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Biomedical subjects

R H Demling

Publications and source records attributed to R H Demling.

180 records · Page 10Linked to original sources
PubMed1975

Effect of acute hemorrhagic shock on pulmonary microvascular fluid filtration and protein permeability in sheep.

In an attempt to further delineate the pathophysiology of the shock-lung syndrome, we studied the effect of hemorrhagic shock on the pulmonary microcirculation in the adult sheep with lung lymph flow and lymph protein transport as indices of fluid filtration and vascular permeability to protein. We noted that lymph flow remained at baseline levels during shock, despite significant decreases in pulmonary artery and left atrial pressures. This suggests that microvascular pressure is maintained by an increase in pulmonary venous resistance. We demonstrated that lymph protein transport does not increase during shock, which indicates that a change in pulmonary vascular permeability to protein does not occur.

Acute Disease↗
PubMedDate not supplied

Oxandrolone, an anabolic steroid, enhances the healing of a cutaneous wound in the rat.

The effect of the anabolic steroid oxandrolone on the healing rate of a standardized full thickness linear wound on the back of the rat was studied. Oxandrolone was given orally by gavage in peanut oil at a dose of 0.1 mg/kg/day. A placebo powder in peanut oil was given at the same dose to a control group. Parameters monitored were time to complete wound closure, wound hydroxyproline content and tensile strength, as well as histology. We found that wounds closed completely in 12+/-3 days with oxandrolone, compared to 18+/-3 days for a placebo, a statistically significant difference. The rate of body weight gain was identical in both groups. Hydroxyproline content of the healed incision site was 23+/-4 mg/g tissue vs. 17+/-3 mg/g tissue, while the tensile strength increased to 185+/-13 g/mm2 vs. 102+/-18 g/mm2 in the oxandrolone and placebo groups, respectively. Both parameters were significantly increased with the anabolic steroid. Histologic examination showed a wound that contained more mature and densely packed collagen and was also hypercellular with oxandrolone treatment. We conclude that the anabolic steroid oxandrolone significantly enhanced wound healing unrelated to any generalized increase in protein mass as would be reflected in body weight.

Anabolic Agents↗
PubMedDate not supplied

The effect of furosemide on the pulmonary transvascular fluid filtration rate.

Considerable controversy exists over the use of furosemide for the prevention of treatment of post traumatic respiratory insufficiency. The conflict revolves around the use of diuretic in a patient with this condition. There is some evidence that a nondiuretic effect of furosemide may be responsible for the reported improvement in lung function. We studied the response to furosemide of the pulmonary microvascular fluid filtration rate reflected in lung lymph flow (Qlym) in the normal lung. Using the unanesthetized sheep lung lymph preparation of Staub, we found a 30% decrease in Qlym after 80 mg furosemide. However, the majority of the decrease occurred within 15 min after injection when diuresis was just beginning. This response appeared to be due to a large decrease in pulmonary venous resistance, decreasing hydrostatic pressure. Protein flow (Qlym x lymph protein content) remained constant. Pulmonary artery pressure remained constant with left atrial pressure decreasing slightly. We have demonstrated that in the normal lung, furosemide significantly decreases the fluid filtration rate by a nondiuretic effect. Further studies of this response should help resolve the controversy over the indications for diuresis and center more attention on the actual mechanism of action of furosemide.

Animals↗
PubMedDate not supplied

Oxygen consumption is increased in the postanesthesia period after burn excision.

We studied the intraoperative and postoperative effects of anesthesia and wound excision on oxygen delivery and oxygen consumption after burn injury. Twenty adult sheep were studied: six had halothane anesthesia alone and 14 had anesthesia and third-degree burns over 15% of the total body surface. Body temperatures were maintained within 1 degree C of baseline value during the operations. The burns on six sheep were totally excised and hide from donor sheep was grafted 3 hours after injury; in eight sheep, excision and grafting were done 5 days after injury. We found that 3 hours of anesthesia in controls decreased oxygen delivery (DO2) by 22% +/- 6% and oxygen consumption (VO2) by 30% +/- 7% from waking baseline values primarily because of a decrease in cardiac output as oxygen (O2) extraction from hemoglobin also decreased. However, no base deficit developed. DO2 and (VO2) transiently increased to 9% +/- 3% above baseline value on the sheeps' return to the waking state. Anesthesia and wound excision, which began 3 hours after the burns were formed, decreased DO2 and VO2 by 25% +/- 4% and 32% +/- 4%, respectively, despite baseline filling pressures. However, a base deficit of -3 +/- 1 mEq/L developed during the two-hour operations, which began with the administration of anesthesia alone. Oxygen consumption increased to 25% +/- 6% above the waking baseline value upon each subject's return to the waking state. In the sheep treated 5 days after burn injury, DO2 decreased by 35% +/- 6% and VO2 decreased by 42% +/- 6% below the value during the waking hypermetabolic state when the sheep were under anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Use of Biobrane in management of scalds.

A scald burn is a superficial to mid second-degree burn with a viable dermis beneath the blisters and a good blood flow. However, the burn may be incapacitating because of pain and fluid and heat loss. Biobrane adheres very well to this depth of burn and mechanically and biochemically closes the wound. We have used Biobrane on scald burns for the last 5 years and have found it to be an excellent method of treating superficial second-degree burns.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Excessive liver oxidant stress causes mortality in response to burn injury combined with endotoxin and is prevented with antioxidants.

We studied the effect of the oral administration of a water-soluble antioxidant solution containing ascorbic acid, glutathione, and a precursor for glutathione synthesis, N-Acetyl-L-cysteine, on liver antioxidant activity, liver cell energetics, and mortality in rats in response to a 20% third-degree burn injury challenged 5 days later with an intraperitoneal injection of 30 mg/kg endotoxin. Rats with burns were fluid-resuscitated with subcutaneous Ringer's lactate solution according to the Parkland formula (4 cc/kg/%burn). Rats challenged with endotoxin 5 days after burn were given an additional 100 ml/kg of subcutaneous Ringer's lactate solution immediately after the injection of endotoxin. A group of rats with burns challenged with endotoxin 5 days after burn were given an oral antioxidant solution beginning after burn injury. Liver cell energetics were measured as tissue energy charge potential (ECP), adenosine triphosphate (ATP) content, and total adenine nucleotides. The levels of endogenous liver glutathione, catalase, vitamin C, and vitamin E were measured to monitor antioxidant status. We found that burn injury alone did not produce any mortality over the 6-day period despite a 35% decrease in liver energy charge potential resulting from a decrease in ATP, a 34% decrease in liver catalase activity, and a 20% decrease in liver vitamin C. It was interesting that glutathione increased and vitamin E remained unchanged. We found that endotoxin injury combined with burn injury produced a 61% mortality rate with a 63% decrease in liver energy charge potential, again resulting from a decrease in ATP, a 74% decrease in liver catalase activity, a 16% decrease in vitamin C, and a 29% decrease in vitamin E. Glutathione was significantly decreased compared with burn alone. We compared the liver antioxidant status of survivors with that of nonsurvivors who were killed when appearing moribund and found that glutathione was decreased by 51% and vitamin C by 73% in nonsurvivors over that in survivors, whereas catalase and vitamin E levels were comparable between the two groups. The oral administration of the antioxidants prevented mortality and the decrease in antioxidant activity and attenuated the decrease in energy charge potential. We conclude that a 20% burn produces a modest decrease in liver energy charge potential and antioxidant defenses without producing mortality. The addition of endotoxin further decreases liver antioxidant defenses, liver energy charge potential, and markedly increases mortality. Antioxidants, given post-burn, restored antioxidant defenses, attenuated the altered cell energetics, and prevented mortality, indicating oxidants to be the cause of mortality. This data also suggests that a critical value of decreases in antioxidant defenses and ATP exists, resulting in mortality.

Acetylcysteine↗
PubMedDate not supplied

Increased protein intake during the recovery phase after severe burns increases body weight gain and muscle function.

We determined the effect of protein intake on weight gain and muscle function in the recovery phase after severe burns. Fifteen patients with deep burns between 30% to 50% of total body surface were studied over a 3 week period-after resolution of the hypermetabolic, catabolic state. All patients were studied in an acute rehabilitation hospital affiliated with the burn center. Nutritional profiles; weight gain; and muscle strength, measured by a physical therapy index (0 to 10)--10 being the greatest progress-were measured. All patients were provided a high-calorie, high-protein diet. Group 1 patients (n=8) also were provided a standard nutrient supplement to maintain caloric intake at 30 to 35 kcal/kg/day and to maintain protein intake at 1.3 to 1.5 g/kg/day. Group 2 patients (n=7) were provided a high-calorie, high-protein diet plus a protein hydrolysate (70 g/day) that provided a protein intake of 1.7 to 2 g/kg/day. Group 1 patients averaged a 1 to 1.5 pound weight gain per week or four pounds during three weeks. Their physical therapy index at three weeks of 4+/-0.5 indicated adequate improvement in strength and endurance. Group 2 patients averaged 2.5 to 3 pounds weight gain per week or 8.5 pounds during three weeks. Their physical therapy index of 7+/-0.7 indicated marked gains in muscle strength. Both measurements were significantly higher than those of Group 1. We conclude that increased protein intake by means of adding a protein hydrolysate increases the rate of restoration of body weight and muscle function.

Adult↗
PubMedDate not supplied

Use of human growth hormone combined with nutritional support in a critical care unit.

The administration of growth factors may potentially accelerate recovery during critical illness by reducing body protein catabolism, enhancing wound healing, and improving skeletal muscle function. The purpose of this phase 1 study was to evaluate the safety and initial efficacy of a recombinant growth factor, human growth hormone (GH), combined with nutritional support in a critical care unit. Following an initial control week, 11 individuals received GH (10 mg/day) daily for 1-6 consecutive weeks. Near constant nutrient intake was provided via parenteral and/or enteral feedings throughout the study period. Vital signs and other clinical parameters, blood values, and nutrient excretion were monitored daily. GH administration was not associated with clinically significant adverse effects. During the first 2 weeks of study, nitrogen excretion decreased from 1356 +/- 157 mmol/day (19.0 +/- 2.2 g/day) during control to 899 +/- 107 mmol/day (12.6 +/- 1.4 g/day) with growth hormone (p less than 0.002) in association with markedly reduced urea generation. Significant reductions in potassium excretion (control 100 +/- 11 mmol/day vs 69 +/- 6 with GH; p less than 0.01) and phosphorus excretion (31 +/- 5 mmol/day vs 18 +/- 3; p less than 0.025) also occurred during GH. The protein-conserving effects of GH were sustained during several weeks of treatment. Growth hormone enhanced the efficiency of administered protein and facilitated nitrogen retention without clinically significant adverse effects in this small patient group. Controlled trials are indicated to determine whether use of this anabolic hormone reduces hospitalization time and improves other clinical outcomes in severely injured patients when combined with appropriate nutritional support.

Adult↗
PubMedDate not supplied

Involuntary weight loss and the nonhealing wound: the role of anabolic agents.

Endocrine responses to trauma result in a net catabolic state and exaggerated hepatic gluconeogenesis, with losses in lean body mass that can compromise wound healing. With proper nutrition, reduction of stress, resistance exercise, and the addition of certain anabolic agents, lean body mass can be restored and wound healing promoted.

Anabolic Agents↗
PubMedDate not supplied

Enteral glutamine administration prevents the decrease in cell energy charge potential produced in ileum after a skin burn in the rat.

A skin burn produces a decrease in cell energy charge potential (ECP), a marker of cell function, in the liver and other organs. The process appears to be oxidant induced because reduced glutathione (GSH) appears to be protective. The gut mucosal barrier is also known to be altered after burns and appears to be improved by glutamine, which is a source of energy and GSH production. Neither the relationship between the gut barrier change and the ECP of the gut barrier nor the mechanism of glutamine protection has been defined. The effect of a 20% total body surface area, full-thickness burn in a rat on ECP and GSH content in the ileum and the liver and the effect of oral glutamine (1 g/kg/d) on any changes were studied. Three groups of rats (14 rats per group) were studied: a control group, a group with burns alone, and a group with burns that were given glutamine. Half of the rats were killed 1 day after the burn, and the other half were killed 6 days after the burn. ECP did not decrease 1 day after the burn, but 6 days after the burn, ECP decreased from a control of 0.53+/-0.06 to 0.41+/-0.01 in the liver and from 0.64+/-0.04 to 0.29+/-0.04 in the ileum. In the ileum, glutamine prevented the decrease of the ECP (which increased to 0.58+/-.03), but in the liver, glutamine did not alter the ECP (which remained at 0.42+/-0.05). The GSH content was unchanged after the burn injury in both organs compared with the value before the burn injury. It can be concluded that a delayed decrease in ECP in the ileum occurs after a burn injury. Orally administered glutamine prevents the decrease in ECP, probably by providing cell energy rather than by increasing gut GSH (antioxidant) activity.

Administration, Oral↗
PubMedDate not supplied

Essential microminerals and their response to burn injury.

Certain microminerals, named because of their minute quantities in the body, are essential components for maintaining homeostasis involving, in particular, metabolism, immune defense, and wound healing. In general, these trace elements are characterized by having multiple roles and by demonstrating deficiency syndromes that are complex and difficult to diagnosis. The response of the microminerals to injury, especially burn injury, is not well defined. The purpose of this article is to describe the known roles of the trace elements and the effect of burn injury on circulating and tissue levels. As will be noted, much less is known regarding the impact of trace elements' changes on the injury process than the role of these elements in the normal state. In addition, the amount of trace elements needed for the stress changes after injury are, for the most part, undefined.

Animals↗