PubMed Health⌕ Search

Biomedical subjects

D S Bragg

Publications and source records attributed to D S Bragg.

9 recordsLinked to original sources
PubMed1998

Clinical teaching rounds. A case-oriented faculty development program.

OBJECTIVE: To improve clinical teaching with emphasis on improving provision of feedback through a faculty development series modeled on clinical rounds. METHOD: Seven 1-hour conferences were held for the pediatric faculty during the academic year 1994-1995. Clinical rounds were emulated, with a simulated learner functioning as the patient with a chief complaint of some instructional problem. The conferences progressed from discussion about teaching in a particular situation, to videotapes of clinical teaching, and finally to live clinical teaching. Evaluation of the conferences was assessed by attendance records, participants' evaluations of the conferences, and comparing student and resident evaluations of faculty who attended (i.e., those who attended > or = 2) with faculty who did not attend. Comparisons were made for the academic year before and after the conferences using paired t tests. RESULTS: Forty percent of the faculty attended 2 or more conferences. Mean conference ratings were 4.00 to 4.35, (1 is poor; 5, excellent). Faculty who attended had a significant improvement in ratings for feedback (P = .01) and overall teaching effectiveness (P = .04). Ratings for faculty who did not attend did not change. CONCLUSION: These conferences were well received by the faculty and are an effective way to improve clinical teaching.

Clinical Competence↗
PubMed1989

Uridine monophosphate synthase of Jersey bulls.

Fifteen Jersey sires, with significant impact on the breed in the United States, were assayed for activity of uridine monophosphate (UMP) synthase. Six of these bulls were the highest ranking Jersey bulls, as July 1987, with cheese yield dollars averaging $165. These 15 bulls sired over one-third of all Jersey sons registered in 1986 and 1987 and have registered approximately 14,000 of the 37,000 lactating daughters contributing to active AI sire evaluations in 1988. These bulls represent a cross-section of the Jersey breed as they have 11 different sires; 7 different, additional maternal grandsires; and their five-generation inbreeding coefficients average 1.5%. Activity of UMP synthase was 3.14 plus or minus .24 units/ml with a range from 2.74 to 3.58 units/ml. The coefficient of variation of 7.7% was slightly less than previously reported coefficients of variation for Holsteins. All these Jersey sires had activities within normal expectations, above delimiter of two thirds of average, and none should be considered heterozygous for UMP synthase. Although this is insufficient proof of absence of the undesirable UMP synthase allele among Jerseys, it is reassuring that no heterozygotes were found among these popular Jersey sires.

Animals↗
PubMed1987

Deficiency of uridine monophosphate synthase in Holstein cattle: inheritance and body measurements.

Blood samples and body measurements were obtained from daughters of seven Holstein bulls previously shown to have a partial deficiency of uridine monophosphate (UMP) synthase and presumed to be heterozygous for the condition. Erythrocyte UMP synthase for 85 daughters showed a bimodal distribution with 42 having half the normal activity of 43 others. Furthermore, each bull had 50% of his daughters represented in each group, a finding fully consistent with the heterozygous designation of these bulls. Because UMP synthase is needed for pyrimidine biosynthesis and hence DNA and RNA metabolism, it was hypothesized that a partial deficiency could result in slower growth and smaller size for affected animals. Body measurements, as estimates of growth and size, included body length, wither height, hip height, hip width, rump length, pin width and taped body weight. Although measurements varied by age, differences between normal and heterozygous females were not found. One-half the normal activity of UMP synthase in cattle was adequate for near normal growth. Additionally, herd life was not significantly affected in heterozygous females.

Animals↗
PubMed1987

Incidence and inheritance of deficiency for uridine monophosphate synthase in Holstein bulls.

A partial deficiency of uridine monophosphate synthase has been discovered among Holstein dairy cattle wherein affected animals have half the normal activity of this enzyme and are heterozygous for a condition presumed to be lethal in the homozygous recessive state. A random sample of 287 dairy bulls, active in artificial insemination organizations, were assayed for their activity of uridine monophosphate synthase. Four bulls displayed reduced enzyme activity (heterozygotes) corresponding to a 1.4% incidence and were closely related to a common ancestor, Bull-X. Testing a total of 75 male descendants of Bull-X has uncovered 22 heterozygotes. Heterozygotes include 5 sons, 15 grandsons, 1 a double grandson, and 2 great grandsons of Bull-X. Reproductive failure from this enzyme deficiency has been minimal because matings between close relatives have been infrequent. If the incidence of heterozygotes active in artificial insemination increases, avoidance of matings between close relatives will become an inadequate safety measure to maintain reproductive fitness. Random mating of male heterozygotes to a female population with 2% incidence of heterozygotes may imply an additional .5% embryonic loss relative to matings involving bulls that are normal for uridine monophosphate synthase.

Animals↗
PubMed1986

Influence of age, sex, lactational state and exogenous growth hormone on erythrocyte UMP synthase in dairy cattle.

UMP synthase activity was determined in erythrocytes of Holstein cattle to assess differences attributable to age, sex, lactational state, and exogenous growth hormone. Newborns had 80% more UMP synthase activity per ml erythrocytes than mature cattle. Males had 10% more UMP synthase activity than females of the same age. Lactating and non-lactating mature females did not differ in UMP synthase activity. Over the first six weeks of life, the decrease in UMP synthase activity was less pronounced in calves partially deficient for the enzyme. Ten daily injections of growth hormone altered neither UMP synthase activity in erythrocytes nor orotic acid concentrations in milk and urine.

Aging↗
PubMed1986

Effect of source of carbohydrate and frequency of feeding on rumen parameters in dairy steers.

Four rumen-fistulated, Holstein steers (358 kg) were fed two diets at two frequencies (2 and 8 times/d) in a 4 X 4 Latin square design with 28-d periods. The two diets consisted of corn silage and a concentrate mixture in a ratio of 40:60 on a dry matter basis. The two concentrate mixtures (control and dried whole whey) contained, as a percentage: ground shelled corn, 87.85, 19.05; soybean meal, 9.4, 5.9; dicalcium phosphate, 1.7, 0; trace mineralized salt, 1.0, 1.0; vitamin A and D premix, .05, .05; and dried whole whey, 0, 74.0, respectively. Rumen fluid samples were taken at hourly intervals for 24 h and analyzed for pH, volatile fatty acids, lactate, ammonia nitrogen, and protozoal numbers. Total concentration of volatile fatty acids in the rumen were not affected by treatments. Feeding the control diet resulted in significantly higher ruminal acetate and isovalerate but lower butyrate and valerate expressed as a molar percentage. Increasing the feeding frequency from 2 to 8 times/d resulted in an increase in the molar percentage of acetate and a decrease in the concentration of lactate in ruminal fluid. Numbers of protozoa varied considerably with time after feeding and tended to be higher on the whey diet.

Ammonia↗