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Biomedical subjects

R Luboshitzky

Publications and source records attributed to R Luboshitzky.

At least 73 records · Page 4Linked to original sources
PubMed1981

Metabolic effects of hypothalamic hyperphagia.

In order to test the hypothesis that the enhanced gluconeogenesis of hypothalamic obesity remains responsive to changed in food intake, we have measured gluconeogenesis in two modes of hypothalamic obesity under both hyperphagic and normophagic conditions. The results show that hyperphagia partially decreases gluconeogenesis and fully restores liver glycogen in both modes. The discussion section relates our present findings to the enhanced glucose utilization previously noted after VMH destruction and to the recent hypothesis that hyperphagia is a response to body protein depletion.

Animals↗
PubMed1981

Effects of ventromedial hypothalamic lesions on adipose tissue of weanling male rats.

In weanling male rats, destruction of the ventromedial hypothalamus causes increased carcass lipid deposition and decreased linear growth without changes in food intake or blood glucose levels. These changes are not dependent on altered pituitary function. Lipogenesis and glucose utilization are increased in vivo and in vitro, while gluconeogenesis is accelerated in vivo. The enhanced lipogenesis occurs before increased gluconeogenesis.

Adipose Tissue↗
PubMed1981

High density lipoprotein and arteriosclerosis. Different patterns in primary hypothyroidism and type IIa hyperlipoproteinemia.

Concentrations of high density lipoprotein (HDL) and its subfractions were contrasted in two groups of patients with hypercholesterolemia and a control group of normocholesterolemic subjects. HDL-cholesterol and HDL-protein were low in patients with Type IIa hyperlipoproteinemia, but elevated in patients with primary hypothyroidism. HDL-3 levels were low whereas those of HDL-2 remained unchanged in patients with Type IIa hyperlipoproteinemia. In contrast, in the hypothyroid patients, HDL-3 remained unchanged, while HDL-2 levels were high. The role of HDL in the development of arteriosclerosis in patients with primary hypothyroidism is therefore questioned. Our findings also suggest that measurement of HDL-cholesterol alone cannot be regarded as an accurate indicator of changes in total HDL concentration in different clinical situations.

Arteriosclerosis↗
PubMed1980

Bromocriptine for an acromegalic patient. Improvement in cardiac function and carpal tunnel syndrome.

A 64-year-old woman with active acromegaly of 33 years' duration, severe carpal tunnel syndrome, and subclinical heart disease was treated with bromocriptine mesylate. Within eight months of therapy, basal growth hormone (GH) levels decreased from 90.0 to 7.0 ng/mL, and hand volume was reduced from 375 to 295 mL. Concomitantly, echocardiographic studies showed normal left ventricular size and function. Electromyographic studies demonstrated normal function in both median nerves. Bromocriptine may correct cardiac dysfunction and carpal tunnel syndrome in acromegaly either by reduction of GH oversecretion or by a direct effect of bromocriptine on dopamine receptors in the heart and peripheral nerve endings.

Acromegaly↗
PubMed1980

Bromocriptine-induced pregnancy in an acromegalic patient.

A 30-year-old acromegalic woman with amenorrhea and elevated growth hormone and prolactin levels was treated with bromocriptine. Growth hormone levels remained elevated, while prolactin levels decreased to normal. Forty days after initiating treatment the patient menstruated and conceived shortly afterward. The uneventful pregnancy terminated in delivery of a normal baby, who has been developing normally since. No changes in the size of the sella turcica or the visual field were noted during pregnancy and up to one year after delivery. Resumption of ovulatory menses is possible when treating acromegalic women with bromocriptine. Hyperprolactinemia rather than elevated growth hormone levels or reduced gonadotropins reserve is probably the cause for amenorrhea in some of the acromegalic patients.

Acromegaly↗
PubMed1980

Diminished prolactin reserve in acromegaly.

Prolactin (PRL) secretion has been evaluated in twenty acromegalic patients. All had intact LH, FSH, and cortisol levels and normal thyroid function. Five patients had persistent hyperprolactinemia. The remainder had decreased basal PRL levels with impaired PRL responses to TRH and the dopaminergic antagonist metoclopramide (MET). Despite adequate hypoglycemia and an intact cortisol response, there was no PRL rise following insulin hypoglycemia. The imparied PRL response to TRH was evident in treated and untreated patients and was independent of GH levels. Basal hyperprolactinemia may be related to PRL secretion by the tumor cells or interference with the transport of PIF by the tumor. The decreased PRL reserve noted in the majority of the patients may be related to a decrease in lactotrope cell mass or, alternatively, to enhanced dopaminergic activity.

Acromegaly↗
PubMed1980

Early metabolic changes following destruction of the ventromedial hypothalamic nuclei.

Studies were performed to determine whether increased gluconeogenesis precedes or is necessary for increased lipogenesis after ventromedial hypothalamic destruction. Weanling male rats were injected with 14C-bicarbonate or with 3H2O to assess gluconeogenesis or lipogenesis, respectively, at various short time intervals after placement of hypothalamic lesions. Lipogenesis increased within 2 hr of lesion placement whereas gluconeogenesis did not change for at least 4 hr. The results indicate that lipogenesis increases before gluconeogenesis and, therefore, that enhanced glucose production is not necessary for increased lipogenesis to occur in these rats.

Animals↗
PubMed1980

Hypoxemia and pulmonary function in acromegaly.

Pulmonary function was assessed in 11 patients with acromegaly, 8 of whom were previously treated by external pituitary irradiation. None of the patients had any overt respiratory ailment. Ventilatory function tests were normal in all patients and all had normal total lung capacity ranging from 75 to 123% (mean, 98.18 +/- 4.69%). Eight of ten patients (80%) had hypoxemia with a partial pressure of oxygen in arterial blood ranging between 58 and 90 mmHg (mean, 76.0 +/- 4.2). Calculated alveolar-arterial differences for oxygen ranged between 5.25 and 46.0 (mean, 26.0 +/- 4.7). In 4 of 5 patients in whom lung perfusion scans were performed, perfusion defects were found. There was a significant correlations (p < 0.05) between the presence of hypoxemia and the known duration of acromegaly, but not with the present growth hormone levels or previous therapy. The results indicate that pneumomegaly is not common in acromegaly. However, most patients have some degree of hypoxemia present usually as subclinical disease and it is probably due to a ventilation-perfusion derangement, which is probably a direct effect of the prolonged oversecretion of growth hormone.

Acromegaly↗
PubMed1979

Hyperprolactinaemia and hypogonadism in men: response to exogenous gonadotrophins.

Three male patients with pituitary tumours and marked hyperprolactinaemia were investigated. Their prolactin (PRL) levels ranged from 210 to 2500 ng/ml. The subjects had clinical and laboratory characteristics of hypogonadotrophic hypogonadism. All were treated with human chorionic gonadotrophin (HCG) and in one subject human menopausal gonadotrophin (HMG) was given in addition. In all three patients, despite the persistence of hyperprolactinaemia, serum testosterone had risen to normal levels within 4--17 days after starting HCG. Despite the normal testosterone level, impotence persisted in two patients and the third had persistently decreased libido. The hypogonadism in these patients may be related to an absolute reduction in gonadotroph number secondary to destruction by tumour mass. Alternatively, hyperprolactinaemia may inhibit the synthesis or release of the gonadotrophins or LHRH. Despite hyperprolactinaemia, pharmacological doses of HCG induced testosterone secretion in all these three subjects.

Adult↗
PubMed1978

Chlorthalidone-induced syndrome of inappropriate secretion of antidiuretic hormone.

A 60-year-old woman who had been instructed to increase her water intake because of nephrolithiasis developed the syndrome of inappropriate secretion of antidiuretic hormone when treated with chlorthalidone for mild hypertension. Serum osmolality was 235 mOsm/kg with concomitant urine osmolality of 490 mOsm/kg. When serum sodium decreased to 110 mEq/liter, plasma antidiuretic hormone (ADH) was elevated at 30 pg/ml. The syndrome resolved when chlorthalidone was discontinued together with fluid intake restriction. Plasma ADH returned to normal (less than 0.5 pg/ml) after three days of treatment. The favorable outcome in this patient is attributed to early recognition of the syndrome, which might occur even with nonthiazide diuretics such as chlorthalidone.

Chlorthalidone↗
PubMed1978

Antidiuretic hormone secretion and urine flow in aged catheterized patients.

Repeated measurements of urine flow, every 10 min, and plasma ADH levels, every 20 min, were done in six aged, supine catheterized patients for seven hours. Orthogonal spectral analysis revealed 80 to 130 ultradian rhythms in urinary osmolality and in Na+ and K+ concentrations, but not in the flow of urine that fluctuated rapidly. Plasma ADH levels were constant, ranging from 0.5 pg/ml to 1.5 pg/ml, without evidence for pulsatile episodic secretion.

Aged↗
PubMed1977

Combined calcitonin and oral phosphate treatment for hypercalcemia in multiple myeloma.

Hypercalcemia of multiple myeloma has been discussed widely in the medical literature. The role of calcitonin and phosphate in the treatment of hypercalcemia of multiple myeloma has not yet been studied to our knowledge, although experimental animal models have been pointing to the role of phosphate supplement to calcitonin treatment in multiple myeloma. A patient had multiple myeloma and hypercalcemia. The usual medical treatment for hypercalcemia failed; however, the treatment with combined orally administered phosphate and calcitonin was successful. The role of phosphate depletion in this setting is brought up as an important factor in the failure of calcitonin therapy.

Calcitonin↗
PubMed1975

Mechanis of chlorampenicol-cephalordine synergism on Enerobacteiaeae.

A synergistic in vitro bactericidal effect of combinations of chloramphenicol and beta-lactams on strains of Enterobacteriaceae is described. The synergism is seen with strains which are resistant to the beta-lactam and is due to chloramphenicol-induced inhibition of beta-lactamase production.

Cephaloridine↗
PubMed1973

Bactericidal effect of combinations of nalidixic acid and various antibiotics on Enterobacteriaceae.

The activity of nalidixic acid combined with each of 10 other antimicrobial agents on 95 strains of Enterobacteriaceae was studied. Synergism was found less often than antagonism, and the commonest outcome was indifference. Combinations of nalidixic acid with kanamycin, gentamicin, or colistin were more often synergistic than antagonistic, whereas with the other antibiotics the combination was more often antagonistic than synergistic. Synergistic effects were more common with Shigella than with other genera. In vitro examination for synergism or antagonism appears to be advisable before nalidixic acid is used therapeutically in combination with other antimicrobial agents.

Anti-Bacterial Agents↗