Search PubMed⌕ Search

Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 253 records · Page 14Linked to original sources
PubMed1994

DNA strand-breaking activities of quinolone antimicrobial agents under visible light irradiation.

The DNA strand-breaking activities of 9 quinolones, widely used as antimicrobial agents and suspected to induce photo-dermatological disorders in humans, were examined under irradiation using standard domestic fluorescent lamps. Two quinolones, tosufloxacin and enoxacin, converted the supercoiled covalently closed circular plasmid DNA to the open circular form under visible light irradiation. The maximum of photodynamic single strand-breaking activity for tosufloxacin was found to be 12% at 50 microM and that of enoxacin was 33% at a concentration of 2 mM. The DNA strand-breaking activities of photoirradiated tosufloxacin and enoxacin were markedly inhibited by NaN3 but only partially by D-mannitol, superoxide dismutase (SOD) and catalase did not inhibit these activities. These results suggest that some quinolone antimicrobial agents can be activated by visible light and induce phototoxic DNA damage in various organisms. We should carefully investigate such phototoxic activities during the development of new quinolones to avoid producing phototoxic disorders in man.

4-Quinolones↗
PubMed1994

Development and application of an enzyme immunoassay for karasurin A, an effective protein component of Trichosanthes kirilowii Max. var. japonicum Kitam.

A method was developed for specific estimation of the content of a non-enzymatic protein, karasurin A, in fractions taken during the extraction and purification processes from a natural source. Anti-karokon serum was elicited in rabbits immunized with fragments of karokon, a dried root tuber of Trichosanthes kirilowii Max. var. japonicum Kitam. Rabbit antibody specific for karasurin A was identified in anti-karokon serum by the Western blotting method. After separation by SDS-PAGE, protein bands of purified karasurin A and extracted proteins from a medicinal herb which is a karasurin A source were reacted with anti-karokon serum followed by treatment with horseradish peroxidase (HRP)-labeled Fab' of goat anti-rabbit IgG, and then bound HRP-labeled second antibody on protein bands was developed to brown by reaction with a substrate solution of the used enzyme. A novel selected antibody enzyme immunoassay (SAEIA) for karasurin A was developed using selective binding of anti-karasurin A antibody in anti-karokon serum to solid phase karasurin A and HRP-labeled Fab' of the second antibody as the tracer. Specific estimation of the content of karasurin A in several fractions taken during the isolation and purification processes of the protein were possible using the SAEIA method.

Animals↗
PubMed1994

[Clinical study of Mallory-Weiss syndrome in the aged patients over 75 year--mainly five cases induced by the endoscopic examination].

Cases of Mallory-Weiss syndrome aged over 75 year were analyzed with regard to their clinical features. In a 5-year period, there were 9 such cases, representing 19% of the total number of Mallory-Weiss syndrome cases. Four patients had a history of retching or vomiting, but in the other 5 patients, Mallory-Weiss tears occurred during endoscopic examination with slight vomiting reflex or even almost vomiting reflex. The latter cases had a spindle-shaped tear which was located on the lesser curvature at the cardia of the stomach. All patients were managed conservatively by observation without endoscopic hemostatic procedure, because the amount of bleeding was small. The 5 patients were thin and three of them had chronic atrophic gastritis. Mucosal weakness is an important etiologic factor in aged patients who develop Mallory-Weiss syndrome.

Aged↗
PubMed1994

[An experimental study on liver hyperthermia using intraperitoneal hyperthermic perfusion (IPHP)].

We evaluated the efficacy of intraperitoneal hyperthermic perfusion (IPHP) in regional hyperthermia of the liver. In white rabbits, an infusion catheter and a drainage catheter were placed in the Douglas pouch and upper abdominal cavity, respectively. Warm saline (46-48 degrees C) was infused into the abdominal cavity at a flow rate of 30-60 ml/min. The temperature was continuously monitored at seven measuring points including water bath, peritoneal inflow line, abdominal cavity, liver parenchyma, portal vein, rectum and esophagus. Temperature of the inflow line was maintained at 46-48 degrees C throughout the course. Temperature of the abdominal cavity reached 42.0-42.6 degrees C 30 minutes after the start of IPHP. The temperature of the portal vein reached 40.9 degrees C and 41.8 degrees C at 30 and 60 minutes, respectively. Liver parenchymal temperature increased to 41.5 degrees C and 42.1 degrees C at 30 and 60 minutes, respectively, indicating effective heating of the liver. On the other hand, the temperatures of the rectum and esophagus remained less than 39.2 degrees C and 40.4 degrees C throughout the course. Therefore, we consider that IPHP will be a simple and effective method for the performance of liver hyperthermia.

Animals↗
PubMed1994

[Experience in surgical management for active aortic valve endocarditis with periannular abscess--outcome of abscess cavity after patch closure].

Two patients with active aortic valve endocarditis and periannular abscess underwent surgical management. Both patients had bicuspid aortic valves. Involvement of the aortic annulus with the formation of the periannular abscess was found at one third circumference in the aortic annulus and extended to the sinuses of Valsalva. In one patient the periannular abscess ranged from the right side of the ostia of a left coronary artery to the right commissural region, and in another patient it existed at the left commissural region. the ostia of coronary arteries were separated from the inflammatory and necrotic tissue in both patients. The wall of periannular abscess could not be totally excised. Instead, debridement and transaortic patch closure of the abscess cavity were performed. In the former patient, partial resection of the aneurysmal wall of the abscess was performed and the remaining aortic wall was approximated with extra-luminal sutures supported by Teflon felt pledgets. However, in the latter patient, the plication of the abscess wall could not be performed. Prosthetic mechanical valve was implanted at the paraannular position by utilizing the patch. In the former patient it took a month and a half until the disappearance of the inflammatory reaction, and the echo free space could not be detected at the same place of the abscess cavity by the two-dimensional echocardiogram since early postoperative period. However, in the latter patient it took three months until the disappearance, and the echo free space had been existing at the same place for thirteen months after the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1993

Aflatoxin B1-binding proteins in primary cultured hepatocytes of chicken embryo: studies in vivo and in vitro.

Among several aflatoxin B1 (AFB1)-binding proteins in primary cultured hepatocytes of chicken embryo, a cytosolic 25 kDa protein proved to be an AFB1-specific binding protein. Binding of AFB1 to a cytosolic protein of the same molecular mass as that seen in vivo was also detectable in a cell-free system and was dependent on the microsomal components. The binding was observed in the in vitro systems derived from AFB1-sensitive animals such as chicken, rabbit, and rat. These findings suggest that the 25 kDa AFB1-binding protein(s) is involved in the intracellular process of AFB1-mediated toxicity.

Aflatoxin B1↗
PubMed1993

Automated high-performance liquid chromatographic method for determination of furosemide in dog plasma.

An automated high-performance liquid chromatographic method for the determination of the diuretic drug furosemide has been established. Dog plasma was injected directly into a two-column system with a BSA-ODS (ODS column coated with bovine serum albumin) precolumn and a C18 analytical column for the separation of furosemide. The two columns were automatically switched. Furosemide remained trapped on the precolumn while proteins were eluted to waste. After column switching, furosemide was washed onto the analytical column and analysed without interference. The greatest advantage of the method is its easy performance without manual sample preparation; it requires no extraction or deproteinization. The method allows determination of 0.1-10 micrograms/ml of furosemide with accuracy and precision comparable with previously reported values. The coefficients of variation obtained from replicate measurements of 1 microgram/ml and 5 micrograms/ml samples were 1.65% and 2.40%, respectively. This method was used to measure the plasma levels of furosemide in beagle dogs to whom the drugs was administered, as a reference, in a toxicological study.

Animals↗
PubMed1993

Ultraviolet resonance Raman spectra of pea intact, large, and small phytochromes: differences in molecular topography of the red- and far-red-absorbing forms.

Ultraviolet resonance Raman (UV RR) spectra excited at 244 nm were observed for pea intact, large, and small phytochromes at pH 7.8. Raman bands assignable to Trp residues dominated the UV RR spectra. The intensity ratios of Trp W7 doublet bands, I(1358)/I(1342), of all three phytochromes in the red light-absorbing form (Pr) were almost the same as that of an aqueous Trp solution, indicating that most of the six and four Trp residues in the 59-kDa chromophoric and the C-terminal 59-kDa nonchromophoric domains, respectively, reside in hydrophilic microenvironments in Pr. This ratio increased under red light illumination, where photoequilibria are attained between Pr and the far-red-absorbing form (Pfr) for intact and small phytochromes and among Pr, a bleached intermediate (Ibl), and Pfr for large phytochromes. The increase of the intensity ratio was most prominent for small phytochromes. These observations suggest that the microenvironments around some Trp residues become more hydrophobic due to conformational changes induced by phototransformation from Pr to Ibl and that the hydrophobicity increase occurs mainly in the chromophoric domain. Among the six Trp residues in the chromophoric domain, Trp365 and Trp567 are likely candidates for those involved in this hydrophobicity increase. The intensity distribution of the amide I band shows little beta-sheet in both Pr and Pfr of the intact, large, and small phytochromes and indicates that alpha-helices and nonregular structure are less populated in the chromophoric domain than in the N-terminal 6-kDa segment and the C-terminal nonchromophoric domain.

Fabaceae↗
PubMed1993

Determination of Fe-CO geometry in the subunits of carbonmonoxy hemoglobin M Boston using femtosecond infrared spectroscopy.

We have undertaken ultrafast infrared (IR) spectroscopic studies in order to elucidate the geometry of bound CO in the alpha and beta subunits of hemoglobin (Hb) M Boston 13CO. Hb M Boston is a mutant human Hb in which the distal histidine in the alpha subunits is replaced by a tyrosine. The IR absorptions of bound 13CO fall at 1925 cm-1 for the alpha subunits and 1907 cm-1 for the beta subunits. Despite a difference of nearly 20 cm-1 in these peaks, the measured anisotropies of the bound 13CO depletions following 30% photolysis are nearly identical, with values of -0.142 +/- 0.002 obtained for the alpha subunits and -0.140 +/- 0.003 obtained for the beta subunits. These translate to values of 20 degrees +/- 1 degree and 21 degrees +/- 1 degree for the values of the average angles between the CO bond and the normal to the heme planes in the alpha and beta subunits, respectively. Our present results and the work of previous investigators [Nagai, M., Yoneyama, Y., & Kitagawa, T. (1991) Biochemistry 30, 6495-6503] suggest that a change in the polar interactions of the bound CO with the heme pocket environment upon substitution of tyrosine for the distal histidine and a less bent structure for the Fe-C-O unit in the alpha subunits are responsible for the difference in the bound CO absorption frequencies in the alpha and beta subunits. A spectrum of the depletion of the bound 13CO peaks following photolysis indicates that both subunits photodissociate CO with the same quantum yield and neither subunit exhibits significant recombination within 1 ns.

Binding Sites↗
PubMed1993

Time-resolved resonance Raman study on the binding of carbon monoxide to recombinant human myoglobin and its distal histidine mutants.

Time-resolved resonance Raman (RR) spectra of the recombined species of photodissociated CO with recombinant human myoglobin (Mb) and several E7 mutants, in which distal His was replaced by Gly (H64G), Gln (H64Q), Ala (H64A), Ile (H64I), Val (H64V), and Leu (H64L) through site-directed mutagenesis, were observed in the time range -20 ns to 1 ms following photolysis. The Fe-CO stretching (VFe-CO) RR band was observed successfully with pulse excitation when the laser power was greatly reduced. H64H, H64G, and H64Q gave the VFe-CO band at 505-510 cm-1 in their stationary states. In their recovery processes 1-100 microseconds after photodissociation, a broad transient band was observed at slightly lower frequencies than those of their equilibrium structures for H64G and H64Q, but a transient VFe-CO band corresponding to the so-called "open" form was not identified around 490 cm-1 for any of the three species. A second group, H64A, H64I, H64V, and H64L, gave the main VFe-CO band at 490-495 cm-1 with a shoulder around 510 cm-1 (except for H64L) in the stationary state and exhibited a much faster recovery than the first group. These latter four species gave a broad transient band around 492-500 cm-1 in the time range of 100-1000 ns, while the approximately 510 cm-1 shoulder appeared much later. The equilibrium relative intensity of the two bands was attained at 500 microseconds, suggesting that the interconversion between the two forms is slower than 100 microseconds.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide↗
PubMed1993

Resonance Raman studies on the CuA site of cytochrome c oxidase using a multichannel scanning Raman spectrometer with a CCD detector.

A new Raman measurement system with a CCD (charge coupled device) detector was constructed and applied successfully to observe far-red excited Raman spectra of bovine cytochrome c oxidase. In resonance with the 830-nm absorption band, Raman bands were observed at around 330 cm-1 and assigned to the CuA-S(Cys) and CuA-N(His) stretching vibrations. Although the CuA center has been believed to be coupled with the other redox center and to serve as the electron acceptor from cytochrome c, the frequency and intensity of these bands were influenced by neither the redox and ligation changes in cytochrome alpha 3-CuB center nor the binding of cytochrome c, indicating the highly independent nature of the CuA center. In the higher frequency region of the far-red excited Raman spectra, some protein vibrations which could not be observed in resonance Raman spectra of heme proteins upon visible excitation were observed together with some preresonant heme modes. The amide I and III frequencies indicated a predominance of alpha-helix in the enzyme, and the amino hydrogens were scarcely exchanged with deuterons in D2O, while some Trp side chain bands clearly displayed the deuteration shift.

Animals↗
PubMed1993

Trans-activation of glutathione transferase P gene during chemical hepatocarcinogenesis of the rat.

Glutathione transferase P (GST-P; glutathione transferase, EC 2.5.1.18) is known to be specifically expressed at high levels in precancerous lesions and in hepatocellular carcinomas from a very early phase of chemically induced hepatocarcinogenesis in the rat. The almost invariable occurrence of this phenotype in these lesions strongly suggests a mechanism by which GST-P gene is activated together with a crucial transforming gene of liver cells. To distinguish the two alternative possibilities--either the GST-P gene is coactivated with a closely located transforming gene by a cis mechanism or it is activated in trans by a common trans-acting factor--we carried out carcinogenesis experiments using transgenic rats harboring the bacterial chloramphenicol acetyltransferase reporter gene ligated to the upstream regulatory sequence of the GST-P gene. In each of three independent lines tested, liver foci and nodules produced by chemical carcinogens (Solt-Farber procedure) were found to express high levels of chloramphenicol acetyltransferase activity, indicating clearly that the GST-P gene is activated by a trans mechanism during hepatocarcinogenesis.

Animals↗
PubMed1993

Frequent c-Ki-ras oncogene activation in mucous cell hyperplasias of pancreas suffering from chronic inflammation.

In order to scrutinize the possible significance of (nonatypical) mucous cell hyperplasia of the pancreas to neoplasia, we analyzed these lesions in terms of c-Ki-ras activation, which is known to be very frequent in pancreatic carcinomas. A total of 16 such mucous cell hyperplasias were collected from 10 pancreases resected for chronic pancreatitis. Tiny tissue fragments were taken from hematoxylin-stained sections by microdissection, and DNA analysis was carried out by the polymerase chain reaction amplification and oligonucleotide hybridization methods. Activating mutations of c-Ki-ras oncogene at codon 12 were detected in 10 of the 16 lesions (62.5%), a high rate as seen in carcinomas. The results indicated a clonal origin of cells comprising the mucous cell hyperplasia suggesting a neoplastic and/or precancerous nature.

Adult↗
PubMed1993

Modulation of the synthesis and glycosylation of the glucose transporter protein by transforming growth factor-beta 1 in Swiss 3T3 fibroblasts.

Transforming growth factor-beta 1 (TGF-beta 1) stimulated growth and glucose uptake in Swiss mouse fibroblasts. DNA synthesis was increased 2-3-fold after 48 h incubation of growing 3T3 cells with TGF-beta 1 in calf serum-containing medium. Glucose transport activity in the cells was increased within 3 h after addition of TGF-beta 1 and this stimulation continued during incubation for 48 h. TGF-beta 1 also increased the levels of a brain type-glucose transporter (GLUT1) mRNA and the GLUT1 protein (55 kDa) in the membranes, consistent with the increase in glucose uptake. Furthermore, a longer exposure of TGF-beta 1 for 24-48 h induced a marked increase in the 65 kDa GLUT1 in 3T3 cell membranes. Other growth factors such as epidermal growth factor, fibroblast growth factor, transforming growth factor-alpha, and insulin did not elevate glucose uptake and the levels of 55 and 65 kDa GLUT1 proteins. Adding tunicamycin or deoxymannojirimycin to the TGF-beta 1-treated and untreated cells caused these 55 and 65 kDa glucose transporters to migrate as one band at 40-43 kDa. In addition, treating membrane proteins with glycopeptidase F, which removes N-linked oligosaccharides, also generated a glucose transporter of 40 kDa, suggesting that the 55 and 65 kDa GLUT1 proteins have a similar or identical core polypeptide but with different N-linked oligosaccharides. These results indicate that TGF-beta 1 modulates the synthesis of GLUT1 protein as well as its glycosylation in Swiss 3T3 cells, and that these changes may contribute to the control of cell proliferation by TGF-beta 1.

3T3 Cells↗
PubMed1993

Roles of proximal ligand in heme proteins: replacement of proximal histidine of human myoglobin with cysteine and tyrosine by site-directed mutagenesis as models for P-450, chloroperoxidase, and catalase.

Histidine-93(F8) in human myoglobin (Mb), which is the proximal ligand of the heme iron, has been replaced with cysteine or tyrosine by site-directed mutagenesis. The resultant proximal cysteine and tyrosine mutant Mbs (H93C and H93Y Mbs, respectively) exhibit the altered axial ligation analogous to P-450, chloroperoxidase, and catalase. Coordination of cysteine or tyrosine to the ferric heme iron is confirmed by spectroscopic measurements including electronic absorption, hyperfine-shifted 1H-NMR, EPR, resonance Raman spectroscopies, and redox potential measurements of ferric/ferrous couple. H93C Mb is five-coordinate ferric high-spin with the proximal cysteine. H93Y Mb bearing the proximal tyrosine ligated to the iron is also in a ferric high-spin, five-coordinate state. The reactions of the mutants with cumene hydroperoxide show that the thiolate ligand enhances heterolytic O-O bond cleavage of the oxidant, while the phenolate ligand hardly affects the heterolysis/homolysis ratio for O-O bond scission in comparison with wild-type Mb. Monooxygenase activities such as epoxidation of styrene and N-demethylation of N,N-dimethylaniline, and catalase activity (dismutation of hydrogen peroxide) by wild-type Mb and the mutants, are examined by using H2O2. The increase of the catalytic activities by the mutation was, at most, 5-fold in the epoxidation reaction.

Benzene Derivatives↗