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Biomedical subjects

B H Natelson

Publications and source records attributed to B H Natelson.

At least 163 records · Page 9Linked to original sources
PubMed1980

A role for environmental factors in the production of digitalis toxicity.

The purpose of our study was to learn whether changes in the external milieu could affect the lethality of ouabain. We found that guinea pigs experiencing restraint stress for the first time showed a greater susceptibility to the lethal effects of ouabain (175 microgram/kg IP) than non-stressed controls. Adaptation to the restraint procedure abolished this sensitization. This effect related to repeated experience with restraint and not to repeated human handling because repeatedly handled guinea pigs still showed sensitization to the lethal effect of ouabain (200 microgram/kg IP) when restrained for the first time. These data indicate that environmental factors will have to be considered in addition to changes in the internal milieu when trying to explain individual differences in sensitivity to toxicity while taking constant doses of digitalis.

Animals↗
PubMed1980

The relation of plasma norepinephrine and epinephrine levels over time in humans.

Plasma norepinephrine (NE) and epinephrine (E) levels were measured at 15 min intervals in 5 male and 7 female, healthy recumbent humans over periods of 4 h (n = 9), or 8 h (n = 3). Levels of both plasma catecholamines (CA) fluctuated both tonically and phasically over time. There was a pronounced downward ("tonic") trend in the levels of the 4 h subjects who had slept at home but no consistent trend was seen in the 8 h subjects who slept in the test bed overnight. The average (+/- S.E.) of median plasma NE levels was significantly lower (231.9 +/- 15.0 pg/ml) in the 4 h group than the 8 h group (356.9 +/- 6.7 pg/ml) probably due to the younger age of the 4 h group and the weakly positive correlation of NE levels with age. Plasma E levels showed no correlation with age and were not significantly different in the 4 h (111.6 +/- 27.0 pg/ml) or 8 h (98.2 +/- 13.7 pg/ml) groups. NE and E levels correlated well in 9 out of 12 subjects when the tonic trend was considered but levels correlated in only 6 out of 12 subjects when the tonic trend was removed and only phasic variations considered. Cardiovascular parameters showed inconsistent correlations to plasma CA in the 8 h subjects although plasma NE correlated positively with mean arterial blood pressure in all 3. These data suggest that resting plasma levels of both CA vary both tonically and phasically and correlate well in only some individuals, particularly when considered on a short-term, phasic basis.

Adolescent↗
PubMed1980

Basal sympatho-adrenal function in quadriplegic man.

Plasma catecholamines (CA) were measured at 15 min intervals over a 4 h time period in 5 supine, chronic, quadriplegic male humans subjects. CA levels fluctuated over time through a wide range, often exhibiting brief bursts of very high CA levels which differed from the slower duration fluctuations seen in normal subjects. Spikes of increased plasma CA often, but not always, correlated with muscle spasms, urination or pain and were often accompanied by appropriate changes in blood pressure and heart rate. When examined over a 4 h period, the subjects' median plasma norepinephrine (NE) levels (305.5 +/- 26.8 pg/ml) were within the normal, age-corrected range while plasma epinephrine (E) levels (210.4 +/- 48.9 pg/ml) were higher than those seen in normal control subjects (89.0 +/- 6.9 pg/ml) tested under similar conditions. Also, plasma NE and E levels in the quadriplegics correlated positively in 3 out of 5 subjects which was similar to the balance in normal subjects. Therefore, resting sympatho-adrenal tone, as indicated by plasma catecholamine levels, in quadriplegics is not decreased, but is either normal or increased. Activation of these systems is probably under the control of local spinal reflexes which appear to be capable of maintaining many of the resting automatic functions of the individual.

Adrenal Glands↗
PubMed1980

Effect of multiple stress procedures on monkey gastroduodenal mucosa.

Early work using the monkey as subject in behavioral experiments found that chronic, perforating duodenal ulcers could develop. In our own experiments, we were unable to reproduce this finding but did observe the regular occurrence of self-limited lesions in areas of the gut susceptible to chronic ulcer formation in man. Of the three lesions we examined histologically, we found that two of them consisted of foci of gastric metaplasia, lesions found in man in association with dyspepsia and ulcer disease. We also noted that these subjects were delivering normal amounts of hydrogen ion to their duodenums, while subjects with gastric lesions had suppressed entry rates into the duodenum. We thus hypothesized that the combination of stress plus normal rate of entry of hydrogen ion into the duodenum had produced the gastric metaplastic changes.

Animals↗
PubMed1980

Gastric emptying and secretion in monkeys during unavoidable shock.

Gastric fluid and acid secretory rates as well as concurrent fractional emptying rates were determined in monkeys subjected to repeated sessions of unavoidable shock. None of these variables changed from control levels during the first session but, by the last session, acid output was significantly reduced.

Animals↗
PubMed1979

Temporal orientation and education. A direct relationship in normal people.

Neurologists usually do not take socioeconomic status into account when evaluating temporal orientation. Our data indicate that this is a mistake: temporal orientation related directly to education, one measure os socioeconomic level, in New Jersey residents. The neurologist should suspect an abnormality in temporal orientation for patients with (1) some college training and (2) no education beyond high school, if they misstate the day of the month by more than one or three days, respectively.

Confusion↗
PubMed1979

Duodenal pathology in rats following cold-restraint stress.

Rats were found to develop duodenal abnormalities as a monotonic function of stress: following a 41-hr fast, 17% had lesions; when cold stress was superimposed during the last 14 hr of the fast, 38% had lesions; when restraint was superimposed upon the last 17 hr of the fast and accompanied exposure to cold, 83% had lesions. Amount of duodenal pathology correlated across experimental groups with amount of gastric pathology seen, but for individual animals, presence of gastric and duodenal pathology did not necessarily co-vary. The existence of gastric and duodenal pathology in stressed rats mirrors that found in stressed humans and thus gives credence to the notion that the rat is a useful animal for study of acute, stress-induced gastro-duodenal disease.

Animals↗
PubMed1979

Stress-induced ventricular arrhythmias.

Restraint stress produced ventricular arrhythmias in seven of seven guinea pigs monitored by a Holter ECG recorder. Couplets and ventricular tachycardia, never seen in unrestrained guinea pigs, were noted in three. The arrhythmias were associated with high heart rates which showed no tendency to decrease during the restraint period.

Animals↗
PubMed1978

Further evidence of a possible association between house dogs and multiple sclerosis.

The present study was undertaken because of the recent report of an association between familial multiple sclerosis (MS) and prior ownership of a small pet. Forty-five patients with sporadic MS were retrospectively compared with 45 closely matched controls and were found to have owned a significantly greater number of indoor dogs prior to the onset of MS. Importantly, the MS patients had also had more exposure to neurologically ill dogs in the five years before the onset of symptoms. These new data further support the hypothesis that house dogs may serve as an animal vector in MS.

Animals↗
PubMed1977

Synchronized ultradian cortisol rhythms in monkeys: persistence during corticotropin infusion.

A highly synchronized ultradian cortisol rhythm with a predominant periodicity of 85 to 90 minutes was observed in eight isolated monkeys; this rhythm may be harmonically related to the circadian rhythm. The persistence of this synchronized rhythm during supramaximal infusions of adrenocorticotropin not only suggests that feedback is not causative but also challenges the classic concept that bursts of cortisol secretion are dependent upon an immediately preceding release of adrenocorticotropin.

Adrenocorticotropic Hormone↗
PubMed1977

Effect of multiple-stress procedures on monkey gastroduodenal mucosa, serum gastrin, and hydrogen ion kinetics.

By arranging a series of psychological contingencies (unpredictability, uncontrollability, conflict), coupled with delivery of a physical stimulus (electric shock), we produced gastroduodenal mucosal lesions in 7 of 8 rhesus monkeys. The most severe conflict paradigm most consistently produced lesions across subjects. Of the 30 lesions observed by endoscopy, 80% occurred near the anatomic junction of gastric body and antrum, in the antrum, or in the duodenum. Lesions varied in severity from discolorations of the mucosa to disruptions of mucosal integrity. Lesions in the stomach generally disappeared in several days despite the continuation of stress; some duodenal lesions were equally evanescent, but in 2 monkeys, lesions lasted over a week. Hydrogen ion kinetics were measured in 2 monkeys that developed gastric lesions and 2 that developed duodenal lesions. The rate at which hydrogen ion entered the duodenum was uniformly suppressed for all 4 monkeys during their first session of shock avoidance; during their last session, the gastric subgroup continued to show suppression while the duodenal subgroup returned towards control levels. Serum gastrin levels were unchanged by the multiple-stress procedures. Our finding of consistently producible, stress-induced gastroduodenal pathology in anatomic areas similar to those involved in man suggests that the subhuman primate is suitable for further efforts to produce an animal model of psychosomatic ulcer disease.

17-Hydroxycorticosteroids↗