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Biomedical subjects

R Hopkins

Publications and source records attributed to R Hopkins.

At least 19 recordsLinked to original sources
PubMed2006

Functional variants of antioxidant genes in smokers with COPD and in those with normal lung function.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is predominantly the consequence of chronic smoking exposure, but its development may be influenced by genetic variants that affect lung remodelling, inflammation, and defence from oxidant stress. A study was undertaken to determine whether genetic variants within genes encoding the antioxidant enzymes superoxide dismutase (SOD) and catalase may be associated with the development of impaired lung function. METHODS: In a case-control study, the allele and genotype frequencies of functional polymorphisms from SOD1 (CuZnSOD), SOD2 (MnSOD), SOD3 (extracellular SOD), and catalase (CAT) were compared in chronic smokers with normal lung function (resistant smokers) and in those with COPD. RESULTS: Significantly higher frequencies of the G allele and CG/GG genotype of the 213 SOD3 polymorphism were found in resistant smokers (odds ratios (ORs) 4.3 (95% CI 1.5 to 13.3) and 4.2, 95% CI 1.4 to 13.3), Bonferroni corrected p = 0.02 and p = 0.02, respectively) than in those with COPD. There were no differences between the COPD and resistant smokers for the SOD1, SOD2, or CAT polymorphisms tested. CONCLUSIONS: The 213Gly variant of the SOD3 gene may, through antioxidant or anti-inflammatory effects, confer a degree of resistance in some smokers to the development of COPD.

Adult↗
PubMed2006

Posttransplant lymphoproliferative disorder: a pictorial review.

Posttransplant lymphoproliferative disorder (PTLD) is a serious and potentially fatal complication after solid organ and haemopoietic stem cell transplantation. The frequency of PTLD varies with the type of organ transplant but overall it affects 2-10% of all solid organ transplant recipients. Most cases develop within 1 year after the transplant, although occasional cases present 5-10 years later. Posttransplant lymphoproliferative disorder is clinically and pathologically heterogeneous - the majority are of the non-Hodgkin's lymphoma type, whereas Hodgkin's lymphoma arising after transplantation is rare. We have retrospectively reviewed patients with a histological diagnosis of PTLD after a solid organ transplant. We present the imaging features and a clinical review of this condition. Early diagnosis of PTLD may alter the management and outcome of the disease. The radiologist can play a vital role in establishing the diagnosis by imaging features supplemented with percutaneous biopsy and also in monitoring the disease response to treatment.

Humans↗
PubMed2005

Determinants of plasma D-dimer levels in a traveling population.

BACKGROUND: Plasma D-dimer measurement is a widely used diagnostic test for assessing individuals with suspected venous thromboembolism (VTE). Whilst a negative test is helpful in ruling out thrombosis, the significance and determinants of an elevated plasma D-dimer level in otherwise healthy subjects are poorly understood. OBJECTIVES: To determine the association between recognized risk factors for VTE and plasma D-dimer levels in an adult population. SUBJECTS AND METHODS: Blood samples for measurement of plasma D-dimer levels were obtained from 1000 adults aged <70 years who were participating in a study investigating the incidence of VTE in long distance air travellers. The relationship between D-dimer levels and selected risks factors for VTE including thrombophilia status was investigated. RESULTS: The median (Inter-quartile range) D-dimer level was 243 ng mL(-1) (175-345). Multivariate analysis showed that plasma D-dimer levels were positively associated with increasing age, larger body mass index, female gender, the use of hormone therapy, thrombophilia state, and the presence of co-morbid conditions. CONCLUSION: Plasma D-dimer levels vary markedly between individuals and are associated with known risk factors for VTE, including the presence of thrombophilia conditions. The potential role for the measurement of plasma D-dimer as a marker for thrombosis risk requires further investigation.

Age Factors↗
PubMed2004

Transforming growth factor-beta1 genotype and susceptibility to chronic obstructive pulmonary disease.

BACKGROUND: Only a few long term smokers develop symptomatic chronic obstructive pulmonary disease (COPD) and this may be due, at least in part, to genetic susceptibility to the disease. Transforming growth factor beta1 (TGF-beta1) has a number of actions that make it a candidate for a role in the pathogenesis of COPD. We have investigated a single nucleotide polymorphism at exon 1 nucleotide position 29 (T-->C) of the TGF-beta1 gene that produces a substitution at codon 10 (Leu-->Pro). METHODS: The frequency of this polymorphism was determined in 165 subjects with COPD, 140 healthy blood donors, and 76 smokers with normal lung function (resistant smokers) using the polymerase chain reaction and restriction enzyme fragment length polymorphism. RESULTS: The distribution of genotypes was Leu-Leu (41.8%), Leu-Pro (50.3%), and Pro-Pro (7.9%) for subjects with COPD, which was significantly different from the control subjects (blood donors: Leu-Leu (29.3%), Leu-Pro (52.1%) and Pro-Pro (18.6%), p=0.006; resistant smokers: Leu-Leu (28.9%), Leu-Pro (51.3%) and Pro-Pro (19.7%), p=0.02). The Pro10 allele was less common in subjects with COPD (33%) than in blood donors (45%; OR=0.62, 95% CI 0.45 to 0.86, p=0.005) and resistant smokers (45%; OR=0.59, 95% CI 0.40 to 0.88, p=0.01). CONCLUSIONS: The proline allele at codon 10 of the TGF-beta1 gene occurs more commonly in control subjects than in individuals with COPD. This allele is associated with increased production of TGF-beta1 which raises the possibility that TGF-beta1 has a protective role in COPD.

Adult↗
PubMed2003

The complete nucleotide sequence of Subterranean clover mottle virus.

The complete nucleotide sequence of Subterranean clover mottle virus (SCMoV) genomic RNA has been determined. The SCMoV genome is 4,258 nucleotides in length. It shares most nucleotide and amino acid sequence identity with the genome of Lucerne transient streak virus (LTSV). SCMoV RNA encodes four overlapping open reading frames and has a genome organisation similar to that of Cocksfoot mottle virus (CfMV). ORF1 and ORF4 are predicted to encode single proteins. ORF2 is predicted to encode two proteins that are derived from a -1 translational frameshift between two overlapping reading frames (ORF2a and ORF2b). A search of amino acid databases did not find a significant match for ORF1 and the function of this protein remains unclear. ORF2a contains a motif typical of chymotrypsin-like serine proteases and ORF2b has motifs characteristically present in positive-stranded RNA-dependent RNA polymerases. ORF4 is likely to be expressed from a subgenomic RNA and encodes the viral coat protein. The ORF2a/ORF2b overlapping gene expression strategy used by SCMoV and CfMV is similar to that of the poleroviruses and differ from that of other published sobemoviruses. These results suggest that the sobemoviruses could now be divided into two distinct subgroups based on those that express the RNA-dependent RNA polymerase from a single, in-frame polyprotein, and those that express it via a -1 translational frameshifting mechanism.

Amino Acid Sequence↗
PubMed2002

The abdominal radiograph: a pictorial review.

The plain abdominal radiograph is one of the most frequently requested X-ray examinations by junior surgical and accident and emergency staff. Interpretation is often difficult, but this review outlines normal appearances, suggests a strategy for evaluation, and covers the common pathological appearances seen in hospital practice.

Aortic Aneurysm, Abdominal↗
PubMed2001

Monitoring end-tidal carbon dioxide during weaning from cardiopulmonary bypass in patients without significant lung disease.

End-tidal carbon dioxide tension (PETCO(2)) changes with fluctuations in cardiac output (CO). We compared PETCO(2) to pulmonary artery blood flow (PAQt) during weaning from cardiopulmonary bypass (CPB) in normothermic patients without significant pulmonary disease. Fifteen consecutive adult cardiac surgical patients were prospectively studied during and shortly after weaning from CPB. Before separation from CPB, PETCO(2) and PAQt were measured, the latter by transesophageal Doppler echocardiography. At the time of measurements patients were normothermic, and ventilated at 6 breaths/min with tidal volumes of 10 mL/kg. After separation from CPB, thermodilution cardiac output (TDCO) was measured in addition to PAQt and PETCO(2). Regression and bias analyses were used to compare PETCO(2), PAQt, and TDCO. Seventy measurements were recorded; 31 before separation from CPB and 39 after separation from CPB. A good correlation was seen between PAQt and PETCO(2) (r = 0.88) and between TDCO and PAQt (r = 0.93; mean bias 0.03 L/min; SD 0.52 L/min). The regression analysis of PAQt on PETCO(2) showed greater variability at PETCO(2) levels > 34 mm Hg (n = 22; r = 0.14). Increases in PETCO(2) plateaued at this level, although PAQt continued to increase. When PETCO(2) was more than 30 mm Hg, all PAQt and TDCO values were >4.0 L/min (>2.0 L/min/m(2)). When PETCO(2) exceeded 34 mm Hg, all values of PAQt, and 28/29 values of TDCO were more than 5 L/min (>2.5 L/min/m(2)). One patient had TDCO of 4.69 L/min (2.39 L/min/m(2)). In normothermic patients without significant pulmonary disease, PETCO(2) is a useful index of PAQt during separation from CPB. Under the clinical settings in this study, a PETCO(2) greater than 30 mm Hg was invariably associated with a CO more than 4.0 L/min or a cardiac index >2.0 L/min/m(2).

Aged↗
PubMed2001

Calcification on the chest X-ray: a pictorial review.

There are numerous causes of calcification on the chest radiograph. Their striking appearance can lead to anxiety among junior medical staff. This article aims to categorize these appearances, and to give examples of the most common causes seen.

Calcinosis↗
PubMed2000

Riverine inputs of major ions and trace elements to the tidal reaches of the River Tweed, UK.

This paper examines spatial and temporal variability in freshwater inputs of trace elements and major ions to the tidal reaches of the River Tweed. The relationships between concentrations of major ions and trace elements (in dissolved and acid-available particulate forms) and flow are examined, and a simple two-component endmember mixing analysis performed to link river water chemistry to catchment sources, and to identify whether within-river processes modify concentrations to produce non-conservative behaviour. The results indicate that most dissolved major ions and trace elements behave conservatively in the lower reaches of the River Tweed, the variability in concentrations being dominated by hydrology and the existence of different high-flow and low-flow endmember runoff chemistries. This suggests that the variability in concentration of most dissolved trace elements and major ions in the lower Tweed can be modelled using simple mixing relationships. However, the relationships between pH, Ca, Mg and Gran alkalinity show pronounced non-conservative behaviour, indicating the importance of understanding within-river process for modelling these determinants. The non-conservative behaviour identified is related to biological controls and the resultant diurnal variations in pH which promote daytime removal of Ca from solution by precipitation of calcium carbonate (and corresponding removal of Mg by co-precipitation) during extreme low-flow conditions and algal blooms during the summer.

Eutrophication↗
PubMed2000

Epidemiological features of and public health response to a St. Louis encephalitis epidemic in Florida, 1990-1.

A St. Louis encephalitis (SLE) epidemic in Florida during 25 weeks in 1990-1, resulted in 222 laboratory-diagnosed cases, an attack rate in the 28 affected counties of 2.25/100,000. Disease risk rose with advanced age, to 17.14/100,000 in persons over 80 years, and all 14 fatal cases were in persons over 55 years (median, 70 years). Community serosurveys in Indian River County, the epicenter of the outbreak (attack rate 21/100,000), showed acute asymptomatic infections in 3.6% of the persons surveyed, with higher rates in persons with outdoor occupational exposure (7.4%) and in clients of a shelter for the indigent (13.3%). A matched case-control study found that evening outdoor exposure for more than 2 h was associated with an increased risk for acquiring illness (odds ratio [OR] 4.33, 95% CI 1.23-15.21) while a number of recommended personal protective measures were protective. Four SLE patients were dually infected with Highlands J virus, the first reported cases of acute infection with this alphavirus. The case-control study provided the first evidence that a public education campaign to reduce exposure had a protective effect against acquiring the disease.

Adolescent↗
PubMed2000

Carboxyhemoglobin half-life in carbon monoxide-poisoned patients treated with 100% oxygen at atmospheric pressure.

STUDY OBJECTIVES: There are large reported differences for the carboxyhemoglobin (COHb) half-life (COHb t(1/2)) in humans breathing 100% atmospheric O(2) following CO inhalation in tightly controlled experiments compared to the COHb t(1/2) observed in clinical CO poisoning (range, 36 to 131 min, respectively). Other reports have suggested that the COHb t(1/2) may be affected by gender differences, age, and lung function. We wished to test the hypothesis that the COHb t(1/2) might also be influenced by CO poisoning vs experimental CO exposure, by a history of loss of consciousness (LOC), concurrent tobacco smoking, and by PaO(2). The purpose of the present study was to measure the COHb t(1/2) in a cohort of CO-poisoned patients and to determine if those listed factors influenced the COHb t(1/2). DESIGN: Retrospective chart review from 1985 to 1995. We calculated the COHb t(1/2) of CO-poisoned patients who were treated with high-flow supplemental atmospheric pressure O(2) delivered by nonrebreather face mask or endotracheal tube. SETTING: Hyperbaric medicine department of a tertiary-care teaching hospital. PATIENTS: Of 240 CO-poisoned patients, 93 had at least two COHb measurements > 2% (upper limit of normal) with recorded times of the measurements, permitting calculation of the COHb t(1/2). RESULTS: The COHb t(1/2) was 74 +/- 25 min (mean +/- 1 SD) with a range from 26 to 148 min. By stepwise multiple linear regression analysis, the PaO(2) influenced the COHb t(1/2) (R(2) = 0.19; p < 0.001), whereas the COHb t(1/2) was not influenced by gender, age, smoke inhalation, history of LOC, concurrent tobacco smoking, degree of initial metabolic acidosis (base excess), or initial COHb level. CONCLUSIONS: The COHb t(1/2) of 93 CO-poisoned patients treated with 100% O(2) at atmospheric pressure was 74 +/- 25 min, considerably shorter than the COHb t(1/2) reported in prior clinical reports (approximately 130 +/- 130 min) and was influenced only by the patient's PaO(2).

Adolescent↗
PubMed1999

A pilot study evaluating the effectiveness of individual inpatient cognitive-behavioural therapy in early psychosis.

BACKGROUND: Recent research indicates that cognitive-behaviour therapy (CBT) can be effective in ameliorating persistent positive symptoms in chronic psychotic patients. The effectiveness of CBT in acute and recent-onset psychosis has been little explored, although a recent pilot study indicated that CBT could significantly improve recovery in acutely psychotic inpatients. METHOD: Short-term individual CBT was compared to supportive counselling/psychoeducation (SC) as an adjunct to standard inpatient hospital care and medication in 21 inpatients experiencing a recent-onset acute schizophrenic episode. RESULTS: Both groups showed significant reductions in Brief Psychiatric Rating Scale (BPRS) scores following treatment, although there were no group differences. Time to discharge did not differ significantly between the groups, although there was a greater variance for the SC patients. Two-year follow-up showed no significant differences between the groups, although the number of patients who relapsed, the number of relapses and the time to recurrence of psychotic symptoms was lower in the CBT group than the SC group. Interestingly, the time to readmission was shorter in the CBT group. CONCLUSIONS: CBT and SC are acceptable treatments for recent-onset acutely psychotic inpatients. A larger randomised controlled trial over multiple hospital sites is warranted.

Acute Disease↗