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Biomedical subjects

M Abe

Publications and source records attributed to M Abe.

At least 1,297 records · Page 72Linked to original sources
PubMed1984

Effect of sodium butyrate on human breast carcinoma (MCF-7) cellular proliferation, morphology, and CEA production.

Sodium butyrate is a potent inducer of leukemic cell differentiation. This agent also affects epithelial cell proliferation and gene expression. The present study demonstrates that sodium butyrate slows proliferation and induces morphologic changes in human MCF-7 breast carcinoma cells. The results also demonstrate that butyrate-treated MCF-7 cells have enhanced expression of carcinoembryonic antigen. These effects are related to butyrate concentration and duration of exposure. The present findings may provide a model for studying maturation of human breast cancer cells.

Breast Neoplasms↗
PubMed1984

Effects of l-carnitine on action potential of canine papillary muscle during hypoxic perfusion.

Under hypoxic (95% N2 + 5% CO2) perfusion, electrophysiological effects of L-carnitine on canine papillary muscles were studied using standard microelectrode techniques. During hypoxic perfusion for 60 min, resting membrane potential (RMP), action potential amplitude (APA) and maximum upstroke velocity of phase 0 were decreased, and action potential duration (APD) and effective refractory period (ERP) were shortened. Application of L-carnitine 25 mM under hypoxic perfusion increased RMP and APA and prolonged APD and ERP significantly. As effects of L-carnitine during hypoxic perfusion might be that of hypertonicity, effects of sucrose of the same tonicity as L-carnitine were studied under hypoxia. Sucrose did not cause significant changes on various parameters of action potential compared with hypoxic perfusion. It was suggested that the increase in RMP, and the prolongation of APD and ERP might be caused by an increase in intracellular ATP content. The findings in this study could be an explanation of possible antiarrhythmic effects of L-carnitine.

Action Potentials↗
PubMed1984

Effect of palmitoyl carnitine on Na+, K+-ATPase and adenylate cyclase activity of canine myocardial sarcolemma.

The accumulation of long chain of acyl carnitine, which is thought to exaggerate myocardial ischemic damage, has been demonstrated in ischemic myocardium. The purpose of this study was to determine the effect of palmitoyl carnitine on the Na+, K+-ATPase and adenylate cyclase activity of myocardial sarcolemma in vitro. Controversial views exist at present regarding the effect of palmitoyl carnitine on Na+, K+-ATPase. Wood et al. [23] observed that palmitoyl carnitine inhibited the activity of Na+, K+-ATPase but this inhibition was not observed by Owens et al. [17]. We did observe an inhibition of Na+, K+-ATPase by palmitoyl carnitine. The 50% inhibition of the maximum activity was observed at a palmitoyl carnitine concentration of 110 microM and complete inhibition at 160 microM. Adenylate cyclase activity was inhibited by palmitoyl carnitine irrespective of the assay conditions. The (isoproterenol + GTP)-stimulated activity, fluoride-stimulated activity and basal activity with Mg-ATP or Mn-ATP as a substrate were all inhibited though to varying degrees. The 50% inhibition of adenylate cyclase activity was observed at 84 microM, 94 microM, 200 microM and 105 microM of palmitoyl carnitine in the above mentioned order. The inhibition curve showed a shoulder or even a peak at about 75 microM of palmitoyl carnitine. It is suggested that elevated levels of palmitoyl carnitine in ischemic myocardium may play a role in inhibiting sarcolemmal function.

Adenylyl Cyclase Inhibitors↗
PubMed1984

Effects of methylglyoxal bis(guanylhydrazone) on tumour and skin responses to hyperthermia in mice.

Effects of methylglyoxal bis(guanylhydrazone) (MGBG) on tumour and skin responses to hyperthermia (42 degrees C) were examined in C3H mice. MGBG (50 mg/kg) was administered intraperitoneally to mice 4 hours before hyperthermic treatment. The tumour (FM3A) growth time was elongated by an amount dependent on the exposure time of treatment at 42 degrees C (60, 90 and 120 min). Pre-treatment of mice with MGBG (50 mg/kg, i.p.) apparently further lengthened the tumour growth time after treatment at 42 degrees C. No significant damage of foot skin was caused by 42 degrees C hyperthermia. Pre-treatment with MGBG did not make the foot skin susceptible to the heating. From these findings, it can be considered that MGBG or related less-toxic compounds may have a clinical advantage for the mild (42 degrees C) hyperthermic treatment in cancer therapy.

Animals↗
PubMed1984

Differential reactivity of a novel monoclonal antibody (DF3) with human malignant versus benign breast tumors.

We have defined a human breast tumor associated antigen using a murine monoclonal antibody (MAb DF3) prepared against a membrane-enriched fraction of a human breast carcinoma. This antigen has a MW of 290 kD and is detectable on the cell surface of human breast carcinoma cells using a live cell radioimmunoassay and fluorescence flow cytometry. More important, immunoperoxidase staining with MAb DF3 clearly distinguishes malignant and benign breast lesions. A cytoplasmic staining pattern has been observed with 40 of 51 (78%) breast carcinomas, but only one of 13 fibroadenoma or fibrocystic disease specimens. In contrast, reactivity of benign breast lesions with MAb DF3 primarily occurs along apical borders on ductules. These results demonstrate that the DF3 antigen is present on apical borders of more differentiated secretory mammary epithelial cells and in the cytosol of less differentiated cells.

Adenofibroma↗
PubMed1984

Genetically regulated expression of UDP-N-acetylgalactosamine: GM3(NeuGc) N-acetylgalactosaminyltransferase [EC 2.4.1.92] activity in mouse liver.

GM2 containing NeuGc was a major ganglioside in the liver of mouse strains such as BALB/c, DBA/2, C3H/He, and C57BL/10, whereas WHT/Ht mouse liver did not contain GM2(NeuGc) but contained GM3(NeuGc) as a major ganglioside. Since GM3(NeuGc) is a biosynthetic precursor of GM2(NeuGc), WHT/Ht liver was considered to lack the ability to synthesize GM2(NeuGc) from GM3(NeuGc) (Hashimoto, Y., et al. (1983) J. Biochem. 93, 895-901). In this study we measured the activity of UDP-N-acetylgalactosamine : GM3(NeuGc) N-acetylgalactosaminyltransferase in the liver of BALB/c, WHT/Ht, and their progeny. The transferase activity in the microsomal fraction of BALB/c liver was 2.10 +/- 0.32 X 10(-5) units/mg protein (means +/- S.D.), whereas no activity was detected in that of WHT/Ht liver, F1 hybrids between BALB/c and WHT/Ht expressed GM2(NeuGc) as well as the enzyme activity, the level of which was almost half that in BALB/c liver 1.10 +/- 0.12 X 10(-5) units/mg protein). The backcross generation of F1 to WHT/Ht segregated into two groups with respect to expression of GM2(NeuGc) and the transferase activity: 11 of the 21 mice analyzed expressed both GM2(NeuGc) and the transferase activity (1.28 +/- 0.18 X 10(-5) units/mg protein), whereas the rest expressed neither. These results suggest that the expression of GM2(NeuGc) is directly regulated by the activity of UDP-N-acetylgalactosamine: GM3(NeuGc) N-acetylgalactosaminyltransferase in mouse liver.

Animals↗
PubMed1984

Long-term cultivation of certain rumen protozoa in a continuous fermentation system supplemented with sponge materials.

Inert polyurethane-sponge cubes were added to an 'artificial rumen' fermenter. With crushed barley as protozoal substrate this system maintained a population of Entodinia in both substrate bags and sponge cubes for 64 d in numbers (1 X 10(6)/ml) comparable with those found in vivo. This culture was more tolerant of variations in mechanical agitation and size and shape of substrate bags than a similar culture without the sponge cubes. The extent of protozoal sequestration, 2 h after feeding, on to the sponge cubes as well as on to acetone-treated hay was evaluated. The bags of acetone-treated hay and barley, and those of sponge cubes and barley could sequestrate the protozoa to the same extent as normal hay and barley. Based on the results of the short-term experiments and those of the long-term experiment with sponge cubes, a polyurethane-sponge wall was added to the inside of the fermenter. This system maintained a varied protozoal population including large protozoa, holotrichs and Entodinia with a normal fermentation. The molar percentages of butyrate in the total volatile fatty acid (VFA) in each part of the fermenter with a sponge wall were higher than those in a fermenter without a sponge wall, suggesting that there was high protozoal activity related to the sponge wall. These results show that the introduction of the sponge wall to the fermenter produced an enlargement of the area for protozoal sequestration and a suitable micro-habitat for the maintenance of Entodinia , large protozoa and holotrichs .

Animals↗
PubMed1984

Specific phases of root hair attachment in the Rhizobium trifolii-clover symbiosis.

The time course and orientation of attachment of Rhizobium trifolii 0403 to white clover root hairs was examined in slide cultures by light and electron microscopy. Inocula were grown for 5 days on defined BIII agar medium and represented the large subpopulation of fully encapsulated single cells which uniformly bind the clover lectin trifoliin A. When 10(7) cells or more were added per seedling, bacteria attached within minutes, forming randomly oriented clumps at the root hair tips. Several hours later, single cells attached polarly to the sides of the root hair. This sequence of attachment to clover root hairs was selective for R. trifolii at inoculum sizes of 10(7) to 4 X 10(8) per seedling, specifically inhibited if 2-deoxy-D-glucose, a hapten for trifoliin A, was present in the inoculum, and not observed when 4 X 10(8) cells were added to alfalfa seedling roots or to large clover root cell wall fragments which lacked trifoliin A but still had trifoliin A receptors. Once attached, R. trifolii 0403 became progressively less detachable with 2-deoxy-D-glucose. At smaller inoculum sizes (10(5) to 10(6) cells per seedling), there was no immediate clumping of R. trifolii at clover root hair tips, although polar binding of bacteria along the root hair surface was observed after 4 h. The interface between polarly attached bacteria and the root hair cell wall was shown to contain trifoliin A by immunofluorescence microscopy. Also, this interface was shown by transmission electron microscopy to contain electron-dense granules of host origin. Scanning electron microscopy revealed an accumulation of extracellular microfibrils associated with the lateral and polar surfaces of the attached bacteria, detectable after 12 h of incubation with seedling roots. At this same time, there was a significant reduction in the effectiveness of 2-deoxy-D-glucose in dislodging bacteria already attached to root hairs and an increase in firm attachment of bacteria to the root hair surface, which withstood the hydrodynamic shear forces of high-speed vortexing. These results are interpreted as a sequence of phases in attachment, beginning with specific reversible interactions between bacterial and plant surfaces (phase I attachment), followed by production of extracellular microfibrils which firmly anchor the bacterium to the root hair (phase 2 adhesion). Thus, attachment of R. trifolii to clover root hairs is a specific process requiring more than just the inherent adhesiveness of the bacteria to the plant cell wall.(ABSTRACT TRUNCATED AT 400 WORDS)

Microscopy, Phase-Contrast↗
PubMed1984

Bacteriophage-induced acidic heteropolysaccharide lyases that convert the acidic heteropolysaccharides of Rhizobium trifolii into oligosaccharide units.

Acidic heteropolysaccharide lyases from lysates of phages 4S and BY15 grown on Rhizobium trifolii 4S and R. trifolii 0403, respectively, were used to analyze the capsular and excreted extracellular acidic polysaccharides of R. trifolii 0403. The activities of the enzymes as measured by viscometry were enhanced by the addition of calcium. The oligosaccharide products obtained by depolymerase digestion of the polysaccharides isolated from cells grown on agar plates for 5 days were isolated by gel filtration and had a glycosyl composition of glucose, galactose, glucuronic acid, and alpha-linked 4-deoxy-L-threo-hex-4-enopyranosyluronic acid in an approximate molar ratio of 5:1:1:1. This latter component was identified by 1H-nuclear magnetic resonance spectroscopy and confirmed by UV spectroscopy, ozonolysis, and its reactivity with thiobarbituric acid. The oligosaccharide had glucose as the reducing terminus, 4-deoxy-L-threo-hex-4-enopyranosyluronic acid as the enzymatically generated nonreducing terminus, and galactose as the terminus of the branched chain. The noncarbohydrate components of the oligosaccharides were acetate, ketal-linked pyruvate, and ether-linked 3-hydroxybutyrate. The mode of action of the enzymes was by beta-elimination from a uronic acid residue with concomitant loss of the glycosyl component substituted at C-4. The 235-nm absorbing properties of the resulting terminal unsaturated sugar were used to study the kinetics of depolymerization of the capsular and excreted extracellular acidic polysaccharides, using the enzyme from phage BY15. The two substrates exhibited different kinetics of depolymerization, and the oligosaccharide products differed in the amount of noncarbohydrate substituents, indicating that the acidic capsular and excreted extracellular polysaccharides from 5-day-old cultures of R. trifolii 0403 were different.

Bacteriophages↗
PubMed1984

Stimulation of clover root hair infection by lectin-binding oligosaccharides from the capsular and extracellular polysaccharides of Rhizobium trifolii.

A polysaccharide depolymerase isolated from the phage lysate of Rhizobium trifolii 4S was used to fragment capsular polysaccharides (CPS) and extracellular polysaccharides (EPS) of R. trifolii 0403 into oligosaccharides. These products were analyzed for clover lectin (trifoliin A)-binding ability, effect on infection of white clover root hairs, and changes in glycosyl and noncarbohydrate composition with culture age. The oligosaccharides from CPS of cultures grown on agar plates for 3, 5, and 7 days exhibited lectin-binding ability at levels similar to those of the corresponding intact CPS. The intact EPS did not bind to clover lectin, although the oligosaccharide fragments from EPS did. In contrast, oligosaccharides from deacetylated CPS had less than half the lectin-binding ability of the native polysaccharide substrate. The CPS from 5-day-old cultures, its corresponding oligosaccharide fragments, and the oligosaccharide fragments of EPS from 5-day-old cultures, all at a concentration of 2.5 micrograms per seedling, stimulated infection thread formation in root hairs of clover seedlings inoculated with R. trifolii 0403. Thus, this bacteriophage-induced polysaccharide depolymerase converted the acidic CPS and EPS of R. trifolii 0403 into biologically active oligosaccharides capable of binding trifoliin A and stimulating root hair infection. The amount of the noncarbohydrate substitutions (pyruvate, acetate, and ether-linked 3-hydroxybutyrate) in the CPS oligosaccharides changed with culture age as shown by 1H-nuclear magnetic resonance spectroscopy. The binding of trifoliin A, therefore, appears to be sensitive to changes in the degree of substitution of noncarbohydrate substitutions in the CPS of R. trifolii 0403.

Bacteriophages↗
PubMed1984

Gallbladder necrosis after transcatheter hepatic arterial embolization: a technique to avoid this complication.

We present a technique used to avoid unnecessary embolization of the cystic artery in the treatment of hepatoma by transcatheter arterial embolization. A special long tapering catheter that is flexible and soft enough to be inserted into the distal small branches of the heptic artery is used. Embolic material ( Oxycel , absorbable cellulose) was mixed with Mitocin -C (mitomycin) and contrast material. This mixture will help to avoid reflux.

Carcinoma, Hepatocellular↗
PubMed1984

Hypertensive crisis induced by metoclopramide in patient with pheochromocytoma.

A hypertensive crisis associated with evidence of catecholamine release was induced following intravenous administration of 10 mg metoclopramide in a woman with pheochromocytoma and in whom the tyramine test was negative. After removal of the tumor, blood-pressure and plasma catecholamine concentrations were not influenced by the administration of metoclopramide. It is suggested that the mechanism of hypertensive crises induced by metoclopramide may not be due to a direct catecholamine releasing effect from the tumor or sympathetic nerve endings, but rather to its presynaptic dopaminergic blocking effect which would indirectly release catecholamines.

Adrenal Gland Neoplasms↗
PubMed1984

Effects of brovincamine on the autonomic nervous function in the dog and rat.

Effects of brovincamine (BV) on peripheral nerves were studied in dogs and rats. 1) In pentobarbital-anesthetized dogs, BV (6.4 mg/kg) administered i.v. did not affect the changes of blood pressure and heart rate induced by noradrenaline and adrenaline, but slightly inhibited the hypotensive effect of acetylcholine. BV had no effect on the hypertension elicited by carotid sinus reflex, but diminished the bradycardia by vagus nerve stimulation. BV did not influence the tachycardia elicited by stimulation of the postganglionic nerve to stellate ganglion, but slightly inhibited that by the preganglionic stimulation. 2) In spinal dogs, BV (6.4 mg/kg) given i.v. slightly inhibited the increases of blood pressure and heart rate induced by i.v. dimethylphenylpiperazinium (DMPP). When i.v. administered in divided doses of 2 and 4 mg/kg, BV induced a slight but stepwise inhibition of the tachycardia elicited by direct administration of DMPP, bethanechol (BCH) and angiotension II (AT II) to the cardiac sympathetic ganglia via the subclavian artery. 3) In rat isolated diaphragm nerve preparations, BV at 10(-5) and 10(-4) g/ml dose-dependently reduced the twitch response to nerve stimulation. 4) In conclusion, BV does not affect the sympathetic activities but inhibits the cholinergic function in the autonomic nervous system.

Acetylcholine↗
PubMed1984

Insulin treatment and myocardial function in isolated, perfused heart from diabetic rat.

Difficulty of some patients to maintain adequate cardiac output following the termination of cardiopulmonary bypass remains a significant problem in cardiac surgery. The patients with diabetes mellitus frequently fail to respond to therapy after the cardiopulmonary bypass. However, little is known about the relationship between the control of diabetes mellitus and myocardial performance. The purpose of the present study was to look at the effect of diabetes and insulin treatment upon ventricular function and myocardial microcirculation in isolated perfused rat heart. Experimental diabetes was induced by injecting streptozotocin and some of them were treated by insulin injection. Severe form of ischemia was induced in heart from acute form of diabetes and functional recovery was compared among the control, diabetic and insulin treated groups. In chronic form of diabetes, myocardial function and microcirculation which was measured by local H2 generation method were studied during aerobic perfusion and mild form of ischemic perfusion. The hearts from experimental diabetes were more susceptible to ischemia and insulin pretreatment protected the functional alterations. This beneficial effect of insulin was associated with improved glucose and fatty acid metabolism. Myocardial microcirculation in hearts from diabetes was significantly less than in control, however, this was not correctable by the insulin treatment.

Animals↗
PubMed1984

Clinical experience of percutaneous transluminal coronary angioplasty.

PTCA (percutaneous transluminal coronary angioplasty) was performed on 44 patients with angina pectoris during the 18-month period from April 10, 1981 to September 30, 1982. It was successful in 36 of the 44 patients (82%), resulting in a subsidence of the symptoms and a considerable increase in exercise tolerance. Successful dilatations were achieved in 30 of 35 left anterior descending arteries (86%) and 7 of 11 right coronary arteries (64%). Five patients had complications: myocardial infarction in 2, unstable angina pectoris in 1, and dissection of the coronary artery in 2. One of these patients underwent an urgent A-C bypass operation. The patients were followed up for 0.5 to 18 months (average: 7.4 +/- 0.9 months). Stenosis recurred in 6 patients (16.7%), but repeat PTCA disclosed successful dilatations of stenotic lesions in 3 patients. No deaths occurred throughout the study period including the follow-up period. Our experience suggests that PTCA is of use in the treatment of certain groups of angina pectoris patients if case selection is appropriate.

Adult↗