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Biomedical subjects

G Feldman

Publications and source records attributed to G Feldman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Azimuth errors in pointing to remembered targets under extreme head rotations.

Errors in pointing to remembered target locations in 3-D space were studied when subjects were free to move their heads, and when they rotated their heads to the extreme right or left. Relative to pointing when the head was free to move, head rotations to the right shifted the final position of the responding arm to the left, whereas head rotations to the left shifted the final position of arm to the right. Horizontal rotation of the head had no systematic influence on elevation and radial distance errors. The influence of head rotations on pointing errors may be mediated by small shifts in the internal representation of external space, shifting the presentation of space in the opposite direction of the head rotation.

Adult↗
PubMed1994

Regulation of amelogenin gene expression during tooth development.

The amelogenins are the predominant matrix proteins in developing enamel and are crucial for proper enamel mineralization. Transgenic mice were constructed in order to identify the segment of the amelogenin gene required for specific expression in enamel organ cells. A 3.5 kb fragment of the bovine X-chromosomal amelogenin gene that includes a TATA box, the transcription initiation site, and 32 bp of exon 1 was linked to the beta galactosidase gene and injected into fertilized mouse eggs. Newborn transgene positive mice expressed beta galactosidase activity in developing teeth treated with the chromogenic substrate Xgal. Foci of ameloblasts were positive in newborn mice; stain intensity and number of positive ameloblasts increased in 1-day and 2-day postnatal mice. Some of the adjacent stratum intermedium cells also were positive in the later stages. Targeting of the transgene to the enamel organ was specific; the only other cells observed to be positive were macrophages, which have endogenous beta galactosidase activity.

Ameloblasts↗
PubMed1993

Stimulation of HTLV-I expression by subtoxic dose of 3-methylcholanthrene.

In vivo infection by HTLV-I is characterized by the lack of virus expression in the host's infected cells and in most cases it is clinically inapparent. The present study shows that exposure of HTLV-I-infected human T-cells to a maximal non-toxic dose of 3-MC remarkably enhances virus expression. This stimulatory effect was demonstrated by showing elevated levels of viral RNA and proteins within the cells and increased virus release to the culture medium. The enhanced virus expression was found to increase the ability of the treated cells to infect normal human peripheral lymphocytes in co-culture. Such data point to the possibility that initiation of a pathogenic process in HTLV-I-infected individuals might result from activating the expression of the latent provirus by environmental carcinogens.

Cell Line, Transformed↗
PubMed1992

Endodontic stabilizers.

With the recent influx of osseointegrated endosseous implants in dentistry, attention has been drawn away from using endodontic stabilizers as a means of stabilizing and retaining teeth. It is our opinion that endodontic stabilizers should be considered in the treatment planning of seemingly nonretainable teeth. They are biocompatible and have the additional advantage of maintaining the periodontal membrane attachment of the remaining tooth. Extraction and subsequent replacement with osseointegrated implants should only be considered after all other means of retaining the natural tooth have been fully explored. Selective case studies from various areas of the dentition demonstrate the broad applicability of stabilizers. A technique is presented for the use of endodontic stabilizers.

Dental Abutments↗