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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

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

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

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

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

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