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Biomedical subjects

S R Bauer

Publications and source records attributed to S R Bauer.

7 recordsLinked to original sources
PubMed1992

Pre-B lymphocyte-specific transcriptional control of the mouse VpreB gene.

The VpreB genes, which encode surrogate immunoglobulin light chain molecules, are expressed as RNA almost exclusively in pre-B cells. We have investigated the transcriptional control mechanisms which are responsible for the pre-B cell-specific RNA expression of the mouse VpreB1 and VpreB2 genes. Nuclear run-on analyses demonstrate that the pre-B cell-specific expression of both VpreB genes is controlled primarily at the level of initiation of transcription. S1 nuclease protection-mapping defined two or three major start sites of transcription for the VpreB genes. To find a promoter and other potential cis-acting regulatory elements, a 700-bp fragment 5' of the transcription start sites of the VpreB1 gene was used in gene transfer experiments and found to act as a promoter in pre-B lymphocytes. Deletion experiments showed that 191 bp upstream of the most 5' transcription start site is required for the pre-B cell promoter activity. DNA sequence analysis of the 5' region of the mouse VpreB1, VpreB2 and human VpreB genes reveal that this region of approximately 200 bp is strongly conserved. This 200-bp promoter region contains several conserved nucleotide sequence motifs which may act to mediate the pre-B cell-specific transcription of the VpreB genes.

Animals↗
PubMed1992

Loss of p53 expression in Myc-induced B lineage tumors.

Tumors are formed following the accumulation of several genetic changes in genes which normally function to regulate cell growth. As yet it is unclear why multiple mutations are required, which type of alterations can collaborate with each other, and if collaboration is cell-type specific. In our myc transgenic mouse model system both point mutations and loss of mRNA expression for the p53 tumor suppressor gene have been found in the myc-induced B-lineage tumors arising spontaneously in these mice. This demonstrates the collaboration between these two growth control genes in cellular transformation. The observation that alterations in the expression of p53 is a common phenomenon in tumors formed in myc transgenic mice as well as a variety of different types of human tumors suggests that inactivation of the p53 growth control pathway may be required for transformation, and that alterations in p53 itself might be the most efficient way to achieve this inactivation. An analysis of the molecular mechanism for p53 alterations has implications for what kind of factors, both environmental and physiological, can influence tumor formation. The identification of collaboration groups has implications for the process of tumor formation, growth regulation, and will some day be important for the diagnosis of cancer, the prognosis of the individual and the design of specific therapeutic agents for treatment.

Animals↗
PubMed1991

VpreB gene expression in hematopoietic malignancies: a lineage- and stage-restricted marker for B-cell precursor leukemias.

We show here that analysis of VpreB gene transcription can be a specific way to identify acute leukemias of cells at very early stages of B-cell development. Northern blot analysis of RNAs from 63 leukemia samples showed that VpreB RNA was present in malignancies of precursor B cells, the expression being a feature of both common acute lymphoblastic leukemia (ALL) (CD10+) and null ALL (CD10-). It was absent from malignancies of mature B cells (surface Ig positive), from acute leukemias of the T-cell lineage and granulocyte-macrophage lineages, and from normal tonsil B and T lymphocytes. Chronic myeloid leukemia blast crises of the B-precursor-cell type expressed the VpreB gene while myeloid blast crises did not. VpreB RNA was also expressed in the neoplastic cells of one of three patients with acute undifferentiated leukemias. These data show that VpreB RNA expression is a marker of the malignant forms of precursor B cells, and that it appears at least as early as cytoplasmic CD22 and CD19 in tumors of the B-cell lineage.

Blotting, Northern↗
PubMed1977

A comparative study of iodine uptake by thyroid and thymus glands of male and female Sprague-Dawley rats of different ages.

The iodine concentrating ability of thyroid glands, thymus gland and skin in Sprague-Dawley rats was assessed by determining the tissue/blood radioiodide concentration ratios. Tissue/blood ratios are significantly affected by the age of the rats, however, thymus/blood radioiodide ratios never exceeded unity. The comparative uptake of 131I by thymus and thyroid tissue expressed as thymus/thyroid (%) for neonate animals was 10-16 times greater than those obtained for older rats. Moreover, the fraction of injected dose of radioiodide in thymus tissue never exceeded that of the thyroid or skin and paralleled the concentration of radio-activity in the blood. These results indicate that although neonate thymus tissue contains a significantly greater amount of radioactivity than the thymus of older rats, an active iodide concentration mechanism is not involved.

Age Factors↗
PubMed1976

Self-image disparity, repression-sensitization, and extraversion-introversion: a unitary dimension?

To determination (1) whether self-image disparity, repression-sensitization, and extraversion-introversion intercorrelated to a degree indicative of a unitary personality dimension and, (2) whether the interrelationships among these variables was accounted for by cognitive developmental variance, Byrne's Revised Repression-Sensitization Scale, Giedt and Downing's Extraversion-Introversion Scale, and two measures of self-image disparity were administered to 20 male college freshmen and 20 male seniors. All the correlations among the four measures were significant, but none correlated significantly with cognitive development, as measured by SATs. Factor analysis yielded a clearcut personality factor and a clearcut cognitive factor, indicating that the personality measures reflect a unitary dimension, even after cognitive developmental variance is extracted.

Adolescent↗