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Biomedical subjects

S Mason

Publications and source records attributed to S Mason.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effect of population screening and treatment for Helicobacter pylori on dyspepsia and quality of life in the community: a randomised controlled trial. Leeds HELP Study Group.

BACKGROUND: Infection with Helicobacter pylori is the main cause of peptic-ulcer disease. Treatment of this infection might lower the prevalence of dyspepsia in the community and improve quality of life. We investigated this possibility in a double-blind randomised controlled trial. METHODS: Individuals aged 40-49 years were randomly selected from the lists of 36 primary-care centres. A researcher interviewed participants with a validated dyspepsia questionnaire and the psychological general wellbeing index (PGWB). H. pylori status was assessed by the carbon-13-labelled urea breath test. Infected participants were randomly assigned active treatment (omeprazole 20 mg, clarithromycin 250 mg, and tinidazole 500 mg, each twice daily for 7 days) or identical placebo. Participants were followed up at 6 months and 2 years. FINDINGS: Of 32,929 individuals invited, 8455 attended and were eligible; 2324 were positive for H. pylori and were assigned active treatment (1161) or placebo (1163). 1773 (76%) returned at 2 years. Dyspepsia or symptoms of gastro-oesophageal reflux were reported in 247 (28%) of 880 in the treatment group and 291 (33%) of 871 in the placebo group (absolute-risk reduction 5% [95% CI 1-10]). H. pylori treatment had no significant effect on quality of life (mean difference in PGWB score between groups 0.86 [-0.33 to 2.05]). INTERPRETATION: Community screening and treatment for H. pylori produced only a 5% reduction in dyspepsia. This small benefit had no impact on quality of life.

Adult↗
PubMed2000

Binding of phosphate with a simple hexaaza polyammonium macrocycle.

A mixture of dihydrogen phosphate and phosphoric acid has been crystallized with a hexaprotonated 26-membered polyammonium macrocycle, 1,4,7,14,17,20-hexaazacyclohexacosane, as the counterion. The complex crystallizes in the monoclinic space group P2(1)/c with unit cell parameters of a = 10.006(2) A, b = 12.525(1) A, c = 19.210(2) A, beta = 102.91(1) degrees, and V = 2346.6(5) A3. The hexaprotonated macrocycle is located on a crystallographic center of inversion and is surrounded by eight phosphate anions. Six of the phosphates are dihydrogen phosphates (H2PO4-), and the other two are neutral phosphoric acid molecules. Intricate hydrogen-bonding networks, involving the anionic and neutral phosphates and the protonated macrocycle, dominate the crystal lattice. Potentiometric studies using NaCl as the supporting electrolyte indicate high formation constants for the triprotonated macrocycle, H3L3+, with PO4(3-) at pH approximately 9.5 (log K = 4.55(4)), for the tetraprotonated macrocycle, H4L4+, with monohydrogen phosphate, HPO4(2-), at pH approximately 8.0 (log K = 6.01(3)), and for ditopic complexes with H5L5+ and H6L6+ and dihydrogen phosphate, H2PO4-, at pH approximately 4.0 (log K = 6.16(6)) and pH approximately 2.5 (log K = 6.44(5)), respectively. The ditopic behavior in the simple polyazamacrocycle receptor is a somewhat unusual occurrence, as is the finding of phosphoric acid species in the crystal structure.

Journal Article↗
PubMed2000

Prognostic factors associated with pressure sore development in the immediate post-operative period.

The purpose of this study was to identify variables associated with post-operative pressure sore incidence. The data were derived from a sequential, double triangular, randomised, blinded, controlled trial of the intra-operative use of a visco-elastic polymer pad conducted at two centres. Of 446 surgical patients recruited the main endpoint was assessed for 416 patients of whom 65 (15.6%) had a post-operative pressure sore. Analysis determined that the probability of a patient developing a pressure sore was associated with increased number of hypotensive episodes and mean core temperature during surgery, and reduced mobility Day 1 post-operatively. The development of a probability equation illustrates the future potential of prognostic factor research in the development of risk assessment tools and their application within clinical settings.

Aged↗
PubMed2000

The effectiveness of omeprazole, clarithromycin and tinidazole in eradicating Helicobacter pylori in a community screen and treat programme. Leeds Help Study Group.

INTRODUCTION: Helicobacter pylori screening and treatment has been proposed as a cost-effective method of preventing gastric cancer. AIM: To assess, in a randomized controlled trial, the efficacy of therapy in eradicating H. pylori as part of a screening programme, and to report the adverse events associated with this strategy. METHODS: Subjects between the ages of 40-49 years were randomly selected from the lists of 36 primary care centres. Participants attended their local practice and H. pylori status was determined by 13C-urea breath test. Infected subjects were randomized to receive omeprazole 20 mg b.d., clarithromycin 250 mg b.d. and tinidazole 500 mg b.d. for 7 days (OCT) or identical placebos. Eradication was determined by a 13C-urea breath test 6 months and 2 years after the first visit. Successful eradication was defined as two negative 13C-urea breath tests or one negative and one missing test. Adverse events and compliance were assessed at the 6-month visit. RESULTS: A total of 32 929 subjects were invited to attend, 8407 were evaluable, and 2329 (28%) of these were H. pylori-positive. A total of 1161 subjects were randomized to OCT and 1163 to placebo; over 80% returned for a repeat 13C-urea breath test on at least one occasion. The eradication rates in those allocated to OCT were as follows: intention-to-treat, 710 out of 1161 (61%; 95% confidence interval: 58-64%); evaluable 710 out of 967 (73%; 95% CI: 71-76%); took all medication 645 out of 769 (84%; 95% CI: 81-87%). Adverse events occurred in 45% of the treatment group and in 18% of the placebo group (relative risk 2.5; 95% CI: 2.1-2.9). Compliance, male gender, no antibiotic prescription in the subsequent 2 years and experiencing a bitter taste with the medication were independently associated with treatment success. CONCLUSIONS: The OCT regimen has an eradication rate of 61% in intention-to-treat analysis and is therefore less successful in treating H. pylori as part of a screening programme compared with hospital studies in dyspeptic patients.

Administration, Oral↗
PubMed2000

Large-scale cDNA analysis reveals phased gene expression patterns during preimplantation mouse development.

Little is known about gene action in the preimplantation events that initiate mammalian development. Based on cDNA collections made from each stage from egg to blastocyst, 25438 3'-ESTs were derived, and represent 9718 genes, half of them novel. Thus, a considerable fraction of mammalian genes is dedicated to embryonic expression. This study reveals profound changes in gene expression that include the transient induction of transcripts at each stage. These results raise the possibility that development is driven by the action of a series of stage-specific expressed genes. The new genes, 798 of them placed on the mouse genetic map, provide entry points for analyses of human and mouse developmental disorders.

Animals↗
PubMed1999

Molecular studies in 20 submicroscopic neurofibromatosis type 1 gene deletions.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder characterized by a marked variability in expression. A more severe phenotype is frequently observed in the group of patients carrying a large NF1 deletion. To study the extent of the microdeletion in these NF1 patients, we generated a partial physical map of the NF1 flanking region. We describe seven PACs and three new polymorphic dinucleotide repeats located outside the NF1 gene and analyzed 20 unrelated individuals with an NF1 microdeletion in a collaborative study. We detected one individual with a substantially smaller deletion including only the NF1 gene and its three embedded genes. In the other 19 patients, the deletion extended at least 1 Mb. The parental origin of the deletion was determined in 15 individuals and was maternal in 13 and paternal in two cases. The new molecular tools described here can be used to unequivocally diagnose a possible extragenic extension of an NF1 deletion.

Base Sequence↗
PubMed1999

An international network for evaluating neuroprotective therapy after severe birth asphyxia.

Animal studies have shown great promise in their applicability to potentially neuroprotective therapies for severe birth asphyxia in human babies. It is now necessary to consider a strategy to evaluate some or all of these techniques within the context of human neonatal randomized control trials (RCT). We have set up a pilot study for an international RCT of mature babies with severe asphyxia (defined by an Apgar score of 5 or less at 10 minutes) and have shown that we can recruit from 120 centers in 17 countries an average of three babies a week, which is the required number to undertake a study over a 2-year period with sufficient power to show a significant improvement in outcome. Particular attention must be given in future studies to the size of improvement in outcome required, generalizability of entry criteria, and the appropriate measure of functional outcome in treated babies.

Animals↗
PubMed1999

Neither nociceptin nor its receptor are present in human synovial fluid or tissue.

Our aim was to identify the nociceptin receptor and its endogenous ligand, nociceptin, in human peripheral tissue. Synovial tissue was obtained from 11 patients (ASA I-III, 66-84 yr) undergoing elective total knee replacement. Synovial fluid was obtained from another 10 patients (ASA I-III, 57-81 yr). Fluid was mixed with trifluoroacetic acid and the tissue with isopentone before freezing at -70 degrees C. Nociceptin receptor identification was performed using a [3H]nociceptin binding assay and nociceptin detection by radioimmunoassay. There was no specific [3H]nociceptin binding to knee synovial tissue and radioimmunoassay did not detect nociceptin. Neither the nociceptin receptor nor nociceptin was found in human synovial tissue or fluid.

Aged↗
PubMed1999

Amputation prevention by vascular surgery and podiatry collaboration in high-risk diabetic and nondiabetic patients. The Operation Desert Foot experience.

OBJECTIVE: To describe a unique multidisciplinary outpatient intervention for patients at high risk for lower-extremity amputation. RESEARCH DESIGN AND METHODS: Patients with foot ulcers and considered to be high risk for lower-extremity amputation were referred to the High Risk Foot Clinic of Operation Desert Foot at the Carl T. Hayden Veterans Affairs' Medical Center in Phoenix, Arizona, where patients received simultaneous vascular surgery and podiatric triage and treatment. Some 124 patients, consisting of 90 diabetic patients and 34 nondiabetic patients, were initially seen between 1 October 1991 and 30 September 1992 and followed for subsequent rate of lower-extremity amputation. RESULTS: In a mean follow-up period of 55 months (range 3-77), only 18 of 124 patients (15%) required amputation at the level of the thigh or leg. Of the 18 amputees, 17 (94%) had type 2 diabetes. The rate of avoiding limb loss was 86.5% after 3 years and 83% after 5 years or more. Furthermore, of the 15 amputees surviving longer than 2 months, only one (7%) had to undergo amputation of the contralateral limb over the following 12-65 months (mean 35 months). Compared with nondiabetic patients, patients with diabetes had a 7.68 odds ratio for amputation (95% CI 5.63-9.74) (P < 0.01). CONCLUSIONS: A specialized clinic for prevention of lower-extremity amputation is described. Initial and contralateral amputation rates appear to be far lower in this population than in previously published reports for similar populations. Relative to patients without diabetes, patients with diabetes were more than seven times as likely to have a lower-extremity amputation. These data suggest that aggressive collaboration of vascular surgery and podiatry can be effective in preventing lower-extremity amputation in the high-risk population.

Adult↗
PubMed1998

A sequential randomised controlled trial comparing a dry visco-elastic polymer pad and standard operating table mattress in the prevention of post-operative pressure sores.

Four hundred and forty-six general, vascular and gynaecological surgical patients were recruited to a two centre, double triangular sequential randomised controlled trial to compare the post-operative pressure sore incidence in patients positioned on the standard operating table mattress with those positioned on the dry visco-elastic polymer pad (Action Products Inc.). Two hundred and twenty two patients were randomised to the experimental group and 224 to the standard mattress. The main endpoint failure rate (a pressure sore) was found to be 11% (22/205) for patients allocated to the dry visco-elastic polymer pad and 20% (43/211) for patients allocated to the standard operating table mattress. There was a significant reduction in the odds of developing a pressure sore on the dry visco-elastic polymer pad as compared to the standard, [symbol see text] = 0.46 with 95% confidence interval of (0.26, 0.82), P = 0.010. The adjusted point estimates of the probability of developing a pressure sore on the dry visco-elastic polymer pad and the standard operating table mattress were 0.11 and 0.21 respectively.

Aged↗
PubMed1998

The Leeds Dyspepsia Questionnaire: a valid tool for measuring the presence and severity of dyspepsia.

BACKGROUND: There is currently no validated questionnaire that assesses both the presence and severity of dyspepsia. AIM: To develop the Leeds Dyspepsia Questionnaire (LDQ) as a measure of the presence and severity of dyspepsia, and to assess the validity, reliability and responsiveness of this instrument. METHODS: Unselected patients attending either a hospital dyspepsia clinic or a general practice surgery were interviewed by a trained gastroenterologist or a general practitioner on the presence and severity of dyspepsia. This opinion was compared with the results of the nurse-administered LDQ. Test-retest reliability was assessed by the same research nurse re-administering the LDQ 4-7 days after the initial visit in a subgroup of hospital patients. In a further subgroup of patients one researcher interviewed the patients and a second researcher re-administered the LDQ within 30 min to evaluate inter-rater reliability. The responsiveness of the LDQ was measured by repeating it in patients with endoscopically proven peptic ulcer or oesophagitis 1 month after receiving appropriate therapy. RESULTS: The LDQ was administered to 99 general practice and 215 hospital patients. In the GP population 41/98 (42%) had dyspepsia according to the GP and the LDQ had a sensitivity of 80% (95% CI: 65-91%) and a specificity of 79% (95% CI: 66-89%). The weighted kappa statistic for the agreement between the LDQ and the clinician for the severity of dyspepsia was 0.58 in the GP population and 0.49 in hospital patients. The kappa statistic for test-retest reliability was 0.83 in 107 patients. The LDQ had excellent inter-rater reliability with a kappa statistic of 0.90 in 42 patients. The median LDQ score fell from 22.5 (range 9-36) to 4.5 (range 0-27) in 12 patients 1 month after receiving appropriate therapy (Wilcoxon signed rank test, P < 0.0001). CONCLUSION: The LDQ is a valid, reliable and responsive instrument for measuring the presence and severity of dyspepsia.

Adolescent↗
PubMed1998

Field sensitivity of targeted neonatal hearing screening using the Nottingham ABR Screener.

OBJECTIVE: A population of children having bilateral moderate to profound hearing impairment was investigated to find out the number who passed (false negatives) and who failed (true positives) a screening test based on the auditory brain stem response (ABR). DESIGN: This study of the ABR is a parallel report to Lutman, Davis, Fortnum, and Wood (1997), where the transient evoked otoacoustic emission was examined on a similar but not identical population of at-risk neonates. Hearing screening was undertaken in at-risk neonates (targeted screening) at seven hospitals in the UK using the Nottingham ABR Screener. During the period from January 1988 to December 1993, a total of 6983 neonates had been tested. Assessment of audiological records from the participating centers ascertained that 201 children born between January 1988 and December 1993 had hearing threshold levels in both ears of 50 dB or more, averaged over the speech frequencies 0.5, 1, 2, and 4 kHz. Of these, 51 had completed the ABR screening test. Examination of the ABR records, which included both machine and visual scoring, indicated whether they had passed or failed the screening test. RESULTS: Forty-six of the 51 hearing impaired babies failed the neonatal ABR screen either on one or both ears (five false negatives), and 42 failed the test on both ears (nine false negatives). This resulted in field sensitivities of 90% and 82%, respectively. Two cases of suspected progressive hearing loss have been included in the numbers of false negative results. The percentage of babies passing the screen on both ears and subsequently having normal hearing (specificity) is typically 93%. CONCLUSIONS: Neonatal hearing screening in an at-risk population using a highly automated ABR test is a viable and effective tool for identification of hearing impairment. Although the field sensitivity of the test is high, it is unable to identify all babies with a criterion level of hearing loss. There are a number of possible explanations as to the origin of false negative results: configuration of the pure-tone audiogram, a progressive hearing loss, acquired sensorineural or conductive loss, retrocochlear deafness, or an incorrect interpretation of the screening test. Passing a neonatal screening test, therefore, does not exclude the possibility of subsequent hearing impairment and highlights the need for further surveillance.

Auditory Threshold↗
PubMed1998

Anomalous screening outcomes from click-evoked otoacoustic emissions and auditory brainstem response tests.

Transiently evoked otoacoustic emissions (TEOAE) and auditory brainstem response (ABR) tests were used in parallel to screen 862 neonates with risk factors for hearing loss. Seven neonates (0.81%) passed on TEOAE screen yet failed on ABR in one ear (six neonates) or both ears (one neonate). This combination of results has been termed 'anomalous'. Examination of audiometric results obtained on follow-up shows that in one ear of one neonate the result was consistent with the later confirmed audiogram shape. The explanation for the anomalous results in the remaining ears is unclear although neural maturation and the effects of hyperbilirubinaemia are possibilities. There were no instances of progressive or retrocochlear hearing loss identified. None of the seven neonates had better ear hearing loss of > or = 40 dB on long term follow-up.

Acoustic Stimulation↗
PubMed1998

Refsum's disease. A unique case.

Refsum's disease, or heredopathia atactica polyneuritiformis, is a peroxisomal disorder leading to the accumulation of phytanic acid throughout the body. It affects sensory and motor neurons and the skeletal system. Peripheral neuropathy, ataxia, blindness, deafness, and skeletal hyperostosis are significant findings used in the diagnosis of the disease.

Aged↗