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Biomedical subjects

C Kerr

Publications and source records attributed to C Kerr.

At least 37 records · Page 2Linked to original sources
PubMed1998

Best estimate of the magnitude of mortality due to occupational exposure to hazardous substances.

OBJECTIVES: With a proportionate attributable risk approach, to estimate the magnitude of premature mortality induced by exposure to hazardous substances in the Australian workforce. METHODS: Estimates of the magnitude of mortality induced by exposure to hazardous substances in the Australian work-force were calculated by the proportionate attributable risk approach after careful consideration of options for methodological refinements. The main data sources used were unit mortality datasets (individual deidentified death records), and tabulations when these were unavailable. RESULTS: The estimated number of deaths that occurred in Australia each year from occupational exposure to hazardous substances was 2290; 78% of these were men. The rate of mortality attributable to occupational exposure to hazardous substances was three to four times greater in male workers than in female workers. Male (productive) person-years of life lost (PYLL) were generally eight times higher than female PYLL. Cancer was the prime cause of death, followed by renal, cardiovascular, neurological, and chronic respiratory disease. Acute toxic episodes accounted for a small proportion of mortality but yielded a much larger proportion of PYLL, reflecting the relatively young ages of those who experienced fatal effects. CONCLUSIONS: Although national estimates of the proportions of mortality attributable to occupational exposure to hazardous substances seemed to be validly derived, uncertainties remain associated with the lack of an empirical basis for derivation of proportionate risk fractions used in the calculations. The finding of an appreciable burden of mortality that is attributable to past occupational exposure to hazardous substances emphasises the necessity for occupational health and safety authorities to measure and reduce worksite exposures. There is also an incentive to encourage the construction of appropriately designed cohort studies across industries and occupational groupings so that, ultimately, risk estimates may be directly calculated and applied to total workforce data for the definitive estimation of the magnitude of harm induced by occupational exposure to hazardous substances.

Australia↗
PubMed1998

The relationship between dental disease and cerebral vascular accident in elderly United States veterans.

We report here information obtained from a cross-sectional study of 401 veterans, who were at least 60 years of age, which showed that several dental/oral conditions can be significantly associated with the diagnosis of a cerebral vascular accident (CVA), when included in a multivariate logistic regression model with and without many of the known risk factors for a CVA. The dental findings relative to the prevalence of dental caries and periodontal disease were not distinctly different between the subjects with and without a CVA in the bivariate analysis. A higher stimulated salivary flow was negatively associated with a CVA in the multivariate models. The plaque index and oral hygiene habits relating to brushing, flossing, and frequency of having teeth cleaned by a dentist/hygienist were significantly associated with a CVA in the bivariate analysis. Among these oral hygiene parameters, *needing help in brushing one's teeth" and the reported annual visit to the dentist/hygienist for teeth cleaning remained significant in the multivariate models involving the dependent-living subjects. The need for help in brushing one's teeth could reflect the fact that many subjects had reduced manual dexterity as a result of the CVA and required this extra care. However, the finding that those dependent-living individuals who reported that they did not have their teeth cleaned at least once a year were 4.76 times more likely to have had a CVA, suggests that a pattern of oral neglect might be associated with developing a CVA. The implications of this in terms of an intervention strategy for CVA warrants further consideration. However, caution is recommended because the data were obtained from a convenience sampling of older veterans and may not be generalizable to other populations.

Aged↗
PubMed1997

Regulation of tissue inhibitor of metalloproteinase-1 in fibroblasts and acute phase proteins in hepatocytes in vitro by mouse oncostatin M, cardiotrophin-1, and IL-6.

Mouse oncostatin M (mOSM) has been recently cloned; however, its full spectrum of biologic functions has not been defined. To assess its potential role in inflammation, we have tested the activity of mOSM in vitro in regulation of fibroblasts and hepatic cells. At concentrations of 10 and 20 ng/ml, mOSM stimulates tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA in NIH-3T3 mouse embryonic fibroblasts, rat lung fibroblasts, and rat synovial fibroblasts, whereas mouse cardiotrophin-1 (mCT-1) or human OSM (hOSM) did not. Similarly, only mOSM was able to induce transcription of chloramphenicol acetyl-transferase (CAT) in NIH-3T3 cells transfected with a minimal TIMP-1 promoter/CAT construct. Mouse OSM had strong action inducing primary rat hepatocyte cultures to produce acute phase proteins; however, mOSM was very weak in its ability to stimulate acute phase protein synthesis in rat H35 cells or human HepG2 cells, which was consistent with weak STAT activation in H35 cells and HepG2 cells. Binding studies showed that NIH-3T3 cells possessed high affinity binding sites for mOSM, but rat H35 cells did not. On the other hand, mCT-1 and mouse IL-6 induced strong STAT activation as well as marked increases in acute phase protein production by H35 cells. These results indicate that mOSM does not share a functional receptor with mCT-1 or hOSM in mouse and rat cells and that hOSM does not activate the putatively specific OSM receptor on mouse or rat cells. These results also suggest that mOSM is an important cytokine in inflammation, through modulation of fibroblast function as well as hepatocyte responses.

3T3 Cells↗
PubMed1997

Association of tyrosine-phosphorylated c-Src with the cytoskeleton of hypertrophying myocardium.

Given the central position of the focal adhesion complex, both physically in coupling integrins to the interstitium and biochemically in providing an upstream site for anabolic signal generation, we asked whether the recruitment of non-receptor tyrosine kinases to the cytoskeleton might be a mechanism whereby cellular loading could activate growth regulatory signals responsible for cardiac hypertrophy. Analysis revealed cytoskeletal association of c-Src, FAK, and beta3-integrin, but no Fyn, in the pressure-overloaded right ventricle. This association was seen as early as 4 h after right ventricular pressure overloading, increased through 48 h, and reverted to normal in 1 week. Cytoskeletal binding of non-receptor tyrosine kinases was synchronous with tyrosine phosphorylation of several cytoskeletal proteins, including c-Src. Examination of cytoskeleton-bound c-Src revealed that a significant portion of the tyrosine phosphorylation was not at the Tyr-527 site and therefore presumably was at the Tyr-416 site. Thus, these studies strongly suggest that non-receptor tyrosine kinases, in particular c-Src, may play a critical role in hypertrophic growth regulation by their association with cytoskeletal structures, possibly via load activation of integrin-mediated signaling.

Animals↗
PubMed1997

Icebox, a recessive X-linked mutation in Drosophila causing low sexual receptivity.

The X-linked recessive mutation icebox (ibx; 1-23, 7F1) of Drosophila melanogaster lowers the sexual receptivity of females. The probability of mating with mature wild-type males is reduced in ibx homozygotes, and the frequency of rejection behavior (rate per minute) towards courting males is increased. ibx fails to complement In(1)RA35, which is a lethal allele of Neuroglian (Nrg, which encodes a transmembrane protein found in embryonic tissues including the nervous system) due to a breakpoint in that gene; however, both l(1)B4 and l(1)VA142, other lethal mutations of Nrg, do complement ibx. 12-h ibx embryos exhibit a normal pattern of staining for the Neuroglian-specific antibody, Mab BP104. Males and females mutant for ibx have normal egg-to-adult survival and appear normal in several "general" behavioral traits including olfaction, phototaxis, locomotor activity, and heartbeat. ibx males court normally, and are successful in mating. These characteristics suggest that ibx does not cause sensory or motor defects. Ovarian growth and sperm storage are wild-type in ibx/ibx females. Treatment with the JH analog methoprene increases the receptivity of ibx/ibx females.

Animals↗
PubMed1997

A review of school vision screening in Glasgow.

OBJECTIVES: To assess to what extent the primary school vision screening programme was being carried out in the years 1993-94 and 1994-95, what the prevalence of eye defects was in the primary schools and how many children had a positive screening test. DESIGN: Summary sheets of the results of screening were returned by each school nurse. SETTING: All 315 mainstream primary schools served by Greater Glasgow Health Board. SUBJECTS: All school nurses working in these schools. RESULTS: Large numbers of tests were being performed but the screening programme was not fully carried out in 10% of schools in 1993-94 and in 68% in 1994-95, although the number of schools where some screening was performed did increase. The years were not directly comparable due to a change in the age groups screened. When a class was screened 94-96% of children were tested. The rate of positive screening varied from 4% to 15.6% and varied with age and locality. Fewer abnormalities were found at five years than in the older age groups (Primary 1-7.6%, Primary 4-11.4%, and Primary 7-9.7%) and fewer abnormalities were detected in the North-West area where a pre-school orthoptic screening programme was operating (4% in the North-West compared with 11% in the South where no pre-school screening was carried out). CONCLUSION: If the recommended programme is carried out, then 95% of children at age five years could be tested at a stage when amblyopia is still potentially treatable. The reasons for the programme not being completed require to be addressed. Variations between areas need to be confirmed and the reasons for them identified. Further evaluation of the programme is required, exploring the accuracy of it and the long-term outcomes.

Child↗
PubMed1996

Follow-up of atrial fibrillation: The initial experience of the Canadian Registry of Atrial Fibrillation.

Previous reports of the follow-up of patients with atrial fibrillation have been confusing because of the variety of clinical presentations, heterogeneity of underlying pathology, and the initiation of follow-up at various stages of the patient's disease. The Canadian Registry of Atrial Fibrillation (CARAF) is a non-interventional, follow-up study of patients enrolled at the time of their initial diagnosis with atrial fibrillation at seven Canadian centres. At baseline, a comprehensive database recorded clinical, laboratory, and echocardiographic variables. No specific intervention was initiated and care was left to the attending physicians. Follow-up was performed at 3 months, 1 year, then annually. Echocardiograms were repeated every 2 years. Recurrence of atrial fibrillation, medical intervention, stroke, death, and other significant events have been specifically recorded. To date, 967 patients have been enrolled. Seven hundred and sixty-seven patients have been followed for 1 year, 468 for 2 years, and 217 for 3 years. Several studies have been undertaken on these patients. One study compared the variables of patients who were symptomatic with those who were asymptomatic. This study demonstrated that symptoms were more likely to occur if the patient were younger, had high blood pressure and high ventricular response during atrial fibrillation, and were female. These all achieve statistical significance and a formula was developed to predict the probability of symptoms in different subgroups of patients. Antiarrhythmic drug use was evaluated. Sotalol and propafenone were the most commonly used drugs and their use increased when atrial fibrillation was recurrent. Many patients initially received no antiarrhythmic drugs. Trends suggest that therapy is more aggressive with recurrence of the arrhythmia. The prevalence of thyroid abnormalities was investigated utilizing sensitive TSH measurements. This showed that overt hyperthyroidism is rare (1%) but laboratory abnormalities and history of thyroid dysfunction occurred more frequently, in 19% of patients. Another study evaluated antithrombotic therapy. Factors known to increase stroke risk, including congestive heart failure, previous stroke, and large left atrium all increased the use of anticoagulants. Anticoagulants were used more frequently in patients over the age of 65 and in patients with recurrent or chronic atrial fibrillation. There was concern that hypertension, shown to be a high predictor of stroke, did not result in a significant use of warfarin. Aspirin use was common in patients not placed on anticoagulants. Further studies are being undertaken with the ultimate goal to utilize baseline data to predict clinical outcomes.

Anti-Arrhythmia Agents↗
PubMed1995

A simple geriatric assessment measure to assist a consultative team decision for nursing home placement.

In this study, Barthel and Mini-mental State Examination scores were combined and examined for their ability to predict a geriatric assessment team's decisions for nursing home care. We examined cross-sectional data from a project of consultative geriatric assessment for nursing home applicants in a high socioeconomic status area of Sydney, Australia. The maximum combined score was 160, and a "grey zone" between 100 and 140 was identified where classification errors were greater than 30%. Above 140, most patients were assigned by the team to other care, and below 100, nursing home care was recommended for most. The effectiveness of a classification test will be increased by identification of a grey zone so that if patients fall within this zone, greater care can be taken in the decision-making process. Given the select nature of subjects in this analysis, the generalizability of the derived combined score will be limited. However, the study illustrates one approach that may be taken in the development of classification methods to aid decision-making in the clinical or screening settings.

Geriatric Assessment↗
PubMed1995

Aborigines and tuberculosis: why they are at risk.

Aborigines have higher rates of Mycobacterium tuberculosis than the rest of the community. There are insufficient contemporary data to assess how much risk tuberculosis poses to the Aboriginal community. Tuberculosis is of particular concern because of its interaction with human immuno-deficiency virus (HIV). We aimed to ascertain the available data about tuberculosis in Australian Aborigines: to determine morbidity and mortality of tuberculosis in Australian Aborigines, to ascertain the extent of known risk factors for tuberculosis in Australian Aborigines and to consider the public health implications of our findings. Sparse evidence suggests that Aborigines have higher rates of infection and of clinical tuberculosis than non-Aboriginal Australians, along with a high prevalence of known risk factors for tuberculosis. However, there is a paucity of data about specific risk factors and tuberculosis in Aborigines. In addition, Aborigines have a high prevalence of risk factors for HIV infection. The existence of concurrent risk factors for tuberculosis and HIV, in a population that already has a high rate of infection with tuberculosis is cause for grave concern. Tuberculosis control is centred on correct and rapid diagnosis and appropriate treatment, as well as efficient contact tracing. These are the most important strategies for control of tuberculosis among Aborigines, and are especially important when there is concurrence of other risk factors. Appropriate preventive therapy for infected people should also be considered.

Australia↗
PubMed1995

Acoustic neuroma standard of care.

Patients who have undergone acoustic neuroma surgery require expert, comprehensive nursing care. This article includes a standard of care and tables about neurological assessment, potential complications, home safety and discharge instructions. A holistic, multidisciplinary approach can enable nurses to promote the recovery of acoustic neuroma patients and ultimately improve their outcomes.

Humans↗
PubMed1994

Multivariate analysis of prognostic factors in adult patients with medulloblastoma. Retrospective study of 156 patients.

BACKGROUND: Medulloblastoma is a rare disease in adult patients, with an annual incidence rate of 0.05 per 100,000 per year. Results are, therefore, sparse and comprise small series over long periods. The real survival rate, the prognostic factors, the optimal postoperative radiation dose, and the role of adjuvant chemotherapy are still unknown for this disease in adults. METHODS: The authors collected 156 cases of histologically proven medulloblastoma in patients older than 18 years of age who were treated between January 1975 and December 1991 in 13 French institutions. They analyzed the prognostic factors for survival and the impact of postoperative treatment on survival. RESULTS: The 5- and 10-year event free survival rates, 61 and 48%, respectively, are similar to those observed in children. The median time to recurrence is 30 months, but late relapses after 5 years remain frequent. Multivariate analysis identified postoperative performance status, spinal axis radiation dose, fourth ventricular floor involvement, and desmoplastic histologic subtype as factors significantly correlated with event free survival. No benefit of concomitant chemotherapy was demonstrated, and complete resection resulted only in severely reduced postoperative performance status. CONCLUSIONS: The prognostic factors in adult medulloblastoma are comparable to those of medulloblastoma in children, but a new parameter, postoperative performance status, was identified in this adult series. Postoperative craniospinal irradiation remains the standard treatment for adults with medulloblastoma. A reduced dose to the supratentorial compartment should be tested in a prospective protocol.

Adult↗
PubMed1994

A cohort study of unemployment as a cause of psychological disturbance in Australian youth.

Data from the Australian Longitudinal Survey, conducted by the Commonwealth Department of Employment, Education and Training, were analysed to estimate relative risk of psychological disturbance accompanying unemployment in young people aged 15-24 years. Two cohorts were surveyed annually over 4 years during the mid-to-late-1980s; one from the general 15-24 year-old population (N = 8995), and the other selected from Commonwealth Employment Service records (N = 2403). Such large respondent numbers allowed control of confounding by exclusion to isolate employment transition groups suitable for hypothesis testing and quantification of causal relationships. Psychological morbidity was measured using binary outcomes of the 12 item psychological component of the General Health Questionnaire. Excluded from the analysis were those who: suffered from pre-existing physical health problems; were dissatisfied in their job; were self-employed; underwent marriage breakdown during the inter-survey period; had become widowed during the inter-survey period. A Bayesian probabilistic approach was used to calculate probabilities of psychologically normal respondents becoming psychologically morbid, given prior transition from employment to unemployment. Mantel-Haenszel analysis was utilised to estimate relative risks in comparison to a control group of those remaining employed, after controlling for age and gender. An overall relative risk of becoming psychologically disturbed as a consequence of becoming unemployed was estimated to be 1.51 (95% CI: 1.15-1.99). The overall relative risk of recovery from psychological disturbance upon re-employment in those with psychological disturbance was estimated to be 1.63 (95% CI: 1.08-2.48). Residual psychological effects of past unemployment experience and the effects of long-term unemployment were investigated, but found to be non-significant in this study. There was some evidence of psychological adaptation to unemployment, but this was statistically insignificant. Unemployment was a significant cause of psychological disturbance in young people who were initially employed, not suffering physical ill-health, and psychologically normal; conversely, re-employment reversed the effect.

Adaptation, Psychological↗