Ladislava Bartošová

Diplacone and mimulone ameliorate dextran sulfate sodium-induced colitis in rats

Diplacone (1) and mimulone (2), two geranylated flavanones, have previously shown anti-inflammatory and antiradical activity in vitro. The present study aimed to evaluate their activity in vivo on a model of colitis induced in Wistar rats by an oral administration of dextran sulfate sodium (DSS). Diplacone (1) and mimulone (2) were administered at a bolus dose of 25mg/kg by gastric gavage 48 and 24h prior to the induction of colitis by DSS and every 24h on the following days of the experiment. The effect of the treatment was assessed by monitoring the disease activity index (DAI), histopathological examination, evaluation of the weight and length of the colon and by analysis of the levels and activities of cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP2), superoxide dismutase-2 (SOD2), and catalase (CAT) in the inflamed tissue. Administration of the test compounds prior and after induction of colitis ameliorated the symptoms of colitis (diarrhea, presence of the blood in the stool) and delayed their onset. The ability of compounds 1 and 2 to reduce the levels of COX-2 and to increase the ratio of pro-MMP2/MMP2 activity correlates with the values of the DAI. The lowering of the levels of the antioxidant enzymes SOD2 and CAT reflects the ability of the test compounds to scavenge reactive oxygen species.

Antibacterial efficiency of vermiculite/chlorhexidine nanocomposites and results of the in vivo test of harmlessness of vermiculite

Clay minerals have been proposed as very useful materials for modulating drug delivery. These are the commonly used materials in pharmaceutical production both as inorganic carriers or active agents. We focused on the development of suitable long-acting material for local treatment of oral infection where clay minerals act as inorganic drug carriers. Organovermiculites with antibacterial activity were prepared by ion exchange reactions using different concentrations of chlorhexidine diacetate. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TGA). The antibacterial activity was evaluated by finding the minimum inhibitory concentration (MIC). All studied organoclays possessed good antibacterial activity after 24h exposure against Escherichia coli, Enterococcus faecalis and particularly against Staphylococcus aureus. Pseudomonas aeruginosa however proved very resistant as only the sample with the highest concentration of CA that successfully inhibited bacterial growth. Furthermore, clay mineral vermiculite was subjected to in vivo toxicological analysis and its influence on gastrointestinal tract during its oral application was investigated. Tissue samples from buccal mucosa, tongue, esophagus, stomach, terminal duodenum, small intestine, caecum, distal colon and liver were subjected to histological examination, both macroscopically and microscopically. Neither systemic nor local reactions were observed. Therefore the toxicity of vermiculite to a mammal model organism can be excluded.

Polymorphism G-308A in the promoter of the tumor necrosis factor-α gene and its association with the risk of venous thromboembolism.

The main abnormalities associated with the increased risk of venous thrombosis are the inherited deficiencies of antithrombin, protein C, protein S, the point mutations known as factor V Leiden and factor II G20210A. The association of other specific genes with thrombotic risk is less known. G–308A polymorphism in the promoter area of the gene coding for tumor necrosis factor &agr; (TNF-&agr;) is associated with an increased transcription activity of this gene, increased TNF-&agr; production and subsequent predisposition to some illnesses. The aim of this work was to study the link between this polymorphism and predisposition to deep venous thrombosis (DVT). The research determined the frequency of the variant allele −308A in the gene for TNF-&agr; in a group of 67 patients diagnosed with DVT and in a group of 62 healthy volunteers. We confirmed statistically significant link between the occurrence of the variant allele −308A and DVT (P = 0.02). This mutation was associated with a 2.64-fold greater risk of venous thrombosis, 95% confidence interval (1.19–5.87). When excluding heterozygous and homozygous carriers of the Leiden mutation from both groups, the difference between the occurrence of the variant allele −308A in the groups of ill and healthy individuals remained statistically significant (P = 0.04). The statistical significance was also confirmed after the exclusion of patients with mutation in the gene for prothrombin (P = 0.02). The results of this work imply possible association between the variant allele −308A and the development of DVT.

Successful Mercaptopurine Usage Despite Azathioprine-Induced Pancreatitis in Paediatric Crohn's Disease

BACKGROUND Azathioprine [AZA] and mercaptopurine [MP] are recommended for maintenance of steroid-free remission in children with Crohn`s disease [CD]. Azathioprine-induced pancreatitis, an idiosyncratic and major side effect, has been considered as an absolute contraindication for the use of a second thiopurine in IBD patients. MATERIALS AND METHODS We describe two children with CD in whom MP were successfully trialled after a confirmed azathioprine-induced pancreatitis, being well tolerated in both cases. RESULTS Two boys [13 and 10 years old] started exclusive enteral nutrition after diagnosis of moderate (Pediatric Crohns Disease Activity Index [wPCDAI] = 45) and mild [wPCDAI = 35] CD. Both developed an acute mild to moderate pancreatitis after 2 and 3 weeks, respectively, of AZA treatment but recovered fully in hospital after AZA withdrawal. They started on MP treatment without any adverse effect. They were tested for the presence of polymorphisms 238G>C, 460G>A, and 719A>G in the TPMT gene and 94C>A and 21>C in the ITPase. Both patients were wild-type for all tested polymorphisms. CONCLUSIONS Azathioprine-induced acute pancreatitis should not be considered as an absolute contraindication for the use of MP. Further investigation is required to create a better understanding of the mechanism underlying the adverse events and to allow more possibilities for personalised therapy.

Local tissue reaction after the application of topical hemostatic agents in a rat partial nephrectomy model.

Various hemostatics are used for renal surgical procedures. We investigated the hemostatic efficacy of cellulose derivatives on the model of partial nephrectomy in rats focusing on the local reaction of renal parenchyma. A total of 50 Wistar rats were divided into five groups of 10 animals each. Partial nephrectomy of the caudal pole without hilar vascular control was performed. Oxidized cellulose (OC), sodium salt of oxycellulose (OCN), carboxymethyl cellulose (CMC), dialdehyde cellulose (DAC), and gelatin-based hemostatic (C) were applied to the bleeding wounds. The time to hemostasis was monitored. Half of the animals were euthanized after 3 days, the second half 30 days from the experiment start date. The left kidney was excised and subjected to histopathological examination. The biochemical data was subjected to statistical analysis. The time to hemostasis in all groups was significantly less than in the C group (in OC p = 0.0057, OCN p = 0.0039, CMC and DAC p = 0.0001). In the C group, massive hemorrhages and necrosis did occur. In the OC and OCN groups, there were regenerative changes, a receding inflammatory reaction and hemorrhage. DAC caused an immune reaction and massive interstitial hemorrhages with biochemical signs of liver damage. Parenchyma in CMC revealed a reduction of necrosis and interstitial hemorrhages with regenerative processes. The most effective hemostatics were CMC and OC, achieving the best results both in the time to hemostasis, and for histopathological evaluation.

Three polymorphisms in promoter of protein C gene with endothelial protein c receptor gene and risk of venous thrombosis.

The primary abnormalities that are associated with a risk of venous thrombosis are the deficiencies of protein C. Protein C (PROC), encoded by the PROC gene, acts through its affinity for binding to its transmembrane endothelial cell protein C receptor (EPCR) encoded by the EPCR gene. The objective of the study was to analyze the link between three polymorphisms in the promoter of PROC gene, the polymorphism in the EPCR gene and the occurrence of venous thrombosis. We genotyped 135 individuals – 51 cases with documented venous thrombosis and 84 healthy volunteers without a history of venous thrombosis. The occurrence of the TAA haplotype of PROC gene was significantly more frequent in the controls (N = 48; 57.1%), compared with the patients (N = 18; 35.3%), (P = 0.0206). The healthy individuals were also significantly often carriers of the TAA haplotype and the standard genotype AA of EPCR gene (50 vs. 25.5%) than the patients (P = 0.0066). The frequency of haplotypes CAA and CGT of PROC gene was insignificantly higher in the patients (15.7 and 21.6%, respectively) than in the control group (9.5 and 13.1%). The combination of haplotype CAA/CAA of PROC gene and variant genotype AG of EPCR gene was confirmed with a higher frequency in the group of patients (3.9 vs. 1.2%).This analysis showed that the PROC haplotype associated with a high protein C level (TAA) and the EPCR AA genotype was significantly more frequent in the healthy volunteers (P = 0.0066). Haplotypes associated with a low production of protein C (CAA or CGT) were more frequent in patients with venous thrombosis.

Cardioprotective effects of 44Bu, a newly synthesized compound, in rat heart subjected to ischemia/reperfusion injury.

Excessive intracellular Na+ accumulation followed by Ca2+ overload in cardiac tissue is one of the important mechanisms leading to ischemia/reperfusion injury. In the present study, the cardioprotective effects of 44Bu, 2-hydroxy-3-(butylamino) propyl-4-{(butoxycarbonyl)amino}benzoate hydrochloride, a novel Na+ channel blocker, on ischemia/reperfusion injury were investigated and compared to lidocaine. Isolated rat hearts perfused at the constant flow were exposed to global ischemia for 60 min followed by 30 min of reperfusion. In control hearts, ischemia/reperfusion markedly decreased left ventricular developed pressure and increased left ventricular end-diastolic pressure, and caused lactate dehydrogenase release and infarction. 44Bu (0.1, 0.3 and 1 microM) or lidocaine (1 and 200 microM) was administrated during the last 10 min before ischemia and the first 5 min of the reperfusion period. A significant post-ischemic functional recovery in the same degree was elicited by 0.3 and 1 microM 44Bu or 200 microM lidocaine. These effects of 44Bu and lidocaine closely correlated with the reduction in the infarct size and lactate dehydrogenase release. In contrast, 44Bu (0.1 microM) or lidocaine (1 microM) treatment did not result in a significant recovery in any of the examined parameters. In accordance with functional results, our electrophysiological data demonstrated that 44Bu was a more potent agent than lidocaine in terms of transient Na+ current inhibition. On the other hand, 44Bu did not cause any change in Ca2+ currents and on Na+/H+ exchange activity. These results show that 44Bu, as a novel Na+ channel blocker, has cardioprotective effects against ischemia/reperfusion injury.