[Sawdust in autopsies: production, spreading, and contamination]. / Knochenstäube bei der Autopsie. Entstehung, Ausbreitung, Kontamination.

Airborne infections are well known in clinical medicine (transport of bacteria by aerosols). During autopsies floating, respirable kinds of bone dust are produced, depending on the type of saw. Experiments were carried out with oscillating saws (without/with exhauster) and manual saws (autopsy of cranial cavity). The intention was to characterize and quantify the sawdust produced by the different saws. Furthermore, we wanted to find out whether bacteria are transported by these aerosols. Bone dust was collected with adhesive microscopic slides. Alizarin red was used for solid histochemistry of bone particles. Quantification was carried out by an eyepiece micrometer. Airborne particles and bacteria were identified macroscopically per unit of time. The oscillating saw without exhauster produced sawdust in large quantities. This dust was respirable and had suspension power for hours. There was a remarkable reduction of sawdust by an integrated exhauster. Spreading of particles carrying bacteria/saccharomycetes was seen over 6-8 m. There is a very low risk of an airborne infection when utilizing a manual saw (production of particles similar to chippings, absence of suspended sawdust). It is necessary to take every precaution against airborne infections by wearing breathing masks and safety goggles when using an oscillating saw.

Bone-dust in autopsies: reduction of spreading.

During autopsies, an open oscillating saw produces large quantities of respirable bone-dust, which is able to carry microbes over several metres. Experiments were done using a modified (open) undulation saw (spray tube to moisten the saw-blade with water). Saw-dust was asservated with culture media. Colonies were identified macroscopically. Microbes in the air were quantified (per unit of time). A remarkable reduction of saw-dust is done by an integrated spray tube using water. There remains a contamination at the head of the autopsy table in the level of the table top. We found a complete decontamination 150 cm above the floor. No spreading of particles carrying microbes was seen over distances of more than 1.5 m. The risk of an airborne infection is minimal when using a manual saw (absence of grinding-dust). The modified type of an 'oscillating saw with a spray-tube' may be considered a practicable compromise between a manual saw and an unprotected undulation saw. It is necessary to complete the precautions against airborne infections by breath masks and safety-goggles.

Prolonged haemolytic anaemia in malaria and autoantibodies against triosephosphate isomerase.

Prolonged haemolysis may accompany infection with Plasmodium falciparum. We observed prolonged haemolysis in 4 of 10 patients with this type of malaria after parasitological cure. IgM antibodies specific for the glycolytic enzyme triosephosphate isomerase were detected in these patients' sera. Clinical recovery and a decrease in haemolysis coincided with a fall in these autoantibodies. In vitro, affinity purified autoantibodies isolated from the sera directed against triosephosphate isomerase induced lysis of erythrocytes and activation of complement as shown by the 51Cr release assay. We assume that autoantibodies against triosephosphate isomerase contribute to the development of prolonged haemolysis and anaemia in P falciparum malaria.

Hexadecylphosphocholine: oral treatment of visceral leishmaniasis in mice.

Hexadecylphosphocholine (He-PC), a novel phospholipid derivative, was tested against Leishmania donovani and Leishmania infantum, the causative agents of visceral leishmaniasis. In vitro, promastigotes were highly susceptible to He-PC; the 50% inhibitory concentrations were between 0.89 and 2.25 micrograms/ml for the different leishmanial strains. In vivo, a marked antileishmanial activity in infected BALB/c mice could be demonstrated after oral administration of He-PC. Whereas parasite suppression and killing in the liver were comparable after 5 days of treatment with He-PC (10 or 20 mg/kg of body weight per day administered orally) and sodium stibogluconate (120 mg of pentavalent antimonal agent per kg/day administered subcutaneously), a superior reduction in the parasite load in the spleen and bone marrow was observed after oral treatment with He-PC. After a 4-week treatment period, parasite suppression in the spleen was better than that observed with standard sodium stibogluconate therapy by a factor of more than 600.

Studies on the pathogenesis of Acanthamoeba-associated meningoencephalitis.

100 indoor swimming pools were examined for the presence of free-living amoebae. Limax amoebae of the genus Acanthamoeba could be isolated from 34 samples. Naegleria spp. were not present. After axenic cultivation the pathogenicity in mice was tested. Histological as well as immunohistological procedures were compared in order to identify the amoebae in brain sections and to clarify the route of infection. The results indicate a direct invasion of the central nervous system by acanthamoebae via the nasal mucosa and the olfactory bulb.