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Biomedical subjects

K Morimoto

Publications and source records attributed to K Morimoto.

At least 721 records · Page 40Linked to original sources
PubMed1980

Experimental approach to fibrous histiocytoma.

A transplantable tumor was produced in syngeneic mice inoculated with transformed bone marrow macrophages (28-12- and L-18 cell lines). The tumor composed of proliferative spindle cells was arranged in a storiform pattern, and was similar to that of human fibrous histiocytoma. Electron microscopically, the tumorous spindle cells had fibroblastic characteristics, while functionally, the tumor cells had histiocytic characteristics, and consisted of a transitional form between histiocytes and fibroblasts. We consider the spindle cells to be facultative fibroblasts. This finding is compatible with the hypothesis that fibrous histiocytoma is derived from histiocytes.

Animals↗
PubMed1980

Pharmaceutical studies of polyacrylic acid aqueous gel bases: absorption of insulin from polyacrylic acid aqueous gel bases following rectal administration in alloxan diabetic rats and rabbits.

The effect of gel preparation on the rate of absorption of a rectally administered insulin which was suspended in a polyacrylic acid aqueous gel base (0.1%, pH 6.5) was investigated in the alloxan diabetic rats and rabbits. The preparation was administered into the in situ rectal loop in rats or infused directly into the rectum in rabbits, and the change in the blood glucose level and plasma insulin value was taken as a measure to evaluate the rate of rectal absorption of insulin. The blood glucose lowering effect in both rats and rabbits was dose-dependent, namely, a slight effect was observed at 1 IU/kg followed by a significant effect with 3 and 5 IU/kg, and a sharp hypoglycemic effect was recorded with 10 IU/kg which lasted for 5 hr. The plasma insulin level exhibited a rapid increase at 30 minutes after the dosing of the insulin by the polyacrylic acid aqueous gel base. However, the plasma level quickly diminished in 1 hr. Contrary to our expectation, an addition of a non-ionic surfactant such as Tween 80 under pH 4--8 did not show further enhancement of the absorption. In an attempt to simulate a clinical condition in which insulin was given after a meal, the insulin gel was administered into the rectal loop in diabetic rats following the i.v. injection of glucose. A satisfactory result was obtained in which 5 IU/kg dose was able to suppress a rise in the blood glucose after the glucose loading.

Acrylic Resins↗
PubMed1980

Renal function, plasma renin, and spontaneous diuresis in an advanced stage of hypertension in rats.

Relationship of renal function and plasma renin level to a spontaneous diuresis in an advanced stage of hypertension was examined in the stroke-prone spontaneously hypertensive rats (SHRSP). For a comparison, it was also investigated in 2 kidney 1 clip (1CR) and 2 kidney 2 clip (2CR) models of renovascular hypertensive rats. The spontaneous diuresis was usually associated with an elevation of plasma renin level and an impairment of renal function in SHRSP and 1CR. In SHRSP, renal plasma flow showed an inverse correlation to the plasma renin level. The diuresis, however, is not prerequisite to the increase in plasma renin or to the renal impairment, since the latter changes were not always accompanied by diuresis. No correlations were found between these factors in 2CR. Remittent diuresis was observed in many 2CRs and 2 SHRSPs with normal renal function, indicating that renal damage underlies the continuous progression of the diuresis observed in most cases of SHRSP and 1CR. Both sodium and potassium balances tended to be negative in 1CR and 2CR in the diuretic phase, whereas potassium alone showed this tendency in SHRSP. The negative balances, if any, were not due to an excessive loss of the electrolytes but attributed mainly to a decrease in intake. The critical level of blood pressure for the spontaneous diuresis was highest in SHRSP and lowest in 1CR. It is probable that an interaction and cooperation between high blood pressure, impaired renal function and high plasma renin participate in the mechanism of the spontaneous diuresis during the development of malignant phase of hypertension of the rat.

Aldosterone↗
PubMed1980

Levels of astroprotein (an astrocyte-specific cerebroprotein) in cerebrospinal fluid of patients with brain tumors. An attempt at immunochemical diagnosis of gliomas.

Levels of astroprotein (an astrocyte-specific protein found in the cerebrum) were measured by radioimmunoassay in the cerebrospinal fluid (CSF) of 120 patients with intracranial diseases and eight control subjects. The astroprotein level was elevated (above 25 ng/ml) in 13 of 30 cases (43.3%) of glial tumors, nine of 57 cases (15.8%) of nongliomatous intracranial tumors, seven of 33 cases (21.2%) of non-neoplastic intracranial diseases, but in none of the eight control cases. In glioblastoma patients, CSF astroprotein was elevated in eight of 12 cases (66.7%), in three of them to a remarkable degree (above 500 ng/ml). The possible role of this test is briefly discussed, and the mechanism of increase of the astroprotein levels in the CSF considered.

Astrocytes↗
PubMed1980

Ion migration and inactivation in the calcium channel.

1. Calcium conduction has been studied under voltage clamp in isolated nerve cell bodies of Helix aspersa. A suction pipette method was used to produce internal perfusion and low access resistance to the cell's interior. 2. Ca current does not obey the independence principle and saturates with increasing extracellular Ca concentration. The effect is voltage-dependent. 3. The unit conductance for the Ca channel is between 10(-12) and 10(-13) S, values consistent with impeded conduction. 4. Inactivation is partly dependent upon an increase of intracellular Ca activity due to Ca current. However, a component remains after the increase in [Ca]i has been prevented with EGTA. 5. The Ca channel may have two open states or there may be two sets of Ca channels.

Animals↗
PubMed1980

[Cytochemical demonstration of 3 beta-hydroxysteroid dehydrogenase activity in human corpora lutea (author's transl)].

3 beta-hydroxysteroid dehydrogenase (3 beta-HDS) activity was demonstrated ultrastructurally in human corpora lutea obtained from the women aged 32-46 who were treated by the hysterectomy for various gynecological indications. The corpora lutea were removed from ovaries and cut into small pieces of 1 mm3. Specimens were incubated at 25 degrees C for 20 min. in the media containing dehydroepiandrosterone 0.6 mg, 0.1 M sodium citrate 0.3 ml, 5 mM potassium ferricyanide 1 ml, 30 mM copper sulfate 1 ml, N.A.D. 3.6 mg, sucrose 1.0 g and 0.1 M phosphate buffer (pH 7.2) 6 ml. For a control study, 1.5 mg cyanoketone (by the courtesy of Dr G.O. Pott), the specific inhibitor for 3 beta-HSD, was added to the media. The materials were fixed in 4% glutaraldhyde and 1% OsO4 and embedded in Epon 812. Electron dense reaction products of copper ferrocyanide were observed in smooth endoplasmic reticulum (sER) and in intercristal and outer space of mitochondria. In control studies, 3 beta-HSD activity were completely abolished. It is concluded that not only sER but also mitochondria has 3 beta-HSD activity in human corpora lutea. Furthermore, mitochondria seems to have capability to synthetize progesterone from cholesterol by itself.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

Comparative studies on the mutagenicity of 1,1'-ethylene-bis-(1-nitrosourea) and related compounds in Escherichia coli in relation to the formation of DNA interstrand cross-links.

The alkyl-nitrosourea-mediated formation of interstrand cross-links in E. coli DNA was studied by means of hydroxyapatite column chromatography. DNA interstrand cross-links were detected after treatment with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) but not after treatment with 1,1'-ethylene-bis(1-nitrosourea) (EBNU) or 1-methyl-1-nitrosourea (MNU). Thus, alkylation of DNA by EBNU seems to be monofunctional, as wtih MNU. The mutagenic and lethal activities of these three compounds were tested with a pair of Escherichia coli strains. EBNU gave slightly but significantly higher mutagenicity and lethality in a repairless (uvrA-) strain than in its parental strain and wild-type DNA repair, whereas CCNU and MNU showed equal mutagenicity and lethality in the two strains.

DNA, Bacterial↗
PubMed1980

[An ultrastructural study of capillaries of rabbit ovarian follicles during ovulatory process (author's transl)].

The observations that perifollicular capillaries of the ovary become engorged with prominent edema in the theca interna and externa around the time of ovulation, suggest a preovulatory increase in permeability of perifollicular capillaries. In order to obtain an ultrastructural evidence for this increased capillary permeability, we examined the perifollicular capillaries in the theca interna by using mature rabbit ovaries at various time intervals after the hCG injection for induction of ovulation. We observed a capillary engorgement at 9, 10, 12 hours after the hCG injection, most prominent at 9 hours, and edema in the pericapillary space at 10, 12 hours. Pinocytotic vesicles were seen through the all stages of follicular development and they did not show any significant changes in their size, number and distribution. Fenestrations were observed at 0, 3, 4, 6 hours after the hCG injection, most frequent at 4 hours. Intercellular gaps (500 approximately 1,200 A) between two endothelial cells were demonstrated at 10, 12 hours, and thrombocytes in these gaps were also noticed. The present observations suggest that increased permeability of perifollicular capillaries just prior to ovulation were mainly due to the formation of gaps between the endothelial cells.

Animals↗
PubMed1980

[An ultrastructural study of capillary permeability of rabbit ovarian follicles during ovulation using carbon tracer (author's transl)].

The observations that perifollicular capillaries of the ovary become engorged with prominent edema in the theca interna and externa around the time of ovulation, suggest a preovulatory increase in permeability of perifollicular capillaries. In previous study, we reported ultrastructural evidences which suggested the increased permeability of perifollicular capillaries just prior to ovulation. In this study, we further examined the perifollicular capillaries of rabbit ovary by using carbon particles as a tracer at various time intervals after the hCG injection for induction of ovulation. Pinocytotic vesicles exhibited no significant changes in size, number and distribution through all preovulatory stages. Carbon particles were not taken into them. Fenestrations were observed at 0,3,4,6 hrs after the hCG injection, most frequently at 4 hrs, but no carbon particles could penetrate them. Intercellular gaps between two adjacent endothelial cells began to be observed at 10 hrs after the hCG injection. Carbon particles passed through these gaps with staying inside the basement membrane (so-called intramural leaking). These observations indicated that the increased permeability of the perifollicular capillaries, just before ovulation, were due to intercellular gaps.

Animals↗
PubMed1980

Increase of sister chromatid exchanges and perturbations of cell division kinetics in human lymphocytes by benzene metabolites.

Benzene, which has been associated with human cancers, is metabolized to produce several major metabolites that could be responsible for the biological effects. Tests have now been carried out on human lymphocytes in culture to determine if benzene or its metabolites, phenol, catechol, and hydroquinone, induce cytogenetic changes and affect the cell cycle. The results indicate that benzene itself does not induce sister chromatid exchanges or affect cell cycle kinetics over a wide range of doses. Phenol has an effect only at very high doses. On the other hand, catechol is a potent compound that induces sister chromatid exchanges and delays cell division very readily. Hydroquinone is also potent, but less so than catechol. Thus, the formation of catechol and hydroquinone is the most likely cause of benzene toxicity.

Benzene↗