Endoparasite community of anurans from an altitudinal rainforest enclave in a Brazilian semiarid area.

In the present study, we aimed to describe the composition of endoparasites associated with anurans from an altitudinal rainforest enclave in northeastern Brazil. Additionally, we tested if microhabitat use influences endoparasite abundance and richness, as well as the hypothesis that larger frogs tend to be more parasitized. We sampled 306 individuals from 25 anuran species that were necropsied and analysed using a stereomicroscope. The total endoparasite prevalence was 79.08%, with a parasitic community consisting of 46 taxa. Overall, we found the common pattern described for Neotropical amphibians, which is the predominance of generalist and direct-cycle parasites. Twenty new host records and two possible new parasite species were found, highlighting the importance of this type of inventory. We also observed that microhabitat use was associated with a significant difference in parasite richness between groups, in which arboreal and terrestrial species, and aquatic and arboreal species contributed to these differences. Moreover, larger frogs tended to be more parasitized regarding only an interspecific view. Our results suggest that parasite richness is directly related to infection cycle and how the host exploits its habitat.

Quercetin ameliorates polychlorinated biphenyls-induced testicular DNA damage in rats.

Polychlorinated biphenyls (PCBs) are a group of environmental contaminants widely reported to cause gonadal toxicity in both humans and animals. This study investigated the amelioratory role of quercetin in PCBs-induced DNA damage in male Wistar rats. Polychlorinated biphenyls were administered intraperitoneally at a dose of 2 mg kg(-1) alone or in combination with quercetin (orally) at 50 mg kg(-1) for 25 days. Quercetin modulation of PCBs-induced gonadal toxicity was evaluated using selected oxidative stress indices, comet assay, measurement of DNA concentration and histology of the testes. Administration of PCBs alone caused a significant (P < 0.05) depletion in the total thiol level in testes of treated rats. Conversely, the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) production were markedly elevated in testes of PCBs-treated rats compared with control. Further, PCBs exposure produced statistically significant increases in DNA tail migration, degraded double-stranded DNA (dsDNA) concentration and histological alterations of testes of the treated rats compared to control. Quercetin cotreatment significantly improved the testicular antioxidant status, decreased DNA fragmentation and restored the testicular histology, thus demonstrating the protective effect of quercetin in PCBs-treated rats.

Protective effects of the angiotensin type 1 receptor antagonist losartan in infection-induced and arthritis-associated alveolar bone loss.

BACKGROUND AND OBJECTIVE: The angiotensin type 1 (AT1) receptor has been implicated in the pathogenesis of inflammatory bone disorders. This study aimed to investigate the effect of an AT1 receptor antagonist in infection-induced and arthritis-associated alveolar bone loss in mice. MATERIAL AND METHODS: Mice were subjected to Aggregatibacter actinomycetemcomitans oral infection or antigen-induced arthritis and treated daily with 10 mg/kg of the prototype AT1 antagonist, losartan. Treatment was conducted for 30 d in the infectious condition and for 17 d and 11 d in the preventive or therapeutic regimens in the arthritic model, respectively. The mice were then killed, and the maxillae, serum and knee joints were collected for histomorphometric and immunoenzymatic assays. In vitro osteoclast assays were performed using RAW 264.7 cells stimulated with A. actinomycetemcomitans lipopolysacharide (LPS). RESULTS: Arthritis and A. actinomycetemcomitans infection triggered significant alveolar bone loss in mice and increased the levels of myeloperoxidase and of TRAP(+) osteoclasts in periodontal tissues. Losartan abolished such a phenotype, as well as the arthritis joint inflammation. Both arthritis and A. actinomycetemcomitans conditions were associated with the release of tumor necrosis factor alpha (TNF-α), interferon-gamma, interleukin-17 and chemokine (C-X-C motif) ligand 1 and an increased RANKL/osteoprotegerin ratio in periodontal tissues, but such expression decreased after losartan treatment, except for TNF-α. The therapeutic approach was as beneficial as the preventive one. In vitro, losartan prevented LPS-induced osteoclast differentiation and activity. CONCLUSION: The blockade of AT1 receptor exerts anti-inflammatory and anti-osteoclastic effects, thus protecting periodontal tissues in distinct pathophysiological conditions of alveolar bone loss.

A comparison between transport and diffusion calculations using a finite element-spherical harmonics radiation transport method.

Most researchers choose the diffusion approximation to the transport equation as the model to describe photon migration in biological tissues. However, the applicability of this approximation is limited and, in certain cases, invalid. In this paper we introduce a two-dimensional, finite element-spherical harmonics (FE-P(N)) radiation transport method for the simulation of light propagation in tissue. The propagation of light is investigated first in a layered cylinder, which can be seen as a very simplistic approximation of a human head. Effects of the anisotropy factor g on the photon migration is then examined in homogeneous and heterogeneous media for different values of g and mu(s). The influence of void-like heterogeneities and channels in which absorption and scattering are very small compared with the surrounding medium on the transport of photons is also investigated. Significant differences between transport and diffusion calculations are shown to occur in all cases.

Chaotic versus random ionization.

We use Kepler maps to study the classical ionization of the hydrogen atom driven by electric fields; we compare the ionization rate (IR) due to chaotic motion (constant field amplitude) with the IR due to randomness (random field amplitude). We find that for weak fields the ionization due to random amplitude is more effective, while for strong fields the ionization due to chaos is more effective; so, there is a cross of such ionization curves. A physical explanation of this phenomenon, based on the trajectory behavior, is given.

[Osteoblastoma: analysis of the treatment of 24 cases]. / Osteoblastoma: análise do tratamento de 24 casos.

The authors study 24 patients with the histologic diagnosis of osteoblastoma treated from 1953 to 1996, with a mean follow-up of 33.4 months. Two were considered as a malignant osteoblastoma. Twenty-two cases were operated, and in 2 of these was performed only a selective embolization to pelvic and spine localization. It was discussed clinical and radiographic aspects and the response to treatment. It was obtained 20 good and 4 poor results.

Apoptosis as a mechanism of cell death induced by different chemotherapeutic drugs in human leukemic T-lymphocytes.

The involvement of apoptosis in the mechanism of cell death induced by six clinically relevant anticancer drugs [methotrexate (MTX), doxorubicin (ADR), daunorubicin (DNR), vincristine (VCR), 6-mercaptopurine (6MP), and prednisolone (PRD)] in human leukemic T-lymphocytes (CCRF-CEM and Jurkat) was investigated by analysing changes in cell size and morphology, changes in membrane integrity, alterations in [Ca2+]i and induction of DNA fragmentation. MTX, ADR, and DNR showed pronounced dose- and time-dependent cytotoxic effects on both cell lines, whereas cell viability was not considerably reduced by 6MP or PRD. On the other hand, the cytotoxic activity of VCR was much higher on Jurkat cells than on CEM cells. With the exception of 6MP and PRD, all the other compounds induced extensive chromatin condensation, nuclear fragmentation, plasma membrane blebbing, and formation of apoptotic bodies and fragmentation of DNA in both cell lines. Occurrence of DNA fragmentation always preceded loss of membrane integrity. These observation are consistent with cell death being mediated by apoptosis. Significant increases in [Ca2+]i were only observed in CEM cells preincubated with MTX or DNR (10 microM). In contrast, MTX as well as VCR induced a reduction in the basal intracellular Ca2+ concentration in Jurkat T-cells. Although the ability to induce changes in [Ca2+]i correlated with higher cytotoxic potency of the anticancer drugs, a causal relationship between increased [Ca2+] and induction of apoptosis could not be clearly established. These results, therefore, suggest no determinant role for Ca2+ in triggering the process of endonucleolytic cleavage of genomic DNA in these leukemic T-lymphocytes.

[Frequency of intestinal helminth eggs in public restrooms in Sorocaba, SP]. / Estudo da freqüência de ovos de helmintos intestinais em sanitários de uso público de Sorocaba, SP.

Four hundred and five water closets were investigated: 11 located at public squares, 2 at the railroad station, 4 at the bus station, 55 at bars and restaurants, 146 at state schools, 116 at municipal schools, 8 at private schools, 36 at public health centers, 16 at sports centers, 8 at orphanages and 3 at shopping malls. Microscopy slides with adhesive tape were used. The material was obtained by sticking the tape onto the following elements: 4 spots on the toilet seat, internal and external door knobs, latch, faucet handle and discharge valve (push button or pulling string). Out of the 405 water closets studied, 22 (5.43%) were contaminated. Eggs of Ascaris lumbricoides, Ancylostomatidae, Enterobius vermiculares, Taenia sp and Hymenolepis nana were found. In 2 water closets eggs of 2 parasites were found simultaneously.

[Elevated CEA values after cystectomy for bladder cancer and intestinal urinary diversion not evidence of tumor recurrence]. / Erhöhte CEA-Werte nach Zystektomie wegen Harnblasenkarzinom und intestinaler Harnableitung nicht beweisend für Tumorrezidiv.

In the literature determination of carcino-embryonal antigen (CEA) in urine and plasma in bladder cancer patients reveals a positive rate between 40% and 80%. In the postoperative screening of radical cystectomized patients with intestinal urinary diversion high CEA levels gave primarily suspicion for tumor recurrence or metastases, however met-screenings were negative. In a prospective study 54 cystectomized bladder cancer patients with colonic conduit or ureterosigmoidoistomy were compared with cystectomized non-tumor-patients concerning the CEA levels in plasma and urine. Raised CEA-levels were obtained in more than 80% of the non-tumor-patients; urinary CEA was positive in 90% (m = greater than 2000 ng/ml), whereas only 3/5 patients with demonstrable tumor recurrence revealed raised CEA levels. The study shows significantly that determination of CEA in the postoperative screening care of bladder cancer patients with intestinal urinary diversion is not a useful tool in the armamentarium of tumor-screening.