Trichophyton mentagrophytes spores differ from mycelia in their ability to induce pustules and activate complement.

To determine whether the morphology of dermatophytes plays a role in the clinical manifestation of dermatophytosis, we isolated spores and mycelia from colonies of killed Trichophyton mentagrophytes and tested their ability to induce gross and microscopic cutaneous changes when applied to guinea pig skin. The skin of normal guinea pigs failed to develop any cutaneous changes after inoculation with either dead spores or mycelia. In contrast, guinea pigs that had recovered from a T. mentagrophytes infection reacted to topically applied spores by producing pustules but failed to develop pustules either grossly or microscopically when inoculated with mycelia. Because differences in the activation of C' and the subsequent generation of the polymorphonuclear leukocyte (PMN) chemoattractant, C5a, might account for our in vivo findings, we measured the amount of C5a activated in vitro when serum was incubated with equivalent amounts of spores or mycelia. Spores consistently activated more C' to C5a than mycelia, although each could activate serum C'. The results support previous studies that show a direct correlation between the clinical manifestations of a dermatophytic infection and the development of immunity against the dermatophyte. Furthermore, the data suggest that a dermatophyte's predominant morphology during an infection may play a critical role in producing pustules by activating C' and chemoattracting PMNs into the fungus-laden stratum corneum.

Nutritional deficiencies in the neonate.

This article reviews common nutritional deficiencies that have been identified in newborn infants, including deficiencies of protein; vitamins A, D, K, C, and E; calcium and phosphorus; folate; zinc; and copper. The etiology, clinical presentation, diagnosis, and treatment of these nutritional deficiencies are discussed.

Interaction between thermal environments and hormones affecting skin-shedding frequency in the tokay (Gekko gecko) (Gekkonidae, Lacertilia).

Effects of thyroidectomy and/or hypophysectomy on the skin-shedding frequency (SF) in the tokay Gekko gecko and of thyroid hormones on the oxygen consumption (OCR) at various temperature regimes have been determined. Surgery invariably protracted the cycle length, thus decreasing SF; the extent of these changes was temperature dependent, the higher the temperature, the less the difference. Effects of hypophysectomy on cycle length were expressed in two phases; an extended first post-operative cycle was followed by a further extended second post-operative cycle, with cycle length forming a plateau thereafter. With time, the operated tokays would die without shedding during a greatly protracted cycle. OCRs in the tokay were temperature dependent, but between 28 and 34 degrees C, no significant difference could be seen. Effects of thyroid hormones on OCR were also temperature dependent. Furthermore, tokays having higher OCR were shown to have shorter cycles and vice versa. Results showed that whatever effect hormone(s) have on SF is indirect through general metabolic changes. SF is merely a reflection of the general metabolic status of the animal. It is proposed that the role of hormone(s), those of the thyroid in particular, is to act as "fine-tuning" devices in the regulation of metabolism and, as such, of the viability of the animal.

Alcohol-dependent liver cell necrosis in vitro: a new model.

In alcoholic liver injury, necrosis is involved in the progression from benign fatty liver to alcoholic hepatitis and cirrhosis. However, there is no practical model of alcohol-dependent liver cell necrosis. The calcium-dependent killing of cultured rat hepatocytes by two different membrane-active hepatotoxins, galactosamine and phalloidin, is potentiated by ethyl alcohol. This indicates that some general physical effect of alcohol on cellular membranes renders cells susceptible to otherwise nonlethal injuries. The in vitro model described in this report may thus be used to search for a general mechanism underlying alcohol-related tissue injury.

Epidermal regeneration and percutaneous water loss following cellophane stripping of reptile epidermis.

The histological and physiological effects of the removal of superficial corneous epidermal materials have been studied in several squamate species and a caiman. The gross and microscopic anatomy of the squamate integument has characteristics which make cellophane stripping inherently variable, but in general, when corneous materials were removed, they are replaced over a period of one to two weeks, by a tissue with the histological characteristics of the normal alpha-layer. This tissue may be produced by stimulated germinal activity and/or metaplasia of the other presumptive cell populations. In caiman, the thickness of the corneous tissues of the outer scale surface is reduced by stripping and the tissue is restored to normal in approximately two weeks by stimulated germinal proliferation. Measurements of cutaneous water loss (CWL) before, immediately after, and during two weeks post-trauma revealed the following. There is a sudden rise in CWL immediately after stripping, and values decline over the next two weeks as the corneous tissues are replaced. The results are interpreted as indicating that, as in mammals, the impermeability of the epidermis depends on the thickness of the corneous materials. In squamates it appears that the physiological barrier is the alpha-layer of the epidermal generation, and while the beta-layer cannot be excluded as playing some role in reducing the permeability of the integument, its role appears to be primarily mechanical.