcohol preference and aging]. The present studies have investigated the relationship between alcohol behavior and aging in several strains of mice. First experiments have carried out whether a free choice of 10% (v/v) ethanol and tap water for 4 weeks changes the alcohol preference and the brain neurotransmitters in three inbred strains of mice, C57BL/6J, C3H/He and DBA/2Cr. Mice of these strains showed mean ethanol intakes of 4.41, 1.76 and 0.77 g/kg/day, respectively. Levels of the brain monoamines did not change in the alcohol preferring C57BL/6J mice, but in those with less preference of alcohol, C3H/He and DBA/2Cr, there were significant increases in dopamine and 5HT levels during the four weeks experiment. Second studies have reexamined if the factor of aging affects on the alcohol preference or drinking behavior in mice. Intake of 10% ethanol (ml/day) and alcohol preference (%) increased significantly with age. A further study was conducted in which groups of 16 week old mice were checked for alcohol preference along with a completely naive control group. The alcohol preference and alcohol intake were maximum in mice given free access to ethanol at 4 weeks of age. These results suggest that a) the mouse strain with a low preference of alcohol undergo neurochemical changes after exposure to 10% ethanol and water even be free choice, and b) alcohol drinking behaviors are not only affected on the general aspects but also the factor of aging and the conditions in which mice have expressed the accesses to alcohol.


[Lymphocyte adenylate cyclase activity in alcoholics]. Lymphocyte adenylate cyclase (AC) activity in alcoholics was examined. Gpp(NH)p-stimulated AC activity was not altered in lymphocyte membranes from alcoholics in acute withdrawal state. In the case of long-term abstinent alcoholics, who maintained abstinence from alcohol for at least one year, lymphocyte Gpp(NH)p-stimulated AC activity was slightly reduced but not significantly. However, the extent of AC activity induced by 250 mM ethanol in vitro, in the presence of Gpp(NH)p, was significantly reduced in lymphocyte membrane from long-term abstinent alcoholics. These results indicate that lymphocyte AC activity is a biological marker for alcoholics.


Review of obstetric operative intervention rates. The trends in obstetric operative intervention at a major teaching hospital in Sydney, Australia, were reviewed during the decade 1979-1989. While the caesarean section rate has increased by 36.4%, forceps deliveries have decreased. The normal delivery rate has remained constant at 67%.


Umbilical artery blood flow in intra-uterine growth retarded fetuses and fetal outcome: a study of 102 cases. The 102 fetuses diagnosed by ultrasound to be asymmetrically growth-retarded had blood flow velocity waveforms of the umbilical artery studied. Sixty-two cases had normal blood flow, 28 had abnormal blood flow but with present end-diastolic flow, 8 had absent end-diastolic flow, and 4 had reversal of end-diastolic flow. Comparison was made between the blood flow status and other biophysical methods of antenatal surveillance and perinatal outcome. There is a strong correlation between abnormal blood flow and abnormalities detected by other biophysical methods of antenatal surveillance. Our study shows that fetuses with severe blood flow impairment tend to be more severely growth-retarded and to be delivered earlier. Our results also show abnormal blood flow to be associated with a poor perinatal outcome. Those fetuses with severe impairment of blood flow suffered a high incidence of operative delivery for fetal distress, acidosis at birth, perinatal mortality and morbidity. The association between abnormal blood flow and the 5-minute Apgar score is significant only in those with the severest impairment of blood flow. Our results are in close agreement with similar studies recorded in the literature.


Tetanic uterine contraction may be a cause of persistent fetal bradycardia after fetal blood sampling by ultrasound-guided cordocentesis. Persistent fetal bradycardia necessiating emergency cesarean section is uncommon but a serious complication of ultrasound-guided cordocentesis. The cause of this complication, however, is not completely known. Reported here is a case of tetanic uterine contraction after fetal blood sampling via cordocentesis.


Evaluation of measurement of fetal crown-rump length from ultrasonically timed ovulation and fertilization in vitro. To assess with accuracy the development and maturity of the fetus, we evaluated fetal growth in 46 pregnant women who had conceived subsequent to ultrasonically timed ovulation. Fetal crown-rump length (CRL) was measured at gestational ages that differed by about 1 day from those previously reported. The variance in CRL measurements at each gestational age was small, and the data were normally distributed. The CRL growth curves of this and previous studies were tested using measurements from 7 pregnancies derived from in vitro fertilization (IVF). The data from IVF pregnancies were consistent with our curve, having 1 day difference to those previously reported. The gender of the fetus did not influence the CRL during the first trimester. The results suggest that fetal growth is uniform during the first trimester.


Severe ovarian hyperstimulation syndrome with minimal ovarian enlargement: a case report. Severe ovarian hyperstimulation syndrome is an uncommon but potentially lethal complication of treatment with in vitro fertilization and other assisted reproductive technologies. We describe such a case which was atypical in that ascites and hydrothorax occurred despite the absence of ovarian enlargement. Whilst the pathophysiology of the syndrome remains unclear, the clinician must remain alert to the possibility of such an unusual presentation of this syndrome.


Assessment of follicular maturity by follicular diameter and fluid volume in a program of in vitro fertilization and embryo transfer. We compared the assessment of follicular maturity by follicular diameter or follicular fluid (FF) volume and the subsequent fertilization and cleavage of the oocytes in 36 patients who had ovarian stimulation performed for in vitro fertilization and embryo transfer (IVF-ET). All patients received clomiphene citrate and human menopausal gonadotropin. The daily growth of follicles was assessed ultrasonically for 6 consecutive days before oocyte collection. The follicular diameter was found to be well correlated with the volume of follicular fluid. There were no significant differences among the dominant, second, and third follicles in the rates of oocyte recovery, maturation, fertilization, or cleavage. The rates of oocyte maturation and fertilization in FF volumes of 5.1 to 7.0 ml were significantly higher than in volumes of 1.1 to 5.0 ml, but the cleavage rates were similar. A smaller percentage of embryos developed to the four-cell stage when the oocytes were recovered from follicles with volumes of 1.1 to 3.0 ml. These observations suggest that follicular volume is a good parameter for judging the maturity of oocytes. It is also suggested that, although the oocytes of small follicles can be fertilized and cleaved, oocytes from larger follicles may have a better developmental capacity.


Vulvar dystrophy: a clinical follow-up.

Vulvar dystrophy: a clinical follow-up. The vulvar dystrophy is an enigma and one of the most controversial topic as for the pathogenesis, clinical outcome and particularly the malignant potentiality. There has been very few systematic studies regarding vulvar dystrophy in Japan. Vulvar dystrophy with dysplasia is said to be a pre-malignant condition of the vulva. So in our institute a prospective follow-up of 5 months to 4 years was obtained in vulvar dystrophic patients after a conservative protocol of treatment. The initial histological diagnosis revealed 17 patients with squamous hyperplasia (9 patients with dysplasia and 8, without dysplasia), lichen sclerosus in 5 and other dermatoses in 1 patient. "Itching" was the most frequent complaint, encountered in 20 (69%) of the study patient. Amongst these patients 4/5 of lichen sclerosus and 16/18 of squamous hyperplasia and other dermatoses had complete symptomatic relief with testosterone and corticosteroid respectively. Morphologically 22/23 (96%) had more than 50% decrease of the total lesion. In squamous hyperplasia with dysplasia after treatment, the re-biopsy revealed improvement of the dysplasia in all the cases with total disappearance in the mild dysplasia group. So far, vulvar carcinoma did not develop in any of the patient followed in our study who received treatment for vulvar dystrophy. So, for vulvar dystrophy, a benign squamous epithelial disorder of the vulva, steroid hormone therapy is indeed a logical and a consistent one.


Association between chlamydial infections and pelvic lesions. Chlamydia trachomatis usually causes asymptomatic cervicitis, but it sometimes ascends into the uterine cavity, fallopian tubes, or peritoneal cavity, causing pelvic inflammatory disease and infertility. In this study, we examined endocervical chlamydial antigens and serum chlamydial antibodies in infertile women and laparoscopically evaluated pelvic lesions according to our pelvic scoring system. In patients testing positive for a chlamydial infection, the total pelvic score was significantly higher than in patients testing negative. When each area examined was assessed separately, however, only the tubal score was significantly higher in the chlamydia infected patients. These findings may indicate that tubal lesions are the major cause of infertility in women with chlamydial infections.


Immunohistochemical and ultrastructural investigation of new membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) in gynecologic neoplasms. New membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) were investigated immunohistochemically by avidin-biotin immunoperoxidase technique and immunoelectron microscopy in various gynecologic neoplasms and normal gynecologic tissues. MP2 A and MP2 B were not specific for malignant tumors. MP2 C was present in 67-100% of ovarian carcinomas, 100% of benign dermoid cysts, and 77% of endometrial carcinomas. Except for endocervical adenocarcinomas, MP2 D was hardly detectable in gynecologic malignancies. Although MP2 E was hardly detectable in benign gynecologic tumors, this protein was present in ovarian carcinomas, uterine squamous carcinomas, endocervical adenocarcinomas, and endometrial adenocarcinomas. These results suggest a possible clinical application of these MP2 proteins as a new tumor marker for gynecologic malignancies.


Vascular wall arachidonic acid metabolism and fetal growth in the pregnant STZ-induced diabetic rat. In pregnant women with severe diabetes mellitus, intrauterine growth retardation (IUGR) may occur despite hyperglycemia. Uterine blood flow may be an important factor in this process. Using pregnant streptozotocin-induced diabetic rats (pregnant STZ-diabetic rats), we evaluated functional and morphological changes in the endothelium, as well as platelet thromboxane A2 (TXA) production and their influence on uterine blood flow. Decreased basal endothelial prostacyclin (PGI2) production as well as significant attenuation of the production response to stimulus was noted, suggesting an impairment of PGI2 production. In the platelet, TXA2 production was augmented, leading to a hypercoagulable state. Decreased myometrial blood flow was documented. Scanning electron microscopy (SEM) revealed definite morphological abnormality of the endothelial cells, probably affecting the permeability to molecules, a major endothelial function. Based on these data, the endothelial derangements suggested by SEM and arachidonic acid metabolism alterations may affect fetal growth in the severe pregnant diabetic through alterations in uterine blood flow.


The adverse effects of l-methamphetamine on the development of explanted rat embryos. The adverse effects of l-methamphetamine on the development of rat embryos were studied by means of a whole culture system. The embryos explanted at 12.5th days of gestational age were cultured for a total of 24 hours. After pre-culturing for 6 hours, 4 groups of embryos received additional culturing for 18 hours with saline or various concentrations of l-methamphetamine; 0.5, 2.0 and 5.0 mumol/dl. There was no significant difference in the survival rate among 4 groups. The groups over 2.0 mumol/dl of l-methamphetamine showed significant reduction of crown-rump length, somite number, protein content, DNA content, and protein/DNA ratio. It is suggested that over 2.0 mumol/dl of l-methamphetamine reduces the development but not the survival of rat embryos under whole culture system.


Amplification of nocturnal melatonin secretion in women with nocturnal hyperprolactinemia. In order to assess the pathophysiological role of melatonin (MLT) in nocturnal hyperprolactinemia (NH), nocturnal serum MLT and prolactin (PRL) levels were measured in samples collected every 2h over a 12-hour period (2000h-0800h) from 5 normal women and 9 women with NH under physiological light/dark condition (lights off from 2100h to 0600h). Furthermore, differences in the PRL response to acute oral administration of MLT (1 mg or 5 mg) during the daytime between the 2 groups was studied. Nocturnal MLT levels in patients with NH were significantly higher (p < 0.02) than in normal women. The maximal PRL levels (52.6 +/- 26.7 ng/ml at 2400h) during the night in patients with NH were significantly higher (p < 0.05) and were reached 4h earlier than in normal women. The response to administration of 1 mg of MLT was not different between the 2 groups. However, administration of 5 mg of MLT to normal women resulted in a rapid and prominent PRL release, similar to that observed at nighttime in patients with NH. These results indicate that the abnormal PRL release in patients with NH is not due to higher sensitivity to MLT. However, the elevated MLT levels in patients with NH may be related to the neuroendocrine disorder.


Effects of cochlear impairment and equivalent-threshold masking on psychoacoustic tuning curves. Psychoacoustic tuning curves in simultaneous masking were measured in three groups: listeners with hearing impairment of primarily cochlear origin, normal listeners with equivalent-threshold masking (ETM) and normal listeners tested in the quiet. ETM was produced by presenting a continuous back-ground noise that was spectrally shaped to yield masked thresholds within 3 dB of each impaired listener's quiet thresholds. For the tuning curves, the level of a 50-Hz-wide noise band necessary to mask a 10-dB SL tone was measured for six masker frequencies. Results under ETM indicate that the shape of the tuning curve depends not only on masked threshold at the probe frequency but also on the spectral shape of the masker. Tuning curves are abnormally broad in some impaired listeners even when the effects of their elevated thresholds, audiometric configuration and altered intensity perception are taken into account by comparisons with normal listeners with ETM.


Low-frequency specificity of the auditory brainstem response threshold elicited by clicks masked with 1590-Hz high-pass noise in subjects with sloping cochlear hearing losses. In this study, the frequency specificity of the ABR threshold to stimulation with a click masked with 1590-Hz high-pass noise was determined in subjects with sloping cochlear hearing losses both high- and low-frequency in character. The results show that the ABR threshold elicited by this stimulus is low-frequency specific. The standard error in estimating the 1,000-Hz pure-tone threshold from the high-pass-noise-masked click-evoked ABR threshold is 10.2 dB which equals that for estimating the 3,000-Hz pure-tone threshold from the routinely used unmasked click ABR threshold. The ABR threshold elicited by a click masked with 1590-Hz high-pass noise can therefore be regarded as an accurate tool to predict the pure-tone hearing loss at 1,000 Hz. However, this method is less suitable for routine clinical testing because of the masking noise needed: the occasional high loudness level adversely affects the response quality and reduces the dynamic range of pure-tone hearing losses to be assessed. A third disadvantage is that determining the masking level electrophysiologically for each ear is time consuming. The search for a method with no or less masking noise should therefore continue.


Comparison between the frequency specificities of auditory brainstem response thresholds to clicks with and without high-pass masking noise. In this study, the frequency specificity of the auditory brainstem response (ABR) threshold to a click masked with 1590-Hz high-pass masking noise is compared with the frequency specificity of the unmasked click-evoked ABR threshold. The ABR threshold to the high-pass-noise-masked click stimulus is low frequency specific and corresponds with the 1,000-Hz pure-tone threshold. Although the ABR threshold to the unmasked click stimulus corresponds with the '3,000'-Hz pure-tone threshold, the frequency specificity seems much less pronounced than that of the low-frequency-specific stimulus. This study shows, however, that this apparent lack of frequency specificity can be attributed to the selection of pure-tone hearing losses. The ABR threshold evoked by an unmasked click stimulus is, therefore, preeminently useful as a high-frequency point of a two-point audiogram. The possible reasons why the ABR threshold evoked by a broad-band stimulus as the unmasked click corresponds with the higher frequencies of the pure-tone audiogram are discussed.


Carboplatin and cisplatin ototoxicity in guinea pigs. Ototoxic effects of cisplatin (1.5 mg/kg), cisplatin with mannitol (1.5 mg/kg cisplatin with 15 mg/kg mannitol) and carboplatin (6 mg/kg) were compared in guinea pigs treated 5 days a week for 5 consecutive weeks. Auditory thresholds were measured in awake animals by means of the compound action potential recorded from electrodes implanted near the round window. The endocochlear potential (EP) was measured in the first turn through the round window, and hair cell counts were estimated by the surface specimen technique. The most pronounced ototoxicity (threshold shifts and hair cell loss) was observed with pure cisplatin. Cisplatin with mannitol appeared to be less toxic than pure cisplatin, and carboplatin the least toxic. Even carboplatin produced significant threshold shifts, particularly at high frequencies, but they were not accompanied by hair cell loss. Values of EP were not different from those in normal control animals.


Digital echocardiography in myocardial infarction. Probably the most under-utilised application of echocardiography is in patients with coronary artery disease (CAD). This under-utilisation is striking since echocardiography can be very valuable in evaluating the natural history and therapy of CAD. One reason why echocardiography is not being utilised to its fullest is because of the reliance on videotape to record and display echocardiograms. This medium is time consuming and inconvenient for clinicians to review studies, it is not ideal for detecting subtle wall motion abnormalities, and videotape is impractical for comparing serial studies. Recording and storing echocardiograms on a digital medium overcomes these difficulties. Digital cine loops of single cardiac cycles provide great versatility. Multiple views or studies can be displayed simultaneously, subtle changes in wall motion are more easily detected and different views, or serial studies, can be readily compared. Such images can be displayed on computers on the ward or in the coronary care unit (CCU) and be available 24 hours a day, seven days a week at the convenience of the clinician. One does not need to find a recording on a two hour videotape, which may be in the ultrasound instrument, and one can view the exam in 30 sec instead of 5 to 10 min. Regional and global left ventricular function is one of the most important manifestations of CAD. With new therapeutic efforts at restoring myocardial function and limiting infarct expansion, assessing LV function is more important than ever. Digital echocardiography is an extremely practical and convenient way for clinicians to obtain this information.


Transoesophageal echocardiography in heart disease--old technologies, new tricks. Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, 'new tricks' in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection. TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.


Left ventricular energy in mitral regurgitation: a preliminary report. Energy exchange based on Newtonian principles is the most appropriate way to express the function of any pump--including the heart. Using information obtained at cardiac catheterisation, we have measured the total work energy (ET) of the left ventricle (LV) (mean 1.63 F) in patients with severe mitral regurgitation (mean regurgitant fraction 0.66). ET was approximately 84% above normal. Of the regurgitant energy (RE) (mean 0.95 F), on average , 3/4 (73.6%) was kinetic (KE) and 1/4 (23.4%) potential (PE). Both components represent wasted LV energy: the kinetic energy associated with turbulence lost as heat, the potential energy responsible for a rise in Left Atrial (LA) pressure. The amount of PE as a percentage of total regurgitant energy (RE) varied considerably from one patient to another (10.5% to 54.4%). Hence, colour flow mapping which detects only KE of turbulent jet flow must underestimate LV energy loss and, because of patient to patient variation, cannot consistently reflect severity of regurgitation. Measurements of PE correlate well with wedge P-wave height. Corresponding non-invasive estimates were made using sphygmodynamometer-calibrated indirect carotid pulse tracings and echocardiographic measurements. These were not significantly different from the invasive measurements. Unfortunately, the calculation of PE is indirect and involves subtraction, so that measurements for individual patients were not accurate enough for clinical use. Part of the non-invasive calculation involved an estimate of left atrial pressure based on the blood pressure measurement and Doppler velocity of regurgitation; this should be a useful measurement in itself.(ABSTRACT TRUNCATED AT 250 WORDS)


Mitral valve billowing and prolapse--an overview. Three decades after it was demonstrated that nonejection systolic clicks and late systolic murmurs have a mitral valve origin and that a specific syndrome is associated with the primary degenerative mitral lesion, numerous questions remain unanswered. A principal cause of confusion is the use of the term 'prolapse', which essentially implies a pathological state, in many patients with minimal evidence of a mitral valve anomaly. It should be recognised that no specific feature, whether evaluated by high standard echocardiography or indeed by careful morphological and histological examination, can be defined which distinguishes a normal variant from a pathological valve. There is a gradation from the normal billowing during ventricular systole of mitral leaflet bodies to marked billowing. With advanced billowing or floppy leaflets, failure of leaflet edge apposition supervenes (true prolapse). This is functionally abnormal and allows mitral regurgitation. Prolapse in turn may progress to a flail leaflet and hence gross regurgitation. Relatively rare complications of this degenerative mitral valve anomaly include systemic emboli, infective endocarditis, arrhythmias and, arguably, autonomic nervous system abnormalities. An attempt is made to clarify the management of some symptoms and other aspects of mitral prolapse-including rheumatic anterior leaflet prolapse (without billowing) which remains prevalent in South Africa and Third World countries.


Echocardiography in the management of mitral valve prolapse. Echocardiography plays a major role in the management of patients with mitral valve prolapse (MVP). The technique has greatly enhanced our understanding of the pathophysiology, epidemiology and natural history. There are major and minor echocardiographic diagnostic criteria for prolapse. Major criteria involve the mitral leaflets and include late systolic posterior displacement on M-mode, bulging into the left atrium on 2D long-axis (LAX) view, and thickening and redundancy of the leaflets. Minor criteria include holosystolic posterior prolapse on M-mode, bowing of the mitral leaflets into the left atrium (LA) in the apical 2D views, and late systolic mitral regurgitation on the Doppler echogram. Any of the major criteria should be sufficient to make the diagnosis. One or two minor criteria without a major sign would be questionable. The degree of thickening and redundancy and the presence and quantitation of mitral regurgitation influence prognosis. Echocardiography is also helpful in identifying complications such as endocarditis and ruptured chordae. An echocardiogram may not be necessary for the diagnosis, but it is helpful for prognosis and as a baseline for possible future changes. The frequency of follow-up echocardiograms should be determined by clinical findings. When mitral regurgitation is present, then one should follow LA and left ventricular size and function. Transoesophageal echocardiography may be desirable for better definition of vegetations or flail leaflets and is frequently used to monitor surgical repair.


Genes, gender and geometry and the prolapsing mitral valve. Mitral Valve Prolapse (MVP) is usually a variant of normal occurring in about 4% of the population. Complications are relatively uncommon, but false associations due to ascertainment bias have had a potential for iatrogenic harm. Adverse outcomes which do occur in a subset of MVP subjects are considered here in relation to the contributions of genes, gender and geometry. There are definite associations between MVP and several dominantly inherited connective tissue abnormalities; it occurs in 85% of adults with Marfan syndrome. All these contribute to a very small proportion of the MVP population. A larger less easily characterised group with dominant inheritance and some features of a connective tissue disorder awaits DNA studies for identification. For most MVP subjects our data define significant family aggregation consistent with polygenic inheritance; the likelihood of a first degree relative having MVP is about two and a half times the population average. There is a higher prevalence in young women than in men-5% versus 3%; this has also been demonstrated for floppy mitral valve (MV) at autopsy. MVP complications of chordal rupture, severe mitral regurgitation and infective endocarditis are, however, two to three times more common in men, are age related and evident after the age of 50 years. Higher blood pressure in men may contribute to this in accordance with a response-to-injury hypothesis to explain progressive valve changes. Leaflet, annulus and left ventricular size differences and septal changes are geometric variants with a potential for increasing tension-related valve injury.(ABSTRACT TRUNCATED AT 250 WORDS)


Mitral valve palpitations.

Mitral valve palpitations. Few disorders ever provoked more interest and controversy than mitral valve prolapse (MVP). Past echocardiographic over-diagnosis led to it becoming a whipping boy for otherwise unexplained chest pain, palpitation, arrhythmias and emboli. Surgical centres reported a high incidence of endocarditis and severe regurgitation. Most investigators who have studied the prevalence of arrhythmias in MVP have concluded that they are more common in this syndrome than in the general population and that there is a causal rather than a fortuitous relationship. However, the prevalence of arrhythmias in reported studies is probably higher than in unselected MVP patients. Multiple ventricular premature beats, ventricular tachycardia and sudden death have been reported. Suggested mechanisms have included a focal cardiomyopathy with incoordinate contraction and relaxation, QRS dispersion, a long QT, traction on papillary muscles by prolapsed leaflets, interference with the blood supply of the papillary muscles, stimulation of the endocardium by the chordae and diastolic depolarisation of muscle fibres in redundant leaflets with triggered repetitive automaticity. MVP has been associated with pre-excitation giving rise to atrioventricular re-entry tachycardia. Autonomic dysfunction and a hyperadrenergic state has been claimed and this may also be responsible for supraventricular arrhythmias including atrioventricular nodal re-entry tachycardia, flutter and fibrillation. Electrophysiological studies have yielded contradictory results which may be due to the heterogeneity of the patients studied and variability of the mechanisms. Whatever the true prevalence, arrhythmias in MVP are usually benign. Syncope and sudden death are rare. Anti-arrhythmic therapy is only warranted in patients with frequent and distressing symptoms shown to be due to the arrhythmias or when arrhythmias are judged potentially life threatening.(ABSTRACT TRUNCATED AT 250 WORDS)


Optimising plasma lipids: public intervention versus high risk management. A public health strategy carries more constraints than a high risk strategy because it targets both low risk and high risk individuals; this requires cautious intervention and hence achieves only a modest reduction in risk. Nevertheless, a modest population-wide fall in the concentrations of atherogenic lipoproteins leads to substantial numbers of preventable heart attacks and deaths. Other strategic considerations are to lower non-lipid cardiovascular risks (hypertension, clotting tendency) and to prevent other diet-related disease (such as cancer) through interventions which lower plasma lipids. The major nutritional changes which achieve this are optimising energy balance, reducing total fats and saturated fatty acids and increasing plant foods which are rich sources of unsaturated fatty acids, fibre and antioxidants. Each of these contributes to optimising the low density lipoprotein (LDL) concentration. Antioxidants (vitamins C and E mainly) may inhibit LDL oxidation. The strategy for lowering plasma triglyceride, especially in the context of atherogenic lipoprotein phenotypes, is mainly through energy balance, reduced saturated fat and alcohol. Correcting overweight especially in those with abdominal obesity, may normalise raised plasma triglyceride, low high density lipoprotein (HDL), abnormal LDL and even glucose intolerance and hypertension, which may be associated. The scientific basis for the lipid optimising effects of the different nutrients will be discussed.


The Apo A, B, a of coronary risk: back to kindergarten. Approximately 1% of the population have a dominantly inherited lipid disorder predisposing to premature vascular disease. Apolipoproteins (Apo) B, and A1, the carrier proteins for the atherogenic low density lipoprotein (LDL) and the protective high density lipoprotein (HDL) cholesterol respectively are markers for these disorders, as is Apo(a), the unique carrier protein for lipoprotein(a). We assessed changes in these apolipoproteins during the first 12 years of life, aiming to detect young families with inherited dyslipidaemia and implement early prevention. Among 1032 consecutively born babies in whom levels were measured within their first week and at a mean age of 8.5 months, the Apo B/A1 ratio and Apo(a) both tracked closely (p < 0.01 and < 0.0001). High B/A1 ratios (> 95 percentile) identified two families with familial hypercholesterolaemia, and infants with high Apo B identified two families with hyperapolipoprotein B. Apo(a) levels increased twofold between the first week and 8.5 months and were highly correlated (r = 0.73, p < 0.0001). Levels at 8.5 months were not different from parental values and were closely correlated with them. We then assessed school children aged eight to 12 years. In a pilot study (n = 1400) we have established normal apolipoprotein values and distribution patterns and defined the 95th percentile for each. This study is continuing and parents of children with high levels are being recalled (with their children) for lipid measurements. Our findings indicate that our approach is feasible and has wide acceptance, and that measuring Apo B/A1 and Apo(a) in childhood identifies families at increased cardiovascular risk. We have yet to assess the efficacy of our family-based coronary prevention programme.


Cholesterol and coronary heart disease mortality. The epidemiological relation between increased levels of blood cholesterol and increased risk of future heart disease is clear, both within and between countries. These strong relationships have led to the adoption of consensus statements in most countries which recommend measures such as the reduction of dietary saturated fat/an increase in the polyunsaturated/saturated ratio and other dietary and sometimes drug methods to reduce serum cholesterol. There is controversy as to whether these measures should be targeted at individuals with high levels of cholesterol or whether there should be a public health approach to the whole population. The public and medical debate has become more heated since the data from intervention trials are conflicting. Taken overall the trials do appear to show reduction in risk of coronary which is stronger for non fatal, compared with fatal coronary events. Meta analysis suggests that increasing benefit accrues from larger reductions and also longer reductions in cholesterol by intervention. However, individual trials frequently show variable results and some, especially the recent 15 year follow up of a Finnish five year intervention (by diet, cholesterol lowering and blood pressure lowering drugs) was strikingly adverse-although the total number of events was not large. Total mortality is much harder to influence and the sum of the available trials is hopelessly inadequate in size to address these questions. As a result confusion abounds and is unlikely to be clarified by the present on going trials. The need for more data is clear. The pilot study for the Oxford Cholesterol Study will be presented as a prelude for a proposed main study in about 20,000 high risk individuals.


Lowering cholesterol: effects on trauma death, cancer death and total mortality. Randomised trials of cholesterol reduction (26 trials, 50,000 patients, net cholesterol reduction approximately 10%) have demonstrated a clear reduction in the incidence of coronary heart disease (CHD) after just a few years of treatment. Overall, the reduction in CHD death was only half as large as the reduction in non-fatal myocardial infarction (MI), although both were statistically significant (2P < 0.005). In these trials, 60% of all deaths were from CHD, and since treatment reduced these by about 10%, the expected reduction in total deaths was about 6%. This expected reduction falls within the 95% confidence interval of the observed effect of cholesterol reduction on total mortality in these trials. There were small excesses of deaths from cancer and deaths from trauma among patients allocated active treatment. However, in no single trial, nor in the trials collectively, were these increases statistically significant. Furthermore, the increases did not appear to be specific to any one agent nor were the increases consistent between trials of the same agent. These observations are consistent with the hypothesis that the small excesses of cancer and trauma deaths observed in the cholesterol reduction trials occurred by chance.


Trials and tribulations: the ISIS experience. The ISIS trials group has grown slowly over the last ten years and now includes about 1000 collaborating hospitals worldwide. The original stimulus came from the thesis of a research student, Salim Yusuf, a newly qualified Rhodes Scholar from India. Yusuf's thesis (begun in 1976) examined methods of measuring infarct size quantitatively and paved the way to a preliminary trial of i.v. atenolol in 477 patients in Manchester and Oxford. Richard Peto was consulted about the statistical aspects of a trial design and pointed out that most clinical trials at that time were hopelessly inadequate in size to have the power reliably to ascertain the value of moderate but medically worthwhile treatments in many common conditions. We thus developed much larger collaboration, which still continues to grow. Dr Rory Collins joined the Oxford Cardiac Department and the CTSU in 1981 and now is the coordinator of the ISIS trials, and co-director with Richard Peto of the CTSU. Simple trials answer the questions rapidly and effectively. The mechanics of the trial do not hinder patient entry by participating doctors and nurses. The trials are mainly funded by industry, with 'priming' grants from the British Heart Foundation. Once the protocol is agreed the funding companies have no further input. The trials are planned and supervised by an international steering committee. Sir Richard Doll chairs the data monitoring committees. A brief overview of the three completed trials will be given, together with some peeps behind the scenes.


The push, the pull and the periphery.

The push, the pull and the periphery. If the failing left ventricle could be given an effective push, other approaches to the treatment of heart failure would not be needed. We have inotropes only for short-term parenteral use. We have no safe inotrope for chronic oral use. The effect of digitalis is only feeble and the phosphodiesterase inhibitors seem to increase mortality from sudden death. Diuretics are dramatic for acute pulmonary oedema and the mainstay for chronic fluid retention but do not improve the pump and by reducing blood volume stimulate the renin angiotensin system to vasoconstriction, further fluid retention and hypokalaemia. Nitrates drop pre-load without reducing blood volume but tolerance is a problem and stroke volume does not increase. Reduction of afterload helps the failing ventricle to empty, the pull and output increases. The angiotensin converting enzyme inhibitors (ACEI) are now the cornerstone of heart failure treatment, reducing mortality in severe heart failure (CONSENSUS) and superior to standard vasodilator therapy (V-HeFT-2) at improving the survival of patients with mild to moderate heart failure. ACEI can reduce the incidence of ventricular ectopy and probably do this through improving left ventricular function, from decreasing sympathetic tone, reducing myocardial oxygen demand or increasing serum potassium but ACEI did not diminish the incidence of sudden death in the SOLVD trial despite reducing mortality. Disappointingly little improvement in exercise tolerance and persistence of chronic fatigue in heart failure concentrated attention on the periphery.(ABSTRACT TRUNCATED AT 250 WORDS)


Aspects of active rheumatic carditis.

Aspects of active rheumatic carditis. Fulminating active rheumatic carditis has been observed for over 3 decades in this environment with no recent alteration in either the incidence or the pattern of presentation. Patients are black, seldom older than 20 years and are usually in their early teens but may occasionally be as young as five years. Heart failure is prevalent but occurs only when a haemodynamically important left-sided valve lesion supervenes. Regurgitation is the predominant valve lesion and involves principally the mitral valve. Mitral annular dilatation is the initial pathology and predisposes to lengthening--or rupture--of chordae tendineae and prolapse of the anterior leaflet. The resultant cardiac work-overload apparently perpetuates the rheumatic activity. Heart failure, whether caused by or associated with active rheumatic carditis, makes surgical management of the valve lesion mandatory as a life-saving measure. Mitral valve repair, rather than replacement, is the surgical procedure of choice but is not always practicable when the rheumatic activity is fulminant, significant aortic regurgitation associated or the surgeon relatively inexperienced. Aggressive medical therapy for heart failure, which should include vasodilator drugs, provides temporary improvement only. Contrary to ongoing doctrine, treatment with steroid drugs is neither life-saving nor beneficial. Varying degrees of left ventricular dysfunction are encountered pre-operatively and may be a sequel of the severe regurgitant valve lesion rather than of a rheumatic 'myocardial factor'.


Remodelling of the heart after myocardial infarction. In the first few hours after the onset of coronary occlusion the infarct zone stretches due to myocyte slippage. Subsequently the noninfarct zone develops volume overload hypertrophy with series addition of new sarcomeres and fibre elongation. Dilatation is detrimental as it increases ventricular wall stress and oxygen demand, and re-entry of electrical impulses may be influenced by stretching of the ischaemic scar resulting in ventricular fibrillation. Left ventricular remodelling and dilatation is a progressive process which begins early and continues in the months after infarction. The major determinants of the extent of remodelling are infarct size and patency of the infarct-related artery. Late reperfusion may reverse initial infarct dilatation and decrease left ventricular volumes by inducing calcium-activated contracture of the actomyosin complex. Expansion may also be inhibited by acceleration of healing, splinting of the infarct zone by salvage of subepicardial cells, and blood in the coronary arteries and veins supporting the infarct zone. End-systolic volume is the strongest predictor of long-term prognosis after infarction. A number of therapies including thrombolysis, angiotensin-converting enzyme (ACE) inhibition and nitrates have been shown to decrease left ventricular dilatation. The optimal time for commencement, dose, duration and the effects of combinations of therapy are yet to be determined.


Exercise echocardiography.

Exercise echocardiography. Exercise testing is an indispensable component of clinical cardiology. Latent disease or the full extent of a problem may not be apparent on a resting examination. Some form of stress is frequently necessary, especially in patients with coronary disease, to appreciate whether a patient has stress-induced ischaemia as manifested by exercise-induced chest discomfort, a drop in blood pressure or electrocardiographic changes of ischaemia. Unfortunately as with every test ECG and clinical monitoring have limitations. Patients may have ischaemia without pain, ECG changes may be non-specific, a resting abnormal ECG has limited value, and the location and amount of ischaemic muscle is not directly assessed. Monitoring the echocardiogram adds significant additional information to routine stress testing. By visualising the myocardium in the exercising individual, it is possible to assess a fundamental manifestation of ischaemia, regional wall motion abnormalities. This information helps identify the vessels and the amount of muscle involved. In addition resting wall motion abnormalities may detect clinically silent infarction or hibernating myocardium. Direct visualisation of the exercising heart provides an improved understanding of a patient's cardiac status. The technique is particularly useful in evaluating revascularisation procedures. Advances in instrumentation have reduced or eliminated many of the technical difficulties with obtaining and interpreting exercise echocardiograms. This examination has become an extremely useful adjunct to routine stress testing.


Exercise testing? Not at all.

Exercise testing? Not at all. The traditional approach to the ambulatory patient with suspected or definite coronary disease is to evaluate the clinical features, to perform non-invasive tests for myocardial ischaemia, and to proceed, if necessary, to coronary angiography and coronary revascularisation. However, when the results of the exercise tests are discordant with the clinical classifications they are usually misleading as diagnostic tools. When the exercise test is used to assist prognostication, the information provided overlaps with that available to the clinician and only the presence of ST segment depression is an independent prognosticator. The amount of ST segment shift has been found to be an inferior prognosticator to the severity of disease seen on a coronary angiogram and the latter allows for appropriate decisions to be made regarding coronary angioplasty or bypass surgery. A more appropriate use of exercise testing is as a gate for coronary angiography if there is real doubt or the nature of the chest pain or as an aid in therapeutic decisions if the coronary angiography interpretation is difficult.


The importance of assessing time-course behaviour of abnormal ST/T changes after exercise. Routine stress electrocardiography has been criticised for yielding too many so-called 'false-positive' results because ST/T changes that develop during and after exercise are prevalent. Recent studies in our institution indicate, however, that the time-course behaviour patterns of these ST/T configurational 'abnormalities' after exercise are different from those reflecting myocardial ischaemia due to epicardial coronary artery disease (CAD). Time-course analysis increases the predictive value of exercise testing and has dramatically decreased the number of asymptomatic subjects or symptomatic patients at low risk of having CAD being subjected to coronary arteriography in our institution. Our method of assessing post-exercise time course patterns of abnormal ST/T are described in detail. Ischaemic ST/T abnormalities have late onset, early offset or early onset, late offset whereas those ST/T changes associated with normal epicardial coronary arteries have late onset, late offset or early onset, early offset post-exercise time course patterns.


Heart failure: to digitalise or not? The view against. Despite extensive clinical experience the role of digoxin is still not well defined. In patients with atrial fibrillation digoxin is beneficial for ventricular rate control. For patients in sinus rhythm and heart failure the situation is less clear. Digoxin has a narrow therapeutic:toxic ratio and concentrations are affected by a number of drugs. Also, digoxin has undesirable effects such as increasing peripheral resistance and myocardial demands, and causing arrhythmias. There is a paucity of data from well-designed trials. The trials that are available are generally small with limitations in design and these show variation in patient benefit. More convincing evidence is required showing that digoxin improves symptoms or exercise capacity. Furthermore, no trial has had sufficient power to evaluate mortality. Pooled analysis of the effects of other inotropic drugs shows an excess mortality and there is a possibility that digoxin may increase mortality after myocardial infarction (MI). Angiotensin-converting enzyme (ACE) inhibitors should be used first as they are safer, do not require blood level monitoring, modify progression of disease, relieve symptoms, improve exercise tolerance and reduce mortality. Caution should be exercised in using digoxin until large mortality trials are completed showing either benefit or harm. Until then digoxin should be considered a third-line therapy.


Prevention of sudden cardiac death: the ICD, or an electrical end-point with preceding opportunities for intervention? Sudden cardiac death (SCD) is usually due to monomorphic ventricular tachycardia and/or ventricular fibrillation. However, in the vast majority of patients these arrhythmias are associated with advanced structural disease. In our society, this is usually due to coronary artery disease (CAD). The implantable cardioverter--defibrillator is the logical approach to management in survivors of SCD. Its rational use must be guided by electrophysiology study. However, a realistic and cost-effective approach to the prevention of a first cardiac arrest must be multifaceted and take cognisance of other aspects including primary prevention. Limitation of the size of myocardial infarction (MI) is vital. Trials already suggests that effective thrombolysis may impinge long-term on arrhythmic end-points. Following infarction, ventricular arrhythmias and sudden death may also be decreased by aspirin, beta-blockers, and possibly angiotensin converting enzyme inhibitors and amiodarone. Many post-infarction studies employ a combined end-point of death and clinical arrhythmias. However, death is usually confined to those with an ejection fraction < 35%. In them, treatment of associated heart failure is often a consideration and if the ejection fraction < 15-20%, depending on donor availability, transplantation may even be the preferred therapeutic option to the cardioverter-defibrillator.


The automatic implantable defibrillator is the most realistic and cost-effective way of preventing sudden cardiac death. Judgement about cost-effectiveness of medical treatments depends upon the criteria used to define effectiveness. The most rational single criterion is the Quality Adjusted Life Year gained (QALY). Comparisons of cost-effectiveness of treatments may be made by comparing the dollar costs per QALY. Both the dollar and the QALY comparisons are subject to all errors of biological variable measurement and bias introduced by experimental design seen in other biological experiments. The proper methodology for comparison is the prospective randomised controlled clinical trial. Such trials using the automatic implantable defibrillator (AICD) as prophylaxis against sudden cardiac death (SCD) have not yet been performed. The major underlying cause of SCD is coronary artery disease with previous myocardial infarction (MI) and provocative tests for ventricular arrhythmias are the most powerful predictors of SCD in infarction survivors. AICD implantation carriers a mortality of about 2%, and survival after successful implantation is about 89% at one, and 84% at two years. By comparison, infarction survivors with left ventricular ejection fraction < 0.4 and inducible slow monomorphic ventricular tachycardia have a survival rate of 70% at one, and 54% at two years. Antiarrhythmic drugs have not proven effective. There is an urgent need to confirm the advantage of the AICD by proper randomised controlled trial.


Improved feed intake and body weight change in sheep treated with dexamethasone at entry into pens or feedlots. Treatment with the synthetic glucocorticoid dexamethasone sodium phosphate increased the feed intake of sheep within 24 h. A single treatment with the longer-acting compound dexamethasone trimethylacetate had a slower effect, but resulted in improved feed intake and enhanced body weight gain over a period of 7 to 14 days. Treatment was effective in sheep housed individually and in sheep penned in groups. The improvement in body weight gain disappeared 15 to 20 days after a single treatment, but in most studies treated sheep had less variability in weight change than untreated sheep at this time. A statistically significant increase in body weight gain was observed in 8 of 11 trials; in the other 3 trials, it appeared that the feed intake of the untreated sheep was already maximal. Wethers treated with dexamethasone trimethylacetate on arrival at an assembly point for live export arrived in the Middle East 23 days later with a lower mean weight loss, partly because fewer sheep lost a significant amount of weight.


Resistance to synthetic pyrethroid pour-on insecticides in strains of the sheep body louse Bovicola (Damalinia) ovis. Groups of sheep infested with strains of Bovicola (Damalinia) ovis were obtained from flocks either with a history of failure to control lice with synthetic pyrethroid (SP) pour-on insecticides, or from farms where SP compounds were not used. The sheep were treated according to the manufacturer's recommendations with registered "off-shears" SP formulations. All treatments were applied under ideal conditions with doses calculated on an individual body weight basis and applied to the dorsal mid-line from the base of the neck to the butt of the tail. Treated sheep were kept in pens and maintained in separate groups. The pour-on SP treatments significantly reduced the lice population but failed to eliminate the infestation in 7 of 13 experiments in sheep carrying strains of lice with resistance factors of greater than 4 to at least one of the SP compounds. Failures occurred with all three of the SP pour-ons currently registered for lice control in NSW and with both water-based and organic solvent-based formulations.


Production responses to internal parasite control in dairy cattle. A significant increase in milk production, averaging 164 litres per cow per lactation (a 4.8% increase), was seen after cows infected with gastrointestinal nematodes, paramphistomes and Fasciola hepatica were treated with broad-spectrum anthelmintics. Three hundred and ninety pairs of cows from eight herds with year-round calving were studied. One cow in each matched pair was given 7.5 mg/kg fenbendazole, 7.5 mg/kg levamisole hydrochloride and 15 mg/kg oxyclozanide in March, May and August of one year; the other cow in the pair received no anthelmintic. The number of nematode and trematode eggs was significantly decreased in the faeces of treated cows.


Respiratory mechanics of horses during stepwise treadmill exercise tests, and the effect of clenbuterol pretreatment on them. Normal Standardbred horses were given an incremental exercise test on a horizontal treadmill to evaluate the influence of exercise on gas exchange, resistance, dynamic compliance and inertance of the respiratory system. The exercise test consisted of 2 min exercise steps at each of the following speeds: 2.4 m/sec (walk), 4.5 m/sec (slow trot), 7.0 m/sec (fast trot) and 10 m/sec (gallop). At rest and after 1 min of exercise at each step, airflow, tidal volume, respiratory frequency, pharyngeal, mid-oesophageal and transdiaphragmatic pressures and arterial blood gas tensions were measured. The same horses were subsequently treated intravenously with clenbuterol (0.8 microgram/kg) and an identical exercise test and measurement performed 10 min after clenbuterol injection. In response to exercise, there were large increases in tidal volume, respiratory frequency, airflow and pressures. Exercise was associated with a decrease in upper airway resistance but total pulmonary resistance was unchanged. Exercise did not alter inertance or dynamic compliance, horses became hypoxaemic, and at 10 m/sec (galloping) also developed hypercarbia. Treatment with clenbuterol did not alter any of these measurements in response to exercise. These data suggest that dilation of upper airways occurs during exercise, and that inertial forces are important in strenuously exercising horses and may influence the accuracy of dynamic compliance determinations at high exercise intensities.


Isolation and characterization of two opioid peptides from a bovine hemoglobin peptic hydrolysate. Two opioid peptides were isolated from a bovine hemoglobin hydrolysate, by use of gel permeation (GP) and reverse phase (RP) high performance liquid chromatography (HPLC). Their primary structure and accurate molecular weights, determined by amino acid analysis and fast atom bombardment (FAB) mass spectrometry, were identical to fragments 31-40 (LVV-hemorphin-7) and 32-40 (VV-hemorphin 7) of the beta-chain of bovine hemoglobin. The same fragments occur in human hemoglobin in positions 32-41 and 33-41 of the beta-chain, respectively. The opioid potency of these peptides, exhibited by use of electrically stimulated muscle of isolated guinea-pig ileum (GPI), were significant and comparable with some others previously described. In addition, the location of the two opioid peptides, VV-hemorphin-7 and LVV-hemorphin-7, revealed the existence of a "strategic zone" both in the bovine and human beta-chains of hemoglobin.


In vitro evolution of cisplatin/DNA monoadducts into diadducts is dependent upon superhelical density. DNA binding of antitumor platinum(II) compounds accounts for cellular toxicity. Binding of cis-dichlorodiammineplatinum(II) (cis-DDP) to DNA involves the transient presence of monoadducts which evolve in a second phase into difunctional lesions which are far more toxic than the monoadducts. Temporal control of the monoadducts half-live is at least dependent upon the chemical nature of the cis-platinum derivative and the secondary structure of DNA. The effect of the degree of DNA superhelicity on the binding of cis-platinum derivatives as well as on the evolution of monofunctional adducts has been addressed on plasmid DNA. The rate of platination was not affected by the degree of DNA superhelicity. Similarly, when the evolution of the lesions was complete, no variation of toxicity was found with different populations of topoisomers, as determined by bacterial transformation efficiency. In contrast, when the kinetic of difunctional lesions formation was controlled in vitro, we observed a higher rate of formation on a supercoiled plasmid by comparison with a relaxed one. This result suggests that platinum-DNA adduct toxicity could be modulated by the topology of the chromosome.


Biosynthesis of sphingolipids: dihydroceramide and not sphinganine is desaturated by cultured cells. Radioactively labeled N-[1-14C]-octanoyl-sphinganine and D-erythro-[3-3H]-sphinganine were administered in parallel experiments to neuroblastoma cells B 104. A time dependent formation of ceramide with a double bond in its sphingoid backbone was observed in both cases. In the presence of fumonisin B1 (25 microM), a strong inhibitor of sphinganine N-acyltransferase, desaturated ceramide was formed only when cells were fed with N-[1-14C]-octanoyl-sphinganine but not with [3-3H]-sphinganine. Thus, the introduction of the double bond occurs only at the level of dihydroceramide, after N-acylation of sphinganine. It is now obvious that sphingosine is not a biosynthetic intermediate but exclusively a catabolic product of cellular sphingolipids.


Memory of butyrate induction by the Moloney murine sarcoma virus enhancer-promoter element. We reported previously that a housekeeping gene could be converted to a butyrate-inducible gene by replacing its cognate promoter with the Moloney murine sarcoma virus enhancer-promoter element. In this study we report that the activated transcriptional state could be propagated from mother to daughter cells after the withdrawal of the inducer.


Animal histo-blood group ABO genes.

Animal histo-blood group ABO genes. Sequences homologous to the human histo-blood group ABO genes are present in the genomic DNA of various mammals. We have PCR-amplified, subcloned, and sequenced a portion of these genes from several species of primates and found high conservation of the nucleotide as well as the deduced amino acid sequences during evolution.


The interaction of decorin core protein fragments with type I collagen. To further define the molecular interaction between decorin and type I collagen we generated a 20 kD fragment containing the N-terminal half of the core protein by Endoproteinase Arg C digestion and a 40 kD fragment including all leucine-rich repeats in the central part of decorin core by cleavage with 2-nitro-5-thiocyanobenzoate. The fragments did not influence collagen fibril formation, even at high concentration, and radioactive fragments showed little binding to collagen fibrils. Our observations suggest that neither the N-terminal half nor the central leucine-rich repeats of the decorin core protein can, by itself, interact fully with fibrillar collagen.


Phenylmethylsulfonyl fluoride stimulates proteolysis of nuclear proteins from chick liver. The degradation of H1 histone and high mobility group (HMG) nonhistone proteins was stimulated when the homogenate from chick liver was incubated in the presence of phenylmethylsulfonyl fluoride (PMSF). Two proteinase inhibitors, elastatinal and chymostatin, significantly inhibited the PMSF-stimulated degradation of H1 histone and HMG proteins. On the contrary, other proteinase inhibitors like leupeptin, pepstatin, trypsin inhibitor, antipain, o-phenanthroline and EDTA had no effect on the degradation of the nuclear proteins. These results warn the researcher to be cautious while using PMSF for preparation of nuclear proteins such as H1 histone and HMG proteins.


Brevinin-1 and -2, unique antimicrobial peptides from the skin of the frog, Rana brevipoda porsa. Two unique antimicrobial peptides named brevinin-1 and -2 were isolated from the skin of the frog, Rana brevipoda porsa. Both of the peptides did not have any structural homology with bombinin nor magainin; the frog skin derived-antimicrobial peptides isolated from Bombina and Xenopus, nor even with other known antimicrobial peptides of non-amphibian origin. The minimum inhibitory concentration of brevinin-1 against the growth of St. aureus and E. coli was determined to be 8 micrograms/ml and 34 micrograms/ml while that of brevinin-2 was 8 micrograms/ml and 4 micrograms/ml, respectively, indicating the difference of the two peptides in the antimicrobial selectively on Gram-positive and Gram-negative bacteria.


Therapeutic effects of superoxide dismutase derivatives modified with mono- or polysaccharides on hepatic injury induced by ischemia/reperfusion. Therapeutic effects of four types of recombinant superoxide dismutase (SOD) derivatives, conjugates with polysaccharides, carboxymethyl (SOD-CMD) and diethylaminoethyl (SOD-DEAED) dextrans and galactosylated (Gal-SOD) and mannosylated (Man-SOD) derivatives, on hepatic ischemia/reperfusion injury were studied in rats. Hepatic injury induced by transient occlusion and subsequent reflow of hepatic blood was evaluated by the analysis of biliary excretion of bromosulfophthalein (BSP) injected intravenously. At a dose of 10000 units/kg, native SOD and SOD-DEAE did not show any significant effect and SOD-CMD showed slight effect. On the other hand, Gal-SOD and Man-SOD, targeted to the liver parenchymal and nonparenchymal cells, respectively, by a receptor-mediated endocytosis, exhibited superior inhibitory effects. These results demonstrated that these glycosylated SOD derivatives were useful for the prevention of hepatic ischemia/reperfusion injury.


Identification of the fatty acid binding site on glutathione S-transferase P. Glutathione S-transferase P (GST-P) bound a series of endogenous fatty acids (C12-C18). To clarify the function and the binding site of the fatty acids, interaction between fatty acids and GST-P was investigated by using 12-(9-anthroyloxy) stearic acid conjugated with Woodward's reagent K. The fluorescence-conjugated fatty acid noncompetitively inhibited GST activity. After GST-P was covalently labeled with the fatty acid, the enzyme was digested with Lysyl Endopeptidase. From the peptide mapping, a single fluorescence-labeled peptide was obtained. By the sequence analysis, the peptide binding fatty acid was determined as the residues of 141-188 from the amino terminus.


Dual role of S-nitrosocaptopril as an inhibitor of angiotensin-converting enzyme and a nitroso group carrier. The S-nitroso derivatives of captopril can act as an inhibitor of an angiotensin-converting enzyme in the presence of thiol such as glutathione. S-Nitrosocaptopril also rapidly transfers its nitroso moiety to a heme protein, which is presumably the responsible mechanism for the activation of guanylate cyclase. These results suggest that S-nitrosocaptopril may serve as an effective hypotensive agent.


Substrate preference of metalloproteinases secreted by ts-110 Moloney murine sarcoma virus-transformed normal rat kidney cells. In this study, the two forms of affinity-purified transformation-associated proteins (TAPs) (68 and 64 kD) were shown to have different substrate preferences. For the 68-kD TAP, the order of substrate preference was collagen types I, III, and V; fibronectin; gelatin; and collagen IV. For the 64-kD TAP, the order of substrate preference was collagen I, III, and V and gelatin. The 64-kD TAP did not cleave collagen IV and fibronectin. We also found a 71-kD metalloproteinase in the concentrated purified TAPs that reacted only weakly with a TAP monoclonal antibody and showed this substrate preference: collagen I, III, and V; gelatin; and collagen IV. Whether this 71-kD TAP is a new member of the rat metalloproteinase family will be investigated.


A receptor-binding peptide from human interleukin-6: isolation and a proton nuclear magnetic resonance study. In order to locate the receptor-binding region of human interleukin-6 (IL-6), twelve peptide fragments were prepared by digestion of IL-6 with lysylendopeptidase. A significant activity of the receptor-binding was observed only for a peptide Ile88-Lys121, although the activity was estimated at 10(4)-fold less than that of intact IL-6. Solution structure of the peptide Ile88-Lys121 was analyzed by using two-dimensional nuclear magnetic resonance (NMR) spectroscopy. The results indicate the presence of alpha-helices in the regions Leu93-Phe106 and Glu110-Ser119. On the basis of the NMR data, we also prepared two peptides. Four-fold less binding activity than that of the peptide Ile88-Lys121 was observed for the peptide Ile88-Arg105, but no activity for the peptide Glu110-Lys121. These results suggest that the helical peptide Ile88-Arg105 composes a part of the receptor-binding region.


Invertebrate aspartyl/asparaginyl beta-hydroxylase: potential modification of endogenous epidermal growth factor-like modules. An invertebrate alpha-ketoglutarate-dependent aspartyl/asparaginyl beta-hydroxylase, which posttranslationally hydroxylates specific aspartyl or asparaginyl residues within epidermal growth factor-like modules, was identified, partially purified and characterized. Preparations derived from two insect cell lines catalyzed the hydroxylation of the expected asparaginyl residue within a synthetic epidermal growth factor-like module. This activity was found to be similar to that of the purified mammalian aspartyl/asparaginyl beta-hydroxylase with respect to cofactor requirements, stereochemistry and substrate sequence specificity. Furthermore, recombinant human C1r, expressed in an insect cell-derived baculovirus expression system, was also found to be hydroxylated at the expected asparaginyl residue. Thus, these results establish the potential for invertebrate aspartyl/asparaginyl hydroxylation. Since several invertebrate proteins known to be required for proper embryonic development contain a putative consensus sequence that may be required for hydroxylation, the studies presented here provide the basis for further investigations concerned with identifying hydroxylated invertebrate proteins and determining their physiologic function.


A Tat antagonist inhibits HIV-1 induction in naturally infected and experimentally infected T cells. Ro 5-3335, a novel antagonist of human immunodeficiency virus type 1 (HIV-1) Tat activity, inhibits acute and chronic HIV-1 infection in T lymphocytes. Here we describe the effects of Ro 5-3335 on the accumulation of viral DNA during primary infection, the induction of virus from a latently infected cell line, and the expression of virus upon activation of naturally infected T cells. Ro 5-3335 permitted initial DNA synthesis during primary infection, but inhibited the subsequent increase in viral DNA copy number. The induction of HIV-1, as determined by the synthesis of p24 core antigen, was inhibited by 99% by Ro 5-3335 in both the model cell line and naturally infected T cells.


Regulation by thyroid hormone of the synthesis of a cytosolic thyroid hormone binding protein during liver regeneration. To understand the regulation by thyroid hormone, 3,3',5-triiodo-L-thyronine (T3), of the synthesis of a cytosolic thyroid hormone binding protein (p58-M2) during liver regeneration, the synthesis of p58-M2 was evaluated. The synthesis of p58-M2 was measured by metabolic labeling of primary cultures derived from the regenerating liver of euthyroid, hypo- or hyperthyroid rats. During regeneration, the increase in the liver/body weight ratio is approximately 25% higher in hyper- than in hypothyroid rats. However, T3 has no effect on the rate of overall liver regeneration observed in four days. In mature liver, T3 increased the synthesis of p58-M2 by approximately 2.5-fold. During regeneration, however, the change in the synthesis of p58-M2 varied with the thyroid status. In euthyroid rats, the synthesis of p58-M2 continued to increase up to 2-fold during liver regeneration. In hyperthyroid rats, after an initial increase by 1.5-fold on day 1, the synthesis of p58-M2 subsequently declined during regeneration. In hypothyroid rats, the synthesis of p58-M2 remained virtually unchanged during regeneration. These results indicate that T3 regulates the synthesis of p58-M2 in mature and regenerating liver.


Regulation of ATP-citrate lyase at transcriptional and post-transcriptional levels in rat liver. The amounts of ATP-citrate lyase in liver cytosol began to increase at 12 hours after refeeding a high-carbohydrate diet and further increased until 48 hours. The amounts of the ATP-citrate lyase mRNA began to increase at 6 hours and reached to a maximum level at 12 hours, followed by decrease to a very low level until 48 hours. The elevated amount of the ATP-citrate lyase mRNA reflected on the increase of ATP-citrate lyase content in the first 24 hours, but these two parameters were not paralleled thereafter. The transcriptional activity of ATP-citrate lyase gene in nuclei of rat liver began to increase at 4 hours and further increased to reach a maximum level of 24 fold at 12 hours, maintaining a high level of 17 fold until 48 hours. The elevation of transcriptional activity of ATP-citrate lyase gene preceded the increase of ATP-citrate lyase mRNA content in the liver cytosol by 2 hours, and its increasing pattern was similar to changes of mRNA content until 12 hours. However, while the transcriptional activity remained at a high level until 48 hours, the ATP-citrate lyase mRNA concentration in the cytosol decreased after 12 hours.


Differentiative changes in fucosyltransferase activity in newborn rat epidermal cells. An enzymatic activity catalyzing the transfer of L-fucose from GDP-L-fucose to a glycoprotein that is associated with the surfaces of the basal cells has been found in the membranous fraction of the cutaneous epidermis from the newborn rat. This fucosyltransferase which is located in the differentiated cells alters the acceptor glycoprotein's lectin-binding specificity from the Isolectin I-B4 of Griffonia simplicifolia (GS I-B4) to the Agglutinin I of Ulex europeus (UEA) and could be responsible for the same change in lectin-binding specificity that occurs as the epidermal basal cell differentiates. Another membraneous fucosyltransferase that can use asialofetuin--but not the GS I-B4-binding glycoprotein--as an acceptor, is also present in the membraneous fraction.


Novel inhibitor of phospholipase A2 with topical anti-inflammatory activity. Activation of a phospholipase A2 (PLA2) is a key step in the production of precursors for the biosynthesis of lipid mediators of inflammation. Inhibition of this enzyme could result in the suppression of three important classes of inflammatory lipids, prostaglandins, leukotrienes and platelet activating factor (PAF), and offers an attractive therapeutic approach to design novel agents for the treatment of inflammation and tissue injury. In this report we describe a novel compound, BMS-181162 4(3'-carboxyphenyl)-3,7-dimethyl-9(2",6"6"-trimethyl-1"-cyclohexenyl),++ +2Z,4E,6E, 8E-nonatetraenoic acid which specifically inhibits a 14 kD human PLA2 and effectively blocks phorbol ester induced skin inflammation in mice. BMS-181162 is the first reported specific inhibitor of PLA2 and its specificity may make useful tool in the dissection of the role of PLA2 in the inflammatory process.


Methyl jasmonate conditions parsley suspension cells for increased elicitation of phenylpropanoid defense responses. Pre-incubation of suspension-cultured parsley cells with methyl jasmonate greatly enhances their ability to respond to fungal elicitors by secretion of coumarin derivatives. The effect is most pronounced at relatively low elicitor concentration and also observed for the incorporation of esterified hydroxycinnamic acids and of "lignin-like" polymers into the cell wall. These three responses correspond to defense reactions induced locally when a fungal pathogen attacks plant cells. In contrast, the conditioning of parsley cells by the signal substance methyl jasmonate is reminiscent of the developmental nature of systemic acquired resistance and renders the cells more effective for the elicitor-induced local defense reactions.


The glutathione conjugates of tert-butyl hydroquinone as potent redox cycling agents and possible reactive agents underlying the toxicity of butylated hydroxyanisole. The glutathione conjugates of tert-butyl hydroquinone, a metabolite of butylated hydroxyanisole (BHA), possess redox potentials which are much higher as compared to the non-conjugated hydroquinone (0.36 V for the hydroquinone and 1.2-1.4 V for the conjugates). As a result, the redox cycling activity of the conjugates, as measured by oxygen consumption in the presence of a reducing agent, is increased tenfold as compared to the non-conjugated hydroquinone. Since evidence for both oxidative damage and the involvement for glutathione in the toxicity of butylated hydroxyanisole is available, this mechanism may be involved in the toxic action of this compound.


Guanosine 5'-O-(3-thiotriphosphate) causes endothelium-dependent, pertussis toxin-sensitive relaxations in porcine coronary arteries. To determine whether direct stimulation of endothelial G-proteins causes relaxations of the underlying vascular smooth muscle, the effects of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and sodium fluoride were studied in porcine coronary arteries and endothelial cells. Isometric tension was measured in coronary rings contracted with prostaglandin F2 alpha. GTP gamma S (in the presence of saponin) and sodium fluoride (in the presence of AlCl3) relaxed rings with, but not those without endothelium. The responses were inhibited by nitro-L-arginine and pertussis toxin. In membrane fractions of coronary endothelial cells, GTP gamma S and sodium fluoride inhibited the ADP-ribosylation of G-proteins catalyzed with [32P]-NAD and pertussis toxin. These data suggest that direct stimulation of G-proteins in endothelial cells by GTP gamma S and sodium fluoride causes a pertussis toxin-sensitive relaxation which may be attributed to the release of nitric oxide.


Activation of an adrenergic pro-drug through sequential stereoselective action of tandem target enzymes. The synthetic amino acid, 3,4-dihydroxyphenylserine (DOPS) has been of great interest for many years as an adrenergic pro-drug, since the L-threo diastereomer of DOPS can be a precursor of R-(-)-norepinephrine, the natural form of this neurotransmitter. We now report bioactivation of DOPS to the potent pharmacological agent, noradrenalone (arterenone), via sequential stereoselective action by two target enzymes--dopamine beta-monooxygenase (DBM) and L-aromatic amino acid decarboxylase (AADC)--acting in tandem. Enzymatic activation is stereospecific, with only the L-erythro DOPS diastereomer producing noradrenalone; this is consistent with the known stereospecificities of AADC and DBM. These results provide a heretofore unrecognized rationale for the bioactivity of L-erythro DOPS and provide a basis for the design of new adrenergic pro-drugs.


Characterization of a Gly19-->Val mutant of ram p25, a low Mr GTP-binding protein: loss of GTP/GDP-binding activity in the mutated ram p25. A substitution of Gly for Val at position 19, which corresponds to oncogenic Gly13-->Val mutation of ras p21, was introduced in a low Mr GTP-binding protein, ram p25. The protein was expressed in cytosolic fraction of Escherichia coli and purified by using specific antibody raised against ram p25. The mutated protein had no guanine nucleotide-binding activity although [Val13]ras p21 was reported to have. The analysis of guanine nucleotide composition of the purified [Val19]ram p25 revealed that the protein was free of nucleotide whereas the normal ram p25 bound about 1 mol of GDP per mol of protein. These results strongly suggested that some part(s) of variable regions as well as the consensus regions are important for the biochemical properties of ram p25.


Prevalence of three mutations in the Gs alpha gene among 24 families with pseudohypoparathyroidism type Ia. Pseudohypoparathyroidism type Ia (PHP-Ia), an inherited multi-hormone resistance syndrome, is associated with deficient cellular activity of the alpha-subunit of the guanine nucleotide-binding protein (Gs alpha) that stimulates adenylyl cyclase. We determined prevalence of three recently described mutations in exons 1 and 10 of the Gs alpha gene among 24 unrelated patients with PHP-Ia. Restriction analysis was used to detect two mutations that produce unique RFLPs, and allele-specific oligonucleotide hybridization was used to detect the other mutation. As none of these mutations were not found, genomic DNA was analyzed with denaturing gradient gel electrophoresis to screen for other mutations in exon 10. Mutations of the initiation codon and exon 10 in the Gs alpha gene thus rarely (< or = 4% each) cause PHP-Ia and the Gs alpha gene mutations causing PHP-Ia are heterogeneous and unique to each pedigree.


DRG: a novel developmentally regulated GTP-binding protein. Using a subtraction cloning approach we had previously isolated a series of murine cDNA clones representing the genes predominantly expressed in the embryonic brain and down-regulated during development. We now report that one of these cDNA clones encodes a novel type of GTP-binding protein. The predicted protein of 40.5 kD, named DRG, contains five structural motifs characteristic of the GTP-binding proteins. Consistently, bacterially expressed and cellular DRG proteins are capable of binding GTP in vitro. Sequences closely related to the DRG protein are found in other species including Drosophila and Halobacterium. Based on these observations, we propose that DRG represents an evolutionarily conserved novel class of GTP-binding protein which may play an important role in cell physiology.


Re-examination of [3H]mepyramine binding assay for histamine H1 receptor using quinine. [3H]Mepyramine, a potent antagonist of the histamine H1 receptor, has been widely used as a radioligand binding assay for the H1 receptor. Previously, we purified a mepyramine binding protein (MBP) from rat liver, but found that its partial amino acid sequences were very similar to those of debrisoquine 4-hydroxylase isozymes (P450 db1 and db2), which are members of the superfamily of cytochrome P450. Using cloned histamine H1 receptor cDNA, we found that [3H]mepyramine could bind only the H1 receptor and did not bind MBP in the presence of 10(-5) M quinine, an inhibitor of debrisoquine 4-hydroxylase isozymes. We developed a method to determine the contents of the H1 receptor and MBP separately using [3H]mepyramine and quinine and found that MBP is abundant in certain areas of bovine brain.


Immunocytochemical expression and localization of protein kinase C in bovine aortic endothelial cells. Total PKC activity in BAEC incubated for 24 hrs in either 10% serum (FBS) or serum-deprived media (SDM) was similar. However, most of the activity (69%) in the FBS group was detected in the particulate fraction, while it was mainly in the cytosolic fraction (66%) in the SDM group. By confocal microscopy, there was diffuse cytoplasmic localization of the antibodies to the alpha and beta PKC isoforms. gamma PKC was not detected. Treatment of FBS or SDM cells with a phorbol ester resulted in an increase in PKC activity with translocation to the particulate fraction. PKC alpha immunofluorescence redistributed to the perinuclear region whereas PKC beta staining remained mostly cytosolic. Calphostin C, a PKC inhibitor, prevented the phorbol ester-induced increase in PKC activity and translocation.


Molecular cloning of the mouse S-adenosylmethionine decarboxylase cDNA: specific protein binding to the conserved region of the mRNA 5'-untranslated region. The nucleotide sequence of a cDNA encoding the proenzyme of mouse S-adenosylmethionine decarboxylase (AdoMetDC) including 257 nucleotides of the 5' untranslated region has been determined. Comparison of the nucleotide sequence of the mouse 5' untranslated region with those of other mammals shows it to be highly conserved. The 52 nucleotides upstream from the translation initiation codon are identical in human, rat, bovine and mouse. The polyamines, spermidine and spermine, have been shown to inhibit AdoMetDC mRNA translation. An RNA gel retardation assay demonstrated that a cytoplasmic extract from mouse brain forms an RNA-protein complex with the completely conserved 5' untranslated sequence and that the complex formation is highly dependent on the presence of spermine. Crosslinking by UV irradiation shows that the complex contains a 39-kDa protein interacting with the 5' untranslated sequence. These data demonstrate spermine-dependent specific protein binding to a highly conserved 5' untranslated region of an mRNA translationally regulated by polyamines.


Modulation of transient type K channel cloned from rat heart. We have cloned a transient type K channel from rat heart (RH10) and coexpressed a metabotropic glutamate receptor (mGluR5) to study the functional modulation of RH10 coupled to the phosphatidylinositol (PI) hydrolysis. Stimulation of mGluR5 suppressed peak amplitude of RH10 current and affected voltage dependence of activation and inactivation of the channel.


3H-uridine uptake in human leukemia HL-60 cells exposed to extremely low frequency electromagnetic fields. Human leukemia HL-60 cells in vitro were exposed or sham-exposed to a 60 Hz electric (3.40 mV/m) or magnetic 10 G (1 muT) field for 5 hr in an attempt to replicate the results of a previously published report (1) of increased uptake of [3H] uridine in response to similar exposure conditions. The results of the present experiments indicated no treatment effect of the fields on uridine incorporation. The ability to detect differences in [3H] uridine uptake were confirmed in a negative control experiment. A 'negative control' experiment demonstrated a statistically significant increase in 3H-uridine uptake for cells at 37 degrees C relative to those at 4 degrees C.


Purification and characterization of bovine brain gamma-aminobutyraldehyde dehydrogenase. gamma-Aminobutyraldehyde dehydrogenase was purified to homogeneity from bovine brain. The molecular weight of the native enzyme and subunit were 230,000 and 58,000, respectively. The Km value for gamma-aminobutyraldehyde and NAD+ were 154 microM and 53 microM, respectively. The optimum pH and temperature were 8.0 and 37 degrees C, respectively. N-terminal sequence of the enzyme is as follows: NH2-S-A-A-T-Q-A-V-P-T-P-N-Q-Q-COOH. The enzyme migrates on isoelectric focusing with pI = 6.5. Enhancement of the enzyme activity by polyamine, Mn2+, Mg2+ and inhibition by gamma-aminobutyric acid and Zn2+ will enhance the limited information on regulation of the gamma-ABALDH activity and GABA metabolism to some extent.


Regulation of the GTPase activity of the ras-related rap2 protein. The small GTP-binding protein rap2A exhibits a high level of identity with rap1 and ras proteins (60% and 46%, respectively). Nevertheless, its intrinsic GTPase activity is not stimulated by ras-GAP, and unlike the rap1A protein, it cannot compete with ras proteins for their interaction with ras-GAP. In addition, rap1-GAPm that is highly active on the GTPase activity of the rap1A product, also stimulates the GTPase activity of the rap2A protein but with a 30-40-fold lower efficiency. An activity that greatly stimulated the GTPase activity of the rap2 protein (rap2-GAP) was found in bovine brain cytosol and purified. However, it copurified with the cytosolic form of rap1-GAP and was more efficient at stimulating the GTPase activity of the rap1 protein; this 55 kD polypeptide, that is recognized by an antibody raised against rap1-GAPm, likely represents a degraded and soluble form of the full size 89 kD molecule. In bovine brain membranes, a weak GAP activity toward the rap2A protein was also detected; however, it was also attributable to the membrane-associated rap1-GAPm. Thus, it appears that a single rap-GAP protein, complete or degraded, is able to stimulate the GTPase activity of both rap1 and rap2 proteins.