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Biomedical subjects

R C Baker

Publications and source records attributed to R C Baker.

At least 91 records · Page 5Linked to original sources
PubMed1986

Effects of cage and floor pen management on behavior, production, and physiological stress responses of laying hens.

Behavior, physiology, health, egg production, and egg quality characteristics of laying hens housed either 1/1394-cm2 cage (S), 2/1394-cm2 cage (HD), 2/2788-cm2 cage (LD), or in floor pens (P), each containing 25 hens, were monitored in order to assess hen welfare in different management systems. Egg production was highest in P and S hens. There were no differences among treatment groups in feed efficiency, egg weight, or egg taste, although egg shell breaking strengths were lower in HD hens despite their relatively low egg production. Blood spots were most common in eggs from caged hens. With respect to behavior, penned hens locomoted more, spent less time in stationary exploration than caged birds, and utilized nest boxes for activities in addition to egg laying. The HD hens fed less frequently than did the LD, and HD cage pairs engaged less frequently in simultaneous feeding, drinking, and resting behavior than LD pairs. Plasma corticosterone levels were initially found to be higher in pens than cages; this difference disappeared when the use of trap-nesting to capture P birds for sampling was discontinued. Nighttime corticosterone levels were higher in HD hens. In contrast, primary and secondary hemagglutination titers to sheep erythrocyte (SRBC) antigen, heterophil to lymphocyte ratios, hepatic zinc metallothionein, serum zinc, and body weights did not differ among treatments. Mortality, however, was lower in pens. It was concluded that, although there were striking dissimilarities in behavior between the pen and cage environments, physiological and production data did not provide evidence of stress associated with cage housing per se. High density caging, however, may be a stressor; this is discussed with reference to other research.

Animals↗
PubMed1986

Characteristics of egg yolk phosvitin as an antioxidant for inhibiting metal-catalyzed phospholipid oxidations.

A study was conducted to determine the antioxidant activity of phosvitin in an egg yolk phospholipid emulsion system. Various inorganic and organic metals (Fe2+, Cu2+, and hemin) in several different concentrations were added individually to the emulsions to induce lipid oxidation. Characteristics of phosvitin for inhibiting these metal-catalyzed lipid oxidations were investigated. The effect of heat treatments, both pasteurization (61.1 C, 4 min) and autoclaving (121.1 C, 10 min), on phosvitin was examined to find out if there was any effect on its antioxidant characteristics. Lipid oxidations were measured by thiobarbituric acid assays. Phosvitin effectively inhibited Fe2+ and Cu2+-catalyzed phospholipid oxidations as shown by low malondialdehyde values over the entire reaction period; however, it did not exert similar effects on the hemin-catalyzed oxidation reaction. Phosvitin demonstrated higher capacity to inhibit iron catalysis of phospholipid oxidations (up to 30:1 Fe2+-to-phosvitin molar ratio) than copper catalysis (1:1 molar ratio). Pasteurization did not change the antioxidant activities of phosvitin; however, autoclaving decreased phosvitin's inhibitory capacity on iron catalysis.

Antioxidants↗
PubMed1985

Genetic brain polypeptide variants in inbred mice and in mouse strains with high and low sensitivity to alcohol.

Twelve genetically determined brain polypeptide charge variants were identified by comparing cerebellar vermis of 7 inbred mouse strains and of mice selectively bred from 8 strains closely related to these 7 ancestral strains and one other for acute behavioral sensitivity to the sedative effects of ethanol. The selectively bred ethanol-sensitive (LS, long sleep) and insensitive (SS, short sleep) mice exhibited different allelic variants at 6 of these 12 gene loci expressed in the cerebellum. Variant polypeptide A1 (81 kdalton, pI 5.6) was shown to be associated with the membrane of synaptosomal mitochondria and to exhibit a basic variant in SS mice that is determined by a dominant allele. Other variant polypeptides showed codominant inheritance in F1 crosses. However, the phenotype of no single one of these brain polypeptides consistently correlated with the ethanol behavioral sensitivity of the 7 inbred mouse strains nor of 8 recombinant inbred (B X D, C57BL X DBA) strains. This finding supports the hypothesis that a substantial amount of inbreeding, leading to random fixation of alleles independent of selection for ethanol sensitivity, occurred during the breeding of the SS and LS mice. The present findings of a lack of a strong association between sleep time and a brain polypeptide variant do not preclude the existence of a major gene effect contributing to variation in acute sensitivity to ethanol but are consistent with reports that multiple loci are responsible for the difference in ethanol sensitivity between SS and LS mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Hyponatremia and seizures presenting in the first two years of life.

During a three-month period, 15 patients under two years of age presented with serum sodium concentrations less than 127 mEq/L. Seven (47%) of these patients presented with seizures. Hyponatremia accounted for a majority (58%) of the afebrile seizures in children under two years during this period. Of the eight patients without seizures, four later proved to have cystic fibrosis. Most of the patients with seizures appear to represent the syndrome of infant water intoxication. Hyponatremia may account for more seizures in early life than has been appreciated. Physicians and parents should avoid dietary practices which promote water intoxication. The etiology, diagnosis, and management of water intoxication and hyponatremic seizures are discussed.

Cystic Fibrosis↗
PubMed1985

The frequency of salmonellae on duck eggs.

Total plate counts on washed duck eggs from a breeder farm on Long Island were less than 30/shell during the winter (January to February) of 1982. Clean unwashed eggs had counts less than 9 X 10(1)/shell, whereas dirty unwashed eggs had counts as high as 9 X 10(5)/shell. Our results showed that washing with a chlorine sanitizer (under commercial conditions) was highly effective in reducing surface bacterial counts on egg shells. Prolonged storage reduced bacterial counts on clean eggs, but it did not significantly affect loads on dirty eggs. No salmonellae could be detected on shells or in the magma of all eggs examined. In a second trial (March 1982) bacterial loads on washed and clean duck eggs from six different breeder farms were low, ranging from too few to count to 10(2)/shell. A higher proportion of dirty eggs were heavily contaminated with counts ranging from 10(5) to 10(6)/shell, but no salmonellae were detected either on shells or in magma. In the third trial (May 1982) bacterial determinations on eggs from breeder ducks that were not confined followed the pattern of the second trial. However, in this trial Salmonella enteritidis was detected on dirty egg shells in four of six farms. In a fourth trial (May 1983), bacterial loads on washed and nest-clean eggs from the same breeder farms (not confined) ranged between 10(2) to 10(3)/shell and 10(2) to 10(4)/shell, respectively. S. enteritidis and S. badar were recovered from washed, nest clean, and dirty eggs in two of six farms. We conclude that proper egg washing and confinement of duck breeders should minimize the problem of salmonellosis in ducklings.

Animals↗
PubMed1984

Oxidation of docosahexaenoic acid by rat liver microsomes.

[1-14C]Docosahexaenoic acid (n-3) was incubated at 37 degrees C for 30 min in the presence of rat liver microsomes and 1 mM NADPH. The products were isolated using organic solvent extractions, reverse phase, and normal phase high performance liquid chromatography. Isolates were identified using ultraviolet spectroscopy, capillary gas-liquid chromatography, and gas chromatography-mass spectrometry. The major metabolites were: 19,20-, 16,17-, 13,14-, 10,11-, and 7,8-dihydroxydocosapentaenoic acids, 22-hydroxydocosahexaenoic acid, and 21-hydroxydocosahexaenoic acid. The minor metabolites were 17-hydroxy-4,7,10,13,15,19-, 16-hydroxy-4,7,10,17,19-, 14-hydroxy-4,7,10,12,-16,19-, 13-hydroxy-4,7,10,14,16,19-, 11-hydroxy-4,7,9,13,16,19-, 10-hydroxy-4,7, 11,13,16,19-, 8-hydroxy-4,6,10,13,16,19-, and 7-hydroxy-4,8,10,13,16,19 -docosahexaenoic acids. These metabolites of docosahexaenoic acid resulted from four distinct classes of oxidation, omega-hydroxylations, (omega-1)-hydroxylations, epoxidations, and lipoxygenase-like hydroxylations. The similarity of these product profiles to those reported for comparable microsomal incubations with other essential fatty acids suggest that microsome cytochrome P-450 monooxygenases were involved.

Animals↗
PubMed1983

Survival of Salmonella typhimurium and Staphylococcus aureus in eggs cooked by different methods.

Shell eggs inoculated with Salmonella typhimurium and Staphylococcus aureus were cooked by recommended procedures for boiling, poaching, and frying. Except for poaching, the recommended procedures were inadequate in destroying the inoculum placed in the yolk. Boiling for 7 min was necessary for complete destruction of S. typhimurium and it took 12 min of boiling to destroy Staph. aureus. Cooking time-temperature relationship for complete kill depended on the cooking method with fried eggs. Four minutes and 70 C were needed for covered eggs, 3 min on each side at 64 C for turned over eggs, while cooking for 7.5 min at 64 C for sunnyside eggs was not sufficient for destruction of both of the test organisms. None of the test organisms could be recovered from omelets baked by the recommended procedure (86 C for 25 min). Scrambling for 1 min at 74 C was required for the complete destruction of S. typhimurium and 2 min at 78 C for Staph. aureus.

Eggs↗
PubMed1982

The in vivo metabolism of tertiary butanol by adult rats.

The metabolism of tertiary butanol has been considered to be limited to direct conjugation of the hydroxyl group. Therefore, the alcohol has been used to differentiate between the direct effects of ethanol and those caused by metabolism or metabolic products of ethanol. The in vitro oxidation of tertiary butanol has been reported, and in this report we describe the in vivo oxidation of tertiary butanol. Radiolabeled and stable isotope-labeled acetone was recovered from animals treated with corresponding labeled t-butanol. 14CO2 was also recovered from animals treated with [14C]t-butanol.

Acetone↗
PubMed1981

Controlling heat stress - administrative versus physical control.

The collective effectiveness of several heat stress prevention measures has been evaluated. The relative merits of both physical and administrative controls and their interrelationships have been explored. It is concluded that a combination of physical and administrative control is more effective than any single physical or administrative control in managing heat stress. The use of the preventive measures discussed provided protection to a labor force of 120 employees working approximately 2.4 million man-hours over a six-year period where temperatures average 26.6 degrees C Wet Bulb Globe Temperature (WBGT) during the nonsummer months and 34.4 degrees C WBGT during the summer months. Only three documented cases of heat stress were encountered during this period.

Hot Temperature↗
PubMed1981

A comparison of fresh and frozen poultry.

Chicken broilers, chicken roasters, turkeys, and ducks were split; then one half was stored frozen; the other half was iced. Two days later, both halves were baked and then evaluated using the triangle test. Shear values and expressible fluid values were also determined. The taste panel could not significantly distinguish between fresh and frozen thawed paired halves of roast poultry. Objective testing by shearing and expressible moisture losses also failed to show a significant difference. However, of the judges who could distinguish between the fresh and the frozen thawed samples, the greater percentage preferred the fresh samples.

Animals↗
PubMed1980

Prevalence of salmonellae on eggs from poultry farms in New York State.

The purpose of this study was to determine the prevalence of salmonellae on egg shells. One hundred eggs from each of 14 Central New York poultry farms were tested for salmonella contamination of the shell. The egg magma was examined in those eggs that were positive on shell culture. Only .21% or three of the egg shells yielded salmonellae, all three of which were identified as S. typhimurium. No salmonellae were found in the magma of these eggs. Feed samples from 12 farms were also negative for salmonellae. From this study it would appear that the incidence of salmonellae on eggs from Central New York poultry farms is very low.

Animals↗
PubMed1980

Salmonellae recovery following oral and intravenous inoculation of laying hens.

Eggs have gained a reputation as being a source of salmonellae. Given that some hens are exposed to salmonellae, it is important to determine what the risk might be to human health. White Leghorn hens were inoculated with Salmonella typhimurium, since this organism is often mentioned as being a common isolate from eggs and egg products. The hens were inoculated either orally or intravenously via the basalic vein of the wing. The oral inoculation of S. typhimurium did not result in contamination of the egg shells or contents (yolk and albumen) even though the organisms were eliminated with the feces. Intravenous injection did not lead to fecal shedding of salmonellae nor could the organism be isolated from the shell or the egg contents.

Animals↗
PubMed1977

Evidence for participation of cytochrome b5 in microsomal delta-6 desaturation of fatty acids.

The delta-6 desaturation of linoleic acid to gamma-linolenic acid and oleic acid to 6,9-octadecadienoic acid by rat liver microsomes was investigated. Using a specific antibody prepared against purified rat liver cytochrome b5, we demonstrated that cytochrome b5 participated in delta-6 desaturation of both fatty acids. The reaction products were identified as their methyl ester derivatives by argentation thin-layer chromatography, gas-liquid chromatography, and reductive ozonolysis followed by gas-liquid chromatography.

Animals↗
PubMed1976

Stimulation of the microsomal alkylglycerol monooxygenase by catalase.

Liver cytosol contains a heat-sensitive nondialyzable soluble factor necessary for maximal activity of the alkylglycerol monooxygenase present in rat liver microsomes. In this report, we demonstrate that the stimulatory component in rat liver supernatant is catalase. Catalase functions to protect the enzyme from inactivation by H2O2 in addition to its documented ability to retard the noenzymatic oxidation of the pterin cofactor. The protective effect of catalase on alkylglycerol monooxygenase and on the aromatic amino acid hydroxylase systems indicates that H2O2 sensitivity is a general feature of pterin-dependent hydroxylases.

Animals↗