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PubMed1981

Relationship between membrane potential and calcium ion fluxes in the fragmented sarcoplasmic reticulum.

The relation between membrane potential and Ca2+ fluxes in the skeletal fragmented sarcoplasmic reticulum (FSR) was investigated using cyanine dye (diS-C3-(5) as a potential probe. Change of membrane potential and Ca2+ release from FSR were induced by changing the ionic composition of the medium. When the medium was changed from K-gluconate to Tris-gluconate, a large fluorescence intensity change was observed, while no Ca2+ release occurred. On the other hand, when the medium was changed from K-gluconate to KCl, Ca2+ release occurred notwithstanding a relatively small fluorescence intensity change. This KCl-induced Ca2+ release from FSR was inhibited by the addition of sucrose. Also, the presence of both permeable anion and cation was required for induction of Ca2+ release. These results suggest that there is no correlation between "depolarization" and Ca2+ release. Ca2+ uptake by FSR created the positive-inside potential which was reversed by the application of Ca2+ ionophore A23187. The addition of valinomycin or nigericin, and the replacement of Cl- with gluconate-affected potential formation. These facts suggest that Ca2+ uptake is accompanied by K+ efflux and/or Cl- influx for partial compensation of the change.

Animals↗
PubMedDate not supplied

Antitumor activity of calcium in combination with antitumor agents against Lewis lung carcinoma.

The antitumor activity of calcium gluconate in combination with mitomycin C and 5-fluorouracil was examined against subcutaneously implanted Lewis lung carcinoma-bearing C57BL/6 mice. The mice were divided into four groups: group 1 received mitomycin C (2 mg/kg) and 5-fluorouracil (50 mg/kg) intraperitoneally once a week for four weeks beginning from the day after implantation of tumors, as well as calcium gluconate (155 mg/kg) twice a week for the same four weeks; group 2 received only mitomycin C and 5-fluorouracil; group 3 received only calcium gluconate; group 4 received a vehicle (physiological saline). Significantly enhanced inhibition of tumor growth was observed neither in a comparison between groups 3 and 4, nor in a comparison between groups 1 and 2 (expect on day 20 post implantation). Thus calcium gluconate given alone or in combination with antitumor agents hardly appeared to possess effective antitumor activity.

Animals↗
PubMed1993

Effect of various dietary constituents on gastrointestinal absorption of aluminum from drinking water and diet.

The influence of some frequent dietary constituents on gastrointestinal absorption of aluminum from drinking water and diet was investigated in mice. Eight groups of male mice received lactic (57.6 mg/kg/day), tartaric (96 mg/kg/day), gluconic (125.4 mg/kg/day), malic (85.8 mg/kg/day), succinic (75.6 mg/kg/day), ascorbic (112.6 mg/kg/day), citric (124 mg/kg/day), and oxalic (80.6 mg/kg/day) acids in the drinking water for one month. At the end of this period, animals were killed and aluminum concentrations in liver, spleen, kidney, brain, and bone were determined. All the dietary constituents significantly increased the aluminum levels in bone, whereas brain aluminum concentrations were also raised by the intake of lactic, gluconic, malic, citric, and oxalic acids. The levels of aluminum found in spleen were significantly increased by gluconic and ascorbic acids, whereas gluconic and oxalic acids also raised the concentrations of aluminum found in kidneys. Because of the wide presence and consumption of the above dietary constituents, in order to prevent aluminum accumulation and toxicity we suggest a drastic limitation of human exposure to aluminum.

Aluminum↗
PubMed2003

Efficacy of selected hand hygiene agents used to remove Bacillus atrophaeus (a surrogate of Bacillus anthracis) from contaminated hands.

CONTEXT: The intentional use of Bacillus anthracis transmitted via the US mail in October-November 2001 resulted in 22 people developing inhalation or cutaneous anthrax. Glove use with handwashing prior to and after contact with potential contaminated environmental surfaces and cutaneous lesions has been recommended. However, only limited data are available on the susceptibility of B anthracis to antiseptics. OBJECTIVE: To evaluate the efficacy of several hand antiseptics (interventions) and soap and water (control) against Bacillus atrophaeus, a surrogate of B anthracis. DESIGN, SETTING, AND PARTICIPANTS: Challenge study conducted among healthy adult volunteers, using the Standard Test Method for Evaluation of the Effectiveness of Health Care Professional Handwash Formulations (American Society for Testing and Materials E 1174-94) to determine the efficacy of various hand hygiene products at wash times of 10, 30, and 60 seconds. Volunteers were excluded if they had eczema, psoriasis, or other chronic skin conditions; nonintact skin; or allergies to any study agent. Study agents were a waterless rub containing 61% ethyl alcohol, a 2% chlorhexidine gluconate preparation, and an antibacterial microfiber towel that releases hypochlorite. A nonantimicrobial soap was used as a control. MAIN OUTCOME MEASURE: Reduction of B atrophaeus spores (log10 CFU/mL) on contaminated hands. RESULTS: Washes of 10, 30, and 60 seconds with either soap and water or 2% chlorhexidine gluconate eliminated 1.5 to 2.0 log10 CFUs/mL of B atrophaeus spores at wash 3. Mean reductions (95% confidence intervals) with 10-, 30-, and 60-second washes with soap and water were 2.4 (2.2-2.5), 2.3 (2.2-2.4), and 2.1 (1.9-2.4) log(10) CFUs/mL, respectively; and with 2% chlorhexidine gluconate, 2.1 (2.0-2.3), 1.8 (1.5-2.0), and 1.7 (1.5-1.9) log10 CFUs/mL, respectively. Handwashing with chlorine-containing towels was increasingly effective as the wipe time increased; reductions at 10, 30, and 60 seconds were 1.3 (1.1-1.5), 1.6 (1.2-2.0), and 2.2 (2.1-2.2) log10 CFUs/mL, respectively. A waterless rub containing 61% ethyl alcohol was ineffective in eliminating B atrophaeus spores at all times tested (0 [-0.1 to 0.1], -0.2 [-0.3 to -0.1], and 0 [-0.2 to 0.2] log10 CFUs/mL). CONCLUSIONS: In this evaluation of hand hygiene agents, handwashing with soap and water, 2% chlorhexidine gluconate, or chlorine-containing towels reduced the amount of B atrophaeus spore contamination, whereas use of a waterless rub containing ethyl alcohol was not effective in removing spores.

Adult↗
PubMed1997

Cutaneous transport of Ca2+ in the frog Rana pipiens: significance and specificity.

Rana pipiens were divided into four groups: controls; hypocalcemic frogs, depleted of salts by acclimation to deionized water; hypercalcemic frogs, calcium-loaded by the introduction of 40 mumol calcium gluconate; and frogs exposed to the potential competing ions Mg2+, Sr2+, and Ba2+. All groups displayed calcium influx that was proportional to external [Ca2+]; however, the group acclimated to deionized water also displayed hypocalcemia (P < 0.025) and enhanced Ca2+ influx at higher (> 0.3 mM) external [Ca2+]. Ca2+ efflux was depressed in hypocalcemic frogs, and thus net Ca2+ flux shifted from net loss in control frogs to net uptake in hypocalcemic frogs. Hypocalcemia also resulted in increased skin Ca2+ deposits which may be related to a decreased Ca2+ (and other ions) permeability as a consequence of the acclimation to deionized water. Another group of frogs was Ca(2+)-loaded by injecting calcium gluconate: Sodium gluconate controls did not significantly alter Ca2+ fluxes. The frogs that received calcium gluconate treatments became hypercalcemic (P < 0.01) and did not display significant changes in calcium fluxes, nor did they show significant changes in skin calcium deposits. We conclude that hypocalcemia leads to regulatory responses that stimulate active Ca2+ transport in Rana pipiens skin and possibly inhibits cutaneous and renal efflux. We also conclude that hypercalcemia does not alter calcium fluxes across skin. The ions from Group IIA of the Periodic Table of Elements had little effect on Ca2+ fluxes at concentrations ranging from 0.5-4.0 mM; neither Sr2+ or Ba2+ affected Ca2+ influx. The only divalent ion tested that influenced Ca2+ was Mg2+, which significantly inhibited Ca2+ influx but only at 4.0 mM or eight times the external [Ca2+]. We conclude, therefore, that the Ca2+ transport mechanism is fairly specific for Ca2+ within Group IIA.

Animals↗
PubMed2005

Intravenous iron in a primary-care clinic.

The preferable route of iron delivery for most iron-deficient patients is oral. Parenteral iron therapy is used in patients who cannot tolerate oral iron or in cases in which oral iron is not sufficiently effective. The most frequent indications for parenteral iron therapy are unbearable gastrointestinal side effects induced by oral iron itself, worsening of inflammatory bowel disease symptoms, insufficient intestinal absorption, renal failure-caused anemia that is treated with erythropoietin, and unresolved ongoing bleeding, which would cause the acceptable oral doses of iron therapy to be exceeded. The serious adverse effects of iron dextran that was used in the past could explain the reluctance of medical personnel to prescribe this effective treatment. Patients with iron deficiency anemia were treated with intravenous iron in a primary care clinic. The iron gluconate was given in a dosage of 62.5 mg diluted in 150 mL of normal saline and was infused intravenously over 30 min, while iron sucrose was given in a dosage of 100 mg diluted in the same volume of normal saline and given at the same rate. In total, 724 infusions were administered to 57 patients. Iron sucrose was used in 628 infusions, and iron gluconate was used in the remaining 96. The frequency of the infusion treatments depended on the underlying disease and ranged from three times a week to once a month. Adverse effects were seldom observed and were minor in patients receiving iron gluconate, and were not registered at all in patients treated with iron sucrose. Two cases of flushing with paresthesias occurred. Slowing the infusion rate successfully eliminated these side effects. One case of hypotension was treated successfully with 500 cc of normal saline infusion. One case of dropout occurred, due to the patient's refusal to cooperate. No anaphylactic reactions were observed. Iron gluconate and iron sucrose are effective and safe for use in primary care clinics. The risk of adverse effects is low.

Anemia, Iron-Deficiency↗
PubMedDate not supplied

Comparative quinidine plasma profiles at steady state of two controlled-release products and quinidine sulfate in solution.

A study was conducted to compare, at steady state, the plasma quinidine level profiles of two commercial controlled-release products (quinidine sulfate controlled release and quinidine gluconate controlled release) with quinidine sulfate given in solution. Twenty-four healthy volunteers entered the study and 23 completed it. Quinidine formulations were given at 600 mg day-1 for 4 days in each of three periods in a randomized crossover study. In addition to frequent blood sampling on the fourth day of each period, samples were taken during the approach to steady state to confirm by minimum plasma concentrations (Cmin) that steady state had been attained. Quinidine concentrations were measured by using a high-performance liquid chromatographic assay specific for quinidine. The bioavailability of the two controlled-release products relative to quinidine sulfate in solution was adequate when dose correction to account for differences in quinidine base content was done. Without dose correction, the area under the plasma concentration-time curve (AUC) for the quinidine gluconate form was 85 per cent that of the solution: an amount equivalent to the relative actual amount of quinidine base in the quinidine gluconate dosage form. The maximum plasma concentration (Cmax), Cmin, peak-to-trough differences, and AUC from the quinidine sulfate extended-release form given 300 mg q12h were similar to the solution given 150 mg q6h. With dose correction, the quinidine gluconate controlled-release form given q12h had equivalent AUC but larger peak-to-trough differences than either the quinidine sulfate extended-release product given q12h or quinidine sulfate in solution given q6h.

Adult↗
PubMed1997

The efficacy of antioxidants administered during low temperature storage of warm ischemic kidney tissue slices.

Accumulation of products of lipid peroxidation (malondialdehyde, conjugated dienes, lipid peroxides, and Schiff bases) was evaluated in rabbit kidney cortex slices made ischemic for 60 min followed by 18 h storage at 5 degrees C in UW Na gluconate solution and 210 min normothermic reoxygenated incubation. In addition, the effect of adding Trolox (1 mM), deferoxamine (1 mM), and ascorbate (1 mM) as supplemental antioxidants to the UW gluconate solution was evaluated. Lipid peroxidation was slightly increased after hypothermic storage compared to slices subjected to ischemia alone but was not significantly different than ischemic slices during subsequent incubation at normothermia. The addition of either deferoxamine or Trolox to the storage solution substantially reduced lipid peroxidation both during hypothermic storage and subsequent to normothermic incubation. Ascorbate had a mild prooxidant effect as a sole additive to the UW gluconate solution but was clearly prooxidant when combined with either deferoxamine or Trolox. These results suggest that supplemental antioxidants added to the UW gluconate solution under conditions analogous to machine perfusion preservation have a potential role in reducing oxidative stress in kidney tissues harvested after warm ischemia and that hypothermia may be a valuable adjunct to resuscitative therapeutic regimens developed for salvage of ischemic kidneys for transplantation.

Animals↗
PubMed1993

Co-expression of an anion conductance pathway with Na(+)-glucose cotransport in rat renal brush-border membrane vesicles.

Brush-border membrane vesicles were prepared from superficial rat renal cortex by a Mg(2+)-precipitation technique. The initial (20 s) [14C]glucose uptake rate from solutions containing 100 mmol/l Na (salt) was found to be dependent upon the anion composition of the medium; in comparison to gluconate-containing medium (0.46 +/- 0.05 nmol/mg protein), Cl- accelerated the initial rate to 1.47 +/- 0.21 nmol/mg protein (n = 4 preparations, +/- SEM). This enhancement was reduced by 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB, 0.5 mmol/l), but was unaffected by 4,4'-diisothiocyanatostilbene 2,2'-disulphonate (DIDS, 0.5 mmol/l). When membrane vesicles were pre-equilibrated with 100 mmol/l K (salt) and 100 mmol/l mannitol and glucose uptake was measured from a solution containing 100 mmol/l Na gluconate and 100 mmol/l mannitol in the presence of 80 mumol/l valinomycin (to generate an outward K+ diffusion electrical p. d.), it was found that intravesicular KCl depressed the initial glucose uptake compared to K gluconate. NPPB (0.5 mmol/l) increased the initial glucose uptake with intravesicular KCl towards values seen in K gluconate vesicles. In conditions where the only driving force for glucose uptake was established by an inward anion gradient (Nao = Nai) it was found that inward Cl- gradients could drive uphill glucose transport and that this was sensitive to NPPB (0.5 mmol/l), but insensitive to DIDS. We conclude that a Cl- conductance co-exists with Na-cotransport in rat renal brush-border membrane vesicles prepared from superficial renal cortex and this may function to regulate the activity of electrogenic transport systems at this membrane.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1987

Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney. I. Kinetics, influence of cations, anions, and capillary preperfusion.

In order to study the characteristics of contraluminal para-aminohippurate transport into proximal tubular cells the stopped flow capillary perfusion method was applied. The disappearance of 3H-para-aminohippurate from the capillary perfusate at different concentrations and contact times was measured and saturation type behaviour was found with a Km of 0.08 +/- 0.01 (SE) mmol/l, Jmax of 1.1 +/- 0.1 pmol X s-1 X cm-1 and r, the final extracellular/intracellular distribution ratio of 0.93 +/- 0.03. Omission of Na+ from the capillary test perfusate caused a small reduction of contraluminal PAH uptake at small transport rates (0.1 mmol/l PAH in the test perfusate) but not at high transport rates (1.0 mmol/l PAH in the test perfusate). Change of K+ between 0 and 40 mmol/l and pH between 6.0 and 8.0 did not influence contraluminal PAH uptake. Isotonic replacement of chloride by gluconate, nitrate, sulfate, phosphate, methanesulfonate or increase in bicarbonate to 50 mmol/l did not influence PAH uptake at small transport rates. But isotonic sulfate and phosphate, as well as 50 mmol/l HCO3- and 25 mmol/l Hepes in isotonic solutions reduced PAH uptake at high transport rates. Addition of 5 mmol/l Ca2+, Mg2+, Mn2+, Ba2+, Cd2+ to isotonic Na+-gluconate solution did not influence PAH uptake except for Mg2+ and Mn2+ which inhibited uptake at small transport rates only. Preperfusion of the peritubular capillaries with rat serum, Na+ gluconate (Ca2+- + Mg2+-free), Na+ gluconate (Ca2+- + Mg2+-free) plus 10 mmol/l lactate or pyruvate or 0.1 mmol/l 2-oxoglutarate did not influence PAH uptake at small PAH transport rates, but inhibited at high transport rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminohippuric Acids↗
PubMed1989

Ca2+ pumping ATPase of cardiac sarcolemma is insensitive to membrane potential produced by K+ and Cl- gradients but requires a source of counter-transportable H+.

The sensitivity of the Ca2+ pumping ATPase of bovine cardiac sarcolemma (SL) to changes in membrane potential was studied in a preparation of sealed SL vesicles. Membrane potential was imposed by preincubating the vesicles in media of defined ion composition (K+, Cl-, choline+ and gluconate-) and diluting into media of differing ion composition. The durations of the ion gradients and relative ion permeabilities were determined in separate experiments by the dependence of the half time for net K+ (or choline+) movement coupled with these anions (Cl- or gluconate-), registered by the fluorescence of 1-anilino-8-naphthalene sulfonate (Chiu, V.C.K., Haynes, D.H. 1980. J. Membrane Biol. 56:203-218). Relative permeabilities were: 1.0, K+; greater than or equal to 10.0, 1 microM valinomycin-K+; 4.0, Cl-; 0.66, choline+; 0.38, gluconate-. Durations of the gradients ranged between 17 sec (KCl, valinomycin) to 195 sec (K(+)-gluconate-). In separate experiments, active Ca2+ uptake was monitored using chlorotetracycline (CTC) fluorescence, a technique validated by 45-Ca2+ measurements (Dixon, D., Brandt, N., Haynes, D.H. 1984. J. Biol. Chem. 259:13737-13741). Active Ca2+ uptake was initiated in the presence of monovalent ion gradients. The values of the membrane potentials (Em) imposed by the monovalent ion gradients were calculated using the ion concentrations, their relative permeabilities and the Goldman-Hodgkin-Katz equation. No effect of membrane potential on transport rate was observed (less than or equal to 4%, for 5-7% SD) for imposed potentials as extreme as greater than or equal to +71 and less than or equal to -67 mV. Formal analysis shows that the above observations are not compatible with models in which the Ca2+ pumping ATPase functions in an electrogenic or charge-uncompensated fashion. Further experimentation showed that the pump rate is slowed when uptake is measured at less-than-adequate concentrations of buffer (5 vs. 25 mM HEPES/Tris). This, together with further control experiments using nigericin and FCCP, gave evidence that the pump requires a source of counter-transportable H+ in the vesicle lumen. The above experimentation also underlines the need for control of internal pH to obviate erroneous interpretation of ion perturbation experiments. The results are compared with results obtained with the Ca2+ ATPase pump of skeletal sarcoplasmic reticulum.

Animals↗
PubMed2000

The carbon source influences the energetic efficiency of the respiratory chain of N2-fixing Acetobacter diazotrophicus.

Acetobacter diazotrophicus is a diazotrophic bacterium that colonizes sugarcane tissues. Glucose is oxidized to gluconate in the periplasm prior to uptake and metabolism. A membrane-bound glucose dehydrogenase quinoenzyme [which contains pyrroloquinoline quinone (PQQ) as the prosthetic group] is involved in that oxidation. Gluconate is oxidized further via the hexose monophosphate pathway and tricarboxylic acid cycle. A. diazotrophicus PAL3 was grown in a chemostat with atmospheric nitrogen as the sole N source provided that the dissolved oxygen was maintained at 1.0-2.0% air saturation. The biomass yields of A. diazotrophicus growing with glucose or gluconate with fixed N were very low compared with other heterotrophic bacteria. The biomass yields under N-fixing conditions were more than 30% less than with ammonium as the N source using gluconate as the carbon source but, surprisingly, were only about 14% less with glucose. The following scheme for the metabolism of A. diazotrophicus through the different pathways emerged: (1) the respiratory chain of this organism had a different efficiency of ATP production in the respiratory chain (P:O ratio) under different culture conditions; and (2) N fixation was one (but not the sole) condition under which a higher P:O ratio was observed. The other condition appears to be the expression of an active PQQ-linked glucose dehydrogenase.

Acetobacter↗
PubMed1988

Intraventricular administration of the cholinotoxin AF64A increases the accumulation of aluminum in the rat parietal cortex and hippocampus, but not in the frontal cortex.

Aluminum (Al) concentrations of the rat frontal cortex, parietal cortex, and hippocampus were measured by atomic absorption spectroscopy 16 days after a unilateral intracerebroventricular injection of Na gluconate, Al gluconate, or the cholinotoxin AF64A. A fourth group of rats were injected with AF64A 6 days before injection of Al gluconate and subsequently sacrificed 10 days later. The combined treatment of AF64A and Al gluconate resulted in enhanced intraneuronal accumulation of Al in the parietal cortex and hippocampus but not in the frontal cortex. Consequently, Al may not be considered to be a primary factor in the pathogenesis of Alzheimer's disease.

Aluminum↗
PubMed1988

The effect of chlorhexidine irrigation on the incidence of dry socket: a pilot study.

A pilot study was conducted to measure the reported incidence of dry socket following pre-operative irrigation and mouthrinsing with either 0.2% (w/v) chlorhexidine gluconate or normal saline or with no irrigation (control). Three hundred and twenty-four patients presenting for the single extraction of a lower premolar or molar under local anaesthesia were divided into three equal groups; no irrigation, irrigation with saline and irrigation with a 0.2% (w/v) chlorhexidine gluconate solution. After administration of the local anaesthetic agent, 10 ml of the test solutions were applied to the gingival crevice using a blunted needle. The solutions were retained in the patients mouth for 2 min following irrigation. Pre-operative irrigation of the gingival crevice and mouthrinsing with 0.2% (w/v) chlorhexidine gluconate significantly reduced the number of dry sockets. There was no significant reduction in the number of dry socket cases following irrigation and rinsing with normal saline. The irrigation technique, using 0.2% (w/v) chlorhexidine gluconate is safe, inexpensive, easy to apply and can be recommended for routine use in dental practice, to reduce the incidence of dry socket.

Bicuspid↗
PubMed2004

Structure of carbohydrate-bound polynuclear iron oxyhydroxide nanoparticles in parenteral formulations.

Intravenous iron therapy is used to treat anemia associated with chronic kidney disease. The chemical structures of parenteral iron agents have not been characterized in detail, and correlations between structure, efficiency of iron delivery, and toxicity via catalysis of oxygen-derived free radical creation remain to be established. In this study, two formulations of parenteral iron have been characterized by absorption spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), and elemental analysis. The samples studied were Venofer (Iron Sucrose Injection, USP) and Ferrlecit (Sodium Ferric Gluconate in Sucrose Injection). The 250-800-nm absorption spectra and the XRD patterns showed that both formulations contain a mineral core composed of iron oxyhydroxide in the beta-FeOOH mineral polymorph known as akaganeite. This was further confirmed for each formulation by imaging using TEM and AFM. The average core size for the nanoparticles, after dialysis to remove unbound or loosely bound carbohydrate, was approximately 3+/-2 nm for the iron-sucrose, and approximately 2+/-1 nm for the iron-gluconate. Each of the nanoparticles consists of a mineral core, surrounded by a layer of bound carbohydrate. The overall diameter of the average bead in the dialyzed preparations was approximately 7+/-4 nm for the iron-sucrose, and 3+/-1 nm for the iron-gluconate. Undialyzed preparations have particles with larger average sizes, depending on the extent of dilution of unbound and loosely bound carbohydrate. At a dilution corresponding to a final Fe concentration of 5 mg/mL, the average particle diameter in the iron-sucrose formulation was approximately 22+/-9 nm, whereas that of the iron-gluconate formulation was approximately 12+/-5 nm.

Journal Article↗
PubMed1994

Mechanism of chloride-dependent release of Ca2+ in the sarcoplasmic reticulum of rabbit skeletal muscle.

We investigated the effect of Cl- on the Ca2+ permeability of rabbit skeletal muscle junctional sarcoplasmic reticulum (SR) using 45Ca2+ fluxes and single channel recordings. In 45Ca2+ efflux experiments, the lumen of the SR was passively loaded with solutions of 150 mM univalent salt containing 5 mM 45Ca2+. Release of 45Ca2+ was measured by rapid filtration in the presence of extravesicular 0.4-0.8 microM free Ca2+ and 150 mM of the same univalent salt loaded into the SR lumen. The rate of release was 5-10 times higher when the univalent salt equilibrated across the SR-contained Cl- (Tris-Cl, choline-Cl, KCl) instead of an organic anion or other halides (gluconate-, methanesulfonate-, acetate-, HEPES-, Br-, I-). Cations (K+, Tris+) could be interchanged without a significant effect on the release rate. To determine whether Cl- stimulated ryanodine receptors, we measured the stimulation of release by ATP (5 mM total) and caffeine (20 mM total) and the inhibition by Mg2+ (0.8 mM estimated free) in Cl(-)-free and Cl(-)-containing solutions. The effects of ATP, caffeine, and Mg2+ were the largest in K-gluconate and Tris-gluconate, intermediate in KCl, and notably poor or absent in choline-Cl and Tris-Cl. Procaine (10 mM) inhibited the caffeine-stimulated release measured in K-gluconate, whereas the Cl- channel blocker clofibric acid (10 mM) but not procaine inhibited the caffeine-insensitive release measured in choline-Cl. Ruthenium red (20 microM) inhibited release in all solutions. In SR fused to planar bilayers we identified a nonselective Cl- channel (PCl: PTris: PCa = 1:0.5:0.3) blocked by ruthenium red and clofibric acid but not by procaine. These conductive and pharmacological properties suggested the channel was likely to mediate Cl(-)-dependent SR Ca2+ release. The absence of a contribution of ryanodine receptors to the Cl(-)-dependent release were indicated by the lack of an effect of Cl- on the open probability of this channel, a complete block by procaine, and a stimulation rather than inhibition by clofibric acid. A plug model of Cl(-)-dependent release, whereby Cl- removed the inhibition of the nonselective channel by large anions, was formulated under the assumption that nonselective channels and ryanodine receptor channels operated separately from each other in the terminal cisternae. The remarkably large contribution of Cl- to the SR Ca2+ permeability suggested that nonselective Cl- channels may control the Ca2+ permeability of the SR in the resting muscle cell.

Adenosine Triphosphate↗
PubMed1996

Microbial contamination of antiseptics and disinfectants.

BACKGROUND: There have been a number of reports on microbial contamination of antiseptics and disinfectants. At present, however, the necessity of measures to prevent contamination do not seem to be fully appreciated. We investigated microbial contamination of antiseptics and disinfectants that are used in our hospital. METHODS: Fifty-one samples of benzalkonium chloride and chlorhexidine gluconate that were being used in the hospital were examined. Viability of the contaminants detected in these samples was also tested in the agents. Then we examined measures to prevent contamination of these agents. RESULTS: Microbial contamination was detected at 10(2) to 10(7) CFU/ml in the following samples: 6 of 23 samples of cotton balls soaked in 0.02% benzalkonium chloride kept in a canister for antisepsis and disinfection (26.1%); 7 of 13 samples of 0.02%, benzalkonium chloride or 0.02% chlorhexidine gluconate in an irrigation apparatus kept at 37 degrees C for vaginal douching (53.8%); and 9 of 15 samples of 0.02% benzalkonium chloride or 0.05% chlorhexidine gluconate for storage of suction catheters in a plastic bottle (60%). The major contaminants were Burkholderia cepacia, Pseudomonas aeruginosa, Xanthomonas maltophilia, and Pseudomonas fluorescens. The first two organisms examined grew in the agents. After improvements in the handling of the antiseptics and disinfectants, no microbial contamination was observed. CONCLUSIONS: It is necessary to check microbial contamination of diluted benzalkonium chloride and diluted chlorhexidine gluconate that are in use. Such products are not recommended as antiseptics.

Anti-Infective Agents, Local↗
PubMed2003

Membrane-derived oligosaccharides (MDOs) are essential for sodium dodecyl sulfate resistance in Escherichia coli.

We studied the role of membrane-derived oligosaccharides (MDOs) in sodium dodecyl sulfate (SDS) resistance by Escherichia coli. MDOs are also known as osmoregulated periplasmic glucans. Wild-type E. coli MC4100 grew in the presence of 10% SDS whereas isogenic mdoA and mdoB mutants could not grow above 0.5% SDS. Similarly, E. coli DF214, a mutant (pgi, zwf) unable to grow on glucose, exhibited conditional sensitivity to SDS in that it grew in gluconate and glucose or galactose but not in gluconate and mannose or sorbose. DF214 requires both gluconate and glucose/galactose because the gluconate is used for energy production, while glucose/galactose is used for MDO synthesis. Finally, the fate of E. coli cells subjected to SDS shock either during growth or when used as an inoculum is dependent on the presence or absence of sufficient MDOs. In both cases, cells grown under high-osmolarity (low-MDO) conditions were rapidly lysed by 5% SDS. Based on findings from a wild-type E. coli (MC4100), two mdo mutants and strain DF214 we conclude that MDOs are required for SDS resistance.

Cations↗