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Biomedical subjects

R J Hay

Publications and source records attributed to R J Hay.

At least 163 records · Page 9Linked to original sources
PubMed1990

Evidence that the M antigen of Histoplasma capsulatum var. capsulatum is a catalase which exhibits cross-reactivity with other dimorphic fungi.

A panel of monoclonal antibodies (Mabs) was raised against histoplasmin, the antigen derived from the mycelial phase of Histoplasma capsulatum var. capsulatum which contains the diagnostically useful H and M antigens. A number of Mabs were obtained which recognized a 70-75 kD component of an antigenic preparation of H. capsulatum var. capsulatum by Western blotting. When reacted with histoplasmin by Western blotting the Mabs recognized a similar 70-75 kD band, together with a series of higher molecular mass bands at approximately 130, 190 and 230 kD, a pattern which correlates strongly with both the published relative molecular mass (Mr) of the M antigen and the known subunit structure of the enzyme catalase. These Mabs were also shown to recognize a commercial preparation of Aspergillus niger catalase by ELISA. Other dimorphic fungi were also reactive with these Mabs by Western blotting, indicating the presence of common epitopes on the catalase molecules of these species.

Antibodies, Monoclonal↗
PubMed1989

Mycoplasma infection of cultured cells.

Mycoplasma contamination is tough to detect and even more difficult to eradicate. It is best to start over fresh from clean cell stocks, but several elimination options are available.

Animals↗
PubMed1989

In vitro adherence of Candida albicans strains to murine gastrointestinal mucosal cells and explants and the role of environmental pH.

Two in vitro adherence assays involving isolated mucosal cells or mucosal explants were used to study the adherence of five Candida albicans strains to murine gastrointestinal mucosal surfaces. Adherence was found to be dependent on the strain used, and on the cellular arrangement, as well as the site of origin of the mucosal surface. Adherence of strains NCPF 3436 and 3310 to stomach and jejunal surfaces was affected by the pH of the medium. Binding between the C. albicans strains and stomach mucosal cells fluctuated as the pH was raised from pH 1.2 to pH 3.4. However, adherence increased with a rise in pH when the strains were incubated with stomach mucosal explants. Optimal adherence by both strains to jejunal mucosal surfaces occurred at neutral pH.

Animals↗
PubMed1989

Onchodermatitis--correlation between skin disease and parasitic load in an endemic focus in Ecuador.

Onchocerciasis is a chronic parasitic infection in which infiltration of the skin by microfilariae has been associated with a number of different pathological changes. This survey compared the prevalence of different forms of skin disease in two villages, one of which was located within the endemic zone for onchocerciasis (Zapallo Grande), in a lowland rain forest area of western Ecuador. The commonest skin diseases in both villages were scabies, pyoderma and pityriasis versicolor. In addition changes closely correlated with the presence of microfilariae in skin snips were found in Zapallo Grande--such as atrophic gluteal changes, and acute and chronic papular dermatitis. The only other skin disease associated with onchocerciasis was widespread tinea corporis due to T. rubrum. The Amerindians in the endemic onchocerciasis area were more likely than Negroes to have generalized atrophic changes of the skin, whereas in the latter group significant numbers of individuals had no obvious skin lesions but large numbers of microfilariae were detected in skin snips. Acute papular dermatitis was common in both groups and in biopsied lesions microfilariae could usually be identified within the epidermis or close to the dermo-epidermal junction. One patient had developed severe reactive onchodermatitis (Sowda). Swabs taken from onchocercal skin lesions showed no evidence of skin surface carriage of Staphylococcus aureus. Changes classically associated with onchocerciasis such as pretibial hypopigmentation (leopard skin) and hanging groin were notably absent in this population.

Adolescent↗
PubMed1989

Fungal kerion--total scalp involvement due to Microsporum canis infection.

We report the case of a 5-year-old girl who developed a remarkably extensive kerion of the scalp due to Microsporum canis infection. Total scalp involvement of this severity and prolonged duration is now unusual, but there has been surprisingly little residual cicatricial alopecia. Microsporum canis does not respond well to ketoconazole, and griseofulvin remains the drug of choice for dermatophyte infections involving hair; a prolonged course may be necessary. This case also demonstrates the benefit of corticosteroids for certain cases of inflammatory ringworm where the host's response to the fungus is exceptionally marked.

Administration, Topical↗
PubMed1989

The diagnosis and management of tropical ulcer in east Sepik Province of Papua New Guinea.

This survey, carried out in the East Sepik Province of Papua New Guinea, examined the prevalence of tropical ulcer, the accuracy of diagnosis and the methods of management. Most patients presenting with ulcerative skin lesions are treated in acid posts (219) and an estimated 7500 cases are seen annually out of a total rural population of 260,000. A sample survey suggested that of these only two-thirds meet diagnostic criteria for tropical ulcer, the rest being 'sores' or infected traumatic lesions. Standard primary therapy for all such lesions usually includes intramuscular penicillin and regular dressings with Eusol. All patients are seen on at least four occasions and hospitalized patients require a minimum of 15 days therapy compared to 10 days if lesions are grafted early. Skin grafting produces excellent responses but has a high 'drop-out' rate. There is a clear need for a uniform approach to the management of ulcerated skin lesions combined with ready access to grafting facilities to reduce the need for long-term dressings and the risk of chronic ulcerations.

Bacterial Infections↗
PubMed1988

Tinea imbricata.

Explore the source record for details and available documents.

Animals↗
PubMed1988

The seed stock concept and quality control for cell lines.

Procedures for the characterization of cell culture lines are reviewed. It is recommended that seed stocks be developed and that major quality-control efforts be applied first to those holdings, with essential tests repeated on cultures from working or distribution stocks prepared subsequently. Steps are taken throughout to ensure absence of microbial contaminants. Mycoplasma are especially troublesome. Investigators need also to be aware of potential endogenous viruses which may be hazardous or interfere with interpretation of results. Cell line species and absolute identities are established by fluorescent antibody staining, by determination of isoenzyme profiles, and by cytogenetic analyses. Additional characterizations will vary with cell type but may include tests for specific products, cytoskeletal proteins, tissue specific antigens, or immunoglobulins. Credentials of lines added to a collection plus representative cultures can be returned to the originators for concurrence before distribution. Advisory committees may be established as circumstance dictates to provide additional expertise regarding quality control for the specific collection being developed.

Cell Line↗
PubMed1988

Humoral immune responses to mycetoma organisms: characterization of specific antibodies by the use of enzyme-linked immunosorbent assay and immunoblotting.

Levels of antibodies were determined by enzyme-linked immunosorbent assay (ELISA) in 13 patients with eumycetomas due to Madurella mycetomatis infections. Raised levels of specific IgM were observed in 12 patients, compared with normal human controls. By contrast, low levels of specific IgG were detected in some patients. Specific responses to separated protein antigens were investigated by immunoblotting. Of 10 patients' sera tested, IgM in 2 recognized up to 7 of the blotted antigens between 45 and 84 kDa. Gold-labelled protein A (which predominantly binds to IgG) indicated that sera from 2 patients reacted with at least 6 protein bands with relative molecular masses between 64 and 95. The demonstration of significant IgM levels by ELISA, but few antigenic bands in sera from the same patients by immunoblotting, may point to an antibody response against polysaccharide fungal antigens in mycetoma patients. The use of the ELISA to detect antibodies of different classes and the characterization of their antigenic specificities by immunoblotting may have both diagnostic and prognostic value.

Animals↗
PubMed1988

Candida onychomycosis--an evaluation of the role of Candida species in nail disease.

Nail infections caused by Candida species are normally associated with chronic paronychia or chronic mucocutaneous candidiasis (CMCC). However, the role of Candida in the pathogenesis of other primary nail dystrophies has been questioned in view of their response to antifungal therapy alone. In the present study of 86 patients with primary nail dystrophies from which Candida was isolated, three patterns of nail involvement were found. Nineteen patients, of whom 17 had CMCC, had total dystrophic onychomycosis of at least two nails. The second group consisted of 27 patients with paronychia and lateral onycholysis. In a further 40 patients, who did not have paronychia, Candida was isolated from nails showing primary distal and lateral onycholysis. These changes were mainly seen in patients with peripheral vascular disease, particularly Raynaud's disease, or Cushing's syndrome. Nail biopsies from patients in the latter two groups confirmed the presence of yeasts and mycelium in the nail plate and 17 (46%) of those receiving antifungal therapy with ketoconazole or itraconazole showed complete clearance of the nail dystrophy. Good responses to therapy were seen more frequently in patients with peripheral vascular disease or Cushing's syndrome of whom 15 (72%) recovered; distal erosion of the nail plate, mycelium in the nail plate on biopsy or direct microscopy together with the isolation of C. albicans were all associated with good responses to antifungals. In addition to patients with CMCC or paronychia, therefore, Candida appears to be a significant pathogen in some patients with primary onycholysis of the finger nails, particularly where there is underlying peripheral vascular disease or Cushing's syndrome.

Adolescent↗
PubMed1988

An evaluation of itraconazole in the management of onychomycosis.

At present the reported use of itraconazole, a new oral triazole antifungal, has been confined to short-term treatments. This investigation is an appraisal of itraconazole in the treatment of three different forms of onychomycosis. Six patients with nail infections due to Candida albicans not associated with paronychia affecting a total of 20 nails received itraconazole (100 mg daily) for a mean period of 5.9 months. Complete remission was achieved in all cases. Twenty six patients with dermatophyte onychomycosis affecting a total of 45 finger and 80 toe-nails were treated with itraconazole (100-200 mg daily). In 24 cases the causative organism was Trichophyton rubrum. Remission was achieved in 64% of finger and 73% of toe-nails in 5 and 9.4 months, respectively. Treatment failures were experienced in patients with finger-nail infections due to T. violaceum (I) and those concurrently receiving phenytoin and phenobarbitone (3). Three patients with infections due to Hendersonula toruloidea failed to respond to treatment. Adverse effects were experienced by four patients (abdominal discomfort 3, diarrhoea I), but none were serious enough to lead to abandonment of treatment. No persistent changes were seen in serum biochemical values. This study suggests that itraconazole is potentially effective in the long-term treatment of superficial fungal infections such as onychomycosis, and comparative studies with alternatives such as griseofulvin should now be carried out.

Adult↗