Search PubMed⌕ Search

Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 289 records · Page 16Linked to original sources
PubMed1999

Acetylcholine-induced membrane potential changes in endothelial cells of rabbit aortic valve.

1. Using a microelectrode technique, acetylcholine (ACh)-induced membrane potential changes were characterized using various types of inhibitors of K+ and Cl- channels in rabbit aortic valve endothelial cells (RAVEC). 2. ACh produced transient then sustained membrane hyperpolarizations. Withdrawal of ACh evoked a transient depolarization. 3. High K+ blocked and low K+ potentiated the two ACh-induced hyperpolarizations. Charybdotoxin (ChTX) attenuated the ACh-induced transient and sustained hyperpolarizations; apamin inhibited only the sustained hyperpolarization. In the combined presence of ChTX and apamin, ACh produced a depolarization. 4. In Ca2+-free solution or in the presence of Co2+ or Ni2+, ACh produced a transient hyperpolarization followed by a depolarization. In BAPTA-AM-treated cells, ACh produced only a depolarization. 5. A low concentration of A23187 attenuated the ACh-induced transient, but not the sustained, hyperpolarization. In the presence of cyclopiazonic acid, the hyperpolarization induced by ACh was maintained after ACh removal; this maintained hyperpolarization was blocked by Co2+. 6. Both NPPB and hypertonic solution inhibited the membrane depolarization seen after ACh washout. Bumetanide also attenuated this depolarization. 7. It is concluded that in RAVEC, ACh produces a two-component hyperpolarization followed by a depolarization. It is suggested that ACh-induced Ca2+ release from the storage sites causes a transient hyperpolarization due to activation of ChTX-sensitive K+ channels and that ACh-activated Ca2+ influx causes a sustained hyperpolarization by activating both ChTX- and apamin-sensitive K+ channels. Both volume-sensitive Cl- channels and the Na+-K+-Cl- cotransporter probably contribute to the ACh-induced depolarization.

Acetylcholine↗
PubMed1999

Human papillomavirus types 16 and 39 in a vulval carcinoma occurring in a woman with Hailey-Hailey disease.

A woman with Hailey-Hailey disease, suffering from carcinoma of the vulva, was examined by histology and for the presence of human papillomavirus (HPV) DNA by polymerase chain reaction (PCR) and in situ hybridization. Our diagnosis by histological examination revealed the vulval carcinoma to be a squamous cell carcinoma (SCC), adjacent to lesions of Hailey-Hailey disease and severe dysplasia/carcinoma in situ [vulval intraepithelial neoplasia (VIN) III]. The PCR with consensus primers for the L1 region (L1-PCR) successfully amplified HPV DNA using total DNA extracted from formalin-fixed and paraffin-embedded tissue specimens. Restriction fragment length polymorphism analysis and sequencing of L1-PCR products revealed HPV types 16 and 39. HPV 16-specific primers for the E6 region identified HPV 16 DNA. In situ hybridization analysis with biotinylated HPV 16 and 39 DNA probes revealed the presence of the HPV 39 genome in the nuclei of the tumour cells in the SCC. These results indicate that HPV 16 and 39 are associated with lesions in vulval carcinoma. Regarding the patient's susceptibility to infection in the case of Hailey-Hailey disease, there is a possibility that HPV was inoculated into the lesions of Hailey-Hailey disease and induced those of VIN III and SCC.

Aged↗
PubMed1999

Metabolism and functional effects of sphingolipids in blood cells.

We examined the sphingolipid metabolism of peripheral blood cells, i. e. platelets, erythrocytes, neutrophils and mononuclear cells. A distinguishing characteristic of sphingolipid metabolism in these highly differentiated cells was their high sphingosine (Sph) kinase activity. The occurrence of [3H]sphingosine 1-phosphate (Sph-1-P) from [3H]Sph (actively incorporated from the outside) in the blood cells was strong, long-lasting, and independent of cell activation. Hence, the possibility of Sph-1-P playing a second messenger role is remote in these cells. About 40% of platelet Sph-1-P could be released extracellularly by 12-O-tetradecanoylphorbol 13-acetate, possibly through mediation by protein kinase C. On the other hand, in erythrocytes, neutrophils and mononuclear cells a significant percentage of Sph-1-P formed inside the cell was discharged without stimulation, whereas the stimulation-dependent release was marginal. In contrast to active [3H]Sph conversion to [3H]Sph-1-P, formation of [3H]sphingomyelin was barely detectable in the blood cells; this was especially true for anucleate platelets and erythrocytes. The Sph --> Sph-1-P pathway may become predominant over the Sph --> Cer --> sphingomyelin pathway during late-stage differentiation into platelets or erythrocytes. Sph and its methylated derivative, N, N-dimethylsphingosine, induced apoptosis not only in neutrophils but also in mononuclear cells, whereas Sph-1-P elicited Ca2+ mobilization in platelets. Our results suggest that all blood cells may remove plasma Sph, which is harmful or suppressive to cellular functions, and change it into Sph-1-P, acting as the source of plasma Sph-1-P, which may play a variety of important roles in blood vessels.

Apoptosis↗
PubMed1999

CagA and cytotoxicity of Helicobacter pylori are not markers of peptic ulcer in Japanese patients.

BACKGROUND: The infection with cagA-positive Helicobacter pylori strains is reported to be associated with peptic ulcer disease in developed countries, but it is controversial in Asia. To investigate the relationship between the virulence factors of H. pylori and peptic ulcer disease in Japan, we compared these between ulcer and nonulcer patients. MATERIALS AND METHODS: Seventy-four strains of clinically isolated H. pylori obtained from 22 gastric ulcer (GU), 23 duodenal ulcer (DU), and 29 chronic gastritis (CG) patients were studied. The presence of vacA and cagA gene was examined by polymerase chain reaction method using two different primer sets. We evaluated the proliferation-inhibiting and lethal cytotoxicity of culture supernatants using the alamarBlue assay. RESULTS: The vacA gene was identified in all strains by the original primers. S1 strains were found in 90.9% (20/22) from GU, 95.7% (22/23) from DU, and 96.6% (28/29) from CG patients. The prevalence of cagA gene determined by the first, and second primers was 90.9% (20/22), 90.9% (20/22) in strains from GU, 87.0% (20/23), 91.3% (21/23) from DU, and 86.2% (25/29), 89.7% (26/29) from CG patients, respectively. The supernatant showed cytolethal effect in 95.5% (21/22) of strains from GU, in 100% (23/23) from DU, and in 93.1% (27/29) from CG patients. There was no significant difference in the prevalence of the virulence factors between H. pylori strains isolated from patients with peptic ulcers and those with chronic gastritis. CONCLUSIONS: These results indicate that cagA gene status and the proliferation-inhibiting and lethal cytotoxicity of supernatant are not reliable markers of ulcerogenicity of H. pylori in Japanese patients.

Adolescent↗
PubMed1999

A cephalometric study of the relationship between the level of velopharyngeal closure and the palatal plane in patients with repaired cleft palate and controls without clefts.

To find out whether the palatal plane is a useful indicator for evaluating the level of velopharyngeal closure, we did a cross-sectional study from early childhood to puberty of the vertical relationship between the palatal plane and the level of velarpharyngeal contact during velopharyngeal functioning in 61 patients with repaired cleft palate (unilateral cleft lip and palate = cleft group) and 82 controls without clefts (control group). Measurements on the vertical dimension were derived from a coordinate system and landmarks on lateral cephalograms, and the significance of differences in measurements was analysed using Student's t-test. Changes in the points of velarpharyngeal contact in relation to the palatal plane with growth showed a consistent tendency though differed between the two groups. In the control group, the PPW (point where palatal plane extension intersects the posterior pharyngeal wall) was maintained at a level that did not differ significantly from the level of midpoint of velarpharyngeal contact during phonation of /a/, and was maintained at a level that did not differ significantly from the level of the inferior point of velarpharyngeal contact. In the cleft group, however, it was maintained at a level that was slightly higher than the superior point of velarpharyngeal contact both during phonation of /a/ and during blowing. These results suggest that the palatal plane is useful as an indicator for evaluating the level of velopharyngeal closure.

Adolescent↗
PubMed1999

A cephalometric study of the stability of the base of the pharyngeal flap following a modified 'unified velopharyngoplasty procedure'.

A cephalometric study was conducted on 12 patients with repaired cleft palate to evaluate the stability in level and length of the base attachment of the velopharyngeal complex following pharyngeal flap surgery by a modified velopharyngoplasty. Complete velopharyngeal closure and normal articulation with a speech appliance were confirmed in all patients prior to pharyngeal flap surgery, which was performed on patients 10 years of age and above. Cephalometric radiographs were taken immediately, 1 year, 2 years and 3 years postoperatively. Cephalometric analysis revealed that although the level and length of the base of the velopharyngeal complex showed changes during the first postoperative year, they remained stable when compared with the palatal plane during the last two years. This indicated therefore that the base of a velopharyngoplasty should be attached at the same level of the palatal plane, namely the level of velopharyngeal closure, and that the procedure appeared useful in producing a stable velopharyngeal complex.

Adolescent↗
PubMed1999

Function of the propeptide region in recombinant expression of active procathepsin L in Escherichia coli.

In order to determine the functional role of the procathepsin L propeptide region for the preparation of active recombinant rat cathepsin L (CL), cDNAs encoding two short-length propeptides (C-terminal 2 and 27 residues) and the full-length (96 residues) one plus the entire CL were expressed as two soluble fusion proteins with a fragment of maltose-binding protein and an insoluble fusion protein with glutathione-S-transferase in Escherichia coli, respectively. After refolding of the insoluble fusion protein, each gene product was purified to homogeneity by amylose or glutathione-Sepharose-4B affinity column, and digestion with factor Xa and alpha-thrombin under alkaline conditions (pH approximately 8.0) led to the elution of two pure short-length procathepsin Ls (PCLs) and a full-length one, respectively. The enzymatic activity, estimated by hydrolytic assaying of benzoxycarbonyl-Phe-Arg-7-(4-methyl)coumarylamide under acidic conditions (pH 5.5), indicated that the two short-length PCLs exhibited in a great loss of the activity, as compared with the full-length PCL. The CD spectra of the short-length PCLs were different from that of the full-length one. The present results clearly show that the full-length propeptide is essential for construction of the active tertiary structure of CL at the stage of recombinant protein expression, although the expression of CL itself in E. coli does not require the propeptide. Based on the tertiary structure of PCL, the propeptide region necessary for the construction of the CL active structure has been discussed.

Animals↗
PubMed1999

Sphingosine 1-phosphate formation and intracellular Ca2+ mobilization in human platelets: evaluation with sphingosine kinase inhibitors.

Sphingosine 1-phosphate (Sph-1-P) is considered to play a dual role in cellular signaling, acting intercellularly as well as intracellularly. In this study, we examined the role of Sph-1-P as a signaling molecule in human platelets, using DL-threo-dihydrosphingosine (DHS) and N,N-dimethylsphingosine (DMS), inhibitors of Sph kinase and protein kinase C. Both DMS and DL-threo-DHS were confirmed to be competitive inhibitors of Sph kinase obtained from platelet cytoplasmic fractions. In intact platelets labeled with [3H]Sph, stimulation with 12-O-tetradecanoylphorbol 13-acetate or thrombin did not affect [3H]-Sph-1-P formation. While both DMS and DL-threo-DHS inhibited not only [3H]Sph-1-P formation but also protein kinase C-dependent platelet aggregation, staurosporine, a potent protein kinase inhibitor, only inhibited the protein kinase C-dependent reaction. Hence, it is unlikely that Sph kinase activation and the resultant Sph-1-P formation are mediated by protein kinase C in platelets. Furthermore, Ca2+ mobilization induced by platelet agonists that act on G protein-coupled receptor was not affected by DMS or DL-threo-DHS. Our results suggest that Sph-1-P does not mediate intracellular signaling, including Ca2+ mobilization, in platelets.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1999

Does the Murphy eye reduce the reliability of chest auscultation in detecting endobronchial intubation?

UNLABELLED: Bilateral breath sounds are routinely auscultated after endotracheal intubation to verify that the endotracheal tube (ETT) tip is properly positioned. We conducted the present study to ascertain whether the eye of the Murphy tube has an influence on the reliability of auscultation of breath sounds in detecting endobronchial intubation. Twenty patients undergoing scheduled oral and maxillofacial surgery participated in this study. After the induction of general anesthesia, either the Magill tube or the Murphy tube was inserted through the nose into the trachea. The fiberoptic bronchoscope was inserted through the ETT, and the distance from the nares to the carina of the trachea was measured. When breath sounds from the left side of the chest changed and disappeared while the ETT was being advanced, the distance from the nares to the ETT tip was measured. Unilateral auscultatory change was not observed until the ETT tip was advanced beyond the carina and inserted 1.5+/-0.4 cm into the right mainstem bronchus when the Magill tube was used and 2.0+/-0.4 cm when the Murphy tube was used (P < 0.01). Breath sounds disappeared when the ETT tip was further advanced up to 3.2+/-0.3 cm from the carina. We demonstrated that the eye of the Murphy tube reduces the reliability of chest auscultation in detecting endobronchial intubation. IMPLICATIONS: The Murphy eye was designed to allow ventilation of the lung when the bevel of the endotracheal tube is occluded. We demonstrated that the eye of the Murphy tube reduces the reliability of chest auscultation in detecting endobronchial intubation.

Adult↗
PubMed1999

Differentiation of small solitary pulmonary nodules using Tc-99m MIBI and Tl-201 SPECT

The authors evaluated the ability of dual SPECT with Tc-99m MIBI and Tl-201 chloride to differentiate malignant and benign solitary pulmonary nodules smaller than 3 cm in diameter. Forty-three patients had solitary pulmonary nodules smaller than 3 cm in diameter based on the findings of chest CT. All patients underwent dual-isotope SPECT with Tc-99m MIBI and Tl-201 chloride. Regions of interest were placed over the tumors (T) and contralateral normal lung tissue (N) on one coronal SPECT view, and T:N ratios and retention indices were calculated. The sensitivities of early and delayed Tc-99m MIBI SPECT and early and delayed Tl-201 chloride SPECT for differentiating malignant and benign lesions were 44%, 48%, 56%, and 52%, respectively. The corresponding specificity rates were 44%, 56%, 25%, and 31%, respectively, and corresponding accuracy rates were 44%, 51%, 44%, and 44%, respectively. There were no statistically significant differences between malignant and benign lesions in the early and delayed T:N ratios for Tc-99m MIBI and Tl-201 chloride and the retention index for Tc-99m MIBI. However, the retention index using Tl-201 chloride in malignant lesions was significantly higher (P < 0.01) than that in benign lesions. Analysis of semiquantitative parameters of the T:N ratio and retention index from Tc-99m MIBI SPECT appears to have little or no value for differentiating malignant from benign solitary pulmonary nodules smaller than 3 cm in diameter. However, the retention index using Tl-201 chloride seems to be a better parameter for differentiating between these malignant and benign lesions.

Journal Article↗
PubMed1999

Nitric oxide-dependent vasodilator mechanism is not impaired by hypertension but is diminished with aging in the rat aorta.

This study was designed to elucidate the effects of hypertension and aging on nitric oxide (NO)-mediated relaxation response to acetylcholine in the rat aorta. NO-mediated relaxation response was assessed as the relaxation response to acetylcholine after treatment with cyclooxygenase inhibitor in KCl-precontracted aortic rings. The endothelium-dependent relaxation responses to acetylcholine were lower in aortic rings isolated from spontaneously hypertensive rats (SHRs) at ages 16-20 and 55-60 weeks compared with those seen in age-matched Wistar-Kyoto (WKY) rats. Aging induced a reduction of the relaxation response to acetylcholine in aortic rings from WKY rats but not from SHRs. Pretreatment with indomethacin enhanced the relaxation response to acetylcholine in only SHRs at ages 16-20 and 55-60 weeks, thereby cancelling the difference in the relaxation response between WKY rats and SHRs. Simultaneous administration of indomethacin and NG-nitro-L-arginine methyl ester abolished the relaxation response to acetylcholine in both strains. Thus NO-mediated relaxation response to acetylcholine was similar between WKY rats and SHRs at ages 16-20 and 55-60 weeks, respectively, and was attenuated with aging to the same degree in both strains. In conclusion, NO-mediated relaxation response to acetylcholine in the aorta is attenuated with aging but not impaired by hypertension.

Acetylcholine↗
PubMed1999

Fas ligand is frequently expressed in human pancreatic duct cell carcinoma.

Fas ligand (Fas-L) is a key molecule in normal immune development, homeostasis, modulation, and function. Recent reports suggested that tumor cells can evade immune attack by killing lymphocytes through expressing Fas-L on the tumor cell surface. The expression of Fas-L has been demonstrated in pancreatic cancer cell lines and in tissues. The messenger RNA (mRNA) and protein expression of Fas-L was investigated in four pancreatic cancer cell lines and 19 human pancreatic duct cell carcinomas (PDCs) by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. In addition, coculture assay of Fas-L and Fas-expressing PANC-1 cells and Fas-sensitive Jurkat cells was performed. Fas-L mRNA expression was observed in all four cell lines as well as in 10 PDC tissues, and the protein expression was frequently detected in the PDC tissues (16 of 19 cases). The coculture experiments showed that PANC-1 cells induced apoptosis of Jurkat cells, whereas the PANC-1 cells themselves and Jurkat cells cultured without the presence of PANC-1 showed few apoptotic changes. These findings suggest that Fas-L may play an important role in the ability of PDCs to escape from immune surveillance through the induction of apoptosis in tumor-attacking lymphocytes. The frequent expression of Fas-L in PDCs may partly explain the notorious biologic behavior of PDCs.

Apoptosis↗
PubMed1999

Inhibition of experimental metastasis of human fibrosarcoma cells by anti-recombinant 37-kDa laminin binding protein antibody.

The laminin binding protein of 37 kDa (37LBP) is regarded as a precursor protein of the high-affinity 67-kDa laminin receptor (67LR). Expression of 67LR/37LBP is well correlated with biological aggressiveness of cancer, particularly with invasive and metastatic potential. To investigate in detail the role of 37LBP in cancer cells, we synthesized recombinant 37LBP (r37LBP) as a fusion protein and generated an IgG-type polyclonal antibody P4G against r37LBP. Western blot analysis with P4G showed a single band of 67LR under both nonreducing and reducing conditions using cell extract of human fibrosarcoma cells HT1080. It was shown that P4G inhibited cell attachment to immobilized laminin in a dose-dependent manner. Further, the intravenous injection of HT1080 cells pretreated with P4G, compared with that of cells pretreated with normal rabbit serum, resulted in a reduced number of experimental metastases (3.3+/-5.1 vs. 58.0+/-38.0 nodules per mouse, respectively) (P<0.005). These results suggest that P4G inhibits the colonization and growth of HT1080 cells in the lungs of mice, and that the blocking of r37LBP with the specific antibody P4G may offer a potential strategy for preventing cancer metastasis.

Amino Acid Sequence↗
PubMed1999

Recurrent subcutaneous abscess of the sternal region in ulcerative colitis.

An 18-yr-old female patient with extensive ulcerative colitis suffered from several episodes of recurrent aseptic subcutaneous abscesses of the sternal region with a course paralleling that of her colitis. The abscess seemed to occur secondarily to osteomyelitis of the sternum, which is a manifestation of the synovitis, acne, pustulosis, hyperostosis, and osteomyelitis (SAPHO) syndrome.

Abscess↗