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Biomedical subjects

G F Sheldon

Publications and source records attributed to G F Sheldon.

At least 55 records · Page 3Linked to original sources

Enteral and parenteral feeding influences mortality after hemoglobin-E. coli peritonitis in normal rats.

Enteral feeding with 25% dextrose-4.25% Freamine II (TPN) improves the survival of malnourished animals to normal levels after hemoglobin-E. coli adjuvant peritonitis, whereas intravenous feeding does not. To determine whether intravenous feeding maintained a high survival rate in previously well-nourished animals, 81 rats received TPN via gastrostomy or intravenous infusion for 12 days. They were then fasted for 24 hours and given a septic challenge. Gastrostomy-fed animals survived the challenge significantly better than intravenously fed animals. Enteral feeding appears to be important in producing a high survival rate after hemoglobin-E. coli adjuvant peritonitis.

Animals↗

A novel method for continuous monitoring of bilirubin production in unstressed rats.

We describe a device for continuous infusion and monitoring of exhaled 14CO as a test of hepatic bilirubin production in rats. A Silastic catheter, implanted into a jugular vein under light ether anesthesia, was protected with a spring shield and a cannula swivel. The animals were kept in a modified Bollman cage. delta-[5-14C]aminolevulinic acid, a heme precursor yielding 14CO upon breakdown of heme to bilirubin, was infused at a constant rate. Exhaled 14CO was oxidized to 14CO2 and collected in ethanolamine. The efficiency of the system averaged 97.8%. In untreated animals 14CO production reached a plateau within 12 h; thereafter, it increased by 2.8% per day. The responsiveness of the system was tested by fasting the animals, which stimulated hepatic bilirubin production. Fasting increased 14CO production by 32.8 +/- 8% (mean +/- SD, P less than 0.005) after 72 h. This was associated with an increase in hepatic heme oxygenase activity (+48%, P less than 0.05) and a decrease in microsomal cytochrome P-450 content (-45%, P less than 0.05). Thus, our approach permits continuous monitoring of hepatic bilirubin production without subjecting the animals to the stress of handling, restraint, or anesthesia. The method can easily be applied to other breath tests involving formation of 14CO2.

Aminolevulinic Acid↗

Adrenalectomy in the guinea pig: operative and perioperative management.

Guinea pigs were anesthetized by epidural injection of xylocaine 20 minutes following the administration of chlorpromazine, cortisone, and hydrocortisone. The right adrenal gland was removed aseptically by careful blunt dissection. Ten milliliters of warm saline containing tobramycin was given subcutaneously at the conclusion of the surgery, and the guinea pig was returned to a recovery cage containing a heating pad. Ten days later, the left adrenal gland was removed using similar procedures.

Adrenalectomy↗

Atrial-caval shunting (ACS) after trauma.

Since 1968 the atrial-caval shunt (ACS), along with inflow occlusion at the porta hepatis, has been used at San Francisco General Hospital in 18 trauma patients to control massive hemorrhage from the inferior vena cava, hepatic veins, or liver. Thirteen patients died from irreversible shock. Five patients survived their initial injuries; one of them died 45 days later from the complications of shock and sepsis. No patients survived who sustained blunt trauma and were admitted in cardiac arrest. Only one of ten patients with BP less than 70 mm Hg after resuscitation survived, whereas four of eight with BP greater than 70 mm Hg survived. ACS was used to control caval injuries in seven patients (one survivor), severe hepatic parenchymal fractures in four patients (two survivors), and combined hepatic and caval injuries in seven patients (two survivors). Survivors had an average of 5.75 associated injuries; nonsurvivors had 3.8. No complications of ACS occurred in the surviving patients.

Heart Atria↗

Effects of enteral and parenteral feeding of malnourished rats on body composition.

Many studies have reported similar weight gains and nitrogen balance in groups of well-nourished animals fed either orally or intravenously, but none have investigated the effects on malnourished animals. After protein depleting for 14 days, rats were refed with a D25-4.25% amino acid solution orally ad lib, by gastrostomy, or intravenously. IV animals gained more weight with greater body fat formation than either enteral group but had lower intestinal mass and nitrogen. Route of administration influenced substrate utilization in malnourished animals fed identical diets. We conclude that weight gain cannot be used as a comparative indicator of nitrogen retention between malnourished animals fed enterally and those fed intravenously.

Animals↗

Acute surgical illness in patients with sickle cell anemia.

Acute abdominal pain frequently accompanies sickle cell crisis. The character of this pain may be difficult to discriminate from acute surgical processes such as acute cholecystitis or appendicitis. Seven patients with sickle cell disease presenting with abdominal pain underwent surgery. Review of the medical records demonstrated a characteristic pattern of presentation consistent from crisis to crisis. When patients with known sickle cell disease present with symptoms of abdominal pain, (1) the character of the symptoms, (2) precipitating events, (3) white blood cell count, (4) bilirubin, and (5) fever should be compared with those characteristics in previous crises. Deviation from previous patterns suggests an illness caused by problems other than sickel cell crisis.

Abdomen, Acute↗

Degloving injuries of the extremities and torso.

Degloving injuries of the extremities and torso occur with relative frequency and are associated with a high morbidity and mortality. The common aim of all surgical approaches is to reestablish skin coverage over the injured area, but therapies differ in both technique and results. This survey evaluates the management and results of 21 patients sustaining degloving injury of at least 2/3 the circumference of the torso or an extremity. Initial surgical techniques which employ application of the skin as a full- or split-thickness graft were contrasted with those in which salvage of the entire flap with its subcutaneous tissue was attempted. The results suggest that immediate use of the degloved skin as a full-or split-thickness skin graft gives the most satisfactory coverage to the denuded areas. Other important features in management include frequent observation and immobilization of the extremity postoperatively, and use of mesh grafts when necessary to cover large areas. Recent emphasis on the blood supply of the skin underscores the importance of its circulation as the determinant of flap survival. Daily observation until the flap becomes fixed is mandatory. Primary reattachment of the full-or split-thickness flap by suture or use of compression dressings without grafting is unsuccessful and should be abandoned as an acceptable approach to this problem.

Abdominal Injuries↗

Autoregulation of erythropoiesis by 2,3 diphosphoglycerate during hyperalimentation.

Protein depletion in rats is associated with hemoconcentration, diminution of red cell mass, and suppression of erythropoiesis. In a rat model, repletion with standard diets or total parenteral nutrition was associated with gain in body weight and regeneration of red cell mass. Hematocrit values did not reflect the degree of red cell mass diminution associated with protein depletion. Intravenous repletion of normal and protein-depleted rats, unlike oral refed cohorts, was associated with elevated 2,3 diphosphoglycerate (DPG) values and a 'relative anemia.' It is postulated that elevated red cell 2,3 DPG lowers the hypoxic stimulus for erythropoietin production by enhancing oxygen unloading to the tissues, thus partially compensating for the anemia associated with total parenteral nutrition.

Anemia↗

Role of parenteral nutrition in patients with short bowel syndrome.

More patients with extensive resection of the small bowel--secondary to regional enteritis, mesenteric infarction, cancer, etc.--are surviving perioperative treatment. To avoid nutrition-caused malabsorption and to maintain body composition, intravenous nutrition is initiated with a silastic atrial catheter in the immediate postoperative period. The patients are trained in "home hyperalimentation" procedures designed to allow normal nutrition to be maintained during the months required for bowel adaptation to occur. Because bowel adaptation to the absorption and transport of foodstuffs is in part dependent on the intraluminal presence of foodstuffs, elemental and regular diets are ingested during the period of intravenous support which may last for years. By using combined oral and intravenous nutrition, approximately 20 per cent of patients with short bowel syndrome eventually can take sufficient oral nutrients to sustain life.

Catheterization↗