Biomedical subjects
Publications and source records attributed to N Pyndiah.
The Indian Ocean provides a unique opportunity to curb the HIV epidemic in its nascent phase through strengthening STI control programmes. Making effective and appropriate health services available should be regarded as the first priority for STI control in the region and, whenever possible, core groups should be identified and targeted to interrupt transmission within such networks.
530 human faecal samples were examined for the presence of rotavirus by electron microscopy (EM) and by a modified electrophoretic analysis of viral genome (PAGE). 516 stools gave identical results by both methods (97.4% agreement). The proportion of EM+, PAGE- samples (1/530) was significantly lower than the proportion of EM-, PAGE + samples (13/530) (P less than 0.01 with McNemar test). Relative sensitivity was 99.6% for PAGE and 95% for EM. False positive results could be excluded for each method because of the characteristic morphology of rotavirus particles (EM) and specificity of rotavirus electrophoretypes (PAGE). Discrepant cases were reexamined whenever possible and the causes of misdiagnosis are discussed.
The PAP-(peroxidase-antiperoxidase)-immunohistochemical method was tested for rapid diagnosis on corneal specimens in clinically suspected herpetic disease. The method proved accurate, easy and useful in rapid diagnosis of corneal specimens from epithelial keratitis. Corneal buttons after keratoplasties for herpetic lesions were similarly tested for the presence of herpetic antigen. In a total of five corneal buttons, antigen was found in two corneas with necrotizing keratitis, whereas it was not noted in the three corneas opacified by disciform edema.
The usefulness of screening for presence of fecal leukocytes has been investigated prospectively in 87 ambulatory patients with diarrhea. This simple test has proved valuable in helping to select patients for whom laboratory studies of stools for etiologic agents are indicated.
During a 2-year period 5 previously healthy young men who had undergone splenectomy and received multiple transfusions for trauma had severe cytomegalovirus (CMV) infection. Their illness was characterised by a long period of high fever, severe interstitial pneumonitis with dyspnoea and hypoxaemia, and an unusually high lymphocytosis (12 000-26 000 cells/microliter) with numerous atypical forms. The presumptive diagnosis was based on the patients' seroconversion and viral excretion, on the clinical and haematological findings which were typical of severe CMV infection, and on the absence of other infective organisms. In 1 case widespread CMV pneumonitis was confirmed at necropsy. These observations raise the possibility that splenectomy increases the severity and modifies the pattern of CMV infection, since during the same period no other case of severe CMV infection was observed among a large number of patients who had received multiple transfusions but had not undergone splenectomy.
The indirect immunofluorescent (IIF) antibody technique for the detection of Toxoplasma gondii immunoglobulin M (IgM) often gives false negative results, probably due to the competition between IgG and IgM. We therefore adapted a gel filtration procedure for the separation of IgG and IgM to a routine diagnostic test capable handling at least 10 sera per day and requiring only 50 microliters of serum. The results from 108 sera having positive complement fixation titers for Toxoplasma showed that 17 were IgM positive when the whole serum was tested by IIF compared with 55 positive when the IgM fraction was used. Sera with antideoxyribonucleic acid titers do not give false positive results after fractionation, and the removal of IgG eliminates false positive results due to rheumatoid factor. A prospective study showed that Toxoplasma IgM may persist up to 9 months.
A polystyrene plate is described which was designed to replace microscope slides for routine immunofluorescent examinations. The plate has 40 flat indentations of 8 mm diameter. The plates can be sterilized and stored in plastic bags. They are well suited for drop preparations or application of cryostat slices of biopsy and necropsy material, and tissue cultures can be grown directly in the indentations. When compared with glass microscope slides, which have long been used for these purposes, the polystyrene plates offer a variety of advantages. Cells can be grown directly in the indentations without washing or pretreating the trays in any way. The indentations prohibit mixing of samples or reagents and enable the use of smaller quantities of reagents. Up to 40 samples can be worked up simultaneously on one plate, or a plate rack can be used for the processing of up to 400 samples at once. The use of a special stage enables easy microscoping of all 40 spots without further handling of the tray.