Chan, KH

Cheung, RTF

Ho, SL

Mak, W

Tsang, KL

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Title Think about cryptococcal meningitisAuthor(s) Chan, KH; Tsang, KL; Mak, W; Cheung, RTF; Ho, SLCitationThe 5th Medical Research Conference (MRC 2000), Hong Kong,China, January 2000. In The Hong Kong Practitioner, 2000, v. 22suppl. 2, p. 15Issued Date 2000URL http://hdl.handle.net/10722/46819Rights Creative Commons: Attribution 3.0 Hong Kong LicenseG-N-3THINK ABOUT CRYPTOCOCCAL MENINGITISK H Chan. K L Tsang, W Mak, RTF Cheung, S L Ho Division of Neurology, University Department ofMedicine, Queen Mary HospitalCryptococcus neoformans is regarded as an opportunistic infectious agent for human beings and untreatedcryptococcal meningitis has a very high mortality rate. However, occasional cases of cryptococcal meningitisoccur in apparently normal individuals. This study aims to identify cellular and humoral immunity defects incryptococcal meningitis. From May 1996 to June 1999, all patients with CSF culture confirmed cryptococcalmeningitis are studied. Peripheral lymphocyte count, HIV antibody titre, serum immunoglobulin levels aremeasured; lymphocyte subset profile by flow cytometry and lymphocyte function test are performed for thosewith no obvious causes of immunocompromise found. A total of 6 patients are identified and two hadlymphopenia with positive HIV antibody tests; one patient had dermatomyositis and lymphopenia while takingoral prednisolone and cyclophosphamide. For the three patients with no obvious cause found, one had reducedCD4+ T helper cells on lymphocyte subset profile and diagnosed as idiopathic CD4 lymphopenia; the othertwo had normal lymphocyte subset profiles but impaired lymphocyte function tests in terms of proliferativeresponse to phytohaemagglutinin and pokeweed mitogen. All six patients have normal serum immunoglobulinlevels. In conclusion, it seems that all patients with cryptococcal meningitis are immunocompromised in someways though the exact underlying causes need further investigations, this is important as immunocompromisedpatients with cryptococcal meningitis require long term prophylactic antifungal agents until immunocompetenceis restoredG-N-4IN VIVO NEUROPROTECTION OF MELATONIN AGAINST FOCAL CEREBRAL ISCHAEMIAIN THE RATZ. Pei. H.T.S. Ho, S.F. Pang*, and R.T.F. Cheung, Departments of Medicine and Physiology*, Faculty ofMedicine, The University of Hong Kong, Hong KongBackground and Purpose: Melatonin, the neurohormone secreted predominantly by the pineal gland, plays akey role in the synchronisation of diurnal rhythms in mammals. Melatonin protects against experimental braininjury and global cerebral ischaemia. Deficiency of Melatonin after pinealectomy was found to increase theinfarction volume of middle cerebral artery occlusion (MCAO) in rats. In this study, the neuroprotectiveeffects of exogenous Melatonin were tested in a MCAO stroke model.Methods: Adult male Sprague-Dawley rats were anaesthetised with sodium pentobarbital to undergo 3-houror permanent endovascular right-sided MCAO. Melatonin (1.5, 5, 15, or 50 mg/kg) or the vehicle was given asa single intraperitoneal (IP) injection at 0.5 hour before the 3-hour MCAO. Another group of rats received anIP injection of Melatonin (5 mg/kg) at 0.5 hour before permanent MCAO. Body temperature was maintainedconstant, and haemodynamic parameters were continuously monitored during the anaesthesia. The rats weredecapitated on day 3, and their brains were cut into 2mm coronal slices before being stained with 2%triphenyltetrazolium chloride for determination of infarction volume.Results: After MCAO for 3 hours, the relative infarction volumes were 32.1± 3.9% (mean ± SEM; 11 rats) inthe vehicle-treated group and 27.7±3.8% (10 rats), 17.3+3.4% (9 rats), 24.6±4.5% (9 rats), or 27.7±3.2%(9 rats) in the groups treated with Melatonin at 1.5, 5, 15, or 50 mg/kg, respectively. The relative infarctvolume was 17.0± 6.5% (8 rats) after the permanent MCAO and an IP dose of Melatonin at 5 mg/kg. In both3-hour and permanent MCAO, the reduction in infarction volume was statistically significantly with an IPdose of Melatonin at 5 mg/kg (P < 0.05, 2-tailed student's t test). There was no significant difference in thehaemodynamic parameters among all the groups.Conclusions: Exogenous Melatonin at 5 mg/kg protects against both transient (3 hours) and permanent focalcerebral ischaemia in the rat, when given as a single IP dose at 0.5 hour before the MCAO. Both the non-receptor mediated (such as antioxidant effects) and receptor-mediated actions of Melatonin may influence theinfarction volume of focal cerebral ischaemia. Melatonin at the present doses does not produce any significanthaemodynamic effect.- 15 -

Think about cryptococcal meningitis

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Think about cryptococcal meningitis

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