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Biomedical subjects

E Rocha

Publications and source records attributed to E Rocha.

At least 19 recordsLinked to original sources
PubMed2006

The effect of paraquat on hepatic EROD activity, liver, and gonadal histology in males and females of Nile tilapia, Oreochromis niloticus, exposed at different temperatures.

The activity of fish monooxygenases has been used as a monitoring tool to evaluate contamination by cytochrome P450 inducing agents. In this study ethoxyresorufin O-deethylase (EROD) activity was analyzed in males and females of Nile tilapia exposed to a low concentration of paraquat (PQ) at 17 degrees C and 27 degrees C. PQ-treated fish showed a high hepato-somatic index, except females acclimated at 17 degrees C. No differences were found for the gonado-somatic index (GSI) between males. However, PQ-treated females showed high GSI values (6.46+/-1.75) when compared with the control group (2.30+/-0.26) maintained at 27 degrees C. Males and females exposed to PQ showed higher microsomal protein values than the control group (9.46+/-0.22 vs. 6.20+/-0.18 at 17 degrees C; 9.51+/-0.35 vs. 4.70+/-0.19 mg of protein at 27 degrees C, in PQ-treated and control groups, respectively). The EROD activity was high in females exposed to PQ when compared with the control group at 17 degrees and 27 degrees C. The liver histology showed that PQ also caused some hepatic alterations of parenchyma, like vacuolization, necrosis, and an increase of macrophages aggregates and eosinophilic granular cells. Females exposed to PQ showed a greater increase of late-vitellogenic (22.2+/-3.2) and mature (12.1+/-2.0) percentage of oocytes than the control group (9.9+/-3.0 and 8.0+/-4.3, respectively), and a lower percentage of primary oocytes (8.0+/-3.3) at 27 degrees C. In short, this work has advanced new knowledge on the influence of gender in biotransformation activity and the reproductive activity of Nile tilapia exposed to a low concentration of paraquat, and demonstrated that their effects could be observed at different temperatures.

Animals↗
PubMed2006

Cutaneous transmissible venereal tumor without genital involvement in a prepubertal female dog.

An 11-month-old prepubertal crossbreed female dog was presented with multiple nodular lesions disseminated over the cervical, back, flank, and abdominal regions. The lesions were ulcerated and cauliflowerlike, or nodular and subcutaneous, measuring up to 13 cm in diameter. Cytologic preparations of one of the lesions revealed a uniform population of round to oval cells, with lightly basophilic cytoplasm that contained multiple distinct vacuoles. Frequent mitotic figures and occasional lymphocytes were also observed. The cytologic diagnosis was cutaneous transmissible venereal tumor (TVT) in a progressing growth phase. This was confirmed by histologic and immunohistochemical findings. Vaginal TVT was diagnosed later in the dog's mother. TVT is a contagious neoplasm of sexually mature dogs that usually is transmitted by coitus and affects the genital mucosa. To our knowledge, this is the first report of naturally occurring multicentric TVT in a prepubertal female dog and also is unique in its exclusively cutaneous (no mucosal) involvement. We speculate that transmission of neoplastic cells occurred during cohabitation and social/mothering behavior between the dogs. Despite the atypical clinical presentation, response to chemotherapy with vincristine was excellent, leading to complete regression of the neoplasm without relapse after 6 months.

Animals↗
PubMed2006

Cytochemical detection of calcium in a case of calcinosis circumscripta in a dog.

A 9-month-old intact female Serra-da-Estrela dog (giant Portuguese breed) was presented with a 2-month history of lingual lesions. Two hard, nodular, nonpainful lesions were observed on the lateral border of the tongue. Fine-needle aspiration yielded a chalky white material. Hemacolor-stained smears showed an amorphous granular basophilic background with crystal-like structures and granulomatous inflammation consisting of foamy macrophages and giant cells. Cytochemical staining with von Kossa and Alizarin red S confirmed the calcareous nature of the material. The cytologic diagnosis was lingual calcinosis circumscripta; this was later confirmed by histopathologic examination. To our knowledge, this case is the first to document the use of von Kossa and Alizarin red S on cytologic smears to obtain a definitive diagnosis of lingual calcinosis circumscripta.

Animals↗
PubMed2005

Postnatal cerebellar granule cells of the white rat (Rattus norvegicus): a quantitative study, using design-based stereology.

A stereological study was carried out on postnatal cerebellar granule cells of rats aged 6 and 10 days, for detecting whether and how much they would differ from those of young adult rats. The following parameters were estimated: number-weighted mean volume of the nucleus and of the soma; mean total surface area of the soma; mean absolute volumes per cell of total cytoplasm, mitochondria, Golgi apparatus, and cytosol; mean surface density of the rough endoplasmic reticulum (RER); mean total surface area of the RER. These values were compared between the two postnatal ages. In addition, those values were also analysed in comparison to the ones depicted in young adult rats (60 days), already published by our team, in order to detect similarities between them. It was noticed that, between 6 and 10 days, the mean surface density of the RER was the only parameter that did not change significantly. The comparison of each of the postnatal ages with 60 days revealed that, with the exception of the absolute volume of Golgi apparatus, significant differences were displayed concerning other organelles and cellular compartments. It was concluded that, although fine structural differences have been disclosed, from the stereological point of view postnatal granule cells at 10 days were practically similar to the young adult ones at 60 days. Some potential physiological implications have been considered.

Animals↗
PubMed2005

Activity of purine catabolism enzymes during the reproductive cycle of male and female brown trout (Salmo trutta).

In order to detect predicted changes in purine catabolism during the annual reproductive cycle of brown trout, we measured the activity of xanthine dehydrogenase, urate oxidase, and allantoinase. In kidney, only xanthine dehydrogenase was detected. In female liver and kidney, the activity of these enzymes was higher in May and decreased during vitellogenesis, with urate oxidase being undetectable in this period. In male liver, a similar variation pattern was found; however, in kidney, high activities were found in both May and December. These results suggest an influence of sex hormones in trout purine catabolism, especially in females.

Amidohydrolases↗
PubMed2004

A single prior course of BCNU-cisplatin chemotherapy has a significant deleterious effect on mobilization kinetics of otherwise untreated patients.

Extensive prior treatment with cytotoxic agents is associated with impaired mobilization of hematopoietic cells. To assess the effect of a single course of standard-dose chemotherapy (CT), we compared the results of filgrastim-induced mobilization among two sequential groups of grade III-IV malignant glioma patients included in a hematopoietic transplantation program. The first group (21 patients) had never been treated with CT until 2 days after surgery, when they received a course of 100 mg/m2 BCNU (i.v.) and 100 mg intracarotid cisplatin for cytoreduction (not for mobilization). At 1 month after this CT, they were mobilized with 12 microg/kg filgrastim. The second group (22 patients) was mobilized with the same dose of filgrastim directly after the surgery, without having ever received any prior CT. The blood level of CD34+ cells was significantly lower in the CT-treated patients, both on the fourth day of filgrastim (15 vs 36 cells x 10(6)/l; P=0.01) and on the fifth (25 vs 58 cells x 10(6)/l; P=0.003), as it was the number of CD34+ cells collected per apheresis (1.3 vs 3.5 x 10(6)/l; P<0.0005). The toxic effect of a single course of BCNU-cisplatin CT led to significant impairment of the filgrastim-induced mobilization response.

Adult↗
PubMed2004

Estimation of the number of stellate cells in a liver with the smooth fractionator.

To better evaluate the activation and proliferative response of hepatic stellate cells (HSC) in hepatic fibrosis, it is essential to have sound quantitative data in non-pathological conditions. Our aim was to obtain the first precise and unbiased estimate of the total number of HSC in the adult rat, by combining the optical fractionator, in a smooth sampling design, with immunocytochemistry against glial fibrillary acidic protein. Moreover, we wanted to verify whether there was sufficiently relevant specimen inhomogeneity that could jeopardize the high expected estimate precision when using the smooth fractionator design for HSC. Finally, we wanted to address the question of what sampling scheme would be advisable a priori for future studies. Microscopical observations and quantitative data provided no evidence for inhomogeneity of tissue distribution of HSC. Under this scenario, we implemented a baseline sampling strategy estimating the number (N) of HSC as 207E(06) (CV = 0.17). The coefficient of error [CE(N)] was 0.04, as calculated by two formerly proposed approaches. The biological difference among animals contributed congruent with 95% to the observed variability, whereas methodological variance comprised the remaining 5%. We then carried out a half reduction of sampling effort, at the level of both sections and fields. In either occasion, the CE(N) values were low ( congruent with 0.05) and the biological variance continued to be far more important than methodological variance. We concluded that our baseline sampling (counting 650-1000 cells/rat) would be appropriate to assess the lobular distribution and the N of HSC. However, if the latter is the only parameter to be estimated, around half of our baseline sampling (counting 250-600 cells/rat) would still generate precise estimates [CE(N) < 0.1], being in this case more efficient to reduce the number of sections than to reduce the sampled fields.

Animals↗
PubMed2004

Correlation between thrombus regression and recurrent venous thromboembolism. Examining venographic and clinical effects of low-molecular-weight heparins: a meta-analysis.

We analyzed the correlation between thrombus regression on control venography performed after discontinuation of heparin therapy and recurrent venous thromboembolism (VTE) detected during clinical follow-up in randomized trials comparing low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) in patients with deep vein thrombosis (DVT). Data were abstracted from MEDLINE, conference abstracts and reference lists of previous reviews. Randomized, controlled trials comparing LMWH and UFH for the treatment of DVT using a combined venographic and clinical assessment and with at least 2 months of follow-up were selected. The proportions of patients with thrombus regression on control venography performed soon after discontinuation of heparin therapy and recurrent VTE at 2-6 months were independently collected by two researchers. Thirteen studies met the inclusion criteria. There was a strong inverse correlation between thrombus regression and recurrent VTE (r =- 0.70; P =0.008). The venographic effect varied between the different LMWHs (P = 0.013). A very strong correlation was found when the results were pooled by the type of LMWH used (r = - 0.84; P=0.037). No influence of the dose interval used on the venographic effect (P=0.156) or on recurrent VTE (P=0.218) was shown. The lack of thrombus regression in venography, performed soon after heparin discontinuation, was correlated with clinical recurrence. Non-invasive imaging techniques should be relevant to identify non-responders and to assess the optimal duration of initial heparin treatment in daily clinical practice.

Heparin, Low-Molecular-Weight↗
PubMed2003

Effect of chronic stress on spatial memory in rats is attenuated by lithium treatment.

Stress is known to alter cognitive functions, such as memory, and it has been linked to the pathophysiology of mood and anxiety disorders. Chronic lithium treatment is used in some psychiatric disorders and has been suggested to act upon mechanisms which can enhance neuronal viability. The purpose of this work is to investigate a possible effect of lithium treatment in a chronic stress model. Adult male Wistar rats were divided in two groups, control and chronically stressed, treated either with normal chow or with chow containing LiCl for 40 days. Stress treatment was a chronic variable stress model, consisting of different stressors which were applied in a random fashion, once a day, every day. Memory was assessed by using the water maze task. The results demonstrated a marked decrease in reference memory in the water maze task in chronically stressed rats. This effect was attenuated by lithium treatment in all the parameters considered. No effect was observed in the working memory. These results indicate that lithium treatment may counteract some effects of chronic stress situations, particularly concerning spatial memory.

Animals↗
PubMed2003

A stereological study of medium antral follicles during the bovine estrous cycle.

Stereological methods were applied to bovine cumulus-oocyte complexes (COCs) in order to characterize them quantitatively during the estrous cycle. COCs from medium (4-8mm) antral follicles with a compact and complete cumulus mass, and with an uniform or a non-visible ooplasm were aspirated from ovaries of Holstein-Friesian cows, fixed in glutaraldehyde, randomly embedded in glycol-methacrylate, and sectioned at 20 microm. The unbiased nucleator principle was used for estimating the mean volumes of complexes, oocytes, cumulus cells, and nuclei of oocytes and cumulus cells. The thickness of the zona pellucida and the relative numerical percentages of the several morphological types (C1-C3) of cumulus cells were also evaluated. The optical disector procedure was used for cumulus cell sampling. Quantitative data show that COCs appear heterogeneous for all studied parameters. From metestrus to proestrus the volumes of COCs and oocytes remained constant, the volumes of oocytes and oocyte nuclei were correlated, the thickness of the outer zona pellucida decreased, and the relative numerical frequency of follicular type C3 cells increased. Results suggest that COCs from distinct estrus stages are structurally different, with type C3 follicular cells gradually differentiating from cell types C1 and C2.

Animals↗
PubMed2003

Stereological characterization of bovine (Bos taurus) cumulus-oocyte complexes aspirated from small antral follicles during the metestrous and proestrous phases.

Bovine cumulus-oocyte complexes (COCs) aspirated from slaughterhouse ovaries are used for in vitro maturation and fertilization after selection on the basis of morphological appearance of the cumulus and ooplasm. In this context, a quantitative characterization of COCs could provide additional criteria for selecting the most competent complexes. Bovine COCs from small (1-4mm) antral follicles were aspirated from metestrous and proestrous stage ovaries of Holstein-Friesian cows, fixed in glutaraldehyde, randomly embedded in glycol-methacrylate, and sectioned at 20 microm. The unbiased nucleator principle of stereology was used for estimating the mean volumes of complexes, oocytes, cumulus cells, and nuclei of oocytes and cumulus cells. The thickness of the zona pellucida and the relative numerical percentages of the several morphological types (C1, C2 and C3) of cumulus cells were also evaluated. The optical dissector procedure was used for cumulus cell sampling. Quantitative data show that the variability among complexes is generally high, especially for the volume of COCs. There were no linear correlations between the studied parameters, except between the volume of the oocyte and nucleus at metestrus. At proestrus, the volumes of COCs, oocytes and nuclei of oocytes, the volume of follicular cells and the thickness of the inner zona pellucida, were significantly higher than at metestrus. The relative numerical frequency of follicular type C1 cells was lower whereas that of type C3 cells was higher at proestrus than at metestrus. In conclusion, small antral follicles had larger COCs and oocytes at proestrus compared to metestrus and the COCs also had a higher percentage of follicular type C3 cells. Results suggest that for the same type of follicle size there may exist different functional populations of COCs at distinct stages of the bovine ovarian cycle.

Animals↗
PubMed2003

Efficacy and safety of bemiparin compared with enoxaparin in the prevention of venous thromboembolism after total knee arthroplasty: a randomized, double-blind clinical trial.

In this randomized, multicenter, controlled, double-blind, sequential trial, 381 patients undergoing primary total knee replacement were randomly assigned to receive subcutaneous injections of either 3500 IU anti-factor Xa of bemiparin sodium, first dose 6 h after surgery, or 40 mg of enoxaparin, first dose 12 h before surgery, followed by daily doses for 10 +/- 2 days, for the prophylaxis of venous thromboembolism. The primary efficacy endpoint was venous thromboembolism up to postoperative day 10 +/- 2, defined as deep vein thrombosis detected by mandatory bilateral venography, documented symptomatic deep vein thrombosis and/or documented symptomatic pulmonary embolism. The primary safety endpoint was major bleeding. Eighty-seven percent of all randomized patients (333 of 381 patients) were evaluable for efficacy. The incidence of venous thromboembolism was 32.1% (53 of 165 patients) in the bemiparin group and 36.9% (62 of 168 patients) in the enoxaparin group. The absolute risk difference was 4.8% in favor of bemiparin [95% confidence interval (CI), -15.1% to 5.6%; non-inferiority P-value: 0.02; superiority P-value: 0.36]. The incidence of proximal deep vein thrombosis was 1.8% (three of 165 patients) in the bemiparin group and 4.2% (seven of 168 patients) in the enoxaparin group. Major bleeding occurred in six patients (three in each group). There were no deaths during the study. This trial shows that bemiparin started postoperatively is as effective and safe as enoxaparin started preoperatively in the prevention of venous thromboembolism in patients undergoing total knee replacement.

Aged↗
PubMed2002

ATP stimulates human placental 11beta-hydroxysteroid dehydrogenase type 2 activity by a novel mechanism independent of phosphorylation.

The human placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) is believed to play a key role in fetal development since this enzyme protects the fetus from exposure to high levels of maternal cortisol by virtue of converting maternal cortisol to its inert metabolite cortisone. The present study was undertaken to examine the effect of ATP on 11beta-HSD2 activity in human placental microsomes. Enzyme activity, reflected by the rate of conversion of cortisol to cortisone, was stimulated more than six-fold by 0.5 mM ATP (EC(50) = 0.2 mM). Such stimulation appears to be mediated through a novel mechanism independent of ATP-induced phosphorylation of the reaction components since AMP-PNP, a non-hydrolyzable analogue of ATP, was equally effective. The ATP-induced stimulation of 11beta-HSD2 activity is adenine nucleotide specific in that a similar stimulation was observed with ADP and AMP but not with CTP, GTP, or UTP. Furthermore, ATP increased the maximal velocity (V(max)) of the 11beta-HSD2 catalyzed conversion of cortisol to cortisone without altering the apparent K(m) of 11beta-HSD2 for cortisol, suggesting that ATP may stimulate enzyme activity by interacting with the enzyme at a site other than that involved in substrate binding. In conclusion, the present study has identified ATP as a novel regulator of human placental 11beta-HSD2 in vitro. It is conceivable that intracellular ATP may have a profound effect on 11beta-HSD2 function in vivo.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed2001

An investigation of the neuroprotective effect of lithium in organotypic slice cultures of rat hippocampus exposed to oxygen and glucose deprivation.

Brain ischemia results in cellular degeneration and loss of function. Here we investigated the neuroprotective effect of lithium in an in vitro model of ischemia. Organotypic hippocampal slice cultures were exposed to oxygen and glucose deprivation. Cellular death was quantified by measuring uptake of propidium iodide (PI). Lithium chloride (0.2-1.2 mM) was added to the medium before, during and after lesion induction. A decrease in incorporation of PI was observed, indicating a neuroprotective effect in all doses tested. We also studied the effect of lithium on the phosphorylation of HSP27, a heat shock protein involved in cellular protection in its dephosphorylated state. In the lesioned hippocampus, 0.4 mM lithium chloride decreased the proportion of phosphorylated HSP27 to total HSP27. These results suggest that lithium may be useful in the treatment of brain ischemia.

Animals↗