Rapid method for differentiating strains of Branhamella catarrhalis.

The ability of Branhamella catarrhalis to cause nosocomial infections is a matter of some controversy. The API ZYM research kit for detecting 89 enzymes was used on 49 isolates of B catarrhalis to select enzymes of potential use in differentiating clinical isolates. Twenty nine enzymes were produced by all isolates (13 strongly positive) and many of these were esterases; 16 enzymes were not detected in any isolate (40 if a more stringent criterion was used). Twenty enzymes were selected to form a prototype biotyping panel which allowed 17 different patterns of reactivity to be recognised. Of the 49, 34 isolates were confined to the three commonest patterns. Only one isolate was untypable using this panel due to lack of reactivity. A kit with these 20 substrates may be sufficiently discriminatory to be useful in the rapid study of outbreaks of infection caused by B catarrhalis.     

The treatment of Guillain-Barré syndrome by modified plasma exchange--a cost effective method for developing countries

Six patients with the Guillain-Barré syndrome were treated by modified plasma exchange. Five of them showed a rapid improvement which was not consistent with the natural history of the disease. The improvement was assessed by monitoring vital capacity and muscle power, grading the ability to perform motor functions and by the duration of the hospital stay. The method of plasma exchange we used was simpler and cheaper than the conventional method. We recommend the use of our method, especially in developing countries with financial constraints and poor facilities.     

Anopheline ecology and malaria infection during the irrigation development of an area of the Mahaweli Project, Sri Lanka

A study on adult anopheline ecology and malaria vector incrimination was carried out from 1986 to 1989 during irrigation development in an area of the Mahaweli Project in eastern Sri Lanka. Eleven potential vector species were collected resting indoors or by using human or bovid bait, and from light trap catches. Overall, Anopheles vagus (Donitz), An. annularis (van der Wulp), and An. subpictus (Grassi) were the most prevalent, and An. culicifacies (Giles) and An. barbirostris (van der Wulp) were the least prevalent species. The abundance of An. aconitus (Donitz), An. jamesii (Theobald), An. pallidus (Theobald), and An. subpictus increased after irrigation development, while An. annularis, An. barbirostris, An. culicifacies and An. varuna (Iyengar) decreased. Populations of An. nigerrimus (Giles), An. tessellatus (Theobald), and An. vagus did not change substantially. Seven species were infected with malaria parasites, as determined by enzyme-linked immunosorbent assays (ELISA) done on mosquito head-thorax triturates. The main species involved were An. annularis, at peak abundance during the 1986-1987 period of development leading to the onset of irrigation, and An. subpictus, during times of seasonal abundance in the post-irrigation period of 1988 to 1989. Although occurring at low abundance, An. culicifacies was involved in malaria transmission irregularly throughout the study period. While there was strong ELISA-based evidence implicating An. subpictus as a major post-irrigation vector, confirmation of its vector status must await dissection and ELISA-based evidence of P. vivax and P. falciparum sporozoite infection rates in salivary glands.     

Effects of hyperkalaemia on the excitability of peripheral nerve

An experimental animal model has been developed for the study of excitability change in peripheral nerve during limb ischaemia. This model has been used to investigate the effects of hyperkalaemia on the sequence of excitability change that occurs during cuff-induced limb ischaemia and in the post-ischaemic recovery period. The results lend support to the hypothesis that the dynamics of K ion concentration in the periaxonal space play a critical role in determining these excitability changes and that the polyanionic mucopolysaccharide gap substance of the node of Ranvier is likely to constitute the diffusion barrier that defines the periaxonal space.