A Nuclear Marker for Mammalian Cells and Its Use with Intracerebral Transplants

The Hoechst dye staining method has been successfully applied to the central nervous system in mammals and its use has been demonstrated in intracerebral transplantation. The technique is rapid, simple and based on intrinsic nuclear properties. It was found to be permanent and valid whatever the animal strains or ages, allowing the distinction of rat cells from those of mouse, studied either separately or in a cross-transplantation model. It permitted the detection of grafted cells in the area of transplantation and the observation of early dispersion around the implantation site. Moreover, it can be combined with immunohistochemistry as demonstrated by a myelin marker in a relevant model. Immunodetection can thus help to directly observe grafted cells, at distance from the locus of transplantation, confirming their presence in the graft-type myelin patches.

Because of its rapid performance, this technique can be used systematically after transplantation to check for the presence of grafted cells in the host.     

Polymorphism and mapping of the IGF1 gene,and absence of association with stature among African Pygmies

Summary Probes detecting restriction fragment length polymorphisms (RFLPs) in the insulinlike growth factor (IGF1) gene were isolated and allele frequencies in different human populations determined. No difference was detected between the distribution of IGF1 alleles in Pygmies versus non-Pygmy black Africans, despite the proposal that a defect in the IGF1 gene might be responsible for Pygmy short stature. This was supported by the absence of a correlation of IGF1 genotype with height in the C.A.R. Pygmies. Polymerase chain reaction (PCR) and direct sequencing failed to demonstrate an alteration in the region upstream the IGF1 start site in Pygmies. Linkage analysis demonstrated that IGF1 is tightly linked to the phenylalanine hydroxylase gene on chromosome 12q22–24.1.     

The role of patient expectations in predicting outcome after total knee arthroplasty

Introduction  

Patient's expectations are variably reported to influence self-rated outcome and satisfaction after medical treatment; this prospective study examined which of the following was the most important unique determinant of global outcome/satisfaction after total knee arthroplasty (TKA): baseline expectations; fulfilment of expectations; or current symptoms and function.     

Efficient tuning of potential parameters for liquid–solid interactions

Spherical and cylindrical water droplets on silicon surface are studied to tune the silicon–oxygen interaction. We use molecular dynamics simulations to estimate the contact angle of two different shaped droplets. We found that the cylindrical droplets are independent of the line tension as their three phases curvature is equal zero. Additionally, we compare an analytical model, taking into account or not the Tolman length and we show that for spherical small size droplets, this length is important to be included, in contrast to cylindrical droplets in which the influence of the Tolman length is negligible. We demonstrate that the usual convenient way to exclude linear tension in the general case can give wrong results. Here, we consider cylindrical droplets, since their contact angle does not depend on the droplet size in the range of few to 10ths of nanometres. The droplets are stabilised due to the periodic boundary conditions. This allows us to propose a new parameterisation for nanoscale droplets, which is independent the size of the droplets or its shape, minimising at the same time the calculation procedure. With the proposed methodology, we can extract the epsilon parameter of the interaction potential between a liquid and a solid from the nanoscaled molecular simulation with only as input the macrosized experimental wetting angle for a given temperature.     

The Unique Non-Catalytic C-Terminus of P37delta-PI3K Adds Proliferative Properties In Vitro and In Vivo

The PI3K/Akt pathway is central for numerous cellular functions and is frequently deregulated in human cancers. The catalytic subunits of PI3K, p110, are thought to have a potential oncogenic function, and the regulatory subunit p85 exerts tumor suppressor properties. The fruit fly, Drosophila melanogaster, is a highly suitable system to investigate PI3K signaling, expressing one catalytic, Dp110, and one regulatory subunit, Dp60, and both show strong homology with the human PI3K proteins p110 and p85. We recently showed that p37δ, an alternatively spliced product of human PI3K p110δ, displayed strong proliferation-promoting properties despite lacking the catalytic domain completely. Here we functionally evaluate the different domains of human p37δ in Drosophila. The N-terminal region of Dp110 alone promotes cell proliferation, and we show that the unique C-terminal region of human p37δ further enhances these proliferative properties, both when expressed in Drosophila, and in human HEK-293 cells. Surprisingly, although the N-terminal region of Dp110 and the C-terminal region of p37δ both display proliferative effects, over-expression of full length Dp110 or the N-terminal part of Dp110 decreases survival in Drosophila, whereas the unique C-terminal region of p37δ prevents this effect. Furthermore, we found that the N-terminal region of the catalytic subunit of PI3K p110, including only the Dp60 (p85)-binding domain and a minor part of the Ras binding domain, rescues phenotypes with severely impaired development caused by Dp60 over-expression in Drosophila, possibly by regulating the levels of Dp60, and also by increasing the levels of phosphorylated Akt. Our results indicate a novel kinase-independent function of the PI3K catalytic subunit.     

Physiographic and climatic events in the Chihuahuan Desert lead to the speciation and distinct demographic patterns of two sister Sceloporus lizards

The biogeographic history of the Chihuahuan Desert is known to be complex, and there is evidence of the effects of physiographic and climatic events in species diversification and demographic population changes in many taxa. Here, using DNA sequence data, we studied the influence of the physiographic and climatic events that occurred in the Chihuahuan Desert during the Pliocene–Pleistocene transition on the speciation and evolutionary history of the sister lizard species Sceloporus cyanostictus and S. gadsdeni. First, based on mtDNA and nDNA sequences, we estimated the divergence times of the sister species. Then, based on mtDNA sequences, we investigated the demographic history of both species within a phylogeographic framework. The divergence time was inferred to be 1.48 Mya, date that corresponds to the existence of a large lake in the Mapimian subprovince, between the current geographic locations of S. cyanostictus and S. gadsdeni. This lake could have acted as a barrier, leading to the speciation of both species. For the demographic history of the two species, we identified two distinct patterns: the population expansion of S. gadsdeni within the Last Glacial Maximum and the potential population decline of S. cyanostictus. Our results can be used as a guide for the study of other aspects that could be critical to developing conservation actions that ensure the survival of not only S. gadsdeni and S. cyanostictus, but also other co‐occurring lizard species.     

Hadrosauroid Dinosaurs from the Late Cretaceous of the Sultanate of Oman

Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined.