Biomedical subjects

M Varner

Publications and source records attributed to M Varner.

17 recordsLinked to original sources

PubMed2001

Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection.

BACKGROUND: Infection with Trichomonas vaginalis during pregnancy has been associated with preterm delivery. It is uncertain whether treatment of asymptomatic trichomoniasis in pregnant women reduces the occurrence of preterm delivery. METHODS: We screened pregnant women for trichomoniasis by culture of vaginal secretions. We randomly assigned 617 women with asymptomatic trichomoniasis who were 16 to 23 weeks pregnant to receive two 2-g doses of metronidazole (320 women) or placebo (297 women) 48 hours apart. We treated women again with the same two-dose regimen at 24 to 29 weeks of gestation. The primary outcome was delivery before 37 weeks of gestation. RESULTS: Between randomization and follow-up, trichomoniasis resolved in 249 of 269 women for whom follow-up cultures were available in the metronidazole group (92.6 percent) and 92 of 260 women with follow-up cultures in the placebo group (35.4 percent). Data on the time and characteristics of delivery were available for 315 women in the metronidazole group and 289 women in the placebo group. Delivery occurred before 37 weeks of gestation in 60 women in the metronidazole group (19.0 percent) and 31 women in the placebo group (10.7 percent) (relative risk, 1.8; 95 percent confidence interval, 1.2 to 2.7; P=0.004). The difference was attributable primarily to an increase in preterm delivery resulting from spontaneous preterm labor (10.2 percent vs. 3.5 percent; relative risk, 3.0; 95 percent confidence interval, 1.5 to 5.9). CONCLUSIONS: Treatment of pregnant women with asymptomatic trichomoniasis does not prevent preterm delivery. Routine screening and treatment of asymptomatic pregnant women for this condition cannot be recommended.

Adult↗

PubMed2000

Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units.

BACKGROUND: Bacterial vaginosis has been associated with preterm birth. In clinical trials, the treatment of bacterial vaginosis in pregnant women who previously had a preterm delivery reduced the risk of recurrence. METHODS: To determine whether treating women in a general obstetrical population who have asymptomatic bacterial vaginosis (as diagnosed on the basis of vaginal Gram's staining and pH) prevents preterm delivery, we randomly assigned 1953 women who were 16 to less than 24 weeks pregnant to receive two 2-g doses of metronidazole or placebo. The diagnostic studies were repeated and a second treatment was administered to all the women at 24 to less than 30 weeks' gestation. The primary outcome was the rate of delivery before 37 weeks' gestation. RESULTS: Bacterial vaginosis resolved in 657 of 845 women who had follow-up Gram's staining in the metronidazole group (77.8 percent) and 321 of 859 women in the placebo group (37.4 percent). Data on the time and characteristics of delivery were available for 953 women in the metronidazole group and 966 in the placebo group. Preterm delivery occurred in 116 women in the metronidazole group (12.2 percent) and 121 women in the placebo group (12.5 percent) (relative risk, 1.0; 95 percent confidence interval, 0.8 to 1.2). Treatment did not prevent preterm deliveries that resulted from spontaneous labor (5.1 percent in the metronidazole group vs. 5.7 percent in the placebo group) or spontaneous rupture of the membranes (4.2 percent vs. 3.7 percent), nor did it prevent delivery before 32 weeks (2.3 percent vs. 2.7 percent). Treatment with metronidazole did not reduce the occurrence of preterm labor, intraamniotic or postpartum infections, neonatal sepsis, or admission of the infant to the neonatal intensive care unit. CONCLUSIONS: The treatment of asymptomatic bacterial vaginosis in pregnant women does not reduce the occurrence of preterm delivery or other adverse perinatal outcomes.

Adult↗

PubMed2000

An oxytocin receptor antagonist (atosiban) in the treatment of preterm labor: a randomized, double-blind, placebo-controlled trial with tocolytic rescue.

OBJECTIVES: This study was designed to evaluate the efficacy and safety of the oxytocin receptor antagonist atosiban in the treatment of preterm labor. STUDY DESIGN: A multicenter, double-blind, placebo-controlled trial with tocolytic rescue was designed. Five hundred thirty-one patients were randomized to receive, and 501 received, either intravenous atosiban (n = 246) or placebo (n = 255), followed by subcutaneous maintenance with the assigned agent. Standard tocolytics as rescue tocolysis were permitted after 1 hour of either placebo or atosiban if preterm labor continued. The primary end point was the time from the start of study drug to delivery or therapeutic failure. Secondary end points were the proportion of patients who remained undelivered and did not receive an alternate tocolytic at 24 hours, 48 hours, and 7 days. RESULTS: No significant difference was found in the time from start of treatment to delivery or therapeutic failure between atosiban and placebo (median, 25.6 days vs 21.0 days, respectively; P =.6). The percentages of patients remaining undelivered and not requiring an alternate tocolytic at 24 hours, 48 hours, and 7 days were significantly higher in the atosiban group than in the control group (all P < or =.008). A significant treatment-by-gestational age interaction existed for the 48-hour and 7-day end points. Atosiban was consistently superior to placebo at a gestational age of > or =28 weeks. Fourteen atosiban-treated patients and 5 placebo-treated patients were randomized at <24 weeks; the incidence of fetal-infant deaths was higher for the atosiban group at <24 weeks. Maternal-fetal adverse events were similar except for injection-site reactions, which occurred more often with atosiban. CONCLUSIONS: In this trial the treatment of patients in preterm labor with atosiban resulted in prolongation of pregnancy for up to 7 days for those at a gestational age > or =28 weeks, and this occurred with a low rate of maternal-fetal adverse effects. In addition, at a gestational age > or =28 weeks, the infant morbidity and mortality of atosiban-initiated standard care were similar to those with placebo-initiated standard care. Given that all patients in this study were eligible for tocolysis and that, in practice, nearly all patients who are eligible for a tocolytic receive one, the benefit of using atosiban is the placebo-like maternal-fetal side effect profile. These observations support the use of this oxytocin receptor antagonist in the treatment of patients in preterm labor with intact membranes. Efficacy and infant outcome data at <28 weeks are inconclusive.

Double-Blind Method↗

PubMed2000

Evaluation of a noninvasive transcranial Doppler and blood pressure-based method for the assessment of cerebral perfusion pressure in pregnant women.

OBJECTIVE: We have developed a Doppler method for the estimation of cerebral perfusion pressure (CPP) using noninvasive techniques. Our objective was to evaluate our new method in pregnant women. METHODS AND MATERIALS: Laboring women with a lumbar epidural in situ had transcranial Doppler interrogation of the maternal middle cerebral artery (MCA) to measure systolic, diastolic, and mean velocities. A pressure transducer was connected to the epidural catheter and pressure was recorded. Systolic (SBP), diastolic (DBP), and mean (MAP) blood pressure were taken with a Dinamap monitor. Doppler estimated CPP (mm Hg) = [V(mean)/(V(mean) - V(diastolic)](MAP - DBP) and directly measured CPP = MAP - Epidural pressure data were plotted on a Bland-Altman graph with limits of agreement. The mean difference (the mean of the sum of both positive and negative differences) and absolute difference (the mean of the sum of the absolute differences) were calculated. In addition, linear and polynomial regression analyses were performed. RESULTS: Twenty laboring women were studied. All had normal pregnancies. The mean maternal age was 28 +/- 7 years and the mean gestational age was 39 +/- 2 weeks. The mean maternal MAP was 77 +/- 12 mm Hg. The Bland-Altman plot showed a mean difference of 2.2 mm Hg at a mean CPP of 65 +/- 12 mm Hg; with a standard deviation of 4.8 mm Hg, the absolute difference was 3.9 +/- 3.0 mm Hg at a mean CPP of 65 +/- 12 mm Hg. The regression analysis showed an r = 0.92, r(2) = 0.86, and p < 0.0001. CONCLUSIONS: Our formula allows the estimation of CPP using a simple calculation and noninvasively acquired data. This method may be of use for frequent, easy, and accurate CPP and intracranial pressure estimation and may, as such, have significant research and clinical applications.

Adult↗

PubMed2000

The impact of somatotropin, milking frequency, and photoperiod on dairy farm nutrient flows.

Three technologies that increase milk production per cow and that are available to dairy producers are bovine somatotropin, three times daily milking, and extended daily photoperiod. Dairy herds fed according to National Research Council requirements were simulated to predict the impact of these technologies on N losses to manure and to water resources. Because Dairy Herd Improvement Association total lactation records (n = 93,080) revealed a positive linear relationship between 305-d milk production and calving interval, calving intervals were predicted to increase with the use of technologies and to result in a change in the ratio of lactating cows to growing heifers in a herd. Compared with a herd using no technologies, the use of bovine somatotropin, three times daily milking, or extended photoperiod were predicted to reduce herd N excretion per unit of milk by 7.8, 7.0, and 3.6%, respectively. When the use of all three technologies was simulated, N losses to manure were decreased by 15.7% when assuming calving interval increases from the technologies or 15.4% without accounting for calving interval increases. Reductions in feed N requirements and manure N losses with these three technologies were predicted to reduce environmental N loading by up to 16%.

Animal Nutritional Physiological Phenomena↗

PubMed1999

Preeclampsia may cause both overperfusion and underperfusion of the brain: a cerebral perfusion based model.

BACKGROUND: The hypothesis was that low cerebral perfusion pressure is more common in women with mild preeclampsia as compared to those with severe preeclampsia, while high cerebral perfusion pressure is more common in women with severe preeclampsia than in women with mild preeclampsia. DESIGN: Prospective, observational study. SETTING: University teaching hospitals. METHODS: Transcranial Doppler ultrasound was used to measure the blood velocity in the middle cerebral arteries of 54 patients with mild preeclampsia and 44 patients with severe preeclampsia. Blood pressure was measured simultaneously. Cerebral perfusion pressure was calculated and plotted on the same axes as data from 63 normal pregnant women. Data outside of the 95% prediction limits were regarded as abnormal. All studies were prior to labor, and before volume expansion or treatment. ANALYSIS: Student's t-test, Mann Whitney U test, and Fisher's exact test as appropriate with two-tailed p<0.05. MAIN OUTCOME MEASURE: The number of patients in each group with cerebral perfusion pressure values outside the normal 95% prediction limits. RESULTS: Almost the same number of women with mild (21/54=39%) and severe (15/44=34%) preeclampsia had measurements within the normal range (p=0.78). Mild preeclamptic women were more likely to have low (28/54=52%) rather than high cerebral perfusion pressure (p<0.001), while severe preeclamptics were more likely to have high cerebral perfusion pressure (26/44=59%) than low (p<0.001). CONCLUSIONS: In preeclampsia the brain can be normally perfused, underperfused and over-perfused. Although many women with mild preeclampsia will have underperfusion (52%), and a significant number of women with severe preeclampsia will have overperfusion (59%), many preeclamptic women have cerebral perfusion within the normal range.

Adult↗

PubMed1997

Fetal carriers of the factor V Leiden mutation are prone to miscarriage and placental infarction.

OBJECTIVES: The factor V Leiden mutation is the most common genetic predisposition to thrombosis. However, little is known concerning the reproductive outcome of mutation carriers or prenatal expressivity of this thrombogenic mutation. Our purpose was to examine whether this mutation presents phenotypically as miscarriage or idiopathic placental thrombosis. STUDY DESIGN: We performed two studies. First, a case-control comparison to determine whether fetal or maternal carriers of the factor V Leiden mutation are at risk for spontaneous miscarriage was performed, and, second, a cohort study evaluating placental infarction in fetuses carrying this mutation was performed. RESULTS: We found a twofold increase in the factor V Leiden carrier frequency in 12 of 139 (8.6%) abortuses compared with 17 of 403 (4.2%) unselected pregnant women seen in the labor and delivery suite and, even more remarkable, a tenfold increase in the fetal carrier frequency in 10 of 24 (42%) placentas with > 10% placental infarction compared with 7 of 372 (1.9%) placentas with < 10% placental infarction. CONCLUSIONS: These findings suggest a prenatal phenotype and effects of this mutation at the fetoplacental interface. If large prospective studies confirm these findings, then testing for this thrombogenic mutation should be considered in women and placental tissue from spontaneous abortuses and placentas with evidence of placental infarction. In addition to identifying individuals and families at risk for thrombosis, this information may help to improve our understanding of hemostasis and circulatory disturbances at the fetoplacental interface.

Abortion, Spontaneous↗

PubMed1997

A promoter mutation that increases transcription of the tumor necrosis factor-alpha gene is not associated with preterm delivery.

OBJECTIVE: Increased amniotic fluid concentrations of tumor necrosis factor-alpha are observed in women with preterm labor and subsequent preterm birth. We tested whether a mutation in the promoter region of tumor necrosis factor-alpha gene, TNF T2, which increases transcription of the gene, is more frequent in a preterm delivery cohort. STUDY DESIGN: Deoxyribonucleic acid was extracted from whole blood of 203 women and 44 fetuses delivered at < 37 weeks of estimated gestational age. The polymerase chain reaction was used to amplify the promoter region of the tumor necrosis factor-alpha gene. The resulting polymerase chain product was subjected to allele-specific enzymatic digestion with Nco I. Fragments were size fractionated on a 3% Metaphor agarose gel stained with ethidium bromide. Results were analyzed with use of a chi 2 contingency table. RESULTS: No statistically significant differences for either the TNF T1 or TNF T2 allele frequencies were found between women or fetuses delivered preterm compared with a control group or previously published allele frequencies. CONCLUSIONS: The frequency of this tumor necrosis factor-alpha promoter mutation, TNF T2, is not increased in either women or fetuses delivered at < 37 weeks' gestation. Basal levels of tumor necrosis factor-alpha are unlikely to affect a woman's risk of preterm delivery. Tumor necrosis factor-alpha variants should not be used as a predictive test for preterm delivery.

Adolescent↗

PubMed1996

Rapid detection of group B streptococcal colonization of the genital tract by a commercial optical immunoassay.

The performance of a commercial optical immunoassay (OIA) was compared at two institutions with that of routine agar and broth culture methods for the detection of group B streptococcal (GBS) colonization of the genital tract. The Strep B OIA (Bio Star, USA) was used to test 962 vaginal swabs from pregnant women for the presence of GBS antigen. The prevalence of GBS vaginal colonization in this population was 22.4%. The OIA results were compared with those of culture on trypticase soy agar with 5% sheep blood (TSA) and broth enhanced culture (Lim broth). Sensitivity and specificity values of the OIA method compared to TSA culture alone were 82.5% and 91.8%, respectively. The sensitivity of the OIA method was equivalent to that of TSA culture (62.4% vs. 64.4%; p > 0.5, chi 2 = 0.01) when the data were compared with broth culture. The extent of colonization affected the sensitivity of the OIA method: 100% of 4+, 94% of 3+, 96% of 2+, and 63% of 1+ TSA plates were detected by the OIA test. The commercial OIA method demonstrated sensitivity equivalent to that of TSA culture for the detection of GBS colonization. The OIA test offers two additional advantages over culture: reduced time required to obtain results (30 min vs. days) and the ability to detect GBS antigen in samples with compromised viability. The results of this study suggest that the Strep B OIA test can be a useful diagnostic tool in the management of early-onset GBS disease.

Antigens, Bacterial↗

PubMed1996

Value of fetal fibronectin as a predictor of preterm delivery for a low-risk population.

OBJECTIVE: We examined clinical value of cervical fetal fibronectin detection by a quantitative enzyme-linked immunosorbent assay as a predictor of preterm delivery in a population (n = 111) of middle-class pregnant women considered to be at low risk for preterm delivery. STUDY DESIGN: In this prospective study, fetal fibronectin samples from cervicovaginal secretions were obtained biweekly from 24 to 34 weeks' gestation. RESULTS: Twenty-two (20%) patients had at least one positive fetal fibronectin test result. Eleven women (10%) were delivered spontaneously at < 37 weeks; seven of these had at least one positive fetal fibronectin test result (positive predictive value = 31.8%, sensitivity = 63.6). An additional three women were delivered prematurely because of other obstetric indications, and all had negative fetal fibronectin test results. The remaining 15 patients with at least one positive fetal fibronectin test result were delivered at term (> or = 37 weeks). Of the seven women with positive fetal fibronectin results who were delivered prematurely, five were delivered within 2 weeks of obtaining a positive result. However, there were no obvious clinical discriminators between true-positive and false-positive fetal fibronectin results. Eighty-nine women tested negative, and 85 of these women were delivered at term (specificity = 82.0%). The negative predictive value of fetal fibronectin as a predictor of term delivery in this low-risk population is 96.6%, with odds ratio = 8.8 (95% confidence interval 1.9 to 40.3), relative risk = 6.9 (95% confidence interval 1.8 to 26.6), and Fisher Exact Test p = 0.007. CONCLUSIONS: Although negative biweekly fetal fibronectin determinations for prediction of preterm delivery in this low-risk obstetric population correlate well with the absence of preterm delivery, they are of limited clinical value for the prediction of preterm birth.

Adult↗

PubMed1995

Fixed yield responses to increased milking frequency.

Data from 19 literature reports that measured the effect of milking frequency on milk yield were summarized. When milking three times daily was compared with milking twice daily, the three times daily yield was 3.5 kg/d higher with a 95% confidence interval of 3.1 to 3.9 kg/d. Response of fat yield to increased milking frequency, from twice daily to three times daily, was 92 g/d, and the 95% confidence interval was 67 to 117 g/d. Linear regression analysis showed that no relationship existed between twice daily milk yield or fat yield and the amount of increase of milk yield or fat yield caused by increasing milking frequency to three times daily. This result implied that increased milking frequency from twice to three times daily resulted in a fixed increase of 3.5 kg/d of milk yield and 92 g/d of fat yield, regardless of the yield for cows milked twice daily. Responses of primiparous and multiparous cows were similar in magnitude for twice daily versus three times daily milking frequency, suggesting that the separate adjustment factors currently used for conversion of three times to twice daily equivalents for primiparous and multiparous cows may not be needed if adjustments are expressed on the basis of actual yield. The numbers of comparisons of once daily and four times daily milking frequency with twice daily milking were limited, but showed no relationship with milk yield, and the mean response was -6.2 and 4.9 kg/d, respectively. These data also support the concept of a fixed yield response to altered milking frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Postpartum hemorrhage.

Early PPH remains a significant cause of maternal morbidity and mortality. Many cases occur in women with antecedent risk factors and can thus be anticipated, promptly diagnosed, and promptly treated. Postpartum hemorrhage is most commonly due to uterine atony and often responds to medical treatments such as ecbolic medications, uterine massage or bimanual compression, and blood and fluid replacement. Appropriate laboratory studies should be obtained promptly. Women with significant bleeding should receive blood product transfusions. Patients who do not promptly respond to these conservative measures should be considered and counseled for operative procedures. Surgical intervention, either to repair lacerations, transiently reduce pelvic pulse pressure, or remove the uterus, can be life-saving.

Blood Transfusion↗

PubMed1989

Long-term tocolysis with intravenous magnesium sulfate.

Although the tocolytic effect of magnesium sulfate is well known, it has generally been used for this purpose for only brief periods. In this study, we administered intravenous magnesium sulfate tocolysis, either alone or in combination with other tocolytics, to 111 women as follows: 1) 60 (54%) received the drug for 3 or fewer days (short-term group); 2) 29 (26%) received the drug for 3-10 days (intermediate group); and 3) 22 (20%) received the drug for 10 days or longer (long-term group). Side effects (ileus and/or constipation, visual blurring, headache) were more common in the intermediate and long-term groups, but no life-threatening complications were seen. The drug was discontinued because of side effects in 7% of the patients in each group. We believe our data indicate that there need be no time limit and that magnesium sulfate tocolysis may be continued as clinically indicated.

Delivery, Obstetric↗

PubMed1986

Antenatal diagnosis and palliative treatment of nonimmune hydrops fetalis secondary to pulmonary extralobar sequestration.

The causes of nonimmune hydrops fetalis are multiple. Despite the fact that many of the affected fetuses are otherwise free of fatal abnormalities, many die in the neonatal period from pulmonary hypoplasia. The overall perinatal mortality is as high as 80%. Extralobar pulmonary sequestration is an abnormal and nonaerated mass of extra pulmonary-located lung tissue supplied by a systemic artery, and is a rare cause of nonimmune hydrops. In the only two published reports, the hydropic fetuses died at birth. Both the first antenatal diagnosis of this disorder and the first attempt at palliative in utero therapy are reported herein. Though the fetus ultimately delivered prematurely and succumbed, treatment was associated with both subjective improvements in fetal well-being and objective reversal of the hydrops.

Adult↗

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↗

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↗

PubMed1980

Acute fatty metamorphosis of pregnancy. A maternal mortality and literature review.

Acute fatty metamorphosis of pregnancy is a rare but very serious pregnancy complication with an extremely high fetal (85%) and maternal (75%) mortality rate. The abrupt onset of severe and persistent vomiting near term is followed by jaundice within several days. Symptoms progress rapidly, with coagulopathies, deterioration of mental status and renal failure common. Often the patients appear to have preeclampsia. Treatment rests on meticulous attention to metabolic management. The 61st histologically documented case is presented and the clinical and laboratory features of the disease discussed.

Acute Disease↗