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Biomedical subjects

H W Wallace

Publications and source records attributed to H W Wallace.

At least 37 records · Page 2Linked to original sources
PubMed1976

Effect of nitrogen and calorie restriction on protein synthesis in the rat.

The effect of a deficiency of calories and/or nitrogen on protein metabolism in the rat was investigated. During the 5 days of the study, the rats received all nutrients except water via intravenous hyperalimentation. Four diets were used: I) 1.25 g amino acids, 12.5 g glucose/day; II) 1.25 g amino acids/day; III) 1.25 g glucose/day; and IV) 12.5 glucose/day. The rate of protein synthesis in heart, lung, muscle, kidney, and liver was estimated by a modification of the technique of Garlick et al. (The diurnal response of muscles and liver protein synthesis in vivo in meal-fed rats. Biochem. J. 136: 935-945, 1973) except that [15N]glycine was used as the tracer. Heart and lung protein synthesis was depressed by both caloric and nitrogen restriction. Muscle protein synthesis was only significantly affected by omission of calories from the diet. Kidney nitrogen content increased with the amino acid diets and decreased with the nitrogen-deficient diets. The major response of the liver to a dietary deficiency was to lose nitrogen via an increase in the rate of liver protein catabolism.

Animals↗
PubMed1976

Equilibration of 15N-labeled amino compounds in man.

Following an overnight fast, either 15N-labeled glycine, or ammonium chloride, or L-aspartate was orally administered to human volunteers in equal hourly aliquots for 8-12 h. In a parallel series of experiments, [15N]glycine and [15N]ammonium chloride were given intravenously at a constant rate for 10-12 h. The amount of 15N given ranged between 2.7 and 27.3 mg/h. Five hundred milligrams of sodium benzoate were given hourly. Venous blood and urine samples were collected serially. The 15N enrichment of the plasma amino nitrogen, urinary ammonia, hippuric acid, and urea were determined. Irrespective of the 15N carrier used or the route of administration, the plasma amino nitrogen, urinary ammonia, and hippuric acid 15N enrichments approached a plateau within 6-10 h. We concluded that human [15N]glycine metabolism was not atypical of amino acids and that mixing, rather than nitrogen interchange reactions, determines the rate in attaining an approximate plateau.

Amino Acids↗
PubMed1976

The effects of insulin on urinary urea and ammonia production.

15N-labelled glycine, ammonium chloride, and L-aspartic acid were infused intravenously into a series of non-diabetic adults at a constant rate for 4 to 8 hours. Midway during the infusion, a pulse of 8-10 units of regular insulin was injected as a pulse or infused at a constant rate for the remainder of the 15N infusion period. Frequent urine specimens were collected during the infusion period. The 15N enrichment of the urinary urea, ammonia, and amino acids increased smoothly with time until the insulin was given. The pulse of insuline caused a downturn on the N enrichment. We concluded from this that a) the effect of a pulse of insulin on human urea and ammonia metabolism lasted for about one hour; and b) insulin affected glutamine distribution in the plasma.

Amino Acids↗
PubMed1976

Tumor-caused changes in host protein synthesis under different dietary situations.

The effect of the AC33 tumor on protein synthesis in Lewis-Wistar rats was investigated under four different dietary regimens. The four diets used were: (a) 1.25 g amino acids plus 12.5 g glucose per day, (b) 1.25 g amino acids, (c) 1.25 g glucose per day, and (d) 12.5 g glucose per day. The rats were maintained on these four diets for 4 days. On the 5th day, 65 to 75 mg 99.2% [15N] glycine were added to the infusate and infused at a constant rate for the next 18 hr. The rats were then sacrificed and the liver, lung, heart, kidney, anterior tibialis muscle, and tumor were rapidly removed and frozen in liquid nitrogen. The rate of protein synthesis for these tissues was calculated from the ratio of 15N in the tissue protein to that in the tissue intracellular fluid. The protein synthesis rates were compared with the values found for a series of nontumor control rats fed the same diets. Relative to the control rats, muscle protein synthesis decreased on Diet 1, and liver protein synthesis increased with the three deficient diets.

Adenocarcinoma↗
PubMed1976

The contribution of anticoagulants to platelet dysfunction with extracorporeal circulation.

This investigations evaluates the effects of anticoagulants on platelet function. Fresh human blood from 40 nonmedicated volunteers was anticoagulated with 4.3 units per milliliter heparin and/or acid-citrate-dextrose (ACD) solution 1:9. Retention of platelets from whole blood on glass beads was performed by the method of Bowie. Platelet retention of heparinized blood averaged 88.1 +/- S.E. 1.5 per cent; ACD platelets averaged 24.6 +/- S.E. 2.8 per cent. Platelet retention with citrate-phosphate-dextrose (CPD) and ethylenediaminetetraacetic acid (EDTA) yielded 26.0 +/- S.E. 3.9 per cent and 19.1 +/- S.E. 7.5 respectively. The addition of ACD to heparinized blood decreased platelet retention (19.7 +/- S.E. 3.1 per cent). The addition of heparin to ACD or CPD blood did not alter the original decreased retention. Calcium added, even in excess, to blood containing heparin and ACD did not reverse the depressed retention (29.3 +/- S.E. 4.6 per cent). The substitution of CPD gave similar results. With mixtures of separately collected ACD and heparininzed blood, depression of platelet retention was directly proportional to the amount of ACD blood present. Altering the pH of the ACD blood did not affect its depressed retention of platelets. Neutralizing heparinized blood 50 per cent with protamine or Polybrene also significantly depressed platelet retention 34.6 +/- S.E. 5.8 per cent and 35.5 +/- S.E. 4.0 per cent, respectively. Neither protamine nor Polybrene had any effect upon ACD blood. These data indicate that anticoagulants may play a significant role in the depressed platelt function observed during and following extracorporeal circulation.

Anticoagulants↗
PubMed1975

Unusual manifestations of penetrating cardiac injuries.

Penetrating cardiac injuries frequently first appear in an unusual and insidious manner, and their diagnosis may not be immediately obvious. In a series of 20 cases of cardiac injury, ten cases were indicative of such subtle symptoms, several of which were life-threatening. These unusual manifestations can be categorized as early, intermediate, or late. Early problems of four patients included the following: (1) sudden onset of shock during laparotomy, performed due to apparent abdominal trauma; (2) cardiac arrest on arrival in the emergency room; and (3) cerebral air embolus and mimicked symptoms of possible irreversible anoxic brain damage. The intermediate manifestations of cardiac injury are usually discovered in the early recovery period, and include myocardial infarction with cardiogenic shock and bullet embolus to a peripheral artery. Intermediate manifestations were observed in two patients. Four patients had late complications that included pseudoaneurysm, ventricular septal defect, valvular damage, and recurrent pericarditis. These late complications were observed between one month and 21 years after cardiac injury. This indicates the necessity of long-term follow-up of these patients.

Adolescent↗
PubMed1975

Determination of fluorocarbon in blood.

Because fluorocarbons can dissolve relatively large quantities of oxygen and carbon dioxide, there is considerable interest in utilizing them to develop new methods of extracorporael circulation, artificial red blood cells, and liquid breathing techniques. A method for the assay of fluorocarbon in blood is presented. The fluorocarbon is extracted from the blood with toluene, and fluoride is released from the fluorocarbon in the toluene extract by reaction with sodium biphenyl. The inorganic fluoride is then extracted with aqueous sodium acetate, the pH of the extract is adjusted, and the activity of the fluoride ion is read with a fluoride-specific ion electrode. The assay was effective for fluorocarbon concentrations in the range of 1 to 30 ppm.

Biphenyl Compounds↗
PubMed1975

Evaluation of fluorochemicals for liquid membrane oxygenation.

An attempt is being made to develop an oxygenator utilizing gaseous oxygen bubbles completely encapsulated with fluorochemical, thereby avoiding the detrimental changes induced by a blood-gas interface. After the feasibility of this method of oxygenation had been proved, the biocompatibility of the fluorochemicals was investigated. No significant changes in human red blood cells, fibrinogen, or platelets were induced by chronic in vitro contact with fluorochemical over a 24-hour peroid. There is no evidence that the fluorochemicals tested extract lipids from plasma. A device which allowed continuous formation of a blood-fluorochemical interface was utilized in vitro with human blood and in vivo with dogs. No significant alterations were induced by fluorochemicals in the human or animal blood or in the canine organs at autopsy. A prototype oxygenator is now undergoing evaluation. A method of analyzing for fluorochemical in blood and other protein solutions is presented.

Blood Chemical Analysis↗
PubMed1975

Denatured plasma and platelet function.

Thrombocytopenia and platelet dysfunction are well known complications of extracorporeal circulation. The production of ""denatured'' protein is a common occurrence with extracorporeal circulation even in the absence of a blood-gas interface. We subjected platelet-poor plasma to vigorous bubbling with air and studied the effect of this ""denatured'' plasma on platelets from the same donor. Aggregation induced by ADP, epinephrine or collagen was measured. The bubbled plasma decreased the delay in the onset of aggregation observed with collagen and eliminated the biphasic aggregation response induced by epinephrine. These data indicate that ""denatured'' protein may affect platelet function and may play a role in the thrombocytopenia and altered platelet function associated with extracorporeal circulation.

Adenosine Diphosphate↗
PubMed1974

Nonocclusive mesenteric vascular insufficiency.

A case of nonocclusive mesenteric vascular insufficiency in a patient with congestive heart failure on digitalis and with arrhythmia is presented. The preoperative diagnosis was made through mesenteric arteriography. A course of treatment was followed which we believe prevented intestinal gangrene. This regimen includes measures to increase cardiac output, local pharmacologic agents to induce mesenteric vasodilatation, antibiotics, and oxygen. The viability of the intra-abdominal organs was demonstrated by laparotomy.

Angiography↗