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Biomedical subjects

S R Carr

Publications and source records attributed to S R Carr.

7 recordsLinked to original sources

Treatment of antenatal myasthenia gravis.

Maternal myasthenia gravis has been associated with the presence of neonatal myasthenia and sometimes fatal congenital anomalies. As a result, antenatal therapy directed at fetal sequelae may be indicated. We present the case of a pregnant myasthenic woman whose two previous pregnancies had ended in neonatal deaths from fetal deformations that were presumably due to maternal myasthenia. Serial plasmaphereses and oral prednisone therapy were used in an attempt to depress maternal anti-acetylcholine receptor antibody titers. As anti-acetylcholine receptor antibody titers fell, fetal breathing movements became apparent by ultrasound, and as these titers rose, no fetal breathing movements were apparent. Our patient delivered an infant with transient neonatal myasthenia but normal pulmonary development and no deformations. We suggest that the therapy given may have improved the outcome of this pregnancy compared with her two previous pregnancies.

Administration, Oral

Survival rates of monoamniotic twins do not decrease after 30 weeks' gestation.

A search of pathology records from the years 1967 to 1988 at Women and Infants' Hospital of Rhode Island (138,232 live births) revealed 24 sets of histologically confirmed monoamniotic twins. All records were available for review. Among the 17 sets of monoamniotic twins that reached 30 weeks' gestation with at least one twin still alive, there were no further fetal deaths. The risks of early delivery in these pregnancies appear to outweigh the risk of fetal death as a result of monoamniotic status alone. These data do not show an advantage to early delivery.

Female

Maternal age and screening for gestational diabetes: a population-based study.

The American College of Obstetricians and Gynecologists (ACOG) has recommended screening for gestational diabetes, using a 50-g, 1-hour glucose challenge (threshold for further testing 140 mg/dL or higher), for all pregnant women aged 30 or older and for younger women with risk factors. In order to assess these recommendations, we collected demographic and historic data on 6214 pregnant women representing a population of universally screened individuals. Of 125 cases of gestational diabetes diagnosed (ACOG criteria), 70 patients (56%) were under the age of 30. In addition, 44% of gestational diabetics had no risk factors. The cost per case diagnosed would be $190 with the ACOG recommendations, $192 if the age for routine screening were lowered to 25 years or more, and $222 if universal screening were practiced. Using the ACOG recommendations, 35% of gestational diabetes would go undiagnosed, with little cost savings.

Adult

Spasmogen release from an extracranial vascular bed evoked by neurohumoral stimuli and periods of vascular stasis.

The hypothesis that pro-inflammatory spasmogens may be generated locally in the vessels of the head by neurohumoral stimuli has been tested using an isolated extracranial vascular bed from the rabbit. No spasmogen release was detected after adenosine triphosphate, histamine, acetylcholine or noradrenaline and was seen rarely after tyramine and 5-hydroxytryptamine. Both sympathetic nerve stimulation and periods of vascular stasis released spasmogen, probably an E-type prostaglandin. The local generation of pro-inflammatory substances by excess sympathetic stimulation and/or vascular stasis might contribute to the development and maintenance of the acute migraine attack.

Acetylcholine

Variable ammonia production among smooth and rough strains of Pseudomonas pseudomallei: resemblance to bacteriocin production.

The colonial morphology of some strains of Pseudomonas pseudomallei was correlated with certain biochemical and physiological traits. After 3 days of growth on Wahba or heart infusion agars, smooth-colony strains generated toxic amounts of ammonia. Under the same conditions, the rough strains simultaneously produced oxalic acid which decreased the inhibitory concentration of ammonia. The ammonia-ammonium concentrations in smooth cultures exhibited certain bacteriocin-like characteristics. An unusually stable, smooth strain (strain 165) was chosen to compare and emphasize any differences with typical, rough strain 7815. Three-day-old smooth cultures grown on Wahba agar containing 3% (w/v) glycerol demonstrated ammonia toxicity. The substitution of glucose for glycerol completely obviated this toxicity. In highly aerated Wahba broth containing glucose, the amount of ammonia found in strain 165 smooth cultures and the amount of oxalic acid found in strain 7815 rough cultures were greatly reduced. In Difco nitrate broth smooth strain 165 did not form gas, and it reduced nitrate to nitrite only. Strain 7815 produced a gas and reduced both nitrate and nitrite.

Ammonia