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Biomedical subjects

R J Hay

Publications and source records attributed to R J Hay.

At least 19 recordsLinked to original sources
PubMed1992

Genetic susceptibility to dermatophytosis.

Clustering of cases of dermatophytosis suggests that inherited susceptibility may play a part in determining the epidemiology of some forms of this infection, notably tinea imbricata. Some studies of T. concentricum infection show that autosomal recessive susceptibility may provide an answer although this is not the case in all endemic areas. Further support comes from the association between dermatophytosis in man and inherited conditions such as atopy, chronic mucocutaneous candidosis and tylosis as well as experimental data showing that susceptibility to dermatophytosis in mice varies in different inbred strains. Possible mechanisms are discussed.

Adolescent↗
PubMed1992

Nomenclature of fungal diseases: a report and recommendations from a Sub-Committee of the International Society for Human and Animal Mycology (ISHAM).

The ISHAM Mycoses Nomenclature Committee has considered the present status of fungal disease names. It suggests that the traditional approach to mycoses nomenclature in which the name of a causative taxon is suffixed with '-asis', '-iasis', '-osis' or '-mycosis' leads to names that are frequently unstable with respect to subsequent taxonomic and clinico-epidemiological changes. It is therefore recommended that individual mycoses should be named as often as possible in the form 'pathology A due to/caused by fungus X' or '[adjectival] fungus X pathology A' in preference to construction of names based solely on fungal taxa. A list of recommended mycosis names retained for their long tradition or intrinsic convenience is provided, together with a combined index and list of rejected names.

Animals↗
PubMed1992

Mycetoma.

Explore the source record for details and available documents.

Humans↗
PubMed1992

Possible mechanisms of immune modulation in chronic dermatophytoses: an in vitro study.

It has been suggested that patients with chronic superficial Trichophyton rubrum infection have defective cellular immunity to dermatophyte antigens. This may be due to a selective anergy to dermatophyte antigens or reflect the activity of dermatophyte-derived lymphocyte inhibitory factors. To explore these possibilities, we assessed lymphocyte transformation to a variety of recall antigens, including a cytoplasmic and exoantigen preparation of Trichophyton rubrum in 15 patients with chronic dermatophyte infection and 15 age- and sex-matched positive controls. In a duplicate set of experiments, autologous serum was replaced by heat-inactivated fetal calf serum. In addition, the direct effect of Trichophyton rubrum extracts on lymphoproliferation was assessed in vitro. Comparable lymphocyte transformation to each recall antigen was observed in patients and controls. Moreover, we found no evidence for a circulating dermatophyte-derived lymphocyte inhibitory factor in sera from patients with chronic superficial infection. A direct inhibitory effect of Trichophyton rubrum on lymphocyte proliferation to recall antigens was observed, however, at protein concentrations of > 10 micrograms/ml (exoantigen preparation) and > 25 micrograms/ml (cytoplasmic preparation). This inhibitory effect was rapidly reversible, not associated with loss of cell viability and maximal when added within 24 h of antigen to cultured lymphocytes. Class II MHC antigen HLA-DR, a surface marker of T-cell activation, was observed on inhibited lymphocytes co-cultured with antigen, suggesting the primary target for the inhibitory effect in vitro is the lymphocyte rather than the antigen-presenting cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Treatment of dermatomycoses and onychomycoses--state of the art.

We have reached a stage whereby many of the superficial mycoses are treatable with short courses of antifungal drugs. However, the minimum duration of therapy has still not been well defined and there remain some mycoses which do not respond to conventional therapy. It may be possible to introduce more radical approaches to therapy such as the single-dose oral or topical therapy for tinea pedis or short-duration therapy for onychomycosis. Amongst these options, topical therapies still have a part to play in the management of onychomycosis, and the role of amorolfine in this respect is of potential value. The ability of the drug to produce lasting remissions after short courses of treatment is also of great interest. Last, but not least, amorolfine has an in-vitro spectrum of activity which covers some of the less common cutaneous pathogens, and hence it may prove of benefit in those infections for which treatment at present is limited.

Antifungal Agents↗
PubMed1992

A 34- to 38-kilodalton Cryptococcus neoformans glycoprotein produced as an exoantigen bearing a glycosylated species-specific epitope.

Three monoclonal antibodies (MAbs), all of the immunoglobulin G1 subclass, were raised against Cryptococcus neoformans by using the technique of cyclophosphamide ablation of B-cell responses against shared epitopes of the cross-reactive fungus Trichosporon beigelii. MAb 3C2 was reactive against the encapsulated and nonencapsulated isolates of C. neoformans var. neoformans by enzyme-linked immunosorbent assay (ELISA) and Western blot (immunoblot), and in addition to a 34- to 38-kDa determinant, it recognized a series of lower-molecular-weight species. 3C2 also reacted strongly with culture supernatant preparations of C. neoformans var. neoformans by ELISA. 3C2 showed no recognition of either T. beigelii or C. neoformans var. gattii antigens. Enzymatic deglycosylation followed by reaction with 3C2 on Western blots revealed that sialic acid was an integral part of the determinant, together with N-acetylglucosaminyl-asparagine and alpha-mannose. Proteolytic digestion showed that the epitope was pepsin sensitive and that it also contained tryptophan and glycine and/or leucine as determinants of recognition by 3C2. The pI of the glycoprotein was 7.1. Affinity chromatography-purified antigen did not exhibit proteolytic activity on sodium dodecyl sulfate-polyacrylamide substrate gels. Indirect fluorescence antibody tests revealed that 3C2 labelling was confined to the cell membrane and cytoplasm of yeasts. The remaining MAbs, 7H4 and 5G5, recognized both capsulated and nonencapsulated strains of C. neoformans var. neoformans by both ELISA and Western Blot, identifying linear determinants with molecular masses of 36 and 30 kDa. They were unreactive against culture supernatant antigen (exoantigen) from either variant of C. neoformans.

Animals↗
PubMed1992

Methods for authenticating cell lines.

Methods for authentication of cell lines include tests for microbial contamination, verification of the species of origin, documentation of particular characteristics or functions and the absolute identification of individual cell lines. Experience indicates that mycoplasma contamination is still a serious problem in the cell culture field, with estimates on frequencies of infection varying from 10% upwards. The utilization of pre-screened reagents and antibiotic-free cultivation, plus the application of improved procedures, such as fluorescent dyes and molecular probes for detection, provide effective means to avoid mycoplasma infection and facilitate control. Viral contamination is perhaps more problematic, especially where no overt cytopathic effect results. The potential exists for the introduction of viruses from the cell culture technician or reagents used. Representative problem viruses are listed with standard procedures for screening. Detailed studies on animal cell cross contaminations have been performed and published. The frequency of detection of problem culture varied from 17-36% in studies performed in the USA. Both interspecies and intraspecies contaminations have been involved. Awareness of the potential for this problem plus the application of several characterization procedures are key factors for control. For example, fluorescent antibody staining, iso-enzyme analysis, cytogenetic evaluation and DNA finger-printing using molecular probes are needed for quality assurance on seed stocks. The critical importance of generating well-characterized reference cell stocks for use over the years is emphasized.

Animals↗
PubMed1991

A comparative study of terbinafine versus griseofulvin in 'dry-type' dermatophyte infections.

We conducted a double-blind comparative study of terbinafine, 250 mg twice daily, versus griseofulvin, 500 mg twice daily, for 6 weeks in chronic dermatophyte infections of the feet or hands. All but three patients (total 31) had Trichophyton rubrum infection. At 12-week follow-up, 100% of the terbinafine-treated group were free from infection compared with 45% of those treated with griseofulvin. Therapy in 75% of the terbinafine-treated group and in 35% of those given griseofulvin was rated as effective overall at long-term follow-up, although these differences were not statistically significant. Six months after treatment all nine patients whose skin had cleared with terbinafine therapy remained in remission versus only one of seven patients treated with griseofulvin. None of the patients in either group experienced serious adverse effects.

Antifungal Agents↗
PubMed1991

The role of chemoprophylaxis in the prevention of airborne infection by fungal pathogens.

The main approach to prevention of infection following airborne transmission of pathogenic fungi such as Aspergillus species has been environmental. However, there are a number of potentially effective methods of prophylaxis using antifungal drugs. Those described previously include itraconazole or amphotericin B given by the intranasal or intrapulmonary route after nebulization. Another possibility for investigation in the future is enilconazole which is highly active against aspergilli after inhalation in animals and which has been used in the treatment of aspergillosis in poultry.

Air Microbiology↗
PubMed1991

Antifungal therapy and the new azole compounds.

At present there are weaknesses in the range and scope of antifungal chemotherapy. The development of a new group of azole drugs, the triazoles, has introduced antifungal agents with broad-spectrum activity which can be given by the oral route. Fluconazole is very well absorbed and has good penetration. While its principal activity is against yeasts and there are clinical data to support its use in candida and cryptococcus infections, little work has been completed on its clinical use in aspergillosis. Itraconazole is less well absorbed, but highly bound in tissue. Its spectrum of activity is somewhat broader than that of fluconazole and it is clinically active against superficial mycoses and some of the infections caused by pathogenic fungi such as Histoplasma capsulatum. There is some early evidence of efficacy in aspergillosis but more studies are required in neutropenic patients. Both drugs show promise but comparative assessments are sorely needed.

Animals↗
PubMed1991

Overview of the treatment of disseminated fungal infections.

Disseminated fungal infections are significant causes of mortality and morbidity in the immunocompromised patient. There is now an increasing array of drugs available for their treatment. While amphotericin B is still the main choice for many of these infections the imidazole and triazole drugs have specific roles to play in the management of these patients. However, there remain a number of important problems, particularly the treatment of the patients with continuing immunosuppression and the emergence of antifungal drug resistance. There are also too few comparative studies of drugs within the increasing number of antifungal agents which would provide a reliable basis for choice.

Animals↗
PubMed1991

Cutaneous Mycobacterium kansasii infection--treatment with erythromycin.

A 20-year-old woman developed cutaneous Mycobacterium kansasii infection following steroid infiltration of two plaques of lichen simplex. The organism was resistant to many standard antituberculous drugs and following sensitivity studies treatment with erythromycin was begun. This has been effective and well tolerated. Treatment of atypical mycobacteria with drugs not traditionally associated with antituberculous activity is being increasingly reported and, so far, resistance has not been a problem. Erythromycin has good tissue penetration with excellent activity against M. kansasii and should be considered in the therapy of similar cases.

Adult↗