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Biomedical subjects

Y Moriyama

Publications and source records attributed to Y Moriyama.

At least 235 records · Page 13Linked to original sources
PubMed1995

[Management of patients with closing aortic dissection].

Acute aortic dissection is a catastrophic event requiring immediate diagnosis and definitive treatment, while the clinical characteristics of closing aortic dissection are not well known. From Jan. 1991 through Dec. 1994 a total of 24 patients with closing aortic dissection (CAD) was managed at our institution. There were 19 men and 5 women, ranging in age from 49 to 74 years with a mean of 65 years. All patients presented with a sudden onset of severe chest and back pain. Twenty patients had a history of hypertension with a wide mediastinal silhouette on chest X-ray. The diagnosis of CAD was established by contrast computed tomographic (CT) scans in all patients with no evidence of patent false lumen. The descending thoracic aorta was involved in 17 patients and the ascending in 5. Conservative medical management was initially attempted for all. Seven patients (Stanford type A/B: 2/5) ultimately required surgical intervention, and 2 patients died. The follow-up was 100% complete with a mean term of 14.6 months. The overall survival rate was 74% at 3 years after the initial presentation. Based on our clinical experience, all patients with CAD need careful antihypertensive therapy and frequent follow-up studies to assess the aorta.

Aged↗
PubMed1994

Immunological detection of a vacuolar-type H(+)-ATPase in vanadocytes of the ascidian Ascidia sydneiensis samea.

Ascidians belonging to the family Ascidiidae are known to accumulate vanadium from seawater in their blood cells, concentrating vanadium by a factor of 10(7). Among several different types of blood cell, the signet ring cells have both high levels of vanadium and a low pH. These observations suggest the possibility that proton ions concentrated by a H(+)-ATPase are energetically linked to the accumulation of vanadium. In the present experiments, therefore, we made an immunological search for a H(+)-ATPase in the vacuolar membranes of the signet ring cells, as a first step in our attempts to clarify the energetics of the accumulation of vanadium by these cells. Antibodies raised against the 72-kDa and 57-kDa subunits of a vacuolar-type H(+)-ATPase from bovine chromaffin granules reacted with the vacuolar membranes of signet ring cells. Immunoblotting analysis confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies. Furthermore, addition of bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase, inhibited the uptake of protons by the vacuoles of signet ring cells. Thus, the addition of bafilomycin A1 inhibited the pumping function of the vacuoles of signet ring cells, with resultant neutralization of the contents of the vacuoles.

Animals↗
PubMed1994

Association of N-ethylmaleimide-sensitive factor with synaptic vesicles.

N-Ethylmaleimide-sensitive factor (NSF) mediates docking and/or fusion of transport vesicles in the multi-pathways of vesicular transport. NSF was highly expressed in brain and adrenal gland. Immunostaining of cerebellum with an anti-NSF monoclonal antibody showed that NSF is predominantly localized in the molecular layers and the glomeruli of the granule cell layers. This distribution coincided well with that of synaptophysin, a marker protein of synaptic vesicles. Purification and immunoprecipitation revealed that NSF is associated with brain synaptic vesicles. The present results suggest that NSF is associated with synaptic vesicles without Ca2+ influx.

Animals↗
PubMed1994

Expression of vacuolar H(+)-ATPase in osteoclasts and its role in resorption.

By means of light- and electron-microscopic immunocytochemistry, we have demonstrated the expression of vacuolar H(+)-ATPase in mouse osteoclasts. In fully differentiated osteoclasts, intense immunolabeling was observed along the plasma membranes including those of ruffled borders and associated pale vesicles and vacuoles, whereas those of clear zones and basolateral cell surfaces were entirely free of immunoreaction. Specific expression of vacuolar H(+)-ATPase was also detected over polyribosomes and cisterns of the rough-surfaced endoplasmic reticulum. Multinucleated osteoclastic cells were suspended on dentine slices and cultured for 48 h in the presence or absence of either concanamycin B or bafilomycin A1, specific inhibitors of vacuolar H(+)-ATPase. Morphometric analysis of co-cultured dentine slices with backscattered electron microscopy revealed that both inhibitors strongly reduced the formation of resorption lacunae in a dose-dependent manner. These results suggest that vacuolar H(+)-ATPase is produced in the rough-surfaced endoplasmic reticulum, stored in the membrane vesicles, and transported into the ruffled border membranes of osteoclasts, and that this enzyme plays a key role in the creation of an acidic subosteoclastic microenvironment for the demineralization of co-cultured substrates.

Animals↗
PubMed1994

Impalement injury of the thorax: report of a case.

We report herein the case of a 33-year-old man who survived an impalement injury of the thorax involving the heart, esophagus, and spinal cord. The patient was transported to our hospital with the impalement object left in situ and it was extracted under cardiopulmonary bypass in an operating room. The important principles of surgical management contributing to the successful outcome of such patients are discussed following the presentation of this case.

Adult↗
PubMed1994

A review of 103 cases with elective repair for abdominal aortic aneurysm: an analysis of the risk factors based on postoperative complications and long-term follow-up.

From 1982 through 1992, 103 patients (mean age: 69 years) underwent an elective repair of an abdominal aortic aneurysm (AAA) at our institution. One or more postoperative complications occurred in 30 patients (29%), with a mortality rate of 1.9%. Factors which were found to be significantly associated with postoperative complications based on an univariate analysis included male sex (P = 0.0082), operation time (P = 0.0006), the size of the aneurysm (P = 0.0045), the amount of blood loss during operation (P = 0.0037), poor lung function (P = 0.0155), and the platelet count (P = 0.0468). A simple linear regression analysis showed that there were significant correlations among the AAA size, the duration of operation and the amount of blood loss. The age at operation, however, did not influence morbidity or mortality. Complete survival information was obtained in 96 (95%) patients, while the influence of preoperative risk factors on late survival was also examined by the Kaplan-Meier method. The factors influencing long-term survival were determined to be renal dysfunction and age at the time of operation.

Adult↗
PubMed1994

The surgical treatment of 30 patients with cardiac myxomas: a comparison of clinical features according to morphological classification.

Thirty patients with cardiac myxomas whose main clinical symptoms included congestive heart failure, tachyarrhythmia, chest pain and emboli, were successfully treated with surgery. The cardiac myxomas were found in the left atrium in 23 patients, the right atrium in 6, and the right ventricle in 1. Complete follow-up was conducted from 1 month to 15 years (mean 5.4 years) on 28 patients, 24 of whom were in New York Heart Association (NYHA) Class I, and 2 of whom were in NYHA Class II. The actuarial survival rate was 89% 15 years after surgery and no recurrent myxomas have been identified clinically or by echocardiography in any of the patients. Thus, an aggressive surgical approach is recommended prior to the development of heart failure or other complications whenever cardiac tumors are detected.

Adult↗
PubMed1994

Conformational stability of alpha-lactalbumin missing a peptide bond between Asp66 and Pro67.

The peptide bond between Asp66-Pro67 of alpha-lactalbumin was cleaved with formic acid (cleaved alpha-lactalbumin). Secondary structural changes of the cleaved alpha-lactalbumin, in which the two separated polypeptides were joined by disulfide bridges, were examined in solutions of sodium dodecyl sulfate (SDS), urea, and guanidine hydrochloride. The structural changes of the cleaved alpha-lactalbumin were compared with those of the intact protein. The relative proportions of secondary structures were determined by curve fitting of the circular dichroism. The cleaved alpha-lactalbumin contained 29% alpha-helical structure as against 34% for the intact protein. Some helices of the cleaved alpha-lactalbumin which had been disrupted by the cleavage appeared to be reformed upon the addition of SDS of very low concentration (0.5 mM). In the SDS solution, the helicities of both the intact and cleaved proteins increased, attaining 44% at 4 mM SDS. On the other hand, the helical structures of the cleaved alpha-lactalbumin began to be disrupted at low concentrations of guanidine hydrochloride and urea compared with that of the intact protein. However, no difference was observed in the thermal denaturations of the intact and cleaved proteins, except for the difference in the original helicities. The helicities of both proteins decreased with an increase of temperature up to 65 degrees C and recovered upon cooling.

Amino Acid Sequence↗
PubMed1994

ATP-dependent uptake of anti-neoplastic agents by acidic organelles.

Daunomycin, an anti-neoplastic agent, is known to be sequestered by acidic organelles in normal and multidrug-resistant cells [Willingham, M.C., Cornwell, M.M., Cardarelli, C.O., Gottesman, M.M., & Pastan, I. (1986) Cancer Res. 46, 5941-5946]. We studied the mechanism of accumulation of daunomycin into acidic organelles using chromaffin granule vesicles and proteoliposomes reconstituted with purified F-type H(+)-ATPase as model systems. Radiolabeled daunomycin was taken up by chromaffin vesicles upon addition of ATP. Its ATP-dependent uptake was stimulated about 1.4- to 1.8-fold by valinomycin plus K+, but was inhibited by ammonium chloride (10 mM) and nigericin plus K+. Quinidine (5 microM), verapamil (5 microM), or vanadate (0.5 mM), inhibitors of P-glycoprotein, had no effect on its uptake. Daunomycin was also taken up by liposomes reconstituted with F-type H(+)-ATPase. Furthermore, doxorubicin and vinblastine were taken up by these vesicles, whereas colchicine and rhodamine 123 were not. The accumulations of daunomycin and doxorubicin in acidic organelles of cultured cells were decreased by inhibiting vacuolar ATPase by addition of bafilomycin A1 or concanamycin A, or by increasing the internal pH by addition of nigericin. Melittin and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide dissipated the delta pH and inhibited accumulation of daunomycin in the membrane vesicles and acidic organelles in cultured cells. These results indicate that the delta pH established by vacuolar-type ATPase drives the uptake of daunomycin, doxorubicin or vinblastine into acidic organelles, and that no specific transporters are involved in their uptakes.

Adenosine Triphosphate↗
PubMed1994

Characterization of nicotinamide methyltransferase in livers of mice bearing Ehrlich ascites tumors: preferential increase of activity.

There was a 2- to 7-fold increase in nicotinamide methyltransferase activity in the livers of mice and rats bearing seven different kinds of tumors compared with the respective control normal livers, while activity in the tumors themselves was hardly detectable. The activity in the liver started to increase markedly 3-7 days after i.p. transplantation of Ehrlich ascites tumors into the mice, maintaining a plateau up to death. Metabolic conversion of 14C-nicotinamide to 14C-N1-methylnicotinamide was 3-fold higher in the slices of the ascites tumor host liver than in the normal liver, but the conversion to other radioactive metabolites was not significantly different. Nicotinamide methyltransferase was finally purified 20,000-fold with a yield of 4% from the cytosolic fraction of the ascites tumor host liver by means of five purification steps. At every purification step, only one enzyme fraction was detected. The enzyme finally isolated exhibited a single protein band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with a molecular weight of 26,000. As for the compounds investigated, including the substrates for methyltransferases other than nicotinamide methyltransferase, only quinoline could be the substrate for enzyme activity. It is suggested that the increase in enzyme activity in the tumor host liver probably derived from the endogenous enzyme preexisting in the liver before tumor transplantation.

Animals↗
PubMed1994

Genetic cholesteryl ester transfer protein deficiency caused by two prevalent mutations as a major determinant of increased levels of high density lipoprotein cholesterol.

Genetic determinants of HDL cholesterol (HDL-C) levels in the general population are poorly understood. We previously described plasma cholesteryl ester transfer protein (CETP) deficiency due to an intron 14 G(+1)-to-A mutation(Int14 A) in several families with very high HDL-C levels in Japan. Subjects with HDL-C > or = 100 mg/dl (n = 130) were screened by PCR single strand conformational polymorphism analysis of the CETP gene. Two other mutations were identified by DNA sequencing or primer-mediated restriction map modification of PCR products: a novel intron 14 splice donor site mutation caused by a T insertion at position +3 from the exon14/intron14 boundary (Int14 T) and a missense mutation (Asp442 to Gly) within exon 15 (D442G). The Int14 T mutation was only found in one family. However, the D442G and Int14 A mutations were highly prevalent in subjects with HDL-C > or = 60 mg/dl, with combined allele frequencies of 9%, 12%, 21% and 43% for HDL-C 60-79, 80-99, 100-119, and > or = 120 mg/dl, respectively. Furthermore, prevalences of the D442G and Int14 A mutations were extremely high in a general sample of Japanese men (n = 236), with heterozygote frequencies of 7% and 2%, respectively. These two mutations accounted for about 10% of the total variance of HDL-C in this population. The phenotype in a genetic compound heterozygote (Int14 T and Int14 A) was similar to that of Int14 A homozygotes (no detectable CETP and markedly increased HDL-C), indicating that the Int14 T produces a null allele. In four D442G homozygotes, mean HDL-C levels (86 +/- 26 mg/dl) were lower than in Int14 A homozygotes (158 +/- 35 mg/dl), reflecting residual CETP activity in plasma. In 47 D442G heterozygotes, mean HDL-C levels were 91 +/- 23 mg/dl, similar to the level in D442G homozygotes, and significantly greater than mean HDL-C levels in Int14 A heterozygotes (69 +/- 15 mg/dl). Thus, the D442G mutation acts differently to the null mutations with weaker effects on HDL in the homozygous state and stronger effects in the heterozygotes, suggesting dominant expression of a partially defective allele. CETP deficiency, reflecting two prevalent mutations (D442G and Int14 A), is the first example of a genetic deficiency state which is sufficiently common to explain a significant fraction of the variation in HDL-C in the general population.

Adult↗
PubMed1994

Plasma lipoprotein (a) levels and fibrinolytic activity in acute myocardial infarction.

To evaluate the effects of lipoprotein (a) [Lp (a)] on the fibrinolytic system in patients with acute myocardial infarction (AMI) who underwent thrombolytic therapy with recombinant tissue-type plasminogen activator, we examined serial changes in plasma levels of Lp (a), plasminogen activator inhibitor (PAI) activity, alpha 2-plasmin inhibitor-plasmin complex (PIC) and thrombin antithrombin III complex (TAT) in venous plasma samples from 25 patients with AMI for 3 weeks. Plasma Lp (a) levels were significantly increased 5, 7, and 14 days after admission and tended to decrease by the 21st day. On the other hand, the ratio of PIC/TAT was significantly increased on the 7th day and remained high for 3 weeks (p < 0.01), while plasma PAI activity was significantly decreased on the 5th day after admission (p < 0.01). Thus, plasma fibrinolytic function is impaired in the early phase after AMI, and gradually improves over the course of 3 weeks. The increase in plasma Lp (a) levels is, therefore, not accompanied by a significant decrease in plasma fibrinolytic function in patients with AMI.

Aged↗
PubMed1994

Immunohistochemical localization of vacuolar H(+)-ATPase in osteoclasts of rat tibiae.

The localization of vacuolar H(+)-atpASE (V-ATPase) in osteoclasts of rat tibiae was examined immunohistochemically using antibodies to 57 kD and 72 kD subunits of V-ATPase, with confocal laser scanning microscopy and transmission electron microscopy. The two antibodies showed similar immunoreactivities in osteoclasts. We distinguished three patterns of immunoreactivity in osteoclasts: The first pattern was that immunoreactivity was diffusely detected in cytoplasm of osteoclasts; The second one was that osteoclasts showed intense immunoreactivity in their regions contacting with bone surface; and the last was that little immunoreactivity was seen in osteoclasts. Post-embedding methods with protein A-gold complex revealed that the subunits of V-ATPase were localized not only on the membranes of the ruffled borders of osteoclasts, but also around the Golgi apparatus and accumulated tubular lysosomes. These findings suggest that: 1) immunoreactive patterns for V-ATPase in osteoclasts reflect the polarity and activity of osteoclasts; and 2) V-ATPase on ruffled borders may be transported through tubular lysosomes.

Animals↗
PubMed1994

[Human gene therapy].

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Acquired Immunodeficiency Syndrome↗