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M B Markus

Publications and source records attributed to M B Markus.

At least 19 recordsLinked to original sources
PubMed1998

Anti-Acanthamoeba activity of contact lens solutions.

AIMS: This study was undertaken to investigate the effects of contact lens disinfecting solutions on strains of Acanthamoeba from the United Kingdom and southern Africa and to compare the results with those of other researchers. No information was previously available for southern African isolates. METHODS: 11 contact lens solutions were tested on cysts of 10 strains of Acanthamoeba. RESULTS: Not all solutions used in the study were effective, with some for hard and gas permeable contact lenses being more satisfactory than those for soft contact lenses. The most effective of the gas permeable and hard contact lens solutions tested was Transoak (0.01% (wt/vol) benzalkonium chloride), which killed cysts of all strains within 4 hours of exposure. Oxysept 1 (31 mg hydrogen peroxide/ml) was the best soft contact lens solution tested. It eliminated cysts of certain strains within 4 hours, whereas cysts of other strains were only inactivated within either 8 or 72 hours. CONCLUSIONS: Manufacturers should be aware of the killing time for Acanthamoeba by contact lens solutions and should provide appropriate guidelines for the use thereof. The killing time for cysts of the African and UK isolates studied is, in general, similar. Therefore, it must in the present state of knowledge be assumed that usage guidelines suggested in the UK are also appropriate for travellers to South Africa and for local residents in South Africa.

Acanthamoeba↗
PubMed1998

Cytopathogenicity of clinical and environmental Acanthamoeba isolates for two mammalian cell lines.

The cytopathic effect (CPE) of southern African, British, and an Asian strain of Acanthamoeba was assessed using a system developed around 2 different mammalian cell (MC) lines. The time taken by the amebae to destroy cell cultures completely was shown to be dependent largely on the size of the amebic inoculum and the cell type. This highlights the need to assess carefully the behavior of cell lines prior to using them for cytopathic testing. Assays performed with conditioned medium collected from both MCs and amebic cells indicated that mechanical destruction may have been primarily responsible for the CPE. Furthermore, not all strains of Acanthamoeba lose cytopathogenicity after being passaged in axenic culture for extended periods. The use of MC cultures was shown to be an accurate, rapid, and repeatable means of assaying the CPE of strains of Acanthamoeba.

Acanthamoeba↗
PubMed1995

Anti-Mastigina activities of eight contact lens solutions.

The effects of eight contact lens solutions on a Mastigina sp., which was associated with the infected eye of a patient, were studied. The solutions which killed the organism promptly were those which are used for gas-permeable and hard contact lenses. Some solutions for soft contact lenses were more effective than others.

Acanthamoeba↗
PubMed1994

Observations on the techniques used in the qualitative and quantitative diagnosis of schistosomiasis.

For many years, the Visser filter has been used in various laboratories in South Africa for the qualitative and quantitative diagnosis of human schistosomiasis. In the present study, the effectiveness of the Visser filter was compared with those of the urinalysis method for urine (involving the use of small transparent filters in Millipore filter holders attached to 10-ml syringes) and the Kato-Katz thick smear method for faeces. The Visser filter was the most sensitive in detecting ova in human excreta. Furthermore, there was little agreement between the egg counts obtained using the Visser filter and those obtained with the other two techniques. The Visser filter owes its effectiveness and superior sensitivity to the fact that, compared with the other two techniques, larger quantities of urine (total bladder contents) and stool (up to 5 g) can be easily processed.

Child↗
PubMed1994

Necrotic encephalitis as a manifestation of acute sarcocystosis in cattle.

Extensive brain pathology attributed to Sarcocystis is described in a heifer and a 2- to 4-month-old calf. These appear to be the first recorded cases of naturally occurring acute sarcocystosis in cattle in sub-Saharan Africa. The heifer became recumbent and had convulsions before dying, while clinical signs in the calf included loss of body mass, diarrhoea, nervousness and opisthotonus. Disseminated haemorrhages were noted in the brains of both animals at necropsy. Microscopically, the grey and white matter contained multiple areas of necrosis associated with haemorrhage, fibrinoid vasculitis, perivascular cuffing and gliosis. A multifocal meningitis was also present. First-generation Sarcocystis schizonts were evident in, or adjacent to endothelial cells of several arterioles and small arteries. The association of first- (as opposed to second-) generation schizogony with overt and fatal bovine sarcocystosis, has not previously been reported.

Animals↗
PubMed1993

In vitro sensitivity of southern African isolates of Plasmodium falciparum to halofantrine.

Twenty southern African isolates of Plasmodium falciparum and a 'control' Gambian strain were tested in vitro for their sensitivity to halofantrine. The concentration required to inhibit 50% of parasite growth, the IC50, ranged from 0.039 to 15.000 nmol/litre, with a mean of 4.619 nmol/litre. These IC50 values were comparable with those obtained in studies carried out in West Africa but were higher than the IC50 of South-East Asian isolates. All 21 isolates examined in the present study had minimum inhibitory concentrations (MIC) of 32 nmol/litre or less, with a median MIC value of 8 nmol/litre. Halofantrine was equally active against chloroquine-sensitive and chloroquine-resistant isolates and was also active against pyrimethamine-resistant strains. Indications are that this drug would be suitable for the treatment of P. falciparum malaria in the southern African region.

Africa, Southern↗
PubMed1991

Drug treatment of experimental Capillaria hepatica infection in mice.

This report presents the results obtained using 14 anthelmintic compounds that were tested in experimental white mice of the Swiss-Webster strain for their action against Capilaria hepatica. Four of the drugs effectively prevented deposition of C. hepatica ova in mouse liver. The doses at which these four drugs prevented greater than 99% of egg deposition were: albendazole, 30 mg/kg; febantel, 30 mg/kg; mebendazole, 3.13 mg/kg; and oxfendazole, 12.5 mg/kg. Of these, mebendazole is the only agent for which the application of five daily doses of 3.13 mg/kg lay within the dose range recommended for man.

Albendazole↗