Modelling the risk of mortality of Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae) exposed to different turbidity conditions.

The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774), the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU). This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil) and Mogi Guaçu (Porto Ferreira-SP-Brazil) during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU), for periods longer than 120 hours, may be considered a probable cause of mortality for the species.

Antilisterial activity of lactic acid bacteria inoculated on cooked ham.

This study was conducted to evaluate the ability of Lactobacillus sakei 1, a bacteriocin-producing (bac(+)) lactic acid bacterium (LAB), isolated from Brazilian fresh pork sausage to inhibit two Listeria monocytogenes strains (serotypes 4b and 1/2a) on cooked, sliced vacuum-packaged ham. L. sakei ATCC 15521 was used as a non-bacteriocin producer (bac(-)). L. monocytogenes (ca. 2 logCFU/mL) and LAB (ca. 6 logCFU/ml) were inoculated on the sterilized ham, vacuum-sealed and incubated at 8°C for 10 days. A treatment with the bacteriocin Chrisin (UI/ml) was included. Both L. monocytogenes strains were significantly inhibited in the presence of either bac(+) and bac(-) LAB in comparison to the control (L. monocytogenes alone). Using a bacteriocinogenic strain of LAB did not offer an additional barrier to listerial growth in the studied meat system. The application of Chrisin did not affect at all the growth of L. monocytogenes.

A simple protocol for the routine calibration of pH meters

Um protocolo laboratorial simples para calibração de peagâmetros é descrito e testado, baseado no uso de soluções de padrões primários:biftalato de potássio e Bórax (tetraborato de sódio decaidratado), de concentração e pH exatos e conhecidos.As soluções se conservam bem à temperatura ambiente, por tempo prolongado, sem necessidade de refrigeração.A calibração pode ser conferida usando soluções padrão de dihidrogeno fosfato de sódio, de carbonato de sódio, de benzoato de sódio, de salicilato de sódio ou de oxalato de potássio. Métodos para purificação de Bórax e de cloreto de potássio são descritos, bem como é sugerido um novo método de neutralização de solução de cloreto de sódio 0,9 por cento

Effect of oral selenium administration on cisplatin-induced nephrotoxicity in rats.

Cis -diamminedichloroplatinum(II) (CP), an important antineoplasic drug, shows remarkable toxicity to the kidney. Methods to reduce CP nephrotoxicity include the use of sodium selenite. The aim of the present study was to investigate the interaction between orally administered selenium and CP in the rat. After observing the effects of CP on body growth rate, urinary volume, serum creatinine, serum selenium levels, creatinine clearance, renal malondialdehyde, and glutathione levels, as well as on renal light microscopically visible lesions, the effects of the sodium selenite administration by gavage of 2 mg per kg of body wt. 24 h and 1 h prior to a single CP intraperitoneal injection of 5 mg per kg of body wt. followed by its daily administration for the 7 subsequent days on these parameters, were examined. CP increased renal malondialdehyde, renal glutathione, and serum creatinine and decreased creatinine clearance. Lipid peroxidation is one of the mechanisms by which CP induces renal damage. Selenium treatment decreased the effect of CP on serum creatinine, and renal malondialdehyde levels, but did not affect the other parameters with the exception of kidney necrosis which was also diminished by this treatment.

[Occupational risk of acquiring tuberculosis among hospital nursing personnel]. / Risco ocupacional de adquirir tuberculose entre trabalhadores de enfermagem hospitalar.

At hospitals, patients with tuberculosis are attended by several professionals and among them nursing workers. These workers are subjected to the risk of the tuberculosis infection. This study had the objective of investigating the number of nursing workers in a hospital that acquired tuberculosis in a pre-determined period and their general characteristics; to calculate the morbidity coefficient of this disease and discuss the occupational risk among these workers. In one year, health workers presented 3.86 times greater risk, and, in another year, 1.47 times greater risk. In the present study tuberculosis was considered an occupational hazard for hospital nursing workers.

Oral administration of sodium selenite minimizes cisplatin toxicity on proximal tubules of rats.

Cisplatin (c-DDP) is a widely used antineoplastic drug whose main side effect is nephrotoxicity. Selenium, administered intravenously or intraperitoneally, has been shown to provided protection against c-DDP-induced nephrotoxicity in rats. In the present study, the protective effect of orally administered sodium selenite on c-DDP toxicity was further examined. Animals treated with c-DDP alone showed increased urinary volume, decreased creatinine clearance (GFR), and a rise in urinary N-acetyl-(beta-D-glucosaminidase) (NAG) isoenzyme B activity. When sodium selenite was given prior to c-DDP, rats showed less GFR decline, delayed urinary volume increases, and no urinary NAG isoenzyme B activity increment. It is suggested that a single oral dose of sodium selenite given prior to c-DDP administration, although not preventing deterioration of renal function, partially protects rats from early proximal tubular injury.

Inhibition of the lethal and myotoxic activities of Crotalus durissus terrificus venom by Tabernaemontana catharinensis: identification of one of the active components.

In Brazilian folk medicine, victims of bites by poisonous animals are usually treated with plant extracts derived from the diverse national flora. The chemical and pharmacological properties of most extracts were yet not investigated. In the rural community of Assis-SP, the root bark of Tabernaemontana catharinensis ("leiteiro", "cow milk") is applied to the site of the snake bite and believed to neutralize the effect of the venom. We report here the ability of the lyophilized aqueous extract (AE) and of a pure compound obtained from the ethanolic extract of T. catharinensis to inhibit the lethal and myotoxic activities of C. d. terrificus (South American rattlesnake) venom. Doses of 10 mg AE/100 g, injected (i.m., rat) 20 s after injecting (i.m.) the venom and that of 2.5 mg AE/100 g, incubated for 1 h at 25 degrees C with the venom before injection (i.m.) were able to neutralize the lethal activity of 2LD50. These data indicate that T. catharinensis could be used as a source of a model molecule able to neutralize the lethality and myotoxicity induced by C. d. terrificus venom. Its ethanolic extract was then fractionated on a silica gel 60 chromatography column affording fractions A to F. Fraction A consisted basically of non-polar compounds, terpenes and sterols. Fraction D showed a pronounced antiophidian activity which was later correlated with the presence of the quaternary alkaloid 12-methoxy-4-methylvoachalotine in this fraction. This alkaloid was isolated and inhibited 100% lethality when injected 20 s after 2 LD50 at 1.7 mg/100 g.

[Chemical substances, work and neurologic changes: possible relationships between those variables]. / Substâncias químicas, trabalho e alterações neurológicas: possíveis relações entre estas variáveis.

Authors searched 239 reports of patients admitted in a hospital who carried neurological pathologies with unknown etiologies in order to find the possible relationship between the disease and the occupational use of chemical substances. They found the occupation in 32 reports. 37.50% of the patients worked with agriculture; 34.37% were maids/worked at home; 12.50% were masons; one was a shoemaker, one a saddler; one made furniture and the others worked with machines. Considering their activities, they possibly used chemical substances. Few information relating this utilization and the presented disease showed the reduced importance given to these variables.

Clinical effectiveness of lidocaine and benzocaine for topical anesthesia.

The effectiveness of lidocaine and benzocaine in reducing pain produced by needle insertion into the palate was evaluated in a double-blind and placebo-controlled study using a more suitable method. Twenty subjects, 10 men and 10 women, submitted to 4 sessions in which they were randomly treated with 5% lidocaine, a placebo that tasted like lidocaine, 20% benzocaine, and a placebo that tasted like benzocaine. At each session, a 27-gauge needle was inserted into the palate twice, once before (baseline) and once after drug application for 1 minute. Immediately after each insertion, subjects indicated on a visual analog scale the pain intensity perceived. Lidocaine and benzocaine were equally efficient, and both were better than placebo in reducing pain caused by insertion of needles into the palate.

Radiographic contrast. A comparative study of three dental X-ray films.

OBJECTIVE: To investigate the radiographic contrast of three dental X-ray films (Ultra-speed, Ektaspeed and Ektaspeed Plus, Eastman-Kodak, Rochester, NY, USA). METHODS: An aluminium stepwedge was radiographed for the objective assessment and a dried human mandibular segment including the teeth for the subjective evaluation. In the objective assessment, contrast was evaluated from the measured optic densities and the results analysed statistically by the Kruskal-Wallis one-way Anova and Mann-Whitney U test. Subjective evaluation was performed by 12 dentists with a range of clinical experience and scores were assigned to five dental and bony structures. RESULTS: In the objective evaluation there was no significant difference in contrast obtained with the Ultra-speed and Ektaspeed Plus films: both had significantly better contrast than Ektaspeed film. The subjective assessment revealed that the majority of the dentists preferred either Ultra-speed or Ektaspeed Plus films for contrast. CONCLUSION: Radiographic contrast of Ektaspeed Plus did not differ significantly from Ultra-speed and both were superior to Ektaspeed film.