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J M White

Publications and source records attributed to J M White.

At least 37 records · Page 2Linked to original sources
PubMed2003

Direct spectroscopic evidence of the cross-coupling reaction between CH(2)(a) and CF(3)(a) on Ag(111).

The cross-coupling reaction between CH2 and CF3 on Ag(111) was studied with reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed reaction spectroscopy (TPRS). Adsorbed CF3CH2(a) was, for the first time, spectroscopically identified as an intermediate in the reaction to form CF2CH2. It is formed by migratory methylene insertion into Ag-CF3. CF3CH2(a) undergoes beta-fluoride elimination to form CF2CH2. Our results provide direct new fundamental insight into Fischer-Tropsch synthesis.

Journal Article↗
PubMed2003

Self-assembly of fluid-filled KHCO(3) microfibers.

Self-assembly of KHCO(3) fibers is observed when glassy oligomerized films of poly[(aminopropyl)siloxane] containing K(+) ions, denoted K(+)/poly-APS, are exposed to CO(2) and H(2)O. The fibers are crystalline, narrow (0.4-3 microm diam), high aspect ratio (up to at least 300), and, on the basis of Raman spectroscopy, dominated by KHCO(3). The fibers contain fluid that is dominated by aqueous potassium formate (KOOCH). A multistep phenomenological model is proposed to account for the self-assembly.

Bicarbonates↗
PubMed2003

Tetanus in England and Wales, 1984-2000.

A review of national tetanus surveillance in England and Wales during 1984-2000 was undertaken to evaluate the surveillance system and national vaccination policy. Hospital Episode Statistics for tetanus in England for fiscal years 1989/90-1995/6 were also examined to estimate under-reporting. A total of 175 cases of tetanus were reported, giving an annual incidence of 0.20 per million, the lowest levels ever recorded. The highest incidence was in those aged over 64 years (0.66 per million) with no significant sex difference. Twenty (11%) cases were reported in people who were eligible for routine childhood vaccination. Outdoor injuries were the commonest reported exposure risk. Tetanus case under-reporting was estimated as 54-64%. We conclude that GPs should ensure that all their patients are fully vaccinated, targeting those born before 1961. High childhood tetanus vaccination coverage remains a priority. As the disease becomes rarer, enhanced tetanus case surveillance is essential for tetanus immunization policy evaluation.

Adolescent↗
PubMed2003

Total registration of non-Hodgkin's lymphoma and Hodgkin's disease in Scotland: effect of deprivation and caseload on outcome.

All cases S16 years of age with a histological diagnosis of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD) presented in Scotland between 1 January 1994 and 31 December 1996 were registered prospectively in the Scotland and Newcastle Lymphoma Group database by a process of total registration. The census population of Scotland in 1996-1997 was 5.1 million. One thousand seven hundred and sixty three patients were registered with NHL and 350 patients with HD. These patients have been followed up for a median of 47 months in the case of NHL and 51 months for HD cases. Actuarial 5-year survival for adult NHL was 35% and for HD, 75%. Outcome for both NHL and HD was particularly poor in the population over 60 years with median survival of 18 months for NHL and 27 months for HD. When analysis of survival was related to degree of material deprivation using the Carstairs score a significantly poorer survival was seen for NHL with increasing deprivation that could not be explained by a different pattern of age or stage at presentation. Deprivation had no impact on incidence or survival in HD. Analysis of impact of caseload of the physician initiating therapy showed no significant difference in 5-year survival.

Adolescent↗
PubMed2002

Enhanced surveillance scheme for suspected meningococcal disease in five regional health authorities in England: 1998.

Enhanced surveillance of meningococcal disease (ESMD) began in five English regions on 1st January 1998. The aims of the scheme were to obtain accurate incidence data and develop a robust surveillance system with which to monitor the impact of a new meningococcal serogroup C conjugate vaccine. During 1998, 2,314 suspected cases of meningococcal disease were identified. The majority (84%) was classified as invasive meningococcal disease, with infection of N. meningitidis confirmed in 66%. Sixteen per cent of suspected cases were subsequently given an alternative diagnosis. Age differences between those classified as meningococcal disease and those not, implied a higher index of suspicion of meningococcal disease in younger children. Regions with high rates of meningococcal disease were due to a higher rate of serogroup C. ESMD increased ascertainment of meningococcal disease and deaths. Cases were 34% greater than identified through statutory notifications, an additional 6.8% confirmed infections were identified than were reported to the PHLS Meningococcal Reference Unit (MRU) and deaths were 24% greater than death registrations. These data were used to inform the national meningococcal serogroup C conjugate vaccination programme in England and Wales. In 1999 ESMD was extended to all regions of England, Wales and Northern Ireland.

Adolescent↗
PubMed2002

Parental confidence in measles, mumps and rubella vaccine: evidence from vaccine coverage and attitudinal surveys.

BACKGROUND: The measles, mumps and rubella (MMR) vaccine has been the focus of considerable adverse publicity in recent years. AIM: To describe recent trends in parental attitudes to, and coverage of, MMR vaccine. DESIGN OF STUDY: Routine surveillance of vaccine coverage and cross-sectional surveys of parental attitudes. SETTING: All health authorities in England (vaccine coverage) and 132 enumeration districts in England (attitude survey). METHOD: Quarterly MMR vaccine coverage for all resident children in England at two years of age was requested from computerised child health information systems. Data was also obtained from 26 English health authorities/trusts on MMR coverage at 16 months of age. The proportion of mothers who believed that MMR vaccine was safe or carried only a slight risk, and the proportion who intended to fully vaccinate any future children, was obtained from biannual interviews with a national representative sample of over 1000 mothers of children under three years of age. RESULTS: Vaccine coverage at two years of age fell 8.6% (95% confidence interval [CI] = 8.4 to 8.8) between April and June 1995 and between April and June 2001. In September 2001, 67% of mothers reported that the MMR vaccine was safe or carried only a slight risk and 92% of mothers agreed with the statement: 'If I had another child in the future I would have them fully immunised against all childhood diseases'. CONCLUSIONS: Despite considerable adverse publicity, the fall in MMR coverage has been relatively small, mothers' attitudes to MMR remain positive, and most continue to seek advice on immunisation from health professionals. As the vast majority of mothers are willing to have future children fully immunised, we believe that health professionals should be able to use the available scientific evidence to help to maintain MMR coverage.

Attitude to Health↗
PubMed2002

Susceptibility of young offenders to measles and rubella: an antibody prevalence study using oral fluid samples.

Three hundred and two oral fluid samples collected in January 2001 from male young offenders aged 18 to 21 years at HMP Hindley were screened for measles and rubella specific IgG, using 'in-house' amplified ELISA assays. MMR (measles/mumps/rubella) vaccine, offered at the same time, was accepted by 68.1% of the prisoners (92.7% of those agreeing to oral fluid antibody testing). Antibody prevalences were 92.1% for rubella and 80.8% for measles. This may, however, underestimate true prevalence as the sensitivity of the oral fluid assays used may be relatively poor in adults. Susceptibility levels are theoretically high enough to result in outbreaks should either infection enter this closed institutional environment. Since a measles outbreak would carry significant morbidity and rubella would represent a risk to associated non-immune women of childbearing age, it is suggested that prison health services should offer MMR to young offenders on entry.

Adolescent↗
PubMed2001

Quantitative determination of the metastability of flat Ag overlayers on GaAs(110).

Atomically flat ultrathin Ag films on GaAs(110) can be formed through a kinetic pathway. However, such films are metastable and will transform to 3D islands upon high temperature annealing. Using scanning tunneling microscopy, we have measured quantitatively the layer-resolved metastability of flat Ag overlayers as they evolve toward their stable state, and deduced the corresponding kinetic barrier the system has to overcome in reaching the stable state. These results indicate that the metastability of the Ag overlayer is defined by the quantum nature of the conduction electrons confined within the overlayer.

Journal Article↗
PubMed2001

Friend of GATA-1 represses GATA-3-dependent activity in CD4+ T cells.

The development of naive CD4+ T cells into a T helper (Th) 2 subset capable of producing interleukin (IL)-4, IL-5, and IL-13 involves a signal transducer and activator of transcription (Stat)6-dependent induction of GATA-3 expression, followed by Stat6-independent GATA-3 autoactivation. The friend of GATA (FOG)-1 protein regulates GATA transcription factor activity in several stages of hematopoietic development including erythrocyte and megakaryocyte differentiation, but whether FOG-1 regulates GATA-3 in T cells is uncertain. We show that FOG-1 can repress GATA-3-dependent activation of the IL-5 promoter in T cells. Also, FOG-1 overexpression during primary activation of naive T cells inhibited Th2 development in CD4+ T cells. FOG-1 fully repressed GATA-3-dependent Th2 development and GATA-3 autoactivation, but not Stat6-dependent induction of GATA-3. FOG-1 overexpression repressed development of Th2 cells from naive T cells, but did not reverse the phenotype of fully committed Th2 cells. Thus, FOG-1 may be one factor capable of regulating the Th2 development.

Animals↗
PubMed2001

Treatment of steroid-refractory acute graft-versus-host disease with anti-CD147 monoclonal antibody ABX-CBL.

ABX-CBL, an immunoglobulin M murine monoclonal antibody, recognizes CD147 and initiates cell killing through complement-mediated lysis. In a dose-finding trial, 27 patients with steroid-refractory acute graft-versus-host disease (GVHD) received ABX-CBL at 0.01 (presumed no effect dose), 0.1, 0.2, or 0.3 mg/kg per day, and an additional 32 patients were given ABX-CBL at 0.2 or 0.15 mg/kg per day. All patients had undergone allogeneic transplantation for malignant or nonmalignant disorders and received GVHD prophylaxis, generally with methotrexate- and cyclosporine-containing regimens. None responded to methylprednisolone, given for a minimum of 3 days. ABX-CBL was started 20 to 236 (median, 47) days after transplantation; it was given for 7 consecutive days and was followed by 2 infusions per week for 2 more weeks. Among 51 patients evaluable for efficacy, 26 (51%) responded, including 13 with complete responses (CR) and 13 with partial responses (PR). CR lasting 14 days or longer or PR lasting 7 days or longer occurred in 21 (41%; 8 CR, 13 PR) patients, including 19 of 43 (44%) patients who received 0.1 to 0.3 mg/kg ABX-CBL and 2 of 8 (25%) patients given 0.01 mg/kg per day. Myalgias at doses 0.2 mg/kg or greater were dose limiting and resolved without sequelae. Causes of death included organ failure, progressive GVHD, and infection. No death was attributed to ABX-CBL. At 6 months after the initiation of ABX-CBL therapy, 26 (44%) patients were surviving. These results are encouraging. Further studies on the use of ABX-CBL in the management of GVHD are warranted.

Acute Disease↗
PubMed2001

Precipitated withdrawal following codeine administration is dependent on CYP genotype.

The role of metabolic polymorphism in the development of physical dependence to codeine was assessed in cytochrome P450 2D2 (CYP2D2) deficient Dark Agouti and CYP2D2 intact Sprague-Dawley rats by assessment of the severity of naloxone precipitated withdrawal after codeine and morphine administration. Plasma morphine concentrations after codeine were significantly higher (P<0.01) in Sprague-Dawley than in Dark Agouti rats with metabolic ratios of 0.71 +/- 0.27 and 0.07 +/- 0.04, respectively. Withdrawal after codeine resulted in significantly greater hypothermia (3.5-4 degrees C, P<0.0001) in Sprague-Dawley animals compared to the other groups. Body weight loss was similar for all groups ranging from 6.2 +/- 0.4 to 8.2 +/- 0.6 g. When strain and treatment data were combined, a relationship between body temperature and plasma morphine concentration could be described by the inverse Hill equation (r(2)=0.76, EC(50)=556 +/- 121 ng/ml, n=2.9 +/- 1.5). These data indicate that dependence and withdrawal after codeine administration are dependent on its bioconversion to morphine.

Analgesics, Opioid↗
PubMed2001

Xenopus ADAM 13 is a metalloprotease required for cranial neural crest-cell migration.

BACKGROUND: Cranial neural-crest (CNC) cells originate from the lateral edge of the anterior neuroepithelium and migrate to form parts of the peripheral nervous system, muscles, cartilage, and bones of the face. Neural crest-cell migration involves the loss of adhesion from the surrounding neuroepithelium and a corresponding increase in cell adhesion to the extracellular matrix (ECM) present in migratory pathways. While proteolytic activity is likely to contribute to the regulation of neural crest-cell adhesion and migration, the role of a neural crest-specific protease in these processes has yet to be demonstrated. We previously showed that CNC cells express ADAM 13, a cell surface metalloprotease/disintegrin. Proteins of this family are known to act in cell-cell adhesion and as sheddases. ADAMs have also been proposed to degrade the ECM, but this has not yet been shown in a physiological context. RESULTS: Using a tissue transplantation technique, we show that Xenopus CNC cells overexpressing wild-type ADAM 13 migrate along the same hyoid, branchial, and mandibular pathways used by normal CNC cells. In contrast, CNC cell grafts that express protease-defective ADAM 13 fail to migrate along the hyoid and branchial pathways. In addition, ectopic expression of wild-type ADAM 13 results in a gain-of-function phenotype in embryos, namely the abnormal positioning of trunk neural-crest cells. We further show that explanted embryonic tissues expressing wild-type, but not protease-defective, ADAM 13 display decreased cell-matrix adhesion. Purified ADAM 13 can cleave fibronectin, and tissue culture cells that express wild-type, but not protease-defective, ADAM 13 can remodel a fibronectin substrate. CONCLUSIONS: Our findings support the hypothesis that the protease activity of ADAM 13 plays a critical role in neural crest-cell migration along defined pathways. We propose that the ADAM 13-dependent modification of ECM and/or other guidance molecules is a key step in the directed migration of the CNC.

ADAM Proteins↗
PubMed2001

IFNgamma and lymphocytes prevent primary tumour development and shape tumour immunogenicity.

Lymphocytes were originally thought to form the basis of a 'cancer immunosurveillance' process that protects immunocompetent hosts against primary tumour development, but this idea was largely abandoned when no differences in primary tumour development were found between athymic nude mice and syngeneic wild-type mice. However, subsequent observations that nude mice do not completely lack functional T cells and that two components of the immune system-IFNgamma and perforin-help to prevent tumour formation in mice have led to renewed interest in a tumour-suppressor role for the immune response. Here we show that lymphocytes and IFNgamma collaborate to protect against development of carcinogen-induced sarcomas and spontaneous epithelial carcinomas and also to select for tumour cells with reduced immunogenicity. The immune response thus functions as an effective extrinsic tumour-suppressor system. However, this process also leads to the immunoselection of tumour cells that are more capable of surviving in an immunocompetent host, which explains the apparent paradox of tumour formation in immunologically intact individuals.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Defective lymphotoxin-beta receptor-induced NF-kappaB transcriptional activity in NIK-deficient mice.

The role of NF-kappaB-inducing kinase (NIK) in cytokine signaling remains controversial. To identify the physiologic functions of NIK, we disrupted the NIK locus by gene targeting. Although NIK-/- mice displayed abnormalities in both lymphoid tissue development and antibody responses, NIK-/- cells manifested normal NF-kappaB DNA binding activity when treated with a variety of cytokines, including tumor necrosis factor (TNF), interleukin-1 (IL-1), and lymphotoxin-beta (LTbeta). However, NIK was selectively required for gene transcription induced through ligation of LTbeta receptor but not TNF receptors. These results reveal that NIK regulates the transcriptional activity of NF-kappaB in a receptor-restricted manner.

Animals↗
PubMed2001

Hyperalgesic responses in methadone maintenance patients.

Opioid substitution treatment for dependence may alter sensitivity to pain. Previous studies on pain sensitivity in methadone maintenance patients have yielded contradictory results. This study compared nociceptive responses between 16 patients on stable, once daily, doses of methadone and 16 matched control subjects. Two types of nociceptive stimuli were used: (1) electrical stimulation; and (2) a cold pressor test. Two parameters were measured: detection for onset of pain, and pain tolerance. Methadone patients were tested over an inter-dosing period: at the time of trough plasma methadone concentration (0 h), and 3 h after their daily dose. Control subjects were tested twice 3 h apart. Blood samples were collected to determine plasma methadone concentration. In methadone patients, trough to peak increases in mean R-(-)- and S-(+)-methadone concentrations (118 and 138 ng/ml to 185 and 259 ng/ml, respectively) resulted in significant increases in pain detection and tolerance values for both nociceptive stimuli. Using electrical stimulation, methadone patients' pain tolerance values were lower than controls at 0 h, but higher than controls at 3 h; no significant differences in pain detection values were found. For the cold pressor test, methadone patients detected pain significantly earlier than controls at 0 h, and were also substantially less pain tolerant than controls at both 0 and 3 h. There were no significant differences in pain detection values between the two groups at 3 h. Pain tolerance to pain detection ratios for methadone patients were significantly lower than controls for the cold pressor test at 0 and 3 h, and for electrical stimulation at 0 h only. In summary, the relative pain sensitivity of methadone maintenance patients is determined by the nature of the nociceptive stimulus (e.g. cold pressor test versus electrical stimulation), the plasma methadone concentration (trough versus peak plasma concentration), and whether thresholds are determined for detection of pain or pain tolerance. Although responding to changes in plasma methadone concentration, maintenance patients are markedly hyperalgesic to pain induced by the cold pressor test.

Adult↗
PubMed2001

Yeast mating: getting close to membrane merger.

The machinery that mediates membrane fusion during yeast mating has remained elusive. But now a post-genomics approach has provided a powerful wedge into this difficult problem: a pheromone-induced multimembrane spanning protein has been identified as a key part of the mating machine.

Cell Adhesion↗
PubMed2001

Modification of d-amphetamine-induced responses by baclofen in rats.

RATIONALE: d-Amphetamine is known to have effects on heart rate, body temperature and locomotor activity. However, it is not known if GABAB receptor stimulation modifies these actions of d-amphetamine. OBJECTIVES: Using telemetry recordings, this study examined the interactions between the GABAB receptor agonist baclofen and d-amphetamine, on heart rate responses, body temperature and locomotor activity, and whether these effects could be blocked by the GABAB receptor antagonist SCH 50911. METHODS: Rats were prepared with telemetry implants, which allowed continuous monitoring of heart rate, core temperature and spontaneous locomotor activity. Drugs were subsequently administered subcutaneously to the animals for simultaneous recording over a period of 180 min. RESULTS: d-Amphetamine alone (0.3, 1.0 and 3.0 mg/kg) produced a dose-related increase in heart rate, but was without any effect on body temperature, whilst at 1.0 mg/kg, it significantly increased locomotor activity. Baclofen increased heart rate without affecting locomotor activity, and, at the highest dose of 10.0 mg/kg, it induced a significant reduction in body temperature. Graded doses of baclofen (3.0-10.0 mg/kg), when co-administered with d-amphetamine (1.0 mg/kg), did not modify the d-amphetamine-induced increase in heart rate, but the combination produced significant reductions of body temperature. The latter was only partially reversed by the GABAB receptor antagonist SCH 50911 (10.0 mg/kg). By contrast, the increase in locomotor activity by d-amphetamine was markedly blocked by baclofen in a dose-related manner, and this effect was abolished by SCH 50911 (10.0 mg/kg). SCH 50911 alone at doses of 3.0, 6.0 and 10.0 mg/kg had no effect on temperature or locomotor activity. Heart rate was increased significantly, but the magnitude of change was small. CONCLUSIONS: The results of the present study suggest that stimulation of GABAB receptors by baclofen completely blocks the locomotor stimulatory effects of d-amphetamine. Baclofen did not significantly modify the increase in heart rate produced by d-amphetamine and decreased body temperature, both alone and in combination with d-amphetamine. GABAB receptor ligands may well have potential as pharmacotherapies in the treatment of amphetamine abuse and dependence.

Animals↗