bluuebunny/crossref_metadata_2025 huggingface dataset:
Is the C-terminal insertional signal in Gram-negative bacterial outer membrane proteins species-specific or not?
Authors: Paramasivam Nagarajan , Habeck Michael , Linke Dirk
Published: September 2012

Background

In Gram-negative bacteria, the outer membrane is composed of an asymmetric lipid bilayer of phopspholipids and lipopolysaccharides, and the transmembrane proteins that reside in this membrane are almost exclusively β-barrel proteins. These proteins are inserted into the membrane by a highly conserved and essential machinery, the BAM complex. It recognizes its substrates, unfolded outer membrane proteins (OMPs), through a C-terminal motif that has been speculated to be species-specific, based on theoretical and experimental results from only two species,Escherichia coliandNeisseria meningitidis, where it was shown on the basis of individual sequences and motifs that OMPs from the one cannot easily be over expressed in the other, unless the C-terminal motif was adapted. In order to determine whether this species specificity is a general phenomenon, we undertook a large-scale bioinformatics study on all predicted OMPs from 437 fully sequenced proteobacterial strains.

Results

We were able to verify the incompatibility reported betweenEscherichia coliandNeisseria meningitidis, using clustering techniques based on the pairwise Hellinger distance between sequence spaces for the C-terminal motifs of individual organisms. We noticed that the amino acid position reported to be responsible for this incompatibility betweenEscherichia coliandNeisseria meningitidisdoes not play a major role for determining species specificity of OMP recognition by the BAM complex. Instead, we found that the signal is more diffuse, and that for most organism pairs, the difference between the signals is hard to detect. Notable exceptions are theNeisseriales, andHelicobacter spp. For both of these organism groups, we describe the specific sequence requirements that are at the basis of the observed difference.

Conclusions

Based on the finding that the differences between the recognition motifs of almost all organisms are small, we assume that heterologous overexpression of almost all OMPs should be feasible inE. coliand other Gram-negative bacterial model organisms. This is relevant especially for biotechnology applications, where recombinant OMPs are used e.g. for the development of vaccines. For the species in which the motif is significantly different, we identify the residues mainly responsible for this difference that can now be changed in heterologous expression experiments to yield functional proteins.
A Fur-like protein PerR regulates two oxidative stress response related operons dpr and metQIN in Streptococcus suis
Authors: Zhang Tengfei , Ding Yi , Li Tingting , Wan Yun , Li Wei , Chen Huanchun , Zhou Rui
Published: September 2012

Background

Metal ions are important micronutrients in cellular metabolism, but excess ions that cause toxic reactive oxygen species are harmful to cells. In bacteria, Fur family proteins such as Fur, Zur and PerR manage the iron and zinc uptake and oxidative stress responses, respectively. The single Fur-like protein (annotated as PerR) in Streptococcus suis has been demonstrated to be involved in zinc and iron uptake in previous studies, but the reports on oxidative stress response and gene regulation are limited.

Results

In the present study, the perR gene deletion mutant ΔperR was constructed in Streptococcus suis serotype 2 strain SC-19, and the mutant strain ΔperR exhibited less sensitivity to H2O2 stress compared to the wild-type. The dpr and metQIN were found to be upregulated in the ΔperR strain compared with SC-19. Electrophoretic mobility shift assays showed that the promoters of dpr and metQIN could be bound by the PerR protein. These results suggest that dpr and metQIN are members of the PerR regulon of S. suis. dpr encodes a Dps-like peroxide resistance protein, and the dpr knockout strains (Δdpr and ΔdprΔperR) were highly sensitive to H2O2. MetQIN is a methionine transporter, and the increased utilization of methionine in the ΔperR strain indirectly affected the peroxide resistance. Using a promoter–EGFP gene fusion reporting system, we found that the PerR regulon was induced by H2O2, and the induction was modulated by metal ions. Finally, we found that the pathogenicity of the perR mutant was attenuated and easily cleared by mice.

Conclusions

These data strongly suggest that the Fur-like protein PerR directly regulates dpr and metQIN and plays a crucial role in oxidative stress response in S. suis.
Facilitating knowledge transfer: decision support tools in environment and health
Authors: Liu Hai-Ying , Bartonova Alena , Neofytou Panagiotis , Yang Aileen , Kobernus Michael J , Negrenti Emanuele , Housiadas Christos
Published: September 2012

The HENVINET Health and Environment Network aimed to enhance the use of scientific knowledge in environmental health for policy making. One of the goals was to identify and evaluate Decision Support Tools (DST) in current use. Special attention was paid to four “priority” health issues: asthma and allergies, cancer, neurodevelopment disorders, and endocrine disruptors.

We identified a variety of tools that are used for decision making at various levels and by various stakeholders. We developed a common framework for information acquisition about DSTs, translated this to a database structure and collected the information in an online Metadata Base (MDB).

The primary product is an open access web-based MDB currently filled with 67 DSTs, accessible through the HENVINET networking portal http://www.henvinet.eu and http://henvinet.nilu.no. Quality assurance and control of the entries and evaluation of requirements to use the DSTs were also a focus of the work.

The HENVINET DST MDB is an open product that enables the public to get basic information about the DSTs, and to search the DSTs using pre-designed attributes or free text. Registered users are able to 1) review and comment on existing DSTs; 2) evaluate each DST’s functionalities, and 3) add new DSTs, or change the entry for their own DSTs.

Assessment of the available 67 DSTs showed: 1) more than 25% of the DSTs address only one pollution source; 2) 25% of the DSTs address only one environmental stressor; 3) almost 50% of the DSTs are only applied to one disease; 4) 41% of the DSTs can only be applied to one decision making area; 5) 60% of the DSTs’ results are used only by national authority and/or municipality/urban level administration; 6) almost half of the DSTs are used only by environmental professionals and researchers. This indicates that there is a need to develop DSTs covering an increasing number of pollution sources, environmental stressors and health end points, and considering links to other ‘Driving forces-Pressures-State-Exposure-Effects-Actions’ (DPSEEA) elements. Of interest to both researchers and decision makers should be the standardization of the way DSTs are described for easier access to the knowledge, and the identification of coverage gaps.
Double-donor complex in vertically coupled quantum dots in a threading magnetic field
Authors: Manjarres-García Ramón , Escorcia-Salas Gene Elizabeth , Manjarres-Torres Javier , Mikhailov Ilia D , Sierra-Ortega José
Published: September 2012

We consider a model of hydrogen-like artificial molecule formed by two vertically coupled quantum dots in the shape of axially symmetrical thin layers with on-axis single donor impurity in each of them and with the magnetic field directed along the symmetry axis. We present numerical results for energies of some low-lying levels as functions of the magnetic field applied along the symmetry axis for different quantum dot heights, radii, and separations between them. The evolution of the Aharonov-Bohm oscillations of the energy levels with the increase of the separation between dots is analyzed.
Relay on-off threshold for NDF protocol with distributed orthogonal space-time block codes
Authors: Jin Dong-Sup , Jin Xianglan , No Jong-Seon , Shin Dong-Joon
Published: September 2012

In this article, a relay on-off threshold (ROT) based on symbol error rate is derived for the cooperative communication networks with multiple antennas, where the non-orthogonal decode-and-forward (NDF) protocol with source antenna switching and linear combining decoding are used as the relaying protocol and decoding scheme, respectively. The optimal ROT for the cases using distributed orthogonal space-time block codes is derived for high signal to noise ratio (SNR) region and also a suboptimal ROT is provided for low SNR region. Finally, the diversity order of the NDF protocol using the relay on-off scheme with the proposed ROT is derived and its performance is verified through numerical analysis.
Medicinal use of fauna by a traditional community in the Brazilian Amazonia
Authors: Barros Flávio B , Varela Susana AM , Pereira Henrique M , Vicente Luís
Published: September 2012

Background

Zootherapy inventories are important as they contribute to the world documentation of the prevalence, importance and diversity of the medicinal use of animals in traditional human communities. The present study aims to contribute with a more valuable example of the zootherapy practices of a traditional community in the Brazilian Amazonia – the “Riozinho do Anfrísio” Extractive Reserve, in Northern Brazil.

Methods

We used the methods of participant observation and semi-structured interviews, applied to 25 informants. We employed the combined properties of two indices to measure the medicinal importance of each cited species to the studied community, as well as their versatility in the treatment of diseases: the well known Use Value (UV) and the Medicinal Applications Value (MAV) that we developed.

Results

We recorded 31 species of medicinal animals from six taxonomic categories, seven of which are new to science. The species are used for the treatment of 28 diseases and one species is used as an amulet against snakebites. The five species with the highest UV indices are the most popular and valued by the studied community. Their contrasting MAV indices indicate that they have different therapeutic properties: specific (used for the treatment of few diseases; low versatility) and all-purpose (several diseases; high versatility). Similarly, the most cited diseases were also those that could be treated with a larger number of animal species. Ten species are listed in the CITES appendices and 21 are present in the IUCN Red List. The knowledge about the medicinal use of the local fauna is distributed evenly among the different age groups of the informants.

Conclusions

This study shows that the local fauna represents an important medicinal resource for the inhabitants of the protected area. The combined use of the UV and MAV indices allowed identifying the species with the highest therapeutic potential. This type of information about a species may be of interest to pharmacological research, and is crucial to its conservation, since it helps signaling the species that may undergo higher hunting pressures. Data on zootherapy can also be of interesting to ecologists by contributing to indicators of local biodiversity richness.
PCR identification of culicoid biting midges (Diptera, Ceratopogonidae) of the Obsoletus complex including putative vectors of bluetongue and Schmallenberg viruses
Authors: Lehmann Kathrin , Werner Doreen , Hoffmann Bernd , Kampen Helge
Published: September 2012

Background

Biting midges of the Obsoletus species complex of the ceratopogonid genus Culicoides were assumed to be the major vectors of bluetongue virus (BTV) in northern and central Europe during the 2006 outbreak of bluetongue disease (BT). Most recently, field specimens of the same group of species have also been shown to be infected with the newly emerged Schmallenberg virus (SBV) in Europe. A reliable identification of the cryptic species of this group is fundamental for both understanding the epidemiology of the diseases and for targeted vector control. In the absence of classical morphological characters unambiguously identifying the species, DNA sequence-based tests have been established for the distinction of selected species in some parts of Europe. Since specificity and sensitivity of these tests have been shown to be in need of improvement, an alternative PCR assay targeting the mitochondrial cytochrome oxidase subunit I (COI) gene was developed for the identification of the three Obsoletus complex species endemic to Germany (C. obsoletus, C. scoticus, C. chiopterus) plus the isomorphic species C. dewulfi.

Methods

Biting midges of the genus Culicoides caught by UV light traps all over Germany were morphologically pre-identified to species or complex level. The COI region was amplified from their extracted DNA and sequenced. Final species assignment was done by sequence comparison to GenBank entries and to morphologically identified males. Species-specific consensus sequences were aligned and polymorphisms were utilized to design species-specific primers to PCR-identify specimens when combined with a universal primer.

Results

The newly developed multiplex PCR assay was successfully tested on genetically defined Obsoletus complex material as well as on morphologically pre-identified field material. The intended major advantage of the assay as compared to other PCR approaches, namely the production of only one single characteristic band for each species, could be realized with high specificity and sensitivity.

Conclusion

To elucidate the biological characteristics of potential vectors of disease agents, such as ecology, behaviour and vector competence, and the role of these haematophagous arthropods in the epidemiology of the diseases, simple, cost-effective and, most importantly, reliable identification techniques are necessary. The PCR assay presented will help to identify culicoid vector species and therefore add to bluetongue and Schmallenberg disease research including vector control and monitoring.
Bioluminescent imaging of Trypanosoma cruzi infection in Rhodnius prolixus
Authors: Henriques Cristina , Castro Daniele P , Gomes Leonardo HF , Garcia Eloi S , de Souza Wanderley
Published: September 2012

Background

Usually the analysis of the various developmental stages of Trypanosoma cruzi in the experimentally infected vertebrate and invertebrate hosts is based on the morphological observations of tissue fragments from animals and insects. The development of techniques that allow the imaging of animals infected with parasites expressing luciferase open up possibilities to follow the fate of bioluminescent parasites in infected vectors.

Methods

D-luciferin (60 μg) was injected into the hemocoel of the whole insect before bioluminescence acquisition. In dissected insects, the whole gut was incubated with D-luciferin in PBS (300 μg/ml) for ex vivo bioluminescence acquisition in the IVIS® Imaging System, Xenogen.

Results

Herein, we describe the results obtained with the luciferase gene integrated into the genome of the Dm28c clone of T. cruzi, and the use of these parasites to follow, in real time, the infection of the insect vector Rhodnius prolixus, by a non- invasive method. The insects were evaluated by in vivo bioluminescent imaging on the feeding day, and on the 7 th, 14 th, 21 st and 28 th days after feeding. To corroborate the bioluminescent imaging made in vivo, and investigate the digestive tract region, the insects were dissected. The bioluminescence emitted was proportional to the number of protozoans in regions of the gut. The same digestive tracts were also macerated to count the parasites in distinct morphological stages with an optical microscope, and for bioluminescence acquisition in a microplate using the IVIS® Imaging System. A positive correlation of parasite numbers and bioluminescence in the microplate was obtained.

Conclusions

This is the first report of bioluminescent imaging in Rhodnius prolixus infected with trypomastigotes of the Dm28c-luc stable strain, expressing firefly luciferase. In spite of the distribution limitations of the substrate (D-luciferin) in the insect body, longitudinal evaluation of infected insects by bioluminescent imaging is a valuable tool. Bioluminescent imaging of the digestive tract infected with Dm28c-luc is highly sensitive and accurate method to track the fate of the parasite in the vector, in the crop, intestine and rectum. This methodology is useful to gain a better understanding of the parasite – insect vector interactions.
RELATCH: relative optimality in metabolic networks explains robust metabolic and regulatory responses to perturbations
Authors: Kim Joonhoon , Reed Jennifer L
Published: September 2012

Predicting cellular responses to perturbations is an important task in systems biology. We report a new approach, RELATCH, which uses flux and gene expression data from a reference state to predict metabolic responses in a genetically or environmentally perturbed state. Using the concept of relative optimality, which considers relative flux changes from a reference state, we hypothesize a relative metabolic flux pattern is maintained from one state to another, and that cells adapt to perturbations using metabolic and regulatory reprogramming to preserve this relative flux pattern. This constraint-based approach will have broad utility where predictions of metabolic responses are needed.
Examination of ERα Signaling Pathways in Bone of Mutant Mouse Models Reveals the Importance of ERE-Dependent Signaling
Authors: Chokalingam Kumar , Roforth Matthew M. , Nicks Kristy M. , McGregor Ulrike , Fraser Daniel , Khosla Sundeep , Monroe David G.
Published: September 2012

The mechanisms of estrogen receptor (ER)-α activity can be categorized into those involving direct (classical) or indirect (nonclassical) DNA binding. Although various mouse models have demonstrated the importance of ERα in bone, the specific gene expression patterns affected by these modes of ERα action are unknown. In this report, the gene expression patterns of ERα-deficient (ERKO) mice and nonclassical ER knock-in (NERKI) mice, which can function only by nonclassical means, were analyzed. Three-month-old mice were ovariectomized and implanted with estrogen pellets for 1 month to normalize estrogen levels. Microarray analysis of flushed cortical bone revealed 28% (210 of 763) of the genes differentially expressed in ERKO mice were altered in NERKI mice, suggesting estrogen response element-dependent regulation of these genes in bone. Pathway analysis revealed alterations in genes involved in focal adhesion and extracellular matrix interactions. However, the majority of genes regulated in ERKO mice (72%) were unique (i.e. not altered in NERKI mice), suggesting these are regulated by nonclassical mechanisms. To further explore the pathways affected in ERKO mice, we performed focused quantitative PCR arrays for genes involved in various aspects of bone physiology. Genes involved in bone formation, senescence, apoptosis, and autophagy were significantly regulated. Overall, the majority of the genes regulated by ERα in bone are via nonclassical pathways. However, because NERKI mice display an osteoporotic phenotype, it can be deduced that the minority of the estrogen response element-dependent genes/pathways play critical roles in the regulation of bone physiology. These data demonstrate the importance of classical ERα signaling in regulating bone metabolism.
Interactions between ICAM-5 and β1 integrins regulate neuronal synapse formation
Authors: Ning Lin , Tian Li , Smirnov Sergei , Vihinen Helena , Llano Olaya , Vick Kyle , Davis Ronald L. , Rivera Claudio , Gahmberg Carl G.
Published: September 2012

Intercellular adhesion molecule-5 (ICAM-5) is a dendrite-specific adhesion molecule, which functions in both the immune and nervous systems. ICAM-5 is the only negative regulator that has been identified for maturation of dendritic spines so far. Shedding of the ICAM-5 ectodomain promotes spine maturation and enhances synaptic activity. However, the mechanism by which ICAM-5 regulates spine development remains poorly understood. In this study, we found that ablation of ICAM5 expression resulted in a significant increase in the formation of synaptic contacts and the frequency of miniature excitatory post-synaptic currents, an indicator of pre-synaptic release probability. Antibodies against ICAM-5 and β1 integrins altered spine maturation. Furthermore, we found that β1 integrins serve as binding partners for ICAM-5. β1 integrins were immunoprecipitated with ICAM-5 from mouse brain and the binding region in ICAM-5 was localized to the two first Ig domains. β1 integrins were juxtaposed to filopodia tips at the early stage of synaptic formation, but as synapses matured, β1 integrins covered the mushroom spines. Loss of β1 integrins from the pre-synaptic sites affected the morphology of the post-synaptic structures. ICAM-5 ectodomain cleavage decreased or increased when the interaction between ICAM-5 and β1 integrins was potentiated or weakened, respectively, using antibodies. These results suggest that the interaction between ICAM-5 and β1 integrins is important in formation of functional synapses.
Poc1A and Poc1B act together in human cells to ensure centriole integrity
Authors: Venoux Magali , Tait Xavier , Hames Rebecca S. , Straatman Kees R. , Woodland Hugh R. , Fry Andrew M.
Published: September 2012

Proteomic studies in unicellular eukaryotes identified a set of centriolar proteins that included proteome of centriole 1 (Poc1). Functional studies in these organisms implicated Poc1 in centriole duplication and length control, as well as ciliogenesis. Using isoform-specific antibodies and RNAi depletion, we have examined the function of the two related human proteins, Poc1A and Poc1B. We find that Poc1A and Poc1B each localize to centrioles and spindle poles, but do so independently and with different dynamics. However, although loss of one or other Poc1 protein does not obviously disrupt mitosis, depletion of both proteins leads to defects in spindle organization with the generation of unequal or monopolar spindles. Our data indicate that, once incorporated, a fraction of Poc1A and Poc1B remains stably associated with parental centrioles, but that depletion prevents incorporation into nascent centrioles. Nascent centrioles lacking both Poc1A and Poc1B exhibit loss of integrity and maturation, and fail to undergo duplication. Thus, when Poc1A and Poc1B are co-depleted, new centrosomes capable of maturation cannot assemble and unequal spindles result. Interestingly, Poc1B, but not Poc1A, is phosphorylated in mitosis, and depletion of Poc1B alone was sufficient to perturb cell proliferation. Hence, Poc1A and Poc1B play redundant, but essential, roles in generation of stable centrioles, but Poc1B may have additional independent functions during cell cycle progression.
Clathrin is not required for SNX-BAR-retromer-mediated carrier formation
Authors: McGough Ian J. , Cullen Peter J.
Published: September 2012

Clathrin has been implicated in retromer-mediated trafficking, but its precise function remains elusive. Given the importance of retromers for efficient endosomal sorting, we have sought to clarify the relationship between clathrin and the SNX-BAR retromer. We find that the retromer SNX-BARs do not interact directly or indirectly with clathrin. In addition, we observe that SNX-BAR-retromer tubules and carriers are not clathrin coated. Furthermore, perturbing clathrin function, by overexpressing a dominant-negative clathrin or through suppression of clathrin expression, has no detectable effect on the frequency of SNX-BAR-retromer tubulation. We propose that SNX-BAR-retromer-mediated membrane deformation and carrier formation does not require clathrin, and hence the role of clathrin in SNX-BAR-retromer function would appear to lie in pre-SNX-BAR-retromer cargo sorting.
Why Are Target Interest Rate Changes so Persistent?
Authors: Coibion Olivier , Gorodnichenko Yuriy
Published: September 2012

While the degree of policy inertia in central banks' reaction functions is a central ingredient in theoretical and empirical monetary economics, the source of the observed policy inertia in the United States is controversial, with tests of competing hypotheses, such as interest-smoothing and persistent-shocks, being inconclusive. This paper employs real time data; nested specifications with flexible time series structures; narratives; interest rate forecasts of the Fed, financial markets, and professional forecasters; and instrumental variables to discriminate between competing explanations of policy inertia. The evidence strongly favors the interest-smoothing explanation and thus can help resolve a key puzzle in monetary economics. (JEL C53, E43, E47, E52, E58)
AUF1/hnRNP D is a novel protein partner of the EBER1 noncoding RNA of Epstein-Barr virus
Authors: Lee Nara , Pimienta Genaro , Steitz Joan A.
Published: September 2012

Epstein-Barr virus (EBV)–infected cells express two noncoding RNAs called EBV-encoded RNA (EBER) 1 and EBER2. Despite their high abundance in the nucleus (about 106 copies), the molecular function of these noncoding RNAs has remained elusive. Here, we report that the insertion into EBER1 of an RNA aptamer that binds the bacteriophage MS2 coat protein allows the isolation of EBER1 and associated protein partners. By combining MS2-mediated selection with stable isotope labeling of amino acids in cell culture (SILAC) and analysis by mass spectrometry, we identified AUF1 (AU-rich element binding factor 1)/hnRNP D (heterogeneous nuclear ribonucleoprotein D) as an interacting protein of EBER1. AUF1 exists as four isoforms generated by alternative splicing and is best known for its role in destabilizing mRNAs upon binding to AU-rich elements (AREs) in their 3′ untranslated region (UTR). Using UV crosslinking, we demonstrate that predominantly the p40 isoform of AUF1 interacts with EBER1 in vivo. Electrophoretic mobility shift assays show that EBER1 can compete for the binding of the AUF1 p40 isoform to ARE-containing RNA. Given the high abundance of EBER1 in EBV-positive cells, EBER1 may disturb the normal homeostasis between AUF1 and ARE-containing mRNAs or compete with other AUF1-interacting targets in cells latently infected by EBV.
Understanding the Performance of the Long Chain and Sparse Designs in Process Flexibility
Authors: Simchi-Levi David , Wei Yehua
Published: September 2012

The long chain has been an important concept in the design of flexible processes. This design concept, as well as other sparse designs, have been applied by the automotive and other industries as a way to increase flexibility in order to better match available capacities with variable demands. Numerous empirical studies have validated the effectiveness of these designs. However, there is little theory that explains the effectiveness of the long chain, except when the system size is large, i.e., by applying an asymptotic analysis.

Our attempt in this paper is to develop a theory that explains the effectiveness of long chain designs for finite size systems. First, we uncover a fundamental property of long chains, supermodularity, that serves as an important building block in our analysis. This property is used to show that the marginal benefit, i.e., the increase in expected sales, increases as the long chain is constructed, and the largest benefit is always achieved when the chain is closed by adding the last arc to the system. Then, supermodularity is used to show that the performance of the long chain is characterized by the difference between the performances of two open chains. This characterization immediately leads to the optimality of the long chain among 2-flexibility designs. Finally, under independent and identically distributed (i.i.d.) demand, this characterization gives rise to three developments: (i) an effective algorithm to compute the performances of long chains using only matrix multiplications; (ii) a result that the gap between the fill rate of full flexibility and that of the long chain increases with system size, thus implying that the effectiveness of the long chain relative to full flexibility increases as the number of products decreases; (iii) a risk-pooling result implying that the fill rate of a long chain increases with the number of products, but this increase converges to zero exponentially fast.
Reliable Traffic Sensor Deployment Under Probabilistic Disruptions and Generalized Surveillance Effectiveness Measures
Authors: Li Xiaopeng , Ouyang Yanfeng
Published: September 2012

Sensor systems as critical components of a transportation network provide a variety of real-time traffic surveillance information for traffic management and control. The deployment of sensors significantly affects their overall surveillance effectiveness. This paper proposes a reliable sensor location model to optimize surveillance effectiveness when sensors are subject to site-dependent probabilistic failures, and a general effectiveness measure is proposed to encompass most existing measures needed for engineering practice (e.g., flow volume coverage, vehicle-mile coverage, and squared error reduction). The problem is first formulated into a compact mixed-integer program, and we develop a variety of solution algorithms (including a custom-designed Lagrangian relaxation algorithm) and analyze their properties. We also propose alternative formulations including a continuum approximation model for single corridor problems and reliable fixed-charge sensor location models. Numerical case studies are conducted to test the performance of the proposed algorithms and draw managerial insights on how different parameter settings (e.g., failure probability and spatial heterogeneity) affect overall surveillance effectiveness and the optimal sensor deployment.
Modification of the Resch procedure
Authors: Roberts V. I. , Komarasamy B. , Pandey R.
Published: September 2012

Controversy surrounds the management of displaced three- and four-part fractures of the proximal humerus. The percutaneous Resch technique of stabilisation involves minimal soft-tissue dissection and a reduced risk of stiffness and avascular necrosis. However, it requires a second operation to remove Kirschner wires and the humeral block. We describe a modification of this technique that dispenses with the need for this second operation and relies on a sequential pattern of screw placement. We report the outcome of 32 three- or four-part fractures of the proximal humerus treated in this way at a mean follow-up of 3.8 years (2 to 8)). There were 14 men and 18 women with a mean age of 56 years (28 to 83). At final follow-up the mean Oxford shoulder scores were 38 (31 to 44) and 39 (31 to 42), and the mean Constant scores were 79 (65 to 92) and 72 (70 to 80) for three- and four-part fractures, respectively. We further analysed the results in patients aged < 60 years with high-energy fractures and those aged ≥ 60 years with osteoporotic fractures. There were no cases of nonunion or avascular necrosis.

The results were good and comparable to those previously reported for the Resch technique and other means of fixation for proximal humeral fractures. We would recommend this modification of the technique for the treatment of displaced three-part and four-part fractures in patients both younger and older than 60 years of age.
Somatosensory evoked potential monitoring of peripheral nerves during external fixation for limb lengthening and correction of deformity in children
Authors: Makarov M. R. , Samchukov M. L. , Birch J. G. , Cherkashin A. M. , Sparagana S. P. , Delgado M. R.
Published: September 2012

We undertook a retrospective analysis of 306 procedures on 233 patients, with a mean age of 12 years (1 to 21), in order to evaluate the use of somatosensory evoked potential (SSEP) monitoring for the early detection of nerve compromise during external fixation procedures for limb lengthening and correction of deformity. Significant SSEP changes were identified during 58 procedures (19%). In 32 instances (10.5%) the changes were transient, and resolved once the surgical cause had been removed. The remaining 26 (8.5%) were analysed in two groups, depending on whether or not corrective action had been performed in response to critical changes in the SSEP recordings. In 16 cases in which no corrective action was taken, 13 (81.2%, 4.2% overall) developed a post-operative neurological deficit, six of which were permanent and seven temporary, persisting for five to 18 months. In the ten procedures in which corrective action was taken, four patients (40%, 1.3% overall) had a temporary (one to eight months) post-operative neuropathy and six had no deficit.

After appropriate intervention in response to SSEP changes, the incidence and severity of neurological deficits were significantly reduced, with no cases of permanent neuropathy. SSEP monitoring showed 100% sensitivity and 91% specificity for the detection of nerve injury during external fixation. It is an excellent diagnostic technique for identifying nerve lesions when they are still highly reversible.
The pathogenesis of degeneration of the intervertebral disc and emerging therapies in the management of back pain
Authors: Hughes S. P. F. , Freemont A. J. , Hukins D. W. L. , McGregor A. H. , Roberts S.
Published: September 2012

This article reviews the current knowledge of the intervertebral disc (IVD) and its association with low back pain (LBP). The normal IVD is a largely avascular and aneural structure with a high water content, its nutrients mainly diffusing through the end plates. IVD degeneration occurs when its cells die or become dysfunctional, notably in an acidic environment. In the process of degeneration, the IVD becomes dehydrated and vascularised, and there is an ingrowth of nerves. Although not universally the case, the altered physiology of the IVD is believed to precede or be associated with many clinical symptoms or conditions including low back and/or lower limb pain, paraesthesia, spinal stenosis and disc herniation.

New treatment options have been developed in recent years. These include biological therapies and novel surgical techniques (such as total disc replacement), although many of these are still in their experimental phase. Central to developing further methods of treatment is the need for effective ways in which to assess patients and measure their outcomes. However, significant difficulties remain and it is therefore an appropriate time to be further investigating the scientific basis of and treatment of LBP.
Management of peri-prosthetic fracture of the humerus with severe bone loss and loosening of the humeral component after total shoulder replacement
Authors: Sewell M. D. , Kang S. N. , Al-Hadithy N. , Higgs D. S. , Bayley I. , Falworth M. , Lambert S. M.
Published: September 2012

There is little information about the management of peri-prosthetic fracture of the humerus after total shoulder replacement (TSR). This is a retrospective review of 22 patients who underwent a revision of their original shoulder replacement for peri-prosthetic fracture of the humerus with bone loss and/or loose components. There were 20 women and two men with a mean age of 75 years (61 to 90) and a mean follow-up 42 months (12 to 91): 16 of these had undergone a previous revision TSR. Of the 22 patients, 12 were treated with a long-stemmed humeral component that bypassed the fracture. All their fractures united after a mean of 27 weeks (13 to 94). Eight patients underwent resection of the proximal humerus with endoprosthetic replacement to the level of the fracture. Two patients were managed with a clam-shell prosthesis that retained the original components. The mean Oxford shoulder score (OSS) of the original TSRs before peri-prosthetic fracture was 33 (14 to 48). The mean OSS after revision for fracture was 25 (9 to 31). Kaplan-Meier survival using re-intervention for any reason as the endpoint was 91% (95% confidence interval (CI) 68 to 98) and 60% (95% CI 30 to 80) at one and five years, respectively.

There were two revisions for dislocation of the humeral head, one open reduction for modular humeral component dissociation, one internal fixation for nonunion, one trimming of a prominent screw and one re-cementation for aseptic loosening complicated by infection, ultimately requiring excision arthroplasty. Two patients sustained nerve palsies.

Revision TSR after a peri-prosthetic humeral fracture associated with bone loss and/or loose components is a salvage procedure that can provide a stable platform for elbow and hand function. Good rates of union can be achieved using a stem that bypasses the fracture. There is a high rate of complications and function is not as good as with the original replacement.
Collagenase for Dupuytren’s disease of the thumb
Authors: Bendon C. L. , Giele H. P.
Published: September 2012

Injectable collagenase is an alternative to surgical treatment for Dupuytren’s disease. Previous studies have reported on the effectiveness of collagenase in finger contractures. This prospective study reports on the short-term safety and efficacy of collagenase treatment in five thumb and first web space Dupuytren’s contractures. The thumb and first web space contractures were treated with injectable collagenase in four consecutive patients (five hands) with experience of previous surgical digital fasciectomy. The thumb contracture was measured by angle and span in two planes of thumb extension and abduction before injection and after manipulation. Collagenase treatment resulted in release of the contracture with a mean increase in thumb to index angle from 23° (10° to 35°) to 56° (45° to 60°) in extension and from 30° (10° to 50°) to 58° (50° to 65°) in abduction and a mean increase in span from 1.9 cm (1 to 3.5) to 3.9 cm (3 to 5) in extension and from 2.4 cm (1.5 to 3.5) to 3.9 cm (3 to 4.5) in abduction. All patients reported an increased range of movement and function and described collagenase therapy as preferable to surgery. In the short-term collagenase is an effective, well-tolerated and safe alternative to surgery for Dupuytren’s disease of the thumb.
Hybrid versus total pedicle screw instrumentation in patients undergoing surgery for neuromuscular scoliosis
Authors: Mattila M. , Jalanko T. , Puisto V. , Pajulo O. , Helenius I. J.
Published: September 2012

We compared the clinical, radiological and quality-of-life outcomes between hybrid and total pedicle screw instrumentation in patients undergoing surgery for neuromuscular scoliosis. A matched comparison using prospectively collected data was undertaken. A total of 66 patients underwent posterior or anteroposterior correction and fusion with hybrid (n = 33, mean age at surgery 15.8 years (9.10 to 19.6)) or total pedicle screw instrumentation (n = 33, mean age 14.7 years (7.0 to 20.7)) with a minimum follow-up of two years. The major curve pre-operatively was a mean of 87° (sd 29, 25° to 141°) and 81° (sd 18, 47° to 116°) in the hybrid and total pedicle screw groups, respectively (p = 0.29) and at a minimum of two years it was 33° (sd 20; 2° to 87°) and 20° (sd 12; 1° to 55°), respectively (p = 0.0016). The mean correction of the major curve was 59% (41% to 88%) in the hybrid and 75% (43% to 99%) in the total pedicle screw groups at two-year follow-up (p = 0.0011). The mean operating time was 7.45 hours (sd 2.18) and 6.04 hours (sd 1.71) in the hybrid and total pedicle screw groups, respectively (p = 0.001), and the mean intra-operative blood loss was 3760 ml (sd 2790) and 1785 ml (sd 1110), respectively (p = 0.001).

Total pedicle screw instrumentation provided shorter operating times, less blood loss and better correction of the major curve compared with hybrid constructs in patients undergoing surgery for neuromuscular scoliosis.
The radiological assessment of total and unicompartmental knee replacements
Authors: Sarmah S. S. , Patel S. , Hossain F. S. , Haddad F. S.
Published: September 2012

Radiological assessment of total and unicompartmental knee replacement remains an essential part of routine care and follow-up. Appreciation of the various measurements that can be identified radiologically is important. It is likely that routine plain radiographs will continue to be used, although there has been a trend towards using newer technologies such as CT, especially in a failing knee, where it provides more detailed information, albeit with a higher radiation exposure.

The purpose of this paper is to outline the radiological parameters used to evaluate knee replacements, describe how these are measured or classified, and review the current literature to determine their efficacy where possible.
Gastric perforation in an adult male following nasogastric intubation
Authors: Daliya P , White TJ , Makhdoomi KR
Published: September 2012

Introduction

Spontaneous gastric perforation is a well known surgical emergency which carries significant mortality and morbidity. Well documented causes in adults include peptic ulcer disease, drugs such as non-steroidal and gastric malignancy. Iatrogenic causes still remain relatively rare. We report an interesting case of an acutely unwell young man who developed gastric perforation secondary to nasogastric intubation.

Case Report

A 32 year old man initially treated for gastroenteritis underwent laparotomy for acute intra-abdominal bleeding. This was found to be secondary to a ruptured left hepatic artery aneurysm which was subsequently embolised. Patient had multiple laparotomies, a nasogastric tube inserted at the second laparotomy was later found to be the cause of gastric perforation. On further investigation the patient’s multiple aneurysms were histologically confirmed to be secondary to fibromuscular dysplasia (FMD).

Conclusion

We present here a case of gastric perforation from a nasogastric tube in an adult male and discussed its relevance to the diagnosis of FMD. This case highlights the importance of having a high index of suspicion for this complication when managing patients with severe abdominal sepsis.
An international survey of opinion regarding investigation of possible appendicitis and laparoscopic management of a macroscopically normal appendix
Authors: Jaunoo SS , Hale AL , Masters JPM , Jaunoo SR
Published: September 2012

INTRODUCTION

The use of imaging and laparoscopy in patients with right iliac fossa pain as tools to make or exclude a diagnosis of appendicitis is at the discretion of the clinician. We sought to establish a consensus of opinion on this matter by surveying professional bodies for laparoscopic surgery in France, Italy and the US.

METHODS

A survey was sent to members of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), as well as the French Society for Endoscopic Surgery (SFCE) and the Italian Society for Endoscopic Surgery (SICE). The survey asked about management of both male and female patients presenting with right iliac fossa pain and what operative strategy the respondents would pursue should they find a macroscopically normal appendix at laparoscopy.

RESULTS

A total of 364 responses were returned from the three groups. The responses from SAGES showed computed tomography to be the preferred modality for investigating patients with right iliac fossa pain, irrespective of sex. Both SFCE and SICE preferred the use of diagnostic laparoscopy, especially in the female patient group. The majority of all respondents stated that they would remove a macroscopically normal appendix at laparoscopy.

CONCLUSIONS

Laparoscopy remains a potent tool in the management of appendicitis. However, the dilemma of when to remove a macroscopically normal appendix remains. Our study shows that removal of the appendix in this instance would be supported by an international consensus.
Reliability of radiographic measurements of knee motion following knee arthroplasty for use in a virtual knee clinic
Authors: Phillips A , Goubran A , Naim S , Searle D , Mandalia V , Toms A
Published: September 2012

INTRODUCTION

We sought to validate radiographic measurements of range of motion of the knee after arthroplasty as part of a new system of virtual clinics.

METHODS

The range of motion of 52 knees in 45 patients was obtained by 2 clinicians using standardised techniques and goniometers. Inter-rater reliability and intraclass correlation coefficients (ICCs) were calculated. Radiographs of these patients’ knees in full active flexion and extension were also used to calculate intra and inter-rater reliability compared with clinical measurements using four different methods for plotting angles on the radiographs.

RESULTS

The ICC for inter-rater reliability using the goniometer was very high. The ICC was 0.91 in extension and 0.85 in flexion while repeatability was 8.49° (-8.03–8.99°) in extension and 5.23° (-4.54–5.74°) in flexion. The best ICC for radiographic measurement in extension was 0.86, indicating ‘near perfect’ agreement, and repeatability was 5.43° (-4.04–6.12°). The best ICC in flexion was 0.95 and repeatability was 5.82° (-3.38–6.55°). The ICC for intrarater reliability was 0.98 for extension and 0.99 for flexion on radiographic measurements.

CONCLUSIONS

Validating the use of radiographs to reliably measure range of motion following knee arthroplasty has allowed us to set up a ‘virtual knee clinic’. Combining validated questionnaires and radiographic measurement of range of motion, we aim to maintain high quality patient surveillance following knee arthroplasty, reduce our ratio for new to follow-up patients in line with Department of Health guidelines and improve patient satisfaction through reduced travel to hospital outpatients.
Buruli ulcer in a nine-month-old boy
Authors: Tsukagoshi S , Dehn TCB
Published: September 2012

The diagnosis of Buruli ulcer should be considered in all painless undermined ulcers in the tropics. The diagnosis and treatment are a challenge in rural settings despite the well established tuberculosis programmes. Immediate commencement on rifampicin and streptomycin is essential to halt the progression of disease and to, hopefully, reverse it. Surgery is indicated in those with complex ulcers or with complications. We report the case of a nine-month-old boy presenting to visiting British surgeons in a district hospital in Uganda with multiple ulcers to the right forearm.
Influencing policy to promote excellence in dentistry
Authors: Ferrari Gaynor
Published: September 2012

The faculty of general dental Practice (UK) (FGDP(UK)) works behind the scenes and on the front line to influence policy and promote good practice, as well as the 'day job' of promoting excellence in dentistry, setting standards and delivering education.
Access to surgery: a geriatrician's perspective
Authors: Dhesi Jugdeep
Published: September 2012

Older people are less likely to have surgery than younger people. This is true even for conditions more prevalent in the older population. given that older surgical patients have higher rates of post-operative complications, longer lengths of stay and higher mortality than younger patients, these findings are not particularly surprising.
CCrISP® roll-out to continue in Malaysia
Authors: Tavares Sandra
Published: September 2012

On 13 June the RCS hosted a visit from Professor Yip Cheng Har, President of the College of Surgeons of the Academy of Medicine of Malaysia. Professor Yip is a breast surgeon and Head of the Breast Surgery unit at the university of Malaya Medical Centre, Kuala Lumpur. She has published numerous articles in peer-reviewed journals and is currently involved in various research projects in the area of breast cancer.