Biomedical subjects

C A Johnson

Publications and source records attributed to C A Johnson.

At least 271 records · Page 15Linked to original sources

PubMed1990

Relative effectiveness of comprehensive community programming for drug abuse prevention with high-risk and low-risk adolescents.

This article reviews major risk factors for cigarette smoking, alcohol, and other drug abuse and promising community-based approaches to primary prevention. In a longitudinal experimental study, 8 representative Kansas City communities were assigned randomly to program (school, parent, mass media, and community organization) and control (mass media and community organization only) conditions. Programs were delivered at either 6th or 7th grade, and panels were followed through Grade 9 or 10. The primary findings were (a) significant reductions at 3 years in tobacco and marijuana use and (b) equivalent reductions for youth at different levels of risk. This study provides evidence that a comprehensive community program-based approach can prevent the onset of substance abuse and that the benefits are experienced equally by youth at high and low risk.

Adolescent↗

PubMed1990

Perceived barriers to exercise and weight control practices in community women.

A sample of community women was surveyed to determine exercise habits, weight control methods, and perceived barriers to sustaining and initiating exercise and weight management programs. Lack of time was reported to be the most significant factor limiting exercise, while lack of willpower and time constraints were the most frequently reported obstacles to weight management. Suggestions to aid adherence to exercise and weight control programs among women are outlined.

Adolescent↗

PubMed1990

Ampicillin and sulbactam pharmacokinetics and pharmacodynamics in continuous ambulatory peritoneal dialysis (CAPD).

The fixed combination antibiotic ampicillin/sulbactam may provide a new, safe, and effective method of treating dialysis-related bacterial peritonitis. The pharmacokinetics of this antibiotic combination were determined in patients receiving continuous ambulatory peritoneal dialysis (CAPD). The pharmacodynamic activity of this drug was also determined by use of mean bactericidal titers against selected bacterial strains. Six noninfected CAPD patients in a randomized two-way crossover study were given a fixed dose of ampicillin (2 gm) and sulbactam (1 gm) either intravenously or intraperitoneally. The mean peak ampicillin and sulbactam serum concentrations following intravenous dosing were 170.3 and 87.5 micrograms/mL, respectively. The mean peak serum concentrations of ampicillin and sulbactam following intraperitoneal dosing were 48.0 and 27.8 micrograms/mL, respectively. Absolute bioavailabilities of the intraperitoneal ampicillin and sulbactam doses were 60% and 68%. Both drugs exhibited similar distribution and elimination characteristics. Renal failure markedly reduced drug elimination. Intraperitoneal administration of ampicillin/sulbactam provided satisfactory inhibitory and bactericidal antibiotic titers for most organisms in dialysate at 6 h but not 24 h. Ampicillin/sulbactam (2 gm/1 gm) should be administered every 12 h to patients with peritoneal dialysis-related peritonitis.

Adult↗

PubMed1990

Ascariasis.

Ascaris lumbricoides is the most common helminth to infect humans. Infection occurs when contaminated soil containing mature eggs is swallowed. Clinically, infection ranges from the asymptomatic carrier state to life-threatening pulmonary disease or intestinal obstruction. Diagnosis is most frequently established by identification of the eggs in stool specimens. Treatment with antiparasitic drugs is effective in preventing serious complications and eradicating the parasite from all members of the household.

Anthelmintics↗

PubMed1990

Short-term fluctuation as an estimate of variability in visual field data.

The short-term fluctuation index (SF) is one of several values that provide an indication of a patient's response reliability during an automated perimetry examination. The authors investigated the number of visual field locations used and the number of determinations per location as factors affecting the SF estimate. A computer simulation program for perimetry was used to measure the SF index for 350 normal visual fields with various levels of response fluctuation. As expected, the variability of the SF estimate decreased as the number of locations used to estimate SF increased. There was a more important finding that, for an equal number of threshold estimates, a larger number of determinations at a smaller number of locations produced greater consistency in the SF estimate (eg, ten determinations at two locations instead of two determinations at ten locations). However, it is also important to sample from a representative spatial distribution of visual field locations. These results suggest that five determinations at four locations in the visual field is optimal for most clinical perimetric testing situations.

Computer Simulation↗

PubMed1990

Deferoxamine for aluminum toxicity in dialysis patients.

Aluminum toxicity, prevalent among individuals with chronic renal failure, is associated with disabling osteomalacia, encephalopathy, and anemia. The control of aluminum intake has included standards to limit the amount of aluminum in the dialysis fluid in addition to the use of nonaluminum containing phosphate binders. Deferoxamine mesylate, a heavy metal chelating agent, is used to remove aluminum from the tissues of dialysis patients. Chelation therapy has resulted in improvements of clinical symptoms and bone histology. Ocular, auditory, and infectious adverse effects have occurred with the use of deferoxamine. Future studies are needed to determine the most effective method of removing the aluminum-deferoxamine complex.

Aluminum↗

PubMed1990

Characteristics of eighth-grade students who initiate self-care in elementary and junior high school.

The purpose of this paper is to examine whether children who care for themselves for longer periods of time are at increased risk of poor grades, truancy, anger, family conflict, stress, risk-taking, and peer influences (in addition to the increased risk of substance use previously reported). Demographic characteristics of eighth-grade students who initiate self-care in junior high school are compared with those initiating self-care in elementary school. Further, increased risks for those initiating self-care in elementary school are examined. Over two thirds of the respondents (67.8%) cared for themselves after school without adult supervision at some time during the week; 23.5% for 1 to 4 hours per week, 15.7% for 5 to 10 hours per week, and 28.6% for 11 or more hours per week. Of those in self-care, 48.5% initiated self-care during elementary school and 51.5% during junior high school. Students who were in the highest category of self-care (greater than or equal to 11 hours per week) vs those in self-care zero hours per week were 1.5 to 2 times as likely to score high on risk-taking, anger, family conflict, and stress, to be more likely to see their friends as their major source of influence, and to attend more parties. The self-reports of academic grades did not differ. The grade of initiation of self-care (elementary vs junior high school) conferred additional risk for drinking alcohol (odds ratio = 1.4), risk-taking tendencies (odds ratio = 1.5), and attending parties (odds ratio = 1.6).

Adolescent↗

PubMed1989

Visual field damage in normal-tension and high-tension glaucoma.

We studied the ocular characteristics of 40 pairs of normal-tension and high-tension glaucoma patients who matched closely for the extent of field damage, pupil size, and visual acuity. To determine if there were differences in visual field damage between patients with normal-tension and high-tension glaucoma, we studied characteristics of the areas of the patients' visual fields that were undisturbed. We computed the number of normal locations, the number of clustered normal locations, and the size of the largest cluster of normal locations. The results showed that for an equivalent extent of damage, the individuals in the normal-tension group had greater areas with normal sensitivity, hence more localized damage. A comparison of the patient data to control data showed that paired differences were larger when the normal-tension member of a pair had a larger value in any of the parameters. The results support the hypothesis that glaucoma patients with lower intraocular pressures have more localized damage and those with higher intraocular pressures have more diffuse damage.

Female↗

PubMed1989

A multicommunity trial for primary prevention of adolescent drug abuse. Effects on drug use prevalence.

The entire early adolescent population of the 15 communities that constitute the Kansas City (Kansas and Missouri) metropolitan area has participated in a community-based program for prevention of drug abuse since September 1984. The Kansas City area is the first of two major metropolitan sites being evaluated in the Midwestern Prevention Project, a longitudinal trial for primary prevention of cigarette, alcohol, and marijuana use in adolescents. The project includes mass media programming, a school-based educational program for youths, parent education and organization, community organization, and health policy components that are introduced sequentially into communities during a 6-year period. Effects of the program are determined through annual assessments of adolescent drug use in schools that are assigned to immediate intervention or delayed intervention control conditions. In the first 2 years of the project, 22,500 sixth- and seventh-grade adolescents received the school-based educational program component, with parental involvement in homework and mass media coverage. Analyses of 42 schools indicate that the prevalence rates of use for all three drugs are significantly lower at 1-year follow-up in the intervention condition relative to the delayed intervention condition, with or without controlling for race, grade, socioeconomic status, and urbanicity (17% vs 24% for cigarette smoking, 11% vs 16% for alcohol use, and 7% vs 10% for marijuana use in the last month), and the net increase in drug use prevalence among intervention schools is half that of delayed intervention schools.

Adolescent↗

PubMed1989

Response properties of normal observers and patients during automated perimetry.

Automated perimetry was performed on both eyes of 54 normal subjects, 36 patients with ocular hypertension and normal visual fields, and 20 patients with early glaucomatous visual field loss to evaluate false-positive errors, false-negative errors, fixation losses, consistency of double determinations, and testing time. For all subject groups and response measures, large interindividual variation was found. No meaningful age-related changes were obtained for false-negative errors, false-positive errors, fixation losses, or consistency of double determinations. Contrary to earlier reports, we found a low number of normal subjects and patients exceeding the 33% false-positive and false-negative limits established for the Humphrey Field Analyzer. A large number of normal subjects and patients, however, exceeded the 20% limits for fixation losses.

Adult↗

PubMed1989

The television, school, and family project. V. The impact of curriculum delivery format on program acceptance.

Social psychological interventions have been successful in preventing drug and tobacco use in adolescents, but target audience involvement has not been well documented. Examination of program acceptance is necessary to avoid ambiguity when interpreting findings within and across studies. This report presents results from a program acceptance study of a seventh-grade smoking/drug-use prevention and cessation field trial. The research design is an assessment of two experimentally manipulated variations in program delivery on the program acceptance of all provider and target groups involved. Experimental manipulations included classroom and mass broadcast television demonstrations of social resistance skills against pressures to smoke and use drugs. Three aspects of target audience program acceptance were assessed: participation, satisfaction, and perceived program efficacy. Respondents included the target audience (seventh-grade students and parents), instructors, classroom observers, and school administrative staff. Strong main effects of television delivery on student and parent participation were observed. The findings suggest the usefulness of student homework assignment to view television segments with parents at home as a strategy to achieve family involvement in school-based programs. Both television and classroom delivery separately demonstrated significant positive effects on overall program acceptance with moderate interactive effects on perceived program efficacy. While classroom teacher/observers and school administrators reported strong preferences for the experimental (social resistance) classroom curriculum, acceptance of experimental and comparison (information-based) curricula by the student/parent target audience was equivalent.

Curriculum↗

PubMed1989

Longitudinal effects of the midwestern prevention project on regular and experimental smoking in adolescents.

The purpose of this study was to compare longitudinal smoking prevention program effects estimated on a population-based cohort sample of sixth- and seventh-grade students (average n per year = 4,664) using different schools as units of analysis (middle/junior high school as the school of origin or high school as the endpoint school of intervention). Fifty schools in 15 school districts were demographically matched and assigned to either a school and community-based program for prevention of cigarette, alcohol, and marijuana use, or a health education as usual control group. Smoking was measured by questionnaires administered to the students. An expired air (CO) measure of smoking was also administered to increase accuracy of self-reports. Program effects were estimated with regression analyses, controlling for school-level socioeconomic status, racial/ethnic make-up, urbanicity, and grade. Using school of origin as the unit of analysis, program effects showed 1 year net reductions of -8, -6, and -5% in prevalence rates of smoking in the last month, last week, and last 24 hr; 2-year program effects showed similar net reductions of -6, -5, and -3% (P's less than 0.10-0.001). Analyses with endpoint school as the unit showed slightly weaker effects at the 2-year follow-up, the year during which 64% of students had moved to a junior high or high school. The findings are discussed in terms of the potential contamination of experimental groups in longitudinal studies from school consolidations, family mobility, and feeder patterns to high schools, and the different smoking environments represented by middle, junior high, and high schools.

Adolescent↗

PubMed1989

The television, school and family smoking prevention/cessation project. IV. Controlling for program success expectancies across experimental and control conditions.

A major issue in smoking prevention research is that no study has tried to equate program success expectancies across experimental and placebo control conditions. Equivalent overall program success expectancies should be established to help rule out the effects of extra-theoretical variables which influence program outcomes. The present study tested whether an attention-placebo (information based) smoking prevention program would produce equivalent expectancies about the likelihood of program success in comparison to an experimental social influences program. To try to equate program success expectancies, the design of the two programs differed in content but was similar in procedure. Fourteen middle schools were randomly assigned to the two conditions. As hypothesized, baseline expectancies were found to predict outcome measures, even after controlling for baseline smoking intentions, ethnic group, and gender. Second, the equivalence of program expectancies at posttest was tested. Youths held equivalent overall expectancies for success across conditions. This study suggested the need to control for program expectancies in prevention research, and showed that program expectancies could be controlled for by equating process of program delivery.

Adolescent↗

PubMed1989

Evidence for two paths of alcohol use onset in adolescents.

Research is needed to identify risk factors specifically associated with the development of substance abuse. The current study explored the possibility that adolescents classified as having a problem behavior prone orientation (Type II) are predisposed to more rapid alcohol use onset compared to more normally socialized (Type I) adolescents. It was hypothesized that both types of adolescents would increase their alcohol use over time, but that problem behavior prone adolescents would increase their rates of alcohol consumption more rapidly than would normally socialized adolescents. Using ANCOVA (with baseline alcohol use as a covariate) and t tests (examining only nondrinkers at baseline), the hypotheses were strongly supported. Both Type I and Type II adolescents significantly increased their alcohol use over a one-year period. Type II adolescents, in comparison to Type I adolescents, had significantly higher alcohol use. The greater alcohol use among Type II adolescents was attributed to their problem behavior prone orientation. The findings suggest the existence of two different developmental pathways of alcohol use onset, one initiated by normally socialized adolescents and the other by adolescents with a problem behavior prone orientation. Future alcohol abuse prevention programs may benefit from tailored intervention strategies which take into account population specific risk factors.

Adolescent↗

PubMed1989

Joiners and non-joiners in worksite smoking treatment: pretreatment smoking, smoking by significant others, and expectation to quit as predictors.

Treatment joiners were differentiated from non-joiners when examined across six worksite clinic locations in the Los Angeles area. Predictors examined included preprogram smoking, demographic variables, smoking by significant others, behavioral expectations to quit, and self-efficacy regarding completing treatment and resisting urges to smoke. Non-joiners reported higher preprogram smoking levels and more friends and children who smoked.

Adult↗

PubMed1989

Visual field loss in migraine.

Ocular symptoms are a common, though transient, initial component of migraine. Although permanent visual loss has been reported in a limited number of patients, detailed evaluations of the visual field using current techniques have not been conducted. This study examined the prevalence of visual field loss in patients with migraine, using an automated static perimeter. All patients had at least a 2-year history of migraine (as diagnosed by a neurologist) and no ocular problems (by history or as determined by a visual screening examination consisting of acuity, intraocular pressure [IOP], and evaluation of the disc). The authors' results for 60 migraine patients showed that 21 (35%) had some form of visual field abnormality (P less than 0.05). The prevalence of visual field loss was greater with increasing age and duration of disease. These results suggest that visual field loss from migraine may be more common than previously considered. This information also may be useful in elucidating the relationship between migraine and certain vascular conditions of the eye.

Adolescent↗

PubMed1989

Primary prevention of chronic diseases in adolescence: effects of the Midwestern Prevention Project on tobacco use.

This article reports six-month, one-year, and two-year effects of a longitudinal multicomponent community program directed toward delaying the onset of cigarette smoking in adolescence. Results are based on a longitudinal panel of sixth and seventh grade students from eight schools in the Kansas City Standard Metropolitan Statistical Area (n = 1,122). In the fall of 1984, schools were assigned to either a program group, which received school, booster, parent, and mass media program components, or a control group that received regular health education programming in school and mass media exposure. By six months, there was a significant effect of the program on recent smoking, with the prevalence of smokers in the program group increasing more slowly than in the control group. At two years, 19% of students in the program group reported smoking in the last month versus 29% of students in the control group; and 12% versus 19%, respectively, reported smoking in the last week. The lifetime prevalence rate showed a marginal program effect at two years, with 57% of students in the program group having smoked once or more compared with 65% in the control group. The program was also effective across different levels of cigarette use ranging from no current use to use of one pack or more per day at two years.

Adolescent↗

PubMed1989

Estimating intervention effects in longitudinal studies.

Longitudinal studies aimed at assessing the impact of interventions on disease risk factors often confront several statistical problems. These problems include 1) dependent variables measured by ordered categories, 2) numerous potentially relevant patterns of transition between outcome levels, 3) mixed units of analysis (e.g., assignment by social unit while theorizing in terms of individuals), 4) incomplete randomization, and 5) correlated estimates for successive occasions of longitudinal measurement. Longitudinal data on use of cigarettes, alcohol, and marijuana among adolescents (n = 1,244, complete data) from the Midwestern Prevention Project are used to demonstrate solutions to each of these problems: 1) a proportional odds regression model, 2) conditional logistic models of transitions with interactions between baseline level and intervention effect, 3) a logistic model estimated with linear regression methods on measures aggregated by social unit, 4) conditional and unconditional models of effect magnitude, and 5) a repeated measures logistic regression technique. Panel data fit to the various models yielded the following conclusions concerning intervention effects in the Midwestern Prevention Project: reduction in the prevalence of cigarette users in treatment schools compared with control schools (8% vs. 18% smoked in the last week at one year follow-up), mixed evidence of an effect on marijuana use, and no evidence of an effect on alcohol use.

Adolescent↗