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Biomedical subjects

K Wakasa

Publications and source records attributed to K Wakasa.

At least 55 records · Page 3Linked to original sources
PubMed2000

Excellent results of postoperative radiotherapy for endometrial stromal sarcoma of low-grade malignancy.

Endometrial stromal sarcoma of low-grade malignancy (ESSL) is a rare neoplasm, and neither preoperative diagnostic procedures nor standard therapy have yet been established. We treated 3 cases of ESSL in the past 27 years, and we report here one of these cases that was classified as stage III (according to the FIGO classification of endometrial carcinoma). Postoperative radiotherapy was used to treat a residual tumor, and the patient showed a complete response.

Adult↗
PubMed2000

Evidence of chemical bonding at biomaterial-hard tissue interfaces.

For many years, glass-polyalkenoate cements have been described as possessing the unique properties of self-adherence to human hard tissues, such as bones or teeth. However, direct experimental evidence to prove the existence of chemical bonding has not been advanced. X-ray Photoelectron Spectroscopy (XPS) was used to analyze the chemical interaction of a synthesized polyalkenoic acid with enamel and synthetic hydroxyapatite. For both enamel and hydroxyapatite, the peak representing the carboxyl groups of the polyalkenoic acid was detected to have significantly shifted to a lower binding energy. De-convolution of this shifted peak disclosed two components with a peak representing unreacted carboxyl groups and a peak suggesting chemical bonding to hydroxyapatite. On average, 67.5% of the carboxyl groups of the polyalkenoic acid were measured to have bonded to hydroxyapatite. XPS of hydroxyapatite also disclosed its surface to be enriched in calcium and decreased in phosphorus, indicating that phosphorus was extracted at a relatively higher rate than calcium. Analysis of these data supports the mechanism in which carboxylic groups replace phosphate ions (PO4(3-)) of the substrate and make ionic bonds with calcium ions of hydroxyapatite. It is concluded that an ultrathin layer of a polyalkenoic acid can be prepared on a hydroxyapatite-based substrate by careful removal of non-bonded molecules. With this specimen-processing method, XPS not only provided direct evidence of chemical bonding, but also enabled us to quantify the percentages of functional groups of the polyalkenoic acids that bonded to calcium of hydroxyapatite.

Binding Sites↗
PubMed2000

Expression of interferon alpha/beta receptor in human hepatocellular carcinoma.

Interferon-alpha (IFNalpha) plays a crucial role in the antiproliferation and immunoregulatory activity through the specific cell surface receptor, interferon-alpha/beta receptor (IFNalpha/betaR). We examined the immunohistochemical expression of IFNalpha/betaR in 91 hepatocellular carcinoma (HCC), HCV-related chronic hepatitis (n=38) and cirrhosis (n=53), dysplastic nodules (n=5), and normal liver (n=9). The level of IFNalpha/betaR increased in chronic hepatitis and cirrhosis compared with normal liver. All the dysplastic nodules showed moderate or high expression. In HCCs, 26% (24/91) of patients showed high IFNalpha/betaR expression while the remaining 38% (35/91) showed moderate, and 35% (32/91) no or faint expression. Clinicopathological survey demonstrated a significant correlation between IFNalpha/betaR expression and differentiation of carcinoma (P=0.0008) although there was no correlation between IFNalpha/betaR expression in HCC and survival or disease-free survival. Thus, IFNalpha/betaR was expressed not only in chronic hepatitis or liver cirrhosis but in HCC and its expression was significantly correlated with tissue differentiation of carcinoma.

Blotting, Western↗
PubMed1999

A novel approach to AFM characterization of adhesive tooth-biomaterial interfaces.

A novel approach is proposed for studying tooth-biomaterial interactions with high resolution. Thus far, polished interfaces examined by AFM have not disclosed much detail, mainly due to the destruction of soft surface texture and the smearing of polishing debris across the interface that obscures the actual ultra-structure. Therefore the practical utility of diamond-knife microtomy as a sample preparation technique for imaging tooth-biomaterial interfaces by AFM with high resolution was tested in this study and compared to that of ultra-fine mechanical polishing techniques. The AFM images clearly demonstrated the enhanced potential of diamond-knife microtomy for nondestructively producing clean cross-sections through interfaces that allow the interfacial ultra-structure to be imaged by AFM with a resolution equaling that of TEM. This novel approach opens the field to the full range of scanning probe microscopy, including physical and chemical surface characterization of interfaces with a mix of soft and hard substrates.

Dental Cements↗
PubMed1999

Influence of histological inflammatory activity on regenerative capacity of liver after percutaneous transhepatic portal vein embolization.

Percutaneous transhepatic portal vein embolization (PTPE) produces regenerative hypertrophy in the nonembolized part of the liver, but the regenerative capacity after PTPE in patients with chronic hepatitis is unknown. We studied 34 patients with hepatocellular carcinoma and chronic hepatitis who underwent PTPE at the right portal vein. Hepatic lobular volumes were calculated by computed tomography before and 2 weeks after PTPE. The increase in left lobular volume was analyzed using a stepwise multiple regression method incorporating 11 factors: age; portal venous pressure; proportional volume of the right lobe; indocyanine green retention test; platelet count; serum levels of aspartate transaminase, alanine transaminase, total bilirubin, and albumin; and histological inflammatory grade and stage of fibrosis, according to the criteria of the International Association for the Study of the Liver recommended at their 1994 meeting. The median volume of the left lobe had increased from 405 to 554 cm3 (P < 0.0001) by 2 weeks after PTPE. Inflammatory grade was the only independent factor predicting regenerative hypertrophy (regeneration ratio (%) = 80.3 - 20.1 x grade; standard correlation coefficient = -0.566; P = 0.0014). Histological inflammatory activity was the essential factor regulating liver regeneration after PTPE in patients with chronic hepatitis.

Aged↗
PubMed1999

Neuroendocrine carcinoma of the sigmoid colon: report of a case.

Neuroendocrine carcinoma of the colon is a rare entity; however, this type of tumor is known for its aggressive progression and poor prognosis. A case of a 56-year-old Japanese male is presented in this report. A huge, child's head-sized tumor was found to have grown extraluminally on the sigmoid colon with multiple liver metastases. The tumor measured 16.5 x 15 x 8.2 cm in size and weighed 1 300 g. The patient died of hepatic failure due to massive liver metastases 6 months after operation. The pathological findings including an electron microscopic analysis were correlated with those of neuroendocrine carcinoma. We reviewed the English literature, and analyzed 94 cases of neuroendocrine carcinoma which had been reported previously. The nomenclature and definition of this disease still remains somewhat unclear, and not a small population of this disease may thus have been misdiagnosed and treated as other less aggressive entities. The necessity to make an accurate differential diagnosis in such cases is thus emphasized.

Carcinoma, Neuroendocrine↗
PubMed1999

Effect of tannic acid solution on collagen structures for dental restoration.

This study examined the effect of tannic acid solution on dissolution of dentine collagen and morphological aspects of tendon collagen. Using root dentine, which was cut off from bovine anterior tooth, dentine powders were obtained by the pulverization and lyophilization. They were subject to an application of 1, 3, 5 or 10% tannic acid (TA) solution for 1, 3, 6, 12 or 24 h. TA-treated dentine powders were treated with 40% phosphoric acid (PA) for 30 s at 20 degrees C and additionally with trypsin. Released hydroxyproline in Woessner's assay after a hydrolysis in 6 N HCl at 110 degrees C for 20 h was assumed to be dissolved dentine collagen. Released hydroxyproline in a control sample without acid treatment decreased from 100 to about 60% with increased TA concentration of 1 to 10%, and decreased with increased incubation times of 1 to 24 h when applied by 5% TA solution. Scanning electron microscopy results established the morphological effect of their surface characteristics due to such treatments as 40% PA for 30 s and 5% TA for 6 h, or 40% PA after 5% TA treatment, yielding collagen structures protected by TA to attack from phosphoric acid.

Journal Article↗
PubMed1999

Alteration of p16 and p15 genes in human uterine tumours.

The roles of the p16 and p15 inhibitor of cyclin-dependent kinase tumour suppressor genes were examined in human uterine cervical and endometrial cancers. p16 mRNA, examined by reverse transcription polymerase chain reaction (RT-PCR), was significantly reduced in five of 19 (26%) cervical and four of 25 (16%) endometrial tumours. Reduced expression of p16 protein, detected by immunohistochemistry, occurred even more frequently, in nine of 33 (27%) cervical and seven of 37 (19%) endometrial tumours. Hypermethylation of a site within the 5'-CpG island of the p16 gene was detected in only one of 32 (3%) cervical tumours and none of 26 endometrial tumours. Homozygous p16 gene deletion, evaluated by differential PCR analysis, was found in four of 40 (10%) cervical tumours and one of 38 (3%) endometrial tumours. Homozygous deletion of p15 was found in three of 40 (8%) cervical tumours and one of 38 (3%) endometrial tumours. PCR-SSCP (single-strand conformation polymorphism) analysis detected point mutations in the p16 gene in six (8%) of 78 uterine tumours (four of 40 (10%) cervical tumours and two of 38 (5%) endometrial tumours). Three were mis-sense mutations, one in codon 74 (CTG-->ATG) and one in codon 129 (ACC-->ATC), both in cervical carcinomas, and the other was in codon 127 (GGG-->GAG) in an endometrial carcinoma. There was one non-sense mutation, in codon 50 (CGA-->TGA), in an endometrial carcinoma. The remaining two were silent somatic cell mutations, both in cervical carcinomas, resulting in no amino acid change. These observations suggest that inactivation of the p16 gene, either by homologous deletion, mutation or loss of expression, occurs in a subset of uterine tumours.

Animals↗
PubMed1999

Relationship between multicentric occurrence of hepatocellular carcinoma and histology of noncancerous hepatic tissue in patients with chronic hepatitis C.

The relationship between multicentric occurrence of hepatocellular carcinoma (HCC) and the histology of noncancerous hepatic tissue was investigated in 252 patients infected with hepatitis C virus (HCV) and surgically treated for HCC. One type of multicentric HCC had at least one tumor consisting of well-differentiated HCC, together with moderately or poorly differentiated HCC located in a separate region. The other type had an area of well-differentiated component around HCC with less differentiation in all occurrences. Noncancerous hepatic tissues were assessed using a histologic activity index score. Serum alanine aminotransferase (ALT) activity, the concentration of type 4 collagen, the grading score (severity of active hepatitis), and the staging score (degree of fibrosis) were significantly higher in patients with multicentric HCCs than in those without them. Platelet count was significantly lower in patients with multicentric HCCs. The prevalence of multicentric HCCs increased as the grading score and staging score increased. On univariate analysis, a low platelet count and high grading and staging scores were risk factors for multicentric HCCs. A high ALT activity and a high concentration of type 4 collagen tended to be risk factors. On multivariate analysis, high grading score and high staging score were independent risk factors. These findings indicate that active hepatitis and extensive fibrosis are responsible for the development of multicentric HCCs. Measurement of platelet count, ALT activity, and the concentration of type 4 collagen, and histologic assessment of noncancerous hepatic tissue provide information useful for estimation of the potential for multicentric carcinogenesis.

Alanine Transaminase↗
PubMed1999

Effects of continuous hepatitis with persistent hepatitis C viremia on outcome after resection of hepatocellular carcinoma.

The effect of persistent hepatitis C viremia on the outcome after resection of hepatocellular carcinoma (HCC) was investigated in 59 consecutive patients with a single small HCC (< or = 3.0 cm in diameter). The presence of serum hepatitis C virus (HCV) RNA was evaluated using a reverse transcription polymerase chain reaction method as well as a branched DNA probe method. Clinicopathologic findings were compared between patients with and without viremia and the risk factors for poor outcome were evaluated. Hepatitis C virus (HCV) RNA was not detected in the sera from 7 patients (group 1), but was detected in the sera from the other 52 patients (group 2). Alanine aminotransferase (ALT) activity was significantly higher in group 2 than in group 1. The proportion of patients with active hepatitis was significantly higher in group 2. In group 2, new HCC often developed after the operation and four patients died of liver dysfunction. HCV viremia, high ALT activity, high concentration of total bilirubin, and liver cirrhosis were related to recurrence after the operation. Multivariate analysis indicated that HCV viremia and high ALT activity were independent risk factors for recurrence of HCC. Continuous hepatitis with persistent HCV viremia worsened the outcome after the resection of HCC by causing new development of HCC and deterioration of liver function. In patients with HCV-related HCC, but without HCV viremia, satisfactory results can be expected after liver resection.

Aged↗
PubMed1999

Leiomyomas in uterine remnants associated with vaginal agenesis.

A premenopausal woman with vaginal agenesis underwent surgery for leiomyomas in rudimentary uterine horns. Immunohistochemical study of surgical specimens revealed that progesterone receptors are distributed in the nuclei of a majority of the leiomyoma cells and in the nuclei of a minority of the myometrial cells. Estrogen receptors are not detected in the surgical specimens.

Cell Nucleus↗
PubMed1999

A pancreatic anaplastic carcinoma of spindle-cell form.

A 56-yr-old man with complaint of abdominal pain and body weight loss was admitted to our hospital. Contrast-enhanced computed tomography on admission revealed a pancreatic tumor. Contrast-enhanced computed tomography 1 m.o. after admission revealed rapid growth of this tumor. We performed exploratory laparotomy with only a needle biopsy of the unresectable tumor because of extensive spread, including liver metastases. Further histological and immunohistochemical examination revealed that both the pancreatic tumor and the hepatic metastases featured malignant spindle-shaped cells. Despite radiotherapy, the patient died 40 d after laparotomy.

Biopsy, Needle↗
PubMed1999

[Resected case of synchronous double cancer of lung and ovarium].

A 45-year-old woman was admitted to our department for a tumor shadow in the right lung on chest rentogenogram and chest CT. Detailed examination led to the diagnosis of simultaneous lung cancer and ovarian cancer. No abnormality was found in the liver. Serum AFP level was 113.8 ng/ml preoperatively, but deceased upper lobectomy of the right lung to 11.4 ng/ml on the 15th day postoperatively. Immunohistochemical study revealed positive staining of carcinoma cells with anti AFP serum.

Adenocarcinoma↗
PubMed1999

[A case report of hepatocellular carcinoma with hepatic and portal venous tumor thrombus and multiple intrahepatic metastasis who survived over 1 year after the operation with combined locoregional chemotherapy].

Hepatocellular carcinoma (HCC) with vascular invasion and/or intrahepatic metastasis (IM) has a poor prognosis, so advanced HCC may be considered as a contraindication for hepatectomy. We experienced a case of HCC with hepatic venous and portal venous tumor thrombus and multiple IM who survived over 1 year after the operation with combined locoregional chemotherapy. (Case): A 67-year-old male patient was diagnosed with HCC with extracapsular invasion after transarterial embolization (TAE). CT scan revealed the HCC had a right portal venous tumor thrombus and multiple IM. Posterior lobectomy and thrombectomy of hepatic venous and portal venous tumor thrombus and placement of portal venous catheter ware performed. From the first day after operation the patient received continuous intravenous and intraportal 5-FU for 3 weeks. At the first month after operation, TAE and PEIT were given against residual IM. After discharge the patient received hepatic arterial infusion chemotherapy (MTX/CDDP/5-FU/Leucovorin). Fourteen months after operation, the patient is surviving in good physical condition.

Aged↗
PubMed1999

Increased expression of COX-2 in nontumor liver tissue is associated with shorter disease-free survival in patients with hepatocellular carcinoma.

Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in a variety of human malignancies including hepatocellular carcinoma (HCC), but little is known about the prognostic value of COX-2 in HCC or its associated nontumor liver tissue. We examined the expression of COX-2 protein by immunohistochemistry in 53 patients with HCCs whose corresponding nontumor tissues were hepatitis C virus-related chronic hepatitis (n = 21) and cirrhosis (n = 32). Samples of nine histologically normal livers and eight precancerous dysplasias were also analyzed. The level of COX-2 increased from normal liver to chronic hepatitis to cirrhosis. The majority of cirrhotic livers (81%) displayed marked COX-2 expression. In dysplasias, COX-2 expression was mainly moderate or strong (88%). In HCC, 17% of samples displayed a high COX-2 expression, and 37% of samples expressed COX-2 at a moderate level. Concordant results were obtained with reverse transcription-PCR and Western blot analyses. Clinicopathological survey indicated a significant correlation between COX-2 expression and differentiated carcinoma (P = 0.019). Although there was no correlation between COX-2 expression in HCC and prognosis, a striking difference was found between COX-2 expression in nontumor tissue and shorter disease-free survival (P = 0.0132). Moreover, high COX-2 expression in nontumor tissue was significantly correlated with the presence of active inflammation (P < 0.0001). The present findings suggest that COX-2 expression in nontumor tissue may play a positive role in relapse of HCC after surgery.

Blotting, Western↗
PubMed1999

Successful treatment using peroral itraconazole in a patient with acute promyelocytic leukemia complicated with splenic candidiasis.

A 57-year-old female with acute promyelocytic leukemia was admitted to our hospital. The PML-RAR alpha fusion transcript was reverse transcription polymerase chain reaction. Complete remission was achieved with intensive induction chemotherapy. Then a high fever unresponsive to antibiotics with increased C-reactive protein continued. Abdominal computed tomography revealed multiple low-density lesions in the spleen. Splenic candidiasis was suspected and peroral treatment with itraconazole (200 mg/day) was begun. After the fungal infection was confirmed to be inactive, splenectomy was performed. The splenic tissue showed multiple white or yellow nodules and methenamine silver stain revealed fungal hyphae characteristic to Candida. There was no evidence of relapse of Candida infection. She has been in complete remission for these two years and free of fungal infection. It is indicated from our case that splenic candidiasis in patients with acute myeloid leukemia can be successfully treated with oral administration of itraconazole and subsequent splenectomy, when it is confined in the spleen.

Antifungal Agents↗
PubMed1999

Hybridization effectiveness of a two-step versus a three-step smear layer removing adhesive system examined correlatively by TEM and AFM.

PURPOSE: The objectives of this study were (1) to compare the hybridization effectiveness of two adhesive systems that are applied in respectively three and two steps, and (2) to determine the best resin-dentin interface preparation technique for atomic force microscopy (AFM). MATERIALS AND METHODS: The resin-dentin interface produced by the three-step OptiBond Dual-Cure (Kerr) and its simplified two-step successor OptiBond Solo (Kerr) was ultramorphologically examined using transmission electron microscopy (TEM) and AFM. Four different methods were used to prepare interface specimens for AFM: (1) polishing to a 0.1-micron finish with a silicon oxide suspension, (2) polishing to a 0.05-micron finish with an aluminum oxide suspension, (3) argon-ion etching, and (4) sectioning with a diamond knife. RESULTS: Both TEM and AFM demonstrated that some collapse of the exposed collagen fibril network, due to gentle postconditioning air-drying of the dentin surface, may not have been totally recovered through hybridization by the two-step adhesive formulation as opposed to the three-step precursor. From the four interface preparation methods, only diamond-knife sectioning revealed sufficient ultramorphologic detail and high resolution that can capitalize on the high resolution offered by AFM. CONCLUSION: First, the findings suggest that simplifying the application procedure of adhesives by combining the primer and adhesive resin into a single application step may reduce hybridization effectiveness. Future research should confirm this effect for other two- versus three-step adhesive systems. Second, diamond-knife sectioning should be used for future topographic imaging and physicomechanical testing of resin-dentin interfaces by AFM.

Bisphenol A-Glycidyl Methacrylate↗