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Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 307 records · Page 17Linked to original sources
PubMed1992

Observation of the FeIV=O stretching Raman band for a thiolate-ligated heme protein. Compound I of chloroperoxidase.

The FeIV=O stretching vibration has never been identified for a cysteine-coordinated heme enzyme. In this study, resonance Raman and visible absorption spectra were observed simultaneously for transient species in the catalytic reaction of chloroperoxidase with hydrogen peroxide by using our original apparatus for mixed-flow and Raman/absorption simultaneous measurements. For the first intermediate, the FeIV=O stretching Raman band was observed at 790 cm-1, which shifted to 756 cm-1 with the 18O derivative, but the v4 band was too weak to be identified. This suggested the formation of an oxoferryl porphyrin pi cation radical. The second intermediate gave an intense v4 band at 1,372 cm-1 but no oxygen isotope-sensitive Raman band, suggesting oxygen exchange with bulk water.

Chloride Peroxidase↗
PubMed1992

The primary structure of mouse saposin.

The primary structure of mouse sphingolipid activator protein (saposin) was determined by cDNA sequencing. The amino acid sequence predicted by the cDNA sequence revealed that mouse saposin was highly homologous to human saposin and also to rat sertoli cell glycoprotein. Mouse saposin also has four functional domains, which are structurally similar to each other, and each domain has cysteines, prolines, and a potential glycosylation site at an almost identical position. An amino acid comparison between human and mouse saposins revealed that the similarity was approximately 70%, and human saposin lacks thirty-one amino acids between domains C and D. Heterogeneities of mRNA were found in both the coding and noncoding regions.

Amino Acid Sequence↗
PubMed1992

Allelotype of non-small cell lung carcinoma--comparison between loss of heterozygosity in squamous cell carcinoma and adenocarcinoma.

We examined loss of heterozygosity (LOH) on all autosomal chromosomes in 53 non-small cell lung carcinomas. Frequent LOH was observed on the long arms of chromosomes 1 (37%), 2 (31%), 5 (30%), 8 (31%), and 13 (32%), and the short arms of chromosomes 3 (54%) and 17 (62%). LOH on chromosomes 3p and 17p was observed in all informative cases of squamous cell carcinoma, but was significantly less frequent in adenocarcinomas (P = 0.003 and 0.001, respectively). Similarly, LOH on chromosome 13q was observed frequently in squamous cell carcinomas (5 of 9 informative cases, or 56%), but in only 5 of 26, or 19%, of adenocarcinomas. In contrast, LOH on chromosome 2q was observed only in adenocarcinomas. In addition, this chromosomal arm was lost more frequently in poorly differentiated, compared to well differentiated adenocarcinomas. Furthermore, a correlation between fractional allelic loss and pathohistological grade was identified. These results implicate the presence of several tumor suppressor genes associated with development and/or progression of non-small cell lung carcinomas.

Adenocarcinoma↗
PubMed1992

Site-directed mutagenesis in hemoglobin: functional and structural role of inter- and intrasubunit hydrogen bonds as studied with 37 beta and 145 beta mutations.

In order to clarify the functional and structural role of intra- and intersubunit hydrogen bonds in human hemoglobin (Hb A), we prepared two artificial beta chain mutant hemoglobins by site-directed mutagenesis. The mutant Hb Phe-37 beta, in which Trp-37 beta is replaced by Phe to remove the intersubunit hydrogen bond between Asp-94 alpha and Trp-37 beta at the alpha 1-beta 2 interface in deoxy Hb A, showed a markedly increased oxygen affinity and almost completely diminished Bohr effect and cooperativity. However, 1H-NMR data indicated that the structure of deoxy Hb Phe-37 beta is rather similar to that of deoxy Hb A. The enhanced tetramer-to-dimer dissociation previously observed in Hb Hirose (Trp-37 beta----Ser) together with our observation of the effects of organic phosphate on the structure and function of Hb Phe-37 beta suggested that a large part of the abnormal properties of Hb Phe-37 beta observed for dilute solutions appears to result from partial dissociation into alpha beta dimers rather than direct destabilization of the T-quaternary structure in the deoxygenated state. Thus, the primary and direct role of the hydrogen bond between Asp-94 alpha and Trp-37 beta is to stabilize the tetrameric assembly, and thereby this hydrogen bond indirectly contributes to stabilization of the T-quaternary structure. The other mutant Hb Phe-145 beta has a Phe residue at the 145 beta site and lacks the intrasubunit hydrogen bond formed between Tyr-145 beta and the carbonyl group of Val-98 beta in deoxy Hb A.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

A clinicopathological and immunohistochemical study of osteofibrous dysplasia, differentiated adamantinoma, and adamantinoma of long bones.

A clinicopathological and immunohistochemical study of 12 cases of osteofibrous dysplasia (OFD), two cases of differentiated adamantinoma, and five cases of adamantinoma of long bones is presented. Although OFD and differentiated adamantinoma showed similar radiologic findings, differentiated adamantinoma was more likely to be a recurrent lesion than osteofibrous dysplasia and seemed to require a more extensive surgical procedure. Immunohistochemically, cytokeratin- and vimentin-positive cells were seen in both OFD and differentiated adamantinoma. The positive cells were scattered in the former, and were both scattered and nest-like in the latter. Both these lesions, however, were negative for epithelial membrane antigen. Excluding two cases of Ewing-like adamantinoma, the other three cases of adamantinoma were also positive for cytokeratin and vimentin. These results suggest that these three lesions share the same histogenetic origin. The two cases of Ewing-like adamantinoma differ from tibial adamantinoma in their radiological, histological and immunohistochemical aspects, and seem to constitute a distinct variant of adamantinoma with a different histogenesis.

Adolescent↗
PubMed1992

Aggressive resection for advanced pancreatic carcinoma.

An aggressive pancreatectomy was performed on a 53 year old Japanese man with advanced cancer of the pancreas. The tumor originated from the body of the pancreas and invaded the stomach, duodenum, left kidney, transverse colon and common hepatic artery. An unexpected cancer was also found in the head of the pancreas during the operation. Therefore, total pancreatectomy, total gastrectomy, left adrenonephrectomy, resection of the left transverse colon and dissection of the regional lymph nodes were performed. Resection of the common hepatic artery was also performed, followed by an end-to-end anastomosis between the common hepatic artery and celiac trunk. The postoperative course was uneventful and the patient was doing well until nine months after the operation when multiple metastatic lesions were noted in the liver. He died 391 days after the operation from hepatic failure.

Adenocarcinoma↗
PubMed1992

Measurement of beta 2 microglobulin in dried urine spotted on filter paper by means of a forward sandwich enzyme-linked immunosorbent assay.

We devised a highly sensitive forward sandwich enzyme-linked immunosorbent assay (ELISA) for estimation of the beta 2-microglobulin concentration in dried urine spotted on filter paper. This method is suitable for mass screening because of the good reproducibility, satisfactory stability, low operation cost and easy sample collection. However, preliminary studies using our new method for detecting renal diseases in the Tokyo infant population did not produce good results. The high cut-off value may have been the main reason. To make this ELISA more suitable for mass screening, we plan to reduce the cut-off value, test older children and improve the extraction step.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Frequent spontaneous sister chromatid exchange in hepatocytes of transgenic mice harboring the SV40-T antigen gene.

In order to shed light on the causal mechanisms of hepatocarcinogenesis in the transgenic mouse into which the albumin-promotor-regulated SV40-T antigen gene has been introduced (T+ mouse), and especially on the frequent chromosomal aberrations seen in cultured hepatocytes and hepatocellular neoplasms derived from such animals, the frequency of sister chromatid exchange (SCE) and karyotype abnormalities were investigated in a hepatocyte primary culture system. Cells were obtained through collagenase perfusion from T+ mice at 16-18 days of age, when no morphological changes are apparent, and from nontransgenic littermates, and cultured in the presence of bromodeoxyuridine. SCE was seen in transgenic hepatocytes twice as frequently as in their normal counterparts. No karyotype abnormalities in terms of numerical change or gross aberration were detected at this phase. The results thus suggest mutagenic properties for the T antigen, which may play an important role in hepatocarcinogenesis in this transgenic mouse.

Animals↗
PubMed1992

Changes in plasma free and sulfoconjugated catecholamines before and after acute physical exercise: experimental and clinical studies.

To elucidate whether sulfoconjugated catecholamines in plasma, especially dopamine, serve as a source of free catecholamines, we examined the change in afterload on the deconjugating activity of catecholamines in isolated Langendorff perfused rat hearts. Dopamine-sulfate was administered under ordinary or high-work-load conditions. Free dopamine in the effluent was increased by the high-work-load of the hearts, whereas conjugated dopamine showed an apparent decrease. These results indicate the possibility that deconjugation of sulfoconjugated catecholamines is accelerated by a high-work-load. To obtain further evidence in humans, we also examined the changes in the plasma levels of free and sulfoconjugated catecholamines in healthy volunteers before and after marathon running. Free dopamine increased 1.99-fold from the baseline value after exercise, whereas conjugated dopamine decreased by 12%. Similarly, the plasma levels of free noradrenaline and adrenaline increased after exercise to 2.45- and 1.51-fold their respective baseline values, while conjugated noradrenaline and adrenaline both decreased. These clinical results, as well as those of the experimental studies, suggest that the increase in plasma free catecholamines after exercise is due not only to increased release from the sympathoadrenal system but also to accelerated conversion from sulfoconjugated catecholamines in the plasma.

Adolescent↗
PubMed1992

Investigation of higher order structures of proteins by ultraviolet resonance Raman spectroscopy.

Progress in laser technology and light detection devices have enabled us to explore protein structures and their dynamics by using time-resolved resonance Raman spectroscopy. It is in the last decade that Raman spectra of proteins excited at 200-240 nm have brought about rich structural information. The technological developments in deep UV resonance Raman spectroscopy are reviewed first, and the unique information on proteins obtainable from such spectra are summarized. As an application of this technique to investigations of the higher order structures of proteins, studies on the quaternary structure transition of haemoglobin are described.

Amino Acid Sequence↗
PubMed1992

Indications of particle radiation therapy in the treatment of carcinoma of the esophagus.

Studies were made to evaluate the role of radiations in the treatment of carcinoma of the esophagus to confirm indications for charged particles. Results of the studies showed that prognosis of the patients treated with radiations depend strongly on length of tumor as well as on invasion of tumor cells into the adventitia of the esophagus. It was concluded that patients suffering from carcinoma of the esophagus less than 8 cm length are indicated for particle radiations.

Esophageal Neoplasms↗
PubMed1992

Detection and quantitative assessment of a Vibrio cholerae O1 species in several foods by a novel enzyme immunoassay.

A selected antibody enzyme immunoassay (SAEIA) for the general detection of Vibrio cholerae O1 species has been developed using the immunological reagents of a rabbit antiserum specific for V. cholerae O1 classical Inaba 569B and immobilized cell fragments of V. cholerae O1 El Tor 85P6, and beta-D-galactosidase-labeled goat anti-rabbit immunoglobulin G as tracer. The SAEIA was specific for V. cholerae O1 species and showed low cross-reaction values to other microorganism species tested including Vibrio parahaemolyticus. The detection limit of the SAEIA was 4,500 cells per assay for all the 13 strains of V. cholerae O1 examined. Quantitative comparison on the growth of the El Tor 85P4 in several foods cultured for 24 hr were studied using the SAEIA. Preceding the experiments, little inhibition of every food homogenate for the measurement of the SAEIA was first demonstrated and then the homogenate was directly used for an assay sample. The interaction of the growth of Escherichia coli to that of V. cholerae O1 in a food was also found to be little under the mixed culturing of both bacteria using the SAEIA.

Escherichia coli↗
PubMed1992

Site-dependent development of complete and incomplete intestinal metaplasia types in the human stomach.

The topographical distribution of complete and incomplete types of intestinal metaplasia in human stomach samples was investigated in order to elucidate their mutual histogenetic relationship and significance in carcinogenesis. Subgross stereomicroscopic examination of alcian blue and hematoxylin-stained gastric mucosae allowed clear distinction of complete and incomplete intestinal metaplasia types as white (with or without purple hue) and purple foci, respectively, against the background magenta areas of non-intestinalized mucosa. Intestinal metaplasias which developed in the fundic area were predominantly of the complete type whereas those of the antrum were a mixture of both with a distinct predilection for expression of the incomplete type. Although there was some variation among foci regarding the hue of white or purple, the color feature was principally homogeneous within each individual intestinal metaplasia focus. Thus phenotypic analysis indicated intestinal metaplasia expression to be clearly influenced by intragastric topography. The study did not provide any evidence that a shift from incomplete to complete type intestinal metaplasia may occur with time or that the incomplete type may be more intimately associated with development of well-differentiated carcinomas.

Adult↗
PubMed1992

Modulation of membrane permeability, cell proliferation and cytotoxicity of antitumor agents by external ATP in mouse tumor cells.

External ATP causes a remarkable change in the passive permeability of the plasma membrane in several types of transformed cells. When mouse melanoma cells, Clone-M3, were exposed to ATP in Tris-buffered saline, a great increase in the passive permeability was induced within several minutes. Longer exposure of Clone-M3 cells to external ATP led to a decrease in cell viability. Similar results were obtained with Ehrlich ascites cells, but none of these ATP effects were noted in untransformed cells such as NIH 3T3 cells or BALB/c mouse embryonic fibroblasts. The in vitro cytotoxic effects of antitumor agents (5-fluorouracil, adriamycin, mitomycin C and nimustine hydrochloride) against Clone-M3 cells were additively potentiated by treatment with external ATP, which also synergistically enhanced the cytotoxicity of vincristine. However, the effects of these drugs on mouse embryonic fibroblasts were not modulated by ATP. These results suggest that ATP-treatment is a useful means of enhancing a selective toxicity for tumor cells.

3T3 Cells↗
PubMed1992

Unusual huge intramuscular granuloma with calcium phosphate crystal deposition in the buttock.

An unusual case of a huge granuloma featuring marked calcium phosphate crystal deposition in muscle is presented. A 58-year-old male demonstrated a well-circumscribed, large, elastic firm mass which had slowly grown over 8 years in the left buttock. Clinical examinations including X-ray, ultrasonography and computed tomography all suggested a neoplastic growth. Surgical excision revealed three inter-connected irregular-shaped masses, measuring up to 11 x 10 x 6 cm in size. The histological appearance was of granulomas composed of numerous small crystals surrounded by reactive mononuclear cells embedded in fibrous tissue containing many foreign body type giant cells. Chemical analysis demonstrated the crystals to be made up of calcium phosphate.

Buttocks↗
PubMed1992

Effect of antacid on absorption of the quinolone lomefloxacin.

The effect of antacid on the absorption of lomefloxacin (LFLX) in humans was studied. When LFLX was orally administered concomitantly with aluminum- and magnesium-containing antacids under fasting conditions, its level in plasma decreased by one-half and its area under the concentration-time curve was reduced by 40% compared with the levels observed after treatment with LFLX alone. The urinary recovery value also decreased by 40%. No such effects were noted after coadministration of LFLX and a nonmetallic antacid. This study confirmed the existence of chelate complexes of LFLX with Al3+ and Mg2+ and examined the chelating strength. The stability constants of LFLX with Al3+ and Mg2+ were measured and compared with those of ofloxacin and norfloxacin; little difference was observed among them. LFLX was found to bind more strongly with Al3+ than with Mg2+. Further, the existence of chelate formation was proven by 13C-nuclear magnetic resonance spectroscopy. The decrease in the LFLX level in plasma in humans could be explained by a reduced absorption of the Al(3+)- and Mg(2+)-LFLX chelate complexes.

Adult↗