Biomedical subjects

M Shinoda

Publications and source records attributed to M Shinoda.

At least 127 records · Page 7Linked to original sources

PubMed1994

[A case of malignant lymphoma, highly suspected to be of pancreatic origin, with multiple nodular hepatic invasions].

We reported a rare case of malignant lymphoma, highly suspected to be of pancreas origin with multiple nodular hepatic invasions. A 63-year-old man visited our hospital on May 24 1990, complaining of anorexia. In spite of high serum levels of LDH and amylase, abdominal ultrasonography (US) showed no significant lesions. Forty days later, he was admitted because of the loss of weight and the appearance of abdominal pain with marked hepatomegaly, exhibiting cachexia. Abdominal US and computed tomography visualized a tumor of pancreas with multiple nodular space-occupying lesions in the liver. In several days, jaundice and ascites appeared with progressive deterioration. Angiography showed no tumor vascularity nor vascular stain in pancreas and liver, suggesting a non-epithelial malignancy. Mitomycin C and Epi-adriamycin, given to the patient via the celiac artery, brought about a remarkable shrinkage of the abdominal tumor. Subsequent systemic chemotherapies and occasional intra-arterial chemotherapies resulted in the disappearance of abdominal tumor clinically. However, at the end of April 1991, signs of CNS involvement were observed, and he died on June 7, 1991. Autopsy revealed that malignant lymphoma, of diffuse large cell type, had invaded the subarachnoidal cavity without any evidence of invasion of the abdomen or other sites except regional necrotic lesion in the pancreas. These findings strongly suggested that the patient suffered from malignant lymphoma of pancreas origin with multiple nodular hepatic invasions.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1993

Effects of a novel thyrotropin-releasing hormone analogue, JTP-2942, on extracellular acetylcholine and choline levels in the rat frontal cortex and hippocampus.

The effects of a novel thyrotropin-releasing hormone (TRH) analogue, N alpha-[(1S,2R)-2-methyl-4-oxocyclopentanecarbonyl]-L-histidyl-L-pr olinamide (JTP-2942) on acetylcholine (ACh) release and on the extracellular choline level were investigated in rat frontal cortex and hippocampus by microdialysis, and were compared with effects of TRH. JTP-2942 (0.3 mg/kg i.p.) produced a marked (> 300%) and persistent increase of ACh release in both the frontal cortex and hippocampus, while TRH (3 mg/kg i.p.) caused a significant but transient increase of ACh to about 200% in the frontal cortex. Both drugs significantly decreased the choline levels in both brain regions. Investigation of the effects of JTP-2942 (0.001-1 mM) and TRH (1 and 10 mM) on ACh release and choline levels when perfused through the dialysis probe revealed that JTP-2942 had a greater effect than TRH in both the frontal cortex and the hippocampus. The action of JTP-2942 was about 1000-fold more potent than that of TRH in both brain regions. Oral administration of JTP-2942 at a dose of 10 mg/kg markedly and persistently increased the release of ACh and at doses of 1-10 mg/kg decreased the extracellular choline level in the frontal cortex and hippocampus. These results also suggest that JTP-2942 has some selectivity for the hippocampus compared to the frontal cortex after both systemic administration and local injection. The increase of ACh release caused by JTP-2942 was completely antagonized by perfusion with tetrodotoxin (TTX, 1 microM), suggesting that the action of JTP-2942 on cholinergic neurons was mediated via neuronal activity.

Acetylcholine↗

PubMed1993

Development of akinetic mutism and hyperphagia after left thalamic and right hypothalamic lesions.

A case of childhood post-traumatic akinetic mutism is presented. The patient showed a hyperphagic condition while recovering from akinetic mutism. He had lesions in the left interlaminal nucleus of the thalamus, right globus pallidus, and right dorsomedial nucleus of the hypothalamus. Laboratory data indicated slightly disturbed hypothalamic functions. In general, akinetic mutism can be seen with bilateral destructive lesions, while hyperphagia may occur after destruction of dorsomedial hypothalamic nucleus, but it is very rare. This is the first reported case of akinetic mutism caused by a unilateral lesion.

Akinetic Mutism↗

PubMed1993

Crystallization and preliminary X-ray diffraction studies of a mammalian steroid dehydrogenase.

20 beta-Hydroxysteroid dehydrogenase from the cytosolic fraction of neonatal pig testis is a NADPH-dependent enzyme that catalyzes the reduction of the C-20 ketone of C21-steroids. It is 85% homologous in amino acid sequence to the human enzyme, carbonyl reductase. The enzyme has been crystallized from 36% saturated ammonium sulfate in 10 mM 2-[N-Morpholino]ethanesulfonic acid buffer. The size and the quality of nicely formed square bi-pyramidal crystals were improved by using a "seeding" technique. The crystals diffract X-rays to at least 2.5 A resolution. The space group is P4(1)2(1)2 (or P4(3)2(1)2) and the unit-cell dimensions are a = b = 58.53 A, c = 165.64 A. There is one molecule (M(r) = 30.5 kDa; 289 amino acid residues) in the asymmetric unit. An intensity data set to 2.5 A has been collected with an overall Rmerge of 6.6% for all reflections.

Animals↗

PubMed1993

[Protective effects of Taiwan crude drugs on experimental liver injuries].

Protective effects of 41 Taiwan crude drugs on rat hepatic injuries caused by carbon tetrachloride (CCl4) and alpha-naphthylisothiocyanate (ANIT) were investigated. The methanol extracts of Elephantopi Herba and Lonicerae Flos inhibited the release of intrahepatic enzymes and histological changes by CCl4. The methanol extracts of Canarii Radix, Arecae Pericarpium, Cynomorii Caulis, Polygoni Cuspidati Radix, Phyllodii Herba, Junci Caulis Medulla, Rubiae Herba and Rhinacanthi Herba protected the hepatic injury by ANIT. Among them, the water extracts of Cymorii Caulis and Junci Caulis Medulla showed higher protective potency than the methanol extracts. And them this two crude drugs also protected the cholestasis by ANIT.

1-Naphthylisothiocyanate↗

PubMed1993

[Purification of pig adrenal 3 beta-hydroxysteroid dehydrogenase/isomerase and influence on microsomal membrane destruction on its enzyme activity].

A 3 beta-hydroxysteroid dehydrogenase/delta 4-delta 5-isomerase (3 beta-HSD/isomerase) has been purified to homogeneity from the pig adrenal microsomes by solubilization with sodium cholate, followed by some conventional column chromatographies. The molecular weight of the enzyme was estimated to be 42000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Km value for pregnenolone as the substrate of the purified enzyme was higher than that of the microsomal enzyme. The purified enzyme was less stable for heat treatment than the microsomal binding enzyme. The microsomal enzyme was treated with various agents or enzymes which destroyed the membrane structure. Lipid peroxidation with Fe2+, digestion with phospholipase A2 or C, and the addition of various free fatty acids, imidazole containing compounds and polymyxin B were utilized for the membrane destruction. Consequently, the 3 beta-HSD/isomerase activity was significantly reduced in all cases, and the Km value of the 3 beta-HSD/isomerase for pregnenolone increased. And the Vmax and Vmax/Km values significantly decreased. Therefore, it is strongly suggested that the normal membrane structure plays an important role in the maintenance of the 3 beta-HSD/isomerase activity.

3-Hydroxysteroid Dehydrogenases↗

PubMed1992

Pig testicular 20 beta-hydroxysteroid dehydrogenase exhibits carbonyl reductase-like structure and activity. cDNA cloning of pig testicular 20 beta-hydroxysteroid dehydrogenase.

cDNA inserts encoding 20 beta-hydroxysteroid dehydrogenase (EC 1.1.1.53) were, for the first time, isolated and cloned from a pig testis cDNA library using synthetic oligonucleotides deduced from the partially determined amino acid sequences. The cDNA contains an open reading frame predicted to encode 289 amino acid residues. Surprisingly, it has 85% amino acid homology to human carbonyl reductase. The purified enzyme exhibited carbonyl reductase activity. Adenine-rich sequence was located in the 3'-untranslated nine-rich sequence was located in the 3'-untranslated region, which may mean that the gene originates by retroposition. RNA transcripts of 1.3, 3, and 6 kilobases were detected in poly(A)+ RNA extracted from pig testis by Northern blot hybridization. The steady-state level of the RNA species increased to a maximum in testes from 10-day-old pigs, but rapidly declined thereafter to the same levels found in testes of mature animals.

Alcohol Oxidoreductases↗

PubMed1992

Chemical modification of cysteinyl, lysyl and histidyl residues of mouse liver 17 beta-hydroxysteroid dehydrogenase.

Monomeric 17 beta-hydroxysteroid dehydrogenase from mouse liver was rapidly inactivated by 5,5'-dithiobis(2-nitrobenzoic acid) and 2,4,6-trinitrobenzene-1-sulfonate, and the absorption spectra of the inactivated enzymes indicated that cysteine and lysine residues were modified. The kinetics of inactivation and spectrophotometric quantification of the modified residues suggested that complete inactivation was caused by modification of two cysteine residues or one lysine residue per active site. The inactivation by the two reagents was protected by NADP+ and some coenzyme analogs, but not by a steroid substrate, testosterone. Moreover, chemical modification by diethyl pyrocarbonate also produced inactivation of the enzyme, and showed a difference spectrum with a peak at 242 nm characteristic of N-carbethoxyhistidine residues, which decreased with the addition of hydroxylamine. The inactivation by this reagent, following pseudo-first-order kinetics, was protected partially by either NADP+ or testosterone and completely in the presence of both the coenzyme and substrate. The results suggest the presence of essential cysteine and lysine residues at or near the coenzyme-binding site and that of essential histidine residue(s) in the catalytic region of the active site of mouse liver 17 beta-hydroxysteroid dehydrogenase.

17-Hydroxysteroid Dehydrogenases↗

PubMed1992

Malignant lymphoma of mucosa-associated lymphoid tissue arising in the thymus of a patient with Sjögren's syndrome. A morphologic, phenotypic, and genotypic study.

A 59-year-old woman with Sjögren's syndrome had an anterior mediastinal tumor. The tumor had epithelium-lined thymic cysts. Histologically, centrocyte-like (CCL) cells were present as clusters intermingling with small lymphocytes and plasma cells, invaded the epithelium, and formed characteristic lymphoepithelial lesions; the tumor was identified as malignant lymphoma arising in mucosa-associated lymphoid tissue (MALT). Within the tumor, trapped Hassall's corpuscles were recognized. Immunohistochemical staining demonstrated monotypic cytoplasmic kappa light chains in a small portion of the CCL cells. Furthermore, Southern blot hybridization studies showed rearrangements of immunoglobulin heavy chain, immunoglobulin kappa light chain, and T-cell receptor beta genes. The findings are consistent with thymic low-grade B-cell MALT lymphoma.

Cytoplasm↗

PubMed1992

Single photon emission computerized tomography in childhood hydrocephalus.

Single photon emission computerized tomography (SPECT) is now widely used as one of the tools in evaluating cerebral blood flow (CBF). The authors report the CBF changes in childhood hydrocephalus. Five pediatric cases studied by 123I-IM SPECT in children are presented. The authors counted radioactivities both in early and delayed images in each patient, and calculated the reabsorption ratio (RR). Two negative-RR cases and three positive-RR cases were found. All of the negative-RR patients had a poor prognosis, while all of the positive-RR patients had a favorable outcome.

Cerebrovascular Circulation↗

PubMed1992

Ontogeny of testicular steroid dehydrogenase enzymes in pig (3 alpha/beta-, 20 alpha- and 20 beta-): evidence for two forms of 3 alpha/beta-hydroxysteroid dehydrogenase.

Three enzymatic activities (3 alpha/beta-hydroxysteroid dehydrogenase, 20 beta- and 20 alpha-hydroxysteroid dehydrogenases) were measured in testes of pigs as a function of age. Earlier studies reported a highly purified 20 beta-hydroxysteroid dehydrogenase from neonatal pig testes that also showed strong 3 alpha/beta-hydroxysteroid dehydrogenase activity [Ohno et al., J. Steroid Biochem. Molec. Biol. 38 (1991) 787-794]. We report here that neonatal pigs testis is rich in 3 alpha/beta- and 20 beta-hydroxysteroid dehydrogenase activities, both of which fall to low levels (measured as specific activity) at 60 days. Thereafter the activity of 3 alpha/beta-reduction rises to high levels whereas 20 beta-reduction remains low. Activity of 20 alpha-reduction is of intermediate level in the neonate, falls to a nadir at 60 days and rises to high levels in the mature animal. Western blots of cytosolic proteins show that the bifunctional enzyme (3 alpha/beta-plus 20 beta-hydroxysteroid dehydrogenase) is high in neonatal testes and falls to low levels at maturity. It is proposed that the neonatal testis possesses the bifunctional enzyme which is replaced by a second enzyme at maturity, that is a 3 alpha/beta-hydroxysteroid dehydrogenase without 20 beta-reductase activity. The possible functional significance of these changes is considered.

20-Hydroxysteroid Dehydrogenases↗

PubMed1992

3 alpha-hydroxysteroid dehydrogenase activity catalyzed by purified pig adrenal 20 alpha-hydroxysteroid dehydrogenase.

In earlier studies, two distinct molecules, 20 alpha-HSD-I and 20 alpha-HSD-II, responsible for 20 alpha-HSD activity of pig adrenal cytosol were purified to homogeneity and characterized [S. Nakajin et al., J. Steroid Biochem. 33 (1989) 1181-1189]. We report here that the purified 20 alpha-HSD-I, which mainly catalyzes the reduction of 17 alpha-hydroxyprogesterone to 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one, catalyzes 3 alpha-hydroxysteroid oxidoreductase activity for 5 alpha (or 5 beta)-androstanes (C19), 5 alpha (or 5 beta)-pregnanes (C21) in the presence of NADPH as the preferred cofactor. The purified enzyme has a preference for the 5 alpha (or 5 beta)-androstane substrates rather than 5 alpha (or 5 beta)-pregnane substrates, and the 5 beta-isomers rather than 5 alpha-isomers, respectively. Kinetic constants in the reduction for 5 alpha-androstanedione (Km; 3.3 microM, Vmax; 69.7 nmol/min/mg) and 5 beta-androstanedione (Km; 7.7 microM, Vmax; 135.7 nmol/min/mg) were demonstrated for comparison with those for 17 alpha-hydroxyprogesterone (Km; 26.2 microM, Vmax; 1.3 nmol/min/mg) which is a substrate for 20 alpha-HSD activity. Regarding oxidation, the apparent Km and Vmax values for 3 alpha-hydroxy-5 alpha-androstan-17-one were 1.7 microM and 43.2 nmol/min/mg, and 1.2 microM and 32.1 nmol/min/mg for 3 alpha-hydroxy-5 beta-androstan-17-one, respectively. 20 alpha-HSD activity in the reduction of 17 alpha-hydroxyprogesterone catalyzed by the purified enzyme was inhibited competitively by addition of 5 alpha-DHT with a Ki value of 2.0 microM. Furthermore, 17 alpha-hydroxyprogesterone inhibited competitively 3 alpha-HSD activity with a Ki value of 150 microM.

20-Hydroxysteroid Dehydrogenases↗

PubMed1992

Demyelinating peripheral neuropathy in Cockayne syndrome: a histopathologic and morphometric study.

The clinical and histopathological features of Cockayne syndrome in a 2-year-old girl are reported. Sural nerve biopsy revealed segmental demyelination and remyelination. The density of myelinated fibers, especially small ones, was decreased in comparison with an age-matched control. Although the total number of unmyelinated fibers showed no difference from that in the control, the number of small unmyelinated fibers was slightly increased. A study of teased fibers from the patient's nerve revealed that 1% of the fibers had segmental demyelination, and 7% showed remyelination. Ultrastructurally, demyelinated fibers were present sporadically. No degeneration of axons was evident. Our pathological and morphometric data for the sural nerve suggest the presence of primary demyelination in early childhood.

Child, Preschool↗

PubMed1992

Modification of pig liver dimeric dihydrodiol dehydrogenase with diethylpyrocarbonate and by rose bengal-sensitized photooxidation: evidence for an active-site histidine residue.

Dihydrodiol dehydrogenase from pig liver was inactivated by diethylpyrocarbonate (DEP) and by rose bengal-sensitized photooxidation. The DEP inactivation was reversed by hydroxylamine and the absorption spectrum of the inactivated enzyme indicated that both histidine and tyrosine residues were carbethoxylated. The rates of inactivation by DEP and by photooxidation were dependent on pH, showing the involvement of a group with a pKa of 6.4. The kinetics of inactivation and spectrophotometric quantification of the modified residues suggested that complete inactivation was caused by modification of one histidine residue per active site. The inactivation by the two modifications was partially prevented by either NADP(H) or the combination of NADP+ and substrate, and completely prevented in the presence of both NADP+ and a competitive inhibitor which binds to the enzyme-NADP+ binary complex. The DEP-modified enzyme caused the same blue shift and enhancement of NADPH fluorescence as did the native enzyme, suggesting that the modified histidine is not in the coenzyme-binding site of the enzyme. The results suggest the presence of essential histidine residues in the catalytic region of the active site of pig liver dihydrodiol dehydrogenase.

Alcohol Oxidoreductases↗

PubMed1992

Inhibition of dimeric dihydrodiol dehydrogenase by 4-hydroxyphenylketone derivatives: aspects of inhibitor structure and binding specificity.

Dimeric dihydrodiol dehydrogenases from pig liver, monkey kidney, and rabbit lens were inhibited more potently by 4-hydroxyphenylketones such as 4-hydroxybenzaldehyde, 4-hydroxyphenylglyoxal, and 4-hydroxyacetophenone than by isoascorbate and ascorbate, known inhibitors of the enzymes. No significant inhibition was observed with 2- or 3-hydroxyphenylketones, phenylketones with a functional group other than a hydroxy group at the 4-position, and 4-hydroxyphenyl derivatives without a carbonyl group. The steady-state kinetic analyses of the inhibition of the pig liver enzyme indicated that the 4-hydroxyphenylketones, similarly to ascorbate and its epimer, bound to an enzyme-NADP+ binary complex as competitive inhibitors with respect to dihydrodiol substrate. The inhibition by the 4-hydroxyphenylketones was uncompetitive with respect to isoascorbate, and the addition of one of the 4-hydroxyphenylketones or isoascorbate with NADP+ afforded a great protective effect against inactivation of the enzyme by diethylpyrocarbonate or by heat treatment, which indicates that 4-hydroxyphenylketones and isoascorbate bind at the same site in or near the active center of the enzyme. The structural comparison of 4-hydroxybenzaldehyde and ascorbate suggests that the hydroxy group at C-5, carbonyl group at C-1 and lactone ring of ascorbate are important for the binding to the enzyme.

Alcohol Oxidoreductases↗

PubMed1992

Studies on chemical protectors against radiation. XXXV. Effects of radioprotective Chinese traditional medicines on radiation-induced lipid peroxidation in vivo and in vitro.

The fluctuation of lipid peroxidation (LP) in 9 tissues was investigated in mice for 7 d after whole-body X-irradiation with a lethal dose of bone marrow death. LP increased significantly in bone marrow, thymus, spleen and liver following irradiation, and slightly in brain and testis, but not in blood plasma, submaxillary gland or kidney. The effects of 7 radioprotective Chinese traditional medicines (CTMs) and cysteamine (MEA) on the radiation-induced LP in 4 tissues were studied by i.p. injection before or after irradiation and their LP content in tissues was measured 2 d after irradiation. Most CTMs showed significant inhibition of radiation-induced LP in bone marrow and liver, especially when injected prior to irradiation. Some CTMs also showed such inhibition in spleen. MEA only inhibited the increase of LP in liver when injected before irradiation, but enhanced the increase of LP in spleen. None of these radioprotectors including MEA was recognized to inhibit radiation-induced LP in thymus. The in vitro experiments were carried out using mouse liver microsomal suspensions (MS). The MS were prepared from normal (non-irradiated) mice. Each of the 8 radioprotectors was added to MS before or after irradiation and then post-irradiation-incubated at 37 degrees C. All markedly inhibited radiation-induced LP if added before irradiation, but were slightly less effective if added after.

Animals↗

PubMed1992

[Protective effects of the fractions extracted from the callus of Acer nikoense Maxim. on alpha-naphthylisothiocyanate induced liver injury].

It has been reported that the methanol extract from the bark of Acer nikoense MAXIM. (AN) and the fractions separated from this extract showed the protection for liver injuries induced by carbontetrachloride (CCl4) in rat. On the other hand, the evidence manifested that the fractions of the callus of young branches from AN were recognized to have protective effects on the CCl4-induced liver injuries in rat. In this study, the protective activities of the fractions extracted from the callus of AN were investigated on the alpha-naphthylisothiocyanate (ANIT)-induced liver injuries in rat. The protectively active principles on the ANIT-induced liver injuries were found in the ether soluble fraction. The components of the protective effect were purified by repeated silica gel chromatographies. One of the protective substances in this fraction was identified to be beta-sitosterol. The protective fractions on the ANIT-induced liver injuries showed the protective effects on ANIT-induced cholestasis, but did not show cholagogic effects.

1-Naphthylisothiocyanate↗

PubMed1992

[Effects of various methanol extracts of crude drugs on experimental subacute and chronic hepatic injury].

The effects of 5 crude drugs (Myricae Cortex, Polygoni Avicularis Herba, Hyperici Erecti Herba, Forsythiae Fructus, Desmodii Herba) on subacute and chronic hepatic injuries induced by carbon tetrachloride (CCl4) or alpha-naphthylisothiocyanate (ANIT) were investigated in rats. All of these crude drugs suppressed significantly the increase of several biochemical parameters with CCl4-injection twice per week for 4 weeks. Polygoni Avicularis Herba and Desmodii Herba among 5 crude drugs also protected the subacute hepatic injury induced by ANIT-injection for 4 weeks. In addition, the therapeutic effect of Desmodii Herba on the chronic hepatic injury induced by CCl4-injection for 9 weeks was recognized. Desmodii Herba has protective effects on the acute and subacute hepatic injuries induced by CCl4 or ANIT and an improving effect on the chronic injury induced by CCl4. Though the increase of hydroxylproline content in the liver began 4 weeks after the CCl4 or ANIT treatment, every crude drug had no significant effect against the liver fibrosis in these study.

1-Naphthylisothiocyanate↗