Differential cytotoxicity of copper ferrite nanoparticles in different human cells

Copper ferrite nanoparticles (NPs) have the potential to be applied in biomedical fields such as cell labeling and hyperthermia. However, there is a lack of information concerning the toxicity of copper ferrite NPs. We explored the cytotoxic potential of copper ferrite NPs in human lung (A549) and liver (HepG2) cells. Copper ferrite NPs were crystalline and almost spherically shaped with an average diameter of 35 nm. Copper ferrite NPs induced dose‐dependent cytotoxicity in both types of cells, evident by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazoliumbromide and neutral red uptake assays. However, we observed a quite different susceptibility in the two kinds of cells regarding toxicity of copper ferrite NPs. Particularly, A549 cells showed higher susceptibility against copper ferrite NP exposure than those of HepG2 cells. Loss of mitochondrial membrane potential due to copper ferrite NP exposure was observed. The mRNA level as well as activity of caspase‐3 enzyme was higher in cells exposed to copper ferrite NPs. Cellular redox status was disturbed as indicated by induction of reactive oxygen species (oxidant) generation and depletion of the glutathione (antioxidant) level. Moreover, cytotoxicity induced by copper ferrite NPs was efficiently prevented by N‐acetylcysteine treatment, which suggests that reactive oxygen species generation might be one of the possible mechanisms of cytotoxicity caused by copper ferrite NPs. To the best of our knowledge, this is the first report showing the cytotoxic potential of copper ferrite NPs in human cells. This study warrants further investigation to explore the mechanisms of differential toxicity of copper ferrite NPs in different types of cells. Copyright © 2016 John Wiley & Sons, Ltd.     

Integration of genotypic and phenotypic screening reveals molecular mediators of melanoma-stromal interaction

Tumor-endothelium interactions are critical for tumor survival and metastasis. Melanomas can rapidly metastasize early in tumor progression, but the dependence of this aggressive behavior on tumor-stromal interaction is poorly understood. To probe the mechanisms involved, we developed a heterotypic coculture methodology, allowing simultaneous tracking of genomic and phenotypic changes in interacting tumor and endothelial cells in vitro. We found a dramatic rearrangement of endothelial cell networks into patterns reminiscent of vascular beds, even on plastic and glass. Multiple genes were upregulated in the process, many coding for cell surface and secreted proteins, including Neuropilin-2 (NRP2). A critical role of NRP2 in coordinated cell patterning and growth was confirmed using the coculture system. We conclude that NRP2 represents an important mediator of melanoma-endothelial interactions. Furthermore, the described methodology represents a powerful yet simple system to elucidate heterotypic intercellular interactions mediating diverse physiological and pathological processes.     

Paradoxical signaling pathways in developing thymocytes

Thymocytes are subjected to processes of selection during their life in the thymus; negative selection for autoreactive thymocytes and positive selection for self-MHC restricted self-tolerant cells. Interestingly, signals for positive or negative selection originate from the same receptor. More importantly, evidence showed that both death and survival signals are mediated by the MAPK pathway. The degree and order of ERK activation, but not other MAPK proteins, has been found to be different in either cases of cell fate. Therefore, it is suspected that the kinetics of ERK after activation may dictate cell death or survival. There are two important GEF proteins that are involved in Ras/ERK activation, RasGRP and SOS. It is thought that the level, order and kinetics of ERK are influenced upstream by the type of GEF. This review discusses the role of both GEF proteins in positive and negative selection and how this reflects on ERK activation.     

Co-delivery of cancer-associated antigen and Toll-like receptor 4 ligand in PLGA nanoparticles induces potent CD8+ T cell-mediated anti-tumor immunity

The purpose of this study was to evaluate the efficacy of poly(lactic-co-glycolic acid) (PLGA)-based vaccines in breaking immunotolerance to cancer-associated self-antigens. Vaccination of mice bearing melanoma B16 tumors with PLGA nanoparticles (NP) co-encapsulating the poorly immunogenic melanoma antigen, tyrosinase-related protein 2 (TRP2), along with Toll-like receptor (TLR) ligand (7-acyl lipid A) was examined. Remarkably, this vaccine was able to induce therapeutic anti-tumor effect. Activated TRP2-specific CD8 T cells were capable of interferon (IFN)-gamma secretion at lymph nodes and spleens of the vaccinated mice. More importantly, TRP2/7-acyl lipid A-NP treated group has shown immunostimulatory mileu at the tumor microenvironment, as evidenced by increased level of pro-inflammatory cytokines compared to control group. These results support the potential use of PLGA nanoparticles as competent carriers for future cancer vaccine formulations.     

Real-time-guided bone regeneration around standardized critical size calvarial defects using bone marrow-derived mesenchymal stem cells and collagen membrane with and without using tricalcium phosphate:an in vivo micro-computed tomographic and histologic experiment in rats

The aimof the present real time in vivo micro-computed tomography (mCT) and histologic experiment was to assess the efficacy of guided bone regeneration (GBR) around standardized calvarial critical size defects (CSD) using bone marrow-derived mesenchymal stem cells (BMSCs), and collagen membrane (CM) with and without tricalcium phosphate (TCP) graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD (diameter 4.6 mm) were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone (NFB) and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo mCT. At the 10th week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness ofNFBwas similar to that of the native bone in groups 1 and 2 as compared to theNFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical “lock” between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adjunct BMSC therapy.     

The directions of static skin tensions in the face: their roles in facial incisions.

The circular excisions of facial skin lesions were performed in 202 sites on 126 patients. The shapes of the resultant defects were observed to identify the directions of skin tensions in a static state. The round shapes remained in the forehead, temple, and nose. In the other areas of the face, the wounds were stretched in certain directions and became elliptical. The orientations of the facial static tensions were identical to the wrinkle lines in many facial areas. It is suggested that the wrinkle lines show the optimal directions of selective incisions in most facial areas except for the medial canthus and upper and lower lips.     

Role of oxygen-derived free radicals in mechanism of acute and chronic duodenal ulceration in the rat

This study employed the oxygen-derived free radical removing agents DL-cysteine, methyl-methionine sulfonium bromide (MMSB), dimethyl sulfoxide (DMSO), and allopurinol to examine the role of oxyradicals in the mechanism of acute and chronic duodenal ulceration in the rat. These agents were administered by gavage under light ether anesthesia. All rats infused subcutaneously for 24 hr with pentagastrin (4 micrograms/kg/min) and carbachol (0.8 microgram/kg/min) developed acute duodenal ulceration and hyperchlorhydria (68 +/- 6.1 mumol vs 12.5 +/- 0.3 mumol, mean +/- SEM, N = 10, P less than 0.001). Pretreatment with DL-cysteine, MMSB, DMSO, or allopurinol provided dose-dependent protection against this ulceration without significantly influencing the hyperchlorhydria. One percent solutions of these agents protected at least 20% of rats against ulceration. Five or 10% solutions of DL-cysteine, MMSB, or DMSO protected at least 70% of rats against ulceration and similar concentrations of allopurinol protected all animals. All rats having intramuscular reserpine (0.1 mg/kg) every day for six weeks developed chronic duodenal ulceration and hyperchlorhydria (52 +/- 3.1 mumol vs 13.1 +/- 0.7 mumol, mean +/- SEM, N = 10, P less than 0.001). Pretreatment with DL-cysteine, MMSB, DMSO, or allopurinol achieved dose-dependent protection against ulceration without significantly influencing the hyperchlorhydria. One percent solutions of DL-cysteine, MMSB, or DMSO protected at least 60% of rats against ulceration; however, a similar concentration of allopurinol protected 80% of animals. Five or 10% solutions of DL-cysteine, MMSB, or DMSO protected at least 80% of rats against ulceration and similar concentrations of allopurinol protected all rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Management of acute volvulus of the sigmoid colon: A new approach by percutaneous deflation and colopexy

Forty-one consecutive patients with acute sigmoid volvulus were prospectively randomized into 2 groups to compare percutaneous deflation prior to emergency tube decompression followed electively by colopexy with banding (n=20) versus emergency tube decompression followed electively by sigmoid colectomy (n=21). Of 21 patients subjected to tube decompression, the procedure was successful in 15 (71%). Emergency sigmoid colectomy was done in the remaining 6 patients and 3 of them died postoperatively. Percutaneous deflation enabled all patients (n=20) to have successful tube decompression without complications. Two of the patients (13%) who underwent elective sigmoid colectomy died postoperatively and another 2 developed wound infections, whereas colopexy by banding caused no mortality and only 1 patient (5%) developed a wound infection. Disconnection of the intravenous line, consumption of solid food, and discharge from the hospital were each effected at significantly (p <0.001) earlier postoperative times with colopexy than with sigmoid colectomy. Both of these elective procedures were equally effective in preventing recurrence of the volvulus. During 1 year of follow-up, colopexy was not observed to cause any abdominal pain or alteration in bowel habits. This study shows that percutaneous deflation of acute sigmoid volvulus is a rapid and safe method which enables successful sigmoidoscopic decompression with avoidance of emergency surgery and its high mortality rates. The study also shows that colopexy by banding is a simple elective procedure which overcomes the limitations of mesenteropexy and resectional surgery.

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Resumen Cuarenta y un pacientes con vólvulo agudo del sigmoide fueron prospectivamente randomizados en 2 grupos con el fin de comparar la deflación percutánea previa a la descompresión por sigmoidoscopia y tubo para el manejo de la situación de emergencia seguida de colopexia (n=20) versus la descompresión por medio de sigmoidoscopio y tubo para el manejo de la situación de emergencia seguida de resección electiva del colon sigmoide (n=21). De 21 pacientes sometidos a descompresión por medio de sigmoidoscopia y tubo, el procedimiento fue exitoso en 15 (71%). Se realizó resección de emergencia del colon sigmoide en los 6 pacientes restantes, y 3 de ellos murieron en el postoperatorio. La deflación percutánea permitió una exitosa descompresión por medio de sigmoidoscopia y tubo, sin complicaciones, en la totalidad de los casos (n=20). Dos de los pacientes (13%) sometidos a resección electiva del colon sigmoide murieron en el postoperatorio y otro desarrolló infección de la herida, en tanto que la colopexia no causó mortalidad y sólo un paciente (5%) desarrolló infección de la herida. La desconexión de la línea intravenosa, la ingesta de dieta sólida, y la salida del hospital se vieron significativamente acortadas (p<0.001), después de la colopexia en comparación la resección del colon sigmoide. Ambos procedimientos electivos aparecieron igualmente efectivos en cuanto a la prevención de recurrencia del vólvulo. En el curso de un seguimiento de un ano, la colopexia no causó síntomas de dolor abdominal ni alteración en el hábito intestinal.El presente estudio demuestra que la deflación percutánea del vólvulo agudo del sigmoide es un método rápido y seguro que hace posible la descompresión sigmoidoscópica evitando la cirugía de emergencia con su asociada alta mortalidad. El estudio también demuestra que la colopexia es un procedimiento electivo simple que supera las limitaciones de la mesenteropexia y la resección.

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Résumé Quarante et un patients ayant un volvulus aigu du côlon sigmoÏde ont été prospectivement randomisés en 2 groupes pour recevoir: (1) soit une décompression percutanée initiale, suivie d'une décompression par sigmoÏdoscopie et d'une colopexie effectuée par des bandelettes de Gore-Tex (n=20); (2) soit une décompression par sigmoÏdoscopie en urgence suivie de sigmoÏdectomie (n=21). Pour ces 21 patients, la décompression par coloscopie était un succès chez 15 (71%). Une sigmoÏdectomie a été effectuée en urgence chez les 6 autres patients dont 3 sont morts en période post-opératoire. Tous les patients ayant la décompression percutanée ont été ensuite décomprimés par coloscopie sans complications. Deux des 20 patients de ce groupe sont morts de leur colectomie et 2 ont eu un abcès de paroi. Dans le groupe ayant eu une colopexie, il n'y a eu aucune mort et un seul abcès de paroi (5%). Les patients du groupe avec colopexie ont eu besoin de perfusions intraveineuses moins longtemps, ont repris leur alimentation plus vite et ont quitté l'hôpital plus tôt que ceux de l'autre groups (p<0.001). Il n'y avait pas de différence dans la prévention des récidives. Pendant la période de surveillance d'un an, aucun patient dans le groupe avec colopexie ne s'est plaint de douleurs abdominales ou de troubles du transit.Cette étude démontre que la décompression percutanée du volvulus aigu du côlon sigmoÏde est rapide et sans danger: elle permet de décomprimer le côlon par coloscopie sans avoir recours à une chirurgie d'urgence à mortalité élevée. Elle montre aussi que la colopexie par bandelettes est simple et n'a ni les inconvénients, ni les limitations de la mésentéropexie ou de la résection.