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Biomedical subjects

J R Thompson

Publications and source records attributed to J R Thompson.

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

Mapping of genetic loci predisposing to hypertriglyceridaemia in the hereditary hypertriglyceridaemic rat: analysis of genetic association with related traits of the insulin resistance syndrome.

AIMS/HYPOTHESIS: Hypertriglyceridaemia is an important risk factor for coronary heart disease, especially in the context of the insulin resistance syndrome where it often occurs with hypertension. The two phenotypes are also associated in the hereditary hypertriglyceridaemic (hHTg) rat. The aim of this study was to map quantitative trait loci that affect plasma triglyceride concentration in the hHTg rat and determine whether they co-localize with loci for blood pressure. METHODS: Second filial generation progeny (n=189) from a cross of the hHTg rat with the Brown Norway rat were phenotyped for fasting plasma triglyceride, glucose and insulin concentrations, and direct unrestrained resting blood pressure. A partial genome-scan was conducted using 153 microsatellite markers that were polymorphic between the two strains. RESULTS: A major locus (lod score 6.5) influencing plasma triglyceride concentration in a co-dominant fashion was mapped to chromosome 4 between D1Mit 5 and D1Mit17. Chromosome 8 contained multiple peaks with a lod score greater than 4.0 influencing triglyceride concentration. Importantly, none of the triglyceride loci had an effect on blood pressure. The triglyceride locus on chromosome 4 co-localized with a locus for fasting plasma insulin (lod score 4.1), although the effect on insulin concentration was in the opposite direction to that on triglyceride. CONCLUSION/INTERPRETATION: We have mapped the major loci that affect plasma triglyceride concentration in the hHTg rat. These loci do not influence blood pressure suggesting that these commonly associated phenotypes of the insulin resistance syndrome are not be due to pleiotropic effects of the same gene(s).

Animals↗
PubMed2003

Multiplex RT-PCR detection of four aphid-borne strawberry viruses in Fragaria spp. in combination with a plant mRNA specific internal control.

The principal aphid-borne viruses infecting Strawberry (Fragaria spp.) Strawberry crinkle virus (SCV), Strawberry mild yellow edge virus (SMYEV), Strawberry mottle virus (SMoV) and Strawberry vein banding virus (SVBV) can cause serious crop losses. In this paper, a multiplex reverse transcriptase polymerase chain reaction (RT-PCR) method is described for the simultaneous detection of all four viruses in combination with a plant mRNA specific internal control which can be used as an indicator of the effectiveness of the extraction and RT-PCR. In total, 18 strawberry isolates infected naturally were analysed by this method. Every combination of RNA virus was able to be detected and a full complement of all four viruses were found together in three isolates, all taken from wild strawberry (Fragaria chiloensis (L.) Duch.) in Chile. The upper detection limit for the four viruses was at an extract dilution of 1/200. The broad applicability of the RNA specific internal control primers-which produced a PCR fragment of the expected size in 25 of 27 plant species tested-combined with improvements, made in extraction methods described provides potentially a standard method for comparable RT-PCR analyses in a wide variety of plant species.

Animals↗
PubMed2003

Overnight deep body temperature and urinary cortisol excretion in infants from economically deprived areas.

OBJECTIVES: To assess the pattern of postnatal physiological maturation in economically deprived infants by measuring the age-related changes in deep body temperature during night-time sleep. SETTING: Inner city Leicester, UK. PARTICIPANTS: Forty-eight infants aged 6-21 weeks from economically deprived areas and 87 control infants from more affluent areas. OUTCOME MEASURES: Average deep body temperature between 2 and 4 h after bedtime, overnight and early morning urinary cortisol excretion. RESULTS: Both groups showed a decline in overnight deep body temperature with age that averaged 0.030 degrees C per week (SE = 0.003). Over the age range studied, the average age-adjusted overnight temperature in the infants from deprived homes was 0.090 degrees C (SE = 0.028) higher than that for the affluent group (P = 0.001). Deprived infants had on average 51% higher overnight urinary cortisol and 80% higher morning cortisol. The differences remained when the effects of room temperature, clothing, smoking, birthweight and gestational age were taken into account. CONCLUSION: These indicators of postnatal physiological maturation suggest that infants from economically deprived homes mature less quickly. This might increase their vulnerability to illness.

Age Factors↗
PubMed2003

Signs and symptoms of illness in early infancy: associations with sudden infant death.

AIMS: to describe a pattern of illness in "normal" infants, and to assess to what extent this may differ in infants who die suddenly and unexpectedly. METHODS: All infants are on the CONI (Care of the Next Infant) scheme in which mothers record symptoms and signs of illness prospectively, on a daily basis from birth to approximately age 6 months. The symptoms of infants who die suddenly and unexpectedly are compared with those of a consecutive sample of infants who survive. Twenty one babies died suddenly, of whom 11 were cot deaths and 10 had "known causes" of death. Ninety eight infants who survived were used as consecutive controls. Prospective daily records of the presence or absence of 26 signs and symptoms were kept by all of the mothers, commencing at birth and lasting an average of 176 days in survivors; 84 days in SIDS; and 93 days in infants who died of known causes. RESULTS: Standardised for age and the time of year, on any given day, the mothers of the SIDS infants were over eight times more likely to record their child as being pale, six times more likely to be sweating, and twice as likely to be irritable. Other signs and symptoms which were three times more likely to be recorded were sore gums, dry stools, and coldness. Infants who died of known causes generally had fewer symptoms. CONCLUSIONS: Cot death infants have a range of symptoms which appear to be of a general nature, and not related to any one system. Symptoms are seen throughout life and not related to the time of death.

Apnea↗
PubMed2003

Differences in the management of amblyopia between European countries.

BACKGROUND: Amblyopia treatment is not standardised and differences between centres and countries have not been systematically investigated. This survey compares the different patterns of orthoptic treatment of amblyopia in the United Kingdom (UK) and three German speaking countries (GSC). METHODS: Questionnaires were sent to orthoptists in the UK and the GSC asking for their preferred choices of treatment of amblyopia between the ages of 6 months to 10 years. RESULTS: The following significant differences in management of amblyopia were found: (1) the number of hours of occlusion per week was higher in the GSC, p<0.0001, (2) orthoptists in the GSC treat amblyopia up to an older age. Orthoptists in the GSC and in the UK predicted similar treatment outcomes. CONCLUSION: Orthoptists in the GSC usually treat patients more intensively and for longer, while the prediction of visual outcome does not differ significantly between countries. These results highlight the lack of standardisation in the treatment of the various types of amblyopia.

Age Factors↗
PubMed2002

A study of heredity as a risk factor in strabismus.

AIMS: Inheritance is recognised to have a part in the aetiology of strabismus but previous studies have not adequately distinguished between different types of strabismus leading to wide variations in reported findings. The aim of this study was to investigate the importance of heredity in different types of strabismus. METHODS: The parents of children attending for treatment of strabismus over a one-month period were interviewed to identify relatives with a history of strabismus. A complete three-generation pedigree was established for 96 index cases who were classified into four groups: infantile esotropia (26 cases), accommodative esotropia (49 cases), anisometropic esotropia (15 cases), and exotropia (six cases). RESULTS: Forty-three of a total of 165 (26.1%) first degree relatives of patients with hypermetropic accommodative esotropia were affected. In contrast, 15 of a total of 101 (14.9%) first degree relatives of patients with infantile esotropia, eight of a total of 66 (12.1%) first degree relatives of patients with anisometropic esotropia, and one of a total of 25 (4%) first degree relatives of patients with exotropia were affected. Analysing the data using logistic regression with a random term for family showed a significantly higher proportion of affected first degree relatives in the accommodative group than in any of the other three diagnostic groups. CONCLUSION: A history of strabismus appears to be more common in hypermetropic accommodative esotropia than in infantile esotropia, anisometropic esotropia or exotropia. More detailed investigation of the role of heredity in the aetiology of accommodative esotropia is needed.

Child↗
PubMed2002

The National Survey of Trabeculectomy. III. Early and late complications.

PURPOSE: There is a considerable body of literature relating to trabeculectomy, however there are no data representative of the national experience of trabeculectomy in the United Kingdom (UK). The Department of Health funded a national survey of trabeculectomy to establish current practice patterns and the outcome of trabeculectomy in the National Health Service (NHS). In this paper we present the reported complications of first-time trabeculectomy from a nationally representative cohort of patients with chronic open angle glaucoma. METHODS: Cross-sectional study of consultant ophthalmologists performing trabeculectomy in the NHS. Participants recruited their four most recent consecutive first-time trabeculectomy cases with chronic open angle glaucoma according to study eligibility criteria and data were collected by self-administered questionnaire. FOLLOW-UP: one year post-trabeculectomy. MAIN OUTCOME MEASURES: occurrence of early and late complications. RESULTS: Clinical outcome data were available for 1240 (85.3%) of cases. Early complications were reported in 578 (46.6%) cases and late complications in 512 (42.3%) cases. Some cases had more than one complication. The most frequent early complications were hyphaema (n = 304, 24.6%), shallow anterior chamber (n = 296, 23.9%), hypotony (n = 296, 24.3%), wound leak (n = 216, 17.8%) and choroidal detachment (n = 175, 14.1%). The most frequent late complications were cataract (n = 251, 20.2%), visual loss (n = 230, 18.8%) and encapsulated bleb (n = 42, 3.4%). The occurrence of most complications was not associated with a consultant's specialist interest, level of activity, type of hospital or region. Encapsulated bleb was reported more frequently in a university hospital setting. CONCLUSIONS: The complication rates reported in this paper represent the national experience of first-time trabeculectomy for open angle glaucoma in the UK. These are similar to previous published studies and highlight in particular, the impact of trabeculectomy on visual acuity in the first year following surgery. This survey provides valid and clinically relevant data on the complications of trabeculectomy for the production of guidelines and standards for audit at regional, local and individual level.

Anterior Chamber↗
PubMed2002

National audit of the outcome of primary surgery for rhegmatogenous retinal detachment. I. Sample and methods.

PURPOSE: This national study was designed to audit anatomical outcome and complications relating to primary surgery for rhegmatogenous retinal detachments. This paper presents survey methods, characteristics of participating consultants and the demographic and clinical characteristics of the patient sample. METHODS: Two surveys were undertaken. The first identified consultants who at the time performed retinal detachment surgery in the National Health Service. These surgeons formed the sampling frame for a nationwide cross-sectional clinical study that audited the outcomes of primary surgery for rhegmatogenous retinal detachments. Consultants selected patients according to the study eligibility criteria and data were collected by self-administered postal questionnaires. A validation exercise was carried out to examine selection bias and reporting accuracy. RESULTS: Only 256/671 (38%) of UK consultants, who responded to the first survey, indicated that they performed retinal detachment surgery on NHS patients. Annual activity varied between 0 and 400 primary procedures for rhegmatogenous retinal detachments. Seven hundred and sixty-eight eligible patients from 167 consultants were recruited for the clinical study. Twenty per cent of patients had a single retinal break with less than one quadrant of associated detachment and 45% had single or multiple breaks within the same quadrant and/or less than two quadrants of associated retinal detachment. Over 50% patients had single or multiple horseshoe tears. Validation studies suggested that there was no significant bias from the selection of patients or inaccuracy in reporting outcomes. CONCLUSIONS: This large unselected group of primary rhegmatogenous retinal detachments provides a representative sample for considering variations in re-attachment rates.

Adolescent↗
PubMed2002

National audit of the outcome of primary surgery for rhegmatogenous retinal detachment. II. Clinical outcomes.

PURPOSE: This national study was designed to audit anatomical outcome and complications relating to primary surgery for rhegmatogenous retinal detachments. This paper presents success and complication rates, and examines variations in outcome. METHODS: Sampling and recruitment details of this nationwide cross-sectional survey of 768 patients of 167 consultant ophthalmologists having their first operation for rhegmatogenous retinal detachment have been described. The main clinical outcomes detailed here are anatomical reattachment at 3 months after surgery and complications related to surgery. Consultants with a declared special interest in retinal surgery and able to perform pars plana vitrectomy were designated specialists for the analyses. RESULTS: Overall reattachment rate with a single procedure was 77% (95% CI 73.9-80.2). There were significant differences in reattachment rates between specialists and non-specialists. Without allowing for case-mix, specialists had a reattachment rate of 82% (95% CI 77.9-85.7) with a single procedure and non-specialists 71% (95% CI 65.9-76.0). Allowing for case-mix, there was a significant difference between specialists and non-specialists for grade 2 detachments of 87% and 70% respectively (P < 0.0001). Analysing detachments by break type, the largest difference between specialists and non-specialists was observed for retinal detachments secondary to horseshoe tears, 80% and 68% respectively (P < 0.003). Specialists met the standards set for primary reattachment rates, while non-specialists did not. Over a third of patients had at least one complication reported at some point during the audit period. CONCLUSIONS: Significant differences were seen in reattachment rates between specialists and non-specialists, overall and for specific subgroups of patients. This study provides relevant, robust and valid standards to enable all surgeons to audit their own surgical outcomes for primary retinal detachment repair in rhegmatogenous retinal detachments, identify common categories of failure and aim to improve results.

Adolescent↗
PubMed2002

Characterization and complete nucleotide sequence of Strawberry mottle virus: a tentative member of a new family of bipartite plant picorna-like viruses.

An isolate of Strawberry mottle virus (SMoV) was transferred from Fragaria vesca to Nicotiana occidentalis and Chenopodium quinoa by mechanical inoculation. Electron micrographs of infected tissues showed the presence of isometric particles of approximately 28 nm in diameter. SMoV-associated tubular structures were also conspicuous, particularly in the plasmodesmata of C. quinoa. DsRNA extraction of SMoV-infected N. occidentalis yielded two bands of 6.3 and 7.8 kbp which were cloned and sequenced. Gaps in the sequence, including the 5' and 3' ends, were filled using RT-PCR and RACE. The genome of SMoV was found to consist of RNA1 and RNA2 of 7036 and 5619 nt, respectively, excluding a poly(A) tail. Each RNA encodes one polyprotein and has a 3' non-coding region of approximately 1150 nt. The polyprotein of RNA1 contains regions with identities to helicase, viral genome-linked protein, protease and polymerase (RdRp), and shares its closest similarity with RNA1 of the tentative nepovirus Satsuma dwarf virus (SDV). The polyprotein of RNA2 displayed some similarity to the large coat protein domain of SDV and related viruses. Phylogenetic analysis of the RdRp region showed that SMoV falls into a separate group containing SDV, Apple latent spherical virus, Naval orange infectious mottling virus and Rice tungro spherical virus. Given the size of RNA2 and the presence of a long 3' non-coding region, SMoV is more typical of a nepovirus, although atypically for a nepovirus it is aphid transmissible. We propose that SMoV is a tentative member of an SDV-like lineage of picorna-like viruses.

3' Untranslated Regions↗
PubMed2001

Maternal folate supplementation in pregnancy and protection against acute lymphoblastic leukaemia in childhood: a case-control study.

BACKGROUND: Acute lymphoblastic leukaemia is the most common childhood cancer in more-developed countries but it has few recognised risk factors or preventive measures. We aimed to determine and assess the risk factors associated with this disease. METHODS: From 1984 to 1992, we investigated known and suspected risk factors for common acute lymphoblastic leukaemia diagnosed in a population-based case-control study of children aged 0-14 years in Western Australia. 83 children in the study group came from the sole referral centre for paediatric cancer in the state and 166 controls matched for age and sex were recruited through a postal survey of people randomly selected from the state electoral roll. We interviewed mothers of 83 study and 166 control children (82% and 74%, respectively, of those eligible). Fathers completed a self-administered questionnaire. FINDINGS: We recorded a protective association between iron or folate supplementation in pregnancy and risk of common acute lymphoblastic leukaemia in the child (odds ratio 0.37 [95% CI 0.21-0.65]; p=0.001). For iron alone, the odds ratio was 0.75 (0.37-1.51); only one mother took folate without iron. Further analyses of folate use with or without iron (0.40; 0.21-0.73) showed that the protective effect varies little by time of first use of supplements or for how long they were taken. The association was not weakened by adjustment for potentially confounding variables. INTERPRETATION: Our results, though unexpected, suggest that folate supplementation in pregnancy reduces the risk of common acute lymphoblastic leukaemia in the child.

Adolescent↗
PubMed2001

Estimating equations for kappa statistics.

Kappa statistics are often used for measuring agreement or association. The original measure suggested by Cohen for use with nominal data has since been generalized in a number of ways, including the incorporation of weights, adaptation for use with more than one rater and the application to bivariate data. Each modification requires a new approximation to the standard error and these have usually been derived by the delta method. This paper illustrates the use of estimating equations for kappa which offer a unified approach to many previously considered situations and which is also applicable to more complex designs.

Algorithms↗
PubMed2001

Telomere shortening in atherosclerosis.

Eukaryotic chromosomes end with telomeres, which shorten with cellular ageing. We investigated whether atherosclerosis is associated with systemic evidence of accelerated cellular ageing. We compared mean length of terminal restriction fragments (TRF), a measure of average telomere size, in leucocyte DNA of ten patients with severe coronary artery disease (CAD) with that of 20 controls without CAD. Adjusting for age and sex, cases had mean TRF lengths of 303 (SD 90) base pairs shorter than those of controls (p=0.002)-ie, equivalent in size to individuals with no CAD who are 8.6 years older. Although this is a pilot study, the findings could be relevant to the pathogenesis of atherosclerosis.

Adult↗
PubMed2001

Structural analyses of a malate dehydrogenase with a variable active site.

Malate dehydrogenase specifically oxidizes malate to oxaloacetate. The specificity arises from three arginines in the active site pocket that coordinate the carboxyl groups of the substrate and stabilize the newly forming hydroxyl/keto group during catalysis. Here, the role of Arg-153 in distinguishing substrate specificity is examined by the mutant R153C. The x-ray structure of the NAD binary complex at 2.1 A reveals two sulfate ions bound in the closed form of the active site. The sulfate that occupies the substrate binding site has been translated approximately 2 A toward the opening of the active site cavity. Its new location suggests that the low catalytic turnover observed in the R153C mutant may be due to misalignment of the hydroxyl or ketone group of the substrate with the appropriate catalytic residues. In the NAD.pyruvate ternary complex, the monocarboxylic inhibitor is bound in the open conformation of the active site. The pyruvate is coordinated not by the active site arginines, but through weak hydrogen bonds to the amide backbone. Energy minimized molecular models of unnatural analogues of R153C (Wright, S. K., and Viola, R. E. (2001) J. Biol. Chem. 276, 31151-31155) reveal that the regenerated amino and amido side chains can form favorable hydrogen-bonding interactions with the substrate, although a return to native enzymatic activity is not observed. The low activity of the modified R153C enzymes suggests that precise positioning of the guanidino side chain is essential for optimal orientation of the substrate.

Binding Sites↗
PubMed2001

Hepatic carnitine palmitoyl transferase 1 (CPT1 A) deficiency in North American Hutterites (Canadian and American): evidence for a founder effect and results of a pilot study on a DNA-based newborn screening program.

We describe six patients with hepatic carnitine palmitoyl transferase (CPT1 A) deficiency who are members of a large extended Hutterite kindred living in widely scattered communities in the United States and Canadian Prairies. Two patients have significant neurological impairment due to severe recurrent hypoglycemic crises. The remaining four patients with earlier detection and treatment have near normal outcomes. The Canadian and American Hutterite families share two common ancestors who married in 1812, about 60 years before the Hutterites arrived in North America and prior to their subdivision into the three groups (Schmiedeleut, Dariusleut, and the Lehrerleut). These patients share a common haplotype on chromosome 11q13 and are all homozygous for a common CPT1 A G710E mutation, suggesting a founder effect. The clustering of such a rare disorder of fatty acid oxidation prompted us to initiate a pilot DNA-based neonatal screening program to determine the carrier frequency of this mutation in Hutterite newborns with the participation and support of the community. To date our carrier frequency is 1/16, close to the predicted frequency based on diagnosed patients and number of births. We believe our newborn screening program for CPT1 A deficiency in the Hutterite community will serve as a prototype model for delivery of targeted genetic services to other similar unique genetic isolates.

Adolescent↗
PubMed2001

Dynamic pelvic magnetic resonance imaging and cystocolpoproctography alter surgical management of pelvic floor disorders.

PURPOSE: Pelvic organ prolapse results in a spectrum of progressively disabling disorders. Despite attempts to standardize the clinical examination, a variety of imaging techniques are used. The purpose of this study was to evaluate dynamic pelvic magnetic resonance imaging and dynamic cystocolpoproctography in the surgical management of females with complex pelvic floor disorders. METHODS: Twenty-two patients were identified from The Johns Hopkins Pelvic Floor Disorders Center database who had symptoms of complex pelvic organ prolapse and underwent dynamic magnetic resonance, dynamic cystocolpoproctography, and subsequent multidisciplinary review and operative repair. RESULTS: The mean age of the study group was 58 +/- 13 years, and all patients were Caucasian. Constipation (95.5 percent), urinary incontinence (77.3 percent), complaints of incomplete fecal evacuation (59.1 percent), and bulging vaginal tissues (54.4 percent) were the most common complaints on presentation. All patients had multiple complaints with a median number of 4 symptoms (range, 2-8). Physical examination, dynamic magnetic resonance imaging, and dynamic cystocolpoproctography were concordant for rectocele, enterocele, cystocele, and perineal descent in only 41 percent of patients. Dynamic imaging lead to changes in the initial operative plan in 41 percent of patients. Dynamic magnetic resonance was the only modality that identified levator ani hernias. Dynamic cystocolpoproctography identified sigmoidoceles and internal rectal prolapse more often than physical examination or dynamic magnetic resonance. CONCLUSIONS: Levator ani hernias are often missed by physical examination and traditional fluoroscopic imaging. Dynamic magnetic resonance and cystocolpoproctography are complementary studies to the physical examination that may alter the surgical management of females with complex pelvic floor disorders.

Adult↗