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Query: UMLS:C0235394 (wasting)
 8,040 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The circadian rhythm of the heart rate was assessed using 24 hour electrocardiographic recordings in 18 hospitalized elderly patients with wasting diseases receiving total parenteral nutrition. The nutrient solutions were administered at doses ranging from 360 to 1640 kcal/day. To determine if the heart rate fluctuates rhythmically with a circadian period, the mean hourly heart rate on 24 hour electrocardiographic recordings was used to fit cosine curves by the statistical technique of least squares, and three parameters of the rhythm--designated the mesor, amplitude, and acrophase--were estimated. The cosine curves fitted with a P value of 0.01 or less in all patients before and after insertion of central venous catheters. The mesor represented the rhythm--adjusted mean of the heart rate. The mesor increased significantly with increase in the energy infusion rate (p less than 0.01). The amplitude values were derived from one half of the total diurnal variation of heart rate and the acrophase indicated the time when heart rates were at their peak above the mean. Neither amplitude nor acrophase changed significantly with increase in the energy infusion rate. Furthermore, neither norepinephrine nor epinephrine plasma levels changed with nutrient administration. There were no significant changes in thyroid hormone concentrations. There was a significant positive correlation between mesor changes and rectal temperature with increase in the energy infusion rate (r = 0.76, p less than 0.01). In severely malnourished subjects, changes in the level of feeding can profoundly affect cardiac functions and thermogenic response.
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PMID:[The influence of total parenteral nutrition on the circadian rhythm of the heart rate in elderly patients with wasting diseases]. 251 7

Destruction of the ventromedial hypothalamus produces hyperphagia, hyperinsulinemia and hypertriglyceridemia. These changes appear to be partly the result of increased firing rate of the vagus nerve and reduced firing rate of the sympathetic nerves. These reciprocal changes in the function of the autonomic nervous system appear to provide an adequate explanation for the hyperinsulinemia in this syndrome, and for the reduced heat expenditure. Destruction of the lateral hypothalamus, has effects opposite to those of the ventromedial hypothalamus with a reduction in food intake, a decrease in body fat, and an increase in the activity of the sympathetic nervous system. These reciprocal functions of the hypothalamus are associated with different adrenergic receptors. A medial hypothalamic alpha-adrenergic system mediates the epinephrine stimulation of feeding, and a beta-adrenergic system mediates the lateral hypothalamic inhibition of eating. Peptides from the endorphin family can stimulate food intake, but most other peptides are inhibitory. Growth hormone and thyroid hormone stimulate food intake under appropriate conditions. Insulin and adrenal steroids appear to play the most important role of all the hormones in regulating food intake. Deficiency of adrenal glucocorticoids is associated with decreased food intake and a wasting of body flesh. Increased levels of glucocorticoids, on the other hand, produce a variety of truncal obesity. In animals with ventromedial hypothalamic lesions and obesity, adrenalectomy will reverse the obesity. In genetically obese rats and mice, adrenalectomy will attenuate the progression of the syndrome. These effects appear to be through a reduction of food intake, and an increase in energy expenditure. Injections of insulin will stimulate food intake and may lead to obesity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autonomic and endocrine factors in the regulation of food intake. 286 66

Although patients with thyrotoxicosis improve clinically after treatment with beta-adrenergic blocking drugs, it has never been established whether the hypermetabolism and body protein wasting caused by thyroid hormone excess are actually mediated by adrenergic mechanisms. To evaluate this issue, we measured basal energy expenditure, epinephrine-stimulated calorigenesis, and leucine kinetics (an index of body protein catabolism) in six normal volunteers before and after triiodothyronine (T3) administration (150 micrograms/d for 1 week). Serum T3 rose nearly threefold (P less than 0.001) during T3 administration, producing significant increases in basal metabolic rate (21%, P less than 0.001), nitrogen excretion (45%, P less than 0.001), and leucine flux (45%, P less than 0.01). In response to epinephrine infusion, the absolute rise in metabolic rate above basal was 57% greater in the thyrotoxic condition (P less than 0.02). Although beta-adrenergic blockade with intravenous propranolol totally abolished the calorigenic response to epinephrine, it had no detectable effect on either the accelerated basal metabolic rate or the augmented body protein catabolism caused by thyroid horomone excess. Our data suggest that in the basal, resting state, the increased metabolic rate and accelerated protein breakdown caused by thyroid hormone are not adrenergically mediated. However, under nonbasal conditions (when sympathetic activity is stimulated), enhanced responsiveness to catecholamine calorigenesis may exaggerate the hypermetabolic state and thereby contribute to weight loss and other clinical manifestations of thyrotoxicosis. This mechanism may explain the clinical efficacy of beta-adrenergic blocking agents in the treatment of thyrotoxicosis.
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PMID:Catabolic effects of thyroid hormone excess: the contribution of adrenergic activity to hypermetabolism and protein breakdown. 288 52

The effect of thyroid hormones on mitochondrial respiration are summarized: T3 directly stimulates mitochondrial respiration and the synthesis of adenosine 5'-triphosphate (ATP). Cytosolic ATP availability is increased by a thyroid hormone-induced increase in adenine nucleotide translocation across the mitochondrial membrane; the steady state ATP concentration and the cytosolic ATP/adenosine 5'-diphosphate (ADP) ratio is even decreased in hyperthyroid tissues because of the simultaneous stimulation of the synthesis and consumption of ATP. With regard to the thyroid hormone-induced energy wasting processes, heart work, intra- and interorgan futile cycling and Na+/K+-ATPase are involved to varying degrees. As a consequence of the thyroid hormone-induced hydrolysis of ATP, thermogenesis is increased in hyper- and decreased in hypothyroidism. Despite an increased rate of glucose utilization, clinical and experimental hyperthyroidism is often characterized by an abnormal oral glucose tolerance test. This finding is due to the thyroid hormone-induced increase in intestinal glucose absorption as well as the still enhanced endogenous glucose production in the liver. Hypothyroid patients show a reduced glucose tolerance test because of a decrease in intestinal glucose absorption and a sometimes reduced glucose turnover. The thyroid hormone-induced alterations in glucose metabolism are most probably not due to alterations in serum insulin levels and/or to a peripheral insulin resistance at the receptor level.
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PMID:Thyroid hormone action on intermediary metabolism. Part I: respiration, thermogenesis and carbohydrate metabolism. 632 48

Renal calcium and magnesium handling was studied in rats with chronic thyroid hormone deficiency or excess, hyperthyroidism. Mean kidney weight of the thyroid deficient rats was 42% of age matched, euthyroid and hyperthyroid animals and glomerular filtration rate was 71% of normal. Fractional sodium excretion was consistently elevated in thyroid deficient rats (0.26%) as compared to euthyroid (0.07%) and hyperthyroid animals (0.07%). Urinary calcium excretion (0.39%) was also elevated and parallel to sodium excretion in thyroid deficiency. Despite this renal leak of sodium and calcium, thyroid deficient animals conserved magnesium much more efficiently than either euthyroid or hyperthyroid rats (5.7% vs 17.4% respectively). Plasma magnesium concentration was elevated by acute MgCl2 infusions to determine the reabsorptive capacity of magnesium. Thyroid deficient rats reabsorbed 15-30% more of the filtered magnesium at any given plasma concentration. Although these effects on electrolyte reabsorption are modest compared to the hemodynamic alterations, the data suggest that thyroid hormone has a direct effect on the tubule which if chronically absent results in subtle sodium and calcium wasting and renal retention of magnesium. Administration of thyroid hormone to euthyroid or thyroid deficient rats twenty-four hours prior to experimentation had no effect on calcium and magnesium handling.
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PMID:Effects of thyroid status on renal calcium and magnesium handling. 671 57

Male and female rats were fed standard laboratory chow or a highly palatable diet (cafeteria diet) for 10 wk. The cafeteria diet caused an increase in caloric intake and in body weight, and it induced thermogenesis that was associated with elevated plasma triiodothyronine (T3) levels, increased brown adipose tissue size, and enhanced metabolic response to norepinephrine. For a comparable caloric intake, body-weight gain was significantly greater in female than in male rats possibly because of difference in thermogenesis as suggested by the response to norepinephrine. Exercise training (swimming 2 h/day for 10 wk) reduced food intake and body-weight gain and failed to increase norepinephrine-induced thermogenesis in rats fed laboratory chow. In animals fed the cafeteria diet, food intake and body-weight gain were also reduced by exercise training, which at the same time diminished the diet-induced thermogenesis as evidenced by the diminution of 1) brown fat hypertrophy, 2) the elevation of plasma T3, and 3) the hyperthermic response to injected norepinephrine. It is suggested that the thyroid hormone and catecholamines through their actions on the brown adipose tissue are the important regulatory of thermogenesis. Exercise training would reduce the diet-induced thermogenesis by preventing increased T3 production. Enhanced thermogenesis may be considered an adaptive reaction as it serves to reduce fat deposition in animals fed cafeteria diet and to promote nonshivering heat production in the cold. On the other hand, exercise training reduces thermogenesis and thus prevents energy wasting.
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PMID:Effect of diet and exercise on norepinephrine-induced thermogenesis in male and female rats. 706 71

Cardiopulmonary bypass results in a "euthyroid sick" state. Recently, interest has focused on the relationship between low serum triiodothyronine levels and postoperative cardiovascular hemodynamics. The present study was undertaken to more clearly define the acute effects of triiodothyronine on myocardial mechanics and energetics after hypothermic global ischemia using an ex-vivo canine heart preparation to model the clinical condition. Experiments were performed on isolated hearts subjected to hyperkalemic arrest with 90 minutes of hypothermic (10 degrees C) ischemia. Isolated hearts were cross-perfused by euthyroid support dogs in which triiodothyronine levels spontaneously decreased by 65% to 75% (p < 0.01) after the initiation of cross-perfusion. In nine heart preparations, triiodothyronine (Triostat) was given as a bolus dose (0.2 micrograms/kg) after 1 hour of baseline data collection with a subsequent measurable rise in serum triiodothyronine levels (p < 0.01). In six postischemic hearts, reverse triiodothyronine was given as a 0.2 micrograms/kg bolus. Triiodothyronine was also administered to a group of eight nonischemic, continuously perfused isolated hearts. Intrinsic myocardial contractility was assessed by analysis of the preload recruitable stroke work area, energetic efficiency from the myocardial oxygen consumption-pressure-volume area relationship, and coronary vascular resistance from analysis of coronary flow and perfusion pressure. Acute administration of triiodothyronine to postischemic hearts improved the preload recruitable stroke work area from 9.5 +/- 1.42 to 14.9 +/- 2.03 x 10(7) erg/ml, a 56% increase from baseline (p < 0.001), but had no effect on the preload recruitable stroke work area of the nonischemic hearts. The inotropic response resulting from triiodothyronine treatment did not alter the myocardial oxygen consumption-pressure-volume area relationship. Triiodothyronine treatment was associated with significantly decreased coronary resistance and increased coronary flow through a range of diastolic loading conditions in the postischemic hearts. The biologically inactive thyroid hormone metabolite reverse triiodothyronine was without effect on any of the measured parameters. On the basis of these results, we conclude that the low triiodothyronine state of cardiopulmonary bypass can be reproduced in this isolated heart model and that acute triiodothyronine treatment results in a unique inotropic action manifest only in the postischemic reperfused myocardium and is accomplished without oxygen wasting effects.
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PMID:Triiodothyronine improves left ventricular function without oxygen wasting effects after global hypothermic ischemia. 787 6

Abnormalities of thyroid hormone levels have been reported in the acquired immunodeficiency syndrome (AIDS), but there has been debate as to whether they are appropriate for the clinical status of the patients. Inappropriate maintenance of circulating 3,3',5-triiodothyronine (T3) levels could contribute to weight loss. Although many patients with AIDS have a history of wasting, recent data indicate that prolonged periods of stable weight occur in AIDS and that short-term weight loss is present in a subset of patients with anorexia, many of whom have active secondary infection (AIDS-SI). Therefore we analyzed thyroid hormone levels in a cohort of subjects that have been characterized in terms of recent weight loss and caloric intake. Asymptomatic patients with human immunodeficiency virus infection (HIV+) had short-term stable weights, normal caloric intake, and normal serum T3 levels. In AIDS, average short-term weight was stable, caloric intake was normal, and T3 levels were decreased by 19%. In AIDS-SI, both short-term weight loss and anorexia were significant, and this group showed a 45% decrease in T3 levels. The free T3 (FT3) index was decreased by 30% in AIDS and by 50% in AIDS-SI. Free thyroxine (FT4) levels were decreased while thyroxine-binding globulin (TBG) capacity was increased in HIV+ and AIDS; TBG sialylation was unchanged. Thyrotropin (TSH) levels were slightly increased in AIDS, although levels remained within the normal range. 3,3',5'-triiodothyronine (rT3) levels were decreased in HIV+, AIDS, and AIDS-SI. Thus asymptomatic patients with HIV infection whose weight is stable maintain normal T3 levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Indices of thyroid function and weight loss in human immunodeficiency virus infection and the acquired immunodeficiency syndrome. 841 39

Protracted critical illness is marked by protein wasting resistant to feeding, by accumulation of fat stores, and by suppressed pulsatile release of GH and TSH. We previously showed that the latter can be reactivated by brief infusion of GH-releasing peptide (GHRP-2) and TRH. Here, we studied combined GHRP-2 and TRH infusion for 5 days, which allowed a limited evaluation of the metabolic effectiveness of this novel trophic endocrine strategy. Fourteen patients (mean +/- SD age, 68 +/- 11 yr), critically ill for 40 +/- 28 days, were compared to a matched group of community-living control subjects at baseline and subsequently received 5 days of placebo and 5 days of GHRP-2 plus TRH (1 + 1 microg/kg x h) infusion in random order. At baseline, impaired anabolism, as indicated by biochemical markers (osteocalcin and leptin), was linked to hyposomatotropism [reduced pulsatile GH secretion, as determined by deconvolution analysis, and low GH-dependent insulin-like growth factor and binding protein (IGFBP) levels]. Biochemical markers of accelerated catabolism (increased protein degradation and bone resorption) were related to tertiary hypothyroidism and the serum concentration of IGFBP-1, but not to hyposomatotropism. Metabolic markers were independent of elevated serum cortisol. After 5 days of GHRP-2 plus TRH infusion, osteocalcin concentrations increased 19% vs. -6% with placebo, and leptin had rose 32% vs. -15% with placebo. These anabolic effects were linked to increased IGF-I and GH-dependent IGFBP, which reached near-normal levels from day 2 onward. In addition, protein degradation was reduced, as indicated by a drop in the urea/creatinine ratio, an effect that was related to the correction of tertiary hypothyroidism, with near-normal thyroid hormone levels reached and maintained from day 2 onward. Concomitantly, a spontaneous tendency of IGFBP-1 to rise and of insulin to decrease was reversed. Cortisol concentrations were not detectably altered. In conclusion, 5-day infusion of GHRP-2 plus TRH in protracted critical illness reactivates blunted GH and TSH secretion, with preserved pulsatility, peripheral responsiveness, and feedback inhibition and without affecting serum cortisol, and induces a shift toward anabolic metabolism. This provides the first evidence of the metabolic effectiveness of short term GHRP-2 plus TRH agonism in this particular wasting condition.
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PMID:Reactivation of pituitary hormone release and metabolic improvement by infusion of growth hormone-releasing peptide and thyrotropin-releasing hormone in patients with protracted critical illness. 1019 72

Anorexia nervosa is one of the most common forms of malnutrition observed in Western society in individuals without physical diseases, with an average risk of mortality of 20% in a younger population aged between 15 and 25 years. It is characterised by an initial dramatic decrease in food intake that leads to profound depletion in muscle and fat mass. During the course of the disease, the resting energy expenditure decreases proportionally to the loss of lean body mass with a decrease in thyroid hormone secretion. The metabolic adaptation during anorexia nervosa is similar to that observed during starvation with a relative sparing of protein stores. After an initial weight loss, the total energy expenditure is similar to that in normal individuals, with a decrease in resting energy expenditure and an increased energy-related physical activity. At the end stage of wasting, however, physical activity dramatically decreases as well as energy intake. This metabolic adaptation of semi-starvation is impaired during refeeding with an increase in the thermic effect of food and a high risk of refeeding syndrome with severe hypophosphatemia.
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PMID:From malnutrition to refeeding during anorexia nervosa. 1056 98


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