bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of the frequency of the 22q11 deletion in Afrikaner schizophrenic patients
Authors: Wiehahn G.J. , Bosch G.P. , du Preez R.R. , Pretorius H.W. , Karayiorgou M. , Roos J.L. 
Published: June 2004

AbstractA hemizygous deletion of the q11 band on chromosome 22 occurs in 1 of every 5,950 live births (0.017%). The deletion is mediated by low copy repeats (LCRs) flanking this locus. Presence of the deletion is associated with variable phenotypic expression, which can include distinctive facial dysmorphologies, congenital heart disease and learning disabilities. An unusually high percentage of individuals with this deletion (25–30%) have been described to develop schizophrenia or schizoaffective disorder. In previous studies, the prevalence of the 22q11 deletion in patients with schizophrenia was found to be approximately 2% in Caucasian adults and 6% in childhood‐onset cases. Both these frequencies represent a dramatic increase from the prevalence of the deletion in the general population. In this study, we investigate the occurrence of the 22q11 deletion in an independent sample of schizophrenic patients of Afrikaner origin. We first ascertained a sample of 85 patients who meet full diagnostic criteria for schizophrenia for presence of two or more of the clinical features associated with presence of the 22q11 deletion. A group of six patients (7%) met these criteria. This group was subjected to fluorescent in situ hybridization (FISH) and presence of the 22q11 deletion was confirmed for two subjects. Our study therefore confirms the previously reported rate of 2% frequency of the 22q11 deletion in adult schizophrenic patients and provides a two‐stage screening protocol to identify these patients. © 2004 Wiley‐Liss, Inc.
Synthesis and structure of polysiloxane liquid crystalline elastomers with a mesogenic crosslinking agent
Authors: Jia Ying‐Gang , Zhang Bao‐Yan , Tian Mei , Pan Wei 
Published: June 2004

AbstractA new mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of a nonmesogenic crosslinking agent for liquid crystalline elastomers. The synthesis of new side‐chain liquid crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 is described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and elastomers were confirmed by 1H NMR and FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior is discussed. The elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and nematic‐threaded texture. However, when the crosslinking density reached 21.6 mol %, the mesophase of polymer P‐8 disappears. The adoption of a mesogenic crosslinking agent diminishes the perturbation of a nonmesogenic crosslinking agent on mesophase of liquid crystalline elastomers, and isotropic temperature and a mesomorphic temperature range slightly decreased with increasing content of the crosslinking agent. In addition, X‐ray analysis shows nematic polydomain network polymers can transform into smectic monodomain by stress induction, leading to the orientation formation macroscopically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1736–1742, 2004
Crosslinking of natural and polybutadiene rubbers with thiuram sulfur donors in the presence of a thiuram monosulfide
Authors: Valentín J. L. , Rodríguez A. , Marcos‐Fernández A. , González L. 
Published: June 2004

AbstractThe influence of tetramethylthiuram monosulfide (TMTM) in the vulcanization process of natural rubber and butadiene rubber with dipentamethylene thiuram tetrasulfide (DPTT) was investigated. Vulcanization parameters as reaction rate and reversion varied when TMTM was added in NR‐DPTT formulations. Crosslinking density and proportion of monosulfidic crosslinks increased with TMTM content increase. However, a drop in physical properties was observed at high TMTM content and at long times of curing well over t97. Formation of densely crosslinked areas due to polymerization reaction was postulated as the origin of these variations. In BR‐DPTT compounds, torque and monosulfidic crosslink proportions increased when TMTM was added. Polymerization reaction takes place in BR systems too. However, in BR vulcanizates, C—C bonds decreased with TMTM proportion, whereas in NR vulcanizates increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1756–1761, 2004
Tensile properties, morphology, and thermal behavior of PVC composites containing pine flour and bamboo flour
Authors: Ge X. C. , Li X. H. , Meng Y. Z. 
Published: June 2004

AbstractComposites of unplasticized poly(vinyl chloride) (PVC) blended with bamboo flour and pine flour, respectively, were prepared in a batch mixer followed by compression molding. The effects of wood flour fillers on the morphology, static mechanical properties, and thermal properties of the composites were investigated. Compared with neat PVC resin, the introduction of both bamboo flour and pine flour significantly improved the stiffness of the composites, while decreasing the tensile strength to some extent. Tensile tests showed that pine flour–filled composites exhibited better mechanical properties than those filled with bamboo flour with the same particle size at the same loading level. Scanning electron microscopic examination revealed good dispersion and alignment tendency of short pine fiber within the composites at a lower loading level. Moreover, experimental results indicated that both bamboo flour and pine flour additions showed no obviously adverse effect on the thermal stabilities of these composites. Based on the comprehensive properties, these composites meet the need of woodlike material for use as wood structures. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1804–1811, 2004
Influence of alkali treatment on the structure of newcell fibers
Authors: Zhu Yawei , Ren Xuehong , Wu Chengyu 
Published: June 2004

AbstractAlkali treatment can change the structures and properties of cellulosic fibers. The aim of this work was to study the mechanism of structural changes of Newcell fibers treated with different alkali concentrations and two treatment methods. Raman spectra showed that the molecular conformation of Newcell fibers remained unchanged. X‐ray diffraction indicated that the crystal structure of Newcell cellulose II, treated with different alkali concentrations and different methods, did not change. With the increase of alkali concentration the crystallinty and crystallinity orientation index of Newcell fibers in their original length decreased slightly, whereas those of fibers in relaxed condition substantially decreased, and the crystallite size of 101¯ and 002 increased in both methods. The quasi‐crystallite disassociation and recrystallization in the quasi‐crystalline phase, during the process of alkali treatment, led to changes of crystallinity and orientation index of Newcell fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1731–1735, 2004
Lead Identification for Modulators of Multidrug Resistance based on in silico Screening with a Pharmacophoric Feature Model
Authors: Langer Thierry , Eder Monika , Hoffmann Remy D. , Chiba Peter , Ecker Gerhard F. 
Published: June 2004

AbstractConsiderable effort has been devoted to the characterization of P‐glycoprotein — drug interaction in the past. Systematic quantitative structure‐activity relationship (QSAR) studies identified both predictive physicochemical parameters and pharmacophoric substructures within homologous series of compounds. Comparative molecular field analysis (CoMFA) led to distinct 3D‐QSAR models for propafenone and phenothiazine analogs. Recently, several pharmacophore models have been generated for diverse sets of ligands. Starting from a training set of 15 propafenone‐type MDR‐modulators, we established a chemical function‐based pharmacophore model. The pharmacophoric features identified by this model were (i) one hydrogen bond acceptor, (ii) one hydrophobic area, (iii) two aromatic hydrophobic areas, and (iv) one positive ionizable group. In silico screening of the Derwent World Drug Index using the model led to identification of 28 compounds. Substances retrieved by database screening are diverse in structure and include dihydropyridines, chloroquine analogs, phenothiazines, and terfenadine. On the basis of its general applicability, the presented 3DQSAR model allows in silico screening of virtual compound libraries to identify new potential lead compounds.
New Antithrombotics with an Indazole Structure
Authors: Yildiz Ali Kemal , Rehse Klaus , Stasch Johannes‐Peter , Bischoff Erwin 
Published: June 2004

AbstractFifteen new indazole derivatives have been synthesized. In the Born test, compounds 4f and 4g were most active. They inhibited the blood platelet aggregation induced by collagen with an IC50 = 85 or 90 μM, respectively. After oral administration to rats (60 mg/kg) three of the compounds significantly inhibited the formation of thrombi in arterioles and venules. The strongest effect was observed with 4j which showed an inhibition of 15% in arterioles and 7% in venules. Further experiments showed that compound 4j does not mediate these effects by activating soluble guanylate cyclase, but likely by inhibiting phosphodiesterase isoform PDE 5.
Phenylpiperazinylmethylheterocycle Derivatives: Synthesis and Dopamine Receptor Binding Profiles
Authors: Abadi Ashraf H. 
Published: June 2004

AbstractFour series of phenylpiperazinylmethylimidazo[1, 2‐a]pyridine, phenylpiperazinylmethylpyrrole, phenylpiperazinylmethylbenzofuran, and phenylpiperazinylmethylbenzothiophene derivatives were synthesized and investigated for their in vitro binding profiles for the dopamine receptor subtypes D1, D2long, D2short, D3 and D4. All tested compounds showed selectivity towards the D4 receptor subtype. Affinity and selectivity for D4 follows the order imidazo[1, 2‐a]pyridine > benzofuran > benzothiophene > pyrrole derivatives. The D4‐related affinity and selectivity pattern seems to be dependent on the presence of a region of negative molecular electrostatic potential below the heterocyclic moiety.
Electrostatic Surface Potential Calculation on Several New Halogenated Benzimidazole‐like Dopaminergic Ligands
Authors: Šukalović V. , Andrić Deana , Roglić G. , Kostić‐Rajacčić Sladjana , Šoškić V. 
Published: June 2004

AbstractWe examined the effects of the electron density distribution (electrostatic surface potential; ESP) of several new benzimidazole‐type ligands on their binding affinity for the D1 and D2 dopamine receptors (DAR). Receptors were prepared from synaptosomal membranes of bovine caudate nuclei. [3H]SCH 23390 and [3H]spiperone were used as specific radiolabels for the D1 and D2 receptors, respectively. The ESP of these compounds was calculated using Gaussian 98 W software. Calculations performed with known dopaminergic ligands showed that the electron density charge in the aromatic ring of these compounds favors a higher binding affinity for the D2 DAR. This was confirmed by the synthesis of halogenated analogues of several known dopaminergic ligands. Halogenation resulted in an increase in the positive charge of the aromatic part of the molecule. None of the newly synthesized compounds was efficient in displacing [3H]SCH 23390 from the D1 DAR. The introduction of chlorine into the molecule led to a higher binding affinity for the D2 DAR of the new ligands in comparison to both parent compounds and brominated ligands. This difference probably originates from the difference in the sizes of chlorine and bromine atoms, which could influence the interaction of a ligand with the receptor binding site. However, among the new ligands with bromine as a substituent, two compounds (8b and 10b) expressed a higher binding affinity and two of them (9b and 11b) a lower binding affinity for the D2 DAR, when compared to unsubstituted parent compounds. These results indicate that the electrostatic surface potential of a ligand is an important factor in its interaction with the D2 DAR and that this should be taken into account during design and synthesis of dopaminergic compounds.
[1, 2‐Bis(2, 6‐difluoro‐3‐hydroxyphenyl)ethylene‐diamine]platinum(II) Complexes, Compounds for the Endocrine Therapy of Breast Cancer ‐ Mode of Action II: Contribution of Drug Inactivation, Cellular Drug Uptake and Sterical Factors in the Drug‐Target Interaction to the Antitumor Activity
Authors: Schertl Sabine , Hartmann Rolf W. , Batzl‐Hartmann Christine , Bernhardt Günther , Spruß Thilo , Beckenlehner Karin , Koch Marion , Krauser Rudolf , Schlemmer Richard , Gust Ronald , Schönenberger Helmut 
Published: June 2004

AbstractThe marked activity of [meso‐1, 2‐bis(2, 6‐difluoro‐3‐hydroxyphenyl)ethylenediamine]platinum(II) (meso‐3‐PtLL′, L, L′ = Cl2 or L = OH2, L′ = OSO3) on the hormone‐sensitive MXT‐M‐3, 2 breast cancer implanted in mice is most probably due to a mechanism based on the reduction of the endogenous estrogen level. Cytotoxic effects which are poorly pronounced in experiments on several breast cancer cell lines (e.g. MCF‐7), do not significantly contribute to the anti‐breast cancer activity of this compound. In contrast to this, the standard cisplatin and the structurally related comparison compound [meso‐1, 2‐bis(4‐fluorophenyl)ethylenediamine]platinum(II) (meso‐4‐PtLL′, L, L′ = Cl2 or L = OH2, L′ = OSO3) are strongly active in vivo as well as in vitro. Both effects entail programmed cell death, which is responsible for the inhibition of the tumor growth. The minor cytotoxicity of meso‐3‐PtLL′ in breast cancer cell cultures is caused neither by an inappropriate rate of reaction with bionucleophiles (e.g. by a too fast inactivation by plasma proteins) nor solely by the observed poor absorption by the tumor cells resulting in an insufficient drug concentration at the DNA. Additionally, an impeded reaction with biologically important, guanine‐rich sequences of DNA (owing to the 2, 6‐standing F atoms which hinder the drug‐target inter action) must be assumed as cause of its marginal cytotoxicity.
Increased apoptotic neutrophils and macrophages and impaired macrophage phagocytic clearance of apoptotic neutrophils in systemic lupus erythematosus
Authors: Ren Yi , Tang Jinling , Mok M. Y. , Chan Albert W. K. , Wu Adrian , Lau C. S. 
Published: June 2004

AbstractObjectiveTo evaluate whether patients with systemic lupus erythematosus (SLE) have a higher rate of apoptosis in and secondary necrosis of polymorphonuclear neutrophils (PMNs) and macrophages compared with controls; to compare the rate of macrophage phagocytic clearance of apoptotic PMNs in patients with SLE and healthy controls; to evaluate whether in vitro PMN and macrophage apoptosis and secondary necrosis, and the ability of macrophages to phagocytose apoptotic bodies, are correlated with lupus disease activity; and to determine whether macrophage clearance of apoptotic bodies in patients with SLE and normal controls is related to certain serum factors.MethodsThirty‐six patients with SLE and 18 healthy, nonsmoking volunteers were studied. PMNs and monocytes were isolated from fresh blood and cultured in the presence of different sources of serum. Apoptotic PMNs and macrophages were examined by annexin V binding and morphology on May–Giemsa–stained cytopreparations, at different time points. The presence of secondary necrotic PMNs and macrophages was verified by staining with trypan blue. Macrophage phagocytosis of apoptotic PMNs was measured using a coded, observer‐blinded, microscopically quantified phagocytosis assay. Cells were cultured in the presence of serum obtained from healthy subjects or from patients with SLE.ResultsAt 5 and 24 hours, the percentage of apoptotic PMNs from patients with SLE was significantly higher than that of PMNs from healthy subjects. At 24 and 48 hours, the percentage of secondary necrotic PMNs from patients with SLE was also significantly higher than the percentage of necrotic PMNs from controls. Serum from patients with SLE accelerated the rate of apoptosis in and secondary necrosis of PMNs from healthy subjects. Macrophages from SLE patients were less capable of phagocytosing apoptotic PMNs compared with macrophages obtained from controls. Macrophages from patients with active SLE were less capable of phagocytosing apoptotic PMNs than were macrophages from patients with inactive SLE, but the difference was not statistically significant. The percentage of phagocytosis of apoptotic PMNs by macrophages from SLE patients correlated negatively with the SLE Disease Activity Index, serum levels of anti–double‐stranded DNA, and the erythrocyte sedimentation rate, and correlated positively with serum levels of C3, C4, and albumin, the hemoglobin level, and the leukocyte count. Serum from SLE patients not only significantly increased macrophage apoptosis in cells from healthy subjects but also remarkably down‐regulated the clearance of apoptotic PMNs by macrophages from healthy subjects. In contrast, serum from healthy subjects significantly increased phagocytosis of apoptotic PMNs by macrophages from SLE patients.Conclusion
Reduction of atherosclerosis in low‐density lipoprotein receptor–deficient mice by passive administration of antiphospholipid antibody
Authors: Nicolo Danielle , Goldman Bruce I. , Monestier Marc 
Published: June 2004

AbstractObjectivePatients with antiphospholipid syndrome (APS) are at a high risk of developing atherosclerotic complications. Conversely, individuals with primary atherosclerosis have an increased prevalence of antiphospholipid antibodies (aPL) and antibodies to oxidized low‐density lipoproteins (ox‐LDL). Several studies suggest that these two antibody populations may in fact overlap, although it is unclear how aPL contribute to pathogenesis. In this study, we characterized an IgG monoclonal aPL and assessed its ability to modulate atherosclerosis in low‐density lipoprotein receptor–deficient (LDLR−/−) mice.MethodsThe cardiolipin‐reactive monoclonal antibody FB1 was obtained from an (NZW × BXSB)F1 mouse, a strain with APS features that make it prone to fatal myocardial infarctions. Using an enzyme‐linked immunosorbent assay, we investigated the binding of this antibody to phospholipid and LDL antigens. We also passively administered FB1 to atherosclerosis‐prone mice to determine its effect on atherogenesis.ResultsIn contrast to earlier studies of aPL that were specific for oxidized forms of LDL, FB1 cross‐reacted with both native LDL and ox‐LDL. In vivo, passive administration of FB1 significantly reduced plaque formation in atherosclerosis‐prone LDLR−/− mice.ConclusionThese results indicate that some aPL may play a protective role in atherogenesis and suggest a novel approach to the prevention of atherosclerosis.
Tacrolimus in rheumatoid arthritis patients receiving concomitant methotrexate
Authors: Kremer Joel M. , Habros Joseph S. , Kolba Karen S. , Kaine Jeffrey L. , Borton Mary Ann , Mengle‐Gaw Laurel J. , Schwartz Benjamin D. , Wisemandle Wayne , Mekki, for the Tacrolimus‐Methotrexate Rheumatoid Arthritis Qais A. 
Published: June 2004

AbstractObjectiveTo assess the safety of tacrolimus used in combination with oral methotrexate (MTX) to control the signs and symptoms of rheumatoid arthritis (RA) in patients whose disease remains active despite treatment with MTX.MethodsThis was a multicenter open‐label study conducted at 13 US sites. Eighty patients who at baseline had active RA (mean tender/painful joint count 29.4, mean swollen joint count 17.4, mean erythrocyte sedimentation rate 25.1 mm/hour) despite treatment for ≥1 month with a stable, maximally tolerated dosage of oral MTX (≤20 mg/week, median dosage 15 mg/week, range 5–20 mg/week) were enrolled and received 3 mg/day tacrolimus as a single oral dose once per day for 6 months while continuing to receive MTX at the existing stable dosage. All other disease‐modifying antirheumatic drugs were discontinued; stable dosage of nonsteroidal antiinflammatory drugs and oral corticosteroids (≤10 mg/day prednisone or its equivalent) were allowed. All 80 patients received at least one dose of the study drug and were included in the primary safety and efficacy analyses. Seventy‐five patients had at least one postbaseline efficacy assessment, and 63 patients (78.8%) completed the study. The primary clinical response criterion was the American College of Rheumatology definition of 20% improvement (ACR20) at the end of treatment.ResultsSeven patients (12.5%) withdrew from the study because of adverse events possibly or probably related to treatment with tacrolimus, and 4 (5.0%) withdrew due to lack of efficacy. One serious adverse event (pancreatitis) was possibly related to tacrolimus treatment. The mean (±SD) creatinine (Cr) level increased from 0.74 ± 0.16 mg/dl at baseline to 0.81 ± 0.22 mg/dl (P < 0.001) at the end of treatment. Twenty‐three patients (28.8%) had a ≥30% maximum increase in the Cr level from baseline during the study, with the Cr level in 3 patients (3.8%) exceeding the range considered normal for their age and sex. The maximum Cr level during the study was 1.8 mg/dl. The ACR20 clinical response rate at the end of treatment was 52.5% (95% confidence interval 41.6–63.4%).ConclusionIn patients whose active RA persists despite treatment with MTX, tacrolimus in combination with MTX is safe and well‐tolerated and provides clinical benefit.
Feasibility of T and Z scores from magnetic resonance imaging data for quantification of cartilage loss in osteoarthritis
Authors: Burgkart R. , Glaser C. , Hinterwimmer S. , Hudelmaier M. , Englmeier K.‐H. , Reiser M. , Eckstein F. 
Published: June 2004

AbstractObjectiveT scores (an indicator of the difference between patients and young healthy subjects) and Z scores (an indicator of the difference between patients and age‐matched healthy subjects) are used in the diagnosis of osteoporosis and form the current basis for the definition of osteoporosis by the World Health Organization. We tested the feasibility of using T and Z scores derived from quantitative cartilage imaging with magnetic resonance imaging (MRI) for the diagnosis of osteoarthritis (OA).MethodsHigh‐resolution MR images of tibial cartilage were acquired from 126 young healthy adults (ages 20–35 years), 24 age‐matched elderly healthy adults (ages 50–75 years), 7 OA patients prior to tibial osteotomy, and 7 OA patients prior to knee arthroplasty. Cartilage volume, thickness, surface area, and original joint surface area (before onset of disease) were determined in the medial and lateral tibia.ResultsThe cartilage volume of the medial tibia of osteotomy patients with varus malalignment displayed moderate T scores (−1.0), and more negative T scores (−3.8) were observed in knee arthroplasty patients with varus malalignment. Normalization of the cartilage volume to the original joint surface area substantially enhanced the scores in patients undergoing osteotomy (−2.3) and in patients undergoing knee arthroplasty (−5.5), and this was superior to the normalization ratios of cartilage volume to body height and cartilage volume to body weight, in terms of distinguishing the loss of articular cartilage.ConclusionQuantitative analysis of OA by MRI is feasible using T and Z scores. However, cartilage volume should be normalized to the individual joint surface area in order to maximize the discriminatory power of this technique for the diagnosis of OA.