bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternative strategies for the study and treatment of clinical bacterial biofilms
Authors: Belanger Corrie R. , Mansour Sarah C. , Pletzer Daniel , Hancock Robert E.W.
Published: April 2017

Biofilms represent an adaptive lifestyle where microbes grow as structured aggregates in many different environments, e.g. on body surfaces and medical devices. They are a profound threat in medical (and industrial) settings and cause two-thirds of all infections. Biofilm bacteria are especially recalcitrant to common antibiotic treatments, demonstrating adaptive multidrug resistance. For this reason, novel methods to eradicate or prevent biofilm infections are greatly needed. Recent advances have been made in exploring alternative strategies that affect biofilm lifestyle, inhibit biofilm formation, degrade biofilm components and/or cause dispersal. As such, naturally derived compounds, molecules that interfere with bacterial signaling systems, anti-biofilm peptides and phages show great promise. Their implementation as either stand-alone drugs or complementary therapies has the potential to eradicate resilient biofilm infections. Additionally, altering the surface properties of indwelling medical devices through bioengineering approaches has been examined as a method for preventing biofilm formation. There is also a need for improving current biofilm detection methods since in vitro methods often do not accurately measure live bacteria in biofilms or mimic in vivo conditions. We propose that the design and development of novel compounds will be enabled by the improvement and use of appropriate in vitro and in vivo models.
Empirical mode decomposition based on instantaneous frequency boundary
Authors: Li Jiafu , Wang Jun , Zhang Xiaolin , Tang Wenyan
Published: April 2017

A method for the adaptive signal decomposition by using the frequency boundary information is proposed. This is achieved by the high‐order derivative operation that could extract the frequency‐domain boundary between the highest frequency portion and the rest parts of signal by using the proper order value and a subsection filtering method based on fast Fourier transform. Simulations show that the proposed method performs better in frequency resolution, modal aliasing than empirical mode decomposition, ensemble empirical mode decomposition (EEMD) and complementary ensemble empirical mode decomposition (CEEMD).
Liquid‐metal capacitors with a 42:1 tuning ratio
Authors: Rahman M.A. , Shiroma W.A. , Ohta A.T.
Published: April 2017

Four types of liquid‐metal‐based tunable capacitors with a high tuning range are demonstrated. The capacitors are easily fabricated by placing a pair of liquid‐metal‐filled tubes in contact with one another. Tunability is achieved by varying the length of the liquid metal in one of the tubes using a mechanical pump. Four different structures are demonstrated: parallel‐tube, folded‐tube, coil, and spiral capacitors. The highest measured tuning ratio is 42:1, and the highest change in capacitance per unit length of the pumped liquid metal is 0.07 pF/mm.
Gain and side‐lobe improvement of W‐band microstrip array antenna with CSRR for radar applications
Authors: Dewantari Aulia , Kim Jaeheung , Jeon Se‐Yeon , Kim Seok , Ka Min‐Ho
Published: April 2017

A new method for suppressing surface waves on a millimetre‐wave microstrip array antenna is presented. A 10 × 2 patch array antenna is designed at 77 GHz for W‐band radar applications. Complementary split ring resonator (CSRR) has been designed at 77 GHz, etched on the antenna ground plane. Simulation and experimental results are compared in terms of the gain and the side lobe level with and without CSRR. CSRR between series patch antenna array could suppress surface waves effectively so that this approach enhances the gain and reduces the side lobe level. The measured gain improvement in the antenna with CSRR is 2.5 dB. The side lobe level of the antenna with CSRR is reduced up to 3.5 dB lower than antenna without CSRR.
High voltage gain half‐bridge quasi‐switched boost inverter with reduced voltage stress on capacitors
Authors: Asl Elias Shokati , Babaei Ebrahim , Sabahi Mehran
Published: April 2017

In this study, an improved topology of half‐bridge switched boost inverter with low voltage stress on capacitors is proposed. The proposed half‐bridge quasi‐switched boost inverter, in comparison with the half‐bridge Z‐source inverter with two Z‐networks, has less passive components. Moreover, the proposed topology generates high voltage gain comparing with the conventional topologies and has stable operation. Producing zero voltage level at the output is the other advantage of the proposed inverter, in comparison with the conventional half‐bridge inverter. The small‐signal model and steady‐state analysis of the proposed inverter in different operating modes are given. Moreover, signal flow graph using small‐signal analysis and design considerations are derived. In addition, switching pattern for the proposed inverter is presented and power losses are calculated. A comprehensive comparison is done between the proposed topology and conventional inverters from different points of view such as number of components, volume, inrush current, tolerance of shoot‐through and so on. Finally, the simulation and experimental results are given to demonstrate dynamic response, effect of undesirable shoot‐through and the accuracy of the given theories.
Model predictive current control of surface‐mounted permanent magnet synchronous motor with low torque and current ripple
Authors: Bozorgi Amir Masoud , Farasat Mehdi , Jafarishiadeh Seyyedmahdi
Published: April 2017

Electromagnetic torque and stator flux of a permanent magnet synchronous motor (PMSM) can be controlled indirectly with model predictive current control (MPCC). In MPCC, a predefined cost function is minimised by selecting and applying appropriate voltage vectors to stator terminals. Since MPCC employs machine model to predict stator currents, it requires accurate knowledge of its parameters. Furthermore, MPCC results in high torque and current ripples at normal sampling rates. In this study, torque and current ripples of a surface‐mounted PMSM are effectively reduced by incorporating the concept of duty cycle and applying two voltage vectors, instead of one voltage vector as in conventional MPCC, during a control period. A fuzzy logic modulator is designed and utilised to determine the duty cycles of voltage vectors. Furthermore, sensitivity of the proposed control strategy against parameter variations is alleviated by employing a full‐order Luenberger observer. Various case studies are carried out on a hardware‐in‐the‐loop setup and performance of the proposed method is compared with conventional and a recently introduced duty cycle‐based predictive control. The obtained results verify the superiority of the proposed MPCC and its effectiveness in reducing the PMSM torque and current ripples with accurate and erroneous knowledge of motor parameters.
Hepatitis C virus triggers Golgi fragmentation and autophagy through the immunity-related GTPase M
Authors: Hansen Marianne D. , Johnsen Ingvild B. , Stiberg Kim A. , Sherstova Tatyana , Wakita Takaji , Richard Gabriel Mary , Kandasamy Richard K. , Meurs Eliane F. , Anthonsen Marit W.
Published: April 2017

Significance

Without a vaccine or cost-effective antivirals against hepatitis C virus (HCV) there is a need to understand better the molecular mechanisms underlying the establishment of productive HCV infection and chronic liver disease. Recently, the Crohn's disease and tuberculosis risk factor immunity-related GTPase M (IRGM) was found to promote HCV replication, but the mechanisms involved are unknown. Here we provide mechanistic insight into how IRGM stimulates the two membrane-remodeling pathways, Golgi fragmentation and autophagy, to facilitate HCV replication. Our findings offer insights into the replication strategies used by HCV that should be useful for antiviral approaches. Also, these findings might aid understanding how IRGM functions in infection and inflammation in the setting of other diseases, e.g., in Crohn’s disease.
Parallel adaptive evolution of geographically distant herring populations on both sides of the North Atlantic Ocean
Authors: Lamichhaney Sangeet , Fuentes-Pardo Angela P. , Rafati Nima , Ryman Nils , McCracken Gregory R. , Bourne Christina , Singh Rabindra , Ruzzante Daniel E. , Andersson Leif
Published: April 2017

Significance

Identification of genetic changes that allow a species to adapt to different environmental conditions is an important topic in evolutionary biology. In this study we analyzed whole-genome resequencing data of Atlantic herring populations from both sides of the Atlantic Ocean and identified a number of loci that show consistent associations with spawning time (spring or autumn). Several of these loci, such as thyroid-stimulating hormone receptor (TSHR), have a well-established role in reproductive biology, whereas others have never been implicated in controlling reproduction. Genetic variants associated with adaptation to spring or autumn spawning are shared to a large extent among populations across the Atlantic Ocean and the Baltic Sea, providing evidence for parallel adaptive evolution.
Infinitely productive language can arise from chance under communicative pressure
Authors: Piantadosi Steven T. , Fedorenko Evelina
Published: April 2017

Human communication is unparalleled in the animal kingdom. The key distinctive feature of our language is productivity: we are able to express an infinite number of ideas using a limited set of words. Traditionally, it has been argued or assumed that productivity emerged as a consequence of very specific, innate grammatical systems. Here we formally develop an alternative hypothesis: productivity may have rather solely arisen as a consequence of increasing the number of signals (e.g. sentences) in a communication system, under the additional assumption that the processing mechanisms are algorithmically unconstrained. Using tools from algorithmic information theory, we examine the consequences of two intuitive constraints on the probability that a language will be infinitely productive. We prove that under maximum entropy assumptions, increasing the complexity of a language will not strongly pressure it to be finite or infinite. In contrast, increasing the number of signals in a language increases the probability of languages that have—in fact—infinite cardinality. Thus, across evolutionary time, the productivity of human language could have arisen solely from algorithmic randomness combined with a communicative pressure for a large number of signals.
Brachial Arterial Pressure Monitoring during Cardiac Surgery Rarely Causes Complications
Authors: Singh Asha , Bahadorani Bobby , Wakefield Brett J. , Makarova Natalya , Kumar Priya A. , Tong Michael Zhen-Yu , Sessler Daniel I. , Duncan Andra E.
Published: April 2017

Background

Brachial arterial catheters better estimate aortic pressure than radial arterial catheters but are used infrequently because complications in a major artery without collateral flow are potentially serious. However, the extent to which brachial artery cannulation promotes complications remains unknown. The authors thus evaluated a large cohort of cardiac surgical patients to estimate the incidence of related serious complications.

Methods

The institutional Society of Thoracic Surgeons Adult Cardiac Surgery Database and Perioperative Health Documentation System Registry of the Cleveland Clinic were used to identify patients who had brachial artery cannulation between 2007 and 2015. Complications within 6 months after surgery were identified by International Classification of Diseases, Ninth Revision diagnostic and procedural codes, Current Procedural Terminology procedure codes, and Society of Thoracic Surgeons variables. The authors reviewed electronic medical records to confirm that putative complications were related plausibly to brachial arterial catheterization. Complications were categorized as (1) vascular, (2) peripheral nerve injury, or (3) infection. The authors evaluated associations between brachial arterial complications and patient comorbidities and between complications and in-hospital mortality and duration of hospitalization.

Results

Among 21,597 qualifying patients, 777 had vascular or nerve injuries or local infections, but only 41 (incidence 0.19% [95% CI, 0.14 to 0.26%]) were potentially consequent to brachial arterial cannulation. Vascular complications occurred in 33 patients (0.15% [0.10 to 0.23%]). Definitely or possibly related infection occurred in 8 (0.04% [0.02 to 0.08%]) patients. There were no plausibly related neurologic complications. Peripheral arterial disease was associated with increased risk of complications. Brachial catheter complications were associated with prolonged hospitalization and in-hospital mortality.

Conclusions

Brachial artery cannulation for hemodynamic monitoring during cardiac surgery rarely causes complications.
Intramedullary Nail Fixation of Atypical Femur Fractures With Bone Marrow Aspirate Concentrate Leads to Faster Union: A Case–Control Study
Authors: Lovy Andrew J. , Kim Jun S. , Di Capua John , Somani Sulaiman , Shim Stephanie , Keswani Aakash , Hasija Rohit , Wu Yangguan , Joseph David , Ghillani Richard
Published: April 2017

Objectives:

To evaluate bone marrow aspirate concentrate (BMAC) use in the treatment of AFF.

Design:

Retrospective case control.

Setting:

Level 1 trauma center.

Patients:

Complete AFF, defined according to American Society of Bone and Mineral Research (ASBMR) criteria, from September 2009 to April 2015 with minimum 1-year follow-up.

Intervention:

Operative treatment with antegrade intramedullary nails. Beginning June 2014, BMAC from the ipsilateral iliac crest was added to all AFFs.

Main Outcome Measurements:

Time to union as determined by a blinded panel of 3 attending orthopaedic surgeons, union rates, complications.

Results:

Thirty-five patients with 36 AFFs were reviewed, of which 33 AFFs were included and 11 received BMAC. Alendronate was the most commonly prescribed bisphosphonate, with a similar mean duration of use in controls and BMAC cases (5.6 versus 6 years, P = 0.79). BMAC use significantly decreased time to union (3.5 versus 6.8 months, P = 0.004). Varus malreduction was associated with a significant delay in union (9.7 versus 4.7 months, P = 0.04). Overall, 1 year union rate was 86.2% and nonsignificantly higher in BMAC compared with controls (100.0% versus 77.3%, P = 0.11). Multivariate analysis revealed BMAC and varus malreduction as independent predictors of time to union. There were no complications related to BMAC use.

Conclusion:

Our findings support intramedullary nailing of AFFs as an effective treatment option with a low surgical complication rate and highlight the importance of avoiding varus malreduction. BMAC use significantly reduced time to fracture union without an increase in surgical complication rates.

Level of Evidence:

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Implant Material, Type of Fixation at the Shaft, and Position of Plate Modify Biomechanics of Distal Femur Plate Osteosynthesis
Authors: Kandemir Utku , Augat Peter , Konowalczyk Stefanie , Wipf Felix , von Oldenburg Geert , Schmidt Ulf
Published: April 2017

Objectives:

To investigate whether (1) the type of fixation at the shaft (hybrid vs. locking), (2) the position of the plate (offset vs. contact) and (3) the implant material has a significant effect on (a) construct stiffness and (b) fatigue life in a distal femur extraarticular comminuted fracture model using the same design of distal femur periarticular locking plate.

Methods:

An extraarticular severely comminuted distal femoral fracture pattern (OTA/AO 33-A3) was simulated using artificial bone substitutes. Ten-hole distal lateral femur locking plates were used for fixation per the recommended surgical technique. At the distal metaphyseal fragment, all possible locking screws were placed. For the proximal diaphyseal fragment, different types of screws were used to create 4 different fixation constructs: (1) stainless steel hybrid (SSH), (2) stainless steel locked (SSL), (3) titanium locked (TiL), and (4) stainless steel locked with 5-mm offset at the diaphysis (SSLO). Six specimens of each construct configuration were tested. First, each specimen was nondestructively loaded axially to determine the stiffness. Then, each specimen was cyclically loaded with increasing load levels until failure.

Results:

Construct Stiffness: The fixation construct with a stainless steel plate and hybrid fixation (SSH) had the highest stiffness followed by the construct with a stainless steel plate and locking screws (SSL) and were not statistically different from each other. Offset placement (SSLO) and using a titanium implant (TiL) significantly reduced construct stiffness. Fatigue Failure: The stainless steel with hybrid fixation group (SSH) withstood the most number of cycles to failure and higher loads, followed by the stainless steel plate and locking screw group (SSL), stainless steel plate with locking screws and offset group (SSLO), and the titanium plate and locking screws group (TiL) consecutively. Offset placement (SSLO) as well as using a titanium implant (TiL) reduced cycles to failure.

Conclusions:

Using the same plate design, the study showed that implant material, screw type, and position of the plate affect the construct stiffness and fatigue life of the fixation construct. With this knowledge, the surgeon can decide the optimal construct based on a given fracture pattern, bone strength, and reduction quality.
Optimizing Radiation Dose in Computed Tomography of Articular Fractures
Authors: Mansfield Colin , Ali Sayed , Komperda Kazimierz , Zhao Huaqing , Rehman Saqib
Published: April 2017

Objectives:

To determine whether a substantially lowered radiation protocol would provide satisfactory information for the surgeon, using the distal tibia as a model.

Methods:

Eleven adult cadaveric distal tibia specimens were used to create Orthopaedic Trauma Association (OTA/AO) 43C distal tibia fractures with varying displacements in 2 planes. Each specimen was scanned at 3 modified protocols, which were then subsequently read by both qualified attending orthopaedists and midlevel residents. Observer reliability was evaluated, as well as confidence levels of identifying fracture pattern and treatment protocols.

Results:

On average, there was less than a millimeter of variability in the measured gap to true gap as a whole (mean = 0.74 mm, P < 0.0001). With regard to measurements in gap, pattern, and treatment plans, no significant difference was found between CT images acquired with standard (110 mAs) compared with medium (60 mAs; mean 0.0 mm, P = 1.0; k = 0.14, P = 0.56; k = 0.38, P = 0.13, respectively) and low protocols (45 mAs; mean 0.01 mm, P = 0.95; k = 0.24, P = 0.32; k = 0.31, P = 0.13, respectively). Furthermore, no significant difference was found in measuring step-off across standard, medium, and low radiation dose (0.21 mm, P = 0.46; 0.28 mm, P = 0.39; −0.16 mm, P = 0.48, respectively).

Conclusion:

The results of this study show no significant difference when evaluating current standard and low-dose CT scans using less than one-half the amount of exposure. This suggests that in complex extremity fractures, a new CT protocol may potentially be used. Our initial data show promise that we may retain satisfactory imaging to formulate a treatment plan while also reducing the collective radiation burden to the population.
Triplanar Humeral Osteotomy for Restoration of Midline Function in Patients With Brachial Plexus Birth Palsy
Authors: Jennings John D. , Greenhill Dustin A. , Kozin Scott H. , Zlotolow Dan A.
Published: April 2017

Brachial plexus birth palsy resolves spontaneously in a majority of patients, however, others may have serious permanent dysfunction. Although nerve transfers or grafts are early options for treatment, many children have residual deficits or present too late for such procedures. In these patients, rotational osteotomy of the humerus may restore improved function and motion. Unfortunately, traditional humeral osteotomies only provide correction in a single plane, therefore appropriate correction of the typical residual deformity is incomplete. Here, we describe a novel technique for obtaining a calculated correction in 3 planes using a single osteotomy of the humerus on the basis of a mathematical equation. Nine patients are described here with an average of 35.4 months follow-up. Corrections were obtained in adduction, extension, and either internal or external rotation depending on the initial deformity and Modified Mallet scores were collected for each patient. There was 1 case of transient radial nerve palsy with no long-term complications overall.
A Technique for Treating Dorsal Instability of the Distal Radioulnar Joint
Authors: El-Haj Madi , Baughman Carter , Thirkannad Sunil M.
Published: April 2017

We describe a technique for the treatment of chronic dorsal instability of the distal radioulnar joint by creating a strong dorsal radioulnar restraint using opposing flaps from the extensor retinaculum and dorsal capsule of the radioulnar joint. This technique has been used in 18 patients and has proven to be very easy and reliable with all patients demonstrating good stability of the distal radioulnar joint at final follow-up.
Surgical Factors Associated with Prolonged Hospitalization after Reconstruction for Oncological Spine Surgery
Authors: Carl Hannah M. , Coon Devin , Calotta Nicholas A. , Pedreira Rachel , Sacks Justin M.
Published: April 2017

Background:

Posterior trunk reconstruction is increasingly possible as a result of advances in spinal instrumentation, reconstructive approaches, and perioperative critical care. Extensive cases often require a muscle flap or complex closure to obliterate dead space. Postsurgical wound complications and subsequent reoperations can lead to neural injury, higher hospital costs, and longer hospitalizations. We aim to identify risk factors that are associated with increased length of stay (LOS) for patients receiving flaps to close a spinal defect.

Methods:

A single institution, retrospective cohort study was performed on all patients from 2002 to 2014 who received a muscle flap to close a spine defect. Medical and perioperative variables that were significantly associated with LOS (P < 0.05) in univariate analysis were included in a stepwise regression model.

Results:

A total of 288 cases were identified. Presence of instrumentation, preoperative chemotherapy, wound dehiscence, cerebrospinal fluid leak, partial/total flap loss, and medical morbidity occurrence were all independently associated with increased LOS in a combined multivariate model (P < 0.02 for each of the 6 variables). Importantly, Kaplan–Meier analysis demonstrated that postoperative wound dehiscence increased LOS by 12 days.

Conclusions:

Spinal tumor resections often create large cavitary defects that necessitate the use of muscle flaps for closure. Patients who have received adjuvant chemotherapy require instrumentation, or those who develop specific wound-related or medical complications are at increased risk for prolonged hospitalization after spinal reconstruction. Thus, implementing measures to mitigate the occurrence of these adverse events will reduce costs and decrease the length of hospitalization.
Survival Differences in Women with and without Autologous Breast Reconstruction after Mastectomy for Breast Cancer
Authors: L. Semple John , Metcalfe Kelly , Shoukat Farah , Sun Ping , Narod Steven
Published: April 2017

Background:

Breast reconstruction (BR) is an option for women who are treated with mastectomy; however, there has been concern regarding the oncologic safety of BR. In this study, we evaluated recurrences and mortality in women treated with mastectomy and compared outcomes in those treated with mastectomy alone to those with mastectomy plus transverse rectus adbominis (TRAM) flap BR.

Methods:

The prospective cohort study included women treated with mastectomy at Women’s College Hospital from 1987 to 1997. Women with TRAM flap BR were matched to controls based on age and year of diagnosis, stage, and nodal status. Patients were followed from the date of diagnosis until death or date of last follow-up. Hazard ratios were generated to compare cases and controls for outcome variables using Cox’s proportional hazards models.

Results:

Of 443 women with invasive breast cancer, 85 subjects had TRAM flap BR. Sixty-five of these women were matched to 115 controls. The mean follow-up was 11.2 (0.4–26.3) years. There were no significant differences between those with and without BR with weight, height, or smoking status. Women with TRAM flap were less likely to experience a distant recurrence compared to women without a TRAM flap (relative risk, 0.42; P = 0.0009) and were more likely to be alive (relative risk, 0.54; P = 0.03).

Conclusions:

Women who elect for TRAM flap BR after an invasive breast cancer diagnosis do have lower rates of recurrences and mortality than women treated with mastectomy alone. This cannot be explained by differences in various clinical or lifestyle factors.
Reconstructing Discontinuous Facial Defects with Simultaneous Ulnar Perforator Free Flaps
Authors: Thomas Carissa M. , Sokoya Mofiyinfolu , Deleyiannis Frederic W.-B.
Published: April 2017

Multiple, simultaneous skin cancers of the face are common. This is the first description of reconstructing discontinuous facial defects (i.e., separate sites of the face) with simultaneous ulnar perforator flaps. The distinct innovations of this multiple flap design are the ability to restrict the harvest site to one extremity, to obtain vein and arterial grafts from the same extremity, and to create multiple flaps with minimal hirsutism and bulk. We present a case of a 57-year-old male with multiple basal cell carcinomas who underwent wide local excisions of the right upper lip and cheek and of the left lower eyelid and infraorbital cheek. Two left-sided ulnar perforator free flaps were used for reconstruction with the outcome of normal oral competence and eyelid function. When faced with discontinuous facial defects, reconstruction with simultaneous ulnar perforator flaps is a useful option because of the advantages of matching the thinness and pliability of the resected skin, reducing the number of harvest sites and preventing the distortion and contraction that can be seen with local advancement flaps or skin grafts.
Rab7—a novel redox target that modulates inflammatory pain processing
Authors: Kallenborn-Gerhardt Wiebke , Möser Christine V. , Lorenz Jana E. , Steger Mirco , Heidler Juliana , Scheving Reynir , Petersen Jonas , Kennel Lea , Flauaus Cathrin , Lu Ruirui , Edinger Aimee L. , Tegeder Irmgard , Geisslinger Gerd , Heide Heinrich , Wittig Ilka , Schmidtko Achim
Published: April 2017

Chronic pain is accompanied by production of reactive oxygen species (ROS) in various cells that are important for nociceptive processing. Recent data indicate that ROS can trigger specific redox-dependent signaling processes, but the molecular targets of ROS signaling in the nociceptive system remain largely elusive. Here, we performed a proteome screen for pain-dependent redox regulation using an OxICAT approach, thereby identifying the small GTPase Rab7 as a redox-modified target during inflammatory pain in mice. Prevention of Rab7 oxidation by replacement of the redox-sensing thiols modulates its GTPase activity. Immunofluorescence studies revealed Rab7 expression to be enriched in central terminals of sensory neurons. Knockout mice lacking Rab7 in sensory neurons showed normal responses to noxious thermal and mechanical stimuli; however, their pain behavior during inflammatory pain and in response to ROS donors was reduced. The data suggest that redox-dependent changes in Rab7 activity modulate inflammatory pain sensitivity.
Calculating the Tumor Volumes in Vestibular Schwannomas: Are the ABC/2 and Volumetric Methods Comparable?
Authors: Bathla Girish , Policeni Bruno , Hansen Marlan R. , Berbaum Kevin
Published: April 2017

Purpose:

To assess the efficacy of the ABC/2 method for calculating the volume of vestibular schwannomas as compared with 3-D planimetric method.

Study Design:

Retrospective.

Methods:

Fifty eight cases of pathologically confirmed sporadic vestibular schwannomas (VS) were analyzed. Tumors volumes were calculated for each tumor twice, once through semiautomated 3-D volumetric method and subsequently through ABC/2 (AP × ML × CC/2) methodology after calculating the maximal tumor dimensions in anteroposterior (AP), coronal (ML), and craniocaudal (CC) dimensions. Tumor volumes were initially correlated as a group and subsequently by dividing them into three groups using the Hannover classification.

Results:

The two methodologies were highly correlated when tumors were analyzed as a group (rho = 0.913, p < 0.0001). In the sub-group analysis, tumor volumes were again strongly correlated for larger tumors (rho = 0.918, p < 0.0001) but the correlation progressively reduced as tumor volumes decreased.

Conclusion:

Given the ease and universal accessibility of linear measurement applications, the ABC/2 methodology is a robust substitute for calculating tumor volumes, especially for larger tumors.
Brain Magnetic Resonance Imaging Findings in Pediatric Patients Post Extracorporeal Membrane Oxygenation
Authors: Pinto Venessa L. , Pruthi Sumit , Westrick Ashly C. , Shannon Chevis N. , Bridges Brian C. , Le Truc M.
Published: April 2017

Neurologic complications can occur with extracorporeal membrane oxygenation (ECMO) due to several factors. Prior studies identified neonates as having unique risk factors and neuroimaging findings post ECMO. The aim of this study is to describe brain magnetic resonance imaging findings of pediatric patients treated with ECMO. We conducted a retrospective study of nonneonatal pediatric patients who underwent a comprehensive brain magnetic resonance imaging after ECMO between January 2000 and July 2015. We identified 47 pediatric patients in the study cohort with a median age of 8 months (interquartile range 3–170 months) and a median ECMO run duration of 7.15 days (interquartile range 3.8–10.3 days). Among indications for ECMO cannulation, 12 (25.5%) were cardiac, 23 (48.9%) were respiratory, and 12 (25.5%) were extracorporeal cardiopulmonary resuscitation cannulations. There were 33 (70.2%) veno-arterial cannulations of which 14 (42%) were transthoracic cannulations. There were 13 patients (27.7%) with an overall incidence of stroke: 8 patients had exclusive ischemic strokes, 2 had hemorrhagic strokes, and 3 had mixed types of stroke. The number of strokes in patients on veno-arterial ECMO was significantly decreased in patients undergoing transthoracic cannulation when compared with peripheral cannulation (7 vs. 42%, p = 0.05). Further study will be used to identify risk factors for neurological injury after ECMO and to look for outcome predictors based on neuroradiologic findings.
Percutaneous Mechanical Circulatory Support Using Impella Devices for Decompensated Cardiogenic Shock: A Pediatric Heart Center Experience
Authors: Parekh Dhaval , Jeewa Aamir , Tume Sebastian C , Dreyer William J. , Pignatelli Ricardo , Horne David , Justino Henri , Qureshi Athar M.
Published: April 2017

Cardiogenic shock remains a significant cause of mortality and morbidity in children with heart failure. Percutaneous mechanical circulatory support may be an additional tool to augment left heart support and decompression in addition to conventional therapies. This report aims to review the clinical and hemodynamic outcomes of the Impella device at a pediatric center. A retrospective review of all implants between October 2014 and November 2016 was conducted. Clinical outcomes, device implant techniques, complications, and hemodynamic data were collected. Statistical analysis was performed on hemodynamic and echocardiographic data. There were 10 Impella device placements in 8 patients with a median age of 17 years (6.5–25) and support duration of 8 days (1–21). Implant diagnosis included 5 patients with either posttransplant rejection or allograft vasculopathy, 2 patients with myocarditis, and 1 patient with refractory ventricular tachycardia. Extracorporeal membrane oxygenation support was required in 4 patients. Significant reduction in pulmonary capillary wedge pressures/left atrial pressures (p = 0.031) and increase in near infrared spectroscopy (p = 0.039) was seen pre- and post-Impella implant. All patients survived to discharge from the intensive care unit with one late death. Percutaneous mechanical circulatory support is a viable option in experienced pediatric centers as a mode to augment cardiac output or to decompress the left heart in patients on extracorporeal membrane oxygenation or with cardiogenic shock.
Comparative Bone Regeneration Potential Studies of Collagen, Heparin, and Polydopamine-Coated Multichannelled BCP Granules
Authors: Lee Gun Hee , Makkar Preeti , Paul Kallyanshis , Lee Byong Taek
Published: April 2017

The current study is a comparative assessment of the bone regeneration potentiality of bone substitutes composed of bioactive polymer–coated biphasic calcium phosphate (BCP) granules. The bone substitutes were primarily composed of multichanneled BCP granules, which were coated separately with biochemical polymer coatings, namely collagen, heparin, or polydopamine (PD), using chemical methods. The morphologic features and chemical structure of the granules and surface coatings were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The biological characterizations in terms of cellular interaction with the bone substitutes in vitro (MTT assay and proliferation) and in vivo (bone regeneration efficacy) were performed and compared with uncoated BCP granules. It was found that PD-coated BCP granules were superior to the others with respect to promoting more rapid healing. Therefore, PD multichannel BCP granule system can be used as a promising injectable bone substitute for clinical applications.
Normothermic Ex Vivo Heart Perfusion: Effects of Live Animal Blood and Plasma Cross Circulation
Authors: Church Joseph T. , Alghanem Fares , Deatrick Kristopher B. , Trahanas John M. , Phillips Joseph P. , Hee Song Min , Perkins Elena M. , Bartlett Robert H. , Rojas-Pena Alvaro , Bocks Martin L. , Owens Gabe E.
Published: April 2017

Prolonged normothermic ex vivo heart perfusion could transform cardiac transplantation. To help identify perfusate components that might enable long-term perfusion, we evaluated the effects of cross-circulated whole blood and cross-circulated plasma from a live paracorporeal animal on donor porcine hearts preserved via normothermic ex vivo heart perfusion. Standard perfusion (SP; n = 40) utilized red blood cell/plasma perfusate and Langendorff technique for a goal of 12 hours. Cross-circulation groups used a similar circuit with the addition of cross-circulated venous whole blood (XC-blood; n = 6) or cross-circulated filtered plasma (XC-plasma; n = 7) between a live paracorporeal pig under anesthesia and the perfusate reservoir. Data included oxygen metabolism, vascular resistance, lactate production, left ventricular function, myocardial electrical impedance, and histopathologic injury score. All cross-circulation hearts were successfully perfused for 12 hours, compared with 22 of 40 SP hearts (55%; p = 0.002). Both cross-circulation groups demonstrated higher oxygen consumption and vascular resistance than standard hearts from hours 3–12. No significant differences were seen between XC-blood and XC-plasma hearts in any variable, including left ventricular dP/dT after 12 hours (1478 ± 700 mm Hg/s vs. 872 ± 500; p = 0.17). We conclude that cross circulation of whole blood or plasma from a live animal improves preservation of function of perfused hearts, and cross-circulated plasma performs similarly to cross-circulated whole blood.
Cardiopulmonary monitoring of shock
Authors: Simmons James , Ventetuolo Corey E.
Published: April 2017

Purpose of review

We will briefly review the classification of shock and the hallmark features of each subtype. Available modalities for monitoring shock patients will be discussed, along with evidence supporting the use, common pitfalls, and practical considerations of each method.

Recent findings

As older, invasive monitoring methods such as the pulmonary artery catheter have fallen out of favor, newer technologies for cardiac output estimation, echocardiography, and noninvasive tests such as passive leg raising have gained popularity. Newer forms of minimally invasive or noninvasive monitoring (such as pulse contour analysis and chest bioreactance) show promise but will need further investigation before they are considered validated for practical use. There remains no ‘ideal’ test or standard of care for cardiopulmonary monitoring of shock patients.

Shock has potentially reversible causes of morbidity and mortality if appropriately diagnosed and managed. Older methods of invasive monitoring have significant limitations but are still critical for managing shock in certain patients and settings. Newer methods are easier to employ, but further validation is needed. Multiple modalities along with careful clinical assessment are often useful in distinguishing shock subtypes. Best practice standards for monitoring should be based on institutional expertise.
EBM vs. EBM: combining evidence-based and experienced-based medicine in resuscitation research
Authors: Pepe Paul E. , Aufderheide Tom P.
Published: April 2017

Purpose of review

To discuss the clear rationale for evidence-based medicine (EvBM) in the challenging realms of resuscitation research, yet also provide case examples in which even the well designed, multicentered randomized clinical trial may have had unrecognized limitations, and thus misleading results. This is where experienced-based medicine (ExBM) helps to resolve the issue.

Recent findings

Recent publications have brought to task the conclusions drawn from various clinical trials of resuscitative interventions. These articles have indicated that some major clinical trials that later determined the universal guidelines for resuscitative protocols may have been affected by unrecognized confounding variables, effect modifiers and other problems such as delayed timing. Many interventions, deemed to be ineffective because of these study factors, may actually have lifesaving effects that would have been confirmed had the proper circumstances been in place. With the right mindset, the clinician-researcher can often identify and address those situations.

When clinical trials indicate ineffectiveness of an intervention that worked very well in other circumstances, both preclinical and clinical, clinician-investigators should continue to re-search the issues and not always take conclusions at face value.
Ultrasound‐guided Liver Biopsies in Children
Authors: Bilreiro Carlos , Noruegas Maria J. , Gonçalves Isabel , Moreira Ângela
Published: April 2017

Objectives:

The aim of the study was to analyze the institution's experience in ultrasound‐guided liver biopsies performed on children and identify risk factors for complications, following a previous study performed in our institution.

Methods:

Retrospective analysis of a consecutive series of ultrasound‐guided pediatric liver biopsies, between 2011 and 2016. Demographic and anthropometric data, biopsy indications, international normalized ratio (INR) and platelet count, biopsy technique, complications, and pathologic outcomes were recorded.

Results:

A total of 228 procedures were performed on 203 children with a median age of 9.25 years (range: 0.08–18.42): 107 girls (47%) and 121 boys (53%). One hundred twenty‐seven biopsies were performed on transplanted livers (55.7%) and 101 on native livers (44.3%). There were 27 cases with immediate complications (11.84%), all due to minor bleeding. There were no major complications. Increasing needle passes were shown to be a reliable predictor for bleeding (P = 0.0023), whereas transplanted livers predicted protection against bleeding (P = 0.0007). Age younger than 3 years, bodyweight <16 kg, platelet count <70 g/L and INR >1.25 revealed association with increased bleeding incidence, but no predictive value.

Conclusion:

Ultrasound‐guided liver biopsies in pediatric age are a safe procedure with a high diagnostic yield. Increasing the number of needle passes predicts a higher incidence of minor bleeding. Other factors to account for minor bleeding risk may include age younger than 3 years, bodyweight <16 kg, platelet count <70 G/L, and INR >1.25. Transplanted livers present a lower bleeding risk.
Retrospective Review of Gonococcal and Chlamydial Cases of Epididymitis at 2 Canadian Sexually Transmitted Infection Clinics, 2004–2014
Authors: Chen Justin Z , Gratrix Jennifer , Brandley Judith , Smyczek Petra , Parker Penny , Read Ron , Singh Ameeta E
Published: April 2017

Fifty-seven cases of gonococcal and chlamydial infections complicated by acute epididymitis seen at 2 Alberta STI clinics from 2004 to 2014 were reviewed. The majority responded to treatment recommended by national guidelines. Three of 6 treatment failures were not treated according to guidelines.
Impact of Eligibility Criteria on Participant Enrollment for a Randomized Clinical Trial of Gonorrhea Treatment
Authors: Long Jill E. , Wierzbicki Michael R. , Hook Edward W.
Published: April 2017

Background

High rates of failure to qualify for clinical trial participation increase time and cost required for study completion. Identification of remediable reasons for prescreen failure can help reduce prescreen failure rates and improve study cost effectiveness.

Methods

Reasons for prescreen failure to qualify for participation in a phase 2 randomized clinical trial of treatment of uncomplicated urogenital gonorrhea were collected from prescreening logs. Reasons were categorized based on whether the reason was that the subject failed to meet eligibility criteria or declined participation. Subjects who failed prescreening but could have been enrolled under protocol amendments were used to estimate potential cost savings had enrollment completed sooner.

Results

Over 88% (1373/1554) of potential study candidates were not enrolled. The majority (68.8%) of nonenrolled subjects failed prescreening due to not meeting eligibility criteria, whereas 31.0% declined to participate. The most common reasons for failure to qualify were having only nonurogenital gonorrhea (16.4%), limited time (13.1%), and being on antiretroviral therapy (7.5%). Potential cost savings if protocol amendments affecting eligibility had been instituted earlier were estimated at US $127,500.

Conclusions

Careful attention to reasons for prescreen failure can inform clinical trial protocol development to address trial design features that may impact successful enrollment. More efficient subject enrollment can result in substantial cost savings.
Chlamydia trachomatis Incidence Using Self-Reports and Serology by Gender, Age Period, and Sexual Behavior in a Birth Cohort
Authors: Righarts A. Antoinette , Morgan Jane , Horner Paddy J. , Wills Gillian S. , McClure Myra O. , Dickson Nigel P.
Published: April 2017

Background

Although understanding chlamydia incidence assists prevention and control, analyses based on diagnosed infections may distort the findings. Therefore, we determined incidence and examined risks in a birth cohort based on self-reports and serology.

Methods

Self-reported chlamydia and behavior data were collected from a cohort born in New Zealand in 1972/3 on several occasions to age 38 years. Sera drawn at ages 26, 32, and 38 years were tested for antibodies to Chlamydia trachomatis Pgp3 antigen using a recently developed assay, more sensitive in women (82.9%) than men (54.4%). Chlamydia incidence by age period (first coitus to age 26, 26–32, and 32–38 years) was calculated combining self-reports and serostatus and risk factors investigated by Poisson regression.

Results

By age 38 years, 32.7% of women and 20.9% of men had seroconverted or self-reported a diagnosis. The highest incidence rate was to age 26, 32.7 and 18.4 years per 1000 person-years for women and men, respectively. Incidence rates increased substantially with increasing number of sexual partners. After adjusting age period incidence rates for partner numbers, a relationship with age was not detected until 32 to 38 years, and then only for women.

Conclusions

Chlamydia was common in this cohort by age 38, despite the moderate incidence rates by age period. The strongest risk factor for incident infection was the number of sexual partners. Age, up to 32 years, was not an independent factor after accounting for partner numbers, and then only for women. Behavior is more important than age when considering prevention strategies.
Portrait of an Epidemic: Extremely High Human Immunodeficiency Virus Prevalence and Incidence Among Young Black Men Having Sex With Men and Residing in a Southern City
Authors: Mena Leandro , Crosby Richard A.
Published: April 2017

A 12-month prospective cohort study of 609 young black men who have sex with men (YBMSM) assessed human immunodeficiency virus seroconversion. One-hundred-seventy men (27.9%) were either human immunodeficiency virus–infected before enrollment or tested positive within 30 days afterward. Thirty (4.9%) were classified as incident infections occurring in a 12-month period. Subtracting the 170 from the denominator, incidence was 6.8%.
Help and Care Seeking for Sexually Transmitted Infections Among Youth in Low- and Middle-Income Countries
Authors: Newton-Levinson Anna , Leichliter Jami S. , Chandra-Mouli Venkatraman
Published: April 2017

Background

The ability to seek help or medical care for sexually transmitted infections (STIs) is vital for sexually active youth; yet, their needs are often unmet.

Methods

We conducted a qualitative systematic review of studies to assess youth and provider views about the behaviors of young people in help seeking and care seeking for STI services in low- and middle-income countries. We searched peer-reviewed literature for studies published between 2001 and 2014 with a study population of youth (age, 10–24 years) and/or health service providers. Eighteen studies were identified for inclusion from 18 countries. Thematic analyses identified key themes across the studies.

Results

The majority of studies included discussion of youth not seeking treatment, resorting to self-treatment, or waiting to access care, suggesting that many youth still do not seek timely care for STIs. Youth desired more information on sexual health and cited barriers related to fear or taboos in obtaining help or information, especially from providers or parents. Many did not recognize symptoms or waited until symptoms worsened. However, many youth were able to identify a number of sources for STI related care including public and private clinics, pharmacies, alternative healers, and nongovernmental organizations. Youth's help seeking and care seeking preferences were frequently influenced by desires for confidentiality, friendliness, and cost.

Conclusions

Youth in low- and middle-income countries experience significant barriers in help seeking for STIs and often do not seek or postpone medical care. Improving uptake may require efforts to address clinic systems, provider attitudes, confidentiality, and cultural norms related to youth sexuality.