bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genes expressed in the developing endocrine pancreas and their importance for stem cell and diabetes research
Authors: Wells James M. 
Published: June 2003

AbstractThe genes that regulate endocrine pancreas development, maintain adult endocrine cells, and stimulate progenitor/stem cells during regeneration remain largely unstudied. There is ample evidence that many of the genes involved in endocrine pancreas development also function in the homeostasis of the adult islet. In light of the potential benefits to diabetic research, it is surprising that there is little information about the genes expressed throughout the ontogeny of the endocrine pancreas. In the past few years, efforts have been made to establish the Endocrine Pancreas Consortium database (EPConDB), in which many of the genes expressed in the developing endocrine pancreas are in a database with a corresponding publicly available clone bank. In addition, advances in microarray technology now allow for a quantitative expression analysis of thousands of genes simultaneously, which makes it possible to generate a quantitative catalog of the genes expressed at each step of endocrine differentiation, from embryonic endoderm to mature beta cells. In this review, I will discuss how genes discovered by virtue of their role in endocrine pancreas development may function in the maintenance of pancreatic stem cells and the regeneration of islets. I will further summarize the recent advances in genomics‐based studies of the developing endocrine pancreas and will discuss how they might impact on the discovery of diagnostics and research into stem cell–based approaches for the treatment of diabetes. Copyright © 2003 John Wiley & Sons, Ltd.
Increase in adenosine A1 receptor gene expression in the liver of streptozotocin‐induced diabetic rats
Authors: Liu I. M. , Tzeng T. F. , Tsai C. C. , Lai T. Y. , Chang C. T. , Cheng J. T. 
Published: June 2003

AbstractBackgroundAdenosine A1 receptor (A1‐AR) activation can lower plasma glucose in diabetic rats lacking insulin. We investigated the change in A1‐AR gene expression in diabetic rats.MethodsThe incorporation of [U‐14C]‐glucose into glycogen was carried out to evaluate the effect of N6‐cyclopentyladenosine (CPA) on glucose utilization in vitro. The plasma glucose concentration was assessed by the glucose oxidase method. The mRNA and protein levels of A1‐AR in isolated liver were detected by Western blotting analysis and Northern blotting analysis, respectively.ResultsThe effect of CPA, an agonist of A1‐AR, on glycogen incorporation in hepatocytes isolated from streptozotocin‐induced diabetic rats (STZ‐diabetic rats) was more marked than that from the normal rats. However, similar glycogen synthesis was not modified by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), an activator of protein kinase C, in the isolated hepatocytes from both the normal and the STZ‐diabetic rats. A change in response at the receptor level can thus be considered. The mean level of liver mRNA transcripts encoding A1‐AR was increased in STZ‐diabetic rats to about 250% of that in normal rats. Exogenous insulin at a dose sufficient to normalize the plasma glucose of STZ‐diabetic rats reversed the mRNA level of A1‐AR in the liver after a four‐day treatment. Similar results were also observed in STZ‐diabetic rats that received treatment with phlorizin for four days. Moreover, the protein level of A1‐AR was higher in the liver of STZ‐diabetic rats than that in the normal rats. Similar treatment with exogenous insulin or phlorizin reversed the elevated protein level of A1‐AR in the liver of STZ‐diabetic rats to near the normal level. Therefore, correction of hyperglycemia in STZ‐diabetic rats can reverse the higher gene expression of A1‐AR in liver.ConclusionsThe obtained results suggest that an increase in plasma glucose is responsible for the higher gene expression of A1‐AR in the liver of STZ‐diabetic rats. Copyright © 2003 John Wiley & Sons, Ltd.
Recall of severe hypoglycaemia and self‐estimated state of awareness in type 1 diabetes
Authors: Pedersen‐Bjergaard Ulrik , Pramming Stig , Thorsteinsson Birger 
Published: June 2003

AbstractBackgroundThe ability of people with insulin‐treated diabetes to remember severe hypoglycaemia and the consistency of their self‐estimated awareness of hypoglycaemia are not well documented but are important in clinical practice. The aim of this study is to assess recall of severe hypoglycaemia in patients with type 1 diabetes and to evaluate the feasibility of a simple method for clinical classification of the awareness of hypoglycaemia.MethodsA one‐year prospective study was performed on a cohort of patients with type 1 diabetes (n = 230). The rate of severe hypoglycaemia reported retrospectively at the end of the study was compared to the prospectively recorded rate during the study period. Self‐estimated awareness was explored in questionnaires at baseline and at the end, and assessments were evaluated by the occurrence of severe hypoglycaemic episodes.ResultsAlmost 90% of the participants correctly recalled whether they had had severe hypoglycaemia. However, those with high prospectively recorded numbers had incomplete recall, resulting in a 15% underestimation of the overall rate. On the basis of the answer to the question ‘Do you recognise symptoms when you have a hypo?’, the population was classified into three groups: 40% with normal awareness, 47% with impaired awareness and 13% with unawareness. The groups with impaired awareness and unawareness had 5.1 and 9.6 times higher rates of severe hypoglycaemia, respectively, compared to the group with normal awareness (p < 0.001).ConclusionPeople with type 1 diabetes generally remember severe hypoglycaemic episodes during a one‐year period. A simple method is proposed for classifying the state of awareness of hypoglycaemia in clinical practice. Copyright © 2003 John Wiley & Sons, Ltd.
Current Awareness in Geriatric Psychiatry
Authors:   John Wiley & Sons, Ltd.
Published: June 2003

AbstractIn order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of geriatric psychiatry. Each bibliography is divided into 9 sections: 1 Books, Reviews & Symposia; 2 General; 3 Assessment; 4 Epidemiology; 5 Therapy; 6 Care; 7 Dementia; 8 Depression; 9 Psychology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted
Preparation of affinity carriers for the study of binding properties of aspartic proteinases
Authors: Kučerová Zdenka , Tichá Marie 
Published: June 2003

AbstractWe have chosen aromatic amino acids and their derivatives as ligands for the affinity chromatography of aspartic proteinases (pepsins and pepsinogens). The following ligands were used: L‐tyrosine, L‐phenylalanine, tyramine, and N‐acetyl‐L‐phenylalanine, and their iodinated derivatives (mono‐ and di‐substituted) with free or blocked amino group. Two types of reactions were used for coupling ligands to Sepharose activated with divinyl sulfone (DVS): via amino group or via carboxyl group. Ligands with free amino group were directly coupled to the activated matrix (L‐tyrosine, 3‐iodo‐L‐tyrosine, 3,5‐diiodo‐L‐tyrosine, L‐phenylalanine, 4‐iodo‐L‐phenylalanine, tyramine); ligands with blocked amino group (N‐acetyl‐L‐phenylalanine, BOC‐L‐tyrosine, BOC‐3,5‐diiodo‐L‐tyrosine; BOC: tert‐butoxy carbonyl) were coupled to Sepharose containing linked ethylenediamine using the carbodiimide reaction. Alternatively, ethylenediamine was bound to free carboxyl croup using the same reaction and these ligand derivatives reacted with divinyl sulfone activated Sepharose. The prepared affinity carriers were used to study the binding properties of porcine pepsin and pepsinogen.
Determination of total oncopterin, neopterin and biopterin in human urine by high performance liquid chromatography with solid phase extraction
Authors: Tomandl Josef , Tallova Jaroslava , Tomandlova Marie , Palyza Vladimir 
Published: June 2003

AbstractA new, sensitive method for the determination of oncopterin, biopterin, and neopterin in human urine has been developed using SPE with 6,7‐dimethylpterin as internal standard and gradient HPLC with fluorescence detection. SPE was tested for the pre‐treatment of urine samples on different types of sorbents (strong ion exchange resins, polar adsorbents, and reversed‐phase sorbents). RP‐SPE with subsequent evaporation of eluate has been found to be the most appropriate. The extraction efficiency exceeded 95% for all selected pterins. The extracted pterins were subsequently analyzed on a Purospher RP‐18 RP column. The LOD of oncopterin was 1.43 nmol/L of urine. The intra‐day and inter‐day imprecision at a physiological oncopterin concentration never exceeded 10%. The potential of this method was tested using urine samples of healthy volunteers and cancer patients without methotrexate therapy.
Comparison of enantioseparation of selected benzodiazepine and phenothiazine derivatives on chiral stationary phases based on β‐cyclodextrin and macrocyclic antibiotics
Authors: Tesařová Eva , Bosáková Zuzana 
Published: June 2003

AbstractEnantioselective separation of some phenothiazine and benzodiazepine derivatives was studied on six different chiral stationary phases (CSPs) in HPLC. Selected CSPs, with respect to the structure of the separated compounds, were either based on β‐cyclodextrin chiral selectors – underivatized β‐cyclodextrin and hydroxypropyl ether β‐cyclodextrin, or on macrocyclic antibiotics – vancomycin, teicoplanin, teicoplanin aglycone, and ristocetin A. Measurements were carried out in a reversed‐phase separation mode. The influence of mobile phase composition on retention and enantioseparation was studied. Benzodiazepines could be enantioresolved with almost all the chiral stationary phases used, except for the vancomycin‐bonded CSP. Peak coalescence of oxazepam and lorazepam was observed if separation was carried out at laboratory temperature. Reduced temperature was required in some instances in order to avoid the on‐column racemization. Separation systems composed of teicoplanin‐bonded CSP and buffer‐methanolic or pure methanolic mobile phases were shown to be suitable even for preparative purposes due to high resolution values of the enantiomers. Enantioseparation of phenothiazine derivatives was more difficult to achieve but it was successful, at least partly, also with both types of the CSPs used (except for levomepromazine).
Determination of oxalate in beer by zone electrophoresis on a chip with conductivity detection
Authors: Masár Marián , Žúborová Mária , Kaniansky Dušan , Stanislawski Bernd 
Published: June 2003

AbstractThe use of a poly(methylmethacrylate) capillary electrophoresis chip, provided with a high sample load capacity separation system (a 8500 nL separation channel combined with a 500 nL sample injection channel) and a pair of on‐chip conductivity detectors, for zone electrophoresis (ZE) determination of oxalate in beer was studied. Hydrodynamic and electroosmotic flows of the solution in the separation compartment of the chip were suppressed and electrophoresis was a dominant transport process in the separations performed on the chip. A low pH of the carrier electrolyte (3.8), implemented by aspartic acid and bis‐tris propane, provided an adequate selectivity in the separation of oxalate from anionic beer constituents and, at the same time, also a sufficient sensitivity in its conductivity detection. Under our working conditions, this anion could be detected at a 0.5 μmol/L concentration also in samples containing chloride (a major anionic constituent of beer) at a 1800 higher concentration. Such a favorable analyte/matrix concentration ratio made possible accurate and reproducible [typically, 2–5% relative standard deviation (RSD) values of the peak areas of the analyte in dependence on its concentration in the sample] determination of oxalate in 500 nL volumes of 20–50‐fold diluted beer samples. Short analysis times (about 200 s), minimum sample preparation, and reproducible migration times of this analyte (0.5–1.0% RSD values) were characteristic for ZE on the chip.
Selective determination of famotidine in human plasma by high performance liquid chromatography in alkaline media with solid phase extraction
Authors: Anzenbacherová Eva , Filipová Karolina , Nobilis Milan , Anzenbacher Pavel 
Published: June 2003

AbstractA new method is described for the determination of famotidine by solid phase extraction from alkalinized human plasma followed by reversed phase (RP) HPLC in acetonitrile/alkaline buffer with molsidomine as an internal standard. Different acetonitrile/aqueous buffer mobile phases as well as various RP columns were used. Alkaline medium allowed the limit of quantitation to be lowered to 5 ng/mL of plasma as the famotidine gives more intense absorption at about 286 nm (at pH values higher than 7). Moreover, work in alkaline media and at this wavelength is highly selective as peaks corresponding to impurities present in most samples are well separated. A method using a mildly alkaline mobile phase (acetonitrile/10 mM phosphate with 10 mM 1‐heptanesulphonic acid, pH 7.5) was successfully used for determination of famotidine in human plasma in a pharmacokinetic study.
High performance liquid chromatography and capillary electrophoresis determination of sanguinarine in biological matrices
Authors: Kosina Pavel , Ševčík Juraj , Modrianský Martin , Gavenda Aleš , Bednář Petr , Barták Petr , Walterová Daniela , Ulrichová Jitka 
Published: June 2003

AbstractHPLC and CE methods were employed to determine the quaternary benzo[c]phenanthridine alkaloid sanguinarine in biological matrices (rat hepatocytes, human gingival fibroblasts, feed, porcine faeces, body fluids and tissues). HPLC was carried out on a C18 column using gradient elution and ion pairing techniques with 1‐heptanesulfonic acid as ion pairing agent under acidic conditions. The detection limit for fluorimetric detection at λex = 327 nm and λem = 577 nm was 3 nM sanguinarine. CE analyses were performed in 50 mM phosphate‐Na buffer pH 2.5, with 150 mM SDS used for pre‐concentration by the sweeping effect. This experimental configuration allows injecting the total capillary length with sanguinarine sample. The detection limit for UV detection at 285 nm was 12 nM. Both methods are suitable for analysing submicromolar quantities of sanguinarine in biological materials. The HPLC method is more sensitive than CE because it uses fluorescence detection.
Analysis of 3‐quinuclidinol derivatives by capillary electrophoresis
Authors: Bednář Petr , Barták Petr , Lemr Karel , Ševčík Juraj , Stránský Zdeněk 
Published: June 2003

AbstractCapillary electrophoresis with indirect UV detection was applied to the analysis of a mixture of 3‐quinuclidinol and its four quaternary derivatives (N‐methyl, N‐ethyl, N‐propyl, and N‐isopropyl derivative). 10 mM imidazole acetate buffer, pH = 4.0 offers suitable detection sensitivity (LOD = 1 μmol L–1) and permits separation of the mixture except for the pair 3‐quinuclidinol–N‐methyl derivative. The separation of all analytes was achieved on addition of 15 mmol L–1 β‐cyclodextrin or 25% (w/w) polyethylene glycol 2000 to the background electrolyte. The optimized method was employed for the analysis of pond water spiked with these analytes. Actual ionic mobilities of the studied compounds were measured using mobility standards (potassium, sodium, tetramethyl‐ and tetrabutylammonium). The migration index was derived as another identification parameter based on migration data and the precision of the obtained values is discussed in brief.
Separation of diastereomers of phosphinic pseudopeptides by capillary zone electrophoresis and reverse phase high‐performance liquid chromatography
Authors: Koval Dušan , Kašička Václav , Jiráček Jiři , Collinsová Michaela 
Published: June 2003

AbstractCapillary zone electrophoresis (CZE) and reverse phase high‐performance liquid chromatography (RP‐HPLC) were used for separation of diastereomers of phosphinic pseudopeptides in achiral separation media. A set of phosphinic pseudopeptides, i. e. peptides with one peptide bond substituted by phosphinic acid moiety ‐PO2–‐CH2‐ derived from the structure N‐Ac‐Val‐AlaB(‐CH2)Leu‐His‐NH2 synthesized as a mixture of four diastereomers was used. Separations of diastereomers by CZE were carried out in Tris‐phosphate background electrolytes in the pH range 1.1–3.2 and at least partial separation of the four diastereomers of each pseudopeptide was achieved. A routinely used RP‐HPLC method (C18‐silica column and water/acetonitrile/trifluoroacetic acid mobile phase) was also capable of resolving the diastereomers. In addition, since individual diastereomers of majority of the pseudopeptides were isolated by RP‐HPLC it was possible to check the purity of these RP‐HPLC separated diastereomers and to compare the migration order of the diastereomers in CZE with their elution order in RP‐HPLC. The results obtained by CZE and RP‐HPLC demonstrate a complementarity of both methods in analysis and separation of phosphinic pseudopeptides including their diastereomers.
Investigation of the separability of thaumatin by capillary electrophoresis
Authors: Vespalcová Milena , Gregorová Daniela 
Published: June 2003

AbstractThe electrophoretic behaviour of the highly basic protein thaumatin was explored in strongly acid (pH 2) and mildly acid (pH 4.5) separation systems using both bare and coated fused silica capillaries. The separation selectivity for thaumatin I, thaumatin II, and for other sample constituents was insufficient for their baseline separation at pH 2 in an uncoated capillary because the separation efficiency was markedly lower than is common in the electrophoretic separations of proteins. A separation selectivity higher by up to one order of magnitude has been reached at pH 4.5. A pronounced asymmetry of zones, which impaired resolution at this pH, was effectively suppressed by coating of the capillary wall with a polymer. In fact, adsorption on the capillary coating always plays a contributory role whenever a good separation of thaumatin constituents is attained. This indicates that electrochromatographic separation systems based on capillaries coated with the layer of either cationic or hydrophilic uncharged polymer hold promise for the development of methods for thaumatin analysis.
Analysis of phenolic acids in plant materials using HPLC with amperometric detection at a platinum tubular electrode
Authors: Jirovský David , Horáková Daniela , Kotouček Milan , Valentová Kateřina , Ulrichová Jitka 
Published: June 2003

AbstractThe suitability of a simple amperometric platinum tubular detector for HPLC analysis of selected phenolic acids in yacon (Smallanthus sonchifolius, Asteraceae) is reported. The detector offers good overall limits of detection for the phenolic acids of interest. Three different types of extracts from yacon leaves were analyzed and compared with respect to their content of phenolic acids. Caffeic acid was found in all yacon extracts, whereas the content of chlorogenic acid depends more on the extraction procedure used. It has been demonstrated that no complicated and sophisticated equipment is needed and HPLC with amperometric detection seems to be a very useful technique for analysis of plant extracts containing phenolic acids.
Direct determination of valproate in serum by zone electrophoresis–isotachophoresis on a column‐coupling chip
Authors: Ölvecká Eva , Koníková Michaela , Grobuschek Nina , Kaniansky Dušan , Stanislawski Bernd 
Published: June 2003

AbstractA feasibility study was performed using zone electrophoresis (ZE) coupled on‐line with isotachophoresis (ITP) sample pretreatment on a poly(methyl methacrylate) column‐coupling chip with integrated conductivity detection for direct determination of drugs in serum. Valproic acid (an antiepileptic drug), having a therapeutic range of 0.35–0.69 mmol/L (50–100 mg/L), was a test analyte while reference serum samples served as proteinaceous matrices. ITP provided in the ITP‐ZE combination a multitask sample pretreatment: (1) separation of the analyte from the serum matrix and its concentration into a narrow ITP band, (2) removal of the matrix constituents migrating in the ITP stack from the separation compartment of the chip, (3) ITP stacking of the drug released on a continuous electrophoretic decomposition of the drug‐protein complex. A high sample loadability, closely linked with the use of ITP in the first separation stage, made it possible to inject diluted serum samples with the aid of a 0.95 μL sample channel of the chip. Consequently, a 1–2 μmol/L concentration limit of quantitation for valproate from the response of the conductivity detector in the ZE stage of the combination was reached. The drug could be reliably determined in less than 10 minutes also in instances when its concentration in serum was below the lower value of the therapeutic range. 90–94% recoveries of valproate from serum samples were obtained in its direct ITP‐ZE determination when the filtration of the diluted serum (a 0.45 μm pore size filter) was the only pre‐column sample handling operation. No disturbances attributable to the precipitation of proteins from the loaded samples in the chip channels were detected.
Synthesis of New Polymethyloxazoline Hydrogels by the “Macroinitiator” Method
Authors: Rueda Juan , Suica Raúl , Komber Hartmut , Voit Brigitte 
Published: June 2003

AbstractNew polymethyloxazoline hydrogels are synthesized by the cationic ring‐opening copolymerization of 2‐methyl‐2‐oxazoline and 2,2′‐tetramethylenebis(2‐oxazoline), using random copolymers of chloromethylstyrene and methyl methacrylate, or of chloromethylstyrene and styrene as macroinitiators. The synthesis is carried out in benzonitrile at 110 °C in the presence of potassium iodide, which activates the chloromethyl group as initiating functionality. In general, the hydrogels are obtained very rapidly, with a yield of between 42 and 95 wt.‐%. Besides its initiating function, the macroinitiator also provides the possibility of introducing heterogeneity into the hydrogel structure by forming rigid hydrophobic domains. The hydrogel structures were characterized by high‐resolution magic angle spinning NMR spectroscopy, and their solvent absorption capacity was determined by swelling experiments in solvents of different polarity. The hydrogels showed a maximal swelling degree of 18 g of water and 40 g of methanol, respectively, per gram of the hydrogel.
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Synthesis and Properties of Hydrophilic Polymers, 10
Authors: Pizarro Guadelupe del C. , Marambio Oscar G. , O Mario Jeria , Geckeler Kurt E. 
Published: June 2003

AbstractWater‐soluble poly[(N‐maleoylglycine)‐co‐(hydroxyethyl methacrylate)] was employed for the separation of a series of metal ions in the aqueous phase using the liquid‐phase polymer‐based retention method. The method is based on the retention of inorganic ions by this polymer in conjunction with membrane filtration and subsequent separation of low‐molecular‐mass species from the polymer complex formed. It is shown that the polymer can bind several metal ions in aqueous solution at pH 3, 5, and 7, for example Cr(II), Co(II), Zn(II), Ni(II), Cu(II), Cd(II), Pb(II) inorganic ions. The interaction of the inorganic ions with the hydrophilic polymer was determined as a function of pH and filtration factor. The water‐soluble polymeric reagent with strong metal‐complexing properties was synthesized and used to separate complexed from non‐complexed ions in the homogeneous phase. The polymer exhibited high retention capability at pH 5 and 7. It was characterized by elemental analysis, FT‐IR, 1H NMR, and 13C NMR spectroscopy, as well as by thermogravimetry. Additionally, viscosimetric measurements of the copolymer were performed at different pH values.
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