Development of an ELISA for pantothenic acid (vitamin B5) for application in the nutrition and biological fields

Immunological assays appear to be the only alternative to the microbiological method for analysis of pantothenic acid in foods and blood. In order to evaluate the influence of the linker on the immunogenicity of the hapten, we have tried to raise antisera against pantothenic acid in rabbits using different conjugates. The hapten was coupled to a carrier protein (BSA or thyroglobulin) using adipoyl dichloride (adipoyl conjugate) or bromoacetyl bromide (acetyl conjugate). Only the acetyl conjugate has induced the production of a specific antibody. With this antibody, an assay on microplate using the ELISA inhibition technique was developed to measure pantothenic acid. The use of pantothenic acid coupled to thyroglobulin with adipoyl dichloride as the capture antigen has improved the sensitivity of the ELISA. This assay was applied to food products and blood.     

Cigarette smoking as a determinant of high-grade carotid artery stenosis in Hispanic, black, and white patients with stroke or transient ischemic attack

The effect of chitin, poly-beta-(1 --> 4)-N-acetyl-glucosamine, and chitosan, a polymer of glucosamine obtained by the deacetylation of chitin, on growth and nutrient digestibility was studied in grass shrimp, Penaeus monodon. Shrimp were fed for 8 wk diets containing no supplement (control) or 2, 5 or 10 g/100 g chitin or chitosan. Each diet was fed to triplicate groups of shrimp with a mean initial body weight of 0.45 +/- 0.05 g. Significantly higher body weight gains were observed in shrimp fed the 5% chitin diet than in those fed the 10% chitin or the control diet. The weight gain of shrimp decreased as dietary chitosan supplementation level increased (r = 0. 87, P < 0.05). Feed efficiencies (FE) and protein efficiency ratios (PER) followed the same pattern. Lower protein and lipid digestibilities and lower body protein and lipid contents were observed in shrimp fed all chitosan-containing diets than in controls (P < 0.05). Carbohydrate digestibility was lower in shrimp fed the 10% chitosan diet than in those fed the control diet. Lower protein and lipid digestibilities, body lipid content and blood cholesterol concentration were observed in shrimp fed the 10% chitin diet compared with controls (P < 0.05). Higher weight gains, body lipid contents and blood cholesterol concentrations were observed in shrimp fed the 2 and 5% chitin diets than in those fed the chitosan diets. Shrimp fed the 5% chitin diet had higher protein and lipid digestibilities and higher body protein content than those fed the 5% chitosan diet (P < 0.05). These data suggest that dietary chitin, supplemented at 5%, enhances P. monodon growth, whereas chitosan depresses shrimp growth, regardless of the supplementation level.     

Apoptosis, reproductive failure, and oxidative stress in Chinese hamster ovary cells with compromised genomic integrity

Chromosomal instability and persistent reproductive cell death show a significant correlation after cells are exposed to ionizing radiation. To examine the possible role of apoptosis in persistent reproductive cell death, we analyzed subsets of chromosomally stable and unstable clones for relationships between chromosome stability, reproductive integrity, and apoptosis. All clones were generated from the GM10115 cell line and derived from single progenitor cells surviving 10 Gy of X-rays, and all measurements were made approximately 60-80 generations after irradiation. The incidence of apoptosis, as measured by both annexin V binding of phosphatidylserine residues and terminal deoxynucleotidyl transferase labeling of DNA strand breaks, was significantly higher in chromosomally unstable clones than it was in chromosomally stable clones (P < 0.05; ANOVA and Student's t test). Furthermore, statistical analyses of the biological end points of persistent reproductive cell death and apoptosis were consistent, showing R2 values of 0.78 and 0.76, respectively. These results suggest that persistent reproductive cell death can, in part, be explained by the predisposition of a fraction of the clonal population to undergo apoptosis or necrosis. Immunological blot analyses of protein levels and DNA bandshift assays confirmed the mutant status of p53 in the host cell line, implying an apoptotic pathway that is independent of p53. Induction of apoptosis by agents such as actinomycin D, etoposide, and staurosporine and induction of necrosis by sodium azide were accompanied by an increase in the level of intracellular peroxy radicals and lipid peroxidation products, two independent end points that are typically associated with oxidative stress. Similar findings were observed in several subclones showing persistent apoptosis. These results suggest that the elevated levels of free radical damage that we detected were derived from the fraction of cells dying by apoptotic or necrotic processes. Possible mechanisms whereby oxidative stress may contribute indirectly to the perpetuation of chromosomal instability are discussed.     

Effects of hormonal replacement therapy on plasma sex hormone-binding globulin, androgen and insulin-like growth factor-1 levels in postmenopausal women

Plasma sex hormone-binding globulin (SHBG) levels are important in the regulation of plasma free and albumin-bound androgens and estrogens. In postmenopausal women associated to the decrease of estrogen production, a decrease of plasma SHBG levels occurs. Hormone replacement therapy (HRT) in postmenopausal women modulates plasma SHBG levels, in relationship with the different regimens and routes of administration. The present study aimed to compare the effect of different HRT on plasma SHBG levels in relationship with the changes of plasma androgen [dehydroepiandrosterone sulphate (DHEAS), testosterone (T), androstenedione (A)] and insulin-like growth factor-1 (IGF-1) levels. In a retrospective study 443 postmenopausal women were studied and divided into 2 groups. The group 1 (n = 170) was subdivided in 4 groups of women as follows: A) treated with transdermal 17-beta estradiol + medroxyprogesterone acetate, B) treated with oral conjugated estrogens, C) treated with sequential HRT (estradiol valerate (EV) + norgestrel), and D) treated with a combined HRT (micronized estradiol (E2) + noretisterone acetate). Women of group 2 (n = 273) did not receive HRT and served as controls. All groups of women treated with different HRT showed plasma estradiol levels significantly higher than controls (p < 0.01), showing the highest values in women treated with oral HRT. Plasma SHBG levels were not significantly different between patients treated with transdermal 17-beta estradiol + medroxyprogesterone acetate and controls. On the other hand, all the groups of patients treated with oral conjugated estrogen with or without progestagens showed plasma SHBG levels significantly higher than controls (p < 0.01). Plasma SHBG levels were higher in the group treated with estrogen alone than in groups of women treated with sequential or combined HRT. Plasma DHEAS, T and A levels in patients treated with different HRT regimens were in the same range of levels as control women. Plasma IGF-1 levels were not significantly affected by the various HRT regimens and remained in the same range as controls. In conclusion, plasma SHBG levels increase following oral HRT while are not affected by transdermal HRT. Plasma IGF-1 and androgen levels are not influenced from oral or transdermal HRT.     

Selective oxidation of indole by chloroperoxidase immobilized on the mesoporous molecular sieve SBA-15

The selective oxidation of hydrocarbons is an important value-enhancing chemical transformation in particular with respect to fine chemicals and pharmaceuticals production. Enzymatic oxidations operate under mild reaction conditions and produce little if any waste. However, its industrial use is still limited mainly due to their high cost and the low space time yields. In the present work, chloroperoxiase from Calariomyces fumago immobilized on the mesoporous molecular sieve SBA-15 was applied for the oxidation of indole to 2-oxoindole using hydrogen peroxide or tert.-butyl hydroperoxide as oxidants. The performance of the immobilized enzyme was found to be superior to native chloroperoxidase with respect to maximum conversion and pH range applicable. However, immobilized CPO is still sensitive to high concentrations of hydrogen peroxide. The use of tert.-buty hydroperoxide is found to avoid this problem, but the reaction rate is significantly reduced.     

Fabrication and mobility characteristics of SiGe surface channel pMOSFETs with a HfO/sub 2//TiN gate stack

This paper describes an extensive experimental study of TiN/HfO/sub 2//SiGe and TiN/HfO/sub 2//Si cap/SiGe gate stacked-transistors. Through a careful analysis of the interface quality (interface states and roughness), we demonstrate that an ultrathin silicon cap is mandatory to obtain high hole mobility enhancement. Based on quantum mechanical simulations and capacitance-voltage characterization, we show that this silicon cap is not contributing any silicon parasitic channel conduction and degrades by only 1 /spl Aring/ the electrical oxide thickness in inversion. Due to this interface optimization, Si/sub 0.72/Ge/sub 0.28/ pMOSFETs exhibit a 58% higher mobility at high effective field (1 MV/cm) than the universal SiO/sub 2//Si reference and a 90% higher mobility than the HfO/sub 2//Si reference. This represents one of the best hole mobility results at 1 MV/cm ever reported with a high-/spl kappa//metal gate stack. We thus validate a possible solution to drastically improve the hole mobility in Si MOSFETs with high-/spl kappa/ gate dielectrics.     

Accurate extraction of maximum current densities from the layout

A module for efficient extraction of maximum current densities from the layout has been developed and implemented within the CAD package PARIS. The corner-rounding dependence on technology parameters, such as numerical aperture and acid/base diffusion length, was simulated. A combination of classical and meshless FEM was used to obtain accurate results taking the simulated realistic shapes of the corners into account.     

Bestimmung natürlich vorkommender steroidaler Sexualhormone (Androgene und Gestagene) in Rindfleisch

The content of 10 naturally occurring steroidal sex hormones (androgens and progestogens), their biosynthetic precursors and metabolites was determined in 62 samples of beef (bulls, steers, heifers). After enzymatic hydrolysis of their conjugates, the steroids were extracted from the tissue by liquid-liquid extraction and purified by solid phase extraction. The identification and quantification was carried out by GC-MS of the trimethylsilyl ethers. The progestogens progesterone and pregnenolone were quantitatively dominant (43,7 and 6,5 μg/kg respectively). The highest steroid concentrations were determined in female cattle.     

Interaction of Kar2p and Sls1p is required for efficient co-translational translocation of secreted proteins in the yeast Yarrowia lipolytica

The yeast Yarrowia lipolytica is a model organism for in vivo study of the signal recognition particle-dependent targeting pathway. In this report, we defined solubilization conditions and set up a fractionation procedure of Y. lipolytica microsomes to determine the amounts of Sec61p-containing translocation pores linked to ribosomes. In contrast to Saccharomyces cerevisiae, from 70 to 80% of Sec61p associates with ribosomes in this yeast. The chaperone protein Kar2p and the Sls1p product, a resident protein of the endoplasmic reticulum lumen, partially fractionate with this Sec61p population. Moreover, Sls1p can be co-immunoprecipitated with Kar2p, and the two polypeptides are shown to directly interact in the yeast two-hybrid system. A site-directed mutagenesis was performed on the SLS1 coding sequence that allowed us to define a functional domain in Sls1p. Indeed, co-translational translocation of a reporter protein is affected when one of these mutant proteins is expressed. Moreover, this protein has lost its capacity to interact with Kar2p, and the two lumenal polypeptides might thus cooperate to promote secretory protein co-translational translocation.     

A versatile system for the generation and the development of speechcoding strategies in cochlear implants

A signal processor-based (DSP32C) stimulation system for cochlear implants has been developed. This system allows up to 14 stimulation channels (place principle) and conserves the time structure of the acoustic signal (periodicity principle). Any combination of these features is possible; in compressed analogue mode, pulsatile mode, or combinations of both. The system also takes electrical crosstalk into account caused by the electrical properties of the inner ear and compensates for it. Lateral inhibition strategies improve spatial resolution. Finally, the system offers an interface for the generation of quick continuous interleaved sampling strategies (CIS); up to 11000 pulses/s per channel