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Biomedical subjects

R R Wolfe

Publications and source records attributed to R R Wolfe.

At least 361 records · Page 20Linked to original sources
PubMed1977

Atypical radiographic findings in neonates with absent pulmonary valve and tetralogy of Fallot.

At birth, three infants had typical to-and-fro murmurs and laboratory features suggesting tetralogy of Fallot with absent pulmonary valve. Initial posteroanterior chest x-ray films were atypical for the condition because of the apparent absence of dilation of the proximal pulmonary arterial tree. Lateral chest x-ray films invariably demonstrated a large hilar mass. Radiographic findings on the posteroanterior chest x-ray film considered pathognomonic for the complex lesion may not evolve until later during the first year of life.

Cardiomegaly↗
PubMed1977

Effect of burn injury on glucose turnover in guinea pigs.

Using our guinea pig model, we found the rate of appearance of glucose was elevated during the three phases following burn injury: the burn shock phase, the hypermetabolic phase and the septic phase. The rate of disappearance of glucose initially was not elevated, resulting in hyperglycemia during burn shock, but eventually, the rate of disappearance of glucose increased to the same extent as the rate of appearance of glucose. During the hypermetabolic and septic phases, the glucose turnover rate was elevated, but the plasma glucose concentration was normal. Glucose turnover was poorly correlated with total body oxygen consumption, suggesting that not all of the increased turnover of glucose was due to increased glucose oxidation.

Animals↗
PubMed1976

Hemodynamic responses to acute hematocrit and blood volume alterations in rats.

Previous investigations of polycythemia in rodents failed to delineate the effects of the increased hematocrits from the effects of possible changes in blood volume. The hemodynamic responses of anesthetized rats to acutely produced increases in hematocrit and blood volume were therefore studied in this experiment. Acute isovolumetric polycythemia decreased O2 transport from a control value of 44.9 to 35.1 ml/min/kg 60 min after the exchange-transfusion. However, the high venous O2 content (over 12 Vol.-%) following the production of isovolumetric polycythemia suggested that there was still sufficient oxygen available to the tissues. Hypervolemia significantly modified the response to acute polycythemia. When hematocrit was maintained at a constant level, acute hypervolemia increased O2 transport (to 54.6 ml/min/kg after 60 min), and when acute hypervolemia and polycythemia were induced simultaneously, O2 transport was transiently increased (to 57.5 ml/min/kg after 15 min) and then returned to a value similar to the control level.

Animals↗
PubMed1976

Cardiovascular and metabolic responses during burn shock in the guinea pig.

The hemodynamic and metabolic responses of fatally burned, nonfatally burned, and unburned control guinea pigs were compared. The burns were induced in temporarily anesthetized animals by immersion to either the xyphoid process (70% fatal) or the midabdomen (100%survival) in boiling water for 3 s. Although cardiac output was reduced in all animals postburn, the survivors (MAG) has higher cardiac outputs at lower arterial pressures than the nonsurvivors (XPN). The postburn lactate levels in the XPN were higher than in the MAG, and the postburn values for pH, oxygen consumption, and core temperature were lower in the XPN. In each group, hyperglycemia was evident for 8 h postburn and terminal plasma glucose concentrations were usually elevated or similar to the prevalue. It was concluded that fatal and nonfatal burn shock were distinguished primarily by differences in tissue perfusion.

Animals↗
PubMed1976

Echocardiography in Marfan's syndrome.

Echocardiographic examinations were performed in 26 patients with clinical evidence of Marfan's syndrome. Twelve patients were demonstrated to have isolated dysfunction of the mitral valvular apparatus of varying severity. Four patients demonstrated involvement of the aortic root as well as mitral valvular abnormalities, and six patients had problems involving the aortic root only. Four patients had no demonstrable cardiac abnormalities. Therapeutic decisions which could previously have been made with confidence only on the basis of cardiac catheterization with angiocardiographic studies were made by ultrasonic evaluation.

Adolescent↗
PubMed1976

Ineffectiveness of heparin treatment in burn shock in the guinea pig.

The cardiovascular and metabolic responses during burn shock were characterized in 10 guinea pigs burned to the xyphoid process for 3 s in boiling water. This produced a burn of approximately 70% of the body surface. Their responses were compared to the values obtained at corresponding times in a group of unburned controls (n=10). The effect of Heparin treatment on burn shock was evaluated in another group (n=8) of guinea pigs burned to the xyphoid process and injected subcutaneously with 50,000 U Heparin/kg immediately after being burned. In the burned, untreated (BUT) animals, cardiac output was reduced more than 50% at 15 mins post-burn, and cardiac output remained depressed for the next 8 h. Mean arterial blood pressure was initially maintained in the BUT animals, but started to fall after 3 h. Heart rate, oxygen consumption and core temperature all decreased progressively in the BUT group. Hemoconcentration was evident in the BUT animals, and there was an elevation in the post-burn glucose and lactate levels, a decrease in pH, and no change in free fatty acids. Heparin treatment did not significantly modify 24-h survival, and the post-burn cardiovascular responses of the Heparin-treated animals were similar to those of the BUT animals. Metabolically, the Heparin-treated animals had a significant elevation in free fatty acids post-burn, but otherwise closely resembled the BUT animals.

Animals↗
PubMed1975

Presentation of atrial septal defect in infancy.

Four patients with atrial septal defects and congestive heart failure in the first year of life had none of the classic auscultatory findings of atrial septal defect. Three of four had murmurs suggestive of innocent pulmonary-artery branch stenosis.

Age Factors↗
PubMed1975

Operant conditioning of heart rate in curarized rats: hemodynamic changes.

Three groups of curarized rats were subjected to operant heart rate conditioning with use of a shock-avoidance procedure while cardiac output, mean arterial pressure, and total peripheral resistance were measured. Heart rate changes in the control group remained constant during the entire 90-min experimental period, while cardiac output decreased significantly. Those rats that were reinforced for increasing their heart rate had a small but statistically significant increase in heart rate, but cardiac output decreased to approximately the same extent as in the control group. The group reinforced for decreasing their heart rate demonstrated a large, significant decrease in heart rate and an even larger drop in cardiac output, which was significantly greater than that of either of the other two groups. Operant conditioning of a single facet of the cardiovascular system resulted in significantly larger changes in other cardiovascular parameters, which may have been partly masked by the physiological effects of d-tubocurarine. Therefore, only when these other measures of cardiovascular function are taken into consideration can interpretation of operant heart rate conditioning become meaningful.

Animals↗
PubMed1975

Blood volume responses of rats adppted to different barometric pressures (38482).

The total blood volume, circulating red cell volume (CRCV), and plasma volume of rats exposed for 30 days to either 480 or 380 mmHg were quite different. At the lower altitude 480 mmHg) total blood volume was similar to that found in sea level controls of a similar weight and age, while CRCV was increased and plasma volume was decreased. However, at the higher altitude CRCV was increased to a much greater extent, with the result that the total blood volume was approximately 44% greater than at 480 mmHg. The differences in response to the two barometric pressures became even more striking when the rats adapted to 380 mmHg were compared with their age- and weight-matched controls. Diet restrictions in the absence of hypoxia resulted in significant decreases in CRCV, plasma volume, and total blood volume. Consequently, when compared to these animals, rats adapted to 380 mmHg had a 100% greater total blood volume due primarily to a higher CRCV, but also to a higher plasma volume.

Adaptation, Physiological↗