Mitochondrial Lipid Peroxidation Is Responsible for Ferroptosis.

Ferroptosis induced by erastin (an inhibitor of cystine transport) and butionine sulfoximine (an inhibitor of glutathione biosynthesis) was prevented by the mitochondria-targeted antioxidants SkQ1 and MitoTEMPO. These effects correlate with the prevention of mitochondrial lipid peroxidation, which precedes cell death. Methylene blue, a redox agent that inhibits the production of reactive oxygen species (ROS) in complex I of the mitochondrial electron transport chain, also inhibits ferroptosis and mitochondrial lipid peroxidation. Activation of ROS production in complex I with rotenone in the presence of ferrous iron stimulates lipid peroxidation in isolated mitochondria, while ROS produced by complex III are ineffective. SkQ1 and methylene blue inhibit lipid peroxidation. We suggest that ROS formed in complex I promote mitochondrial lipid peroxidation and ferroptosis.

Methylene blue-mediated Photodynamic Therapy in human retinoblastoma cell lines.

Retinoblastoma is a malignant tumor of the retinal precursor cells and one of the rarest types of pediatric tumor, often occurring in the earliest years of life. Symptoms are conditioned by tumor size and location; one of the most recurrent symptoms is a white reflex in the pupillary area, called leukocoria or cat's eye reflex. In the present work, we studied the in vitro effectiveness of Photodynamic treatment (Pdt) in two types of human retinoblastoma, Y79 and WERI-Rb cell lines, using methylene blue (MB), a photosensitizer (PS) from the phenothiazine group. The two cell lines were incubated with varying concentrations of MB (3, 7, 10, 15, 20, 25, 30, 40, and 50 µM), in the absence of light (dark cytotoxicity) and, in the presence of 664 nm laser light (phototoxicity) with fluences of 1, 1.5, 3, 5, 7, 10, and 15 J/cm2. The Y79 cell line showed higher cellular uptake values for MB than the WERI-Rb cell line. After three hours of incubation, the Y79 and WERI-Rb took up 48% and 34% of the total photosensitizer present in the medium, respectively. Using MTT assay, the results showed that the Y79 cell line was more affected by the photo treatment as demonstrated by the combination of MB concentration and light doses compared with WERI-Rb cell line. The results were correlated with the more pronounced singlet oxygen emission observed in Y79 cells. While MB does show efficacy for eradication of retinoblastoma in vitro, only studies in appropriate animal models will reveal whether the selectivity of photokilling at tolerable drug and light doses is sufficient to suggest clinical trials.

Expanding the ZIFs Repertoire for Biological Applications with the Targeted Synthesis of ZIF-20 Nanoparticles.

Owing to their facile synthesis, tailorable porosity, diverse compositions, and low toxicity, zeolitic imidazolate framework (ZIF) nanoparticles (NPs) have emerged as attractive platforms for a variety of biologically relevant applications. To date, a small subset of ZIFs representing only two topologies and very few linker chemistries have been studied in this realm. We seek to expand the bio-design space for ZIF NPs through the targeted synthesis of a hierarchically complex ZIF based on two types of cages, ZIF-20, with lta topology. This study demonstrates the rapid synthesis and size tunability of ZIF-20 particles across the micro and nanoregimes via microwave heating and the use of a modulating agent. To evaluate the utility of ZIF particles for biological applications, we examine their stability in biologically relevant media and demonstrate biocompatibility with A549 human epithelial cells. Further, the ability to encapsulate and release methylene blue, a therapeutic and bioimaging agent, is validated. Importantly, ZIF-20 NPs display a unique behavior relative to previously studied ZIFs based on their specific structural and chemical features. This finding highlights the need to expand the design space across the broader ZIFs family, to exploit a wider range of relevant properties for biological applications and beyond.

Application of fluorescein combined with methylene blue in sentinel lymph node biopsy of breast cancer.

Sentinel lymph node biopsy (SLNB) for axillary lymph node staging in early breast cancer has been widely recognized. The combination of radio-colloids and dye method is the best method recognized. The reagents and equipment required in the process of the combined method are complex and expensive, so there are certain restrictions in the use of primary medical institutions. As a new tracer, fluorescent tracer technology has attracted much attention. We aimed to evaluate the feasibility and safety of fluorescein for SLNB in breast cancer. In this study, a total of 123 patients with breast cancer were divided into group A (n = 67) and group B (n = 56). The efficacy of Indocyanine green (ICG) combined with methylene blue (group A) and fluorescein combined with methylene blue (group B) in SLNB of breast cancer was compared, complications were observed at the same time. No local or systemic reactions were observed in the two groups. In group A, Sentinel lymph nodes of breast cancer were detected in 63 patients, with a detection rate of 94.0% (63/67), a false-negative rate of 7.5% (4/53). In group B, Sentinel lymph nodes of breast cancer were detected in 52 patients, with a detection rate of 92.9% (52/56), a false-negative rate of 7.5% (3/40). There was no significant difference in biopsy results between the two groups. This prospective clinical study suggests that SLNB using fluorescein and ultraviolet LED light is feasible in breast cancer patients. No adverse reactions were observed in this study, but larger studies are needed to properly assess the adverse reaction rate.

Hybrids of Upconversion Nanoparticles and Silver Nanoclusters Ensure Superior Bactericidal Capability via Combined Sterilization.

It is highly desired to develop new antibacterial agents with superior bactericidal efficiency for minimizing the damage to biological cells. We developed a combined antibacterial nanohybrid exhibiting a superb bactericidal effect and excellent biocompatibility by integrating upconversion nanoparticles (UCNPs) with silver nanoclusters (AgNCs). UCNPs and methylene blue (MB) molecules were encapsulated with silica microspheres via microemulsion, with MB as the photosensitizer. Silver ions (Ag+) were reduced by amino groups on the surface of silica spheres, wherein silver nanoclusters (AgNCs) were formed in situ to produce the nanohybrid, UCNPs@SiO2(MB)@AgNCs. UCNPs emit visible light at 655 nm under excitation by near-infrared radiation (NIR, 980 nm). MB absorbs the emission from UCNPs to generate toxic singlet oxygen (1O2), which leads to the apoptosis of bacteria cells. Meanwhile, silver ions released from AgNCs destroy the bacteria membrane structure. Upon NIR irradiation at 980 nm for 10 min, 8.33 µg mL-1 nanohybrid results in a 100% killing rate for both Gram-positive S. aureus (+) and Gram-negative E. coli (-).

Fabrication, characterization and evaluation of myricetin adsorption onto starch nanoparticles.

Myricetin (MY) is a natural antioxidant flavonoid with a variety of biological activities. However, extremely low water solubility, bioavailability, and easy degradation, restrict their application. Recently, increasing interest in starch nanoparticles as a new kind of biocompatible renewable polymer in applications like nanocarriers. This work was to fabricate MY adsorption onto tapioca starch nanoparticles (TSNPs) and evaluate their biological activities. The adsorption mechanism, loading amount, antioxidative capacity, and in vitro release of the loaded MY were also analyzed. The adsorption kinetics and adsorption equilibrium were best explained by a pseudo-second-order model and Freundlich isotherms, respectively. Based on the thermodynamic parameters, adsorption was found to be a spontaneous and exothermic process with a decrease in entropy. MY possessed a maximum equilibrium adsorption capacity of 453 ± 8.07 mg/g. Low cytotoxicity were obtained as described by methylene blue assay, and a sustained release of loaded MY was observed in stimulated gastric (pH 2.0) and intestinal (pH 7.0) fluids. Additionally, the rate of clearance of DPPH free radicals was increased by the adsorption of MY onto TSNPs, which was confirmed by the lower value of 50 % inhibitory concentration (IC50).

Methylene Blue Absorption in Sentinel Lymph Node Biopsy for Early Breast Cancer after Neoadjuvant Chemotherapy.

INTRODUCTION: Chemotherapy is claimed to cause lymphatic drainage damage because of the tumor cell's apoptosis process. This event might cause decreased marker (radioactive solution and/or blue dye) absorption on sentinel lymph nodes (SLN). In this study, the researchers used methylene blue only and wished to evaluate the methylene blue absorption of the SLNB procedure on early-stage breast-cancer patients after neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: The method used was the historical cohort study conducted from 2016-2019 in Indonesia. Samples were collected from 117 patients of stage I and II breast cancer with clinically negative axillary lymph nodes, who were then grouped into post-NAC and no-NAC (control group), in which SLNB procedures were conducted on the two groups by using single-method methylene blue. The results of methylene blue absorption were then analyzed by the Chi-square hypothesis test. RESULTS: From the total of 564 early-stage patients who were referred to surgical oncologists, 117 patients were found to meet criteria of inclusion, consisting of the control group (52 patients) and the post-NAC group (65 patents). Of 65 patients who had undergone NAC treatment and SLNB procedure, it was found that 40 patients (61.5%) showed positive blue SLN. Of 52 pre-NAC breast-cancer patients, it was found that 47 patients (90.4%) showed methylene blue absorption on SLN with the p-value of 0.000 (P<0.05, significant). The relative risk value amounted to 0.522. Post-NAC patients had a tendency of decreased absorption of methylene blue. CONCLUSION: Neoadjuvant chemotherapy can cause the decrease of methylene blue absorption on SLNB procedure.

Low-cost Fluorescein as an Alternative to Radio-colloid for Sentinel Lymph Node Biopsy-a Prospective Validation Study in Early Breast Cancer.

BACKGROUND: Sentinel lymph node biopsy (SLNB) using radio-pharmaceutical (RP) and a blue dye is gold standard for axillary staging in clinically node-negative early breast cancer. High costs and limited availability of RP and/or gamma probe are major deterrents in performing SLNB in developing countries. Fluorescence-guided SLNB can obviate the need for RP and gamma probe. Fluorescein is an inexpensive fluorescent lymphatic tracer. In this study, we compared SLN identification rate (SLN-IR) and false negative rates (FNR) of fluorescein-guided SLNB and radio-guided SLNB using 99mTc-Sulfur-colloid, in isolation, or in combination with methylene blue dye (MBD). METHODS: Sixty-five cN0 early and large operable breast cancer patients underwent validation SLNB using fluorescein (and blue LED light), 99mTc-Sulfur-colloid (and gamma probe) and MBD. Inj Fluorescein 4% was injected, 1 ml each peri-tumoral and sub-areolar five minutes before axillary incision. Axillary dissection was performed irrespective of SLNB histology. The SLN-IR and FNR with various tracers and their combinations were compared. RESULTS: The mean number of SLNs identified was 3.5 ± 1.8 (range 1-6). The SLN-IR using RP alone was 94%, fluorescein alone was 92%, and MBD alone was 82%. The SLN-IR using fluorescein plus MBD combination was 95.4%, compared to 97% using MBD plus RP combination. FNR was 6.3% using fluorescein plus MBD, as well as RP plus MBD combinations. CONCLUSIONS: SLN-IR of > 90% and SLN-FNR of < 10% using fluorescein plus MBD combination are in acceptable range, and are comparable to that of RP plus MBD combination. Fluorescein can replace RP for performing SLNB, in combination with MBD.

Indocyanine Green Fluorescence Versus Blue Dye or Radioisotope Regarding Detection Rate of Sentinel Lymph Node Biopsy and Nodes Removed in Breast Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: Either blue dye (BD) or radioisotope (RI) is mainly used for sentinel lymph node biopsy (SLNB) in breast cancer patients. Unlike the BD, RI has lower false-negative rate of SLNB. However, its lymphoscintigraphy, difficulty in preoperative injection, and undetected sentinel lymph nodes in some cases cause surgeons to rely only on BD. Currently, indocyanine green (ICG) fluorescence method (ICG-SLNB) is increasingly used as an alternative to the conventional mapping methods in many centers. This systematic review compared ICG with the conventional method of BD or RI in terms of detection rate of SLNB and the number of sentinel lymph nodes (SLNs) removed in. METHODS:   We searched all relevant studies published between January 2000 and October 2019. All data on for evaluation of SLN detection rate, number of SLNs removed per patient, and tumor positive rate of SLNB were extracted. RESULTS: A total of 30 studies, including 4,216 SLN procedures were retrieved. There was a statistically significant difference between ICG and BD method in terms of SLN detection rate (OR, 6.73; 95% CI, 4.20-10.78). However, there was no significant difference between ICG and RI in this regard (OR, 0.90; 95% CI, 0.40-2.03). The number of SLNs removed per patient were 2.35 (1.46-5.4), 1.92 (1.0-3.64), and 1.72 (1.35-2.08) for ICG, BD, and RI, respectively. Only in 8 studies, the tumor positive rates in SLNB could be analyzed (ICG, 8.5-20.7%; BD, 12.7-21.4%; RI, 11.3-16%). CONCLUSION: ICG-SLNB could be an additional or an alternative method for axillary node mapping in breast cancer.
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Usefulness of urinary glycosaminoglycans assay for a mucopolysaccharidosis-specific screening.

BACKGROUND: Mucopolysaccharidoses (MPS), a group of inherited metabolic disorders characterized by the accumulation of glycosaminoglycans, can be diagnosed early through newborn screening programs. Establishing newborn screening in Morocco is a challenging task for multiple economic and social reasons. Screening in a Moroccan population using 1,9-dimethylmethylene blue urinary glycosaminoglycan (GAG) assays may allow for an earlier diagnosis of MPS. We studied the feasibility of implementing screening in Moroccan children as an alternative to national newborn screening. We determined the reference ranges for GAGs in the Moroccan population, their stability during transport, the effectiveness of this test as a screening procedure for MPS in patients, and its use as a screening test for MPS in the Imssouane region, where the rate of consanguineous marriage is 38%. METHODS: Using dimethylmethylene blue assays, urine samples of 47 MPS patients were analyzed, together with urine samples from healthy controls (n = 368, age ranging from 1 month to 25 years), and from Imssouane region children (n = 350, age ranging from 6 months to 24 month). Precision, linearity, recovery, limits, and stability were tested. RESULTS: Urinary GAGs reference values are age and ethnicity dependent. The validation parameters established displayed great precision and accuracy leading to recoveries according to internationally accepted values for bioanalytical methods. Urinary GAGs were stable for a maximum of 7 weeks at 40 °C. Screening of Imssouane children resulted in the detection of a 6-month-old child, diagnosed with MPS I. CONCLUSIONS: Our results demonstrate the usefulness of quantifying glycosaminoglycans for early screening of MPS.

Combining lipoic acid to methylene blue reduces the Warburg effect in CHO cells: From TCA cycle activation to enhancing monoclonal antibody production.

The Warburg effect, a hallmark of cancer, has recently been identified as a metabolic limitation of Chinese Hamster Ovary (CHO) cells, the primary platform for the production of monoclonal antibodies (mAb). Metabolic engineering approaches, including genetic modifications and feeding strategies, have been attempted to impose the metabolic prevalence of respiration over aerobic glycolysis. Their main objective lies in decreasing lactate production while improving energy efficiency. Although yielding promising increases in productivity, such strategies require long development phases and alter entangled metabolic pathways which singular roles remain unclear. We propose to apply drugs used for the metabolic therapy of cancer to target the Warburg effect at different levels, on CHO cells. The use of α-lipoic acid, a pyruvate dehydrogenase activator, replenished the Krebs cycle through increased anaplerosis but resulted in mitochondrial saturation. The electron shuttle function of a second drug, methylene blue, enhanced the mitochondrial capacity. It pulled on anaplerotic pathways while reducing stress signals and resulted in a 24% increase of the maximum mAb production. Finally, the combination of both drugs proved to be promising for stimulating Krebs cycle activity and mitochondrial respiration. Therefore, drugs used in metabolic therapy are valuable candidates to understand and improve the metabolic limitations of CHO-based bioproduction.

Development of thermosensitive hydrogel containing methylene blue for topical antimicrobial photodynamic therapy.

Due to the emergence of antibiotic resistance, antimicrobial photodynamic therapy (aPDT) has recently been demonstrated as a promising alternative to antibiotics to treat wound infections caused by multidrug-resistant (MDR) pathogens. This study aimed to evaluate the bacterial killing efficiency of aPDT mediated by methylene blue (MB) loaded thermosensitive hydrogels against methicillin-resistant Staphylococcus aureus (MRSA). Box-Behnken Design method was employed to investigate the impacts of the polymer compositions, Poloxamer 407, Poloxamer 188 and Carbopol 934P, on the gelation temperature (Tsol-gel) and release rate of MB. The viscosity and in vitro bacterial killing efficiency of three selected formulations with Tsol-gel ranged 25-34 °C and MB release in 2 h (the incubation time used for aPDT experiment) ≥ 70%, were assessed. The viscosity was found to increase with increasing P407 content and increasing total gel concentration. In the in vitro aPDT experiment, all tested MB-hydrogels demonstrated >2.5 log10 colony forming unit (CFU) reduction against three clinical relevant MRSA strains. Interestingly, the bacterial reduction increased with decreasing amount of gel added (reduced MB concentration). This was possibly attributed to the increased viscosity at higher gel concentration reducing the diffusion rate of released MB towards bacterial cells leading to reduced aPDT efficiency. In summary, aPDT with the thermosensitive MB hydrogel formulations is a promising treatment strategy for wound infections.

Synthesis and application of V2O5-CeO2 nanocomposite catalyst for enhanced degradation of methylene blue under visible light illumination.

Methylene blue dye is among the toxic, mutagenic, and carcinogenic pollutants. Hence, its treatment via photocatalytic degradation is an important remediation method for the sake of a healthy environment. Herein, the V2O5-CeO2 nanocomposite catalysts were synthesized via a simple precipitation-thermal decomposition approach and used for the photodegradation of methylene blue in the presence of H2O2 as an effective electron scavenger under visible light illumination. The nanocomposite catalysts were systematically characterized to investigate the effects of V2O5 with the aids of X-ray, morphology, light absorption, catalytic activity, and charge transfer properties of the nanocomposite catalysts. The VC-2 nanocomposite prepared with NH4VO3:CeO2 molar ratios at 0.15:1 was found to be the best efficient catalyst where ≥98% of methylene blue was degraded within 25 min irradiation time. From the kinetics analysis, its rate constant was found to be higher than those of the pure V2O5 and CeO2 catalysts by a factor of 12.0 and 13.5, respectively. The plausibly mechanistic elucidation of charge transfer and utilization of reactive species are conspicuous allegations of the combined effects of the nanocomposite catalyst, H2O2 sacrificial agent, and visible light for the photodegradation of the dye.

A self-powered delivery substrate boosts active enzyme delivery in response to human movements.

Stimulated drug releases in response to human movements are highly appealing in medical therapy and various daily uses. However, the design of a mechanically responsive substrate that presents high delivery capacities and can also preserve the activities of sensitive molecules such as enzymes is still challenging. Taking advantage of the recent development in effective piezoelectric flexible films and in molecular delivery devices, we propose a composite delivery substrate that preserves enzyme activities and enhances molecular delivery in response to human movements such as finger presses or massages. The substrate is achieved by combining two parts, which are the energy converting unit and the molecular loading and releasing unit. The energy converting unit is a piezoelectric-dielectric flexible composite film that produces enhanced electricity and preserves the electricity longer compared to a pure piezoelectric polymer. The molecular delivery unit is a layer-by-layer multilayer containing mesoporous silica particles that are assembled at pH 9 but used in neutral solutions. The releases of molecules including small molecules, peptides, and proteins are all accelerated in response to finger presses irrespective of the signs or densities of their charges. More importantly, the enzyme CAT preserves its activity after release from the composite substrates, meaning that the CAT-loaded (PAH/MS)n(PAH/DAS)n@rGO-TFB/PVDF-HFP composite substrate holds promise as a self-powered soothing pad that effectively removes residue H2O2.

The Application of 1% Methylene Blue Dye As a Single Technique in Breast Cancer Sentinel Node Biopsy.

In this study, we injected 1% methylene blue dye (MBD) into the subareolar or peritumoral space of the breast. In the case of breast conserving surgery (BCS), a separate incision in the lower axilla hairline was made to find the sentinel nodes (SNs). In mastectomy, the SNs were identified through the same mastectomy incision. The SNs were described as blue nodes or nodes with lymphatic blue channels. An anatomical landmark in the axilla was used to facilitate SNs identification. The SNs metastases were evaluated by intraoperative frozen section analysis and histopathology examination as it is a gold standard. Here, we described the MBD as the lone technique in breast cancer sentinel node biopsy (SNB) which could be useful when radioisotope tracer or patent or isosulfan blue dye (PBD) cannot be provided.

Screening sediment samples used as anolytes in microbial fuel cells for microbial electron transfer activity using DREAM assay.

OBJECTIVE: The dye reduction-based electron-transfer activity monitoring (DREAM) assay was employed to screen sediment and wastewater samples functioning as anolytes in a microbial fuel cell (MFC) for their microbial electron transfer activity. RESULTS: Electron transfer to redox dyes from microbial activity reduced the dyes and the resulting extent of reduction was measured as DREAM assay coefficient. Methylene blue was decolourised, while resazurin underwent florigenic change from blue to pink to colourless upon formation of resorufin and dihydroxyresorufin. DREAM assay coefficient conformed to power density obtained in the MFC. A correlation was observed between chemical oxygen demand of the sample and the DREAM coefficient (+ 0.934) and also between DREAM coefficient and power density generated (+ 0.976). Highest DREAM coefficient and power density was observed for activated sludge. CONCLUSIONS: The DREAM assay is a rapid, sensitive and low-cost method to assess microbial electron transfer activity for inocula used as anolytes in a MFC.

Combining dietary phenolic antioxidants with polyvinylpyrrolidone: transparent biopolymer films based on p-coumaric acid for controlled release.

Polyvinylpyrrolidone (PVP) has probably been one of the most utilized pharmaceutical polymers with applications ranging from a blood plasma substitute to nanoparticle drug delivery, since its synthesis in 1939. It is a highly biocompatible, non-toxic and transparent film forming polymer. Although high solubility of PVP in aqueous environment is advantageous, it still poses several problems for some applications in which sustained targeting and release are needed or hydrophobic drug inclusion and delivery systems are to be designed. In this study, we demonstrate that a common dietary phenolic antioxidant, p-coumaric acid (PCA), can be combined with PVP covering a wide range of molar ratios by solution blending in ethanol, forming new transparent biomaterial films with antiseptic and antioxidant properties. PCA not only acts as an effective natural plasticizer but also establishes H-bonds with PVP increasing its resistance to water dissolution. PCA could be released in a sustained manner up to a period of 3 days depending on the PVP/PCA molar ratio. Sustained drug delivery potential of the films was studied using methylene blue and carminic acid as model drugs, indicating that the release can be controlled. Antioxidant and remodeling properties of the films were evaluated in vitro by free radical cation scavenging assay and in vivo on a murine model, respectively. Furthermore, the material resorption of films was slower as PCA concentration increased, as observed from the in vivo full-thickness excision model. Finally, the antibacterial activity of the films against common pathogens such as Escherichia coli and Staphylococcus aureus and the effective reduction of inflammatory agents such as matrix metallopeptidases were demonstrated. All these properties suggest that these new transparent PVP/PCA films can find a plethora of applications in pharmaceutical sciences including skin and wound care.

Archival May-Grünwald-Giemsa-Stained Bone Marrow Smears Are an Eligible Source for Molecular DNA Research.

Biobanking is increasingly important in studying complex heterogeneous diseases. Therefore, it is essential to ensure the sample quality after long-term storage for reliable downstream analyses. The Clinical Biobank of the Jessa Hospital and the University Biobank Limburg (UBiLim) hold a continuously growing collection of hematological samples, including May-Grünwald-Giemsa (MGG)- and Perls' Prussian Blue (PPB)-stained bone marrow (BM) smears, stored at room temperature (RT) for up to 20 years. In this study, we investigated the effect of short- and long-term storage on the quality of DNA and RNA extracted from these BM smears to assess their fitness-for-purpose in downstream molecular applications, including agarose gel electrophoresis, bio-analyzer analysis, quantitative polymerase chain reaction (qPCR), and targeted next-generation sequencing (NGS). The RNA quality was very low for all samples, independent of storage time or staining method. The DNA from PPB-stained BM smears was already degraded after 1 year of storage and correspondingly could not be used for reliable downstream molecular analysis. In contrast, DNA extracted from MGG-stained BM smears stored for up to 10 years was able to generate high-quality data in qPCR and targeted NGS analyses. Longer storage periods (>15 years) of these samples revealed a high degree of degradation and a significant amount of DNA transitions and transversions. In conclusion, the DNA extracted from archival MGG-stained BM smears with a storage time up to at least 10 years was qualitatively good and fit for downstream analysis, including targeted NGS. This indicates that these samples are an eligible source for molecular DNA research and for studying complex diseases.

Use of iron ore tailing from tailing dam as catalyst in a fenton-like process for methylene blue oxidation in continuous flow mode.

The global demand for iron ore with high iron contents to supply the steel industry is associated, in most countries, with the generation of tailings from mineral processing. The chemical compositions of iron ore tailings (basically Fe2O3 and SiO2) make them an excellent candidate as a catalyst for advanced oxidation processes (AOPs), especially the Fenton process and its derivatives. Therefore, this paper aimed to transform iron ore tailings from tailing dams into catalysts able to activate H2O2 for the purpose of treating, in a continuous flow, effluents contaminated with organic dyes, employing methylene blue as a model molecule. The mineralogical characteristics of in natura tailings, such as the associations between iron oxides and quartz and the particle sizes of iron oxides, are favourable points for their transformation into catalysts by Fenton-like processes. Different pellet geometries and binding agents were evaluated to optimize the dye removal. Pellet pretreatment in a CH4 atmosphere at 550 °C for 2 h with 10% bentonite as a binding agent (RCSP sample) resulted in the removal of approximately 80% of dye. Kinetic removal data show the good stability of the catalyst in the flow system. Significant catalytic activity loss was not observed after four runs, and data from TG-MS indicate that there is a synergetic mechanism between the adsorption, radical attack and desorption processes of the substrate on the catalyst surface.

Identification of Two Types of Stem Cells in Methylene Blue-stained Sections of Untreated and Diethylstilbestrol-treated Human Prostate Cancer and Their Characterization by Immunogold Localization of CD133.

BACKGROUND: The basal compartment of the prostatic acinus harbors stem and basal cells, whereas the luminal compartment contains cuboidal and columnar cells. Mutation in the genes of stem cells is required for benign (normal) prostate to develop into prostatic adenocarcinoma. Stem/basal cells survive androgen deprivation therapy in humans and castrated mice to repopulate glandular cells by proliferation when stimulated by androgen. We hypothesized that using different embedding and staining methods, it would be possible to identify two types of stem cells in human prostate by localization of CD133. MATERIALS AND METHODS: Prostate biopsy or prostatectomy pieces from 13 untreated and eight diethylstilbestrol-treated men with prostate cancer were sectioned, stained by methylene blue and CD133 was localized by immunogold technique. RESULTS: Methylene blue stained basic proteins in dark basal cells, but not in light cells. Light basal cells expressed androgen receptors and dark cells estrogen receptors. Light and dark cells expressed CD133, indicating them to be stem cells. Light stem cells produced the lineage of columnar/cuboidal cells. Estrogen-dependent dark cells produced a lineage of columnar/cuboidal cells, that also expressed estrogen receptors. CONCLUSION: Our analysis indicates that stem/basal cells are privileged cells in the basal compartment. Stem cells are not under the regulation of steroid hormones, whereas their lineage of cuboidal/columnar cells are. The lineage of androgen-dependent cells are columnar/cuboidal cells and the lineage of estrogen-dependent cells are also columnar/cuboidal cells. Epon-embedding and methylene blue staining showed two types of CD133-positive stem cells in prostate. Paraffin sections did not show two types of stem cells in prostate and bone marrow leukemia cells. Our study indicates the continuity of embryonic stem cells into adult prostate as organ-specific stem cells. To our knowledge, this is the first study to identify two types of stem cells in human prostate.