Ideonella sakaiensis Can Metabolize Bisphenol A as a Carbon Source

Bisphenol A and its analogues represent a significant environmental and public health hazard, particularly affecting the endocrine systems of children and newborns. Due to the growing need for non-pathogenic biodegradation microbial agents as environmentally friendly and cost-effective solutions to eliminate endocrine disruptors, this study aimed to investigate the degradation of bisphenol A by Ideonella sakaiensis, based on its currently understood unique enzymatic machinery that is already well known for degrading polyethylene terephthalate. The present study provides novel insights into the metabolic competence and growth particularities of I. sakaiensis. The growth of I. sakaiensis exposed to bisphenol A exceeded that in the control conditions, starting with 72 h in a 70% nutrient-rich medium and starting with 48 h in a 100% nutrient-rich medium. Computational modeling showed that bisphenol A, as well as its analogue bisphenol S, are possible substrates of PETase and MHETase. The use of bisphenol A as a carbon and energy source through a pure I. sakaiensis culture expands the known substrate spectra and the species' potential as a new candidate for bisphenol A bioremediation processes.

Rapid Environmental Impact Assessment of Penicillin G in a Veterinary Product Using an Original Software Method and Monitoring by SPE-Online-UHPLC-MS/MS

Veterinary antibiotics have become a major concern due to potential environmental effects. This study presents an investigation of the exposure and environmental effects of the veterinary medicinal product in powder form, administered in the drinking water of piglets, chickens and turkeys, containing 250 mg/g penicillin G (benzylpenicillin potassium), performed according to the European Medicines Agency (EMEA) guideline and the results obtained by an analytical method based on online solid-phase extraction, ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometer (SPE-online-UHPLC-MS/MS). The study presents the determination of the environmental risk and through an original, interactive, fast software method, created on the basis of a proprietary calculation algorithm that goes through all the prescriptions and recommendations of the EMEA guide. The results demonstrated that the concentration value for penicillin G determined in surface water by SPE-online-UHPLC-MS/MS is much lower than that predicted by calculation (predictable concentration in surface water, PECsurface water = 37.66 µg/L and the concentration SPE-online-UHPLC-MS/MS = 0.032 µg/L). Both results lead to a sub-unit risk quotient (R) indicating that the treatment carried out with the considered veterinary product does not present any risk to the environment.

Flexible Investment Casting Wax Patterns for 3D-Printing: Their Rheological and Mechanical Characterizations

The mechanical and rheological characterizations of flexible investment casting patterns capable of 3D printing are reported. The wax pattern was composed of microcrystalline hydrocarbon wax (DMW7478), Piccotex 75 (a copolymer of α-methyl-styrene and vinyl toluene with a 75/25 molar ratio, respectively) and Escorene (a copolymer of ethylene and vinyl acetate with a 72/28 mass ratio, respectively). It was found that in order to obtain a wax pattern with appreciable mechanical properties, the content of the microcrystalline hydrocarbon wax in these blends should not exceed 30% (m/m). Thus, a series of patterns with 28% (m/m) wax and varying Piccotex and Escorene contents spanning from 0 to 72% (m/m) was prepared. The dependence of the dynamic viscosities of the wax patterns on the composition was described using a stretched exponential model, whereas their variations with the temperature were interpreted in terms of the Arrhenius-Guzman equation. Furthermore, the slopes of the lines fitted to the viscosity versus temperature curves at the pour point decreased linearly with the Piccotex content. Non-Newtonian changes in the shear stress with the shear rate and shear stress crystallization were observed at temperatures near the pour points. The mechanical properties were evaluated using the uniaxial tensile mode and by three-point bending experiments. It was found that the stress (σ) versus the relative elongation (ε) curves can effectively be rendered by means of the standard linear solid (SLS) viscoelastic model. In addition, it was also established that the Young's modulus varied according to a sigmoid-type curve with the piccotex content, while the yield stress decreased linearly with the concentration of Piccotex. In addition, based on the spooling suitability and printability, the patterns were rated and it was found that the most appropriate wax pattern compositions for 3D printing were those which contained 30% (m/m) and 35% (m/m) Piccotex.

Gas-Phase Interaction of Anions with Polyisobutylenes: Collision-Induced Dissociation Study and Quantum Chemical Modeling

The gas-phase interaction of anions including fluoride, chloride, bromide, iodide, ethyl sulfate, chlorate, and nitrate with polyisobutylene (PIB) derivatives was studied using collision-induced dissociation (CID). The gas-phase adducts of anions with PIBs ([PIB + anion](-)) were generated from the electrosprayed solution of PIBs in the presence of the corresponding anions. The so-formed adducts subjected to CID showed a loss of anion at different characteristic collision energies, thus allowing the study of the strength of interaction between the anions and nonpolar PIBs having different end-groups. The values of characteristic collision energies (the energy needed to obtain 50% fragmentation) obtained by CID experiments correlated linearly with the binding enthalpies between the anion and PIB, as determined by density functional theory calculations. In the case of halide ions, the critical energies for dissociation, that is, the binding enthalpies for [PIB + anion](-) adducts, increased in the order of I(-) < Br(-) < Cl(-) < F(-). Furthermore, it was found that the binding enthalpies for the adducts formed with halide ions decreased approximately with the square radius of the halide ion, suggesting that the strength of interaction is mainly determined by the "surface" charge density of the halide ion. In addition, the characteristic collision energy versus the number of isobutylene units revealed a linear dependence.

Can Nonpolar Polyisobutylenes be Measured by Electrospray Ionization Mass Spectrometry? Anion-Attachment Proved to be an Appropriate Method

Polyisobutylenes (PIBs) with different end-groups including chlorine, exo-olefin, hydroxyl, and methyl prepared from aliphatic and aromatic initiators were studied by electrospray ionization mass spectrometry (ESI-MS). Independently of the end-groups, presence or absence of aromatic initiator moiety, these PIB derivatives were capable of forming adduct ions with NO3 (-) and Cl(-) ions, thus allowing the direct characterization of these compounds in the negative ion mode of ESI-MS. To obtain [PIB + NO3](-) and [PIB + Cl](-) adduct ions with appreciable intensities, addition of polar solvents such as acetone, 2-propanol, or ethanol to the dichloromethane solution of PIBs was necessary. Furthermore, increasing both the polarity (by increasing the acetone content) and the ion-source temperature give rise to enhanced intensities for both [PIB + NO3](-) and [PIB + Cl](-) ions. Energy-dependent collision induced dissociation studies (CID) revealed that increasing the collision voltages resulted in the shift of the apparent molecular masses to higher ones. CID studies also showed that dissociation of the [PIB + Cl](-) ions requires higher collision energy than that of [PIB + NO3](-). In addition, Density Functional Theory calculations were performed to gain insights into the nature of the interactions between the highly non-polar PIB chains and anions NO3 (-) and Cl(-) as well as to determine the zero-point corrected electronic energies for the formation of [PIB + NO3](-) and [PIB + Cl](-) adduct ions.

Direct analysis in real time mass spectrometry (DART-MS) of highly non-polar low molecular weight polyisobutylenes

Low molecular weight polyisobutylenes (PIB) with chlorine, olefin and succinic acid end-groups were studied using direct analysis in real time mass spectrometry (DART-MS). To facilitate the adduct ion formation under DART conditions, NH₄ Cl as an auxiliary reagent was deposited onto the PIB surface. It was found that chlorinated adduct ions of olefin and chlorine telechelic PIBs, i.e. [M + Cl]^- up to m/z 1100, and the deprotonated polyisobutylene succinic acid [MH]^- were formed as observed in the negative ion mode. In the positive ion mode formation of [M + NH₄ ]⁺ , adduct ions were detected. In the tandem mass (MS/MS) spectra of [M + Cl]^- , product ions were absent, suggesting a simple dissociation of the precursor [M + Cl]^- into a Cl^- ion and a neutral M without fragmentation of the PIB backbones. However, structurally important product ions were produced from the corresponding [M + NH₄ ]⁺ ions, allowing us to obtain valuable information on the arm-length distributions of the PIBs containing aromatic initiator moiety. In addition, a model was developed to interpret the oligomer distributions and the number average molecular weights observed in DART-MS for PIBs and other polymers of low molecular weight. Copyright © 2015 John Wiley & Sons, Ltd.

Antioxidant and hepatoprotective activity of milk thistle (Silybum marianum L. Gaertn.) seed oil

This study has assessed the protective efficacy of

Collision-induced dissociation study of poly(2-ethyl-2-oxazoline) using survival yields and breakdown curves

Poly(2-ethyl-2-oxazoline), a synthetic polymer was analysed by mass spectrometry using different ion sources. Two distributions could be identified in the mass spectra which related to two different polymer series (one with hydrogen and hydroxyl end-groups and the other with methyl and hydroxyl end-groups). The fragmentation behaviour of the protonated oligomers was studied in a quadrupole time-of-flight mass spectrometer (MS) with electrospray, atmospheric pressure chemical ionization and direct analysis in real time soft ionization techniques. Three product ion series were identified in the MS/MS spectra independently of the ion source used. Based on the results, a mechanism was proposed for the dissociation by means of the accurate mass of the product ions, pseudo MS(3) experiments and the energy dependence of the product ion intensity, i.e. breakdown curves. The survival yield method was used to highlight the correlation between the size of the oligomers and the laboratory frame collision energy.

[Significance of arterial stiffness parameters for predicting cardiovascular mortality in hemodialysis patients: a prospective cohort study]

Previous studies demonstrated that different parameters of arterial stiffness are related to cardiovascular mortality in hemodialysis patients. The relative prognostic value of these parameters has not previously been evaluated in one cohort.

PATIENTS AND METHODS

Carotid-femoral pulse wave velocity, carotid augmentation index, carotid pulse pressure and carotid-brachial pulse pressure amplification were measured in 98 patients before and after hemodialysis. Patients were followed for a median of 29 months (1-34) and the association of these parameters with cardiovascular mortality was assessed using log-rank tests and Cox proportional hazards regressions.

RESULTS

During follow-up, 40 patients died (mortality rate 20.7/100 patient-year), of which 25 died of cardiovascular causes. Increasing pre- and postdialysis pulse wave velocity tertiles and decreasing predialysis pulse pressure amplification tertiles were significantly related to cardiovascular mortality (p-values are 0.012 and 0.011 for pre- and postdialysis pulse wave velocity, and <0.001 and 0,321 for pre- and postdialysis pulse pressure amplification, respectively). Neither the carotid augmentation index nor carotid pulse pressure was related to cardiovascular mortality. In the Cox-regression, the adjusted hazard ratios for 1 m/s higher pre- and postdialysis pulse wave velocity were 1.24 (1.07-1.44) and 1.17 (1.06-1.28), respectively. The hazard ratio for 10% lower predialysis pulse pressure amplification was 1.41 (1.03-1.92). When included in the same model, both predialysis pulse wave velocity and pulse pressure amplification remained significantly associated with cardiovascular mortality (relative risk: 1.23 [1.07-1.42] and 1.39 [1.02-1.89]).

CONCLUSION

Among different stiffness parameters, pulse wave velocity is consistently related to cardiovascular mortality, irrespective of the timing of measurement. Predialysis pulse pressure amplification seems to provide additional prognostic information.

Arterial Stiffness in Hemodialysis: Which Parameter to Measure to Predict Cardiovascular Mortality?

In previous studies, different parameters of arterial stiffness were related to cardiovascular mortality in hemodialysis patients, but their relative prognostic value has not previously been evaluated in 1 cohort. Carotid-femoral pulse wave velocity (PWV), the carotid augmentation index, carotid pulse pressure (CPP) and carotid-brachial pulse pressure amplification (AMP) were measured in 98 patients before and after hemodialysis. Patients were followed for a median of 29 months (1–34) and the association of these parameters with cardiovascular mortality were assessed using log-rank tests and Cox proportional hazards regressions. During follow-up, 25 patients died of cardiovascular causes. Increasing pre- and postdialysis PWV tertiles and decreasing predialysis AMP tertiles were significantly related to cardiovascular mortality (p = 0.012 and 0.011 for PWV, respectively; < 0.001 for AMP). Neither the carotid augmentation index nor carotid pulse pressure were related to cardiovascular mortality. The adjusted hazard ratios for 1 m/s higher pre- and postdialysis PWV were 1.24 (1.07–1.44) and 1.17 (1.06–1.28), respectively. The hazard ratio for 10% lower predialysis AMP was 1.41 (1.03–1.92). When included in the same model, both predialysis PWV and AMP remained significantly associated with cardiovascular mortality. Among different stiffness parameters, PWV is consistently related to cardiovascular mortality, irrespective of the timing of measurement. Predialysis AMP seems to provide additional prognostic information.

Self-association of bis-(α,β-d-glucopyranosyl)-polyisobutylene

In this paper, we report the structure and apparent molecular weights of bis-(alpha,beta-D-glucopyranosyl)-polyisobutylene (Gluc-PIB-Gluc) aggregates in CDCl(3) by NMR spectroscopy. Analysis of DOSY (diffusion-ordered NMR spectroscopy) experiments of a solution of Gluc-PIB-Gluc showed the presence of aggregates that were corroborated with dynamic light scattering. The structure of the aggregates was also studied by correlation spectroscopy (COSY) and nuclear Overhauser effect spectroscopy (NOESY) experiments.

Association of IgA nephropathy, hypothyroidism and hypercholesterolemia

Immunoglobulin A (IgA) nephropathy can rarely be associated with thyroid disease. We present a case of a young lady with nephrotic range proteinuria, microscopic hematuria, a creatinine clearance of 67 ml/min, biopsy proven IgA nephropathy, in whom hypercholesterolemia persisted after immunosuppressive therapy induced remission of glomerulonephritis. Fluvastatin was given but rhabdomyolysis developed. Unexpectedly, CK remained elevated following discontinuation of fluvastatin. Secondary amenorrhoea prompted endocrine work-up and hypothyroidism was diagnosed. Cholesterol, CK and TSH values became normal within 3 months on L-thyroxin therapy. The literature of the association of glomerular diseases and thyroid illness is reviewed. We would like to draw the attention to the possible association of glomerular pathologies and thyroid diseases and the importance of ruling out hypothyroidism and measuring CK level before starting statin therapy.

Serum 25(OH)-vitamin D levels and bone metabolism in patients on maintenance hemodialysis

AIMS

An increasing amount of evidence suggests that 25-hydroxy vitamin D3 (25(OH)D3) may contribute to the bone health of patients with chronic kidney disease (CKD). The underlying vitamin D status of these patients, however, has often been neglected. In a cross-sectional study we assessed the association between vitamin D status and parathyroid function, bone turnover, bone mass and structure in patients on maintenance hemodialysis.

METHODS

69 patients on maintenance hemodialysis were assessed by bone densitometry (DEXA) and quantitative bone ultrasound (QUS). Serum 25-hydroxy vitamin D3 levels, serum markers of bone turnover and clinical data were tabulated.

RESULTS

A high prevalence of potentially significant vitamin D3 deficiency was found in this patient group: 59% of the patients had a 25(OH)D3 level below 20 nmol/l. There was a significant negative correlation between serum 25(OH)D3 levels and serum intact parathyroid hormone (iPTH) (r = -0.231, p < 0.05), and this association remained significant after controlling for potential covariables. Furthermore, we show here that serum 25(OH)D3 concentration is positively correlated with bone mineral density (BMD) measured at the radius (r = 0.424, p < 0.01). Finally, we show for the first time that 25(OH)D3 levels are significantly and independently correlated with broadband ultrasound attenuation (beta = 0.262, p < 0.05) measured with calcaneal quantitative bone ultrasound (QUS) in patients with chronic renal failure.

CONCLUSION

Vitamin D3 deficiency may contribute to the impaired bone health of patients on maintenance dialysis.

Multiple charging of poly(propylene glycol) by binary mixtures of cations in electrospray

Single, double and triple charging of poly(propylene glycol) (PPG) (Mn = 1900 g/mol) in the presence of binary mixtures of cations (Li+, Na+, K+, Cs+, and NH4+) under electrospray ionization (ESI) conditions were investigated. For these studies, sodium ion was selected as the reference cation, and the resulting ion-intensities were evaluated as a function of the [Na+]/[C+] ratio (where C+ is the other cation, i.e., Li+, K+, Cs+ and NH4+). A linear relationship was found between INa+/IC+)and [Na+]/[C+] (INa+ and IC+ stand for the intensity of the singly charged PPG molecules cationized with Na+ and C+ ions, respectively). The slope of the INa+/IC+--[Na+]/[C+] plot (alpha) indicates the binding selectivity of Na+ ions to PPG chains with respect to cation C+. In the case of the doubly charged PPG chains, the INaNa2+/INaC2+ and INaC2+/ICC2+ versus [Na+]/[C+] ratio also yield straight lines with slopes of approximately alpha/2 and 2alpha, respectively (INaNa2+, INaC2+ and ICC2+ are the intensity of the doubly charged PPG chains cationized with two Na+ ions, Na+ and C+ ions, and two C+ ions, respectively). Similarly, linear dependences with the [Na+]/[C+] ratio for the corresponding intensity ratios of the triply charged PPG were found. Based on the value of alpha, the selectivity of the cations was found to increase in the order of Li+ < Cs+ approximately Na+ < K+ approximately NH4+. The observed relative ion intensities are interpreted on the basis of the solution state equilibrium between PPG and the cations. In addition, the investigations showed that the abundances of the doubly and triply charged PPG-containing mixed cations can be optimized in a simple way using the value of alpha.

Matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometric study of 2,3-dihydro-1,4-benzoxazepines

Fragmentations of the protonated adduct ions [M+H](+) of seven 1,4-benzoxazepine derivatives were studied using 'post-source decay' matrix-assisted laser desorption/ionization (PSD MALDI) and electrospray nozzle-skimmer collisionally induced dissociation (ESI-CID) mass spectrometric methods. It was found that both methods generated mainly product ions arising from the cross-ring cleavages of the benzoxazepine ring. Similar product ions were generated under MALDI and ESI conditions; however, it was observed that the loss of the alkylene unit from the N-substituted benzoxazepine, and the loss of a H(2)X molecule (where X = O or S), are more preferred under ESI conditions. Based on the experimental results a mechanism is also proposed for the fragmentation of the oxazepines studied.

Bimetallic silver-gold clusters by matrix-assisted laser desorption/ionization

Pure gold clusters (Aun+) were produced up to the cluster size of n = 100 by matrix-assisted laser desorption/ionization (MALDI). The mass spectrum of the resulting clusters showed alteration in the ion intensity at odd-even clusters size. On the other hand, intensity drops at cluster size predicted by the jellium model theory was also observed. Positively and negatively charged bimetallic silver-gold clusters were produced under MALDI conditions from the mixture of HAuCl4/silver trifluoroacetate and the 2-(4-hydroxyphenylazo)benzoic acid (HABA) matrix. A linear correlation was found between the intensity ratio of AunAgm+ to Au(n+1)Ag(m-1)+ cluster ions and the molar ratio of the gold to silver salt. It was observed that the composition and the distribution of the clusters can be varied with the molar ratio of the silver and gold salts. It was also found that the resulting cluster sizes obey the lognormal distribution.

Cationization of simple organic molecules by singly-charged Ag3+ cluster ions in matrix-assisted laser desorption/ionization mass spectrometry: metal cluster-molecule interactions

It was found earlier that under matrix-assisted laser desorption/ionization (MALDI) conditions several organic compounds which produce adduct with silver ions, are also capable of forming adducts with Ag(3)(+) cluster ions under appropriate conditions. The Ag(3)(+) cluster ion can be in situ generated under the MALDI analysis conditions from silver trifluoroacetate cationization agent in the presence of organic MALDI matrices. In this article the fragmentation of a commercial plasticizer, a peracetylated isoflavone glycoside and a pyrazolylphenyl disulfide derivative cationized with silver ions and Ag(3)(+) cluster ions are compared. It was observed that the complexes of Ag(3)(+) are less fragmented than the corresponding adduct ions with Ag(+). The presumable fragmentation channel of [M + Ag(3)(+)] is the elimination of Ag(2) units from these complexes. No significant dissociation of [M + Ag(3)(+)], into M and Ag(3)(+) takes place, indicating a tight connection between the corresponding molecule and Ag(3)(+) cluster ion. However, with a compound carrying very labile groups, such as the pyrazolylphenyl disulfide derivative, intramolecular cleavages can occur prior to significant dissociation of the Ag(3)(+) cluster ion.

Post-source decay matrix-assisted laser desorption/ionization mass spectrometric study of tetracyclic 2,3-dihydro-1,5-benzothiazepines

The fragmentation behavior of six tetracyclic 2,3-dihydro-1,5-benzothiazepine derivatives cationized with protons and silver ions under post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) conditions is reported. The protonated adduct ions decompose into several structurally important fragment ions, including substituted cyclopropane and benzohydrothiazole cations. Elimination of Ag and H and/or AgH from the silver-cationized adduct ions of these ([M+Ag](+)) compounds was observed. It was also found that [M+Ag](+) produced silver-depleted fragment ions exclusively. Based on the PSD results a fragmentation pathway is proposed for the [M+H](+) and [M+Ag](+) precursor ions.

[Comparison of interfaces between a NiCr alloy and various dental ceramics using transmission electron microscopy (TEM) and 3-point bending test]

Several methods (e.g. tensile strength, shear bond strength) have been used in testing metal-ceramic bonds. However, in the interface, structural and analytical investigations can be applied in determining the chemical and phase structure of substances making up the bond. The aim of the present study is to assess the interface between Wiron 99 (Bego) alloy and Vision (Wohlwend) VITA VMK68 (Vita), Carat (Dentsply/DeTrey) ceramic using transmission electron microscopy (TEM) and 3-point bending test. In the case of NiCr alloys, morphologically similar but structurally varying phases developed in all of the ceramics. In each case, a Cr2O3 layer consisting of small crystals (10-20 nm) was noticed with a series of underlying bubble-like amorphous inclusions. The exact three dimensional (3D) location of these structures and their relation to the glass-phase of the ceramic, as well as its role in the nanomechanical anchoring of the ceramic are still to be clarified. The values of debonding stress were 41.67 +/- 5.01 MPa, 52.89 +/- 8.06 MPa and 56.58 +/- 10.21 MPa for Carat, VITA VMK68 ceramic and Vision, respectively. These parameters do not present significant difference at p > or = 0.05 among the three types of ceramics. Based on our measurements it is highly likely that the micromorphology of interface is basically determined by the composition of the alloy while in the chemical composition of the newly developed phases the ceramic and the parameters of firing (temperature, magnitude of vacuum and firing time) play an important role. Values of cracking and morphological resemblance suggest that the superficial micromorphological and nanomorphological structures, acting as mechanical anchoring elements, play an important role in fixing the ceramic.

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric study of bis(imidazole-1-carboxylate) endfunctionalized polymers,

A detailed Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric (MALDI-TOF MS) investigation of polyethylene glycol (PEG), polypropylene glycol (PPG) and polyisobutylene (PIB) bis(imidazole-1-carboxylate) esters is reported. The MS spectra of PPG and PIBb is (imidazole-1-carboxylate) esters recorded in the reflectron mode showed the presence of two additional series of peaks compared to those recorded in the linear mode, while in the case of PEG bis(imidazole-1-carboxylate) only one additional peak series appeared in the reflectron MS spectra. These additional series were attributed to the formation of fragment ions by the loss of one and two end groups in the first field-free region of the instrument. The neutral losses for the three polymers were also supported by using the post-source decay method (PSD). The observation of decreasing mass difference between the adjacent peaks from two series of polymeric ions with the increase of oligomer mass indicates the presence of PSD ions in a reflectron MALDI spectrum. The relationship between the mass of the precursor ions and those of the PSD ions and neutral loss are also discussed.

Identification and fragmentation study of plasticizers with post-source decay matrix-assisted laser desorption/ionization mass spectrometry

A detailed investigation of the most commonly used plasticizers, such as phthalate, adipate and trimellitate esters, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and post-source decay (PSD) MALDI-TOFMS/MS is described. It is shown that PSD MALDI-TOFMS/MS is capable of unambiguous determination of the different types of plasticizers. The determination of the types of plasticizers from different PVC samples by PSD MALDI-TOFMS/MS, without the need for solvent extraction, is also demonstrated. The fragmentation mechanisms of these plasticizers cationized with protons and sodium ions are also reported.

Effects of different alkali metal ions on the cationization of poly(ethylene glycol)s in matrix-assisted laser desorption/ionization mass spectrometry: a new selectivity parameter

The cationization of poly(ethylene glycol)s, PEG 4000 and PEG 6000, under matrix-assisted laser desorption/ionization conditions was studied by using different concentration ratios of the sodium ion, as the reference ion, and another alkali metal ion (Li(+), K(+), Rb(+), Cs(+)). A linear correlation was found between the intensity ratio of the sodiated PEGs and PEGs cationized with alkali metal ions versus the initial concentration ratio of sodium and alkali metal ions. The slopes of these straight lines are proposed as a novel selectivity ratio for the ionization process. The intensity distribution of the cationized PEGs was also investigated. It was found that the cationized oligomers follow Poisson statistics. The M(n) and M(w) values were also evaluated. An explanation for the observed effects is given.

Evaluation of the Tensioday ambulatory blood pressure monitor according to the protocols of the British Hypertension Society and the Association for the Advancement of Medical Instrumentation

BACKGROUND

The validation of ambulatory blood pressure monitoring devices is necessary to obtain information on their accuracy. The objective of the present study was to evaluate the accuracy of the Tensioday oscillometric ambulatory blood pressure monitor according to the protocols of the British Hypertension Society and the Association for the Advancement of Medical Instrumentation (AAMI).

DESIGN

We followed the phases recommended by the British Hypertension Society protocol: before-use calibration, in-use assessment, after-use calibration, static device validation and report of the evaluation. However, we expanded on the protocol to accommodate features required by the AAMI.

METHOD

The accuracy of calibration of three Tensioday devices was tested before and after the in-use phase when each of three devices was performing 10 24 h sessions of ambulatory monitoring. As all three devices passed these phases, the accuracy of blood pressure measurement was tested in one arbitrarily selected device on 85 subjects for systolic and 85 for diastolic blood pressure values. This was done by comparing three sequential same-arm blood pressure readings obtained by the device with three readings obtained by two observers using standard mercury sphygmomanometer. The comparisons were carried out while resting in the seated, supine and standing positions for all subjects. The results were used to grade the performance of the device according to the British Hypertension Society protocol and to calculate the mean +/- standard deviation of the difference between the device and the observers, as required by the AAMI.

RESULTS

The Tensioday device achieved an overall grade of A for both the systolic and diastolic measurements, and had a mean difference compared with the observer-measured blood pressure of 1.4 +/- 5.3/1.0 +/- 4.7 mmHg, which satisfies the AAMI criteria for accuracy. The British Hypertension Society grading did not change when patients with low, medium, and high blood pressure were analysed separately. The AAMI accuracy criteria were fulfilled in the standing and lying positions as well.

CONCLUSION

On the basis of these results, the Tensioday ambulatory blood pressure monitoring device can be recommended for clinical use for ambulatory monitoring. The accuracy of the device needs, however, further testing in special situations, such as in pregnancy, in elderly patients and during exercise.

Fragmentation study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, using post-source decay matrix-assisted laser desorption/ionization mass spectrometry

A post-source decay matrix-assisted laser desorption/ionization mass spectrometric (PSD-MALDI-MS) study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, is reported. The fragmentations of rutin were performed by selecting the [R + Cat]+ peaks for PSD, where R represents a rutin molecule and Cat an alkali metal ion (Li+, Na+, K+). The PSD-MALDI mass spectra showed, depending on Cat, different fragmentation patterns with respect to both the quality and quantity of the fragment ions formed. The intensity of fragmentation decreased in the order Li+ > Na+ > K+. The fragmentation mechanism and an explanation for the observed differences are suggested.

[Application possibilities of dynamic laser light scattering photometry for the examination of poly(ethylene glycol) suppositories]

Status epilepticus is one of the most common neurologic emergencies in children, adolescents, and young adults. The advantage of diazepam suppository in medicinal therapy appears mainly in treatment of childhood epilepsy. A hydrophilic suppository base was investigated in solution by dynamic light scattering and results were compared to those of the membrane diffusion experiments measuring diazepam solubilization. According to the dynamic laser light scattering photometric measurements, the good solubilization effect of the macrogol mixture (5% Polysorbatum 20, 10% Macrogolum 400, 85% Macrogolum 1540) is explained by the formation of small, tight micellas. As the Polysorbatum 20 tenside resulted in the significant decrease (p < 0.05) of the formation of great micellas, its use led to the formation of small, tight, almost monodisperse micellas of 40-50 nm in the aqueous solution of the macrogol mixture.

[Fibro-osseous lesion of the central nervous system]

The case of a 53-year-old woman with headache and progressive right sided decline of visual acuity is reported. Computed tomography scans of the brain revealed multiple circumscribed foci of mineralization located over the left frontal and parietal, as well as the right central brain parenchyma. Surgical sampling of the left frontal lesion yielded a conglomerate composed of mineralized vessels, myriad of psammoma bodies, and metaplastic lamellar bone entangled within poorly cellular collagen fibers. No evidence was found of an underlying vascular malformation or tumor, nor was there evidence of parenchymal necrosis of infectious origin. On account of the organoid association of the mesenchymal elements and the mineralized moiety, the lesion was consistent with fibro-osseous lesion of the central nervous system. Also known as "calcifying pseudotumor" of the brain, the origin of this exceedingly rare condition is, as yet, unknown. By analogy, its pathogenesis is likely to involve mechanisms underlying tumoral calcinosis of soft tissues.

Visceral Aluminum Deposition In Chronic Renal Insufficiency. (Light Microscopy and X-ray Microanalysis)

Aluminum is a common element in our environment, but has been proved to be toxic, mainly in chronic renal insufficiency. Most cases of ALU intoxication occur during hemodialysis due to treatment of aluminum-containing drugs. In the present case, we describe visceral manifestations of aluminum deposition in a middle aged, multidialysed, male patient. Light and polarization microscopy examinations and X-ray microanalysis revealed amorph, extracellular aluminum deposits in various parenchymal organs causing failure of heart, lung and kidney functions. There were no anamnestic data concerning aluminum-containing drugs or occupational exposure.