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Biomedical subjects

N Cox

Publications and source records attributed to N Cox.

At least 19 recordsLinked to original sources
PubMed2006

KCNMB1 regulates surface expression of a voltage and Ca2+-activated K+ channel via endocytic trafficking signals.

Voltage-dependent and calcium-activated K(+) (MaxiK, BK) channels are ubiquitously expressed and have various physiological roles including regulation of neurotransmitter release and smooth muscle tone. Coexpression of the pore-forming alpha (hSlo) subunit of MaxiK channels with a regulatory beta1 subunit (KCNMB1) produces noninactivating currents that are distinguished by high voltage/Ca(2+) sensitivities and altered pharmacology [McManus OB, Helms LM, Pallanck L, Ganetzky B, Swanson R, Leonard RJ (1995) Functional role of the beta subunit of high conductance calcium-activated potassium channels. Neuron 14:645-650; Wallner M, Meera P, Ottolia M, Kaczorowski G, Latorre R, Garcia ML, Stefani E, Toro L (1995) Characterization of and modulation by a beta-subunit of a human maxi K(Ca) channel cloned from myometrium. Receptors Channels 3:185-199]. We now show that beta1 can regulate hSlo traffic as well, resulting in decreased hSlo surface expression. beta1 subunit expressed alone is able to reach the plasma membrane; in addition, it exhibits a distinct intracellular punctated pattern that colocalizes with an endosomal marker. Coexpressing beta1 subunit with hSlo, switches hSlo's rather diffuse intracellular expression to a punctate cytoplasmic localization that overlaps beta1 expression. Furthermore, coexpressed beta1 subunit reduces steady-state hSlo surface expression. Site-directed mutagenesis underscores a role of a putative endocytic signal at the beta1 C-terminus in the control of hSlo surface expression. We propose that aside from its well-established role as regulator of hSlo electrical activity, beta1 can regulate hSlo expression levels by means of an endocytic mechanism. This highlights a new beta1 subunit feature that regulates hSlo channels by a trafficking mechanism.

Cell Line↗
PubMed2006

Non-invasive multislice computed tomography coronary angiography for imaging coronary arteries, stents and bypass grafts.

Abstract Multislice computed tomography (MSCT) is evolving rapidly and available data suggest that MSCT coronary angiography may be a reliable and accurate non-invasive imaging modality of coronary arteries. Current generations of MSCT scanners have high sensitivity and specificity for diagnosing native coronary artery disease and coronary bypass graft occlusion. The performance of MSCT in the evaluation of stent patency is still being assessed. In comparison with conventional selective coronary angiography (SCA), MSCT is non-invasive, cheaper and it has the advantages of imaging plaque compositions as well as assessment of luminal patency. Nevertheless, the role of MSCT in the management of coronary artery disease is yet to be fully defined.

Coronary Angiography↗
PubMed2005

Choice and availability of takeaway and restaurant food is not related to the prevalence of adult obesity in rural communities in Australia.

OBJECTIVES: To establish whether choice and availability of takeaway and restaurant food consumption are associated with increased obesity. DESIGN: Crossroads Undiagnosed Disease Study: a cross-sectional study undertaken between June 2001 and March 2003. SETTING: A regional centre and six shire capitals of variables size in rural Victoria, Australia. PARTICIPANTS: In total, 1454 residents of randomly selected households. MEASUREMENTS: Obesity (by body mass index (BMI) or waist circumference), weekly recreational activity, self-reported frequency of takeaway consumption, number of local takeaway and restaurant food outlets in the area. RESULTS: The prevalence of obesity ranged from 25.5-30.8% and was higher than the general Australian population among both men and women. Those in the regional centre were less likely than those in large and small shire capitals to participate in recreational activity of 150 min or more (39.7 vs 48.4%, 46.0% respectively, P=0.023) and yet reported better access to facilities and amenities for physical activity. Recreational activity of > or =150 min/week was associated with 0.75 (0.58-0.97) fold less risk of obesity. BMI was unrelated to takeaway consumption. Waist circumference was significantly lower among those eating no takeaways, but similar whether takeaways were consumed <1/month or > or =1/week. Increased takeaway consumption was associated with increased consumption of higher fat preparations of dairy and meat products. Availability of takeaway outlets and restaurants was unrelated to obesity. CONCLUSION: The obesity epidemic exists among those without significant consumption of or availability to takeaway foods. In a setting of easy availability of food, the obesity epidemic relates strongly to reduced physical activity, but not to consumption of takeaway food.

Age Factors↗
PubMed2004

Genome scan for loci linked to mite sensitivity: the Collaborative Study on the Genetics of Asthma (CSGA).

Mite sensitivity has been reported to be a major risk factor for asthma. As part of the Collaborative Study on the Genetics of Asthma (CSGA), a genome scan using mite reactivity (Dermatophagoides Pteronyssinus (Der p) and Dermatophagoides farinae (Der f)) as the phenotype was conducted. In 287 CSGA families, 122 were informative for linkage. Evidence supporting linkage was observed for regions on chromosome 19 (D19S591, lod=2.43, P=0.0008; D19S1037, lod=1.57, P=0.007) and chromosome 20 (D20S473/D20S604, lod=1.41, P=0.01). All three ethnic groups appeared to contribute to the evidence for linkage on chromosome 20. African-American families gave strongest support for linkage on chromosomes 3 (D3S2409, lod=1.33, P=0.01), 12 (D12S373, lod=1.51, P=0.008) and 18 (ATA82B02, lod=1.32, P=0.01). Caucasian families showed strong evidence for linkage on chromosome 19 (D19S591, lod=3.51, P=0.00006). Hispanic families supported linkage on chromosomes 11 (D11S1984, lod=1.56, P=0.007), 13 (D13S787, lod=1.30, P=0.01) and 20 (D20S470, lod=1.71, P=0.005). These results suggest that multiple genes may be involved in controlling skin reactivity to Dermatophoigoies.

Animals↗
PubMed2004

A randomised placebo controlled 12 week trial of budesonide and prednisolone in rheumatoid arthritis.

OBJECTIVES: To compare budesonide, a locally acting glucocorticoid with minimal systemic exposure, with conventional glucocorticoid treatment and placebo in rheumatoid arthritis. METHODS: A double blind, randomised, controlled trial over 12 weeks in 143 patients with active rheumatoid arthritis, comparing budesonide 3 mg daily, budesonide 9 mg daily, prednisolone 7.5 mg daily, and placebo. Particular attention was paid to the pattern of clinical response and to changes in the four week period following discontinuation of treatment. RESULTS: There were improvements in tender joint count and swollen joint count on budesonide 9 mg compared with placebo (28% for tender and 34% for swollen joint counts, p<0.05). Prednisolone 7.5 mg gave similar results, while budesonide 3 mg was less effective. ACR20 response criteria were met by 25% of patients on placebo, 22% on budesonide 3 mg, 42% on budesonide 9 mg, and 56% on prednisolone 7.5 mg. A rapid and significant reduction in symptoms and signs in response to budesonide 9 mg and prednisolone 7.5 mg was evident by two weeks and maximal at eight weeks. There was no evidence that budesonide provided a different pattern of symptom control from prednisolone, or that symptoms became worse than placebo treatment levels after discontinuation of glucocorticoid treatment. Adverse effects attributable to glucocorticoids were equally common in all groups. CONCLUSIONS: The symptomatic benefits of budesonide 9 mg and prednisolone 7.5 mg are achieved within a short time of initiating treatment, are maintained for three months, and are not associated with any rebound in symptoms after stopping treatment.

Adult↗
PubMed2004

Quality of life in paediatric lupus.

Paediatric systemic lupus erythematosus (SLE) is associated with significant morbidity and has biopsychosocial implications resulting from the disease and its treatment. The aim of this study was to identify domains of quality of life (QOL) impacted by SLE in children. Children with SLE and their parents were asked a single open-ended question related to lupus. Themes derived from children's responses focused primarily on coping and maintaining control of their life despite SLE. Themes from the parents' responses were twofold: a) efforts to cope with their child having SLE; and b) appreciation/sadness in connection with their children's coping process. Qualitative exploration of different facets of QOL in these children is critical for the understanding of specific factors that assist/ease the coping process and formulating interventions for improving children's/family's self-efficacy and disease management.

Adaptation, Psychological↗
PubMed2003

Pathogenicity and antigenicity of a new influenza A (H5N1) virus isolated from duck meat.

Avian influenza A viruses are the ancestral origin of all human influenza viruses. The outbreak of highly pathogenic (HP) avian H5N1 in Hong Kong in 1997 highlighted the potential of these viruses to infect and cause severe disease in humans. Since 1999, HP H5N1 viruses were isolated several times from domestic poultry in Asia. In 2001, a HP H5N1 virus, A/Duck/Anyang/AVL-1/2001 (Dk/Anyang), was isolated from imported frozen duck meat in Korea. Because of this novel source of HP H5N1 virus isolation, concerns were raised about the potential for human exposure and infection; we therefore compared the Dk/Anyang virus with HP H5N1 viruses isolated from humans in 1997 in terms of antigenicity and pathogenicity for mammals. At high doses, Dk/Anyang virus caused up to 50% mortality in BALB/c mice, was isolated from the brains and lymphoid organs of mice, and caused lymphopenia. Overall Dk/Anyang virus was substantially less pathogenic for mice than the H5N1 virus isolated from a fatal human case in 1997. Likewise, Dk/Anyang virus was apathogenic for ferrets. Dk/Anyang virus was antigenically distinguishable by hemagglutination-inhibition (HI) assay from human H5N1 viruses isolated in 1997 and avian H5N1 viruses isolated in 2001 in Hong Kong. Nevertheless, prior infection with Dk/Anyang virus protected mice from death after secondary infection with HP human H5N1 viruses. These results indicate that compared with HP human H5N1 viruses, Dk/Anyang virus is substantially less pathogenic for mammalian species. Nevertheless, the novel source of isolation of this avian H5N1 virus must be considered when evaluating the potential risk to public health.

Animals↗
PubMed2003

Spectrofluorometric analysis of phylloerythrin (phytoporphyrin) in plasma and tissues from sheep suffering from facial eczema.

AIMS: To study the increase in phylloerythrin concentration in plasma and the disposition of phylloerythrin in skin and other tissues of sheep in which the hepatogenous photosensitisation,facial eczema, had been experimentally induced by dosing with the mycotoxin, sporidesmin. Spectroscopic differences between plasma and skin measurements of animals kept inside and outside after dosing were also studied in order to establish whether phylloerythrin undergoes photodegradation when exposed to sunlight. METHODS: Twenty-six Romney x Polled Dorset (25-30 kg)weaned female lambs were purchased from a commercial flock in the Waikato region, New Zealand. Twenty-two of these lambs were dosed with 0.25 mg sporidesmin/kg liveweight on each of two consecutive days (Days -1 and 0); the remaining four lambs served as controls. Both sporidesmin-dosed lambs and controls were randomly divided into two penned groups, one group housed inside in a darkened room and the others outside, exposed to natural sunlight. The lambs were fed green lucerne pellets and lucerne chaff ad libitum for 10 days prior to dosing and until Day 12 after the first dose; thereafter, all the lambs were fed fresh, cut grass (mainly ryegrass) ad libitum, until the end of the experimental period on Day 26. Plasma samples collected on Days -2, 7, 10, 12, 14, 17, 20 and 25were analysed for gamma glutamyltransferase (GGT) activity, bilirubin concentration, and the fluorescence spectrum of phylloerythrin. Spectrofluorometric analysis of phylloerythrin in skin was performed in vivo on the same days, using an external fiber-optic probe. RESULTS: Eight of 11 lambs (73%) kept outside after sporidesmin dosing became photosensitised during the experimental period. None of the sporidesmin-dosed animals kept inside showed clinical signs of photosensitisation. The GGT activity in plasma increased exponentially during the experimental period in all sporidesmin-dosed animals until it reached a plateau. All plasma obtained from sporidesmin-dosed sheep had spectral characteristics similar to those of phylloerythrin, namely a peak in the excitation spectrum at 422 nm and strong emission band at 650 (SE 1) and 709 (SE 1) nm. The fluorescence under excitation at 422 nm of phylloerythrin added to plasma from control lambs had identical peaks. Emission spectra obtained from plasma from healthy sheep without addition of phylloerythrin showed either no fluorescence or minor fluorescence at around 671 nm. Fluorescence in skin of sporidesmin-dosed animals had similar spectra to that in plasma. The appearance of the phylloerythrin-like spectra occurred 2-3 days later in the skin than in plasma, and phylloerythrin in sunlight-exposed skin did not suffer photodegradation during the course of the study. CONCLUSION: Plasma concentrations of phylloerythrin in healthy sheep were <0.1 micromol/l, and clinical signs of photosensitisation were not evident until concentrations exceeded 0.3 micromol/l. Plasma concentrations of phylloerythrin rose as high as 4.9 micromol/l in some animals. The concentration of phylloerythrin in skin began increasing 2-3 days later than that in blood. Hepatogenous photosensitisation can be diagnosed by analysis of plasma phylloerythrin concentrations using a spectroscopic method.

Journal Article↗
PubMed2003

Pathogenesis of and immunity to a new influenza A (H5N1) virus isolated from duck meat.

The outbreak of avian influenza H5N1 in Hong Kong in 1997 raised concerns about the potential for the H5 subtype to cause a human pandemic. In 2001 a new H5N1 virus, A/Duck Meat/Anyang/AVL-1/2001 (A/Dkmt), was isolated from imported duck meat in Korea. The pathogenesis of this virus was investigated in mice. A/Dkmt virus had low infectivity but was lethal for mice at high doses, and at lethal doses, the virus replicated in the brains of infected mice. A/Dkmt virus cross-reacted poorly with ferret antisera raised against human H5N1 viruses, but prior infection with A/Dkmt virus protected mice from death after secondary infection with human H5N1 virus.

Animals↗
PubMed2003

Safety evaluation in chickens of candidate human vaccines against potential pandemic strains of influenza.

Two candidate formalin-inactivated vaccines, made from high-growth reassortant viruses with the HA and NA genes from avian viruses in a background of genes derived from A/Puerto Rico/8/34 (PR8), were prepared against H5N1 and H9N2 subtypes (designated as H5N1/PR8 and H9N2/PR8, respectively). These viruses bear the genotypes, antigenicity, and attenuation in mouse models that are desirable in candidate vaccines. The pathogenicity of the newly generated avian-human reassortant vaccine viruses was also evaluated in chickens. Neither H5N1/PR8 nor H9N2/PR8 were highly pathogenic for chickens. No clinical signs, gross legions, or histological lesions were observed in chickens that were administered H5N1/PR8 either intranasally (i.n.) or intravenously (i.v.), and virus was not detected in oropharyngeal or cloacal swabs. When H9N2/PR8 was administered i.n., no clinical signs, gross lesions, or histological lesions were observed and no virus was detected in cloacal swabs. However, virus was isolated at low titer from oropharyngeal swabs of all eight chickens. Although no clinical signs were observed when H9N2/PR8 was administered i.v., mild tracheitis was seen in one of two chickens. Moderate amounts of antigen were observed in tracheal respiratory epithelium, and low titers of virus were recovered from oropharyngeal and cloacal swabs of some chickens. In summary, both reassortant vaccine viruses replicated poorly in chickens. These studies suggest that these candidate vaccine viruses carry a low risk of transmission to chickens.

Animals↗
PubMed2002

Molecular changes associated with the transmission of avian influenza a H5N1 and H9N2 viruses to humans.

In order to identify molecular changes associated with the transmission of avian influenza A H5N1 and H9N2 viruses to humans, the internal genes from these viruses were compared to sequences from other avian and human influenza A isolates. Phylogenetically, each of the internal genes of all sixteen of the human H5N1 and both of the H9N2 isolates were closely related to one another and fell into a distinct clade separate from clades formed by the same genes of other avian and human viruses. All six internal genes were most closely related to those of avian isolates circulating in Asia, indicating that reassortment with human strains had not occurred for any of these 18 isolates. Amino acids previously identified as host-specific residues were predominantly avian in the human isolates although most of the proteins also contained residues observed previously only in sequences of human influenza viruses. For the majority of the nonglycoprotein genes, three distinct subgroups could be distinguished on bootstrap analyses of the nucleotide sequences, suggesting multiple introductions of avian virus strains capable of infecting humans. The shared nonglycoprotein gene constellations of the human H5N1 and H9N2 isolates and their detection in avian isolates only since 1997 when the first human infections were detected suggest that this particular gene combination may confer the ability to infect humans and cause disease. J. Med. Virol. 66:107-114, 2002. Published 2002 Wiley-Liss, Inc.

Animals↗
PubMed2002

Transmission disequilibrium mapping at the serotonin transporter gene (SLC6A4) region in autistic disorder.

The serotonin transporter gene (SLC6A4, MIM 182138) is a candidate gene in autistic disorder based on neurochemical, neuroendocrine studies and the efficacy of potent serotonin transporter inhibitors in reducing ritualistic behaviors and related aggression. An insertion/deletion polymorphism (5-HTTLPR) in the promoter region and a variable number of tandem repeat polymorphism (VNTR) in the second intron, were previously identified and suggested to modulate transcription. Six previous family-based association studies of SLC6A4 in autistic disorder have been conducted, with four studies showing nominally significant transmission disequilibrium and two studies with no evidence of nominally significant transmission disequilibrium. In the present study, TDT was conducted in 81 new trios. A previous finding of transmission disequilibrium between a haplotype consisting of the 5-HTTLPR and intron 2 VNTR was replicated in this study, but not preferential transmission of 5-HTTLPR as an independent marker. Because of inconsistent transmission of 5-HTTLPR across studies, SLC6A4 and its flanking regions were sequenced in 10 probands, followed by typing of 20 single nucleotide polymorphisms (SNPs) and seven simple sequence repeat (SSR) polymorphisms in 115 autism trios. When individual markers were analyzed by TDT, seven SNP markers and four SSR markers (six SNPs, 5-HTTLPR and the second intron VNTR from promoter 1A through intron 2 of SLC6A4, one SSR from intron 7 of SLC6A4, one SNP from the bleomycin hydrolase gene (BLMH, MIM 602403) and one SSR telomeric to BLMH) showed nominally significant evidence of transmission disequilibrium. Four markers showed stronger evidence of transmission disequilibrium (TDT(max) P = 0.0005) than 5-HTTLPR.

Autistic Disorder↗
PubMed2002

Which patients stop working because of rheumatoid arthritis? Results of five years' follow up in 732 patients from the Early RA Study (ERAS).

OBJECTIVES: To assess the occurrence and prognostic factors for the ability to maintain paid work in patients with rheumatoid arthritis (RA). SETTING: Inception cohort of patients with RA recruited from rheumatology departments in nine NHS Hospital Trusts in England. PATIENTS: All consecutive patients with RA of less than two years' duration, before any second line (disease modifying) drug treatment, and followed up for five years. METHODS: Clinical, laboratory, and radiological assessments, and all treatments were recorded prospectively using a standardised format at presentation and yearly. OUTCOME MEASURES: Changes in, and loss of paid work by five years' follow up. RESULTS: 732 patients completed the five year follow up. 353/721 (49%) were gainfully employed at the onset of RA, 211 (60%) were still working at five years, 104 (29%) stopped because of the disease, and 31 (9%) retired for reasons other than RA. Work disability at five years was more likely in manual workers (odds ratio (OR) 2.3, 95% confidence interval (CI) 1.4 to 3.8) and worse baseline Health Assessment Questionnaire (HAQ>1.5, OR 2.26, 95% CI 1.38 to 3.7). In combination with other baseline variables (erythrocyte sedimentation rate, sex, age of onset, and radiological erosions), employment outcome was predicted in 78% using multivariate analysis. CONCLUSIONS: Nearly half of the patients with RA were in paid employment at onset, work disability was an adverse outcome for a third of these patients by five years, and manual work and high baseline HAQ were important predictors for this. These details are likely to be useful to clinicians, health professionals, and patients in order to plan medical, orthopaedic, and remedial treatments in early RA. Future disease modifying treatments could be compared with this cohort of patients who were treated with conventional second line drugs.

Adult↗
PubMed2001

The occurrence of hepatitis A and astroviruses in selected river and dam waters in South Africa.

Over a period of one year (June 1997-May 1998) samples of surface waters, used for domestic and recreational purposes, were collected weekly from the same sites on the Klip River and Vaal Dam, Gauteng, South Africa. Sensitive and specific reverse transcriptase-polymerase chain reaction-oligonucleotide probe assays were used to detect HAV and HAstV RNA in concentrates of the water and infectious virus in cell cultures infected with the water concentrates. HAV was detected in 18 (35.3%) of the river and 19 (37.3%) of the dam water samples, often in association with the RNA from other enteric viruses. HAstV was detected less frequently and was present in 11 (21.6%) of the river and 3 (5.9%) of the dam water samples. A seasonal pattern was noted for HAV but not for HAstV. Cell culture amplification in a variety of carefully selected cell culture systems enhanced the detection of both viruses. Infectious viruses were detected in dam water samples where microbiological indicators of faecal pollution were absent or within acceptable limits. The presence of these viruses in the dam and river water could pose a potential health risk for people using these waters for domestic or recreational purposes.

Adult↗
PubMed2001

Myocardial infarction due to saphenous vein graft compression by an extracardiac mass.

We present an unusual case of a patient with an inferior infarct caused by saphenous vein graft compression by an extracardiac malignant spindle cell tumour, a mechanism of myocardial ischaemia rarely described. This case also illustrates how chest X-ray and angiography can be useful for making an early diagnosis of a cardiac mass.

Journal Article↗
PubMed2001

Infection of a child in Hong Kong by an influenza A H3N2 virus closely related to viruses circulating in European pigs.

Influenza virus A/Hong Kong/1774/99, isolated from a young child with mild influenza, was shown to be similar in its antigenic and genetic characteristics to H3N2 viruses circulating in pigs in Europe during the 1990s and in particular to be closely related to viruses isolated from two children in the Netherlands in 1993. Similar viruses had previously not been identified outside Europe. Although there is little evidence as to how the child contracted the infection, it appears likely that pigs in southern China were the source of infection. Characteristics shared with the European swine viruses include resistance to the anti-influenza drugs amantadine and rimantadine. Thus not only does this incident once again highlight the potential of pigs as a source of novel human influenza viruses, but also indicates the potential for emergence of amantadine-resistant human viruses.

Amantadine↗