Effects of short-term exposure to genistein and overfeeding diet on the neural and retinal progenitor competence of adult zebrafish (Danio rerio).

Neurogenesis is a process that occurs throughout the life of a vertebrate. Among the different factors that may affect the natural occurrence of neurogenesis, obesity seems to decrease the proliferation capacity of progenitor neuronal cells. Conversely, the phytoestrogen genistein is known to attenuate some obesity effects beyond its neuroprotective action. Aiming to improve the understanding of how obesity and genistein trigger an impact on the neural and retinal progenitor competence of adult zebrafish, fish were exposed to genistein (GEN - 2 µg L-1) alone or combined with two dietary groups (control and overfeed - OFD) for up to 9 weeks. Zebrafish were fed once per day with Artemia sp. in the control and GEN (2% of BW, control diet), and three times per day in the OFD and OFD + GEN groups (12% BW, overfeeding diet). To assess obesity induction, BMI, biometric parameters, and PPAR-γ protein were quantified. Afterwards, qRT-PCR and immunohistochemistry were performed to determine the cell proliferation and the presence of stem cells through PCNA and Sox-2. Our findings proved that overfeeding adult zebrafish increased the general growth and induced the development of fatty liver. However, for OFD + GEN, this effect was assuaged through the anti-adipogenic effect of GEN. This finding suggests that phytoestrogens could be beneficial to reduce the negative effects of obesity. Moreover, OF induced negative effects on retinal and brain homeostasis, decreasing the proliferation capacity of progenitor neuronal cells. With regard to retinal progenitor competence, genistein seems to mitigate the negative impacts of obesity, whereas the effects of obesity on the brain were exacerbated by this phytoestrogen which negatively influenced the homeostasis of zebrafish neural progenitor competence. This study highlighted the fact that the effects of phytoestrogens in adult neural progenitor competence are complex and could exhibit dissimilar effects depending on the tissue.

Gill histopathological and oxidative stress evaluation in native fish captured in Portuguese northwestern rivers.

The Northwestern Portuguese region is densely populated and highly industrialized, suffering from high anthropogenic pressure. To assess the biological effect of the several pollutants that are constantly released to the water, a biomarker-based biomonitoring is a promising approach that may provide early-warning signals of pollutants exposure. Fish gill is the first target of pollutants action, thus histopathological and biochemical changes may constitute potential biomarkers. To evaluate this hypothesis, three native fish species (barbel-Luciobarbus bocagei, chub-Squalius carolitertii and nase-Pseudochondrostoma sp.) were sampled in Northwestern Portuguese rivers, the gill histopathological changes were qualitative and quantitatively analyzed and the lipid peroxidation and glutathione-S-transferase activity were determined. A multivariate statistical analysis was performed to establish correlations between these biological responses, environmental variables and ecological status. The quantitative evaluation of the main histopathological changes and oxidative stress responses emphasize the differences, among species, in the responses to the presence of contaminants in water. Discriminant canonical analysis showed that filament epithelium proliferation, necrosis and GST activity were the main contributors to discriminate the ecological status classification. In addition, the results showed that a wide range of environmental factors are influencing fish physiology. In conclusion, the gill biological responses, although not reflecting specific contaminants, can be used as biomarkers of ecosystems perturbation.

Effect of the hydrostatic pressure on otolith growth of early juveniles of Nile tilapia Oreochromis niloticus.

Nile tilapia Oreochromis niloticus early juveniles were maintained for 2 weeks in a pressurized system under a controlled photoperiod, at constant salinity and temperature. Groups of fish were exposed to one of three absolute hydrostatic pressure (HP) regimes: (1) a constant normal atmospheric pressure (100 kPa), (2) a constant 40 m pressure (500 kPa) or (3) a semi-diurnal cyclic vertical migration (100-500 kPa). No significant differences were detected in otolith size and incremental periodicity among the three HP treatments, suggesting that HP does not affect otolith growth of early juveniles O. niloticus.

Disruption of zebrafish (Danio rerio) embryonic development after full life-cycle parental exposure to low levels of ethinylestradiol.

Exposure of fish to the synthetic estrogen ethinylestradiol (EE2) has been shown to induce a large set of deleterious effects. In addition to the negative impact of EE2 in reproductive endpoints, concern has recently increased on the potential effects of EE2 in fish embryonic development. Therefore, the present study aimed at examining the effects of EE2 on the full embryonic development of zebrafish in order to identify the actual phases where EE2 disrupts this process. Hence, zebrafish were exposed to environmentally relevant low levels of EE2, 0.5, 1 and 2ng/L (actual concentrations of 0.19, 0.24 and 1ng/L, respectively) from egg up to eight months of age (F(1)), and the survival as well as the occurrence of abnormalities in their offsprings (F(2)), per stage of embryonic development, was investigated. A thorough evaluation of reproductive endpoints and transcription of vtg1 gene in the parental generation (F(1)) at adulthood, was performed. No significant differences could be observed for the two lowest EE2 treatments, in comparison with controls, whereas vtg1 transcripts were significantly elevated (40-fold) in the 2ng/L EE2 treatment. In contrast to the findings in the F(1) generation,a significant concentration-dependent increase in egg mortality between 8 and 24hours post-fertilization (hpf) was observed for all EE2 treatments, when compared with controls. The screening of egg and embryo development showed a significant increase in the percentage of abnormalities at 8 hpf for the highest EE2 concentration, a fact that might explain the increased embryo mortality at the 24 hpf time-point observation. Taken together, these findings indicate that the two lowest tested EE2 concentations impact late gastrulation and/or early organogenesis, whereas exposure to 2ng/L EE2 also disrupts development in the blastula phase. After early organogenesis has been completed (24 hpf), no further mortality was observed. These results show that increased embryo mortality occurs at EE2 levels below those inducing reproductive impairment and vtg1 gene induction in the male parental generation, thus suggesting that EE2 may impact some fish populations at levels below those inducing an increase in vtg1 transcripts. Hence, these findings have important implications for environmental risk assessment, strongly supporting the inclusion of embryonic development studies in the screening of endocrine disruption in wild fish populations.

Tilapia larvae Aroclor 1254 exposure: effects on gonads and circulating thyroid hormones during adulthood.

Aroclor 1254 a polychlorinated biphenyls (PCBs) mixture, when administrated through the diet, was previously found to inhibit adult tilapia (Oreochromis niloticus) reproduction. Since fish larvae can be more sensitive to contaminants, the objectives of this study were to evaluate in adults the impact in gonad development and in thyroid function of Aroclor 1254 administrated at larvae stages. Aroclor 1254 exposed tilapia presented both ovary and testicular alterations and a decline in T4 plasma concentration while T3 remained unaltered. This work shows exposure to Aroclor 1254 during tilapia early life stages causes a disruption of the reproductive axis that enables reproduction.

Raynaud's phenomenon in systemic lupus erythematosus.

OBJECTIVE: To determine the frequency and nature of clinical manifestations in Brazilian patients with systemic lupus erythematosus and Raynaud's phenomenon. METHODS: One hundred twenty-three patients with systemic lupus erythematosus (1982 American Rheumatism Association criteria) and Raynaud's phenomenon (at least two-phase, bilateral color reaction reported by the patient or observed by a physician) referred to the Rheumatology Unit of the Campinas University Hospital were retrospectively compared with 149 systemic lupus erythematosus patients without Raynaud's phenomenon. For each patient, gender, race, age at disease onset, disease duration, follow-up duration, clinical manifestations, and laboratory test findings were recorded. RESULTS: Patients with Raynaud's phenomenon were more likely to have skin lesions and/or myalgia/myopathy and less likely to have nephritis and nephrotic syndrome. All five patients with pulmonary hypertension also had Raynaud's phenomenon. Raynaud's phenomenon was less common in younger patients and more common in patients with alopecia. CONCLUSIONS: Raynaud's phenomenon was common in systemic lupus erythematosus patients from a tropical country. A better prognosis can be expected in lupus patients with Raynaud's phenomenon except when pulmonary hypertension occurs.

Systemic lupus erythematosus: clinical and laboratory aspects related to age at disease onset.

OBJECTIVE: To analyse the clinical and laboratory parameters in patients with SLE according to their age at disease onset a retrospective study was undertaken of 272 Brazilian patients fulfilling the 1982 ARA criteria for SLE who were referred to the University Hospital of Campinas between 1973-1992. METHODS: The patients were divided into three groups according to their age at disease onset: Group A: under the age of 16 (39 patients); Group B age 17 to 49 (223 patients); Group C over the age of 50 (10 patients). Various clinical and laboratorial parameters were analysed and compared among these groups. RESULTS: There were no significant differences in terms of race, time of disease onset or time of follow-up. Group A had more male patients than Groups B (p < 0.05) or C. Alopecia as an early manifestation, seizures and gastrointestinal involvement were more frequent in Group A (p < 0.05). Raynaud's phenomenon was lower in Group A than in Groups B and C (p < 0.05). Pericarditis was higher in Group C than in Groups A or B (p < 0.05). Nephrotic syndrome was lower in Group C than in Group A (p < 0.05). Positive LE cells were higher in Groups A and C than in Group B (p < 0.05). Anti-DNA antibodies were more prevalent in Group A than in B (p < 0.05). Anti-cardiolipin antibodies were more frequent in adult patients (p < 0.05) (Group B). The mortality rate was higher in Group A than in B or C (p < 0.05). CONCLUSION: The clinical presentation and course of SLE may be influenced by the age at disease onset. Younger patients showed a poorer prognosis with more seizures, gastrointestinal involvement, nephrotic syndrome, and a higher rate of mortality than the other groups. Group A included more male patients and also exhibited more positive LE cells and anti-DNA antibodies. Raynaud's phenomenon was lower in these young patients. Elderly patients (C) presented more pericarditis and showed mild disease.

Systemic lupus erythematosus in 18 Brazilian males: clinical and laboratory analysis.

The clinical and laboratory features of 18 males were compared with 254 female patients with systemic lupus erythematosus (SLE). At disease onset male patients were younger than female. Nephropathy, nephrotic syndrome and thrombocytopenia were significantly more frequent in male patients (p < 0.05). Pleuritis occurred as the initial symptom at a significantly higher frequency in males (p < 0.05). No significant immunological difference was found between two groups, except for anti-Sm antibodies which were more frequent in males than in females, but were measured in few patients. We concluded that male patients with SLE have a more severe disease, with higher morbidity, specially related to renal disease.