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Biomedical subjects

S Miyoshi

Publications and source records attributed to S Miyoshi.

At least 127 records · Page 7Linked to original sources
PubMed1998

[A case of malignant lymphoma presenting as epididymal tumor].

A 56-year-old man visited our hospital with the complaint of painless swelling of right scrotal contents. Right orchiectomy was performed. Histopathological diagnosis was malignant lymphoma of the epididymis, without involvement of the testis. Bone marrow biopsy and Ga scintigram showed a normal pattern, while a swollen retroperitoneal lymph node (3 cm) was found by computed tomography (CT). The CT also showed a small mass lesion in the left upper lung field. After 2 courses of chemotherapy for malignant lymphoma, left upper lobectomy was performed at another clinic. Pathological diagnosis of the surgical specimen was moderately differentiated adenocarcinoma. The patient died without known causes, 8 months after the orchiectomy.

Adenocarcinoma↗
PubMed1998

[Surgical treatment of lung cancer with chest wall invasion].

From January 1986 to May 1998, 45 lung cancer patients with chest wall invasion (P3) underwent resection (40 male, 5 female), (median age 63.2 yrs (30-79)). Histological types were squamous cell carcinoma in 20, adenocarcinoma in 14, large cell carcinoma in 7, adenosquamous cell carcinoma in 2, and unknown in 2. Operative methods of lung resection were total pneumonectomy in 2, bilobectomy in 3, lobectomy in 38, and partial lung resection in 2. Resection was regarded as complete in 35 and incomplete in 10 patients. Thirty one patients had negative lymph nodes (N0), 9 had peribronchial or hilar lymph node metastases (N1), and 5 had mediastinal lymph node metastases (N2). The extent of tumor invasion to chest wall was P3a (invasion within parietal pleura) in 11, P3b-c (invasion to intercostal muscle) in 16, P3d (invasion to rib) in 18, patients. 5-year survival rate was totally 19.7%. Cisplatin based chemotherapy and concurrent thoracic radiation following surgery (CCRT) was performed in latest nine P3d cases. Partial response was observed in 5 of 9 cases (response rate 56%) and viable tumor cell in the primary site was not seen histologically in 5 of 9 cases. Three year survival rate was 46.9% for CCRT(+) 11.1% for CCRT(-). Acturial 5-year survival rate in P3a-d was 19.76%. P3d cases had poor survival, but CCRT improved prognosis of P3d cases.

Adult↗
PubMed1998

Impaired erythropoiesis in transgenic mice overexpressing a truncated erythropoietin receptor.

Erythropoietin (EPO), one of the pivotal regulators of erythrocyte production, transmits signals through the EPO receptor (EPOR). We have previously reported that human bone marrow (BM) cells express two dominant forms of the EPOR, one full-length and one truncated (EPOR-F and EPOR-T). Experiments with a cell line have shown that the EPOR-T acts as a dominant-negative regulator of EPOR-F-mediated signals. Its role in erythropoiesis in vivo, however, has yet to be clarified. Here we show the presence in mouse BM of a truncated form of the EPOR that is essentially the same as EPOR-T in humans. To investigate its role in vivo, we generated transgenic mice overexpressing mouse EPOR-T (EPOR-T-Tg mice). As a result, two independent EPOR-T-Tg lines were established. One line revealed mild anemia, but another line did not. When anemia was induced experimentally in these mice, however, both lines showed apparently poor recovery resulting in higher mortality than wild-type control mice. The impaired erythropoiesis found in these mice thus strongly suggests the EPOR-T's role as a negative regulator of erythropoiesis in vivo.

Anemia, Hemolytic↗
PubMed1998

Cells in the duct system of the rat submandibular gland.

The duct system of the rat submandibular gland (granular convoluted tubule [GCT], striated duct, excretory duct, main excretory duct [MED] and salivary bladder) was studied using scanning and transmission electron microscopy, with special reference to the dark and tuft cells. The MED was subjected to histochemistry for horseradish peroxidase (HRP) uptake. The epithelium of the duct system was composed of a heterogeneous cell population. On scanning electron-microscopic observation, principal, dark, and tuft cells were easily distinguished by their microvilli. Principal cells had small microvilli and microridges on their surface. The principal cells of the striated duct had secretory granules in the apical cytoplasm, but those of the excretory duct, the MED, and the salivary bladder had electron-lucent vesicles. Except for the GCT and salivary bladder, the basal infoldings of the epithelial cells were well developed. The dark cells were characterized by regular microvilli, and many tubules and vesicles confined to the apical cytoplasm. They existed in the striated duct, the excretory duct, the MED, and salivary bladder. The so-called pillar cells in the GCT appeared to be identical to the dark cells. Tuft cells had on their surface long, blunt microvilli with prominent rootlets. Many vesicles were observed in the apical cytoplasm. It was concluded that dark and tuft cells were common in the striated duct, the excretory duct, the MED and salivary bladder. Dark cells were observed also in the GCT. Dark and principal cells of the MED showed HRP uptake but tuft cells did not.

Animals↗
PubMed1997

p16INK4, pRB, p53 and cyclin D1 expression and hypermethylation of CDKN2 gene in thymoma and thymic carcinoma.

There have been few reports on genetic alterations in thymomas. To investigate the expression of p16INK4A, RB, p53 and cyclin D1 in thymomas, we first examined 36 thymomas (non-invasive type, 16 cases; invasive type, 20 cases) and 3 thymic carcinomas, using immunohistochemistry. Abnormal expression of p16INK4A, RB, p53 and cyclin D1 was observed in 18, 8, 10 and 7 cases, respectively. Only a subgroup of invasive thymomas and thymic carcinomas showed an inverse correlation between p16INK4A and RB expression. Subsequently, we examined the 36 thymomas and 4 thymic carcinomas for mutations in p53 and CDKN2 genes, using PCR-SSCP and direct-sequencing analyses. No mutation of these genes was detected in the thymomas and thymic carcinomas examined. A polymorphism in the 3' untranslated region of exon 3 of CDKN2 was detected in 5 cases of thymoma. We searched for hypermethylation in the promoter region of CDKN2, observing it in 4 thymomas and 1 thymic carcinoma. Our data suggest that, unlike other more common cancers, alteration of the p53 gene may not play a significant role in the tumorigenesis of thymoma. However, inactivation of p16INK4A and RB may play a role in the progression of thymoma and thymic carcinoma.

Blotting, Southern↗
PubMed1997

Heterologous expression, purification, and properties of diol dehydratase, an adenosylcobalamin-dependent enzyme of Klebsiella oxytoca.

Recombinant adenosylcobalamin-dependent diol dehydratase of Klebsiella oxytoca overexpressed in Escherichia coli was purified to homogeneity. The enzyme has a low solubility and was extracted from the crude membrane fraction with 1% Brij 35 in a high recovery. Subsequent chromatography on DEAE-cellulose resulted in 4.9-fold purification of the enzyme in an overall yield of 65%. The enzyme thus obtained showed specific activity comparable to that of the wild-type enzyme of K. oxytoca. The apparent molecular weight determined by nondenaturing gel electrophoresis on a gradient gel was 220,000. The enzyme consists of equimolar amounts of the three subunits with apparent Mr of 60,000 (alpha), 30,000 (beta), and 19,000 (gamma). Therefore, the subunit structure of the enzyme is most likely alpha2beta2gamma2. The recombinant enzyme was also separated into components F and S upon DEAE-cellulose chromatography in the absence of substrate. Components F and S were identified as the beta subunit and alpha2gamma2 complex, respectively. Apparent Km for adenosylcobalamin, 1,2-propanediol, glycerol, and 1,2-ethanediol were 0.83 microM, 0.08 mM, 0.73 mM, and 0.56 mM, respectively. The three genes encoding the subunits of diol dehydratase were overexpressed individually or in various combinations in Escherichia coli. The alpha and gamma subunits mutually required each other for correct folding forming the soluble, active alpha2gamma2 complex (component S). Expression of the beta subunit in a soluble, active form (component F) was promoted by coexpression with both the alpha and gamma subunits, probably by coexistence with component S. These lines of evidence indicate that each subunit mutually affects the folding of the others in this heterooligomer enzyme.

Chromatography, Ion Exchange↗
PubMed1997

Analysis of the early postoperative serum carcinoembryonic antigen time-course as a prognostic tool for bronchogenic carcinoma.

BACKGROUND: The serum kinetics of carcinoembryonic antigen (CEA) after resection of lung carcinoma are not well characterized. Its prognostic implications remain unclear. This study was designed to clarify the correlation between postoperative CEA time-course and patient prognosis. METHODS: The authors analyzed early postoperative CEA time-course in 31 lung carcinoma patients using nonlinear least square analysis with the following three equations: Equation 1: C(t) = C(0); Equation 2: C(t) = C(0)exp(-kt); and Equation 3: C(t) (C(0)PLAT)exp(-kt) + PLAT, in which t: postoperative day; C(t): postoperative CEA; PLAT: postoperative CEA at plateau; C(0): CEA at postoperative Day zero; and k: rate constant of elimination. The equation that yielded the least Akaike's information criterion was adopted as the best fitting regression equation for each patient. When Equation 3 was adopted, postoperative CEA production (PROD) was calculated as PLAT multiplied by k. RESULTS: Equations 1, 2, and 3 were adopted for 16 (Group 1), 0, and 15 (Group 2) patients, respectively. In Group 1, no decrease in serum CEA level after surgery was detected and CEA production appears to have been little or none. In Group 2, biologic CEA half-life was 1.1 +/- 0.7 days and was not useful for predicting patient prognosis. Tumor recurrences were observed in 9 of the Group 2 patients 19 +/- 9 months postoperatively and there was no significant difference in PLAT or PROD between patients with and without recurrence. Early recurrence within 6 months after surgery was recognized in 5 (early-REC) of the 15 Group 2 patients, in whom there was a tendency for PLAT to be higher than in the other 10 patients without recurrence (early-NON) (early-REC: 3.8 +/- 4.9 ng/mL; early-NON: 1.5 +/- 1.1 ng/mL; P = 0.08). PROD was significantly higher in early-REC than in early-NON (early-REC: 3.5 +/- 4.2 ng/mL/day; early-NON: 0.8 +/- 0.4 ng/mL/day; P < 0.05). CONCLUSIONS: Although PROD is more sensitive than PLAT, both parameters appear to be useful as prognostic tools for predicting early recurrence after resection of lung carcinoma. This is probably because they represent the number of residual tumor cells immediately after surgery.

Adult↗
PubMed1997

Characterization of a mutant of Vibrio vulnificus for heme utilization.

Vibrio vulnificus, an opportunistic human pathogen, can obtain iron from a variety of heme proteins. This process involves the digestion of heme proteins by an exoprotease to liberate protoheme (iron-protoporphyrin IX). In the present study, we isolated and characterized a mutant for protoheme utilization. One mutant isolated by treatment with a chemical mutagen was shown to be unable to use either protoheme or heme proteins, but multiplied in a medium supplemented with an iron siderophore, such as iron-vulnibactin. Like a wild-type strain, the mutant sensed iron depletion, so that the 74- and 79-kDa outer membrane proteins were expressed under iron-regulated conditions. Both the parent and mutant strains secreted hemolysin independent of the iron concentration of the medium. Whole cells of either of the strains were equally capable of binding of hematin. Taken together, the data suggest that the mutant may have a mutation in a gene encoding an inner membrane or a periplasmic protein which transports protoheme or iron dissociated from protoporphyrin IX into the cell.

DNA, Bacterial↗
PubMed1997

Fine structure of tuft cells of the main excretory duct epithelium in the rat submandibular gland.

BACKGROUND: Tuft cells, which are characterized by long microvilli with prominent rootlets and by vesicular and tubular profiles, are present in the mucosal epithelium of a number of hollow organs, including the main excretory duct of the rat submandibular gland. Despite their widespread occurrence, little is known of their function. METHODS: Main excretory ducts of the submandibular gland were obtained from 20 male Wistar rats and prepared for electron microscopic examination. Specimens also were subjected to various histochemical procedures, including HRP (horseradish peroxidase) uptake, the demonstration of catalase in peroxisomes, glycoconjugate cytochemistry, and ruthenium red staining. RESULTS: The features of the tuft cells in the MED (main excretory duct) basically were similar to those described in other organs. However, for the first time it was observed that in the submicrovillus zone and intermicrovillus space, there were many membrane-bound electron-dense granules, which resemble the so-called glycocalyceal bodies found on the apical surface of normal and neoplastic intestinal-type epithelial cells. Hypolemmal nerve terminals were seen to be in contact with the basal portion of tuft cells. After injection of HRP, reaction products were observed on the luminal surface of the microvilli, but not within the vesicles. Vesicles and tubules in the supranuclear cytoplasm exhibited a positive cytochemical reaction for glycoconjugates. The surface coat of tuft cell microvilli was stained with ruthenium red, but the vesicles and tubules in the supranuclear cytoplasm remained unstained. CONCLUSIONS: Our observations suggest that the tuft cells may engage in secretory activity in addition to reception.

Animals↗
PubMed1997

Some properties of nicked Vibrio vulnificus hemolysin.

Vibrio vulnificus, an opportunistic human pathogen, secretes the 50 kDa single-chain hemolysin. When incubated with an exocellular protease from this vibrio, the 50 kDa hemolysin was cleaved in some peptides joined with the disulfide bond(s); the 40 kDa fragment and the small fragment(s) undetectable in SDS-PAGE. The nicked hemolysin induced comparable hemolysis through the same process as that of the intact toxin. However, the nicked hemolysin was found to be more stable against inactivation due to autoaggregation, so that it formed a larger precipitation zone in the single radial immunodiffusion test using the antiserum against the intact hemolysin. These results suggest that V. vulnificus hemolysin is modified to be a more hydrophilic protein by nicking, while it is not accompanied by loss of the hemolytic activity.

Bacterial Proteins↗
PubMed1997

Estrogen receptor is not primarily responsible for altered responsiveness of ovalbumin mRNA induction in the oviduct from genetically selected high- and low-albumen chicken lines.

The role of estrogen receptor on ovalbumin mRNA induction by steroid hormones was investigated in primary cultures of oviduct cells from estrogen-stimulated immature chicks of genetically selected high- and low-albumen egg laying lines (H- and L-lines). In experiment 1, the extent of ovalbumin mRNA induction and changes in estrogen and progesterone receptors were compared between the oviduct cells from H- and L-lines with or without steroid hormones in the culture medium. In experiment 2, the effect of estrogen receptor gene transfection on the induction of ovalbumin mRNA was studied in the oviduct cells from the L-line chicks. The results showed a close correlation of the changes in ovalbumin mRNA with the numbers of nuclear and total estrogen receptors in the oviduct cells but not with the numbers of nuclear and total progesterone receptors. Estrogen receptor gene transfection induced ovalbumin mRNA to a moderate extent in the absence of the steroid hormones. To our surprise, however, estrogen receptor gene transfection apparently suppressed the ovalbumin mRNA responsiveness to estrogen to a considerable extent. It was concluded, therefore, that the extent of estrogen receptor expression might not be primarily responsible for the differences in responsiveness to steroid hormones of oviduct cells from genetically selected H- and L-line chickens.

Animals↗
PubMed1997

Analysis of the structural gene encoding a hemolysin in Vibrio mimicus.

An environmental isolate of V. mimicus, strain E-33, has been reported to produce and secrete a hemolysin of 63 kDa. The hemolysin is enterotoxic in test animals. The nucleotide sequence of the structural gene of the hemolysin was determined. We found a 2,232 bp open reading frame, which codes a peptide of 744 amino acids, with a calculated molecular weight of 83,903 Da. The sequence for the structural gene was closely related to the V. cholerae el tor hlyA gene, coding an exocellular hemolysin. The amino terminal amino-acid sequence of the 63 kDa hemolysin, purified from V. mimicus, was determined by the Edman degradation method and found to be NH2-S-V-S-A-N-N-V-T-N-N-N-E-T. This sequence is identified from S-152 to T-164 predicted from the nucleotide sequence. So, it seems that the mature hemolysin in V. mimicus is processed upon deleting the first 151 amino acids, and the molecular mass is 65,972 Da. Analyzing the deduced amino-acid sequence, we also found a potential signal sequence of 24 amino acids at the amino terminal. Our results suggest that, like V. cholerae hemolysin, two-step processing also exists in V. Mimicus hemolysin.

Amino Acid Sequence↗
PubMed1997

A case of widely split double P waves with marked intra-atrial conduction delay.

We report a 78-year-old man as the first documented case of double P waves separated by 400 msec on 12-lead ECG. These P waves had different polarities on lead V1. The first P wave represented activation of the lateral wall of the right atrium, and the latter P wave represented activation of the medial right atrium and the left atrium. Widely spaced double potentials were recorded craniocaudally along the line, presumably corresponding to the crista terminalis during sinus rhythm. For this to occur, conduction disturbance has to be present both in the upper and lower right atrium. Conduction disturbance in the upper right atrium would interrupt excitation from the sinus node to the medial wall, and conduction disturbance in the lower right atrium would interrupt excitation spreading from the lower lateral right atrium to the isthmus area where fragmented potentials were recorded. These multiple discrete lesions appear to constitute a unique electrical atriopathy in this patient.

Aged↗
PubMed1997

Hemagglutination is a novel biological function of lipopolysaccharide (LPS), as seen with the Vibrio cholerae O139 LPS.

It has been generally thought that the polysaccharide moiety of lipopolysaccharide (LPS) maintains only serological specificity, while the lipid A portion determines various biological functions. However, we found that hemagglutination was a common function of the polysaccharide moiety of LPSs from important human enteropathogenic bacteria. Of the LPSs examined, Vibrio cholerae O139 LPS showed the highest hemagglutinating activity. Glycoproteins, such as mucin and fetuin, showed efficient inhibition of the hemagglutinating ability. Since cell-mediated hemagglutination is known to be correlated with bacterial adherence, hemagglutination induced by the polysaccharide moiety is interpreted to indicate that cell-surface LPS is a potential adhesin.

Bacterial Adhesion↗
PubMed1997

Purification and characterization of a hemolysin produced by Vibrio mimicus.

Vibrio mimicus is a causative agent of human gastroenteritis. This pathogen secretes a pore-forming toxin, V. mimicus hemolysin (VMH), which causes hemolysis by three sequential steps: binding to an erythrocyte membrane, formation of a transmembrane pore, and disruption of the cell membrane. VMH with a molecular mass of 63 kDa was purified by ammonium sulfate precipitation and column chromatography with phenyl Sepharose HP and Superose 6 HR. The hemolytic reaction induced by VMH continued up to disruption of all erythrocytes in the assay system. Moreover, VMH that bound preliminarily to erythrocyte ghosts showed a sufficient ability to attack intact erythrocytes. These results suggest reversible binding of the toxin molecule to the membrane. The final cell-disrupting stage was effectively inhibited by various divalent cations. Additionally, some cations, such as Zn2+ and Cu2+, blocked the pore-forming stage at high concentrations. Although VMH could disrupt all kinds of mammalian erythrocytes tested, those from horses were most sensitive to the hemolysin. Horse erythrocytes were found to have the most toxin-binding sites and to be hemolyzed by the least amount of membrane-bound toxin molecules, suggesting that toxin binding to and pore formation on erythrocytes are more effective in horses than in other mammals. Purified VMH induced fluid accumulation in a ligated rabbit ileal loop in a dose-dependent manner. In addition, the antibody against the hemolysin obviously reduced enteropathogenicity of living V. mimicus cells. These findings clearly demonstrate that VMH is probably involved in the virulence of this human pathogen.

Ammonium Sulfate↗
PubMed1997

Vibrio mimicus attaches to the intestinal mucosa by outer membrane hemagglutinins specific to polypeptide moieties of glycoproteins.

Vibrio mimicus is the closest organism to Vibrio cholerae. V. mimicus E-33, which is a highly adhesive and enteropathogenic strain, is known to produce three types of hemagglutinins (HAs), i.e., a 31-kDa exocellular metalloprotease (Vm-HA/protease), lipopolysaccharide (Vm-LPSHA), and a 39-kDa major outer membrane protein (Vm-OMPHA). Hemagglutination induced by Vm-LPSHA and Vm-OMPHA was inhibited by glycoproteins, including mucin, fetuin, and asialofetuin, but not by monosaccharides, disaccharides, or N-acetylated saccharides. The inhibitory potential of each glycoprotein for Vm-OMPHA was greatly augmented by treatment with a glycolytic enzyme such as beta-D-galactosidase or beta-D-glucosidase, while pronase treatment achieved complete abolition of the inhibitory potential. The inhibitory ability of the glycoproteins for Vm-LPSHA was also abolished by pronase treatment; however, glycolytic enzyme treatment showed no effect. Hence, the polypeptide portion of glycoproteins may directly associate with Vm-OMPHA and Vm-LPSHA, but the sugar moiety may act as a barrier to interaction with Vm-OMPHA. The glycoproteins as well as Fab antibodies against Vm-OMPHA and Vm-LPSHA eliminated the ability of E-33 cells to agglutinate rabbit erythrocytes and to attach to rabbit intestinal mucosa. Additionally, expression of the hemagglutinating ability by the bacterial cells was accompanied by efficient bacterial adherence to the intestinal mucosa. Finally, the hemagglutinating activity of Vm-OMPHA was markedly increased by incubation with Vm-HA/protease. These results indicate that all three HAs may have significant roles in the glycoprotein-mediated intestinal adherence of V. mimicus E-33.

Animals↗
PubMed1997

Functional domains of a zinc metalloprotease from Vibrio vulnificus.

Vibrio vulnificus, an opportunistic human pathogen causing wound infection and septicemia, secretes a 45-kDa metalloprotease (V. vulnificus protease; VVP). A plasmid which carries the entire vvp gene subcloned into pBluescriptIIKS+ was transformed into Escherichia coli DH5alpha for overproduction of the protease. The 45-kDa recombinant protease (rVVP) was isolated from the periplasmic fraction of the transformant by ammonium sulfate precipitation followed by column chromatography on phenyl Sepharose. Biochemical characterization of the isolated rVVP showed that the recombinant protease was identical to that produced by V. vulnificus. When rVVP was incubated at 37 degrees C, a 35-kDa fragment was generated through autoproteolytic removal of the C-terminal peptide. This 35-kDa fragment (rVVP-N) was found to have sufficient proteolytic activity toward oligopeptides and soluble proteins but had markedly reduced activity toward insoluble proteins. Lineweaver-Burk plot analysis indicated increased Km values of rVVP-N for all of the protein substrates. rVVP, but not rVVP-N, was shown to agglutinate rabbit erythrocytes, bind to the erythrocyte ghosts, and digest the ghost membrane proteins. These results strongly suggest that rVVP (and VVP) consists of at least two functional domains: an N-terminal 35-kDa polypeptide mediating proteolysis and a C-terminal 10-kDa polypeptide which may be essential for efficient attachment to protein substrates and erythrocyte membranes.

Binding Sites↗