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Yi Kang,1,2,* Han Ding,1,2,* Hengxing Zhou,1,2 Zhijian Wei,1,2 Lu Liu,1,2 Dayu Pan,1,2 Shiqing Feng1,2 1Department of Orthopaedics, Tianjin Medical University General Hospital, 2Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, People’s Republic of China *These authors contributed equally to this work Study design: A literature review of worldwide epidemiology of spinal cord injury (SCI). Objectives: To review the epidemiological indicators of SCI, such as incidence, prevalence, demographic characteristics, etiology, level and severity of injury, complications and mortality. Setting: The Department of Orthopaedics, Tianjin Medical University General Hospital, ­Heping District, Tianjin, People’s Republic of China. Methods: We searched articles published in PubMed, Medline, EMBASE and the Web of ­Science between January 1993 and June 2017 using the key words “spinal cord injury”, “­traumatic spinal cord injury”, “non-traumatic spinal cord injury” and “epidemiology”. The incidence, etiology, prevalence, patient demographics, level and severity of injury, complications and mortality were reviewed from the articles. Results: The epidemiology of SCI has changed. Motor vehicle accidents and falls have become the most common reasons of injury gradually. Incidence of SCI varies by regions or countries, and it has gradually increased with the expansion of human activities. The number of male patients were significantly more than female, the average age of patients with SCI had a tendency to increase gradually. The cervical level of spine was the most common part of injury; there were more number of patients with tetraplegia than patients with paraplegia. Electrolyte disturbances, pulmonary infections, urinary tract infections and bedsores were the four most common complications. Conclusion: We must have a greater understanding of epidemiology to implement more preventative measures. The epidemiology in different regions is of significant difference, which may be resulted from economic, science and technology, medical, geographical and even social conditions. Therefore, we must establish appropriate intervention measures according to the particularity of population. Keywords: spinal cord injury, etiology, incidence, patient demographics, complications

Aims: Deoxynivalenol (DON), namely vomitoxin, is one of the most prevalent fungal toxins in cereal crops worldwide. However, the underlying toxic mechanisms of DON remain largely unknown., Main Methods: DON exposure-caused changes in the murine plasma metabolome and gut microbiome were investigated by an LC-MS/MS-based nontargeted metabolomics approach and sequencing of 16S rRNA in fecal samples, respectively. Cellular models were then used to validate the findings from the metabolomics study., Key Findings: DON exposure increased intestinal barrier permeability evidenced by its-mediated decrease in colonic Claudin 5 and E-cadherin, as well as increases in colonic Ifn-γ, Cxcl9, Cxcl10, and Cxcr3. Furthermore, DON exposure resulted in a significant increase in murine plasma levels of deoxycholic acid (DCA). Also, DON exposure led to gut microbiota dysbiosis, which was associated with DON exposure-caused increase in plasma DCA. In addition, we found not only DON but also DCA dose-dependently caused a significant increase in the levels of IFN-γ, CXCL9, CXCL10, and/or CXCR3, as well as a significant decrease in the expression levels of Claudin 5 and/or E-cadherin in the human colonic epithelial cells (NCM460)., Significance: DON-mediated increase in DCA contributes to DON-caused intestinal injury. DCA may be a potential therapeutic target for DON enterotoxicity., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jun-Yan Liu reports financial support was provided by Chongqing Municipal Natural Science Foundation-Education Commission., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Human WASP and N-WASP are homologous proteins that require the binding of multiple regulators, including the acidic lipid PIP 2 and the small GTPase Cdc42, to relieve autoinhibition before they can stimulate the initiation of actin polymerization. Autoinhibition involves intramolecular binding of the C-terminal acidic and central motifs to an upstream basic region and GTPase binding domain. Little is known about how a single intrinsically disordered protein, WASP or N-WASP, binds multiple regulators to achieve full activation. Here we used molecular dynamics simulations to characterize the binding of WASP and N-WASP with PIP 2 and Cdc42. In the absence of Cdc42, both WASP and N-WASP strongly associate with PIP 2 -containing membranes, through their basic region and also possibly through a tail portion of the N-terminal WH1 domain. The basic region also participates in Cdc42 binding, especially for WASP; consequently Cdc42 binding significantly compromises the ability of the basic region in WASP, but not N-WASP, to bind PIP 2 . PIP 2 binding to the WASP basic region is restored only when Cdc42 is prenylated at the C-terminus and tethered to the membrane. This distinction in the activation of WASP and N-WASP may contribute to their different functional roles., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objective: Smoking affects sensory gating, as assessed by the event related potential P50, which is evoked by auditory stimuli and is considered to be involved in the pathophysiology of schizophrenia (SCZ). However, few studies have compared sensory gating and cognitive performance between smoking and non-smoking SCZ patients in the Chinese Han population., Methods: We recruited two groups of Chinese subjects: 128 male chronic SCZ patients and 76 male healthy controls, measuring cognition with the MATRICS Consensus Cognitive Battery (MCCB) and sensory gating with the P50 EEG components. Based on their smoking status, they were further divided into 4 subgroups: smoking SCZ patients, non-smoking SCZ patients, smoking healthy controls, and non-smoking healthy controls. We assessed psychopathological symptoms of the patients using the Positive and Negative Syndrome Scale (PANSS)., Results: Compared with healthy controls, SCZ patients had lower MCCB total score and scores of all 10 tests (all p < 0.05), while SCZ patients had higher S2 amplitudes and P50 ratios (both p < 0.05). When comparing smoking versus non-smoking SCZ patients, non-smokers had significantly better spatial span (p < 0.05). Furthermore, the S1 amplitude was negatively correlated with the Brief Visuospatial Memory Test (BVMT-R) in smoking patients (p < 0.05), while the S1 latency was negatively correlated with spatial span in non-smoking patients (p < 0.01)., Conclusions: Our finding shows a difference in the relationship between sensory gated P50 and cognition in smoking and non-smoking SCZ patients, suggesting that nicotine may improve cognitive and P50 deficits in SCZ patients., Competing Interests: Conflict of Interest Statement The authors declare that they have no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Bacterial cell division begins with the formation of the Z-ring via polymerization of FtsZ and the localization of Z-ring beneath the inner membrane through membrane anchors. In Mycobacterium tuberculosis (Mtb), SepF is one such membrane anchor, but our understanding of the underlying mechanism is very limited. Here we used molecular dynamics simulations to characterize how SepF itself, a water-soluble protein, tethers to acidic membranes that mimic the Mtb inner membrane. In addition to an amphipathic helix (residues 1-12) at the N-terminus, membrane binding also occurs through two stretches of positively charged residues (Arg27-Arg37 and Arg95-Arg107) in the long linker preceding the FtsZ-binding core domain (residues 128-218). The additional interactions via the disordered linker stabilize the membrane tethering of SepF, and keep the core domain of SepF and hence the attached Z-ring close to the membrane. The resulting membrane proximity of the Z-ring in turn enables its interactions with and thus recruitment of two membrane proteins, FtsW and CrgA, at the late stage of cell division., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background/ Aims: Early diagnosis of alcoholic liver cirrhosis (ALD) and coexisting ALD and hepatitis B virus-induced cirrhosis (ALD+HBV) is primordial for an optimal management of these conditions. However, the lack of specific noninvasive biomarkers coupled with the inaccuracy of self-reported alcohol consumption make the early diagnosis of these pathologies difficult. This study aimed to identify biomarkers to diagnose ALD and differentiate ALD+HBV from HBV., Methods: Proteomics mass spectrometry technique was used to identify specific proteins of ALD by contrasting serums of ALD to that of healthy subjects. The accuracy of the selected proteins in diagnosing ALD and discriminating ALD+HBV from HBV was assessed in two independent cohorts using the area under the receiver operator characteristic curve (AUROC)., Results: 452 cirrhotic and normal subjects were enrolled in this study. The proteomic results revealed that FcGBP and VCAM-1 were the highest overexpressed proteins while comparing ALD samples to the healthy cohort. The combination of these two biomarkers had an AUROC of 0.986 (P < 0.001, sensitivity: 97.2%, specificity: 100%) in identifying ALD from the healthy cohort, and AUROC of 0.781 (P < 0.001, sensitivity: 81.8%, specificity: 77.0%) in differentiating ALD+HBV from HBV. This combination was more accurate than the combination of AST/ALT, MCV and GGT (ALD vs healthy, AUROC = 0.898; ALD+HBV vs HBV, AUROC = 0.599). The discrimination performance of this combination was further validated in another independent cohort., Conclusion: FcGBP and VCAM-1 are two promising biomarkers in the diagnosis of ALD and in the differentiating of ALD+HBV from HBV subjects., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We present solid-state NMR measurements of β-strand secondary structure and inter-strand organization within a 150-kDa oligomeric aggregate of the 42-residue variant of the Alzheimer's amyloid-β peptide (Aβ(1-42)). We build upon our previous report of a β-strand spanned by residues 30-42, which arranges into an antiparallel β-sheet. New results presented here indicate that there is a second β-strand formed by residues 11-24. Contrary to expectations, NMR data indicate that this second β-strand is organized into a parallel β-sheet despite the co-existence of an antiparallel β-sheet in the same structure. In addition, the in-register parallel β-sheet commonly observed for amyloid fibril structure does not apply to residues 11-24 in the 150-kDa oligomer. Rather, we present evidence for an inter-strand registry shift of three residues that likely alternate in direction between adjacent molecules along the β-sheet. We corroborated this unexpected scheme for β-strand organization using multiple two-dimensional NMR and 13 C- 13 C dipolar recoupling experiments. Our findings indicate a previously unknown assembly pathway and inspire a suggestion as to why this aggregate does not grow to larger sizes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Paracrine factors such as glial cell line-derived neurotrophic factor (GDNF), which was originally derived from the supernatants of a rat glioma cell line, play pivotal roles in oocyte maturation and early embryo development in mammals, such as mice, rats, pigs, sheep, and even humans. However, whether GDNF facilitates in vitro oocyte maturation or early embryo development in bovines is not yet known. We show for the first time that GDNF and its receptor, GDNF family receptor alpha-1 (GFRA1), are presented in ovarian follicles at different stages as well as during oocyte maturation and early embryo development. Immunostaining results revealed the subcellular localizations of GDNF and GFRA1 in oocytes throughout follicle development, first in germinal vesicles and during blastocyst embryo stages. The ability of exogenously applied GDNF to promote oocyte maturation and early embryo development was evaluated in culture, where we found that an optimal concentration of 50 ng/mL promotes the maturation of cumulus-oocyte complexes and the nuclei of denuded oocytes as well as the development of embryos after IVF. To further investigate the potential mechanism by which GDNF promotes oocyte maturation, bovine oocytes were treated with morpholinos targeting Gfra1. The suppression of GFRA1 presence blocked endogenous and exogenous GDNF functions, indicating that the effects of GDNF that are essential and beneficial for bovine oocyte maturation and early embryo development occur through this receptor. Furthermore, we show that supplementation with GDNF improves the efficiency of bovine IVF embryo production., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: The metabolic effects of laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) in type 2 diabetes (T2D) patients who do not meet National Institutes of Health indications has not been well studied., Objectives: To compare the effectiveness of LSG and LRYGB in Chinese T2D patients with body mass index (BMI)<35 kg/m 2 ., Setting: University hospital, China., Methods: A nonrandomized cohort of patients who underwent LRYGB (n = 64) and LSG (n = 19) were followed up for 3 years and the outcomes (weight loss and remission of diabetes and other metabolic parameters) were compared. Univariate and multivariate analyses were applied to find associated parameters of T2D remission., Results: In total, 5 patients (6%) were lost to follow-up. No significant differences in mean percentage of excess weight loss and BMI were observed between the 2 groups at 2 years. At 3-year follow-up, the LRYGB group had significantly higher percentage of excess weight loss and lower BMI. The total (complete and partial) remission rate achieved with both bariatric procedures was 75.9% at 1 year and 56.4% at 3 years. Surgical safety, diabetes remission, and remission of other obesity-related co-morbidities were comparable between the 2 groups. Patients who achieved complete or partial remission had lower fasting plasma glucose, lower plasma glucose at 2 hours, lower glycated hemoglobin, and higher fasting C peptide than the other patients at baseline. High recurrence rates of hypertension and hyperuricemia were observed at 3 years postoperation., Conclusions: Both LSG and LRYGB are safe and effective bariatric procedures for T2D in this Chinese population with diabetes and BMI<35 kg/m 2 ., (Copyright © 2017 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Computational modeling is essential for structural characterization of biomolecular mechanisms across the broad spectrum of scales. Adequate understanding of biomolecular mechanisms inherently involves our ability to model them. Structural modeling of individual biomolecules and their interactions has been rapidly progressing. However, in terms of the broader picture, the focus is shifting toward larger systems, up to the level of a cell. Such modeling involves a more dynamic and realistic representation of the interactomes in vivo, in a crowded cellular environment, as well as membranes and membrane proteins, and other cellular components. Structural modeling of a cell complements computational approaches to cellular mechanisms based on differential equations, graph models, and other techniques to model biological networks, imaging data, etc. Structural modeling along with other computational and experimental approaches will provide a fundamental understanding of life at the molecular level and lead to important applications to biology and medicine. A cross section of diverse approaches presented in this review illustrates the developing shift from the structural modeling of individual molecules to that of cell biology. Studies in several related areas are covered: biological networks; automated construction of three-dimensional cell models using experimental data; modeling of protein complexes; prediction of non-specific and transient protein interactions; thermodynamic and kinetic effects of crowding; cellular membrane modeling; and modeling of chromosomes. The review presents an expert opinion on the current state-of-the-art in these various aspects of structural modeling in cellular biology, and the prospects of future developments in this emerging field., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Tanshinone IIA is one of the major constituents of Salvia miltiorrhiza Bunge known as Danshen. Recent reports have shown that Tanshinone IIA has neuroprotective effects against cerebral ischemia/reperfusion injury and traumatic injury of the spinal cord in rats. However, whether Tanshinone IIA has any neuroprotective effect in Parkinson's disease remains unknown. In this study, we evaluated whether Tanshinone IIA promotes the survival of nigrostriatal dopaminergic (DA) neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. MPTP induced degeneration of nigrostriatal DA neurons and microglial activation as visualized by tyrosine hydroxylase and CD11b immunoreactivity. The results of Western blot and immunohistochemistry showed upregulation of NADPH oxidase and iNOS in the MPTP-treated substantia nigra pars compacta. Treatment with Tanshinone IIA prevented degeneration of nigrostriatal DA neurons and increased the level of striatal dopamine content. This neuroprotection afforded by Tanshinone IIA was associated with the suppression of microglial activation and reduced expression of NADPH oxidase and iNOS. The present findings show that Tanshinone IIA may possess anti-inflammatory and anti-oxidative properties and may have therapeutic value in the treatment of Parkinson's disease., (Copyright © 2014 Elsevier B.V. All rights reserved.)

MgtR, a highly hydrophobic peptide expressed in Salmonella enterica serovar Typhimurium, inhibits growth in macrophages through binding to the membrane protein MgtC that has been identified as essential for replication in macrophages. While the Mycobacterium tuberculosis MgtC is highly homologous to its S. Typhi analogue, there does not appear to be an Mtb homologue for MgtR, raising significant pharmacological interest in this system. Here, solid-state NMR and EPR spectroscopy in lipid bilayer preparations were used to demonstrate the formation of a heterodimer between S. Typhi MgtR and the transmembrane helix 4 of Mtb MgtC. Based on the experimental restraints, a structural model of this heterodimer was developed using computational techniques. The result is that MgtR appears to be ideally situated in the membrane to influence the functionality of MgtC., (© 2013.)

Early detection of circulation tumor cells (CTCs) in breast cancer patients has great clinical relevance. Currently, immunomagnetic microparticles enriched assays require Fe3O4 inner cores, making it difficult to improve sensitivity. In this study, we prepared magnetic nanoparticles with carbon-coated pure iron (Fe@C) acted as the core, Conjugating with EpCAM monoclonal antibody for immunomagnetic nanoparticles(IMPs). IMPs were used in conjunction with immunocytochemistry (ICC) to develop a refined immunomagnetic nanoparticles enriched assay (IMPEA) for detection of circulating tumor cells (CTCs) in breast cancer patients. Compared with nested RT-PCR, this method achieved the same sensitivity, but with a significantly reduced false-positive rate. This method will help find hidden micrometastases, establish clinical stage, and guide individual treatment post-surgery, suggesting potentially significant value in the clinic., From the Clinical Editor: This team of investigators prepared magnetic nanoparticles with carbon-coated pure iron as core and conjugated them with EpCAM monoclonal antibody to form immunomagnetic nanoparticles for circulating tumor cell (CTC) detection. Compared with nested RT-PCR, this method achieved the same sensitivity, but with a significantly reduced false-positive rate, paving the way to the development of a tool that enables enhanced detection of micrometastases and post-surgical treatment monitoring., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The M2 protein from influenza A is a proton channel as a tetramer, with a single transmembrane helix from each monomer lining the pore. Val27 and Trp41 form gates at either end of the pore and His37 mediates the shuttling of protons across a central barrier between the N-terminal and C-terminal aqueous pore regions. Numerous structures of this transmembrane domain and of a longer construct that includes an amphipathic helix are now in the Protein Data Bank. Many structural differences are apparent from samples obtained in a variety of membrane mimetic environments. High-resolution structural results in lipid bilayers have provided novel insights into the functional mechanism of the unique HxxxW cluster in the M2 proton channel., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Pancreatic stem cells or progenitor cells posses the ability of directed differentiation into pancreatic β cells. However, these cells usually have limited proliferative capacity and finite lifespan in vitro. In the present study, Nestin-positive progenitor cells (NPPCs) from mouse pancreas that expressed the pancreatic stem cells or progenitor cell marker Nestin were isolated to obtain a sufficient number of differentiated pancreatic β cells. Tet-on system for SV40 large T-antigen expression in NPPCs was used to achieve reversible immortalization. The reversible immortal Nestin-positive progenitor cells (RINPPCs) can undergo at least 80 population doublings without senescence in vitro while maintaining their biological and genetic characteristics. RINPPCs can be efficiently induced to differentiate into insulin-producing cells that contain a combination of glucagon-like peptide-1 (GLP-1) and sodium butyrate. The results of the present study can be used to explore transplantation therapy of type I diabetes mellitus., (Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.)

The CAPRI (Critical Assessment of Predicted Interactions) and CASP (Critical Assessment of protein Structure Prediction) experiments have demonstrated the power of community-wide tests of methodology in assessing the current state of the art and spurring progress in the very challenging areas of protein docking and structure prediction. We sought to bring the power of community-wide experiments to bear on a very challenging protein design problem that provides a complementary but equally fundamental test of current understanding of protein-binding thermodynamics. We have generated a number of designed protein-protein interfaces with very favorable computed binding energies but which do not appear to be formed in experiments, suggesting that there may be important physical chemistry missing in the energy calculations. A total of 28 research groups took up the challenge of determining what is missing: we provided structures of 87 designed complexes and 120 naturally occurring complexes and asked participants to identify energetic contributions and/or structural features that distinguish between the two sets. The community found that electrostatics and solvation terms partially distinguish the designs from the natural complexes, largely due to the nonpolar character of the designed interactions. Beyond this polarity difference, the community found that the designed binding surfaces were, on average, structurally less embedded in the designed monomers, suggesting that backbone conformational rigidity at the designed surface is important for realization of the designed function. These results can be used to improve computational design strategies, but there is still much to be learned; for example, one designed complex, which does form in experiments, was classified by all metrics as a nonbinder., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Confinement and crowding are two major factors that can potentially impact protein folding in cellular environments. Theories based on considerations of excluded volumes predict disparate effects on protein folding stability for confinement and crowding: confinement can stabilize proteins by over 10k(B)T but crowding has a very modest effect on stability. On the other hand, confinement and crowding are both predicted to favor conformations of the unfolded state which are compact, and consequently may increase the folding rate. These predictions are largely borne out by experimental studies of protein folding under confined and crowded conditions in the test tube. Protein folding in cellular environments is further complicated by interactions with surrounding surfaces and other factors. Concerted theoretical modeling and test-tube and in vivo experiments promise to elucidate the complexity of protein folding in cellular environments.

The diphtheria toxin repressor contains an SH3-like domain that forms an intramolecular complex with a proline-rich (Pr) peptide segment and stabilizes the inactive state of the repressor. Upon activation of diphtheria toxin repressor (DtxR) by transition metals, this intramolecular complex must dissociate as the SH3 domain and Pr segment form different interactions in the active repressor. Here we investigate the dynamics of this intramolecular complex using backbone amide nuclear spin relaxation rates determined using NMR spectroscopy and molecular dynamics trajectories. The SH3 domain in the unbound and bound states showed typical dynamics in that the secondary structures were fairly ordered with high generalized order parameters and low effective correlation times, while residues in the loops connecting beta-strands exhibited reduced generalized order parameters and required additional motional terms to adequately model the relaxation rates. Residues forming the Pr segment exhibited low-order parameters with internal rotational correlation times on the order of 0.6 ns-1 ns. Further analysis showed that the SH3 domain was rich in millisecond time scale motions while the Pr segment exhibited motions on the 100 mus time scale. Molecular dynamics simulations indicated structural rearrangements that may contribute to the observed relaxation rates and, together with the observed relaxation rate data, suggested that the Pr segment exhibits a binding<-->unbinding equilibrium. The results here provide new insights into the nature of the intramolecular complex and provide a better understanding of the biological role of the SH3 domain in regulating DtxR activity.

An automated online gel permeation chromatography-gas chromatograph mass spectrometer (GPC-GC/MS) was developed for the rapid determination of residual pesticides in agricultural products. Pesticides were extracted from homogenized food samples with acetonitrile and decontaminated via the matrix solid-phase dispersion (MSPD) technique, using a primary secondary amine as sorbent prior to GPC-GC/MS analysis. A slightly modified preparation method and automated GPC step proved useful in minimizing matrix interference. To evaluate the performance of the system, 97 target pesticides were spiked at a concentration of 0.1mg/kg into a range of food types, including potato, cabbage, carrot, apple, orange, cucumber, and rice. A low flow rate of 0.1 mL/min in GPC resulted in a 40-fold reduction in solvent consumption compared with conventional GPC column applications. The combination of MSPD technique and GPC-GC/MS for the analysis of the 97 pesticides can be accomplished within 90 min. Most pesticides were recovered in the range of 70-120%, with relative standard deviation generally less than 10%. The results demonstrate that the method can be successfully applied with acceptable recoveries to a broad range of target pesticides within a diverse range of food types.

Objective: To evaluate the feasibility and effectiveness of autogenous coronoid process grafts for reconstruction of the mandibular condyle., Study Design: Two groups of 9 goats each were used. Each animal underwent unilateral total condyle and disk removal and was treated by grafting an autogeneous coronoid process. The animals in group A were sacrificed at 4, 12, and 24 weeks after surgical procedure, and their grafted coronoid processes were harvested for histological observation. All animals in group B received 3-dimensional CT scanning examination at different times and were sacrificed at 24 weeks after surgical procedure. The items of ramus height (RH), transverse dimension of the condyle (CT), and posteroanterior dimension of the condyle (CP) were measured for comparison with the operated and nonoperated sides., Results: Despite the differences in the measurements of RH, CT, and CP between the operated and nonoperated sides, the grafted coronoid process had a similar shape and histological structures to the normal condyle at 24 weeks after surgical procedure. The head of the neocondyle was covered by a cap of fibrous tissue, which might play the role of the articular disc., Conclusions: Under the mechanical stimuli of the temporomandibular joint site, the grafted coronoid process could gradually remodel to a neocondyle with functional shape and structure in goats. This animal study suggests that autogenous coronoid process could be considered as a new donor source for reconstruction of the mandibular condyle.

Background: The robotic surgical system overcomes many technological obstacles of conventional laparoscopic surgery, and possesses enormous clinical applied potential. The aim of this study was to compare the efficacy of Zeus robot-assisted laparoscopic cholecystectomy with conventional laparoscopic cholecystectomy., Methods: Forty patients undergoing elective cholecystectomy were randomly divided into two groups. Patients in group A (n=20) underwent Zeus robot-assisted laparoscopic cholecystectomy, and patients in group B (n=20) received conventional laparoscopic cholecystectomy. The parameters on operative field, operative time, the number of actions, the rate of operative errors and minimal trauma were evaluated and compared between the two groups., Results: The number of clearing camera (1.1+/-1.0 times) and the time of adjusting the operative field (2.2+/-0.7 minutes) in group A were significantly less than those (4.5+/-1.5 times) and (7.5+/-1.2 minutes) in group B. The number of dissection actions (337+/-86 times) and the rate of operative errors (10%) in group A were less than those (389+/-94 times), (25%) in group B. The total operation time (104.9+/-20.5 minutes) and setup time (29.5+/-9.8 minutes) in group A were significantly longer than those (78.6+/-17.1 minutes), (12.6+/-2.5 minutes) in group B. Blood loss and postoperative hospitalization were similar. No postoperative complications occurred in both groups, and open cholecystectomy was performed in each group., Conclusions: Zeus robot-assisted cholecystectomy inherits the benefits of minimally invasive surgery. The Zeus robotic surgical system is better than conventional laparoscopic technique in controlling the operative field and can be manipulated precisely and stably though it requires more operative time.

Environmental variables can exert significant influences on the folding stability of a protein, and elucidating these influences provides insight on the determinants of protein stability. Here, experimental data on the stability of FKBP12 are reported for the effects of three environmental variables: pH, salt, and macromolecular crowding. In the pH range of 5-9, contribution to the pH dependence of the unfolding free energy from residual charge-charge interactions in the unfolded state was found to be negligible. The negligible contribution was attributed to the lack of sequentially nearest neighboring charged residues around groups that titrate in the pH range. KCl lowered the stability of FKBP12 and the E31Q/D32N double mutant at small salt concentrations but raised stability after approximately 0.5 M salt. Such a turnover behavior was accounted for by the balance of two opposing types of protein-salt interactions: the Debye-Hückel type, modeling the response of the ions to protein charges, favors the unfolded state while the Kirkwood type, accounting for the disadvantage of the ions moving toward the low-dielectric protein cavity from the bulk solvent, disfavors the unfolded state. Ficoll 70 as a crowding agent was found to have a modest effect on protein stability, in qualitative agreement with a simple model suggesting that the folded and unfolded states are nearly equally adversely affected by macromolecular crowding. For any environmental variable, it is the balance of its effects on the folded and unfolded states that determines the outcome on the folding stability.

Circular versions of a large number of proteins have been designed by connecting the N and C termini via peptide linkers. A motivation for these designs is the assumed enhancement in folding stability, because backbone cyclization reduces the chain entropy of the unfolded state. Here, it is recognized that backbone cyclization also reduces the chain entropy of a flexible peptide linker in the folded state. Specifically, the end-to-end distance of the linker is restricted to fluctuations around the average displacement between the N and C termini of the folded protein. The balance of the chain-entropy reductions in the folded and unfolded states is used to predict the change in the unfolding free energy, deltadeltaG(cycl), by backbone cyclization. Predicted values of deltadeltaG(cycl) are in quantitative agreement with results of a careful study on cyclizing the 34 residue PIN1 WW domain by linkers with two to seen residues. The experimental results of an optimal linker length l=4 and a maximum stabilization of 1.7 kcal/mol are reproduced. Calculations of deltadeltaG(cycl) for a broad selection of circular proteins suggest that the stabilizing effect of backbone cyclization is modest, reflecting entropy reductions in both the unfolded and the folded states.

Protein and other antigens typically have a number of different epitopes. This presents an opportunity for designing high-affinity antibodies by connecting via a flexible peptide linker two antibody fragments recognizing non-overlapping epitopes on the same antigen. The same strategy was employed in natural and designed DNA-binding proteins. According to a previous theory, the linking enhances the antigen-binding affinity over those of the individual antibody fragments (with association constants K(A) and K(B)) by p(d(0))K(B) or p(d(0))K(A), where p(d(0))=(3/4pil(p)bL)(3/2)exp(-3d(0)(2)/4l(p)bL)(1-5l(p)/4bL+ cdots, three dots, centered ) is the probability density for the end-to-end vector of the flexible linker with L residues to have a distance d(0). The predicted affinity enhancement is found to be actually approached by a bi-specific antibody against hen egg lysozyme consisting of scFv fragments of D1.3 and HyHEL-10. The wide applicability of the theory is demonstrated by diverse examples of protein-protein interactions constrained by flexible linkers.

The electrostatic enhancement of the association rate of barnase and barstar is calculated using a transition-state theory like expression and atomic-detail modeling of the protein molecules. This expression predicts that the rate enhancement is simply the average Boltzmann factor in the region of configurational space where association occurs instantaneously in the diffusion-controlled limit. Based on experimental evidence, this "transition state" is defined by configurations in which, relative to the stereospecifically bound complex, the two proteins are shifted apart by approximately 8 A (so a layer of water can be accommodated in the interface) and the two binding surfaces are rotated away by 0 degrees to 3 degrees. The values of the average Boltzmann factor, calculated by solving the Poisson-Boltzmann equation, for the wild-type complex and 16 complexes with single mutations are found to correlate well with experimental results for the electrostatic rate enhancement. The predicted rate enhancement is found to be somewhat insensitive to the precise definition of the transition state, due to the long-range nature of electrostatic interactions. The experimental ionic strength dependence of the rate enhancement is also reasonably reproduced., (Copyright 1998 Academic Press Limited.)

A method is presented to account for conformational fluctuations of a protein in predicting the pK(a) values of its titrating groups. Conformations of the protein are generated by conventional molecular dynamics or Monte Carlo simulations, in which the protonations of the titrating groups are fixed. For each protein conformation, the electrostatic free energies required to add a proton charge to a titrating group while other groups are either unprotonated or protonated are calculated within a dielectric continuum model. These are used to determine the mean protonations of the titrating groups in the conformation at a series of pH values. The mean protonations are then used to determine the relative weight of the particular conformation with the titrating groups having all possible protonations. A conformationally averaged mean protonation for each titrating group is finally obtained by the weighted sum of the group's mean protonations in all the conformations. This method is applied to yeast iso-1-ferricytochrome c. The predicted pK(a) values are in general agreement with experimental results.