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Biomedical subjects

H M Silver

Publications and source records attributed to H M Silver.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of vagal baroreflex function in nonpregnant women and in women with normal pregnancy, preeclampsia, or gestational hypertension.

OBJECTIVE: Our aim was to compare baroreflex function among nonpregnant women and among women with normal pregnancy, preeclampsia, or gestational hypertension. STUDY DESIGN: Baroreflex function was tested in 20 women with preeclampsia, in 20 age- and gestational age-matched normotensive gravid women, in 20 age-matched nonpregnant women, and in 20 nonmatched women with gestational hypertension. The baroreflex was measured by several modalities. RESULTS: Vagal baroreflex gain measured by cross-spectral analysis of parallel spontaneous heart rate and blood pressure changes is significantly decreased in normal pregnancy (15.8 +/- 7.2 vs 10.8 +/- 4.1 ms/mm Hg; P = 0.001), in comparison with vagal baroreflex gain in nonpregnant women. Baroreflex gain is further reduced in preeclamptic pregnancy (10.8 +/- 4.1 vs 7.2 +/- 2.6 ms/mm Hg; P = 0.003) and in gestational hypertension (10.8 +/- 4.1 vs 6.5 +/- 2.7 ms/mm Hg; P = 0.001), compared with that in normal pregnancy. Similar differences were seen with other baroreflex testing modalities. CONCLUSIONS: The normal reduction of baroreflex gain in pregnancy is further depressed in subjects with hypertensive disorders of pregnancy.

Adult↗
PubMed2001

Maternal serum levels of type I and type III procollagen peptides in pre-eclamptic pregnancy.

OBJECTIVE: To compare maternal serum levels of two markers of collagen synthesis, procollagen I carboxy-terminal peptide (PICP) and procollagen III amino-terminal peptide (PIIINP), in patients with pre-eclampsia and in controls. METHODS: PICP and PIIINP were measured by radioimmunoassay in maternal serum samples from patients diagnosed with pre-eclampsia at 32 weeks' gestation or later and in controls from the same period of gestation. For PICP, 37 cases and 36 controls were studied; for PIIINP, 12 cases and 19 controls were studied. RESULTS: Both PICP and PIIINP levels were significantly elevated in patients with pre-eclampsia. PICP and PIIINP levels were, on average, 20% and 80% higher than in controls, respectively. CONCLUSIONS: These results are in agreement with previous findings that maternal serum levels of PICP and PIIINP are mildly elevated in patients with pre-eclampsia. These markers are unlikely to be useful in the prediction of pre-eclampsia.

Case-Control Studies↗
PubMed2000

Maintenance treatment of preterm labor with the oxytocin antagonist atosiban. The Atosiban PTL-098 Study Group.

OBJECTIVES: Patients admitted with an acute episode of preterm labor who respond to early intravenously administered tocolysis remain at risk of having subsequent episodes of preterm labor and preterm delivery. Several pharmacologic agents have been used in an attempt to reduce subsequent episodes of preterm labor, and all are associated with significant side effects. Atosiban, an oxytocin receptor antagonist, is effective in the treatment of an acute episode of preterm labor. This study was designed to compare the efficacy and safety of atosiban with those of placebo maintenance therapy in women with preterm labor who achieved uterine quiescence with intravenous atosiban. STUDY DESIGN: A multicenter, double-blind, placebo-controlled trial was designed for patients in preterm labor who responded to early intravenous treatment with atosiban. Five hundred thirteen patients were randomly assigned to receive maintenance therapy, 252 to receive atosiban, and 251 to receive matching placebo. Maintenance therapy was administered as a continuous subcutaneous infusion, via pump, of 30 microg/min to the end of 36 weeks' gestation. The primary end point was the number of days from the start of maintenance therapy until the first recurrence of labor. A secondary end point was the percentage of patients receiving subsequent intravenous atosiban therapy. RESULTS: The time (median) from the start of maintenance treatment to the first recurrence of labor was 32.6 days with atosiban and 27.6 days with placebo (P =.02). At least one subsequent intravenous atosiban treatment was needed by 61 atosiban patients (23%) and 77 placebo patients (31%). Except for injection site reactions, adverse event profiles of atosiban and placebo were comparable. There were 4 neonatal deaths reported in the atosiban group and 5 in the placebo group after the start of maintenance therapy. Infant outcomes (including birth weight) were comparable between maintenance and treatment groups. CONCLUSIONS: Maintenance therapy with the oxytocin receptor antagonist atosiban can prolong uterine quiescence after successful treatment of an acute episode of preterm labor with atosiban. Treatment was well tolerated.

Adult↗
PubMed1999

Comparison of maternal serum total activin A and inhibin A in normal, preeclamptic, and nonproteinuric gestationally hypertensive pregnancies.

OBJECTIVE: The aim of the study was to compare maternal serum levels of activin A and inhibin A in pregnancy complicated by preeclampsia, pregnancy complicated by gestational hypertension, and normal pregnancy from 25 to 42 weeks' gestation. STUDY DESIGN: Activin A and inhibin A levels were measured by 2-site enzyme-linked immunosorbent assay in 60 subjects with preeclampsia, 60 control normotensive pregnant women matched for gestational age, and 51 unmatched subjects with gestational hypertension. RESULTS: Activin A levels were higher in the preeclampsia group (median 31.5 ng/mL and interquartile range 10.5 ng/mL) than in the control group (median 10.6 ng/mL and interquartile range 9.5 ng/mL, P <.0001) and the gestational hypertension group (median 21.4 ng/mL and interquartile range 15.2 ng/mL, P <.003). Inhibin A levels were greater in the preeclampsia group (median 1833 pg/mL and interquartile range 1464 pg/mL) than in control subjects (median 698 pg/mL and interquartile range 583 pg/mL, P <.0001). Control levels were significantly related to gestational age. CONCLUSIONS: Levels of both analytes were greater in preeclampsia and activin A levels were greater in gestational hypertension than in normotensive pregnancy. These analytes may prove to be clinically useful laboratory markers for preeclampsia.

Activins↗
PubMed1998

Comparison of total blood volume in normal, preeclamptic, and nonproteinuric gestational hypertensive pregnancy by simultaneous measurement of red blood cell and plasma volumes.

OBJECTIVE: Our purpose was to demonstrate reduced blood volume in preeclampsia compared with nonproteinuric gestational hypertension and normal pregnancy by use of independent measures of red blood cell and plasma volumes. STUDY DESIGN: Red blood cells labeled with a nonradioactive stable isotope of chromium and Evans' blue were infused in subjects with preeclampsia or gestational hypertension and normotensive pregnant controls. Blood was sampled eight times over 60 minutes for dye concentration and at 30 minutes for chromium analysis. RESULTS: Total blood and plasma volumes are decreased in preeclampsia (2660 +/- 382 mL/m2 and 1790 +/- 332 mL/m2, respectively) compared with normotensive subjects (3217 +/- 391 mL/m2, P < 0.001 and 2279 +/- 325 mL/m2, P < .001) and gestational hypertension (3139 +/- 272 mL/m2, P < .001 and 2132 +/- 265 mL/m2, P = .003). Total body/peripheral hematocrit ratio is increased in preeclampsia. CONCLUSIONS: Blood volume, by measurement of red blood cell and plasma volumes, is reduced and has altered distribution in preeclampsia but is normal in gestational hypertension.

Adult↗
PubMed1998

Listeriosis during pregnancy.

Listeriosis is an uncommon infection that has a unique predilection for pregnant women and may result in pregnancy loss. Contaminated food is the usual source of infection, and increased federal surveillance of foodstuffs is the most effective strategy for prevention of disease. Although dramatic epidemics have received the most publicity, more cases of perinatal listeriosis are isolated. If Listeria chorioamnionitis is diagnosed preterm, in contrast to other types of chorioamnionitis, in utero therapy with high-dose penicillin or trimethoprim-sulfamethoxazole is possible, and preterm delivery may be avoided. The clinical characteristics of neonatal listeriosis are similar to neonatal Group B Streptococcus sepsis, with early and late onset forms of disease. The epidemiology, diagnosis, and management of Listeria infection in pregnancy are reviewed.

Abortion, Habitual↗
PubMed1997

Lyme disease during pregnancy.

There has been great concern in the past regarding the possible fetal infection and teratogenicity from Lyme disease contracted during pregnancy because of the similarities of disease caused by Borrelia burgdorferi to syphilis. Although the initial retrospective case reports were alarming, more recent prospective data have been reassuring. This article reviews the evidence that currently supports the assurance of the benign nature of this infection with respect to the fetus.

Female↗
PubMed1997

Malarial infection during pregnancy.

This article reviews the parasitology of malaria, epidemiology in pregnancy, pathogenesis of increased susceptibility to infection in pregnancy, the effect of pregnancy on the clinical manifestations of malaria, the effect of malaria on perinatal outcomes, the safety of antimalarial agents during pregnancy, the role of chemoprophylaxis for inhabitants and travelers to endemic areas, and treatment of clinical malarial infections during pregnancy.

Antimalarials↗
PubMed1996

A comparison of the yield of positive antenatal group B Streptococcus cultures with direct inoculation in selective growth medium versus primary inoculation in transport medium followed by delayed inoculation in selective growth medium.

OBJECTIVE: Our purpose was to compare the yield of positive group B Streptococcus cultures with standard medium for transport of culture swabs compared with use of selective medium during transport. STUDY DESIGN: Cultures of introitus, perineum, and rectum were obtained on prenatal patients; one was placed in standard transport medium, and the other directly in selective growth medium. Swabs in standard transport medium were plated for routine culture and then transferred to selective growth medium, Todd-Hewitt broth, in the laboratory. RESULTS: A total of 307 of 1222 (25.1%) patients had a positive result by any method. With direct inoculation into selective growth medium at the time of sampling, 4.6% of positive cultures were missed. With delayed inoculation into selective growth medium, 16.3% were missed (p < 0.001). Without use of selective media (routine culture), 31.9% were missed (p < 0.001). CONCLUSIONS: Use of standard transport medium with subsequent transfer into selective growth medium results in a significantly decreased yield of positive group B Streptococcus cultures.

Bacteriological Techniques↗
PubMed1992

The effects of pH and osmolality on bacterial growth in amniotic fluid in a laboratory model.

In studying the effects of amniotic fluid on bacterial growth in a laboratory model, we noted that the pH of the fluid appeared to exert an independent effect. This study was designed to test the ability to control the growth of Escherichia coli in amniotic fluid simply by controlling two important growth conditions, pH and osmolality. The effects of pH and osmolality on growth of E. coli were systematically studied in a standard media and in amniotic fluid. Optimal ranges in standard media were pH of 5.6 to 6.6 and osmolality of 150 to 215 mOsm. When the results of growth at 24 hours were corrected for pH by analysis of covariance, the presence of amniotic fluid or phosphate had no effect. We found pH to be the only variable predictive of bacterial growth in amniotic fluid in this laboratory model.

Amniotic Fluid↗
PubMed1990

Risk factors for perinatal group B streptococcal disease after amniotic fluid colonization.

A group of 1031 parturient women at high risk for intraamniotic infection were studied. Women in whom group B streptococci grew from cultures of the amniotic fluid did not differ in clinical risk factors when compared with similar parturient women without group B streptococcal colonization of amniotic fluid. Patients who had perinatal group B streptococcal disease (maternal or neonatal bacteremia) did not differ from those without disease, by maternal or neonatal acute antibody levels or antibody response, inoculum size, or serotype of the colonizing strain.

Amniotic Fluid↗
PubMed1989

Evidence relating bacterial vaginosis to intraamniotic infection.

We performed a two-part study to determine relationships of bacterial vaginosis and intraamniotic infection. In the first part of the study, we determined whether bacterial vaginosis organisms (Gardnerella vaginalis, Mycoplasma hominis, and anaerobes) were associated with each other in the amniotic fluid of 408 cases of intraamniotic infection. In the second part, we determined the association of bacterial vaginosis itself with intraamniotic infection in 125 cases at high risk for intraamniotic infection. Strong associations were observed among the bacterial vaginosis organisms in amniotic fluid (p less than 0.01 to p less than 0.001). Women with bacterial vaginosis were more likely to develop intraamniotic infection than those without bacterial vaginosis (69% vs. 46%, p = 0.03). Women with bacterial vaginosis were more likely to have G. vaginalis and M. hominis in the amniotic fluid (p less than 0.01 and 0.04, respectively). These observations implicate bacterial vaginosis as a cause of intraamniotic infection.

Adult↗
PubMed1989

Acute hypertensive crisis in pregnancy.

Severe pre-eclampsia is a state of acute afterload increase where compensation may be total by use of the Frank-Starling mechanism and/or increased adrenergic drive, or may be uncompensated in a patient with limited or exhausted preload reserve. As such, we are presented with a diverse group of patients and antihypertensive therapy ideally should be individualized. In reality we are dealing with a complex situation because of the presence of the fetus raising concerns about direct effects on the fetus as well as on uteroplacental blood flow. This limits our choice of agents to those with extensive use in pregnancy except in complicated or resistant cases. For these reasons, hydralazine is the antihypertensive agent of choice for treatment of acute hypertensive emergencies in pregnancy. In the complicated case other agents such as sodium nitroprusside or nitroglycerin may be more appropriate and, in these cases, hemodynamic monitoring should be performed to allow not only greater safety, but also to tailor therapy to the individual hemodynamic profile.

Acute Disease↗
PubMed1978

Symptomatic osseous sarcoidosis with findings on bone scan.

Twenty-one years after the onset of sarcoidosis, a 51-year-old woman experienced pain in the lower portion of her back, which proved to be the result of sarcoidosis involving the pelvis. The pelvic abnormality consisted of osteosclerotic and osteoblastic lesions. A bone scan showed several other areas of increased uptake, and the diagnosis was confirmed by bone biopsy. The patient improved with treatment with steroids, but the findings on the x-ray film and the bone scan did not change. Sarcoidosis may cause obscure, but symptomatic, osseous lesions.

Adult↗