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Biomedical subjects

J Hay

Publications and source records attributed to J Hay.

At least 127 records · Page 7Linked to original sources
PubMed1992

The management of carcinoma of the anal canal by external beam radiotherapy, experience in Vancouver 1971-1988.

From 1971 to 1988 72 cases of carcinoma of the anal canal were treated by external beam radiotherapy, most commonly by 5000 cGy in 20 fractions given over 4 weeks. The actuarial survival at 5 years was 66% and the disease specific survival 78%. Nine patients had inguinal node metastases at diagnosis; their 5-year disease specific survival was 75%. 63 patients were inguinal node negative at presentation; their 5-year disease specific survival was 78%, by UICC 1987 staging: T1 71%, T2 88%, T3 41%, T4 42%. 17 patients developed local recurrence; 10 were suitable for abdominoperineal (AP) resection which was successful in 7. The probability of local control was related to T stage. 13 patients were left with a colostomy because of recurrence, 2 had a colostomy for radiation damage and 4 had their local recurrence managed palliatively, without a colostomy. As a result, 53 of the 72 patients (74%) were left with a functional anus. Severe late complications occurred in 6 (8%).

Aged↗
PubMed1992

Treatment of antineutrophil cytoplasmic autoantibody-positive systemic vasculitis and glomerulonephritis with pooled intravenous gammaglobulin.

Antineutrophil cytoplasmic autoantibody (ANCA) is considered a serological marker for disease activity in patients with ANCA(+) systemic vasculitis. Recently, ANCA has been implicated as a pathogenic antibody that may be associated with neutrophil degranulation and release of lytic enzymes. Since intravenous gammaglobulin (IVIG) is known to contain antiidiotypic antibodies to ANCA, which could decrease the activity of the later, we chose to treat two patients with symptomatic ANCA(+) systemic vasculitis and glomerulonephritis with high-dose IVIG. The first patient, a 66-year-old man, developed rapidly progressive renal failure despite treatment with intravenous (IV) cyclophosphamide. The second patient, a 14-year-old boy, had relapsed 3 months after cessation of treatment with prednisone and cyclophosphamide. Both patients improved dramatically after treatment with IVIG, with the former recovering renal function within 11 days of therapy. In both patients, a concomitant reduction in serum ANCA titers was also observed. The second patient is currently in a sustained remission 14 months after his last IVIG dose on no other medication. These cases provide clinical evidence that IVIG has therapeutic benefit in modifying the immune-mediated injury associated with ANCA(+) systemic vasculitis and glomerulonephritis. In addition, IVIG may provide an additional safe therapeutic option to clinicians treating patient's with ANCA(+) vasculitis and glomerulonephritis who are not responsive to or are experiencing toxicity from conventional therapy.

Adolescent↗
PubMed1992

Kinetics and viral protein specificity of the cytotoxic T lymphocyte response in healthy adults immunized with live attenuated varicella vaccine.

The cytotoxic T lymphocyte (CTL) response was evaluated in adults given live attenuated varicella vaccine, using target cells expressing varicella-zoster virus (VZV) immediate-early protein (IE62) or VZV glycoproteins gpI, gpIV, or gpV to determine viral protein specificity. The frequency of CTL that recognized IE62 was 1:171,000 +/- 46,000 SE in subjects tested 10 days to 8 weeks after the initial vaccine dose; the induction of CTL specific for gpI was equivalent. CTL recognition of VZV proteins was mediated by CD4+ or CD8+ cells. CTL recognition of IE62 and gpIV persisted in vaccinees (tested approximately 4 years later) and was comparable to that in the naturally immune. The mean frequency of CTL specific for gpV was lower (but not significantly) in vaccinees than in naturally immune subjects. Assay of responder cell frequencies showed persistence of equivalent numbers of T lymphocytes that recognized IE62 and gpI in vaccinees and naturally immune subjects. Immunization with this vaccine elicited memory T lymphocyte responses to VZV comparable to those induced by natural infection.

Antibodies, Viral↗
PubMed1992

An investigation of the contribution of the extraosseous tissues to the diaphyseal fracture callus using a rabbit tibial fracture model and in situ immunocytochemical localisation of osteocalcin.

The extraosseous tissue contribution to diaphyseal fracture callus has been investigated using a rabbit tibial fracture model and osteocalcin immunocytochemistry. The extraosseous tissues were isolated for study by reaming and nailing an osteotomy and excising 2 cm of periosteum on either side of the osteotomy. Specimens obtained from the healing fractures at 1 and 2 weeks after operation, respectively, were decalcified and stained for osteocalcin, a bone-specific protein, using an indirect immunoperoxidase method. The positively stained osteogenic cells appeared to be derived exclusively from the remnant of the periosteum.

Animals↗
PubMed1992

Immunity in strain 2 guinea-pigs inoculated with vaccinia virus recombinants expressing varicella-zoster virus glycoproteins I, IV, V or the protein product of the immediate early gene 62.

The immunogenicity of specific varicella-zoster virus (VZV) proteins, with emphasis upon cell-mediated immune responses, was evaluated by immunizing strain 2 guinea-pigs with vaccinia virus recombinants that express gpI (vac-gpI), gpIV (vac-gpIV) and gpV (vac-gpV) or the IE-62 protein (vac-IE-62). Vac-gpI elicited the highest initial mean T cell proliferation response [stimulation index (S.I.) 3.8 +/- 0.9 S.E.M.] whereas inoculation with vac-gpV produced the lowest primary T cell response (S.I. 2.5 +/- 1.1 S.E.M.). T cell proliferation was detected for a shorter period after immunization with vac-gpV compared to vac-gpI, vac-gpIV or vac-IE-62. A comparison of the immunogenicity of vac-gpI and vac-IE-62 with the same proteins prepared by immunoaffinity purification showed that immunization with these proteins in either form elicited virus-specific IgG antibodies and T cell recognition. The presence or absence of IgG antibodies to the IE-62 protein was used to assess protection against challenge with guinea-pig cell-adapted infectious VZV in animals that had been inoculated with vac-gpI, vac-gpIV or vac-gpV. Immunization with vac-gpI and vac-gpIV restricted VZV replication but all animals given vac-gpV developed antibodies to IE-62 after challenge with infectious VZV. Priming of the T lymphocyte response was observed in all animals immunized with VZV-vaccinia virus recombinants after subsequent exposure to infectious VZV. These experiments with VZV vac-gpI, vac-gpIV and vac-gpV in guinea-pigs suggest variability in the capacity of herpesviral glycoproteins to elicit cell-mediated immunity in vivo. Induction of virus-specific immunity using IE-62 means that this major tegument protein of VZV could be a useful component for vaccine development.

Animals↗
PubMed1992

The varicella-zoster virus immediate-early protein IE62 is a major component of virus particles.

Varicella-zoster virus (VZV) open reading frame (ORF) 62 potentially encodes a protein with considerable amino acid homology to the herpes simplex virus (HSV) immediate-early regulatory polypeptide ICP4 (or IE3). To identify and characterize its protein product(s) (IE62), we used a rabbit antiserum prepared against a synthetic peptide corresponding to the C-terminal 13 amino acids of the predicted protein. This antiserum reacted with phosphorylated polypeptides of 175 to 180 kDa that were made in VZV-infected cells and in cells infected with a vaccinia virus recombinant expressing IE62, but not in control-infected cells, confirming its specificity and reactivity to the IE62 protein. The antiserum recognized a 175-kDa polypeptide in purified virions that comigrated with a major structural protein. Comparison of this reactivity with that of an antipeptide antiserum directed against the VZV ORF 10 product (homologous to the HSV major structural protein VP16) indicates similar levels of ORF 62 and ORF 10 polypeptides in VZV virions. In contrast, antipeptide antiserum directed against the VZV ORF 29 product, the homolog of the HSV major DNA-binding protein, failed to recognize any protein in our virion preparations. Treatment of virions with detergents that disrupt the virion envelope did not dissociate IE62 from the nucleocapsid-tegument structure of the virion. Differential sensitivity of VZV virion IE62 to trypsin digestion in the presence or absence of Triton X-100 indicates that IE62 is protected from trypsin degradation by the virus envelope; since it is not a nucleocapsid protein, we conclude that it is part of the tegument. Finally, we show that the virion 175-kDa protein either can autophosphorylate or is a major substrate in vitro for virion-associated protein kinase activity.

Adenosine Triphosphate↗
PubMed1992

Hantaan virus infection of human endothelial cells.

The primary pathophysiologic finding of the viral disease known as Korean hemorrhagic fever, the etiological agent of which is Hantaan virus (HTV), is vascular instability. To investigate whether HTV was able to infect cells derived from human vascular tissue and alter their behavior, we infected in vitro primary adult human endothelial cells from saphenous veins (HSVEC). We were able to detect the presence of viral antigens in infected cells both by immunofluorescence and by Western blot (immunoblot) analysis as early as day 1 postinfection. HSVEC infected with HTV produce infectious virus during the first 3 days of infection but, at later times (days 4 to 8), show decreasing yields of virus. This contrasts with the HTV growth pattern observed for the permissive simian CV-7 cell line, which generates infectious virus up to day 12 after infection. Further investigation showed that the late decrease in viral production in HSVEC is the result of the induction of beta interferon and can be reversed by the addition of anti-beta interferon serum to the culture medium. At no time during the course of infection of HSVEC with HTV was any obvious cytopathic effect observed. When tests for changes in mRNA levels of other cytokines and endothelial cell gene products following HTV infection of HSVEC were done by reverse transcription and polymerase chain reaction methods, no significant changes were observed in the levels of interleukin 1, interleukin 6, or von Willebrand factor mRNA. We hypothesize that, while HTV can replicate in human vascular endothelial cells, the mechanism of microvascular damage seen with Korean hemorrhagic fever is not likely to be a direct effect of virus replication but may conceivably be the consequence of an immune-mediated endothelial injury triggered by viral infection.

Antigens, Viral↗
PubMed1992

The Hantaan virus M-segment glycoproteins G1 and G2 can be expressed independently.

The two glycoproteins of Hantaan virus (HTV), G1 and G2, are encoded as a continuous single open reading frame in the M segment of the virion RNA. They are believed to be synthesized contemporaneously via a polypeptide precursor which is then processed to yield two glycoproteins, both of which appear in the Golgi complex of the cell. To study the properties of G1 and G2 as separate entities, we have constructed vaccinia virus recombinants which contain the sequences for each glycoprotein individually. Both glycoproteins made from these recombinants appear normal on sodium dodecyl sulfate-polyacrylamide gels compared with HTV products made in virus-infected cells. Interestingly, in the independently expressed G2 recombinant, a stretch of hydrophobic amino acids preceding the mature G2 N terminus appears to contain the signals necessary for translocation across membranes and proper glycosylation; partial deletion of this hydrophobic sequence results in production of an nonglycosylated form of G2. Thus, both G1 and G2 appear able to be expressed in an authentic fashion quite independently of each other, using their own signal sequences. In addition, it appears that the G1 from vaccinia virus recombinants contains the motif(s) necessary for cellular targeting of the HTV glycoproteins, while G2 from vaccinia virus recombinants remains strongly associated with the endoplasmic reticulum. In contrast, cells doubly infected with G1-vaccinia virus and G2-vaccinia virus recombinants show the G2 in a predominantly perinuclear (Golgi-like) distribution, presumably targeted there through association with G1. A carboxy-terminal deletion of G1 (2-43-Vac), which lacks 82 amino acids proximal to the start of the mature G2, retains a Golgi-like distribution.

Biological Transport↗
PubMed1992

Transcription from varicella-zoster virus gene 67 (glycoprotein IV).

Three transcripts map to the varicella-zoster virus (VZV) open reading frame (ORF) 67, which encodes glycoprotein IV (gpIV). All of these transcripts are polyadenylated and are transcribed from left to right towards the genomic terminal short repeats. Previous Northern (RNA) blot analyses suggested that the most abundant of these transcripts (1.65 kb) might code for gpIV. We performed S1 nuclease protection and primer extension assays and determined that the 5' terminus of the 1.65-kb transcript maps 91 bp upstream from the gpIV initiation codon. An AT-rich region (ATAAA), -28 bp from the cap site, is a potential TATA box, and at -71 bp there is a consensus CCAAT box motif. The 3' end of the 1.65-kb transcript is 20 bp downstream of two overlapping polyadenylation signals, AATAAA and ATTAAA, and just downstream of the 3' terminus is a GU-rich sequence. These results are reminiscent of data from our analysis of the VZV gpV gene, confirming that VZV appears able to use unusual TATA box motifs. Many canonical TATA sequences are present upstream from these VZV transcriptional start sites but, apparently, are not used. We tested sequences upstream from the gpIV cap site for promoter activity in transient expression experiments by cloning a DNA fragment (+63 to -343 bp) into pCAT3M, which contains a chloramphenicol acetyltransferase reporter gene. This clone showed little constitutive promoter activity but was activated more than 200-fold by infection with VZV and 5-fold with herpes simplex virus. The two known VZV transactivating genes (those for ORF 4 and ORF 62) were tested for their abilities to activate expression from the gpIV promoter by using their cognate promoters. The ORF 4 gene was minimally active, whereas the ORF 62 gene gave twofold induction; both genes, acting together, gave fivefold induction. However, replacement of the IE62 promoter with the immediate-early cytomegalovirus promoter in the ORF 62 construct gave over 40-fold induction of chloramphenicol acetyltransferase activity under the gpIV promoter in the same assay.

Amino Acid Sequence↗
PubMed1992

Regulation of varicella-zoster virus gene expression in human T lymphocytes.

Varicella-zoster virus (VZV), a neurotropic alphaherpesvirus, is the etiologic agent of chicken pox and shingles (zoster) in humans. Using an in vitro transient expression assay, we have evaluated the ability of the putative immediate early VZV genes, ORF4, ORF61, and ORF62 (the analogs of the herpes simplex virus alpha 27, alpha 0, and alpha 4 genes, respectively), to modulate the expression of VZV genes of different putative kinetic classes in a human T lymphocyte cell line. These cells are of the type in which VZV can be readily detected in the viremic phase of human infection. We present evidence to indicate that, in this system, the gene product of ORF62 (IE62) is a major regulatory protein in VZV and is capable of activating VZV genes of all putative kinetic classes. In addition, we demonstrate that the gene product of ORF4 and, unlike the apparent situation in Vero cells, the gene product of ORF61 may play an accessory regulatory role in synergizing the activation of VZV genes induced by the gene product of ORF62 in human T lymphocytes.

Chloramphenicol O-Acetyltransferase↗
PubMed1991

Human immunodeficiency virus antibodies in sera of Australian blood donors: 1985-1990.

OBJECTIVE: To describe the results of human immunodeficiency virus type 1 (HIV-1) antibody testing of blood donations in Australia. DESIGN: Blood transfusion services tabulated the number of HIV-1 antibody tests carried out on blood donations and the number of donations found to be positive, from 1985 to 1990. SETTING: All blood transfusion services in Australia. PARTICIPANTS: All donors of blood in Australia from 1 May 1985 to 31 December 1990. OUTCOME MEASURES: The proportion of blood donations found to have HIV-1 antibody, according to State or Territory, year of donation and, when available, age, sex and donation status (repeat or first-time) of the donor. RESULTS: To the end of December 1990, 5,367,970 donations had been tested for HIV-1 antibody, and 46 were found to have the antibody, giving an overall prevalence rate of 0.86 per 100,000 donations. The highest rate was recorded in New South Wales, followed by Western Australia, and four of eight Australian States and Territories reported no donors with HIV-1 antibody. There has been no clear trend with time, but the rate is about 20% higher for 1989-1990 than for 1985-1986. Of donors found to have HIV-1 antibody, 67% were male and 33% female, and 41% reported no known or potential exposure to HIV-1 other than heterosexual contact. Among blood donors in two major Australian cities, the overall prevalence of HIV antibody was higher in those who were male, younger, and first-time donors. There has been a recent increase in the number of blood donors with HIV-1 antibody who were women reporting heterosexual contact as their only potential exposure. CONCLUSION: The rate of HIV-1 antibody in Australian blood donations remains very low and shows no clear temporal trend, but specific donor characteristics define higher rates of antibody prevalence.

Adult↗
PubMed1991

Equivalent recognition of a varicella-zoster virus immediate early protein (IE62) and glycoprotein I by cytotoxic T lymphocytes of either CD4+ or CD8+ phenotype.

Immunity to varicella-zoster virus (VZV), a member of the alpha-herpes virus family, exemplifies the host response to an ubiquitous human viral pathogen. In this investigation of the cytotoxic T lymphocyte (CTL) response to VZV, the depletion of CD4+ T lymphocytes made it possible to demonstrate CD8(+)-mediated cytotoxic function against autologous VZV-infected lymphoblastoid cells targets. CTL recognition of two major VZV proteins, the immediate early protein (IE62) and gp I, was demonstrated in limiting dilution cultures of T lymphocytes obtained from immune donors, stimulated with inactivated VZV Ag, and tested against lymphoblastoid cells infected with vaccinia recombinants expressing these VZV proteins. Among 11 VZV donors tested at least 20 y after primary infection, the mean precursor frequency for T lymphocytes that recognized the IE62 protein was 1:105,000 +/- 85,000 SD, with a range of 1:13,000 to 1:231,000. The mean frequency of CTL precursors specific for gp I in 11 subjects was equivalent, with a mean of 1:121,000 +/- 86,000 SD (range 1:15,000 to 1:228,000) (p = 0.68). Limiting dilution cultures were also prepared using purified CD4+ or CD8+ T lymphocyte populations recovered from PBMC by sterile fluorescence-activated cell sorting. CTL precursors that recognized the IE62 protein or gp I were derived from each of the major T lymphocyte populations by stimulation with inactivated VZV Ag; CD4+ and CD8+ CTL precursor frequencies for the IE62 protein and gp I were equivalent (p = 0.2). We conclude that antiviral CTL activity against targets expressing VZV proteins was mediated equally well by T lymphocytes of the CD4+ or CD8+ phenotype and that antiviral CTL function could be elicited in each subpopulation by exposure to non-infectious viral Ag.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Mechanisms of bleomycin-induced lung damage.

Bleomycins are a family of compounds produced by Streptomyces verticillis. They have potent tumour killing properties which have given them an important place in cancer chemotherapy. They cause little marrow suppression, but pulmonary toxicity is a major adverse effect. The mechanisms of cell toxicity are well described based on in vitro experiments on DNA. The bleomycin molecule has two main structural components: a bithiazole component which partially intercalates into the DNA helix, parting the strands, as well as pyrimidine and imidazole structures, which bind iron and oxygen forming an activated complex capable of releasing damaging oxidants in close proximity to the polynucleotide chains of DNA. This may lead to chain scission or structural modifications leading to release of free bases or their propenal derivatives. The mechanisms are well described based on in vitro experiments on DNA, but how they relate to intact cells in whole animals is more tenuous. Bleomycin is able to cause cell damage independent from its effect on DNA by induction lipid peroxidation. This may be particularly important in the lung and in part account for its ability to cause alveolar cell damage and subsequent pulmonary inflammation. The lung injury seen following bleomycin comprises an interstitial oedema with an influx of inflammatory and immune cells. This may lead to the development of pulmonary fibrosis, characterized by enhanced production and deposition of collagen and other matrix components. Several polypeptide mediators capable of stimulating fibroblasts replication or excessive collagen deposition have been implicated in this, but the precise role of these in bleomycin-induced fibrosis is yet to be demonstrated. Current therapy for bleomycin-induced lung damage is inadequate, with corticosteroids most often used. Given the mechanism of action described above, antioxidants and iron chelators might be beneficial. Although, studies to date are equivocal and there is insufficient evidence to promote their use clinically. Novel drugs are currently being developed and it is hoped these may be more useful.

Animals↗
PubMed1991

A detailed analysis of transcripts mapping to varicella zoster virus gene 14 (glycoprotein V).

We have characterized in detail those transcripts mapping to the varicella zoster virus (VZV) glycoprotein V (gpV) open reading frame (ORF). The analyses revealed that a major 1.95-kb and a minor 2.5-kb transcript map to these sequences for VZV strain Scott, with 1.8- and 2.3-kb transcripts in a vaccine Oka strain, consistent with intragenic repeat (R2) copy number differences. The transcripts for each strain are 5' coterminal, are polyadenylated, and do not seem to be spliced. Upstream of the cap site there are few obvious regulatory consensus sequences, but there is a potential CCAAT box at -59 bp and an unusual sequence at -25 to -33, ATTTAAATT, which may serve as the TATA box for this gene. The 3' termini map 10 to 20 bases downstream from potential polyadenylation signals: ATAAA for the 1.95-kb transcript and ACGTAAA for the 2.5-kb transcript. This transcript pattern is quite different from that observed for the gpV homologue in herpes simplex virus (HSV-1), glycoprotein C (gC). Strain Scott synthesizes about 20-fold more gpV-specific transcripts than a strain of the Oka vaccine virus, reflecting the amounts of gpV polypeptide accumulating in both strains; this implies that the defect in Oka gpV polypeptide production is at the level of transcription.

Amino Acid Sequence↗