Biomedical subjects

C Larochelle

Publications and source records attributed to C Larochelle.

4 recordsLinked to original sources

PubMed1999

Hoxa5 gene regulation: A gradient of binding activity to a brachial spinal cord element.

The Hox genes cooperate in providing positional information needed for spatial and temporal patterning of the vertebrate body axis. However, the biological mechanisms behind spatial Hox expression are largely unknown. In transgenic mice, gene fusions between Hoxa5 (previously called Hox-1.3) 5' flanking regions and the lacZ reporter gene show tissue- and time-specific expression in the brachial spinal cord in day 11-13 embryos. A 604-bp regulatory region with enhancer properties directs this spatially specific expression. Fine-detail mapping of the enhancer has identified several elements involved in region-specific expression, including an element required for expression in the brachial spinal cord. Factors in embryonic day 12.5 nuclear extracts bind this element in electrophoretic mobility shift assays (EMSA) and protect three regions from DNase digestion. All three sites contain an AAATAA sequence and mutations at these sites reduce or abolish binding. Furthermore, this element binds specific individual embryonic proteins on a protein blot. The binding activity appears as a gradient along the anterior-posterior axis with two- to threefold higher levels observed in extracts from anterior regions than from posterior regions. In parallel with the EMSA, the proteins on the protein blot also show reduced binding to probes with mutations at the AAATAA sites. Most importantly, transgenic mice carrying Hoxa5/lacZ fusions with the three AAATAA sites mutated either do not express the transgene or have altered transgene expression. The brachial spinal cord element and its binding proteins are likely to be involved in spatial expression of Hoxa5 during development.

Animals↗

PubMed1999

Multiple cis-acting regulatory regions are required for restricted spatio-temporal Hoxa5 gene expression.

Genetic analyses have revealed the essential role of the murine Hoxa5 gene for the correct specification of the cervical and upper thoracic region of the skeleton, and for the normal organogenesis and function of the respiratory tract, both structures expressing Hoxa5 during embryogenesis. To understand how the expression domains of the Hoxa5 gene are established during development, we have analyzed the cis-acting control regions mediating Hoxa5 gene expression using a transgenic approach. Four transcripts are derived from the Hoxa5 locus. The shortest and most abundant one displays a specific spatio-temporal profile of expression at earlier stages and in more anterior structures along the embryonic axis than the larger forms. We established that an 11.1 kilobase pair (kb) genomic fragment, extending from position -3.8 kb to +7.3 kb relative to Hoxa5 transcription initiation site, was sufficient to reproduce the temporal expression and substantially reconstitute the spatial pattern of the major Hoxa5 transcript. By deletion analyses, we identified a 2.1 kb fragment located downstream of the Hoxa5 gene that possesses mesodermal enhancer activity. Overall, the findings demonstrate that cis-acting regulatory elements essential for the correct expression of the major Hoxa5 transcript are located both upstream and downstream of the Hoxa5 coding sequences.

Animals↗

PubMed1993

[Female student of a visible minority].

This article is the second on visible minority groups in schools of nursing and the profession. The survey was conducted in three institutions in the Ottawa region. The goal was to discover whether statistics reflect the current college and university nursing population. Of this population, 73.7 per cent participated. Results show clearly that the following questions must be answered by health professionals responsible for community services: Is the goal of equal representation of all ethnic groups at the college and university level realistic? How can educators identify reasons why certain ethnic groups lean toward nursing? Will it be necessary to consider several factors in order to clearly identify the visible minority representation? These questions and others will guide the authors in their subsequent surveys of minority representation in the health care professions.

Female↗

PubMed1993

[Ethics: a challenge for education].

Because of new advances in biomedical science and bio-technology, nurses are confronted with dilemmas for which no easy solutions are available. For this reason, it is becoming increasingly crucial that nursing students develop moral judgement. Nursing students find it difficult to relate the principles of ethics (moral conduct, duty and judgment) to concrete nursing situations. Blondeau (1986) believes the case study to be one of the most effective teaching strategies that can be used to raise moral sensitivity. However, it is very difficult to use this strategy with young adult students. The authors believe that if students learn ethical principles prior to the case study they will become aware of ethical problems and will be better prepared to discuss in depth ethical implications. They designed a self-learning module and compared the results with an equivalent group of students. Post-test cognitive results showed a difference between the two groups. Students using the new case study module expressed great satisfaction with the format, utilization and attitudes of this module. The approach proved useful since students were able to learn at their own pace. The time previously used to teach ethical principles was then allotted to class discussions and the process of ethical decision-making.

Education, Nursing↗