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Biomedical subjects

K Wakasa

Publications and source records attributed to K Wakasa.

At least 73 records · Page 4Linked to original sources
PubMed1998

Nuclear encoding of a plastid sigma factor in rice and its tissue- and light-dependent expression.

A full-length cDNA encoding a putative sigma factor for a plastid RNA polymerase was isolated from the higher plant Oryza sativa . The nucleotide sequence of the corresponding nuclear gene, named Os-sigA ( O.sativa sigma A), predicts a polypeptide of 519 amino acids that contains a putative plastid-targeting sequence in its N-terminal region. The predicted mature protein shows extensive sequence homology to bacterial sigma factors, encompassing the conserved regions 1.2, 2.1, 2.2, 2.3, 2.4, 3, 4.1 and 4.2 implicated in binding to -10 promoter elements, promoter melting and interaction with the core RNA polymerase enzyme. RNA blot analysis revealed that the abundance of Os-sigA transcripts was markedly greater in green shoots than in roots or in dark-grown etiolated shoots of rice seedlings. Furthermore, exposure of dark-grown etiolated seedlings to light resulted in a rapid increase in the amount of Os-sigA mRNA in the shoot. These observations suggest that regulation of expression of the nuclear gene for this putative plastid RNA polymerase sigmafactor by light contributes to light-dependent transcriptional regulation of plastid genes.

Amino Acid Sequence↗
PubMed1998

[Primary cardiac synovial sarcoma--a case report].

We report a case of cardiac synovial sarcoma, a very rare primary tumor of the heart. The patient was a 29-year-old man with chief complaint of dyspnea. On echocardiography, a tumor 42 mm in diameter occupying the most space of the left atrium was found. The tumor was obstructed the opening of the mitral valve. He was diagnosed with heart failure due to disturbance of the pulmonary venous return and hemodynamic mitral valve stenosis, and underwent surgery. The tumor was a 5-cm sphere originating in the left atrial posterior wall, and was covered with a sheath and solid. The atrial posterior wall was covered with a peel that appeared to be tumor tissue, and this tissue expanded toward the openings of the pulmonary veins bilaterally and the posterior cusp of the mitral valve. The tumor was resected together with the posterior wall. On pathologic examination, the tumor was diagnosed as a synovial sarcoma. Since no other primary focus was found, this tumor was judged to be a primary sarcoma of the heart. The patient was discharged with elimination of symptoms. The sarcoma recurred after 4 months, and the patient underwent a second operation. The recurrent tumor began from the site of resection of the previous operation and expanded up to the inferior pulmonary veins bilaterally. A wide area of the left atrial wall including the tumor was resected, and he was discharged again. The sarcoma recurred again, and he died of progression of heart failure and aggravation of general conditions after 8 months from the first operation.

Adult↗
PubMed1998

Osteolipoma in the parapharyngeal space.

We report our experience in managing a 58-year-old Japanese woman with a rare parapharyngeal interstitial cell tumor. Her main complaint was that of a submandibular swelling, which was diagnosed as osteolipoma histologically after resection.

Adipose Tissue↗
PubMed1998

Hepatocellular carcinoma with chondrosarcomatous variation: case report with immunohistochemical findings, and review of the literature.

Hepatocellular carcinoma with chondrosarcomatous variation is very rare. We report a case with the results of pathology examination, and review the literature. The patient, a 72-year-old may had a very large tumor in the liver revealed during follow-up for diabetes mellitus. The liver mass, which was 14 cm in diameter, was diagnosed as hepatocellular carcinoma by abdominal ultrasonography. Anterior segmentectomy and partial liver resection were performed. Histopathology examination revealed that the tumor consisted of two different components: the major one was hepatocellular carcinoma (HCC), which occupied most of the tumor; and a sarcomatous component, which occupied a smaller area, and included spindle-shaped cells with chondroscarcomatous variation. Intrahepatic metastases and tumor thrombi of HCC were also found in portal and hepatic veins. Investigations of the immunohistochemical localization of keratin (KRT), vimentin (VMT), and S-100 protein (S 100) were performed by the avidin-biotin complex method. Some of the spindle cells were immunohistochemically positive for both KRT and VMT, and the chondrosarcomatous cells were positive for S 100. These results strongly suggested that the sarcomatous lesion resulted from a sarcomatous change of HCC.

Aged↗
PubMed1998

Diagnostic potential and pitfalls of ultrasound-guided fine-needle aspiration cytology for breast lesions.

Ultrasound (US)-guided fine-needle aspiration cytology (FNAC) is now widely accepted as a diagnostic procedure for breast lesions. Along with its advantages, US-guided FNAC also has some pitfalls. The recognition of these pitfalls for this procedure is extremely important for the strict management of the disease. We retrospectively investigated the diagnostic potential and pitfalls of US-guided FNAC in the diagnosis of breast lesions. This study consisted of 348 aspirated samples from 274 breast tumors. The rate of sufficient aspirates was 74% after a single aspiration, while sufficient materials were finally obtained from 93% of the tumors by repeated aspirations. The rate was lower in tumors measuring less than 10 mm in diameter (62%), and in sclerosing adenosis (25%). The sensitivity of FNAC was 65%, the specificity was 75%, the border diagnosis rate was 18%, and the positive predictive value was 92%. The false-negative rate was higher in noninvasive carcinoma (45%). The border diagnosis rate was also higher in scirrhous carcinoma (29%). There were also five false-positive cases. Limited to nonpalpable lesions, the sufficient aspirates rate was 70% and the accuracy was 67%.

Adenocarcinoma, Scirrhous↗
PubMed1998

Adherent bacteria cells in five dental materials: sonication effect.

Adherent bacterial cells on the surfaces of two dental porcelain ceramics, three composite resins and human enamel were examined using four types of bacteria strains. Their adherent cells were counted on saliva-coated and uncoated material surfaces after sonication, and contact angle and zeta potential were measured for each adherent cell tested. A correlation between contact angle and bacterial cells on an uncoated surface was found to be higher in two Streptococcus sanguis cells than in S. mutans Ingbritt and S. sobrinus OMZ 176, whereas there appeared to be a higher correlation between S. mutans Ingbritt or S. sobrinus OMZ 176 and zeta potential on the uncoated surface. On the saliva-coated surface, a significantly high correlation was found between the adherent cells, with the exception of S. sanguis ATCC 10 557, and the zeta potential. Contact angle and zeta potential values were small when the surfaces of the materials were coated with saliva, as compared with those on the uncoated surface. The sonication condition (120 s) of adherent cells on the surface of the material significantly depended on the types of bacteria cells, showing that S. mutans Ingbritt (>50-60%) had a greater removal percentage than the others (<50%).

Journal Article↗
PubMed1998

Clinicopathological criteria for multicentricity of hepatocellular carcinoma and risk factors for such carcinogenesis.

Multicentric occurrence is an important characteristic of hepatocellular carcinoma. We evaluated clinicopathological criteria for multicentric hepatocellular carcinoma and identified risk factors for such carcinogenesis. Subjects were 251 consecutive patients undergoing liver resection for hepatocellular carcinoma. One kind of multicentric hepatocellular carcinoma had at least one tumor consisting of well-differentiated hepatocellular carcinoma, together with moderately or poorly differentiated hepatocellular carcinoma located in a separate region. The other kind had an area of well-differentiated component around hepatocellular carcinoma with less differentiation in all occurrences. The outcome of patients with tumors classified in this way was studied. Univariate and multivariate analyses were done to identify risk factors for multicentric hepatocellular carcinoma. The cumulative survival rate was significantly higher in patients with multicentric hepatocellular carcinoma than in patients with hepatocellular carcinoma associated with intrahepatic metastasis. Analysis by Cox's proportional hazard model showed that multicentricity was not a factor in the outcome. The risk of multicentric occurrence increases with progression of chronic liver disease. Univariate analysis showed hepatitis C virus marker and hepatitis B core antibody to be risk factors. By multivariate analysis, the odds ratio for multicentric occurrence in patients infected with hepatitis C virus and with serum hepatitis B virus core antibody compared with patients without either hepatitis C virus or hepatitis B virus was 10.86. This ratio in patients with hepatitis C virus alone was 4.30. These criteria for multicentric hepatocellular carcinoma seem to be clinically useful. Hepatitis C virus infection with or without former infection by hepatitis B virus is a strong risk factor for multicentric hepatocarcinogenesis.

Aged↗
PubMed1998

Hyperplastic foci in chronic liver disease: their proliferative activity assessed by nucleolar organizing region.

In the cirrhotic and precirrhotic liver, there may be small foci with increased cellularity and amphophilic cytoplasm. These are microscopic lesions that do not form macroscopically detectable nodules, which differ from the macroscopically apparent nodules of dysplastic nodules. In the present study, we assessed the proliferating activity of 12 hyperplastic foci in 11 patients with cirrhosis or chronic hepatitis, by staining for agyrophilic nucleolar organizing regions (AgNOR). The mean AgNOR count per nucleus in the hyperplastic foci ranged from 0.96 to 1.36 (mean, 1.13; SD 0.12), and from 0.81 to 1.06 (mean, 0.94; SD 0.08) in the controls. The AgNOR count in the hyperplastic foci was significantly higher than that in the controls (P < 0.01). Small hyperplastic foci show increased proliferative activity. Further study on these foci is required to clarify their relation to hepatocarcinogenesis.

Adult↗
PubMed1998

Granular cell tumor of the duodenum: a case report.

Granular cell tumor (GCT) in the duodenum is an extremely rare disease: only one case has been listed in a review, to date. We reported a 47-yr-old Japanese male case with GCT of the duodenum. Clinically, melena caused by bleeding from the tumor was the only symptom. The tumor cells showed abundant, granular eosinophilic cytoplasm. Although this tumor was clinically and histologically benign, highly developed tumor microvessels were demonstrated both angiographically and histologically, suggesting malignant potential of the tumor.

Duodenal Neoplasms↗
PubMed1998

Serous cystadenoma of the pancreas with atypical cells. Case report.

CONCLUSION: Serous cystadenomas of the pancreas may have the biologic ability to undergo malignant transformation. BACKGROUND: It is generally recognized that: serous cystadenomas of the pancreas are benign and that their malignant potential is low. METHODS: A serous cystadenoma of the pancreas was resected from a 53-yr-old woman. In the central portion of the tumor, papillary structures were found on the cyst wall. Immunohistologic studies using antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen were performed to determine the malignant potential of this tumor. RESULTS: On histology, most tumor cells were positive for periodic acid-Schiff but were negative for periodic acid-Schiff after diastase digestion and Alcian blue, a staining pattern typical of serous cystadenomas. The cells found in the papillary structure of the cyst wall were mildly atypical. These cells were stained with antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen, indicating that the cells comprising the papillary structure were proliferating more rapidly than cells in other parts of the tumor and strongly suggesting that the cells are premalignant.

CA-19-9 Antigen↗
PubMed1998

[A case of endometrioid carcinoma of the prostate].

A case of endometrioid carcinoma of the prostate is reported. A 64-year-old man was admitted to our department with initial macrohematuria and dysuria. The transrectal ultrasonogram showed remarkable prostatic hypertrophy and the serum level of both prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) ranged within normal limits. Urethrocystographical and cystoscopical findings indicated prostatic hypertrophy with elongation of prostatic urethra and mild trabeculation of bladder wall. During transurethral resection of the prostate, papillary tumor was accidentally found in the left lobe near the vermontanum. Histopathological examination revealed adenocarcinoma of the prostatic urethra and the tumor displayed no immunoreactivity for PSA or PAP. Under diagnosis of prostatic urethral cancer total cystoprostatectomy and urethrectomy were performed and ileal conduit was constructed for urinary diversion. As intraductal papillae and complex ramifying glands were histopathologically confirmed in the specimen and the immunohistochemical staining showed positivity of PSA and PAP, the tumor was diagnosed as endometrioid carcinoma of the prostate.

Carcinoma, Endometrioid↗
PubMed1998

Positron emission tomographic imaging of pleomorphic adenoma in the parotid gland.

We studied the possible correlation between 2-18F-2-deoxy-D-glucose (FDG) uptake and histopathological findings in mass lesions of the parotid gland. Thirteen pleomorphic adenomas of the parotid gland were evaluated by computed tomography (CT), magnetic resonance imaging (MRI), Gallium scintigraphy, Technetium scintigraphy and FDG-positron emission tomography (PET). Standardized uptake values (SUV) and time-activity curves (TAC) were determined for all mass lesions. Pleomorphic adenomas were histologically classified into the following three types: epithelial, intermediate and mesenchymal, based on their dominant histological components. The numbers of epithelial, intermediate, and mesenchymal types were 5, 2, and 6, respectively. The levels of SUVs were 4.02 +/- 1.91 (range: 1.97-7.07) in the epithelial type, 5.05 +/- 1.12 (range: 4.26-5.58) in the intermediate type and 3.98 +/- 7.74 (range: 1.98-7.74) in the mesenchymal type, respectively. The accumulation of FDG did not differ significantly among the three types. Since the accumulation of FDG was significantly correlated with the tumor size, FDG-PET could reflect tumor growth ability more apparently than the other nuclear or imaging modalities.

Adenoma, Pleomorphic↗
PubMed1997

Molecular evidence that most but not all carcinosarcomas of the uterus are combination tumors.

The pathogenesis of carcinosarcoma is still a subject of controversy. In the present study, molecular techniques were applied to determine the pathogenesis of uterine carcinosarcomas. The patterns of chromosome X inactivation were analyzed, targeting a portion of exon 1 of the human androgen receptor (HUMARA) in malignant epithelial and mesenchymal components. The presence of p53 and K-ras mutations were also analyzed. H&E-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected to obtain both epithelial and nonepithelial lesions from 25 carcinosarcomas, and DNAs were extracted by proteinase K digestion. Following treatment with methylation-sensitive restriction endonuclease (HhaI or HpaII), PCR amplification was performed using nested primers targeted to the HUMARA locus. Mutations in the p53 gene and K-ras gene were found in eight (32%) and six (24%) tumors, respectively. The patterns of chromosome X inactivation were different between the carcinomatous and sarcomatous components of three carcinosarcomas, indicating that these three tumors represent collision tumors. By contrast, the patterns of chromosome X inactivation, K-ras sequence, and p53 sequence were identical in both carcinomatous and sarcomatous components in 21 carcinosarcomas, indicating that these 21 tumors represent combination tumors. One case produced equivocal results that precluded determination of whether it represented a collision or combination tumor. These observations show that although most carcinosarcomas are combination tumors, some develop as collision tumors. The determination of histogenesis in individual cases of carcinosarcoma using molecular markers may be worthwhile, because the result could help predict the prognosis of individual cases and help guide clinical management.

Adult↗
PubMed1997

Clonal analysis of high-grade squamous intra-epithelial lesions of the uterine cervix.

We previously reported that invasive squamous cell carcinomas of the uterine cervix are of monoclonal composition. In the current study, we extended our previous work to determine the clonal composition of cases of high-grade squamous intra-epithelial lesion (HSIL). Clonal analysis targeting the HUMARA locus was performed on cervical tissue from 9 cases, 8 showing heterozygosity at the HUMARA locus and being, therefore, informative for clonality analysis. Uterine cervices were cut into 12 blocks, fixed with formalin and embedded in paraffin, and DNA was extracted from targeted lesions of each block. A total of 30 samples of cervical intra-epithelial neoplasia 3 (CIN3) (14 samples of carcinoma in situ and 16 samples of severe dysplasia) and 1 sample of CIN2 (moderate dysplasia) were analyzed. Monoclonal composition of the lesions was demonstrated in 30/30 cases of CIN3. Polyclonal composition was seen in the single case of CIN2. In 6 uterine cervices, in which dysplastic lesions were present in more than 3 blocks, the pattern of X-chromosome inactivation was the same in all lesions, suggesting that these individual lesions were derived from a single cell, with intraepithelial extension within the cervical mucosa. By contrast, one uterus contained 2 discontinuous dysplastic foci with different patterns of X-chromosome inactivation, indicating that the 2 lesions developed independently from each other. Our results demonstrate that (i) lesions of CIN3 (severe dysplasia and carcinoma in situ) are composed of a clonal neoplastic population of cells and (ii) most cases of HSIL are unifocal in origin.

Carcinoma in Situ↗
PubMed1997

Characterization of three cDNA species encoding plastid RNA polymerase sigma factors in Arabidopsis thaliana: evidence for the sigma factor heterogeneity in higher plant plastids.

By database search analysis, we identified three Arabidopsis EST (Expression Sequence Tag) entries having similarity to eubacterial RNA polymerase sigma factors. cDNA clones corresponding to these partial sequences were isolated, and the complete nucleotide sequences were determined. All three sequences encode proteins highly homologous to cyanobacterial and plastid sigma factors, and the gene products have N-terminal extensions which are assumed to function as plastid-targeting transit peptides. Thus we have concluded that the gene products are RNA polymerase sigma factors of plastids, and named sigA, sigB and sigC, respectively. Expression of these genes was analyzed by RNA gel-blot analysis and shown to be induced by illumination after a short-term dark adaptation. This strongly suggests that light regulation of the nuclear encoded sigma factor genes is involved in light-dependent activation of plastid promoters.

Amino Acid Sequence↗
PubMed1997

Alteration of p16 and p15 genes in common epithelial ovarian tumors.

We have examined the roles of 2 putative tumor-suppressor genes, the p16 and p15 inhibitor-of-cyclin-dependent-kinase genes, in the most commonly occurring epithelial tumors of the human ovary. Expression of p16 mRNA, examined by RT-PCR, was significantly reduced in 15 of the 48 tumors. Aberrant expression of p16 protein, detected by immunohistochemistry, occurred in 22 of 60 tumors, more frequently in low-grade tumors, and had significant correlation with low p16 mRNA expression. Hypermethylation of a site within the 5'-CpG island of the p16 gene was significantly associated with loss of p16 mRNA and protein expression. Homozygous gene deletion, evaluated by differential PCR analysis, was found in 2 tumors for the p16 gene and in 1 tumor for the p15 gene among 70 ovarian tumors examined. PCR-SSCP analysis detected point mutations in p16 in 4 tumors and in p15 in 1 tumor. One was a 38-bp deletion, from codons 48 to 60, in a mucinous tumor of low malignant potential; another was a non-sense mutation in codon 60 in a mucinous adenocarcinoma. The remaining 2 mutations were mis-sense mutations, one in codon 58 and the other in codon 60, in 2 endometrioid adenocarcinomas. We conclude that inactivation of p16, by loss of p16 mRNA and protein expression as a consequence of hypermethylation of the 5'-CpG island, rather than by gene deletion or point mutation, may play an important role in the genesis of human ovarian epithelial tumors.

Actins↗