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Descubra nuestras soluciones de agua ultrapura Milli-Q® -Tipo I
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  • Nanostructured lipid carriers (NLC) on the basis of Siberian pine (Pinus sibirica) seed oil. 20187575

    Nanostructured lipid carriers (NLC) are new drug systems composed of physiological lipid materials. The possibility of including different types of lipids into the NLC structure revealed the wide prospects for using biologically active natural oils for the development of the cutaneous preparations. In this study the formulation parameters of NLC on the basis of Siberian pine seed oil were evaluated including concentration of lipids, types of surfactants and storage conditions (4 degrees C, 20 degrees C, 40 degrees C). Size distribution and storage stability of formulations produced by hot high pressure homogenisation were investigated by laser diffractometry and photon correlation spectroscopy. The NLC were characterised by their melting behaviour using differential scanning calorimetry. The obtained data indicated the high physical stability of the developed NLC formulations.
    Tipo de documento:
    Referencia
    Referencia del producto:
    20-221
    Nombre del producto:
    NAD Cofactor

  • Pharmacokinetic evaluation of doxorubicin plasma levels in normal and overweight patients with breast cancer and simulation of dose adjustment by different indexes of bod ... 20688160

    Although being used for decades in the treatment of several types of cancer, either alone or in association, only a few data about the pharmacokinetics of doxorubicin (DOX) in humans are available. DOX is frequently used in association with other anticancer drugs in the management of breast cancer. Pharmacokinetic data available in the literature show that after i.v. administration DOX follows a two-compartment open model, with a fast distribution phase followed by a very slow elimination phase. The objective of this work is to perform a pilot study in order to verify if the usual dose adjustment based on body surface area (BSA) would be producing the same plasma concentration-time profiles in patients with normal (<25) and above normal (>25) body mass index (BMI). In order to assess the pharmacokinetics of DOX after a short-term i.v. infusion of 60mg/m(2) of BSA, an experimental design using only five plasma samples of each patient was applied. Samples were collected at 0.00, 0.66 (right after the end of infusion), 1.66, 8.66, and 24.66h. DOX pharmacokinetic profiles were evaluated after quantification of DOX using a new HPLC method developed and validated. Pharmacokinetic parameters (AUC(0-24.66) and C(max)) were analyzed by non-compartmental and compartmental approaches. Significant differences (α=0.05) between overweight and normal weight groups were found with respect to AUC and C(max). After adjustment of dose by weight and by BMI, the compartmental model was used to simulate plasma concentrations and new values for C(max) and AUC(0-24.66) were calculated. The new values obtained using both body weight (BW) and BMI were closer to the normal group than those obtained with BSA. According to the simulation, the differences of AUC and C(max) between the overweight group and the group of patients with normal weight were lower when the dose was adjusted by BW and BMI. These results suggest that more studies must be conducted, with more patients, in order to evaluate the best dose adjustment for DOX in women with breast cancer and overweight.
    Tipo de documento:
    Referencia
    Referencia del producto:
    2752
    Nombre del producto:
    BrdU Cell Proliferation Kit

  • Comparison of Milli-Q PF Plus Water to DEPC-Treated Water in the Preparation and Analysis of RNA 8777061

    The Milli-Q PF Plus water polishing system is equipped with high-purity ion and organic removal media and a capillary fiber ultrafiltration device. The system produces ultrapure water practically free of ribonuclease contamination? The necessity for DEPC treated solutions in RNA molecular biology procedures was tested ny preparing RNA from a variety of tissues and tissue-cultured cells using either DEPC-treated, autoclaved solutions or pure Milli-Q PF water dispensed directly from the system. RNA stability at 37°C was examined for various times using rabbit lung RNA in either DEPC-treated water or Milli-Q PF water. Intact RNA was detected after 6 hours in total RNA and by Northern Blots hybridized with Fibronectin? There was no significant difference in RNA degradation between DEPC-treated water and Milli-Q PF water. We conclude that Milli-Q PF water is an acceptable substitute for DEPC-treated water for the preparation of RNA and Northern Blot analysis.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo

  • Optimisation of ICP-MS collision/reaction cell conditions for the determination of elements likely to be interfered (V, Cr, Fe, Co, Ni, As and Se) in foodstuffs. 21962690

    A strategy for the accurate determination in foodstuffs of seven elements liable to be interfered with (V, Cr, Fe, Co, Ni, As and Se), was successfully applied. Firstly, to reduce spectroscopic interferences, four influential factors (hexapole and quadrupole bias, helium and hydrogen flows) of the collision/reaction cell device were optimised through the experimental design methodology. Secondly, non-spectroscopic interferences, which may severely disturb the analysis of matrices containing large amounts of non-target elements, were significantly reduced by a limited decrease in the flow rate of the optimum initial nebuliser rather than with a specific time-consuming dilution. Finally, the optimised multi-element method was subjected to a full validation that demonstrated its acceptable analytical performance.
    Tipo de documento:
    Referencia
    Referencia del producto:
    03-115
    Nombre del producto:
    RIPAb+ Musashi 2 - RIP Validated Antibody and Primer Set, rabbit monoclonal

  • Potentiation of GABAA-mediated synaptic current by ethanol in hippocampal CA1 neurons: possible role of protein kinase C. 8138953

    Ethanol has been reported to interact with numerous voltage- and ligand-gated ion channels in central mammalian neurons. In particular, the type A gamma-aminobutyric acid (GABAA) receptor/chloride ionophore complex has received considerable attention as a cellular substrate for ethanol and other sedative-hypnotic drugs. Direct electrophysiological evidence that ethanol modulates GABAA receptor function has been controversial. In this study, we investigated the effects of ethanol on the GABAA receptors that mediate fast inhibitory synaptic transmission in the rat hippocampus. Using the whole-cell patch-clamp recording technique in brain slices, we found that clinically relevant concentrations of ethanol (10-50 mM) potentiate pharmacologically isolated GABAA-mediated inhibitory postsynaptic currents (IPSCs) recorded from rat hippocampal CA1 neurons. In addition, we demonstrate that ethanol- but not diazepam-mediated enhancement of GABAA IPSCs requires intracellular ATP and can be blocked by Ro-31-8220 or PKC19-31, specific inhibitors of protein kinase C. Furthermore, the active phorbol ester 4-beta-PDBu but not its inactive analog also interferes with ethanol enhancement of GABAA IPSCs. These results demonstrate that ethanol potentiation of pharmacologically isolated GABAA IPSCs can be modulated by protein kinase C.
    Tipo de documento:
    Referencia
    Referencia del producto:
    20-176
    Nombre del producto:
    100X GTPγS, 10mM

  • A novel post-translational modification in nerve terminals: O-linked N-acetylglucosamine phosphorylation. 21500857

    Protein phosphorylation and glycosylation are the most common post-translational modifications observed in biology, frequently on the same protein. Assembly protein AP180 is a synapse-specific phosphoprotein and O-linked beta-N-acetylglucosamine (O-GlcNAc) modified glycoprotein. AP180 is involved in the assembly of clathrin coated vesicles in synaptic vesicle endocytosis. Unlike other types of O-glycosylation, O-GlcNAc is nucleocytoplasmic and reversible. It was thought to be a terminal modification, that is, the O-GlcNAc was not found to be additionally modified in any way. We now show that AP180 purified from rat brain contains a phosphorylated O-GlcNAc (O-GlcNAc-P) within a highly conserved sequence. O-GlcNAc or O-GlcNAc-P, but not phosphorylation alone, was found at Thr-310. Analysis of synthetic GlcNAc-6-P produced identical fragmentation products to GlcNAc-P from AP180. Direct O-linkage of GlcNAc-P to a Thr residue was confirmed by electron transfer dissociation MS. A second AP180 tryptic peptide was also glycosyl phosphorylated, but the site of modification was not assigned. Sequence similarities suggest there may be a common motif within AP180 involving glycosyl phosphorylation and dual flanking phosphorylation sites within 4 amino acid residues. This novel type of protein glycosyl phosphorylation adds a new signaling mechanism to the regulation of neurotransmission and more complexity to the study of O-GlcNAc modification.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AP180
    Nombre del producto:
    Donkey Anti-Goat IgG Antibody, Species Adsorbed

  • LC method for telithromycin in tablets: a stability-indicating assay. 18977423

    A liquid chromatographic (LC) method for the quantitative determination of telithromycin, the first member of the ketolides, which is a new class of macrolides, was developed. Analytical parameters were studied according to International Conference on Harmonization (ICH) guidelines. An Ace RP-18 octadecyl silane column (250 mm x 4.6 mm, 5 microm) maintained at 50 degrees C was used as the stationary phase, and methanol and 0.067 M potassium monobasic phosphate buffer pH 4.0 (55:45, v/v) were used as the mobile phase with UV detection at 265 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature were investigated showing no interference in the drug peak. The method was linear (r=0.9999) at concentration ranging from 10.0 to 40.0 microg/mL, precise (intra-day relative standard deviation [RSD] and inter-day RSD values<2.0%), accurate (mean recovery=100.76%), specific and robust. Detection and quantitation limits were 0.0027 and 0.0082 microg/mL, respectively. The results showed the proposed method is suitable for its intended use. The validated method may be used to quantify telithromycin tablets and to determine the stability of the drug. The method is able to separate telithromycin from its degradation products and tablet excipients for its sensitivity and reproducibility. These results are in accordance with a previous microbiological assay study, which used the same tested conditions showing that the methods can be interchangeable.,
    Tipo de documento:
    Referencia
    Referencia del producto:
    2752
    Nombre del producto:
    BrdU Cell Proliferation Kit

  • Extraction of extracellular polymeric substances from extreme acidic microbial biofilms 18330567

    The efficiency of five extraction methods for extracellular polymeric substances (EPS) was compared on three benthic eukaryotic biofilms isolated from an extreme acidic river, Río Tinto (SW, Spain). Three chemical methods (MilliQ water, NaCl, and ethylenediamine tetraacetic acid [EDTA]) and two physical methods (Dowex 50.8 and Crown Ether cation exchange resins) were tested. The quality and quantity of the EPS extracted from acidic biofilms varied according to which EPS extraction protocol was used. Higher amounts were obtained when NaCl and Crown Ether resins were used as extractant agents, followed by EDTA, Dowex, and MilliQ. EPS amounts varied from approximately 155 to 478 mg g-1 of dry weight depending on the extraction method and biofilm analyzed. EPS were primarily composed of carbohydrate, heavy metals, and humic acid, plus small quantities of proteins and DNA. Neutral hexose concentrations corresponded to more than 90% of the total EPS dry weight. The proportions of each metals in the EPS extracted with EDTA are similar to the proportions present in the water from each locality where the biofilms were collected except for Al, Cu, Zn, and Pb. In this study, the extracellular matrix heavy metal sorption efficiencies of five methods for extracting EPS from eukaryotic acidic biofilms were compared.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo

  • Determining estrogenic steroids in Taipei waters and removal in drinking water treatment using high-flow solid-phase extraction and liquid chromatography/tandem mass spec ... 17428520

    River water and wastewater treatment plant (WWTP) effluents from metropolitan Taipei, Taiwan were tested for the presence of the pollutants estrone (E1), estriol (E3), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) using a new methodology that involves high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry. The method was also used to investigate the removal of the analytes by conventional drinking water treatment processes. Without adjusting the pH, we extracted 1-L samples with PolarPlus C18 Speedisks under a flow rate exceeding 100 mL/min, in which six samples could be done simultaneously using an extraction station. The adsorbent was washed with 40% methanol/60% water and then eluted by 50% methanol/50% dichloromethane. The eluate was concentrated until almost dry and was reconstituted by 20 μL of methanol. Quantitation was done by LC-MS/MS-negative electrospray ionization in the selected reaction monitoring mode with isotope-dilution techniques. The mobile phase was 10 mM N-methylmorpholine aqueous solution/acetonitrile with gradient elution. Mean recoveries of spiked Milli-Q water were 65–79% and precisions were within 2–20% of the tested concentrations (5.0–200 ng/L). The method was validated with spiked upstream river water; precisions were most within 10% of the tested concentrations (10–100 ng/L) with most RSDs < 10%. LODs of the environmental matrixes were 0.78–7.65 ng/L. A pre-filtration step before solid-phase extraction may significantly influence the measurement of E1 and EE2 concentrations; disk overloading by water matrix may also impact analyte recoveries along with ion suppression. In the Taipei water study, the four steroid estrogens were detected in river samples (ca. 15 ng/L for E2 and EE2 and 35−45 ng/L for E1 and E3). Average levels of 19–26 ng/L for E1, E2, and EE2 were detected in most wastewater effluents, while only a single effluent sample contained E3. The higher level in the river was likely caused by the discharge of untreated human and farming waste into the water. In the drinking water treatment simulations, coagulation removed 20–50% of the estrogens. An increased dose of aluminum sulfate did not improve the performance. Despite the reactive phenolic moiety in the analytes, the steroids were decreased only 20–44% of the initial concentrations in pre- or post-chlorination. Rapid filtration, with crushed anthracite playing a major role, took out more than 84% of the estrogens. Except for E3, the whole procedure successfully removed most of the estrogens even if the initial concentration reached levels as high as 500 ng/L.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
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