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Biomedical subjects

N Kobayashi

Publications and source records attributed to N Kobayashi.

At least 145 records · Page 8Linked to original sources
PubMed2001

Effects of TCV-116 on endothelin-1 and PDGF A-chain expression in angiotensin II-induced hypertensive rats.

Angiotensin II (Ang II) has been shown to stimulate cardiac growth and collagen synthesis in cultured vascular smooth muscle cells and to increase fibroblast proliferation. Chronic infusion with Ang II increases blood pressure and activates growth mechanisms to produce hypertrophy of the heart. This study investigated the effects of an Ang II type 1 receptor antagonist, TCV-116, on preproendothelin-1 (preproET-1), ETA receptor and platelet-derived growth factor (PDGF) A-chain expression in the left ventricle of Wistar-Kyoto rats treated for 2 weeks with Ang II (200 ng x kg(-1) x min(-1)), and the relation of these effects to myocardial remodeling. Rats given Ang II alone (ANGII-V) were compared with rats also receiving TCV-116 (ANGII-TCV). In both groups, blood pressure was similar and significantly higher than in control rats. The preproET-1, ET(A) receptor and PDGF A-chain expressions in the left ventricle were significantly increased in ANGII-V compared with control rats, and were significantly suppressed in ANGII-TCV compared with ANGII-V rats. ANGII-V rats showed a significant increase of the type I collagen expression, wall-to-lumen ratio, perivascular fibrosis, and myocardial fibrosis, with all these parameters being significantly improved by TCV-116. Myocardial remodeling in Ang II-induced hypertensive rats was significantly ameliorated by a subdepressor dose of TCV-116, which may have been due to a decrease in ET-1 and PDGF A-chain expression in the left ventricle.

Angiotensin II↗
PubMed2001

Spectroscopic probing of the acid-base properties and photosensitization of a fluorinated phthalocyanine in organic solutions and liposomes.

A perfluorinated derivative of phthalocyanine was synthesized as the free base, hexadeca-(2,2,2-trifluoroethoxy) phthalocyanine (H2F48Pc), and as a zinc complex, hexadeca-(2,2,2-trifluoroethoxy)-phthalocyaninatozinc (ZnF48Pc), and their spectroscopic and photochemical properties were studied. The absorption bands are shifted bathochromically relative to simple phthalocyanines, exhibiting the longest wavelength band near 735 nm (H2F48Pc) and 705 (ZnF48Pc). The solvatochromism of both compounds was modeled by Reichardt's ET(30) parameter and Kamlet, Abboud and Taft multiparameter approach. The former, simpler, model was found to be adequate. We found that H2F48Pc undergoes unique basic and acidic titrations in organic solvents. These titration processes are accompanied by spectral changes that are explained on the basis of the chromophore's symmetry. Singular value decomposition was employed to resolve the spectra into the contributions of the species at various stages of protonation and to obtain the equilibrium constants. Nuclear magnetic resonance spectra (1H, 19F and 13C) for the free base were obtained in a tetrahydrofurand8 solution. The carbon spectrum, taken as a function of temperature, provided evidence for the presence of a tautomerization process, which switches the two internal hydrogens between the four central nitrogen atoms. As far as we know, this is the first report of the measurement of the free energy of activation for such process (delta G = 10.6-11.4 kcal mol-1 between 217 and 330 K) for a phthalocyanine, in solution. Like most other phthalocyanines these two compounds also act as photosensitizers and as generators of singlet molecular oxygen. The absolute quantum yields (phi delta) for ZnF48Pc was 0.58 +/- 0.01 in benzene and 0.35 +/- 0.01 in lipid vesicles. H2F48Pc had lower yields, 0.16 and 0.005, respectively. Either protonation or deprotonation of the pyrrole nitrogens in H2F48Pc lowered the phi delta.

Hydrogen-Ion Concentration↗
PubMed2001

Effect of a platelet-activating factor receptor antagonist, E5880, on cerebral vasospasm after aneurysmal subarachnoid hemorrhage--open clinical trial to investigate efficacy and safety.

The efficacy and safety of a new platelet-activating factor receptor antagonist, E5880, were investigated for preventing cerebral vasospasm after subarachnoid hemorrhage (SAH) in 71 patients with SAH who underwent surgery for ruptured aneurysms within 3 days. Intravenous E5880 administration (300 micrograms or 1200 micrograms twice daily) was begun within 4 days and continued for 14 days. The incidence of symptomatic vasospasm, low-density area on computed tomography, and angiographic vasospasm was lower than in placebo groups in previous studies. Clinical outcome was favorable compared with previous studies. No clinically important adverse events were observed. These results suggest that E5880 is safe and effective in the treatment of patients with cerebral vasospasm due to SAH.

Adult↗
PubMed2001

[Usefulness of right ventricular Doppler index for predicting outcome in patients with dilated cardiomyopathy].

OBJECTIVES: Left ventricular Doppler index (LVDI) is believed to be a useful echocardiographic index of systolic and diastolic ventricular function. However, the usefulness of right ventricular Doppler index (RVDI) remains uncertain, especially in dilated cardiomyopathy. The predictive value of RVDI for estimating long-term cardiac events, including cardiac death, was investigated. METHODS: Fifty-nine consecutive patients with dilated cardiomyopathy (41 males and 18 females, mean age 52 +/- 15 years) were enrolled in this follow-up study. RVDI and LVDI were calculated as follows: DI = (isovolumic contraction time + isovolumic relaxation time)/ejection time. RESULTS: During a follow-up period of 3.7 +/- 3.0 years, 27 (46%) of the patients exhibited cardiac events, including cardiac death (n = 9), heart failure (n = 16) and tachyarrhythmias (n = 2) requiring in-hospital treatment. Patients with these cardiac events had higher LVDI and RVDI at the initial follow-up examination, and RVDI had a significant linear correlation with LVDI (LVDI = 0.550 + 0.452 x RVDI, r = 0.530, p = 0.0001). The 6-year survival rate was significantly lower in patients with both LVDI > or = 0.78 and RVDI > or = 0.49 than in other patients (50% vs 75%, respectively, p = 0.009). Cox proportional hazards model analysis showed that RVDI > or = 0.49 was the independent predictor of cardiac events (p = 0.0153) and cardiac death (p = 0.0003). CONCLUSIONS: RVDI is clinically useful for estimating the outcome of patients with dilated cardiomyopathy.

Adult↗
PubMed2001

[A case of recurrent gastric cancer successfully treated with TS-1].

A patient with recurrent gastric cancer which infiltrated the pelvic muscle after the treatment of paraaortic lymph node and ovarian metastases was successfully managed by a novel oral anticancer drug, TS-1. TS-1 was administered at a dose of 80 mg/day. One course consisted of two repetitions of consecutive administration of TS-1 for 14 days and withdrawal of TS-1 for 14 days. Adverse reactions were mild and the patient did not request hospitalization after two courses had been completed. Subjective symptoms such as difficulty in walking improved after one week and a partial response was obtained after 2 weeks of treatment. At the end of 4 courses we could remove an indwelling pyelocatheter for the ureter stricture. As of 14 months after the beginning of administration of TS-1, the patient is being treated as an outpatient and has attained a better QOL than before.

Aged↗
PubMed2001

Hepatic uptake and gene expression mechanisms following intravenous administration of plasmid DNA by conventional and hydrodynamics-based procedures.

Hepatic uptake and gene expression mechanisms following intravenous administration of naked plasmid DNA (pDNA) by conventional and hydrodynamics-based procedures were studied in mice. After conventional (normal) intravenous injection, (32)P-labeled pDNA was rapidly eliminated from the circulation and predominantly taken up by the liver nonparenchymal cells while no significant gene expression was observed in this organ. The hepatic uptake process was saturable. Involvement of a specific mechanism was demonstrated since the hepatic uptake of [(32)P]pDNA was dramatically inhibited by cold pDNA, calf thymus DNA, and some polyanions [polyinosinic acid (poly I), dextran sulfate], but not by others (polycytidylic acid, chondroitin sulfate). The liver endothelial cells appeared to be a major contributor because gadolinium chloride (GdCl(3))-induced Kupffer cell blockade did not affect the hepatic uptake. After intravenous injection of naked pDNA with a large volume of saline at a high velocity (hydrodynamics-based procedure), the apparent hepatic uptake profile was similar to that after normal injection. The hepatic uptake was not inhibited by prior administration of polyanions, including poly I, dextran sulfate, and heparin. The hydrodynamics-based procedure resulted in marked gene expression in the liver, which was not inhibited by prior administration of polyanions or GdCl(3) treatment. These results indicate that pDNA uptake is a nonspecific process. This hypothesis was supported by the finding that significant hepatic uptake of bovine serum albumin and immunoglobulin G was observed after the hydrodynamics-based procedure.

Animals↗
PubMed2001

Role of p38 mitogen-activated protein kinase in the healing of gastric ulcers in rats.

p38 belongs to the mitogen-activated protein kinase family and plays a crucial role in cellular responses to both cytokines and various stresses. We investigated the role of p38 in the healing of experimental gastric ulcers. Gastric ulcers were induced by submucosal injection of acetic acid solution into male rats. Western blotting and a kinase assay examined the p38 activity and phosphorylation state in ulcerated tisue. After orally administering FR167653 (p38 kinase inhibitor) for 3 to 14 days, the production level of cytokines and the protein-level expression of cyclooxygenase and inducible nitric oxide synthase were examined by enzyme-linked immunosorbent assay and Western blotting. Only in fibroblasts and macrophages/monocytes in ulcerated tissue, p38 was found to be phosphorylated with an elevated kinase activity level. FR 167653 inhibited the activity of p38, yet had no effect on its phosphorylation state. The drug significantly impaired ulcer healing (without affecting acid secretion) and angiogenesis in the ulcer base. The production of interleukin-1beta and tumor necrosis factor-alpha were significantly reduced after FR167653 treatment. In addition the expression of cyclooxygenase-2 and inducible nitric oxide synthase proteins increased PGE2 generation and NOx secretion in the ulcerated stomach were suppressed by FR167653. From these findings, we conclude that p38, activated by gastric ulceration, might play some role in the healing of gastic ulcers in rats.

Animals↗
PubMed2001

Prevention of neutrophil-mediated hepatic ischemia/reperfusion injury by superoxide dismutase and catalase derivatives.

Our previous study demonstrated that the combination of mannosylated superoxide dismutase (Man-SOD) and succinylated catalase (Suc-CAT), both of which are designed to be targeted to liver nonparenchymal cells, is a promising approach to prevent the initial phase of hepatic ischemia/reperfusion injury induced by occlusion of the portal vein for 30 min followed by a 1-h reperfusion in mice. In this study, the preventive effects of these agents were examined on late-phase injury mediated by infiltrating neutrophils, a more severe condition than the initial one. Administration of Suc-CAT alone or with Man-SOD to mice undergoing hepatic ischemia/reperfusion significantly suppressed the expression of intercellular adhesion molecule-1 along the hepatic sinusoid and prevented neutrophil infiltration in the liver. Man-SOD and Suc-CAT also prevented the increase in plasma glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activities after reperfusion lasting 3 and 6 h. Histological evaluation of liver tissues confirmed the efficacy of this treatment, suggesting that these SOD and catalase derivatives have the ability to suppress neutrophil-induced hepatic injury. These results demonstrate that targeted delivery of antioxidant enzymes to liver nonparenchymal cells is a promising approach to reducing the reactive oxygen species produced by Kupffer cells and neutrophils infiltrating into the tissue. Since Suc-CAT is partially taken up by hepatocytes via a catalase-specific uptake mechanism, such a fraction could also be involved in its preventive effect against the injury.

Alanine Transaminase↗
PubMed2001

Insertion of a suicide gene into an immortalized human hepatocyte cell line.

For developing a bioartificial liver (BAL) device, an attractive alternative to the primary human hepatocytes would be the use of highly differentiated immortalized human hepatocytes with a safeguard. To test the feasibility, the primary human hepatocytes were immortalized by a plasmid SV3neo encoding simian virus 40 large T antigen (SV40Tag) gene. A highly differentiated hepatocyte line OUMS-29 was established. A suicide gene of herpes simplex virus-thymidine kinase (HSV-TK) was retrovirally introduced into OUMS-29 cells as a safeguard for clinical application. One of the resulting HSV-TK-positive cell lines, OUMS-29/tk, grew in chemically defined serum-free medium with the gene expression of differentiated liver functions. OUMS-29/tk cells were 100 times more sensitive to ganciclovir compared with unmodified OUMS-29 cells in in vitro experiments. We have established a tightly regulated immortalized human hepatocyte cell line. Essentially unlimited availability of OUMS-29/tk cells may be clinically useful for BAL therapy.

Antiviral Agents↗
PubMed2001

Successful retroviral gene transfer of simian virus 40 T antigen and herpes simplex virus-thymidine kinase into human hepatocytes.

Current clinical reports have indicated that hepatocyte transplantation (HTX) could be used in patients with liver failure and in children with liver-based metabolic diseases. One of the major limiting factors of HTX is a serious shortage of donor livers for hepatocyte isolation. To address this issue, we immortalized adult human hepatocytes with a retroviral vector SSR#69 expressing the genes of simian virus 40 large T antigen and herpes simplex virus-thymidine kinase simultaneously. One of the resulting clones, NKNT-3, grew steadily in chemically defined serum-free medium without any obvious crisis and showed the gene expression of differentiated liver functions. Under the administration of 5 microM ganciclovir, NKNT-3 cells stopped proliferation and died in in vitro experiments. We have established a tightly regulated immortal human hepatocyte cell line. The cells could allow the need for immediate availability of consistent and functionally uniform cells in sufficient quantity and adequate quality.

Antigens, Polyomavirus Transforming↗
PubMed2001

Cre/loxP-based reversible immortalization of human hepatocytes.

An ideal alternative to the primary human hepatocytes for hepatocyte transplantation would be to use a clonal cell line that grows economically in culture and exhibits the characteristics of differentiated, nontransformed hepatocytes following transplantation. The purpose of the present studies was to establish a reversibly immortalized human hepatocyte cell line. Human hepatocytes were immortalized with a retroviral vector SSR#69 expressing simian virus 40 large T antigen (SV40Tag) gene flanked by a pair of loxP recombination targets. One of the resulting clones, NKNT-3, showed morphological characteristics of liver parenchymal cells and expressed the genes of differentiated liver functions. NKNT-3 cells offered unlimited availability. After an adenoviral delivery of Cre recombinase and subsequent differential selection, efficient removal of SV40Tag from NKNT-3 cells was performed. Here we represent that elimination of the retrovirally transferred SV40Tag gene can be excised by adenovirus-mediated site-specific recombination.

Cell Line↗
PubMed2001

Rapidly functional immobilization of immortalized human hepatocytes using cell adhesive GRGDS peptide-carrying cellulose microspheres.

With the development of biotechnology, hepatic support by a hybrid artificial liver (HAL) using hepatocytes has been given much attention. Because the availability of human livers is limited, we have established a tightly regulated immortal human hepatocyte cell line, NKNT-3, for developing HAL. Because high-density cell culture allows the compactness of the HAL device and its easy use under emergency circumstances, we have developed cell adhesive GRGDS peptide-containing cellulose microspheres (GRGDS/CMS). The GRGDS/CMS efficiently immobilized NKNT-3 cells within 24 h in a stirred suspension culture. Electron microscopic examinations demonstrated glycogen granules and well-developed endoplasmic reticulum and mitochondria in NKNT-3 cells attached to the GRGDS/CMS. The cells showed ammonia clearance activity, whereas HepG2-transformed human liver cells did not remove the loaded ammonia. An efficient adenoviral delivery of the lacZ reporter gene was performed in GRGDS/CMS-immobilized NKNT-3 cells. In this study we present rapid immobilization of NKNT-3 immortal human hepatocytes using cellulose microspheres carrying GRGDS peptides. These microspheres satisfied immediate preparation of NKNT-3 cells in sufficient quantity and of adequate quality.

Ammonia↗
PubMed2001

[Case report of scimitar syndrome in infancy: intracardiac repair after coil embolization of systemic arterial supply to sequestered lung].

A 10-month-old girl was diagnosed with atrial septal defect and pulmonary sequestration and scimitar syndrome. Cardiac catheterization revealed severe pulmonary hypertension, with systemic pulmonary artery pressure 97 mmHg, pulmonary resistance 10.3 U, and Qp/Qs 0.45. Systemic pulmonary artery pressure was decreased from 108 to 75 mmHg by oxygenation. We performed coil embolization of the systemic artery and repair of the partial anomalous pulmonary venous return, division and reimplantation of the anomalous vein into the right atrium, and a patch was inserted to redirect flow to the left atrium. The severe pulmonary hypertension was improved and echocardiography showed systemic pulmonary artery pressure of 45 mmHg. The postoperative hemodynamic and respiratory condition was satisfactory.

Bronchopulmonary Sequestration↗
PubMed2001

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (1999)].

From October 1999 to September 2000, we collected the specimen from 430 patients with lower respiratory tract infections in 17 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and antibiotics and patients' characteristics. Of 515 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 506 strains were investigated. The breakdown of the isolated bacteria were: Staphylococcus aureus 78, Streptococcus pneumoniae 101, Haemophilus influenzae 104, Pseudomonas aeruginosa (non-mucoid) 58, P. aeruginosa (mucoid) 11, Moraxella subgenus Branhamella catarrhalis 41, Klebsiella pneumoniae 18, etc. Of 78 S. aureus strains, those with 4 micrograms/ml or above of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) occupied 57.7%. Vancomycin and arbekacin showed the most potent activities against MRSA without detection of ABK-resistant strain (MIC: 64 micrograms/ml) and decrease of VCM-sensitive strains those were found in 1998. The frequency of S. pneumoniae exhibiting low sensitivity to penicillin (penicillin-intermediate S. pneumoniae: PISP + penicillin-resistant S. pneumoniae: PRSP) decreased to 34.7% from 46.0% in 1998. The frequency of PRSP was 3.0%, being the least number after 1991. Carbapenems showed strong activities against S. pneumoniae. Especially, panipenem inhibited the growth of all 101 strains with MIC of 0.063 microgram/ml. Generally, all drugs showed strong activities against H. influenzae with MIC80s of 4 micrograms/ml or below. MICs of ofloxacin ranged between 0.063 microgram/ml and 4 micrograms/ml in 1998, however, those were 0.125 microgram/ml or below in all H. influenzae in 1999 showing the strongest activity. Tobramycin and ciprofloxacin showed strong activities against P. aeruginosa (both mucoid and non-mucoid) with MIC80s of 1 microgram/ml. Number of isolated P. aeruginosa (mucoid) was little as 11, however, the susceptibilities to all drugs were better than P. aeruginosa (non-mucoid). K. pneumoniae showed good susceptibilities to all drugs except for ampicillin with decreasing of low-sensitive strains compared to those detected in 1998. Also, all drugs generally showed strong activities against M. (B.) catarrhalis. MIC80s of all drugs were 2 micrograms/ml or below. The drug which showed the strongest activity was imipenem inhibiting all 41 strains with MIC of 0.063 microgram/ml. On the patients' characteristics, the number of patients aged 80 years or older who had been increased was decreased in 1999 in the distribution by age. The percentage of the elderly patients aged 70 years or older was 47.0%, which occupied almost a half number of the total patients as in the last year. As for the incidence by disease, bacterial pneumonia and chronic bronchitis were the highest. They were noted in 37.9% and 30.5% of the patients, respectively. In 1999, bronchial asthma was frequently observed as compared in recent years. It was noted in about 10% of the patients which is the same % as in bronchiectasis. We examined the number of strains from these patients with infections before and after administration of antibiotics. In patients with bacterial pneumonia, the number of isolated strains was almost the same between those before and after administration. However, in patients with chronic bronchitis, the number of strains remarkably decreased to less than the half of the total after administration of antibiotics in the last year, but it decreased to 2/3 of the total in 1999. On the administration of antibiotics and isolated bacteria by the day of administration, the bacteria which were isolated more before administration were H. influenzae in 28.4%, S. pneumoniae in 25.7%, M. (B.) catarrhalis in 12.0% and S. aureus in 10.6%. The frequency of S. aureus after administration over 15 days was almost the same as that before administration, but the frequency of P. aeruginosa (both mucoid and non-mucoid) was 36.8% which was higher than that before administration. The frequency of isolated S. pneumoniae was decreased after administration and none of them was isolated after completion of administration. However, that of H. influenzae was decreased to 7.1% after administration within 3 days, and many H. influenzae were isolated after completion of administration as 21.4%.

Adolescent↗
PubMed2001

[A case of thoracic vertebral tuberculosis associated with pulmonary sarcoidosis].

A 56-year-old woman was admitted to our hospital, on October 10, 1999 because of tingling numbness of the Th3 area and paraparesis. Her medical history included the diagnosis of pulmonary sarcoidosis which had responded to steroid therapy. On radiographic examination, a Th2 compression fracture and gadolinium enhanced areas were shown in MRI. We diagnosed vertebral sarcoidosis and restarted steroid therapy. Next day, she had no paresis and she was discharged after 20 days. However, the patient returned to our hospital with recurrence of the same pain and paraparesis on January 1, 2000, and spinal fusion of the Th2-3 was performed by a transpleural anterolateral approach using a block of iliac bone as a graft. Histology and cultural studies of tissue revealed tuberculosis. There is a diagnostic dilemma, "sarcoidosis or tuberculosis?", but it is necessary to be aware of this at the time of the initial diagnosis.

Female↗
PubMed2001

Morphogenetic activity of extracellular matrices on cultured podocytes. Laminin accelerates podocyte process formation in vitro.

Morphogenetic effects of various extracellular matrix proteins on the renal podocyte were investigated using the conditionally immortalized podocyte cell line. Podocytes were plated on glass coverslips and coated with the following matrix proteins: laminin-10/11, laminin-1, fibronectin, collagen type IV, collagen type I. Three hours after plating, podocytes on laminins developed prominent processes, while those on other matrix proteins started to elongate processes after two days. Vinculin-immunolabeling showed that podocytes plated on laminins possessed thin rod-shaped focal contacts, whereas those on fibronectin showed large dot-shaped focal contacts. Inhibition of serine/threonine protein kinases induced podocyte process formation in an extracellular matrix-independent manner. The present study reveals the significance of laminin on podocyte morphogenesis in vitro, and shows that different extracellular matrix proteins trigger different intracellular signals governing podocyte morphogenesis. Taken together with our previous studies, podocyte process formation is thought to be regulated by protein Ser/Thr phosphorylation.

Animals↗
PubMed2001

[Comparison of five guidelines of community-acquired pneumonia].

The aim of this retrospective study was to elucidate the characteristics of five guidelines of community-acquired pneumonia: ATS (1993), ATS (2001), IDSA (1998), IDSA (2000) and the guidelines of the Japan Respiratory Society (2000). One hundred community-acquired pneumonia patients admitted to the International Medical Center of Japan were investigated in accordance with each set of guidelines based on the physical, laboratory, and chest radiography findings on the first day of treatment. According to the ATS (1993) guidelines, 33% of the cases were classified as "severe" pneumonia. On the other hand, according to the ATS (2001) guidelines, only 8% of the cases were classified as "severe" pneumonia. According to the IDSA guidelines, 35% of the patients were classified as "outpatients". Fluoroquinolone appears to be a very important antibiotic drug in the new guidelines of both ATS and IDSA. The scoring system of IDSA suggested a correlation between the patient's score and the pathogenic bacteria. According to the guidelines of the Japan Respiratory Society, 42% of the cases were classified as "severe" pneumonia. There are evident differences between these guidelines, and clinicians need to have a full understanding of their respective characteristics.

Community-Acquired Infections↗