Observations sur la significativité de la coloration aux Alcians pour les mucopolysaccharides

Resumé Les Auteurs, à la suite d'une serie des récherches sur la coloration au bleu Alcian de la cartilage, on pu démontrer que la signaléticité de ce colorant basique envers les mucopolysaccharides est due à la interférence inhibitive avec une fraction protéique présente en grande quantité dans les structures non-mucopolysaccharidiques ionisées au pH de utilisation (2,4) (DNA, collagéne etc.), fraction bien soluble dans les solutions salines et dans l'acide sulphurique 1 M, mais peu soluble dans l'acide acétique 3%.L'asportation de cette substance à l'aide de dits solvants ou de la digestion à la pepsine, augmente la colorabilité des mucopolysaccharides, mais diminue ou abolit la signaléticité.Sur cette donné, les Auteurs expliquent les differentes anomalies de la méthode aux Alcians.

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Observations about electivity of Alcian staining of mucopolysaccharides

Summary The Authors proved, in the course of a general investigation about the Alcian blue staining of cartilage, that the specificity of this dye is due to its inability of staining in the presence of a proteic fraction, which is present in a greater amount in the non-glycid structures containing ionized groups at 2,4 pH: i.e. collagen, DNA etc.This protein is easily soluble in various salt solutions and in 1 M sulphuric acid, but insoluble in 3% acetic acid. Removal of this protein by these agents or by peptic digestions result in increasing the mucopolysaccharides staining, but in decreasing or suppressing electivity.Differents abnormalities of Alcian method are explained by the Authors in this way.

     

Neoadjuvant Sequential Docetaxel Followed by High‐Dose Epirubicin in Combination With Cyclophosphamide Administered Concurrently With Trastuzumab. The DECT Trial

To report the results of the DECT trial, a phase II study of locally advanced or operable HER2‐positive breast cancer (BC) treated with taxanes and concurrent anthracyclines and trastuzumab. Eligible patients (stage IIA‐IIIB HER2‐positive BC, 18–75 years, normal organ functions, ECOG ≤1, and left ventricular ejection fraction (LVEF) ≥55%) received four cycles of neoadjuvant docetaxel, 100 mg/m² intravenously, plus trastuzumab 6 mg/kg (loading dose 8 mg/kg) every 3 weeks, followed by four 3‐weekly cycles of epirubicin 120 mg/m² and cyclophosphamide, 600 mg/m², plus trastuzumab. Primary objective was pathologic complete response (pCR) rate, defined as ypT0/is ypN0 at definitive surgery. We enrolled 45 consecutive patients. All but six patients (13.3%) completed chemotherapy and all underwent surgery. pCR was observed in 28 patients (62.2%) overall and in 6 (66.7%) from the inflammatory subgroup. The classification and regression tree analysis showed a 100% pCR rate in patients with BMI ≥25 and with hormone negative disease. The median follow up was 46 months (8–78). Four‐year recurrence‐free survival was 74.7% (95%CI, 58.2–91.2). Seven patients (15.6%) recurred and one died. Treatment was well tolerated, with limiting toxicity being neutropenia. No clinical cardiotoxicity was observed. Six patients (13.4%) showed a transient LVEF decrease (<10%). In one patient we observed a ≥10% asymptomatic LVEF decrease persisting after surgery. Notwithstanding their limited applicability due to the current guidelines, our findings support the efficacy of the regimen of interest in the neoadjuvant setting along with a fairly acceptable toxicity profile, including cardiotoxicity. Results on BMI may invite further assessment in future studies. J. Cell. Physiol. 231: 2541–2547, 2016. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.     

Antimicrobial Combinations against Pan-Resistant Acinetobacter baumannii Isolates with Different Resistance Mechanisms

The study investigated the effect of antibiotic combinations against 20 clinical isolates of A. baumannii (seven colistin-resistant and 13 colistin-susceptible) with different resistance mechanisms. Clinical data, treatment, and patient mortality were evaluated. The following methods were used: MIC, PCRs, and outer membrane protein (OMP) analysis. Synergy was investigated using the checkerboard and time-kill methods. Clonality was evaluated by PFGE. Based on clonality, the whole genome sequence of six A. baumannii isolates was analyzed. All isolates were resistant to meropenem, rifampicin, and fosfomycin. OXA-23 and OXA-143 were the most frequent carbapenemases found. Four isolates showed loss of a 43kDa OMP_. The colistin-susceptible isolates belonged to different clones and showed the highest synergistic effect with fosfomycin-amikacin. Among colistin-resistant isolates, the highest synergistic effect was observed with the combinations of colistin-rifampicin followed by colistin-vancomycin. All colistin-resistant isolates harbored bla_OXA-23-like and belonged to CC113. Clinical and demographic data were available for 18 of 20 patients. Fourteen received treatment and eight patients died during treatment. The most frequent site of infection was the blood in 13 of 14 patients. Seven patients received vancomycin plus an active drug against A. baumannii; however, mortality did not differ in this group. The synergistic effect was similar for colistin-susceptible isolates of distinct clonal origin presenting with the same resistance mechanism. Overall mortality and death during treatment was high, and despite the high synergism in vitro with vancomycin, death did not differ comparing the use or not of vancomycin plus an active drug against A. baumannii.     

Evidence for a role of glycosphingolipids in CXCR4-dependent cell migration

Chemotaxis induction is a major effect evoked by stimulation of the chemokine receptor CXCR4 with its sole ligand CXCL12. We now report that treatment of CHP-100 human neuroepithelioma cells with the glucosylceramide synthase (GCS) inhibitor DL-threo-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol inhibits CXCR4-dependent chemotaxis. We provide evidence that the phenomenon is not due to unspecific effects of the inhibitor employed and that inhibition of GCS neither affects total or plasmamembrane CXCR4 expression, nor CXCL12-induced Ca(2+) mobilization. The effects of the GCS inhibitor on impairment of CXCL12-induced cell migration temporally correlated with a pronounced downregulation of neutral glycosphingolipids, particularly glucosylceramide, and with a delayed and more moderate downregulation of gangliosides; moreover, exogenously administered glycosphingolipids allowed resumption of CXCR4-dependent chemotaxis. Altogether our results provide evidence, for the first time, for a role glycosphingolipids in sustaining CXCL12-induced cell migration.     

Physicochemical and biological study of selected hydrophobic polyethylenimine-based polycationic liposomes and their complexes with DNA

Non-viral gene therapy is based on the development of efficient and safe gene carrier systems able to transfer DNA into cells. Polyethylenimine (PEI), the most promising non-viral vector, with its high cationic-charge-density potential is able (1) to compact DNA in complexes (polyplexes) smaller than those formed by liposomes (lipoplexes) and (2) to destabilize the endosomal membrane by a 'proton sponge' effect. Several PEI's hydrophobic modifications were reported in the last several years but in some cases a reduced transfection efficiency was observed. The mechanism underlying this phenomenon is not well understood so far. In order to extensively investigate these mechanisms, we reported a physicochemical and biological study of selected hydrophobic PEI's derivatives grafted with chains of different length and percentages of substitution able to form vesicles (polycationic liposomes) and to bind DNA. Their properties were studied by means of dynamic light scattering, freeze-fracture microscopy, potentiometric titrations, gel retardation assays, polyanion exchange reactions, toxicity assays, in vitro transfections, and fluorescence microscopy. Our results indicate that even if polyplexes are able to pass through the cellular membrane, the stability of PEI's hydrophobic polyplexes likely explain their different transfection efficiency in vitro.     

Inotropic activity induced by carbamazepine-alkyne derivative in an isolated heart model and perfused to constant flow

Inotropic activity induced by carbamazepine-alkyne derivative in an isolated heart model and perfused to constant flow Introduction. Few data exist with respect to the effects of carbamazepine and its derivatives at cardiovascular level; furthermore, the molecular mechanisms and cellular site of action are still unclear. Objective. The effects induced by carbamazepine-alquine derivative on perfusion pressure, vascular resistance and left ventricular pressure were evaluated. Materials and methods. The effects of carbamazepine and carbamazepine-alquine on the perfusion pressure, vascular resistance and left ventricular pressure were examined in isolated rat hearts (Langendorff model). Results. Four results were obtained: (1) The carbamazepine-alquine derivative 10-9 mM increased the perfusion pressure and vascular resistance in comparison with the carbamazepine 10-9 mM; (2) the effect of carbamazepine-alquine derivative 10-9-10-4 mM on left ventricular pressure not was inhibited by metoprolol or prazosin at a dose of 10-6 mM; (3) nifedipine 10-6 mM blocked the effects exerted by the carbamazepine-alquine derivative 10-9-10--4 mM on left ventricular pressure, and (4) the carbamazepine-alquine derivative at dose of 10-9 mM increased the concentration of intracellular calcium over a time period of 3-18 min; nevertheless, in presence of nifedipine 10-6 mM this effect was inhibited significantly (p=0.005). Conclusions. The activity exerted by carbamazepine-alquine derivative on perfusion pressure, vascular resistance and left ventricular pressure involved activation of calcium channel type-L, brought indirectly changes in the intracellular calcium levels and subsequently induced a positive inotropic effect.     

Seven days of aerobic exercise training improves conduit artery blood flow following glucose ingestion in patients with type 2 diabetes

The vasodilatory effects of insulin account for up to 40% of insulin-mediated glucose disposal; however, insulin-stimulated vasodilation is impaired in individuals with type 2 diabetes, limiting perfusion and delivery of glucose and insulin to target tissues. To determine whether exercise training improves conduit artery blood flow following glucose ingestion, a stimulus for increasing circulating insulin, we assessed femoral blood flow (FBF; Doppler ultrasound) during an oral glucose tolerance test (OGTT; 75 g glucose) in 11 overweight or obese (body mass index, 34 ± 1 kg/m2), sedentary (peak oxygen consumption, 23 ± 1 ml·kg?1·min?1) individuals (53 ± 2 yr) with non-insulin-dependent type 2 diabetes (HbA1c, 6.63 ± 0.18%) before and after 7 days of supervised treadmill and cycling exercise (60 min/day, 60-75% heart rate reserve). Fasting glucose, insulin, and FBF were not significantly different after 7 days of exercise, nor were glucose or insulin responses to the OGTT. However, estimates of whole body insulin sensitivity (Matsuda insulin sensitivity index) increased (P < 0.05). Before exercise training, FBF did not change significantly during the OGTT (1 ± 7, -7 ± 5, 0 ± 6, and 0 ± 5% of fasting FBF at 75, 90, 105, and 120 min, respectively). In contrast, after exercise training, FBF increased by 33 ± 9, 39 ± 14, 34 ± 7, and 48 ± 18% above fasting levels at 75, 90, 105, and 120 min, respectively (P < 0.05 vs. corresponding preexercise time points). Additionally, postprandial glucose responses to a standardized breakfast meal consumed under "free-living" conditions decreased during the final 3 days of exercise (P < 0.05). In conclusion, 7 days of aerobic exercise training improves conduit artery blood flow during an OGTT in individuals with type 2 diabetes.