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Biomedical subjects

K Izutsu

Publications and source records attributed to K Izutsu.

90 records · Page 5Linked to original sources
PubMed1985

Association of anti-dynein-1 cross-reactive antigen with the mitotic spindle of mammalian cells.

Two anti-dynein-1 antibodies were affinity-purified from rabbit antiserum produced by immunization with dynein-1 from sea urchin sperms. One was prepared with dynein-1 as the ligand and the other with the A heavy chains of dynein-1 as the ligand. In Western blots of axonemal proteins, the former antibody reacted with the A heavy chains of dynein-1 as well as with several other smaller polypeptides, whereas the latter bound almost exclusively to the A heavy chains. PtK2 cells stained by indirect immunofluorescence with either of these antidyneins had identical fluorescence patterns. The interphase cell showed rather diffuse and weak fluorescence in its nucleus and perinuclear cytoplasm. Its primary cilium and its centrioles also fluoresced. During prophase and prometaphase, a more intense fluorescence was present in the asters and developing spindle. During metaphase and anaphase the half-spindles fluoresced intensely in a fibrous pattern that corresponded to that of the spindle fibers, showing less intense fluorescence in the anaphase interzone. In telophase and early interphase, the intercellular bridge on each side of the midbody also was stained. These results are evidence that dynein-1, specifically the A heavy chains and/or a related antigen, is densely packed in the mitotic spindle of PtK2 cells.

Adenosine Triphosphatases↗
PubMed1985

Mechanisms of interleukin-2-mediated signaling and role of calcium in T cell mitogenesis.

In T lymphocytes stimulated by concanavalin A (Con A), interleukin 2 (IL-2) acts on the late G1 stage of the cell cycle. Ca2+ uptake by T cells was not enhanced with the stimulation of Con A (initiation) or IL-2 (late G1 stage), but Ca2+ requirement was observed at the two stages. These results indicate that the enhancement of Ca2+ uptake is not necessary, but intracellular Ca2+ may act as an important messenger in T cell mitogenesis.

Biological Transport, Active↗
PubMed1983

Studies on endoreduplication. III. Endoreduplication induced by mitomycin C in PHA-stimulated tonsillar lymphocyte cultures.

The activity of mitomycin C (MMC) to induce endoreduplication was examined in PHA-stimulated tonsillar lymphocyte cultures. Cellular kinetics of both diploid and endoreduplicated cells was studied by the combined techniques of thymidine and BrdU incorporation. The kinetic data showed that the increase of endoreduplicated cells induced by MMC correlated with the increase of the second-generation diploid cells. Also, it showed that the majority of endoreduplicated cells found at the time when the maximal number of endoreduplicated cells was obtained had incorporated BrdU only once into their diplochromosomes. This suggests that MMC-induced endoreduplicated cells originate from MMC-induced G2-arrested cells.

Cells, Cultured↗
PubMed1981

Studies on endoreduplication. II. Spontaneous occurrence and cellular kinetics of endoreduplication in PHA-stimulated tonsillar lymphocytes.

Cells with spontaneously endoreduplicated chromosomes were observed in tonsillar lymphocyte cultures from the second to the seventh day of culture, although at a low frequency. Cell cycle kinetics leading to endoreduplication were examined by the 5-bromodeoxyuridine (BrdU)-acridine orange method. The diplochromosomes showed four fluorescent patterns depending on the period during which BrdU was incorporated into the DNA. The kinetic data also revealed two populations among the cells with endoreduplicated chromosomes: one with a shorter (36 or 48 h) and the other with a longer cell cycle time. The existance of the latter population was shown by the fact that cell without differentially stained chromatids were observed many hours after BrdU addition (up to 120 h). This suggests that some cells with endoreduplicated chromosomes originate from cells arrested in G2.

Aneuploidy↗
PubMed1980

A solid phase immunofluorescent assay for the measurement of salivary immunoglobulin and albumin levels.

A solid phase immunofluorescence assay which can be used to measure immunoglobulin and albumin levels in whole saliva, as well as in duct collected saliva samples, is described. This method is about an order of magnitude more sensitive than the conventional radial immunodiffusion method, allowing its use in situations involving large numbers of samples or restricted sample volumes. The relative precision and accuracy of this method are comparable to those of radial immunodiffusion.

Adolescent↗
PubMed1978

Malakoplakia of the stomach. Report of a case and review of the literature.

A case of malakoplakia of the stomach associated with well-differentiated adenocarcinoma of the transverse colon was studied by light and electron microscopy. The gross appearance consisted of a slightly elevated plaque with umbilication of the covering mucosa. Histologically, the lesion was composed of submucosal proliferation of histiocytes with the typical cytoplasmic inclusions known as Michaelis-Gutmann bodies. Ultrastructurally, these inclusions had a dense central calcified body and concentric alternating rings. Twenty-four cases of gastrointestinal malakoplakia from the literature, including two cases of gastric malakoplakia, were reviewed.

Adenocarcinoma↗
PubMedDate not supplied

Histopathology of nude mice induced by granulocyte-macrophage colony-stimulating factor.

Significant elevation in the peripheral granulocyte count (more than 20,000) and the absence of overt infection are commonly associated with a wide variety of human neoplasms. Robinson demonstrated a dose correlation between the amount of the serum and urine levels of granulocyte-macrophage colony stimulating factor (GM-CSF) and the peripheral neutrophil counts. In vivo assessment of hematopoietic activities induced by GM-CSF has not been explored owing to the complexity, time consuming, and ill-defined specific results. This experiment is designed to understand the pathophysiology of the hematopoiesis induced by GM-CSF released from tumor of Chinese Hamster Ovary (CHO) cell line in nude mice. To our knowledge, this experiment is the first one to describe detailed histopathological changes induced by GM-CSF. Three to five months old nude mice inoculated subcutaneously with the CHO cell line developed local tumor with or without metastasis and hepatosplenomegaly. Active granulopoiesis is demonstrated in bone marrow, spleen, liver, and some of the tumors. Lymph nodes show histiocytic proliferation, however, without active granulopoiesis. Peripheral granulocytosis seems to be not linearly but step-wisely coordinated with tumor growth.

Animals↗
PubMedDate not supplied

Deterministic chaos in the hemodynamics of an artificial heart.

To analyze the hemodynamic parameters during prosthetic circulation as an entity, non linear mathematical techniques were used. To compare natural and prosthetic circulation, two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses in chronic animal experiments using adult goats to consitute the biventricular bypass complete prosthetic circulation model with ventricular fibrillation. After implantation, these goats were placed in a cage and extubated after waking. All hemodynamic parameters with the natural circulation without biventricular bypass pumping, and the artificial circulation with biventricular bypass pumping under ventricular fibrillation were recorded under awake conditions. By the use of a non linear mathematical technique, the arterial blood pressure waveform was embedded into a four dimensional phase space and projected into three dimensional phase space. The Lyapunov numeric method is used as an adjunct to the graphic analysis of the state space. A phase portrait of the attractor showed a high dimension complex structure, with three dimensional solid torus suggesting deterministic chaos during natural circulation. However, a simple attractor, such as a limit cycle attractor, was observed during artificial circulation. Positive Lyapunov exponents during artificial circulation suggest the lower dimensional chaotic system. Thus, hemodynamic parameters during prosthetic circulation must be carefully controlled when unexpected stimuli are fed from outside.

Animals↗