Germicide wound pad with active, in situ, electrolytically produced hypochlorous acid

We describe a new wound dressing technology that can actively generate an inorganic germicide agent, in situ, within the wound pad. The technology provides real time control over the quantitative, spatial and temporal delivery of the germicide. The identity of the germicide is hypochlorous acid (HClO). The HClO is produced in a flexible wound pad, made of a composite of thin (micrometer scale) layers of various materials, with different electrochemical properties that enhance HClO production. Active control over the production of HClO is achieved by control of the pH and of the electric potential across the layers. The effectiveness of the Active HClO Pad (AHClOP) concept is demonstrated in a study on sterilization of E. coli in a deep wound contamination simulating gel. The performance of the AHClOP is compared with that of four commercial wound dressings. Results show that the AHClOP can sterilize throughout the gel, while the commercial dressings cannot.

Simultaneous analysis of vitamins B in pharmaceuticals and dietary supplements by capillary electrophoresis hyphenated with triple quadrupole mass spectrometry

The advanced hyphenated method based on capillary electrophoresis (CE) on-line combined with electrospray ionization (ESI) and tandem mass spectrometry (MS/MS, here triple quadrupole, QqQ) was developed and applied in pharmaceutical analysis in this work. Under the optimized CE separation (background electrolyte: 50 mmol/L formic acid with pH 2.05), ESI ionization (sheath liquid: 0.1% v/v formic acid in 50% v/v aq methanol) and QqQ detection (100-160V fragmentor voltage, 15-25eV collision energy, depending on the type of analyte) conditions, highly efficient, reproducible, accurate, sensitive (sub microg/mL LODs) and selective (each analyte was unequivocally specified by two characteristic MS signals, i.e. qualifier, quantifier) determination of vitamins B was achieved. All vitamins B, namely thiamine, riboflavin, nicotinamide, nicotinic acid, pantothenic acid, pyridoxine, biotin, folic acid and cyanocobalamine, were simultaneously determined in various dosage forms (injection solution, tablets, and effervescent tablets) within ca. 16 min. The main benefits of the proposed CE-ESI-QqQ method in comparison with the CE-UV ones are considerably enhanced sensitivity and selectivity. Other benefits are low cost, simplicity, flexibility and environmental aspects when comparing CE-ESI-QqQ with HPLC-MS. Successful validation and application of the proposed CE-ESI-QqQ method suggest its routine use in highly effective and reliable multi-drug quality control.

Determination of selenium in clinical plasma samples related to atopic dermatitis study by chronopotentiometric stripping method

Galvanostatic stripping chronopotentiometry (GSC) was developed and applied for the determination of selenium in human plasma. In this work GSC based on composite carbon electrode coated by a gold layer was optimized concerning various electrochemical parameters (coating procedure, electrolysis potential, electrolysis time, dissolution current). Along with this, the sample preparation was optimized with respect to mineralization conditions (type and concentration of decomposition agent, temperature, time). The human plasma samples mineralized in an autoclave under the optimized conditions (160 degrees C, 100 min, 22 mol/l HNO3) were appropriately diluted by background electrolyte solution (0.100 mol/l H2SO4 + 0.001 mol/l HCl) and directly analyzed by the optimized GSC method. The proposed method was characterized by excellent performance parameters, the limit of detection was 0.2 ng/ml, accuracy <5%, reproducibility <4%. The proposed method was applied for the investigation of the relationship between atopic dermatitis and selenium concentration in human plasma. Here, patients suffering from atopic dermatitis were monitored during their treatment with a pharmaceutical preparation containing inorganic selenium (Zinkosel). After six months therapy increased levels of selenium in plasma were detected in 76% of the patients with an improvement of the clinical state in 65% of the patients.

Enantiomeric purity control of levocetirizine in pharmaceuticals using anionic cyclodextrin mediated capillary electrophoresis separation and fiber-based diode array detection

The present work illustrates potential of anionic cyclodextrin (CD) mediated capillary electrophoresis (CE) separation technique coupled with on-capillary diode array detector (DAD) for highly reliable enantioselective determination of dextrocetirizine (DCET) besides its major active compound (levocetirizine, LCET) in pharmaceuticals (commercial tablets). DAD detection was utilized for the characterization of composition of each separated zone via match of corresponding tested (analyte in dosage form) and reference (standard analyte in water) UV-VIS spectrum (scanned in interval 200-800 nm) being expressed mathematically through Pearson's correlation coefficient (PCC). It was demonstrated, comparing the reference and real spectra of CET enantiomers, that the applied separation method was selective enough to produce pure (spectrally homogeneous) zones of interest without any interfering comigrating compound (PCCs values were equal or higher than 0.99). Successful validation of the proposed CE-DAD method suggests its routine use for the control of enantiomeric purity of pharmaceuticals.

Determination of amlodipine enantiomers in pharmaceuticals using capillary electrophoresis separation and diode array detection

The present work describes a capillary zone electrophoresis (CZE) separation technique coupled with on-capillary diode array detector (DAD) for highly reliable enantioselective determination of amlodipine (AML) in commercial tablets. For the separation of AML enantiomers, (2-hydroxypropyl)-beta-cyclodextrin (HP-beta-CD) was an appropriate chiral selector providing complete enantioresolution. Optimized separation conditions consisted of 50 mmol/l glycine-acetate buffer, pH 3.2, 50 mg/ml HP-beta-CD. Hydroxyethylcellulose (HEC, 0.2% w/v) served as an electroosmotic flow (EOF) suppressor in this buffer. DAD detection was used for the characterization of the composition of separated zones according to differences in corresponding UV-VIS spectra (scanned in interval 200-800 nm). It was demonstrated, comparing reference and real spectra of the analytes, that the proposed separation method was selective enough to produce pure (non-mixed, i.e. spectrally homogeneous) analyte zones without any interfering compound. Successful validation and application of the proposed CZE-DAD method suggest its routine use in enantioselective control of AML in pharmaceuticals.

Determination of dimethindene enantiomers in pharmaceuticals by capillary electrophoresis with carboxyethyl-beta-cyclodextrin

Cyclodextrin-mediated capillary zone electrophoresis in a hydrodynamically closed separation system with suppressed electroosmotic flow and UV absorbance photometric detection was developed for a high effective separation and quantitation of dimethindene enantiomers in various pharmaceutical formulations (solution, gel, capsules). The running buffer consisted of epsilon-aminocaproic acid (20 mmol/l) adjusted to pH 4.5 with acetic acid, negatively charged carboxyethyl-beta-cyclodextrin (2.5 mg/ml), serving as chiral selector, and 0.1% (w/v) methylhydroxyethylcellulose, serving as an electroosmotic flow suppressor. The proposed method was successfully validated appraising parameters of sensitivity, linearity, precision, accuracy/recovery and robustness and it is useful for routine use.

Comparison of capillary zone electrophoresis and isotachophoresis determination of dimethindene enantiomers in pharmaceuticals using charged carboxyethyl-beta-cyclodextrin as a chiral selector

Charged cyclodextrin-mediated capillary electrophoretic methods (capillary zone electrophoresis [CZE] and isotachophoresis [ITP]) in a hydrodynamically closed separation system with suppressed electroosmotic flow and UV absorbance photometric detection (for CZE) or conductivity detection (for ITP) were developed for a highly effective separation and quantitation of dimethindene enantiomers in various pharmaceutical formulations (solution, gel, capsules). Optimized electrolyte systems were based on low-mobility buffer constituents (epsilon-aminocaproic acid, beta-alanine, potassium acetate, acetic acid), negatively charged (at pH > 4.5) carboxyethyl-beta-cyclodextrin (CE-beta-CD), serving as chiral selector, and methylhydroxyethylcellulose, serving as an electroosmotic flow suppressor. Complete enantioseparations of dimethindene in the presence of low concentrations of CE-beta-CD (2.5 mg/ml in CZE, 6.0 mg/ml in ITP) clearly indicated a role of charge of this chiral selector in enantioresolution. It also outlined the potential of charged CD-derivatives as chiral selectors for various CE techniques. The proposed methods were successfully validated, appraising parameters of sensitivity, linearity, precision, accuracy/recovery, and robustness, and then, they were applied to pharmaceutical samples. Consistent results obtained by both CE methods indicate their usefulness for routine use.

[Separation of dimetinden enantiomers in drugs by means of capillary isotachophoresis]

Capillary isotachophoresis was employed to separate and determine dimethinden enantiomers in various dosage forms. Several types of chiral selectors were tested in various electrolyte systems of different composition and different pH. The optimal leading electrolyte was composed of 10 mmol/l potassium acetate and acetic acid to achieve pH 4.8 with an addition of 4 mmol/l carboxyethyl-beta-cyclodextrin as the chiral selector and 0.2% of methylhydroxyethylcellulose (m-HEC) to suppress the electroosmotic flow. The terminating electrolyte was betaalanine of a concentration of 5 mmol/l. The evaluation included the precision, correctness, linearity, robustness, and selectivity of the elaborated ITP method. The pretreatment of the sample prior to analysis consisted in the dissolution and dilution of the appropriate dimethinden-containing dosage form with demineralized water to achieve the required concentration. Such a pretreated sample was directly dosed into the apparatus.

[Isotachophoretic determination of desloratadine in tablets and syrup]

Desloratadine was determined in two dosage forms (tablets and syrup) with the use of the method of capillary isotachophoresis. Several electrolyte systems of varying composition and varying pH were tested. Two electrolyte systems were selected for the validation of the method and determination of desloratadine in real samples. In both electrolyte systems, the precision, correctness, linearity, robustness, and selectivity of the ITP method were evaluated. The pre-treatment of the sample prior to analysis consisted in dissolving and diluting the pertinent desloratadine-containing dosage form with demineralized water to the required concentration. This pre-treated sample was fed directly to the apparatus.

[Dimethindene determination in various dosage forms by means of capillary isotachophoresis]

Capillary isotachophoresis was employed to determine dimethindene in various dosage forms. Several electrolyte systems of varying compositions and varying pH were tested. For validation of the method and the determination of dimethindene in real samples (gel, drops, capsules), two electrolyte systems were selected. Precision, correctness, linearity, robustness, and selectivity of the ITP method were evaluated for both electrolyte systems. The pre-treatment of the sample prior to analysis consisted in dissolving and diluting the pertinent dosage form containing dimethindene with demineralized water to the required concentration. The sample adjusted in this way was directly dosed into the apparatus.

[Use of capillary isotachophoresis for the determination of pheniramine in granulated powders]

The method of capillary isotachophoresis was used to assay pheniramine in granulated powders. Several electrolyte systems of different composition and different pH were tested. Two electrolyte systems were selected for the validation of the method and pheniramine determination in real samples. Precision, accuracy, linearity, robustness, and selectivity of the ITP method for both electrolyte systems were evaluated. The pre-treatment of samples prior to analysis consisted in dissolving pheniramine-containing granulated powder in demineralized water and subsequent diluting with demineralized water to required concentration.

Determination of promethazine hydrochloride in pharmaceuticals by capillary isotachophoresis

Capillary isotachophoresis (ITP) in cationic regime of the separation with conductometric detection has been used for the separation and determination of promethazine hydrochloride (PRO) in commercial mass-produced pharmaceutical preparations. Several electrolyte systems of different compositions and pH were examined and the optimized ITP electrolyte system consisted of 10 mmol/l of potassium acetate adjusted to pH 4.8 with acetic acid as the leading electrolyte with electroosmotic flow (EOF) suppressing additive, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC), and 5 mmol/l of beta-alanine as the terminating electrolyte. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid, and highly reproducible assay of promethazine. The calibration graph relating the ITP zone length to concentration of the analyte was rectilinear in the range of 40-200 mg/l of the drug standard, with a coefficient of determination r(2)=0.9992. The relative standard deviation (RSD) was 1.12% (n=6) when determining 100 mg/l of PRO in standard sample. Good quantitation was obtained in short analysis time (a single analysis took 6 min). The recoveries of drug from samples were found to be 97.22% (tablets), 99.72% (injections), and 99.14% (syrup). The minimal sample pretreatment and low running cost make the proposed ITP method a good alternative to commonly used analytical methods.

Capillary zone electrophoresis determination of loratadine in tablets

A capillary electrophoretic method was developed for the determination of loratadine in pharmaceutical formulations. Capillary zone electrophoresis (CZE) separation and UV absorbance photometric detection were carried out in a 160 mm capillary tube with a 300 microm internal diameter, hydrodynamically (membrane) closed. The influences of pH, carrier cation and counter ion on the migration parameters of loratadine were studied and the following conditions were selected: 24 mmol/l glycine as a carrier cation, 1.6 mmol/l citric acid and 84 mmol/l acetic acid as counter ions at pH 3.2, 100 microA and 25 degrees C. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid and highly reproducible assay of loratadine. The determination of loratadine in tablet forms was demonstrated as an application of the method. CZE analysis was completed within 6 min. The detection limit of loratadine was 1.96 micro/mol/l at a 240 nm detection wavelength and the relative standard deviation for its determination was 0.6% for migration time and 1.1% for peak area. CZE in a hydrodynamically closed separation system, used for the first time for the analysis of loratadine, should also be convenient for complex biological sample applications, as it is easily combinable online with the purification CE modes (e.g. ITP).

Capillary isotachophoresis of cystine in urine with on-line isotachophoresis sample pretreatment

Capillary isotachophoresis (ITP) with on-line isotachophoresis sample pretreatment and conductivity detection has been proposed as a method for the separation, detection and determination of cystine present in urine. Sample pretreatment was achieved using a 90 mm FEP capillary tube with a 800 microm internal diameter. ITP separations and conductivity detection were carried out in a 160 mm capillary tube with a 300 microm internal diameter, filled with a hydrochloric acid leading electrolyte and glycine terminating electrolyte, at 50 microA and 25 degrees C. The results show that the proposed method is suitable for resolution of cystine from matrix interferents present in the urine samples and is able to detect it at 10(-4) mol/l concentrations by a universal detection technique after removal of a significant part of the anionic constituents of the sample migrating in the on-line coupled capillary isotachophoresis stack. This simple ITP procedure for monitoring cystine in urine samples requires no sample preparation. This makes it an alternative to the currently used procedures.

Separation of multicomponent mixtures of 2,4-dinitrophenyl labelled amino acids and their enantiomers by capillary zone electrophoresis

The use of capillary zone electrophoresis (CZE) for the separation of a group of 33 2,4-dinitrophenyl labeled amino acids (DNP-AA), including DNP-AA racemates, DNP-L-AA enantiomers and achiral DNP-AAs, was investigated. Alpha-, beta- and gamma-cyclodextrins (CDs) and their derivatives (hydroxypropyl derivatives of alpha-, beta- and gamma-CDs, polymeric beta-CD and 6A-methylamino-beta-cyclodextrin (MA-beta-CD)) served as complexing agents and chiral selectors in this investigation. Although native alpha- and gamma-CDs and their derivatives influenced the effective mobilities of the studied DNP-AAs in different ways, they generally failed to resolve enantiomers of the individual DNP-AAs. On the other hand, beta-CD and all of its derivatives were found to be effective in this respect. Of these, the best results were achieved with a positively charged MA-beta-CD and this chiral selector resolved enantiomers of ten DNP-AA racemates available for this study. However, a complete resolution of these enantiomers in one CZE run required that the effect of the chiral selector be complemented by complexing effects of polyvinyl pyrrolidone (PVP) or gamma-CD. Complexing and chiral recognition capabilities of MA-beta-CD combined with complexing effects of gamma-CD and PVP provided separating conditions suitable for the CZE separations of multicomponent mixtures of DNP-AAs with preserved resolutions of the enantiomers. For example, a mixture consisting of 43 DNP-AA constituents was resolved using an MA-beta-CD/gamma-CD combination with three peak overlaps.

[Occurrence of abnormal late ventricular potentials in myocardial ischemia and the determination of risk of sudden cardiac death in patients after myocardial infarct]

BACKGROUND

The crucial step in prevention of sudden cardiac death (SCD) is a method of a precise and most accessible identification of those patients with ischaemic cardiac disease (ICD), especially after MI, who are highly presumptive candidates of malign ventricular arrhythmias. The selection of individuals exposed to risk, and individual judgment of the threat to patients after MI is a complex problem. Patients after MI are endangered by reinfarction, cardiac failure, heart wall rupture and primary ventricular tachyarrhythmia. Stratification of patients exposed to a presumably higher risk of probable new coronary event and malign ventricular arrhythmia with an early decision to intervene, gains practical clinical significance. Similarly, it is important to identify also the patients after MI exposed to lower risk, who need no interventional therapeutical procedure. The cardiologic practice utilizes several examinatory procedures and tests, prevailingly of non-invasive character.

AIMS AND OBJECTIVES

The study reviews the latest information on pathophysiology and current level of clinical interpretation of non-invasive ecg procedure from the field of high-resolution electrocardiography including the late ventricular potentials (LVP). The study is aimed at: a) presentation of a review of available information from the field of electrophysiology and clinical electrocardiography and the mechanism of impact of myocardial ischaemia on the existence of high-frequency, but at the same time extremely low-amplitude potentials abnormalities in the course of QRS complex and S-T segment (LVP), b) presentation of a review on the informative value and clinical significance produced by non-invasively detected electrophysiological heterogeneity of myocardium during ischaemia, aiding the short-term and long-term prognosis judgments in patients with ICD, especially after undergoing its most serious form--myocardial infarction. Beside the group analysis the study is also aimed at individual non-invasive judgment of risk of the development of malign ventricular arrhythmias in patients with acute coronary syndromes. (Fig. 3, Ref. 41.)

Intracellular polymerization of the serpin plasminogen activator inhibitor type 2

Plasminogen activator inhibitor type 2 (PAI-2) is synthesized in two molecular forms: an intracellular, nonglycosylated form and an extracellular, glycosylated form. The bitopological distribution of PAI-2 is caused by an inefficient internal secretion signal. In addition, the secretion efficiency of PAI-2 seems to differ, depending on the cell type, differentiation state, and culture conditions. In recombinant cell clones designed for the synthesis of the secreted form of PAI-2, the fraction of secreted PAI-2 decreased with increasing expression levels. Subcellular fractionation of cell clones with higher expression levels revealed that PAI-2 accumulating in the cell was mainly associated with the organelles of the secretory pathway. Electrophoresis under nondenaturating conditions revealed that the PAI-2 retained at higher expression levels was mainly polymerized. Polymers of PAI-2 were also detected in cytosolic extracts prepared from human placenta and phorbol ester-stimulated U 937 cells, indicating that intracellular polymerization of PAI-2 may occur in the cytosols of cells that normally express PAI-2 under physiological conditions. When purified PAI-2 or cellular extracts were incubated at 37 degrees C for 24 h most of the PAI-2 protein was found to polymerize. Polymer formation was prevented by the addition of synthetic peptides with sequences corresponding to residues P2 to P14 in the reactive center loop of PAI-2 and antithrombin. These synthetic peptides also caused dissociation of prepolymerized purified PAI-2 and PAI-2 polymers in cellular extracts. Incubation with unrelated peptides of the same size had no effect on polymer formation or dissociation of preformed polymers, indicating that polymerization of PAI-2 occurs by the loop-sheet mechanism. Taken together, our data suggest that the wild-type form of PAI-2, like some natural pathological genetic variants of alpha1-antitrypsin, antithrombin, and C1 inhibitor readily polymerizes intracellularly and that polymerization may lead to a reduced secretion efficiency.

Plasminogen-activator inhibitor type 2 (PAI-2) is a spontaneously polymerising SERPIN. Biochemical characterisation of the recombinant intracellular and extracellular forms

Plasminogen-activator inhibitor type 2 (PAI-2) is a specific inhibitor of plasminogen activators (PA) that exists in an intracellular, low-molecular-mass form and a secreted, high-molecular-mass form that varies with respect to glycosylation. Here we have developed expression systems for both forms of PAI-2 and biochemically characterised the purified proteins. In order to obtain efficient secretion, we constructed an artificial signal sequence and fused it to the coding region of PAI-2. With this construct, more than 90% of PAI-2 was secreted as a glycosylated, 60-kDa molecular-mass form, but the level of expression was low and unstable. To obtain higher expression of secreted PAI-2, a novel expression vector based on the Semliki-forest-virus replicon was used. Secreted PAI-2 was purified to homogeneity and N-terminal sequence analysis showed that the artificial signal peptide was correctly removed. The intracellular, non-glycosylated form of PAI-2 was expressed in Escherichia coli and purified to homogeneity. Both the secreted and the intracellular forms of PAI-2 were found to inhibit plasminogen activators by forming SDS-resistant complexes and the second-order rate constants were similar for both forms, ranging over 2.4-2.7 x 10(6) M-1s-1 for urokinase-type PA, 2.5-2.7 x 10(5) M-1s-1 for two-chain tissue-type PA and 0.8-1.2 x 10(4) M-1s-1 for single-chain tissue-type PA. None of the purified PAI-2 forms bound to vitronectin. Circular-dichroism spectral analysis revealed that PAI-2 has a CD spectrum that resembles ovalbumin more than PA-inhibitor type 1, confirming the greater similarity between these two members of the serine-protease inhibitor family. Similar to what has been described for the Z-form of alpha 1-antitrypsin, purified PAI-2 was found to spontaneously form polymers during incubation at room temperature. Attempts to convert PAI-2 to a stable locked conformation resembling the conformation of latent PAI-1 by treatment with diluted guanidinium chloride were unsuccessful. Instead, this treatment enhanced the formation of PAI-2 polymers, possibly by the loop-sheet polymerisation mechanism described for alpha 1-antitrypsin.

The efficiency of the uncleaved secretion signal in the plasminogen activator inhibitor type 2 protein can be enhanced by point mutations that increase its hydrophobicity

Plasminogen-activator inhibitor type 2 (PAI-2) is a specific inhibitor of plasminogen activators that belongs to the serine protease inhibitor superfamily (SERPINS). PAI-2 exists in two molecular forms: an intracellular, non-glycosylated form and a secreted, glycosylated form. Like ovalbumin, PAI-2 contains an uncleaved internal secretion signal. By deletion analysis, we have mapped the secretion signal to two mildly hydrophobic regions near the NH2 terminus. We also show that both of these regions become more efficient translocation signals when their hydrophobicities are increased. The PAI-2 secretion signal provides a unique example of a signal that, by virtue of its poor efficiency, allows the synthesis of both an extracellular and an intracellular form of the protein.

Treatment of aortic arch aneurysms with deep hypothermia and circulatory arrest

A patient with an aneurysm of the aortic arch is presented. The patient underwent successful surgical correction using deep hypothermia with circulatory arrest and preserving an aortic cuff including the supra-aortic trunks to facilitate the anastomosis with the prosthesis. Technical and tactical detail are also discussed.

Absent right pulmonary artery complicating Tetralogy of Fallot

A case of tetralogy of Fallot associated with absence of the right pulmonary artery is presented. The patient underwent successful surgical correction. The embryological and clinical aspects of this patient are discussed.