Maybe we're disinfecting ourselves too much.
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Biomedical subjects
Publications and source records attributed to S Wilson.
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OBJECTIVE: To identify and qualitatively synthesise the findings from all studies that have examined the performance and effect of near patient tests in the primary care setting. DESIGN: Systematic review of published and unpublished research 1986-99. MAIN OUTCOME MEASURES: Test performance characteristics, measures of effect on clinical practice or patient outcome. RESULTS: 101 relevant publications were identified. The general quality of these papers was low, and consequently only 32 papers were assessed in detail. Although these papers gave some indication of the value of near patient testing in areas such as anticoagulation monitoring and group A beta haemolytic streptococcus testing, the research raised many more questions than it answered. Almost no reports were found of unbiased assessment of the effect of near patient tests in primary care on patient outcomes, organisational outcomes, or cost. CONCLUSIONS: Available research provides little evidence to guide the expansion of use of near patient testing in primary care. Further research is needed in areas of clinical practice where near patient tests might be most beneficial.
Urotensin-II (U-II) is a vasoactive 'somatostatin-like' cyclic peptide which was originally isolated from fish spinal cords, and which has recently been cloned from man. Here we describe the identification of an orphan human G-protein-coupled receptor homologous to rat GPR14 and expressed predominantly in cardiovascular tissue, which functions as a U-II receptor. Goby and human U-II bind to recombinant human GPR14 with high affinity, and the binding is functionally coupled to calcium mobilization. Human U-II is found within both vascular and cardiac tissue (including coronary atheroma) and effectively constricts isolated arteries from non-human primates. The potency of vasoconstriction of U-II is an order of magnitude greater than that of endothelin-1, making human U-II the most potent mammalian vasoconstrictor identified so far. In vivo, human U-II markedly increases total peripheral resistance in anaesthetized non-human primates, a response associated with profound cardiac contractile dysfunction. Furthermore, as U-II immunoreactivity is also found within central nervous system and endocrine tissues, it may have additional activities.
A fusion protein (beta-arrestin-1-green fluorescent protein (GFP)) was constructed between beta-arrestin-1 and a modified form of the green fluorescent protein from Aequorea victoria. Expression in HEK293 cells allowed immunological detection of an 82-kDa cytosolic polypeptide with antisera to both beta-arrestin-1 and GFP. Transient expression of this construct in HEK293 cells stably transfected to express the rat thyrotropin-releasing hormone receptor-1 (TRHR-1) followed by confocal microscopy allowed its visualization evenly distributed throughout the cytoplasm. Addition of thyrotropin-releasing hormone (TRH) caused a profound and rapid redistribution of beta-arrestin-1-GFP to the plasma membrane followed by internalization of beta-arrestin-1-GFP into distinct, punctate, intracellular vesicles. TRH did not alter the cellular distribution of GFP transiently transfected into these cells nor the distribution of beta-arrestin-1-GFP following expression in HEK293 cells lacking the receptor. To detect potential co-localization of the receptor and beta-arrestin-1 in response to agonist treatment, beta-arrestin-1-GFP was expressed stably in HEK293 cells. A vesicular stomatitis virus (VSV)-tagged TRHR-1 was then introduced transiently. Initially, the two proteins were fully resolved. Short term exposure to TRH resulted in their plasma membrane co-localization, and sustained exposure to TRH resulted in their co-localization in punctate, intracellular vesicles. In contrast, beta-arrestin-1-GFP did not relocate or adopt a punctate appearance in cells that did not express VSV-TRHR-1. Reciprocal experiments were performed, with equivalent results, following transient expression of beta-arrestin-1 into cells stably expressing VSVTRHR-1-GFP. These results demonstrate the capacity of beta-arrestin-1-GFP to interact with the rat TRHR-1 and directly visualizes their recruitment from cytoplasm and plasma membrane respectively into overlapping, intracellular vesicles in an agonist-dependent manner.
The underlying causes of obesity are poorly understood but probably involve complex interactions between many neurotransmitter and neuropeptide systems involved in the regulation of food intake and energy balance. Three pieces of evidence indicate that the neuropeptide melanin-concentrating hormone (MCH) is an important component of this system. First, MCH stimulates feeding when injected directly into rat brains; second, the messenger RNA for the MCH precursor is upregulated in the hypothalamus of genetically obese mice and in fasted animals; and third, mice lacking MCH eat less and are lean. MCH antagonists might, therefore, provide a treatment for obesity. However, the development of such molecules has been hampered because the identity of the MCH receptor has been unknown until now. Here we show that the 353-amino-acid human orphan G-protein-coupled receptor SLC-1 expressed in HEK293 cells binds MCH with sub-nanomolar affinity, and is stimulated by MCH to mobilize intracellular Ca2+ and reduce forskolin-elevated cyclic AMP levels. We also show that SLC-1 messenger RNA and protein is expressed in the ventromedial and dorsomedial nuclei of the hypothalamus, consistent with a role for SLC-1 in mediating the effects of MCH on feeding.
The Schizosaccharomyces pombe homologue of Mre11, Rad32, is required for repair of UV- and ionising radiation-induced DNA damage and meiotic recombination. In this study we have investigated the role of Rad32 and other DNA damage response proteins in non-homologous end joining (NHEJ) and telomere length maintenance in S.pombe. We show that NHEJ in S.pombe occurs by an error-prone mechanism, in contrast to the accurate repair observed in Saccharomyces cerevisiae. Deletion of the rad32 gene results in a modest reduction in NHEJ activity and the remaining repair events that occur are accurate. Mutations in two of the phosphoesterase motifs in Rad32 have no effect on the efficiency or accuracy of end joining, suggesting that the role of Rad32 protein may be to recruit another nuclease(s) for processing during the end joining reaction. We also analysed NHEJ in other DNA damage response mutants and showed that the checkpoint mutant rad3-d and two recombination mutants defective in rhp51 and rhp54 (homologues of S.cerevisiae RAD51 and RAD54, respectively) are not affected. However disruption of rad22, rqh1 and rhp9 / crb2 (homologues of the S.cerevisiae RAD52, SGS1 and RAD9 genes) resulted in increased NHEJ activity. Telomere lengths in the rad32, rhp9 and rqh1 null alleles were reduced to varying extents intermediate between the lengths observed in wild-type and rad3 null cells.
In order to minimize the effects of porcine reproductive and respiratory syndrome (PRRS) on stillbirth, mummification, and neonatal mortality in swine herds, many producers have vaccinated their herds using a modified-live virus vaccine. The purpose of this study was to determine the association of the PRRS modified-live vaccine and reproductive performance by stage of gestation when the vaccine was administered. A total of 47 swine herds from Ontario and Manitoba, Canada, and from the mid-western USA were included in the study. Participating farms had vaccinated all of their sows at one point in time when they used the vaccine for the first time. The reproductive performance of sows that farrowed in the year prior to use of the vaccine was compared to that of sows vaccinated in each of five stages of gestation and in the gestation that followed the initial use of the vaccine. Sows vaccinated at any time during gestation had a reduced number of pigs born alive, a reduced number of pigs weaned per litter, and increased number of stillborn pigs and an increased number of mummified pigs compared to the sows that farrowed prior to use of the vaccine. The largest association was seen in sows that were vaccinated in the last four weeks of gestation. The largest losses were observed in those herds that were vaccinated concurrently with the initial PRRS herd outbreak. These results suggest that the modified-live vaccine should only be administered to non-gestating sows.
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To assess whether oral vaccination against human papillomavirus (HPV) may be feasible, we administered HPV virus-like particles (VLPs) to mice by gavage. Enzyme-linked immunosorbent assay (ELISA) results indicated that serum anti-VLP immunoglobulin G (IgG) and IgA antibodies were induced after oral vaccination, and these responses demonstrated antigenic specificities that were conformationally dependent and restricted according to HPV genotype. Importantly, orally induced postimmune sera were found to neutralize HPV-11 virions in vitro. These results indicated that the VLPs were antigenically stable in the environment of the gastrointestinal tract and were able to engage in potentially useful immune system interactions. These findings support the concept of oral vaccination against anogenital HPV disease, and suggest the possibility that this may be a useful approach to the immunization of large populations against cervical cancer and other HPV associated diseases.
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Antigen specific llama VHH antibody fragments were compared to antigen specific mouse monoclonal antibodies with respect to specificity, affinity and stability. The llama VHH antibody fragments and the mouse monoclonal antibodies investigated were shown to be highly specific for the protein antigen hCG or the hapten antigen RR-6. The affinity of the interaction between monovalent llama VHH antibody fragments and their antigen is close to the nanomolar range, similar to the bivalent mouse monoclonal antibodies studied. Llama VHH antibody fragments are similar to mouse monoclonal antibodies with respect to antigen binding in the presence of ammonium thiocyanate and ethanol. The results show that relative to antigen specific mouse monoclonal antibodies, antigen specific llama VHH fragments are extremely temperature stable. Two out of six llama VHHs are able to bind antigen specifically at temperatures as high as 90 degrees C, whereas four out of four mouse monoclonal antibodies are not functional at this temperature. Together with the finding that llama VHH fragments can be produced at high yield in Saccharomyces cerevisiae, these findings indicate that in the near future antigen specific llama VHH fragments can be used in for antibodies unexpected products and processes.
OBJECTIVES: To measure GABA(A) benzodiazepine receptor sensitivity in patients taking benzodiazepines and compare with matched controls. METHODS: Seven patients who were on prescribed benzodiazepines for an anxiety disorder or insomnia were recruited from general practice and an adult mental health service outpatient clinic. They were matched with seven volunteers. All subjects received an intravenous injection of midazolam 50 microgram/kg in 10 ml normal saline over 10 min. Objective responses to midazolam were assessed using saccadic eye movement velocity slowing and subjective assessments using visual analogue scales. Measurements were recorded for 120 min and plasma midazolam concentrations obtained at 15-min intervals post-infusion to 120 min. Ratios of pharmacodynamic/pharmacokinetic effects were obtained for each individual to estimate GABA(A) benzodiazepine receptor sensitivity. RESULTS: Patients had an attenuated response to midazolam on both subjective and objective measures. GABA(A) benzodiazepine receptor sensitivity was significantly reduced in the patient group. CONCLUSIONS: Chronic treatment with benzodiazepines was associated with reduced effects of midazolam. Saccadic eye movement velocity was especially sensitive as a measure of attenuated response.
OBJECTIVE: This study was undertaken to compare the persistence of changes in estimated cerebral perfusion pressure and the resistance area product, an index of cerebrovascular resistance, in women with preeclampsia and women with eclampsia. STUDY DESIGN: The maternal middle cerebral artery was evaluated by transcranial Doppler ultrasonography in 6 patients with severe preeclampsia and 3 women with eclampsia, and cerebral blood flow velocities were determined. Estimated cerebral perfusion pressure was calculated according to the following equation: Estimated cerebral perfusion pressure = Mean cerebral blood flow velocity/(Mean cerebral blood flow velocity - Diastolic cerebral blood flow velocity) x (Mean blood pressure - Diastolic blood pressure). Because the diameters of the vessels could not be measured directly, an index of resistance was calculated according to the following equation: Resistance area product = Mean blood pressure/Mean cerebral blood flow velocity. We calculated an index of cerebral blood flow according to the following equation: Index = Estimated cerebral perfusion pressure/Resistance area product. Patients were reassessed at 24 and 48 hours after delivery. RESULTS: At the initial assessment the estimated cerebral perfusion pressure was higher in women with eclampsia than in those with severe preeclampsia. In addition, cerebrovascular resistance was significantly decreased in the eclampsia group, and it remained decreased as long as 4 days in 1 patient with eclampsia. CONCLUSIONS: Preeclampsia is associated with increases in cerebral perfusion pressure counterbalanced by increases in cerebrovascular resistance, with no change in cerebral blood flow. In eclampsia a significant increase in cerebral perfusion pressure occurs, but a significant fall in cerebrovascular resistance also occurs and a loss of autoregulation results in cerebral overperfusion similar to that of hypertensive encephalopathy. This may persist for as long as 4 days.
The study reported here investigated the interactions of successive infections and acquired resistance of pigs to challenge infections of Schistosoma japonicum. Two morphologically indistinguishable geographical isolates from China (from Anhui and Zhejiang provinces) were used for the infections. The worms of the two isolates were distinguishable by PCR-linked restriction fragment length polymorphism analysis of the nicotinamide adenine dinucleotide phosphate dehydrogenase I gene of the mitochondrial genome. Thirty-two pigs divided into seven groups were used in the experiment. Two groups received a single infection by either the Anhui or the Zhejiang isolate. In Challenge Groups 1, 4, 6, 8 and 12, a primary infection of the Zhejiang isolate was followed by a challenge infection with the Anhui isolate at week 1, 4, 6, 8 or 12 after the primary infection. In this way it was possible to determine whether worms recovered by perfusion originated from the primary or the challenge infection. Only the challenge infection at week 1 resulted in a higher worm burden when compared with a single primary infection with the Zhejiang isolate. The results showed that challenge worms were able to establish, and that the proportion of worms originating from challenge infection increased at the later challenge infections, however without an increase in the total number of worms. In addition, mixed pairs of the two isolates were found in all challenge-infected groups. The results indicate that pigs are able to mount a partial resistance against re-infection with S. japonicum by 4 weeks after a primary infection, but that worms of the challenge infections eventually replace the primary infection. The finding of mixed pairs of the two isolates indicates that worms of S. japonicum are either polygamous or able to wait in solitude for up to 12 weeks for a partner.
Two novel hypothalamic neuropeptides, orexin-A and -B, are suggested to regulate feeding. A single intracerebroventricular injection of orexin-A (23.4 nmol), administered 3 h into the light phase, increased feeding in satiated rats and prolonged feeding in fasted rats; it also increased feeding when given 6 h into, but not at the start of, the dark phase. An 8-day intracerebroventricular infusion with orexin-A (18 nmol/day) increased daytime feeding on days 2 and 8, but nocturnal feeding was reduced and there was no change in 24 h intake. Orexin-B had no effects. These results demonstrate a circadian variation in feeding responses to orexin-A.
The orexins are recently identified appetite-stimulating hypothalamic peptides. We used immunohistochemistry to map orexin-A and orexin-B immunoreactivity in rat brain, spinal cord, and some peripheral tissues. Orexin-A- and orexin-B-immunoreactive cell bodies were confined to the lateral hypothalamic area and perifornical nuclei. Orexin-A-immunoreactive fibers were densely distributed in the hypothalamus, septum, thalamus, locus coeruleus, spinal cord, and near the ventricles, but absent from peripheral sites investigated. In contrast, orexin-B-immunoreactive fibers were distributed sparsely in the hypothalamus. Orexin cells are strategically sited to contribute to feeding regulation, but their widespread projections suggest that orexins have other physiological roles.
Organochlorine contaminants (pesticides and individual polychlorinated biphenyl congeners, PCBs) were measured in Caspian (Phoca caspica) seal blubber and compared with concentrations in Harbour (Phoca vitulina) seal blubber. Concentrations of total dichlorodiphenyltrichloroethane (DDT) and its metabolites were significantly higher in Caspian seal than Harbour seal samples, whereas PCB congeners were significantly higher in Harbour than Caspian seals. Our finding suggests that Caspian seals are exposed to high levels of DDT pesticides. In contrast, PCBs are circulating in this population at much lower levels than in marine mammals from the North Sea.