MCF-7 cells as a three-dimensional model for the study of human breast cancer

The increasing use of three-dimensional (3D) cell culture is because it reproduces in vitro results similar to in vivo results. Multicellular tumor spheroids generated in vitro exhibit important characteristics of avascular tumors, mainly with respect to tumor physiology and microenvironment. The interaction among cells in a tridimensional culture environment enhances cell differentiation and leads to luminal formation in some breast-derived cell cultures. The present work describes a method that permits luminal formation in breast adenocarcinoma cell (MCF-7)-derived spheroids in a 3D environment. In the proposed model, several relevant parameters, such as cell survival, apoptosis, autophagy, and E-cadherin expression, were analyzed to understand the organization of MCF-7 cells during different culture phases, including luminal and bud formation.     

Effect of etching time and light source on the bond strength of metallic brackets to ceramic

This study evaluated the bond strength of brackets to ceramic testing different etching times and light sources for photo-activation of the bonding agent. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 20 or 60 s. After application of silane on the ceramic surface, metallic brackets were bonded to the cylinders using Transbond XT (3M Unitek). The specimens for each etching time were assigned to 4 groups (n=15), according to the light source: XL2500 halogen light, UltraLume 5 LED, AccuCure 3000 argon laser, and Apollo 95E plasma arc. Light-activation was carried out with total exposure times of 40, 40, 20 and 12 s, respectively. Shear strength testing was carried out after 24 h. The adhesive remnant index (ARI) was evaluated under magnification. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Specimens etched for 20 s presented significantly lower bond strength (p<0.05) compared with those etched for 60 s. No significant differences (p>0.05) were detected among the light sources. The ARI showed a predominance of scores 0 in all groups, with an increase in scores 1, 2 and 3 for the 60 s time. In conclusion, only the etching time had significant influence on the bond strength of brackets to ceramic.     

Effect of a quality improvement intervention to decrease delays in antibiotic delivery in pediatric febrile neutropenia: A pilot study

Purpose

Guidelines recommend the early (less than 1 hour) initiation of antibiotics for patients with severe sepsis. We hypothesize that a simple quality improvement intervention, leaving the first dose of broad-spectrum antibiotics available in the emergency cart, decreases the time to delivery of antibiotics and reduces medical complications in pediatric oncologic patients with febrile neutropenia.

Materials and Methods

Before and after observation of time to antibiotic delivery. The study population included patients (age ≤18 years) undergoing chemotherapy who were admitted in a pediatric intensive care unit with fever related to an infection as a major diagnostic category. Twenty-five patient charts were reviewed for each period. Data were retrospectively collected with a standardized form.

Results

Time to antibiotic delivery was significantly reduced in the post-intervention period, from a median 164 minutes (interquartile range, 108-172 minutes) to a median 55 minutes (interquartile range, 18-225 minutes). The proportion of patients receiving antibiotics in less than 60 minutes increased from 0% (95% confidence interval, 0%-14%) in the preintervention period to 52% (95% confidence interval, 30%-74%; P < .001) in the post-intervention period. Complication rates were low during both periods.

Conclusion

Our results suggest that simple interventions can reduce time to antibiotic administration in a selected group of patients in a pediatric intensive care unit.     

The antioxidant properties of different phthalocyanines

Oxidative stress is involved in the etiology of several chronic diseases, including cardiovascular disease, diabetes, cancer, and neurodegenerative disorders. From this perspective, we have evaluated the possible antioxidant capacities of five different phthalocyanines (PCs), consisting of four metallophthalocyanines (MPCs) and one simple phthalocyanine (PC) in order to explore, for the first time, the potential antioxidant activities of these compounds. Our results show that all PCs tested in this study have significant antioxidant activity in lipid peroxidation assay, providing protection from sodium nitroprusside -induced oxidative damage to supernatant from the homogenized liver, brain, e rim of mice. Compared to the non-induced control, the PCs were generally more efficient in reducing malondialdehyde levels in all assays on lipid peroxidation induced by sodium nitroprusside; the order of approximate decrease in efficiency was as follows: manganese-PC (better efficiency)>copper-PC>iron-PC>zinc-PC>PC (worst efficiency). Furthermore, the copper-PC and manganese-PC compounds exerted a significant protective effect in deoxyribose degradation assays, when employing Fe(2+), Fe(2+)+H(2)O(2), and H(2)O(2) solutions. In conclusion, all PCs tested here were shown to be promising compounds for future in vivo investigations, because of their potential antioxidant activities in vitro.     

LANGERHANS CELL HISTIOCYTOSIS: Retrospective Evaluation of 123 Patients at a Single Institution

The aim of this study was to retrospectively evaluate clinical characteristics at diagnosis and outcome of patients with Langerhans cell histiocytosis (LCH). From October 1987 to March 1996, 133 patients with confirmed LCH were admitted to Hospital JP Garrahan in Buenos Aires (123 evaluable). Median age was 5 years (range 15 days to 18 years). Initial organ involvement included bone 114 patients, ear 34, skin 30, liver 18, lung 14, lymph nodes 14, spleen 12, diabetes insipidus 9, and bone marrow 2. Nineteen patients had organ dysfunction, pulmonary 14, hematological 14, and hepatic 12. Two groups were defined: Group A included patients with single system disease (unior multifocal) and group B multisystem (with or without organ dysfunction). In group A (n = 82), 24 patients were treated with chemotherapy (prednisone and vinblastine), 21 with surgery, 15 received radiotherapy, and 22 were only observed. Patients of group B ( n = 41) were treated with chemotherapy consisting of prednisone and vinblastine, DALHX 83, or LCH1-based chemotherapy. At a median follow-up of 3 years (range 1 month-8 5/12 years) 93% of patients of group A and 39% of group B survive free of reactivation. In group B, 22% had a reactivation and 39% died of progressive disease. Sequelae were detected in 35 patients (28%), which included diabetes insipidus in 17, hearing loss in 13, bony sequelae in 11, sclerosing cholangitis in 6, and lung fibrosis with bullae in 6. Two patients had a subsequent malignant disease. A total of 17 (14%) patients died and 16 of them belonged to the group B: 13 died of progressive disease, 2 due to sclerosing cholangitis (with sepsis in one case and encephalitis in the other one), 1 with progressive disease and associated myelofibrosis, and 1 patient of group A with active disease and brain stem tumor. Patients who had organ dysfunction had a reactivation free survival of 32%. All these patients survived with sequelae. Logistic regression analysis showed that organ dysfunction and hematological involvement had significant predictive values in relation to death. Patients of group A had an excellent survival rate, whereas in those of group B a high mortality was found, especially in the subgroup of patients with organ dysfunction. Lahey's criteria should be revised. Sequelae were also more common in this group.