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B Steinberg

Publications and source records attributed to B Steinberg.

7 recordsLinked to original sources
PubMed1992

Potential language and attentional networks revealed through factor analysis of rCBF data measured with SPECT.

We used changes in regional cerebral blood flow (rCBF) to disclose regions involved in central auditory and language processing in the normal brain. rCBF was quantified with a fast-rotating, single-photon emission computerized tomograph (SPECT) and inhalation of 133Xe. rCBF data were obtained simultaneously from parallel, transverse slices of the brain. The lower slice was positioned to include both Broca's and Wernicke's areas. The upper slice included regions generally regarded by neurobehaviorists as less related to primary auditory or linguistic functions. We presented three types of auditory stimuli to ten healthy, young volunteers: (a) diotically presented Danish speech, (b) dichotic word stimulation, and (c) white noise. Wilcoxon's signed ranks sum test revealed increased rCBF in language-related areas of cortex, viz., Wernicke's area and its right-sided homologous area as well as in Broca's area (left hemisphere), when subjects listened to narrative speech, compared to white noise (baseline). No significant rCBF differences were detected with this test during dichotic stimulation vs. white noise. A more sophisticated statistical method (factor analysis) disclosed patterns of functionally intercorrelated regions. The factor analysis reduced the highly intercorrelated rCBF measures from 28 regions of interest to a set of three independent factors. These factors accounted for 77% of the total variation in rCBF values. These three factors appeared to represent statistical analogues of independent brain networks involved in (I) auditory/linguistic, (II) attentional, and (III) visual imaging activity.

Acoustic Stimulation↗
PubMed1991

Ultrastructural characteristics of a cell line derived from a melanotic neuroectodermal tumor of infancy.

Thin section and freeze-fracture transmission electron microscopy were used to examine and identify the cytoplasmic and membrane structures in a cell line derived from a melanotic neuroectodermal tumor of infancy (MNTI). The cultured cells had a uniform appearance after 70 population doublings characterized by long dendritic processes and evidence of melanin production. The cytoplasm contained numerous melanosomes in various stages of development, vesiculated rough endoplasmic reticulum, microfilaments and uncoated as well as coated vesicles. The membrane specializations included caveoli, coated pits, gap junctions, microfilaments, desmosome-like structures and lamellipodia. The ultrastructural appearance of the cultured MNTI cells was similar to features previously seen in electron micrographs of MNTI tumor specimens. However, correlated freeze-fracture and thin section micrographs permitted further identification of structures previously described. The MNTI cell line represents one of the cell types of the tumor and provides an opportunity for further study of the pathogenesis of this rare tumor.

Cell Line↗
PubMed1978

Isolation and characterization of T antigen-negative revertants from a line of transformed rat cells containing one copy of the SV40 genome.

Negative selection with FUdR produced revertants from the transformed rat line 14B, which contains one insertion of the SV40 viral genome (Botchan, Topp and Sambrook, 1976). 14B contains nuclear T antigen, grows to a high density, grows in low serum and is anchorage-independent. The revertants fall into three classes with regard to viral DNA sequences: the SV40 DNA is retained; the SV40 DNA is retained but has undergone a deletion; and the SV40 DNA is lost, generating a cured cell. This heterogeneity is not a result of long-term passage. The revertants arise with a frequency of one in 8.4 X 10(5) cells after as few as 12 passages. All three classes of revertants are T antigen-negative, density-sensitive, more serum sensitive than 14B and anchorage-dependent. These data argue for a direct role of the functioning viral genome in the maintenance of the transformed state, and that with 14B, the phenotypes of transformation are not virus gene dosage-dependent.

Antigens, Viral↗
PubMed1975

Altered DNA synthesis in a mutant of Salmonella typhimurium that channels bacteriophage P22 toward lysogeny.

Pox-1, a mutant of Salmonella typhimurium, strongly channels P22 toward lysogeny. Viral DNA synthesis in this slow-growing mutant is delayed to a greater extent than viral protein synthesis. The relative enhancement of c2 repressor synthesis results in much higher repressor/DNA synthesis ratios in Pox-1 than in wild-type cells. This probably accounts for the high frequency of lysogenization.

DNA Replication↗