Telepathology and Cytology in Kyoto, JAPAN, to Support Regional Medicine, with Special References to Their Need, Accuracy and Cost.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
M Morishima
Publications and source records attributed to M Morishima.
Amino acid substitutions in the first transmembrane domain (TM1) of P-glycoprotein that alter substrate specificity.
Recently, we showed that the amino acid at position 61 in TM1 of human P-glycoprotein is important in deciding the substrate specificity of this protein. In this work, we investigated whether the amino acids other than His61 in TM1 of P-glycoprotein are also essential in the function of this protein. Nine amino acids residues, from Ala57 to Leu65 in TM1, were independently substituted to Arg, and analyzed the drug resistance of cells stably expressing each of these mutant P-glycoproteins. The mutant P-glycoproteins Ile60 --> Arg, His61 --> Arg, Ala63 --> Arg, Gly64 --> Arg, and Leu65 --> Arg were normally processed and expressed in the plasma membrane. Substrate specificities of mutant P-glycoproteins Gly64 --> Arg and Leu65 --> Arg were quite different from that of the wild type, and similar to that of the His61 --> Arg mutant, while the Ile60 --> Arg and Ala63 --> Arg mutant P-glycoproteins showed similar substrate specificities to that of the wild-type P-glycoprotein, suggesting that not only the amino acid residue at position 61 but also those at position 64 and 65 are also important in deciding the substrate specificity of P-glycoprotein. These three amino acids His61, Gly64, and Leu65 would form a compact region on an alpha-helix arrangement of TM1. These results suggest that a region consisting of His61, Gly64, and Leu65 in TM1 would participate in the formation of the recognition site for substrates of P-glycoprotein.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Alteration of substrate specificity by mutations at the His61 position in predicted transmembrane domain 1 of human MDR1/P-glycoprotein.
In CFTR, a member of the ABC superfamily and a chloride channel, amino acid substitutions in its transmembrane domains 1 and 6 (TM1, TM6) have been reported to modulate the anion selectivity or ion conductance of the ion channel. In P-glycoprotein, no amino acid substitution in TM1, but some in TM6, have been reported to modify the substrate specificity of this protein. In this work, we demonstrated the involvement of His61, which is in the middle of the predicted TM1, in the function of P-glycoprotein. His61 was replaced by all other amino acid residues, and each of the mutant cDNAs was introduced into drug-sensitive human carcinoma cells, KB3-1. The drug-resistance profile of cells stably expressing each mutated P-glycoprotein was investigated by comparing their relative resistance to vinblastine, colchicine, VP16, and adriamycin. The resistance to vinblastine was increased by replacing His61 by amino acids with smaller side chains, while it was lowered by replacing by amino acids with bulkier side chains. The reverse effect was observed for resistance to colchicine and VP16. The resistance to adriamycin was increased by replacing by amino acids with bulkier side chains except Lys or Arg, which have a basic side chain. We also showed that the replacement of His61 by Phe and Lys greatly impaired the efflux of calcein AM, while the replacement had no effect on the efflux of rhodamine 123. These results suggest that an amino acid residue at position 61 in TM1 is important in deciding the substrate specificity of P-glycoprotein.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Cardiac outflow tract septation process in the mouse model of transposition of the great arteries.
It has been reported that all-trans retinoic acid induces transposition of the great arteries (TGA) at 80-90% in ICR mice. The authors revealed that retinoic acid affects the initial formation of the conus cushions leading to a loss of spirality in the cardiac outflow tract. However, the aberrant process of septation has not been precisely defined. In this study, we observed the hearts of live embryos using a video system followed by scanning electron microscopic examination. First, we found that, in the retinoic acid-treated embryos, the proximal outflow tract cushions, in addition to hypoplasia and dysplasia, did not establish the continuity with the distal outflow tract cushions and could not contribute to the outflow septation. Second, the distal outflow tract did not rotate counter-clockwise, retaining the outflow septum anlage in the superoinferior position. Third, a tongue-like mesenchymal tissue had developed on the right anterior rim of the muscular interventricular septum and was incorporated into the interventricular septum. Altogether, these processes contributed to establishing a reversed relationship between the outflow septum anlage and the ventricular septum anlage. On the other hand, right-ward deviation of one or both of the distal outflow tract cushions, relative to the mesenchymal tissue, gave rise to variable degrees of overriding of the pulmonary artery orifice. We conclude that, due to hypoplasia and dysplasia of the proximal outflow tract cushions and lack of distal outflow tract rotation, the outflow septum anlage took an inverted relationship with the ventricular septum anlage. Various types of rightward shift of the outflow tract cushions produced a morphological spectrum of TGA-type cono-truncal anomalies.
Animals↗
Distribution of fibronectin, type I collagen, type IV collagen, and laminin in the cardiac jelly of the mouse embryonic heart with retinoic acid-induced complete transposition of the great arteries.
BACKGROUND: In the mouse model of complete transposition of the great arteries (TGA) produced by all-trans retinoic acid (RA), parietal and septal ridges in the outflow tract (OT) are hypoplastic. At first, these ridges are generated by an expanded cardiac jelly (mainly myocardial basement membrane). Thereafter, endothelial cells delaminate and invade into the adjacent cardiac jelly to form endocardial cushion tissue (formation of cushion ridge). During cushion tissue formation, basement membrane antigens play an important role in the regulation of this endothelial-mesenchymal transformation. METHODS: To examine whether the myocardial basement membrane components are altered in the RA-treated heart OT, immunohistochemistry for fibronectin, type I collagen, type IV collagen, and laminin was carried out in mouse embryonic hearts at 9.5 and 10.5 ED (embryonic day; vaginal plug = day 0) with or without prior exposure to RA. RESULTS: Particulate/fibrillar fibronectin and fibrillar type I collagen were observed in the thick cardiac jelly of the control heart at the onset of mesenchymal formation. In the RA-treated heart, an intermittent patchy staining for fibronectin and a sparse distribution of type I collagen were observed in the thin cardiac jelly. Laminin and type IV collagen were distributed continuously on the basal surface (layer adjacent to the basal plasma membrane) of endocardium and myocardium in both control and RA-treated hearts. CONCLUSIONS: The alterations in the antigens of the myocardial basement membrane (cardiac jelly) may be responsible for the hypoplasticity of parietal and septal ridges that characterizes RA-induced TGA morphology. This may be one of the reasons why mesenchymal cell formation is inhibited in the RA-induced TGA.
Animals↗
How does P-glycoprotein recognize its substrates?
We review how P-glycoprotein recognizes a wide variety of compounds and how it carries its substrates across membranes. Amino acid substitutions that affect the substrate specificity of P-glycoprotein have been found scattered throughout the molecule. In particular, some amino acid residues in the putative transmembrane domain (TM) 1 together with TM5-6 and TM11-12 may help to govern substrate specificity. The features that substrates for P-glycoprotein share are also discussed. The amphipathy of a substrate may decide whether the substrate can be intercalated into the lipid bilayer of the membrane. In addition, only certain molecular volumes and tertiary structures may make it possible for the substrate to fit into the substrate-binding site(s) of P-glycoprotein.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Altered distribution of collagen type I and hyaluronic acid in the cardiac outflow tract of mouse embryos destined to develop transposition of the great arteries.
Complete transposition of the great arteries (TGA) is inducible by treatment with all-trans retinoic acid in the ICR mouse. In this model, hypoplasia and dysplasia of the proximal outflow tract cushion tissue lead to non-spiral septation. In order to evaluate the effect of retinoic acid on the extracellular matrix of the cardiac outflow tract, we examined the distribution of collagen type I and hyaluronic acid, immunohistochemically, on days 8-9 of gestation. In controls, collagen type I fibrils ran mainly in a radial direction, extending towards the endocardium in the cardiac jelly of the proximal outflow tract. Also, a pair of longitudinal fiber bundles were formed stretching to the distal outflow tract. As for hyaluronic acid, intense staining was observed in the submyocardial and intermyocardial space of the outer curvature of the heart. On the other hand, in retinoic acid-treated embryos, the submyocardial radial fibrils or longitudinal fiber bundles of collagen type I were diminished, and irregular and dense deposits of collagen type I were observed along the endocardium. Furthermore, hyaluronic acid showed a loss of differential localization between the outer and inner curvature. Instead, irregular and intense staining was observed uniformly along the outflow myocardium. Thus, retinoic acid appeared to have perturbed the differentiation in the proximal outflow tract causing an altered organization of multiple extracellular matrix molecules, including collagen type I and hyaluronic acid, which led to an abnormal molecular network of the cardiac jelly in the cardiac outflow tract, abnormal septation and, further, to TGA or TGA-type anomalies.
Animals↗
Influence of genetic and maternal diabetes in the pathogenesis of visceroatrial heterotaxy in mice.
The NOD mouse is known as a spontaneous model of insulin-dependent diabetes mellitus. Fetuses in this strain present anomalies of the viscera, and the incidence increases in fetuses from dams with clinically manifested diabetes. To examine the role of maternal diabetes and the genetical influence in inducing heterotaxy, NOD dams were mated with males of the ICR strain (the original strain of the NOD) and with C57BL/6J sires (not genetically related to the NOD). The frequency of visceroatrial heterotaxy in fetuses from diabetic dams varied with the fetal genotype, being 65% (33/51) in NODxNOD (dam X sire, respectively), 24% (12/50) in NODxICR, and 7% (4/57) in NODxC57BL/6J. The cases with heterotaxy showed a tendency toward right isomerism of the viscera and had severe cardiac defects, such as endocardial cushion defect and double-outlet right ventricle or transposition of the great arteries. The fetal body weight from diabetic dams in each mating was lower than that from non-diabetic dams (P < 0.05), suggesting that maternal diabetes, rather than abnormal situs, is the main determinant for decreased fetal growth. These findings demonstrate that the liability to heterotaxy induced by maternal diabetes is influenced by the fetal genotype.
Abnormalities, Multiple↗
Hypoplasia of cushion ridges in the proximal outflow tract elicits formation of a right ventricle-to-aortic route in retinoic acid-induced complete transposition of the great arteries in the mouse: scanning electron microscopic observations of corrosion cast models.
BACKGROUND: The major morphologic change associated with retinoic acid (RA)-induced complete transposition of the great arteries (TGA), a congenital malformation of the heart, was investigated in a mouse model in which TGA was found in 80% of surviving fetuses. METHODS: Corrosion casts of embryonic hearts with or without prior exposure to retinoic acid were observed under a scanning electron microscope. RESULTS: In control hearts, indentations caused by expanded parietal and septal ridges in the outflow tract established right ventricle-to-left ventral pulmonic and left ventricle-to-right dorsal aortic routes before the aorticopulmonary septum completion. In RA-treated hearts, indentations of proximal regions of the parietal and septal ridges were small in the proximal outflow tract, whereas those in the distal regions developed well. These morphological features in the RA-treated hearts elicited right ventricle-to-right ventral aortic and left ventricle-to-left dorsal pulmonic routes in the TGA morphology. CONCLUSIONS: Hypoplasticity of the proximal regions of parietal and septal ridges in the outflow tract is one of the primary morphological abnormalities of the RA-induced TGA.
Animals↗
Pathological study of Japanese quail embryo with acid alpha-glucosidase deficiency during early development.
A pathological study was performed on the tissues of 11 Japanese quail embryos with type II glycogen storage disease (GSD II) between incubation day (ID) 3 and ID 15. Accumulation of glycogen in vacuoles derived from lysosomes was first seen in cardiac muscle at ID 3, in liver at ID 5, in wing muscle at ID 7, and in pectoral muscle at ID 10. The number and size of the glycogen vacuoles gradually increased during development, especially in cardiac muscle. Cytoplasmic glycogen particles, showing the same density as membrane-enclosed glycogen particles, were first seen as masses in cardiac muscle at ID 3, in liver at ID 5, in pectoral muscle at ID 10, and in wing muscle at ID 15. The area of cytoplasm occupied by the glycogen particles increased during development. Myofibrillar degeneration was not seen, although myofibrils appeared in disarray in the early stages, as in normal embryos. This is the first study of the development of embryonic tissues of Japanese quails with GSD II. GSD II in the Japanese quail appears to be clinically analogous to the human late (juvenile)-onset disease, although the disorder starts at very early stages in quail embryos. Therefore, Japanese quails with GSD II can provide a model for elucidating the pathogenetic process of human GSD II.
Animals↗
Inhibition of outflow cushion mesenchyme formation in retinoic acid-induced complete transposition of the great arteries.
OBJECTIVE: Endocardial cushion tissue formation, the primordia of valves and septa, is a critical event in cardiac morphogenesis. Maternally administrated all-trans retinoic acid is known to induce complete transposition of the great arteries (TGA) in the mouse embryo. To address the mechanisms of TGA, the effect of retinoic acid on cushion tissue formation was examined. METHODS: Using a three-dimensional collagen gel culture model, we performed various types of endothelial-mesenchymal transformation assays of co-cultured endocardium with myocardium obtained from 9.5-day mouse embryonic hearts. In vivo immunohistochemical detections of extracellular matrices, fibronectin and type I collagen, were also performed. RESULTS: Endothelial-to-mesenchymal transformation at the onset of cushion tissue formation was suppressed in the outflow tract of embryos exposed to retinoic acid in culture. This inhibitory effect of retinoic acid was spatially restricted to the outflow tract and reversed by treatment with embryonic myocardial conditioned medium enriched in extracellular inductive molecules. Mesenchyme formation in the outflow tract was inhibited at a lower concentration of retinoic acid (10(-10) mol/l) than that which inhibited the atrio-ventricular canal (10(-7) mol/l) in culture. The fibronectin and type I collagen depositions in pre-migratory outflow tract cardiac jelly in retinoic acid-treated embryonic heart were reduced compared to those in the control. CONCLUSIONS: Exogenously applied retinoic acid inhibits outflow tract cushion mesenchyme formation in the embryonic heart with TGA. It is suggested that retinoic acid inhibits the expression of extracellular matrices and inductive molecules synthesized by myocardium in the outflow tract.
Animals↗
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↗
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↗
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↗
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↗
[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↗
[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↗
[The distribution of oral Staphylococci from wild large Japanese field mice living in various areas].
Explore the source record for details and available documents.
Animals↗