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Biomedical subjects

Y Shimizu

Publications and source records attributed to Y Shimizu.

At least 343 records · Page 19Linked to original sources
PubMed1998

Lymph node status assessment for gastric carcinoma: is the number of metastatic lymph nodes really practical as a parameter for N categories in the TNM Classification? Tumor Node Metastasis.

BACKGROUND AND OBJECTIVES: The anatomical extent of nodal metastasis has been replaced by the number of metastatic nodes as a key indicator of prognosis (pN categories) in the fifth edition of Tumor Node Metastasis Classification for gastric carcinoma by the International Union Against Cancer. The rate of metastatic nodes among all the nodes harvested is also a good prognostic factor. The object of this study is to evaluate which of the three parameters for the assessment of nodal status is the most appropriate for use in the stage classification. METHODS: Retrospective survival analyses were performed in 656 consecutive patients with advanced gastric carcinoma who underwent D2 lymphadenectomy and for whom histopathologic data of more than 20 lymph nodes were available. RESULTS: Although all three systems served well to classify the patients into distinct groups in terms of survival curves, stratification by the number of metastatic nodes was vulnerable to stage migration because of differences in the number of lymph nodes harvested. Such stage migration was not evident for the other two parameters. CONCLUSIONS: Lymph node metastatic rate can be recommended as an internationally applicable parameter for lymph node involvement of gastric carcinoma.

Adult↗
PubMed1998

Role of hydrophobic amino acids in gurmarin, a sweetness-suppressing polypeptide.

The sweetness-suppressing polypeptide gurmarin isolated from Gymnema sylvestre consists of 35 amino acid residues and contains three intramolecular disulfide bonds. Nuclear magnetic resonance analysis showed that the hydrophobic side chains of Tyr-13, Tyr-14, Trp-28, and Trp-29 in gurmarin are oriented outwardly. Together with the hydrophobic side chains of Leu-9, Ile-11, and Pro-12, they form a hydrophobic cluster, and therefore these hydrophobic groups are assumed to act as the site for interaction with the receptor protein. To examine the roles of these hydrophobic amino acids, they were replaced by Gly. The resulting [Gly13,14,28,29] gurmarin and [Gly9,11,13,14,28,29]-gurmarin did not suppress the responses to sucrose, glucose, fructose, or Gly. This result strongly suggests that these hydrophobic amino acids are involved in the interaction with the receptor protein.

Amino Acid Sequence↗
PubMed1998

Synthesis, characterization, and sweetness-suppressing activities of gurmarin analogues missing one disulfide bond.

The sweetness-suppressing polypeptide gurmarin isolated from Gymnema sylvestre consists of 35 amino acid residues and includes three intramolecular disulfide bonds. The roles of the three disulfide bonds were investigated by replacing each with two alanine residues by solid-phase synthesis. Nine analogues of [Ala3,18]gurmarin, [Ala10,23]gurmarin, and [Ala17,33]-gurmarin were obtained. Three analogues had native disulfide bonds, while the other six had non-native disulfide bonds. The three analogues with native disulfide bonds suppressed the response to sucrose, but not those to glucose, fructose, saccharin, or glycine in rats. In contrast, the six analogues with non-native disulfide bonds did not suppress the responses to any of these sweeteners. These results suggest that the native disulfide bonds of gurmarin are necessary for interaction with the receptor protein, and that the sucrose-specific receptor site is present in rats.

Amino Acid Sequence↗
PubMed1998

Efficacy and safety of early coronary stenting for unstable angina.

To determine the efficacy and safety of early coronary stenting for unstable angina, we studied 91 consecutive patients with unstable angina. Thirty-one patients underwent stenting 72 h or more after admission, and another 60 patients underwent stenting within 72 h of admission. The clinical and angiographic follow-up had been done for 6 mo. There were no differences between the baseline clinical and angiographic characteristics of both groups. The maximum balloon pressure was higher (14.1 +/- 1.2 vs. 12.6 +/- 0.9, P < 0.01) and the hospital stay was shorter (9.7 +/- 2.7 vs. 18.7 +/- 5.8 d, P < 0.0001) in the early stenting group. These two groups were similar in the clinical success rate (90.0% vs. 93.5%), without any abrupt closure, subacute thrombosis, death, myocardial infarction, or coronary bypass surgery. These findings indicate that early stenting can be useful in patients with unstable angina.

Aged↗
PubMed1998

Evaluation of a novel alginate gel dressing: cytotoxicity to fibroblasts in vitro and foreign-body reaction in pig skin in vivo.

Calcium alginate dressings have beneficial effects on wound healing by providing a moist wound environment. However, cytotoxicity and the nonbiodegradable nature of calcium alginate dressings induce unresolved chronic foreign-body reaction. In this study, a novel freeze-dried alginate gel dressing (AGA-100) low in calcium ions was evaluated for cytotoxicity to L929 cells in vitro and in full-thickness pig wounds in vivo. Cytotoxicity testing on L929 cells showed the cytocompatibility of AGA-100 extracts, while extracts from Kaltostat, a well-established alginate dressing, induced cytopathic effects. In an in vivo study using pigskin, AGA-100, Kaltostat, and gauze were applied on 1-in-diameter circular full-thickness wounds on the back of pigs and the time course of wound closure was evaluated. Kaltostat and gauze dressings were used as controls. For histologic evaluation, wound tissue was harvested on day 18. AGA-100-treated wounds showed rapid wound closure compared to control wounds on day 15. Foreign-body reaction was marked in Kaltostat- and gauze-treated wounds, and differed significantly from AGA-100-treated wounds. Based on these data, AGA-100 could reduce the cytotoxicity to fibroblasts and foreign-body reaction that have been observed with currently available calcium alginate dressings; it was also found to be useful as an alginate dressing.

Alginates↗
PubMed1998

A new drug delivery system with controlled release of antibiotic only in the presence of infection.

An ideal drug delivery system (DDS) releases an appropriate drug at specific locations and times. We tried to create a new antibiotic delivery system that releases gentamicin only when wounds are infected by Pseudomonas aeruginosa (P.A.). Exudate from the dorsal pouch of rats infected with P.A. showed significantly higher hydrolytic activity-thrombin-like activity-toward Boc-Val-Pro-Arg-MCA than exudate from noninfected wounds. We therefore constructed a device for controlled release of an antimicrobial drug triggered by thrombin-like activity. Briefly, gentamicin was bound to a polyvinyl alcohol derivative (PVA) hydrogel through a newly developed peptide linker cleavable by the proteinase, PVA-(linker)-gentamicin. In vitro experiments showed that proteinases from wounds infected with P.A. cleaved the linker and gentamicin was released while the exudate from noninfected wounds had no hydrolytic activity toward the linker. This device shows potential as an occlusive dressing with an effective antibiotic delivery system for treating infected wounds.

Amino Acid Sequence↗
PubMed1998

Toward the development of a universal grading system for ovarian epithelial carcinoma. I. Prognostic significance of histopathologic features--problems involved in the architectural grading system.

OBJECTIVE: Because there is no universally accepted grading system for ovarian epithelial carcinoma, we attempted to compare the prognostic utility of the individual components used in some systems--both architectural and cytologic features, as well as mitotic activity and histologic tumor type--to determine which of these components fit best with survival. METHODS: We studied 461 patients with invasive ovarian carcinoma who had uniform treatment, complete clinical data including staging and follow-up, and slides available for review. Each tumor was assigned a histologic subtype, architectural grade (based on whether the predominant pattern was glandular, papillary or solid), nuclear grade, mitotic count, and FIGO grade (based on the system for endometrial carcinoma). These features were compared with each other and with tumor stage and survival. RESULTS: The architectural grade, nuclear grade, and mitotic count were independent variables both in stage I/II and stage III/IV disease. Each of them correlated with survival for most combinations of histologic type and stage. By multivariate analysis, in stage I/II cancer, nuclear grade and architectural grade were significantly correlated with survival, mitotic count showed only a trend, and FIGO grade did not correlate. In stage III/IV disease, nuclear grade, architectural grade 3, and mitotic count were significant, and FIGO grade was not. CONCLUSION: The new architectural grading system proposed worked better than the FIGO system in this study. Furthermore, it could be applied to all histologic subtypes of carcinoma. The nuclear grade and mitotic count were also independent of each other, correlated with survival, and could be utilized for all histologic types. These data support the development of a grading system which combines these architectural, nuclear, and mitotic features and can be applied regardless of the histologic type of carcinoma, modeled after the Nottingham system for grading of breast carcinoma.

Carcinoma↗
PubMed1998

Analysis of immunosuppressive proteins in serum of liver-transplanted rats by using an anti-LSF-1 affinity column.

Liver suppressor factor one (LSF-1) is a 40-kDa immunosuppressive protein in the serum of rats 60 days after orthotopic liver transplantation (OLT) between the nonrejector combination of DA donors into PVG recipients. In the present study, the purification of proteins from rat OLT serum taken 60 days after transplantation was performed by affinity chromatography using the anti-LSF-1 polyclonal antibody (pAb). The assessment of column eluates using anti-LSF-1 and OLT serum was studied using rat heart and liver transplantation models. Rejection was not suppressed by the administration of OLT serum in heart or liver allografts. However, heart allografts treated with peak eluates (450 micrograms single shot im, dissolved in Intralipos) taken from the affinity OLT serum survived significantly longer than untreated rats (median = 36.5 days; n = 7 vs 6.5 days; n = 5, respectively, P = 0.011). The same treatment with anti-LSF-1 column eluates also prolonged liver allografts significantly (>200 days) than those in either the untreated group (median = 11 days; n = 7) or those which received only Intralipos (median = 10.5 days; n = 5, P = 0.019). Subsequent analysis of the N-terminal sequences of some of the proteins which were eluted from the affinity column revealed that the homology of a 30-kDa protein was identical to hemoglobin alpha-chain, a 59-kDa protein to granulocyte inhibitory factor, a 70-kDa and a 90-kDa to albumin and its precursor, respectively. Although the specific immunosuppressive component has not been isolated, our results suggested that the anti-LSF-1 column can extract immunosuppressive moiety of LSF-1 from OLT serum.

Animals↗
PubMed1998

Lactoferrin and interleukin-6 interaction in amniotic infection.

Lactoferrin (Lf) has been found in most biological fluids including amniotic fluid and cervical mucoids in pregnant women, and released from neutrophils in response to the inflammation. As Lf possesses antimicrobial properties, it is widely considered to be an important component of the host defence against microbial infections. It is known that premature labor is caused by amniotic infection with the increase of prostaglandin production. High concentration of the inflammatory cytokines: interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) in the amniotic fluid has been known. However, changes of Lf in amniotic fluid with infection has not been reported. In the present study, Lf concentrations in amniotic fluid were measured under the intra-uterine infections state and the biological significance of Lf was investigated. The effects of Lf on the IL-6 and IL-6mRNA production in cultured amnion cells were also investigated. The concentrations of Lf and IL-6 in amniotic fluid with CAM were 8.76 +/- 0.65 micrograms/ml and 6.92 +/- 4.88 ng/ml (n = 28) respectively and both were significantly higher (p < 0.01) than those without CAM [0.86 +/- 0.81 microgram/ml and 0.34 +/- 0.25 ng/ml (n = 31)]. Significant positive correlation (r = 0.91, p < 0.01) between Lf and IL-6 levels in amniotic fluid was found. IL-6 production induced by lipopolysaccharide (LPS) (100 ng/ml) in cultured amnion cells was significantly inhibited (p < 0.05) under the physiological concentration of Lf in amnion. Total RNA was extracted from the amniotic cells by guianizine solution. RT-PCR procedure and product analysis were performed from one microgram aliquote of total RNA. beta-actin was used as an international standard and c-DNA samples were followed by 30 cycles of PCR. RT-PCR product of IL-6 mRNA was detected by Southern hybridization. Expression of IL-6 mRNA was inhibited by the addition of Lf. From the results, the possibility that Lf might suppress amniotic IL-6 production under the condition of amniotic infection is suggested. It is also suggested that Lf might act as self defence mechanism from intra-uterine infection.

Amnion↗
PubMed1998

Inhibitory effects of 1,25(OH)2D3 on membrane-associated and cytosolic casein kinase activity in MC3T3-E1 osteoblast-like cells.

The secretion of phosphorylated matrix proteins is high in osteoblasts. Phosphorylation of these proteins may be catalyzed by casein kinases (CK), and CK may play an important role in the site of bone mineralization. In this study, we examined the effects of 1, 25(OH)2D3 on CK activities in MC3T3-E1 osteoblast-like cells. Different concentrations (ranging from 10(-7) to 10(-11)M) of 1, 25(OH)2D3 were included in a culture medium. After incubation for various lengths of time, MC3T3-E1 cells were homogenized and segregated into cytosolic (c) and microsomal (m) fractions. To measure CK activity, each fraction was used as an enzyme source to phosphorylate casein. MC3T3-E1 cells showed the highest cCK activity after incubation for 21 days, and showed the highest mCK activity after incubation for 14 days. 1,25(OH)2D3 inhibited mCK activity at the early stage of culture, but inhibited cCK activity at the late stage of culture. In contrast, 1,25(OH)2D3 had a slight stimulatory effect on CK activity in the culture medium of MC3T3-E1 cells. Our data suggest that cCK and mCK may play different roles in the function of osteoblasts, and 1,25(OH)2D3 regulates intracellular and extracellular casein kinase activities related to the function of osteoblasts.

3T3 Cells↗
PubMed1998

Effect of interleukin-8 on production of tumor-associated substances and autocrine growth of human liver and pancreatic cancer cells.

We have previously reported that human liver cancer cell lines produce interleukin-8 (IL-8) at high levels. Those tumor cells appeared to express two kinds of IL-8 receptor on their surface. In order to analyze the role of IL-8 on the biological characteristics of those tumor cells, we suppressed IL-8 production from human liver (HuH-7 and HuCC-T1) and pancreatic cancer cell lines (HuP-T4) by treatment with IL-8 antisense oligonucleotides. Suppression of IL-8 production resulted not only in inhibition of cell growth, but also in an increase in the concentrations of some tumor-associated substances such as carbohydrate antigen 19-9 (CA19-9) in the medium. These data indicate that IL-8 produced by human liver and pancreatic tumors may act as an autocrine growth factor and may control the production of some tumor-associated substances. Furthermore, surface expression of sialyl-Lewis(a), which is a ligand for ELAM-1 on human umbilical vein endothelial cells (HUVEC), HuCC-T1 and HuP-T4 cells was decreased and the attachment of these tumor cells to HUVEC was inhibited by treatment with IL-8 antisense oligonucleotide. Since the soluble form of CA19-9 (sialyl-Lewis(a)) was shown to inhibit the tumor cell binding to HUVEC, the decrease in release of CA19-9 into the medium and increase in the expression of sialyl-Lewis(a) on the cell surface may suggest that IL-8 production from the tumor cells enhances metastatic potential by augmenting the binding activity of the tumor cells to HUVEC. These data demonstrate that a cytokine produced by tumor cells may function as an autocrine growth factor and affect tumor cell dissemination.

Antigens, CD↗
PubMed1998

Multiple sulphatase deficiency and haemophagocytic syndrome.

A 3-year-old boy with multiple sulphatase deficiency, complicated by a haemophagocytic syndrome, recovered with conventional treatment. Haemophagocytic syndrome can be a complication of many disorders including metabolic diseases, frequently triggered by intracellular viral and bacterial infections or even by drug administration.

Child, Preschool↗
PubMed1998

Presacral epidermoid cyst: report of a case.

An asymptomatic tumor in the pelvis was incidentally found by ultrasonography in a 67-year-old woman while being examined after presenting with a common cold. Further examinations revealed a presacral cystic tumor, which measured 10 x 12cm in size. The cyst was thus removed in the normal manner for such cases. The pathological diagnosis was an epidermoid cyst. An analysis of 15 other cases previously reported in the literature indicated that large epidermoid cysts should normally be excised through an abdominal approach alone, provided that the tumor is benign.

Aged↗
PubMed1998

Predictive value of floaters in the diagnosis of posterior vitreous detachment.

PURPOSE: To evaluate Weiss ring and floaters as indexes of posterior vitreous detachment. METHODS: Using biomicroscopy and indirect ophthalmoscopy, we examined the posterior vitreous in 200 consecutive eyes with posterior vitreous detachment. RESULTS: In 200 eyes with posterior vitreous detachment, biomicroscopy disclosed complete, incomplete, and no Weiss ring in 102 (51%), 72 (36%), and 26 (13%) eyes, respectively. Indirect ophthalmoscopy showed the glial ring in 58 (56.9%) and 16 (22.2%) of the eyes, with a complete (102 eyes) and incomplete (72 eyes) Weiss ring, respectively. Although the incidence of floaters was significantly correlated with the presence of the glial ring (P = .0014), 60 (58.8%) and 49 (68.1%) of the eyes with a complete (102 eyes) and incomplete (72 eyes) glial ring, respectively, had no floaters. CONCLUSION: Detecting the detached posterior vitreous cortex by biomicroscopy is essential regardless of the presence of Weiss ring or floaters.

Aged↗
PubMed1998

Segments I and IV resection as a new approach for hepatic hilar cholangiocarcinoma.

Major hepatic resection for biliary tract carcinoma with obstructive jaundice has been reported on as bringing about high surgical morbidity and mortality rates. It has been also revealed that the extent of hepatic resection is closely associated with the occurrence of postoperative complications. Therefore, hepatic resection, limited as much as possible to what is necessary for curative resection, should be performed according to cancer extent. We performed a new surgical approach in 3 patients with hepatic hilar cholangiocarcinoma that included total resection of hepatic segments I and IV (by Couinaud's classification) and bile duct resection with hepaticojejunostomy of 4 to 6 intrahepatic bile duct stumps. All patients underwent curative surgical resections and were discharged within 6 weeks after surgery, without any serious complications. This limited resection of hepatic segments I and IV could be an effective radical surgical procedure for hepatic hilar cholangiocarcinoma, to avoid the occurrence of postoperative liver failure.

Cholangiocarcinoma↗
PubMed1998

The experimental replacement of a cervical esophageal segment with an artificial prosthesis with the use of collagen matrix and a silicone stent.

OBJECTIVE: Attempts have been made to replace esophageal defects with a variety of artificial materials. However, because of the artificial nature of the materials, problems such as infection, leakage, stricture, or dislocation could not be avoided. Therefore we have designed a new type of artificial esophagus that is gradually replaced by host tissue. METHODS: Our artificial esophagus was a two-layered tube consisting of a collagen sponge matrix and an inner silicone stent. We used it to replace 5 cm esophageal segmental defects in 43 dogs, and the inner silicone stent was removed endoscopically at weekly intervals from 2 to 4 weeks. RESULTS: In the 27 dogs from which the silicone stent was removed at 2 or 3 weeks, constriction of the regenerated esophagus progressed and the dogs became unable to swallow within 6 months. In the 16 dogs from which the silicone stent was removed at 4 weeks, highly regenerated esophageal tissue successfully replaced the defect, leaving no foreign body in the host. Moreover, the regenerated esophagi had stratified flattened epithelia, striated muscle tissue composed of an inner circular and an outer longitudinal muscle layer, and esophageal glands. CONCLUSIONS: Even in mature adult higher mammals, esophageal high-order structures can be regenerated provided that an adequate three-dimensional extracellular structure is put in place for a sufficient period.

Actins↗