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Biomedical subjects

C A Johnson

Publications and source records attributed to C A Johnson.

At least 343 records · Page 19Linked to original sources
PubMed1986

High-school smoking prevention: results of a three-year longitudinal study.

This study compared two strategies for preventing cigarette smoking among high-school students. One strategy emphasized social-pressure resistance skills, while the other focused on education about health concerns which are relevant to high-school students. Additionally, the use of same-age peer leaders and the use of familiar models in media presentations were investigated. The results suggest that social-influences resistance training was efficacious in reducing transitions to higher use by those who had previously experimented with cigarettes. Health education was most effective in preventing initial experimentation among those who had not smoked prior to the beginning of the study. Neither program was effective in limiting transitions among those who had gone beyond the experimental stage of smoking, and neither had any effect on encouraging cessation. There were no differences which could be attributed to peer leaders or to familiar media models. During later adolescence, a combined health education and social skills training approach is advocated. It is suggested that while there are some gains by implementing programs during late adolescence, prevention programs targeted at younger students may be more effective generally.

Adolescent↗
PubMed1986

Cardiovascular responsivity to stress: family patterns and the effects of instructions.

Cardiovascular responses to two stressful tasks, as well as to instructions regarding the first task, were assessed in two generations of the same biological family (preadolescent children and their middle-aged parents). Information on the presence of hypertension and other cardiovascular disorders was also obtained for the grandparent generation. Results for the middle-aged normotensive adults confirmed previous observations among young adults of cardiovascular hyperresponsivity among offspring of hypertensive parents; hyperresponsivity was also observed during an instructions period prior to active participation in the task. Personality variables (Type A; hostility) were not related to the observed hyperresponsivity. Assessments of similarity of cardiovascular responses between preadolescent children and their parents were more equivocal; previous studies showing positive results have, for the most part, evaluated children who were somewhat older than those in the present study.

Adult↗
PubMed1986

Win some, lose some: parental hypertension and heart rate change in an incentive versus response cost paradigm.

Fowles (1983), citing evidence from separate studies, suggests that both incentive and response cost paradigms increase heart rate and should be subsumed under Gray's (1975) 'appetitive motivational system'. Shock avoidance and loss of reward (response cost) contingencies, while aversive, appear to evoke this motivational system; consequently both should elicit heart rate increases independent of anxiety. The present investigation compared magnitude of heart rate changes observed under conditions of winning and losing money. Results showed: no differences between incentive and response cost conditions; no effect of state anxiety on heart rate in these conditions, despite an elevation of state anxiety on the task day relative to a subsequent relaxation day assessment; and some evidence for the presence under both such appetitive conditions of cardiovascular hyperresponsivity among offspring of hypertensive parents. The results suggest a need for systematic parametric studies of experimental conditions.

Adult↗
PubMed1986

Purity requirements from a pharmacopoeial point of view.

The nature of pharmacopoeial specifications for bulk drug substances 25-30 years ago and the analytical methods used at that time are briefly reviewed. Since then the concept of characterizing drug substances by controlling impurities has been developed in pharmacopoeias. This concept is examined in relation to: pitfalls in practice; the precision and specificity of analytical procedures; the purity of many drugs nowadays; the usefulness of assays of drug substances; specifications for drug substances for which new methods of synthesis have been used; control of impurities in formulated products; and the significance of purity of drug substances and formulated products.

Journal Article↗
PubMed1986

Variability of quantitative automated perimetry in normal observers.

The test/retest variability in different regions of the visual field were evaluated in six commercially available automated threshold static perimeters using normal volunteers. Three of the devices were projection perimeters (Squid, Octopus 500, Humphrey Field analyzer) and three of them used light-emitting diode stimuli (Dicon 2000, Fieldmaster 50, Digilab 350). The authors' results show that, although some devices were better than others, all have some degree of variability. In addition, they found that there is increased variability from the central 10 degrees out to 30 degrees eccentricity for each perimeter.

Adult↗
PubMed1986

Disorders of pregnancy.

Ectopic pregnancy, uterine torsion, hypocalcemia, and hypoglycemia are discussed. A diagnostic and therapeutic approach to spontaneous abortion and embryonic death is given. Infectious causes of abortion are emphasized. Discussed are the normal variation in gestation length and its relationship to the diagnosis of dystocia as well as the diagnosis and treatment of dystocia.

Abortion, Spontaneous↗
PubMed1986

Motion sensitivity in central and peripheral vision.

The visual resolution of motion is important both for indicating the presence of moving objects and for assisting locomotion and spatial orientation. Additionally, motion may enhance the visibility of low contrast features of the environment. For patients with reduced central vision, these functions may be especially significant as the detection of motion is superior to the ability to resolve stationary detail in peripheral vision. The present paper analyzes the effects of specific stimulus variables on motion sensitivity in both central and peripheral vision. Implications of these findings for low vision patients are discussed.

Humans↗
PubMed1986

Polythelia (supernumerary nipple): an update.

Supernumerary mammary gland, nipple, or areola (with neither nipple nor mammary tissue) have been well documented in the medical literature of the last two decades. Though predominantly a cosmetic blemish, the anomalous appendage may give rise to a neoplasm. Because of its atypical appearance and ectopic location, diagnosis of the anomaly may require a high index of suspicion and histologic verification. In our current concern with breast cancer, there is need to be aware of this entity.

Aged↗
PubMed1986

Balancing program and research integrity in community drug abuse prevention: project STAR approach.

This paper focuses on the process of community-based drug prevention programming using an ongoing, multiple community project (Project STAR) as an illustration. Particular attention is paid to problems and strategies for balancing program and research integrity over the long-term. Specific strategies are discussed for obtaining and sustaining support for the program, quality control throughout program delivery, and accommodation of both research and program objectives.

Adolescent↗
PubMed1986

A scanning and transmission electron microscopic study of rotavirus-induced intestinal lesions in neonatal gnotobiotic dogs.

Neonatal gnotobiotic dogs orally inoculated with canine rotavirus had ultrastructural changes limited to the jejunal and ileal regions of the small intestine. Early scanning electron microscopic findings consisted of swollen villus epithelial cells, denuded foci on intestinal villi, and slight to moderate villus atrophy. Later changes were slight villus atrophy with no denuded intestinal villi. Transmission electron microscopic changes in villus epithelial cells from 12 to 48 hours post-inoculation included: rotavirus particles associated with intracytoplasmic vacuoles near the terminal web and apical tubules; viral particles in dilated cisternae of rough endoplasmic reticulum; and moderate numbers of necrotic cells having no microvilli, swollen mitochondria, membrane-bound lipid-like material in the cytoplasm, clumped chromatin around the periphery of the nucleus, and disruption of the cytoplasmic membrane. In jejunum and ileum at 72 to 154 hours post-inoculation, there were fewer necrotic villus epithelial cells and fewer virus particles. In addition, the ultrastructural morphology of the majority of the villus epithelial cells was similar to crypt epithelium. These studies showed that rotavirus infected the villus epithelial cells with subsequent propagation of the rotavirus and destruction of villus epithelial cells.

Animals↗
PubMed1986

External fixation shoulder arthrodesis.

Shoulder arthrodesis, while providing a useful and predictable solution to many problems associated with glenohumeral degeneration, has been less than desirable for many patients due to the frequent need for postoperative spica cast or airplane splint immobilization. A new technique of external fixation of shoulder fusions has been developed that provides many advantages, including strong, reliable fixation, obviating the need for bulky casts or splints, and immediate postoperative use of the involved arm. This technique of shoulder arthrodesis using the Hoffman external fixation device has been used on four patients, with a follow-up period of 30-36 months. The series includes patients with infected arthroplasty, osteoarthritis, tumor, and previous failed arthrodesis. Bony union was obtained in six to 10 weeks, and the external fixation frame was left in place seven to 14 weeks. In each case, the external fixation frame enabled the patient to use the involved arm immediately after operation.

Adult↗