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Biomedical subjects

Y Nakashima

Publications and source records attributed to Y Nakashima.

At least 361 records · Page 20Linked to original sources
PubMed1991

Monoclonal antibody to the corneal endothelium: partial characterization of the antigen and its expression in fetal and adult rabbits.

Monoclonal antibodies (mAbs) were developed against corneal endothelial cells (CECs) using cultured bovine CECs as immunogens by the mouse hybridoma technique. One of these mAbs, KP14D10 (IgM type), reacted specifically with CECs in human, bovine and rabbit ocular tissues as judged by immunohistochemical methods. This mAb also reacted with some epithelial cells of human esophageal and gastric glands but not with those of bovine and rabbit origin. The molecular weight of the antigen was determined to be 60,000 Da by the immunoblotting method. This antigenicity was apparently decreased by treatment with hyaluronidase, trypsin, and pronase. In the immunohistochemical study of rabbit fetal corneas, the immunofluorescence appeared specifically in the CECs after the 15th day of gestation and its intensity became stronger as gestation advanced. These results suggest that this antibody would be a valuable tool in the further analysis of corneal development and of divese pathological alterations of CECs.

Animals↗
PubMed1991

Hormonal regulation of plasminogen activator and peroxidase activities in 7,12-dimethylbenz(a)anthracene-induced rat mammary tumors and the rat uterus.

Oophorectomy was found to decrease the plasminogen activator activity of rat mammary tumors induced by 7,12-dimethylbenz(a)anthracene (DMBA) to less than 7 per cent, while in vivo estradiol treatment restored its activity in a dose dependent fashion. The peroxidase activity was not changed either by oophorectomy or by the administration of estrogen. In the rat uterus, plasminogen activator activity was not changed by oophorectomy or by the administration of estrogen, however, its peroxidase activity decreased to less than 2 per cent following oophorectomy, while estrogen administration restored its activity. Estrogen regulated plasminogen activator activity in the DMBA-induced rat mammary tumors but not in the uterus and thus, the specific hormonal regulation of this enzyme may be an important factor for the hormonal dependent growth of such tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1991

Extracellular and cell-associated localizations of plasminogen activators and plasminogen activator inhibitor-1 in cultured endothelium.

The extracellular localizations of urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) were examined in cultured bovine capillary endothelial cells (BCEs) by an immunofluorescence method using BCEs treated with or without saponin and focal contact preparations. The specific immunofluorescence of cell surface uPA showed a patchy or strand-like distribution and was colocalized with vinculin strands indicating that uPA secreted from BCEs was mainly deposited at the cell surface of focal contacts. BCEs at a subconfluent density showed a higher intensity of specific immunofluorescence for uPA than when they were at a confluent density. tPA was observed over the dorsal surface of cultured BCEs and accentuated at their margins, suggesting that tPA was diffusely distributed on the luminal surface of BCEs in vivo. PAI-1 was distributed in the extracellular matrix under cultured BCEs. These findings suggest that uPA and PAI-1 are located under BCEs participating in the regulation of proteolytic activities provoked by plasminogen-PAs-plasmin system in vivo. The localization of tPA appears to be consistent with its function, which is to maintain the fluidity of the blood and to initiate thrombolysis in vivo.

Actins↗
PubMed1991

Stimulation by acetylcholine and inhibition by norepinephrine of transglutaminase activity in superior cervical ganglia excised from adult rats.

Very rapid changes in activity of transglutaminase (TG), a calcium-dependent enzyme contributing to cross-linkage formation of intracellular polypeptide chains, were observed in vitro in rat superior cervical ganglion (SCG) and nodose ganglion (NG) following application of cholinergic or adrenergic agonists and antagonists. In SCG, a tissue rich in synapses, the depolarizing agent acetylcholine (ACh, 0.1 mM) produced an 8.7-fold increase in TG activity within 5 min that lasted for 30 min and returned to control levels by 2 h. In contrast, the ACh-induced increase in TG activity in NG, a tissue containing neuronal cell bodies with few synapses, was more gradual and of smaller magnitude, reaching a peak of approximately 2.4 times control by 30 min that was maintained for at least 2 h. In both tissues the ACh-stimulation was effectively blocked by the nicotinic antagonist, hexamethonium (0.1 mM), whereas the muscarinic antagonist, atropine (0.1 mM), partially blocked the ACh effect in SCG and was without effect in NG. Addition of the hyperpolarizing adrenergic agonists norepinephrine (NE, 50 microM), isoproterenol (0.2 mM) or dopamine (0.1 mM) produced an inhibition of TG activity in SCG but had no effect in NG. The inhibitory effects of the adrenergic agonists in SCG were blocked by the beta-adrenergic antagonist, propranolol (10 microM) and alpha 2-adrenergic antagonist, yohimbine (10 microM). A kinetic study revealed that the ACh-induced stimulation of TG activity in SCG and NG was a result of decrease in apparent Km and an increase in Vmax value, whereas the NE-induced inhibition of SCG enzyme activity was a result of an increased Km and decreased Vmax. 45Ca2+ influx into excised SCG or NG was significantly reduced by the application of either ACh or NE. The ACh inhibition was effectively blocked by either hexamethonium or atropine. The NE inhibition was more effectively blocked by yohimbine than by propranolol. These results suggest that the rapid alterations of TG activity in SCG produced by cholinergic and adrenergic neurotransmitters are attributable to the processes of receptor-mediated depolarization and hyperpolarization, respectively, via modulation of nerve-impulse-induced Ca2+ fluxes during synaptic activity.

Acetylcholine↗
PubMed1991

The possible involvement of protein synthesis in the injection of PL-1 phage genome into its host, Lactobacillus casei.

The process of genome DNA injection, after adsorption, by phage PL-1 into host cells of Lactobacillus casei was monitored by using the electron microscope. Injection of DNA was inhibited by the protein-synthesis inhibitors chloramphenicol and erythromycin at concentrations where the colony-forming ability of cells not infected by phage was unaffected. The results suggest that protein synthesis may be involved in some way in the process of genome injection.

Bacterial Proteins↗
PubMed1991

Stimulation of transglutaminase activity by GM1-ganglioside and alpha-sialylcholesterol in superior cervical and nodose ganglia excised from adult rat.

Changes in transglutaminase (TG) activity in superior cervical ganglia (SCG) and nodose ganglia (NG) excised from adult rats were examined following application of selected membrane transport-altering agents, including GM1-ganglioside (GM1) and alpha-sialylcholesterol (alpha-SC). Although TG activity of freshly dissected SCG and NG was relatively low, it increased gradually during 30 min of incubation, and it stayed at this elevated level for 2 h. Addition of alpha-SC at its maximal effective concentration, 20 microM, stimulated TG activity more than eightfold in SCG and more than twofold in NG by 30 min. Addition of GM1 at its most effective concentration, 5 nM, had similar effects, but of lesser magnitude. Cycloheximide, a potent inhibitor of protein biosynthesis, did not affect the GM1- or alpha-SC-evoked increases in ganglionic TG activity, suggesting that enzyme activation rather than synthesis of new enzyme was occurring. The stimulation of TG activity in both ganglia caused by either GM1 or alpha-SC was associated with a decrease in Km and an increase in Vmax values. Addition of cholera toxin B, which specifically masks the oligosaccharide chain of GM1, reduced the GM1-induced increase in TG activity by approximately 60% in SCG and 88% in NG. The alpha-SC-induced increase in TG activity was only partially mimicked by free cholesterol. Although application of either dibutyryl cyclic AMP or dibutyryl cyclic GMP produced little change in TG activity of either ganglion, phorbol ester clearly inhibited the enzymic activity. Because TG is a calcium-dependent enzyme, we measured 45Ca2+ influx into either ganglion, and found that it was reduced by GM1 and alpha-SC in SCG and by alpha-SC in NG.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

A quantitative histopathological study of right bundle branch block complicating acute anteroseptal myocardial infarction.

The aim of the present study was to evaluate whether necrosis of the right bundle branch is responsible for development of right bundle branch block in acute myocardial infarction. Twenty patients with acute anteroseptal myocardial infarction were studied--10 with right bundle branch block (group A) and 10 without (group B)--to evaluate by serial sectioning the pathological extent of myocardial infarction surrounding the right bundle branch and also that of right bundle branch necrosis. Myocardial infarction reached the right bundle branch more than 8 mm above the moderator band in all of group A, whereas myocardial infarction reached the right bundle branch less than 3 mm above the moderator band in only three patients in group B. Nine hearts in group A showed significant necrosis of the right bundle branch. In group B and in one case with transient right bundle branch block no necrosis was found. The occurrence of right bundle branch block was almost entirely explained by necrosis of the right bundle branch, but transient right bundle branch block did develop without necrosis of the right bundle branch.

Aged↗
PubMed1991

Effects of hydrogen ion on the changes in adenosine production in the isolated rat heart perfused at a constant flow system.

This study was designed to clarify the relationship between the change in H+ and the nucleoside concentration at a constant coronary flow rate using a Langendorff system. Wistar rat hearts were perfused with Krebs-Henseleit solution (control, pH 7.4) modified to be either acidotic or alkalotic. Coronary perfusion pressure (CPP), left ventricular pressure, and myocardial oxygen consumption were decreased in the acidotic perfusate. On the other hand, these parameters increased in the alkalotic perfusate. Adenosine production in the acidotic perfusate significantly decreased while it significantly increased in the alkalotic perfusate. Furthermore, there was a significant positive correlation between both the percent change in adenosine production and the percent change in CPP in acidosis and alkalosis. It is suggested from these results that the hydrogen ion affects the adenosine metabolism and that the change in coronary blood flow by H+ is at least partly regulated by adenosine.

Acid-Base Equilibrium↗
PubMed1991

Protein structure and cDNA nucleotide sequence of the Japanese quail alpha A globin.

The primary structure of the alpha polypeptide chain (alpha A) of the major component (QII) of Japanese quail hemoglobin was determined by protein and cDNA sequence analysis. The amino-acid sequences of all the soluble tryptic peptides were determined by the conventional protein sequencing technology. The sequence of the remaining portion, which contained an insoluble "core region", was determined through determination of the cDNA nucleotide sequence. The cDNA clones coding for the alpha A globin were isolated from the quail reticulocyte cDNA library, mapped by restriction enzyme digestion, and the nucleotide sequence was determined completely. The primary structure of quail alpha A globin shows a close similarity to that of chicken alpha A globin.

Amino Acid Sequence↗
PubMed1991

Ruptured chordae tendineae in acromegaly. An autopsy case.

A 57-year-old woman with acromegaly associated with mitral chordal rupture is reported. She was noted to have abnormal development in the size of her hands and feet in childhood. She occasionally suffered from shortness of breath on exertion and nocturnal dyspnea for several years, and was diagnosed and treated as having congestive heart failure due to valvular heart disease. On admission to our hospital, chordal rupture was suspected on the basis of M-mode and two-dimensional echocardiography. Seven years after discharge, she died of congestive heart failure. On autopsy, the heart weight and ventricular wall thickness were increased. Rupture of the posterior chordae was confirmed, but evidence of an old myocardial infarction was not found. There was severe interstitial fibrosis in the left ventricular wall. A possible etiology of the chordal rupture in this case was thought to be the excessive stretching caused by the disproportional visceromegaly of the heart.

Acromegaly↗
PubMed1991

Effect of different volatile fatty acids mixtures on energy metabolism in cattle.

Four Friesian steers (mean BW = 282 kg) were given mixtures of VFA and casein by intragastric infusion to give a total energy input of 675 kJ/kg BW.75. Casein supplied 16.3% of the energy and 777 mg N/kg BW.75. The molar proportion of butyric acid was held constant at 8 mol/100 mol, and the acetic and propionic acids varied inversely. Acetic acid was varied in 12 increments from 11 to 91 mol/100 mol and propionic acid proportion varied inversely. Heat production, blood (urea, insulin, beta-hydroxybutyrate, free fatty acids) and urine metabolites (urea, N, VFA) were measured. There were no differences (P greater than .05) in heat production until the acetic acid proportions exceeded approximately 90 mol/100 mol, at which point there was a decrease in heat production (P less than .05) accompanied by a considerable excretion of acetic acid in the urine. Above 80 mol/100 mol acetic acid, beta-hydroxybutyrate was greatly elevated, accompanied by a small decrease in blood glucose and blood insulin together with an increase in blood free fatty acid concentration. There was also an elevation of N excretion in the urine. When the proportion of propionic acid exceeded 76 mol/100 mol there were some metabolic disturbances resulting in blood hemolysis, an increase in N excretion in the urine, and nervous disposition of the animals. It is concluded that differences in heat production between roughage and concentrate diets are not likely to be a result of differences in the energetic response to different proportions of VFA. Differences in activity during standing, feeding, and ruminating may, therefore, be more important.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Embryonal carcinoma of the testis after acute myelomonocytic leukemia: a case report.

A case of embryonal carcinoma of the testis after acute myelomonocytic leukemia is reported. The interval between the initial diagnosis of leukemia and the appearance of embryonal carcinoma was almost three years. Although the patient had received neither irradiation nor alkylating agents, the case is regarded as one of secondary malignancy. Possible contributing factors are discussed.

Adolescent↗
PubMed1991

WPW syndrome complicated by another cardiac disorder.

During the past 28 months, 16 cases of WPW syndrome were operated on at Hiroshima University Hospital. Two cases were complicated by other cardiac disorders which accelerated tachycardia, making diagnosis difficult. One of these cases showed serious mitral regurgitation, due to infective endocarditis and the patient suffered cardiac failure accompanied by paroxysmal tachycardia not responsive to medical therapy or cardioversion. A complex rhythm with atrial fibrillation and antegrade conduction rhythm through the accessory pathway made diagnosis and therapy quite difficult. The condition of the other patient was associated with myocardial bridging which caused angina pectoris during paroxysmal tachycardia. Myocardial scintigraphy showed myocardial ischemia in the antero-lateral area of the left ventricle. In the former case, mitral valve replacement and interruption of the accessory pathway were undergone simultaneously. In the latter case, myotomy of the muscle on segment 7 was conducted, following interruption of the accessory pathway.

Adult↗
PubMed1991

[CDDP-ip PMUE therapy in gastric cancer cases with liver metastasis].

To reduce liver metastasis and prevent carcinomatous peritonitis, we employed CDDP-ip PMUE therapy in gastric cancer cases with liver metastasis exceeding P0H2S2. Therapy consisted of cis-diammine-dichloroplatinum-ip (CDDP-ip), mitomycin C (MMC), uracil and futraful (UFT) and etoposide. From January 1990 to March 1991, primary lesions were resected in 6 gastric cancer cases with liver metastasis exceeding H2. On the basis of therapy, subjects were classified into 2 groups and the therapeutic effects were compared between them. One group was composed of 3 patients who were placed on CDDP-ip PMUE therapy beginning the 14th day after gastrectomy. The other group was composed of 3 patients who received only UFT oral administration (300 mg/body). As a rule, the following was the CDDP-ip PMUE therapy schedule: CDDP intraperitoneal administration (75 mg/m2) and MMC intravenous injection (10 mg/body) on day 1; etoposide intravenous injection (30 mg/body) on days 2 to 6; and consecutive UFT oral administration (300 mg/body). One case showed MR in a metastatic liver lesion, but treatment proved ineffective in the other cases. Although the 2 patients in the CDDP-ip PMUE therapy group, surviving 315 and 216 days, respectively, died of primary disease and hepatic insufficiency due to an increase in metastatic liver lesions, the third patient has been in good condition for 175 days. This therapy was thought to have prolonged survival. The post-operative survival period in the group of patients receiving only UFT oral administration ranged from 36 to 243 days, with all patients dying of primary disease. The main adverse effects of this therapy (i.e., digestive symptoms, leukopenia, and thrombocytopenia) were slight and transient in all cases. Because the subjects studied were gastric cancer cases exceeding H2, the present investigation resulted in the increase of metastatic liver lesions, a problem to be studied in future.

Administration, Oral↗
PubMed1991

[Effect of gastrectomy on release of gut hormones].

We investigated the effect of gastrectomy on the digestive system in 87 postoperative long-term survivors under test meal or egg yolk load. After test meal, gastrin and secretin responses were decreased in each of groups of proximal gastrectomy (PG), distal gastrectomy with Billroth-I (DG-B1), that with Billroth-II (DG-B2), total gastrectomy with interposition (TG-I), and that with Roux-Y (TG-RY). However, sufficient acid-secretors after partial gastrectomy showed secretin responses comparable to controls. Furthermore, cases of total gastrectomy given betain-hydrochloride with test meal increased secretin responses. Serum glucose response was higher in the TG-RY group while insulin response was high in the TG-RY and DG-B2 groups, compared with controls. GLI response was high in all groups compared with controls. Postgastrectomy gallstone occurred in 11.6%. Yolk-induced contraction of the gallbladder was decreased, and CCK release increased, for several years postoperatively. Gallbladder contraction with CCK was reduced for one year postoperatively. The contraction was reduced in persons with gallstone than those without it. This study shows that the digestive function after gastrectomy depends on acidification and duodenal passage of food, and that reduced contraction with CCK plays an important role in hypokinesis of the gallbladder.

Animals↗
PubMed1991

Diastolic filling abnormality modified by left ventricular asynchrony in essential hypertension.

Left ventricular (LV) asynchrony has been demonstrated to result in diastolic dysfunction. To test the hypothesis that altered LV synchrony interferes with LV diastolic function in essential hypertensive patients (HT), we performed radionuclide ventriculography and echocardiography in 38 HT and 11 normotensive subjects. LV diastolic asynchrony was measured as the sum (total delta t) of the absolute values of the time difference between global peak filling rate (PFR) and regional PFR. Global PFR and time to PFR were significantly reduced in HT. Although total delta t did not differ between two groups, total delta t significantly correlated with PFR (r = -0.44, p less than 0.01) in HT. Moreover, total delta t positively related to LV endsystolic stress and inversely related to LV ejection fraction in HT. Thus, LV asynchrony, in part, plays a role in early diastolic filling abnormality in hypertensive patients.

Adult↗