Pericentrin deficiency in smooth muscle cells augments atherosclerosis through HSF1-driven cholesterol biosynthesis and PERK activation.

Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) is caused by biallelic loss-of-function variants in pericentrin (PCNT), and premature coronary artery disease (CAD) is a complication of the syndrome. Histopathology of coronary arteries from patients with MOPDII who died of CAD in their 20s showed extensive atherosclerosis. Hyperlipidemic mice with smooth muscle cell-specific (SMC-specific) Pcnt deficiency (PcntSMC-/-) exhibited significantly greater atherosclerotic plaque burden compared with similarly treated littermate controls despite similar serum lipid levels. Loss of PCNT in SMCs induced activation of heat shock factor 1 (HSF1) and consequently upregulated the expression and activity of HMG-CoA reductase (HMGCR), the rate-limiting enzyme in cholesterol biosynthesis. The increased cholesterol biosynthesis in PcntSMC-/- SMCs augmented PERK signaling and phenotypic modulation compared with control SMCs. Treatment with the HMGCR inhibitor, pravastatin, blocked the augmented SMC modulation and reduced plaque burden in hyperlipidemic PcntSMC-/- mice to that of control mice. These data support the notion that Pcnt deficiency activates cellular stress to increase SMC modulation and plaque burden, and targeting this pathway with statins in patients with MOPDII has the potential to reduce CAD in these individuals. The molecular mechanism uncovered further emphasizes SMC cytosolic stress and HSF1 activation as a pathway driving atherosclerotic plaque formation independently of cholesterol levels.

Sexual Dimorphism in the Extracellular and Pericellular Matrix of Articular Cartilage.

OBJECTIVE: Women have a higher prevalence and burden of joint injuries and pathologies involving articular cartilage than men. Although knee injuries affecting young women are on the rise, most studies related to sexual dimorphism target postmenopausal women. We hypothesize that sexual dimorphism in cartilage structure and mechanics is present before menopause, which can contribute to sex disparities in cartilage pathologies. DESIGN: Bovine knee was used as a model to study healthy adult cartilage. We compared elastic moduli under compression, abundances of extracellular and pericellular matrix (PCM) proteins using proteomics, and PCM constituency with tissue immunofluorescence. The gene expression of matrix-related genes under basal, anabolic, and catabolic conditions was assessed by quantitative polymerase chain reaction (qPCR). RESULTS: The equilibrium modulus was higher in male cartilage compared with female cartilage. Proteoglycans were not associated with this biomechanical dimorphism. Proteomic and pathway analyses of tissue showed dimorphic enriched pathways in extracellular matrix (ECM)-related proteins in which male cartilage was enriched in matrix interconnectors and crosslinkers that strengthen the ECM network. Moreover, male and female tissue differed in enriched PCM components. Females had more abundance of collagen type VI and decorin, suggesting different PCM mechanics. Furthermore, the activation of regenerative and catabolic function in chondrocytes triggered sex-dependent signatures in gene expression, indicating dimorphic genetic regulation that is dependent on stimulation. CONCLUSIONS: We provide evidence for sexual dimorphism in cartilage before menopause. Some differences are intrinsic to chondrocytes' gene expression defined by their XX versus XY chromosomal constituency.

Bioresorbable Stent to Manage Congenital Heart Defects in Children.

Intravascular stents for pediatric patients that degrade without inhibiting vessel growth remain a clinical challenge. Here, poly(L-lactide) fibers (DH-BDS) at two thicknesses, 250 µm and 300 µm, were assembled into large, pediatric-sized stents (Ø10 - Ø20 mm). Fibers were characterized mechanically and thermally, then stent mechanical properties were compared to metal controls, while mass loss and degradation kinetics modeling estimated total stent degradation time. Thicker fibers displayed lower stiffness (1969 ± 44 vs 2126 ± 37 MPa) and yield stress (117 ± 12 vs 137 ± 5 MPa) than thinner counterparts, but exhibited similar fail strength (478 ± 28 vs 476 ± 16 MPa) at higher strains (47 ± 2 vs 44 ± 2%). Stents all exhibited crystallinity between 51.3 - 54.4% and fiber glass transition temperatures of 88.6 ± 0.5 °C and 84.6 ± 0.5 °C were well above physiological ranges. Radial strength (0.31 ± 0.01 - 0.34 ± 0.02 N/mm) in thinner stents was similar to metal stents (0.24 - 0.41 N/mm) up to Ø14 mm with no foreshortening and thicker coils granted comparable radial strength (0.32 ± 0.02 - 0.34 ± 0.02 N/mm) in stents larger than Ø14 mm. Both 10 mm (1.17 ± 0.02 % and 0.86 ± 0.1 %) and 12 mm (1.1 ± 0.03% and 0.89 ± 0.1%) stents exhibited minimal weight loss over one year. Degradation kinetics models predicted full stent degradation within 2.8 - 4.5 years depending on thickness. DH-BDS exhibiting hoop strength similar to metal stents and demonstrating minimal degradation and strength loss over the first year before completely disappearing within 3 to 4.5 years show promise as a pediatric interventional alternative to current strategies.

A new hypothesis for the origin of Amazonian Dark Earths.

Amazonian Dark Earths (ADEs) are unusually fertile soils characterised by elevated concentrations of microscopic charcoal particles, which confer their distinctive colouration. Frequent occurrences of pre-Columbian artefacts at ADE sites led to their ubiquitous classification as Anthrosols (soils of anthropic origin). However, it remains unclear how indigenous peoples created areas of high fertility in one of the most nutrient-impoverished environments on Earth. Here, we report new data from a well-studied ADE site in the Brazilian Amazon, which compel us to reconsider its anthropic origin. The amounts of phosphorus and calcium-two of the least abundant macronutrients in the region-are orders of magnitude higher in ADE profiles than in the surrounding soil. The elevated levels of phosphorus and calcium, which are often interpreted as evidence of human activity at other sites, correlate spatially with trace elements that indicate exogenous mineral sources rather than in situ deposition. Stable isotope ratios of neodymium, strontium, and radiocarbon activity of microcharcoal particles also indicate exogenous inputs from alluvial deposition of carbon and mineral elements to ADE profiles,  beginning several thousands of years before the earliest evidence of soil management for plant cultivation in the region. Our data suggest that indigenous peoples harnessed natural processes of landscape formation, which led to the unique properties of ADEs, but were not responsible for their genesis. If corroborated elsewhere, this hypothesis would transform our understanding of human influence in Amazonia, opening new frontiers for the sustainable use of tropical landscapes going forward.

Sixteen hundred years of increasing tree cover prior to modern deforestation in Southern Amazon and Central Brazilian savannas.

Tropical ecosystems are under increasing pressure from land-use change and deforestation. Changes in tropical forest cover are expected to affect carbon and water cycling with important implications for climatic stability at global scales. A major roadblock for predicting how tropical deforestation affects climate is the lack of baseline conditions (i.e., prior to human disturbance) of forest-savanna dynamics. To address this limitation, we developed a long-term analysis of forest and savanna distribution across the Amazon-Cerrado transition of central Brazil. We used soil organic carbon isotope ratios as a proxy for changes in woody vegetation cover over time in response to fluctuations in precipitation inferred from speleothem oxygen and strontium stable isotope records. Based on stable isotope signatures and radiocarbon activity of organic matter in soil profiles, we quantified the magnitude and direction of changes in forest and savanna ecosystem cover. Using changes in tree cover measured in 83 different locations for forests and savannas, we developed interpolation maps to assess the coherence of regional changes in vegetation. Our analysis reveals a broad pattern of woody vegetation expansion into savannas and densification within forests and savannas for at least the past ~1,600 years. The rates of vegetation change varied significantly among sampling locations possibly due to variation in local environmental factors that constrain primary productivity. The few instances in which tree cover declined (7.7% of all sampled profiles) were associated with savannas under dry conditions. Our results suggest a regional increase in moisture and expansion of woody vegetation prior to modern deforestation, which could help inform conservation and management efforts for climate change mitigation. We discuss the possible mechanisms driving forest expansion and densification of savannas directly (i.e., increasing precipitation) and indirectly (e.g., decreasing disturbance) and suggest future research directions that have the potential to improve climate and ecosystem models.

Three-dimensional printing of poly(glycerol sebacate fumarate) gadodiamide-poly(ethylene glycol) diacrylate structures and characterization of mechanical properties for soft tissue applications.

Bioresorbable materials have been frequently used to three-dimensional (3D) print biomedical structures. In this study, we developed a technique to 3D print poly(glycerol sebacate fumarate) gadodiamide (Rylar)-poly(ethylene glycol) diacrylate (PEGDA) samples and investigated their mechanical and thermal properties as a function of (PS) and ultraviolet intensity (UVI). The Young's modulus (E), ultimate tensile strength (UTS), failure strain (ɛF ), and glass transition temperature (Tg ) showed strong correlation with PS and UVI. Results showed E to be between 1.31 and 3.12 MPa, UTS between 0.07 and 0.43 MPa, and ɛF between 7 and 20% with brittle failure. The Tg was observed to lie between -54.48 and -49.10 °C without secondary/tertiary transitions. Dominant elastic behavior was observed from the dynamic mechanical testing viscoelastic data. Testing results were used to develop a regression predictive model for E as a function of PS and UVI. The model performance was evaluated experimentally with an average absolute error of 3.62%. The E and stress-strain response of our 3D printed samples show agreement with published data for human tracheal cartilage, and the mechanical properties were comparable to other published soft polymeric scaffolds/patches. The E' moduli were also similar to bovine articular cartilage. We have successfully demonstrated that Rylar, a novel bioresorbable radiopaque polymer, when blended with PEGDA can be 3D printed controllably for soft tissue applications such as airway obstructions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 664-671, 2019.

Development and validation of a full model of a four-headed neuroimaging single-photon emission computed tomography scanner.

OBJECTIVE: The Nucline X-Ring 4R is a four-headed gamma camera dedicated to neuroimaging. In this paper, we describe and validate a GATE (Geant4 Application for Tomographic Emission) model of the Nucline X-Ring 4R. MATERIALS AND METHODS: Images produced during model simulations were compared with those acquired experimentally to confirm the model was an accurate representation of the scanner. The most commonly reported measurements used to validate a GATE model include energy resolution, spatial resolution and sensitivity. In addition to the commonly reported static imaging measures, single-photon emission computed tomography (SPECT) spatial resolution was investigated to confirm that the model produces similar SPECT images to the experimental output. RESULTS: The experimental full-width at half-maximum was calculated to be 12.3 keV, which corresponds to an energy resolution of 8.8%. The simulated full-width at half-maximum was measured to be 12 keV, giving an energy resolution of 8.6%. The average spatial resolutions were found to be well matched (5.69 mm - simulated and 5.64 mm - experimental). However, the sensitivity was overestimated using the GATE model (47.8 and 54.3 cps/MBq) compared with the values obtained experimentally (42.7 and 44.3 cps/MBq). Finally, the simulated SPECT spatial resolution images were found to produce qualitatively comparable results. CONCLUSION: The model developed has been shown to produce similar results and images to those obtained experimentally. This model has the potential to simulate patient scans with the aim of improving patient care by optimizing scanner protocols.

Severe Burn-Induced Inflammation and Remodeling of Achilles Tendon in a Rat Model.

Severe burn causes systemic inflammation and hypercatabolism, resulting in damage to multiple organs distant to the burn site, including the musculoskeletal system. Bone mass and muscle loss have been reported. However, tendon that connects bone and muscle has not been studied in comparable detail. Here we aimed to characterize the molecular and functional changes in Achilles tendon triggered by severe burn. Forty male Sprague-Dawley rats received 40% total body surface area scald burn. Achilles tendons were collected up to 14 days postburn. Sham-treated animals served as a control group. We analyzed tendons for changes in expression of IL-6, IL-1ß, TNF, MMP9, MMP13, TGFß1, Collagens I and III, and for morphological and biomechanical changes. Gene expression of IL-6 and IL-1ß as well as MMP9 and MMP13 increased in rat tendon 3 days after burn. Col3a1 increased at day 3 and col1a1 at day 7. At day 14, TGFß1 increased, whereas the protein ratio for collagens I/III decreased, indicating tendon remodeling. Histological analysis with H&E and Picrosirius red staining further revealed a decrease in organized collagen fibers 14 days after burn. Biomechanical analysis showed a decrease in stiffness and ultimate force of tendons in burn rats.We conclude that tendinopathy was observed in Achilles tendon 14 days after severe burn, via the induction of inflammation and remodeling. The present study provides a model of tendinopathy that may be used for the development of therapeutic approaches after burn.

Pediatric Needle Cricothyrotomy: A Case for Simulation in Prehospital Medicine.

INTRODUCTION: A patient that cannot be oxygenated or ventilated requires immediate and effective assessment, treatment, and transportation. Pediatric needle cricothyrotomy is used infrequently, therefore providers have a tendency to lose proficiency. Simulation training and evaluation are valuable tools to improve provider experience and skill. METHODS: A case was designed involving a 3-year-old male with a peanut allergy that presents with rash, swelling, and severe respiratory distress. The patient's respiratory distress and swelling worsens despite treatment with epinephrine and other allergic reaction medications. The patient then becomes unresponsive and impossible to oxygenate or ventilate. The primary objective of this case is airway management with needle cricothyrotomy in the pediatric population. A secondary objective is appropriate postprocedure management including appropriate ventilation rates and emergency medical transportation methods. RESULTS: This case was initially presented to 45 paramedics. Provider comfort with managing airway emergencies in young children improved from 47% to 89%. Confidence in performing pediatric needle cricothyrotomy improved from 16% to 87%. All providers felt the exercise was valuable and 98% felt the simulation provided appropriate realism. DISCUSSION: This scenario provides an outstanding opportunity for paramedic evaluation and training in pediatric needle cricothyrotomy and significantly improved the comfort level of providers' management of a failed pediatric airway. As we reflected on the use of this module, it was apparent that this was a very beneficial opportunity to spend one-on-one time between participants and their medical director. The training staff also benefited from the repeated emphasis of good assessment and treatment of a complex patient scenario.

Brain Tumor Genetic Modification Yields Increased Resistance to Paclitaxel in Physical Confinement.

Brain tumor cells remain highly resistant to radiation and chemotherapy, particularly malignant and secondary cancers. In this study, we utilized microchannel devices to examine the effect of a confined environment on the viability and drug resistance of the following brain cancer cell lines: primary cancers (glioblastoma multiforme and neuroblastoma), human brain cancer cell lines (D54 and D54-EGFRvIII), and genetically modified mouse astrocytes (wild type, p53-/-, p53-/- PTEN-/-, p53-/- Braf, and p53-/- PTEN-/- Braf). We found that loss of PTEN combined with Braf activation resulted in higher viability in narrow microchannels. In addition, Braf conferred increased resistance to the microtubule-stabilizing drug Taxol in narrow confinement. Similarly, survival of D54-EGFRvIII cells was unaffected following treatment with Taxol, whereas the viability of D54 cells was reduced by 75% under these conditions. Taken together, our data suggests key targets for anticancer drugs based on cellular genotypes and their specific survival phenotypes during confined migration.

Allele-specific knockdown of ALS-associated mutant TDP-43 in neural stem cells derived from induced pluripotent stem cells.

TDP-43 is found in cytoplasmic inclusions in 95% of amyotrophic lateral sclerosis (ALS) and 60% of frontotemporal lobar degeneration (FTLD). Approximately 4% of familial ALS is caused by mutations in TDP-43. The majority of these mutations are found in the glycine-rich domain, including the variant M337V, which is one of the most common mutations in TDP-43. In order to investigate the use of allele-specific RNA interference (RNAi) as a potential therapeutic tool, we designed and screened a set of siRNAs that specifically target TDP-43(M337V) mutation. Two siRNA specifically silenced the M337V mutation in HEK293T cells transfected with GFP-TDP-43(wt) or GFP-TDP-43(M337V) or TDP-43 C-terminal fragments counterparts. C-terminal TDP-43 transfected cells show an increase of cytosolic inclusions, which are decreased after allele-specific siRNA in M337V cells. We then investigated the effects of one of these allele-specific siRNAs in induced pluripotent stem cells (iPSCs) derived from an ALS patient carrying the M337V mutation. These lines showed a two-fold increase in cytosolic TDP-43 compared to the control. Following transfection with the allele-specific siRNA, cytosolic TDP-43 was reduced by 30% compared to cells transfected with a scrambled siRNA. We conclude that RNA interference can be used to selectively target the TDP-43(M337V) allele in mammalian and patient cells, thus demonstrating the potential for using RNA interference as a therapeutic tool for ALS.

KDM4B is a master regulator of the estrogen receptor signalling cascade.

The importance of the estrogen receptor (ER) in breast cancer (BCa) development makes it a prominent target for therapy. Current treatments, however, have limited effectiveness, and hence the definition of new therapeutic targets is vital. The ER is a member of the nuclear hormone receptor superfamily of transcription factors that requires co-regulator proteins for complete regulation. Emerging evidence has implicated a small number of histone methyltransferase (HMT) and histone demethylase (HDM) enzymes as regulators of ER signalling, including the histone H3 lysine 9 tri-/di-methyl HDM enzyme KDM4B. Two recent independent reports have demonstrated that KDM4B is required for ER-mediated transcription and depletion of the enzyme attenuates BCa growth in vitro and in vivo. Here we show that KDM4B has an overarching regulatory role in the ER signalling cascade by controlling expression of the ER and FOXA1 genes, two critical components for maintenance of the estrogen-dependent phenotype. KDM4B interacts with the transcription factor GATA-3 in BCa cell lines and directly co-activates GATA-3 activity in reporter-based experiments. Moreover, we reveal that KDM4B recruitment and demethylation of repressive H3K9me3 marks within upstream regulatory regions of the ER gene permits binding of GATA-3 to drive receptor expression. Ultimately, our findings confirm the importance of KDM4B within the ER signalling cascade and as a potential therapeutic target for BCa treatment.

The C9ORF72 expansion mutation is a common cause of ALS+/-FTD in Europe and has a single founder.

A massive hexanucleotide repeat expansion mutation (HREM) in C9ORF72 has recently been linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we describe the frequency, origin and stability of this mutation in ALS+/-FTD from five European cohorts (total n=1347). Single-nucleotide polymorphisms defining the risk haplotype in linked kindreds were genotyped in cases (n=434) and controls (n=856). Haplotypes were analysed using PLINK and aged using DMLE+. In a London clinic cohort, the HREM was the most common mutation in familial ALS+/-FTD: C9ORF72 29/112 (26%), SOD1 27/112 (24%), TARDBP 1/112 (1%) and FUS 4/112 (4%) and detected in 13/216 (6%) of unselected sporadic ALS cases but was rare in controls (3/856, 0.3%). HREM prevalence was high for familial ALS+/-FTD throughout Europe: Belgium 19/22 (86%), Sweden 30/41 (73%), the Netherlands 10/27 (37%) and Italy 4/20 (20%). The HREM did not affect the age at onset or survival of ALS patients. Haplotype analysis identified a common founder in all 137 HREM carriers that arose around 6300 years ago. The haplotype from which the HREM arose is intrinsically unstable with an increased number of repeats (average 8, compared with 2 for controls, P<10(-8)). We conclude that the HREM has a single founder and is the most common mutation in familial and sporadic ALS in Europe.

Effects of known phenoloxidase inhibitors on hemocyanin-derived phenoloxidase from Limulus polyphemus.

Inhibitors of phenoloxidase are used routinely to characterise the structural and functional properties of phenoloxidases. Hemocyanin-derived phenoloxidase activity is also sensitive to standard phenoloxidase inhibitors. In this study, we characterise the effects of a number of phenoloxidase inhibitors on hemocyanin-derived phenoloxidase activity from the chelicerate, Limulus polyphemus. Both inhibition type and K(i) values were similar to those observed for hemocyanin-derived phenoloxidase from another chelicerate, Eurypelma californicum. In addition, substrate inhibition was observed at concentrations above 2mM dopamine. The conformation in which two of the inhibitors, namely tropolone and kojic acid, would bind near the Cu(II) centre of hemocyanin is proposed.

Biphasic investigation of tissue mechanical response during freezing front propagation.

Cryopreservation of engineered tissue (ET) has achieved limited success due to limited understanding of freezing-induced biophysical phenomena in ETs, especially fluid-matrix interaction within ETs. To further our understanding of the freezing-induced fluid-matrix interaction, we have developed a biphasic model formulation that simulates the transient heat transfer and volumetric expansion during freezing, its resulting fluid movement in the ET, elastic deformation of the solid matrix, and the corresponding pressure redistribution within. Treated as a biphasic material, the ET consists of a porous solid matrix fully saturated with interstitial fluid. Temperature-dependent material properties were employed, and phase change was included by incorporating the latent heat of phase change into an effective specific heat term. Model-predicted temperature distribution, the location of the moving freezing front, and the ET deformation rates through the time course compare reasonably well with experiments reported previously. Results from our theoretical model show that behind the marching freezing front, the ET undergoes expansion due to phase change of its fluid contents. It compresses the region preceding the freezing front leading to its fluid expulsion and reduced regional fluid volume fractions. The expelled fluid is forced forward and upward into the region further ahead of the compression zone causing a secondary expansion zone, which then compresses the region further downstream with much reduced intensity. Overall, it forms an alternating expansion-compression pattern, which moves with the marching freezing front. The present biphasic model helps us to gain insights into some facets of the freezing process and cryopreservation treatment that could not be gleaned experimentally. Its resulting understanding will ultimately be useful to design and improve cryopreservation protocols for ETs.

Auditory memory distortion for spoken prose.

Observers often remember a scene as containing information that was not presented but that would have likely been located just beyond the observed boundaries of the scene. This effect is called boundary extension (BE; e.g., Intraub & Richardson, 1989). Previous studies have observed BE in memory for visual and haptic stimuli, and the present experiments examined whether BE occurred in memory for auditory stimuli (prose, music). Experiments 1 and 2 varied the amount of auditory content to be remembered. BE was not observed, but when auditory targets contained more content, boundary restriction (BR) occurred. Experiment 3 presented auditory stimuli with less content and BR also occurred. In Experiment 4, white noise was added to stimuli with less content to equalize the durations of auditory stimuli, and BR still occurred. Experiments 5 and 6 presented trained stories and popular music, and BR still occurred. This latter finding ruled out the hypothesis that the lack of BE in Experiments 1-4 reflected a lack of familiarity with the stimuli. Overall, memory for auditory content exhibited BR rather than BE, and this pattern was stronger if auditory stimuli contained more content. Implications for the understanding of general perceptual processing and directions for future research are discussed.

Breast cancer resistance protein BCRP (ABCG2)-mediated transepithelial nitrofurantoin secretion and its regulation in human intestinal epithelial (Caco-2) layers.

In order to determine the capacity and regulation of the breast cancer resistance protein (BCRP)-mediated transport in intact human intestinal epithelial monolayers (Caco-2) in which multiple ABC transporters are expressed, nitrofurantoin has been used as a selective transported substrate. Nitrofurantoin transepithelial secretion was confirmed in both human BCRP and mouse bcrp-transfected MDCKII epithelia, whereas no net transepithelial secretion was observed in native or human MDR1-MDCKII epithelia. Furthermore, nitrofurantoin transepithelial secretion by BCRP-MDCKII monolayers was inhibited by Ko143 (10 µM), but not verapamil (100 µM). In Caco-2 cells grown upon permeable supports, nitrofurantoin displayed a dose-dependent transepithelial secretion with an apparent Km=69.41 ± 22.3 µM and Vmax=14.03 ± 2.27 nmol/(cm(2).h). Net nitrofurantoin transepithelial secretion by Caco-2 epithelia was inhibited 92% by 10 µM Ko143. Regulation of expression and function of BCRP in Caco-2 epithelial monolayers was determined after 72-h pre-exposure of the monolayers to a number of potential inducing agents. Quantitative real-time PCR and Western blotting were used to correlate induction of BCRP transcript and protein levels with transport activity. 72-h pre-treatment with ß-napthoflavone and rosiglitazone up-regulates BCRP mRNA and protein expression and transport of nitrofurantoin. Ko143-sensitive transepithelial secretion of the bi-substrate (MDR1/BCRP) prazosin was also increased in the presence of rosiglitazone. We conclude that nitrofurantoin may be used to unambiguously measure BCRP-mediated fluxes in Caco-2 epithelial layers. Since dynamic regulation of BCRP expression and function is retained, the Caco-2 cell-line is useful as a screen for drug-drug and drug-diet interactions mediated by BCRP.

The Canadian StoneBreaker trial: a randomized, multicenter trial comparing the LMA StoneBreaker™ and the Swiss LithoClast® during percutaneous nephrolithotripsy.

BACKGROUND AND PURPOSE: Percutaneous nephrolithotripsy (PCNL) is the treatment of choice for patients with large renal stones. The StoneBreaker™ (SB) is a novel handheld pneumatic lithotriptor, powered by a compressed carbon dioxide cartridge. The purpose of this study was to compare the efficiency of the SB to a standard pneumatic lithotriptor, the Swiss LithoClast(®) (LC). PATIENTS AND METHODS: From January 2008 to December 2009, patients undergoing PCNL were randomized to either the SB or the Swiss LC. Primary outcomes included time to fragment the stone, retrieve the fragments, and remove debris using ultrasonic lithotripsy. Secondary end points were stone-free rate, lithotriptor setup time, ease of use, operator fatigue, endoscopic visualization, damage to mucosa, and device-related complications. RESULTS: Of the initial 115 patients recruited, 77 were enrolled and 38 were excluded. The SB had significantly faster stone fragmentation time, total lithotripsy time, and setup time than the Swiss LC (P ≤ 0.05). A significant difference was also noted in the ease of use and operator fatigue in favor of the SB. There were no device-related complications. CONCLUSION: The SB pneumatic lithotriptor is easier to set up and use, and it provides faster stone fragmentation than the Swiss LC.