Nano, micro, and bulk structures in atactic polystyrene-syndiotactic polystyrene blends obtained in situ in presence of the CpTiCl3/SiO2/MAO catalysts (Cp-cyclopentadienyl, MAO-methylaluminoxane).

CpTiCl3/SiO2/MAO (Cp=cyclopentadienyl, MAO - methylaluminoxane) catalysts, where the Al:Ti varies from 20:1 to 500:1, were used in styrene polymerization. Atactic - syndiotactic polystyrene blends (aPS-sPS) were obtained in situ, the morphology of which was investigated by means of scanning electron microscopy. The blends morphology changed according to the kind of catalytic centers: cationic and syndiotactic on the catalyst surface, which create individually atactic or syndiotactic polystyrenes forming specific blends containing nano or micro-forms: when the Al:Ti ranges from 50:1 and to 100:1 in the blends, there occur nano-sPS particles 40-120 nm in size, if the Al:Ti≥300:1, the filament of δ-sPS polymorph, is produced where the filament size ranged from 30 to 10 nm. A decay of this form leads to the formation of spherical sPS forms several hundreds of nm in size. When the Al:Ti ranges 20:1-50:1, blend rods of several dozen micrometers were obtained.

Quantification of organic acids in particulate matter by coupling of thermally assisted hydrolysis and methylation with thermodesorption-gas chromatography-mass spectrometry.

A quantitative method for the determination of organic acids in atmospheric particles is developed. The method couples a derivatisation step (thermally assisted hydrolysis and methylation) and a Curie point pyrolyser as a thermal desorption technique and gas chromatography-mass spectrometry (CPP-GC-MS). Among the reagents tested (tetramethylammonium hydroxide (TMAH), tetramethylammonium acetate (TMAAc) and phenyltrimethylammonium hydroxide (TMPAH)), the best performance was found using TMAAc as a derivatisation reagent for the reaction time of 4s at 510 degrees C as heating temperature. Calibration was performed for a series of fatty acids (FA), dicarboxylic acids (DCA) and terpenoic acids (TA) under these conditions. Coefficients of determination (R(2)) were between 0.94 and 0.98. Limits of detection (LOD) were in the nanogram-range between 0.1 and 3.6 ng. The method is applied on atmospheric particle samples to obtain the quantification reproducibility and quantification limits. Reproducibility was determined in terms of relative standard deviations (RSD) for ambient aerosol samples collected by a high-volume-sampler (HVS, RSD=6-45%, n=10) and a Berner impactor (BI, RSD=5-34%, n=10). Based on 24h sampling time the developed method enables quantification of all three classes of acids for both sampling techniques. Calibration data and presented volume concentrations are compared with literature data. A comparison with an off-line methylation-GC-MS using BF(3) as a derivatisation reagent and capillary electrophoresis coupled mass spectrometry (CE-MS) showed a good agreement. Minimal sample preparation is the main advantage of the developed method. Depending on the sensitivity requirements the present method can be a fast and simple alternative to GC-MS techniques with conventional sample preparation steps for semi-volatile organic acids.

Glucose-6-phosphatase and age: biochemical and histochemical studies.

Glucose-6-phosphatase catalyzes the final reactions in both gluconeogenesis and glycolysis. It occurs mainly in glycogenic tissues, such as the liver, where it plays an important role in the synthesis of glucose, a carbohydrate essential for tissue functioning. The effect of age on liver glucose-6-phosphatase activity was evaluated in male Wistar rats treated with mixed function oxidase system (MFO) inducers. The rats were divided into the following age groups: 0.5, 1, 2, 4, 8, 12, 20 and 28 months of age. Glucose-6-phosphatase activity was evaluated biochemically and histochemically. Biochemical glucose-6-phosphatase activity increased up to the 20th month of rat life and then decreased rapidly. A similar tendency was observed in inducer-treated groups, though only dexamethasone stimulated this enzyme activity in all age groups studied. Histochemical glucose-6-phosphatase activity was strongest in the periportal zones. Glucose-6-phosphatase activity decreased significantly at month 8 and then it increased significantly until month 20. In the oldest age group, glucose-6-phosphatase activity decreased again. On histochemical analysis, the inducers used variably affected glucose-6-phosphatase activity.

Neoplastic lesions of the human liver in relation to the activity of the cytochrome P-450 dependent monooxygenase system.

We studied the activity of Mixed function oxidase (MFO) in human livers affected by cancer. We determined the content of cytochrome P-450 and b5, as well as the activity of their corresponding reductases, according to generally accepted methods. Liver fragments corresponding with a) healthy tissue, b) tissue at the cancer border and, c) cancerous tissue were collected during surgery from patients with liver cancer. We noted that the developing liver cancer decreased the level of cytochrome P-450, even by a magnitude order. The activity of its corresponding reductase was higher in cancerous than in healthy tissues. Cytochrome b5 behaved in an analogous manner, although the decrease in its content was less significant. NADH-cytochrome b5 reductase activity changes were insignificant.

Influence of acetaminophen and trichloroethylene on liver cytochrome P450-dependent monooxygenase system.

The aim of the study was to evaluate the effect of acetaminophen (APAP) and/or trichloroethylene (TRI) on the liver cytochrome P450-dependent monooxygenase system, CYP2E1 and CYP1A2 (two important P450 isoforms), and liver glutathione (GSH) content in rats. Rats were given three different doses of APAP (250, 500 and 1000 mg/kg b...) and then the above-mentioned parameters were measured for 48 h. The lowest APAP dose produced small changes in the cytochrome P450 content of liver. At 500 mg/kg APAP increased the cytochrome P450 content to 230% of the control. The inductive effect was seen at 1000 mg/kg dose but at 24 h and later. NADPH-cytochrome P450 reductase activity was the highest after the lowest dose of APAP, while after the highest dose it was equal to the control value. TRI increased both the cytochrome P450 content and the NADPH-cytochrome P450 reductase activity. When TRI was combined with APAP, both these parameters increased in the first hours of observation, but they returned to the control values at 24 h. When APAP was given at 250 mg/kg, GSH levels decreased to 55% of the control at 8 h and returned to the control values at 24 h. The higher doses of APAP decreased GSH levels more than the lowest dose, but after 24 h GSH levels did not differ from those of the control. When TRI was given at 250 mg/kg, the GSH levels decreased to 68% of the control at 2 h and then they increased gradually and tended to exceed the control values at 48 h. The effect of TRI combined with APAP on the level of GSH was virtually the same as that of APAP alone given at 500 mg/kg.

Ontogenesis of hepatocyte respiration processes in relation to rat liver cytochrome P450-dependent monooxygenase system.

The study aimed to evaluate the effect of age on the activity of the cytochrome P450-dependent monooxygenase system and on cellular respiration processes in Wistar rats aged 0.5, 1, 2, 4, 8, 12, 20, and 28 months. The following parameters were determined: cytochrome P450 content, cytochrome b5 content, NADPH-cytochrome P450 reductase activity, and NADH-cytochrome b5 reductase activity, succinate dehydrogenase (SDH) activity, and lactate dehydrogenase (LDH) activity. In the study, cytochrome P450 content increased in the first month of life, which was accompanied by increases in SDH and LDH activities. In the subsequent months, SDH activity decreased, whereas LDH activity increased to reach the maximum in month eight and then decreased. Cytochrome b5 content showed a decreasing tendency throughout the experiment. NADH-cytochrome b5 reductase activity showed only slight deviations in individual age groups.

Effect of enflurane on selected neuropeptides and marker enzymes in rabbit brain.

The aim of this study was to evaluate the effect of 5-, 15-, and 60-min enflurane anesthesia on the levels of Met-enkephalin, Leu-enkephalin and neuropeptide Y in discrete areas of the rabbit brain. We also evaluated the effect of enflurane anesthesia on energetic, transport and catabolic processes by measuring the activities of succinate dehydrogenase, magnesium-dependent adenosine triphosphatase and acid phosphatase in the rabbit striatum and hypothalamus. Induction of anesthesia (5 min) decreased Met-enkephalin levels in the hypothalamus and striatum, and increased them in the hippocampus and mesencephalon. Induction of anesthesia increased Leu-enkephalin levels in all brain areas studied, except for the striatum, and increased neuropeptide Y content in the hippocampus. 15- and 60-min enflurane anesthesia increased Met-enkephalin content in the hypothalamus and hippocampus. After 15- and 60-min anesthesia, and after cessation of anesthesia, Leu-enkephalin levels were increased in the hypothalamus and mesencephalon, and were decreased in the striatum and hippocampus. In the striatum, neuropeptide Y content was significantly decreased during anesthesia and after cessation of anesthesia. Histochemical analysis revealed that enflurane enhanced ATP production, catabolic processes, and the rates of exchange and transport of energetic substrates in the striatum and hypothalamus. In conclusion, enflurane affects the levels of Met, Leu-enkephalins and NPY in a manner depending on the duration of anesthesia and the brain structure. Compared with isoflurane , which was studied in our previous study enflurane produces stronger alterations in the activities of enzymatic marker in the rabbit brain. This suggests that enflurane may be less safe than isoflurane.

The influence of age and some inducers on UDP-glucuronyltransferase activity.

UDP-glucuronyltransferase (UDP-GT) activity was examined in male Wistar rats aged 0.5, 1, 2, 4, 8, 12, 20, and 28 months. The rats were treated with phenobarbital (75 mg/kg, 72 and 48 h before death), beta-naphthoflavone or dexamethasone (40 mg/kg and 20 mg/kg, respectively, for three days before death). Prior to decapitation the rats were fasted for 12 h. Hepatic microsomes were prepared according to the method of Dallner. UDP-GT activity was determined by the method of Burchell and Weatherill. p-Nitrophenol was used as an aglucone. UDP-GT activity decreased rapidly in the control rats aged from two weeks to four months. In the older control rats the activity tended to increase. Two-week-old rats treated with phenobarbital showed a slightly increased UDP-GT activity. In the older animals (up to one year) UDP-GT activity increased to 150% of the control value and stayed at this level in the remaining age groups. beta-Naphthoflavone was a more potent inducer of UDP-GT than phenobarbital. The activity of beta-naphthoflavone-induced UDP-GT was low in the youngest rats. It was about 180% in two-month-old rats and reached 260% of the control value in eight-month-old rats. Although the activity decreased in the older rats, it still exceeded 200%. Dexamethasone did not affect UDP-GT activity. Only in two-week-old and two-month-old rats did we observe a slight increase in the activity of UDP-GT.

Estradiol and progesterone release form biodegradable d,l-lactide and epsilon-caprolactone copolymer.

A study on the release of 17 beta-estradiol and progesterone from d,l-lactide and epsilon-caprolactone copolymer was performed. The copolymer was used in the form of microsphere, d,l-lactide content in the copolymer was 83%. It was found that nearly constant rate of hormone release during 100 days of experiment can be achieved by using this biodegradable material as a drug carrier.

Influence of cholesterol and protein diet on liver cytochrome P-450-dependent monooxygenase system in rats.

The influence of the cholesterol and protein diet on the mixed-function oxidases system activity and desaturation of fatty acids were examined. The phenobarbital innducibility of these parameters was analyzed too. Investigations were carried out on Wistar adult male rats. The animals were on the cholesterol (0.25%) and protein diet (32%) during 45 days. The cytochrome P-450 and cytochrome b5 contents, the NADPH-cytochrome P-450 reductase and NADH-cytochrome b5 reductase activities, aniline hydroxylase and 4-aminopyrine N-demethylase activities were measured in the hepatic microsomal fraction. In both sexes, the cholesterol diet decreased all the examined parameters with the exception of NADH-cytochrome b5 reductase activity. The protein diet did not change the examined enzyme activities or levels with the exception of induction of NADH-cytochrome b5 reductase and 4-aminopyrine N-demethylase activities. Simultaneous treatment with phenobarbital had heterogenous effect dependent on the type of diet and examined parameter.

Activity of liver cytochrome P-450-dependent monooxygenase system in morphine-dependent rats.

Young female Wistar rats were injected intraperitoneally with increasing doses of morphine (9-45 mg/kg b.w. twice a day) for 14 days. The activities of the cytochrome P-450-dependent monooxygenase system and microsomal electron transport chain I were determined. Long-term morphine treatment decreased significantly cytochrome P-450 content, while it did not affect microsomal electron transport chain I. A decrease in cytochrome b5 content was accompanied by a compensatory increase in the activity of NADH-cytochrome b5 reductase. Both 4-aminopyrine N-demethylase activity and aniline hydroxylase activity decreased after morphine treatment (48% and 70%, respectively, when compared with controls).

Effects of age, phenobarbital, beta-naphthoflavone and dexamethasone on rat hepatic delta-aminolevulinic acid synthase.

delta-Aminolevulinic acid synthase is a key enzyme leading to the synthesis of cytochrome P-450, a compound of the mixed function oxidase system. Because of this, we have studied the effects of both age and three typical mixed function oxidase system induces on this enzyme activity in male Wistar rats. Our results suggest that delta-aninolevulinic acid synthase activity in intact rats increases up to maturity and then decreases being, however, higher in the oldest animals than in the youngest. Phenobarbital affects delta-aminolevulinic acid synthase activity very characteristically. This activity is high in 4-week-old animals and then increases slightly until the twelfth month of life. Phenobarbital enzymic inducibility tends to decrease with age. In the beta-naphthoflavone groups, the profile of delta-aminolevulinic acid synthase activity looks like that in the control ones. Generally, beta-naphthoflavone is a weaker delta-aminolevulinic acid synthase inducer than phenobarbital, but it seems to induce delta-aminolevulinic acid synthase like dexamethasone, which, being a physiological inducer of the mixed function oxidase system, is also an inducer of delta-aminolevulinic acid synthase and this inducibility is closely connected with age.

The circadian rhythm in activity of the periodic acid Schiff reaction and of the Mg and Ca content in rat liver in relation to age and season of the year.

The experiments were carried out on male Wistar rats aged 6, 12 and 24 months, over the four seasons of the year. Analysis of the results obtained in all age groups disclosed that changes in activity of the p.a.S (periodic acid Schiff) reaction and in concentrations of Mg and Ca in the liver showed rhythmic oscillations with a period of 12 hours. The maximal p.a.S reaction activity and of Ca and Mg levels were generally found to coincide throughout all seasons and in all age groups. The rhythms of change in these parameters in 12- and 24-month-old rats showed a phase shift as compared to the 6-month-old animals.

[Effect of the cholesterol and protein diet on cytochrome P-450 dependent monooxygenase activity]. / Wplyw diety cholesterolowej i bialkowej na aktywnosc ukladu monooksygenaz zaleznych od cytochromu P-450.

The effect of cholesterol and protein diet on mixed-function oxidase activity and desaturation of fatty acids were studid as well as phenobarbital inducibility of those parameters. Investigations were carried out on Wistar adult male rats. The animals were on the cholesterol (0.25%) and protein (32%) diet for 45 days. Cytochrome P-450 and cytochrome b5 contents, NADPH-cytochrome P-450 reductase, NADH-cytochrome b5 reductase, aniline hydroxylase and 4-aminopyrine N-demethylase activities were measured in a hepatic microsomal fraction. The cholesterol diet exerted a negative effect on all parameters except NADH-cytohrom b5 reductase. The protein diet did not change the activity or levels of enzymes under study. The only exception applied to induction of NADH-cytochrome b5 reductase and 4-aminopyrine N-demethylase activities. Simultaneous treatment with phenobarbital had a heterogenous effect depending on the type of diet and parameters examined.

Changes in the male rat hepatic cytochrome P-450 level, heme oxygenase and delta-aminolevulinic acid synthase activities at various stages of life.

delta-Aminolevulinic acid synthase and heme oxygenase are closely functionally connected with the hepatic microsomal mixed function oxydase system. There is a wide range of changes in microsomal heme oxygenase activity, cytochrome P-450 level and mitochondrial delta-aminolevulinic acid synthase activity in rat livers at various stages of life. We tried to investigate the spontaneous phases of these enzymatic protein activities and the levels of cytochrome P-450 as a function of age. We noted that each of these proteins change their activity and level very characteristically during the rats' lifetime. However, correlations between heme oxygenase activity, delta-aminolevulinic acid synthase activity and cytochrome P-450 levels still need to be investigated to elucidate the mechanism of these connections.

[Induced modifications of liver cytochrome P-450 levels as a function of age in rats]. / Induktorowe modyfikacje poziomu watrobowego cytochromu P-450 w funkcji wieku szczura.

In this paper we showed age effect on hepatic level of cytochrome P-450. We discussed effects of inductors on this hemoprotein also. Cytochrome P-450 content increased to 1-month of life, but decreased to 4-month. In the oldest rats cytochrome P-450 increased again. Content of this hemoprotein was induced by phenobarbital and beta-naphthoflavone in all examined groups, especially strong in young animals. Induction effect of dexamethasone was observed in 4-20-month of life.

[Induced modification of liver NADPH-cytochrome P-450 activity and II microsomal electron transport chain as a function of age in rats]. / Induktorowe modyfikacje aktywnosci watrobowej reduktazy NADPH-cytochrom P-450 oraz II mikrosomalnego lancucha transportu elektronów w funkcji wieku szczura.

In this paper we showed age effect on NADPH-cytochrome P-450 reductase activity, cytochrome b5 and NADH-cytochrome b5 reductase from rat liver. We discussed effect of some I, II and III classes inductor also. Activity NADPH-cytochrome P-450 reductase softly decreased from 0.5-2-month of life, but in older groups gradually increased. In 28-month-old rats it was twice fold youngest. Phenobarbital and dexamethasone (without 28-month-old age rats) induced but beta-naphthoflavone inhibited activity of this reductase. Cytochrome b5 content softly decreased to 4-month of life. In older animals changed of this hemoprotein content were not observed. The examined inductors of monooxygenase system decreased cytochrome b5 level. NADH-cytochrome b5 reductase activity increased to 1-month of life, but in older group decreased. After 2-month changes of activity were very small only. Phenobarbital, beta-naphthoflavone and dexamethasone inhibited activity of this reductase.

Effects of age, phenobarbital, beta-naphthoflavone and dexamethasone on rat hepatic heme oxygenase.

There is a wide range of change in both microsomal heme oxygenase activity and cytochrome P-450 level in the livers of rats of various ages. We tried to investigate the phases of heme oxygenase activity, both spontaneous and caused by typical MFO inducers in the lifetime of the rat. Wistar male rats aged 0.5, 1, 2, 4, 8, 12, 20 and 28 months received phenobarbital (50 mg/kg) twice, 3 and 2 days before being killed. beta-Naphthoflavone and dexamethasone were given three times: 3, 2 and 1 day before decapitation 20 mg/kg and 10 mg/kg, respectively). The highest heme oxygenase activity is observed in intact 2-week-old animals (1.16 +/- 0.038 nM/h per mg protein). Before maturity this activity decreases slightly up to the 2nd month of life. Then it stabilizes and remains virtually unchanged till the 8th month of life (1.02 +/- 0.03). Afterwards HO activity tends to increase until the 28th month of life (1.10 +/- 0.06), but does not reach the level observed in the 2-week-old animals. We have found that some typical MFO inducers can modify HO activity. While phenobarbital stimulates HO activity only in premature animals (1.42 +/- 0.056; 1.30 +/- 0.059 and 1.13 +/- 0.035, respectively in 0.5-, 1- and 2-month-old animals), beta-naphthoflavone enhances HO activity in all the groups studied. Dexamethasone, as a physiological inducer of the MFO system, modifies HO activity very characteristically. It induces this activity until the 2nd month of life and then its inducibility appears to remain unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypothalamic, striatal and plasma leucine enkephalin level in two rat models of portal hypertension.

In two rat models of portal hypertension obtained by common bile duct obstruction or by partial portal vein ligation the hypothalamic level of leu-enkephalin was increased but striatal and plasma level of leu-enkephalin was unchanged. These results may be of importance for understanding some disturbance related to hepatic encephalopathy.

Circadian variation of mitochondrial succinic dehydrogenase and microsomal cytochrome P-450 dependent monooxygenase activity in the liver of sexually immature and mature rats.

The experiments were carried out on 60-day and 6-month old male Wistar rats within 48 h in one season of the year (autumn). Material was collected every four hours, beginning from 10:00 a.m. The present results indicate that the fluctuations of cytochrome P-450 content in liver microsomes in both age groups occurred in a 12 h rhythm with peaks at 10:00 and 22:00. Similarly, the activity fluctuations of NADPH-cytochrome c reductase showed the 12 h rhythm, with maximal values at 10:00 and 22:00, too. The cytochrome b5 content in a younger group of rats oscillated apparently in the 12 h rhythm with the maximal values at 06:00 and 18:00. The activity course of cytochrome b5 in 6-month-old rats revealed a 24 h rhythm and two maxima of the activity were found: the first one at 14:00 and the second one at 02:00. NADH-cytochrome b5 reductase in both age groups showed a 24 h rhythm, also the activity fluctuations of succinic dehydrogenase showed a tendency to 24-h rhythmicity, and the differences between minimal and maximal values were statistically insignificant. The results of our experiment have shown some correlations between the activity of microsomal system of mixed-function oxidases and mitochondrial respiratory enzyme.