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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mammals and birds adapt to prolonged fasting by mobilizing fat stores and minimizing protein loss. This strategy ends with an increase in protein utilization associated with behavioural changes promoting food foraging. Using the Zucker rat as a model, we have investigated the effect of severe obesity on this pattern of protein loss during long-term fasting. Two interactions between the initial adiposity and protein utilization were found. First, protein conservation was more effective in obese than in lean rats: fatty rats had a three times lower daily nitrogen excretion and proportion of energy expenditure deriving from proteins, and a lower daily protein loss in various muscles. This phase of protein sparing is moreover nine times longer in the fatty rats. Second, obese animals did not show the late increase in nitrogen excretion that occurred in their lean littermates. Total body protein loss during starvation was larger in fatty rats (57% versus 29%) and, accordingly, total protein loss was greater in their muscles. At the end of the experiment, lean and obese rats had lost 98% and 82%, respectively, of their initial lipid reserves, and fatty rats still had an obese body composition. These results support the hypothesis that in severely obese humans and animals a lethal cumulative protein loss is reached long before the exhaustion of fat stores, while the phase of protein conservation is still continuing. In contrast, in lean rats, survival of fasting seems to depend on the availability of lipid fuels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationships between lipid availability and protein utilization during prolonged fasting. 150 87

Apparent body composition changes with weight loss on very-low-calorie diet (VLCD) can depend on the method of fat-free mass estimation. In this report the implications of differences in measurement by direct versus indirect methods are examined. The nitrogen sparing and protein economy associated with ketosis is relevant and results of clinical trials with diets of varying composition are presented. The analytical findings of a multicenter, multimethod long-term VLCD study illustrate protein and metabolic conservation during VLCD. Protein losses, by total body nitrogen, over 10 wk dieting, independent of body mass index, were 4.75% of weight lost, as conservatively expected from obesity tissue reduction with no degradation of total energy expenditure. The implications of utilization of glycogen (water and potassium release) in interpretation of diet success and of body compositional change is evaluated. Evidence is presented that ultimate compositional changes with weight change may be individually specific and that body composition may be predicted from weight considerations alone.
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PMID:Factors influencing body composition during very-low-calorie diets. 161 87

An increased aspartate transaminase in the liver of dietary (post-cafeteria) obese rats was found. It was consistent with the functionality of the malate-aspartate shuttle, that could be responsible for enhancement of metabolic efficiency. The muscle and intestine of obese rats showed a greater capacity for alanine and glutamine synthesis than the controls. Furthermore, enterocyte adaptations in the obese rats indicated higher capabilities for the intake of nitrogen than in the controls. In conclusion, the pattern of amino-acid enzyme activities reflected adaptations to keep from amino nitrogen depletion in dietary obesity which were compatible with an enhancement of the metabolic efficiency.
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PMID:Dietary obesity shows adaptations of amino-acid metabolism on enzyme activities to save amino nitrogen. 168 27

Data from 49 men and 48 women included in the Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study in Perth, Western Australia, were analyzed. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were positively correlated (p less than 0.01) with urine sodium, creatine, taurine, histidine, and 3-methyl histidine but not with calcium, magnesium, or potassium. SBP was related (p less than 0.01) with body mass index (BMI). Urine nitrogen, creatinine, and amino acids correlated (p less than 0.001) with each other and with urine sodium, potassium, calcium, and magnesium. Urine magnesium correlated (p less than 0.001) with urine calcium and potassium; urine calcium was not related significantly to urine sodium or potassium. In backwards multiple regression with data from urine collections, SBP was significantly related only to urine sodium (11.9% of variance explained). If alcohol was included as an independent variable, reducing the number of valid cases because of missing values, both alcohol and urine sodium were significant in regression (19.9% of variance explained). In men, DBP was significantly related to BMI and the ratio of 3-methylhistidine to creatine (23.7% of variance explained). For DBP in women, urine sodium was the only variable needed in regression (58.4% of variance explained). Interpretation must be cautious, because these analyses are based on relatively few cases and on single 24-h urine samples. The data are in keeping with suggestions that obesity, alcohol consumption, a meat diet, and sodium intake are important factors predisposing to elevation of blood pressure.
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PMID:Cardiovascular Diseases and Alimentary Comparison Study: preliminary analysis of data from Western Australia. 170 20

Four diets with graded levels of energy at 24% crude protein were fed to C57BL/6J mice for approximately 3 years to develop pelleted non-purified diets. The nitrogen-corrected metabolizable energy (MEn) of the diets ranged from 2.86 to 3.73 kcal per g of dry matter (DM). Fifteen males and 30 females were assigned to each diet. The mice were housed together for 1 week at 7 week intervals, experiencing 5 matings. After the reproduction stage, they were allowed to complete their life span. Moribund mice after 60 weeks of age were subjected to histopathological examination. The highest energy diet showed the following results in comparison with the lowest energy diet: (1) weaning weight of pups increased by 31.6%; (2) males showed slight obesity even during the reproduction stage, but females did not; (3) both sexes developed remarkable obesity after 50 weeks of age with 41.2% (males) and 49.6% (females) increasing in maximum body weight; (4) although daily feed intake decreased by approximately 18%, the MEn was slightly over consumed; (5) females showed higher incidence of alopecia with age; (6) the survival rate after 50 weeks of age decreased earlier and life span was shortened; (7) histopathological changes associated with aging developed earlier. On the other hand, the early death rate of dams at parturition increased with a decrease in dietary energy. It was concluded that at least 2 types of diets are needed throughout the life span of C57BL/6J mice; a high energy diet with an MEn value of 3.73 kcal/g DM for maximum reproduction and a low energy diet with an MEn value of 2.86 kcal/g DM for the long term stage after reproduction to retard obesity and aging most effectively.
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PMID:Effect of the energy density of non-purified diets on reproduction, obesity, alopecia and aging in mice. 174 67

Plasma amino acids of Zucker obese (fa/fa) and lean (Fa/?) rats fed either a reference nonpurified pellet or a cafeteria diet have been studied from 30 to 60 days after birth. Obese rats showed higher plasma branched chain amino acid levels but similar total amino acids, urea and glucose concentrations. The ingestion of a cafeteria diet induced higher levels in many amino acids, as well as in the composite figure in lean rats, but failed to alter total 2-amino nitrogen concentrations in obese rats, despite high levels in several non-essential amino acids and lower values in essential amino acids; urea levels were much lower in rats fed the cafeteria diet. The results are consistent with an impairment of amino acid nitrogen elimination via urea cycle in cafeteria diet-fed rats. This is independent of the hyperinsulinemia-driven plasma accumulation of several essential amino acids induced by genetic obesity. The effects were, then additive.
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PMID:Plasma amino acids of lean and obese Zucker rats subjected to a cafeteria diet after weaning. 180

The aim of this study was to investigate the validity of bioelectrical-impedance analysis (BIA) in measuring changes in lean body mass (LBM) that occur in the treatment of obesity with very-low-calorie diets (VLCDs). Resistance (R), reactance (Xc), and nitrogen balance (BN) were measured for 28 consecutive days in 16 obese women consuming isocaloric and isonitrogenous ketogenic and nonketogenic liquid VLCDs while housed in a metabolic ward. Changes in LBM were calculated by using eight BIA-predictive equations and from cumulative BN. Changes in LBM calculated by BN were larger in the ketogenic than in the nonketogenic diet (1.5 +/- 0.1 vs 0.6 +/- 0.2 kg/28 d, P less than 0.05). Neither R nor Xc changed significantly during treatment with either diet but each equation showed losses of LBM with time. All the equations overestimated the losses in LBM calculated by BN. BIA does not appear to be a valid method for measuring the small losses in LBM that occur during treatment of obesity with VLCDs.
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PMID:Validity of bioelectrical-impedance analysis in measuring changes in lean body mass during weight reduction. 195 29

Advantages of CAPD in diabetic uremic patients may offer better control of visual and neurological disease. There remain some undesired side effects, i.e: obesity, blood lipid imbalance and loss of appetite due to glucose absorption. In February 1988 four diabetic uremic CAPD patients (2 males and 2 females with an average age of 62.25 +/- 11.32, range 52-76) began treatment substituting one of the usual glucose exchanges with 1% aminoacid solution. Treatment time averaged 52 months (range 9-17). Each month the patients were examined clinically and via blood chemistries. Every 3 months clearances, residual renal function, ocular fundus and motor nerve conductance velocity were measured. Plasma nitrogen increased, while triglycerides, cholesterol and total protein remained unchanged; bicarbonate decreased causing slight acidosis. There were no significant variations of either clearances or ultrafiltration and the quantity of insulin administered decreased. Results confirm that a 1% aminoacid solution can be used as an osmotic agent in peritoneal dialysis to prevent some of the complications such as blood lipid imbalance. The slight acidosis can be corrected by increasing the buffer content of the bag.
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PMID:CAPD in diabetics: use of aminoacids. 198 40

Obese patients have a decreased functional residual capacity and, hence, a reduced oxygen supply during periods of apnea. To determine whether obese patients are at greater risk of developing hypoxemia during induction of anesthesia than patients of normal weight, 24 patients undergoing elective surgical procedures were studied. Group 1 (normal) were within 20% of their ideal body weight. Group 2 (obese) were more than 20% but less than 45.5 kg over ideal body weight. Group 3 (morbidly obese) were more than 45.5 kg over ideal body weight. Patients were preoxygenated for 5 min or until expired nitrogen was less than 5%. After induction of anesthesia and muscle relaxation the patients were allowed to remain apneic until arterial saturation as measured by pulse oximetry reached 90%. The time taken for oxygen saturation to decrease to 90% was 364 +/- 24 s in group 1, 247 +/- 21 s in group 2, and 163 +/- 15 s in group 3; these times are significantly different at P less than 0.05 between groups. Regression analysis of the data demonstrated a significant negative linear correlation (r = -0.83) between time to desaturation and increasing obesity. These results show that obese patients are at an increased risk of developing hypoxemia when apneic.
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PMID:Effect of obesity on safe duration of apnea in anesthetized humans. 198 82

Obesity is a major nutritional disorder that produces many abnormal metabolic responses. The effect of injury-induced stresses acting synergistically with the state of excessive body fat is not well known. Plasma levels of circulating free amino acids reflect the net status of protein breakdown and utilization. Hypoaminoacidemia is a common finding in severe injury and its significance in obese subjects was investigated. We measured in 10 obese (body mass index [BMI] greater than 30) and 10 non-obese (BMI less than 30) traumatized (Injury Severity Score [ISS] 17 to 50) patients, the plasma levels of free amino acids in the early "flow" phase of injury when subjects were receiving maintenance fluids without calories or nitrogen. Postabsorptive control samples were obtained from 10 obese and 10 non-obese volunteers. Obese controls showed an increase in valine, leucine, isoleucine, and glutamic acid levels, and a decrease in glycine, tryptophan, threonine, histidine, taurine, citrulline, and cystine levels compared with lean controls. Hypoaminoacidemia was equally seen in traumatized obese and non-obese patients, and it was mainly due to a 24% decrease in nonessential amino acids. Remarkably, essential amino acid levels were the same in all groups. Arginine and ornithine levels were significantly different in traumatized obese compared with non-obese patients. The hypoglycinemia seen in non-obese trauma patients was absent in obese patients. The changes in levels of sulphur-containing amino acids also suggest that monitoring of these levels should be included in the nutritional management of obese trauma patients.
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PMID:Altered plasma free amino acid levels in obese traumatized man. 201 Oct 79


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