SNPs within CHRNA5-A3-B4 and CYP2A6/B6 are associated with smoking dependence but not with tobacco dependence treatment outcomes in the Czech population.

PURPOSE: Tobacco/nicotine dependence has a significant heritable component. Genome-wide association studies have associated the single nucleotide polymorphisms (SNPs) rs578776, rs16969968, rs6474412, rs3733829 and rs4105144 with nicotine dependence in Western European populations. We examined whether these SNPs influence nicotine dependence and successful treatment of tobacco dependence in the Czech middle-European population. MATERIALS AND METHODS: Variants were analysed by PCR-RFLP or by TaqMan assay in 807 adult heavy tobacco-dependent smokers - patients of the Centre for Treatment of Tobacco Dependence (Prague) as well as 1,362 self-reported non-smokers. RESULTS AND DISCUSSION: Except for rs3733829, association with tobacco dependence was confirmed for all other genetic variants. In agreement with previous studies, the strongest determinant of tobacco dependence was rs16969968 with OR (95%CI) 1.32 (1.08-1.62) for A allele carriers vs. GG comparison (P=0.003). In contrast, none of the analysed variants reached significance with respect to a 1-year course of successful tobacco dependence treatment (all P over 0.18) in a subset of 525 patients. CONCLUSION: We confirmed the association between variants within genes that code nicotinic-acetylcholine receptors (-A3, -A5 and -B3), CYP2A6/B6 and tobacco dependence development in the Czech population. The success of the tobacco dependence treatment was not influenced by the analysed SNPs.

No change in serum incretins levels but rise of leptin levels after smoking cessation: a pilot study.

The mechanisms behind the changes of body weight after smoking cessation are only partially understood. To this end, we explored the possible effects of smoking cessation on incretin hormones, leptin and selected anthropometric, biochemical and other hormonal parameters. Twenty-two non-obese male adult smokers attending an ambulatory smoking cessation program in Prague, Czech Republic, were examined at the baseline. Thirteen patients (mean age 37.92+/-2.66 years, mean body mass index 25.56+/-0.69 kg/m(2)) successfully quit smoking and were examined three months after smoking cessation; relapsed smokers were not followed up. The patients underwent 2-h liquid meal test with Fresubin and repeated blood sampling for measurements of blood glucose, gastric inhibitory polypeptide (GIP), glucagon-like peptide 1 (GLP-1), amylin, insulin, leptin, peptide-YY (PYY) and pancreatic polypeptide (PP). Three months after smoking cessation, body weight increased (4.35+/-3.32 kg, p<0.001). Leptin levels increased significantly in all repeated samples, while levels of GIP, GLP-1, amylin, insulin, PYY and PP remained unchanged. In conclusions, smoking cessation increased leptin levels probably owing to weight gain while it did not influence incretin levels.

[The behavioral risk factors for contracting HIV infection in the intravenous administration of narcotics in abusers of psychoactive substances in the city of Rostov-on-Don]. / Povedencheskie faktory riska zarazheniia VICh-infektsiei pri vnutrivennom vvedenii narkotikov u potrebitelei psikhoaktivnykh veshchestv g. Rostova-na-Donu.

150 persons (drug users) who had applied to the department of psycho-social consultations and voluntary tests for the presence of HIV infection and STD of the Regional AIDS Control Center, as well as partners of HIV-infected addicts in the intravenous use of drugs, were examined. Out of 150 examined persons 63 were found to be positive for HIV infection. Among dangerous behavioral patterns, characteristic of drug addicts introducing drugs intravenously, the practice of repeated aspiration of the drug into syringes from the dose of the drug solution, common for the whole group of addicts, was noted as the most widespread habit.

Phospholipids with a short acyl chain modulate phospholipase and acyltransferase activities.

1-Acyl lysophosphatidylcholine prepared from egg yolk has been chemically reacylated to form decanoyl, dodecanoyl, myristoyl and palmitoyl derivatives of phosphatidylcholine. The liposomes formed by these semi-synthetic phospholipids have been characterized by calorimetry, X-ray diffraction and fluorescence probe methods. Asymmetric phosphatidylcholines tend to promote formation of excimers of a codispersed fluorescent phospholipid (1-palmitoyl-sn-2-(1-pyrenedecanoyl)-L-alpha-phosphatidic acid) (2 mol%). Excimer formation is correlated with the rate of hydrolysis of the fluorescent anionic phospholipid by Crotalus venom phospholipase A2. Codispersion with the semi-synthetic phosphatidylcholine of cholesterol or unsaturated fluid lecithin modulated both excimer formation and the susceptibility of the fluorescent probe to hydrolysis by venom phospholipase A2 at 22 degrees C. Similar results were obtained with hydrolysis of a radiolabelled substrate, 1-palmitoyl-sn-2-[1-14C]linoleoylphosphatidylethanolamine, codispersed with the semi-synthetic phosphatidylcholine. Enrichment of rat hepatocyte plasma membranes with semi-synthetic asymmetric phosphatidylcholines was mediated by incubation of membranes with phospholipid dispersions in the presence of a phospholipid exchange protein. Enrichment of the membranes with semi-synthetic phosphatidylcholines of between 30 and 60% of the membrane phosphatidylcholine was achieved. The resulting alteration of the biomembrane is associated with a decreased activity of endogenous membrane phospholipase A2 acting on extramembranous radiolabelled substrate vesicles. By contrast, the activity of acyl-CoA:lysophospholipid acyltransferase is increased in membranes enriched with highly asymmetric phospholipids.

Acyl-CoA synthetase activity depends on the phospholipid composition of rat liver plasma membranes.

The dependence of acyl-CoA synthetase on the lipid composition of rat liver plasma membranes has been investigated. For this purpose the composition of the membranes was modified by incorporation of different phospholipids in the presence of partially purified lipid transfer proteins. Another approach to the modification of the membrane phospholipid composition was treatment with exogenous phospholipase C and subsequent enrichment with different phospholipids. The experiments performed in vitro indicated that the presence of certain phospholipids such as phosphatidylnositol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine was essential for the activation of long chain fatty acids by acyl-CoA synthetase. However, some differences were observed when oleate and palmitate were used as substrates. Sphingomyelin was found to inhibit this activity especially when oleic acid served as substrate. In addition, we tried to modify in vivo the membrane lipid composition by treatment with D-galactosamine, which is known to induce acute hepatitis and cause biochemical and biophysical alterations in liver membranes. The results thus obtained confirmed the idea that the augmentation of the membrane lipids and especially of PI, PE and PG was accompanied by acyl-CoA synthetase activation. The presence of two different enzymes, activating the saturated and unsaturated fatty acids is discussed.

A novel acidic form of the phosphatidylinositol transfer protein is preferentially retained in permeabilized Swiss mouse 3T3 fibroblasts.

By use of indirect immunofluorescence it was shown that phophatidylinositol transfer protein (PI-TP) remains associated with the Golgi system of Swiss mouse 3T3 fibroblasts after permeabilization with streptolysin O. By Western blot analysis it was demonstrated that intact cells contain the phosphatidylinositol-bound form of PI-TP (pI 5.5) and a novel more acidic form of PI-TP (pI 5.4) in approximately equal amounts. After permeabilization, about 50% of the PI-TP was retained in the cells with an enrichment of the pH 5.4 form relative to the pH 5.5 form; the opposite was observed for the PI-TP released into the medium. Subfractionation of cell homogenates by centrifugation provided evidence that a distinct amount of PI-TP is strongly bound to the membrane fraction with the pH 5.4 form more prominently present than the pH 5.5 form.

Phospholipase C activities in rat liver plasma membranes depend on the phospholipid composition.

Investigations were carried out on the influence of rat liver plasma membranes phospholipid composition on phospholipase C activity using PIP, PIP2, PC and PE as substrates. The membrane phospholipids were modified by incorporation of definite phospholipids with the aid of lipid transfer proteins or after partial delipidation with exogenous phospholipases A2 and C. The results indicated that sphingomyelin inhibited all phospholipase C activities. The incorporation of two different molecular species of phosphatidylcholine did not alter significantly the investigated phospholipase C activities, indicating that membrane fluidity was not essential in this case. Phosphatidylglycerol, phosphatidylserine, phosphatidylinositol and phosphatidylethanolamine served as specific activators of plasma membrane-bound phospholipase C when PIP, PIP2 and PC were used as substrates. However, these four phospholipids inhibited phospholipase C activity towards PE. The role of phosphoinositide-specific phospholipase C in the production of second messengers as well as the eventual biological significance of PC and PE as substrates for phospholipase C is discussed.

Effect of membrane phospholipid composition and fluidity on rat liver plasma membrane tyrosine kinase activity.

1. The effect of membrane phospholipid composition and fluidity on tyrosine kinase activity was investigated in rat liver plasma membranes. 2. The phospholipid composition has been modified by in vitro enrichment of plasma membranes with different phospholipids in the presence of lipid transfer proteins and by partial delipidation with exogenous phospholipases A2, C and D and subsequent enrichment with phosphatidylglycerol. 3. Phosphatidylglycerol and dioleoylglycerophosphocholine caused dramatic elevation of this activity, while phosphatidylserine and phosphatidylethanolamine were less effective. Enrichment with dipalmitoylglycerophosphocholine and sphingomyeline reduced tyrosine kinase activity.

Phospholipid dependence of rat liver microsomal acyl:CoA synthetase and acyl-CoA:1-acyl-sn-glycero-3-phosphocholine O-acyltransferase.

Investigations were performed on the influence of the phospholipid composition and physicochemical properties of the rat liver microsomal membranes on acyl-CoA synthetase and acyl-CoA:1-acyl-sn-glycero-3-phosphocholine O-acyltransferase activities. The phospholipid composition of the membranes was modified by incubation with different phospholipids in the presence of lipid transfer proteins or by partial delipidation with exogenous phospholipase C and subsequent enrichment with phospholipids. The results indicated that the incorporation of phosphatidylglycerol, phosphatidylserine and phosphatidylethanolamine induced a marked activation of acyl-CoA synthetase for both substrates used--palmitic and oleic acids. Sphingomyelin occurred as specific inhibitor for this activity especially for palmitic acid. Palmitoyl-CoA: and oleoyl-CoA: 1-acyl-sn-glycero-3-phosphocholine acyltransferase activities were found to depend on the physical state of the membrane lipids. The alterations in the membrane physical state were estimated using two different fluorescent probes--1,6-diphenyl-1,3,5-hexatriene and pyrene. In all cases of membrane fluidization this activity was elevated. On the contrary, in more rigid membranes obtained by incorporation of sphingomyelin and dipalmitoylphosphatidylcholine, acyltransferase activity was reduced for both palmitoyl-CoA and oleoyl-CoA. We suggest a certain similarity in the way of regulation of membrane-bound acyltransferase and phospholipase A2 which both participate in the deacylation-reacylation cycle.

Phospholipid-dependence of rat liver plasma membrane protein kinase activities--a new approach.

The influence of the phospholipid composition and fluidity on protein kinase A and protein kinase C activities in rat liver plasma membranes was studied. We observed that enrichment of membranes with phosphatidylglycerol, phosphatidylserine, phosphatidylethanolamine and dioleoylphosphatidylcholine caused activation of both protein kinases. Phosphatidylglycerol was found to be most effective activator. The enrichment of plasma membranes with dipalmitoylphosphatidylcholine and sphingomyelin led to decrease in protein kinase A and C activities. The stimulatory effect of phosphatidylglycerol was confirmed in plasma membranes pretreated with exogenous phospholipases A2, C and D, and subsequently enriched with phosphatidylglycerol. We suggest that besides the specific presence of definite phospholipids protein kinases A and C require a more fluid membrane lipid bilayer to display an optimal activity.

Phospholipid dependence of phospholipase C in rat liver plasma membranes.

Investigations have been carried out on the lipid dependence of membrane-bound phosphatidylinositol-specific phospholipase C in rat liver plasma membranes. For this purpose the phospholipid composition of rat liver plasma membranes has been modified in two different ways. The first method included enrichment of plasma membranes with different phospholipids in the presence of lipid transfer proteins, and the second a partial delipidation by means of exogenous phospholipases A2 and C and selective enrichment with different phospholipids. The results indicated that almost all used phospholipids induced activation of phosphatidylinositol-specific phospholipase C except sphingomyelin. Phosphatidylethanolamine and egg yolk phosphatidylcholine were observed to be most effective in phospholipase C activation.

Acyl-CoA: 1-acyl-glycero-3-phosphoethanolamine O-acyltransferase and liver plasma membrane fluidity.

Investigations have been carried out on the influence of membrane lipid composition and physical state on acyl-CoA: 1-acyl-glycerol-3-phosphoethanolamine O-acyltransferase activity in rat liver plasma membranes. The lipid composition of the membranes was modified either by way of lipid transfer proteins or by partial delipidation with exogenous phospholipases and subsequent enrichment of the membranes with different phospholipids. The results indicated that membrane rigidification by enrichment of the membranes with DPPC or SM reduced the transfer of oleic and palmitic acid to lysophosphatidylethanolamine, whereas all phospholipids inducing membrane fluidization lead to acyltransferase activation. The eventual role of membrane fluidity in the deacylation-reacylation cycle is discussed.

Insulin effect on the phospholipid organization and some enzyme activities of rat liver membrane fractions.

1. The influence of insulin on rat liver membrane lipid composition, fluidity, some enzyme activities and asymmetry of microsomal phospholipids were investigated. 2. The total phospholipids and cholesterol were increased in microsomes and reduced in plasma membranes from insulin-treated rats. 3. Of all the investigated enzymes participating in the lipid metabolism, only the neutral sphingomyelinase activity was observed to be enhanced, whereas the ceramide-phosphatidylethanolamine (PE) synthetase and phospholipase A2 activities remained unchanged. 4. Insulin administration caused translocation of phosphatidylserine (PS) and PE to the outer leaflet and of phosphatidylinositol (PI) to the inner leaflet of microsomal membranes.

Membrane phospholipid composition, fluidity and phospholipase A2 activity of human hepatoma cell line HepG2.

1. Investigations have been carried out on the phospholipid composition, physical state and phospholipase A2 activity of plasma and microsomal membranes from HepG2 cells. 2. The results showed a great similarity in the physico-chemical properties of plasma and microsomal membranes from HepG2 cells. 3. The activity of phospholipase A2 was found to depend on the membrane physical state in both types of membranes.

Effect of probucol on the lipid composition of blood plasma, erythrocyte ghosts and liver membranes in mice.

1. Probucol treatment of mice (0.6 g/kg) induced a decrease of cholesterol (CH) and total phospholipids (PLs) in blood plasma, erythrocyte ghosts, liver plasma and microsomal membranes. 2. The incorporation of [14C]acetate in the microsomal lipids of probucol-treated mice was lowered by 23% compared to controls. 3. Probucol administration induced a reduced specific activity of PLs, CH and CH esters, whereas in triacylglycerols it was augmented. 4. Phospholipase A2 and neutral sphingomyelinase activities were not enhanced, indicating that the catabolism of the membrane PL was not elevated.

Influence of immobilization stress on the phospholipid composition of alveolar surfactant and lungs in rats.

The influence of immobilization stress on the lipid composition of alveolar surfactant and lungs in rats immobilized for 12 and 24 hours, the effects of phospholipase A2, and lipid transfer activity in alveolar surfactant were investigated. The results indicate that alveolar surfactant phospholipids underwent more significant alterations compared to lung phospholipids. Furthermore, phospholipase A2 and lipid transfer activity were reduced in alveolar surfactant of immobilized rats. The reported data suggest that the lower lipid transfer activity might be responsible for the reduced phospholipids in the surfactant system.

Age-related changes in rat liver phospholipid transfer activity.

The age-induced changes in the liver cytosol phospholipid transfer activity of male and female rats have been investigated. These changes were found to be closely related to the age-induced alterations in the two major microsomal phospholipids--phosphatidylcholine and phosphatidylethanolamine. Regression analysis indicated a linear correlation between the phospholipid transfer activity and the level of phosphatidylcholine (positive) and phosphatidylethanolamine (negative) in liver microsomes of both male and female rats.

[Changes in the reaction of rat bone tissue to hypokinesia after administration of hydroxymethyl aminopropylidene bisphosphonate]. / Izmenenie reaktsii kostnoi tkani krys na gipokineziiu pod vliianiem oksidimetilaminopropiliden bisfosfonata (AMOK).

During 35-day hypokinesia rat spongy bone in the tibia and vertebrae varied in two phases. The first phase (up to 15 days) was induced by a stress-reaction and the second phase by adaptation to hypokinesia. Under the influence of subcutaneous injections of hydroxydimethyl aminopropylidene biphosphonate (AMOK) at a dose of 0.01 mg/kg/day bone changes disappeared: throughout the study spongy bone mass remained as in controls. AMOK administration at a dose of 5 mg/kg/day 10 days prior to hypokinetic exposure did not eliminate its inhibitory effect although the initial bone mass was 1.5-2 times higher than in the controls. However at the adaptation phase (beginning with day 15) bone mass increased, reaching the baseline. This indicates a decline in bone sensitivity to muscle unloading. It is concluded that AMOK modifies bone responses to various hypokinetic factors.

[Effect of alpha-hydroxydimethyl-gamma-aminopropylidene bisphosphonate on the bone tissue of rats during hypokinesia]. / Vliianie alpha-oksidimetil-gamma-aminopropilidena bisfosfonata na kostnuiu tkan' krys pri gipokinezii.

The preventive effect of alpha-hydroxydimethyl-gamma-aminopropylidene bis-phosphonate was investigated histomorphometrically. The agent was injected subcutaneously to rats before hypokinesia at a dose of 5 mg/kg or during 35-day hypokinesia at a dose of 0.005 or 0.01 mg/kg daily. Regardless of the treatment protocol, the agent prevented osteoporosis and did not affect the epiphyseal growth plate. The agent modified significantly the bone cell count: osteoblasts decreased and osteoclasts increased. It is concluded that when compared to xydiphone (hydroxyethylidene bis-phosphoric acid), the agent proves several hundred times more effective. It is assumed that the agent modifies the relation between bone formation and bone resorption. Its osteotropic effect manifests as inhibition of bone resorption.

[Causes of primary disability of miners at the iron ore mining-processing plants]. / Prichiny pervichnogo vykhoda na invalidnost' gornorabochikh zhelezorudnykh gorno-obogatitel'nykh kombinatov.

Causes of primary invalidism of miners at an ore-dressing plant are presented. When analyzing the data, miners' occupation, age and length of service have been taken into account. Some preventive measures are set forth.