Search PubMed⌕ Search

Biomedical subjects

J F Pritchett

Publications and source records attributed to J F Pritchett.

11 recordsLinked to original sources
PubMed1984

Muscle protein synthesis and growth of two strains of chicks vaccinated for Newcastle disease and infectious bronchitis.

Rates of in vitro protein synthesis were monitored during an 8-week period in male broilers and Leghorns. The birds received vaccinations during Weeks 2 and 5 posthatching for Newcastle disease and infectious bronchitis by the administration of a standard dose of the mixed vaccine in the drinking water. Both types of birds exhibited a marked decline in the rate of protein synthesis during each week after vaccination. The decline in ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) levels were not as pronounced as those for protein synthesis, but DNA concentrations did tend to reflect the protein pattern between Weeks 5 and 6. Live weight of both types of birds increased at a steady rate throughout the period, but grams of carcass protein accrued per week followed the protein synthesis rate patterns during the 8-week period. The results suggest that Leghorns are more susceptible than broilers to the stress of vaccination.

Animals↗
PubMed1983

Growth and in vitro protein synthesis in two strains of chicks.

An in vitro method was used to estimate rates of skeletal muscle protein synthesis and degradation in fast (broiler) and slow (White Leghorn) growing birds. Four birds/strain were sacrificed at weekly intervals for 8 wk and biweekly thereafter to wk 14. The extensor digitalis communis, a muscle containing both red and white type fibers and the extensor carpi ulnaris, a white fiber-type muscle, were removed from the right wing and incubated in a Krebs-Ringer solution that contained either 14C-tyrosine for determination of rates of protein synthesis or cycloheximide for determination of rates of protein degradation. The contralateral muscles were removed and muscle weight, length and volume recorded. Proximate analysis was conducted on the carcass and inedible portions of the birds to determine protein, fat and moisture content. Nucleic acid concentrations were measured in the wing muscles. Broilers grew more rapidly than Leghorns, with a twofold difference in body weight by wk 3 and a threefold difference by wk 8. The greater total protein deposition, with more of this protein deposited in the carcass portion than the inedible portion. White muscle had a greater growth rate than the mixed fiber type muscle. Concentrations of RNA and DNA were similar between strains.

Animals↗
PubMed1982

Characterization of [3H] corticosterone binding activity in adrenal incubation media.

Glucocorticoid-binding activity in adrenal incubation media was investigated with regard to characterization of a protein-like ligand. Scatchard analysis of corticosterone binding activity indicated the presence of a single non-interacting protein with a dissociation constant (Kd) of 8.81 X 10(-10) M (0 degrees C), a value which is different from that of plasma and cytoplasmic glucocorticoid binding proteins. In addition, an observed lack of affinity of the protein for dexamethasone distinguishes the protein from Type II cytoplasmic receptor proteins. Thus our data suggest a glucocorticoid-binding protein which is distinct from the two known groups of glucocorticoid-binding proteins, corticosteroid-binding globulin (CBG) and cytoplasmic receptors.

Adrenal Glands↗
PubMed1981

The relationship of thyroxine secretion rate to growth of swine.

The thyroxine secretion rate of five barrows and five gilts (Yorkshire x Landrace) was monitored at 4-week intervals from 10 to 26 weeks of age. Thyroxine secretion rate was determined by injecting 131I-thyroxine (20 MUCi) and monitoring both thyroxine concentration in plasma and the decline of labeled thyroxine in plasma over the next 48 to 60 hours. The thyroxine secretion rate increased from 10 to 14 and 14 to 18 weeks of age but remained unchanged thereafter. The metabolic clearance rate of thyroxine increased significantly through 22 weeks of age 11.83, 2.98, 4.65, 6.32 and 6.90 leter/hr), as did the thyroxine distribution space (2.32, 4.32, 7.10, 90.72 and 10.36 liters. Body size (/.75) was correlated with thyroxine distribution space (r = .49) and thyroxine secretion rate (r = .44).

Animals↗
PubMed1981

The effects of floor temperature, supplemental heat and drying at birth on neonatal swine.

The objective was to determine the effects of floor temperature (20 or 30 C), supplemental heat (heat lamp or light bulb) and drying at birth on piglet survival to day 5. Rectal and infrared skin temperatures were taken on 326 piglets for the first 8 hr postpartum. Blood samples were obtained at birth, day 2 and day 5 and analyzed for thyroxine (T4), triiodothyronine (T3) and cortisol by radioimmunoassay. Weight of each pig was recorded at birth and on days 1, 2, and 5. Survival rates were monitored daily. It was postulated that piglets not dried at birth might have increased heat conservation because of vasoconstriction, which may increase the thermostability and survival of the neonate. Supplemental heat was the only treatment that increased rectal temperature after 3 hr postpartum. Skin temperature at 1/2 and 1 hr was increased by drying, and supplemental heat resulted in elevated skin temperatures from 5 to 8 hr postpartum. Plasma cortisol concentrations were elevated at 2 days of age among pigs not given supplemental heat, but no differences were detected at 5 days of age. Plasma T4 concentrations at 5 days of age were lower among male pigs, pigs on the 30 C floor and pigs given supplemental heat. No significant treatment effects were noted in T3 values at day 5. Pig weights and survival rate at 5 days of age were influenced by the interaction of floor temperature and drying pigs at birth. Pigs dried at birth and kept on the 20 C floor were heavier than those on the 30 C floor, whereas those not dried and kept on the 20 C floor weighed less than those on the 30 C floor. The rate of survival was significantly lower among pigs dried at birth and kept on the 20 C floor than among those not dried and on the 30 C floor (80.9 vs 97.2%), while drying had no effect on survival rate among pigs on the 30 C floor (94.5 vs 93.1%).

Animals↗
PubMed1979

Interaction of aging with in vitro adrenocortical responsiveness to ACTH and cyclic AMP.

In vitro adrenal accumulation of cyclic 3'5'-adenosine monophosphate (cyclic AMP) and release of corticosterone in response to adrenocorticotropic hormone (ACTH), cyclic AMP or theophylline was assessed in 60- and 340-day-old male rats. Adrenal tissue from mature animals secreted significantly smaller quantities of corticosterone in response to ACTH, theophylline or cyclic AMP. Additionally, mature tissue accumulated significantly less cyclic AMP after treatment with ACTH or a combination of ACTH and theophylline. The data suggest an age-related refractoriness of adrenal cortical tissue to ACTH which may in part be related to decreased availability of and/or sensitivity to cyclic AMP.

Adrenal Cortex↗