Search PubMed⌕ Search

Biomedical subjects

S Davies

Publications and source records attributed to S Davies.

At least 163 records · Page 9Linked to original sources
PubMed1998

Quantification of ammonia in human breath by the selected ion flow tube analytical method using H30+ and 02+ precursor ions.

We show how our selected ion flow tube mass spectrometric technique for trace gas analysis can be used to determine the concentrations of ammonia in alveolar breath from single exhalations using both H30+ and 02+ precursor ions for chemical ionization. Thus, data are presented of the alveolar ammonia concentrations in the breath of six healthy volunteers following the ingestion of a liquid protein meal, which show that consistent values are obtained using these two precursor ions. Alveolar breath ammonia concentrations (which range from 200 to 1750 ppb in these individuals) are compared with those obtained from bag samples of breath from the same individuals.

Ammonia↗
PubMed1998

Vinorelbine in the treatment of lymphoma.

Seventeen patients with previously treated Hodgkin's disease or non-Hodgkin's lymphoma (NHL) were treated with single-agent vinorelbine (Navelbine Pierre-Fabre Medicament) in an open study to assess the activity of this new-generation vinca alkaloid. Responses were obtained in four out of eight patients with Hodgkin's disease and four out of nine patients with NHL, including four patients who had been previously treated with high-dose therapies. Toxicity was very mild. The study demonstrates worthwhile activity and justifies the inclusion of vinorelbine in combination therapies for lymphoma.

Adult↗
PubMed1998

Influence of GB virus C viraemia on the clinical, virological and histological features of early hepatitis C-related hepatic disease.

BACKGROUND/AIMS: GB virus C is a newly described RNA virus. The aims of this study were to determine the prevalence of GB virus C infection in patients with chronic type C hepatitis and to examine the clinical, virological and histological features in hepatitis C and GB virus C co-infected patients. METHODS/RESULTS: One hundred and sixty patients with hepatitis C infection were studied. GBV-C RNA was detected in 33/160 (20.6%) patients; co-infected patients with hepatitis C and GB virus C infection were significantly younger (p=0.04). No difference was found between the two groups according to gender and biochemical parameters. Seventy-two of the 160 patients, for whom a liver tissue specimen taken simultaneously with the serum was available and who had compensated liver disease, were studied separately. The source of infection, duration of infection, HCV genotype and HCV RNA concentrations did not differ between 15/72 patients with dual infection and 57/72 with hepatitis C infection alone. Patients with co-infection had significantly higher degrees of portal and periportal inflammation (p=0.0006 and 0.01, respectively). No difference was observed in parenchymal activity score or extent of fibrosis. CONCLUSIONS: These results indicate a relatively high prevalence of GB virus C infection in younger patients with chronic hepatitis C, suggesting a common route of transmission. Although GB virus C co-infection does not alter the biochemical and virological profile of patients with HCV hepatitis, there is an association between GB virus C and hepatitis C viraemia and portal and periportal inflammation.

Adult↗
PubMed1998

Safety pictograms: are they getting the message across?

This study set out to investigate the role of pictograms in conveying consumer safety information. The experimental work was carried out in two parts. The first part investigated UK comprehension levels of 13 product related pictograms. A new method of judging levels of comprehension of the pictograms was developed. In general the pictograms surveyed were found to be poorly understood, particularly those which were abstract in nature. The second part of the research investigated the effect of different warning styles on noticeability and intended compliance. This was tested using the new European Standard pictogram developed to convey the small parts warning on toys. The effect on parents' intended purchase decisions of different pictograms and or text messages was investigated. Results indicated that parents' decisions on toy suitability were influenced by the perceived hazardousness of the product rather than warnings, regardless of their design. The paper discusses the advantages and limitations of pictograms as a method for conveying consumer information and makes recommendations for their effective use.

Consumer Product Safety↗
PubMed1998

Evidence for a non-associative model of the acquisition of a fear of heights.

Theories that fear results from previous traumatic experience (i.e. conditioning theories) have enjoyed widespread support for over half a century. Recent research, however, has cast doubt on the validity of these models in some specific phobias. Two studies on the etiology of height phobia have obtained findings consistent with a non-associative, evolutionary explanation of fear acquisition (Menzies and Clarke, 1993a, Behaviour Research and Therapy, 31, 355-365; Menzies and Clarke, 1995a, Behaviour Research and Therapy, 33, 795-805). Unfortunately, the retrospective nature of these studies limits the conclusions that can be drawn from these data. Like all retrospective research, these studies depend on adult subjects imperfect ability to recall conditioning events that may have occurred many years earlier. The present investigation overcomes these methodological shortcomings by examining the relationship between putative conditioning events before the age of 9 yr and the presence of height fear at ages 11 and 18 yr in a large birth cohort studied longitudinally. To our knowledge this is the first study that has prospectively examined the relationship between relevant traumatic events early in life and the onset of height fear in late adolescence. No positive relationship was found between a history of falls resulting in injury (i.e. fracture, dislocation, intracranial injury or laceration) before the age of 9 and fear of heights at age 11 or 18. Interestingly, falls resulting in injury between the ages of 5 and 9 occurred more frequently in those without a fear of heights at 18 (P < 0.01)--a finding in the opposite direction to that predicted by conditioning theory but consistent with non-associative theories of fear acquisition. In general, the results provide strong support for non-associative models of fear and are difficult to reconcile with conditioning theories.

Accidental Falls↗
PubMed1998

Sustained reduction in the carriage of Neisseria meningitidis as a result of a community meningococcal disease control programme.

The effect of a community intervention programme of antibiotics and meningitis vaccine on pharyngeal carriage of Neisseria meningitidis was investigated. Carriage rates were determined in pupils at both secondary schools (ages 11-18 years) included in the community intervention programme and compared with two schools outside the area matched for socio-economic status. A total of 1869 pupils were studied 6 months after the programmes, and 2457 pupils after 11 months. Six months after the programme was completed there was a 72% reduction in pharyngeal carriage of Neisseria meningitidis in pupils attending the schools in the intervention area compared with pupils in the control schools. After 11 months this difference persisted in the 11-14 age group but not in the 15-18 age group. No resistance to the antibiotics used in the programme was found. A community intervention programme of antibiotics and vaccine for the control of meningococcal disease led to a long-term reduction in Neisseria meningitidis carriage in some age groups.

Adolescent↗
PubMed1998

The efficacy of FP 736-04 in experimental liver cirrhosis.

PURPOSE: To determine whether the uptake of FP 736-04, a hepatocyte-specific CT contrast agent, is influenced by cirrhotic changes in the liver. MATERIAL AND METHODS: Liver cirrhosis was induced by bile duct ligation (BDL) in Sprague-Dawley rats. Seventy-four animals were divided into three groups comprising: rats with acute BDL; rats with chronic BDL; and normal controls. CT was performed after i.v. infusion of FP 736-04 or saline at a dose of 2 ml/kg b.w., and the mean attenuation in the liver and spleen was measured. The livers from the chronic BDL group were taken for histopathological examination and the extent of the disease was graded according to an arbitrary scale. RESULTS AND CONCLUSION: There was a significant reduction of the native liver attenuation in both chronic and acute BDL groups as compared with the normal controls. FP 736-04 was taken up by the liver parenchyma with a similar degree of enhancement in all three groups.

Animals↗
PubMed1998

Imipramine in the treatment of social phobia.

We report the results of an 8-week open trial of imipramine in 15 patients with social phobia. Nine patients completed the trial; six dropped out early because of adverse effects. The mean reduction in the Liebowitz Social Anxiety Scale was 15% and 18% for the intent-to-treat and completer groups, respectively; the overall response rate (based on the Clinical Global Impression Scale of 1 or 2, very much or much improved) was 20% (3/15) and 22% (2/9), respectively. The results from this open trial do not support the efficacy of imipramine as a treatment for social phobia.

Adult↗
PubMed1998

Post-ERCP pancreatitis and hyperamylasaemia: the role of operative and patient factors.

BACKGROUND AND AIM: Pancreatitis and hyperamylasaemia are common complications of ERCP and this study was designed to explain which operative and patient factors predispose to them. PATIENTS AND METHODS: A 1 year prospective study of consecutive patients in a single operator centre with detailed attention to technical factors and the findings. RESULTS: Four hundred and thirty ERCPs were performed. Pancreatitis occurred in 12 cases (2.8%). Amylase results were available in 407 cases; 17 were excluded because of pre-operative hyperamylasaemia (n = 5) and because of pancreatitis (n = 12). Of the remaining 390, 30 (7.7%) had hyperamylasaemia. Pancreatitis and hyperamylasaemia usually occurred after difficult procedures in which pancreatography was achieved. Smaller common bile-ducts, pre-cut papillotomy and some preoperative indications also significantly increased the risk of pancreatitis, while prior papillotomy was protective. Pancreatitis occurred in patients with a younger median age (52.5 vs 68.0; P < 0.05) and was more common in women (F:M = 11:1 vs 241:177; P < 0.05). CONCLUSION: Operative factors are, in part, responsible for the development of pancreatitis and hyperamylasaemia but the age and sex of the patient also appear to be important.

Adult↗
PubMed1998

Dental caries and changes in dental anxiety in late adolescence.

Little is known about changes in dental anxiety with ageing and their association with changes in oral health. This study examined the relationship between changes in dental caries experience and dental anxiety from 15 to 18 years of age among adolescent participants in the Dunedin Multidisciplinary Health and Development Study. Dental anxiety was estimated using the Corah Dental Anxiety Scale (DAS), and individuals with a DAS score of 13+ were identified as being dentally anxious. Dental examinations were performed on 649 individuals at ages 15 and 18, and a DMFS score was computed for each. Caries prevalence among those who were dentally anxious at both 15 and 18 years was significantly higher than for those who were not at either age. Regression analysis revealed that dental anxiety predicted caries incidence between ages 15 and 18 years. Dental anxiety is likely to be a significant predictor of dental caries experience, and may be a risk factor for dental caries incidence.

Adolescent↗
PubMed1998

Comparison of gas chromatography and mineralization experiments for measuring loss of selected polychlorinated biphenyl congeners in cultures of white rot fungi.

Two methods were used to compare the biodegradation of six polychlorinated biphenyl (PCB) congeners by 12 white rot fungi. Four fungi were found to be more active than Phanerochaete chrysosporium ATCC 24725. Biodegradation of the following congeners was monitored by gas chromatography: 2,3-dichlorobiphenyl, 4,4'-dichlorobiphenyl, 2,4',5-trichlorobiphenyl (2,4',5-TCB), 2,2',4,4'-tetrachlorobiphenyl, 2,2',5,5'-tetrachlorobiphenyl, and 2,2',4,4',5,5'-hexachlorobiphenyl. The congener tested for mineralization was 2,4',5-[U-14C]TCB. Culture supernatants were also assayed for lignin peroxidase and manganese peroxidase activities. Of the fungi tested, two strains of Bjerkandera adusta (UAMH 8258 and UAMH 7308), one strain of Pleurotus ostreatus (UAMH 7964), and Trametes versicolor UAMH 8272 gave the highest biodegradation and mineralization. P. chrysosporium ATCC 24725, a strain frequently used in studies of PCB degradation, gave the lowest mineralization and biodegradation activities of the 12 fungi reported here. Low but detectable levels of lignin peroxidase and manganese peroxidase activity were present in culture supernatants, but no correlation was observed among any combination of PCB congener biodegradation, mineralization, and lignin peroxidase or manganese peroxidase activity. With the exception of P. chrysosporium, congener loss ranged from 40 to 96%; however, these values varied due to nonspecific congener binding to fungal biomass and glassware. Mineralization was much lower, </=11%, because it measures a complete oxidation of at least part of the congener molecule but the results were more consistent and therefore more reliable in assessment of PCB biodegradation.

Basidiomycota↗
PubMed1998

Peutz-Jeghers disease: most, but not all, families are compatible with linkage to 19p13.3.

A locus for Peutz-Jeghers syndrome (PJS) was recently mapped to chromosome 19p13.3. Each of 12 families studied was compatible with linkage to the marker D19S886. We have analysed 20 further families and found that the majority of these are consistent with a PJS gene on 19p13.3. Three families were, however, unlinked to 19p13.3 and none of the available PJS polyps from these families showed allele loss at D19S886. There were no obvious clinicopathological or ethnic differences between the 19p13.3 linked and unlinked families. There appears, therefore, to be a major PJS locus on chromosome 19p13.3 and the possibility exists of a minor locus (or loci) elsewhere.

Chromosomes, Human, Pair 19↗