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Biomedical subjects

Y Iwama

Publications and source records attributed to Y Iwama.

51 records · Page 3Linked to original sources
PubMed1989

The foci of the red bone marrow observed in the laryngeal cartilages of the Suncus murinus.

In the Suncus murinus, the thyroid, the cricoid and the arytenoid cartilages were in part ossified. The foci of the red bone marrow, termed as the "marrow foci", were observed in the ossified portion of the cartilages. The marrow foci were filled with mature and immature blood cells. It is suggested that the marrow foci take part in active hematopoiesis in the Suncus. Further, a canal which connected the marrow cavity and the outside of the cartilage was occasionally seen. It seems that the canal corresponds to the nutrient canal.

Animals↗
PubMed1988

Correlation of spatial differences in concentrations of prolactin and growth hormone cells with vascular pattern in the female mouse adenohypophysis.

Adult female mice of the DDY/S strain were used to study the distribution of PRL or GH cells and the vasculature of the anterior pituitary lobe. Electron microscopy was used to quantify PRL or GH cells in horizontal sections. Most parenchymal cells were either PRL or GH cells, and both types of cells were present in all regions. The densities of PRL cells in the rostral and caudal areas were significantly greater than that of GH cells. The density of GH cells was greater in the anterolateral wings. Thus, the spatial differences in concentrations of PRL and GH cells were reversed. The vasculature was studied with scanning electron microscopy of vascular casts and with stereoscopy of pituitary glands injected with India ink. The adenohypophysis was supplied by long and short portal vessels. The long portal vessels originated from the primary capillary plexus on the median eminence and the upper portion of the pituitary stalk, and they supplied rostral regions of the adenohypophysis. Most of the short portal vessels connected caudal areas of the anterior lobe with the posterior lobe, crossing the surface of the intermediate lobe. The blood in the short portal vessels may flow from the posterior lobe toward the anterior lobe. Thus, within the rostral and caudal areas, which are supplied by long and short portal vessels, respectively, PRL cells predominated; the anterolateral wings where GH cells predominated were far from these regions. These data suggest that the anatomical pattern of the blood supply may account in part for the spatial distribution of PRL and GH cells.

Animals↗
PubMed1988

Sex difference in prolactin and growth hormone cells in mouse adenohypophysis: stereological, morphometric, and immunohistochemical studies by light and electron microscopy.

PRL and GH cells in the adenohypophysis of adult mice were studied with immunohistochemistry and stereological morphometry by light and electron microscopy. We compared findings for males and females. In female mice, most PRL-immunoreactive cells (43% of all parenchymal cells) and most GH-immunoreactive cells (33% of all parenchymal cells) were classical PRL cells (type I PRL cells) or GH cells (type I GH cells), respectively. Besides these classical types of cells, we found PRL- and GH-immunoreactive (type II PRL and GH) cells that contained small (approximately 100-200 nm in diameter) and round secretory granules. However, in female mice type II PRL or GH cells accounted for less than 3% of all parenchymal cells, as was also true for type II GH cells in the males. The percentages of type I and type II PRL cells in male mice were about the same (approximately 10% of all parenchymal cells). Only a few mammosomatotropes (0-0.6% of all parenchymal cells) were found in the mouse adenohypophysis of either sex. All mammosomatotropes were type II cells; none were PRL or GH cells of the classical type. This immunohistochemical study confirmed our previous findings by conventional electron microscopy that there are marked sex differences in the proportions of PRL and GH cells in the adult mouse adenohypophysis; PRL cells are more abundant in the female mice, and GH cells are more abundant in the males.

Animals↗
PubMed1987

Giant mitochondria in acute lymphocytic leukemia.

Giant mitochondria were observed in 2 cases among 28 cases of ALL by electron microscopy. The cristae of the giant mitochondria in the leukemic cells were irregularly arranged, decreased in number, and formed concentric circles. Several morphological abnormalities were also observed in the normal mitochondria. Morphometric analysis of the mitochondria in the 2 patients disclosed that the sizes of mitochondria were well distributed from small to large and thus, the mitochondria could not be divided into different populations. Also, there were no clear differences in the distribution of shape between normal and giant mitochondria. These results suggest that the giant mitochondria were derived from normal mitochondria. Since they were observed before the initial treatment, they did not developed as a result of drug action.

Adolescent↗
PubMed1987

Differentiation of blast cells from a Down's syndrome patient with transient myeloproliferative disorder.

A male neonate with Down's syndrome and congenital myeloproliferative disorder was studied. His blood picture showed the unique coexistence of leukocytosis with matured cells and a large number of blast cells. The in vitro proliferation and differentiation of blast cells into various lineages in the presence of phytohemagglutinin-stimulated leukocyte conditioned medium (PHA-LCM) was examined by using a liquid culture and a methylcellulose culture system. The differentiation of blast cells into myeloid cells was confirmed by specific cytochemical stainings, electron microscopy, and an immunologic study. No specific factors in the plasma of the patient promoted the proliferation or differentiation of blast cells. The cellular composition of colonies grown in methylcellulose culture from single blast cells was studied by a micromanipulation technique. High plating efficiency was observed. Of 136 cultures, 78 showed colony growth. Half of the blast cells were colony-forming cells that could proliferate and differentiate into basophils, neutrophils, eosinophils, macrophages, and erythrocytes in the presence of PHA-LCM. Using the blast cells with a high differentiation capacity to the basophil pathway, we studied the effect of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF). Recombinant GM-CSF support neutrophils, eosinophils, and macrophages but not typical basophils. These findings of the cell differentiation of blast cells into various kinds of cells in vitro were in agreement with the finding of neutrophilia, eosinophilia, basophilia, and thrombocythemia in this patient.

Cell Differentiation↗
PubMed1986

Quantitative evaluation of leukemic mitochondria with a computer-controlled image analyzer.

Mitochondria from 25 patients with acute lymphoblastic leukemia (ALL) and 25 patients with acute myelogenous leukemia (AML) were compared in terms of their number, area, and shape index using a computer-controlled image analyzer. The number of mitochondria was greater in the AML than in the ALL patients. However, their size, as measured in electron micrographic profiles was similar in the two groups, in disagreement with conventional reports that mitochondria are small in granulocytes but large in lymphocytes. Two ALL patients had giant mitochondria. The mitochondria of the ALL cells were more irregular than those of the AML cells, and furthermore, within the ALL group, the degree of the irregularity was greater in those with a poor prognosis than in those in longstanding remission. The number of mitochondria was significantly greater in B-cell ALL than in null cell and T-cell ALL.

Bone Marrow↗