Interleukin-17 in acute myeloid leukemia

There are several reports that angiogenesis plays important roles in hematological malignancies including acute myeloid leukemia (AML). Human interleukin-17 (IL-17) is a proinflammatory cytokine produced by activated CD4 T cells. IL-17 plays a potential role in T cell mediated angiogenesis. The role of IL-17 in pathologic angiogenesis has not been evaluated yet. The aim of the study was to determine plasma level of IL-17 in patients with AML. IL-17 levels were measured by ELISA in plasma samples taken from 68 adult patients with AML before chemotherapy was administered. In addition 20 out of 68 patients were reanalysed after achieving complete remission (CR). Ten samples from healthy volunteers were evaluated as the control. In this study we have demonstrated that serum level of IL-17 is not elevated in AML patients. These results suggest that angiogenesis in AML is not mediated by CD4 T cells. To our knowledge this is the first report about IL-17 serum level in acute leukemias. We are currently evaluating IL-17 levels in others haematological malignancies.     

Expression of p16 in sporadic primary uveal melanoma

Expression of p16 protein, intragenic mutations of CDKN2A and hypermethylation of CDKN2A promoter region in 41 sporadic primary uveal melanomas were studied. There were 2 cases of spindle cell B histological type, 11 of A + B and 28 of mixed type. All melanomas infiltrated sclera but in 28 cases infiltration was superficial while in 13 profound. In 7 cases the tumor infiltrated the optic nerve. Expression of p16 was studied by immunohistochemistry and recorded by assessment of the proportion of positive tumor cells and staining intensity. Results were expressed as staining index (IRS). Intragenic mutations were studied by PCR-SSCP followed by sequencing, while hypermethylation of the promoter region by CpG methylation assay. In 15% of cases less than 10% of melanoma cells were p16 positive, in 70% of cases less than 50% of cells, while in 7% more than 80% of cells stained for p16 (mean IRS for all cases was 4.87 +/- 2.43). In B type the IRS was 8.5 +/- 0.7, in A + B type 6.0 +/- 2.1 and in the mixed type 4.17 +/- 2.43 (differences statistically significant). In melanomas profoundly infiltrating sclera mean IRS was 4.16, while in those infiltrating optic nerve 3.71 (statistically not significant). Analysis of the intragenic mutations revealed in two patients a GAC/GAT substitution in codon 84--a silent mutation. No hypermethylation of the CpG island of the p16 promoter region was found. In conclusion, we found that the degree of p16 expression is related to the histological type of tumor but not to the histological indicators of tumor invasiveness and that intragenic mutations and promoter hypermethylation are not major mechanisms of p16 inactivation in sporadic uveal melanoma.     

Affinity analysis of lectin interaction with immobilized C- and O- gylcosides studied by surface plasmon resonance assay

A biosensor based on the surface plasmon resonance (SPR) principle was used for kinetic analysis of lectin interactions with different immobilized saccharide structures. A novel affinity ligands beta-D-glycopyranosylmethylamines derived from common D-aldohexoses linked to the carboxymethyl dextran layer of the SPR sensor surface served for interactions with a wide range of lectins. The method of preparation and use of the beta-D-mannopyranosyl glycosylated sensor surface was described. The results of affinity analysis of lectin-ligand interactions were evaluated and compared with data obtained from measurements using commercially available p-aminophenyl alpha-D-glycopyranosides. Possible applications and advantages of C- and O-glycosylated SPR biosensors are discussed.     

The effect of catechol O-methylation on radical scavenging characteristics of quercetin and luteolin--a mechanistic insight

The biological effect of flavonoids can be modulated in  vivo due to metabolism. The O-methylation of the catechol group in the molecule by catechol O-methyl transferase is one of the important metabolic pathways of flavonoids. In the present study, the consequences of catechol O-methylation for the pH-dependent radical scavenging properties of quercetin and luteolin were characterized both experimentally and theoretically. Comparison of the pKa values to the pH-dependent TEAC profiles reveals that O-methylation not only affects the TEAC as such but also modulates the effect of changing pH on this radical scavenging activity due to an effect on the pKa for deprotonation. The pH-dependent TEAC curves and computer calculated electronic parameters: bond dissociation energy (BDE) and ionisation potential (IP) even indicate that O-methylation of the luteolin catechol group affects the radical scavenging potential only because it shifts the pKa for deprotonation. O-Methylation of the quercetin catechol moiety affects radical scavenging capacity by both an effect on the pKa, and also by an effect on the electron and hydrogen atom donating properties of the neutral (N) and the anionic (A) form of the molecule. Moreover, O-methylation of a catechol OH-group in quercetin and luteolin has a similar effect on their TEAC profiles and on calculated parameters as replacement of the OH-group by a hydrogen atom. Altogether, the results presented provide new mechanistic insight in the effect of catechol O-methylation on the radical scavenging characteristics of quercetin and luteolin.     

Molecular mechanisms of neuroprotective action of immunosuppressants--facts and hypotheses

Cyclosporin A (CsA) and FK506 (Tacrolimus) are short polypeptides which block the activation of lymphocytes and other immune system cells. Immunosuppressants exert neuroprotective and neurotrophic action in traumatic brain injury, sciatic nerve injury, focal and global ischemia in animals. Their neuroprotective actions are not understood and many hypotheses have been formed to explain such effects. We discuss a role of drug target - calcineurin in neuroprotective action of immunosuppressants. Protein dephosphorylation by calcineurin plays an important role in neuronal signal transduction due to its ability to regulate the activity of ion channels, glutamate release, and synaptic plasticity. In vitro FK506 protects cortex neurons from NMDA-induced death, augments NOS phosphorylation inhibiting its activity and NO synthesis. However, in vivo experiments demonstrated that FK506 in neuroprotective doses did not block excitotoxic cell death nor did it alter NO production during ischemia/reperfusion. Tissue damage in ischemia is the result of a complex pathophysiological cascade, which comprises a variety of distinct pathological events. Resident non-neuronal brain cells respond rapidly to neuronal cell death and may have both deleterious and useful role in neuronal damage. There is increasing evidence that reactive gliosis and post-ischemic inflammation involving microglia contribute to ischemic damage. We have demonstrated that FK506 modulates hypertrophic/proliferative responses and proinflammatory cytokine expression in astrocytes and microglia in vitro and in focal transient brain ischemia. Our findings suggest that astrocytes and microglia are direct targets of FK506 and modulation of glial response and inflammation is a possible mechanism of FK506-mediated neuroprotection in ischemia.     

Out-of-laboratory control screening of growth mediums used by sanitary service laboratories for isolation of pathogenic enteric bacteria from fecal specimens

The aim of the study was to test the selective-differential plating mediums used for isolation of Salmonella and Shigella for routine stool specimens examination for epidemiological and sanitary purpose. Three plates of any such medium used in the laboratories in 37 Sanitary Service Stations in Poland were obtained. The specimens of Mac Conkey Lactose Bile Salt Agar and SS Agar were obtained from all laboratories, Hektoen Enteric medium from 8 and EosinMethylene Blue Agar from only one laboratory. The desiccated substrates of these mediums originated from 11 manufactures. The mediums were inoculated by "drops" method. The five control strains of selected taxons were chosen from National Institute of Hygiene strains collection. The quality of growth was evaluated by comparison with the growth on two control mediums: the general outlook of bacterial colonies, size and number of cfu/ml was taken under consideration. It was found that the results were satisfying for Hektoen medium, Levine and all but two Mac Conkey's medium specimens. The results of growth on SS medium were much worse: only on 10 specimens out of 39 checked supported properly the growth of all the five control strains. On 18 specimens the growth appeared after 48 hours of incubation and the size of colonies was too small to be isolated. On 11 there was no growth on 1, 2 or 3 control strains. The need of systematic extra-laboratory control of plating mediums used for examination stool specimen was shown.     

Haemonchus contortus: characterization of the baculovirus expressed form of aminopeptidase H11

Recombinant form of Haemonchus contortus aminopeptidase H11, an intestinal membrane glycoprotein considered to be in its native form the most promising vaccine candidate, was produced in insect cells, characterised and tested in pilot vaccination-challenge trial on sheep. The sequence of the cloned gene, obtained by RT PCR isolated from adult worms, showed 97% identity to the highly immunogenic H11 clone, described by Graham et al., (database accession number AJ249941.1). A 1305 bp fragment of H11 was expressed in E. coli and used to raise a specific antiserum, which recognized recombinant forms of H11 and 110 kDa protein from H. contortus extract. H11 was expressed by baculovirus recombinants in insect cells in full length and as a fusion protein with H. contortus glutathione S-transferase (GST). The baculovirus produced recombinant antigens were used without adjuvants to immunize sheep, which resulted in 30% (full length H11) and 20% (GST-H11) reduction of worm burden. These animal experiments indicated that, although the protection induced by in vitro produced protein is lower than in case of H11 isolated from worms, recombinant forms of aminopeptidase may be considered as antigens for the control of haemonchosis.