bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen gradients correlate with cell density and cell viability in engineered cardiac tissue
Authors: Radisic Milica , Malda Jos , Epping Eric , Geng Wenliang , Langer Robert , Vunjak‐Novakovic Gordana 
Published: November 2005

AbstractFor clinical utility, cardiac grafts should be thick and compact, and contain physiologic density of metabolically active, differentiated cells. This involves the need to control the levels of nutrients, and most critically oxygen, throughout the construct volume. Most culture systems involve diffusional transport within the constructs, a situation associated with gradients of oxygen concentration, cell density, cell viability, and function. The goal of our study was to measure diffusional gradients of oxygen in statically cultured cardiac constructs, and to correlate oxygen gradients to the spatial distributions of cell number and cell viability. Using microelectrodes, we measured oxygen distribution in a disc‐shaped constructs (3.6 mm diameter, 1.8 mm thickness) based on neonatal rat cardiomyocytes cultured on collagen scaffolds for 16 days in static dishes. To rationalize experimental data, a mathematical model of oxygen distribution was derived as a function of cell density, viability, and spatial position within the construct. Oxygen concentration and cell viability decreased linearly and the live cell density decreased exponentially with the distance from the construct surface. Physiological density of live cells was present only within the first 128 µm of the construct thickness. Medium flow significantly increased oxygen concentration within the construct, correlating with the improved tissue properties observed for constructs cultured in convectively mixed bioreactors. © 2005 Wiley Periodicals, Inc.
Modeling product formation in anaerobic mixed culture fermentations
Authors: Rodríguez Jorge , Kleerebezem Robbert , Lema Juan M. , van Loosdrecht Mark C.M. 
Published: November 2005

AbstractThe anaerobic conversion of organic matter to fermentation products is an important biotechnological process. The prediction of the fermentation products is until now a complicated issue for mixed cultures. A modeling approach is presented here as an effort to develop a methodology for modeling fermentative mixed culture systems. To illustrate this methodology, a steady‐state metabolic model was developed for prediction of product formation in mixed culture fermentations as a function of the environmental conditions. The model predicts product formation from glucose as a function of the hydrogen partial pressure (PH2), reactor pH, and substrate concentration. The model treats the mixed culture as a single virtual microorganism catalyzing the most common fermentative pathways, producing ethanol, acetate, propionate, butyrate, lactate, hydrogen, carbon dioxide, and biomass. The product spectrum is obtained by maximizing the biomass growth yield which is limited by catabolic energy production. The optimization is constrained by mass balances and thermodynamics of the bioreactions involved. Energetic implications of concentration gradients across the cytoplasmic membrane are considered and transport processes are associated with metabolic energy exchange to model the pH effect. Preliminary results confirmed qualitatively the anticipated behavior of the system at variable pH and PH2 values. A shift from acetate to butyrate as main product when either PH2 increases and/or pH decreases is predicted as well as ethanol formation at lower pH values. Future work aims at extension of the model and structural validation with experimental data. © 2005 Wiley Periodicals, Inc.
Investigation of protein retention and selectivity in HIC systems using quantitative structure retention relationship models
Authors: Ladiwala Asif , Xia Fang , Luo Qiong , Breneman Curt M. , Cramer Steven M. 
Published: November 2005

AbstractIn the present work, the effect of stationary phase resin chemistry and protein physicochemical properties on protein binding affinity in hydrophobic interaction chromatography (HIC) was investigated using linear gradient chromatography and quantitative structure‐retention relationship (QSRR) modeling. Linear gradient experiments were carried out for a set of model proteins on four different HIC resins having different backbone and ligand chemistry. The retention data exhibited significant differences in protein binding affinity, not only across the phenyl and butyl ligand chemistries, but also for the different backbone chemistries found in the Sepharose (cross‐linked agarose) and the Toyopearl 650 M (polymethacrylate) series of resins. QSRR models based on a Support Vector Machine (SVM) approach were developed for the linear retention data using molecular descriptors based on protein crystal structure and primary sequence information as well as a set of new hydrophobicity descriptors based on the solvent accessible protein surface area. The results indicate that the QSRR models were successfully able to capture and selectivity predict the changes observed in these systems. Furthermore, the new descriptors resulted in physically interpretable models of protein retention and provided insights into the factors influencing protein affinity in these different HIC systems. The approach put forth in this study provides a framework for developing predictive tools and for gaining insight into protein selectivity in hydrophobic interaction chromatography. © 2005 Wiley Periodicals, Inc.
Laparoscopic liver resection
Authors: Vibert E , Perniceni T , Levard H , Denet C , Shahri N K , Gayet B 
Published: November 2005

Abstract

Background
This paper describes a 10-year experience of laparoscopic liver surgery, including several major hepatectomies for malignant tumours.

Methods
Of 243 hepatectomies carried out between January 1995 and December 2004, 113 (46·5 per cent) were performed by laparoscopy and 89 were included in this retrospective study.

Results
Twenty-four laparoscopic hepatectomies (27 per cent) were for benign disease and 65 (73 per cent) for malignant tumours, including hepatocellular carcinoma (HCC) in 16 patients and colorectal metastasis (CRM) in 41. Minor hepatectomy was performed in 51 patients and major hepatectomy (three or more Couinaud segments) in 38. Conversion to laparotomy was necessary in 12 patients and perioperative blood transfusion in eight. One patient with cirrhosis who underwent right hepatectomy for HCC with conversion to open surgery died 8 days after surgery. Major morbidity occurred in eight patients (16 per cent) having minor hepatectomy and in 11 (29 per cent) of those having a major resection. The 3-year overall and disease-free survival rates for patients with CRM (mean follow-up 30 months) were 87 (11 patients at risk) and 51 (6 patients at risk) per cent respectively. Corresponding values for patients with HCC (mean follow-up 40 months) were 85 (10 patients at risk) and 68 (5 patients at risk) per cent.

Conclusion
In experienced hands, the results of laparoscopic liver surgery are similar to those for laparotomy.
Meta-analysis of colonic reservoirs versus straight coloanal anastomosis after anterior resection
Authors: Heriot A G , Tekkis P P , Constantinides V , Paraskevas P , Nicholls R J , Darzi A , Fazio V W 
Published: November 2005

Abstract

Background and methods
The comparative benefits and drawbacks of straight coloanal anastomosis (CAA), colonic J-pouch and coloplasty anastomosis after anterior resection are uncertain. Studies published between 1986 and 2005 of colonic J-pouch versus transverse coloplasty or straight CAA were analysed. Endpoints included postoperative complications, and functional and physiological outcomes measured within 6 months, 1 year and 2 years or more after the procedure. A random-effect model was used to aggregate the study endpoints and assess heterogeneity.

Results
Thirty-five studies containing 2240 patients (1066 straight CAA, 1050 J-pouch and 124 coloplasty) were included. There was no significant difference in postoperative complications between the three groups. There was a significant reduction in the frequency of defaecation per day by 1·88, 1·35 and 0·74 motions at the three time intervals in the J-pouch group compared with the straight CAA group. Faecal urgency was less prevalent in patients with a J-pouch than those with a straight CAA (odds ratio 0·27 at 6 months or less and 0·21 at 1 year). There was no difference in functional outcome between J-pouch and coloplasty anastomosis.

Conclusions
The colonic J-pouch provided functional benefits over straight anastomosis with no increase in postoperative complications. Coloplasty appeared to have similar benefits but further studies are required for validation.
Lap‐belt injury with complete avulsion of the spinal cord and cauda equina
Authors: Tubbs R. Shane , Golden Blake , Doyle Scott , Grabb Paul A. , Oakes W. Jerry 
Published: November 2005

AbstractThe authors report a child who was involved in an automobile accident. The patient was restrained by a rear seat lap belt. Radiological examination revealed an L4 Chance‐type fracture and ligamentous disruption at the L4–L5 interval. During superficial dissection of the paraspinal muscles for a spinal fusion procedure, the cauda equina and the lower spinal cord (several centimeters) were visible, completely transected and herniated into the extraspinal space through a disrupted thoracolumbar fascia. The clinician should be aware of the potentially devastating results following a lap‐belt injury in which a Chance fracture is produced. Clin. Anat. 19:665–668, 2006. © 2005 Wiley‐Liss, Inc.
Mechanical contribution of the fibula to torsion stiffness in the lower extremity
Authors: Thambyah A. , Pereira B.P. 
Published: November 2005

AbstractThe role of the fibula in rotational stability of the lower extremity, taking into account the intact knee joint and tibia, to the best of our knowledge, has not been investigated. A cadaver study was designed to determine the torque transfer down the lower extremity, with and without the fibula. Six fresh, frozen human cadaver legs were used. The knee joint was left intact and the foot disarticulated. An external rotation up to 5°, coupled with axial compression, was applied to the femur passing through the knee joint in extension and down the lower extremity to the fixed distal end, where torque (N m) was measured via a load cell. Each specimen was further tested with the fibula, cut 4 cm from the distal end, and finally with the entire fibula disarticulated at the proximal end and removed. To achieve 5° rotation, torques reached 1.82 N m (SD, 0.66 N m). When the fibula was cut, the torque reduced a small yet significant amount of 5%. With the entire fibula removed, the torque reduction was significant and more pronounced at 11%. The fibula provided a small yet significant role in torsion stability. From this study, where the biomechanical characteristics of the fibula is explicated, it is hoped that this information will have use in further understanding the biomechanical role of the fibula, especially, in relation to the altered mechanics associated with lower limb pathology involving a deficient fibula. Clin. Anat. 19:615–620, 2006. © 2005 Wiley‐Liss, Inc.
Design and Synthesis of Oligosaccharides that Interfere with Glycoprotein Quality‐control systems
Authors: Arai Midori A. , Matsuo Ichiro , Hagihara Shinya , Totani Kiichiro , Maruyama Jun‐ichi , Kitamoto Katsuhiko , Ito Yukishige 
Published: November 2005

AbstractCalnexin (CNX) and its soluble homologue calreticulin (CRT) are lectin‐like molecular chaperones that help newly synthesized glycoproteins to fold correctly in the rough endoplasmic reticulum (ER). To investigate the mechanism of glycoprotein‐quality control, we have synthesized structurally defined high‐mannose‐type oligosaccharides related to this system. This paper describes the synthesis of the non‐natural undecasaccharide 2 and heptasaccharide 16, designed as potential inhibitors of the ER quality‐control system. Each possesses the key tetrasaccharide element (Glc1Man3) critical for the CNX/CRT binding, while lacking the pentamannosyl branch required for glucosidase II recognition. These oligosaccharides were evaluated for their ability to bind CRT by isothermal titration calorimetry (ITC). As expected, each of them had a significant affinity towards CRT. In addition, these compounds were shown to be resistant to glucosidase II digestion. Their activities in blocking the chaperone function of CRT were next measured by using malate dehydrogenase (MDH) as a substrate. Their inhibitory effects were shown to correlate well with their CRT‐binding affinities, both being critically dependent upon the presence of the terminal glucose (Glc) residue.
Fluorescent Detection of Apoptotic Cells by Using Zinc Coordination Complexes with a Selective Affinity for Membrane Surfaces Enriched with Phosphatidylserine
Authors: Hanshaw Roger G. , Lakshmi C. , Lambert Timothy N. , Johnson James R. , Smith Bradley D. 
Published: November 2005

AbstractThe appearance of phosphatidylserine on the membrane surface of apoptotic cells (Jurkat, CHO, HeLa) is monitored by using a family of bis(Zn2+‐2,2′‐dipicolylamine) coordination compounds with appended fluorescein or biotin groups as reporter elements. The phosphatidylserine affinity group is also conjugated directly to a CdSe/CdS quantum dot to produce a probe suitable for prolonged observation without photobleaching. Apoptosis can be detected under a wide variety of conditions, including variations in temperature, incubation time, and binding media. Binding of each probe appears to be restricted to the cell membrane exterior, because no staining of organelles or internal membranes is observed.
Synthesis and Properties of Aminopropyl Nucleic Acids
Authors: Zhou Ding , Lagoja Irene M. , Rozenski Jef , Busson Roger , Van Aerschot Arthur , Herdewijn Piet 
Published: November 2005

AbstractOligonucleotides that contain up to three aminopropyl nucleoside analogues have been synthesized. Dimers of aminopropyl adenine and thymidine were prepared and used as building blocks by applying phosphoramidite chemistry. Both R and S isomers of the aminopropyl nucleosides were used. This incorporation led to a reduction of thermal stability of double‐stranded DNA. Furthermore, the (R)‐adenine analogue, which yielded (S)‐APNA, can be considered as a candidate for universal base pairing.
LanV, a Bifunctional Enzyme: Aromatase and Ketoreductase during Landomycin A Biosynthesis
Authors: Mayer Almuth , Taguchi Takaaki , Linnenbrink Anton , Hofmann Carsten , Luzhetskyy Andriy , Bechthold Andreas 
Published: November 2005

AbstractLanV is involved in the biosynthesis of landomycin A. The exact function of this enzyme was elucidated with combinatorial biosynthesis by using Streptomyces fradiae mutants that produce urdamycin A. After expression of lanV in S. fradiae ΔurdM, which is a mutant that accumulates rabelomycin, urdamycinon B and urdamycin B were found to be produced by the strain. This result indicates that LanV is involved in the 6‐ketoreduction of the angucycline core, which preceeds a 5,6‐dehydration reaction. 9‐C‐D‐Olivosyltetrangulol was also produced by this strain; this demonstrates that LanV catalyses the aromatization of ring A of the angucycline structure. Coexpression of lanV and lanGT2 in S. fradiae AO, a mutant that lacks all four urdamycin glycosyltransferases, resulted in the production of tetrangulol and the glycoside landomycin H, both of which have an aromatic ring A. As glycosylated angucyclines were not observed after expression of lanGT2 in the absence of lanV, we conclude that LanGT2 needs an aromatized ring A for substrate recognition.
Reversible Sequential‐Binding Probe Receptor–Ligand Interactions in Single Cells
Authors: Schreiter Christoph , Gjoni Marinela , Hovius Ruud , Martinez Karen L. , Segura Jean‐Manuel , Vogel Horst 
Published: November 2005

AbstractWith the reversible sequential (ReSeq) binding assay,we present a novel approach for the ultrasensitive profiling of receptor function in single living cells. This assay is based on the repetitive application of fluorescent ligands that have fast association–dissociation kinetics. We chose the nicotinic‐acetylcholine receptor (nAChR) as a prototypical example and performed ReSeq equilibrium, kinetic, and competition‐binding assays using fluorescent derivatives of the antagonist α‐conotoxin GI (α‐CnTx). Thereby, we determined the binding constants of unlabeled α‐CnTx and d‐tubocurarine. The high selectivity of α‐CnTx for muscle‐type nAChR made it possible to observe specific binding even in the presence of other nAChR subtypes. Imaging of individual nAChRs and ligand‐binding cycles to single cells in microfluidic devices demonstrated the ultimate miniaturization and accuracy of ReSeq‐binding assays even at low receptor‐expression levels. We expect our approach to be of generic importance for functional screening of compounds or membrane receptors, and for the detailed characterization of rare primary cells.
Acyl Transfer in Clorobiocin Biosynthesis: Involvement of Several Proteins in the Transfer of the Pyrrole‐2‐carboxyl Moiety to the Deoxysugar
Authors: Freitag Anja , Wemakor Emmanuel , Li Shu‐Ming , Heide Lutz 
Published: November 2005

AbstractClorobiocin is an aminocoumarin antibiotic containing a pyrrole‐2‐carboxyl moiety, attached through an ester bond to a deoxysugar. The pyrrole moiety is important for the binding of the antibiotic to its biological target, gyrase. The complete biosynthetic gene cluster for clorobiocin has been cloned and sequenced from the natural producer, Streptomyces roseochromogenes DS 12.976. In this study, the genes cloN1 and cloN7 were deleted separately from a cosmid containing the complete clorobiocin cluster. The modified cosmids were introduced into the genome of the heterologous host Streptomyces coelicolor M512 by using the integration functions of the ΦC31 phage. While a heterologous producer strain harbouring the intact clorobiocin biosynthetic gene cluster accumulated clorobiocin, the cloN1‐ and cloN7‐defective integration mutants accumulated a clorobiocin derivative that lacked the pyrrole‐2‐carboxyl moiety, while also producing free pyrrole‐2‐carboxylic acid. The structures of these metabolites were confirmed by NMR and MS analysis. These results showed that CloN1 and CloN7, together with the previously investigated CloN2, are involved in the transfer of the pyrrole‐2‐carboxyl moiety to the deoxysugar of clorobiocin. A possible mechanism for the role of these three proteins in the acyl‐transfer process is suggested.
Use of Short Duplexes for the Analysis of the Sequence‐Dependent Cleavage of DNA by a Chemical Nuclease, a Manganese Porphyrin
Authors: Mourgues Sophie , Kupan Adam , Pratviel Geneviève , Meunier Bernard 
Published: November 2005

AbstractA manganese porphyrin, manganese(III)‐bis(aqua)‐meso‐tetrakis(4‐N‐methylpyridiniumyl)porphyrin, in the presence of KHSO5 is able to perform deoxyribose or guanine oxidation depending on its mode of interaction with DNA. These two reactions involve an oxygen‐atom transfer or an electron transfer, respectively. The oxidative reactivity of the manganese‐oxo porphyrin was compared on short oligonucleotide duplexes of different sequences. The major mechanism of DNA damage is due to deoxyribose hydroxylation at a site of strong interaction, an (A⋅T)3 sequence. Guanine oxidation by electron transfer was found not to be competitive with this major mechanism. It was found that a single intrastrand guanine was three orders of magnitude less reactive than an (A⋅T)3 sequence. The reactivity of a 5′‐GG sequence was found to be intermediate and was estimated to be two orders of magnitude less than that of an (A⋅T)3 site. Short oligonucleotide duplexes, as double‐stranded‐DNA models, proved to be convenient tools for the study of the comparative reactivity of this reagent toward different sequences of DNA. However, they showed a particular reactivity at their terminal base pairs (the “end effect”) that biased their modeling capacity for double‐helix‐DNA models.
Impact of a lead glass screen on scatter radiation to eyes and hands in interventional cardiologists
Authors: Maeder Micha , Brunner‐La Rocca Hans Peter , Wolber Thomas , Ammann Peter , Roelli Hans , Rohner Franziska , Rickli Hans 
Published: November 2005

AbstractThe objective of this study was to assess the impact of a transparent lead glass screen (TLGS) on scatter radiation to the eyes and the hands in interventional cardiologists and to compare the results to the recommended annual threshold values of 150 and 500 mSv, respectively. Local radiation doses to the left eye and the ring finger of the left hand of three operators (A, B, C) were assessed by thermoluminiscence dosimeters during 813 coronary angiographies (CAs), including 190 ad hoc percutaneous coronary interventions (PCIs) either with a TLGS placed between patient and operator [615 CAs including 138 ad hoc PCIs; dose‐area product (DAP) = 84.9 ± 71.3 Gy·cm2], or without (198 CAs including 52 PCIs; DAP = 85.7 ± 61.5 Gy·cm2). To determine the efficacy of the TLGS, average DAP‐normalized local doses were calculated. Using a TLGS, operator A, B, and C performed 259 (in 9 months), 211 (in 8 months), and 145 CAs (in 8 months) with TLGS and acquired cumulative eye lens doses of 5.5, 1.5, and 1.0 mSv corresponding to extrapolated annual doses of 7.3, 2.3, and 1.5 mSv. The cumulative finger doses were 9.6, 10.3, and 6.4 mSv, resulting in extrapolated annual doses of 12.8, 15.5, and 9.6 mSv. Compared to 139 (in 5 months), 36 (in 2 months), and 23 CAs (in 2 months) without TLGS, the use of a TLGS reduced the DAP‐normalized eye dose by a factor of 19 (with TLGS 0.153 vs. without TLGS 2.924 μSv/Gy·cm2), whereas only a weak effect on the dose to the hands was observed (with TLGS 0.504 vs. without TLGS 0.578 μSv/Gy·cm2). The consequent use of a TLGS efficiently reduces scatter radiation to the operator's eyes in daily practice, but has only minimal effects on the dose to the hands. © 2005 Wiley‐Liss, Inc.
Template Refolding by Use of an Antibody‐Coupled Affinity Column
Authors: Katoh S. , Kumada Y. , Maeshima N. 
Published: November 2005

AbstractTo improve the efficiency and throughput, the biointeraction between an antigen and antibody was used for refolding in a packed column, in which an antibody against carbonic anhydrase coupled on a gel support was used as a template ligand. A denatured solution of CAB was mixed with a refolding buffer in a mixing chamber, and was supplied to the antibody‐coupled column for refolding. Higher refolding efficiencies were obtained in the column than by the batch dilution method at relatively low concentrations of denaturant. By increasing the adsorption capacity of the column, the efficiency of refolding, as well as the throughput, could be increased.