Ultra-sensitive solid-phase Microextraction-Gas Chromatography-Mass spectrometry determination of polycyclic aromatic hydrocarbons in snow samples using a deep cavity BenzoQxCavitand.

A very sensitive and selective solid-phase microextraction-gas chromatography-mass spectrometry method based on the use of a deep cavity BenzoQxCavitand as innovative coating was developed and validated for the simultaneous determination of the 16 US-EPA priority pollutants polycyclic aromatic hydrocarbons (PAHs) in snow samples at ultra-trace levels. The presence of a 8.3 Å deep hydrophobic cavity allowed the engulfment of all the 16 PAHs, providing enhanced selectivity also in presence of interfering aromatic pollutants at high concentration levels. Validation proved the reliability of the method for the determination of the investigated compounds achieving detection limits in the 0.03-0.30 ng/L range, good precision, with relative standard deviations <18% and recovery rates in the 90.8(±2.1)%-109.6(±1.0)%. The detection of low-molecular weight PAHs in snow samples from Antarctica and Alps confirms the widespread occurrence of these compounds, thus assessing the impact of anthropogenic activities onto the environment.

LMNA gene mutation as a model of cardiometabolic dysfunction: from genetic analysis to treatment response.

AIM: This report highlights the metabolic, endocrine and cardiovascular comorbidities in a case of familial partial lipodystrophy (FPLD), and also evaluates the efficacy and safety of metformin therapy. METHODS: Mutational analysis was carried out of the LMNA gene in a teenage girl with an FPLD phenotype. Insulin resistance, sex hormones and metabolic parameters were also evaluated, and echocardiography, electrocardiography and 24-h blood pressure monitoring were also done. RESULTS: The patient showed atypical fat distribution, insulin resistance and hypertrophic cardiomyopathy. Physical examination revealed muscle hypertrophy with a paucity of fat in the extremities, trunk and gluteal regions, yet excess fat deposits in the face, neck and dorsal cervical region. LMNA sequencing revealed a heterozygous missense mutation (c.1543A>G) in exon 9, leading to substitution of lysine by glutamic acid at position 515 (K515E). Moderate hypertension and secondary polycystic ovary syndrome were also assessed. Treatment with metformin resulted in progressive improvement of metabolic status, while blood pressure values normalized with atenolol therapy. CONCLUSIONS: Very rapid and good results with no side-effects were achieved with metformin therapy for FPLD. The association of an unusual mutation in the LMNA gene was also described.

TLR4 and NOD2/CARD15 genetic polymorphisms and their possible role in gastric carcinogenesis.

UNLABELLED: The aim of this study was to evaluate the role of TLR4 and NOD2/CARD15 genes in gastric carcinogenesis. PATIENTS AND METHODS: We investigated the allelic frequencies of TLR4 (D299G and T399I) and NOD2/CARD15 (R702W, G908R, and L1007finsC) SNPs in 87 asymptomatic serologically H. pylori-positive individuals (Group I), in 63 patients with antrum-predominant gastritis (Group II) and in 60 patients with corpus-predominant gastritis or pangastritis (Group III). RESULTS: There was significant difference in allelic frequencies of TLR4 D299G SNP in Group II (p=0.02; OR 2.97) as well as in Group III (p=0.001; OR 4.80). Significant difference of T399I SNP allele frequency was only found in Group III (p=0.009; OR 3.73). The allele frequencies of NOD2/CARD15 G908R and of L1007insC SNP were higher in Group III (p=0.003, OR 5.18; p=0.03; OR 3.66, respectively). CONCLUSION: TLR4 and NOD2/CARD15 genes are associated with high risk Group III patients and, therefore, they appear to play a role in gastric carcinogenesis.

Experimental model of asymmetric brain ischemia and reperfusion in the rat.

BACKGROUND: In this experimental study is illustrated an original model of cerebral asymmetric ischemia and reperfusion in the rat, induced by unilaterally elevating ICP and clamping the corresponding common carotid artery, that allows a direct comparison of the two brain hemispheres, one normal and the other ischemic, of the same animal. METHODS: The experimental procedure consisted in grafting two screws through the skull on the right side of the sagittal suture, one of them being connected to a Queckenstedt manometer for monitoring ICP variations. A nitroprusside solution (1 mg/ml administered through the femoral vein at a flow rate of 0.103 ml/min) was infused to achieve a significant drop of MABP. At this time point, animals were subjected to 5 min of ischemia and 10 min of reperfusion induced by clamping and declamping the right common carotid artery. During the whole period of ischemia and reperfusion ICP and MABP were constantly monitored. In order to provide an outlook on the metabolic alterations of brain tissue occurring during ischemia and reperfusion phenomena, several biochemical parameters of cellular energy metabolism and of oxygen radical-induced membrane damage were determined by a sensitive and reproducible HPLC method on perchloric acid tissue extracts. RESULTS AND CONCLUSIONS: The validity of the present model was supported by the finding of significant intrahemispheric differences in the concentration of several compounds considered as biochemical markers of tissue injury, such as adenosine 5'-triphosphate catabolites and malondialdehyde, this last indicating the damaging action of oxygen free radicals on cell membrane phospholipids.

Interaction of cultured mammalian cells with [125I] diphtheria toxin.

The characteristics of cell adsorption and pinocytotic uptake of diphtheria toxin by several mammalian cell types were studied. Purified toxin iodinated by a solid-state lactoperoxidase method provided preparations of high specific activity and unaltered biological activity. Dephtheria toxin-sensitive HEp-2 cells and guinea pig macrophage cultures were compared with resistant mouse L-929 cells. At 37 C the resistant cells in monolayer adsorbed and internalized [125I] toxin to a greater extent than did the HEp-2 cell cultures; no significant differences were observed at 5 C. Ammonium chloride protection levels did not alter uptake of toxin by either L-929 OR HEp-2 cells. Biological activity of the iodinated toxin, however, was negated provided the presence of ammonium chloride was maintained. The ammonium salt appears to maintain toxin in a state amenable to antitoxin neutralization. Guinea pig macrophages internalized iodinated toxin to a level 10 times greater than the established cell lines. In spite of the increased uptake of toxin by the endocytic cells, ammonium chloride prevented expression of toxicity. In an artificial system, toxin adsorbed to polystyrene latex spheres and internalized by guinea pig macrophages during phagocytosis did express biological activity. Ammonium chloride afforded some but not total protection against toxin present in the phagocytic vacuoles. The data suggest that two mechanisms of toxin uptake by susceptible cells may be operative. Toxin taken into the cell by a pinocytotic process probably is not ordinarily of physiological significance since it is usually degraded by lysosomal enzymes before it can reach cytoplasmic constituents on which it acts. When large quantities of toxin are pinocytized, toxicity may be expressed before enzymatic degradation is complete. A more specific uptake involving direct passage of the toxin through the plasma membrane may be the mechanism leading to cell death in the majority of instances.