Enhanced susceptibility to apoptosis and growth arrest of human breast carcinoma cells treated with silica nanoparticles loaded with monohydroxy flavone compounds.

The treatment of drug-resistant cancer is a clinical challenge, hence screening for novel anticancer drugs is critically important. In this study, we investigated the anti-tumor potential of three plant-derived flavone compounds: 3-hydroxy flavone (3-HF), 6-hydroxy flavone (6-HF), and 7-hydroxy flavone (7-HF), either alone or combined with silica nanoparticles (3-HF + NP, 6-HF + NP, and 7-HF + NP), on the human breast carcinoma cell lines MDA-MB-231 and MCF-7, as well as on non-tumorigenic normal breast epithelial cells (MCF-10). The IC50 values of these flavone compounds loaded with NP (flavones + NP) in these cell lines were determined to be 1.5 µg/mL without affecting the viability of normal MCF-10 cells. Additionally, using annexin V - propidium iodide double-staining followed by flow cytometry analysis, we found that the combination of flavones with NP significantly induced apoptosis in MCF-7 and MDA-MB-231 cancer cells. Furthermore, flavones + NP increased the expression of cytochrome c and caspase-9, mediating the growth arrest of these cancer cells. Most importantly, the combination of flavones with NP significantly abolished the expression of ATF-3, which is responsible for the proliferation and invasion of bone-metastatic breast cancer cells. Our data revealed the potential therapeutic effects of these flavones in fighting breast cancer cells, and provide the first insights concerning the underlying molecular mechanisms.

Effects of silica nanoparticles on endolysosome function in primary cultured neurons 1.

Silica nanoparticles (SiNPs) have been used as vehicles for drug delivery, molecular detection, and cellular manipulations in nanoneuromedicine. SiNPs may cause adverse effects in the brain including neurotoxicity, neuroinflammation, neurodegeneration, and enhancing levels of amyloid beta (Aß) protein-all pathological hallmarks of Alzheimer's disease. Therefore, the extent to which SiNPs influence Aß generation and the underlying mechanisms by which this occurs deserve investigation. Our studies were focused on the effects of SiNPs on endolysosomes which uptake, traffic, and mediate the actions of SiNPs. These organelles are also where amyloidogenesis largely originates. We found that SiNPs, in primary cultured hippocampal neurons, accumulated in endolysosomes and caused a rapid and persistent deacidification of endolysosomes. SiNPs significantly reduced endolysosome calcium stores as indicated by a significant reduction in the ability of the lysosomotropic agent glycyl-l-phenylalanine 2-naphthylamide (GPN) to release calcium from endolysosomes. SiNPs increased Aß1-40 secretion, whereas 2 agents that acidified endolysosomes, ML-SA1 and CGS21680, blocked SiNP-induced deacidification and increased generation of Aß1-40. Our findings suggest that SiNP-induced deacidification of and calcium release from endolysosomes might be mechanistically linked to increased amyloidogenesis. The use of SiNPs might not be the best nanomaterial for therapeutic strategies against Alzheimer's disease and other neurological disorders linked to endolysosome dysfunction.

Evaluation of the therapeutic effects of rice husk nanosilica combined with platelet-derived growth factor in hepatic veno-occlusive disease.

Veno-occlusive disease is an important pattern of hepatotoxicity associated with antineoplastic drugs. The study investigated the possible therapeutic effects of RHS nanoparticles combined with a PDGF on veno-occlusive disease (VOD) in liver elicited in rats with DAC. In this work, nanosilica (SiO2) was successfully prepared from rice husk, and its physicochemical characteristics were investigated using EDX, XRD, N2 adsorption-desorption isotherm, SEM, and TEM. Forty-eight male Sprague-Dawely rats were distributed into 6 groups, with 8 rats in each. The first group served as the control. In the second group, animals were infused with DAC (0.015 mg/kg; 1-3 days) by intraperitoneal injection (i.p.). In the third group, rats were injected i.p. with DAC, and then at 24 h following the last dose of DAC, received nano-RHS incorporated with PDGF twice a week for 4 weeks. In the fourth group, normal animals were injected with RHS. In the fifth group, normal rats received PDGF, and in the sixth group, normal rats received nano-RHS combined with PDGF. The prepared nanosilica showed type II adsorption isotherm characteristic for mesoporous materials with a specific surface area of 236 m2/g. TEM imaging confirmed the production of nanoparticles via the followed preparation procedure. Radical scavenging potential for nano-RHS was determined using two different in-vitro assays: DPPH, and ABTS radicals. The results of this work show that administration of nano-RHS combined with PDGF significantly reversed the oxidative stress effects of DAC as evidenced by a decrease in liver function. It can be concluded that the nano-RHS combined with PDGF is useful in preventing oxidative stress and hepatic VOD induced by chemotherapy such as DAC.

Systemic sclerosis, silica exposure and cellular therapies: The sand in the gears?

Systemic sclerosis (SSc) is a chronic orphan autoimmune disease with the highest mortality rate among rheumatic diseases. SSc-related interstitial-lung disease (ILD) remains among the leading causes of SSc-related mortality with still few therapeutic effective strategies. In patients with crystallin silica exposure, SSc is recognized as an occupational disease according to the French social security system (Table 25A of the general insurance regimen). Lympho-ablative or myeloablative immunosuppression followed by autologous hematopoietic stem-cell transplantation (aHSCT) is the only therapeutic approach with demonstrated efficacy, improved survival with disease modifying effects on SSc-fibrotic manifestations (skin disease and ILD) and quality of life. A documented past and/or present occupational silica exposure, with extensive exposure and/or silica-related ILD and/or with persistent silica content in the broncho-alveolar lavage fluid are contra-indications to aHSCT in SSc patients, due to the risk of silica-related malignancy or of SSc relapse. This article aims to discuss alternative options in SSc patients with a history of silica exposure, and how innovative cellular therapies (mesenchymal stromal cells, CAR cells) could represent new therapeutic options for these patients.

Foreign body granulomatous reaction to silica, silicone, and hyaluronic acid in a patient with interferon-induced sarcoidosis.

We report the case of a patient who developed sarcoid granulomas 11 months after starting treatment with pegylated interferon alfa and ribavirin for chronic hepatitis C. The sites of the lesions were related to 3 different foreign bodies: silica in old scars on the skin, hyaluronic acid that had been injected into facial tissues, and silicone in an axillary lymph node draining the area of a breast implant. Systemic sarcoidosis was diagnosed on the basis of a history of dry cough and fever and blood tests that revealed elevated angiotensin converting enzyme and liver enzymes. Interruption of the antiviral therapy led to normalization of liver function tests and disappearance of the skin lesions and lymphadenopathies. Dermatologists and cosmetic surgeons should be aware of the risk of sarcoid lesions related to cosmetic implants in patients who may require treatment with interferon in the future.

[Silica causes difficulties]. / La silice cause des difficultés.

Silicosis and sarcoidosis are two very distinct entities in the literature. All the additional non-invasive examinations, including the chest CT scan, often do not differentiate them. The history, including occupational exposure to identified silica particles, is a discriminating factor. However, due to the pathogenic power of silica, it would be possible to have the simultaneous development of these two pathologies in the same patient. To illustrate this situation, here is the case of a 62-year-old patient, who presented initially with a picture of dyspnea and productive cough. The chest CT showed micronodular peribronchovascular infiltrates and mediastinal lymphadenopathy. The other additional examinations did not find anything specific. In the diagnostic process, the patient had multiple endoscopic samples which did not make it possible to be conclusive on one or the other of these pathologies. He therefore underwent a surgical lung biopsy which revealed histological lesions compatible with the two pathologies. Recent studies suggest that inhaled particles, especially silica, could be responsible for the pattern of sarcoidosis. However, it is difficult to say whether, in this case, silica was responsible for the development of sarcoidosis.

Biosynthesis of a Novel Antibacterial Dipeptide, Using Proteases From South American Native Fruits, Useful as a Food Preservative.

Antiacanthain and granulosain are the partially purified proteolytic extracts from the South American native fruits of Bromelia antiacantha (Bertol. ) and Solanum granuloso leprosum, respectively. The aim of this work was to compare the ability of both soluble and immobilized antiacanthain and granulosain f or the synthesis of Z-Tyr-Val-OH, a novel antibacterial dipeptide, in different reaction systems formed by almost anhydrous organic solvents (Xw: 1 × 10-5) and several percentages of immiscible organic solvents in 100 mM Tris(hydroxymethyl)aminomethane hydrochloride buffer pH 8.0. Soluble antiacanthain in half of the 24 different organic biphasic media showed higher catalytic potential than in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0. Soluble granulosain showed lower catalytic potential in all liquid-liquid biphasic media than in the same buffer. However, 50% (v/v) ethyl ethanoate in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0 allowed to express the highest catalytic potential of both soluble enzymes. In 50% v/v ethyl ethanoate, soluble antiacanthain and granulosain catalyzed the synthesis of Z-Tyr-Val-OH with 72 ± 0.15 and 60 ± 0.10% maximal peptide yields, respectively. Multi-point immobilization in glyoxyl-silica did not lead to better peptide yields than soluble enzymes, in that liquid-liquid biphasic medium under the same reaction conditions. Soluble and glyoxyl-silica immobilized antiacanthain in almost anhydrous ethyl ethanoate (Xw: 1 × 10-5) were able to retain 17.3 and 45% of the initial proteolytic activity of antiacanthain in 100 mM Tris hydrolchloride buffer pH 8.0, respectively, at 40°C under agitation (200 rpm). Soluble and glyoxyl-silica immobilized granulosain were inactivated under the same reaction conditions. Glyoxyl-silica immobilized antiacanthain showed to be a robust biocatalyst in almost anhydrous ethyl ethanoate (Xw: 1 × 10-5), eliciting the best peptide yield (75 ± 0.13%). The synthesis reaction of Z-Tyr-Val-OH could not proceed when soluble antiacanthain was used under the same conditions. Both peptidases only catalyzed the synthesis reaction under kinetic control, using activated acyl donor substrates. Finally, this work reports a novel broad-spectrum antibacterial peptide that significantly decreased (p ≤ 0.05) the specific growth rates of Gram positive and Gram negative microorganisms at very low concentrations (≥15 and 35 µg/ml, respectively); contributing with a new safe food preservative of applying for different food systems.

Silicosis: A former occupational disease with new occupational exposure scenarios. / Silicosis: una antigua enfermedad profesional con nuevos escenarios de exposición laboral.

BACKGROUND: Recent studies have shown an increase in the prevalence of silicosis due to the use of artificial quartz aggregates (AQA). The aim of this study was to assess the cases of silicosis in our area reported to the Healthcare Information System for Occupational Epidemiological Surveillance of the Autonomous Community of Valencia to detect new agents of exposure to silica and working conditions that promote its onset. MATERIAL AND METHOD: A descriptive study was conducted of cases of silicosis reported to the Healthcare Information System for Occupational Epidemiological Surveillance of the Autonomous Community of Valencia from January 2009 to September 2016. The data sources include epidemiological-occupational surveys and medical reports. RESULTS: Nineteen cases of silicosis were reported, 74% of which were diagnosed using high-resolution computed tomography. Some 68.4% of the cases were related to the handling of AQA, as assemblers/cutters/sanders of countertops. The subgroup's mean age was 46.62±13.33 years, and the mean exposure was 11.00±3.58 years. The rest of the patients worked in companies with no AQA exposure, with a mean age of 62.33±16.22 years and a mean exposure of 27.16±8.44 years (P<.05). Four cases presented complicated forms (3 exposed to AQA). CONCLUSIONS: The work of assembling/cutting/sanding AQA countertops presents a high risk of developing the disease. The mean age at onset and the exposure time for this group is lower, and the percentage of complicated clinical forms is higher. Improvements need to be made in preventive planning for companies with exposure to these new agents.

[Screening of occupational exposure to asbestos and silica by job-exposure matrix among patients with lung cancer and mesothelioma]. / Dépistage des expositions professionnelles à l'amiante et à la silice par matrice emplois-expositions auprès de patients atteints de cancer bronchopulmonaire et de mésothéliome.

INTRODUCTION: In the context of underreporting of occupational diseases, the aim was to study the validity of silica and asbestos job-exposure matrices in screening occupational exposure in the field of thoracic oncology. METHODS: Fifty patients hospitalized with primitive lung cancer or mesothelioma in a university hospital center in the Hauts-de-Seine department of France were included between November 2016 and September 2017. For each patient 1/the job history was collected, from which data was entered single-blindly into the job-exposure matrices by a resident in occupational medicine, 2/a questionnaire (Q-SPLF) was completed similarly, and 3/the patients also had a consultation with a chief resident in occupational medicine, considered the gold standard. The main outcome was the diagnostic performance of the matrices. The Q-SPLF diagnostic performance was also studied. RESULTS: The asbestos and silica matrices had sensitivities of 100%, specificities of respectively 76.1% and 87.8%, the positive likelihood ratios were at 4.19 [2.5-6] and 8.17 [3.8-10], and the negative likelihood ratios were at 0. The Q-SPLF diagnostic performance was comparable to that of the matrices. CONCLUSIONS: The matrices and the questionnaire have a great diagnostic performance which seems interesting for a use as a screening tool for occupational exposures. These results have yet to be confirmed by large-scale studies.

Skin Biopsy in the Context of Systemic Disease. / La biopsia cutánea en el contexto de la enfermedad sistémica.

The skin is the largest and most exposed organ in the human body and the ideal place to look for signs that aid in the early diagnosis of systemic diseases with cutaneous effects. As the concepts that underpin our understanding of many of these diseases have evolved or expanded in recent years, there have also been changes in the criteria we use for early diagnosis, including our approaches to skin biopsy and dermatopathologic evaluation. This review focuses on some of the systemic processes with skin manifestations for which our basic understanding has changed most in recent decades.

Evaluation of the exposure to coal dust and prevalence of pneumoconiosis in underground mining in three Colombian departments / Evaluación de la exposición al polvo de carbón y de sílice en sitios de minería subterránea en tres departamentos de Colombia

Introduction: Coal workers' pneumoconiosis is a chronic and irreversible disease representing a public health problem. Objective: To estimate the prevalence of pneumoconiosis and its associated factors among underground coal miners in the Colombian departments of Boyacá, Cundinamarca and Norte de Santander. Materials and methods: We conducted a cross-sectional study of 476 miners to measure the prevalence of pneumoconiosis and its associated factors such as coal dust and silica levels, as well as the occupational conditions. The medical assessment and a chest x-ray were performed according to the International Labor Organization criteria, along with spirometry and the identification of glutathione S-transferase and repair enzyme polymorphisms.The associations were explored using Cox regression models. Results: We performed a total of 479 environmental monitoring sessions in 31 companies and we evaluated 476 workers with 10 to 57 years of mining work experience. The prevalence of pneumoconiosis was 33.8% (95% CI: 27.0 - 41.3%). In the Cox multivariate regression model with a constant risk time, pneumoconiosis was significantly associated with working in medium-sized companies (PR=2.00, 95% CI: 0.995 - 2.690; p=0.052), the level of severe exposure to coal dust (PR=2.055, 95% CI: 1.043 - 4.048; p=0.038), and working in underground mining for 25 years or more (for those with 25.0-29.9 years: PR=2.199, 95% CI: 1.449 - 3.338; p=0.001). Conclusions: The prevalence of pneumoconiosis was very high and was found to be associated with severe exposure to coal dust, work exposure for 25 years or more and working in medium-sized enterprises

Introducción. La neumoconiosis de mineros del carbón es una enfermedad crónica e irreversible que se considera un problema de salud pública. Objetivo. Estimar la prevalencia de neumoconiosis y sus factores asociados en mineros de carbón de Boyacá, Cundinamarca y Norte de Santander. Materiales y métodos. Se hizo un estudio de corte transversal en 476 mineros. Se les hizo valoración médica, se tomaron radiografías de tórax siguiendo los criterios de la Organización Internacional del Trabajo, así como espirometrías, y se identificaron los polimorfismos de la glutatión S-transferasa y de las enzimas de reparación. Las asociaciones entre las condiciones ocupacionales y de la empresa con la neumoconiosis, se estudiaron usando modelos de regresión de Cox. Resultados. En 31 empresas se hicieron 479 monitorizaciones ambientales y se evaluaron 476 trabajadores cuyo tiempo de trabajo fluctuaba entre 10 y 57 años. La prevalencia de la neumoconiosis fue de 33,8 % (IC95% 27,0-41,3). En el modelo de regresión multivariado de Cox, con tiempo de riesgo constante para la neumoconiosis, esta se asoció significativamente con el trabajo en empresas medianas (razón de prevalencias, RP=2,00; IC95% 0,995- 2,690; p=0,052), con un nivel alto de exposición al polvo de carbón según el índice de exposición (RP=2,055; IC95% 1,043-4,048; p=0,038), y una antigüedad de 25 años o más (para 25,0 a 29,9 años: RP=2,199; IC95% 1,449-3,338; p=0,001). Conclusiones. La prevalencia de la neumoconiosis fue muy alta y se asoció a la exposición a altos niveles de polvo de carbón, a una exposición laboral mayor o igual a 25 años y al trabajo en empresas medianas.

Silicosis en el Paraguay: la amenaza no se ha ido

La literatura médica nacional guarda una asignatura pendiente relativa a las enfermedades ocupacionales. La silicosis es la neumoconiosis más frecuente y se debe a la inhalación de sílice cristalina y, acorde a la susceptibilidad individual junto a la intensidad de exposición y a la concentración del mineral en el aire, puede originar determinadas formas clínicas. La silicosis crónica es la forma más frecuente y se asocia a varios tipos de labores como cavar pozos y el trabajo en canteras. En los últimos tiempos se relatan otros oficios que pueden originar formas más aceleradas de la enfermedad en tiempos más abreviados de exposición, recrudeciendo brotes preocupantes en adultos en edad laboral. Realizamos una revisión narrativa de trabajos observacionales hechos en el Paraguay con el objetivo de analizar varios aspectos puntualizando las aristas clínicas y demográficas regionales.

Occupational diseases remain an unresolved issue in the national medical literature. The most common form of pneumoconiosis is silicosis, which is brought on by inhaling crystalline silica and depending on the susceptibility of the person, the extent of their exposure, and the concentration of the mineral in the air, silicosis can result in different clinical forms. The most prevalent type, chronic silicosis, is linked to a variety of jobs, including well digging and quarry work. In recent times, other trades have been reported that can cause more accelerated forms of the disease in shorter exposure times, worsening worrying outbreaks in working-age adults. With the intention of assessing various elements and highlighting certain clinical and regional demographic aspects, we performed a narrative review of observational studies conducted in Paraguay.

Silicoproteinosis en paciente minero en Colombia. Reporte de caso / Silicoproteinosis in a mining patient in Colombia. Case report

La silicosis pulmonar es una enfermedad ocupacional que continúa ocasionando morbilidad en el mundo. Debido a que el sílice es el mineral más abundante en la tierra y en las rocas, son numerosas las fuentes de exposición laboral a la inhalación del polvo de sílice en varios sectores industriales. Por su parte, la silicoproteinosis pulmonar es una forma aguda muy rara de silicosis, que puede desarrollarse con un período de latencia más corto en comparación con la silicosis, luego de la primera exposición al sílice, y se caracteriza por un rápido deterioro de la función pulmonar, sin respuesta efectiva a ningún tratamiento. Por su forma de presentación tan atípica, reportamos el caso de un hombre de 58 años, con antecedente laboral de trabajo en mina de extracción de oro en socavón

Pulmonary silicosis is an occupational disease that continues to cause morbidity in the world. Because silica is the most abundant mineral in soil and rock, sources of occupational exposure to inhalation of silica dust are numerous in various industrial sectors. Alternately, pulmonary silicoproteinosis is a very rare acute form of silicosis, which can develop with a shorter latency period compared to silicosis after the first exposure to silica, and is characterized by a rapid deterioration of lung function, without effective response to any treatment. Due to its atypical form of presentation, we report the case of a 58-year-old man, with a history of working in a gold mine

[Silicotuberculosis]. / La silicotuberculose.

OBJECTIVE: Tuberculosis is a serious and common complication of silicosis. The aim of this study is to describe the epidemiological, clinical, radiological and progressive aspects of this pathological entity. PATIENTS AND METHODS: The study concerns 23 cases of silicotuberculosis which were collected at the service of respiratory diseases at CHU Ibn Rochd of Casablanca, Morocco during 12years (2003-2015). RESULTS: All patients were men. They were 7 diggers, 5 rock crushers, 7 miners and 4 masons. The mean duration of silica exposure was 11years. The symptomatology was dominated by dyspnea and persistent bronchial syndrome. Imagery showed tumor-like opacities in all cases, associated with mediastinal calcified lymphadenopathy in 9 cases, with micronodules in 8 cases and an excavated opacity in 2 cases. The diagnosis of tuberculosis was confirmed by isolation of the Koch's bacillus in sputum in 13% of cases in the bronchial aspirate in 52% and culture in sputum post-bronchoscopy in 13%. The bronchial biopsies confirmed the diagnosis in 2 cases. Tuberculosis had complicated silicosis 9years on average after the cessation of exposure to silica in 65% of cases. The antituberculous treatment was started in all patients with good clinical outcome in 22 cases. We had deplored a case of death by acute respiratory failure. CONCLUSION: Silicosis increases the risk of tuberculosis, hence the importance of TB screening in all patients with silicosis.

[Systemic sclerosis and occupational exposures: About a case in a driller-powderman]. / Sclérodermie systémique et expositions professionnelles: à propos d'un cas chez un foreur-artificier.

INTRODUCTION: Erasmus' syndrome is the association between systemic sclerosis and silica exposure. CASE REPORT: We report a case of this syndrome in a driller-powderman exposed to silica and nitro compounds contained in explosives. CONCLUSION: Physiopathology and etiologies of systemic sclerosis are still not well known. However, nitric oxide, a product of nitro compounds metabolism, is involved in the physiopathology of the disease: it seems thus licit to wonder about the consequences of an uncontrolled occupational exposure to nitric oxide on the vascular function, already damaged by systemic sclerosis. To a wider extent, our report highlights the importance of a comprehensive and detailed collection of occupational exposures for patients diagnosed with systemic sclerosis.

Marcaje de arena sílice con 99mTc para la obtención de un radiotrazador sólido / Labeling of silica sand with 99mTc for obtaining a solid radiotracer

Resumen Para la obtención de radiotrazadores sólidos de 99mTc actualmente se necesitan nuevos soportes porosos. Estudios anteriores realizados por otros autores mostraron la posibilidad del marcaje con 99mTc de sedimentos de ríos con alto contenido de aluminosilicatos. En el presente trabajo se desarrolló una metodología para el marcaje de arena sílice con el 99mTcO4- para su uso como radiotrazador sólido. Se realizó el marcaje de la arena sílice previamente tratada y sin tratar empleando concentraciones variables de cloruro y fluoruro estañoso como agentes reductores y diferentes tiempos de marcaje. Se evaluó la influencia de la etapa de tratamiento previo de la arena en los rendimientos de retención del Tc obtenidos. Los cambios en la composición de la arena sílice luego de su tratamiento previo se pudieron constatar a partir de la Microscopía Electrónica de Barrido (SEM-EDS). Los resultados sugirieren el empleo de la arena sílice previamente tratada y de fluoruro estañoso como agente reductor, adicionalmente se propusieron modificaciones a la metodología inicial de tratamiento previo de la arena. Se pudo constatar a partir de la técnica SEM-EDS que el aumento del porciento de retención del Tc en la arena luego de su tratamiento, se debe fundamentalmente a los cambios observados en su composición química y en su estructura. Se logró la obtención de un radiotrazador sólido marcado con 99mTc en soporte de arena sílice con un tiempo de preparación estimado de 4 horas y un rendimiento de retención de 74%.

Abstract To obtain 99mTc solid radiotracers, new porous supports are currently needed. Previous studies carried out by other authors showed the possibility of 99mTc labeling of sediments from rivers with a high content of aluminosilicates. In the present work a methodology for labeling of silica sand with 99mTcO4- as a prospective solid radiotracer was developed. Labeling of the previously treated and untreated silica sand was carried out using variable concentrations of chloride and stannous fluoride as reducing agents and different labeling times. The influence of the pre-treatment stage of the sand on the obtained Tc retention yields was evaluated. The changes in the composition of the silica sand after its previous treatment could be verified from the Scanning Electron Microscopy (SEM-EDS). The results suggested the use of previously treated silica sand and stannous fluoride as a reducing agent, modifications were proposed to the initial methodology of previous treatment of the sand. It was possible to confirm from the SEM-EDS technique that the increase in the percentage of retention of Tc in the sand after its treatment is mainly due to the observed changes in its chemical composition and structure. It was possible to obtain a 99mTc solid radiotracer on support of silica sand with an estimated preparation time of 4 hours and a retention yield of 74%.

Validation of stationary phases in (111)In-pentetreotide planar chromatography.

INTRODUCTION: Since Pall-German stopped manufacturing ITLC-SG, it has become necessary to validate alternative stationary phases. OBJECTIVE: To validate different stationary phases versus ITLC-SG Pall-Gelman in the determination of the radiochemical purity (RCP) of (111)In-pentetreotide ((111)In-Octreoscan) by planar chromatography. MATERIAL AND METHODS: We conducted a case-control study, which included 66 (111)In-pentetreotide preparations. We determined the RCP by planar chromatography, using a freshly prepared solution of 0,1M sodium citrate (pH 5) and the following stationary phases: ITLC-SG (Pall-Gelman) (reference method), iTLC-SG (Varian), HPTLC silica gel 60 (Merck), Whatman 1, Whatman 3MM and Whatman 17. For each of the methods, we calculated: PRQ, relative front values (RF) of the radiopharmaceutical and free (111)In, chromatographic development time, resolution between peaks. We compared the results obtained with the reference method. The statistical analysis was performed using the SPSS program. The p value was calculated for the study of statistical significance. RESULTS: The highest resolution is obtained with HPTLC silica gel 60 (Merck). However, the chromatographic development time is too long (mean=33.62minutes). Greater resolution is obtained with iTLC-SG (Varian) than with the reference method, with lower chromatographic development time (mean=3.61minutes). Very low resolutions are obtained with Whatman paper, essentially with Whatman 1 and 3MM. Therefore, we do not recommend their use. CONCLUSIONS: Although iTLC-SG (Varian) and HPTLC silica gel 60 (Merck) are suitable alternatives to ITLC-SG (Pall-Gelman) in determining the RCP of (111)In-pentetreotide, iTLC-SG (Varian) is the method of choice due to its lower chromatographic development time.

Percepción de riesgo de exposición ocupacional a sílice: construcción y validación de un cuestionario en Chile / Risk perception of occupational exposure to silica: construction and validation of a questionnaire in Chile

Resumen: Introducción: La silicosis es una enfermedad pulmonar progresiva, irreversible, pero potencialmente prevenible. Conocer la percepción de riesgo en trabajadores expuestos a sílice es necesario para intervenir y reducir la incidencia de silicosis y otras enfermedades relacionadas. El objetivo de este estudio fue validar un Cuestionario de Percepción de Riesgo de Exposición Ocupacional a Sílice (CuPREOS) en trabajadores expuestos, en distintas actividades laborales en Temuco, Chile. Material y método: Una etapa de exploración con enfoque fenomenológico/ naturalista permitió conformar categorías de primer y segundo orden, que concluyó en una primera versión del instrumento. Una segunda etapa incluyó análisis factorial exploratorio y confirmatorio. Resultados: Se develaron dos dimensiones subyacentes: a) evidencia de riesgo, en la que el trabajador manifiesta evaluar señales de alarma y b) ausencia de riesgo, en la que sopesa aspectos que contrarrestan las anteriores. Ambas configuran la estructura conceptual que conforma el CuPREOS de 9 ítems/preguntas, con una confiabilidad de 0.84 (alfa Cronbach). Los indicadores del análisis confirmatorio revelan un buen ajuste del mode lo. Discusión: la percepción de riesgo es un constructo que involucra complejidades sociales y culturales, su medición debe ser sencilla y práctica; su conocimiento permitiría decisiones más efectivas en pre vención e intervención.

Abstract: Introduction: Silicosis is a progressive lung disease, irreversible, but potentially preventable. Knowing the perception of risk in workers exposed to silica is necessary to intervene and reduce the incidence of silicosis and other related diseases. The objective of this study was to validate a Questionnaire of risk perception of occupational expo sure to silica (CuPREOS) in exposed workers, in different work activities in Temuco, Chile. Material and method: A stage of explo ration with phenomenological/naturalist approach allowed to create categories of first and second order, which ended in a first version of the instrument. The second stage included exploratory and con firmatory factor analysis. Results: two underlying dimensions were revealed: a) evidence of risk, in which worker states to evaluate signals of alarm and b) absence of risk, in which he weighs aspects that counteract the previous ones. Both set up the conceptual frame work that sustain the CuPREOS of 9 items/questions, with a reliabil ity of 0.84 (Cronbach alfa). The confirmatory analysis indicators show a good fit of the model. Discussion: the perception of risk is a construct involving social and cultural complexities, its measurement should be simple and practical; its knowledge would enable more effective decision-making in prevention and intervention.

Evaluación de la exposición al polvo de carbón y de sílice en sitios de minería subterránea en tres departamentos de Colombia / Evaluation of the exposure to coal dust and prevalence of pneumoconiosis in underground mining in three Colombian departments

Introducción. La neumoconiosis de mineros del carbón es una enfermedad crónica e irreversible que se considera un problema de salud pública. Objetivo. Estimar la prevalencia de neumoconiosis y sus factores asociados en mineros de carbón de Boyacá, Cundinamarca y Norte de Santander. Materiales y métodos. Se hizo un estudio de corte transversal en 476 mineros. Se les hizo valoración médica, se tomaron radiografías de tórax siguiendo los criterios de la Organización Internacional del Trabajo, así como espirometrías, y se identificaron los polimorfismos de la glutatión S-transferasa y de las enzimas de reparación. Las asociaciones entre las condiciones ocupacionales y de la empresa con la neumoconiosis, se estudiaron usando modelos de regresión de Cox. Resultados. En 31 empresas se hicieron 479 monitorizaciones ambientales y se evaluaron 476 trabajadores cuyo tiempo de trabajo fluctuaba entre 10 y 57 años. La prevalencia de la neumoconiosis fue de 33,8 % (IC95% 27,0-41,3). En el modelo de regresión multivariado de Cox, con tiempo de riesgo constante para la neumoconiosis, esta se asoció significativamente con el trabajo en empresas medianas (razón de prevalencias, RP=2,00; IC95% 0,995- 2,690; p=0,052), con un nivel alto de exposición al polvo de carbón según el índice de exposición (RP=2,055; IC95% 1,043-4,048; p=0,038), y una antigüedad de 25 años o más (para 25,0 a 29,9 años: RP=2,199; IC95% 1,449-3,338; p=0,001). Conclusiones. La prevalencia de la neumoconiosis fue muy alta y se asoció a la exposición a altos niveles de polvo de carbón, a una exposición laboral mayor o igual a 25 años y al trabajo en empresas medianas.

Introduction: Coal workers' pneumoconiosis is a chronic and irreversible disease representing a public health problem. Objective: To estimate the prevalence of pneumoconiosis and its associated factors among underground coal miners in the Colombian departments of Boyacá, Cundinamarca and Norte de Santander. Materials and methods: We conducted a cross-sectional study of 476 miners to measure the prevalence of pneumoconiosis and its associated factors such as coal dust and silica levels, as well as the occupational conditions. The medical assessment and a chest x-ray were performed according to the International Labor Organization criteria, along with spirometry and the identification of glutathione S-transferase and repair enzyme polymorphisms. The associations were explored using Cox regression models. Results: We performed a total of 479 environmental monitoring sessions in 31 companies and we evaluated 476 workers with 10 to 57 years of mining work experience. The prevalence of pneumoconiosis was 33.8% (95% CI: 27.0 - 41.3%). In the Cox multivariate regression model with a constant risk time, pneumoconiosis was significantly associated with working in medium-sized companies (PR=2.00, 95% CI: 0.995 - 2.690; p=0.052), the level of severe exposure to coal dust (PR=2.055, 95% CI: 1.043 - 4.048; p=0.038), and working in underground mining for 25 years or more (for those with 25.0-29.9 years: PR=2.199, 95% CI: 1.449 - 3.338; p=0.001). Conclusions: The prevalence of pneumoconiosis was very high and was found to be associated with severe exposure to coal dust, work exposure for 25 years or more and working in medium-sized enterprises.