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Biomedical subjects

A Ohtsuka

Publications and source records attributed to A Ohtsuka.

At least 37 records · Page 2Linked to original sources
PubMed2001

A high dose of vitamin E inhibits adrenal corticosterone synthesis in chickens treated with ACTH.

The present experiment was conducted to study the effects of dietary vitamin E on plasma corticosterone (CTC) concentration and adrenal steroid syntheses in chickens treated with adrenocorticotropic hormone (ACTH). Chickens were divided into ACTH(-) and ACTH(+) groups, and each group was further divided into three subgroups administered with vitamin E (500 or 5,000 mg/kg diet) and without the vitamin. Vitamin E (DL-alpha-tocopheryl acetate) was mixed with the basal diet at levels of 500 and 5,000 mg/kg and fed for 6 d. ACTH (20 IU/kg body weight) was given daily by intraperitoneal injection for 5 d. alpha-Tocopherol levels in the plasma and adrenal gland were markedly elevated by vitamin E feeding, and the level of adrenal free cholesterol (CHOL), which is used for steroid synthesis, was significantly decreased by vitamin E feeding in a dose-dependent manner. However, the level of adrenal CHOL ester was unchanged by any treatment. The elevations of pregnenolone, progesterone and CTC levels in the adrenal gland of chickens with ACTH treatment were decreased by vitamin E administration. The elevation of plasma CTC concentration in the ACTH(+) group was dramatically decreased by vitamin E administration, while that concentration was not influenced by the vitamin administration in the ACTH(-) group. These findings indicate that vitamin E suppresses the elevation of the plasma CTC concentration due to ACTH in chickens, possibly by inhibiting the conversion of CHOL ester to free CHOL in the adrenal gland.

Adrenal Glands↗
PubMed2001

Repulsive charge mechanism serve to maintain lumens and cavities. An histochemical study of rat serosa and kidney.

The free surface of the rat peritoneum was covered with a rich negative-charged substance which is distinctly stained with cationic colloidal iron (pH 1.5). Neuraminidase digestion erased this iron stain. Treatment with Limax flavus agglutinin (LFA), which has specific affinity to sialic acid, interferred with iron staining on the serosal surface. Transmission electron microscopy of the peritoneal samples stained with colloidal iron showed that colloidal particles were deposited on the free surface of the mesothelial cells. At pH 1.5, the colloidal particles aggregated in a dotted fashion; in those stained at pH 7.0, the particles arranged in fine strands (100-300 nm in length). This difference may occur as a structural transformation due to pH level changes. The string like structure seemed to correspond well to membrane associated sialomucin. The urinary surface of the rat glomerular podocytes possessed negatively charged sites detectable with cationic colloidal iron even at pH 1.5. Neuraminidase and LFA treatments erased iron staining. Substance containing sialic acid such as podocalyxin on the podocyte surface may be stained. This study shows that negatively charged sites of the substance covering the free surface of these regions repulse each other to maintain the serosal cavities or the podocyte end-feet slits.

Animals↗
PubMed2001

The extracellular matrix in the mature brain: its reactions to endo-alpha-N-acetylgalactosaminidase and collagenase.

The hippocampal subiculum in the adult rat brain contains many neurons with nerve cell surface glycoproteins which are linked by collagenous ligands to perineuronal proteoglycans. The nerve cell surface glycoproteins or their terminal N-acetylgalactosamines are digested by endo-alpha-N-acetylgalactosaminidase. The terminal N-acetylgalactosamines linked by the collagenous ligands are not digested by endo-alpha-N-acetylgalactosasminidase. The collagenous ligands associated with the terminal N-acetylgalactosamines were digested by collagenase. The newly exposed terminal N-acetylgalactosamines by this collagenase incubation were digested by endo-alpha-N-acetyl-galactosaminidase. These findings on the rat agree with those obtained in our previous studies of the adult mouse brain samples. Furthermore they emphasize our hypothetical model that the perineuronal proteoglycans are related--via collagen ligands--with the nerve cell surface glycoproteins.

Animals↗
PubMed2000

Is the morphology of the articular eminence of the temporomandibular joint a predisposing factor for disc displacement?

OBJECTIVES: To test the hypothesis that the morphology of the articular eminence of the TMJ is a predisposing factor for disc displacement. METHODS: MR images of 220 TM joints in 151 patients were studied: 47 joints had no disk displacement (NDD), 81 joints disc displacement with reduction (DDWR) and 92 joints disc displacement without reduction (DDWOR). The shape of the articular eminence of the TMJ was classified into four types, box, sigmoid, flattened and deformed. The prevalence of the box and flattened forms in the three groups of joints was compared. RESULTS: There was no statistically significant difference in the prevalence of the box form between the joints with NDD, DDWR, and DDWOR. On the other hand, the prevalence of the flattened-type was statistically lower in the joints with DDWR (goodness test of fit for chi 2, P < 0.05). CONCLUSIONS: It appears that disc displacement is less likely to be found in joints with a shallow articular eminence.

Analysis of Variance↗
PubMed2000

Flattening of the articular eminence correlates with progressive internal derangement of the temporomandibular joint.

OBJECTIVES: To test the hypothesis that flattening of the slope of the articular eminence occurs with progressive internal derangement (ID) of the TMJ. METHODS: MR images of 170 TMJs in 130 patients with proven disk displacement were studied. The correlation between the prevalence of a flattened articular eminence and radiological stage of ID was analysed. RESULTS: The prevalence of a flattened articular eminence was significantly higher in the joints with advanced ID (Mann-Whitney's U-test, P < 0.05). CONCLUSIONS: It appears that a flattening of the slope of the articular eminence occurs as a result of remodeling or degenerative changes secondary to ID.

Adolescent↗
PubMed2000

The relationship between the degree of disk displacement and ability to perform disk reduction.

OBJECTIVE: To evaluate the difference in temporomandibular joint (TMJ) disk position between reducible and permanently displaced disks. STUDY DESIGN: We found 182 joints with disk displacement (83 with reduction and 99 without reduction) that were available for the study. The disk position was estimated by using magnetic resonance imaging. RESULTS: There was a statistically significant difference between them with the permanently displaced disks being located more anteriorly. When a comparison was made in the disks as to which degree of displacement was moderate, a difference of disk position at either the medial or lateral depth of the TMJ was observed. CONCLUSION: It was suggested that the permanently displaced disks are located more anteriorly than the reducible displaced disks. When the disk displacement was moderate, disk reduction was influenced by less disk displacement at either the medial or lateral part of the TMJ.

Adolescent↗
PubMed2000

Immunohistochemical localization of histamine N-methyltransferase in guinea pig tissues.

Histamine plays important roles in gastric acid secretion, inflammation, and allergic response. Histamine N-methyltransferase (HMT; EC 2.1.1.8) is crucial to the inactivation of histamine in tissues. In this study we investigated the immunohistochemical localization of this enzyme in guinea pig tissues using a rabbit polyclonal antibody against bovine HMT. The specificity of the antibody for guinea pig HMT was confirmed by Western blotting and the lack of any staining using antiserum preabsorbed with purified HMT. There was strong HMT-like immunoreactivity (HMT-LI) in the epithelial cells in the gastrointestinal tract, especially in the gastric body, duodenum, and jejunum. The columnar epithelium in the gallbladder was also strongly positive. Almost all the myenteric plexus from the stomach to the colon was stained whereas the submucous plexus was not. Other strongly immunoreactive cells included the ciliated cells in the trachea and the transitional epithelium of the bladder. Intermediately immunoreactive cells included islets of Langerhans, epidermal cells of the skin, alveolar cells in the lung, urinary tubules in the kidney, and epithelium of semiferous tubules. HMT-LI was present in specific structures in the guinea pig tissues. The widespread distribution of HMT-LI suggests that histamine has several roles in different tissues.

Animals↗
PubMed2000

The spatial relationship between the perineuronal proteoglycan network and the synaptic boutons as visualized by double staining with cationic colloidal iron method and anti-calbindin-D-28K immunohistochemistry in rat cerebellar nuclei.

The present study demonstrated the precise spatial relationship between meshes in the perineuronal proteoglycan network and the terminal boutons of synaptically associated axons. Sections from the rat cerebellum were stained with cationic colloidal iron (pH 1.0-1.5), and successively immunostained with anti-calbindin-D-28K monoclonal antibody. Cationic iron stained sulfated proteoglycans around the nerve cell of the medial cerebellar nucleus, whereas the anti-calbindin antibody labeled the Purkinje cells including their axons terminating on large neurons in the cerebellar nucleus. It was found that each synaptic bouton fits into a mesh of the perineuronal network. The individual meshes appeared to be divided by partitions faintly stained with the colloidal iron. Electron microscopy of cationic colloidal iron-stained ultrathin sections revealed that the synaptic boutons were separated from each other by the proteoglycan matrix and that each of them was further divided into two or more contact areas of presynaptic membrane by the same matrix. This suggests that individual synapses are protected against the effects of adjacent synaptic transmission, and that each of them may be subdivided by this manner of partitioning, like pads of a cat's paw.

Animals↗
PubMed2000

Enhanced visualization of weak colloidal iron signals with Bodian's protein silver for demonstration of perineuronal nets of proteoglycans in the central nervous system.

The present study aimed for a clear visualization of faintly deposited colloidal iron in tissue sections for light microscopy. Paraffin blocks containing paraformaldehyde-fixed brain tissue from healthy adult mice were cut into sections 10-15 microm thick. After deparaffinization, the sections were stained with fine cationic iron colloid at a pH value of 1.0-1.5, and treated with a mixture of potassium ferrocyanide and hydrochloride for Prussian blue reaction. Some sections were further treated with Bodian's protein silver after the Prussian blue reaction. This sensitized development of Prussian blue reaction with Bodian's protein silver more clearly visualized the faintly deposited cationic colloidal irons than the demonstration by Prussian blue reaction alone, and allowed an enhanced visualization of the perineuronal nets of sulfated proteoglycans in the brain. Thus, such fine perineuronal sulfated proteoglycans as those in the CA3 field of the hippocampus, which are weakly stained with cationic iron colloid and usually overlooked by a demonstration with only a Prussian blue reaction, could be clearly visualized with striking contrast by the sensitized development with Bodian's protein silver after the Prussian blue reaction. Preliminary hyaluronidase digestion erased Bodian's protein silver development of perineuronal sulfated proteoglycans. Though some axonal fibers were also additionally stained with Bodian's protein silver itself, this sensitized development is useful to enhance such weak colloidal iron signals as are hardly detectable by only Prussian blue reaction.

Animals↗
PubMed2000

Intensely negative-charged pericapillary spaces in the rat pineal gland.

Electron microscopy of ultrathin sections stained with cationic iron colloid revealed that the rat pineal gland is provided with wide and intensely negative-charged pericapillary spaces. Light microscopically, the negative charging of the pericapillary spaces was completely eliminated by digestion with hyaluronidase and chondroitinase ABC. This pericapillary negative charging was also erased by digestion with collagenase. The results indicate that the negative charging is derived from sulfated proteoglycans which are bound to collagen molecules. These sulfated proteoglycans in the pericapillary spaces may retain numerous water molecules to form a tissue gel, and so act as a selective sieve regulating the passage of tissue molecules.

Animals↗
PubMed2000

Typology of the arteries in the human scalenus region, with special reference to the accessory ascending cervical artery.

The accessory ascending cervical artery (Murakami et al., 1996), which arises from the subclavian artery and ascends between the scalenus anterior and medius muscles, was studied in 87 Japanese adult cadavers (174 sides), with special attention being given to its origin, distribution, and relationship to other arteries at the cervical or scalenus region. In 154 sides (88.5%), the accessory ascending cervical artery was found to originate from the subclavian artery behind the scalenus anterior muscle, and to branch out to the scalenus anterior and medius muscles as well as those entering the 5th and 6th intervertebral foramens along the 6th and 7th cervical nerves. This artery arose independently in 105 sides. The accessory ascending cervical artery issued off or formed a common trunk with the transverse cervical artery and/or costocervical trunk in 49 sides. In cases lacking the accessory ascending cervical artery, it was usually compensated for by the costocervial trunk and/or transverse cervical artery (18 sides). Common trunk formation with the vertebral, internal thoracic, or suprascapular arteries was not observed. The authors suggest that the accessory ascending cervical artery, the transverse cervical artery, and the costocervical trunk should be grouped into one arterial system, a system that may be a remnant of the precostal longitudinal anastomoses of intersegmental arteries of the dorsal aorta behind the scalenus anterior muscle.

Aged↗
PubMed2000

The perineuronal proteoglycan surface coat in the adult rat brain, with special reference to its reactions to Gömöri's ammoniacal silver.

The present study showed that many neurons in the adult rat brain possessed a perineuronal sulfated proteoglycan surface coat which reacted to cationic iron colloid and aldehyde fuchsin. This surface coat was stained supravitally with Ehrlich's methylene blue and doubly stained with Ehrlich's methylene blue and aldehyde fuchsin. The surface coat was also stained with Gömöri's ammoniacal silver and doubly stained with Gömöri's ammoniacal silver and cationic iron colloid. The surface coat was usually expressed together with a nerve cell surface glycoprotein net detectable with lectin Wisteria floribunda agglutinin. These findings indicate that the perineuronal proteoglycan surface coat is identical to Cajal's superficial reticulum and contains some collagenous elements. It was further demonstrated that collagenase digestion erased Gömöri's ammoniacal silver impregnation within the perineuronal proteoglycan surface coat.

Animals↗
PubMed2000

[Non-randomized study on the effects of preoperative radiotherapy and daily administration of low-dose cisplatin against those of radiotherapy alone for oral cancer--effects on local control, control of metastases, and overall survival].

Cisplatin is a known radiation modifier. Our previous study suggested that daily administration of low-dose cisplatin enhanced the efficacy of radiotherapy against primary oral squamous carcinoma. In this paper, we follow the patients who participated in the previous study and survey the benefit of combination low-dose cisplatin in improving local control, prevention of metastases, and overall survival. This study included patients with surgically resectable advanced oral tumors. Ten patients underwent preoperative radiotherapy of 30-40 Gy/15-20 days with concomitant daily administration of low-dose cisplatin (5 mg/body or 5 mg/m2). Ten other patients received external radiotherapy alone. All patients then underwent a planned radical tumor resection. No significant difference was see in loco-regional control rates (primary: 86 vs. 88%, neck: 83 vs. 78% at 48 months) or incidence of metastasis (70 vs. 64%) between the two groups. Nor was there a significant difference in the overall survival rate (60 vs. 66%). The results of this study suggest that the concomitant use of daily administration of low-dose cisplatin with preoperative radiation brings no statistically significant benefit in improving local control and survival rate in patients with advanced resectable oral cancer.

Adult↗
PubMed2000

Selenium influences growth via thyroid hormone status in broiler chickens.

As there is a possibility that Se influences the growth of animals via thyroid hormone metabolism, the following three experiments were undertaken in order to determine the effects of dietary Se on growth, skeletal muscle protein turnover and thyroid hormone status in broiler chickens. Broiler chickens were raised on a Se-deficient diet until 12 d of age and then used for the experiments. In Experiment 1, twenty-eight birds were randomly assigned to four groups and fed purified diets with the following amounts of Se supplementation: 0.0, 0.1, 0.3 and 0.5 mg Se/kg diet. Dietary Se supplementation significantly increased plasma 3,5,3'-triiodothyronine (T3) concentration and improved growth, while plasma thyroxine (T4) concentration was decreased. In Experiment 2, twenty-eight birds were assigned to four groups and fed either a Se-deficient diet or a Se-supplemented diet (0.3 mg Se/kg diet) with or without the supplementation of iopanoic acid, a specific inhibitor of 5'-deiodinase (5 mg/kg diet). The growth was promoted and feed efficiency was improved by dietary Se supplementation as was also observed in Experiment 1. However, this effect of Se was halted by iopanoic acid supplementation. Hepatic 5'-deiodinase activity was elevated by Se and inhibited by iopanoic acid. In Experiment 3, birds were fed on the following diets to show that Se influences growth of birds via thyroid hormone metabolism: Se-deficient diet, Se-supplemented diets (0.1 and 0.3 mg/kg) and T3 supplemented diets (0.1 and 0.3 mg/kg diet). Lower dietary T3 supplementation (0.1 mg/kg diet) resulted in growth promotion similar to Se supplementation, while higher level of T3 caused growth depression. Furthermore, it was observed that the rate of skeletal muscle protein breakdown tended to be increased by Se similarly to the effect of T3. In conclusion, it was shown in the present study that Se deficiency depresses growth of broilers by inhibiting hepatic 5'-deiodinase activity which causes lower plasma T3 concentration.

Analysis of Variance↗
PubMed1999

Efficacy of a mandibular manipulation technique in reducing the permanently displaced temporomandibular joint disc.

PURPOSE: The purpose of this study was to determine whether disc reduction occurred in patients with closed lock after mandibular manipulation (MM) and to analyze the factors that influenced the result. PATIENTS AND METHODS: Two hundred fifteen patients with closed lock received MM. Of these, 74 patients (79 joints) were assessed by means of magnetic resonance imaging (MRI) for disc reduction. The results of the MRI were compared with the findings from the clinical and radiographic examinations. RESULTS: According to the MRI assessment, only 18% (14 of 79) of the joints had successful disc reduction. The unsuccessfully treated joints had severe joint pain, disc displacement, condylar bone change, and disc deformity. CONCLUSIONS: The results of this study suggest that successful reduction of the disc by MM is rare. They also suggest that MM is least effective in the advanced stages of internal derangement, when the disc becomes deformed.

Adult↗
PubMed1999

Perineuronal nets of proteoglycans in the adult mouse brain are digested by collagenase.

As our previous study has indicated, perineuronal proteoglycans in the adult mouse brain are associated with some collagenous molecules which can be stained with Gömöri's ammoniacal silver and are resistant to hyaluronidase digestion. The present study demonstrated that these molecules are thoroughly digested with collagenase, and suggests that they represent a hyaluronic acid-binding domain of the ligand proteoglycans connecting the perineuronal proteoglycans and nerve cell surface glycoproteins.

Animals↗
PubMed1999

The extracellular matrix in the mouse brain: its reactions to endo-alpha-N-acetylgalactosaminidase and certain other enzymes.

As our previous studies have indicated, the cingulate cortex of the adult mouse brain contains many neurons with rich cell surface glycoproteins which are linked by collagenous ligands to perineuronal proteoglycans. The present study demonstrated that exclusive incubation with endo-alpha-N-acetylgalactosaminidase abolished the lectin Vicia villosa or Wisteria floribunda agglutinin (VVA or WFA) labeling of the nerve cell surface glycoproteins, while it neither interfered with the cationic iron colloid or aldehyde fuchsin stainings of the perineuronal proteoglycans nor abolished the Gömöri's ammoniacal silver impregnation of the collagenous ligands. Double incubations with endo-alpha-N-acetylgalactosaminidase and collagenase did not eliminate the lectin VVA or WFA labeling of the nerve cell surface glycoproteins, though they did eliminate the cationic iron colloid and aldehyde fuchsin stainings of the perineuronal proteoglycans as well as the Gömöri's ammoniacal silver impregnation of the collagenous ligands. Triple incubations with endo-alpha-N-acetylgalactosaminidase, collagenase, and endo-alpha-N-acetylgalactosaminidase abolished the lectin VVA or WFA labeling of the nerve cell surface glycoproteins, and also eliminated the cationic iron colloid and aldehyde fuchsin stainings of the perineuronal proteoglycans and the Gömöri's ammoniacal silver impregnation of the collagenous ligands. These findings indicate that: the nerve cell surface glycoproteins or their terminal N-acetylgalactosamines are digested by endo-alpha-N-acetylgalactosaminidase; these galactosamines associated with the collagenous ligands or perineuronal proteoglycans are not digested by endo-alpha-N-acetylgalactosaminidase; and the terminal N-acetylgalactosamines newly exposed by collagenase incubation are digested by this galactosaminidase. It was further demonstrated that hyaluronidase incubation neither digests the collagenous ligands nor revives the lectin VVA or WFA labeling of the nerve cell surface proteoglycans.

Acetylgalactosamine↗