Immunoexpression of aquaporins 1, 2, 3 and 4 in kidney of yak (Bos grunniens) on the Qinghai-Tibetan Plateau

Aquaporins (AQP) 1, 2, 3 and 4 belong to the aquaporin water channel family and play an important role in urine concentration by reabsorption of water from renal tubule fluid. Renal AQPs have not been reported in the yak (Bos grunniens), which resides in the Qinghai Tibetan Plateau. We investigated AQPs 1?4 expressions in the kidneys of Yak using immunohistochemical staining. AQP1 was expressed mainly in the basolateral and apical membranes of the proximal tubules and descending thin limb of the loop of Henle. AQP2 was detected in the apical plasma membranes of collecting ducts and distal convoluted tubules. AQP3 was located in the proximal tubule, distal tubule and collecting ducts. AQP4 was located in the collecting ducts, distal straight tubule, glomerular capillaries and peritubular capillaries. The expression pattern of AQPs 1?4 in kidney of yak was different from other species, which possibly is related to kidney function in a high altitude environment.     

Kinetics of the Anti-oxidant Response to Salinity in the Halophyte Cakile maritima

The effects of NaCl stress on the activity of anti-oxidant enzymes (superoxide dismutase, catalase (CAT),peroxidase (POD),ascorbate peroxidase (APX), monodehydroascorbate reductase, dehydroascorbate reductase (DHAR), and glutathionereductase (GR)), anti-oxidant molecules (ascorbate and glutathione), and parameters of oxidative stress (malondialdehyde(MDA), electrolyte leakage, and H_2O_2 concentrations) were investigated in Cakile maritima, a halophyte frequent along theTunisian seashore. Seedlings were grown in the presence of salt (100, 200, and 400 mmol/L NaCI). Plants were harvestedperiodically over 20 days. Growth was maximal in the presence of 0-100 mmol/L NaCl. At 400 mmol/L NaCl, growthdecreased significantly. The salt tolerance of C. maritima, at moderate salinities, was associated with the lowest values ofthe parameters indicative of oxidative stress, namely the highest activities of POD, CAT, APX, DHAR, and GR and high tissuecontent of ascorbate and glutathione. However, prolonged exposure to high salinity resulted in a decrease in anti-oxidantactivities and high MDA content, electrolyte leakage, and H_2O_2 concentrations. These results suggest that anti-oxidantsystems participate in the tolerance of C. maritima to moderate salinities.     

The Uni2 phosphoprotein is a cell cycle regulated component of the basal body maturation pathway in Chlamydomonas reinhardtii

Mutations in the UNI2 locus in Chlamydomonas reinhardtii result in a "uniflagellar" phenotype in which flagellar assembly occurs preferentially from the older basal body and ultrastructural defects reside in the transition zones. The UNI2 gene encodes a protein of 134 kDa that shares 20.5% homology with a human protein. Immunofluorescence microscopy localized the protein on both basal bodies and probasal bodies. The protein is present as at least two molecular-weight variants that can be converted to a single form with phosphatase treatment. Synthesis of Uni2 protein is induced during cell division cycles; accumulation of the phosphorylated form coincides with assembly of transition zones and flagella at the end of the division cycle. Using the Uni2 protein as a cell cycle marker of basal bodies, we observed migration of basal bodies before flagellar resorption in some cells, indicating that flagellar resorption is not required for mitotic progression. We observed the sequential assembly of new probasal bodies beginning at prophase. The uni2 mutants may be defective in the pathways leading to flagellar assembly and to basal body maturation.     

Reconstructing Indian-Australian phylogenetic link

Background  

An early dispersal of biologically and behaviorally modern humans from their African origins to Australia, by at least 45 thousand years via southern Asia has been suggested by studies based on morphology, archaeology and genetics. However, mtDNA lineages sampled so far from south Asia, eastern Asia and Australasia show non-overlapping distributions of haplogroups within pan Eurasian M and N macrohaplogroups. Likewise, support from the archaeology is still ambiguous.     

Amphiphilic amine-N-oxides with aliphatic alkyl chain act as efficient superoxide dismutase mimics, antioxidants and lipid peroxidation blockers in yeast

Amphiphilic 3-(alkanoylamino)propyldimethylamine-N-oxides with different length of the alkyl chain, i.e. different hydrophilic-lipophilic balance, act in micromolar concentrations as SOD mimics by lifting the inhibition of aerobic growth caused by SOD deletions in Saccharomyces cerevisiae. They also enhance the survival of sod mutants of S. cerevisiae exposed to the hydrophilic superoxide-generating prooxidant paraquat and the amphiphilic hydroperoxide-producing tert-butylhydroperoxide (TBHP), and largely prevent TBHP-induced peroxidation of isolated yeast plasma membrane lipids. Unlike the SOD-mimicking effect, the magnitude of these effects depends on the alkyl chain length of the amine-N-oxides, which incorporate into S. cerevisiae membranes, causing fluidity changes in both the hydrophilic surface part of the membrane and the membrane lipid matrix. Unlike wild-type strains, the membranes of sod mutants were found to contain polyunsaturated fatty acids; the sensitivity of the mutants to lipophilic pro-oxidants was found to increase with increasing content of these acids. sod mutants are useful in assessing pro- and antioxidant properties of different compounds.     

Fetal cardiovascular responses to asphyxia induced by decreased uterine perfusion

Cardio-respiratory responses to asphyxia produced by decreased uterine perfusion were studied in 15 sheep fetuses. In chronic (spinal-anesthetized) and acute (inhalation-anesthetized) preparations, we measured fetal PO2, PCO2, pH, heart rate, arterial and umbilical venous pressures at rest and 5 min after controlled reductions of maternal aortic blood flow. Umbilical blood flow was determined by electromagnetic flow transducer on the fetal descending aorta with the iliac arteries ligated, in conjunction with radionuclide-labelled microspheres. In contrast to previous studies in which fetal hypoxaemia was produced by decreased maternally inspired O2 concentrations, decreasing degrees of uterine perfusion were associated with increasing degrees of hypercapnea and acidemia, as well as hypoxaemia. In chronic experiments, heart rate and umbilical blood flow fell significantly in response to decreased uterine perfusion with all degrees of hypoxaemia studied. In acute experiments, during the control period, PO2 values were similar to those of chronic experiments while values for pH and umbilical blood flow were lower and those for umbilical vascular resistance were higher. In the acute experiments, hypoxic stresses identical to those in the chronic studies failed to produce significant hemodynamic changes, except for bradycardia in response to severe hypoxaemia. These differences were apparently due to the pharmacologic effects of halothane and the operative stresses.     

Research versus practice: The dilemmas of research ethics in the era of learning health‐care systems

In this article we attempt to answer the question of how the ethical and conceptual framework (ECF) for a learning health‐care system (LHS) affects some of the main controversies in research ethics by addressing five key problems of research ethics: (a) What is the difference between practice and research? (b) What is the relationship between research ethics and clinical ethics? (c) What is the ethical relevance of the principle of clinical equipoise? (d) Does participation in research require a higher standard of informed consent than the practice of medicine? and (e) What ethical principle should take precedence in medicine? These questions allow us to construct two opposite idealized positions on the distinction between research and practice: the integration model and the segregation model of research and practice. We then compare the ECF for an LHS with these two idealized positions. We argue that the ECF for a LHS does not, in fact, solve these problems, but that it is a third, separate position in the relationship between research ethics and clinical ethics. Moreover, we suggest that the ECF for a LHS raises new ethical problems that require additional ethical analysis and justification. Our article contributes to the discussion on the relationship between research ethics and clinical ethics, revealing that although a learning health‐care system may significantly change the landscape of health care, some ethical dilemmas still require resolving on both theoretical and policy‐making levels.     

Antioxidative activity of new N-oxides of tertiary amines: membrane model and chromogen studies

Potential antioxidative activities of three series of newly synthesized N-oxides were studied. Individual components in each of the series differed in the lipophilicities and number of free radical scavenging groups. Various methods were used to determine their antioxidative efficiencies: Prevention of erythrocyte membrane lipid oxidation induced by UV irradiation and chromogen experiments in which antioxidative efficiencies of compounds were compared to that of the standard antioxidant Trolox (a water-soluble vitamin E analogue). Additionally, some hemolytic (pig erythrocytes) and differential scanning calorimetry (DSC) measurements were performed to determine a mechanism of the interaction between membranes and N-oxides. It was found that N-oxides, especially those of long alkyl chains (> C12H25), readily interacted with both, erythrocyte and liposomal membranes. No marked differences were found in their protection of erythrocytes against oxidation. In most cases inhibition of oxidation changed between 15% and 25%. Still, it was far better than in chromogen experiments where suppression of free radicals reached 20% in the best case. It may be concluded that antioxidative capabilities of N-oxides are moderate. Studies on the interaction mechanism showed that incorporation of particular compounds into model membranes varied. Hemolysing activities of compounds increased with the elongation of the alkyl chain but differed for corresponding compounds of particular series indicating that lipophilicity of compounds is not the only factor determing their interaction with erythrocyte membranes. DSC experiments showed that N-oxides, upon incorporation into 1,2-dipalmitoyl-3-sn-phosphatidylcholine liposomes, shifted the subtransition (Tp) and the main transition (Tm). The shifts observed depended on the alkyl chain length. The effects differed for each series. It seems that in the case of long alkyl chain compounds the domain formation may take place. Generally, the decrease of Tm was greatest for the same compounds that exhibited the best hemolytic efficacy. The same conclusion concerns the decrease of cooperativity of the main transition and the observed changes suggest an increase in membrane fluidity. Both, erythrocyte and DSC experiments seem to indicate that compounds of particular series incorporate in a somewhat different way into membranes.