Diffusion coefficient determination using a filter-paper diaphragm cell technique.
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Biomedical subjects
Publications and source records attributed to R Fleming.
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Ovarian function in pregnant women at term was investigated by obtaining plasma samples from both ovarian veins simultaneously with a peripheral sample from the antecubital vein. All samples were analyzed by radioimmunoassay to determine the concentration of progesterone, estradiol, estrone, androstenedione, testosterone, and human chorionic gonadotropin. The corpus luteum was found to secrete progesterone and not significant amounts of estrogens or androgens. Extraluteal tissue secreted estrogens and androgens and also progesterone. No quantitative relationship was found between the concentrations of human chorionic gonadotropin and any ovarian steroid, and estradiol appeared to be produced from both estrone and testosterone.
Human ovarian follicular development measured by peripheral plasma hormone levels and ovarian follicular growth assessed by ultrasonic visualization of the ovary were compared and contrasted in apparently normally menstruating women. The linear correlation coefficient between the mean values for plasma estradiol and follicular diameter on day -5 to day 0 of 15 normal cycles was r = 0.968. When the individual paired data were subjected to multiple linear regression analyses (on days -5 to 0), r = 0.771. These good correlations show that ultrasound measurements of follicular diameter are valuable in the assessment of follicular growth and development. Observations on apparently abnormal cycles are also discussed. Ultrasound measurement of follicular diameter offers an additional technique for the study of ovarian function.
Recent developments in the study of violent behaviour have led social scientists to examine the concept of Overcontrolled Hostility. This case report describes the history of an overcontrolled individual who was examined in a Maximum Security Hospital after having shot his wife. The presentation of this case includes a brief theoretical perspective, as well as the results of psychiatric and psychological examinations.
Trigeminal neuralgia was the presenting symptom in two patients with aqueduct stenosis, hydrocephalus, and raised intracranial pressure. Treatment of the hydrocephalus resulted in the remission of pain in both patients.
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The distribution, seasonal variation, origin, and significance of biological nitrogen fixation has been determined for a Chesapeake Bay estuary using the acetylene reduction technique. Studies over a 15-month period have shown that nitrogen fixation occurs predominantly in the surface intertidal (marsh) and subtidal sediments. Negligible activity was found in surface waters. A marked seasonal variation in nitrogen fixation was observed for intertidal sediments incubated at a standard 20 degrees C. Average rates of about 37 and 12 ng N/g dry sediment per hour were observed in the late fall months of 1972 and 1973, respectively, and less than or equal to 5 ng N/g dry sediment per hour during other seaons. Peaks of activity were lowered considerably when samples were incubated at ambient temperatures (in situ). Activity in the subtidal sediments was low (less than or equal to 6.8 ng N/g dry sediment per hour but showed a similar (approximately twofold) seasonal variation in nitrogen fixation potential. Light-dark and substrate addition experiments suggest that heterotrophic bacteria are the principal agents for nitrogen fixation in sediments. Integrated estimates of nitrogen fixation in the estuary indicate that biological fixation probably accounts for less than 5% of the total influx of nitrogen into the system. Rates of activity in the intertidal sediments are insufficient to account for the high productivity of marine angiosperms found in the marsh.
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