Design and optimization of an experimental maintenance system for yellow clam broodstock Amarilladesma mactroides (Reeve, 1854) / Desenvolvimento e otimização de um sistema de manutenção experimental para reprodutores de marisco branco Amarilladesma mactroides (Reeve, 1854)

The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor and oocyte diameter, and a relative advancement of gonadal development.

O marisco branco é um bivalve de areia que habita as praias dissipativas do sul do Brasil até a costa norte da Argentina. Nas últimas décadas, as populações desta espécie têm sido afetadas por eventos de mortalidade maciça, sobrepesca e outras atividades antropogênicas. A produção de juvenis em cativeiro permitiria a realização de estudos de viabilidade para restaurar o estoque natural, assim como a produção em sistemas de aquicultura. Dada a escassez de estudos sobre a manutenção desta espécie em cativeiro, um sistema de cultivo e um protocolo de manejo foram desenvolvidos e testados. Mariscos branco selvagens (comprimento total ≥50 mm) foram utilizados em uma série de ensaios de 14 dias de duração. A sobrevivência foi maior nos mariscos que podiam ser enterrados na areia. Um marcador de tinta permanente coberto com uma fina camada de adesivo de endurecimento rápido provou ser um método confiável para marcar os mariscos. A manutenção dos mariscos neste sistema resultou em alta sobrevivência e crescimento, aumento do fator de condição e do diâmetro do ovócito, e um relativo avanço do desenvolvimento gonadal.

Design and optimization of an experimental maintenance system for yellow clam broodstock Amarilladesma mactroides (Reeve, 1854)

Abstract The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length 50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor and oocyte diameter, and a relative advancement of gonadal development.

Resumo O marisco branco é um bivalve de areia que habita as praias dissipativas do sul do Brasil até a costa norte da Argentina. Nas últimas décadas, as populações desta espécie têm sido afetadas por eventos de mortalidade maciça, sobrepesca e outras atividades antropogênicas. A produção de juvenis em cativeiro permitiria a realização de estudos de viabilidade para restaurar o estoque natural, assim como a produção em sistemas de aquicultura. Dada a escassez de estudos sobre a manutenção desta espécie em cativeiro, um sistema de cultivo e um protocolo de manejo foram desenvolvidos e testados. Mariscos branco selvagens (comprimento total 50 mm) foram utilizados em uma série de ensaios de 14 dias de duração. A sobrevivência foi maior nos mariscos que podiam ser enterrados na areia. Um marcador de tinta permanente coberto com uma fina camada de adesivo de endurecimento rápido provou ser um método confiável para marcar os mariscos. A manutenção dos mariscos neste sistema resultou em alta sobrevivência e crescimento, aumento do fator de condição e do diâmetro do ovócito, e um relativo avanço do desenvolvimento gonadal.

Design and optimization of an experimental maintenance system for yellow clam broodstock Amarilladesma mactroides (Reeve, 1854) / Desenvolvimento e otimização de um sistema de manutenção experimental para reprodutores de marisco branco Amarilladesma mactroides (Reeve, 1854)

The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor and oocyte diameter, and a relative advancement of gonadal development.

O marisco branco é um bivalve de areia que habita as praias dissipativas do sul do Brasil até a costa norte da Argentina. Nas últimas décadas, as populações desta espécie têm sido afetadas por eventos de mortalidade maciça, sobrepesca e outras atividades antropogênicas. A produção de juvenis em cativeiro permitiria a realização de estudos de viabilidade para restaurar o estoque natural, assim como a produção em sistemas de aquicultura. Dada a escassez de estudos sobre a manutenção desta espécie em cativeiro, um sistema de cultivo e um protocolo de manejo foram desenvolvidos e testados. Mariscos branco selvagens (comprimento total ≥50 mm) foram utilizados em uma série de ensaios de 14 dias de duração. A sobrevivência foi maior nos mariscos que podiam ser enterrados na areia. Um marcador de tinta permanente coberto com uma fina camada de adesivo de endurecimento rápido provou ser um método confiável para marcar os mariscos. A manutenção dos mariscos neste sistema resultou em alta sobrevivência e crescimento, aumento do fator de condição e do diâmetro do ovócito, e um relativo avanço do desenvolvimento gonadal.

Design and optimization of an experimental maintenance system for yellow clam broodstock Amarilladesma mactroides (Reeve, 1854).

The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor and oocyte diameter, and a relative advancement of gonadal development.

Hemangioma esclerosante mandibular em Paralichthys orbignyanus: relato de caso / Sclerosing hemangioma mandibular in Paralichthys orbignyanus: case report

Neste trabalho, descreveu-se o primeiro caso de hemangioma esclerosante registrado em um exemplar adulto do linguado Paralichthys orbignyanus. Produzido a partir de reprodução artificial, o peixe em questão tinha aproximadamente 10 anos de idade e fazia parte de um plantel de reprodutores. Ao ser retirado do tanque, notou-se a presença de lesão mandibular com escoriações e focos hemorrágicos. Amostras do tumor foram coletadas da mandíbula para análise histopatológica. Microscopicamente foi observada uma proliferação de numerosos vasos sanguíneos rodeados por um estroma conectivo denso. A etiologia dessa neoplasia é desconhecida, mas o fato de o exemplar ter permanecido por muitos anos em cativeiro pode ter contribuído para o surgimento desse tipo de lesão, devido aos choques mecânicos contra a parede do tanque que acontecem esporadicamente.(AU)

In this study, we described the first case of sclerosing haemangioma in an adult Brazilian flounder Paralichthys orbignyanus. Produced by artificial reproduction, the fish was approximately 10 years old and was maintained at a breeding stock. When removed from the tank, mandibular lesion with excoriations and hemorrhagic foci were noted. Tumor samples were collected from the mandible for histopathological analysis. Proliferation of numerous blood vessels surrounded by dense connective stroma was observed microscopically. The etiology of this neoplasia is unknown, but the fact that the specimen remained in captivity for many years, may have contributed to the appearance of this type of lesion, due to sporadic mechanical shocks to the tank wall.(AU)

Hiperplasia em túnicas de artérias coronárias de beijupirás criados em sistema offshore / Hyperplasia in tunics of coronary arteries in beijupirá farmed in offshore system

As lesões coronarianas já foram relatadas em espécies de peixes anádromos, com características semelhantes às observadas em aterosclerose humana, mas não em peixes cultivados sem interferência de padrões reprodutivos. Objetivou-se descrever lesões coronarianas em beijupirá (Rachycentron canadum) criado em sistema offshore, em 54 exemplares coletados ao longo do cultivo de oito meses. Amostras de tecido cardíaco de alevinos e juvenis foram submetidas à análise histopatológica e à microscopia eletrônica de transmissão (MET), para visualização de lesões coronarianas, sendo as lâminas histológicas coradas pela técnica de hematoxilina-eosina, ácido periódico de Schiff, alcian blue e reticulina de Gomori. Exames realizados pela fotomicroscopia de luz evidenciaram lesões arteriais caracterizadas por hiperplasia das túnicas íntima e média de artérias coronárias em, respectivamente, 29,63% e 79,63% dos animais, com redução do lúmen arterial. Na MET, foram observadas alterações na estrutura das coronárias com espessamento do endotélio e membrana basal, proliferação de fibroblastos e fibras colágenas, com acúmulo de material lipídico subendotelial, resíduos celulares aderidos à membrana basal e vesículas pinocitóticas com presença de lisossomos isolados. Constatou-se que os peixes da espécie Rachycentron canadum criados em cativeiro desenvolvem lesão arterial do tipo crônica degenerativa inflamatória.

The coronary lesions have been reported in species of anadromous fish with similar characteristics as those observed in human atherosclerosis, but not in farmed fish without interference of reproductive patterns. This study aimed to describe coronary lesions in beijupirá (Rachycentron canadum) farmed in an offshore system, in 54 specimens collected along an eight month cultivation period. Samples of heart tissue of fry and juveniles were subjected to histopathological analysis and transmission electron microscopy (TEM) for visualization of coronary lesions, the histology slides were stained using hematoxylin-eosin, periodic acid Schiffh, alcian blue, and reticulin of Gomori. Examinations performed by light microscopy showed arterial lesions characterized by hyperplasia of the intima and media tunics, respectively in 29.63% and 79.63 % of the animals, with reduced lumen. In TEM changes in the structure of the coronary endothelium and thickening of the basement membrane, proliferation of fibroblasts and collagen fibers, with subendothelial accumulation of lipid material, cellular debris adhering to the basement membrane and presence of pinocytotics vesicles and isolated lysosomes were observed. It has been found that the Rachycentron canadum fish species farmed in captivity develop arterial lesion of the chronic inflammatory degenerative type.

Effect of low salinity on the yellow clam Mesodesma mactroides.

The aim of this study was to determine the lethal salinity (LC50) for the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) and identify histopathological alterations that could be used to diagnose structural changes in clam tissue. Clams in two size classes (adults and juveniles) were placed in 10 L chambers and exposed to salinities of 35, 30, 25, 20, 15, 10, and 5 g/L. There were triplicate chambers with seven clams each for each salinity. The LC50 values for a 48 h exposure were 6.5 g/L and 5.7 g/L for adults and juveniles, respectively. For a 96 h exposure, the LC50 values were 10.5 g/L for adults and 8.8 g/L for juveniles. The histological examination of yellow clams exposed to 10 g/L for 96 h showed intercellular oedema and necrotic foci in the epithelium of the digestive gland and occlusion of the lumen of the digestive gland. In conclusion, M. mactroides can be characterised as a moderately euryhaline species, tolerating salinities from 35 to 15 g/L.

Antioxidant and toxicological effects elicited by alpha-lipoic acid in aquatic organisms.

Lipoic acid (LA) is a disulfide-containing compound derived from octanoic acid that is synthesized in mitochondria. This molecule acts as a co-factor for mitochondrial enzymes that catalyze oxidative decarboxylation reactions. Several antioxidant properties of LA enable it to be considered as an "ideal antioxidant", having diverse benefits that allow it to deal with environmental or biological stress. Some of the effects induced by LA in aquatic organisms render it suitable for use in aquaculture. However, it is necessary to determine the appropriate dose(s) to be used with different species and even organs to maximize the beneficial antioxidant and detoxifying effects and to minimize the pro-oxidant toxic effects. This review analyzes and compiles existing data from aquatic organisms in which both benefits and drawbacks of LA have been described.

Increases in cytosolic Ca2+ are not required for abscisic acid-inhibition of inward K+ currents in guard cells of Vicia faba L.

The inward K+ channels (IKin) of guard cells are inhibited upon application of abscisic acid (ABA). It has been postulated that I(Kin) inhibition requires an elevation in cytosolic free Ca2+ levels ([Ca2+]c) because: (i) experimental increases in [Ca2+]c can mimic the ABA effect, and; (ii) ABA can trigger an elevation of [Ca2+]c in guard cells. However, not all guard cells respond to ABA with a [Ca2+]c increase, and the magnitude of the increases that do occur is variable. Therefore, an obligate role for Ca2+ in the regulation of downstream effectors of ABA response, such as the I(Kin) channels, remains in question. In this study, we developed a methodology for simultaneous patch clamping and confocal ratiometric Ca2+ imaging of Vicia faba L. guard-cell protoplasts. This allowed us to directly assess the relationship between ABA-induced changes in [Ca2+]c and I(Kin) inhibition. In the presence of extracellular Ca2+, the extent of [Ca2+]c elevation correlated with the extent of I(Kin) inhibition. However, upon chelation of either extracellular Ca2+, [Ca2+]c or both, extracellular Ca2+ and [Ca2+]c, [Ca2+]c elevation did not occur in response to ABA yet I(Kin) currents were still strongly inhibited. These data illustrate that Ca2+-independent regulation is involved in ABA-inhibition of stomatal opening processes.

Slug is an essential target of TGFbeta2 signaling in the developing chicken heart.

An epithelial-mesenchymal cell transformation (EMT) occurs during the development of endocardial cushions in the atrioventricular (AV) canal of the heart. This is a complex developmental process regulated by multiple extracellular signals and signal transduction pathways. It was recently shown that the transcription factor Slug is expressed in the AV canal and is required for initial steps of EMT. Treatment of AV canal explants with either antisense oligodeoxynucleotides toward Slug or anti-TGFbeta2 antibody inhibited initial steps of EMT. Others have identified roles for HGF and BMP during EMT in the heart. Both HGF and BMP are known to regulate Slug in other cell types. To determine whether TGFbeta2 or other signaling factors regulate Slug expression during EMT in the heart, we cultured AV canal explants in the presence of anti-TGFbeta2 antibody, anti-TGFbeta3 antibody, pertussis toxin, retinoic acid, noggin, or anti-HGF antibody. Only treatment with anti-TGFbeta2 antibody or retinoic acid inhibited Slug expression in AV canal explants. Consistent with these data, we found that retinoic acid disrupted initial steps of EMT, while antagonists of BMP and HGF signaling disrupted later steps of EMT. Transfection of AV canal explants with Slug rescued the inhibitory effect of anti-TGFbeta2 antibody but not retinoic acid on EMT. Slug is thus an essential target of TGFbeta2 signaling during EMT in the developing chicken heart.

Kinetic analysis of the K(+)-selective outward rectifier in Arabidopsis mesophyll cells: a comparison with other plant species.

This paper gives a kinetic analysis of the K(+)-selective outward-rectifier (IK,out) in the plasma membrane of Arabidopsis thaliana mesophyll cells in terms of the Hodgkin-Huxley formalism. We compared the kinetic characteristics of IK,out in Arabidopsis with IK,out channels in three other plant species that were subjected to a similar analysis: tobacco suspension cells, Vicia faba guard cells and Plantago media root cells. Because the activation kinetics of IK,out shows a clear voltage dependence, the time constant of half-activation (tau 1/2) and the elementary rate constant of channel opening (a) were calculated at the potential of half-activation (V1/2). The Arabidopsis IK,out activates relatively slowly and this is reflected in a tau 1/2 of approximately 1 s. The reason for this slow activation is twofold. Firstly, the value of a is 1.5 s-1 falls at the lower end of the range of values obtained for tobacco, Vicia and Plantago: 1.1 to 3.0 s-1. Secondly, IK,out in Arabidopsis has four closed states, while tobacco and Vicia have only two. As observed in other plant species, the activation kinetics of IK,out in Arabidopsis are sensitive to external K+: V1/2 shifts with EK but remains approximately 50 mV more positive than EK.

Utilization of antisense oligodeoxynucleotides with embryonic tissues in culture.

Experimental embryology has long used manipulation of interacting tissues to examine questions of tissue interaction and differentiation. The potential for specific manipulation of gene expression in such tissues has made the utilization of antisense techniques desirable. However, problems with this methodology have discouraged many investigators from using this approach. Selection of target sequences for antisense oligonucleotides, delivery of oligonucleotides into cells or tissues, and the type of modification of the oligonucleotide to be used all present concerns that must be addressed. This paper describes our approach to selection of target sequence and methods of delivery and describes the synthesis of a methoxyethylamidate-modified antisense oligonucleotide that has proved useful in our studies. This approach has enabled us to explore aspects of tissue interaction in the embryonic heart that would have been difficult to explore in a genetic model.

Slug is a mediator of epithelial-mesenchymal cell transformation in the developing chicken heart.

An epithelial-mesenchymal cell transformation occurs during the development of the endocardial cushions in the atrioventricular (AV) canal of the heart. We hypothesized that the transcription factor Slug is required for this epithelial-mesenchymal cell transformation since Slug is required for similar transformations during gastrulation and neural crest differentiation in chicken embryos. We found by RT-PCR and immunostaining that the temporal and spatial localization of Slug in the embryonic chicken heart is consistent with a role for Slug in endocardial cushion formation. Moreover, we found that Slug expression by AV canal endothelial cells is induced by a signal provided by AV canal myocardium. Slug appears to be required for epithelial-mesenchymal cell transformation in the chicken heart since treatment of AV canal explants with antisense Slug oligodeoxynucleotides inhibited mesenchymal cell formation in vitro. Antisense Slug oligodeoxynucleotides prevented endothelial cell-cell separation, suggesting that Slug acts early in the transformation pathway.

Biomolecular changes in the aging myocardium: the effect of enalapril.

Chronic administration of enalapril in the aging mouse prevents myocardial fibrosis. To investigate the mechanisms involved, we studied 30 CF1 female mice that received enalapril (ENAL:20 mg/L) in their drinking water after weaning and 30 control (CONT) mice. Ten animals from each group were killed at 12, 18, and 24 months. Half of the samples were prepared for light microscopy (LM) and the other half for electron microscopy (EM). Cardiac histologic sections were studied by an image analyzer (Bioscan OPTIMAS 4.1). We performed the following measurements in cardiomyocytes: mitochondrial number, mitochondrial superoxide dismutase (SOD) using immunohistochemical methods with EM, the percentage of cell cyclin, and apoptosis. The results obtained for CONT and ENAL, respectively were as follows. For cyclin (percentage of positive) our results were: 12 months 17.1+/-0.1% and 18.2+/-0.8%, 18 months 2.4+/-1.6% (P < .001), and 11.4+/-0.1% (P < .001), 24 months 1.2+/-1.3% (P < .001), and 8.2+/-1.2% (P < .001) with significant differences at 18 and 24 months. For the Feulgen method (cell/mm2) we found: 12 months CONT 89.7+/-1.2, ENAL 84.6+/-1.2; 18 months CONT 62.8+/-1.2, ENAL 98.7+/-1.3, and 24 months CONT 81.2+/-1.3, ENAL 112.3+/-1.4. Apoptosis (percentage of positive) was found to be 12 months 3.7+/-0.4% and 1.9+/-0.1%, 18 months 7.1 +/-0.3% (P < .001), and 1.5+/-0.1% (P < .001), 24 months 10.9+/-0.5% (P < .001) and 2.1+/-1.8% (P < .001), for CONT and ENAL, respectively; there were significant differences at 18 and 24 months. The number of mitochondria per cardiomyocyte were: 12 months 85.9+/-1.8 and 87.3+/-1.5, 18 months 69.2+/-1.5t and 82.2+/-1.8 (P < .001), 24 months 54.6+/-1.1 (P < .001) and 81.4+/-1.6 (P < .001) for CONT and ENAL respectively, with significant differences at 18 and 24 months. Mitochondrial SOD was found to be: 12 months 13.6%+/-0.2% (P < .05) and 17.8%+/-1.3% (P < .05), 18 months 7.1%+/-1.0% (P < .001) and 16.7%+/-1.6% (P < .001), 24 months 4.1%+/-0.5% (P < .001), and 12.4%+/-0.9% (P .001) for CONT and ENAL respectively, with significant differences at 12 months and at 18 and 24 months (ANOVA and contrast Scheffe's test). We conclude that chronic administration of ENAL modifies mitochondrial SOD at 12 months, whereas at 18 and 24 months ENAL was associated with higher mitochondrial SOD and a higher mitochondrial number with a greater cyclin expression, and a lower percentage of apoptosis. Enalapril may prevent myocardial fibrosis, possibly by causing changes related to enzymatic-mitochondrial or cellular cycle modifications.

Ca(2+)-permeable, outwardly-rectifying K+ channels in mesophyll cells of Arabidopsis thaliana.

Arabidopsis thaliana has become a powerful tool in genetics and molecular biology. In order to use Arabidopsis as a model system for electrophysiological studies on plant cells, a detailed characterization of the transporters present in the plasma and vacuolar membranes of this species is required. We used the patch-clamp technique to study ion channels in the plasma membrane of Arabidopsis mesophyll cells. The most prominent conductance in these cells was a K(+)-selective, voltage-dependent, outwardly-rectifying channel (IK,out). In the whole-cell configuration, IK,out was observed in 100% of the cells assayed. In contrast, inward current was observed in less than 50% of the cells which were bathed in 100 mM K+, and was totally absent from cells bathed in 10 mM K+. The activation kinetics of IK,out were modulated by the external K+ concentration with a faster activation at low external K+. Tail-current analysis revealed that in addition to K+, IK,out is also permeable to Ca2+ and Ba2+. Externally applied Ba2+ also caused a voltage-dependent decrease in current magnitude, indicating that IK,out is also partially blocked by this classic K+ channel blocker. Single channels studied in outside-out patches showed Ca2+ and Ba2+ sensitivity, voltage dependence and time activation similar to that of IK,out in the whole-cell configuration. Given their permeability to Ca2+, these channels may function as an avenue for Ca2+ influx as well as K+ efflux, both of which may affect photosynthesis.

Renal interstitial sclerosis in aging: effects of enalapril and nifedipine.

The effects of nifedipine and enalapril on age-associated renal interstitial fibrosis were investigated in 60 CF1 female mice. Mice received 20 mg enalapril (ENAL) per L (N = 20), or 40 mg nifedipine (NIF) per L (N = 20) in their drinking water. Control (CONT) mice received tap water ad libitum. The percentages of both interstitial peritubular sclerosis (IPS) in cortex and interstitial medullary sclerosis (IMS) were determined. Kidney tissue was studied using immunological techniques and optical (OM) and electron microscopy (EM) to analyze the expression of renin. alpha-SM-actin and vimentine expression were also evaluated. The results showed that blood pressure levels in ENAL or NIF animals were not different from those of CONT. Renin expression was observed in arcuate vessels (AV) in ENAL animals, whereas no renin staining in AV was found in either NIF or CONT animals. Renin immunoreactivity in the juxtaglomerular apparatus was more intense in ENAL mice, as compared with NIF or CONT animals. Laboratory testing showed the following values: proteinuria (mg/mL): CONT 6.1 +/- 0.6, NIF 11.2 +/- 2.3, and ENAL 1.0 +/- 0.6 (P < 0.05); creatinine: CONT 1.37 +/- 0.24, NIF 0.87 +/- 0.16, and ENAL 0.63 +/- 0.1 (P < 0.01). The percentages of interstitial sclerosis were: %IPS: CONT 18.12 +/- 1.1, NIF 17.40 +/- 0.9, and ENAL 3.42 +/- 1.3 (P < 0.01); %IMS: CONT 23.41 +/- 1.5, NIF 21.80 +/- 1.9, and ENAL 6.12 +/- 1.2 (P < 0.01). Percentages of alpha-SM-actin expression were: CONT 13.10 +/- 1.9, NIF 13.80 +/- 0.2, and ENAL 1.00 +/- 0.1 (P < 0.01). Vimentine staining showed no differences among the groups. It was concluded that enalapril reduces the peritubular and medullar interstitial fibrosis, whereas nifedipine has no effect.

Ultrastructural modifications and changes in the expression of hormonal genes produced by indomethacin in the anterior pituitary gland of the rat.

Indomethacin decreases the level of prolactin (50%) and growth hormone (70%) mRNA in the anterior pituitary gland of the rat. Actin mRNA increases (59%). Ultrastructurally there is a decrease in the number of secretory granules. Indomethacin also prevents the increase in prolactin secretory granules produced by the administration of estradiol. The results indicate that indomethacin inhibits hormonal synthesis in the APG at a transcriptional level. This effect appears selective because mRNA level for actin synthesis in the pituitary gland was higher than in nontreated rats.

Síntesis de renina por células renales durante la inhibición crónica de la enzima convertidora de la angiotensina I / Renin synthesis by renal cells during chronic inhibition of angiotensin I converting enzyme

Se realizó un estudio sobre la síntesis de renina y las modificaciones en el número de células que se produce durante la inhibición crónica de la enzima convertidora de la Ang II en ratones. Veinte ratones CF1, hembras de 15 días de edad, inmediatamente después del destete, recibieron 20 mg/l de maleato de enalapril (ME) con el agua de beber durante 18 meses y se compararon con un grupo control. El tejido renal fue procesado y estudiado con técnicas inmunohistoquímicas con microscopía óptica y electrónica utilizando un anticuerpo policlonal antirrenina y se realizó hibridización in situ para rasteo de ARNm de renina con una sonda marcada con diagoxigenina. Los parámetros calculados fueron el número de aparatos yuxtaglomerulares (MAYG), de arteriolas aferentes (AA) y vasos arcuatos (VA) inmunomarcados con antirrenina y con antidigoxigenina. Con microscopía electrónica se determinó el número de partículas de oro por gránulo de renina. Se demostró aumento del número de células productoras de renina en los animales que recibieron crónicamente ME, más allá del AYG y de la AA ya que se observó marcación en vasos arcuatos. La media de porcentagem MAYG y porcentagemMAA fue menor en los animales controles (Con) que en los tratados (TRA). No se marcaron los VA en el grupo Con, y sí en los animales Tra. La distribución del ARN fue diferente en los animales con inhibición del SRA que en los controles. Los signos de hibridización fueron significativamente menores en los animales Con, tanto el porcentagemSAYG, el porcentagemSAA. En los VA sólo se observaron signos en los animales tratados porcentagem SVA. La cantidad de partículas de oro en las células productoras de renina fue diferente entre los dos grupos de animales. La media del número de partículas de oro en los gránulos de renina perteneciente al AYG de los animales Con. fue significativamente menor que en los tratados. En este trabajo se demostró que los animales que tienen inhibido crónicamente la producción de Ang II por ME, aumentan la síntesis, el número y la localización de células productoras de renina en la vasculatura renal, recapitulando situaciones que ocurren durante el desarrollo embriológico de mamíferos y en vertebrados primitivos adultos