Roughness of the globular protein surface]

The area and volume of the approximating ellipsoids taken from low resolution X-ray data have been calculated for 65 globular proteins. It has been shown that the dependence of these values on the protein molecular mass (M) coincides with those for even isometric bodies. This indicates that the asymmetry of globular proteins does not grow with the increase of their sizes. At the same time the 0.73 slope of the log-log dependence of the accessible surface area (A(s)) on the protein molecular mass differing from the value of 0.67 for even isometric bodies was observed (Miller S. et al., J. Mol. Biol. 1987. V.196. P.641). This can be explained by peculiarities of the protein surface. The method of molecule shape recovery by spherical harmonics has shown that the domain organization of protein molecule cannot explain the observed difference. Therefore the more detailed analysis of protein surface structure would be necessary.     

Stepdown ofloxacin therapy in bronchopulmonary diseases

Ofloxacin was used in the treatment of 15 patients (12 with pneumonia and 3 with aggravated chronic bronchitis). The drug was administered at first intravenously in a dose of 200 mg twice a day for 3 days and then orally in the same dosage. Before the treatment Streptococcus, Pneumococcus and Klebsiella strains were isolated from the sputum specimens (12, 2 and 2 cases respectively). All the isolates except for 3 Streptococcus strains were susceptible to ofloxacin. After the treatment the recovery and improvement were stated in 14 patients. One patient with pneumonia at the background of chronic bronchitis due to resistant Streptococcus strains was excluded from the trial since the treatment with ofloxacin failed. 252 isolates from the sputum specimens of the patients with pulmonary affections were subjected to the laboratory tests and high activity of the fluoroquinolone against the gram-positive and gram-negative organisms was shown. The isolates were often resistant to tetracycline. It was concluded that the use of ofloxacin in the successive therapy of patients with pulmonary diseases was expedient.     

The effect of low ionic strength solutions on the structure and function of the nucleoli in living ESK cells

The effect of a 20% Hanks [correction of Hanx] solution on living cells of pig embryo kidney culture induces sharp changes in the structural and functional organization of nucleoli. 10-15 min after the beginning of the effect, no nucleoli are observed under the light microscope. The ultrathin sections reveal only fibrillar centers (FC) and a dense fibrillar component. Under these conditions nucleoli do not incorporate 3H-uridine. However, 30-120 min after the cells are transferred from the hypotonic to the normal isotonic medium, the nucleoli cannot be distinguished from initial ones by their form, size, location in the nucleus, ultrastructure and the 3H-uridine labelling pattern. This indicates that the effect of a 20% Hanks [correction of Hanx] solution on nucleoli of living PE cells is reversible. It has been suggested that reconstruction of nucleoli in the full culture medium may proceed at the expense of both synthesis de novo and the material of initial nucleoli.     

The effect of acute hypoxia on the dynamic formation of unfused tetanus in the rat extensor digitorum longus

The effect of acute hypoxia on a single twitch and tetanic twitch parameters, was studied. The postactivation phase was found to be independent of the oxygen delivery.     

Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata

Since EGF is known to protect and stimulate the activity of dopaminergic neurons, an autoradiographic study of [125I]EGF binding sites was performed in the striatum and pallidal complex in parkinsonian syndromes. The analysis was performed on postmortem brain tissues of three control subjects, three patients with Parkinson's disease, and three patients with progressive supranuclear palsy, another parkinsonian syndrome in which dopaminergic neurons also degenerate. Since all six patients had been treated with L-Dopa, we also analyzed the effects of this drug in an animal model of Parkinson's disease. Quantitative analysis of [125I]EGF binding was performed on the brains of three control monkeys, nine monkeys rendered parkinsonian by MPTP intoxication, three of which were treated with L-Dopa. An increased density of [125I]EGF binding was observed at anterior levels in the dorsal striatum, but not in the pallidum, of patients with Parkinson's disease and progressive supranuclear palsy. [125I]EGF binding was unchanged in parkinsonian monkeys whether or not they had been treated with L-Dopa. The data suggest an increased expression of EGFRs in the striatum in chronic parkinsonian syndromes but not in acute models of the disease.     

New Rapid HPLC Method for Separation and Determination of Benzo[A]Pyrene Hydroxyderivatives

A new rapid, one-step semi-quantitative HPLC-MS method applicable for the separation and characterization of the group of total 10 BaP hydroxyderivatives (1-hydroxy benzo[a]pyrene, 2-hydroxybenzo[a]pyrene, 3-hydroxybenzo[a]pyrene, 4-hydroxybenzo [a]pyrene, 7-hydroxybenzo[a]pyrene, 8-hydroxybenzo[a]pyrene, 9-hydroxybenzo[a]py rene, 10-hydroxybenzo[a]pyrene, 12-hydroxybenzo[a]pyrene and benzo[a]pyrene-9,10-dihydrodiol) was developed, involving electrospray ionization technique (ESI) in positive mode. Its qualitative and quantitative characteristics were selected by the analysis of the model OH-BaP mixture consisted of compounds mentioned above. The model system offered the linear response in the whole concentration range used (50–1000 ng.mL^?1) as well as the resolution sufficient for semi-quantitative purposes (R_S > 0.5). Subsequently, the suitability of the developed method was tested on BaP decomposition products to be formed during photooxidation at λ = 365 nm. These analyses confirmed the applicability of the proposed method, succeeding in the identification of 5 BaP hydroxyderivatives formed upon the BaP photooxidation experiment.     

Oxidation in liposomes from egg phosphatidylcholine loaded with L-3,4-dihydroxyphenylalanine (DOPA) and dopamine: mutual effect of components

Effectiveness of continuous positive airway pressure (CPAP) as a treatment of obstructive sleep apnea can be limited by poor compliance, but little is known about how to improve compliance. We performed a randomized, controlled clinical trial among 33 subjects of two interventions to improve compliance. One group of subjects received weekly phone calls to uncover any problems and encourage use, another received written information about sleep apnea and the importance of regular CPAP use, and a third served as control subjects. We found that intervention improved CPAP compliance (p = 0.059) and that the effect was particularly strong when intervention occurred during the first month of CPAP treatment (p = 0.004). Although the sample size did not allow definitive investigation of other explanatory variables, subjects with lower levels of education or those with relatives who used CPAP may have benefited from intervention more than other subjects. We conclude that simple, inexpensive efforts to improve compliance with CPAP can be effective, especially when applied at the start of CPAP treatment, but optimal intervention may vary with certain patient characteristics.