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Biomedical subjects

N Cox

Publications and source records attributed to N Cox.

At least 19 recordsLinked to original sources
PubMed1996

The gene responsible for autosomal dominant Doyne's honeycomb retinal dystrophy (DHRD) maps to chromosome 2p16.

Degeneration in the macula region of the retina is a feature of a heterogeneous group of inherited, progressive disorders, causing blinding visual impairment. Autosomal dominant Doyne's honeycomb retinal dystrophy (DHRD) is characterised by the presence of drusen deposits at the level of Bruch's membrane in the macula and around the edge of the optic nerve head. We have studied 63 members of a large, nine-generation British pedigree by linkage analysis. Two-point analysis showed significant linkage to nine markers on the short arm of chromosome 2, a region overlapping that recently reported to be linked to Malattia leventinese. A maximum lod score (Zmax) of 7.29 (theta = 0.0) was obtained at marker locus D2S2251. Haplotype analysis of recombination events localised the disease to a 5 cM region between marker loci D2S2316 and D2S378. Striking clinical similarities between DHRD and the more common condition age-related macular degeneration (ARMD) suggest that the disease gene at this locus could be considered as the most likely candidate in future studies on ARMD.

Chromosome Mapping↗
PubMed1996

Comparison of US inactivated split-virus and Russian live attenuated, cold-adapted trivalent influenza vaccines in Russian schoolchildren.

In a blinded, placebo-controlled study, the reactogenicity, immunogenicity, and clinical efficacy of single doses of US inactivated split-virus and Russian live attenuated, cold-adapted influenza vaccines were compared in 555 schoolchildren in Vologda, Russia. Serial serum samples were collected and school absenteeism was assessed. Systemic reactions were rare, but local reactions (primarily erythema at the injection site) were observed in 27% of the inactivated vaccine group, and coryza (12%) and sore throat (8%) were observed in the attenuated vaccine group. At 4 weeks after vaccination a > or = 4-fold rise in titer of hemagglutination inhibition antibody to A (H1N1), A (H3N2), and B was noted, respectively, among 78%, 88%, and 53% of children who received inactivated vaccine and among 55%, 79%, and 30% of children who received attenuated vaccine. The vaccine efficacy for preventing school absenteeism due to respiratory illness during the period of peak influenza activity was 56% for inactivated vaccine and 47% for attenuated vaccine.

Antibodies, Viral↗
PubMed1995

Amantadine-resistant influenza A in nursing homes. Identification of a resistant virus prior to drug use.

BACKGROUND: Amantadine hydrochloride and rimantadine hydrochloride have been used for treatment and prevention of influenza A infection in nursing home residents. Outbreaks of influenza A (H3N2) virus infection occurred in three nursing homes in Yakima County, Washington, during January 1992. Amantadine was used for case treatment and prophylaxis in all three nursing homes. METHODS: Ten influenza A (H3N2) viruses isolated during the outbreaks were examined for resistance to amantadine and rimantadine by means of an enzyme immunoassay and by sequencing of the viral nucleic acid that encodes the transmembrane domain of the M2 protein. RESULTS: Five of the outbreak strains were resistant and had the same mutation (position 31, serine to asparagine) in the M2 protein. The resistant viruses included one that had been recovered prior to any use of amantadine and another that was recovered within 48 hours of the first drug administration. CONCLUSIONS: To our knowledge, this is the first report of influenza A virus with RNA sequence-documented resistance to amantadine and rimantadine without exposure to either drug, and the shortest reported period between institution of amantadine therapy and isolation of a resistant influenza A virus strain. These results suggest that surveillance for amantadine- and rimantadine-resistant influenza A is needed, because use of these drugs will probably increase.

Adult↗
PubMed1995

Outcome in patients who require a gastrostomy after stroke.

Dysphagia is common after a stroke and is associated with a poor outcome in terms of survival or functional recovery. Percutaneous gastrostomy (PG) provides reliable and safe nutrition for patients with neurological dysphagia in the short term but little is known about the the subsequent outcome in stroke patients. We reviewed the medical records of all stroke patients who had required a PG in four West Yorkshire hospitals over a 30-month period. All patients alive at the time of the study were contacted and functional status was recorded. Forty-one stroke patients had undergone PG and 37 records were obtained. There were 24 men and 13 women with a mean age of 74 years. Thirty-three patients had had a hemiplegia while four patients presented acutely with dysphagia but no hemiplegia (all had cerebral infarcts on CT scan). The timing of PG varied with a median time from stroke of 26 days (range 12-131). Complications include five chest infections ( < 1 week after PG), three local infections, two tubes pulled out and one perforation. Three patients died in the first 5 days after the PG. Thirty-one of the 37 patients had died at the time of the assessment, 21 during the original hospital admission. The median survival from the time of PG was 53 days (range 2-528) with only 12 patients surviving for more than 3 months. Six patients were alive at the time of the study and all but one were severely disabled (mean modified Barthel Index seven). There is no consensus about patients selection or timing of PG and our data should lead to more careful consideration of the risks and benefits of the procedure in stroke patients.

Aged↗
PubMed1995

Linkage of familial dysalbuminemic hyperthyroxinemia to the albumin gene in a large Amish kindred.

Familial dysalbuminemic hyperthyroxinemia (FDH) is the most common cause of inherited euthyroid hyperthyroxinemia in Caucasians. Transmitted as an autosomal dominant trait, it is always associated with high serum total T4 (TT4) and more rarely with elevated total T3 (TT3) and/or rT3 (TrT3) concentrations. Free T4, by dialysis, and TSH levels are normal, suggesting the presence of a T4-binding protein abnormality. The abnormal serum T4 carrier shares some physical and immunological properties with albumin, suggesting that it may be albumin itself. Here we show linkage between FDH and the albumin gene in a large Amish family of Swiss descent, using as markers a SacI polymorphism in the coding sequence of the albumin gene and the group-specific component (Gc) gene, located less than 1 centimorgan from the albumin gene. Blood samples were obtained from 160 members of this kindred, and 22 had FDH identified by the pattern of T4 binding to serum proteins separated by isoelectric focusing. Serum TT4 values were above the normal range in all subjects expressing the FDH phenotype, and TrT3 levels were above the normal range in only one half. TT4 concentrations correlated positively with TrT3 and TT3. All TT3 values were, however, within the normal range. Free T4 and TSH levels were normal, confirming the euthyroid state in these subjects. FDH was associated with the albumin SacI(+)/Gc 1S haplotype, yielding a LOD (logarithm of the odds ratio) score of 5.53, with a recombination frequency of 0. These data provide strong support that a variant albumin is the cause of FDH in this kindred.

Base Sequence↗
PubMed1995

[Influenza vaccination of children with hemophilia].

51 haemophilic children aged from 7 to 16 years was vaccinated against influenza in Paediatric Department of Haematology and Oncology in November and December of 1993. Each dose of subunit vaccine manufactured by Wyeth-USA, contained 15 micrograms of each haemagglutinin strains as recommended for the season. The antibody level was studied before and after influenza vaccination in vaccinated and control group as well. 5-time rise of geometric mean antibody titre was found for H1N1 and H3N2 antigens after vaccination of the children group. Slightly lower, 2.7-time rise of GMT was showed for HB haemagglutinin of influenza virus. There was no significant rise of GMT for any among three studied virus haemagglutinin.

Adolescent↗
PubMed1994

Sequential imputation for multilocus linkage analysis.

A Monte Carlo method called sequential imputation is proposed for multilocus likelihood computations. This method is most useful in mapping situations where the data consist of large pedigrees with substantial missing information and it is desirable to perform linkage analysis utilizing data from many polymorphic markers simultaneously. A pedigree example with 155 individuals, 9 loci, and 155,520 haplotypes is used for illustration.

Diabetes Mellitus, Type 2↗
PubMed1993

Genetic aspects of early childhood stuttering.

Although stuttering has long been acknowledged as a familial disorder, the nature of a genetic component remains unclear. Most previous data used in genetic studies were obtained primarily from adults who stutter and may be biased in several respects. The purpose of this investigation was to quantify the frequency of stuttering in relatives of preschool-age children who stutter, and who were first seen close to the onset of the disorder. Detailed pedigrees (family trees), including first-, second-, and third-degree relatives, were obtained from parents of 69 children who stuttered. We found, as have previous studies, that more male than female relatives ever stuttered, but that female subjects who stuttered had more female relatives who ever stuttered than did male subjects. In order to identify the genetic model most consistent with the observed patterns of stuttering transmission, we conducted segregation analyses. Results from these analyses suggest that transmission of a single major genetic locus increasing the liability to stuttering best accounts for the transmission of stuttering in families of preschool-age children who stutter.

Child↗
PubMed1993

Efficacy of live attenuated and inactivated influenza vaccines in schoolchildren and their unvaccinated contacts in Novgorod, Russia.

Children aged 7-14 years in Novgorod, Russia, were given Russian live cold-adapted or inactivated influenza vaccines or placebo over a 2-year period. Schools were randomly assigned as a whole to one of the preparations. In the first year, the vaccines were bivalent, containing types A (H3N2) and A (H1N1) components. In the second year, the vaccines also contained a type B component. In the first year, all viruses isolated were type A (H3N2); in the second, about three-quarters of the isolates were type B and the rest type A (H1N1). During both years, the vaccines protected the vaccinated children. Where significant differences existed, the live attenuated vaccine was more protective than the inactivated. Vaccination rates in schools in which live attenuated vaccines had been used were inversely related to illness rates of staff and unvaccinated children, suggesting that viral transmission had been reduced by the vaccine.

Adolescent↗
PubMed1993

Influenza A virus haemagglutinin polymorphism: pleiotropic antigenic variants of A/Shanghai/11/87 (H3N2) virus selected as high yield reassortants.

Genetic reassortment of the A/Shanghai/11/87 (H3N2) variant of influenza A virus with A/PR8/34 (H1N1) virus [the standard donor of high yield (hy) genes for influenza vaccine viruses] resulted in the isolation of two reassortants with differing H3 haemagglutinin (HA) phenotypes, X-99 and X-99a. The two HA phenotypes were derived from individual subpopulations of the H3N2 wild-type virus during the reassortment event. The HA mutants and their respectively derived reassortants (identical in RNA genotype) differed in antigenicity, replication characteristics, yield in chick embryos and haemagglutinin gene sequence. Despite antigenic differences in reactions to polyclonal rabbit antisera of 60%, both X-99 and X-99a, the hy reassortants, were equally immunogenic and protective in BALB/c mice to challenge by parental wild-type virus. Differences in HA phenotype were related to a Ser to Ile change at amino acid position 186. These findings emphasize the polymorphism of influenza virus strains as well as the need for caution in selection of vaccine strains from among antigenically distinct viral subpopulations.

Amino Acid Sequence↗
PubMed1993

Human papillomavirus DNA in glandular lesions of the uterine cervix.

AIMS: To assess the role of human papillomavirus in the pathogenesis of adenocarcinoma in situ, endocervical glandular dysplasia (a presumed precursor of adenocarcinoma) and endocervical glandular epithelial giant cell change. METHODS: Viral detection was carried out using an in situ hybridisation technique on paraffin wax sections. Biotinylated probes for human papillomavirus types 6/11, 16/18, 31/33/35 were used with a colorimetric detection system. RESULTS: Nine out of 21 (43%) cases of adenocarcinoma in situ contained human papillomavirus types 16/18, one of which was also positive for 31/33/35. Ten cases of glandular dysplasia and four cases of glandular epithelial multinucleation did not react with the probes used. CONCLUSIONS: These results indicate that while adenocarcinoma in situ is strongly associated with human papillomavirus infection, endocervical glandular dysplasia and glandular epithelial multinucleation are probably not associated with the virus.

Adenocarcinoma↗
PubMed1992

Importance sampling. I. Computing multimodel p values in linkage analysis.

In linkage analysis, when the lod score is maximized over multiple genetic models, standard asymptotic approximation of the significance level does not apply. Monte Carlo methods can be used to estimate the p value, but procedures currently used are extremely inefficient. We propose a Monte Carlo procedure based on the concept of importance sampling, which can be thousands of times more efficient than current procedures. With a reasonable amount of computing time, extremely accurate estimates of the p values can be obtained. Both theoretical results and an example of maturity-onset diabetes of the young (MODY) are presented to illustrate the efficiency performance of our method. Relations between single-model and multimodel p values are explored. The new procedure is also used to investigate the performance of asymptotic approximations in a single model situation.

Diabetes Mellitus, Type 2↗
PubMed1991

Comparative study of intra-articular pressure dynamics in joints with acute traumatic and chronic inflammatory effusions: potential implications for hypoxic-reperfusion injury.

It has been proposed that the process of hypoxic-reperfusion injury contributes to the persistence of synovitis in the inflamed human joint. The generation of pathological, exercise induced, intra-articular pressure leading to occlusion of the synovial microcirculation is central to this mechanism. However, acute traumatic inflammatory joint effusions rarely result in chronic synovitis, suggesting that either the basic hypothesis is incorrect, or that joints with acute traumatic effusions show different intra-articular pressure dynamics. In this study the intra-articular pressure was measured at rest and during isometric exercise in five patients with acute traumatic joint effusions and in nine patients with chronic inflammatory joint effusions. The generation of intra-articular pressure in the patients with acute traumatic effusions was significantly lower at rest (mean 2.0 v 19.6 mm Hg) and during exercise (mean 13.7 v 222.5 mm Hg) than in the patients with chronic effusions. This was due to reflex muscular inhibition around the joint, which inhibited the pathological generation of intra-articular pressure. This difference in the ability to generate intra-articular pressure might mitigate against hypoxic-reperfusion injury in joints with acute traumatic effusions, thereby explaining the paradoxical clinical observation that patients with acute traumatic inflammatory joint effusions rarely develop chronic synovitis.

Acute Disease↗
PubMed1991

Genetic factors in autoimmune thyroid disease analyzed by restriction fragment length polymorphisms of candidate genes.

Possible genetic effects on the development of autoimmune thyroid disease were studied by analysis of restriction fragment length polymorphisms (RFLPs) of candidate genes. Peripheral blood leukocyte DNA was obtained from 65 caucasian patients with Graves' disease, 63 caucasian patients with Hashimoto's thyroiditis, and 65 caucasian controls. RFLP analysis was carried out on genomic DNA, using probes for DR beta, DQ alpha, DQ beta, DP alpha, DP beta, T-cell receptor TCR alpha, and thyroid peroxidase. The methodology allowed HLA-DR and DQ typing and provided information on specific RFLP patterns related to T cell receptor (TCR)alpha, DP alpha and -beta, and -beta, and thyroid peroxidase. HLA-DR3 frequency was significantly increased in patients with Graves' disease, as reported previously by others, but neither DNA-derived subtype of DR3 was differentially increased. HLA-DQw2 was also present in increased frequency because of its linkage disequilibrium with HLA-DR3. It is uncertain whether the primary susceptibility is with DQ, DR, or another nearby locus. Susceptibility was not related in these studies to genetic loci recognized in these studies involving DQ alpha, DP, TCR, or thyroid peroxidase. A significant linkage disequilibrium between DR3 and a specific DX alpha RFLP was observed in Graves' disease, but is believed to be representative of a generalized linkage disequilibrium between DR3 and DX alpha, rather than a specific abnormality in Graves' disease. Previous studies indicating association with specific TCR RFLPs could not be reproduced. The relative risk for carriers of HLA-DR3 subtype A in this study was 7.37-fold. RFLP analysis offers the possibility of investigating linkage in a variety of candidate genes as well as established genetic relationships for potentially important subtypes. While the significant relationship with HLA-DR3/DQw2 was reconfirmed, the involvement of other genes or haplotypes could not be established.

DNA↗
PubMed1990

Characterization of an rRNA gene-specific cDNA probe: applications in bacterial identification.

Discontinuous DNA complementary to Escherichia coli 16S + 23S ribosomal RNA was synthesized by random oligonucleotide priming using reverse transcriptase. cDNA generated from native or denatured rRNA template was labelled by incorporation of either [alpha-32P]dCTP or digoxigenin-labelled dUTP during synthesis, followed by template hydrolysis. The specific activity of the radiolabelled cDNA was 10(7)-10(8) c.p.m. (micrograms rRNA template)-1 with 60-92% incorporation after 5 h. The length of the reverse transcript was between 20 and 1140 nucleotides and was unaffected by exclusion of primer. The cDNA probe could detect 3 pg rRNA by quantitative slot blot. In the non-radiolabelling digoxigenin system 3 micrograms template gave 0.5-2.0 micrograms cDNA after 24 h with a length of between 100 and 1225 bases. This probe could detect 50 pg rRNA. Probes were evaluated in the comparison of Pasteurella haemolytica biotypes by hybridization to Southern blots of restriction-endonuclease-digested total DNA. The digoxigenin-labelled probe was used to identify clinical isolates of Campylobacter jejuni to demonstrate its potential use in laboratories requiring high-sensitivity detection without the use of radioisotopes.

Alkaline Phosphatase↗