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Biomedical subjects

M Kuwahara

Publications and source records attributed to M Kuwahara.

At least 73 records · Page 4Linked to original sources
PubMed2000

Application of artificial dermis graft to correct a depression after tissue resection.

The authors present 7 cases of artificial dermis implantation to correct a depression after tissue resection. Four of the seven cases resulted from resection of a malignant tumor (N = 3) and from a benign subcutaneous tumor (N = 1). The other 3 cases were the result of temporal muscle harvest to reconstruct facial palsy. In 1 patient a mild degree of bone deformity also existed. The pieces of artificial dermis employed varied from 35 x 40 to 40 x 80 mm in size. In 5 patients two sheets were implanted, and in 2 patients three sheets were implanted. In 2 patients the dermis sheets were covered by a pedicled temporal fascial flap with a free split-thickness skin graft because whole skin was resected as a result of a malignant skin tumor. There was no postoperative infection or allergic reaction in any of the patients. In all cases there was no postoperative contracture, and the implanted area was soft. An adequate or acceptable thickness of subcutaneous tissue was obtained. Artificial dermis may be a useful option as implantation material to correct a depression after tissue resection, especially for wide and comparatively shallow depressions.

Aged↗
PubMed2000

An evaluation of hard palate mucosa graft as a lining material in alar reconstruction: a 7-year experience applied to the full-thickness alar defect.

The authors present their experience with 25 hard palate mucosa grafts used as lining material in the reconstruction of full-thickness alar defects. Good "take" was obtained in 22 grafts; the other three grafts incurred necrosis of the overriding skin flaps and postoperative infection. Degree of shrinkage was 11 to 15 percent of grafted size in patients with the type of defect that did not include the alar margin; shrinkage was 26 to 35 percent in patients with the type that included more than 50 percent of the alar margin. In all patients who had a good graft take, the nasal cavities were maintained and there was no nasal obstruction or collapsing during strong breathing. The healing time of the palate donor site varied from 7 days to 5 weeks, depending on the size of the defect. No patients experienced any symptoms at the donor site after healing. The authors concluded that hard palate mucosa can be considered a useful material in alar reconstruction because of the ease in graft harvesting and its support features. When the defect is large enough to involve the total unilateral ala nasi, even though the degree of postoperative shrinkage is comparatively high, hard palate mucosa may be the most suitable material to ensure good take of the graft and less possibility of donor-site morbidity.

Adult↗
PubMed2000

Molecular identification of a human carcinoma-associated glycoprotein antigen recognized by mouse monoclonal antibody FU-MK-1.

Mouse monoclonal antibody FU-MK-1, raised against a human gastric adenocarcinoma, recognizes an antigen (termed MK-1 antigen) present on the majority of carcinomas. The present study aimed to identify the MK-1 molecule and to establish its relationship to other carcinoma antigens. Immunoprecipitation studies of human tumor cell lines revealed that FU-MK-1 recognizes a monomeric membrane glycoprotein with two forms, 40 kDa (major form) and 42 kDa (minor form), and with a molecular mass of 35 kDa following treatment with the N-glycosylation inhibitor tunicamycin. The partial amino acid sequence of a main fragment of the MK-1 molecule obtained by spontaneous cleavage under hypotonic conditions was examined, and the 17 contiguous NH2-terminal amino acids were found to be identical with residues 81-97 of the 314-residue GA733-2 protein [Szala et al.; Proc. Natl. Acad. Sci. USA, 87, 3542-3546 (1990)]. Hence, the GA733-2 cDNA was cloned and the specificity of FU-MK-1 was confirmed using four recombinant forms of the GA733-2 antigen expressed in COS-1 cells. Immunoprecipitation with FU-MK-1 of the cell lysate transfected with the full-length GA733-2 cDNA revealed two bands corresponding to those obtained from the tumor cell lines. FU-MK-1 also precipitated three other recombinant proteins consisting of amino acids 1-265, 1-201, and 1-139 of the GA733-2 protein, respectively. Furthermore, immunoblotting analysis indicated that FU-MK-1 binds to a small fragment (6 kDa) generated from a tumor cell line under hypotonic conditions, suggesting that the FU-MK-1 epitope exists on the distal 6-kDa peptide of the extracellular domain of the GA733-2 molecule. We thus conclude that the MK-1 antigen is the GA733-2 antigen, which is currently being used as a target in clinical trials with monoclonal antibodies.

Amino Acid Sequence↗
PubMed2000

Degradation of bisphenol A by the lignin-degrading enzyme, manganese peroxidase, produced by the white-rot basidiomycete, Pleurotus ostreatus.

Degradation of 2,2-Bis(4-hydroxyphenyl)propane (bisphenol A, BPA), an endocrine-disturbing chemical, by the growing mycelia of the white-rot basidiomycete, Pleurotus ostreatus, was examined. About 80% of BPA initially present decreased in 12 days of culture with this fungus. By in vitro experiments using the lignin-degrading enzyme manganese peroxidase (MnP), BPA was metabolized to phenol, 4-isopropenylphenol, 4-isopropylphenol, and hexestrol. The degradation products of BPA were assumed to be formed by the one-electron oxidation of the substrate.

Air Pollutants, Occupational↗
PubMed2000

Pulmonary microcystic hamartoma in an adult dog.

Microcystic hamartoma was detected as a tumorlike mass in the left caudal lung lobe of a 12-year-old mixed-breed dog. Histologically, the mass was characterized by microcysts of various sizes that mimicked alveoli and were surrounded by thin fibrous septal tissue. However, unlike the adjacent lung parenchyma, bronchial or bronchiolar trees were absent, and the septal vascular channels were extremely underdeveloped. Immunohistochemically, the cells lining the microcysts were consistently positive for cytokeratin but not for vimentin, whereas the septal fibroblast-like cells were negative for cytokeratin and positive for vimentin. Electron microscopy confirmed that the microcysts were lined with a layer of type I and type II mature pneumocytes. This is the first description of the detailed morphologic features of microcystic hamartoma.

Animals↗
PubMed2000

[A case of epithelial cancer of the alveoli which responded favorably to the additional administration of UFT for refractory cancer after administration of carboplatin and docetaxel].

Epithelial cancer of the alveoli is considered to be a pulmonary non-small cell carcinoma which responds poorly to carcinostatics. In one case of epithelial cancer of the alveoli which metastasized to both lungs and caused breathing to deteriorate rapidly, chemotherapy was applied with 500 mg of carboplatin (CBDCA) and 90 mg of docetaxel (TXT). Although the tumor was reduced initially, it was found to have been aggravated again three weeks after the start of the chemotherapy. In the second and third courses of the chemotherapy, CBDCA and TXT were administered in the same dosage as in the initial course, but with the oral administration of UFT (600 mg/day). The results were favorable, as evidenced by the absence of recurring aggravation. Currently, the patient has been followed on an outpatient basis for over six months with the administration of UFT. Good QOL is being maintained without any repeated aggravation of the tumor.

Administration, Oral↗
PubMed2000

Effect of epinephrine and combination treatment of epinephrine and heat on melanoma cell lines. Study of cytotoxicity and kinetics of 72-kD stress protein.

To elucidate the effect of epinephrine and the combination with heat on malignant cells, using two melanoma cell lines, HM6KO and G361, we have examined the cytotoxicity and induction of 72-kD stress protein (HSP72) after the treatments. After epinephrine treatment, in both cell lines, cell survival rates decreased gradually in a concentration-dependent manner. After the combination treatment, cell survival rates decreased more than those when two treatments were done separately. The cytotoxicity of epinephrine was more enhanced in G361 than in HM6KO by heat. After epinephrine treatment, in both cell lines, the level of HSP72 did not elevate. After combination treatment, in HM6KO, the level of HSP72 were higher than those of heat alone. In G361, the kinetics of HSP72 level was similar to that of heat alone. These results suggest that epinephrine has a cytotoxicity to melanoma cells and the cytotoxicity is enhanced by the combination. In addition, it is probable that epinephrine does not have HSP72 inducibility in HM6KO and G361, and the different kinetics of HSP72 between the cell lines in the combination treatment may play an important role to determine the degree of enhancement.

Adrenergic Agonists↗
PubMed1999

Transmembrane helix 5 is critical for the high water permeability of aquaporin.

Aquaporin-2 (AQP2), a vasopressin-regulated water channel, plays a major role in urinary concentration. AQP2 and the major intrinsic protein (MIP) of lens fiber are highly homologous (58% amino acid identity) and share a topology of six transmembrane helices connected by five loops (loops A-E). Despite the similarities of these proteins, however, the water channel activity of AQP2 is much higher than that of MIP. To determine the site responsible for this gain of activity in AQP2, several parts of MIP were replaced with the corresponding parts of AQP2. When expressed in Xenopus oocytes, the osmotic water permeability (P(f)) of MIP and AQP2 was 48 and 245 x 10(-)(4) cm/s, respectively. Substitutions in loops B-D failed to increase P(f), whereas substitution of loop E significantly increased P(f) 1.5-fold. A similar increase in P(f) was observed with the substitution of the front half of loop E. P(f) measurements taken in a yeast vesicle expression system also confirmed that loop E had a complementary effect, whereas loops B-D did not. However, P(f) values of the loop E chimeras were only approximately 30% of that of AQP2. Simultaneous exchanges of loop E and a distal half of transmembrane helix 5 just proximal to loop E increased P(f) to the level of that of AQP2. Replacement of helix 5 alone stimulated P(f) 2.7-fold. Conversely, P(f) was decreased by 73% when helix 5 of AQP2 was replaced with that of MIP. Moreover, P(f) was stimulated 2.6- and 3.3-fold after helix 5 of AQP1 and AQP4 was spliced into MIP, respectively. Our findings suggested that the distal half of helix 5 is necessary for maximum water channel activity in AQP. We speculate that this portion contributes to the formation of the aqueous pore and the determination of the flux rate.

Animals↗
PubMed1999

Extracellular lipid peroxidation of selective white-rot fungus, Ceriporiopsis subvermispora.

Ceriporiopsis subvermispora is capable of decomposing lignin without penetration of enzymes into wood cell walls. To elucidate the mechanism of lignolysis at a site far from enzymes, peroxidation of low molecular mass compounds produced by this fungus was analyzed. C. subvermispora produced free 9,12-octadecadienoic, 9-octadecenoic, 11-octadecenoic, hexadecanoic and octadecanoic acids, predominantly at an early stage of cultivation on wood meal cultures. In prolonged cultivation period after 2 weeks, the amount of intact fatty acids decreased with increasing organic hydroperoxide and TBARS production. These results suggest that lignin degradation by C. subvermispora is related to extracellular lipid peroxidation.

Basidiomycota↗
PubMed1999

Cytosolic calcium changes in a process of platelet adhesion and cohesion on a von Willebrand factor-coated surface under flow conditions.

Recent flow studies indicated that platelets are transiently captured onto and then translocated along the surface through interaction of glycoprotein (GP) Ib with surface-immobilized von Willebrand factor (vWF). During translocation, platelets are assumed to be activated, thereafter becoming firmly adhered and cohered on the surface. In exploring the mechanisms by which platelets become activated during this process, we observed changes in platelet cytosolic calcium concentrations ([Ca(2+)]i) concomitantly with the real-time platelet adhesive and cohesive process on a vWF-coated surface under flow conditions. Reconstituted blood containing platelets loaded with the Ca(2+) indicators Fura Red and Calcium Green-1 was perfused over a vWF-coated glass surface in a flow chamber, and changes in [Ca(2+)]i were evaluated by fluorescence microscopy based on platelet color changes from red (low [Ca(2+)]i) to green (high [Ca(2+)]i) during the platelet adhesive and cohesive process. Under flow conditions with a shear rate of 1,500 s(-1), no change in [Ca(2+)]i was observed during translocation of platelets, but [Ca(2+)]i became elevated apparently after platelets firmly adhered to the surface. Platelets preincubated with anti-GP IIb-IIIa antibody c7E3 showed no firm adhesion and no [Ca(2+)]i elevation. The intracellular Ca(2+) chelator dimethyl BAPTA did not inhibit firm platelet adhesion but completely abolished platelet cohesion. Although both firm adhesion and cohesion of platelets have been thought to require activation of GP IIb-IIIa, our results indicate that [Ca(2+)]i elevation is a downstream phenomenon and not a prerequisite for firm platelet adhesion to a vWF-coated surface. After platelets firmly adhere to the surface, [Ca(2+)]i elevation might occur through the outside-in signaling from GP IIb-IIIa occupied by an adhesive ligand, thereby leading to platelet cohesion on the surface.

Blood Platelets↗
PubMed1999

Real-time analysis of mural thrombus formation in various platelet aggregation disorders: distinct shear-dependent roles of platelet receptors and adhesive proteins under flow.

We evaluated real-time processes of platelet thrombus formation on a collagen surface in a flow chamber with whole blood from patients with various platelet aggregation disorders, such as Bernard-Soulier syndrome (BSS), Glanzmann's thrombasthenia (GTA), type 3 von Willebrand disease (vWD), and congenital afibrinogenemia (Af), who lack platelet glycoprotein (GP) Ib-IX complex, GP IIb-IIIa, von Willebrand factor (vWF), and fibrinogen, respectively. Blood from GTA patients showed impaired thrombus growth but significant initial platelet-surface interaction under all shear conditions tested (50 to 1,500 s(-1)). By contrast, blood from patients with BSS or type 3 vWD showed no platelet-surface interaction under high shear (>/=1, 210 s(-1)) but normal thrombus formation under low shear (</=340 s(-1)). When shear rate was increased stepwise to 1,500 s(-1) during perfusion, the thrombus growth observed in type 3 vWD or BSS under low shear was arrested, whereas that in control blood was sharply accelerated as a function of shear rate. Overall thrombus formation in Af appeared indistinguishable from that of a control under shear rates between 50 and 1,500 s(-1). However, Af thrombi formed under such conditions collapsed immediately when shear rate was further increased to 4,500 s(-1), whereas thrombi of type 3 vWD or BSS formed under low shear were stable even when shear rate was elevated to 9,000 s(-1) during perfusion. These findings suggest that distinct molecular mechanisms underlie the pathologic bleeding in these diseases and point to the distinct roles of two major adhesive proteins, vWF and fibrinogen. In mural thrombus formation under flow conditions, vWF, perhaps mainly through its interaction with GP Ib-IX, acts as an "initiator and promoter," whereas fibrinogen, via its binding to GP IIb-IIIa, acts as a "stabilizer" against heightened shear forces that could lead to peeling off of platelets from the surface.

Blood Coagulation Disorders↗
PubMed1999

Finger bougie method compared with pyloroplasty in the gastric replacement of the esophagus.

To elucidate the necessity of pyloroplasty for the gastric tube through the posterior mediastinum in esophageal surgery, gastric emptying and duodenogastric reflux (DGR) were evaluated in 16 cases undergoing an anterior pylorectomy (group P) and in 16 cases treated by the finger bougie method (group F). First, the obstruction and reflux symptoms were examined based on a patient questionnaire using a brief scoring system. The median value of the symptom score showed the patients in P to have more symptoms than those in F; however, the difference was not significant (8.0 vs 6.0). Secondly, the swallowed Tc O4- (85MBq) was counted using a gamma camera at three sites on the sternal bone in the upright position based on a gastric transit scintigram. Both the descending time of the RI peak and the clearance rates were similar between the two groups. Thirdly, intragastric 24-h pH monitoring was carried out. Antimony pH sensors were anchored 5 and 15cm below the esophagogastrostomy. We could not find any difference between the two groups in both the %time pH > 4 and %time pH > 7. These findings thus revealed no big difference between groups P and F. The finger bougie method to drain the vagotomized posterior mediastinal stomach was found to achieve results similar to conventional pyloroplasty, while it was also simpler and safer.

Adult↗
PubMed1999

Endosonographic study of anal sphincters in patients after surgery for Hirschsprung's disease.

PURPOSE: This study was performed to evaluate the relationship between endosonographic findings of anal sphincters and anorectal function in patients after surgery for Hirschsprung's disease. In addition, whether internal sphincterotomy or sphincterectomy was accomplished was examined in each procedure by anal endosonography. METHODS: Fifteen patients, aged 11 to 20 years, were examined. Nine patients underwent modified Duhamel's operation, three underwent Rehbein's operation with anorectal myectomy, and three underwent modified Martin's operation. All 15 patients were examined by anal endosonography using a sonographic scanner (Aloka SSD 2000) with a 7.5-MHz radial rotating endoprobe, clinical bowel assessment, and manometric study. RESULTS: After the modified Duhamel operation, anal endosonography showed an interruption of the external anal sphincter (EAS) in eight of the nine patients, as a high, mixed, or low echoic lesion in the hyperechoic band correlated to the EAS. The locations of the interruption were wide in patients with mild constipation. An interruption of the internal anal sphincter (IAS) was observed in all nine patients, as a hyperechoic lesion in the hypoechoic band correlated to IAS, which indicated internal sphincterotomy. After Rehbein's operation with anorectal myectomy, an interruption of EAS was observed in all three patients as a high or low echoic lesion in the hyperechoic band. An interruption of IAS was observed in all three patients. After the modified Martin's operation, an interruption of EAS was observed in two of the three patients as a high or low echoic lesion in the hyperechoic band. An interruption of IAS was observed in all three patients. CONCLUSION: Anal endosonography showed detailed distributions of EAS and IAS in patients after surgery for Hirschsprung's disease and complete internal sphincterotomy or sphincterectomy after these operations.

Adolescent↗
PubMed1999

Lignin-degrading enzyme production by Bjerkandera adusta immobilized on polyurethane foam.

Production of the lignin-degrading enzymes lignin peroxidase (Lip), manganese peroxidase (MnP), and laccase (Lac) by the white-rot fungus Bjerkandera adusta was investigated experimentally using polyurethane foam (PUF) as a carrier of immobilized fungal mycelia. An immobilized cell culture with a low-nitrogen medium yielded significantly greater LiP, MnP, and Lac activities in comparison with those obtained in a liquid culture. The maximum activities of the three enzymes were 450, 370, and 100 U/ml, respectively, under the following incubation condition: glucose concentration, 20 g/l; temperature, 30 degrees C; pH 4.5. The activities of MnP and Lac were significantly higher than those reported using other incubation methods. Lignin was degraded to the extent of 40% and its decolorization ratio was about 70% at an incubation time of 40 h using lignin-degrading enzymes from B. adusta. Six different isozymes of MnP were synthesized by B. adusta, two of which exhibited high MnP activity. Our preliminary finding that extracellular enzymes from B. adusta are capable of degrading and decoloring lignin makes these enzymes attractive for further research aimed at their large-scale application in lignin depolymerization, pulp biobleaching, and the degradation of toxic pollutants.

Journal Article↗
PubMed1999

p53, p21(Waf1/Cip1) and cyclin D1 protein expression and prognosis in esophageal cancer.

Recently, various cell cycle regulators have been investigated as biological markers of malignant potential. These regulators might influence the survival rate and the effect of adjuvant therapies. In this study, we analyzed p53, p21(Waf1/Cip1) and cyclin D1 expression in 64 esophageal cancer patients and the relationship between clinicopathologic parameters and patient survival. The positive expression rate was 48.4%, 42.2% and 43.8% in the p53, p21 and cyclin D1 groups respectively. Multivariant analysis revealed that tumor depth, chemotherapy, p53, p21 and cyclin D1 expression showed significant values. p53- and cyclin D1-negative patients had a worse prognosis. p21-positive patients had a better prognosis. In stage 0, I and II patients, there was a significant difference between p53-positive and -negative, p21-positive and -negative, and cyclin D1-positive and -negative groups. In stage III and IV patients, there was no significant difference between any two groups. However, a significant difference was seen in the p21 group: among patients who received adjuvant chemotherapy, the p21-positive group had a 5-year survival rate of 50% compared with 13.4% in the p21-negative group (not significant).

Cyclin D1↗