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Biomedical subjects

H M Shizgal

Publications and source records attributed to H M Shizgal.

At least 19 recordsLinked to original sources

The effect of age on the caloric requirement of malnourished individuals.

The effect of age on the response to total parenteral nutrition (TPN) was evaluated in 325 patients by measuring body composition by multiple-isotope dilution at the onset and at 2-wk intervals during the course of TPN. On the basis of their initial body composition, patients were divided into two groups: normally nourished and malnourished. TPN did not alter the body composition of the normally nourished patients. In the malnourished patients, a statistically significant correlation existed between the daily change in the dependent variable body cell mass (BCM) and the independent variables caloric intake, nutritional state, and age. With advancing age, more calories are required to maintain the BCM of malnourished patients. With a similar nutritional intake, a depleted BCM is restored more slowly in older patients. Age is a significant independent variable affecting the response to nutritional support.

Adolescent

Parenteral and enteral nutrition.

Stress and starvation, especially when complicated by sepsis, will give rise to a rapid erosion of the cellular mass, which significantly affects morbidity and mortality. The best clinical evaluation of the nutritional state is obtained from the medical history and the physical examination. In the patient who cannot eat a balanced diet, specialized nutritional support, in the form of either enteral or parenteral nutrition, is required to prevent malnutrition in the normally nourished, or to correct the nutritional state in the malnourished.

Enteral Nutrition

Myocardial hypertrophy: the distribution of cell growth within the layers of the myocardium.

The spatial distribution of radioactively labeled microspheres was studied in normal and in experimentally hypertrophied hearts of adult pigs. The hearts had been "tagged" with microspheres when the pigs were young. When the adult animal was killed, the spatial distribution of the microspheres was identical in the normal and in the hypertrophied hearts. This demonstrates that hypertrophic growth had occurred evenly throughout all layers of the myocardium.

Animals

Pulsatile perfusion: its effects on blood flow distribution in hypertrophied hearts.

Left ventricular hypertrophy was created in 15 pigs by banding the ascending aorta when they were young. The adult animals were placed on normothermic cardiopulmonary bypass and perfused with either nonpulsatile (two groups of pigs) or pulsatile (one group) flows. As long as the perfusion rate was maintained at 70 ml/kg/min, myocardial blood flow distribution as determined by radioactive microspheres, was identical in the hearts with normal sinus rhythm and those with ventricular fibrillation irrespective of the type of perfusion. At low flow rates, however, subendocardial ischemia developed in all three groups, but was most severe in the fibrillating hearts, and was not reversed by pulsatile perfusion.

Animals

Therapeutic approaches to anergy in surgical patients. Surgery and levamisole.

Skin tests (ST) in 1332 patients are associated with increased morbidity from sepsis. Patients with normal skin tests had a 7% major sepsis rate and 2% mortality rate. Thirty-six per cent of anergic (A) patients and 21% of relatively anergic (RA) patients died; 52% of A patients and 34% of RA patients had sepsis. These data include all patients studied and represent their worst skin test. Two studies were done. The first was a retrospective evaluation of effect of surgery upon 49 anergic patients with biliary tract disease, colon cancer, bowel obstruction, hypovolemia and visceral abscesses. The patients did not receive total parenteral nutrition (TPN). The data show that surgery without TPN can reverse the anergic state and did so in 84% of patients reported. The second study was a prospective, double-blind, randomized trial of the effect of levamisole on skin tests, neutrophil chemotaxis (CTX), sepsis and mortality iin 39 preoperative anergic patients. Major sepsis was significantly increased in placebo group (p less than 0.05). Mortality, minor sepsis, restoration of skin tests and chemotaxis were somewhat better in levamisole patients but not statistically so. These studies show that in addition to TPN, surgery and immunorestorative drugs are viable approaches to the management of selected anergic patients.

Adult

The effect of nitrogen-sparing, intravenously administered fluids on postoperative body composition.

The postoperative protein-sparing effect of intravenously administered amino acids was assessed quantitatively by measuring body composition by multiple isotope dilution. Body composition was determined in two groups of 19 patients each, before and on the fifth day following a major abdominal operation. One group of patients received all of their required fluids and electrolytes as a 5% glucose solution. The second group received an isocaloric infusion of protein as a 5% casein hydrolysate solution. The preoperative body composition of both groups was normal. On the fifth day after operation, the mean body weight had decreased by 2.6 plus or minus 0.6 kg in the glucose group and by 2.0 plus or minus 0.5 kg in the protein group. In the patients receiving glucose, this postoperative weight loss was due to a decrease in both body fat and the lean body mass. The mean body cell mass, which represents the total mass of living, functioning cells, decreased from 23.1 plus or minus 1.5 to 19.9 plus or minus 1.4 kg (P less than 0.001), while the extracellular mass increased from 24.9 plus or minus 0.9 to 27.3 plus or minus 0.9 kg (P less than 0.001). In contrast, in the patients receiving protein, the loss of body weight resulted entirely from a loss of body fat, while the body cell mass and the extracellular mass both remained normal. Therefore protein sparing was achieved by the postoperative infusion of protein.

Abdomen

Protein malnutrition following intestinal bypass for morbid obesity.

Intestinal bypass surgery, performed for weight reduction in the morbidly obese patient, is frequently complicated by the development and hepatic complications. In 44 morbidly obese individuals, 55 inches of proximal jejunum were anastomosed, end to side, to 5 inches of distal ileum. All the patients were followed with body composition measurements, performed by multiple isotope dilution, prior to and at regular time intervals following bypass surgery. In 33 patients a decrease in body fat accounted for the entire postbypass weight loss, while the lean body mass remained normal in both size and composition. In these patients, at 1 year, body weights had decreased by 24.4 +/- 2.1%, while the body cell masses had decreased by 2.1 +/- 7.1%. In the remaining 11 patients, the postbypass weight loss resulted from a loss of both body fat and body cell mass. Their body weights at 1 year had decreased by 27.0 +/- 3.0%, while the body fat and body cell mass. Their body weights at 1 year had decreased by 27.0 +/- 3.0%, while the body cell masses decreased by 22.0 +/- 6.1%. Furthermore, their body compositions were characteristic of protein malnutrition with a contracted body cell mass and an expanded extracellular mass. Six of these 11 patients have required admission to hospital on 10 occasions because of malaise, anorexia, debilitating weakness, hypokalemia, and abnormal liver function. They were treated for 14.5 +/- 1.9 days with an intravenous infusion of amino acids without additional nonprotein calories. The body composition, initially characteristic of malnutrition, became normal. Their symptoms disappeared and hepatic function returned to normal. Subsequently a high-protein diet was required to prevent a recurrence of symptoms and to maintain a normal body composition. The data indicate that protein malnutrition developed in 11 of 44 patients undergoing jejunoileal bypass for weight reduction.

Adult

The role of stress hormones in the catabolic metabolism of shock.

The role of catecholamines in shock metabolism in dogs was studied by comparing the metabolism of shock due to cardiac tamponade, shock with catecholamine depletion from prior reserpine adminstration and metabolism in the normal dog with continuous epinephrine infusion. It was concluded that the high serum concentrations of catecholamines in shock probably cause the increased blood lactate, initial hyperglycemia and, possibly, the poor free fatty acid oxidation seen in shock, but do not cause the increased protein catabolism of shock. With the simultaneous infusion of glucagon, cortisol and epinephrine in physiologic dosages, catabolic metabolism similar to that observed in shock was established in the normal dog. Lactacidemia, hyperglycemia, poor ability to oxidize free fatty acid and massive protein breakdown were observed. The decreased metabolic rate and diminished fatty acid mobilization of shock were not duplicated in those in the normal group and are probably a function of hypoperfusion. The importance of these observations is that impaired use of fat and increased protein breakdown, as seen in shock and trauma, are mediated by hormonal changes. It follows that there may be the opportunity to reverse or modify this catabolism by hormonal manipulation in the surgical patient.

Animals

Symposium on nutritional requirements of the surgical patient. 1. Nutrition and body composition.

Body composition measurements were determined by a multiple isotope dilution technique to assess nutritional status of patients and to determine the efficacy of nutritional support. The body composition of 75 patients with severe malnutrition was characterized by a contracted body cell mass with a relatively expanded extracellular mass. An elective operation of moderate severity resulted in a 14% decrease in the body cell mass while the extracellular mass increased by 10%. The 4% postoperative decrease in body weight did not accurately reflect the change in the body cell mass. The efficacy of total parenteral nutrition (TPN) with lipid as the major caloric source was compared with TPN with hypertonic dextrose. With lipid a daily infusion of 44.2 Cal/kg (185 kJ/kg) was required to maintain the body cell mass while with the solution containing hypertonic dextrose 34.7 Cal/kg (155 kJ/kg) was required--a 27% difference. Total parenteral nutrition with hypertonic dextrose is therefore more efficacious than TPN with lipid as the major caloric source.

Amino Acids

Protein and fat utilization in shock.

A previous study demonstrated that in the dog, shock, regardless of its etiology, resulted in increased oxidative utilization of substrates which form lactate and pyruvate as intermediary metabolites. The study implied a concomitant decrease in free fatty acid oxidation, as the oxidative pathway of the latter does not involve the lactate-pyruvate step. To test this hypothesis, free fatty acid metabolism was investigated by infusing carbon-14 labelled fatty acid in 12 normal dogs, in nine animals in shock due to controlled cardiac tamponade, and in six animals with endotoxin shock. The shock state was characterized by significant (p less than 0.05) decrease both in arterial fatty acid concentration and in free fatty acid turnover. In addition, both the rate of free fatty acid oxidation and the percentage of the total CO2 derived from free fatty acid oxidation were significantly (p less than 0.05) diminished. In contrast, urea production rates were higher in shock, and the calculated maximum contribution of protein oxidation to total CO2 production rose from 23% in the control animals to 50% in the test groups.

Animals

The anatomic and metabolic source of lactate in shock.

The size of the lactate pool in canine shock was measured directly by determining the lactate concentration of various organs. All organs tested, except skeletal muscle, had lactate concentrations similar to those of arterial blood. Skeletal muscles had much higher concentrations of lactate than did arterial blood. When 14C-labeled glucose was infused intravenously, it was concluded from the relative specific activities of glucose and lactate in blood that about one-third of lactic acid originates from blood glucose in shock. Only skeletal muscle had lower lactate specific activity than did blood. This is a possible indication that skeletal muscle is the site of production of lactate. Low glucose specific activity in muscle indicates massive glycogen breakdown, which probably serves as a metabolic precursor of lactate. Lactate production from amino acids produced by proteolysis could also play a role.

Amino Acids