The contractile apparatus in vascular smooth muscle cells of spontaneously hypertensive rats possess increased calcium sensitivity: the possible role of protein kinase C. The purpose of the present investigation was to compare calcium sensitivity of contractile machinery in aorta and portal vein smooth muscle cells (SMC) in normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive Okamoto rats (SHR), and to shed light upon the mechanisms of possible differences. Investigations into calcium sensitivity of SMC myofilaments can only be made on skinned muscular strips. The vascular strips were made hyperpermeable by detergent skinning with saponin. The isometric calcium-induced contractions of SMC were recorded using a force displacement transducer coupled to a physiograph. It was shown that the pCa-tension (negative logarithm of calcium concentration versus tension) relationship for aorta and portal vein SMC in SHR shifted to the left in comparison with WKY rats. Putative protein kinase C inhibitors 1-(S-isoquionolinyl-sulfonyll)-2-methylpiperasine (H-7) and polymyxin B shifted the pCa-tension relationship more significantly to the right in the SMC of SHR than in WKY rats. It has also been shown that H-7 and polymyxin B sharply reduced the maximum tension developed by SMC in SHR whilst causing a non-significant decrease in maximum tension of SMC from WKY rats. These results are consistent with higher protein kinase C activity in SMC of SHR. These results indicate that the increase in calcium sensitivity of vascular SMC contractile machinery in SHR may be linked with the increase in their protein kinase C activity.


Insulin resistance in spontaneously hypertensive rats but not in deoxycorticosterone-salt or renal vascular hypertension. To investigate whether the reported association between insulin resistance and hypertension in spontaneously hypertensive rats (SHR) is a primary defect or a secondary phenomenon in hypertension. Comparisons of glucose metabolism between three groups of hypertensive rats: deoxycorticosterone (DOCA)-salt hypertensive rats; two-kidney, one clip renovascular hypertensive (RVH) rats; SHR; and their respective control groups. There was also an additional group of weight-matched SHR and respective Wistar-Kyoto (WKY) controls. A trace amount of 3H-deoxyglucose (3H-DOG) was administered in vivo to evaluate its plasma half-life and tissue uptake. In vitro adipose tissue segments were incubated with 14C-glucose and increasing doses of insulin. Compared with age-matched WKY rats, SHR had significantly higher insulin levels, longer plasma half-life and lower 3H-DOG uptake by heart and striated muscle. Plasma glucose levels and incorporation of 14C-glucose into CO2, triglycerides and glycogen by adipose tissue in response to increasing insulin concentrations was similar for both groups of SHR and WKY rats. No differences were found between hypertensive rats and controls in either the DOCA or RVH groups. Evidence of insulin resistance in spontaneous, but not secondary, rat hypertension indicates that the resistance is a primary rather than a secondary event in hypertension.


Characterization of angiotensin converting enzyme in isolated cerebral microvessels from spontaneously hypertensive and normotensive rats. Abnormalities in the vascular renin-angiotensin system have been hypothesized to contribute to the pathogenesis and complications of hypertension. In animal models of hypertension, there is wide variation in reported vascular angiotensin converting activity, particularly in cerebral microvessels. In this study, we sought to characterize, quantitate and compare cerebral microvessel angiotensin converting enzyme (ACE) in genetically hypertensive rats and normotensive rats. Brain microvascular ACE from 14-week-old spontaneously hypertensive rats (SHR) was measured and compared with ACE from brain microvessels of normotensive Wistar-Kyoto (WKY) controls. Isolated cerebral microvascular ACE was measured using two methods, enzyme kinetic assay or radioligand binding assay. In SHR, cerebral microvessel ACE was of similar activity and concentration and had similar ligand binding affinities to WKY rats. Plasma ACE activity was significantly elevated in WKY rats compared with SHR. Cerebral microvascular ACE is similar in SHR and WKY rats. Microvascular ACE is unlikely to participate in the pathogenesis or complications of hypertension in this model.


A comparison of the effects of renin inhibition and angiotensin converting enzyme inhibition upon bradykinin potentiation. The goal of the present study was to show that, in contrast to an angiotensin converting enzyme (ACE) inhibitor, Ro 42-5892, a new renin inhibitor, can block the renin-angiotensin system without potentiating skin reactions induced by bradykinin. Potentiation of skin reaction to i.d. injections of bradykinin and histamine was evaluated in guinea pigs in the presence and absence of the drug (placebo, Ro 42-5892 or cilazapril). The elimination rate of radioactive bradykinin in blood was measured in other groups of guinea pigs treated with the same drugs. Maximal effective doses of each drug were used. Measurements of erythema area induced by bradykinin and histamine injection were performed using a digital planimeter. Radioactive bradykinin was measured in blood by high-performance liquid chromatography and followed over 40 min. The ACE inhibitor cilazapril increased the area of erythema induced by bradykinin but not that induced by histamine. In contrast, Ro 42-5892 did not potentiate the effect of bradykinin. In addition, cilazapril did not change the elimination rate of i.v. radioactive bradykinin in blood. These results suggest that potentiation of bradykinin-induced skin reaction by cilazapril is due to a tissular (and not systemic) inhibition of ACE and does not occur with Ro 42-5892. Thus, side effects such as rash, angioneurotic edema or cough, which have been attributed to bradykinin accumulation by ACE inhibitors, may not occur with the use of specific renin inhibitors such as Ro 42-5892.


High levels of plasma atrial natriuretic factor and impaired left ventricular diastolic function in hypertensives without left ventricular hypertrophy. To seek possible correlations between plasma atrial natriuretic factor (ANF) and left ventricular diastolic function (LVDF) in hypertensive patients. Since LVDF abnormalities can be detected in patients with normal left ventricular mass, we studied a group of hypertensive patients without left ventricular hypertrophy. Untreated hypertensive patients (n = 23) and normotensive control subjects (n = 19) were studied. LVDF indices were obtained by M-mode and pulsed Doppler echocardiography. Blood samples for plasma ANF were taken in the recumbent position from subjects on normal-sodium intake. Plasma ANF levels were significantly higher in hypertensive patients than in normotensive subjects. All indices for systolic function were normal in both normotensive subjects and hypertensive patients. Left atrial diameter was significantly higher for hypertensive patients than for normotensive subjects. Considering LVDF, all indices for ventricular filling were found to be altered, on average, in hypertensive patients, the only exception being peak early velocity. In addition, significant correlations were found between plasma ANF and the pulsed Doppler parameters of left ventricular filling, peak atrial velocity and the peak early:peak atrial velocity ratio. Overall correlations between plasma ANF and left atrial diameter, and between left atrial diameter and left ventricular mass index were also observed. The high levels of plasma ANF observed in our hypertensive patients and their correlation with the LVDF indices (which mainly reflect the atrial contribution to ventricular filling) could be the result of an increased atrial stretch due to diastolic ventricular dysfunction. This may exist in hypertensive patients before the development of ventricular hypertrophy.


The paradoxical role of left ventricular hypertrophy in wall stress-related arrhythmia. To investigate the interrelationship between arrhythmias provoked by acute pressure changes, and the presence of left ventricular hypertrophy and electrolyte imbalances. An isolated working rat heart model was used in a prospective comparison of the effects of acute pressure changes in hypertensive and normotensive hearts during perfusion with perfusate containing differing electrolyte compositions. An experimental laboratory study. STUDY MATERIALS: Forty-four rat hearts (20 hypertensive, 24 normotensive). Hearts were subjected to sudden pressure changes of varying sizes during perfusion with two different electrolyte solutions and the arrhythmias provoked were recorded. The size of the pressure change necessary to provoke arrhythmias, and the amount and severity of arrhythmias provoked by equivalent-sized pressure changes. During perfusion with normal electrolyte concentrations, no hypertrophied hearts developed arrhythmia compared with more than half of the normal hearts during equivalent-sized pressure changes, and a much larger pressure increase was necessary to produce any arrhythmia in the hypertrophied hearts. During perfusion with cation-depleted perfusate, arrhythmias significantly increased in both groups of hearts, but the pattern was reversed; more than half of the hypertrophied hearts compared with none of the normal hearts developed ventricular tachycardia during equivalent-sized pressure increases, whilst the minimum pressure change necessary to provoke arrhythmia became significantly smaller in the hypertrophied hearts compared with the normal hearts. Left ventricular hypertrophy plays a paradoxical role in the development of arrhythmias in this model. It appears to protect the heart from developing arrhythmias in response to sudden pressure changes when electrolyte concentrations are normal. However, it also seems to lead to a marked increase in the sensitivity of the myocardium to pressure changes during perfusion with low levels of potassium and magnesium. Under these conditions, potentially fatal arrhythmias can be readily provoked by relatively small pressure changes. These results may be of importance for the management of hypertension and may provide insight into some of the mechanisms underlying sudden death in hypertension. The findings may also be of relevance to other cardiac diseases associated with ventricular hypertrophy or abnormal wall stress.


The cardiac functional reserve in elderly hypertensive patients with abnormal diurnal change in blood pressure. To evaluate the left ventricular function of hypertensive patients with abnormal diurnal change in blood pressure. We compared left ventricular structural and functional characteristics between hypertensive patients with a normal diurnal change in blood pressure (H2 group) and those with a nocturnal blood pressure increment (H1 group) using echocardiography. The study group consisted of 36 hypertensives and 16 normotensives whose 24-h ambulatory blood pressure monitorings were measured non-invasively. The hypertensive group was subdivided into the H1 group, consisting of 11 patients (76 +/- 7 years), and the H2 group with 25 patients (73 +/- 7 years). The normotensive control group had a mean age of 73 +/- 6 years. Echocardiographic examinations were performed before and at the end of isometric exercise (handgrip for 3 min) and isoproterenol infusion (0.02 micrograms/kg per min for 5 min). The left ventricular mass index in the H1 group was significantly greater than in the H2 or control group. Left ventricular fractional shortening (LVFS) at rest in the H1 group was also significantly greater than in the other two groups. However, the peak late: early diastolic filling ratio, which indicated diastolic function, significantly deteriorated in the H1 group compared with the H2 and control groups. Furthermore, changes in LVFS after isometric exercise in the H1 group were more suppressed than in the H2 or control group. In addition, a significantly lower increment in LVFS after isoproterenol was observed in the H1 group compared with the H2 or control group. The H1 group had greater left ventricular mass and impaired left ventricular functional reserve than the H2 group.


Ambulatory blood pressure measurement, smoking and abnormalities of glucose and lipid metabolism in essential hypertension. Casual (mercury sphygmomanometer) and ambulatory blood pressure measurements were determined in 61 subjects with sustained essential hypertension. Patients were classified into three subgroups: smokers or non-smokers; patients with or without hyperglycemia; and patients with or without plasma lipoprotein abnormality. Mean casual blood pressure were shown to be identical in these three subgroups. When ambulatory blood pressure was analyzed, smokers exhibited a significant increase in pulse pressure exclusively during the activity period, whereas diastolic blood pressure and mean arterial pressure (MAP) were not modified in comparison with controls. Patients with abnormal plasma glucose showed a significant increase in systolic and pulse pressure during both activity and non-activity periods, with a slight increase in MAP during the activity period. Patients with and without plasma lipid abnormality displayed similar ambulatory blood pressure. The study provides evidence that, in spite of similar casual blood pressure levels among smokers and non-smokers, as well as among those with elevated fasting glucose levels, smokers and patients with hyperglycemia have a higher systolic and pulse pressure during 24-h monitoring, pointing to the possible role of cyclic stress in the deterioration in the structure of the hypertensive arterial wall.


Effect on sleep--but not on blood pressure--of nocturnal non-invasive blood pressure monitoring. Nocturnal non-invasive ambulatory blood pressure monitoring inevitably causes an undesirable external stimulus due to the cuff pressure and, for some monitors, disturbing compressor sound. The objective of the present study was to determine whether non-invasive automated blood pressure monitoring during sleep provokes arousal and changes in blood pressure and/or heart rate. Sleep response and blood pressure reaction during and immediately after blood pressure monitoring were studied by means of simultaneous electroencephalography and blood pressure recordings. Blood pressure and electroencephalogram were recorded simultaneously in 24 subjects (10 hypertensive, 14 normotensive). Blood pressure was registered with a non-invasive automatic blood pressure monitor every 20 min. Inflation and deflation of the cuff were registered on one of the electroencephalogram channels by means of a small pressure meter attached to the cuff. For each subject, blood pressure during uninterrupted sleep was compared with that during arousal provoked by the recordings. Blood pressure recording caused an arousal in 67% of the recordings. During 33% of the recordings, sleep continued. Neither systolic nor diastolic blood pressure differed significantly for recordings during 'uninterrupted sleep' when compared with arousal. Heart rate was significantly faster during arousal than during uninterrupted sleep. Analysed separately, hypertensive subjects showed an overall blood pressure response close to that of normotensive subjects. There was a significant trend towards lower blood pressure, parallel with deeper sleep. The results of this study show that non-invasive ambulatory blood pressure monitoring during sleep accurately records basal blood pressure and can distinguish blood pressure during superficial sleep from blood pressure during deep sleep. Sleep is often disturbed by blood pressure monitoring but, irrespective of whether recording provokes arousal, monitored blood pressure is the same.


A dietary fibre supplement in the treatment of mild hypertension. A randomized, double-blind, placebo-controlled trial. To study the effects of a dietary fibre supplement given as monotherapy upon blood pressure in mildly hypertensive patients. The investigation was performed as a prospective randomized, double-blind, placebo-controlled trial for 3 months. Patients attending an outpatient hypertension clinic in a hospital. Hypertensive patients with a minimum of two diastolic blood pressure (DBP) readings greater than 90 mmHg during a 2-week run-in period were included. Of the 65 patients enrolled, 63 were randomized (32 fibre, 31 placebo). Six patients did not complete the trial. Patients were treated with either fibre (7 g/day) or matching placebo. Based on previous studies, the a priori hypothesis was that dietary fibre supplementation could reduce blood pressure in hypertensive patients. Body weight was significantly reduced in the fibre group. Dietary fibre significantly reduced DBP and fasting serum insulin. However, no correlation between changes in body weight and systolic blood pressure or DBP was found. A dietary fibre supplement can lower DBP in mildly hypertensive patients independent of changes in body weight.


Cushing's syndrome associated with lung tumors. The production of corticotropin or corticotropin-releasing factor by non-pituitary, non-adrenal tumors may rarely be associated with an overt clinical expression of hypercortisolism. Recent studies have emphasized the importance of careful thoracic evaluation when such ectopic hormone secretion is suspected.


Effective modulation of the haematopoietic toxicity associated with zidovudine exposure to murine and human haematopoietic progenitor stem cells in vitro with lithium chloride. The drug zidovudine (AZT), a synthetic thymidine analogue, has been used in the treatment of acquired immunodeficiency syndrome (AIDS). Clinical use of zidovudine has induced haematopoietic toxicity manifested by anaemia, neutropenia, frequent thrombocytopenia, and overall bone-marrow suppression. The monovalent cation lithium has been shown to be an effective agent capable of modulating several aspects of haematopoiesis such as the induction of neutrophilia, thrombopoiesis, and protection against suppression of haematopoietic progenitor stem cells following exposure to anticancer drugs and/or radiation in the treatment of malignant disease. We here report the results of studies designed to evaluate the effectiveness of lithium in reversing and/or protecting against either murine or human bone marrow derived haematopoietic progenitors, i.e. (CFU-GM, CFU-Meg, and BFU-E) when co-cultured in the presence of zidovudine in vitro. Lithium chloride (LiCl) reversed zidovudine toxicity to either murine or human derived CFU-GM and CFU-Meg that was optimal at a concentration of 1 mM (P less than 0.05). However, the addition of lithium failed to influence zidovudine toxicity toward either murine or human BFU-E. In summary, these results support the scant clinical studies that have described the presence of neutrophilia and/or thrombopoiesis in zidovudine-treated AIDS patients receiving lithium. In addition, these data further confirm the need for more detailed evaluation of lithium as an adjuvant agent to reduce the haematopoietic toxicity associated with the use of antiviral therapy in HIV-infected patients.


Children with condylomata acuminata.

Children with condylomata acuminata. The modes of transmission of genital human papillomavirus (HPV) infection in children are controversial. Studies have varied in reporting suspicion of sexual abuse in children with condylomata acuminata from zero to 90.9%. Possible modes of transmission include sexual, from mother to infant in utero, passage through an infected birth canal, infection of a nongenital type virus to the genital area, and nonsexual acquisition from a fomite. Seven children, ranging in age from 2 to 12 years, who had genital HPV infections were assessed for sexual abuse. An interview with each child was conducted and an examination with a colposcope of the external genitalia was performed. A shave biopsy of a representative genital lesion was obtained. The tissue was sent for HPV typing. Six of the children had perianal warts; the seventh had a labial lesion. Five of the children (71%) had been sexually abused as determined by the history, physical examination, or an investigation by Child Protective Services. Five had HPV type 6 or 11, one had HPV type 16 or 18, and one had a novel HPV type. Genital types of HPV (6 or 11, 16 or 18, and others) should alert the family physician to proceed with a careful assessment for sexual abuse. This study supports the findings of other reports that genital HPV infection can be the result of sexual abuse and points out the usefulness of HPV typing.


Physical mapping of the mec region of an Australian methicillin-resistant Staphylococcus aureus lineage and a closely related American strain. Methicillin-resistant (Mcr) staphylococci contain chromosomal DNA that is absent from Mcs cells. This extra DNA harbours the methicillin resistance determinant mec and often other resistance determinants. The mec region can differ substantially in structure among different isolates. We present studies on the mec region of a group of Staphylococcus aureus isolates prevalent in Australia and London. Southern hybridization analyses of a prototype Australian isolate, ANS46, and an isogenic Mcs deletion mutant, ANS62, allowed the physical map of the region to be extended to 55 kb. The DNA corresponding to the deletion, which includes mec and resistance determinants for mercury, cadmium (Cd) and tetracycline, amounted to 41 kb. It was bounded precisely at one end by the macrolides-lincosamides-streptogramin B (MLS)-resistance transposon, Tn554. Near the other end was an element with homology to Tn554, psi Tn554, which carried the Cdr determinant. The mec region of an American Mcr isolate, R35, was found to be virtually the same as that of ANS46, except that it lacked Tn554. Another class of American Mcr isolates, prevalent since 1987, differs markedly from ANS46 in mec region organization. However, this other American class also contains an insertion of Tn554 in the mec region, and the attachment site for this insertion was found to have significant homology to attachment sites for the Tn554 and psi Tn554 insertions in the mec region of the Australian strain. These results suggest possible roles of Tn554 and Tn554-like elements in the evolutionary variation of the mec region.


Development of topographic order in the mammalian retinocollicular projection. We have used the anterograde axon tracer 1,1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) to characterize the development of topographic order in the rat retinocollicular projection. Retinal axons were labeled by Dil injections covering 0.15-2% of peripheral temporal, nasal, superior, or inferior retina, or more central retina, in rats ranging in age from embryonic day 20 to postnatal day (P) 19. At P11-P12 and later, such injections label retinal axons that form overlapping arbors restricted to a topographically correct terminal zone covering about 1% of the superior colliculus (SC) area. At perinatal ages, though, axons labeled from each retinal site are distributed in the SC over much of its medial-lateral axis and extend caudally well beyond the rostral-caudal location of their correct terminal zone; some continue caudally into the inferior colliculus. Axons typically form side branches and often arborize at topographically incorrect positions throughout the SC; however, they appear to branch preferentially in a region that includes, but is much larger than, their correct terminal zone. The mature, retinotopically ordered projection emerges during an early postnatal remodeling period through the rapid remodeling of the early, diffuse projection. This process involves the large-scale removal of axons, axon segments, branches, and arbors from topographically inappropriate positions concurrently with a dramatic increase in branching and arborization at topographically correct locations. Quantitative measurements show that elimination of aberrant branches without loss of the primary axons contributes substantially to the development of order. By P6, fewer mistargeted axons persist, but those that do persist tend to branch or arborize more extensively in topographically inappropriate regions. By P8, the labeling patterns begin to approximate those seen at maturity. Further refinement leads to an adultlike topographic ordering of axonal arborizations by P11-P12. At maturity, some axons take very indirect routes to reach their correct terminal zone. However, such trajectory changes typically correct only small positional inaccuracies, indicating that axons and axon segments that make larger targeting errors do not survive the remodeling phase. Previous retrograde labeling studies indicate that some retinal axons make topographic targeting errors (O'Leary et al., 1986; Yhip and Kirby, 1990), but none have suggested the degree of diffuseness revealed by anterograde labeling with Dil. Our findings show that directed axon growth is inadequate as a mechanism to develop the topographic ordering of retinal axons in the rat SC. Rather, mechanisms that control the removal of mistargeted axons and promote the arborization of correctly positioned axons are critical for the development of retinotopic order.(ABSTRACT TRUNCATED AT 400 WORDS)


The morphological basis for binocular and ON/OFF convergence in tree shrew striate cortex. We used retrograde and anterograde transport methods and single-cell reconstructions to examine the projection from layer IV to supragranular layers in the tree shrew's striate cortex. We found that neurons in the ON and OFF subdivisions of layer IV (IVa and IVb, respectively) have overlapping terminal fields throughout layers II and III. Despite their overlap, these projections are organized in a highly stratified, mirror-symmetric fashion that respects the vertical position of neurons within each sublayer. Neurons in the middle of layer IV (lower IVa and upper IVb) project to layers IIIa/b, II, and I; neurons located at the edges of layer IV (upper IVa and lower IVb) project to the lower half of layer IIIc; and neurons in the middle of IVa and the middle of IVb project to upper IIIc. The stratified nature of the projections from layer IV to layer III is reminiscent of the pattern of ipsilateral and contralateral eye inputs to layer IV. Inputs from the ipsilateral eye are limited to the edges of layer IV (upper IVa and lower IVb), while those from the contralateral eye terminate throughout the depth of IVa and IVb. Thus, cells near the edges of layer IV should receive strong input from both eyes, while those in the middle of layer IV should receive mostly contralateral input. Taken together, these results suggest that the projections from layer IV to layer III bring together the information conveyed by the ON and OFF pathways, but do so in a way that matches the ocular dominance characteristics for each pathway.


Alternatively spliced sodium channel transcripts in brain and muscle. Sodium (Na) channel cDNAs were synthesized from RNA isolated from rat brain, cardiac muscle, and skeletal muscle. Partial cDNAs coding for the largest cytoplasmic loop of the Na channel were amplified with PCR. Sequence analysis of these cDNAs revealed that Na channel cDNAs originally described as brain genes were also expressed in both cardiac and skeletal muscle. Some of these cDNAs were isoforms that differed by insertions or deletions and can be explained by alternative choices of a 5' splice site. Southern blot analysis of genomic DNA confirmed the presence of introns in this region of the gene. Transcripts of multiple isoforms were detected with RNase protection in brain, heart, and skeletal muscle. Several conclusions can be drawn from the data. (1) Some rat sodium channel genes are transcribed in all excitable tissues studied here: brain, cardiac muscle, and skeletal muscle. (2) Each of these three tissues expresses multiple sodium channel genes. (3) Alternative splicing of sodium channel transcripts occurs in these tissues. (4) Expression of multiple genes and alternative splicing of the transcripts is responsible for at least seven different sodium channel mRNAs in skeletal muscle.


Sensory nerves in adult rats regenerate and restore sensory function to the skin independently of endogenous NGF. We have investigated the possible roles of NGF, and of impulse activity, in the regeneration of sensory nerves. Unexpectedly, the ability of crushed axons to regrow and to restore functional recovery of three sensory modalities in adult rat skin (A alpha-mediated touch, A delta-mediated mechanonociception, and C-fiber-mediated heat nociception) was totally unaffected by anti-NGF treatment. This finding applied even when the anti-NGF dosage was almost eight times that which entirely blocked collateral sprouting of the undamaged axons of both classes of nociceptive nerves (the A alpha-axons do not sprout in adult animals). In the same anti-NGF-treated animal, regeneration would proceed normally on the one side, while collateral sprouting was prevented on the other. Light microscopic and EM examination revealed that in the denervated skin the regenerating axons utilized the same dermal perineurial pathways followed by collaterally sprouting axons. Regeneration within these antibody-accessible pathways progressed normally during anti-NGF treatment, extending 1-2 cm beyond the former field borders, that is, into territory whose invasion by collaterally sprouting axons was totally blocked. The blood-nerve barrier is absent within the degenerating peripheral nerve trunk, a putative NGF source for regenerating fibers but not for sprouting ones. The NGF-independent regeneration was also found to be unaffected when putative spinal cord sources of NGF were eliminated by dorsal root excision. Anti-NGF treatment also failed to block regeneration across 4 mm excision gaps in the nerve trunk. The daily anti-NGF regime continued to be effective for at least 8 weeks, at which time newly evoked collateral sprouting could still be blocked. Exogenous NGF, in doses that evoke collateral sprouting de novo in normal skin, failed to influence regeneration. Finally, an electrical stimulus regime, which markedly reduces the latency of collateral sprouting, failed to affect the time to arrival of regenerating axons at the skin, or the rate of their arborization in it. We conclude that, in striking contrast to their collateral sprouting, the regeneration of nociceptive axons occurs independently of endogenous NGF and is unaffected by impulse activity. These findings further support the proposal that these two growth behaviors have basically different biological functions in the organism.


Reliability and effectiveness of transmission from exteroceptive sensory neurons to spiking local interneurons in the locust. Mechanosensory information from exteroceptive hairs on the legs of a locust is first processed in a segmental ganglion by a midline population of spiking local interneurons for use in adjustments of posture and locomotion. Each interneuron receives excitatory inputs from a characteristic array of these receptors so that the surface of a leg is mapped onto the whole population of interneurons as a series of overlapping receptive fields. The properties of this first synaptic connection, and the contributions of individual afferents forming the receptive fields of the interneurons are examined. The gain of the excitatory synaptic connection between the hair afferents and the interneurons is often high, so that a single afferent spike can lead directly to a spike in the interneuron. Repetitive spikes in a hair afferent evoke EPSPs in an interneuron that decline in amplitude but that may summate. The first EPSP in any sequence is always the largest. The high frequencies of afferent spikes that are evoked by a normal deflection of a hair saturate the synaptic connection so that the amplitude of depolarization is no greater than to a single spike. The EPSPs from two hairs in a receptive field can summate but lead to no heterosynaptic facilitation. High-frequency bursts of spikes in one afferent can reduce the postsynaptic effect of another afferent. The amplitude of the EPSPs and the gain of the synaptic connections differ markedly between the hairs that comprise the receptive field of an interneuron. There are gradients of effectiveness, generally according to the axes of the leg, with one group of adjacent hairs producing the largest-amplitude EPSPs and having the highest gains. Individual hairs may contribute to the receptive field of more than one interneuron, and the gain of these connections may differ. The complexity of a receptive field is further accentuated by the specificity of connections made by the different physiological types of hair receptors. High-threshold hairs may make synaptic connections with an interneuron, but adjacent low-threshold hairs may not. This organization of the receptive fields means that the interneurons are sensitive to certain inputs and can reliably pass on a signal from one hair. It also implies that greater weighting is given to inputs from certain regions.


Convergence of reflex pathways excited by distension and mechanical stimulation of the mucosa onto the same myenteric neurons of the guinea pig small intestine. The effects on morphologically and electrophysiologically characterized myenteric neurons of activation of intestinal reflex pathways were examined in vitro. Opened segments of guinea pig small intestine were pinned serosa down in an organ bath that had two balloons set into its base. A 5-10-mm-wide strip of myenteric plexus between the balloons was exposed from the mucosal side, and neurons were impaled with microelectrodes. Reflex pathways were stimulated by inflation of the balloons to distend the intestinal wall, and by deforming the exposed mucosal villi with a brush. Impaled neurons were classified electrophysiologically as AH-neurons or S-neurons (Hirst et al., 1974) and were injected with biocytin to determine their shapes and projections. None of the 58 AH-neurons responded to distension. In contrast, 63 of 131 S-neurons responded to distension with a burst of fast EPSPs; about one-third of the responding S-neurons received input from ascending reflex pathways, one-third received input from descending reflex pathways, and one-third received input from both ascending and descending pathways. Most neurons in this last group supplied extensive varicose branches to the tertiary plexus and were probably longitudinal muscle motor neurons. Neurons receiving input from only one pathway usually projected in the direction of that pathway; many of these were circular muscle motor neurons. Almost all neurons responding to distension were also excited by deforming the villi. Responses evoked by distension or deforming the mucosa declined when stimuli were repeated at intervals less than 10 sec. This was seen in ascending and descending pathways but was more prominent in the former. Deforming the mucosa evoked a normal response even when the response to repeated distensions had disappeared. It is concluded that distension and deforming the mucosa excite separate populations of sensory neurons to activate reflex pathways that converge onto common motor neurons and probably onto common interneurons.


Association of BEN glycoprotein expression with climbing fiber axonogenesis in the avian cerebellum. In a previous study, we have identified an avian 100 kDa membrane glycoprotein that we called BEN and demonstrated that it is transiently present in the CNS and PNS on the cell somas and axons of neurons that establish the peripheral neuronal circuitry. We report here that in the developing chick cerebellar system BEN is selectively expressed on fibers whose ingrowth and synaptogenesis pattern corresponds to that described for climbing fibers. We have constructed quail-chick chimeras in which the chick mesencephalon and anterior metencephalon were replaced by their quail counterparts, thus generating a cerebellum and mesencephalon exclusively composed of quail cells whereas the main nuclei emitting afferent fibers to the cerebellar cortex were of chick origin. Then, using species-specific monoclonal antibodies we were able to show in double staining experiments that BEN protein is specifically expressed on fibers arising from the inferior olivary nucleus. The spatiotemporal pattern of BEN expression on the climbing fibers leads us to propose that this molecule is associated with the growth of these fibers and with the establishment of synapses between them and the Purkinje cell dendritic tree.


IGF-I and IGF-II protect cultured hippocampal and septal neurons against calcium-mediated hypoglycemic damage. Insulin and insulin-like growth factors I and II (IGF-I and IGF-II) have recently been shown to have biological activity in central neurons, but their normal functions and mechanisms of action in the brain are unknown. Since central neurons are particularly vulnerable to hypoglycemia that results from ischemia or other insults, we tested the hypothesis that growth factors can protect central neurons against hypoglycemic damage in vitro. IGF-I and IGF-II (3-100 ng/ml) each prevented glucose deprivation-induced neuronal damage in a dose-dependent manner in rat hippocampal and septal cell cultures. High concentrations of insulin (greater than 1 microgram/ml) also protected neurons against hypoglycemic damage. Epidermal growth factor did not protect against hypoglycemic damage. Both IGFs and insulin were effective when administered 24 hr before or immediately following the onset of glucose deprivation. Direct measurements of intraneuronal calcium levels and manipulations of calcium influx demonstrated that calcium influx and sustained elevations in intraneuronal calcium levels mediated the hypoglycemic damage. IGF-I and IGF-II each prevented the hypoglycemia-induced elevations of intraneuronal free calcium. Studies with excitatory amino acid receptor antagonists and calcium channel blockers indicated that NMDA receptors did, and L-type calcium channels did not, play a major role in hypoglycemic damage. Taken together, these findings indicate that IGFs can stabilize neuronal calcium homeostasis and thereby protect against hypoglycemic damage.


Functional assay of a putative Drosophila sodium channel gene in homozygous deficiency neurons. Using voltage-clamp techniques, we have examined embryonic sodium currents in neurons deficient for a gene located at 60E5/6 that shares extensive amino acid similarity with vertebrate sodium channel genes. These neurons expressed sodium currents similar to wildtype, supporting the hypothesis that para, and not the gene at 60E5/6, is the primary sodium channel gene expressed in embryonic neurons. A simple marking procedure allowing positive identification of the genotypes of cultured Drosophila embryos obtained from heterozygous parents was used to recognize cultures homozygous for deficiencies. The morphological development of both neurons and myotubes in these cultures was similar to wildtype, making it feasible to compare the properties of normal diploid cells and cells completely lacking a putative sodium channel gene.


A new genus of Metadilepididae (Cestoda: Cyclophyllidea) parasitic in Terpsiphone rufiventer (Aves: Muscicapidae) from the Ivory Coast. Pseudadelphoscolex eburnensis, a new genus and species of metadilepidid Cyclophyllidea parasitic in the red-bellied paradise flycatcher, Terpsiphone rufiventer, from the Ivory Coast, is described. The new species is characterized by davaineidlike rostellar hooks, absence of a rostellar pouch, a huge cirrus pouch in gravid proglottids, a bilobed uterus that becomes progressively reticular, absence of a paruterine organ, and eggs with an internal coat forming a crescentic protuberance outside the embryophore. The presence of a single row of rostellar hooks together with the lack of spines on the sucker and the structure and position of the uterus exclude this new material from Davaineidae. It cannot be placed in Dilepididae due to the lack of a rostellar pouch or in Paruterinidae because of the lack of a paruterine organ. The position of the excretory ducts in relation to the genital pores and the alternance of these pores are the main characters used to exclude this new species from the known genera of Metadilepididae. The diversity of forms of Metadilepididae in intertropical terrestrial birds is increased, and the validity of this taxon is strengthened.


Immunocytochemical detection of herpes viruses in oral smears of HIV-infected patients. Cytologic smears (CS) were taken from the lateral border of the tongue of HIV-seropositive patients (HIV+) (n = 39) and of seronegative controls (HIV-) (n = 19) and examined by immunocytochemistry (APAAP) and in situ hybridization (ISH) (biotinylated DNA probes) for the presence of viral antigens/DNA of EBV and CMV. While none of the HIV controls showed positive results for EBV antigen, 61% (APAAP) resp. 79% (ISH) of oral epithelial cells in the group of HIV+ patients were EBV-positive. While all CS taken from areas with the clinical diagnosis of hairy leukoplakia (HL) were EBV positive (APAAP and/or ISH), the detection of EBV in CS from uninvolved oral mucosa seemed to be associated with the later development of HL. In the group of HIV+ patients the detection rate for CMV was about five times (APAAP) resp. three times (ISH) higher than in HIV- persons. This non-invasive technique seems to be a valuable tool to screen for viral antigens/genomes.


Salivary gland 99mTc-scintigraphy: a grading scale and correlation with major salivary gland flow rates. Sequential salivary gland scintigraphy with 99mTc-technetium pertechnetate (Tc-99) is a safe, minimally invasive test for study of major salivary glands. However, its relationship to salivary function has not been investigated in detail. We have investigated the relationship between major salivary gland flow rates and Tc-99 scans and developed a new rating scale using scans of a control group with normal salivary function. Salivary flow rates and Tc-99 scans were obtained from healthy, non-medicated subjects (n = 33) and from xerostomic patients (n = 22). There were significant differences between the groups for salivary flow rates and Tc-99 ratings. Significant correlations were found between salivary flow rates and Tc-99 ratings in the control and xerostomic groups. The Tc-99 rating scale proved reliable in assessing salivary dysfunction, and showed a high inter-examiner correlation. These results demonstrate the usefulness of salivary gland scintigraphy in assessing major salivary gland flow rates and the utility of a new rating scale.


Heterologous tissue elements in melanotic neuroectodermal tumor of infancy. Two cases of melanotic neuroectodermal tumor of infancy (MNTI) contained highly cellular stromal areas consisting of spindle cells exhibiting mitotic activity. In one case, single spindle cells exhibited the same immunohistochemical profile as tumor cells forming part of the epithelial component. In the other case woven bone was formed in a dense fibroblastic stroma. These tumor parts were judged to be heterologous tissue elements that also may be observed in other kinds of neuroectodermal tumors and that reflect the potential of the neural crest to differentiate into various mesenchymal tissue types.


Platelet 3H-imipramine uptake receptor density and serum serotonin levels in patients with fibromyalgia/fibrositis syndrome. The density of serotonin reuptake receptors on peripheral platelets from 22 patients with primary fibromyalgia syndrome (FS) and the serum serotonin concentrations in 9 patients with FS were compared with those of matched healthy controls. The mean serum serotonin concentration was lower (p = 0.01) in FS than in controls, while the binding of 3H-imipramine was higher (p = 0.035) and normalized with treatment using a combination of ibuprofen and alprazolam. Improvement in selected clinical measures of FS disease activity during treatment correlated with the change in platelet 3H-imipramine binding. These findings support the proposed hypothesis of aberrant pain perception in FS resulting from a deficiency of serotonin.


Ultrasonically guided percutaneous fine needle aspiration biopsy of the hepatic and pancreatic focal lesions: accuracy of cytology in the diagnosis of malignancy. Ultrasonically guided percutaneous fine-needle aspiration biopsies were carried out on 153 patients with focal liver and pancreatic lesions, and were subsequently evaluated cytologically. A correct diagnosis of malignancy was made in 66 of 74 patients with proven hepatic malignancy, and in 38 of 41 patients with proven pancreatic malignancy, showing an overall accuracy of 92% and 94%, respectively. The specificity of the procedure was 100%. Ultrasonically guided fine-needle aspiration biopsy followed by cytological examination appears indispensable in diagnosis and differentiation between benign and malignant hepatic and pancreatic focal lesions.


Three patterns of mitochondrial DNA nucleotide divergence in the meadow vole, Microtus pennsylvanicus. The DNA sequence was determined for the cytochrome c oxidase II (COII), tRNALys, and ATPase 8 genes from the mitochondrial genome of the meadow vole, Microtus pennsylvanicus. When compared to other rodents, three different patterns of evolutionary divergence were found. Nucleotide variation in tRNALys is concentrated in the T psi C loop. Nucleotide variation in the COII gene in three genera of rodents (Microtus, Mus, Rattus) consists predominantly of transitions in the third base positions of codons. The predicted amino acid sequence in highly conserved (greater than 92% similarity). Analysis of the ATPase 8 gene among four genera (Microtus, Cricetulus, Mus, Rattus) revealed more detectable transversions than transitions, many fixed first and second position mutations, and considerable amino acid divergence. The rate of nucleotide substitution at nonsynonymous sites in the ATPase 8 gene is 10 times the rate in the COII gene. In contrast, the estimated absolute mutation rate as determined by analysis of nucleotide substitutions at fourfold degenerate sites probably is the same for the two genes. The primary sequences of the ATPase 8 and COII peptides are constrained differently, but each peptide is conserved in terms of predicted secondary-level configuration.


Multistage carcinogenesis: population-based model for colon cancer. Recent laboratory work and previous models suggest that multiple mutations are associated with the development of colon cancer. To estimate the number of mutations required for colon carcinogenesis, we used likelihood analysis to obtain the best fit between mathematical models postulating different numbers of rate-limiting events and data on incidence rates of colon cancer in two human populations--the general population of Birmingham, England, from 1968 to 1972 and patients with familial adenomatous polyposis (FAP) diagnosed at Saint Mark's Hospital, London, England, between 1925 and 1965. The Armitage-Doll model and two- and three-mutation models that explicitly incorporated cell proliferation kinetics were used. When cell kinetics were considered, models postulating either two or three rate-limiting events described the incidence rates of colon cancer equally well in both human populations. A comparison of the incidence rate of colon cancer in the general population with that in patients with polyposis suggests that a mutation at the FAP gene locus is not one of the rate-limiting events in colon carcinogenesis. Compared with the two-mutation model, the three-mutation model was more consistent with the number of mutations reported to date in colon cancer and with mutation rates measured in the laboratory. A mutation at the FAP locus may not be a rate-limiting step but may act indirectly by stimulating the proliferation of stem cells. Thus, the development of colon cancer in patients with FAP does not appear to fit the retinoblastoma paradigm.


[Effect of crocidolite fibers on the cathepsin B-like enzyme activity in HL-60 cells]. In a previous study, we found that crocidolite (an asbestos fiber) had an inhibitory effect on the differentiation process of HL-60 cells induced by dimethyl sulfoxide (DMSO). Here we describe the cathepsin B-like enzyme HL-60 cells and the changes of its activity during cell differentiation with or without crocidolite treatment. The cathepsin B-like enzyme in HL-60 cell extracts had almost the same characteristics and the already known cathepsin B as for the pH optima and the effects of proteinase inhibitors. The cathepsin B-like enzyme activity increased according to the cell differentiation induced by DMSO, however, its activity was depressed by crocidolite treatment.


Length of stay, patient severity and treatment outcome: sample data from the field of alcoholism. Lengths of stay (LOS) have been markedly reduced since the institution of diagnosis-related groups (DRGs). To determine whether such reductions represent increased efficiency or undertreatment, however, requires that LOS be examined in relation to (1) severity of patient's impairment and (2) treatment outcome. Accordingly, a retrospective analysis was conducted using a data set in which initial severity assessments and 6-month outcome results were available for 126 male veterans treated for alcohol dependence. Greater improvement was found in patients with less severe impairment, and in such patients longer periods of treatment resulted in better outcomes than shorter periods of the same treatment.


Metachronous second primary malignant fibrous histiocytoma in two skeletal muscles. The first recorded case of a metachronous second primary malignant fibrous histiocytoma (MFH) of soft tissue is presented. The patient, who has been followed every two months since the treatment of his buttock sarcoma by neoadjuvant therapy, is free of disease 24 months later. The clinical presentations, different histologies, and DNA contents of these two MFHs are consistent with metachronous primary sarcomas. The literature on second primary neoplasms is discussed.


A potent and selective non-peptide antagonist of the neurokinin A (NK2) receptor. SR 48968 is a potent and selective non-peptide antagonist of the neurokinin A (NK2) receptor. SR 48968 selectively inhibited neurokinin A binding to its receptor and was a competitive antagonist of neurokinin A-mediated contraction of different isolated smooth muscle preparations from various species including human. In vivo, the compound inhibited the bronchoconstriction induced by neurokinin A in guinea pigs. SR 48968 can be used to study the physiological or pathological role of neurokinin A and may be useful in the treatment of neurokinin A-dependent pathology.


Analysis of responses to endothelins in isolated porcine blood vessels by using a novel endothelin antagonist, BQ-153. We examined the effects of a novel ETA-selective endothelin (ET) antagonist, BQ-153, on vascular responses to ET-1 and ET-3 in isolated porcine coronary and pulmonary blood vessels, to clarify the roles of ET receptor subtypes in the regulation of vascular smooth muscle tension. With endothelium-denuded vascular tissues, the concentration-contraction curve (CCC) for ET-1 appeared as a single sigmoidal shape for all types of tissue. The CCC for ET-1 was antagonized by BQ-153 (2 and 10 microM) in all tissues, but part of the contraction was resistant. The CCC for ET-3 usually consisted of two different phases with higher (first phase) and lower (second phase) sensitivities to the peptide. Only the second phase of CCC for ET-3 was completely inhibited by BQ-153 (2 microM) in all tissues, while the first phase was resistant. The BQ-153-resistant contractile phases of ET-1 and ET-3-induced vasoconstriction appeared to have similar sensitivity in all tissues, and the contractile activity varied with each type of tissue. With endothelium-intact materials, the potencies of ET-1 and ET-3 for endothelium-dependent vasorelaxation in pulmonary artery were almost equivalent. BQ-153 (10 microM) did not inhibit ET-induced vasorelaxation. These results indicate that ET-induced vasoconstriction is mediated not only through ETA but also through ETnonA (probably ETB), and that the relative proportions of the ET-receptor subtypes mediating contractions vary in different vascular areas. In addition, results showed that ET-induced endothelium-dependent vasorelaxation is mediated through ETB.


The George B. Koelle symposium on the cholinergic synapse. The George B. Koelle Symposium on the Cholinergic Synapse described the early development of the importance of ACh as a transmitter at both cholinergic synapses of the CNS, ganglion and neuromuscular junction. While a great deal is known about the function of cholinergic transmission at the neuromuscular junction, the integrated role of cholinergic, nicotinic and muscarinic receptors in the overall process of CNS functions, i.e., behavior, motor control, abstract thinking, memory and speech remains as a challenge for future investigation. The architecture of the cholinergic synapse appears to be a dynamic process involving ARIA, Agrin and the various forms of ACh esterase. The regulation of gene expression and site directed localization of postsynaptic cholinergic receptor proteins during the life cycle involves the dynamic interactions of these agents with the postsynaptic membrane and postsynaptic gene express. The last two papers at the symposium dealt with the chemistry of the nicotinic receptor regulated channel involved in ACh binding and the consequent cationic channel conductional changes.


Regulation of adrenal atrial natriuretic hormone receptor subtypes. Regulation of atrial natriuretic hormone (ANH) receptor binding and aldosterone suppression was studied in isolated adrenal glomerulosa cells from rats fed a high-salt (HS) or low-salt (LS) diet for 3 days. In plasma of HS rats, aldosterone levels were 5 times lower and immunoreactive ANH two times higher than in LS rats. Competitive binding studies showed the same affinity for human atrial natriuretic hormone (hANH) in both pools of cells, but receptor density was 50% higher on LS cells. A linear ANH analog that binds to non-guanylate-cyclase-coupled receptors did not show increased binding to LS cells. Cyclic GMP production in response to hANH was identical in both groups. The aldosterone-inhibitory effect of hANH on both groups of basal and angiotensin II-stimulated cells was also identical. Thus a short-term high-salt diet causes decreased density of ANH receptors in glomerulosa cells without changing biological activity of ANH. These results suggest that dietary salt content changes the number of ANH receptors and that non-guanylate-cyclase-coupled receptors contain at least two classes of receptors.


Effect of acute intravenous administration of delta-9-tetrahydrocannabinol on the episodic secretion of immunoassayable growth hormone in the rat. Blood samples from unrestrained, unanesthetized, male rats (300-350 g) were obtained every 15 min. for 9 consecutive hrs. (1000-1900 h). Each rat received, intravenously, a vehicle injection (controls) or a 2.0 mg/kg dose of delta-9-tetrahydrocannabinol (THC) at 1300 h to determine the effect of this drug on the spontaneous episodic secretion of plasma immunoassayable rat growth hormone (rGH). Acute administration of THC suppressed the secretion of rGH, as is evident from mean plasma level (p less than .01), peak height (p less than .02), and integrated peak amplitude (p less than .02) analyses. Episodic secretion was inhibited in all animals (n = 7) receiving THC. Although further investigation is needed to define clearly the physiological mechanisms involved in this response, these data indicate that THC can inhibit the hypothalamic-pituitary control of normal episodic growth hormone secretion in the rat.


Arachidonic acid inhibits Cl secretion in cultures of dog tracheal epithelium. We studied the effects of arachidonic acid (AA) on Cl secretion across primary cultures of dog tracheal epithelium. Cell sheets showed mean values for baseline short-circuit current (Isc) and transepithelial resistance of 33.8 muA/cm2 and 360 omega.cm2 (n = 44). AA (5 x 10(-5) M) added to both sides increased Isc by 27.8 +/- 5.2 muA/cm2 (mean +/- SE, n = 8), and elevated intracellular cAMP levels. In the presence of 5 x 10(-6) M of both indomethacin (INDO) and nordihydroguaiaretic acid (NDGA) (inhibitors of cyclooxygenase and lipoxygenase, respectively), AA reduced Isc by 4.4 +/- 0.6 muA/cm2 (n = 10) without changing cAMP. Both INDO and NDGA were necessary to abolish the Isc increase in response to AA. The effects of AA on Isc were unaffected by amiloride. In the presence of INDO and NDGA, isoproterenol (ISO) raised cAMP and increased Isc by 27.6 +/- 4.3 (transient) and 12.8 +/- 3.2 muA/cm2 (sustained) (n = 9). With AA present as well as INDO and NDGA, the transient and sustained responses to ISO were significantly reduced to 13.2 +/- 2.4 and 3.9 +/- 0.8 muA/cm2 (n = 10), respectively; the increase in cAMP was unaltered. AA approximately halved baseline efflux of 125I from confluent cell sheets in high K medium and reduced the isoproterenol-induced increase in efflux to 20% of control. These data are consistent with the reported inhibitory effect of AA on apical membrane chloride channels.


Theory of paramagnetic contrast agents in liposome systems. We develop a theoretical description of nuclear spin relaxation mediated by MRI contrast agents and transport processes in liposome systems. Such systems compartmentalize the physical space such that paramagnetic contrast agents, which enhance relaxation, are trapped in some subvolume. Due to diffusive transport across compartmental barriers, i.e., across liposome membranes, nuclear spins in the whole volume exhibit fast relaxation. The description developed is based on the diffusion-Bloch equations for the nuclear magnetization with appropriate boundary and continuity conditions. From this set of equations a new inhomogeneous differential equation for the local relaxation times is derived. For simple geometries of compartmentalized spaces the equation can be solved analytically. A simple formula for average relaxation times in liposome systems is presented. The resulting relaxation times agree well with observations.


Radial scanning technique for volume selective 31P spectroscopy. An interlaced radial scanning method that is ideally suited for 31P spectroscopy with short T2 components and a wide spectral range is presented. The proposed method, which uses an additional radial gradient and radial scans in the k-space, minimizes T2 decay during the selection time and also optimizes the volume selectivity in a given gradient field strength. Simulation and experimental results with a short selection time of 2 ms demonstrate that the proposed method is suitable for volume selective 31P spectroscopy.


The integrated academic information management system at Columbia-Presbyterian Medical Center. Over the past seven years, Columbia-Presbyterian Medical Center has been planning and implementing an integrated academic information management system. Accomplishments to date include establishing an institutional information architecture, installing a campus-wide network of workstations, recruiting the staff needed to develop and implement the system, and developing various applications. This paper presents the rationale and steps involved in these accomplishments, as well as data on use of the system so far.


Iron-dextran as a magnetic susceptibility contrast agent: flow-related contrast effects in the T2-weighted spin-echo MRI of normal rat and cat brain. Iron-dextran (1 mmol Fe/kg) was used as an intravascular, paramagnetic contrast agent in rat and cat brain in conventional spin-echo T2-weighted (TR 2800/TE 100) 1H magnetic resonance imaging. The resulting images displayed differential decreases (30-50%) in intensity whose pattern was similar to that obtained with the superparamagnetic particulate iron oxide AMI-25 (0.18 mmol Fe/kg). Postcontrast images displayed improved anatomic detail, and contrast effects were observed to be greater in cortical and subcortical gray matter than in adjacent white matter. Intravenous injection of acetazolamide after administration of iron-dextran caused a small additional decrease in image intensity. Measurement of whole blood and plasma at 5 min postinjection of either contrast agent revealed significant increases in their volume magnetic susceptibilities. The contrast effect appears to be related to magnetic susceptibility changes brought about by the iron-dextran; it has both blood volume and blood flow components. The static model of magnetic susceptibility effects in brain capillaries is modified to include bolus flow of erythrocytes, providing a mechanism for the observed flow effects.


A hybrid bird cage resonator for sodium observation at 4.7 T. A bird cage resonator operating at 52.9 MHz is described. The particularity of the presented design is due to fixed capacitors between conductors. Tuning is performed by adjusting a self-capacitance system without breaking the coil symmetry. This structure denoted as "hybrid" is suitable for biological lossy samples.


Proton nuclear magnetic resonance studies on water structure in peritumoral edematous brain tissue. Spin-lattice relaxation times (T1) of water protons and cross-relaxation times (TIS) between irradiated protein and water protons were measured to study the water structure in peritumoral edematous brain tissue of rats. Despite small changes in T1, water, and electrolyte contents, TIS values of water protons were significantly reduced in peritumoral edematous brain tissue when compared to those of the controls. Results indicate that the water structure in brain tissues may become altered at an early stage of edemic formation without causing any significant changes in cellular hydration. TIS might serve as a sensitive parameter for studying the water structure in a variety of tissues, such as in edematous brain tissue.


Effect of dietary fats on erythrocyte membrane lipid composition and membrane-bound enzyme activities. Four different oil-based diets were used in a feeding study involving rats to assess the relationship between the fatty acid composition of the dietary fat and its influence on erythrocyte membrane (EM) lipid composition and the activities of membrane-bound enzymes. Nutritionally adequate diets containing 20% groundnut (GNO), coconut (CO), safflower (SO), or mustard oil (MO) were fed to weanling CFY rats for 4 months. EMs were analyzed for total cholesterol, phospholipids, fatty acid profiles, and sialic acid content. Activities of membrane-bound enzymes such as Na+, K(+)-adenosine triphosphatase (ATPase), Mg(2+)-ATPase, Ca2+, Mg(2+)-ATPase, and acetylcholinesterase were also assayed. The activities of all membrane-bound enzymes, except Mg(2+)-ATPase, and sialic acid content were higher in the MO-fed group than in the rest of the groups. Ca2+, Mg(2+)-ATPase activity was distinctly lower in the SO-fed group than in the other groups. Cholesterol to phospholipid molar ratio was similar in all the groups. However, SO- and MO-fed groups displayed an increased cholesterol content and a higher degree of unsaturation in the membrane fatty acid composition. The higher membrane fatty acid unsaturation in the SO-fed group was principally due to linoleic (18:2) and arachidonic (20:4) acids, while in the MO-fed group it was mainly due to oleic (18:1), eicosenoic (20:1), erucic (22:1), and linoleic (18:2) acids. These results suggest a relationship between the quality of dietary fat, EM fatty acyl composition, and the activities of membrane-bound enzymes.


Reduction of erythrocyte (Na(+)-K+) ATPase activities in non-insulin-dependent diabetic patients with hyperkalemia. To elucidate the mechanism of hyperkalemia in diabetic patients without renal failure, we investigated (Na(+)-K+) adenosine triphosphatase (ATPase) activity in erythrocyte membrane, erythrocyte Na+ and K+ content, and plasma endogenous digitalis-like substance in control subjects (n = 16) and non-insulin-dependent diabetes mellitus (NIDDM) patients (n = 62). NIDDM patients were divided into normokalemic patients (NKDM, n = 48) and hyperkalemic patients (HKDM, n = 14). There was no difference in plasma glucose or hemoglobin A1c (HbA1c) levels, plasma renin activity (PRA), and plasma aldosterone concentrations (PAC) between NKDM and HKDM patients. (Na(+)-K+)ATPase activities in NIDDM patients were significantly reduced compared with those in control subjects (0.336 +/- 0.016 mumol-inorganic phosphate [Pi]/mg protein/h, mean +/- SEM, P less than .05), and (Na(+)-K+)ATPase activities in HKDM patients (0.243 +/- 0.015 mumol Pi/mg protein/h) were significantly reduced compared with those in NKDM patients (0.295 +/- 0.008 mumol Pi/mg protein/h, P less than .01). Plasma K+ content had a significant negative correlation with (Na(+)-K+)ATPase activity in diabetic patients (r = -.365, P less than .01). Erythrocyte Na+ content had a significant negative correlation with (Na(+)-K+)ATPase activity in control subjects (r = -.619, P less than .05). There was no difference in plasma endogenous digitalis-like substance among the three groups. (Na(+)-K+)ATPase activity was not significantly correlated with plasma endogenous digitalis-like substance in control subjects and diabetic patients. These findings suggest that the reduction of (Na(+)-K+)ATPase activity, which was not related to plasma digitalis-like substance, may be partly responsible for hyperkalemia in diabetic patients.


Antibody response to cytomegalovirus (CMV) polypeptides in liver transplant recipients with CMV hepatitis. Immunoblotting (IB) was used to detect the presence of serum antibody against each individual CMV structural polypeptide and the major nonstructural antigen during CMV hepatitis in 12 orthotopic liver transplant recipients to evaluate the diagnostic utility of this technique. The basic phosphoprotein p150 primarily, and to a much lesser extent p65 (lower matrix protein) and p52 (nonstructural DNA-binding protein) were the most recognized antigens by both IgG and IgM class antibodies. Collectively, IgM antibodies were detected to p150 in 9 of 12 (75%) patients and were detected before (2 cases), at the same time (1 case), or after (6 cases) detection of virus in cell cultures. IB was equal to indirect immunofluorescence (IIF) and enzyme immune assay (EIA) for the detection of IgG and superior to EIA for IgM class antibodies to CMV in OLT patients. Our results indicate that the p150 phosphoroprotein is an essential component of serologic assays, especially for the detection of IgM antibodies to CMV.


Combined vaccination of cattle against FMD and rabies. Three groups of crossbred calves were vaccinated with FMD vaccine only, combined FMD + rabies vaccine and rabies vaccine alone. Efficacy of the vaccines was determined by serum antibody assay at different intervals postvaccination. The results of the study indicated that the immune response of animals to a single inoculation of FMD vaccine only as well as combined FMD + rabies vaccine was unsatisfactory due to maternally derived antibodies to FMD virus antigen. However two inoculations elicited a satisfactory antibody response to FMD virus antigens in both group of animals. Rabies antigen alone as well as combined FMD + rabies antigen induced satisfactory serum antibody titres to rabies antigen. There was no significantly different serological responses in animal administered FMD vaccine only, rabies vaccine only or combined FMD + rabies vaccine.


IgG antibodies to human herpesvirus-6 (HHV-6) in Italian people. Sera from a sample of healthy Italian people were tested in an indirect immunofluorescence assay (IFA) for reactivity to a Human Herpesvirus-6 (HHV-6) strain called CV, isolated from a baby with exanthem subitum (Portolani et al., 1990). Seropositivity values of 83.78%, 92.68% and 63.64% were found in subjects aged 3 months-6 years, 6-18 years and over 18 years respectively. Sera from cordal blood, sera from subjects with evidence of active infection by Cytomegalovirus (CMV) or by Epstein-Barr virus (EBV), sera from seropositive adults to Human Immunodeficiency Virus type 1 (HIV) were also investigated for antibodies to the same HHV-6 strain. Values of antibody incidence and antibody content to HHV-6 in these groups of sera were generally higher than in the other groups. HHV-6 reinfections of both endogenous and exogenous origin and antibody cross-reactivity were considered among the reasons of this increase. HHV-6 seropositivity values in healthy Italian people and in people from different countries were also discussed in the light of the antigenic characteristics of the HHV-6 strains used and of the different test conditions.


The human toxicity of marijuana.

The human toxicity of marijuana. The pathophysiological effects of marijuana smoke and its constituent cannabinoids were reported first from in-vitro and in-vivo experimental studies. Marijuana smoke is mutagenic in the Ames test and in tissue culture and cannabinoids inhibit biosynthesis of macromolecules. In animals, marijuana or delta 9-tetrahydrocannabinol (THC), the intoxicating material it contains, produces symptoms of neurobehavioural toxicity, disrupts all phases of gonadal or reproductive function, and is fetotoxic. Smoking marijuana can lead to symptoms of airway obstruction as well as squamous metaplasia. Clinical manifestations of pathophysiology due to marijuana smoking are now being reported. These include: long-term impairment of memory in adolescents; prolonged impairment of psychomotor performance; a sixfold increase in the incidence of schizophrenia; cancer of mouth, jaw, tongue and lung in 19-30 year olds; fetotoxicity; and non-lymphoblastic leukemia in children of marijuana-smoking mothers.


Advances in cerebral ischemia: experimental approaches. Drugs that dissolve clots, such as streptokinase and rTPA, and drugs that promote vasodilation are undergoing clinical testing for the treatment of hyperacute stroke, but an adjuvant therapy that either prolongs temporal thresholds before irreversible injury occurs or actually protects the brain from ischemia would transform these trials. Mild hypothermia, either intraischemically or at the onset of reperfusion, provides us with a gold standard for cytoprotection against which new pharmacologic strategies can be measured. The cytoprotective effects of the voltage-sensitive calcium channel blockers and the NMDA antagonists have been relatively less compelling than more recent findings with non-NMDA or AMPA antagonists. Their ability to inhibit SINN or reduce neocortical infarction is remarkable. Future randomized clinical trials for both resuscitated cardiac arrest victims and patients sustaining embolic stroke are predicted by this major advance in the field of stroke medicine.


A framework for assessing the effectiveness of disease and injury prevention. This report presents background information for a series of MMWR articles on evaluating the effectiveness of disease and injury prevention strategies, describes issues surrounding the assessment of effectiveness, and provides an overview of methods used in such assessments.


Surveillance for epidemic cholera in the Americas: an assessment. In January 1991, epidemic cholera appeared in Peru and quickly spread to many other Latin American countries. Because reporting of cholera cases was often delayed in some areas, the scope of the epidemic was unclear. An assessment of the conduct of surveillance for cholera in several countries identified some recurrent problems involving surveillance case definitions, laboratory surveillance, surveillance methods, national coordination, and data management. A key conclusion is that a simple, well-communicated cholera surveillance system in place during an epidemic will facilitate prevention and treatment efforts. We recommend the following measures: a) simplify case definitions for cholera; b) focus on laboratory surveillance of patients with diarrhea primarily in the initial stage of the epidemic; c) use predominantly the "suspect" case definition when the number of "confirmed" cases rises; d) transmit weekly the numbers of cases, hospitalized patients, and deaths to regional and central levels; e) analyze data frequently and distribute a weekly or biweekly summary; and f) report the number of cholera cases promptly to the World Health Organization.


Nucleotide sequence and structure of the Klebsiella pneumoniae pqq operon. A 6940 bp Klebsiella pneumoniae chromosomal DNA fragment, containing genes involved in pyrroloquinoline quinone (PQQ) biosynthesis, was sequenced. Six open reading frames, pqqA, pqqB, pqqC, pqqD, pqqE and pqqF were identified in the pqq operon, which coded for polypeptides of 2764 (23 amino acids), 33,464, 28,986, 10,436, 42,881 and 83,616 Da, respectively. The transcription startpoint was mapped by primer extension analysis, upstream of pqqA, and promoter boxes could be identified. The gene products of pqqB, pqqC, pqqE and pqqF were detected in maxi-cells and the molecular weights of the proteins corresponded with the molecular weights deduced from the nucleotide sequence. The gene products of pqqA, pqqB, pqqC, pqqD and pqqE show 49%-64% identity in amino acid sequence with those of pqqIV, pqqV, pqqI, pqqII and pqqIII respectively in the cloned pqq cluster of Acinetobacter calcoaceticus. The 84 kDa protein encoded by pqqF, which is not present in the cloned pqq cluster of A. calcoaceticus but which is essential for PQQ biosynthesis in K. pneumoniae and Escherichia coli, seems to belong to a family of proteases.


The Tn10-encoded Tet repressor blocks early but not late steps of assembly of the RNA polymerase II initiation complex in vivo. We have studied the effect of the Tn10-encoded Tet repressor on expression from 13 cauliflower mosaic virus (CaMV) 35S promoter derivatives that contain a tet operator sequence in various positions downstream of the TATAbox. When the operator sequence was inserted less than 33 bp away from the TATAbox (position +9 with respect to the transcription start site), the repressor interfered with transcription, whereas increasing the distance to 35 bp (position +11) abolished repression. This result indicates that initiation of transcription from the CaMV 35S promoter occurs in at least two different steps: (1) binding of transcription factors, involving sequences extending to position +9; this step can be inhibited by binding of the Tet repressor protein; and (2) initiation of transcription from this complex, which is not affected by the repressor protein. We suggest that the Tet repressor can be used to investigate whether transcription conditions in vitro truly reflect the in vivo situation.


Characterization of ultra-high affinity monoclonal antibodies with a dimeric, symmetrical antigen: inhibition of the receptor recognition site of nerve growth factor. We generated a family of ultra-high affinity monoclonal antibodies (MAb) which inhibit competitively the binding of nerve growth factor (NGF) to its receptor. Preliminary experiments indicated that the dissociation constants (Kd) of some of the MAb:NGF complexes were substantially less than 0.1 nM. Conventional methods, such as ELISA and radioimmunoassays (RIA), were not sufficiently sensitive to measure the Kds of these MAb. Therefore, experimental conditions were developed to determine binding constants for these very high affinity MAb. The experiments establish that the Kds for our anti-NGF MAb range from 2.6 nM to 39 fM. Additionally, the inhibition of NGF binding to NGF-receptor by MAb is fully consistent with a purely competitive model but is not consistent with a model allowing the formation of a ternary complex of NGF, MAb, and NGF-receptor. One MAb, M4, immunoprecipitates NGF indicating interaction between each protomer of the NGF dimer and individual MAb molecules. We also evaluated the effects of mild denaturing conditions on the binding and biological activity of NGF and on recognition by the MAbs. Guanidine HCl or heat treatment of NGF resulted in only small, but significant, changes in binding or biological activity, in parallel with changes in recognition by the MAbs. However, binding, biological activity, and recognition by six of seven MAbs were completely eliminated by beta-mercaptoethanol reduction. Thus, our results are consistent with the MAbs interacting with the receptor recognition site on the surface of the NGF molecule. The high affinity MAbs will serve as sensitive probes of structural elements of NGF responsible for binding and biological activity.


[Intrauterine pericardial effusion. Early symptom of a primary symptomatic congenital cytomegaly]. We report of a fetus who was ultrasonographically shown to have growth retardation, oligohydramnios and a pericardial effusion without other components of a hydrops fetalis at 28 weeks' gestation. At 29 weeks' gestation the child was born by cesarean section of pathological CTG. A congenital cytomegaly was diagnosed. The etiological role of the infection for the development of the pericardial effusion is discussed.


[Hepatitis C virus (HCV). Low infection rate in premature and full-term neonates following multiple transfusions]. Nearly all cases of non-A, non-B post-transfusion hepatitis are caused by hepatitis C virus (HCV). Data for HCV infection in childhood are limited. 262 Children who received poly-transfusion between 1979 and 1983 were re-examined at a mean age of 3.5 years for HCV infection using an first-generation enzyme immunoassay to detect anti-HCV antibodies. 14 of 262 children had positive anti-HCV titers (5.3%), 7 of them showed border line results. In further two patients HCV infection was suspected by clinical means, but initial serology was not available. 6.5 years later, 15 of these 16 children were re-examined at a mean age of 9.8 years. All had normal liver enzymes and positive anti-HCV serology was shown in 3 patients (1%). This study demonstrates a low incidence of HCV infection after poly-transfusion during neonatal age. The rate of HCV infection may be even higher, if other more specific tests for HCV serology or PCR will be routinely available in the near future.


The coordination of posture and voluntary movement in patients with cerebellar dysfunction. Postural adjustments associated with the task of rising on tiptoes were investigated in a reaction time paradigm in 10 normal subjects and 18 patients with cerebellar disorders. Cerebellar dysfunction was due to either degenerative cerebellar disease, tumor, or ischemia. Displacements of the center of foot pressure (CFP) were recorded. The task, accomplished by the triceps surae muscle (executional activity, mean latency of 411 ms), is mechanically effective only if the center of gravity has been shifted forward in advance. To this effect, a phasic burst of preparatory EMG activity in the tibialis anterior normally occurs at a mean latency of 163 ms, shifting the center of gravity forward. Shortly thereafter, activity of the quadriceps femoris (175 ms) extends the knee and aids the forward shift of the center of gravity. Different aspects of this motor sequence were disturbed in individual patients: Latencies of preparatory and executional activity were uncorrelated in 15 of the 18 patients. Executional (n = 16) or preparatory (n = 13) EMG activity was tonic instead of phasic. Latencies of either preparatory or executional EMG activities or both were prolonged (n = 10). The time interval between motor preparation and execution was increased (n = 9). The trial-to-trial variability of biomechanical parameters and EMG latency was increased. Preparatory EMG activity in the quadriceps was entirely missing (n = 9), resulting in knee bending at the unsuccessful attempt to rise on tiptoes. Patients who were most severely affected had no preparatory activity at all (n = 2), and therefore were unable to perform the task.(ABSTRACT TRUNCATED AT 250 WORDS)


A congenital myasthenic syndrome refractory to acetylcholinesterase inhibitors. We studied 4 siblings (3 men and 1 woman), ages 22 to 43 years, with congenital ptosis, external ophthalmoplegia, proximal muscle weakness and fatigability unresponsive to acetylcholinesterase (AChE) inhibitors. Repetitive nerve stimulation showed a significant compound muscle action potential (CMAP) area decrement at 2 or 3 Hz. Nerve conduction studies and concentric needle electromyography were normal, and repetitive CMAPs to single nerve stimulation were not observed. Voluntary single fiber electromyography (SFEMG) showed increased jitter and blocking. Assessment of individual end-plates using SFEMG with intramuscular axonal microstimulation showed no uniform relationship between jitter and the rate of stimulation, consistent with a postsynaptic defect of neuromuscular transmission. Edrophonium eliminated the decremental response to repetitive nerve stimulation, but caused no significant clinical improvement, suggesting an additional mechanism for weakness in these patients.


In vitro microelectrode study of neuromuscular transmission in a case of botulism. We performed in vitro microelectrode studies in the anconeus muscle biopsy of a 6-week-old infant intoxicated with Clostridium botulinum toxin B. The most striking abnormalities were the severe reduction of the endplate potential (EPP) quantal content and the marked variability of EPP latencies. The increased variability was often limited to a "single quantum" component of the EPP. Neither the amplitudes nor the frequencies of spontaneous miniature endplate potentials (MEEPs) were decreased. However, there was a wide range of amplitudes and frequencies of MEPPs. This unique combination of electrophysiologic findings indicates a severe presynaptic failure of neuromuscular transmission, which appears to result from an impairment of the process of synaptic vesicle release taking place after the stimulus induced influx of calcium into the motor nerve terminals.


The function of large and small nerve fibers in renal failure. Previous clinical and neurophysiological studies of uremic neuropathy have focused almost exclusively on the function of large sensory and motor axons. The sensations of heat and cold depend on the function of unmyelinated afferents and small myelinated afferents, respectively, and these sensations can be quantified using a standardized psychophysical technique. Thermal thresholds were measured in 20 patients with end-stage renal failure to determine the extent of small afferent fiber involvement and to compare this with the clinical and electrophysiological evidence of large fiber involvement. Whereas abnormalities of standard nerve conduction studies were found in 16 patients, abnormal thermal thresholds were found in only 6 patients. In the nerve conduction studies, the amplitudes of nerve potentials were reduced more than their conduction velocities, consistent with an axonopathy. This study found little evidence of significant dysfunction of small afferent fibers in end-stage renal failure and, when such changes occurred, they did not correlate with the clinical evidence of polyneuropathy. The functional sparing of axons of small diameter is consistent with the relative sparing of these axons in pathological studies.


Proximal median neuropathies: electromyographic and clinical correlation. Results of electrophysiologic and clinical findings in 17 patients with proximal median neuropathy were reviewed. The cause of neuropathy was trauma in 5 patients, overuse of the pronator teres in 3 patients, postinfectious in 2 patients, secondary to a congenital lesion in 1 patient, and undetermined in 6 patients. The neuropathy involved the main branch of the median nerve at or proximal to the pronator teres muscle (high median neuropathy) in 14 patients, and the anterior interosseous portion of the nerve in 3 patients. Electrophysiologic findings, especially needle electromyography (EMG), were more definitive than findings expected from clinical examinations. EMG and operative findings demonstrated that median nerve compression by the pronator teres produces denervation of this muscle as well as distal muscles. EMG cannot differentiate a median nerve lesion at the pronator teres from a more proximal lesion. Follow-up data were available in 7 of 10 nonsurgically managed patients, and in 6 of 7 patients with surgical decompression. Six patients in each group were either improved or normal.


Hypervitaminosis D associated with drinking milk. Vitamin D has been added to milk in the United States since the 1930s to prevent rickets. We report the unusual occurrence of eight cases of vitamin D intoxication that appear to have been caused by excessive vitamin D fortification of dairy milk. Medical records were reviewed and a dietary questionnaire was sent to eight patients who had unexplained hypervitaminosis D. Vitamin D analyses with high-performance liquid chromatography were performed on samples of the patients' serum, the dairy milk they drank, and the vitamin D concentrate added to the milk. All eight patients drank milk produced by a local dairy in amounts ranging from 1/2 to 3 cups (118 to 710 ml) daily. All had elevated serum 25-hydroxyvitamin D concentrations (mean [+/- SD], 731 +/- 434 nmol per liter [293 +/- 174 ng per milliliter]). Six of the eight patients had elevated serum vitamin D3 concentrations. Of the eight patients, seven had hypercalcemia and one had hypercalciuria but normocalcemia (mean serum calcium, 3.14 +/- 0.51 mmol per liter [12.6 +/- 2.1 mg per deciliter]). Analysis of the dairy's vitamin D-fortified milk revealed concentrations of vitamin D3 (cholecalciferol) that ranged from undetectable to as high as 232,565 IU per quart (245,840 IU per liter). An analysis of the concentrate that was used to fortify the milk, labeled as containing vitamin D2 (ergocalciferol), revealed that it contained vitamin D3. Hypervitaminosis D may result from drinking milk that is incorrectly and excessively fortified with vitamin D. Milk that is fortified with vitamin D must be carefully monitored.


The vitamin D content of fortified milk and infant formula. The fortification of milk and infant formula with vitamin D has had an important role in eliminating rickets in children and osteomalacia in adults. A recent outbreak of vitamin D intoxication caused by drinking milk fortified with excess vitamin D has led to questions about the level of vitamin D in milk from other producers. We used high-performance liquid chromatography to measure vitamin D in samples of 13 brands of milk with various fat contents and 5 brands of infant formula purchased at random from local supermarkets in five Eastern states. Only 12 (29 percent) of the 42 samples of the 13 brands of milk and none of the 10 samples of the 5 brands of infant formula contained 80 to 120 percent of the amount of vitamin D stated on the label. Twenty-six of the 42 milk samples (62 percent) contained less than 80 percent of the amount claimed on the label. No vitamin D was detected in 3 of the 14 samples of skim milk tested (lower limit of assay, 4.7 IU per quart [5.0 IU per liter]). One milk sample labeled as containing vitamin D2 (ergocalciferol) contained vitamin D3 (cholecalciferol). Seven of the 10 samples of infant formula contained more than 200 percent of the amount stated on the label; the sample with the highest concentration contained 419 percent of the stated amount. None of the samples of infant formula contained less than the amount stated. Milk and infant-formula preparations rarely contain the amount of vitamin D stated on the label and may be either underfortified or overfortified. Since both underfortification and overfortification are hazardous, better monitoring of the fortification process is needed.


A controlled trial of ganciclovir to prevent cytomegalovirus disease after heart transplantation. Because of the immunosuppression required, heart-transplant recipients frequently have complications caused by cytomegalovirus (CMV), including pneumonia, esophagitis, gastritis, and a syndrome of fever, hepatitis, and leukopenia. We undertook a controlled trial to evaluate the prophylactic administration of ganciclovir to prevent CMV-induced disease after heart transplantation. This randomized, double-blind, placebo-controlled trial was conducted at four centers. Before randomization, the patients were stratified into two groups: those who were seropositive for CMV before transplantation and those who were seronegative but who received hearts from seropositive donors. Ganciclovir was given intravenously at a dose of 5 mg per kilogram of body weight every 12 hours from postoperative day 1 through day 14, then at a dose of 6 mg per kilogram each day for 5 days per week until day 28. Among the seropositive patients, CMV illness occurred during the first 120 days after heart transplantation in 26 of 56 patients given placebo (46 percent), as compared with 5 of 56 patients treated with ganciclovir (9 percent) (P less than 0.001). Among 37 seronegative patients, CMV illness was frequent in both groups (placebo, 29 percent; ganciclovir, 35 percent; P not significant). From day 15 through day 60, the patients who took ganciclovir had significantly fewer urine cultures positive for CMV, but by day 90 there was no difference. More of the ganciclovir-treated patients had serum creatinine concentrations greater than or equal to 221 mumol per liter (2.5 mg per deciliter) (18 percent vs. 4 percent in the placebo group), but those elevations were transient. The prophylactic administration of ganciclovir after heart transplantation is safe, and in CMV-seropositive patients it reduces the incidence of CMV-induced illness.


Calcium channel characteristics conferred on the sodium channel by single mutations. The sodium channel, one of the family of structurally homologous voltage-gated ion channels, differs from other members, such as the calcium and the potassium channels, in its high selectivity for Na+. This selectivity presumably reflects a distinct structure of its ion-conducting pore. We have recently identified two clusters of predominantly negatively charged amino-acid residues, located at equivalent positions in the four internal repeats of the sodium channel as the main determinants of sensitivity to the blockers tetrodotoxin and saxitoxin. All site-directed mutations reducing net negative charge at these positions also caused a marked decrease in single-channel conductance. Thus these two amino-acid clusters probably form part of the extracellular mouth and/or the pore wall of the sodium channel. We report here the effects on ion selectivity of replacing lysine at position 1,422 in repeat III and/or alanine at position 1,714 in repeat IV of rat sodium channel II (ref. 3), each located in one of the two clusters, by glutamic acid, which occurs at the equivalent positions in calcium channels. These amino-acid substitutions, unlike other substitutions in the adjacent regions, alter ion-selection properties of the sodium channel to resemble those of calcium channels. This result indicates that lysine 1,422 and alanine 1,714 are critical in determining the ion selectivity of the sodium channel, suggesting that these residues constitute part of the selectivity filter of the channel.


Mapping antibody binding sites on protein antigens. The large surfaces of protein antigens that interact with antibody-combining sites can be determined using deuterium-exchange labelling and two-dimensional 1H nuclear magnetic resonance (NMR). This technique may also be applied to other protein-protein interactions to identify key residues that contribute to the affinity.


Characterization of calcitonin gene-related peptide (CGRP) receptors in guinea pig basilar artery. The vasomotor effects of calcitonin gene-related peptide (CGRP) analogs have been studied in circular segments of guinea pig basilar artery in vitro. Five CGRP agonists induced concentration-dependent relaxations of pre-contracted vessels with the following order of potency: alpha-rCGRP greater than or equal to beta-rCGRP greater than or equal to alpha-hCGRP greater than beta-hCGRP greater than [Tyr0]CGRP with maximum responses between 80 and 87%. The magnitude of responses to calcitonin was low (12%) but with the same potency as the CGRP analogs. hCGRP(8-37) (10(-6) M), a CGRP antagonist, induced a parallel shift of alpha-rCGRP- and alpha-hCGRP-induced relaxations but not of beta-rCGRP and beta-hCGRP. Another putative antagonist [Tyr0]CGRP28-37 (10(-6) M) had no antagonistic effect on dilator responses to the CGRP agonists. The results suggests two types of CGRP responses in the guinea pig basilar artery: alpha-CGRP induced relaxation is blocked by the antagonist hCGRP(8-37), while the equally strong dilator response to beta-CGRP is not antagonized. It is therefore possible that the guinea pig basilar artery is equipped with CGRP-1 receptors sensitive to hCGRP(8-37) and CGRP-2 receptors being sensitive to beta-CGRP but not antagonized by hCGRP(8-37).


Pattern of 2-deoxy-2-[18F]-fluro-D-glucose accumulation in liver tumours: primary, metastatic and after chemotherapy. Eight patients with liver metastases from adenocarcinoma of the colon or rectum, two with suspected hepatic metastases and one with primary hepatoma were studied with 2-deoxy-2-[18F]-fluro-D-glucose (18F-FDG) using positron emission tomography (PET). In five of the patients with metastatic tumour a second examination was performed four weeks after treatment with recombinant interleukin-2 (rIL2) and fluorouracil (5FU). In all tumours (one primary and eight metastatic) the radioactivity was seen to accumulate in a rim around each tumour with a large central area showing no uptake. In the five cases imaged after treatment with rIL2, the appearance of the tumour uptake was the same as before treatment. In the two cases of suspected but not proven metastases, no abnormal accumulation of 18F-FDG was seen.


Management of childhood lead poisoning: a survey. Published recommendations (1985) for the management of childhood lead poisoning suggest the use of ethylenediaminetetraacetic acid (EDTA) provocation testing and chelation as the mainstay of treatment for blood lead levels between 25 and 55 micrograms/dL. Since 1985 evidence has accumulated indicating that (1) levels of blood lead less than 25 micrograms/dL are detrimental to cognitive development, (2) EDTA provocation testing may result in potentially harmful shifts in the body lead burden, and (3) oral agents such as penicillamine and 2,3-dimercaptosuccinic acid are effective in reducing elevated lead levels. To determine how this evidence impacts on the management of childhood lead poisoning, the authors surveyed the lead poisoning clinics of pediatric departments in the cities estimated by the United States Public Health Service to have the largest number of children affected by lead poisoning. Thirty (70%) of 43 surveys were completed. Respondents indicated that the lowest blood lead level for which they would use a chelating agent to reduce the lead burden was as follows: 50 micrograms/dL (3%), 45 micrograms/dL (3%), 40 micrograms/dL (13%), 35 micrograms/dL (3%), 30 micrograms/dL (27%), 25 micrograms/dL (47%), and 20 micrograms/dL (3%). For all blood lead levels from 20 through 55 micrograms/dL, EDTA was the most frequently recommended chelating agent (chelation and provocation testing). Fifteen percent of responding lead clinics do not use the provocation test under any circumstances. For a child with a negative EDTA provocation test, the percentage of respondents recommending the use of any chelation therapy ranged from 16% for blood lead levels of 25 through 29 micrograms/dL to 66% for levels of 50 through 55 micrograms/dL.(ABSTRACT TRUNCATED AT 250 WORDS)


Hepatitis C infection in a pediatric dialysis population. A variable prevalence of hepatitis C (HCV) infection has been reported in adult patients on hemodialysis. We have studied HCV infection and associated risk factors in a pediatric dialysis unit. Sera from all 27 patients undergoing either hemodialysis or peritoneal dialysis in our unit were tested for antibody to HCV by enzyme-linked immunosorbent assay, and seropositives were confirmed by recombinant immunoblot assay. Records were reviewed for demographic, biochemical, and risk factor data. From the total of 27 patients (12 male, mean age 20.9 years, range 7.3 to 28.1 years), five were anti-HCV(+) (18.5%). All the anti-HCV(+) patients had been on hemodialysis (69 to 194 months, mean 105 months), while of the 22 anti-HCV(-) patients, only 14 had been on hemodialysis (5 to 209 months, mean 41.4 months), P less than .005. All the anti-HCV(+) patients had received blood transfusions (10 to 124 units, mean 61.4 units) as had 12 of the anti-HCV(-) patients (1 to 54 units, mean 14 units), P less than .02. Of the 5 anti-HCV(+) patients, only one had prior hepatitis B infection; of the 22 anti-HCV(-) patients, three had hepatitis B surface antigen, and no others had evidence of hepatitis B infection. The most predictive risk factor for HCV infection was length of time on hemodialysis. Eleven of the 27 patients (40.7%) had abnormal alanine aminotransferase values, of whom four were anti-HCV(+), three were hepatitis B surface antigen(+), and one was seropositive for antibody to human immunodeficiency virus.(ABSTRACT TRUNCATED AT 250 WORDS)


[Diagnosis of bacterial infections on vascular prosthesis. Histological and microbiological analysis]. A retrospective study of 212 vascular graft failures, using different criteria of infection evidenced a relatively high incidence of infectious complications. Vascular graft infection was assessed on one of the following criteria: clinical infection, positive bacteriological and/or virological examination of the graft, presence of characterized micro-organisms and of microstructures 0.1 to 0.5 micron in size at the blood/prosthesis surface at scanning electron microscopy, and presence of foci of persistent polymorphonuclear cells and lymphocytes at histological microscopy. In the absence of overlapping between these criteria, the present results raise the question of the adequacy of conventional bacteriological sampling on explanted artificial surfaces.


[Viral diarrheas].

[Viral diarrheas]. It is now well known that several viruses are responsible for acute diarrhoea or gastroenteritis in both children and adults. These viruses are difficult to identify since most of them cannot be isolated by stool cultures on cells. The reality of proven reinfection by some of these organisms is not always clearly understood, even though the existence of several serotypes in the same group (notably rotavirus) can be blamed, and this explains why vaccines are difficult to develop.