Importance of interleukin 6 in pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), is an uncontrolled chronic inflammation of the gastrointestinal tract caused by an interaction of diverse genes and environmental factors. There is growing evidence that cytokine production plays an important role in IBD. One of the key roles in signaling pathway in development of IBD is performed by interleukin 6 (IL-6), although molecular mechanism of this pathway is not yet fully understood. In order to assess the clinical relevance of IL-6 serum concentration in patients with CD and UC we performed cross-sectional, case-control study of IL-6 levels in patients' and healthy blood donors' sera. A total of 100 CD and UC patients and 71 healthy blood donors were investigated. Clinical activity of CD and UC was evaluated using the Crohn's disease activity index and Truelove-Witt's criteria, respectively. Quantitative assessment of serum IL-6 was performed with solid-phase, enzyme-labeled, chemiluminescent sequential immunometric assay. Our results indicate that serum IL-6 is a clinically relevant parameter for CD and UC that strongly correlates with inflammatory activity of disease. We confirmed and extended the role of cytokine production patterns for IBD presentation in Croatian population.

Pilot study of variants of the IL-23R and STAT3 genes reveals no association with Hashimoto's thyroiditis in the Croatian population

Interleukin-23 receptor (IL-23R) and signal transducer and activator of transcription 3 (STAT3) polymorphisms are common risk factors for a number of T helper (Th) 17-mediated autoimmune diseases. However, the importance of genetic variations in Th17 pathways to thyroid autoimmunity, and particularly Hashimoto's thyroiditis (HT), is not fully understood. In this study, we genotyped three single nucleotide polymorphisms (SNPs) within the IL-23R (rs11209026/p.Arg381Gln, rs7530511) and STAT3 (rs744166) genes in 217 Croatian patients with HT and 161 healthy controls using fluorescence resonance energy transfer technology and melting curve analysis of polymerase chain reaction products. None of the tested SNPs or IL-23R haplotypes was associated with HT susceptibility or disease severity. These results suggest that the studied IL-23R/STAT3 polymorphisms affecting Th17 signaling efficiency are not major determinants of HT risk in the Croatian population. Further work is necessary to determine if these loci contribute modestly or conditionally to the risk of HT.

Polymorphisms of interleukin-23 receptor in patients with inflammatory bowel disease in a Croatian tertiary center

The Interleukin-23 signalling pathway is important for the differentiation of TH17 lymphocytes and is involved in the pathogenesis of Inflammatory bowel disease. Polymorphisms in the IL-23 receptor gene were previously found to be associated with Inflammatory bowel disease in various populations. The aim of this study was to determine whether the specific rs11209026 and rs7530511 single-nucleotide polymorphisms in the Interleukin-23 receptor gene are associated with Crohn's disease and ulcerative colitis in a Croatian patient population. A total of 50 patients with Crohn's disease and 93 patients with ulcerative colitis, as well as 99 healthy control subjects were included in the study. The results determined a significantly higher occurrence of rs11209026 in control group compared to patients with inflammatory bowel disease, suggesting a protective effect of this polymorphism. The rs11209026 variant was strongly associated with Crohn's disease, but it was absent in ulcerative colitis. However, there was no significant association between the rs7530511 polymorphism with either ulcerative colitis or Crohn's disease. Associations presented in this study give potentially important insight into the roles of specific Interleukin-23 receptor polymorphisms in Crohn's disease pathogenesis in the Croatian population.

PAX8-PPARgamma oncogene in follicular thyroid tumors: RT-PCR and immunohistochemical analyses

US-guided fine needle aspiration cytology is currently the best diagnostic tool for thyroid nodules. However, it is not sensitive and specific enough for differentiating between benign and malignant follicular tumors. A potentially useful marker for this differentiation is the PAX8-PPARgamma rearrangement, identified in follicular thyroid carcinomas, but not in follicular adenomas or other types of thyroid tumors. The aim of this research was to determine the clinical significance of the PAX8-PPARgamma oncogene in diagnostics follicular thyroid tumors. The study included 62 patients with follicular or Hürthle cell tumors. Gene expression was determined by reverse transcription-polymerase chain reaction (RT-PCR) from paraffin embedded tissues, and PCR products were checked using the agarose gel electrophoresis. The immunohistochemical analysis was performed on archive paraffin embedded tissues with the monoclonal PPARgamma antibody. The statistical analysis has indicated that neither the expression of PAX8-PPARgamma mRNA, nor the immunohystochemical analysis with the PPARgamma antibody correlate with the patohystological diagnosis. The oncogene, PAX8-PPARgamma has not met the expectations as a reliable tumor marker for differentiation between benign and malignant thyroid tumors, which makes the only reliable histological criteria--capsular and vascular invasion.

Polymorphisms of vitamin D receptor gene in the population of eastern Croatia with psoriasis vulgaris and diabetes mellitus

The aim of this study was to evaluate the possible association between polymorphisms in the Vitamin D receptor gene (VDR gene) and tendency for development of psoriasis vulgaris and diabetes mellitus in the population of Slavonia, which is a region in the Eastern Croatia. In order to conduct the mentioned evaluation the restriction fragment length polymorphisms (ApaI, BsmI and TaqI) in the Vitamin D receptor gene were researched in three groups of patients: patients suffering only from psoriasis vulgaris, patients suffering only from diabetes mellitus, and patients suffering at the same time from both diseases. Four most common genotypes were found in all standardized control patients: triple heterozygotes BbAaTt (in 29.3% of the studied patients), bbAaTT (in 18.6% of the studied patients), bbaaTT (in 12.9% of the studied patients) and BbAATt (in 8.6% of the studied patients). Three most common VDR 3'-RFLP haplotypes determined in this study were: three-component baT, Bat and bAT haplotype. Results of the Hardy-Weinberg equilibrium showed presence of BsmI polymorphism genotype frequencies disequilibrium in the group of patients suffering from psoriasis and ApaI polymorphism in the group of patients suffering from both diseases. According to the same statistical test all conditions for TaqI polymorphism genotype frequency were fulfilled in all groups of studied patients. There was no significant difference in distribution of BsmI, ApaI or TaqI polymorphism genotype frequencies between control patients and any of the subgroup of studied patients. In studied population none of analysed polymorphisms individually was associated with the risk of development of psoriasis, diabetes or combined phenotype.

Hh-Gli signaling pathway activity in oral and oropharyngeal squamous cell carcinoma

BACKGROUND

The aim of this study was to examine the role of Hh-Gli signaling in oral and oropharyngeal squamous cell carcinoma (SCC). The role of this signaling pathway in SCC formation has not yet been elucidated.

METHODS

Sixty-four tissue and blood samples were collected from 60 patients with SCC, all tobacco and alcohol users. An additional six buccal mucosa tissue samples were collected from nonsmokers and nondrinkers as control tissue.

RESULTS

Hedgehog-Gli pathway components were associated with clinical and pathologic features. Broders' grade and N stage were associated with higher Ptch1 and lower Gli1 expression. Tumor stage was negatively associated with Smo expression, and tumor size was positively associated with p16 expression. Ptch1 and Shh were frequently detected in the surrounding stroma. Ptch1 was found to be correlated with p16 expression, as well as with survivin expression.

CONCLUSIONS

The signaling pathway is activated in SCC and inducible in vitro by Shh protein.

Insulin administration in the mild hyperglycaemia changes expression of proinflammatory adhesion molecules on human aortic endothelial cells

An overexpression of cell adhesion molecules (CAMs) on the surface of endothelial cells is one of the first steps in a high glucose-mediated endothelial dysfunction in diabetic patients. The effect of insulin administration in the condition of elevated glucose concentration on the E-selectin, intracellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) expression on human aortic endothelial cells (HAEC) was investigated. Cells were cultured for 4 h in a medium supplemented with homocysteine (7 pM) and different concentration of glucose (5.5, 8.0, 12.0 and 16.5 mM respectively) with or without insulin (1 mlU/mL) addition. Expression of CAMs was analysed by flow-cytometry using monoclonal antibodies. Controls were CAMs expression in the medium with a corresponding glucose concentration. Obtained results show that short-term exposure of HAECs to moderate high glucose concentrations results in increased expression of E-selectin (2-fold), VCAM-1 (3-fold) and ICAM-1 (47%). At the same time, HAEC grown with 12 mM glucose expressed lesser E-selectin and, more ICAM-1 (for 64%) and VCAM-1 (41%) molecules. 16.5 mM glucose decreased expression of all investigated adhesion molecules. Addition of insulin was not changed expression of CAMs in a medium with 5.5 mM glucose. In conditions of elevated glucose concentration (12 mM), addition of insulin significantly dropped E-selectin (27%) and increased VCAM-1 (23%) expression. In conclusion, moderate elevated glucose concentration increased expression of cell adhesion molecules on HAEC. Insulin administration in the mild hyperglycaemia reduces an expression of the proinflammatory adhesion molecule E-selectin which could contribute in deceleration of macrovascular complications development in diabetic patients.

9-Deazaguanine derivatives connected by a linker to difluoromethylene phosphonic acid are slow-binding picomolar inhibitors of trimeric purine nucleoside phosphorylase

Genetic deficiency of purine nucleoside phosphorylase (PNP; EC 2.4.2.1) activity leads to a severe selective disorder of T-cell function. Therefore, potent inhibitors of mammalian PNP are expected to act as selective immunosuppressive agents against, for example, T-cell cancers and some autoimmune diseases. 9-(5',5'-difluoro-5'-phosphonopentyl)-9-deazaguanine (DFPP-DG) was found to be a slow- and tight-binding inhibitor of mammalian PNP. The inhibition constant at equilibrium (1 mm phosphate concentration) with calf spleen PNP was shown to be = 85 +/- 13 pm (pH 7.0, 25 degrees C), whereas the apparent inhibition constant determined by classical methods was two orders of magnitude higher ( = 4.4 +/- 0.6 nm). The rate constant for formation of the enzyme/inhibitor reversible complex is (8.4 +/- 0.5) x 10(5) m(-1).s(-1), which is a value that is too low to be diffusion-controlled. The picomolar binding of DFPP-DG was confirmed by fluorimetric titration, which led to a dissociation constant of 254 pm (68% confidence interval is 147-389 pm). Stopped-flow experiments, together with the above data, are most consistent with a two-step binding mechanism: E + I <--> (EI) <--> (EI)*. The rate constants for reversible enzyme/inhibitor complex formation (EI), and for the conformational change (EI) <--> (EI)*, are k(on1) = (17.46 +/- 0.05) x 10(5) m(-1).s(-1), k(off1) = (0.021 +/- 0.003) s(-1), k(on2) = (1.22 +/- 0.08) s(-1) and k(off2) = (0.024 +/- 0.005) s(-1), respectively. This leads to inhibition constants for the first (EI) and second (EI)* complexes of K(i) = 12.1 nM (68% confidence interval is 8.7-15.5 nm) and = 237 pm (68% confidence interval is 123-401 pm), respectively. At a concentration of 10(-4) m, DFPP-DG exhibits weak, but statistically significant, inhibition of the growth of cell lines sensible to inhibition of PNP activity, such as human adult T-cell leukaemia and lymphoma (Jurkat, HuT78 and CCRF-CEM). Similar inhibitory activities of the tested compound were noted on the growth of lymphocytes collected from patients with Hashimoto's thyroiditis and Graves' disease. The observed weak cytotoxicity may be a result of poor membrane permeability.

Antiproliferative activity of purine nucleoside phosphorylase multisubstrate analogue inhibitors containing difluoromethylene phosphonic acid against leukaemia and lymphoma cells

Potent inhibitors of purine nucleoside phosphorylase (PNP) are expected to act as selective agents against T-cell tumours. Five compounds with guanine, three with hypoxanthine, and five with 9-deazaguanine, all connected by a linker with difluoromethylene phosphonic acid, were studied on their inhibitory potential against human and calf PNPs. Antiproliferative activity of these analogues against lymphocytes as well as lymphoma and leukaemia cells has been also investigated. All tested compounds act as multisubstrate analogue inhibitors of PNP with the apparent inhibition constants in the range 5-100 nm, and also show a slight antiproliferative activity. Analogues with 9-deazaguanine aglycone have better anti-leukaemic and anti-lymphoma activities compared to the guanine and hypoxanthine analogues, and applied in the concentration of 100 mum, caused a statistically significant decrease in the cell viability in all human leukaemia and lymphoma cells used. Despite the high PNP inhibitory potential of tested analogues, no differences were observed between the effects on the growth of tumour cells sensible to the inhibition of PNP, such as human adult T-cell leukaemia and lymphoma cells, and other investigated cells. Obtained poor effects on cell proliferation could be explained probably by a poor ability of tested compounds to penetrate cell membranes.

An overview of coagulation disorders in cancer patients

A diversity of coagulation disorders in cancer patients arise from tumor-specific growth characteristics, neoangiogenesis with impaired endothelial lining, defective myelopoiesis, hypoproteinemia or metastatic lesions growth with organ dysfunction. Recent investigations have found a clinically relevant correlation of coagulation disorders and tumor growth. These prompted new therapeutic strategies focused on growth factors with the aim to control tumor metastasis, particularly if used for the treatment of micrometastatic disease. However, such treatment may lead to the life threatening coagulation imbalance. A coagulation homeostasis may become further impaired after nonsurgical cancer therapy, especially after preoperative irradiation, which produces lesions precipitating both bleeding and thrombosis. Anticancer chemotherapy may affect liver function and decrease the synthesis of both procoagulation and anticoagulation factors. The most of chemotherapeutic protocols affect platelet synthesis, which arises as a principal dose-limiting side effect. It was observed both during combined systemic chemotherapy and local antitumor therapy. Although the side effects produced by chemotherapy are reversible, endothelial lesions may persist for many years after the anticancer treatment. Instead of cancer patients, there's a growing cohort of patients with nonmalignant diseases who use cytostatics in the perioperative period, and are candidates for surgical procedures not related to their malignant disease, i.e. hernia repair. In this patient population a special attention must be paid to the preoperative evaluation of coagulation status and thromboprophylaxis. This overview reminds the most common coagulation disorders in cancer patients in the perioperative period. It emphasizes the need for proper patient monitoring which may facilitate the diagnostics and treatment of cancer-related coagulation disorders in the perioperative setting.

Vitamin D endocrine system and psoriasis vulgaris--review of the literature

Vitamin D exerts its physiological functions on calcium and bone metabolism in humans through the active metabolite 1,25-dihydroxyvitamin D3(1,25(OH)2D3). The other spectrum of vitamin D activities includes important effects on cellular proliferation, differentiation and the immune system. These effects are mediated through the intracellularly located vitamin D receptor (VDR). VDR is a member of the steroid, estrogen and retinoid receptor gene family of proteins that mediate transcriptional activities of the respective ligands. The VDR complex binds in the nucleus to the vitamin D responsive element on the gene. Several polymorphisms of the vitamin D receptor (VDR) gene have been described including FokI in exon 2, BsmI and ApaI in intron 8 and TaqI in exon 9. Alterations in vitamin D-1,25 (OH)2D3 levels and polymorphisms of VDR gene have been shown to be associated with several malignant or autoimmune diseases such as sclerosis multiplex, breast cancer, diabetes mellitus, malignant melanoma, and psoriasis vulgaris. The effects of VDR gene polymorphisms including immunomodulation, stimulation of cellular differentiation and inhibition of proliferation make it a possible candidate for therapy of psoriasis as well as for the psoriasis gene modification. The objective of this article is to present the state-of-the-art in the VDR gene polymorphism research in psoriasis vulgaris.

Inhibitory properties of nucleotides with difluoromethylenephosphonic acid as a phosphate mimic versus calf spleen purine nucleoside phosphorylase and effect of these analogues on the viability of human blood lymphocytes

Several cyclic and acyclic 6-keto purine nucleotides with difluoromethylenephosphonic acid as phosphate mimic are proved to be potent inhibitors of mammalian purine nucleoside phosphorylase (PNP). Antiproliferative activity of these analogues on the growth of human blood lymphocytes was tested by MTT assay. Compared to inhibitory effects on the growth of human blood T-lymphocytes isolated from healthy donors, all analogues significantly slow down proliferation of T-lymphocytes isolated from patients with autoimmune thyroid disease--Hashimoto's thyroiditis.

Association of vitamin D receptor gene 3'-variants with Hashimoto's thyroiditis in the Croatian population

Hashimoto's thyroiditis (HT) is the most frequent autoimmune thyroid disease with strong genetic background. Vitamin D receptor (VDR) endocrine system affects immunosuppressive, regulatory and tolerogenic decisions required for induction and maintenance of peripheral immune tolerance. With respect to the biological function of the VDR and functionally plausible gene-expression data, we sought to test whether particular 3'-restriction fragment length polymorphisms (RFLP) and haplotypes previously directly or indirectly associated with VDR mRNA 3'-allelic imbalance phenotype and differences in total VDR mRNA expression are implicated in HT susceptibility. Thus, 145 Croatian HT patients and 145 age-, sex- and ethnically matched euthyroid controls were genotyped for VDR rs1544410 (BsmI), rs7975232 (ApaI) and rs731236 (TaqI) polymorphisms by polymerase chain reaction-RFLP method. Covariate-adjusted single-locus and haplotype-phenotype regression analyses were performed. Permutation corrections (P(c)) and Akaike Information Criteria were used for model comparisons. The best-fit [global P(c) = 7.2 x 10(-4)]BsmI-TaqI BT haplotype was found significantly more often in subjects without HT [12.2% vs. 3.7%; odds ratio (OR, 95% confidence intervals) = 0.28 (0.14-0.56), P(c) = 8 x 10(-4)], whereas the bT haplotype was significantly more frequent in individuals with HT [45.7% vs. 61.8%; OR = 1.91 (1.37-2.65), P(c) = 4 x 10(-4)]. Two extended BsmI-ApaI-TaqI RFLP haplotypes, the common baT [35.7 vs. 47.3%, OR = 1.63 (1.17-2.27), P(c) = 0.012] and rare BaT variants [6.5 vs. 1.2%, OR = 0.17 (0.06-0.55), P(c) = 1.2 x 10(-3)] were associated with HT, representing predisposing and protective haplotypes, respectively. In single-RFLP association analyses, only rs1544410 polymorphism was associated with HT phenotype (allelic P(c) = 0.0078) and appeared to function under the recessive model, with decreased risk of HT among the BB homozygotes [OR = 0.39 (0.21-0.7), P(c) = 0.0052] when compared to the reference b(+)-genotypes. These data suggest that common haplotypic variants within the VDR gene 3'-region previously linked to VDR mRNA expression and allelic imbalance could be associated with HT in the general population, and thus, may be involved in the pathogenesis of HT.

HPV testing for cervical cancer screening in Croatia

Opportunistic screening based on the Pap smear has been undertaken in Croatia since 1953. However, cervical cancer remains an important health problem in Croatia when compared to European countries with organised screening programmes. In Croatia, in addition to screening based on well established cytology, Human papillomavirus (HPV) testing is widely used as secondary test as a triage to borderline cytology and as a follow-up after treatment of severe cervical lesions. Many different approaches for HPV testing arose in Croatia over the last decade depending on the needs of each medical institution involved. Presently, there is an urgent need for better networking between the laboratories, the implementation of quality assessment and the adaptation of a uniform system of referring to and reporting of HPV testing. In conclusion, the best possible organisation for HPV testing would be essential for implementation of HPV testing as primary screening test in Croatia, an thus ultimately and hopefully, the more successful cervical cancer control.

Antitumor efficiency of novel fluoro-substituted 6-amino-2-phenylbenzothiazole hydrochloride salts in vitro and in vivo

The purpose of this study was to investigate antitumor activity of novel fluoro-substituted 6-amino-2-phenylbenzothiazole hydrochloride salts in vitro and in vivo. A novel series of hydrochloride or dihydrochloride salts of the novel 2-(fluoro-substituted phenyl)-6-aminobenzothiazoles (5-7) have been prepared in multistep synthesis starting from 3- or 4-fluorobenzaldehydes and 2-amino-5-nitrothiophenol and evaluated for their antiproliferative activity against human cervical (HeLa), breast (MCF-7), colon (CaCO-2), and laryngeal (Hep-2) carcinomas and against fibroblast cell lines (WI-38). Also, antitumor activity of these compounds was evaluated in vitro and in vivo against murine melanoma (B16-F10), fibrosarcoma (FsaR), and squamous cell carcinoma (SCCVII). The tested compounds were found to exert good cytotoxic activity in vitro. The cytotoxic effect was selective, cell specific, and dose dependent, between 33 microM for MCF-7 and 110 microM for WI-38. Benzothiazoles reduced de novo protein and DNA synthesis up to 75%. All examined benzothiazoles had significant antitumor activity in vivo against melanoma B16-F10, fibrosarcoma, and squamous cell carcinoma. The best therapeutic results were achieved when therapy started 7 days after tumor cell implantation and when benzothiazoles were given repeatedly five times every 2 days, i.e., on day 7, 9, 11, 13, and 15 after transplantation of tumor cells.

Tumor-Cell-Targeted Methionine-enkephalin Analogues Containing Unnatural Amino Acids: Design, Synthesis, and in Vitro Antitumor Activity

A series of new peptides (8-25) containing different unnatural amino acids of the adamantane type (1-6), was synthesized. Possible cytotoxic activity on human cervical adenocarcinoma (HeLa), larynx carcinoma (HEp-2), colon carcinomas (HT-29, Caco-2), poorly differentiated cells from lymph node metastasis of colon carcinoma (SW-620), mammary gland adenocarcinoma (MCF-7), and melanoma (HBL) cells were tested by the MTT assay. The results were compared with the effect of methionine-enkephalin (Tyr-Gly-Gly-Phe-Met, or opioid growth factor, OGF), and its shorter N-terminal fragments. Peptide analogues containing C(alpha alpha)-dialkylated glycine (Aaa1, 1) or C(alpha)-alkylated glycine (Aaa2, 2) amino acid residues showed antitumor activity against melanoma, larynx carcinoma, colon carcinomas, and colon metastasis cell lines in vitro. The pentapeptide Tyr-(R,S)-Aaa2-Gly-Phe-Met (18) was the most effective analogue especially against the most antitumor drug-resistant cell lines HEp-2 and SW-620. Apoptosis as a mode of cell death was confirmed in these tumor cells after exposure to pentapeptide 18.

The influence of cell growth media on the stability and antitumour activity of methionine enkephalin

Studies with cultured tumour cell lines are widely used in vitro to evaluate peptide-induced cytotoxicity as well as molecular and biochemical interactions. The objectives of this study were to investigate the influence of the cell culture medium on peptide metabolic stability and in vitro antitumour activity. The degradation kinetics of the model peptide methionine enkephalin (Met-E, Tyr-Gly-Gly-Phe-Met), demonstrated recently to play an important role in the rate of proliferation of tumour cells in vitro and in vivo, were investigated in cell culture systems containing different amounts of fetal bovine serum (FBS). The influence of enzyme inhibitors (bestatin, captopril, thiorphan) on the Met-E degradation was also investigated. The results obtained in the Dulbecco's modified Eagle medium containing 10% FBS indicated a rapid degradation of Met-E (t(1/2) = 2.8 h). Preincubation of the medium with a mixture of peptidase inhibitors reduced the hydrolysis of Met-E, as shown by the increased half-life to 10 h. The in vitro activity of Met-E against poorly differentiated cells from lymph node metastasis of colon carcinoma (SW620) and human larynx carcinoma (HEp-2) cells was determined. Tumour cells were grown for 3 weeks prior to the experiment in a medium supplemented with 10%, 5% or 2% FBS. Statistically significant to mild or no suppression of cell proliferation was observed in all cultures. In both cell lines, a significant suppression of cell growth by a combination of peptidase inhibitors and Met-E, compared with cells exposed to the peptide alone and cells grown in the absence of Met-E, was observed. This study indicated that caution must be exercised in interpreting the antiproliferative effects of peptide compounds in conventional drug-response assays.

Effects of inhalation anesthetics halothane, sevoflurane, and isoflurane on human cell lines

Cytotoxic and antiproliferative effects of halothane, isoflurane, and sevoflurane in anesthetic doses on human colon carcinoma (Caco-2), larynx carcinoma (HEp-2), pancreatic carcinoma cells (MIA PaCa-2), poorly differentiated cells from lymph node metastasis of colon carcinoma (SW-620), and normal fibroblasts were investigated. Cells were exposed to anesthetic gas mixture consisting of O(2): N2O (35:60 vol.%), halothane (1.5 vol.%) or isoflurane (2.0 vol.%) or sevoflurane (3.0 vol.%), and CO(2) (5 vol.%), for 2, 4, and 6 h. Cytotoxicity of anesthetics was analyzed by validated tetrazolium dye assay MTT test. All anesthetics expressed cytotoxic effects on treated tumor cells in time and cell line dependent manner. Growth suppression in cells exposed to halothane was enhanced in HEp-2 (to 67.7%), Caco-2 (to 76.3%), and SW620 cells (to 80.9%), and was minimal in normal fibroblasts (to 89.4%). Antiproliferative activity of halothane was measured via radioactive precursors incorporation assay. In Caco-2 cells treated by halothane, decrease in DNA synthesis (52.4%, p=0.001), RNA synthesis (39.2%, p<0.001), and protein synthesis (19.2%, p=0.004) was observed. In HEp-2 cells, DNA and RNA syntheses were decreased to 72.5% and 79.9%, whereas protein synthesis was 14.0% of control (p<0.001). In SW620 cells, protein synthesis after 4 h was 24.4% (p=0.007). A DNA fragmentation was observed in Caco-2 and MIA PaCa-2 cells. Exposition of phosphatidylserine on outer lipid bilayer plasma membrane of tumor cell treated by halothane proved apoptosis as mode of cell death.

Association of vitamin D receptor gene polymorphism with susceptibility to Graves' disease in Eastern Croatian population: case-control study

AIM

To evaluate the effect of vitamin D3 receptor (VDR) gene BsmI/ApaI/TaqI restriction fragment length polymorphisms on Graves' disease susceptibility in a subset of patients from Eastern Croatia.

METHODS

Graves' disease patients (n=110) and ethnically matched euthyroid controls (n=99) with no clinical evidence or family history of thyroid or autoimmune diseases were genotyped for VDR gene polymorphisms by BsmI/ApaI/TaqI endonuclease digestion after polymerase chain reaction amplification with sequence-specific primers. Data were analyzed by chi-square-test, and crude odds ratios (OR) with 95% confidence interval (95% CI) were calculated.

RESULTS

The ApaI "AA" (14.5% vs 30.3%, patients vs controls, respectively, OR=0.39, 95% CI [0.2-0.77], P=0.01) and BsmI "BB" (7.3% vs 23.2%, OR=0.26 [0.11-0.61], P=0.002) genotypes were significantly underrepresented in patients, whereas ApaI "aa" (28.2% vs 9.1%, OR=3.92 [1.76-8.74], P=0.001) and TaqI "TT" (51.8% vs 31.3%, OR=2.36 [1.34-4.16], P=0.004) genotypes were significantly more frequent in patients than controls. The genotype combination, which conferred the strongest protection against Graves' disease, was "BBAAtt" (2.7% vs 17.2%, OR=0.14 [0.04-0.48], P=0.001).

CONCLUSION

These findings suggest that VDR gene BsmI/ApaI/TaqI polymorphisms are associated with Graves' disease susceptibility in a subset of patients from Eastern Croatia. The ApaI and BsmI "AA" and "BB" genotypes, respectively, as well as combined "BBAAtt" genotype, appeared to confer protection against Graves' disease, whereas ApaI "aa" and TaqI "TT" genotypes were associated with an increased risk for Graves' disease. However, the true mechanisms of association remain to be elucidated.

Metabolic effects of novel N-1-sulfonylpyrimidine derivatives on human colon carcinoma cells

Novel N-1-sulfonylpyrimidine derivatives have a strong antiproliferative activity and an ability to induce apoptosis in treated tumor cells. The purpose of this study was to elucidate the effects of two N-1-sulfonylpyrimidine nucleobases on catalytic activity of tumor cells' enzymes involved in DNA and RNA synthesis, and in de novo and salvage pyrimidine and purine syntheses. Investigations were performed in vitro on colon carcinoma cells (Caco2). The biosynthetic activity of the tumor cells' enzymes was determined using sensitive radio-assays. Enzyme activity in treated cells was calculated relative to untreated control cells. Both of the investigated compounds, 1-(p-toluenesulfonyl) cytosine (TsC) and 5-bromo-1-(methanesulfonyl) uracil (BMsU) inhibited activities of specific enzymes involved in nucleic acid synthesis. BMsU strongly inhibited activities of DNA polymerase alpha (53%), thymidine kinase (68%), thymidilate synthase (43%), and ribonucleotide reductase (46%). De novo biosynthesis of pyrimidine and purine was reduced by 20%. TsC was able to inhibit RNA polymerase (37%), orotate phosphoribosyltransferase (39%), uridine kinase (44%), ribonucleotid reductase (47%), and de novo purine synthesis (61%). Antitumor activity of 1-(p-toluenesulfonyl) cytosine (TsC) and 5-bromo-1-(methanesulfonyl) uracil (BMsU) is closely associated with their inhibitory activity on enzymes that play an important role in the metabolism of tumor cells.

Anaesthetic implications of anticancer chemotherapy

In anaesthetic practice we deal with cancer patients who are scheduled for operations on tumours or other manifestations of malignant disease. Those patients are often debilitated and have significant weight loss accompanied with hypoproteinaemia, anaemia and coagulation disorders. Oncological patients usually present to the anaesthetist before tumour disease surgery, but they are also candidates for elective operations (e.g. hernia repair) and urgent/emergency surgery (e.g. trauma, fractures and ileus). Chemotherapeutic agents given to these patients are potentially noxious, can affect the conduct of anaesthesia and, furthermore, may aggravate the patient's condition. In this review the most commonly used cytostatic drug regimens and their common side-effects are listed. Some preclinical studies on anaesthetic and cytostatic drug metabolism and interactions are emphasized, as well as clinically relevant perioperative alterations that may affect anaesthetic management in cancer patients. An anaesthetist may have to modify a routine anaesthetic regimen in cancer patients especially if anticancer chemotherapeutics were given. Clinically silent toxic drug effects may become apparent during operation, trauma or in the early postoperative course in such patients. Altered reactions to commonly used anaesthetics in patients receiving chemotherapeutics and an impaired stress reaction may occur in such patients. Special attention must be drawn to protection against opportunistic infections.

Antineoplastic activity of novel N-1-sulfonypyrimidine derivatives

We evaluated the potential activity of novel N-1-sulfonyl derivatives of pyrimidine bases uracil and cytosine on pancreatic carcinoma cells (MIAPaCa2), colon carcinomas cells (HT-29, CaCo2), cervical carcinoma cells (HeLa) and poorly-differentiated cells from lymph node metastasis of colon carcinoma (SW-620). The cytotoxicity of N-1-sulfonylpyrimidine derivatives was analyzed with the MTT cell survival assay and their antiproliferative activity was measured via radioactive precursors incorporation assay. The N-1-sulfonylpyrimidine derivatives affected the growth of all examined cell lines at concentrations of 10(-8)-10(-5) M, by 25-70%. Growth inhibition depended on the tumor cell line type and the concentration of investigated compounds. The compounds 2, 4, 7, 8 and 9 inhibited DNA, RNA and protein synthesis in CaCo2, MIAPaCa2 and HeLa cells. The exposure of tumor cells in vitro to compounds 2, 4, 7, 8, 9, 10 and 11, at the 10(-6) M concentration, caused both morphological (condensation of chromatin, cell shrinkage), as well as biochemical changes (ladder pattern of DNA fragmentation and exposure of phosphatidylserine on outer lipid bilayer plasma membrane) characteristic of apoptosis. After 24 hours of the N-1-sulfonylpyrimidine derivative application, the p53 oncoprotein expression could not be detected by immunocytochemical analysis. On the basis of present results it can be concluded that novel N-1-sulfonylpyrimidine derivatives are promising antitumor agents with a strong antiproliferative activity and an ability to induce apoptosis in treated tumor cells.

In vitro cytotoxicity of three 4,9-diazapyrenium hydrogensulfate derivatives on different human tumor cell lines

DNA intercalating agents interfere with DNA's role as a template in replication and transcription by inserting an intercalator molecule between adjacent base pairs. We synthesized three potential novel intercalators, 4,9-diazapyrenium hydrogensulfate derivatives: 5, 10-diphenyl-4,9-dimethyl-4,9-diazapyrenium hydrogensulfate (FDAP), 4, 9-dimethyl-4,9-diazapyrenium hydrogensulfate (GDAP) and 2,4,7, 9-tetramethyl-4,9-diazapyrenium hydrogensulfate (MDAP) and tested their biological effects in vitro on four human tumor cell lines (SKBr3: breast carcinoma, HeLa: cervical carcinoma, CaCo2: colon carcinoma and SW620: poorly differentiated cells from lymph node metastasis of colon carcinoma). Cytotoxic effects on cell growth and viability were determined using tetrazolium dye (MTT) assay. DNA synthesis and proliferation of treated cells were studied by the [(3)H]-thymidine incorporation test. DNA fragmentation was analyzed by agarose gel electrophoresis. The growth inhibitory effect was cell-specific and dose-dependent. The most pronounced antiproliferative effect was observed on SKBr3 cells for FDAP (10(-5) M) 91.8%, for MDAP (10(-5) M) 85.3% and on SW620 cells for GDAP (10(-5) M) 65.3%. The DNA ladder fragmentation of treated HeLa and SKBr3 cells, as a hallmark of apoptosis, was observed. Based on specific DNA fragmentation, morphological changes (reduced cell volume, round cell shape, condensed chromatin) and growth inhibition of treated human tumor cells we conclude that tested substances induced apoptotic cell death.

4,9-diazapyrenium dications induce apoptosis in human tumor cells

We investigated the antiproliferative effects of two planar 4,9-diazapyrenium hydrogenasulphates against human malignant MiaPaCa 2 (pancreatic carcinoma), Hep 2 (laryngeal carcinoma) and human normal fibroblasts (WI 38) cell lines. The tested compounds were very potent in inhibiting the growth of the treated cell lines. Treatment with molar concentrations of the substances (10(-4)-10(-7) M) caused growth inhibition by more than 50%. The morphological changes of treated cells were also observed. Cells became smaller, with condensed chromatin and fragmented nuclei, the characteristics of dying cells. The identification of DNA-fragmentation and the appearance of chromatin aggregation leads us to assume the tested substances induced apoptosis of the investigated tumor cell lines.