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Biomedical subjects

R E Dean

Publications and source records attributed to R E Dean.

67 records · Page 4Linked to original sources
PubMedDate not supplied

Feeling the stress: perceptions of burnout among general surgery program directors.

PURPOSE: To document the types and levels of stress experienced by general surgery program directors as they fulfill their education and administrative responsibilities. METHODS: This study consisted of a 3-part survey that incorporated 2 established instruments to help determine the presence of burnout in program directors. A personal projects analysis was used to help identify the tasks most relevant to the role of program director as well as to evaluate their perceptions of these tasks. The Maslach Burnout Inventory (MBI) was used to measure the degree of burnout among program directors. Demographic data were gathered to develop a picture of the background of the program directors and how they spent their time. RESULTS: A total of 71.8% of program directors responded. Of all tasks, teaching received the highest ratings for importance, enjoyment, and control, as well as the lowest ratings for stress. Emotional exhaustion was the most notable aspect of burnout in program directors on the MBI. Program directors scoring high in burnout were younger, had been in their current position fewer years, and had fewer years overall as a program director. CONCLUSIONS: Burnout is more related to age and experience of program director than to features of the program itself.

Journal Article↗
PubMedDate not supplied

L-selectin blockade and liver function in rats after uncontrolled hemorrhagic shock.

Hemorrhagic shock (HS) and resuscitation can be seen as a global body ischemia-reperfusion (I/R) injury characterized by neutrophil infiltration and organ damage. Liver dysfunction occurs early after HS. Adhesion molecules are needed for the first steps ofneutrophil migration. Thus, the purpose of this study was to investigate the role of L-selectin in the liver after uncontrolled HS and resuscitation. Forty-eight Sprague Dawley rats were subjected to uncontrolled HS and resuscitation. Animals were divided into three groups: sham, uncontrolled HS and resuscitation, and uncontrolled HS and resuscitation with anti-L-selectin treatment. At 6 we evaluated liver injury tests, liver tissue myeloperoxidase (MPO), and liver histology. Survival was followed for 3 days and compared between groups. Statistical analysis included Fisher's exact test and one-way analysis of variance. Survival significantly increased from 30% in the control group to 60% in the treated group (p < .05). Hepatocellular and structural injury as well as neutrophil infiltration was significantly decreased in treated animals (p < .05). Thus, blockade of L-selectin resulted in decreased hepatocellular injury and increased survival in our model of uncontrolled HS. Selectins may be important therapeutic targets for blockade in the treatment of HS.

Animals↗
PubMedDate not supplied

Exogenous and endogenous nitric oxide but not iNOS inhibition improves function and survival of ischemically injured livers.

The role of nitric oxide (NO) in liver ischemia/reperfusion (I/R) injury remains controversial and few works have shed more information regarding the effect of exogenous (EX) and/or endogenous NO (EN) under conditions of I/R of the liver. We investigated the role of exogenous and endogenous NO and inducible nitric oxide synthase (iNOS) inhibition in liver function, neutrophil infiltration, and animal survival after liver I/R. Sprague-Dawley rats were subjected to total hepatic ischemia for 90 min using an extracorporeal porto-systemic shunt. The animals were divided into five groups, including the sham porto-systemic shunt with no ischemia, the control ischemic group, the L-arginine-treated group, the sodium nitroprusside (SNP or NaNP)-treated group, and the L-N6-(1-iminoethyl) lysine hydrochloride (L-NIL) (selective iNOS inhibitor)-treated group. The animal survival was followed for 7 days. Liver injury tests, tissue myeloperoxidase (MPO), and histology were analyzed at 6 h postreperfusion. L-Arginine- and sodium nitroprusside-treated groups demonstrated significant improvement in 7 days survival in comparison to the control (20%) (p < .05). The best overall survival was obtained with SNP (70%), followed by survival in the L-arginine treated group (60%). The iNOS inhibitor group (40%) did not show any statistical significance when compared to the control group (p > .05). Liver injury tests and histology scores in the SNP- and L-arginine-treated groups showed significant improvement when compared to the control group (p < .01 and p < .05, respectively). The iNOS group demonstrated only a slight improvement in these parameters. The liver MPO (as a measurement of neutrophil migration into the liver parenchyma) was significantly decreased only in the SNP and L-arginine groups (p < .05) but not in the iNOS group (p > .5). We conclude that NO exogenous donors and substrates for the endogenous pathway are beneficial for the liver after severe I/R and could be important therapeutic targets to prevent damage following this phenomenon.

Alanine Transaminase↗
PubMedDate not supplied

Assessing energy requirements of patients on respirators.

This report documents a specific situation in which indirect calorimetry produced large overestimations of oxygen consumption and energy expenditure of a patient on a respirator. High positive-end expiratory pressures combined with high fractional concentrations of O2 led to perforation of lung parenchyma with considerable loss of O2, which produced subcutaneous emphysema and recurrent pneumothoraces. Typical calculations for determining energy expenditure from O2 consumption, therefore, could not be employed. Calculations utilizing the volume of CO2 expired, however, were less sensitive and variable during this time period. Resting energy expenditures were calculated from the volume of CO2 expired by using 5.52 kcal/l as the caloric equivalent of CO2. This procedure does not overestimate energy needs when a physiological gas leak exists (high positive-end expiratory pressures and high fractional concentrations of O2 or chest tube). This is very important in the ventilatory patient as excess carbohydrate can further stress the compromised pulmonary status.

Adult↗
PubMedDate not supplied

Effect of enteral feeding bag composition and freezing and thawing upon vitamin stability in an enteral feeding solution.

The effect of enteral feeding bag composition and freezing and thawing upon the stability of riboflavin and vitamins A and E in an enteral feeding solution was tested. Feeding bags composed of either polyvinyl chloride or polyethylene were filled with an enteral feeding solution. The samples were frozen for 3 months, thawed in warm water, and allowed to stand in room temperature for 12 hr. Samples for vitamin analysis were obtained prior to freezing, upon thawing, and at 12 hr after thawing. No significant differences in vitamin stability due to bag composition or time were seen. These results support the viability of the concept of mixing large batches of enteral feeding solution, and freezing aliquots in individual feeding bags for later use.

Drug Stability↗
PubMedDate not supplied

Plasma vitamin and mineral status in home parenteral nutrition patients.

Home parenteral nutrition (HPN) provides long-term nutritional support for persons whose absorptive capacity is compromised by a variety of intestinal malabsorption problems. However, the presence of vitamin and mineral deficiency syndromes that normally would not have time to develop in the hospitalized patient receiving total parenteral nutrition has been reported in patients receiving HPN. This study entails a longitudinal survey of plasma concentrations of vitamins A, E, and 1,25-dihydroxyvitamin D, as well as the minerals zinc, copper, and selenium, in patients receiving HPN. Plasma samples from eight patients who had been on HPN for 1-92 months before the study began were obtained once a month over a 12-month period. The blood was drawn immediately before their evening infusion of TPN in order to approximate fasting plasma nutrient concentrations. Patient values were compared to fasting control values and to published norms. Values for vitamin A, 1,25-dihydroxyvitamin D, and zinc all were within the normal range, and there was no evidence of metabolic bone disease. Plasma vitamin E and copper concentrations exceeded the normal range for most of the 12-month period. Of all of the nutrients studied, only plasma selenium concentrations were consistently in the low-normal to below-normal range. Selenium levels in patients on HPN should be monitored regularly, and supplementation may be necessary if clinical conditions warrant.

Adult↗