The frequency and the distribution of HLA-B27 subtypes in spondylarthropathy (SpA) patients and controls were investigated in a sample Turkish population. B27 subtyping was performed by PCR-SSP ...method in two groups: 49 unrelated HLA-B27 positive Turkish patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group Criteria, and 55 HLA-B27 positive healthy controls. The frequency of HLA-B*27 was 2.6% in the Turkish population, and B*2705 was the predominant allele among patients with SpA. The difference was mainly between male patients and male controls The proportion of B*2705 among B27-positive patients and controls was significantly different (P=0.02). Our study supports other reports from different populations which showed that B*2705 and B*2702 were more frequent in Caucasian patients with SpA.
Telomeric sequences, located at the very end of the chromosomes, compensate for the chromosomal shortening as it happens after each round of cell division. Telomeric sequences influence the progress ...of cellular senescence and cancer progression. It has been reported that telomeres are shortened in acute leukemias where the cell turnover is high. B-cell chronic lymphocytic leukemia (CLL) is a particularly interesting haematological malignancy in regard to telomere dynamics because most of the malignant cells in CLL are mitotically inactive. In this study, we analysed the telomere length in patients with B-cell CLL in a comparison with the control group by using ddPRINS technique. Twenty patients with CLL and four healthy donors as a control group were included. We found short telomeres and no detectable telomeric repeats at the sites of chromosome fusion. We hypothesise that the telomeric erosion in CLL may reflect the dominance of malignant cells with an abnormally long life span. These cells may have encountered many antigenic stimulants in the past and hence underwent multiple clonal expansions. Our findings imply that shortened telomeres in CLL may be reflecting the “history” of the disease and serve as an independent prognostic factor.
A multi-disciplinary reservoir characterization project was undertaken in the Glenn Pool Field, Oklahoma. The geophysical objective was to aid in reservoir description by providing subsurface images ...using crosswell seismic tomography. Tomography is a method of estimating the subsurface velocity distribution based on observed and modeled traveltime differences. It requires accurate ray path and traveltime calculations. Seismic anisotropy is the angular variation of velocity with propagation angle, at one particular point. Conventional geophysical forward and inverse methods often assume isotropic subsurface conditions, ignoring anisotropy. Due to its severity, in the Glenn Pool Field the effects of seismic anisotropy on traveltime calculations and tomography cannot be ignored. Isotropic tomography fails to yield a reasonable subsurface image. This research follows a five-step approach to address the anisotropy problem: (1) Show the evidence of anisotropy, (2) Characterize anisotropy, (3) Develop an anisotropic ray tracing code, (4) Develop a velocity updating scheme for anisotropic tomography, and (5) Demonstrate the theoretical developments on synthetic and field data. This methodology was successfully applied to the Glenn Pool data. The tomographic result is an acceptable solution which yields modeled traveltimes consistent with the observed traveltime data. The velocities obtained from tomography are in good agreement with sonic derived velocities. Nevertheless, crosswell seismic imaging bears the uncertainties and variability common to all inverse problems. The results vary, depending on how the processing constraints are imposed or how well the physics of energy propagation is characterized. A variety of processing algorithms applied to the same input data resulted in significantly different tomograms, demonstrating non-uniqueness of the problem. The result is in good agreement with the geological work carried out independently from tomography. The effects of anisotropy, if not taken into account properly, will be detrimental to image quality. The methods introduced in this dissertation are useful in dealing with anisotropy, without resorting to weak anisotropy assumptions.
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