Functional Quality (functional + quality)

Distribution by Scientific Domains

Selected Abstracts

Performance characteristics according to Commission Decision 2002/657/EC in the fluorimetric determination of tetracycline in the absence and in the presence of magnesium

Noelia Rodríguez
Abstract The fluorimetric determination of tetracycline is usually carried out in the presence of some metals that, through the formation of a complex with this antibiotic, enhance its fluorescence emission, giving more sensitive determination methods. It is well established that magnesium is one of these metals. However, it is possible that higher signals do not mean a real improvement in the quality of the analytical method. In this work, the univariate and multivariate fluorescence determination of tetracycline is performed in the presence and absence of Mg2+, comparing the quality of the analyses through some performance characteristics that, according to Commission Decision 2002/657/EC define the functional qualities of analytical methods. The methods with the best performance characteristics were multivariate determinations carried out in the absence of Mg2+, both when emission or excitation spectra were taken, the decision limits (CC,) being 13.1 and 20.1 µg/L and the detection capabilities (CC,) 25.3 and 38.5 µg/L, respectively. This study points out through a case study that higher analytical signals do not necessarily mean better performance characteristics of a method of analysis. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Glycosaminoglycans and the peritoneaum

NEPHROLOGY, Issue 5 2002
Susan YUNG
SUMMARY: The introduction of peritoneal dialysis (PD) over two decades ago has allowed us to manipulate the peritoneal membrane to perform as a continuous dialysing organ. to maximize the efficacy of solute transport and waste removal, conventional PD fluids require unphysiological concentrations of glucose to provide the osmotic drive, lactate to alleviate metabolic acidosis, and a low pH to prevent the caramelization of glucose during the preparation of the solutions. These factors either alone or in combination, are irritants to the peritoneal membrane. Thus, continuous exposure of the peritoneum to PD solutions, together with frequent episodes of peritonitis confers a chronic inflammatory response within the peritoneum. It is, therefore, not unexpected that with time, long-term PD patients develop structural and functional changes within the peritoneum, which in many cases develop into peritoneal fibrosis of varying degrees and compromises the peritoneal membrane as a dialysing organ. to date, numerous studies have investigated methods to improve the efficiency of PD and preserve the structure of the peritoneal membrane. Recently, a number of reports have documented the beneficial effects of intraperitoneal administration of glycosaminoglycans (GAGs) on both the structural and functional qualities of the peritoneum. In this context, GAGs have been demonstrated to inhibit collagen synthesis within the peritoneum, decrease peritoneal advanced glycosylated end-products (AGE) deposition, and modulate cytokine and growth factor synthesis. This review will examine the available data with regards to the potential role of GAGs in maintaining ultrafiltration, solute transport and the structural integrity of the peritoneum. [source]

Colon interposition in the treatment of esophageal caustic strictures: 40 years of experience

J. Đ. Knez
SUMMARY., The objective of this article was to analyze 40 years of experience of colon interposition in the surgical treatment of caustic esophageal strictures from the standpoints of our long-term personal experience. Colon interposition has proved to be the most suitable type of reconstruction for esophageal corrosive strictures. The choice of colon graft is based on the pattern of blood supply, while the type of anastomosis is determined by the stricture level and the part of colon used for reconstruction. In the period between 1964 and 2004, colon interposition was performed in 336 patients with a corrosively scared esophagus, using the left colon in 76.78% of the patients. In 87.5% a colon interposition was performed, while in the remaining patients an additional esophagectomy with colon interposition had to be done. Hypopharyngeal strictures were present in 24.10% of the patients. Long-term follow-up results were obtained in the period between 1 to up to 30 years. Early postoperative complications occurred in 26.48% of patients, among which anastomosic leakage was the most common. The operative mortality rate was 4.16% and late postoperative complications were present in 13.99% of the patients. A long-term follow up obtained in 84.82% of the patients found excellent functional results in 75.89% of them. We conclude that a colon graft is an excellent esophageal substitute for patients with esophageal corrosive strictures, and when used by experienced surgical teams it provides a low rate of postoperative morbidity and mortality, and long-term good and functional quality of life. [source]

Functional consequences of cartilage degeneration in the equine metacarpophalangeal joint: quantitative assessment of cartilage stiffness

Summary Reasons for performing study: No quantitative data currently exist on the relationship of the occurrence of cartilage degeneration and changes in site-specific biomechanical properties in the metacarpophalangeal (MCP) joint in the horse. Objectives: To gain insight into the biomechanical consequences of cartilage deterioration at 2 differently loaded sites on the proximal articular surface of the proximal phalanx (P1). Hypothesis: Static and dynamic stiffness of articular cartilage decreases significantly in degenerated cartilage. Methods: Cartilage degeneration index (CDI) values were measured at the lateral dorsal margin (Site 1), lateral central fovea (Site 2) and entire joint surface of P1 (CDIP1) in 30 horses. Group 1 contained joints without (CDIP1 values <25%, n = 22) and Group 2 joints with (CDIP1 values >25%, n = 8) signs of cartilage degeneration. Cartilage thickness at Sites 1 and 2 was measured using ultrasonic and needle-probe techniques. Osteochondral plugs were drilled out from Sites 1 and 2 and subsequently tested biomechanically in indentation geometry. Young's modulus at equilibrium and dynamic modulus were determined. Results: Cartilage thickness values were not significantly different between the 2 groups and sites. Young's modulus at Site 1 was significantly higher in Group 1 than in Group 2; at Site 2, the difference was not significant. Dynamic modulus values were significantly higher in Group 1 than in Group 2 at both sites. Conclusions: Degenerative cartilage changes are clearly related to loss of stiffness of the tissue. Absolute changes in cartilage integrity in terms of CDI are greatest at the joint margin, but concomitant changes are also present at the centre, with a comparable decrease of the biomechanical moduli at the 2 sites. Therefore, significant cartilage degradation at the joint margin not only reflects local deterioration of biomechanical properties, but is also indicative of the functional quality in the centre. Potential relevance: These findings may be important for improving prognostication and developing preventative measures. [source]

Decreased protein tyrosine phosphorylation and membrane fluidity in spermatozoa from infertile men with varicocele

M.G. Buffone
Abstract Varicocele is a prevalent pathology among infertile men. The mechanisms linking this condition to infertility, however, are poorly understood. Our previous work showed a relationship between sperm functional quality and the ability of spermatozoa to respond to capacitating conditions with increased membrane fluidity and protein tyrosine phosphorylation. Given the reported association between varicocele, oxidative stress, and sperm dysfunction, we hypothesized that spermatozoa from infertile patients with varicocele might have a combined defect at the level of membrane fluidity and protein tyrosine phosphorylation. Semen samples from infertile patients with and without grade II/III left varicocele were evaluated for motion parameters (computer-assisted semen analysis [CASA]), hyperactivation (CASA), incidence and intensity of protein tyrosine phosphorylation (phosphotyrosine immunofluorescence and western blotting), and membrane fluidity (Laurdan fluorometry), before and after a capacitating incubation (6 hr at 37°C in Ham's F10/BSA, 5% CO2). Spermatozoa from varicocele samples presented a decreased response to the capacitating challenge, showing significantly lower motility, hyperactivation, incidence and intensity of tyrosine phosphorylation, and membrane fluidity. The findings reported in this article indicate that the sperm dysfunction associated to infertile varicocele coexists with decreased sperm plasma membrane fluidity and tyrosine phosphorylation. These deficiencies represent potential new pathophysiological mechanisms underlying varicocele-related infertility. Mol. Reprod. Dev. 73: 1591,1599, 2006. © 2006 Wiley-Liss, Inc. [source]

Decreased polyunsaturated and increased saturated fatty acid concentration in spermatozoa from asthenozoospermic males as compared with normozoospermic males

ANDROLOGIA, Issue 5 2006
H. Tavilani
Summary The lipid composition of the sperm membrane has been shown to exert a significant effect upon the functional quality of spermatozoa. We have studied fatty acid composition of the phospholipids in spermatozoa in asthenozoospermic and normozoospermic men and determined the ratio of polyunsaturated fatty acids (PUFAs) to saturated fatty acids of spermatozoa of these two groups. Fatty acid concentration of spermatozoa was determined in 15 asthenozoospermic and eight normozoospermic semen samples by thin layer chromatography and gas chromatography. The most abundant polyunsaturated and saturated fatty acids in normozoospermic samples were docosahexaenoic acid (DHA 22 : 6 ,3, 98.5 ± 4.5 nmol per 108 spermatozoa, mean ± SE) and palmitic acid (103 ± 17 nmol per 108 spermatozoa) respectively. The mean ± SE values of DHA and palmitic acid in asthenozoospermic samples were 53.9 ± 11.6 and 145 ± 14.7 nmol per 108 spermatozoa respectively. Compared with normozoospermic samples, asthenozoospermic samples showed lower levels of PUFA and higher amount of saturated fatty acids. The mean ± SE ratios of sperm PUFA/saturated fatty acids in asthenozoospermic and normozoospermic samples were 0.66 ± 0.06 and 1.45 ± 0.16 (P < 0.001) respectively. This study demonstrates that spermatozoa of asthenozoospermic men have lower levels of PUFA compared with saturated fatty acids. This may be contributory to the poor motility noted in samples from these men. [source]

Protein and the demand for hard wheats,

William W. Wilson
Wheat protein is one of the most important specifications used in domestic and import purchase contracts and is used partly as a proxy for functional quality. The purpose of this article is to analyse the demand for wheat delineated by protein class. A choice-based econometric model is specified and estimated using a novel dataset of pooled wheat shipments to individual importing countries. Buyers are importing countries that make purchase decisions among different protein levels. The model frames the choice in terms of attributes of the choice and of the importing countries. Results indicate that there have been shifts over time, and purchase probabilities are highly price elastic and vary across importing regions. Functional characteristics including wet gluten content and extraction rates have significant impacts on purchase probabilities. These results have implications for breeders as it clearly illustrates the role of protein and functional characteristics on demand. The results also have implications for analysts modelling wheat trade in that there are many factors impacting market segments that would not be captured in conventional demand specifications. [source]