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Biomedical subjects

S Kasai

Publications and source records attributed to S Kasai.

At least 19 recordsLinked to original sources
PubMed2003

Development of a new membrane-type heated humidifier for laparoscopic surgery.

BACKGROUND: Recently, several animal studies showed that the core body temperature falls during pneumoperitoneum, and this hypothermia could be prevented by using heated and humidified gas insufflation. However, there are no satisfactory heated humidifiers to meet this purpose. Therefore, we developed a new membrane-type heated humidifier. MATERIALS AND METHODS: The newly developed heated humidifier employs an ion-exchange membrane (Nafion: Du Pont Co. Ltd) tube that passes water selectively in molecular form and a gas compartment is completely separated from distilled water to prevent infection. This humidifier consists of a Nafion tube assembly and a case that includes the heater. A perforated protecting tube is located outside the Nafion tube to prevent direct contact with the Nafion tube when it is assembled. The Nafion tube assembly is inserted in the case, and dry gas flows inside of the Nafion tube. The space between the case and the Nafion tube assembly is filled with distilled water. A heater raises the temperature of the distilled water, and heat and water vapor are transferred to cold and dry gas through the Nafion membrane. Four different types of insufflators were involved in this performance comparison study: a Nafion-based heated and humidified insufflator, a conventional heated insufflator, a conventional heated and humidified insufflator, and a conventional cold and dry insufflator. Temperature and relative humidity were measured once each minute for 15 min, which was repeated four times. Each insufflator was operated at two rates of flow: 5 L/min and 10 L/min. RESULTS: Temperature and humidity of the conventional cold and dry insufflator, the Nafion membrane-type heated and humidified insufflator, the conventional heated insufflator, and the conventional heated and humidified insufflator measured at the distal end of circuit reached 22.0 +/- 0.2 degrees C and 0%, 36.7 +/- 1.1 degrees C and 100%, 29.0 +/- 0.4 degrees C and 0%, and 31.3 +/- 0.4 degrees C and 70.5 +/- 5.3% in 15 min at 5 L/min flow rates. At 10 L/min flow rates, temperature and humidity were almost the same as those at 5 L/min. The membrane-type heated humidifier demonstrated statistically significant improvement in both the temperature ( p < 0.0001) and relative humidity ( p < 0.0001) parameters in comparison to the conventional normal, heated, or heated and humidified insufflators at 5 L/min and 10 L/min continuous flow rate in statistics using repeated-measure ANOVA. CONCLUSION: This newly developed heated humidifier offers the great advantages of maintaining intraabdominal temperature and humidity in comparison to conventional insufflators for laparoscopic surgery.

Equipment Design↗
PubMed2002

How laminin-1 can be recognized by the protozoan parasite Tritrichomonas foetus: possible role played by the extracellular matrix glycoprotein in both cytoadhesion and cytotoxicity exerted by the parasite.

The isoform 1 of the extracellular matrix glycoprotein Laminin is known to be an important ligand for some parasitic protozoa including Trichomonas vaginalis. The bovine parasite Tritrichomonas foetus seems to display a similar recognition process to laminin-1, as some amino acid sequences found in the LNS module of laminin-1 can also be recognized by this parasite. Which of the laminin-1 residing adhesion sequences are recognized by T. foetus, and the role played by such a protein-cell recognition process in both cytoadhesion and cytotoxicity exerted by the parasite are the subjects briefly reviewed and discussed here.

Animals↗
PubMed2002

Relation between colour vision loss and occupational styrene exposure level.

AIMS: To investigate the relation between colour vision loss and the exposure level of styrene. Exposure level included the current exposure concentration, past cumulative exposure, and the maximum exposure level in the past. METHODS: Colour vision was examined by the Lanthony desaturated panel D-15 test for 76 subjects exposed to styrene in a fibreglass reinforced plastics boat plant (as an exposed group) and 102 non-exposed subjects (as a control group). The current exposure level was expressed by the concentration of atmospheric styrene and end shift urinary mandelic acid (MA) and phenylglyoxylic acid (PGA) levels. The individual cumulative exposure index (CEI) was calculated, based on the exposure frequency and urinary MA concentrations measured for the past eight years. RESULTS: The Colour Confusion Index (CCI) of the exposed group showed a significant difference from the age matched controls. However, only a slight significant relation was found between CCI and the concentration of urinary MA plus PGA. In this study, the exposed group was further divided into two subgroups (as sub-MA+PGA groups) by the median of urinary MA plus PGA of each subject. The dividing line between the subgroups was 0.24 g/g creatinine, which was equivalent to an atmospheric concentration of styrene of about 10 ppm. The CCI values of both the sub-MA+PGA groups were significantly higher than that of the control group. The relation between CCI value and the maximum exposure concentration in the past eight years was examined. It was found that the CCI values of the group with the maximum exposure concentration of styrene over 50 ppm were significantly higher than that of the other groups. CONCLUSIONS: Exposure to styrene would impair colour vision even if the exposure concentration was lower than 10 ppm. Furthermore, if the maximum concentration of styrene exposure transiently exceeded 50 ppm in the past, the styrene related damage might remain. Thus, the safe limit of exposure to styrene and the relation between exposure to styrene and the degree of damage to ocular structure, retina, optic nerve, and brain need to be re-examined.

Adult↗
PubMed2001

A house fly gene homologous to the zinc finger proto-oncogene Gfi-1.

Gfi-1 was first cloned from rats (and subsequently from mice, chickens, and humans) and was found to be a 55-kDa protein that bound to DNA in a sequence-specific manner to act as a transcriptional repressor and proto-oncogene. Using PCR, a Gfi-1 homologous cDNA (mdGfi-1) was cloned from the house fly, Musca domestica. Comparison of the mdGfi-1-deduced amino acid sequence with those of vertebrates indicates only moderate overall homology (40.9-43.0% identity). However, these proteins are highly conserved when the zinc finger domains are compared, with mdGfi-1 having 81.0-82.2% identity to the vertebrate homologues. Within each of the six zinc finger domains there are three amino acids that are predicted to contact the DNA and these amino acids are 100% identical for all six domains for all species. Given that Gfi-1 is highly conserved from insects to vertebrates suggests this may be an important transcription factor in many taxa.

Amino Acid Sequence↗
PubMed2001

Imaging localized horseradish peroxidase on a glass surface with scanning electrochemical/ chemiluminescence microscopy.

Scanning electrochemical/chemiluminescence microscopy (SECM/SCLM) was developed for simultaneous imaging of chemiluminescence and topography of immobilized horseradish peroxidase (HRP) on a glass substrate. When the SECM tip for electrochemical generation of H2O2 scanned over the immobilized spot in an aqueous luminol solution, the immobilized enzymes catalyzed the oxidation of luminol to emit chemiluminescence, which was detected by a photon counter. The photon-counting intensity was plotted against the position of the tip to give a two-dimensional image, indicating the activity of immobilized enzymes. Since the current was sensitive to the topography of substrate, the topography image was also obtained by mapping the oxygen reduction current.

Electrochemistry↗
PubMed2001

Identification of the cobalamin-dependent methionine synthase gene, metH, in Vibrio fischeri ATCC 7744 by sequencing using genomic DNA as a template.

To confirm the presence of cobalamin-dependent methionine synthase (CDMS) in luminous bacteria, which is a prerequisite for the substantiation of our proposals on the physiological function of the lux operon, we identified the CDMS gene (metH) in Vibrio fischeri ATCC 7744. Two partial metH sequences, one located near the 5'-terminus of the gene and the other near the 3'-terminus, were sequenced by a PCR based method. To design a new set of PCR primers located on the two flanking regions of the gene, the genomic DNA was sequenced by SUGDAT method (sequencing using genomic DNA as a template) upstream or downstream from the respective partial gene sequences. Subsequently a 4.2 kb DNA fragment containing the whole metH was amplified by PCR and sequenced. The number of amino acid residues comprising the protein (1226 amino acids) was comparable to those of known CDMSs. The deduced amino acid sequence showed 85, 74, 55, 31, 30, 52, or 52% identity with that of Vibrio cholerae, Escherichia coli, Deinococcus radiodurans, Synechocystis PCC6803, Mycobacterium tuberculosis, Caenorhabditis elegans or Homo sapiens, respectively. All the predicted amino acid residues for the binding of cobalamin and S-adenosylmethionine were conserved. In the regulatory region of the V. fischeri metH, the binding site of the met repressor, MetJ, was present, although the site is atypically not present in E. coli metH or Salmonella typhimurium metH. It was shown that nucleotide sequences, even long ones, can be determined without a cloning step, if only parts of the DNA fragment to be sequenced are amplified by PCR.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed2001

Adaptive cytoprotection against acetic acid induced colonic injury in rats.

BACKGROUND AND AIMS: The phenomenon of prostaglandin dependent adaptive cytoprotection has been well established in the stomach and duodenum but not in the colon. This study investigated whether it also occurs in the colon. METHODS: Fisher rats received intracolonic administration (0.5 ml) of saline or acetic acid at low concentrations (0.01-5%) followed by high concentration (25%) at various intervals (10-720 min). The distal colon was removed 2 h after acetic acid (25%), and colonic injury was assessed macroscopically and histologically and scored. Indomethacin (5 mg/kg) or N(G)-nitro-L-arginine methyl ester (10 mg/kg) was injected intraperitoneally 1 h or 30 min before pretreatment with 1% acetic acid. RESULTS: Acetic acid (25%) administered into the colon induced 11.6+/-0.2 macroscopic scores and 10.0+/-0.4 histological scores in saline-pretreated rats, which were reduced to 0.3+/-0.2 and 1.8+/-0.5 by acetic acid (1%) pretreatment, respectively. The protective effect assessed macroscopically and histologically was dose related (0.01-1% acetic acid) and long lasting (maximal at 30 min and lasting up to 6 h). Indomethacin abolished the colonic adaptive cytoprotection while nitric oxide synthase inhibitor had no effect. CONCLUSIONS: These data show that prostaglandin dependent adaptive protection is induced by exposure of the colon to low concentrations of acetic acid, suggesting that endogenous defense mechanisms are increased in the colon by mild irritants.

Acetic Acid↗
PubMed2001

Expression and regulation of CYP6D3 in the house fly, Musca domestica (L.).

Recently, a new cytochrome P450 gene, CYP6D3, was identified from house fly. CYP6D3 was found upstream of a related gene (CYP6D1) on autosome 1. CYP6D3 cDNA sequences were obtained and compared from insecticide resistant (LPR) and susceptible (CS and Edinburgh) strains. Although each strain had a different CYP6D3 allele, the deduced amino acid sequences revealed no consistent differences between the susceptible and resistant strains. There was approximately 12-fold more CYP6D3 mRNA detected in adult LPR flies compared to CS, and the elevated level of expression in LPR was not due to gene amplification. Northern blots indicate expression of CYP6D3 mRNA is developmentally regulated with no expression in eggs, yet it is readily detectable in larvae as well as male and female adults. Phenobarbital is a well studied inducer of P450s in insects and it induced expression of CYP6D3 mRNA in both the CS (16-fold) and LPR (1.6 fold) strains. The CYP6D3 5' flanking regions were sequenced from the resistant and susceptible strains. Possible regulatory sequences within this region are discussed.

5' Flanking Region↗
PubMed2001

New antimetastatic hypoxic cell radiosensitizers: design, synthesis, and biological activities of 2-nitroimidazole-acetamide, TX-1877, and its analogues.

We designed, based on the molecular orbital (MO) calculation, synthesized, and evaluated the biological activities of the new antimetastatic hypoxic cell radiosensitizer, 2-nitroimidazole-acetamide, TX-1877, and its analogues. Each analogue has an electron-affinic imidazole group, an acetamide group and a certain hydrophilic group to control its biological effect, toxicity, and pharmacokinetics. In in vitro radiosensitization assay, most TX-1877 analogues, which have an electron affinity (EA) of more than 0.9 eV and partition coefficient (P) of more than 0.021, showed satisfactory enhancement ratios (ER > 1.60) at doses of I mM. On the other hand, imidazole analogues, such as TX-1908 (EA = 0.67 eV), TX-1910 (EA = -0.34 eV) and TX-1931 (EA = -0.37 eV), which have low electron affinities, had an ER of 1.31 or less. TX-1877 and KIN-806 effectively inhibited tumor regrowth when administered with irradiation in vivo at a dose of 0.4 mg/g. Tumor lung metastasis was inhibited by treatment with either TX-1877 or KIN-806 without irradiation at a dose of 0.4 mg/g. TX-1877 reduced markedly the mean number of metastatic lung nodules in comparison with KIN-806. Moreover, TX-1877 and KIN-806 enhanced macrophage and helper T lymphocyte infiltration for 3 weeks after drug treatment. TX-1877 shows a high EA value and has the C2 of HOMO localizing on N-methylamide and the C2 of LUMO localizing on 2-nitroimidazole group. The MO data might be useful for designing a bifunctional hypoxic cell radiosensitizer. TX-1877 and its analogues are potential antimetastatic hypoxic cell radiosensitizers, which would improve the efficiency of radiotherapy and quality of life in cancer treatment.

Animals↗
PubMed2001

Mapping peroxidase in plant tissues by scanning electrochemical microscopy.

Scanning electrochemical microscopy has been firstly used to map the enzymatic activity in natural plant tissues. The peroxidase (POD) was maintained in its original state in the celery (Apium graveolens L.) tissues and electrochemically visualized under its native environment. Ferrocenemethanol (FMA) was selected as a mediator to probe the POD in celery tissues based on the fact that POD catalyzed the oxidation of FMA by H(2)O(2) to increase FMA(+) concentration. Two-dimensional reduction current profiles for FMA(+) produced images indicating the distribution and activity of the POD at the surface of the celery tissues. These images showed that the POD was widely distributed in the celery tissues, and larger amounts were found in some special regions such as the center of celery stem and around some vascular bundles.

Apium↗
PubMed2001

Cytochrome P450s CYP6D3 and CYP6D1 are part of a P450 gene cluster on autosome 1 in the house fly.

The P450 monooxygenases of insects are important in the metabolism of numerous endogenous and exogenous compounds. However, identity of the P450 isoform(s) involved in these reactions is rarely known. A critical first step in the identification of important P450s is the cloning and sequencing of their genes. Toward this goal we report the genomic sequence of a new cytochrome P450, termed CYP6D3, from the house fly, Musca domestica. CYP6D3 is part of a P450 gene cluster located on chromosome 1 and is located upstream of a related gene, CYP6D1. The similar genetic structures of CYP6D3 and CYP6D1 (5 exons and 4 introns of similar length) suggest one of these genes may have been the result of a duplication event. The CYP6D3 deduced amino acid sequence indicates a protein with 518 amino acids and a molecular weight of 59.3 kDa. The CYP6D3 protein is most similar to house fly CYP6D1 (78%) and Cyp6D2 (56%) from Drosophila melanogaster. The deduced amino acid sequences of CYP6D3 and CYP6D1 are identical at the Helix I and heme binding regions.

Amino Acid Sequence↗
PubMed2001

Development of an automated method for detecting mammographic masses with a partial loss of region.

Recently, we have been developing several automated algorithms for detecting masses on mammograms. For our algorithm, we devised an adaptive thresholding technique for detecting masses, but our system failed to detect masses with a partial loss of region that were located on the edge of the film. This is a common issue in all of the algorithms developed so far by other groups. In order to deal with this problem, we propose a new method in the present study. The partial loss masses are identified by their similarity to a sector-form model in the template matching process. To calculate the similarity, four features are applied: 1) average pixel value; 2) standard deviation of pixel values; 3) standard correlation coefficient defined by the sector-form model; and 4) concentration feature determined from the density gradient. After employing the new method to 335 digitized mammograms, the detection sensitivity for the partial loss masses jumped from 70% to 90% when the number of false positives was kept constant (0.2/image). Moreover, a combination of the existing method and the new method improved the true-positive rate up to 97%. Such results indicate that the new technique may improve the performance of our computer-aided diagnosis system for mammographic masses effectively.

Algorithms↗
PubMed2001

Effect of ecabet sodium enema on mildly to moderately active ulcerative proctosigmoiditis: an open-label study.

OBJECTIVES: Ecabet sodium (ES), a nonabsorbable antigastric ulcer agent, has been shown to adhere to the region of an ulcer. It topically enhances gastric mucosal defensive factors such as the endogenous prostaglandins, capsaicin-sensitive sensory nerves, nitric oxide, and mucin. All of these mucosal defensive factors play an important role in maintaining the mucosal integrity of the colon and rectum. Therefore, we investigated the effect of ES in patients with mildly to moderately active ulcerative proctosigmoiditis. METHODS: In an open-label study, seven patients with mildly to moderately active ulcerative colitis (UC) who had an inflamed mucosa in the rectum and/or sigmoid and were resistant to 4-wk topical and systemic standard treatment were treated with an ES enema b.i.d. for 14 days. The enema consisted of ES (1 g) and tepid water (20 or 50 ml). These patients were assessed by the Clinical Activity Index, colonoscopically, and histologically before and after the ES therapy. The ES therapy was started after obtaining informed consent from the patients. RESULTS: Six of the seven patients responded to therapy and achieved clinical, endoscopic, and histological remissions. One patient was withdrawn because of increased stool frequency. All six patients who completed the study showed a significant change in the mean Clinical Activity Index score from 5.3+/-1.4 (mean +/- SD) to 0.5+/-0.8 (p < 0.05), in the colonoscopic score from 3.0+/-0.9 to 0.8+/-0.4 (p < 0.05), and in the histological score from 2.7+/-0.5 to 0.5+/-0.6 (p < 0.05), and achieved remission at the end of the study. There were no side effects attributable to the ES therapy. Five of the six patients are still in clinical remission after a median follow-up period of 5 months. CONCLUSIONS: The ES enemas proved to be a safe and potentially useful adjuvant therapy currently available for treating patients with mildly to moderately active ulcerative proctosigmoiditis. A controlled study is necessary to confirm our results.

Abietanes↗
PubMed2001

Development and characterization of 1C6-203, a new monoclonal antibody specific to human thymidine phosphorylase.

Thymidine phosphorylase (dThdPase) is an essential enzyme for activation of the oral cytostatic drug capecitabine and its intermediate metabolite, doxifluridine, to 5-fluorouracil in tumors. Methods to estimate dThdPase expression in tumor tissue might be useful to predict the efficacy of capecitabine and doxifluridine in cancer patients. We established a new monoclonal antibody (MAb), 1C6-203, applicable for dThdPase immunohistochemistry and compared its staining characteristics with those of a previously established MAb, 654-1. In 4% paraformaldehyde-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 19/30 and 9/30 patients, respectively. In 10% formalin-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 18/30 and 6/30 patients, respectively. In negative 10% formalin-fixed tissues, microwave treatment improved the positivity of 654-1-stained cancer cells. These results suggest that an epitope recognized by 1C6-203 is resistant to epitope masking by formaldehyde fixation, whereas that for MAb 654-1 is sensitive. Therefore, MAb 1C6-203 might be more suitable than MAb 654-1 for evaluating dThdPase expression in colorectal carcinoma.

Animals↗
PubMed2001

Chromosome 13 locus, Pbd2, regulates bone density in mice.

Bone density is inherited as a complex polygenic trait. Previously, we identified two quantitative trait loci (QTLs) specifying the peak relative bone mass (bone mass corrected by bone size) on chromosomes (Chrs) 11 and 13 by interval mapping in two mouse strains: SAMP2 and SAMP6. The latter strain is an established murine model of senile osteoporosis and exhibits a significantly lower peak relative bone mass than SAMP2 mice. In this study, we report the effects of the Chr 13 QTL on peak bone density (Pbd2). First, we constructed a congenic strain P6.P2-Pbd2b, which carried a single genomic interval from the Chr 13 of SAMP2 on an SAMP6-derived osteoporotic background, to dissect this polygenic trait into single gene factors. This congenic strain had a higher bone density than the background strain using three measurement methods with different principles for bone density. Next, we measured the peak relative bone mass of the AKR/J strain and the 13 senescence-accelerated mouse (SAM) strains, which are considered to be a series of recombinant-like inbred (RI) strains derived from the AKR/J strain and other unspecified strains. We then determined the microsatellite marker haplotypes of these strains around the Pbd2 locus, in which three strains with a high relative bone mass shared the same haplotype over the 26-centimorgan (cM) region. In the Pbd2 locus, a high relative bone mass was associated with alleles of the unknown strain, whereas a low relative bone mass was associated with the alleles from the AKR/J strain. These results confirmed the existence of a Pbd2 locus regulating bone density in the SAM strains.

Alleles↗
PubMed2001

Prognostic significance of the labeling of Adnab-9 in pancreatic intraductal papillary mucinous neoplasms.

BACKGROUND: Pancreatic intraductal papillary mucinous neoplasms (IPMN), morphologically resembling colonic adenomas, often have an indefinable malignant potential. We used a monoclonal antibody (MAb) raised against colonic adenomas, Adnab-9, to identify patients with a better prognosis. METHODS: We assessed Adnab-9-labeled sections of these neoplasms from 50 patients, 13 pancreatic adenocarcinomas, and 32 colonic adenomas using standard immunohistochemical techniques. RESULTS: 26% of the IPMNs labeled with Adnab-9 as compared to 0% of pancreatic ductal cancers or surrounding benign tissues, (p < 0.001) and 53% of adenomas (p < 0.025). Labeling in IPMNs was usually seen in the noninvasive epithelium suggesting that Adnab-9 is a premalignant marker in these lesions. Labeling of invasive IPMN's identified a group of patients with a superior overall survival (p = 0.027). CONCLUSION: Adnab-9 labeling-characteristics appear similar for both IPMNs and adenomatous polyps, suggesting that they are analogous lesions. Adnab-9 labeling may also be a useful prognostic marker for invasive intraductal papillary mucinous neoplasms.

Adenocarcinoma, Mucinous↗
PubMed2001

[Health status and lifestyle issues of homeless people in Sapporo city, 2000].

OBJECTIVE: To clarify the health status and lifestyle issues of homeless people in Sapporo city, voluntary "health consultations and medical examinations" were carried out near an emergency kitchen. METHODS: The voluntary activities were held in a park near the shelter tents of homeless people seven times from December 1999 to December 2000. The homeless people who consulted us, medical doctors, were asked detailed questions about past history, present illness, subjective symptoms, lifestyles and so on, and were examined for their blood pressure and urinary parameter. RESULTS: A total of 60 homeless people, including 59 men and 1 woman, were consulted and examined, Fifty-seven percent of them were 50 years old of older, and 30% had been homeless for less than half a year. Forty percent had some dental problems, 28% suffered neck stiffness, and 27% back pain. The medical examination found 53% of them to be hypertensive and 26% to be diabetic. Twenty-five percent had meals only once a day, 55% had meat or fish in their diet not more than twice a week and 57% had vegetables in their diet not more than twice a week. Forty-two percent slept not more than 5 hours a day, 13% often drank alcohol in the daytime, and 83% were smokers. CONCLUSION: The present results suggest that lifestyle-related chronic diseases are more significant problems among homeless people in Sapporo city than common infectious diseases such as tuberculosis or dysentery, probably because it is colder and therefore there are fewer homeless people in Sapporo city than in other major cities in Japan such as Tokyo and Osaka. Further studies of the homeless people living in such a cold environment are warranted to develop better health policies for them in the context of their social and economical determinants. In addition, it is important to establish a more reliable registration system for these people in order to plan and provide a comprehensive social and health support network as needed.

Adult↗