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Biomedical subjects

J Stein

Publications and source records attributed to J Stein.

At least 343 records · Page 19Linked to original sources
PubMed1988

Patient anesthesia and monitoring at a 1.5-T MRI installation.

This paper describes the facilities successfully used to provide patient monitoring and anesthesia support in a 1.5-T imaging installation. The requirements for the MRI site for anesthetic gases, shielded power, and radiofrequency ports are outlined. Specific modifications in anesthesia machines, anesthesia cart, laryngoscope, mercury sphygmomanometer, oximeter, and remote blood pressure devices are described. Additional aspects of patient monitoring and support, e.g., electrocardiogram and pressure infusion, are also discussed.

Anesthesiology↗
PubMed1988

Autologous antibodies to human bladder cancer.

The autologous serologic reactivity of 13 patients with bladder cancer was evaluated using cell lines derived from each individual's own tumor as targets. Protein A and immune adherence assays were employed to determine antibody binding to the tumor targets at varying passage numbers. Autologous reactivity was found in 6 of the 13 cell lines tested. However, the titer was usually low regardless of the passage number. Seven autologous serum/cell line combinations were tested using both low and high passage cells as targets. In six of these combinations, the degree of antibody binding was similar with both low and high passage target cells. The incidence of autologous reactivity in the 12 patients with urothelial tumors was 50%.

Animals↗
PubMed1988

Isolated ventral pancreatitis in an alcoholic with pancreas divisum.

An alcoholic with no history of clinical pancreatitis was found to have pancreas divisum and marked changes of chronic pancreatitis isolated to the ventral pancreas. Pancreas divisum has been suggested to cause recurrent pancreatitis in some patients. Gross and histologic changes of pancreatitis in only the dorsal pancreas of surgically resected specimens from patients with pancreas divisum is thought to support the concept that obstruction at the minor papilla produces dorsal pancreatitis. Alternative explanations for the occurrence of segmental pancreatitis and the possible synergistic role of ethanol and bile are reviewed.

Adult↗
PubMed1988

Native genomic blotting: high-resolution mapping of DNase I-hypersensitive sites and protein-DNA interactions.

DNase I-hypersensitive sites are observed in the promoter regions of actively expressed genes, potentially active genes, and genes that were once active. We have developed an approach that greatly increases the resolution for mapping these sites by electrophoresing genomic DNA on native polyacrylamide gels prior to electroblotting and hybridization. This improved method has been used to scan the promoter and coding region of a cell-cycle-dependent human histone H4 gene with an accuracy of +/-5-10 base pairs. Protein-DNA interactions can be seen in the autoradiograph as light areas and DNase I-hypersensitive sites as dark bands. Therefore, this method provides a rapid and relatively simple means to accurately localize protein-DNA interactions as well as DNase I-hypersensitive sites, thus directly displaying DNase I hypersensitivity and protein-DNA complexes on one autoradiograph. It also potentially allows the analysis of small changes in DNase I-hypersensitive sites under various biological conditions. With this technique rather large regions of DNA can be screened to determine areas that should be analyzed by more sophisticated methods, such as genomic sequencing or gel retardation assays.

DNA, Neoplasm↗
PubMed1988

Changes in DNA base sequence induced by gamma-ray mutagenesis of lambda phage and prophage.

Mutations in the cI (repressor) gene were induced by gamma-ray irradiation of lambda phage and of prophage, and 121 mutations were sequenced. Two-thirds of the mutations in irradiated phage assayed in recA host cells (no induction of the SOS response) were G:C to A:T transitions; it is hypothesized that these may arise during DNA replication from adenine mispairing with a cytosine product deaminated by irradiation. For irradiated phage assayed in host cells in which the SOS response had been induced, 85% of the mutations were base substitutions, and in 40 of the 41 base changes, a preexisting base pair had been replaced by an A:T pair; these might come from damaged bases acting as AP (apurinic or apyrimidinic) sites. The remaining mutations were 1 and 2 base deletions. In irradiated prophage, base change mutations involved the substitution of both A:T and of G:C pairs for the preexisting pairs; the substitution of G:C pairs shows that some base substitution mechanism acts on the cell genome but not on the phage. In the irradiated prophage, frameshifts and a significant number of gross rearrangements were also found.

Bacteriophage lambda↗
PubMed1988

Poverty, health services, and health status in rural America.

Access to health services for everyone has been a major policy goal in the United States: inequitable access is assumed to lead to inequitable health status, particularly for low-income groups. A sophisticated model of the relation between poverty, health care needs, service use, and health outcomes is used to analyze cross-sectional data on 7,823 adults from 36 rural communities. Improved access and use are helpful, but evidence clearly indicates that combined health and social initiatives will be necessary to reduce inequalities in health status.

Cross-Sectional Studies↗
PubMed1988

Native genomic blotting: a novel approach to mapping DNase I hypersensitive sites and protein-DNA interactions at high resolution.

We have developed a new high resolution method for screening 400-600 base pairs of DNA in chromatin for DNase I hypersensitive sites and protein-DNA interactions. By separating the DNA isolated from nuclease-digested nuclei in small, native polyacrylamide gels prior to electroblotting onto nylon membranes, we increased the resolution by greater than 3-fold as compared with the traditional approach whereby the nuclease-digested DNA is fractionated electrophoretically in agarose gels (11). In addition, our native genomic blotting method has the advantage of combining the ability of the traditional agarose approach to detect DNase I hypersensitive sites, with the genomic sequencing method (2), where individual protein-DNA contacts can be observed. Native genomic blotting therefore permits for the first time the display of DNase I hypersensitive sites and protein-DNA interactions at high resolution on the same autoradiograph. This method allows us to investigate a new level of chromatin structure and to therefore obtain better insight into levels of gene structure, organization and gene regulation.

Autoradiography↗
PubMed1987

Differing patterns of human protooncogene expression in peripheral blood and bone marrow acute leukemia cells.

The levels of protooncogene RNA in matched bone marrow and peripheral blood cells obtained from patients with newly diagnosed acute myelogenous leukemia were compared. While the absolute amounts of c-myc RNA in the matched specimens are similar, the levels are not correlated. In contrast, while the levels of c-fos RNA in the matched bone marrow and peripheral blood cells are correlated, the absolute levels of c-fos RNA differ substantially. The level of histone H3 RNA is higher in bone marrow cells than in peripheral blood cells. These substantial differences in protooncogene RNA levels between leukemic cells found in the bone marrow and in the peripheral blood make it impossible to accurately "characterize" gene expression in leukemic cells if studies are restricted to the cells in either compartment. Additionally, there appears to be a significant relationship between the levels of c-fos RNA and triose phosphate isomerase RNA and the height of the white blood cell count and between the level of c-fos RNA in marrow cells and the proportion of monocytic cells present.

Bone Marrow Cells↗
PubMed1987

Protein-DNA interactions in vivo upstream of a cell cycle-regulated human H4 histone gene.

Cell cycle-dependent histone genes are transcribed at a basal level throughout the cell cycle, with a three- to fivefold increase during early S phase. Protein-DNA interactions in the 5' promoter region of a cell cycle-regulated human H4 histone gene have been analyzed at single-nucleotide resolution in vivo. This region contains two sites, with four potential protein-binding domains, at which the DNA is protected from reaction with dimethyl sulfate in cells and from digestion with deoxyribonuclease I in nuclei. These protein-DNA interactions persist during all phases of the cell cycle and dissociate with 0.16 to 0.2M sodium chloride.

Base Sequence↗
PubMed1987

Coordinate turnover of nuclear and cytoplasmic histone messenger RNA following inhibition of DNA replication in HeLa S3 cells.

We have examined the metabolism of human H4 histone mRNA in the nucleus and cytoplasm of HeLa S3 cells following inhibition of DNA synthesis to address the extent to which histone mRNA stability in these cellular compartments is coupled to DNA replication. The nuclear and cytoplasmic levels of histone mRNAs encoded by the pF0108A human H4 histone gene were determined by S1 nuclease analysis using a 32P-labeled probe that could distinguish pF0108A transcripts from those of other members of the H4 histone multigene family. Hydroxyurea treatment resulted within 15 min in a 75% reduction in the level of histone H4 mRNA in the nucleus, which corresponds to the 85% decrease observed for H4 histone mRNA in the cytoplasm. The kinetics of nuclear and cytoplasmic H4 mRNA turnover following hydroxyurea treatment were also similar. Northern blot analysis using a 32P-labeled mitochondrial cytochrome b probe indicated that the association of cytoplasmic RNA with the nuclear fraction was less than 0.5%. Treatment of cells with a protein synthesis inhibitor resulted in a 1.3-fold increase in nuclear H4 histone mRNA levels and a 1.5-fold increase of H4 mRNA in the cytoplasm after 45 min. Together, these results indicate that nuclear and cytoplasmic H4 histone mRNAs respond similarly to metabolic perturbations that influence message stability and that mechanisms operative in the turnover of histone mRNAs in the nucleus and cytoplasm may be similar.

Cell Cycle↗
PubMed1987

A rat histone H4 gene closely associated with the testis-specific H1t gene.

A rat histone H4 gene closely associated with the testis-specific H1t gene was isolated by screening the Sargent-Bonner rat genomic library using cloned human histone genes as probes. Both the H4 gene and the H1t gene are located on a 7-kb EcoRI genomic DNA fragment. Although the deduced amino acid sequence of the rat H4 histone is identical to that of the sequence of human histone H4, the nucleotide sequence of the coding region differs significantly from the coding region of the human H4 gene. Moreover, the relative spacing between the 5'-consensus sequence elements is unique for an H4 gene. S1-nuclease protection analyses reveal that both the H4 and H1t mRNA species are present in a fraction of rat testis cells highly enriched in pachytene spermatocytes, while only the H4 mRNA species is present in a rat myeloma cell line (Y3-Ag1.2.3). During a 1-h hydroxyurea treatment of the Y3 cells, which produces a 99% inhibition of DNA synthesis, the level of this H4 mRNA drops by only 50%, indicating that the stability of this mRNA is only partially coupled with DNA synthesis.

Amino Acid Sequence↗
PubMed1987

Histone gene expression remains coupled to DNA synthesis during in vitro cellular senescence.

Despite a decrease in the extent to which confluent monolayers of late compared to early passage CF3 human diploid fibroblasts can be stimulated to proliferate, the time course of DNA synthesis onset is similar regardless of the in vitro age of the cells. A parallel and stoichiometric relationship is maintained between the rate of DNA synthesis and the cellular levels of histone mRNA independent of the age of the cell cultures. Furthermore, DNA synthesis and cellular histone mRNA levels decline in a coordinate manner after inhibition of DNA replication by hydroxyurea treatment. These results indicate that while the proliferative activity of human diploid fibroblasts decreases with passage in culture, those cells that retain the ability to proliferate continue to exhibit a tight coupling of DNA replication and histone gene expression.

Cell Survival↗