Marina Pacheco Miguel

Angiogenic activity of Calendula officinalis flowers L. in rats

PURPOSE In this work, angiogenic activity of Calendula officinalis L. (Asteraceae) ethanolic extract and dichloromethane and hexanic fractions were evaluated, considering medicinal properties, especially healing activity, are attributed to this plant. METHODS Models using 36 rats and 90 embryonated eggs were used to evaluate healing and angiogenic activities of extracts and fractions of the plant, through the induction of skin wounds and the chorioallantoic membrane, respectively. The effect of vascular proliferation was also tested from the study to verify the intensity of expression of vascular endothelial growth factor (VEGF) in cutaneous wounds in rats. RESULTS The angiogenic activity of the extract and the fractions was evidenced in both experimental models. It was verified that this effect is not directly related to the expression of VEGF and it could be associated to other pro-angiogenic factors. CONCLUSION The healing activity referred to C. officinalis is related, among other factors, to its positive effect on angiogenesis, characterized by the induction of neovascularization.

Use of chitosan membrane associated with polypropylene mesh to prevent peritoneal adhesion in rats.

The correction of wall abdominal defects often requires the use of implants such as polypropylene meshes. In spite of presenting good tissue acceptance, these biomaterials can migrate to adjacent viscera, promote enterocutaneos fistulas, tissue adherence and visceral erosions. In this work, the barrier effect of chitosan films associated with polypropylene meshes on adhesion formation experimentally induced in Wistar rats was evaluated. The animals were divided into two groups with 10 animals each. Animals in the CPP group were implanted with chitosan films associated with polypropylene meshes, whereas the ones in the PP group received only polypropylene meshes. After 8 days, the animals were submitted to euthanasia using CO(2) and a descriptive study focusing adhesion formation, visceral involvement with sutures and mesh peritonization was performed. Also, subimplanted material was collected for histopathology analysis. The results showed that the CPP group presented weak adhesions to the omentum over the stitch knots in eight animals. In all animals, the meshes were peritonized, not allowing their visualization after removing the chitosan films. In the PP group, six animals presented intestinal adhesions to the meshes and, in one of them, hepatic adhesion to the mesh was observed, besides omentum adhesion on more than 50% of the mesh area. The protective effect of chitosan films when sutured over polypropylene meshes, as well as no exacerbation of inflammation associated to the peritoneal lesions was statistically demonstrated. Therefore, chitosan films can indeed minimize the formation of peritoneal adhesions induced by polypropylene meshes in rats.

The Fate of the Tumor in the Hands of Microenvironment: Role of TAMs and mTOR Pathway

Since 2000, written with elegance and accuracy, Hanahan and Weinberg have proposed six major hallmarks of cancer and, together, they provide great advances to the understanding of tumoral biology. Our knowledge about tumor behavior has improved and the investigators have now recognized that inflammatory microenvironment may be a new feature for the tumor entities. Macrophages are considered as an important component of tumoral microenvironment. Biologically, two forms of activated macrophages can be observed: classically activated macrophages (M1) and alternative activated macrophages (M2). Despite the canonical pathways that control this puzzle of macrophages polarization, recently, mTOR signaling pathway has been implicated as an important piece in determining the metabolic and functional differentiation of M1 and M2 profiles. Currently, it is believed that macrophages related to tumoral microenvironment present an “M2-like” feature promoting an immunosuppressive microenvironment enhancing tumoral angiogenesis, growth, and metastasis. In the present review we discuss the role of macrophages in the tumor microenvironment and the role of mTOR pathway in M1 and M2 differentiation. We also discuss the recent findings in M1 and M2 polarization as a possible target in the cancer therapy.

Ovarian blood vessel occlusion as a surgical sterilization method in rats

PURPOSE To evaluate the female sterilization by occlusion of the ovarian blood flow, using the rat as experimental model. METHODS Fifty-five females rats were divided into four groups: I (n=10), bilateral ovariectomy, euthanized at 60 or 90 days; II (n=5), opening the abdominal cavity, euthanized at 90 days; III (n=20), bilateral occlusion of the ovarian blood supply using titanium clips, euthanized at 60 or 90 days; and IV (n=20), bilateral occlusion of the ovarian blood supply using nylon thread, euthanized at 60 or 90 days. The estrous cycle was monitored by vaginal cytology. After euthanasia, the reproductive tissues were evaluated histologically. RESULTS Ovarian atresia was identified macroscopically at 60 days after surgery in the rats in groups III and IV; however, most of the rats in group III maintained cyclicity. Histology of the tissues from group IV revealed that the ovarian tissue was replaced by dense fibrous connective tissue that was slightly vascularized and that intact follicles were absent by 90 days. CONCLUSION Ovarian blood vessels occluded caused ischemia, leading to progressive tissue necrosis, and bilateral occlusion using a nylon ligature is a viable method for surgical sterilization.

Intoxicação crônica por cobre em ovinos: conduta para o diagnóstico conclusivo

The present work describes the clinical signs and anatomopathological findings of chronic copper toxicities in a Texxel breed sheep and defines the optimal diagnostic procedure for confirmation of the disorder. A sheep was sent to pathology analysis service with a history of apathy, hemoglobinuria and death within two to three days. Necropsy showed jaundice and subcutaneous edema, enlarged yellow liver and dark kidneys. The histologic examination showed random zonal necrosis, marked necrosis in the liver and tubular epithelial and orange-brown spotted hyaline cylinders in the collecting tubules of the kidneys. The dietary history, sensitivity of species/breed, clinical, macroscopic and microscopic alterations suggested the framework of chronic copper poisoning. Diagnostic confirmation was only possible after staining copper pigments trough the Ulzmann technique and quantification of copper in the dry liver and kidney, which were higher than normal levels.

Clinical and histological effects of the temporary occlusion of the rabbit nasolacrimal duct and point using cyanoacrylate adhesives

The objective of this study was to evaluate the clinical and histological effects of occluding the nasolacrimal ducts and points of rabbits. For this study, 20 adult New Zealand rabbits, both males and females, weighing 3.2±0.4kg were allocated into two groups for n-butyl-cyanoacrylate occlusion (GB, n=10) or 2-octyl-cyanoacrylate occlusion (GO, n=10). The contralateral eyes served as the controls. The persistence of tears was evaluated daily using the Schirmer I test. Discomfort, eye discharge, epiphora, and conjunctival hyperemia were assessed prior to the procedure (T0) and during the 14 subsequent days (T1-T14). On days seven and 14, five animals from each group were euthanized, and their nasolacrimal ducts were collected, processed and analyzed by histology. In the GB group, the Schirmer test values differed from that at T0 at all of the subsequent time points, whereas there was no difference in the values observed from the GO group. Compared with the corresponding controls, the GO and GB groups differed significantly at almost all of the time points. When comparing the treatment groups, differences were found at T6, T7, T9, T10, T11, T12 and T14, with higher Schirmer values in the GB group. Epiphora was observed in the GB group from T1 to T8 and in the GO group from T1 to T6. Within seven days post-occlusion, histology revealed a moderate foreign body reaction, with marked necrosis and sloughing of the canalicular epithelium, in the GO group, which was absent at day 14. In the GB group, a marked inflammatory reaction and a mild foreign body reaction were found at day seven, and the foreign body reaction was prevalent at day 14. This study demonstrated that both adhesives were effective in obstructing the nasolacrimal ducts and points of rabbits and that their application and handling are easy and free of complications. However, both adhesives promoted inflammatory and foreign body reactions that evolved to repair and regeneration at day 14 of evaluation.

Característica leucocitária, relação albumina/globulina, proteína plasmática e fibrinogênio de bovinos da raça Nelore, confinados e terminados a pasto

This research aimed to evaluate the changes in the white blood cell count and some serum proteins of confined cattle (CC) and grass cattle (GC). From the 120 blood samples collected, 60 were obtained from confined Nelore male bovines and 60 from animals with the same characteristics but managed extensively. Samples were obtained at the moment of slaughter. Parameters studied were the white blood cell count, serum albumin/globulin ratio and concentration of plasma fibrinogen. Descriptive statistics was used in the analysis of the data, and the averages, standard deviation and coefficient of variation calculated for all parameters evaluated. The comparisons between averages were made by non-parametric test. The grazing cattle showed higher levels of globulin and fibrinogen when compared to the confined ones (globulin: GC=3.29g dL-1±0.76; CC=2.99g dL-1±0.60 and Fibrinogen: GC=872mg dL

Evaluation of wound healing treated with latex derived from rubber trees and Aloe Vera extract in rats

PURPOSE: To compare the use of latex derivative and Aloe vera extract to wound healing. METHODS: Twenty one rats were randomly divided into three groups and each one had a wound made by incision. The treatment consisted in: derivative of latex (GL), Aloe vera extract (GA) and saline solution (GC). The wound area was measured on the 7th, 14th and 21st days and macroscopic and microscopic evaluation were done. RESULTS: The comparison between the measurements of the wounds presented statistical difference in GC and GA from the 7th day of evaluation and GL from the 14th day. The extent of the wound was significantly smaller by the 7th day in GL. Histologically, in GL, the neovascularization was significant on the 7th, 14th and 21st days. On the 21st day the scar was large and little mature. In GA and GC, the findings were similar on the 7th, 14th and 21st days with a slight better organization of skin and collagen on the 21st in GA. CONCLUSIONS: Statistical analysis did not allow for the definition of the best topical agent. The latex had the highest angiogenesis, but a possible foreign body granuloma. Aloe vera has revealed a healing process adequated temporally in histology.

Expressão de Cyr61 em glândulas mamárias normais e neoplásicas de cadelas

Mammary glands are the most usual sites of tumors in bitches, representing 25 to 30% of all types of cancer. During cancer genesis, several genetic changes alter the expression of different proteins like Cyr61, a peptide involved in cell proliferation and angiogenesis. This work aimed to determine through immunohistochemistry the expression profile of Cyr61 in normal and neoplastic mammary glands from bitches. So, 10 cases of each diagnose were selected: simple adenoma, complex carcinoma, simple solid carcinoma and fragments of normal mammary glands, in a total of 40 cases. Sections were subjected to immunohistochemistry, employing primary antibodies directed Cyr61. Cyr61 labeling of normal mammary epithelial cells is probably linked to its role in apoptosis and cellular proliferation. The labeling was more intense in normal and adenoma fragments and was discrete in the labeling malignant tumor sections, a different feature of expression from previously reports in human breast cancer. Immunohistochemical analysis with polyclonal antibody Cyr61 demonstrated the constitutive expression of the protein and contributed to neoplastic research alternative for tumors in bitches.