PubMed Health⌕ Search

Biomedical subjects

A Caswell

Publications and source records attributed to A Caswell.

16 recordsLinked to original sources
PubMed1994

During fetal muscle development, clones of cells contribute to both primary and secondary fibers.

All mammalian muscle fibers are formed by cell fusion, but fiber formation occurs in two successive waves. Initially a small number of large fibers (primaries) are produced and are used as a scaffold for the formation of a larger number of smaller later forming fibers (secondaries). It has been reported that different populations of myoblasts are present at different ages, but it is unclear whether separate populations of cells contribute to primary and secondary fibers during the period of fetal development. We have tested this by injecting two replication-deficient retroviruses, carrying a marker gene (lacZ), into the hind limbs of Embryonic Day (E) 15 and E17 mouse fetuses. All fetuses were killed at E19. Clusters of marked fibers (assumed to correspond to single clones) found after injection at both ages contained both primary and secondary fibers. This indicates that at these ages, a single population of cells contributes to both primary and secondary fibers.

Animals↗
PubMed1993

Effects of cooperative and individualistic learning on prospective elementary teachers' music achievement and attitudes.

The effects of cooperative and individualistic learning on the achievement and attitudes of prospective elementary school teachers (non-music majors) in a course in music teaching methods were examined. Forty-three American college students were randomly assigned to conditions stratified on the basis of previous musical experience. Cooperation promoted higher achievement than did individualistic efforts on assignments for which each student's grade was affected by the quality of groupmates' work. In addition, students in the cooperative condition were off-task academically (such as walking around the room) less frequently, initiated fewer interactions with the instructor, perceived the instructor to be more supportive, perceived the grading system to be fairer, and perceived the feedback received as being more helpful.

Adult↗
PubMed1993

Triad formation: organization and function of the sarcoplasmic reticulum calcium release channel and triadin in normal and dysgenic muscle in vitro.

Excitation-contraction (E-C) coupling is thought to involve close interactions between the calcium release channel (ryanodine receptor; RyR) of the sarcoplasmic reticulum (SR) and the dihydropyridine receptor (DHPR) alpha 1 subunit in the T-tubule membrane. Triadin, a 95-kD protein isolated from heavy SR, binds both the RyR and DHPR and may thus participate in E-C coupling or in interactions responsible for the formation of SR/T-tubule junctions. Immunofluorescence labeling of normal mouse myotubes shows that the RyR and triadin co-aggregate with the DHPR in punctate clusters upon formation of functional junctions. Dysgenic myotubes with a deficiency in the alpha 1 subunit of the DHPR show reduced expression and clustering of RyR and triadin; however, both proteins are still capable of forming clusters and attaining mature cross-striated distributions. Thus, the molecular organization of the RyR and triadin in the terminal cisternae of SR as well as its association with the T-tubules are independent of interactions with the DHPR alpha 1 subunit. Analysis of calcium transients in dysgenic myotubes with fluorescent calcium indicators reveals spontaneous and caffeine-induced calcium release from intracellular stores similar to those of normal muscle; however, depolarization-induced calcium release is absent. Thus, characteristic calcium release properties of the RyR do not require interactions with the DHPR; neither do they require the normal organization of the RyR in the terminal SR cisternae. In hybrids of dysgenic myotubes fused with normal cells, both action potential-induced calcium transients and the normal clustered organization of the RyR are restored in regions expressing the DHPR alpha 1 subunit.

Amino Acid Sequence↗
PubMed1992

News in diabetes.

Explore the source record for details and available documents.

Diabetes Complications↗
PubMed1992

HIV and AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Letters to the editor 1991. An audit of the MJA's correspondence columns.

OBJECTIVE: To evaluate correspondence published in The Medical Journal of Australia, with particular emphasis on the level of post-publication peer review which it represented. METHOD: An audit of all letters submitted to the Journal for publication in 1991. RESULTS: Six hundred and forty-eight letters were received; 506 (78%) were published and 142 (22%) were not. Three hundred and twenty-nine of the published letters were written in response to material published in the Journal: 96 of these were related to other letters, 71 were replies to other letters by authors, 43 related to original articles, 42 to leading articles and 77 to other articles. Approximately 20% of all original articles published in the Journal attracted correspondence which was published. The commonest reasons for writing were concern about possible flaws in the design of a study, to add information of interest to the subject or to criticise the conclusions reached in the study. CONCLUSIONS: Readers are perhaps not taking full advantage of the opportunity for post-publication peer review provided by correspondence columns in the MJA.

Australia↗
PubMed1992

News in dentistry.

Explore the source record for details and available documents.

Composite Resins↗
PubMed1992

Bon appétit.

Explore the source record for details and available documents.

Attitude to Health↗
PubMed1992

Cardiology.

Explore the source record for details and available documents.

Angioplasty, Balloon↗
PubMed1982

Extracapsular cataract extraction - some problems.

Comments are made on the method of removing the anterior capsule during the performance of extracapsular cataract operations. The difficulty of performing this manoeuvre adequately is emphasised. Observations carried out during the postoperative period by means of the slit-lamp revealed some hitherto undescribed changes in the capsule. The edge of the anterior capsule can be clearly seen and looks like broken glass. Fine fibrils have been observed attached to the fractured capsular edge. In the early postoperative period the anterior capsule tends to be separated from the posterior by quite a deep space, but at an early stage, usually about the fourth day, the edge of the anterior capsule becomes adherent to the posterior capsule, and rather rapidly a dense fibrous line forms along the joint.

Cataract Extraction↗