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Biomedical subjects

K Sakamoto

Publications and source records attributed to K Sakamoto.

At least 91 records · Page 5Linked to original sources
PubMed2001

Laboratory data and treatment outcomes of head and neck tumor patients in the elderly.

OBJECTIVE: To elicit the factors influencing the choice of treatment and the prognosis of elderly patients, we studied the clinical and laboratory data of head and neck tumor patients. The patients were divided into two groups (group A: younger than 75, group B: 75 years of age or older) and the treatment outcomes as well as the features of the laboratory data were analyzed. METHODS: The clinical records of 1350 patients (888 males, 462 females) with head and neck tumors who received their initial treatment at our hospital were reviewed. The collected data including age, the site of the primary lesion, pre-treatment health states, pre-operative laboratory results were examined. According to the treatment policy, we grouped the patients according to whether or not they had received the standard therapy for the disease and then analyzed their treatment outcomes. RESULTS: Standard therapy was not performed in 62 (5.6%) of the 1114 patients in group A and in 43 (18.2%) of the 236 patients in group B. A further analysis performed in group B (elderly patients) revealed that standard therapy was performed in 193 patients, while 43 received non-standard therapy. The prognosis for the non-standard therapy cases was poor. The averages of the laboratory test findings between groups A and B were compared, but no marked differences were observed. However, differences were observed in the ratio of patients whose data were in the normal range between group A and group B. When the laboratory data were compared between the standard and non-standard groups of the elderly, serum albumin and CBC (especially hemoglobin) showed a close relationship to the treatment modality. CONCLUSION: The ratio of patients who did not receive standard therapy was high in the age group of 75 years or older. The prognosis of patients with head and neck tumors is therefore considered to depend on whether or not a patient receives the standard therapy against the disease. The pre-treatment clinical data and the laboratory findings vary markedly among elderly patients 75 years of age or older. Regarding the treatment of head and neck tumors in the elderly, the laboratory data and clinical conditions of each individual patient should be checked carefully and every possible means should be employed in order to allow such patients to receive the standard therapy whenever possible.

Adult↗
PubMed2001

Assessment of coronary flow velocity with transthoracic Doppler echocardiography during dobutamine stress echocardiography.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) in the left anterior descending coronary artery (LAD) during contrast-enhanced dobutamine stress echocardiography (DSE). We also assessed the value of TTDE for detecting stress-induced myocardial ischemia in the LAD territory. BACKGROUND: Noninvasive assessment of both CFV and wall motion during DSE would enhance the diagnostic accuracy of DSE. METHODS: One hundred forty-four consecutive patients underwent CFV recording in the distal LAD by TTDE during contrast-enhanced DSE. Regional wall motion score index (WMSI) in the LAD territory and CFV ratio at peak stress (CFV ratio peak), defined as a ratio of CFV at peak stress to basal CFV, were obtained. RESULTS: Coronary flow velocity was successfully recorded in 129 patients (90%) at baseline and during dobutamine infusion. Mean value of CFV ratio peak was 2.39 +/- 0.83 (range: 0.84 to 4.40). There was good correlation between WMSI at peak stress and CFV ratio peak (r = 0.62, p < 0.001). Coronary flow velocity ratio peak was significantly lower in patients who developed stress-induced wall motion abnormality (WMA) in the LAD territory than it was in those patients without WMA (1.51 +/- 0.51 vs. 2.76 +/- 0.65, p < 0.001). A CFV ratio peak <2.1 had a sensitivity of 92% and a specificity of 86% for detecting the presence of stress-induced WMA. CONCLUSIONS: Assessment of CFV in the distal LAD during DSE is feasible in the majority of cases and provides a CFV ratio for detecting stress-induced myocardial ischemia in the LAD territory.

Adult↗
PubMed2001

Visually based path-planning by Japanese monkeys.

To construct an animal model of strategy formation, we designed a maze path-finding task. First, we asked monkeys to capture a goal in the maze by moving a cursor on the screen. Cursor movement was linked to movements of each wrist. When the animals learned the association between cursor movement and wrist movement, we established a start and a goal in the maze, and asked them to find a path between them. We found that the animals took the shortest pathway, rather than approaching the goal randomly. We further found that the animals adopted a strategy of selecting a fixed intermediate point in the visually presented maze to select one of the shortest pathways, suggesting a visually based path planning. To examine their capacity to use that strategy flexibly, we transformed the task by blocking pathways in the maze, providing a problem to solve. The animals then developed a strategy of solving the problem by planning a novel shortest path from the start to the goal and rerouting the path to bypass the obstacle.

Animals↗
PubMed2001

The expression of chicken NOV, a member of the CCN gene family, in early stage development.

The nephroblastoma overexpressed gene, NOV, is a member of the CCN gene family. We investigated the NOV gene expression pattern in the chicken during early stage embryogenesis. Several embryonic structures showed a distinct expression pattern. The initial expression was detected in Hensen's node (Hamburger and Hamilton stage (HH) 5). The expression was noted in the presumptive notochord and floor plate forming cells. The expression on the left side was more elongated posteriorly, a type of left-right asymmetry. Chicken NOV gene expression in the forming notochord and floor plate was observed until HH 18. The expression was also detected in the ventral area of the mesencephalon and isthmus at HH 14-16.

Journal Article↗
PubMed2001

Effect of diltiazem on cardiac function assessed by echocardiography and neurohumoral factors after reperfused myocardial infarction without congestive heart failure.

The purpose of this study was to examine the effect of diltiazem on cardiac function and neurohumoral factors (BNP, epinephrine, norepinephrine) after reperfused myocardial infarction without congestive heart failure (Killip class I). On the first day after myocardial infarction following reperfusion therapy patients were randomly assigned to diltiazem treatment (group 1, n=33) or no treatment (group 2, n=39). We then performed echocardiographic examinations on the patients and measured heart rate, mean blood pressure and neurohormones (BNP, epinephrine and norepinephrine). Follow-up evaluations of echocardiography were performed at 4 and 12 weeks and of neurohormones at 1 and 4 weeks after acute myocardial infarction. The highest peaks of plasma BNP, epinephrine, and norepinephrine levels were observed before treatment and decreased with time in both groups. After 4 weeks the level of plasma BNP in the diltiazem treatment group was lower than in the no treatment group [55+/-3 pg/mL vs 85+/-5 pg/mL (P < 0.05)]. Other neurohormones did not differ between groups. Fractional shortening (FS) and ejection fraction (EF)improved after myocardial infarction in both groups, but significantly more in the diltiazem group (P < 0.05) after 12 weeks of treatment. Changes in BNP correlated significantly with changes in left ventricular end systolic volumes, FS and EF. In this study, diltiazem significantly improved systolic function and reduced the level of plasma BNP after myocardial infarction, which suggest that diltiazem may have a beneficial effect on myocardial infarction without congestive heart failure.

Aged↗
PubMed2001

Synthesis and evaluation of various layered octacalcium phosphates by wet-chemical processing.

Octacalcium phosphate was synthesized by hydrolysis of alpha-tricalcium phosphate through a wet-chemical processing. Using the same wet-chemical processing in presence of various succinate ions, the preparation of some complexed octacalcium phosphates was attempted. The products were examined by X-ray diffraction method. These complexed octacalcium phosphates intercalated with succinic acid, L-asparatic acid, and methyl succinic acid showed an expanded basal spacing in the octacalcium phosphate unit cell dimensions. The microstructure was observed by scanning and transmission electron microscopy.

Journal Article↗
PubMed2001

Growth factors, extracellular matrix components and cell adhesion molecules Warthin's tumor.

We studied expressions of various growth factors, their receptors, cell adhesion molecules and extracellular matrix components in Warthin's tumor of the salivary gland with immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). Various growth factors and their receptors, such as transforming growth factor-alpha (TGF-alpha), heparin-binding epidermal growth factor-like growth factor (HB-EGF), TGF-beta2, TG-beta3, insulin-like growth factor (IGF)-I and -II, vascular endothelial growth factor (VEGF), EGF receptor (EGFR), erb-B4, TGF-betaRI and II, Flt and Flk-1 and IGF receptor Ibeta, were found in epithelial cells and/or in some lymphoid cells. Fibronectin, laminin, collagen type IV and tenascin were found in stroma of the lymphoid tissue. Integrins such as alpha3beta1 and beta3, Thy-1, CD44 and VCAM-1 were also expressed in epithelial and/or lymphoid cells. These various proteins may interact and regulate the proliferation and cell attachment of both epithelial and lymphoid components in this unique tumor.

Adenolymphoma↗
PubMed2001

Novel immunotherapy for peritoneal dissemination of murine colon cancer with macrophage inflammatory protein-1beta mediated by a tumor-specific vector, HVJ cationic liposomes.

A critical issue for cancer treatment is control of metastatic or disseminated tumors. Although immune gene therapy has been considered as a possible strategy for treatment of such tumors, successful results have not yet been obtained. To evoke antitumor immunity more efficiently, macrophage inflammatory protein-1beta (MIP-1beta) was used for gene therapy of colon cancer in mice. Injection of hemagglutinating virus of Japan (HVJ) cationic liposomes-MIP-1beta into subcutaneous tumor masses resulted in local expression of MIP-1beta and local accumulation of CD4(+) T lymphocytes. Few studies of cancer gene therapies have targeted peritoneal dissemination. In a mouse model of peritoneal dissemination of colon tumor, we used a luciferase-based assay to demonstrate that HVJ cationic liposomes had high tumor specificity and were effective vectors for transfer of genes in peritoneal dissemination. When mice were treated by intraperitoneal injection of HVJ cationic liposomes containing the MIP-1beta gene, the survival periods of the MIP-1beta-treated mice were significantly longer than those of control mice. Therefore, this HVJ cationic liposome strategy may serve as a powerful tool against peritoneal disseminated cancer.

Animals↗
PubMed2001

Chemical diversity in lipopeptide antifungal antibiotics.

In the course of screening for antifungal antibiotics, we have discovered a novel series of lipopeptide compounds structurally related to, but highly superior to, echinocandin B in terms of their water solubility due to the presence of a sulfate residue. These compounds, WF11899s, WF738s, WF14573s, WF16616 and WF22210, and their derivatives have diversity in their nuclear structures and acyl side chains. The producing strains were classified into two groups, the Coleomycetes group and the Hyphomycetes group. Compound FK463, a derivative of WF11899A, is currently in Phase 3 clinical development as a novel antifungal antibiotic.

Animals↗
PubMed2001

Application of an integrated prepstation-GC-NPD system to automated continuous measurement of formaldehyde and acetaldehyde in the atmosphere.

An integrated PrepStation-gas chromatography-nitrogen phosphorus detection (GC-NPD) system was used for the fully automated, continuous, low parts per billion analysis of lower aldehydes in the atmosphere. Analysis involved a solid phase extraction procedure based on the collection of aldehydes from air pumped through a silica gel cartridge impregnated with acidified 2,4-dinitrophenylhydrazine (DNPH). Automated continuous measurements were performed with a typical temporal resolution of 3 h, including 146 min for sampling of air at a constant air flow rate of 0.15 L min(-1) and 34 min for the preparation and extraction of several cartridges. Analysis of samples could be performed in parallel by using previously defined scheduler settings from separate, independent software to operate the PrepStation module. GC-NPD measurements were highly repeatable, and relative standard deviations were < 3.0%. Recoveries for all compounds were 88-101%. DNPH decomposition products did not adversely affect the quantitative determination of aldehyde DNPHs; therefore, it was not necessary to remove excess DNPH reagent. The limits of quantification (10sigma of the blank hydrazones) of formaldehyde and acetaldehyde were 2.2 and 1.2 ppb, respectively, for 21.9 L (0.15 L min(-1) for 146 min) of air sample volume. The integrated PrepStation GC-NPD system gave results comparable to those of the Sep-Pak DNPH silica cartridge method.

Air Pollutants↗
PubMed2001

Shifted positioning of the anticodon nucleotide residues of amber suppressor tRNA species by Escherichia coli arginyl-tRNA synthetase.

Cytidine in the anticodon second position (position 35) and G or U in position 36 of tRNAArg are required for aminoacylation by arginyl-tRNA synthetase (ArgRS) from Escherichia coli. Nevertheless, an arginine-accepting amber suppressor tRNA with a CUA anticodon (FTOR1Delta26) exhibits suppression activity in vivo [McClain, W.H. & Foss, K. (1988) Science, 241, 1804-1807]. By an in vitro kinetic study with mutagenized tRNAs, we showed that the arginylation of FTOR1Delta26 involves C34 and U35, and that U35 can be replaced by G without affecting the activity. Thus, the positioning of the essential nucleotides for the arginylation is shifted to the 5' side, by one residue, in the suppressor tRNAArg. We found that the shifted positioning does not depend on the tRNA sequence outside the anticodon. Furthermore, by a genetic method, we isolated a mutant ArgRS that aminoacylates FTOR1Delta26 more efficiently than the wild-type ArgRS. The isolated mutant has mutations at two nonsurface amino-acid residues that interact with each other near the anticodon-binding site.

Amino Acid Sequence↗
PubMed2001

Effect of bile acids on absorption of nitrendipine in healthy subjects.

AIMS: To examine whether bile acids such as ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) can influence the absorption of nitrendipine, a highly lipophilic calcium channel blocker. METHODS: Six healthy subjects received nitrendipine (10 mg) with and without UDCA (50 mg) and CDCA (200 and 600 mg) with an interval of 1 approximately 2 weeks between study phases. RESULTS: Bile acids decreased the Cmax (ng ml(-1)) [control 10.9 +/- 5.8 (mean+/- s.d.), UDCA 5.0 +/- 4.7 (95% confidence interval for difference; 3.9, 7.8, P = 0.0006), CDCA (600 mg) 5.0 +/- 3.9 (2.6, 9.2, P = 0.0059)] and AUC (ng ml(-1) h) [(control; 60 +/- 36, UDCA 15 +/- 13 (20, 73, P = 0.0064), CDCA (600 mg) 19 +/- 19 (21, 63, P = 0.0038)] of nitrendipine, while elimination half-life remained unchanged. CONCLUSIONS: These results suggest that the amount of nitrendipine absorbed was decreased when the drug was administered with UDCA and CDCA.

Adult↗
PubMed2001

Different effects of St John's wort on the pharmacokinetics of simvastatin and pravastatin.

OBJECTIVE: St John's Wort, a widely used herbal product, is an inducer of CYP3A4 and it decreases blood concentrations of CYP3A4 substrates. The effects of St John's Wort on the pharmacokinetics of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors simvastatin (an inactive lactone pro-drug) and pravastatin were determined in this study. METHODS: Sixteen healthy male subjects (n = 8 in group 1 and n = 8 in group 2) took a St John's Wort caplet (300 mg) or matching placebo three times a day for 14 days in a double-blind, crossover study. On day 14, a single oral dose of 10 mg simvastatin and 20 mg pravastatin was given to subjects in group 1 and group 2, respectively. Blood samples were obtained during a 24-hour period after the administration of each drug. RESULTS: Repeated St John's Wort treatment tended to lower plasma simvastatin concentration and significantly (P <.05) lowered concentrations of simvastatin hydroxy acid, its active metabolite. The peak concentration in plasma (ratio, 0.72 of placebo) of simvastatin hydroxy acid tended to be decreased and its area under the plasma concentration-time curve between time zero and 24 hours after administration (ratio, 0.48 of placebo) was significantly decreased (P <.05) by St John's Wort. On the other hand, St John's Wort did not influence plasma pravastatin concentration. No significant differences were observed in the elimination half-life of simvastatin or pravastatin between the placebo and St John's Wort trials. CONCLUSIONS: This study showed that St John's Wort decreases plasma concentrations of simvastatin but not of pravastatin. Because simvastatin is extensively metabolized by CYP3A4 in the intestinal wall and liver, which are induced by St John's Wort, it is likely that this interaction is partly caused by the enhancement of the CYP3A4-mediated first-pass metabolism of simvastatin in the small intestine and liver.

Adult↗
PubMed2001

Effects of fibrin glue on injured rabbit ureter.

BACKGROUND AND OBJECTIVE: Fibrin glue is used as a hemostatic agent, has potential as a tissue adhesive, and may promote tissue healing. The histologic effects of fibrin glue on the ureter have not yet been fully investigated. We studied the effect of fibrin glue on the thickness of various layers of injured and uninjured ureters and its effect on vessel density in the rabbit model. MATERIALS AND METHODS: Rabbits were divided into two groups. The ureters were exposed using a midline abdominal incision. In the study group, one of the ureters was crushed, and fibrin glue was instilled around both ureters. In the control group, one of the ureters was crushed, but no fibrin glue was instilled. The animals were sacrificed at 6 weeks and the ureters examined histologically. Using NIH Image Analysis solftware, the thickness of the urothelium, muscular, and adventitial layers and the cross-sectional area of the ureters were measured. The vessel density of the ureters was also assessed. RESULTS: Whereas the thickness of the epithelium was increased in the crushed ureters treated with fibrin glue (20.7 microm v 15.3 microm), the thickness was reduced in the uncrushed ureters treated with fibrin glue compared with controls (16.3 microm v 19.8 microm). There was no statistically significant difference in the thickness of the muscular or adventitial layers in the study and control groups. There was a reduction in the cross-sectional area of the uncrushed ureters treated with fibrin glue compared with controls (7,095 microm2 v 9,409 microm2). In addition, the vessel density in the crushed ureters was reduced in ureters treated with fibrin glue compared with controls (0.00067/microm2 v 0.00108/micro2). In the uncrushed ureters, the difference was not statistically significant. CONCLUSIONS: Fibrin glue has potential as an adhesive agent in the ureter and may promote healing. It may affect epithelial layer thickness and vessel density of the ureter, but these effects were variable. Fibrin glue does not appear to have significant effects on the ureteral muscular and adventitial layers or on the overall cross-sectional area of all three layers. These results indicate that fibrin glue does not appear to have a detrimental effect on the ureter.

Animals↗
PubMed2001

The down-regulation of glutathione peroxidase causes bovine luteal cell apoptosis during structural luteolysis.

Prostaglandin (PG) F(2)a is known to initiate luteal cell apoptosis in the bovine corpus luteum (CL) via its specific receptor (FP) on the luteal membrane by inducing intracellular Ca(2+) mobilization and the activation of PKC. In order to identify the signaling components involved in cell apoptosis, mRNA levels and activities of antioxidative enzymes were analyzed using bovine CL at different stages of the estrous cycle. Northern blot analysis revealed that the levels of two isozymes of superoxide dismutase (SOD), the Mn and Cu/Zn types, and catalase are highly enriched in the middle estrous phase, whereas glutathione peroxidase (GPx) levels gradually decrease as the estrous cycle progresses. The incubation of bovine luteal cells with H(2)O(2) and mercaptosuccinate (MS), a specific inhibitor of GPx, resulted in an increase in chromatin DNA condensation and apoptotic DNA fragmentation. Analyses of the enzymatic activities of GPx and catalase support the RNA data, indicating that H(2)O(2) produced due to the lack of GPx is a potent inducer of luteal cell apoptosis.

Animals↗
PubMed2001

Recent advances in the pathology of alcoholic myopathy.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Victor R. Preedy and Junko Adachi. The presentations were (1) Alcoholic myopathy: Past, present and future, by Timothy J. Peters and Victor R. Preedy; (2) Protein adducts in the type I and II fiber-predominant muscles of the ethanol-fed rat, by Simon Worrall, Seppo Parkkila, and Onni Niemela; (3) Hydroperoxides and changes in alcoholic myopathy, by Junko Adachi, Migiwa Asamo, and Yasuhino Ueno; and (4) A close association between testicular atrophy, muscle atrophy, and the increase in protein catabolism after chronic ethanol administration, by Kunihiko Takeda, Masayoshi Yamauchi, Kazuhiko Sakamoto, Masaru Takagi, Hisato Nakajima, and Gotaro Toda.

Alcoholism↗
PubMed2001

Association of polymorphism in the alcohol dehydrogenase 2 gene with alcohol-induced testicular atrophy.

BACKGROUND: Alcohol abuse can induce testicular atrophy, but it only occurs in some alcoholics. Alcohol dehydrogenase (ADH) is located principally on the Leydig cells. METHODS: To investigate whether genetic polymorphism of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 was related to alcoholic testicular atrophy, we determined restriction fragment-length polymorphisms of the ADH2 and ALDH2 genes in 43 Japanese male alcoholics and 50 healthy subjects. An orchidometer was used to determine the testicular size. RESULTS: Less than 16 ml in testicular size was defined as testicular atrophy. Testicular atrophy was found in 24 (55.8%) cases out of 43 alcoholics. Digestion with MaeIII and MboII after polymerase chain reaction amplification showed that the ADH21 allele frequency was significantly higher in patients with testicular atrophy than in those without testicular atrophy (chi2 = 4.665, p = 0.031), whereas no significant association was observed between testicular atrophy and the ALDH2 gene. CONCLUSIONS: The ADH21 allele may be associated with alcoholic testicular atrophy.

Adult↗