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Biomedical subjects

J Stempak

Publications and source records attributed to J Stempak.

5 recordsLinked to original sources

Implementing and integrating computer-based activities into a problem-based gross anatomy curriculum.

A problem-based learning curriculum in gross anatomy was begun for a limited number of students to address unsuccessful methodology inherent in a traditional instructional approach. To eliminate some concerns associated with the laboratory component, computer-based instruction and other computer- related activities were actively integrated into the total instructional process. Prosections, directions, quizzes, images, and grades were provided in lab at table-side computer workstations, in the library, and on the web. Results were assessed through questionnaires in which students rated their learning experience according to a Likert-type scale. Success was measured by quantitative improvements in student perception. In this three-year study, observations and measurements have suggested increasingly positive student attitudes toward educational technology, for networks as a faster and more effective method of student/faculty communication, and in the utilization of computer-based instruction for greater flexibility and efficiency in learning. This allowed a rethinking of the structure and content of the curriculum by the faculty, which permitted reduced laboratory time, more small-group activity, and less reliance on staff.

Anatomy↗

The DM20 protein of myelin: intracellular and surface expression patterns in transfectants.

DM20 is an abundant CNS myelin-specific protein whose role in myelinogenesis is unknown. We have cloned the DM20 cDNA from adult mouse brain total RNA using the polymerase chain reaction and expressed it in HeLa cells. DM20, detected by immunofluorescence in stable transfectants, is present in some cells in large, intensely fluorescent intracellular clumps that probably represent elements of the rough endoplasmic reticulum and Golgi apparatus. Frequently, intense DM20 fluorescence could be detected at the plasma membrane. These findings are consistent with previous studies demonstrating that an intracellular "pool" of DM20 and its larger isoform, proteolipid protein, exists and that a substantial lag occurs between synthesis and insertion of these proteins into the expanding myelin membrane. Permanent DM20 expressors in contact with one another do not display any ultrastructural rearrangements at regions of cell-cell contact, in contrast to what we have previously reported for P0, a PNS-specific protein shown to mediate adhesion of the extracellular faces of the Schwann cell during PNS myelinogenesis. We believe that these results indicate that if DM20 is indeed an adhesion molecule, this property is likely to be significantly more subtle than P0-mediated adhesion.

Amino Acid Sequence↗

Mitochorial form in hepatic parenchymal cells in rats of several ages.

Slices of livers from neonatal, 7-day-old and adult rats were fixed in osmium tetroxide or a formaldehyde-osmium tetroxide sequence and processed for electron microscopy. Mitochondria from neonatal hepatic parenchymal cells are pleomorphic. Disc-shaped forms are common. In 7-day-old animals, cylinders are the most numerous single form, discs are present but smaller, and spherical forms increase in number. In the adult, mitochondria are predominantly cylindrical in form. The average volume of neonatal mitochondria is greater than that of 7-day-old or adult mitochondria.

Age Factors↗