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K Imai

Publications and source records attributed to K Imai.

At least 1,099 records · Page 61Linked to original sources
PubMed1990

[Carcinoembryonic antigen gene family and its clinical application].

Carcinoembryonic antigen (CEA) gene was cloned in 1987. Thereafter, the structures of non-specific cross-reacting antigen (NCA) and biliary glycoprotein I (BGPI) have also been clarified. These three antigens contain immunoglobulin-like domains in their basic structures and it could be possible that CEA gene was originated from this basic structure by internal gene multiplication. Each CEA and NCA has hydrophobic domain in the C-terminus consisting of 26 amino acids which is eliminated when it binds with membrane and is reconstituted by combining with phosphatidylinositol glycan, whereas BGPI contains transmembrane and cytoplasmic domains. It is of interest that CEA and NCA have been found to function as adhesion molecules. The structure and possible function of another CEA gene family, PS beta G, were also introduced in this short review.

Adenoma↗
PubMed1990

[Multilocular cystic renal cell carcinoma: a report of 2 cases].

We report 2 cases of renal cell carcinoma which rarely occur as multilocular cystic masses. By means of echography, both cases were discovered as abnormal shadows occupying the middle portion of the left kidney. Using computerized tomography and selected renal arteriography, we tried to obtain an accurate diagnosis, but few specific malignant findings were gained. Finally, we made the histopathological diagnosis. In addition, we concluded by careful pathological examination that they were multilocular cystic growths. It was difficult to differentiate them preoperatively from multilocular cystic nephroma. Both patients are still alive without tumor recurrence.

Adult↗
PubMed1990

[Assessment of lumbar trabecular bone density by means of single energy quantitative CT in hospital control children and bone metabolic disorders. 1].

We studied the 3rd lumbar vertebral trabecular bone mineral density in 59 cross-sectional pictures of quantitative computed tomography (QCT) with CaCO3 phantom for 28 hospital control children and 30 cases of suspected bone metabolic disorders. The QCT value of bone mineral density of control children showed neither age dependency nor sexual difference before puberty: for males was 221.8 +/- 30.2 mg CaCO3/cm3 (Mean +/- SD) under 4 years, 218.1 +/- 39.7 at 5-9 years and 217.2 +/- 30.9 at 10-15 years; and for females 220.9 +/- 18.3 under 4 years and 240.0 +/- 29.4 at 5-9 years. The QCT values of bone mineral density in bed-ridden patients, children receiving glucocorticoids and children receiving anticonvulsants were significantly lower than that in control children (p less than 0.005). The QCT value of bone mineral density of bed-ridden patients was significantly lower than that of children receiving glucocorticoids and of children receiving anticonvulsants (p less than 0.05, p less than 0.005 respectively). Our study confirmed that single energy quantitative CT was very useful in pediatric clinical application.

Adolescent↗
PubMed1990

Purification of 45 KDa estramustine binding protein (EMBP) and preparation of its antibody.

The purification of 45 KDa EMBP and the production of monospecific anti-serum is described. 45 KDa EMBP was purified by relatively simple methods using ion exchange HPLC (TSK-GEL DEAE-5PW column) and size exclusion HPLC (TSK-GEL G3000SW column). The results clearly demonstrated the speed and simplicity of the method using these columns, compared to previously-described methods for purification of 45 KDa EMBP.

Amino Acids↗
PubMed1990

[Application of polymerase chain reaction for bone marrow transplantation].

Polymerase chain reaction (PCR) is a recently-developed technique capable of amplifying a specific nucleotide sequence and has been proved highly sensitive enough to analyse a small amount of DNA. This prompts us to study minimal residual disease (MRD) which is undetectable by conventional morphological or cytogenetic analysis. Using this technique, tumor specific chimeric DNA or mRNA were detected in patients with follicular lymphoma with t(14; 18) or in Ph1 positive ALL in complete remission, respectively. PCR was also useful to monitor MRD after treatment of bone marrow cells with monoclonal antibody. In sex-mismatched bone marrow transplantation, mixed chimerism was well documented by using repeated sequences which is unique to human Y chromosome. These results suggested that PCR offers a great help for detecting MRD or mixed-chimerism following bone marrow transplantation.

Bone Marrow Transplantation↗
PubMed1989

Immunohistological and immunochemical characterization of a novel pancreatic cancer-associated antigen MUSE11.

Using the ascites fractions of a cancer patient as an immunogen, we have recently prepared an interesting monoclonal antibody (MoAb), MUSE11 (IgG1), to a circulating pancreatic cancer-associated antigen (antigen MUSE11). Immunoperoxidase study revealed that antigen MUSE11 was detected in virtually all adenocarcinomas (especially pancreatic carcinoma), whereas it was either negative or faintly positive in their normal counterparts among the digestive organ tissues. Western blotting analysis and periodic acid-Schiff carbohydrate staining revealed that antigen MUSE11 is a Mr 300,000 glycoprotein that is clearly different from other high-molecular-weight glycoprotein antigens which have been used for detection of circulating antigens in pancreatic cancer patients. MoAb MUSE11 appears to react with a peptide epitope of this molecule, since periodic acid and neuraminidase treatment of the antigen did not affect the reactivity of MoAb MUSE11 with the antigen, but trypsin and protease treatment abolished the reactivity. The antigen MUSE11 was purified using affinity chromatography in conjunction with MoAb MUSE11. This antigen appears to be highly glycosilated with N-linked carbohydrate moieties, since treatment of the pancreatic carcinoma Panc-1 cells with tunicamycin reduced the molecular weight band to Mr 110,000. Once antigen MUSE11 has been purified by affinity chromatography, neither CA19-9 nor pancreatic oncofetal antigens can be detected, although they were present at very high levels in the crude ascitic starting material.

Animals↗
PubMed1989

Ruthenium-iron hybrid hemoglobins as a model for partially liganded hemoglobin: oxygen equilibrium curves and resonance Raman spectra.

The structure and function of iron(II)-ruthenium(II) hybrid hemoglobins alpha(Ru-CO)2 beta(Fe)2 and alpha(Fe)2 beta(Ru-CO)2, which can serve as models for the intermediate species of the oxygenation step in native human adult hemoglobin, were investigated by measuring oxygen equilibrium curves and the Fe(II)-N epsilon (His F8) stretching resonance Raman lines. The oxygen equilibrium properties indicated that these iron-ruthenium hybrid hemoglobins are good models for the half-liganded hemoglobin. The pH dependence of the oxygen binding properties and the resonance Raman line revealed that the quaternary and tertiary structural transition was induced by pH changes. When the pH was lowered, both the iron-ruthenium hybrid hemoglobins exhibited relatively higher cooperativity and a Raman line typical of normal deoxy structure, suggesting that their structure is stabilized at a "T-like" state. However, the oxygen affinity of alpha(Fe)2 beta(Ru-CO)2 was lower than that of alpha(Ru-CO)2 beta(Fe)2, and the transition to the "deoxy-type" Fe-N epsilon stretching Raman line of alpha(Fe2)beta(Ru-CO)2 was completed at pH 7.4, while that of the complementary counterpart still remained in an "oxy-like" state under the same condition. These observations clearly indicate that the beta-liganded hybrid has more "T"-state character than the alpha-liganded hybrid. In other words, the ligation to the alpha subunit induces more pronounced changes in the structure and function in Hb than the ligation to the beta subunit. This feature agrees with our previous observations by NMR and sulfhydryl reactivity experiments. The present results are discussed in relation to the molecular mechanism of the cooperative stepwise oxygenation in native human adult hemoglobin.

Chemical Phenomena↗
PubMed1989

NMR study of human mutant hemoglobins synthesized in Escherichia coli. Consequences of tyrosine alpha 42 substitutions.

The hydroxyl group of Tyr alpha 42 in human hemoglobin forms a hydrogen bond with the carboxylate of Asp beta 99 which is considered to be one of the most important hydrogen bonds for stabilizing the "T-state." However, no spontaneous mutation at position 42 of the alpha subunit has been reported, and the role of the tyrosine has not been tested experimentally. Two artificial human mutant hemoglobins in which Tyr alpha 42 was replaced by phenylalanine or histidine were synthesized in Escherichia coli, and their proton NMR spectra were studied with particular attention to the hyperfine-shifted and hydrogen-bonded proton resonances. The site-directed mutagenesis of the Tyr alpha 42----Phe removes the hydrogen bond described above and prevents transition to the T-state so that the mutant Hb is rather similar to the "R-state" even when deoxygenated. On the other hand, the mutation from tyrosine to histidine causes less drastic structural changes, and its quaternary and tertiary structures are almost the same as native deoxy-Hb A. This may be attributed to the formation of a new hydrogen bond between His alpha 1(42) and Asp beta 2(99). These observations indicate that the hydrogen bond formed between Tyr alpha 42 and Asp beta 99 is required to convert unliganded Hb to the T-state.

Escherichia coli↗
PubMed1989

Determination of dopamine, norepinephrine, and related trace amines by prechromatographic derivatization with naphthalene-2,3-dicarboxaldehyde.

Dopamine, norepinephrine, octopamine, tyramine, and 3,4-dihydroxybenzylamine react readily with naphthalene-2,3-dicarboxaldehyde in the presence of cyanide ion under mild conditions to give highly fluorescent cyanobenz[f]isoindole (CBI) products. The CBI products exhibit good solution chemical stability. The high-fluorescence quantum efficiency of the CBI fluorophore and the ability to excite these adducts in the visible region (420-450 nm) enhance the sensitivity and selectivity of this derivatization detection technique. The CBI products of catecholamines and "trace" amines are readily separated by reverse-phase HPLC giving detection limits in the 20 to 60 fmol range (S/N = 3). A prechromatographic derivatization HPLC assay for the trace analysis of dopamine and norepinephrine in urine is described.

Biogenic Amines↗
PubMed1989

[Combination therapy of renal cell carcinoma with interferon-alpha and UFT (or FT-207)].

Human lymphoblastoid interferon (IFN-alpha MOR-22; OIF) was administered to forty-two patients suffering from renal cell carcinoma. Twenty-six patients with metastatic lesions or primary tumor were treated in a clinical trial with either MOR-22 alone or combination of MOR-22 and UFT (or FT-207). The efficacy was assessed in ten of twenty patients who had received MOR-22 alone for more than eight weeks, but objective response was not observed. The efficacy was done in eight of fourteen patients with MOR-22 and UFT (or FT-207) in combination. Complete response was achieved in one, and partial response in two, with an objective response rate of 37.5%. But the difference was no statistically significant in the survival rate of each therapy. In evaluable twenty patients with MOR-22 prophylactically, there was only one case who had occurred lung metastases with a refractory rate of 8.3%. Forty-one patients were examined for side effects to drugs. The main side effects were fever, anorexia, general fatigue, hematologic toxicities, and hepatic dysfunction in both therapy. These side effects occurred with more increased frequency in combination therapy of UFT (or FT-207) compared to MOR-22 alone.

Adult↗
PubMed1989

Etiohemin as a prosthetic group of myoglobin.

Sperm whale myoglobin was reconstituted with etioheme and the stoichiometric complex formation was confirmed. The proton NMR spectrum of the deoxy myoglobin exhibits an NH signal from the proximal histidine at 78.6 ppm, indicating heme incorporation into the heme pocket to form the Fe-N(His-F8) bond. The appearance of a single set of the heme-methyl NMR signals shows that etioheme without acid side-chains specifically interacts with the surrounding globin. The visible spectral data suggest retention of a normal iron coordination structure. The functional and NMR spectral properties of etioheme myoglobin are similar to those of mesoheme myoglobin, reflecting the absence of the electron-withdrawing heme vinyl groups.

Animals↗
PubMed1989

Structure-function relationships in hemoglobin Kariya, Lys-40(C5) alpha----Glu, with high oxygen affinity. Functional role of the salt bridge between Lys-40 alpha and the beta chain COOH terminus.

The epsilon-amino group of Lys-40 alpha forms a salt bridge with the alpha-carboxyl group of beta chain in deoxyhemoglobin and is considered to impose a constraint upon hemoglobin tetramer, stabilizing the T quaternary structure. Hb Kariya, in which Lys-40 alpha is replaced by Glu, provides a unique opportunity to investigate the functional role of this salt bridge. Hb Kariya showed oxygen binding properties characterized by a high affinity, diminished cooperativity, a reduced alkaline Bohr effect, and a decreased effect of phosphates upon oxygen affinity. In deoxyHb Kariya the reactivity of the sulfhydryl groups of cysteins-93 beta with 4,4'-dipyridine disulfide was profoundly enhanced, being comparable to that for normal oxyhemoglobin (oxyHb A). The Soret band spectra, UV derivative spectra, and UV oxyminus-deoxy difference spectra indicated that oxyHb Kariya assumes a quaternary structure similar to that of oxyHb A whereas the T structure of deoxyHb Kariya is destabilized, and Hb Kariya remains predominantly in the R state upon deoxygenation. Resonance Raman scattering by deoxyHb Kariya showed that the Fe-N epsilon(proximal His) bond is less stretched than that of deoxyHb A. These experimental results provide structural basis for explaining the oxygen binding characteristics of Hb Kariya and further give direct evidence that the intersubunit salt bridge between Lys-40 alpha and the beta chain COOH terminus actually contributes to stabilization of the T quaternary structure, thereby playing a key role in cooperative oxygen binding by hemoglobin. The nature of another salt bridge between Asp-94 beta and the COOH-terminal His of beta chain was also discussed in comparison with the salt bridge involving Lys-40 alpha.

2,3-Diphosphoglycerate↗