Biomedical subjects

M Miyoshi

Publications and source records attributed to M Miyoshi.

At least 37 records · Page 2Linked to original sources

PubMed1999

Characteristics of nitrogen metabolism in rats with thioacetamide-induced liver cirrhosis.

Female Sprague-Dawley rats were given 0.03% thioacetamide (TAA) in their drinking water daily for 4 or 12 weeks, and were then given normal water for 4 weeks after the end of a 12-week TAA treatment to investigate amino acid metabolism. In the malnourished precirrhotic stage (stage 1) and the malnourished cirrhotic stage (stage 2), the aromatic amino acids (AAA), Glu, Asp, Orn, Arg and Cit increased, and the branched-chain amino acids (BCAA) decreased slightly. Because these changes normalized in the well-nourished cirrhotic stage (stage 3), they might have resulted from impairment of hepatocytes and malnutrition. The net uptake of BCAA into the liver increased in stage 2, but the AAA uptake did not exceed that in normal controls. Portal venous plasma AAA increased to the same level as arterial plasma AAA. These results suggest that the decrease in BCAA was partially due to liver uptake and that the increase in AAA was induced by reduction of liver uptake and overproduction in extrahepatic tissues. The liver contents of BCAA and AAA were unchanged in all stages, so were fully utilized in the impaired liver. The increases in Glu, Asp, Orn and Cit might have resulted from overproduction in the liver, because these contents of the liver increased in stage 2. In conclusion, the changes in amino acid metabolism in rats with cirrhosis induced by TAA closely resemble those seen in human liver cirrhosis.

Amino Acids↗

PubMed1999

Stress fiber networks in sinus endothelial cells in the rat spleen.

The wall of the splenic sinus is well known to be a critical site in the control of the blood-cell passage through the splenic cord. However, there is little information on what mechanism controls the blood-cell passage between the sinus endothelial cells adhered with intercellular junctions. Stress fibers of sinus endothelial cells in the rat spleen were examined by transmission electron microscopy and immunofluorescence microscopy. After extraction with saponin, the stress fibers were found to be conspicuously electron-dense in the basal portion of the cells and demonstrated two characteristic types and the mixed type of these. One type of the stress fibers was corrugated and formed thick, electron-dense bundles, and the other type had straight bundles with electron-dense areas at intervals. Statistically, the lengths of two types of stress fibers are significantly different. Although most of the stress fibers were segmented by the ring fibers, some of them ran successively beyond the attachment site of the ring fibers and thus stretched longitudinally and tangentially in the basal part of the cell to form a widespread network. The peripheries of the networks were attached to the basal plasma membrane at the ring fibers and the lateral membranes at the focal adhesions and the cell-cell adherens junction, respectively. Phosphotyrosine is localized in the basal part and at the intercellular adhesion site of the endothelial cells. Two types of stress fibers were organized in the sinus endothelial cells, and they form a widespread network. The possibility might be considered that stress fibers play important roles in the signal transduction and the regulation of cellular attachment and detachment.

Animals↗

PubMed1999

Tubular invaginations with caveolae and coated pits in the sinus endothelial cells of the rat spleen.

The fine structure of plasmalemmal tubular invaginations with caveolae and coated pits in the sinus endothelial cells of the rat spleen has been demonstrated by scanning and transmission electron microscopy. In addition, the three-dimensional structure of the tubular invagination has been revealed by computer-aided reconstruction. The tubular invaginations of the plasma membrane plunged into the cytoplasm everywhere from the apical, lateral, and basal surfaces of the plasma membrane. The invaginations were tubular and branched away, and their plasma membranes were reinvaginated to form numerous caveolae and occasional coated pits. Numerous caveolae were found in clusters that looked similar to a bunch of grapes and the coated pits were present at the base of the clusters. The caveolae and coated pits derived from the tubular invaginations were almost ultrastructurally identical to those derived from the surface plasma membrane. From examination of the fractured surfaces of the endothelial cells treated with the aldehyde prefix osmium-dimethyl sulfoxide-osmium method and of ultrathin sections of those infiltrated by lanthanum nitrate, the tubular invaginations were found to not penetrate any endothelial cells. A computer-aided reconstruction revealed that the caveolae derived from the tubular invaginations were in close apposition to the surface-connected canaliculi. The reaction product of Concanavalin A conjugated to horseradish peroxidase was present on the outer leaflet of the membranes of the coated pits and coated vesicles and also in the contents of the endosomes, but it was absent from any caveolae. Based on our observations, the functional significance of the tubular invaginations in sinus endothelial cells is discussed.

Animals↗

PubMed1999

The surface-connected canalicular system in the sinus endothelial cells of rat spleen.

The existence of a surface-connected canalicular system in the splenic sinus endothelial cells of the rat has been demonstrated by transmission electron microscopy with lanthanum nitrate acting as a tracer for the extracellular space. In addition, the three-dimensional arrangement of the canaliculi has been revealed by computer-aided reconstruction. The surface-connected canalicular system of the sinus endothelial cells consists of slender canaliculi that are branched, anastomosed, and that show continuity with the plasma membrane. They twist in and out among the organelles and are often found in close apposition to the spherical invaginations of the plasma membrane and run alongside them. Canaliculi which are not infiltrated by lanthanum nitrate take the form of electron-lucent tubules and are accompanied by numerous spherical invaginations of the plasma membrane. From a computer-aided reconstruction, the canaliculi, which invaginate from various sites of the plasma membrane, have been found to be continuous with each other and to penetrate to the surface of the sinus endothelial cell; they also branch and anastomose to form a complex network in the cytoplasm. Although the surface-connected canalicular system in blood platelets and thrombocytes is believed to function as the main route for the discharge of granules and the uptake of foreign materials and also to take part in the storage and transport of calcium, it is unclear at present whether the network of the surface-connected canalicular system in splenic sinus endothelial cells has any physiological significance.

Animals↗

PubMed1999

Structure of the immediate early gene of canine herpesvirus.

The nucleotide sequence of the immediate early (IE) gene of canine herpesvirus was determined. This gene was located in the inverted repeat regions, encoding a polypeptide of 1,383 amino acids. The predicted amino acid sequence was most closely related to that of the feline herpesvirus 1 IE protein among those of other alphaherpesviruses. DNA binding and transcriptional activation domains were found in the IE protein. A spliced region of the IE gene transcript was determined in its 5' non-coding region.

Amino Acid Sequence↗

PubMed1999

Tight junction of sinus endothelial cells of the rat spleen.

The fine structure of the tight junctions between sinus endothelial cells of the rat spleen and the permeability of such sinus endothelial cells were examined by transmission electron microscopy, using freeze-fracture, triton extraction, and lanthanum-tracer techniques. In freeze-fracture replicas, the segmented strands and grooves of the tight junctions were frequently observed on the basolateral surfaces of the sinus endothelial cells irrespective of the location of the ring fiber. There were one or two wavy-strands or grooves which were, for the most part, oriented parallel to the long cell axis thus forming networks at places. In addition, some strands or grooves were discontinuous while some networks of the junctional strands were not closed. These strands also occasionally lacked intramembranous particles in the tight junctions. The junctional strands run apicobasically at certain sites. In the vertical sections of the sinus endothelial cells treated with lanthanum nitrate, although no tight junctions were observed wherever the endothelial cells were apposed, most of them were situated on the basal part of the lateral surfaces of the adjacent endothelial cells. Several fusions of the junctional membranes were observed in a vertical section of the lateral surfaces of the adjacent endothelial cells. The intercellular spaces of the adjacent endothelial cells except for the fusion of the junctional membranes, were electron dense and the infiltration of lanthanum nitrate was found not to be interrupted by these tight junctions. Based on these observations, the molecular 'fence' and paracellular 'gate' functions of the tight junctions in the sinus endothelial cells are discussed.

Adult↗

PubMed1999

Detection of canine herpesvirus DNA in the ganglionic neurons and the lymph node lymphocytes of latently infected dogs.

To determine the site of latent infection of canine herpesvirus (CHV), tissues from dogs convalescent from acute infection with CHV were examined for the presence of viral genome DNA by the nested polymerase chain reaction. CHV DNA was detected in the trigeminal ganglia and the retropharyngeal lymph nodes. In situ hybridization study of the tissues revealed that CHV genome persisted in the nuclei of ganglionic neurons and lymphocytes.

Animals↗

PubMed1999

[Clinical evaluation of urinary leukotriene E4 levels in children with atopic dermatitis].

To evaluate the significance of peptide leukotrienes in children with atopic dermatitis, we measured urinary LTE4 levels which are thought to reflect in vivo production of peptide LTs. Urine was collected in the early morning. There was no significant difference in urinary LTE4 levels among atopic children with different severities. On the other hand, urinary LTE4 levels were significantly elevated in the patients who had severe nocturnal itches compared with the patients who had mild nocturnal itches and normal controls. These results suggested that increased production of peptide LTs may be relevant to nocturnal itch of atopic dermatitis.

Adolescent↗

PubMed1998

Glutathione depletion inhibits oxidant-induced activation of nuclear factor-kappa B, AP-1, and c-Jun/ATF-2 in cultured guinea-pig gastric epithelial cells.

The aim of this study was to reveal the role of intracellular glutathione in the oxidative stress responses of gastric epithelial cells. Metabolic radiolabeling with L-[35S]methionine and analysis of synthesized proteins by gel electrophoresis and fluorography showed that upon exposure to hydrogen peroxide (H2O2) or diamide, primary cultures of guinea-pig gastric epithelial cells rapidly induced several undefined proteins, as well as heat shock proteins. When intracellular glutathione was depleted to less than 10% of the control value by treatment with buthionine-[S,R]-sulfoximine, these inductions were completely inhibited. Gel mobility shift assay demonstrated that H2O2 and diamide rapidly activated nuclear factor-kappa B (NF-kappaB), and diamide activated activator protein (AP)-1, and c-Jun/activating transcription factor (ATF)-2, suggesting that the response may be coupled to these reduction-oxidation (redox)-sensitive transcription factors, as well as heat shock transcription factor 1. The activations of NF-kappaB, AP-1, and c-Jun/ATF-2 by the oxidants did not occur in glutathione-depleted cells. Northern blot analysis showed that glutathione depletion markedly or completely suppressed the diamide-induced expression of c-fos and c-jun mRNAs. These results suggest that intracellular glutathione redox may participate in the initiation of oxidative stress responses; thereby, it plays an important role in gastric mucosal defense.

Activating Transcription Factor 2↗

PubMed1998

Chemoreceptive epithelioid cells in the chicken aorta. An electron microscopical study.

Aggregations of granulated epithelioid cells exist in the chicken aorta. In the present study, the locational characteristics of the epithelioid cells were investigated via an electron microscopic approach. Epithelioid cells were found mainly in two regions; the tunica interna just below the endothelial cell layers, and the intermediate region of the tunica media. In the former, the epithelioid cells were in contact with endothelial cells and sometimes directly exposed to the aortic lumen. No contact between the epithelioid cells and the nerve endings was observed in this region. On the other hand, in the intermediate region of the tunica media, five or more epithelioid cells were aggregated, and the synaptic structures were occasionally observed. Additionally, the epithelioid cells in this region was observed to closely contact smooth muscle cells. In an experiment using horseradish peroxidase injection, reactions were detected in the intercellular spaces between the epithelioid cells and endothelial cells. These results suggest that the epithelioid cells localized in the subendothelial region receive information from the aortic lumen, whereas their aggregations in the tunica media are controlled by the nervous system.

Animals↗

PubMed1998

Life-threatening hemorrhage in a patient with gastric cancer and acquired hemophilia.

We report a case of a patient with life-threatening hemorrhage caused by the presence of acquired factor VIII inhibitors after gastrectomy for signet-ring cell carcinoma of the stomach. Acquired factor VIII inhibitors should be taken into consideration as a cause of acquired bleeding tendency among patients with gastrointestinal malignancies especially when the coagulation tests are unusual.

Aged↗

PubMed1998

[Evaluation of theophylline in children hospitalized with asthma attack].

The purpose of this study is to determine whether theophylline provides clinical benefits in the hospitalized children with asthma attack. Aminophylline was intravenously given to the 50 patients (Group A) who were admitted 1994. A small dose of aminophylline compared to that of Group A was given to the 44 patients (Group B1) who were admitted 1998. On the other hand, aminophylline was not given to the 12 patients (Group B2) who were admitted 1998. However, there were no differences among those groups in the duration of admission, in the total dose of intravenously given methylprednisolone, and in the improvement of clinical score of asthma. These results suggested that there was no clinical benefit in using theophylline for treatment to hospitalized children with asthma attack combined high fever.

Aminophylline↗

PubMed1998

Implications of heat shock/stress proteins for medicine and disease.

Heat shock/stress proteins (HSPs) are crucial for maintenance of cellular homeostasis during normal cell growth and for survival during and after various cellular stresses. The HSP70 family functions as molecular chaperones and reduces stress-induced denaturation and aggregation of intracellular proteins. In addition to the chaperoning activities, HSP70 has been suggested to exert its protective action by protecting mitochondria and by interfering with the stress-induced apoptotic program. The biochemical and functional properties of HSPs observed in cultured cells may be relevant to organs and tissues in whole animals. The activation of the hypothalamic-pituitary-adrenal axis and the sympathetic nerve system elicits the stress response in selected peripheral tissues; the HSP70 expression in the vasculature and stomach increases resistance against hemodynamic stress and stress-induced mucosal damage, respectively. Gastric mucosa pretreated with mild irritants acquires a tolerance against subsequent mucosal-damaging insults. This phenomenon is known as "adaptive cytoprotection". Transient ischemia also induces ischemic tolerance in the brain and heart, which is called "ischemic preconditioning". The heat shock response is believed to contribute to the acquisition of the tolerance. The therapeutic applications of chaperone inducers that induce HSPs without any toxic effect are also introduced.

Animals↗

PubMed1998

[The comparative study of LUMIWARD immunoassay system and CAP RAST system for determination of specific IgE antibody against mite in infantile atopic dermatitis].

We determined the levels of specific IgE antibody against mite in 91 infants with atopic dermatitis by CAP RAST system and LUMIWARD immunoassay system, and observed them for about two years. The correlation between CAP RAST and LUMIWARD was weak. The cut off point was set up at 0.06 IU/ml, most of the patients who had asthma attack or whose atopic dermatitis were poorly controlled during two years judged to be positive. In conclusion, the determination of low levels of specific IgE antibody against mite in infants with atopic dermatitis was reliable to prediction of allergy.

Animals↗

PubMed1997

Junctions between the sinus endothelial cells of rat spleen.

Junctions between the sinus endothelial cells of rat spleen were examined by electron microscopy, using both freeze-fracture and detergent-extraction techniques. Adherens and tight junctions were observed. Adherens junctions were the predominant junctional structures between endothelial cells and were located on basolateral and lateral surfaces. At the basolateral adherens junctions, actin filaments were associated with the junctional membranes and were continuous with the actin filaments in stress fibers. Cross-bridges were present in the interspaces of the adherens junctions and spacing of the bridges was fairly regular. A form of tight junction, the macula occludens, was also observed between the endothelial cells, but it was not observed at every cellular apposition. Electron-dense material, adjoining the cytoplasmic surfaces of membranes in the tight junctions, separated the junctional membranes from masses of thin filaments. At basolateral tight junctions, the actin filaments were continuous with those in the stress fibers. Based on these observations, the two intercellular junctions were considered to play important roles in sinus functions.

Animals↗

PubMed1997

Sequence and phylogenetic analyses of highly virulent infectious bursal disease virus.

The nucleotide sequences of the genome segments A and B encoding the precursor polyprotein (NH2-VP2-VP4-VP3-COOH) and VP1 were determined for a highly virulent strain of infectious bursal disease virus (IBDV). The precursor polyprotein and VP1 coding regions of highly virulent OKYM strain consisted of 3039 nucleotides (1012 deduced amino acids) and 2640 nucleotides (879 deduced amino acids), respectively. Comparison of the deduced amino acid sequences of the highly virulent IBDV (HV-IBDV) with other serotype 1 and 2 sequences revealed 17 amino acid residues which were conserved only in the HV-IBDV. Among the 17 unique amino acid differences, 8 were in VP1, 4 were in VP2, 3 were in VP3 and 2 were in VP4. Although it is impossible to predict the effect of the unique amino acid residues without detailed knowledge of the three-dimensional structure and function of the proteins, they could affect the virulence of HV-IBDV. Alignment of the nucleic acid sequences of precursor polyprotein, VP1, VP2, VP3 and VP4 coding regions followed by distance analysis allowed the generation of phylogenetic trees. The same tree topology was obtained for the nucleotide sequence of precursor polyprotein, VP2, VP3 and VP4. On the other hand, the tree topology of VP1 was quite different from that obtained for the nucleotide sequence of precursor polyprotein, VP2, VP3 and VP4. These findings indicate that not a genetic recombination but a genetic reassortment may play an important role in the emergence of HV-IBDV.

Amino Acid Sequence↗

PubMed1997

Effect of retained placenta on subsequent bacteriological and cytological intrauterine environment and reproduction in Holstein dairy cows.

To determine the effect of retained placenta on the characteristics of the intrauterine environment in dairy cows, bacteriological and cytological tests were performed on intrauterine perfusion fluid. The rate of cows with more than 70% neutrophils or fewer than 40% lymphocytes in inflammatory cells was 48.0% (12/25), while the rate and with more than 50 bacterial colonies/0.1 ml of perfusate was 96.0% (24/25) at 30 d after parturition. Actinomyces pyogenes was isolated from 56.0% (14/25). At 60 d after parturition, however, these values were significantly improved to 20.0% (5/25), 48.0% (12/25) and 12.0% (3/25), respectively. No significant differences in subsequent reproductive performance were observed between cows with and without retained placenta. The results suggest that injury to the intrauterine environment caused by retained placenta is largely healed by 60 d after parturition.

Journal Article↗

PubMed1997

Oxidant-induced activation of nuclear factor-kappa B in cultured guinea pig gastric epithelial cells.

The aim of this study was to reveal oxidant-sensitive components in gastric epithelial cells, which may regulate inflammatory processes in gastric mucosa. Gel mobility shift assay showed that treatment of cultured guinea pig gastric epithelial cells with hydrogen peroxide or diamide produced a KB oligonucleotide-protein complex within 5 min. The binding proteins consisted of a p50/p65 heterodimer, which was identified by immunosupershift, UV cross-linking, and immunoprecipitation analyses. Immunocytochemical study demonstrated that surface epithelial cells and parietal cells expressed p500 and p65 mainly in the cytosol, and the oxidants rapidly initiated the nuclear translocation of the components. The oxidants caused the up-regulation of p105 (a p50 precursor) synthesis and the expression of inducible nitric oxide synthase mRNA. These results suggest that the oxidant-sensitive p50/p65 heterodimer in gastric epithelial cells may play an important role in transcriptional activation of genes involved in inflammatory responses of the stomach.

Animals↗