bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thromboembolism prophylaxis during laparoscopic cholecystectomy
Authors: Bradbury A W , Chan Y-C , Darzi A , Stansby G 
Published: June 2006

Abstract

Background
The aim of this study was to determine current UK practice with regard to thromboembolism prophylaxis during laparoscopic cholecystectomy.

Methods
Postal questionnaires were sent to 800 members of the Association of Surgeons; replies were received from 551 surgeons (69 per cent) of whom 417 practised laparoscopic cholecystectomy.

Results
Heparin was prescribed to all patients by 74 per cent, and selectively by 20 per cent, of respondents. Surgeons who performed fewer than ten laparoscopic cholecystectomies per annum were significantly less likely to use heparin (P &lt; 0·001) and more likely to believe that heparin produces significant adverse bleeding (P &lt; 0·01). Thirty per cent of respondents used low molecular weight heparin. Stockings to deter thromboembolism were used by 74 per cent, and pneumatic compression by 37 per cent. Indications for heparin varied considerably and were not influenced by Thromboembolic Risk Factors (THRIFT) guidelines. Only 20 per cent of respondents considered that thromboembolism was a problem; 91 per cent reported that they had never experienced a thromboembolic complication following laparoscopic cholecystectomy.

Conclusion
The rate of thromboembolism after laparoscopic cholecystectomy is unknown but most surgeons believe the risk is very low. Surgeons' attitudes towards thromboembolism prophylaxis are variable, but most experienced surgeons use low-dose heparin.
Sequential arterial and portal vein embolizations before right hepatectomy in patients with cirrhosis and hepatocellular carcinoma
Authors: Ogata S , Belghiti J , Farges O , Varma D , Sibert A , Vilgrain V 
Published: June 2006

Abstract

Background
Selective transarterial chemoembolization (TACE) and portal vein embolization (PVE) could improve the rate of hypertrophy of the future liver remnant (FLR) in patients with chronic liver disease. This study evaluated the feasibility and efficacy of this combined procedure.

Methods
Between November 1998 and October 2004, 36 patients with cirrhosis and hepatocellular carcinoma underwent right hepatectomy after PVE. Additional TACE preceded PVE by 3–4 weeks in 18 patients (TACE + PVE group) and the remaining 18 patients had PVE alone (PVE group).

Results
PVE was well tolerated in all patients. The mean increase in percentage FLR volume was significantly higher in the TACE + PVE group than in the PVE group (mean(s.d.) 12(5) versus 8(4) per cent; P = 0·022). The rate of hypertrophy was more than 10 per cent in 12 patients in the TACE + PVE group and in five who had PVE alone (P = 0·044). Duration of surgery, blood loss, incidence of liver failure and mortality (two patients in each group) were similar in the two groups. None of the 17 patients with an increase in FLR volume of more than 10 per cent died, whereas there were four deaths among 19 patients with a smaller increase. The incidence of complete tumour necrosis was significantly higher in the TACE + PVE group (15 of 18 versus one of 18; P &lt; 0·001), with a higher 5-year disease-free survival rate (37 versus 19 per cent; P = 0·041).

Conclusion
Sequential TACE and PVE before operation increases the rate of hypertrophy of the FLR and leads to a high rate of complete tumour necrosis associated with longer recurrence-free survival.
Social deprivation and outcomes in colorectal cancer
Authors: Smith J J , Tilney H S , Heriot A G , Darzi A W , Forbes H , Thompson M R , Stamatakis J D , Tekkis P P 
Published: June 2006

Abstract

Background
The aim of this study was to examine the influence of social deprivation on postoperative mortality and length of stay in patients having surgery for colorectal cancer.

Methods
Data were extracted from the Association of Coloproctology of Great Britain and Ireland database of patients presenting between April 2001 and March 2002. The effect of social deprivation, measured by the Townsend score, on 30-day postoperative mortality and length of stay was evaluated by two-level hierarchical regression analysis.

Results
A total of 7290 (86·8 per cent) patients underwent surgery. Operative mortality was 6·7 per cent and median length of stay 11 days. Deprivation indices were significantly higher in patients with Dukes' ‘D’ cancers, undergoing emergency surgery and with higher American Society of Anesthesiologists (ASA) grades (P &lt; 0·005). Worsening deprivation was associated with higher operative mortality and longer stay (P = 0·014). For each unit increase in deprivation, there was 2·9 (95 per cent confidence interval 0·5 to 5·2) per cent increase in 30-day mortality. On multifactorial analysis, social deprivation was an independent predictor of length of stay, but its effect on operative mortality was explained by differences in ASA grade, operative urgency and Dukes' classification.

Conclusion
Social deprivation was an independent risk factor of postoperative length of stay and associated with higher postoperative mortality. These results have important implications for risk modelling of postoperative outcomes.
Artificial ascites technique for percutaneous radiofrequency ablation of liver cancer adjacent to the gastrointestinal tract
Authors: Kondo Y , Yoshida H , Shiina S , Tateishi R , Teratani T , Omata M 
Published: June 2006

Abstract

Background
Percutaneous radiofrequency ablation (RFA) of liver tumours adjacent to the gastrointestinal tract is controversial. This study assessed the value of an intraperitoneal water infusion (artificial ascites) technique for percutaneous RFA of such tumours.

Methods
Before ablation in 52 patients (55 treatments, 58 tumours), between 250 and 3000 (mean 681) ml 5 per cent glucose solution was infused into the abdominal cavity using a 14-G needle, with the aim of preventing thermal injury by separating the liver from the gastrointestinal tract.

Results
There were no adverse events associated with the artificial ascites technique. In 43 (78 per cent) of the 55 treatments, the liver and gastrointestinal tract were separated successfully. In the other 12 treatments, in which the separation was not confirmed by real-time ultrasonography, there was one case of perforation of the ascending colon after RFA; adhesion of the liver and colon resulting from previous laparotomy may have been related to the injury.

Conclusion
Production of artificial ascites can be undertaken safely, making RFA safe and effective for hepatic tumours adjacent to the gastrointestinal tract. In patients with possible postoperative adhesions, confirmation of separation of the liver from surrounding organs is mandatory to avoid thermal injury.
Patterns of lymph node spread of cutaneous squamous cell carcinoma of the head and neck
Authors: Vauterin Tom J. , Veness Michael J. , Morgan Garry J. , Poulsen Michael G. , O'Brien Christopher J. 
Published: June 2006

AbstractBackground.Among patients with cutaneous squamous cell carcinoma (SCC) of the head and neck, recent studies have shown that those with involvement of the parotid gland also have a high incidence of neck node involvement. Treatment of the neck by either surgery or radiotherapy is therefore recommended among patients with parotid SCC, even if clinical examination is negative. The aim of this study was first to analyze patterns of metastatic spread in the parotid and cervical lymph nodes and then to correlate the pattern of involved nodes with the primary cutaneous site in order to guide the appropriate extent of surgery, should neck dissection be used to treat the neck in patients with parotid SCC.Methods.A cohort of 209 patients with cutaneous SCC of the head and neck and clinically evident regional metastatic disease was reviewed retrospectively from 3 Australian institutions. The distribution of involved nodes was obtained from pathology reports; the anatomic sites of primary cutaneous cancers were then correlated with these findings.Results.Among 209 patients, 171 (82%) had clinical parotid involvement. Of these, 28 had clinical neck disease, whereas 143 had parotid disease alone. Thirty‐eight (18%) patients had neck disease only. A total of 199 patients were treated surgically, whereas 10 received radiotherapy alone. Surgery included 172 parotidectomies and 151 neck dissections (93 of which were elective). Primary sites were cheek (21.7%), pinna (20.4%), temple (15.8%), forehead (15.8%), postauricular region (5.9%), neck (5.3%), anterior scalp (5.3%), posterior scalp (3.3%), periorbital (3.3%), nose (2.6%), and chin (0.6%). Among pathologically positive necks, level II was most frequently involved (79%). Level IV (13%) and level V (17%) were only involved in extensive lymph node disease, the exception being for isolated level V metastases from the posterior scalp.Conclusions.Primary sites were mainly localized to the lateral aspect of the head. Among patients with cutaneous SCC involving the parotid and neck, level II was the most commonly involved neck level. The distribution of involved nodes suggests that in a patient with parotid involvement and a clinically negative neck with an anterolateral primary, a supraomohyoid neck dissection, always including the external jugular lymph node(s) would be appropriate. In the case of a posterior primary, level V should be dissected as well. In patients with parotid SCC and a clinically positive neck, a comprehensive neck dissection is recommended. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Regulation of intracellular Ca2+by P2Y1receptors may depend on the developmental stage of cultured rat striatal neurons
Authors: Rubini Patrizia , Pinkwart Christina , Franke Heike , Gerevich Zoltan , Nörenberg Wolfgang , Illes Peter 
Published: June 2006

AbstractMixed striatal cell cultures containing neurons and glial cells were grown either in neurobasal medium (NBM) or Dulbecco's modified Eagle's medium (DMEM). Whole‐cell patch‐clamp recordings indicated that, if at all, only a single, low amplitude spike was evoked shortly after starting the injection of a depolarizing current pulse into NBM neurons. In contrast, DMEM neurons fired series of high amplitude action potentials, without apparent spike frequency adaptation. The possible reason for the observed action potential failure in NBM neurons was a low density of Na+channels per unit of membrane surface area. However, both in NBM and DMEM neurons, ATP did not induce inward current responses via P2X receptor‐channels, although GABAAandN‐methyl‐D‐aspartate (NMDA) receptor‐channels could be activated by muscimol and NMDA, respectively. Ca2+imaging experiments by means of the Fura‐2 method were utilized to measure intracellular Ca2+([Ca2+]i) in neurons and glial cells. NBM, but not DMEM neurons responded to ATP with [Ca2+]itransients; glial cells grown in either culture medium were equally sensitive to ATP. ATP caused an increase of [Ca2+]iby a mechanism only partly dependent on external Ca2+; the residual ATP effect was blocked by cyclopiazonic acid (CPA) and was therefore due to the release of Ca2+from its intracellular pools. The receptor involved was characterized by P2 receptor antagonists (PPADS, MRS 2179, AR‐C69931MX) and was found to belong to the P2Y1subtype. CPA caused an early [Ca2+]iresponse due to release from intracellular storage sites, followed by a late [Ca2+]iresponse due to the influx of this cation from the extracellular space, probably triggered by the opening of store‐operated channels (SOCs) in the plasma membrane. It is concluded that in partial analogy with the effect of CPA, ATP releases [Ca2+]ivia the Gq/phospholipase C/inositoltrisphosphate (IP3) pathway, thereby opening SOCs. It is hypothesized that this effect of ATP may have an important role for the proliferation and migration of striatal neuronal progenitors. J. Cell. Physiol. 209: 81–93, 2006. © 2006 Wiley‐Liss, Inc.
Boundary element‐free method for fracture analysis of 2‐D anisotropic piezoelectric solids
Authors: Liew K. M. , Sun Yuzhou , Kitipornchai S. 
Published: June 2006

AbstractThis paper considers a 2‐D fracture analysis of anisotropic piezoelectric solids by a boundary element‐free method. A traction boundary integral equation (BIE) that only involves the singular terms of order 1/r is first derived using integration by parts. New variables, namely, the tangential derivative of the extended displacement (the extended displacement density) for the general boundary and the tangential derivative of the extended crack opening displacement (the extended displacement dislocation density), are introduced to the equation so that solution to curved crack problems is possible. This resulted equation can be directly applied to general boundary and crack surface, and no separate treatments are necessary for the upper and lower surfaces of the crack. The extended displacement dislocation densities on the crack surface are expressed as the product of the characteristic terms and unknown weight functions, and the unknown weight functions are modelled using the moving least‐squares (MLS) approximation. The numerical scheme of the boundary element‐free method is established, and an effective numerical procedure is adopted to evaluate the singular integrals. The extended ‘stress intensity factors’ (SIFs) are computed for some selected example problems that contain straight or curved cracks, and good numerical results are obtained. Copyright © 2006 John Wiley & Sons, Ltd.
Fast reactions of arylnitrenium ions with amino acids and proteins: a laser flash photolysis study
Authors: Thomas Selina I. , Falvey Daniel E. 
Published: June 2006

AbstractLaser flash photolysis was used to examine the reaction of N‐methyl‐N‐(4‐biphenylyl)nitrenium ion with various amino acids and proteins in aqueous media. This nitrenium ion was found to react rapidly (>108 M−1 s−1) with tryptophan, tyrosine, methionine and cysteine, more slowly (107–108 M−1 s−1) with lysine, histidine, and arginine. Rapid reaction was also seen with several representative proteins including bovine serum albumin, lysozyme, and chymotrypsin. These results suggest that reaction with proteins is likely to be a significant pathway in the reactions of nitrenium ions generated in vivo. Copyright © 2006 John Wiley & Sons, Ltd.
Structural and functional evolution of transthyretin and transthyretin‐like proteins
Authors: Hennebry Sarah C. , Wright Hannah M. , Likic Vladimir A. , Richardson Samantha J. 
Published: June 2006

AbstractTransthyretin (TTR) is a tetrameric protein involved in the distribution of thyroid hormones in vertebrates. The amino acid sequence of TTR is highly conserved across vertebrates. Hypothetical TTR‐like proteins (TLPs) were inferred from the identification of genes in nonvertebrate species. Here, we identified five motifs defining TLPs and three motifs defining both TTRs and TLPs. These motifs were mapped onto structurally conserved and functionally important regions of TTRs. These motifs were used to build hidden Markov models for accurate identification of TLPs in other organisms. TLPs were divided into three main groups based on their N‐terminal regions. Most TLPs are cytosolic, but in plants and slime mold, we predict they are peroxisomal. We verified that the TLPs from enterobacteria were periplasmic. We demonstrated that TLP genes are expressed in a bacterium (E. coli), an invertebrate animal (C. elegans), and a plant (A. thaliana). These TLPs have similar subunit molecular weights to TTRs, are tetramers, and are predicted to have similar three‐dimensional (3D) structures to TTRs, but do not bind thyroid hormones or similar ligands. We suggest that like TTRs, the N‐terminal and C‐terminal regions of TLPs are integral in defining the function of TLPs in nonvertebrate species and that the TLP gene duplicated in primitive vertebrates to produce the TTR gene. TLP/TTR has retained its overall structure, but changed function and localization during evolution in bacteria, invertebrates, plants, and vertebrates. Proteins 2006. © 2006 Wiley‐Liss, Inc.
An analysis for a cross‐over cohort study with an application to the study of triggers of Menière's disease
Authors: Salim Agus , Becker Niels G. , Möller Jette , Hessén‐Söderman Anne‐Charlotte 
Published: June 2006

AbstractWhen studying the effect of a transient exposure on the risk of a rare illness, for time and cost effectiveness it is desirable to follow a cohort of individuals who are ‘prone’ to the illness over an observation period. In this paper, we present a method of analysis for data arising from such a study. The proposed method can be used to estimate the relative risk of an exposure triggering the illness and the distribution of the time delay from exposure to the onset of illness. The model is extended to include covariate effects and to the situation where there are two types of exposure. For the two types of exposures situation, a model to handle a possible synergism of the exposures is proposed. Finally, the method is applied to study the potential triggers of attacks of Menière's disease. Copyright © 2006 John Wiley & Sons, Ltd.
Conditioning on the propensity score can result in biased estimation of common measures of treatment effect: a Monte Carlo study
Authors: Austin Peter C. , Grootendorst Paul , Normand Sharon‐Lise T. , Anderson Geoffrey M. 
Published: June 2006

AbstractPropensity score methods are increasingly being used to estimate causal treatment effects in the medical literature. Conditioning on the propensity score results in unbiased estimation of the expected difference in observed responses to two treatments. The degree to which conditioning on the propensity score introduces bias into the estimation of the conditional odds ratio or conditional hazard ratio, which are frequently used as measures of treatment effect in observational studies, has not been extensively studied. We conducted Monte Carlo simulations to determine the degree to which propensity score matching, stratification on the quintiles of the propensity score, and covariate adjustment using the propensity score result in biased estimation of conditional odds ratios, hazard ratios, and rate ratios. We found that conditioning on the propensity score resulted in biased estimation of the true conditional odds ratio and the true conditional hazard ratio. In all scenarios examined, treatment effects were biased towards the null treatment effect. However, conditioning on the propensity score did not result in biased estimation of the true conditional rate ratio. In contrast, conventional regression methods allowed unbiased estimation of the true conditional treatment effect when all variables associated with the outcome were included in the regression model. The observed bias in propensity score methods is due to the fact that regression models allow one to estimate conditional treatment effects, whereas propensity score methods allow one to estimate marginal treatment effects. In several settings with non‐linear treatment effects, marginal and conditional treatment effects do not coincide. Copyright © 2006 John Wiley & Sons, Ltd.
Replacement of the positively charged Walker A lysine residue with a hydrophobic leucine residue and conformational alterations caused by this mutation in MRP1 impair ATP binding and hydrolysis
Authors: Buyse Frederic , Hou Yue-xian , Vigano Catherine , Zhao Qing , Ruysschaert Jean-Marie , Chang Xiu-bao 
Published: June 2006

MRP1 (multidrug resistance protein 1) couples ATP binding/hydrolysis at its two non-equivalent NBDs (nucleotide-binding domains) with solute transport. Some of the NBD1 mutants, such as W653C, decreased affinity for ATP at the mutated site, but increased the rate of ATP-dependent solute transport. In contrast, other NBD1 mutants, such as K684L, had decreased ATP binding and rate of solute transport. We now report that mutations of the Walker A lysine residue, K684L and K1333L, significantly alter the tertiary structure of the protein. Due to elimination of the positively charged group and conformational alterations, the K684L mutation greatly decreases the affinity for ATP at the mutated NBD1 and affects ATP binding at the unmutated NBD2. Although K684L-mutated NBD1 can bind ATP at higher concentrations, the bound nucleotide at that site is not efficiently hydrolysed. All these alterations result in decreased ATP-dependent solute transport to approx. 40% of the wild-type. In contrast, the K1333L mutation affects ATP binding and hydrolysis at the mutated NBD2 only, leading to decreased ATP-dependent solute transport to approx. 11% of the wild-type. Consistent with their relative transport activities, the amount of vincristine accumulated in cells is in the order of K1333L≥CFTR (cystic fibrosis transmembrane conductance regulator)&gt;K684L⋙wild-type MRP1. Although these mutants retain partial solute transport activities, the cells expressing them are not multidrug-resistant owing to inefficient export of the anticancer drugs by these mutants. This indicates that even partial inhibition of transport activity of MRP1 can reverse the multidrug resistance caused by this drug transporter.
Proteomic analysis of altered protein expression in skeletal muscle of rats in a hypermetabolic state induced by burn sepsis
Authors: Duan Xunbao , Berthiaume François , Yarmush David , Yarmush Martin L. 
Published: June 2006

mRNA profiling has been extensively used to study muscle wasting. mRNA level changes may not reflect that of proteins, especially in catabolic muscle where there is decreased synthesis and increased degradation. As sepsis is often associated with burn injury, and burn superimposed by sepsis has been shown to result in significant loss of lean tissues, we characterized changes in the skeletal-muscle proteome of rats subjected to a cutaneous burn covering 20% of the total body surface area, followed 2 days later by sepsis induced by CLP (caecal ligation and puncture). EDL (extensor digitorum longus) muscles were dissected from Burn-CLP animals (n=4) and controls (sham-burned and sham-CLP-treated, n=4). Burn-CLP injury resulted in a rapid loss of EDL weight, increased ubiquitin-conjugated proteins and increased protein carbonyl groups. EDL protein profiles were obtained by two-dimensional gel electrophoresis using two immobilized pH gradient strips with overlapping pH range covering a pH 3–8 range. Seventeen spots were significantly altered in the Burn-CLP compared with the control group, representing 15 different proteins identified by peptide mass fingerprinting. The identities of three proteins including transferrin were further confirmed by liquid chromatography–tandem MS. The significant changes in transferrin and HSP27 (heat-shock protein 27) were verified by Western-blot analysis. HSP60, HSP27 and HSPβ6 were down-regulated, along with HSP70, as detected by Western blotting. Six metabolic enzymes related to energy production were also down-regulated. A simultaneous decrease in chaperone proteins and metabolic enzymes could decrease protein synthesis. Furthermore, decreased HSPs could increase oxidative damage, thus accelerating protein degradation. Using cultured C2C12 myotubes, we showed that H2O2-induced protein degradation in vitro could be partially attenuated by prior heat-shock treatment, consistent with a protective role of HSP70 and/or other HSPs against proteolysis.