bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?
Authors: Fisk John E. , Montgomery Catharine , Wareing Michelle , Murphy Philip N. 
Published: August 2006

AbstractThe research evidence regarding the potential effects of ecstasy suggests that it may be neurotoxic and that its use is associated with cognitive impairment. In recent years evidence has emerged suggesting that cannabinoids, the active ingredients in cannabis, can be neuroprotective under certain conditions. Given that many ecstasy users also consume cannabis at the same time, the possibility emerges that these individuals might be less susceptible to ecstasy‐related impairment. The present paper reanalyses the data from a number of previous studies, contrasting the performance of those individuals who generally consume cannabis and ecstasy at the same time with those who generally consume ecstasy on its own. The two ecstasy‐using groups are compared with non‐ecstasy users on a range of measures including processing speed, random letter generation, verbal and visuo‐spatial working memory span, reasoning and associative learning. The two ecstasy user groups did not differ significantly from each other on any of the measures. Both user groups were significantly worse than non‐ecstasy users on measures of associative learning, verbal and visuo‐spatial working memory and reasoning. The results suggest that consuming cannabis at the same time as ecstasy does not reduce the likelihood of cognitive impairment. Copyright © 2006 John Wiley & Sons, Ltd.
Electronic structure of CO—An exercise in modern chemical bonding theory
Authors: Frenking Gernot , Loschen Christoph , Krapp Andreas , Fau Stefan , Strauss Steven H. 
Published: August 2006

AbstractThis paper discusses recent progress that has been made in the understanding of the electronic structure and bonding situation of carbon monoxide which was analyzed using modern quantum chemical methods. The new results are compared with standard models of chemical bonding. The electronic charge distribution and the dipole moment, the nature of the HOMO and the bond dissociation energy are discussed in detail. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Dispersion and repulsion contributions to the solvation free energy: Comparison of quantum mechanical and classical approaches in the polarizable continuum model
Authors: Curutchet Carles , Orozco Modesto , Luque F. Javier , Mennucci Benedetta , Tomasi Jacopo 
Published: August 2006

AbstractWe report a systematic comparison of the dispersion and repulsion contributions to the free energy of solvation determined using quantum mechanical self‐consistent reaction field (QM‐SCRF) and classical methods. In particular, QM‐SCRF computations have been performed using the dispersion and repulsion expressions developed in the framework of the integral equation formalism of the polarizable continuum model, whereas classical methods involve both empirical pairwise potential and surface‐dependent approaches. Calculations have been performed for a series of aliphatic and aromatic compounds containing prototypical functional groups in four solvents: water, octanol, chloroform, and carbon tetrachloride. The analysis is focused on the dependence of the dispersion and repulsion components on the level of theory used in QM‐SCRF computations, the contribution of those terms in different solvents, and the magnitude of the coupling between electrostatic and dispersion–repulsion components. Finally, comparison is made between the dispersion–repulsion contributions obtained from QM‐SCRF calculations and the results determined from classical approaches. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Software news and updates carma: A molecular dynamics analysis program
Authors: Glykos Nicholas M. 
Published: August 2006

AbstractA computer program has been developed to aid the analysis of molecular dynamics trajectories. The program is tuned for macromolecular large‐scale problems and supports features such as removal of global translations‐rotations of the solute, calculation of average distance maps and their corresponding standard deviations, calculation of the variance‐covariance and cross‐correlation matrices, and principal component analysis of trajectories with the added ability to create artificial trajectories based on selected eigenvectors. Limited graphics (trajectory viewing) capabilities are also available. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Photochemistry of CH3Mn(CO)5: A multiconfigurational ab initio study
Authors: González Leticia , Daniel Chantal 
Published: August 2006

AbstractThe electronic spectroscopy of CH3Mn(CO)5 has been investigated by means of ab initio multiconfigurational MS‐CASPT2/CASSCF calculations. The absorption spectrum is characterized by a series of Metal‐Centered (MC) excited states in the UV energy domain (below 290 nm) that could be responsible for the observed photoreactivity starting at 308 nm. The upper part of the spectrum is overcrowded between 264 and 206 nm and dominated by a high density of Metal‐to‐Ligand‐Charge‐Transfer (MLCT) states corresponding mainly to 3dMn → π*CO excitations. A non‐negligible contribution of Metal‐to‐σ‐Bond‐Charge‐Transfer (MSBCT) states corresponding to 3dMn → σ*Mn‐CH3 excitations is also present in the theoretical spectrum of CH3Mn(CO)5. However, in contrast to other transition metal hydrides and methyl substituted (HMn(CO)5, HCo(CO)4, and CH3Co(CO)4) these MSBCT transitions do not participate to the lowest bands of the spectrum as main contributions. The photochemistry of CH3Mn(CO)5, namely the loss of a CO ligand vs. the metal‐methyl bond homolysis, is investigated by means of MS‐CASPT2 states correlation diagrams. This study illustrates the complexity of the photodissociation mechanism of this class of molecules, which involves a large number of nearly degenerate electronic states with several channels for fragmentation. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Theoretical mechanistic study on the radical–molecule reactions of cyanomethylidyne with PH3, H2S, and HCl
Authors: Wang Jian , Ding Yi‐Hong , Sun Chia‐Chung 
Published: August 2006

AbstractThe cyanomethylidyne (CCN) has been the long‐standing subject of extensive theoretical and experimental studies on its structures and spectroscopies. However, there are few investigations on its reactivity. Our very recent theoretical work indicated that even with the simplest methane, the CCN reaction faces almost zero barriers following the carbyne mechanism as CH does. This was suggestive of the powerfulness of the nonatomic and nonhydrogenated CCN radical in depleting old molecules and synthesizing new cyanogen‐containing molecules in either combustion or interstellar processes. In this paper, a detailed mechanistic study at the CCSD(T)/6‐311+G(2df,p)//B3LYP/6‐311g(d,p) and G2M(CC1)//B3LYP/6‐311G(d,p) computational levels is reported for the reactions of CCN with a series of σ‐bonded molecules of the second row HnX (X,n) = (P,3), (S,2), and (Cl,1). The carbenoid insertion is confirmed as the most favored entrance channel, forming Hn−1XC(H)CN. Subsequently, Hn−1XC(H)CN will predominantly lead to product Hn−2XC(H)CN+H via the H‐extrusion processes (except X = Cl). Yet, the CCN+HX (X = Cl) reaction is the exception because XC(H)CN intrinsically has no H‐atoms at X for extrusion or migration. At G2M(CC1)//B3LYP/6‐311G(d,p) computational level, ClC(H)CN can only dissociate back to the reactant or be stabilized with its isomers upon sufficient collisions or radiation. The carbyne character confirmed in this paper provides a useful base for future experimental and theoretical study on the chemistry of this nonatomic and nonhydrogenated reactive radical. In addition, interestingly, the complexes HnX‐CCN (X,n) = (P,3) and (S,2) formed in the reactions are found not to be the simple (loosely bound) donor–accepter complexes as those formed in the CCN insertions into other hydrides (NH3, H2O, HF, HCl).On the basis of the comparison with the qualitative features of typical ylides, H3PCCN and H2SCCN are considered to be similar to the ylides in nature, being “ylide‐like radicals.” They might be observed in some experiments, since they are in deep potential wells on the energy surface. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Explicit factorization of external coordinates in constrained statistical mechanics models
Authors: Echenique Pablo , Calvo Iván 
Published: August 2006

AbstractIf a macromolecule is described by curvilinear coordinates or rigid constraints are imposed, the equilibrium probability density that must be sampled in Monte Carlo simulations includes the determinants of different mass‐metric tensors. In this work, the authors explicitly write the determinant of the mass‐metric tensor G and of the reduced mass‐metric tensor g, for any molecule, general internal coordinates and arbitrary constraints, as a product of two functions; one depending only on the external coordinates that describe the overall translation and rotation of the system, and the other only on the internal coordinates. This work extends previous results in the literature, proving with full generality that one may integrate out the external coordinates and perform Monte Carlo simulations in the internal conformational space of macromolecules. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Electrophysiological abnormalities precede apparent histological demyelination in the central nervous system of mice overexpressing proteolipid protein
Authors: Tanaka Hisataka , Ikenaka Kazuhiro , Isa Tadashi 
Published: August 2006

AbstractMyelin proteolipid protein (plp), a major myelin protein in the CNS, has been proposed to function in myelin assembly. Transgenic mice overexpressing the plp gene by introduction of two extra wild‐type (Wt) mouse plp genes (plptg/–) exhibit normal myelination and ion channel clustering at the age of 2 months. However, at the age of 5 months, demyelination becomes observable, accompanied by a reduction in the number of K+ channel clusters at Ranvier's node and a progressive increase in motor deficit. To clarify how these age‐dependent changes are related to nerve conduction in the CNS, we analyzed the conduction velocity (CV) and relative refractory period (RRP) of identified spinal ascending or descending tracts, such as the dorsal column pathway, the vestibulospinal and reticulospinal tracts, and the pyramidal tract, in plptg/– mice 2, 5, and 8 months of age. We found that CVs decreased as age increased. Importantly, CVs were significantly reduced and prolonged RRPs were observed in 2‐month‐old (2M) plptg/– mice that had no apparent demyelination. Immunohistological examination revealed that densities of Na+ and K+ channel clusters decreased as plptg/– and Wt mice aged. However, a clear correlation was not observed between CVs and mean channel cluster densities or between mean channel cluster densities and progress of demyelination. Performance in the rotarod test was normal in 2M plptg/– mice but deteriorated in mice older than age 5 months. These results suggest that electrophysiological analysis can detect the abnormalities of the plptg/– mice earlier than histological or behavioral measures. © 2006 Wiley‐Liss, Inc.
D‐β‐hydroxybutyrate protects dopaminergic SH‐SY5Y cells in a rotenone model of Parkinson's disease
Authors: Imamura Keiko , Takeshima Takao , Kashiwaya Yoshihiro , Nakaso Kazuhiro , Nakashima Kenji 
Published: August 2006

AbstractIt has been postulated that the pathogenesis of Parkinson's disease (PD) is associated with mitochondrial dysfunction. Rotenone, an inhibitor of mitochondrial complex I, provides models of PD both in vivo and in vitro. We investigated the neuroprotective effect of D‐β‐hydroxybutyrate (bHB), a ketone body, against rotenone toxicity by using SH‐SY5Y dopaminergic neuroblastoma cells. SH‐SY5Y cells, differentiated by all‐trans‐retinoic acid, were exposed to rotenone at concentrations ranging from 0 to 1,000 nM. We evaluated cellular oxidation reduction by the alamarBlue assay, viability by lactate dehydrogenase (LDH) assay, and survival/death ratio by live/dead assays. Exposure to rotenone for 48 hr oxidized cells and decreased their viability and survival rate in a concentration‐dependent manner. Pretreatment of cells with 8 mM bHB provided significant protection to SH‐SY5Y cells. Whereas rotenone caused the loss of mitochondrial membrane potential, released cytochrome c into the cytosol, and reduced cytochrome c content in mitochondria, addition of bHB blocked this toxic effect. bHB also attenuated the rotenone‐induced activation of caspase‐9 and caspase‐3. Administration of 0–10 mM 3‐nitropropionic acid, a complex II inhibitor, also decreased the reducing power of SH‐SY5Y cells measured by alamarBlue assay. Pretreatment with 8 mM bHB attenuated the decrease of alamarBlue fluorescence. These data demonstrated that bHB had a neuroprotective effect that supported the mitochondrial respiration system by reversing the inhibition of complex I or II. Ketone bodies, the alternative energy source in the mammalian brain, appear to have therapeutic potential in PD. © 2006 Wiley‐Liss, Inc.
Restoration of growth plate function following radiotherapy is driven by increased proliferative and synthetic activity of expansions of chondrocytic clones
Authors: Horton Jason A. , Margulies Bryan S. , Strauss Judith A. , Bariteau Jason T. , Damron Timothy A. , Spadaro Joseph A. , Farnum Cornelia E. 
Published: August 2006

AbstractRadiation therapy encompassing an active epiphysis can negatively impact the potential for bone growth by disrupting cell‐cycle progression and accelerating apoptosis and terminal differentiation in physeal chondrocytes. Despite functional derangement following radiation exposure, the irradiated growth plate retains a capacity for regeneration and recovery of growth. The purpose of this study was to characterize the initial sequence of events leading to functional growth recovery in irradiated weanling rat growth plates. We hypothesized that growth in an irradiated epiphysis would be partially restored due to the expansion of chondrocytic clones. Stereological histomorphometry was used to compare chondrocytic cell and matrix turnover between the first and second week following irradiation, and to determine the relative contribution of each of the cellular and extracellular matrix (ECM) compartments to growth. We found that restoration of growth in the irradiated limb was strongly associated with the proliferative activity and production of ECM by these chondrocytic clones, as they expand in average volume, but not in numerical density. We conclude that chondrocytes forming expansive clones and exhibiting increased mitotic and matrix synthesis activity initiate the early restoration of function in the irradiated growth plate, and would be a logical target for strategies to restore full growth potential. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1945–1956, 2006
The role of surgery in treatment of stage IV melanoma
Authors: Young Shawn E. , Martinez Steve R. , Essner Richard 
Published: August 2006

AbstractThe prognosis for patients with melanoma has not improved over the last 30 years. So far, almost without exception, clinical trials conducted with single or multiple agent chemotherapy, biological therapy (interferon‐alpha, interleukin‐2), and biochemotherapy have failed to demonstrate consistent survival benefit. Without effective alternate treatments, surgery must be considered the primary treatment of melanoma, independent of disease stage. Although surgery is clearly favored as the treatment of localized melanoma, consensus opinion and clinician preference become divided once melanoma progresses beyond its primary site. Many physicians will adopt an attitude of resignation and hesitancy when treating metastatic melanoma. As a result, patients with advanced disease are often treated with medications that produce little survival or palliative benefit at the expense of significant toxicity. Numerous studies have demonstrated clear and durable survival advantages for patients undergoing complete resection of metastatic melanoma. Further, surgical resection can produce an immediate decrease in tumor burden with minimal morbidity and mortality at a reasonable cost. J. Surg. Oncol. 2006;94:344–351. © 2006 Wiley‐Liss, Inc.
Mohs micrographic surgery in the treatment of lentigo maligna and melanoma
Authors: Temple Claire L.F. , Arlette John P. 
Published: August 2006

AbstractBackground and ObjectivesThe treatment of lentigo maligna (LM) and lentigo maligna melanoma (LMM) is challenging due to lesion location, size, patient age, and potential for recurrence and spread. The largest studies to date confirm that for melanocytic tumours, MMS provides high local control rates while minimizing tissue loss. Herein we report our local control rate for melanoma treated by MMS over a decade.MethodsCharts were reviewed on all patients with melanocytic tumors treated by a single physician (JPA) using MMS over the time period of 1993–2002. Demographic, surgical and pathological details were recorded. Patients were followed for local, regional and distant recurrences.ResultsThe patient population was comprised of 199 patients with 202 melanomas. There were 69 invasive lesions, with a mean Breslow depth of 0.92 mm (0.2–3.6 mm). The mean number of levels required to clear the lesions was 2.7 (1–7), resulting in a mean defect size of 11.8 cm2 (0.9–70.7 cm2). Patients with LMM were significantly older (73.2 vs. 66.5 yrs, p = 0.012) and had larger defects after MMS (16.74 cm2 vs. 10.27 cm2) than patients with LM. At a mean follow‐up of 29.8 months, there were no local recurrences, four regional recurrences, and two distant recurrences.ConclusionMMS is an effective modality for the clearance of melanocytic tumors. J. Surg. Oncol. 2006;94:287–292. © 2006 Wiley‐Liss, Inc.
Expression of DPC4/Smad4 gene in stone‐containing intrahepatic bile duct
Authors: Lee King‐Teh , Chang Wen‐Tsan , Wang Shen‐Nien , Chuang Shih‐Chang , Chai Chee‐Yin , Hu Shih‐Wen 
Published: August 2006

AbstractBackground and ObjectivesHepatolithiasis is etiologically related to cholangiocarcinoma. We underwent this study with an attempt to examine the expression of DPC4/Smad4 gene in stone‐containing intrahepatic bile ducts (IHD) and intrahepatic cholangiocarcinoma (ICC).Patients and MethodsThe immunohistochemical method and RT‐PCR analysis were used to study the expression of DPC4/Smad4 gene in normal IHD, stone‐containing IHD, and ICC. All the specimens were from hepatic resection.ResultsThe immunohistochemical study showed that all specimens from 24 normal IHD had marked expression of DPC4/Smad4 gene, while there was 4.4% (2/46) and 33.3% (3/9) loss of DPC4/Smad4 expression in stone‐containing IHD and ICC, respectively. Among the specimens of stone‐containing IHD, all the hyperplastic epithelial cells showed normal expression of DPC4/Smad4 gene while dysplastic epithelial cells showed 20% (2/10) loss expression of DPC4/Smad4. The RT‐PCR analysis showed that the normal IHD had the highest content of DPC4/Smad4 mRNA, which was threefold and sixfold higher than that of stone‐containing IHD and ICC, respectively.ConclusionLoss expression of DPC4/Smad4 gene was found both in stone‐containing IHD and ICC. Dysplastic epithelium of stone‐containing IHD had higher potential for malignant transformation. J. Surg. Oncol. 2006;94:338–343. © 2006 Wiley‐Liss, Inc.
Number of lymph node metastases and its prognostic significance in early gastric cancer: A multicenter italian study
Authors: Roviello Franco , Rossi Simone , Marrelli Daniele , Pedrazzani Corrado , Corso Giovanni , Vindigni Carla , Morgagni Paolo , Saragoni Luca , de Manzoni Giovanni , Tomezzoli Anna 
Published: August 2006

AbstractBackground and ObjectivesThis study was aimed at evaluating the prognostic significance of the number of metastatic nodes in early gastric cancer (EGC).MethodsIn this multicenter retrospective study 652 cases of resected EGC were analyzed. We searched for lymph node metastases‐associated risk factors and to identify subsets of patients with different prognosis according to the number of involved nodes.ResultsNodal involvement was observed in 14.1%. A significant correlation was found between the presence of node metastases and tumor size (RR 1.34, P = 0.001), submucosal invasion (RR: 3.14, P = 0.007), Lauren diffuse/mixed type (RR: 4.88, P < 0.001) and Kodama Pen A type (RR: 4.59, P < 0.001). The 10‐year survival rate was 92% for N0 cases, 82% and 73% for tumors with one to three and four to six positive nodes while it dropped to 27% with more than six metastatic nodes. Interestingly enough, the 10‐year risk of recurrence diminished with the increasing number of retrieved nodes (>15) even in N0 patients.ConclusionsNodal involvement confirmed to be a significant prognostic factor. In view of the trend to a lower risk of recurrence when more than 15 nodes were retrieved and the better staging achieved we consider D2 lymphadenectomy the treatment of choice. J. Surg. Oncol. 2006;94:275–280. © 2006 Wiley‐Liss, Inc.
Lymphatic spread and microinvolvement in adenocarcinoma of the esophago‐gastric junction
Authors: Schurr Paulus G. , Yekebas Emre F. , Kaifi Jussuf T. , Lasch Steffi , Strate Tim , Kutup Asad , Cataldegirmen Guel , Bubenheim Michael , Pantel Klaus , Izbicki Jakob R. 
Published: August 2006

AbstractBackgroundAdenocarcinoma of the esophago‐gastric junction (EGJ) potentially spreads to abdominal and mediastinal lymph nodes.MethodsEighty‐five patients with type I and II EGJ cancer underwent curative esophagectomy or esophago‐gastrectomy and radical abdominal and mediastinal lymphadenectomy. Microinvolvement was detected with the mAb Ber‐Ep4 in all histopathologically free lymph nodes.ResultsIn type I tumors (n = 40), lower mediastinal lymph nodes were positive in 24% and among type II tumors (n = 45) in 10% of patients. Ber‐Ep4+ cells in apparently free lymph nodes were found in 49% of patients. On inclusion of Ber‐Ep4+ nodes, positive mediastinal lymph node staging was rising to 40 and 33% in type I and II patients, respectively. After a median observation time of 27.1 months, 37 of 85 patients (43.5%) had died of tumor disease. Kaplan–Meier analysis revealed a significant impact of nodal microinvolvement on disease‐specific survival for type I and type II tumors (P = 0.016 and P < 0.001, respectively). Cox regression analysis revealed a 2.77 higher independent risk (P = 0.002) for nodal microinvolvement.ConclusionsLymphatic microinvolvement shows a high incidence in curatively resected EGJ cancer. Spread to mediastinal lymph nodes seems to necessitate lymphadenectomy of the thoracic cavity in either type. J. Surg. Oncol. 2006;94:307–315. © 2006 Wiley‐Liss, Inc.