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Biomedical subjects

T Mitsui

Publications and source records attributed to T Mitsui.

At least 361 records · Page 20Linked to original sources
PubMed1985

Localization of periodate-Schiff reactive glycosaminoglycans in semi-thin sections embedded in GMA-Quetol 523-MMA--application of a method for correlative light and electron microscopy of identical sites.

A correlative light and electron microscope method in which semi-thin sections of embedded tissue were treated with periodate acid and Schiff's reagent (PAS) was used to determine the precise localization of PAS reactive substance. Small blocks of tissue specimens were fixed with aldehyde mixtures. After dehydration, the blocks were embedded in a modified mixture of glycol methacrylate (GMA), Quetol 523, methyl methacrylate (MMA) and QCU-1. Semi-thin sections, 0.2-0.3 micron thick, were stained by the PAS reaction, followed by counterstaining with hematoxylin if necessary. It was found that PAS reaction products representing the specific sites for glycosaminoglycans and glycoproteins were seen in both light and electron microscopy. In the control experiments the specificity of the reaction was confirmed. The granules of goblet cells were well stained and contrasted by the reaction materials. The basement membrane and the microvilli of the epithelial cells appeared as the staining layer. In the spermatocytes the reaction products were demonstrated in the Golgi apparatus, acrosomal vesicles and head cap. The results indicated that the PAS deposits became electron dense when the embedding matrix had a low electron scattering property. Using this method of preparing semi-thin sections, a comparative study of the localization of glycosaminoglycans was performed.

Animals↗
PubMed1984

Changes in thermal phase transition of various membranes during temperature acclimation in Tetrahymena.

Changes in the thermal phase transition temperature of membrane lipids were studied by X-ray wide-angle diffraction during adaptation of Tetrahymena pyriformis to a lower growth temperature. After a shift in growth temperature from 39 to 15 degrees C, the phase transition temperature was lowered gradually in microsomal and pellicular phospholipids, whereas that in mitochondrial phospholipids was unchanged for 10 h after the temperature shift. Only a small decrease in the transition temperature of mitochondrial phospholipids was observed, even after 24 h following the shift. Transition temperatures of microsomal, pellicular and mitochondrial phospholipids reached the growth temperature (15 degrees C) about 6, 10 and 24 h after the temperature shift. The temperature dependence of the solid phase in membrane phospholipids was estimated from the 4.2 A peak of the X-ray diffraction pattern. In the case of the phospholipids extracted from cells grown at 39 degrees C, the solid phase was increased upon lowering temperature in a similar manner in all three membrane fractions: mitochondria, pellicles and microsomes. However, in the case of the phospholipids from cells exposed to a lower growth temperature (15 degrees C) for 10 h, the increase in the solid phase was significantly smaller in mitochondrial phospholipids than in two other membrane fractions. The difference in the thermal behaviour of mitochondrial lipid from pellicular and microsomal lipids is discussed in terms of phase transition and phase separation.

Adaptation, Physiological↗
PubMed1984

Evaluation of left ventricular posterior wall movement after open mitral commissurotomy by echocardiogram: with reference to the effect of papilloplasty.

Left ventricular posterior wall movement in 20 patients with mitral stenosis (MS) was measured using M-mode echocardiogram in order to evaluate the improvement of myocardial function after open mitral commissurotomy (OMC) and compared between the cases with (10 patients) and without (10 patients) papilloplasty. The maximum left ventricular end-diastolic posterior wall velocity (LVPEVdmax) was increased from 71 +/- 12 to 90 +/- 16 mm/s in OMC patients (p less than 0.01) and from 59 +/- 19 to 101 +/- 28 mm/s in OMC + P patients (p less than 0.001). The maximum left ventricular systolic posterior wall velocity (LVPWVsmax) showed an increase from 51 +/- 9 to 62 +/- 10 mm/s in OMC patients (p less than 0.02) and from 48 +/- 10 to 69 +/- 8 mm/s in the OMC + P group (p less than 0.001). The mean LVPWVs increased from 35 +/- 8 to 48 +/- 8 mm/s in the OMC + P group (p less than 0.01). These parameters correlate fairly well with stroke volume index (SVI), ejection fraction (EF), and fractional shortening (FS) derived from internal LV dimensions. Thus, the posterior wall movement may prove to be useful as an index for evaluating the improvement of LV function after OMC.

Adult↗
PubMed1984

Configurations of myosin heads in the crab striated muscle as studied by X-ray diffraction.

The configurations of myosin projections in striated muscles from the marine crab, Portunus trituberculatus were described in the relaxed and rigor states at the full overlap length of the thin and thick filaments. The crystallographic period of the thick filament is 101.5 nm (14.5 nm X 7) and the thick filament has four-fold rotational symmetry. In the relaxed state, the myosin projections sit about 19 nm from the thick filament axis, lying just between the surface of the thick filament backbone and that of the thin filament. They have an elongated structure with the length of 10 nm approximately 12 nm and a maximum axial thickness of about 4 nm. They are tilted axially by 20 degrees approximately 30 degrees to the thick filament axis. The configuration of the resting projections sensitively depends on the ionic strength and pH of the solution. In the rigor state, myosin heads are bound periodically to the thin filaments ( Namba , Wakabayashi & Mitsui , 1980); four myosin heads attach in groups every 38.3 nm to successive actin molecules of each strand of F-actin. Most of the bound myosin head is incorporated in the thin filament with the centre of gravity 2.8 nm from the thin filament axis. They are inclined at about 30 degrees to and slewed round the thin filament axis.

Animals↗
PubMed1984

X-ray diffraction studies on photosystem I fragments from a blue-green alga, Anabaena variabilis, and spinach.

Photosystem I fragments were prepared from thylakoid membranes of a blue-green alga (Anabaena variabilis) and spinach by treatment with a detergent, Triton X-100. Equatorial X-ray diffraction patterns were recorded on films for oriented specimens of thylakoid membranes and photosystem I fragments. The thylakoid membranes and photosystem I fragments gave essentially the same equatorial diffraction patterns in both Anabaena variabilis and spinach, indicating that the major X-ray scatterers in these thylakoid membranes are the molecular assembly of photosystem I. The equatorial X-ray diffraction from the photosystem I fragments of Anabaena variabilis and spinach extends to the reciprocal space of 1/7 A-1. The diffraction pattern exhibits six to nine distinct maxima though they are diffuse, indicating that the arrangement of the constituent molecules in photosystem I has a definite geometrical regularity. The radial autocorrelation functions indicate that the maximal sizes of photosystem I in these thylakoid membranes are about 100 A, and the geometrical regularity does not correspond to a crystalline order. The X-ray diffraction patterns from photosystem I fragments from Anabaena variabilis and spinach are quite similar to each other, suggesting the possibility that the molecular structures of photosystem I in Anabaena variabilis and spinach have a fundamental similarity. These diffraction patterns, however, are different from that of the chromatophore obtained from a photosynthetic bacterium, Rhodospirillum rubrum.

Cyanobacteria↗
PubMed1984

Possible roles of calcium and calmodulin in the biosynthesis and secretion of alpha-amylase in rice seed scutellar epithelium.

The scutellar epithelial cells of rice (Oryza sativa L. cv Kimmazé) seeds actively secrete alpha-amylase in an early stage of germination. Employing an in vivo system of freshly dissected scutellar tissues, effect of Ca(2+) on the biosynthesis and the secretion of alpha-amylase have been studied. The maximum biosynthetic rate was saturated at about 0.5 mm external Ca(2+) concentrations, whereas the secretion continued to increase to concentrations above 10 mm Ca(2+). In the presence of 1 mm Ca(2+), 0.01 mum A-23187 significantly increased both the biosynthesis and the secretion of alpha-amylase.A cation-specific requirement for Ca(2+) was apparent, since both biosynthesis and extracellular secretion of alpha-amylase were inhibited by 0.1 mm EGTA but were increased above basal rate only with Ca(2+) and Sr(2+); K(+), Mg(2+), and Ba(2+) being ineffective.La(3+) and ruthenium red (selective inhibitors of [Ca(2+) + Mg(2+)]-ATPase) were found to profoundly inhibit the secretion of alpha-amylase. A calmodulin antagonist, W-7, also inhibited the secretion of alpha-amylase at concentrations where the enzyme synthesis was not much affected. Overall data indicate that Ca(2+) movement and secretion of alpha-amylase are tightly linked and it is likely that they are regulated by the cytoplasmic Ca(2+) concentration under possible control by calmodulin.

Journal Article↗
PubMed1984

D&C nos. 10 and 11: chemical composition analysis and delayed contact hypersensitivity testing in the guinea pig.

D&C Yellow no. 11 was found to consist predominantly of quinophthalone together with other minor components, though not 6'-methylquinophthalone. Quinophthalone was found to be a strong sensitizer in guinea pigs by means of a modified testing technique, and its threshold concentration for induction and challenge was 10 ppm. Purified D&C Yellow no. 10, which was found to consist of 6 derivatives of sodium sulfonated quinophthalone, did not sensitize or elicit a cross-reaction in quinophthalone-sensitized guinea pigs even at a challenge concentration of 5%. Commercial D&C Yellow no. 10 contained 0.95-170 ppm of quinophthalone, and it is suggested that skin sensitization by D&C Yellow no. 10 is caused by contaminating quinophthalone.

Animals↗
PubMed1984

Ultrastructural observations of chorionic villi at term in diabetic women.

An electron microscopic study has been performed on placentas from women with maternal diabetes. None of the patients had suffered from any of the hypertensive complications of pregnancy (White's class A). Most villous trophoblasts were morphologically normal and showed features suggestive of normal or increased synthetic transport and excretory activity. These cells appeared to be far more "active" than their counterparts in normal term placentas in that many contained Golgi bodies that were often associated with membrane-bound osmiophilic vesicles. Focal thickening of the trophoblastic basement membrane was seen. The endothelial capillaries contained an excessive number of microfibrillae and micropinocytotic vesicles and appeared unduly immature. Very abundant osmiophilic granules were seen in many villous components, such as syncytiotrophoblasts, stromal fetal endothelial cells, pericytes, Hofbauer cells and fibroblasts. These may have been concerned in the cross-transportation of materials between the maternal intervillous space and the fetal capillaries, rather than the incorporation of substances within them. These morphological changes did not show, however, any specific, constant or uniform pattern of abnormality attributable maternal diabetes.

Basement Membrane↗