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S Inada

Publications and source records attributed to S Inada.

At least 19 recordsLinked to original sources
PubMed2006

Connexins in the sinoatrial and atrioventricular nodes.

The sinoatrial node (SAN) and the atrioventricular node (AVN) are specialized tissues in the heart: the SAN is specialized for pacemaking (it is the pacemaker of the heart), whereas the AVN is specialized for slow conduction of the action potential (to introduce a delay between atrial and ventricular activation during the cardiac cycle). These functions have special requirements regarding electrical coupling and, therefore, expression of connexin isoforms. Electrical coupling in the center of the SAN should be weak to protect it from the inhibitory electrotonic influence of the more hyperpolarized non-pacemaking atrial muscle surrounding the SAN. However, for the SAN to be able to drive the atrial muscle, electrical coupling should be strong in the periphery of the SAN. Consistent with this, in the center of the SAN there is no expression of Cx43 (the principal connexin of the working myocardium) and little expression of Cx40, but there is expression of Cx45 and Cx30.2, whereas in the periphery of the SAN Cx43 as well Cx45 is expressed. In the AVN, there is a similar pattern of expression of connexins as in the center of the SAN and this is likely to be in large part responsible for the slow conduction of the action potential.

Action Potentials↗
PubMed2003

Sarcoplasmic reticulum Ca2+ release is not a dominating factor in sinoatrial node pacemaker activity.

Recent work on isolated sinoatrial node cells from rabbit has suggested that sarcoplasmic reticulum Ca2+ release plays a dominant role in the pacemaker potential, and ryanodine at a high concentration (30 micromol/L blocks sarcoplasmic reticulum Ca2+ release) abolishes pacemaking and at a lower concentration abolishes the chronotropic effect of beta-adrenergic stimulation. The aim of the present study was to test this hypothesis in the intact sinoatrial node of the rabbit. Spontaneous activity and the pattern of activation were recorded using a grid of 120 pairs of extracellular electrodes. Ryanodine 30 micromol/L did not abolish spontaneous activity or shift the position of the leading pacemaker site, although it slowed the spontaneous rate by 18.9+/-2.5% (n=6). After ryanodine treatment, beta-adrenergic stimulation still resulted in a substantial chronotropic effect (0.3 micromol/L isoproterenol increased spontaneous rate by 52.6+/-10.5%, n=5). In isolated sinoatrial node cells from rabbit, 30 micromol/L ryanodine slowed spontaneous rate by 21.5+/-2.6% (n=13). It is concluded that sarcoplasmic reticulum Ca2+ release does not play a dominating role in pacemaking in the sinoatrial node. The full text of this article is available at http://www.circresaha.org.

Action Potentials↗
PubMed2001

A novel single-nucleotide polymorphism at the 5'-flanking region of SAA1 associated with risk of type AA amyloidosis secondary to rheumatoid arthritis.

OBJECTIVE: To address whether the gamma haplotype at exon 3 of the SAA1 gene is directly associated with type AA amyloidosis or is merely in linkage with an unknown polymorphism that is primarily associated with disease risk, we examined the SAA1 gene for new polymorphisms. METHODS: We analyzed DNA samples from 44 rheumatoid arthritis (RA) patients with AA amyloidosis (amyloid group), 55 RA patients without AA amyloidosis (RA group), and 58 non-RA healthy subjects (non-RA group). We also examined DNA samples from 50 Caucasians to compare linkage disequilibrium relationships involving SAA1 region polymorphisms between Japanese and Caucasoid populations. RESULTS: We observed 3 novel single-nucleotide polymorphisms (SNPs) in the 5'-flanking region of SAA1: -61C/G, -13T/C, and -2G/A. Comparison of allele frequencies and ratios of individuals with particular alleles between the study groups revealed statistically significant differences between the amyloid and RA groups and between the amyloid and non-RA groups. Statistical analysis revealed that the -13T/C SNP was strongly associated with AA amyloidosis. In addition, we found tight linkage between the -13T allele and the alpha haplotype, rather than the beta haplotype, at exon 3 in the Caucasoid population, while -13T was closely linked to the gamma and beta haplotypes, rather than the alpha haplotype, in the Japanese population. Since the linkage disequilibrium relationship was reversed between the Japanese and Caucasoid populations, different exon 3 haplotypes of SAA1 are found to be associated with the risk of AA amyloidosis in different ethnic groups. CONCLUSION: Our data suggest that the SAA1 -13T allele, rather than SAA1 exon 3 haplotypes, is primarily associated with AA amyloidosis risk.

Amyloidosis↗
PubMed2001

Survey of antibiotic resistance in Pseudomonas aeruginosa by The Tokyo Johoku Association of Pseudomonas Studies.

Pseudomonas aeruginosa resistance (minimum inhibitory concentration [MIC], > or =16 microg/ml defined as resistant) to meropenem, imipenem, panipenem, piperacillin, ceftazidime, cefozopran, cefoperazone, sulbactam/cefoperazone, amikacin, and tobramycin, as well as cross-resistance profiles, were investigated in P. aeruginosa strains isolated at eight hospitals in the Johoku area, Tokyo, during November 1998. Overall, 8.3% of isolates were imipenem-resistant and 4.6% were ceftazidime-resistant. However, the incidence of antibiotic-resistant P. aeruginosa was distinctly different at each hospital. P. aeruginosa resistance to imipenem ranged from (MIC) 1 to 64 microg/ml (MIC90 32 microg/ml), and its resistance to ceftazidime ranged from 2 to more than 128 microg/ml (MIC90, 64 microg/ml). Meropenem (MIC range, < or =0.25 to 16 microg/ml) was more active than panipenem (MIC range, 2 to 64 microg/ml). Cefozopran was more active than piperacillin, cefoperazone, or sulbactam/cefoperazone, but many strains were resistant to cefoperazone (17/57). Our analysis found cross-resistance to many beta-lactams, but the degree of cross-resistance was very variable.

Anti-Bacterial Agents↗
PubMed2001

Humoral immune-mediated acute, antigen-induced arthritis in rats is suppressed by the inducing antigen administered orally before, but not after, immunization.

Acute ovalbumin-induced arthritis (OIA), which is mediated by Arthus reaction to ovalbumin (OVA) in the joint space, can be induced by immunization of rats with OVA followed by the intraarticular injection of OVA. Because oral administration of antigen induces immunological unresponsiveness, we studied for the first time the effects of oral administration of OVA on acute OIA. The oral administration of OVA before immunization significantly suppressed the development of acute OIA, in accordance with decreases in both the anti-OVA IgG antibody production and in vitro lymphocyte proliferative responses to OVA. However, the oral administration of OVA after immunization did not show any decrease in antibody production or in vitro lymphocyte proliferation to OVA, or in the severity of acute OIA. These results indicate that the induction of oral tolerance to OVA in OIA is possible by oral administration of OVA before, but not after, immunization with the antigen. This supports the concept of using antigen feeding as a treatment for certain humoral immune-mediated diseases.

Acute Disease↗
PubMed2001

Involvement of cortical microtubules in plastic extension regulated by gibberellin in Lemna minor root.

We aimed to analyze the rheological characteristics during elongation of the root segments in Lemna minor. The elastic component of segment elongation (EC) increased for the first 6 h, and then almost stopped. However, the plastic component of the segment elongation (PC) began to rapidly increase from 6 h onwards. Uniconazole-P, a gibberellin biosynthesis inhibitor, inhibited the total elongation of root segments (TE), and this inhibition was mainly caused by suppression of the rapid increase in the PC after 6 h. Concomitant with this inhibition, the cortical microtubule (CMT) array within root epidermal cells became disorganized in the presence of uniconazole-P from 6 h onwards. Adding GA3 abolished the inhibition of TE by uniconazole-P treatment, and this recovery was caused not by the increase in the EC but by an increase in the PC. Furthermore, the CMT arrays also recovered their characteristic organization in the presence of GA3. These findings suggest that endogenous gibberellin accelerates TE by activating the PC via control of CMT arrays. This conclusion is also supported by rheological analysis where propyzamide was used to disrupt microtubules. We suggest that endogenous gibberellin controls the PC via its influence over the transverse arrangement of CMTs.

Benzamides↗
PubMed2001

Pacemaker shift in the rabbit sinoatrial node in response to vagal nerve stimulation.

Effects of brief postganglionic vagal nerve stimulation on the activation sequence of the rabbit sinoatrial (SA) node were investigated. Activation sequences in a small area (7 mm x 7 mm) on the epicardial surface were measured in a beat-to-beat manner using an extracellular potential mapping system composed of 64 modified bipolar electrodes with high-gain and low-frequency band-pass filtering. The leading pacemaker site was recognised clearly from both the activation sequence and the characteristic morphology of the potentials. Vagal stimulation resulted in a short-lasting initial slowing of spontaneous rate followed by a long-lasting secondary slowing; a brief period of relative or absolute acceleration was interposed between the two slowing phases. During these changes of spontaneous rate, the leading pacemaker site shifted in a complex beat-to-beat manner by 1-6 mm alongside the crista terminalis in the superior or inferior direction. For the first spontaneous excitation following stimulation, the greater the slowing, the larger the distance of the pacemaker shift. There was no such linear relationship between the extent of slowing and the distance of pacemaker shift for the subsequent beats. These changes in the leading pacemaker site in response to vagal stimulation may be the result of the functional and morphological heterogeneity of the mammalian SA node in terms of innervation, receptor distribution and ion channel densities. Experimental Physiology (2001) 86.2, 177-184.

Animals↗
PubMed2001

[A case of disseminated intravascular coagulopathy (DIC) and multiple organ failure (MOF) after ingestion of hydrochloric acid].

Ingestion of caustic materials causes systemic damages and requires treatment in an intensive care unit. This report presents a case of disseminated intravascular coagulopathy (DIC) and multiple organ failure after ingestion of hydrochloric acid in an attempted suicide. The patient was admitted to the emergency ward within 1 hr after ingestion of 60 ml of 35% hydrochloric acid. Initial blood examination suggested hemolysis without anemia or thrombocytopenia. Arterial blood gas analysis exhibited evident metabolic acidosis with hypoxia. Two hours after ingestion, severe hemolysis, anemia, thrombocytopenia emerged with abnormal results from clotting and fiblinolysis tests, and a diagnosis of DIC was made. Subsequently, conjugate deviation and severe bleeding diathesis appeared. No evidence for gastrointestinal bleeding and brain hemorrhage was obtained in our abdominal echography and brain computed tomography, respectively. In spite of vigorous suppurative therapy including transfusion of blood, fresh frozen plasma, and catecholamines, the patient expired 29 hrs after ingestion. Autopsy was not carried out. Rapid progressive DIC as an acute complication of acid ingestion must be born in mind.

Acidosis↗
PubMed2000

Regulation of root growth by gibberellin in Lemna minor.

Hormonal control of root growth was studied in Lemna minor. Although addition of gibberellic acid (GA3) to the culture medium did not promote the root growth, a gibberellin biosynthesis inhibitor, uniconazole P (Un-P), significantly inhibited root growth. Both length and diameter of roots in Un-P-treated plants were significantly smaller than those in control plants, mainly caused by inhibition of cell division. In epidermal cells, the length was slightly decreased and the width increased by Un-P treatment, indicating inhibition of elongation growth. GA3 completely nullified the inhibition caused by Un-P. Transverse cortical microtubules (CMTs) of epidermal cells in the elongation zone were significantly fragmented by treatment with Un-P, but not by that in the presence of GA3. The cellulose microfibril array in the Un-P-treated cells was more random and more oblique than that in the control cells. These results suggested that root growth in L. minor is regulated by endogenous gibberellin.

Gibberellins↗
PubMed2000

Regulation of elongation growth by gibberellin in root segments of Lemna minor.

Hormonal control of elongation growth was analyzed in segments excised from the elongation zone of Lemna roots. Exogenous GA3 did not promote the segment elongation but rather inhibited it. Uniconazole-P, a gibberellin biosynthesis inhibitor, significantly inhibited the segment elongation, and the inhibitory effect was completely nullified by GA3. In the epidermis, cell elongation was inhibited, but lateral cell expansion was not affected by uniconazole-P. Orientation of cortical microtubules of epidermal cells was disturbed by treatment with uniconazole-P for 12 h, and the disorganization of cortical microtubules was ameliorated by GA3. These findings suggested that disorganization of cortical microtubules induced inhibition of elongation growth of root. However, stabilization of cortical microtubules by taxol, a microtubule-stabilizing agent, did not affect the inhibition of segment elongation by uniconazole-P. These results suggested that endogenous gibberellin controls the elongation growth of root by regulating cell elongation.

Cell Size↗
PubMed2000

[Hypersensitivity peumonitis in a patient with rheumatoid arthritis].

We report a case with rheumatoid arthritis and hypersensitivity pneumonitis. A 66-year-old female was admitted to our hospital because of fever, cough, and progressive dyspnea on October 10, 1997. She had a history of rheumatoid arthritis from 1987 and was treated with cyclophosphamide when she developed pulmonary symptoms in September 1997. On admission arthritis was subsided. Fine crackles on ausculation of lung, hypoxia, ground-glass appearance on chest X-ray were detected. The computed tomography of the chest disclosed diffuse interstitial shadow with patchy destruction of alveolar structures. Bronchoalveolar lavage demonstrated an increase in lymphocytes with predominance of suppressor-cytotoxic T cell subset (CD 8+). The histopathological examination of transbronchial lung biopsy showed interstitial inflammation with marked predominance of lymphocyte with intraalveolar exudate. Her condition got better and she discharged without definitive diagnosis and treatment for her respiratory symptoms. Eight hours after she went back home, she suddenly presented high fever and cough and gradually developed dyspnea. She was readmitted 5 days after the previous discharge. Although no specific precipitin antibody against various microorganisms was detected in her sera, the diagnosis of hypersensitivity pneumonitis was made. Thirty mg per day of prednisolone was resolved her symptoms promptly. There was no reported case with hypersensitivity pneumonitis and rheumatoid arthritis of other collagen diseases. The clinical course that arthritis and pulmonary symptoms appeared alternatively is of considerable interest to investigate for the pathogenesis of these two immune disorders.

Aged↗
PubMed2000

[Utility of Ringer's acetate solution as an intraoperative fluid during cardiovascular surgery with cardiopulmonary bypass].

This study aimed to clarify the difference in the effects of Ringer's acetate (AR) and Ringer's lactate (LR) administration during cardiovascular surgery with cardiopulmonary bypass. We evaluated their effects on intra and postoperative metabolism, liver functions, blood gas and hemodynamic states. Twenty patients were divided into two groups; AR group (n = 10) and LR group (n = 10). Intraoperative serum D-lactate levels in LR group were significantly higher than those in AR group from the beginning of the operation to awakening. Serum acetate levels showed no increase in both groups. The arterial ketone body ratio (AKBR) in AR group was higher than that in LR group, but the difference was not significant. Serum glutamic pyruvic transaminase (GPT) and alkaline phosphatase (ALP) levels in LR group were significantly higher than those in AR group from the induction of the anesthesia. It has been reported that acetate has a greater vasodialatory effect than lactate. However, our findings indicate no significant difference in hemodynamics between the two groups. These results suggest that AR may be more useful than LR during cardiovascular surgery with cardiopulmonary bypass.

Adult↗
PubMed2000

CTLA-4 gene polymorphism in Japanese patients with rheumatoid arthritis.

OBJECTIVE: To examine whether CTLA-4 gene confers susceptibility to rheumatoid arthritis (RA) in Japanese. METHODS: We investigated the distribution of a CTLA-4 gene polymorphism in 85 Japanese patients with RA and 200 controls. An A/G transition at position 49 of exon 1 was analyzed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. The patients were also analyzed with respect to HLA-DR status. HLA-DR typing was performed by PCR sequence-specific oligonucleotide typing. RESULTS: The distribution of genotype frequencies differed between RA and controls (chi-squared 8.63, 2 df, p = 0.013). The CTLA-4 AG genotype occurred more frequently in patients with RA (59 vs 44%), and the presence of at least one G allele (GG or AG) conferred an odds ratio of 2.53 (95% CI 1.74-3.32). When the patients were analyzed with respect to HLA-DR status, this association was restricted to patients carrying the susceptible HLA allele (HLA-DRB1*0405). CONCLUSION: The CTLA-4 gene is associated with Japanese patients with RA carrying the susceptible HLA allele.

Abatacept↗
PubMed1999

An evaluation of malignancy and prognostic factors based on mode of lymph node metastasis in esophageal carcinoma.

This study was conducted to evaluate lymph node metastasis as a key prognostic factor in esophageal cancer. Metastatic lesions in lymph nodes were grouped by histological morphology as intracapsular or extracapsular, and the significance of lymph node metastasis was evaluated by relating metastatic lesions to clinical pathologic factors and patient prognosis. In our hospital, 46 of 81 patients who underwent resection of esophageal cancer developed lymph node metastasis. These 46 patients were enrolled in a study analyzing the relationship between the metastatic mode and the clinicopathological factors. The frequency of extracapsular metastasis was significantly high in patients with a profound depth of cancer, three or more metastases, distant metastasis (n3 and n4), or severe lymphatic invasion. The prognosis was significantly worse in patients with extracapsular metastasis, and this tendency was also seen even in patients with three or more metastases, limited metastasis (n1 and n2), or mild lymphatic invasion (ly0 and ly1). These findings suggest that the metastatic mode reflects the degree of esophageal cancer progression and is an important prognostic factor.

Aged↗
PubMed1999

Evaluation of malignancy and the prognosis of esophageal cancer based on an immunohistochemical study (p53, E-cadherin, epidermal growth factor receptor).

The subjects in this study consisted of 40 preoperative untreated esophageal squamous cell carcinoma patients. While p53 did not significantly correlate with the clinicopathological factors, E-cadherin significantly correlated with lymphatic invasion, vascular invasion, the depth of invasion, the degree of lymph node metastasis, the histological stage, and the number of lymph node metastases. Epidermal growth factor receptor (EGFR) significantly correlated with age, the depth of invasion, and the number of lymph node metastases. The 5-year cumulative survival rate was 45.7% in the p53-positive cases and 61.9% in the p53-negative cases, with no significant difference, and 87.8% in the E-cadherin-positive cases and 19.1% in the -negative cases, and the difference was significant. The prognosis was significantly poor in EGFR-positive subjects: the 5-year survival rate was 38.6% in EGFR-positive cases and 68% in -negative cases. The 5-year survival rate in E-cadherin-negative, EGFR-positive cases was 0%, while it was 91.7% in the reverse pattern, and this difference was significant. These findings suggest that both E-cadherin and EGFR are important prognostic factors, and a more precise prognosis can thus be obtained by combining them. Such a combined technique may be very useful as an indicator for grading the biological malignancy of esophageal cancer.

Adult↗
PubMed1999

Influence of genotypes at SAA1 and SAA2 loci on the development and the length of latent period of secondary AA-amyloidosis in patients with rheumatoid arthritis.

To examine whether polymorphism at the SAA loci is associated with the development of amyloid protein A (AA)-amyloidosis, we determined the genotypes at the SAA1 and SAA2 loci in 43 AA-amyloidosis patients (amyloidosis population) and 77 patients with rheumatoid arthritis (RA) who had been ill for less than 5 years (early RA population). We also compared the frequencies of the genotypes at the SAA1 locus among 90 Korean, 95 Taiwanese, and 103 Japanese healthy subjects. The frequencies of the gamma/gamma genotype and gamma alleles at the SAA1 locus were significantly higher in the amyloidosis population than in the early RA population (34.9% versus 7.8%, and 58.1% versus 33.8%, chi2 test P=0.0001). The frequencies of the gamma allele at the SAA1 locus in Koreans, Taiwanese, and Japanese were 41.6%, 35.6%, and 37.4%, respectively. The length of the latent period of AA-amyloidosis was significantly longer in the patients with smaller numbers of the gamma allele at the SAA1 locus (Spearman's correlation coefficient: -0.42, P<0.05). On the other hand, the mean C-reactive protein (CRP) level during 2 years prior to the diagnosis of AA-amyloidosis was significantly higher in the patients with larger numbers of the gamma allele at the SAA1 locus (Spearman's correlation coefficient: 0.34, P<0.05). No significant association was found between amyloidosis and polymorphism at the SAA2 locus. We postulate that the allele SAA1gamma renders an RA patient susceptible to amyloidosis, possibly by affecting the severity of inflammation in RA.

Adult↗