bluuebunny/crossref_metadata_2025_split huggingface dataset:
RNA processing defects of the helicase gene RECQL4 in a compound heterozygous Rothmund–Thomson patient
Authors: Beghini Alessandro , Castorina Pierangela , Roversi Gaia , Modiano Philippe , Larizza Lidia 
Published: June 2003

AbstractRothmund–Thomson syndrome (RTS) (OMIM 268400) is an autosomal recessive genodermatosis associated with genomic instability and increased risk of mesenchymal cancers. Mutations in the RECQL4 gene, encoding a protein of the family of Werner (WRN) and Bloom (BLM) helicases, have been identified in a subset of RTS patients. Apart from congenital poikiloderma, the clinical presentation of RTS is widely variable, raising the question of the possible existence of a second locus. Results herein reported on a sporadic Caucasian patient emphasize the concept that mutation analyses at both DNA and RNA level complement the genetic defect suggested by clinical and cytogenetic signs. The patient presented with typical congenital poikiloderma and bone defects and exhibited significant genomic instability in the peripheral blood karyotype. By RECQL4 DNA mutation analysis, he was found to carry a 1473delT (mut 5) on one allele and an AG to AC change at the 3′‐splice site of exon 13 (a variant of mut 4) on the second allele. RT‐PCR analysis of RECQL4 cDNA encompassing the entire helicase domain showed diffuse splicing defects indicating that the loss of a single 3′‐splice signal motif disregulates the correct splice‐site selection and affects the overall RNA processing. The presence of an unstable minisatellite which ends at 3′‐splice site of IVS12 may enhance the mutation at this site. This genomic feature together with a number of short introns in the RECQL4 gene may account for the common missplicing of RECQL4 mRNA. While it is possible that defects of RECQL4 mRNA processing might account for part of the clinical variability observed for this syndrome, only a thorough analysis at both genomic and RNA level may allow a genotype–phenotype correlation in RTS patients, restricting the search of a second RTS locus to the specific patients. © 2003 Wiley‐Liss, Inc.
Morphology of the 45,X embryo: An embryoscopic study
Authors: Philipp Tom , Kalousek Dagmar K. 
Published: June 2003

AbstractThe morphology of monosomy X in embryos was documented by means of transcervical embryoscopy prior to evacuation in 24 cases of missed abortion. The embryos ranged in size from 13 mm to 26 mm CRL and were all developed beyond the sixth week of development. The embryonic phenotype varied from nearly normal to obviously abnormal with a combination of localized external developmental defects consisting of microcephaly, facial dysplasia, and retarded limb development. A single case of encephalocele was observed. The factors responsible for the wide range of developmental defects observed in monosomy X embryos are currently unknown. Transcervical embryoscopy can serve as a central component for further genetic studies elucidating these mechanisms which are needed for reaching a further understanding of the developmental effects of specific aneuploidy in human morphogenesis. © 2003 Wiley‐Liss, Inc.
Alcoholic neuropathy is clinicopathologically distinct from thiamine‐deficiency neuropathy
Authors: Koike Haruki , Iijima Masahiro , Sugiura Makoto , Mori Keiko , Hattori Naoki , Ito Hiroki , Hirayama Masaaki , Sobue Gen 
Published: June 2003

AbstractCharacteristics of alcoholic neuropathy have been obscured by difficulty in isolating them from features of thiamine‐deficiency neuropathy. We assessed 64 patients with alcoholic neuropathy including subgroups without (ALN) and with (ALN‐TD) coexisting thiamine deficiency. Thirty‐two patients with nonalcoholic thiamine‐deficiency neuropathy (TDN) also were investigated for comparison. In ALN, clinical symptoms were sensory‐dominant and slowly progressive, predominantly impairing superficial sensation (especially nociception) with pain or painful burning sensation. In TDN, most cases manifested a motor‐dominant and acutely progressive pattern, with impairment of both superficial and deep sensation. Small‐fiber‐predominant axonal loss in sural nerve specimens was characteristic of ALN, especially with a short history of neuropathy; long history was associated with regenerating small fibers. Large‐fiber‐predominant axonal loss predominated in TDN. Subperineurial edema was more prominent in TDN, whereas segmental de/remyelination resulting from widening of consecutive nodes of Ranvier was more frequent in ALN. Myelin irregularity was greater in ALN. ALN‐TD showed a variable mixture of these features in ALN and TDN. We concluded that pure‐form of alcoholic neuropathy (ALN) was distinct from pure‐form of thiamine‐deficiency neuropathy (TDN), supporting the view that alcoholic neuropathy can be caused by direct toxic effect of ethanol or its metabolites. However, features of alcoholic neuropathy is influenced by concomitant thiamine‐deficiency state, having so far caused the obscure clinicopathological entity of alcoholic neuropathy. Ann Neurol 2003
Early ischemic lesion recurrence within a week after acute ischemic stroke
Authors: Kang Dong‐Wha , Latour Lawrence L. , Chalela Julio A. , Dambrosia James , Warach Steven 
Published: June 2003

AbstractPrevious observations suggested that multiple ischemic lesions on diffusion‐weighted imaging (DWI) are common in acute stroke patients. We hypothesized that a source of these multiple lesions was the recurrence of ischemic lesions within a week after a clinically symptomatic stroke. We analyzed 99 acute ischemic stroke patients scanned within 6 hours of onset and at subsequent times within the first week. Ischemic lesion recurrence was defined as any new lesion separate from the index lesion. Recurrent lesions occurring outside initial perfusion deficit were termed ‘distant lesion recurrence’. We estimated the hazard ratio (HR) of recurrence associated with clinical and imaging characteristics using log‐rank test. Any lesion recurrence was found in 34%, with distant lesion recurrence in 15%, while clinical recurrence was evident in 2%. Initial multiple DWI lesions were associated with any lesion recurrence (HR, 2.83; 95% confidence interval [CI], 1.65–10.29; p = 0.002) and with distant lesion recurrence (HR, 5.99; 95% CI, 4.05–64.07; p < 0.0001). Large‐artery atherosclerosis was the most frequent stroke subtype associated with any lesion recurrence (p = 0.026). These results may indicate a prolonged state of increased ischemic risk over the first week and suggest DWI as a possible surrogate measure for recurrent stroke. Ann Neurol 2003
Impaired sequence learning in carriers of the DYT1 dystonia mutation
Authors: Ghilardi Maria‐Felice , Carbon Maren , Silvestri Giulia , Dhawan Vijay , Tagliati Michele , Bressman Susan , Ghez Claude , Eidelberg David 
Published: June 2003

AbstractPrevious positron emission tomography (PET) studies have shown that nonmanifesting carriers of the DYT1 dystonia mutation express an abnormal pattern of resting glucose metabolism. To determine whether motor behavior is impaired in these subjects, we compared movement and sequence learning in 12 clinically unaffected DYT1 carriers with 12 age‐matched controls. Regional differences in brain function during task performance were assessed with simultaneous H215O/PET. We found that motor performance was similar in the DYT1 and control groups, with no significant differences in movement time and spatial accuracy measured during each of the tasks. In contrast, sequence learning was reduced in gene carriers relative to controls (p < 0.01). PET imaging during motor execution showed increased activation in gene carriers (p < 0.001, uncorrected) in the left premotor cortex and right supplementary motor area, with concomitant reduction in the posterior medial cerebellum. During sequence learning, activation responses in DYT1 carriers were increased in the left ventral prefrontal cortex, and lateral cerebellum. These findings suggest that abnormalities in motor behavior and brain function exist in clinically nonmanifesting DYT1 carriers. Although localized increases in neural activity may enable normal movement execution in these subjects, this mechanism may not compensate for their defect in sequence learning. Ann Neurol 2003;54:102–109
Quantitative analysis of cortical pyramidal neurons after corpus callosotomy
Authors: Jacobs Bob , Creswell Johanna , Britt Jonathan P. , Ford Kevin L. , Bogen Joseph E. , Zaidel Eran 
Published: June 2003

AbstractThis study quantitatively explored the dendritic/spine extent of supragranular pyramidal neurons across several cortical areas in two adult male subjects who had undergone a callosotomy several decades before death. In all cortical areas, there were numerous atypical, supragranular pyramidal neurons with elongated “tap root” basilar dendrites. These atypical cells could be associated with an underlying epileptic condition and/or could represent a compensatory mechanism in response to deafferentation after callosotomy. Ann Neurol 2003
Solid‐state polymerization of poly(trimethylene terephthalate)
Authors: Duh Ben 
Published: July 2003

AbstractThe solid‐state polymerization (SSP) of poly(trimethylene terephthalate) (PTT) has been studied and compared with that of poly(ethylene terephthalate) (PET). Because PTT and PET share the same SSP mechanism, the modified second‐order kinetic model, which has successfully been used to describe the SSP behaviors of PET, also fits the SSP data of PTT prepolymers with intrinsic viscosities (IVs) ranging from 0.445 to 0.660 dL/g. According to this model, the overall SSP rate is −dC/dt = 2ka(C − Cai)2, where C is the total end group concentration, t is the SSP time, ka is the apparent reaction rate constant, and Cai is the apparent inactive end group concentration. With this equation, the effects of all factors that influence the SSP rate are implicitly and conveniently incorporated into two parameters, ka and Cai. ka increases, whereas Cai decreases, with increasing SSP temperature, increasing prepolymer IV, and decreasing pellet size, just as for the SSP of PET. Therefore, the SSP rate increases with increasing prepolymer IV and increasing SSP temperature. The apparent activation energy is about 26 kcal/mol, and the average SSP rate about doubles with each 10°C increase in temperature within the temperature range of 200–225°C. The SSP rate increases by about 30% when the pellet size is decreased from 0.025 to 0.015 g/pellet. Compared with PET, PTT has a much lower sticking tendency and a much higher SSP rate (more than twice as high). Therefore, the SSP process for PTT can be made much simpler and more efficient than that for PET. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3188–3200, 2003
Crosslinking reaction of epoxy resin (diglycidyl ether of bisphenol A) by anionically polymerized polycaprolactam: I. Mechanism and optimization
Authors: Gupta Alka , Singhal Reena , Nagpal A. K. 
Published: July 2003

AbstractDifferent ratios of epoxy resin, diglycidyl ether of bisphenol A (DGEBA) and ϵ‐caprolactam (starting from 10:90 DGEBA and vice versa), were used to synthesize reactive DGEBA and polycaprolactam blends by the anionic polymerization of ϵ‐caprolactam at 140°C. Anionic polymerization was conducted with a strong base such as sodium hydride as a catalyst along with a cocatalyst such as N‐acetyl caprolactam. The reaction mechanism, possible cure reactions, and reaction conditions of the reactive blends were studied with Fourier transform infrared spectroscopy and differential scanning calorimetry. The experiments were carried to study the optimization ratio and the effect of the composition on properties such as hardness and tensile strength of the reactive blends. The DGEBA was crosslinked by polycaprolactam through the reaction of the oxirane group with the amide nitrogen, and the reaction was very fast. A ratio of 80:20 (DGEBA:ϵ‐caprolactam) was optimum, and the resulting blend showed the highest tensile strength and hardness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3237–3247, 2003
Temperature‐sensitive membranes prepared by the plasma‐induced graft polymerization of N‐Isopropylacrylamide into porous polyethylene membranes
Authors: Huang Jian , Wang Xiaolin , Chen Xiuzhen , Yu Xuehai 
Published: July 2003

AbstractA temperature‐responsive polymer, poly(N‐isopropylacrylamide) (PNIPAAm), was grafted onto porous polyethylene membranes by a plasma‐induced graft polymerization technique. A wide range of grafting was achieved through variations in the grafting conditions, including the postpolymerization temperature, time, monomer concentration, and graft‐reaction medium. The active species induced by plasma treatment was proven to be long‐living via a postpolymerization time of 95 h. Different solvent compositions, that is, water, methanol, benzene, and water/methanol, were used as reaction media, and water showed a much higher polymerization rate than the organic solvents. Based on the hydrophilicity of the active species, a mechanism explaining the solvent effect in plasma‐induced graft polymerization was examined. Characterizations by scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), and micro Fourier transform infrared showed that the grafted polymers were located on both the outer surface and inside pores of the membranes. The XPS analysis also confirmed that the polar amide groups tended to distribute more outward when grafted PNIPAAm was in its expanding state than when it was in its shrinking state. Water permeation experiments showed that the permeability of the grafted membranes varied dramatically with a slight temperature change in the vicinity of the lower critical solution temperature (LCST) of PNIPAAm. The effective pore radii of the grafted membranes above and below the LCST could be depicted by Hagen‐Poiseuille's law. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3180–3187, 2003
Thermal stability and crystallization kinetics of isotactic polypropylene/organomontmorillonite nanocomposites
Authors: He Ji‐Dong , Cheung Man Ken , Yang Ming‐Shu , Qi Zongneng 
Published: July 2003

AbstractThe thermal stability and crystallization kinetics of isotactic polypropylene (iPP) and iPP/organomontmorillonite (organo‐MMT) nanocomposites were investigated with differential scanning calorimetry and thermogravimetry. The incorporation of organo‐MMT up to a concentration of 4 wt % did not affect the melting temperature of iPP but did increase the peak thermal degradation temperature by 60°C. The isothermal crystallization kinetics showed that the addition of organo‐MMT increased the crystallization rate of iPP but reduced the isothermal Avrami exponent. The crystallization temperature of the nanocomposites measured with nonisothermal crystallization was higher than that of plain iPP, and this indicated an enhanced crystallization rate. The nonisothermal Avrami exponent, like the isothermal exponent, decreased with the addition of organo‐MMT, and this suggested changes in the crystallite growth geometry. Subsequently, the tensile yield strength and the tensile modulus both increased, but the elongation at break and the notched Izod impact strength did not change significantly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3404–3415, 2003
Raman spectroscopic studies on the structural changes of electrosynthesized polypyrrole films during heating and cooling processes
Authors: Chen Fengén , Zhang Jiaxin , Wang Fan , Shi Gaoquan 
Published: July 2003

AbstractPolypyrrole films were electrochemically synthesized by direct oxidative polymerization of pyrrole in acetonitrile containing β‐naphthalene sulfonic acid or tetrabutylammonium tetrafluoroborate as an supporting electrolyte. We characterized the as‐grown polypyrrole films by resonance Raman spectroscopy in the temperature region of −195 to 275°C. During the heating process, the Raman bands related to the oxidized species decreased gradually, due mainly to the affect of oxygen and moisture in the air, and, finally, the neutral polymer chains decomposed into disordered carbons. During the cooling process, polymer chains changed from disordered (coil‐like) to ordered (rodlike) structures and caused the elongation of the conjugated chain length. This results in a red shift of the absorption of the electron spectra of the polymer and the enhancements of the Raman bands related to the oxidized species. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3390–3395, 2003
Sorption, diffusion, and permeation of esters, aldehydes, ketones, and aromatic liquids into tetrafluoroethylene/propylene at 30, 40, and 50°c
Authors: Kulkarni Sangeeta B. , Kariduraganavar Mahadevappa Y. , Aminabhavi Tejraj M. 
Published: July 2003

AbstractThe coefficients of sorption, diffusion, and permeation for five organic esters, three aldehydes, one cyclic ketone, and three substituted aromatic liquids have been calculated for tetrafluoroethylene/propylene copolymer membranes at 30, 40, and 50°C with the sorption–gravimetric technique. With the sorption data, the concentration‐independent diffusion coefficients have been calculated from Fick's diffusion equation. Analytical solutions of Fick's equation under suitable boundary conditions have been obtained so that the liquid concentration profiles in the polymeric membranes at different times and different depths of liquid penetration could be computed. Because of the linearly increasing trend of the diffusion coefficients with temperature, efforts have been made to estimate Arrhenius parameters. Experimental values and the computed quantities have been used to determine the membrane–solvent interactions and to propose suitable applications for the membranes under investigation in various situations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3201–3209, 2003
Postnatal myosin heavy chain isoforms in prenatal porcine skeletal muscles: Insights into temporal regulation
Authors: da Costa Nuno , McGillivray Christine , Chang Kin‐Chow 
Published: July 2003

AbstractOur knowledge of the temporal expression of postnatal (adult) fast myosin heavy chain (MyHC) isoforms (2a, 2x, and 2b) in prenatal muscles is limited. Using the pig as a target species and large‐animal model, we report on the qualitative and quantitative expression of the major post‐ and prenatal MyHC isoforms during gestation, as determined by TaqMan real‐time PCR and immunohistochemistry. We found that postnatal fast MyHC mRNAs and proteins were expressed much earlier in the pig (gestation day 35) than was previously reported in small mammals. There was a high degree of coexpression and colocalisation of pre‐ and postnatal MyHC mRNAs and proteins in prenatal muscles. During a period of prenatal muscle growth (gestation days 35–77), relative expression of MyHC isoforms (embryonic > 2a > 2x > 2b) correlated with the gene order in the skeletal MyHC cluster, which suggests the possible presence of cis‐acting elements on the same side as the MyHC embryonic gene associated with temporal regulation. Anat Rec Part A 273A:731–740, 2003. © 2003 Wiley‐Liss, Inc.
Ultrastructural aspects of the follicular cells of the pars tuberalis in bats related to the seasonal cycle
Authors: Azzali Giacomo , Arcari Maria Luisa , Spaggiari Brunella , Romita Giuseppina 
Published: July 2003

AbstractThe topography and structure of the follicular cells and the follicular cavity of the hypophyseal pars tuberalis (PT) were studied in adult hibernating bats (Pipistrellus pipistrellus and Rhinolophus ferrumequinum) of both sexes, during the annual seasonal cycle and the reproductive cycle. The follicular cells were found to be organized around a central cavity. They showed a polyhedral shape and apical microvilli protruding into central cavities. During hibernation, the follicular cells showed active cytoplasmic organelles, clusters of glycogen particles, and lipid droplets. In the supranuclear cytoplasm, 9+2 type cilia, some dense bodies, microvesicular vacuoles, and thin actin‐like filaments (rather scarce during autumn) were detected. The contents of the follicular cavity showed well‐defined ultrastructural seasonal characteristics, with a colloid‐like aspect during awakening and a strongly granular aspect during autumn oestrus and mating. Positive staining for PAS and paraldehyde fuchsin, and a marked reaction to lectins PHA‐L4, MAM, and RCA 60 suggested the presence of sialo‐glycoproteins in the follicular cavities. Both follicular and endocrine PT‐specific cells appeared to mark the boundary of follicular cavities. This finding suggests that the follicular cavity contents are comprised of both types of cells, rather than by cell fragmentation or degeneration products. Anat Rec Part A 273A:763–771, 2003. © 2003 Wiley‐Liss, Inc.
The changing face of scientific discourse: Analysis of genomic and proteomic database usage and acceptance
Authors: Brown Cecelia 
Published: June 2003

AbstractThe explosion of the field of molecular biology is paralleled by the growth in usage and acceptance of Web‐based genomic and proteomic databases (GPD) such as GenBank and Protein Data Bank in the scholarly communication of scientists. Surveys, case studies, analysis of bibliographic records from Medline and CAPlus, and examination of “Instructions to Authors” sections of molecular biology journals all confirm the integral role of GPD in the scientific literature cycle. Over the past 20 years the place of GPD in the culture of molecular biologists was observed to move from tacit implication to explicit knowledge. Originally journals suggested deposition of data in GDP but by the late1980s, the majority of journals mandated deposition of data for a manuscript to be accepted for publication. A surge subsequently occurred in the number of articles retrievable from Medline and CAPlus using the keyword “GenBank”. GPD were not found to a new form of publication, but rather a fundamental storage and retrieval mechanism for vast amounts of molecular biology information that support the creation of scientific intellectual property. For science to continue to advance, scientists unequivocally agreed that GDP must remain free of peer‐review and available at no charge to the public. The results suggest that the existing models of scientific communication should be updated to incorporate GDP data deposition into the current continuum of scientific communication.
Teaching a simple meal preparation skill to adults with moderate and severe mental retardation using video modeling
Authors: Rehfeldt Ruth Anne , Dahman Dana , Young Amanda , Cherry Hollie , Davis Paula 
Published: June 2003

AbstractWe evaluated whether adults with mental retardation in the moderate or severe range would acquire simple meal preparation skills via video modeling. Training was conducted in the kitchen of the participants' day treatment setting. The intervention consisted of (i) watching a video of an adult with a developmental disability making a peanut butter and jelly sandwich and (ii) receiving verbal praise for each step of the task that was performed correctly. All three participants mastered the task and demonstrated generalization across settings. All three participants also demonstrated maintenance of the skill one month following mastery. Copyright © 2003 John Wiley & Sons, Ltd.