Daniel F Sousa

Universidade Federal do Ceará, Fortaleza, Estado do Ceara, Brazil

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Publications (7)9.16 Total impact

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    ABSTRACT: In the present study, a practical activity is proposed to adopt an experimental approach to demonstrate the relationship between the equilibrium potential for K(+) and transmembrane electrical potential without glass micropipettes. A conventional setup for recording contractile activity of isolated smooth muscle preparations was used based on the events elegantly described by Somlyo and Somlyo in the 1960s. They showed that, in response to a given stimulus, smooth muscle cells may contract, recruiting electromechanical or pharmacomechanical coupling by mechanisms that involve, or not, changes in transmembrane potential, respectively. By means of contractions and relaxations of a ring-like preparation from the rat mesenteric artery, it is possible to observe the functional consequences of handling K(+) concentration in the extracellular compartment and the effects caused by opening K(+) channels in that preparation, which are significant when the cell membrane establishes an electrical potential difference between intra- and extracellular compartments (driven mainly by K(+) permeability under resting conditions). The effects observed by students fit well with values predicted by Nernst and Goldman-Hodgin-Katz equations, and we demonstrated that the activity is able to improve students' comprehension regarding basic principles of bioelectricity.
    AJP Advances in Physiology Education 08/2012; · 1.22 Impact Factor
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    ABSTRACT: Bixa orellana L., urucum, or urucu, a native tropical tree of Central and South American rain forests is used to treat various diseases in popular medicine. In Ceará, Northeast of Brazil, the seeds of urucum have been used for the treatment of high lipid blood levels. The present study investigated the effects of the aqueous extract from Bixa orellana seeds (AEBO) in mice with hyperlipidemia induced by tyloxapol, fructose and ethanol. In hyperlipidemia induced by Triton WR1339, 400 and 800 mg/kg AEBO reduced triglycerides (TG) serum levels at 24 h and 48 h. In the study of hypertriglyceridemia induced by fructose, AEBO in doses of 400 mg/kg and 800 mg/kg reduced TG levels by 48.2% and 48.7%, respectively. Finally, the ethanol experimental model with 400 mg/kg AEBO promoted a reduction of 33.6% of TG levels, while the 800 mg/kg concentration reduced hypertriglyceridemia in 62.2%. In conclusion, the aqueous extract of the seeds of Bixa orellana was capable of reversing the hypertriglyceridemia induced by Triton, fructose and ethanol, demonstrating a hypolipidemic effect. However, further studies are necessary to discover the precise mechanism of action. Copyright © 2012 John Wiley & Sons, Ltd.
    Phytotherapy Research 03/2012; · 2.07 Impact Factor
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    ABSTRACT: The therapeutic potential of toxins has aroused great interest in the scientific community. Microbial resistance is a serious current public health problem, in part because of the wide use of antimicrobial drugs. Furthermore, there are several problems in the treatment of parasitic diseases such as leishmaniosis and Chagas' disease, including the low efficacy in some clinical phases of the diseases and the loss of effectiveness of benzonidazole in the chronic phase of Chagas' disease. In this context, the aim of this work was to study the antimicrobial and antiparasitic effects of Bothropoides lutzi total venom (BltTV). The venom exerted an antibacterial effect on S. aureus, with MIC=MLC=200 microg/mL. The inhibitory effects of BltTV on promastigote forms of Leishmania amazonensis and L. chagasi were assessed by counting of viable cells after incubation with BltTV. IC50 values of 234.6 microg/mL and 61.2 microg/mL, were obtained, respectively. Furthermore, the venom repressed epimastigote forms of Trypanosoma cruzi growth. Finally, BltTV was verified to affect murine peritoneal macrophages, causing a cytotoxic effect at the highest concentrations (100 and 50 microg/mL). In conclusion, Bothropoides lutzi venom demonstrated antibacterial and antiparasite effects, suggesting that the venom contains some substance(s) of therapeutic value.
    Natural product communications 01/2012; 7(1):71-4. · 0.96 Impact Factor
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    ABSTRACT: Sertraline is often prescribed to patients suffering with end stage renal disease, but its action on kidney has not been investigated. We aimed to investigate the pharmacological action of sertraline on rat kidney with emphasis on the underlying mechanisms involved in the vascular actions of the drug. The effects of sertraline were evaluated in rat isolated perfused kidneys and on ring preparations of mesenteric or segmental rat renal artery. In kidneys, sertraline prevented the effects of phenylephrine on perfusion pressure, glomerular filtration rate, urinary flow and renal vascular resistance. In mesenteric rings sertraline inhibited phenylephrine-induced contractions with potency 30-times lower than verapamil. Sertraline reversed sustained contractions induced by phenylephrine or 60mm K(+) within a similar concentration range. In segmental isolated rings, sertraline also reversed contractions induced by phenylephrine or 60mm K(+) with the same concentration range, but with higher potency compared with mesenteric preparations. Under Ca(2+) -free conditions, sertraline did not change the intracellularly-mediated phasic contractions induced by phenylephrine or caffeine. Sertraline was ineffective against contractions induced by extracellular Ca(2+) restoration after thapsigargin treatment and Ca(2+) store depletion with phenylephrine. Conversely, sertraline decreased the contractions induced by Ca(2+) addition in tissues under high K(+) solution or phenylephrine plus verapamil. In rat isolated kidneys and in rat ring preparations of mesenteric or renal vessels, sertraline had antispasmodic effects that appeared to be caused by a direct action on vascular smooth muscle cells. Its actions were ineffective against Ca(2+) -releasing intracellular pathways, but appeared to interfere with sarcolemmal Ca(2+) influx with reduced permeability of both receptor- and voltage-gated Ca(2+) channels.
    The Journal of pharmacy and pharmacology. 09/2011; 63(9):1186-94.
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    ABSTRACT: In the search for potential antiobese agents from natural sources, this study investigated the effects of betulinic acid (BA), a pentacyclic triterpene from Clusia nemorosa L. (Clusiaceae), in mice on a high-fat diet (HFD). Adult male Swiss mice (n = 8) treated or not with BA (50 mg/L, in drinking water) were fed a HFD during 15 weeks. Mice treated with BA and fed a HFD showed significantly (P < 0.05) decreased body weights, abdominal fat accumulation, blood glucose, plasma triglycerides, and total cholesterol relative to their respective controls fed no BA. Additionally, BA treatment, while significantly elevating the plasma hormone levels of insulin and leptin, decreased the level of ghrelin. However, it caused a greater decrease in plasma amylase activity than the lipase. These findings suggest that BA has an antiobese potential through modulation of fat and carbohydrate metabolism, and it may be a suitable lead compound in the treatment of obesity.
    Journal of Agricultural and Food Chemistry 09/2009; 57(19):8776-81. · 2.91 Impact Factor
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    ABSTRACT: Hepatoprotective activity of Croton zehntneri Pax & Hoffman (Euphorbiaceae) leaf essential oil (EOCz) was evaluated against single dose of acetaminophen-induced (500 mg/kg, p.o.) acute hepatotoxicity in mice. EOCz significantly protected the hepatotoxicity as evident from the activities of serum glutamate pyruvate transaminase (GPT), serum glutamate oxaloacetate transaminase (GOT) activities, that were significantly (p<0.01) elevated in the acetaminophen alone treated animals. Histopathological examinations of liver tissue corroborated well with the biochemical changes. Hepatic steatosis, hydropic degeneration and necrosis were observed in the acetaminophen treated group, while these were completely absent in the standard and EOCz treated groups. In conclusion, these data suggest that the Croton zehntneri essential oil can prevent hepatic injuries from acetaminophen-induced hepatotoxicity in mice.
    Records of Natural Products. 01/2008;
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    ABSTRACT: Medication noncompliance has a harmful impact on reaching therapeutic goals of delaying the progression of chronic kidney disease (CKD). The aim of the present study is to calculate the prevalence of medication noncompliance and to identify medication noncompliance-associated factors in CKD. A cross-sectional study was performed with 130 CKD patients from a university nephrology outpatient clinic, mean age 48.8 +/- 15.8 years, who were continuously self-administering an antihypertensive or immunosuppressive drug, and who were neither on dialysis nor had received a kidney transplant. Noncompliance was measured through self-report (during an interview) and physician assessment. Patients were considered noncompliers if noncompliance had been detected by any of these methods. Sociodemographic, clinical and laboratory and medication characteristics were surveyed, as well as patients' knowledge regarding prescribed medicines and opinions of the quality of the health care service provided. Prevalence of medication noncompliance was 36.9% (95% confidence interval [95% CI], 28.6%-45.8%). Lack of access to medicines was the most commonly reported problem with medication use (62.5%). Multiple logistic regression analysis showed that patients' insufficient knowledge regarding prescribed medicines (p=0.040) and bad opinions of the quality of the provided health care service (p=0.027) were independently associated with noncompliance. Medication noncompliance prevalence was high among the patients studied. Lack of access to medicines remains an important public health problem. The noncompliance-associated factors identified in CKD were the patients' poor knowledge regarding the pharmacotherapy and dissatisfaction with the health care service provided.
    Journal of nephrology 01/2008; 21(3):354-62. · 2.02 Impact Factor