Susceptibility to Degradation in Soil of Branched Polyesterurethane Blends with Polylactide and Starch

A very important method of reducing the amount of polymer waste in the environment is the introduction to the market of polymers susceptible to degradation under the influence of environmental factors. This paper presents the results of testing the susceptibility to degradation in soil of branched polyesterurethane (PUR) based on poly([R,S]-3-hydroxybutyrate) (R,S-PHB), modified with poly([D,L]-lactide) (PLA) and starch (St). Weight losses of samples and changes in surface morphology (SEM, OM and contact angle system) with simultaneously only slight changes in molecular weight (GPC), chemical structure (FTIR and ¹HNMR) and thermal properties (DSC) indicate that these materials are subject to enzymatic degradation caused by the presence of microorganisms in the soil. Chemical modification of branched polyesterurethanes with R,S-PHB and their physical blending with small amounts of PLA and St resulted in a slow but progressive degradation of the samples.

Ovocystatin Induced Changes in Expression of Alzheimer's Disease Relevant Proteins in APP/PS1 Transgenic Mice

Background: Ovocystatin is marked by structural and biological similarities to human cystatin C, which plays an important role in the course of neurodegenerative diseases. Recently, it has been shown that ovocystatin might prevent aging-related cognitive impairment in rats and reduce memory decline in an APP/PS1 mice model. Thus, this study aimed to assess the effect of ovocystatin on histopathological changes in APP/PS1 mice. Materials and methods: Ovocystatin was administered intraperitoneally for four weeks (40 μg/mouse) to 35-weeks-old transgenic (AD, n = 14) and wild type (NCAR, n = 15) mice (stock B6C3-Tg(APPswe, PSEN1dE9)85Dbo/Mmjax). A histopathological evaluation comprised antibodies directed against β-amyloid (1:400, SIG-39320-1000, Covance) and Tau (1:4000, AHB0042, Invitrogen). Three regions of the hippocampus— the dentate gyrus (DG) and the cornu ammonis (CA1 and CA3)—were analyzed by immunohistochemistry in each animal. All differences are expressed as percentage relative to the control group. Results: The main results showed that the percentage of immunoreactive area of β-amyloid, tau protein deposits in APP/PS1+ovCYS was decreased in DG, CA1, and CA3 regions compared with the APP/PS1 control, respectively (p < 0.05). Conclusions: Ovocystatin caused significant changes in the expression pattern of all investigated proteins in hippocampal tissues both in APP/PS1 and NCAR mice.

New therapeutic strategies for Alzheimer’s disease

Alzheimer’s disease (AD) described as a chronic and irreversible neurodegenerative disease remains the most common cause of dementia. Due to the aging of the population, the incurability of AD has become a growing problem of medicine in the 21stcentury. Current treatment is only symptomatic, providing minimal, temporary improvement in the patient’s cognitive function. This paper presents the latest trends in the search for effective pharmacotherapy capable of preventing or inhibiting AD progression. Since the exact pathogenesis of Alzheimer’s disease is not known, the main therapeutic strategies are based only on the following hypotheses: amyloid cascade, tau protein, oxidative stress, neuroinflammation and those associated with dysfunction of the cholinergic system as well as glutamatergic. Most of the compounds currently tested in clinical trials are targeted at pathological amyloid β (A β), which is considered the cause of neurodegeneration, according to the most widely described cascade theory. Most of the compounds currently tested in clinical trials are targeted at pathological amyloid β (Aβ), which is the main cause of neurodegeneration according to the widely described theory of the amyloid cascade. Attempts to fight the toxic Aβ are based on the following: immunotherapy (vaccines, monoclonal antibodies), compounds that inhibit its formation: γ-secretase inhibitors/modulators and β-secretase. Immunotherapy can also be us,ed to increase the clearance of hyperphosphorylated tau protein, the occurrence of which is another feature of Alzheimer’s disease. In addition to immunotherapy, anti-inflammatory, metabolic and neuroprotective compounds have been the subject of a number of studies. A range of symptomatic compounds that improve cognitive functions by compensating cholinergic, noradrenergic and glutamatergic signaling deficits have also been investigated in clinical trials.

Degradability of Polyurethanes and Their Blends with Polylactide, Chitosan and Starch

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCL_triol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).

Green jobs, definitional issues, and the employment of young people: An analysis of three European Union countries

This article considers intertwined issues relating to the green economy, protected areas, green jobs, and the Environmental Goods and Services Sector (EGSS). The article discusses the most common approaches towards greening economies, all these being based on the concept of sustainable development, and presents an analysis of how green jobs can be used to address the issue of unemployment among young people in Poland, the Czech Republic and Belgium. Data were compared for selected groups in the European Classification of Economic Activities (NACE). It is observed that in both Poland and Belgium around 15% of young people find their first employment in the green jobs sector, but in the Czech Republic, the proportion is far lower (1.83%). It is concluded that an increasing emphasis on building the green economy provides excellent employment opportunities for young people seeking their first job.

Predicted Studies of Branched and Cross-Linked Polyurethanes Based on Polyhydroxybutyrate with Polycaprolactone Triol in Soft Segments

The number of cross-links in the non-linear polyurethane structure is the basic factor affecting its properties. Selected properties of aliphatic polyurethanes with soft segments made of different amounts of polycaprolactonetriol, polycaprolactonediol and synthetic, telechelic poly([R,S]-3-hydroxybutyrate) were determined. On the basis of changes in polyurethane properties, the correlation between these properties and the construction of soft segments was found. The structure of polyurethanes, their morphology, hydrophilicity, thermal and mechanical properties were examined. These properties were changed linearly up to 15% content of polycaprolactonetriol in soft segments. A further increase in the amount of triol causes that these properties are mainly determined by the high number of cross-links.

Morphology and Physicochemical Properties of Branched Polyurethane/Biopolymer Blends

The aim of this study is the analyze the structure of branched polyurethanes based on synthetic poly([R,S]-3-hydroxybutyrate) and their blends with biopolymers and montmorillonite. The properties which would predict the potential susceptibility of these materials to degradation are also estimated. Fourier-transform infrared spectroscopy with attenuated total reflection analysis shows that poly([d,l]-lactide) is on the surfaces of polyurethanes, whereas chitosan and starch are included inside the blend network. Atomic force microscopy images have shown that the surfaces of investigated samples are heterogenous with the formation of spherulites in case of pure polyurethanes. The presence of biopolymers in the blend reduced the crystallinity of polyurethanes. Thermal stability of blends of polyurethanes with poly([d,l]-lactide) and polysaccharides decreased in comparison to pure polyurethanes. Although the tensile strength is reduced after the blending of polyurethanes with biopolymers, the elongation at break increased, especially in the case of polyurethane/poly([d,l]-lactide) blends. The presence of polysaccharides in the obtained blends caused the significant reduction of contact angle after one minute from water drop immersion. This hydrophilizing effect is the highest when montmorillonite has been incorporated into the chitosan blend. The estimated properties of the obtained materials suggest their potential sensitivity on environmental conditions.

Beneficial effect of ovocystatin on the cognitive decline in APP/PS1 transgenic mice

PURPOSE

Cystatin C plays an important role in the course of neurodegenerative diseases and has a beneficial effect through inhibiting cysteine proteases and amyloid-β aggregation. It also induces proliferation and autophagy. Cystatin isolated from chicken egg white, called ovocystatin, has been widely used in the medical and pharmaceutical research due to its structural and biological similarities to human cystatin C. The aim of this study was to assess the effect of administering ovocystatin on the development of dementia-specific cognitive deficits in APP/PS1 transgenic mice.

MATERIALS/METHODS

The study was conducted on transgenic B6C3-Tg(APPswe,PSEN1dE9)85Dbo/Mmjax mice. Ovocystatin was administered to four-month-old transgenic (AD) and wild type (NCAR) mice in drinking water for 24 weeks (at a dose of 40 and 4 μg/ mouse). The locomotor activity and cognitive functions were determined using an actimeter and the Morris water maze test, respectively.

RESULTS

The results of the study indicate that ovocystatin has a beneficial effect on the cognitive functions in APP/PS1 transgenic mice. The strongest effects of ovocystatin were found in the group of AD mice, where ovocystatin was administered in drinking water at a dose of 40 μg/mouse (p < 0.05). Mice from the AD group swam statistically significantly further in the target zone during the trial in the Morris water maze compared to the AD (vehiculum) group (p < 0.05).

CONCLUSIONS

The obtained results encourage further research into the protective effect, which may be used as an adjuvant in the treatment of deteriorating cognitive functions.

Branched Polyurethanes Based on Synthetic Polyhydroxybutyrate with Tunable Structure and Properties

Branched, aliphatic polyurethanes (PURs) were synthesized and compared to linear analogues. The influence of polycaprolactonetriol and synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments on structure, thermal and sorptive properties of PURs was determined. Using FTIR and Raman spectroscopies it was found that increasing the R,S-PHB amount in the structure of branched PURs reduced a tendency of urethane groups to hydrogen bonding. Melting enthalpies (on DSC thermograms) of both soft and hard segments of linear PURs were higher than branched PURs, suggesting that linear PURs were more crystalline. Oil sorption by samples of linear and branched PURs, containing only polycaprolactone chains in soft segments, was higher than in the case of samples with R,S-PHB in their structure. Branched PUR without R,S-PHB absorbed the highest amount of oil. Introducing R,S-PHB into the PUR structure increased water sorption. Thus, by operating the number of branching and the amount of poly([R,S]-3-hydroxybutyrate) in soft segments thermal and sorptive properties of aliphatic PURs could be controlled.

Potential protective effect of ovocystatin on aging-related cognitive impairment in rats

Introduction: Increased occurrence of cognitive deficits in mild cognitive impairment is related with the phenomenon of aging within the population. Cystatin C has been associated with cysteine protease inhibiting properties as well as an induction of autophagy and proliferation that can potentially be used as an adjuvant in the treatment of cognitive decline. The aim of the study was to evaluate the effect of ovocystatin, which is structurally and biologically similar to cystatin C, on cognitive functions in experimental young and aging rat models. Material/Methods: The young (four-month-old) and aging (ten-month-old) Wistar Crl: Wi (Han) rats received ovocystatin (i.p.) for 12 days at a dose of 200 and 20 μg/rat, respectively. Cognitive functions were determined using the Morris water maze. Results: Ovocystatin treatment at a dose of 200 μg/rat improved the performance of old rats in the Morris water maze test via increasing the spent time and the distance traveled in the target zone but the differences were not statistically significant (p>0.05). The results of the study highlight the important role cystatins play in neurodegenerative processes as well as the influence they have on cognitive functions. Furthermore, the obtained findings suggest ovocystatin may be used in the treatment of mild cognitive impairment or cognitive decline in dementia, but further morphological, biochemical and immunohistochemical studies are needed.

Pharmacodynamic and pharmacokinetic interactions between simvastatin and diazepam in rats

BACKGROUND

Statins and benzodiazepines are widely used drugs, especially in ischemic heart disease, where exacerbation caused by anxiety can even lead to cardiac death. There have not been any reports of statin drug interaction with anxiolytics so far, but it is possible that these drugs interact with each other. We examined the effect of chronic oral administration of simvastatin on the anxiolytic activity and pharmacokinetics of diazepam in rats.

METHODS

Studies were conducted on male Wistar Han rats treated with simvastatin (2.5, 5, 10, 20mg/kg) for 4-6 weeks, and/or diazepam (2.5, 5, 10mg/kg) administered once on the day of the study. Evaluation of potential pharmacodynamic interaction was based on the behavioral tests: elevated plus maze (EPM) test and the Vogel conflict test (VCT). The assessment of the potential pharmacokinetic interaction was based on measurements of concentrations of diazepam and its metabolites in the blood of animals.

RESULTS

Diazepam 5 and 10mg/kg given together with simvastatin 10 and 20mg/kg showed no anxiolytic effect in the EPM test. In the VCT diazepam combinations with simvastatin did not produce any anxiolytic effect either, with an exception of the co-administration of diazepam 10mg/kg and simvastatin 10mg/kg. Simvastatin (20mg/kg) significantly reduced the area under curve (AUC) of diazepam by 51.6% and temazepam by 54.6%.

CONCLUSIONS

Abolition of diazepam anxiolytic effect during concomitant use of simvastatin is probably caused by diminished bioavailability of diazepam, although pharmacodynamic interaction between these drugs cannot be excluded.

The anxiolytic activity of n-3 PUFAs enriched egg yolk phospholipids in rat behavioral studies

Phospholipids play an important role in the biochemical and physiological processes of cells. An association between disturbed phospholipids metabolism in neuronal tissue and anxiety it was shown. The aim of this study was to examine the anxiolytic properties of phospholipids obtained from a new generation of eggs enriched in n-3 PUFA and its effect on locomotor activity in rat behavioral studies N-3 PUFA-enriched egg yolk phospholipids ("super lecithin") were added to the standard feed. Rats were fed by chow without (control group) or with (experimental group) addition of phospholipids. After six weeks of supplementation, the effect of phospholipids on locomotor activity in the open field test and anxiolytic properties in elevated plus maze and Vogel conflict test were examined. In the open field test the total distance traveled in the experimental group was similar to the control group. In the elevated plus maze test a six weeks phospholipids' administration significantly prolonged the time spent on the open arms by rats from experimental group compared to control group. The number of entries into the open arms was also increased but the difference was not statistically significant. The number of punished drinking water in the Vogel conflict test increased significantly in experimental versus control group. The obtained results suggest that the phospholipids isolated from n-3 PUFA enriched egg yolk have a specific anxiolytic effect, without general sedative influence.

Hierarchically structured ZSM-5 obtained by optimized mesotemplate-free method as active catalyst for methanol to DME conversion

In the presented studies, a new method for the synthesis of hierarchical porous materials with ZSM-5 zeolite properties was applied.

Fenofibrate subcellular distribution as a rationale for the intracranial delivery through biodegradable carrier

Fenofibrate, a well-known normolipidemic drug, has been shown to exert strong anticancer effects against tumors of neuroectodermal origin including glioblastoma. Although some pharmacokinetic studies were performed in the past, data are still needed about the detailed subcellular and tissue distribution of fenofibrate (FF) and its active metabolite, fenofibric acid (FA), especially in respect to the treatment of intracranial tumors. We used high performance liquid chromatography (HPLC) to elucidate the intracellular, tissue and body fluid distribution of FF and FA after oral administration of the drug to mice bearing intracranial glioblastoma. Following the treatment, FF was quickly cleaved to FA by blood esterases and FA was detected in the blood, urine, liver, kidney, spleen and lungs. We have also detected small amounts of FA in the brains of two out of six mice, but not in the brain tumor tissue. The lack of FF and FA in the intracranial tumors prompted us to develop a new method for intracranial delivery of FF. We have prepared and tested in vitro biodegradable poly-lactic-co-glycolic acid (PLGA) polymer wafers containing FF, which could ultimately be inserted into the brain cavity following resection of the brain tumor. HPLC-based analysis demonstrated a slow and constant diffusion of FF from the wafer, and the released FF abolished clonogenic growth of glioblastoma cells. On the intracellular level, FF and FA were both present in the cytosolic fraction. Surprisingly, we also detected FF, but not FA in the cell membrane fraction. Electron paramagnetic resonance spectroscopy applied to spin-labeled phospholipid model-membranes revealed broadening of lipid phase transitions and decrease of membrane polarity induced by fenofibrate. Our results indicate that the membrane-bound FF could contribute to its exceptional anticancer potential in comparison to other lipid-lowering drugs, and advocate for intracranial delivery of FF in the combined pharmacotherapy against glioblastoma.

Degradability in vitro of polyurethanes based on synthetic atactic poly[(R,S)-3-hydroxybutyrate]

The aim of the present study was to determine the degradability of aliphatic polyurethanes, based on a different amount of synthetic, atactic poly[(R,S)-3-hydroxybutyrate] (a-PHB), in hydrolytic (phosphate buffer) and oxidative (H2O2/CoCl2) solutions. The soft segments were built with atactic poly[(R,S)-3-hydroxybutyrate] and polycaprolactone or polyoxytetramethylenediols, whereas hard segments were the reaction product of 4,4'-methylenedicyclohexyl diisocyanate and 1,4-butanediol.The selected properties - density and morphology of polymer surfaces - which could influence the sensitivity of polymers to degradation processes - were analyzed.The analysis of molecular mass (GPC), thermal properties (DSC) and the sample weight changes were undertaken to estimate the degree of degradability of polymer samples after incubation in environments studied.Investigated polyurethanes were amorphous with the very low amount of crystalline phases of hard segments.The polyurethane synthesized with a poly[(R,S)-3-hydroxybutyrate] and polyoxytetramethylenediol at a molar ratio of NCO:OH=3.7:1 (prepolymer step) appeared as the most sensitive for both degradative solutions. Its weight and molecular mass losses were the highest in comparison to other investigated polyurethanes.It could be expected that playing with the amount of poly[(R,S)-3-hydroxybutyrate] in polyurethane synthesis the rate of polyurethane degradation after immersion in living body would be modeled.

Effects of supplementation with fish oil and n-3 PUFAs enriched egg yolk phospholipids on anhedonic-like response and body weight in the rat chronic mild stress model of depression

Polyunsaturated fatty acids play an important role in the human organism. They guarantee a normal function of nervous cells, influence neurotransmission, and build some elements of cellular membranes. Several reports indicate an association between a deficiency of polyunsaturated fatty acids and depression. The aim of this study was to examine the effects of diet supplemented with fish oil, which is rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs) and n-3 PUFAs enriched phospholipids ("super lecithin") obtained from designed eggs on anhedonic-like response and body weight in the rat chronic mild stress (CMS) model of depression. The results showed that neither fish oil nor n-3 PUFAs enriched egg yolk phospholipids supplementation reversed disturbances caused by CMS, such as anhedonic-like state or reduction of body weight gain.

Altered energy status of primary cerebellar granule neuronal cultures from rats exposed to lead in the pre- and neonatal period

This paper examines the effect of pre- and neonatal exposure of rats to lead (0.1% lead acetate in drinking water, resulting in rat offspring whole blood lead concentration (Pb-B) 4μg/dL) on the energy status of neuronal mitochondria by measuring changes in ATP, ADP, AMP, adenosine, TAN concentration, adenylate energy charge value (AEC) and mitochondrial membrane potential in primary cerebellar granule neurons (CGC) in dissociated cultures. Fluorescence studies were performed to imaging and evaluate mitochondria mass, mitochondrial membrane potential, intracellular and mitochondrial reactive oxygen species (ROS) production. The Na(+)/K(+) ATPase activity in intact CGC was measured spectrophotometrically. Our data shows that pre- and neonatal exposure of rats to Pb, even below the threshold of whole blood Pb value considered safe for people, affects the energy status of cultured primary cerebellar granule neurons through a decrease in ATP and TAN concentrations and AEC value, inhibition of Na(+)/K(+) ATPase, and increase in intracellular and mitochondrial ROS concentration. These observations suggest that even these low levels of Pb are likely to induce important alterations in neuronal function that could play a role in neurodegeneration.

The influence of ACEA--a selective cannabinoid CB1 receptor agonist on whole blood and platelet-poor plasma serotonin concentrations

Through the CB1 receptor cannabinoids modulate serotonin (5-hydroxytryptamine, 5-HT) release in the central nervous system which is connected with some of their pharmacological effects, especially antidepressant activity. 5-HT has many important physiological functions also in the periphery, particularly in the circulatory system and digestive tract. 5-HT dysfunction may be involved in some diseases pathogenesis including hypertension, migraine, cardiac disorders, cerebral ischemia or peripheral vascular diseases. Cannabinoids possible influence on 5-HT release in peripheral tissues may be clinically significant. The aim of the present study was to investigate the influence of ACEA (arachidonyl-2-chloroethylamide), a selective cannabinoid CB1 receptor agonist on whole blood (WB) and platelet-poor plasma (PPP) 5-HT levels. The experiments were carried out on male and female Wistar rats. ACEA (3 mg/kg i.p.) was given alone and in combination with a selective CB1 receptor antagonist AM 251 (3 mg/kg i.p.). Concentrations of 5-HT in WB and PPP were determined by enzyme-linked immunosorbent assay (Serotonin ELISA). ACEA significantly decreased concentration of 5-HT in WB (to 61%, p < 0.02) and its effect was blocked by AM 251. ACEA also reduced of 5-HT in PPP (to 62%) however, the difference was statistically insignificant. Research results reveal that due to CB1 receptor stimulation, ACEA reduces 5-HT contents in bloodstream. This effect is probably the result of inhibition of 5-HT release from gastrointestinal tract.

Involvement of nitric oxide in the gastroprotective effect of ACEA, a selective cannabinoid CB1 receptor agonist, on aspirin-induced gastric ulceration

The involvement of nitric oxide in the gastroprotective effect of ACEA (arachidonyl-2-chloroethylamide), a selective cannabinoid CB1 receptor agonist, on aspirin-induced gastric ulceration was studied in rats. ACEA (3 mg/kg i.p.) significantly reduced gastric ulcer formation. The gastroprotection of ACEA was attenuated by pretreatment with L-NAME (25 and 50 mg/kg i.p.), a nitric oxide synthase inhibitor. The combination of L-arginine (300 mg/kg i.v.), a precursor of nitric oxide with L-NAME (50 mg/kg i.p.) reversed the protective activity of ACEA (3 mg/kg i.p.). These results suggest that endogenous nitric oxide may be involved in the protective effect of ACEA.

Synthesis and anxiolytic activity of 1-phenyl-2-(4-aryl-1,3,4,5-tetrahydropyrido[2,3-b][1 ,4]diazepin-2-ylidene)-ethanone

A two-step, general synthesis of 1-phenyl-2-(4-aryl-1,3,4,5-tetrahydropyrido[2,3-b][1,4]diazepin-2-ylidene)-ethanones 3-9 is presented. This synthesis employs a condensation of 2,3-diaminopyridine with benzoylacetone followed by a basic-activated cyclization reaction with substituted benzaldehydes for final closure of the seven-membered ring. Molecular diversity is fixed by appropriate aldehydes: 2-chloro-, 4-chloro-, 2-bromo-, 4-bromo-, 4-fluoro-, 4-trifluoro- and 3-bromo-4,5-dimethoxybenzaldehyde. Compounds 4, 6, 8, 9 and 10 were examined for their anxiolytic activity. The most active was the compound with the chlorophenyl substituent i.e. 1-phenyl-2-{4-(4-chlorophenyl)-1,3,4,5-tetrahydropyrido[2,3-b][1,4]diazepin-2-ylidene}-ethanone (4).

ACEA (arachidonyl-2-chloroethylamide), the selective cannabinoid CB1 receptor agonist, protects against aspirin-induced gastric ulceration

The effect of a selective cannabinoid CB1 receptor agonist, ACEA (arachidonyl-2-chloroethylamide) in an aspirin-induced ulcer model was studied in rats. ACEA (1.25-5 mg/kg i.p.) significantly reduced gastric ulcer formation to 24, 21 and 0.6% respectively. These results confirm the cytoprotective effect of CB1 receptor agonists and suggest that the endocannabinoid system might be the target for a novel class of anti-ulcer drugs.

Effects of cannabinoids on the anxiety-like response in mice

Several pieces of anatomical, biochemical and pharmacological evidence indicate that the endocannabinoid system via CB1 receptors is implicated in the control of emotional behavior. However, previous studies have reported unclear and contradictory results concerning the role of cannabinoids in anxiety. The aim of the present study was to examine the influence of the cannabinoid agonist WIN 55,212-2 (1 and 5 mg/kg), the CB1 antagonist AM 281 (1, 2 and 4 mg/kg), the inhibitor of anandamide hydrolysis AACOCF3 (1 and 4 mg/kg) and the inhibitor of anandamide transporter AM404 (1 and 4 mg/kg) on the anxiety-like response in mice in the light/dark box test. WIN 55,212-2 (5 mg/kg) induced the anxiogenic-like effect accompanied by motor inhibition, AACOCF3 (4 mg/kg) induced the selective anxiolytic-like effect, whereas AM404 and AM281 were without effect. Pretreatment with AM281 (2 mg/kg) blocked the anxiogenic-like and sedative responses induced by WIN 55, 212-2, as well as the anxiolytic-like effect of AACOCF3. These results support the hypothesis that the endocannabinoid system is involved in the regulation of anxiety-like behavior, and also suggest that the inhibitors of anandamide hydrolysis might be potential anxiolytic drugs.

[Comparison of the early response to natural and synthetic surfactant in premature babies with respiratory distress syndrome]

OBJECTIVES

To compare the early response to natural and synthetic surfactant in premature babies with respiratory distress syndrome (RDS).

METHODS

This is a prospective study of 21 newborns with respiratory distress syndrome treated with natural or synthetic surfactant. The response rapidity after administration of natural or synthetic surfactant was compared by parameters of mechanical ventilation (FiO2, Pmax, IO) in the first 6 hours and during the following 7 days of life. The frequency of respiratory complications, presence of patent ductus arteriosus (PDA) and its treatment and causes of death were evaluated.

RESULTS

Definitely quicker decrease in ventilation parameters was observed after the administration of natural surfactant as compared to the synthetic one. Statistically significant differences were observed during 72 hours and then they decreased.

CONCLUSION

The response after the administration of natural surfactants in premature babies with RDS within the first six hours of treatment was significantly quicker than after synthetic surfactant. This improves the parameters of mechanical ventilation much quicker and prevents complications. Longitudinal studies of the development of children treated with both kinds of surfactant are necessary in order to evaluate the effects of the treatment in the neonatal period.

[Changes in the clinical picture of bronchopulmonary dysplasia]

The mortality of very preterm infants has significantly improved after introducing into clinical practice the antenatal use of glucocorticoid steroids prior to premature births and postnatal treatment with pulmonary surfactant which effectively decreases the tendency of the alveoli to collapse. The period of necessary mechanical ventilation was shortened. Reducing the concentration of inspired oxygen and inflation pressures became possible. In spite of this, long-term damage of lung tissue in immature infants is still a major clinical problem. However, its origin seems to be slightly different. A new form of bronchopulmonary dysplasia (BPD) has been recently evaluated. The most important factors in the pathogenesis of the "new" BPD are: lung tissue immaturity, infections initiating a cascade of events caused by formation of free oxygen radicals and cytokines and the presence of persistent patent ductus arteriosus. Primary prevention of BPD is possible by reducing the rates of prematurity and intrauterine infections. Secondary prevention includes antenatal steroids administration and postnatal surfactant treatment according to the accepted known standards. When protracted mechanical ventilation is necessary, low and subsequently reduced doses of i.v. glucocorticoid steroids in the second and third week of life are administrated, together with diuretics, bronchodilators and suitably high calorie feeding.

The effect of am 251, a cannabinoid CB1 receptor antagonist, on food intake in rats

The anorectic effect of AM 251 (N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-di-chlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide), a CB1 receptor antagonist, was studied in rats. AM 251 (0.5-2.0 mg/kg i.p.) significantly and dose-dependently reduced food intake in both free-feeding and food-deprived rats. The obtained results support the anorectic activity of CB1 receptors antagonists.

Antidepressant--like properties of ACEA (arachidonyl-2-chloroethylamide), the selective agonist of CB1 receptors

The antidepressant effect of ACEA (arachidonyl-2-chloroethylamide), a selective agonist of CB1 receptors, and its interaction with fluoxetine were studied in mice. ACEA (1.0 and 2.0 mg/kg i.p.) reduced the immobility time in the forced swimming test and attenuated the head - twitch response to L-5-HTP. The concomitant administration of ACEA (1.0 mg/kg i.p.) and fluoxetine (20 mg/kg i.p.) resulted in the strongest shortening of immobility time, significant in comparison with both ACEA and fluoxetine given alone. The obtained results indicate that ACEA may have antidepressant efficacy and shows a synergistic effect when given with fluoxetine in the forced swimming test.

Influence of nifedipine, nitrendipine and verapamil at low concentration on antipyrine metabolism examined by extracorporeal rat liver perfusion

An increase in calcium ion concentration in the cytoplasm due to the influence of various toxic agents causes disturbances in the structure and function of hepatocytes, leading to their damage and even death. Calcium ions enter the cell mostly through calcium channels, therefore, it has been suggested that calcium channel inhibitors (CCI) could protect hepatocytes from the action of toxic substances. The present study investigated the effect of the selected CCI (nifedipine, nitrendipine and verapamil) on liver function, measured by the efficiency of oxidation reaction, in this case by determination of the rate of antipyrine metabolism. The experiment was carried out using the method of extracorporeal liver perfusion (ELP). None of the studied CCI applied at a concentration of 50 micromol/l increased the rate of antipyrine metabolism over the whole period of ELP. However, supplementation of perfusion fluid with nifedipine, nitrendipine or verapamil at a concentration of 20 micromol/l considerably improved metabolic liver efficiency during the second hour of perfusion, i.e. at the time, when large number of hepatocytes started to perish, which could indicate protective action of the tested CCI. However, the CCI-induced acceleration of antipyrine metabolism was not a result of their influence on calcium channels, since these drugs block calcium channels, when given at the concentrations as high as 100-400 micromol/l. Moreover, it seems that facilitation of antipyrine metabolism during ELP was not due to their action on microsomal enzymes because CCI were administered at very low concentrations, besides, they are metabolic inhibitors, and not inducers. The present experiment suggests that low concentrations of CCI can exert hepatoprotective effect. However, confirmation of this conclusion requires further studies using other experimental methods.

The secretion of prostaglandin E2 and interleukin 1-beta in women with periodontal diseases and preterm low-birth-weight

Prematurity is of one of the main causes of neonatal morbidity and mortality. Clinical observations show, that periodontitis in pregnant women can be a direct risk factor for preterm labor, with a greater influence rate compared to other risk factors. The aim of the study was to asses the relationship between periodontal diseases and PLBW in the population of women from the Lower Silesian Region (Poland), and the evaluation of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta) levels in gingival cervicular (GCF) and blood serum in women with PLBW and women giving birth on time as well as secretion of these proinflammatory mediators in whole blood after bacterial lipopolysaccharide stimulation. The study group consisted of 84 women with PLBW (39.2% primiparous), aged 17-41 (mean 27.57). The controls were 44 women (47.7% primiparous) aged 16-38 (mean 26.36) who gave birth on time to a normal birthweight baby. PGE2 and IL-1 beta concentrations in serum and GCF were determined by means of immunoenzymatic method (EIA). In the studied population women over 28 years and exposed to medical risk factors had more frequent PLBW occurrence probability. In primiparous over 28 there is 4 times greater probability of preterm labor, and in case of the severe and generalized periodontitis presence there is 3.9 times higher possibility of PLBW compared to women with healthy periodontium. In all women with PLBW there is a significantly higher PGE2 and IL-1 beta concentration in GCF, and in primiparous also PGE2 level in blood serum, compared to controls.

Anorectic activity of 2H-4,6-dimethyl-2-[(4-phenylpiperazin-1- yl)methyl]-3-oxo-2,3-dihydroisothiazolo[5,4-b]pyridine

The effect of 2H-4,5-dimethyl-2-[(4-phenylpiperazin-1-yl)methyl]-3- oxo-2,3-dihydroisothiazolo[5,4-b]pyridine on feeding in rats was investigated. The tested compound decreased food intake in food-deprived rats and in rats receiving palatable-diet.