Biomedical subjects

T Kawano

Publications and source records attributed to T Kawano.

At least 109 records · Page 6Linked to original sources

PubMed2000

Hexamethylene diisocyanate causes contraction of canine tracheal smooth muscles through activation of muscarinic receptors.

BACKGROUND: Asthma caused by occupational exposure to hexamethylene diisocyanate (HDI) is well known; however, the exact pathogenic mechanisms remain unclear. METHODS: Experiments were performed using a standard canine tracheal smooth muscle (CTSM) strip preparation in an isolated bath to determine the effect of HDI on tracheal smooth muscle contraction. HDI concentration-response curves were constructed and the effects of different receptor antagonists on HDI-induced smooth muscle contraction were determined. To determine whether HDI and acetylcholine (ACh) bind to a common muscarinic receptor, ACh concentration-response curves in the absence or presence of HDI and concentration-response curves for HDI and ACh in the presence or absence of atropine were plotted. RESULTS: HDI caused contraction of CTSM, with a threshold concentration of 10(-7) M. The EC(50) (HDI concentration that produced 50% of the maximal response) was 6.2+/-0.7 x10(-7) M and the maximal contractile response (174+/-55 g/g of tissue) occurred at a concentration of 5.0+/-0.8 x 10(-6) M. Atropine, a muscarinic blocker, significantly inhibited HDI-induced contractile responses. HDI shifted the ACh concentration-response curve to the right. The mean pA(2) for atropine against ACh (8.93+/-0.27) was not significantly different from that against HDI (8.03+/-0.12). CONCLUSIONS: Our results indicated that HDI causes contraction of CTSM through the activation of muscarinic receptors. Direct stimulation of muscarinic receptors by HDI may play an important role in HDI-induced asthma.

Acetylcholine↗

PubMed2000

CD13/aminopeptidase N, a novel chemoattractant for T lymphocytes in pulmonary sarcoidosis.

CD13/aminopeptidase N (E.C.3.4.11.2) is an ectoenzyme located in the outer membrane of a variety of cells. Because aminopeptidase expression was shown to be upregulated by a Th1-related cytokine, IFN-gamma, we examined here the significance of CD13/aminopeptidase N in pulmonary sarcoidosis. The activity of aminopeptidase in bronchoalveolar lavage fluid (BALF) was significantly higher in patients with sarcoidosis than in normal volunteers (NV) and control patients (CP). The activity significantly correlated with lymphocyte percentages and the ratio of CD4+ to CD8+ T lymphocytes in the BALF, and was higher in patients with sarcoidosis with parenchymal involvement than in those without the involvement. CD13/aminopeptidase N protein, which has a molecular mass of approximately 150 kD, was detectable in alveolar macrophages (AM) from patients with sarcoidosis at higher levels than in those from NV. CD13/aminopeptidase N induced in vitro chemotactic migration of human lymphocytes in a concentration range of 10(-)(5) to 10(-)(1) U/ml. The chemotactic activity was greater for CD4+ T lymphocytes than for CD8+ T lymphocytes. The enzymatic activity of CD13/aminopeptidase N was responsible for the chemotactic activity because bestatin, an inhibitor of CD13/aminopeptidase N, abolished the chemotactic activity. Higher chemotactic activity for lymphocytes was detected in the BALF from patients with sarcoidosis than in that from NV, and the activity was significantly decreased by treatment with bestatin. This study indicates that CD13/ aminopeptidase N expressed in AM may have a role in T-lymphocyte involvement in the sarcoid lung and the pathogenesis of alveolitis in this disorder.

Adult↗

PubMed2000

Phytotoxicity of indole-3-acetic acid produced by the fungus, Pythium aphanidermatum.

Pythium aphanidermatum causes the serious disease of Pythium red blight on bentgrass. IAA, one of the metabolites that has been isolated from this fungus, showed the same symptom of Pythium red blight on bentgrass at a concentration of 1,000 mg/1. The IAA content in the foliage of bentgrass infected by this fungus was about 200 times that of an untreated control. These results suggest that IAA produced by this fungus was the causal substance of Pythium red blight on bentgrass.

Indoleacetic Acids↗

PubMed2000

Nematicidal alkaloids and related compounds produced by the fungus Penicillium cf. simplicissimum.

A new nematicidal alkaloid, peniprequinolone (1), together with the known alkaloids penigequinolones A and B (2a, 2b), 3-methoxy-4-hydroxy-4-(4'-methoxyphenyl)quinolinone (3), and 3-methoxy-4,6-dihydroxy-4-(4'-methoxyphenyl)quinolinone (4), were isolated from Penicillium cf. simplicissimum (Oudemans) Thom. Cyclopenin (5) and a compound (6a/6b) structurally related to cyclopenin also were isolated from the fungus, and their structures were established by spectroscopic analysis. The biological activities of 1, 2, 3, 4, and 5 were examined by a bioassay with root-lesion nematodes.

Alkaloids↗

PubMed2000

Pseudoaneurysm of the superficial temporal artery following craniotomy--case report.

A 48-year-old male without marked blood coagulation disorder developed a pseudoaneurysm of the superficial temporal artery (STA) following craniotomy. Cerebral angiography revealed a pseudoaneurysm on the parietal branch of the STA. Total extirpation was performed, and the postoperative course was uneventful. Most pseudoaneurysms of the STA develop after trauma. Lesions rarely develop after craniotomy. However, pseudoaneurysm of the STA should be considered as a possible surgical complication.

Aneurysm, False↗

PubMed2000

Transarterial embolization with HEMA-MMA of variant convexity-superior sagittal sinus dural arteriovenous fistula--case report.

A 62-year-old male presented with a variant dural arteriovenous fistula (DAVF) within the wall of the convexity-superior sagittal sinus, fed by branches of the bilateral external carotid arteries and only cortical venous drainage despite the presence of a patent sinus. Transarterial embolization with poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (HEMA-MMA) was performed, resulting in complete obliteration of the DAVF. Embolization with HEMA-MMA is an effective and safe procedure for the treatment of DAVF.

Biocompatible Materials↗

PubMed2000

Dissecting aneurysm of the vertebral artery causing subarachnoid hemorrhage after non-hemorrhagic infarction--case report.

A 45-year-old male presented with lateral medullary infarction. Cerebral angiography showed dissecting aneurysm as pearl and string sign in the right vertebral artery (VA). Conservative treatment was administered with antiplatelet agent. However, subarachnoid hemorrhage occurred 2 days after admission, inducing coma. Intraaneurysmal embolization and proximal occlusion of the right VA by intravascular surgery resulted in only mild neurological deficits. Conservative treatment including strict control of blood pressure is the first choice of treatment. Antiplatelet therapy and anticoagulant therapy should not be administered. Patients must be followed up by serial angiography and surgery considered if signs of aneurysmal progression are seen.

Aortic Dissection↗

PubMed2000

[Antitumor effect of the angiogenesis inhibitor, TNP470, on squamous cell carcinoma cells in head and neck cancer].

The antitumor effect of the angiogenesis inhibitor TNP470, O-(chloro-acetyl-carbamoyl) fumagillol, a synthetic analogue of fumagillin, was studied in vitro and in vivo on, cell line KB which produced interleukin (IL)-8. In vitro, TNP470 reduced the production of IL-8 from KB cells, the same as anti-IL-8 antibody (Ab.) The combination of anti-IL-8 Ab (10 micrograms/ml) and TNP470 (10 ng/ml) significantly inhibited the proliferation of KB cells, compared to no treatment (p < 0.05). Proliferation of KB cells was also significantly more suppressed by simultaneous treatment of cisplatin and TNP470 (1 mg/ml), than cisplatin alone. The in vivo antitumor effect of TNP470 was studied using anti-IL-8 Ab, anti-vascular endothel growth factor (VEGF) Ab, and TNP470, in administered by different routes, i.e., intratumoral (i.t.), intraperitoneal (i.p.), and intravenous. TNP470 (10 mg/ml) showed an antitumor effect, and intratumoral administration of TNP470 was the most effective route. Combined administration of anti-IL-8 Ab (i.p.) and TNP470 (i.t.) reduced tumor volume more than anti-IL-8 Ab alone did. These results suggest that the combination of TNP470, cisplatin, and anti-IL-8 Ab could be a beneficial treatment for solid tumors of the head and neck.

Angiogenesis Inhibitors↗

PubMed2000

Three-dimensional helical computed tomographic angiography in neonates and infants with complex congenital heart disease.

BACKGROUND: For the clinical management of patients with complex congenital heart disease (CHD), accurate evaluation of their morphologic conditions is critical. Three-dimensional (3D) helical computed tomography (CT) angiography has been used to assess the vascular system in adult patients; the indication for complex CHD, especially in the neonatal period, has not yet been defined. Therefore the purposes of our study were to determine the quality and limitations of current 3D helical CT angiography for neonates and infants with complex CHD and to assess the clinical utility of this technique. METHODS AND RESULTS: 3D helical CT angiography was performed in 17 patients with various types of complex CHD. Their median age was 41 days (range 3 days to 9 months), and mean body weight was 3.6 kg (range 2.2 to 8.5 kg). All 3D images were produced with the 3D reconstruction algorithm of shaded-surface display. Oral sedation was required in only 4 infants during the procedure. 3D helical CT angiography clearly demonstrated the shape and spatial relation of great arteries, proximal branch pulmonary arteries, anomalous pulmonary venous connections, the patent ductus arteriosus, and a shunt. The 3D information of extracardiac morphologic characteristics and 3D anatomic relation of each extracardiac structure were easily recognized by this imaging process. However, intracardiac structure could not be visualized because of blurred and/or unclear edges of the ventricular wall caused by respiratory movement. CONCLUSIONS: 3D helical CT angiography represents an important additional diagnostic tool and may become an alternative method to angiography or other noninvasive techniques used in the evaluation of extracardiac anomalies in neonates and infants with complex CHD.

Adult↗

PubMed2000

[Early experience with the freestyle stentless xenograft].

We performed aortic valve replacement with the Freestyle stentless xenograft in 9 patients. There were 6 men and 2 women, whose ages ranged from 44 to 76 years. The modified subcoronary implantation was used in 6 patients and the completely subcoronary implantation was used in 2 patients. The full root replacement was used in 1 patient with bicuspid aortic valve. In a patient who underwent root replacement, postoperative cineangiogram revealed just proximal right coronary artery stenosis. The patient underwent coronary artery bypass grafting to right coronary artery by use of the right internal mammary artery. One in-hospital death occurred on the 46th postoperative day in a patient with severe aortic stenosis and renal failure. 5 patients were investigated by doppler echocardiography at 2 weeks, 3, 6, and 12 months after operation. Peak pressure gradient 1 year after implantation was 11.7 +/- 3.9 mmHg for all valves. No patient had postoperative significant aortic regurgitation.

Adult↗

PubMed2000

[A comparison of bullard laryngoscope and intubating laryngeal mask using fiberoptic guidance for tracheal intubation].

The purpose of this study is to compare the success rate of tracheal intubation, intubation time and laryngoscopic view of the larynx by Bullard laryngoscope or by intubating laryngeal mask using fiberoptic guidance in 50 patients. Following a standardized induction protocol, conventional laryngoscopic view by Macintosh's laryngoscope was obtained and classified by Cormack's grades. We measured the times from incertion of laryngoscopy or laryngeal mask until obtaining the best view of the larynx and until tracheal intubation. A best view by Bullard laryngoscopy or by fiberoscopy through the laryngeal mask was classified by Cormack's grades. The success rate of tracheal intubation was higher by Bullard laryngoscopy than by intubating laryngeal mask. The durations of laryngoscopy and tracheal intubation were significantly shorter and Cormack's grades were significantly lower by Bullard laryngoscopy than by laryngeal mask and fiberscopy. These results demonstrate that tracheal intubation by Bullard laryngoscope is faster and more successful compared with intubating laryngeal mask using fiberoptic guidance.

Adolescent↗

PubMed2000

Mechanism of peroxidase actions for salicylic acid-induced generation of active oxygen species and an increase in cytosolic calcium in tobacco cell suspension culture.

Extracellularly secreted peroxidases in cell suspension culture of tobacco (Nicotiana tabacum L. cv. Bright Yellow-2, cell line BY-2) catalyse the salicylic acid (SA)-dependent formation of active oxygen species (AOS) which, in turn, triggers an increase in cytosolic Ca2+ concentration. Addition of horseradish peroxidase (HRP) to tobacco cell suspension culture enhanced the SA-induced increase in cytosolic Ca2+ concentration, suggesting that HRP enhanced the production of AOS. The mechanism of peroxidase-catalysed generation of AOS in SA signalling was investigated with chemiluminescence sensitive to AOS and electron spin resonance (ESR) spectroscopy, using the cell suspension culture of tobacco, and HRP as a model system of peroxidase reaction. The results showed that SA induced the peroxidase inhibitor-sensitive production of superoxide and H2O2 in tobacco suspension culture, but no production of hydroxy radicals was detected. Similar results were obtained using HRP. It was also observed that SA suppressed the H2O2-dependent formation of hydroxy radicals in vitro. The results suggest that SA protect the cells from highly reactive hydroxy radicals, while producing the less reactive superoxide and H2O2 through peroxidase-catalysed reaction, as the intermediate signals. The formation of superoxide was followed by that of H2O2, suggesting that superoxide was converted to H2O2. In addition, it was observed that superoxide dismutase-insensitive ESR signal of monodehydroascorbate radical was induced by SA both in the tobacco suspension culture and HRP reaction mixture, suggesting that SA free radicals, highly reactive against ascorbate, were formed by peroxidase-catalysed reactions. The formation of SA free radicals may lead to subsequent monovalent reduction of O2 to superoxide.

Calcium↗

PubMed2000

[Barrett's esophagus].

The Barrett's esophagus showing columnar metaplasia upward to the esophagus from the esophago-gastric junction is one of the final appearance of reflux esophagitis and important as a precancerous state of esophageal adenocarcinoma. Especially the Barrett's mucosa with intestinal metaplasia has high potential risk for adenocarcinoma. Although the clinical definition of the esophago-gastric junction is not easy, the criteria of the esophago-gastric junction and the Barrett's mucosa proposed by the Japanese Society for Esophageal Diseases is useful. The gastro-esophageal reflux is important in the development of Barrett's mucosa not only in the classical Barrett's esophagus but also in the short-segment Barrett's.

Barrett Esophagus↗

PubMed2000

[Hepatic arterial infusion chemotherapy for liver metastasis from esophageal squamous cell carcinoma].

Since 1993, we have treated 9 patients with liver metastases from esophageal squamous cell carcinoma using hepatic arterial infusion chemotherapy (HAI). These patients underwent esophagectomy and reconstruction with a stomach roll, and without preoperative chemotherapy and/or radiotherapy, HAI was effective in 5 patients (56%) with a CR in 2 patients. Preceding systemic chemotherapy was done with 7 patients, and was effective in 3 of them. HAI was also effective in all of them. In 3 patients with hepatic arterial anomalies, the right gastroepiploic artery and right gastric artery feeding the stomach roll could be preserved after changing the hepatic arterial flow. Two stomach roll ulcers and one hepatic arterial stenosis were experienced due to the toxicity of HAI. However, the nausea, vomiting, diarrhea, and/or myelosuppression seen with the preceding systemic chemotherapy were not experienced. In spite of the technical difficulties in catheterization and toxicities to stomach roll, HAI is considered to be more effective and feasible than systemic chemotherapy.

Aged↗

PubMed2000

[rCBF study with 123I-IMP SPECT of dural arteriovenous fistula].

It is important for dural arteriovenous fistula (DAVF) to evaluate venous ischemia in the brain related to venous hypertension, but only a few such studies have been performed. In this study, regional cerebral blood flow(rCBF) in DAVF was examined for venous ischemia by 123I-IMP SPECT. The subjects were eighteen patients with DAVF. Of the eighteen patients, nine had DAVF with low perfusion areas and venous ischemia. The factors affecting rCBF in DAVF are: 1) the presence of retrograde leptomeningeal venous drainage, 2) sinus occlusion, and 3) DAVF with high flow. The presence of retrograde leptomeningeal venous drainage was observed in nine patients, sinus occlusion in four patients, high flow in three patients. In two patients, pure leptomeningeal venous drainage was formed by patent sinus, and blood regurgitated from DAVF on the sinus wall to cortical vein. When DAVF was associated with LMVD, most patients had venous hypertension and concomitant venous congestion in the same areas due to reduced venous circulation, resulting in a decrease in rCBF and an increase in regional cerebral blood volume. These hemodynamics suggest venous ischemia in the brain. 123I-IMP SPECT was useful for evaluating rCBF and as a parameter of the treatment.

Adult↗

PubMed1999

Importance of the G protein gamma subunit in activating G protein-coupled inward rectifier K(+) channels.

The G protein-coupled inward rectifier K(+) channel (GIRK) is activated by direct interaction with the heterotrimeric GTP-binding protein betagamma subunits (Gbetagamma). However, the precise role of Gbeta and Ggamma in GIRK activation remains to be elucidated. Using transient expression of GIRK1, GIRK2, Gbeta1, and Ggamma2 in human embryonic kidney 293 cells, we show that C-terminal mutants of Gbeta1, which do not bind to Ggamma2, are still able to associate with GIRK, but these mutants are unable to induce activation of GIRK channels. In contrast, other C-terminal mutants of Gbeta1 that bind to Ggamma2, are capable of activating the GIRK channel. These results suggest that Ggamma plays a more important role than that of an anchoring device for the Gbetagamma-induced GIRK activation.

Cell Line↗

PubMed1999

Antitumor cytotoxicity mediated by ligand-activated human V alpha24 NKT cells.

Human V alpha24 NKT cells bearing an invariant V alpha24J alphaQ antigen receptor, the counterpart of the murine V alpha14 NKT cells, are activated by the specific ligand, alpha-galactosylceramide (alpha-GalCer) in a CD1d-dependent manner. Here, we demonstrate that the alpha-GalCer-activated V alpha24 NKT cells exert a potent perforin-dependent cytotoxic activity against a wide variety of human tumor cell lines. In addition, we demonstrate that V alpha24 NKT cells and dendritic cells (DCs) from melanoma patients are functionally normal, even in the tumor-bearing status. The potential use of alpha-GalCer-activated V alpha24 NKT cells and/or DCs from patients for cancer immunotherapy is discussed.

Adult↗

PubMed1999

Inhibition of T helper cell type 2 cell differentiation and immunoglobulin E response by ligand-activated Valpha14 natural killer T cells.

Murine Valpha14 natural killer T (NKT) cells are thought to play a crucial role in various immune responses, including infectious, allergic, and autoimmune diseases. Because Valpha14 NKT cells produce large amounts of both interleukin (IL)-4 and interferon (IFN)-gamma upon in vivo stimulation with a specific ligand, alpha-galactosylceramide (alpha-GalCer), or after treatment with anti-CD3 antibody, a regulatory role on helper T (Th) cell differentiation has been proposed for these cells. However, the identity of the cytokine produced by Valpha14 NKT cells that play a dominant role on the Th cell differentiation still remains controversial. Here, we demonstrate by using Valpha14 NKT-deficient mice that Valpha14 NKT cells are dispensable for the induction of antigen-specific immunoglobulin (Ig)E responses induced by ovalbumin immunization or Nippostrongylus brasiliensis infection. However, upon in vivo activation with alpha-GalCer, Valpha14 NKT cells are found to suppress antigen-specific IgE production. The suppression appeared to be IgE specific, and was not detected in either Valpha14 NKT- or IFN-gamma-deficient mice. Consistent with these results, we also found that ligand-activated Valpha14 NKT cells inhibited Th2 cell differentiation in an in vitro induction culture system. Thus, it is likely that activated Valpha14 NKT cells exert a potent inhibitory effect on Th2 cell differentiation and subsequent IgE production by producing a large amount of IFN-gamma. In marked contrast, our studies have revealed that IL-4 produced by Valpha14 NKT cells has only a minor effect on Th2 cell differentiation.

Animals↗