bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Electrochemistry of Catalase at a Gold Electrode Modified with Single‐Wall Carbon Nanotubes
Authors: Wang Liang , Wang Jianxiu , Zhou Feimeng 
Published: April 2004

AbstractThe direct electrochemistry of catalase (Ct) was accomplished at a gold electrode modified with single‐wall carbon nanotubes (SWNTs). A pair of well‐defined redox peaks was obtained for Ct with the reduction peak potential at −0.414 V and a peak potential separation of 32 mV at pH 5.9. Both reflectance FT‐IR spectra and the dependence of the reduction peak current on the scan rate revealed that Ct adsorbed onto the SWNT surfaces. The redox wave corresponds to the Fe(III)/Fe(II) redox center of the heme group of the Ct adsorbate. Compared to other types of carbonaceous electrode materials (e.g., graphite and carbon soot), the electron transfer rate of Ct redox reaction was greatly enhanced at the SWNT‐modified electrode. The peak current was found to increase linearly with the Ct concentration in the range of 8×10−6–8×10−5 M used for the electrode preparation and the peak potential was shown to be pH dependent. The catalytic activity of Ct adsorbates at the SWNTs appears to be retained, as the addition of H2O2 produced a characteristic catalytic redox wave. This work demonstrates that direct electrochemistry of redox‐active biomacromolecules such as metalloenzymes can be improved through the use of carbon nanotubes.
Inhibition of solid tumor growth by gene transfer of VEGF receptor‐1 mutants
Authors: Heidenreich Regina , Machein Marcia , Nicolaus Anke , Hilbig Andreas , Wild Carola , Clauss Matthias , Plate Karl H. , Breier Georg 
Published: April 2004

AbstractVascular endothelial growth factor (VEGF) and the high‐affinity VEGF receptor Flk‐1/KDR (VEGFR‐2) are key regulators of tumor angiogenesis. Strategies to block VEGF/VEGFR‐2 signaling were successfully used to inhibit experimental tumor growth and indicated that VEGFR‐2 is the main signaling VEGF receptor in proliferating tumor endothelium. Here, we investigated the role of the VEGF receptor‐1 (VEGFR‐1/Flt‐1) in the vascularization of 2 different experimental tumors in vivo. VEGFR‐1 mutants were generated that lack the intracellular tyrosine kinase domain. Retrovirus‐mediated gene transfer of the VEGFR‐1 mutants led to a strong reduction of tumor growth and angiogenesis in xenografted C6 glioma and in syngeneic BFS‐1 fibrosarcoma. Histological analysis of the inhibited fibrosarcoma revealed reduced vascular density, decreased tumor cell proliferation as well as increased tumor cell apoptosis and the formation of necrosis. The retroviral gene transfer of the full length VEGFR‐1 also caused a significant reduction of tumor growth in both models. The inhibitory effects of the VEGFR‐1 mutants and the full length VEGFR‐1 in BFS‐1 fibrosarcoma were mediated through host tumor endothelial cells because the BFS‐1 fibrosarcoma cells were not infected by the retrovirus. The formation of heterodimers between VEGFR‐2 and full length or truncated VEGFR‐1 was observed in vitro and might contribute to the growth inhibitory effect by modulating distinct signal transduction pathways. The results of our study underline the central role of the VEGF/VEGFR‐1 signaling system in tumor angiogenesis and demonstrate that VEGFR‐1 can serve as a target for anti‐angiogenic gene therapy. © 2004 Wiley‐Liss, Inc.
Peptide nucleic acid clamp PCR: A novel K‐ras mutation detection assay for colorectal cancer micrometastases in lymph nodes
Authors: Taback Bret , Bilchik Anton J. , Saha Sukamal , Nakayama Takahiro , Wiese David A. , Turner Roderick R. , Kuo Christine T. , Hoon Dave S. B. 
Published: April 2004

AbstractInaccurate staging of colorectal cancer (CRC) has been attributed to the failure to detect lymph node metastases by conventional pathology. We have previously reported the use of lymphatic mapping to accurately identify those lymph nodes most likely to harbor micrometastatic disease and permit focused pathologic examination. Mutation of K‐ras allele at codons 12 or 13 occurs frequently in early stages of CRC development. The purpose of our study was to assess sentinel lymph nodes (SLN) for occult CRC micrometastases using a unique peptide nucleic acid (PNA) clamp PCR assay specific for K‐ras mutations. Seventy‐two paraffin‐embedded primary CRC and paired SLN were evaluated by PNA clamp PCR for K‐ras mutations. Thirty primary tumors (42%) were positive for K‐ras mutations, and in 5 of these cases the SLN were positive for metastases by Hematoxylin and Eosin staining. PNA clamp PCR identified occult metastases in an additional 6 patients, upstaging 24% of K‐ras positive primary CRCs (p = 0.014). No K‐ras mutations were detected among the 20 noncancer lymph nodes assessed. This study demonstrates the utility, specificity and sensitivity of PNA clamp PCR assay in identifying occult micrometastases in the SLN of CRC patients by single‐base mutation analysis. © 2004 Wiley‐Liss, Inc.
Mutation analysis of the RECQL4 gene in sporadic osteosarcomas
Authors: Nishijo Koichi , Nakayama Tomitaka , Aoyama Tomoki , Okamoto Takeshi , Ishibe Tatsuya , Yasura Ko , Shima Yasuko , Shibata Kotaro R. , Tsuboyama Tadao , Nakamura Takashi , Toguchida Junya 
Published: April 2004

AbstractOsteosarcoma (OS) is the most prevalent malignant tumor among cases of Rothmund‐Thomson syndrome (RTS) with germline mutations of the RECQL4 gene, a member of the RecQ helicase family. We investigated the involvement of the RECQL4 gene in the development of OS unrelated to RTS. RECQL4 mRNA was detected in 9 of 9 OS cell lines by Northern blotting and 26 of 26 OS tumors by RT‐PCR. Direct sequencing of the entire coding region along with flanking splice junctions and 13 small (<100 bp) introns in 71 OS tumors revealed 2 sites with a single‐base change causing an amino acid change (G1814A for R355Q and C2474T for P441S) and one site with a 6 bp inframe deletion (4837‐42delTGCACC for CT857‐8del). Identical genotypes were found in corresponding normal tissues in all cases, and the frequency of each allele was not significantly different between OS and control populations. Our data indicate that the RECQL4 gene is not a frequent target for somatic mutations in sporadic OS unrelated to RTS. © 2004 Wiley‐Liss, Inc.
Stuttering and gait disturbance after supplementary motor area seizure
Authors: Chung Sun J. , Im Joo‐Hyuk , Lee Jae‐Hong , Lee Myoung C. 
Published: April 2004

AbstractAcquired stuttering is an uncommon speech disorder. Supplementary motor area (SMA) lesions have been reported to be directly or indirectly related to acquired stuttering and various types of motor dysfunction. We report on a patient who presented with both acquired stuttering and long‐lasting gait disturbance after SMA seizure. © 2004 Movement Disorder Society
Persistent abnormal shoulder elevation after accessory nerve injury and differential diagnosis with post‐traumatic focal shoulder‐elevation dystonia: Report of a case and literature review
Authors: Cossu Giovanni , Melis Maurizio , Melis Giannina , Ferrigno Paola , Molari Andrea 
Published: April 2004

AbstractWe report on a patient with persistent abnormal shoulder posture associated with isolated neurogenic hypertrophy of the trapezius muscle due to accessory nerve injury. The patient complained of marked difficulty in shoulder elevation and abduction. Over 6‐month treatment with botulinum toxin, there was a complete resolution © 2004 Movement Disorder Society
Pramipexole‐treated Parkinson's disease during pregnancy
Authors: Mucchiut Marco , Belgrado Enrico , Cutuli Daniela , Antonini Angelo , Bergonzi Paolo 
Published: April 2004

AbstractThere are few reports about drug‐related effects on PD pregnancy. We describe the case of a woman affected by PD treated with pramipexole monotherapy during pregnancy. The child, born by caesarean delivery, is healthy, whereas motor disability of the mother progressively increased to the point that levodopa therapy was necessary. © 2004 Movement Disorder Society
Composite vascularized skin/bone graft model: A viable source for vascularized bone marrow transplantation
Authors: Siemionow Maria , Ulusal Betul G. , Ozmen Selahattin , Ulusal Ali E. , Ozer Kagan 
Published: April 2004

AbstractIn this study, we introduce a new model for vascularized skin and bone marrow transplantation. Twenty‐five Lewis (RT11) rats were studied. Anatomic dissection studies were performed in 5 animals. In the experimental group, 10 isograft transplantations were performed between Lewis rats. Combined groin skin and femoral bone flaps were transplanted based on the femoral artery and vein. Transplants were evaluated on a daily basis. All flaps survived without problems over 100 days posttransplant. The skin component remained pink and pliable, and grew new hair. Histological examination of the femoral bone (except the femoral head) revealed active hematopoiesis with a viable compact and cancellous bone components on day 100 posttransplant. This model can be applied to tolerance induction studies across the major Histocompatibility (MHC) barrier, where bone will serve as donor of stem and progenitor cells, and the skin flap will serve as a monitor of graft rejection. © 2004 Wiley‐Liss, Inc.
Glucose, lactate, and pyruvate response in an experimental model of microvascular flap ischemia and reperfusion: A microdialysis study
Authors: Setälä Leena P. , Korvenoja E. Maj‐lén , Härmä Markku A. , Alhava Esko M. , Uusaro Ari V. , Tenhunen Jyrki J. 
Published: April 2004

AbstractEarly diagnosis of postoperative perfusion failure is essential in microsurgical tissue transfer. In order to determine if microdialysis could be used in diagnosing flap ischemia, we tested this method in an experimental pig model. Sixty‐six flaps (34 myocutaneous and 29 cutaneous) were created in 18 anesthetized pigs. During the experiment, secondary ischemia was induced for 5 h by selective clamping of the artery (20 flaps) or vein (21 flaps). Glucose, lactate, and pyruvate concentrations were measured hourly from the muscular and dermal layers. We found that decreasing glucose levels and increasing lactate concentrations were associated with arterial and venous occlusions from the first hour of ischemia. In venous ischemia, lactate concentrations remained lower than those in arterial ischemia. The increase in lactate‐to‐pyruvate and lactate‐to‐glucose ratios was related to ischemia and also discriminated arterial occlusion from venous occlusion. In conclusion, microdialysis can be used to facilitate early detection of ischemia. © 2004 Wiley‐Liss, Inc.
Gravimetric determination of the diffusion characteristics of polymers using small specimens
Authors: Cervenka A. J. , Young R. J. , Kueseng K. 
Published: April 2004

AbstractAn investigation has been undertaken of the factors controlling the rate of ingress of water into relatively small epoxy specimens. The application of a three‐dimensional diffusion model, fully acknowledging that the specimen geometry controls the rate of ingress, has successfully resolved the problems of determining the diffusion characteristics—the diffusion coefficient D and the uptake M∞ corresponding to saturation—and making theoretical predictions of the uptake Mt by small specimens. On the theoretical front, simulations have been carried out to demonstrate that (1) theoretical predictions require two equations to be used to obtain correct relative uptake Mt/M∞ values for short and long exposure times; (2) a cube of the side h is saturated faster than an infinite slab of the thickness h, and (3) determination of the D value by applying the model derived for an infinite slab to specimens of finite dimensions results in an apparent value that may grossly exceed the true diffusion coefficient. On the experimental front, suggestions are made regarding (4) elimination of a systematic error that might be introduced by single weighing of a specimen prior exposure, (5) determination of the product M∞ D1/2 from the gravimetry data for short exposure times, and (6) splitting this product into absolute values D and M∞ by means of a minimization procedure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42:2122–2128, 2004
Impact of targeted‐volume ventilation on lung inflammatory response in preterm infants with respiratory distress syndrome (RDS)
Authors: Lista G. , Colnaghi M. , Castoldi F. , Condò V. , Reali R. , Compagnoni G. , Mosca F. 
Published: April 2004

AbstractVolutrauma and pulmonary inflammation are thought to be the most important predisposing factors of chronic lung disease (CLD), a major complication of prematurity. A new option in patient‐triggered ventilation (PTV), the volume guarantee (VG), a volume‐targeted ventilation, seems to be a promising approach in reducing the risk of CLD, by limiting lung inflammatory injury and volutrauma. Our aim was to evaluate lung inflammatory response in preterm infants with respiratory distress syndrome (RDS), mechanically ventilated with and without VG, as measured by proinflammatory cytokines (IL‐6, IL‐8, and TNF‐α) in tracheobronchial aspirate (TA) fluid. Fifty‐three preterm infants (GA = 25–32 weeks) with RDS were randomized at birth to be ventilated using pressure support ventilation (PSV) with VG (Vt = 5 ml/kg) (n = 30) and without VG (n = 23) (Draeger Babylog 8000 Plus, 5.n). IL‐6, IL‐8, and TNF‐α were determined by ELISA in TA samples on days 1, 3, and 7 of life. We observed a significant difference (ANOVA) in IL‐8 and IL‐6 levels on day 3 between the two groups (P < 0.05), and an increasing significative trend in IL‐8 values in PSV group (P < 0.05). Mechanical ventilation lasted longer in the PSV group (12.3 ± 3 vs. 8.8 ± 3 days) (P = no significance). In conclusion, these preliminary data suggest a role for volume‐targeted ventilatory strategy in reducing acute inflammatory response in preterm infants with RDS. Further studies are required in order to define whether this ventilatory strategy prevents lung injury. Pediatr Pulmonol. 2004; 37:510–514. © 2004 Wiley‐Liss, Inc.
Sex differences among children 2–13 years of age presenting at the emergency department with acute asthma
Authors: Schatz Michael , Clark Sunday , Emond Jennifer A. , Schreiber Donald , Camargo Carlos A. 
Published: April 2004

AbstractHospitalization rates for asthma have been reported to be higher in males than females in children under age 15, but it is not clear whether this disparity reflects gender differences in prevalence, severity, or treatment. We performed a prospective cohort study as part of the Emergency Medicine Network. Patients aged 2–13 years who presented to the emergency department (ED) with acute asthma underwent a structured interview in the ED and another by telephone 2 weeks later. Of 1,602 patients, 61% (95% CI, 59–64%) were boys. Girls were slightly older than boys, although no material differences existed in acute presentation, chronic asthma characteristics, ED treatment, or ED course. There was no difference in admission rates for boys or girls (20% vs. 22%; P = 0.48). This finding persisted when adjusting for other factors in a multivariate logistic regression model. No sex differences were observed for relapse or ongoing exacerbation on univariate or multivariate analysis. These data suggest that asthma is not inherently more severe in boys with asthma compared to girls, and that the increased rate of hospitalizations in boys under age 13 is due to differences in prevalence, not severity. Pediatr Pulmonol. 2004; 37:523–529. © 2004 Wiley‐Liss, Inc.
Androgen receptor (AR) expression in AR‐negative prostate cancer cells results in differential effects of DHT and IGF‐I on proliferation and AR activity between localized and metastatic tumors
Authors: Plymate Stephen R. , Tennant Marie K. , Culp Stephen H. , Woodke Lillie , Marcelli Marco , Colman Ilsa , Nelson Peter S. , Carroll Julie M. , Roberts Charles T. , Ware Joy L. 
Published: April 2004

AbstractBackgroundTwo features of the progression from organ‐confined to metastatic prostate cancer are dysregulation of the androgen receptor (AR) and a decrease in insulin‐like growth factor‐type‐I receptor (IGF‐IR) expression. The purpose of this study was to determine the effect of changes in IGF‐IR expression on AR activity.MethodsM12 human prostate cells were stably transfected with an AR expression construct to produce the M12‐AR parental (PAR) cell line. PAR cells were implanted orthotopically into nude mice and M12‐AR primary (PRI) cell lines were derived from intraprostatic tumors and metastatic cell lines (MET) were derived from PRI tumors that had metastasized to diaphragm or lung.ResultsTumor formation in the prostate by PAR cells was decreased significantly compared to M12 controls. PAR, PRI, and MET cells expressed equivalent amounts of AR protein; however, IGF‐IR expression was increased significantly in PAR and PRI cells. IGF‐IR expression decreased in MET lines to the levels seen in M12 control cells. IGF‐I significantly enhanced dihydrotestosterone (DHT)‐stimulated, but not basal, AR transcriptional activity in PRI cells. In MET cells, IGF‐I significantly suppressed DHT‐stimulated transcriptional activity. In MET cells in which the IGF‐IR was re‐expressed from a retroviral vector, the effects of DHT and IGF‐I on AR activity were similar to those seen in PRI cells.ConclusionsThis study demonstrates that the changes in IGF‐IR expression exhibited by this model of metastatic progression cause significant alterations in AR signaling and suggest that this interaction may be an important aspect of the changes seen in AR function in disease progression in vivo. © 2004 Wiley‐Liss, Inc.
Quantitative analysis of eight testosterone metabolites using column switching and liquid chromatography/tandem mass spectrometry
Authors: Magnusson Mats O. , Sandström Rikard 
Published: April 2004

AbstractThe rate at which testosterone is metabolized to different singly hydroxylated metabolites has been widely used as an in vitro marker for activity of different CYP450 enzymes. The interest in extra‐hepatic metabolism, e.g. due to metabolism in the gut wall, has increased during the last decade. Measurement of extra‐hepatic enzyme activity using testosterone as a substrate requires a highly sensitive analytical method. A new liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) method, using column switching for online cleaning and desalting of samples, was developed and validated for analysis of 2α‐, 2β‐, 6α‐, 6β‐, 7α‐, 16α‐, and 16β‐hydroxytestosterone and androstenedione. The samples were injected on a SB‐CN column and detection was performed using MS/MS. The limits of quantification ranged from 0.3 to 3.33 nM for the different metabolites. The validated method was used to quantify the enzyme activity in rat intestine mucosa. The formation rates of 16α‐, 16β‐hydroxytestosterone and androstenedione were quantified, and 2β‐and 6β‐hydroxytestosterone were formed above the limits of detection. Copyright © 2004 John Wiley & Sons, Ltd.
Improved sensitivity for insulin in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry by premixing α‐cyano‐4‐hydroxycinnamic acid matrix with transferrin
Authors: Kobayashi Tetsu , Kawai Hiroshi , Suzuki Takuo , Kawanishi Toru , Hayakawa Takao 
Published: April 2004

AbstractThis report describes an enhancement of the signal intensities of proteins and peptides in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). When α‐cyano‐4‐hydroxycinnamic acid (CHCA) premixed with human transferrin (Tf) was used as a matrix, the signal intensity of insulin was amplified to more than ten times that of the respective control in CHCA without Tf. The detection limit of insulin was 0.39 fmol on‐probe in the presence of Tf, while it was 6.3 fmol in the absence of Tf. The signal intensity of insulin was also enhanced when the CHCA matrix was premixed with proteins other than Tf (80 kDa), such as horse ferritin (20 kDa), bovine serum albumin (BSA, 66 kDa), or human immunoglobulin G (150 kDa). The optimum spectrum of insulin was obtained when the added amount of protein was in the range 0.26–0.62 pmol, regardless of the molecular weight of the added protein. Tf and BSA outperformed the other tested proteins, as determined by improvements in the resulting spectra. When the mass spectra of several peptides and proteins were recorded in the presence of Tf or BSA, the signal intensities of large peptides such as glucagon were enhanced, though those of smaller peptides were not enhanced. In addition, the signal enhancement achieved with Tf and BSA was more pronounced for the proteins, including cytochrome C, than for the large peptides. This enhancement effect could be applied to improve the sensitivity of MALDI‐TOFMS to large peptides and proteins. Copyright © 2004 John Wiley & Sons, Ltd.
Logarithmic expected packet delivery delay in mobile ad hoc wireless networks
Authors: del Rio Heberto , Sarkar Dilip 
Published: April 2004

AbstractIt has been shown that in a mobile ad hoc wireless network per node throughput remains constant as the number of nodes approaches infinity, when the nodes lie in a disk of unit area. However, this requires that some packets are delivered indirectly by a relay node. In this paper, we prove, in the same setup, that D(k) ∈ Θ(log k), where D(k) is the expected delay time of a mobile ad hoc wireless network with k nodes. As consequence, we have concluded that mobile ad hoc wireless networks are not scalable for real‐time applications. Copyright © 2004 John Wiley & Sons, Ltd.
Quality of life in schizophrenics with and without the deficit syndrome
Authors: Gourevitch R. , Abbadi S. , Guelfi J.D. 
Published: April 2004

AbstractWe investigated the relations between deficit as part of schizophrenic symptomatology and the popular but unclear concept of quality of life (QOL). In a 47-patient sample, subjective QOL was compared in schizophrenics with and without the deficit syndrome. Self- and hetero-rated QOL is more impaired in deficit patients. Differences between deficit and non-deficit groups are more significant as the index used for measuring QOL gets less “behavioral” and more “psycho-pathological”. These results are consistent with existing literature. The “behavioral” dimensions of Heinrichs’ quality of life scale (QLS) are less discriminative between deficit and non-deficit schizophrenics, but they are more independent of the symptoms. They might have a special clinical meaning, which needs to be defined. The concepts of QOL (as used in QLS) and deficit symptomatology are partially redundant. QLS might be an inappropriate, or at least un-specific measure of QOL.