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Biomedical subjects

P J Dziuk

Publications and source records attributed to P J Dziuk.

At least 19 recordsLinked to original sources
PubMed1999

Concentrations of free steroids in the jugular and hepatic portal veins of pigs after ingestion of testosterone, estrogen, or progesterone or transplantation of ovaries to the intestine.

Estrogen, progesterone or testosterone were administered orally to ovariectomized gilts fitted with indwelling catheters. Blood samples were taken from the jugular and hepatic portal veins at intervals varying from a few minutes to daily over periods that varied from 1 d to several months. Concentrations of free steroids rose dramatically in the hepatic portal vein within a few min of feeding steroids and remained high for 3-8 hr before declining to base levels. Concentrations in the jugular vein sometimes rose very slightly for the same period. At 48 hr after administration the concentrations remained at baseline in the hepatic portal vein, but rose several-fold in the jugular and remained elevated for several days. Autotransplantation of the ovaries to the intestine resulted in very large ovaries consisting of many large, heavily luteinized cystic follicles. Concentrations of progesterone and estrogen in the hepatic portal vein were very high, but were low in the jugular vein. The gut wall allows for passage of some orally administered free steroids to the liver via the hepatic portal vein. The free steroids are essentially metabolized before they reach the jugular vein, but can be recirculated via the enterohepatic route.

Administration, Oral↗
PubMed1995

Effects of relaxin administration in early gestation or prior to mating on uterine length and fetal survival in gilts.

The objective of this research was to determine the effect of administration of porcine relaxin to gilts during early gestation, or during the follicular phase of the estrous cycle immediately preceding mating, on the length of the uterus and consequently the number of surviving fetuses. Experiment 1 determined the individual and combined effects of 10 days of administration of relaxin (0.5 mg, 4 times daily), estradiol benzoate (1 mg, 2 times daily), and progesterone (50 mg, 2 times daily) on uterine wet weight and length in 58 ovariectomized 8-mo-old pubertal gilts. Relaxin alone had no effect on either uterine length or wet weight. Estrogen increased uterine wet weight, and this effect was augmented by relaxin. Progesterone increased uterine length, and this effect was augmented by estrogen. Combined treatment with progesterone, estrogen, and relaxin increased both uterine length and wet weight maximally. Experiment 2 determined the effects of relaxin administration in early gestation or prior to mating on uterine length and fetal survival in 75 unilaterally ovariectomized-hysterectomized gilts. Relaxin (0.5 mg, 4 times daily) was administered during three treatment periods, and uteri were collected on Day 40 of gestation. In this study, relaxin administration from Days 11 to 20 of gestation reduced the number of live fetuses (p = 0.01) and percentage survival (p = 0.01) and resulted in shorter uterine length (p = 0.01) and lower uterine wet weight (p = 0.03) than in controls, but did not affect length of uterus or uterine dry weight. Relaxin administration from Days 22 to 31 of gestation did not influence fetal survival, uterine length, uterine length per fetus, uterine wet weight, or uterine dry weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Circulation of estrogens introduced into the rectum or duodenum in pigs.

To determine the absorption and metabolism of 17 beta-estradiol (E2) by the rectum of the pig, 10 mg of crystalline E2 was placed in the rectum of prepubertal gilts in Experiment 1. Blood samples were subsequently obtained from hepatic portal and jugular veins and plasma was assayed for E2, estrone (E1), 17 beta-estradiol-glucuronide (E2G), estrone-glucuronide (E1G) and estrone-sulfate (E1S). Concentrations of E2, E1, E2G, E1G, and E1S rose in the hepatic portal vein within 30 min and remained elevated for several hr. Concentrations of E2 in the hepatic portal vein represented 3% of the total estrogen detected in the hepatic portal vein during the 5 hr sampling period, indicating that most of the E2 was metabolized prior to entering the hepatic portal vein after absorption by the rectal mucosa. Concentrations of E2, E1, E2G, E1G, and E1S rose in the jugular vein and remained elevated for several hr. The rise in E2 and E1 in the jugular vein may have come from E2 and E1 in venous circulation from the rectum that entered the inferior vena cava bypassing the hepatic portal vein and liver. The net result of absorption of E2 from the rectum of gilts was a large rise in unconjugated and conjugated E2 and E1 in the peripheral circulation. In Experiment 2 prepubertal gilts fitted with jugular, hepatic portal, duodenal, and gall bladder catheters were infused into the duodenum with bile from pregnant gilts. Concentrations of E2, E1, E2G, and E1G were determined in gallbladder bile of gilts before infusion and at 470 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Rectal↗
PubMed1994

Absorption and metabolism of estrogens from the stomach and duodenum of pigs.

To determine the absorption and metabolism of 17 beta-estradiol (E2) by the stomach and liver of the pig, crystalline E2 was placed in the stomach of prepubertal gilts. Blood samples were subsequently obtained from the hepatic portal and jugular veins and plasma was assayed for E2, estrone (E1), 17 beta-estradiol-glucuronide (E2G), estrone-glucuronide (E1G) and estrone-sulfate (E1S). Concentrations of E2, E1, E2G and E1S rose in the hepatic portal vein within five min and remained elevated for several hr. Concentration of E2 represented only 6% of the total estrogen detected in the hepatic portal vein during the sampling period, indicating that most of the E2 was converted or conjugated prior to entering the hepatic portal vein. The metabolism of E2 presumably occurred in the stomach mucosa because food had been withheld for 26 hr before infusion of E2. Concentrations of E2G, E1G and E1S, but not E2 and E1, rose in the jugular vein and remained elevated for several hr. The lack of a rise in E2 and E1 in the jugular vein indicates that the E2 and E1 from the hepatic portal vein were completely converted and/or removed by the liver. Most of E2 was converted to E1 and then to E1G. The infusion of bile containing normal estrogens from pregnant gilts into the duodenum of prepubertal gilts resulted in a peak of E1G and E2G in the hepatic portal and jugular veins within a few minutes. This was followed in about 180 min by a second sustained rise. The first peak was essentially abolished by extracting E1 and E2 from the bile before infusion. The second peak failed to occur in gilts given antibiotics orally to reduce gut bacteria before infusion of bile.

Absorption↗
PubMed1993

Age at puberty, ovulation rate, uterine length, prenatal survival and litter size in Chinese Meishan and Yorkshire females.

Studies on the ovulation rate, prenatal survival and litter size of Chinese Meishan pigs have given widely divergent results depending on the extent of inbreeding of the animals, their original genetic diversity, the age and parity, and the conditions of management. To obtain meaningful results, it is necessary to characterize the population under study. The following report characterizes populations of Meishan and Yorkshire of a widely diverse background. First farrowing data were collected on 21 Meishan and 20 Yorkshire gilts. Meishan gilts had 12.4 fully formed piglets and Yorkshire gilts had 7.4 fully formed piglets (P < 0.01). Meishan gilts averaged 1.86 mummified fetuses per litter vs 0.05 per Yorkshire litter (P < 0.01). Yorkshire piglets averaged 1.3 kg body weight at birth vs 0.9 kg for Meishan piglets (P < 0.01). At 47 days of second gestation, 19 Meishan and 12 Yorkshire sows averaged 22.7 and 16.3 corpora lutea (CL), respectively (P < 0.01). Uterine length and number of fetuses were not different (P > 0.40) in the two breeds. Daily estrous detection of 50 Meishan and 34 Yorkshire gilts began at 60 and 120 days of age, respectively. Meishan gilts reached sexual maturity at 95 days of age, which was 105 days earlier than Yorkshire gilts (P < 0.01). Meishan gilts were in estrus nearly 1 day longer than Yorkshire gilts at first, second and third estrus (P < 0.05). No differences in cycle length between breeds were detected for the first or second estrous cycle (P > 0.60). Nineteen Meishan gilts were slaughtered at 51 days of gestation and their reproductive tracts were recovered. The mean number of dissected CL (17.0), number of fetuses (13.1), total uterine length (396 cm), spacing per fetus (29.9 cm), allantoic (124.9 ml) and amniotic (32.2 ml) volumes, crown-rump length (82.8 mm), weight (35.4 g), sex, and direction of each fetus were determined. Chinese Meishan gilts reached puberty much earlier and were in estrus longer than Yorkshire gilts and Meishan sows had more CL than Yorkshire sows.

Journal Article↗
PubMed1993

Effect of concentration of mixed-function oxidase on concentration of estrogen, rate of egg lay, eggshell thickness, and plasma calcium in laying hens.

The objective of this study was to investigate the effect of induction or depression of mixed-function oxidases (MFO) by xenobiotics on the peripheral concentration of estrogens, plasma Ca, rate of egg lay, and eggshell thickness in laying hens. In Exp. 1, 100 mg of phenobarbital (PB) administered orally each day for 3 or 7 d reduced concentrations of estrone and estradiol (E2) in serum. In Exp. 2, 25, 50, or 100 mg of PB was administered orally to laying hens for 3 or 7 d. Treatment with 100 mg of PB for 3 d or with 25, 50, or 100 mg for 7 d significantly increased liver:body weight ratios. Microsomal protein increased after 7 d of 50 or 100 mg of PB administration. Feeding PB decreased concentration of E2 and total plasma Ca in a dose- and period-dependent manner. Concentration of E2 was reduced to 10% of control, whereas hepatic cytochrome P-450 increased significantly with dose. The correlation between concentration of E2 and P-450 was negative and significant. Total Ca in the plasma was highly, positively correlated with concentration of E2. Eggshells were thinner from hens treated with 100 mg of PB for both 3 or 7 d than those from control hens. Rate of egg lay was reduced by 100 mg of PB for 7 d. In Exp. 3, .5 mL of CCl4 given orally for 1 d decreased P-450 and increased E2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Influence of initial length of uterus per embryo and gestation stage on prenatal survival, development, and sex ratio in the pig.

The effects of uterine length per embryo and stage of gestation on prenatal survival, development, and sex ratio were determined by systematically restricting embryos to 5, 10, 15, 20, 25, 30, 35, 40, 45, or > 50 cm of initial uterine length per potential embryo and examining the reproductive tracts at d 17, 23, 29, 35, or 41 of gestation. At d 3 the mean length of a uterine horn was 169 +/- 35 cm, with a range of 80 to 255 cm. The mean total number of corpora lutea (CL) was 12.4 +/- 2.34. Ovulation rate tended to be correlated with the length of uterine horns (r = .38; P > .1). Prenatal survival was highly correlated with initial assigned uterine space from 5 to 25 cm/CL (r = .95; P < .05). Prenatal survival was not affected by space (r = .53; P < .1) when space was > 25 cm/CL. In all groups, regardless of space available, some prenatal loss occurred before d 17. In sections with < 25 cm/CL, a second loss took place between d 29 and 35. Before d 35, there was no significant effect of restriction on either fetal length or weight, but after d 35, fetuses from sections with > 25 cm/CL were longer and heavier than those from sections with less space (P < .05). Greater uterine space was occupied by larger fetuses (P < .05). Male fetuses occupied more uterine space than female fetuses did in both crowded and roomy sections (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

An embryo transfer study of reciprocal cross differences in growth and carcass traits of Duroc and Landrace pigs.

Reciprocal cross differences have been reported for growth rate and carcass traits in F1 pigs with the Duroc (D) as a parent breed. Such differences are synonymous with maternal effects if effects of sex linkage and genomic imprinting are negligible. In the present study, transfer of embryos (ET) to paternal breed recipients partitioned effects occurring at or before fertilization from postfertilization effects for growth and carcass traits in F1 D-Landrace (L) pigs. Fifteen boars sired 115 F1 litters, 49 produced by ET. Growth rate of 349 barrows and 361 gilts and carcass measurements on 256 barrows and 159 gilts were analyzed assuming mixed linear models with animal and litter as random effects. Contrasts among genotype (D x L, L x D)- treatment (ET, non-ET) means were tested. Reciprocal cross differences were not detected for growth rate or for carcass weight, length, average backfat thickness, estimated carcass lean, or lean per day of age. Reciprocal cross differences for 10th rib backfat thickness (BF) and longissimus muscle area (LMA) were detected only in barrows. The sexual dichotomy for reciprocal cross differences followed expectations for a Y-linked gene(s), consistent with the fact that reciprocal D-L crossbred barrows exhibited a paternal effect, with responses more like the sire breed than the dam breed. Barrows that were non-ET from D sires and L dams had 3.9 cm2 larger LMA and 5.8 mm less BF than barrows from L sires and D dams (P less than .001). Barrows from ET sired by D boars had 3.8 cm2 larger LMA than did barrows from ET sired by L boars (P less than .001), although no difference was detected for BF. Barrows sired by D boars reared in a D postfertilization environment (ET) had 6.2 cm2 greater LMA and 4.1 mm less BF (P less than .05) than barrows sired by L boars gestated and reared by D dams (non-ET). Barrows sired by D boars reared by L dams (non-ET) had 1.5 cm2 greater LMA and 2.3 mm less BF (P greater than .10) than barrows sired by L boars reared by L dams (ET). In conclusion, reciprocal cross differences detected for BF and LMA in barrows were established before or at fertilization and seemed to be Y-linked.

Adipose Tissue↗
PubMed1991

Hormonal control of the cervix in pregnant gilts. III. Relaxin's influence on cervical biochemical properties in ovariectomized hormone-treated pregnant gilts.

The effects of relaxin on the biochemical properties of both the uterine and vaginal portions of the cervix were examined between days 80-110 of pregnancy in ovariectomized gilts given progesterone to maintain pregnancy. In the cervix of control gilts and those ovariectomized and given progesterone plus relaxin, wet and dry weights, water content, and the glycosaminoglycan/collagen ratio increased between days 80-110 of gestation. Collagen concentrations based on wet or dry weight and glycosaminoglycan concentrations based on wet weight decreased during this period. After ovariectomy, there were no changes in these cervical connective tissue components when relaxin was not given. The glycosaminoglycans hyaluronic acid, heparan sulfate, and dermatan sulfate were found in the cervices of all treatment groups, with dermatan sulfate predominating. The ratio of the individual glycosaminoglycans did not change during pregnancy or with treatment. The major dermatan sulfate proteoglycan from the pig cervix was isolated and found to be similar in size, immunoreactivity, amino acid composition, and amino acid sequence to the major dermatan sulfate proteoglycans isolated from the cervices of other mammals. It is concluded that the relaxin-induced changes in the connective tissue composition of the cervix may contribute at least in part to increased extensibility and growth of the cervix during the last third of gestation in pigs.

Animals↗
PubMed1991

Effect of number of corpora lutea and fetuses on concentrations of progesterone in blood of goats.

The objectives of this study were to assess relationships between 1) number of corpora lutea (CL) and concentrations of progesterone (P) in plasma of goats from onset of estrus (d 0) to d 45 of pregnancy and 2) concentration of P and number of fetuses on d 45. Blood from 79 pregnant goats was obtained on d 0 and 1 and at 48-h intervals thereafter to d 25 of gestation. Additional samples were collected every 5 d from d 25 to d 45. Plasma samples were analyzed for P by RIA. Fetuses and CL were counted at laparotomy on d 45 +/- 3. Six does had one CL, 47 had two and 26 had three or four. Concentrations of P were compared for 1) animals with different numbers of CL and 2) animals with the same number of CL but different numbers of fetuses on d 45. Concentration of P increased in all animals from d 3 to a maximum of 8.5 +/- .3 ng/ml on d 13, then P declined to 5 +/- .3 ng/ml by d 35. Goats with multiple CL had higher P than goats with one CL (P less than .01) from d 7 to d 30. Of goats with two CL, those with two fetuses at d 45 had higher P on d 13 than those with one fetus (P less than .01). The number of CL or fetuses did not influence the concentration of P after d 30.

Animals↗
PubMed1990

Behavioral and endocrine responses of sows to prostaglandin F2 alpha and cloprostenol.

Behavioral and endocrine changes in the sow following injection with prostaglandin F2 alpha (PGF2 alpha) or its analogue, cloprostenol (CLO), were monitored to identify endocrine correlates of prepartum activity (nest-building). On Day 112 postcoitum, within 15 min after injection with 10 mg PGF2 alpha, sows offered straw in pens engaged in intense prepartum activity, but few behavioral changes occurred during the first 2 h following administration of 175 micrograms CLO. The temporal pattern of prepartum activity, however, was affected by both prostaglandins. In control sows, most prepartum activity came during Hours 16-0 before delivery of first piglet (delivery). After CLO, sows engaged in nest-building more during Hours 32-17 and less during Hours 16-0. In another experiment, sows in farrowing crates were injected with saline, 175 micrograms CLO, or 10 mg PGF2 alpha on Day 112 and blood was collected 0, 15, 30, 60, and 90 min later. Another sample was collected when spontaneous prepartum activity was first observed. For approximately 90 min after PGF2 alpha treatment, sows rooted, pawed, and bit and rubbed faces on crate bars; after saline and CLO, this behavior was rarely observed. After prostaglandin treatment, plasma progesterone tended to decline, a 10-fold rise in relaxin came within 15 min, but estrone did not change. Plasma prolactin rose 10-fold within 30 min after PGF2 alpha treatment, and rose more gradually after CLO treatment. When sows exhibited spontaneous prepartum activity (approximately 7 h before delivery), endocrine status was characterized by low progesterone, high estrone:progesterone ratio, and high prolactin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Hormonal control of the cervix in pregnant gilts. II. Relaxin promotes changes in the physical properties of the cervix in ovariectomized hormone-treated pregnant gilts.

The effects of relaxin on the physical properties of both the uterine and vaginal portions of the cervix were studied between days 80 and 110 of pregnancy in ovariectomized gilts given progesterone to maintain pregnancy. In controls gilts the extensibility, lumen diameter, and wet weight of the uterine portion of the cervix were less than those of the vaginal portion of the cervix on day 80, but increased thereafter, and by day 110 did not differ (extensibility and wet weight) or approached (lumen diameter) those values of the vaginal portion of the cervix. When gilts were ovariectomized on either days 80 or 100 and given progesterone only (groups OP-100 and OP-110) extensibility, lumen diameter, and wet weight failed to increase in both the uterine and vaginal portions of the cervix. After replacement therapy with progesterone plus relaxin (groups OPR-100 and OPR-110), extensibility, lumen diameter, and wet weight increased to values as least as large as those in control groups in both portions of the cervix. In all groups the uterine portion of the cervix changed more dramatically than the vaginal portion. After hormone replacement therapy, blood levels of relaxin were moderately higher, and blood levels of progesterone were somewhat lower than those in control gilts. There was little or no difference in estrogen levels between ovariectomized and control gilts. We conclude that relaxin plays an important role in promoting increased growth and extensibility in both the uterine and vaginal portions of the cervix after day 80 of gestation in the gilt.

Animals↗
PubMed1989

Effect of initial length of uterus per embryo on fetal survival and development in the pig.

Influence of initial length of uterus available to each embryo on its subsequent survival and development was determined by systematic restriction of the length available to each potential embryo. Fifty-seven pregnant crossbred gilts were laparotomized at d 3 of gestation, length of uterine horns was measured in situ and corpora lutea (CL) were counted. In Exp. 1, uterine space available to each potential embryo was restricted by ligating one uterine horn 5 cm from the tip per CL. Uteri were examined at d 20, 25 or 50. In Exp. 2, one uterine horn was ligated on d 3 at 10, 20 or 30 cm from the tip per CL and uteri were examined at d 50. Embryos in the restricted section (RS) had a specific mean uterine length available to each potential embryo of 5, 10, 20 or 30 cm. Embryos in the nonrestricted section (NRS) had a variable mean uterine length available to each potential embryo of 44 +/- 4 cm. When embryos were restricted to 5 cm, the proportion of surviving fetuses at d 20, 25 and 50 was 61, 12 and 8%, respectively, whereas in combined NRS it was 82%. When the uterus was examined at d 50 after restricting embryos to 10, 20 or 30 cm/CL, 25, 33 and 52% of fetuses survived; in combined NRS survival was 71%. Each fetus surviving to d 50 in RS was associated with 36 cm of initial uterine length but fetal survival was not associated with number of CL. In RS, 59% were female fetuses and in NRS 50% were females.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Comparison of heterospermic and homospermic inseminations as measures of male fertility.

This study attempted to determine a basis for the previously observed greater sensitivity of heterospermic tests when compared to homospermic tests for detecting differences in fertility between males. In theory, the results of heterospermic tests are an indication of the proportion of eggs fertilized per unit time whereas results of homospermic inseminations measure only the cumulative or final proportion of eggs fertilized. The fertilizing ability of sperm from males of CF1 and C57BL/6N strains of mice was compared homospermically using both relatively high and low concentrations of sperm and by measuring the proportion of eggs penetrated per unit of time. The fertilizing ability of sperm from these strains was also compared using heterospermic inseminations. When females were inseminated with a high concentration of sperm, males of both strains fertilized a high and indistinguishable percentage of eggs when examined after 30 hr. When females were inseminated with either a low concentration of sperm or when the proportion of eggs penetrated was measured at 5 hr, differences between strains of mice were distinguishable. Heterospermic insemination further magnified the observed difference between strains. The results of this study confirm that measuring the percentage of eggs fertilized per unit of time can enhance the magnitude of differences between males in fertility as compared to measuring only the final percentage of eggs fertilized. Measuring the percentage of eggs fertilized per unit of time does not, however, entirely account for the large differences observed between fertility of males when they are compared using heterospermic inseminations.

Animals↗
PubMed1988

Ovarian influence on uterine growth in prepubertal gilts.

A determination of age of the prepubertal gilt at which ovaries affect uterine growth is necessary before establishing the extent to which length of uterus is influenced by inherent differences, as opposed to those due to ovarian secretions. In Exp. 1 and 2, the effect of presence of ovaries on uterine growth was determined following ovariectomy in 186 crossbred gilts. The uterus was examined 40 or 80 d after ovariectomy for length, weight and diameter. Growth of uterine horns in gilts from 20 to 60 d of age was equal with or without ovaries. Uterine horns in ovariectomized gilts continued to grow slowly from 60 to 140 d of age and then remained static to 180 d of age. Uterine horns in gilts with ovaries increased rapidly in length, weight and diameter, with concomitant increase in ovarian weight between 100 and 180 d of age. In Exp. 3, uterine growth and ovarian compensation after unilateral ovariectomy and hysterectomy at 60 d of age were determined in 85 crossbred gilts from 60 to 180 d of age to evaluate the unilateral ovariohysterectomy model for studying association of uterine length before puberty and subsequent uterine capacity. In response to removal of an ovary and a uterine horn, the remaining ovary compensated, but the remaining uterine horn did not. This study demonstrated that the ovaries did not influence uterine growth until after 60 d of age and that unilateral ovariohysterectomy could be performed as early as 60 d of age without altering consequent normal uterine growth.

Animals↗
PubMed1988

Effect of stage of gestation, litter size and uterine space on the incidence of mummified fetuses in pigs.

Factors associated with incidence of mummified fetuses at 7, 9, 11, 13 and 15 wk of gestation were determined in a cross-sectional design involving 209 pregnant pigs. Percentage of observed mummies increased from 2.1 to 12.2% as gestation progressed. Incidence of mummies at 7 wk of gestation was not different between litters of nine fetuses or fewer and those of 10 fetuses or more. During the period of 7 to 15 wk of gestation, the incidence of mummies remained constant at about 1% in litters of nine fetuses or fewer, whereas in litters of 10 fetuses or more the incidence increased linearly from 1 to 12% (P less than .01). In litters of nine fetuses or fewer, a mummy occupied no less space than a live fetus until 13 wk of gestation. In litters of 10 fetuses or more, a mummy occupied less space than did a live fetus after 7 wk of gestation. An increase in the incidence of mummies in larger litters was associated with uterine space per fetus below that needed for development and survival. The 12% fetal loss in late gestation was associated with less uterine space per fetus. Length of uterine horns, litter size and stage of gestation together accounted for 12% of the variation in incidence of mummies (P less than .001). A longer uterus had greater space per fetus, a larger number of live fetuses and a lower incidence of mummies.

Animals↗