Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CATHODE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,639 records · Page 91Linked to original sources
PubMed1985

Direct current stimulation of bone production in the horse: preliminary study with a "gap healing" model.

The effect of a 20-microA direct-current implantable bone growth stimulator (BGS) on bone production with a "gap healing" model in the horse was evaluated. The right and left 4th metatarsal bones (Mt-4) were used in 7 adult horses to create the "gap healing" model. A 4-mm section of the Mt-4 bone was resected bilaterally in each horse. The BGS was surgically placed into the 7 left Mt-4 defects. The 7 right Mt-4 defects served as controls. Six horses survived the 16-week experimental period. Signs of pain, decreased range of limb motion, or lameness was not observed in any animal during the 16 weeks. None of the animals showed complete healing radiographically. Four stimulated sites showed less periosteal reaction and 2 showed greater reaction than the 6 controls. The greatest amount of periosteal reaction or bone resorption was seen around the screws and plates in both groups. Uptakes of 99mTc-MDP in counts/pixel for control sites and stimulated sites were 7.90 and 8.25 in the "gap defect" and 5.19 and 5.06 in the areas adjacent to the gap defect. The ratio of uptake between the gap defect and adjacent area was 1.5 and 1.58 respectively. Biocompatability of the BGS was excellent; however, 1 horse had a broken cathode wire 5 cm from the generator capsule at 6 weeks. All polyethylene cathode sheaths were fluid filled at 16 weeks. The average mineralization rates were 1.57 +/- 0.34, 1.71 +/- 0.28 mm/day and bone formation activity was 0.0182 +/- 0.171, and 0.0168 +/- 0.0149 mm2/day for control limbs and stimulated limbs, respectively. There was no significant difference between groups in any of the histomorphometric values measured. Direct current (20 microA) did not increase bone production in this experiment. Methods to objectively evaluate electrically induced osteogenesis and a "gap defect" model for BGS research on the horse are discussed. The results provide a basis for additional research on electrical stimulation of fractures in the horse and for dose-response studies.

Animals↗
PubMedDate not supplied

[Immunochemical and electron microscopic analysis of the high-molecular structures in the tick-borne encephalitis virus].

High-molecular structures of tick-borne encephalitis virus were sedimented by centrifugation from virus-containing culture fluid and separated by sucrose concentration gradient centrifugation into 3 main fractions: rapidly sedimenting virions, the fraction sedimenting at a moderate rate, represented by "stellate" structures, and the fraction found on the top of the gradient and represented by structures similar in size and shape to virions, designated slowly sedimenting virions. The latter are first described in the paper. In immunodiffusion, the rapidly sedimenting virions form 1 of the 2 precipitation bands closer to the antigen-containing well, and in immunoelectrophoresis give 2 precipitation bands, anodic and cathodic, which fuse, indicating immunological identify of the 2 subpopulations of rapidly sedimenting virions. The slowly sedimenting virions in immunodiffusion form one of the 2 precipitation bands closer to the antigen well, and in immunoelectrophoresis form the cathodic precipitation band. The material sedimenting in the gradient at a moderate rate gives in immunodiffusion one precipitation band, the 3rd from the antigen well, and in immunoelectrophoresis forms a separate anodic precipitation band. This high-molecular non-virion antigen is found in small amounts also in fractions containing the rapidly sedimenting and slowly sedimenting virions. It is at least partially antigenically identical to previously studied low molecular non-virion ("soluble") antigen of tick-borne encephalitis virus.

Centrifugation, Density Gradient↗
PubMed1985

A comparative assessment of lactate dehydrogenase isozymes, LDHk and LDH5.

An apparently unique isozyme of lactate dehydrogenase has been reported associated with transformation by Kirsten sarcoma virus, which was also expressed in human cancer. This isozyme was designated LDHk (Anderson, G.R., and Kovacik, W.P., Jr., (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 3209-3213; Anderson, G. R., Kovacik, W. P., Jr., and Marotti, K. R. (1981) J. Biol. Chem. 256, 10583-10591). However, preparations of LDH5 from human placenta and from HeLa cells were later shown to exhibit some of the properties ascribed to LDHk9 and the identify of LDHk as a unique isozyme was questioned (Morin, M. E., and Hance, A. J., (1983) J. Biol. Chem. 258, 2864-2869). Saavadra and Anderson (Saavedra, R. A., and Anderson, G. R. (1983) Science (Wash. D.C.) 221, 291-292) refuted the arguments of Morin and Hance (Morin, M. E., and Hance, A. J. (1983) J. Biol. Chem. 258, 2864-2869) by claiming that commercial preparations of human placental LDH5 were contaminated with LDHk. Re-evaluation of the unique properties which distinguish LDHk from conventional LDH5 indicates that the two isozymes may not be different. Highly purified preparations of LDHk exhibit a single Mr = 34,000 polypeptide subunit on sodium dodecyl sulfate-acrylamide gels, yet retain activity detectable as both LDHk and LDH5. Attempts to separate LDHk and LDH5 by column chromatography or by continuous electrophoresis on a variety of solid support matrices were unsuccessful. Enzyme activity identified as LDHk in imidazole-borate-buffered gels migrating toward the cathode was detected as LDH5 activity on re-electrophoresis. LDH5 activity identified by electrophoretic migration toward the anode in Tris-glycine-buffered gels also recorded as LDHk when re-electrophoresed toward the cathode in imidazole-borate-buffered gels. Quantitative assays of enzyme activity recovered from the two-gel assay systems, as well as re-electrophoresis of isozyme-enriched preparations, indicated that cross-contamination of isozymes was not responsible for the results obtained.

Animals↗
PubMed1985

Appearance of osteoclasts and osteoblasts in electrically stimulated bones cultured on chorioallantoic membranes.

Tibial shafts from 15-day-old chick embryos were cultured on chorioallantoic membranes of chick embryos. These bones were stimulated by either constant-direct or constant-alternating current via platinum wire electrodes. Around the anodes of 10 microA constant direct-current stimulation, the number of osteoclasts was significantly larger than that of the control, and numerous osteoblasts were observed. Around the cathodes of this current, periosteum was thickened and accompanied by proliferation of osteoblasts. Slight bone resorption in the immediate vicinity of the cathodes was also observed. The periosteum between the two electrodes was significantly thickened by this current. The comparative study between equivalent constant direct-current and alternating-current stimulation showed a dominance of direct current. This model could be useful in investigations on electrical stimulation of bone in vivo. It produces fewer artifacts and shows activation of osteoclasts in association with activation of osteoblasts in electrically induced reactions of bone tissue.

Animals↗
PubMed1985

Development of catalytic platinum-binder electrodes for glucose determination.

Compact catalytic platinum-binder glucose sensors were developed, provided for the artificial beta-cell. These consist of three electrodes: the working electrode, a 0.5 mm diameter glass-sheathed platinum wire, covered with a mixture of platinum black and binder (PMMA, PVC) at the face, the reference electrode and the rejuvenating or counter electrode. Measurements were carried out either by a non-equilibrium method within the anodic range or by determination of the current at the anodically directed peak during the cathodic scan. In the first case a periodical switching between rejuvenating and measuring potential takes place and, in the second case, the whole voltammogram is cycled between +1.2 V and -1.2 V (vs. Ag/AgCl). For measurements in phosphate-buffered saline at 37 degrees C the calibration curves exhibit an approximately linear dependence up to a glucose concentration of 30 mM; the sensitivity amounts to 0.3 microA mM-1 and the response times t90% are between 6 and 10 min. A urea concentration of 2.5 mM causes a decrease of the non-equilibrium current of 11.5%-3.0%, and a mixture of amino acids causes a current rise of 11.4%-2.7% with increasing glucose concentration. During the cathodic scan the amino acids affect the peak current negligibly, and the influence of urea reaches saturation for concentrations higher than 6.7 mM. Preliminary in vivo measurements permit the conclusions that after appropriate pretreatment the catalytic glucose sensors can be used for short-time blood glucose monitoring.

Animals↗
PubMed1979

Creatine kinase isoenzymes of mitochondrial origin in human serum.

We measured creatine kinase (EC 2.7.3.2) activity in 1009 serum samples from 538 patients in the intensive-care units of the University of Texas Medical Branch hospitals. Creatine kinase isoenzymes migrating cathodal to skeletal muscle creatine kinase (CK-MM) on cellulose acetate electrophoresis were found in sera from 14 of the 538 patients. Creatine kinase, lactate dehydrogenase (EC 1.1.1.27), aspartate aminotransferase (EC 2.6.1.1), and alanine aminotransferase (EC 2.6.1.2) activities were abnormally increased in these 14 patients. Liver lactate dehydrogenase isoenzyme (LDH5) and cardiac creatine kinase isoenzyme (CK-MB) were abnormally increased in 12 and eight of these patients, respectively. Ten of the 14 patients died during their hospital admission. We believe the creatine kinase isoenzymes that migrated cathodal to skeletal muscle creatine kinase (CK-MM) were of mitochondrial origin.

Adolescent↗
PubMed1977

Determination of pancreatic elastase with new chromogenic substrates-p-nitroanilides of N-acyltripeptides.

Mal-, Suc- and Glt-(Ala)3-NAp were prepared as new substances for determining pancreatic elastase. The kinetic constants show them to be more satisfactory than the previously described Ac-(Ala)3-NAp. The mean elastase output values after pancreozymin and secretin stimulation of the exocrine pancreas were significantly higher in the control subjects than in patients in whom other secretion values were altered. In agar electrophoresis, hog pancreatic elastase (Merck) formed a single cathodal fraction. One cathodal and one anodal fraction were found in human duodenal contents. Serum, plasma, alpha1-antitrypsin and alpha2-macroglobulin inhibit pancreatic elastase. Elastase-alpha1-antitrypsin complexes are enzymatically inactive, whereas the enzymatic activity of elastic-alpha2-macroglobulin complexes is partly preserved. Both types of complexes are stable and are not dissociated to a major extent in the presence of an excess amount of the other inhibitor.

Anilides↗
PubMed1978

Effect of ionizing radiation of the antigenic composition of typhoid bacteria.

Changes in the antigenic composition of typhoid bacteria occurring during the exposure of microbial suspension to different doses of gamma irradiation [Co60] ranging between 0.5 and 3.0 Mrad were studied. Immunoelectrophoresis in agar was used to determine the antigenic composition of different samples of irradiated bacteria. The antigenic composition of bacteria irradiated with doses up to 2.5 Mrad was found to be similar to that of non-irradiated bacteria. Antigens demonstrated by means of Vi, H and O ontisera are preserved in these bacteria. However, all irradiated bacteria in general slightly differ from non-irradiated bacteria; this is manifest in a different configuration and position of the precipitation lines in the cathodic part of the immunophoreograms. The content of the component migrating rapidly towards the cathode, evidently the O antigen in the R form, in the irradiated bacteria increases with the dose of radiation. No new serologically active substances, non-existent in non-irradiated bacteria, were found to appear in the process of irradiation.

Antigens, Bacterial↗
PubMed1977

Preparation (agar zone electrophoresis) and immunological characterisation of urokinase.

Urokinase was highly purified by electrophoretical and immunological methods starting with a commercial urokinase preparation (UK-Leo). Contaminating serum proteins and enzyme activities migrated into opposite directions in agar gel electrophoresis which proved to be a valuable preparative method. The final purification achieved was 80,000 Ploug units/mg protein. Traces of albumin, alpha2HS-glycoprotein and alpha2-macroglobulin migrated towards the cathode together with UK in a multimolecular complex. Urokinase antibodies (rabbit) gave with the cathodic fraction 2 precipitation lines (Ouchterlony technique): the one precipitation line corresponded to urokinase (molecular weight on gel chromatography 32,000 daltons), the other corresponded to UK complexed with serum proteins. Urokinase antibodies completely suppressed UK activity in various commercial preparations. All these preparations showed immunological identity; on disc electrophoresis pure urokinase (32,000 daltons, 80,000 Ploug units/mg protein) still gave 2--3 bands suggesting the presence of isoenzymes.

Antigen-Antibody Reactions↗
PubMed1975

[Effect of noradrenaline on the electrical and contractile properties of smooth muscle cells in the pulmonary artery].

Experiments were performed on the smooth muscle cells of rabbit a. pulmonalis using the microelectrode technique. No spontaneous electrical or mechanical activity was recorded in normal Krebs solution. The current-voltage relation in these smooth muscle cells showed marked rectification. No changes in the isometric tension were observed due to the anodal or cathodal stimulating currents. Strong depolarization of the muscle cells produced only local potentials on the cathelectrotone which never developed into a spike. Noradrenaline (10(-8) g/ml) caused depolarization of the 5-7 mV in the muscle cell membrane and a considerable contraction of the muscle strip as well. Under such conditions the contractile apparatus of the muscle cells became sensible to the resting potential level. Anodal stimulation was accompanied by relaxation of the muscle strip, whereas cathodal stimulation--by its contraction. The alpha-adrenoblocking agent (phentolamine) blocked the effect of noradrenaline evidencing the fact that noradrenaline exerted its excitatory action on the smooth muscle cells of the a. pulmonalis through the alpha-adrenoreceptors.

Adrenergic alpha-Antagonists↗
PubMed1983

Subcellular distribution of inorganic pyrophosphatase activity in various normal and neoplastic cell types.

Inorganic pyrophosphatase (PPiase) activity was measured in cell fractions of rat, mouse, and human erythrocytes; normal rat liver; Novikoff hepatoma; Morris 3924A hepatoma; and mouse Ehrlich and Sarcoma 37 ascites tumors. Despite high intracellular activities, when precautions were taken to maintain cell integrity, only negligible activities were found on the surface of intact erythrocytes, Novikoff ascites hepatoma, Ehrlich carcinoma, and Sarcoma 37 cells. Suspensions of intact Ehrlich and Sarcoma 37 cells exhibited low PPiase activity, but this was only about 1 to 2% of the intracellular activity and was completely accounted for by activity present in the suspension medium. It is considered to be due to extrusion of the intracellular enzyme. Systematic fractionation of subcellular components revealed that 92% of the total PPiase activity of rat liver and 97.5% of that of Hepatoma 3924A were in the cytosol. The soluble activity consisted of a major form, accompanied by very low activities of two minor forms, all of which migrate toward the anode on electrophoresis. About 4.5% of the liver activity was present in the mitochondria in two forms, one remaining at the origin and one migrating toward the cathode. The same cytosolic isozymes were present in Hepatoma 3924A, and the cathodic form was present in mitochondria but in much reduced amount. No evidence was obtained for specific isozymes in nuclei or microsomes. Only negligible PPiase activities were found in cell membranes isolated by sucrose gradient centrifugation. These results discount the occurrence of PPiase activity as an ectoenzyme or in the plasma membrane of these cells and point to the cytosol as the major and mitochondria as a minor locus of intracellular PPiase activity.

Animals↗
PubMed1984

Serotypes of red clover necrotic mosaic virus. III. Immunoelectrophoresis under different conditions.

The effects of 4 buffers at different pH and of different molarities was tested on the immunoelectrophoresis of representatives of three serotypes and their natural mixtures of red clover necrotic mosaic virus (RCNMV). No substantial differences were observed with buffers at pH 7.2, 8.0 and 8.6. The representatives of the three RCNMV serotypes showed different mobilities in 0.1 and 0.01 mol/l ionic buffers in the agarose gel from cathode to anode. In nonionic 0.01-0.1 mol/l N-2-hydroxyethylpiperazine-N'-ethanesulphonic acid (HEPES) buffer, the RCNMV isolates moved from the anode to the cathode. Isolate TpM48 (serotype B) moved the most rapidly, while isolates No. 6 (serotype C) and TpM34 (serotype A) showed lower mobilities distinct from one another. This made possible a reliable differentiation of serotype B from serotypes A and C as well as of serotype A from serotype C. Agarose gels in 0.001 mol/l buffers proved to be unsuitable for the immunoelectrophoresis of RCNMV.

Hydrogen-Ion Concentration↗
PubMed1980

Isoamylases in clinically normal dogs.

Isoenzymes of canine serum amylase were evaluated by electrophoresis on cellulose acetate membranes in a discontinuous buffer system. Two isoamylase groups were identified in the serum of clinically normal dogs. Most of the serum amylase activity was the more cathodal isoamylase. The anodal isoamylase was rarely observed in serum from normal dogs and, when present, accounted for little of the enzymatic activity. Amylase activities of various tissues were determined and isoenzymes were identified. The anodal isoenzyme was found in the pancreas and uterus. The cathodal isoamylase had its origin mainly from the intestinal tract. Activities of other tissues were not greater than was serum amylase activity. Effects of feeding upon total serum amylase activity and isoenzyme composition also were examined over a period of 5 minutes to 7 hours. Feeding did not markedly alter the serum amylase activity.

Amylases↗
PubMed1978

[Changes in lactate dehydrogenase isoforms in the process of oncogenesis].

Isoenzymes of lactate dehydrogenase were studied by disc-electrophoresis in polyacrylamide gel, and in the clinic--in 1% agar gel. Oncovirus A12 invasion of the culture of rat embryo fibroblasts (REF) was found to result in the increased percentage of the cathode fractions activity (LDG-4 and LD-5) and in the disappearance of LDG-1 yet during the first day of the experiment prior to hypoxia and enhanced proliferation, i. e. it is most likely to be primary. In the homogenates of cancerous tumor and large intestine polyps of man also a reliable increase of the cathode and a decrease or disappearance of the anode fractions accur. A correlation of the experimental and clinical data allowed a suggestion to be made that LDG isoenzymes changes are genetically conditioned and play an important role in the process of oncogenesis, providing conditions for the increased intensity of glycolysis and proliferation.

Adenoviruses, Human↗
PubMed1983

Electrode-oxygen consumption and its effects on tissue-oxygen tension. A study by mass spectrometry.

A theory for the mechanism of electrical bone stimulation proposes that passage of an electric current reduces the local PO2 and raises the pH near the cathode, thereby creating a favorable environment for osteogenesis. To study the effects of electric current passage on the PO2, PCO2 and pH in the vicinity of the electrodes in vivo, a wire electrode spiralled around the catheter of a clinical mass spectrometer was placed in dog muscle. Electrodes were made of stainless steel or platinum. With a cathode located in the tissue, a 20-microA direct constant current caused a drop in PO2 of 5-10 mmHg and a drop in PCO2 of 2-6 mmHg, both reaching plateaus again within five to 20 minutes. The time required to reach this new equilibrium was shorter for platinum than for stainless steel. When the electric current was turned off, PO2 and PCO2 reversed to their original values. Because of the high buffer capacity of tissue, it is highly unlikely that 20-microA current would induce a change in pH.

Animals↗
PubMed1978

Iontophoresis of vidarabine monophosphate into rabbit eyes.

In order to investigate the efficacy of iontophoresis for increasing the penetration of vidarabine monophosphate into the eye, tritium-labeled vidarabine monophosphate was applied to rabbit eyes by topical and iontophoretic application, and the penetration of the compound into the eye, and its subsequent metabolism, were studied. At 20 min after treatment, the ratios of radioactivity for cathodal iontophoresis compared to topical application alone were cornea 8.6, aqueous humor 4.8, and iris 2.4; for 60 min the ratios were cornea 12.2 aqueous humor 17.5 and iris 2.5. In addition, the acid-soluble components were extracted from the cornea and aqueous humor. Vidarabine monophosphate, vidarabine, hypoxanthine arabinoside, adenosine, hypoxanthine, and adenine from the acid-soluble fraction were separated by thin-layer chromatography. The amount of vidarabine monophosphate and vidarabine in the cornea and aqueous humor from the iontophoretically treated group was six to 15 times higher than from the group that received topical application of the drug. It was concluded that cathodal iontophoresis resulted in significantly increased penetration of the antiviral drug vidarabine monophosphate into the anterior chamber of the eye. The effects of iontophoresis of vidarabine monophosphate on corneal epithelium, as observed by scanning electron micrographs, were equal to or less than those seen with the topical application of widely used preservatives in ophthalmic preparations.

Adenine↗
PubMed1983

A transparent transcutaneous oxygen electrode for simultaneous studies of skin capillary morphology, flow dynamics and oxygenation.

Transcutaneous PO2 (tcPO2) measurements have become a standard method for a monitoring arterial PO2 of patients with cardio-respiratory problems. Direct heating of a silver/silverchloride anode induces a local hyperemia of the skin, which permits measurements of PO2 on the skin surface polarographically. This technique has been applied recently to quantify skin variability in peripheral arterial occlusive disease, to predict the optimal amputation level or skin transplant survival. However, so far local capillary morphology could not be correlated to tcPO2 data. The purpose of the newly developed electrode was to abolish this disadvantage and to be able to correlate capillary morphology and distribution to local tcPO2 by means of videomicroscopy or dynamic fluorescence videomicroscopy. The middle part of the new electrode consists of a glass cylinder (diameter 4.5 mm) and only one 15 micron Platinum cathode, which provides a negligible O2-consumption of the electrode itself (approx. 5.5 x 10(-3) mmHg/min). The careful optical grinding of the glass cylinder gives a good transparency for observing the capillaries through the incident light microscope of the videomicroscopy system. The electrode is covered by a 25 micron Teflon membrane, which also constitutes no essential optical barrier. By focusing at the tip of the Platinum cathode and the adjacent capillaries the distance between both objects or the intercapillary distance can be measured. The new combined system of transcutaneous PO2 measurements and simultaneous videomicroscopy has great potential as a practical method to provide new insights into local skin oxygen supply and the local microcirculatory flow distribution and capillary morphology.

Capillaries↗
PubMed1980

Differential quantification of SIgA and SC by two-directional rocket method.

The two-directional rocket method, a newly modified method for quantitative immunoelectrophoresis, was used as the assay for separating SC and SIgA, which have identical antigenicity but differ in mobility. This method proved to be sufficiently simple and sensitive to enable simultaneous assay of SC and SIgA in saliva. The method employs electrophoresis into antibody-containing agarose/agar gel in the presence of heparin-Ca EDTA. The height of the precipitation peaks formed in two directions is proportional to the concentration of the antigens. Concomitant use of agarose which has little electroendosmosis and agar which has high electroendosmosis facilitated cathodic migration of SIgA. Transfer of SC from beta-region to alpha 1-region without influencing the mobilities of SIgA, albumin or IgG was obtained by addition of heparin-Ca EDTA to agarose/agar gel. This effect of heparin-Ca EDTA is vulnerable to changes of pH of the gel, but is almost completely independent of change in composition or concentration of the gel. The function of heparin as a polyanion may be resonsible for it. Carbamylation of antibody was used to accelerate a clear-cut resolution of the cathodic rockets. This technique was found to be a method of choice for analysis of SIgA and SC in large numbers. In using this method as a screening assay for detection of primary immunodeficiency, by studying saliva samples collected from 3 month old infants on the occasion of regular check-up over a 2 year period, two cases of isolated IgA immunodeficiency and two cases of hypoglobulinaemia were discovered in 12,000 infants.

Agar↗