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Biomedical subjects

M Hill

Publications and source records attributed to M Hill.

At least 343 records · Page 19Linked to original sources
PubMed1986

Interferon alpha/beta selectively antagonises down-regulation of mannosyl-fucosyl receptors on activated macrophages by interferon gamma.

Previous reports have described synergism of various interferon preparations in anticellular and antiviral activity. We report that recombinant interferon (rIFN gamma) and IFN alpha/beta mediate distinct, antagonistic effects on expression of a lectin-like receptor for mannose and fucose (MFR) on mouse peritoneal macrophages (M phi). IFN gamma down-regulates MFR activity, a highly reproducible change in mouse M phi activated to secrete enhanced levels of o-2/H2o2. IFN alpha/beta enhances MFR activity and prevents the action of IFN gamma when added in combination. Antagonism is selective for this M phi activation marker and requires a minimum 4 h exposure period to rIFN gamma, during which IFN alpha/beta can prevent its action.

Animals↗
PubMed1986

Symptoms of schizophrenia in Hispanic and Anglo veterans.

This study explores cultural influences on symptoms and course of schizophrenic disorder. Hispanic veterans with schizophrenia are compared to a similar group of White non-Hispanic (Anglo) veterans. Symptoms were elicited with a structured diagnostic interview and a battery of rating instruments. Primary symptoms of schizophrenia (e.g., hallucinations, delusions, functional deterioration) were very similar for both groups. However, Hispanic patients reported a later age of onset, exhibited more somatization, and spent less time in the hospital than Anglo patients.

Adult↗
PubMed1986

Dinoflagellate luminescence: purification of a NAD(P)H-dependent reductase and of its substrate.

The soluble enzymatic luminescent system of the dinoflagellate Pyrocystis lunula (luciferase-luciferin) is coupled with an enzymatic NAD(P)H-dependent reaction. The enzyme is a soluble reductase (Mr 47,000) which catalyzes, in the presence of NAD(P)H, the reduction of a molecule called P630. Reduced P630 has the same spectral characteristics as the purified luciferin. The luciferase can oxidize this reduced molecule with a light emission at 480 nm. These observations suggest that reduced P630 is a luciferin molecule. The oxidized form seems, in these conditions, to be the precursor of luciferin.

Animals↗
PubMed1986

Does a proton-pumping ATPase exist in the tonoplast?

In order to account for the accumulation of metabolites in plant vacuoles, the existence of a proton-pumping ATPase has been widely suggested in the literature. The demonstration of such a tonoplast-bound ATPase was merely based on the characterization of a nitrate-sensitive microsomal fraction. In some examples, this ATPase activity has been evidenced on vacuole preparations obtained under conditions which were criticized by Boller. The application of the reverse phase high-performance liquid chromatography method (RP-HPLC) to the simultaneous separation of adenine nucleotides, in the presence of tonoplast vesicles isolated from Catharanthus roseus, showed results not necessarily correlated with the ATPase hypothesis. Moreover, in light of the H+-quenching of quinacrine fluorescence observed during ATP hydrolysis by vacuoles or tonoplast vesicles, the existence of a proton-pumping ATPase may be questioned.

5'-Nucleotidase↗
PubMed1986

Loss of the oncogene from human H-ras-1-transfected NIH/3T3 cells grown in the presence of excess methionine.

Mouse NIH/3T3 cells, transfected with T24 genomic DNA (J10 cells), carry the human H-ras-1 (hu-H-ras-1) oncogene stably integrated in the chromosomal DNA and display the transformed phenotype with a "criss-cross" morphology and capacity for anchorage-independent growth. When these cells were cultured in the presence of 25 mM DL-methionine, they lost their transformed phenotype; the characters of the normal phenotype (before transfection) reappeared, even though cell viability, as measured by the cloning potential on a solid support, was fully conserved. Southern blot analysis showed that cells continuously propagated in methionine-supplemented medium (J10met), unlike cells grown in normal medium, progressively segregated the hu-H-ras-1 gene. The progressively fewer cells still retaining the oncogene could be selected by inoculation of J10met cells into nude (nu/nu) mice of Swiss background. After prolonged methionine treatment, however, no such oncogene-positive cells could be detected, even when the excess methionine was withdrawn from the culture medium after 105 days. Conclusive evidence for the loss of the hu-H-ras-1 oncogene sequence was provided by subcloning the J10met cells. The oncogene sequence could no longer be found, and a fraction of subclones was no longer tumorigenic when assayed in nude mice. Other subclones generated late tumors negative for the hu-H-ras-1 transforming sequence, and a small fraction of subclones gave rise to rapidly growing early tumors that were also negative for the transforming sequence. The question of how methionine can induce the phenotypic and genetic change from malignancy to normality is discussed.

Animals↗
PubMed1986

Non-random acquisition of ethionine resistance by Chinese hamster fibroblasts. Appendix: acquisition of thermoresistance.

When cells from a single culture are physically separated into cultures exposed and unexposed to the drug, respectively, the cells in the unexposed culture acquire drug resistance at a rate that is much higher than that predicted by Poisson's law. The results are in conflict with the spontaneous mutation hypothesis of Luria and Delbrück. Appendix: cells grown at 37 degrees C acquire temperature resistance when their close relatives are exposed to a high temperature in separate cultures.

Animals↗
PubMed1985

Impact of whooping cough on patients and their families.

The effects of whooping cough were studied in 21 children admitted to hospital with the disease and in their families. The illness caused considerable distress to both child and family. Parents suffered especially from fears for the life and health of their child and from serious loss of sleep. Two months after admission the child's behaviour was still disturbed, but in most cases the rest of the family had returned to normal. There was much misunderstanding and misinformation about whooping cough among both parents and doctors.

Acute Disease↗
PubMed1985

Isolation of a line of immortal chicken embryo fibroblasts after transfection with the nuclei of Rous sarcoma virus-transformed Chinese hamster cells.

Secondary cultures of chicken embryo fibroblasts were transfected with purified nuclei from lysed cells of a clonal line of temperature-sensitive Rous sarcoma virus (tsRSV)-transformed Chinese hamster fibroblasts. After propagation for 3 months an established cell line designated ChR32 was obtained in one chicken cell culture. The cells of this line have been propagated so far for 18 months, whereas normal chicken embryo fibroblasts died after 2 months. The established cells were heteroploid with a diploid modal number of macrochromosomes and two Z chromosomes. No Chinese hamster chromosomes could be identified. Southern blot analysis of DNA from the uncloned ChR32 cells and the clones provided evidence that these established cells were, in fact, clonal in origin and contained full-length RSV proviruses and no defective proviruses. Furthermore, they contained, at the 3' end proviral-cellular junction, Bg/II, HpaI, KpnI, SacI, and XbaI fragments of the same size as the Chinese hamster donor cells, suggesting that the cellular sequence adjacent to the provirus is of Chinese hamster origin. The cells after establishment were able to grow continuously at 37 degrees or 41 degrees C and produce a large amount of ts sarcoma virus particles. A corollary finding was that these virus particles were non-leaky for the transforming function at the non-permissive temperature.

Animals↗