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Biomedical subjects

M A Bayles

Publications and source records attributed to M A Bayles.

3 recordsLinked to original sources

Tropical mycoses.

The most common tropical subcutaneous and deep mycoses include chromomycosis, sporotrichosis and mycetoma. All are commonly found in Natal and in other subtropical countries. Although blastomycosis is endemic in North America, only 4 cases have been identified in Natal during the last 25 years, and all presented with atypical clinical features. African histoplasmosis, caused by Histoplasma capsulatum var. duboisii and limited mainly to central and western Africa, has been found in only 1 patient in Natal. Paracoccidioidomycosis, though the most common deep mycosis in Latin America, is limited to that area and there is no experience of this disease in South Africa. Over the past 8 years, itraconazole has been used in clinical trials for all 3 mycoses. The results in sporotrichosis, non-meningeal blastomycosis and paracoccidioidomycosis suggest that for these diseases itraconazole may be the drug of choice. The results in histoplasmosis are encouraging, as are the results in chromomycosis, particularly those cases associated with Cladosporium carrionii. Where Fonsecaea pedrosoi is the causal agent and in mycetomas, however, successful management still remains a therapeutic problem. Enhanced efficacy by combining flucytosine and itraconazole was seen in 3 patients. Even over prolonged periods, itraconazole has an impressive safety profile. In the present series of 41 patients, no side-effects were observed, no adverse reactions occurred, and serum chemistry values remained within normal limits. It appears, therefore, that itraconazole, though not the final answer to management of deep mycoses, is certainly a major improvement on previous drugs.

Adult

[Tropical mycoses].

The most common tropical subcutaneous and deep mycoses include chromomycosis, sporotrichosis and mycetoma. All are commonly found in Natal and in other sub-tropical countries. Although blastomycosis is endemic in North America, only four cases have been identified in Natal during the last 25 years and all presented with atypical clinical features. African histoplasmosis caused by H. capsulatum var. duboisii and limited mainly to central and western Africa has been found in only one patient in Natal. Paracoccidioidomycosis, although the most common deep mycosis in Latin America, is limited to that area and we have no experience of this disease in South Africa. Over the past eight years itraconazole has been used in clinical trials for all these mycoses. The results in sporotrichosis, non-meningeal blastomycosis and paracoccidioidomycosis suggest that for these diseases itraconazole may be the drug of choice. The results in histoplasmosis are encouraging as are the results in chromomycosis particularly those cases associated with C. carrionii. However, where F. pedrosoi is the causal agent and in mycetomas, successful management still remains a therapeutic problem. In our own experience and that of other using itraconazole, even over prolonged periods, this drug has an impressive safety profile. In our present series of 42 patients, no side effects were observed, no adverse reactions occurred and serum chemistry values remained within normal limits. It appears, therefore, that itraconazole, although not the final answer to management of the deep mycoses, is certainly a major improvement on previous drugs.

Antifungal Agents

Cutaneous reactions to topical application of hydroquinone. Results of a 6-year investigation.

The investigation was designed to assess the safety of hydroquinone in cosmetic skin-lightening products, and to determine the optimal concentration for the purpose. The 840 volunteers who took part in the 6-year trial were drawn from various race groups with skins varying from very fair to very dark. They were subjected to open tests, "normal usage" tests, and standard 48-hour closed-patch tests. In all, over 7,000 test areas were examined. The results show that concentrations of hydroquinone of 3% and less produced negligible adverse effects, irrespective of the base or the colour of the user's skin. It is stressed that any confusion of hydroquinone with the hazardous monobenzyl ether of of hydroquinone (monobenzone, MBH) should be avoided.

Administration, Topical