Biomedical subjects

N Kogan

Publications and source records attributed to N Kogan.

16 recordsLinked to original sources

PubMed1992

Gender influences on age cognitions and preferences: sociocultural or sociobiological?

The present article reviews research concerned with gender effects on cognitions and evaluations of people varying in age. Sontag's (1979) article on the double standard of aging--the purportedly more negative consequences of aging in women in contrast to men--serves as a point of departure for the review. Research using attitude-scale, semantic differential, and person-perception methodology points to sex-of-target, sex-of-subject, and target-subject interaction effects in response to a diversity of age-relevant stimuli. Though the reported studies are not completely consistent, there is much suggestive evidence that age is a more salient dimension for men than for women when judging others. Furthermore, men exhibit a stronger youth bias. The overall evidence is consistent with an evolutionary hypothesis, but further research that focuses on the proximal determinants of the observed effects is urged.

Aged↗

PubMed1991

Plasmodium falciparum: evidence for a DNA methylation pattern.

The methylation status of the adenine and cytosine residues in the genome of Plasmodium falciparum was studied using restriction enzymes exhibiting differential activity dependent on the methylation state of these residues in their recognition site. The gene coding for the enzyme dihydrofolate reductase-thymidylate synthase was studied for that purpose. No methylated adenine residues were observed in this gene in four strains tested. However, partial methylation of cytosine residues was observed in all strains. This methylation occurred at a specific site of the gene and was of the eukaryotic type, namely at a CpG sequence.

5-Methylcytosine↗

PubMed1988

The calcium channel blocker nisoldipine delays progression of chronic renal failure in humans (preliminary communication).

Chronic renal failure (CRF) patients with a stable course were asked to participate in a follow-up program in which they were randomized into two groups: 1) the placebo group taking their standard antihypertensive therapy without any calcium ion blocker: and 2) the nisoldipine group, those patients taking the calcium channel blocker nisoldipine as the only antihypertensive drug. The two groups had similar blood pressures on entering the study (151 +/- 21.3/90.7 +/- 7.4 mmHg in the nisoldipine and 146.7 +/- 18/94 +/- 9.4 mmHg in the placebo group). Their protein intake was also similar (daily average throughout the follow-up period: 0.83 +/- 0.18 g protein per kg body weight in the nisoldipine and 0.9 +/- 0.12 g in the placebo group). The patients were checked monthly. The follow-up averaged 11.1 +/- 4.8 months in the nisoldipine group and 13.7 +/- 4.2 months in the placebo group. The rate of progression of CRF, as expressed by the slope of the regression line of 1/serum creatinine versus time, decreased in the nisoldipine group from the initial (-8.03 +/- 4.91) x 10(-3) to (-5.57 +/- 5) x 10(-3) (two-tailed P-test = 0.016) after intervention. The slopes tended to become steeper in the placebo group, with an initial slope of (-4.1 +/- 3.2) x 10(-3) changing to (-7.9 +/- 5) x 10(-3) after intervention. This difference did not reach statistical significance (two-tailed P = 0.072). The rate of progression of CRF decreased in 12 of 14 patients in the nisoldipine-treated group versus 3 of 11 patients in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Effect of the calcium channel blocker nisoldipine on the progression of chronic renal failure in man.

Patients with stable renal insufficiency were randomized into two groups: (1) patients given the channel blocker nisoldipine (n = 17) and (2) placebo-treated patients (n = 17) also taking their regular antihypertensive therapy which did not include calcium blockers. Patients were already on low protein diet with a protein intake of 0.80 +/- 0.2 in the nisoldipine group versus 0.85 +/- 0.25 g/kg body weight in the placebo-treated group. The monthly progression of their renal failure was assessed by the reciprocal of serum creatinine versus time in months. After a mean follow-up of 17.4 +/- 8.2 (range 6-30) months, the nisoldipine-treated group had a significant decrease in their slope of progression, whereas the placebo-treated patients, after 16.94 +/- 7.2 (range 6-30) months of follow-up, had no significant change in their slope. The protein intake during follow-up was similar, being 0.85 +/- 0.2 g/kg actual body weight in the nisoldipine-treated group and 0.88 +/- 0.26 g/kg in the placebo group. The changes in slope did not correlate with the changes in blood pressure.

Adult↗

PubMed1980

Understanding visual metaphor: developmental and individual differences.

The development of an instrument--the Metaphoric Triads Task (MTT)--for the assessment of metaphoric comprehension is described. In the tradition of earlier cognitive-style research, a visual triad format was adopted that offered three possible pairings of pictorial stimuli, one of which was metaphorical in character. A subject's score reflects the number of metaphoric pairings formed (with appropriate metaphoric explanations) across all of the triads of the task. Data are reported for 12 samples of subjects (ranging from 7 1/2 to 28 years of age) who responded to the MTT in a diverse array of studies. Internal analyses of the MTT yielded satisfactory reliabilities (interjudge and internal consistency) and item-sum correlations. Sex differences were negligible, but progressive improvement in MTT score with age was noted. At the same time, a slight modification of the MTT triad format generated performance levels from younger children that approximated those of children 1--3 years older who had taken the MTT in its standard form. Higher MTT scores were generally obtained by those subjects who attempted more pairings, spent more time at the task, and chose the metaphoric pair as "best" among the alternative pairing possibilities. Correlations of MTT performance with standardized tests of intellective aptitudes and achievements were inconsistent across samples and between the sexes within samples. In contrast, MTT scores were quite consistently related to solving difficult analogies, generating high-quality responses to divergent-thinking tasks, and manifesting broad categorizing and physiognomic sensitivity. Significant correlations between the MTT and a set of verbal metaphoric triads offered convergent validational evidence suggestive of a general metaphoric style. Some relation was found between MTT performance and teacher ratings of figurative language appreciation and esthetic sensitivity, though it appeared that these might be mediated by the teachers' estimate of the child's overall capability. Finally, three experimental training studies were carried out. A requirement of exhaustive pairing and informative feedback on pretest items significantly enhanced the MTT performance of the younger children. The provision of appropriate verbal labels for each picture in a triad also significantly enhanced performance by insuring that children's encoding of the pictures was consistent with the metaphoric linkage in each item.

Adolescent↗

PubMed1979

A study of age categorization.

This study used photo (stimulus persons) to explore age categorization in a sample of 150 subjects of diverse ages: 15 males and 15 females in each of five age groups: 18--21, 22--28, 29--38, 39--55, and 56--76. Two sets of 33 photos each (a male and a female set) were presented to subjects for chronological age estimation, age categorization (as adolescent, young, middle-aged, elderly, and aged adult), and preference. Results indicated considerable overlapping of estimated ages across age categories, suggesting that the boundaries between adjacent age stages are highly permeable. Sex-of-photo exerted a major influence on categorization and preference. Female, relative to male, stimulus persons were assigned to older age categories, were perceived to attain middle-aged and elderly status sooner, and were younger when chosen as most preferred (but only for male subjects). These sex-bias effects were mitigated in the oldest respondent. Relevance of the present research to problems of age stereotyping is discussed.

Adolescent↗

PubMed1974