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M Endo

Publications and source records attributed to M Endo.

At least 19 recordsLinked to original sources
PubMed1992

Calcium-dependent immediate feedback control of inositol 1,4,5-triphosphate-induced Ca2+ release.

The temporal and spatial distribution of increases in intracellular Ca2+ concentration is an important factor in cellular signal transduction. Inositol 1,4,5-trisphosphate (InsP3) plays a key part in agonist-induced Ca2+ release, which can take place abruptly and in a confined space by a mechanism that is not fully understood. Here we analyse the kinetics of InsP3-induced Ca2+ release following flash photolysis of caged InsP3 or caged Ca2+, and demonstrate that Ca(2+)-dependent immediate feedback control is an important determinant of the time course of Ca2+ release. The positive feedback mechanism is also important for the 'loading dependence' of InsP3-induced Ca2+ release. Furthermore, our results support the operation of positive cooperativity in channel opening and feedback control augments the steep InsP3 concentration-Ca2+ release relation. These inherent properties of InsP3-induced Ca2+ release are expected to give rise to temporally abrupt and/or spatially confined Ca2+ release within the cell.

Animals↗
PubMed1992

A new endo-beta-galactosidase acting on the Gal beta 1-3Gal linkage of the proteoglycan linkage region.

A new type of endo-beta-galactosidase acting on the linkage region of peptidochondroitin sulfate was isolated from the mid-gut gland of the mollusk Patinopecten. The purification procedure included ammonium sulfate precipitation, Sephacryl S-200HR gel filtration, DEAE-Sephacel chromatography, and TSKgel Phenyl-5PW RP high performance liquid chromatography. The purified enzyme was free from exoglycosidases, sulfatases, and phosphatases. The specificity of the enzyme was as follows. 1) It acted on the internal galactoside linkage of sugar chains; 2) it specifically hydrolyzed the galactosylgalactose (Gal beta 1-3Gal) linkage, but not the galactosylxylose (Gal beta 1-4Xyl) linkage in the linkage region of peptidoglycans; 3) the enzyme activity was unaffected by the type of glycosaminoglycan, chondroitin sulfate, dermatan sulfate or heparan sulfate used as a substrate; 4) keratan sulfate and some oligosaccharides from glycolipid were not degraded by the enzyme. These properties of the endo-beta-galactosidase characterize it as a new endo-beta-galactosidase with unique specificity.

Animals↗
PubMed1992

Enhancement of Ca2+-induced Ca2+ release in calpain treated rabbit skinned muscle fibers.

Calpain treatment of rabbit skinned muscle fibers resulted in proteolysis of junctional foot protein or Ca2+ release channel of the sarcoplasmic reticulum. Electrophoretic and immunoblot analyses indicate that calpain cleaves off approximately 130 kDa peptide from the N-terminus. After such treatment, Ca2+ capacity of the sarcoplasmic reticulum remained normal and both Ca2+ and adenine nucleotide dependence of Ca2+-induced Ca2+ release mechanism were retained. However, the Ca2+-activated Ca2+ release rate was increased by two fold after the proteolysis. The results suggest the presence of functional domains in the junctional foot protein, and the N-terminus domain controls the activity of the Ca2+ channel without changing Ca2+ and nucleotide sensitivities.

Animals↗
PubMed1992

Hyaluronate synthesized by cultured skin fibroblasts derived from patients with Werner's syndrome.

Hyaluronate in cultured skin fibroblasts derived from patients with Werner's syndrome, who excrete large amounts of urinary hyaluronate, was investigated. The amount of hyaluronate secreted into the medium by Werner's fibroblasts was 2-3-times that of normal fibroblasts, whereas no difference in enzyme activities related to the degradation of hyaluronate was found. Werner's fibroblasts were then cultured in the presence of [3H]glucosamine, and the amount of [3H]hyaluronate and its chain lengths in the medium and matrix (trypsinate) fractions were compared with those of normal cells. No significant difference in the chain length of hyaluronate was observed between normal and Werner's fibroblasts. On the other hand, a significant increase of hyaluronate was found in the matrix fraction of Werner's fibroblasts when the cells reached confluency. In addition, a hyaluronate of small chain length was found in the matrix fraction of Werner's fibroblasts, although this was absent from that of normal cells. It was concluded that the constituents of the extracellular matrix of Werner's fibroblasts differed from those of normal cells, characterized by the presence of a large amount of hyaluronate and a relatively small hyaluronate chain.

Adult↗
PubMed1992

Presence of functionally different compartments of the Ca2+ store in single intestinal smooth muscle cells.

Studies in smooth muscle bundles have shown the presence of functionally different compartments of Ca2+ store, one (S alpha) sensitive to both caffeine and inositol 1,4,5-trisphosphate (IP3), and the other (S beta) sensitive only to IP3. Ca2+ release in isolated single smooth muscle cells from guinea pig taenia caeci was studied to see if both compartments exist within a cell. Responses to caffeine and carbachol were consistently observed but were abolished after treatment with ryanodine, while intracellular application of IP3 induced Ca2+ release after the treatment, albeit smaller in size than control. Thus S alpha and S beta coexist in a single smooth muscle cell and agonist-induced Ca2+ release requires whole store to be loaded with Ca2+.

Animals↗
PubMed1992

Antitumor effect of methionine-depleting total parenteral nutrition with doxorubicin administration on Yoshida sarcoma-bearing rats.

Methionine-depleting total parenteral nutrition (methionine-depleting TPN), which infuses an amino acid solution devoid of L-methionine and L-cysteine as the sole protein source, showed enhancement of the effect of several anti-cancer agents. In this study, the combined effect of the methionine-depleting TPN with the administration of doxorubicin was examined in Yoshida sarcoma (YS)-bearing rats with regard to effects on the primary tumor growth, the extension of metastasis, and the host animal's life span. In the first experiment, immediately after receiving methionine-depleting TPN for 8 days, the animals were killed. Pathologic findings evaluated tumor growth in the implanted site and extension of the metastasis. In the second experiment, the survival period was determined after animals received methionine-depleting TPN for 10 days, with subsequent oral feeding until they died naturally. Proliferation of YS was markedly suppressed. In particular, hematogenous metastasis, which is a characteristic of YS, was suppressed, and a longer survival period (42.7 +/- 15.6 days, mean +/- SD) was attained in rats in the group treated with the methionine-depleting TPN combined with the administration of doxorubicin.

Animals↗
PubMed1992

Elevation of 4 beta-galactosyltransferase activity for paragloboside synthesis in sera of patients with cancer.

Galactosyltransferase activities in sera of cancer patients were determined by assaying the formation of paragloboside from UDP-galactose and lactotriaosylceramide immobilized on microtiter plates by means of the enzyme-linked immunosorbent assay using a monoclonal antibody, H-11, directed to paragloboside. Enzyme properties were as follows. Optimum pH was 6.8 in cacodylate buffer, and Km values were 2 microM for lactotriaosylceramide and 29 microM for UDP-galactose. The enzyme activity was inhibited by the addition of alpha-lactalbumin. Glucose (20 mM) inhibited the enzyme activity in the presence of alpha-lactalbumin (0.1 mg/ml) but not in its absence. These enzyme properties are similar to those of bovine milk galactosyltransferase, indicating that the enzyme in the sera might be lactose synthetase. The enzyme activities in sera from patients with cancer, patients with benign disease, or a reference sample group were assayed. The activity was below the limit of detection (5.5 pmol/25 microliters serum/2 h) in the reference sample group. Remarkable elevations of the enzyme activity were observed with high incidence in patients with cancer, especially those with blood cancer (100%). A high incidence was observed in the progressive stage, and the enzyme activity was detected at stage 1 in lung, esophagus, stomach, colorectal, and testis cancer. The enzyme activity in sera from patients with benign disease was elevated in 22% of the patients. After effective therapies, the enzyme activity decreased to below the limit of detection. Release of the galactosyltransferase into culture medium of cancer cells could be demonstrated. These observations suggest that the galactosyltransferase is released from cancer tissue into the circulation. The present method for the assay of galactosyltransferase may be useful for the detection of patients with cancer and for monitoring neoplastic recurrence after therapy.

Antibodies, Monoclonal↗
PubMed1992

[Signal contamination problem in three-dimensional localization technique of MR spectroscopy--experiment and an analysis of patient data].

Signal contamination from the surrounding volume was studied using the ISIS sequence, a three-dimensional localization technique. In phantom experiments, contamination decreased with the increase of Tr, regardless of where the contamination originated from. In 52 localized liver spectra with a Tr of 2 sec, PCr contamination was estimated at 3 to 4%, and contamination of ATP signals from the surrounding liver tissue at less than 1%, because of the relatively short T1 of ATP in the liver. In the spectra of brain neoplasms obtained using the simultaneous double-volume selection technique, the PCr ratio in the tumor relative to the control area was high in low grade astrocytoma (0.80, n =8) and low in others (0.45, n = 11). Considering contamination and spectral noise, a PCr ratio of less than 0.4 does not strongly suggest the existence of PCr in tumors. Among 25 cases whose therapeutic processes were monitored by MRS, signal disappearance was observed in two cases in the localized spectra after therapy. In both of them, tumor necrosis was proved pathologically and correlated well with spectroscopic findings. It was found that the ISIS technique suppressed signal contamination to the level of several percents, providing spectra of acceptable quality through localization.

Humans↗
PubMed1992

Evaluation of the measurement of the intraoperative transcutaneous partial pressure of oxygen (PtcO2) as a prognostic indicator in vascular reconstruction.

The intraoperative transcutaneous partial pressure of oxygen (PtcO2) was used to monitor 58 vascular reconstructive surgery procedures in 54 patients. The study comprised three groups: Group A (24 limbs without any ischemic symptoms or signs), Group B (45 limbs with intermittent claudication), and Group C (12 limbs with ischemic rest pain, ulceration, and gangrene). In addition in 31 patients the chest wall was monitored simultaneously as a control. The results showed that the PtcO2 values increased immediately and significantly to varying degrees and at varying speeds after unclamping. The controls had higher values than Group A (P > 0.05), Group B (P < 0.05), and Group C (P < 0.05) patients. Further study showed that there were no significant differences between the maximal values in the limbs with good distal vessel run-off in Groups A, B, and C, and in the controls (P > 0.05). It is thus concluded that effective vascular reconstruction in the limbs is indicated by a rapid and marked increase of both the PtcO2 value and the response value, while with a slow and low increase of the value, early graft failure and poor distal vessel run-off should be suspected. We believe that this monitoring method dynamically reflects the functional state during vascular reconstruction and is clinically valid.

Adult↗
PubMed1992

Ion-spray mass spectrometric analysis of glycosaminoglycan oligosaccharides.

Oligosaccharides from hyaluronic acid and chondroitin 6-sulfate were prepared by digestion with testicular hyaluronidase and separated according to their degree of polymerization by gel-permeation chromatography. These materials were successively analyzed by negative-mode ion-spray mass spectrometry with an atmospheric-pressure ion source. An ion-spray interface was used to produce ions via the ion evaporation process, producing mass spectra containing a series of molecular species carrying multiple charges. Using two adjacent multiply charged molecular ions, the exact molecular weights up to the tetradecasaccharide were calculated with a precision of +/- 1 dalton. This type of mass spectrometry was also demonstrated to be feasible for the analysis of mixtures of oligosaccharides, including tetra-, hexa-, octa- and decasaccharides, from hyaluronic acid or chondroitin 6-sulfate without separation. Ion-spray mass spectrometry was thus shown to be applicable to the structural analysis of oligosaccharides from glycosaminoglycans.

Animals↗
PubMed1992

An anatomical study of a new method for enlargement of narrowed aortic annulus: intra-arterial aorto-infundibuloplasty.

A new procedure "intraarterial aorto-infundibuloplasty" for the narrowed aortic annulus is described. Aortic valve replacement is performed through an aorto-pulmonary and infundibular septal incision which is eventually enlarged by a single patch, i.e., a two-dimensional patch instead of a three-dimensional patch as in Konno's procedure. An anatomical study showed that a prosthetic valve three sizes larger than the natural annular diameter could be implanted and the natural annular diameter was increased by as much as 42%.

Animals↗
PubMed1992

A case of popliteal cystic degeneration with pathological considerations.

Adventitial cystic degeneration of the popliteal artery is seldom encountered; only 39 cases have been reported up to now in Japan. The pathogenesis of this disease remains controversial, and the authors describe a case in which the pathological findings differed from cases reported in the previous literature. The subject was a 74-year-old man admitted to our hospital complaining of intermittent claudication. The characteristic findings of cystic degeneration of the popliteal artery were uncovered by contrast-enhanced computed tomography (CT) and duplex sonography. The contrast-enhanced CT showed a low-density area and duplex sonography revealed a multi-lobulated low-echoic lesion. The Doppler signal of the low-echoic lesion could not be detected. While some cysts were found in the adventitia, they were mainly located in the media. The media also showed a remarkable decrease of smooth muscle cells and a prominent mucinous degeneration that had occurred circumferentially. These findings suggest that the medial degeneration noted had occurred prior to cystic formation. Because of this and other findings, we recommend the use of the term cystic degeneration of the popliteal artery in addition to the term cystic adventitial disease of the popliteal artery.

Aged↗
PubMed1992

Role of wrapping in concomitant intra-abdominal aneurysm and colorectal carcinoma. Report of three cases.

The therapeutic measure against concomitant intraabdominal aneurysm and colorectal carcinoma is still a dilemma. Here we report the clinical courses of three cases of colorectal carcinoma coincidental with moderate-sized abdominal aortic or iliac artery aneurysm in those who underwent operations during a recent three-year period. Resection of malignant lesion and wrapping of aneurysm were carried out in all three patients simultaneously. Carcinoma was staged by Dukes classification as A in one patient and B in two patients. All tolerated surgery well without any signs of complications. Two-year or three-year follow-up shows that they have continued to do well, with no further symptoms of abdominal aortic aneurysm, peripheral vascular disease, or recurrence of colorectal carcinoma. We conclude that, if the aneurysm is not about to rupture and the carcinoma is in an advanced stage, then the carcinoma should be resected, associated with interim aneurysmal wrapping. However, both lesions need to be resected eventually for long-term survival.

Aortic Aneurysm, Abdominal↗
PubMed1992

Perfusion of dominant left subclavian artery during thoracic aortic aneurysm operation.

A case of aneurysm of the descending thoracic aorta with dominant left vertebral artery and poor cross-collateral circulation is reported. We believe that in such a patient perfusion of the dominant left subclavian artery is a safe method to prevent vertebrobasilar ischemia during thoracic aortic aneurysm operation under normothermia.

Aorta, Thoracic↗
PubMed1992

Mutations in c-K-ras 2 gene codon 12 during colorectal tumorigenesis in familial adenomatous polyposis.

Colorectal carcinomas may be induced from adenomas, or they may occur de novo. To clarify the histogenesis of colorectal carcinomas, point mutations in codon 12 of the c-K-ras 2 gene in neoplasias of familial adenomatous polyposis patients were examined. Nineteen colorectal advanced carcinomas, 135 adenomatous polyps, 9 hyperplastic polyps, and 27 normal colonic mucosae were obtained from 48 patients. In 27 normal mucosae and 9 hyperplastic polyps, a mutation in the K-ras gene was not detected. Mutations were detected as follows: 0 of 24 in adenomas with mild atypia, 10 of 77 in adenomas with moderate atypia, and 24 of 34 in adenomas with severe atypia. The incidence of mutations in c-K-ras 2 codon 12 is correlated with the degree of atypia of adenomas. However, only 5 such mutations were detected in 19 advanced carcinomas, indicating that the mutation frequency in advanced carcinomas is much lower than that in adenomas with severe atypia. If a mutation of c-K-ras 2 gene is an important component in the formation of adenocarcinoma, these results did not confirm the successive development from adenomas with severe atypia to advanced carcinomas as the main route for colorectal carcinogenesis in familial adenomatous polyposis patients.

Adenomatous Polyposis Coli↗
PubMed1992

Towards an exemplar model of face processing: the effects of race and distinctiveness.

Valentine (1991a, 1991b) described a theoretical framework for face recognition in which faces are encoded as locations in a multidimensional space. It was argued that this approach could provide a unified account of the effects of distinctiveness, inversion, and race on face recognition. In this paper we evaluate the ability of this theoretical framework to account for the effects of distinctiveness and race in four experiments in which white British and Japanese faces served as stimuli and both white British and Japanese students acted as subjects. In a recognition memory experiment the expected "own-race bias" was observed as a Race of Subject x Race of Face interaction. Distinctive faces were recognized more accurately than typical faces, but the effect of distinctiveness did not interact with the race of face or the race of subject. Typical faces were classified faster than distinctive faces in a task in which intact faces had to be distinguished from jumbled faces, as found in earlier work, and the effect of distinctiveness did not interact with the race of face or race of subject. In contrast, a task in which subjects classified faces according to their race did show a greater effect of distinctiveness for own-race faces. The results are discussed in relation to the two specific models within the multidimensional space framework identified by Valentine (1991a): a purely exemplar-based model and a norm-based coding model. It is argued that these results are more easily accommodated in terms of a purely exemplar-based model. Some conceptual problems in applying the norm-based coding model to the effect of race are discussed.

Adult↗
PubMed1992

Tetralogy of Fallot with anomalous origin of left pulmonary artery.

Between 1971 and 1990, 7 patients of tetralogy of Fallot with anomalous origin of left pulmonary artery underwent intracardiac repairs at Tohoku University Hospital. They were 2 males and 5 females with ages ranging from 4 to 26 years old. The right pulmonary artery connected to right ventricle in all cases, whereas no communications between right ventricle and the left pulmonary artery were found. The left pulmonary artery directly originated from the ascending aorta in 2 patients (group I) and connected to the ductus arteriosus in 5 patients (group II and III). In 2 patients (group II), the left pulmonary artery was separated from the pulmonary arterial trunk by the intraluminal membrane, receiving blood supply through the ductus. In the remaining 3 patients (group III), there were no continuations between both pulmonary arteries. At the correction, communication between the left pulmonary artery and the pulmonary arterial trunk could be reconstructed in groups I and II. However, it was not possible in group III, because the ductus arteriosus and the left pulmonary artery had already been occluded before the intracardiac repair. In group III, ventricular septal defect was closed using a one-way valved patch or a perforated patch to decrease supersystemic right ventricular pressure. Postoperative right ventricular aortic pressure ratio was between 0.5 and 0.8 in groups I and II, and between 0.8 and 1.0 in group III. Three patients (one in each group) died after the operation. Severe pulmonary vascular obstructive disease was found in the left lung of group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗