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Biomedical subjects

R Cumming

Publications and source records attributed to R Cumming.

At least 19 recordsLinked to original sources
PubMed2005

Sexual activity, fertility and contraceptive use in middle-aged and older men: Men in Australia, Telephone Survey (MATeS).

BACKGROUND: With limited information regarding fertility and sexual activity in the older population, men's behaviour, attitudes and concerns were explored in a representative population of middle-aged and older men using the Men in Australia, Telephone Survey (MATeS). METHODS: A stratified random national sample of 5990 men participated in a standardized computer-assisted telephone interview. Equal numbers in the age strata 40-49, 50-59, 60-69 and >or=70 years were surveyed with findings census-standardized to the national population. Broad aspects of men's health and well-being, including reproductive health, were explored. RESULTS: The majority of men were sexually active in the last 12 months (age-standardized proportion, 78.3%) with approximately 37% of men aged >or=70 years still continuing sexual activity. Overall, 12.2% of men had never fathered children, of whom most (7.7%) had chosen not to have children. Questioning on failed attempts to produce a pregnancy suggested an involuntary infertility rate of 7.6%. The age-standardized vasectomy rate was 25.1%, with 5.6% of vasectomized men having no children. Although 9.2% of vasectomized men regretted sterilization, only 1.4% had undergone vasectomy reversal. CONCLUSIONS: Continuing sexual activity, fertility and contraception needs in middle-aged and older men suggests that education and service delivery must be more appropriately directed to an ageing population.

Adult↗
PubMed2004

The effects of age, death period and birth cohort on asthma mortality rates in Australia.

SETTING AND OBJECTIVE: We assessed the relative effects of age, gender, period of death and birth cohort on asthma mortality rates in Australia from 1907 to 2000. DESIGN: Asthma mortality data obtained from the Australian Institute of Health and Welfare were adjusted for changes to the International Classification of Diseases and examined for changes over time and age, period and cohort effects. RESULTS: Age-adjusted period asthma mortality rates indicated epidemics during the mid 1960s and 1980s, predominantly affecting those aged 5-34 years. The main 1960s epidemic coincided with the introduction of high-dose, non-selective beta-sympathomimetic amines. There was a gradual rise in mortality rates in younger age groups, with rates rising from 0.5/100 000 males and 0.9/100 000 females in the 1940s to a peak of 3/100 000 for both sexes in 1966. Fluctuations in mortality rates were influenced by period of death and birth cohort. There was an increased risk of death from asthma with increasing age. CONCLUSION: There was no overall trend in asthma mortality rates in any age group. The 1960s epidemic was probably treatment related. Other increases in mortality occurring despite therapeutic advances may reflect increasing prevalence and highlight the need for ongoing surveillance.

Adolescent↗
PubMed2001

Passive smoking and lung cancer: a cumulative meta-analysis.

OBJECTIVE: To review the epidemiological evidence for the association between passive smoking and lung cancer. METHOD: Primary studies and meta-analyses examining the relationship between passive smoking and lung cancer were identified through a computerised literature search of Medline and Embase, secondary references, and experts in the field of passive smoking. Primary studies meeting the inclusion criteria were meta-analysed. RESULTS: From 1981 to the end of 1999 there have been 76 primary epidemiological studies of passive smoking and lung cancer, and 20 meta-analyses. There were 43 primary studies that met the inclusion criteria for this meta-analysis; more studies than previous assessments. The pooled relative risk (RR) for never-smoking women exposed to environmental tobacco smoke (ETS) from spouses, compared with unexposed never-smoking women was 1.29 (95% CI 1.17-1.43). Sequential cumulative meta-analysed results for each year from 1981 were calculated: since 1992 the RR has been greater than 1.25. For Western industrialised countries the RR for never-smoking women exposed to ETS compared with unexposed never-smoking women, was 1.21 (95% CI 1.10-1.33). Previously published international spousal meta-analyses have all produced statistically significant RRs greater than 1.17. CONCLUSIONS: The abundance of evidence in this paper, and the consistency of findings across domestic and workplace primary studies, dosimetric extrapolations and meta-analyses, clearly indicates that non-smokers exposed to ETS are at increased risk of lung cancer. IMPLICATIONS: The recommended public health policy is for a total ban on smoking in enclosed public places and work sites.

Developed Countries↗
PubMed2000

Interventions for preventing falls in the elderly.

BACKGROUND: Fractures in the elderly often result from a simple fall. OBJECTIVES: To assess the effects of programmes designed to reduce the incidence of falls in community dwelling, institutionalised, or hospitalised elderly people. SEARCH STRATEGY: We searched MEDLINE, EMBASE, CINAHL, PsycLIT, Social Science Citation Index, Dissertation Abstracts, Index to UK Theses, the Cochrane Register of Controlled Trials, and bibliographies of identified studies. We contacted known workers in the field. Trials were also obtained from the Cochrane Musculoskeletal Injuries Group trials register. Date of the most recent search: May 1997. SELECTION CRITERIA: Randomised trials of interventions designed to minimise the effect of, or prevent exposure to, any putative risk factor for falling in elderly individuals living in the community, in institutional care, or in hospital. The main outcomes of interest were number of fallers or falls, or the number sustaining a fall resulting in injury. Trials that focused on intermediate outcomes such as improved balance or did not report fall outcomes, were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers selected trials for inclusion. For each included trial, quality assessment and data extraction was carried out independently by two reviewers. Results of trials of similar design were pooled. MAIN RESULTS: Eighteen trials and one pre-planned meta-analysis were included. The analysis of four trials which studied the effect of exercise alone did not establish protection against falling (Peto odds ratio 1.05; 95% confidence interval 0.74 to 1.48). Based on one trial, there was no evidence to support exercise in conjunction with health education classes (Peto odds ratio 1.72; 95% confidence interval 0.78 to 3.75), or of health education classes alone (Peto odds ratio 1.25; 95% confidence interval 0.51 to 3.03) for the prevention of falls. However, significant protection against falling was apparent from interventions which targeted multiple, identified, risk factors in individual patients (Peto odds ratio 0.77; 95% confidence interval 0. 64 to 0.91), and from interventions which focused on behavioural interventions targeting environmental hazards plus other risk factors (Peto odds ratio 0.81; 95% confidence interval 0.71 to 0.93). REVIEWER'S CONCLUSIONS: Health care purchasers and providers contemplating fall prevention programmes should consider health screening of at risk elderly people, followed by interventions which are targeted at both intrinsic and environmental risk factors of individual patients. There is inadequate evidence for the effectiveness of single interventions such as exercise alone or health education classes for the prevention of falls.

Accidental Falls↗
PubMed1998

Prevalence and causes of amblyopia in an adult population.

OBJECTIVE: The study aimed to determine the prevalence, causes, and associations with amblyopia in a defined older population. DESIGN: In a population-based study, 3654 persons 49 years of age or older from an area west of Sydney, Australia, underwent a detailed eye examination and history, including objective and subjective refraction, cover testing, and retinal and lens photography. Amblyopia was diagnosed in eyes with reduced best-corrected visual acuity in the absence of any other cause. RESULTS: Amblyopia was diagnosed in 118 participants, or 3.2% of the population using a visual acuity criterion of 20/30 or less and 2.9% using a visual acuity criterion of 20/40 or less. Using a two-line visual acuity difference between the eyes, the amblyopia prevalence was 2.6% and 2.5%, respectively, for the above criteria. The underlying amblyogenic causes assessed were anisometropia (50%), strabismus (19%), mixed strabismus and anisometropia (27%), and visual deprivation (4%). The visual acuity of the amblyopic eye was 20/200 or worse (19%), 20/80 to 20/160 (19%), 20/40 to 20/63 (52%), and 20/30 (11%). No statistically significant associations were found between amblyopia and gender or eye affected. The most frequent pattern of strabismus was esotropia, whereas hypermetropia was the most frequent refractive error in amblyopic eyes. The mean age at diagnosis was earlier for strabismic and mixed amblyopia (7.4 years) than for anisometropic amblyopia (12.7 years). CONCLUSION: This study has provided prevalence and cases of amblyopia in an older population. Amblyopia is a frequent cause of lifelong unilateral visual impairment.

Aged↗
PubMed1997

Toxicity assessment of xenobiotic contaminated groundwater using lux modified Pseudomonas fluorescens.

A bacterial bioassay, suitable for rapid screening to assess the relative toxicity of xenobiotic contaminated groundwater has been developed. The quantitative bioassay utilizes a decline in luminescence of the lux marked soil bacterium Pseudomonas fluorescens on exposure to contaminated groundwaters from which effective concentration (EC) values can be assessed and compared. P. fluorescens was most sensitive to semivolatile organics in groundwaters but there was no correlation between EC value and chemical content. The sensitivity and reproducibility of the P. fluorescens bioassay was compared with that of Microtox and results showed that mean EC50 values for diluted ground water replicate samples were 20% and 18% respectively. This suggested that the P. fluorescens bioassay was as applicable to groundwater screening as the widely used Microtox bioassay.

Benzene↗
PubMed1997

Knowledge and beliefs about common eye diseases.

PURPOSE: To ascertain the level of knowledge of common causes of blindness in an adult Australian population and to relate this to use of eye care services. METHODS: A population-based study of common eye diseases in an urban population aged 49 years or older was conducted. The questions were concerned with the awareness and knowledge of and the ability to describe three common eye diseases, namely cataract, glaucoma and age-related macular degeneration (AMD). RESULTS: Awareness of cataract (98%) and glaucoma (93%) were high in this population, but awareness of AMD was low (20%). Among people who were aware of the target eye disease, only 29% showed some knowledge of glaucoma, 26% showed some knowledge of AMD and 20% showed some knowledge of cataract; this was also low in people who had previous eye treatment, such as cataract surgery. Knowledge was related to education level, occupational prestige and knowledge of other eye diseases. After excluding people with a previous eye disease diagnosis, those people who were aware and had some knowledge of eye disease accessed eyecare services more frequently. CONCLUSIONS: Knowledge of common eye diseases is generally lacking. Age-related macular degeneration is the leading cause of blindness in Australia, yet only 20% of the present study population had heard of it. As there are often no early symptoms for glaucoma, community awareness of this disease and the need for screening of people at risk may allow timely diagnosis and more effective therapy before advanced visual field loss has occurred. An informed public is more likely to present earlier with visual symptoms before irreversible visual loss has occurred and is more likely to comply better with recommended therapy.

Adult↗
PubMed1992

Crown of microfilaments in the extending cytoplasmic processes of medulloblastoma glial progenitors.

Microfilaments and microtubules play a part in the extension of neuronal processes but their roles in the formation of glial processes have not yet been determined. The objectives of this study were to determine the organization of microfilaments in differentiating glial progenitors (RB2 cells) and to study the effects of microfilament or microtubule disruption on process extension. Intense F-actin staining (crown of microfilaments) was observed at the leading edge of a small extending conical tip in differentiating RB2 cells, but was absent in process-bearing TE671 rhabdomyosarcoma cells. No significant difference was noted in the mean number of TE671 cells with processes treated with a microfilament disrupter from that of similarly treated controls. In contrast, a significant difference was noted in the mean number of RB2 cells with processes after microfilament disruption treatment from that of similarly treated controls. Microtubule disruption arrested extension and caused process retraction in both cell types. The results of this study demonstrate that microtubules play an equally important part in the extension and stabilization of the RB2 and TE671 processes. Moreover, the crown of microfilaments concentrated in the glial RB2 process (and not in the TE671 process) may be critical to its extension during differentiation.

Actin Cytoskeleton↗
PubMed1991

Cardiovascular implant calcification: a survey and update.

Calcification of cardiovascular prosthetic implants is a common and important problem. This review provides an update based upon the Conference on Cardiovascular Implant Calcification held as part of the 13th World Congress of the International Society for Heart Research, 1989. A variety of cardiovascular prostheses are affected clinically by calcification, including bioprosthetic heart valves, aortic homografts and trileaflet polymeric valve prostheses. In addition, experimental studies have demonstrated calcification of artificial heart devices in ventricular assist systems in long-term calf studies. The pathophysiology of this disease process is incompletely understood. A common element between the various types of cardiovascular implant calcification is the localization of calcific deposits to devitalized cells and membranous debris. Prevention of cardiovascular implant calcification by either biomaterial modifications or regional drug therapy (controlled release) is being investigated.

Animals↗
PubMed1990

Enhanced chemiluminescence for tissue antigen and cellular viral DNA detection.

The ability to use enhanced chemiluminescence (ECL) to detect horseradish peroxidase as a label for tissue antigens and cellular viral DNA was demonstrated. A liquid nitrogen-cooled charged-coupled device (CCD) was used to detect light output, which was visualized on a monitor or was quantitated using an attached microcomputer. In a tissue antigen model, equivalent sensitivity was observed between ECL and colorimetric detection.

Antigens, Neoplasm↗
PubMed1984

Immunofluorescence distribution of alpha tubulin, beta tubulin and microtubule-associated protein 2 during in vitro maturation of cerebellar granule cell neurones.

In vivo developmental immunocytochemical studies have recently shown that granule cell axons (parallel fibres) undergo progressive modification of alpha tubulin as they form permanent synapses, a change that is not observed in other microtubule-containing structures (e.g. Purkinje cell dendrites). In this study we have used primary cultures of young rat cerebellum enriched in granule cells to follow maturation of their axons under defined in vitro conditions. Our results show that alpha tubulin is not modified in culture as assessed by immunofluorescence using monoclonal antibodies that recognise different forms of alpha tubulin. We have also confirmed in vivo data showing that microtubule-associated protein 2 is absent from granule cell axons at all developmental stages in vitro. The distribution of axonal cytoskeletal proteins is compared and contrasted during in vivo and in vitro maturation, and considered in relation to differences between the two systems.

Animals↗
PubMed1984

Ontogeny of microtubule-associated protein 2 in rat cerebellum: differential expression of the doublet polypeptides.

We have examined the ontogeny of the microtubule-associated protein, MAP2 in rat cerebellum using biochemical and immunocytochemical techniques. In adult animals MAP2 can be resolved as a doublet of polypeptides (referred to here as MAP2a and MAP2b). In young rats only the lower molecular weight MAP2b was present in cerebellar cytosol; MAP2a appeared by 20 days postnatally. The identification of the polypeptides as MAP2a and MAP2b in heat-stable fractions of cytosol was confirmed by peptide mapping which also demonstrated that MAP2a and MAP2b shared virtually identical peptide maps. Using a rabbit anti-MAP2 antibody that was characterised by immunoblotting of cerebellar homogenates, the localisation of MAP2 was examined in 10-day-old and adult cerebella. In 10-day-old animals, MAP2 immunoreactivity was detected in the external germinal layer, granular layer and most strikingly in Purkinje cell bodies and dendrites. Parallel fibre axons were unstained. In contrast both axons and dendrites were stained by an antibody against alpha-tubulin. In adult animals MAP2 immunoreactivity was largely confined to Purkinje cell dendrites. The absence of assembled microtubules from Purkinje cell dendrites of young animals despite the presence of MAP2 and tubulin immunoreactivity may be explained by the presence of only a single MAP2 polypeptide (MAP2b) whereas the presence of the MAP2 doublet polypeptides in the adult may facilitate polymerization. Since MAP2b does not co-assemble with microtubules efficiently in vitro it may represent a form of MAP2 unable to stimulate microtubule assembly. Therefore, the possibility exists that MAP2b may play an alternative role during dendritic growth.

Aging↗
PubMed1984

Immunocytochemical demonstration of alpha-tubulin modification during axonal maturation in the cerebellar cortex.

Previous light microscopic immunocytochemical studies using two monoclonal antibodies that recognise alpha-tubulin (YOL/34 and YL1/2) but differ in their isotypic specificity have shown that the unmyelinated parallel fiber axons in the cerebellar cortex are labeled with only one of the antibodies (YOL/34). We now show that at 10 d postnatally the parallel fibers are labeled with both antibodies, and that during development YL1/2 (but not YOL/34) immunoreactivity disappears progressively from parallel fibers in the lower regions of the molecular layer upwards towards the external germinal layer. By approximately 28 d postnatally, the differential staining pattern of parallel fibers by the antibodies is established throughout the molecular layer. The time course, light microscopic, and ultrastructural staining distribution corresponds to a progressive change in alpha-tubulin immunoreactivity as the parallel fibers form synaptic contacts. This modification of alpha-tubulin (which was not observed in Purkinje cell dendrites or Bergmann glia) may be related to the formation of a basic isotype of alpha-tubulin within parallel fiber axons at maturation.

Animals↗
PubMed1983

Taxol stabilizes synaptosomal microtubules without inhibiting acetylcholine release.

Synaptosomes assemble an equatorial coil of microtubules during incubation at 37 degrees C. Stimulation of synaptosomes by veratridine or A23187 for 5 min results in disassembly of the microtubules. The role of microtubule disassembly in neurotransmitter release was investigated using the microtubule-stabilizing drug taxol. Taxol stimulates microtubule assembly in synaptosomes and prevents microtubule disassembly caused by A23187. However, taxol has no effect on the release of [3H]acetylcholine triggered by veratridine or A23187. These results suggest that microtubule turnover is not necessary for neurotransmitter release.

Acetylcholine↗
PubMed1983

Immunocytochemical evidence for tubulin in the presynaptic terminal of synaptosomes.

Ultrastructural studies of intact tissue rarely show presynaptic microtubules, and immunocytochemical studies on tissue sections have previously been unable to demonstrate tubulin in the nerve terminal. In contrast, a microtubular coil can be readily detected in the presynaptic nerve terminal of synaptosomes. We have developed an immunocytochemical procedure on the synaptosome preparation and demonstrated, using monoclonal antibodies, that in the presynaptic terminal alpha and beta tubulin subunits are specifically restricted to the equatorial microtubular coil.

Animals↗