Finite Element Analysis of Postoperative Stability of Transverse Scaphoid Waist Fracture.

Background and Purpose: Scaphoid waist fractures are often stabilised with compression screws, Kirschner wires (K-wires), or a combination of both. While clinical and bio-mechanical studies evaluating their utility are available, the ideal configuration of implant that would provide adequate stability to permit early use of the hand is debatable. We examined configurations of a single screw, one screw along with a K-wire, and two K-wires used for a transverse scaphoid waist fracture fixation aiming to assess the stability provided by each in the immediate postoperative period. Methods: Computer-aided design (CAD) models of the scaphoid, K-wire, and headless compression screw were created. A transverse fracture was created at the scaphoid waist, and the CAD models of the screw and K-wire were used to fix the fracture in different configurations in a distal to proximal direction. Finite Element Analysis (FEA) was used to examine the strength of configurations when they were subjected to compression and distraction forces. The total maximum deformation (TDef) and factor of safety (FoS) for each configuration were calculated and used as indirect indicators of postoperative stability. Results: When a single screw was used, the configurations with the screw directed posteriorly from either centre or anterior had the best combined TDef and FoS values. For one screw and one K-wire, the configuration with screw and K-wire parallel to each other with the screw located along the long axis in the AP projection and anterior to the K-wire in the lateral projection had the best combined TDef and FoS values. When using two K-wires, configurations with the two wires diverging proximally on the lateral projection had the best combined TDef and FoS values. Conclusions: When fixing a transverse scaphoid waist fracture with a single screw, the screw directed posteriorly from either the centre or anterior aspect of the distal pole has the best stability, a parallel configuration has the best stability when fixing it using a screw and a K-wire, and divergent configuration has the best stability when fixing it with two K-wires only.

Mechanism of scaphoid waist fracture: finite element analysis.

The mechanism of scaphoid waist fracture is not completely understood. We used finite element analysis to study the formation of scaphoid waist fractures. Clinical computed tomography scans of 12 wrists were used to create models for finite element analysis. The points of application of load were at different sites along the scaphotrapeziotrapezoid joint distally, and the scaphoid fossa plus the area underlying the radioscaphocapitate ligament was regarded as the fixed proximal support. A fracture was produced at the scaphoid waist in all cases. The location of failure of bone at its anterior or dorsal cortex, either in tension or in compression, was determined by the site of application of the load. The anterior cortex failed in compression when the point of impact was located along the trapezium facet or the entire distal pole, whereas it failed in tension when the point of impact was along the trapezoid facet.

Activity-Based Protein Profiling of Intraoperative Serine Hydrolase Activities during Cardiac Surgery.

The processes involved in the initiation of acute kidney injury (AKI) following cardiopulmonary bypass (CPB) are thought to occur during the intraoperative period. Such a rapid development might indicate that some of the inductive events are not dependent on de novo protein synthesis, raising the possibility that changes in activities of pre-existing enzymes could contribute to the development of AKI. Activity-based protein profiling (ABPP) was used to compare the serine hydrolase enzyme activities present in the urines of CPB patients who subsequently developed AKI versus those who did not (non-AKI) during the intra- and immediate postoperative periods. Sequential urines collected from a nested case-control cohort of AKI and non-AKI patients were reacted with a serine hydrolase activity probe, fluorophosphonate-TAMRA, and separated by SDS-PAGE. The patterns and levels of probe-labeled proteins in the two groups were initially comparable. However, within 1 h of CPB there were significant pattern changes in the AKI group. Affinity purification and mass spectrometry-based analysis of probe-labeled enzymes in AKI urines at 1 h CPB and arrival to the intensive care unit (ICU) identified 28 enzymes. Quantitative analysis of the activity of one of the identified enzymes, kallikrein-1, revealed some trends suggesting differences in the levels and temporal patterns of enzyme activity between a subset of patients who developed AKI and those who did not. A comparative analysis of affinity-purified probe reacted urinary proteins from these patient groups during the intraoperative period suggested the presence of both shared and unique enzyme patterns. These results indicate that there are intraoperative changes in the levels and types of serine hydrolase activities in patients who subsequently develop AKI. However, the role of these activity differences in the development of AKI remains to be determined.

A proteomic evaluation of urinary changes associated with cardiopulmonary bypass.

BACKGROUND: The urinary proteome of patients undergoing cardiopulmonary bypass (CPB) may provide important insights into systemic and renal changes associated with the procedure. Such information may ultimately provide a basis to differentiate changes or properties associated with the development of acute kidney injury. While mass spectrometry (MS) analysis offers the potential for in-depth compositional analysis it is often limited in coverage and relative quantitation capacity. The aim of this study was to develop a process flow for the preparation and comparison of the intraoperative urinary proteome. METHODS: Urines were collected from patients at the start of CPB and 1-h into CPB. Pooled samples (n = 5) from each time point were processed using a modified Filter Assisted Sample Preparation protocol. The resulting peptides were analyzed by 2D-LC-MS/MS and by 1D-LC-MS/MS SWATH (Sequential Window acquisition of All Theoretical fragment ion spectra). RESULTS: The 2D-LC-MS/MS analysis identified 1324 proteins in the two pools, of which 744 were quantifiable. The SWATH approach provided quantitation for 730 proteins, 552 of which overlapped with the common population from the 2D-IDA results. Intensity correlation filtering between the two methods gave 475 proteins for biological interpretation. Proteins displaying greater than threefold changes (>log2 1.59) at 1-hour CPB relative to the initiation of CPB (26 down-regulated and 22 up-regulated) were selected for further analysis. Up-regulated proteins were enriched in GO terms related to humoral immune response, predominantly innate immunity (C4b, lactotransferrin, protein S100-A8, cathelicidin, myeloperoxidase) and extracellular matrix reorganization (e.g. MMP-9). CONCLUSIONS: This study describes a scheme for processing urine from patients undergoing CPB for mass spectrometry-based analysis. The introduction of SWATH into the workflow offers a sample and instrument sparing approach to obtaining consistent in-depth sample analysis. The design of the methodology is such that it can be readily applied to large numbers of clinical samples with the potential for automation. The results also suggest that activation of the innate immune responses occur during cardiac bypass surgery.

Comparative evaluation of pressure generated on a simulated maxillary oral analog by impression materials in custom trays of different spacer designs: An in vitro study.

INTRODUCTION: Literature reveals that masticatory load on denture bearing tissues through complete dentures should be maximum on primary stress bearing areas and least on relief area in accordance with the histology of underlying tissues. A study to validate the existing beliefs was planned to compare the pressure on mucosa using selective pressure technique and minimal pressure technique, with the incorporation of two different impression materials utilizing the pressure sensors during secondary impression procedure. MATERIALS AND METHODS: The study was performed using a maxillary analog. Three pressure sensors were imbedded in the oral analog, one in the mid palatine area and the other two in the right and left ridge crest. Custom trays of two different configurations were fabricated. The two impression materials tested were light body and zinc oxide eugenol. A total of 40 impressions were made. A constant weight of 1 kg was placed, and the pressure was recorded as initial and end pressures. RESULTS: A significant difference in the pressure produced using different impression materials was found (P < 0.001). Light body vinyl polysiloxane produced significantly lesser pressure than zinc oxide eugenol impression materials. The presence of relief did affect the magnitude of pressure at various locations. CONCLUSION: All impression materials produced pressure during maxillary edentulous impression making. Tray modification is an important factor in changing the amount of pressure produced. The impression materials used also had a significant role to play on the pressures acting on the tissues during impression procedure. CLINICAL IMPLICATION: Light body VPS impression material may be recommended to achieve minimal pressure on the denture bearing tissues in both selective as well as minimal pressure techniques.

Development of an SRM method for absolute quantitation of MYDGF/C19orf10 protein.

PURPOSE: To develop a MS-based selected reaction monitoring (SRM) assay for quantitation of myeloid-derived growth factor (MYDGF) formerly chromosome 19 open reading frame (C19orf10). EXPERIMENTAL DESIGN: Candidate reporter peptides were identified in digests of recombinant MYDGF. Isotopically labeled forms of these reporter peptides were employed as internal standards for assay development. Two reference peptides were selected SYLYFQTFFK and GAEIEYAMAYSK with respective LOQ of 42 and 380 attomole per injection. RESULTS: Application of the assay to human serum and synovial fluid determined that the assay sensitivity was reduced and quantitation was not achievable. However, the partial depletion of albumin and immunoglobulin from synovial fluids provided estimates of 300-650 femtomoles per injection (0.7-1.6 nanomolar (nM) fluid concentrations) in three of the six samples analyzed. CONCLUSIONS AND CLINICAL RELEVANCE: A validated sensitive assay for the quantitation of MYDGF in biological fluids was developed. However, the endogenous levels of MYDGF in such fluids are at or below the current levels of quantitation. The levels of MYDGF are lower than those previously reported using an ELISA. The current results suggest that additional steps may be required to remove high abundance proteins or to enrich MYDGF for SRM-based quantitation.

Relationship of the lingual frenum to the mandibular central incisors.

CLINICAL IMPLICATION: The purpose of this study is to record the vertical distance between anterior attachment of lingual frenum and incisal edge of mandibular central incisors in dentulous subjects and then determine the mean vertical distance and to suggest guidelines for positioning of mandibular central incisors in complete dentures. METHOD: In this study, 150 dentulous subjects (75 males and 75 females) were chosen based on predecided inclusion criteria. A mandibular cast was obtained from irreversible hydrocolloid impression in modified stock trays for each subject. All subjects were instructed to elevate the tongue while the impressions were made. The vertical distance between the anterior attachment of the lingual frenum and incisal edges of mandibular central incisors was measured on the casts and then the values were statistically analyzed. RESULT: The distance between anterior attachment of lingual frenum (AALF) mesioincisal edge of mandibular central incisor (CI) in male, female and total (male + female) subjects was measured. In males it ranged from 7.3 to 8.9 mm with mean (±SD) 8.29 ± 0.36 mm while in females it ranged from 7.1 to 9.0 mm with mean (±SD) 8.21 ± 0.38 mm. CONCLUSION: It is believed that the application of this anatomic relation can provide a reliable point for arranging and checking the position of the mandibular central incisors for complete dentures in patients with class I ridge relationship.

Comparative evaluation of retentive properties of acid etched resin bonded fixed partial dentures.

BACKGROUND: Little consensus exist in suitable tooth preparation design and alloy pre-treatment methods for improving the retention of resin bonded fixed partial dentures (RBFPDs). METHODS: An in-vitro experiment was done with four designs. Group A: standard form, B: wings and proximal slices, C: wings, proximal slice and grooves, D: wings, proximal slice, grooves and occlusal coverage. Alloys were subjected to pre-treatment procedures like Group I: control, II: sand blasting, III: electro etching, IV: tin plating. Debonding forces of the castings were recorded in a universal testing machine and results were analyzed by student's 't' test. RESULTS: Group B, C and D showed higher debonding forces compared to A. However, there were no significant differences in mean force values among Groups B, C and D. Group II, III and IV with different alloy pre-treatment methods demonstrated higher values against control. Inter group variations among Group II, III and IV were not significant. CONCLUSION: Tooth preparation with adequate surface extensions and pre-treatment procedures of casting alloys are two parameters that play important role in determining the retentive features of RBFPDs. Different types of tooth preparation designs and alloy pre-treatment methods exert almost similar influence in increasing the retention of acid etched RBFPDs.

Systematic review of carcinoma arising in pharyngeal diverticula: a 112-year analysis.

BACKGROUND: Carcinoma is a rare complication of pharyngeal diverticula. There is a paucity of information about its incidence, presentation, management, and treatment outcomes. A systematic review and analysis of all reported cases has been carried out. METHODS: A comprehensive literature search for pharyngeal diverticula carcinoma was performed from 1896 to 2008. Descriptive analyses were carried out by analyzing the absolute and relative frequencies. Comparison of groups was illustrated with Kaplan-Meier curves and tested statistically using the log-rank test. A cohort of 56 patients with benign pharyngeal diverticula was selected for comparison with the accumulated cohort of pharyngeal diverticula carcinoma, and a Fisher's exact test was carried out on the extracted clinical characteristics of this cohort to evaluate for differences between benign and malignant pharyngeal diverticula. RESULTS: Forty-three articles reporting 60 cases satisfied the inclusion criteria. The mean age at presentation was 68.8 years (SD = 9.8 years). Five-year cancer-specific survival (CSS) rates for patients who underwent excision alone, excision + postoperative radiotherapy (PORT), and radiotherapy alone were 0.74 versus 0.63 versus 0.0, respectively (p = .39). Five-year CSS rates of patients <65 versus ≥65 years were 0.43 versus 0.78, respectively (p = .046). CONCLUSION: Irregular symptoms in benign diverticula should raise suspicion of malignancy. Management consists of surgical excision ± PORT. © 2014 Wiley Periodicals, Inc. Head Neck 36: 1368-1375, 2014.

Comparative evaluation of fracture resistance of various post systems using different luting agents under tangential loading.

OBJECTIVE: The purpose of this in vitro study was to evaluate the fracture resistance of various post system using different luting agents under tangential loading after wet thermocycling. MATERIAL & METHODS: Seventy freshly extracted maxillary central incisors were endodontically treated and post-spaces were prepared to receive different post system. They were assigned to 7 groups. Composite resin was used as core material in all the groups. Three type of post system: prefabricated post system (ParaPost(®) XP™), fibre post (ParaPost(®) fiber Lux™), cast nickel-chromium alloy post and two type of luting cements dual cure resin cement (ParaCem(®), Whaledent) and glass ionomer cement (Fuji I, GC) were used. The specimens were thermocycled and subjected to tangential loading at a crosshead speed of 1.5 mm/min. The failure loads were recorded and data were statistically analyzed with one-way ANOVA (p < 0.05) and Student's t tests (p < 0.001). RESULTS: Significant differences of fracture resistance were detected among groups (p < 0.001). The greatest number of repairable fracture mode was recorded in fibre posts and resin cement system. CONCLUSIONS: Within the limitations of this in vitro study, it can be stated that fibre posts can be recommended as a better alternative to the cast post and cores and prefabricated metallic posts in the anterior region and resin cement might give additional fracture resistance when used for post and crown cementation.

Comparative evaluation of vertical dimension at rest before extraction, after extraction and after rehabilitation with complete denture - A Cephalometric study.

INTRODUCTION: The determination of physiologic rest position of the mandible to the maxillae is of paramount importance in almost all fields of dentistry. The stability of vertical dimension at rest has been controversial if the rest position of mandible remains constant throughout life or not. Despite of several studies on the rest position of the mandible and facial vertical dimension, certain fundamental disagreements remain unresolved. The present study aims to compare the vertical dimension at rest, before and after extraction and after rehabilitation with complete denture. MATERIAL & METHODS: This study was conducted in a total of ten randomly selected patients, who had some natural teeth present with one or more opposing posterior teeth with vertical occlusal stops but were advised for extraction because of poor prognosis. Digital lateral cephalograms were done and measurements recorded at three stages: prior to extraction of remaining natural teeth, post extraction and after complete denture rehabilitation. RESULTS: Vertical dimension at rest was found to be greatest in post rehabilitation followed by pre-extraction than post extraction state. The differences in changes were found to be statistically significant. CONCLUSION: Vertical dimension at rest shows a decrease following extraction of natural teeth, the occlusal stops, and an increase on rehabilitation. It can be stated that vertical dimension at rest is not stable position and varies following extraction of natural teeth and rehabilitation.

Proteomic analysis of Clostridium thermocellum core metabolism: relative protein expression profiles and growth phase-dependent changes in protein expression.

BACKGROUND: Clostridium thermocellum produces H2 and ethanol, as well as CO2, acetate, formate, and lactate, directly from cellulosic biomass. It is therefore an attractive model for biofuel production via consolidated bioprocessing. Optimization of end-product yields and titres is crucial for making biofuel production economically feasible. Relative protein expression profiles may provide targets for metabolic engineering, while understanding changes in protein expression and metabolism in response to carbon limitation, pH, and growth phase may aid in reactor optimization. We performed shotgun 2D-HPLC-MS/MS on closed-batch cellobiose-grown exponential phase C. thermocellum cell-free extracts to determine relative protein expression profiles of core metabolic proteins involved carbohydrate utilization, energy conservation, and end-product synthesis. iTRAQ (isobaric tag for relative and absolute quantitation) based protein quantitation was used to determine changes in core metabolic proteins in response to growth phase. RESULTS: Relative abundance profiles revealed differential levels of putative enzymes capable of catalyzing parallel pathways. The majority of proteins involved in pyruvate catabolism and end-product synthesis were detected with high abundance, with the exception of aldehyde dehydrogenase, ferredoxin-dependent Ech-type [NiFe]-hydrogenase, and RNF-type NADH:ferredoxin oxidoreductase. Using 4-plex 2D-HPLC-MS/MS, 24% of the 144 core metabolism proteins detected demonstrated moderate changes in expression during transition from exponential to stationary phase. Notably, proteins involved in pyruvate synthesis decreased in stationary phase, whereas proteins involved in glycogen metabolism, pyruvate catabolism, and end-product synthesis increased in stationary phase. Several proteins that may directly dictate end-product synthesis patterns, including pyruvate:ferredoxin oxidoreductases, alcohol dehydrogenases, and a putative bifurcating hydrogenase, demonstrated differential expression during transition from exponential to stationary phase. CONCLUSIONS: Relative expression profiles demonstrate which proteins are likely utilized in carbohydrate utilization and end-product synthesis and suggest that H2 synthesis occurs via bifurcating hydrogenases while ethanol synthesis is predominantly catalyzed by a bifunctional aldehyde/alcohol dehydrogenase. Differences in expression profiles of core metabolic proteins in response to growth phase may dictate carbon and electron flux towards energy storage compounds and end-products. Combined knowledge of relative protein expression levels and their changes in response to physiological conditions may aid in targeted metabolic engineering strategies and optimization of fermentation conditions for improvement of biofuels production.

Mitochondrial dysfunction resulting from the absence of mitochondrial porin in Neurospora crassa.

Porin, the voltage-dependent anion-selective channel (VDAC) in the mitochondrial outer membrane, contributes to metabolism and apoptosis. VDAC function was investigated in Neurospora, an obligate aerobe with a single porin. Porinless strains are viable, with cold-sensitive growth, cytochrome deficiencies and overexpression of alternative oxidase. iTRAQ labeling of mitochondria from a porinless strain and its progenitor revealed a small group of proteins with altered expression levels in the mutant organelles. Porinless Neurospora appears to compensate not by inducing alternative pores, but by altering electron flow and nucleotide metabolism. Transcriptional and post-transcriptional mechanisms contribute to the response, reflecting the extent of porin influence.

Assessment of the reproducibility of random hexapeptide peptide library-based protein normalization.

The wide dynamic range of proteins in biological samples poses a challenge for the detection of low-abundance proteins. Recently, combinatorial hexapeptide peptide libraries have been suggested as an approach to normalization of proteins in such mixtures. We examined the reproducibility of a commercial hexapeptide ligand library for quantitative and comparative serum proteomic analysis. We also compared this technology with IgY-based affinity depletion.

The effects of infliximab therapy on the serum proteome of rheumatoid arthritis patients.

INTRODUCTION: Although the clinical effects of infliximab therapy in rheumatoid arthritis have been documented extensively, the biological effects of this intervention continue to be defined. We sought to examine the impact of infliximab therapy on the serum proteome of rheumatoid arthritis patients by means of a mass spectrometry-based approach. METHODS: Sera from 10 patients with rheumatoid arthritis were obtained prior to and following 12 weeks of infliximab therapy using a standard clinical protocol. The sera were immunodepleted of the 12 highest abundance proteins, labeled by the iTRAQ (isobaric tagging for relative and absolute protein quantification) technique, and analyzed by mass spectrometry to identify proteomic changes associated with treatment. RESULTS: An average of 373 distinct proteins were identified per patient with greater than 95% confidence. In the 3 patients demonstrating the most robust clinical responses, changes of greater than 20% in the serum levels were observed in 39 proteins following treatment. The majority of these proteins were regulated directly or indirectly by tumour necrosis factor-alpha (TNF-alpha) and nuclear factor-kappa-B, with acute-phase proteins being uniformly down-regulated. A number of proteins, including members of the SERPIN family and S100A8, were down-regulated irrespective of clinical response. CONCLUSIONS: The present study demonstrates that a robust clinical response to infliximab is associated with the down-regulation of a spectrum of serum proteins regulated by TNF-alpha, and provides a possible basis for defining the broader biological effects of the treatment in vivo.

Low-cost dual-action aural foreign-body extractor.

Adequate visualization, appropriate equipment, a cooperative patient, and a skilled physician are keys to successful foreign body removal. The first attempt at removal is critical because success rates markedly decrease after the first failed attempt.

Lymphadenovarix of the head-neck region--a rare presentation of Bancroftian filariasis.

Cystic swellings of the neck in children have limited differential diagnoses, often either lymphatic or vascular malformations. Other cystic inflammations can be the result of tuberculous abscesses, suppurated lymph nodes and actinomycosis. Microfilaria causing lmphadenovarix of head-neck region has not yet been described in the literature. A 10-year-old Indian boy presented with an asymptomatic cystic neck mass of 8 months duration. Aspiration of the swelling demonstrated numerous Wuchereria bancrofti microfilaria and the patient responded well to 6 weeks of daily anti-filarial treatment using diethylcarbamazine citrate (6mg kg(-1) day(-1)). This appears to be the first report of microfilariae-associated lymphadenovarix of head-neck region. Though rare, filariasis should be considered as a differential diagnosis for aberrant swellings where lymphatic filarids are endemic.

Mucosal melanoma of nasal cavity and paranasal sinus.

Mucosal melanoma of the nasal cavity and paranasal sinuses is seldom encountered in routine ENT practice. These tumors have poor prognosis owing to higher rates of locoregional recurrence and distant metastasis. Various treatment modalities have been employed over time but the ideal treatment approach still remains an open issue. This article presents some commonly accepted guidelines in treating these rare mucosal neoplasms.

Practical implementation of 2D HPLC scheme with accurate peptide retention prediction in both dimensions for high-throughput bottom-up proteomics.

We describe the practical implementation of a new RP (pH 10 - pH 2) 2D HPLC-ESI/MS scheme for large-scale bottom-up analysis in proteomics. When compared to the common SCX-RP approach, it provides a higher separation efficiency in the first dimension and increases the number of identified peptides/proteins. We also employed the methodology of our sequence-specific retention calculator (SSRCalc) and developed peptide retention prediction algorithms for both LC dimensions. A diverse set of approximately 10,000 tryptic peptides from the soluble protein fraction of whole NK-type cells gave retention time versus hydrophobicity correlations, with R (2) values of 0.95 for pH 10 and 0.945 for pH 2 (formic acid) separation modes. The superior separation efficiency and the ability to use retention prediction to filter out false-positive MS/MS identifications gives promise that this approach will be a method of choice for large-scale proteomics analyses in the future. Finally, the "semi-orthogonal" separation selectivity permits the concatenation of fractions in the first dimension of separation before the final LC-ESI MS step, effectively cutting the analysis time in half, while resulting in a minimal reduction in protein identification.