Monolithic Dual Mobility Cup Total Hip Arthroplasty Has High Complication Rates With Surgical Fixation in Elderly With Femur Neck Fracture.

BACKGROUND: This study is prospectively conducted to evaluate surgical complications of monolithic dual mobility cup total hip arthroplasty (THA) in elderly patients with fractured neck of the femur. METHODS: Ninety-seven patients (97 hips) with displaced femoral neck fracture who gave informed consent for participation were prospectively enrolled. Their mean age was 76.6 years (range, 60-95 years), and the mean bone mineral density T-score of neck of the femur was -2.8 (range, -1.2 to -5.5). All patients underwent THA with monolithic dual mobility cup, and computed tomography scans were obtained to evaluate radiographic parameters including anteversion, inclination, and loosening of acetabular cups, and periprosthetic acetabular fractures. RESULTS: With regard to cup orientation, mean inclination angle was 40.2° (range, 23.5°-63°) and mean anteversion was 32.6° (range, 7°-66.2°). The proportion of surgical outliers was 10.3% (10/97) in inclination and 35.1% (34/97) in anteversion. Early cup loosening within 2 weeks was detected in 2 hips. Periprosthetic acetabular fractures were identified in 6 hips (6/97, 6.2%). Of the 6 fractures, 5 nondisplaced fractures were healed with conservative management, but 1 fracture with displacement eventually led to cup loosening and the patient underwent revision surgery. Reoperation rate of the monolithic dual mobility cup was 4.1% (4/97). CONCLUSION: The use of the monolithic dual mobility was associated with improper cup fixation and periprosthetic acetabular fractures in the elderly with poor bone stock, although the dual mobility cup lowered the risk of early dislocation after THA.

A Comparative Study of the Shear and Tensile Bond Strength using three types of Direct Bonding Adhesives on Stainless Steel Brackets - An In Vitro Study.

BACKGROUND: The purpose of this study was to compare the shear and tensile bond strength of three adhesive systems with increasing concentrations of filler for bonding brackets. MATERIALS & METHODS: The study was carried out on 120 extracted human premolars; randomly divided into six groups, three groups for shear bond strength & three for tensile bond strength, each subgroup consisting of 20 teeth; using light cured adhesive systems: Group 1: FORTIFY Unfilled, (unfilled penetrating resin) Group 2: ALITEF Low Filled (filler load 58% by weight) Group 3: PYRAMID Highly Filled (filler load greater than 80% by weight) with metal brackets (TP 256-650. TP orthodontic inc. Po.box 73,La Porte 46350,USA). RESULTS: The findings showed that in vitro tensile bond strength and shear bond strength of PYRAMID [9.88/11.46 MPa resp.] is significantly greater than ALITEFLO[5.34/9.50 MPa resp.] and FORTIFY [2.65/5.39 MPa resp.]. CONCLUSION: Using the same bracket and force mode but different adhesive filler concentrations revealed increased shear and tensile bond strength with increased filler concentration. How to cite this article: Kumar PS, Patil C, Hullal B, Putturaj KT, Sangolgi VC, Jayasudha K. A Comparative Study of the Shear and Tensile Bond Strength using three types of Direct Bonding Adhesives on Stainless Steel Brackets - An In Vitro Study. J Int Oral Health 2013; 5(4):26-29.

An experimental study of arch perimeter and arch width increase with mandibular expansion: a finite element method.

AIMS: The objective of this study was to estimate the increase in arch perimeter associated with mandibular lateral expansion, To estimate the increase in intermolar width with mandibular lateral expansion and to find out the changes of tooth inclination with mandibular expansion. MATERIALS AND METHODS: The mandibular bone with dentition of indian skeletal specimen was obtained. The computer tomogram (CT) slices of the mandible were taken. Finite element model (FEM): Numerical representation of the geometry was created by dividing the geometry into finite number of elements and the elements were connected together with nodes at the junction. RESULTS: The result of the study showed when 10° of lateral expansion was applied to the lower buccal segment at the center of rotation found at 4.3 mm below the root apex of first molar, a space of 1.3 mm between the canine and first premolar, and thus an increase in arch perimeter of 2.6 mm. CONCLUSION: The tip of the mesiolingual cusp of the first molar moved 4.2 mm laterally, resulting in a change in intermolar width by 8.4 mm. Three-dimensional simulation showed that 1 mm of intermolar expansion increased the arch perimeter by 0.30 mm. CLINICAL SIGNIFICANCE: As the finite element method evolves and scientists are able to more clearly define physical properties of biological tissues, more accurate information can be generated at the level that other analytical methods cannot fully provide data.This result would be of value clinically for prediction of the effects of mandibular expansion.

Disruption mechanism in the helix of SPF peptide by interchanging E5 and K10 residues: inference from molecular dynamics study.

Seminalplasmin (SPLN) is a 47-residue peptide (SDEKASPDKHHRFSLSRYAKLANRLANPKLLETFLSKWIGDRGNRSV) from bovine seminal plasma. It has broad spectrum antimicrobial activity, without any hemolytic activity. The 28-40 segment of SPLN with the sequence PKLLETFLSKWIG, designated as SPF, is the most hydrophobic stretch of SPLN and primarily responsible for the membrane-perturbing activity of SPLN. It was reported that SPF has a helical structure and the interchange of E5 and K10 residues disrupted the helical structure. The present paper reports a possible mechanism of disruption of the helical structure of SPF peptide during the interchange of E5 and K10 residues. The result is based on simulated annealing and molecular dynamics simulation studies on SPF and its four analogues with K10E, K10D, E5K, and E5K & K10E substitutions. It showed that K10 residue has a critical role in maintaining the highest helical content and the positions of charged residues are also very important for maintaining the helical structure of the SPF peptide. Formation of some new long-range hydrogen bonds and the rupture of some short-range hydrogen bonds involving the tenth residue led to the disruption of helical structure of SPF peptide when E5 and K10 residues are interchanged.

Modeling of factor XIII activation peptide (28-41) V34L mutant bound to thrombin.

Factor XIII (FXIII) is a transglutaminase involved in blood coagulation. The enzyme is activated by thrombin cleaving the peptide bond R37-G38. A common mutation V34L found in FXIII has been correlated with protection from myocardial infarction. Also FXIII V34L is activated more quickly than the wild type. In the present study, FXIII (28-41) V34L mutant peptide bound to thrombin has been modeled and molecular dynamics simulations were carried out using Insight II. An average structure was calculated after simulation. The structure showed significant difference from the crystal structure of the wild type FXIII (28-37) peptide bound to thrombin. In the crystal structure the peptide adopts a folded conformation in such a way that the hydrophobic side chains of V29 and V34 occupy the apolar binding site of thrombin. The modeled V34L peptide adopts a significantly different conformation and only the bulkier L34 occupies the apolar binding site while V29 side chain is exposed to the bulk solvent. Hence, this may speed up the release of FXIII from thrombin after its activation.

Conformation of an octapeptide fragment (2-9) of kaliocin-1 in DMSO-d6 by 1H NMR and restrained molecular dynamics.

Kaliocin-1, a 31-residue synthetic peptide (FFSASCVPGADKGQFPNLCRLCA GTGENKCA), which has shown the antimicrobial activity forms the 152-182 fragment of human lactoferrin (HLf). As the octapeptide FSASCVPG forms the 2-9 fragment of kaliocin-1, in the present study, its conformation in dimethyl sulfoxide-d6 (DMSO-d6) has been determined using two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy as well as restrained molecular dynamics. Sequence specific assignments of all the 1H resonances have been carried out using 2D correlation experiments (2D DQF-COSY, TOCSY and ROESY). In dimethyl sulfoxide-d6 at 25 degrees C, the octapeptide adopts a predominantly extended backbone conformation. The calculated structure resembles closely with the reported structure of the corresponding fragment of HLf. The peptide also has sequence and structural similarity with the corresponding fragments of lactoferrins from other organisms.