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Biomedical subjects

L D Young

Publications and source records attributed to L D Young.

At least 73 records · Page 4Linked to original sources
PubMed1986

Heritability of plasma cholesterol and triglyceride concentrations in swine.

Three-hundred and eighteen female swine representing contemporary commercial swine breeds (34 Chester White, 43 Large White, 42 Landrace, 40 Yorkshire, and 159 four-breed crossbreeds) were used to evaluate genetic variation between and within breeds for levels of plasma cholesterol and plasma triglycerides. Blood was sampled from all pigs after a 16-hr fast at 154 days of age. Plasma cholesterol was measured in all pigs and triglycerides were measured in 232 pigs. Paternal half-sib heritabilities (h2) for plasma cholesterol and plasma triglycerides were 0.45 +/- 0.23 and 1.04 +/- 0.32, respectively. Breed differences were not apparent for either trait. Phenotypic and paternal half-sib genetic correlations between the two traits were 0.16 and 0.66, respectively. Neither body weight nor backfat depth were important in affecting the estimate of h2 for either trait. The relatively high h2 of total plasma cholesterol and of total triglycerides offers the possibility of developing, through selection, populations of hypercholesterolemic or hypertriglyceridemic swine useful as models for studies directed toward further understanding of human cardiovascular disease.

Animals↗
PubMed1986

Effects of oral calcium carbonate on blood pressure in subjects with mildly elevated arterial pressure.

Recent investigations suggest that calcium supplementation may cause a lower arterial pressure in hypertensive individuals. We studied 32 patients with mildly elevated arterial pressure (diastolic pressure 88-95 mmHg) and inadequate dietary calcium intake (less than 750 mm/day), who were randomly assigned to placebo or 1500 mg/day elemental calcium for 4 weeks. Baseline and post-treatment urinary calcium concentrations and 3 biweekly supine blood pressures were recorded. Supine systolic blood pressure in the calcium group rose during the first 2 weeks of treatment (delta systolic blood pressure +5.9 mmHg; P less than 0.025) compared with no change in supine blood pressure for the placebo group. Within the calcium group, seven out of 15 patients had decreased or unchanged supine blood pressure during treatment. A lower urinary calcium concentration and a lower dietary sodium intake were found in this subgroup compared with those whose supine blood pressure increased with calcium administration.

Blood Pressure↗
PubMed1985

Noncompliance in screening follow-up among family planning clinic patients with cervical dysplasia.

This investigation estimated the extent of noncompliance with follow-up to screening for cervical dysplasia at a public health family planning clinic. Available data also permitted examination of the relationship between selected background characteristics and compliance with follow-up. Noncompliance was defined as failure to respond to notification of an abnormal cervical smear (Class III, IV, or V) by failing either to make a follow-up appointment or to keep such an appointment after it was made. The sample consisted of 177 women with abnormal cervical smears who were screened at the Forsyth County Family Planning Clinic between January 1, 1980, and June 30, 1981. Information on the women's compliance with the request for follow-up was obtained from a file specifically kept for this purpose by the clinic nurse. Background characteristics were obtained by reviewing clinic records. Results indicated that approximately 17% of the sample was noncompliant. Noncompliant patients were more likely to be unmarried, less educated, younger, and to have fewer total health problems than women who returned for follow-up. Logistic regression analysis revealed that the number of health problems and educational attainment were the most important predictors of noncompliance.

Adolescent↗
PubMed1985

Induction of mania by L-dopa in a nonbipolar patient.

The authors present a case of mania associated with the prolonged ingestion of large doses of L-dopa. Prior reports relating L-dopa therapy to mania in patients with bipolar disorders are discussed. The induction of a classic manic syndrome by catecholamine augmentation is possible in a nonbipolar individual.

Adult↗
PubMed1984

Coronary-prone behavior attitudes in moderate to severe coronary artery occlusion.

This study was undertaken to clarify the relationship between coronary artery occlusion (CAO) and coronary-prone behavior attitudes (CPBA) in a large coronary arteriography population. A group of 2451 male patients responded to a questionnaire prior to coronary arteriography. Ten questions from the questionnaire, selected to form a scale measuring CPBA, were found to be reliably associated with standard measures of Type A behavior. No differences in CPBA were found when the group was divided into mild, moderate, and severe CAO, but angina pectoris (AP) tended to increase from mild to severe CAO. Multiple regression analysis confirmed that CPBA were independently associated with AP but were not associated with CAO. These findings suggest that angina pectoris is an important intervening variable between CPBA and CAO and that the relationship of AP in a population should be carefully considered before conclusions are drawn as to the relationship between CPBA and CAO.

Angina, Unstable↗
PubMed1984

Psychological approaches to the management of arthritis pain.

The present review examines the literature regarding the efficacy of cognitive-behavioral and other self-control interventions in helping arthritis patients reduce their pain and functional disabilities. The evidence indicates that self-control interventions have produced significant and positive changes in the pain and functional disabilities of patients with rheumatoid arthritis and arthritis secondary to hemophilia. However, the literature suffers from deficiencies with regard to the use of small subject samples; inadequate control procedures and follow-up assessments; failure to demonstrate that positive outcomes are related to changes in subjects' covert experiences or control of physiological variables; and reliance upon self-report measures of outcome. The review is followed by a description of a multidisciplinary study of the efficacy of a biofeedback-assisted, cognitive-behavioral group therapy program for rheumatoid arthritis patients that features several methodological improvements relative to previous investigations. The preliminary outcome data show that the cognitive-behavioral intervention is associated with reductions in pain behavior and self-reports of pain and disability. It is concluded that, although the self-control interventions have shown promising results, psychologists must demonstrate positive and reliable outcomes among large numbers of arthritis patients over extended periods of time if the interventions are to be viewed as credible by rheumatologists.

Arthritis↗
PubMed1984

Lamb production and its components in pure breeds and composite lines. I. Seasonal and other environmental effects.

Season of lambing and other environmental effects on ewe performance were analyzed for purebred Finnsheep (F), Rambouillet (R), Dorset (D), Targhee (T) and Suffolk (S) and the generations of crosses in development of two maternal composite lines (1/2F1/4R1/4D) and (1/2F1/4T1/4S) in accelerated (January, May and September) or annual April lambing. The data involved 10,959 ewe breeding season records for 4,219 ewes of 412 sire families over 4 yr. Various measures of ewe productivity and its components (fertility, litter size, neonatal and preweaning survival and weaning weight) were analyzed. Fertility was higher for annual April than for accelerated May or January lambing and was sharply lower for September lambing. Fertility of F and F-cross ewes was significantly higher for May and lower for January lambings relative to R and D ewes. Litter size also was higher in annual April (1.9) than in January (1.8) or May (1.7) and September (1.4). Neonatal and preweaning survival was higher in September when litter size was smaller. Mean weaning weights were depressed in the larger April and May litters. Thus, weight of lambs weaned/ewe exposed was higher for annual April than for May and January lambing and was very low for September lambing. Hormone treatment of ewes for September lambing increased fertility from 16 to 44% and litter size from 1.6 to 1.8. Short lambing interval (8 mo vs 12+ mo) reduced mean ewe fertility by five percentage points, and most for the January lambing of Finnsheep ewes.

Animals↗
PubMed1984

Lamb production and its components in pure breeds and composite lines. II. Breed effects and heterosis.

Ewe performance was compared for five pure breeds of sheep (Finnsheep, F; Rambouillet, R; Dorset, D; Targhee, T; Suffolk, S) and the crosses in development of two maternal composite lines (C1 = 1/2F1/4R1/4D and C2 = 1/2F1/4T1/4S). The data involved 10,959 breeding season records of 4,219 ewes by 412 sires. Ewe production and the components (fertility, litter size, neonatal and preweaning lamb survival and mean lamb weaning weight) were adjusted for age and standardized across season of lambing and years. The D and F ewes produced more weight of lamb/ewe exposed than R, S and T ewes because of higher D and F fertility, higher D lamb survival and larger F litters. First cross and inter se generations of C1 and C2 ewes averaged 17 to 27% higher fertility than the parental mean. Litter size averaged about one lamb higher for F than for other pure breeds, but only slightly higher for C1 and C2 than for the mean of F and other breeds. Lower neonatal survival for F than for other breeds and crosses was associated with the larger F litters and with 2 to 8% positive heterosis in the crosses. Preweaning survival of suckled and nursery lambs was low for F and S and positive heterosis ranged from 9 to 19% in crosses. Mean lamb weaning weights were highest for S, lowest for F, with little heterosis in crosses. Crossbred ewes reared .3 to .4 more lambs than mean for parental pure breeds. Heterosis in C1 and C2 ranged from 11 to 28% for lambs born, 27 to 43% for lambs weaned and 29 to 44% for weight of lamb weaned/ewe exposed. Decline in heterosis with inter se mating of crosses was no greater than expected from the reduction in predicted heterozygosity.

Animals↗
PubMed1983

The use of cueing and positive practice in the treatment of tongue thrust swallowing.

Tongue thrust or reverse swallowing refers to the condition in which portions of the tongue rest or press against the teeth. In very severe cases the result can be dental malocclusion and/or speech difficulties. The present investigation evaluates the efficacy of cueing and positive practice in increasing the frequency of correct tongue position using a modified single subject withdrawal design with a 21 year old college student. The data indicate that the frequency of correct tongue positioning increased with the introduction of treatment. Follow-up data obtained 30 months post-treatment indicate that positive effects were being maintained.

Adult↗
PubMed1983

Reciprocal recurrent selection for 21-day litter weight of crossbred gilts. I. Selection applied and genetic change in reproduction of crossbred gilts.

Six cycles of reciprocal recurrent selection (RRS) between Line 8 (Duroc) and Line 9 (Beltsville No. 1) were completed at the Fort Reno Livestock Research Center, El Reno, Oklahoma. A randomly mated control line was maintained. Each cycle of selection required three seasons. Selection of purebred pigs (born in the second season) was based on the mean 21-d litter weight of their maternal and paternal half-sib crossbred gilts that were born in the first season and farrowed in the third season (XB21DLWT). On the average, 5.8 maternal and paternal half-sib gilts contributed to the mean XB21DLWT for each purebred individual. The average potential selection differential for XB21DLWT was 5.64 kg, but only 70.2% of this value was realized in the initial selection (3.95 kg). Disease problems and unsoundness were the primary reasons for this discrepancy. The potential, initial, final and weighted final standardized selection differentials for females averaged 61, 60, 55 and 47%, respectively, of the corresponding differentials for males. Standardized selection differentials were similar for Line 8 and Line 9. The estimate of realized heritability for XB21DLWT was .076 +/- .319 for the average of 8 X 9 and 9 X 8 gilts. Environmental trends, estimated from control data, were not significant for any of the traits evaluated. The genetic change in reproductive ability of 8 X 9, 9 X 8 and their unweighted average was estimated by regressing the deviation of the line mean from the control mean on generation number. In general, estimates of genetic change for litter size, litter weight and average pig weight/litter at 0, 21 and 42 d of age were not significant, but all estimates were favorable. The estimated genetic change for 21-d litter weight was 1.04 +/- 1.25 kg/cycle of selection. Based on these results and considering the complexity of RRS, the increase in generation interval and the expected decline in purebred performance that theoretically should accompany successful RRS, it seems doubtful that RRS can be more beneficial than selection based on purebred performance as a method to improve productivity of crossbred gilts.

Animals↗
PubMed1983

Reciprocal recurrent selection for 21-day litter weight of crossbred gilts. II. Reproductive performance of purebred females producing purebred and two-way cross litters and performance of purebred and crossbred pigs.

This paper reports estimates of correlated genetic change in reproductive performance of purebred gilts producing two-way cross litters and purebred sows producing purebred litters as well as postweaning performance of two-way cross and purebred pigs produced during reciprocal recurrent selection (RRS) between Line 8 (Duroc) and Line 9 (Beltsville No. 1) for 21-d litter weight production of crossbred gilts. A randomly mated control line developed from a crossbred foundation was maintained to monitor environmental change. Data were adjusted for age of dam, inbreeding of dam, inbreeding of litter (or pig) and linear and quadratic effects of day born within season. The traits evaluated were: litter size, litter weight and average pig weight/litter at birth and weaning (42 d); postweaning average daily gain; age at 90.7 kg and backfat thickness at 90.7 kg. Two data sets were analyzed; the first set included seven seasons of data with purebred gilts producing two-way cross litters, and the second set included seven seasons of data with purebred sows producing purebred litters. No estimates of environmental trend were significant in either set of data. In the first data set, only the estimate of genetic change in backfat thickness of two-way cross pigs was significant and it was in the desired direction. All other estimates were small and did not approach significance. In the second data set, estimates of genetic trend were greater in Line 9 than in Line 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗