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Biomedical subjects

S Maeda

Publications and source records attributed to S Maeda.

At least 127 records · Page 7Linked to original sources
PubMed2001

A comparison of vibration magnitudes on the tool with different subject according to the ISO 8662-7 standard.

Recently, ISO has defined the guidelines for the evaluation of the measurement and exposure limits of hand-transmitted vibrations at the handle of hand-held portable power tools. In a measurement of vibrations at pneumatic impact wrenches that tighten and remove screws. ISO 8862-7 standard: 1997 and ISO 5349 standard: 1986 are set as international standards. In order to make an exact measurement of the quantities of vibrations exposed to the hand-arm system of a human body, ISO 8662-7 gives specifications to a measurement device and a loading device. As to a measurement device, for instance, the mass, installation method etc. of transducers and mechanical filters are defined. In addition, it specifies with each tolerance the working conditions of a pneumatic tool, the number of revolutions of socket in a loading device, the feed force, the number of subjects, and such an evaluation method as how to decide a declaration value of vibrations. These specifications give toolmakers a comparative measurement of vibration values of their tools before shipment. Meanwhile, although the measurement condition described in ISO8662-7: 1997 is that skilled operators conduct vibration measurement, no provisions as to operators are made in detail. Hence, this study focuses its concern on ambiguous work experience years in measuring vibrations of the tools in conformity with ISO 8662-7, and hereby the effect of years of work experience upon measurement values is considered and at the same time a knowledge of how to select operators is made clear.

Adult↗
PubMed2001

Homozygous serum amyloid P component-deficiency does not enhance regression of AA amyloid deposits.

Serum amyloid P component (SAP) is a common protein constituent of all types of amyloid deposits. Using SAP-deficient mice generated through gene targeting, we and others have shown that SAP significantly promotes amyloid deposition. It has been speculated that SAP protects amyloid fibrils from degradation by coating their exterior surface. To assess potential ways of treating individuals with amyloidosis, we examined the persistence of splenic AA amyloid fibrils in SAP-deficient and wild-type mice. No enhancement in the rate of regression of splenic AA amyloid was observed in the SAP-deficient mice relative to wild-type mice. These results present, for the first time, evidence that lack of SAP in AA amyloid deposits does not enhance regression of the deposits in vivo and suggest that dissociation of bound SAP from AA amyloid deposits would not significantly accelerate regression of the deposits in vivo.

Amyloidosis↗
PubMed2001

Methylation of CpG loci in 5'-flanking region alters steady-state expression of adenomatous polyposis coli gene in colon cancer cell lines.

The APC genetic locus has been linked to the tumorigenesis and progression of colorectal cancer, although the precise mechanism of its involvement in this disease remains unknown. We used high sensitivity mapping of the methylated cytosine, Northern blot analysis and immunocytochemical staining in six colorectal cancer cell lines (DLD-1, SW480, Colo320, HT29, WiDr, and Colo201) to examine the relationship between the methylation status of the CpG loci in the 5'-flanking region of the APC gene and its expression. APC mRNA expression levels determined by Northern blot analysis correlated well with APC protein levels visualized by immunocytochemistry. In these colorectal cancer cell lines, no major genetic alterations of the APC gene, such as amplification or deletion, were detected. Analysis of the epigenetic control of APC gene expression in these lines revealed that methylation of the CpG loci in the 5'-untranslated region of APC mRNA repressed steady-state expression of the gene. Furthermore, epigenetic alteration of the APC gene was independent of the APC protein truncation and CpG methylation of the hMLH1 promoter. Although less eminent than protein truncation by point mutation within the coding region of the APC gene, epigenetic alteration suppressing APC gene expression may significantly contribute to oncogenesis and the progression of colorectal cancer.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[Mechanism of drug resistance in Helicobacter pylori].

Clarithromycin is one of the most important antibiotics for H. pylori eradication. However, 5-10% was reported to be resistant. It has been shown that one point mutation in the 23S rRNA gene is associated with resistance to clarithromycin. To detect H. pylori infection and the mutation simultaneously, we have designed PCR primers specific for H. pylori, and established assays of PCR-RFLP and PCR-preferential homo-duplex formation (PHFA). Using this assay, we can detect mixed infections with wild and mutant-strains. The prevalence of mutant infection increased through clarithromycin-based eradication. However, the existence of mutant strains had been confirmed before therapy in most cases who 'converted' to mutant after therapy. Metronidazole is also one of the most important antibiotics for eradication. However, 5-50% was reported to be resistant. It has been shown that rdx gene mutation is associated with resistance. It is reported that inactivation of the rdx gene is frequently, but not always, associated with resistance to metronidazole. Amoxicillin resistant strains were rare (1.2% in Japanese strains). It is reported that penicillin-binding protein might play a role in the resistance. By detecting of the resistance based on the molecular mechanism, patients can be treated with adequate antibiotics with information about resistance.

Clarithromycin↗
PubMed2001

[Articulatory compensation after supracricoid partial laryngectomy with cricohyoidoepiglottopexy].

OBJECTIVES: The consequences of the modification of the glottis and the shortening of the vocal tract after supracricoid partial laryngectomy (SCPL) with cricohyoidoepiglottopexy (CHEP) were investigated prospectively on ten patients. An acoustic analysis of the transfer function of the vocal tract was performed by measuring the formant frequencies of the [a] and [i] vowels. The articulation compensatory mechanisms of the vocal tract were observed with cinefluoroscopy in order to evaluate the phonation and articulation constraints. PATIENTS AND METHODS: Ten male patients were recorded before surgery and at six, 12 and 18 months after surgery. The results were compared with those of 10 male normal speakers having the same range of age. For the acoustic measures, we tracked the three first formant frequencies of the cardinal vowels [a] and [i], before and after surgery. Articulation investigation was performed with cinefluoroscopy for the vowels [a] and [i] uttered by two of the 10 patients. RESULTS: For the [a] vowel, the acoustic analysis showed higher values for all three formants, related to the shortening of the vocal tract after surgery. For the [i] vowel, the lowering of the second formant frequencies after surgery was related to an articulatory compensation. Cinefluoroscopy confirmed the shortening of the vocal tract, the tongue-root retraction for voicing and the anterior position of the tip of the tongue for the [i] vowel. CONCLUSIONS: The consequences of the shortening of the vocal tract after SCPL with CHEP can be evaluated, non invasively, by means of acoustic analysis. The understanding of the articulation compensatory mechanisms resulting from voicing constraints should help voice rehabilitation and improve oral communication in such patients.

Adult↗
PubMed2001

[Tumor markers for hepatocellular carcinoma].

The diagnosis of hepatocellular carcinoma (HCC) is based mainly on serological tumor markers, such as alpha-fetoprotein, L3% fraction thereof and PIVKA-II, and imaging modalities. These are not correlated but are complementary. Hence, a combination designed to take advantage of the characteristics of each needs to be worked out. First, it is necessary to identify the patients at high risk for developing HCC, such as those with chronic hepatitis or liver cirrhosis, and in the follow-up conduct regular check-ups for serological tumor markers. Those testing positive for any marker are at the highest risk for developing HCC, even when imaging fails to disclose any space-occupying lesions. Following these high-risk patients, in concert with imaging, enables accurate evaluation of the efficacy of therapies for HCC. Since serological tumor markers can signal the development of HCC earlier than any other laboratory test, they offer an excellent means of identifying relapsing HCC. Equally important in the management of patients with HCC are biological indicators for malignancy, selection of therapeutic interventions and prediction of the outcome.

Biomarkers↗
PubMed2001

[A case of advanced gastric cancer with multiple liver metastases in an elderly patient that responded dramatically to UFT therapy].

An 88-year-old female patient suffering from Borrmann type 3 advanced gastric cancer complicated by multiple hepatic metastases underwent a total gastrectomy. A small dose of 200 mg/day of UFT was administered orally every day postoperatively. At postoperative month 6, a marked diminishment of the hepatic metastatic lesions was noted. Resection of the primary lesion with a regimen of a small oral dose of UFT was remarkably effective in this elderly gastric cancer patient with complications from multiple hepatic metastases.

Adenocarcinoma↗
PubMed2001

[Inflammatory cytokines (IL-4, IL-5 and IL-13)].

The polarized Th2 cells play an important role in the pathogenesis of atopic asthma as well as in the induction of airway inflammation. Th2 cytokines, such as IL-4, IL-5 and IL-13, are pivotal in regulating the allergic phenotype, the IgE response or the inflammatory cell-mediated function. Selective inhibition of Th2 cytokines by pharmacologic agents, including anti-cytokine blocking antibody, cytokine mutant and soluble cytokine receptor, will contribute to asthma therapy. Strategies based on blocking key signaling cytokines are also discussed.

Anti-Asthmatic Agents↗
PubMed2001

[Reference values of serum lipid].

The guideline for the reference value of serum lipid(total cholesterol, LDL-cholesterol, HDL-cholesterol and triglyceride) was proposed by the Japan Atherosclerosis Society in 1997. These values are utilized for the diagnosis and treatment of hyperlipidemia to protect patients from ischemic heart disease. The upper limit of reference value was not determined by the 95 percentile range from healthy subjects, but on the basis of clinical data on serum lipid in the Japanese. This way to determine the reference value will be suitable in case of lipid, because there is a tendency to increase cholesterol level in the Japanese for these thirty years. The standardization for each lipid assay is crucial. The CDC-established Reference Methods for measuring total cholesterol(TC), HDL-C. LDL-C, and triglyceride(TG) are used to set reference values for the serum pools used for LSP(Lipid Standardization Panel) standardization. In Japan, the routine methods for cholesterol and triglyceride have been proposed by the special committee in the Japan Society of Clinical Chemistry. In contrast, homogeneous assay for HDL- and LDL-C, which are used routinely at present, have still some problems in the point of accuracy. A new ELISA for Lp(a) has been developed using antibody not reacting to kringle IV type 2. Its standardized assay, thus, will be available sooner or later. With respect to other lipid-related test such as RLP(remnant-like particles) and oxidized LDL, it is necessary to accumulate more clinical data for the determination of reference value.

Apoproteins↗
PubMed2000

Virulence factors of Helicobacter pylori responsible for gastric diseases in Mongolian gerbil.

Helicobacter pylori infection induces various gastroduodenal diseases. We examined the role of two genes, vacA and cagE, in the gastric pathogenesis induced by H. pylori using a long-term (62 wk) animal model. Reportedly, both genes are associated with the virulence of H. pylori: vacA encodes vacuolating cytotoxin, and cagE, with other genes in the cag pathogenicity islands, encodes a type IV secretion system. Mongolian gerbils were challenged in this study by a wild-type TN2 strain and its isogenic mutants of cagE or vacA. The wild-type and vacA mutants induced severe gastritis, whereas cagE mutants induced far milder changes. Gastric ulcer was induced at the highest rate (22/23) by the wild-type TN2, followed by the vacA mutant (19/28). No ulcer was found in the gerbils infected with the cagE mutant (0/27) or in controls (0/27). Intestinal metaplasia was also found in the gerbils infected with the wild-type (14/23) or vacA mutant (15/28). Gastric cancer developed in one gerbil with wild-type infection and in one with vacA mutant infection. In conclusion, the knocking out of the cagE gene deprived wild-type H. pylori of the pathogenicity for gastritis and gastric ulcer, suggesting that the secretion system encoded by cag pathogenicity island genes plays an essential role.

Adenocarcinoma↗
PubMed2000

Co-expression of p53 and bcl-2 may correlate to the presence of epstein-barr virus genome and the expression of proliferating cell nuclear antigen in nasopharyngeal carcinoma.

Epstein-Barr virus (EBV) has been well documented in the aetiology of nasopharyngeal carcinoma (NPC), although its role as well as the genetic basis in the genesis of NPC have not been elucidated. The p53 gene mutations are infrequently found in NPC, but the expression of p53 protein, as well as bcl-2 oncoprotein, has been reported in a high percentage of cases, and also in association with EBV. Proliferating cell nuclear antigen (PCNA) has also been shown to be increased in NPC, suggesting its association among the overexpression of p53 and bcl-2 oncoprotein. We undertook this study to evaluate the correlation among these abnormalities in the development of NPC. The expression of p53 protein, bcl-2 oncoprotein, and the level of PCNA were investigated by immunohistochemistry in 53 patients with NPC. Twenty tissue samples from these patients were studied for p53 gene mutations by single strand conformation polymorphism (SSCP) and DNA sequencing as well as EBV genomes by polymerase chain reaction. Among the 53 specimens, 42 (79%) showed expression of p53 protein and 40 (75%) gave positive result for bcl-2 oncoprotein. A significant association was found between p53 expression and bcl-2 oncoprotein (P=0.002; Fisher's exact test) with 68% of the patients showing coexpression of both markers. The PCNA labelling index in the 53 patients varied from 5% to 80%. High PCNA labelling index was frequently found in the patients with overexpression of p53 protein and bcl-2 oncoprotein. The PCNA index in patients with p53 expression was significant higher than in those without p53 expression (P=0.002). Of the 20 patients, p53 mutations were found in four cases. EBV genomes were detected in 14 cases of which 12 cases showed overexpression of both p53 and bcl-2 and one case with only p53 expression and one case with bcl-2 expression. EBV genomes were detected in two cases with p53 mutations. We conclude that EBV is the important etiologic factor in NPC which may be involved in p53 and bcl-2 overexpression. The mutant p53 protein is correlated to deregulation of PCNA. p53 mutations participate in a small proportion of the tumorigenesis.

Carcinoma↗
PubMed2000

Disruption of aldose reductase gene (Akr1b1) causes defect in urinary concentrating ability and divalent cation homeostasis.

Aldose reductase (AKR1B1) is the first enzyme in the polyol pathway through which glucose is converted to sorbitol, and has been implicated in the etiology of diabetic complications. However, its physiological role is still not well understood. In the kidney, AKR1B1 is quite abundant in the collecting tubule cells and thought to provide protection against hypertonic environment. We report here that the mice lacking AKR1B1 showed hypercalciuria, hypercalcemia, hypermagnesemia, and reduced ability to concentrate urine, suggesting a new physiological role of AKR1B1 in divalent cation homeostasis.

Aldehyde Reductase↗
PubMed2000

Bicarbonate binding activity of the CmpA protein of the cyanobacterium Synechococcus sp. strain PCC 7942 involved in active transport of bicarbonate.

The cmpABCD operon of the cyanobacterium Synechococcus sp. strain PCC 7942 encodes an ATP-binding cassette transporter involved in HCO(3)(-) uptake. The three genes, cmpBCD, encode membrane components of an ATP-binding cassette transporter, whereas cmpA encodes a 42-kDa cytoplasmic membrane protein, which is 46.5% identical to the membrane-anchored substrate-binding protein of the nitrate/nitrite transporter. Equilibrium dialysis analysis using H(14)CO(3)(-) showed that a truncated CmpA protein lacking the N-terminal 31 amino acids, expressed in Escherichia coli cells as a histidine-tagged soluble protein, specifically binds inorganic carbon (CO(2) or HCO(3)(-)). The addition of the recombinant CmpA protein to a buffer caused a decrease in the concentration of dissolved CO(2) because of the binding of inorganic carbon to the protein. The decrease in CO(2) concentration was accelerated by the addition of carbonic anhydrase, indicating that HCO(3)(-), but not CO(2), binds to the protein. Mass spectrometric measurements of the amounts of unbound and bound HCO(3)(-) in CmpA solutions containing low concentrations of inorganic carbon revealed that CmpA binds HCO(3)(-) with high affinity (K(d) = 5 microm). A similar dissociation constant was obtained by analysis of the competitive inhibition of the CmpA protein on the carboxylation of phosphoenolpyruvate by phosphoenolpyruvate carboxylase at limiting concentrations of HCO(3)(-). These findings showed that the cmpA gene encodes the substrate-binding protein of the HCO(3)(-) transporter.

ATP-Binding Cassette Transporters↗
PubMed2000

Pheromone-producing cells in the silkmoth, Bombyx mori: identification and their morphological changes in response to pheromonotropic stimuli.

A method to isolate functional clusters of viable pheromone gland cells of Bombyx mori was developed. The 8th-9th intersegmental invaginated membrane corresponding to the pheromone gland was dissected, trimmed and separated into two distinct layers, the outer and inner layers, by enzymatic digestion with papain. The outer layer mainly consists of cuticle, while the inner layer consists of homogeneous cells with many refractile granules. The solubilized microsome fraction prepared from the inner layer retained the ability to produce bombykol in vitro, whereas the outer layer fraction did not produce bombykol. Moreover, in tissue incubations, the inner layer - but not the outer layer - produced bombykol in response to the pheromonotropic peptide TKYFSPRLamide, ionomycin and calcium ionophore A23187. These results indicate that the inner-layer cells are indeed the pheromone-producing cells, which retain their functional integrity after separation with papain. These cells could be cultured successfully in Grace's medium for at least 5days.The presence or absence of pheromonotropic stimuli prior to dissection greatly influenced the size, number and distribution of refractile granules in the cytoplasm of the pheromone-producing cells. Staining with Nile Red proved that these refractile granules were lipid droplets. When pheromone production was studied under normal conditions or stimulated in decapitated females with pheromone-biosynthesis-activating neuorpeptide (PBAN) charge, the size of lipid droplets observed in the pheromone-producing cells reduced prominently and their number increased dramatically with time. By contrast, when pheromone production was suppressed by decapitation, the size and number of the lipid droplets remained constant. Lipid droplets observed in the pheromone-producing cells could be carriers of pheromone precursors and/or the pheromone bombykol. The present results suggest that the isolated cell preparation can be used for quantitative visualization of the cellular dynamics during pheromone production in B. mori.

Journal Article↗
PubMed2000

Assessment of gastric carcinoma risk associated with Helicobacter pylori may vary depending on the antigen used: CagA specific enzyme-linked immunoadsorbent assay (ELISA) versus commercially available H. pylori ELISAs.

BACKGROUND: Previous epidemiologic studies produced inconsistent results when examining the relation between Helicobacter pylori infection and the risk of gastric carcinoma by measuring various anti-H. pylori antibodies. This study investigated the increased risk of cancer by examining different antibodies, including the specific anti-CagA antibody and antibodies from two commercially available kits. METHODS: An ELISA for the detection of serum anti-CagA was established using a recombinant CagA protein that the authors previously reported. Serum anti-CagA titer was determined for 80 patients with gastric carcinoma and 80 gender- and age-matched controls. Two anti-H. pylori antibodies from the commercially available kits HEL-p (Amrad, Kew Vic, Australia) and HM-CAP (Enteric Product Inc., Westbury, NY) were also evaluated. RESULTS: Anti-CagA seropositivity differed significantly between gastric carcinoma patients and controls (92.5% vs. 55.0%; P = 0. 0001), showing an odds ratio of 10.4 (95% confidence interval [CI]: 4.23-29.74). The difference was less prominent for the seropositivity of HEL-p (77.5% vs. 58.8%; P = 0.0139; odds ratio: 2. 38; 95% CI: 1.20-4.82) and insignificant for that of HM-CAP (65.0% vs. 57.5%; P = 0.4325; odds ratio: 1.30; 95% CI: 0.68-2.49). CONCLUSIONS: The current study revealed that the antibody assay system used could be one important factor in the assessment of gastric carcinoma risk for patients with H. pylori.

Adult↗
PubMed2000

Development of infantile rat ovaries autotransplanted after cryopreservation by vitrification.

We cryopreserved infantile rat ovaries by vitrification and assessed their viability by autotransplantation. Hemilateral ovarian transplantation was performed on rats on postnatal Days 10 to 12. The left ovary of each rat was dissected out, cryopreserved by vitrification using a modified vitrification solution (VS1), and then autotransplanted under the capsule of the right kidney. The right ovary of each rat was removed. For the control, the left ovary was dissected out from each rat and was immediately transplanted by the same procedure, without cryopreservation. Rats were nursed until weaning, and then the day of vaginal opening, estrous cyclicity from the day of vaginal opening until postnatal Day 84, and histology of ovarian grafts at postnatal Day 84 were examined. The time course of development of endocrine function of cryopreserved grafts was similar to that of fresh grafts. In ovarian transplants recovered on postnatal Day 84, antral follicles and corpora lutea (CL) were observed in addition to small follicles, although the number of antral follicles in cryopreserved grafts was smaller than in the fresh grafts. These results indicate that cryopreservation of ovarian tissue by vitrification can be used for the preservation of fertility and endocrine function of ovaries.

Animals↗
PubMed2000

Induction of S100A4 gene expression inhibits in vitro invasiveness of human squamous cell carcinoma, KOSC-3 cells.

S100A4 is considered functionally involved in metastasis and invasiveness of rodent and human mammary tumors. We screened the expression of S100A4 in human squamous cell carcinoma cell lines, and found 2 cell lines which were highly invasive, but did not express any noticeable extent of S100A4. To examine whether the expression of S100A4 regulated invasiveness of squamous cell carcinoma, we transfected S100A4 cDNA into KOCS-3 and HSC-4 squamous cell carcinoma cells. The transfectants from KOSC-3 cells expressing sense S100A4 decreased invasiveness by 80% compared with cells of the wild type or those with the vector only.

Animals↗