15 research outputs found
Chromosomal variability in the wild ornamental species of Symphysodon (Perciformes: Cichlidae) from Amazon
Cytogenetic studies were conducted on three discus species which inhabit the Amazon in Brazil: Symphysodon haraldi from Manacapuru, S. aequifasciatus from Tefé and S. discus from Barcelos. All individuals showed 2n=60 chromosomes, most of them biarmed. No sexual chromosomal heteromorphism was verified. However, different karyotypic formulae, owing to the presence of subtelocentric chromosomes, were verified for S. aequifasciatus and S. discus. One of the karyotypic formulae from S. aequifasciatus (cytotype 2) differs from the others, due to one of the homologues in the first chromosome pair being significantly larger than the other. A large variability was observed toward the nucleolar organizer regions (NOR) of S. haraldi and S. aequifasciatus. Although the number of silver-stained blocks varied from 2 to 5, confirming different NOR patterns, at least seven homologue pairs were involved with NORs. In S. discus only two marks were observed, however two chromosome pairs were involved, characterizing a multiple NOR system for the three species. The heterochromatic blocks were mainly located in the pericentromeric region of all chromosomes but, in some of them, they are also located in the proximal regions, both in the short and long arms. Moreover, in the cytotype 2 from S. aequifasciatus, an interstitial heterochromatic block was observed on the long arm of the largest homologue of the first pair. A direct comparison of karyotypes from more related genera (Heros, Uaru, Mesonauta and Pterophyllum), makes it clear that a succession of chromosomal rearrangements, mainly pericentric inversions, translocations and fissions/fusions occurred resulting in the present diploid number and intraspecific karyological variability found in Symphysodon. Copyright © 2008 Sociedade Brasileira de Ictiologia
Mineralocorticoid Receptor in Calcium Handling of Vascular Smooth Muscle Cells
For decades, the mineralocorticoid receptor (MR) antagonists have been used for the management of cardiovascular diseases; however, the molecular mechanisms involved in their beneficial effects are not fully understood. Recent publications point to the fundamental role of aldosterone and vascular MR in the regulation of arterial tone, vascular contractility, and cell proliferation. However, the intricate transduction machinery activated by vascular MRs has begun to be revealed with the help of transgenic rodent models and novel transcriptional analysis approaches. Specifically, in this chapter, we review and discuss the most recent contributions about the fine-tuning that the MR exerts on the expression and function of ion channels that participate in calcium handling of vascular cells and the therapeutic implications for hypertension and cardiovascular diseases
Are 30 minutes of rest between two incremental shuttle walking tests enough for cardiovascular variables and perceived exertion to return to baseline values?
Objective: To verify whether 30 minutes of rest between two incremental shuttle walking tests (ISWT) are enough for cardiovascular variables and perceived exertion to return to baseline values in healthy subjects in a broad age range. Method: The maximal exercise capacity of 334 apparently healthy subjects (age ≥18) was evaluated using the ISWT. The test was performed twice with 30 minutes of rest in between. Heart rate (HR), arterial blood pressure (ABP), dyspnea, and leg fatigue were evaluated before and after each test. Subjects were allocated to 6 groups according to their age: G1: 18-29 years; G2: 30-39 years; G3: 40-49 years; G4: 50-59 years; G5: 60-69 years and G6: ≥70 years. Results: All groups had a good performance in the ISWT (median >90% of the predicted distance). The initial HR (HRi) of the second ISWT was higher than the first ISWT in the total sample (p<0.0001), as well as in all groups (p<0.0001). No difference was observed in the behavior of ABP (systolic and diastolic) and dyspnea between the two tests, but this difference occurred for leg fatigue (greater before the second ISWT) in G1 (p<0.05). Most subjects (58%) performed better in the second test. Conclusion: 30 minutes of rest between two ISWTs are not enough for all cardiovascular variables and perceived exertion to return to baseline values. However, this period appears to be sufficient for blood pressure and performance to recover in most subjects
Placental lesions associated with abortion and stillbirth in goats naturally infected by Neospora caninum
Neospora caninum é descrito como
um parasito que causa problemas reprodutivos esporádicos
em cabras. Muitos aspectos da patogênese da neosporose em cabras naturalmente infectadas ainda precisam ser
estabelecidos. Os objetivos deste trabalho foram caracterizar
as lesões placentárias em cabras naturalmente infectadas por
N. caninum e avaliar as técnicas diagnósticas para a detecção
efetiva do protozoário na placenta. Algumas placentas deste
estudo são originárias de abortos e natimortos, nas quais havia
lesões graves. As lesões foram classificadas principalmente
por necrose envolvendo o mesênquima das vilosidades
coriônicas e células trofoblásticas, geralmente associadas
a infiltrado inflamatório mononuclear e em alguns casos
infiltrado neutrofílico. O DNA do N. caninum foi detectado
nestas placentas, porém estruturas parasitárias não foram
visualizadas na imuno-histoquímica (IHQ). Entretanto, cinco
das onze placentas de cabras infectadas, que deram à luz a conceptos saudáveis, apresentaram lesões histológicas
caracterizadas por infiltrado inflamatório mononuclear.
Destas 11 placentas, foi detectado DNA de N. caninum em
sete e taquizoítos foram encontrados em apenas uma por
meio de imuno-histoquímica. O presente estudo demonstra
que abortos e natimortos na espécie caprina, causados pelo
N. caninum estão associados a lesões acentuadas nas placentas,
sendo que as mesmas estão envolvidas na patogênese do
aborto. Os resultados também ressaltam a importância do
uso de mais de uma técnica diagnóstica para a detecção
do protozoário em placentas, pois o N. caninum não pode
ser confiavelmente detectado somente pelos exames de
histopatologia e imuno-histoquímica.Neospora caninum has been described as a parasite that sporadically causes reproductive
problems in goats. Several aspects of the pathogenesis of neosporosis in naturally infected
goats remain to be established. The aims of the present study were to characterize the
placental lesions in goats naturally infected by N. caninum and to evaluate several diagnostic
techniques for effective detection of this protozoan in the goat placenta. Some placentas
in this study originated from abortion and stillbirth in which there were severe lesions.
The lesions were characterized mainly by necrosis involving the mesenchyme of the
chorionic villi and trophoblast cells often alongside mononuclear inflammation and in some
cases with neutrophilic infiltration. N. caninum DNA was detected in these placentas, but
parasite structures were not visualized through immunohistochemistry (IHC). However, five
of 11 placentas from N. caninum-infected goats that gave birth to healthy kids had histological
lesions characterized by mononuclear inflammation. Of these 11 placentas, N. caninum DNA
was detected in seven, and N. caninum tachyzoites were detected in only one of these seven
placentas using IHC. The present study demonstrates that severe lesions in the placenta are
associated with abortion and stillbirth in caprine neosporosis and the placental alterations
are likely involved in abortion pathogenesis. Moreover, the results highlight the importance
of using more than one diagnostic technique for the detection of the protozoan in placentas
because N. caninum cannot be reliably detected by histological and immunohistochemical tests
Placental lesions associated with abortion and stillbirth in goats naturally infected by Neospora caninum
ABSTRACT: Neospora caninum has been described as a parasite that sporadically causes reproductive problems in goats. Several aspects of the pathogenesis of neosporosis in naturally infected goats remain to be established. The aims of the present study were to characterize the placental lesions in goats naturally infected by N. caninum and to evaluate several diagnostic techniques for effective detection of this protozoan in the goat placenta. Some placentas in this study originated from abortion and stillbirth in which there were severe lesions. The lesions were characterized mainly by necrosis involving the mesenchyme of the chorionic villi and trophoblast cells often alongside mononuclear inflammation and in some cases with neutrophilic infiltration. N. caninum DNA was detected in these placentas, but parasite structures were not visualized through immunohistochemistry (IHC). However, five of 11 placentas from N. caninum-infected goats that gave birth to healthy kids had histological lesions characterized by mononuclear inflammation. Of these 11 placentas, N. caninum DNA was detected in seven, and N. caninum tachyzoites were detected in only one of these seven placentas using IHC. The present study demonstrates that severe lesions in the placenta are associated with abortion and stillbirth in caprine neosporosis and the placental alterations are likely involved in abortion pathogenesis. Moreover, the results highlight the importance of using more than one diagnostic technique for the detection of the protozoan in placentas because N. caninum cannot be reliably detected by histological and immunohistochemical tests