Towards the mechanism and comparative effect of diphenyl diselenide, diphenyl ditelluride and ebselen under various pathophysiological conditions in rat's kidney preparation

As an extension of our previous work we not only evaluated the relationship between acidosis and lipid peroxidation in rat's kidney homogenate, but also determined for the first time the potential anti-oxidant activity of diphenyl diselenide, diphenyl ditelluride and ebselen at a range of pH values (7.4–5.4). Because of the pH dependency of iron redox cycling, pH and iron need to be well controlled and for the reason we tested a number of pH values (from 7.4 to 5.4) to get a closer idea about the role of iron under various pathological conditions. Acidosis increased rate of lipid peroxidation in the absence Fe (II) in kidney homogenates especially at pH 5.4. This higher extent of lipid peroxidation can be explained by; the mobilized iron which may come from reserves where it is weakly bound. Addition of iron (Fe) chelator desferoxamine (DFO) to reaction medium completely inhibited the peroxidation processes at all studied pH values including acidic values (5.8–5.4). In the presence of Fe (II) acidosis also enhanced detrimental effect of Fe (II) especially at pH (6.4–5.4). Diphenyl diselenide significantly protected lipid peroxidation at all studied pH values, while ebselen offered only a small statistically non-significant protection. The highest anti-oxidant potency was observed for diphenyl ditelluride. These differences in potencies were explained by the mode of action of these compounds using their catalytic anti-oxidant cycles. However, changing the pH of the reaction medium did not alter the anti-oxidant activity of the tested compounds. This study provides evidence for acidosis catalyzed oxidative stress in kidney homogenate and for the first time anti-oxidant potential of diphenyl diselenide and diphenyl ditelluride not only at physiological pH but also at a range of acidic values.     

Postoperative Deep Vein Thrombosis in Sudanese Patients

The incidence of postoperative deep vein thrombosis diagnosed by radioisotope scanning in 100 Sudanese patients aged 40 or over was 12%. This compares with an incidence of nearly 30% in 542 patients reported from British hospitals using the same diagnostic technique. The reason for the difference is obscure and needs further investigation.     

Mathematical analysis of the stimulus for the lateral line organ

Behavioral studies have shown that a blind fish is capable of detecting and recognizing stationary objects in its surroundings. It is proposed that the displacement of water caused by the fish as it moves is the basis for this detection capability. Alterations in the displacement of water around the fish, caused by the obstacle, act as stimuli for the lateral line organ. The question of how these stimuli acting on the skin of the fish, image the environment and what information is thus made available to the fish is the concern of this paper. The stimuli for the lateral line organ are derived mathematically. Two cases are treated: that of a fish gliding past an obstacle and that of one approaching an obstacle.     

Acacia ochracea (Leguminosae-Mimosoideae), a new species from Somalia

Acacia ochracea , a new species in the A. Senegal complex, is described and illustrated. It is a common and conspicuous tree over large areas in the western Bay Region and in the Gedo Region in SW Somalia.     

Superoxide dismutase protects against paraquat-mediated dioxygen toxicity and mutagenicity: studies in Salmonella typhimurium

Paraquat is univalently reduced to the relatively stable, but oxygen-sensitive, paraquat radical (PQ.+). This PQ.+ can react with dioxygen to generate the superoxide radical, which can further generate other more deleterious species of oxygen free radicals (i.e., hydroxyl radical, OH.). These oxygen free radicals are known to cause chromosomal breaks; therefore, it was logical to postulate that paraquat is a mutagen. This proved to be the case when tested in a modified Ames test using a liquid incubation assay. Salmonella typhimurium strains TA98 and TA100 were grown in the presence of various concentrations of PQ, as well as in the presence of known mutagenic compounds: mitomycin C, azide, and proflavine. Paraquat was much more toxic and mutagenic in a simple nutritionally restricted medium than in a rich complex medium and these toxic and mutagenic effects were oxygen dependent. Furthermore, cells containing high levels of superoxide dismutase were more resistant to the toxic and mutagenic effects of paraquat than were cells containing a normal level of this enzyme.     

Southeast Asian Mitochondrial DNA Analysis Reveals Genetic Continuity of Ancient Mongoloid Migrations

Human mitochondrial DNAs (mtDNAs) from 153 independent samples encompassing seven Asian populations were surveyed for sequence variation using the polymerase chain reaction (PCR), restriction endonuclease analysis and oligonucleotide hybridization. All Asian populations were found to share two ancient AluI/DdeI polymorphisms at nps 10394 and 10397 and to be genetically similar indicating that they share a common ancestry. The greatest mtDNA diversity and the highest frequency of mtDNAs with HpaI/HincII morph 1 were observed in the Vietnamese suggesting a Southern Mongoloid origin of Asians. Remnants of the founding populations of Papua New Guinea (PNG) were found in Malaysia, and a marked frequency cline for the COII/tRNA(Lys) intergenic deletion was observed along coastal Asia. Phylogenetic analysis indicates that both insertion and deletion mutations in the COII/tRNA(Lys) region have occurred more than once.     

Effect of papaya (Carica papaya) leaf extract as dietary growth promoter supplement in red hybrid tilapia (Oreochromis mossambicus × Oreochromis niloticus) diet

The purpose of this experiment was to examine the potential use of Carica papaya leaf extract as a supplement to promote growth and improve feed utilization in red hybrid tilapia. Five diets were formulated containing isolipidic (80 g/kg) and isonitrogenic (350 g/kg) levels. All feeds contained similar types and amounts of raw materials but differed in the inclusion of papaya leaf extract (0, 5, 10, 20 and 40 g/kg feed). The initial size of fish used was 2.3 ± 0.01 g. Each diet was performed in triplicate tanks, and the feeding period was 12 weeks. Fish fed diet containing 2% papaya leaf extract (PLE) had the highest final weight, 31.14 ± 1.47 g, followed by 1% PLE (27.27 ± 1.75 g). These two diets (1% and 2%) were also showed significant improvements of weight gain, SGR, and feed efficiency of the red hybrid tilapia (p < 0.05). However, papaya leaf extract did not affect the HSI, VSI, PER, digestive enzymes activity, blood composition, and survival rate. Supplementing the diets with papaya leaf extract lowered serum urea. Findings of this research suggest that adding papaya leaf extract to the diet of red hybrid tilapia improves growth and feed efficiency without adversely affecting blood parameters. Therefore, an inclusion level between 1% and 2% of the papaya leaf extract is recommended as a feed additive to promote red hybrid tilapia fry growth.