Microbiological quality of petfood in Poland.

From epidemiological and safety point of view, petfoods produced from edible and non-edible animal by-products should be safe for slaughter animals, owners of these pets and environment. Domestic animals are recognized as highly important reservoir of pathogenic microorganisms for man. The close contact of people and especially children with pets may constitute a serious hazard for their health. Taking these aspects into account, the study was undertaken in which 2271 dried and 18 canned petfood samples were examined. Moreover, 14, 90, 23 and 22 samples of petfoods were examined for presence or number of Clostridium sp., Enterobacteriaceae, total plate count, and yeast and moulds, respectively. Salmonella was isolated from 22 (1%) out of 2271 dried petfood samples examined. Number of Enterobacteriaceae was higher than 300 cfu/g, i.e. the allowed maximum level was found in 9 (10%) samples examined. The rest of microbiological quality parameters did not exceed the allowed values.

Antitumor activity of bacteriophages in murine experimental cancer models caused possibly by inhibition of beta3 integrin signaling pathway.

Bacteriophages (phages) as bacterial viruses are generally believed to have no intrinsic tropism for mammalian cells. In this study the interactions between phages and various eukaryotic cells were investigated. Binding of phages to the membranes of cancer and normal blood cells was observed. Moreover, it was shown that the wild-type phage T4 (wtT4) and its substrain HAP1 with enhanced affinity for melanoma cells inhibit markedly and significantly experimental lung metastasis of murine B16 melanoma cells by 47% and 80%, respectively. A possible molecular mechanism of these effects, namely a specific interaction between the Lys-Gly-Asp motif of the phage protein 24 and beta3-integrin receptors on target cells is proposed. It was also shown that anti-beta3 antibodies and synthetic peptides mimicking natural beta3 ligands inhibit the phage binding to cancer cells. This is in line with the well-described beta3 integrin-dependent mechanism of tumor metastasis. It is concluded that the blocking of beta3 integrins by phage preparations results in a significant decrease in tumor invasiveness.

Potentiation of the antiproliferative effect in vitro of doxorubicin, cisplatin and genistein by new analogues of vitamin D.

Numerous vitamin D3 analogues have been synthesised in recent years in order to obtain compounds with a favourable biological and therapeutic (antipsoriatic and/or antitumour) activity. Our results showed that pre-treatment for 72 hours of HL-60 human promyelocytic leukaemia cells with calcitriol or its new analogues significantly potentiated their sensitivity to the antiproliferative effect in vitro of cisplatin, doxorubicin or genistein. Moreover, for all cytotoxic agents tested a synergistic antiproliferative effect was observed. This effect was expressed as a significant decrease of the ID50 (inhibitory dose 50%) values for each cytotoxic agent applied after pretreatment with calcitriol or its analogues of HL-60 cells in comparison with the effect of cytotoxic agent applied alone. The observed in vitro potentiated antiproliferative effect of cytotoxic drugs used in combination with vitamin D or its analogues may raise the question as to whether such an effect could be expected in the in vivo situation.

Antiproliferative activity in vitro of new malatoplatinum(ll) complexes.

The results of studies on antiproliferative activity in vitro of nine new platinum(II) complexes against cells of eight human and six murine neoplastic cell lines are described. New complexes with the anionic rest originating from enantiomeric forms of hydroxydicarboxylic malic acid were synthesized to obtain agents with increased water solubility and decreased toxicity. Three compounds, coded 1-3, with ethylenediamine as a neutral ligand, showed cytotoxic activity against 12 out of 14 target cell lines. Their cytotoxic activity was similar or even slightly higher than that of the reference carboplatin. The remaining six compounds, coded 4-9, with 1-alkylimidazole as a neutral ligand, revealed rather low cytotoxic activity, and only against the cells of the human bladder cancer cell line Hu1703He, ovarian cancer cell line OAW-42 and mouse leukemia P388. Most of them appeared to be negative against all other cell lines. No compounds, including reference carboplatin, showed any cytotoxicity against the cells of the T47D human breast cancer cell line or B16F-10 mouse melanoma cell line. The results obtained are in accordance with common opinion, i.e. that the presence of neutral amine ligands with NH groups is required for the cytotoxic activity of platinum complexes. Compounds with a primary amine (ethylenediamine) showed higher cytotoxic activity in vitro than complexes with a tertiary amine (1alkylimidazole).

Antiproliferative activity in vitro of side-chain analogues of calcitriol against various human normal and cancer cell lines.

The antiproliferative in vitro activity of side-chain modified analogues of 1,25-dihydroxyvitamin D3 was examined in order to select compounds with potential antitumour activity. Analogues PRI-1906, PRI-1907, PRI-1909, PRI-2191, PRI-2192, PRI-2193 and PRI-2194 were examined for their antiproliferative activity in vitro against a spectrum of various human cancer cell lines using the MTT technique. In addition, analogues PRI-1906 and PRI-2191 were screened against cells of human leukaemia HL-60 line and against normal human skin fibroblasts. Calcitriol and these two analogues revealed strong antiproliferative activity against these two targets with maximal growth inhibition of 68% for HL-60 cells and of 60% for fibroblasts, and this effect was dose dependent. All analogues tested, except PRI-1909, revealed antiproliferative activity against human carcinoma cell lines of breast origin applied, namely against T47D and MCF-7. The maximal growth inhibition of 49% for T47D cell line and 39% for MCF-7 line was observed, and this effect was dose dependent. The inhibitory doses of the analogues tested were compared with the indices for calcitriol. Analogue PRI-1906 revealed the strongest antiproliferative activity against these four target cell lines (HL-60, fibroblasts, MCF-7, and T47D). The novel analogues of calcitriol, similarly to calcitriol, appeared to be not active against other human cancer cell lines tested (including those originated from lung, colon, prostate, urinary bladder, ovary, pancreas, stomach and kidney) revealing an antiproliferative activity not exceeding 20%. The mechanism of the observed antiproliferative effect of calcitriol and its analogues in vitro remains unclear, however, it may be related to their effect on cell differentiation. The appearance of antigen CD14 and CD11b expression after exposure to calcitriol and its new analogues confirmed their effect on cell differentiation.

Human in vitro cell lines verification by minisatellite DNA restriction fragment length polymorphism.

Four families of human in vitro cell lines were tested for minisatellite restriction fragment length polymorphism (RFLP) using multilocus probes MZ1.3 and/or 33.15 after digestion of DNA with restriction enzymes HinfI or HaeIII. These results confirmed that (i) the RFLP pattern is relatively stable in established cell lines and, therefore, could be used as a specific marker of a cell line identity, (ii) the use of MZ1.3 and 33.15 probes permits the identification of hybridomas and (iii) one of the cell lines tested, a lymphoblastoid cell line HAJ, may possess a hot spot of mutation.

Cytostatic activity in vitro of some new cyclophosphazene oligomers.

Cytostatic activity of newly synthesized aziridinyl substituted cyclophosphazenes was tested in two in vitro systems. First, the compounds were tested by total cell protein inhibition test on human KB tumor cell line. Selected active compounds were tested in a clonogenic assay on murine L1210 leukemia cells. Out of 18 compounds tested, 12 were newly synthesized, 3 were their substrates and 4 were compounds with known cytostatic activity, used as a positive controls. Four of the newly synthesized compounds, designated with symbols: BANF-4Az, BBNF-4Az. T-oFDA-Az and W-10 revealed cytostatic activity for KB cells (ED50 = 3.4-19 micrograms/mL) and were tested in clonogenic assay. One of these compounds, namely T-oFDA-Az was subsequently selected for the further steps of screening for antitumor activity in animal tumor models.

Cytostatic activity in vitro of phosphonic acid derivatives.

Cytostatic activity of 48 new amino acid analogs and derivatives of phosphonic acid type was tested against KB cell line in vitro. The tests were performed according to the recommended international protocol for screening of chemical agents against tissue culture system. Three of the compounds tested: No. No, 29, 33 and 32 revealed cytostatic activity at the concentrations: 63, 150, and 180 micrograms ml-1 respectively (ID50).