Biomedical subjects

A Ohtsuka

Publications and source records attributed to A Ohtsuka.

At least 73 records · Page 4Linked to original sources

PubMed1998

Effects of thyroid hormones on myofibrillar proteolysis and activities of calpain, proteasome, and cathepsin in primary cultured chick muscle cells.

The effects of thyroxine (T4) and triiodothyronine (T3) on growth, muscle protein degradation, and proteases activities in cultured chick muscle cells were studied. The cells were treated with a physiological level of T4 (60 ng/mL) or T3 (12 ng/mL) for 6 d. Calpain, cathepsins, and proteasome activities and N tau-methylhistidine release were measured as indexes of myofibrillar protein breakdown. Creatine kinase activity was also measured as an index of myotube formation. Calpain activity was increased by T4 and T3. Cathepsin D and proteasome activities and N tau-methylhistidine release were increased by T3, but not by T4. Neither were cathepsin B and B + L activities affected by T3 or T4. Creatine kinase activity was increased by T4 and T3. The results suggest that myotube formation is accelerated by T4 and T3, whereas myofibrillar protein degradation is accelerated by T3, but not by T4.

Animals↗

PubMed1997

Localization of membrane-associated sialomucin on the free surface of mesothelial cells of the pleura, pericardium, and peritoneum.

Strong anionic sites, as recognized by deposition of cationic colloidal iron even at pH 1.5, were distributed on the free surfaces of the mesothelia of the mouse pleura, pericardium, and peritoneum. Methylation inhibited colloidal iron staining on the surface, and successive saponification restored it. Digestion with neuraminidase or hydrolysis of sialic acid with H2SO4 erased the colloidal iron staining. Lectin Limax flavus agglutinin (LFA), which is specific for sialic acid, labeled the free surface of the mesothelium. All these findings strongly suggested that the surface substance contained sialic acid. Moreover, prior treatment with LFA inhibited the mesothelial surface stain with colloidal iron. In transmission electron microscopy, the colloidal iron (pH 7.3)-stained substance took the shape of fine strands of 50-300 nm in length. These characteristics of the substance on the mesothelial surface correspond well with biochemical properties of membrane-associated sialomucin, whose strong and abundant negative charges produce repulsive forces between facing serosal surfaces. This may contribute to prevent serosal adhesion and to reduce friction during movements of organs.

Animals↗

PubMed1997

Effect of environmental temperature on muscle protein turnover and heat production in tube-fed broiler chickens.

The present experiments were undertaken to investigate the effects of environmental temperatures on growth, abdominal fat content, rate of muscle protein turnover, and heat production in tube-fed intact male broiler chickens. Plasma concentrations of thyroxine (T4), triiodothyronine (T3), and corticosterone (CTC) were also examined. Chicks (15 d old) were kept at different environmental temperatures (16, 19, 22, 25, 28, 31, and 34 degrees) and given the experimental diet (200 g crude protein/ kg, 13.57 MJ/kg metabolizable energy) by tube three times daily throughout the 12 d experimental period. In the hot conditions, except for 34 degrees, body-weight gain was significantly higher than in the cold conditions. Thus, food conversion ratios (food:gain ratios) were lower when the birds were exposed to the hot conditions other than 34 degrees. Likewise, abdominal fat content was significantly increased, and heat production was lower in the groups kept under the hot conditions other than 34 degrees. The rate of skeletal muscle protein turnover and plasma concentration of CTC were decreased when the birds were exposed to hot conditions other than 34 degrees, suggesting a role of CTC in the regulation of muscle protein turnover. Plasma concentrations of T4 and T3 were significantly decreased as environmental temperature increased. These results clearly show that plasma concentrations of thyroid hormones and CTC are associated with accelerated muscle protein turnover and heat production.

Adipose Tissue↗

PubMed1997

Growth factors for a primary chick muscle cell culture from shochu distillery by-products.

An unidentified growth factor (UGF) was separated from shochu distillery by-products (SDBP) and its effect on the growth of a primary chick muscle cell culture was investigated. Chick muscle cells were isolated from fertile eggs (13-day-old embryos) of commercial broilers. UGF was separated on Sephadex LH-20 with a solvent system of water-methanol-ethylene dichloride (10:90:20, v/v), and the fraction eluted between 136 and 164 min was collected (fraction I). Fraction I was further purified by HPLC with an Inertsil ODS-2 column using a solvent system of methanol-butanol (80:20, v/v). Three fractions having retention times of 3.76, 4.57, and 5.12 min were collected and are referred to as fraction A, B, and C, respectively. In experiment 1, chick muscle cells were cultured in an m-199 medium containing 0.001, 0.01, or 0.1% of fraction I. In experiment 2, chick muscle cells were cultured with 0.01 or 0.005% of each fraction A, B, and C. Creatine kinase (CK) activity, protein and DNA contents were measured as indices of myotube growth, cell growth and cell proliferation, respectively. N tau-methylhistidine (N tau-MH) release from the muscle cell was also measured to observe the effect on proteolysis. In experiment 1, the protein content was significantly (p < 0.05) increased by fraction I, despite the low dose level. CK activity was significantly (p < 0.05) higher than the control when 0.001% of fraction I was added to the medium. However, increasing the level beyond 0.01% did not further increase the CK activity. The DNA content was not significantly changed. In experiment 2, the protein content, CK activity, and DNA content were significantly (p < 0.05) higher when fractions A and B were added to the medium. However, this was not the case when fraction C was added. N tau-MH release was significantly (p < 0.05) higher when fraction A was added, but, was significantly (p < 0.05) lower when fraction B was added, while fraction C had no effect on N tau-MH release. The present results show that SDBP contained two growth-promoting factors for a primary chick muscle cell culture, although their modes of action may be different.

Animals↗

PubMed1997

Dark and light neurons in the human brain, with special reference to their reactions to Golgi's silver nitrate, luxol fast blue MBS and azocarmine G.

Sections from the human somatosensory cortex were observed with a light microscope. The neurons were classified into light and dark ones. The light neurons were slightly stained with thionin, luxol fast blue MBS and azocarmine G (80% of all neurons). The dark neurons were more or less shrunken, and stained intensely with these dyes (20% of all neurons). Double staining with luxol fast blue MBS and azocarmine G was especially useful to demonstrate the dark neurons, since it clearly stained even their fine processes. Neither light nor dark neurons were reactive to nick end labeling for detection of DNA fragmentation. Triple staining with Golgi's silver nitrate (or Gallyas's ammoniacal silver carbonate), luxol fast blue MBS and azocarmine G show that the majority of the dark neurons were argyrophilic (argyrophilic dark neurons, 15% of all neurons), while some of them were not argyrophilic (non-argyrophilic dark neurons, 5% of all neurons). Triple staining also showed that the light neurons were only occasionally argyrophilic (argyrophilic light neurons, 5% of all neurons); usually, the light neurons were not argyrophilic (non-argyrophilic light neurons, 75% of all neurons). The results confirm that dark neurons usually represent certain populations of neurons in the human brain, and that they are basically identical to the argyrophilic neurons. The discussion suggests that the argyrophilic light and dark neurons are excited cells, the non-argyrophilic dark neurons are exhausted cells, and the non-argyrophilic light neurons are resting cells. Triple staining further demonstrated that some glial cells were darkened and stained with Golgi's silver nitrate or Gallyas's silver carbonate. Additional Golgi's silver block staining showed that the argyrophilic neurons stained by the conventional block staining method usually possessed a shrunken cell body, which was characteristic of the dark neurons.

Aged↗

PubMed1997

Perineuronal sulfated proteoglycans and cell surface glycoproteins in adult and newborn mouse brains, with special reference to their postnatal developments.

Sections of the retrosplenial cortex from adult and newborn mouse brains were observed with a light microscope. The retrosplenial cortex of the adult animals contained many neurons (10% of the total), including some dark neurons, with perineuronal sulfated proteoglycans detectable with cationic iron colloid and aldehyde fuchsin. The retrosplenial cortex of the adult animals also contained many neurons (10% of the total) with cell surface glycoproteins reactive to lectin Vicia villosa, soybean or Wisteria floribunda agglutinin. Double staining showed that the majority (75%) of the neurons labeled with lectins were stained with cationic iron colloid, and that some (25%) of them were not stained with this colloid. Double staining also showed that some (25%) of the neurons stained with cationic iron colloid were not labeled with lectins. These findings indicate that the perineuronal sulfated proteoglycans are, at least partly, independent from the cell surface glycoproteins. Observations of the sections from the newborn animals revealed that the perineuronal sulfated proteoglycans were produced by the associated satellite astrocytes 3-4 weeks after birth, and that the cell surface glycoproteins were produced by the associated nerve cells at earlier stages, or 2-3 weeks after birth. Dark neurons began to appear 3-4 weeks after birth. These dark neurons or their Golgi complexes were also reactive to lectins, suggesting the production of cell surface glycoproteins.

Aging↗

PubMed1997

Negative charges bound to collagen fibrils in the rabbit articular cartilage: a light and electron microscopic study using cationic colloidal iron.

Negative charged sites in the normal rabbit articular cartilage were investigated using cationic colloidal iron methods. In light microscopy of the cartilage stained with the colloidal iron at pH 1.5, a distinct Prussian blue reaction was observed in the pericellular matrix, and a weak blue reaction in the territorial and interterritorial matrices. At pH 7.0, a diffuse Prussian blue reaction was observed in the pericellular and interterritorial matrices. Digestion with chondroitinase ABC, hyaluronidase and keratanase could not erase the Prussian blue reaction. However, the sections digested with collagenase followed by chondroitinase ABC showed significant elimination of the Prussian blue reaction. Electron microscopy of ultrathin sections stained with the colloidal iron at pH 1.5 revealed that the cationic colloid particles were deposited abundantly in the pericellular matrix and dotted along collagen fibrils in the territorial and interterritorial matrices. The present results suggest that negatively charged sites in the articular cartilage derive mostly from chondroitin sulfate, whose proteoglycans firmly bind to collagen fibrils. Such an ultrastructure may maintain the electrostatic microenvironment in the collagen plexus, holding much water in the cartilage matrix, and also producing biomechanical properties such as tensile strength and elasticity of the cartilage.

Animals↗

PubMed1997

Perineuronal sulfated proteoglycans and cell surface glycoproteins in the visual cortex of adult and newborn cats.

Sections of the visual cortex of newborn (1-4 weeks after birth) and adult cats were stained with cationic iron colloid, aldehyde fuchsin or lectins (lectin Vicia villosa, soybean and Wisteria floribunda agglutinins). Many neurons in the adult cat visual cortex contained perineuronal sulfated proteoglycans detectable with cationic iron colloid and aldehyde fuchsin, or cell surface glycoproteins reactive to lectins. Double staining indicated that some of the lectin-labeled neurons were not stained with cationic iron colloid, and also that some of the cationic iron colloid-stained neurons were not labeled with lectins. The perineuronal sulfated proteoglycans and cell surface glycoproteins developed 3 weeks after birth. In the newborn cats 1-2 weeks after birth, no neurons were reactive to cationic iron colloid, aldehyde fuchsin or lectins. In the newborn cats 3-4 weeks after birth, it was clearly observed that the cytoplasm of the glial cells closely associated with the neurons containing the perineuronal sulfated proteoglycans showed an intense reaction to cationic iron colloid and aldehyde fuchsin, and that the Golgi complexes of the neurons with cell surface glycoproteins were intensely labeled with lectins. These findings suggest that the perineuronal sulfated proteoglycans are derived from the associated glial cells, and that the cell surface glycoproteins are produced by the associated nerve cells.

Animals↗

PubMed1996

NMR studies on water and polymer diffusion in dextran gels. Influence of potassium ions on microstructure formation and gelation mechanism.

At room temperature aqueous solutions of dextrans with concentrations > 25% (w/w) exhibit a sol-gel transition in the presence of > 1.0 M potassium chloride. In dextrans the gelation was unexpected due to missing anionic groups that usually provide the binding sites for cations. The quantitative investigation of the gel formation is based on changes of the diffusibility of water and dextran chains. The apparent diffusion coefficients of bulk water (in the order of 10(-6) cm2/s) and of water trapped in the junction zones as well as of polymer chains (in the order of 10(-7) to 10(-8) cm2/s) are determined by employing pulsed field gradient stimulated echo (PFGSTE) NMR. The restricted diffusion of bulk water in viscous sols and in soft and rigid gels has been quantitatively analyzed providing data for interbarrier distances (pore size), permeabilities of the diffusion barriers (density of junction zones) and interbarrier diffusion coefficients of water. Based on already published x-ray structure data and in accordance with the diffusion data presented in this paper "potassium-bonding" is assumed to be the most important interaction for the formation of a microstructure and for the stabilization of cross-links. The ionic radius of the potassium ion perfectly fits to the cage established by six oxygen atoms of glucose units of three polymer chains. Other cations, such as Li+, Na+, Rb+ and Cs+, according to their nonfitting ionic radii, do not provoke dextran gelation under these conditions. The mechanism of the transitions from sol to soft gel and further to rigid gel is discussed on the basis of restricted diffusion and x-ray structure data.

Dextrans↗

PubMed1996

Neurons with perineuronal sulfated proteoglycans in the mouse brain and spinal cord: their distribution and reactions to lectin Vicia villosa agglutinin and Golgi's silver nitrate.

This study demonstrates that many neurons in the somatosensory cortex, cingulate cortex, retrosplenial cortex and hippocampal subiculum of the mouse brain are covered by sulfated proteoglycans which are intensely negative-charged and stained with cationic iron colloid, while being digested with hyaluronidase. Neurons with similar perineuronal proteoglycans are also recognized in the extrapyramidal system (superior colliculus, red nucleus, reticular formation, vestibular nuclei and cerebellar nuclei), in the secondary auditory system (cochlear nuclei, nucleus of trapezoid body, inferior colliculus and nucleus of lateral lemniscus), in the vestibulo-ocular reflex system (vestibular nuclei and extraocular motor nuclei), and in the pupillary reflex system. The neurons with perineuronal sulfated proteoglycans in the cerebral cortices and hippocampal subiculum are usually labeled with the lectin Vicia villosa agglutinin, though those in the cerebellar, vestibular and cochlear nuclei may not be reactive to this lectin. Double staining of the retrosplenial cortex, hippocampal subiculum and cerebellar nuclei with Golgi's silver nitrate and cationic iron colloid indicates that the perineuronal sulfated proteoglycans are identical with the Golgi's reticular coating or glial nets.

Animals↗

PubMed1996

Perineuronal sulfated proteoglycans in the human brain are identical to Golgi's reticular coating.

Many neurons in the human somatosensory cortex (Area 7 of Brodmann) possess an intensely negative-charged surface coat consisting of perineuronal sulfated proteoglycans which were stained with cationic iron colloid. This surface coat was stained doubly with cationic iron colloid and Golgi's silver nitrate. The result indicates that the perineuronal sulfated proteoglycans are identical with Golgi's reticular coating, whose existence and nature have previously been controversial. The result also suggests that Golgi's silver nitrate stains the core proteins of proteoglycans.

Aged↗

PubMed1996

Dark neurons in the mouse brain: an investigation into the possible significance of their variable appearance within a day and their relation to negatively charged cell coats.

This study aims to investigate the occurrence and nature of dark neurons in the central nervous system under physiological conditions. Mouse brain tissues were perfusion-fixed with paraformaldehyde or glutaraldehyde at 4 h intervals during one day (3:00, 7:00, 11:00, 15:00, 19:00, 23:00). Paraffin sections were stained with the cationic colloidal iron method, and counterstained with nuclear fast red or carbolthionin. The dark neurons were readily distinguishable as their shrunken cell bodies stained densely with nuclear fast red or thionin. Some of the dark cells were coated with perineuronal sulfated proteoglycans; this coat, which formed a smoothly extended meshwork in light cells, presented spicule-like forms in the dark cells. The occurrence of dark cells in the retrosplenial cortex varied by the time of day: the incidence of the dark neurons was low (10-15%) at 11:00, 15:00 and 23:00, while it was significantly high (50-60%) at 3:00 and 19:00. Previous authors have ascribed the occurrence of dark neurons either to artifacts due to inappropriate fixation or to pathological damage. However, the present study strongly suggests that this type of neuron occurs under physiological conditions as reversible changes, and vary over a day, showing distinct peaks. These peaks occurred coincidentally while the mice were awake. Such morphological changes may be involved in the neuronal activation and exhaustion. Our view is consistent with the hypothesis (Tewari and Bourne, 1963) that the neurons take such dark profiles at certain stages of neurosecretion.

Animals↗

PubMed1996

Perineuronal sulfated proteoglycans, cell surface glycoproteins and dark neurons in the cingulate cortex of newborn and adult rats.

Many neurons in the adult rat cingulate cortex possess perineuronal sulfated proteoglycans detectable with cationic iron colloid and aldehyde fuchsin, or cell surface glycoproteins reactive to lectin Vicia villosa or soybean agglutinin. The perineuronal sulfated proteoglycans develop three to four weeks after birth. The cell surface glycoproteins develop at earlier stage or two to three weeks after birth. Dark or active neurons begin to appear three to four weeks after birth. These findings indicate that the brain matures after birth or during weaning period.

Animals↗

PubMed1996

Perineuronal sulfated proteoglycans in the adult rat brain: histochemical and electron microscopic studies.

Neurons of cerebellar nuclei in the rat brain had a marked surface coat which was stained with cationic iron colloid or aldehyde fuchsin. Neurons with a similar surface coat were also noted in the retrosplenial cortex. The surface coat was stained doubly with cationic iron colloid and aldehyde fuchsin. Digestion with hyaluronidase eliminated the stainability of the surface coat to both agents. Combined digestion with chondroitinase ABC, heparitinase and keratanase eliminated the cationic iron colloid staining but did not interfere with the aldehyde fuchsin staining. Electron microscopy of ultrathin sections revealed that the iron particles were deposited in the perineuronal tissue spaces. These findings indicate that the surface coat consists of sulfated proteoglycans which occupy, as the extracellular matrix, the perineuronal tissue spaces. Many neurons in the retrosplenial cortex were labeled with lectin Vicia villosa agglutinin. Double staining revealed that these lectin-labeled neurons are usually reactive to cationic iron colloid. Few neurons in the cerebellar nuclei were labeled with lectin V. villosa agglutinin.

Animals↗

PubMed1996

Rat parathyroid gland, with special reference to its blood vascular bed, pericapillary space and intercellular space.

The blood vascular bed, perivascular space and intercellular space of the rat parathyroid gland were studied using scanning electron microscopy of vascular casts, freeze-cracked tissue samples, and NaOH-digested tissue blocks. The findings were supplemented by transmission light and electron microscopy of iron colloid-treated or enzyme-digested tissue sections. The rat parathyroid gland contained a rich network of capillaries. These capillaries were surrounded by marked pericapillary spaces which were demarcated by basal lamina of both capillaries and parenchymal cells. The pericapillary spaces contained numerous collagen fibrils, and issued many crista-like projections which ran deep into the sheets of parenchymal cells. The intercellular spaces of parenchymal cells contained neither basal lamina nor collagen fibrils. The surfaces of the parenchymal cells showed strong negative charging, and maintained the intercellular spaces. The luminal surfaces of the capillary endothelium also showed strong negative charging, and maintained the capillary lumen.

Animals↗

PubMed1996

Calcitonin decreases corticosterone-induced skeletal muscle calpain activity.

The effects of calcitonin (CT) administration on calcium (Ca) concentrations in plasma and skeletal muscle as well as the calpain activity of skeletal muscle were examined in young growing male rats treated with corticosterone (CTC). The rats received subcutaneous injections of CTC (5 mg/100 g body weight/day), or both CTC and CT (100 m unit/100 g body weight/day) for four days. Control rats received placebos. The rats were sacrificed 24 h after the final injections, and blood was taken followed by dissections to remove gastrocnemius and extensor digitorum longus muscles. Plasma Ca concentration was increased and muscle Ca concentration and its calpain activity tended to be increased by CTC. The CTC-induced increases in muscle Ca concentration and its calpain activity were significantly minimized by the simultaneous injection of CT. However, CTC-induced hypercalcemia was not minimized by CT. The present observations indicate that CT decreases Ca concentration in skeletal muscle cell and its calpain activity, followed by a suppression of muscle proteolysis in rats treated with CTC.

Animals↗

PubMed1996

Bicuspid aortic valve in an adult human cadaver: a case report.

We encountered a "bicuspid" aortic valve in an 83-year-old man. This valve consisted of two semilunar leaflets, anterior and posterior, though they were extensively calcified. The right and left coronary arteries independently arose from the anterior aortic sinus. The infundibular ligament ran from the pulmonary trunk at the commissure of the right and left semilunar cusps to the aorta at the mid-point of the anterior sinus. These findings strongly suggests the present bicuspid aortic valve may be formed by fusion of usual right and left (coronary) cusps. No other congenital anomalies were noted in this heart.

Aged↗

PubMed1995

A novel serpin-like protein, B-43, exists in both neurons and astrocytes: an immunohistochemical study in the parietal region of the bovine brain.

The presence of a novel member of serine proteinase inhibitor, B-43, was immunohistochemically indicated in both neurons and astrocytes in the parietal region of the bovine brain. B-43-like immunoreactivity was detected in pyramidal cells in the cortex and GFAP-positive astroglial cells in the white matter. The processes of B-43 may play a cooperative role with glia-derived nexin/protease nexin-1 and alpha 1-antichymotrypsin in the brain.

Animals↗