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Biomedical subjects

M Morishima

Publications and source records attributed to M Morishima.

At least 19 recordsLinked to original sources
PubMed1995

Morphological observations on the pathogenetic process of transposition of the great arteries induced by retinoic acid in mice.

BACKGROUND: The pathogenesis of complete transposition of the great arteries (TGA) is still controversial because useful animal models have not been established. We previously reported that all-trans retinoic acid induced complete TGA at a high proportion in mice. The aim of the present study was to clarify the morphogenesis of the cardiac outflow tract in the retinoic acid-treated embryos destined to develop TGA. METHODS AND RESULTS: We first examined the morphology of TGA in mouse fetuses treated with retinoic acid to establish an animal model of TGA (experiment 1) and then examined the retinoic acid-treated embryonic hearts by means of ink injection and histology (experiment 2). All mouse fetuses and embryos showed visceroatrial situs solitus and d-ventricular loop. In experiment 1, among 45 embryos treated with retinoic acid 70 mg/kg at day 8.5 of gestation, 35 (78%) had TGA and 3 (6.7%) had a double-outlet right ventricle with a subpulmonary ventricular septal defect. In experiment 2, all hearts already exhibited d-loop at gestation day 8.5. At gestation day 9.5, conus swellings, composed of acellular cardiac jelly, where hypoplastic, and the conotruncal cavity was nonspiral or tubular. At gestation day 11.0, aberrant conus swellings located anteroposteriorly to give a straight orientation to the conotruncal cavity. At gestation day 12.0, side-by-side great arteries were transposed in that the aorta arose from the right ventricle and the pulmonary artery arose above the interventricular foramen. CONCLUSIONS: These results suggest that a reproducible animal model of TGA can be produced in mice by treatment with retinoic acid; that there was no loop anomaly, such as an A-loop or L-loop, in our model; and that hypoplasia of the conus swellings appears to be the primary event leading to TGA.

Animals↗
PubMed1995

Hemodynamics and ventricular function in the day-12 rat embryo: basic characteristics and the responses to cardiovascular drugs.

We investigated the basic characteristics of the rat embryonic circulation and also looked at the hemodynamic effects of alpha- and beta-agonists, digitalis, and atrial natriuretic peptide, using a modified organ culture system in which the embryo was placed in oxygenated Hanks' balanced salt solution, blood pressure was measured by a servo-null micropressure system, and blood flow pattern was obtained by a 20-MHz pulsed Doppler velocity meter. The peak pressure was 0.5 +/- 0.04 (SEM) mm Hg at the atrium (n = 6), 2.3 +/- 0.10 mm Hg at the ventricle (n = 15), 1.6 +/- 0.03 mm Hg at the truncus (n = 7), and 1.0 +/- 0.05 mm Hg at the umbilical artery (n = 21). There was a pressure drop from the ventricle to the truncus and then a smaller pressure decrease to the umbilical artery. The atrial a-wave was 20% of ventricular pressure and ventricular inflow blood flow pattern showed very low early-to-late filling ratio, indicating that the ventricle was stiff. These findings were essentially the same as in the chick embryo. We recorded the ventricular image by using a high-speed video system with a frame rate of 200/s, and the ventricular pressure-area loop showed a triangular shape with short isovolumetric phases, which was different from that of the chick embryo at a similar stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Visceroatrial heterotaxy syndrome in the NOD mouse with special reference to atrial situs.

Following the onset of diabetes mellitus (DM) in the NOD mouse, diabetic dams have many offspring with severe anomalies, especially with visceroatrial heterotaxy syndrome. The purpose of the present study is to analyze this syndrome with special reference to atrial situs. The fetuses from a colony of NOD mice in our laboratory were divided into two study groups: Group A included fetuses from dams before the onset of DM and group B included fetuses from dams with overt DM before day 8 of pregnancy. The fetuses which had cardiac anomalies with viscero-atrial heterotaxy were classified into four subtypes according to the atrial morphology, i.e., "incomplete situs solitus" (or solitus-like), "incomplete situs inversus" (inversus-like), right isomerism, and left isomerism. Group A (671 fetuses) included only one case with right isomerism (0.15%) and four cases with left isomerism (0.6%). Group B (158 fetuses) had 57 fetuses with heterotaxy syndrome (36.1%), including 20 cases with solitus-like, 6 with inversus-like, 30 with right isomerism, and one with left isomerism. A tendency for right isomerism to occur was found in fetuses with solitus-like and inversus-like anomalies. These results show that the maternal DM in this mouse had an influence upon the morphological mechanism determining right isomerism of visceroatrial heterotaxy syndrome. Thus this syndrome in the NOD mouse is equivalent to asplenia in humans, and it may be useful in elucidating the mechanism of the human syndrome.

Animals↗
PubMed1991

Effects of environmental hyperthermia on cardiovascular function in the rat embryo.

Effects of hyperthermia on the cardiovascular function of the mammalian embryo have not been well defined. The effect of hyperthermia on the blood flow and umbilical artery blood pressure was studied in rat embryos at gestational d 12 by using a method developed in our laboratory. When the temperature was changed from 37 to 42 degrees C, the heart rate increased by 15% (n = 33). Mean umbilical artery blood pressure, measured by a servo-null micropressure system, decreased from 0.64 +/- 0.05 to 0.53 +/- 0.04 mm Hg (n = 11), whereas blood flow velocity at the conotruncus, a measure of cardiac output, obtained by a 20-MHz pulsed Doppler ultrasound flowmeter, increased by 36 +/- 11% (n = 11). Mean umbilical artery blood flow increased by 66 +/- 13% (n = 11) and its vascular resistance, calculated by ratio analysis, decreased from 3.7 (median) to 1.8 units. These changes returned to baseline values when the temperature was returned to 37 degrees C. The change in blood pressure was different from that seen in the chick embryo, indicating that there is species difference in the hemodynamic effect.

Animals↗
PubMed1990

[Determination and clinical significance of anti-idiotypic antibody--in model experiments of thyroglobulin and TSH].

Anti-idiotypic (anti-ID) antibody in test serum was determined by the direct binding assay using 125I-anti-human thyroglobulin (hTg). Several positive cases were found in Graves' disease and thyroiditis chronica. Positive anti-ID antibodies could be classified into two types. Type 1 showed the positive anti-hTg antibody and high Tg levels by RIA using double antibody method. Type 2 showed the positive anti-hTg antibody but low Tg levels by RIA. The binding of 125I-hTg to anti-hTg antibody was displaced by anti-ID antibody in type 1, but was not anti-ID antibody in type 2. A case of coexistence of autoantibody to hTSH and auto-anti-ID antibody to anti-hTSH antibody was found. She showed normal thyroid function (T4, T3), but TSH level showed discrepancy by different assay methods. Both autoantibodies for hTSH and for anti-hTSH antibody were demonstrated by the reaction of patient's antibody with both 125I-hTSH and 125I-anti-hTSH (MoAb). These two autoantibodies belong to the polyclonal IgG. The autoantibody for hTSH recognized only the beta-subunit of hTSH. Neither stimulating type of TSH receptor antibody (TRAb) nor blocking type of TRAb interfered with the binding of patient's anti-ID to 125I-anti-hTSH. This binding reaction could be inhibited by the unlabeled hTSH. This anti-ID might represent the internal image of the non-biological active site of TSH molecule, because of absence of thyroid stimulating activity. These anti-ID antibodies may provide evidence supporting a network theory of the immune system.

Adolescent↗
PubMed1986

[Correlation of LH and prolactin pulses in normoprolactinemic women with ovulatory disturbances and variation of LH and FSH pulses and secreting capacity by administration of bromocriptine in the same cases].

The difference between prolactin (PRL) basal levels on separate days in the 6 normoprolactinemic women--one case with an anovular cycle and 5 cases with 1 degree amenorrhea--among 14 normoprolactinemic women with ovulatory disturbances, showed significantly variation over 13 ng/ml within the normal range of the PRL basal level. PRL pulse frequencies of the same cases from 0900 h. to 1400 h. increased slightly compared with follicular phase. At the same time, the PRL pulse amplitudes were significantly higher than in the follicular phase but significantly lower than the PRL pulse amplitudes in hyperprolactinemic women. The net increase in PRL to TRH in the 6 cases was over 100 ng/ml. When the PRL net increase to TRH was over 100 ng/ml in normoprolactinemic women with ovulatory disturbances, the case is regarded as latent hyperprolactinemia. And 1 or 2 may be latent hyperprolactinemic syndrome. The LH/FSH basal level and delta LH/delta FSH to LH-RH before administration of bromocriptine increased in these cases compared with the follicular phase. During the administration of bromocriptine, the ratios decreased and approached the ratio in the follicular phase. The effect of clomid was improved by increased E2 in these cases.

Amenorrhea↗
PubMed1983

Percutaneous transluminal angioplasty (PTA) as an adjunct in vascular trauma: case report.

An iliac stenosis causing a pressure gradient of 70 mm Hg proximal to repair of a traumatically divided superficial femoral artery was relieved by percutaneous transluminal balloon angioplasty (PTA). Though the magnitude of the accompanying crush injury led to massive muscle necrosis and ultimately necessitated mid-thigh amputation, the arterial repair remained patent.

Angioplasty, Balloon↗