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Biomedical subjects

M Tashiro

Publications and source records attributed to M Tashiro.

At least 109 records · Page 6Linked to original sources
PubMed1996

The effects of 5-hydroxydopamine on salivary flow rates and protein secretion by the submandibular and parotid glands of rats.

The secretory effects of 5-hydroxydopamine (5-OHDA) were tested in Nembutal-anaesthetized adult male Sprague-Dawley rats injected I.V. over a wide range of doses, with and without various autonomic antagonists and Ca2+ channel blockers. Polyacrylamide disc gel (15%) and iso-electric focusing (IEF) electrophoresis by the PhastSystem were used to separate and determine the types of protein in submandibular saliva. Amylase activity of parotid saliva was determined by the blue dextran method. Salivation by the submandibular glands following application of 5-OHDA was completely abolished by both prazosin and propranolol, whereas salivation by the parotid glands was completely abolished by propranolol alone. Following application of 5-OHDA, there was a dose-related increase in flow rates and total output of protein, but not in the protein concentration and amylase activity, from both salivary glands. The effect of 5-OHDA on submandibular saliva was significantly reduced by alpha-adrenoceptor blockers, but not by beta-adrenoceptor and cholinergic blockers, nor by any Ca2+ channel blocker. The effect of 5-OHDA on the parotid gland was not significantly altered by atropine and phentolamine. However, after pretreatment with reserpine, a 95% reduction was observed in the salivation from the submandibular gland. This implies that 5-OHDA is mostly acting indirectly via release of noradrenaline. The proteins in submandibular saliva following treatment with 5-OHDA alone or 5-OHDA in combination with beta-adrenoceptor blockers were mainly of the alpha-type, whereas after treatment with 5-OHDA in combination with alpha-adrenoceptor blockers they were of the beta-type. The alpha-type was found in saliva after treatment with each of three Ca2+ channel blockers.

Adrenergic alpha-Antagonists↗
PubMed1996

[Laboratory virological diagnosis of imported dengue cases].

Suspected dengue cases in Japan during the period of 1985-1995, 173 cases with unknown febrile illness entering or returning from mostly southeast Asia, were tested by serology and RT-PCR gene amplification. Seventy seven cases were confirmed by a significant rise of dengue 2 (Den 2) HI antibody in paired sera or by detection of HI antibody titer higher than 1:320 in single serum. The other 3 cases with antibody levels not higher than 1:80 in paired sera and 12 cases with an antibody 1:160 in single sera were positively suspected of dengue infection but were not confirmed. Countries of origin of confirmed cases were Thailand (39 cases), Philippinse (15), India (13), and Indonesia (9). Sera of dengue cases showed high degrees of cross reactivity of Japanese encephalitis virus (JEV) in HI test but not in IgM capture ELISA. Sera of confirmed JEV-infected cases, however, showed practically no cross reactivity to Den 1 4 in HI test, suggesting unilateral cross reactivity of HI antibody. RT-PCR detected the Den 1 genome in sera of 3 cases obtained within 3 days after onset and the Den 2 genome in serum of case 4 days after onset. Although the number is limited, 92 (53%) out of 173 cases of febrile illness of unknown etiology entering Japan from tropical countries were either confirmed or positively suspected to be dengue fever. Considering possibilities of under reporting, importations of tropical viral infections should be bigger in number and will necessitate our intensified alertness.

Asia, Southeastern↗
PubMed1996

Involvement of the mutated M protein in altered budding polarity of a pantropic mutant, F1-R, of Sendai virus.

Wild-type Sendai virus buds at the apical plasma membrane domain of polarized epithelial MDCK cells, whereas a pantropic mutant, F1-R, buds at both the apical and basolateral domains. In F1-R-infected cells, polarized protein transport and the microtubule network are impaired. It has been suggested that the mutated F and/or M proteins in F1-R are responsible for these changes (M. Tashiro, J. T. Seto, H.-D. Klenk, and R. Rott, J. Virol. 67:5902-5910, 1993). To clarify which gene or mutation(s) was responsible for the microtubule disruption which leads to altered budding of F1-R, MDCK cell lines containing the M gene of either the wild type or F1-R were established. When wild-type M protein was expressed at a level corresponding to that synthesized in virus-infected cells, cellular polarity and the integrity of the microtubules were affected to some extent. On the other hand, expression of the mutated F1-R M protein resulted in the formation of giant cells about 40 times larger than normal MDCK cells. Under these conditions, the effects on the microtubule network were enhanced. The microtubules were disrupted and polarized protein transport was impaired as indicated by the nonpolarized secretion of gp80, a host cell glycoprotein normally secreted from the apical domain, and bipolar budding of wild-type and F1-R Sendai viruses. The mutated F glycoprotein of F1-R was transported bipolarly in cells expressing the F1-R M protein, whereas it was transported predominantly to the apical domain when expressed alone or in cells coexpressing the wild-type M protein. These findings indicate that the M protein of F1-R is involved in the disruption of the microtubular network, leading to impairment of cellular polarity, bipolar transport of the F glycoprotein, and bipolar budding of the virus.

Animals↗
PubMed1996

A case of nephrotic syndrome developing during postoperative gamma interferon therapy for renal cell carcinoma.

A 70-year-old man developed minimal-change nephrotic syndrome and acute interstitial nephritis while undergoing gamma interferon therapy following right nephrectomy for renal cell carcinoma. It appears that gamma interferon as well as renal cell carcinoma may have played a role as etiologic factors in this nephropathy. We report this extremely rare case of renal cell carcinoma complicated by minimal-change nephrotic syndrome and acute interstitial nephritis, and present a review of the literature.

Acute Disease↗
PubMed1996

Changes in activity, antigenicity, and molecular size of rice bran trypsin inhibitor by in vitro digestion.

Rice bran trypsin inhibitor (RBTI) was digested by pepsin alone or by pepsin and pancreatin with or without bovine serum albumin (BSA) to clarify the changes in trypsin inhibitory activity, apparent antigenicity, and molecular size of RBTI. In vitro pepsin digestion of RBTI in the absence of BSA caused the gradual loss of the trypsin inhibitory activity and antigenicity. This was mostly due to a progressive degradation of the native 14.5-kDa RBTI molecule to small molecular mass products. The presence of BSA in the digestion mixture prevented the RBTI degradation and was accompanied with a considerable protection of the activity and antigenicity. Similar results were also given by in vitro pepsin-pancreatin digestion. These findings suggest that RBTI may be present in its active form in the gastrointestinal tract when fed to animals, especially with a dietary protein.

Chromatography, High Pressure Liquid↗
PubMed1995

Activation and interaction with protein kinase C of a cytoplasmic tyrosine kinase, Itk/Tsk/Emt, on Fc epsilon RI cross-linking on mast cells.

Cross-linking of the high-affinity IgE receptor (Fc epsilon RI) on mast cells induces rapid phosphorylation on serine, threonine, and tyrosine residues and increases the enzymatic activity, of a Tec subfamily tyrosine kinase, Itk/Tsk/Emt (Emt). The pleckstrin homology domain of Emt at its amino-terminal interacts directly with multiple isoforms of protein kinase C (PKC) in vitro. In addition, a portion of Emt is physically associated with multiple isoforms of PKC in intact mast cells. PKC phosphorylates a bacterial fusion protein containing the pleckstrin homology domain of Emt in vitro. Coexpression of Emt in COS-7 cells with Ca(2+)-dependent PKC isoforms (alpha, beta I, or beta II) induces an enhancement in tyrosine phosphorylation of Emt. In vivo inhibition of PKC expression or activity attenuates tyrosine phosphorylation and enzymatic activity of Emt induced upon Fc epsilon RI cross-linking. These data collectively suggest that PKC phosphorylates Emt and activates its autophosphorylating activity. Alternatively, PKC could activate another tyrosine kinase that phosphorylates Emt, or PKC-mediated phosphorylation of Emt may render it a target for another tyrosine kinase. In any case, PKC appears to play a major role in the activation of Emt induced upon Fc epsilon RI cross-linking.

Animals↗
PubMed1995

Cloning and expression of the gene of hemocytin, an insect humoral lectin which is homologous with the mammalian von Willebrand factor.

Invertebrate lectins play an important role in a non-specific self-defense mechanism, as invertebrates do not synthesize specific antibodies. We report the cloning of several overlapping cDNAs encoding the entire silkworm (Bombyx mori) lectin, which we propose to call hemocytin. The sequence (10477 bp) encoded 3133 amino acids. The characteristics features of the carbohydrate-recognition domain of C-type animal lectin were revealed at C-terminal sequence of hemocytin. When cDNA encoding this region was introduced into baculovirus vector, hemagglutinating activities were detected in the culture fluid of a recombinant virus-infected cells. These activities were inhibited by D-mannose, N-acetyl-D-galactosamine, and D-maltose which are haptenic saccharides of authentic hemocytin. Analysis of dot and Northern blot hybridization revealed that hemocytin gene was transcribed in hemocytes of the silkworm at larval-pupal metamorphosis and/or after the injection of Escherichia coli and lipopolysaccharide. After silkworm larvae were injected with C-terminal portion of hemocytin, aggregation of hemocytes was observed in the hemolymph. Hemocytin has significant homology with mammalian von Willebrand factor which involves in platelet adhesion to subendothelium. Also, hemocytin has a homologous region with coagulation factor V and VIII. These results suggest that hemocytin molecule is an adhesive protein and relates to hemostasis or encapsulation of foreign substances for self-defense.

Amino Acid Sequence↗
PubMed1995

Classification of amino acid spin systems using PFG HCC(CO)NH-TOCSY with constant-time aliphatic 13C frequency labeling.

We have developed a useful strategy for identifying amino acid spin systems and side-chain carbon resonance assignments in small 15N-, 13C-enriched proteins. Multidimensional constant-time pulsed field gradient (PFG) HCC(CO)NH-TOCSY experiments provide side-chain resonance frequency information and establish connectivities between sequential amino acid spin systems. In PFG HCC(CO)NH-TOCSY experiments recorded with a properly tuned constant-time period for frequency labeling of aliphatic 13C resonances, phases of cross peaks provide information that is useful for identifying spin system types. When combined with 13C chemical shift information, these patterns allow identification of the following spin system types: Gly, Ala, Thr, Val, Leu, Ile, Lys, Arg, Pro, long-type (i.e., Gln, Glu and Met), Ser, and AMX-type (i.e., Asp, Asn, Cys, His, Phe, Trp and Tyr).

Amino Acid Sequence↗
PubMed1995

Structures of bacterial immunoglobulin-binding domains and their complexes with immunoglobulins.

Three-dimensional structures are now available for several immunoglobulin binding domains from bacterial proteins A, G, and L. X-ray diffraction and NMR experiments on complexes of these domains with portions of immunoglobulins have revealed common structural themes used in these interactions. These data expand our understanding of structure/function relationships in these molecular recognition processes and provide the basis for rational design of artificial immunoglobulin-binding molecules.

Amino Acid Sequence↗
PubMed1995

Influenza viruses, cell enzymes, and pathogenicity.

Proteolytic cleavage of the influenza virus hemagglutinin glycoprotein (HA) by cellular proteases is a prerequisite for virus infectivity, spread of the virus in the infected organism, tissue tropism, and viral pathogenicity. Production of infectious virus depends upon the structure at the HA cleavage site as well as the substrate specificity and the distribution of appropriate enzymes. Differences exist in the specificities of the endoproteases that recognize the different sequence motifs at the cleavage site. With avian influenza viruses that cause lethal systemic infections, the cleavage site consists of multibasic amino acids. Furin, which activates this type of HA, is a member of the subtilisin family and represents the prototype of ubiquitously occurring membrane-bound proteases. On the other hand, serine proteases secreted from a restricted number of cell types and some bacterial enzymes recognize a monobasic cleavage signal at HA of the mammalian and the apathogenic avian influenza viruses. The limited occurrence of these proteases results in only localized infection. Implementation of these defined conditions for virus activation may represent a novel type of disease control.

Furin↗
PubMed1995

Erythema multiforme associated with superficial fungal disease.

An extremely rare case of erythema multiforme associated with dermatophytosis by Trichophyton rubrum infection was reported in a 19-year-old woman. She had a reddish plaque resembling annular ringworm on her left arm. Treatment with an antifungal cream (clotrimazole) on the infected site cleared the condition in three weeks. Spontaneous regression of erythema multiforme in different parts of the body was recognized when the ringworm infection resolved. In recent years, only two cases have been reported in the English literature.

Adult↗
PubMed1995

[Uterine cervical cancer: usefulness of MR imaging after the initial radiation therapy].

To evaluate the usefulness of magnetic resonance imaging (MRI) in diagnosing residual or recurrent tumors of cervical cancer after radiation therapy, we investigated the time difference between MRI and gynecologic findings in the diagnosis of residual or recurrent tumor in 12 patients with invasive cervical cancer. We defined a positive finding for residual or recurrent tumor as an uterine cervical mass isointense to muscle on T1-weighted images and hyperintense on T2-weighted images, and when a positive biopsy specimen was obtained. Two patients were diagnosed as having a residual or recurrent tumor by MRI. Positivity was demonstrated four and seven months later, respectively. MRI was more useful in the earlier diagnosis of residual or recurrent tumor of cervical cancer after radiation therapy than uterine biopsy. There was one patient whose differentiation from residual tumor or radiation-induced necrosis or inflammation on MRI was difficult. MRI and gynecologic check-up at a regular interval after radiation therapy was needed to distinguish them. One patient was diagnosed as having a recurrent tumor by gynecologic finding three month earlier than by MRI. Follow-up MRI examinations at a regular interval in addition to gynecologic examination is necessary for the early detection of recurrent cervical cancer after radiation therapy.

Adult↗
PubMed1994

Normalization of hair growth in sparse fur-abnormal skin and hair (SPF-ASH) mice by introduction of the rat ornithine transcarbamylase (OTC) gene.

The sparse fur-abnormal skin and hair (SPF-ASH) mouse is a model for the human X-linked hereditary disease, ornithine transcarbamylase (OTC) deficiency. This condition is characterized by abnormal skin and delayed hair growth, hyperammonemia, orotic aciduria and low levels of serum citrulline and arginine. Murakami et al. [1] established a line of transgenic mice, by introducing the recombinant rat OTC (rOTC) gene into fertilized C57BL mouse eggs. We introduced the rOTC gene into SPF-ASH mice by mating SPF-ASH heterozygotes and transgenic mice, which carried this gene. The hemizygous SPF-ASH mice bearing the rOTC gene showed normal hair growth without sparse fur, normal urinary orotic acid excretion and normal serum citrulline and arginine levels. These mice showed OTC activities 2 and 6 times higher in the liver and small intestine, respectively, than the SPF-ASH mice but about 12% and 27% those of the controls [2].

Animals↗
PubMed1994

Immunohistochemical study of c-erbB-2 oncoprotein expression in extramammary Paget's disease.

Sections of formalin-fixed, paraffin-embedded tumor tissue from 20 patients with noninvasive extramammary Paget's disease and 2 patients with invasive extramammary Paget's disease were stained immunohistochemically by means of anti-c-erbB-2 product monoclonal antibody. Membrane staining of intraepidermal tumor cells was found in only 3 of 20 cases of noninvasive extramammary Paget's disease. In the 2 invasive cases, tumor cells of invasive lesions and metastases were positive while intraepidermal tumor cells were negative.

Aged↗
PubMed1994

Sendai virus infection changes the subcellular localization of tryptase Clara in rat bronchiolar epithelial cells.

Tryptase Clara activates the infectivity of Sendai and influenza viruses proteolytically. In this study, we investigated changes in the subcellular localization of tryptase Clara in rat bronchioles with progression of Sendai virus infection. Tryptase Clara and Sendai virus F2 antigen were localized by light and electron immunohistochemical studies. In the uninfected rat lung, tryptase Clara was specifically localized in the secretory granules of respiratory bronchiolar epithelial nonciliated cells, but not in bronchiolar ciliated, or alveolar cells. In the initial stage of Sendai virus infection with slight pathological changes, however, anti-tryptase Clara was highly reactive in luminal peripheral membranes of both nonciliated and ciliated epithelial cells of the bronchioles together with some Sendai virus envelope glycoprotein, F2 antigen. In the progressed stage, tryptase Clara was hard to detect, with heavy accumulation of F2 antigen in the epithelial cells. These immunohistochemical results support our previous findings that in the bronchial lavage fluid tryptase Clara is significantly increased both in amount and activity after viral infection. These results suggest that Sendai virus stimulates the secretion of tryptase Clara from nonciliated bronchiolar epithelial cells to the airway lumen. Accumulation of tryptase Clara on the luminal surface of the bronchiolar epithelial cells and/or in the airway lumen may produce favourable conditions for proteolytic viral activation and multiplication.

Animals↗
PubMed1994

Immunostaining of dystrophin and utrophin in skeletal muscle of dystrophinopathies.

Immunostaining of biopsied skeletal muscle of 4 Duchenne (DMD), 12 Becker muscular dystrophy (BMD) and 3 DMD carriers' was performed using monoclonal antibodies against dystrophin and utrophin. In DMD, dystrophin-negative staining was observed except for revertant fibers which showed different stain patterns for each antibody. In 7 BMDs, there was faint/patchy stain in cases of deletion between exons 45-52, while in one case there was deletion between exons 12-17 and no stain was noted relevant to the deletion site. Moreover, in 2 cases of undetectable deletion, antibodies which recognize a terminal portion of the C-terminal domain revealed the absent stain. In DMD, the utrophin-positive fibers corresponded to dystrophin-negative fibers. In BMD, this relationship did not necessarily occur in each fiber. In DMD carriers, a cluster of dystrophin-negative fibers which was positive for utrophin were prominent. In dystrophinopathy, the immunostaining of dystrophin and utrophin is useful, in combination with dystrophin gene analysis to make a definite diagnosis.

Adolescent↗
PubMed1994

Inhibitory specificity against various trypsins and stability of ovomucoid from Japanese quail egg white.

The inhibitory specificity and stability of ovomucoid from Japanese quail egg white (OMJPQ) were examined to understand its nutritional significance. OMJPQ showed strong inhibitory activities toward trypsins from various origins including human, and the trypsin inhibitions occurred at molar ratios of enzyme to inhibitor between 1/1 and 2/1. On the other hand, an equimolar mixture of the second and third domains of OMJPQ inhibited bovine trypsin more strongly than the corresponding native OMJPQ did. This distinction was partly explained by the presence of steric hindrance on the formation of a 2:1 trypsin-OMJPQ complex. OMJPQ retained about 100% of its original activity over a pH range from 1 to 12 after a 24-h incubation at 37 degrees C. The inhibitor was most thermostable between pH 2 and 5, where more than 70% of its original activity was maintained after a 1-h incubation at 100 degrees C and about 25% of the activity even after a 30-min incubation at 121 degrees C. OMJPQ was also considerably resistant to pepsin attack. Pepsin digestion of the protein resulted in only about 40% loss of the original trypsin-inhibitory activity even after a 24-h digestion. Furthermore, the addition of bovine serum albumin to the digestion mixture brought about rapid elevation in the trypsin-inhibitory activity during an initial 30-min digestion. SDS-PAGE and immunoblot suggested that this was due to the liberation of active inhibitory domains from the native molecule by inter-domain proteolysis.

Animals↗