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Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 145 records · Page 8Linked to original sources
PubMed1998

Epostatin, new inhibitor of dipeptidyl peptidase II, produced by Streptomyces sp. MJ995-OF5. I. Taxonomy of producing strain, fermentation, isolation, physico-chemical properties and biological properties.

A new inhibitor of dipeptidyl peptidase II (DPP-II, EC 3.4.14.2), designated as epostatin, was discovered in the fermentation broth of a strain isolated in our institute. The strain has been identified as Streptomyces sp. MJ995-OF5 on the basis of taxonomic studies. Epostatin was obtained as a yellow powder after seqential purification by chromatography on Diaion HP-20, n-butanol extraction, Sephadex LH-20 column chromatography and centrifugal partition chromatography (CPC). Epostatin inhibited DPP-II competitively in a dose dependent manner. The compound was slightly inhibitory against other dipeptidyl peptidases.

Alanine↗
PubMed1998

Effect of a novel antibiotic, heliquinomycin, on DNA helicase and cell growth.

Heliquinomycin, a novel microbial product, was found to inhibit a human DNA helicase enzyme isolated from HeLa S3 cells at concentrations of 5 to 10 micrograms/ml. In contrast, adriamycin, etoposide and cisplatin did not inhibit this enzyme at the concentrations tested. Furthermore, the replication and repair of SV40 chromosome were not affected at heliquinomycin concentration of 50 micrograms/ml. The topoisomerase II and I enzymes were inhibited at 30 micrograms/ml and 100 micrograms/ml of heliquinomycin, respectively. Heliquinomycin inhibited the growth of HeLa S3, KB, LS180, K562 and HL60 human tumor cell lines at IC50 values of 0.96 to 2.8 micrograms/ml. In addition, the growth of adriamycin and cisplatin resistant P388 cell lines were inhibited at similar concentrations. Heliquinomycin inhibited both DNA and RNA synthesis in cell culture but did not inhibit protein synthesis. HeLa S3 cells were arrested at the G2/M phase by heliquinomycin. These studies suggest that heliquinomycin is a selective inhibitor of a cellular DNA helicase and in turn, inhibits growth of tumor cell lines.

Antibiotics, Antineoplastic↗
PubMed1998

Fluostatins A and B, new inhibitors of dipeptidyl peptidase III, produced by Streptomyces sp. TA-3391. I. Taxonomy of producing strain, production, isolation, physico-chemical properties and biological properties.

New inhibitors of dipeptidyl peptidaseIII (EC 3.4.14.4) from human placenta, designated as fluostatins A and B, were discovered in the fermentation broth of a strain isolated in our institute. The strain has been identified as Streptomyces sp. TA-3391 on the basis of taxonomic studies. Fluostatins A and B were purified by Diaion HP-20 chromatography, ethyl acetate extraction, silica gel chromatography and reverse phase preparative HPLC. With the synthetic substrate, arginyl-arginine-2-naphthylamide, the IC50 values of fluostatins A and B were 0.44 and 24.0 micrograms/ml, respectively. Fluostatins A and B were slightly inhibitory against other dipeptidyl peptidases. Fluostatin A showed mixed-type (competitive and noncompeptitive) inhibition with human leucine-enkephalin as a substrate, and the inhibition constant (Ki) was 14.2 microM.

Chromatography, High Pressure Liquid↗
PubMed1998

MJ347-81F4 A & B, novel antibiotics from Amycolatopsis sp.: taxonomic characteristics, fermentation, and antimicrobial activity.

Strain MJ347-81F4 has been found to produce two new cyclic thiazolyl peptide antibiotics, components A and B. Taxonomic studies including morphological and physiological characteristics and chemical analysis of whole cells of the producing strain revealed this microorganism to belong to genus Amycolatopsis, and so we designated the strain Amycolatopsis sp. MJ347-81F4. After 10 to 12 days of fermentation, most of the antibacterial activity was present mainly in the mycelial cake and reached its maximum level. In comparison with reference compounds, A as the major component showed excellent in vitro activity against gram-positive bacteria including highly methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis with MICs in the range of concentration of 0.006 to to approximately 0.1 microg/ml. The results on the antimicrobial activity against thiazolyl peptide-resistant mutants of Bacillus subtilis NRRL B-558 indicated that the possible molecular target of MJ347-81F4 component A might be the 50S subunits of the ribosome, the inactivation of which would inhibit protein synthesis.

Anti-Bacterial Agents↗
PubMed1998

[Clinical results of transurethral ureterolithotripsy using pulsed-dye laser: primary ureteral stones versus secondary ureteral stones after ESWL].

Between September 1993 and December 1996, 138 patients underwent transurethral ureterolithotripsy (TUL) either as primary treatment or as a second-line therapy after extracorporeal shock wave lithotripsy. In all patients, a semirigid 6.0 F ureteroscope was used. Lithotripsy was performed using a pulsed-dye laser. The overall success rate was 82.6%. The success rates according to the location of stones were as follows, 76.9% for stones in the upper ureter (U1), 96.0% for those in the midureter (U2), and 86.2% for those in the distal ureter (U3). In 68 patients treated with TUL as primary therapy, the success rate was 88.2% and efficiency quotient, which was modified for TUL was 0.75. Complications were rare: no ureteral perforations and no major bleeding occurred, but urosepsis developed in 2 patients. In conclusion, transurethral ureterolithotripsy using a small caliber ureteroscope with pulsed-dye laser is recommended as the primary treatment for mid- and distal ureteral stones, because of its superior success rate. In addition, for upper ureteral stones, laser tripsy is recommended as a helpful auxiliary procedure.

Adolescent↗
PubMed1998

Lecithin-bound superoxide dismutase in the prevention of neutrophil-induced damage of corneal tissue.

PURPOSE: To evaluate the effects of a lipophilic analog of superoxide dismutase (SOD) in the prevention of polymorphonuclear leukocyte (PMN)-induced damage to corneal epithelial cells in vitro and in bacterial corneal ulcers in vivo. METHODS: Immortalized human corneal epithelial cells (T-HCEC) were cocultured with human PMNs activated with N-formyl-methionyl-leucyl-phenylalanine for 18 hours, after which lactate dehydrogenase (LDH) activity of the supernatant was measured as a marker of cellular damage. The inhibitory effects of lecithin-bound SOD (PC-SOD) and unmodified SOD, as well as PMNs pretreated with anti-CD 18 monoclonal antibody, were compared with untreated control. The retention of each drug on the ocular surface of healthy volunteers was measured by flow cytometry using brush cytology samples. The protective effects of a 0.1% solution of PC-SOD on Pseudomonas aeruginosa corneal infection in guinea pigs were assessed by inflammatory grading scores and histology. RESULTS: Both PC-SOD and SOD effectively suppressed PMN-induced LDH release in T-HCEC in a dose-dependent manner. LDH release was also attenuated when PMNs were pretreated with anti-CD 18 antibodies, suggesting that adhesion molecules were involved in the process. Brush cytology of conjunctival samples showed that PC-SOD was retained longer on the ocular surface compared with unmodified SOD. PC-SOD significantly prevented excessive tissue damage by infiltrating PMNs in P. aeruginosa corneal infection, whereas in control eyes, perforation of the cornea occurred by 6 days. CONCLUSIONS: PC-SOD was effective in attenuating PMN-related tissue damage to corneal tissue both in vitro and in P. aeruginosa infection in guinea pigs.

Animals↗
PubMed1998

[Sleep paralysis].

According to ICSD criteria, sleep paralysis (SP) occurs at least once in a lifetime in 40-50% of normal subjects. Variation in the reported incidence could be attributed to the difference in the expression in survey or an influence of cultural background. Some factors assumed to affect the appearance of SP include psychological, biological, developmental, and genetic influences. Sleep onset REM period (SOREMP) is one of the factors which is 'assumed to be related to SP in normal subjects' as well as narcoleptic patients. We conducted an experiment for eliciting SOREMP and SP. Our result indicated a relationship between SOREMP and SP. Polysomnograms during SP were characterized by REM/W stage dissociated states. Other factors which may influence the occurrence of SP are also discussed.

Humans↗
PubMed1998

[Monoclonal antibodies as an immunotherapy of rheumatoid arthritis].

Rheumatoid arthritis(RA) is a chronic, deforming and destructive arthritis of unknown etiology. For the medical treatment of RA, NSAID has been the first choice of drug. Recently it has been known that early use of DMARD may result in clinical remission. Understanding of the pivotal role of cytokines and adhesion molecules for the rheumatoid joint destruction enabled us to target these cytokines and molecules as therapeutic measures. Monoclonal antibodies were produced against the cytokines and adhesion molecules such as IL-1, IL-6, IL-6R, TNF-alpha, as well as CD4 molecules. Clinical use of these monoclonal antibodies was found to be effective for rheumatoid arthritis. However these therapeutic measures have several disadvantages such as transient efficacy and side effect.

Antibodies, Monoclonal↗
PubMed1998

Decreased Fcgamma receptor III (CD16) expression on peripheral blood mononuclear cells in patients with Sjögren's syndrome.

OBJECTIVE: To examine the expression of surface structures important in natural killer (NK) cell function and the roles of serum factors affecting the expression of surface antigens on these cells in patients with Sjögren's syndrome (SS). METHODS: Peripheral blood mononuclear cells (PBMC) of 18 patients with SS were analyzed by immunofluorescence on a flow cytometer. The antigen recognized by autoantibodies in their sera was analyzed by immunofluorescence and by immunoprecipitation. RESULTS: Expression of Fcgamma receptor III (CD16), an important indicator of NK cytolytic activity, on PBMC was significantly decreased in patients with SS who have extraglandular disease, while the expression of Fcgamma RI and II was normal. Moreover, F(ab')2 of IgG in these patients' sera was shown to bind to CD16+ cells. Immunoprecipitation study showed that it bound to CD16 itself. CONCLUSION: The depressed expression of CD16 on PBMC and the presence of antibody binding to CD16 in the patients' sera may be, at least in part, responsible for the altered function of NK cells observed in SS.

Adult↗
PubMed1998

[Two cases of complete atrioventricular canal defect whose pulmonary vascular resistance were over 10 wood unit.m2 before 6 months of age].

We report two cases with complete form of atrioventricular canal defect (CAVCD) accompanied by Down's syndrome whose pulmonary vascular resistance (Rp) were more than 10 Wood unit.m2 at the age of less than 6 months. One child was 3-month-old boy whose Rp was 12 Wood unit.m2. The open lung biopsy at 3 months old showed histopathological change of Heath-Edwards grade I. He underwent intracardiac repair at the age of 4 months. He is doing well at 30 months of postoperative period. Another child was 5-month-old girl whose Rp was 15.5 Wood unit.m2. Histopathological change of lung at 5 months old demonstrated Heath-Edwards grade III. She underwent intracardiac repair at the age of 7 months, 2 months after lung biopsy. However, she died of oversystemic pulmonary hypertension and low output syndrome 7 days after surgery. The postmortem examination revealed that pulmonary vascular obstructive disease progressed during 2 months interval between the lung biopsy and the operation. In conclusion, cardiac catheterization with estimation of Rp should be performed in the cases of CAVCD, especially in those with Down's syndrome, in early infancy. If Rp is more than 10 Wood unit.m2 and lung biopsy indicates the surgical indication, surgical intervention should be done as soon as possible since the pulmonary vascular obstructive disease may progress in a short period.

Endocardial Cushion Defects↗
PubMed1998

Analysis of the electroencephalogram in growing calves by use of power spectrum and cross correlation.

OBJECTIVE: To determine postnatal maturation of findings in the electroencephalogram (EEG) of calves and estimate the degree of electrophysiologic activity, using power spectrum and cross-correlation analyses of the EEG. ANIMALS: 10 clinically normal Japanese Black calves ranging in age from 1 to 10 weeks. PROCEDURE: EEG were recorded at various stages of consciousness. Power spectrum and cross-correlation analyses were applied to a relaxed state EEG. RESULTS: After the second week of age, rhythmic waves with frequencies of 6 to 9 Hz (alpha rhythm-like pattern) appeared in the EEG during the relaxed state, and were recorded in the occipital and vertex areas; duration of appearance was < 30 seconds. By use of power spectrum analysis, power distribution of the 7.5- to 10-Hz frequency band in the occipital area significantly increased after the sixth week. The highest frequency (18 to 30 Hz) band increased in the frontal and occipital areas after the seventh week. Normalized cross-correlation coefficients at 0 time shift were > 0.6 throughout the experimental period. The normalized cross-correlation coefficients obtained from caudal interhemispheric sites increased after the second week, and were significantly greater than those in rostral sites. CONCLUSIONS AND CLINICAL RELEVANCE: Developmental changes in the EEG of calves during the first 10 weeks could be characterized by appearance of the alpha rhythm-like pattern and increase of the power distributions of the 7.5- to 10-Hz and 18- to 30-Hz frequency bands, which might be a useful indicator for estimating brain activity in young calves and as standard data for evaluating abnormal brain activity in calves.

Aging↗
PubMed1998

[One-stage repair of interrupted aortic arch with selective cerebral perfusion].

To minimize the neurological compromise after the circulatory arrest, the selective cerebral perfusion could be beneficial. We underwent one-stage repair of the interrupted aortic arch (IAA) with various intracardiac anomalies for the six patients, age ranging from 12 days to 4 months, by using the selective cerebral perfusion. Cardiopulmonary bypass was established by using two-way arterial cannulation supported by the two respective pump systems, one of which utilized the EPTFE graft anastmosed to either the bracheocephalic artery or the right subclavian artery and second of which enrouted through the arterial ductus to the descending aorta. The cerebral perfusion during the circulatory arrest for the aortic arch repair was maintained by the selective perfusion via EPTFE graft with 10 ml/kg/min blood flow. After the completion of the arch repair, the total system perfusion was restarted through the graft and the repair of the intracardiac anomalies was followed. Of six, no operative death or neurological complications related to the operation were found. The clinical neurological evaluation after operation also demonstrated the normal for the age. In conclusion, the selective cerebral perfusion by using the EPTFE graft during the circulatory arrest might decrease the risk of brain damage.

Aorta, Thoracic↗
PubMed1998

[A case of renal pelvic cancer with recurrence of liver metastasis showing partial response by injection of methotrexate and intraarterial infusion of cisplatin and pirarubicin].

The patient was a 71-year-old man who had been diagnosed as having a left renal pelvic cancer with liver metastasis. We performed total left nephroureterectomy with lymphnode cleaning and partial resection of the liver. Because abdominal CT 5 months after the operation revealed multiple metastasis of the liver, we performed chemotherapy with a regimen consisting of methotrexate 50 mg (intravenous injection), cisplatin 30 mg and pirarubicin 20 mg (intraarterial infusion), and leucovorin 3 mg (intramuscular injection), three times at intervals of 6 hours. Ten days after chemotherapy, CT revealed the disappearance of most of the liver metastatic lesions, and a partial response was obtained. We are now performing the regimen at an interval of a month to a month and one-half to control the metastatic lesions.

Aged↗
PubMed1998

Respiratory syncytial virus-induced interleukin-4 production by human conjunctival epithelial cells contributes to allergy: preliminary study.

PURPOSE: We previously reported allergic conjunctivitis was associated with a local pattern of cytokines and identified respiratory syncytial virus (RSV) in the conjunctival epithelium, in patients with allergic conjunctivitis. We hypothesized that RSV infected the normal conjunctival epithelium and produced interleukin-4 (IL-4), causing an allergic reaction. To determine this event, we studied production of IL-4 by human conjunctival epithelial cells, after infection with RSV. METHODS: Conjunctival samples were collected with a special brush and were challenged with 5 x 10(6) pfu/ml of live RSV. RSV infection was detected by immunocytochemical study and RT-PCR. HLA-DR antigen was expressed by flow cytometry. IL-4 was assayed by a sandwich ELISA. RESULTS: Immunocytochemical study and RT-PCR showed that RSV infected the conjunctival epithelial cells. HLA-DR was demonstrated in the RSV-infected conjunctival epithelial cells. Average concentrations of IL-4 in culture supernatants in infected cells were 3.8 +/- 1.8, 3.6 +/- 1.1, and 5.4 +/- 1.8 pg/ml at 24, 48, and 72 h, respectively. Levels in non-infected cells were 0.33 +/- 0.0, 0.59 +/- 0.69, and 0.4 +/- 0.22 pg/ml, respectively (p > 0.001). CONCLUSION: Findings suggest that the expression of IL-4 is associated with intracellular infection by RSV in conjunctiva. With our former reports, RSV infection in conjunctival epithelial cells can be suggested as one of the possible environmental pathogens of allergic conjunctivitis.

Adolescent↗