Toxicity evaluation of manufactured CeO2 nanoparticles before and after alteration: combined physicochemical and whole-genome expression analysis in Caco-2 cells

Background

Engineered nanomaterials may release nanosized residues, by degradation, throughout their life cycle. These residues may be a threat for living organisms. They may be ingested by humans through food and water. Although the toxicity of pristine CeO₂ nanoparticles (NPs) has been documented, there is a lack of studies on manufactured nanoparticles, which are often surface modified. Here, we investigated the potential adverse effects of CeO₂ Nanobyk 3810™ NPs, used in wood care, and their residues, altered by light or acid.

Results

Human intestinal Caco-2 cells were exposed to residues degraded by daylight or in a medium simulating gastric acidity. Size and zeta potential were determined by dynamic light scattering. The surface structure and redox state of cerium were analyzed by transmission electronic microscopy (TEM) and X-ray absorption spectroscopy, respectively. Viability tests were performed in Caco-2 cells exposed to NPs. Cell morphology was imaged with scanning electronic microscopy. Gene expression profiles obtained from cells exposed to NPs before and after their alteration were compared, to highlight differences in cellular functions.No change in the cerium redox state was observed for altered NPs. All CeO₂ NPs suspended in the culture medium became microsized. Cytotoxicity tests showed no toxicity after Caco-2 cell exposure to these various NPs up to 170 μg/mL (24 h and 72 h). Nevertheless, a more-sensitive whole-gene-expression study, based on a pathway-driven analysis, highlighted a modification of metabolic activity, especially mitochondrial function, by altered Nanobyk 3810™. The down-regulation of key genes of this pathway was validated by qRT-PCR. Conversely, Nanobyk 3810™ coated with ammonium citrate did not display any adverse effect at the same concentration.

Conclusion

The degraded nanoparticles were more toxic than their coated counterparts. Desorption of the outside layer was the most likely cause of this discrepancy in toxicity. It can be assumed that the safe design of engineered nanoparticles could include robust protective layers conferring on them greater resistance to alteration during their life cycle.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-700) contains supplementary material, which is available to authorized users.     

Effects of TiO2 and Co3O4 Nanoparticles on Circulating Angiogenic Cells

Background and Aim

Sparse evidence suggests a possible link between exposure to airborne nanoparticles (NPs) and cardiovascular (CV) risk, perhaps through mechanisms involving oxidative stress and inflammation. We assessed the effects of TiO₂ and Co₃O₄ NPs in human circulating angiogenic cells (CACs), which take part in vascular endothelium repair/replacement.

Methods

CACs were isolated from healthy donors’ buffy coats after culturing lymphomonocytes on fibronectin-coated dishes in endothelial medium for 7 days. CACs were pre-incubated with increasing concentration of TiO₂ and Co₃O₄ (from 1 to 100 μg/ml) to test the effects of NP – characterized by Transmission Electron Microscopy – on CAC viability, apoptosis (caspase 3/7 activation), function (fibronectin adhesion assay), oxidative stress and inflammatory cytokine gene expression.

Results

Neither oxidative stress nor cell death were associated with exposure to TiO₂ NP (except at the highest concentration tested), which, however, induced a higher pro-inflammatory effect compared to Co₃O₄ NPs (p<0.01). Exposure to Co₃O₄ NPs significantly reduced cell viability (p<0.01) and increased caspase activity (p<0.01), lipid peroxidation end-products (p<0.05) and pro-inflammatory cytokine gene expression (p<0.05 or lower). Notably, CAC functional activity was impaired after exposure to both TiO₂ (p<0.05 or lower) and Co₃O₄ (p<0.01) NPs.

Conclusions

In vitro exposure to TiO₂ and Co₃O₄ NPs exerts detrimental effects on CAC viability and function, possibly mediated by accelerated apoptosis, increased oxidant stress (Co₃O₄ NPs only) and enhancement of inflammatory pathways (both TiO₂ and Co₃O₄ NPs). Such adverse effects may be relevant for a potential role of exposure to TiO₂ and Co₃O₄ NPs in enhancing CV risk in humans.     

The Spleen Responds to Intestinal Manipulation but Does Not Participate in the Inflammatory Response in a Mouse Model of Postoperative Ileus

Background

Postoperative ileus is characterized by a transient impairment of the gastrointestinal motility after abdominal surgery. The intestinal inflammation, triggered by handling of the intestine, is the main factor responsible for the prolonged dysmotility of the gastrointestinal tract. Secondary lymphoid organs of the intestine were identified as essential components in the dissemination of inflammation to the entire gastrointestinal tract also called field effect. The involvement of the spleen, however, remains unclear.

Aim

In this study, we investigated whether the spleen responds to manipulation of the intestine and participates in the intestinal inflammation underlying postoperative ileus.

Methods

Mice underwent Laparotomy (L) or Laparotomy followed by Intestinal Manipulation (IM). Twenty-four hours later, intestinal and colonic inflammation was assessed by QPCR and measurement of the intestinal transit was performed. Analysis of homeostatic chemokines in the spleen was performed by QPCR and splenic cell populations analysed by Flow Cytometry. Blockade of the egress of cells from the spleen was performed by administration of the Sphingosine-1-phosphate receptor 1 (S1P₁) agonist CYM-5442 10 h after L/IM.

Results

A significant decrease in splenic weight and cellularity was observed in IM mice 24 h post-surgery, a phenomenon associated with a decreased splenic expression level of the homeostatic chemokine CCL19. Splenic denervation restored the expression of CCL19 and partially prevented the reduction of splenocytes in IM mice. Treatment with CYM-5442 prevented the egress of splenocytes but did not ameliorate the intestinal inflammation underlying postoperative ileus.

Conclusions

Intestinal manipulation results in two distinct phenomena: local intestinal inflammation and a decrease in splenic cellularity. The splenic response relies on an alteration of cell trafficking in the spleen and is partially regulated by the splenic nerve. The spleen however does not participate in the intestinal inflammation during POI.     

Bactericidal Performance of Visible-Light Responsive Titania Photocatalyst with Silver Nanostructures

Background

Titania dioxide (TiO₂) photocatalyst is primarily induced by ultraviolet light irradiation. Visible-light responsive anion-doped TiO₂ photocatalysts contain higher quantum efficiency under sunlight and can be used safely in indoor settings without exposing to biohazardous ultraviolet light. The antibacterial efficiency, however, remains to be further improved.

Methodology/Principal Findings

Using thermal reduction method, here we synthesized silver-nanostructures coated TiO₂ thin films that contain a high visible-light responsive antibacterial property. Among our tested titania substrates including TiO₂, carbon-doped TiO₂ [TiO₂ (C)] and nitrogen-doped TiO₂ [TiO₂ (N)], TiO₂ (N) showed the best performance after silver coating. The synergistic antibacterial effect results approximately 5 log reductions of surviving bacteria of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Acinetobacter baumannii. Scanning electron microscope analysis indicated that crystalline silver formed unique wire-like nanostructures on TiO₂ (N) substrates, while formed relatively straight and thicker rod-shaped precipitates on the other two titania materials.

Conclusion/Significance

Our results suggested that proper forms of silver on various titania materials could further influence the bactericidal property.     

Tolerance of the vaginal vault to high-dose rate brachytherapy and concomitant chemo-pelvic irradiation: Long-term perspective

Aim/background

We sought to determine the tolerance level and complication rates of the vaginal vault to combined high-dose-rate intra-cavitary brachytherapy with concomitant chemo-radiotherapy.

Patients and methods

A retrospective review of medical records of all the patients who received definitive chemo-radiotherapy for cervical cancer between 1998 and 2002 was undertaken. The records were reviewed for doses and for radiation-associated early and late sequelae of the vagina, rectum and bladder. Cumulative biological effective dose was calculated for two reference vaginal surface points.

Results

Fifty patients were included. Average age at diagnosis was 54 years. Median follow-up was 59 months. There were no recorded instances of acute grade IV toxicity. Maximal high-dose-rate vaginal surface dose (upper central point) was 103 Gy, and maximal brachytherapy lateral surface dose was 70 Gy. Maximal cumulative biological effective dose for the lateral surface reference point was 465.5 Gy₃, and the maximal cumulative biological effective dose for the superior reference point was 878.6 Gy₃. There were no cases of vaginal necrosis or fistulas, and no cases of grade IV late vaginal, rectal or bladder toxicity. No correlation was found between the maximal vaginal surface dose and vaginal, rectal or bladder toxicity.

Conclusions

The maximal surface HDR brachytherapy dose of 103 Gy and the maximal cBED of 878.6 Gy₃ were not associated with fistula or necrosis or other grade 3–4 vaginal complications. Concomitant chemo-radiotherapy, including pelvic radiotherapy and high-dose-rate intracavitary brachytherapy, is relatively safe for cervical cancer patients.     

Neuroprotective effect of transplanted human embryonic stem cell-derived neural precursors in an animal model of multiple sclerosis

Background

Multiple sclerosis (MS) is an immune mediated demyelinating disease of the central nervous system (CNS). A potential new therapeutic approach for MS is cell transplantation which may promote remyelination and suppress the inflammatory process.

Methods

We transplanted human embryonic stem cells (hESC)-derived early multipotent neural precursors (NPs) into the brain ventricles of mice induced with experimental autoimmune encephalomyelitis (EAE), the animal model of MS. We studied the effect of the transplanted NPs on the functional and pathological manifestations of the disease.

Results

Transplanted hESC-derived NPs significantly reduced the clinical signs of EAE. Histological examination showed migration of the transplanted NPs to the host white matter, however, differentiation to mature oligodendrocytes and remyelination were negligible. Time course analysis of the evolution and progression of CNS inflammation and tissue injury showed an attenuation of the inflammatory process in transplanted animals, which was correlated with the reduction of both axonal damage and demyelination. Co-culture experiments showed that hESC-derived NPs inhibited the activation and proliferation of lymph node–derived T cells in response to nonspecific polyclonal stimuli.

Conclusions

The therapeutic effect of transplantation was not related to graft or host remyelination but was mediated by an immunosuppressive neuroprotective mechanism. The attenuation of EAE by hESC-derived NPs, demonstrated here, may serve as the first step towards further developments of hESC for cell therapy in MS.     

Influence of short-term glucocorticoid therapy on regulatory T cells in vivo

Background

Pre- and early clinical studies on patients with autoimmune diseases suggested that induction of regulatory T(T_reg) cells may contribute to the immunosuppressive effects of glucocorticoids(GCs).

Objective

We readdressed the influence of GC therapy on T_reg cells in immunocompetent human subjects and naïve mice.

Methods

Mice were treated with increasing doses of intravenous dexamethasone followed by oral taper, and T_reg cells in spleen and blood were analyzed by FACS. Sixteen patients with sudden hearing loss but without an inflammatory disease received high-dose intravenous prednisolone followed by stepwise dose reduction to low oral prednisolone. Peripheral blood T_reg cells were analyzed prior and after a 14 day GC therapy based on different markers.

Results

Repeated GC administration to mice for three days dose-dependently decreased the absolute numbers of T_reg cells in blood (100 mg dexamethasone/kg body weight: 2.8±1.8×10⁴ cells/ml vs. 33±11×10⁴ in control mice) and spleen (dexamethasone: 2.8±1.9×10⁵/spleen vs. 95±22×10⁵/spleen in control mice), which slowly recovered after 14 days taper in spleen but not in blood. The relative frequency of FOXP3⁺ T_reg cells amongst the CD4⁺ T cells also decreased in a dose dependent manner with the effect being more pronounced in blood than in spleen. The suppressive capacity of T_reg cells was unaltered by GC treatment in vitro. In immunocompetent humans, GCs induced mild T cell lymphocytosis. However, it did not change the relative frequency of circulating T_reg cells in a relevant manner, although there was some variation depending on the definition of the T_reg cells (FOXP3⁺: 4.0±1.5% vs 3.4±1.5%*; AITR⁺: 0.6±0.4 vs 0.5±0.3%, CD127^low: 4.0±1.3 vs 5.0±3.0%* and CTLA4+: 13.8±11.5 vs 15.6±12.5%; * p<0.05).

Conclusion

Short-term GC therapy does not induce the hitherto supposed increase in circulating T_reg cell frequency, neither in immunocompetent humans nor in mice. Thus, it is questionable that the clinical efficacy of GCs is achieved by modulating T_reg cell numbers.     

PEM Anchorage on Titanium Using Catechol Grafting

Background

This study deals with the anchorage of polyelectrolyte films onto titanium surfaces via a cathecol-based linker for biomedical applications.

Methodology

The following study uses a molecule functionalized with a catechol and a carboxylic acid: 3-(3,4-dihydroxyphenyl)propanoic acid. This molecule is anchored to the TiO₂ substrate via the catechol while the carboxylic acid reacts with polymers bearing amine groups. By providing a film anchorage of chemisorption type, it makes possible to deposit polyelectrolytes on the surface of titanium.

Principal Findings

Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), contact angle and atomic force microscopy (AFM) measurements show that the different steps of grafting have been successfully performed.

Conclusions

This method based on catechol anchorage of polyelectrolytes open a window towards large possibilities of clinical applications.     

Histological Changes in Kidney and Liver of Rats Due to Gold (III) Compound [Au(en)Cl2]Cl

Introduction

Development of novel metallodrugs with enhanced anti-proliferative potential and reduced toxicity has become the prime focus of the evolving medicinal chemistry. In this regards, gold (III) complexes with various ligands are being extensively investigated. In the current study renal and hepatic toxicity of a newly developed gold (III) compound [Au(en)Cl₂]Cl was assessed by histopathological evaluation of liver and kidney specimens of rats exposed to the compound.

Methods

Male rats (n = 42) weighing 200–250 gram were injected single, varying doses of gold (III) compound [(dichlorido(ethylenediamine)aurate((III)]chloride [Au(en)Cl₂]Cl in the acute toxicity component of the study. In the sub-acute toxicity part, a dose of 32.2 mg/kg (equivalent to 1/10 of LD50) was administered intraperitoneally for 14 consecutive days before sacrificing the animals. After autopsy, the renal and hepatic tissues were preserved in buffered formalin. Processing of the samples was followed by histopathological evaluation. The results were compared with the normal controls (n = 11).

Results

A dose of 32.2 mg/kg (1/10 of LD₅₀) revealed no renal tubular necrosis. The predominant histopathological finding was mild pyelitis, a prominence of eosinophils and mild congestion. The hepatic lesions comprised varying extents of ballooning degeneration with accompanying congestion and focal portal inflammation.

Conclusion

Gold (III) compound [Au(en)Cl₂]Cl causes minimal histological changes in kidney and liver of rats, reflecting its relative safety as compared to other clinically established antineoplastic drugs.     

MSC Therapy Attenuates Obliterative Bronchiolitis after Murine Bone Marrow Transplant

Rationale

Obliterative bronchiolitis (OB) is a significant cause of morbidity and mortality after lung transplant and hematopoietic cell transplant. Mesenchymal stromal cells (MSCs) have been shown to possess immunomodulatory properties in chronic inflammatory disease.

Objective

Administration of MSCs was evaluated for the ability to ameliorate OB in mice using our established allogeneic bone marrow transplant (BMT) model.

Methods

Mice were lethally conditioned and received allogeneic bone marrow without (BM) or with spleen cells (BMS), as a source of OB-causing T-cells. Cell therapy was started at 2 weeks post-transplant, or delayed to 4 weeks when mice developed airway injury, defined as increased airway resistance measured by pulmonary function test (PFT). BM-derived MSC or control cells [mouse pulmonary vein endothelial cells (PVECs) or lung fibroblasts (LFs)] were administered. Route of administration [intratracheally (IT) and IV] and frequency (every 1, 2 or 3 weeks) were compared. Mice were evaluated at 3 months post-BMT.

Measurements and Main Results

No ectopic tissue formation was identified in any mice. When compared to BMS mice receiving control cells or no cells, those receiving MSCs showed improved resistance, compliance and inspiratory capacity. Interim PFT analysis showed no difference in route of administration. Improvements in PFTs were found regardless of dose frequency; but once per week worked best even when administration began late. Mice given MSC also had decreased peribronchiolar inflammation, lower levels of hydroxyproline (collagen) and higher frequencies of macrophages staining for the alternatively activated macrophage (AAM) marker CD206.

Conclusions

These results warrant study of MSCs as a potential management option for OB in lung transplant and BMT recipients.     

Enhanced Photocatalytic Activity for H2 Evolution under Irradiation of UV–Vis Light by Au-Modified Nitrogen-Doped TiO2

Background Purpose

Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H₂ evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enhance the photocatalytic activity of TiO₂ by N doping and Au loading.

Methods

Au/N-doped TiO₂ photocatalysts were synthesized and successfully used for photocatalytic water splitting for H₂ evolution under irradiation of UV and UV–vis light, respectively. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and photoelectrochemical characterizations.

Results

DRS displayed an extension of light absorption into the visible region by doping of N and depositing with Au, respectively. PL analysis indicated electron-hole recombination due to N doping and an efficient inhibition of electron-hole recombination due to the loaded Au particles. Under the irradiation of UV light, the photocatalytic hydrogen production rate of the as-synthesized samples followed the order Au/TiO₂ > Au/N-doped TiO₂ > TiO₂ > N-doped TiO₂. While under irradiation of UV–vis light, the N-TiO₂ and Au/N-TiO₂ samples show higher H₂ evolution than their corresponding nitrogen-free samples (TiO₂ and Au/TiO₂). This inconsistent result could be attributed to the doping of N and the surface plasmonic resonance (SPR) effect of Au particles extending the visible light absorption. The photoelectrochemical characterizations further indicated the enhancement of the visible light response of Au/N-doped TiO₂.

Conclusion

Comparative studies have shown that a combination of nitrogen doping and Au loading enhanced the visible light response of TiO₂ and increased the utilization of solar energy, greatly boosting the photocatalytic activity for hydrogen production under UV–vis light.     

Dietary supplementation with probiotics improves hematopoiesis in malnourished mice

Background

Lactobacillus rhamnosus CRL1505 (Lr) administered during the repletion of immunocompromised-malnourished mice improves the resistance against intestinal and respiratory infections. This effect is associated with an increase in the number and functionality of immune cells, indicating that Lr could have some influence on myeloid and lymphoid cell production and maturation.

Objective

This study analyzed the extent of the damage caused by malnutrition on myeloid and lymphoid cell development in the spleen and bone marrow (BM). We also evaluated the impact of immunobiotics on the recovery of hematopoiesis affected in malnourished mice.

Methods

Protein malnourished mice were fed on a balanced conventional diet for 7 or 14 consecutive d with or without supplemental Lr or fermented goat''s milk (FGM). Malnourished mice and well-nourished mice were used as controls. Histological and flow cytometry studies were carried out in BM and spleen to study myeloid and lymphoid cells.

Results

Malnutrition induced quantitative alterations in spleen B and T cells; however, no alteration was observed in the ability of splenic B cells to produce immunoglobulins after challenge with LPS or CpG. The analysis of BM B cell subsets based on B220, CD24, IgM and IgD expression showed that malnutrition affected B cell development. In addition, BM myeloid cells decreased in malnourished mice. On the contrary, protein deprivation increased BM T cell number. These alterations were reverted with Lr or FGM repletion treatments since normal numbers of BM myeloid, T and B cells were observed in these groups.

Conclusions

Protein malnutrition significantly alters B cell development in BM. The treatment of malnourished mice with L. rhamnosus CRL1505 was able to induce a recovery of B cells that would explain its ability to increase immunity against infections. This work highlights the possibility of using immunobiotics to accelerate the recovery of lymphopoyesis in immunocompromised-malnourished hosts.     

Feasibility of Azacitidine Added to Standard Chemotherapy in Older Patients with Acute Myeloid Leukemia — A Randomised SAL Pilot Study

Introduction

Older patients with acute myeloid leukemia (AML) experience short survival despite intensive chemotherapy. Azacitidine has promising activity in patients with low proliferating AML. The aim of this dose-finding part of this trial was to evaluate feasibility and safety of azacitidine combined with a cytarabine- and daunorubicin-based chemotherapy in older patients with AML.

Trial Design

Prospective, randomised, open, phase II trial with parallel group design and fixed sample size.

Patients and Methods

Patients aged 61 years or older, with untreated acute myeloid leukemia with a leukocyte count of <20,000/µl at the time of study entry and adequate organ function were eligible. Patients were randomised to receive azacitidine either 37.5 (dose level 1) or 75 mg/sqm (dose level 2) for five days before each cycle of induction (7+3 cytarabine plus daunorubicine) and consolidation (intermediate-dose cytarabine) therapy. Dose-limiting toxicity was the primary endpoint.

Results

Six patients each were randomised into each dose level and evaluable for analysis. No dose-limiting toxicity occurred in either dose level. Nine serious adverse events occurred in five patients (three in the 37.5 mg, two in the 75 mg arm) with two fatal outcomes. Two patients at the 37.5 mg/sqm dose level and four patients at the 75 mg/sqm level achieved a complete remission after induction therapy. Median overall survival was 266 days and median event-free survival 215 days after a median follow up of 616 days.

Conclusions

The combination of azacitidine 75 mg/sqm with standard induction therapy is feasible in older patients with AML and was selected as an investigational arm in the randomised controlled part of this phase-II study, which is currently halted due to an increased cardiac toxicity observed in the experimental arm.

Trial Registration

This trial is registered at clinical trials.gov (identifier: {"type":"clinical-trial","attrs":{"text":"NCT00915252","term_id":"NCT00915252"}}NCT00915252).     

Bridging the gap between preclinical and clinical microbicide trials: blind evaluation of candidate gels in murine models of efficacy and safety

Background

Despite significant protection in preclinical studies, cellulose sulfate (CS) failed to protect women against HIV-1/2 and was associated with a trend toward increased HIV-1 acquisition in one of the clinical trials. These results highlight the need for preclinical tests more predictive of clinical outcomes. The objective of this study was to test coded vaginal gels, including CS, in murine models of safety and efficacy to determine the models'' utility for evaluating future products.

Methods

Four coded formulations, including 6% CS, 2% PRO 2000 and two placebo gels, were administered intravaginally to medroxyprogesterone-treated mice and their ability to prevent genital herpes (efficacy) or to alter the susceptibility to low dose HSV challenge (safety) was determined. Nonoyxnol-9 served as a positive toxicity control.

Results

CS and PRO 2000 significantly protected mice from genital herpes following infection with a laboratory or clinical isolate of HSV-2 introduced in buffer (p<0.001). However, protection was reduced when virus was introduced in seminal plasma. Moreover, mice were significantly more susceptible to infection with low doses of HSV-2 when challenged 12 h after the 7th daily dose of CS or nonoxynol-9 (p<0.05). The increased susceptibility was associated with alterations in epithelial architecture.

Conclusions

CS prevented genital herpes when present at the time of viral challenge, but increased the rate of infection when gel was applied daily for 7 days with a vaginal wash prior to viral inoculation. The findings presumably reflect altered epithelial architecture, which may have contributed to the trend towards increased HIV observed clinically.     

Role of Visible Light-Activated Photocatalyst on the Reduction of Anthrax Spore-Induced Mortality in Mice

Background

Photocatalysis of titanium dioxide (TiO₂) substrates is primarily induced by ultraviolet light irradiation. Anion-doped TiO₂ substrates were shown to exhibit photocatalytic activities under visible-light illumination, relative environmentally-friendly materials. Their anti-spore activity against Bacillus anthracis, however, remains to be investigated. We evaluated these visible-light activated photocatalysts on the reduction of anthrax spore-induced pathogenesis.

Methodology/Principal Findings

Standard plating method was used to determine the inactivation of anthrax spore by visible light-induced photocatalysis. Mouse models were further employed to investigate the suppressive effects of the photocatalysis on anthrax toxin- and spore-mediated mortality. We found that anti-spore activities of visible light illuminated nitrogen- or carbon-doped titania thin films significantly reduced viability of anthrax spores. Even though the spore-killing efficiency is only approximately 25%, our data indicate that spores from photocatalyzed groups but not untreated groups have a less survival rate after macrophage clearance. In addition, the photocatalysis could directly inactivate lethal toxin, the major virulence factor of B. anthracis. In agreement with these results, we found that the photocatalyzed spores have tenfold less potency to induce mortality in mice. These data suggest that the photocatalysis might injury the spores through inactivating spore components.

Conclusion/Significance

Photocatalysis induced injuries of the spores might be more important than direct killing of spores to reduce pathogenicity in the host.     

The effect of titanium dioxide nanoparticles on pulmonary surfactant function and ultrastructure

Background

Pulmonary surfactant reduces surface tension and is present at the air-liquid interface in the alveoli where inhaled nanoparticles preferentially deposit. We investigated the effect of titanium dioxide (TiO₂) nanosized particles (NSP) and microsized particles (MSP) on biophysical surfactant function after direct particle contact and after surface area cycling in vitro. In addition, TiO₂ effects on surfactant ultrastructure were visualized.

Methods

A natural porcine surfactant preparation was incubated with increasing concentrations (50-500 μg/ml) of TiO₂ NSP or MSP, respectively. Biophysical surfactant function was measured in a pulsating bubble surfactometer before and after surface area cycling. Furthermore, surfactant ultrastructure was evaluated with a transmission electron microscope.

Results

TiO₂ NSP, but not MSP, induced a surfactant dysfunction. For TiO₂ NSP, adsorption surface tension (γ_ads) increased in a dose-dependent manner from 28.2 ± 2.3 mN/m to 33.2 ± 2.3 mN/m (p < 0.01), and surface tension at minimum bubble size (γ_min) slightly increased from 4.8 ± 0.5 mN/m up to 8.4 ± 1.3 mN/m (p < 0.01) at high TiO₂ NSP concentrations. Presence of NSP during surface area cycling caused large and significant increases in both γ_ads (63.6 ± 0.4 mN/m) and γ_min (21.1 ± 0.4 mN/m). Interestingly, TiO₂ NSP induced aberrations in the surfactant ultrastructure. Lamellar body like structures were deformed and decreased in size. In addition, unilamellar vesicles were formed. Particle aggregates were found between single lamellae.

Conclusion

TiO₂ nanosized particles can alter the structure and function of pulmonary surfactant. Particle size and surface area respectively play a critical role for the biophysical surfactant response in the lung.     

A novel dynamic field-matching technique for treatment of patients with para-aortic node-positive cervical cancer: Clinical experience

Aim

To report outcomes for patients with para-aortic lymph node positive cervical cancer treated with a dynamic field-matching technique.

Background

PET staging of cervical cancer has increased identification of patients with para-aortic lymph node metastasis. IMRT enables dose escalation in this area, but matching IMRT fields with traditional whole pelvis fields presents a challenge.

Materials and methods

From 2003 to 2012, 20 patients with cervical cancer and para-aortic lymph node metastasis were treated utilizing the dynamic field-matching technique. As opposed to single-isocenter half-beam junction techniques, this technique employs wedge-shaped dose junctions for the abutment of fields. We reviewed the records of all patients who completed treatment with the technique and abstracted treatment, toxicity, and disease-related outcome data for analysis.

Results

Median prescribed dose to the whole pelvis field was 45 Gy and para-aortic IMRT field 50.4 Gy. All but 3 patients underwent HDR (13 pts) or LDR (4 pts) brachytherapy. All patients developed lower GI toxicity; 10 grade 1, 9 grade 2, and 1 grade 4 (enterovaginal fistula). Median DFS was 12.4 months with 1 and 2-year DFS 60.0% and 38.1%. One-year OS was 83.7% and 2-year OS, 64.4%. A total of 10 patients developed recurrence; none occurred at the matched junction.

Conclusions

The dynamic field-matching technique provides a means for joining conventional whole pelvis fields and para-aortic IMRT fields that substantially reduces dose deviations at the junction due to field mismatch. Treatment with the dynamic matching technique is simple, effective, and tolerated with no apparent increase in toxicity.     

In Vivo Study of Spherical Gold Nanoparticles: Inflammatory Effects and Distribution in Mice

Objectives

Gold nanoparticles (AuNPs) of 21 nm have been previously well characterized in vitro for their capacity to target macrophages via active uptake. However, the short-term impact of such AuNPs on physiological systems, in particular resident macrophages located in fat tissue in vivo, is largely unknown. This project investigated the distribution, organ toxicity and changes in inflammatory cytokines within the adipose tissue after mice were exposed to AuNPs.

Methods

Male C57BL/6 mice were injected intraperitoneally (IP) with a single dose of AuNPs (7.85 μg AuNPs/g). Body weight and energy intake were recorded daily. Tissues were collected at 1 h, 24 h and 72 h post-injection to test for organ toxicity. AuNP distribution was examined using electron microscopy. Proinflammatory cytokine expression and macrophage number within the abdominal fat pad were determined using real-time PCR.

Results

At 72 hours post AuNP injection, daily energy intake and body weight were found to be similar between Control and AuNP treated mice. However, fat mass was significantly smaller in AuNP-treated mice. Following IP injection, AuNPs rapidly accumulated within the abdominal fat tissue and some were seen in the liver. A reduction in TNFα and IL-6 mRNA levels in the fat were observed from 1 h to 72 h post AuNP injection, with no observable changes in macrophage number. There was no detectable toxicity to vital organs (liver and kidney).

Conclusion

Our 21 nm spherical AuNPs caused no measurable organ or cell toxicity in mice, but were correlated with significant fat loss and inhibition of inflammatory effects. With the growing incidence of obesity and obesity-related diseases, our findings offer a new avenue for the potential development of gold nanoparticles as a therapeutic agent in the treatment of such disorders.     

Gemcitabine-mediated radiosensitization of human soft tissue sarcoma

Background/Purpose

Local and systemic control of soft tissue sarcoma (STS) remains a clinical challenge, particularly for retroperitoneal, deep truncal, or advanced extremity disease. 2′,2′-Difluoro-2′-deoxycytidine (gemcitabine) is a potent radiosensitizer in many tumor types, but it has not been studied in human STS. The purpose of this study was to determine the radiosensitizing potential of gemcitabine in preclinical models of human STS.

Materials and Methods

The in vitro radiosensitizing activity of gemcitabine was assessed with clonogenic survival assay on three human STS cell lines: SK-LMS-1 (leiomyosarcoma), SW-872 (liposarcoma), and HT-1080 (fibrosarcoma). Cell cycle distribution was determined using dual-channel flow cytometry. The in vivo radiosensitizing activity of gemcitabine was assessed with subcutaneous SK-LMS-1 nude mice xenografts. Tumor-bearing mice were treated with concurrent weekly gemcitabine and fractionated daily radiotherapy (RT) (2 Gy daily) for 3 weeks (a total dose of 30 Gy).

Results

The 50% inhibitory concentration (IC₅₀) of gemcitabine for the human STS cell lines ranged from 10 to 1000 nM. Significant in vitro radiosensitization was demonstrated in all three human STS cell lines using gemcitabine concentrations at and below the IC₅₀. Maximal radiosensitization was associated with accumulation of cells in early S-phase. SK-LMS-1 xenografts displayed significant tumor growth delay with combined gemcitabine and RT compared to either treatment alone. Treatment related toxicity was greatest in the gemcitabine plus RT arm, but remained at an acceptable level.

Conclusions

Gemcitabine is a potent radiosensitizer in preclinical models of human STS. Clinical trials combining gemcitabine and RT in human STS are warranted.