RESUMO
Nanomaterials such as titanium dioxide and magnetite are increasingly used in several fields, such as water remediation and agriculture. However, this has raised environmental concerns due to potential exposure to organisms like humans. Nanomaterials can cause adverse interactions depending on physicochemical characteristics, like size, morphology, and composition, when interacting with living beings. To ensure safe use and prevent the risk of exposure to nanomaterials, their biocompatibility must be assessed. In vitro cell cultures are beneficial for assessing nanomaterial-cell interactions due to their easy handling. The present study evaluated the biocompatibility of TiO2, Fe3O4, and TiO2/Fe3O4 nanomaterials thermally treated at 350 °C and 450 °C in erythrocytes and HepG2 cells. According to the hemolysis experiments, non-thermally treated NMs are toxic (>5% hemolysis), but their thermally treated counterparts do not present toxicity (<2%). This behavior indicates that the toxicity derives from some precursor (solvent or surfactant) used in the synthesis of the nanomaterials. All the thermally treated nanomaterials did not show hemolytic activity under different conditions, such as low-light exposure or the absence of blood plasma proteins. In contrast, non-thermally treated nanomaterials showed a high hemolytic behavior, which was reduced after the purification (washing and thermal treatment) of nanomaterials, indicating the presence of surfactant residue used during synthesis. An MTS cell viability assay shows that calcined nanomaterials do not reduce cell viability (>11%) during 24 h of exposure. On the other hand, a lactate dehydrogenase leakage assay resulted in a higher variability, indicating that several nanomaterials did not cause an increase in cell death as compared to the control. However, a holotomographic microscopy analysis reveals a high accumulation of nanomaterials in the cell structure at a low concentration (10 µg mL-1), altering cell morphology, which could lead to cell membrane damage and cell viability reduction.
RESUMO
Fungal infections have become a significant public health concern due to their increasing recurrence and harmful effects on plants, animals, and humans. Opportunistic pathogens (among others from the genera Candida and Aspergillus) can be present in indoor air, becoming a risk for people with suppressed immune systems. Engineered nanomaterials are novel alternatives to traditional antifungal therapy. In this work, copper(I) iodide (CuI) and a copper-doped titanium dioxide-copper(I) iodide (TiO2-Cu2+/CuI) composite nanomaterials (NMs)-were synthesized and tested as antifungal agents. The materials were synthesized using sol-gel (TiO2-Cu2+) and co-precipitation (CuI) techniques. The resulting colloids were evaluated as antifungal agents against Candida parapsilosis and Aspergillus niger strains. The NMs were characterized by XRD, HRTEM, AFM, and DLS to evaluate their physicochemical properties. The NMs present a high size dispersion and different geometrical shapes of agglomerates. The antifungal capacity of the NMs by the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) was below 15 µg/mL against Candida parapsilosis and below 600 µg/mL against Aspergillus niger for both NMs. Holotomography microscopy showed that the NMs could penetrate cell membranes causing cell death through its rupture and reactive oxygen species (ROS) production. Cytotoxicity tests showed that NMs could be safe to use at low concentrations. The synthesized nanomaterials could be potential antifungal agents for biomedical or environmental applications.
RESUMO
Finding relations among gene expressions involves the definition of the similarity between experimental data. A simplest similarity measure is the Correlation Coefficient. It is able to identify linear dependences only; moreover, is sensitive to experimental errors. An alternative measure, the Shannon Mutual Information (MI), is free from the above mentioned weaknesses. However, the calculation of MI for continuous variables from the finite number of experimental points, N, involves an ambiguity arising when one divides the range of values of the continuous variable into boxes. Then the distribution of experimental points among the boxes (and, therefore, MI) depends on the box size. An algorithm for the calculation of MI for continuous variables is proposed. We find the optimum box sizes for a given N from the condition of minimum entropy variation with respect to the change of the box sizes. We have applied this technique to the gene expression dataset from Stanford, containing microarray data at 18 time points from yeast Saccharomyces cerevisiae cultures (Spellman et al.,[3]). We calculated MI for all of the pairs of time points. The MI analysis allowed us to identify time patterns related to different biological processes in the cell.
RESUMO
A 2.5-cm nasal septal perforation was performed in 18 pigs and repaired as follows: group I (n = 6), septal perforation without treatment; group II (n = 6), surgical repair with interpositional graft of glutaraldehyde-preserved bovine pericardium (GPBP); group III (n = 6), surgical repair with interpositional graft of lyophilized GPBP (LGPBP). The animals were evaluated clinically and radiologically (x-ray and CT scan) 2 days before surgery, daily during the first postoperative week, and weekly during the next 6 months. At the end of the study the animals were euthanized with an overdose of pentobarbital. Macroscopic and microscopic examination of the grafts and nasal septum was performed. All the animals survived the surgical procedure. Five pigs in group I showed persistence of the septal perforation. All the animals in groups II and III showed total closure of the septal perforation, with the presence of fibrotic tissue on the pericardial grafts as well as in the septal cartilage, and overall good healing. In conclusion, GPBP and LGPBP are adequate materials that can be used as interpositional grafts in the surgical closure of septal perforations in pigs
Assuntos
Septo Nasal/lesões , Septo Nasal/cirurgia , Pericárdio/transplante , Animais , Bovinos , Cauterização/efeitos adversos , Criocirurgia/efeitos adversos , Feminino , Masculino , Complicações Pós-Operatórias/cirurgia , Sus scrofa , Transplante Heterólogo , CicatrizaçãoRESUMO
Con la finalidad de determinar la enfermedad coronaria aterosclerótica en la mujer de ocupación ama de casa. Se realiza un estudio retrospectivo en el servicio Cardiología del Hospital General de las Fuerzas Armadas H.G.1 (Quito-Ecuador) desde feb. 1992 a feb. 1997. En todos los pacientes se analizó factores de riesgo coronario como dislipidemia, hipertensión arterial (HTA), diabetes, obesidad, tabaquismo; de igual manera el cuadro clínico de dolor precordial, los hallazgos observados en el electrocardiograma (ECG) basal. Se realizó prueba de esfuerzo y estudio de cinecoronariografía en todas las pacientes. Fueron analizadas 39 mujeres con edades entre 41 y 72 años (media de 58). No se detectó factores de riesgo en 7 (18xciento), la dislipidemia, la hipertensión y la obesidad fueron los más frecuentes (62, 56 y 21xciento respectivamente). El dolor precordial típico estuvo presente en 26 (67xciento) y atípico en 13 pacientes (33xciento). En el ECG se observó cambios de la repolarización ventricular en 34 (87xciento) con p0.05. Se realizó Ergometria en 35 pacientes siendo francamente positivas para isquemia miocárdica en 30 (77xciento) y dudosas en 5 (14xciento). Eco-Dipiridamol (+) en 3 pacientes (8xciento) y en una paciente demostró isquemia silente en estudio Holter. De los 35 pacientes que se realizaron Prueba de esfuerzo en banda sinfín con escala de Bruce, 31 pacientes (89xciento) estuvieron en Clase funcional (II) llegaron a la 3era etapa 28 (80xciento). Y al observar la alteración del segmento ST en el ECG de esfuerzo fue la zona infero-lateral la que predominó en 32 pacientes (91.4xciento) con p0.02. La coronariografía no demostró lesiones ateroscleróticas en 32 (82xciento) con una probabilidad estadística de (91xciento), encontrándose lesión ateroscleróticas en 7 (18xciento), siendo significativa con estrechez coronaria + del 70xciento en un paciente (2.5xciento); lesiones de 3 vasos coronarios en 2 (5.1xciento) y lesiones de un vaso en 5 (13xciento). Puente miocárdico en 5 (13xciento) e Hipertrofia ventricular izquierdo en 20 (51xciento)...