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Biomedical subjects

C C Johnson

Publications and source records attributed to C C Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Hormone replacement therapy in postmenopausal women: urinary N-telopeptide of type I collagen monitors therapeutic effect and predicts response of bone mineral density.

PURPOSE: To assess the ability of the urinary N-telopeptide of type I collagen (NTx) to monitor and predict therapeutic effects of hormone replacement therapy (HRT) in postmenopausal women. PATIENTS AND METHODS: To assess the relationship between baseline or change in NTx (predictive variable), and change in lumbar and hip bone mineral density (BMD; outcome variable), we conducted a 2-year randomized controlled study at academic university and private practice medical centers in 236 healthy women 1 to 3 years postmenopausal; 227 women completed the study. Women received estrogen plus progesterone plus calcium (treated group) or calcium alone (control group). RESULTS: In the treated group NTx significantly (P < 0.0001) decreased, and spine and hip BMD significantly (P < 0.00001 and P < 0.005, respectively) increased; in the control group NTx did not change but BMD decreased significantly (P < 0.01). Subjects in the highest quartiles for baseline NTx (67 to 188 units) or decreasing NTx (-66% to -87%) through 6 months demonstrated the greatest gain in BMD in response to HRT (P < 0.05 and P < 0.005). For every increase of 30 units in baseline NTx the odds of gain in BMD in response to HRT increased by a factor of 5.0 (95% confidence interval [CI] 1.9 to 13.3); for every 30% decrease in NTx through 6 months, the odds of gaining BMD in response to HRT increased by a factor of 2.6 (95% CI 1.6 to 4.4). In the control group an increase of 30 units in mean NTx across the study indicated a higher odds of losing BMD by a factor of 3.2 (95% CI 1.6 to 6.5). A high baseline NTx (> 67 units) indicated a 17.3 times higher risk of BMD loss if not treated with HRT. CONCLUSION: These data support the clinical utility of NTx to monitor the antiresorptive effect of HRT in recently postmenopausal women, and to predict changes in BMD in response to HRT.

Absorptiometry, Photon↗
PubMed1997

Use of urinary cotinine and questionnaires in the evaluation of infant exposure to tobacco smoke in epidemiologic studies.

Exposure to environmental tobacco smoke is an important variable in many pediatric epidemiologic studies. We measured urinary cotinine, a specific metabolite of nicotine, in a population-based cohort of children every other month from birth through two years of age. Extensive data regarding exposure to smokers (people in the home, in home and away from home day care, home visitors, visits to smokers) were collected monthly by way of home interviews. We evaluated, with multiple cotinine measurements as the gold standard, other measures of exposure that are more feasible to obtain in large-scale studies. Comparing one cotinine to the average of multiple measurements, we found that 33.7% were in error in excess of 100 ng/mg, but 84% of the infants could be correctly classified into categories of low versus high. Parental smoking patterns had the highest predictive accuracy (fathers 67.0% and mothers 64.1%). Combining selected smoker categories (either parent, other home residents outside day care workers) resulted in improved accuracy of 79.3%.

Cotinine↗
PubMed1997

Ethnic differences in the prevalence of asthma in middle class children.

BACKGROUND: Studies have shown a higher prevalence of asthma among boys compared with girls and in blacks compared with whites, but it has been difficult to separate socioeconomic from racial effects because the blacks in the studied populations were more likely to have low socioeconomic status. OBJECTIVE: To compare the prevalence of asthma in a socioeconomically homogeneous, middle class, multiethnic population of schoolchildren. METHODS: Based on a telephone survey of all families of third-graders in Southfield, Michigan, we ascertained the prevalence of physician-diagnosed asthma and probable undiagnosed asthma. One reason Southfield was chosen for study was because the city comprises an integrated middle class population with only 4% blacks and 7% whites having incomes below federal poverty limits. RESULTS: The lifetime prevalence of asthma was 9.5% (12% for blacks and 6% for whites) and higher in boys (14%) than girls (5%), a pattern that was reflected in period prevalence estimates. The lifetime prevalence of probable undiagnosed asthma was greater in blacks (16.6%) than whites (10.8%), with little sex difference. Adjusting for sex and maternal education, the prevalence of physician-diagnosed asthma and probable asthma were associated independently with black ethnicity. CONCLUSIONS: Our study is unique in the similarity of the black and white families' socioeconomic status and residence in the same middle class community. Since access to medical care and macro-environmental conditions were similar across this study population, our results are consistent with the hypothesis that differences in biologic factors between blacks and whites and boys and girls play a role in asthma risk.

Adolescent↗
PubMed1997

The accumulation of whole body skeletal mass in third- and fourth-grade children: effects of age, gender, ethnicity, and body composition.

The purpose of this longitudinal study is to describe bone mass and body composition, and the annual changes in these measurements, among third grade students recruited from a suburban school district. Whole body bone mineral content (WBBMC), bone mineral density (WBBMD), fat, and lean mass were measured by dual-energy X-ray absorptiometry. Bone mass in the lumbar spine (LBMC) region of the whole body scan was also utilized. 773 students (38% white, 57% black, 5% other) had baseline visits; 561 had a second measurement a year later. At baseline, black children have significantly higher WBBMC, WBBMD, height, and lean mass than whites. Black males, but not black females, have a greater LBMC. There are no significant gender differences in body size, WBBMC, or WBBMD, although girls have a greater LBMC and fat mass, and boys have a higher lean mass. Most of these differences persist in visit 2. The annual change in bone and lean mass is greater in blacks. Stepwise linear regression analyses of bone mass on body size, gender, and ethnicity and their interactions indicate that log-transformed weight explains most of the variance in both WBBMC and WBBMD (multiple r2 = 0.90 and 0.64, respectively). There are significant black/white differences in intercepts and slopes. Other variables explain only another 1%-2% of the variance. The strongest Pearson correlations are between changes in bone mass and changes in lean mass and log-transformed weight (r ranging from 0.62 to 0.84, p = 0.0001). We conclude that there is a significant black/white, but not male/female difference in whole body bone mass and bone density before puberty. Ethnic and gender differences in bone and body composition suggest that the lean component may contribute to a greater peak bone mass in blacks vs. whites, and perhaps in males vs. females.

Absorptiometry, Photon↗
PubMed1997

Oropharyngeal candidiasis in patients with AIDS: randomized comparison of fluconazole versus nystatin oral suspensions.

A total of 167 human immunodeficiency virus (HIV)-infected patients with oropharyngeal candidiasis were randomly assigned to receive 14 days of therapy with liquid suspension fluconazole (100 mg once daily) or liquid nystatin (500,000 U four times daily). At day 14, 87% of the fluconazole-treated patients were clinically cured, as opposed to 52% in the nystatin-treated group (P < .001). Fluconazole eradicated Candida organisms from the oral flora in 60%, vs. a 6% eradication rate with nystatin (P < .001). The fluconazole group had fewer relapses noted on day 28 (18%, vs. 44% in the nystatin group; P < .001). This relapse difference no longer existed by day 42. Fluconazole oral suspension as a systemic therapy was more effective than liquid nystatin as a topical therapy in the treatment of oral candidiasis in HIV-infected patients and provided a longer disease-free interval before relapse.

AIDS-Related Opportunistic Infections↗
PubMed1997

Cognitive impairment in the Amish: a four county survey.

BACKGROUND: The prevalence of probable dementia was determined in a rural, homogeneous community of Amish individuals in the Midwestern USA. The Amish are a genetically isolated group with a low level of formal education (< or = 8 years) and few exposures to modern life, who live in intergenerational setting and have strong social support networks. METHODS: Using community directories, trained interviewers administered the Mini Mental State Examination (MMSE) and a medical history survey to all Amish over 64 years old in a four county area. Individuals with scores < 27 (out of a maximum of 30 points) were given additional neuropsychological tests. Results were reviewed by a neuropsychologist and subjects were classified with regard to probable cognitive impairment. RESULTS: The MMSE scores were inversely related with age and directly with education. The Amish have higher MMSE scores than reported for the general US population. The overall prevalence of probable cognitive impairment for those over 64 years was 6.4%. The prevalence increased with age and lower education and was lowest among married individuals. CONCLUSIONS: The MMSE scores among the Amish were higher than the general population despite their low level of formal education. The lower level of cognitive impairment among the Amish could reflect a lack of inherited susceptibility to dementing diseases, or environmental factors characteristic of their traditional lifestyle. Even among this population with < or = 8 years of formal education, education may protect against cognitive impairment.

Age Distribution↗
PubMed1997

Cardiovascular risk factors and behavior lifestyles of young women: implications from findings of the Bogalusa Heart Study.

The primary purposes of this article are to highlight important issues related to cardiovascular risk factors and behavior life-styles in young women and to examine racial (black-white) differences in risk factors that relate to cardiovascular disease. In childhood, some girls show cardiovascular risk factors of higher blood pressure levels, dyslipidemia, and obesity, all of which continue into young adulthood. Factors that contribute to abnormal risk factors are a high-saturated fat diet, excess energy intake related to inactivity, and cigarette smoking. Trends of obesity are documented; and young white girls are continuing to use tobacco, more so than boys and black girls. Although the onset of clinical cardiovascular disease is delayed in women, the stage is set in childhood for the development of early cardiovascular risk.

Adolescent↗
PubMed1997

Occupational exposures to metals as risk factors for Parkinson's disease.

In a population-based case-control study, we investigated the potential role of occupational exposure to iron, copper, manganese, mercury, zinc, and lead as risk factors for Parkinson's disease (PD). Concurrently recruited, nondemented patients (n = 144) with idiopathic PD and controls (n = 464) consisting of men and women > or =50 years of age, frequency-matched for age (within 5 years), race, and sex were enrolled. All had primary medical care at Henry Ford Health System in urban/suburban metropolitan Detroit. Subjects were given an extensive risk-factor questionnaire detailing actual worksite conditions of all jobs held for more than 6 months from age 18 onward. An industrial hygienist, blinded to the case-control status of subjects, rated occupational exposure to each of the metals of interest. When adjusted for sex, race, age, and smoking status, we found in those with more than 20 years' exposure a significantly increased association with PD for copper (OR = 2.49, 95% CI = 1.06, 5.89) and manganese (OR = 10.61, 95% CI = 1.06, 105.83). For more than 20 years' exposure to combinations of lead-copper (OR = 5.24, 95% CI = 1.59, 17.21), lead-iron (OR = 2.83, 95% CI = 1.07, 7.50), and iron-copper (OR = 3.69, 95% CI = 1.40, 9.71), there was a greater association with PD than with any of these metals alone. These findings suggest that chronic exposure to these metals is associated with PD, and that they may act alone or together over time to help produce the disease.

Aged↗
PubMed1997

Cigarette smoking attitudes and first use among third- through sixth-grade students: the Bogalusa Heart Study.

OBJECTIVES: This study examined cigarette smoking attitudes, peer and parental influence, and first use among children in southeastern Louisiana. METHODS: Data from 933 children in grades 3 through 6 in the Bogalusa Heart Study (1993 through 1994) were analyzed. RESULTS: Fifteen percent of the children had tried smoking. Of these, 40% first smoked with a family member, and 46% obtained their first cigarette from a family member or from home. Correlates of ever having smoked were race, sex, having a best friend or family member who smoked, and attitudes that smoking is disgusting and that nonsmokers get better grades. CONCLUSIONS: Prevention programs should begin early and focus on family and peer influences as well as attitudes.

Black or African American↗
PubMed1997

Space Station Biological Research Project.

To meet NASA's objective of using the unique aspects of the space environment to expand fundamental knowledge in the biological sciences, the Space Station Biological Research Project at Ames Research Center is developing, or providing oversight, for two major suites of hardware which will be installed on the International Space Station (ISS). The first, the Gravitational Biology Facility, consists of Habitats to support plants, rodents, cells, aquatic specimens, avian and reptilian eggs, and insects and the Habitat Holding Rack in which to house them at microgravity; the second, the Centrifuge Facility, consists of a 2.5 m diameter centrifuge that will provide acceleration levels between 0.01 g and 2.0 g and a Life Sciences Glovebox. These two facilities will support the conduct of experiments to: 1) investigate the effect of microgravity on living systems; 2) what level of gravity is required to maintain normal form and function, and 3) study the use of artificial gravity as a countermeasure to the deleterious effects of microgravity observed in the crew. Upon completion, the ISS will have three complementary laboratory modules provided by NASA, the European Space Agency and the Japanese space agency, NASDA. Use of all facilities in each of the modules will be available to investigators from participating space agencies. With the advent of the ISS, space-based gravitational biology research will transition from 10-16 day short-duration Space Shuttle flights to 90-day-or-longer ISS increments.

Aerospace Medicine↗
PubMed1997

Racial differences in surgically staged patients with endometrial cancer.

This study examined whether differences in survival for endometrial cancer attributed to race are primarily associated with socioeconomic status, comorbid illnesses, molecular genetic alterations, and other disease-related characteristics identified as poor prognostic factors. One hundred fifty-two surgically staged patients with endometrial cancer (37 African-American and 115 European-American women) treated from 1990 to 1994 were analyzed for differences in demographics, disease-related characteristics, and survival. Survival was poorer for African-American women than for European-American women. African-American women had lower socioeconomic status and a higher prevalence of poor prognostic factors. Surgical stage, positive peritoneal cytology, angiolymphatic invasion, cervical stromal involvement, and a history of other malignancies were similar between the two groups. The most important predictors of survival were age at diagnosis, surgical stage, myometrial invasion, positive peritoneal cytology, cervical stromal involvement, tumor grade, aneuploidy, histology, S-phase fraction, number of poor prognostic factors, and race. Racial differences in survival were not explained by socioeconomic status, comorbid illnesses, or estrogen use. When incorporating the number of poor prognostic factors in a survival model with race and surgical stage, race ceased to be of significant prognostic value. In an analysis restricted to women with poor prognostic factors, this phenomena also occurred after adjusting for the number of poor prognostic factors. These findings suggest that the cumulative number of poor prognostic factors, not race, is a more important predictor of survival in endometrial cancer.

Aged↗
PubMed1997

Anterior cervical fusion using a modified tricortical bone graft: a radiographic analysis of outcome.

A technique was developed to resist graft extrusion by means of mechanical interlocking between graft and vertebrae. A 4-mm burr is used to create a transverse trough (mortise) across the posterior aspect of each endplate. A reversed tricortical graft is shaped to have a ridge (tenon) composed of cortical bone on the upper and lower surfaces of its posterior portion. The ridges lock into the troughs to form a double mortise and tenon joint. Of 117 discs (102 patients) treated, adequate radiographs were available of 106 discs (in 92 patients) of which 89% were fused at last follow-up. Radiographic analysis showed significant (p < 0.001) increases in disc height and extension immediately postoperatively and a return to the preoperative values by the time of fusion. This technique completely eliminated graft extrusion without any reduction in fusion rate compared with most other reported results with the standard tricortical technique.

Adult↗
PubMed1997

Knee kinematics in genesis total knee arthroplasty. A comparison of different tibial designs with and without posterior cruciate substitution in cadaveric specimens.

Knee joint kinematics after total knee arthroplasty (TKA) are not well understood. This study measured knee kinematics before and after TKA in six cadaveric specimens. Different tibial surface contours (standard, flat, and dished) and slopes (10 degrees and 15 degrees) with the posterior cruciate ligament (PCL) intact as well as a posterior-stabilized design were studied. The anteroposterior and proximal-distal displacements of the tibia relative to the femur were measured during active knee extension. For the standard design, it was possible to restore the normal position of the tibia relative to the femur at 90 degrees of flexion to within 2 mm; however, restoration of the tibiofemoral position was not achieved with the knee in the extended position. At 90 degrees of flexion, all of the TKA components resulted in a posteriorly positioned tibia compared with the normal knee. The standard, flat, and dished components shifted the tibia into a proximal position compared with the normal knee, while the 15 degrees and posterior-stabilized components shifted the tibia distally. With the knee in the extended position, the standard, flat, dished, and posterior-stabilized designs placed the tibia posteriorly and proximally compared with the normal position of the tibia relative to the femur. The 10 degrees and 15 degrees sloped components placed the tibia in a more anterior position. Of the PCL-retaining designs tested, the 10 degrees sloped tibial component produced the closest to normal knee kinematics. Overall, normal kinematic behavior of the knee was not restored after TKA.

Aged↗
PubMed1996

Evaluation of factors potentially associated with inadequate follow-up of mammographic abnormalities.

BACKGROUND: To increase the proportion of women who receive the recommended follow-up for mammographic abnormalities, factors which inhibit follow-up must be identified. Patient and health care delivery related factors were evaluated, stratified by type of follow-up recommendation, to determine reasons for inadequate follow-up. METHODS: All Caucasian and African American women at the Henry Ford Medical Group, in southeastern Michigan, with an abnormal screening mammogram result between January 1, 1992 and July 31, 1992 were identified. All women with inadequate follow-up, and a random sample of women with adequate follow-up, were invited to participate in a telephone interview that assessed three major dimensions of the Health Belief Model (susceptibility, benefits, and barriers), general health and health behaviors, and related characteristics. The relationship between these factors and inadequate follow-up was evaluated separately for women with immediate and 6-month follow-up recommendations, using univariate and multivariate analyses. RESULTS: A total of 555 women were invited to participate in the study (219 with inadequate follow-up and 336 with adequate follow-up). Interviews were completed for 418 women (75.3%). Women who were not notified of their mammographic abnormality were excluded from this study, leaving 399 women available for analysis. Among the women who had the recommended immediate follow-up, those who reported difficulty in obtaining medical appointments were 4 times more likely to have inadequate follow-up (95% confidence interval [CI] 1.5, 11.3), after adjusting for other variables. Among the women with six-month follow-up recommended, those who received fewer mammograms in the past 5 years were more likely to have inadequate follow-up (odds ratio [OR] = 4.0; 95% CI 1.6, 10.4). In this group, sociodemographic characteristics were not associated with inadequate follow-up, although women with transportation problems were at a higher risk (crude OR = 5.2; 95% CI 1.6, 16.7; adjusted OR = 3. 1; 95% CI 0.5, 18.3). Among women with 6-month follow-up recommended, those who perceived their health as poor or fair (crude OR = 2.4; 95% CI 1.2, 5.1; adjusted OR = 2.3; 95% CI 0.8, 6.8) and those who did not examine their own breasts frequently (crude OR = 2.3; 95% CI 1.0, 5.4; adjusted OR = 2.7; 95% CI 0.5, 18.3) were also more likely to have inadequate follow-up. CONCLUSIONS: Results from this study demonstrate that the relative importance of factors associated with inadequate follow-up of abnormal mammograms differs according to the type of follow-up recommended. For both types of recommendations, the factors identified are noteworthy because they are amenable to intervention. Efforts should be made to facilitate appointment scheduling for follow-up of abnormal mammograms, and information about previous mammography screening should be obtained to identify women who are at a high risk for inadequate follow-up.

Attitude to Health↗
PubMed1996

Outcomes of a field trial to improve children's dietary patterns and physical activity. The Child and Adolescent Trial for Cardiovascular Health. CATCH collaborative group.

OBJECTIVE: To assess the outcomes of health behavior interventions, focusing on the elementary school environment, classroom curricula, and home programs, for the primary prevention of cardiovascular disease. DESIGN: A randomized, controlled field trial at four sites with 56 intervention and 40 control elementary schools. Outcomes were assessed using prerandomization measures (fall 1991) and follow-up measures (spring 1994). PARTICIPANTS: A total of 5106 initially third-grade students from ethnically diverse backgrounds in public schools located in California, Louisiana, Minnesota, and Texas. INTERVENTION: Twenty-eight schools participated in a third-grade through fifth-grade intervention including school food service modifications, enhanced physical education (PE), and classroom health curricula. Twenty-eight additional schools received these components plus family education. MAIN OUTCOME MEASURES: At the school level, two primary end points were changes in the fat content of food service lunch offerings and the amount of moderate-to-vigorous physical activity in the PE programs. At the level of the individual student, serum cholesterol change was the primary end point and was used for power calculations for the study. Individual level secondary end points included psychological factors, recall measures of eating and physical activity patterns, and other physiologic measures. RESULTS: In intervention school lunches, the percentage of energy intake from fat fell significantly more (from 38.7% to 31.9%) than in control lunches (from 38.9% to 36.2%)(P<.001). The intensity of physical activity in PE classes during the Child and Adolescent Trial for Cardiovascular Health (CATCH) intervention increased significantly in the intervention schools compared with the control schools (P<.02). Self-reported daily energy intake from fat among students in the intervention schools was significantly reduced (from 32.7% to 30.3%) compared with that among students in the control schools (from 32.6% to 32.2%)(P<.001). Intervention students reported significantly more daily vigorous activity than controls (58.6 minutes vs 46.5 minutes; P<.003). Blood pressure, body size, and cholesterol measures did not differ significantly between treatment groups. No evidence of deleterious effects of this intervention on growth or development was observed. CONCLUSION: The CATCH intervention was able to modify the fat content of school lunches, increase moderate-to-vigorous physical activity in PE, and improve eating and physical activity behaviors in children during 3 school years.

Analysis of Variance↗