Biomedical subjects

Y Miyauchi

Publications and source records attributed to Y Miyauchi.

At least 109 records · Page 6Linked to original sources

PubMed1993

Prognosis in esophageal carcinoma with cervical lymph node metastases.

BACKGROUND: The purpose of this study was to assess cervical lymph node (C-LN) metastases and to examine whether the site of the C-LN metastasis impacts on survival of the patient with thoracic esophageal cancer. METHODS: Transthoracic esophagectomy and three-field dissection (mediastinal, abdominal, and C-LN) followed by esophageal reconstruction were performed on 68 patients with squamous cell carcinoma of the thoracic esophagus who were seen at our institution from 1983 to 1990. RESULTS: C-LN metastasis was seen in 20 (29.4%) patients, and the survival curve of the 20 patients with positive C-LN metastasis was not significantly different from that of the 48 patients without positive C-LN metastasis. The survival curve of patients (n = 7) with positive node limited to recurrent laryngeal nerve chain node (RLN group) was significantly better than that of patients (n = 13) with positive internal jugular nodes including supraclavicular nodes (IJN group) (p = 0.010; generalized Wilcoxon). This was because there were more patients in the IJN group (84.6%) than in the RLN group (28.6%) (p = 0.022) who had five or more positive nodes in the three fields. CONCLUSIONS: The results suggest that RLN should not be defined as M1 but as N1 in thoracic esophageal cancer.

Age Factors↗

PubMed1993

Simultaneous determination of nicotinic acid and its two metabolites in human plasma using solid-phase extraction in combination with high performance liquid chromatography.

A high performance liquid chromatographic method for the simultaneous quantitative determination of nicotinic acid, nicotinamide and nicotinuric acid in human plasma is described. The method is based on solid phase extraction in combination with ion-paired reversed phase high performance liquid chromatography. Recoveries of nicotinic acid, nicotinamide and nicotinuric acid are 92.9, 95.8 and 87.8%, respectively. The procedure shown was applied to the determination of the plasma time-concentration profile of nicotinic acid, nicotinamide and nictotinuric acid after nicotinic acid ingestion in humans.

Adult↗

PubMed1992

Ca(2+)-independent contraction of uterine smooth muscle induced by vanadate and its inhibition by Ca2+.

Vanadate, 30 microM, contracts uterine smooth muscle of estrogen-dominated non-pregnant rats in Ca(2+)-free medium after preincubation with 3 mM EGTA. In spite of the phosphorylation of the myosin light chain during this contraction, studies with fura-2 suggested that this contraction was not accompanied by an increase in the cytosolic Ca2+ level. Inhibitors of the myosin light chain kinase and protein kinase C partly inhibited this contraction. Vanadate seems to enter the cell through anion channels to inhibit phosphatases, resulting in phosphorylation via basal activities of the myosin light chain kinase and protein kinase C. An increase in the cytosolic free Ca2+ level resulted in relaxation of the contracting muscle in the same manner as in the oxytocin-induced Ca(2+)-free contraction.

Alkaloids↗

PubMed1992

Ca(2+)-dependent inhibition of Ca(2+)-independent contraction in uterine smooth muscle.

Uterine smooth muscle of the rat shows Ca(2+)-independent contraction in response to oxytocin in Ca(2+)-free medium. Micromolar Ca2+ inhibits this contraction. We now tested whether Ca2+ itself is the cause of this inhibition. The ratio of fura-2 fluorescence, the indicator of the intracellular level of Ca2+, was increased in parallel with the degree of inhibition by Ca2+. When inhibition was elicited by Ca2+, EGTA released the inhibition. Comparison of the dose-response curve for oxytocin in Ca(2+)-free solution and that in the medium with 1 microM Ca2+ showed that the inhibition by Ca2+ is non-competitive. EGTA chelation of the intracellular Ca2+ by loading of EGTA as its acetoxymethylester resulted in diminution of inhibition by Ca2+. EGTA suppressed the Ca(2+)-induced contraction but did not affect Ca(2+)-independent contraction. It is concluded that the inhibition is induced by intracellular Ca2+ itself.

Animals↗

PubMed1992

Synthesis of a cytochrome c derivative with prolonged in vivo half-life and determination of ascorbyl radicals in the circulation of the rat.

Since cytochrome c and acetylated cytochrome c disappear from the circulation with a half-life of 4 min, these proteins cannot be used for in vivo detection of superoxide radicals and related metabolites. To determine superoxide and other radicals in vivo, a cytochrome c derivative (SMAC) was synthesized by linking 1 mol of poly(styrene-co-maleic acid) butyl ester (SM) to cytochrome c, followed by acetylation of its lysyl amino groups. SMAC retained 8 and 80% of cytochrome c activity to react with ascorbyl and superoxide radicals, respectively. However, SMAC did not serve as a substrate for cytochrome c reductase and cytochrome c oxidase. When injected intravenously to the rat, SMAC circulated bound to albumin with a half-life of 130 min. SMAC was rapidly reduced in the circulation of intact animals. Treatment of animals with paraquat markedly enhanced the reduction of the circulating SMAC. We have synthesized an SM-conjugated superoxide dismutase (SOD) derivative (SM-SOD) that circulates bound to albumin with a half-life of 6 h. Kinetic analysis revealed that SM-SOD effectively inhibited the superoxide-dependent reduction of SMAC either in the presence or absence of 0.5 mM albumin. However, the reduction of the circulating SMAC was not inhibited by SM-SOD both in normal and paraquat-treated animals. Plasma samples from both animal groups also reduced cytochrome c and SMAC by an SOD-insensitive mechanism. However, after treatment with ascorbate oxidase, both plasma samples lost their activity to reduce cytochrome c and SMAC. These and other results suggest that ascorbyl radical might principally be responsible for the reduction of circulating SMAC and that plasma levels of ascorbyl radical might increase in paraquat-treated animals.

Acetylation↗

PubMed1992

Activation of human plasma prekallikrein by Pseudomonas aeruginosa elastase. II. Kinetic analysis and identification of scissile bond of prekallikrein in the activation.

Activation of human plasma prekallikrein by a bacterial metalloendopeptidase, Pseudomonas aeruginosa elastase, was reported (Shibuya et al. (1991) Biochim. Biophys. Acta 1097, 23-27). Details of the activation process were presently studied. The activation accompanied limited proteolysis of a peptide bond inside of a disulfide bridge of prekallikrein molecule. Amino acid sequencing analysis of the newly generated amino-terminal revealed that the cleavage site was Arg371-Ile372 bond which is the scissile bond in the activation of prekallikrein with trypsin-type proteinases. A pentapeptide substrate, 2-aminobenzoyl-Ser-Thr-Arg-Ile-Val-4- nitrobenzylamide, which contained the amino acid sequence identical to that around the scissile bond of prekallikrein was synthesized. Pseudomonal elastase, indeed, hydrolyzed the substrate at Arg-Ile bond with the kinetic parameters of Km = 118 microM, kcat = 1.56/s and kcat/Km = 1.33.10(4)/s M. These results indicated that the Arg371-Ile372 bond was sensitive not only to trypsin-type serine proteinases, but also a bacterial metalloproteinase. Kinetic analysis of the prekallikrein activation by pseudomonal elastase, however, revealed that the activation rate was slow, though the Km values was good enough to expect an occurrence of this activation in vivo (Km = 248 nM, kcat = 6.8.10(-4)/s, and kcat/Km = 2.7.10(3)/s M). The activation rate of prekallikrein by pseudomonal elastase in Hageman factor deficient plasma was remarkably improved when the plasma was reconstituted with purified Hageman factor molecule. From the results, a biological significance of the proteinase cascade in the plasma kinin generation was also indicated. The present in vitro study might support the hypothesis that the Hageman factor/kallikrein-kinin system plays an important role in bacterial infection including the pseudomonal one.

Amino Acid Sequence↗

PubMed1992

Antitumor effects of SMANCS on rat mammary tumor induced by 7,12-dimethylbenz[a]anthracene.

We previously found that a high-molecular-weight anticancer agent, polystyrene-co-maleic acid conjugated neocarzinostatin (SMANCS), in which two chains of styrene/maleic acid copolymer are conjugated to the anticancer protein neocarzinostatin (NCS), accumulated more selectively in tumor tissue than in normal tissue and was more stable than NCS in blood. These results indicate that SMANCS should have less systemic toxicity and a better therapeutic effect than NCS. In this study, the antitumor activity and adverse effects of SMANCS were compared with those of NCS by using rat mammary tumor induced by 7,12-dimethylbenz[a]anthracene. When tumors of rats, that had received 7,12-dimethylbenz[a]anthracene (20 mg/kg, one dose, p.o. in oily formulation), became palpable usually after 4-20 weeks, SMANCS treatment was initiated. Thirty days after i.v. administration of SMANCS (0.1 mg/kg 3 times and 0.3 mg/kg 3 times), tumors had shrunk in 35 of 37 rats (a mean weight was about 10% of control value; or decreased to about 30% of the value of before treatment in tumor weight); tumor size had not changed in 1 rat, and in the remaining 1 rat the tumor had enlarged. Thirty days after i.v. administration of NCS, tumors had shrunk in 8 of 14 rats, but the tumor size was unchanged in 1 rat and was enlarged in 5. In the control group, all tumors had enlarged. Development of new tumors was completely prevented by the administration of SMANCS. Histological examination of sequential slices of tumor revealed clear finding of degeneration and tumor encapsulation at 30 days after initial administration of SMANCS, with an accompanying fatty degeneration, but these effects were not observed for tumors treated with NCS. Although red blood cell counts and hemoglobin amounts decreased significantly in rats receiving NCS, no such effects were apparent in the SMANCS group.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1992

Factor XIII-dependent generation of 5th complement component(C5)-derived monocyte chemotactic factor coinciding with plasma clotting.

Blood coagulation or plasma clotting caused generation of a monocyte chemotactic factor(s) in vitro. The chemotactic factor, of which the apparent molecular mass was 75 kDa, shared antigenicity with complement C5 and possessed the affinity to monocytes, but not to polymorphonuclear leukocytes. The generation of the chemotactic factor was hindered in the presence of a thiol enzyme inhibitor, p-chloromercuriphenyl sulfonic acid, at the concentration of 1 mmol/l, although the gelation of plasma was apparently completed. Furthermore, the generation of chemotactic factor was not observed when a plasma deficient in blood coagulation factor XIII, which is a precursor of a thiol enzyme, plasma transglutaminase, was used; and the activity normally appeared when the deficient plasma was reconstituted with purified factor XIII or with a tissue transglutaminase prior to clotting. When the human sera were injected into guinea pig skin, the serum derived from normal plasma or from the reconstituted factor XIII deficient one caused mononuclear cell infiltration, however, the serum from the deficient plasma without reconstitution infiltrated to a significantly smaller extent. These results indicated that the complement system was initiated somehow during the clotting process resulting in the generation of the C5-derived monocyte chemotactic factor in cooperation with factor XIIIa (activated factor XIII).

Animals↗

PubMed1992

Expression of the transin, c-fos, and c-jun genes in rat transplantable osteosarcomas and malignant fibrous histiocytomas.

The expression of the transin, c-fos, and c-jun genes was assessed in transplantable osteosarcomas and malignant fibrous histiocytomas, as well as in pancreatic duct adenocarcinomas and hepatocellular carcinomas of rats and hamsters. Northern blot analysis revealed that both an undifferentiated osteosarcoma of spontaneous origin (SOS) and 4-hydroxyaminoquinoline 1-oxide (4-HAQO)-induced malignant fibrous histiocytomas with metastatic potential to the lung showed remarkably increased expression of transin mRNA transcripts. This was not the case for the other tumors. Interestingly, levels of transin mRNA were lower in lung metastatic lesions than in primary subcutaneous SOS tumors. The primary SOS and MFH expressed both c-fos and c-jun genes in conjunction with the transin gene, whereas the non-transin expressers, a 4-HAQO-induced osteosarcoma (COS) and the pancreatic duct adenocarcinomas, demonstrated one or the other, but not both. These results suggest a possible involvement of transin expression in the progression of spontaneous osteosarcomas and 4-HAQO-induced malignant fibrous histiocytomas in rats. Expression of the c-fos and c-jun genes may play a regulatory role in this process.

4-Hydroxyaminoquinoline-1-oxide↗

PubMed1992

Promotion of hepatic metastases by liver resection in the rat.

In the early period following radical hepatectomy for hepatoma, recurrences in the remaining liver are frequently found. In regenerating liver, implantation and growth of tumour cells released into the portal system during surgical treatment might be promoted. We examined the relationship between liver regeneration and the formation of metastases following hepatic resection. Intraportal injections of rat ascites containing hepatoma AH130 cells at a concentration of 1 x 10(5) cells 0.2 ml-1 were made at various periods following two thirds liver resection in rats. Tumour cell injections immediately at 24 h after surgery resulted in an increased number of hepatic metastases compared with control animals. Tumour cell injections 2 weeks after hepatectomy, however, had no significant difference in effect compared with control rats. In contrast, tumour cells injected immediately after removal of half of the caudate lobe resulted in the same number of metastases as control animals. These results demonstrate that the number of artificially induced hepatic metastases was increased during an initial period of active liver regeneration and was proportional to the volume of hepatectomy. The effect of 5-fluorouracil (5FU) or mitomycin C (MMC) as inhibitors of hepatic regeneration on liver metastasis after hepatectomy was studied. The administration of 5FU (20 mg kg-1) or MMC (0.2 mg kg-1) immediately, 24 and 48 h after hepatectomy resulted in a marked reduction in metastatic lesions. The administration of 5FU caused delays in weight gain and decreases in the wet weight of remaining liver, while MMC had no effect on either. Accordingly, results of 5FU administration may be due to inhibitory effects on liver regeneration whilst that of MMC administration may be due to cytocidal antitumour effect. The effect of OK-432 as an immunoactivator on the implantation and growth of tumour cells in regenerating liver was also studied. Pretreatment with OK-432, 0.5 mg intraperitoneally on 7 consecutive days, had no effect on hepatic metastases. The pathophysiology of liver regeneration may enhance hematogenous hepatic metastasis and release of tumour cells during surgical manipulation may represent an important cause of recurrence following hepatic resection.

Animals↗

PubMed1992

Effect of activated protein C on impaired fibrinolysis in rats with obstructive jaundice.

We studied the effect of activated protein C (APC) on impaired fibrinolysis using a rat model in which disseminated intravascular coagulation (DIC) is induced by the intravenous injection of endotoxin in rats with obstructive jaundice. An intravenous injection of endotoxin in rats with obstructive jaundice resulted in pulmonary hemorrhages and a marked increase in the plasma levels of tissue-type plasminogen activator (t-PA) antigen and plasminogen activator inhibitor activity. Prophylaxis with APC before the injection of endotoxin resulted in a decrease of the number of lung hemorrhages and an accelerated release of t-PA antigen. Thus, DIC in obstructive jaundice may be due to impairment of fibrinolysis and an increased susceptibility of endothelial cells to endotoxin. APC may be effective as a treatment for patients with obstructive jaundice associated with DIC.

Animals↗

PubMed1992

Right atrial myxoma presenting with recurrent episodes of pulmonary embolism.

We observed a right atrial myxoma presenting with recurrent episodes of pulmonary embolism, the diagnosis of which was made approximately 2 years after the initial symptoms appeared. We emphasize the importance of prompt recognition and subsequent surgical treatment of cardiac myxoma because embolism by tumor fragments is a potentially fatal complication of this condition.

Adult↗

PubMed1992

Glomerulopathy with IgA deposition in the dog.

In 100 dogs autopsied, glomerular IgA deposition was examined by the immunofluorescence technique and the histopathological features of glomeruli with IgA deposition were examined by light and electron microscopy. The incidence of the IgA deposition was age-related but there were no sex and breed predisposition. Deposition of IgA was observed mainly in mesangial areas in approximately a half (47%) of dogs examined. IgG, IgM and C3 often co-deposited. Histopathology of the glomeruli with IgA deposition indicated increase of mesangial cells, crescent formation, hemispherical deposits in paramesangial areas and glomerular sclerosis. Ultrastructurally electron dense substances positive for IgA deposited in mesangial and paramesangial areas. The examination to know the relation between the severity of IgA deposition and the number of mesangial cells or percent of the cells to total glomerular cells indicated that mesangial cells increased at the early stage of the disease and subsequently epithelial and endothelial cells proliferated as the increasing amount of IgA. Dogs suffering from enteritis or liver diseases showed high incidence of glomerular IgA deposition.

Animals↗

PubMed1992

Alpha-fetoprotein-producing pancreatic cancer--a case report and review of 28 cases.

The case of a female patient with an alpha-fetoprotein (AFP)-producing acinar cell carcinoma of the pancreas is reported, and 28 cases in the literature are reviewed. In our case, the serum AFP level declined drastically after removal of the tumor, but increased when widespread metastases appeared. AFP was detected in the cytoplasm of the cancer cells by immunohistochemical staining. Immunoelectron microscopic studies revealed AFP on the endoplasmic reticulum of the cancer cells. Of the 28 cases with AFP-producing pancreatic cancer, liver metastases were identified in 21 cases (76% overall). There was no correlation between the serum AFP level and liver metastases. Immunohistochemical studies revealed localization of AFP at the primary lesion in 6 out of eight cases tested. In cases of AFP-producing pancreatic cancer, serum AFP levels are useful for the diagnosis and as a marker for evaluating recurrent disease and therapeutic response, and for the management of gastrointestinal disease it should be remembered that some pancreatic cancers produce AFP.

Adenocarcinoma↗

PubMed1992

[Establishment and characterization of an ascites-forming rat osteosarcoma cell line].

A transplantable ascites-forming osteosarcoma (J. H. 1-AOS) derived from the 35th generation of spontaneous osteosarcoma, J. H. 1-OS, grown in Fischer 344 syngeneic rats was established. Tumorigenicity, histochemical and ultrastructural characteristics were investigated. Rats carrying the ascites form osteosarcoma died of cachexia about 15 days after transplantation, 1.5-2.5 x 10(6) cells/ml of tumor cells generally being involved in the ascites and tumor nodules formed in the mesentery. After inoculation into the back subcutaneous space, tumor growth was very rapid. Small round cells were detected in the Giemsa stain smear, and although osteoid formation was histologically lacking, cell surface alkaline phosphatase activity was noted both light and electron microscopically. Polyacrylamide gel electrophoresis demonstrated that alkaline phosphatase (Al-p) extracted from this tumor was consistent with Al-p from rat fetal calvaria. Thus maintenance of osteogenic potential is suggested for these ascites osteosarcoma cells, indicating their usefulness for further studies of biological behaviors of this tumor type.

Alkaline Phosphatase↗

PubMed1992

[A case of unilateral pulmonary edema associated rupture of mitral chordae tendineae].

A 57-year-old man was admitted with dyspnea and bloody sputum. The chest X-ray showed unilateral alveolar infiltration, and alveolar cell carcinoma was suspected. Physical examination showed orthopnea and a loud systolic murmur, and the echocardiogram showed mitral valve prolapse. A chest X-ray 4 days later revealed bilateral infiltration. The cardiac catheterization showed pulmonary congestion and the capillary wedge pressure revealed a prominent V wave. Papanicolaou's test of sputum was negative. These findings suggested heart failure due to mitral regurgitation rather than lung carcinoma. The patient underwent mitral valve replacement because of his refractoriness to the medical treatment. During the operation, the chordae tendineae of the anterior mitral leaflet was found to be completely ruptured. The mechanisms of unilateral pulmonary edema could not be ascertained, but the effect of posture and gravity was thought to be a possible mechanism.

Cardiac Catheterization↗

PubMed1991

Inhibition of post-ischemic reperfusion injury of the small intestine by diamine oxidase.

To elucidate the role of diamines in the pathogenesis of post-ischemic reperfusion-induced tissue injury, the effect of diamine oxidase was studied in the rat whose superior mesenteric artery was occluded for 15 min followed by 30 min reperfusion. Kinetic analysis using radiolabeled albumin revealed that the mucosal permeability of the reperfused small intestine increased significantly. Histological examination of the reperfused intestine revealed a marked degeneration of its mucosal layer. Intravenous administration of diamine oxidase inhibited the reperfusion-induced increase in mucosal permeability of the intestine almost completely and preserved the structure of the small intestine. H1-antagonist chlorphenilamine and H2-antagonist famotidine also inhibited the reperfusion injury of the small intestine. These and other results suggested that extracellular diamines might play critical roles in post-ischemic reperfusion-induced injury of the small intestine.

Amine Oxidase (Copper-Containing)↗

PubMed1991

Ultrastructural lipid and glycoconjugate cytochemistry of membranous lipodystrophy (Nasu-Hakola disease).

In order to assess the lipid and glycoconjugate characteristics of membranous lipodystrophy, a 29-year-old male with this disease was studied using an ultrastructural cytochemical approach. The specific membranocystic lesions of the disease are composed of cystic spaces and the lining membranes. The membranes were observed to have a two-layered character: microtubular structures in the layer adjacent to the spaces and a central amorphous zone. Lipid staining and the lipase digestion test revealed triglycerides localized not only in the cystic spaces but also in the microtubular structures. Lectin histochemical examination of carbohydrate components demonstrated that Maclura pomifera agglutinin bound strongly to the membranes, while Griffonia simplicifolia I, G. simplicifolia II, Concanavalia ensiformis and Triticum vulgaris agglutinin reacted weakly. Our results indicate the presence of triglycerides and carbohydrates with mainly alpha-D-galactose residues in the distinctive membranocystic lesions, in particular in the microtubular structures.

Adult↗