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Lamb KE, Ball K, Andrianopoulos N, Costa C, Cutumisu N, Ellaway A, Kamphuis C, Mentz G, Pearce J, Santana P, Schulz AJ, Spence J, Thornton LE, van Lenthe F, Zenk S. Associations between Neighbourhood Disadvantage and Fruit and Vegetable Consumption in Seven Countries. Int J Epidemiol 2015. [DOI: 10.1093/ije/dyv096.136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Baleia J, Santana P, Barata J. On Exploiting Haptic Cues for Self-Supervised Learning of Depth-Based Robot Navigation Affordances. J INTELL ROBOT SYST 2015. [DOI: 10.1007/s10846-015-0184-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gomes P, Santana P, Barata J. A Vision-Based Approach to Fire Detection. INT J ADV ROBOT SYST 2014. [DOI: 10.5772/58821] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This paper presents a vision-based method for fire detection from fixed surveillance smart cameras. The method integrates several well-known techniques properly adapted to cope with the challenges related to the actual deployment of the vision system. Concretely, background subtraction is performed with a context-based learning mechanism so as to attain higher accuracy and robustness. The computational cost of a frequency analysis of potential fire regions is reduced by means of focusing its operation with an attentive mechanism. For fast discrimination between fire regions and fire-coloured moving objects, a new colour-based model of fire's appearance and a new wavelet-based model of fire's frequency signature are proposed. To reduce the false alarm rate due to the presence of fire-coloured moving objects, the category and behaviour of each moving object is taken into account in the decision-making. To estimate the expected object's size in the image plane and to generate geo-referenced alarms, the camera-world mapping is approximated with a GPS-based calibration process. Experimental results demonstrate the ability of the proposed method to detect fires with an average success rate of 93.1% at a processing rate of 10 Hz, which is often sufficient for real-life applications.
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Santana P, Mendonça R, Correia L, Barata J. Neural-swarm visual saliency for path following. Appl Soft Comput 2013. [DOI: 10.1016/j.asoc.2012.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Santana P, Correia L, Mendonça R, Alves N, Barata J. Tracking natural trails with swarm-based visual saliency. J FIELD ROBOT 2012. [DOI: 10.1002/rob.21423] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Couceiro L, Santana P, Nunes C. Pulmonary tuberculosis and risk factors in Portugal: a spatial analysis. Int J Tuberc Lung Dis 2011; 15:1445-54, i. [DOI: 10.5588/ijtld.10.0302] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Vasconcelos J, Freire E, Morais J, Machado J, Santana P. The health impacts of poor housing conditions and thermal discomfort. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.proenv.2011.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Santana P, Guedes M, Correia L, Barata J. Stereo-based all-terrain obstacle detection using visual saliency. J FIELD ROBOT 2010. [DOI: 10.1002/rob.20376] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Duhot D, Durel A, Santana P, Hebbrecht G. Les angines sont-elles en réalité si largement surtraitées par les antibiotiques ? Étude à partir des données de l’Observatoire de la médecine générale en 2007. Rev Epidemiol Sante Publique 2009. [DOI: 10.1016/j.respe.2009.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Williamson LM, Rosato M, Teyhan A, Santana P, Harding S. AIDS mortality in African migrants living in Portugal: evidence of large social inequalities. Sex Transm Infect 2009; 85:427-31. [PMID: 19525262 PMCID: PMC3786509 DOI: 10.1136/sti.2008.034066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To examine infectious disease and AIDS mortality among African migrants in Portugal, gender and socio-economic differences in AIDS mortality risk, and differences between African migrants to Portugal and to England and Wales. METHODS Data from death registrations, 1998-2002, and the 2001 Census were used to derive standardised death rates by country of birth, occupational class (men only), and marital status. RESULTS Compared with people born in Portugal, African migrants had higher mortality for infectious diseases including AIDS. There was considerable heterogeneity among Africans, with those from Cape Verde having the highest mortality. Death rates were more than five times higher among those who were unmarried than those who were. A larger proportion of Africans were unmarried accounting for some excess mortality. Death rates were also higher among men from manual occupational classes than among men from non-manual. A comparison with England and Wales shows that death rates for infectious disease and AIDS in Portugal are much higher and Africans in Portugal also fare worse than Africans in England and Wales. CONCLUSION AIDS mortality rates were higher among Africans than those born in Portugal and were associated with socio-environmental factors. Further research is required to interpret the excess mortality among Africans and there is a need to ensure the inclusion of relevant data items on ethnicity in national monitoring and surveillance systems.
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Aubert JP, Catrice M, Di Pumpo A, Gervais A, Santana P, Majerholc C, Marcellin P. U-07 PREVAC B : Prévention de l’infection par le VHB parmi les populations migrantes. Med Mal Infect 2009. [DOI: 10.1016/s0399-077x(09)74313-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Aubert J, Santana P, Di Pumpo A, Gervais A, Majerholc C, Marcellin P. COL4-03 Stratégies préventives de l’hépatite B au sein des populations migrantes. Med Mal Infect 2008. [DOI: 10.1016/s0399-077x(08)73028-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Schaap MM, Kunst AE, Leinsalu M, Regidor E, Ekholm O, Dzurova D, Helmert U, Klumbiene J, Santana P, Mackenbach JP. Effect of nationwide tobacco control policies on smoking cessation in high and low educated groups in 18 European countries. Tob Control 2008; 17:248-55. [PMID: 18483129 DOI: 10.1136/tc.2007.024265] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Recently a scale was introduced to quantify the implementation of tobacco control policies at country level. Our study used this scale to examine the potential impact of these policies on quit ratios in European countries. Special attention was given to smoking cessation among lower educational groups. METHODS Cross-sectional data were derived from national health surveys from 18 European countries. In the analyses we distinguished between country, sex, two age groups (25-39 and 40-59 years) and educational level. Age-standardised quit ratios were calculated as total former-smokers divided by total ever-smokers. In regression analyses we explored the correlation between national quit ratios and the national score on the Tobacco Control Scale (TCS). RESULTS Quit ratios were especially high (>45%) in Sweden, England, The Netherlands, Belgium and France and relatively low (<30%) in Lithuania and Latvia. Higher educated smokers were more likely to have quit smoking than lower educated smokers in all age-sex groups in all countries. National score on the tobacco control scale was positively associated with quit ratios in all age-sex groups. The association of quit ratios with score on TCS did not show consistent differences between high and low education. Of all tobacco control policies of which the TCS is constructed, price policies showed the strongest association with quit ratios, followed by an advertising ban. CONCLUSION Countries with more developed tobacco control policies have higher quit ratios than countries with less developed tobacco control policies. High and low educated smokers benefit about equally from the nationwide tobacco control policies.
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Gasparetto EL, Leite CDC, Lucato LT, Barros CVD, Marie SKN, Santana P, Aguiar PHPD, Rosemberg S. Intracranial meningiomas: magnetic resonance imaging findings in 78 cases. ARQUIVOS DE NEURO-PSIQUIATRIA 2007; 65:610-4. [PMID: 17876400 DOI: 10.1590/s0004-282x2007000400012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 04/27/2007] [Indexed: 11/22/2022]
Abstract
OBJECTIVE: To present the magnetic resonance (MR) imaging findings of 78 patients with meningiomas diagnosed in a single institution. METHOD: 78 patients with histological proven intracranial meningioma were studied. There were 52 female and 26 male patients (median=56 years). All MR imaging examinations were performed with 1.5-T MR imaging unit with standard protocol. The images were studied by two neuroradiologists, who reached the decisions regarding the findings by consensus. RESULTS: Most of the tumors showed low signal on T1- (60%) and high signl on T2- (68%) and FLAIR (69%) weighted images. Also, the lesions showed heterogeneous signal on T1 (60%), T2 (68%) and FLAIR (64%) sequences. After contrast administration, 83% (n=65) of the tumors presented acentuated and 17% (n=13) showed moderate enhancement. The tumors were located in the frontal lobe in 44% of the cases, in the parietal lobe in 35%, the occipital lobe in 19% and the temporal lobe in 12% of the patients. Areas of vasogenic edema around the tumors were seen in 90% of the cases. Twenty six per cent of the cases showed bone infiltration, and the dural tail sign was seen in 59% of the tumors. CONCLUSION: Intracranial meningiomas usually show heterogeneous low signal on T1- and high signal on T2-weighted and FLAIR images, with intense enhancement after contrast administration. The frontal and parietal lobes are commonly affected. In addition, brain edema, dural tail sign and bone infiltration are the most frequent associated findings.
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Harding S, Boroujerdi M, Santana P, Cruickshank J. Decline in, and lack of difference between, average birth weights among African and Portuguese babies in Portugal. Int J Epidemiol 2005; 35:270-6. [PMID: 16280368 DOI: 10.1093/ije/dyi225] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In preliminary data in Portugal, we found that African babies of migrant mothers were heavier than White Portuguese babies born in Lisbon. We investigate whether this pattern is replicated in the national data, and in addition the trends in birth weight in these groups. METHODS DESIGN AND SETTING Births registered between 1995 and 2002 classified by reported nationality of mothers. PARTICIPANTS 849,595 Portuguese births ('Portuguese' nationality, predominantly of European descent) and 22,463 African births ('Angola', 'Cape Verde', or 'Guinea Bissau, Republic of Guinea or Equatorial Guinea' nationality, predominantly of African origin). RESULTS Among Portuguese births, there was a decline in births to teenaged mothers and an increase to mothers aged >or=35 years, with >9 years of education or in a non-manual class, but among African births there was an increase in births to teenaged mothers and a decline to mothers from advantaged socioeconomic backgrounds. Using the Wilcox-Russell method, overall mean birth weights of term Portuguese (3,303, SD 424 g) and African (3297, SD 441 g) babies were not different but the percentage of small preterm births was higher among African (4.7%) than among Portuguese (2.9%) births. Between 1995 and 2002, mean birth weight of term Portuguese babies declined by 58 g (3,334-3,276 g) and of African babies by 57 g (3,341-3,284 g). The left shift of the birth weight distributions was independent of maternal age, parity, and social factors among Portuguese babies, but among African babies the decrease appeared to be associated with socioeconomic advantage. CONCLUSION There has been a downward trend in birth weights in Portugal among both Portuguese and African term births, but average birth weights of the two groups were similar.
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Morales V, Gonzalez-Robayna I, Hernandez I, Quintana J, Santana P, Ruiz de Galarreta CM, Fanjul LF. The inducible isoform of CREM (inducible cAMP early repressor, ICER) is a repressor of CYP19 rat ovarian promoter. J Endocrinol 2003; 179:417-25. [PMID: 14656211 DOI: 10.1677/joe.0.1790417] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The synthesis of estradiol by the granulosa cells is a prominent event in ovarian physiology and depends on the expression of P450(AROM). FSH induces the expression of P450(AROM) in granulosa cells as a result of the presence in the ovarian promoter of a CRE (cAMP response element)-like sequence (CLS). In rodents, LH downregulates aromatase expression during luteinization by an as yet undescribed mechanism. In granulosa cells, LH increases the expression of the inducible cAMP early repressor (ICER), an isoform of CREM (cAMP-responsive element modulator) that represses cAMP-induced transcription. The possibility that ICER represses the activity of the aromatase ovarian promoter, thus being part of the mechanism underlying the effects of LH was investigated. We have found that: (1) nuclear proteins from forskolin-stimulated granulosa cells were specifically bound to an oligonucleotide containing the CLS sequence of the CYP19 ovarian promoter and one out of the two protein-DNA complexes formed was supershifted by an anti-CREM antibody; (2) in granulosa cells, forskolin-induced increases in P450(AROM) promoter luciferase reporter gene activity were prevented by the transient overexpression of ICER; (3) similar results were obtained in 8-Br-cAMP-stimulated R2C cells, a Leydig tumor cell line routinely used for the study of P450(AROM) promoter activity; (4) both ICER mRNA levels and P450(AROM) promoter-driven luciferase activity were elevated 6 and 12 h after stimulation of R2C cells with 8-Br-cAMP and were decreased 24 and 48 h later; (5) in an R2C polyclonal line overexpressing ICER, the promoter activity at early stages of stimulation was completely attenuated, while 24 and 48 h downregulation was prevented in another R2C line stably transfected with an antisense ICER construct. These results suggest that ICER represses CYP19 ovarian promoter and that LH-induced expression of ICER may serve to downregulate P450(AROM) transcription in granulosa cells during luteinization.
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Gallardo G, Tabraue C, Quintana J, López-Blanco F, Cabrera J, Díaz R, Estévez F, Ruiz de Galarreta CM, Fanjul LF, Santana P. Regulation by ceramide of epidermal growth factor signal transduction and mitogenesis in cell lines overexpressing the growth factor receptor. Cell Mol Biol (Noisy-le-grand) 2000; 46:1305-12. [PMID: 11075960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Ceramide has emerged as a pleiotropic signal mediator of cellular responses including differentiation, proliferation, cell cycle arrest and apoptosis. In the present study we evaluated the effect of cell permeant ceramide analogues on ligand-induced tyrosine phosphorylation of the EGF receptor (EGFR), phospholipase Cy (PLCgamma) activity and cell proliferation. Treatment with N-acetylsphingosine (C2-cer) and N-hexanoylceramide (C6-cer) prevented EGF-induced tyrosine trans-phosphorylation of the receptor in two different cell lines overexpressing the human EGFR (A431 and EGF-T17 cells). In contrast, treatment of A431 and EGFR-T17 cells with C2-cer or C6-cer did not affect the ligand binding capacity of the receptor, an effect that was however observed after TPA-induced activation of PKC. In addition EGF-stimulated PLCgamma activity was transiently decreased in A431 cells treated with C6-cer and only a modest, albeit significant reduction on ligand-induced 3H-InsP3 generation was observed in EGFR-T17 cells pretreated with ceramide. We also examined the effect of C2-cer on serum (A431)- or EGF (EGFR-T 17)-induced cell proliferation. Treatment of EGFR-TI7 cells with C2-cer (0.1-10 microM) did not affect cell viability, but prevented EGF-induced 3H-thymidine incorporation in a dose-dependent manner. In contrast, 3H-thymidine incorporation in serum-stimulated A431 cells decreased only at the higher doses of C2-cer used (1-10 microM), being this effect accompanied by a slight, albeit significant (20-25%), reduction in cell viability.
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Abstract
The health of the Portuguese has improved considerably in the last twenty years. Economic and social transformations that have contributed to the progressive amelioration of problems of feeding, sanitation, hygiene, housing and social conditions in general, as well as health services, have had decisive effect on this phenomenon. The spectacular regression of the indicators related to transmitted diseases, infant, perinatal (more than 50% between 1985 and 1994) and maternal mortality, and the mortality of children 1 to 4 yr old, also reflects this impact. The positive changes that took place in health indicators were reflected in the growth of life expectancy at birth (2.2 yr more for male and 2.3 more for women between 1985 and 1994) in spite of the fact that the difference in life expectancy in relation to EU countries has grown. Improvement in life expectancy, especially in the older age groups, is not normally associated with significant reductions in morbidity. In fact, increased longevity has become more generally associated with chronic illness or other disabilities requiring more medical services and other forms of personal care. This paper reviews some of the evidence for regional differences in the health status of elderly people in Portugal and considers how health services have reacted to these differences. A preliminary study of health status and patterns of utilisation of elderly people was undertaken. After 30 yr of a National Health Service (NHS) in Portugal we may ask why do inequities in health and access to health care of the elderly population persist? Proactive policies to prevent illness and promote health are still relatively underdeveloped in the Portuguese NHS, and the factors that influence health, such as housing, diet and occupational health hazards, remain largely absent from health and welfare policies. Poor accessibility to health services is the most serious barrier consumers have to face in order to get a medical appointment, and this is more relevant to the oldest part of the population. Geographical location of health care facilities unequally affects the ease of access of different groups of consumers and influences utilisation patterns. Examining the distribution of health services resources is an important way to understand the inequities of access to health and to health care.
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Santana P, Balseiro J, Jiménez E, Franjo C, Legido JL, Carballo E, Paz Andrade MI. J SOLUTION CHEM 2000; 29:1115-1122. [DOI: 10.1023/a:1005191000267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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De Castro-e-Silva E, Luz CP, Marinho CA, Castro L, Sarmento C, Gonzalez V, Oliveira P, Nascimento T, Santana P, Lima AK, Fregoneze JB. Central administration of zinc increases renal sodium and potassium excretion in rats. Brain Res 1999; 845:176-84. [PMID: 10536196 DOI: 10.1016/s0006-8993(99)01930-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of the present study was to investigate the effect of acute third ventricle injections of zinc on the brain control of renal sodium and potassium excretion. Adult Wistar male rats received third ventricle injections of zinc acetate in three different doses (0.03, 0.3 and 3.0 nmol/rat). Third ventricle administration of zinc acetate provoked a significant intensification of natriuresis and kaliuresis as compared to sodium acetate-treated controls. When rats were pretreated with losartan, a selective angiotensin II AT1 receptor antagonist (10.8 nmol/rat into the third ventricle 10 min before central zinc injection) the increase in both natriuresis and kaliuresis was abolished. Furthermore, pretreatment with gadolinium, a calcium channel blocker (0.3 nmol/rat into the third ventricle 20 min before central zinc injection), also blunted the increase in renal sodium and potassium excretion seen in animals receiving zinc alone. In a group of rats receiving the same water load used in the previous experiments, the injection of zinc acetate into the third ventricle (3.0 nmol/rat) did not modify arterial blood pressure. It is suggested that zinc in the central nervous system may be involved in the control of renal sodium and potassium excretion by a mechanism unrelated to blood pressure increase. It is also shown that both natriuretic and kaliuretic actions of zinc depend on AT1 receptor activation. Whatever should be the mechanism(s) related to the central effects of zinc here evidenced, the functional integrity of calcium channels is required.
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Santana P, Fanjul LF, Ruiz de Galarreta CM. Measurement of sphingomyelin and ceramide cellular levels after sphingomyelinase-mediated sphingomyelin hydrolysis. Methods Mol Biol 1999; 105:217-21. [PMID: 10427565 DOI: 10.1385/0-89603-491-7:217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Fregoneze JB, Luz CP, Sarmento C, Gonzalez V, Oliveira P, Santana P, Marinho CA, Castro L, Nascimento T, De Paula S, Lima AK, De Oliveira IR, De Castro-e-Silva E. Central lead administration induces natriuretic and kaliuretic effects in rats. Physiol Behav 1998; 65:321-6. [PMID: 9855482 DOI: 10.1016/s0031-9384(98)00172-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of the present experiments was to discern whether central acute lead injections affect brain control of renal function. Adult Wistar male rats received third-ventricle injections of lead acetate in three different doses (0.03, 0.3, and 3.0 nmol/rat). Lead acetate induced a significant increase in renal excretion of sodium and potassium. Pretreatment with losartan, a selective angiotensin II AT1 receptor antagonist (10.8 nmol/rat into the third ventricle 10 min before central lead injection), inhibits lead-induced natriuretic and kaliuretic effects. In addition, pretreatment with gadolinium, a calcium-channel blocker (0.3 nmol/rat into the third ventricle 20 min before central lead administration), reversed the increase in renal excretion of sodium and potassium provoked by central lead administration. Taken together, the data presented here suggest that lead injected into the third ventricle increases renal excretion of sodium and potassium by a mechanism that depends on the functional integrity of central angiotensin II AT1 receptors and calcium channels.
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González Reyes J, Santana P, González Robaina I, Cabrera Oliva J, Estévez F, Hernández I, López Blanco F, Quintana Aguiar J, Fanjul LF, Ruiz de Galarreta CM. Effect of the protein phosphatase inhibitor okadaic acid on FSH-induced granulosa cell steroidogenesis. J Endocrinol 1997; 152:131-9. [PMID: 9014848 DOI: 10.1677/joe.0.1520131] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To address a possible role of type 1 and 2A serine/threonine protein phosphatases (PP1 and PP2A) in regulating granulosa cell hormonal responses, we investigated the effects of okadaic acid (OA) on FSH- and cAMP-induced steroidogenesis in these cells. When added alone (0.01-1 nmol/l), the cell-permeant phosphatase inhibitor did not affect progesterone and 3 beta-hydroxysteroid dehydrogenase/delta 5-4 isomerase (3 beta-HSD) enzyme activity, whereas when added with FSH it dose-dependently augmented (minimal effective dose, 0.1 nmol/l) gonadotropin-stimulated steroidogenesis in cultured granulosa cells. A similar stimulatory effect of the toxin was observed in cells cultured for 48 h with the cell-permeant analogue dibutyryl cAMP (1 mmol/l), or when granulosa cells were stimulated with the cAMP-inducing agents cholera toxin (1 microgram/ml), forskolin (15 mumol/l) or 1-methyl-3-isobutyl-xanthine (0.1 mmol/l). The observed effect of OA on FSH-supported granulosa cell steroidogenesis was not a consequence of increased cAMP generation, and time course experiments also revealed that a minimal time period of 12 h was necessary for OA (0.1 and 1 nmol/l) to significantly enhance FSH-induced progesterone and 3 beta-HSD enzyme activity. Since OA also inhibits the dephosphorylation of protein kinase C (PKC) substrates, we also compared the effect of OA and the PKC activator 12-O-tetradecanoylphorbol-13-acetate (TPA) on FSH-induced granulosa cell steroidogenic activity. While activation of the PKC pathway with the tumor promoter TPA (10 nmol/l) inhibited progesterone and cAMP accumulation in FSH-stimulated granulosa cells, treatment with OA augmented steroidogenesis and did not affect gonadotropin-induced cAMP generation. Collectively these results suggest that PP1 and PP2A may be important in regulating the phosphorylation state of proteins implicated in the cAMP-protein kinase A-stimulated steroidogenic activity of these cells.
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Orós J, Rodríguez JL, Herráez P, Santana P, Fernández A. Respiratory and digestive lesions caused by Salmonella arizonae in two snakes. J Comp Pathol 1996; 115:185-9. [PMID: 8910746 DOI: 10.1016/s0021-9975(96)80040-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cases of diphtheritic necrotizing gastritis in a Rosy Boa (Lichanura trivirgata) and of necrotizing tracheitis in a double-headed Kingsnake (Lampropeltis hondurensis), both associated with Salmonella arizonae, are described. An immunoperoxidase technique indicated that S. arizonae played a role in the causation of the lesions. In addition, the study showed the value of the technique for the detection of S. arizonae in the tissues of infected snakes.
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