Search PubMed⌕ Search

Biomedical subjects

John Lynch

Publications and source records attributed to John Lynch.

At least 55 records · Page 3Linked to original sources
PubMed2004

The role of "genetics" in popular understandings of race in the United States.

The increase in public representation of the science-based concept "genetics" in the mass media might be expected to have a major impact on public understanding of the concept of "race." A model of lay understandings of the role of genetics in the contemporary United States is offered based on focus group research, random digit dial surveys, and community based surveys. That model indicates that lay people identify are primarily by physical features, but these identifications are categorized into a variety of groupings that may be regional, national, or linguistic. Although they believe that physical appearance is caused largely by genetics, and therefore that race has a genetic basis, they do not uniformly conclude, however, that all perceived racial characteristics are genetically based. Instead, they vary in the extent to which they attribute differences to cultural, personal, and genetic factors.

Genetics↗
PubMed2004

Hurling alone? How social capital failed to save the Irish from cardiovascular disease in the United States.

OBJECTIVES: We performed a historical review of cardiovascular risk profiles of Irish immigrants to the United States, 1850-1970, in regard to lifestyle, socio-economic circumstances, and social capital. METHODS: We analyzed US Census data from 1850-1970, area-based social and epidemiological data from Boston, data from Ireland's National Nutrition Surveillance Centre, and literature on Irish migration. RESULTS: The Irish were consistently at increased risk of cardiovascular diseases, a risk that related initially to material deprivation, across the life course of at least 2 generations. CONCLUSIONS: The principal difference between the Irish and other disadvantaged immigrant groups, such as the Italians, was dietary habits influenced by experiences during the Irish famine. Although there was a psychosocial component to the disadvantage and discrimination they experienced as an ethnic group, the Irish also exhibited strong community networks and support structures that might have been expected to counteract discrimination's negative effects. However, the Irish's high levels of social capital were not protective for cardiovascular disease.

Boston↗
PubMed2004

Gene therapy, fundamental rights, and the mandates of public health.

Recent and near-future developments in the field of molecular biology will make possible the treatment of genetic disease on an unprecedented scale. The potential applications of these developments implicate important public policy considerations. Among the questions that may arise is the constitutionality of a state-mandated program of gene therapy for the purpose of eradicating certain genetic diseases. Though controversial, precedents of public health jurisprudence suggest that such a program could survive constitutional scrutiny. This article provides an overview of gene therapy in the context of fundamental rights and the mandates of public health.

Abortion, Induced↗
PubMed2003

Cervical arterial dissection: time for a therapeutic trial?

BACKGROUND AND PURPOSE: Cervical arterial dissection is a major cause of stroke in young adults, yet despite standard treatment with anticoagulants or antiplatelet drugs, its management remains uncertain. The goal of this study was to assess the natural history of the disorder and to decide on the feasibility of a therapeutic trial. METHODS: Collaborating members of the Canadian Stroke Consortium prospectively enrolled consecutively referred patients with angiographically proven acute vertebral or carotid arterial dissection. Data recorded included clinical and radiological details, recurrence of ischemic cerebral events, and medical or surgical treatment. RESULTS: Of 116 patients, 67 had vertebral and 49 had carotid dissections, with no difference in age or sex. In 68 (59%), trauma occurred at the time of dissection. During the course of a 1-year follow-up, at least 17 patients (15%) had recurrent transient ischemic attacks, stroke, or death, mainly in the weeks immediately after the dissection. In 105 patients with complete follow-up, the event rate in those treated with anticoagulants was 8.3% and in those treated with aspirin was 12.4%, a nonsignificant difference of 4.1%. Using these data, we calculate that for a 2-arm trial (aspirin versus anticoagulants) with 80% power and 5% significance, 913 patients are needed in each group. CONCLUSIONS: From our data indicating an initial relatively high recurrence rate, a multicenter trial of anticoagulants versus aspirin involving a total of 2000 patients is feasible.

Adult↗
PubMed2003

Cdx1 inhibits the proliferation of human colon cancer cells by reducing cyclin D1 gene expression.

The transcription factor Cdx1 regulates intestine-specific gene expression and enterocyte differentiation. It has been hypothesized to play a role in regulating intestinal cell proliferation; however, the mechanism for this effect remains elusive. In a prior study, we demonstrated that Cdx1 expression reduced the proliferation of a nontransformed intestinal cell line. This study tests the hypothesis that Cdx1 expression inhibits colon cancer cell proliferation by reducing cyclin D1 gene expression. Cdx1 expression markedly reduced cancer cell proliferation and DNA synthesis and induced an accumulation of cells in G0/G1. A transcriptionally inactive Cdx1 mutant could not elicit this effect, suggesting that it required Cdx1 transcriptional activity. Cdx1 expression increased the hypophosphorylation of the retinoblastoma (pRb) and p130 proteins. Reductions in G1 cyclin-dependant kinase (cdk) activity accompanied this effect. Cyclin D1 mRNA and protein levels were diminished by Cdx1 expression. Restoration of cyclin D1 expression reversed the G0/G1 block and induced pRb hyperphosphorylation. Lastly, Cdx1 expression did not alter cyclin D1 mRNA stability but did reduce cyclin D1 promoter activity, suggesting that Cdx1 acts to diminish cyclin D1 gene transcription. We conclude that Cdx1 reduces the proliferation of human colon cancer cells by reducing cyclin D1 gene transcription.

Animals↗
PubMed2003

Social inequalities in health- do they diminish with age? Revisiting the question in Sweden 1999.

BACKGROUND: Individuals with low income have poorer health and should, therefore, have higher health expenditure than people with high income particularly in countries with a universal health care system. However, it has been discussed if social inequities in health diminish with age and we, hence, aimed to analyse this question. METHODS: We performed an age stratified cross-sectional analysis using averages, logistic and linear regression modelling of health care contacts, health care expenditures and mortality in relation to individual income in five groups by quintiles. The population consisted of all the 249,855 men aged 40 to 80 years living in the county of Skåne, Sweden during 1999. RESULTS: For working-age people (40-59 year old) we find a clear socioeconomic gradient with increasing probability of health care contact, relative expenditure and mortality as income decreased. The point estimations for 1st (highest)-2nd-3rd-4th and 5th (lowest) income groups were: (1.00-1.13-1.21-1.42 and 1.15), (1.00-1.16-1.29-1.69 and 1.89) and (1.00-1.35-1.44-2.82 and 4.12) for health care contact, relative expenditure and mortality respectively. However, in the elderly (75-80 year old) these point estimates were (1.00-0.83-0.59-0.61 and 0.39), (1.00-1.04-1.05-1.02 and 0.96) and (1.00-1.06-1.30-1.33 and 1.49). CONCLUSIONS: As expected among working-age individuals, lower income was associated with higher health care contact, relative expenditure and mortality. However, the existence of opposite socioeconomic gradients in health care utilisation and mortality in the elderly suggests that factors related to a high income might condition allocation of resources, or that current medical care is ineffective to treat determinants of income differences in mortality occurring earlier in the lifecourse.

Journal Article↗
PubMed2003

Xenon attenuates cardiopulmonary bypass-induced neurologic and neurocognitive dysfunction in the rat.

BACKGROUND: With clinical data suggesting a role for excitatory amino acid neurotransmission in the pathogenesis of cardiopulmonary bypass (CPB)-associated brain injury, the current study was designed to determine whether xenon, an N-methyl-D-aspartate receptor antagonist, would attenuate CPB-induced neurologic and neurocognitive dysfunction in the rat. METHODS: Following surgical preparation, rats were randomly divided into four groups: (1) sham rats were cannulated but did not undergo CPB; (2) CPB rats were subjected to 60 min of CPB using a membrane oxygenator receiving a gas mixture of 30% O2, 65% N2, and 5% CO2; (3) CPB + MK801 rats received MK801 (0.15 mg/kg intravenous) 15 min prior to 60 min of CPB with the same gas mixture; and (4) CPB + xenon rats underwent 60 min of CPB using an oxygenator receiving 30% O2, 60% xenon, 5% N2, and 5% CO2. Following CPB, the rats recovered for 12 days, during which they underwent standardized neurologic and neurocognitive testing (Morris water maze). RESULTS: The sham and CPB + xenon groups had significantly better neurologic outcome compared to both the CPB and CPB + MK801 groups on postoperative days 1 and 3 (P < 0.05). Compared to the CPB group, the sham, CPB + MK801, and CPB + xenon groups had better neurocognitive outcome on postoperative days 3 and 4 (P < 0.001). By the 12th day, the neurocognitive outcome remained significantly better in the CPB + xenon group compared to the CPB group (P < 0.01). CONCLUSION: These data indicate that CPB-induced neurologic and neurocognitive dysfunction can be attenuated by the administration of xenon, potentially related to its neuroprotective effect via N-methyl-D-aspartate receptor antagonism.

Animals↗
PubMed2003

Measuring contextual characteristics for community health.

OBJECTIVE: To conceptualize and measure community contextual influences on population health and health disparities. DATA SOURCES: We use traditional and nontraditional secondary sources of data comprising a comprehensive array of community characteristics. STUDY DESIGN: Using a consultative process, we identify 12 overarching dimensions of contextual characteristics that may affect community health, as well as specific subcomponents relating to each dimension. DATA COLLECTION: An extensive geocoded library of data indicators relating to each dimension and subcomponent for metropolitan areas in the United States is assembled. PRINCIPAL FINDINGS: We describe the development of community contextual health profiles, present the rationale supporting each of the profile dimensions, and provide examples of relevant data sources. CONCLUSIONS: Our conceptual framework for community contextual characteristics, including a specified set of dimensions and components, can provide practical ways to monitor health-related aspects of the economic, social, and physical environments in which people live. We suggest several guiding principles useful for understanding how aspects of contextual characteristics can affect health and health disparities.

Community Health Planning↗
PubMed2003

Relative or absolute standards for child poverty: a state-level analysis of infant and child mortality.

OBJECTIVES: The purpose of the present study was to compare the associations of state-referenced and federal poverty measures with states' infant and child mortality rates. METHODS: Compressed mortality and Current Population Survey data were used to examine relationships between mortality and (1) state-referenced poverty (percentage of children below half the state median income) and (2) percentage of children below the federal poverty line. RESULTS: State-referenced poverty was not associated with mortality among infants or children, whereas poverty as defined by national standards was strongly related to mortality. CONCLUSIONS: Infant and child mortality is more closely tied to families' capacity for meeting basic needs than to relative position within a state's economic hierarchy.

Adolescent↗
PubMed2003

Cardiorespiratory fitness and vigorous leisure-time physical activity modify the association of small size at birth with the metabolic syndrome.

OBJECTIVE: Small size at birth has been associated with components of the metabolic syndrome, but little is known about the association with the metabolic syndrome itself or whether leisure-time physical activity (LTPA) and cardiorespiratory fitness modify that association. We studied the association of size at birth with the metabolic syndrome. RESEARCH DESIGN AND METHODS: Birth weight and length, the metabolic syndrome (World Health Organization criteria), LTPA over the previous 12 months, and VO(2max) were assessed in 462 nondiabetic middle-aged Finnish men who were part of a population-based cohort study. RESULTS: Men with a ponderal index (kg/m(3)) at birth in the lower third had higher fasting insulin and glucose levels than men in the upper third in age-adjusted analyses and were at least twofold more likely to have the metabolic syndrome, even in men without cardiovascular disease. Adjustment for childhood or adult socioeconomic status or adult BMI did not attenuate the association. Thinness at birth was even more clearly associated with hyperinsulinemia and the metabolic syndrome in men engaging in <25 min/wk of vigorous LTPA and in men with a VO(2max) <28.6 ml x kg(-1) x min(-1) or <2.44 l/min. In active and fit men, however, the association was absent. CONCLUSIONS: Small size at birth was associated with the metabolic syndrome in middle-aged men already before development of diabetes or cardiovascular disease. Thinness at birth may carry with it lifelong metabolic consequences, but regular strenuous physical activity and maintenance of cardiorespiratory fitness may alleviate or eliminate those consequences.

Body Mass Index↗
PubMed2002

Impact of undergoing prostate carcinoma screening on prostate carcinoma-related knowledge and distress.

BACKGROUND: Despite the ongoing controversy regarding the utility of prostate carcinoma (PCa) screening, the prevalence of asymptomatic men who participate in free PCa screening programs is on the rise. However, this increased awareness has not been associated with increased knowledge about the potential limitations of PCa creening. We conducted a prospective assessment to delineate men's motivations for undergoing screening and to determine the impact of screening on psychological distress and on men's knowledge about PCa screening. METHODS: We conducted two telephone interviews with a group of 136 men registered to undergo free PCa screening at two hospital-based sites. The first interview was conducted before screening and the second interview followed receipt of the screening results. Interviews assessed demographics and screening history, reasons for undergoing the current screening, cancer-related and general psychological distress, knowledge of risk factors for PCa, and knowledge of the benefits and limitations of screening. Only participants with normal screening results were included in these analyses. RESULTS: "Seeking peace of mind about prostate cancer" was rated as the most important reason for undergoing screening. PCa-related distress decreased following receipt of a negative result (P < 0.01). Stratified analyses indicated that this was particularly true among younger men and African American men (both Ps < 0.001). Awareness of the benefits of screening was very high, but awareness of limitations was low, with fewer limitations reported following screening compared with prescreening (P < 0.01). Although awareness of the established risk factors improved following screening, controversial risk factors (i.e., those with limited empirical support) and factors that were unrelated to PCa risk were also rated as more important in the development of PCa than they were before screening (all Ps < 0.05). Therefore, the results may reflect that following screening, participants were simply more likely to endorse plausible risk factors, rather than actually reflecting an increase in participants' knowledge. CONCLUSIONS: These results suggest the importance of developing informed consent procedures and educational programs for the asymptomatic men who participate in free prostate screening programs each year, as the decision to be screened is being made without the benefit of a full understanding of the current state of medical knowledge about PCa screening. Until the definitive results of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial are available, improved patient education is needed to assist men in making screening decisions consistent with their own preferences.

Black or African American↗
PubMed2002

Periodontitis in the United States: beyond black and white.

OBJECTIVES: This paper examines whether historical disparities in periodontal status between African Americans and whites in the United States have increased, decreased, or remained the same over the 15-year period between the First National Health and Nutrition Examination Survey (NHANES I, 1971-74) and the Third National Health and Nutrition Examination Survey (NHANES III, 1988-94). METHODS: This study compared the magnitude of the relative and absolute differences in the periodontal status of African-American and white adults in NHANES I and again in NHANES III. RESULTS: The prevalence of periodontitis in the US adult population in NHANES I was 31.6 percent, with African Americans exhibiting higher prevalence than whites. In NHANES III, using a different case-definition for periodontitis, the overall prevalence was 11.9 percent, with African Americans again exhibiting higher prevalence than whites. The magnitude of the intrasurvey relative and absolute differences between African Americans and whites increased between NHANES I and NHANES III. This finding remained after adjustment in the logistic regression analyses. After adjustment for all covariates in the model, African Americans were more likely to exhibit periodontitis than whites in both NHANES I (odds ratio [OR] = 1.31; 95% confidence intervals [CI] = .78, 2.19) and NHANES III (OR = 2.09; 95% CI = 1.68, 2.60). However, the CI included 1.00 in NHANES I. CONCLUSIONS: Disparities in periodontitis between African Americans and whites are pervasive and have increased over time. This increase appears to be driven by social, cultural, and behavioral factors.

Adolescent↗
PubMed2002

Determinants of outcome for patients admitted to a long-term ventilator unit.

BACKGROUND: This prospective cohort study was done to identify determinants of successful weaning from mechanical ventilation among patients admitted to the 10-bed long-term ventilator unit (LTVU) of a teaching hospital. METHODS: Prospective patient surveillance and data collection were done on 472 patients admitted to the LTVU over a 4-year period (January 1996 to December 1999). RESULTS: Multiple logistic regression analysis showed that the absence of home mechanical ventilation at the time of hospital admission, absence of intensive care unit (ICU) readmission, and admission to the LTVU from a nonmedical service were independently associated with successful weaning. No statistical difference between hospital survivors and nonsurvivors was associated with length of stay in the LTVU and length of stay in the hospital. CONCLUSIONS: Patients admitted to an LTVU require prolonged hospitalizations and intensive resource utilization. These data suggest that improved methods for identifying patients who are unlikely to benefit from prolonged mechanical ventilation may assist physicians in their discussions with patients and family members as they consider various treatment options.

Aged↗
PubMed2002

Is there homogeneity in periodontal health between African Americans and Mexican Americans?

OBJECTIVES: This study identified and contrasted prevalence and predictors of periodontitis among African Americans, Mexican Americans, and non-Hispanic Whites in the US adult population. DESIGN: Cross-sectional study. This study compared those with and without periodontitis in each racial/ethnic group. METHODS: This study was limited to records of US African-American, Mexican-American, and non-Hispanic White adults at least 17 years of age who received a complete periodontal assessment as part of the dental examination in the third National Health and Nutrition Examination Survey (1988-1994). RESULTS: Despite the findings that Mexican Americans were less educated, poorer, and had less insurance coverage than African Americans, Mexican Americans had a similar prevalence of periodontitis as non-Hispanic Whites. African Americans had the highest prevalence among all groups. A similar scenario was observed in the multiple logistic analyses. CONCLUSIONS: Mexican Americans had periodontal health profiles closer to non-Hispanic Whites than did African Americans, despite the shared "minority" status. Public health research and practice should explicitly recognize that while "minorities" are considered a homogeneous group, they do not necessarily share the same health profiles.

Adolescent↗