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Biomedical subjects

S M Johnson

Publications and source records attributed to S M Johnson.

230 records · Page 13Linked to original sources
PubMed1972

Self-regulation in the modification of disruptive classroom behavior.

This study compared self-regulation and external regulation procedures in the treatment of children's disruptive classroom behavior. After baseline data were collected, three of the four most disruptive children in each of 10 first- and second-grade classrooms received reinforcement for achieving low rates of disruptive behavior. The fourth child served as a control subject throughout the experiment. Two of the three experimental subjects were then taught to self-observe their own disruptive behavior. In the final reinforcement period, these subjects were given control over dispensing reinforcers to themselves, based on their self-collected behavioral data while subjects in the other experimental group continued with the externally managed reinforcement. In extinction, reinforcement was discontinued for all subjects, but one of the self-regulation subjects in each classroom continued overtly to self-observe. Results indicated that both reinforcement programs reduced disruptive behavior. The self-regulation procedures were slightly more effective in reducing disruptiveness than was the external regulation procedure, and this advantage persisted into extinction. These results suggest that self-regulation procedures provide a practical, inexpensive, and powerful alternative in dealing with disruptive behavior in children.

Journal Article↗
PubMedDate not supplied

Exposure to environmental tobacco smoke--perceptions of African American children and adolescents.

BACKGROUND: A study was designed to investigate the knowledge, attitudes, and preventive efforts with regard to exposure to environmental tobacco smoke (ETS) among a sample of urban African American children and adolescents. METHODS: A sample of 675 students enrolled in grades 5 through 12 in an urban public school district located in the greater metropolitan area of Detroit, Michigan, was surveyed. RESULTS: Smoking rates among students were higher if someone else in the home was a smoker and lower if there were no other smokers in the home. Forty-eight percent of the students reported that their fathers smoked, while 46% reported mothers who smoked. In each of the areas knowledge, attitudes, and preventive efforts, elementary students scored highest and middle school students scored lowest. Attitude scores were higher if the mother or father was a nonsmoker, and nonsmokers scored higher than smokers on knowledge, attitudes, and preventive efforts. Students' preventive efforts were significantly predicted by their knowledge, attitudes, and gender, while their attitudes were in turn predicted by their knowledge, gender, school level, and smoking status and by the proportion of their friends who were smokers. Students' knowledge was significantly predicted by their gender and school level and by the proportion of their siblings who were smokers. CONCLUSIONS: It is apparent that many of the African American students surveyed in this study experience significant exposure to ETS, particularly in the home. As is evident from the literature, this has implications for the long term health of these youngsters. Health education and promotion efforts should be directed not only toward the students themselves, but should also address the smoking behavior of parents and others in the home environment.

Adolescent↗
PubMedDate not supplied

Opioid dependence in myenteric neurons innervating the circular muscle of guinea-pig ileum.

Guinea-pigs were treated with morphine for 6-8 days by subcutaneous implantation of pellets, each containing a mixture of morphine base (120 mg) and morphine hydrochloride (35 mg). Each guinea-pig received a single pellet. Mechanical activity of the circular muscle was recorded in vitro in preparations comprising the circular muscle and myenteric plexus. Exposure to morphine was maintained by addition of 1 microM morphine to the organ baths. After 90 min, morphine was withdrawn, either by repeatedly washing tissues in morphine-free Krebs' solution, or by addition of naloxone to reduce the occupancy of the opioid receptors by morphine. Withdrawal of morphine resulted in markedly enhanced contractile activity compared with that in circular muscle-myenteric plexus preparations from untreated control guinea-pigs. The withdrawal contractions were abolished by tetrodotoxin (600 nM) and greatly reduced by hyoscine (1 microM), indicating that they resulted from action potential discharge in myenteric neurons that release acetylcholine onto the circular muscle. Activation of the cholinergic excitatory motor neurons was not secondary to synaptic activation by cholinergic interneurons, because hexamethonium (100 microM) did not affect withdrawal contractions. The withdrawal response may therefore arise in the cholinergic excitatory motor neurons themselves, or in neurons that activate them via noncholinergic mechanisms.

Animals↗
PubMedDate not supplied

Management of glaucoma in pregnancy and lactation.

A 30-year-old pregnant woman with glaucoma is presented. The management of her case is used as a basis for a discussion of the use of glaucoma medications, including newer formulations, during pregnancy and lactation.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

In vitro intestinal processing of prostaglandin F2 alpha in rats: developmental aspects.

Cytoprotective prostaglandins (PGs) such as PGF2 alpha are present in milk and can be absorbed intact from the gastrointestinal tract. Developmental differences in gastrointestinal PG metabolism in vivo have been previously reported. To evaluate the role of small intestinal tissue, detailed analysis of PG processing in vitro of small intestinal segments of suckling and weanling rats using everted sacs was performed. Sacs were incubated in Krebs-Ringer bicarbonate buffer, pH 7.4, at 37 degrees C. Bathing mucosal fluid contained [3H]PGF2 alpha. Proximal and middle intestinal segment everted sacs of suckling rats exhibited greater transfer of radioactivity in comparison with those of weanling rats. Whereas in suckling rats transfer of radioactivity decreased from proximal to distal regions of the intestine, no segmental differences were seen in weanlings. Maturational differences were also present in the capacity for PG catabolism. Suckling rat everted sacs had a greater proportion of radioactivity present as intact, unmetabolized PGF2 alpha present in sac tissue and serosal fluid in all intestinal segments in comparison with those of weanling rats. Weanling everted sacs contained greater amounts of less polar metabolites. These results indicate that there are quantitative and qualitative age-related differences in transfer and processing of exogenous PGF2 alpha in small intestinal tissue of developing rats.

Animals↗
PubMedDate not supplied

Chronic estrogen replacement inhibits aortic intimal hyperplasia independent of serum lipids.

The role of estrogens in providing atheroprotection has been well documented in both epidemiologic and experimental studies. This phenomenon has traditionally been attributed to the beneficial lipid-modifying effects of estrogens. Yet lipid alterations may not be the sole mechanism of estrogen-mediated cardiovascular protection. Previous studies have utilized models of either diet- or injury-induced atherosclerosis. As such, the interrelationship between estrogens, lipids, and atherosclerosis remains unclear. The purpose of this study was to determine the effect of ovariectomy with or without estrogen replacement on the development of aortic intimal hyperplasia. Although we acknowledge the influence of estrogens on the lipid profile, we hypothesized that estrogens are atheroprotective independent of changes in serum lipids. Twelve Warhill ewes (7-11 years old) were randomized to sham (2 sheep) operation, ovariectomy (OVx-5 sheep), or ovariectomy with 17 beta-estradiol replacement (OVxE-5 sheep). Serum cholesterol and triglyceride levels were measured at 0, 6, and 12 months. Necropsy was performed at 6 and 12 months with histologic morphometric analysis of the aortoiliac bifurcation. Ovariectomy resulted in intimal thickening in comparison to the sham (p < 0.0001) and hormone replacement group (p < 0.0001). Serum cholesterol and triglyceride levels were similar and normal (40-60 mg/dl) among all groups. Estradiol abrogates aortic intimal hyperplasia following ovariectomy independent of the hormone's effects on lipid metabolism.

Animals↗
PubMedDate not supplied

Physiological and perceptual features of dysarthria in Moebius syndrome: directions for treatment.

The functioning of the major subsystems of the speech production apparatus of a 12 year old female with Moebius syndrome was investigated using a battery of perceptual and physiological instrumental measures. Perceptual tests administered included: The Assessment of Intelligibility of Dysarthric Speech; the Frenchay Dysarthria Assessment; and a perceptual analysis of a speech sample based on a reading of the Grandfather Passage. Instrumental procedures included: spirometric and kinematic analysis of speech breathing; electroglottographic and aerodynamic evaluation of laryngeal function; nasometric assessment of velopharyngeal function; and evaluation of lip and tongue function using a variety of strain-gauge and pressure transducers. Consistent with the pathophysiological basis of Moebius syndrome, the major dysfunctions of the speech production mechanism were found at the level of the articulatory valve. Somewhat unexpectedly, however, impaired function was also identified at the level of the velopharyngeal and laryngeal valves by both the perceptual and instrumental assessments and at the level of the respiratory system by the physiological analysis alone. The results are discussed with reference to the neurological basis and clinical features of Moebius syndrome. The implications of the findings for the treatment of congenital dysarthria associated with Moebius syndrome are also discussed. The advantage of instrumental analysis over perceptual assessments in defining treatment goals for children with congenital dysarthria is highlighted.

Child↗