Biomedical subjects

M Maruyama

Publications and source records attributed to M Maruyama.

At least 19 recordsLinked to original sources

PubMed1992

Evidence that [3H]glutamate binding sites are masked by biologically relevant endogenous factor on cell membranes of frog spinal cord.

We identified the possible endogenous factor effective to modulate the binding of [3H]-labeled excitatory amino acid agonists and antagonists in the 100,000 x g supernatant of Triton X-100 (0.01%)-treated cell membranes from frog spinal cords. The factor inhibited the binding of [3H]glutamate to Triton X-100-treated cell membranes, to which the binding capacity of [3H]glutamate increased much more than that to intact cell membranes. The binding capacities of [3H]AMPA (an AMPA type agonist) and [3H]CPP (an NMDA type antagonist) to cell membranes remained low by Triton treatment, but they were enhanced significantly by the addition of the factor. The effect of the factor on the [3H]kainate binding was hardly observable. The factor may provide key information on receptor structures and the classification of receptor types concerning excitatory amino acids in the mammalian central nervous system.

Animals↗

PubMed1992

Screening for germ-line mutations in familial adenomatous polyposis patients: 61 new patients and a summary of 150 unrelated patients.

We report here the result of a screening for germ-line mutations in the adenomatous polyposis coli (APC) gene in 61 new familial adenomatous polyposis (FAP) patients as well as a summary of the results of 150 patients. Examination of the entire coding region of the APC gene, based on a ribonuclease protection assay coupled with the polymerase chain reaction (PCR), disclosed mutations that were considered to cause significant defects in the APC product in 97 of 150 unrelated FAP patients. Our findings revealed the following characteristics of the germ-line mutations of APC: 1) the great majority of the mutations were found to truncate the APC product; 2) almost all of the mutations were located within the first half of the coding region; 3) no correlation was observed between the locations of germ-line mutations and extracolonic manifestations in FAP patients; 4) more than 80% of base substitutions in the APC gene were from cytosine to other nucleotides, nearly one-third of which occurred at the GpG site. Our results provide information helpful to an understanding of the APC gene and will also contribute to presymptomatic diagnosis of members in FAP families.

Adenomatous Polyposis Coli↗

PubMed1992

Fibrinolytic enzymes in ascites during experimental acute pancreatitis in rats.

The ascites accumulating during acute pancreatitis contain proteases that play a role in the progression of this disease. The proteases of the fibrinolytic system in the ascites were therefore studied in experimental acute pancreatitis induced in rats. Synthetic substrate assay and the fibrin plate method revealed high activities of proteases, including plasminogen activator, in the ascites. The plasminogen activator had a mol wt of about 50,000 by zymography. The plasminogen activator adsorbed on Lys-sepharose from the ascites was observed at the 100,000 mol wt position and in the 50,000-100,000 mol wt range on zymography and appeared at the 50,000 mol wt position after treatment by concentration. Its activity was enhanced by trypsin treatment. In other experiments, when incubated homogenate of normal pancreas lacking in zymographic activity was injected intraperitoneally into healthy rats, the recovered fluid displayed lytic zones between the 100,00 and 50,000 mol wt positions. These findings suggest that the ascites contained plasminogen activator, part of which was released by intrapancreatic substances and was present in the precursor form.

Acute Disease↗

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

Binding characteristics of naftopidil and alpha 1-adrenoceptor antagonists to prostatic alpha-adrenoceptors in benign prostatic hypertrophy.

Binding properties of naftopidil and alpha 1-adrenoceptor antagonists to alpha-adrenoceptors in prostates from benign prostatic hypertrophy (BPH) were characterized by radioreceptor assays using [3H]prazosin and [3H]rauwolscine. Specific binding of [3H]prazosin and [3H]rauwolscine in human prostatic membranes was saturable and of high affinity, and it showed a pharmacological specificity which characterized alpha 1 and alpha 2-adrenoceptors, respectively. Naftopidil and several alpha 1 antagonists competed for prostatic [3H]prazosin binding in order: R-(-)-YM-12617 greater than prazosin greater than bunazosin greater than terazosin greater than naftopidil greater than urapidil, and the inhibitory effect (Ki = 11.6 nM) of naftopidil was 10 to 45 times less potent than quinazoline derivatives such as prazosin, bunazosin and terazosin. The potencies of these antagonists in competing for [3H]prazosin binding sites in human prostates correlated well with their pharmacological potencies (pA2). Scatchard analysis indicated that the decrease of prostatic [3H]prazosin binding by naftopidil was due to a marked increase in the Kd value without a change in the Bmax value. The inhibition of prostatic [3H]prazosin binding by naftopidil was reversible. Naftopidil also inhibited prostatic [3H]rauwolscine binding (Ki = 70.0 nM). Thus, it is suggested that naftopidil antagonizes alpha 1-adrenoceptors in human prostates in a competitive and reversible manner.

Adrenergic alpha-Antagonists↗

PubMed1992

Purification and characterization of two fibrinolytic enzymes from Bothrops jararaca (jararaca) venom.

Two fibrinolytic enzymes, jararafibrase I and jararafibrase II, were purified from Bothrops jararaca venom. The purified jararafibrase I and jararafibrase II ran as single protein bands on analytical polyacrylamide gel electrophoresis and had mol. wts of 47,000 +/- 2000 and 21,400 +/- 500, respectively, by SDS-polyacrylamide gel electrophoresis. The isoelectric points of jararafibrase I and jararafibrase II were 4.6 and 6.5, respectively. The specific activities of jararafibrase I and jararafibrase II were 2.2 units/mg protein and 6.3 units/mg protein, respectively. Both enzymes exhibited no detectable plasminogen activating activity. The activity of the enzymes was completely inhibited by 1,10-phenanthroline and ethylenediaminetetraacetate, suggesting that both enzymes were metalloproteinases. Jararafibrase I and jararafibrase II had single-chain protein compositions, and the amino acid sequence up to the 49th amino acid from the NH2-terminal of jararafibrase II was: Leu-Pro-Glu-His-Gln-Arg-Tyr-Ile-Glu-Leu-Phe-Ile-Val-Val-Asp-His-Gly-Met- Phe-Met-Lys-Tyr-Asn-Gly-Asn-Ser-Asp-Lys-Ile-Arg-Arg-Arg-Ile-His-Gln- Met-Val-Asn-Ile-Met-Lys-X-Ala-Tyr-Arg-Tyr-Leu-Tyr-Ile-(X = not confirmed).

Amino Acid Sequence↗

PubMed1992

Broad substrate specificity of snake venom fibrinolytic enzymes: possible role in haemorrhage.

We found previously that two fibrinolytic enzymes (jararafibrases I and II) purified from Bothrops jararaca venom displayed a haemorrhagic activity. To elucidate the mechanisms involved and the role of the enzymatic activity in haemorrhage, the enzymatic properties of the purified enzymes were examined. The substrate specificity of the enzymes was determined using type I collagen, type IV collagen, gelatin, laminin and fibronectin as substrates. The enzymes degraded type IV collagen, gelatin, laminin and fibronectin into smaller fragments, but degraded type I collagen only partially in a non-specific manner. The specific activities of jararafibrase I for type IV collagen and gelatin were 172 +/- 5 units/mg protein and 1315 +/- 177 units/mg protein, respectively. The specific activities of jararafibrase II for type IV collagen and gelatin were 9.2 +/- 0.6 units/mg protein and 143 +/- 15 units/mg protein, respectively. It was evident that the enzymes had rather broad substrate specificities and degraded basement membrane components including type IV collagen. The number of type IV collagen units of bacterial collagenase which gave the minimal haemorrhagic dose was 191.4, while the numbers of type IV collagenase units of jararafibrases I and II which gave the minimal haemorrhagic dose were 1.5 and 0.25, respectively. It is suggested that the broad substrate specificity of the enzymes is essential for inducing haemorrhage with a single enzyme.

Animals↗

PubMed1992

Prothrombin and factor X activating properties of Bothrops erythromelas venom.

The enzymatic properties of Factor II (FII) and Factor X (FX) activators from Bothrops erythromelas venom were investigated. Both activators were inhibited by ethylenediaminetetraacetate (EDTA) and 1,10-phenanthroline, and are thought to be metalloproteinases with molecular weights of 90 kDa and 70-90 kDa, respectively. The activity of the FII activator in the crude venom was about 30 times greater than that in Oxyuranus scutellatus venom and the level of FX activator activity, which was CA2+ ion dependent, was similar to that in Daboia russelli venom. The venom also had two haemorrhagic factors (58 and 105 kDa) and two fibrinolytic enzymes (18 and 58 kDa).

Animals↗

PubMed1992

Cardioprotective effects of nicorandil.

The effects of nicorandil, a nicotinamide nitrate with K(+)-channel-opening activity, was investigated in several models of ischemia-reperfusion injury in conscious and anesthetized dogs or isolated buffer-perfused rat hearts. In several models of reversible ischemic injury (stunned myocardium) in dogs, nicorandil resulted in an enhanced recovery of regional systolic shortening during reperfusion after a single episode of coronary artery occlusion (10-15 min). These beneficial actions of nicorandil were not shared by the nitrovasodilator sodium nitroprusside but were mimicked by the selective K(+)-channel opener EMD 52692. In a model of irreversible ischemia-reperfusion injury (i.e., 2 h of coronary occlusion followed by reperfusion) in anesthetized dogs, nicorandil produced a marked reduction of myocardial infarct size. An equihypotensive dose of the calcium antagonist nifedipine had no significant effect; however, EMD 52692 produced the same reduction in infarct size as had nicorandil. In isolated, perfused rat hearts subjected to 20 min of low-flow (1.0 ml/min) global ischemia followed by 30 min of reperfusion, nicorandil (7 microM) resulted in a significant improvement in the recovery of isovolumic left ventricular minute work during reperfusion compared with untreated hearts. Finally, the results of in vitro experiments indicated that nicorandil (10(-6) to 10(-3) M) produced a concentration-dependent inhibition of superoxide anion free radical production by human and canine neutrophils. The K(+)-channel opener EMD 52692 also inhibited superoxide production in canine neutrophils. These results indicate that nicorandil is a highly efficacious myocardial protective agent in several animal models of reversible or irreversible ischemia-reperfusion injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[An outbreak of Pseudomonas folliculitis in children--the first report on Pseudomonas folliculitis in Japan].

An outbreak of Pseudomonas aeruginosa folliculitis in 6 children occurred within 5 days after playing in a tiny vinyl pool. The follicular macular or pustular eruptions were mainly distributed on the trunk. No associated symptoms were seen. The causative Pseudomonas aeruginosa strain isolated from pustules of one case belonged to serogroup E, corresponding to O-11 (Difco). The rash subsided promptly and spontaneously. Furthermore, we have encountered another case of Psedomonas folliculitis caused by P. aeruginosa serogroup G, corresponding to O-6 (Difco). The maculopustular rash was distributed on the trunk and disappeared spontaneously as the cases mentioned above. The folliculitis of this baby were probably associated with the repeated use of family bath without changing water. In U.S. and Europe Pseudomonas folliculitis have been reported very frequently, but our cases were reported for the first time in Japan.

Child↗

PubMed1992

A rapid and strong increase of plasminogen activator induced by experimental anaphylaxis in rabbits.

Anaphylactic shock was induced in rabbits by injecting bovine serum albumin (BSA) as an antigen. Measurements of the enzyme activities in the fibrinolytic system confirmed that a rapid and strong increase of plasminogen activator (PA) was induced during anaphylaxis. The euglobulin fibrinolytic activity (EFA) as estimated by the plasminogen-rich fibrin plate method rose significantly, peaking at 15 min after the BSA injection (when the arterial pressure was minimum). However, EFA was not detected by the plasminogen-poor fibrin plate method. The tissue-type PA (t-PA) activity using the natural substrate plasminogen increased significantly with a peak at 15 min. The amidolytic activity also simultaneously increased significantly using the t-PA substrate, H-D-Ile-Pro-Arg-pNA. The plasminogen activator inhibitor (PAI) activity remained at baseline levels until 30 min, but rose fourfold at 90 min. The main plasma fibrinolytic enzyme which increased in anaphylaxis was proved by zymography to be t-PA with a molecular weight (MW) of 69,000.

Amino Acid Sequence↗

PubMed1992

Pharmacological evidence for a role of ATP-dependent potassium channels in myocardial stunning.

BACKGROUND: Several recent studies suggest that activation of ATP-dependent potassium (K(ATP)) channels in the myocardium plays an important cardioprotective role during ischemia. The present study was undertaken to examine further the role of this ion channel in vivo in a model of "stunned" myocardium. METHODS AND RESULTS: Barbital-anesthetized dogs were subjected to 15 minutes of left anterior descending (LAD) coronary artery occlusion followed by 3 hours of reperfusion. Regional myocardial blood flow was measured by radioactive microspheres and segment function by sonomicrometry. Intravenous administration of the potassium channel opener aprikalim (RP 52891) at a dose that produced no significant systemic hemodynamic effects (10 micrograms/kg plus 0.1 microgram/kg/min) resulted in a marked improvement in segment shortening in the ischemic/reperfused myocardium compared with control animals (p less than 0.05) when given before the ischemic insult. However, administration of aprikalim immediately before reperfusion had no beneficial effect. Furthermore, pretreatment with the K(ATP) channel antagonist glibenclamide antagonized the recovery of contractile function afforded by aprikalim when administered at a low dose (0.3 mg/kg) that alone had no effect on postischemic recovery. In contrast, pretreatment with either a higher dose of glibenclamide (1.0 mg/kg) or the related sulfonylurea K(ATP) channel antagonist tolbutamide (100 mg/kg) resulted in a worsening of segment function after reperfusion. The ability of aprikalim and the K(ATP) channel antagonists to alter postischemic wall function occurred independently of differences in systemic hemodynamics, area at risk, and collateral blood flow during occlusion, the major determinants of the extent of myocardial stunning. CONCLUSIONS: These results suggest that opening myocardial K(ATP) channels in the ischemic heart results in a marked cardioprotective effect in stunned myocardium and that these channels may serve an endogenous function, which is to provide protection from ischemic insults.

Adenosine Triphosphate↗

PubMed1992

Interleukin 6 activity in pleural effusion. Its diagnostic value and thrombopoietic activity.

We measured interleukin 6 (IL-6) concentrations in the pleural fluid of various patients to determine its role in pathophysiology and diagnosis by using specific functional bioassay. IL-6 levels were significantly higher in exudate than in transudate (79.3 +/- 176.2 U/ml [n = 55] vs 1.7 +/- 1.8 U/ml [n = 12]; p < 0.01). Tuberculous effusion contained a significantly higher amount of IL-6 than malignant effusion (181.3 +/- 176.2 U/ml [n = 13] vs 29.4 +/- 71.5 U/ml [n = 29]; p < 0.005). Pleural IL-6 levels were invariably higher than serum IL-6 levels, and both were significantly correlated (n = 21, r = 0.632; p < 0.02). Pleural IL-6 levels were significantly correlated with lactate dehydrogenase (LDH) in pleural fluid (r = 0.392; p < 0.01), ratio of pleural/serum LDH (r = 0.571; p < 0.01), pleural adenosine deaminase activity (r = 0.599; p < 0.01), and serum C-reactive protein (r = 0.494; p < 0.01). Furthermore, IL-6 levels were significantly correlated with peripheral blood platelet counts (r = 0.447; p < 0.001). These results suggest that (1) IL-6 is produced locally in pleural space, (2) pleural IL-6 level is helpful for differential diagnosis, and (3) locally produced IL-6 could leak to circulation and cause systemic effects such as the induction of C-reactive protein and thrombocytosis.

Adenosine Deaminase↗

PubMed1992

Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Benastatins have been isolated as part of a program designed to find microorganism-produced inhibitors of glutathione S-transferase from Streptomyces sp. MI384-DF12. They were purified by chromatography of reversed-phase silica gel, silica gel and Capcell Pak C18 (HPLC) followed by solvent extraction and then isolated as yellow powders. Benastatins A and B have the molecular formulae, C30H28O7 and C30H30O7, respectively. They were competitive with 3,4-dichloronitrobenzene as the substrate, and the inhibition constants (Ki) of benastatins A and B were 5.0 x 10(-6) and 3.7 x 10(-6), respectively.

Animals↗

PubMed1992

Novel thrombolytic therapy discovered from traditional oriental medicine using the earthworm.

Since a few thousand years ago, the earthworm has been used as a drug for various diseases in China and the Far East. However, modern scientific pharmacological studies have not so far been performed. We extracted a very strong fibrinolytic enzyme from the earthworm, Lumbricus rubellus. This enzyme was heat-stable and displayed a very broad optimal pH range. Purification of the enzyme was performed and three partially purified fractions were obtained. These three fractions were further subdivided, and six purified fractions (F-I-0, 1, 2, F-II, and F-III-1,2) were finally obtained. Based on results of their enzymatic activities against various substrates, the fraction I enzymes are thought to represent chymotrypsin-like enzymes and the fraction III enzymes to represent trypsin-like enzymes. The fraction II enzyme appears to be neither a trypsin-nor chymotrypsin-like enzyme nor an elastase. We therefore designed trials for in vivo experiments on human volunteers. 120 mg of lyophilized earthworm powder was administered orally to 7 healthy volunteers (aged 28-52 years old) three times after meals every day for 17 days. Blood was withdrawn once a day before and at 1, 2, 3, 8, 11 and 17 days after commencing the administration. The fibrin degradation products (FDP) value, tissue plasminogen activator (t-PA) antigen level and t-PA activities were measured in the blood. Before the administration, the t-PA antigen level was 5.6 +/- 0.38 ng/ml, and it gradually increased until the 17th day. The FDP level was increased on the 1st and 2nd day after the administration, but had decreased and normalized by the 17th day. The fibrinolytic activities also tended to show an increase during the experiment. These results suggest that earthworm powder represents a possible oral thrombolytic agent. The earthworm enzyme may thus be applicable for treating patients with thalassemia.

Administration, Oral↗

PubMed1992

[A morphological study of pulmonary macrophages in bleomycin-injected murine models].

Pulmonary changes induced in a murine model by intraperitoneal injections of bleomycin were morphologically studied by light and electron microscopy. The number of pulmonary macrophages and the distribution of fibronectin in these cells were evaluated by acid phosphatase and affinity staining using anti-fibronectin horseradish peroxidase conjugates. The onset of acute inflammation occurred 4 days after intraperitoneal injection of bleomycin and reached its peak on the 14th day post-injection. The inflammatory reaction then gradually decreased. Areas of subpleural fibrosis was observed on day 42. On day 14, the ratio of the macrophage in bleomycin-treated mice to that in control mice was 5:1. Many activated and foamy macrophages were observed at that time. These findings indicate that macrophage turnover activity is remarkably increased during the acute inflammatory phase. Fibronectin was detected in the cytoplasm of macrophages on day 14, 21, and 28. It was also detected in both alveolar capillary and epithelial basal lamina as well as in interstitial collagen fibers. On day 42, fibronectin staining was strongly positive in areas of subpleural fibrosis. These results suggest that fibronectin released from pulmonary macrophages plays a role in the process of pulmonary fibrosis.

Animals↗

PubMed1992

[Coronary artery bypass grafting: does the use of arterial graft for coronary artery bypass grafting increase surgical risk?].

Since April in 1988 coronary artery bypass grafting (CABG) was performed in 177 patients and the clinical results were compared in SVG-group (n = 37) in which only saphenous vein graft (SVG) was used as a graft conduit and AG-group in which one arterial graft (AG-1 group, n = 92) or more than two arterial grafts were used (AG-2 group, n = 48). In SVG-group the age was older than that in AG-group, while coronary vessels were most involved in AG-2 group and the mean number of distal anastomosis increased more in AG-group. The total pump time and aortic cross clamping time showed no significant differences among the groups. Furthermore, the occurrence of perioperative myocardial infarction, requirement of intra-aortic balloon pumping, frequency of re-chest open for hemorrhage, or sternal infection showed no significant differences among the groups. Postoperative hospital deaths were in four (three cardiac deaths) of SVG-group and four (one cardiac and two graft-versus-host disease) of AG-group. These results suggest that the use of AG does not increase surgical risk and AG can be positively used for CABG.

Adolescent↗

PubMed1992

[A case of nonbacterial thrombotic endocarditis presenting positive findings by two-dimensional echocardiography].

A 55-year-old woman was admitted to our hospital because of left hemiparesis. Brain CT and cerebral angiography demonstrated cerebral embolism due to occlusion of the sphenoidal part of the right middle cerebral artery. Two-dimensional echocardiography revealed mitral valve vegetation measuring 10 x 7 mm and slight mitral-valve regurgitation. Blood cultures were negative. She developed disseminated intravascular coagulation. Chest roentgenography and abdominal ultrasonography showed multiple liver and lung tumors, but she died before the primary lesion was detected. At autopsy, adenocarcinoma of the gall bladder was found. Friable vegetation was attached to the auricular surface of the mitral valve. Microscopic examination confirmed the diagnosis of nonbacterial thrombotic endocarditis. Although echocardiography is an important tool for diagnosing nonbacterial thrombotic endocarditis, few reports have described echocardiographic detection of nonbacterial thrombotic endocarditis. Because vegetation of nonbacterial thrombotic endocarditis is smaller than that of infective endocarditis (less than 3 mm), it is difficult for echocardiography to detect nonbacterial thrombotic endocarditis. Thus, a negative examination does not exclude the possibility of nonbacterial thrombotic endocarditis. To make an antemortem diagnosis of nonbacterial thrombotic endocarditis, we must perform echocardiography carefully in cases of cerebral infarction with carcinoma and/or DIC.

Adenocarcinoma↗