Biomedical subjects

S L Norris

Publications and source records attributed to S L Norris.

At least 19 recordsLinked to original sources

PubMed2006

Comparative vaccine efficacy of different isoforms of recombinant protective antigen against Bacillus anthracis spore challenge in rabbits.

The next-generation human anthrax vaccine developed by the United States Army Medical Research Institute of Infectious Diseases (USAMRIID) is based upon purified Bacillus anthracis recombinant protective antigen (rPA) adsorbed to aluminum hydroxide adjuvant (Alhydrogel). In addition to being safe, and effective, it is important that such a vaccine be fully characterized. Four major protein isoforms detected in purified rPA by native PAGE during research and development were reduced to two primary isoforms in bulk material produced by an improved process performed under Good Manufacturing Practices (GMP). Analysis of both rPA preparations by a protein-isoaspartyl-methyl-transferase assay (PIMT) revealed the presence of increasing amounts of iso-aspartic acid correlating with isoform content and suggesting deamidation as the source of rPA charge heterogeneity. Additional purification of GMP rPA by anion exchange chromatography separated and enriched the two principal isoforms. The in vitro and in vivo biological activities of each isoform were measured in comparison to the whole GMP preparation. There was no significant difference in the biological activity of each isoform compared to GMP rPA when analyzed in the presence of lethal factor using a macrophage lysis assay. Vaccination with the two individual isoforms revealed no differences in cytotoxicity neutralization antibody titers when compared to the GMP preparation although one isoform induced more anti-PA IgG antibody than the GMP material. Most importantly, each of the two isoforms as well as the whole GMP preparation protected 90-100% of rabbits challenged parenterally with 129 LD50 of B. anthracis Ames spores. The equivalent biological activity and vaccine efficacy of the two isoforms suggests that further processing to separate isoforms is unnecessary for continued testing of this next-generation anthrax vaccine.

Animals↗

PubMed2006

Neutralizing antibody response to booster vaccination with the 17d yellow fever vaccine.

A retrospective review was conducted of yellow fever vaccination among laboratory workers receiving annual serologic assessment to determine the initial and long-term response after boosting. Patients were divided into three groups based on pre-vaccination serology: Group 1, 1:10; Group 2, 1:20-1:40 and Group 3, >1:40. The percent with > or = four-fold increase in titers after booster vaccination were: 78% (646/829, Group 1), 65% (79/121, Group 2) and 10% (8/79, Group 3) (p<0.0001). The median times to titer failure (<1:40) were 798 days (Group 1), 3340 days (Group 2) and 7709 days (Group 3) (p<0.0001). Pre-vaccination serology influenced the initial and long-term response to yellow fever booster vaccination.

Adult↗

PubMed2006

Effectiveness of community health workers in the care of persons with diabetes.

AIMS: The purpose of this systematic review was to examine the effectiveness of community health workers in supporting the care of persons with diabetes. METHODS: Computerized searches were conducted of multiple electronic bibliographic dababases until March 2004. We identified studies in any language and of any design that examined the effectiveness of diabetes-related interventions involving community health workers and reported outcomes in persons with diabetes. Results were synthesized narratively. RESULTS: Eighteen studies were identified, including eight randomized controlled trials. Most studies focused on minority populations in the USA. The roles and duties of community health workers in diabetes care were varied, ranging from substantial involvement in patient care to providing instrumental assistance in education sessions taught by other health professionals. Participants were generally satisfied with their contacts with community health workers and participant knowledge increased. Improvements in physiological measures were noted for some interventions and positive changes in lifestyle and self-care were noted in a number of studies. There were few data on economic outcomes, but several studies demonstrated a decrease in inappropriate health care utilization. CONCLUSIONS: Diabetes programmes include community health workers as team members in a variety of roles. There are some preliminary data demonstrating improvements in participant knowledge and behaviour. Much additional research, however, is needed to understand the incremental benefit of community health workers in multicomponent interventions and to identify appropriate settings and optimal roles for community health workers in the care of persons with diabetes.

Community Health Services↗

PubMed2005

Long-term non-pharmacologic weight loss interventions for adults with type 2 diabetes.

BACKGROUND: Most persons with type 2 diabetes are overweight and obesity worsens the metabolic and physiologic abnormalities associated with diabetes. OBJECTIVES: The objective of this review is to assess the effectiveness of lifestyle and behavioral weight loss and weight control interventions for adults with type 2 diabetes. SEARCH STRATEGY: Studies were obtained from computerized searches of multiple electronic bibliographic databases, supplemented with hand searches of selected journals and consultation with experts in obesity research. The last search was conducted May, 2004. SELECTION CRITERIA: Studies were included if they were published or unpublished randomized controlled trials in any language, and examined weight loss or weight control strategies using one or more dietary, physical activity, or behavioral interventions, with a follow-up interval of at least 12 months. DATA COLLECTION AND ANALYSIS: Effects were combined using a random effects model. MAIN RESULTS: The 22 studies of weight loss interventions identified had a 4,659 participants and follow-up of 1 to 5 years. The pooled weight loss for any intervention in comparison to usual care among 585 subjects was 1.7 kg (95 % confidence interval [CI] 0.3 to 3.2), or 3.1% of baseline body weight among 517 subjects. Other main comparisons demonstrated nonsignificant results: among 126 persons receiving a physical activity and behavioral intervention, those who also received a very low calorie diet lost 3.0 kg (95% CI -0.5 to 6.4), or 1.6% of baseline body weight, more than persons receiving a low-calorie diet. Among 53 persons receiving identical dietary and behavioral interventions, those receiving more intense physical activity interventions lost 3.9 kg (95% CI -1.9 to 9.7), or 3.6% of baseline body weight, more than those receiving a less intense or no physical activity intervention. Comparison groups often achieved significant weight loss (up to 10.0 kg), minimizing between-group differences. Changes in glycated hemoglobin generally corresponded to changes in weight and were not significant when between-group differences were examined. No data were identified on quality of life and mortality. AUTHORS' CONCLUSIONS: Weight loss strategies using dietary, physical activity, or behavioral interventions produced small between-group improvements in weight. These results were minimized by weight loss in the comparison group, however, and examination of individual study arms revealed that multicomponent interventions including very low calorie diets or low calorie diets may hold promise for achieving weight loss in adults with type 2 diabetes.

Adult↗

PubMed2005

Long-term non-pharmacological weight loss interventions for adults with prediabetes.

BACKGROUND: Most persons with prediabetes (impaired glucose tolerance or impaired fasting glucose) are overweight, and obesity worsens the metabolic and physiologic abnormalities associated with this condition. Prediabetes is an important risk factor for the development of type 2 diabetes. OBJECTIVES: The objective of this review was to assess the effectiveness of dietary, physical activity, and behavioral weight loss, and weight control interventions for adults with prediabetes. SEARCH STRATEGY: Studies were obtained from computerized searches of multiple electronic bibliographic databases, supplemented by hand searches of selected journals, and consultation with experts in obesity research. The last search was conducted May, 2004. SELECTION CRITERIA: Studies were included if they were published or unpublished randomized controlled trials in any language and examined weight loss or weight control strategies using one or more dietary, physical activity, or behavioral interventions, with a follow-up interval of at least 12 months. DATA COLLECTION AND ANALYSIS: Effects were combined using a random-effects model. MAIN RESULTS: Nine studies were identified, with a total of 5,168 participants. Follow-up ranged from 1 to 10 years. Quantitative synthesis was limited by the heterogeneity of populations, settings, and interventions and by the small number of studies that examined outcomes other than weight. Overall, in comparisons with usual care, four studies with a follow-up of one year reduced weight by 2.8 kg (95 % confidence interval (CI) 1.0 to 4.7) (3.3% of baseline body weight) and decreased body mass index by 1.3 kg/m(2) (95% CI 0.8 to 1.9). Weight loss at two years was 2.6 kg (95% CI 1.9 to 3.3) (three studies). Modest improvements were noted in the few studies that examined glycemic control, blood pressure, or lipid concentrations (P > 0.05). No data on quality of life or mortality were found. The incidence of diabetes was significantly lower in the intervention groups versus the controls in three of five studies examining this outcome at 3 to 6 years follow-up. AUTHORS' CONCLUSIONS: Overall, weight loss strategies using dietary, physical activity, or behavioral interventions produced significant improvements in weight among persons with prediabetes and a significant decrease in diabetes incidence. Further work is needed on the long-term effects of these interventions on morbidity and mortality and on how to implement these interventions in diverse community settings.

Adult↗

PubMed2005

Pharmacotherapy for weight loss in adults with type 2 diabetes mellitus.

BACKGROUND: Obesity is closely related to type 2 diabetes and long-term weight reduction is an important part of the care delivered to obese persons with diabetes. OBJECTIVES: To assess the efficacy of pharmacotherapy for weight loss in adults with type 2 diabetes. SEARCH STRATEGY: Computerized searches were performed of MEDLINE (January 1966 to May 2004), EMBASE (January 1974 to May 2004, Web of Science (January 1981 to May 2004, and other electronic bibliographic databases, supplemented with hand searches of reference lists and selected journals. SELECTION CRITERIA: Randomized, controlled trials were included where pharmacotherapy was used as the primary strategy for weight loss among adults with type 2 diabetes. Published and unpublished literature in any language and with any study design was included. DATA COLLECTION AND ANALYSIS: Two reviewers abstracted data and the quality of included studies was evaluated by assessing potential attrition, as well as selection and measurement bias, and a Jadad score was obtained. Effects were combined using a random effects model. MAIN RESULTS: A sufficient number of studies were available for a quantitative synthesis for fluoxetine, orlistat, and sibutramine. Twenty two randomized controlled trials were included in the review, with a total of 296 participants for fluoxitine, 2036 for orlistat, and 1047 for sibutramine. Pharmacotherapy produced modest reductions in weight for fluoxetine (5.1 kg (95% confidence interval [CI], 3.3 - 6.9) at 24 to 26 weeks follow up; orlistat 2.0 kg (CI, 1.3 - 2.8) at 12 to 57 weeks follow-up, and sibutramine 5.1 kg (CI, 3.2 - 7.0) at 12 to 52 weeks follow-up. Glycated hemoglobin also modestly and significantly reduced for fluoxetine and orlistat. Gastrointestinal side effects were common with orlistat; tremor, somnolence and sweating with fluoxetine; and palpitations with sibutramine. Some studies, using a variety of study designs, were available on other drugs and a significant decrease in weight was noted in three studies of mazindol, one of phenmetrazine, two of phentermine. No studies were identified that fit inclusion criteria for pseudophedrine, ephedra, sertraline, yohimbine, amphetamine or its derivatives, bupropion, topiramate, benzocaine, threachlorocitric acid, sertraline, and bromocriptine. AUTHORS' CONCLUSIONS: Fluoxetine, orlistat, and sibutramine can achieve statistically significant weight loss over 12 to 57 weeks. The magnitude of weight loss is modest, however, and the long-term health benefits remain unclear. The safety of sibutramine is uncertain. There is a paucity of data on other drugs for weight loss or control in persons with type 2 diabetes.

Adult↗

PubMed2005

The effectiveness of family interventions in people with diabetes mellitus: a systematic review.

AIMS: To conduct a systematic review of reports of published literature to assess which family interventions are effective in improving diabetes-related outcomes in people with diabetes and family members (blood or non-blood relatives) residing in their homes. METHODS: We searched computerized bibliographic databases (MEDLINE, EMBASE, PsycINFO, CINAHL, WOS, ERIC, Cochrane, CDP, and SocAbs) for randomized clinical trials published in any language that evaluated the effectiveness of family-based interventions with no age restriction. Only studies focused on interventions in young populations (< 18 years) and involving a parent were combined in a meta-analysis for glycated haemoglobin (GHb) using DerSimonian and Laird random effects model. Effect sizes for knowledge outcomes were estimated using the Cohen's d (standardized mean differences) formula. RESULTS: Our searches identified 19 randomized controlled trials. Positive effect sizes of family interventions on knowledge for five studies (N = 217) were demonstrated {0.94 [95% confidence interval (CI) 0.67, 1.82]}. A beneficial effect of interventions on GHb for eight studies (N = 505) was also observed using meta-analysis [-0.6 (95% CI -1.2, -0.1)]. CONCLUSIONS: Evidence suggests that family interventions in family or household members of people with diabetes may be effective in improving diabetes-related knowledge and glycaemic control.

Adult↗

PubMed2004

Development of an in vitro-based potency assay for anthrax vaccine.

The potency assay currently used to evaluate consistency of manufacture for the anthrax vaccine is contingent upon meeting specified parameters after statistical analysis of the percent survival and time to death of vaccinated guinea pigs after challenge with spores of a virulent strain of Bacillus anthracis. During the development of a new anthrax vaccine based upon recombinant protective antigen (rPA) adsorbed to aluminum hydroxide gel (Alhydrogel), we found that the serological response of female A/J mice, as measured by a quantitative anti-rPA IgG ELISA, may be an effective method to monitor a manufacturer's consistency for rPA-based vaccines. An advantage of the proposed in vitro-based potency assay is that it will not need stringent biosafety containment measures as required by the current guinea pig potency assay.

Animals↗

PubMed2001

Effectiveness of self-management training in type 2 diabetes: a systematic review of randomized controlled trials.

OBJECTIVE: To systematically review the effectiveness of self-management training in type 2 diabetes. RESEARCH DESIGN AND METHODS: MEDLINE, Educational Resources Information Center (ERIC), and Nursing and Allied Health databases were searched for English-language articles published between 1980 and 1999. Studies were original articles reporting the results of randomized controlled trials of the effectiveness of self-management training in people with type 2 diabetes. Relevant data on study design, population demographics, interventions, outcomes, methodological quality, and external validity were tabulated. Interventions were categorized based on educational focus (information, lifestyle behaviors, mechanical skills, and coping skills), and outcomes were classified as knowledge, attitudes, and self-care skills; lifestyle behaviors, psychological outcomes, and quality of life; glycemic control; cardiovascular disease risk factors; and economic measures and health service utilization. RESULTS: A total of 72 studies described in 84 articles were identified for this review. Positive effects of self-management training on knowledge, frequency and accuracy of self-monitoring of blood glucose, self-reported dietary habits, and glycemic control were demonstrated in studies with short follow-up (<6 months). Effects of interventions on lipids, physical activity, weight, and blood pressure were variable. With longer follow-up, interventions that used regular reinforcement throughout follow-up were sometimes effective in improving glycemic control. Educational interventions that involved patient collaboration may be more effective than didactic interventions in improving glycemic control, weight, and lipid profiles. No studies demonstrated the effectiveness of self-management training on cardiovascular disease-related events or mortality; no economic analyses included indirect costs; few studies examined health-care utilization. Performance, selection, attrition, and detection bias were common in studies reviewed, and external generalizability was often limited. CONCLUSIONS: Evidence supports the effectiveness of self-management training in type 2 diabetes, particularly in the short term. Further research is needed to assess the effectiveness of self-management interventions on sustained glycemic control, cardiovascular disease risk factors, and ultimately, microvascular and cardiovascular disease and quality of life.

Adaptation, Psychological↗

PubMed2000

Effectiveness of physician-based assessment and counseling for exercise in a staff model HMO.

BACKGROUND: Few primary care physicians routinely counsel for exercise, despite the benefits of physical activity and the high prevalence of inactivity. The objective of this study is to assess the effectiveness of Physician-Based Assessment and Counseling for Exercise (PACE), a brief, behavior-based tool for primary care providers counseling healthy adults. METHODS: This study is a randomized controlled trial of 812 patients age 30 years or older registered for well visits at 32 primary care physician offices at a staff model health maintenance organization. Intervention physicians were trained to deliver PACE exercise counseling protocols at the index visit, and one reminder telephone call occurred at 1 month. An enhanced intervention group received additional activity reminders. RESULTS: At the 6-month follow-up, the control group did not differ significantly from the intervention group for energy expended (2,048 kcal/week versus 2,108 kcal/ week, P = 0.77), time spent in walking or other moderate to vigorous activities (202 min/week versus 187 min/ week, P = 0.99), mental health, physical function, or behaviors previously shown to predict activity change. Among the intervention patients, the stages-of-change score for Contemplators increased significantly compared with controls (P = 0.03), but without a significant change in energy expended. Baseline levels of physical activity counseling were high (50%), as were baseline patient physical activity levels (61% exercised at least three times a week). CONCLUSIONS: These results suggest that a one-time PACE counseling session with minimal reinforcement, in a setting with high baseline levels of activity, does not further increase activity. The finding that Contemplators advanced in stage of behavior change suggests that further studies are needed to examine long-term, repeated counseling interventions.

Adult↗

PubMed1998

Women in medicine: shaping the future.

The dramatic increase in the number of women in medicine presents some new challenges to an old institution. This article provides an overview of current trends and future directions as greater numbers of women are entering medicine. The first section describes women's particular approach to medicine, including their motivations for pursuing medicine as a career, their specialty choices and practice patterns, their attitudes about patient care and doctor-patient relationships, and their advocacy for women's health issues. The second section documents women's negative experiences in medicine, such as higher stress levels than men, gender discrimination, sexual harassment, role strain, and a paucity of mentors and role models. In the final section, the authors suggest how medicine as an institution can change to better accommodate women.

Attitude of Health Personnel↗

PubMed1997

Early radionuclide scans for risk assessment in suspected acute myocardial infarction.

First-day thallium-201 myocardial perfusion scans and technetium-99m RBC gated scintiangiography were performed during the initial clinical and prognostic evaluation of 69 patients with suspected acute myocardial infarction. Patients were monitored for clinical course, diagnosis confirmation, and use of specialty services (cardiac catheterization, percutaneous balloon angioplasty, and cardiac surgery) during hospitalization. Myocardial infarction, confirmed in 20 patients, was associated with significantly more left ventricular dilatation, lower ejection fractions, lower peak left ventricular filling rates, wall motion abnormalities, and thallium-201 perfusion defects than nonmyocardial infarction patients. Among all patients, left ventricular dilatation carried a relative risk of myocardial infarction of 5.8; low ejection fraction and right ventricular dilatation were strongly associated with myocardial infarction. A logistic model for congestive heart failure included: left ventricular dilation, lower mean left ventricular filling rates and time to peak filling rates, and abnormal thallium-201 lung:heart uptakes. Among nonmyocardial infarction patients, subsequent cardiac catheterization was predicted by the presence of anterior thallium-201 perfusion defects, Killip functional class II-III, and ischemia on ECG. These findings suggest that early detection of myocardial perfusion defects and cardiac dysfunction by radionuclide scans enhances initial evaluation of suspected acute myocardial infarction patients. Additional studies are needed to confirm these findings.

Analysis of Variance↗

PubMed1994

MRI-derived ventricular volume curves for the assessment of left ventricular function.

To assess the utility of double oblique, ECG-gated 1H magnetic resonance (MR) derived volume curves for assessing LV function, cardiac short axis images were acquired with a fast field echo technique. We applied this methodology to assess left ventricular function in three groups: normals, patients with left ventricular hypertrophy, and dilated cardiomyopathy. Six slices with 16-20 phases per RR interval were analyzed, representing the initial 75-80% of the cardiac cycle. For each slice, the endocardial border of the left ventricular (LV) chamber was manually traced. Using Simpson's rule, the total LV volume at a given phase was determined considering the traced area, thickness and position in three-dimensional space of each of the six constituent slices. The calculated volumes were plotted against time and the stroke volume, ejection fraction and cardiac output were determined. The volume vs time plots for the systolic and diastolic portions of the curve were individually fit to third degree polynomials using a least squares approximation. From the fit curves, the following data were extracted: the mean slope (dV/dT) during filling and emptying, and the time to 1/4, 1/3 and 1/2 filling and emptying. These parameters are valuable indices of the functional status of the myocardium; thus, accurate and useful estimates of LV function can be obtained using MRI derived volume curves in normal and abnormal states.

Cardiac Volume↗

PubMed1994

One-year prospective replication study of an untreated sample of community dysthymia subjects.

This study replicates an earlier naturalistic-prospective investigation of nontreatment, community DSM-III-R dysthymia subjects. Major goals were to determine spontaneous remission rates and monitor the stability of psychosocial functioning levels over time. Twenty-four dysthymia subjects were followed for 1 year. Three remissions (13%) were diagnosed at the final interview. At a 4-year diagnostic follow-up contact with the remitters only, one remitter had relapsed and two remained in remission. Subjects were monitored for depressive symptom intensity, personality functioning, general medical distress, cognitive functioning, coping stylistics, interpersonal functioning, quality of their social support resources, and general family functioning. Stable levels of psychosocial functioning were maintained across all measures over the 1-year period. Current psychometric findings confirm the conclusions of the earlier nontreatment prospective study that dysthymia is a chronic mood disorder with stable psychosocial features and is unlikely to remit spontaneously over time.

Adaptation, Psychological↗

PubMed1994

Comparison of a community dysthymia sample at screening with a matched group of nondepressed community controls.

The primary goal of the study was to compare the psychosocial functioning of an untreated, community sample of DSM-III-R dysthymia subjects (N = 24) at screening to that of a matched sample of community nondepressed volunteers (N = 18) with no lifetime or current history of axis I disorders. Subjects were compared across a number of psychosocial indices. The dysthymics were found to be less sociable (introversion) and clinically high on neuroticism-instability, external in regard to their causal attributions, less stable for positive uncontrollable events and more stable and global for negative uncontrollable events, relying more on coping strategies such as wishful thinking and self-blame, more interpersonally submissive and hostile, and to have a poorer social support-resource network. In addition, the dysthymics reported more family dysfunction and a higher rate of negative major life events.

Adaptation, Psychological↗

PubMed1993

Risk factors and mortality among black, Caucasian, and Latina women with acute myocardial infarction.

The purpose of this study was to examine the clinical outcome of acute myocardial infarction among women of three ethnic/racial groups and to determine whether observed differences in outcome are explained by differences in associated risk factors. Nine hundred seventeen (917) consecutive admissions occurred among 810 women, of whom 347 (42.8%) were Caucasian, 258 (31.9%) were black, and 205 (25.3%) were Latina. The overall mortality rate was 13%; the Caucasian rate was significantly higher than the Latina rate (16.9% vs 7%, p < 0.01), as was the black rate (13.8% vs 7%, p < 0.05). Comparing survivors with nonsurvivors among the three groups, hypertension was more common for survivors among blacks, as was a history of angina; in-hospital congestive failure was associated with a higher mortality for blacks and Caucasians, as was in-hospital angina for Caucasians. Univariate and multivariate logistic regression for the outcome variables of congestive failure, in-hospital angina, and mortality, showed race to be a significant factor in the lower mortality rate for Latinas in the univariate analysis. In the multivariate analysis, only in-hospital angina and congestive failure significantly influenced mortality. In this study of myocardial infarction among women of lower socioeconomic status, factors other than race were the primary influences on outcome.

Aged↗

PubMed1993

Altered muscle metabolism shown by magnetic resonance spectroscopy in sickle cell disease with leg ulcers.

We performed 31P magnetic resonance spectroscopy of gastrocnemius muscle at rest in 7 normal volunteers and 12 patients with sickle cell disease (7 with leg ulcers and 5 without leg ulcers but with painful crises). We measured intracellular pH and ratios of Pi to ATP, PCr to ATP and PCr to Pi (Pi = inorganic phosphate, ATP = adenosine triphosphate, and PCr = phosphocreatine). Magnetic resonance arteriograms were also performed. Significant differences were found for PCr/Pi ratios between normals and sickle cell disease patients with leg ulcers (p < 0.008). Magnetic resonance arteriograms were normal in volunteers and patients with sickle cell disease. The altered high energy phosphate metabolism in sickle cell disease with leg ulcers is consistent with muscle ischemia or hypoxia.

Adult↗

PubMed1992

Left ventricular filling pressure in sickle cell anemia.

Indirect left ventricular filling pressures were measured via balloon-tipped catheters in 11 studies of 10 patients with sickle cell anemia and cardiorespiratory symptomatology. Pulmonary capillary wedge pressures exceeded 12 mm Hg in 8 of 11 studies (8 of 10 patients). Mean pressures in mm Hg were: pulmonary capillary wedge, 16.5 +/- 4.2 (SEM); pulmonary artery, 38 +/- 16; brachial artery, 104 +/- 128; and right atrium, 11 +/- 4. The mean cardiac output was 8.8 +/- 3.1 L/min. The mean pulmonary vascular resistance was 237 +/- 122 dynes sec cm-5 and was significantly increased in 4 patients. In addition to further documentation of significantly elevated pulmonary artery pressures in sickle cell anemia patients with cardiopulmonary symptomatology, these data indicate that a contributory role for elevated left ventricular filling pressures must be considered in the pathogenesis of pulmonary hypertension in sickle cell anemia. Elevation of the pulmonary artery pressure was usually associated with elevation of the pulmonary capillary wedge pressure.

Adult↗