Search

Heavy metals are becoming ubiquitous in our environment due to its natural abundance and anthropogenic uses. Arsenic an example of heavy metal, can cause deleterious effects in numerous organs and biochemical pathways. Use of noninvasive testing procedures had been used in diagnosis, monitoring of pathological events during treatment. In order to investigate the effects of sodium selenite on biomarkers of organ injury in arsenic-exposed rats for a period of 5 weeks, twenty-four male albino rats divided into four groups (n = 6) were exposed to sodium arsenite (SA) and sodium selenite (SS). Group I (control) received only distilled water, groups II and III were exposed to 40 ppm SA in drinking water ad libtum, in addition group III received 0.25 mg/kg bwt SS orally and group IV received 0.25 mg/kg bwt SS orally only. Activities and levels of organ-injury markers were determined in the blood using spectrophotometric method. In the SA exposed group (group II), there were significant increases (p ˂ 0.05) in the activities of plasma xanthine oxidase, lactate dehydrogenase, aldolase, glutamate dehydrogenase, NAD glycohydrolase, aspartate and alanine aminotransferases, and levels of plasma nitric oxide and hydrogen sulphide (in plasma and erythrocyte) when compared to control. Sodium selenite administration abrogated the observed effects of SA exposure by decreasing the measured biomarkers to the normal level as observed in group III and IV. In conclusion, this results suggests the use of SS is safe and non-invasive approach for the prevention of SA-induced toxicity in humans.

The targeted pathogen-selective approach to drug development holds promise to minimize collateral damage to the beneficial microbiome. The AB₅-topology pertussis toxin (PtxS1-S5) is a major virulence factor of Bordetella pertussis, the causative agent of the highly contagious respiratory disease whooping cough. Once internalized into the host cell, PtxS1 ADP-ribosylates α-subunits of the heterotrimeric Gαi-superfamily, thereby disrupting G-protein-coupled receptor signaling. Here, we report the discovery of the first small molecules inhibiting the ADP-ribosyltransferase activity of pertussis toxin. We developed protocols to purify milligram-levels of active recombinant B. pertussis PtxS1 from Escherichia coli and an in vitro high throughput-compatible assay to quantify NAD⁺ consumption during PtxS1-catalyzed ADP-ribosylation of Gαi. Two inhibitory compounds (NSC228155 and NSC29193) with low micromolar IC₅₀-values (3.0 μM and 6.8 μM) were identified in the in vitro NAD⁺ consumption assay that also were potent in an independent in vitro assay monitoring conjugation of ADP-ribose to Gαi. Docking and molecular dynamics simulations identified plausible binding poses of NSC228155 and in particular of NSC29193, most likely owing to the rigidity of the latter ligand, at the NAD⁺-binding pocket of PtxS1. NSC228155 inhibited the pertussis AB₅ holotoxin-catalyzed ADP-ribosylation of Gαi in living human cells with a low micromolar IC₅₀-value (2.4 μM). NSC228155 and NSC29193 might prove to be useful hit compounds in targeted B. pertussis-selective drug development.

New earthquake risk maps, based on the Cornell‐McGuire methodology, have been prepared for the Australian continent and continental margins. The risk is depicted as contours of peak ground velocity, acceleration and ground intensity with a 10% probability of being exceeded in 50 years. The earthquake process was assumed to be Poissonian and consequently foreshocks and aftershocks were eliminated. The estimated maximum earthquake magnitude likely to be expected in each zone was assumed to be half a magnitude unit greater than the largest recorded Richter magnitude for that zone. For areas outside the defined source zones, normalized background seismicity levels were used in the risk estimates. Separate relationships for the attenuation of ground intensity with hypocentral distance using a scaling law of the Kanai form were obtained for western, southeastern and northeastern Australia and for Indonesian earthquakes felt in northern Australia. These were based on the determination of mean isoseismal radii fr...

During a 39-day microearthquake survey in the Sulphur Springs geothermal region, St. Lucia, seven local hypocenters were determined. Emergent P onsets and missing S-waves were observed for five of these, and attenuated S-waves recorded for two regional events. These imply the presence of at least two significant fluid bodies beneath the area. Ground noise measurements near natural steam vents suggest a deep source for the steam.

During the period January 1972–June 1974, Mt Ngauruhoe, an andesitic volcano in the Central North Island of New Zealand, has had 12 main eruptive periods. The fortnightly component of the earth tide is strongly correlated with these eruptive periods. Seven start within 1.5 days of a tidal maximum. The distribution of the date of commencement of these eruptive periods about the maximum of the earth tide is skewed; more eruptions occur before the maximum than after it. Only one eruptive period occurs within 1.5 days of a tidal minimum. The triggering near the time of the tidal maximum may result from the enhanced effects of tidal compression and expansion of the earth's crust on magma beneath the volcano. Compression would cause the magma to rise in the conduit; expansion would promote degassing.