Retention of human bone marrow-derived cells in murine lungs following bleomycin-induced lung injury

We studied the capacity of adult human bone marrow-derived cells (BMDC) to incorporate into distal lung of immunodeficient mice following lung injury. Immunodeficient NOD/SCID and NOD/SCID/beta(2) microglobulin (beta(2)M)(null) mice were administered bleomycin (bleo) or saline intranasally. One, 2, 3 and 4 days after bleo or saline, human BMDC labeled with CellTracker Green CMFDA (5-chloromethylfluorescein diacetate) were infused intravenously. Retention of CMFDA(+) cells was maximal when delivered 4 days after bleo treatment. Seven days after bleo, <0.005% of enzymatically dispersed lung cells from NOD/SCID mice were CMFDA(+), which increased 10- to 100-fold in NOD/SCID/beta(2)M(null) mice. Preincubation of BMDC with Diprotin A, a reversible inhibitor of CD26 peptidase activity that enhances the stromal-derived factor-1 (SDF-1/CXCL12)/CXCR4 axis, resulted in a 30% increase in the percentage of CMFDA(+) cells retained in the lung. These data indicate that human BMDC can be identified in lungs of mice following injury, albeit at low levels, and this may be modestly enhanced by manipulation of the SDF-1/CXCR4 axis. Given the overall low number of human cells detected, methods to increase homing and retention of adult BMDC, and consideration of other stem cell populations, will likely be required to facilitate engraftment in the treatment of lung injury.     

Anti-Plasmodium activity of tetrazolium salts

We have previously reported that sulfated cyclodextrins inhibit the invasion of Plasmodium merozoites by interacting with receptors present on the surface of erythrocytes. The observation that tetrazolium salts formed stable complexes with the inhibitory sulfated cyclodextrins suggested that tetrazolium salts might have anti-Plasmodium activity as well. Evaluation of commercially available tetrazolium salts indicated that some were active in the low nanomolar range and showed specificity in their inhibition of Plasmodium. Synthesis of a further 54 structures allowed us to determine that activity results from an aromatic component attached to the tetrazolium carbon atom (R1) and its size is not critical to the activity of the compound. Nitro modifications of active compounds are poorly tolerated, however, the presence of halogen atoms on aromatic groups attached to the nitrogen atoms of the tetrazolium ring (R2 and R3) has little effect on activity. Methoxy groups are tolerated on R2 and R3 components; however, they are disruptive on the R1 component. The overall results suggest that the R1 component is interacting with a specific hydrophobic environment and the R2 and R3 components are less constrained. The activity of these compounds in several human and mouse Plasmodium cultures suggests that the compounds interact with a component of the parasite that is both essential and conserved.     

A NEW METHOD FOR THE EXTRACTION OF MACROFOSSILS FROM CALCAREOUS ROCKS USING SULPHURIC ACID

Abstract:  A new method for the extraction of calcified and/or partly pyritized macrofossils has been developed. This method is based upon the differential speeds for the dissolving of microcrystalline and macrocrystalline calcite in 38% sulphuric acid. The effectiveness of the sulphuric acid treatment is also influenced by the volume of clay minerals in the host rock. Therefore, this method is highly applicable for the extraction of macrofossils from marlstones, marly limestones, and other lithified calcareous sediments. The main advantages of this method, when compared with other chemical methods, are (1) the short treatment time, (2) the capability of dissolving the sediment on the fossil's surface, and (3) its efficiency in dissolving calcareous rocks with low porosity. This method has been successfully applied to Upper Cretaceous macrofossils from the Bohemian Cretaceous Basin. The surface of extracted macrofossils remained undamaged, exhibiting minute skeletal details; perhaps even encrusters and bioerosions.     

Polarity of alveolar epithelial cell acid-base permeability

We investigated acid-base permeability properties of electrically resistive monolayers of alveolar epithelial cells (AEC) grown in primary culture. AEC monolayers were grown on tissue culture-treated polycarbonate filters. Filters were mounted in a partitioned cuvette containing two fluid compartments (apical and basolateral) separated by the adherent monolayer, cells were loaded with the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and intracellular pH was determined. Monolayers in HCO-free Na(+) buffer (140 mM Na(+), 6 mM HEPES, pH 7.4) maintained a transepithelial pH gradient between the two fluid compartments over 30 min. Replacement of apical fluid by acidic (6.4) or basic (8.0) buffer resulted in minimal changes in intracellular pH. Replacement of basolateral fluid by acidic or basic buffer resulted in transmembrane proton fluxes and intracellular acidification or alkalinization. Intracellular alkalinization was blocked > or =80% by 100 microM dimethylamiloride, an inhibitor of Na(+)/H(+) exchange, whereas acidification was not affected by a series of acid/base transport inhibitors. Additional experiments in which AEC monolayers were grown in the presence of acidic (6.4) or basic (8.0) medium revealed differential effects on bioelectric properties depending on whether extracellular pH was altered in apical or basolateral fluid compartments bathing the cells. Acid exposure reduced (and base exposure increased) short-circuit current from the basolateral side; apical exposure did not affect short-circuit current in either case. We conclude that AEC monolayers are relatively impermeable to transepithelial acid/base fluxes, primarily because of impermeability of intercellular junctions and of the apical, rather than basolateral, cell membrane. The principal basolateral acid exit pathway observed under these experimental conditions is Na(+)/H(+) exchange, whereas proton uptake into cells occurs across the basolateral cell membrane by a different, undetermined mechanism. These results are consistent with the ability of the alveolar epithelium to maintain an apical-to-basolateral (air space-to-blood) pH gradient in situ.     

小鼠网织红细胞微观流变学特性的研究

按Bishop方法,在小鼠血液里诱导生成大量网织红细胞,然后提取网织红细胞,对其电泳率、渗透脆性、膜的流动性、细胞的变形能力和取向性进行了系统研究。研究结果表明网织红细胞在转变为成熟红细胞的短短时间内,其微观流变学特性发生了明显的变化：电泳率变小、渗透脆性变好、膜的流动性变大、细胞的变形能力变强、取向性变好,最终发育成具有全面功能的成熟红细胞。     

Effects of Nigella sativa on apoptosis and GABAA receptor density in cerebral cortical and hippocampal neurons in pentylenetetrazol induced kindling in rats

We investigated the effects of Nigella sativa on apoptosis and gamma-aminobutyric acid (GABA_A) receptor density in cerebral cortical and hippocampal neurons in a pentylenetetrazol (PTZ)-induced kindling model in rats. The PTZ kindling model was produced by injecting PTZ in subconvulsive doses to rats on days 1, 3, 5, 8, 10, 12, 15, 17, 19, 22 and 24 of the study into animals of PTZ treated (PTZ) and PTZ + N. sativa treated (PTZ + NS) groups. Clonic and tonic seizures were induced by injecting a convulsive dose of PTZ on day 26 of the study. Rats in the PTZ + NS group were treated also with a 10 mg/kg methanolic extract of N. sativa 2 h before each PTZ injection. Rats in the control group were treated with 4 ml/kg saline. The number of neurons that expressed GABA_A receptors in the hippocampus and cerebral cortex of rats in the PTZ and PTZ + NS groups increased significantly. There was no significant difference in the number of GABA_A receptors between the PTZ and PTZ + NS groups. GABA_A receptor density of the neurons in the cerebral cortex, but not hippocampus, was increased in PTZ group compared to controls. We observed a significant increase in the number of apoptotic neurons in the cerebral cortex of rats of both the PTZ and PTZ + NS groups compared to controls. We observed a significant decrease in the number of the apoptotic neurons in the cerebral cortex of rats in the PTZ + NS group compared to the PTZ group. N. sativa treatment ameliorated the PTZ induced neurodegeneration in the cerebral cortex as reflected by neuronal apoptosis and neuronal GABA_A receptor frequency.     

Low population genetic structuring of two cryptic bat species suggests their migratory behaviour in continental Europe

Although two cryptic pipistrelle bat species, Pipistrellus pipistrellus and Pipistrellus pygmaeus , belong among the most common bat species in Europe, it is still unclear whether they can migrate over long distances between summer and winter roosts. Long-distance migratory species may be expected to show low levels of genetic structuring in large areas due to regular mixing of the gene pool by mating that occurs during migration and/or hibernation. Conversely, the dispersal of gametes in sedentary species is spatially restricted, populations are more genetically structured, and isolation by relatively short distance is visible. By analysing diversity of highly variable microsatellites within and among summer colonies of both studied species in central Europe, we found that differentiation between populations is very weak. Both classical F _ST and Bayesian clustering approach failed to detect genetic structure among colonies and there was no significant isolation-by-distance pattern. The analyses of relatedness, however, revealed that individuals within colonies are more related than random suggesting philopatry of at least one sex. The results were very similar for the two species. The high level of gene flow among central European populations, even on large geographic distances, is discussed in relation with migrations, dispersal, and mating behaviour.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 103–114.