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Biomedical subjects

R Luboshitzky

Publications and source records attributed to R Luboshitzky.

At least 19 recordsLinked to original sources

[Prevalence of diabetes mellitus and glucose intolerance in adult Ethiopian immigrants].

339 adult immigrants from Ethiopia were surveyed 1 year after arrival. They were screened for diabetes mellitus and impaired glucose tolerance by measurement of serum HgbA1C levels. The levels were higher than normal in 35 subjects (10.3%), and were significantly higher in immigrants consuming the Israeli diet, which is richer in proteins and carbohydrates, than in those on the Ethiopian diet. Oral glucose load was abnormal in 7 subjects. 3 had overt diabetes mellitus with absent serum insulin response to glucose load. 4 had glucose intolerance with normal insulin secretion. However, clinical appearance of diabetes was incidental and diabetes ketoacidosis was not detected. The overall prevalence of diabetes mellitus and glucose intolerance in this ethnic group (2.1%) is similar to that in the general population of Israel. Longitudinal studies would indicate the exact prevalence and type of diabetes mellitus among the Ethiopian immigrants.

Diabetes Mellitus

[Calcitonin nasal spray for Paget's disease of the bone].

3 patients with prolonged, diffuse, bone pain due to Paget's disease were treated with intranasal salmon calcitonin, 200-400 U/d for 12 months. Within the first 3 months, in all 3 bone turnover decreased 31-35% (as assessed by serum alkaline phosphatase activity and urinary hydroxyproline/creatinine ratio). After 1 year of nasal calcitonin the reduction in serum alkaline phosphatase was 24%, and in urinary hydroxyproline 10%. In addition, pain and functional impairment markedly improved during the year. It is concluded that daily nasal calcitonin spray is well tolerated and effective initial treatment for Paget's disease of the bone.

Administration, Intranasal

[Transient thyroid dysfunction during chronic viral hepatitis treated with alpha-interferon].

2 patients with chronic viral hepatitis were treated with alpha-interferon and developed thyroid dysfunction. Both patients were previously euthyroid and had thyroids of normal size. 1 developed hypothyroidism (FT4 0.49 micrograms/dl; TSH 26.8 mIU/ml) and the other developed hyperthyroidism (FT4 2.72 micrograms/dl; T3 366 ng/ml; TSH 0.15 mIU/ml) 4 and 6 months, respectively, after commencing interferon. Interferon was discontinued, and thyroid function tests returned to normal within 1 and 2 months, respectively, and have remained normal for over a year. Antimicrosomal antibodies in the hypothyroid patient were positive (1:6400), but became negative after 4 months. No specific therapy for the thyroid disorders was given. These findings suggest that alpha-interferon induced transient thyroid dysfunction in patients who were previously euthyroid and were negative for thyroid autoantibodies.

Adult

Increased nocturnal melatonin secretion in male patients with hypogonadotropic hypogonadism and delayed puberty.

Hypogonadotropic hypogonadism (IGD) and constitutional delayed puberty (DP) share a common pathophysiologic process, i.e. GnRH deficiency. Both conditions are heterogenous and exhibit different grades of GnRH deficiency. To discern whether these disorders of GnRH deficiency are associated with altered melatonin secretion profiles, we compared untreated young males IGD (n = 7) and DP (n = 7) to normal pubertal male controls (n = 6). Serum samples for melatonin, LH, and prolactin concentrations were obtained every 15 min from 1900 h to 0700 h in a controlled light-dark environment with simultaneous sleep recordings. Mean (+/- SD) darktime nocturnal melatonin levels were significantly higher in IGD (259 +/- 73 pmol/L) and DP (217 +/- 29 pmol/L) compared with 182 +/- 69 pmol/L in controls (P < 0.02). So were the mean (+/- SD) peak melatonin levels (410 +/- 117, 327 +/- 97 and 298 +/- 95 pmol/L in IGD, DP, and controls, respectively (P < 0.05). Integrated nocturnal melatonin secretion values (AUC) were also higher in IGD and DP (168 +/- 45 and 134 +/- 28) compared with 119 +/- 45 pmol/min.1 x 10(3) in controls (P < 0.02). The time of melatonin peak and the time of onset of the nocturnal melatonin rise were observed earlier in IGD and DP. Light-time mean (+/- SD) serum melatonin levels were similar in all three groups. No correlations were found between melatonin and LH levels, nor between melatonin and prolactin levels. These data indicate that melatonin secretion is increased in male patients with GnRH deficiency. The lack of correlations between melatonin and LH suggest that circulating sex steroids, rather than LH, modulate melatonin secretion in a reverse fashion.

Activity Cycles

High prevalence of vitamin D deficiency among Ethiopian women immigrants to Israel: exacerbation during pregnancy and lactation.

A population of 125 adult Ethiopian women immigrants to Israel was screened for serum levels of calcium, phosphorus, and alkaline phosphatase. Five women (prevalence of 4%) had hypocalcemia and in one of them osteomalacia was found. In the other 120 subjects normal values were recorded. All five patients had low serum levels of 25 hydroxy (OH) vitamin D3 and high parathyroid hormone (PTH) levels. In four of the five patients, clinical and biochemical manifestations of vitamin D deficiency were detected during pregnancy or lactation. Treatment with vitamin D2 for 4-13 months resulted in clinical improvement and partially corrected the biochemical abnormalities, but low serum vitamin D levels and elevated PTH levels persisted. We conclude that vitamin D deficiency among female Ethiopian immigrants to Israel can be ascribed either to dark skin or low calcium and vitamin D intake, or both. As far as we known this is the first report of vitamin D deficiency among such immigrants. Our study suggests the need to be alert to the possibility of vitamin D deficiency in Ethiopian women who have immigrated to Israel, in particular those who are pregnant or are breast-feeding.

Adult

[Thyroid dysfunction and goiter among immigrants from Ethiopia].

1131 immigrants from Gonder, Ethiopia were surveyed a year after arrival in Israel. The overall prevalence of goiter was 46.1%; the lowest rates (6.7%) were in infants (aged 1-2 years) and the peak prevalence in males was 56.7% (in those aged 12-14 years) and in females, 77.7% (in those aged 35-40). A significant decrease in goiter prevalence was observed after the age of 60 for both men (7.2%) and women (35%). The prevalence of hypothyroidism was 1.1%, 2% in children and 0.2% in adults. That of hyperthyroidism was 1.7%, 0.8% in children and 2.4% in adults. The high prevalence of goiter and hyperthyroidism with low prevalence of hypothyroidism probably resulted from the combined effects of food goitrogens and iodine deficiency in Ethiopia, with the latter playing only a minor role. Neither factor was in effect after arrival in Israel. Genetic and hormonal factors may contribute to the low prevalence of both goiter and hypothyroidism in the adult males. In view of the high prevalence of hyperthyroidism, iodine enrichment is not recommended for Ethiopian immigrants.

Adolescent

Brown adipose tissue metabolism in hypothalamic-obese rats.

Studies were performed to evaluate the metabolic changes of brown adipose tissue (BAT) in rats with hypothalamic obesity (VMNL). In vitro 14C-palmitate oxidation and incorporation into triglycerides were similar in VMNL and control rats. However, protein and fatty acid content and incorporation of 14C-palmitate into phospholipid were significantly less in both hyperphagic and normophagic VMNL rats. In order to assess in vivo BAT lipogenesis, rats were injected with 3H2O. Plasma H2O incorporation into BAT lipids was significantly greater in VMNL rats. Likewise, BAT lipid content was higher in obese rats. In another experiment BAT was incubated with U-14C-glucose to evaluate glucose utilization by BAT. 14C-glucose was oxidized and incorporated into both lipids and glycogen more rapidly by obese than by normal rat BAT. Glycogen content was greater in VMNL rats. Tissues were also incubated with 1-14C-pyruvate and 2-14C pyruvate. Pyruvate incorporation into glyceride glycerol and oxidation of 2-14C pyruvate through the Krebs cycle were similar in both obese and control rats. However, the incorporation of pyruvate into glyceride fatty acids was increased in VMNL rats. The results indicate that both fatty acid and lipid synthesis are increased in BAT of obese rats whereas lactate production is decreased and Krebs cycle activity is normal. Some of these changes appear to be independent of the level of food intake.

Adipose Tissue, Brown

Hypothalamus and brown fat: white and brown adipose tissue lipolysis in weanling rats with dorsomedial hypothalamic lesions.

Weanling male Sprague-Dawley rats received bilateral electrolytic lesions in the dorsomedial hypothalamic nuclei (DMN); sham-operated animals served as controls. The animals were fed lab chow and given tap water ad libitum. Fourteen days after the hypothalamic operation they were weighed and measured to assess ponderal and linear growth gains and Lee Index and were sacrificed on the following day. Body weight, body weight gain over two weeks, nose-tail length and gain in nose-tail length, and food intake were all highly significantly reduced in DMNL rats in comparison with controls. Lee Index and efficiency of food utilization were normal, however. Epididymal fat pads weighed less in both absolute and relative (percentage body weight) terms than in controls. Basal lipolysis was increased and epinephrine-stimulated lipolysis was decreased in DMNL rats, as was the protein content of the epididymal fat pads. Lipid content was normal, however. Interscapular brown adipose tissue (BAT) was significantly lighter in DMNL rats than in controls in absolute terms, but all other parameters measured were normal, as were plasma glucose, glycerol, and free fatty acids. Comparison with results from rats that received ventromedial hypothalamic lesions shortly after weaning indicates a differential effect in most epididymal fat pad parameters but similarities to changes in BAT. These data add to previous demonstrations of normal responses to homeostatic challenges in the growth-retarded, hypophagic-hypodipsic rat with lesions in the dorsomedial hypothalamic nucleus.

Adipose Tissue

Brown adipose tissue metabolism in cold-acclimated weanling rats with hypothalamic obesity.

Certain aspects of intermediary metabolism of white (epididymal) and brown (interscapular) adipose tissue (BAT) were studied in cold-acclimated weanling rats with hypothalamic obesity. Groups of rats with ventromedial hypothalamic lesions (VMNL rats) and controls were maintained for four weeks at 6 degrees C and 22 degrees C, respectively. Sham-operated rats served as controls. Cold-acclimated VMNL rats showed greater percent BAT but normal percent epididymal fat pad weight, hypophagia, reduced body weight and body weight gains, hyperdipsia, hyperinsulinemia, normoglycemia and normal circulating fatty acid levels, higher carcass lipid and lower carcass protein. They also exhibited a higher rate of epididymal fat pad lipolysis than the controls, but the increment during cold adaptation was less in the VMNL rats compared with the 22 degrees C-maintained VMNL animals. In-vitro metabolism was determined in both the basal and the epinephrine-stimulated state. Basal-state 14C-palmitate oxidation, BAT fatty acid and lipid contents were increased in VMNL rats but protein content, incorporation into phospholipid and triglycerides, BAT lipolysis and glycolysis were normal in cold-acclimated VMNL rats. Epinephrine-stimulated BAT showed similar fatty acid content and palmitate oxidation and incorporation into triglycerides in VMNL and control rats. Epinephrine-stimulated BAT showed similar fatty acid content and palmitate oxidation and incorporation into triglycerides in VMNL and control rats, but the epinephrine-stimulated increase in lipolysis only in the cold-acclimated VMNL rats. Whereas at 22 degrees C BAT of VMNL rats showed decreased palmitate oxidation and no change of incorporation into phospholipid and triglyceride, during cold acclimation VMNL rats showed normal BAT metabolism and normal response to epinephrine, except for an increase in lipolysis. The data are in agreement with the observation that hypothalamic-obese mature rats have normal cold survival potential and allow us to extend this fact to the normophagic-obese-weanling rat.

Acclimatization

Lipid and lipoprotein pattern in thyroid dysfunction and the effect of therapy.

Lipid and lipoprotein concentrations were studied in 12 hypothyroid and 11 hyperthyroid female subjects, both before and after therapy, and in 27 age matched female controls. Recognized clinical and laboratory criteria established the diagnosis. Lipoproteins, including the sub-fractions of the high density lipoproteins (HDL), were isolated by preparative ultracentrifugation, and the cholesterol (c) and protein (p) contents of each were determined. Total cholesterol, and in particular HDL-c, were elevated in the hypothyroid patients. The low density lipoprotein (LDL) -c/HDL-c ratio was 1.9 in this group, compared to 2.2 in the control group and 1.35 in the hyperthyroid patients. The HDL-2/HDL-3 ratio in the hypothyroid group was 3.75, as compared to 1.75 in the controls and 4.2 in the hyperthyroid group. Plasma triglycerides were moderately elevated in the hypothyroid patients and were significantly reduced in the hyperthyroid group. Total cholesterol was significantly lower in the hyperthyroid group as compared to the control group. Very low density (VLDL) cholesterol and protein were significantly increased and LDL and HDL cholesterol were reduced in the hyperthyroid patients. On rendering the patients euthyroid, most of these changes were reversed. Thyroid function profoundly affects lipoprotein concentration and composition. The change in the plasma HDL concentrations of the hypothyroid group questions the relationship of this group to arteriosclerosis. Therapy partially corrects the abnormalities, but complete correction may be related to duration of therapy.

Adolescent

Hypothalamic obesity in the weanling rat: dietary self-selection, actual macro-nutrient intake, caloric regulation and response to subsequent low palatability diet.

Weanling male Sprague-Dawley rats received bilateral electrolytic lesions in the ventromedial hypothalamic nuclei (VMNL rats); sham-operated rats served as controls. For 28 post-operative d all animals were fed three equicaloric [16.9 kJ/g (4.03 kcal)] diets with different amounts of macronutrients in each (HCD = high-carbohydrate diet, HFD = high-fat diet and HPD = high-protein diet). VMNL rats selected more than controls from HCD (P less than 0.05) and HFD (P less than 0.01) but similar amounts from the HPD. The total intake from all three diets was greater (P less than 0.001) than that of the controls, but in percent of total diet intakes, VMNL selected proportions comparable to the controls. In terms of macronutient intake, VMNL rats ingested more than controls from each (carbohydrate, P less than 0.001; fat, P less than 0.05; protein, P less than 0.01). Again, in percent of total macronutrient intake, they ingested proportions comparable to the controls. Lee Index (P less than 0.001) was greater and body weight gain/kJ (kcal) smaller (P less than 0.001) in VMNL rats than in controls. However, body weight gains were normal. For the following 14 d, one group of VMNL rats and one control group continued to self-select from the three diets while another VMNL and control group received lab chow [14.2 kJ/g (3.39 kcal)]. Analysis of variance showed a lesion effect for the Lee Index (P less than 0.001) and Lee Index gain /kJ(kcal) (P less than 0.01) but body weight gains and caloric intake were normal among the groups, ie the VMNL rats switched to chow decreased their caloric intake to control levels. On sacrifice, white and brown fat percent protein (P less than 0.001 for both), carcass lipid (P less than 0.001) and protein (P less than 0.01) and plasma insulin (P less than 0.001) showed lesion effects, but there were no differences among the groups in plasma glucose, glycerol, total protein and free-fatty acids. Availability of palatable diets immediately following VMN lesion placement in weanling rats will result in hyperphagia that after one month recedes to normophagia, whether the rats are fed palatable or less palatable diets. Availability of a less palatable diet (chow) following presentation of palatable diets will not result in diminished caloric intake, body weight, obesity and hyperinsulinemia.

Adipose Tissue