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Biomedical subjects

D A Coleman

Publications and source records attributed to D A Coleman.

At least 37 records · Page 2Linked to original sources
PubMed1993

Neonatal porcine endometrial development involves coordinated changes in DNA synthesis, glycosaminoglycan distribution, and 3H-glucosamine labeling.

To determine whether neonatal porcine endometrial development involved alterations in endometrial DNA synthesis, glycosaminoglycan (GAG) distribution, and/or 3H-glucosamine labeling, gilts were assigned randomly at birth (Day 0) to be hysterectomized on either Day 0, 7, 14, 28, 42, or 56. Uteri were processed for histology and Alcian blue-8GX (AB) histochemistry or cultured as explants in the presence of [methyl-3H]thymidine (3H-Thd) or D-[6-3H]glucosamine (3H-GlcN) and processed for subsequent autoradiography. For 3H-Thd-labeled tissues, labeling index (LI; % of nuclei labeled) was determined for two endometrial tissues (epithelium and stroma); two epithelial areas (luminal and glandular); and, for glandular epithelium, in three endometrial zones (zone 1 = shallow, zone 2 = intermediate, zone 3 = deep). For 3H-GlcN-labeled tissues, LI (grains/100 microns2) was determined for two stromal zones (shallow and deep). Endometrial glands were absent on Day 0, present in shallow stroma on Days 7 and 14, and extended to the myometrium in tissues from Day 28 through Day 56. Appearance of endometrial glands was associated with a dramatic increase in glandular epithelial 3H-Thd LI, which was maximal on Days 7 and 14 and declined thereafter. When glands were present in all three endometrial zones (Days 28-56), glandular epithelial 3H-Thd LI was consistently greatest in zone 2. Stromal 3H-Thd LI decreased after Day 0. In tissues obtained after Day 0, a distinct zone of alcianophilia was observed in shallow stroma adjacent to luminal epithelium and surrounding the necks of newly developed endometrial glands. This staining pattern was marked in tissues from Days 7, 14, and 28. Generally, stromal 3H-GlcN LI was greater in shallow than in deep stromal zones; it decreased after Day 0 to minimum values on Days 28 and 42 in both zones, and increased slightly in shallow stroma on Day 56. Data indicate that development of the neonatal porcine endometrium between birth and Day 56 involves coordinated alterations in patterns of DNA synthesis, GAG distribution, and glycoconjugate biosynthesis. The morphogenetic processes characterized here are likely to be regulated locally via changes in tissue microenvironment.

Animals↗
PubMed1993

Effect of endotoxin on pituitary hormone secretion in sheep.

Endotoxin, a potent stimulator of the immune system and an important mediator in the pathophysiology of septic shock, has been shown to alter the release of certain hormones following its systemic administration. The purpose of this study was to determine the effects of endotoxin on pituitary hormone secretion both in vivo and in vitro in sheep, with emphasis placed on its effects on growth hormone (GH) release. Endotoxin (400 ng/kg i.v.) increased plasma GH, adrenocorticotropic hormone (ACTH), cortisol and prolactin, while it decreased luteinizing hormone (LH) pulse frequency (p < 0.05). Plasma levels of tumor necrosis factor, a major mediator of endotoxin effects, also increased following endotoxin administration. Endotoxin did not affect the GH response to human GH-releasing hormone. In vitro studies evaluated the effect of endotoxin to alter GH secretion from dispersed sheep anterior pituitary cells at dosages of 1, 10 and 50 micrograms/ml, with samples collected at 4, 8 and 24 h. Endotoxin increased pituitary GH secretion at 24 h for 1 microgram/ml (p < 0.05) and at all time periods for 10 and 50 micrograms/ml (p < 0.05). It also led to an increased release of ACTH and LH in vitro. The results of this study demonstrate the ability of endotoxin to alter pituitary hormone secretion both in vivo and in vitro in sheep, suggesting a direct effect of endotoxin on the pituitary gland.

Adrenocorticotropic Hormone↗
PubMed1992

Hepatitis kills.

Explore the source record for details and available documents.

Education, Nursing, Continuing↗
PubMed1990

Pre- and postoperative imaging of vascularized fibular grafts.

Free vascularized fibular grafting, in which the peroneal artery is harvested with the fibula, is a popular procedure for filling osseous defects and for treatment of femoral head avascular necrosis. Preoperative vascular imaging is required in all patients to detect the origin of the peroneal artery, to measure the length available for the vascular pedicle, and to evaluate for the normal continuation of the three major vessels of the lower leg. Magnetic resonance imaging of the lower leg with use of gradient-recalled acquisition in a steady, state was performed in 35 patients to evaluate vascular anatomy. Surgical correlation was available in 91% of cases, and in these 100% accuracy was demonstrated. Postoperative radiographs showed that grafts placed for osseous defects in the upper extremity were incorporated and hypertrophied extremely quickly, while those placed in the major weight-bearing bones of the lower extremity were much more prone to complications including delayed union, fracture, and infection. Vascularized grafts placed in the femoral head and neck for avascular necrosis incorporate only in the cephalic portion and should be watched carefully for signs of early and progressive femoral head collapse.

Adolescent↗
PubMed1990

Effects of 21-day treatment with melengestrol acetate (MGA) with or without subsequent prostaglandin F2 alpha on synchronization of estrus and fertility in beef cattle.

Beef cattle were treated to synchronize estrus using one of three procedures, and effects on subsequent endocrine responses and fertility were studied. Procedures were 1) feeding .5 mg.head-1.d-1 of melengestrol acetate (MGA) for 21 d (M), 2) feeding .5 mg.head-1.d-1 of melengestrol acetate for 21 d followed 14 d later by a single injection of prostaglandin F2 alpha (M + P) and 3) two injections of prostaglandin (PGF) 14 d apart (P). In Exp. 1, 94 beef cows were assigned to be artificially inseminated 12 h after detection of estrus. Procedures for synchronizing estrus did not affect the proportion of cows observed in estrus within 7 d (mean = 70.2%). However, conception rate of cows treated with MGA alone was lower (P less than .01) than that of cows treated with PGF alone (31.8 vs 78.3%). The conception rate of cows in the M + P group was intermediate (57.1%) but greater than that of cows treated with MGA alone (P less than .10). In Exp. 2, 18 heifers were observed for estrus four times daily and bled daily from 1 wk before predicted estrus until second estrus or 35 d post-treatment. Heifers treated with MGA alone maintained lower concentrations of progesterone and higher concentrations of estradiol-17 beta before first estrus than heifers treated with MGA and PGF or PGF alone (P less than .01). Conception rate following insemination was lower after long-term feeding of MGA than after two injections of PGF. Delaying insemination until after a PGF-shortened cycle 14 d after MGA resulted in an intermediate conception rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Magnetic resonance imaging of vascular anatomy before vascularized fibular grafting.

Magnetic resonance images of the leg were made preoperatively to show the vascular anatomy in twenty-nine patients (thirty-five legs) who were between the ages of fourteen and forty-one years and in whom we planned to use the fibula as a vascular graft. The fibula was harvested as a graft in thirty-two legs, and this allowed us to compare the images with the anatomical findings at operation. In these thirty-two legs, the branching pattern, the measured distance to the bifurcation of the peroneal artery, and all vascular anomalies in the area were accurately detected. No graft was taken from the other three legs. We recommend that imaging of the vascular anatomy of the leg be done before using the fibula as a vascular graft in order to detect the precise point of origin of the peroneal artery from the posterior tibial artery, to estimate the length of the vascular pedicle, and to evaluate the role of the three major vessels in supplying blood to the leg. All these aims can be accomplished with the aid of angiography, but we have found that gradient-recalled acquisition in the steady state (GRASS) magnetic-resonance imaging is more cost-effective and is associated with less morbidity. It is not adequate for older patients who have arterial stenosis or atherosclerosis or for patients who have some other underlying vascular disease. Metallic hardware may cause artefacts that obscure the vascular anatomy.

Adolescent↗
PubMed1989

Human bite wounds.

Human bite injuries, as innocuous as they may initially appear, may result in severe impairment. With a better understanding of the anatomy, microbiology, mechanism of injury, and clinical presentation, early diagnosis and the institution of appropriate therapy may minimize the morbidity commonly associated with human bite infections of the hand.

Bites and Stings↗
PubMed1988

Endocrine and reproductive responses of beef cattle to a synthetic gonadotropin-releasing hormone agonist (fertirelin acetate).

A synthetic gonadotropin-releasing hormone (GnRH) agonist (fertirelin acetate, FA) was administered to beef cattle within 12 h after onset of estrus (Day = 0) to study effects on subsequent endocrine responses and fertility. In Study 1, 16 crossbred beef heifers were injected with either 100 mug FA (n = 8) or saline (n = 8) at 6 or 12 h (n = 7; n = 9) after onset of estrus. Concentrations of luteinizing hormone (LH) over time were affected (P<0.01) by the interaction of treatment and interval from onset of estrus to treatment. Heifers treated with FA at 6 h after onset of estrus exhibited the greatest increase in LH after treatment. There was no effect of treatment, interval from onset of estrus to treatment or treatment by interval interaction on duration of the estrous cycle, on concentrations of progesterone from Days 1 through 14 posttreatment, or on concentrations of progesterone prior to subsequent estrus (Day -10 through 0, posttreatment estrus). In summary, FA administered to beef cattle within 12 h after onset of estrus effectively increased peripheral plasma concentration of LH, but this increase had no effect on subsequent luteal function as measured by duration of the estrous cycle or concentrations of plasma progesterone. In Study 2, 86 parous beef cows were bred artificially to one of two bulls following natural or prostaglandin F(2)alpha induced estrus. Cows received either no treatment or 50 or 100 mug FA at the time of AI. There was no effect of treatment, breed, parity, technician, service sire or interactions on conception rate (mean = 76.7%). Although not significant, the numerical pattern of conception rate among experimental groups (control = 71.4%, 50 mug FA = 76.7%, 100 mug FA = 82.1%) supports further investigation of this GnRH agonist with larger numbers of cattle.

Journal Article↗
PubMed1988

Ovine uterine morphogenesis: effects of age and progestin administration and withdrawal on neonatal endometrial development and DNA synthesis.

To determine effects of age and administration and withdrawal of a synthetic progestin (P) on endometrial development and DNA synthesis, ewe lambs were ovariectomized on d 0 (birth) and assigned to one of four groups (n = three/group) that provided (by means of hemihysterectomy) the following uterine tissue types: 1) d 0 control, 2) d 13 control, 3) d 26 control, 4) d 13 after 13 d exposure to P (13P) and 5) d 26 after P exposure from d 0 to 13 (26P). Uterine tissues were processed for histology or explanted with [methyl-3 H] thymidine for autoradiography. Labeling index (LI) was determined for stroma and epithelium in caruncular and intercaruncular endometrial areas and for lumenal and glandular epithelium in uteri with glands. Endometrial glands were absent on d 0, evident at d 13 and well developed by d 26. Day 0 LI was greater (P less than .05) in caruncular than in intercaruncular areas, and greater in stromal than in epithelial tissues. Relationships were reversed in d 13 endometrium (day X endometrial area, P less than .07). Caruncular stromal LI was greater on d 0 than later (P less than .02), whereas intercaruncular epithelial LI was greater after d 0 (P less than .05), but decreased from d 13 to 26 (P less than .05). Glandular epithelial LI was higher on d 13 than on d 26 (P less than .03). Administration of P inhibited endometrial gland development and suppressed d 13P intercaruncular LI (P less than .05). Withdrawal of P was followed by endometrial gland development and increased (P less than .01) intercaruncular epithelial LI in d 26P uteri. Ovary-independent initiation of endometrial gland development involves age- and region-specific alterations in DNA synthesis and could involve negative control.

Aging↗
PubMed1987

Models of the healthy worker effect in industrial cohorts.

The patterns of standardized mortality ratios (SMRs) with duration of follow-up and duration of service which are characteristic of the healthy worker effect in occupational cohort studies have been simulated using models of selection and survivor effects. The models support current theories about the population dynamics which underlie the selection effect but highlight inadequacies in our understanding of the survivor effect. Several possible models were tested and methods of generating appropriate data are discussed. It is important that the healthy worker effect should be better understood as it can present so large a problem in the interpretation of occupational risk estimates.

Adolescent↗
PubMed1987

Estrous synchronization and establishment of pregnancy in bovine embryo transfer recipients.

Characteristics of donors, embryos, recipients, and transfer procedures were examined for relationships with establishment of pregnancy. Data were from records of 1202 embryos transferred by the professional staff of a large embryo transfer company. Average pregnancy rate was 74.6%. Variables affecting establishment of pregnancy were service sire, embryo quality, stage of estrous cycle in recipient, quadratic effect of synchrony, and transfer quality. Because the direct or indirect effect of sire must be established at conception, these data demonstrate a latent effect of sire on pregnancy. One would expect the highest pregnancy rate among excellent quality embryos transferred with no delays or complications into recipients that had displayed estrus at the same time or prior to the donor yet were relatively early in their estrous cycles. There also was a tendency for pregnancy rate to decrease with advancing maturity of the embryo.

Animals↗
PubMed1987

Resection of the radial head for fracture of the radial head. Long-term follow-up of seventeen cases.

Seventeen patients who had a closed fracture of the radial head that was not associated with a dislocation of the elbow or another injury were evaluated eight to forty-six years after resection of the radial head. Few patients complained of even mild, intermittent pain. The ranges of motion of the wrist and elbow were nearly normal, but pronation and supination were decreased by an average of 7 and 15 degrees, respectively. Cybex testing showed losses of strength in pronation and supination of approximately 5 and 11 per cent, respectively. The ulnar variance became increasingly positive by an average of approximately two millimeters, and cubitus valgus increased an average of 9 degrees. These excellent results did not appear to deteriorate over time. In one patient a radio-ulnar synostosis developed.

Adolescent↗
PubMed1986

Relative durations of conditioned stimulus and intertrial interval in conditioned suppression.

The effects of the relative durations of the conditional stimulus and the intertrial interval on bar pressing during a conditioned-suppression procedure were examined as a function of two additional variables--type of operant baseline schedule and rate of shock presentation. In Experiment 1, response suppression was compared across components of a multiple fixed-ratio, random-ratio, fixed-interval, random-interval schedule, at relative conditioned-stimulus/intertrial-interval durations of 1/1, 1/4, and 1/9. In Experiment 2, relative conditioned-stimulus/intertrial-interval duration (1/5, 3/3, or 5/1) was manipulated across groups, while shock frequency (2, 6, or 10 shocks/hr) was manipulated within groups. In both experiments, suppression during the signal was virtually complete at all relative durations. Responding was also suppressed during the intertrial interval, but that suppression varied as a function of experimental manipulations. In Experiment 1, intertrial-interval response rates were higher when relative signal duration was 1/9 than when it was 1/1, although both relative signal duration and shock frequency, which covaried, could have contributed to the difference. In Experiment 2, the patterning of response rates between successive shocks was affected by relative duration, absolute rates during the intertrial interval varied as a function of shock frequency, and differences between suppression during the signal and suppression during the intertrial interval were affected by both relative duration and shock frequency. The data support an analysis based upon relationships between shock-correlated and intertrial-interval stimuli and, as assessed by the relative-delay-to-reinforcement metric, are comparable to results that have been reported from experiments using similar manipulations under the autoshaping paradigm.

Animals↗
PubMed1986

Marital distance and its geographical orientation in England and Wales, 1979.

"A representative sample of just over one thousand marriages solemnized in England and Wales in 1979 is used to analyse the distribution of the distances between the partners' addresses at marriage....according to various social and demographic variables also derived from the same source. Comparison with other surveys suggests that marriages in which both partners give the same address are likely to be those of couples who cohabit before marriage. Partners who work in unskilled manual occupations, or who marry with a civil ceremony, or who have been married before, appear more likely than the average to cohabit. Of the marriages where different addresses are given, about one-half bring together partners living within 5 km of each other." It is found that "there is a strong relationship between high social class and increased marital distance, and also between greater marital distance and older ages up to about age 40. Longer-range marriages show clear evidence of geographical orientation, the effect being more pronounced at longer distances. This is attributed to variations in population density over the country and geographical constraints on settlement patterns."

Age Factors↗