PubMed Health⌕ Search

Biomedical subjects

J J Rutledge

Publications and source records attributed to J J Rutledge.

13 recordsLinked to original sources
PubMed1988

Influences of prenatal and postnatal fraternity size on ovarian development in the mouse.

An experiment was conducted to test effects of prenatal and postnatal fraternity size (size of litter in which an individual develops prenatally or is reared postnatally) on ovarian development in mice. Fraternity size treatments were created by standardizing sizes of prenatal and postnatal fraternities in which mice were gestated and reared. Prenatal fraternity size was standardized by surgery on Day 9 of gestation to 6, 10, and 14 fetuses. Postnatal fraternity size was standardized by randomly assigning pups to litters of 5, 10, or 15 pups within 24 h of birth. Female pups were killed at either 3 or 20 wk of age and right ovaries were prepared for histology. Follicles were classified by size and morphology, and numbers of follicles in each class were tabulated. Interaction of postnatal fraternity size and age was observed for number of antral follicles (p less than 0.05). Mice reared in small postnatal fraternities had more antral follicles at weaning (3 wk) and fewer antral follicles at maturity (20 wk of age) than mice reared in large postnatal fraternities. No effect of either prenatal or postnatal fraternity size on other follicle populations was observed (p greater than 0.20). Numbers of Type 2 (primordial), Type 3a, and Type 3b follicles changed with age (p less than 0.01); numbers of primordial follicles declined with age, but numbers of Type 3a and 3b follicles increased. A hypothesis of a negative association between postnatal fraternity size and number of antral follicles at 3 wk of age was supported, but a hypothesis of a positive association between fraternity size and number of primordial follicles was not supported.

Animals↗
PubMed1988

Influence of prenatal and postnatal fraternity size on reproduction in swine.

Hypotheses of a negative association between fraternity size (size of litter in which an individual develops prior to birth or is reared following birth) and ovulation rate or litter size were tested by examining reproduction of females born or reared in varying prenatal and postnatal fraternities. Gifts were randomly assigned to develop prenatally and be reared postnatal in small or large fraternities. Dams of experimental animals were randomly assigned to one of two prenatal fraternity size treatments, either unilateral oviductal ligation (to bear a small prenatal litter) or no ligation (to bear a normal prenatal litter). Whereas this did result in differences (P less than .01) in litter size at birth (small = 6.2 +/- .4 vs large = 9.6 +/- .9), there was considerable overlap in observed litter sizes between ligated and nonligated dams. Consequently, effects of prenatal fraternity size were examined by regression. Distinct differences in postnatal fraternity size were created by randomly assigning piglets to small (5 piglets) or large (10 piglets) postnatal fraternities within 24 h of birth. Differences in postnatal fraternity size were maintained through weaning at 3 wk (small = 4.9 +/- .1 vs large = 9.4 +/- .2). Weights at birth (regression of birth weight on prenatal fraternity size = -.07 +/- .02, P less than .01) and weaning (small = 6.09 +/- .15 vs large = 5.46 +/- .17 kg, P less than .01) were heavier for gilts from small prenatal and postnatal fraternities, respectively, compared with gilts from large fraternities. Effects of prenatal and postnatal size on BW did not persist following weaning (P greater than .20).

Animals↗
PubMed1988

Effects of prenatal and postnatal fraternity size on long-term reproduction in mice.

Effects of prenatal and postnatal fraternity size (size of litter in which an animal develops prior to birth or is reared following birth) on long-term reproduction were studied by rearing 178 female ICR mice in standardized prenatal and postnatal fraternities. Three levels of prenatal and postnatal fraternity sizes were used in a 3 x 3 factorial experiment. Prenatal fraternity size was standardized by selectively terminating fetal development in pregnant females carrying at least 14 conceptuses. Prenatal fraternities were standardized to either 6, 10 or 14 fetuses, and postnatal fraternities were standardized by randomly assigning individuals to nurse litters of 5, 10 or 15 pups. Prenatal fraternity size negatively affected average pup weight at birth (P less than .05) but had little subsequent effect on growth or reproduction. Postnatal fraternity size negatively affected weight at weaning (P less than .01), with mice reared in smaller postnatal fraternities being heavier than those reared in larger fraternities. Following weaning, mice reared in smaller fraternities gained weight less rapidly (P less than .01) but still tended to be heavier at maturity (P = .11). Vaginal opening occurred at older ages in females reared in larger postnatal litters (P less than .01). An interval mating system was used to examine fraternity size effects on long-term reproduction. Females were exposed to males six times at 8-wk intervals with initial mating at 7 wk of age. Postnatal fraternity size and age at mating jointly affected litter size (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The influence of prenatal and postnatal fraternity size on reproduction in mice.

Effects of prenatal and postnatal fraternity size (size of litter in which an individual is reared) on age at vaginal opening, growth, and subsequent litter production were examined by rearing mice in standardized prenatal and postnatal fraternities in a 3 X 3 factorial design. Prenatal fraternity size was standardized by reducing litters of 14 or more to either 14, 10, or 6 fetuses on Day 9 of gestation. Postnatal fraternity size was standardized by assigning pups randomly to nurse in litters of 5, 10, or 15 pups within 24 h of birth. Both prenatal and postnatal fraternity size affected growth of the mice (p = 0.02 and p less than 0.01, respectively) with mice reared in small fraternities attaining greater weights throughout the study. Prenatal fraternity size had a negative linear effect on litter size at second parity and tended to have a positive linear effect on age at vaginal opening. Postnatal fraternity size affected age at vaginal opening (p less than 0.01), litter size at first parity (p less than 0.01), and litter size at second parity (p = 0.03). These effects were positive and linear for age at vaginal opening (p less than 0.01; small fraternity size associated with younger age at vaginal opening) and negative and linear for litter size at first and second parity (p less than 0.01 and p = 0.10, respectively; smaller fraternity size associated with larger litter size). There was no interaction between prenatal and postnatal fraternity size effects on age at vaginal opening or litter size (p greater than 0.20).

Aging↗
PubMed1979

Impeded cerebellar development and reduced serum thyroxine levels associated with fetal alcohol intoxication.

Pregnant albino rats were placed on a complete liquid diet (Ensure) containing either 9% ethanol or an isocaloric amount of sucrose between the third and twentieth day of gestation. The pups born to these rats were sacrificed either day 11 or day 14 postnatum and morphometrical, histological and biochemical analyses were done on their cerebellums and cerebrums. Pups that were exposed to ethanol in utero had significantly smaller body weights, cerebrums and cerebellums than pair-fed controls. The cerebellar mass was reduced by 10% and the cerebral weight by 3% in the pups exposed to alcohol when body weights were normalized to that of pair-fed controls. Cerebellar aspartyl aminotransferase (EC 2.6.1.1) activity was reduced at day 11 and 14 in ethanol treated pups compared with controls. Serum T4 levels were also reduced in the ethanol treated group. Histological analyses revealed that the external granule cell (EGC) layer of ethanol treated pups was significantly thicker at 11 and 14 days postnatum than that of pair-fed control pups. Cerebellar ornithine decarboxylase (ODC, EC 4.1.1.17) activity was higher at day 11 in the ethanol treated pups than in controls. The reduced mass, AAT activity, T4 serum levels and the increased thickness of the ECG layer indicate a delayed or impeded maturation of cerebellum in ethanol treated pups. These data are considered from the viewpoint that ethanol, other drugs such as methadone and prenatal stress (malnutrition) may cause delayed cerebellar maturation by reducing serum T4 levels in the early postnatal period (day 5-14).

Alcohol Drinking↗
PubMed1979

Responses to selection for body weight in descendants of X-irradiated rats.

The effectiveness of selection for high and low body weight at six weeks of age was studied in descendants of X-irradiated (R) and nonirradiated (C) inbred rats. There were two replicates of each of the direction of selection-irradiation treatments. In C lines, there were no consistent responses to selection, probably due to a low level of genetic variability. In R rats, selection was effective only for decreased body weight. The results of this experiment do not suggest the use of irradiation combined with selection as a means of enhancing responses to selection in animals.

Age Factors↗
PubMed1979

Effect of age and parity on litter size in pigs.

Litter size increased (P less than 0.01) as the age of the dam at farrowing increased. However, previous reproductive experience (parity) had no direct effect on litter size of dams of the same age.

Animals↗
PubMed1977

Effects of ancestral X irradiation followed by random mating on body weight of rats.

Effects of nine generations of 450r per generation of ancestral spermatogonial X irradiation of inbred rats on body weight were examined. After six generations of random mating (avoiding inbreeding) following the termination of irradiation, descendants of irradiated males (R) were significantly lighter than their controls (C) at 3 and 6 weeks, but not at 10 weeks of age. However, differences in growth between R and C populations were small. Among-litter and within-litter variance estimates were generally larger in the R lines than in the C lines, suggesting that selection responses would be greater in R than in C lines. In conjunction with previous evidence--obtained during the irradiation phase of the experiment--this suggested that more rapid response to selection for 6-week body weight, in particular, might accrue in the R lines.

Animals↗
PubMed1977

Estimates of genetic parameters of body weight in descendants of X-irradiated rat spermatogonia.

Effects of nine generations of 450r per generation of ancestral spermatogonial X irradiation of inbred rats on genetic parameters of body weight at 3, 6, and 10 weeks of age and of weight gains between these periods were studied. Covariances among relatives were estimated by mixed model and regression techniques in randomly selected lines with (R) and without (C) radiation history. Analyses of the data were based on five linear genetic models combining additive direct, additive indirect (maternal), dominance and environmental effects. Parameters in these models were estimated by generalized least-squares. A model including direct and indirect genetic effects fit more closely to the data in both R and C lines. Overdominance of induced mutations did not seem to be present. Ancestral irradiation increased maternal additive genetic variances of body weights and gains but not direct genetic variances. Theoretically, due to a negative direct-maternal genetic correlation, within full-sib family selection would be ineffective in increasing body weight at six weeks in both R and C lines. However, progress from mass selection would be expected to be faster in the R lines.

Aging↗
PubMedDate not supplied

Genetic analysis of crossfostering data with sire and dam records.

A method is presented for the analysis of data from crossfostering experiments in which parts of litters are reciprocally interchanged at birth. Observed variances and covariances of differently related individuals are expressed as functions of theoretical causal components of phenotypic variance (additive direct, dominance direct, additive maternal, dominance maternal, direct-maternal covariance, and environmental). Causal components are estimated by weighted least squares analysis of this system of equations, including a ridge-regression procedure to examine consequences of correlation between observed components. Ridge regression suggests that dominance direct genetic variance is generally underestimated, but that narrow-sense heritability estimates are reliable.

Animals↗