An electrochemical sensor for (L)-dopa based on oxovanadium-salen thin film electrode applied flow injection system

An oxovanadium-salen complex (NAP-ethylene-bis(salicylidenciminato) oxovanadium) thin film deposited on a graphite-polyurethane electrode was investigated with regard to its potential use for detection of L-dopa in flow injection system. The oxovanadium(IV)/oxovanadium(V) redox couple of the modified electrode was found to mediate the L-dopa oxidation before its use in the FIA system. Experimental parameters, such as pH of the carrier solution, flow rate, sample volume injection and probable interferents were investigated. Under the optimized FIA conditions, the amperometric signal was linearly dependent on the L-dopa concentration over the range 1.0 x 10(-1) to 1.0 x 10(-4) mol L-1 (I-anodic, mu A) = 0.01 + 0.25 [L-dopa mu mol L-1]) with a detection limit (S/N = 3) of 8.0 x 10(-7) mol L-1 and a sampling frequency of 90 h(-1) was achieved. For a concentration of 1.0 x 10(-5) mol L-1 L-dopa, the R.S.D. of nine consecutive measurements was 3.7%. (c) 2006 Elsevier B.V. All rights reserved.

A Single Intraoperative Sub-Tenon's Capsule Injection of Triamcinolone and Ciprofloxacin in a Controlled-Release System for Cataract Surgery

PURPOSE. To compare intraoperative injection of triamcinolone and ciprofloxacin in a controlled-release system (DuoCat) with prednisolone and ciprofloxacin eye drops after cataract surgery.METHODS. In this randomized, double-masked, controlled trial, a total of 135 patients undergoing cataract surgery were randomly allocated to two groups: 67 patients treated after surgery with prednisolone 1% and ciprofloxacin 3% eye drops four times daily (week 1), three times daily (week 2), twice daily (week 3), and once daily (week 4) and 0.3% ciprofloxacin drops four times daily (weeks 1 and 2), and 68 patients treated at the end of surgery with a sub-Tenon's injection of 25 mg triamcinolone and 2 mg ciprofloxacin in biodegradable microspheres. The patients were examined on postoperative days 1, 3, 7, 14, and 28. The main outcome measures were postoperative anterior chamber cell and flare, intraocular pressure (IOP), lack of anti-inflammatory response, and presence of infection.RESULTS. No significant differences were observed between the groups in anterior chamber cell (P > 0.14) and flare (P > 0.02) at any postoperative visits. The mean (99% confidence interval) differences in IOP between the prednisolone and triamcinolone groups on days 1, 3, 7, 14, and 28 were -0.4 mm Hg (-2.1 to 1.3), 0.0 mm Hg (-1.4 to 1.3), 0.0 mm Hg (-1.1 to 1.1), -0.2 mm Hg (-1.1 to 0.8), and -0.1 mm Hg (-1.1 to 0.9), respectively. No patient had a postoperative infection.CONCLUSIONS. One injection of DuoCat had a therapeutic response and ocular tolerance that were equivalent to conventional eye drops in controlling inflammation after cataract surgery. (Clinical-Trials. gov number, NCT00431028.) (Invest Ophthalmol Vis Sci. 2009; 50: 3041-3047) DOI: 10.1167/iovs.08-2920

Role of nitric oxide and beta-adrenoceptors of the central nervous system on the salivary flow induced by pilocarpine injection into the lateral ventricle

Our studies have focused on the effect of L-NG-nitroarginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), and L-arginine, the substrate of NOS, on salivary secretion induced by the administration of pilocarpine into the lateral cerebral ventricle (LV) of rats. The present study has also investigated the role of the beta-adrenergic agonists and antagonist injected into LV on the salivary secretion elicited by the injection of pilocarpine into LV. Male Holtzmann rats with a stainless-steel cannula implanted into the LV were used. The amount of salivary secretion was studied over a 7-min period after injection of pilocarpine, isoproterenol, propranolol, salbutamol, salmeterol, L-NAME and L-arginine. The injection of pilocarpine (10, 20, 40, 80 and 160 mug/mul) into LV produced a dose-dependent increase in salivary secretion. The injection of L-NAME (40 mug/mul) into LV alone produced an increase in salivary secretion. The injection of L-NAME into LV previous to the injection of pilocarpine produced an increase in salivary secretion. L-Arginine (30 mug/mul) injected alone into LV produced no change in salivary secretion. L-Arginine injected into LV attenuated pilocarpine-induced salivary secretion. The isoproterenol (40 nmol/mul) injected into LV increased into LV increased the salivary secretion. When injected previous to pilocarpine at a dose of 20 and 40 mug/mul, isoproterenol produced and additive effect on pilocarpine-induced salivary secretion. The 40-nmol/mul dose of propranolol injected alone or previous to pilocarpine into LV attenuated the pilocarpine-induced salivary secretion. The injection of salbutamol (40 nmol/mul), a specific beta-2 agonist, injected alone into LV produced no change in salivary secretion and when injected previous to pilocarpine produced and increase in salivary secretion. The 40-nmol/mul dose of salmeterol, a long-acting beta-2 agonist, injected into LV alone or previous to pilocarpine produced no change in salivary secretion. The results have shown that central injections of L-NAME and L-arginine interfere with the salivary secretion, which implies that might participate in pilocarpine-induced salivary secretion. The interaction between cholinergic and beta-adrenergic receptors of the central nervous system (CNS) for the control of salivary secretion can also be postulated. (C) 2002 Elsevier B.V. All rights reserved.

High current-density anodic electro-dissolution in flow-injection systems for the determination of aluminium, copper and zinc in non-ferroalloys by flame atomic absorption spectrometry

An automatic Procedure with a high current-density anodic electrodissolution unit (HDAE) is proposed for the determination of aluminium, copper and zinc in non-ferroalloys by flame atonic absorption spectrometry, based on the direct solid analysis. It consists of solenoid valve-based commutation in a flow-injection system for on-line sample electro-dissolution and calibration with one multi-element standard, an electrolytic cell equipped with two electrodes (a silver needle acts as cathode, and sample as anode), and an intelligent unit. The latter is assembled in a PC-compatible microcomputer for instrument control, and far data acquisition and processing. General management of the process is achieved by use of software written in Pascal. Electrolyte compositions, flow rates, commutation times, applied current and electrolysis time mere investigated. A 0.5 mol l(-1) HNO3 solution was elected as electrolyte and 300 A/cm(2) as the continuous current pulse. The performance of the proposed system was evaluated by analysing aluminium in Al-allay samples, and copper/zinc in brass and bronze samples, respectively. The system handles about 50 samples per hour. Results are precise (R.S.D < 2%) and in agreement with those obtained by ICP-AES and spectrophotometry at a 95% confidence level.

Spectrophotometric determination of phosphite in fertilizers in a flow injection system with online sample preparation

A flow injection system with online sample preparation is proposed for the determination of phosphite in liquid fertilizers by spectrophotometry. After loop-based injection, phosphite is oxidized by an acidic permanganate solution (1.0 10(-2) mol L-1 KMnO4 + 1.0 mol L-1 H2SO4) in a heated reactor (50 degreesC). The phosphate generated is then determined by the molybdenum blue method. Influence of flow rates, temperature, and concentration and order of addition of reagents, sample volume, and reactor configuration for the blue complex formation on recorded signals were investigated. The pow system was applied to phosphite determination in commercial samples of liquid fertilizers. The proposed system handles about 80 samples per hour [0.05-0.40% (w/v) H3PO3; R = 0,9998], consuming about 80 muL sample, 1 mg KMnO4, 25 mg (NH)(6)Mo7O24, and Ia mg ascorbic acid per determination. Results are precise [relative standard deviation less than or equal to 3.5% for 0.1% (w/v) H3PO3, n = 12] and in agreement with those obtained by gravimetry at 95% confidence level. (C) 2000 John Wiley & Sons, Inc.

Flow injection amperometric detection of ascorbic acid using a Prussian Blue film-modified electrode

The PB film-modified electrode was used as an amperometric detector for flow injection analysis of ascorbic acid. The modified electrode detector showed good sensitivity, stability and reproducibility. The calibration curve for ascorbic acid was linear over the concentration range from 5.0 x 10(-6) to 1.0 x 10(-3) mol l(-1) with a slope of 19.9 mA mol(-1) per litre and a correlation coefficient of 0.999. The detection limit of this method was 2.49 x 10(-6) mol l(-1). The relative standard deviation of six replicate injections of 2.5 x 10(-4) mol l(-1) ascorbic acid was 2.5%. The results obtained for ascorbic acid determination in pharmaceutical products are in good agreement with those obtained by using the procedure involving the reaction between triiodide and ascorbic acid. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Spectrophotometric detection of arsenic using flow-injection hydride generation following sorbent extraction preconcentration

An automated system with a C-18 bonded silica gel packed minicolumn is proposed for spectrophotometric detection of arsenic using flow-injection hydride generation following sorbent extraction preconcentration. Complexes formed between arsenic(III) and ammonium diethyl dithiophosphate (ADDP) are retained on a C-18 sorbent. The eluted As-DDP complexes are merged with a 1.5% (w/v) NaBH4 and the resulting solution is thereafter injected into the hydride generator/gas-liquid separator. The arsine generated is carried out by a stream of N-2 and trapped in an alkaline iodine solution in which the analyte is determined by the arsenomolybdenum blue method. With preconcentration time of 120 s, calibration in the 5.00-50.0 mu g As l(-1) range and sampling rate of about 20 samples h(-1) are achieved, corresponding to 36 mg ADDP plus 36 mg ammonium heptamolybdate plus 7 mg hydrazine sulfate plus 0.7 mg stannous chloride and about 7 mi sample consumed per determination. The detection limit is 0.06 mu g l(-1) and the relative standard deviation (n = 12) for a typical 17.0 mu g As l(-1) sample is ca. 6%. The accuracy was checked for arsenic determination in plant materials from the NIST (1572 citrus leaves; 1573 tomato leaves) and the results were in agreement with the certified values at 95% confidence level. Good recoveries (94-104%) of spiked tap waters, sugars and synthetic mixtures of trivalent and pentavalent arsenic were also found. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Functional evidence that the central renin-angiotensin system plays a role in the pressor response induced by central injection of carbachol

We investigated the effects of losartan, an AT 1-receptor blocker, and ramipril, a converting enzyme inhibitor, on the pressor response induced by angiotensin II (ANG II) and carbachol (a cholinergic receptor agonist). Male Holtzman rats (250-300 g) with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The injection of losartan (50 nmol/l μl) into the LV blocked the pressor response induced by ANG II (12 ng/l μl) and carbachol (2 nmol/l μl). After injection of ANG II and carbachol into the LV, mean arterial pressure (MAP) increased to 31 ± 1 and 28 ± 2 mmHg, respectively. Previous injection of losartan abolished the increase in MAP induced by ANG II and carbachol into the LV (2 ± 1 and 5 ± 2 mmHg, respectively). The injection of ramipril (12 ng/l μl) prior to carbachol blocked the pressor effect of carbachol to 7 ± 3 mmHg. These results suggest an interaction between central cholinergic pathways and the angiotensinergic system in the regulation of arterial blood pressure.

A simple and rapid screening method for sulfonamides in honey using a flow injection system coupled to a liquid waveguide capillary cell

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Screening and determination of sulphonamide residues in bovine milk samples using a flow injection system

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The adrenergic regulation of the cardiovascular system in the South American rattlesnake, Crotalus durissus

The present study investigates adrenergic regulation of the systemic and pulmonary circulations of the anaesthetised South American rattlesnake, Crotalus durissus. Haemodynamic measurements were made following bolus injections of adrenaline and adrenergic antagonists administered through a systemic arterial catheter. Adrenaline caused a marked systemic vasoconstriction that was abolished by phentolamine, indicating this response was mediated through alpha-adrenergic receptors. Injection of phentolamine gave rise to a pronounced vasodilatation (systemic conductance (G(sys)) more than doubled), while injection of propranolol caused a systemic vasoconstriction, pointing to a potent alpha-adrenergic, and a weaker beta-adrenergic tone in the systemic vasculature of Crotalus. Overall, the pulmonary vasculature was far less responsive to adrenergic stimulation than the systemic circulation. Adrenaline caused a small but non-significant pulmonary vasodilatation and there was tendency of reducing this dilatation after either phentolamine or propranolol. Injection of phentolamine increased pulmonary conductance (G(pul)), while injection of propranolol produced a small pulmonary constriction, indicating that alpha-adrenergic and beta-adrenergic receptors contribute to a basal regulation of the pulmonary vasculature. Our results suggest adrenergic regulation of the systemic vasculature, rather than the pultrionary, may be an important factor in the development of intracardiac shunts. (c) 2007 Elsevier B.V. All rights reserved.

A low-cost 3D reconstruction system using a single-shot projection of a pattern matrix

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microbiological assay for ceftazidime injection

A simple, sensitive, and specific biodiffusion assay for the! antibacterial ceftazidime was developed using a strain of Staphylococcus epidermidis (ATCC 12228) as the test organism. Ceftazidime was measured in powder for injection at concentrations ranging from 100 to 400 mu g/mL. The calibration graph for ceftazidime was linear (r(2) = 1), and the method validation showed that it was precise (relative standard deviation = 0.415) and accurate. The results obtained by biodiffusion assay were statistically calculated by linear parallel model and by means of regression analysis and were verified using analysis of variance. It was concluded that the microbiological assay is satisfactory for in vitro quantification of the antibacterial activity of ceftazidime in pharmaceuticals.

Subconjunctival Delivery of Antibiotics in a Controlled-Release System A Novel Anti-infective Prophylaxis Approach for Cataract Surgery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fos-like immunoreactivity in central nervous system of mice simultaneously exposed to the elevated plus-maze and nociception

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)