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Biomedical subjects

R A Kay

Publications and source records attributed to R A Kay.

At least 19 recordsLinked to original sources
PubMed2001

Overexpression and poly-ubiquitylation of the DEAD-box RNA helicase p68 in colorectal tumours.

The DEAD box RNA helicase, p68, is upregulated in exponentially growing cells and shows cell cycle-dependent changes in nuclear localization. Although some other DEAD box proteins have been implicated in cancer, there have been no reports of any link between p68 status and carcinogenesis. In the present study we have analysed specimens from 50 patients with colorectal adenocarcinomas, including cases in which an adenomatous polyp was also present, by immunohistochemistry and Western blotting. Our data indicate that p68 protein is consistently overexpressed in tumours as compared with matched normal tissue. Examination of the levels of p68 mRNA from both normal and tumour tissue showed no obvious specific increase in p68 mRNA levels in tumours nor any evidence of underlying mutations in the p68 coding region. Interestingly, however, the accumulated p68 appears to be poly-ubiquitylated, suggesting a possible defect in proteasome-mediated degradation in these tumours. This overexpression/ubiquitylation is observed in both pre-invasive and invasive lesions suggesting that the dysregulation of p68 expression occurs early during tumour development. Finally, we demonstrate that ubiquitylation of p68 occurs in cultured cells, thereby providing a model for the molecular analysis of this process and its potential role in tumorigenesis.

Animals↗
PubMed2000

Antigen triggering selectively increases TCRBV gene transcription.

When the TCR binds Ag it is phosphorylated, internalized, and degraded. We wished to examine whether this process was accompanied by a specific concomitant increase in TCR mRNA levels. To do this, PBMC and a T cell clone were cultured with a series of superantigens and an alloantigen. Only T cells specifically responding to an antigenic stimulus had increased levels of TCR beta-chain variable (TCRBV)-specific mRNA. This response was apparent after 48 h, peaked around 72 h, and was still elevated after 7 days. Increased gene transcription appeared to be driven solely by Ag as specific Ag depletion prevented culture supernatants transferring this effect. The level of TCRBV mRNA elevation was not influenced by the stimulating Ag, but appeared dependent on the gene encoding the stimulated TCR. Reporter gene assays, using cloned TCRBV gene promoters, confirmed both that TCR gene transcription rises after stimulation and that basal and stimulated levels of TCR transcription vary between different TCRBV genes. These data conclusively demonstrate that there is no direct relationship between TCRBV mRNA and T cell number, and that future repertoire studies must take both factors into account.

Adult↗
PubMed1997

Long-term alloreactive T cell lines and clones express a limited T cell receptor repertoire.

Alloreactive T cells recognize either determinants of the intact donor MHC molecules displayed on the surface of transplanted-cells or peptide fragments of donor antigens associated with self-MHC molecules by means of their T cell receptors (TCR). To investigate the relationship between the TCR beta chain structure and allorecognition, we established and characterized four long-term T cell lines and seven T cell clones derived following a mixed lymphocyte reaction (MLR) between fully histoincompatible DA (RT1a) and LEW (RT1(1)) rat lymph node cells. These DA anti-LEW T cells were phenotypically CD4+, CD8-, alpha beta TCR+ and produced interferon-gamma but not IL-4, consistent with being Th1 CD4+ T cells. As might be expected, these cells were not significantly cytotoxic and did not display suppressor activity. Analysis of the TCR beta chain gene structure revealed a very restricted repertoire in both long-term lines and clones. The TCRBV6S1 gene was present in 15/21 of the alloreactive T cell mRNA transcripts but only 1/12 of unstimulated DA splenic TCR mRNA transcripts (p = 0.0018). Similarly, the TCRBJ2S1 gene was also used frequently in the alloreactive transcripts (17/21) but in only 2/12 unstimulated splenic transcripts (p = 0.0013). Furthermore, all 15 of the alloreactive TCRBV6S1 transcripts had a distinctive four amino acid N region motif not present in any of the unstimulated TCR transcripts (p = 0.0003). These experiments reveal a distinct homogeneity amongst stable allogeneic T cells in culture. If these results reflect the situation in vivo, the possibility exists that specific immunotherapy may be successful in preventing allograft rejection.

Amino Acid Sequence↗
PubMed1996

Maintaining quality of care and patient satisfaction with radical prostatectomy in the era of cost containment.

OBJECTIVES: To determine the effect of shortened hospital stay after radical retropubic prostatectomy on costs, adverse surgical outcomes, and patient satisfaction. METHODS: The effect of changes in preoperative counseling, perioperative care, and analgesic management on hospital length of stay; mean cost per case and cost per hospital day; and 30-day complication, hospital readmission, and mortality rates were analyzed for a consecutive sample of 374 patients undergoing radical prostatectomy between July 1989 and November 1995. Satisfaction with length of stay, analgesic regimen, and surgical outcome was assessed in a random subset of 150 patients by anonymous questionnaire. RESULTS: Length of stay (LOS) was shortened from a median 7 to 2 nights after surgery during the study (P < 0.0001), whereas the acute complication, 30-day readmission, and 30-day mortality rates remained constant. Reducing LOS resulted in a 43% decrease in mean cost per case while mean cost per day increased by 22% to 35%. Overall patient satisfaction was high, with 83.5% of patients rating LOS as "just right" and 89.2% reporting they were "satisfied" or "very satisfied" with their pain control after surgery. CONCLUSIONS: Shortened LOS after radical retropubic prostatectomy can be accomplished safely and can meet with high levels of patient satisfaction while significantly reducing hospital-related costs. The potential for further incremental reductions in cost with reductions in LOS to less than 2 nights appears to be small, and future efforts at cost reduction for this procedure should center on decreasing the intensity of care during hospitalization.

Cost Control↗
PubMed1996

TCR gene polymorphisms and autoimmune disease.

Autoimmunity may result from abnormal regulation within the immune system. As the T cell is the principal regulator of the immune system and its normal function depends on immune recognition or self/non-self discrimination, abnormalities of the idiotypic T-cell receptor (TCR) may be one cause of autoimmune disease. The TCR is a clonally distributed, cell-surface heterodimer which binds peptide antigen when complexed with HLA molecules. In order to recognize the variety of antigens it may possibly encounter, the TCR, by necessity, is a diverse structure. As with immunoglobulin, it is the variable domain of the TCR which interacts with antigen and exhibits the greatest amount of amino acid variability. The underlying genetic basis for this structural diversity is similar to that described for immunoglobulin, with TCR diversity relying on the somatic recombination, in a randomly imprecise manner, of smaller gene segments to form a functional gene. There are a large number of gene segments to choose from (particularly the TCRAV, TCRAJ and TCRBV gene segments) and some of these also exhibit allelic variation. Finally, polymorphisms in non-coding regions of TCR genes, leading to biased recombination or expression, are also beginning to be recognized. All these factors contribute to the polymorphic nature of the TCR, in terms of both structure and repertoire formation. It follows that inherited abnormalities in either coding or regulatory regions of TCR genes may predispose to aberrant T-cell function and autoimmune disease. This review will outline the genomic organization of the TCR genes, the genetic mechanisms responsible for the generation of diversity, and the results of investigations into the association between germline polymorphisms and autoimmune disease.

Alleles↗
PubMed1995

A subset of Sjögren's syndrome associates with the TCRBV13S2 locus but not the TCRBV2S1 locus.

HGPSS associates with the TCRBV6S7 locus within the TCR beta-chain gene complex. However, V beta 6.7 T cells, encoded by this locus, have never been implicated in the salivary gland destruction that characterizes primary Sjögren's syndrome. Both V beta 13 and V beta 2 T cells have been implicated in glandular destruction. We therefore analyzed the association of HGPSS with both TCRBV2S1, the only TCRBV2 locus, and the TCRBV13S2 locus (the TCRBV13 family member which lies closest to TCRBV6S7). Our results show that the prevalence of TCRBV13S2*2 homozygotes is significantly increased in HGPSS and that there is a high degree of linkage disequilibrium between this locus and TCRBV6S7 not previously described across the TCR beta-chain gene complex. However, HGPSS does not associate with the TCRBV2S1 locus. These results suggest that it is the V beta 13.2 T cell which may be responsible for the autoimmune destruction that characterizes HGPSS and that the previous association of this condition with the TCRBV6S7 locus is primary due to the linkage disequilibrium that exists between it and TCRBV13S2.

Base Sequence↗
PubMed1995

Immunology of systemic rheumatoid disease.

Extra-articular or systemic features occur commonly in seropositive erosive rheumatoid arthritis (RA). Clinical, pathological and immunogenetic evidence suggests that nodule formation, vasculitis and Felty's syndrome can be considered as manifestations of the same fundamental disease process as rheumatoid synovitis. However, while synovitis seems likely to be driven by macrophage activation induced by Th1 cells, systemic involvement in RA is characterised by B cell overactivity, immune complex formation and complement consumption, suggesting that Th2 cells are involved in the pathogenesis of extra-articular rheumatoid disease.

Arthritis, Rheumatoid↗
PubMed1994

Genetic control of the human V beta 13.2 T cell repertoire: importance of allelic variation outside the coding regions of the TCRBV13S2 gene.

In humans, the T cell repertoire is influenced by HLA, T cell receptor null alleles and antigen. Here, we describe a novel mechanism, independent of superantigen or T cell receptor structure which influences the T cell repertoire in a V beta-dependent manner. We have identified a biallelic locus, the TCRBV13S2 T cell receptor gene, where allelic differences predominate in the non-coding regions including transitions, transversions and frameshift deletions. The expressed protein is non-polymorphic at this locus. The TCRBV13S2 genotype profoundly influences the circulating levels of V beta 13.2 CD4 T cells but does not affect T cell receptor expression or function.

Alleles↗
PubMed1994

[T-lymphocyte receptor genes: genome organization and genetic mechanisms of repertoire diversity].

The T-cell receptor (TCR) is fundamental to the immune process in both health and disease. Reviewed here is the genetic organisation of the gene complexes which encode the TCR polypeptide chains alpha, beta, gamma, and delta. The TCR is by necessity a diverse structure and we consider the genetic mechanisms responsible for this. These include multiple variable gene segment isotypes, somatic recombination of gene segments, imprecisions in the recombination process and allelic variations in gene segments structure and regulation.

Analysis of Variance↗
PubMed1994

[Idiotypic T-lymphocyte receptor in animal and human autoimmune diseases].

Animal models have demonstrated that the T-cell repertoire is restricted when the response to defined autoantigens is studied. Anti-V beta specific monoclonal antibodies or specific V beta-derived peptides can be used to manipulate autoreactive T-cells to either prevent or treat established experimental disease in animals. In some animal models of arthritis, inherited differences in the TCR repertoire can protect against the development of experimental autoimmune disease. Human studies have generally given conflicting results with regard to the role of the TCR complexes as susceptibility loci for disease. This may be due to the heterogeneity present in the human population and/or in the diseases studied. In some diseases, where there is convincing evidence for putative autoantigens (multiple sclerosis) or distinct immunodysfunctional pathology (hypergammaglobulinaemic primary Sjögren's syndrome), restricted TCR repertoires and germline TCR susceptibility loci can be discerned. Recent evidence suggests that autoimmune disease may eventually be mapped to regulatory regions of the TCR V genes rather than the allelic differences in coding region structure. This may have implications for the future therapy of autoimmune rheumatic disease.

Animals↗
PubMed1991

Microalgae as food and supplement.

The microalgae Chlorella spp., Dunaliella spp., and Scenedesmus spp., and the cyanobacteria Spirulina spp., and Aphanizomenon flos-aquae, are being used as nutrient-dense foods and sources of fine chemicals. They have significant amounts of lipid, protein, chlorophyll, carotenoids, vitamins, minerals, and unique pigments. They may also have potent probiotic compounds that enhance health. Their historical and current use are reviewed in this article.

Animals↗
PubMed1991

An abnormal T cell repertoire in hypergammaglobulinaemic primary Sjögren's syndrome.

T cell antigen specificity is determined by the products of the genes which encode the variable regions of their receptors. Of the T cell receptor (TCR) variable region gene products examined, only V beta 6.7a TCR-positive lymphocytes were reduced in primary Sjögren's syndrome patients with IgG1 hypergammaglobulinaemia compared with an age-, sex- and HLA-matched control population. The levels of V beta 6.7a T cells were also significantly reduced when these patients were compared with an age- and sex-matched but HLA-unmatched control group and non-tissue typed normal people of both sexes. Since published studies show no such abnormality in rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases, this abnormality may reflect a pathogenic process specific to primary Sjögren's syndrome.

Adult↗
PubMed1990

Selective polyclonal increase of immunoglobulin G1 subclass: a link with Sjögren's syndrome.

A selective polyclonal increase in IgG1 has been described previously in a group of patients with connective tissue disease; nine of the 16 patients had a prior diagnosis of systemic lupus erythematosus (SLE). A detailed clinical and serological study of 32 patients with this immunoglobulin abnormality has now been made. Most cases showed a characteristic autoantibody profile of antinuclear antibody, rheumatoid factor, and antibodies to Ro and La. Sjögren's syndrome was diagnosed as 'definite' in 16 cases and 'possible' in seven cases by Fox's criteria. The remainder had unclassified connective tissue disease (three), rheumatoid arthritis with dry eyes (two), SLE (one), scleroderma (two), and Raynaud's disease (one). Extraglandular features were invariably present in patients with primary Sjögren's syndrome. The highest concentrations of IgG1 were found in patients with the shortest disease duration. Selective polyclonal increase of IgG1 should alert the doctor to the development of Sjögren's syndrome, usually with extraglandular disease and antibodies to Ro and La.

Acute-Phase Reaction↗
PubMed1989

The immunological consequences of feeding cholera toxin. II. Mechanisms responsible for the induction of oral tolerance for DTH.

The mechanisms behind the induction of oral tolerance after feeding cholera toxin (CT) were examined using cell and serum transfer protocols. The feeding of CT or cholera toxoid (TD) induced a splenic cell capable of inhibiting the induction of systemic delayed-type hypersensitivity (DTH) but not humoral immunity. Depletion studies showed that this cell was Thy-1.2 positive. Transfer experiments suggested that suppressor cell activity was present in the mesenteric lymph nodes (MLN) and spleens of donor mice 1 week but not 3 days after feeding CT. When spleen cells were transferred to syngeneic recipients at various times after immunization, they were more effective at inhibiting systemic DTH when transferred within a short time of immunization. If the cells were transferred 6 days after immunization they no longer suppressed the development of DTH, which suggested that they inhibit the afferent limb of this immune response. This has been confirmed by the failure of a tolerogenic dose of CT, administered by gavage, to suppress the activity of mature effector TDTH cells. Serum collected 1 hr after feeding CT also suppressed the induction of systemic DTH. However, the tolerogenic activity of CT-fed serum was abrogated by the pretreatment of recipients with cyclophosphamide (Cy) (100 mg/kg), suggesting that this activity is mediated through the induction of suppressor cells. Transfer of fed serum, however, did not induce the splenic suppressor cell described above and we would suggest that several mechanisms may operate in the mucosal regulation of systemic DTH.

Administration, Oral↗
PubMed1989

The immunological consequences of feeding cholera toxin. I. Feeding cholera toxin suppresses the induction of systemic delayed-type hypersensitivity but not humoral immunity.

Immunization of adult BALB/c mice with 1 microgram cholera toxin (CT) in complete Freund's adjuvant (CFA) induced both humoral (IgG and IgA) and cell-mediated (DTH) immunity. Although an immunopurified, formalinized, cholera toxoid (TD) in CFA was inferior to the native holotoxin at inducing antitoxin antibodies, both cholera-derived antigens were equally immunogenic for specific DTH. When mice were fed either 1 microgram CT or 5 microgram TD 1 week before immunization, the induction of DTH was inhibited but the development of specific antibody was the same as in sham-fed controls. A feed of 10 micrograms CT not only suppressed the induction of DTH but also enhanced the IgG antitoxin responses measured 1 week after immunization. A dose of TD (50 micrograms), with a similar cholera toxin B subunit content, also induced oral tolerance for DTH but had no effect on the subsequent development of humoral immunity. The smallest doses of CT or TD fed (0.1 microgram and 0.5 microgram, respectively) failed to affect the development of either limb of the systemic immune response. These results suggest that oral tolerance for DTH is not consequent upon the metabolic actions of CT but that stimulation of systemic antibodies after enteric administration may be. Pretreating mice with cyclophosphamide (Cy) (100 mg/kg) before feeding CT abrogated the induction of oral tolerance for DTH but had no effect on humoral immunity, suggesting that suppressor T cells may be responsible for the induction of oral tolerance in these animals.

Administration, Oral↗