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Biomedical subjects

T Yoshikawa

Publications and source records attributed to T Yoshikawa.

At least 289 records · Page 16Linked to original sources
PubMed1999

Extended resection for intrahepatic cholangiocarcinoma in Japan.

To elucidate surgical outcome after extended surgery for intrahepatic cholangiocarcinoma (ICC), we retrospectively allocated 83 patients who had undergone resection to a standard surgery group (n = 56), in which the patients had undergone hepatectomy alone or hepatectomy with bile duct resection, and an extended surgery group (n = 27), in which the patients had undergone the standard operation combined with vessel resection and/or pancreatectomy. The incidence of mass-forming plus periductal-infiltrating type lesions (P = 0. 0129), lymph node metastasis (P = 0.0005), noncurative resection (P < 0.0001), mortality within 30 days and within 1 year after surgery (P = 0.0392, P = 0.0010), local recurrence (P = 0.0439), and peritoneal disseminated recurrence (P = 0.0241) was significantly higher in the extended surgery group than in the standard surgery group. The 5-year survival rate was significantly higher in the standard surgery group (30%) than in the extended surgery group (10%; P = 0.0061). The mortality rate within 1 year after extended surgery was significantly higher in the patients with infiltrating-spread type tumors than in the patients with non-infiltrating spread type tumors (P = 0.0032), and long-term (5-year) survival in the extended surgery group was significantly lower in the patients with infiltrating-spread type tumors than in the patients with non-infiltrating spread type tumors (P = 0.0253). We conclude that extended surgery does not improve the curative resection rate or the surgical outcome of ICC, and that extended surgery is not indicated for patients with infiltrating-spread type tumors.

Adult↗
PubMed1999

The significance of hepatectomy for primary intrahepatic stones.

The objective of this study was to evaluate the significance of performing hepatectomy for primary intrahepatic stones. Observations on the morphology of the bile ducts, histopathological findings of the excised liver, and treatment results were reviewed in 29 of 35 patients with primary intrahepatic stones. The remaining 6 patients (17.1%) were excluded because they had intrahepatic cholangiocarcinoma. The subjects were classified into two groups according to the morphological characteristics of the bile ducts; one group comprised 25 patients having strictures in the central bile duct, and another group comprised 4 patients having no biliary stricture, but a localized dilatation in the distal bile duct. Calcium bilirubinate stones were found in all the patients with a biliary stricture, whereas cholesterol stones were found in those without a biliary stricture. Hepatectomy was performed in 25 of the 29 patients (86.2%), the results of which were excellent. In fact, during the past 10 years, no postoperative complications have occurred, nor have there been any retained or recurrent stones. Moreover, the postoperative hospitalization period was as short as 15.3 days. The findings of this study indicate that hepatectomy allows treatment for primary intrahepatic stones to be completed within a short period of time without incurring serious postoperative complications, and serves as a useful prophylactic technique for recurrent stones.

Bile Duct Diseases↗
PubMed1999

Neurohumoral activations in congestive heart failure: correlations with cardiac function, heart rate variability, and baroreceptor sensitivity.

BACKGROUND: The clinical significance of the determination of heart rate variability and baroreceptor sensitivity relating to cardiac function and neurohumoral factors remains to be established. METHODS AND RESULTS: We investigated the relation between conventional clinical variables and frequency domain analysis of heart rate variability and baroreceptor sensitivity in 146 patients with heart failure. Cardiac function including left ventricular ejection fraction, left ventricular dimensions, and left atrial size was different by the plasma atrial natriuretic peptide level but not by the norepinephrine level. The total power and low-frequency power were correlated with plasma norepinephrine, whereas baroreceptor sensitivity was correlated with plasma atrial natriuretic peptide. None of the frequency domain variables and baroreceptor sensitivity was correlated with cardiac function. There was a positive correlation between the low-frequency power and baroreceptor sensitivity. CONCLUSIONS: Heart rate variability and baroreceptor sensitivity, which reflect autonomic regulation, may be an indicator independent from cardiac function in patients with heart failure.

Atrial Natriuretic Factor↗
PubMed1999

Intraoperative evaluation of the depth of invasion of gallbladder cancer.

BACKGROUND: It is sometimes very difficult to diagnose the depth of invasion of gallbladder cancer preoperatively. Therefore, we investigated intraoperative examinations to diagnose the depth of invasion. METHODS: A total of 104 patients were included in this study. The relation between macroscopic morphology and the depth of invasion and evaluation of the depth of invasion by intraoperative ultrasonography and frozen section examination were investigated. RESULTS: In all cases of a pedunculated type and a subpedunculated type with thin base, invasion remained within the mucosa. In other types, the depth of invasion was various. The accuracy of diagnosing the depth of invasion by intraoperative ultrasonography and frozen section examination was 73.9% and 85.7%, respectively. CONCLUSIONS: The cancer classified as a pedunculated type or a subpedunculated type with thin base can be diagnosed to remain within the mucosa. In other types, intraoperative ultrasonography and frozen section examination are useful in the diagnosis of the depth of invasion.

Adult↗
PubMed1999

Effect of intrinsic wetness and regional difference on dentin bond strength.

OBJECTIVES: The aim of this investigation was to determine the influence of intrinsic wetness on regional bond strengths of adhesive resins to dentin. METHODS: Human caries-free third molars were randomly divided into three groups for bonding: Group 1--no pulpal pressure; Group 2--pulpal pressure of 15 cm H2O; and Group 3--dentin dried overnight in a desiccator. Clearfil Liner Bond II (Kuraray) or One Step (Bisco) adhesive resins systems were applied to the flat dentin surfaces and the teeth were restored with APX resin composite (Kuraray). After 24 h in water at 37 degrees C, the specimens were sectioned into 0.7 mm thick slabs and divided into three regional subgroups according to the remaining dentin thickness and visual criteria: pulp horn, center, and periphery. The slabs were then trimmed for the micro-tensile bond test and subjected to a tensile force and crosshead of 1 mm/min. The data were analyzed with ANOVA and Fisher's PLSD test at a confidence level of 95%. The fracture modes were determined under a scanning electron microscope (JXA-840, JEOL, Japan). RESULTS: No significant regional difference was observed for the Group 1 and 2 specimens restored with Clearfil Liner Bond II (p > 0.05). However, bond strengths significantly decreased at the pulp horn region of the Group 1 and 2 specimens restored with One Step (p > 0.01). All bond strengths of Group 3 decreased significantly and regional differences were not evident (p > 0.05). SIGNIFICANCE: The dentin adhesive system should be chosen according to the substrate and region to be bonded, since bond strengths can vary according to the intrinsic wetness, region, and the adhesive system.

Dental Bonding↗
PubMed1999

Characterization of novel FcepsilonRII/CD23 isoforms lacking the transmembrane (TM) segment in human cell lines.

Human FcepsilonRII/CD23 is an approximately 45 kDa type II transmembrane glycoprotein belonging to the C-type animal-lectin family, and has two isoforms (a and b) that only differ in their intracytoplasmic tails. We previously found that in several human and mouse cell lines there were two additional CD23 transcripts (a' and b') lacking the exon 3 that encodes the entire transmembrane segment and a part of cytoplasmic tails. In this study, we analyzed the putative CD23a' and CD23b' products at protein levels and characterized with rabbit polyclonal antibodies against novel amino-acid sequences of the putative CD23a' and CD23b' molecules (anti-CD23a' Ab, anti-CD23b' Ab). Western blots in COS cells transfected with CD23a' or CD23b' cDNA as well as in vitro translation assays showed that the a' and b' CD23 transcripts were translated to about 40 kDa molecules. These 40 kDa molecules were also recognized by a polyclonal antibody against 25 kDa soluble fragment of human CD23. We also found that human cells having mRNAs for CD23a' and CD23b' expressed protein products recognized specifically by anti-CD23a' or anti-CD23b' Ab, respectively. In addition, the CD23a' and CD23b' molecules in transfected COS cells were resistant to Endo H(f) and PNGase F, although these truncated forms as well as the membrane-associated forms had an asparagine residue responsible for the N-linked glycosylation. Taken together, our results show that the a' and b' CD23 transcripts are expressed and translated in human lymphoid cells and that their translated products are retained in the cytoplasm where they might play an unique regulatory role in the expression of the full-length CD23 on the cell surface.

Amino Acid Sequence↗
PubMed1999

Accelerated recovery from cyclophosphamide-induced leukopenia in mice administered a Japanese ethical herbal drug, Hochu-ekki-to.

The effect of a Japanese ethical herbal drug, Hochu-ekki-to (HOT), on recovery from leukopenia induced by cyclophosphamide (CY) was investigated. Daily oral administration of 1000 mg/kg HOT into CY-treated mice significantly prevented decrease of leukocyte numbers in the peripheral blood and accelerated recovery from leukopenia. Ginsenoside Rgl extracted from Ginseng radix, a major herb of HOT, was one of the active ingredients. HOT increased numbers of neutrophils and monocytes in the peripheral blood compared with CY-treated control. Moreover, HOT augmented the resistance against Pseudomonas aeruginosa infection. The number of colony-forming units in the spleen (CFU-S) also increased in HOT-treated mice. The frequencies of IL-3-, GM-CSF- and IFN-gamma-producing cells increased in the spleen, bone marrow, liver and IEL on HOT treatment, and HOT clearly augmented the expressions of IL-3, GM-CSF and IFN-gamma mRNA in the spleen, bone marrow, liver and IEL except IL-3 and IFN-gamma mRNA in the IEL. These results suggest that HOT enhances the production of hematopoietic lymphokines, stimulates the proliferation of hematopoietic progenitor cells and consequently accelerates recovery from leukopenia in CY-treated mice. Additionally, IFN-gamma which HOT-augmented the production may contribute the protective effect against the bacterial infection by activating of phagocyte cells.

Animals↗
PubMed1999

Systematic screening of chromosome 18 for loss of heterozygosity in esophageal squamous cell carcinoma.

Esophageal cancer ranks among the 10 most common cancers in the world, and is almost uniformly fatal. The genetic events leading to the development of esophageal carcinoma are not well established. To identify genomic regions involved in esophageal carcinogenesis, we performed a systematic screening for loss of heterozygosity (LOH) in 24 samples of squamous cell carcinomas, initially focusing the analysis on chromosome 18. Thirteen short tandem repeat markers spanning 18p and 18q were used. We found a broad peak of LOH spanning 18p11.2 and 18q21.1 with the most frequent LOH (72%) at D18S978 on 18q12.2, which coincides with a known fragile site FRA18A. This region is 4 cM proximal to known tumor suppressor genes and therefore suggests the possible existence of a yet undiscovered tumor suppressor gene.

Alleles↗
PubMed1999

Helicobacter pylori water extract induces interleukin-8 production by gastric epithelial cells.

In Helicobacter pylori-associated gastric mucosal injury, interleukin (IL) -8, a potent leukocyte chemoattractant, is produced by epithelial cells infected by H. pylori and directs neutrophils to the gastric mucosa. According to previous studies, the IL-8 production requires direct contact between the bacteria and epithelial cells. The aims of the present study were to determine whether an H. pylori water extract (HPE) induces IL-8 production by gastric epithelial cells and to characterize IL-8-inducing substances in HPE. Extracts were prepared from a standard strain and from strains obtained from patients with gastric ulcers. After addition of HPE to MKN 45 cells, a gastric cancer cell line, IL-8 in supernatants and IL-8 mRNA were measured by immunoassay and reverse transcription-polymerase chain reaction, respectively. For characterization, active fractions obtained by gel filtration of standard-strain HPE were treated by heating or trypsinization. To study the signal pathway leading to IL-8 production, inhibitors for protein kinase A (PKA), protein kinase C (PKC), or protein tyrosine kinase (PTK) were incubated with MKN45 cells before HPE stimulation. HPE from the standard strain and one of these clinical strains induced IL-8 production. Lipopolysaccharide or cagA in the strains showed no correlation with IL-8 concentration. Standard-strain HPE induced IL-8 mRNA expression in MKN 45 cells. Gel filtration localized activity to a low-molecular-weight fraction of about 7 kDa, which was resistant to heat and trypsin digestion. PKC inhibitors significantly blocked HPE-induced IL-8 production by MKN 45 cells; however, the PKA inhibitor or PTK inhibitors showed a partial inhibitory effect. HPE contains a nonprotein substance of low molecular weight that is responsible for IL-8 induction in gastric epithelial cells. This induction is mainly dependent on the activation of PKC but partially also dependent on PKA or PTK.

Cells, Cultured↗
PubMed1999

Thymidine phosphorylase/platelet-derived endothelial cell growth factor is upregulated in advanced solid types of gastric cancer.

Previous studies demonstrated that the immunohistochemical expression of thymidine phosphorylase (dThdPase) was related with distant metastasis and disease progression. In this study we investigated the production of dThdPase/platelet-derived endothelial cell growth factor in gastric cancer quantitatively. In a total of 75 tumour tissues and 60 normal gastric mucosa specimens, dThdPase protein concentrations were determined by ELISA. The amount of dThdPase was significantly higher in the tumour tissue than in the normal tissue. Intratumoural dThdPase concentrations were significantly higher in Borrmann types I and II macroscopically, in poorly differentiated and solid type histologically, in the medullary type of the tumour stroma, and in the tumour-invading serosa. In the medullary type of the amount of tumour stroma, protein levels of dThdPase were positively correlated with the vertical diameter of the tumour (r = 0.580, P = 0.019). By immunohistochemical study, dThdPase expression on tumour cells was observed in all seven specimens with high dThdPase protein levels, but not in all 14 cases with low dThdPase protein levels (P < 0.05). In summary, these data indicated that dThdPase is up-regulated in advanced solid types of gastric cancer, suggesting that dThdPase production in carcinoma cells might be induced by the microenvironment.

Analysis of Variance↗
PubMed1999

Effect of vitamin E in gastric mucosal injury induced by ischaemia-reperfusion in nitric oxide-depleted rats.

BACKGROUND: Neutrophil infiltration and lipid peroxide accumulation are involved in reperfusion-induced gastric mucosal injury in nitric oxide-depleted rats. AIM: To assess the effect of vitamin E on this injury. METHODS: After ischaemia-reperfusion, the total area of erosions, lipid peroxide contents in gastric mucosa, and gastric neutrophil accumulation were compared between nitric oxide-depleted rats with deficient, normal, and increased vitamin E intake over 8 weeks. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in gastric mucosa as indices of lipid peroxidation and neutrophil infiltration. RESULTS: The total area of erosions was significantly increased in the vitamin E-deficient group compared with the sufficient-intake and vitamin-supplemented groups. Both thiobarbituric acid-reactive substances and myeloperoxidase activity also were significantly increased in the vitamin E-deficient group compared with others. The total area of erosions closely paralleled the increases in both thiobarbituric acid-reactive substances and myeloperoxidase activity. CONCLUSION: These results indicate that the inhibition of lipid peroxidation and interference with neutrophil infiltration by vitamin E may be responsible for its cytoprotective effect in ischaemia-reperfusion.

Animals↗
PubMed1999

Effect of shear stress and a stable prostaglandin I2 analogue on adhesive interactions of colon cancer cells and endothelial cells.

In the process of cancer metastasis, adhesion between cancer cells and endothelial cells is an important early step. In the present study, the effects of shear stress and the adhesion molecules responsible for cancer cell interactions with endothelial cells were investigated in a system similar to in vivo microcirculation. The effect of prostaglandin I2 (PGI2) also was determined. Human colon cancer cell line Colo 201 and human umbilical vein endothelial cells (HUVEC) were used. After HUVEC on a glass slide were incubated with IL-1beta for 4 h, cancer cells in suspension were perfused on HUVEC at wall shear stresses of 5-40 microN/cm2. Experiments were videotaped, and the number of adherent cells were counted. Additionally, the effects of anti-sialyl Lewis a (SLea) MoAb, anti-E-selectin MoAb, and a PGI2 analogue were investigated. Expression of adhesion molecules on cancer cells and HUVEC was assessed using flow cytometry and enzyme immunoassay, respectively. Few cancer cells adhered to HUVEC without IL-1beta; however, many cancer cells adhered to IL-1beta-stimulated HUVEC at low shear stress (5-20 microN/cm2). Cancer cells did not migrate beneath HUVEC. The increased adhesion was inhibited by anti-E-selectin MoAb, anti-SLea MoAb, and a PGI2 analogue. In addition, the PGI2 analogue decreased the surface expression of SLea on Colo 201 cells. These results suggest that Colo 201 cells adhere to IL-1beta-stimulated endothelial cells via SLea and E-selectin under low flow conditions; PGI2 analogues may protect against metastasis by inhibiting cancer cell-endothelial cell interactions.

Adult↗
PubMed1999

Ultrastructural localization of E-cadherin and alpha-/beta-catenin in adenoid cystic carcinoma.

AIMS: To investigate the disturbance of intercellular adhesion in adenoid cystic carcinoma (ACC), we examined the ultrastructural localization of E-cadherin (E-cad), alpha-catenin (alpha-cat) and beta-catenin (beta-cat) in ACC, and compared it with that in the normal labial gland. METHODS AND RESULTS: Using immuno-electron microscopy, in the normal labial gland, E-cad was found to be uniformly distributed along the plasmalemma, where cells were in close contact with each other, with junctional complexes, desmosomes and interdigitations; expression of alpha-cat and beta-cat was also detected. In ACC, which was classified into tubular, cribriform and trabecular types, E-cad expression seemed not to be uniform, but was observed to be along the plasmalemma where cell-to-cell contact was made. On the other hand, expression of alpha-cat or beta-cat was uneven in the trabecular-type cells which were very slender and grew in an infiltrative scattered pattern into the extracellular matrix; that was absent in the cribriform-type cells which made contact with each other mostly at the tip of the cytoplasmic processes. CONCLUSION: These findings suggest that the neoplastic cells of ACC express E-cad for use in intercellular adhesion, but the cadherin-catenin complex might not operate properly, which is the cause of neoplastic cell dissociation, followed by invasion and metastasis.

Adult↗
PubMed1999

Epithelioid hemangioendothelioma with marked liver deformity and secondary Budd-Chiari syndrome: pathological and radiological correlation.

A case of malignant epithelioid hemangioendothelioma of the liver in a 48-year-old woman with severe portal hypertension and marked deformity of the liver is presented. This woman had a history of mild liver dysfunction since the age of 30 years, and abdominal distention, esophageal varices, splenomegaly and ascites since October 1996. Imaging examinations revealed liver deformity with severe atrophy of the left lobe and the anterior segment of the right lobe. Celiac arteriography showed narrowing and upward deviation of the proper hepatic artery, and occlusion of the left and right anterior hepatic arteries. Since March 1997, hepatic venography showed stenosis in the right hepatic vein truncus. Budd-Chiari syndrome was clinically diagnosed. She died in June 1997. The autopsy disclosed massive tumor embolism in the left and right anterior portal branches, few in the hepatic artery, and occlusion of the left and right anterior hepatic arteries. The extensive tumor embolism resulted in portal hypertension, and atrophy of the left lobe. The anterior segment of the right lobe was probably caused by the occlusion of both the hepatic arteries and the portal veins. The posterior segment of the right lobe, without massive tumor embolism in its portal branch, appeared hypertrophic.

Budd-Chiari Syndrome↗
PubMed1999

Colony stimulating factor-inducing activity of hesperidin.

To evaluate immunomodulating activities of bioflavones, colony-stimulating factor (CSF)-inducing activity of two dihydroflavones, three flavones and three flavonols were tested. These samples were suspended in saline and injected intraperitoneally (i.p.) into mice at a dose of 1 mg 6 h before bleeding. All compounds carrying the glucosyl-rhamnose moiety showed potent activity. Among them, hesperidin exhibited the strongest activity. Serum CSF production in mice injected with 1 mg hesperidin reached a peak at 9 h later. The activity of hesperidin was dose-dependent at a range of 0.3 to 20 mg/mouse.

Adjuvants, Immunologic↗
PubMed1999

Ginkgo biloba leaf extract: review of biological actions and clinical applications.

The number of studies on Ginkgo biloba leaves is rapidly increasing. A variety of effects of Ginkgo biloba leaf extract (GBLE) have been identified. GBLE contains many different flavone glycosides and terpenoides. GBLE has an antioxidant action as a free radical scavenger, a relaxing effect on vascular walls, an antagonistic action on platelet-activating factor, an improving effect on blood flow or microcirculation, and a stimulating effect on neurotransmitters. Besides a direct scavenging action on active oxygen species, GBLE exerts an anti-inflammatory effect on inflammatory cells by suppressing the production of active oxygen and nitrogen species. GBLE inhibited the increase in the products of the oxidative decomposition low-density lipoprotein (LDL), reduced the cell death in various types of neuropathy, and prevented the oxidative damage to mitochondria, suggesting that GBLE exhibits beneficial effects on neuron degenerative diseases by preventing chronic oxidative damage. The study using a model of ischemia-reperfusion injury has also demonstrated the protective effect of GBLE on cardiac muscle and its antioxidative action in vivo. Favorable results have been obtained in double-blind, placebo-controlled, comparative trials of patients with memory disorders, obstructive arteriosclerosis, and dementia. We review the recent studies on GBLE with respect to its various pharmacological actions, such as a scavenging activity on free radicals and an inhibitory action on lipid peroxidation. GBLE shows a very strong scavenging action on free radicals, and is thus considered to be useful for the treatment of diseases related to the production of free radicals, such as ischemic heart disease, cerebral infarction, chronic inflammation, and aging.

Animals↗