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Biomedical subjects

J Mitchell

Publications and source records attributed to J Mitchell.

At least 73 records · Page 4Linked to original sources
PubMed2001

Low faecal elastase 1 concentrations in type 2 diabetes mellitus.

BACKGROUND: Previous studies have suggested an association between impaired pancreatic exocrine function and diabetes, but the evidence is weak because the invasive nature of the tests used to define exocrine function has led to small studies on selected patients. The availability of faecal elastase 1 as a non-invasive test has aided the detection of impaired exocrine function in population studies. We describe the association between levels of faecal elastase 1 and Type 2 diabetes. METHODS: 544 Type 2 diabetic patients (age: 63 +/- 8 years) were randomly selected from local diabetes registers in Cambridgeshire, UK and individually matched for age, sex and practice to 544 controls in whom diabetes was excluded by HbA1c measurement. RESULTS: Faecal elastase 1 concentrations were significantly lower in cases than controls (median: cases 308 microg/g; controls 418 microg/g; P < 0.01). Low levels of faecal elastase 1 (< 100 microg/g) were found in 11.9% of cases and 3.7% of controls (age-sex-adjusted odds ratio; 95% CI: 3.6; 2.2-6.2). After adjustment for potential confounding factors, the OR was 4.5 (2.6-8.3). Among patients with diabetes, poor glycaemic control (HbA1c > or = 7%) was associated with a higher risk of low elastase 1 level (OR 5.6; 1.5-37). No significant association was found with diabetes duration, peripheral neuropathy, alcohol intake, or prior gastrointestinal diseases. CONCLUSIONS: Faecal elastase 1 concentrations are lower in Type 2 diabetic patients than in non-diabetic controls, suggesting the co-existence of diabetes and impaired pancreatic exocrine function. Among the diabetic patients, the risk of having low elastase 1 levels was associated with glycaemic control.

Aged↗
PubMed2001

Mismanaging prescription medications among rural elders: the effects of socioeconomic status, health status, and medication profile indicators.

PURPOSE: This study assessed the extent to which community-dwelling rural older adults mismanage their prescription medication regimens and predicted mismanagement of medications from selected socioeconomic, health status, and medication profile characteristics. DESIGN AND METHODS: Personal interviews with 499 community-dwelling adults aged 66 and over taking at least one prescription medication and living in a rural region of the Southeast. With approximately equal numbers of African American and white men and women, the SUDAAN multiple logistic regression procedure was used to predict the mismanagement of prescription medications. RESULTS: The mismanagement of prescribed medication regimens is relatively common among older adults. Those more likely than others to mismanage their regimens are African American, younger, in poorer mental health, with more acute care physician visits, and those who find payment for their medications to be problematic. IMPLICATIONS: The implications of the findings for what is known about the self-modification of drug regimens, targeting prescription drug cost benefits or interventions, and the limitations of the study are discussed.

Black or African American↗
PubMed2001

Estimating energy expenditure by heart-rate monitoring without individual calibration.

UNLABELLED: Heart rate monitoring has been shown to be a valid method for measuring free-living energy expenditure at the group level, but its use in large-scale studies is limited by the need for an individual calibration of the relationship between heart rate and energy expenditure. PURPOSE: To determine whether energy expenditure can be estimated from heart rate monitoring without individual calibration in epidemiological studies. METHODS: Our previously validated heart rate monitoring method relies on measuring individual calibration parameters obtained from resting energy expenditure and the regression line between energy expenditure and heart rate during exercise. We developed prediction equations for these parameters using easily measured variables in a population-based study of 789 individuals. The predictive ability of these parameters was tested in a separate population-based sample (N = 97). RESULTS: Physical activity level (PAL = total energy expenditure/basal metabolic rate) using the four estimated parameters was correlated with PAL using the measured parameters (r = 0.82, P < 0.01). Comparison of measured and estimated PAL showed that 97.9% of the scores were placed in the same or adjacent quartile. CONCLUSION: A combination of simple measurements and heart rate monitoring produces estimates of energy expenditure that are highly correlated with those obtained using full individual calibration. This simplification of the heart rate monitoring method could extend its use in ranking individuals in epidemiological studies.

Calibration↗
PubMed2001

Re-framing risk: the changing context of disaster mitigation and preparedness.

This issue of Disasters explores the roles of NGOs and other actors in disaster mitigation and preparedness and also reviews broad international trends in risk management and disaster prevention. The need to address risk, and with that the motivation to improve disaster mitigation and preparedness, has tended to fall between the cracks of grander frameworks of development co-operation and humanitarian assistance. Despite the seemingly glaring need to reduce the horrific impact of floods, droughts and wars, disaster mitigation and preparedness have neither the allure of directly 'saving lives', nor of providing an 'escape from poverty'. There are, however, signs that risk management is becoming a mainstream concern. Factors such as the need to address factors that do not fit into traditional slots on the relief-development continuum, the rising economic costs of disasters and a growing acknowledgement that aid will never cover more than a small fraction of the costs of disasters are all leading to new approaches, priorities and institutional configurations. A realisation that dealing with risk and insecurity is a central part of how poor people develop their livelihood strategies has begun to position disaster mitigation and preparedness within many poverty alleviation agendas. A number of long-standing challenges remain; most of all, the complexities of maintaining the political will that is needed to ensure that risk management becomes more than a passing fad.

Disaster Planning↗
PubMed2001

The pattern of tegument-capsid interaction in the herpes simplex virus type 1 virion is not influenced by the small hexon-associated protein VP26.

Examination of the three-dimensional structure of intact herpes simplex virus type 1 (HSV-1) virions had revealed that the icosahedrally symmetrical interaction between the tegument and capsid involves the pentons but not the hexons (Z. H. Zhou, D. H. Chen, J. Jakana, F. J. Rixon, and W. Chiu, J. Virol. 73:3210-3218, 1999). To account for this, we postulated that the presence of the small capsid protein, VP26, on top of the hexons was masking potential binding sites and preventing tegument attachment. We have now tested this hypothesis by determining the structure of virions lacking VP26. Apart from the obvious absence of VP26 from the capsids, the structures of the VP26 minus and wild-type virions were essentially identical. Notably, they showed the same tegument attachment patterns, thereby demonstrating that VP26 is not responsible for the divergent tegument binding properties of pentons and hexons.

Base Sequence↗
PubMed2001

The effect of the Gly16Arg polymorphism of the beta(2)-adrenergic receptor gene on plasma free fatty acid levels is modulated by physical activity.

The lipolytic effects of catecholamines are mediated through members of the beta(2)-adrenergic receptor (BAR-2) family. Previous studies have suggested that genetic variants in the BAR-2 gene may be associated with obesity in some populations. To our knowledge, no studies have directly examined the effects of this polymorphism on circulating nonesterified fatty acid (NEFA) levels. To explore this issue further, a cohort of 604 Caucasian individuals (aged 40-65 yr) was genotyped for a common polymorphism in the BAR-2 gene (Gly16Arg), and the relationships between genotype, body mass index (BMI), NEFA, and lipid levels were examined. Women bearing the Arg16 allele had higher BMI values (P < 0.01) than Gly16Gly women. Women carriers of the Arg16Arg genotype had lower fasting plasma NEFAs (P < 0.01) and greater suppression of NEFAs (P < 0.01) after an oral glucose load than women bearing the Gly16 allele. In multivariate analysis after adjustment for age, sex, and smoking status, the interaction between the BAR-2 genotype and BMI in determining fasting NEFA concentrations was statistically significant (P < 0.05). The availability of objective measures of total energy expenditure in this population permitted the further examination of interactions, particularly that between genotype and physical activity. In the population as a whole, after adjustment for confounding by age, smoking, and BMI, the effect of the Arg16Arg genotype on the suppression of NEFA levels was modified by physical activity level (P for interaction <0.05). These data suggest the existence in this population of a gene-physical activity interaction on NEFA levels.

Adult↗
PubMed2001

The association of race/ethnicity, socioeconomic status, and physician recommendation for mammography: who gets the message about breast cancer screening?

OBJECTIVES: This study investigated the association between physician recommendation for mammography and race/ethnicity, socioeconomic status, and other characteristics in a rural population. METHODS: In 1993 through 1994, we surveyed 1933 Black women and White women 52 years and older in 10 rural counties. RESULTS: Fifty-three percent of the women reported a physician recommendation in the past year. White women reported recommendations significantly more often than did Black women (55% vs 45%; odds ratio = 1.49). Controlling for educational attainment and income eliminated the apparent racial/ethnic difference. After control for 5 personal, 4 health, and 3 access characteristics, recommendation for mammography was found to be more frequent among women who had access to the health care system (i.e., had a regular physician and health insurance). Recommendation was less frequent among women who were vulnerable (i.e., were older, had lower educational attainment, had lower annual family income). CONCLUSIONS: Socioeconomic status, age, and other characteristics--but not race/ethnicity--were related to reports of a physician recommendation, a precursor strongly associated with mammography use. Efforts to increase physician recommendation should include complementary efforts to help women address socioeconomic and other barriers to mammography use.

Black or African American↗
PubMed2001

Work in progress. Integrating physicians' services in the home.

OBJECTIVE: While increasing acuity levels and the concomitant complexity of service demand that physicians be involved in in-home care, conflicting evidence and opinions do not show how this can best be achieved. DESIGN: A phenomenologic research design was used to obtain insights into the challenges and opportunities of integrating physicians' services into the usual in-home services in London, Ont. SETTING: Home care in London, Ont. PARTICIPANTS: Twelve participants included three patients, two family caregivers, two family physicians, the program's nurse practitioner, two case managers, and two community nurses. METHOD: In-depth interviews with a maximally varied purposeful sample of patients, caregivers, and providers were analyzed using immersion and crystallization techniques. MAIN FINDINGS: Findings revealed the potential for enhanced continuity of care and interdisciplinary team functioning. Having a nurse practitioner, interdisciplinary team-building exercises and meetings, regular face-to-face contact among all providers, support for family caregivers, and 24-hour coverage for physicians were found to be essential for success. CONCLUSION: Integration of services takes time, money, and sustained commitment, particularly when undertaken in geographically isolated communities. Informed choice and a fair remuneration system remain important considerations for family physicians.

Adult↗
PubMed2000

DNA sequence elements located immediately upstream of the -10 hexamer in Escherichia coli promoters: a systematic study.

We have made a systematic study of how the activity of an Escherichia coli promoter is affected by the base sequence immediately upstream of the -10 hexamer. Starting with an activator-independent promoter, with a 17 bp spacing between the -10 and -35 hexamer elements, we constructed derivatives with all possible combinations of bases at positions -15 and -14. Promoter activity is greatest when the 'non-template' strand carries T and G at positions -15 and -14, respectively. Promoter activity can be further enhanced by a second T and G at positions -17 and -16, respectively, immediately upstream of the first 'TG motif'. Our results show that the base sequence of the DNA segment upstream of the -10 hexamer can make a significant contribution to promoter strength. Using published collections of characterised E.coli promoters, we have studied the frequency of occurrence of 'TG motifs' upstream of the promoters' -10 elements. We conclude that correctly placed 'TG motifs' are found at over 20% of E.coli promoters.

Base Sequence↗
PubMed2000

An integrated map of human 6q22.3-q24 including a 3-Mb high-resolution BAC/PAC contig encompassing a QTL for fetal hemoglobin.

Genetic studies have previously assigned a quantitative trait locus (QTL) for hemoglobin F and F cells to a region of approximately 4 Mb between the markers D6S408 and D6S292 on chromosome 6q23. An initial yeast artificial chromosome contig of 13 clones spanning this region was generated. Further linkage analysis of an extended kindred refined the candidate interval to 1-2 cM, and key recombination events now place the QTL within a region of <800 kb. We describe a high-resolution bacterial clone contig spanning 3 Mb covering this critical region. The map consists of 223 bacterial artificial chromosome (BAC) and 100 P1 artificial chromosome (PAC) clones ordered by sequence-tagged site (STS) content and restriction fragment fingerprinting with a minimum tiling path of 22 BACs and 1 PAC. A total of 194 STSs map to this interval of 3 Mb, giving an average marker resolution of approximately one per 15 kb. About half of the markers were novel and were isolated in the present study, including three CA repeats and 13 single nucleotide polymorphisms. Altogether 24 expressed sequence tags, 6 of which are unique genes, have been mapped to the contig.

Base Sequence↗
PubMed2000

Essentials of the diagnosis of heart failure.

Although heart failure is a common clinical syndrome, especially in the elderly, its diagnosis is often missed. A detailed clinical history is crucial and should address not only current signs and symptoms of heart failure but also signs and symptoms that point to a specific cause of the syndrome, such as coronary artery disease, hypertension or valvular heart disease. It is important to determine whether the patient has had a previous cardiac event, in particular a myocardial infarction. The physical examination should include Valsalva's maneuver, a test that is highly specific and sensitive for the detection of left ventricular systolic and diastolic dysfunction in patients with heart failure. An electrocardiograph and a chest radiograph should also be obtained. Two-dimensional echocardiography of the heart helps differentiate systolic from diastolic dysfunction. Coronary angiography is indicated in patients with heart failure and anginal chest pain and should be strongly considered in patients with an electrocardiogram suggestive of ischemia or myocardial infarction.

Algorithms↗
PubMed2000

Precision measurement of cosmic-Ray antiproton spectrum

The energy spectrum of cosmic-ray antiprotons ( &pmacr;'s) has been measured in the range 0.18-3.56 GeV, based on 458 &pmacr;'s collected by BESS in a recent solar-minimum period. We have detected for the first time a characteristic peak at 2 GeV of &pmacr;'s originating from cosmic-ray interactions with the interstellar gas. The peak spectrum is reproduced by theoretical calculations, implying that the propagation models are basically correct and that different cosmic-ray species undergo a universal propagation. Future BESS data with still higher statistics will allow us to study the solar modulation and the propagation in detail and to search for primary &pmacr; components.

Journal Article↗
PubMed2000

Dissociation of G-protein alpha from rhabdomeric membranes decreases its interaction with rhodopsin and increases its degradation by calpain.

Photoactivation of invertebrate rhodopsin activates a GTP-binding protein, Gq, which in turn activates a phospholipase C (PLC) enzyme. Gqalpha is a membrane-associated protein that is progressively released from the membrane by washing with buffers containing increasing concentrations of beta-mercaptoethanol (beta-ME). Isolated, soluble Gqalpha showed a decreased ability to be activated by rhodopsin but was more active in stimulating PLC when compared with the membrane-associated form of Gqalpha. The calcium-activated protease, calpain, selectively cleaved the soluble but not the membrane-bound form of Gqalpha. Calpain cleaved a small peptide from the amino-terminus of Gqalpha reducing the ability of the G-protein to bind GTP. The uncoupling of Gqalpha from rhodopsin and subsequent calcium-dependent proteolysis to further inactivate the G-protein may therefore be a regulatory mechanism of light adaptation in rhabdomeric photoreceptors.

Animals↗
PubMed2000

Beyond church attendance: religiosity and mental health among rural older adults.

Data from 2 independent random samples of the population of community-dwelling older adults in eastern North Carolina are used to assess the effects of Christian religious subdimensions, including church attendance and participation, belief that religious faith affects health, and belief that prayer and God combine with medical treatment to cure illness, upon mental health. Self-reported religiosity in this population across dimensions is described and the effects of selected demographic characteristics upon religiosity are assessed. Lastly, the main effects of demographic characteristics, religiosity, and health status upon the mental health of respondents are explored. Findings suggest that Christian religious beliefs and practices are widespread in this mainly rural population and that females and African American elderly people are more likely than others to profess religious beliefs and to participate in church-related activities. Multivariate results suggest that reduced health status, including functional ability, combines with limited participation in church activities to result in poorer self-rated mental health and more symptoms of depression. The implications of the findings for the role of Christian religiosity in health and mental health are discussed.

Journal Article↗