Baldomero Antonio Kato da Silva

Castor oil polyurethane containing silica nanoparticles as filling material of bone defect in rats

PURPOSE To evaluate the biologic behavior of the castor polymer containing silica nanoparticles as a bone substitute in diafisary defect. METHODS Twenty seven male Rattus norvegicus albinus Wistar lineage were submitted to bone defect filled with castor oil polymer. Three experimental groups had been formed with nine animals each: (1) castor oil polymer containing only calcium carbonate; (2) castor oil polymer with calcium carbonate and doped with 5% of silica nanoparticles; (3) castor polymer with calcium carbonate doped with 10% of silica nanoparticles; 3 animals of each group were submitted to euthanasia 15, 30 and 60 days after experimental procedure, and their femurs were removed to histological evaluation. RESULTS there was bone growth in all the studied groups, with a greater tendency of growth in the group 1. After 30 days all the groups presented similar results. After 60 days a greater amount of fibroblasts, osteoblasts, osteocytes and osteoclasts in group 3 was observed, with integrated activity of 3 kinds of cells involved in the bone activation-reabsorption-formation. CONCLUSIONS The castor polymer associated to the silica nanoparticles is biocompatible and allows osteoconduction. The presence of osteoprogenitors cells suggests silica osteoinduction capacity.

Experimental model of pulmonary carcinogenesis in Wistar rats

PURPOSE To elaborate an experimental model of pulmonary carcinogenesis in Wistar rats. METHODS Male Rattus norvegicus albinus, Wistar lineage were carried through an intra-pulmonary instillation of the Benzo[a]pyrene (B[a]P) dilution in alcohol 70%, a polycyclic aromatic hydrocarbon widely known by its power of tumoral induction. Three experimental groups had been formed with 08 animals each: Control Group (Alcohol 70%); B[a]P Group 10 mg/kg; e B[a]P Group 20mg/kg, submitted to euthanasia 08, 10, 12 and 14 weeks after the experimental procedure. The pulmonary sections had been colored by hematoxilin-eosin (HE) and submitted to the morphometrical analysis to describe the tissue alterations. RESULTS The presence of diffuse inflammatory alterations was observed in all groups; however, at the analysis of the pulmonary tissue of the experimental groups had been observed hyperplasic alterations (BALT hyperplasia), and in one of the animals of the experimental group 20mg/kg (12 weeks) was noticed the presence of cellular epithelial tracheal pleomorphism, suggesting the adenocarcinoma formation in situ. CONCLUSION The main secondary alterations to the intra-pulmonary instillation of B[a]P in Wistar rats were: cellular proliferation, inflammatory alterations of several degrees and nodular lymphoid hyperplasias. The association of an activator agent of the pulmonary metabolic reply is necessary to establish the ideal reply-dose to the development of the lung cancer.

Usefulness of argyrophilic nucleolar organizer regions in detection of lung cells alterations after benzo[a]pyrene instillation

PURPOSE To verify the relationship between AgNOR expression and lung tissues changes of Wistar rats after pulmonary instillation of benzo[a]pyrene (B[a]P). METHODS Male Rattus norvegicus albinus,Wistar lineage were given a single intrapulmonary instillation of B[a]P at doses of 10 and 20 mg/kg in a volume of approximately 0.3 ml. After 7 and 21 days the rats were killed and the lung slices submitted to a histological technique of AgNOR. AgNOR dots were quantified and the result analyzed by statistical tests; p < or = 0.05 was considered significant. RESULTS The mean values of AgNOR dots for the experimental groups 10/7 (1.51+/-0.86) and 10/21 (1.84+/-0.13) were statistically different (p = 0.009). Among the groups 20/7 (1.63+/-0.11) and 20/21 (2.48+/-0.28) was observed statistically significant difference (p = 0.003). CONCLUSION The AgNOR technique can be useful in identification of cells changes induced by B[a]P.

Effect of Ischemic Postconditioning and Atorvastatin in the Prevention of Remote Lung Reperfusion Injury

Objective The aim of the present study was to evaluate the ability of ischemic postconditioning, atorvastatin and both associated to prevent or minimize reperfusion injury in the lung of rats subjected to ischemia and reperfusion by abdominal aortic clamping. Methods We used 41 Wistar norvegic rats, which were distributed into 5 groups: ischemia and reperfusion (I/R), ischemic postcondictioning (IPC), postconditioning + atorvastatin (IPC+A), atorvastatin (A) and SHAM. It was performed a medium laparotomy, dissection and isolation of the infra-renal abdominal aorta; except for the SHAM group, all the others were submitted to the aortic clamping for 70 minutes (ischemia) and posterior clamp removal (reperfusion, 70 minutes). In the IPC and IPC+A groups, postconditioning was performed between the ischemia and reperfusion phases by four cycles of reperfusion and ischemia lasting 30 seconds each. In the IPC+A and A groups, preceding the surgical procedure, administration of 3.4 mg/day of atorvastatin was performed for seven days by gavage. After the surgical procedure, the right caudal lobe was removed from the lung for histological study, using tissue injury score ranging from grade 1 (normal tissue) to grade 4 (intense lesion). Results The mean lung injury was 3.6 in the I/R group, 1.6 in the IPC group, 1.2 in the IPC+A group, 1.2 in the A group, and 1 in the SHAM group (P<0.01). Conclusion Ischemic postconditioning and atorvastatin were able to minimize lung reperfusion injury, alone or in combination.

The effect of Sebastiania hispida gel on wound model infected by methicillin resistant Staphylococcus aureus

Medicinal plants are an alternative for the treatment of infected wounds. The objective of this study was to evaluate the efficacy of Sebastiania hispida in an animal model with a wound infected by Staphylococcus aureus. The crude ethanol extract (ExtEtOH) of S. hispida underwent phytochemical analysis, quantification of metabolites and antibacterial activity analysis performed using S. aureus. Wistar rats were used to test healing activity, and the groups evaluated comprised gels of ExtEtOH at the concentrations 0.2 and 2% compared with control groups. Animals were inoculated with the bacteria S. aureus resistant to methicillin. The treatment periods were of 3 and 21 days. Macroscopic and microscopic analysis were conducted and data were submitted to analysis of variance (p < 0.05). Phytochemical and quantification analysis indicated that phenolic compounds and flavonoids are the major constituents, followed by tyterpenes. ExtEtOH 0.2% was the most effective gel against the growth of strains of S. aureus. Histological wound and regression analysis showed that ExtEtOH gels (0.2% and 2%) were similar and effective in promoting wound healing. In the quantification of collagen fibers, the animals from all groups showed a high amount of thick collagen fibers. Thus, ExtEtOH gels based on the shoots of S. hispida can be used for the treatment of infected wounds as a complementary therapy for infected wound closure and further assays are required with other means. The healing effectiveness may be due to the high content of phenolics, flavonoids and triterpenes.

ATORVASTATIN CAN PREVENT HEPATIC REMOTE REPERFUSION INJURY

ABSTRACT Background: Some studies have shown that statins have a promising effect on protection against reperfusion injury. Aim: To evaluate the ability of ischemic postconditioning, statins and both associated to prevent or minimize reperfusion injury in the liver of rats subjected to ischemia and reperfusion by abdominal aorta clamping. Method: Were used 41 Wistar rats, which were distributed into five groups: ischemia and reperfusion (I/R), ischemic postcondictioning (IPC), postconditioning + statin (IPC+S), statin (S) and Sham. It was performed a medium laparotomy, dissection and isolation of the infra-renal abdominal aorta; excepting Sham group, all the others were submitted to the aorta clamping for 70 min (ischemia) and posterior clamping removing (reperfusion, 70 min). In the IPC and IPC+S groups, postconditioning was performed between the ischemia and reperfusion phases by four cycles of reperfusion and ischemia lasting 30 s each. In IPC+S and S groups, preceding the surgical procedure, administration of 3.4 mg/day of atorvastatin was performed for seven days by gavage. The left hepatic lobe was removed for histological study and euthanasia was performed. Results: The mean hepatic injury was 3 in the I/R group, 1.5 in the IPC group, 1.2 in the IPC+S group, 1.2 in the S group, and 0 in the SHAM group. The I/R group had a higher degree of tissue injury compared to the others in the statistical analysis and there was no difference between the others (p<0.01). Conclusion: Ischemic postconditioning and atorvastatin were able to minimize hepatic reperfusion injury, either alone or in combination.

Influência do aumento do tempo inspiratório na ventilação pulmonar de pacientes submetidos à ventilação mecânica na modalidade pressão controlada

BACKGROUND AND OBJECTIVES: The mechanical ventilator support is one of the main used modalities of support in intensive therapy. In the modality of predetermined pressure, the maximum pressure is regulated, but the current volume (VT) is a complex function of the applied pressure and its speed to reach the pressure-target, of the available breathing time and the resistance to the breath. This paper has as objective to evaluate the influences of the increment of the breathing time in the pulmonary ventilation. METHODS: The study was carried through in the Adult ICU of the Regional Hospital of Mato Grosso do Sul, located in Campo Grande. They had been enclosed individuals adult, both genders, between 16 and 84 years, submitted to the mechanical ventilation in controlled pressure mode or in controlled-watched mode. The breathing time was adjusted in 1 sec, developing in 0.2 sec until the boundary-value of 1.6 sec. The tidal volume (VT) and the volume minute (VE) had been evaluated of 13 patients in the breathing times of 1s; 1.2s; 1.4s and 1.6s. RESULTS: In the mean of VT and VE an increasing increase was observed after-increment of the breathing time. We did not find in consulted literature, data which correlated the breathing time with alterations in the current volume. CONCLUSIONS: The increment of the breathing time in the ventilation for pressure control can have influence in the determination of the current volume offered to the patient.