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J Dorn

Publications and source records attributed to J Dorn.

At least 19 recordsLinked to original sources
PubMed2004

Oxidative stress and glucose levels in a population-based sample.

OBJECTIVES: To examine the relationship between markers of oxidative status and glucose on a population basis. STUDY DESIGN AND SETTING: We report here on a population-based sample of 1315 women and 981 men, aged 35-79 years, randomly selected from residents of Erie and Niagara Counties in western New York between 1996 and 1999. Thiobarbituric reactive substances (TBARS), erythrocyte glutathione (GSH) and plasma glutathione peroxidase (GSH-Px) were measured as markers of oxidative status. Study sample was categorized by quartiles of glucose, degree of abnormality of fasting glucose, and level of metabolic control in patients with diabetes. RESULTS: Men and women in the uppermost quartiles of glucose had higher levels of TBARS (men: Quartile 4 = 1.55 +/- 0.03, Quartile 1 = 1.36 +/- 0.03, women: 1.49 +/- 0.02, 1.30 +/- 0.02 nmol/ml) and lower levels of GSH (men: Quartile 4 = 1.57 +/- 0.03, Quartile 1 = 1.69 +/- 0.03, women: 1.71 +/- 0.03, 1.97 +/- 0.0 mmol/l packed RBCs). In women, compared with normal fasting glucose, impaired fasting glucose was associated with higher levels of TBARS (1.29 +/- 0.01 vs. 1.84 +/- 0.04 nmol/ml), lower levels of GSH (1.85 +/- 0.02 vs. 1.76 +/- 0.05 mmol/l packed RBCs), and higher GSH-Px activity (618.94 +/- 2.64 vs. 644.77 +/- 8.90 IU/l). In women, abnormal fasting glucose was associated with higher levels of TBARS (1.84 +/- 0.04 nmol/ml), lower levels of GSH (1.68 +/- 0.06 mmol/l packed RBCs), and higher levels of GSH-Px (647.72 +/- 9.87 IU/l) than normal or impaired fasting glucose. In men, abnormal fasting glucose was associated with higher TBARS (1.76 +/- 0.04 vs. 1.37 +/- 0.07 nmol/ml), and lower GSH (1.62 +/- 0.05 vs. 2.78 +/- 0.02 mmol/l packed RBCs), than normal fasting glucose. Poor metabolic control was associated with higher TBARS (men: 2.07 +/- 0.08 vs. 1.33 +/- 0.14 nmol/l, women: 2.02 +/- 0.09 vs. 1.35 +/- 0.18 nmol/l) and GSH-Px activity (men: 654.34 +/- 13.45 vs. 599.86 +/- 24.76, women: 660.61 +/- 13.25 vs. 579.42 +/- 27.42 IU/l). CONCLUSIONS: Glucose levels play a role in determining oxidative status in a population sample. The balance between oxidative and antioxidant processes appears to be sensitive to glucose levels with moderate elevations of glucose affecting the oxidative status.

Aged↗
PubMed2003

Automatic fluorescent tag localization II: Improvement in super-resolution by relative tracking.

We present an algorithm for the three-dimensional (3D) tracking of multiple fluorescent subresolution tags with super-resolution in images of living cells. Recently, we described an algorithm for the automatic detection of such tags in single frames and demonstrated its potential in a biological system. The algorithm presented here adds to the tag detector a module for relative tracking of the signals between frames. As with tag detection, the main problem in relative tracking arises when signals of multiple tags interfere. We propose a novel multitemplate matching framework that exploits knowledge of the microscope point spread function to separate the intensity contribution of each tag in image regions with signal interferences. We use this intensity splitting to reconstruct a template for each tag in the source frame and a patch in the target frame, which are both free of intensity contributions from other tag signals. Tag movements between frames are then tracked by seeking, for each template-patch pair, the displacement vector providing the best signal match in terms of the sum of squared intensity differences. Because template and patch generation of tags with overlapping signals are interdependent, the matching is carried out simultaneously for all tags, and in an iterative manner. We have examined the performance of our approach using synthetic 3D data and observed a significant increase in resolution and robustness as compared with our previously described detector. It is now possible to localize and track tags separated by a distance three times smaller than the Rayleigh limit with a relative positional accuracy of better than 50 nm. We have applied the new tracking system to extract metaphase trajectories of fluorescently tagged chromosomes relative to the spindle poles in budding yeast.

Algorithms↗
PubMed2002

Increased carotid intima-media thickness in children-adolescents, and young adults with a parental history of premature myocardial infarction.

AIMS: The present study was designed to test whether early carotid structural changes are demonstrable (by high resolution B-mode ultrasound) in children, adolescents and young adults with a history of premature parental myocardial infarction. METHODS AND RESULTS: One hundred and fourteen healthy young (5 to 30 years) subjects with a parental history of premature myocardial infarction and 114 age- and sex-matched control subjects were enrolled in the study. They were divided into two age groups: children and adolescents (age 5 to 18 years) (54 individuals with a parental history of premature myocardial infarction and their control subjects; mean age 12.8+/-3.8 years) and young adults (age 19 to 30 years) (60 individuals with a parental history and their controls; mean age 23.8+/-3.3 years). All subjects underwent high resolution B-mode ultrasonographic evaluation of common carotid artery intima-media thickness. Lipid profile, resting blood pressure, body mass index and smoking status were also evaluated. In both age groups, compared to controls, subjects with a parental history of premature myocardial infarction had increased intima-media thickness of common carotid arteries (mean of combined sites: age 5-18 years: 0.45+/-0.076 mm vs 0.40+/-0.066 mm in controls, P=0.008; age 19-30 years: 0.48+/-0.077 mm vs 0.45+/-0.078 mm in controls,P =0.007) Offspring of coronary patients showed an unfavourable lipid profile, however, the association between a parental history of premature myocardial infarction and carotid intima-media thickness was independent of lipids, apolipoproteins and other traditional risk factors. CONCLUSIONS: Vascular structural changes associated with a parental history of premature myocardial infarction are already detectable in childhood and adolescence and occur independently of several traditional cardiovascular risk factors.

Adolescent↗
PubMed2002

Minimal and best linear combination of oxidative stress and antioxidant biomarkers to discriminate cardiovascular disease.

BACKGROUND AND AIM: Free radicals have been implicated in the atherosclerotic process of coronary heart disease (CHD). Well-developed laboratory methods may make available a large number of biomarkers of individual oxidative stress and antioxidant status. Such markers are able to quantify different phases of the oxidative stress and antioxidant status of an individual. However, limited knowledge is available on how to combine these biomarkers to best discriminate between individuals with and without CHD. METHODS AND RESULTS: We evaluated combined discrimination properties of six biomarkers of oxidative stress and antioxidant status, as indicators of CHD, in a cross-sectional random sample of 968 white men and women from Buffalo, New York. Individuals with CHD had significantly higher levels of thiobarbuturic acid reacting substances (TBARS) and uric acid, and significantly lower levels of high-density lipoproteins (HDL) after adjusting for age and gender, when compared to healthy subjects. There were no significant differences in erythrocyte glutathione (GSH), trolox equivalent antioxidant capacity (TEAC), and glutathione peroxidase (GSHPx) levels. TBARS were found to be the best discriminating of the biomarkers when it was individually evaluated. TBARS discriminate 76.2% (95% C.I. 0.66-0.82) of the CHD cases from healthy controls. When combining TBARS, GSH, TEAC, HDL, uric acid and GSHPx, they discriminate 81.5% (95% C.I.: 0.67-0.90) of the area under the curve. CONCLUSIONS: These preliminary findings suggest that the combination of multiple markers of oxidative stress does not greatly improve ability to differentiate between individuals with and without CHD compared to the use of TBARS alone.

Adult↗
PubMed2001

Prognostic value of peak exercise systolic blood pressure on long-term survival after myocardial infarction.

This study examined the association between peak exercise systolic blood pressure and other exercise test parameters and the long-term (19-year) survival of 625 patients with myocardial infarction who were original participants of the National Exercise and Heart Disease Project, a 3-year (1976 to 1979) multicenter randomized exercise clinical trial. Results show that low peak exercise systolic blood pressure (< or =140 mm Hg) was associated with increased mortality throughout the 19 years of follow-up, and men with this finding obtained no survival benefit from participating in an exercise program.

Adult↗
PubMed2001

Correlates of compliance in a randomized exercise trial in myocardial infarction patients.

PURPOSE: Exercise-based rehabilitation programs have been associated with decreased morbidity and mortality after myocardial infarction. Unfortunately, attendance is often poor, and information is limited regarding predictors of long-term compliance to such programs. This study examined factors associated with exercise session compliance over 3 yr in male myocardial infarction (MI) survivors. METHODS: Subjects were participants in the National Exercise and Heart Disease Project, a 3-yr (1976-1979) multicenter, randomized clinical trial (N = 651); 308 men, 30-64 yr of age, were randomized to the exercise treatment group, that met three times/week throughout the study. Compliance was defined as the number of sessions attended/number of sessions conducted. Patient characteristics at enrollment were considered as possible predictors of compliance. RESULTS: Compliance decreased as time since enrollment increased with the largest decrease observed after the first 8 wk. Compliance correlated positively with exercise test measures [last completed stage (r = 0.17, P < 0.01), peak heart rate (r = 0.11, P = 0.06)], high density lipoprotein (HDL) cholesterol (r = 0.15, P = 0.10), age (r = 0.11, P = 0.07), and inversely with body mass index (r = -0.19, P = 0.001), sum of three skinfolds (r = -0.15, P < 0.01), total cholesterol (r = -0.18, P < 0.01), triglycerides (r = -0.16, P < 0.01), and depression (r = -0.09, P < 0.11). Current smokers were less compliant than former and nonsmokers (r = -0.21, P < 0.001). The correlations with last completed stage, BMI, skinfolds, total cholesterol, and smoking status were statistically significant. The model explained 22.2% of the variance in compliance (r2 = 0.222). Baseline work capacity was among the most consistent predictors of early and late compliance. CONCLUSION: Compliance decreased over time. Men already at high risk for repeat events due to elevated risk factors were less compliant. These findings have important clinical implications regarding screening, intervention, and participation in potential cardiac rehabilitation program dropouts.

Adult↗
PubMed2001

TBARS and cardiovascular disease in a population-based sample.

BACKGROUND: Oxygen radicals might play a crucial role in the pathogenesis of various diseases, including atherosclerosis. Thiobarbituric acid reaction substances (TBARS), a biomarker of oxidative stress, have been proposed as a summary measure of total circulating oxidation. However, there is no strong indication that circulating levels of TBARS are increased in patients with atherosclerosis. DESIGN: We evaluated the relation between TBARS and cardiovascular disease (CVD) in a cross-sectional random sample of white men and women from Buffalo, New York. METHODS: Logistic regression was used to estimate the risk associated with high levels of TBARS. The area under the ROC curve was used to evaluate the discriminating power of TBARS. RESULTS: After adjusting for age and gender, TBARS levels were significantly higher in those with prevalent CVD (OR= 1.73, 95% CI=1.32-2.38), compared to those without a CVD diagnosis. These OR were almost 50% higher after correcting for measurement error (ME) (OR=1.93, 95% CI=1.07-3.40). The area under the ROC curve was 0.69 (95% CI=0.62-0.77) and when corrected for ME reached 0.80 (95% CI=0.65-0.89). CONCLUSIONS: Our results indicate that elevated levels of TBARS were associated with increase risk of the prevalence of CVD, but this effect was no longer significant after adjusting for glucose.

Adult↗
PubMed2000

Maximal exercise systolic pressure, exercise training, and mortality in myocardial infarction patients.

The relation of maximal exercise systolic pressure to physical conditioning and to mortality was determined in 641 men with > or =1 myocardial infarctions. Each performed a standardized multistage exercise test before randomized assignment either to an exercise group or a control group and at scheduled periodic intervals over 3 years. This study compares 123 men with maximal exercise systolic pressures (MESP) of < or =140 mm Hg with 518 men whose maximal exercise systolic pressure was > or =140 mm Hg. At baseline, the 2 groups were comparable for age, entry time since the occurrence of the qualifying cardiac event, and reported use of antihypertensive medications. Men with low MESP used more beta blockers, had lower systolic pressure measurements at rest and by definition at maximal exercise, and lower work capacity than men with higher levels of MESP. Men with low MESP experienced: (1) no reduction in mortality with exercise conditioning (p<0.86), and (2) a significantly higher mortality rate over 3 years (p<0.003) compared with men with higher levels of MESP. The relation of a low MESP to mortality persisted: (1) whether MESP or work capacity increased from the baseline exercise test to the last performed exercise test, and (2) whether it was measured at low (<6 METs) or high (> or =6 METs) levels of work capacity. We conclude that low maximal exercise systolic blood pressure is a predictor of mortality and is associated with an ineffective training response in men with myocardial infarction.

Blood Pressure↗
PubMed2000

Decreasing sedentary behaviors in treating pediatric obesity.

BACKGROUND: Epidemiological studies have shown television watching to be a risk factor for the development of obesity in children. The effect of reducing television watching and other sedentary behaviors as a component of a comprehensive obesity treatment program has not been thoroughly tested. OBJECTIVE: To compare the influence of targeting decreases in sedentary behavior vs. increases in physical activity in the comprehensive treatment of obesity in 8- to 12-year-old children. DESIGN: Randomized, controlled outcome study. SETTING: Childhood obesity research clinic. DESIGN: Ninety families with obese 8- to 12-year-old children were randomly assigned to groups that were provided a comprehensive family-based behavioral weight control program that included dietary, and behavior change information but differed in whether sedentary or physically active behaviors were targeted and the degree of behavior change required. RESULTS: Results during 2 years showed that targeting either decreased sedentary behaviors or increased physical activity was associated with significant decreases in percent overweight and body fat and improved aerobic fitness. Self-reported activity minutes increased and targeted sedentary time decreased during treatment. Children substituted nontargeted sedentary behaviors for some of their targeted sedentary behaviors. CONCLUSION: These results support reducing sedentary behaviors as an adjunct in the treatment of pediatric obesity.

Behavior Therapy↗
PubMed2000

Analysis of genetic variability within the immunodominant epitopes of envelope gp41 from human immunodeficiency virus type 1 (HIV-1) group M and its impact on HIV-1 antibody detection.

The serodiagnosis of human immunodeficiency virus type 1 (HIV-1) infection primarily relies on the detection of antibodies, most of which are directed against the immunodominant regions (IDR) of HIV-1 structural proteins. Among these, the N-terminal region of gp41 contains cluster I (amino acids [aa] 580 to 623), comprising the cytotoxic T-lymphocyte epitope (AVERYLKDQQLL) and the cysteine loop (CSGKLIC), and cluster II (aa 646 to 682), comprising an ectodomain region (ELDKWA). To delineate the epitope diversity within clusters I and II and to determine whether the diversity affects serologic detection by U.S. Food and Drug Administration (FDA)-licensed enzyme immunoassay (EIA) kits, gp41 Env sequences from 247 seropositive persons infected with HIV-1 group M, subtypes A (n = 42), B (n = 62), B' (n = 13), C (n = 38), D (n = 41), E (n = 18), F (n = 27), and G (n = 6), and 6 HIV-1-infected but persistently seronegative (HIPS) persons were analyzed. While all IDR were highly conserved among both seropositive and HIPS persons, minor amino acid substitutions (<20% for any one residue, mostly conservative) were observed for all subtypes, except for B', in comparison with the consensus sequence for each subtype. Most importantly, none of the observed substitutions among the group M plasma specimens affected antibody detection, since all specimens (n = 152) tested positive with all five FDA-licensed EIA kits. Furthermore, all specimens reacted with a group M consensus gp41 peptide (WGIKQLQARVLAVERYLKDQQLLGIWGCSGKLICTTAVPWNASW), and high degrees of cross-reactivity (>80%) were observed with an HIV-1 group N peptide, an HIV-1 group O peptide, and a peptide derived from the homologous region of gp41 from simian immunodeficiency virus from chimpanzee (SIVcpz). Taken together, these data indicate that the minor substitutions observed within the IDR of gp41 of HIV-1 group M subtypes do not affect antibody recognition and that all HIV-1-seropositive specimens containing the observed substitutions react with the FDA-licensed EIA kits regardless of viral genotype and geographic origin.

AIDS Serodiagnosis↗
PubMed2000

Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study.

STUDY OBJECTIVES: Results from several studies have described a relationship between pulmonary function and both all-cause and cause-specific mortality. The purpose of this study was to investigate the predictive value of pulmonary function by gender after 29 years of follow-up. DESIGN: Prospective study with 29-year follow-up of the Buffalo Health Study cohort. PARTICIPANTS: Randomly selected sample of 554 men and 641 women, aged 20 to 89 years, from all listed households of the city of Buffalo, NY. MEASUREMENTS AND RESULTS: Baseline measurements were performed in 1960 to 1961. Pulmonary function was assessed based on FEV(1) expressed as the normal percent predicted (FEV(1)%pred). FEV(1)%pred adjusted by age, body mass index, systolic BP, education, and smoking status was inversely related to all-cause mortality in both men and women (p<0.01). A sequential survival analysis in participants who had a survival time of at least 5, 10, 15, 20, and 25 years after enrollment in the study was also performed. Except for men who survived for > 25 years, we observed a statistically significant negative association between FEV(1)%pred and all-cause mortality. FEV(1)%pred was also inversely related to ischemic heart disease (IHD) mortality. When participants were divided into quintiles of FEV(1)%pred, participants in the lowest quintile of FEV(1)%pred experienced significantly higher all-cause mortality compared with participants in the highest quintile of FEV(1)%pred. For the entire follow-up period, the adjusted hazard ratios for all-cause mortality were 2.24 (95% confidence interval [CI], 1.60 to 3.13) for men and 1. 81 (95% CI, 1.24 to 2.63) for women, respectively. Hazard ratios for death from IHD in the lowest quintile of FEV(1)%pred were 2.11 (95% CI, 1.20 to 3.71) and 1.96 (95% CI, 0.99 to 3.88) for men and women, respectively. CONCLUSIONS: These results suggest that pulmonary function is a long-term predictor for overall survival rates in both genders and could be used as a tool in general health assessment.

Adolescent↗
PubMed1999

Results of a multicenter randomized clinical trial of exercise and long-term survival in myocardial infarction patients: the National Exercise and Heart Disease Project (NEHDP).

BACKGROUND: This study examined whether a supervised exercise program improved 19-year survival in 30- to 64-year-old male myocardial infarction patients. METHODS AND RESULTS: The men (n=651) were participants in the National Exercise and Heart Disease Project, a 3-year multicenter randomized clinical trial conducted in the United States (1976-1979). The treatment group (n=315) exercised for 8 weeks in a laboratory. Thereafter, they jogged, cycled, or swam in a gymnasium/pool setting guided by an individualized target heart rate. Participants in the control group (n=319) were to maintain normal routines but not participate in any regular exercise program. Participants were followed up until their death or December 31, 1995. Cox proportional hazards analysis revealed the all-cause mortality risk estimates (95% CIs) in the exercise group compared with controls to be 0.69 (0.39 to 1.25) after an average follow-up of 3 years, 0.84 (0.55 to 1.28) after 5 years, 0.95 (0.71 to 1.29) after 10 years, 1.02 (0.79 to 1.32) after 15 years, and 1.09 (0.87 to 1. 36) after 19 years. Cardiovascular disease (CVD) mortality risk estimates (95% CI) for the same follow-up periods were 0.73 (0.37 to 1.43), 0.98 (0.60 to 1.61), 1.21 (0.79 to 1.60), 1.14 (0.84 to 1.54), and 1.16 (0.88 to 1.52). However, each 1-MET increase in work capacity from baseline to the end of the original trial resulted in consistent reductions in all-cause and CVD mortality risk at each follow-up period, regardless of initial work-capacity level. CONCLUSIONS: These findings indicate exercise-program participation resulted in nonsignificantly reduced mortality risks early in the follow-up period. Benefits diminished as time since participation increased, which suggests that the protective mechanisms associated with the program may be short term. Contamination between groups over time could also explain the diminished effects, because increased work capacity provided survival benefits up to 19 years.

Adult↗
PubMed1999

Trocar and instrument positioning system TISKA. An assist device for endoscopic solo surgery.

The assistance received by the surgeon from support personnel during surgical laparoscopy is extremely important. This includes the retracting of instruments and the positioning of the endoscope. However, human assistance is costly and often does not provide satisfaction for the surgeon. The aim of the project was to develop a mechanical arm capable of manipulating a laparoscopic instrument under the control of the operating surgeon. The system design is based on a particular kinematic construction that maintains an invariant point of constraint motion coincident with the trocar puncture site through the abdominal wall. The guidance system allows transparent and intuitive operation, and its setup is easy and quick. It may be adapted either as an instrument retractor or as an optic positioning device. A new generation of instrument positioning systems, with improved ergonomy, will be a first step toward the diffusion of solo surgery techniques in minimally invasive therapy. We believe this prototype represents a valid compromise between human and robotic control for conventional laparoscopic instruments.

Animals↗
PubMed1999

Viral and immunologic examination of human immunodeficiency virus type 1-infected, persistently seronegative persons.

Persons who were human immunodeficiency virus type 1 (HIV-1)-infected but who remained persistently seronegative (HIPS) on HIV-1 antibody tests were examined through AIDS case surveillance. Six such individuals (HIPS-1 to -4, -7, and -9) were examined to determine whether their persistent seronegativity was attributable to immune dysfunction or infection with atypical HIV. Of the 6, 4 had antibody titers to at least 1 other common pathogen. In vitro stimulation of peripheral blood mononuclear cells from HIPS-4 and HIPS-7 with pokeweed mitogen or phosphorothioate oligodeoxynucleotide (direct B cell mitogen) did not produce HIV-1-specific antibody. Reconstitution experiments with recombinant interleukin (rIL)-4 and rIL-12 also had no impact on antibody production. Virus isolates from HIPS-4 and -9 were R5X4-tropic, whereas HIPS-7 was CCR5-tropic only. Sequence analysis of long terminal repeat, p24, and env gp41 did not reveal any specific mutation, and phylogenetic analysis confirmed that all 6 virus specimens were HIV-1 subtype B. These data suggest that the lack of a detectable antibody response in these patients may be the result of immune dysfunction.

Amino Acid Sequence↗
PubMed1998

Dietary cardiovascular risk factors and serum cholesterol in an Old Order Mennonite community.

OBJECTIVES: Dietary and coronary heart disease risk factors in Old Order Mennonite men and women were examined. METHODS: A food frequency questionnaire was mailed to 250 Mennonites who had participated in a previous study of coronary heart disease risk factors. RESULTS: Mennonites consumed a diet high in total fat, saturated fats, and cholesterol. Men had lower average serum cholesterol levels (174 mg/dL) than women (191 mg/dL). CONCLUSIONS: The Mennonites' diet was similar to that of the overall US population in saturated fat percentage and higher in cholesterol. Serum cholesterol levels, adiposity, and blood pressure were lower than expected among Mennonite men, perhaps because of their higher levels of physical activity.

Adolescent↗
PubMed1989

Blood pressure and intracellular ion transport in childhood.

The available data on the association between the cellular handling of sodium and high BP indicate that alteration of these parameters could be linked to the level of high BP. Limited data are available with regard to the association between BP and these aspects of the intracellular ion metabolism in childhood. The study of intracellular ion metabolism in children could help clarify the pathogenesis and etiology of essential hypertension by providing an opportunity to study this relationship before the effects of possible determinants of adult BP (ie, age, body weight, diet, physical activity) affect ion transport and modify its effect on BP. Specifically, familial predisposition to hypertension, growth and maturation, and the various components of body size need to be studied further to determine their role in the relationship between Na-Li CT and RBC Na and BP. Better understanding of this complex association could help elucidate the pathophysiology of essential hypertension.

Biological Transport↗