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Biomedical subjects

W Rayburn

Publications and source records attributed to W Rayburn.

35 records · Page 2Linked to original sources
PubMed1986

Acetaminophen pharmacokinetics: comparison between pregnant and nonpregnant women.

Acetaminophen is the most commonly taken drug during pregnancy, but knowledge about its absorption and disposition is lacking. Six healthy women volunteered to ingest a standard 1000 mg dose at 36 weeks' gestation and 6 weeks post partum. Mean maternal serum concentrations of acetaminophen were consistently less than but not significantly different from the postpartum values. The mean half-life of acetaminophen during pregnancy (3.7 hours) was not significantly different from the nonpregnant value (3.1 hours). The maximum plasma concentration occurred at 0.8 hours and was 20.8 +/- 6.9 micrograms/ml during pregnancy and 23.7 +/- 6.0 micrograms/ml in the nonpregnant state. The absorption, metabolism, and renal clearance of acetaminophen were unchanged. The decrease in the mean area under the curve during pregnancy may be explained by the increase in volume of distribution of acetaminophen. Potentially hepatotoxic metabolites were not measurable in the maternal serum. We conclude that the absorption and disposition of acetaminophen, when used in a standard oral dose, are not affected by pregnancy.

Acetaminophen↗
PubMed1986

Severe hypoglycemia during pregnancy: its frequency and predisposing factors in diabetic women.

Severe hypoglycemic episodes, as defined as altered consciousness to the extent that self treatment is impossible, were sought prospectively in pregnant diabetic women. One or more episodes were found in none of 21 gestational onset, insulin-requiring women during their 28 pregnancies but were present in 19 (33%) of the 57 already insulin dependent (Type 1) women during 26 (36%) of their 72 pregnancies. The most common predisposing factors included strict glucose control, anorexia, early morning hours (1200-0900), lack of an adrenergic response and time shortly before the next anticipated meal.

Adult↗
PubMed1986

Parenteral nutrition in obstetrics and gynecology.

Parenteral nutrition is required to maintain and restore an anabolic state when oral or enteral routes are not feasible. Despite 16 years of parenteral nutrition availability, reports about parenteral therapy in gynecologic patients or during pregnancy have not been published until relatively recently. Most information is anecdotal but suggests that this mode of therapy is safe, effective, and occasionally life-saving. Parenteral nutrition is used most commonly in women with gynecologic malignancies who are unable to obtain adequate nourishment either during or after surgery, radiation, or chemotherapy. Parenteral alimentation during pregnancy has been used mostly to provide adequate nutrition for those who suffer from prolonged hyperemesis or when there is difficulty in absorption of adequate nutrients. The proper selection and administration of dextrose, fat, protein, vitamins, trace elements, and electrolytes for pregnant women has been associated with apparent favorable perinatal outcomes. Preterm deliveries and intrauterine fetal growth retardation are relatively common and relate to the preexisting or a coexisting medical or obstetric complication. Nutritional assessment before therapy should include a detailed diet history and establishment of baseline clinical and laboratory parameters. Oral or enteral feedings should be attempted beforehand if possible to conserve high costs and potential complications. Parenteral requirements are extrapolated from recommended daily allowances for oral intake, allowing for adjustments in variable absorption. Standardized formulations and fat emulsions are available at pharmacies in many hospitals, making ordering of complex solutions easier, more efficient, and cost effective. Metabolic and septic complications occur infrequently with close monitoring. Few women require intravenous therapy for very long, and home parenteral nutrition is rarely necessary.

Adolescent↗
PubMed1986

Intravenous ritodrine therapy: a comparison between twin and singleton gestations.

The purpose of this study was to determine whether or not guidelines for intravenous ritodrine therapy for singleton pregnancies in premature labor also apply for twin gestations. Between January 1982 and March 1985, 43 (18%) of 239 women admitted in premature labor had twin fetuses. Intravenous ritodrine therapy was used for four or more hours in 23 of these pregnancies. Compared with a matched group of 23 singleton pregnancies, increases in maternal and fetal heart rates and decreases in maternal diastolic blood pressures were not significantly different. Undesired cardiovascular effects were no more common and usually occurred during the initial infusion period when the dose was increased most rapidly. The averaged doses, duration of therapy, and delays in delivery were also similar between the twin and singleton groups.

Adult↗
PubMed1985

Changes in insulin therapy during pregnancy.

Care of the diabetic pregnant woman requires a proper understanding of anticipated changes in insulin therapy as a guide for establishing and maintaining strict glucose control. Changes in daily insulin doses were reviewed for 58 pregnancies of 50 insulin-dependent women who were followed for 26 +/- 3 weeks (mean +/- 1 SD) before delivery. By late gestation, insulin was administered on two or three occasions each day using a combination of regular--and intermediate--acting preparations in 55 (95%) pregnancies. Regardless of the metabolic control and duration of diabetes, averaged daily insulin requirements increased twofold from earlier in pregnancy. Following initial hospitalization, insulin requirements often decreased before increasing almost linearly between 2 and 9 months gestation. Fluctuations in insulin requirements were greatest during the last trimester. Insulin demand dropped precipitously after delivery and was two-thirds the averaged prepregnancy insulin dose or one-third the dose at 9 months gestation by the third postpartum day. The total average insulin dose was the same as that before pregnancy by the end of the first postpartum week. Explanations for these changes in prescribing insulin are described.

Diabetes Mellitus, Type 1↗
PubMed1985

Comparison of moxalactam and cefazolin as prophylactic antibiotics during cesarean section.

Prophylactic antibiotics have been shown to be effective in decreasing the incidence of febrile morbidity associated with cesarean section after labor. However, the relative effectiveness of different single antibiotics has been studied infrequently, and these investigations have been limited by small patient samples. Several new, broad-spectrum antibiotics are now available, and any further benefit from more traditional antibiotics for surgical prophylaxis remains untested. A randomized prospective double-blind therapeutic trial was therefore undertaken to compare the value of a first-generation cephalosporin (cefazolin) with a new third-generation cephalosporin (moxalactam). Between July 1981 and June 1983, 254 qualifying women who underwent primary cesarean section after labor were randomly chosen for either of the two treatment groups. Although not statistically significant, the rates of febrile morbidity, wound infection, and endometritis were less for those treated with cefazolin (4.0, 3.2, and 0.8%, respectively) than for those treated with moxalactam (9.2, 7.7, and 1.6%, respectively). No serious adverse effects were apparent in the mother and newborn infant from short-term exposure to either drug. Although the newer, more expensive, and broader-spectrum cephalosporin, moxalactam, was associated with a low postoperative febrile morbidity rate and short postpartum hospitalization, it was no more beneficial than cefazolin.

Anti-Bacterial Agents↗
PubMed1985

The stillborn fetus: placental histologic examination in determining a cause.

This investigation was undertaken to determine whether or not histologic examination of the placenta contributed to a better understanding of the cause for an intrauterine fetal death. The placentas of stillborn fetuses delivered after the 20th gestational week were examined during a 4.5-year period (January 1979 to June 1983). Adequate information about the clinical history, autopsy examination, and placental histological examination was available in 89 cases. Delivery was usually within the first week after the fetal death. Significant histologic aberrations in the placenta were found in 87 (98%) cases. The most frequent abnormalities were those of vascular insufficiency, hemorrhagic endovasculitis, retroplacental hematomata, acute chorioamnionitis with fetal involvement, and erythroblastosis/hydrops. Histologic abnormalities were supportive of prior impressions in 67 (77%) cases, contradictory to prior impressions in ten (11%) cases, or the sole contributors in explaining the cause of death in ten (11%) cases. Routine histologic examination of the placenta after a recent fetal death provides helpful information in counseling the parents and in planning any future childbearing.

Chorioamnionitis↗
PubMed1984

Drug overdose during pregnancy: an overview from a metropolitan poison control center.

Suicide attempts during pregnancy usually present as intentional drug overdoses after interpersonal conflicts. During a recent four-year period, 119 (0.07%) of all 179,893 telephone inquiries at a metropolitan poison control center involved drug overdoses by 111 pregnant women. This was usually the first such attempt and telephone notification occurred primarily within the first hour. The ingested substance was known in 109 (98%) cases and consisted mostly of an excess of a single drug. The 50 different types of over-the-counter and prescription medications consisted primarily of analgesics (most notably acetaminophen), vitamins or iron, sedatives, antibiotics, and antihistamines or decongestants. No maternal deaths were reported. Signs or symptoms were nonexistent or mild in 61 (55%) women, and major or life-threatening in 50 (45%) women. Compliance with recommendations given by telephone and referral to the primary physician or emergency room was good, especially when major symptoms or life-threatening illnesses were apparent. Close emotional support and a search for depression during pregnancy and the postpartum period are recommended.

Adolescent↗
PubMed1984

Major burns during pregnancy: effects on fetal well-being.

The authors reviewed the fetal outcomes for 30 pregnant patients who required hospitalization for burns that involved 11 to 97% of the total body area. A positive relationship was found between the percentage of maternal total body burn and maternal mortality, fetal mortality, and premature delivery. Premature delivery and/or fetal mortality occurred primarily within the first five days and followed maternal complications of hypovolemic shock, sepsis, or respiratory insufficiency. In the eight cases in which maternal injury became lethal (20 to 97% total body burn), all fetuses were born spontaneously before maternal death, but seven were stillborn. After overcoming the immediate postburn period, a healthy-appearing term-size infant was likely to be born while the mother continued to receive intensive therapy. The ideal treatment to protect the fetus has not yet been determined.

Abnormalities, Multiple↗
PubMed1982

Prenatal counseling: a statewide telephone service.

The University of Michigan has provided a statewide prenatal counseling service for obstetricians and pregnant patients since 1974. Using a toll-free telephone hot line, 5204 inquiries have been made, relating to genetic conditions, exposure to potential teratogens, and obstetric or medical complications during early pregnancy. Up-to-date and accurate information has been supplied by a team of nurses and physicians with backgrounds in genetics or maternal-fetal medicine. Calls were taken by perinatal nurse counselors and referred to the appropriate medical specialist. The number of inquiries has increased from 3 per week in 1974 to 30 per week in 1981. Genetic amniocenteses, performed in response to 46% of all inquiries, provided financial support for the project. The authors consider the statewide use of this self-supported prenatal counseling service to be encouraging and recommend that this format be used at other institutions.

Adult↗
PubMed1980

An alternative to antepartum fetal heart rate testing.

The high-risk pregnancies of 203 patients were prospectively studied to test the hypothesis that the maternal perception of fetal movement is as useful as antepartum fetal heart rate testing (AFHRT) in assessing fetal welfare. Evidence for an active fetus (186 cases, 92%) was usually followed by a normal AFHRT result (320/330 results, 97%). Furthermore, a favorable perinatal outcome was equally predicted by an active fetus (168/186 cases, 90%) and a normal AFHRT result (173/190 cases, 91%). Evidence for an inactive fetus was less sensitive but not significantly different from an abnormal AFHRT in predicting an unfavorable perinatal outcome (10/17 cases versus 11/13 cases, p > 0.05). However, an abnormal AFHRT result coincident with fetal inactivity was highly predictive of an unfavorable neonatal outcome in nine of 10 cases. In conclusion, the data reveal that a record of fetal activity by the compliant patient is a reliable alternative to AFHRT for the initial screening of fetal well-being.

Female↗
PubMed1980

Nonstress testing and perinatal outcome.

The clinical value of nonstress testing (NST) in assessing fetal well-being is controversial. This study reviews the monitored tracings and subsequent perinatal outcome of 561 high-risk clinic patients who had undergone NST within one week prior to delivery. Two or more adequate accelerations of the fetal heart rate baseline with sufficient fetal activity over a 20-minute period were associated with a low risk of fetal jeopardy and were classified as a reactive test result. The corrected perinatal mortality of patients with reactive NSTs (1/509) was comparable to that of patients with no apparent antepartum complications (6/1,408) and was significantly lower (p less than 0.05) than those of high-risk patients with either nonreactive NSTs (2/22) or no testing (20/1,000). The incidence of subsequent perinatal jeopardy was significantly lower (p less than 0.001) among those high-risk pregnancies with recent reactive NST results (4%) than in those with recent nonreactive NST results (36%) and those without recent testing (13%). Perinatal morbidity among those pregnancies with recent reactive NSTs usually arose in the intrapartum period, and no reason to explain this jeopardy predominated. A reactive NST can be safely repeated in seven days, regardless of the adequately treated maternal risk factor. The only stillbirth following a reactive NST (1/509) probably arose from a cord accident.

Adult↗
PubMed1979

Corticosteroid-binding globulin and estrogens in maternal and cord blood.

Corticosteroid-binding globulin (CBG) is produced by the liver in small concentrations and binds steroids with high affinity. Its concentration in the blood is sensitive to endogenous or exogenous estrogens in a dose-response manner and serves as a biological assay for estrogens. CBG concentrations were measured in sera collected from maternal and umbilical vein blood during labor and delivery and at elective cesarean section and correlated with endogenous estradiol and estriol concentrations. CBG and estradiol concentrations of maternal blood were significantly exceeded those of maternal serum. A highly significant increase in cord blood estriol concentration was found following vaginal delivery compared to elective cesarean section, indicating an increase in adrenal activity due to the stress of labor. CBG levels correlated directly with maternal estradiol but not estriol cencentrations. Cord blood CBG concentration varied little despite a wide range of estrogen concentrations. The physiologic significance of CBG concentrations in maternal and fetal blood is discussed.

Cesarean Section↗
PubMed1979

Therapeutic implications of patterns of recurrence in cancer of the uterine cervix.

Five hundred twenty-six patients with invasive cervical cancer, treated at the University of Kentucky from 1964 to 1976, were followed 2--12 years after therapy. One hundred and sixty patients (31%) developed tumor recurrence. Recurrent cancer was noted with 1 year after therapy in 58% of patients and within 2 years of treatment in 76% of patients. Only 6% of patients with recurrent cervical cancer survived 3 or more years. Stage of disease, cell type, lesion size, and the presence of lymph vascular space invasion by tumor cells were all shown to be prognostically significant. The addition of extrafascial hysterectomy to radiation therapy significantly decreased the incidence of recurrence in stage IB cervical tumors 5 cm or more in diameter. Analysis of this data suggests that radical hysterectomy and pelvic lymphadenectomy is as effective as irradiation only in the treatment of large cell squamous carcinomas 2 cm or less in diameter.

Adenocarcinoma↗
PubMedDate not supplied

Some factors affecting phencyclidine biotransformation by human liver and placenta.

Samples of human liver and placenta microsomes were analyzed for their in vitro hydroxylation capabilities using phencyclidine, [PCP, 1-(1-phenylcyclohexyl)piperidine] as substrate. Microsomes were prepared from full-term placentas (cesarean deliveries under epidural anesthesia) and from histologically normal liver specimens (staging laparotomies for Hodgkin's disease). Three different hydroxylated PCP metabolites were assayed including 1-(1-phenyl-3-hydroxycyclohexyl)piperidine (3-OH-cyclo-PCP), 1-(1-phenyl-4-hydroxycyclohexyl)piperidine (3-OH-cyclo-PCP), 1-(1-phenyl-4-hydroxycyclohexyl)piperidine (4-OH-cyclo-PCP), and 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (4-OH-pip-PCP). The mean amounts of in vitro microsomal hydroxylation of PCP at the three different positions of the PCP ring varied considerably between individual samples of both liver and placenta. The placenta hydroxylated PCP but not as effectively as liver. Evidence for independent hydroxylation of PCP to 3-OH-cyclo-PCP was comparable to 4-OH-cyclo-PCP and 4-OH-pip-PCP. The formation of 3-OH-cyclo-PCP by the liver was enhanced in tobacco smokers. The formation of 4-OH-cyclo-PCP by the liver was negatively correlated with the stage of Hodgkin's disease even though the liver was free of disease in 11 of 12 subjects.

Anesthesia↗