Glutathione-depleting polymer delivering chlorin e6 for enhancing photodynamic therapy.

The therapeutic effect of photodynamic therapy (PDT) is highly dependent on the intracellular production of reactive oxygen species (ROS). However, the ROS generated by photosensitizers can be consumed by the highly concentrated glutathione (GSH) in tumor cells, severely impairing the therapeutic effect of PDT. Herein, we synthesized a GSH-scavenging copolymer to deliver photosensitizer chlorin e6 (Ce6). The pyridyl disulfide groups, which have faster reactivity with the thiol groups of GSH than other disulfide groups, were grafted onto a hydrophobic block to encapsulate the Ce6. Under NIR irradiation, the Ce6 generated ROS to kill tumor cells, and the pyridyl disulfide groups depleted the GSH to prevent ROS consumption, which synergistically enhanced the therapeutic effect of PDT. In vitro and in vivo experiments confirmed the combinatory antitumor effect of Ce6-induced ROS generation and the pyridyl disulfide group-induced GSH depletion. Therefore, the pyridyl disulfide group-grafted amphiphilic copolymer provides a more efficient strategy for enhancing PDT and has promising potential for clinical application.

Rufibacter latericius sp. nov., isolated from Baiyang Lake.

A novel Gram-stain-negative, strictly aerobic, rod-shaped, brick red-pigmented bacterium, designated R-22-1 c-1T, was isolated from water from Baiyang Lake, Hebei Province, PR China. The strain was able to grow at 20-30 °C (optimum, 30 °C) and pH 6-7 (optimum, pH 6) in Reasoner's 2A medium. 16S rRNA gene sequence and phylogenetic analyses of R-22-1 c-1T revealed closest relationships to Rufibacter immobilis MCC P1T (97.8 %), Rufibacter sediminis H-1T (97.9 %) and Rufibacter glacialis MDT1-10-3T (97.0 %), with other species of the genus Rufibacter showing less than 97.0 % sequence similarity. The predominant polar lipids were phosphatidylethanolamine, two unidentified aminophospholipids and three unidentified lipids. The major cellular fatty acids were iso-C15 : 0, C15 : 1 ω6c, C17 : 1 ω6c, anteiso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 4 (iso-C17 : 1I and/or anteiso-C17 : 1B). The respiratory quinone was MK-7. The draft genome of R-22-1 c-1T was 5.6 Mbp in size, with a G+C content of 50.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization relatedness values between strain R-22-1 c-1T and related type strains were R. immobilis MCC P1T (77.2 and 21.8 %), R. sediminis H-1T (81.6 and 21.4 %) and R. tibetensis 1351T (78.5 and 22.9 %). Based on these phylogenetic, chemotaxonomic and genotypic results, strain R-22-1 c-1T represents a novel species in the genus Rufibacter, for which the name Rufibacter latericius sp. nov. is proposed. The type strain is R-22-1 c-1T (=CGMCC 1.13570T=KCTC 62781T).

Ameliorative Effect of Curcumin-Encapsulated Hyaluronic Acid-PLA Nanoparticles on Thioacetamide-Induced Murine Hepatic Fibrosis.

In this study, we developed curcumin-encapsulated hyaluronic acid-polylactide nanoparticles (CEHPNPs) to be used for liver fibrosis amelioration. CD44, the hyaluronic acid (HA) receptor, is upregulated on the surface of cancer cells and on activated hepatic stellate cells (aHSCs) rather than normal cells. CEHPNPs could bind to CD44 and be internalized effectively through endocytosis to release curcumin, a poor water-soluble liver protective agent. Thus, CEHPNPs were potentially not only improving drug efficiency, but also targeting aHSCs. HA and polylactide (PLA) were crosslinked by adipic acid dihydrazide (ADH). The synthesis of HA-PLA was monitored by Fourier-transform infrared (FTIR) and Nuclear Magnetic Resonance (NMR). The average particle size was approximately 60-70 nm as determined by dynamic light scattering (DLS) and scanning electron microscope (SEM). Zeta potential was around -30 mV, which suggested a good stability of the particles. This drug delivery system induced significant aHSC cell death without affecting quiescent HSCs, hepatic epithelial, and parenchymal cells. This system reduced drug dosage without sacrificing therapeutic efficacy. The cytotoxicity IC50 (inhibitory concentration at 50%) value of CEHPNPs was approximately 1/30 to that of the free drug treated group in vitro. Additionally, the therapeutic effects of CEHPNPs were as effective as the group treated with the same curcumin dose intensity in vivo. CEHPNPs significantly reduced serum aspartate transaminase/alanine transaminase (ALT/AST) significantly, and attenuated tissue collagen production and cell proliferation as revealed by liver biopsy. Conclusively, the advantages of superior biosafety and satisfactory therapeutic effect mean that CEHPNPs hold great potential for treating hepatic fibrosis.

Effect of cervus and cucumis peptides on osteoblast activity and fracture healing in osteoporotic bone.

Osteoporosis is associated with delayed and/or reduced fracture healing. As cervus and cucumis are the traditional Chinese treatments for rheumatoid arthritis, we investigated the effect of supplementation of these peptides (CCP) on bone fracture healing in ovariectomized (OVX) osteoporotic rats in vitro and in vivo. CCP enhanced osteoblast proliferation and increased alkaline phosphatase activity, matrix mineralization, and expression of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 4 (BMP4), and osteopontin. In vivo, female Sprague-Dawley rats underwent ovariectomy and the right femora were fractured and fixed by intramedullary nailing 3 months later. Rats received intraperitoneal injections of either CCP (1.67 mg/kg) or physiological saline every day for 30 days. Fracture healing and callus formation were evaluated by radiography, micro-CT, biomechanical testing, and histology. At 12 weeks after fracture, calluses in CCP-treated bones showed significantly higher torsional strength and greater stiffness than control-treated bones. Bones in CCP-treated rats reunified and were thoroughly remodeled, while two saline-treated rats showed no bone union and incomplete remodeling. Taken together, these results indicate that use of CCP after fracture in osteoporotic rats accelerates mineralization and osteogenesis and improves fracture healing.

Transcatheter heart valve with variable geometric configuration: in vitro evaluation.

Clinically, the current transcatheter aortic valve (TAV) technology has shown a propensity for paravalvular leakage; studies have correlated this flaw to increased calcification at the implantation site and with nonideal geometry of the stented valve. The present study evaluated the hydrodynamics of different geometric configurations, in particular the intravalvular considerations. Three TAV devices were made to create a representative, size 26 mm TAV. Hydrodynamics were assessed using a pulse duplicator. The geometries tested were composed of the nominal, elliptical, triangular, and undersized shapes; along with half-constriction, a conformation in which only a portion of the stent was constrained. The TAVs were assessed for transvalvular pressure gradient (TVG), effective orifice area (EOA), and regurgitant fraction. The nominal-sized shape posed a larger TVG (6.2 ± 0.3 mm Hg) than other configurations (P < 0.001) except the undersized valves. EOA of the nominal sized TAV (1.7 ± 0.1 cm(2) ) was smaller than that of the triangular and half-elliptical versions (P < 0.001). The half- and full-undersized geometries had EOAs smaller than the nominal type (P < 0.001). Nominal shape had smaller regurgitation (6.7 ± 1.4%) than all configurations (P < 0.001) except for the half-undersized (4.0 ± 0.7, P < 0.001) with no statistically significant difference from the full-undersized (6.8 ± 1.3, P = 0.724). The testing of variable geometries showed significant differences from the nominal geometry with respect to TVG, EOA, and regurgitant fraction. In particular, many of these nonideal configurations demonstrated an increased intravalvular regurgitation.

[Study on differentiation of rat adipose tissue-derived stromal cells into Schwann-like cells].

OBJECTIVE: To investigate the phenotypic, molecular and biological characteristics of adipose tissue-derived stromal cells (ADSCs) differentiated alonely a Schwann cells (SCs) lineage and to provide a new cells' seed source for nerve tissue engineering or cell therapy. METHODS: Cultured ADSCs were isolated from SD rats and the undifferentiated ADSCs were confirmed by detection of MSC-specific cell-surface markers. The ADSCs were differentiated along a glial cell lineage using an established cocktail of growth factors. Following differention, we used immunofluorescene staining and RT-PCR to evaluate the characteristics of differentiated WJMSCs. RESULTS: ADSCs were successfully isolated from the rats' fat tissue. The isolated ADSCs expressed CD29, CD90 but not CD34, CD44 nor CD45. Osteogenic differentiation was detected by Alizarin red staining and adipogenic differentiation was comfirmed by Oil-red O staining. ADSCs treated with a mixture of glial growth factors adopted a spindle-like morphology similar to Schwann cells. Immunocytochemical staining and RT-PCR analysis revealed that the treated cells expressed the glial markers S100, P75 and glial fibrillary acidic protein indicative of differentiation. CONCLUSION: ADSCs can be differentiated into cells that are Schwann-like in terms of morphologic features and phenotype and could be suitable Schwann-cell substitutes for nerve repair in clinical applications.

Performance of bioprosthetic valves after glycerol dehydration, ethylene oxide sterilization, and rehydration.

OBJECTIVE: : Most commercially available bioprosthetic valves are stored in an aldehyde solution. We report a new alternative method: Self-expanding valves composed of dehydrated tissues with a high glycerin:water ratio can be collapsed into specially designed sheaths prior to sterilization for ease of delivery and storage. MATERIALS AND METHODS: : Changes in tissue dimension of five samples of bovine pericardium were evaluated from baseline after glycerol treatment, air-drying, ethylene oxide (EtO) sterilization, and rehydration with water. Three valves fabricated from glutaraldehyde cross-linked tissues, including porcine pericardial tissue, bovine pericardial tissue, and porcine aortic valve, were dehydrated through a proprietary glycerin-based process, collapsed, placed within a catheter, EtO sterilized, stored for up to 212 days, and rehydrated with water. These valves were characterized in a mock circulation by mounting them at the inlet portion of a pneumatic pump before dehydration and after rehydration to evaluate the effects of dehydration and rehydration on the valve performance. RESULTS: : Tissues treated with glycerol solution showed no significant changes in dimension from baseline after glycerol treatment, air-drying, EtO sterilization, and rehydration with water. In all the valves, pump flows reached the maximum output capacity of the pneumatic pump after rehydration without an increase in filling pressures as compared with those before dehydration. CONCLUSIONS: : This method for storing collapsible bioprosthetic valves using a proprietary glycerin-based process demonstrated excellent valve performance.

Performance of extracorporeally adjustable ventricular assist device inflow cannula.

PURPOSE: This study evaluated the feasibility and efficacy of a newly developed adjustable left ventricular assist device inflow cannula in a short-term calf model. DESCRIPTION: In this inflow cannula, the angle between the cannula body and the inflow cannula tip can be altered extracorporeally by manipulating 2 externalized cables connected to the cannula. The cannula tip is adjustable in any plane to a maximum of ±15 degrees. EVALUATION: After initial prototyping in 4 calf cadavers, a Cleveland Heart left ventricular assist device was implanted with the adjustable inflow cannula placed in the left ventricular apex and the outlet to the descending aorta. Under hypovolemic conditions, the angle of the cannula tip could be changed to induce varying degrees of ventricular suction and then eliminate it, as evidenced by recorded pump and native left ventricular flows. Epicardial echocardiography and fluoroscopy in the closed-chest condition documented extracorporeal adjustments of the inflow cannula position. CONCLUSIONS: This extracorporeally adjustable inflow cannula was effective in preventing or controlling left ventricular suction.

Mitral annular remodeling to treat functional mitral regurgitation: a pilot acute study in a canine model.

BACKGROUND: The aim of this study was to evaluate the feasibility and efficacy of the injection of a nonabsorbable substance into the base of the left ventricle (LV) to treat functional mitral regurgitation (MR). METHODS: Tyramine-based hyaluronan hydrogel was injected into the base of the LV of the beating heart in a canine model of rapid ventricular pacing-induced functional MR (n = 4). The severity of MR was evaluated by epicardial echocardiography before and after hydrogel injection. RESULTS: The injection improved MR grade from 3.4 +/- 0.8 to 1.3 +/- 0.5 (P = .006) without inducing hemodynamic instability or any evidence of myocardial ischemia. We noted significant decreases in the septal-lateral dimension at the mitral annulus (3.4 +/- 0.4 cm to 2.9 +/- 0.3 cm; P = .039) and MR volume (20.6 +/- 7.3 mm3 to 5.2 +/- 2.2 mm3; P = .044). CONCLUSIONS: A novel treatment consisting of hydrogel injection into the base of the LV between the 2 papillary muscles was found to be feasible and effective for reducing functional MR in a canine model.

In vivo biocompatibility evaluation of a new resilient, hard-carbon, thin-film coating for ventricular assist devices.

The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices.

In vivo evaluation of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14-91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.

In vivo acute performance of the Cleveland Clinic self-regulating, continuous-flow total artificial heart.

BACKGROUND: The purpose of this study was to evaluate the acute in vivo pump performance of a unique valveless, sensorless, pulsatile, continuous-flow total artificial heart (CFTAH) that passively self-balances left and right circulations without electronic intervention. METHODS: The CFTAH was implanted in two calves, with pump and hemodynamic data recorded at baseline over the full range of pump operational speeds (2,000 to 3,000 rpm) in 200-rpm increments, with pulsatility variance, and under a series of induced hemodynamic states created by varying circulating blood volume and systemic and pulmonary vascular resistance (SVR and PVR). RESULTS: Sixty of the 63 induced hemodynamic states in Case 1 and 73 of 78 states in Case 2 met our design goal of a balanced flow and maximum atrial pressure difference of 10 mm Hg. The correlation of calculated vs measured flow and SVR was high (R(2) = 0.857 and 0.832, respectively), allowing validation of an additional level of automatic active control. By varying the amplitude of sinusoidal modulation of the speed waveform, 9 mm Hg of induced pulmonary and 18 mm Hg of systemic arterial pressure pulsation were achieved. CONCLUSIONS: These results validated CFTAH self-balancing of left and right circulation, induced arterial flow and pressure pulsatility, accurate calculated flow and SVR parameters, and the performance of an automatic active control mode in an acute, in vivo setting in response to a wide range of imposed physiologic perturbations.

[Molluscicidal activity of methanol extracts of Jatropha curcas leaves against Ampullaria gigas].

OBJECTIVE: To evaluate the molluscicidal activities of methanol extract of Jatropha curcas leaves against Ampullaria gigas. METHODS: Young snails, adult snails and eggs of Ampullaria gigas were treated with the methanol extract of J. curcas leaves at different doses for different time lengths and the molluscicidal effects of the extract were evaluated. RESULTS: The methanol extract showed a significant molluscicidal effect on the young snails at a low concentration, and treatment with 75 mg/L extract for more than 3 days resulted in a 100% mortality rate of the young snails. The Jatropha leaf methanol extract also showed toxicity to adult snails and eggs. CONCLUSION: Jatropha leaves have a great potential for developing green pesticides to control Ampullaria gigas, but its biochemical mechanism needs further research.

Human clinical fitting study of the DexAide right ventricular assist device.

The DexAide right ventricular assist device (RVAD) has been developed as an implantable RVAD. The purpose of this study was to determine the final design and optimal anatomical placement of the DexAide RVAD when implanted simultaneously with either of two commercially available left ventricular assist devices (LVADs) in patients. A mock-up DexAide RVAD was used to assess configuration with each of two types of commercially available LVADs at the time of LVAD implantation in three human clinical cases. The pump body of the DexAide RVAD was placed either in the preperitoneal space or in the right thoracic cavity. The DexAide RVAD placed into the right thoracic cavity is suitable for use with the Novacor or HeartMate II LVADs. The results of this study will guide the finalization of the inflow cannula and optimal placement of the DexAide RVAD for human clinical trials.

High-sensitivity detection of fruit tree viruses using bacterial magnetic particles.

Prunus necrotic ring spot virus (PNRSV) and grapevine fanleaf virus (GFLV) were detected by fluoroimmunoassay using bacterial magnetic particles (BMPs), and a double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA). For the fluoroimmunoassay, fluorescein isothiocyanate labeled anti-PNRSV antibody or anti-GFLV antibody was conjugated onto BMPs of Magnetospirillum gryphiswaldense MSR-1. With this method, a very low minimum antigen concentration (1 x 10(6) dilution of the original sample concentration) could be detected. Using DAS-ELISA, the minimum antigen detection concentration was the original sample concentration. Thus, comparing these two methods, a BMP-based method could increase the sensitivity up to six orders of magnitude (10(6)) higher than an ELISA-based method of detection PNRSV and GFLV.

Development of DexAide right ventricular assist device: update II.

The DexAide right ventricular assist device (RVAD) is a magnetically and hydrodynamically levitated implantable centrifugal pump. Recent progress includes 1) redesign of the inflow/outflow conduits, which yielded two successful 3-month experiments, 2) development of alternative journal bearing materials, and 3) completion of an 18-month duration of in vitro endurance testing. Verification testing of the RVAD electronics has been completed, and a prototype biventricular assist device (BVAD) system has been tested. Acute DexAide/CorAide BVAD implantations via median sternotomy in two calves documented BVAD control algorithms and anatomical fit. A drug-induced chronic calf heart failure model, currently under development in our laboratory, resulted in a successful BVAD implantation in a calf with heart failure. Our future plans are to complete in vitro and in vivo validation of alternative bearing materials, perform preclinical DexAide in vivo and in vitro reliability studies, and obtain Food and Drug Administration (FDA) approval for an Investigational Device Exemption to conduct a clinical pilot study. In conclusion, two successful 3 month in vivo experiments and an 18-month in vitro endurance test were completed. After final bearing material selection, the DexAide design will be "frozen" so that preclinical systems can be manufactured. BVAD experiments using a chronic heart failure model are in progress.

Innovative, replaceable heart valve: concept, in vitro study, and acute in vivo study.

The purpose of this study was to evaluate the feasibility of our innovative, replaceable heart valves that can be easily detached from the sewing ring at the time of repeat replacement. The prototype devices consist of the base magnet ring assembly and the valve magnet ring assembly that utilize magnetic coupling force for the locking mechanism. Magnetic coupling strength was evaluated in vitro. Prototype bioprosthetic valves were implanted acutely in three sheep to confirm the feasibility of the replaceable mitral valve. The static separation force of prototype size #25 was 12.5 lb, meeting the design goal. In situ attachment and detachment of the valve magnet ring assembly from the base magnet ring assembly were very easily accomplished in all animals. The magnetic coupling did not decouple even under extremely high left ventricular pressures. We have demonstrated the feasibility of this innovative concept of a replaceable mitral valve.

Acute in vivo evaluation of an implantable continuous flow biventricular assist system.

An implantable biventricular assist device offers a considerable opportunity to save the lives of patients with combined irreversible right and left ventricular failure. The purpose of this study was to evaluate the hemodynamic and physiologic performance of the combined implantation of the CorAide left ventricular assist device (LVAD) and the DexAide right ventricular assist device (RVAD). Acute hemodynamic responses were evaluated after simulating seven different physiological conditions in two calves. Evaluation was performed by fixing the speed of one individual pump and increasing the speed of the other. Under all conditions, increased LVAD or RVAD speed resulted in increased pump flow. The predominant pathophysiologic effect of independently varying DexAide and CorAide pump speeds was that the left atrial pressure was very sensitive to increasing RVAD speed above 2,400 rpm, whereas the right atrial pressure demonstrated much less sensitivity to increasing LVAD speed. An increase in aortic pressure and RVAD flow was observed while increasing LVAD speed, especially under low contractility, ventricular fibrillation, high pulmonary artery pressure, and low circulatory blood volume conditions. In conclusion, a proper RVAD-LVAD balance should be maintained by avoiding RVAD overdrive. Additional studies will further investigate the performance of these pumps in chronic animal models.

Development of the DexAide right ventricular assist device inflow cannula.

Cannula design and cannulation site can pose major limitations to chronic pump implantations in animal studies. The aim of this study was to evaluate the biocompatibility of various inflow cannula designs for the DexAide right ventricular assist device (RVAD). The DexAide RVAD was implanted for intended durations of 14, 30, or 90 days in 19 animals (mean 20 +/- 11 days). Seven inflow cannula designs were evaluated: angled titanium conduit with caged tip (two cases); flexible polyurethane coated polyvinyl chloride (PVC) tube (one case); open ended titanium (one case); a titanium cannula with a flange (six cases); a cannula with a gelatin coated flange (five cases); a cannula with an angled flange (one case); and open ended titanium with two side holes (three cases). The open ended titanium inflow cannula with two side holes positioned through the diaphragmatic surface of the right ventricle (RV) via a right thoracotomy showed good biocompatibility for the chronic animal study. Other cannulae inserted into the infundibular portion of the RV via a left thoracotomy showed significant depositions. Gelatin coated inflow cannula had the advantage to prevent tissue growth around the inflow cannula. The DexAide RVAD pump itself showed good biocompatibility, although nonadherent depositions originating from the inflow cannulae were captured onto the primary impeller blades.

Hemodynamic and metabolic changes during exercise in calves with total artificial hearts of different sizes yet similar output.

To evaluate the effects of downsizing of the total artificial heart (TAH), we compared the anaerobic threshold (AT) values in calves with two different types of TAH (Cleveland Clinic-Nimbus TAH and the downsized MagScrew TAH). Exercise studies were performed using a treadmill in 12 calves. During the exercise, parameters to obtain the AT were measured. To evaluate the determinants of the AT, a linear regression analysis was performed between AT and potential variables. AT values from 29 studies revealed no significant differences between the two different TAHs, with no significant differences in hemodynamic or oxygen metabolic parameters. AT values correlated well with pump flow/body weight (Q) multiplied by the hemoglobin level, regardless of the TAH used. In conclusion, downsizing of the original TAH design did not reduce AT without any significant differences in hemodynamic or oxygen metabolic parameters during exercise in calves.