Polyribosome formation from haemoglobin ribonucleoprotein in vitro

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evaluation of a high-resolution regional climate simulation over Greenland

A simulation of the 1991 summer has been performed over south Greenland with a coupled atmosphere–snow regional climate model (RCM) forced by the ECMWF re-analysis. The simulation is evaluated with in-situ coastal and ice-sheet atmospheric and glaciological observations. Modelled air temperature, specific humidity, wind speed and radiative fluxes are in good agreement with the available observations, although uncertainties in the radiative transfer scheme need further investigation to improve the model’s performance. In the sub-surface snow-ice model, surface albedo is calculated from the simulated snow grain shape and size, snow depth, meltwater accumulation, cloudiness and ice albedo. The use of snow metamorphism processes allows a realistic modelling of the temporal variations in the surface albedo during both melting periods and accumulation events. Concerning the surface albedo, the main finding is that an accurate albedo simulation during the melting season strongly depends on a proper initialization of the surface conditions which mainly result from winter accumulation processes. Furthermore, in a sensitivity experiment with a constant 0.8 albedo over the whole ice sheet, the average amount of melt decreased by more than 60%, which highlights the importance of a correctly simulated surface albedo. The use of this coupled atmosphere–snow RCM offers new perspectives in the study of the Greenland surface mass balance due to the represented feedback between the surface climate and the surface albedo, which is the most sensitive parameter in energy-balance-based ablation calculations.Peer reviewe

Bovine leukaemia virus and enzootic bovine leukosis

Infection of bovines with bovine leukaemia virus (BLV) manifests itself in either of two ways: 30-70% of carriers develop persistent lymphocytosis (PL), with the viral genome integrated at a large number of different sites in the DNA of the affected B-lymphocytes, without causing any chromosomal abnormalities. Only 0,1-10 % of carriers develop lymphoid tumours, which also consist of B-lymphocytes. In contrast to PL, however, they are of mono- or oligoclonal origin in terms of the integration site, which is characteristic for each tumour. All cells contain one or more copies of the viral genome, chromosomal aberrations are common and if deletions are present they are invariably found in the 5' -half of the virus DNA sequence. In both types of affected cells transcription is repressed in vivo, but transient virus production can be induced in vitro and detected by means of syncytia induction or haemagglutination. In vivo production of virus in some unknown cell is suggested by the presence of high antibody titres in infected animals, especially against the envelope glycoprotein gp51 . This can be detected by various techniques such as immunodiffusion, radioimmune assay or ELISA. Monoclonal antibodies against gp51 have revealed 8 epitopes, 3 of which are recognized by neutralizing antibodies and one by a cytolytic antibody. The BLV genome, about 9 kb in size, have been cloned, and some of the information obtained on its molecular structure and function is discussed. It codes for at least 4 non-glycosylated and 2 glycoproteins. Of special interest is the recently discovered serological relationship between some of the non-glycosylated proteins and those of the human T-cell leukaemia virus. The functional role of BLV in leukaemogenesis is largely unknown. The presence of the viral genome seems to be necessary for the maintenance of the transformed state, but not its continuous expression nor an LTR- mediated promotion of transcription of cellular genes. No oncogene is carried by the virus. Although bovine leukosis is not of major economic importance, its eradication is desirable and feasible in countries with a relatively low incidence, by means of testing and elimination. For endemic situations vaccination would be preferable, and distinct possibilities exist for the development of gp51 based vaccinesThe articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Comprehensive Analysis of Leukocytes, Vascularization and Matrix Metalloproteinases in Human Menstrual Xenograft Model

In our previous study, menstrual-like changes in mouse were provoked through the pharmacologic withdrawal of progesterone with mifepristone following induction of decidualization. However, mouse is not a natural menstruation animal, and the menstruation model using external stimuli may not truly reflect the occurrence and development of the human menstrual process. Therefore, we established a model of menstruation based on human endometrial xenotransplantation. In this model, human endometrial tissues were transplanted subcutaneously into SCID mice that were ovarectomized and supplemented with estrogen and progestogen by silastic implants with a scheme imitating the endocrinological milieu of human menstrual cycle. Morphology, hormone levels, and expression of vimentin and cytokeratin markers were evaluated to confirm the menstrual-like changes in this model. With 28 days of hormone treatment, transplanted human endometrium survived and underwent proliferation, differentiation and disintegration, similar to human endometrium in vivo. Human CD45+ cells showed a peak of increase 28 days post-transplantation. Three days after progesterone withdrawal, mouse CD45+ cells increased rapidly in number and were significantly greater than human CD45+ cell counts. Mouse CD31+ blood vascular-like structures were detected in both transplanted and host tissues. After progesterone withdrawal, the expression levels of matrix metalloproteinases (MMP) 1, 2, and 9 were increased. In summary, we successfully established a human endometrial xenotransplantation model in SCID mice, based on the results of menstrual-like changes in which MMP-1, 2 and 9 are involved. We showed that leukocytes are originated from in situ proliferation in human xenografts and involved in the occurrence of menstruation. This model will help to further understand the occurrence, growth, and differentiation of the endometrium and the underlying mechanisms of menstruation

Progesterone regulation of implantation-related genes: new insights into the role of oestrogen

Genomic profiling was performed on explants of late proliferative phase human endometrium after 24-h treatment with progesterone (P) or oestradiol and progesterone (17β-E2+P) and on explants of menstrual phase endometrium treated with 17β-E2+P. Gene expression was validated with real-time PCR in the samples used for the arrays, in endometrium collected from early and mid-secretory phase endometrium, and in additional experiments performed on new samples collected in the menstrual and late proliferative phase. The results show that late proliferative phase human endometrium is more responsive to progestins than menstrual phase endometrium, that the expression of several genes associated with embryo implantation (i.e. thrombomodulin, monoamine oxidase A, SPARC-like 1) can be induced by P in vitro, and that genes that are fully dependent on the continuous presence of 17β-E2 during P exposure can be distinguished from those that are P-dependent to a lesser extent. Therefore, 17β-E2 selectively primes implantation-related genes for the effects of P

Regional climate modeling for Asia

The regional climate model (RCM) with higher resolution and sophisticated physical processes can reproduce and project fine-scale climate information, which cannot be captured by the global climate model (GCM). Therefore, we developed the Seoul National University Regional Climate Model (SNURCM) in the 1990s to simulate the intrinsic and detailed climate prevailing in Asia. In this study, we reviewed the developmental processes of the SNURCM and its application researches. In the simulation of regional climate over Asia, systematic errors can be generated because of natural characteristics such as complex land-surface conditions and topography, warm ocean conditions, and strong seasonal monsoon circulation and convection. Numerous methods and techniques have been applied to reduce these errors and improve the SNURCM. For long-term simulations without climate drift, the spectral nudging technique as well as the traditional relaxation method was employed for the boundary conditions. To represent reasonable interactions between earth systems, a simple ocean model and an advanced land-surface model were implemented into the SNURCM. Physical schemes for precipitation and vertical diffusion developed for short-term numerical weather prediction models were optimized or improved for long-term simulation. The SNURCM has been applied to future climate projection, reproduction of extreme climate, and seasonal forecasting. Furthermore, the model has served as a part of the multi-model comparison program and an ensemble of international research programs