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Biomedical subjects

J Hay

Publications and source records attributed to J Hay.

At least 163 records · Page 9Linked to original sources
PubMed1989

An electron microscope and immunohistochemical study of the intracellular location of Toxoplasma tissue cysts within the brains of mice with congenital toxoplasmosis.

The wall of intact Toxoplasma tissue cysts within the brains of mice with congenital toxoplasmosis was investigated. Smaller cysts were identified within the soma of neurones. With larger cysts, the contained cystozoites were shown by ultrastructural examination to be surrounded by a layer of microtubules; immunohistochemical staining revealed that this layer contained neurofilament protein. Interior to this layer was a much convoluted parasitophorus vacuole membrane; exterior was the host cell membrane. In most cases, synaptic plates were noted on the outer plasma membrane. In no instance were tissue cysts observed either within neuroglial cells or in the absence of host cells. These observations are discussed in relation to the pathogenesis of congenital toxoplasmosis in the brain.

Animals↗
PubMed1988

Southern blot analysis of DNA extracted from formal-saline fixed and paraffin wax embedded tissue.

Model experiments were designed to assess whether DNA could be recovered from formol-saline fixed peripheral blood lymphocytes and tonsil tissue for use in Southern blot gene analysis. Lymphocytes were fixed for 30 min and tonsil for 6 and 24 h, then paraffin embedded. High molecular weight DNA was extracted by prolonged digestion (2-7 days) with proteinase K or protease XXIV in the presence of 1 per cent sodium dodecyl sulphate. Restriction, transfer and hydridization were possible without modification of standard procedures. Multiple copy sequences were demonstrated using Mspl and Bst Nl restriction and hybridization for the Y chromosome (pHY 2.1 probe), single copy genes using EcoRI and BamHl restriction for the T-cell receptor beta chain (T beta probe), and Bgl II and Hind III for the immunoglobulin heavy chain (JH probe). Identical banding to unfixed tissue was achieved except when 24 h fixed extracts were used. With these, demonstration of the 24 KB Bam Hl/T beta and 9.2 KB Hind III/JH bands was not obtained. These findings suggest that as the fixation time is extended, alterations to DNA will limit the available range of restriction enzyme/probe combinations. However, with careful choice of these the extraction of DNA from formalin fixed and paraffin embedded pathological tissue for Southern blotting should be profitable.

DNA↗
PubMed1988

Host-parasite relationship in the brains of mice with congenital toxoplasmosis.

The wall of intact tissue cysts in the brains of mice with congenital toxoplasmosis was investigated using light and electron microscopy. Impregnation of the wall with reduced silver salts and protargol silver suggested that it was composed, at least in part, of components derived from the neuronal cytoskeleton. Electron microscopy extended these observations and revealed that intact cysts were separated from the extracellular compartment by a layer of neurofibrillae enclosed within the host cell membrane. It is suggested that this may be a means whereby intact Toxoplasma tissue cysts are protected from the host's immune response.

Animals↗
PubMed1988

Effectiveness of a procedure for disinfecting the vaginal photoplethysmograph contaminated with herpes simplex virus type 2.

To test the effectiveness of a disinfecting procedure involving 2% glutaraldehyde, a vaginal photoplethysmograph was contaminated with a known amount of herpes simplex type 2 (HSV-2). The vaginal photoplethysmograph was then put through the disinfection procedure. Two virus solutions were tested, one designed to approximate the concentration found in a naturally occurring infection (low inoculum), the other with 100 times more virus (high inoculum). Varying lengths of exposure to glutaraldehyde were tested. Results of assays for the virus after the device was disinfected showed that no measurable infectious virus remained even at the shortest exposure to glutaraldehyde, 1 min. A second experiment was conducted in which glutaraldehyde was added directly to a virus solution. Results confirmed those of the first experiment.

Aldehydes↗
PubMed1988

Mutations in human lymphocytes studied by an HLA selection system.

Human lymphocytes mutated at the HLA-A2 or HLA-A3 alleles were enumerated and studied by primary selection using antibody and complement, followed by limiting dilution cloning and secondary selection using immunofluorescence or antibody and complement. The geometric mean frequency of in vivo mutant lymphocytes was 3.08 X 10(-5) for the HLA-A2 allele and 4.68 X 10(-6) for the HLA-A3 allele. Mutagenesis by X-radiation or mitomycin produced a dose-related increase in mutant frequency. HLA-B phenotyping and Southern Analysis of the HLA-A gene suggested that mutation was frequently due to gene deletion, which was often substantial.

Alleles↗
PubMed1988

Expression of the Hantaan virus M genome segment by using a vaccinia virus recombinant.

A cDNA containing the complete open reading frame of the Hantaan virus (HTN) M genome segment has been cloned into vaccinia virus. This recombinant virus expresses two glycoproteins which are similar to the HTN structural glycoproteins, G1 and G2, in molecular weight, cleavage pattern, and cellular distribution. Both HTN and recombinant vaccinia virus glycoproteins are exclusively associated with the Golgi apparatus of the cell. Despite this intracellular restriction, mice inoculated with the recombinant vaccinia virus raised neutralizing antibodies against HTN. The specificity of virus neutralization appears to reside in the HTN glycoproteins, since a vaccinia virus recombinant expressing the HTN nucleocapsid protein was unable to elicit a neutralizing antibody response.

Animals↗
PubMed1988

Identification and characterization of a varicella-zoster virus DNA-binding protein by using antisera directed against a predicted synthetic oligopeptide.

We have identified, in varicella-zoster virus (VZV)-infected cells, the product of the gene predicted to code for the VZV analog of the herpes simplex virus major DNA-binding protein. The open reading frame of the VZV gene has the potential to code for a protein with a predicted molecular weight of 132,000 (a 132K protein). To detect the protein, a 12-amino-acid oligopeptide corresponding to the carboxyl terminus of the putative open reading frame was synthesized and used to prepare antisera in rabbits. The resulting antibodies reacted specifically in Western immunoblot analysis and immunoprecipitation with a single 130K polypeptide found in VZV-infected cells. The specific reactivity of the antisera with the 130K polypeptide was inhibited by the addition of synthetic peptide. Immunofluorescence studies with the antisera as probe for the 130K polypeptide suggested that this peptide is located predominantly within the nuclei of infected cells. Analysis of proteins that bind to single-stranded DNA immobilized on cellulose matrices indicated that 30 to 50% of the 130K polypeptide is capable of interacting with single-stranded DNA and that this interaction is overcome with 0.5 M NaCl. Thus, we have prepared a specific polyclonal antiserum that identifies a VZV DNA-binding protein whose properties are similar to those of the herpes simplex virus ICP8 (Vmw130) DNA-binding protein.

Amino Acid Sequence↗
PubMed1987

Congenital neuro-ophthalmic toxoplasmosis in the mouse.

Clinical examination of the eyes of mice with congenital toxoplasmosis provided a good indication of the extent of underlying histopathological damage in the eye, but was of little value for predicting neuropathological severity. Furthermore, the dye-test titre was not related either to the degree of ocular damage or to the severity of brain damage.

Animals↗
PubMed1987

A high frequency of inherited deficiency of complement component C4 in Darwin Aborigines.

A high frequency of serum complement component C4A deficiency may explain the higher prevalence and greater severity of systemic lupus erythematosus reported in Australian Aborigines. Inherited deficiencies of serum complement components C4A, C4B, and C2 were examined in two Australian Aboriginal populations from Darwin and Alice Springs and compared with the prevalence of complement deficiencies in white Australian blood donors. The frequency of C4A deficiency alleles was 29% in Darwin Aborigines compared with 12% in Alice Springs and 17% in Canberra blood donors. Partial C4B deficiency was also higher in Darwin Aborigines than in the other populations. Inherited deficiency of serum complement component C2 was not observed.

Alleles↗
PubMed1986

The immunocytochemical demonstration of Toxoplasma antigen in the brains of congenitally infected mice.

The peroxidase anti-peroxidase immunocytochemical staining method was used to identify Toxoplasma antigen in paraffin embedded sections of the brains of 22 mice congenitally infected with the parasite. Intact Toxoplasma tissue cysts were readily demonstrated in the brain in all cases. In 4 of the 22 infected mice there was evidence of rupture of the cyst wall and/or presence of extra-cystic Toxoplasma antigen. Further support for the extra-cystic location of Toxoplasma antigen was obtained by electron microscopy of reprocessed tissue which revealed endozoites in the area immediately surrounding a ruptured cyst. The possible implications of these findings in relation to the pathogenesis of congenital toxoplasmic meningo-encephalitis are discussed.

Animals↗