bluuebunny/crossref_metadata_2025 huggingface dataset:
Autologous bone versus calcium‐phosphate ceramics in treatment of experimental bone defects
Authors: Bloemers Frank W. , Blokhuis Taco J. , Patka Peter , Bakker Fred C. , Wippermann Burkhard W. , Haarman Henk J.Th.M.
Published: July 2003

Autologous bone grafting is currently considered the treatment of choice for correction of large bone defects. However, to avoid morbidity associated with autologous bone harvesting many artificial bone‐substitute materials have been developed over the years. A new generation of resorbable materials is emerging, with promising results so far. In order to investigate the possibility to use one of these new materials as an alternative with better results than hydroxyapatite, an experimental study was performed. A new resorbable calcium phosphate particles and paste forms, the latter of which hardens in situ after application. In 28 sheep, a 3‐cm segmental tibial defect was made and intramedullary fixed by an interlocking nail. Twelve weeks after defect filling, radiological, biomechanical, and histological examinations were performed. Mean radiographic and biomechanical tests results were compared with the Mann‐Whitney test. Significance was set at p < 0.05. Radiographically, the resorbable paste group performed better than all other groups. Biomechanical investigations showed a higher torsional stiffness (p = 0.049) for the resorbable calcium‐phosphate paste group in comparison with autologous bone. On histological examination, no adverse effects were observed in the calcium‐phosphate groups. Resorbtion by osteoclasts was seen in the resorbable implants. In conclusion, the current study shows an advantageous radiological and mechanical outcome for resorbable calcium phosphates. This indicates that these new materials might be a potential alternative for autologous bone grafting in humans. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 526–531, 2003
Enzymatic synthesis of l‐tryptophan and 5prime‐hydroxy‐l‐tryptophan labeled with deuterium and tritium at the alpha‐carbon position
Authors: Boroda E. , Rakowska S. , Kański R. , Kańska M.
Published: July 2003

The enzymatic synthesis of l‐tryptophan and its derivative 5′‐hydroxy‐l‐tryptophan labeled with deuterium and tritium at the α‐carbon position is reported. The mixture containing S‐methyl‐l‐cysteine, indole or 5‐hydroxyindole dissolved in deuteriated or tritiated water has been converted to [2‐2H]‐l‐tryptophan, [2‐3H]‐l‐tryptophan, 5′‐hydroxy‐[2‐2H]‐l‐tryptophan, and 5′‐hydroxy‐[2‐3H]‐l‐tryptophan, respectively, in a one‐pot reaction using the enzyme tryptophanase. The same reaction carried out in heavy water with THO added yielded either doubly labeled [2‐2H/3H]‐l‐tryptophan or 5′‐hydroxy‐[2‐2H/3H]‐l‐tryptophan. Copyright © 2003 John Wiley & Sons, Ltd.
A general method for the fluorine‐18 labelling of fluoroquinolone antibiotics
Authors: Langer Oliver , Mitterhauser Markus , Wadsak Wolfgang , Brunner Martin , Müller Ulrich , Kletter Kurt , Müller Markus
Published: July 2003

Fluoroquinolones are an important class of antibiotic agents with a broad spectrum of antibacterial activity. Labelling of fluoroquinolones with fluorine‐18 is of interest for the performance of pharmacokinetic measurements and the visualization of bacterial infections in humans with positron emission tomography. A two‐step radiosynthetic pathway to prepare fluorine‐18‐labelled ciprofloxacin (1‐cyclopropyl‐6‐[18F]fluoro‐1,4‐dihydro‐4‐oxo‐7‐(1‐piperazinyl)‐quinoline‐3‐carboxylic acid) has previously been developed. In the present work this approach was applied to the preparation of the structurally related compounds [18F]norfloxacin (1‐ethyl‐6‐[18F]fluoro‐1,4‐dihydro‐4‐oxo‐7‐(1‐piperazinyl)‐quinoline‐3‐carboxylic acid) and [18F]pefloxacin (1‐ethyl‐6‐[18F]fluoro‐1,4‐dihydro‐7‐(4‐methyl‐1‐piperazinyl)‐4‐oxo‐quinoline‐3‐carboxylic acid). The first step of the radiosynthesis consisted of a 18F for 19F exchange reaction on a 7‐chloro‐substituted precursor molecule, followed by coupling reactions with the amines piperazine or 1‐methylpiperazine. Starting from 51–58 GBq of [18F]fluoride 1.9–2.0 GBq of [18F]norfloxacin or [18F]pefloxacin, ready for intravenous injection, could be obtained in a synthesis time of 130 min (3.5–3.8% overall radiochemical yield). Moreover, the preparation of [18F]levofloxacin ((‐)‐(S)‐9‐[18F]fluoro‐2,3‐dihydro‐3‐methyl‐10‐(4‐methyl‐1‐piperazinyl)‐7‐oxo‐7H‐pyrido[1,2,3‐de]‐1,4‐benzoxazine‐6‐carboxylicacid) was attempted but failed to afford the desired product in practical amounts. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis of 1‐[4‐(m‐tolyl)amino‐6‐quinazolinyl]‐3‐[14C]‐methyl triazene: a radiolabeled probe for the combi‐targeting concept
Authors: Matheson Stephanie L. , Mzengeza Shadreck , Jean‐Claude Bertrand J.
Published: July 2003

The synthesis of 1‐[4‐(m‐tolyl)amino‐6‐quinazolinyl]‐3‐[14C]‐methyl triazene (SMA41) is described. This triazene was designed to be hydrolyzed under physiological conditions to N4‐m‐tolyl‐quinazoline‐4,6‐diamine (SMA52), a moderate inhibitor of the epidermal growth factor receptor (EGFR) and the DNA alkylating species [14C]‐methyldiazonium. A radiolabeled probe was needed to test the hypothesis that in situ hydrolysis of SMA41 may induce alkylation of the ATP binding site of EGFR. 14C‐SMA41 was obtained with a radiochemical yield of 21% and a specific activity of 54.6 mCi/mmol, as determined by HPLC quantitation and scintillation counting. Radio‐TLC analyses showed 98% radiochemical purity. Copyright © 2003 John Wiley & Sons, Ltd.
A novel probe for imaging amyloid‐β: Synthesis of F‐18 labelled BF‐108, an Acridine Orange analog
Authors: Shimadzu Hiroshi , Suemoto Takahiro , Suzuki Masako , Shiomitsu Tsuyoshi , Okamura Nobuyuki , Kudo Yukitsuka , Sawada Tohru
Published: July 2003

The synthesis of 3‐(2‐[18F]fluoroethyl)ethylamino‐6‐diethylaminoacridine ([18F]BF‐108), a potential positron‐labelled probe for imaging amyloid‐β is described. The precursor tosylate derivative was fluorinated with [18F]KF/ Kryptofix 222 in acetonitrile, and the crude product was purified by semi‐preparative HPLC to give the radiolabelled BF‐108. The radiochemical purity was >95% and the maximum specific activity was 33.9 TBq/mmol at the end of the synthesis (EOS). The synthesis time was 130 min from the end of bombardment (EOB). Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis of tritium labelled mecillinam
Authors: Frederiksen Søren Melsing , Grue‐Sørensen Gunnar
Published: July 2003

The potent β‐lactam antibiotic mecillinam has successfully been labelled with tritium. 2,3,4,7‐Tetrahydro‐1H‐azepin‐1‐carbaldehyde was formed in a ring‐closing metathesis reaction and then condensed with trimethylsilyl protected penicillanic acid to give dehydro‐mecillinam. Pd/C catalysed tritiation then gave [3H2]‐mecillinam (6‐β (([3,4‐3H2]hexahydro‐1H‐azepin‐1‐yl)methyleneamino)penicillanic acid) with a radiochemical purity of 96% and a specific activity of 24 Ci/mmol. Copyright © 2003 John Wiley & Sons, Ltd.
Interannual and seasonal variability of modelled soil moisture in Oklahoma
Authors: DeLiberty Tracy L. , Legates David R.
Published: July 2003

The temporal variability of soil moisture is examined for Oklahoma, where diverse land surface, soils, and precipitation regimes exist. Using readily available meteorological, vegetation, and soils data, a hydrologic model was used to estimate daily soil moisture at 258 evaluation locations for the 30 year period from 1 January 1962 through 31 December 1991. A geographic information system (GIS) was used for the analysis, to take advantage of its powerful analysis capabilities and visualization tools. Results document the long‐term average soil moisture conditions, the variability that occurred during this 30 year period and the temporal scale of soil moisture variability for Oklahoma. On average, the soil moisture conditions in both winter and spring in Oklahoma are about 70% of field capacity and decrease to below 30% during the summer. Thus, the seasonal cycle is pronounced, although periods of wetter and drier conditions are evident. Overall, the period from 1962 through to early 1967, 1970–72, and 1976 through to 1981 were drier than the long‐term average soil moisture conditions. By contrast, wetter soil moisture conditions prevailed in late 1972 through to early 1975 and 1985 to the early months of 1988, where winter and spring soil moisture values often exceeded the long‐term average. An empirical estimate of the temporal consistency in soil moisture over Oklahoma is 53 days (1.8 months), and the amount of variance explained by the soil moisture (red noise) signal is 86%. No significant seasonal differences in the temporal autocorrelation were observed. Copyright © 2003 Royal Meteorological Society
A 10 year cloud climatology over Scandinavia derived from NOAA Advanced Very High Resolution Radiometer imagery
Authors: Karlsson Karl‐Göran
Published: July 2003

Results from a satellite‐based method to compile regional cloud climatologies covering the Scandinavian region are presented. Systematic processing of multispectral image data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) instrument has been utilized to provide monthly cloud climatologies covering the period 1991–2000. Considerable local‐scale variation of cloud amounts was found in the region. The inland Baltic Sea and adjacent land areas exhibited a large‐amplitude annual cycle in cloudiness (high cloud amounts in winter, low cloud amounts in summer) whereas a weak‐amplitude reversed annual cycle (high cloud amounts with a weak maximum in summer) was found for the Scandinavian mountain range. As a contrast, conditions over the Norwegian Sea showed high and almost unchanged cloud amounts during the course of the year. Some interesting exceptions to these patterns were also seen locally. The quality of the satellite‐derived cloud climatology was examined through comparisons with climatologies derived from surface cloud observations, from the International Satellite Cloud Climatology Project (ISCCP) and from the European Centre for Medium‐range Weather Forecasts ERA‐40 data set. In general, cloud amount deviations from surface observations were smaller than 10% except for some individual winter months, when the separability between clouds and snow‐covered cold land surfaces is often poor. The ISCCP data set showed a weaker annual cycle in cloudiness, generally caused by higher summer‐time cloud amounts in the region. Very good agreement was found with the ERA‐40 data set, especially for the summer season. However, ERA‐40 showed higher cloud amounts than SCANDIA and ISCCP during the winter season. The derived cloud climatology is affected by errors due to temporal AVHRR sensor degradation, but they appear to be small for this particular study. The data set is proposed as a valuable data set for validation of cloud description in numerical weather prediction and regional climate simulation models. Copyright © 2003 Royal Meteorological Society
Estimating extreme dry‐spell risk in the middle Ebro valley (northeastern Spain): a comparative analysis of partial duration series with a general Pareto distribution and annual maxima series with a Gumbel distribution
Authors: Vicente‐Serrano S. M. , Beguería‐Portugués S.
Published: July 2003

This paper analyses a 50 year time series of daily precipitation in a region of the middle Ebro valley (northeastern Spain) in order to predict extreme dry‐spell risk. A comparison of observed and estimated maximum dry spells (50 year return period) showed that the generalized Pareto (GP) distribution combined with partial duration series (PDS) gives better results than the Gumbel distribution fitted to annual maximum series. Indeed, the classical Gumbel approach underestimated the empirical duration of dry spells. The PDS–GP approach was successfully applied in the study of extreme hydro‐climatic variable values. The results reported here could be applied in estimating climatic drought risks in other geographical areas. Copyright © 2003 Royal Meteorological Society
Determination of cholesterol oxides content in milk products by solid phase extraction and gas chromatography‐mass spectrometry
Authors: Calvo María V. , Ramos Lourdes , Fontecha Javier
Published: July 2003

A method for quick and reliable analysis of cholesterol oxidation products (COPs) in dairy products has been developed. After lipid extraction, fat was transesterified under mild conditions to avoid degradation of the target compounds. Isolation of the COPs studied from other components in the lipid fraction was carried out on an aminopropyl SPE cartridge. Finally, analytes were analysed by GC‐MS without derivatisation. The method developed provides high specificity and good sensitivity, allowing the direct and unambiguous determination of the underivatized COPs investigated. Application of the method to dairy food analysis revealed the presence of COPs in powder milks and milk‐based infant formulas commercially available in Spain, showing that attention should be focused on reduction of cholesterol oxidation levels during both the processing and the storage of these types of foodstuffs.
Determination of tribromophenol and pentachlorophenol and its metabolite pentachloroanisole in Asparagus officinalis by gas chromatography/mass spectrometry
Authors: Mardones Claudia , Palma Julie , Sepúlveda Carlos , Berg Alex , von Baer Dietrich
Published: July 2003

A GC‐MS method was developed and optimized for simultaneous determination of pentachlorophenol (PCP), 2,4,6‐tribromophenol (TBP), and pentachloroanisole (PCA) residues in the edible part of Asparagus officinalis. For this purpose, two procedures were evaluated: the direct separation of PCP, TBP, and PCA and the separation of acetyl‐PCP, acetyl‐TBP, and non‐acetylated PCA. Better sensitivity and quantitative results, especially for PCP, were obtained after acetylation. The residues of PCP and TBP were extracted as phenolates and acetylated in a carbonate solution. Acetylated compounds were extracted by liquid‐liquid extraction with hexane, while PCA was directly leached with this solvent. The proposed method allows the rapid quantification of traces of PCP, TBP, and PCA in a concentration ranging between 1.0 and 8.0 ng mL–1 in solution (corresponding to 0.3 and 8.0 μg kg–1 in asparagus). In this concentration range, typical recoveries for PCA, TBP, and PCP from asparagus samples were 59%, 86%, and 97% respectively (RSDs 3–7%).
Stability of ceftriaxone in water and cerebrospinal fluid determined by high‐performance liquid chromatography
Authors: de Diego Glaría Marta , Moscciati Gloria Godoy , Ramos Ricardo Godoy , Riquelme Marcelo Maturana
Published: July 2003

A study of the stability of ceftriaxone in water and cerebrospinal fluid in the presence or the absence of buffer at different storage temperatures was performed by liquid chromatography on a C18 column (125×4 mm, 5 μm) using a mobile phase consisting of acetonitrile (300 mL), 0.1 M phosphate buffer (pH 7.4; 50 mL), tetrabutylammonium bromide (3.2 g) made up to a volume of 1 L with water. Detection was at 270 nm with a 50 μL loop and 1 mL/min flow. The study was performed with an without 0.05 M phosphate buffer (pH 6.0) and at room temperature (25 ± 2°C), +8°C, –20°C, and –40°C, over 15 days, 78 days, and 111 days (–20°C and –40°C), respectively. At all the temperatures studied, the degradation of ceftriaxone followed first‐order kinetics. Degradation of the drug was greater at higher temperatures and in the absence of phosphate buffer. Lower storage temperatures and the presence of 0.05 M phosphate buffer (pH 6.0) therefore improved the stability of ceftriaxone in water and cerebrospinal fluid.
Development and validation of a high‐performance liquid chromatographic procedure for the determination of herbicide residues in surface and agriculture waters
Authors: Zanella Renato , Primel Ednei G. , Gonçalves Fábio F. , Kurz Márcia H. S. , Mistura Clóvia M.
Published: July 2003

A procedure has been developed for the determination of quinclorac, bentazone, 2,4‐D, clomazone, and propanil residues in surface and agriculture waters by SPE and HPLC‐UV. The method was validated and was applied for levels between 0.1 and 0.5 g/L, after a 500‐fold pre‐concentration. Average recoveries ranged from 85.7 to 109.8% with overall relative standard deviations of 1.8 to 13.4%.
Analysis of volatile composition of honey by solid phase microextraction and gas chromatography‐mass spectrometry
Authors: Soria Ana Cristina , Martínez‐Castro Isabel , Sanz Jesús
Published: July 2003

Honey aroma is largely dependent on its volatile fraction, which in turn is influenced by nectar composition and by possible modifications after harvesting. Solid phase microextraction (SPME) allows a simple and rapid fractionation of volatile compounds in honey as a prior step to their GC‐MS qualitative and quantitative determination. A simple SPME‐based procedure has been developed for GC‐MS analysis of honey volatiles and applied to the study of 6 different commercial honeys. The possibility of honey characterization from the analytical data obtained by the SPME method is discussed.
Enantioseparation of dansyl amino acids on terguride‐based chiral selectors. Part I: Capillary electrophoretic separation
Authors: Honzátko Aleš , Votruba Jaroslav , Olšovská Jana , Flieger Miroslav , Bachechi Fiorella , Ferrantelli Paola , Sinibaldi Massimo , Cvak Ladislav
Published: July 2003

A method of separation of dansyl amino acid (Dns‐AA) enantiomers by capillary electrophoresis (CE) using terguride‐based chiral selectors (CSs) was developed using linear polyacrylamide coated capillaries. Due to the high UV absorption of all studied CSs, only the capillary was filled with CS, while the inlet and outlet vials contained buffer solution only. Conditions were found for baseline separation of all Dns‐AA under study. L‐Dns‐AAs were eluted prior to D‐Dns‐AAs on all studied CSs. Use of the optical antipode of allyl‐terguride resulted in reversal of elution order of all Dns‐AAs (the D‐form was eluted prior to the L‐form). The best enantioselectivity was achieved for hydroxyl group‐containing AAs, i. e. serine and threonine. This finding is in good agreement with the proposed mechanism of chiral recognition of these AAs determined by X‐ray studies. Seven CSs with different N(1)‐side chain units, five of them designed for the preparation of silica based HPLC chiral stationary phases, were tested for their ability to resolve enantiomers of Dns‐AAs. Different polarity and hydrophobicity of N(1)‐side chains of the CSs resulted in different CS mobilities, thus influencing the effective separation time in the capillary. 1‐(5‐Aminopentyl)‐terguride showed the best enantioseparation and resolution for the Dns‐AAs studied.
Characterisation of a new minor urinary metabolite of piperine, an omnipresent food component, by LC‐MS/MS
Authors: Bajad Sunil , Khajuria Ravi K. , Suri Om P. , Bedi Kasturi L.
Published: July 2003

This study describes the detection and characterisation of a new minor metabolite of piperine in rat urine by LC‐MS/MS. The metabolite was partially purified using Sephadex®–LH20 column chromatography. Even in partially purified samples, the concentration was so low that NMR data could not be obtained using LC/NMR. However, comparative LC‐MS/MS as well as UV data of piperine (m/z 285) and the metabolite (m/z 287) gave very specific information to explain the difference of two mass units in the structures of these molecules. The proposed structure of the metabolite is E,E‐1‐[5‐(3‐methoxy‐4‐hydroxy‐phenyl)‐1‐oxo‐2,4‐pentadienyl]piperidine. Like human urinary metabolites, this metabolite retains the conjugated side chain and piperidine ring of the parent molecule while the methylenedioxy ring is cleaved. The study emphasises the role of LC‐MS/MS as a powerful tool in drug metabolism studies, particularly in identifying unstable or minor metabolites.
Experimental and modeling study of shock‐tube oxidation of acetylene
Authors: Eiteneer Boris , Frenklach Michael
Published: July 2003

Nine mixtures of acetylene and oxygen diluted in argon were studied behind reflected shock waves at temperatures of 1150–2132 K and pressures of 0.9–1.9 atm. Initial compositions were varied from very fuel‐lean to moderately fuel‐rich, covering equivalence ratios of 0.0625–1.66. Two more mixtures with added ethylene were used to boost the sensitivity to reactions of vinyl oxidation. The progress of reaction was monitored by laser absorption of CO molecules. The collected experimental data were subjected to extensive detailed chemical kinetics analysis. The initial kinetic model was assembled based on recent literature data and then optimized using the solution mapping technique. The analysis was extended to include recent experimental observations of Hidaka and co‐workers (Combust Flame 1996, 107, 401). The derived model reproduces closely both sets of experimental data, the result obtained by modifying nine rate coefficients and three enthalpies of formation of intermediate species. The identified parameter tradeoffs and justification for the changes are discussed. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 391–414, 2003
H‐atom abstraction from selected CH bonds in 2,3‐dimethylpentanal, 1,4‐cyclohexadiene, and 1,3,5‐cycloheptatriene
Authors: Tuazon Ernesto C. , Aschmann Sara M. , Nguyen Marie V. , Atkinson Roger
Published: July 2003

The gas‐phase reactions of OH radicals with 1,4‐cyclohexadiene, 1,3,5‐cycloheptatriene, and 2,3‐dimethylpentanal have been investigated to determine the importance of H‐atom abstraction at specific positions in these molecules. Benzene was observed as a product of the reaction of OH radicals with 1,4‐cyclohexadiene in 12.5 ± 1.2% yield, in good agreement with a previous study and indicating that this is the fraction of the reaction proceeding by H‐atom abstraction from the allylic CH bonds. In contrast, no formation of tropone from 1,3,5‐cycloheptatriene was observed, suggesting that in this case H‐atom abstraction is not important. For the reaction of OH radicals with 2,3‐dimethylpentanal, formation of 3‐methyl‐2‐pentanone was observed in 5.4 ± 1.0% yield (after correction for reaction of 3‐methyl‐2‐pentanone with OH radicals), and this product is predicted to be formed after initial H‐atom abstraction from the 2‐position CH group. Acetaldehyde and 2‐butanone were also observed as products, with initial yields of ∼90% and ∼26%, respectively, and their formation appeared to involve, at least in part, an intermediary acyl peroxy radical. Using a relative rate method, the measured rate constants for the reactions of OH radicals with 2,3‐dimethylpentanal, 3‐methyl‐2‐pentanone, and tropone are (in units of 10−12cm3molecule−1s−1) 2,3‐dimethylpentanal, 42 ± 7; 3‐methyl‐2‐pentanone, 6.87 ± 0.08; and tropone, 42 ± 6. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 415–426, 2003
Temperature and pressure dependence of the reaction of OH and CO: Master equation modeling on a high‐level potential energy surface
Authors: Senosiain Juan P. , Musgrave Charles B. , Golden David M.
Published: July 2003

The temperature and pressure dependence of the reaction of OH + CO has been modeled using the (energy‐resolved) master equation and RRKM theory. These calculations are based on the coupled‐cluster potential energy surface of Yu and co‐workers (Chem Phys Lett 349, 547–554, 2001). As is well known, this reaction shows a strong non‐Arrhenius behavior at moderate and low temperatures because of the stabilization of the HOCO intermediate. Kinetic simulations are in excellent agreement with experiments at temperatures above 300 K, but the agreement is only modest at temperatures below 250 K. Our calculations indicate that the contribution of tunneling to the rate constant is marginal, given the small energy difference between the transition states corresponding to formation and decomposition of the HOCO intermediate. Parametric fits to the calculated rate constants are provided for modeling purposes. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 464–474, 2003
Supramolecular Control of Ester Hydrolysis in Poly(ethylene glycol)‐Interlocked Hydrogels
Authors: Ichi Takahiro , Ooya Tooru , Yui Nobuhiko
Published: July 2003

Poly(ethylene glycol) (PEG)‐interlocked hydrogels were prepared by linking the PEG with α‐cyclodextrins (α‐CDs) threaded onto a PEG chain having ester linkages at the terminals (hydrolyzable polyrotaxane). These hydrogels were examined to clarify the effect of ionic strength of phosphate buffers, pH, and the addition of ethanol on erosion time in relation to inclusion states of α‐CDs with the ester linkages. The most characteristic phenomenon of the hydrogel erosion was observed in an ethanol/PBS cosolvent system: the time to reach the complete erosion time was shortened with decreasing water content. NMR analysis revealed that the ester linkages were exposed to the aqueous environment due to the aggregation of α‐CDs. These results suggest that the movement of α‐CDs in the polyrotaxanes from the terminal ester region to the another region gives the ester linkages a chance to interact with water.

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Conjugates of Antibody‐Targeted PEG Multiblock Polymers with Doxorubicin in Cancer Therapy
Authors: Pechar Michal , Ulbrich Karel , Jelínková Markéta , Říhová Blanka
Published: July 2003

The synthesis and physico‐chemical characterisation of biodegradable multiblock polymer drug carriers based on poly(ethylene glycol) (PEG) are described. The blocks of PEG (${{\bar{M}}_{\rm w}}$ = 2 000) are interconnected by an enzymatically degradable tripeptide derivative consisting of one Lys and two Glu residues. An anticancer drug, doxorubicin (Dox), was attached to the polymer carrier by a Gly‐Phe‐Leu‐Gly tetrapeptide spacer, which is also susceptible to degradation by lysosomal enzymes. A targeting polyclonal antibody was covalently linked to the polymer‐Dox conjugate by the aminolytic reaction of reactive sulfosuccinimidyl ester groups of the polymer with the protein. The resulting antibody‐polymer‐drug conjugates were characterised by SEC, UV/VIS spectrophotometry and amino acid analysis. Although the studied polymers show only a moderate antiproliferative activity against concanavalin A‐stimulated murine splenocytes and a murine T‐cell EL 4 lymphoma in vitro, they exhibited significant antitumour efficiency against murine T‐cell EL 4 lymphoma in vivo.

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Application of Electrospray Ionization Mass Spectrometry to the Elucidation of the Primary Structure of Lignin
Authors: Evtuguin Dmitry V. , Amado Francisco M. L.
Published: July 2003

Electrospray ionization mass spectrometry (ESI‐MS) was successfully applied to the structural analysis of lignin. The structure of oligomers fractionated from Eucalyptus globulus dioxane lignin was elucidated using tandem mass spectrometry, and the information on fragmentation patterns was provided by experiments on dimeric model compounds. Data obtained revealed a significant abundance in the lignin macromolecules of linear fragments that were composed of 8‐O‐4′‐linked syringyl/guaiacyl units and syringaresinol.

The proposed linear fragment of the E. globulus lignin molecule.

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The proposed linear fragment of the E. globulus lignin molecule.
Synthesis of Sequential Polypeptides Containing O‐Phospho‐L‐Serine
Authors: Yamamoto Hiroyuki , Saitoh Arihiro , Ohkawa Kousaku
Published: July 2003

The chemistry of phosphoserine [Ser(P)] containing peptides and polypeptides was extensively investigated to explore a new biomineralization material science. The selective cleavage of the O,O′‐diphenyl phospho‐protecting groups of Ser(PO3Ph2) was examined using hydrogenolysis catalysts. Among the catalysts examined, only PtO2 in 50% trifluoroacetic acid (TFA)/AcOH successfully cleaved the protecting group of Ser(PO3Ph2) to give Ser(P). Based on these characteristic new findings, Ser(P)‐containing dipeptides such as Gly‐Ser(P), Ala‐Ser(P), Ser‐Ser(P), Asp‐Ser(P), Glu‐Ser(P), and Lys‐Ser(P), and tetrapeptide [Asp‐Ser(P)]2 were synthesized by a facile method. When we used the Ser(PO3Ph2) residues at the C terminals, the amino functional groups of amino acids and peptides can be coupled by the unsymmetric mixed anhydride using isobutyl chloroformate but cannot be by the symmetric anhydride method using dicyclohexylcarbodiimide. Neither unsymmetric mixed anhydride nor symmetric anhydride can be coupled with p‐nitrophenol at their C terminals. High‐molecular‐weight sequential polypeptides containing Ser(P) such as poly[Ser(P)‐Xaa] (Xaa: Gly, Ala, Ser, Lys, Asp, Glu) and poly[Gly‐Ser(P)‐Gly] were first synthesized by the polycondensation of the di‐ and tripeptide p‐nitrophenyl active esters, followed by the quantitative elimination of the diphenyl protecting groups by PtO2 in TFA/AcOH. The new strategy to synthesize Ser(P)‐containing peptides and model proteins may help the development of hybrid formulations of marine and biomimetic protein minerals.

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Use of psychiatric drugs in Slovenia in comparison to Scandinavian countries
Authors: Fürst Jurij , Kocmur Margareta
Published: July 2003

Purpose

To find out the consumption of psychotropic drugs in Slovenia and the extent to which Slovenian consumption correlates to Scandinavian countries.

Methods

Data of ambulatory prescribing of psychiatric drugs in Slovenia for the years 1999 and 2000 and data for Norway, Sweden and Denmark are shown. All data are expressed in defined daily doses per thousand inhabitants per day (DDD's).

Results

The use of all neuroleptics in Slovenia is lower (5.3 vs 6.1–7.6 DDD's), however the share of atypicals (34%) is comparable to Scandinavian countries. Use of anticholinergics is up to five times greater (1.6 vs 0.3–0.5 DDD's). The use of lithium is five time lower (0.2 vs 1.1–1.4). Regarding the use of antidepressants, Slovenia is behind Scandinavia (12.2 vs 30–47 DDD's), whereas the share of SSRI's (73%) is at the same level. The use of anxiolytics is higher (25.4 vs 16–22.4 DDD's) and ratio with antidepressants is also unfavourable. The use of hypnotics and sedatives is favourably low (10.7 vs 31.8–44.6 DDD's).

Conclusions

Low use of hypnotics and sedatives is favourable. The share of new neuroleptics and antidepressants is comparable. The use of antidepressants is probably too low. However, prescribing guidelines for anxiolytics, anticholinergics (too high use of both group) and lithium (too low use) should be introduced in Slovenia. Copyright © 2003 John Wiley & Sons, Ltd.
Increased suicide attempt rate among patients interrupting use of atypical antipsychotics
Authors: Herings Ron M. C. , Erkens Joëlle A.
Published: July 2003

Purpose

The aim of the study is to investigate whether patients at risk to commit suicide could be identified based on their drug refill patterns.

Methods

Data for this study were obtained from the PHARMO system comprising drug‐dispensing data linked to hospital discharge records. All patients aged 15–45 years, suspected to suffer from schizophrenia and exclusive users of olanzapine or risperidone were selected. The use of antipsychotics was converted into treatment episodes of uninterrupted use. Therapy non‐compliance was defined as a drug holiday of at least 30 days. The follow‐up started with a treatment episode of at least 90 days. Relative risks for suicide attempts and 95% confidence limits due to drug holidays were estimated using Poisson regression analyses.

Results

Of 603 patients, 33% interrupted treatment for at least 30 days. An increased suicide attempt rate was observed when comparing uninterrupted and interrupted drug use (20.0/1000 person years vs 72.1/1000 person years, respectively). A four‐fold increased risk for attempting suicide among patients with drug holidays was found (RRadjusted for age and gender 4.2, 95%CI: 1.7–10.1) compared to patients without drug holidays.

Conclusions

Patients who do not refill atypical antipsychotics in time can be identified in the pharmacy and are most likely those with an increased risk to commit suicide. Copyright © 2003 John Wiley & Sons, Ltd.
The adjunctive use of a centralised database in the monitoring of clozapine‐related neutropenia
Authors: Pascoe Steven J.
Published: July 2003

Objective

To assess the effectiveness of centralised routine monitoring of blood counts in subjects receiving clozapine.

Design

A cohort study based on a prospective drug exposure database.

Setting and Participants

Patients with schizophrenia in 38 specialised centres across Australia.

Outcome Measures

The time from detection of neutropenia to the interruption of therapy, the time to recovery of the absolute neutrophil count, the eventual outcome of subjects developing neutropenia.

Results

A total of 1500 subjects were registered on the database. Seven subjects developed severe neutropenia (a neutrophil count < 1.5 × 109/L) whilst on therapy. Mean time to cessation of therapy was 1.6 days (range < 1–6 days). Neutrophil counts recovered to normal levels in all subjects after 6.4 days (range< 1–13).

Conclusions

In the population investigated, the addition of a centralised database to clinical monitoring resulted in very rapid detection of severe neutropenia and an equally rapid cessation of therapy. In the sample investigated, this led to very low morbidity and zero mortality. Copyright © 2003 John Wiley & Sons, Ltd.
Factors influencing prescription of CNS medications in different elderly populations
Authors: Craig David , Passmore A. Peter , Fullerton Ken J. , Beringer Timothy R.O. , Gilmore David H. , Crawford Vivienne L.S. , McCaffrey Patricia M. , Montgomery Anne
Published: July 2003

Factors influencing the use of neuroleptic and other CNS‐acting medications (‘antidepressants’ and ‘hypnotics/anxiolytics’) were examined in different elderly populations (>65 years): long‐stay care hospital subjects (n = 381), nursing home subjects (n = 1247), private residential home subjects (n = 321), statutory residential home subjects (n = 525), old age psychiatry facility subjects (n = 48), community dwellers (n = 97), in different geographical areas (urban n = 1223 and rural n = 1396). Neuroleptics were prescribed in 28% of the individuals, hypnotics/anxiolytics in 33% and antidepressants in 12%. Prescription of neuroleptics was significantly predicted by institutional placement (other than long‐stay care hospital facility), lower cognitive function and rural geographical area. Age greater than 75 years and lower functional score (lower dependency) significantly decreased the likelihood of receipt of neuroleptics. Antidepressant use was significantly less likely in male subjects, patients with cognitive impairment and patients greater than 85 years. Institutional placement (other than long‐stay care hospital facility and old age psychiatry facility) and rural locality predicted increased likelihood of antidepressant prescription. Institutional placement (other than long‐stay care hospital facility) and geographical (rural) location were significant independent predictors of hypnotic/anxiolytic use. Prescription of hypnotic/anxiolytic drug class was significantly less likely in those individuals with lower cognitive status. In this representative elderly cohort, patient characteristics: age, sex, cognitive score, functional score, place of residence and geographical location markedly influenced drug utilisation. Copyright © 2003 John Wiley & Sons, Ltd.
Assessment of diagnostic markers by goodness‐of‐fit tests
Authors: Nakas Christos , Yiannoutsos Constantin T. , Bosch Ronald J. , Moyssiadis Chronis
Published: July 2003

Receiver operating characteristic (ROC) curves are useful statistical tools used to assess the precision of diagnostic markers or to compare new diagnostic markers with old ones. The most common index employed for these purposes is the area under the ROC curve (θ) and several statistical tests exist that test the null hypotheses H0: θ= 0.5 or H0: θ1=θ2, in the case of two‐marker comparisons, against alternatives of interest. In this paper we show that goodness‐of‐fit of uniformity of the distribution of the false positive (true positive) rates can be used instead of tests based on the area index. A semi‐parametric approach is based on a completely specified distribution of marker measurements for either the healthy (F) or diseased (G) subjects, and this is extended to the two‐marker case. We then extend to the one‐ and two‐marker case when neither distribution is specified (the non‐parametric case). In general, ROC‐based tests are more powerful than goodness‐of‐fit tests for location differences between the distributions of healthy and diseased subjects. However ROC‐based tests are less powerful when location‐scale differences exist (producing ROC curves that cross the diagonal) and are incapable of discriminating between healthy and diseased samples when θ=0.5 but F ≠ G. In these cases, goodness‐of‐fit tests have a distinct advantage over ROC‐based tests. In conclusion, ROC methodology should be used with recognition of its potential limitations and should be replaced by goodness‐of‐fit tests when appropriate. The latter are a viable alternative and can be used as a ‘black box’ or as an exploratory first step in the evaluation of novel diagnostic markers. Copyright © 2003 John Wiley & Sons, Ltd.
Implementation and applications of bootstrap methods for the National Immunization Survey
Authors: Smith Philip J. , Hoaglin David C. , Battaglia Michael P. , Barker Lawrence
Published: July 2003

In complex probability sample surveys, numerous adjustments are customarily made to the survey weights to reduce potential bias in survey estimates. These adjustments include sampling design (SD) weight adjustments, which account for features of the sampling plan, and non‐sampling design (NSD) weight adjustments, which account for non‐sampling errors and other effects. Variance estimates prepared from complex survey data customarily account for SD weight adjustments, but rarely account for all NSD weight adjustments. As a result, variance estimates may be biased and standard confidence intervals may not achieve their nominal coverage levels. We describe the implementation of the bootstrap method to account for the SD and NSD weight adjustments for complex survey data. Using data from the National Immunization Survey (NIS), we illustrate the use of the bootstrap (i) for evaluating the use of standard confidence intervals that use Taylor series approximations to variance estimators that do not account for NSD weight adjustments, (ii) for obtaining confidence intervals for ranks estimated from weighted survey data, and (iii) for evaluating the predictive power of logistic regressions using receiver operating characteristic curve analyses that account for the SD and NSD adjustments made to the survey weights. Copyright © 2003 John Wiley & Sons, Ltd.
Gatekeeping strategies for clinical trials that do not require all primary effects to be significant
Authors: Dmitrienko Alexei , Offen Walter W. , Westfall Peter H.
Published: July 2003

In this paper we describe methods for addressing multiplicity issues arising in the analysis of clinical trials with multiple endpoints and/or multiple dose levels. Efficient ‘gatekeeping strategies’ for multiplicity problems of this kind are developed. One family of hypotheses (comprising the primary objectives) is treated as a ‘gatekeeper’, and the other family or families (comprising secondary and tertiary objectives) are tested only if one or more gatekeeper hypotheses have been rejected. We discuss methods for constructing gatekeeping testing procedures using weighted Bonferroni tests, weighted Simes tests, and weighted resampling‐based tests, all within the closed testing framework. The new strategies are illustrated using an example from a clinical trial with co‐primary endpoints, and using an example from a dose‐finding study with multiple endpoints. Power comparisons with competing methods show the gatekeeping methods are more powerful when the primary objective of the trial must be met. Copyright © 2003 John Wiley & Sons, Ltd.
Interval estimation of the attributable risk for multiple exposure levels in case‐control studies with confounders
Authors: Lui Kung‐Jong
Published: July 2003

The attributable risk (AR) is one of the most important and commonly‐used epidemiological indices to assess the public health importance of an association between a risk factor and a disease. When the underlying risk factor has multiple exposure levels in the presence of confounders, we consider the case‐control studies using random sampling to collect the cases and controls here. We develop four asymptotic interval estimators for AR, including the interval estimator using Wald's statistic, the interval estimator using the logarithmic transformation, the interval estimator using the logit transformation, and the interval estimator derived from a quadratic equation. We apply Monte Carlo simulation to evaluate the finite‐sample performance of these interval estimators in a variety of situations. We demonstrate that given an adequately large sample size, all the estimators developed here can actually perform reasonably well. We note that the interval estimator using the logit transformation may be of limited use when the number of studied subjects is not large. We also note that the interval estimator using the logarithmic transformation can lose efficiency compared to the interval estimator using Wald's statistic or the interval estimator derived from a quadratic equation developed in this paper. Finally, we use the data taken from a case‐ontrol tudy of the oral contraceptive use in myocardial nfarction patients with various smoking levels to illustrate he practical usefulness of these estimators. Copyright © 2003 John Wiley & Sons, Ltd.
Macrophage inflammatory protein‐related protein‐2, a novel CC chemokine, can regulate preadipocyte migration and adipocyte differentiation
Authors: Kim Chu-Sook , Kawada Teruo , Yoo Hoon , Kwon Byung-Se , Yu Rina
Published: July 2003

Adipocytes not only store energy, but also secrete biologically active molecules called adipocytokines, which play a pivotal role in adipocyte‐related pathological processes such as diabetes and cardiovascular disease. Recent studies have shown that preadipocyte/adipocyte expresses chemokines (e.g. monocyte chemoattractant protein‐1, macrophage inflammatory protein‐1 alpha) which alter adipocyte function, indicating the involvement of chemokines in adipocyte‐related pathologies. The current study investigated the potential of macrophage inflammatory protein‐related protein‐2 (MRP‐2), a novel CC chemokine, to modulate preadipocyte trafficking and adipocyte differentiation. MRP‐2 and its receptors were highly expressed in preadipocytes and differentiated adipocytes as well as in the mouse fat pad. Chemotaxis assays revealed that MRP‐2 was a specific chemotactic regulator in preadipocyte migration. The levels of MRP‐2 expression in adipose tissue were enhanced in obese mice compared to lean mice. MRP‐2 secretion by preadipocytes was suppressed during differentiation. MRP‐2 suppressed the expression of adipocyte differentiation markers such as adipocyte fatty acid‐binding protein and glycerol‐3 phosphate dehydrogenase. Taken together, our data suggest that MRP‐2 plays a role in the regulation of preadipocyte migration and adipocyte differentiation during adipose tissue development. MRP‐2 may be another adipocytokine, which can be involved in the adipocyte‐related pathological process.
Potassium uptake in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 mainly depends on a Ktr‐like system encoded by slr1509 (ntpJ)
Authors: Berry Stephan , Esper Berndt , Karandashova Inga , Teuber Markus , Elanskaya Irina , Rögner Matthias , Hagemann Martin
Published: July 2003

The molecular basis of potassium uptake in cyanobacteria has not been elucidated. However, genes known from other bacteria to encode potassium transporters can be identified in the genome of Synechocystis sp. strain PCC 6803. Mutants defective in kdpA and ntpJ were generated and characterized to address the role of the Kdp and KtrAB systems in this strain. KtrAB is crucial for K+ uptake, as the ΔntpJ mutant shows slowed growth, slowed potassium uptake kinetics, and increased salt sensitivity. The ΔkdpA mutant has the same phenotype as the wild type even at limiting potassium, but a ΔkdpAΔntpJ double mutant is not viable, indicating a role of Kdp for potassium uptake when the Ktr system is not functioning.
Pneumocystis carinii BCK1 functions in a mitogen‐activated protein kinase cascade regulating fungal cell‐wall assembly
Authors: Thomas Charles F. , Vohra Pawan K. , Park John G. , Puri Veenu , Limper Andrew H. , Kottom Theodore J.
Published: July 2003

Pneumocystis pneumonia remains the most common AIDS‐defining opportunistic infection in people with HIV. The process by which Pneumocystis carinii constructs its cell wall is not well known, although recent studies reveal that molecules such as β‐1‐3‐glucan synthetase (GSC1) and environmental pH‐responsive genes such as PHR1 are important for cell‐wall integrity. In closely related fungi, a specific mitogen‐activated protein kinase (MAPK) cascade regulates cell‐wall assembly in response to elevated temperature. The upstream mitogen‐activated protein kinase kinase kinase (MAPKKK, or MEKK), BCK1, is an essential component in this pathway for maintaining cell‐wall integrity and preventing fungal cell lysis. We have identified a P. carinii MEKK gene and have expressed it in Saccharomyces cerevisiae to gain insights into its function. The P. carinii MEKK, PCBCK1, corrects the temperature‐sensitive cell lysis defect of bck1Δ yeast. Further, at elevated temperature PCBCK1 restored the signaling defect in bck1Δ yeast to maintain expression of the temperature‐inducible β‐1‐3‐glucan synthetase gene, FKS2. PCBCK1, as a functional kinase, is capable of autophosphorylation and substrate phosphorylation. Since glucan machinery is not present in mammals, a better understanding of this pathway in P. carinii might aid in the development of novel medications which interfere with the integrity of the Pneumocystis cell wall.
Differential binding of Sin3 interacting repressor domains to the PAH2 domain of Sin3A
Authors: Pang Yuan-Ping , Kumar Ganesh A , Zhang Jin-San , Urrutia Raul
Published: July 2003

The Sin3 interacting domain (SID), originally described in the Mad family of repressors, is a novel transcriptional repressor domain that binds the PAH2 domain of corepressors Sin3A and Sin3B with high affinities. The conserved SID‐like domains are reportedly present in five KLF proteins. However, the KLF SIDs and the Mad SIDs can be classified into two subtypes according to sequence similarity. Here, we report the finding from computational and experimental studies that the two subtypes of SID domains bind differentially to Sin3A. This finding offers insights into a mechanism of cell growth regulation by interactions of different subtypes of SID‐containing repressor proteins with Sin3. It also provides the structural basis for developing selective modulators of Sin3.
Oxytocin in prefilled Uniject™ injection devices for managing third‐stage labor in Indonesia
Authors: Tsu V.D. , Sutanto A. , Vaidya K. , Coffey P. , Widjaya A.
Published: July 2003

We assessed the use and acceptability of an injection device (Uniject™) prefilled with oxytocin, as part of active management of third‐stage labor (AMTL) by Indonesian midwives attending home births. We interviewed 140 village midwives (bidan di desa) and 2220 mothers whose deliveries they attended during the intervention period. We completed baseline and post‐intervention assessments to determine their experiences and views of oxytocin Uniject™ use. Delivery logs and supervisory reports were reviewed. The assessment was done in three rural districts and one municipality in Lombok. Injection practices and oxytocin availability did not change dramatically, although dose accuracy, use of sterile injection equipment, and proper disposal improved when the Uniject™ device was used. Midwives had little difficulty using the Uniject™ device properly; they overwhelmingly preferred it to standard needles and syringes. Postpartum hemorrhage rates did not change substantially. Oxytocin via Uniject™ holds promise for safer, more convenient use of oxytocin by trained midwives attending home deliveries, thereby potentially reducing the incidence of postpartum hemorrhage.