Stress-induced Fos-like Immunoreactivity in the Pons and the Medulla Oblongata of Rats

Immunoreactivity of the immediate early gene c-fos was used to investigate changes in the activity of brainstem neurons in response to acute stressors like immobilization, formalin-induced pain, cold exposure, hemorrhage and insulin-induced hypoglycemia. Different stressors induced Fos-like immunoreactivity in different pontine and medullary neurons. A single, 3 hour immobilization was found to be a very strong stimulus that activated brainstem catecholaminergic (tyrosine hydroxylase-immunopositive) neurons and cells in the raphe and certain pontine tegmental nuclei, as well as in the reticular formation. Pain, induced by a subcutaneous injection of formalin was also effective on catecholamine-synthesizing neurons and on others cells in the nucleus of the solitary tract. Cold exposure activated cells mainly in the sensory spinal trigeminal and parabrachial nuclei and in the so-called "pontine thermoregulatory area". Moderate Fos-like immunoreactivity was induced by a hypotonic (25%) hemorrhage in medullary catecholaminergic neurons, the nucleus of the solitary tract and the Barrington nucleus. Among stressful stimuli used, insulin-induced hypoglycemia elicited the smallest Fos activation in the lower brainstem. The present observations indicate that different stressors may use different neuronal pathways in the central organization of the stress response.     

Attitudes of high school students toward carrier screening and prenatal diagnosis of cystic fibrosis

The identification of the common mutations of the cystic fibrosis (CF) transmembrane conductance regulator gene has made it feasible to consider population-based CF carrier screening. However, the demand for such programs will depend largely on the attitudes and perceptions of the general public toward genetic testing. As part of a high school science project, we initiated studies to determine the attitudes of high school students toward carrier screening for CF and other genetic disorders. From a class of 120 biology students, 101 consented to participate in the study. Most of the students were of European ancestry and there were no known family histories of CF. Buccal swabs were obtained for PCR amplification and heteroduplex detection of the most common CF mutation (F508). The students and their corresponding buccal swabs were assigned random numbers and the results were kept confidential unless the student requested his/her test result. A questionnaire was used to assess the students' attitudes toward carrier screening and prenatal diagnosis. This questionnaire was given both before testing and after the class was informed that three individuals were carriers of the F508 mutation. Overall, the data indicate that high school students are receptive to the concepts of carrier screening and prenatal diagnosis. However, their attitudes changed considerably when informed of the possibility that they might actually be a F508 carrier, with marked increases in the level of indecision. At the conclusion of the study, very few students (5/101) requested information about their F508 carrier status.     

Generalist genes and cognitive abilities in Chinese twins

This study considered how far nonverbal cognitive, language and reading abilities are affected by common genetic influences in a sample of 312 typically developing Chinese twin pairs aged from 3 to 11 years. Children were individually given tasks of Chinese word reading, receptive vocabulary, phonological memory, tone awareness, syllable and rhyme awareness, rapid automatized naming, morphological awareness and orthographic skills, and Raven's Colored Progressive Matrices. Factor analyses on the verbal tasks adjusted for age indicated two factors: Language as the first factor and Reading as the second factor. Univariate genetic analyses indicated that genetic influences were substantial for nonverbal cognitive ability and moderate for language and reading. Multivariate genetic analyses showed that nonverbal cognitive ability, language and reading were influenced by shared genetic origins, although there were specific genetic influences on verbal skills that were distinct from those on nonverbal cognitive ability. This study extends the Generalist Genes Hypothesis to Chinese language and reading skills, suggesting that the general effects of genes could be universal across languages.     

Home environmental influences on children's language and reading skills in a genetically sensitive design: Are socioeconomic status and home literacy environment environmental mediators and moderators?

This twin study examined how family socioeconomic status (SES) and home literacy environment (HLE) contributes to Chinese language and reading skills. It included 312 Chinese twin pairs aged 3 to 11. Children were individually administered tasks of Chinese word reading, receptive vocabulary and reading‐related cognitive skills, and nonverbal reasoning ability. Information on home environment was collected through parent‐reported questionnaires. Results showed that SES and HLE mediated shared environmental influences but did not moderate genetic influences on general language and reading abilities. Also, SES and HLE mediated shared environmental contributions to receptive vocabulary and syllable and rhyme awareness, but not orthographic skills. The findings of this study add to past twin studies that focused on alphabetic languages, suggesting that these links could be universal across languages. They also extend existing findings on SES and HLE's contributions to reading‐related cognitive skills.