Volume Preservation Research Articles

Mastopexy using de-epithelialised dermoglandular flaps: a case series for maximal volume conservation following breast implants removal

Aims and objectiveRemoval of implants without replacement is often requested, and the procedure is more commonly performed today than ever before. However, the resultant loss of body image, secondary to the loss of breast volume, is not an outcome, that a patient is looking forward to. There is a lack of information on the options available to the patients following explantation. This case series presents an option of breast volume preservation and reshaping during mastopexy after breast implant removal that can be offered to selected patients. In the current case series, de-epithelialised dermoglandular flap mastopexy was used as an autologous tissue for breast reshaping and remodelling.Material and methodsSince 2015, ten patients were selected for de-epithelialised dermoglandular mastopexy using wise pattern or vertical scar. Surgery was performed under general anaesthesia as a day case. A vertically oriented bipedicular dermoglandular flap was used for vertical scar mastopexy in two patients, and eight patients had Wise pattern incisions. Of these eight patients, four had superomedial and four had inferiorly based flaps for dermoglandular mastopexy and closure. All patients had a preoperative cup size D or larger.ResultsAll patients had adequate results with an acceptable breast cup size. There was no skin breakdown, nipple loss, haematoma or infection.ConclusionDe-epithelialised dermoglandular flap mastopexy is a safe procedure and can be used as an option in selected patients.Level of EvidenceIV.

Computed Tomography-Guided Localization and Extended Segmentectomy for Non-Small Cell Lung Cancer.

Background: Lung cancer is one of the most devastating cancers. Low-dose computed tomography (LDCT) can detect lung cancer at an early stage of the disease when a minimally invasive surgical procedure using video-assisted thoracoscopic surgery is the best strategy. Herein, we discuss the treatment of deep lung tumors between segments or lesions located near the margin of a segment. Patients and Methods: This was a retrospective study conducted from January 2013 to January 2020 using the National Taiwan University Hospital data bank. We included early-stage non-small cell lung cancer (NSCLC) patients who underwent lung surgery and screened out those who received CT-guided localization for extended segmentectomy. Outcome measurements were safety margin, complication rate, and postoperative course. Results: During the study period, 68 patients with early-stage NSCLC received CT-guided localization followed by extended segmentectomy. The mean surgery time was 92.1 ± 30.3 min, and the mean blood loss was 32.8 mL. Mean drainage time was 2.3 ± 1 days, and the total hospital stay was 4.9 ± 1.1 days. Pathological reports showed tumor-free resection margins >2 cm. Sixty-one patients had adenocarcinoma at stage IA and two patients at stage IB. One patient had squamous cell carcinoma at stage IA. Conclusion: CT-guided localization followed by extended segmentectomy allows lung volume preservation with clean safety margins and good clinical outcomes.

POSTINJURY FECAL MICROBIOME TRANSPLANT DECREASES LESION SIZE AND NEUROINFLAMMATION IN TRAUMATIC BRAIN INJURY.

Background: Traumatic brain injury (TBI) is an underrecognized public health threat. The constitutive activation of microglia after TBI has been linked to long-term neurocognitive deficits and the progression of neurodegenerative disease. Evolving evidence indicates a critical role for the gut-brain axis in this process. Specifically, TBI has been shown to induce the depletion of commensal gut bacteria. The resulting gut dysbiosis is associated with neuroinflammation and disease. Hypothesis: We hypothesized that fecal microbiota transplantation would attenuate microglial activation and improve neuropathology after TBI. Methods: C57Bl/6 mice were subjected to severe TBI (n = 10) or sham injury (n = 10) via an open-head controlled cortical impact. The mice underwent fecal microbiota transplantation (FMT) or vehicle alone via oral gavage once weekly for 4 weeks after injury. At 59 days after TBI, mice underwent three-dimensional, contrast-enhanced magnetic resonance imaging. Following imaging, mice were killed, brains harvested at 60 DPI, and CD45+ cells isolated via florescence-activated cell sorting. cDNA libraries were prepared using the 10x Genomics Chromium Single Cell 3' Reagent kit followed by sequencing on a HiSeq4000 instrument, and computational analysis was performed. Results: Fecal microbiota transplantation resulted in a >marked reduction of ventriculomegaly (P < 0.002) and preservation of white matter connectivity at 59 days after TBI (P < 0.0001). In addition, microglia from FMT-treated mice significantly reduced inflammatory gene expression and enriched pathways involving the heat-shock response compared with mice treated with vehicle alone. Conclusions: We hypothesized that restoring gut microbial community structure via FMT would attenuate microglial activation and reduce neuropathology after TBI. Our data demonstrated significant preservation of cortical volume and white matter connectivity after an injury compared with mice treated with vehicle alone. This preservation of neuroanatomy after TBI was associated with a marked reduction in inflammatory gene expression within the microglia of FMT-treated mice. Microglia from FMT-treated mice enriched pathways in the heat-shock response, which is known to play a neuroprotective role in TBI and other neurodegenerative disease processes.

Objective Physical Activity Accumulation and Brain Volume in Older Adults: An MRI and Whole-Brain Volume Study.

A decrease in brain volume (ie, brain atrophy) is a marker of cognitive health in older adults. Insufficient weekly accumulation of moderate and vigorous physical activity (MVPA) has been associated with lower brain volume. As this association has been established for a small number of brain areas and structures and atrophy rates seem to be nonuniform between them, more comprehensive analyses are warranted. We compared the volume of 71 brain areas and structures in 45 older adults who met and did not meet objectively measured MVPA recommendations. In addition, we used multiple regression models to determine whether cardiorespiratory fitness (VO2PEAK), MVPA, and health-related risk factors could affect the atrophy of brain areas and structures. An accelerometer (GT9-X ActiGraph) was worn for 7days. Participants were then classified into 2 groups: <150 minutes MVPA (<150'MVPA; n=20) and ≥150 minutes MVPA (≥150'MVPA; n=25) per week. Older adults who accumulated ≥150'MVPA per week had significantly higher absolute and relative (%of intracranial volume) volumes of 39 and 9 brain areas and structures, respectively, than those who accumulated <150'MVPA per week. Higher VO2PEAK seems to be a key predictor of the atrophy of brain areas and structures. In conclusion, meeting weekly physical activity recommendations seems to have a widespread effect on preserving the volume of more than 30 brain areas and structures in older adults. VO2PEAK seems to be the most frequent and important predictor of brain volume preservation.

Molecular, cellular and surgical processes of osseointegration for dental implants: a systematic review

Introduction: The maxillary sinus floor elevation procedure should be performed based on the cellular and molecular process of osseointegration. In this sense, when grafting procedures are necessary, the success and predictability of the results do not depend only on the biomaterial, but as well as the morphology of the bone defect. Combinations have been proposed to obtain better regenerative conditions through volume preservation (osteoconduction) and induction of cell migration differentiation (osteoinduction). The surface microstructure of Bio Oss® supports the growth of osteoblasts, which are responsible for bone formation. Objective: To carry out a concise systematic review of the molecular and surgical processes of osseointegration for dental implants. Methods: The present study was followed by a systematic review model (PRSMA). The search strategy was performed in the PubMed, Cochrane Library, Web of Science and Scopus, and Google Scholar databases. The Cochrane Instrument was used to assess the risk of bias from the included studies. Results and Conclusion: In line with the objective of this study, it was observed that the understanding of bone bioengineering, understanding the entire bioprocess of bone formation through the main cells (mesenchymal stem cells and osteoblasts) and molecules (BMPs, PRP, PRF, cytokines and growth factors), can promote the use of biomaterials and epithelial barriers that help in the treatment as an adjuvant to bone grafting-techniques, favoring greater predictability in alveolar and peri-implant reconstructions and with a good prognosis.

Analysis of wound discharge microbiota in patients with drug-associated osteonecrosis of the jaw

Introduction. Chronic forms of inflammatory periodontal diseases, leading to deterioration of bone tissue quality and volume, are the most important and urgent problems for modern dentistry. Despite the measures taken at different levels of prevention the tendency to the increase of patients with periodontitis has been revealed. The aim of the investigation was to make a comparative clinical and radiological evaluation of the effectiveness of directed tissue regeneration (DTR) using different methods of membrane placement in the area of defects with complex configuration in patients with moderate-to-severe chronic periodontitis. Material and methods. Patients were divided into two groups of 30 patients each. Study design: open randomized. Patients of the first group were operated on using DTR technique and additional membrane fixation by means of periodontal micropins; patients of the second group were operated on using DTR without additional membrane fixation. The results were assessed by clinical and radiological examination after 1, 3, 6 and 12 months. Results. More active regenerative processes were registered in the first group; the periodontal pocket depth after one month was 2,77 ± 0,08 mm, in patients of the second group – 2,85 ± 0,03 mm (p &lt; 0,05); the tendency for decrease of this index remained during all investigation. The Hounsfield index after 12 months was 1658 ± 45.38 units in the first group and 1589 ± 12.02 units in the second group (p &lt; 0.05). Discussion. When comparing the obtained data with those of their foreign colleagues, the authors concluded that additional fixation of the membrane leads to a less pronounced deformation and preservation of the bone volume in the long-term postoperative period. Conclusion. The use of micropins for membrane fixation allows to work with defects of complex configuration and in the long term leads to formation of denser bone tissue with preservation of its volume.

The power particle-in-cell method

This paper introduces a new weighting scheme for particle-grid transfers that generates hybrid Lagrangian/Eulerian fluid simulations with uniform particle distributions and precise volume control. At its core, our approach reformulates the construction of Power Particles [de Goes et al. 2015] by computing volume-constrained density kernels. We employ these optimized kernels as particle domains within the Generalized Interpolation Material Point method (GIMP) in order to incorporate Power Particles into the Particle-In-Cell framework, hence the name the Power Particle-In-Cell method. We address the construction of volume-constrained density kernels as a regularized optimal transportation problem and describe an iterative solver based on localized Gaussian convolutions that leads to a significant performance speedup compared to [de Goes et al. 2015]. We also present novel extensions for handling free surfaces and solid obstacles that bypass the need for cell clipping and ghost particles. We demonstrate the advantages of our transfer weights by improving hybrid schemes for fluid simulation such as the Fluid Implicit Particle (FLIP) method and the Affine Particle-In-Cell (APIC) method with volume preservation and robustness to varying particle-per-cell ratio, while retaining low numerical dissipation, conserving linear and angular momenta, and avoiding particle reseeding or post-process relaxations.

Antegrade Subperiosteal Temporalis Muscle Elevation and Posterior Retraction Technique Avoiding Muscle Incision for Pterional Craniotomy: A Technical Note.

The current technique of pterional craniotomy involves temporalis muscle incision followed by retrograde elevation. Feasibility of antegrade temporalis muscle elevation without any direct incision over its bulk is evaluated. Incisionless "antegrade, subgaleal, subfascial, and subperiosteal elevation" of temporalis muscle preserves vascularity and muscle bulk. Posterior maneuvering of "bare" temporalis muscle bulk either above (out rolling) or under (in rolling) the scalp for pterional craniotomy is discussed. Technique of antegrade, subfascial, subperiosteal elevation, and posterior rotation of temporalis muscle without incising in its bulk by "out rolling" or "in rolling" along the posterior aspect of the scalp incision was carried out in 15 cadavers and later in 50 surgical cases undergoing pterional craniotomy. Postoperatively, patients were evaluated for subgaleal collection and periorbital edema. Operated side cosmesis and temporalis muscle bulk was compared with nonoperated temporalis muscle at 6 months interval. Antegrade subperiosteal dissection of temporalis muscle was possible in all cases. "In-rolling" or "out rolling" technique provided adequate surgical exposure during pterional craniotomy. Postoperative subgaleal collection and periorbital edema was prevented. Facial nerve paresis or temporalis muscle-related complications were avoided. Antegrade, subgaleal, subfascial, and subperiosteal dissection techniques of temporalis muscle elevation without any direct incision in its bulk enables neurovascular and muscle volume preservation. Posterior maneuvering of elevated temporalis muscle with "out rolling" or "in-rolling" technique is easy, quick, and provides adequate exposure during pterional craniotomy. Opening and closing of scalp layers without violating subgaleal space prevent postoperative subgaleal hematoma and periorbital edema.

Mini-mesohepatectomy for tumours at the hepatocaval confluence: A cases series and review of the literature.

Liver lesions located adjacent to the middle hepatic vein (MHV) at the hepatocaval confluence are rare. Mini-mesohepatectomy (MMH) allows resection of these lesions with preservation of liver parenchymal volume thus reducing the risk of post-hepatectomy liver failure (PHLF). We evaluated our experience of MMH at our institution and assessed post-operative complications, disease free survival (DFS) and overall survival (OS). All patients undergoing MMH at our institution were included in the study. Intra-operative parameters, histopathological data, DFS and OS were evaluated. 11 patients with colorectal liver metastasis underwent MMH between Jan 2012 and Dec 2020. MMH resulted in R0 resection rate in all patients with no PHLF. There were 1 post-operative bile leaks but no mortality following MMH. Median DFS was 13.5 months with OS being 60 months. MMH offers safe oncological resection of lesions at the MHV at the hepatocaval confluence and should be considered in patients presenting with such lesions.

Efficient engineering of human auricular cartilage through mesenchymal stem cell chaperoning

A major challenge to the clinical translation of tissue-engineered ear scaffolds for ear reconstruction is the limited auricular chondrocyte (hAuC) yield available from patients. Starting with a relatively small number of chondrocytes in culture results in dedifferentiation and loss of phenotype with subsequent expansion. To significantly decrease the number of chondrocytes required for human elastic cartilage engineering, we co-cultured human mesenchymal stem cells (hMSCs) with HAuCs to promote healthy elastic cartilage formation. HAuCs along with human bone marrow-derived hMSCs were encapsulated into 1% Type I collagen at 25 million/mL total cell density with different ratios (HAuCs/hMSCs: 10/90, 25/75, 50/50) and then injected into customized 3D-printed polylactic acid (PLA) ridged external scaffolds, which simulate the shape of the auricular helical rim, and implanted subcutaneously in nude rats for 1, 3 and 6months. The explanted constructs demonstrated near complete volume preservation and topography maintenance of the ridged "helical" feature after 6months with all ratios. Cartilaginous appearing tissue formed within scaffolds by 3months, verified by histologic analysis demonstrating mature elastic cartilage within the constructs with chondrocytes seen in lacunae within a Type II collagen and proteoglycan-enriched matrix, and surrounded by a neoperichondrial external layer. Compressive mechanical properties comparable to human elastic cartilage were achieved after 6months. Co-implantation of hAuCs and hMSCs in collagen within an external scaffold efficiently produced shaped human elastic cartilage without volume loss even when hAuC comprised only 10% of the implanted cell population, marking a crucial step toward the clinical translation of auricular tissue engineering.

The association between long-chain polyunsaturated fatty acid intake and changes in brain volumes among older community-dwelling Japanese people

The relationship between age-related brain atrophy and long-chain polyunsaturated fatty acid (LCPUFA) intake is not fully understood. This study investigated the association of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) intake and brain atrophy in non-demented older Japanese people (n = 810, aged 60–89 years) using data sets of a 2-year longitudinal study. Brain volumes were measured using 3D-MRI in the baseline and follow-up periods. The associations of multivariate-adjusted changes in brain volumes with baseline LCPUFA intake were assessed using a general linear model. Higher ARA intake was associated with a smaller decrease in frontal cortex volumes, which was accompanied by a lower risk of cognitive decline among the participants. In the subgroup analysis for low DHA and EPA intake, accounting for one-third of Japanese intake, DHA and EPA intake was positively correlated with preservation of the temporal cortex volume. These findings suggest that appropriate intake of LCPUFA may decelerate age-related brain atrophy and lead to the maintenance of brain health in older people.

Intra-articular versus systemic vancomycin for the treatment of periprosthetic joint infection after debridement and spacer implantation in a rat model.

AimsTreatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.MethodsTotal knee arthroplasty (TKA), MRSA inoculation, debridement, and vancomycin-spacer implantation were performed successively in rats to mimic first-stage PJI during the two-stage revision arthroplasty procedure. Vancomycin was administered intraperitoneally or intra-articularly for two weeks to control the infection after debridement and spacer implantation.ResultsRats receiving intra-articular vancomycin showed the best outcomes among the four treatment groups, with negative bacterial cultures, increased weight gain, increased capacity for weightbearing activities, increased residual bone volume preservation, and reduced inflammatory reactions in the joint tissues, indicating MRSA eradication in the knee. The vancomycin-spacer and/or systemic vancomycin failed to eliminate the MRSA infections following a two-week antibiotic course. Serum vancomycin levels did not reach nephrotoxic levels in any group. Mild renal histopathological changes, without changes in serum creatinine levels, were observed in the intraperitoneal vancomycin group compared with the intra-articular vancomycin group, but no changes in hepatic structure or serum alanine aminotransferase or aspartate aminotransferase levels were observed. No local complications were observed, such as sinus tract or non-healing surgical incisions.ConclusionIntra-articular vancomycin injection was effective and safe for PJI control following debridement and spacer implantation in a rat model during two-stage revision arthroplasties, with better outcomes than systemic vancomycin administration.Cite this article: Bone Joint Res 2022;11(6):371–385.

Improving Fat Transplantation Survival and Vascularization with Adenovirus E4+ Endothelial Cell-Assisted Lipotransfer

Autologous fat transplantation is plagued by an unpredictable and often significant degree of graft loss. AdE4⁺ endothelial cells (ECs) are human endothelial cells that have been transduced with the E4ORF1 region of human adenovirus type 5, resulting in long-term preservation of EC proliferation and angiogenic capability without immortalization. We hypothesized that AdE4⁺ EC-enriched fat grafts would demonstrate improved volume retention secondary to enhanced angiogenesis. Three experimental groups were prepared by admixing 400 µL of patient lipoaspirate with 100 µL of AdE4⁺ EC suspensions (high AdE4⁺ EC concentration-enriched [5 × 10⁶/mL], low AdE4⁺ EC concentration-enriched [1.25 × 10⁶/mL], or PBS) and injected subcutaneously into the bilateral dorsa of nude mice. Fat transplants were explanted at 90 and 180 days for volumetric and histologic analyses. After both 90 and 180 days, AdE4⁺ EC-enriched fat grafts showed greater mean volume preservation compared to control grafts (p < 0.05). Regions of focal necrosis were only noticed in low AdE4⁺ EC concentration-enriched and control groups after 180 days. Histologic analysis demonstrated the presence of healthy adipocytes in all AdE4⁺ EC-enriched fat grafts in which both human and host ECs were evident after 90 and 180 days. AdE4⁺ EC enrichment improved fat graft volume preservation and vascularization in this murine xenograft model. Though further study is warranted, AdE4⁺ ECs demonstrated to be promising as a potential off-the-shelf adjunct for improving the volume, quality, and consistency of fat engraftment.

Investigation of the main clinical findings of maxillary sinus surgery with platelet-rich fibrin: a systematic review

Introduction: The maxillary sinus is the largest of the paranasal sinuses and its function is to contribute to phonation resonance, conditioning the air we breathe and aiding in the production of mucus in the nasal cavity. Around 25% of all maxillary sinuses, there is an accessory bone that is located in a lower portion than the main ostium. Aiming to increase the bone formation potential of these grafts, combinations have been proposed to obtain better regenerative conditions through volume preservation and induction of cell migration differentiation. Objective: Conducted a systematic review of the main clinical findings of maxillary sinus surgery using Platelet-rich fibrin. Methods: The present study followed a systematic review model (PRISMA). Experimental and clinical studies were selected, involving retrospective, prospective and randomized studies. The online databases consulted were PubMed, Scopus, Ovid, Periodicos.com, and Google Scholar. Results and Conclusion: A total of 59 articles were found involving the surgery of the maxillary sinuses using plasma rich in fibrin. A total of 34 articles were fully evaluated and 24 were included and discussed in this study. Studies have shown that PRF has the characteristic of polymerizing. The incorporation of circulating cytokines increases in the fibrin network, implying a longer life for these cytokines, as they will be released and used only in the remodeling of the initial scar matrix, which is long-term. PRF is based on protecting growth factors from proteolysis that can maintain their activity for a longer period and stimulate bone regeneration more efficiently. Another study indicated the use of fibrin membranes obtained from PRF to seal the perforations. In the presence of perforations larger than 10.0 mm, the surgery must be aborted and re-entry performed after 60 to 90 days. Furthermore, the combination of biomaterial and PRF significantly improved bone regeneration in the peri-implant area. Therefore, although the results do not seem to confirm that PRF is better than other biomaterials, it is suggested that its use can result in a decrease in the total healing time, around 104 days, and improve the handling of the graft material.

A shape design problem for the Navier–Stokes flow with a convective boundary condition

In this study, a shape optimization problem for the two-dimensional stationary Navier–Stokes equations with an artificial boundary condition is considered. The fluid is assumed to be flowing through a rectangular channel, and the artificial boundary condition is formulated so as to take into account the possibility of ill-posedness caused by the usual do-nothing boundary condition. The goal of the optimization problem is to maximize the vorticity of the said fluid by determining the shape of an obstacle inside the channel. Meanwhile, the shape variation is limited by a perimeter functional and a volume constraint. The perimeter functional was considered to act as a Tikhonov regularizer and the volume constraint is added to exempt us from possible topological changes. The shape derivative of the objective functional was formulated using the rearrangement method, and this derivative was later on used for gradient descent methods. Additionally, an augmented Lagrangian method and a class of solenoidal deformation fields were considered to take into account the goal of volume preservation. Lastly, numerical examples based on gradient descent and the volume preservation methods are presented.

Quantification of vascular networks in photoacoustic mesoscopy

Mesoscopic photoacoustic imaging (PAI) enables non-invasive visualisation of tumour vasculature. The visual or semi-quantitative 2D measurements typically applied to mesoscopic PAI data fail to capture the 3D vessel network complexity and lack robust ground truths for assessment of accuracy. Here, we developed a pipeline for quantifying 3D vascular networks captured using mesoscopic PAI and tested the preservation of blood volume and network structure with topological data analysis. Ground truth data of in silico synthetic vasculatures and a string phantom indicated that learning-based segmentation best preserves vessel diameter and blood volume at depth, while rule-based segmentation with vesselness image filtering accurately preserved network structure in superficial vessels. Segmentation of vessels in breast cancer patient-derived xenografts (PDXs) compared favourably to ex vivo immunohistochemistry. Furthermore, our findings underscore the importance of validating segmentation methods when applying mesoscopic PAI as a tool to evaluate vascular networks in vivo.

Volume preservation of a shattered kidney after blunt trauma by superselective renal artery embolization.

PURPOSE We examined whether superselective embolization of the renal artery could be effectively employed to preserve traumatic kidneys and assessed its clinical outcomes. METHODS Between December 2015 and November 2019, 26 patients who had American Association for the Surgery of Trauma grade V traumatic shattered kidneys were identified. Among them, a retrospective review was conducted of 16 patients who underwent superselective renal artery embolization for shattered kidney. The mean age was 41.2 ± 15.7 years, and the mean follow-up duration was 138.2 ± 140.1 days. Patient data including procedure details and clinical outcomes were reviewed, and the preserved volume of kidney parenchyma was calculated. RESULTS Bleeding control was achieved in 13 (81%) patients and kidney preservation was achieved in 11 (79%). There was no mortality, and the median intensive care unit stay was 1.5 days. The mean volume of remnant kidney was 122.3 ± 66.0 cm3 (70%) on the last follow-up computed tomography. The estimated glomerular filtration rate was not significantly changed after superselective renal artery embolization. CONCLUSION Superselective renal artery embolization using a microcatheter for the shattered kidney effectively controlled hemorrhage in acute stage trauma and enabled kidney preservation.

Neuroanatomical correlates of speech and singing production in chronic post-stroke aphasia.

A classical observation in neurology is that aphasic stroke patients with impairments in speech production can nonetheless sing the same utterances. This preserved ability suggests a distinctive neural architecture for singing that could contribute to speech recovery. However, to date, these structural correlates remain unknown. Here, we combined a multivariate lesion–symptom mapping and voxel-based morphometry approach to analyse the relationship between lesion patterns and grey matter volume and production rate in speech and singing tasks. Lesion patterns for spontaneous speech and cued repetition extended into frontal, temporal and parietal areas typically reported within the speech production network. Impairment in spontaneous singing was associated with damage to the left anterior–posterior superior and middle temporal gyri. Preservation of grey matter volume in the same regions where damage led to poor speech and singing production supported better performance in these tasks. When dividing the patients into fluent and dysfluent singers based on the singing performance from demographically matched controls, we found that the preservation of the left middle temporal gyrus was related to better spontaneous singing. These findings provide insights into the structural correlates of singing in chronic aphasia and may serve as biomarkers to predict treatment response in clinical trials using singing-based interventions for speech rehabilitation.

Real-time Volume Preserving Constraints for Volumetric Model on GPU

This paper presents a parallel method for simulating real-time 3D deformable objects using the volume preservation mass-spring system method on tetrahedron meshes. In general, the conventional mass-spring system is manipulated as a force-driven method because it is fast, simple to implement, and the parameters can be controlled. However, the springs in traditional mass-spring system can be excessively elongated which cause severe stability and robustness issues that lead to shape restoring, simulation blow-up, and huge volume loss of the deformable object. In addition, traditional method that uses a serial process of the central processing unit (CPU) to solve the system in every frame cannot handle the complex structure of deformable object in real-time. Therefore, the first order implicit constraint enforcement for a mass-spring model is utilized to achieve accurate visual realism of deformable objects with tough constraint error. In this paper, we applied the distance constraint and volume conservation constraints for each tetrahedron element to improve the stability of deformable object simulation using the mass-spring system and behave the same as its real-world counterparts. To reduce the computational complexity while ensuring stable simulation, we applied a method that utilizes OpenGL compute shader, a part of OpenGL Shading Language (GLSL) that executes on the graphic processing unit (GPU) to solve the numerical problems effectively. We applied the proposed methods to experimental volumetric models, and volume percentages of all objects are compared. The average volume percentages of all models during the simulation using the mass-spring system, distance constraint, and the volume constraint method were 68.21%, 89.64%, and 98.70%, respectively. The proposed approaches are successfully applied to improve the stability of mass-spring system and the performance comparison from our experimental tests also shows that the GPU-based method is faster than CPU-based implementation for all cases.

Association of Digoxin With Preserved Echocardiographic Indices in the Interstage Period: A Possible Mechanism to Explain Improved Survival?

BackgroundFor patients with hypoplastic left heart syndrome, digoxin has been associated with reduced interstage mortality after the Norwood operation, but the mechanism of this benefit remains unclear. Preservation of right ventricular (RV) echocardiographic indices has been associated with better outcomes in hypoplastic left heart syndrome. Therefore, we sought to determine whether digoxin use is associated with preservation of the RV indices in the interstage period.Methods and ResultsWe conducted a retrospective cohort study of prospectively collected data using the public use data set from the Pediatric Heart Network Single Ventricle Reconstruction trial, conducted in 15 North American centers between 2005 and 2008. We included all patients who survived the interstage period and had echocardiographic data post‐Norwood and pre‐Glenn operations. We used multivariable linear regression to compare changes in RV parameters, adjusting for relevant covariates. Of 289 patients, 94 received digoxin at discharge post‐Norwood. There were no significant differences in baseline clinical characteristics or post‐Norwood echocardiographic RV indices (RV end‐diastolic volume indexed, RV end‐systolic volume indexed, ejection fraction) in the digoxin versus no‐digoxin groups. At the end of the interstage period and after adjustment for relevant covariates, patients on digoxin had better preserved RV indices compared with those not on digoxin for the ΔRV end‐diastolic volume (11 versus 15 mL, P=0.026) and the ΔRV end‐systolic volume (6 versus 9 mL, P=0.009) with the indexed ΔRV end‐systolic volume (11 versus 20 mL/BSA1.3, P=0.034). The change in the RV ejection fraction during the interstage period between the 2 groups did not meet statistical significance (−2 versus −5, P=0.056); however, the trend continued to be favorable for the digoxin group.ConclusionsDigoxin use during the interstage period is associated with better preservation of the RV volume and tricuspid valve measurements leading to less adverse remodeling of the single ventricle. These findings suggest a possible mechanism of action explaining digoxin’s survival benefit during the interstage period.