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K Mukai

Publications and source records attributed to K Mukai.

At least 19 recordsLinked to original sources
PubMed1992

Stopped-flow kinetic study of vitamin E regeneration reaction with biological hydroquinones (reduced forms of ubiquinone, vitamin K, and tocopherolquinone) in solution.

A kinetic study of the regeneration reaction of vitamin E (tocopherol) with eight biological hydroquinones (HQs) (ubiquinol-10 (Q10H2 1); ubiquinol-0 (Q0H2 2); vitamin K1 HQ (VK1H2 3); vitamin K3 HQ (VK3H2 4); alpha-, beta-, and gamma-tocopherol-HQs (alpha-, beta-, and gamma-TQH2 5-7); and 2,3,5-trimethyl-1,4-HQ (TMQH2 8)) in solution was performed. The second-order rate constants (k4) for the reaction of HQs 1-8 with alpha-tocopheroxyl and 5,7-diisopropyltocopheroxyl radicals in ethanol, benzene, and isopropyl alcohol/water (5:1, v/v) solutions were measured with a stopped-flow spectrophotometer. The order of magnitude of k4 values obtained for HQs is VK1H2 > VK3H2 > alpha-TQH2 > beta-TQH2 approximately gamma-TQH2 approximately TMQH2 > Q10H2 > Q0H2, being independent of the kinds of tocopheroxyl radicals and the polarity of the solvents. The log of the k4 values obtained for HQs was found to correlate with their peak oxidation potentials. Comparing the k2 value (2.68 x 10(6) M-1 s-1 obtained for the reaction of alpha-tocopheroxyl with vitamin C (sodium ascorbate) with those (k4 = 2.54 x 10(5) and 8.15 x 10(5) M-1 s-1) obtained for the reaction of alpha-tocopheroxyl with Q10H2 and alpha-TQH2 in isopropyl alcohol/water mixtures, the former is approximately 11 and 3 times as reactive as the latter, respectively. On the other hand, the k2 value obtained for sodium ascorbate is smaller than the k4 values obtained for VK1H2 and VK3H2. These results suggest that mixtures of vitamin E and these HQs (as well as those of vitamins E and C) may function synergistically as antioxidants in various tissues and mitochondria.

Ascorbic Acid↗
PubMed1992

Vitamin E: inhibition of retinol-induced hemolysis and membrane-stabilizing behavior.

For the elucidation of the mechanism of membrane stabilization by vitamin E, the effects of alpha-tocopherol and its model compounds on either retinol-induced hemolysis of rabbit erythrocytes or the permeability and fluidity of liposomal membranes have been studied. Retinol-induced rabbit erythrocyte hemolysis has been found not to be caused by the oxidative disruption of erythrocyte membrane lipids initiated by retinol oxidation, but rather to arise from physical damage of the membrane micelle induced by penetration of retinol molecules. In suppressing hemolysis, alpha-tocopherol was more effective than other naturally occurring tocopherols. alpha-Tocopheryl acetate, nicotinate, and 6-deoxy-alpha-tocopherol were more effective than alpha-tocopherol itself. The inhibitory effects of alpha-tocopherol model compounds having side chains with at least two isoprene units or a long straight chain instead of the isoprenoid side chain were similar to those of alpha-tocopherol. These data suggest that for protection of membranes against retinol-induced damage, the hydroxyl group of alpha-tocopherol is not critical, but rather the chroman ring, three methyl groups on the aromatic ring, and the long side chain are necessary. To verify the mechanism of the inhibitory effect on hemolysis, not only the effect of vitamin E and its model compounds on the membrane permeability and fluidity, but also the mobility of alpha-tocopherol molecule in membranes has been investigated using bilayer liposomes as the model membranes. Addition of alpha-tocopherol to membranes produced a greater decrease in the permeability and fluidity of rat liver phosphatidylcholine liposomes compared with egg yolk phosphatidylcholine liposomes. In dipalmitoylphosphatidylcholine liposomes, however, alpha-tocopherol was less effective, that is, the more unsaturated the lipids, the more they interact with alpha-tocopherol. 2,2,5,7,8-Pentamethyl-6-chromanol with no isoprenoid side chain and phytol without the chromanol moiety had no effect. The measurement of 13C NMR relaxation times revealed that the mobility of methyl groups on the aromatic ring of alpha-tocopherol in membranes is significantly restricted. In contrast, the methyl groups at positions 4'a and 8'a on the isoprenoid side chain have high degrees of motional freedom in the lipid core of membranes. Furthermore, it was found that alpha-tocopherol in membranes interacts with chromate ions added as potassium chromate outside the membranes, resulting in an increase in membrane fluidity. These results are compatible with those of the inhibitory effect on retinol-induced erythrocyte hemolysis. On the basis of the results obtained here, a possible mechanism for membrane stabilization by vitamin E is proposed.

Animals↗
PubMed1992

Proliferative activity of cutaneous melanocytic neoplasms defined by a proliferating cell nuclear antigen labelling index.

To evaluate the proliferative activity of benign, borderline and malignant cutaneous melanocytic neoplasms, 30 cases of malignant melanoma (MM) and 41 cases of naevi were studied by immunostaining using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). PCNA is a nuclear antigen expressed in the late G1 and S phase and serves as a marker of proliferating cells. Invasive MM and MM in situ showed much higher PCNA positivity rates than melanocytic naevi (invasive MM, 18.0%; MM in situ, 11.3%; ordinary melanocytic naevi, 2.6%). The PCNA positivity rate did not increase significantly with the thickness of MM. Among ordinary melanocytic naevi, junctional naevi had a higher PCNA positivity rate than compound or intradermal naevi. Mean PCNA positivity rates for Spitz's naevi and sporadic dysplastic naevi were within the range for ordinary melanocytic naevi, indicating the benign nature of both types of naevus. Contrary to some previous studies, MM in situ showed high proliferative activity, indicating that cells of MM in situ are actively proliferating. This study clearly demonstrates that MM and various types of naevi can be separated according to differences in proliferative activity defined by the PCNA labeling index.

Antibodies, Monoclonal↗
PubMed1992

Extracellular poly(hydroxyalkanoate) depolymerases and their inhibitor from Pseudomonas lemoignei.

Enzymatic degradation processes of microbial copolyesters, poly(3-hydroxybutyrate-co-3-hydroxyvalerate): P(3HB-co-3HV) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate): P(3HB-co-4HB), were studied by the weight loss (erosion) of copolyester films. These studies employed three extracellular depolymerases which degrade poly(3-hydroxybutyrate): P(3HB). Two enzymes were purified from the culture supernatant of Pseudomonas lemoignei and one from Alcaligenes faecalis T1. The rate of enzymatic degradation of microbial copolyester films with various compositions showed an almost similar tendency to three different P(3HB) depolymerases, and decreased in the following order: P(3HB-co-4HB) greater than P(3HB) greater than P(3HB-co-3HV). An inhibitory protein of P(3HB) depolymerases in the succinate culture medium of P. lemoignei was isolated and characterized. The molecular weight of P(3HB) depolymerase inhibitor was 35,000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. This inhibitor of a single polypeptide chain may reversibly bind the serine residues at the active site of P(3HB) depolymerase. This inhibitory protein was not induced in the culture medium when P. lemoignei was grown on P(3HB) as the sole carbon source.

Carboxylic Ester Hydrolases↗
PubMed1992

Detection of Epstein-Barr virus DNA in a Japanese case of lymphoepithelioma-like thymic carcinoma.

Epstein-Barr virus DNA was detected in a case of lymphoepithelioma-like thymic carcinoma. A homogeneous terminal structure of the viral DNA was demonstrated in this case, indicating the presence of the viral genome in clonally expanded tumor cells. Since all of 26 other thymic epithelial tumors (eight non-invasive, 13 invasive thymomas and four non-lymphoepithelioma-like thymic carcinomas) in Japanese were negative by polymerase chain reaction, it is suggested that lymphoepithelioma-like thymic carcinoma may represent a unique pathological entity distinct from Epstein-Barr virus-negative thymic epithelial tumors, which are in the majority in Japan.

Carcinoma, Squamous Cell↗
PubMed1992

Sebaceous gland and sweat gland carcinomas of the skin. Clinicopathological study and significance of c-erbB-2 oncoprotein expression.

Thirteen sebaceous gland carcinomas and 10 sweat gland carcinomas were examined to elucidate any important histological parameters influencing their prognosis, and the relationship between immunohistochemical expressions of c-erbB-2 oncoprotein and survival of the patients was analyzed. Sebaceous gland carcinomas with vacuolated cytoplasm in more than 50% of whole tumor area, with necrosis, and without lymphoid cell infiltration in tumor nests and stroma had a higher incidence of tumor recurrence and tumor-related death than tumors with vacuolated cytoplasm in 50% or less of whole tumor area (p < 0.01), without necrosis, and with lymphoid cell infiltration in tumor nest and stroma (p < 0.05). Sweat gland carcinomas of all cases with fatal outcomes demonstrated tubular differentiation in 20% or less of whole tumor area, lymphatic permeation and desmoplastic reaction. Three sebaceous gland carcinomas and three sweat gland carcinomas were positive for c-erbB-2 oncoprotein. Two of three sebaceous gland carcinomas, and all three sweat gland carcinomas developed tumor recurrence and ended in tumor-related deaths. Sweat gland carcinomas with c-erbB-2 expression had significantly shorter survival than those with negative immunostain (p < 0.01). Cytoplasmic appearance, tumor necrosis, and lymphoid cell infiltration in tumor nests and stroma of sebaceous gland carcinoma, and tubular differentiation, lymphatic permeation, and growth patterns of sweat gland carcinoma are considered to closely correlate to the prognosis. Immunohistochemically detected c-erbB-2 oncoprotein may be an indicator of bad prognosis.

Adolescent↗
PubMed1992

Stabilization of phosphorylated Bacillus subtilis DegU by DegR.

The production of Bacillus subtilis extracellular proteases is under positive and negative regulation. The functional role of degR, one of the positive regulators, was studied in relation to the degS and degU gene products, which belong to the bacterial two-component regulatory system. Studies with a translational fusion between the Escherichia coli lacZ and the Bacillus subtilis subtilisin (aprE) genes indicated that the stimulatory site of DegR lay upstream of position -140, with the region upstream of position -200 being the major target. It was also found that degS and degU were epistatic to degR. These results suggested some relationship among the degR, degS, and degU gene products. The DegR protein was purified to homogeneity, and its in vitro effect on the phosphorylation reaction involving DegS and DegU was studied. For this purpose, a soluble-extract system in which the formation and dephosphorylation of DegU-phosphate could be examined was devised. The addition of DegR to the soluble-extract system enhanced the formation of DegU-phosphate. The enhancing effect was found to be due to the protection of DegU-phosphate from dephosphorylation. From these results, it was concluded that the positive effect of DegR on the production of the extracellular proteases is brought about by the stabilization of DegU-phosphate, which in turn may result in the stimulation of transcription of the exoprotease genes.

Bacillus subtilis↗
PubMed1992

Immunohistochemical study of c-erbB-2 oncoprotein overexpression in human major salivary gland carcinoma: an indicator of aggressiveness.

In order to analyze the correlation between immunohistochemical positivity for c-erbB-2 oncoprotein and prognosis in patients with malignant salivary gland tumors, 59 cases of malignant tumors of the major salivary glands, including 35 parotid gland, 20 submaxillary gland and 4 sublingual gland tumors, were studied immunohistochemically using a polyclonal antibody against c-erbB-2 oncoprotein. Positive staining was observed in 13 (22%) of the 59 cases. Interestingly, positive results were obtained only in adenocarcinoma (6/20) and carcinoma in pleomorphic adenoma (7/15), and not in any other histological types such as adenoid cystic carcinoma, mucoepidermoid tumor, and squamous cell carcinoma. There was no correlation between the degree of differentiation of adenocarcinoma and c-erbB-2 positivity. Since the carcinoma in pleomorphic adenoma positive for c-erbB-2 oncoprotein was adenocarcinoma, adenocarcinoma and adenocarcinoma in pleomorphic adenoma were placed together (n = 33), and the presence or absence of c-erbB-2 oncoprotein in this group was examined for correlation with patients' survival and other clinicopathological features, including clinical stage, tumor size, surgical margins, and lymph node status. The c-erbB-2-positive tumors tended to be more advanced and larger than negative tumors. Similarly, c-erbB-2-positive tumors were difficult to resect completely, were associated with lymph node metastasis more frequently, and showed lower disease-free survival than negative cases (P less than .05). We conclude that immunohistochemical positivity for c-erbB-2 is an indicator of aggressiveness in both adenocarcinoma and adenocarcinoma in pleomorphic adenoma of the major salivary glands.

Adenocarcinoma↗
PubMed1992

Experience and present status of telepathology in the National Cancer Center Hospital, Tokyo.

The optical fiber high definition television (HDTV) live image system with a remote control microscope is an ideal telepathology system. Diagnostic accuracy with this system is high enough for pathology consultation. However, it is very expensive to set up. The integrated services digital network (ISDN)-HDTV still image system using public telephone lines presently available in Japan INS 64 (64 kb/s), is not suitable for frozen section diagnosis and diagnosing difficult lesions. However, it functions very well for cytology consultation. When INS 1500 (1.5 Mb/s) becomes available in practice, it can substitute the optical fiber-HDTV live image system in terms of cost and efficacy. Pathologists must become accustomed to making diagnosis from images on the monitor. They must be very careful in making diagnosis, when images are transmitted from institutions without pathologists, since selection error may occur at the time of frozen section and at the time of transmission of images.

Cancer Care Facilities↗
PubMed1992

Intracellular distribution of CPT-11 in CPT-11-resistant cells with confocal laser scanning microscopy.

CPT-11, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy camptothecin, is a well-known DNA topoisomerase I inhibitor. SN-38 is a metabolite of this compound. Both emit fluorescence when activated by a laser beam. With a confocal laser scanning microscope (CLSM), we determined the intracellular distribution of CPT-11 and SN-38 and the chronological changes in drug-treated PC-7, a cell line of human non-small cell lung cancer, and its CPT-11 resistant variant, PC-7/CPT cells. There were many more granules in the cytoplasm in PC-7/CPT than in the parent cell line (PC-7). The granule formation of the resistant cell could indicate a different drug metabolism in the cytoplasm from that of the parent cell. This technique would provide a new way of investigating the mechanism of resistance of cancer cells to anticancer drugs.

Antineoplastic Agents, Phytogenic↗
PubMed1992

The AMeX method: a multipurpose tissue-processing and paraffin-embedding method. Extraction of protein and application to immunoblotting.

The authors have previously reported a new fixation and paraffin-embedding method (the AMeX method), which preserves many antigens as well as high molecular-weight DNA and RNA that are normally destroyed by the routine formalin fixation and paraffin-embedding process. In the present study, the authors analyzed the preservation of protein suitable for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting in tissue fixed by the AMeX method. The method used for extraction of protein from AMeX-processed tissue sections after deparaffinization was the same as that for extraction from fresh tissues. The total amount of protein extracted from 50-mg (wet weight) AMeX-processed mouse liver tissue was the same as that from fresh tissue. The electrophoretic mobility and staining intensity of protein on SDS-polyacrylamide gel, and the immunoblotting pattern and staining intensity with several antibodies, were identical for both AMeX-processed and fresh tissue. Degradation of protein was minimal for storage periods of 2 years in paraffin block. The authors also showed that pellets of cultured cells can be processed by this method for immunologic analysis. This new fixation and paraffin-embedding method is a useful tool for obtaining information on correlations between morphologic features and immunochemical and molecular biological data.

Animals↗
PubMed1992

Signet-ring cell carcinoid: a primary hepatic carcinoid tumor with cytoplasmic inclusions comprising of aggregates of keratin.

A case of primary hepatic carcinoid tumor was recently encountered, which was argyrophil and showed positive reactions to serotonin, gastrin and pancreatic peptide in an immunohistochemical hormonal study. The tumor had unusual morphologic features. The neoplastic cells had a signet-ring cell appearance, similar to the signet-ring cells normally seen in mucin-producing adenocarcinoma. Ultrastructural and immunohistochemical studies revealed the formation of the signet-ring cells to have been caused by the presence of cytoplasmic inclusions consisting of cytokeratins. Further investigation, using eight monoclonal antibodies recognizing cytokeratins of different molecular weights, showed the accumulated cytokeratins to be of low and medium molecular weights. The morphologic observations in this unusual case of hepatic carcinoid tumor are described and reported cases with similar features, for which we propose the term "signet-ring cell carcinoid," are reviewed.

Adult↗
PubMed1992

[Right coronary spasm immediately after coronary artery bypass grafting for the left coronary artery].

Right coronary spasm immediately after coronary artery bypass grafting for the left coronary artery in a 39-year-old male is described. After the patient was returned to ICU, ECG at leads II, III, and aVF changed suddenly, ventricular tachycardia (right ventricle origin) and cardiac arrest ensured. As neither administration of drug nor application of D.C. was effective. The chest was reopened at ICU. Though there was sufficient flow in the left coronary artery bypass graft flow, the right ventricle did not constrict at all. Right coronary artery spasm was diagnosed, and, upon application of the direct cardiac massage and D.C. at the cardiac surface, cardiac rhythm and blood pressure were normalized. IABP was inserted to improve cardiac function, and the chest was closed. In addition, nitroglycerin and diltiazem were infused continuously. No spasm has occurred after this episode, and the patient has been discharged and is doing well.

Adult↗
PubMed1992

Surgical management of biliary cystadenocarcinoma.

Four patients, one woman and three men, with biliary cystadenocarcinoma were surgically treated during a 7-year period. The mean age was 58 years. Symptoms prior to admission were mild, and blood tests including liver function tests, CEA and AFP were for the most part within the normal range. Surgery followed diagnostic work-up including US, ERCP, CT, angiography and MRI. Radical surgery was accomplished in three patients by extended left lobectomy in two and extended right lobectomy in one patient, respectively, in this latter patient preceded by therapeutic embolization of the right portal branch prior to resection, while the fourth patient had a palliative resection. Histological examination revealed papillary adenocarcinoma with mucin production within the cyst. The size of the cyst (maximum diameter) varied between 4.5 and 24 (mean 12) cm. The postoperative course was uneventful in all patients. Two patients are alive with no sign of recurrence 5 and 53 months after surgery, while two patients died after 26 and 75 months, respectively. Thus, radical resection of this rare kind of malignant hepatic tumor seems to offer a chance of long-time survival.

Aged↗
PubMed1992

[Basic study of myocardial coagulation by intraoperative laser ablation: in the presence and absence of blood].

To investigate whether the efficacy of laser ablation therapy is affected by the color of the target organ, we irradiated 9 canine hearts through the epicardium with Nd-YAG laser (200 J, 400 J), and compared coagulated myocardial volume in the beating heart (reddish) with that in the stopped heart (whitish) infused with 0 degrees C saline (cardioplegic model) via a coronary artery. The coagulated myocardial volume of the beating heart was significantly larger than that of the arrested heart, indicating the YAG laser energy is absorbed by red myocardium to greater extent than it is by white myocardium. In conclusion, during intraoperative laser ablation, the presence or absence of blood in cardiac tissue is an important factor for safe irradiation.

Animals↗
PubMed1992

[A successful emergency surgical treatment of DeBakey type I dissecting aneurysm complicated with cardiac tamponade and bleeding shock].

A successful emergency replacement of the ruptured ascending thoracic aorta by means of ringed Dacron tube graft for 69-year-old male was presented, who had been admitted to our hospital with deep cyanosis and shock. He had experienced severe chest pain one hour prior to admission followed by mental confusion and was brought by ambulant service. Emergency chest enhanced computed tomography showed a clear ruptured dissecting aneurysm (DeBakey Type I) with complicated with pericardial tamponade. Soon after this admission he developed bradycardia with hypotension and quickly went into shock. After induction of anesthesia, cardiac arrest developed. External cardiac massage was started at the same time. Partial cardiopulmonary bypass using femoral vein to artery bypass with the membrane oxygenator was instituted and the body was cooled until moderate hypothermia (25 degrees C). The pericardium was opened and blood clot was removed. The ascending aorta ruptured which was replaced with ringed Dacron tube graft (24 mm in diameter). Patient tolerated procedure well and made good postoperative recovery with temporally mild mental confusion. He discharged 2 months after the surgery without any neurological or mental complication. He has been followed up for six months in excellent condition.

Aged↗