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Biomedical subjects

B R Switzer

Publications and source records attributed to B R Switzer.

14 recordsLinked to original sources

Immune suppression after acute ethanol ingestion and thermal injury.

Acute alcohol ingestion is commonly associated with burn injury. Both alcohol ingestion and burn injury produce immune suppression, but the combination of these factors on immune function has not been investigated. To study this combined effect, immune function was measured in rats with a 30% burn injury following a single ingestion of 2.4 g/kg of ethanol (EtOH) and compared to that of animals with burn injury only, animals with EtOH only, and animals with neither alcohol nor burn injury. Four days after ethanol and/or burn, animals receiving both ethanol and burn injury had significant suppression of in vivo chemotaxis and lymphocyte responsiveness to lipopolysaccharide (LPS) compared to animals receiving either burn injury alone or EtOH alone (P less than 0.05). There was no difference in responsiveness to concanavalin A (Con A). Serum corticosterone was significantly elevated by burn injury but not EtOH ingestion. EtOH treatment prior to injury caused a further increase in corticosterone level that was significantly associated with a decrease in immune function. These results indicate that a single EtOH exposure prior to burn injury produces greater immune suppression than does burn injury alone. This further decrease in immune function may contribute to increased susceptibility to infection and increased mortality in burn patients with acute EtOH ingestion.

Alcohol Drinking

Pharmacokinetics of ethanol in the guinea pig.

Chronic consumption of ethanol by pregnant and nonpregnant guinea pigs for 8 weeks at doses of 1.2 or 1.6 g/kg body weight twice daily affected pregnancy outcome and changed the pharmacokinetics of ethanol elimination. Ethanol treatment as compared to that of isocaloric sucrose decreased maternal weight, and decreased both the litter size and the number of liveborn offspring. Total litter weight was significantly decreased with the low ethanol dose (12% alcohol-derived energy). During pregnancy, low and high doses produced peak blood ethanol concentrations (BEC) of 89 +/- 8 mg/dl (mean +/- SE) and 125 +/- 6 mg/dl, respectively. At the high dose, peak BEC decreased dramatically (about 30%) in both pregnant and nonpregnant animals from treatment weeks 0 to 4; thereafter peak BEC remained depressed up to 8 weeks of treatment, which occurred with a concomitant increased volume of ethanol distribution. With both doses, rates of ethanol elimination and Michaelis-Menten's Vm values were significantly lower among pregnant as compared with nonpregnant guinea pigs during 8 weeks of treatment. These data suggest that the guinea pigs can be a valuable animal model to study the effects of low ethanol doses on fetal growth, the adaptation of peak BEC with duration of treatment and the lower rate of ethanol elimination in pregnancy.

Animals

Effects of dietary protein and ethanol intake on pregnant beagles fed purified diets.

Maternal weight gain of beagles was approximately 50% lower when ethanol was given twice daily at a dose of 1.8 g/kg body weight with either control protein (17% energy from protein) or low protein (8.5%) diet as compared to isocalorically sucrose-treated animals. Similarly, pup birth weights were about 27% lower from beagles given ethanol with either diet when compared to those from sucrose-treated bitches. Two weeks after beginning ethanol treatment, pregnant bitches fed either diet had higher hematocrit values and lower plasma concentrations of albumin and calcium as compared to sucrose-treated animals. Low dietary protein treatment, rather than ethanol, lowered maternal concentrations of red blood cell folate during pregnancy. As compared to sucrose-treated bitches, ethanol prevented folate levels in red blood cells from returning to the normal range by the 9th wk of pregnancy in animals fed low dietary protein. These data show that ethanol consumption and low dietary protein intake, independently of each other, significantly depress maternal weight gain, pup birth weight and some nutritionally related parameters of the mother.

Animals

Medical evaluation of the special supplemental food program for women, infants, and children.

The special supplemental food program for women, infants, and children administered by the United States Department of Agriculture, was evaluated nationally. Participating infants, children under 4 years old, and pregnant and nursing women were investigated initially, and after receiving food supplements. The supplements were iron-fortified infant formula, iron-fortified infant cereals, and fruit juices for the infants, and milk, cheese, iron-fortified cereals, eggs, and fruit juices for the children and women. Initially, the average birth weight was lower and the infant mortality rate was higher than expected in a well nourished population. There was also evidence of slight growth retardation, a high anemia rate, and a high percentage of participants having saturation of transferrin values less 15%. The program had no effect on the prevalence of unsatisfactory values for saturation of transferrin. There was an increase in weight gain during pregnancy, and increase in birth weight, an acceleration of growth, and a reduction in the anemia rate in all participant categories except women in the first and second trimesters of pregnancy.

Agriculture

Diet-hormone interrelationships in the rat.

Twenty-eight-day old male rats were fed, either ad libitum or in restricted amounts, isoenergetic diets containing 2, 5, 10, 15, 25, or 50% lactalbumin and 5, 11.9, or 21.1% fat for 8 weeks. They were then killed and the plasma levels of triiodothyronine (T3), thyroxine (T4), insulin, glucagon, corticosterone, norepinephrine (NE), and epinephrine (E) were measured. Dietary changes explained most of the variation in the plasma concentrations of T3, T4, insulin, and glucagon but less than 20% of the variation in the plasma concentrations of the adrenal hormones. Dietary protein level was directly related to plasma T4, insulin and corticosterone and inversely related to plasma T3, glucagon, NE, and E. Dietary fat level had its most significant effect on the plasma glucagon concentration to which it was inversely related whereas the most noteworthy effect of a low energy intake was to reduce plasma E and thereby to increase the NE/E ratio. A refeeding study confirmed the effects of dietary protein level on plasma hormone concentrations and showed that the changes in diet-hormone interrelationships in 12-week old male rats have been derived by multiple regression analyses of the data.

Animals

Influence of diet on growth in the rat.

Twenty-eight-day old male Sprague Dawley rats were fed, either ad libitum or in restricted amounts, isoenergetic diets containing 2%, 5%, 10%, 15%, 25%, or 50% lactalbumin protein and 5%, 11.9%, or 21.1% fat for 8 weeks and were then killed. Weekly food consumption and body weight, terminal weight, body water and lipid, and liver weight, DNA, RNA, protein, and lipid were measured. The growth rate increased progressively with each increase in the level of dietary protein up to 25% protein and then declined. Growth was also accelerated by a high fat diet but was retarded by restriction of energy intake. Total body lipid correlated directly with the level of fat in the diet. Multiple regression analysis of the type: Y = beta0 + beta1X1 + beta2X2 + B3X3 + B4X4 where Y = rate of weight gain X1 = dietary protein level, X2 = protein efficiency ratio, X3 = appetite factor, and X4 = energy/protein ratio, showed that the maximum rate of weight gain of 58.8 g/week occurred when the diet contained 23% protein. Growth rate declined when the diet contained a higher protein level.

Animals

Effects od dietary protein, fat and energy on blood hemoglobin and hematocrit in the rat.

Twenty-eight-day old male Sprague-Dawley rats were fed diets containing varying levels of protein, fat and energy for 8 weeks and were killed. Blood hemoglobin and hematocrit measured at the time of killing increased progressively with increases in the level of dietary protein up to 50% protein. The Mean Corpuscular Hemoglobin Concentration (MCHC; hemoglobin concentration in g/100 ml red blood corpuscles) reached a plateau in rats fed diets containing 15% protein or more. Rats consuming low (5%) and high (21.1%) fat diets had lower hemoglobin concentration and hematocrit than rats fed the diets with intermediate fat content (11.9%); the level of dietary fat had no effect on the MCHC. Rats fed restricted amounts of diet had similar hemoglobin concentration to rats fed the same diet ad libitum; however the restricted rats had a lower hematocrit and hence a relative elevation of the MCHC.

Animals