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Biomedical subjects

M Yasuda

Publications and source records attributed to M Yasuda.

At least 469 records · Page 26Linked to original sources
PubMed1986

Changes in the subepithelial mesenchymal cell process meshwork in developing facial prominences in mouse embryos.

We examined temporal and spatial changes in the subepithelial mesenchymal cell process meshwork (CPM) in normally developing medial (MNP) and lateral nasal prominences (LNP) in mouse embryos by light and scanning electron microscopy. Marked changes were found only in the MNP during the fusion of the MNP and LNP. The CPM density in the prospective fusion area of the MNP gradually increased as the epithelial surfaces approached each other, attained its maximum just before contact, and decreased after contact. The CPM density in the prospective fusion area of the LNP changed only slightly even when the epithelial surfaces approached each other. The increase in CPM density paralleled that in the density of mesenchymal cell bodies. The LNP grew more actively toward the line of fusion than did the MNP during the progressive fusion of the two prominences. A larger number of fusion-associated epithelial morphological changes--the appearance of superficial protruding cells and cell degeneration--occurred in the MNP than in the LNP. These findings suggest that the increased CPM density is closely related to the growth of the facial prominences and the fusion-associated epithelial morphology and that the CPM plays an important role in the epithelial-mesenchymal interaction during the formation of the upper lip and primary palate.

Animals↗
PubMed1986

[Experimental chemotherapy of germ cell tumor heterotransplanted to nude mice].

While the treatment of ovarian cancer has made remarkable progress in recent years, the chemotherapy of ovarian germ cell tumor has not as yet been fully established and remains to be improved. We investigated the effectiveness of a single-agent therapy with Vincristine (VCR), Actinomycin D (ACD), and Cyclophosphamide (CPM) against a human undifferentiated dysgerminoma's cell line (JOHYL-1) with the following results. The ratio of the number of viable cells to the total cell population treated for JOHYL-1 cells of ascitic type was 70% with VCR, 58% with CPM and 25% with ACD; hence the efficacy on this malignant cell line was the greatest with ACD followed by VCR and CPM in that descending order. Notably with CPM, a striking antitumor effect was observed from 48 to 24 hours after treatment. The L.I. attained a peak at 24, 18 and 30 hours, respectively, after treatment with VCR, ACD and CPM. The M.I. was as high as a little more than 6% at 36 hours after treatment with VCR. There also was noted a shift in the cell cycle with any of the test drugs. Morphological changes observed in the cell were most obvious with ACD followed in order by VCR and CPM. LDH & isozyme pattern: In these respects there were no striking differences among the three drugs, even though the total enzyme activity was somewhat higher with VCR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Experimental study of the mechanism of peritoneal dissemination--with special reference to scanning electron microscopic observations].

Most malignant ovarian tumors metastasize by peritoneal dissemination and have a poor prognosis. Few studies have been made to determine how free ovarian tumor cells act on the peritoneum and become lodged and proliferate therein and much still remains to be clarified concerning this issue. In the present study, we transplanted 2 X 10(6) cells of JOHYL-1 strain established from an atypical dysgerminoma into the peritoneal cavity of nude mice observed serially morphological changes in the peritoneum resulting from tumor cell dissemination both by light microscopy and SEM. The findings thus obtained may be summarized as follows: From 5 to 7 days after intraperitoneal transplantation of tumor cells, mesothelial cells of the peritoneum began to swell, with the intercellular boundaries becoming distinct. Microvilli of the mesothelial cells increased in number, forming a mesh-like structure, and in some places were found to be in direct contact with a tumor cell. From 10 days after tumor cell transplantation onwards the mesothelium showed enlarged intercellular spaces in some places, and at these sites tumor cells were seen to have adhered. On other sites mesothelial cells were being partially lost. From 11 days after being transplanted, the tumor cells started proliferating and infiltrating in the muscle layer. Concerning the site of tumor cell implantation, evidence was obtained showing that tumor cells adhered to intercellular spaces of mesothelial cells, and/or in defects formed on connective tissue by a loss of mesothelial cells. The study thus demonstrated a salient usefulness of the JOHYL-1 ascites type cell line, with a reliably great capacity for growth in vivo, as an experimental model for the study of peritoneal dissemination of tumor cells.

Animals↗
PubMed1985

Pathogenesis of the mouse forelimb deformity induced by acetazolamide: an electron microscopic study.

Scanning electron microscopic observations after removal of the epidermis from developing limb buds reveal a fine mesenchymal cell process meshwork (CPM). The relationship between apical ectodermal ridge (AER) development and CPM density was investigated and related to the postaxial reduction deformities induced by acetazolamide (AA). AA was given orally to pregnant mice at 9 A.M. and 4 P.M. of day 9 and 9 A.M. of day 10 (VP = 0) in a dose of 1,000 mg/kg. Forelimb ectrodactyly, especially on the right, was the most common deformity observed. Scanning electron microscopic observations showed that the AER in AA-treated right forelimb buds did not extend postaxially as far as that in controls. The postaxial region with the hypoplastic AER became defective. Scanning and transmission electron microscopic observations revealed that in control and treated right forelimb buds, the CPM underneath the typical AER was sparser than that underneath the dorsal or ventral non-ridge epidermis. However, in treated right forelimb buds, the CPM underneath a hypoplastic AER was denser than that underneath the normal AER. These findings suggest that AA-induced deformity results from a disturbance of the AER-mesenchymal interactions.

Abnormalities, Drug-Induced↗
PubMed1985

An adult case of arrhythmogenic right ventricular dysplasia.

A forty-year-old man was admitted to our hospital because of dizziness, palpitations and an oppressive feeling in the precordium. Physical examination was normal. A chest roentgenogram revealed mild cardiomegaly and the electrocardiogram showed ventricular tachycardia of a left bundle branch block configuration which was terminated by the intravenous injection of procainamide. During sinus rhythm the electrocardiogram showed incomplete right bundle branch block, PQ prolongation and inverted T waves in leads V1 through V3. Two-dimensional echocardiography revealed only moderate right ventricular dilatation. Right ventricular angiography showed severe right ventricular dilatation and hypokinesis of the right ventricular apex and pulmonary artery infundibulum. From these characteristics signs we concluded that this adult patient had arrhythmogenic right ventricular dysplasia (ARVD), suggesting that this condition is not confined to children but may occur in adults as well.

Adult↗
PubMed1985

[Cardiovascular hemodynamics in patients with essential hypertension during multi-stage exercise].

We investigated cardiovascular hemodynamics in patients with essential hypertension at rest and during exercise. Eight patients with borderline hypertension (Group B), 18 patients with sustained hypertension, and 10 normotensive subjects (Group N) were studied. Patients with sustained hypertension were categorized in two groups; 10 patients without cardiac hypertrophy (Group NH), and eight patients with cardiac hypertrophy (Group HH). To assess the cardiovascular hemodynamics, M-mode echocardiograms, electrocardiograms and carotid pulses were recorded during multistage exercise using a supine bicycle ergometer. Blood pressure was measured simultaneously by the cuff method. At rest, isovolumic relaxation times (IRT) in Groups NH and HH were significantly prolonged as compared with that of Group N. The IRT of Group HH was significantly prolonged as compared with that of Group NH (Group N: 0.06 +/- 0.01 sec, Group B: 0.07 +/- 0.01 sec, Group NH: 0.08 +/- 0.02 sec, Group HH: 0.09 +/- 0.01 sec, respectively). Only the atrial filling fraction of Group HH was significantly increased over that of Group N (Group N: 25.6 +/- 12.1%, Group B; 30.0 +/- 8.1%, Group NH: 27.9 +/- 11.3%, and Group HH: 41.4 +/- 13.1%, respectively). The total peripheral vascular resistance (TPR) in Groups NH and HH was significantly increased over that of Group N (Group N: 1600 +/- 224 dyne/sec/cm-5, Group B: 1704 +/- 465 dyne/sec/cm-5, Group NH: 2370 +/- 608 dyne/sec/cm-5, and Group HH: 3290 +/- 1598 dyne/sec/cm-5, respectively). There was no significant difference in the cardiac index, ejection fraction or heart rate among all groups at rest and during exercise. However, the difference between TPR at rest and TPR at a load of 75 watt (delta TPR) was increased in Groups NH and Group HH over Group N (Group N: 558 +/- 166 dyne/sec/cm-5, Group B: 614 +/- 336 dyne/sec/cm-5, Group NH: 883 +/- 415 dyne/sec/cm-5, and Group HH: 1306 +/- 774 dyne/sec/cm-5, respectively). From these findings, we concluded that there is early diastolic left ventricular dysfunction in Groups NH and HH, and that the degree is more distinct in Group HH. It seems that systolic left ventricular function of both groups is normal during moderate exercise loads, and marked reduction of the TPR in both groups during exercise may be caused by marked peripheral vascular dilatation.

Adult↗
PubMed1985

[Left ventricular function in essential hypertension during isoproterenol infusion].

The left ventricular function of 23 patients with essential hypertension was investigated during infusion of isoproterenol (ISP). These patients consisted of 13 without cardiac hypertrophy (Group NH) and 10 with cardiac hypertrophy (Group HH). Ten normotensive subjects served as normal controls. To assess left ventricular functions, M-mode echocardiograms were recorded at rest and after ISP infusion for 5 minutes (0.005 and 0.01 microgram/kg/min). There were no significant differences in peak negative dD/dt in all groups at rest. But peak negative dD/dt of Group HH significantly decreased after an infusion of 0.005 microgram/kg/min ISP (Group N: 3.43 +/- 0.69, Group NH: 3.15 +/- 0.61, and Group HH: 2.49 +/- 0.48 cm/sec, respectively). The peak negative dD/dt of Group HH was also significantly decreased after a dose of 0.01 microgram/kg/min. Among all patients with hypertension, peak negative dD/dt correlated inversely with left ventricular mass (LVM) after the infusion of ISP (0.005 microgram/kg/min: r = -0.64, p less than 0.001, 0.01 microgram/kg/min: r = -0.68, p less than 0.001). The peak positive dD/dt of Group HH was significantly decreased only when compared with that of Group N at rest (Group N: 3.15 +/- 0.75, Group NH: 3.02 +/- 0.86, and Group HH: 1.92 +/- 0.68 cm/sec, respectively). The difference between the peak positive dD/dt of Group HH and that of Group N was more prominent after the infusion of ISP than at rest. Among all patients with hypertension, the peak positive dD/dt was inversely related to LVM at rest (r = -0.64, p less than 0.002). There was a similar relation between the two indexes after the infusion of ISP. Peak positive dD/dt was related to peak negative dD/dt after a dose of 0.01 microgram/kg/min in Group HH (r = 0.67, p less than 0.05). There was no significant difference in heart rate, change in blood pressure, or total peripheral vascular resistance after the infusion of ISP. It is concluded that diastolic left ventricular dysfunction and latent systolic left ventricular dysfunction are related to increased LVM in Group HH. It seems that after the infusion of ISP severe diastolic left ventricular dysfunction is related to latent systolic left ventricular dysfunction.

Adult↗