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Biomedical subjects

Y Mikami

Publications and source records attributed to Y Mikami.

At least 145 records · Page 8Linked to original sources
PubMed1998

Ovarian mucinous cystadenocarcinoma with malignant mural nodules.

A case of ovarian mucinous cystadenocarcinoma with malignant mural nodules is reported. The patient was a 28-year-old Japanese female (gravida 0, para 0) with a 2 year history of increasing abdominal fullness and edema of the lower extremity. Physical examination showed a large mass in the abdomen. An abdominal ultrasound and computed tomography demonstrated a multilocular cyst with a solid component. Lymph node and distant metastases were not found. These tests were followed by surgery. The resected right ovarian tumor measured 25 x 22 x 18 cm. On cut sectioning, it was multilocular with multiple mural nodules. Microscopically, the cyst wall was lined with papillary infoldings of atypical mucinous epithelium (intestinal type). Nuclear stratification, cribriform and back-to-back glandular patterns and stromal invasion were observed. In addition, the solid area of the mural nodules showed spindle or polygonal cells with increased mitotic activity including atypical mitoses. Nuclear pleomorphism was marked. Necrosis and hemorrhage were also present. Reticulin stain showed these pleomorphic cell clusters circumscribed by reticulin fibers and these cells were immunoreactive for vimentin and p53.

Adult↗
PubMed1998

Genetic analysis of Histoplasma capsulatum strains isolated from clinical specimens in thailand by a PCR-based random amplified polymorphic DNA method.

Thirteen strains of Histoplasma capsulatum were isolated from clinical specimens, including those from AIDS patients, in Thailand. Random amplified polymorphic DNA (RAPD) analysis with three different PCR primers showed that the DNA fingerprint patterns of the Thai isolates were very similar to each other and homogeneous, with only one exceptional strain, although the patterns were clearly different from those of a reference North American strain with all primers tested. Although the difference in the DNA fingerprinting patterns was minor, Thai isolates could be classified into two to four groups. A common PCR band (about 700 bp) in the patterns of all H. capsulatum strains was extracted, and its DNA sequence was determined. A new PCR primer set for the identification of H. capsulatum species was developed based on this sequence information. This primer set was 100% successful in the identification of the reference strain as well as all Thai isolates. The results of specificity tests of the primer set for the identification of the fungus are also discussed.

AIDS-Related Opportunistic Infections↗
PubMed1998

Seroprevalence and field isolation of bovine immunodeficiency virus.

A seroprevalence study of bovine lentivirus, known as bovine immunodeficiency virus (BIV), was conducted in 12 different dairy herds in Hokkaido, where some herds were a high prevalence of bovine leukemia virus (BLV) infection. Amongst 611 cattle, 28.6% of cattle were BLV-seropositive, and 11.7% of cattle were seropositive for BIV, while 4.2% of cattle were seropositive for both BIV and BLV. For the isolation of BIV, 19 samples of peripheral blood mononuclear cells (PBMC) and one sample of milk-derived leukocytes were prepared from BIV-seropositive cows. These PBMC and leukocyte preparations were then co-cultivated with cc81 cells, a cat cell line transformed by mouse sarcoma virus. BIV was isolated from 17 PBMC and one milk-derived leukocyte samples. The isolated viruses showed slow replication and syncytia formation. Major core antigen, p26 from these isolates were reacted with anti-BIV (American isolate R-29) serum. In addition, proviral DNA was detected in blood and milk samples by nested polymerase chain reaction and subsequent Southern blot hybridization. Nucleotide sequence analysis of the amplified pol gene products showed its 99.0 to 99.7% homology to that of BIV R-29. These results indicate that the Japanese BIV isolates appear to be antigenically and genetically similar to the American R-29. Since BIV was isolated from milk samples, BIV could possibly be transmitted through milk. This is the first report of BIV isolation in Japan.

Amino Acid Sequence↗
PubMed1998

Elevation of plasma peptide YY and pancreatic juice hypersecretion following massive small bowel resection in the rat.

To clarify a physiological role of endogenous peptide YY(PYY) on pancreatic exocrine secretion, gastrointestinal transit and bile flow, a hyper-PYY-emia model was constructed by performing a massive small bowel resection using rats. (1) 75% resection of the small intestine was performed at its distal side. Two weeks after surgery, these rats were fed a liquid meal, and intestinal transit of contents was observed and plasma PYY and secretin concentrations were measured by radioimmunoassay. (2) Two weeks after the same surgery, a liquid meal was infused into the duodenum, and both pancreatic juice and bile were collected separately under general anesthesia. Transit of the intestinal contents from the pyloric ring, plasma CCK concentrations, pancreatic juice flow, amylase output, and bile flow were determined. Hyper-PYY-emia occurred following surgery both at fasting and after feeding, accompanied by retardation of gastrointestinal transit, increase of pancreatic juice flow and decrease of bile flow. Plasma secretin levels were elevated slightly, while CCK levels remained unchanged. In conclusion, massive small bowel resection is a useful model to induce hyper-PYY-emia in rats. It is considered that, in a malnutritional state after small intestinal resection, a colonic regulatory mechanism, via humoral factors such as PYY, participates in the feedback regulation of proximal intestinal as well as of pancreatic function.

Animals↗
PubMed1998

Association of chronic infection of Chlamydia pneumoniae and coronary heart disease in the Japanese.

The association of Chlamydia pneumoniae with atherosclerosis of coronary and carotid arteries and the aorta has been demonstrated by seroepidemiology and by detection of the organism in atheromata. We investigated the frequency of C. pneumoniae seropositivity in patients with acute myocardial infarction (AMI). C. pneumoniae-specific antibodies were measured by the microimmunofluorescence test in 160 AMI patients and 160 control subjects matched for age and gender. The odds ratios (ORs) were 2.2 (95% confidence interval (CI), 1.2 to 3.9) for immunoglobulin (Ig)G and 2.7 (95% CI, 1.7 to 4.3) for IgA. After adjustment for other cardiovascular risk factors of age, gender, hypertension, diabetes, cigarette smoking and serum cholesterol, the ORs were essentially unchanged. This study confirmed that the observations of an association between antibody against C. pneumoniae and coronary heart disease in Western nations is also present in Japan. Our results are comparable to the previous seroepidemiological studies reporting ORs of 2.0 or greater.

Antibodies, Bacterial↗
PubMed1998

[Evaluation of the E-test: comparison of E-test and microbroth dilution method in azole antifungal susceptibility test].

The susceptibilities of clinical isolates of Candida spp. to fluconazole (FLCZ), itraconazole (ITCZ) and ketoconazole (KCZ) were determined by a new method, E-test (AB BIODISK, Sweden) and compared with those obtained by the microbroth dilution method. The MIC values of the 3 azoles obtained by the two methods were, in general, in good agreement. While MICs of FLCZ and KCZ demonstrated higher essential agreement rates and better correlation by both methods, MIC values of ITCZ by the E-test had a tendency to be higher than those of the microbroth dilution method in azole resistant strains. Potential usability of E-test as a broth dilution method for susceptibility tests for clinically isolated Candida spp. including azole resistant strains was discussed.

Antifungal Agents↗
PubMed1998

Demethyl mutactimycins, new anthracycline antibiotics from Nocardia and Streptomyces strains.

New anthracycline antibiotics 3'-O-demethyl mutactimycin (3) and 4-O,3'-O-didemethyl mutactimycin (4) were isolated from two actinomycetes strains, Nocardia transvalensis and Streptomyces sp. GW 60/1571. The chemical structures were elucidated by mass spectrometry and NMR spectroscopy. Antibiotic 3 displayed moderate antimicrobial activity against Gram-positive bacteria and cytotoxicity against P388, L1210 and HeLa tumor cells (IC50; 9.6, >25 and 20 microg/ml, respectively).

Animals↗
PubMed1998

Anemia-inducing factor expressed in gastric cancer is homologous with complement regulatory factor CD59?

Anemia-inducing factor (AIF) was isolated from gastric cancer tissue; however, the human placenta used as the volume of AIF for further analysis did not prove sufficient. This substance was named placental anemia-inducing factor (PAIF). PAIF directly reduces the number of erythrocytes in vitro and reduces the RBC count in rabbits to 80% when i.v. administration of 27 microg/kg of body weight is given. The aim of this study is to better define PAIF and to examine whether the identifical substance expresses on either the surface or in the cytoplasm of established gastric cancer cell lines. PAIF is a glycoprotein with about 20 KD, whose 17 amino acid residues of N terminus were sequenced after Edman treatment. The N-terminus of PAIF were determined as Lqcyncpnptadcktav. This is homologous with that of CD59, which is thought as a regulator of membrane attack complex of complement system. Expression of PAF or CD59 in four established gastric cancer cell lines were examined by indirect immunofluorescence method and by Northern blot hybridization. The cells (1 x 106) were seeded into plastic plates for three days and reacted overnight at 4 degrees C in 0.5 ml of PBS with anti-PAIF polyclonal antibody or with anti CD59 rat monoclonal antibody. Both PAIF and CD59 were stained positively on the surface and/or in the cyroplasm. The total RNAs were prepared from the four kinds of cell lines and normal human lymphocytes. CD59 mRNA was probed in all cell lines by BamH1-EcoR1 fragment of PSRa CD59. The signal levels of MKN-28, MKN-45 and KATO-III were stronger than that of MKN-74, whereas the signal of normal lymphocytes was the lowest. Although there is no decisive evidence that PAIF is exactly the same substance as CD59, and although the biological functions of these two substances are conflictive, and still to be further investigated, the 17 amino acid residues of N-terminus of PAIF expressed in gastric cancer cells were homologous with those of CD59. A derivative of CD59 may exist in gastric cancer.

Amino Acid Sequence↗
PubMed1997

Reconstitution, morphology and crystallization of a fatty acid beta-oxidation multienzyme complex from Pseudomonas fragi.

The fatty acid beta-oxidation multienzyme complex from Pseudomonas fragi, HDT, exhibits predominantly the three enzymic activities of 2-enoyl-CoA hydratase (EC 4.2.1.17), 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) and 3-oxoacyl-CoA thiolase (EC 2.3.1.16). The HDT complex is encoded by the faoAB operon, consisting of the faoA and faoB genes that encode two individual constituents, the alpha-subunit and the beta-subunit. We have constructed Escherichia coli overexpression systems for the faoAB gene product (coexpression of the alpha- and beta-subunits), the alpha-subunit alone and the beta-subunit alone, and have purified the three respective products. Gel-filtration analysis revealed that the faoAB gene product forms a heterotetrameric structure, alpha2beta2, identical with the native HDT oligomeric state from P. fragi, whereas the alpha-subunit and beta-subunit individually form dimers. Electron microscopy demonstrated that each protein morphologically adopts the above oligomeric structures. The HDT complex, reconstituted in vitro from the isolated alpha- and beta-subunits, exhibits the three original enzymic activities and yields the same crystal as those from the native enzyme. CD measurements indicated that the alpha- and beta-dimers hardly alter their global conformations upon the formation of the HDT complex. Interestingly, the beta-dimer alone does not exhibit 3-oxoacyl-CoA thiolase activity, whereas the alpha-dimer alone exhibits both the 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase activities. These results suggest that the contact between the alpha- and beta-subunits is essential for the thiolase activity. We have identified several structurally important proteolytic sites within each subunit, which are protected in the intact heterotetrameric molecule. These findings allow the possible location of the interface between the two subunits, which should be crucial for the exhibition of thiolase activity.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1997

Promoters of epithelialization induce expression of vascular endothelial growth factor in human gastric epithelial cells in primary culture.

Both epithelialization and angiogenesis are indispensable processes in gastric ulcer healing. Coordination between these processes has not been well studied. In the present study, we have established a new primary culture system of human gastric epithelial cells and investigated the effect of epithelialization stimulants on a specific angiogenic factor, vascular endothelial growth characterized as epithelial cells. Both epithelialization stimulants, hepatocyte growth factor (HGF) and epidermal growth factor (EGF), significantly stimulated vascular EGF expression in gastric epithelial cells. HGF and EGF receptors were expressed by the cells, suggesting that regulation may be mediated through specific receptors.

Adult↗
PubMed1997

Expression of vascular endothelial growth factor at the human gastric ulcer margin and in cultured gastric fibroblasts: a new angiogenic factor for gastric ulcer healing.

Angiogenesis plays a pivotal role in gastric ulcer repair. Several growth factors are involved in angiogenesis, and of these, vascular endothelial growth factor (VEGF) has received considerable attention, since it is the only factor that specifically acts on endothelial cells. However, the role of VEGF in gastric ulcer repair is not known. In the present study, we demonstrate the specific expression of VEGF at the gastric ulcer margin, using immunohistochemistry and RT-PCR. The specific receptors of VEGF, flt-1 and KDR were also detected in gastric mucosa. We further demonstrate the expression of VEGF by cultured human gastric fibroblasts which is enhanced by tumor necrosis factor-alpha. These data suggest that VEGF may play a role in angiogenesis in the process of gastric ulcer healing.

Base Sequence↗
PubMed1997

Early surgical management of invasive gingival aspergillosis in a neutropenic patient with leukemia: a case report.

Primary invasive aspergillosis of the oral cavity is a rare but serious complication in immunocompromised patients. We report a case of gingival Aspergillus infection in a neutropenic patient with acute myelogenous leukemia, who was successfully treated by an early surgical approach in combination with antifungal medication and granulocyte colon stimulating factors.

Adult↗
PubMed1997

Serotyping of Cryptococcus neoformans strains isolated from clinical specimens in Thailand and their susceptibility to various antifungal agents.

One hundred and thirty-nine strains of Cryptococcus neoformans were isolated in Thailand from clinical specimens including 97 AIDS patients: 67 from Northern, 48 from Central, 17 from Northeastern and 7 from Southern regional hospitals. Six out of the 139 strains were serotype B and the remaining 133 were A. There was no correlation between serotypes and regional distribution. To our knowledge, this is the first report of serotyping studies on C. neoformans in Thailand. Studies on random amplified polymorphic DNA (RAPD) analysis showed that this method is useful for the differentiation of C. neoformans var. gattii (serotypes B and C) and C. neoformans var. neoformans (serotypes A and D). They also indicated that Thai isolates of C. neoformans var. gattii (serotype B) were a homogeneous group on the basis of their genotypes. Antifungal susceptibility tests using 5 antifungal agents including amphotericin B, fluconazole, flucytosine, itraconazole and micronazole against 50 selected strains of C. neoformans showed that they were sensitive to all of the antifungal agents tested except for one strain that was resistant to flucytosine.

AIDS-Related Opportunistic Infections↗
PubMed1997

Continuous infusion of 5-fluorouracil plus low-dose cisplatin in tumor-bearing mice.

Combination chemotherapy with 5-fluorouracil (5-FU) and cisplatin is widely used but the optimal daily dose of the latter has not been established. The present study was designed to determine the pharmacodynamic interaction and antitumor effect of these drugs when used at clinically relevant doses in animals. Male ddY mice were injected with Sarcoma 180 cells and then given a continuous infusion of 5-FU (10 mg/kg/day) for 5 days (via an implanted micropump) +/- cisplatin 1 mg/kg by i.p. bolus (pharmacodynamic study). Alternatively, mice were given 5-FU +/- cisplatin (0.2 mg/kg/day), cisplatin alone for 5 days or no treatment (anti-tumor effect study). Tissue and serum samples were taken for analysis. No significant differences in serum pharmocokinetics were observed between the groups at any timepoint but 0.5 h after the start of infusion, where the serum 5-FU concentration was lower with monotherapy than with combination therapy. 5-FU alone had a slight antitumor effect, while low-dose cisplatin alone had no noticeable effect. 5-FU + cisplatin produced a favorable response, with a significantly lower treated/control tumor weight ratio than in the non-treated and cisplatin monotherapy groups (p < 0.05), although this was not significantly different from the response to 5-FU monotherapy. In conclusion, the dose of cisplatin used in the present study was insufficient to generate a significant tumor response alone but it did tend to enhance the antitumor efficacy of 5-FU. Continuous 5-FU infusion plus low-dose daily cisplatin may become clinically useful after further investigation.

Animals↗
PubMed1997

Adenoid basal carcinoma of the cervix uteri: a case report.

We report a rare case of adenoid basal carcinoma of the uterine cervix, unexpectedly found in a uterus resected for the treatment of cervical intraepithelial neoplasia (CIN) 3. The patient was a 47-year-old Japanese female. She received a total abdominal hysterectomy under a diagnosis of CIN 3 of the cervix. Grossly, there were no significant findings in the surgical specimens. Microscopically, in seven of the 12 blocks of the cervix examined, scattered small nests of uniform small cells, which extended 4 mm below the epithelial surface, with dark nuclei and scant cytoplasm were observed. Peripheral palisading as well as the formation of gland-like or acinar structures were noted. The latter were positive for mucicarmine. Stromal reaction was not obvious. There were also foci of squamous differentiation in some portions of the small nests. Occasional mitoses as well as large atypical cells were also seen in this area. Immunohistochemically, the foci of squamous differentiation were positive for carcinoembryonic antigen. The epithelial surface in other portions showed CIN 3 with crypt extension. Distinction between adenoid basal carcinoma of the cervix and other diseases, such as adenoid cystic carcinoma and squamous cell carcinoma with basaloid features, is important for clinical management because the clinical behavior of adenoid basal carcinoma is less malignant.

Carcinoma↗
PubMed1997

Intramural sarcoma of the carotid artery with adventitial inflammation and fibrosis resembling 'inflammatory aneurysm'.

A rare case is described of an intramural sarcoma of the right common carotid artery coexisting with adventitial inflammation and fibrosis, resembling 'inflammatory aneurysm', which was resected from a 33-year-old Japanese woman who had presented with a pulsatile mass on the right side of the anterior neck. Grossly, the wall of the carotid artery showed an intimal tear with dissection of the media filled with thrombus. A grayish area, abutting directly onto the dissected space and involving the media and inner adventitia, was composed of alpha-smooth muscle actin-positive and desmin-negative polygonal and spindle cells with large blunt-ended nuclei and coarse granular chromatin arranged into a well-organized interlacing bundle pattern. This portion was thus considered to represent leiomyosarcoma. White to yellow-tan fibrotic tissue present in the adventitial area consisted of extensive lamellar fibrosis with scattered foci of lymphoplasmacytic aggregates and obliterated arteries, and lacked atypical spindle and polygonal cells. These changes accorded with the histopathological findings hitherto described in cases of 'inflammatory aneurysm', which is known to almost exclusively involve the abdominal aorta. We consider this case unique in that the leiomyosarcoma involved an artery other than the aorta, with an 'inflammatory aneurysm'-like reaction in the same site. The possible relationship between these two conditions is discussed.

Adult↗