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Biomedical subjects

K Nakano

Publications and source records attributed to K Nakano.

At least 73 records · Page 4Linked to original sources
PubMed2001

Surgical treatment of patients with T2 gallbladder carcinoma invading the subserosal layer.

BACKGROUND: Because T2 carcinoma of the gallbladder that invades perimuscular connective tissue without extension beyond serosa or into the liver has a hope for longterm survival, we attempted to clarify significant prognostic factors with respect to tumor- and surgery-related variables. STUDY DESIGN: Of 65 patients with gallbladder carcinoma who had undergone surgical resection from 1983 to 1999, 28 had T2 carcinoma histologically proved. The significance of variables for survival was examined by the Kaplan-Meier method and log-rank test followed by multivariate analyses using Cox's proportional hazard model. RESULTS: There were 17 patients with stage II carcinoma (T2 N0 M0), 6 with stage III (T2 N1 M0), and 5 with stage IVB. Lymph node metastasis was present in 11 patients (39%) and it reached to the peripancreatic head region (N2) in 5 of them. Lymphatic, venous, and perineural invasions were found in 68%, 57%, and 43%, respectively. With respect to tumor factors, the absence of perineural invasion (Odds ratio [OR] 16.77, 95% confidence interval [CI] 2.17-129.94, p = 0.0069), absence of lymph node metastasis (OR 15.00, 95% CI 2.08-108.33, p = 0.0073), and stage II (II versus III and IVB, OR 15.00, 95% CI 2.08-108.33, p = 0.0073) were significant factors related to good postoperative survival in the multivariate analysis. Surgical procedure (radical resection versus cholecystectomy, OR 4.31, 95% CI 1.34-13.82, p = 0.0142) and surgical margin (OR 7.41, 95% CI 2.19-25.13, p = 0.0013) were significant factors in the univariate analysis. Cancer-free surgical margins provided a significantly better survival (5-year survival rate, 62%); none with cancer-positive surgical margins survived for more than 27 months. In the multivariate analysis, surgical procedure was significant (OR 25.49, 95% CI 1.62-400.72, p = 0.021). Radical surgery, including extended cholecystectomy (resection of the gallbladder together with the gallbladder bed of the liver) and anatomic resection of liver segment 5 and of the lower part of segment 4, gave a significantly better 5-year survival rate than cholecystectomy (59% versus 17%). The 5-year survival rate after radical resection in patients with stage II was 75%; that in patients with stage III and IVB was 33%. CONCLUSIONS: Results suggest that radical surgery is the treatment of choice for patients with T2 carcinoma of the gallbladder. The presence of lymph node metastasis, perineural invasion, or both suggests the necessity of additional treatment after radical surgery.

Antineoplastic Agents↗
PubMed2001

PUMA, a novel proapoptotic gene, is induced by p53.

The p53 tumor-suppressor protein functions as a transcriptional activator, and several p53-inducible genes that play a role in the induction of apoptosis in response to p53 have been described. We have identified a novel gene named PUMA (p53 upregulated modulator of apoptosis) as a target for activation by p53. This gene encodes two BH3 domain-containing proteins (PUMA-alpha and PUMA-beta) that are induced in cells following p53 activation. PUMA-alpha and PUMA-beta show similar activities; they bind to Bcl-2, localize to the mitochondria to induce cytochrome c release, and activate the rapid induction of programmed cell death. Antisense inhibition of PUMA expression reduced the apoptotic response to p53, and PUMA is likely to play a role in mediating p53-induced cell death through the cytochrome c/Apaf-1-dependent pathway.

Alternative Splicing↗
PubMed2001

Quantitation of epidermal growth factor receptor gene amplification by competitive polymerase chain reaction in pre-malignant and malignant oral epithelial lesions.

Abnormal amplification of epidermal growth factor receptor (EGFR) gene has been reported widely in various human tumors. However, the status of amplification of this gene in the process of carcinogenesis is not clearly defined. We used competitive polymerase chain reaction (PCR) to study whether EGFR gene is amplified and the degree of amplification in pre-malignant and malignant oral epithelial lesions, and also examined the relationship between EGFR gene aberration and the development of squamous cell carcinoma (SCC). Genomic DNA was extracted from paraffin sections of 17 cases of oral epithelial dysplasia (ED), four cases of carcinoma in situ (CIS), and 20 cases of untreated primary SCC. The extracted DNA was subjected to competitive PCR to amplify EGFR gene. Amplification of the EGFR gene was observed in three cases (17%) of ED, one case of CIS and four cases (20%) of SCC. In cases showing EGFR gene amplification, the degree of amplification was low in ED and CIS cases, whereas it was extremely high in SCC cases. These results suggest that amplification of EGFR gene occurs in the relatively early stage of the development of oral SCC. However, a high level of EGFR gene accumulation probably plays an important role in the progression to invasive cancer.

Carcinoma in Situ↗
PubMed2001

Purification and identification of major soluble 40-kDa antigenic protein from Entamoeba histolytica: its application for serodiagnosis of asymptomatic amebiasis.

One of the major soluble antigenic proteins of Entamoeba histolytica was purified to homogeneity and identified on a molecular basis. Its recombinant protein was expressed in Escherichia coli as a fusion protein with Shistosoma japonicum glutathione S-transferase. Apparent molecular weight of the purified antigenic protein was estimated to be 40-kDa and molecular-based analysis indicated that the purified protein was NADP+-dependent alcohol dehydrogenase (EhADH1). The application of the purified protein for the serodiagnosis of amebiasis was evaluated using an enzyme-linked immunosorbent assay applied to sera obtained from patients with amebiasis and healthy human controls. The purified protein was well recognized by the sera from asymptomatic amebiasis humans (22/22, 100%), whereas, it was less recognized by the sera from symptomatic amebiasis patients (5/16, 31%) with amebic colitis or liver abscess. To confirm the antigenicity of EhADH1, the recombinant glutathione S-transferase-EhADH1 fusion protein was also evaluated by the enzyme-linked immunosorbent assay using the same sera. The recombinant protein was also recognized by the sera from asymptomatic amebiasis humans (14/22, 64%) and less recognized by the sera from symptomatic amebiasis patients (2/16, 13%). These results suggest that the purified protein is applicable antigen for serodiagnostic screening of asymptomatic amebiasis humans.

Animals↗
PubMed2001

Which is a less invasive pancreatic head resection: PD, PPPD, or DPPHR?

Less invasive pancreatic head resection, such as pylorus preserving pancreatoduodenectomy (PPPD) and duodenum preserving pancreatic head resection (DPPHR) has been introduced for the treatment of pancreatoduodenal lesions, especially for benign conditions, in consideration of postoperative quality of life. Surgical stress and exocrine and endocrine function of the residual pancreas were examined in 44 patients with PPPD, 10 with conventional pancreatoduodenectomy (PD) and six with DPPHR. Clinical findings including serum levels of C reactive protein (CRP), fasting blood sugar, a 120-min value of the 75-g oral glucose tolerance test (OGTT), N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and volume of postoperative pancreatic juice drainage were compared among the three different variants of pancreatectomy. Operation time and operative blood loss in PD were largest of the three, followed by PPPD and DPPHR. Postoperative elevation of serum CRP on postoperative day (POD) 2 or 3 was similar among the three different types of operation. Fasting blood sugar concentrations were not different among the three groups at short- and long-term after the operation, while the 120-min value of the GTT showed a marked elevation at long-term only after PPPD. The volume of pancreatic juice drainage increased up to POD 4 and became constant thereafter. The total amount of pancreatic juice drainage from POD 4 to 13 was smallest in PD (637 ml) followed by PPPD (1,255 ml) and DPPHR (1,431 ml). The BT-PABA value declined after PD (-20.3%, P = 0.0437) and PPPD (-20.2%, P = 0.0239) at short term, but not after DPPHR (8.2%). These findings suggest that the early impairment of the pancreatic exocrine function after PD and PPPD but not after DPPHR may indicate that the invasiveness of pancreatic head resection to the pancreatic functions is greater in PD and PPPD than in DPPHR.

4-Aminobenzoic Acid↗
PubMed2001

Biochemical and genetic characterization of serologically untypable Streptococcus mutans strains isolated from patients with bacteremia.

Four out of 522 streptococcal isolates from the peripheral blood of patients with bacteremia exhibited typical properties of Streptococcus mutans in terms of sucrose-dependent adhesion, expression of glucosyltransferases, fermentation profiles of sugars, the presence of surface protein antigen, and DNA-DNA hybridization. Two strains were determined as serotype f and e by immunodiffusion, whereas the other two isolates did not react with the specific antiserum to S. mutans serotype c. e. or f of the eight different serotypes of mutans streptococci. The latter two untypable isolates, however, expressed a new antigenic determinant that was different from serotype c/e/f specificity as revealed by immunodiffusion. Analysis of the cell wall polysaccharides revealed very low contents of glucose in the untypable isolates. Furthermore, Southern blot analysis demonstrated that the untypable strains lacked at least one gene corresponding to a glucose-adding enzyme. These results indicate that the serologically untypable nature is due to the loss of glucosidic residue from the serotype-specific polysaccharide antigens of S. mutans.

Antigens, Bacterial↗
PubMed2001

Identification and functional analysis of the gene for type I myosin in fission yeast.

BACKGROUND: Type I myosin is highly conserved among eukaryotes, and apparently plays important roles in a number of cellular processes. In the budding yeast, two myosin I species have been identified and their role in F-actin assembly has been inferred. RESULTS: We cloned the fission yeast myo1 gene, which apparently encoded a myosin I protein. Disruption of myo1 was not lethal, but it caused growth retardation at high and low temperatures, sensitivity to a high concentration of KCl, and aberrance in cell morphology associated with an abnormal distribution of F-actin patches. An abnormal deposition of cell wall materials was also seen. Homothallic myo1Delta cells could mate, but heterothallic myo1Delta cells were poor in conjugation. Myo1p was necessary for the encapsulation of spores. The tail domain of Myo1p was pivotal for its function. Calmodulin could bind to Myo1p through the IQ domain at the neck. CONCLUSIONS: Myo1p appears to control the redistribution of F-actin patches during the cell cycle. Loss of Myo1p function is likely to slow down the actin assembly/disassembly process, which results in a failure of the actin cycle to catch up with other events in both the mitotic and meiotic cell cycles, including extension of the conjugation tubes.

Actins↗
PubMed2001

Characterization of GTPase-activating proteins for the function of the Rho-family small GTPases in the fission yeast Schizosaccharomyces pombe.

BACKGROUND: The small GTPase Rho1 has been shown to regulate the organization of the actin cytoskeleton and formation of the cell wall in the fission yeast Schizosaccharomyces pombe. Activity of Rho1 must be precisely regulated in vivo, since both increases and decreases in its activity affect cell growth and shape. Thus, it is important to clarify the mechanism by which the activity of Rho1 is regulated in vivo. RESULTS: Seven genes encoding putative GAPs, GTPase-activating proteins, for the function of the Rho-family proteins were isolated from S. pombe. After disruption of these genes, rga1+ was found to play important roles in cell growth and morphogenesis. In rga1 null cells, delocalized F-actin patches and extraordinary thickening of the cell wall and the septum were observed. On the other hand, over-expression of Rga1 produced shrunken or dumpy cells. The phenotype of the rga1 null cells or the Rga1-over-expressing cells was similar to that of cells containing abnormally high or low Rho1 activity, respectively. Moreover, direct association of Rga1 with Rho1 was shown. Rga1 was localized to the cell ends and septum where Rho1 is known to function. CONCLUSIONS: In S. pombe, Rga1 is involved in the F-actin patch localization, cell morphogenesis, regulation of septation, and cell wall synthesis, probably functioning as a GAP for the function of Rho1.

Actins↗
PubMed2001

Characteristics of breathing abnormality in Leigh and its overlap syndromes.

In this report we describe the respiratory patterns of six patients with Leigh syndrome, including two individual cases with accompanying clinical phenotypes of Alpers disease and mitochondrial encephalopathy with ragged red fibers. In five cases where sleep apnea was monitored, each one showed isolated or post-sigh central apnea, hiccup, apneusis-like breathing and obstructive apnea in various combinations. The remaining patient with Alpers/Leigh overlap syndrome showed an apneusis-like pattern of dyspnea. The sleep structure was examined in three patients. Two patients with brainstem lesions showed a decrease in the deep sleep stages and an absence of REM sleep. Medullary lesions were found in four patients by magnetic resonance imaging or at autopsy and involved predominantly the dorsal respiratory group (DRG) of medullary neurons. The role of DRG lesions in the pathophysiology of respiratory symptoms in Leigh syndrome is discussed.

Brain↗
PubMed2001

D-bifunctional protein deficiency with fetal ascites, polyhydramnios, and contractures of hands and toes.

Fetal abnormalities including chylous ascites, polyhydramnios, claw hands, and hammer toes were identified in an infant who had a missense mutation R106P and a 52bp deletion in the gene for a peroxisomal beta-oxidation enzyme, D-3-hydroxyacyl-CoA dehydratase/D-3-hydroxyacyl-CoA dehydrogenase, D-bifunctional protein. The patient had psychomotor retardation and craniofacial dysmorphism and died at 7 months of age. The patient had atypical fetal manifestations of this enzyme deficiency.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

A morphologic study of Carpentier-Edwards pericardial xenografts in the mitral position exhibiting primary tissue failure in adults in comparison with Ionescu-Shiley pericardial xenografts.

OBJECTIVE: We sought to investigate the durability and mechanism of the Carpentier-Edwards pericardial xenograft in the mitral position in comparison with that of the Ionescu-Shiley pericardial xenograft. METHODS: A total of 284 patients who received the Ionescu-Shiley pericardial xenograft in the mitral position between 1980 and 1984 and 84 patients who received the Carpentier-Edwards pericardial xenograft in the mitral position between 1984 and 1999 were included in the study. The freedom from reoperation rates for both graft types were determined. For morphologic study, the pathologic findings of 23 valves of 123 explanted Ionescu-Shiley pericardial xenografts with structural valve deterioration, nonstructural valve deterioration, or both were determined and compared with those of 20 explanted Carpentier-Edwards pericardial xenografts with structural valve deterioration, nonstructural valve deterioration, or both. Each pathologic finding was graded and assigned a score. Both types were matched for age at reoperation (50-75 years) and duration of valve function (8-11 years). RESULTS: Freedom from reoperation caused by structural valve deterioration, nonstructural valve deterioration, or both was significantly better for Carpentier-Edwards pericardial xenografts than for Ionescu-Shiley pericardial xenografts at 8 years after the operation (Carpentier-Edwards pericardial xenografts: 91.3% vs Ionescu-Shiley pericardial xenografts: 71.9%, P =.0061), but it was similar for both types at 12 years (Carpentier-Edwards pericardial xenografts: 43.6% vs Ionescu-Shiley pericardial xenografts: 43.6%, P =.2865). No severe leaflet tears were seen among Carpentier-Edwards pericardial xenografts. The mean area percentage of tissue overgrowth was 15.3% in Carpentier-Edwards pericardial xenografts and 3.4% in Ionescu-Shiley pericardial xenografts (P =.0001). The mean calcification area percentage was 13.6% in Carpentier-Edwards pericardial xenografts and 31.5% in Ionescu-Shiley pericardial xenografts (P =.0001). CONCLUSIONS: Tissue overgrowth on the atrial surface, ventricular surface, or both was the cause of structural valve deterioration, nonstructural valve deterioration, or both of Carpentier-Edwards pericardial xenografts in adults. This was different from Ionescu-Shiley pericardial xenograft failure, which resulted from severe calcification and leaflet tears. Organized thrombi on cusps, in addition to valve design, may have contributed to such tissue overgrowth on Carpentier-Edwards pericardial xenografts.

Adolescent↗
PubMed2001

Ultrasonic irradiation for blue-green algae bloom control.

A novel application of ultrasonic irradiation for rapid control of blue-green algae (BGA) bloom was investigated. Potassium iodide (KI) experiments demonstrated that frequency and input power are the major factors that affect the ultrasonic irradiation intensity. Short exposure (3 s) to ultrasonic irradiation (120 W input power, 28 kHz) effectively settled naturally growing BGA suspension. Electron microscopy reconfirmed that sedimentation was caused by the disruption and collapse of gas vacuoles after ultrasonic exposure. Moreover, even after 5 min of exposure to ultrasonic irradiation (1200 W input power, 28 kHz) the microcystin concentration in BGA suspensions did not increase. For the same input power (120 W), a lower frequency (28 kHz) was found to be more effective in decreasing the photosynthetic activity of BGA than a higher frequency (100 kHz). The sonicated cells did not proliferate when they were cultured in conditions that simulated the bottom of water bodies (i.e. with limited light (400 lx) or no light and non-aerated or aerated (1 l min-1)). Furthermore, ultrasonic irradiation did not only collapse gas vacuoles and precipitate BGA, but may have also inflicted damage on the photosynthetic system of the BGA.

Cell Culture Techniques↗
PubMed2001

Interactions among a fimbrin, a capping protein, and an actin-depolymerizing factor in organization of the fission yeast actin cytoskeleton.

We report studies of the fission yeast fimbrin-like protein Fim1, which contains two EF-hand domains and two actin-binding domains (ABD1 and ABD2). Fim1 is a component of both F-actin patches and the F-actin ring, but not of F-actin cables. Fim1 cross-links F-actin in vitro, but a Fim1 protein lacking either EF-hand domains (Fim1A12) or both the EF-hand domains and ABD1 (Fim1A2) has no actin cross-linking activity. Overexpression of Fim1 induced the formation of F-actin patches throughout the cell cortex, whereas the F-actin patches disappear in cells overexpressing Fim1A12 or Fim1A2. Thus, the actin cross-linking activity of Fim1 is probably important for the formation of F-actin patches. The overexpression of Fim1 also excluded the actin-depolymerizing factor Adf1 from the F-actin patches and inhibited the turnover of actin in these structures. Thus, Fim1 may function in stabilizing the F-actin patches. We also isolated the gene encoding Acp1, a subunit of the heterodimeric F-actin capping protein. fim1 acp1 double null cells showed more severe defects in the organization of the actin cytoskeleton than those seen in each single mutant. Thus, Fim1 and Acp1 may function in a similar manner in the organization of the actin cytoskeleton. Finally, genetic studies suggested that Fim1 may function in cytokinesis in cooperation with Cdc15 (PSTPIP) and Rng2 (IQGAP), respectively.

Actin Depolymerizing Factors↗
PubMed2001

Tas-301, a new synthetic inhibitor of neointimal thickening after balloon injury, inhibits calcium-dependent signal transduction and cytoskeletal reorganization.

We previously demonstrated that a recently synthesized drug, TAS-301 [3-bis(4-methoxyphenyl)methylene-2-indolinone], inhibited neointimal thickening after single-balloon injury to the rat common carotid artery by inhibiting both the migration and proliferation processes of vascular smooth muscle cells (VSMCs). The purpose of this current study was to elucidate the possible mechanism of action for its inhibition of the migration process of VSMCs. We also determined the efficacy of TAS-301 on second neointimal formation 14 days after a double-balloon injury to the rat common carotid artery. Neointimal thickening, 14 days after second balloon injury, was reduced by the oral administration of TAS-301 in a dose-dependent manner. In in vitro assays using rat VSMCs, Western blot analysis showed that TAS-301 inhibited platelet-derived growth factor (PDGF)-induced tyrosine phosphorylation of both focal adhesion kinase and paxillin. Tyrosine phosphorylation of these proteins depended on the increment of intracellular calcium concentration ([Ca2+]i). The PDGF-induced elevation of [Ca2+]i and activation of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) were also inhibited by TAS-301. Additionally, TAS-301 at 10 micromol/l reduced the extent of F-actin stress fiber depolymerization observed in response to PDGF. These results indicate that TAS-301 reduced the intimal thickening after denudation to a pre-existing lesion to the same extent as it reduced that after a single-balloon injury to the normal artery. Furthermore, the results of our in vitro experiments suggest that antimigratory mechanisms of TAS-301 that contribute to preventing the intimal thickening might be mediated by drug inhibition of Ca2+ -dependent signal molecules and the following cytoskeletal depolymerization.

Animals↗
PubMed2001

Contractile ring formation in Xenopus egg and fission yeast.

How actin filaments (F-actin) and myosin II (myosin) assemble to form the contractile ring was investigated with fission yeast and Xenopus egg. In fission yeast cells, an aster-like structure composed of F-actin cables is formed at the medial cortex of the cell during prophase to metaphase, and a single F-actin cable(s) extends from this structure, which seems to be a structural basis of the contractile ring. In early mitosis, myosin localizes as dots in the medial cortex independently of F-actin. Then they fuse with each other and are packed into a thin contractile ring. At the growing ends of the cleavage furrow of Xenopus eggs, F-actin at first assembles to form patches. Next they fuse with each other to form short F-actin bundles. The short bundles then form long bundles. Myosin seems to be transported by the cortical movement to the growing end and assembles there as spots earlier than F-actin. Actin polymerization into the patches is likely to occur after accumulation of myosin. The myosin spots and the F-actin patches are simultaneously reorganized to form the contractile ring bundles. The idea that a Ca signal triggers cleavage furrow formation was tested with Xenopus eggs during the first cleavage. We could not detect any Ca signals such as a Ca wave, Ca puffs or even Ca blips at the growing end of the cleavage furrow. Furthermore, cleavages are not affected by Ca-chelators injected into the eggs at concentrations sufficient to suppress the Ca waves. Thus we conclude that formation of the contractile ring is not induced by a Ca signal at the growing end of the cleavage furrow.

Actins↗
PubMed2001

[Histamine produced by macrophage and T lymphocyte: a new type of signal transducer].

Macrophages (M phi) produce histamine (Hm) when activated by bacterial endotoxin (LPS) through induced histidine decarboxylase (HDC). Among the cytokines tested, GM-CSF or IL-3 specifically augmented the LPS-dependent HDC induction by M phi. Hm formed by M phi regulates synthesis of cytokines such as IL-1, IL-6, G-CSF and M-CSF by the cells per se and may modulate immune reactions and division and differentiation of various hematopoietic cells. Kupffer cells, M phi-like cells in the liver, also synthesize Hm in mice injected with hepatotoxins such as tetradecanoylphorbol acetate or LPS. Hm thus produced by Kupffer cells may participate in the regeneration of the injured liver through induction of hepatocyte growth factor. Concanavalin A (Con A) enhanced Hm formation by T lymphocytes. GM-CSF or IL-3 also enhanced the Hm synthesis by CD4+ and CD8+ T cells. Hm formed by T cells regulates immune reactions such as lymphocyte blastogenesis. In animals infected with gram(-) bacteria Hm is produced by the M phi-T cell system and may regulate immune competence to the bacteria. In addition, Hm may act as a signal transducer between the peripheral immune system and hypothalamus-pituitary-adrenal system, leading to GC secretion, in order to prevent occurrence of tissue injury caused by excess immune reactions.

Animals↗
PubMed2001

Effects of antimuscarinic drugs on both urinary frequency and cognitive impairment in conscious, nonrestrained rats.

Recent studies indicate a risk of learning and memory impairments when patients with senile dementia are treated with antimuscarinic drugs. In this study, we compared the effectiveness of propiverine hydrochloride (propiverine) and oxybutynin chloride (oxybutynin) on the increased urinary frequency and cognitive impairment induced by nucleus basalis magnocellularis (nBM) lesioning in conscious and nonrestrained rats. For examination of bladder function, nBM-lesioned rats were given total parenteral nutrition regimens for 8 days. Propiverine administered orally at 0.3, 3 and 30 mg/kg on the postoperative day 7 significantly lessened the increase in the frequency of voiding caused by the nBM lesion, whereas oxybutynin administration did not show any improvement at 0.1 or 1 mg/kg but did so at 10 mg/kg. To examine the memory impairment, we trained nBM-lesioned rats in an 8-arm radial maze task for 20 days and then evaluated the effectiveness of oral drug administration on 19th and 20th radial maze performance. The higher rate of errors caused by nBM lesioning was significantly aggravated by oxybutynin at 30 and 100 mg/kg. Propiverine showed slight aggravation of errors, but with no statistical significance at any dose, 30, 100 or 300 mg/kg. These results suggest that propiverine has comparatively less effect on the cognitive impairment than oxybutynin.

Administration, Oral↗