Fetal development of regulatory mechanisms for body fluid homeostasis

The balance of body fluids is critical to health and the development of diseases. Although quite a few review papers have shown that several mechanisms, including hormonal and behavioral regulation, play an important role in body fluid homeostasis in adults, there is limited information on the development of regulatory mechanisms for fetal body fluid balance. Hormonal, renal, and behavioral control of body fluids function to some extent in utero. Hormonal mechanisms including the renin-angiotensin system, aldosterone, and vasopressin are involved in modifying fetal renal excretion, reabsorption of sodium and water, and regulation of vascular volume. In utero behavioral changes, such as fetal swallowing, have been suggested to be early functional development in response to dipsogens. Since diseases, such as hypertension, can be traced to fetal origin, it is important to understand the development of fetal regulatory mechanisms for body fluid homeostasis in this early stage of life. This review focuses on fetal hormonal, behavioral, and renal development related to regulation of body fluids in utero.

Maternal undernutrition and the offspring kidney: from fetal to adult life

Maternal dietary protein restriction during pregnancy is associated with low fetal birth weight and leads to renal morphological and physiological changes. Different mechanisms can contribute to this phenotype: exposure to fetal glucocorticoid, alterations in the components of the renin-angiotensin system, apoptosis, and DNA methylation. A low-protein diet during gestation decreases the activity of placental 11ß-hydroxysteroid dehydrogenase, exposing the fetus to glucocorticoids and resetting the hypothalamic-pituitary-adrenal axis in the offspring. The abnormal function/expression of type 1 (AT1R) or type 2 (AT2R) AngII receptors during any period of life may be the consequence or cause of renal adaptation. AT1R is up-regulated, compared with control, on the first day after birth of offspring born to low-protein diet mothers, but this protein appears to be down-regulated by 12 days of age and thereafter. In these offspring, AT2R expression differs from control at 1 day of age, but is also down-regulated thereafter, with low nephron numbers at all ages: from the fetal period, at the end of nephron formation, and during adulthood. However, during adulthood, the glomerular filtration rate is not altered, due to glomerulus and podocyte hypertrophy. Kidney tubule transporters are regulated by physiological mechanisms; Na+/K+-ATPase is inhibited by AngII and, in this model, the down-regulated AngII receptors fail to inhibit Na+/K+-ATPase, leading to increased Na+ reabsorption, contributing to the hypertensive status. We also considered the modulation of pro-apoptotic and anti-apoptotic factors during nephrogenesis, since organogenesis depends upon a tight balance between proliferation, differentiation and cell death.

Plasma concentrations and placental immunostaining of interleukin-10 and tumornecrosis factor-α as predictors of alterations in the embryo-fetal organism and the placental development of diabetic rats

Interleukin-10 (IL-10) appears to be the key cytokine for the maintenance of pregnancy and inhibits the secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α). However, there are no studies evaluating the profile of these cytokines in diabetic rat models. Thus, our aim was to analyze IL-10 and TNF-α immunostaining in placental tissue and their respective concentrations in maternal plasma during pregnancy in diabetic rats in order to determine whether these cytokines can be used as predictors of alterations in the embryo-fetal organism and in placental development. These parameters were evaluated in non-diabetic (control; N = 15) and Wistar rats with streptozotocin (STZ)-induced diabetes (N = 15). At term, the dams (100 days of life) were killed under anesthesia and plasma and placental samples were collected for IL-10 and TNF-α determinations by ELISA and immunohistochemistry, respectively. The reproductive performance was analyzed. Plasma IL-10 concentrations were reduced in STZ rats compared to controls (7.6 ± 4.5 vs 20.9 ± 8.1 pg/mL). The placental scores of immunostaining intensity did not differ between groups (P > 0.05). Prevalence analysis showed that the IL-10 expression followed TNF-α expression, showing a balance between them. STZ rats also presented impaired reproductive performance and reduced plasma IL-10 levels related to damage during early embryonic development. However, the increased placental IL-10 as a compensatory mechanism for the deficit of maternal regulation permitted embryo development. Therefore, the data suggest that IL-10 can be used as a predictor of changes in the embryo-fetal organism and in placental development in pregnant diabetic rats.

Panic-like defensive behavior but not fear-induced antinociception is differently organized by dorsomedial and posterior hypothalamic nuclei of Rattus norvegicus (Rodentia, Muridae)

The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothalamic nuclei regarding defensive and antinociceptive mechanisms. Thus, the GABA A antagonist bicuculline (40 ng/0.2 µL) or saline (0.9% NaCl) was microinjected into the dorsomedial or posterior hypothalamus in independent groups. Innate fear-induced responses characterized by defensive attention, defensive immobility and elaborate escape behavior were evoked by hypothalamic blockade of GABA A receptors. Fear-induced defensive behavior organized by the posterior hypothalamus was more intense than that organized by dorsomedial hypothalamic nuclei. Escape behavior elicited by GABA A receptor blockade in both the dorsomedial and posterior hypothalamus was followed by an increase in nociceptive threshold. Interestingly, there was no difference in the intensity or in the duration of fear-induced antinociception shown by each hypothalamic division presently investigated. The present study showed that GABAergic dysfunction in nuclei of both the dorsomedial and posterior hypothalamus elicit panic attack-like defensive responses followed by fear-induced antinociception, although the innate fear-induced behavior originates differently in the posterior hypothalamus in comparison to the activity of medial hypothalamic subdivisions.

Exames de imagem na avaliação de anomalias urológicas em lactentes com hidronefrose fetal: avanços e controvérsias

Avanços recentes no diagnóstico pré-natal têm permitido o aprimoramento da detecção e o manejo das anormalidades do trato urinário. A ultrassonografia pré-natal permite o reconhecimento de anormalidades urológicas que somente seriam identificadas tardiamente, após o aparecimento de sintomas ou complicações. A uretrocistografia miccional pode ser reservada para casos selecionados. Exames de medicina nuclear devem ser realizados em casos de hidronefrose moderada e grave. O estudo consistiu de uma revisão da literatura atual sobre a abordagem pós-natal da hidronefrose fetal. Os dados obtidos foram confrontados com a experiência da Unidade de Nefrologia Pediátrica do HC/UFMG na conduta e no seguimento de crianças com diagnóstico de uropatias detectadas na investigação de hidronefrose fetal.

Human fetal malformations associated with the use of an angiotensin II receptor antagonist: Case Report

Introduction: The potential risks related to drug exposure during pregnancy represent a vast chapter in modern obstetrics and data regarding the safety of antihypertensive drugs during pregnancy are relatively scarce. Case report: A 37-year-old patient discovered her fifth pregnancy at our hospital after 26 weeks and 4 days of gestation. She reported a history of hypertension and was currently being treated with Losartan. Hospitalization was recommended for the patient and further evaluation of fetal vitality was performed. On the fourth day an ultrasound was performed, resulting in a severe oligohydramnios, fetal centralization and abnormal ductus venosus. After 36 hours, the newborn died. Pathologic evaluation: At autopsy, the skullcap had large fontanels and deficient ossification. The kidneys were slightly enlarged. A microscopic examination detected underdevelopment of the tubules and the presence of some dilated lumens. Immunohistochemical detection of epithelial membrane antigen was positive. Immunoreactivity of CD 15 was also assayed to characterize the proximal tubules, and lumen collapse was observed in some regions. Discussion: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor antagonists (ARAs) are among the most widely prescribed drugs for hypertension. They are often used by hypertensive women who are considering become pregnant. While their fetal toxicity in the second or third trimesters has been documented, their teratogenic effect during the first trimester has only recently been demonstrated. Conclusion: Constant awareness by physicians and patients should be encouraged, particularly in regard to the prescription of antihypertensive drugs in women of childbearing age who are or intend to become pregnant.

Influência da posição de semeadura na germinação, vigor e crescimento de plântulas de bacabinha (Oenocarpus mapora Karsten - Aecaceae)

A bacabinha (Oenocarpus mapora Karsten) é uma espécie de palmeira que cresce em touceiras de cinco a 12 indivíduos, nativa da Amazônia, podendo ainda ser encontrada em alguns países do norte da América do Sul e da América Central. Seu fruto é utilizado para fabricar refresco, sorvetes e cremes. Extraindo também, de seu estipe palmito, com excelentes características organolépticas e bom rendimento, devido a suas potencialidades essa espécie vem sendo estudada no sentido de domesticá-la. Com o objetivo de verificar o efeito da posição de semeadura na germinação, no vigor e no crescimento das plântulas, foi realizado o experimento, testando-se quatro posições de semeadura com três repetições em parcelas de 25 sementes, sendo instalado em delineamento inteiramente casualizado. Avaliou-se a percentagem, o tempo médio de germinação e o comprimento das plântulas. Os resultados indicaram que a germinação de sementes de bacabinha não foi afetada pela posição de semeadura, alcançando valores acima de 92%, porém, quando as sementes foram postas para germinar com o poro germinativo voltado para a superfície e com a rafe na posição horizontal e voltada para cima, as sementes germinaram em menor tempo. O desenvolvimento inicial das plântulas de bacabinha foi afetado pela posição de semeadura.

Secagem estacionária de sementes de soja com ar desumidificado por resfriamento

O presente trabalho foi realizado com o objetivo de monitorar o processo de secagem de sementes de soja utilizando ar desumidificado por resfriamento. Utilizaram-se sementes de soja, cultivar Campo Mourão, secadas em secador estacionário com distribuição radial do fluxo do ar, modelo Dry-Excel, com capacidade estática para 10 toneladas e o equipamento Dry 60®. O processo de secagem consistiu em remover inicialmente a umidade do ar pelo resfriamento a temperatura abaixo do ponto de orvalho e posterior aquecimento até 33 °C, alcançando umidade relativa de 40%. A secagem ocorreu com fluxo de ar de 17 m³.min-1.t-1. Foram retiradas amostras de sementes no secador a distâncias radiais de até 0,15 m; entre 0,15 e 0,45 m e de 0,45 aos 0,60 m do duto central e nas alturas 0,5; 2,4 e 4,3 m da base do secador. Determinaram-se a remoção de água e temperatura da massa de sementes em intervalos regulares de uma hora, desde o início da secagem, durante seis horas. A qualidade fisiológica das sementes foi avaliada pelos testes de germinação, primeira contagem de germinação, envelhecimento acelerado, porcentagem e índice de velocidade de emergência de plântulas em campo. Concluiu-se que: é possível secar sementes de soja em escala comercial, empregando ar desumidificado por resfriamento e temperaturas reduzidas; pela estrutura do silo secador de tubo central perfurado, há desuniformidade do processo de secagem, com velocidades de secagem e teores de água finais obtidos variando de acordo com a posição das sementes no secador; a qualidade fisiológica das sementes é mantida pelo processo de secagem utilizando ar desumidificado pelo resfriamento e baixas temperaturas, independentemente da posição das sementes no silo secador.

Qualidade de sementes e desenvolvimento inicial de plântulas de pimenta malagueta e sua relação com a posição de coleta de frutos

O objetivo neste estudo foi avaliar a relação entre a posição de coleta dos frutos de pimenta malagueta na planta, a qualidade das sementes e o desenvolvimento inicial das plântulas. As sementes foram obtidas de frutos coletados em diferentes posições na copa (C) e nos ramos (R): 1- apical, 2- mediana e 3- basal, e avaliados o teor de água, peso de mil sementes (PMS), número de sementes por quilo, tamanho de sementes (comprimento, largura e espessura), germinação e vigor pelo índice de velocidade de germinação (IVG), tempo médio de germinação (TMG), comprimento da raiz, parte aérea, massa fresca e massa seca das plântulas após 28 dias da semeadura. As sementes de frutos coletados na porção basal e mediana da copa, e basal dos ramos (C2R3 e C3R3) apresentaram maior PMS, associado ao maior comprimento e largura. Estes tratamentos apresentaram maior valor para a porcentagem de germinação, maior índice de velocidade de germinação e menor tempo médio de germinação. Além do maior vigor, as sementes provenientes de frutos coletados na região basal (C3R3) propiciaram o melhor desenvolvimento inicial de plântulas com relação ao comprimento da raiz, massa fresca e seca de plântulas.

Estado e economia na Coreia do Sul - do Estado desenvolvimentista à crise asiática e à recuperação posterior

The State and the economy in South Korea: from the developmentist state to the Asian crisis and later recovery. The article focuses on the institutions of South Korean capitalism and on the interactions between the state and the economy. The economic model in South Korea was characterized by a very interventionist state, which played a very active role in the process of industrialization. However, South Korea suffered a severe crisis in 1997, attributed by many authors to the distortions inherent to strong state intervention. The article shows that the crisis was a result of the combination between internal economic fragilities and a rapid process of financial deregulation, which undermined the state's capacity of control. The crisis, nevertheless, does not disqualify the role of the national institutions in the very successful process of industrialization. Despite the reforms, the Korean capitalism conserves much of the previous model of business organization and industrial relations. The state continues strong and played active role in the process of economic reforms. There are, nevertheless, doubts about the impacts of the reforms and the new configuration of Korean capitalism. They will depend on the current transformations in world economy and in the East Asian countries.

Vulnerabilidade externa e composição da posição internacional de investimentos: Brasil 2001-2010

The aim of this paper is to indicate that there was a significant change in the composition of the Brazilian International Investment Position in the period 2001-2010: international reserves became higher than the external debt and decreased the share of foreign liabilities denominated in foreign currency, getting smaller that the participation of the external liabilities denominated in domestic currency. These tend to suffer a double devaluation (prices and exchange rates) in times of crisis, thus characterizing the reduction of the external vulnerability in the financial sphere as evidenced in the global crisis hatched in 2008.

Posição original e equilíbrio reflexivo em John Rawls: o problema da justificação

O objetivo deste artigo é estabelecer algumas considerações sobre o papel dos procedimentos de posição original e equilíbrio reflexivo na teoria da justiça como equidade de John Rawls, nas obras A Theory of Justice, Political Liberalism e Justice as Fairness: A Restatement. Eu pretendo mostrar que Rawls faz uso de um modelo coerentista-pragmático de justificação dos princípios de justiça em um âmbito público, que é não-fundacionalista em razão da interconexão entre estes procedimentos.