220 resultados para Lucan, 39-65.


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Artificial insemination is routinely used in the swine industry to reduce the costs of production through to increase the efficiency of the refrigerated boar semen process. The objective of this study was to evaluate the effect of different levels of cysteine (CYS) added to the Beltsville Thawing Solution (BTS) extender semen during cooling for up to 72 hours. Ejaculated from three boars were collected with the gloved-hand technique and semen aliquots were diluted in BTS as follow: BTS only (BTS), BTS + 0.1mM cysteine (CYS0.1), BTS + 0.5mM cysteine (CYS0.5), BTS + 1.0mM cysteine (CYS1.0), BTS + 2.5mM cysteine (CYS2.5), BTS + 5.0mM cysteine (CYS5.0), BTS + 10.0mM cysteine (CYS10.0), and BTS + 20.0mM cysteine (CYS20.0). Evaluation of sperm integrity were analyzed using 0.5mg/ml propidium iodide (plasma membrane), 100µg/ml isothiocynate-conjugated Pisum sativun agglutinin (acrosomal membrane) and 153µM 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl carbocyanine iodide (mitochondria potential) after semen dilution at specific times (0, 24, 48 and 72 hours). Additionally, we also evaluated the effects of 5.0 mM CYS addition in the BTS extender on the maintenance of sperm quality and their influence on fertility in the swine production. After artificial insemination, animals were evaluated based on the estrous return and the number of piglet's born. Cysteine at concentrations of 10.0 and 20.0mM resulted in more pronounced reductions even at the time zero. Semen viability decreased to levels below 10% at these high levels of CYS in the first 24 hour of storage at 17ºC. At the end of the storage time, less than 65% of sperm cells had intact plasma membrane in all groups. The sperm viability decreased significantly when the semen was added at high concentrations of CYS (time "0"; CYS10.0 and CYS20.0; p<0.05), when compared to the other CYS concentrations. The BTS (10.20±0.39) treated group showed a lower rate of estrus return when compared to other (BTSCYS; 86.05±039), and it showed also the highest total number of piglets borne per treatment (12.71±3.38 vs. 9.00±3.38, respectively). In conclusion, the addition of CYS in the BTS semen extender did not maintain spermatic viability of boar cooled spermatozoa and it results in a higher percentage of return to estrus and lower number of piglets borne.

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Mediante o teste de ELISA foi determinada a presença de anticorpos para Mycobacterium avium subsp. paratuberculosis (map) em amostras de soro de 734 caprinos e 392 ovinos, sem sinais clìnicos aparentes, provenientes de 14 Municipios do semiárido Paraibano. Em caprinos, a frequência média de anticorpos de 44,86± 22,91% e em ovinos foi de 52,96±31,49. Das 46 propriedades estudadas, 44 (95,65%) apresentaram pelo menos um animal soropositivo. Nos 14 municípios avaliados houve presença de animais sorologicamente positivos, variando de 20% a 70%. Em caprinos sem raça definida e mestiços a frequência (48,56%) foi significativamente inferior (P<0,0270) que a de caprinos de raças puras (57,24%). Em ovinos com escore de 1 a 3 a frequência (59,39%) foi significativamente maior (P=0,0034) que a frequência em ovinos com escore superior a 3 (42,42%). Não houve diferença significativa nas frequências em caprinos e ovinos de diferentes idades, em caprinos com diferente escore corporal e em ovinos de diferentes raças. No exame microbiológico, em cultivos em meio HEYM com micobactina J, foram observadas colônias semelhantes às do Map em 9 (6,58%) das 180 amostras de fezes, sendo uma de caprinos e 8 de ovinos. Na coloração de Ziehl Nieelsen as bactérias apresentavam características morfo-tintorias de Map. Os resultados obtidos indicam alta frequência de caprinos e ovinos infectados com Map no semiárido da Paraíba, tornando-se necessário desenvolver pesquisas sobre a epidemiologia e forma de controle da doença nas condições de criação da região.

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Este trabalho teve como objetivos determinar a prevalência de propriedades de caprinos leiteiros positivas e de animais soropositivos para leptospirose no semiárido paraibano. A amostragem foi delineada para a determinação da prevalência de propriedades positivas (focos) e de animais soropositivos para a infecção por Leptospira spp. No total, foram colhidas amostras de sangue de 975 animais procedentes de 110 propriedades leiteiras localizadas no Munícipio de Monteiro, microrregião do Cariri Ocidental, Estado da Paraíba. Para o diagnóstico da infecção por Leptospira spp., foi utilizado o teste de soroaglutinação microscópica (SAM), utilizando como antígenos 24 sorovares. Uma propriedade foi considerada foco quando apresentou pelo menos um animal soropositivo. As prevalências de propriedades positivas e de animais soropositivos foram de 43,6% (IC 95% = 34,2-53,4%) e de 8,7% (IC 95% = 5,7-12,9%), respectivamente. Nos animais, os sorovares mais frequentes foram Autumnalis (1,74%; IC 95% = 0,97-3,09%), Sentot (1,71%; IC 95% = 0,82-3,52%) e Whitcomb (1,39%; IC 95% = 0,65-2,93%), e nas propriedades, os sorovares Autumnalis (10,9%; IC 95% = 5,8-18,3%), Whitcomb (8,2%; IC 95% = 3,8-15,0%) e Sentot e Patoc (7,3%; IC 95% = 3,2-13,8%) foram os mais frequentes. Sugere-se que a infecção está distribuída em caprinos da região, e que há necessidade de implantação de medidas de controle e prevenção, com o intuito de reduzir a ocorrência da infecção e, consequentemente, diminuir perdas econômicas ocasionadas e bloquear a possível transmissão do agente aos seres humanos.

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A mastite em ovelhas da raça Santa Inês apresenta-se como um problema de grande proporção e gravidade e é dificilmente tratada com sucesso. O objetivo deste estudo foi caracterizar aspectos clínicos, epidemiológicos e etiológicos da mastite clínica em ovelhas de corte criadas no norte do Paraná. O presente estudo foi realizado entre os meses de outubro de 2009 a setembro de 2010 envolvendo 54 rebanhos de ovinos de corte de diferentes raças. Durante as visitas às propriedades, um questionário foi preenchido com a finalidade de caracterizar o problema. Setenta ovelhas com mastite clínica foram examinadas e amostras de secreção láctea foram colhidas para exame microbiológico. A mastite foi considerada um problema relevante em 39 propriedades (72,3%), com frequência média de 6,74%. Casos crônicos e agudos de mastite foram observados em 69% e 31% das ovelhas examinadas, respectivamente. Em ambos os casos, a mastite flegmonosa foi a forma mais encontrada (65,5% dos casos). O agente etiológico mais prevalente foi Staphylococcus coagulase negativo (54,5%), seguido por S. aureus e A. pyogenes (11,5% cada). Mannheimia haemolytica foi isolada em dois casos. Sistema de criação não extensivo e raça Santa Inês foram identificados como fatores de risco para o desenvolvimento de mastite clínica. Secagem das fêmeas após 120 dias de lactação e separação de fêmeas doentes do rebanho foram associadas com menor ocorrência da doença. Recomenda-se a limpeza adequada das instalações e a secagem mais tardia, principalmente em rebanhos Santa Inês.

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A tolerância da gramínea forrageira capim-elefante a herbicidas aplicados isoladamente ou em misturas entre si, aplicados em condições de pré e pós-emergência da forrageira, bem como a eficiência desses produtos no controle de B. decumbens e outras espécies de plantas daninhas, foram avaliadas em dois experimentos. Os herbicidas aplicados no experimento conduzido em condições de pré-emergência do capim-elefante, com as respectivas doses em kg ha-1, foram: metolachlor (1,152; 2,304; e 3,456), oxyfluorfen (0,48; 0,96 e 1,44) e a formulação comercial de atrazine + metolachlor (1,25; 2,50; e 3,75), três repetições. Os herbicidas aplicados no experimento instalado em condições de pós-emergência da forrageira, com as respectivas doses em kg ha-1,foram: ametryne (1,25; 2,50; e 3,75) e oxyfluorfen (0,48; 0,96; e 1,44), com quatro repetições. Os tratamentos foram distribuídos em blocos ao acaso; sendo que, em ambos os experimentos foram adicionadas as testemunhas (capinada e sem capina), e os cultivares de capim-elefante utilizados em ambos os experimentos foram Cameroon e Pioneiro. A aplicação dos herbicidas em pré-emergência da forrageira foi feita um dia após o plantio com solo úmido; no experimento em pós-emergência do capim-elefante os herbicidas foram aplicados sobre o topo das plantas da cultura forrageira, aos 20 dias após a emergência. Metolachlor e atrazine + metolachlor, em pré-emergência, foram seletivos para os dois cultivares testados. O oxyfluorfen, até 0,96 kg ha-1, foi seletivo para a cultura forrageira nas aplicações tanto em pré- como em pós-emergência. O ametryne, em pós-emergência, também foi seletivo aos cultivares na dose inferior a 2,50 kg ha-1. B. decumbens e B. brizantha foram eficientemente controladas (90,9%) em pré-emergência, exceto na menor dose de metolachlor e atrazine + metolachlor. O controle das dicotiledôneas atingiu 85% com metolachlor, atrazine + metolachlor e oxyfluorfen, exceto nas menores doses dos produtos. Em pós-emergência, o ametryne, nas doses de 2,50 e 3,75 kg ha¹, e o oxyfluorfen, nas três doses estudadas, proporcionaram controle superior a 90,3% para B. decumbens, B. brizantha, S. glaziovii e S. urens; todavia, o oxyfluorfen propiciou controle de A. australe e de D. tortuosum inferior a 81,0%, e o ametryne, inferior a 75,6% para D. tortuosum. Tanto na aplicação em pré quanto em pós-emergência, o efeito residual de controle estendeu-se até os 90 dias após aplicação dos herbicidas. O capim-elefante tratado com herbicidas aplicados em pré-emergência cresceu mais (36,28 a 42,79%); em pós-emergência esse crescimento foi menor (34,78 a 47,1%) para o cultivar Pioneiro, quando comparado com a testemunha sem capina. Para o cultivar Cameroon o crescimento foi de 39,90 a 51,30% quando o herbicida foi aplicado em pré-emergência e de 39,83 a 46,61% em pós-emergência. O acúmulo de biomassa seca da parte aérea do cultivar Pioneiro foi maior em pré-emergência (33,22 a 48,85%) e em pós-emergência (73,80 a 76,65%); para o cultivar Cameroon esse acúmulo foi de 79,63 a 83,95% em pré-emergência e de 61,92 a 68,21% em pós-emergência, também em relação à testemunha sem capina. O cultivar Pioneiro mostrou ser mais tolerante à interferência das plantas daninhas que o Cameroon.

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Data of corn ear production (kg/ha) of 196 half-sib progenies (HSP) of the maize population CMS-39 obtained from experiments carried out in four environments were used to adapt and assess the BLP method (best linear predictor) in comparison with to the selection among and within half-sib progenies (SAWHSP). The 196 HSP of the CMS-39 population developed by the National Center for Maize and Sorghum Research (CNPMS-EMBRAPA) were related through their pedigree with the recombined progenies of the previous selection cycle. The two methodologies used for the selection of the twenty best half-sib progenies, BLP and SAWHSP, led to similar expected genetic gains. There was a tendency in the BLP methodology to select a greater number of related progenies because of the previous generation (pedigree) than the other method. This implies that greater care with the effective size of the population must be taken with this method. The SAWHSP methodology was efficient in isolating the additive genetic variance component from the phenotypic component. The pedigree system, although unnecessary for the routine use of the SAWHSP methodology, allowed the prediction of an increase in the inbreeding of the population in the long term SAWHSP selection when recombination is simultaneous to creation of new progenies.

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The present paper reviews work from our laboratories evaluating the importance of adrenal cortical hormones in acidification by proximal and cortical distal tubules. Proximal acidification was determined by stationary microperfusion, and measurement of bicarbonate reabsorption using luminal pH determination was performed with H+-ion-sensitive microelectrodes. Rats were adrenalectomized (ADX) 48 h before the experiments, and corticosteroids (aldosterone (A), corticosterone (B), and 18-OH corticosterone (18-OH-B)) were injected intramuscularly 100 and 40 min before the experiments. In ADX rats stationary pH increased significantly to 7.03 as compared to sham-operated rats (6.78). Bicarbonate reabsorption decreased from 2.65 &plusmn; 0.18 in sham-operated rats to 0.50 &plusmn; 0.07 nmol cm-2 s-1 after ADX. The administration of the three hormones stimulated proximal tubule acidification, reaching, however, only 47.2% of the sham values in aldosterone-treated rats. Distal nephron acidification was studied by measuring urine minus blood pCO2 differences (U-B pCO2) in bicarbonate-loaded rats treated as above. This pCO2 difference is used as a measure of the distal nephron ability to secrete H+ ions into an alkaline urine. U-B pCO2 decreased significantly from 39.9 &plusmn; 1.26 to 11.9 &plusmn; 1.99 mmHg in ADX rats. When corticosteroids were given to ADX rats before the experiment, U-B pCO2 increased significantly, but reached control levels only when aldosterone (two 3-&micro;g doses per rat) plus corticosterone (220 &micro;g) were given together. In order to control for the effect of aldosterone on distal transepithelial potential difference one group of rats was treated with amiloride, which blocks distal sodium channels. Amiloride-treated rats still showed a significant reduction in U-B pCO2 after ADX. Only corticosterone and 18-OH-B but not aldosterone increased U-B pCO2 back to the levels of sham-operated rats. These results show that corticosteroids stimulate renal tubule acidification both in proximal and distal nephrons and provide some clues about the mechanism of action of these steroids

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In the present study we evaluated the nature of angiotensin receptors involved in the antidiuretic effect of angiotensin-(1-7) (Ang-(1-7)) in water-loaded rats. Water diuresis was induced in male Wistar rats weighing 280 to 320 g by water load (5 ml/100 g body weight by gavage). Immediately after water load the rats were treated subcutaneously with (doses are per 100 g body weight): 1) vehicle (0.05 ml 0.9% NaCl); 2) graded doses of 20, 40 or 80 pmol Ang-(1-7); 3) 200 nmol Losartan; 4) 200 nmol Losartan combined with 40 pmol Ang-(1-7); 5) 1.1 or 4.4 nmol A-779; 6) 1.1 nmol A-779 combined with graded doses of 20, 40 or 80 pmol Ang-(1-7); 7) 4.4 nmol A-779 combined with graded doses of 20, 40 or 80 pmol Ang-(1-7); 8) 95 nmol CGP 42112A, or 9) 95 nmol CGP 42112A combined with 40 pmol Ang-(1-7). The antidiuretic effect of Ang-(1-7) was associated with an increase in urinary Na+ concentration, an increase in urinary osmolality and a reduction in creatinine clearance (CCr: 0.65 ± 0.04 ml/min vs 1.45 ± 0.18 ml/min in vehicle-treated rats, P<0.05). A-779 and Losartan completely blocked the effect of Ang-(1-7) on water diuresis (2.93 ± 0.34 ml/60 min and 3.39 ± 0.58 ml/60 min, respectively). CGP 42112A, at the dose used, did not modify the antidiuretic effect of Ang-(1-7). The blockade produced by Losartan was associated with an increase in CCr and with an increase in sodium and water excretion as compared with Ang-(1-7)-treated rats. When Ang-(1-7) was combined with A-779 there was an increase in CCr and natriuresis and a reduction in urine osmolality compared with rats treated with Ang-(1-7) alone. The observation that both A-779, which does not bind to AT1 receptors, and Losartan blocked the effect of Ang-(1-7) suggests that the kidney effects of Ang-(1-7) are mediated by a non-AT1 angiotensin receptor that is recognized by Losartan.

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The widespread consumption of anorectics and combined anorectic + alcohol misuse are problems in Brazil. In order to better understand the interactive effects of ethanol (EtOH) and diethylpropion (DEP) we examined the locomotion-activating effects of these drugs given alone or in combination in mice. We also determined whether this response was affected by dopamine (DA) or opioid receptor antagonists. A total of 160 male Swiss mice weighing approximately 30 g were divided into groups of 8 animals per group. The animals were treated daily for 7 consecutive days with combined EtOH + DEP (1.2 g/kg and 5.0 mg/kg, ip), EtOH (1.2 g/kg, ip), DEP (5.0 mg/kg, ip) or the control solution coadministered with the DA antagonist haloperidol (HAL, 0.075 mg/kg, ip), the opioid antagonist naloxone (NAL, 1.0 mg/kg, ip), or vehicle. On days 1, 7 and 10 after the injections, mice were assessed in activity cages at different times (15, 30, 45 and 60 min) for 5 min. The acute combination of EtOH plus DEP induced a significantly higher increase in locomotor activity (day 1: 369.5 ± 34.41) when compared to either drug alone (day 1: EtOH = 232.5 ± 23.79 and DEP = 276.0 ± 12.85) and to control solution (day 1: 153.12 ± 7.64). However, the repeated administration of EtOH (day 7: 314.63 ± 26.79 and day 10: 257.62 ± 29.91) or DEP (day 7: 309.5 ± 31.65 and day 10: 321.12 ± 39.24) alone or in combination (day 7: 459.75 ± 41.28 and day 10: 427.87 ± 33.0) failed to induce a progressive increase in the locomotor response. These data demonstrate greater locomotion-activating effects of the EtOH + DEP combination, probably involving DA and/or opioid receptor stimulation, since the daily pretreatment with HAL (day 1: EtOH + DEP = 395.62 ± 11.92 and EtOH + DEP + HAL = 371.5 ± 6.76; day 7: EtOH + DEP = 502.5 ± 42.27 and EtOH + DEP + HAL = 281.12 ± 16.08; day 10: EtOH + DEP = 445.75 ± 16.64 and EtOH + DEP + HAL = 376.75 ± 16.4) and NAL (day 1: EtOH + DEP = 553.62 ± 38.15 and EtOH + DEP + NAL = 445.12 ± 55.67; day 7: EtOH + DEP = 617.5 ± 38.89 and EtOH + DEP + NAL = 418.25 ± 61.18; day 10: EtOH + DEP = 541.37 ± 32.86 and EtOH + DEP + NAL = 427.12 ± 51.6) reduced the locomotor response induced by combined administration of EtOH + DEP. These findings also suggest that a major determinant of combined anorectic-alcohol misuse may be the increased stimulating effects produced by the combination.

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The molluscicidal activity of Punica granatum Linn. (Punicaceae) and Canna indica Linn. (Cannaceae) against the snail Lymnaea acuminata was studied. The molluscicidal activity of P. granatum bark and C. indica root was found to be both time and dose dependent. The toxicity of P. granatum bark was more pronounced than that of C. indica. The 24 h LC50 of the column-purified root of C. indica was 6.54 mg/l whereas that of the column-purified bark of P. granatum was 4.39 mg/l. The ethanol extract of P. granatum (24 h LC50: 22.42 mg/l) was more effective than the ethanol extract of C. indica (24 h LC50: 55.65 mg/l) in killing the test animals. P. granatum and C. indica may be used as potent molluscicides since the concentrations used to kill the snails were not toxic for the fish Colisa fasciatus, which shares the same habitat with the snail L. acuminata.

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Trials have demonstrated that high-dose escalation followed by autologous transplantation can promote better long-term survival as salvage treatment in malignant lymphomas. The aim of the present nonrandomized clinical trial was to demonstrate the role of high-dose cyclophosphamide (HDCY) in reducing tumor burden and also to determine the effectiveness of HDCY followed by etoposide (VP-16) and methotrexate (MTX) in Hodgkin's disease plus high-dose therapy with peripheral blood progenitor cell (PBPC) transplantation as salvage treatment. From 1998 to 2000, 33 patients with a median age of 33 years (13-65) affected by aggressive non-Hodgkin's lymphoma (NHL) (60.6%) or persistent or relapsed Hodgkin's disease (39.4%) were enrolled and treated using high dose escalation (HDCY + HDVP-16 plus HDMTX in Hodgkin's disease) followed by autologous PBPC transplantation. On an "intention to treat" basis, 33 patients with malignant lymphomas were evaluated. The overall median follow-up was 400 days (40-1233). Thirty-one patients underwent autografting and received a median of 6.19 x 10(6)/kg (1.07-29.3) CD34+ cells. Patients who were chemosensitive to HDCY (N = 22) and patients who were chemoresistant (N = 11) presented an overall survival of 96 and 15%, respectively (P<0.0001). Overall survival was 92% for chemosensitive patients and 0% for patients who were still chemoresistant before transplantation (P<0.0001). Toxicity-related mortality was 12% (four patients), related to HDCY in two cases and to transplant in the other two. HDCY + HDVP-16 plus HDMTX in only Hodgkin's disease followed by autologous PBPC proved to be effective and safe as salvage treatment for chemosensitive patients affected by aggressive NHL and Hodgkin's disease, with acceptable mortality rates related to sequential treatment.

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We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients <=12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases > or = 3 months; median 3 ± 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children <3 months of age, whose acute-phase PBMC were mostly T lymphocytes (63.0 ± 9.0%). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 ± 17.7%). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV.

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There are few population-based studies of renal dysfunction and none conducted in developing countries. In the present study the prevalence and predictors of elevated serum creatinine levels (SCr > or = 1.3 mg/dl for men and 1.1 mg/dl for women) were determined among Brazilian adults (18-59 years) and older adults (>60 years). Participants included all older adults (N = 1742) and a probabilistic sample of adults (N = 818) from Bambuí town, MG, Southeast Brazil. Predictors were investigated using multiple logistic regression. Mean SCr levels were 0.77 ± 0.15 mg/dl for adults, 1.02 ± 0.39 mg/dl for older men, and 0.81 ± 0.17 mg/dl for older women. Because there were only 4 cases (0.48%) with elevated SCr levels among adults, the analysis of elevated SCr levels was restricted to older adults. The overall prevalence of elevated SCr levels among the elderly was 5.09% (76/1494). The prevalence of hypercreatinemia increased significantly with age (chi² = 26.17, P = 0.000), being higher for older men (8.19%) than for older women (5.29%, chi² = 5.00, P = 0.02). Elevated SCr levels were associated with age 70-79 years (odds ratio [OR] = 2.25, 95% confidence interval [CI]: 1.15-4.42), hypertension (OR = 3.04, 95% CI: 1.34-6.92), use of antihypertensive drugs (OR = 2.46, 95% CI: 1.26-4.82), chest pain (OR = 3.37, 95% CI: 1.31-8.74), and claudication (OR = 3.43, 95% CI: 1.30-9.09) among men, and with age >80 years (OR = 4.88, 95% CI: 2.24-10.65), use of antihypertensive drugs (OR = 4.06, 95% CI: 1.67-9.86), physical inactivity (OR = 2.11, 95% CI: 1.11-4.02) and myocardial infarction (OR = 3.89, 95% CI: 1.58-9.62) among women. The prevalence of renal dysfunction observed was much lower than that reported in other population-based studies, but predictors were similar. New investigations are needed to confirm the variability in prevalence and associated factors of renal dysfunction among populations.

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Hormone replacement therapy (HRT) reduces cardiovascular risks, although the initiation of therapy may be associated with transient adverse ischemic and thrombotic events. Antibodies against heat shock protein (Hsp) and oxidized low density lipoprotein (LDL) have been found in atherosclerotic lesions and plasma of patients with coronary artery disease and may play an important role in the pathogenesis of atherosclerosis. The aim of the present study was to assess the effects of HRT on the immune response by measuring plasma levels of antibodies against Hsp 65 and LDL with a low and high degree of copper-mediated oxidative modification of 20 postmenopausal women before and 90 days after receiving orally 0.625 mg equine conjugate estrogen plus 2.5 mg medroxyprogesterone acetate per day. HRT significantly increased antibodies against Hsp 65 (0.316 ± 0.03 vs 0.558 ± 0.11) and against LDL with a low degree of oxidative modification (0.100 ± 0.01 vs 0.217 ± 0.02) (P<0.05 and P<0.001, respectively, ANOVA). The hormone-mediated immune response may trigger an inflammatory response within the vessel wall and potentially increase plaque burden. Whether or not this immune response is temporary or sustained and deleterious requires further investigation.

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The genetic basis for dementias is complex. A common polymorphism in the apolipoprotein E (APOE) gene is considered to be the major risk factor in families with sporadic and late-onset Alzheimer's disease as well as in the general population. The distribution of alleles and genotypes of the APOE gene in late-onset Alzheimer's disease (N = 68), other late-life dementias (N = 39), and in cognitively normal controls (N = 58) was determined, as also was the risk for Alzheimer's disease associated with the epsilon4 allele. Peripheral blood samples were obtained from a total of 165 individuals living in Brazil aged 65-82 years. Genomic DNA was amplified by the polymerase chain reaction and the products were digested with HhaI restriction enzyme. APOE epsilon2 frequency was considerably lower in the Alzheimer's disease group (1%), and the epsilon3 allele and epsilon3/epsilon3 genotype frequencies were higher in the controls (84 and 72%, respectively) as were the epsilon4 allele and epsilon3/epsilon4 genotype frequencies in Alzheimer's disease (25 and 41%, respectively). The higher frequency of the epsilon4 allele in Alzheimer's disease confirmed its role as a risk factor, while epsilon2 provided a weak protection against development of the disease. However, in view of the unexpectedly low frequency of the epsilon4 allele, additional analyses in a more varied Brazilian sample are needed to clarify the real contribution of apolipoprotein E to the development of Alzheimer's disease in this population.