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Biomedical subjects

H Sugihara

Publications and source records attributed to H Sugihara.

At least 217 records · Page 12Linked to original sources
PubMed1994

Biochemical characterization of hemorrhagic toxin from Crotalus viridis viridis (prairie rattlesnake) venom.

Hemorrhage, necrosis and edema are some of the effects often observed following snake bites. This paper reports studies on the isolation and biological properties of hemorrhagic toxin from Crotalus viridis viridis (Prairie rattlesnake) venom. A hemorrhagic toxin was isolated from C. v. viridis venom by Sephadex G-50, DEAE-Sephacel and Q-Sepharose column chromatographies. The hemorrhagic toxin from C. v. viridis venom was shown to be homogenous as demonstrated by a single band on polyacrylamide gel electrophoresis and immunodiffusion. Its molecular weight was approximately 54,000 daltons, and it contained 471 amino acid residues. The toxin possessed hemorrhagic activity with a minimum hemorrhagic dose (MHD) of 0.11 micrograms and hydrolytic activity on dimethylcasein, casein, azocasein, azoalbumin, azocoll and hide powder azure. Hemorrhagic and casein hydrolytic activities were inhibited by EDTA, o-phenanthroline or dithiothreitol. The toxin contained 1 mole of zinc per mole of protein and zinc is essential for both hemorrhagic and proteolytic activities. Hemorrhagic toxin possessed hydrolytic activity on the B-chain of insulin, which cleaves His(5)-Leu(6), His(10)-Leu(11), Ala(14)-Leu(15), Tyr(16)-Leu(17) and Phe(24)-Phe(25) bonds. This toxin also hydrolyzed A alpha and B beta chains of fibrinogen. Intramuscular injections of hemorrhagic toxin caused an increase of creatine phosphokinase activity in mice serum from 50.3 mU/ml to 1133 mU/ml. A toxin isolated from C. v. viridis venom was shown to have strong hemorrhagic activity. Partial characterization is reported for this major hemorrhagic toxin in C. v. viridis venom.

Amino Acid Sequence↗
PubMed1994

Characterization and amino-terminal sequence of phospholipase A2-II from the venom of Agkistrodon bilineatus (common cantil).

1. Phospholipase A2 was isolated from the venom of Agkistrodon bilineatus by Sephadex G-75 and CM-Cellulose column chromatographies. 2. The purified phospholipase A2 gave a single band on disc polyacrylamide gel electrophoresis, sodium dodecyl sulfate polyacrylamide gel electrophoresis and ODS-HPLC. 3. The enzyme preparation had a mol. wt of 14,000, isoelectric point of pH 10.12 and possessed 121 amino acid residues. 4. The enzyme hydrolyzed the phospholipids phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl serine. 5. The contraction of mouse diaphragm was inhibited by phospholipase A2-II. 6. Phospholipase A2 activity of this preparation was inhibited by ethylenediamine tetraacetic acid, ethyleneglycol (beta-aminoethyl) N,N,N',N'-tetraacetic acid, p-bromophenacyl bromide or N-bromosuccinimide, but not by iodoacetic acid or diisopropyl fluorophosphate. 7. The amino-terminal sequence of the PLA2-II was determined.

Amino Acid Sequence↗
PubMed1994

Clinical evaluation of hypertrophic cardiomyopathy by myocardial scintigraphy using 123I-labelled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (123I-BMIPP).

To evaluate the clinical utility of 123I-labelled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (123I-BMIPP), myocardial scintigraphy using 123I-BMIPP was performed in 13 patients with hypertrophic cardiomyopathy (HCM), and the findings were compared with those of 201Tl. The uptake of each tracer was scored visually from 4 (increased) to 0 (severely decreased) in a total of 13 segments in the apical and basal short axial images, and the long axial images of myocardial single photon emission tomography (SPET). In the comparison of the early images with 123I-BMIPP (taken 15 min after injection) and the 201Tl perfusion images, 70% of the segments showed uncoupled uptake, with the uptake of 123I-BMIPP more often being less. In the hypertrophic regions, 123I-BMIPP demonstrated significantly less uptake than 201Tl, especially in the delayed images (taken 3 h after injection). In the nonhypertrophic regions, there was no significant difference in uptake between the 123I-BMIPP early images and the 201Tl images; the 123I-BMIPP delayed images, however, demonstrated significantly less uptake than the 201Tl images. These results suggest that the uncoupling between the 123I-BMIPP and 201Tl uptakes and the washout (the relative decrease in activity from early to delayed images of 123I-BMIPP) reflect abnormal myocardial fatty acid metabolism in HCM.

Cardiomyopathy, Hypertrophic↗
PubMed1994

Restoration of growth hormone secretion in prolonged food-deprived rats depends on the level of nutritional intake and dietary protein.

Prolonged food deprivation inhibits GH secretion in rats. To learn more about the nutritional regulation of GH secretion, we observed whether the recovery of GH secretion from prolonged food deprivation depends on the level of nutritional intake or a specific macronutrient in the refeed meal. Adult male Wistar rats were deprived of food for 72 h. Serial blood specimens were withdrawn via an indwelling right atrial cannula every 10 min using an automatic blood-sampling device. In the 72-hour food-deprived rats, the amplitude of the GH pulse progressively decreased but the pulse frequency did not differ compared to that of the fed control rats. When adult male rats were fed 5, 10 or 40 kcal of mixed meal consisting of carbohydrate 60%, protein 25% and fat 15% after 72 h of food deprivation, both the pulse amplitude and the pulse frequency immediately increased compared to those of the fasted control rats. Following these changes, the pulsatility of GH secretion was restored to normal, while the pulse amplitude was recovered in a meal-size-dependent manner. The GH secretory pattern no longer differed from that of the fed control rats in the rats fed 40 kcal of mixed meal. In the second study, the 72-hour food-deprived rats were fed 10 or 40 kcal of a protein meal consisting only of casein powder or 40 kcal of a protein-deficient meal consisting of carbohydrate 85% and fat 15%. The GH secretory pattern was restored to normal among the food-deprived rats fed 40 kcal of a protein meal.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity Cycles↗
PubMed1994

Growth hormone induces expression of the c-fos gene on hypothalamic neuropeptide-Y and somatostatin neurons in hypophysectomized rats.

The neuronal expression of the protooncogene c-fos may serve as a marker of neural activity. We previously examined brain sites upon which GH exerts an immediate early influence in rats and determined that the c-fos gene was transiently expressed in the hypothalamic periventricular nucleus (PeV) and arcuate nucleus (ARC) after recombinant human GH (rhGH) administration. As the distribution of c-fos messenger RNA (mRNA)-containing cells appeared to overlap with that of somatostatin (SS) neurons in both the PeV and ARC, we hypothesized that GH exerts a feedback effect on hypothalamic SS neurons. To extend this hypothesis, we characterized the neurons expressing the c-fos gene in response to rhGH administration in hypophysectomized rats. Adult male Wistar rats were hypophysectomized 10 days before use. After hypophysectomy, rats received daily sc injections of cortisone acetate (0.5 mg/kg BW) and L-T4 (20 micrograms/kg BW). Four international units (1.33 mg) of rhGH were given iv through an indwelling right atrial cannula. The vehicle was given to the control animals. Coronal sections of the hypothalamus were processed for in situ hybridization after rhGH or vehicle administration. To estimate the localization of neurons expressing the c-fos gene, the adjacent hypothalamic sections, 30 microns in thickness, were processed for hybridization histochemistry for SS, neuropeptide-Y (NPY), or GRF mRNA. In the ARC, the distribution of c-fos mRNA-containing cells appeared to overlap with that of NPY and partially with that of SS mRNA-containing cells, but it clearly differed from the distribution of GRF mRNA-containing cells. In the PeV, distribution of the cells expressing the c-fos gene was comparable to that of SS mRNA-containing cells. To further ascertain the distribution, hypothalamic sections, 6 microns in thickness, were processed by double label in situ hybridization using a 35S-labeled c-fos cRNA probe and a digoxigenin-labeled NPY or SS cRNA probe. In the ARC, 65% of the c-fos gene-expressing cells were NPY neurons. In the PeV, 60% of the c-fos gene-expressing cells were SS neurons. NPY is known to act within the hypothalamus and inhibit GH secretion via SS in rats, and the NPY neurons in the ARC have been shown to project to SS neurons in the PeV. Our findings suggest that the feedback effect of GH on the hypothalamus is mediated not only by SS neurons in the PeV, but also by NPY neurons in the ARC.

Animals↗
PubMed1994

Synthesis and platelet-activating factor (PAF)-antagonistic activities of 1,4-disubstituted piperazine derivatives.

During the screening of novel platelet-activating factor (PAF) antagonists, we found that 1-(6-methoxy-3,4-dihydro-2-naphthoyl)-4- (3,4,5-trimethoxybenzyl)piperazine and its 4-(3,4,5- trimethoxybenzoyl)piperazine derivatives (1b, 2b) exerted in vitro and in vivo PAF-antagonistic activities. Modifications of the 1-acyl group, the substituent at the 4-position and the piperazine ring of 1a and 2b were examined and from this series 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8-ylcarbonyl++ +)-4- (3,4,5-trimethoxybenzoyl)piperazine (2g) was found to be one of the most potent PAF antagonists.

Animals↗
PubMed1994

Synthesis and platelet-activating factor (PAF)-antagonistic activities of trisubstituted piperazine derivatives.

2- or 3-Substituted 1-(2,3-dimethoxy-6,7-dihydro-5H-benzocyclohepten-8- ylcarbonyl)-4-(3,4,5-trimethoxybenzoyl)- and 4-(3,4,5-trimethoxybenzyl)piperazines (2a-s, 3a, b) were prepared and evaluated for antagonistic activities against platelet-activating factor (PAF)-induced platelet aggregation and blood pressure reduction. The 2-methoxymethyl derivative (2f) showed the most potent activities in this series. The enantiomers (R)-(+)-2f and (S)-(-)-2f were synthesized from carbobenzoxy-O-benzyl-L- and D-serine in several steps. In the binding experiment, (S)-(-)-2f showed thirty times greater affinity than the R isomer for the PAF receptor.

Animals↗
PubMed1994

Synthesis and angiotensin converting enzyme-inhibitory activity of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives.

As part of a search for potent and long-lasting angiotensin converting enzyme (ACE) inhibitors, various types of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives (7a, 8-11) were prepared. The key synthetic intermediate, N-[(1S)-5-(1-benzyloxycarbonyl-4-piperidyl)-1- ethoxycarbonylpentyl]-L-alanine (17a), was synthesized by asymmetric reduction of the alpha-oxoester (13) with Lactobacillus paracasei subsp. paracasei followed by a substitution reaction with tert-butyl L-alaninate (15) and subsequent treatment with hydrogen chloride. Compounds 7a and 8-11 showed potent and long-lasting ACE-inhibitory activity in rats.

Alanine↗
PubMed1994

[Assessment of left ventricular count increase with ECG-gated 99mTc-MIBI SPECT using a single-head rotating gamma-camera].

ECG-gated 99mTc-MIBI SPECT was performed in 33 patients, including 17 normal subjects and 16 patients with old myocardial infarction. To compare the findings by echocardiography (UCG), regional wall motion was qualitatively assessed by cine-mode display and quantitatively measured as an increase in regional count from end-diastole to end-systole. The percent count increase and relative count increase was measured to display on the Bull's eye polar map. In the study of normal subjects, the count increase was greater in apical regions and smaller in septal regions. Regional wall motion by this method correlated well with UCG findings (agreement: 97%, complete agreement: 60%). A mild but significant correlation was observed between the count increase by this method and the percent wall thickening by UCG. We conclude that regional wall motion can be accurately evaluated with ECG-gated 99mTc-MIBI SPECT, which thus permits simultaneous assessment of regional wall motion and myocardial perfusion.

Aged↗
PubMed1994

[Detection of myocardial viability by delayed imaging after 201Tl reinjection].

Recent studies have demonstrated that some underestimation of myocardial viability remained to be not resolved even using reinjection method. So we devised a new technique of reinjection and reimaging, and using this we studied the detectability of myocardial viability in 32 patients of CAD. Exercise imaging (EX) was acquired after initial injection of thallium (111 MBq). Three hours after EX, the second dose thallium (37 MBq) was reinjected, and then the first reinjection image (Re1) was performed. Furthermore, the second reinjection image (Re2) was obtained at 3 hours after the second dose reinjection. SPECT images were divided in basal, mid and apical parts, and totally 13 segments were analyzed by visual scoring (0: severe, 1:moderate, 2:mild hypoperfusion and 3:normal). Twenty-seven (13.4%) of 202 segments of low score (0 to 2) shown in EX were improved in Re2, compared with Re1. Twenty-one (42.0%) of 50 segments of score 0 or 1 shown in Re1 were improved in Re2. These results showed that our devised new method of reimaging 3 hours after the second dose injection was useful to improve in detectability of myocardial viability.

Aged↗
PubMed1994

[Evaluation of myocardial perfusion and ventricular shape in hypertrophic cardiomyopathy using 99mTc-tetrofosmin scintigraphy: comparison with 201Tl myocardial scintigraphy].

Hypertrophic cardiomyopathy (HCM) is known to have the impairment of myocardial perfusion as well as irregularly hypertrophic myocardium. To evaluate myocardial perfusion and ventricular shape in HCM, 99mTc-Tetrofosmin scintigraphy was performed after exercise (Ex) and at resting state (Re) in 10 patients with HCM and was compared with early image (Ea) and delayed image (De) of 201Tl scintigraphy performed after exercise. SPECT images of both 99mTc-Tetrofosmin and 201Tl scintigraphy were analyzed with five scaled visual scores set in 18 segments. The complete concordance ratio between 99mTc-Tetrofosmin (Ex and Re) and 201Tl (Ea and De) images in segmental analysis was 75%. Image quality of 99mTc-Tetrofosmin was seemed to be superior to that of 201Tl scintigraphy. In 9 patients with HCM, 99mTc-Tetrofosmin scintigraphy was performed under the ECG gating and the thickness of septal and free wall was measured. Good correlation was observed with the data by ultrasound cardiography (r = 0.79, p < 0.002 in wall thickness, r = 0.84, p < 0.01 in the ratio of septal wall thickness to free wall thickness). Left ventricular shape (ventricular long axis) was closely resemble to that of left ventriculography by contrast medium. In conclusion, 99mTc-Tetrofosmin scintigraphy is useful for the evaluation of myocardial morphology as well as perfusion abnormality.

Adult↗
PubMed1993

Autopsy report of acute necrotizing opticomyelopathy associated with thyroid cancer.

We report an autopsied case of paraneoplastic necrotizing myelopathy. The patient had bilateral blindness, quadriplegia, and dyspnea of acute onset and died without remission 7 weeks later. The severe tissue necrosis and demyelination were found in the optic chiasm and from the medulla oblongata throughout the whole length of spinal cord. A papillary carcinoma was found in the thyroid gland at autopsy. In the present case IgG, myelin basic protein and activated helper T cells were increased in the CSF at onset, suggesting a mechanism of autoimmune demyelination for the condition.

Autoimmune Diseases↗
PubMed1993

Immunohistochemical localization of a metabotropic glutamate receptor, mGluR5, in the rat brain.

A trpE-fusion protein containing a C-terminal sequence of a rat metabotropic glutamate receptor, mGluR5, was used to produce an antibody. On immunoblot, the antibody specifically reacted with mGluR5 expressed in mammalian cells and rat brain. Immunohistochemical analysis revealed intense mGluR5-like immunoreactivity (LI) in the olfactory bulb, anterior olfactory nuclei, olfactory tubercle, cerebral cortex, hippocampus, lateral septum, striatum, nucleus accumbens, inferior colliculus, and spinal trigeminal nuclei. The distribution pattern of mGluR5-LI corresponds very well with that of mGluR5 mRNA. Electron microscope analysis of the striatum revealed dense accumulation of immunoreaction products in dendrites which were often provided with asymmetrical synapses. These results suggest that mGluR5 is predominantly located in postsynaptic elements.

Animals↗
PubMed1993

Developmental expression of the growth hormone receptor gene in the rat hypothalamus.

The ontogeny of growth hormone receptor (GHR) gene expression was studied in the rat hypothalamus. Total RNA from the hypothalamus of rats at different developmental stages (embryonic day 15-56 days of age) was characterized using a 32P-labeled RNA probe derived from the extracellular domain of the rat GHR cDNA. Two RNA species, 4.5 kilobases (kb) encoding for GHR and 1.2 kb encoding for GH-binding protein, were detected in hypothalamic tissue from embryonic day 15 to 56 days of age. Their levels were low at embryonic day 15 and increased toward 3 days of age. The level of 4.5-kb transcript preferentially increased from 7 days after birth, and it was maintained until 35 days of age. Thereafter, the level of 4.5-kb transcript declined. The ratio between the 4.5- and 1.2-kb transcripts was less than 2.0 from embryonic day 15 to 3 days after birth, while it was larger than 4 after 7 days of age. There was no sex difference in the levels or the ratios of the transcripts of the GHR gene from 7 to 56 days of age. The findings indicate that the 4.5-kb transcript preferentially processed postnatally in the rat hypothalamus.

Animals↗
PubMed1993

Progression of signet ring cell carcinomas in the human stomach.

BACKGROUND: Stomach cancers show various growth patterns. It remains to be clarified how this variability is related to the genetic changes that occur during tumor progression. METHODS: To estimate the genetic changes from tumor ploidy, maps were made (using DNA cytofluorometry of metaphase cells in histologic sections) of 39 advanced signet ring cell carcinomas of the human stomach and correlated with tumor stage and the size of the primary mucosal lesion. RESULTS: Aneuploid area and multipattern aneuploidy were particularly common in advanced cancers with primary mucosal lesions smaller than 2 cm in diameter, of which a large portion were predominantly aneuploid and already diffusely infiltrating. As the tumor stage advanced, the incidence of aneuploidy in the mucosal lesion increased, whereas predominantly aneuploid tumors were less common as primary mucosal lesions became larger. Purely diploid areas with an incidence of polyploidy as low as in early cancers were common in advanced cancers. In addition, there were diploid-appearing cancer cells that infiltrated diffusely and were accompanied by polyploid as often as aneuploid cells. Some of these were aneuploid at the chromosomal level. CONCLUSIONS: In signet ring cell carcinoma, aneuploid cells show higher invasive activity toward the extramucosal part and may occur incidentally in originally diploid tumors, depending on the degree of genetic instability. An analysis of polyploidy is useful for differentiating cytometrically diploid (but actually, aneuploid) cells from diploid cells with minor genetic abnormalities.

Adenocarcinoma, Mucinous↗
PubMed1993

Molecular characterization of the family of the N-methyl-D-aspartate receptor subunits.

cDNA clones for four different N-methyl-D-aspartate (NMDA) receptor subunits (NMDAR2A-NMDAR2D) were isolated through polymerase chain reactions followed by molecular screening of a rat brain cDNA library. These subunits are only about 15% identical with the key subunit of the NMDA receptor (NMDAR1) but are highly homologous (approximately 50% homology) with one another. They also commonly possess large hydrophilic domains at both amino- and carboxyl-terminal sides of the four putative transmembrane segments. NMDAR2A and NMDAR2C expressed individually in Xenopus oocytes showed no electrophysiological response to agonists. However, these subunits in combined expression with NMDAR1 markedly potentiated the NMDAR1 activity and produced functional variability in the affinity of agonists, the effectiveness of antagonists, and the sensitivity to Mg2+ blockade. Thus, NMDAR1 is essential for the function of the NMDA receptor, and multiple NMDAR2 subunits potentiate and differentiate the function of the NMDA receptor by forming different heteromeric configurations with NMDAR1. Northern blotting and in situ hybridization analyses revealed that the expressions of individual mRNAs for the NMDAR2 subunits overlap in some brain regions but are also specialized in many other regions. This investigation demonstrates the anatomical and functional differences of the NMDAR2 subunits, which provide the molecular basis for the functional diversity of the NMDA receptor.

Amino Acid Sequence↗
PubMed1993

Kallidin-releasing enzyme from Bitis arietans (puff adder) venom.

A kallidin-releasing enzyme with arginine ester hydrolytic activity was isolated from Bitis arietans venom by Sephadex G-75, DEAE-cellulose, and Sephadex G-100 column chromatography. This enzyme was shown to be homogeneous as demonstrated by a single band on polyacrylamide gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and NH2-terminal sequence analysis. The molecular weight was determined to be 58,000 Da with an isoelectric point of 4.4. Kallidin-releasing enzyme possesses proteolytic activity demonstrated by the hydrolysis of Gly(8)-Ser(9), Ala(14)-Leu(15), Tyr(16)-Leu(17), and Phe(25)-Tyr(26) bonds of oxidized insulin B chain. This enzyme did not convert fibrinogen to fibrin, yet it did hydrolyze the A alpha, B beta, and gamma chains of fibrinogen. The enzyme was shown to cleave a kininogen analog with the release of kallidin. Arginine ester hydrolytic activity of the preparation was inhibited by diisopropyl fluorophosphate and benzamidine hydrochloride, suggesting that serine and glutamic acid or aspartic acid are involved in this activity. This protein was stable to heat and over the pH range of 3-12.

Amino Acid Sequence↗