Search PubMed⌕ Search

Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 433 records · Page 24Linked to original sources
PubMed1994

[Conduction disturbances after coronary artery bypass grafting with retrograde cardioplegia].

We studied forty-six cases, who had undergone coronary artery bypass grafting with retrograde cold blood cardioplegia for myocardial protection, to manifest the frequency and causative factors of postoperative conduction disturbances. We obtained the following conclusions. 1) Postoperative conduction disturbances developed in nineteen cases (41.3%), all of which were right bundle branch blocks, but these were usually transient and were not associated with further complications in the follow-up period. 2) There were no significant differences in many factors, including number of grafts, aortic cross-clamp times, or peak CK-MB between cases with and without postoperative conduction disturbances.

Adult↗
PubMed1994

Tumor necrosis factor-alpha mRNA expression in lipopolysaccharide-stimulated rat kidney. Chronological analysis of localization.

To study the time course of lipopolysaccharide-induced production of tumor necrosis factor-alpha (TNF-alpha) in the kidney, we utilized a highly sensitive non-radioisotopic in situ hybridization with 1-nm gold-conjugated anti-digoxigenin for localization of TNF-alpha mRNA expression after lipopolysaccharide administration. TNF-alpha mRNA expression localized by in situ hybridization showed a peak increment in proximal tubular epithelial cells and glomeruli at 2 hours and returned to almost normal levels at 6 hours. The intensity of the signal was much stronger in proximal tubules than in glomeruli. These findings were confirmed by the demonstration of similar kinetics in the increase of TNF-alpha message, measured by using amplification of the third and fourth exons of TNF-alpha gene by reverse transcription-polymerase chain reaction of microdissected proximal tubular segments and isolated glomeruli. Reverse transcription-polymerase chain reaction of cultured rat mesangial and glomerular epithelial cells demonstrated that mesangial cells, not glomerular epithelial cells, were responsible for the observed glomerular signals.

Animals↗
PubMed1993

Purification and partial characterization of a lysine-specific protease of Porphyromonas gingivalis.

A lysine-specific protease hydrolysing peptide bonds at the carboxyl side of lysine residues in Porphyromonas gingivalis was purified from culture supernatant by a combination of ion-exchange chromatography, gel filtration, and affinity chromatography. The molecular mass was 48 kDa and the pI value was 7.3. The enzyme hydrolysed the peptide bonds at the carboxyl side of lysine residues in synthetic substrates and natural proteins.

Amino Acid Sequence↗
PubMed1993

Inhibition of high-molecular-weight-(1-->3)-beta-D-glucan-dependent activation of a limulus coagulation factor G by laminaran oligosaccharides and curdlan degradation products.

Extensive surveys for the effects of various beta-D-glucans on the coagulation cascade in horseshoe crab amebocyte lysates showed that low-mol-wt-(1-->3)-beta-D-glucans and laminaran oligosaccharides inhibit the activation of a limulus coagulation factor G by high-mol-wt-(1-->3)-beta-D-glucans. The inhibitory properties are exclusively dependent upon their number-average mol wt (Mn) in a range of 342-58,100, which correspond to a degree of polymerization (dp) range of 2-359. The most effective is a laminaran dextrin of Mn 5800 (dp of 35-36), which causes 50% inhibition of factor G activation at a concentration of 3.16 ng/mL. The inhibition of the activation of factor G proportional to the concentration of the inhibitor, and the adsorption of factor G by inhibitory beta-D-glucan-conjugated cellulose suggested a high affinity of the inhibitory saccharides for the activator-recognition site of factor G. Branched (1-->6), (1-->3)-beta-D-glucans, laminarans, mixed linkage (1-->3), (1-->4)-beta-D-glucans, and partially substituted curdlan and laminaran were found to be inhibitory, possibly owing to clusters of consecutive (1-->3)-beta-D-glucopyranosyl residues as intrachain units. The inhibition appears to be related to the inability of the inhibitory (1-->3)-beta-D-glucans to form ordered conformations and to their tendency to take a random-coil structure in aqueous solution.

Animals↗
PubMed1993

Rapid freezing replica studies of membrane specializations in the proximal tubules of mouse kidney.

The membrane specializations of the fresh unfixed kidney cortex of adult and neonatal ICR mice were examined by using rapid freezing replica methods. In proximal tubular cells, numerous apical intracellular tubules exhibited helical patterns on the E face with a pitch of about 12 nm. This regular pattern was often continuous with similar striped indentations on the edge of the vacuoles connecting with the tubules. On the luminal surface (ES) of these vacuoles, membrane surface particles were arranged regularly in striped patterns with a center-to-center spacing of about 12 nm. We could not identify differentiations on the PF or PS of the same membrane systems. Another membrane specialization was a plaque or patch of clear pits in tilted lattice alignments on the P face of the large vacuoles with a center-to-center spacing of about 20 nm. This type of specialization was often observed in the neonatal mice proximal tubular cells. These membrane specializations may indicate the active membrane functions in the proximal tubules and suggest the functional continuity and structural relationship of these apical endocytic membrane systems.

Animals↗
PubMed1993

Differential induction of prostaglandin E2-dependent and -independent immune suppressor cells by tumor-derived GM-CSF and M-CSF.

Both prostaglandin E2 (PGE2)-dependent (indomethacin-sensitive) and PGE2-independent (indomethacin-insensitive) suppressor cell activities that inhibited mitogenic T cell blastogenesis appeared in the bone marrow and spleen of mice on days 20 to 30 following transplantation of NFSA fibrosarcoma molecularly expressing mRNA for both macrophage (M) and granulocyte-macrophage (GM) colony-stimulating factors (CSFs). The present study was done to characterize the two different suppressor cells isolated from NFSA tumor-bearing mice and to verify a role of CSFs in the induction of suppressor cells in vitro. Whereas PGE2-releasing suppressor cells were found in bone marrow and spleen cells isolated from tumor-bearing mice, indomethacin-insensitive suppressor cells in both tissues were localized predominantly in adherent cell fractions. An increase in Mac-1+ and Mac-2+ spleen cell populations with two to three times larger cell volumes was observed, and both showed strong PGE2-releasing capacity and indomethacin-sensitive suppressor cell activity. However, after elimination of Mac-1+ or Mac-2+ cells, bone marrow cells still showed higher PGE2-releasing capacity and indomethacin-sensitive suppressor activity. The in vitro cultures of normal bone marrow and spleen cells with NFSA cell conditioned medium (NFSA-CM) induced heterogeneous mixtures of indomethacin-sensitive and - insensitive suppressor cells like those observed in cultures with the combination of M-CSF and GM-CSF. However, cultures with either GM-CSF or M-CSF resulted in the induction of indomethacin-sensitive suppressor cells by GM-CSF and of indomethacin-insensitive suppressor cells by M-CSF. In addition, NFSA-CM pretreated with anti-GM-CSF antibody induced indomethacin-insensitive suppressor cells in in vitro cultures of bone marrow and spleen cells. These results suggest that two distinctly different suppressor cells developed under hemopoiesis of myelomonocytic lineage cells are regulated differentially by the two macrophage growth factors, M-CSF and GM-CSF.

Animals↗
PubMed1993

The size of regional lymph nodes does not correlate with the presence or absence of metastasis in lymph nodes in rectal cancer.

We evaluated the relationship between the size of regional lymph nodes and the presence of metastasis in them in rectal cancer. Of 1,064 lymph nodes in 46 specimens, 133 (13%) were found to have metastases. A half of the positive nodes and most of the negative ones were less than 5 mm in diameter. Therefore, we must find lymph nodes smaller than 5 mm in diameter for assessment of lymph node metastasis. Although positive nodes were larger than negative ones, there was no significant difference. However, when comparing the size of lymph nodes in relation to their location, the epi- and pararectal lymph nodes larger than 10 mm in diameter were highly suggestive of metastases, but the size of the lymph node was not a reliable indicator of lymph node metastases in other situations.

Humans↗
PubMed1993

The clinical significance of regional variations in histologic differentiation within carcinomas of the colorectum.

The clinical significance of the presence or absence of regional variations in histologic differentiation within a primary colorectal carcinoma was investigated in this study. Regional variations in histologic differentiation were judged to be present when the low power field of a microscope was occupied by cancer tissue cytologically and architecturally different from that of the surrounding area. Regional variations in histologic differentiation were noted in 153 (42%) of 368 primary carcinomas. Carcinomas with regional variations were of an anaplastic histologic type and had a higher incidence of lymph node metastasis and a worse prognosis than those without regional variations. Thus, the histologic diversity within a carcinoma is thought to be important for determining the prognosis of patients with colorectal cancer.

Adenocarcinoma↗
PubMed1993

Immunocytochemistry of types I-IV collagen in human anterior subcapsular cataracts.

Human anterior subcapsular cataracts were examined by immunocytochemistry to investigate which types of collagen constitutes the subcapsular fibrous matrix. Types I, III, and IV collagen were shown to be immunologically positive by both light and electron microscopy. In light microscopy, types I and III collagen were stained diffusely whereas type IV collagen was stained in a streaky pattern in the opacities. The lens capsules were stained with antibody to type IV collagen, although the staining patterns were not homogeneous; the inner layers of the capsules were labeled more strongly than the outer layers. Neither type I nor III collagen was detected in the capsules. In electron microscopy, collagen fibrils were labeled with the antibodies to both type I and type III collagen. The lens capsules and multilamellae of the basement membranes in the opacities were labeled with the antibody to type IV collagen.

Basement Membrane↗
PubMed1993

No evidence for a point mutation at codon 713 and 717 of amyloid precursor protein gene in Japanese schizophrenics.

A point mutation at codon 717 of amyloid precursor protein (APP) gene has been demonstrated to play an important pathogenic role in some cases of familial Alzheimer's disease (FAD). Recently, a single case of chronic schizophrenia with a point mutation at codon 713 of APP gene which sits very close to the mutation in FAD was reported. We screened for these two kinds of mutations in 39 schizophrenic patients using polymerase chain reaction (PCR) and restriction enzyme technique. A mutation of codon 713 creates a MaeIII restriction site and that of codon 717 creates a BclI site. Enzyme digestion with amplified PCR product revealed no restriction site in all subjects. None of our subjects had either of these two kinds of mutations. Our findings support the hypothesis that the case of a mutation at codon 713 of APP gene is a natural non-pathogenic variant and, as well as a mutation at codon 717, has no relation with the genetic predisposition to schizophrenia.

Adult↗
PubMed1993

Effect of etodolac on type-II collagen-induced arthritis in mice.

We tested the effect of etodolac on the development of type-II collagen-induced arthritis in DBA/1J mice. It was administered orally once daily for 35 days after the primary immunization with type-II collagen. Etodolac (10 mg/kg) significantly inhibited the development of signs of arthritis on day 28 to day 35. Indomethacin (1 mg/kg) also significantly inhibited it on day 29 to day 34. Radiographic examination showed that etodolac (10 mg/kg) significantly prevented the development of osteopenia, bone erosion and new bone formation of the joints on day 35, while indomethacin (1 mg/kg) significantly prevented only the development of bone erosion. Histopathological examination showed that both etodolac (10 mg/kg) and indomethacin (1 mg/kg) significantly prevented the development of synovitis, erosion of cartilage of the joints and bone destruction of the limbs on day 35. Etodolac and indomethacin did not affect the serum level of anti-type-II collagen antibodies. These results suggest that etodolac and indomethacin suppress type-II collagen-induced arthritis without affecting humoral immune responses.

Animals↗
PubMed1993

Experimental ileitis in dogs and colitis in rats with trinitrobenzene sulfonic acid--colonoscopic and histopathologic studies.

Using a novel experimental model of chronic enterocolitis described by Morris et al., we observed sequential changes of mucosal lesions endoscopically and performed histopathological studies. Fisher rats were rectally administered 25 mg of trinitrobenzene sulfonic acid (TNBS) dissolved in 0.5 ml of 50% ethanol (ET). The combination treatment of TNBS and ET produced colitis in rats for over 3 weeks. TNBS itself did not induce any lesions. ET alone induced mucosal lesions, but their severity was much smaller than that induced by TNBS/ET. As an animal model much closer to human inflammatory bowel disease, we have newly developed a canine model of chronic ileitis. Adult mongrel dogs were administered 10 ml of 100% ethanol and 1 g of TNBS dissolved in 10 ml of distilled water (i.e., 100 mg/ml solution) through a 4-lumen double balloon tube which was inserted into the ileum. The TNBS/ET-induced ileitis in dogs persisted for 8 weeks. The mucosal lesions induced by TNBS/ET were characterized as annular or longitudinal ulcers accompanied by extensive lymphocyte infiltration and granulomas, which were similar to macro- and microscopic findings observed in human Crohn's disease. Endoscopic examinations were a valuable tool to obtain sequential information on the development of inflammatory changes in each individual animal. Our canine model would provide various advantages for the study of functional impairment in chronic enterocolitis as well as for the detection of potential therapeutic agents in the human counterpart.

Animals↗
PubMed1993

Immunohistochemical localization of group II phospholipase A2 in human pancreatic carcinomas.

The immunohistochemical localization of group II phospholipase A2 (PLA2) in normal fetal and adult human pancreases, 5 chronic pancreatitis, and 30 pancreatic ductal carcinomas was investigated. Furthermore, pancreatic carcinoma cases were correlated with histologic type, tumor size, vascular involvement, lymphatic involvement, perineural invasion, lymph node metastasis, amount of interstitial tissue in the tumor, growth pattern of the tumor, and clinical stage. In the normal pancreases, almost all of acinar cells and a few cells of small and large ducts were immunoreactive in a supranuclear pattern. In chronic pancreatitis, immunoreactivity was retained in several acini, islet cells, and ductal cells, but the staining was diminished in acinal cells of atrophic lobules. A strong immunoreactivity was found in the cells of hyperplastic ducts. In pancreatic ductal carcinomas, the immunoreactivity was observed in 25 cases (83%). Eighteen of 25 (72%) immunoreactive cases showed a cytoplasmic granular or luminal surface pattern, both of which were not observed in the normal pancreas. Among the clinicopathological parameters of pancreatic cancer, the incidence of expression of this enzyme was significantly higher in infiltrative type cancers than in expansive and localized tumors. Furthermore, the expression of group II PLA2 was significantly higher in the tumor with larger amount of interstitial tissue than in that with smaller amounts of interstitial tissue. These results suggest that expression of group II PLA2 in human pancreatic ductal carcinomas is possibly involved in the proliferation of interstitial tissue directly or indirectly through prostaglandin production.

Adult↗
PubMed1993

Effects of transforming growth factor-beta on collagen gene expression and collagen synthesis level in mineralizing cultures of osteoblast-like cell line, MC3T3-E1.

1. High levels of type I collagen mRNA and [3H]proline incorporation into collagenase digestable protein by MC3T3-E1 cells were detected during the first 7 days of culture, after which they declined. 2. Type I collagen gene expression was stimulated by TGF-beta in the early culture stage when the collagen gene expression was fully functioning. 3. However, these stimulatory effects disappeared at the differentiation stages. Although collagen gene expression was stimulated by TGF-beta (2.0 ng/ml) in early culture, collagen synthesis in medium was not. 4. This study shows that collagen synthesis and collagen gene expression were affected by the state of differentiation in MC3T3-E1 cells and that the rate of stimulation by TGF-beta in collagen gene expression decreased over time in culture.

Animals↗
PubMed1993

Characterisation and localisation of a 67 kDa calcium binding protein (p67) isolated from bovine hearts.

OBJECTIVE: A 67 kDa Ca2+ binding protein (p67) from bovine hearts has recently been purified. It bound Ca2+ in vitro and localised at the sarcolemma of both striated and smooth muscle cells. In this study, further biochemical and morphological experiments were carried out to examine whether the p67 is a member of the annexin family of proteins and how the protein is associated with the sarcolemma membrane. METHODS: Phospholipid and biological membrane binding assays were used to determine if p67 has the properties of the annexin family of proteins. Extraction experiments with Triton X-114 and Na2CO3 were carried out to examine potential association of p67 with sarcolemma membrane vesicles isolated from bovine hearts. For characterisation of the protein, actin binding assays and immunoelectron microscopy were performed. RESULTS: The p67 bound to acidic phospholipids and biological membranes in a Ca2+ dependent manner. The protein was exclusively recovered in the aqueous phase after Triton X-114 phase separation and it was released from sarcolemma membranes by Na2CO3 treatment. It bound to membrane cytoskeletons insoluble in Triton X-100 but failed to bind to F actin at physiological free Ca2+ concentrations. Immunoelectron microscopy showed that p67 seemed to be localised at the cytoplasmic side of the cardiac sarcolemma. CONCLUSION: The p67 that was purified from bovine hearts could be a member of the annexin family of proteins. It might be a peripheral membrane protein associated with the cytoplasmic side of sarcolemma membranes.

Animals↗
PubMed1993

Activation of limulus coagulation factor G by several (1-->3)-beta-D-glucans: comparison of the potency of glucans with identical degree of polymerization but different conformations.

It has been demonstrated that both linear and branched (6-O-beta-D-glucosyl) (1-->3)-beta-D-glucans taking a single helical conformation are more effective than those taking a triple helical conformation for the activation of factor G from horseshoe crab amebocytes, as revealed by high-resolution solid-state 13C-NMR spectroscopy [Saitô, H. et al. (1991) Carbohydr. Res. 217, 181-190]. Annealing the linear glucan at 180 degrees C was essential to convert the conformation from the single helix to the triple helix. We found that heating of the glucan at such a high temperature resulted in depolymerization of the sample to molecular weight smaller than 10,000, which may influence the conformation and the above-mentioned biological activity. To eliminate ambiguity arising from the depolymerization of the glucan during annealing, we aimed to relate the biological activity to the conformation of samples whose chain lengths are identical, because the potency is known to depend on the molecular weight of the glucans. This molecular weight dependency of the potency, however, was found to be not the dominant factor, provided that the molecular weight is large enough to allow formation of the single helix conformation. Therefore, the single helical conformation of (1-->3)-beta-D-glucans is clearly demonstrated to be the dominant contributor to the activation of limulus coagulation factor G.

Animals↗