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Biomedical subjects

A Fraser

Publications and source records attributed to A Fraser.

At least 73 records · Page 4Linked to original sources
PubMed1998

Helicobacter pylori is killed by nitrite under acidic conditions.

BACKGROUND: Due to the expression of urease, Helicobacter pylori is able to establish itself in the human stomach under acidic conditions. A novel host defence mechanism was recently proposed, suggesting that the formation of salivary nitrite in symbiosis with facultative anaerobic bacteria in the oropharynx, is aimed at enhancing the antimicrobial activity of gastric juice. AIMS: To investigate whether the addition of nitrite in physiological concentrations influences the resistance of H pylori to acid. METHODS: H pylori cultured from fresh gastric Biopsy specimens was exposed for 30 minutes to normal saline and to HCl/KCl buffer (0.2M) at pH 2 with urea (5 mM) added. The influence of potassium nitrite (50-1000 mumol/l) on bacterial survival was determined. RESULTS: Addition of nitrite (1 mM) to acidic solutions (pH 2) resulted in complete kill of H pylori within 30 minutes exposure time whereas acid alone allowed the organism to survive (p < 0.001). The antimicrobial effect of nitrite at pH 2 against H pylori was dose dependent and complete kill of organisms occurred at concentrations > or = 500 mumol/l. CONCLUSION: Acidified nitrite has anti-bacterial activity against H pylori. This should prompt further research into the effect of salivary nitrite on the survival of H pylori in the human stomach.

Anti-Bacterial Agents↗
PubMed1998

Abuse histories of psychiatric inpatients: to ask or not to ask?

OBJECTIVE: The literature suggests that a high prevalence of a history of sexual and physical abuse among psychiatric inpatients is found when researchers inquire about abuse directly, but that relatively low rates are found in medical records. This study examined rates of reported abuse among patients who were and were not asked about abuse at admission. METHODS: The medical records of 100 consecutive admissions to an urban general hospital in New Zealand were examined after the introduction of a new admission form with a section inquiring about abuse. Use of the new admission form was recommended but not mandatory. RESULTS: The abuse section of the new form was completed for only 17 of the 53 patients with whom the new form was used. Review of the medical records of all 100 consecutive admissions revealed a prevalence rate of 32 percent for one or more of the four types of abuse. However, 14 of the 17 patients (82 percent) who were asked directly about abuse reported having experienced abuse. Nonsignificant trends suggested that male gender and being more disturbed or disturbing may be negatively related to the probability of being asked about abuse. Men may be particularly unlikely to disclose childhood abuse if not asked directly. CONCLUSIONS: The authors recommend including inquiry about abuse in standardized admission procedures and providing inpatient staff with training in how and when to ask patients about abuse and how to effectively follow up affirmative responses.

Adult↗
PubMed1998

Staff response to abuse histories of psychiatric inpatients.

OBJECTIVE: In the context of numerous studies demonstrating that a significant proportion of psychiatric inpatients have been sexually or physically abused at some point in their lives this study ascertained the responses of staff in a psychiatric inpatient unit to knowledge that patients had been subjected to sexual or physical abuse, in childhood or adulthood. METHOD: The medical records of 100 consecutive admissions were examined. Staff response was measured in terms of: (i) acquiring information about previous treatment for, or disclosure of, abuse; (ii) providing information, support or counselling during hospitalisation; (iii) reporting to legal authorities; and (iv) referring for ongoing abuse counselling. RESULTS: Of the 32 patients who were documented as having disclosed abuse 11 files included documentation of previous treatment or disclosure; none were reported to have received support, counselling or information while in hospital; and three referrals were made for ongoing counselling. None of the 52 separate instances of abuse were reported to the authorities. Demographic, diagnostic, clinical and treatment variables, as well as the four abuse categories, were analysed for possible linkage to probability of staff response in each of the four response categories. CONCLUSIONS: It was hypothesised that the low staff response rate is not unique to the particular unit evaluated here. Recommendations are offered regarding the need for unit policies ensuring routine abuse inquiry and for staff training about how to respond to abuse disclosures.

Adult↗
PubMed1997

Mental health. Careering around.

An orientation exercise provided a structured, supervised induction for practice based community psychiatric nurses. The exercise also provided community perspectives on need. The same process could be used for other new primary healthcare workers.

Career Mobility↗
PubMed1997

Country-specific constancy by age in cagA+ proportion of Helicobacter pylori infections.

Helicobacter pylori strains may be either cagA+ or cagA-, and in logitudinal studies, infection with a cagA+ strain has been associated with increased risk for the development of atrophic gastritis and cancer of the distal stomach. We sought to determine the relative proportion of strains producing CagA in different geographic locales, and the extent to which CagA seroprevalence varied in countries with different gastric and esophageal cancer rates. Using an enzyme-linked immunosorbent assay (ELISA) to detect serum IgG to CagA, we examined sera from 468 asymptomatic H. pylori-infected adults from Canada, Peru, China, Thailand, The Netherlands and 3 different ethnic groups in New Zealand. The CagA seroprevalence in Peru and Thailand (82.2% and 78.8%, respectively) were each substantially higher than for the Chinese (37.9%), Canadian (41.9%), Dutch (39.0%) and New Zealand (28.2%) subjects, but within each population, rates were relatively constant across gender and age groups. Reported gastric but not esophageal cancer rates for the 8 studied populations were significantly associated with H. pylori seroprevalence. Variation in CagA positivity rates was not significantly associated with variation in either gastric or esophageal cancer rates. Our data suggest that CagA seroprevalence is not the major factor influencing gastric cancer rates.

Adult↗
PubMed1997

CED-4 induces chromatin condensation in Schizosaccharomyces pombe and is inhibited by direct physical association with CED-9.

BACKGROUND: Three principal genes are involved in developmental programmed cell death (PCD) in the nematode worm Caenorhabditis elegans. The ced-3 and ced-4 genes are both required for each PCD, whereas ced-9 acts to prevent the death-promoting actions of these genes in cells that are destined to survive. Vertebrate homologues of both ced-3 and ced-9 have been identified as the genes encoding the caspase cysteine proteases and the Bcl-2 family, respectively. In contrast, no vertebrate homologue of ced-4 is known. The CED-3/caspases are important effectors of apoptosis that are presumed to act by cleaving specific target substrates. However, the molecular functions of the CED-9/Bcl-2 and CED-4 proteins are unknown. The unicellular yeast Schizosaccharomyces pombe shares many general cellular properties with metazoa, but has no identified cell suicide machinery. We have therefore used S. pombe as a naive model cell system in which to examine the biological effects of cell-death proteins. RESULTS: Induction of wild-type ced-4 expression in S. pombe resulted in rapid focal chromatin condensation and lethality. Mutation of the putative nucleotide-binding P-loop motif of CED-4 (K165Q) eliminated the lethal phenotype. Immunolocalization of CED-4 to the condensed chromatin suggested that the phenotype may result from an intrinsic activity of CED-4. Co-expression of ced-9 prevented CED-4-induced chromatin condensation and lethality, and caused the relocalization of CED-4 to endoplasmic reticulum and outer mitochondrial membranes. A direct interaction between CED-4 and CED-9 was confirmed by yeast two-hybrid analysis. CONCLUSIONS: Using S. pombe as a model system in which to assay CED-4 function, we have identified a potential direct role for CED-4 in chromatin condensation. Chromatin condensation is a ubiquitous feature of metazoan apoptosis that has yet to be linked to an effector. The CED-9-mediated rescue of CED-4-induced lethality in this system and the interaction of the two proteins in the yeast two-hybrid analysis suggest that CED-9 inhibits CED-4 action by direct physical association.

Animals↗
PubMed1997

Autoantibodies to oxidized low density lipoprotein: the relationship to low density lipoprotein fatty acid composition in diabetes.

Autoantibodies to oxidized low density lipoprotein have been shown to be an independent predictor of the progression of carotid atherosclerosis. This study examines the relationship between low density lipoprotein fatty acid composition and autoantibodies to both malondialdehyde-modified and copper-oxidized low density lipoprotein in non-diabetic patients with (n = 17), and without (n = 18), definite evidence of previous myocardial infarction. The third group were non-insulin-dependent diabetic patients with no evidence of atherosclerosis (n = 15) and the fourth group were patients with non-insulin-dependent diabetes (n = 17) who had definite evidence of previous myocardial infarction. Fatty acids were measured by gas-liquid chromatography. Antibodies to malondialdehyde-modified low density lipoprotein and copper-oxidized low density lipoprotein were determined by an ELISA method. Autoantibodies to copper-oxidized low density lipoprotein were significantly higher in the non-diabetic patients with heart disease when compared to any other group (p < 0.05). Autoantibodies to malondialdehyde-modified low density lipoprotein were significantly higher in the non-diabetic subjects with heart disease and in both diabetic groups compared to non-diabetic subjects without coronary heart disease (p < 0.05). Linoleic acid (%) in low density lipoprotein did not differ between groups groups but arachidonic acid (%) was significantly lower in both diabetic and non-diabetic patients with coronary heart disease (p < 0.05). The diabetic patients with low antibodies had 39.6 +/- 2.2% polyunsaturated fatty acids in their low density lipoprotein while diabetic patients with high antibodies had 46.7 +/- 1.2% polyunsaturates in their low density lipoprotein (p < 0.01). This study confirms the association between antibodies to oxidized low density lipoprotein and coronary heart disease and shows raised low density lipoprotein antibody levels in diabetic patients with and without demonstrable atherosclerosis. In the diabetic patients, those with high antibody levels had high polyunsaturated fatty acid levels in their LDL suggesting a possible role for dietary intervention.

Aged↗
PubMed1997

Evidence for ethnic tropism of Helicobacter pylori.

Helicobacter pylori infection in humans is linked to gastritis, gastric and duodenal ulcers, and gastric cancer. Peptic ulcer disease, as distinct from chronic asymptomatic infection, is strongly associated with expression of bacterial virulence markers, including a major antigen, CagA, and the vacuolating cytotoxin VacA. We have previously described significant differences in colonization rates, independent of socioeconomic status, among ethnic groups in New Zealand. To evaluate relative risks for peptic ulcer disease, we examined the frequency of two virulence markers in H. pylori strains infecting these ethnic groups. Although these markers occurred significantly more frequently in strains isolated from Polynesians than in strains from Europeans, this frequency was not reflected in the incidence of peptic ulcer disease in the two groups. DNA fingerprinting of the urease gene showed that Polynesians are more frequently infected by a group of strains which are genetically distinct from those affecting European New Zealanders. Our data suggest that separate bacterial lineages may have evolved in parallel with race-specific specialization.

Antigens, Bacterial↗
PubMed1997

Repeat prescribing.

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Drug Interactions↗
PubMed1996

Screening for colorectal cancer: a survey of New Zealand general practitioners.

AIM: To determine the attitudes and reported behaviours of New Zealand general practitioners concerning colorectal cancer screening and diagnosis with special consideration of the use of faecal occult blood tests. METHOD: A postal survey of a random sample of 400 New Zealand general practitioners. RESULTS: The response rate to the survey was 63%. Most of the respondents did not support a screening programme for average risk patients but did support screening in high risk groups. General practitioners favoured a screening programme offered by themselves rather than a centrally organised screening programme. A majority of respondents agreed that there was a lack of clear guidelines and a need for education regarding screening for bowel cancer. CONCLUSION: Guidelines for colorectal cancer screening are required for New Zealand general practitioners. There appears to be a need for medical education concerning screening for colorectal cancer in particular and screening and prevention in general.

Adult↗
PubMed1996

Biochemistry of cell death.

Apoptosis is a common feature of the nervous system, occurring physiologically during development and pathologically in several diseases. In view of the latter, pathways that regulate apoptosis in neurones are of particular interest, and recent advances in this field implicate several signalling pathways in the induction of apoptosis, after withdrawal of nerve growth factor. Recent information drawn from both mammalian and invertebrate models enables us to assign components of the apoptotic pathway as either regulators or effectors.

Animals↗