Search results for " concentration"
showing 10 items of 1684 documents
Mutation of the important Tyr-33 residue of chicken avidin: functional and structural consequences
2002
The strong interaction between avidin and biotin is so tight (dissociation constant 10-15M) that conditions usually sufficient for protein denaturing fail to dislodge biotin from the avidin—biotin complex. This kind of irreversible binding hinders the use of avidin in applications such as affinity purification or protein immobilization. To address this concern, we have constructed a series of mutants of the strategically positioned Tyr-33 in order to study the role of this residue in biotin binding, and to create avidin variants with more reversible ligand-binding properties. Unexpectedly, an avidin mutant in which Tyr-33 was replaced with phenylalanine (Avm-Y33F) displayed similar biotin-b…
Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Bisoprolol Fumarate
2014
Abstract Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate-release (IR) solid oral dosage forms containing bisoprolol as the sole active pharmaceutical ingredient (API) are reviewed. Bisoprolol is classified as a Class I API according to the current Biopharmaceutics Classification System (BCS). In addition to the BCS class, its therapeutic index, pharmacokinetic properties, data related to the possibility of excipient interactions, and reported BE/bioavailability problems are taken into consideration. Qualitative compositions of IR tablet dosage forms of bisoprolol with a marketing authorization (MA) in ICH (Inter…
Bisphenol A removal from water by biomass-based carbon: isotherms, kinetics and thermodynamics studies
2018
Biomass-based carbon was modified and used as an efficient bisphenol A (BPA) sorbent. The simple and environmentally friendly modification method produced sorbent with a capacity of 41.5 mg/g. The ...
Functionally active complement proteins C6 and C7 detected in C6- and C7-deficient individuals
1991
SUMMARYTwo sensitive sandwich ELISAs based on monoclonal antibodies directed to native C6 and C7 allowed the detection and quantitation of these complement proteins in 20 out of 37 serum samples from individuals who had previously been classified as deficient in these proteins as assessed by immunochemical and/or functional assays. Furthermore, serum from four C6-deficient and one combined C6-/C7-deficient individual showed an increase in the terminal complement complex (TCC) and a decrease in native C6 and C7 after complement activation as assayed by specific ELISAs. Despite their (incomplete) deficiencies, these individuals therefore possess functionally active terminal complement protein…
Physiological and agonistic behavioural response of Procambarus clarkii to an acoustic stimulus
2012
Summary This study examined the effects of an acoustic stimulus on the haemolymph and agonistic behaviour of the red swamp crayfish Procambarus clarkii. The experiment was conducted in a tank equipped with a video recording system using 6 groups (3 control and 3 test groups) of five adult crayfish (30 specimens in total). After one hour of habituation, the behaviour of the crayfish was monitored for two hours. During the second hour, the animals in the test groups were exposed to a linear sweep (frequency range 0.1-25 kHz; peak amplitude 148 dBrms re 1 µPa at 12 kHz) acoustic stimulus for 30 minutes. Exposure to the noise produced significant variations in haemato-immunological parameters a…
Microregional distributions of glucose, lactate, ATP and tissue pH in experimental tumours upon local hyperthermia and/or hyperglycaemia
1993
Microregional distributions of glucose, lactate and ATP concentrations as well as tissue pH values were determined in subcutaneous rat tumours during normothermia and normoglycaemia, and upon local hyperthermia (HT) and/or hyperglycaemia (HG). Experiments were performed in order to investigate whether, and to what extent, these adjuvant therapeutic measures applied alone or in combination can modify the bioenergetic and metabolic status, parameters that are known to markedly influence the therapeutic response of tumours to heat. Local HT was performed in a saline bath (44 degrees C/2 h) and HG was induced by i.v. infusion of glucose for 2.5 h (blood glucose levels during heating: 35-40 mM).…
Acute changes of systemic parameters in tumour-bearing rats, and of tumour glucose, lactate, and ATP levels upon local hyperthermia and/or hyperglyca…
1991
Arterial blood pressure and relevant parameters of the arterial blood (O2 and CO2 tensions, pH, haematocrit, serum electrolytes and osmolality) were determined in tumour-bearing rats upon local hyperthermia (HT) and/or hyperglycaemia (HG). Tumour heating was performed in a saline bath (44 degrees C) for 120 min; hyperglycaemia was induced by i.v. infusion of 40% glucose solution for 150 min [blood glucose levels: 35-40 mM during heating; total amount of glucose: 1.19 g/100 g body wt.; infusion rates: 0.31 ml (100 g body wt.)-1 min-1 for 2 min, 0.02 ml (100 g body wt.)-1 min-1 for 88 min, and 0.01 ml (100 g body wt.)-1 min-1 for 60 min]. Immediately after treatment, glucose, lactate and ATP …
Properties of erythrocyte light refraction in diabetic patients.
2001
Since hyperglycaemia changes the erythrocyte cell membrane fluidity and impairs cell deformity, our goal was to characterize hemoglobin and red blood cell (RBC) light refractive property changes in diabetic patients. Microscopic investigation was carried out on intact and fixed RBCs. To determine the refractive index (RI): smears of peripheral blood were air dried and fixed for 3 min in methanol. Mixtures of polyvinylpyrolidine and buffer of different pH (1:1) were used as embedding media. Intact RBCs were mixed with a buffered embedding medium, placed on a slide and overlaid with a coverslip. Interference microscopy was used for RI measurements at 18 different pH (pH=2-13). The results sho…
A new approach for selection of Oenococcus oeni strains in order to produce malolactic starters.
2005
The lactic acid bacterium Oenococcus oeni, mainly responsible for malolactic fermentation (MLF), is used in new winery process as starter culture for direct inoculation. The difficulty to master MLF according to the wine led us to search a new approach to select effective O. oeni strains. Biochemical and molecular tests were performed in order to characterize three strains of O. oeni selected for malolactic starter elaboration. Malolactic and ATPase activities that appeared as a great interest in MLF were measured and the expression of a small heat shock protein Lo18 was evaluated by immunoblotting and real-time PCR. These results were correlated with the performances of strains in two red …
Tucupentol, a novel mono-tetrahydrofuranic acetogenin from Annona montana, as a potent inhibitor of mitochondrial complex I.
2009
Ten acetogenins, one of them new, were isolated from leaves and twigs of a Bolivian collection of Annona montana. The new compound that we named tucupentol (1) is a mono-tetrahydrofuranpentahydroxy-acetogenin. The inhibitory potency of tucupentol (1) on the mitochondrial complex I was evaluated, and this activity was compared with that of the known acetogenins, annonacin-A, cisannonacin-10-one, aromin, and gigantetronenin, also isolated from this plant material. The mentioned acetogenins acted as selective inhibitors of mitochondrial complex I in the 0.8-5.4-nM range. Fil: Álvarez Colom, Olga. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química …