Determination of lactadherin concentration in dairy by-products by ELISA: Effect of heat treatment and hydrolysis

Lactadherin is a peripheral glycoprotein of the milk fat globule membrane with several attributed biological activities. In this study, we developed an indirect competitive ELISA to determine lactadherin concentration by using a rabbit polyclonal antiserum. The ELISA was applied to quantify lactadherin in several dairy by-products. Of the products tested, raw and commercial buttermilk had the highest concentrations of lactadherin (6.79 and 5.27 mg/g of product, respectively), followed by commercial butter serum (4.86 mg/g), commercial skim milk (4.84 mg/g), and raw whey (1.20 mg/g). The concentration of immunoreactive lactadherin was also determined in dairy by-products after they were subjected to different technological treatments. Thus, raw products were heat treated at combinations of temperature and time typically used in the dairy industry, and commercial products were hydrolyzed using 3 proteolytic enzyme preparations. Heat treatments of whey and buttermilk resulted in a smaller decrease in lactadherin concentration than did hydrolysis as determined by ELISA and electrophoresis. At high temperatures for long durations, the loss of lactadherin was higher in whey than in buttermilk, with the maximal reduction of around 48% found after treating whey at 72°C for 60 min. Hydrolysis of commercial products with proteolytic enzymes resulted in a marked decrease of immunoreactivity within the first 5 min of treatment, which thereafter was constant throughout 4 h of hydrolysis. These results demonstrate that dairy by-products from milk fat processing are good natural sources of lactadherin, although technological processes have to be considered, because they have different effects on lactadherin content.     

Visual kin recognition in nonhuman primates: (Pan troglodytes and Macaca mulatta): Inbreeding avoidance or male distinctiveness?

Faces provide important information about identity, age, and even kinship. A previous study in chimpanzees reported greater similarity between the faces of mothers and sons compared with mothers and daughters, or unrelated individuals. This was interpreted as an inbreeding avoidance mechanism where females, the dispersing gender, should avoid mating with any male that resembles their mother. Alternatively, male faces may be more distinctive than female faces, biasing attention toward males. To test these hypotheses, chimpanzees and rhesus monkeys matched conspecifics' faces of unfamiliar mothers and fathers with their sons and daughters. Results showed no evidence of male distinctiveness, rather a cross-gender effect was found: chimpanzees were better matching moms with sons and fathers with daughters. Rhesus monkeys, however, showed an overwhelming bias toward male-distinctiveness. They were faster to learn male faces, performed better on father–offspring and parent–son trials, and were best matching fathers with sons. This suggests that for the rhesus monkey, inbreeding avoidance involves something other than facial phenotypic matching but that among chimpanzees, the visual recognition of facial similarities may play an important role. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proposed Method for Determining the Interval for Hands-on Inspection of Steel Bridges with Fracture Critical Members

The proposed assessment procedure presented in this paper may be used to establish inspection intervals for steel bridges with fracture critical members (FCMs) (if adopted by the Federal Highway Administration). The procedure proposed herein only applies to FCM inspections which are defined as follows: a hands-on inspection of a FCM or member components that may include visual and other nondestructive evaluations. The method is rather simple and provides an alternative procedure to the pure calendar based inspection methodology currently specified in the Code of Federal Regulations for all FCMs. There are only two requirements which must first be satisfied in order to use the assessment. The first is that the routine 24-month inspection must continue to be performed on the bridge under evaluation. The second is that a FCM inspection must be performed on the bridge or the FCM under evaluation prior to the implementation of the resulting inspection intervals given from this assessment. The “initial inspection” should be performed as a typical FCM inspection. The assessment procedure is intended to be applied to individual FCMs and not the entire bridge itself. However, on bridges with multiple FCMs, the “worst case” FCM may be evaluated using the assessment and the resulting inspection interval may be applied to all FCMs on the bridge (for simplicity and bookkeeping purposes). The decision of whether to apply the assessment to all FCMs or the bridge’s worst case FCM is left up to the owner or engineer. The approach is not based on more rigorous damage tolerant design concepts or other fracture mechanics based methods. Nevertheless, the method is a first step in providing a more rational alternative to calendar based inspection and allows owners to prioritize structures and resource allocation. Using engineering experience and judgment, the interval for the hands-on inspection of steel bridges with FCMs can then be selected based on upper limits established through a consensus. Although the focus is on fracture critical bridges and members, the writers believe that the concept could be extended to a variety of structure types and configurations.     

Urinary Excretion of Ecdysterone and Its Metabolites Following Spinach Consumption

Scope

The phytosteroid ecdysterone is present in spinach. In this study, the urinary elimination of ecdysterone and its metabolites in humans is investigated following spinach consumption of two different culinary preparations.

Methods and results

Eight participants (four males, four females) ingested 950 (27.1) g sautéed spinach (average [±standard deviation (SD)]) and 912 (70.6) g spinach smoothie as second intervention after washout. Post-administration urines are analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). After intake of both preparations, ecdysterone and two metabolites, 14-deoxy-ecdysterone, and 14-deoxy-poststerone, are excreted in urine. The maximum concentration of ecdysterone is ranging from 0.09 to 0.41 µg mL⁻¹ after sautéed spinach and 0.08–0.74 µg mL⁻¹ after smoothie ingestion. The total excreted amount (mean% [±SD]) in the urine as a parent drug plus the metabolites is only 1.4 (1.0) for both sautéed spinach and smoothie. The apparent sex related differences in 14-deoxy-poststerone excretion will need further investigations.

Conclusion

Only a small proportion of ecdysterone from spinach is excreted into urine. No significant differences are found in concentration and recovered amount (%) of ecdysterone, 14-deoxy-ecdysterone, and 14-deoxy-poststerone in urine between sautéed spinach and smoothie ingestion. A discrimination between ecdysterone from food or preparations will be challenging based on urinary concentrations only, at least for later post-administration samples.