Self-Standing Photo-Crosslinked Hydrogel Construct: in vitro Microphysiological Vascular Model.

Modeling of the human vascular microphysiological system (MPS) has gained attention due to precise prediction of drug response and toxicity during drug screening process. Developing a physiologically equivalent vascular MPS still remains complex as it demands the recapitulation of dynamic structural and biological microenvironment similar to native vasculature. Hence, an ideal MPS would involve developing perfusable 3D in vitro models with multilayered human vascular cells encapsulated in a matrix to regulate the vascular tone resembling the native. Several attempts to model such anatomically accurate physiological and pathological blood vessels often fail to harmonize the essential vascular microenvironment. For instance, conventional microfluidic-based approaches employed for vascular MPS, though offering creation of perfusable channel, do not replicate the vascular hierarchical cellular arrangement due to planar geometry and confluent monolayered cell seeding. Also, recent advances with 3D biofabrication strategies are still limited by fabrication of small-diameter constructs and scalability besides post-processing techniques that indirectly distort the structural integrity of the hydrogel tubular constructs. These existing limitations toward fabricating a relevant vascular MPS demand a facile and mechanically stable construct. Hence, the present study is aimed toward developing a stable viable self-standing perfusable hydrogel construct by a rapid and scalable strategy toward vascular MPS application. The fabricated tubular constructs were found to be structurally stable with end-to-end perfusability exhibiting their potential as self-standing perfusable structures. Also, the construct exhibited nonhemolytic behavior with perfusion of red blood cells inside the luminal channel. The present study evidences creation of a dual-crosslinked stable, viable self-standing hydrogel construct with multilayered homogenous distribution of viable smooth muscle cells throughout the construct, thereby demonstrating its applicability as a promising 3D in vitro vascular microphysiological system.

Nanohydroxyapatite-Protein Interface in Composite Sintered Scaffold Influences Bone Regeneration in Rabbit Ulnar Segmental Defect.

The healing physiology of bone repair and remodeling that occurs after normal fracture is well orchestrated. However, it fails in complex clinical conditions and hence requires augmentation by grafts. In this study, composite nanohydroxyapatite (nHA), poly(hydroxybutyrate) (PHB) and poly(ɛ-caprolactone) (PCL) constituted microspheres sintered three-dimensional scaffold were evaluated in rabbit ulnar segmental defect. A composite scaffold using PHB-PCL-nHA microspheres was developed with protein interface by solvent/non-solvent sintering to provide multiple cues such as biocomposition, cancellous bone equivalent meso-micro multi-scale porosity, and compressive strength. In vitro DNA quantification and alkaline phosphatase (ALP) assays revealed that the protein interfaced composite scaffolds supported osteoblast proliferation and mineralization significantly higher than scaffolds without protein and TCPS (p < 0.05). Scanning electron micrographs of osteoblasts cultured scaffolds demonstrated cell-matrix interaction, cell spreading, colonization and filopodial extension across the porous voids. Cylindrical scaffolds (5 × 10 mm) were implanted following segmental defect (10 mm) in rabbit ulnar bone and compared with untreated control. Radiography (4, 8 and 12 weeks) and µ-computed tomography (12 weeks) analysis showed directional bone tissue formation by bridging defective site in both scaffolds with and without protein interface. Whereas, undesired sclerotic-like tissue formation was observed in control groups from 8 weeks. Histology by hot Stevenel's blue and van Gieson's picrofuchsin staining has confirmed enhanced bone maturation in scaffold groups while presence of osteoids was observed in control after 12 weeks. Thus, the developed composite matrices exhibits osteoinductive, osteoconductive properties and demonstrates its bone regenerative potential owing to its compositional, micro & macro structural and mechanical properties. Graphical abstract.

Perceived social support, depression and their impact on quality of life of people living with HIV in India.

Universal access to Antiretroviral Treatment (ART) has transformed HIV/AIDS into a chronic disease and issues like social support and Quality of life (QOL) have emerged as important components of care. Perceived social support influences QOL in People Living with HIV (PLHIV), though this has not been studied well in India. PLHIV were assessed for Social Support using the Multidimensional Scale of Perceived Social Support (MSPSS) and QOL was assessed with the Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire. The factors impacting social support and its effect of on QOL were analysed. Amongst the 109 study subjects, 62 (56.9%) were men, 47 (43.1%) were women, mean age was 35 ± 7.5 years, 85.3% had WHO stage 1 disease and 80 (73.4%) were receiving ART. Only 43.1% subjects perceived high overall social support. Social support (from family/friends/others) was associated positively with physical functioning (p = 0.001), social and cognitive functioning (p = 0.000) and significantly inversely associated with depression (p = 0.002). Higher perceived social support was seen to correlate with higher CD4 count (Peak, Nadir and Current; p < 0.05) and better adherence (p = 0.003). It is concluded that social support, including support from beyond family, have a significant impact on clinical endpoints and QOL in PLHIV.

Continuous low-intensity ultrasound attenuates IL-6 and TNFα-induced catabolic effects and repairs chondral fissures in bovine osteochondral explants.

BACKGROUND: Cartilage repair outcomes are compromised in a pro-inflammatory environment; therefore, the mitigation of pro-inflammatory responses is beneficial. Treatment with continuous low-intensity ultrasound (cLIUS) at the resonant frequency of 5 MHz is proposed for the repair of chondral fissures under pro-inflammatory conditions. METHODS: Bovine osteochondral explants, concentrically incised to create chondral fissures, were maintained under cLIUS (14 kPa (5 MHz, 2.5 Vpp), 20 min, 4 times/day) for a period of 28 days in the presence or absence of cytokines, interleukin-6 (IL-6) or tumor necrosis factor (TNF)α. Outcome assessments included histological and immunohistochemical staining of the explants; and the expression of catabolic and anabolic genes by qRT-PCR in bovine chondrocytes. Cell migration was assessed by scratch assays, and by visualizing migrating cells into the hydrogel core of cartilage-hydrogel constructs. RESULTS: Both in the presence and absence of cytokines, higher percent apposition along with closure of fissures were noted in cLIUS-stimulated explants as compared to non-cLIUS-stimulated explants on day 14. On day 28, the percent apposition was not significantly different between unstimulated and cLIUS-stimulated explants exposed to cytokines. As compared to non-cLIUS-stimulated controls, on day 28, cLIUS preserved the distribution of proteoglycans and collagen II in explants despite exposure to cytokines. cLIUS enhanced the cell migration irrespective of cytokine treatment. IL-6 or TNFα-induced increases in MMP13 and ADAMTS4 gene expression was rescued by cLIUS stimulation in chondrocytes. Under cLIUS, TNFα-induced increase in NF-κB expression was suppressed, and the expression of collagen II and TIMP1 genes were upregulated. CONCLUSION: cLIUS repaired chondral fissures, and elicited pro-anabolic and anti-catabolic effects, thus demonstrating the potential of cLIUS in improving cartilage repair outcomes.

Correction to: Axially aligned electrically conducting biodegradable nanofibers for neural regeneration.

The original version of this article unfortunately contained a mistake. The presentation of Fig. 2e was incorrect. The corrected version of Fig. 2E1 is given below.

Responsive Nanomicellar Theranostic Cages for Metastatic Breast Cancer.

Precluding the progression of metastasis with early diagnosis of triple-negative breast cancer remains challenging due to lack of targeting specificity with poor diagnostic potential. Herein, an amphipathic chitosan-based targeted nanomicellar theranostics (30-45 nm) comprising doxorubicin-superparamagnetic iron oxide nanoparticles complexes (89.23%) with lower critical micelle concentration (0.1 µg/mL) were developed. Micelles exhibit concentration-based contrast enhancement in MRI (r2 6.27 mM-1 s-1) and hyperthermia rather than thermal-ablation. This theranostics delivers doxorubicin under alternating magnetic field (480 kHz) and at endosomal pH (pH 5.2) while showing stability at pH 7.4. Anti-αvß3 integrin antibody conjugation onto PEGylated micelles (62.3%) enhances micellar internalization into drug-resistant MDA-MB-231 after 1 h and magnetizes the cells after 6 h over that with nonconjugated micelles. Immigration of MDA-MB-231 and 4T1 cells retards after 24 h, while significant reduction of mitochondrial membrane potential is observed under hyperthermia. Intratumoral administration of nanomicelles in 4T1 orthotopic spontaneous metastasis model demonstrated antitumor and fibrosis mediated caging effect with simultaneous enhancement of MRI-T2 contrast.

Surface topography of polylactic acid nanofibrous mats: influence on blood compatibility.

Fabricating nanofibrous scaffolds with robust blood compatibility remains an unmet challenge for cardiovascular applications since anti-thrombogenic surface coatings did not withstand physiological shear force. Hence, the present study envisages the influence of smooth and porous topographies of poly(lactic acid) (PLA) nanofibers on hemocompatibility as it could offer time-independent blood compatibility. Further, recent studies have evolved to integrate various contrasting agents for augmenting the prognostic properties of tissue engineered scaffolds; an attempt was also made to synthesize Curcumin-superparamagnetic iron oxide nanoparticle complex (Cur-SPION) as a contrasting agent and impregnated into PLA nanofibers for evaluating the blood compatibility. Herein, electrospun nanofibers of PLA with different topographies (smooth and porous) were fabricated and characterized for surface morphology, zeta potential, fluorescence, and crystallinity. The scaffolds with smooth, porous and rough surface topographies were thoroughly investigated for its hemocompatibility by evaluating hemolysis percentage, platelet adhesion, in vitro kinetic clotting time, serum protein adsorption, plasma recalcification time (PRT), capture and release of erythrocytes. Although the nanofibers of all three groups showed acceptable hemolytic percentage (HP < 5%), the adhered RBCs on Cur-SPION based fibers undergo morphological transformation from biconcave discocytes to echinocytes with cube-like protrusions. On the contrary, no morphological changes were observed in RBCs cultured on smooth and porous nanofibers. Porous fibers exhibited excellent anti-thrombogenic property and adhered lesser platelets and maintained the discoidal morphology of native platelets. Cur-SPION integrated PLA nanofibers showed inactivated platelets with anti-thrombogenic activity compared to smooth nanofibers. In conclusion, PLA nanofibers porous topography did not affect the RBC membrane integrity and maintained discoidal morphology of platelets with superior anti-thrombogenic activity. However, smooth and Cur-SPION integrated PLA nanofibers were found to activate the platelets and deform the RBC membrane integrity, respectively. Hence, the nanofibers with porous structures provide an ideal topography for time-independent hemocompatibility.

Injectable and 3D Bioprinted Polysaccharide Hydrogels: From Cartilage to Osteochondral Tissue Engineering.

Biomechanical performance of functional cartilage is executed by the exclusive anisotropic composition and spatially varying intricate architecture in articulating ends of diarthrodial joint. Osteochondral tissue constituting the articulating ends comprise superfical soft cartilage over hard subchondral bone sandwiching interfacial soft-hard tissue. The shock-absorbent, lubricating property of cartilage and mechanical stability of subchondral bone regions are rendered by extended chemical structure of glycosaminoglycans and mineral deposition, respectively. Extracellular matrix glycosaminoglycans analogous polysaccharides are major class of hydrogels investigated for restoration of functional cartilage. Recently, injectable hydrogels have gained momentum as it offers patient compliance, tunable mechanical properties, cell deliverability, and facile administration at physiological condition with long-term functionality and hyaline cartilage construction. Interestingly, facile modifiable functional groups in carbohydrate polymers impart tailorability of desired physicochemical properties and versatile injectable chemistry for the development of highly potent biomimetic in situ forming scaffold. The scaffold design strategies have also evolved from single component to bi- or multilayered and graded constructs with osteogenic properties for deep subchondral regeneration. This review highlights the significance of polysaccharide structure-based functions in engineering cartilage tissue, injectable chemistries, strategies for combining analogous matrices with cells/stem cells and biomolecules and multicomponent approaches for osteochondral mimetic constructs. Further, the rheology and precise spatiotemporal positioning of cells in hydrogel bioink for rapid prototyping of complex three-dimensional anisotropic cartilage have also been discussed.

Theoretically proposed optimal frequency for ultrasound induced cartilage restoration.

BACKGROUND: Matching the frequency of the driving force to that of the system's natural frequency of vibration results in greater amplitude response. Thus we hypothesize that applying ultrasound at the chondrocyte's resonant frequency will result in greater deformation than applying similar ultrasound power at a frequency outside of the resonant bandwidth. Based on this resonant hypothesis, our group previously confirmed theoretically and experimentally that ultrasound stimulation of suspended chondrocytes at resonance (5 MHz) maximized gene expression of load inducible genes. However, this study was based on suspended chondrocytes. The resonant frequency of a chondrocyte does not only depend on the cell mass and intracellular stiffness, but also on the mechanical properties of the surrounding medium. An in vivo chondrocyte's environment differs whether it be a blood clot (following microfracture), a hydrogel or the pericellular and extracellular matrices of the natural cartilage. All have distinct structures and compositions leading to different resonant frequencies. In this study, we present two theoretical models, the first model to understand the effects of the resonant frequency on the cellular deformation and the second to identify the optimal frequency range for clinical applications of ultrasound to enhance cartilage restoration. RESULTS: We showed that applying low-intensity ultrasound at the resonant frequency induced deformation equivalent to that experimentally calculated in previous studies at higher intensities and a 1 MHz frequency. Additionally, the resonant frequency of an in vivo chondrocyte in healthy conditions, osteoarthritic conditions, embedded in a blood clot and embedded in fibrin ranges from 3.5 - 4.8 MHz. CONCLUSION: The main finding of this study is the theoretically proposed optimal frequency for clinical applications of therapeutic ultrasound induced cartilage restoration is 3.5 - 4.8 MHz (the resonant frequencies of in vivo chondrocytes). Application of ultrasound in this frequency range will maximize desired bioeffects.

Multichannel Conduits with Fascicular Complementation: Significance in Long Segmental Peripheral Nerve Injury.

Despite the advances in tissue engineering approaches, reconstruction of long segmental peripheral nerve defects remains unsatisfactory. Although autologous grafts with proper fascicular complementation have shown meaningful functional recovery according to the Medical Research Council Classification (MRCC), the lack of donor nerve for such larger defect sizes (>30 mm) has been a serious clinical issue. Further clinical use of hollow nerve conduits is limited to bridging smaller segmental defects of denuded nerve ends (<30 mm). Recently, bioinspired multichannel nerve guidance conduits (NGCs) gained attention as autograft substitutes as they mimic the fascicular connective tissue microarchitecture in promoting aligned axonal outgrowth with desirable innervation for complete sensory and motor function restoration. This review outlines the hierarchical organization of nerve bundles and their significance in the sensory and motor functions of peripheral nerves. This review also emphasizes the major challenges in addressing the longer nerve defects with the role of fascicular arrangement in the multichannel nerve guidance conduits and the need for fascicular matching to accomplish complete functional restoration, especially in treating long segmental nerve defects. Further, currently available fabrication strategies in developing multichannel nerve conduits and their inconsistency in existing preclinical outcomes captured in this review would seed a new process in designing an ideal larger nerve conduit for peripheral nerve repair.

Continuous Low-Intensity Ultrasound Improves Cartilage Repair in Rabbit Model of Subchondral Injury.

Subchondral drilling (SD), a bone marrow stimulation technique, is used to repair cartilage lesions that lack regenerative potential. Cartilage repair outcomes upon SD are typically fibrocartilaginous in nature with inferior functionality. The lack of cues to foster the chondrogenic differentiation of egressed mesenchymal stromal cells upon SD can be attributed for the poor outcomes. Continuous low-intensity ultrasound (cLIUS) at 3.8 MHz is proposed as a treatment modality for improving cartilage repair outcomes upon marrow stimulation. Bilateral defects were created by SD on the femoral medial condyle of female New Zealand white rabbits (n = 12), and the left joint received cLIUS treatment (3.8 MHz, 3.5 Vpp, 8 min/application/day) and the contralateral right joint served as the control. On day 7 postsurgery, synovial fluid was aspirated, and the cytokine levels were assessed by Quantibody™ assay. Rabbits were euthanized at 8 weeks and outcomes were assessed macroscopically and histologically. Defect areas in the right joints exhibited boundaries, incomplete fill, irregular cartilage surfaces, loss of glycosaminoglycan (GAG), and absence of chondrocytes. In contrast, the repaired defect area in the joints that received cLIUS showed complete fill, positive staining for GAG with rounded chondrocyte morphology, COL2A1 staining, and columnar organization. Synovial fluid collected from cLIUS-treated left knee joints had lower levels of IL1, TNFα, and IFNγ when compared to untreated right knee joints, alluding to the potential of cLIUS to mitigate early inflammation. Further at 8 weeks, left knee joints (n = 12) consistently scored higher on the O'Driscoll scale, with a higher percent hyaline cartilage score. No adverse impact on bone or change in the joint space was noted. Upon a single exposure of cLIUS to TNFα-treated cells, nuclear localization of pNFκB and SOX9 was visualized by double immunofluorescence and the expression of markers associated with the NFκB pathway was assayed by quantitative real-time polymerase chain reaction. cLIUS extends its chondroprotective effects by titrating pNFκB levels, preventing its nuclear translocation, while maintaining the expression of SOX9, the collagen II transcription factor. Our combined results demonstrate that healing of chondral defects treated with marrow stimulation by SD can be accelerated by employing cLIUS regimen that possesses chondroinductive and chondroprotective properties. Impact statement Repair of cartilage represents an unsolved biomedical burden. In vitro, continuous low-intensity ultrasound (cLIUS) has been demonstrated to possess chondroinductive and chondroprotective potential. To our best knowledge, the use of cLIUS to improve cartilage repair outcomes upon marrow stimulation, in vivo, has not been reported and our work reported here fills that gap. Our results demonstrated enhanced cartilage repair outcomes under cLIUS (3.8 MHz) in a rabbit model of subchondral injury by subchondral drilling. Enhanced repair stemmed from mesenchymal stem cell differentiation in vivo and the subsequent synthesis of articular cartilage-specific matrix.

Environmental risk factors for Pneumocystis pneumonia hospitalizations in HIV patients.

BACKGROUND: Pneumocystis pneumonia (PcP) is the second leading cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients in the United States. Although the host risk factors for the development of PcP are well established, the environmental (climatological, air pollution) risk factors are poorly understood. The major goal of this study was to determine the environmental risk factors for admissions of HIV-positive patients with PcP to a single medical center. METHODS: Between 1997 and 2008, 457 HIV-positive patients with microscopically confirmed PcP were admitted to the San Francisco General Hospital. A case-crossover design was applied to identify environmental risk factors for PcP hospitalizations. Climatological and air pollution data were collected from the Environmental Protection Agency and Weather Warehouse databases. Conditional logistic regression was used to evaluate the association of each environmental factor and PcP hospital admission. RESULTS: Hospital admissions were significantly more common in the summer than in the other seasons. Increases in temperature and sulfur dioxide levels were independently associated with hospital admissions for PcP, but the effects of sulfur dioxide were modified by increasing carbon monoxide levels. CONCLUSIONS: This study identifies both climatological and air pollution constituents as independent risk factors for hospitalization of HIV-positive patients with PcP in San Francisco. Thus, the environmental effects on PcP are more likely complex than previously thought. Further studies are needed to understand how these factors exert their effects and to determine if these factors are associated with PcP in other geographic locations.

The effect of ultrasound stimulation on the cytoskeletal organization of chondrocytes seeded in three-dimensional matrices.

The impact of low-intensity diffuse ultrasound (LIDUS) stimulation on the cytoskeletal organization of chondrocytes seeded in three-dimensional (3D) scaffolds was evaluated. Chondrocytes seeded on 3D chitosan matrices were exposed to LIDUS at 5.0 MHz (approx. 15 kPa, 51 s, 4 applications/day) in order to study the organization of actin, tubulin and vimentin. The results showed that actin presented a punctate cytosolic distribution and tubulin presented a quasiparallel organization of microtubules, whereas vimentin distribution was unaffected. Chondrocytes seeded on 3D scaffolds responded to US stimulation by the disruption of actin stress fibers and were sensitive to the presence of Rho-activated kinase (ROCK) inhibitor (Y27632). The gene expression of ROCK-I, a key element in the formation of stress fibers and mDia1, was significantly upregulated under the application of US. We conclude that the results of both the cytoskeletal analyses and gene expression support the argument that the presence of punctate actin upon US stimulation was accompanied by the upregulation of the RhoA/ROCK pathway.

Laparoscopic ventral hernia repair: primary versus secondary hernias.

BACKGROUND: Most studies regarding laparoscopic ventral hernia repair (LVHR) have merged primary hernias (PHs) and secondary (incisional) hernias (SHs) into one group of ventral hernias. This grouping could produce falsely favorable results for LVHR. Our objective was to review and compare the outcomes of laparoscopic repair of PHs and SHs. METHODS: A retrospective chart review of patients from 2000 to 2010 identified the cases of LVHR at two affiliated institutions. The demographics, comorbidities, type of hernia (PH versus SH), and short- and long-term complications were analyzed. The postoperative pain, cosmetic satisfaction, and Activities Assessment Scale scores were assessed by telephone survey. RESULTS: A total of 201 cases of LVHR were identified: 73 PHs (36%) and 128 SHs (64%). No difference was found in the mean age between the two groups. The PH group had a greater percentage of black patients (34% versus 14%; P < 0.05), and the SH group had a greater percentage of white patients (85% versus 65%; P < 0.05). More female patients had SHs (34% versus 14%; P < 0.05), and more male patients had PHs (86% versus 66%; P < 0.05). More patients in the SH group had chronic obstructive pulmonary disease (19% versus 7%; P < 0.05) and prostate disease (32% versus 9%; P < 0.05). Overall, the SHs were larger (37.9 ± 4.9 cm(2)versus 11.5 ± 1.9 cm(2); P < 0.01). No differences were found in early postoperative complications, including pneumonia, urinary tract infection, surgical site infection, and seromas between the two groups. However, those with SHs had a greater incidence of recurrence (16% versus 5%; P < 0.05) and mesh explantation (7% versus 0%; P < 0.05). The patients who also underwent SH repairs had greater postoperative pain scores when followed up for a median of 25 mo than those who underwent PH repairs when followed up for a median of 24 mo (3.5 ± 0.4 versus 1.8 ± 0.4; P < 0.05). More patients in the SH group had chronic pain issues (26% versus 5%; P = 0.0003) and had lower satisfaction scores (7.5 ± 0.3 versus 8.6 ± 0.3; P < 0.05). Overall, the Activities Assessment Scale scores were not significantly different. CONCLUSIONS: Our data have demonstrated that PHs and SHs are different. LVHR of SHs is associated with increased recurrence, greater postoperative pain scores, chronic pain issues, and lower patient satisfaction scores. We recommend that future studies evaluate LVHR for PHs separate from those for SHs.

Dihydropteroate synthase mutations in Pneumocystis pneumonia: impact of applying different definitions of prophylaxis, mortality endpoints and mutant in a single cohort.

Pneumocystis jirovecii dihydropteroate synthase (DHPS) gene mutations are well-reported. Although sulfa prophylaxis generally is associated with DHPS mutant infection, whether mutant infection is associated with poorer clinical outcomes is less clear. The differing definitions of sulfa prophylaxis and the different mortality endpoints used in these studies may be one explanation for the conflicting study results. Applying different definitions of prophylaxis, mortality endpoints and DHPS mutant to 301 HIV-infected patients with Pneumocystis pneumonia, we demonstrate that prophylaxis, irrespective of definition, increased the risk of infection with pure mutant (any prophylaxis: AOR 4.00, 95% CI: 1.83-8.76, P < 0.001) but not mixed genotypes (any prophylaxis: AOR 0.78, 95% CI: 0.26-2.36, P = 0.65). However, infection with mutant DHPS, irrespective of definition, was not associated with increased mortality (all-cause or PCP death) at the three time-intervals examined (all P > 0.05). Future studies should standardize key variables associated with DHPS mutant infection as well as examine DHPS mutant subtypes (pure mutant vs. mixed infections) - perhaps even individual DHPS mutant genotypes - so that data can be pooled to better address this issue.

Self-assembled multifunctional nanotheranostics against circulating tumor clusters in metastatic breast cancer.

Circulating tumor clusters (CTC) disseminating from the primary tumor are responsible for secondary tumor formation where the conventional treatments such as chemotherapy and radiotherapy does not prevent the metastasis at locally advanced stage of breast cancer. In this study, a smart nanotheranostic system has been developed to track and eliminate the CTCs before it can colonize at a new site, which would reduce metastatic progression and increase the five-year survival rate of the breast cancer patients. Targeted multiresponsive (magnetic hyperthermia and pH) nanomicelles incorporated with NIR fluorescent superparamagnetic iron oxide nanoparticles were developed based on self-assembly for dual modal imaging and dual toxicity for spontaneous killing of CTCs in blood stream. A heterogenous tumor clusters model was developed to mimic the CTCs isolated from breast cancer patients. The nanotheranostic system was further evaluated for the targeting property, drug release kinetics, hyperthermia and cytotoxicity against developed CTC model in vitro. In vivo model in BALB/c mice equivalent to stage III and IV human metastatic breast cancer was developed to evaluate the biodistribution and therapeutic efficacy of micellar nanotheranostic system. Reduced CTCs in blood stream and low distant organ metastasis after treatment with the nanotheranostic system demonstrates its potential to capture and kill the CTCs that minimize the secondary tumor formation at distant sites.

Oral and airway microbiota in HIV-infected pneumonia patients.

Despite the increased frequency of recurrent pneumonia in HIV-infected patients and recent studies linking the airway bacterial community (microbiota) to acute and chronic respiratory infection, little is known of the oral and airway microbiota that exist in these individuals and their propensity to harbor pathogens despite antimicrobial treatment for acute pneumonia. This pilot study compared paired samples of the oral and airway microbiota from 15 hospitalized HIV-infected patients receiving antimicrobial treatment for acute pneumonia. Total DNA was extracted, bacterial burden was assessed by quantitative PCR, and amplified 16S rRNA was profiled for microbiome composition using a phylogenetic microarray (16S rRNA PhyloChip). Though the bacterial burden of the airway was significantly lower than that of the oral cavity, microbiota in both niches were comparably diverse. However, oral and airway microbiota exhibited niche specificity. Oral microbiota were characterized by significantly increased relative abundance of multiple species associated with the mouth, including members of the Bacteroides, Firmicutes, and TM7 phyla, while airway microbiota were primarily characterized by a relative expansion of the Proteobacteria. Twenty-two taxa were detected in both niches, including Streptococcus bovis and Chryseobacterium species, pathogens associated with HIV-infected populations. In addition, we compared the airway microbiota of five of these patients to those of five non-HIV-infected pneumonia patients from a previous study. Compared to the control population, HIV-infected patients exhibited relative increased abundance of a large number of phylogenetically distinct taxa, which included several known or suspected pathogenic organisms, suggesting that recurrent pneumonia in HIV-infected populations may be related to the presence of these species.

Effect of fiber diameter on the spreading, proliferation and differentiation of chondrocytes on electrospun chitosan matrices.

Tissue-engineered neocartilage with appropriate biomechanical properties holds promise not only for graft applications but also as a model system for controlled studies of chondrogenesis. Our objective in the present research study is to better understand the impact of fiber diameter on the cellular activity of chondrocytes cultured on nanofibrous matrices. By using the electrospinning process, fibrous scaffolds with fiber diameters ranging from 300 nm to 1 µm were prepared and the physicomechanical properties of the scaffolds were characterized. Bovine articular chondrocytes were then seeded and maintained on the scaffolds for 7 and 14 days in culture. An upregulation in the gene expression of collagen II was noted with decreasing fiber diameters. For cells that were cultured on scaffolds with a mean fiber diameter of 300 nm, a 2-fold higher ratio of collagen II/collagen I was noted when compared to cells cultured on sponge-like scaffolds prepared by freeze drying and lyophilization. Integrin (α(5), αv, ß(1)) gene expression was also observed to be influenced by matrix morphology. Our combined results suggest that matrix geometry can regulate and promote the retention of the chondrocyte genotype.

Mesh shift following laparoscopic ventral hernia repair.

INTRODUCTION: Traditionally, laparoscopic ventral hernia repair (LVHR) is performed by placing the trocars on one side of the abdomen. Tacking the mesh on the operative side can be challenging. We hypothesized that mesh shift may occur as a result of this approach. We define mesh shift as any mesh off-center, where the center is the hernia defect. Our objectives were to evaluate whether mesh shift occurs after LVHR, and to develop a grading system to describe this phenomenon. METHODS: We conducted a retrospective review of patients who underwent LVHR from 2000 to 2010. We examined patient demographics, comorbidities, radiographic data, surgical data, and outcomes. Using analysis of variance, we analyzed continuous data; we used Chi squared to analyze categorical data. Of the 201 patients, we reviewed 78 postoperative computed tomography (CT) scans. Two surgeons measured mesh overlap of the fascia bilaterally at the level of the hernia defect. We compared a ratio of the two sides of overlap (least overlap/greatest overlap) and classified patients into four grades: grade I, no mesh shift (ratio of 0.5-1.00); grade II, mild mesh shift (ratio of 0.20-0.49); grade III, moderate mesh shift (>0-0.19); and grade IV, major mesh shift with recurrence (<0). Any recurrence was classified as a grade IV shift. RESULTS: A total of 48% of patients had mesh shift (grade II = 23%; grade III = 10%; and grade IV = 17%). In 92% of the patients with mesh shift, the mesh migrated away from the port placement site, resulting in decreased mesh/fascial overlap. Patients in the four groups had similar demographics, comorbid conditions, hernia characteristics, operative technique, and outcomes (excluding recurrences, which were all grade IV by definition). Whereas differences in time to follow-up CT scan in the different grades were not statistically significant, there was a trend toward increasing shift with time (mean: grade I, 20 mo; grade II, 38 mo; grade III, 50 mo; and grade IV, 26 mo; P = 0.07). A total of 26 patients (33%) had multiple postoperative CT scans. With time, it appears that mesh tended to shift with time (grade I, 68%-46%; grade II, 12%-19%; grade III, 12%-8%, and grade 4, 8%-23%). CONCLUSIONS: Mesh can shift from the ideal central placement after LVHR. Mesh tends to shift away from the operative side and recurrences tend to occur on the operative side. Mesh shift may be a precursor to hernia recurrence. Recurrence may be a two-step process, beginning first with intra-operative mesh shift followed by additional factors (such mesh contraction) that may accentuate the shift and lead to recurrence. Potential solutions include increasing mesh overlap (≥ 6 cm), performing transcutaneous closure of central defect, securing trans-fascial sutures before tacking, placing operative side tacks first, and consider placing contralateral ports to secure the mesh.

Axially aligned electrically conducting biodegradable nanofibers for neural regeneration.

In this study, electrically conducting axially aligned nanofibers have developed to provide both electrical and structural cues. Poly(lactide-co-glycolide) (PLGA) with poly(3-hexylthiophene) (PHT) was electrospun into 2D random (196 ± 98 nm) and 3D axially aligned nanofibers (200 ± 80 nm). Electrospun random and aligned PLGA-PHT fibers were characterized for surface morphology, mechanical property, porosity, degradability, and electrical conductivity. The pore size of random PLGA-PHT nanofibers (6.0 ± 3.3 µm) were significantly higher than the aligned (1.9 ± 0.4 µm) (P < 0.05) and the Young's modulus of aligned scaffold was significantly lower than the random. Aligned nanofibers showed significantly lesser degradation rate and higher electrical conductivity (0.1 × 10(-5) S/cm) than random nanofibers (P < 0.05). Results of in vitro cell studies indicate that aligned PLGA-PHT nanofibers have a significant influence on the adhesion and proliferation of Schwann cells and could be potentially used as scaffold for neural regeneration.