Spin label and microcalorimetric studies of the interaction of DNA with unilamellar phosphatidylcholine liposomes

High-molecular DNA from chicken erythrocytes interacts with 1,2-dipalmitoylphosphatidylcholine in unilamellar liposomes, both in the presence and absence of Mg2+ ions. This interaction results in a phase separation in liposome membranes. The new phase induced by DNA and Mg2+ has a higher gel-liquid crystal phase transition temperature as measured by microcalorimetry. In the liquid crystalline state, the 16- and 5-doxyl stearic acid spin labels indicate changed local bilayer properties at the label position in the new phase.     

Effect of ionic milieu to the free radicals generated by phenizine methosulphate (PMS)

The effect of free radicals generated by PMS was studied for membrane damage in the presence of different ions in the erythrocyte model. The degree of membrane damage depended on the quality of ionic composition in the incubation medium. We supposed that the degree of membrane damage depends on the average life and concentration and/or reactivity of the free radicals generated. For control of this supposition free radicals were generated by PMS in the presence of Sodium-di-thionite in isosmotic, waterly systems with different ionic composition. At different time intervals the concentration of free radicals was measured by the ESR method. It seams that concentration of radicals depends on the qualitative composition of ionic milieu. The increase of the average life of free radicals generated by PMS is accompanied by decrease in their reactivity. This is reflected by a moderate membrane damage.     

Expert systems in medicine

The emergence of the artificial intelligence (AI) in computer technology and its application in the medical field enables the researchers to carry out such intelligent activities like image processing, medical reasoning systems, clinical decision supporting and natural language understanding, etc. A gastroenterological expert system application is briefly demonstrated in this paper. Similar expert systems can be seen to be useful in the research of gastrointestinal cytoprotection, including the plan of different compounds with cytoprotective effect, experimental and clinical medical research.     

Treatment of duodenal ulcers by antacid (Al-Mg-hydroxy-carbonate). A controlled, randomized, prospective, multicentre clinical trial

TISACID (a new, modern Hungarian Al-containing antacid) with a high acid-neutralizing capacity (greater than 26.8 mmol/g) also enhances gastric mucosal defense mechanisms (prostaglandin-dependent gastroprotection). A simple-blind, prospective, randomized, parallel multicentre clinical trial has been performed on both the clinical efficacy and possible side effects of TISACID monotherapy (Al-Mg-hydroxy-carbonate) on informed patients suffering from active duodenal ulcers. The study groups were as follows: Group "A": 3 g/day of TISACID (acid-neutralizing capacity = 78 mmol, n = 85), Group "B": 6 g/day of TISACID (acid-neutralizing capacity = 156 mmol, n = 88), Group "C": 12 g/day of TISACID (acid-neutralizing capacity = 312 mmol, n = 68), Group "D": (as control): (1.0 g/day cimetidine (HISTODIL, RGH, Budapest, n = 91). The total number of patients: 332. It was found that: 1. The new Hungarian antacid compound (both tablet and suspension) can essentially accelerate the healing rate of duodenal ulcers. 2. The cumulative healing rate of ulcers and the decrease of complaints can be achieved equally by relatively low doses of TISACID monotherapy and cimetidine alone. 3. There were no differences between the clinical potency and side-effects of TISACID tablet and suspension.     

In vitro method for measurement of free radical effects: effect of PMS (phenazine methosulphate) on red blood cell membrane

The aim of this study was to elaborate a simple in vitro model for rapid and quantitative measurement of free radical effects. Free radical generating characteristics of PMS were measured in the case of red blood cell (RBC) membrane. The mechanism of free radical action was investigated in MgCl2, CaCl2, BaCl2 and in Verapamil HCl medium. The most important result of the investigations is as follows: Membrane damage of RBC provoked by the mechanism of free radical generation of PMS is proportional to the intracellular K+-efflux and to the extracellular Na+-influx. The PMS dependent K+-efflux in a NaCl containing medium in the presence of CaCl2 increases significantly, while it remains unchanged in MgCl2 medium. The PMS dependent K+-efflux and Na+-influx were considerably decreased by Verapamil HCl in NaCl containing solution. We have come to the conclusion that new, non-selective pores are formed in the membrane. The measure of the damage increases in the presence of Ca2+ions and decreases in the medium containing Verapamil HCl.     

The effect of (+) cyanidanol-3 on the Na+-K+-ATP-ase and Mg++-ATP-ase activities of the rat brain in the presence and absence of ascorbic acid

The authors investigated the effects of (+) cyanidanol-3-(Catergen) in vitro on the activities of rat brain plasma membrane and microsomal Na+-K+-ATP-ase and Mg++-ATP-ase, in the presence and absence of ascorbic acid. Due to lipid peroxidation induced by low concentration of ascorbid acid, activity of both ATP-ase decreased. (+) cyanidanol-3 proved to be an effective antioxidant in this system. It inhibited the decrease of ATP-ase activity which occurred as a result of lipid peroxidation promoted by ascorbic acid.     

Purine metabolizing enzyme activities in radiosensitive tissues of mice after sublethal whole-body irradiation

The activities of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) were determined between days 1-14 in the spleen, thymus and femoral bone marrow of mice subjected to whole-body gama irradiation with a dose of 5.5 Gy. In control animals, the highest activity of ADA (as related to 10(6) cells) was recorded in the thymus (58.9 pmol.s-1), the lowest one in the femur (34.8 pmol.s-1), the PNP activity was the lowest in the thymus (14.5 pmol.s-1) and the highest in the femur (96.0 pmol.s-1). In the spleen, an elevation of ADA activity (up to 379%) was observed during the first postirradiation days; PNP activity was reduced (to 58%) on postirradiation day 3, followed by the return and even elevation on day 14 (265%). In the thymus, a parallel reduction of the activities of both enzymes appeared during the first postirradiation days, with a subsequent increase during the regeneration phase. In the femoral bone marrow, ADA and PNP activities were increased on postirradiation day 1 (275% and 201%, respectively). Reference is made to the possible relationship between the observed characteristic changes in activities and the degree of damage and/or renewal of cell population in the hemopoietic tissues after irradiation.     

Activity of "nonspecific pancreatic carboxylesterase" in rat serum in experimentally induced acute pancreatitis (preliminary results)

The aim of this study was to obtain more information on the serum level of "nonspecific pancreatic carboxylesterase" (PCE) in experimentally induced acute pancreatitis in rats. The effects of caerulein stimulation, hepatic duct ligation, bile-pancreatic duct ligation or the effect of retrograde injection of saline, 5% taurocholate and sunflower oil were investigated. The activity of PCE and amylase was measured in the serum, pancreatic tissue, pancreatic juice and ascitic fluid. The changes in PCE activity were greater (both in directions to increase or decrease) than that of amylase, produced by different experimental procedures. The results confirm the thesis that the serum activity of PCE is a more sensitive diagnostic method than that of amylase to detect the inflammatory process in the pancreas or the effect of obstruction of the pancreatic duct.     

Both wound-inducible and tuber-specific expression are mediated by the promoter of a single member of the potato proteinase inhibitor II gene family

A chimeric gene consisting of 1.3 kb of the 5' regulatory region of a member of the potato proteinase inhibitor II gene family, the coding region of the bacterial β-glucuronidase (GUS) gene and 260 bp of the proteinase inhibitor II 3'-untranslated region containing the poly(A) addition site was introduced into potato and tobacco by Agrobacterium tumefaciens mediated transformation. Analysis of transgenic plants demonstrates systemic, wound-inducible expression of this gene in stem and leaves of potato and tobacco. Constitutive expression was found in stolons and tubers of non-wounded potato plants. Histochemical experiments based on the enzymatic activity of the GUS protein indicate an association of the proteinase inhibitor II promoter activity with vascular tissue in wounded as well as in systemically induced non-wounded leaves, petioles, potato stems and in developing tubers. These data prove that one single member of the proteinase inhibitor II gene family contains cis-active elements, which are able to respond to both developmental and environmental signals. Furthermore they support the hypothesis of an inducing signal (previously called proteinase inhibitor inducing factor), which is released at the wound site and subsequently transported to non-wounded parts of the plant via the vascular system from where it is released to the surrounding tissue.