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Biomedical subjects

R J Hay

Publications and source records attributed to R J Hay.

At least 55 records · Page 3Linked to original sources
PubMed1999

Detection of the 70-kilodalton histoplasma capsulatum antigen in serum of histoplasmosis patients: correlation between antigenemia and therapy during follow-up.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals, who may develop a progressive disseminated form which is often fatal if it is untreated. In such patients, the detection of antibody responses for both diagnosis and follow-up may be of limited use, whereas the detection of Histoplasma capsulatum var. capsulatum antigens may provide a more practical approach. We have recently described an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection in patients' sera of a 69- to 70-kDa H. capsulatum var. capsulatum-specific antigen which appears to be useful in diagnosis. To investigate its potential for the follow-up of histoplasmosis patients during treatment, antigen titers in the sera of 16 patients presenting with different clinical forms of histoplasmosis were monitored at regular intervals for up to 80 weeks. Sera from four of five patients with the acute form of the disease showed rapid falls in antigenemia, becoming antigen negative by week 14 (range, weeks 10 to 16). Sera from four patients with disseminated histoplasmosis showed falls in antigen levels; three of them became antigen negative by week 32; the fourth patient became negative by week 48. In contrast, antigen titers in four of six AIDS patients with the disseminated form of the disease remained positive throughout follow-up. Sera from only one patient who presented with the chronic form of the disease were analyzed, and this individual's serum became antigen negative by week 9. The inhibition ELISA is shown to be of particular use in the monitoring of non-AIDS patients with the acute and disseminated forms of the disease and may complement existing means of follow-up.

AIDS-Related Opportunistic Infections↗
PubMed1999

Production of specific monoclonal antibodies to Aspergillus species and their use in immunohistochemical identification of aspergillosis.

Two anti-Aspergillus murine monoclonal antibodies (MAbs), designated 164G and 611F, have been produced; both specifically recognize cytoplasmic antigens of A. fumigatus, A. flavus, and A. niger by enzyme-linked immunosorbent assay. The MAbs can identify Aspergillus spp. both in frozen sections by immunofluorescence and in paraffin-embedded clinical specimens by immunofluorescence and immunoperoxidase staining.

Animals↗
PubMed1998

Cell line availability: where to get the cell lines you need.

The availability and utility of cell lines with limited and continuous doubling potential are summarized and documented. Reference to national cell banks is included with pertinent and current contact information. The continuing need for vigorous application of quality control procedures is emphasized with data illustrating frequencies of microbial infection in cultured cell lines as well as high incidences of cross-contamination of one cell line with another.

Animals↗
PubMed1998

Overview of matrix metalloproteinase expression in cultured human cells.

The matrix metalloproteinases (MMP) have been implicated in tumor invasion and metastasis both by immunohistochemical studies and from the observation that specific metalloproteinase inhibitors block tumor invasion and metastasis. Oligonucleotide primers for thirteen MMPs (MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-11, MMP-12, MMP-13, MMP-14, MMP-15, MMP-16) were optimized for use in RT-PCR. A semi-quantitative RT-PCR assay was used to determine the pattern of MMP mRNA expression in 84 normal and transformed or carcinogen transformed human cell lines and strains derived from different tissues. The results demonstrate one or more cell lines which express thirteen members of the MMP family. In addition, various oncogene transfected human fibroblast cell strains were analyzed for MMP expression. We confirm that over-expression of the H-ras oncoprotein correlates with up-regulation of MMP-9 and demonstrate that over-expression of v-sis also up-regulates MMP-9. A cell line immortalized following myc expression was found to up-regulate MMP-7, MMP-11 and MMP-13. Inappropriate expression of several MMP mRNAs was detected in breast, prostate, bone, colon and oral tumor derived cell lines. Identification of at least one cell line expressing each of thirteen MMPs and the observation of oncogene induced expression of several MMPs should facilitate analysis of the transcriptional mechanisms controlling each MMP.

Cell Line↗
PubMed1998

Cutaneous infection with Alternaria alternata complicating immunosuppression: successful treatment with itraconazole.

We report an immunosuppressed patient who presented with unusual leg ulceration caused by Alternaria alternata infection. Alternaria is a common saprophyte that is not usually pathogenic in humans. However, infections have previously been documented. Most cases occur in immunocompromised patients and the skin manifestations may vary considerably. The diagnosis is often missed initially as it is not frequently suspected. The treatment is controversial both in choice of agent used and in duration of therapy.

Aged↗
PubMed1998

A new classification of onychomycosis.

This new classification of onychomycosis is a development of previous schemes and depends on the recognition of different clinical patterns of nail plate involvement associated with fungal infection as well as histopathology. The main types are distal and lateral subungual onychomycosis, superficial onychomycosis, proximal subungual onychomycosis, endonyx onychomycosis and total dystrophic onychomycosis. In addition, patients may show different combinations of these patterns. The identification of clinical patterns of disease may be useful in defining differences in clinical behaviour, treatment response and associated disease.

Acremonium↗
PubMed1998

Dermatology in southwestern Ethiopia: rationale for a community approach.

BACKGROUND: Skin diseases represent one of the most frequent causes of morbidity in developing countries; however, little is known about the dermatologic needs of the population. The prevalence of skin disease in two different rural communities in southwestern Ethiopia was determined using descriptive epidemiologic techniques. METHODS: A household survey, designed to ascertain demographic information and dermatologic needs, was given to all households in both communities (827). The point prevalence of skin diseases was determined after examination by dermatologists of 768 self-selected individuals (40% of individuals were invited to attend dermatologic examination, either those self-reporting skin disease or identified as positive cases during the household survey); an individual survey form was given to all of these patients. RESULTS: Although 47% (S/UO) and 59% (Kishe) of the households in the two communities reported skin symptoms, the true dermatologic needs of these settlements were far greater than the expressed values, as examination by dermatologists of randomly selected households revealed that 67% of householders not reporting dermatoses had significant skin disease. During the point prevalence study, the commonest complaints were parasitic (scabies, pediculosis, and onchocerciasis) infestations (46% of diagnoses), followed by bacterial and fungal infections (33%); other conditions included endemic nonfilarial elephantiasis. Overcrowding was the main risk factor for infection. Thirty-two per cent (S/UO) and 39% (Kishe) of examined individuals had received previous treatments, which were ineffective in 74% and 63% respectively. CONCLUSIONS: Subsistence farmers spend a high proportion of their limited cash income on ineffective treatment. Simple schemes of management for the most common dermatoses, which local health workers could be trained to recognize and manage, could do much to redress the burden of skin disease in this population.

Adolescent↗
PubMed1998

Synergy of antibiotics against Streptomyces somaliensis isolates in vitro.

Eight dual antibiotic combinations were used to investigate possible synergic effects against different isolates of Streptomyces somaliensis. The antibiotic combinations that showed synergic activity against the isolates were, in decreasing order, fusidic acid-rifampicin, erythromycin-penicillin, erythromycin-fusidic acid, rifampicin-sulphamethoxazole, fusidic acid-sulphamethoxazole and erythromycin-rifampicin. Sulphamethoxazole-trimethoprim and rifampicin-trimethoprim combinations were not synergic against any of the S. somaliensis isolates tested.

Drug Therapy, Combination↗
PubMed1998

Sialic acid-dependent recognition of laminin by Penicillium marneffei conidia.

Immunofluorescence microscopy demonstrated that laminin bound to the surface of Penicillium marneffei conidia. Attachment of P. marneffei conidia in an adherence assay was inhibited by soluble laminin and anti-laminin antibody. N-Acetylneuraminic acid abolished adherence, indicating an interaction mediated by a sialic acid-specific lectin.

Cell Adhesion↗
PubMed1998

Antigenemia in patients with paracoccidioidomycosis: detection of the 87-kilodalton determinant during and after antifungal therapy.

Serological diagnosis and follow-up of paracoccidioidomycosis (PCM) patients have relied mainly on the detection of antibody responses by using techniques such as complement fixation (CF) and immunodiffusion. We recently described a novel inhibition enzyme-linked immunosorbent assay (inh-ELISA) which proved to be useful in the diagnosis of PCM via the detection of an 87-kDa determinant in patient sera (B. L. Gomez, J. I. Figueroa, A. J. Hamilton, B. Ortiz, M. A. Robledo, R. J. Hay, and A. Restrepo, J. Clin. Microbiol. 35:3278-3283, 1997). This test has now been assessed as a means of following up PCM patients. A total of 24 PCM patients, classified according to their clinical presentation (6 with the acute form of the disease, of whom two had AIDS, 12 with the multifocal form of the disease, and 6 with the unifocal form of the disease), were studied. The four human immunodeficiency virus-negative patients with acute PCM showed a statistically significant decrease in circulating antigen levels after the start of antifungal therapy. Antigen levels in this group became negative by our criteria (</=2.3 microgram/ml) before week 20 and remained so in three of four of these patients. In contrast, the two AIDS patients who also presented with the acute form of PCM showed no statistically significant decrease in circulating antigen levels even after 68 weeks of therapy. Taken together as a group, the patients with the multifocal form showed a statistically significant decrease in antigenemia after 28 weeks of therapy. In addition, five of six patients with the unifocal form became antigen negative by week 40. Antigen level decrease mirrored clinical cure in the majority of patients in all clinical groups; in contrast, measurement of anti-PCM antibodies via the CF test showed wide fluctuations in titers during the follow-up period. The inh-ELISA for the detection of the 87-kDa Paracoccidioides brasiliensis determinant would appear to be a valuable additional tool in the follow-up of PCM patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Identification and purification of specific Penicillium marneffei antigens and their recognition by human immune sera.

Disseminated infection with the dimorphic pathogenic fungus Penicillium marneffei is increasingly seen among patients with AIDS in southeast Asian countries. Previous studies have demonstrated the presence of humoral immune responses to this fungus in patient sera; we have confirmed this work using sera from P. marneffei-infected patients (n = 21) to develop Western blots of P. marneffei cytoplasmic yeast antigen (CYA). P. marneffei CYA was then partially purified by liquid isoelectric focusing, and fractions were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Immunoenzyme development of the Western blots with pooled sera from patients with P. marneffei infection and with pooled sera from patients with aspergillosis (n = 20), candidiasis (n = 10), cryptococcosis (n = 9), and histoplasmosis (n = 11) revealed three antigens with relative molecular masses of 61, 54, and 50 kDa. These antigens were specifically recognized by the pooled sera from the P. marneffei-infected patients. The 61- and 54-kDa antigens were subsequently purified to homogeneity by preparative gel electrophoresis, and the 50-kDa antigen was partially purified by the same technique. N-terminal amino acid sequencing revealed that the 61-kDa antigen had a strong homology (87% identity) with the antioxidant enzyme catalase. The three antigens were then subjected to SDS-PAGE and Western blotting and to immunoenzyme development with individual patient sera; sera from 86% of P. marneffei-infected patients recognized the 61-kDa antigen, sera from 71% recognized the 54-kDa antigen, and sera from 48% recognized the 50-kDa antigen. These specifically recognized antigens are the first to be purified from P. marneffei and can be used either singly or in combination to detect antibody responses in a large percentage of individuals infected with P. marneffei.

Antigens, Fungal↗
PubMed1997

Identity of original and late passage Dami megakaryocytes with HEL erythroleukemia cells shown by combined cytogenetics and DNA fingerprinting.

During routine authentication checks, we noticed untoward karyotypic similarities between late-passage stocks of the Dami megakaryocyte and HEL erythroleukemia cell lines. Genetic identity of Dami with HEL was demonstrated by DNA fingerprinting with a (gtg)5 multilocus probe and confirmed for earlier passages of Dami deposited by its originators with the ATCC. As initial passage stocks of Dami are no longer available for comparison, we investigated whether cross-contamination by HEL was more likely to have occurred during Dami's establishment or subsequently, by karyotyping currently available stocks of both cell lines for comparison with that originally reported for Dami. We found that the karyotype of current stocks of Dami overwhelmingly resembles that described in the original report, having retained at least 16/18 structural chromosome rearrangements as described therein, cf. 12/20 shared by current stocks of Dami and HEL. HEL's antecedence is shown by the retention of normal homologs of chromosomes, 6, 18, and 21--all rearranged in Dami. These results confirm the identity of current and early passage stocks of Dami and their common origin by cross-contamination with HEL which had occurred by July 1987, a year prior to publication. Thus, most, if not all, studies using Dami are likely to have employed HEL instead and may require reappraisal.

Chromosome Aberrations↗