Effectiveness of combined use of verapamil and adenosine triphosphate in experimental animals

A wide application of ATP to abolish reciprocal paroxysmal tachycardia is limited by frequent and adverse effects of the drug. Experiments on 49 rats have revealed that successive intravenous injections of verapamil and ATP have a more pronounced and prolonged action than the drugs alone. It is assumed that decreased pacemaker activity of sinus nodal cells and reduced atrioventricular conduction ("binodal dysfunction") are as a result of drug calcium channel block in the cellular membranes of myocytes. Potentiation of the pharmacological action of the drugs in question may be used in the clinical setting to lower an ATP dose and to reduce the incidence of adverse effects.     

Structure of 5S rRNA within the Escherichia coli ribosome: iodine-induced cleavage patterns of phosphorothioate derivatives

The protection patterns of 5S rRNA in solution, within the ribosomal 50S subunit, 70S ribosomes, and functional complexes, were assessed with the phosphorothioate method. About 20% of the analyzed positions (G9-G107) showed strong assembly defects: A phosphorothioate at one of these positions significantly impaired the incorporation of 5S rRNA into 50S particles. The reverse has also been observed: A phosphorothioate is preferred over a phosphate residue in the assembly process at a few positions. The results further demonstrate that 5S rRNA undergoes conformational changes during the assembly in the central protuberance of the 50S subunit and upon association with the small ribosomal subunit forming a 70S ribosome. In striking contrast, when the 70S ribosomes are once formed, the contact pattern of the 5S rRNA is the same in various functional states such as initiation-like complexes and pre- and posttranslocational states.     

Fatty acids as natural uncouplers preventing generation of O2.- and H2O2 by mitochondria in the resting state

Both natural (laurate) and artificial (m-chlorocarbonylcyanide phenylhydrazone; CCCP) uncouplers strongly inhibit O2.- and H2O2 formation by rat heart mitochondria oxidizing succinate. Carboxyatractylate, an ATP/ADP antiporter inhibitor, abolishes the laurate inhibition, the CCCP inhibition being unaffected. Atractylate partially releases the inhibition by laurate and decelerates the releasing effect of carboxyatractylate. GDP is much less effective than carboxyatractylate in releasing the laurate inhibition of reactive oxygen species (ROS) formation. Micromolar laurate concentrations arresting the ROS formation cause strong inhibition of reverse electron transfer from succinate to NAD+, whereas State 4 respiration and the transmembrane electric potential difference (delta psi) level are affected only slightly. It is suggested that (i) free fatty acids operate as natural 'mild uncouplers' preventing the transmembrane electrochemical H+ potential difference (delta muH+) from being above a threshold critical for ROS formation by complex I and, to a lesser degree, by complex III of the respiratory chain, and (ii) it is the ATP/ADP-antiporter, rather than uncoupling protein 2, that is mainly involved in this antioxidant mechanism of heart muscle mitochondria.     

Purification and characterization of P33 protein of Candida utilis homologous to bgl2p of Saccharomyces cerevisiae; comparative analysis of the role of these proteins in molecular organization of the yeast cell walls

P33 protein was isolated from the cell walls of Candida utilis. Homology between P33 and Bgl2p proteins from the cell walls of Saccharomyces cerevisiae was shown. The important role of these proteins in molecular organization of yeast cell walls was demonstrated using trypsin proteolysis and the "gene disruption" method.     

Single irradiation of the pituitary with a narrow beam of protons having 200 MeV of energy in generalized breast cancer

Eighteen patients with congestive cardiomyopathy were studied by echocardiography and cardiac catheterization. Patients with coronary disease on angiography or primary valvular disease were excluded. Six patients showed mild or no mitral regurgitation; in 12 others the degree of mitral regurgitation was moderate or severe. The echocardiographic features in these patients were: (1) a dilated left ventricle (LV), (2) normal LV wall thickness, (3) reduced LV posterior wall motion, and (4) reduced or absent systolic thickening of the interventricular septum (IVS). IVS motion was reduced in 10 patients, and appeared "normal" or increased in another eight, all of whom showed moderate or severe mitral regurgitation on angiography. It is concluded that an apparent normal or increased motion of the IVS with reduced or absent systolic thickening in congestive cardiomyopathy is evidence for coexistence of significant mitral regurgitation. Reduced or absent systolic thickening can distinguish these patients from those with segmental myocardial disease and normal septa or dilated LV's due to volume overload.     

A new member of the MER2 repeat family is detected in the promoter region of the human X11 gene

AIMS: To evaluate the clinical utility of two new tests for serum trypsinogen 2 and trypsin 2-alpha 1 antitrypsin complex (trypsin 2-AAT) in diagnosing and assessing the severity of acute pancreatitis (AP) induced by endoscopic retrograde cholangiopancreatography (ERCP). PATIENTS: Three hundred and eight consecutive patients undergoing ERCP at Helsinki University Central Hospital in 1994 and 1995. METHODS: Patients were followed prospectively for pancreatitis and clinical outcome. They were tested for serum trypsinogen 2, trypsin 2-AAT, and amylase in samples obtained before and one, six, and 24 hours after ERCP. RESULTS: Pancreatitis developed in 31 patients (10%). Their median serum trypsinogen 2 increased 26-fold to 1401 micrograms/l at six hours after the procedure and trypsin 2-AAT showed an 11-fold increase to 88 micrograms/l at 24 hours. The increase in both markers was stronger in severe than in mild pancreatitis, and in patients without pancreatitis there was no significant increase. Baseline trypsinogen 2 and trypsin 2-AAT concentrations were elevated in 29% and 32% of patients, respectively. The diagnostic accuracy of a threefold elevation over the baseline value was therefore analysed. The sensitivity and specificity of these parameters in the diagnosis of post-ERCP pancreatitis was 93% and 91%, respectively, for serum trypsinogen 2 at six hours after the examination, and 93% and 90%, for trypsin 2-AAT at 24 hours. CONCLUSIONS: Serum trypsinogen 2 and trypsin 2-AAT reflect pancreatic injury after ERCP. High concentrations are associated with severe pancreatic damage. The delayed increase in trypsin 2-AAT compared with trypsinogen 2 appears to reflect the pathophysiology of AP. A greater than threefold increase in trypsinogen 2 six hours after ERCP is an accurate indicator of pancreatitis.     

The contamination of birds with organic pollutants in the Lake Baikal region

Lake Baikal is considered to be the largest reservoir of fresh natural water in the world. Nevertheless industrial enterprises on its banks as well as river effluents contaminate this unique basin. In the present study birds' eggs (15 species) collected in the Baikal region (Selenga river estuary) have been analysed. Quantitative determination of more than 40 individual organic pollutants (polycyclic aromatic hydrocarbons, phenols, organochlorine compounds) has been carried out using GC-MS as an analytical tool. The results obtained demonstrated a wide range of toxicant concentrations (2-3 orders of magnitude) for various species. Very high levels of polycyclic aromatic hydrocarbons have been detected in the eggs of Anas platyrynchos (mallard), Tringa stagnatilis (marsh sandpiper) and Podiceps auritus (slavonian grebe). These particular species also have the highest levels of other toxicants. Taking into account high rate of metabolism of certain of these compounds in birds, it has been proposed that the major route of transfer into higher trophic levels is via water and aquatic invertebrates.     

Increasing threshold of the epileptiform activity in the CA1 field of hippocampal slices of Krushinski?-Molodkina rats as protective adaptation mechanism

The Krushinsky-Molodkina rat CA1 hippocampal slices revealed an increased threshold of the epileptiform activity development, a depressed signal transmission in the presynaptic glutamatergic fibres, no long-term increase in excitability of the CA1 pyramidal neurons characteristic of Wistar rats following Mg2+ removal and K+ increase. These events suggest a protective adaptive mechanism preventing propagation of seizure activity into limbic structures of the rats.