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PubMed2001

Motor and sensory conduction velocities and amplitude of nerve or muscle potentials in the normal rat according to age.

The relative changes in sensory and motor nerve conductions and SNAP and CMAP amplitudes were studied on the sural and tibial posterior nerves in anesthetized male rats, between the 1st and the 23rd month. Neural growth was controlled with the measure of the nerve path length on the skin, between stimulating and recording cathodes for the sural nerve and proximal and distal stimulating cathodes for the tibial posterior nerve. The sural SCV and SNAP amplitude are consistent with a more accurate method than the H-reflex one. Similar changes were observed in both parameters. During the maturation of the peripheral nervous system, between the 1st and the 5th month, parameters rapidly increased. Over 14 months old, parameters decrease: the diminution of SNAP and CMAP amplitudes is characteristic of aging. The results were analyzed through quadratic and linear regression and were similar to those in young and elderly human patients. Parabola curves fitted the best way to represent the evolution of parameters. Moreover, the linear regression permitted to divide the rat life in 3 parts and to distinguish a period between the 6th and 13th months during which studied parameters are considered as constant. SCV, MCV, SNAP and CMAP amplitudes from the 1st to the 5th, from 6th to 13th and over the 14th month, could be used as reference.

Action Potentials↗
PubMed1976

Comparison of the redox bioassay with other assays for luteinizing hormone.

The cytochemical (redox) bioassay for LH has been compared with established LH assays. Measurements made by redox bioassays were considerably lower than those made by radioimmunoassay in human female plasma samples obtained at mid-cycle. There was no apparent relationship between measurements on incubation media from cultures of sheep pituitary glands made by redox bioassay and the ovarian ascorbic acid depletion (OAAD) assay. After polyacrylamide gel electrophoresis of a crude extract of a human pituitary gland, redox LH measurements were lower than those of the OAAD assay and radioimmunoassay in the cathodal segments of the gel. By contrast, there was reasonable agreement between LH measurements made by radioimmunoassay and redox assay in cathodal fractions from gel electrophroesis of a purified pituitary LH preparation. Follicle-stimulating hormone, and the alpha- and beta-subunits of LH depressed the response of intact LH in the redox assay; this might explain the relatively low levels of LH measured by redox assay in some of the experiments described. Which type of assay best reflects the biological activity of LH in man remains to be determined.

Animals↗
PubMed2007

Carbon felt-based bioelectrocatalytic flow detectors: highly sensitive amperometric determination of hydrogen peroxide using adsorbed peroxidase and thionine.

Horseradish peroxidase (HRP) and thionine (TN) were co-adsorbed onto a porous carbon felt (CF), and the resulting HRP and TN-adsorbed CF (HRP-TN-CF) was successfully used as a working electrode unit of a novel bioelectrocatalytic flow detector for a highly sensitive amperometric determination of hydrogen peroxide (H(2)O(2)). Co-adsorbed TN was essential to enhance the cathodic peak current of H(2)O(2), and the current responses of the HRP-TN-CF-based detector were much larger than those of the HRP-CF-based detector (without TN). When air-saturated 0.1 M phosphate buffer (pH 7.0) was used as a carrier at a flow rate of 3.9 ml/min, cathodic peak currents of H(2)O(2) (sample injection volume, 200 microl) obtained at an applied potential of 0 V (vs. Ag/AgCl) increased linearly up to 50 microM with a detection limit of 0.1 microM. Repetitive 100 sample injection of 100 microM H(2)O(2) induced no serious current decrease, and RSD was 0.41 to 1.21% (n = 100). The HRP-TN-CF retained 42% of its original activity after 8 days of storage in 0.1 M phosphate buffer at 4 degrees C.

Adsorption↗
PubMed2005

Reductive dechlorination of tetrachloroethene in a sand reactor using a potentiostat.

In this study, an electrochemical system was investigated to enhance abiotic dechlorination of chlorinated solvents in contaminated soil in situ. A potentiostatic electrolysis sand reactor was developed and tested to evaluate tetrachloroethene (PCE) dechlorination in saturated sand. When operated with recirculating nutrient-supplemented water the reactor sustained a low oxidation reduction potential (ORP) at the cathode (<-400 mV standard hydrogen electrode [SHE]), a pH less than 9.4, and electric current >5 mA at room temperature with the cathodic potential controlled at -950 mV SHE. Tetrachloroethene in the electrolysis reactor had a half-life of 6.8 d compared with the control bioreactor without electrolysis, which had a PCE half-life of 16.4 d. Ethane and ethene were the main dechlorination products in the test reactor, while trichloroethene (TCE) accumulated in the nutrient-amended control reactor without electrolysis. An electrolysis reactor operated with water not amended with nutrients showed a PCE half-life of 7.6 d, suggesting that most of dechlorination activity in the reactor was abiotic. Since complete dechlorination can be achieved under moderate pH and temperature, this type of electrolysis technology is attractive as a remedial method for subsurface chloroethene contamination.

Bioreactors↗
PubMed2006

The effect of Fe(0) on electrokinetic remediation of clay contaminated with perchloroethylene.

The present paper was to investigate the effect of Fe(0) reaction barrier position and Fe(0) quantity on the remediation efficiency and electrokinetic performances of tetrachloroethylene (PCE) contaminated clay under potential gradient of 2 V/cm for 5 days. The Fe(0) reaction barrier was composed of 2 to approximately 16 g of Fe(0) mixed with Ottawa sand in a ratio of 1: 2. Its positions were respectively located at the anode, the middle, and the cathode end of the electrokinetic cell. Results showed that a relatively higher remediation of 66% of PCE was found as the Fe(0) reaction barrier located at the cathode side, which corresponded to a factor 2.4 times greater than that in the EK system alone (27.0%). As the Fe(0) quantity increased to 16 g, a highest remediation efficiency of 90.7% was found. It was concluded that the PCE removal in the EK/Fe(0) system was dominated by Fe(0) quantity rather than the Fe(0) reaction barrier position. As more Fe(0) existed in the EK system, a higher electroosmosis flow, higher permeability, and lower soil pH after treatment were found. The cost analyses were also investigated in this research.

Aluminum Silicates↗
PubMed1990

[Experimental study on the application of direct current to the intra-osseous implant].

The purpose of this study is to investigate the effect of the direct current electrical stimulation on surrounding tissue of the intra-osseous implant. The implant was composed of a peripheral hydroxyapatite layer and a central metal which was used as electrodes, and applied 10 microA constant direct current. They were implanted in femurs of four guinea pigs. These results were as follows: 1. When the bone marrow is stimulated electrically with 10 microA direct current for 28 days, large amount of bone formation around the implant was seen in wide area. 2. There was a different reaction surrounding tissue between cathode and anode. Around the cathode, bone formation on the surface of the implant was recognized remarkably. Around the anode, little amount of bone formation on the surface of the implant was recognized. 3. The electrical stimulation, with newly developed power unit and electrode, accelerated new bone formation.

Animals↗
PubMed1990

[Analysis of protein band pattern in gingival crevicular fluid. Character and clinical comparison between healthy subjects and periodontal disease patients].

We have been studied the characteristics of protein components in gingival crevicular fluid (GCF) with isoelectric focusing technique. The purpose of this study was to investigate the relationship between those proteins and clinical findings such as Gingival Index (Loe & Sillness), Pocket depth, Plaque Index (Quigley & Hein), Gingival Bleeding Index and Bone Index. GCF, serum and mixed saliva collected from the same subject were analyzed, and following results were obtained. The patterns of protein bands in GCF were similar to those in serum but different from mixed saliva, and the pI of main protein band of GCF and serum were 4.9. No apparent difference was observed on the patterns between clinically healthy gingiva and those received periodontal disease. Protein patterns were compared with the before mentioned clinical findings and GCF volume. Main protein bands were observed on cathode side (pI 8.0-9.0) at the patterns against Gingival Index: 0-1 or greater than 2, Gingival Bleeding Index: + or -, Pocket Depth: 0-1 or greater than 2 and Bone Index: 1 or greater than 3. It was suggested that the study of the proteins on cathode side is important.

Gingival Crevicular Fluid↗
PubMed2000

Regional anesthesia of the infraorbital and inferior alveolar nerves during noninvasive tooth pulp stimulation in halothane-anesthetized cats.

OBJECTIVE: To determine whether anesthesia of the infraorbital and inferior alveolar nerves abolishes reflex-evoked muscle action potentials (REMP) during tooth-pulp stimulation in halothane-anesthetized cats. ANIMALS: 8 healthy adult cats. PROCEDURE: In halothane-anesthetized cats, an anodal electrode was attached to the tooth to be stimulated and a platinum needle cathodal electrode was inserted in adjacent gingival mucosa. Cathodal and anodal electrodes were moved to the upper and lower canine, upper fourth premolar, and lower first molar teeth for stimulation; baseline REMP was recorded. A 25-gauge 1-cm needle was inserted 0.5 cm into the infraorbital canal. A 25-gauge 1-cm needle was inserted 1 cm rostral to the angular process of the ramus, and advanced 0.5 cm along the medial aspect. Chloroprocaine was injected at each site. Each tooth was stimulated every 10 minutes for 90 minutes. RESULTS: REMP was abolished within 10 minutes for all upper teeth, except for the upper canine tooth in 1 cat, and abolished within 10 minutes for lower teeth in 4 cats. In 1 cat, REMP was not abolished in the lower first molar tooth. In 3 cats, REMP was not abolished in the lower canine and first molar teeth. At 90 minutes, REMP was restored for all teeth except the lower canine tooth in 1 cat, for which REMP was restored at 120 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Regional anesthesia of the infraorbital and inferior alveolar nerves may provide dental analgesia in cats.

Anesthesia, Conduction↗
PubMed2001

Aversive and attractive properties of electrical stimulation for Paramecium caudatum.

Although there are data to show that mild electrical stimulation from a cathode source can serve as positive or attractive stimulus for paramecia, the properties of anode stimulation have not been clear. This research gives evidence to support the previously reported positive properties of cathode stimulation but showed that anode stimulation has opposite (negative or aversive) properties.

Animals↗
PubMed1979

Agarose gel electrophoresis of duodenal juice in normal condition and in children with malabsorption.

Agarose gel electrophoresis (at pH 8.6) was used for qualitative determination of pancreatic enzymes in duodenal juice. The various enzymes were identified by staining techniques with specific chromogenic substrates, by quantitative determination of enzymes in eluates of gel slices, and by immunoelectrophoresis. The various protein bands corresponded to the following enzymes (from the anode to the cathode): chymotrypsin, trypsin, carboxypeptidase A, chymotrypsin, amylase (around the slit), lipase, elastase, and trypsin. The method was applied to a study of exocrine pancreatic function in 10 adults and 83 children suspected of having malabsorption. The duodenal juice, also analyzed for trypsin and amylase content, was collected in fasting condition and after a test meal of water. In patients with normal pancreatic function, all the enzyme bands were present and easy to recognize. In 87 patients carboxypeptidase A was present as two bands in 68 (80%), anodal trypsin as two bands in 39 (45%), and cathodal trypsin as two bands in 85 (97%). Electrophoresis of duodenal juice gave as much information from the fasting sample as after the test meal. Six children with pancreatic insufficiency (cystic fibrosis and Shwachmar's syndrome) had no or only faintly stained enzyme bands and a strongly stained albumin-containing band most anodally. The method is simple, rapid, and useful in routine work. The combination of this qualitative test with a quantitative one (e.g. trypsin determination) provides good information about exocrine pancreatic function.

Adolescent↗
PubMed1991

In vitro vs in vivo corrosion analyses of two alloys.

The in vitro and in vivo corrosion characteristics of two alloys, cast Co-Cr-Mo (ASTM F75) and wrought Ni-Cr-Mo, were evaluated using electro-chemical corrosion analysis. Two in vitro electrolytic solutions were utilized, an isotonic saline solution consisting of 0.9 w/o NaCl in distilled water and an isotonic saline solution with 10 v/o sterile calf serum. The in vivo environment was created by implanting cylindrically shaped specimens of each alloy into the back muscles of New Zealand white rabbits. Cyclic anodic and cathodic polarization curves were generated for the three test conditions and subsequently were compared. Anodic curves conducted using the isotonic saline and isotonic saline plus serum electrolyte solutions were very similar to the anodic curves generated for the implanted alloy specimens for both alloys. The corrosion rates predicted from the in vitro and in vivo cathodic polarization curves were not statistically different for the three test conditions. Overall, the corrosion data generated using the in vitro environmental conditions adequately predicted the in vivo corrosion behavior of the cast Co-Cr-Mo and wrought Ni-Cr-Mo alloys.

Animals↗
PubMed1991

Slowly adapting cutaneous mechanoreceptor afferent units associated with Merkel cells in frogs and effects of direct currents.

In the bullfrog, two types of slowly adapting (SA) cutaneous mechanoreceptor afferent units have been identified physiologically: irregularly discharging frog type I (Ft I) units in both warty and nonwarty skin, and regularly discharging frog type II (Ft II) units in the nonwarty skin. In the present study, mechanosensitive spots of Ft I units were located around the skin warts in the warty skin. The quinacrine technique (Crowe and Whitear, 1978) revealed that quinacrine-accumulating Merkel cells were present around the skin warts and near the orifice of skin glands that also surrounded the skin warts. Thus, a significant correlation was found between the location of Merkel cells and the receptive fields (RFs) of Ft I units in the warty skin. Direct current (DC) stimulation was applied for 1 sec to the skin inside and outside the mechanical RFs of the two types of SA units. RFs for DC stimulation were located on those for mechanical stimulation in both types of SA units. The current threshold required to produce a single spike was lower in cathodal than in anodal pulses in both types of SA units. Greater current intensity elicited an increased number of spikes, but the effective polarity of currents was anodal for Ft I units and cathodal for Ft II units. The optimal current intensity for producing prolonged discharges ranged from +60 to +100 microA in Ft I units and - from -50 to -80 microA in Ft II units. The sequence of impulses evoked was irregular in Ft I units and regular in Ft II units, as seen in mechanical responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Radical intermediates in the redox reactions of tetrazolium salts in aprotic solvents (cyclovoltammetric, EPR and UV-VIS study).

Tetrazolium Blue (TBCl2) and Nitrotetrazolium Blue (NTBCl2) cathodically reduced in non aqueous solvents form radicals with the center of unpaired electron on the tetrazolyl ring (TBH., NTBH.) as detected by EPR spectroscopy. After prolonged reduction, formazans (TBH2, NTBH2) are formed and are then further reduced to the nitro-centered anion radical (from NTBH2) and the azogroup-centered anion radical (from TBH2). The first cathodic peak in the cyclovoltammetric study in the region from -0.3 to -0.6 V vs. SCE (saturated calomel electrode) is irreversible and indicates an adsorption and diffusion process on the platinum and mercury electrodes. Formation of TBH+ and NTBH+ is assumed. The second peak, in the region from -0.8 to -1.3 V vs. SCE, is nearly reversible and coupled with the formation of TBH. and NTBH. radicals. UV-VIS spectra measured during the reduction show isosbestic points at the conversions: TB++-->TBH+, NTB++-->NTBH+; further, TBH+-->TBH2 and NTBH+-->NTBH2. The characteristic colours of the solutions observed can be used to characterise the reduction state of tetrazolium salts.

Electrochemistry↗
PubMed1992

Short-term effect of guided bone regeneration and electrical stimulation on bone growth in a surgically modelled resorbed dog mandibular ridge.

This study compares the quantitative bone changes that occur in attempting to augment a resorbed mandibular ridge by electrical stimulation and by the guided bone regeneration technique. At the base line three defects resembling an atrophic ridge were created in the mandible of 5 beagle dogs. Concomitantly, a constant current generator producing 20 +/- 2 mA was implanted under the floor of the mouth. Six weeks later a titanium cathode was inserted in the first bony defect and connected to the generator (electrical stimulation = ES); another titanium cathode, not connected to the generator, was inserted in the second defect (non-electrical stimulation = non-ES); the third defect remained without an electrical device (membrane only = MO). All 3 defects were covered with an expanded polytetrafluorethylene membrane, so as to prevent soft tissue proliferation into the defects. Tetracycline bone labelling compounds were administered to mark new bone formation. Four weeks following stimulation, ground sections were prepared for fluorescent microscopy. Differences between ES vs MO and between non-ES vs MO mean scores were statistically significant, indicating that 4 weeks of electrical stimulation resulted in similar bone formation as with non- electrical stimulation when both are confined to a membrane isolated defects.

Animals↗
PubMed1982

The effect of transistor-regulated direct current on non-fractured rabbit femur.

An experienced study was performed to examine the effects of transistor-regulated 20 microampère direct current on rabbit femur and to evaluate methods of measuring the effects. The anode and the cathode were both placed in drill holes in the anterior aspect of the cortex of the right femur, the left femur being used as a control with the electrodes without current. The effects of the electrical stimulation were evaluated by means of roentgenograms, photomorphometric measurements of the cortical width and measurements of bone volume, ash-weight and 85Sr uptake. In the roentgenograms it could be seen that osteogenesis was induced both at the anode and the cathode. Also, an increased uptake of 85Sr was demonstrated indicating an increased bone formation rate.

Animals↗
PubMed2004

Deep brain stimulation for the treatment of parkinsonian, essential, and poststroke tremor: a suitable stimulation method and changes in effective stimulation intensity.

OBJECT: The tremor-suppression effect resulting from long-term stimulation of the thalamic nucleus ventralis intermedius (Vim) and the nucleus ventralis oralis posterior (Vop) was examined in the treatment of parkinsonian, essential, and poststroke tremor. METHODS: After identifying the accurate anterior border of the nucleus ventrocaudalis (Vc), deep brain stimulation (DBS) electrodes with four contacts were inserted into the Vim-Vop region at an angle of between 40 and 50 degrees from the horizontal plane of the anterior commissure-posterior commissure line. Two distal contacts were placed on the Vim side and two proximal contacts on the Vop side. The best sites of stimulation and parameters of bipolar stimulation were selected in each case and follow-up examinations were conducted for at least 2 years. In all 15 cases of parkinsonian tremor (18 sides) and in 14 of 15 cases of essential tremor (24 of 25 sides), cathodal stimulation of the Vim side with anodal stimulation of the Vop side was determined to be the best choice to suppress the tremor. In poststroke tremor, however, six of 12 cases (six of 12 sides) were selected for cathodal stimulation of the Vop side with anodal stimulation of the Vim side. The average stimulation intensity 1 month after initiation of DBS was 1.61 V in cases of parkinsonian tremor, 1.99 V in cases of essential tremor, and 2.39 V in cases of poststroke tremor. A comparison of stimulation intensities required at 1 and 24 months after initiation of DBS revealed that the lowest effective stimulation intensity increased 24.2% in cases of parkinsonian tremor, 21% in cases of poststroke tremor, and 46.9% in cases of essential tremor. Suppression of tremor was achieved in all cases (42 cases, 55 sides) during a period of 2 years. Nevertheless, two cases of poststroke tremor required dual-lead stimulation at the unilateral Vim-Vop region from the start of DBS, and two cases of essential tremor and one case of poststroke tremor required a stimulation intensity that was high enough to evoke unpleasant paresthesia and slight motor contraction during the follow-up period. CONCLUSIONS: Effective stimulation sites and stimulation intensities differ in different kinds of tremor; Vim and Vop stimulation is necessary in many cases. Interactions of the Vim and Vop under the control of interconnected areas of the motor circuitry may play an important role in both the development and DBS-induced suppression of tremor.

Adult↗
PubMed1998

Electrosyntheses from aromatic aldehydes in a flow cell. Part I. The reduction of benzaldehyde.

The reduction of benzaldehyde in acidic water-methanol mixtures has been re-investigated in a membrane flow cell with a lead cathode with the objective of defining conditions where le- reduction occurs and the C6H5CH.OH radical intermediate is formed in high selectivity. It is shown that it is the cathode potential which controls the ratio of le-/2e- product (i.e. hydrobenzoin to benzyl alcohol) and a high rate generation of the radicals is also favoured by an efficient mass transport regime.

Benzaldehydes↗
PubMed1979

The binding of streptomycin to ribonucleotides.

Incubation of streptomycin (SM) with [32P]5'-ribonucleotides at pH 7.0 produces fractions that migrate towards the cathode in high voltage electrophoresis (HVE) separations at pH 3.5. SM appears to interact with pG, pA and pC but not with pU. The appearance of these [32P]-labeled fractions is dependent on incubation time and SM concentration. Incubation of nucleotides with dihydrostreptomycin (DSM) or SM reduced with sodium cyanoborohydride (NaBH3CN) at pH 5.0, does not produce detectable changes in [32P] nucleotide mobility on HVE; however, incubation with SM reduced with NaBH3CN at pH 7.0 does produce [32P]-labeled fractions migrating with a net positive charge. Elution of [32P]-labeled material migrating towards the cathode from SM-5'-nucleotide incubations and re-electrophoresis results in nucleotides migrating with pG, pA and pC markers. These data indicate a reversible interaction between the SM-streptose aldehyde and amino-group containing nucleotides. This type of interaction may form an additional binding site for SM to RNA, relative to DSM.

Chemical Phenomena↗