Biomedical subjects

A Szutowicz

Publications and source records attributed to A Szutowicz.

At least 19 recordsLinked to original sources

PubMed1994

Acetylcholine synthesis in nerve terminals of diabetic rats.

Streprozotocin diabetes and extracerebral insulin affect acetyl-CoA and acetylcholine metabolism in the brain. In the present study we have shown that pyruvate utilization, acetyl-CoA content and ACh synthesis in nerve terminals from diabetic rats were 45, 30 and 50%, respectively, higher than that in healthy animals. Treatment with insulin normalized pyruvate utilization and acetylcholine synthesis but did not decrease the acetyl-CoA level. 3-Hydroxybutyrate did not affect acetyl-CoA and acetylcholine metabolism in control rats. However, in diabetic animals, 3-hydroxybutyrate significantly increased supply of acetyl-CoA for acetylcholine synthesis. These data provide evidence that increased provision of acetyl-CoA is prerequisite for activation of acetylcholine synthesis in diabetic brain.

3-Hydroxybutyric Acid↗

PubMed1994

Effect of dichloroacetate on acetyl-CoA content and acetylcholine synthesis in rat brain synaptosomes.

In potassium-depolarized synaptosomes Ca2+ inhibited oxidation of pyruvate (30%) and decreased the level of acetyl-CoA in intrasynaptosomal mitochondria (32%). On the other hand, Ca2+ facilitated provision of acetyl-CoA to synaptoplasm, since under these condition no change of synaptoplasmic acetyl-CoA and twofold stimulation of acetylcholine synthesis were found. However, in Ca(2+)-activated synaptosomes both synaptoplasmic acetyl-CoA and acetylcholine synthesis were suppressed by 1 mM (-)hydroxycitrate by 27 and 29%, respectively. It was not the case in resting synaptosomes. Dichloroacetate (0.05 mM) partially reversed the inhibitory effect of Ca2+ on pyruvate metabolism in synaptosomes and whole brain mitochondria. In Ca(2+)-stimulated synaptosomes, the dichloroacetate overcame suppressive effects of (-)hydroxycitrate on the level of synaptoplasmic acetyl-CoA and acetylcholine synthesis, but not on citrate cleavage. It is concluded that dichloroacetate may improve the metabolism of acetylcholine in activated cholinergic terminals by increasing the production of acetyl-CoA in mitochondria and increasing its provision through the mitochondrial membrane to synaptoplasm by the transport system, independent of the ATP-citrate lyase pathway.

Acetyl Coenzyme A↗

PubMed1993

Treatment of fourteen chronic active HBsAg+, HBeAg+ hepatitis patients with low dose natural human interferon alpha administered orally.

The therapy concept is based on a theory of the immunocorrective effect of orally administered natural human interferon alpha in low doses (leuHuIFN alpha (ldou)), manifolded by the logistic amplification system seated in the oral cavity. Fourteen randomly selected patients with chronic active type B hepatitis, aged 7-59 years, were assigned to treatment. All the patients had been treated for several months to several years with steroids, with no beneficial effect--clinical and biochemical symptoms of active liver disease, with histopathological progression (up to liver cirrhosis) had been permanently present. Treatment with leuHuIFN alpha (ldou) (doses: 50-100 U daily) was introduced immediately after the immunosuppression (steroids, steroids+azathioprine) discontinuation, and its influence on the course of the disease was monitored by means of hematological and biochemical tests, humoral and cellular immune response parameters, serological markers of HBV infection, HBV DNA concentration and immunohistochemical evaluation of liver biopsy specimens. The observation period ranges from 15 to 32 months. In all patients, within the first 3-6 weeks of treatment, transient deterioration of biochemical liver function tests was noted (e.g. 2-3 fold increase of ALAT), with no clinical symptoms of the disease exacerbation. The phenomenon lasted for 4-16 weeks. In all the treated patients, intensive immune system activation was seen, which lasted beyond the therapy period. Seven patients eliminated serum HBV DNA; all of them also eliminated HBeAg and seroconverted to HBeAb. Up to date, one person have lost serum HBsAg, in nine others its titre decreased significantly.

Administration, Oral↗

PubMed1993

Treatment of six patients with chronic active HCV hepatitis, with low dose natural human interferon alpha administered orally.

Following the widely accepted therapeutic standard of treatment of HCV infection with parenteral interferon alpha, and encouraged by the author's won good experience with orally administered natural human interferon alpha in low doses (leuHuIFN alpha (ldou)), applied to chronic active HBV hepatitis patients, this form of interferon was given to six randomly selected HCV infected patients (2 women, 4 men) aged 34-62 years. The diagnosis was made based on a clinical and histological evaluation and confirmed by anti-HCV antibodies detection. In 2 out of 6 patients, leuHuIFN alpha (ldou) was employed immediately after steroid discontinuation. Patients were instructed to take one lozenge daily, in the morning, on an empty stomach, and keep it in the mouth until fully dissolved. Observation period varies from 19 to 69 weeks. In 3 patients the therapy concluded, after 19, 61 and 62 weeks, respectively. One patient after 4 weeks of treatment reported increasingly troublesome small joints pain and swelling, which forced leuHuIFN alpha (ldou) discontinuation after 19 weeks. In no patient transaminases normalization was seen during treatment; biochemical and clinical remission after the drug discontinuation was observed in only one patient, in whom the treatment was interrupted due to articular adverse symptoms. With HCV RNA levels assessment being unavailable at the moment, the treatment impact on the virus replication remains difficult to evaluate objectively. The treatment was well tolerated. All patients stressed significant increase of drive and appetite as well as improvement of the exercise tolerance.

Administration, Oral↗

PubMed1992

Effect of angiotensin II and eledoisin on cholinergic neurons in rat hippocampus.

Angiotensin II and eledoisin modulate drinking behaviour in rats that is mediated by monoaminergic and cholinergic neurons. In the present study we have shown that combined intracerebroventricular injections of either 0.1 or 1.0 microgram doses of angiotensin and eledoisin resulted in a decrease of about 25-35% in activities of choline acetyltransferase, ATP-citrate lyase in the hippocampus. In addition, 1 microgram quantities of these peptides depressed activity of carnitine acetyltransferase but did not alter activity of acetylcholinesterase. On the other hand, the application of 0.1 microgram of angiotensin caused no change in activity of monoamine oxidase A, while 1.0 microgram dose brought about its 67% activation. Eledoisin abolished this effect of angiotensin II. These data provide evidence that angiotensin II and eledoisin evoke non related adaptive changes in cholinergic and monoaminergic neurons of the hippocampus.

Acetylcholinesterase↗

PubMed1991

Differential effects of angiotensin II and eledoisin on monoamine oxidase A and B activities in rat brain.

Intracerebroventricular injections of angiotensin II caused 108, 62, and 54% increases in monoamine oxidase A activities in rat hippocampus, hypothalamus, and striatum, respectively. These activatory effects were abolished by simultaneous injections of eledoisin. No significant changes of monoamine oxidase B activities were found under the same experimental conditions. Neither angiotensin II nor elodoisin changed substrate/inhibitor affinities of both isoenzymes. These data indicate that angiotensin II and tachykinin transmitter systems may exert opposite, long-term regulatory effects on monoaminergic neurons in rat brain.

Angiotensin II↗

PubMed1989

Modification of substrate-inhibitor affinities of human platelet monoamine oxidase B in vitro.

The rate of benzylamine utilization by monoamine oxidase (MAO)-B from human blood platelets was 2-4 times higher than that for octopamine. Both activities were inhibited 100% by 10(-7) M deprenyl (a specific MAO-B inhibitor) and were not affected by clorgyline (a specific MAO-A inhibitor) or by polyclonal antibodies to MAO-A. The preincubation of platelet MAO-B with purified MAO-A from mitochondrial membranes of human placenta resulted in appearance of excess octopamine activity. This additional activity was not precipitated by antibodies to MAO-A or inhibited by deprenyl but was inhibited by clorgyline. Incubation of the MAO-A preparation from placenta at 45 degrees C for 15 min before its preincubation with MAO-B caused 50% loss of both activities. Protease inhibitors had no effect on the modification of MAO. These data indicate that MAO-A or a factor tightly bound to it can modify MAO-B yielding a form of the enzyme with both MAO-A and MAO-B substrate and inhibitor affinities and MAO-B immunospecificity.

Antibodies↗

PubMed1989

Evidence for the regulatory function of synaptoplasmic acetyl-CoA in acetylcholine synthesis in nerve endings.

Isolated synaptosomes maintained a relatively stable level of acetyl-CoA during their incubation in the presence of 30 mM-KCl. Addition of Ca2+ resulted in inhibition of pyruvate oxidation and slight activation of acetylcholine synthesis. The cation decreased acetyl-CoA in intrasynaptosomal mitochondria, but did not alter its content in synaptoplasm. Verapamil did not affect pyruvate oxidation, but decreased acetyl-CoA in synaptoplasm and inhibited acetylcholine synthesis in synaptosomes. It indicates that Ca2+ might regulate acetylcholine synthesis through changes in the direct transfer of acetyl-CoA from mitochondria to synaptoplasm.

Acetyl Coenzyme A↗

PubMed1987

Elimination of CoASH interference from acetyl-CoA cycling assay by maleic anhydride.

A method for the removal of CoASH from tissue extracts by maleic anhydride is described. It eliminates CoASH interference in the acetyl-CoA cycling assay using phosphotransacetylase and citrate synthase. Maleyl-CoA thioether does not hydrolyze under the conditions of the assay and allows a reduction in the number of blank samples during acetyl-CoA determination. The levels of acetyl-CoA in whole rat brain, isolated synaptosomes, and mitochondria were found to be 61, 8.6, and 31.3 pmol/mg of protein, respectively.

Acetyl Coenzyme A↗

PubMed1987

Acid alpha-naphthyl acetate esterase assay in murine lymphocytes.

Acid alpha-naphthyl acetate esterase (ANAE) activity was assayed in cell homogenates and in intact cells by an endpoint colorimetric method, in which sodium dodecyl sulfate was used to stop the reaction. Each method of cell disruption and enzyme solubilization tested here caused a partial loss of the ANAE activity in lymphocyte preparations. The majority of the ANAE activity in lymphocytes was found to be membrane bound. The ANAE activity in thymocytes was over two times lower than that obtained for lymph node and spleen lymphocytes. Macrophages were found to contain about 18 times higher ANAE activity than mature lymphocytes.

Animals↗

PubMed1986

Purification of human blood platelet monoamine oxidase.

Monoamine oxidase B has been purified from human blood platelets 185-fold to a specific activity of 113 nmole/min/mg protein by a combination of Triton X-100 solubilization and ion exchange chromatography. A protein fraction corresponding to 58,000 Da on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was identified as monoamine oxidase by its ability to bind [3H]Pargyline.

Blood Platelets↗

PubMed1986

Synthesis of glutamate and aspartate in rat brain synaptosomes.

ATP and glutamine are the sources of endogenous ammonia in rat brain synaptosomes. The amount of endogenous ammonia formed from exogenous ATP is not sufficient to assure the maximum rate of aspartate and glutamate accumulation in the synaptosomes utilizing pyruvate + malate. Addition of exogenous NH4+ or depolarization of synaptosome plasma membranes with high K+ concentration led to a twofold increase in the rate of accumulation of these amino acids. This indicates that both exogenous and endogenous NH4+ is involved in the synthesis of aspartate and glutamate in nerve terminals. Accumulation of glutamate was stimulated by aminooxyacetate and inhibited by haloperidol which indicates that NH4+ is bound in the reaction catalysed by glutamate dehydrogenase. Endogenous oxaloacetate derived from pyruvate metabolism was the substrate for synthesis of aspartate. Additive inhibition of aspartate accumulation by fluorocitrate and (-) hydroxyacetate shows that, in addition to the tricarboxylic acid cycle, the reaction catalysed by ATP-citrate lyase serves in the synaptosomes as another source of oxaloacetate.

Adenosine Triphosphate↗

PubMed1984

Colorimetric assay for monoamine oxidase in tissues using peroxidase and 2,2'-azinodi(3-ethylbenzthiazoline-6-sulfonic acid) as chromogen.

Monoamine oxidase is assayed in tissue by a colorimetric reaction using horse radish peroxidase and 2,2'-azinodi(ethylbenzthiazoline-6-sulfonic acid to measure H2O2 formed during oxidation of amines. The method has a coefficient of variation of approximately 2.5% and provides results comparable with those of radiometric assay. Monoamine oxidase activities in rat liver mitochondria and crude mitochondrial fraction from brain and with tyramine as a substrate were 18.9 +/- 0.4 and 4.61 +/- 0.15 nmol/min/mg of protein, respectively, using this method. Kinetic parameters of liver and brain monoamine oxidase with various substrates and inhibitors appeared to be the same when determined by either colorimetric or radiometric methods.

Animals↗

PubMed1983

Purification and some properties of ATP-citrate lyase from rat brain.

ATP-citrate lyase has been purified from rat brain by a new procedure which yields an enzyme of specific activity of 21 U/mg protein (37 degrees C) (2050-fold purification). Purity (by sodium dodecyl sulfate-gel electrophoresis) of the preparation was comparable to that of rat liver ATP-citrate lyase of similar specific activity. Both brain and liver ATP-citrate lyase have the same electrophoretic mobility, as well as the same immunoreactivity against specific rabbit anti-rat liver ATP-citrate lyase antibody. These data indicate that rat brain ATP-citrate lyase is similar or identical to that present in rat liver. Intraperitoneally injected 32Pi was incorporated into the structural phosphate of ATP-citrate lyase in rat liver but not into the rat brain enzyme.

ATP Citrate (pro-S)-Lyase↗

PubMed1983

ATP-citrate lyase and other enzymes of acetyl-CoA metabolism in fractions of small and large synaptosomes from rat brain hippocampus and cerebellum.

The activities of choline acetyltransferase and ATP-citrate lyase were significantly correlated (r = 0.995) in fractions of small and large synaptosomes isolated from rat hippocampus and cerebellum. The activities of these two enzymes did not correlate with those of pyruvate dehydrogenase, carnitine acetyltransferase, citrate synthase, acetyl-CoA synthetase, lactate dehydrogenase, or with the rate of high-affinity glutamate uptake in the synaptosomal fractions. The results provide additional evidence linking ATP-citrate lyase to the cholinergic system in the brain.

ATP Citrate (pro-S)-Lyase↗

PubMed1983

The enzymes of acetyl-CoA metabolism in differentiating cholinergic (s-20) and noncholinergic (NIE-115) neuroblastoma cells.

Dibutyryl cyclic AMP and butyrate inhibited growth of S-20 (cholinergic) and NIE-115 (adrenergic) neuroblastoma clones. Both these drugs resulted in a parallel increase of choline acetyltransferase and ATP-citrate lyase activities in S-20 neuroblastoma cells. On the other hand, the increase in tyrosine hydroxylase activity in NIE-115 caused by these drugs was not accompanied by a significant change in ATP-citrate lyase activity. Both dibutyryl cyclic AMP and butyrate caused a decrease in fatty acid synthetase activity in both cell lines. The activities of pyruvate dehydrogenase, citrate synthase, choline acetyltransferase, and lactate dehydrogenase in both S-20 and NIE-115 cells were not significantly influenced by the drugs. ATP-citrate lyases from S-20 and NIE-115 had similar kinetic and immunological properties, and their subunits had the same molecular weight as the rat liver enzyme. These data indicate that the differential regulation of ATP-citrate lyase activity in cholinergic and adrenergic cells does not result from the existence of different molecular forms of the enzyme in these cell lines. They also provide further evidence to support the hypothesis that ATP-citrate lyase activity increases during maturation of normal cholinergic neurons and decreases in noncholinergic cells of the brain.

ATP Citrate (pro-S)-Lyase↗

PubMed1982

ATP citrate lyase in cholinergic nerve endings.

The activity of ATP-citrate lyase in homogenates of five selected rat brain regions varied from 2.93 to 6.90 nmol/min/mg of protein in the following order: cerebellum less than hippocampus less than parietal cortex less than striatum less than medulla oblongata and that of the choline acetyltransferase from 0.15 to 2.08 nmol/min/mg of protein in cerebellum less than parietal cortex less than hippocampus = medulla oblongata less than striatum. No substantial differences were found in regional activities of lactate dehydrogenase, pyruvate dehydrogenase, citrate synthase or acetyl-CoA synthase. High values of relative specific activities for both choline acetyltransferase and ATP-citrate lyase were found in synaptosomal and synaptoplasmic fractions from regions with a high content of cholinergic nerve endings. There are significant correlations between these two enzyme activities in general cytocol (S3), synaptosomal (B) and synaptoplasmic (Bs) fractions from the different regions (r = 0.92-0.99). These data indicate that activity of ATP-citrate lyase in cholinergic neurons is several times higher than that present in glial and noncholinergic neuronal cells.

ATP Citrate (pro-S)-Lyase↗

PubMed1982

Effects of septal lesions on enzymes of acetyl-CoA metabolism in the cholinergic system of the rat hippocampus.

Electrolytic lesions made in the medial septum of the rat brain caused an 80% decrease in the activity of choline acetyltransferase and a 33% reduction in ATP-citrate lyase activity in the synaptosomal fraction from the hippocampus. Decreases in the activities of the two enzymes in the cytosol (S3) fraction were 70 and 13%, respectively. The activities of pyruvate dehydrogenase, citrate synthase, acetyl-CoA synthase, and carnitine acetyltransferase in crude hippocampal homogenates and in subcellular fractions were not affected by septal lesions. The data indicate that ATP-citrate lyase is linked to the septal-hippocampal pathway and that the enzyme is preferentially located in cholinergic nerve endings that terminate within the hippocampus.

ATP Citrate (pro-S)-Lyase↗