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J Shaw

Publications and source records attributed to J Shaw.

At least 55 records · Page 3Linked to original sources

Measurement of the elastic magnetic form factor of (3)He at high momentum transfer.

New electron scattering measurements have been made that extend data on the (3)He elastic magnetic form factor up to Q(2) = 42.6 fm(-2). These new data test theoretical conjectures regarding non-nucleonic effects in the three-body system. The very small cross sections, as low as 10(-40) cm(2)/sr, required the use of a high-pressure cryogenic gas target and a detector system with excellent background rejection capability. No existing theoretical calculation satisfactorily accounts for all the available data.

Journal Article↗

Search for quadrupole strength in the electroexcitation of the delta+(1232).

High-precision 1H(e,e'p)pi(0) measurements at Q2 = 0.126 (GeV/c)2 are reported, which allow the determination of quadrupole amplitudes in the gamma*N-->Delta transition; they simultaneously test the reliability of electroproduction models. The derived quadrupole-to-dipole ( I = 3/2) amplitude ratios, R(SM) = (-6.5+/-0.2(stat+sys)+/-2.5(mod))% and R(EM) = (-2.1+/-0.2(stat+sys)+/-2.0(mod))%, are dominated by model error. Previous R(SM) and R(EM) results should be reconsidered after the model uncertainties associated with the method of their extraction are taken into account.

Journal Article↗

Validation and development of fluorescence two-dimensional differential gel electrophoresis proteomics technology.

Fluorescence two-dimensional differential gel electrophoresis (2-D DIGE*) is a new development in protein detection for two-dimensional gels. Using mouse liver homogenates (control and paracetamol (N-acetyl-p-aminophenol, APAP)-treated), we have determined the quantitative variation in the 2-D DIGE process and established statistically valid thresholds for assigning quantitative changes between samples. Thresholds were dependent on normalised spot volume, ranged from approximately 1.2 fold for large volume spots to 3.5 fold for small volume spots and were not markedly affected by the particular cyanine dye combination or by multiple operators carrying out the dye labelling reaction. To minimise the thresholds, substantial user editing was required when using ImageMaster 2D-Elite software. The difference thresholds were applied to the test system and quantitative protein differences were determined using replicate gels of pool samples and single gels from multiple individual animals (control vs treated in each gel). Throughout, the differences revealed with a particular cyanine dye combination were mirrored almost without exception when the dye combination was reversed. Both pool and individual sample analyses provided unique data to the study. The inter-animal response variability in inbred mice was approximately nine times that contributed by the 2-D DIGE process. A number of the most frequently observed protein changes resulting from APAP-treatment were identified by mass spectrometry. Several of these can be rationalised based on available data on the mechanism of APAP hepatotoxicity but others cannot, indicating that proteomics can provide further insights into the biochemical basis of APAP toxicity.

Acetaminophen↗

Cryopreservation of mouse ovarian tissue following prolonged exposure to an Ischemic environment.

In cases in which ovarian tissue is to be cryopreserved for tissue or gene banking it is important to maintain its integrity and viability. This study examined how delays between the death of an animal and the collection/cryopreservation of its ovarian tissue influenced follicle viability. Mouse ovaries were placed in PBS+antibiotic (in vitro) or left within the body (in situ) at room temperature for 0, 3, 6, 12, or 24 h following the death of the donor. These ovaries were cryopreserved at 1 degrees C/min on dry ice or in a -84 degrees C freezer using a passive cooling device or by conventional slow cooling (0.3 degrees C/min). The ovaries were grafted under the kidney capsule of ovariectomized recipient mice and collected 2 weeks later, and the size and number of follicles were determined. Cryopreserved ovarian tissue grafted immediately after the death of the donor contained numerous viable and healthy follicles independent of the cooling procedure (dry ice, 134 +/- 32; -84 degrees C, 165 +/- 54; slow, 214 +/- 55 follicles per half ovary). Tissues stored in vitro before cryopreservation retained viable follicles up to 12 h after death (dry ice, 30 +/- 15; -84 degrees C, 86 +/- 45; slow, 93 +/- 33), whereas tissue left in situ had significantly reduced follicle numbers within 3 h of death (dry ice, 36 +/- 12; -84 degrees C, 19 +/- 6; slow, 28 +/- 7). No significant difference was found between the cooling rates tested, indicating that a passive cooling container which cools at 1 degrees C/min is a suitable alternative to conventional slow cooling. We conclude that ovarian tissues for cryobanking should be cryopreserved as soon as possible after collection or death of the animal to ensure maximal follicular survival.

Animals↗

Managing severe mental illness in the community using the Mental Health Act 1983: a comparison of Supervised Discharge and Guardianship in England.

BACKGROUND: Two measures in the English Mental Health Act allow requirements to be imposed upon patients living in the community. These are Guardianship (Section 7) and Supervised Discharge (Section 25A). AIMS: The paper aims to compare patients with mental illnesses, made subject to Guardianship or Supervised Discharge. METHOD: Data on patient characteristics, impairment, needs and interventions were collected from keyworkers in a random national sample of Trusts and local authorities. Ratings were obtained on standardised measures of disability, impairment and needs. RESULTS: Patients placed on Supervised Discharge were more likely to have problems of treatment compliance and drug misuse, whilst those on Guardianship were more likely to have problems of social welfare and higher ratings of disability and impairment. Supervised Discharge has a higher proportion of African-Caribbean patients. Interventions delivered are rated as effective for both measures. CONCLUSIONS: Legal changes proposed in England include a single power for supervision in the community. This should not mean a focus on risk management to the neglect of social welfare interventions.

Adult↗

In vivo drug target discovery: identifying the best targets from the genome.

A vast number of genes of unknown function threaten to clog drug discovery pipelines. To develop therapeutic products from novel genomic targets, it will be necessary to correlate biology with gene sequence information. Industrialized mouse reverse genetics is being used to determine gene function in the context of mammalian physiology and to identify the best targets for drug development.

Animals↗

Appearance of Langerhans cells in the epidermis of Tgfb1(-/-) SCID mice: paracrine and autocrine effects of transforming growth factor-beta 1 and -beta 2(1).

A striking immunologic abnormality of normal and SCID Tgfb1(-/-) mice is the total absence of Langerhans cells in their epidermis. Here we show that transfer of Tgfb1(+/-) SCID bone marrow causes, within a few weeks, the appearance of Langerhans cells in the epidermis of gamma-irradiated and unirradiated Tgfb1(-/-) SCID recipients. In addition, local injection of 2 x 10(5) latent transforming growth factor-beta1 cDNA-transduced cloned CD4+ T lymphocytes causes the appearance of Langerhans cells in the ear epidermis of Tgfb1(-/-) SCID mice. This effect is enhanced by antigen-specific activation of these T cells. Injection of recombinant active transforming growth factor-beta 2 into the ear of Tgfb1(-/-) SCID mice also results in the migration of Langerhans cells into the epidermis locally, but no epidermal Langerhans cells are seen after systemic injections of transforming growth factor-beta 2. Our results suggest that transforming growth factor-beta can act in paracrine as well as autocrine fashion to induce the differentiation of precursors into Langerhans cells. Furthermore, these results indicate that the relative roles of different transforming growth factor-beta isoforms in vivo may be influenced by their local availability and/or the regulation of their conversion from latent into active form.

Animals↗

Analysis of the association between diabetic nephropathy and polymorphisms in the aldose reductase gene in Type 1 and Type 2 diabetes mellitus.

AIMS: To investigate the association between polymorphisms of the aldose reductase gene and diabetic nephropathy in both Type 1 and Type 2 diabetes mellitus, and to carry out a meta-analysis of published results. METHODS: We have investigated the role of two aldose reductase polymorphisms in four independent cohorts of cases and controls (two each with Type 1 and Type 2 diabetes) drawn from two ethnic populations, including 471 patients with nephropathy and 494 control diabetic patients without nephropathy. A C/T transition at position -106, and a (CA)n microsatellite marker 2.1 kb from the start site of the aldose reductase gene were genotyped in nephropathic patients and non-nephropathic controls from each cohort. RESULTS: Carriage of the -106 T allele was significantly associated with diabetic nephropathy in three of the four study groups. The Mantel-Haenszel combined odds ratio was 2.22 (95% CI 1.69, 2.94), P = 1.05 x 10(-8). We found no evidence for association of the microsatellite marker with nephropathy, despite moderate levels of disequilibrium between the two markers. Meta-analysis of published data yielded no evidence for association of the microsatellite marker with diabetic nephropathy in Type 2 diabetes, but varying degrees of association with diabetic nephropathy in Type 1 diabetes. CONCLUSIONS: Meta-analyses provide more convincing evidence of a role for the ALR2-106 marker than for the microsatellite marker in diabetic nephropathy (DN). More studies are now required to confirm these results and to establish whether the ALR2-106 polymorphism has a functional role in DN.

Adolescent↗

Comparison of the effects of in vitro and in situ storage on the viability of mouse ovarian tissue collected after death.

Ovarian tissues, collected or salvaged from endangered species at the time of gonadectomy or following their death, are being transported to genebanks for storage with the assumption that they will (subsequently) yield sufficient numbers of germ cells to help preserve the species. The present study aimed to quantify the impact of delays in collecting and/or processing ovarian tissue on the number of follicles in this tissue that remained normal after grafting. The study compared the viability of ovarian tissue stored in vitro (in phosphate-buffered saline) versus in situ (in the body) either on ice or at room temperature for 0 (non-stored fresh grafts), 3, 6, 12, 24 or 48 h. The conditions of storage had significant effects on the total number of morphologically normal follicles, with significantly more follicles in grafts developing from in vitro-stored tissue than in situ-stored tissue. Storage temperature and duration of storage, but not the storage temperature alone, influenced follicle survival. Tissue that was grafted immediately after collection (0 h) was best, but normal follicles were recovered in grafts stored in vitro (on ice or at room temperature) or in situ (on ice only) for up to 48 h before grafting. The rate of follicle loss over time was very rapid, with approximately 50% fewer follicles in grafts derived from tissue stored for only 3 h compared with non-stored fresh grafts (0 h). The results show that viable ovarian tissue can be salvaged from animals up to 48 h after death; however, in order to best protect the follicle population, the ovaries should be removed from the animal's body as soon as possible.

Animals↗

Acute liver graft failure due to emergence of lamivudine resistant hepatitis B virus: rapid resolution during treatment with adefovir.

BACKGROUND: Strategies for prevention of liver graft reinfection by hepatitis B virus (HBV) have been developed during recent years. Initially, passive immunoprophylaxis with high titre HBV immunoglobulin (HBIg), followed by lamivudine prophylaxis, and then the combination of lamivudine and HBIg have been employed. However, suboptimal use of the combination may be associated with failure of prophylaxis reflected by the emergence of HBV species with genetic changes that confer resistance to lamivudine and HBIg. Reinfection of the graft by HBV can be associated with rapid development of liver failure. CASE REPORT: A 43 year old HBV infected man received lamivudine before transplantation, and lamivudine and HBIg after transplantation. Despite prophylaxis, graft reinfection and severe hepatitis were observed. The observed serological evolution and genetic sequencing of the emergent HBV species suggested selection of lamivudine resistant and surface antigen escape mutants consecutively. Adefovir treatment began after the development of graft failure. OUTCOME: A rapid exponential decline in serum HBV titre was observed. Liver function tests normalised and signs of liver failure resolved. CONCLUSION: The use of HBIg and lamivudine permits prevention of graft reinfection by HBV for the majority of patients. Adefovir, a potent inhibitor of lamivudine resistant HBV, should be used when failure of prophylaxis is associated with graft hepatitis.

Acute Disease↗

Innexins in C. elegans.

Innexins are functionally analogous to the vertebrate connexins, and the innexin family of gap junction proteins has been identified in many invertebrates, including Drosophila and C. elegans. The genome sequencing project has identified 25 innexins in C. elegans. We are particularly interested in the roles that gap junctions may play in embryonic development and in wiring of the nervous system. To identify the particular C. elegans innexins that are involved in these processes, we are examining their expression patterns using specific antibodies and translational GFP fusions. In addition we are investigating mutant, RNAi and overexpression phenotypes for many of these genes. To date, we have generated specific antibodies to the non-conserved carboxyl termini of 5 innexins. We have constructed GFP translational fusions for 17 innexins and observed expression patterns for 13 of these genes. In total we have characterized expression patterns representing 14 innexins. Mutations have been identified in 5 of these genes, and at least 3 others have RNAi mutant phenotypes. Generalities emerging from our studies include: 1) most tissues and many individual cells express more than one innexin, 2) some innexins are expressed widely, while others are expressed in only a few cells, and 3) there is a potential for functional pairing of innexins.

Animals↗

Effects of pravastatin in 3260 patients with unstable angina: results from the LIPID study.

BACKGROUND: The LIPID study is a major trial of secondary prevention of coronary-heart-disease events that includes hospital admission with unstable angina (as well as myocardial infarction) as a qualifying event. In this substudy of LIPID, we compared subsequent cardiovascular risks and the effects of pravastatin in patients with previous unstable angina or previous myocardial infarction. METHODS: 3260 patients diagnosed with unstable angina and 5754 with acute myocardial infarction 3-36 months previously were randomly assigned 40 mg pravastatin daily or placebo over a mean of 6.0 years. The risk reduction of a range of cardiovascular events was estimated by means of the hazard ratio in Cox's proportional hazards model. FINDINGS: Among patients assigned placebo, survival in the two diagnosis groups was similar. The relative risk reduction for mortality with pravastatin was 20.6% in the myocardial infarction group and 26.3% in the unstable angina group (p=0.55). Pravastatin significantly reduced the rates of all prespecified coronary endpoints in the myocardial infarction group. In patients with previous unstable angina, coronary heart disease mortality, total mortality, myocardial infarction, a need for coronary revascularisation, the number of admissions to hospital, and the number of days in hospital were significantly lower with pravastatin. Overall, hospital admission for unstable angina was the most common endpoint (24.6% of the placebo group; 22.3% of the pravastatin group). INTERPRETATION: Patients who have survived acute myocardial infarction or unstable angina have a similar long-term prognosis, a high occurrence of subsequent unstable angina, and benefit similarly from therapy with pravastatin.

Adult↗

Quantitation of Epstein-Barr virus DNA in the blood of adult liver transplant recipients.

BACKGROUND: Posttransplant lymphoproliferation is most often observed in pediatric transplant recipients who experience primary Epstein-Barr virus (EBV) infection at the time of or after transplantation. Lymphoproliferation is believed to be caused by impaired control of EBV-infected cells, which may be of recipient or donor origin. Most studies of EBV infection and lymphoproliferation have focused on the pediatric age group. METHODS: We have undertaken a prospective study of EBV infection in adult liver transplant recipients. Sequentially collected peripheral blood lymphocytes were examined with a recently developed quantitative polymerase chain reaction assay. The assay quantitates EBV DNA genomic titre over a 5 log10 range. RESULTS: Compared with healthy EBV seropositive people not undergoing immunosuppressive therapy, blood EBV DNA titre is elevated in patients with liver disease before transplantation. Overall, highest titres were observed during the first posttransplant month, and in the context of antilymphocyte therapy. In one patient, lymphoproliferation was associated with high titres which fell during reduction of immunosuppressive therapy. In another patient with lymphoproliferation of donor lymphocyte origin, blood EBV DNA titre was not as high. CONCLUSIONS: EBV proliferation is seen in the context of advanced liver disease and after liver transplantation. EBV DNA quantitation is a useful tool to examine the effects of immunosuppression on EBV-associated lymphoproliferation, and may be an essential technique for programs exploring the merits of EBV adoptive immunotherapy.

Adult↗

Follicular development in transplanted fetal and neonatal mouse ovaries is influenced by the gonadal status of the adult recipient.

OBJECTIVE(S): To investigate the pattern of follicular development in transplanted fetal and neonatal mouse ovaries in the presence or absence of the recipient's own ovaries. DESIGN: Controlled experiment. SETTING: Academic research laboratory, Department of Physiology, Monash University, Clayton, Australia. INTERVENTION(S): Mouse ovaries from 16-day-old fetuses, 3-day-old neonates, and 10-day-old neonates were transplanted under the kidney capsule of adult female mice, which either retained their own ovaries in situ or were bilaterally ovariectomized. MAIN OUTCOME MEASURE(S): Histologic analysis. RESULT(S): By 4 weeks after transplantation, fetal and neonatal ovaries transplanted to ovariectomized recipients displayed a pattern of follicular development similar to that observed in in situ adult mouse ovaries. In contrast, follicular development did not progress beyond the early antral stage in fetal and 3-day-old ovaries transplanted to recipients that retained their in situ ovaries. However, 10-day-old ovaries transplanted to recipients that retained their in situ ovaries displayed full follicular development and corpora lutea formation by 8 weeks after transplantation. CONCLUSION(S): Follicular development in transplanted immature ovarian tissue is influenced by the age of the donor ovary and gonadal status of the recipient. (Fertil Steril(R) 2000;74:000-00. Copyright2000 by American Society for Reproductive Medicine.)

Age Factors↗

Release of TNFalpha in response to SiC fibres: differential effects in rodent and human primary macrophages, and in macrophage-like cell lines.

Asbestos has been implicated in the pathogenesis of several lung diseases, but its mechanism of action is not fully understood. However, asbestos-induced oxidative stress and production of inflammatory cytokines may play a significant role. TNFalpha is an inflammatory cytokine which has a central role in inflammation and fibrosis due to its ability to stimulate fibroblasts and collagen deposition. In this study, a panel of fibres designated either pathogenic or non-pathogenic in recent animal studies, were utilized. The amount of TNFalpha released after a 16-hour exposure to the panel of fibres was compared in four different cell types; two primary macrophage cell types and two cell lines. TNFalpha release by cells exposed to the panel did not equate to pathogenicity, although the most pathogenic fibre caused three out of the four cell types tested, to produce the greatest amount of TNFalpha. Primary rat cells and primary human cells behaved in a similar manner as regards to TNFalpha production; the cell lines behaved quite differently to their primary counterparts with regards to TNFalpha production in this study.

Animals↗