Search

Purpose: The study aimed to determine the influence of drug treatments (proton pump inhibitors [PPIs] combined with other drugs) on the false-positive (FP) rate in the fecal immunochemical test (FIT). Methods: Patients undergoing colonoscopy in the setting of a CRC screening program due to a positive FIT result were included prospectively. Demographic data and drug intake of PPIs, antiplatelet therapy (APA), anticoagulants, selective serotonin reuptake inhibitors (SSRIs), and nonsteroidal anti-inflammatory drugs (NSAIDs) were collected. An FP FIT result was considered normal colonoscopy or with nonneoplastic pathology (NNP). Logistic regression models were used to evaluate the effect of these drugs on the rate of FP FIT results. Results: We included 515 patients, and 59% (304/515) were males. The rate of FP FIT results was 48% (249/515). Study drug use was higher in patients > 60 years old and females than in those < 60 years old and males (p < 0.001 and p = 0.049, respectively). Multivariate logistic regression revealed that female sex (OR = 2.7 95% CI 1.9–3.9), NNP (OR = 1.5 95% CI 1.1–2.2), and the use of any of the study drugs (OR = 1.4 95% CI 0.9–2.0) were independent risk factors for FP FIT results. The risk of FP FIT results was significantly higher in PPI users than in nonusers (OR = 1.8 95% CI 1.1–2.9), specifically when PPIs were combined with other drugs (OR = 2.01 95% CI 1.1–3.6) only in men. Conclusion: Female sex, NNP, and PPIs combined with other drugs in males were identified as independent risk factors for FP FIT results. [ABSTRACT FROM AUTHOR]

The removal of heavy metals from wastewater by using activated alumina or chitosan as adsorbers was evaluated. Cd(II) and Cr(III) were employed as models of the behaviour of divalent and trivalent metal ions. The adsorption of Cd(II) and Cr(III) onto the adsorbers evaluated was studied as a function of pH, time, amount of adsorber, concentration of metal ions and sample volume. A 0.4-g portion of activated alumina can retain 0.6 mg Cr(III) and 0.2 mg Cd(II) from 20 mL sample adjusted at pH 4 and stirred for 30 min. It is therefore possible to totally decontaminate 500 mL of a waste containing 5 mg L-1 Cd(II) and Cr(III) with 10 g alumina. On the other hand, 0.4 g chitosan can totally decontaminate 20 mL of a pH 5 solution containing up to 50 mg L-1 Cd(II) and Cr(III). A 99.2±0.1% retention of Cd(II) and 83±1% retention of Cr(III) was obtained from 500 mL of a laboratory waste. The aforementioned strategies were applied for the minimization of analytical chemistry teaching laboratories and atomic spectrometry laboratory wastes. On comparing both adsorbers it can be concluded that chitosan is more preferable than alumina due to the reduced price of chitosan and the absence of side-pollution effects. [ABSTRACT FROM AUTHOR]

The radical polymerization of methyl n-octadecyl itaconate initiated with AIBN, produces poly(methyl n-octadecyl itaconate) with a yield of 47% and a molecular weight of about 105 g/mol. 13C-NMR studies point out that this polymer is mainly syndiotactic. The combined studies of DSC and solid state 13C CP/MAS NMR indicate that the polymer side chains are able to crystallize in a paraffinic phase, presumably in an hexagonal form which melts at 44°C with a ΔH of 4.8Kcal/mol. [ABSTRACT FROM AUTHOR]

A new technique to thermally fractionate polymers using DSC has been recently developed in our laboratory. The applications of the novel successive self-nucleation and annealing (SSA) technique to characterize polyolefins with very dissimilar molecular structures are presented as well as the optimum conditions to thermally fractionate any suitable polymer sample with SSA. For ethylene/α-olefin copolymers, the SSA technique can give information on the distribution of short chain branching and lamellar thickness. In the case of functionalized polyolefins, detailed examinations of SSA results can help to establish possible insertion sites of grafted molecules. The application of the technique to characterize crosslinked polyethylene and crystallizable blocks within ABC triblock copolymers is also presented. [ABSTRACT FROM AUTHOR]

A correction to this paper has been published: https://doi.org/10.1007/s00384-021-03947-1 [ABSTRACT FROM AUTHOR]

To assess the role of leucine as a precursor of alanine α-amino nitrogen in skeletal muscle during diabetes, extensor digitorum longus muscles from control ( n = 7 experiments) and streptozotocin-diabetic rats ( n = 8 experiments) were isolated and superfused with [15N]leucine (3 mmol/l) in the presence of glucose (10 mmol/l) for 2 h. Muscle perchloric acid extraction was performed at the end of superfusion in order to quantify newly synthesized alanine by 15N/1H nuclear magnetic resonance. Release of [15N]alanine in the superfusion medium was also measured. The pool of newly synthesized [15N]alanine was significantly increased ( ∼ 40 %) in extensor digitorum longus muscles from streptozotocin-diabetic rats. Whereas a significant enhancement of total alanine release from muscle was induced by diabetes (20 %), only a slight increase in [15N]alanine release was detectable under our experimental conditions. Consequently, we conclude that streptozotocin-diabetes in growing rats induces in skeletal muscle: 1) an increase in nitrogen exchange between leucine and alanine leading to newly synthesized [15N]alanine; and 2) an increase of total alanine release from muscle originating from both proteolysis and de novo synthesis. [Diabetologia (1997) 40: 1159–1165] [ABSTRACT FROM AUTHOR]

The influence of starvation on protein synthesis in the adult rat brain was studied in vivo by an intravenous injection of a flooding dose of unlabeled valine including a tracer dose of L-[3,4(n)-H]valine. Brief starvation (24 hours) induced a 20% decline in fractional and absolute rates of brain protein synthesis. This decline resulted from a 20% decrease in the efficiency of protein synthesis (μg protein synthesized per day per μg RNA) whereas the capacity for protein synthesis (μg RNA per mg protein) was maintained. Prolonged starvation (5 days) was marked by no further significant changes in the fractional rate, absolute rate and efficiency of protein synthesis, whereas the capacity for protein synthesis cecreased slightly. The relative contribution of brain to wholebody body protein synthesis increased during fasting, and neither the protein nor the RNA brain content did change during the experiment. These results clearly indicate that brain proteins are spared in response to brief and prolonged food deprivation, and that brain protein synthesis is very sensitive to short-term fasting. [ABSTRACT FROM AUTHOR]

A new procedure to fractionate ethylene/α-olefin copolymers using DSC is presented. This procedure allows melt/melt and melt/solid segregation to occur during thermal cycles that promote self-nucleation, crystallization and annealing processes ( Successive Self-Nucleation/ Annealing, SSA). The SSA has been compared with the Step-Crystallization (SC) method proposed earlier in the literature to qualitatively characterize chain branching distribution in a faster and easier way than Temperature Rising Elution Fractionation ( TREF). In general, SSA produces better fractionation than SC and the DSC derived chain branching distribution by SSA can be qualitatively comparable to that obtained by TREF. The SSA technique could have important applications for the characterization of polymers that crystallize over a broad temperature range. [ABSTRACT FROM AUTHOR]

Graft copolymers of atactic polypropylene (aPP) and polystyrene (PS) were synthesized and characterized by C NMR analysis. The C NMR spectra of the grafts exhibited changes with respect to physical blends of identical compositions. The most important occurred in the meso sequences of the aPP blocks of the copolymer. These changes suggest that some grafting took place during the synthesis. SEM micrographs indicate greater interfacial interaction between phases in the copolymers than in the physical blends. Thermal Analysis showed that the Tg of the copolymers is higher than that of the PS homopolymers prepared under the same conditions. This could be the result of an apparent increased in molecular weight caused by the grafting of the aPS into the aPP chains. TGA results indicated that the thermal stability of the copolymer decreases as the aPP content in the copolymer increases. [ABSTRACT FROM AUTHOR]

Differential Scanning Calorimetry (DSC) can provide a qualitative measure of the state of dispersion of an immiscible blend if the minor phase exhibits fractionated crystallization when dispersed into fine particles. The technique is only sensitive to the volume of the dispersed particle and not to its shape and can only be used when the exotherms of interest do not overlap with other thermal transitions present in the multicomponent system. Selfnucleation is a valuable tool to ascertain the presence of fractionated crystallization. The morphology induced by fractionated crystallization in immiscible blends could lead to enhanced plastic deformation during yielding of the matrix. [ABSTRACT FROM AUTHOR]

These studies were undertaken to investigate the influence of the precursor amino acid on the measurement of whole-body protein turnover by the flooding-dose method. Whole-body protein synthesis rates were estimated in 70 g rats using an intravenous injection of L-(UC) Threonine, L-(UC) Lysine (200 µmoles/100g; 0.15 µCi/ µmol or 1000 µmoles/100 g; 0.15 µCi/ µmol), L-(UC) Phenylalanine, L-(1C) Leucine or L-(UC) Histidine (200 µmoles/100 g; 0.15 µCi/ µmol). Forty two rats were divided into seven groups. Each group received a large dose of one of the labelled amino acids. In each group, one animal was killed every 2 min between 5 and 15 min after the injection. Whole-body protein fractional rate was determined from the slope of the linear regression of Sb( t) (protein specific radioactivity) against Si′( t) × t, where Si′( t) is the average specific radioactivity of free tissue amino acids between 0 and t. Whole-body protein fractional synthesis rates were 41.4, 25.6, 31.1, 31.4 and 22.8%/day with threonine, lysine, phenylalanine, leucine and histidine respectively. These data suggest that the estimation of whole-body protein synthesis rate varies according to the amino acid used because of the heterogeneity of the protein pool. [ABSTRACT FROM AUTHOR]