Biomedical subjects

M C Leung

Publications and source records attributed to M C Leung.

3 recordsLinked to original sources

PubMed1995

A brief method for assessing social development: structure, reliability, stability, and developmental validity of the Interpersonal Competence Scale.

The Interpersonal Competence Scale (ICS-T) is a set of brief rating scales for teachers and parents. It consists of 18 items that assess social and behavioural characteristics of children and youths. The ICS-T yields three primary factors: AGG (argues, trouble at school, fights), POP (popular with boys, popular with girls, lots of friends), and ACA (spelling, math). Subsidiary factors include AFF (smile, friendly), OLY (appearance, sports, wins), and INT (shyness, sad, worry). The psychometric properties of the scale (internal structure, reliability, long-term stability) are presented and evaluated over successive ages. The scale factors have been linked to contemporaneous observations of behavior and social network membership. Developmental validity of the ICS-T includes the significant prediction of later school dropout and teenage parenthood. The ICS-T scale is described, along with instructions for use and scoring.

Adolescent↗

PubMed1995

Friendships and social networks in childhood and adolescence: fluidity, reliability, and interrelations.

Social networks and friendships were tracked over a 3-week period for 132 students enrolled in fourth- and seventh-grade classrooms. Individual interviews were employed to collect data on friendships. Social group membership was determined by the composite social-cognitive map (SCM) procedure and by self-reports. Considerable overlap was found among the methods for establishing relational patterns (i.e., friendships, self-reported groups, composite social-cognitive maps). When loose criteria for stability were employed, high stability was found in friendships (p = .56-.75) and social group membership (p = .90) over a 3-week period. But when stringent criteria were employed, only modest social relationship stability was observed in both methods, suggesting that there is much greater fluidity in peer bonds than has been generally recognized. The relationship between friendship and social network measures, the distinctive information yielded by social networks, and gender and age differences in group structure, fluidity, and friendships are discussed.

Adolescent↗

PubMed1994

NADPH-diaphorase neurons in the retina of the hamster.

NADPH-diaphorase-positive neurons have been demonstrated in the inner nuclear layer and ganglion cell layer of the retina of different mammalian species, but so far no experiments have been conducted to identify whether these cells are amacrine cells and/or retinal ganglion cells. We attempted to solve this problem by studying the NADPH-diaphorase-positive neurons in the hamster retina. From the NADPH-diaphorase histochemical reaction, two distinct types of neurons in the hamster retina were identified. They were named ND(g) and ND(i) cells. The ND(g) cells were cells with larger somata, ranging from 10 to 21 microns in diameter with a mean of 15.58 microns (S.D. = 2.59). They were found in the ganglion cell layer only. The ND(i) cells were smaller, with the somata ranging from 7 to 11 microns and having the mean diameter of 8.77 microns (S.D. = 1.24). Most of the ND(i) cells were found in the inner nuclear layer, and only very few could be observed in the inner plexiform layer. On average, there were 8,033 ND(g) and 5,051 ND(i) cells in the ganglion cell layer and inner nuclear layer, respectively. Two experiments were performed to clarify whether any of the NADPH-diaphorase neurons were retinal ganglion cells. Following unilateral optic nerve section, which leads to the retrograde degeneration of retinal ganglion cells, the numbers of both ND(g) and ND(i) cells did not change significantly for up to 4 months. In addition, when retinal ganglion cells were prelabeled retrogradely (horseradish peroxidase or fluorescent microspheres) and retinas were then stained for NADPH diaphorase, no double-labeled neurons were detected. These results indicated that the NADPH-diaphorase neurons in the hamster retina were the amacrine cells in the inner nuclear layer and displaced amacrine cells in the ganglion cell layer. Dendrites of the ND(g) and ND(i) cells were found to stratify in sublaminae 1, 3, and 5 of the inner plexiform layer, with a prominent staining in the sublamina 5. The possible importance of this arrangement in the rod pathway is also discussed.

Amino Acid Oxidoreductases↗