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Biomedical subjects

T Ishihara

Publications and source records attributed to T Ishihara.

At least 19 recordsLinked to original sources
PubMed1992

(6R)-5,6,7,8-tetrahydro-L-biopterin modulates nitric oxide-associated soluble guanylate cyclase activity in the rat cerebellum.

(6R)-5,6,7,8-Tetrahydro-L-biopterin (R-THBP) is a cofactor not only for aromatic amino acid hydroxylases in mammalian tissues but also for nitric oxide synthase (NOS) induced by endotoxins or cytokines in some kinds of cells. Recently it has been reported that nitric oxide (NO) has biological activity in endothelium and in brain as well. NO activates soluble guanylate cyclase (sGC). Superoxide reacts with NO easily and shortens the half-life of NO actions. We found, in a study using rat cerebellar cytosol fraction, that R-THBP itself did not directly activate sGC, but activated sGC at concentrations ranging from 0.1 to 10 microM only under NO generating conditions of activated NOS and in the presence of sodium nitroprusside. In addition, R-THBP (1 microM) did not alter the NOS activity, which was determined by L-citrulline formation. These results suggest that R-THBP may regulate sGC activity associated with NO formation in the central nervous system.

Animals↗
PubMed1992

Characterization of amyloid fibril protein from a case of cerebral amyloid angiopathy showing immunohistochemical reactivity for both beta protein and cystatin C.

We isolated and carried out a chemical analysis of the amyloid fibril protein from the leptomeningeal vessels of a case with non-hereditary cerebral amyloid angiopathy (CAA) showing dual immunohistochemical reactivity with antibodies to both beta-protein and cystatin C. A crude amyloid fibril fraction reacted only with anti-beta-protein antibody, and cystatin C immunoreactivity was observed in the first PBS supernatant. Complete amino acid sequence of this cystatin C-immunoreactive protein showed a homologous structure to that of normal cystatin C. It is concluded that cystatin C is not an intrinsic component of the amyloid fibril in this type of CAA.

Aged↗
PubMed1992

2-(Carboxycyclopropyl)glycines: binding, neurotoxicity and induction of intracellular free Ca2+ increase.

The excitatory actions of the eight stereoisomers of 2-(carboxycyclopropyl)glycine (CCG), conformationally rigid glutamate analogues, were analyzed for the glutamate receptor subtypes by means of binding assays with rat brain membranes. All CCG isomers inhibited the binding of [3H]3-(2-carboxypiperazine-4-yl)propyl-1-phosphonic acid ([3H]CPP) to N-methyl-D-aspartate (NMDA) receptors. The (2S,3R,4S) isomer (L-CCG-IV) was the most potent agonist for the NMDA receptor and its binding potency was 17- and 790-fold higher than that of L-glutamate and NMDA, respectively. The (2S,3S,4R) isomer (L-CCG-III) showed a potent inhibitory activity for [3H]D-aspartate uptake. Further, L-CCG-IV caused a marked increase of intracellular free Ca2+ concentration [( Ca2+]i) and potent neurotoxicity in the single rat cerebral cortical neurons in vitro, and both were blocked effectively by the NMDA antagonists. Significant correlations were observed between neurotoxicity and the increase of [Ca2+]i and [3H]CPP binding affinity to the NMDA receptor.

Amino Acids, Dicarboxylic↗
PubMed1992

Farber bodies found in murine phagocytes after injection of ceramides and related sphingolipids.

Mice were injected subcutaneously with a single dose of sphingolipids. The sphingolipids tested were: ceramide with alpha-hydroxy fatty acids, ceramide with non-hydroxy fatty acids, glucocerebroside, sphingomyelin, and galactocerebroside. Lipids without sphingolipids served as a control. The mice were sacrificed 1, 2, 3, 4, 5 and 7 days after injection. Three mice were used for each experiment. The subcutaneous tissue at the injected area, the liver and the spleen were studied histologically. At 1-3 days after injection, numerous cytoplasmic inclusion bodies were observed in the macrophages and fibroblasts in the subcutaneous tissue, but not in the liver or the spleen. Ultrastructural studies of the inclusion bodies indicated that the sphingolipids taken up by the phagocytes retained their respective original shape during the 1-3 day stage. At days 4 and 5, the number of the inclusion bodies decreased, but they contained Farber bodies, i.e. curvilinear bodies 12 to 25 nm wide and up to 120 nm long. The mice with galactocerebroside were an exception, with parallel leaflets structures, but without the Farber bodies.

Animals↗
PubMed1992

The prevalence and prognostic significance of arrhythmias in Duchenne type muscular dystrophy.

To investigate the prevalence and prognostic significance of cardiac arrhythmias in Duchenne type muscular dystrophy 24-hour ambulatory ECG was performed in 80 patients with Duchenne type muscular dystrophy, and they were followed up for 5 years. Various arrhythmias were observed in 63.8% (51 of 80) of the patients. Ventricular premature beats were found in 30% (24 of 80), and the incidence of ventricular premature beats increased as the clinical severity of skeletal muscle involvement advanced. Forty-seven patients survived for 5 years, but the incidence of arrhythmias increased from 38.3% (18 of 47) to 74.5% (35 of 47) (p < 0.001). During the 5-year period, four of 33 deaths were sudden. Malignant ventricular premature beats (ventricular couplets, ventricular tachycardia, and R-on-T-type ventricular premature beats) were observed in three of these four patients. It appears that cardiac arrhythmias are a common complication of Duchenne type muscular dystrophy and that the incidence of ventricular arrhythmias increases with the progression of myocardial involvement. There is an association between ventricular arrhythmias and sudden death, but the reduction of ventricular arrhythmias may not reduce the incidence of episodes of sudden death.

Adolescent↗
PubMed1992

A 10-year follow-up study by orthogonal Frank lead ECG on patients with progressive muscular dystrophy of the Duchenne type.

A 10-year follow-up study by orthogonal Frank lead electrocardiography was performed on 25 patients with progressive muscular dystrophy of the Duchenne type (DMD). With advancing age, no apparent changes were observed in the duration and amplitude of the P wave or in the PR interval, whereas the duration of the QRS complex tended to increase. The amplitudes of the R wave in lead X (Rx) and lead Y (Ry) tended to decrease from 1.75 +/- 0.90 and 1.96 +/- 0.59 mV to 0.80 +/- 0.63 and 1.39 +/- 0.62 mV (p < 0.01), whereas the amplitude of the S wave in lead X tended to increase from 0.24 +/- 0.23 mV to 0.53 +/- 0.36 mV in 10 years after initiation of the study (p < 0.01). It is noteworthy that the Ry amplitude began to decrease markedly from the seventh year after the initiation of this study, whereas the Rx amplitude showed a gradual and unceasing decline through the 10-year period. Observation of the sequential changes of the QRS loops in three planes clearly demonstrated that the electrical force tended to decrease in the leftward and inferior directions and increase in the rightward direction. It is of interest that the frequency of occurrence of the deep Q wave was found to be quite high even in the early stages of DMD and that it did not display a direct relation to the sequential evolution of this disease. It can be concluded that observation of the sequential changes in the QRS complex allows estimation of the extent and direction of myocardial involvement in DMD.

Adolescent↗
PubMed1992

Serum growth hormone-binding protein, insulin-like growth factor-I, and growth hormone in patients with liver cirrhosis.

We determined serum growth hormone-binding protein (GHBP), insulin-like growth factor-I (IGF-I), and growth hormone (GH) levels in patients with cirrhosis and in age-matched control subjects, and investigated their relationships. Serum GHBP levels in cirrhotic patients (14.6% +/- 3.9%) (means +/- SD) were significantly lower than those in normal subjects (20.4% +/- 4.7%). GHBP levels had positive correlations with cholinesterase (r = .58, P less than .001) and Normotest (r = .66, P less than .001), both of which represent liver function in cirrhotic patients. Basal GH levels in cirrhotic patients (range, 0.35 to 13.0 micrograms/L; median, 3.9 micrograms/L) were significantly higher than those in normal subjects (0.015 to 6.0 micrograms/L; 0.19 microgram/L). GHBP levels in cirrhotic patients correlated positively with IGF-I levels (r = .39, P less than .01), and negatively with GH levels (r = -.33, P less than .01). These results may indicate that the serum GHBP level reflects the number of hepatic GH receptors, and that the high basal GH level observed in cirrhotic patients is, at least in part, attributable to decreased clearance of GH by these receptors.

Bilirubin↗
PubMed1992

Learning deficits after unilateral AF64A lesions in the rat basal forebrain: role of cholinergic and noncholinergic systems.

Rats were given unilateral infusions of ethylcholine aziridinium ion (AF64A) into the basal forebrain (BF). BF-lesioned rats had significant acquisition and retention deficits in two different types of learning tasks (water maze and active avoidance). Choline acetyltransferase activity was lower than control in the frontal cortex but not in the hippocampus or striatum. AF64A markedly reduced the levels of norepinephrine, dopamine, and serotonin in all brain regions studied. However, L-glutamic acid decarboxylase activity was not altered by AF64A injection. Cholinergic agents (physostigmine and arecoline) ameliorated the AF64A-induced learning deficits in the water maze task but not in the active avoidance task. Noncholinergic agents (desipramine and L-dopa) ameliorated the AF64A-induced avoidance deficits in the active avoidance task but not in the water maze task. 5-Methoxy-N,N-dimethyltryptamine did not improve either active avoidance or water maze learning. These results suggest that intra-BF injection of AF64A produces extensive brain dysfunction and that different neuronal systems are involved in associative and spatial learning.

Animals↗
PubMed1992

Purification and characterization of cathepsin H from hepatopancreas of carp Cyprinus carpio.

1. Cathepsin H was purified about 5400-fold from hepatopancreas of carp (Cyprinus carpio) by the method involving ammonium sulfate fractionation, and chromatography on S-Sepharose, DEAE-Sephacel, Ultrogel AcA54, Concanavalin A-Sepharose 4B and GPC on Protein-Pak 125. 2. The purified cathepsin H gave a single protein band on analytical-PAGE, but migrated as two bands of 27,000 and 23,000 mol. wt on SDS-PAGE. 3. Cathepsin H had a pH and temperature optimum of 6.5 and 45 degrees C using Arg-MCA as a substrate, respectively, and was activated by sulfhydryl compounds and inhibited by cysteine protease inhibitors and metal compounds having high reactivities at cysteine residue. 4. The carp hepatopancreas cathepsin H immunoreacted with the monospecific antibody against rat liver cathepsin H, and did not react with the antibodies against carp hepatopancreas cathepsins B and L by the method of immunoelectrophoretic blotting.

Animals↗
PubMed1992

Functional expression and tissue distribution of a novel receptor for vasoactive intestinal polypeptide.

Vasoactive intestinal polypeptide (VIP), a 28 amino acid peptide hormone, plays many physiological roles in the peripheral and central nerve systems. A functional cDNA clone of the VIP receptor was isolated from a rat lung cDNA library by cross-hybridization with the secretin receptor cDNA. VIP bound the cloned VIP receptor expressed in mouse COP cells and stimulated adenylate cyclase through the cloned receptor. The rat VIP receptor consists of 459 amino acids with a calculated Mr of 52,054 and contains seven transmembrane segments. It is structurally related to the secretin, calcitonin, and parathyroid hormone receptors, suggesting that they constitute a new subfamily of the Gs protein-coupled receptors. VIP receptor mRNA was detected in various rat tissues including liver, lung, intestines, and brain. In situ hybridization revealed that VIP receptor mRNA is widely distributed in neuronal cells of the adult rat brain, with a relatively high expression in the cerebral cortex and hippocampus.

Amino Acid Sequence↗
PubMed1992

Can the chest tube draining the pleural cavity with persistent air leakage be removed?

The pleural drain with persistent air leak in six selected patients after pulmonary surgery was clamped or removed without causing pulmonary collapse. In all the patients, air leak through the chest tube was present when speaking or coughing but not seen when breathing normally at rest or taking deep breaths. The fact that the chest tube could be removed in selected patients is explained by supposing the air leakage through an alveolopleural fistula is dependent on pressure difference between the alveoli and the pleural cavity, and this was confirmed in a rethoracotomy case for persistent air leak. Removal of the chest tube following the above-mentioned rationale would reduce the number of rethoracotomy cases for air leak and facilitate early removal of the chest tube in some patients.

Aged↗
PubMed1992

Growth hormone binding protein in Werner's syndrome.

OBJECTIVE: GH and growth hormone binding protein in Werner's syndrome were investigated to elucidate their relation to the short stature. DESIGN: The levels of GH binding protein and GH response to insulin-induced hypoglycaemia were determined. GH binding protein levels and its Scatchard analysis in Werner's syndrome were compared with those in normal subjects. PATIENTS: Three patients with Werner's syndrome (one man aged 45 years and two women aged 39 and 38 years) and 41 normal subjects (18 men and 23 women aged 39.3 +/- 5.5 years, mean +/- SD) were studied. MEASUREMENTS: GH binding protein levels were determined using an Ultrogel AcA44 minicolumn and GH levels were measured by a highly sensitive enzyme immunoassay. RESULTS: Two out of three patients with Werner's syndrome had GH binding protein levels above the mean +/- 2SD value in normal subjects. GH secretion was impaired in Werner's syndrome as judged by the low GH response to insulin-induced hypoglycaemia. CONCLUSIONS: Elevated GH binding protein levels may lead to an increase in the bound form of GH, which is probably less bioactive, resulting in growth failure in association with the impaired GH secretion in Werner's syndrome.

Adult↗
PubMed1992

An autopsy case of Farber's lipogranulomatosis in a Japanese boy with gastrointestinal involvement.

A boy with Farber's lipogranulomatosis is reported. Excessive ceramide was revealed by thin-layer chromatography of the extracts from the liver. Acid ceramidase activity of the liver was 31.5% of control with exogenous substrate and 33.3% without exogenous substrate. The histological appearance showed granulomatous lesions, composed of spindle or oval-shaped storage cells and proliferation of the connective tissues, in the subcutaneous tissue of the lower lip, periarticular regions and the pericardium. Histochemically the storage cells were revealed to contain lipid and polysaccharide. The foreign body granuloma formed by the surgical suture in the liver was surrounded by a large number of foamy cells. In gastrointestinal mucosa widespread erosion, disappearance of glands and abundant collagen fibers were noted. On electron microscopy, the spindle or oval-shaped cells in the subcutis of the lip had intracytoplasmic inclusions containing granular or fibrillar materials and a smaller number of curvilinear structures, so called "Farber bodies". Our case was a typical clinical and histopathological presentation of Farber's lipogranulomatosis. However, ceramidase activity was higher than in previous descriptions, and severe gastrointestinal lesions and the appearance of a large number of foamy cells around the foreign body granuloma have not been described previously.

Acid Ceramidase↗
PubMed1992

Comparative study of intraneuronal polyglucosan bodies in brains from patients with Lafora disease and aged dogs.

We compared intraneuronal polyglucosan body (PGB) in brains from two patients diagnosed as having Lafora disease and from 18 aged dogs (age range: 10 to 22 years, various breeds). PGBs appeared as various-sized spheroids intensely stained with periodic acid-Schiff (PAS) in both humans and aged dogs. Immunohistochemistry with a monoclonal antibody raised against human polyglucosan showed positive staining of the PGBs. Ultrastructurally, PGBs in both humans and aged dogs were composed of fibril-like structures 4 to 20 nm wide. Electron-dense material formed the central cores of the fibrils, but was also scattered in their peripheral areas. The fibril-like structures were intensely stained upon application of the Thiéry procedure. Immunoelectron microscopy showed that the fibril-like structures were specifically labeled with gold particles. The histological, immunohistochemical and ultrastructural features of the PGBs in humans and aged dogs were quite similar.

Adult↗
PubMed1992

Immunohistochemical and ultrastructural examination of histiocytosis X cells in pulmonary eosinophilic granuloma.

We describe histological, immunohistochemical, and ultrastructural findings in pulmonary eosinophilic granuloma (PEG) from three patients. The specimens were taken by open-lung biopsy. The lesions of the lung were composed of histiocytic cells, macrophages and eosinophils. The histiocytic cells reacted positively with anti-S-100 protein antibody. The histiocytic cells had various types of Birbeck granules in the cytoplasm. The histiocytic cells were histiocytosis X (HX) cells considered to be derived from Langerhans cells. Sporadic mitosis of HX cells was observed. Some HX cells had migrated from the lesions into the alveolar spaces through the alveolar cell layers. In the lesions of PEG, HX cells have self-reproduction and migration capability.

Adolescent↗
PubMed1992

A case of Farber disease.

We report a case of Farber disease (Farber lipogranulomatosis). The main features were a shrill voice, joint swelling, subcutaneous nodules and retarded psychomotor development. Cytological investigation revealed intracytoplasmic inclusion bodies characteristic of Farber disease. Lipid analysis of liver tissue indicated an accumulation of ceramide containing non-hydroxy fatty acids. It was found that the acid ceramidase activity in the liver was reduced to 31% of the control value. In this patient there was also persistent diarrhea, cholelithiasis, transient proteinuria and increased urinary total sialic acids. These features have not been noted in previously reported cases.

Acid Ceramidase↗
PubMed1992

Quantitative Southern blot analysis in the dystrophin gene of Japanese patients with Duchenne or Becker muscular dystrophy: a high frequency of duplications.

Eighty-four unrelated patients with Duchenne or Becker muscular dystrophy in Japan were studied by quantitative Southern blot analysis with dystrophin cDNA probes. We found partial deletions and duplications in 47 (56%) and 12 (14%) cases respectively by HindIII digestion. The duplications were confirmed by BglII digestion and densitometric scanning. The frequency of duplications in this study is significantly higher than those previously reported. This may be because of the small sample number, the racial difference, or our quantitative methods. Our results suggest that attempts to detect duplications are important for a precise diagnosis. Both deletions and duplications clustered at the two hot spots as reported previously. Six cases were exceptions to the 'reading frame hypothesis'. We detected three types of HindIII RFLP. Based on the results of one duplication case, we propose a revised sequential order of exons in the cDNA10 region of the dystrophin gene.

Adolescent↗