Sudden death during long distance air travel in an Hb S/C disease patient.

Sickle cell disease is an inherited disorder and individuals who are homozygous for the sickle cell gene (HbS/S) show the clinical manifestations of the disease. The individuals who are heterozygous for the sickle cell gene (HbA/S) are referred to as sickle cell trait. In these people, under normal circumstances, symptoms are usually absent or mild. However, thorough investigation of the latter condition is also important, because sickling could occur under certain situations, such as prolonged hypoxia. The level of haemoglobin S(HbS), the ratio of HbS to haemoglobin A (HbA) and the presence of variants such as haemoglobin C (HbC) can alter the entire course of the condition. An unexpected sudden death in a 41-year-old Nigerian, who was apparently in good health and was on a long duration flight, is presented. According to available evidence he was previously diagnosed to be suffering from sickle cell trait. Based on medical advice oxygen was supplied to him throughout the flight. Two hours prior to landing at the international airport in Kuala Lumpur, Malaysia he suddenly became breathless and died shortly after. Autopsy revealed that the immediate cause of death was pulmonary thrombo-embolism originating from calf vein thrombosis. It was also established that the thrombus in the calf vein was not pre-existing. Histology revealed that there was extensive and generalized sickling. Haemoglobin electrophoresis on the postmortem sample of blood confirmed that the deceased had Hb S/C disease and not sickle cell trait. The presence of HbC together with the long hours of flight and associated inactivity had probably complicated the case. Various aspects of the sickle-cell condition are highlighted. Allegations of negligence were made against the airline and the doctor who cleared the deceased in Nigeria (the deceased was employed in a well-known multinational company) for long distance non-stop air travel. Various medico-legal issues pertaining to the cause and mode of death, the importance of an accurate diagnosis of the precise sickling disorder and possible negligence on the part of various agencies are discussed.

HIV type 1 subtypes in Malaysia, determined with serologic assays: 1992-1996.

We investigated the molecular epidemiology of HIV-1 subtypes in Malaysia among injecting drug users (IDUs) and sexual transmission risk groups, using serologic and genetic techniques. Frozen sera collected at a general hospital, a blood bank, several drug treatment centers, and an STD clinic in Kuala Lumpur, between 1992 and 1996, were investigated retrospectively. V3 peptide serotyping and monomeric gp120 capture serotyping were used to study 89 known HIV-1-infected subjects. The methods differentiate subtypes B, E, and C. V3 peptide and gp120 capture results were comparable. No subtype C-specific reactive sera were found; one specimen was dually reactive for subtypes C and B, using the V3 peptide ELISA; and four were durally reactive for subtypes E and C using this assay. Genotypic analysis of HIV-1 gag RNA in serum was done on a subset of subjects and confirmed serologic findings. HIV-1 subtypes differed significantly by risk category: of 53 IDUs, 29 (55%) were infected with subtype B and 19 (36%) were infected with subtype E, 3 (6%) were dually reactive, and 2 (4%) were not typable. Of 36 persons with heterosexual risks, 29 (81%) were infected with subtype E, 5 (14%) were infected with subtype B, and 2 (5%) were not typable. Persons with IDU risks were significantly more likely to be infected with subtype B than were those with sexual risks (OR 5.89; 95% CI, 1.94-18.54; p < 0.001). Subtypes B and E of HIV-1 appear to predominate in Malaysia; subtype B was more prevalent among IDUs; subtype E was more prevalent among all other groups. These results may have important HIV-1 vaccine implications.

The prevalence of anti-HCV antibody in risk groups and blood donors.

Anti-HCV antibody was detected in 1.9% of the blood donors in University Hospital. Among the risk groups, 33.3% of the patients with post-transfusion hepatitis were tested positive for anti-HCV antibody. The anti-HCV antibody was detected in 30% of the IDU. Haemodialysis patients, patients with acute and chronic hepatitis and patients with liver cirrhosis appeared to have increased risk of Hepatitis C virus infection. The results indicate that the frequency of HCV infection increases with the exposure to blood or blood products.

Release of prostaglandin E2 by human mononuclear cells exposed to heat-killed Salmonella typhi.

Human mononuclear cells pre-labeled with [3H]arachidonic acid were shown to release metabolites following in vitro addition of heat-killed Salmonella typhi (HKST). The amount of label released was significantly higher than that seen with live S. typhi (LST). Addition of increasing amounts of HKST resulted in an increased release of metabolites. Enzyme immunoassay of the culture supernatants revealed that the bulk of the metabolite released was prostaglandin E2 (PGE2). Leukotriene B4 (LTB4) and leukotriene C4 (LTC4) were not detectable in the culture supernatants. The significance and implications of these results are discussed.