Biomedical Engineering Research

  • Detailed Computation of Air-Conditioning Modality within Chimpanzee Nasal Airways

    Nasal cavity of primates and other animals has been reported in many research works. Lots of the previous studies focused on the nasal airflow but few of them considered the internal nasal air-conditioning phenomena. In this study, we investigated the air-conditioning modality within an anatomically accurate computer nasal airways model of a healthy female adult chimpanzee. The finite volumes method was used to compute a steady laminar inspiratory flow with physiological flow rate of 1.4 m/s, mimicking breathing at rest state. Detailed distributions of air-conditioning in lower, middle and upper airways of the left and right nasal cavities were investigated. The numerical simulation revealed that air-conditioning pattern inside the chimpanzee nasal cavity varies depending to the nasal topology.

  • Evaluation of antioxidant and gastroprotective activities of ethyl acetate extract of Avicennia schaueriana.

    Introduction: Brazilian flora has a great biodiversity and some of these plants are used in folk medicine. Avicennia schaueriana, popularly known as black mangrove, is an endemic specie of mangrove vegetation belonging to the Acanthaceae family. The species of the genus Avicennia are widely used by traditional communities for the treatment of tumors, rheumatism, ulcers and wound healing. Objectives: To evaluate the antioxidant and gastroprotective properties of the ethyl acetate extract of Avicennia schaueriana. Methodology: The ethyl acetate extract of the leaves of A. schaueriana (As-AcEOt) was obtained by maceration, and afterwards the phytochemical prospecting was evaluated by thin layer chromatography (TCL). The antioxidant potential of the As-AcEOt was evaluated by free radical scavenging method ABTS+ (2,2-azobis – (3-ethylbenzthiazoline-6-sulfonate). The gastroprotective activity of As-AcEOt (50, 100 and 200 mg/kg) was analyzed by the ethanol-induced ulcer method in Wistar rats. The myeloperoxidase (MPO) levels and histopathological analysis were evaluated in gastric mucosa of the animals treated with As-AcEOt submitted to the model of ulcer induced by ethanol. Results and Discussion: Through TCL was observed the presence of terpenoids, flavonoids and tannins in the extract. The As-AcEOt exhibited antioxidant activity with 73.23% inhibition of the radical ABTS+. In the gastroprotective activity, the As-AcEOt reduced the ulcerative lesion index (ULI), with percentages of ULI of 83.8, 88.5 and 86.9% for the doses of 50, 100 and 200 mg/kg, respectively. The histological analysis showed that As-AcEOt preserved the gastric pits and it did not present hemorrhage and edema. Conclusion: This research showed that As-AcEOt has gastroprotective property, which may be related to antioxidant capacity of the phenolic compounds present in the extract. These results corroborate with the indication of popular use of this species in the treatment of gastric ulcers.

  • Metabolic and immunological modifications present in Alzheimer’s Disease

    Introduction: Alzheimer’s Disease (AD) is classified as progressive neurodegenerative and represents one of the main causes of dementia in the elderly. Its symptomatology is characterized by loss of memory, neuronal destruction and reduction of brain volume. The literature reports a series of metabolic and immunological changes that contribute to the progression of the disease. Objective: To carry out a review of the literature on metabolic and immunological modifications present in Alzheimer’s Disease. Methodology: 34 articles, published between 2008 and 2017, were pre-selected in the SciELO database, using the descriptors: Inflammation + Alzheimer’s Disease; Hypotheses + Alzheimer + Etiology; Alzheimer’s Disease + Lymphocytes; Metabolism + Alzheimer’s. After analysis of the abstracts, 4 articles were analyzed in full. Results and Discussion: The following metabolic alterations were observed in patients with AD: folic acid reduction, arginine reduction and increase of calcium influx to cell. Serum folic acid concentration is reduced in AD patients compared to healthy elderly individuals and has an inverse relationship with the amino acid homocysteine, which can cause apoptosis and increased oxidative stress, leading to cognitive damages that characterize the progression of the disease. Changes in NMDA receptors have also been observed, so glutamate is not reuptake and accumulates in the extracellular environment causing toxicity. In addition, as a consequence, there is a high influx of calcium leading to toxicity and apoptosis of neuronal cells. In relation to the immunological alterations, were found reduction of lymphocytes, increase of interleukin and increase of microglia, which in high quantity produce neurotoxins that contribute to the neuropathogenic mechanism of AD. In relation to the level of arginine, the amino acid involved with the energetic process, it was observed that some cells of the immune system consume it abnormally, resulting in the energy decrease and slowness of metabolism, characteristic of AD. Conclusion: Metabolic and…

  • Evaluation of lectin extracted from Canavalia brasiliensis on the neuropsychomotor system of murine

    Introduction: Lectins are a class of proteins extracted from the seeds of Canavalia brasiliensis (Lectin ConBr). Its anti-neoplastic activity has been studied in experimental models. Aim: To evaluate the neuropsychomotor effect of Lectin ConBr in vivo in murine. Methods: Thirty Swiss mice were divided into three groups: GCcontrol (n = 10) administered saline solution; G1experimental (n = 10) 50mg/kg and G2experimental (n = 10) 300mg/kg of Lectin ConBr. The neuropsychomotor analysis was performed by The Open Field Test, 4 and 24 hours after treatment. The statistic was performed by Student’s t-test. Results and Discussion: In the CG, the results obtained after 4h were: ambulation 55.4 ± 16.8; self-cleaning 4.8 ± 1.3; lifting 21.5 ± 3.41 and defecation 0.6 ± 0.5. G1: ambulation 43.4 ± 29.11; self-cleaning 3.4 ± 1.6; lifting 8.0 ± 8.1 and defecation 0.2 ± 0.44. G2: ambulation 63.0 ± 14.58; self-cleaning 1.0 ± 0.7; lifting 12.8 ± 3.1 and defecation 0.2 ± 0.44. The results obtained after 24 hours were: GC: ambulation 62.2 ± 27.9; self-cleaning 2.6 ± 1.5; lifting 15.3 ± 5.8 and defecation 1.4 ± 0.5. G1: ambulation 32.0 ± 15.7; self-cleaning 1.8 ± 1.7; lifting 6.0 ± 6.0; defecation 0.6 ± 0.5. G2: ambulation 62.0 ± 30.1; self-cleaning 0.6 ± 0.5; lifting 16.8 ± 7.3 and defecation 0.4 ± 0.5*. ConBr did not alter the spontaneous movement of the mice after 4 hours, however, the self-cleaning act and the total number of lifting in the treated groups decreased. After 24 hours, it was observed that self-cleaning decreased at the dose of 300mg/kg, lifting was decreased at a dose of 50mg/kg and the number of fecal cakes was decreased at all doses, suggesting anxiolytic action without motor impairment. Conclusion: The results indicate an anxiolytic effect of ConBr on treated animals when compared to the control…

  • Cervical cancer: applications of genotyping for the screening in human papilomavirus (HPV)

    Introduction: Cervical cancer is considered a serious public health problem, especially in underdeveloped countries. The causal factor of the disease is infection of the vaginal mucosa by human papillomavirus (HPV). HPV consists of more than 130 genotypes, the genotypes of higher prevalence in histopathological diagnoses are subtypes 16 and 18. Currently diagnostic techniques such as pap smears and HPV test do not cover viral subtypes, important for identifying the presence of the high-risk genotypes in the sample, stopping the progression to cervical cancer. Genotyping consists of the secondary screening method for identification of viral subtypes, bringing promising prospects for the early diagnosis of the disease. Objective: To evaluate genotyping as an alternative for the early identification of the high risk HPV genotype as a possibility for the prevention of cervical cancer. Methodology: Electronic data platforms (MEDLINE, PubMed and Scopus) were consulted from 2012 to 2016, using the descriptors: “cervical cancer”, “HPV” and “genotyping”. Results and Discussion: With the applications of genotyping, it is possible to detect elements that indicate the presence of high-risk HPV subtypes in the positive samples in the initial screening techniques. Through the detection of the p16 and ki-67 proteins, which are expressed in the stages of the cell cycle, the decrease of these biomarkers indicates a deregulation in the cellular proliferation, indicating the oncogenic manifestation. The advancement of technologies has contributed to add improvements to screening programs and thus make them more effective in detecting women who have a greater potential for progression to cervical cancer. Conclusion: Although several techniques for identifying cancer caused by HPV have already been applied, they do not yet have coverage for a quick and accurate diagnosis of the viral genotype.

  • The role of inflammatory mediators in carcinogenesis

    Introduction: The process of carcinogenesis or tumor progression occurs slowly, which may take years until the formation of a visible tumor or an accumulation of abnormal, undifferentiated progenitor cells. Inflammation is a protective response of the body triggered by noxious stimuli. Studies report that the relationship between cancer and inflammation consists of the presence of inflammatory cells and inflammatory mediators in tumor tissues and angiogenesis. The inflammatory state contributes to tumor development through mechanisms such as: induction of genomic instability, stimulation of proliferation and resistance to apoptosis and induction of tumor angiogenesis. Objective: Introduce the most recent on the subject in the academic debate. Methodology: A bibliographical survey was carried out of the main academic journals with articles from the last five years. Results and Discussion: Studies have shown the frequent appearance of tumors in sites of chronic inflammation, besides the presence of inflammatory cells and mediators in tumor tissues, such as chemokines, cytokines and cyclooxygenase (COX), an enzyme responsible for the formation of important mediators including prostaglandins. Chemokine receptors are primarily responsible for leukocyte migration during inflammation and carcinogenesis, directly involved in the invasion, motility and survival of tumor cells. In relation to cytokines, TNF-α (tumor necrosis factor) stimulates growth. The presence of elevated serum levels of IL-6 in cancer patients was also observed. At the enzyme level, COX-2 overexpression is associated with increased angiogenesis, decreased apoptosis and immunosuppression in a variety of tumors. Conclusion: The cellular mediators of the inflammatory process are important agents in tumor tissues. These inflammatory changes act on cell proliferation and activation of angiogenesis, inhibiting adaptive immune responses.