Helix-coil transitions in nucleoprotein: Computer-generated curves for independent melting of double-stranded regions with fixed ends

Helix-coil transitions in nucleoprotein at low salt concentrations are known to be characterized by two phases of the process: independent melting of uncomplexed “naked” regions without rearrangement of proteins, followed, at higher temperatures, by melting of complexed DNA. Blocking at the ends of these regions increases their thermal stability and three is a shift of 10–20°C in t_m of the melting profiles. In this study the basic assumption is that the loop entropy effect is mainly responsible for such stabilization. Calculations are made using conventional h-c transition theory for a system of independently melted segments with fixed ends. Segments are either homosize or have randomly distributed lengths. Calculated melting curves are used to obtain t_m, and transition width-dependence on segment length (or average length when randomly distributed) and on the nucleation parameter σ. Base-pair heterogeneity is taken into account by averaging over different base-pair distributions in the individual segments, using Gaussian distribution around the overall (G+C)-content. It is shown that this causes only an additional widening of the transition but no additional t_m shift. Comparison is made with similar systems in the literature. The main conclusion drawn is that the treatment proposed may be useful for analysis of the lower temperature melting phase in nucleoprotein at low counterion concentrations. It may be used as an independent method to reveal the features of nucleoprotein structure.     

Why are diabetic patients treated at rheumatological hospitals?]

Retrospective analysis included 316 case histories of diabetic patients treated at the Silesian Rheumatology Hospital in 1987-1988. An analysis included causes of disorders, calcium-phosphorus metabolism disturbances, lipid and purine disorders. Statistical parameters were compared with the type of diabetes mellitus, duration of the disease, sex, age and obesity. There were 10% of inflammatory rheumatic disorders (6.4% rheumatic arthritis, 1.7% of rheumatoid spondylosis and 2% of other disorders) in the analysed case histories, and 32% of degenerative disorders (19% of vertebral column joints and 12.7% of other joints). Degenerative disorders were noted more frequently in patients with diabetes mellitus type 2, treated with insulin, while spondylopathies were particularly frequent in female patients of this group. Biochemical disorders in the form of hypocalcemia and hypophosphatemia, hypertriglyceridemia, hyperuricemia, signs of lesions to the liver and kidneys were more increasing with the duration of the disease and the degree of insulin-dependence. Locomotive system disorders are not related only to primary articular lesions. They depend also on diabetic neuro-vascular complications and osteopenia.