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Biomedical subjects

J J Anderson

Publications and source records attributed to J J Anderson.

At least 19 recordsLinked to original sources
PubMed1995

The effects of analytic software and scan analysis technique on the comparison of dual X-ray absorptiometry with dual photon absorptiometry of the hip in the elderly.

As part of a longitudinal comparison of bone mineral density (BMD) results originally obtained using a Lunar dual photon absorptiometry (DPA) scanner and later, using a Lunar dual X-ray absorptiometry (DXA) scanner, we compared femur results between DPA and DXA according to DXA analytic software (versions 1.3y and 1.4), and according to the method of placement of the femoral neck box (software algorithm or operator placement according to the appearance of the pair of images) in 58 elderly men and women. The mean BMD at each of three femoral sites was higher using DXA version 1.3y than DPA, but the use of software version 1.4 brought the BMD value closer to that of DPA at all sites. Of 58 scans, 12 (21%) were changed by the operator, resulting in an overall reduction in mean percent BMD difference between scan pairs of 79% (from 1.24% to 0.29%). Although the differences between the DPA/DXA software-driven analysis and the DPA/DXA operator-driven analysis appeared small (high r2 values and intra-class correlation coefficients), the increase in sample size that would be required for the same power to detect 2-year changes in BMD if the software-driven analysis was used instead of taking the time to perform the operator-driven analysis was 18%. The findings of this study highlight the need to account for upgrades in analytic software. Furthermore, we present a rational approach for the analysis of serial scans that has face validity and that results in smaller differences between pairs of scans performed on the same individual. The decision to adapt these methods must be based on the relative costs of reducing unwanted scan variability.

Absorptiometry, Photon↗
PubMed1992

Differential effect of subthalamic nucleus ablation on dopamine D1 and D2 agonist-induced rotation in 6-hydroxydopamine-lesioned rats.

The effect of unilateral subthalamic nucleus ablation on rotation in response to dopamine D1 and D2 agonists was examined in rats with a unilateral 6-OHDA lesion of the nigrostriatal pathway. Four to five weeks following subthalamic nucleus lesion, D2 agonist-induced rotation was reduced in subthalamic nucleus-lesioned rats relative to sham controls, although no such reduction in D1 agonist-induced circling occurred. However, 1-2 weeks following subthalamic nucleus lesion marked reductions occurred in both D1 and D2 agonist-induced rotation in subthalamic nucleus lesioned rats compared to sham controls. These results suggest that the subthalamic nucleus contributes primarily to the expression of D2-mediated motor behaviors, although ablation of the subthalamic nucleus may induce certain time-dependent compensatory mechanisms in other basal ganglia structures which affect D1-mediated actions.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Smoking eliminates the protective effect of oral estrogens on the risk for hip fracture among women.

OBJECTIVE: To determine if the association between smoking and osteoporotic fractures is related to the quantity of cigarettes smoked and to determine if smoking modifies the protection by estrogens. DESIGN: Cohort study. SETTING: A population-based cohort study, the Framingham Study. PARTICIPANTS: A total of 2873 women in the Framingham Study followed through examination 19 (1985-1987). MEASUREMENTS: All fractures of the proximal femur sustained by women in the Framingham Study from 1948 to 1987 were ascertained. At almost all examinations, available information on cigarette smoking was used to classify women as "ever smokers" compared with "never smokers," and, among "ever smokers," "current" compared with "former smokers." A similar classification for estrogen use was created. Information on potentially confounding variables was taken from each examination, including age, adiposity (weight/height2), alcohol consumption (ounces per week), and caffeine intake (coffee and tea). RESULTS: Overall, 207 hip fractures occurred among 34,700 woman-examinations of observation. In the entire cohort, current smoking did not appear to increase hip fracture risk (adjusted odds ratio [AOR], 1.22; 95% CI, 0.76 to 1.95; P greater than 0.2). Also overall, current estrogen use appeared to be protective (AOR, 0.38; CI, 0.12 to 1.21, P = 0.10). Among current smokers, however, estrogen use did not protect against fracture (AOR for current use, 1.26; CI, 0.29 to 5.45), whereas estrogen was protective in nonsmokers (AOR for current or past use, 0.37; CI, 0.19 to 0.75; P = 0.005). CONCLUSIONS: Overall, smoking does not appear to increase the risk for hip fracture in women. Although estrogen replacement protects nonsmokers from fracture, smoking may negate the protective skeletal effects of estrogen replacement therapy.

Administration, Oral↗
PubMed1992

Weight loss reduces the risk for symptomatic knee osteoarthritis in women. The Framingham Study.

OBJECTIVE: To evaluate the effect of weight loss in preventing symptomatic knee osteoarthritis in women. DESIGN: Cohort analytic study. SETTING: The Framingham Study, based on a sample of a defined population. PATIENTS: Women who participated in the Framingham Knee Osteoarthritis Study (1983 to 1985): Sixty-four out of 796 women studied had recent-onset symptomatic knee osteoarthritis (knee symptoms plus radiographically confirmed osteoarthritis) were compared with women without disease. MEASUREMENTS: Recalled date of symptom onset was used as the incident date of disease. Historical weight was defined as baseline body mass index up to 12 years before symptom onset. Change in body mass index was assessed at several intervals before the current examination. Odds ratios assessing the association between weight change and knee osteoarthritis were adjusted for age, baseline body mass index, history of previous knee injury, habitual physical activity level, occupational physical labor, smoking status, and attained education. RESULTS: Weight change significantly affected the risk for the development of knee osteoarthritis. For example, a decrease in body mass index of 2 units or more (weight loss, approximately 5,1 kg) over the 10 years before the current examination decreased the odds for developing osteoarthritis by over 50% (odds ratio, 0.46; 95% Cl, 0.24 to 0.86; P = 0.02). Among those women with a high risk for osteoarthritis due to elevated baseline body mass index (greater than or equal to 25), weight loss also decreased the risk (for 2 units of body mass index, odds ratio, 0.41; P = 0.02). Weight gain was associated with a slightly increased risk for osteoarthritis, which was not statistically significant. CONCLUSION: Weight loss reduces the risk for symptomatic knee osteoarthritis in women.

Aged↗
PubMed1992

AIMS2. The content and properties of a revised and expanded Arthritis Impact Measurement Scales Health Status Questionnaire.

OBJECTIVE: The goal of this project was to develop a more comprehensive and sensitive version of the Arthritis Impact Measurement Scales (AIMS). METHODS: AIMS scale items were revised, and 3 new scales were added to evaluate arm function, work, and social support. Sections were also added to assess satisfaction with function, attribution of problems to arthritis, and self-designation of priority areas for improvement. The new instrument was designated the AIMS2. A pilot test of format and content and a performance test of reliability and validity were carried out. RESULTS: Questionnaire completion times in a pilot study of 24 subjects averaged 23 minutes, and evaluations were positive regarding the instrument's length and ease of completion, and the subjects' willingness to complete serial forms and return them by mail. Measurement performance was tested in 408 subjects: 299 with rheumatoid arthritis (RA) and 109 with osteoarthritis (OA); 45 of these subjects completed a second AIMS2 within 3 weeks. Internal consistency coefficients for the 12 scales were 0.72-0.91 in the RA group and 0.74-0.96 in the OA group. Test-retest reliability was 0.78-0.94. All within-scale factor analyses produced single factors, except for mobility level in OA. Validity analyses in both the RA and the OA groups showed that patient designation of an area as a problem or as a priority for improvement was significantly associated with a poorer AIMS2 scale score in that area. Reliability, factor analysis, and validity results were consistent in age, sex, and education subgroups. Satisfaction was moderately correlated with level of function in the same health status area, and the satisfaction items formed a reliable scale. Responses to the arthritis attribution items showed that most dysfunction in this sample was due to arthritis. CONCLUSION: The AIMS2 is a revised and expanded health status questionnaire with excellent measurement properties that should be useful in arthritis clinical trials and in outcomes research.

Arm↗
PubMed1992

The rapid assessment of disease activity in rheumatology (radar) questionnaire. Validity and sensitivity to change of a patient self-report measure of joint count and clinical status.

OBJECTIVE: This study documents the measurement properties of a brief, self-administered questionnaire of disease signs and symptoms in patients with rheumatoid arthritis. METHODS: The Rapid Assessment of Disease Activity in Rheumatology (RADAR) questionnaire assesses joint pain/tenderness and clinical status. One hundred ninety-three pairs of RADAR forms were completed by 45 subjects and their assigned clinician evaluators. RESULTS: Subject-clinician agreement (intraclass correlation coefficients [ICC]) for joint pain/tenderness and clinical status ranged from 0.52 to 0.87 (P = 0.0001), with 83% greater than or equal to 0.65. The ICC for change in joint scores over 6 months was 0.83 (P = 0.0001). CONCLUSION: The 2-page RADAR questionnaire produces valid estimates of joint count and clinical status that are sensitive to change.

Adult↗
PubMed1992

Use of short-term efficacy/toxicity tradeoffs to select second-line drugs in rheumatoid arthritis. A metaanalysis of published clinical trials.

OBJECTIVE: Preferred drugs for rheumatoid arthritis (RA) should be those that have maximal efficacy with the least toxicity. We evaluated the efficacy and toxicity tradeoffs for drugs frequently used in the treatment of RA. METHODS: We updated 2 metaanalyses of published clinical trials, by adding trials published through 1990 and trials of azathioprine (AZA). We tested 3 different definitions of efficacy, each plotted against 3 different toxicity measures, for antimalarial drugs, methotrexate (MTX), auranofin, injectable gold, D-penicillamine, sulfasalazine (SSZ), AZA, and placebo. Efficacy measures included composite efficacy (a combination of joint count, grip strength, and erythrocyte sedimentation rate), tender joint count alone, and a measure based on how many patients dropped out due to inefficacy. Toxicity measures were the proportion dropping out due to toxicity, the same dropouts with side effects weighted for severity using a modification of a published toxicity index, and the proportion with severe toxicities (defined as a score of at least 7 of 10 on the toxicity index). The latter were usually organ toxicities (e.g., cytopenias and renal involvement). RESULTS: All 9 efficacy/toxicity tradeoff plots suggested that MTX and antimalarial drugs had the highest efficacy relative to toxicity. MTX scored among the most efficacious of the drugs and, of these, had the least toxicity. Antimalarial drugs, though showing only moderate efficacy, had the lowest toxicity rate of all the drugs. SSZ scored close to MTX but was, in general, slightly more toxic. CONCLUSION: In the short-term context of clinical trials, antimalarial drugs and MTX have the best efficacy/toxicity tradeoffs and may, therefore, be the preferred drugs.

Antimalarials↗
PubMed1992

Do self-reported arthritis symptom (RADAR) and health status (AIMS2) data provide duplicative or complementary information?

This study assessed whether self-report measures of symptoms and functional health status provide unique outcome information, or whether functional status assessments primarily serve as a proxy for self-reported arthritis symptoms. Symptom scores of 138 individuals with rheumatoid arthritis (RA) collected with the Rapid Assessment of Disease Activity in Rheumatology (RADAR) measure were compared with same-day functional health scores collected with the recently revised Arthritis Impact Measurement Scales (AIMS2). Correlational and factor analyses revealed that self-assessed arthritis symptoms, physical function and work impact, psychological status, and social health each made independent contributions to outcome. Satisfaction with health status was shown not to be independent of symptoms, functional capacity, or psychological status. It is important to document that self-reported symptom and health status information, when collected concurrently, provides complementary rather than duplicative information.

Activities of Daily Living↗
PubMed1992

Bone mineral density in elderly men and women: results from the Framingham osteoporosis study.

Our study investigated bone mineral density of the proximal femur and ultradistal and proximal radius in a population of elderly men and women. The Framingham study started in 1948, following a population-based sample for evaluation of cardiovascular risk factors and events. During the 20th biennial Framingham examination (1988-89) we conducted the Framingham osteoporosis study, measuring bone mineral density in the proximal femur and distal and proximal radius for 1154 study participants. Ages ranged from 68 to 98 years, with a mean age of 76 years. Bone mineral density was measured using Lunar SP2 and DP3 densitometers. This cross-sectional study evaluates mean bone mineral density measurements at each site by 5 year age intervals for men and women, testing for trends in bone density with age. Analyses were repeated adjusting for weight and height. Among the 446 and 708 women, bone mineral density of the femur and bone mineral content of the proximal radius were inversely and significantly related to age in both sexes and were considerably higher in men than women at all sites. The linear decline with age group in our cross-sectional study remained after multivariate adjustment for height and weight. The ultradistal radius showed no significant correlation with age for either sex. There were significant correlations between the bone measurements made at different sites for both men and women (range in r = 0.27-0.89). Cross-sectional curves of bone mineral density with age showed no significant differences in slope between males and females.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1992

Effect of aging and dopaminomimetic therapy on mitochondrial respiratory function in Parkinson's disease.

Oxygen consumption and enzyme activity were evaluated in platelet mitochondria from 17 patients with Parkinson's disease. In comparison with age-matched controls, no consistent abnormality could be discerned in complex I, complex II-III, or complex IV oxygen consumption, or in the enzyme activity of these respiratory chain complexes. Neither chronic therapy with levodopa/carbidopa alone nor in combination with deprenyl significantly affected any measure of mitochondrial respiratory function. There was no discernible relationship between patient age or disease severity and any parameter of mitochondrial respiration. Moreover, blood lactate levels following glucose loading were not different in patients and controls. These results fail to support the occurrence of a generalized defect in any mitochondrial respiratory function in Parkinson's disease.

Age Factors↗
PubMed1992

Are calcium intakes and physical activity patterns during adolescence related to radial bone mass of white college-age females?

The determinants of bone mass, i.e., size and density, in young adult women after cessation of growth in length of the bones are not well understood. Usual dietary calcium (Ca) intakes and physical activity (PA) patterns during the post-pubertal half-decade have been considered as two important factors contributing to bone mass. In the present hypothesis-generating cross-sectional study, radial bone mineral content and density were measured by single-photon absorptiometry at two sites containing different proportions of trabecular and cortical bone tissue in 705 healthy, Caucasian college women (18-22 years). Ca intake during high school and college, as estimated by milk and cheese intake only, was categorized into low, moderate and high groups; and physical activity, estimated during the same time frame, was also categorized into low, moderate and high groups. Bone measurements were related to both long-term dietary Ca intake from milk and cheese and long-term PA in sports, dance or other exercises, as assessed by recall. By univariate analyses, both distal and mid-radial bone mineral content (BMC) and areal bone mineral density (BMD) were found to be positively related to gynecological age (GA) (p less than 0.01). Also, independent effects of long-term Ca intake (p less than 0.05) on distal BMC and BMD, and of long-term PA (p less than 0.05) on distal and mid-BMC and BMD were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

The use of microdialysis for studying the regional effects of pharmacological manipulation on extracellular levels of amino acids--some methodological aspects.

The purpose of this study was to examine and validate the use of microdialysis for sampling and pharmacologically manipulating extracellular amino acids in the brain. Repeated use of microdialysis probes in acute intracerebral experiments did not significantly alter the relative recovery in vitro for the amino acids quantitated (GABA, aspartate, glutamate, glycine, taurine, and alanine). Regional differences in basal levels of some of the amino acids were detected in dialysates collected from the dorsomedial hypothalamus, striatum, and frontal cortex. The percent in vitro recoveries for the amino acids from the probes used in the three regions were not significantly different suggesting that the regional differences in basal levels of amino acids were functionally derived and not a consequence of variations in probe recovery. Perfusion with nipecotic acid, an inhibitor of GABA uptake, resulted in selective elevations in extracellular GABA in the three regions studied. Conversely, perfusion with high-potassium, a depolarizing agent, resulted in significant elevations in not only extracellular GABA but also aspartate, glutamate, and taurine. Thus, microdialysis is a method which can be employed to assess and to pharmacologically manipulate extracellular amino acids in the rat brain.

Amino Acids↗
PubMed1992

Educational attainment and osteoarthritis: differential associations with radiographic changes and symptom reporting.

Educational attainment has been negatively associated with the prevalence, morbidity and mortality of many diseases. With knee osteoarthritis as an example, we used NHANES I data to examine whether the cross-sectional association between formal education and disease is due to known risk factors, and also whether educational attainment is more strongly associated with self-reported symptoms or with radiographic change. We found univariate associations between osteoarthritis and low levels of education. For radiographic knee osteoarthritis in women, and in both sexes combined, this relationship was explained by controlling for known risk factors, which included age, knee injury, race, obesity, and occupation. However, even after adjusting for these major risk factors and the presence of radiographic changes, reporting of knee pain and arthritis at any site remained significantly associated with low educational attainment, especially for those with less than or equal to 8 years of education.

Adult↗
PubMed1991

Identification and characterization of the ribosomal RNA-encoding genes in Clavibacter xyli subsp. cynodontis.

Clavibacter xyli subsp. cynodontis (Cxc) is a xylem-inhabiting bacterial endophyte of Bermudagrass. This organism is classified with Gram-positive, high G + C content, coryneform-actinomycete bacteria. Southern-blot analysis showed that Cxc contains only one copy of the ribosomal RNA-encoding genes (rRNA). A clone containing the rRNA genes was isolated from a genomic library of Cxc DNA cloned in the lambda EMBL3 vector. The gene cluster was partially sequenced, revealing the gene order 5'-16S-23S-5S-3', similar to that found in other prokaryotes. Low-resolution S1 mapping suggested multiple transcription start points of the rRNA operon.

Actinomycetales↗
PubMed1991

Thiazide diuretics and the risk of hip fracture. Results from the Framingham Study.

Thiazide diuretics may preserve bone mass and prevent elderly women's osteopenic fractures, but studies have not distinguished between thiazide preparations or examined former users. We performed a case-control study looking at thiazide use and subsequent hip fracture in postmenopausal female members of the Framingham Study cohort. Cases who had experienced a first hip fracture (n = 176) were compared with age-matched controls (n = 672). Results showed a modest protective effect of any recent thiazide use (not significant). However, recent pure thiazide users experienced significant protection against fracture (adjusted odds ratio, 0.31; 95% confidence interval, 0.11 to 0.88), whereas recent users of combination drugs containing thiazides experienced no protection (adjusted odds ratio, 1.16; 95% confidence interval, 0.44 to 3.05). Combination drugs generally contained only 25 mg of hydrochlorothiazide, suggesting that the small amount of thiazide was insufficient to preserve bone mass. Former thiazide users were not protected against fracture. In sum, recent pure thiazide use in women protects against hip fracture.

Aged↗