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Biomedical subjects

W Kaye

Publications and source records attributed to W Kaye.

72 records · Page 4Linked to original sources

The effect of lithium on the osmoregulation of arginine vasopressin secretion.

The effect of lithium on the plasma arginine vasopressin (AVP) response to the iv infusion of 5% saline was determined in six patients with primary effective disorder. Lithium did not significantly affect baseline weight, plasma osmolality, sodium, or AVP levels. However, lithium significantly increased the mean rate of change or the sensitivity of the plasma AVP response to the osmotic stimulus (from 0.42 +/- 0.17 to 1.08 to 0.24 pg/ml/mosmol/kg; P less than 0.025, by paired t test). This change was associated with a slight but significant increase in the precision of the response, as reflected in the correlation coefficient, but there was no difference in the calculated intercept or osmotic threshold for AVP secretion. This study indicates that patients on lithium do not, as previously suggested, show partial central diabetes insipidus. Rather, AVP secretion seems to be enhanced. Moreover, the mechanism of this enhancement is a specific increase in the sensitivity of the osmoreceptor rather than a lowering of the osmotic threshold for AVP secretion. The effect of lithium cannot be clearly accounted for by any of the physiological variables known to influence the sensitivity of the system and is probably due to an effect of the drug on the level or activity of neuromodulators which influence the function of hypothalamic osmoreceptors.

Adult↗

Carbamazepine diminishes the sensitivity of the plasma arginine vasopressin response to osmotic stimulation.

Carbamazepine, a drug used to treat manic-depressive illness, has been reported to possess antidiuretic properties, but its effects on arginine vasopressin (AVP) secretion are controversial. Consequently, we examined plasma AVP secretion during hypertonic (5%) saline infusion in seven manic-depressive patients while on placebo and after 3-5 weeks of carbamazepine treatment. We also measured carbamazepine's effects on basal levels of the hormone in cerebrospinal fluid. Carbamazepine significantly reduced the sensitivity of the plasma AVP response to osmotic stimulation without affecting the osmotic threshold for AVP secretion. Moreover, carbamazepine did not affect baseline weight, plasma osmolality, plasma sodium, urine output, plasma AVP, or cerebrospinal fluid AVP. Although the functional significance of these findings remain to be fully determined, the fact that carbamazepine significantly reduced AVP secretion without inducing diuresis supports previous suggestions that carbamazepine enhances renal responsivity to available AVP. In addition, since carbamazepine failed to affect the osmotic threshold, the reported cases of carbamazepine-induced inappropriate AVP secretion and water intoxication must be very uncommon and probably represent idiosyncratic responses.

Arginine Vasopressin↗

Disturbances of sleep and cognitive functioning in patients with dementia.

The relationship of sleep, circadian rhythms, and cognitive impairment in dementia patients is briefly reviewed. All-night sleep EEG data were collected in relatively young and relatively unimpaired patients with presumptive Alzheimer's disease and eight age-matched controls. Delta sleep time and Delta sleep % (Stages 3 and 4)--but not REM sleep measures--were significantly reduced in the patients. Implications of these findings are discussed.

Aged↗

Endorphins in the cerebrospinal fluid of psychiatric patients.

In this paper we have reported the results of studies in psychiatric patient groups using the strategy of measuring opioid activity and beta-endorphin (ir) in CSF. Our findings do not lend support to the notion of excess endorphin activity in schizophrenia, but rather suggest the possibility of a decrease in endogenous opioid activity in some schizophrenic patients. In affectively ill patients our data suggest that there may be a relative change in endogenous opioid system activity across state change in manic-depressive illness. Who also found a relationship between nurses' ratings of anxiety and CSF opioid activity in depressed patients, although it is unknown whether this directly relates to the pathophysiology of this symptom, or is related to stress response. The relationship between CSF opioid activity and HPA axis activity, as reflected by urinary free cortisol excretion, supports the notion of important physiologic relationships between these systems and raises the issue of a role for the endogenous opioid system in the abnormal activation of this system in depression. Finally, the finding of increased CSF opioid activity in anorexia nervosa patients when a minimum weight coupled with data relating endogenous opioids to eating behavior raises interesting questions regarding a possible involvement of the endogenous opioid system involvement in this illness.

Adult↗

Differences in salivary habituation to palatable foods in bulimia nervosa patients and controls.

OBJECTIVE: Bulimia nervosa (BN) patients have been shown to experience anomalous responses to food and food cues. We investigated the response to food over time by presenting repeated food cues and measuring changes in physiological (ie, salivation) and subjective responses. METHOD: Subjects were 18 BN women and 18 matched control women. Two palatable food stimuli, regular or frozen yogurt, that varied in macronutrient composition but had similar sensory characteristics, were presented to subjects repeatedly during a laboratory session. After two baseline salivation measures, subjects were presented with eight trials of one of the two yogurts. On Trial 9 a lemon juice dishabituator was presented, with the yogurt stimulus presented again at Trial 10. RESULTS: We found that control subjects had decreased salivation after repeated food presentations. In comparison, BN subjects failed to show a decrease in salivation. The desire to binge increased over trials for the BN subjects, but remained stable for normals. CONCLUSIONS: These data suggest that salivary habituation may be abnormal in BN patients.

Adolescent↗

Body cell mass in cancer-bearing and anorexic patients.

We used a sensitive whole body counter which measures potassium-40 (40K) to determine total body potassium and to estimate body cell mass (BCM) in 104 previously untreated patients with upper gastrointestinal malignancies, 233 normal volunteers, and 18 patients with anorexia nervosa. BCM was greater in normal males than in females. In both normal males and females, the BCM tended to decrease with age, both as an absolute measure and as a percentage of body weight. Anorexia nervosa patients experienced marked weight loss (30.5%), and had significant depletion of absolute BCM, but exhibited relative sparing of BCM as indicated by a rise in BCM as a percentage of body weight. This may reflect a normal adaptation and predominant fat utilization in chronic malnutrition. The cancer patients, on the other hand, had significant weight loss (12.7% for females, 13.9% for males) and demonstrated a proportional decline in BCM, with no change in BCM as a percentage of body weight. These findings support the contention that, in the cancer-bearing patient, weight loss consists of a significant depletion of both fat and BCM. The challenge to the clinicians caring for cancer patients is repletion of this supremely functional body compartment.

Adult↗

Nasal oxygen sampler.

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Catheterization↗