Cell crowding induces interferon regulatory factor 9, which confers resistance to chemotherapeutic drugs

The mechanism of multicellular drug resistance, defined as the reduced efficacy of chemotherapeutic drugs in solid tumors is incompletely understood. Here we report that colon carcinoma cells cultured as 3D microtissues (spheroids) display dramatic increases in the expression of a subset of type I interferon‐(IFN)‐stimulated genes (ISGs). A similar gene signature was associated previously with resistance to radiation and chemotherapy, prompting us to examine the underlying biological mechanisms. Analysis of spheroids formed by different tumor cell lines and studies using knock‐down of gene expression showed that cell crowding leads to the induction of IFN regulatory factor‐9 (IRF9) which together with STAT2 and independently of IFNs, is necessary for ISG upregulation. Increased expression of IRF9 alone was sufficient to induce the ISG subset in monolayer cells and to confer increased resistance to clinically used cytotoxic drugs. Our data reveal a novel mechanism of regulation of a subset of ISGs, leading to drug resistance in solid tumors.     

Antimicrobial,anti-inflammatory,anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil

The root of Carlina acanthifolia All. (Asteraceae) has been traditionally used in the treatment of various disorders including stomach and skin diseases. We studied antimicrobial, anti-inflammatory, anti-ulcer and antioxidant activities of Carlina acanthifolia root essential oil, in order to validate some of the ethnopharmacological claims. Antimicrobial activity was tested on 15 bacteria and three strains of fungi using the agar diffusion and broth microdilution methods. In assessing anti-inflammatory activity the carrageenan-induced rat paw oedema test was used, while ethanol-induced stress gastric ulcer test in rats was used in testing anti-ulcer activity. Antioxidant properties were evaluated trough the effect of the essential oil on lipid peroxidation (TBA assay) and its capability of quenching 2,2-diphenyl-1-picrylhydrazyl (DPPH) and OH radicals. The oil expressed significant antimicrobial activity, being the most active against Gram (+) bacteria: Streptococcus pyogenes, Enterococcus faecalis, Bacillus subtilis and against Candida albicans. In all applied concentrations, Carlina acanthifolia root essential oil reduced carrageenan-induced rat paw oedema in dose-dependent manner, achieving high degree of anti-inflammatory activity. The effect was comparable with that of indomethacin used as a reference drug. In the ethanol-induced stress gastric ulcer test in rats, it was shown that the tested essential oil produced significant dose-dependent gastroprotective activity. The results also pointed out substantial and dose-dependent antioxidant activity of the investigated essential oil, with carlina oxide as the main antioxidant component.     

Gifted and Average Children's Relations with their Parents

This study investigates interpersonal relations of gifted adolescents with their parents. Quality of and satisfaction with parents' relations are examined by questionnaires. Subjects are intellectually and academically gifted and average pupils of Yugoslav secondary schools (14;6-18;11 years). Gifted and average pupils do not report significant differences on two applied measures of relations with their parents. But, pupils from special programs are less satisfied with their parents' relations than pupils from regular programs, and gifted male adolescents are less satisfied than gifted female adolescents. It happens that older adolescents, no matter they are gifted or not, experience less positive relations with their parents and are less satisfied with these relations than younger adolescents. It is concluded that the most powerful characteristic of pupils among measured is their age. Some explanations of research findings are given in the framework of the regular developmental processes going on during the period of middle adolescence.     

Unilateral nephrectomy causes an early abrupt decrease in plasma arginine and simultaneous reduction in glomerular filtration rate in living kidney donors

Objectives

Living donor kidney transplantation is regarded as beneficial to allograft recipients and not particularly detrimental to the donors. Recently we have documented a reduced glomerular filtration rate (GFR) in living kidney donors (LKDs). Considering kidneys as essential for l-arginine (Arg) metabolism, in the present study we analyzed plasma Arg and related compounds comparing them with the function of remaining kidney in LKDs after donation.

Design and methods

We analyzed GFR, plasma Arg, asymmetric dimethylarginine (ADMA), citrulline (Cit), glutamine (Gln), ornithine (Orn), phenylalanine (Phe), tyrosine (Tyr), thiobarbituric acid reactive substances (TBARS), urea, creatinine, nitrite, nitrate and their sum (NOx) in blood samples taken from LKDs before, immediately after (0-time) and 1, 2, 3, 7 and 14 days following surgery.

Results

Gradual and moderate creatinine increase and albumin decrease were associated with decreased GFR. An abrupt decrease in Arg occurred, staying below baseline level throughout the 14 days. Also decreases in Gln, Cit, Orn, increase in Phe and TBARS, and unaltered ADMA, nitrite and NOx concentrations were obtained. Despite increased net protein catabolism (indicated by elevated Phe/Tyr ratios) lack of Arg, suggested by decreased molar Arg/Phe ratios, occurred. Decreased molar Arg/Gln suggests an early but transient decrease in Arg synthesis.

Conclusion

Unilateral nephrectomy causes an early abrupt decrease in plasma arginine and reduction in glomerular filtration rate in LKDs that was associated with increased net protein breakdown in the peripheral tissues and elevated oxidative damage, which has to be considered in their therapy.     

Simultaneous LC determination of tiazofurin,its acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide in biological samples

A rapid and sensitive HPLC-RP method for simultaneous determination of tiazofurin, its 5'-O acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide was developed and validated. The method allowed determination and quantification of nanomolar quantities of these substances in cell extracts of treated cells, and was also used in kinetic studies of cellular uptake of tiazofurin and its esters from the cultivation medium. Separation of the analyzed substances from unidentified peaks from both biological materials was achieved by gradient elution, thus reducing the possibility of interference. The mobile phase consisted of a 0.1 M sodium-hydrogen phosphate, pH 5.1 and methanol. Run time was 22 min, with 5 min equilibration time.