Spontaneous subarachnoid hemorrhage in pregnancy; a case report

The case reported is added to the literature in order to show that vaginal delivery with adequate sedation, regional anesthesia, and low forceps delivery is probably a safe method of delivery under these circumstances.     

Identification of the origin of cells in human basal cell carcinoma xenografts in mice using in situ hybridization

In an attempt to identify more clearly the origin of cells in human basal cell carcinoma xenografts in mice, paraffin and frozen sections were subjected to in situ DNA hybridization with biotin labelled human and murine DNA probes. Human skin and mouse skin sections were used as controls. As expected, the implanted epithelium reacted with the human DNA probe and the surface epithelium and most of the stromal cells reacted with the murine probe. However, the stroma immediately surrounding the implanted epithelium contained cells of human origin mixed with murine cells. Occasional murine cells (presumed inflammatory) were present in the human implanted epithelium. Assessment showed no correlation between the degree of differentiation of the implanted epithelium and the ratio of human/murine cells in the contiguous stroma. This technique provides a sensitive test for identifying human cells in xenografts and may be useful in assessing the role of stromal cells in the differentiation of a variety of carcinomas.     

The profitability of ''guessing'' in multiple choice question papers

Candidates taking multiple choice question (MCQ) papers in which marks are deducted for wrong answers often omit many items for fear of losing marks. In an MCQ paper in 1985 candidates who omitted many items made relatively few errors; they were not necessarily much less able than those who omitted few items. Those who had omitted many items were interviewed and advised to answer more, including those about which they were uncertain but not totally ignorant; the same advice was given to the whole group before they took another MCQ paper in the same subject in 1987. In 1987 there were large changes in the numbers of items omitted and, in particular, those who had omitted many items in 1985 answered many more in 1987. They also made more errors; despite this they tended to improve their performance in relation to their colleagues. A clear relationship was shown, for the whole group, between an increase in the number of items attempted and a rise in the rank order. The effects on candidates' behaviour of deducting marks for wrong answers and of permitting them to omit items are reviewed and the nature of the advice which should be given to candidates taking such examinations is discussed.     

Ultrasound exposure time in routine obstetric scanning

Summary. The duration of exposure to ultrasound was measured in 1274 patients having a routine examination during their first visit to an antenatal clinic. The measured median exposure time was 105 s. Since pulsed ultrasound was used (duty cycle of 1 in 800) the actual median maternal exposure time was 131 ms. Exposure of the fetus would usually be less since it rarely occupies the full width of the image. The relevance of exposure time to the safety of diagnostic ultrasound and the implications for users and manufacturers are discussed.     

Phospholipids in Guinea Pig Spermatozoa Before and After Capacitation In Vitro

Phospholipids of guinea pigs spermatozoa were examined using high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). Two types of spermatozoa were compared: fresh epididymal (uncapacitated) spermatozoa and epididymal spermatozoa preincubated in Ca2+-free medium for 17-18 hr (capacitated spermatozoa). Determination of lipid phosphorus revealed that the total phospholipid content of spermatozoa did not change significantly during capacitation of spermatozoa. HPLC analyses of choline and ethanolamine phosphatides, lysophosphatides, and sphingomyelin revealed that the relative amounts of these phospholipids remained unchanged during capacitation. In contrast to spermatozoa, phospholipids in the medium surrounding spermatozoa reduced by 20% during capacitation of spermatozoa, suggesting that spermatozoa may utilize extracellular phospholipids as possible energy sources during their capacitation.     

PREDICTION OF OVULATION IN WOMEN USING A RAPID PROGESTERONE RADIOIMMUNOASSAY

A rapid (3-h) radioimmunoassay of plasma progesterone has been developed and used successfully to predict the time of ovulation in women undergoing artificial insemination. The results obtained using progesterone levels to date the stage of the cycle were analysed retrospectively by (1) estimation of the length of the ensuing luteal phases and comparison of these with luteal phase lengths of a control group (2) comparison of the dating using progesterone levels with retrospective determination of LH values and (3) by analysis of the dating in cycles in which conception occurred.