PubMed Health⌕ Search

Biomedical subjects

V B Ritov

Publications and source records attributed to V B Ritov.

68 records · Page 4Linked to original sources
PubMed1976

[Concentration of components of the adenylate system in heavy and light fractions of the sarcoplasmic reticulum of skeletal muscles and sensitivity of these fractions to the effects of imidazole-containing compounds and caffeine].

Fragments of sarcoplasmic reticulum from rabbit sceletal muscles sedimented within the range from 2000 g to 8000 g (heavy fraction) and 8000 g to 40000 g (light fraction) and washed with 0.6 M KCl, were practically free of adenylatecyclase activity. Phosphodiesterase cAMP was not found in the light fraction, while its activity in the heavy fraction was 500 pmol of cAMP/min per mg of protein. Both fractions contain bound cAMP (1-2 pmol/mg of protein) and specific sites of cAMP binding, the binding constant being approximately 10(6)M-1. The number of binding sites is 60 pmol/mg of protein for the heavy and 30 pmol/mg of protein for the light fractions. The level of phosphodiesterase activity in the heavy fraction correlates with its sensitivity to imidazole, anserine and caffeine. Imidazole and anserine increase in 1.5-1.8 times the value of Ca2+/ATP in the heavy fraction and produce no effect on Ca2+ transport by the light fraction. Caffeine decreases almost twice the Ca2+/ATP value in the heavy fraction and has practically no effect on Ca2+ absorption by enzymes of the light reticulum fraction. Imidazole and anserine activate membrane-bound phosphodiesterase, while caffeine inhibits it. It is suggested that structural rearrangements of membrane-bound phosphodiesterase under the effect of caffeine, imidazole and anserine are responsible for changes in the efficiency of Ca2+ transport by fragments of the heavy reticulum fractions.

Adenosine Triphosphatases↗
PubMedDate not supplied

Murine pulmonary Ca(2+)-transport system activated by allergic immune response retains sensitivity to oxidative stress.

Exaggerated oxygen radical production by airway cells may contribute to increased airway responsiveness and heightened smooth muscle constriction in asthmatic lungs. Smooth muscle cell contractility in the lung is regulated by Ca2+ homeostasis. The contribution of inflammatory cells to these events is unclear. A murine model of allergic pulmonary hypersensitivity was developed to study the role of Ca2+ transport in allergic pulmonary reactions. Sensitization of mice was accomplished by injection with ovalbumin (OA) (1 or 50 micrograms) or OA (1 microgram) plus Al(OH)3. Pulmonary responses were elicited by inhalation provocation challenge with OA aerosol and quantified by the extent of inflammatory cell infiltrate at 24 h. Increased Ca2+ transport was found in microsomes and homogenates of the lung after antigen challenge. Activation of Ca2+ transport was correlated with the severity of the allergic pulmonary response as evidenced from specific antibody production and inflammatory cell infiltrate. The greatest increase in Ca2+ transport was noted in microsomes from mice sensitized with OA plus adjuvant. Ca2+ transport in sensitized, but not in control mice, was responsive to oxidative stress induced by addition of phenol and hydrogen peroxide. Lung homogenates from both groups of animals responded similarly to phenoxyl radical-induced oxidative stress induced by phenol plus exogenous tyrosinase. These results are the first to indicate heightened Ca2+ transport in pulmonary microsomes following an allergic lung response and emphasize the role of aluminum hydroxide in enhancing allergic reactions in the lung. The responsiveness of the system to oxidative stress suggests that oxidative mechanisms may contribute to the physiologic and pathologic manifestations, such as airway hyperreactivity, associated with allergic pulmonary disease.

Animals↗
PubMedDate not supplied

[Interaction of spin-labeled saturated and unsaturated fatty acid derivatives with biological membrane lipid and protein components].

Interaction of saturated and unsaturated derivatives of spin-labelled fatty acids (2,2,6,6-tetramethyl-4-palmitoylpiperidil-l-oxyl (I) and synthetized by us 2,2,6,6-tetramethyl-4-oleoylpiperidil-1-oxyl (II) with sarcoplasmic reticulum membranes, retina rod outer segments and erythorocyte ghosts was studied. ESR spectra of the probe I are practically unresolved singlets, whereas ESR spectra of the probe II appear as more of less resolved triplet signals. The difference in ESR spectra of the probes I and II is the result of distribution of the probe I in pure lipid regions of membranes, the probe II being located both in lipid bilayer and hydrophobic areas of proteins.

Animals↗
PubMedDate not supplied

[The suppression of the Ca ATpase activity of rat kidney microsomes under the action of blood plasma as an index of the severity of the status of pyelonephritis patients].

Whether blood plasma from 63 pyelonephritis patients can inhibit Ca-ATPase activity when compared to known toxicity marker (middle-sized molecule number) was studied. This was done to assess diagnostic potentialities of the test based on the ability of plasma from pyelonephritis patients to inhibit the test enzymatic system, i. e. Ca-ATPase activity of the microsome fraction from renal cortex in intact rats. The inhibition of Ca-ATPase activity by the plasma is shown to correlate with inflammation activity and the patients condition. In pyodestructive acute pyelonephritis this inhibition reached 60.6 +/- 3.86%, in acute serous pyelonephritis 36.02 +/- 1.54%. It follows, that the above parameter is more informative than the number of middle-sized molecules and can be introduced as one of the criteria of the patients' condition and for choice of treatment.

Acute Disease↗