The sodium pump (SP or Na+,K+-ATPase) is a membrane embedded protein complex that pumps 3 sodium ions out and 2 potassium ions into the cell per cycle and in so doing creates a cell membrane electrochemical potential. The membrane potential is critical for any functional cell. In the vasculature, reduction in the voltage potential causes vascular smooth muscle contraction and a narrowing of blood vessels (vasoconstriction) which can lead to increased blood pressure (hypertension). Substantial research over the past several decades has provided a vast amount of research on SP inhibitors, sometimes called endogenous digitalis-like factors (EDLF). Increased levels of these factors have been implicated in many hypertensive disorders including preeclampsia (PE), a life-threatening complication of pregnancy. It has been demonstrated that EDLF might be a causative factor in the pathophysiology of hypertension in PE. In order to elucidate EDLF production and regulation in PE, We developed a radioimmunoassay (RIA) measuring EDLF that could be applied to serum from pregnant women, placental homogenate and placental tissue culture. This assay employs Digibind, a commercially available Fab fragment derived from polyclonal antidigoxin antibodies that cross reacts with EDLF, as the primary antibody. Using Digibind RIA, we demonstrated that placenta is a source of EDLF production and regulation. Moreover, the identification of an inhibitor, ketoconazole and a substrate, 17-hydroxyprogesterone of the synthetic pathway of EDLF in placenta proved that this pathway shares steps with the steroid synthetic pathway. Some potential regulatory agents which have elevated levels in PE or be associated in PE and thus are thought to mediate PE, such as hydrogen peroxide, tumor necrosis factor-α (TNF-α) and hypoxia have also been demonstrated to be stimuli of EDLF production in placenta. These findings are helpful to the further study on EDLF synthesis and regulation in placenta. Once we elucidate the mechanisms, it could be easier to provide deeper insights into the pathogenesis of PE and subsequently develop earlier diagnosis and effective prevention of or therapeutic approaches to PE.

No description available.

No description available.

A digoxina é um dos medicamentos indicados para o tratamento de falência cardíaca. Possui janela terapêutica estreita, sendo responsável por casos de intoxicação. O único antídoto disponível para a desintoxicação é o anticorpo policlonal DigiFab®, no formato Fab. O seu uso é eficaz, porém de custo elevado. Clones bacterianos produtores de fragmento Fab monoclonal anti-digoxina foram obtidos previamente pelo nosso grupo, pela técnica de phage display. Neste trabalho as variantes Fab dos 4 clones foram expressas em E.coli para estabelecer o método para a purificação. Com a obtenção dos fragmentos Fab purificados, foi caracterizada a sua afinidade ao antígeno e especificidade, em ensaios de inibição por digoxina, digitoxina, digoxigenina e ouabaina. Os parâmetros cinéticos da ligação dos fragmentos Fab dos 4 clones e do DigiFab® foram avaliados por SPR. Nas condições experimentais, não foram verificadas diferenças significativas entre os produtos dos 4 clones e o comercial, demonstrando o potencial dos fragmentos Fab monoclonais obtidos como antídoto à digoxina. / Digoxin is a medication indicated for heart failure treatment. Its therapeutic window is narrow, being responsible for intoxication cases. The only antidote available for the detoxification is a polyclonal antibody - DigiFab® in Fab format. Its use is effective, but costly. Bacterial clones producing anti-digoxin monoclonal Fab fragments were previously obtained by our group using phage display technology. In this work the Fab variants of the 4 clones were expressed in E.coli to establish the purification method. The purified fragments were characterized regarding the affinity to the antigen and the specificity through inhibition assays with digoxin, digitoxin, digoxigenin and ouabain. The binding kinetic parameters of Fab fragments of the 4 clones and the commercial product to Dig-BSA conjugate were assessed by SPR. Under the experimental conditions no significant differences were observed among the 4 clones and the commercial product, demonstrating the potential of monoclonal Fab fragments as an antidote to digoxin.

In Part I we found that the CYP2C9 genotype appears to influence the diastolic blood pressure response to the angiotensin II-receptor antagonist irbesartan in patients with hypertension and left ventricular hypertrophy. Those with the *1/*2 genotype (slower metabolism) responded better than those with the *1/*1 genotype (normal metabolism), likely due to a slower elimination of the drug. We further found that a +9/-9 exon 1 polymorphism of the B2 bradykinin receptor gene – shown to affect mRNA expression - appears to influence the regression of left ventricular mass during therapy with irbesartan or the beta-blocker atenolol in the same patients. Subjects with the -9/-9 genotype (higher mRNA expression) had a greater regression than carriers of the +9 allele. In Part II we found that women on digoxin therapeutic drug monitoring have higher serum digoxin concentrations (SDCs) as compared to men (1.54±0.04 [nmol/L±SE] vs 1.20±0.05 [nmol/L±SE], p<0.001), which could be of importance since an SDC >1.4 nmol/L has been associated with increased mortality. We further found that coadministration of P-glycoprotein inhibitors with digoxin was common (47%) among the same patients, and that the SDC increased in a stepwise fashion with the number of P-glycoprotein inhibitors (20-60%). Lastly, we found that patients admitted to Swedish coronary care units with atrial fibrillation without heart failure and who had been given digoxin had a higher 1-year mortality than those not given digoxin (RR 1.44 [95% CI 1.29-1.60], adjustment made for potential confounders). In conclusion, Part I represents a further step in the pharmacogenomic prospect of tailoring antihypertensive therapy. Part II indicates that heightened attention to the digoxin-dose is warranted in women, that there is a need for awareness about P-glycoprotein interactions with digoxin, and that long-term therapy with digoxin is an independent risk factor for death among patients with atrial fibrillation without heart failure.

Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-17T19:55:14Z No. of bitstreams: 1 DISS_2015_Claodete Hasselstrom Neves.pdf: 1544628 bytes, checksum: c8448adc35211604eee744606435547c (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-27T17:11:37Z (GMT) No. of bitstreams: 1 DISS_2015_Claodete Hasselstrom Neves.pdf: 1544628 bytes, checksum: c8448adc35211604eee744606435547c (MD5) / Made available in DSpace on 2018-04-27T17:11:37Z (GMT). No. of bitstreams: 1 DISS_2015_Claodete Hasselstrom Neves.pdf: 1544628 bytes, checksum: c8448adc35211604eee744606435547c (MD5) Previous issue date: 2015-03-06 / O objetivo deste estudo foi investigar os efeitos da administração crônica de digoxina e do verapamil durante treinamento físico intervalado de alta intensidade (TFI) sobre o desempenho físico, capacidade funcional e morfologia cardíaca de ratos. Para tanto, 48 ratos Wistar, com 60 dias de idade, foram aleatoriamente distribuídos em 6 grupos(N=8/grupo): controle, não treinado (C), treinado, sem administração de droga (T), digoxina sem treinamento (DIGO), verapamil sem treinamento (VERA), treinado, com administração de digoxina (TDIGO) e treinado, com administração de verapamil (TVERA). A digoxina e o verapamil foram administrados via gavagem, na dose de 30μg/kg/dia e 5,0 mg/kg/dia respectivamente, durante todo o período experimental. Os grupos T, TDIGO e TVERA foram submetidos a um programa de TFI em esteira rolante durante 60 dias. Foi aplicado o teste de esforço progressivo máximo (TEM) e determinada a concentração sérica de lactato (LAC) sanguíneo. O TFI consistiu de sessões de corrida em esteira rolante 1 h/dia, 5 dias/semana por 60 dias. A intensidade de treino foi 80% da velocidade máxima (Vmáx) atingida no teste de esforço antes do TFI por 8 min e 20% da Vmáx por 2 min. A função cardíaca foi avaliada por ecocardiograma. Foi coletado o músculo esquelético, o músculo cardíaco e a gordura corporal total (GOR) para os dados anatômicos, o ventrículo esquerdo (VE) para análise histológica e o sangue para a análise bioquímica. A comparação entre os grupos foi realizada por meio da análise de variância (ANOVA) e Kruskal Wallis para o esquema de dois fatores independentes, complementada com o teste de Bonferroni, Tukey ou Dunn. O índice de significância considerado foi de 5%. A relação VE/peso corporal final (PCF), o diâmetro diastólico do VE (DDVE) e diâmetro sistólico do VE (DSVE) foram maiores no grupo TDIGO do que o grupo T e DIGO. Os parâmetros do TEM foram maiores e a concentração de LAC foi menor em ratos treinados em relação aos não treinados. A relação GOR/PCF foi menor no TDIGO e TVERA em relação ao DIGO e VERA, respectivamente. A relação VE/PCF foi maior no TVERA em relação ao VERA. O diâmetro interno do VE (DIVE) do grupo T, TDIGO e TVERA foram maiores em relação ao C, o TDIGO teve aumento em relação ao DIGO. O colesterol total e o LDL foram maiores no TDIGO comparado ao DIGO. A área do cardiomiócito foi maior nos grupos VERA e T comparados ao grupo C. Conclusão: O Treinamento intervalado promoveu hipertrofia cardíaca do tipo excêntrica. Entretanto, a administração concomitante de digoxina ou de verapamil não afetaram a morfologia cardíaca, a função cardíaca e o desempenho físico em ratos submetidos ao treinamento. / The aim of this study was to investigate the effects of chronic administration of cardiotonic (digoxin) and the calcium channel blocker (verapamil) during high-intensity interval exercise training (IET) on physical performance, functional capacity and cardiac morphology of rats. For this study, 48 Wistar rats, 60 days old, were randomly distributed into 6 groups (N = 8 / group): control, untrained (C), trained without drug administration (T), digoxin untrained (DIGO), verapamil without training (VERA), trained with digoxin administration (TDIGO) and trained with verapamil administration (TVERA). Digoxin and verapamil were administered by gavage at a dose of 30μg/kg/day and 5.0 mg.kg-1, respectively, throughout the experimental period. The groups T, TDIGO and TVERA underwent a IET program on a treadmill for 60 days. The progressive maximal exercise test was applied (TPM) and determined the serum concentration of lactate (LAC) blood. The IET consisted of sessions running on a treadmill 1 h/day, 5 days/week for 60 days. The training intensity was 80% of the maximum velocity (Vmax) achieved in the stress test before the TAI for 8 min and 20% of Vmax for 2 min. Cardiac function was assessed by echocardiography. Was collected skeletal muscle, cardiac muscle and total body fat (TBF) for anatomical data, the left ventricle (LV) for histological analysis and blood for biochemical analysis. The comparison between groups was performed using analysis of variance (ANOVA) or Kruskal Wallis for the two independent factors, complemented by the Bonferroni test, Tukey or Dunn. The significance level considered was 5%. The ratio VE final body weight (FBW), LV diastolic diameter (LVDD) and LV systolic diameter (LVSD) were higher in TDIGO group than the group T and DIGO. The parameters MET were higher and the concentration of LAC was lower in rats training in relation to the untrained. The relationship GOR/FBW was lower in TDIGO and TVERA compared to DIGO and VERA respectively. The ratio VE/FBW was higher in TVERA compared to VERA. The of the LV inside diameter (LVID) T group, TDIGO and TVERA were higher compared to C, TDIGO had increased compared to DIGO. Total cholesterol and LDL were higher in TDIGO compared to DIGO. The area of cardiomyocytes was higher in VERA and T compared to group C. Conclusion: TAI induced cardiac hypertrophy of the eccentric type. However, concomitant administration of digoxin or verapamil did not affect the cardiac morphology, cardiac function and physical performance in rats submitted to training.

A digoxina é um dos medicamentos indicados para o tratamento de falência cardíaca. Possui janela terapêutica estreita, sendo responsável por casos de intoxicação. O único antídoto disponível para a desintoxicação é o anticorpo policlonal DigiFab®, no formato Fab. O seu uso é eficaz, porém de custo elevado. Clones bacterianos produtores de fragmento Fab monoclonal anti-digoxina foram obtidos previamente pelo nosso grupo, pela técnica de phage display. Neste trabalho as variantes Fab dos 4 clones foram expressas em E.coli para estabelecer o método para a purificação. Com a obtenção dos fragmentos Fab purificados, foi caracterizada a sua afinidade ao antígeno e especificidade, em ensaios de inibição por digoxina, digitoxina, digoxigenina e ouabaina. Os parâmetros cinéticos da ligação dos fragmentos Fab dos 4 clones e do DigiFab® foram avaliados por SPR. Nas condições experimentais, não foram verificadas diferenças significativas entre os produtos dos 4 clones e o comercial, demonstrando o potencial dos fragmentos Fab monoclonais obtidos como antídoto à digoxina. / Digoxin is a medication indicated for heart failure treatment. Its therapeutic window is narrow, being responsible for intoxication cases. The only antidote available for the detoxification is a polyclonal antibody - DigiFab® in Fab format. Its use is effective, but costly. Bacterial clones producing anti-digoxin monoclonal Fab fragments were previously obtained by our group using phage display technology. In this work the Fab variants of the 4 clones were expressed in E.coli to establish the purification method. The purified fragments were characterized regarding the affinity to the antigen and the specificity through inhibition assays with digoxin, digitoxin, digoxigenin and ouabain. The binding kinetic parameters of Fab fragments of the 4 clones and the commercial product to Dig-BSA conjugate were assessed by SPR. Under the experimental conditions no significant differences were observed among the 4 clones and the commercial product, demonstrating the potential of monoclonal Fab fragments as an antidote to digoxin.

This research project explores the contribution of prenatal stress to the pathogenesis of autism as a neurobiological developmental disorder. The neurobiological impact of stress prior to the 28th week of gestation might produce structural neural changes, specifically regarding the cerebellum, the brain stem and limbic pathways, including the hippocampal area, which concept relates closely to the pathogenesis of autism. In this research project a significant focus is placed on prenatal hipothalamic-pituary-adrenal (HPA) activity due to the HPA axis’ interactivity with cortisol, digoxin and serotonin, as these biochemicals are significantly implicated in programmed foetal development, postnatal cortical behaviour, postnatal learning, as well as in functional impairment of socialization, communication and imagery associated with autism. Based upon the rationale of this research project and the conceptualisation of the topic of interest, the research problem was formulated as follows: In what unique ways does prenatal stress contribute to the pathogenesis of autism as a neurobiological developmental disorder? Sub questions included: Did the mother of the dizygotic twins experience significant stress during the period of gestation? What structural brain differences can be observed among the dizygotic twins at hand of MR-imaging? To which periods of prenatal development can these structural differences be related? How do these differences account for sensory, motor, cognitive, and affective behavioural differences among the dizygotic twins? What plasma differences can be observed among the dizygotic twins at hand of blood sampling? How does elevation of pre- and postnatal glucocorticoids relate to plasma difference among the dizygotic twins? How do these plasma differences account for sensory, motor, cognitive, and affective behavioural differences among the dizygotic twins? This research project represents quantitative research. The mode of inquiry is non-experimental at hand of a single dizygotic twin study. The following data generating strategies were employed: clinical intake interviews, administration of a diagnostic stress inventory and the 16-PF Questionnaire, MR-imaging, and the collection of blood plasma pathology results. / Dissertation (M.Ed)--University of Pretoria, 2006. / Educational Psychology / unrestricted

No description available.

Heart rate changes mediate the embryotoxic effect of antiarrhythmic drugs in the chick embryo A significant increase in cardiovascular medication use during pregnancy has occurred in recent years but only limited evidence on its safety profile is available. We hypothesized that drug-induced bradycardia is the leading mechanism of developmental toxicity. We tested metoprolol, carvedilol, or ivabradine for embryotoxicity and their acute effect on chick embryonic model. We used video microscopy and ultrasound biomicroscopy. Significant dose-dependent mortality was achieved in embryos injected with carvedilol and ivabradine. In ED4 embryos, metoprolol, carvedilol and ivabradine reduced the heart rate by 33%, 27%, and 55%, respectively, compared to controls (6%). In ED8 embryos this effect was more pronounced with a heart rate reduction by 71%, 54%, 53%, respectively (controls 36%). Cardiac output decreased in all tested groups but only proved significant in the metoprolol group in ED8 embryos. The number of -adrenergic receptors showed a downward tendency during embryonic development but a negative chronotropic effect of tested drugs was increasingly pronounced with embryonic maturity. This effect was associated with reduced cardiac output in chick embryos, probably leading to premature death....