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Biomedical subjects

D C Willis

Publications and source records attributed to D C Willis.

10 recordsLinked to original sources
PubMed1995

Physiological and nutritional responses of steers infested with varying densities of Amblyomma americanum (Acari: Ixodidae).

The effects of varying densities of lone star tick, Amblyomma americanum (L.), on measured physiological parameters of beef cattle in a controlled environment was determined. Steers were infested with either 0, 20, 60, or 120 pairs of adult ticks. Heart rate, respiration, rectal temperature, fecal and urine excretions, and water and feed consumption were monitored daily. Blood samples were taken every 3rd d to measure cortisol, total proteins, urea nitrogen, and glucose levels. Hematocrits were also taken at each blood sampling. Results showed that A. americanum evoked elevated heart rates. The other measured physiological and nutritional responses of parasitized steers were similar to the control steers. These results suggest that tick densities were too low to cause physiological stress under the conditions used in this study. The methodology precluded detection of the parameters measured. A. americanum does not affect the parameters measured, or that fluctuating environmental parameters and varying host nutritional states may play major roles in modulating the effect of A. americanum infestations on cattle in nature.

Animal Nutritional Physiological Phenomena↗
PubMed1993

Vaginal birth after cesarean section. Acceptance and outcome at a rural hospital.

A retrospective review of all pregnant women with a history of cesarean section was conducted at an isolated military hospital. During the two-year period 1988-1989, 62 patients were initially considered eligible for attempting vaginal birth after cesarean section (VBAC). Seventy-nine percent (49/62) of the patients initially requested a trial of labor, and 14 of them ultimately did not meet American College of Obstetricians and Gynecologists criteria. Three patients reversed their decision late in pregnancy. Eighty-eight percent (28/32) of those undergoing a trial of labor delivered vaginally. The three patients with more than one prior cesarean section all delivered vaginally. The four failures occurred in patients who had a history of well-documented cephalopelvic disproportion. Perinatal morbidity consisted of intrauterine fetal demise prior to the onset of labor at 40 weeks' gestation. Maternal morbidity included postcesarean endometritis (n = 1) and vaginal sidewall laceration (n = 1). These results indicate that in a rural hospital VBAC was well accepted by patients and was safe; however, further study is required.

Decision Making↗
PubMed1990

The nonstress test. Criteria for the duration of fetal heart rate acceleration.

Although the most common definition of a reactive nonstress test is an acceleration in the fetal heart rate of 15 beats per minute (bpm) for 15 seconds, some investigators require that the fetal heart rate acceleration be maintained at 15 bpm above the baseline for the entire 15 seconds (long criterion), and others require simply that the acceleration be 15 seconds from the beginning until the return to the baseline (short criterion). In 1,241 nonstress tests (NSTs) there was a statistically significant difference in the number of reactive tests between the short and long criteria (1,108 [89%] vs. 985 [79%], P less than .001). This difference in percentage of reactivity may be important when comparing studies performed by various investigators. In comparing cesarean section deliveries for fetal distress we were unable to find a difference in the ability to predict a poor outcome between use of the short and long criteria. However, a type II error is possible since the number of poor outcomes was small. We now use the short criterion for NST interpretation.

Female↗
PubMed1988

Pregnancy in bulimic women.

Four primiparous bulimic women were interviewed. Pregnancy outcome was not affected adversely by bulimia. Gestational age ranged from 37-41 weeks, and average infant birth weight was 3121 g. Maternal weight gain averaged 40 lb. Bulimic behaviors decreased during pregnancy, but returned to prepregnant levels after delivery in three of the four women.

Birth Weight↗
PubMed1987

Cardiac output response to prostaglandin E2-induced abortion in the second trimester.

Maternal cardiac output changes were evaluated in 10 patients undergoing second-trimester abortion induced by prostaglandin E2 suppositories. The peak cardiac output increased by an average of 64.5% above preinduction values. This is similar to the percent increase described during oxytocin-induced labor at term. Inasmuch as resting cardiac output tends to be higher in midpregnancy than at term, absolute values during prostaglandin E2 induction were higher than those observed in laboring term patients.

Abortifacient Agents↗
PubMed1986

The rapid inhibition of urokinase by plasma from pregnant women at risk for abruptio placenta.

Rapid inhibition of urokinase in plasma obtained from women in the third trimester of pregnancy was assessed by the addition of 75 IU urokinase per ml plasma, and measurement of residual urokinase activity with PyroGlu-Gly-Arg-pNA after 5 minutes incubation at 37 degrees C. The urokinase inhibitory capacity was markedly increased for the pregnant women compared to non-pregnant controls. Alpha 1-antitrypsin, alpha 2-macroglobulin and alpha 2-antiplasmin did not account for the activity. Inhibition was higher for women with multiple gestations or macrosomia (n = 11) compared to normal pregnant women (n = 35) suggesting that the placenta contributes significantly to the measured activity. Inhibition was lower for women with hypertension (n = 33) compared to the normal pregnant women. Although the etiology for this difference is unclear, the decreased inhibitory activity may contribute to the increased risk for placental abruption that is observed for this group of women.

Abruptio Placentae↗
PubMed1983

Pregnancy in women with pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is characterized by degeneration of elastic tissue. Clinically, its effects are most readily noted in the skin, retina, blood vessels, and myocardium. Several hundred patients with this condition, signs and symptoms of which usually appear during the early portion of the reproductive years, have been reported. Fertility is unaffected. Despite this, only five articles describing the outcome of pregnancies in seven women with PXE have been recorded, none in the obstetric literature. This is particularly odd considering that five of the seven women suffered serious gastrointestinal hemorrhage during one or more of their pregnancies. One woman suffered congestive heart failure and cardiac arrhythmia during pregnancy, and a fatal attack of cardiac arrhythmia 2 months postpartum. The five articles are reviewed, basic information regarding PXE is given, a case history is recorded, and the possibility that pregnancy favors the development of these complications in patients with PXE is discussed.

Adult↗
PubMed1976

Birth sequence in mice.

Succession of deliveries at parturition was determined in mice following a marker injection in utero. The data failed to refute the hypothesis of a random birth order, as delivery from either uterine horn was found to be unpredictable. In addition, significantly more females delivered the first pup from the right uterine horn, supporting the concept of a "physiological dominance" for the right side of the mouse reproductive tract.

Animals↗
PubMedDate not supplied

Purchase of social services: another look.

Purchase of social services is an integral part of many social service delivery systems. Its advent was heralded by some as the fiscal salvation of hard-pressed social service agencies. This article reviews the problems of purchase of social services. It then discusses some of the literature and the research on the subject, including the author's own study in Utah, that are directly concerned with the variables of cost and quality. The author adds recommendations based on the findings presented.

Evaluation Studies as Topic↗