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Biomedical subjects

J Fraser

Publications and source records attributed to J Fraser.

At least 91 records · Page 5Linked to original sources
PubMed1991

Structure and expression of the infA operon encoding translational initiation factor IF1. Transcriptional control by growth rate.

The cellular levels of the three translational initiation factors, IF1, IF2, and IF3, increase as a function of growth rate in parallel with those of ribosomes. Therefore both ribosomal and initiation factor gene expression is under metabolic control. To address how expression of the Escherichia coli gene for IF1, infA, is regulated, a 3-kilobase region of the genome surrounding infA was sequenced. The 5' and 3' termini of in vivo infA transcripts were defined by S1 nuclease mapping, and mRNA size was measured by Northern blot hybridization. The infA gene is transcribed by two promoters, P1 and P2, which generate transcripts of 525 and 330 nucleotides, apparently ending at the same rho-independent terminator. Analyses of operon and protein fusions to lacZ demonstrate that neither infA transcription nor translation is affected by high cellular levels of IF1. However, P2, but not P1, increases in activity as a function of the growth rate of the cell and is the dominant promoter in rich medium. Therefore, metabolic control of infA expression occurs exclusively at the level of transcription by the P2 promoter.

Amino Acid Sequence↗
PubMed1991

Ubiquitin gene expression: response to environmental changes.

It has previously been shown that the yeast ubiquitin genes UBI1, 2 and 3 are strongly expressed during the log-phase of batch culture growth, whereas the UBI4 gene is weakly expressed. We found that heat shock, treatment with DNA-damaging agents, starvation, and the feeding of starved cells all transiently induced UBI4. These results suggest that UBI4 is induced whenever a change in culture conditions dictates a dramatic shift in cellular metabolism, and that UBI4 expression returns to lower levels once cellular metabolism has adapted to the new conditions. In contrast, all of the treatments tested, except starvation, transiently repressed the UBI1, 2 and 3 genes. Although starvation also repressed UBI1, 2 and 3 its effect was not transient, and expression only recovered upon the addition of fresh media. These results, together with others presented here, suggest that high levels of UBI1, 2 and 3 expression are dependant upon ongoing cell growth, and that treatments which slow or stop growth repress their expression.

4-Nitroquinoline-1-oxide↗
PubMed1991

An empirical evaluation of the performance of antibody identification tasks.

Four empirical studies were conducted for better understanding of the nature of problem-solving activities by medical technologists and medical technology students when performing antibody identification tasks. The results indicated the importance of strategies that ensure the collection of converging evidence, as these strategies protect against the fallibility of commonly used heuristics and against errors due to simple slips. The results also indicate that not only do students make significant numbers of errors, but so do practicing technologists. In one of the studies covering a 1-year period, for instance, a group of 16 technologists made a total of 41 errors in 1057 cases. On the basis of these findings, several alternatives are proposed to reduce errors.

Adult↗
PubMed1991

Stomach cancer in New Zealand: time trends, ethnic group differences and a cancer registry-based case-control study.

Stomach cancer trends in New Zealand were examined. Age-standardized mortality and incidence rates have declined over the past four decades, as in other countries. Rates have been consistently higher for men, and for Maori. A cancer registry-based case-control study of 1016 male stomach cancer cases and 19,042 male controls with other cancers was also conducted, to evaluate the relationships between stomach cancer and specific occupations. Adjustment was made for age, ethnicity, socioeconomic level, and smoking status. When 22 occupational groups were examined, adjusted odds ratios (ORs) and 95% confidence intervals (95% Cls) were elevated above unity for only one group: forestry workers (OR 1.83, 95% Cl 1.01-3.32). When two large, heterogeneous groups were broken down into 15 subgroups, adjusted ORs and 95% Cls elevated above unity were found for three sub-groups: grain millers and related workers; brewers, wine and beverage makers; and field crop workers. These findings may be because of the multiple comparisons and subgroup analyses undertaken. Men who had ever smoked cigarettes were found to have an increased stomach cancer risk compared to those who had never smoked (adjusted OR 1.36, 95% Cl 1.15-1.60).

Case-Control Studies↗
PubMed1991

Inflight anxiety conditions presenting with "break-off" symptoms.

The psychological dimension of disorientation is explored through two experienced pilots who developed inflight anxiety conditions. These were associated with "break-off" symptoms, which are inflight sensations of separation from the ground, the environment, and the aircraft. Following extensive psychiatric and medical evaluations, one aviator was diagnosed as having agoraphobia without panic disorder, and the other as having an otherwise unspecified anxiety disorder. These patient reports demonstrate the need for the clinical aerospace medicine specialist to investigate inflight anxiety conditions for underlying neuropsychiatric disorders. The reports also contrast some of the historical aeromedical concepts with modern psychiatric diagnostic nomenclature.

Adult↗
PubMed1990

Risk factors for low birthweight in New Zealand, 1981-83.

This paper describes the patterns of risk factors for low birthweight in a cohort of New Zealand births. The trend of low birthweight with maternal age and parity was U-shaped. Maori mothers had the highest (79.38/1000 livebirths) and Pacific Island mothers the lowest (39.88/1000), rates of low birthweight infants. There was an indication that the risk for Pacific Island mothers was modified by the mother's place of birth. Compared to nonMaori nonPacific Island New Zealand born women, the risk was high for Pacific Island New Zealand born women (RR = 1.27, 95% CI 1.04-1.56), but low for nonNew Zealand born Pacific Island mothers (RR = 0.70, 95% CI 0.61-0.79). The risk for Maori mothers increased if the father was also of Maori ethnic origin. The risk of a low birthweight infant increased (p less than 0.001) with social class, and the rate was high among exnuptial births (75.25/1000 live births). The rates of low birthweight for nonMaori and Pacific Island births in the South Island were similar to those in the North Island, but among Maori births the rate in the South Island (RR = 0.64, 95% CI 0.51-0.82) was lower than in the North Island.

Adult↗
PubMed1990

Large-bowel cancer in the young: a national survival study.

Large-bowel cancer in young patients is reported to be a more aggressive and advanced disease at presentation and is believed to be associated with a relatively poor prognosis. Of 2420 patients registered in New Zealand (1968 to 1970), 131 were under 40 years of age and 2289 were over 40 years of age. The annual average incidence of treatable colorectal cancer in patients under 40 years of age was 2.36 per 100,000 and 82.93 in patients over 40 years of age. There were predominantly more females in both age groups with colonic tumors, 50:44 (female:male), and 759:652 (female:male). The rectal tumor male-to-female ratio of 1:0.68 in those over 40 years of age was reversed in those under 40 years of age (1:2.08). There was no significant difference in the subsite distribution of colorectal cancer between the two groups. There was a higher proportion of Stage 1 tumors in those under 40 years of age and a correspondingly higher proportion of Stage 2 tumors in those over 40 years of age. The overall crude and relative five-year survival rates for patients under 40 years of age were both 60 percent, whereas the crude rate for older patients was 42 percent, with a corresponding relative rate of 53 percent. Ten-year survival rates were generally higher in younger patients. From this study, there was no evidence to suggest that younger patients (less than 40 years old) with colorectal cancer had worse prognoses and did not survive as long as older patients (40 years and over).

Adult↗
PubMed1990

The repeated sequence CATT(A/T) is required for granulocyte-macrophage colony-stimulating factor promoter activity.

The hematopoietic growth factor GM-CSF (granulocyte-macrophage colony-stimulating factor) is expressed by activated but not resting T lymphocytes. Previously, we localized GM-CSF-inducible promoter activity to a 90-bp region of GM-CSF 5'-flanking sequences extending from bp -53 to +37. To more precisely identify the GM-CSF DNA sequences required for inducible promoter activity in T lymphocytes, we have performed mutagenesis within a region of GM-CSF 5'-flanking sequences (bp -57 to -24) that contains the repeated sequence CATT(A/T). Mutations that do not alter the repeated CATT(A/T) sequence do not eliminate inducible promoter activity, whereas mutation or deletion of either of the CATT(A/T) repeats eliminates all inducible promoter activity in T-cell lines and in primary human T lymphocytes. Thus, both copies of the direct repeat CATT(A/T) are required for mitogen-inducible expression of GM-CSF in T cells.

Animals↗
PubMed1990

Signature patterns of DNA restriction fragments of Helicobacter pylori before and after treatment.

The genomic DNA of Helicobacter pylori was studied by electrophoretic analysis of restriction endonuclease fragments. Twenty seven isolates from eight patients in the United Kingdom, obtained before and after treatment with nitrofurantoin, and two reference strains from Australia and Peru were investigated. Digestion of DNA with HaeIII, which gave the clearest band pattern of the 20 enzymes tested, showed that each set of isolates from a single patient had a unique band pattern. The DNA signature band patterns of strains from different patients were less than or equal to 62% similar (average 43%); similarities of patterns from the same patient were generally greater than or equal to 86%. Some minor but reproducible polymorphisms (less than or equal to five bands) in the signature region were detected in most consecutive isolates. Plasmid DNA was detected in isolates from five patients, but major pattern differences were attributed to genomic variation. It is concluded that the HaeIII DNA digest signature fingerprints provide a reproducible and sensitive method of discriminating between isolates of H pylori.

Campylobacter↗
PubMed1990

Cancer risks in painters: study based on the New Zealand Cancer Registry.

Painters are exposed to a range of complex chemical mixtures which include organic solvents and dye products with known carcinogenic and mutagenic potential. Trade painters or those manufacturing paints and coatings have increased rates of non-malignant diseases and cancers; including lung cancer, acute leukaemia, bladder cancer, and cancers of the oesophagus, larynx, biliary system, liver, skin, and large bowel. A series of case-control studies of painters, based on the New Zealand Cancer Registry, are presented. These concerned 19,904 male patients registered for the period 1980-4 who were aged 20 or older at the time of registration. For each cancer site studied, the registrants for all other cancer sites formed the control group. Three cancer sites were associated with work as a painter--namely, bladder tumours (odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.00-2.31), kidney and other urothelial tumours (OR 1.45, 95% CI 0.85-2.50), and multiple myeloma (OR 1.95, 95%, CI 1.05-3.65). Risks for multiple myeloma were greater among car or spray painters and signwriters (OR 2.81) compared with construction and general painters (OR 1.80). No increased risk was found for leukaemia or for respiratory, biliary, skin, or gastrointestinal cancers.

Adult↗
PubMed1989

A New Zealand Cancer Registry-based study of cancer in wood workers.

Wood workers have been previously reported to be at higher risk for the development of cancers of certain sites, including the nasal cavity, paranasal sinuses, lung, stomach, and lymphatic and hemopoietic tissues. Wood work involves exposure to a variety of potential carcinogens, including wood dust itself, chemicals applied to the wood, and other carcinogenic agents that are associated with wood work. We report a series of case-control studies based on the New Zealand Cancer Registry. These studies involved 19,904 male patients registered with cancer from 1980 to 1984 who were 20 years of age or older at the time of registration. For each cancer site studied, the registrants for all other sites (except lung cancer) formed the control group. The following four cancer sites were found to be associated with wood work: lip, nasopharynx, lung, and liver. There was little evidence of increased risks for other cancer sites. Among wood workers, sawmillers experienced the highest risks for lung cancer (odds ratio, 1.76; 95% confidence interval, 1.23 to 2.52) and liver cancer (odds ratio, 3.55; 95% confidence interval, 1.09 to 0.14). Carpenters showed increased risks for lip cancer (odds ratio, 2.28; 95% confidence interval, 1.23 to 4.14) and lung cancer (odds ratio, 1.27; 95% confidence interval, 1.05 to 1.54). The increased risk of nasopharyngeal cancer was strongest for foresters and loggers (odds ratio, 6.02; 95% confidence interval, 1.01 to 28.41).

Adult↗
PubMed1989

Efficacy of a multivalent Bacteroides nodosus vaccine against foot rot in sheep in Britain.

A multivalent Bacteroides nodosus foot rot vaccine was tested by comparing the prevalence of foot rot in 317 vaccinated ewes and lambs with the prevalence in 422 unvaccinated control sheep. The vaccine conferred statistically significant protection against foot rot. The vaccine also demonstrated a therapeutic effect in animals with foot rot, after one injection.

Animals↗
PubMed1989

Soft-tissue sarcoma, non-Hodgkin's lymphoma and other cancers in New Zealand forestry workers.

Several studies have suggested that forestry workers are at increased risk for certain types of cancer including soft-tissue sarcoma (STS) and non-Hodgkin's lymphoma (NHL). We now report a series of national case-control studies based on the New Zealand Cancer Registry (NZCR). These involved 19,904 male patients with cancer for the period 1980-1984 who were aged 20 years or more at the time of registration. For each cancer site, the registrations for the remaining sites formed the control group. Current or most recent occupational titles were coded. There was an increased risk for STS (OR = 3.24) in forestry workers which was confined to men under 60 years of age at registration. An elevation in risk for NHL (OR = 1.84) was due to an increase in risk for lymphosarcoma and reticulosarcoma (ICD 200) (OR = 3.18). Acute myeloid leukemia was also associated with forestry work, although the estimate of risk was imprecise (OR = 2.24). Among other cancer sites, an increase in risk of neoplasia of the upper gastro-intestinal tract (ICD 150, 151, 152) was demonstrated. Odds ratios were elevated for cancer of the esophagus (OR = 1.77), stomach (OR = 2.22), small intestine (OR = 5.22), gall-bladder (OR = 4.13) and pancreas (OR = 1.79), as well as for nasopharyngeal cancer (OR = 5.56). These increases in cancer risk were not present in sawmill workers in New Zealand during the same period. The factors responsible for the increased cancer risks in forestry workers remain unclear and require further study.

Adult↗
PubMed1989

Case-control studies of cancer in New Zealand electrical workers.

A series of reports, including a New Zealand case-control study, have suggested that electrical workers are at increased risk of leukaemia. We report here a further series of case-control studies based on the New Zealand Cancer Registry. These involved 19,904 male patients registered with cancer for the period 1980-1984 who were aged 20 years or more at time of registration. For each cancer site, the registrations for other sites formed the control group. Three main findings emerged. First, there is an elevated leukaemia risk in New Zealand electrical workers (odds ratio (OR) = 1.62, 95% confidence interval (Cl) 1.04-2.52), but little evidence of increased risks for other cancer sites. Second, contrary to other published studies, the increased risk was primarily for chronic leukaemia (OR = 2.12) rather than acute leukaemia (OR = 1.25), and for lymphatic leukaemia (OR = 1.73) rather than myeloid leukaemia (OR = 1.22). Third, the increased risk was strongest for certain categories of electrical work including radio and television repairers (OR = 7.86, 95% CI 2.20-28.09), electricians (OR = 1.68, 95% Cl = 0.75-3.79), linemen (OR = 2.35, 95% Cl 0.97-5.70) and power station operators (OR = 3.89, 95% Cl 1.00-15.22).

Adult↗
PubMed1989

Cancer risks in New Zealand farmers.

Previous New Zealand case-control studies have found increased risk for leukaemia, non-Hodgkin's lymphoma (NHL) and multiple myeloma in farmers. We report here a further series of New Zealand Cancer Registry based case-control studies of farming and site-specific cancer risks. These involved 19,904 males aged 20 years or more who were registered with cancer between 1980 and 1984. For each cancer site, the registrations for other sites formed the control group. Farmers had elevated risks for malignant melanoma (Odds Ratio [OR] = 1.25, 95% confidence interval [Cl] 1.05-1.50), and for cancer of the lip (OR = 2.43, 95% Cl 1.81-3.27), rectum (OR = 1.19, 95% Cl 1.03-1.38), bone (OR = 1.95, 95% Cl 1.00-3.80), prostate (OR = 1.26, 95% Cl 1.13-1.41) and brain (OR = 1.34, 95% Cl 1.04-1.74). Decreased risks were observed for cancer of the larynx (OR = 0.66, 95% Cl 0.45-0.96), lung (OR = 0.70, 95% Cl 0.63-0.77) and testis (OR = 0.58, 95% Cl 0.39-0.88). Livestock farmers had a relatively high risk for brain cancer, while the risk for cancer of the lip was highest among dairy farmers. Farmers also had increased risks for cancer of the lymphatic and haematopoietic system (International Classification of Disease 9th edn (ICD) 200-208) (OR = 1.24, 95% Cl 1.08-1.42), leukaemia (OR = 1.24, 95% Cl 0.99-1.55) and non-Hodgkin's lymphoma (NHL) (OR = 1.24, 95% Cl 0.99-1.56), as described previously.

Adult↗