Search PubMedSearch

Biomedical subjects

Y Yuasa

Publications and source records attributed to Y Yuasa.

At least 109 records · Page 6Linked to original sources

Autonomic nervous dysfunction in patients on long-term hemodialysis.

The level of plasma dopamine-beta-hydroxylase (DBH) activity in subjects at rest was found to be significantly lower in 12 patients on long-term hemodialysis than in a healthy 8-member control group: 28.3 +/- 7.2 and 13.6 +/- 7.6 IU/1, respectively (p less than 0.01). Following immersion of one hand of each subject into cold water (4 degrees C) for 1 min, a significant rise was observed in both groups, 6.1 +/- 4.8 IU/1 for the control and 1.6 +/- 1.4 IU/1 for the patient group (p less than 0.01). Upon tilting up the head of all subjects, activity in both groups increased significantly, but a markedly smaller rise was found in the patient group: 5.8 +/- 4.8 and 1.1 +/- 1.6 IU/1 for the two groups, respectively (p less than 0.01). The data suggest an autonomic nervous dysfunction in patients on long-term hemodialysis.

Adult

Phosphorylation of chromatin- and ribosome-associated proteins in cells transformed by adenovirus, murine sarcoma virus, and methylcholanthrene.

Endogenous protein phosphorylation in chromatin and ribosomes of monkey, mouse, and rat cells transformed by DNA, RNA tumor viruses, and a chemical carcinogen revealed the association of a protein of approximately 90,000 daltons (90K), which is highly phosphorylated in vitro. Peptide map analysis showed that the 90K proteins associated with these organelles of various transformed cells are similar irrespective of the species of cells and transforming agents. This species of protein could not be detected, or was scarcely detected, by phosphorylation in chromatin and ribosomes of untransformed cells and in revertants of transformed cells. These results suggest that the alteration in the pattern of endogenous protein phosphorylation in these organelles is closely related to the transformed state of cells.

Adenoviruses, Human

Transformation of Indian muntjac cells by murine and avian sarcoma viruses.

Indian muntjac cells were efficiently transformed by murine sarcoma virus (MSV) and avian sarcoma viruses (ASV). When colony formation of the infected cells was examined in soft agar, many colonies were formed by the ASV-injected cells but no colony was seen in the MSV-infected cells. The ASV-transformed cell clones differed among the clones in morphology, presence of inducible ASV genome, and karyotypes.

Alpharetrovirus

Isolation and preliminary characterization of temperature-sensitive mutants of the murine sarcoma leukaemia virus complex.

Five temperature-sensitive mutants (ts I to 5) were isolated from a stock of the Moloney strain of murine sarcoma leukaemia virus complex which had been mutagenized by ultraviolet irradiation or N-methyl-N'-nitro-N-nitrosoguanidine. In mouse cells at the non-permissive temperature the mutants formed fewer foci of transformed cells than at the permissive temperature. The ts mutants were characterized by testing: (I) murine leukaemia virus (MuLV) clones from the ts complex, (2) the effect of additional wild type MuLV on focus formation, (3) focus formation in rat cells and (4) focus formation with pseudotypes rescued from non-producer cells. Two mutants (ts 1 and ts 3) were found to be ts MuLVs which did not possess heat labile virion proteins and were not ts in post-penetration helper functions necessary for the fixation of sarcoma virus transformation. The remaining three mutants (ts 2, ts 4 and ts 5) were ts murine sarcoma viruses which, however, showed no temperature-sensitive effect on the maintenance of transformed cell morphology nor on colony forming efficiency in soft agar.

Animals

Diminished vascular reactivity to a cold stress in azotemic patients.

The integrity of the neurovascular reflex arc to a cold stimulus was evaluated by the determination of the response of the limb blood flow in fifteen azotemic patients. Seven of these patients became hypotensive during the course of renal failure despite comparable hemodialysis therapy. They showed a constant low blood pressure (mean blood pressure below 90 mmHg). The reactivity index (defined as the relative change at the 15th second of stimulus) was 15.9 +/- 14.4% for these hypotensive patients, and 35.7 +/- 12.0% for the remaining eight normotensive ones, while that of healthy subjects was 48.7 +/- 8.7%. The greatly diminished reactivity of the hypotensive patients could not be explained by humoral or hormonal factors. The dysfunction of somatic nerves of the vascular geometry could not be responsible for the difference. A dysfunction of adrenergic control of blood pressure was, therefore, strongly suggested.

Adult

Mouse strain resistant to N-, B-, and NB-tropic murine leukemia viruses.

Mouse strain G was studied for its susceptibility to various strains of murine leukemia and sarcoma viruses. Both N- and NB-tropic Friend leukemia viruses neither induced splenomegaly nor grew efficiently in strain G mice. Using the XC test, cultured embryo cells were found to be resistant, but not absolutely, to all the tested viruses, N-tropic AKR virus, N- and NB-tropic Friend leukemia viruses, NB-tropic Rauscher leukemia virus, B-tropic WN1802B virus, NB-tropic Moloney leukemia and sarcoma viruses, and N-tropic Kirsten sarcoma virus, although the resistance to Moloney leukemia and sarcoma viruses is sometimes not as strong as that for other viruses. Thus, the strain G mice are unique among mouse strains because they show resistance that is not related to the N-B tropism of murine leukemia viruses.

AKR murine leukemia virus

Effect of protease inhibitors on focus formation by murine sarcoma virus.

The effect of six protease inhibitors, isolated from various species of actinomycetes, on focus formation by murine sarcoma virus was examined. Pepstatin was the only inhibitor. The treatment of cells with pepstatin at various times possibly retards the early stage of infection with murine sarcoma virus.

Animals

Development of a 3T3-like line from an embryo culture of an inbred strain of Syrian golden hamster.

An embryo culture of an inbred strain of Syrian hamster developed into a permanent cell line under the "3T3" 3 X 10-5 cells/60-mm dish. The resulting cell line had properties very similar to those of the mouse 3T3 series and was named HAMS 3T3. The cell showed density-dependent inhibition of division with a saturation density of 1.0 to 1.2 x 10-6 cells/60-mm dish or 4.5 to 5.5 x 10-4 cells/sq cm. Addition of fresh medium containing 5 or 10% fetal calf serum to a confluent culture induced DNA synthesis in 18 hr with subsequent cell division. Cells were hyperdiploid with a mode of 45 chromosomes (80% of the cells). When cells at the 60th passage were injected into the skin or cheek pouch of an inbred hamster of the same strain as that from which they were derived, they produced a benign tumor that regressed after 3 weeks. Morphological transformation was obtained by infection with the Moloney strain of murine sarcoma virus.

Animals