Mortality among workers employed in the pharmaceutical industry: a preliminary investigation. The cause-specific mortality experience of 826 plant employees and 249 sales representatives employed by a large U.S. pharmaceutical firm was examined to determine if there were unusual patterns of fatal disease that might relate to factors in the work environment. Deaths that occurred between 1954 and 1976 among actively employed or retired workers were identified through company records and a proportionate mortality analysis was carried out using the total U.S. as a standard. PMRs were computed for male and for female workers and for several broad occupational categories. A significant difference between observed and expected mortality from suicide was present in both males and females and there was an indication that drug overdoses were over-represented. PMRs for several cancer sites were elevated, but excesses were not always confined to particular occupational categories. Excesses of respiratory cancer were present in male maintenance workers and in female production workers. Increased relative frequencies of melanoma among males and of leukemia among females were confined to the production worker category. Some of the findings may provide leads for further investigations of the pharmaceutical industry.


Fluoride concentrations in urine of delivery ward personnel following exposure to low concentrations of methoxyflurane. Midwives and other delivery ward personnel exposed to methoxyflurane do not have measurable traces of the agent in expired air when examined soon after exposure. This may imply a rapid uptake of the anesthetic. If this is the case, then the products of the metabolism of methoxyflurane, such as fluoride, may appear in the urine of such personnel. The present study investigated urinary fluoride levels in 24 delivery ward personnel and compared the values found after methoxyflurane/nitrous oxide analgesia with those measured in the same individuals after exposure to nitrous oxide alone. A highly significant difference was observed. Thus it would appear that, in spite of an apparently adequate system of environmental ventilation, there is a significant uptake of methoxyflurane by delivery ward personnel when this agent is employed for obstetrical analgesia.


Is a healthier person less susceptible to noise-induced hearing loss? Several studies in the literature suggest that poor health is related to hearing loss. One hundred subjects claiming occupational hearing loss were chosen randomly for this study. Information was obtained on employment, noise exposure, medical history, family history, and use of cigarettes, alcohol, and medication. Physical examination audiometric tests, and biological tests were carried out. Computer analysis of the data with chi-square test did not show conclusively that noise-induced hearing loss is related to poor health, indicated by abnormal biological or physical findings, or both. There were, however, some indications that the presence of cardiovascular risk factors may influence hearing loss.


Spatial frequency masking in human vision: binocular interactions. Binocular contrast interactions in human vision were studied psychophysically. Thresholds were obtained for sinewave grating stimulation of the right eye in the presence of simultaneous masking gratings presented to the right eye (monocular masking) or left eye (dichoptic masking). In the first experiment, thresholds were measured at 0.25, 1.0, 4.0, and 16.0 cycle per degree (cpd) as a function of the contrast of masking gratings of identical frequency and phase. Thresholds rose nonmonotonically with masking contrast. At medium and high contrast levels, dichoptic masking was more effective in elevating contrast thresholds than monocular masking, and approached Weber's Law behavior. In the second experiment, spatial frequency tuning functions were obtained for test gratings at five spatial frequencies, by measuring threshold elevation as a function of the spatial frequency of constant-contrast masking gratings. At 1.0, 4.0, and 16.0 cpd, the tuning functions peaked at the test frequencies. The dichoptic tuning functions had a bandwidth of about 1 octave between half-maximum points, narrower than +/- 1 octave bandwidths of the monocular tuning functions. At 0.125 and 0.25 cpd, the tuning functions were broader and exhibited a shift in peak masking to frequencies above the test frequencies.


Bandpass channels, zero-crossings, and early visual information processing. Under appropriate conditions zero-crossings of a bandpass signal are very rich in information. The authors examine here the relevance of this result to the early stages of visual information processing, where zero-crossings in the output of independent spatial-frequency-tuned channels may contain sufficient information for much of the subsequent processing.


Spatial summation in human vision: simple reaction time measurements. The reaction-time technique was applied to examine spatial summation or area-intensity reciprocity at suprathreshold levels in the fovea. A family of reaction time vs luminance curves was measured in two experiments, and the luminance required to produce a criterion reaction time was computed from these curves to estimate the extent of summation. The first experiment showed that the upper level of spatial summation, the Ricco area, defined for constant reaction time increases with decreasing luminance level and that the upper limit of temporal summation is independent of the change in target size. The second indicated that the Ricco area decreases with increasing pulse duration up to 20-30 ms and then remains constant.


Using color substitution pupil response to expose chromatic mechanisms. It is well known that pupillary threshold shows a scotopic spectral behavior, even for foveal stimuli. However, when two scotopically balanced fields at different wavelengths are alternated, the pupil shows a constriction response at each transition, exposing innervation from chromatic mechanisms. Using a suitable model for pupillary innervation, this substitution response is systematically studied for different wavelengths and radiant power levels to yield (within the accuracy of the assumptions of the model) spectral threshold curves for the chromatic mechanism as indicated by the pupil. Four mechanisms have thus been identified, having peak sensitivities near 450, 525, 580, and 495 nm. We propose that these represent the blue, green, red and scotopic mechanisms as maintained before the level of the lateral geniculate body.


Chromaticity diagram showing cone excitation by stimuli of equal luminance. In a space where Cartesian coordinates represent the excitations of the three cone types involved in color vision, a plane of constant luminance provides a chromaticity diagram in which excitation of each cone type (at constant luminance) is represented by a linear scale (horizontal or vertical), and in which the center-of-gravity rule applies with weights proportional to luminance.


Microscopic hematuria in school children: epidemiology and clinicopathologic evaluation. An unselected population of 8,954 children, age 8 to 15 years, was screened for hematuria. Four urine specimens from each were examined; microscopic hematuria was found in one or more specimens in 4.1%, and in two or more specimens in 1.1% of the children. The prevalence was not age or sex dependent. Those with two or more positive samples were re-examined twice during a half-year period: 33 had hematuria of 6 or more RBC/0.9 mm3, or more than 100,000 RBC/hour, on both occasions; renal biopsy performed on 28 of them revealed two cases of IgA-IgG nephropathy, one of focal segmental sclerosis, one of extracapillary glomerulonephritis, and one of possible hereditary nephritis. In 12 patients the biopsy was entirely normal; the rest showed equivocal changes. Co-existing proteinuria and the degree of hematuria correlated well with the severity of the morphologic alterations. Pathologic findings in microscopic hematuria seem to be less frequent than in hematuria in general; in most such patients, renal biopsy is probably not indicated. In some children the low-grade hematuria may merely represent the upper end of physiologic variation.


Morbidity in breast-fed and artificially fed infants. II. The advantages of breast-feeding in reducing morbidity was previously shown in a group of rural infants. Those observations are extended and refined. The protection afforded by breast-feeding is greatest during the early months, increases with the duration of breast-feeding, and appears to be more striking for serious illness. It operates independently of the effect of associated factors such as socioeducational status, family size, day-care exposure, and birth weight.


Autosomal dominant microcephaly.

Autosomal dominant microcephaly. Four families with autosomal dominant microcephaly are reported. Although the phenotype is nondistinctive, several patients had receding or small foreheads, upslanted palpebral fissures, or prominent ears. The degree of intellectual dysfunction is not as severe as that recorded in autosomal recessive microcephaly. It would appear that autosomal dominant microcephaly is more common than previously recorded, and that head circumference measurements of siblings and parents of affected patients should become a part of the initial investigation.


Neuropsychologic consequences of Reye syndrome. Behavioral measurement of brain function was conducted in 40 children, one or more years after their recovery of Reye syndrome. Test measures included standard indices of intelligence, school achievement, visual-motor coordination and social maturity, plus the Halstead-Reitan Neuropsychological Batteries. There was a strong correlation between the degree of impaired neuropsychologic function and clinical grade at admission, the duration of impaired consciousness, and the number of exchange transfusions required. Patients with milder disease had normal brain function and fewer school problems. Language and perceptual-motor performance significantly improved with increasing years in recovery, suggesting that some of the disturbances of brain functioning are transient. The statistical analysis indicated that there are lasting, often subtle disturbances of higher cognitive function as a result of Reye syndrome. These deficits, not always apparent on clinical examination, are clearly correlated with the extent of neurologic involvement. This quantitative assessment of neuropsychologic function is a basis for determining the "quality of survival" in Reye syndrome, and such measurements should be included in the comparative evaluation of Reye syndrome treatment programs.


The nutritional therapy of histidinemia. Control of the plasma histidine level in histidinemia is possible with the use of an amino acid mixture free of histidine and a carefully monitored intake of histidine. This regimen is compatible with good physical growth and normal mental development. If further clinical experience demonstrates that widespread nutritional intervention in this disease is warranted, it should be possible to obtain good biochemical control.


The pulse wave arrival time (QKd interval) in normal children. The interval between the onset of QRS of the electrocardiogram and the arrival of the pulse wave at the brachial artery, as detected by the appearance of Korotkoff sounds at diastolic pressure (QKd), provides a measure of a pulse wave arrival time, i.e., the sum of the pre-ejection period and a pulse transmission time. This measurement has proven useful in the evaluation of cardiovascular disease, thyroid and catecholamine status, and several other conditions in adults. In order to standardize this measurement in children, measurements were obtained on 63 normal children ranging in age from 7 months to 18 years. Because of the dependence of pulse transmission time on the distance of propagation, the QKd interval (in msec) is related to height (H in cm) by the equation: QKd = 56.6 + 0.797H. By use of this equation one can obtain a "height corrected QKd." Correction for pulse rate is not necessary for resting subjects. These normal ranges permit use of the QKd interval for clinical studies in children. These studies also permit measurement of the mean pulse wave velocity for a group of individuals. PWV (m/sec) increases with age according to the equation: PWV = 2.44 + 0.203 A, (A in years) with a correlation coefficient of r = 0.823. This implies progressive loss of functional elasticity of the major arteries throughout childhood.


Who pays the bill for neonatal intensive care? The Children's Hospital Newborn Emergency Service conducted 174 transports to the Newborn Center during a four-month period in 1976. The transport charge directly related to the distance between the referring hospital and the NBC. Two years after the NBC discharged the last study infant, 150 of 174 accounts have been paid in full. Insurance paid 85%, families paid 4%, and the hospital wrote off 11% of all hospital charges. The Children's Hospital referred 2% of all hospital charges to a bill collection agency. One hundred-forty-four infants (84%) survived and 27 (16%) died. The mean charge per day for survivors was $338; the mean charge per day for nonsurvivors was $607.


A simplified score for assessment of fetal maturation of newly born infants. A simplified scoring system for clinically determining fetal maturation of newly born infants has been developed and provides accurate assessment of gestational age in either well or sick babies. Certain conditions render individual criteria within the score less reliable but do not significantly lessen the reliability of the total assessment. The optimal age for maturational assessment is between 30 and 42 hours of age.


Noninvasive diagnosis of neonatal asphyxia and intraventricular hemorrhage by Doppler ultrasound. The cerebrovascular hemodynamic alterations in asphyxia and intracerebral-intraventricular hemorrhage were determined by monitoring the pulsatile flow changes in the anterior cerebral arteries using Doppler ultrasound. The pulsatility index measurements, which were calculated from the recorded changes in Doppler frequency shifts, were obtained in four groups of newborn infants with the following diagnoses: Group I--normal term (n=21); Group II--asphyxia (n=12); Group III--IC-IVH (n=14); and Group IV--asymptomatic preterm (n=11). There was no significant difference between PI values of Groups I and IV. Compared to normal term infants, those diagnosed as having asphyxia had significantly lower PI measurements and those with IC-IVH had significantly higher PI values than the asymptomatic pretern infants. Serial Doppler studies were also performed in 22 preterm infants with respiratory distress. One-half of these infants subsequently developed IC-IVH. Prior to hemorrhage, their PI measurements were significantly lower than those who did not eventually have the complication. The low PI values in asphyxia and prior to the onset of IC-IVH indicate vasodilation and decreased resistance to blood flow. In IC-IVH, the high PI measurements denote the opposite. In infants with respiratory distress in the presence of significant vasodilation and lowered vascular resistance, CBF may increase to excessive levels, resulting in IC-IVH.


Postnatal development of renal sodium handling in premature infants. To estimate the contribution of the specific defect in proximal and distal tubular reabsorption of sodium to renal salt wasting, fractional sodium excretion, distal tubular sodium delivery, and distal tubular sodium reabsorption were determined in 11 healthy premature infants. The study was performed on the seventh day and at weekly intervals thereafter up to the sixth week of life. Sodium clearance and fractional sodium excretion decreased significantly with increasing postnatal age (P less than 0.001). There was no significant alteration in either osmolar or free-water clearances. Distal tubular sodium delivery steadily decreased from 4.96 +/- 0.66 (mean +/- SE) in the first week to 3.3 +/- 0.41 ml/minute/dl GFR in the sixth week of life (P less than 0.05). Distal tubular sodium reabsorption was 69.5 +/- 2.36% in the first week, then rose significantly to reach a value of 83.7 +/- 1.85% in the second week (P less than 0.001) and remained practically unchanged thereafter. It is suggested that the rapid improvement of distal tubular sodium reabsorption in premature infants might result from forced stimulation by the excessively activated renin-angiotensin-aldosterone system.


Multicystic encephalomalacia in liveborn twin with a stillborn macerated co-twin. Computed tomography showed multiple cystic lesions in the brains of three infants with cerebral palsy. Each patient was the product of a twin pregnancy with a stillborn, macerated co-twin. In two patients angiography was performed and suggested that the cystic lesions were multicystic encephalomalacia due to perinatal arterial occlusion.


Bronchopulmonary dysplasia--pathology.

Bronchopulmonary dysplasia--pathology. The term bronchopulmonary dysplasia has much to commend it. It does not declare the etiology of this disease, which seems to be an advantage. Another advantage is that it presents the idea of disturbance of growth as well as scarring. The premature lung responds at birth somewhat differently from the mature lung, not just in respect to surfactant but from the point of view of the blood vessels' size and compliance. But treatment must also be considered. The administration of steroids to the mother in the antenatal period probably favors maturation in the fetus, rather than growth of size and cell multiplication, which will also influence the behavior of the lung postnatally. This is probably a critical feature to look for in clinical assessment and follow-up of these patients.


Neuroblastoma presenting with the nephrotic syndrome. A case of neuroblastoma in a 4-yr-old boy presenting with the nephrotic syndrome is reported. Nether thrombosis nor stenosis of the renal veins and the inferior vena cava was present. Electron microscopy revealed lumps of subepithelial deposits as well as thickening and tortuosity of the glomerular basement membrane compatible with membranous nephropathy. It is postulated that deposition of neuroblastoma-associated immune complexes on the glomerular basement membrane-was responsible for the development of the nephrotic syndrome in this patient. Five pediatric cases of nephrotic syndrome associated with extrarenal neoplasia were collected from the world literature and are briefly discussed.


Neuroblastoma masquerading as congenital ureteropelvic junction obstruction. A case of perirenal neuroblastoma causing intrarenal obstruction of the pelvis of the kidney presented as a small hydronephrosis at 3 days of age. The tumor grew rapidly over the next 48 hr, diagnosis was confirmed by ultrasonography, and the mass was removed surgically.


Histoplasmosis simulating lymphoma in children. The experience of two Mineapolis hospitals with histoplasmosis over a 10-yr period was reviewed. Six of eleven pediatric patients with histoplasmosis presented with systemic symptoms, a mediastinal mass, and no pulmonary infiltrates. A clinical diagnosis of lymphoma was made in each case. Immediate radiation therapy for respiratory compromise was considered in one patient before pathologic diagnosis revealed primary histoplasmosis of the mediastinum. Although immediate therapy with steroids or irradiation is often considered in patients who have acute respiratory embarrassment caused by a mass, histologic confirmation of the diagnosis is always indicated before such therapy is instituted. Primary histoplasmosis of the mediastinum may be more common than previously thought.


The value of emergency open lung biopsy in infants and children. The records of 36 infants and children who underwent emergency open lung biopsy at the Hospital for Sick Children, Toronto, between 1969 and 1976 were studied in order to assess the safety and value of performing this procedure in patients with failing respiratory function. Prior to their respiratory illness, 14 of these patients were receiving steroids, chemotherapy, and radiotherapy singly or in combination as treatment for various sytemic diseases of which leukemia was the most prominent. In all cases the biopsy was performed under general anesthesia and lasted about 1 hour. The biopsy was diagnostic in all but one of these children, permitting the institution of appropriate therapy. Six preventible postoperative complications required treatment but there were no deaths attributable to operation in this series. Emergency open lung biopsy is strongly recommended even in patients in severe respiratory failure when all routine investigations fail to yield a diagnosis.


Multiple pulmonary fibroleiomyomatous hamartomata in childhood. A 9-yr-old girl with a history of rhabdomyosarcoma developed multiple pulmonary fibroleiomyomatous hamartomata. This clinical setting illustrates the tendency of these hamartomata to clinically mimic metastatic tumors. Further, this case represents the first description of multiple pulmonary fibroleiomyomatous hamartomata in a pediatric age group, and finally, in this clinical setting, supports the concept that these hamartomata represent a distinct entity apart from benign metastasizing uterine leiomyomata.


The twin with esophageal atresia.

The twin with esophageal atresia. A retrospective analysis of esophageal atresia occurring in patients who are members of a twin set indicated that twinning does occur more frequently in patients with esophageal atresia. These patients tend to be small for date, but have a similar occurrence of associated anomalies as singletons with esophageal atresia. Applying risk-grouping to the entire series and twins indicated no real difference in survival or additional anomalies by organ system, except more cardiovascular anomalies occurred in twins. Long-term follow-up of five survivors revealed severe growth retardation.


Plain film detection of right aortic arch in infants with esophageal atresia and tracheoesophageal fistula. The aortic arch can be clearly demonstrated in neonatal chest radiographs by use of a high kilovoltage-filtered film with air-gap magnification. This allows identification of the presence of right aortic arch in patients with esophageal atresia and tracheoesophageal fistula; awareness of this anomaly may influence choice of surgical approach.


Effect of proximal gastric vagotomy and truncal vagotomy and pyloroplasty on gastric functions and growth in puppies after massive small bowel resection. The effects of truncal vagotomy and pyloroplasty and proximal gastric vagotomy on gastric acid hypersecretion, hypergastrinemia, and growth after massive bowel resection were studied in beagle puppies. In puppies with 80% enterectomy, neither type of vagotomy alters significantly the postprandial hypersecretion of acid from the Heidenhain pouch or the concentration of serum gastrin. Proximal gastric vagotomy tended to decrease the hypersecretion more than did truncal vagotomy. In beagle puppies undergoing 70% small bowel resection, growth was significantly decreased but survival was not impaired. Neither proximal gastric vagotomy nor truncal vagotomy and pyloroplasty reversed completely the impaired growth produced by massive resection. Proximal gastric vagotomy caused a small improvements in growth, while truncal vagotomy and pyloroplasty resulted in a slight decrease in growth. It remains possible that proximal gastric vagotomy could be of value in the management of growing infants with hypersecretion of acid due to short bowel syndrome.


Pyloric atresia and epidermolysis bullosa letalis: a lethal combination in two premature newborn siblings. Pyloric atresia and epidermolysis bullosa letalis are rare congenital anomalies. The association of the two diseases in siblings has not been reported previously. This paper describes such as association in two newborn infants of caucasian parents with no family history of similar anomalies. Problems in management included severe fluid and electrolyte losses, systemic infection, and prematurity, which led to the death of the two infants. The question is raised whether the two abnormalities are expressions of closely linked genes. The presence of epidermolysis bullosa should alert the pediatrician to the possiblity of a coexisting pyloric atresia.


Preoperative diagnosis of splenic cysts in children by gray scale ultrasonography. Ultrasonography is a useful noninvasive modality for the diagnosis of splenic cysts in children. Characteristic features plus the typical clinical and radiographic presentation should obviate the need for further more invasive and costly techniques which add little to diagnostic accuracy. Additional advantages offered by ultrasound a minimal patient discomfort, no ionizing radiation, and immediate reassurance to parents that the mass is a cyst. We report two cases of epidermoid splenic cysts preoperatively diagnosed by ultrasonography. The typical sonographic characteristics are presented and the sonographic differential diagnosis is discussed.


Colon sarcoma in the newborn.

Colon sarcoma in the newborn. Two newborns with similar lesions were treated at two children's hospitals. Each newborn presented with an abdominal emergency that required immediate surgery. In each instance, small bowel obstruction was clinically and radiologically suspected; barium enema examination showed an irreducible colonic intussusception in the first baby and a colonic perforation in the second. Both these findings required immediate operation. The baby with the intussusception had a colon resection and a primary anastomosis, while the newborn with the perforation had a resection and temporary colostomy. Subsequent to the initial surgery, neither baby has received any further treatment for the tumor. The two patients are now well at 13 yr and 6 yr of age.


Malabsorption and pouch ulcerations following the Martin repair for total colonic aganglionosis. A late complication of the Martin repair for total colonic aganglionosis is described. Pouch malfunction resulted in stasis and ulceration, excessive blood and protein loss, and bacterial overgrowth of the small intestine. The severity and nature of the lesion was identified by colonoscopy.


Malignant melanoma in children.

Malignant melanoma in children. Six patients with prepubertal malignant melanoma are presented. Three were metastatic. One was congenital in a giant pigmented nevus. A second was found at 6 mo of age to have metastatic lesions. All were treated aggressively and had a favorable outcome. Aggressive treatment, once malignant melanoma is diagnosed, is recommended. Prognosis does not differ markedly from similar lesions in adults.


Hemithyroid agenesis associated with a cervical thymic cyst. A case is presented of a 7-yr-old boy with left hemithyroid agenesis associated with cervical thymic cyst. No left parathyroid glands were found. The diagnosis was established after surgical excision and histologic examination. Clinical and embryological implications of this condition are briefly discussed. No similar case has been found in the literature.


Traumatic intercostal hernia due to a nonpenetrating injury in a child. Herniation of the lung is a recognized, though rare, complication of thoracotomy and penetrating chest injury. Closed chest injury is usually associated with rib fractures, laceration of the lung, and rupture of the diaphragm, bronchus, and aorta. It is unusual for the intercostal muscles to be ruptured in a closed chest injury. In this case, herniation of the lung may result.


Eventration of the diaphragm due to phrenic nerve injury caused by intercostal drainage. Acquired eventration of the diaphragm is caused by injury to the phrenic nerve with resultant paralysis and elevation of the entire diaphragm. In this reported case, damage to the phrenic nerve was caused by an intercostal drain. This has not been previously reported.


Congenital lumbar "pseudohernia".

Congenital lumbar "pseudohernia". At the age of 11 mo, a boy, born by breech presentation, was seen with signs suggesting a congenital lumbar hernia. Signs of already healing epiphysiolysis humeri and costal fractures suggested a traumatic origin of the hernia due to neuropraxia of the intercostal nerves. Full recovery ensued without active treatment.


Leiomyoma of small bowel: a case report. Benign small bowel tumors are rare and usually present in late adult life. Because of its raity, a case of benign leiomyoma of the small bowel presenting with distal small bowel obstruction in childhood is reported, with a discussion of the principles of management.


Volvulus of the sigmoid colon.

Volvulus of the sigmoid colon. Sigmoid volvulus in children is quite rare and may occur in acute fulminating form requiring early diagnosis and surgery. In this case, bowel continuity after resection of the necrotic sigmoid was reestablished in a two-stage operation.


Pseudomonas septicemia; necrotizing bowel lesions (NEC) and skin lesions in a 5-mo-old child. Necrotizing enterocolitis (NEC) that occurs in the high risk neonate is not usually associated with pathogenic organism. In older children the presence of NEC is often due to infection with a specific pathogen. A case of a five month old child with pseudomonas aeruginosa septicemia presented with typical NEC. in the course of two laparotomies, most of the small bowel was resected. Necrotizing skin lesions were also present, and the likely source of both of these lesions were septic embolic.


Sex differences in feelings attributed to a woman in situations involving coercion and sexual advances. This study investigated sex differences of feelings attributed to a woman in situations involving varying degrees of coercion and sexual advances. Sixteen vignettes (12 dealing with sex and coercion, 4 dealing with coercion only) were rated on 17 semantic differential scales by 59 undergraduates (44 females, 15 males) and 45 graduate students (18 females, 27 males). The 16 vignettes yielded factors of Sexual Flattery/Overtures, Sexual Aggressiveness, and Violence. Factor analyses of the 17 semantic differential scales yielded factors of Helplessness, Aversiveness, and Threat. High agreement was found between males and females in both the graduate and undergraduate samples on the relative intensity of feelings attributed to the woman across the sex/coercion vignettes for the three dimensions of Helplessness, Aversiveness, and Threat. Even more importantly, systematic differences between males and females on intensity of attributed feelings across the semantic differential factors were independently replicated using the graduate and undergraduate samples. Analyses of variance revealed that males showed significantly greater attributions on the factors Helplessness and Threat on scenes mainly dealing with sexual flattery/overtures, whereas they showed significantly less attributions on the factor Aversiveness on scenes dealing with sexual aggressiveness and rape. In short, while there was strong agreement between men and women, there were also replicated significant systematic differences with men overestimating the psychological impact of less intense incidents and underestimating the psychological impact on women of more intense incidents.


The structure of nonverbal decoding skills. The structure of skill at decoding nonverbal cues was examined for 150 high school students and 95 college students. An overall principal components analysis yielded four factors differing in the complexity of the message (pure versus mixed) and in the relative importance of the video versus the audio modality. Factor 1 (pure video) was defined by accuracy at face and body cues of ordinary (2 second) and very brief exposure length. Factor 2 (mixed video) was defined by accuracy at face and body cues with a "noisy" background. Factor 3 (mixed audio) was defined by accuracy at decoding discrepant cues and "noisy" audio cues. Factor 4 (ure audio) was defined by accuracy at pure tone of voice cues. The overall evidence suggested that despite a nontrivial degree of relationship among all measures of skill at decoding nonverbal cues (Armor's Theta = .62), it would increase our theoretical and empirical precision to conceptualize nonverbal decoding ability as made up of several relatively unrelated subskills.


Effects of personality and loss of anonymity on aggression: a reevaluation of deindividuation. Zimbardo's deindividuation hypothesis was reexamined by individuating some subjects. Twelve four-person groups administered shock to a confederate in a 2 x 2 x 2 factorial design with two levels of social individuation (subjects' level of anonymity to group members), two levels of nonsocial individuation (subjects' opportunity to give identifying information to the experimenter on a word association test) and two levels of individual differences. It was found that subjects, who individuated themselves by giving information to the experimenter on the word association test showed more, not less, antisocial behavior. Furthermore, this increased antisocial behavior was exhibited only by externally oriented subjects: those with an external locus of control and a low mysticism score. Some of those more antisocial subjects were also more likely to report feeling like they stood out from the group. It was concluded that antisocial behavior in this paradigm may thus be a response to experimenter demand felt most strongly when subjects felt most identifiable.


Cardiovascular changes during social competition in a mixed-motive game. Male and female subjects played a mixed-motive game against a male confederate under either a 20% cooperative or an 80% cooperative strategy while cardiovascular responses were computer monitored. Females had larger heart rate responses than males during play against the competitive strategy, and the opposite was true during play against the cooperative strategy. Subjects who were more competitive during the game or who scored higher on a coronary-prone (Type A) behavior scale or who reported having an action orientation toward life stress tended to have larger heart rate responses during the game than the remaining subjects. The results draw attention to the importance of covert autonomic responses for understanding overt behavioral choices in mixed-motive games and to the potential utility of this behavioral model for studying the role of psychosocial factors in psychosomatic illnesses.


Vocal interruptions in dyadic communication as a function of speech and social anxiety. Interruptions have been defined as a breach of the "turn-taking" contract in interpersonal communication. The relation between a speaker's personality and his or her propensity to interrupt was examined in 30-min unstructured conversations for 36 dyads (12 male, 12 female, and 12 mixed sex). The following predictions were made: (a) Interruptive behavior is inversely related to speech anxiety and positively related to confidence as a speaker; (b) interruptive behavior is inversely related to social anxiety (avoidance-distress; fear of negative evaluation). A stepwise multiple regression analysis was performed, controlling for the systematic effects of sex, the conversational partner's personality and amount of speech, and the speaker's use of back-channel responses. These hypotheses were confirmed for rate of total interruptions and rate of successful interruptions, for percentage of successful interruptions, and for mean duration of interruptions; the results withstood cross-validation analysis.


Effects of difficulty and diagnosticity on choice among tasks in relation to achievement motivation and perceived ability. The experiment is a partial replication of a study conducted by Trope. It investigates the effects of two person characteristics (achievement motive and perceived own ability) and two task characteristics (difficulty and diagnostic value about own ability) on choice among achievement tasks. In accordance with the results of Trope, it was found that high-diagnostic tasks were preferred to low-diagnostic tasks, independent of their difficulty. Trope's finding that high resultant achievers choose high-diagnostic tasks over low-diagnostic tasks to a greater extent than low resultant achievers was not replicated. However, the perceived degree of own ability affected choice behavior: When easy and difficult tasks were both high in diagnosticity, subjects high in perceived ability preferred difficult over easy tasks, whereas subjects low in perceived ability preferred easy over difficult tasks. From this latter finding it is concluded that a self-informational conception of choice behavior has to include the subjective probability of success at tasks as a determinant of choice, in addition to objective difficulty and diagnostic value.


Focus of attention, chronic expectancy, and responses to a feared stimulus. An attentional model of fear-based behavior is proposed and a study that tested the model is reported. It was predicted that among subjects with moderate fear of snakes, heightened self-attention during an approach attempt would cause increased awareness of existing anxiety, followed by one of two courses of events: Subjects who believed that they could do the behavior in spite of their fear were expected to redirect their attention to the behavior--goal comparison and exhibit no behavioral deficit. Subjects who doubted their ability to do the behavior were expected to divert their attention from the behavior--goal comparison and to withdraw behaviorally from the approach attempt. The results of the study support this reasoning. Discussion centers on relationships between the proposed model and previous theory.


Expressive tendencies and physiological response to stress. This study assessed the effects of natural expressive tendencies on physiological response to stress. Male undergraduates were unobtrusively observed while watching a stressor videotape. On the basis of the subjects' facial responsiveness to the film, a group of 23 natural expressers and 22 natural inhibitors were selected and exposed to a threat of shock situation during which heart rate, respiration rate, skin conductance, and facial expressions were monitored. In accord with the discharge model of emotion, natural inhibitors were less facially expressive and more physiologically reactive to the shock threat than were natural expressers. The results also demonstrated that overt expressivity is stable over time and situation. On personality measures, natural expressers scored significantly higher on Mehrabian's empathic tendency scale, thus supporting the efficacy of this paper-and-pencil instrument as a measure of non-verbal responsiveness. The two groups did not differ on measures of self-esteem, introversion--extraversion, or locus of control. The results are discussed in terms of the discharge model as a descriptive metaphor and not a causal theory.


Possible involvement of prostaglandins in the action of ATP on guinea-pig uterus. ATP and other adenine derivatives, such as AMP and adenosine, at concentrations above 10(-6) M induced dose-dependent contractions of guinea-pig uterine strips. Treatment of the strips with nonsteroidal anti-inflammatory drugs, such as indomethacin, aspirin and phenylbutazone, at concentrations of 10(-6) to 10(-4) M irreversibly inhibited the contractions, without affecting those caused by acetylcholine and bradykinin. Arachidonic acid (10(-8)-10(-6) g/ml) and prostaglandins (E1, E2 and F2 alpha, 10(-9)-10(-7) g/ml) restored the inhibited uterine response to ATP, but the inhibition was reinstated on washing out of the arachidonic acid or prostaglandins. Furthermore, the prostaglandin antagonists polyphloretin phosphate (3 x 10(-5)-3 x 10(-4) g/ml) and SC 19220 (10(-6)-3 X 10(-5) M) selectively suppressed the action of ATP. In addition to the prostaglandin antagonists, 2,2'-pyridylisatogen, reported to be an ATP antagonist, at concentrations of 10(-6) to 3 x 10(-5) M selectively inhibited the response of uterine strips to ATP. These results suggest the involvement of prostaglandins in the actions of ATP and other adenine derivatives on guinea-pig uterine tissue and provide further evidence for ATP-stimulated prostaglandin formation in smooth muscle.


Stimulation of p-nitroanisole O-demethylation by ethanol in perfused livers from fasted rats. Low concentrations of ethanol (0.2 mM) stimulated p-nitroanisole O-demethylation in perfused livers from fasted, but not fed, phenobarbital-treated rats. The increase in mixed-function oxidation correlated well with the production of NADH from ethanol metabolism (Ka for both processes = 0.2-0.3 mM). This stimulation by ethanol was blocked by 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, and pyruvate, a substrate for lactate dehydrogenase. Under these conditions, the characteristic reduction of NAD+ by ethanol was also abolished. p-Nitroanisole O-demethylation by isolated hepatic microsomes was unaffected by low concentrations of ethanol (up to 2 mM); however, when NADH was added to the microsomes, or was generated from ethanol, alcohol dehydrogenase and NAD+, a synergistic increase in p-nitroanisole metabolism occurred. Sorbitol and xylitol, two carbohydrates which reduced pyridine nucleotides in perfused livers, also stimulated p-nitroanisole O-demethylation in livers from fasted rats. The data indicate that NADH produced from the metabolism of ethanol, sorbitol and xylitol stimulates mixed-function oxidation in livers from fasted animals.


Antiplatelet drugs and the generalized Shwartzman reaction in the pregnant rat. Several antiplatelet drugs (aspirin, sulfinpyrazone, hydroxychloroquine, dipyridamole, BL-3459, pyridinolcarbamate) were assayed for their ability to prevent the generalized Shwartzman reaction initiated by endotoxin in the pregnant rat, and compared to glucocorticoids (dexamethasone, hydrocortisone). The drugs were administered in a single large dose a few hours before provocation of the reaction. In opposition to glucocorticoids and beside BL-3459 which interfere with other mechanisms involved in the phenomenon, the tested inhibitors of platelet aggregation were found incapable of preventing or reducing the severity of the Shwartzman reaction.


Studies on the N-demethylation and O-de-ethylation of ethylmorphine[6-3H] by male rat hepatic microsomes. A sensitive and convenient radioassay for the in vitro determination of ethylmorphine N-demethylase and O-de-ethylase activity has been developed. Ethylmorphine[6-3H] was prepared by reduction of the corresponding morphinone in nearly quantitative yield. After incubation with hepatic microsomes from male rats, the reaction was terminated by the addition of 5 ml of acetone. The sample was saturated with potassium acetate and extracted twice with acetone giving complete extraction of the radiolabeled ethylmorphine and its metabolites. After the combined organic phases were evaporated, the samples were dissolved in methanol and applied to a Silica Gel GF plate with subsequent development in ethyl acetate-methanol-concentrated NH4OH. The amount of radioactivity detected for the morphine and norethylmorphine bands at zero time was approximately 0.05% of the original amount of labeled ethylmorphine added to the incubation media. Similarly, the Km values were 52 and 250 microns for the O- and N-dealkylation respectively, while the Vmax values were 5.0 and 1.8 nmol/mg of protein per min. Finally, with this assay we have observed constant specific activity for both the N- and O-dealkylation of ethylmorphine[6-3H] with as little as 10 micrograms of microsomal protein per ml of incubation media.


Release of endogenous norepinephrine from a rabbit cerebral artery. Cerebral arteries are relatively unresponsive to sympathetic nerve stimulation, in spite of extensive adrenergic innervation. To determine whether these nerves are functional, release of endogenous norepinephrine (NE) was measured using a radioenzymatic assay. Fractional release of NE per stimulation pulse was more than 5 times greater from the rabbit basilar artery than from the ear artery. Thus, while the NE content of the two vessels is quite similar, transmitter release is considerably greater in the basilar artery. Since NE accumulation is also much greater in the basilar artery, it seems possible that an active parameter such as NE release or accumulation may be a better index of functional nerve capacity than NE content. Previous studies have shown that alpha adrenergic blocking agents do not block the contractile response to nerve stimulation of the basilar artery, but actually increase it. Thus, the possibility that blockade of presynaptic adrenergic receptors leads to increased transmitter release was tested. Indeed, both phenoxybenzamine and phentolamine significantly increased stimulation-evoked NE release. It appears that postsynaptic events in cerebral arteries are atypical, while release of transmitter, including modulation by presynaptic alpha adrenergic receptors is similar to other blood vessels.


Renal effects of enflurane anesthesia in Fischer 344 rats with pre-existing renal insufficiency. Chronic renal insufficiency was produced surgically in Fischer 344 rats in order to evaluate the effects of enflurane anesthesia in animals with impaired renal function. Three groups of rats were anesthetized with enflurane: a control group without impairment of renal function (n = 7); a group with minimal impairment of renal function (n = 6); and a group with moderately severe renal impairment (n = 9). Another group of rats with moderately severe renal impairment (n = 8) was anesthetized with halothane. Two hours of anesthesia resulted only in mild transient depression of urea clearance in all groups. Six hours of anesthesia resulted in a 5 to 10 ml/day increase of urinary output in all groups and small increases in urea nitrogen levels in both groups with moderately severe renal impairment. Deterioration of the model was noted late in the experiment; at sacrifice, animals that had been anesthetized with enflurance and four with halothane had terminal renal failure. The morphological lesion in both groups was similar, resembling glomerulonephritis. Thus, there was no difference in the renal response to enflurane or halothane anesthesia among rats with chronic renal insufficiency.


Procaine as an acetylcholine agonist in snail neuron. Low concentrations of procaine (10(-5) M) are capable of provoking changes in the membrane potential of snail neurons. This effect is produced by direct application to the membrane and is characterized by a short response time and rapid reversibility. The resulting potential change has the same properties as that which follows acetylcholine application, including the same change of membrane resistance, the same relationship with membrane potential, the same ionic dependence and, finally, the same pharmacological sensitivity. The identity between the acetylcholine and procaine responses holds both for cells depolarized and cells hyperpolarized by acetylcholine. This procaine sensitivity involves only about two-thirds of the cells and it is concluded that procaine activates the cholinergic receptor on these cells.


Secretion and metabolism of cortisol and aldosterone during controlled hyperthermia. 1. The rates of secretion and metabolic clearance of cortisol and aldosterone in response to passive heating have been investigated in fifteen young men by the controlled hyperthermia technique combined with continuous I.V. infusion of [14C]cortisol and [3H]aldosterone. 2. During a 1 hr period of elevation of deep body temperature to 38.0 degrees C mean hepatic blood flow measured by indocyanine green clearance decreased by more than 25% compared with normothermic condition. 3. The pattern of response in hyperthermia involved decreasing plasma specific activities indicating increased adrenal secretion of both cortisol and aldosterone. 4. Aldosterone metabolic clearance rate usually decreased in hyperthermia when there was little change in the clearance rate of cortisol, but an increased aldosterone clearance rate was observed when there were significant increases in the clearance rate of cortisol. A contributing factor to elevation of plasma aldosterone concentration in the heat is the reduction in hepatic blood flow which reduces aldosterone metabolic clearance rate. 5. Suppression of the thermally induced rise in plasma cortisol concentration by dexamethasone was associated with a decrease in aldosterone clearance rate which may reflect increased availability of aldosterone-binding plasma protein. 6. Marked rises in plasma cortisol were always accompanied by simultaneous rises in aldosterone, but rises in aldosterone sometimes occurred in the absence of a rise in cortisol. We therefore suggest that ACTH stimulation plays an important, but not exclusive, role in the stimulation of aldosterone secretion during hyperthermia.


Numerical solution of coupled transport equations applied to corneal hydration dynamics. 1. A quantitative basis for the currently accepted theory on the regulation of corneal hydration was derived using the technique of finite element analysis to integrate a set of coupled flow equations. The model was based on non-equilibrium thermodynamics and incorporated the transport and permeability properties of the corneal epithelium and endothelium as well as the gel properties of the central connective tissue layer. 2. Considerable errors were introduced in the prediction of corneal hydration dynamics (unsteady-state behaviour) unless allowance was made for the development of trans-stromal gradients in pressure and solute concentration. 3. Thickness of in vitro rabbit corneal epithelium and stroma were measured with an automatic specular microscope during responses to changes in the osmolarity of the tear-side bathing medium. The time course of these experiments was fitted with the mathematical model to obtain a set of membrane phenomenological coefficients and transport rates. 4. The model with the redetermined membrane parameters was tested by predicting the influence of other variations in boundary conditions with excellent match to several well-documented experimental observations, including an explanation for the slight stromal swelling observed in hibernating mammals. 5. The regulation of corneal stromal hydration can be explained accurately by balance between the dissipative flows across the serial array of corneal layers and the active HCO3 transport by the endothelium, supporting the earlier 'pump-leak' hypothesis. 6. It was found that stromal retardation of fluid flow, as well as gradients in solute concentration, significantly influences the dynamics of corneal stroma hydration. Tissue gel properties may be a more important factor in coupled transport across cell layers than generally appreciated.


Afferent sympathetic unmyelinated fibres with left ventricular endings in cats. 1. We recorded the electrical impulse activity of thirty-three single afferent fibres with left ventricular endings from the third and fourth left thoracic sympathetic rami communicantes of anaesthetized cats. Their conduction velocity ranged from 0.23 to 0.98 m/sec (group C). 2. The endings of each fibre were localized to the left ventricle by mechanical probing performed at the end of the experiment on the non-beating heart. No fibre had multiple sensory fields. 3. The impulse activity (0.95 +/- 0.2 impulses/sec) was spontaneous but most often a fixed temporal correlation between impulses and ventricular dynamics was not detectable. It was increased during occlusion of the thoracic aorta, I.V. administration of isoprenaline or infusion of saline. It was unaffected by asphyxia, haemorrhage and I.V. administration of acetylcholine. It was decreased during occlusion of inferior vena cava. Therefore these ventricular receptors appeared to be mainly sensitive to mechanical events. 4. The fibres were excited during the occlusion of the left main coronary artery, after a latency of 14.5 +/- 1.3 sec. They were also excited during ventricular fibrillation, exhibiting the highest values of impulse activity (2.51 +/- 0.4 impulses/sec). The increase in impulse activity during ventricular fibrillation was sometimes immediate and extreme, with peak frequencies of about 50 impulses/sec. 5. These spontaneously active ventricular receptors with unmyelinated nerve fibres participate in the transmission of the continuous impulse activity which from the cardiovascular system reaches the spinal cord through the sympathetic nerves and which is likely to contribute to the neural control of circulation. Thus the unmyelinated cardiac sympathetic afferents should not be considered as purely nociceptive in function.


Propagation of electrical spiking activity along the small intestine: intrinsic versus extrinsic neural influences. 1. The electrical activity of the small intestine of conscious dog, recorded by means of chronically implanted electrodes, was related to the transit time estimated by phenol red infusion and its propagation observed after a single or double transection and following either isolation or removal of a 50 cm jejunal loop. 2. In the fasted dog, the activity was characterized by the propagation of myoelectric complexes at a velocity of 4 cm/min during which the mean transit time averaged 13 min/m. About 2/3 of these complexes were seen to pass beyond a single section and anastomosis of the jejunum with a delay of 15 min. This number was reduced to 1/3 and the delay doubled when a second section was performed 50 cm distally. 3. In dog with an isolated jejunal loop, most of the myo-electric complexes were seen to pass from the proximal intestine to the loop and then to the intestine beyond the sit of anastomosis within 37 min. Some complexes however passed directly through the anastomosis within 30-32 min, affecting or not the loop. Others started on the loop and/or on the intestine beyond the anastomosis. Finally, the total number of complexes recorded on the distal jejunum was greater than on the duodenum, an effect which disappeared after removal of the isolated loop. 4. The propagation of the complexes occurred at a lower velocity after denervation of a jejunal segment in situ but was arrested in the case of an isolated-denervated jejunal loop. 5. It is concluded that continuity of structures in the bowel is essential for the propagation of a myo-electric complex which is stopped and replaced by another complex at the level of an anastomosis, the number os complexes reorganized beyond an anastomosis and their velocity of propagation depending upon both intrinsic and extrinsic neural influences.


The recovery heat production in non-myelinated garfish olfactory nerve fibres. 1. The recovery heat production of the non-myelinated fibres of garfish olfactory nerve has been measured. 2. At about 20 degrees C the total recovery heat was 381 +/- 26 microcal g-1 impulse-1 at a stimulation frequency of 2 sec-1. 3. The time constant of decay of the recovery heat production after a brief period of stimulation was 78.7 +/- 3.1 sec at about 20 degrees C. 4. Changing the temperature (by +/- 5 degress C) had little effect on the total recovery heat produced. 5. However, lowering the temperature reduced both the rate of rise, and the maximum rate of recovery heat production whereas the time constant of decay was increased. Raising the temperature produced corresponding changes in the opposite direction. 6. the recovery heat production measured in the present experiments is consistent with the previously measured oxygen consumption in the same preparation.


A comparison between the discharges of human nociceptive nerve fibres and the subject's ratings of his sensations. 1. Impulses in cutaneous nerve fibres were recorded percutaneously with tungsten micro-electrodes from the superficial radial nerve of adult human subjects. 2. Eight units studied had conduction velocities below 1.5 m/sec, and thus belong to the class of C fibres. On the basis of their responsiveness to mechanical and to thermal stimuli the units were classified as 'polymodal nociceptors'. 3. Units were tested with 12 sec heat pulses starting from a base line temperature of 43.0-43.5 degrees C. Heat stimuli reaching three different maximal levels were applied in randomized order, the subjects being blind with respect to stimulus size. Each of the eight units studied was tested with more tha 20 stimuli and with four of them were 80-125 stimulus repetitions. 4. After each stimulus the subjects had to rate his sensations on a six-point rating scale extending from 'just noticeable' to 'very hot, painful'. 5. Discrimination between the three stimulus levels by the integtated spike discharges and by the ratings of the subject was compared using the P(A) measure of the Signal Detection Theory. It was found that both the neurophysiological and the psychophysical measurements provided about equal discrimination. 6. In addition it has been found that spike discharges and ratings share a common variance beyond their common dependence on the stimulus level. Among the factors contributing to this interdependence a 'temporal position effect' was the most significant. 7. In spite of this interdependence between discharge rates and subjective ratings, the latter gave a better estimation of the stimulus size than of the discharge rates of the individual C fibre under study. 8. It was concluded that the polymodal C-nociceptors might be instrumental for the quantitative aspects of heat pain sensation. The hypothesis was derived from the present results that, under the conditions of cour experiments, the loss of information in the course of central processing might be about equal to the gain by the parallel processing in a population of nociceptors excited by a stimulus.


Studies of the development of brain barrier systems to lipid insoluble molecules in fetal sheep. 1. The development of the blood-brain and blood-c.s.f barriers to lipid insoluble substances of different molecular radii has been studied in fetal sheep, early (60 days) and late (125 days) in gestation, using labelled erythritol (C14), sucrose (3H or 14C), inulin (3H or 14C) and albumin (125I), or albumin and IgG detected by immunoassay. 2. Morphological studies of fetal brain and choroid plexus at the same gestational stages were carried out using thin section electron microscopy and the freeze fracture techniques. 3. Penetration of markers into c.s.f. was substantially greater at 60 days than at 125 days, but at both ages the steady-state level achieved appeared to be related to molecular size. 4. A simple model describing penetration from blood into c.s.f. at 60 days is proposed. It involves the assumption that c.s.f. and brain extracellular fluid are effectively separate compartments; morphological and permeability data which supports this assumption is presented. The data for c.s.f. at 60 days are consistent with the suggestion that the markers penetrate into c.s.f. by diffusion and are not restricted by small pores in the interface between blood and c.s.f. 5. The reduction in penetration which occurred by 125 days for all markers except erythritol appears to be accounted for by an increase in the sink effect and a decrease in the effective surface area for exchange between blood and c.s.f. 6. Intercellular tight junctions of both cerebral endothelial cells and choroid plexus epithelial cells were well formed at 60 days gestation. There was no change in junctional characteristics previously thought to correlate with transepithelial permeability (tight junction depth and strand number) between the two ages studied, although there were marked changes in permeability. 7. Evidence is advanced in support of the hypothesis that in the fetus much of the penetration of lipid insoluble non-polar substances across the blood-c.s.f. barrier and perhaps across the blood-brain barrier occurs via a transcellular route consisting of a system of tubulo-cisternal endoplasmic reticulum. Penetration via the choroid plexus appears to be the dominant route for penetration from blood into c.s.f. in the 60 day fetus.


Responses in the diagonal band of Broca evoked by stimulation of the fornix in the cat. 1. Field potentials were recorded within the boundaries of the septal component of the diagonal band of Broca following stimulation of the fornix. The position of the recording electrode was marked by pressure injection of Alcian blue dye. 2. Stimulation of the medial aspect of the ipsilateral fornix produced a simple field caudally consisting of a short duration, short latency negative wave (N1) and a later small prolonged positive wave (P1). It is suggested that N1 is due to antidromic activation of the cells and P1 to their recurrent inhibition. 3. In the rostral part of the septal component of the diagonal band of Broca the field pattern was more complex, containing, in addition to N1 and P1, further negative waves, N2 and N3. N2 was compounded of antidromically and synaptically evoked components and N3 was associated with monosynaptic excitation of the cells. 4. Stimulation of the lateral margin of the fornix was shown to excite antidromically and synaptically the same cells as were excited by stimulation of the medial aspect of the fornix. 5. Stimulation of the medial and lateral aspects of contralateral fornix generated positive waves of similar character to P1. 6. Intracarotid injection of hyperosmotic saline solution caused behavioural signs of arousal and inhibition of spontaneous discharge in a third of the units tested. Spontaneously discharging units (mean frequency +/- S.E. of mean, 13.4 +/- 1.8, n = 55) were inhibited by stimulation of the medial and lateral ipsilateral and contralateral fornix. It is suggested that inhibitory interneurones receive contra- and ipsilateral input. Units with these characteristics were found. 7. The septal component of the diagonal band of Broca was compared with other septal nuclei and found to resemble them in its rostral portion in that it has a reciprocal relationship with ventral and dorsal hippocampus. The caudal portion is unique in the cells project to dorsal and ventral hippocampus but there is no reciprocal projection.


The calcium action potential and a prolonged calcium dependent after-hyperpolarization in mouse neuroblastoma cells. 1. Action potentials elicited in solutions with elevated [Ca2+] (1.8-40 mM) have been studied in differentiated cells of mouse neuroblastoma clone N1E-115 in tissue culture. 2. The action potential in high [Ca2+] solutions containing eithr Na+ or Tris is followed by a prolonged after-hyperpolarization (a.h.p.) lasting 0.5-4 sec. The a.h.p. reverses sign between -75 and -85 mV. 3. Externally applied tetraethylammonium (TEA, 15 mM) increases the Ca2+ spike overshoot, prolongs the falling phase and enhances the a.h.p. duration. The a.h.p. is inhibited by Ca2+ antagonists such as La3+, Co2+ and Mn2+. 4. After replacement of Ca2+ by Ba+ or Sr2+ (20mM) action potentials can still be elicited in Na+-free solution, but no a.h.p. is observed. 5. Increasing [Ca2+] from 1.8 up to 20 mM results in an increased capability of neuroblastoma cells to fire repetitively and in a consistent reduction of the firing rate from about 4-10 sec-1 to 0.5-1.8 sec-1. 6. It is concluded that Ca2+ entry during the action potential activates a TEA-resistant K+ conductance which gives rise to the prolonged a.h.p. Data from repetitively firing cells are consistent with the view that the a.h.p. plays a role in the regulation of low-frequency firing.


The calcium current and the activation of a slow potassium conductance in voltage-clamped mouse neuroblastoma cells. 1. The Ca2+ inward current (ICa) and a slow outward current in differentiated cells of mouse neuroblastoma clone N1E-115 have been studied under voltage-clamp conditions. 2. ICa shows voltage- and time-dependent inactivation when evoked by step-wise depolarizations in Na+-free solution containing high [Ca2+] (20 nM) and tetraethylammonium (TEA, 25 mM). Ba2+ and Sr2+ can substitute for Ca2+. 3. Holding potentials below -70 mV maximal activate ICa. Half inactivation occurs at -56 mV and ICa is completely inactivated beyond holding levels of -30 mV. Maximum peak currents are of the order of 10(-4) A/cm2 and the reversal potential ranges from +40 to +60 mV. The ICa inactivation time course follows first-order kinetics with a voltage-depedent time constant ranging from 25 to 100 msec. 4. The striking resemblance between ICa and the Ca2+ current in the unfertilized mouse oocyte (Okamoto, Takahashi & Yamashita, 1977) is discussed. 5. A slow outward current with a rise time of several seconds is recorded on voltage steps beyond -20 mV in high [Ca2+] solutions. It is carried primarily by K+ on account of the value of the reversal potential and its dependence on [K]0. This K+ current is TEA-insensitive and is blocked by Ca2+ antagonists. 6. The slow K+ current (IK(Ca)) is suggested to be mediated by Ca2+ influx, but the voltage-dependence of the underlying conductance (GK(Ca)) differs significantly from the ICa voltage-dependence. 7. The results are consistent with the hypothesis that IK(Ca) depends both on ICa and on membrane potential. An alternative hypothesis is briefly discussed.


Two-carrier influx of neutral amino acids into rabbit ileal mucosa. 1. The influx of serine, alanine and methionine across the brush border membrane of the rabbit ileal mucosa has been measured during short periods of incubation. 2. A kinetic analysis of the uptake data, assuming one mediated entry mechanism or one mediated entry mechanism plus a diffusion component to be present, does not provide an adequate explanation for the results obtained. Methionine inhibition of serine uptake provided direct evidence that the diffusive entry of serine into the rabbit ileum was small or non-existent. 3. Data taken from amino acid inhibition and substrate-uptake experiments, fitted simultaneously to a double hyperbolic model of amino acid uptake, give good agreement between predicted and experimental results. There is also good quantitative agreement between computer-derived kinetic constants in the present work and similar constants obtained previously using a different method of analysis. 4. Present work supports the general hypothesis that neutral amino acids use two mediated pathways to enter the rabbit ileal mucosa. The possible physiological significance of these results and their probable effect on currently held concepts of how amino acids cross the brush border membrane of the rabbit intestinal mucosa is discussed.


Effects of atropine on secretion and motility in isolated gastric mucosa and attached muscularis externa from ferret and cat. 1. A combined in vitro preparation of gastric mucosa and adjacent muscle from young ferrets and kittens has been used to study the effects of atropine on acid secretion and motility produced by acetylcholine (ACh) and pentagastrin.2. The minimal dose of atropine required to abolish a maximum secretory response to ACh also prevented the associated motility response. This dose of atropine also blocked the motility response to pentagastrin, but was without influence on the secretory effect of this agent. A 10(3) times larger dose of atropine reduced the secretory effect of pentagastrin by half, probably not by anti-muscarinic effect. The results exclude the possibility that the acid secretory response to pentagastrin necessarily involves a cholinergic receptor.3. The results support the view that the response of the fundic smooth muscle to pentagastrin depends on the excitation of cholinergic nerves.4. No evidence has been found of any cholinergic component in the acid secretory response to pentagastrin. In assessing the significance of this result, however, it must be remembered that the Auerbach plexus has been removed over the major part of the mucosa, and the Meissner plexus deprived of input and probably damaged.5. The results are compatible with the hypothesis that the depressant effect of atropine on acid secretion produced by gastrin and its derivatives is due to the elimination of a cholinergic potentiating influence arising in the intramural plexuses. The residual Meissner plexus elements in this in vitro preparation appear inadequate to sustain this effect.


Influence of potassium, sodium, perfusion pressure, and isoprenaline on renin release induced by acute calcium deprivation. 1. These studies were conducted in isolated perfused rat kidneys to determine the influence of perfusion pressure, isoprenaline, K, and Na on renin release stimulated by acute Ca deprivation.2. Removing Ca from the perfusion medium for 10 min stimulated renin release and reintroducing Ca returned it toward control values.3. Lowering concentration of Ca in the perfusion medium from 5 to 0 mM increased the effectiveness of low perfusion pressure (50 mmHg) and isoprenaline (2.43 muM) in stimulating renin release.4. At higher perfusion pressure (150 mmHg), renin release was inhibited in perfusion medium containing 2.5 mM-Ca but not in medium containing no Ca. In fact, high perfusion pressure stimulated renin release when the perfusion medium was without Ca.5. Raising concentration of K in the perfusion medium partially inhibited the renin release induced by Ca deprivation. Adding 5 mM-EGTA to Ca-deprived medium stimulated a greater rate of renin release than that of Ca-deprived medium alone. This greater renin release was also partially inhibited by raising K concentration in the perfusion medium.6. Lowering concentration of Na in the perfusion medium from 145 to 25 mM partially inhibited the renin release induced by Ca deprivation in the presence of low perfusion pressure or isoprenaline.7. These findings support the hypothesis that a decreased concentration of Ca in the cytoplasm of the juxtaglomerular cell stimulates renin release and increased Ca inhibits renin release. The sequence of events which leads to changes in cytoplasmic Ca might depend on the concentration of Ca in the perfusion medium, the renal perfusion pressure, the membrane potential of the juxtaglomerular cells, and Ca-Na exchange mechanisms.


Influence of potassium, sodium, calcium, perfusion pressure, and isoprenaline on renin release induced by high concentrations of magnesium. 1. These studies were conducted on isolated, perfused rat kidneys to determine the mechanism through which high concentrations of extracellular Mg (20mM) stimulated renin release. 2. Raising K concentrations in the perfusion fluid from 5 to 50 mM, and raising renal perfusion pressure from 100 to 150 mmHg inhibited the renin release induced by 20 mM-Mg. The response was reversible. 3. Renin release induced by low renal perfusion pressure (50 mmHg) or isoprenaline (2.43 microM) was unaffected by 20 mM-Mg. However, this release was augmented when 5 mM-Ca was added in conjunction with 20 mM-Mg. 4. In medium containing 20 mM-Mg, lowering Na concentration from 145 to 100 mM augmented the renin release induced by low perfusion pressure and isoprenaline. Further lowering Na to 25 mM had no additional effect. 5. It is concluded that 20 mM-Mg activates renin release by a mechanism which involves hyperpolarization of the juxtaglomerular cell membrane and an associated decrease in cytoplasmic Ca. Such a mechanism might be coupled to a Mg-Na exchange pump.


Diaphragmatic and oesophageal activity in regurgitation in sheep: an electromyographic study. 1. Electromyographic (e.m.g.) recordings of reactions of the oesophagus, vertebral and costal fibres of the diaphragm and from the reticulum-one of the cranial divisions of the stomach were made during the regurgitation of rumination in sheep. 2. E.m.g.s indicated that a contraction of the caudal thoracic oesophagus developed over a period of about 2 sec before, and ceased at the time of, the more forceful inspiratory effort associated with regurgitation. 3. This contraction was confined to the caudal region of the thoracic oesophagus in which it was characteristically more prolonged and intense in its most caudal part within 15-25 mm of the hiatus oesophageus. It is interpreted to contribute to development or intensification of a caudal thoracic oesophageal sphincter. 4. The more forceful inspiratory effort at the time of regurgitation was due to costal fibres of the diaphragm. Although active normally during inspiration the vertebral fibres of the hiatus oesophageus do not contribute to this more forceful inspiration. This may facilitate regurgitation of digesta. Similarly, inactivity of vertebral but not costal fibres detected during primary oesophageal contractions (of swallowing) may make for easier passage of digesta into the stomach.


Plasma volume shifts during moderate exercise in splenectomized greyhounds. 1. Plasma volume was measured in splenectomized greyhounds, using T-1824, and sequential changes in plasma volume were measured using two independent methods, based on T-1824 plasma decay characteristics and on changes in haematocrit. 2. There were no significant differences between estimates of plasma volume made by the two methods in resting or exercising dogs. Therefore it was concluded that the characteristics of the decay of dye concentration in plasma were not affected by exercise and that sequential determinations of plasma volume from a single dye injection provide a valid determination of plasma volume during exercise in dogs. 3. During submaximal exercise, the plasma volume increased by 0-11.8% of its initial value. In no case did plasma volume decrease significantly. 4. An increase in plasma volume during excercise was also seen in animals previously made acutely hypervolemic or hypovolemic. 5. It is suggested that the increase in plasma volume constitutes part of a mechanism maintaining oxygen delivery to tissues during exercise.


Sodium, potassium and water metabolism in the rabbit: the effect of sodium depletion and repletion. 1. Dietary sodium depletion and subsequent repletion was studied in rabbits. Potassium intake was maintained constant. 2. during sodium depletion and repletion blood pressure, packed cell volume, food consumption and body weight remained at control values. 3. Decreased sodium excretion was observed in both urine and faeces during sodium depletion and the physiological control of these changes is discussed in relation to the renin-angiotensin-aldosterone system. 4. Potassium excretion during sodium depletion initially fell as a result of reduced urine volume and gradually returned to normal. Urine potassium concentration remained constant. 5. Faecal excretion of potassium rose by 63% during sodium depletion and there was a rise from a control value of 17-25% in the proportion of total potassium excretion accounted for by the faecal component. 6. Water consumption and urine volume both decreased in the initial phase of sodium depletion and then returned to control levels. 7. It is important to consider both urinary and faecal excretion of sodium and potassium when calculating balance status for either ion. Faecal excretion, as well as kidney function, shows important physiological adaptations.


Plasma active and inactive renin in the rabbit: effect of dietary sodium depletion and repletion. 1. Active and acid-activatable (inactive) renins were measured in rabbit plasma under control conditions and during sodium depletion with subsequent repletion. 2. Active renin increased by 97% during sodium depletion and returned to control levels on repletion. Both changes were complete within 1 day of changing the diet. 3. During dietary sodium depletion inactive renin levels initially fell to zero and then increased until, after 13 days, inactive renin was again 10% of total renin levels, a proportion comparable to the control values. 4. Sodium repletion caused plasma inactive renin to return to control levels over about 13 days, a quite different time course to active renin. Therefore, in the first phase of repletion the proportion of total renin in the inactive form rose to 19%. 5. These changes are discussed in relation to concurrent changes in sodium, potassium and water metabolism.


Receptive fields of fibres in the central ends of divided dorsal roots. 1. Action potentials were recorded from single fibres in the central ends of divided lumbar dorsal root filaments in anaesthetized cats. 2. Six classes of receptive field could be identified in such fibres, which corresponded very closely to the receptive fields of single primary afferent fibres. 3. For fibres with superficial receptive fileds (cutaneous or hair), a percutaneous electrical stimulation was used to drive the afferents at sustained high frequencies (100, 200 or 300 Hz), and the ability of the recorded fibre to follow the stimulation monitored. About one half of fibres with superficial receptive fields could be driven at sustained high frequencies. 4. The shape of the action potential from the fibre was analysed at different distances from the spinal cord. Close to the spinal cord a clear action potential could be recorded, but further out along the filament the action potential was often attenuated or absent. 5. It is suggested that some at least of these fibres are recurrent collaterals of primary afferent fibres, that taper in size after leaving the spinal cord. The function of such fibres is discussed.


Air humidity and carotid rete function in thermoregulation of the goat. 1. The effects of air humidity on respiratory rate have been studied in conscious goats exposed to an air temperature of + 33 degrees C. Before the experiments the animals had been chronically implanted with hypothalamic thermodes and intravascular heat exchangers to manipulate hypothalamic and general body core temperatures.2. Raising air humidity from 37 to 96% at constant air temperature resulted in a rise of respiratory rate, an immediate increase in hypothalamic temperature and a delayed smaller increase in general body core temperature.3. The rise of respiratory rate was smaller when general body core temperature was clamped at its control level and was absent when hypothalamic and general body core temperatures were clamped at their control levels during the humid air phase.4. It is concluded that the effect of high air humidity on respiratory rate in goats is predominantly the result of a rise in hypothalamic temperature acting on local thermosensitive structures. The carotid rete heat exchanger is thought to provide the thermal link between the evaporating surfaces of the upper respiratory tract and the hypothalamus.5. This function of the carotid rete heat exchanger is restricted to heat stressed animals. In animals subject to central cooling no local effects on hypothalamic temperature could be observed when the temperature of the inspired air was altered from + 33 to - 17 degrees C.


Post-natal development of amiloride sensitive sodium transport in pig distal colon. 1. Both electrophysiological properties and unidirectional Na and Cl fluxes have been determined across distal colons taken from pigs during early post-natal development. 2. The transmural potential difference (Vms) was 5 mV in the new-born and 10 mV in the 4 day old colon. The short circuit current (Scc) showed a three to sixfold increase during the first 10 days of post-natal life. The microvillar membrane potential (Vm) fell from about -45 mV in the new-born to -40 mV in the 4 day old colon. 3. Amiloride had no effect on Vms, Scc or Vm, measured in the new-born animal. It reduced Vms and Scc, caused a hyperpolarization of Vm and increased the microvillar membrane/basolateral membrane resistance ratio (Rm/Rs) in colons taken from older animals. 4. The Scc of distal colons taken from new-born and 1 day old pigs was only half that predicted from unidirectional measurements of Na flux. This discrepancy, which could not be completely accounted for by net CL absorption, disappeared in the older animals. 5. Net transport of Na doubled during the first 24 h of post-natal life. Part of this transport took place through an amiloride sensitive, non-electrogenic, pathway. 6. It is suggested that Na uses mainly a non-electrogenic pathway to cross the mucosa of the new-born pig. This pathway is replaced by an electrogenic amiloride sensitive mechanism in older animals. Aldosterone is thought to initiate these changes in Na tranport.


Aldosterone induced changes in colonic sodium transport occurring naturally during development in the neonatal pig. 1. Serum concentrations of aldosterone in later fetal, 3-6 week old and adult pigs are of the order of 300 pg ml.-1. This increases to about 2000 pg ml.-1 in the period immediately after birth. 2. Canrenoate injected into pigs from birth onwards stops the increase in colonic short-circuit current, seen to take place normally during early postnatal development. Amiloride has little or no effect on the short-circuit current of colons taken from canrenoate injected pigs. 3. Canrenoate stops the post-natal increase in colonic Na influx (and therefore net transport) seen to occur under normal conditions. 4. There is in the neonatal pig distal colon a portion of Na transport which appears to be resistant to inhibition by amiloride or canrenoate. 5. There is a second portion of Na transport, increasing in importance as the piglets become older, which is electrogenic and which is electrogenic and which is inhibited by prior injection of canrenoate. It is assumed that this fraction of Na transport is influenced by aldosterone. 6. There is a third part of Na transport, maximal in colons taken from one day old animals, which appears to be non-electrogenic. This is also blocked by prior injection of canrenoate. 7. The physiological relevance of these findings is discussed.


The effect of hyperosmolarity and insulin on resting tension and calcium fluxes in rat soleus muscle. 1. The effect of hyperosmolarity on resting tension and on the fluxes of Na and Ca has been characterized in isolated soleus muscles of the rat. 2. When the osmolarity of the incubation medium was increased by the addition of non-permeant solutes (100-400 m-osmole), the tension showed a rapid dos-dependent rise which could be maintained for up to 60 min. 3. Tension development was unaffected by tubocurarine (2 X 10(-5) M), considerably diminished by the omission of Na or Ca from the incubation medium, and inhibited by tetracaine (10(-4) M). 4. The addition of mannitol or sucrose (200 mM) induced a prompt stimulation of the influx of 22Na and 45Ca. Both in the absence and the presence of extracellular Ca hyperosmolarity stimulated the washout of 45Ca from preloaded muscles. Tetracaine (5 X 10(-4 M) suppressed the effects of hyperosmolarity on both the influx and the efflux of 45Ca, but only gave a modest reduction in the stimulation of 22Na influx. 5. Insulin (5-100 mu./ml.) induced a considerable further rise in the resting tension of muscles exposed to mannitol or sucrose (200 mM). This effect was seen in a glucose-free medium and could be abolished by the addition of insulin antibody. 6. It is concluded that hyperosmolarity leads to a rise in the concentration of free Ca2+ ions in the sarcoplasm, partly due to a mobilization of Ca from intracellular pools, but to a considerable extent supplemented from extracelluar sources. Under these conditions, insulin further augments the Ca2+ ion level in the cytoplasm.


Subject instruction and long latency reflex responses to muscle stretch. 1. Surface electromyographic recordings were made in eight normal subjects from the isometrically contracting elbow flexors before and during forcible extension of the elbow through 7 degrees in 50-150 msec. 2. Weh the subjects were instructed prior (2-5 sec) to a forthcoming stretch to 'resist' or to 'let go', they could reliably enhance or suppress e.m.g. activity occurring between 40 and 70 msec from commencement of the stretch. Such e.m.g. activity represents a 'long-latency' (or 'M2') reflex response: it occurs with a latency longer than the spinal segmental monosynaptic reflex, but shorter than a voluntary reaction time. When the subjects were given their instructions (by means of a light) at the moment the stretch commenced, however, none of them could adjust the long-latency reflex appropriately. 3. It is concluded that central, evaluative processes commencing at the time of a perturbation cannot influence long-latency reflex responses to that perturbation.


The effect of hypothalamic lesions on immuno-reactive alpha-melanocyte stimulating hormone secretion in the rat. We have examined the hypothesis that MSH secretion in the rat is under a tonic inhibitory control by the central nervous system. Electrothermic lesions were made in the medio-basal hypothalamus (m.b.h.) which destroyed the hypothalamo-hypophyseal connexions. Plasma and pituitary alpha-MSH wwere measured using a sensitive and specific radioimmunoassay technique. Pituitary alpha-MSH content decreased to 17% of control levels 24 hr after the lesion and returned to normal by 7 days. Plasma alpha-MSH was maximally elevated 15 min after the lesion, and returned to normal by 2 hr. No further change over control levels was found for the remainder of the experiment (98 days). The similarity of the plasma alpha-MSH response after m.b.h. lesions to that found previously after administration of long acting dopamine receptor blocking drugs suggests that these lesions may interrupt impulse flow in dopaminergic tubero hypophyseal neurones which are thought to be important in the inhibitory control of MSH secretion in the rat. From our present results it seems that the rat pituitary, unlike that of lower vertebrates, is able to re-establish basal MSH secretion very quickly after disconnexion from central control.


On the purpose of selective innervation of guinea-pig superior cervical ganglion cells. Preganglionic axons arising from different levels of the mammalian spinal cord make preferential connexions with different classes of superior cervical ganglion cells (Langley, 1892, 1900; Njå & Purves, 1977a). For example, preganglionic axons from the first thoracic segment (T1) make relatively strong connexions with ganglion cells activating end-organs of the eye; conversely, axons arising from T4 selectively innervate ganglion cells projecting to the ear. In the present work we have asked whether this selectivity reflects the function of the pre- and post-synaptic cells, and aspect of their respective positions, or some other criterion. 1. End-organs with different functions at the same locus (the eye) respond to stimulation of the same ventral roots; end-organs of a single modality (hairs or blood vessels) at different positions, however, tend to be activated by different spinal segments. Thus the segmental innervation of ganglion cells is correlated with the position rather than the function of post-ganglionic targets. 2. The role of target position in ganglion cell innervation was examined directly by recording from neurones sending axons to different destinations. Superior cervical ganglion cells running dorso-medially in a spinal nerve receive, on average, innervation from more caudal segments than cells projecting ventro-laterally. 3. These selective connexions do not depend on intraganglionic cell position: neurones located at different points along the major axes of the superior cervical ganglion receive, on average, the same segmental innervation. In accord with this observation, retrogradely labelled neurones innervating a particular target such as the eye or ear are widely and randomly distributed within a large portion of the ganglion. Thus the importance of post-ganglionic target position in ganglion cell innervation is not simply a reflexion of ganglionic topography. 4. We conclude that one purpose of the selective connexions in the superior cervical ganglion is to bring together preganglionic axons arising from different levels of the spinal cord and ganglion cells whose axons innervate particular regions of the superior cervical territory.


The function of the sodium pump during differentiation of amphibian embryonic neurones. 1. A method has been developed for studying the differentiation in tissue culture of ectoderm and mesoderm derivatives, dissected from amphibian embryos which have just completed neurulation. 2. Neurones, striated muscle cells and pigment cells, together with other unidentifiable cell types, differentiated as a monolayer with approximately the same time course as in the whole embryo. The proportion of different cell types in the cultures was measured quantitatively by cell counting. 3. Treatment of embryos during neurulation with the cardiac glycoside strophanthidin reduced the number of neurones which subsequently differentiated in culture. Other cell types were not affected. 4. The relationship between inhibition of neural differentiation and strophanthidin concentration was sigmoid, with maximum inhibition at 10(-5) M-strophanthidin and the mid-point at 5 X 10(-7) M-strophanthidin. 35% of neurones differentiating in culture were not affected by glycoside treatment. 5. The glycoside hexahydroscillaren A had no effect on neural differentiation. 6. Increasing extracellular potassium to 100 nM during strophanthidin treatment completely protected differentiating neurones from the inhibitory effect of strophanthidin. 7. Treatment of embryos with 100 mM-KCl during neurulation had no effect on the subsequent differentiation of neurones. 8. Treatment of cultures with an antibody to mouse salivary gland Nerve Growth Factor reduced the number of neurones by 30%. 9. Exposure to strophanthidin while the embryo moved from the early neural fold stage to the late neural fold stage was as effective in reducing subsequent neural differentiation as treatment throughout neurulation. 10. The proportion of nerve cells in the cultures was not affected if strophanthidin treatment ended before the early neural fold stage or did not begin until the late neural fold stage. 11. Embryos treated with strophanthidin during neurulation and then allowed to grow into tadpoles developed abnormal nervous systems. 10(-6) M-strophanthidin had little effect on the volume of grey matter, but reduced the white matter by 50%. 12. The results are consistent with the view that strophanthidin achieves its effect on neural differentiation by inhibiting the sodium pump. They are discussed in the light of the suggestion that activation of the sodium pump is an essential part of nerual differentiation.


Rhabdospora thelohani Laguessé, 1895 (Apicomplexa): new host and geographic records with taxonomic considerations. New fish species and geographic records for Rhabdospora thelohani Laguessé, 1895 (rodlet cells) are presented. Additionally, the ultrastructure of R. thelohani in Alburnoides bipunctatus ohridanus Karaman, Borostomias antarcticus (Lönnberg), Leuciscus cephalus albus Bonaparte and Rutilus rubilio (Bonaparte) is compared with that reported by other authors and with members of Subphylum Apicomplexa. The ultrastructure of R. thelohani was similar in all the fish species examined; however, the organism was not present in all members of any single species and had intertissue density variations. Rhabdospora thelohani is pyriform, averaging in size 7 X 12 micrometer, with a basal nucleus. The surface complex is composed of a layer (0.5 micrometer diameter) formed by microfilaments (9.3 nm) and an outer trilaminar membrane (9.3 nm). The cytoplasm contains structures identical to rhoptries, micronemes and subpellicular microtubules. Mitochondria, Golgi apparatus, and rough endoplasmic reticulum were not observed, althouth free ribosomes were present and arranged in a vesicular pattern. The observations suggest that the organism moves between cell of epithelial layers and is either released into a lumen intact or passively or actively discharges its contents into a lumen. Results from this study indicate that R. thelohani should be considered a member of Apicomplexa unless definitive evidence is presented to the contrary.


Temperature-sensitive Chlamydomonas mutants manifesting flagellar regression at a restrictive temperature. The regeneration kinetics of Chlamydomonas reinhardtii mutants TS-6 and TS-79, whose flagella were mechanically amputated, indicated that the flagellar precursor in cytoplasm was used for regeneration when cycloheximide was present. The TS-6 cells rendered nonflagellate by regression at 35 C did not regenerate in the presence of cycloheximide, indicating that the precursor was inactivated by the high temperature. Neither mutant was able to use the absorbed flagellar components for regeneration in the presence of cycloheximide.


Selection of nonmotile Tetrahymena with Ficoll underlayers. The mechanisms regulating the development of cilia in Tetrahymena are poorly understood but might be revealed through the study of ciliogenesis mutants. Failure to regenerate cilia after dibucaine deciliation results in continued absence of motility. Therefore, to isolate ciliogenesis mutants efficiently, methods for separating motile and nonmotile cells are essential. We examined the efficacy of Ficoll underlayers for these separations. Ciliates of T. thng type IV) were mixed with Ficoll and added as underlayers to separatory funnels containing growth medium. At 27 C most of the cells remained motile and were found in the top layer; at 37 C, there was a time-dependent increase in the number of nonmotile cells and the number of cells in the Ficoll layer. After 150 min at 37 C, most of the cells became nonmotile and were found in the Ficoll layer. Other studies indicated that at 37 C, the cells remained alive and capable of regenerating cilia when deciliated. Thus, it is clear that the Ficoll underlayer effectively separates the majority of nonmotile cells from the majority of motile cells. Evidently, however, at 37 C wild-type T. thermophila exhibit temperature-sensitive phenotypic variability with regard to motility which should be minimized when selecting for mutations affecting motility and ciliogenesis.


Studies on a morphologically distinct colchicine-resistance variant of Entamoeba sp. Colchicine has a temperature-dependent cytotoxic effect on Entamoeba sp. (Laredo isolate) that is most apparent when the drug is applied during the initiation of cultures at a concentration of 7.5 mM or higher. Continued transfer of cultures in medium containing progressively increasing concentrations of colchicine has resulted in a variant that grows prolifically in the presence of colchicine (7.5 mM) with a generation time comparable to that of the parent stock, Comparison of a number of parameters of the 2 variants revealed that colchicine resistance was accompanied by a change in cell shape, a reduced membrane permeability, which could partially be overcome by the addition of dimethyl sulfoxide (DMSO), and a reduced tolerance to osmotic stress. However, the parent strain and resistant variant were equally susceptible to cycloheximide and puromycin suggesting that the acquired colchicine resistance may not be explained on the basis of an entirely unspecific generalized reduced ability for drug uptake. Colchicine resistance and altered structure were found to be stable over a long period of time. The possible interdependence of these 2 parameters and their relation to cell motility in Entamoeba sp. are discussed.


An investigation of the route and progression of Encephalitozoon cuniculi infection in adult rabbits. Rabbits infected either orally or intratracheally with cell culture-grown Encephalitozoon cuniculi were monitored regularly for serum antibody levels and E. cuniculi in the urine. Their responses were compared with intravenously inoculated and uninoculated control rabbits. All rabbits receiving E. cuniculi developed serum antibodies, generally within 3 weeks, and excreted E. cuniculi by 6 weeks. In the acute stage of infection, the organs most affected were lung, kidney and liver; the brain and gut were unaffected. However, during chronic infection, the brain, kidney, and heart were the only organs found to be involved. Antibody levels were very high at this stage. Thus both the oral and tracheal routes may be normal routes of infection with E. cuniculi in adult rabbits.


Transport of L-proline and its regulation in Leishmania tropica promastigotes. Leishmania tropica promastigotes transport L-proline through an active uptake system that has saturation kinetics, temperature dependence, a requirement for metabolic energy and transport against a concentration gradient. In experiments lasting 10 min, less than 10% of the proline transported is incorporated into macromolecules. The remainder is largely unaltered proline with an intracellular concentration nearly 60 times that in the reaction mixture. The uptake system has a relatively broad specificty; it is competitively inhibited by D-proline as well as by alanine, methionine, valine, azetidine-2-carboxylate, thioproline, 3,4-dehydropoline, hydroxyproline and alpha-aminoisobutyric acid. Pre-established intracellular proline pools exchange with external proline as well as compounds that compete with it for uptake. Evidence is presented that feedback inhibition and transinhibition may regulate proline uptake in this organism.


DNA-dependent RNA polymerase III from Acanthamoeba castellanii: comparison of the catalytic properties of the trophozoite and cyst enzymes. DNA-dependent RNA polymerase III was partially purified from trophozoites and immature cysts of the small soil ameba, Acanthamoeba castellanii. In contrast to the active modulation of the variety of transfer RNA species which are transcribed during encystment, no difference was found in the chromatographic or catalytic properties of the enzyme responsible for their transcription.


Use of situational cues by preschool children. Pictures often are used in language intervention programs to elicit selected linguistic constructions or to teach concepts to children below the age of 5 years. However,, preschool children frequently are egocentric in their perceptions and in their language, and are unable to view a situation from a perspective other than their own. This study presented children who were in Piaget's preoperational period of development with pictures accompanied by a one-word descriptive phrase and asked the children to explain what was meant by the utterance. It was found that the younger child generally was more egocentric in his interpretations, and his responses reflected less attention to the situational cues present in the picture. The results are discussed in light of common clinical practices of using pictorial stimuli for children with language problems.