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A Paulin

Publications and source records attributed to A Paulin.

At least 19 recordsLinked to original sources
PubMed1993

Tissue-specific alterations in lipoprotein lipase activity in the rat after chronic infusion of isoproterenol.

This study describes the consequences of sustained exposure to the nonspecific beta adrenergic agonist isoproterenol on the activity of lipoprotein lipase (LPL) in tissues that are sites for a large portion of the intravascular hydrolysis of triacylglycerols. Chronic exposure to isoproterenol was accomplished by means of osmotic pump infusion during four consecutive days, and assessment of the activity of LPL was performed at the end of the treatment. Four days of ISO infusion resulted in a large decrease in LPL activity of parametrial white adipose tissue, which declined to half of that found in the untreated group. In contrast, brown adipose tissue LPL activity was greatly increased (approximately threefold) by ISO treatment. The beta agonist raised LPL activity in red vastus lateralis muscle by a factor of four over control values, whereas heart enzyme activity was not significantly altered by the drug. These results demonstrate that catecholamines are part of the factors which determine the tissue specificity of LPL regulation. The tissue-specific changes in enzyme activity in response to isoproterenol, which are in very good agreement with the known metabolic actions of catecholamines in adipose and skeletal muscle tissues, attest to the key role of the enzyme in the partitioning of lipid substrates in situations of increased sympathetic activity.

Adipose Tissue↗
PubMed1992

Serum free fatty acids are not involved in acute exercise-induced reduction of LPL in rat tissues.

The present studies were designed to verify whether preventing the rise in serum levels of nonesterified fatty acids (NEFA) by adrenergic blockade would interfere with the decrease in tissue lipoprotein lipase (LPL) activity caused by acute exercise in rats. Ninety minutes before being killed, male rats were injected intraperitoneally with either saline, the beta-adrenergic blocker propranolol (25 mg/kg body weight), or the alpha 2-adrenergic blocker yohimbine (3 mg/kg body weight). Half of each group was killed at rest and the other half immediately after a 1-h run on a treadmill. LPL was determined in white adipose tissue (WAT), heart, and red vastus lateralis muscle (VLM). Exercise enhanced serum levels of NEFA 50% over resting values in saline-injected rats. The latter increase was totally abolished in animals having received propranolol or yohimbine. The activity of LPL in WAT, heart, and red VLM was approximately 35% lower in exercised rats than in resting animals. Serum triacylglycerols were also reduced by the run. Neither propranolol nor yohimbine interfered with any of these reductions. Exercise did not change serum glucose levels in saline-injected rats but decreased it in those injected with propranolol or yohimbine. Serum insulin was unchanged by exercise and by the antagonists. These findings suggest that the beta- and alpha 2-adrenergic pathways, as well as the exercise-induced rise in serum levels of NEFA, are not responsible for the early reducing effect of a 1-h run on tissue LPL activity in untrained rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Acute effects of exercise on triacylglycerol metabolism in fasted, untrained rats treated with nadolol.

The current study investigated the early response of some determinants of triacylglycerol (TG) metabolism to acute exercise in rats that were treated or not with the nonselective beta-adrenergic blocker, nadolol (25 mg.kg b.wt.-1.day-1 for 30 days). Measurements of hepatic TG secretion rate (HTGSR), postheparin plasma hepatic TG lipase (HTGL) activity, and that of lipoprotein lipase (LPL) in postheparin plasma, heart, vastus lateralis muscle (VLM), white (WAT) and brown (BAT) adipose tissues were carried out in untrained rats at rest or immediately after a 1 h run on treadmill (22 m.min-1, 0 degrees grade). All animals were in the fasted state. Exercise reduced serum TG levels (46% below resting levels) and doubled those of nonesterified fatty acids. HTGSR was enhanced (+28%) by exercise while HTGL activity was not modified. The decrease in postheparin plasma LPL activity (-24%) caused by exercise was consistent with a reduction in enzyme activity in WAT (-32%), BAT (-45%) and heart (-25%). One h of treadmill running did not influence LPL activity in VLM. beta-Adrenergic blockade did not affect any of the variables of lipid metabolism, except for a slight decrease in specific activity of LPL in the heart (-14%). This study demonstrates that absolute variations in HTGSR and in LPL activity cannot account for the acute fall in serum TG levels caused by moderate exercise, in fasted, untrained rats. In addition, these results show that the beta-adrenergic pathway is either not involved in, or not necessary for, the latter effects of exercise on TG metabolism.

Animals↗
PubMed1991

Restoration of lipoprotein lipase activity in insulin-deficient rats by insulin infusion is tissue-specific.

The activity of lipoprotein lipase was measured in white and brown adipose tissues, red vastus lateralis muscle, and heart of rats that have been insulin deficient (streptozotocin, 75 mg.kg-1) for 2 weeks, and that have then received implants of insulin-delivering minipumps (17 U.kg-1.day-1) for 1 or 4 days. Normal glycemia was restored in insulin-deficient animals after 4 days of insulin treatment. Hypertriglyceridemia, but not hypercholesterolemia, was reversed after 4 days of insulin infusion. After 2 weeks of insulin deficiency, fasting lipoprotein lipase activity was lowered in all tissues studied. In white adipose tissue, lipoprotein lipase decreased to 50% of control values. After a single day of insulin infusion, even if tissue weight has not yet been greatly affected, total activity was completely restored to control levels. Enzyme activity in brown adipose tissue was also depressed in deficient animals, and insulin infusion was followed by a slow recovery of activity, to a level intermediate between those of control and insulin-deficient groups. Insulin status had milder effects on lipoprotein lipase activity in vastus lateralis muscle than in the adipose tissues. Deficient rats displayed 60% less activity than controls, and 4 days of hormone infusion only partially restored enzyme activity. There was a large loss of lipoprotein lipase in the heart following 2 weeks of insulin depletion, which was not counteracted by hormone infusion. Thus the speed and extent of recovery of lipoprotein lipase activity following hormone replacement in insulin-deficient animals varied widely among tissues. These findings suggest that insulin is part of the factors that determine the tissue specificity of lipoprotein lipase regulation.

Adipose Tissue↗
PubMed1991

Beta-adrenergic blockade and lipoprotein lipase activity in rat tissues after acute exercise.

The present experiments were aimed at evaluating the acute effects of exercise on lipoprotein lipase (LPL) activity in untrained rats. The activity of LPL was measured in postheparin plasma (PHP) before and at various times after a 1-h run on a treadmill (22 m/min, O degrees grade). LPL in PHP was 50% below pre-exercise levels immediately and 3 h after the run but was increased 65% over resting levels 24 h postexercise. To further characterize the very early fall in LPL activity in response to exercise and to assess the possible involvement therein of the beta-adrenergic pathway, LPL in heart, vastus lateralis muscle (VLM), and white (WAT) and brown (BAT) adipose tissues was determined at rest and immediately after exercise in rats that were treated or not with nadolol (25 mg.kg-1.day-1 for 30 days). Immediately after 1 h of exercise, there was a reduction in total enzyme activity in WAT (40% below resting levels), BAT (-58%), VLM (-53%), and heart (-30%). Exercise reduced serum triacylglycerol levels (-64%) and doubled those of nonesterified fatty acids. beta-Adrenergic blockade did not affect any of these variables. Both exercise and nadolol lowered serum cholesterol levels by approximately 20%, but the effects were not additive. These results show that the global intravascular pool of LPL undergoes divergent, time-dependent alterations in response to a single bout of moderate exercise. The acute downregulation of postheparin plasma LPL immediately after exercise reflected a fall in the total enzyme pool of all tissues studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1990

Isozymes of Superoxide Dismutase in Mitochondria and Peroxisomes Isolated from Petals of Carnation (Dianthus caryophyllus) during Senescence.

The balance between reactions involving free radicals and processes which ameliorate their effect plays an important role in the regulation of plant senescence. In this study a method was developed to isolate peroxisomes and mitochondria from carnation (Dianthus caryophyllus L. cv Ember) petals. Based on electron microscopy and marker enzyme levels, the proportion of peroxisomes to mitochondria increases during senescence. The superoxide dismutase (SOD) content of these fractions was examined. Mitochondria and peroxisomes were shown to contain two electrophoretically distinct SODs, a manganese-, and an ironcontaining SOD. The Mn- and Fe-SOD were found to have relative molecular weights of 75,000 and 48,000 and isoelectric points of 4.85 and 5.00, respectively. The presence of a Fe-SOD in mitochondria and peroxisomes is unique because this enzyme is usually located in chloroplasts. The activity of these two isoenzymes decreased during senescence in mitochondria but remained high in peroxisomes from senescent tissue. It is suggested that peroxisomes play a particular role in the process of senescence.

Journal Article↗
PubMed1989

Identification of different classes of superoxide dismutase in carnation petals.

Isoelectric focusing and nondenaturing two-dimensional electrophoresis, followed by an enzymatic characterization involving use of specific inhibitors were applied to identify the different forms of the superoxide dismutase (SOD) extracted from petals of cut carnation. Electrophoresis was carried out either with the crude extract or with fractions obtained after ion exchange chromatography of the extract. Three forms of the SOD were identified (Cu,Zn-SOD, Fe-SOD and Mn-SOD). They have close pI's (4.7 to 4.9) and most of them are composed of several isoforms.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1989

Effect of hepatic vagotomy on postexercise substrate levels in food-restricted rats.

The metabolic effects of a selective hepatic vagotomy (HV) were investigated at rest and immediately after a 50-min exercise period (26 m/min, 0% grade) in rats subjected to an overnight 50% food restriction. This dietary restriction reduced liver glycogen content to 50% of normal resting concentrations (2.2-2.8 g/100 g). No significant differences between HV and sham-operated rats were found in resting and exercising beta-hydroxybutyrate, glucose, glycerol, and insulin concentrations. Postexercise liver glycogen concentrations were reduced to approximately 1.0 g/100 g in both HV and sham-operated groups. This decrease was associated with significantly (P less than 0.01) lower postexercise glycogen levels in the soleus muscle of HV rats (2.6 times) along with higher plasma free fatty acid concentrations (P less than 0.01). These data provide evidence that HV combined with a progressive decrease in liver glycogen content may influence substrate regulation during exercise. They also support the concept of the existence of hepatic glucoreceptors responsive to a decrease in liver glycogen content.

Animals↗
PubMed1988

Effect of selective hepatic vagotomy on plasma FFA levels in resting and exercising rats.

Metabolic effects of a selective hepatic vagotomy (HV) were investigated in nonfasted (N) and 24-h fasted (F) rats, at rest and immediately after a 50-min exercise period (26 m/min, 0% grade). In nonfasted rats, no significant differences between HV and sham-operated (SHM) groups were found in blood substrates [free fatty acids (FFA) or glucose], insulin, and muscle glycogen levels, either at rest or after exercise. In F rats, liver glycogen was almost completely depleted at rest. This depletion was associated with a significantly (P less than 0.05) lower plasma FFA concentration at rest in HV compared with SHM rats (mean +/- SE, 0.57 +/- 0.04 vs. 0.83 +/- 0.1 mmol/l). No differences in FFA levels were observed between the same two groups after the exercise period. Exercise, however, resulted in a 2.5 times greater glycogen breakdown in the soleus muscle of HV compared with SHM rats. Hepatic vagotomy in the F condition was also associated with lower resting and exercising insulin concentrations. It is concluded that HV, when followed by a 24-h fast, may influence metabolic substrate regulation at rest and to a certain extent during exercise. These data support the concept of the existence of hepatic glucoreceptors responsive to a decrease in liver glycogen content.

Animals↗
PubMedDate not supplied

[Comparison of amoxicillin and amoxiclav in the therapy of respiratory infections].

Randomly hospitalized patients with respiratory tract infections admitted to three pulmonary departments of the Golnik Institute for Pulmonary Diseases and Tuberculosis were enrolled in an open, comparative clinical study of Amoksiklav and Amoxicillin. A group of 26 patients with a mean age of 64.5 years presenting with pneumonia (13), exacerbation of chronic bronchitis (12) and bronchiectasis (1) were given Amoskilav, while another 20 patients with a mean age of 61.4 years presenting with pneumonia (9), exacerbation of chronic bronchitis (5), bronchiectasis (5) and sinusitis (1) received Amoxicillin. The efficacy of treatment was assessed by bacteriological findings of respiratory tract specimens, sputum and blood leucocytosis, macroscopic purulence of sputum and the presence of fever. The bacteriological findings are shown in detail. Leucocytosis and macroscopic purulence of sputum significantly improved on Amoksiklav therapy (p less than 0.05) while with Amoxicillin there was no significant improvement. With respect to the presence of fever, there was no significant difference between Amoksiklav and Amoxicillin. The overall clinical and bacteriological response was very good and good in 88.5% of patients treated with Amoksiklav compared to 75% of those receiving Amoxicillin. Additionally, 1000 pathogenic strains were tested for their response to Amoksiklav and Amoxicillin. Amoksiklav proved superior against strains of Branhamella catarrhalis, E. coli, coagulase-negative staphylococci and K. pneumoniae (p less than 0.01).

Amoxicillin↗