Enzyme-catalysed synthesis of calcium phosphates

A biomimetic method is described for the precipitation of nanosized calcium phosphates using the alkaline phosphatase (EC 3.1.3.1), which is responsible for hydrolysis of organic and inorganic phosphates in vivo. Buffered solutions containing glycerol-2-phosphate and CaCl₂ in addition to MgCl₂ and the respective enzyme were prepared for calcium phosphate precipitation. The phosphate group of glycerol-2-phosphate was cleaved through enzymatic hydrolysis. The local inorganic phosphate concentration increased resulting in the precipitation of nanosized calcium phosphates phases (Ca–P phase) composed of calcium deficient hydroxyapatite (CDHA) and hydroxyapatite (HA). At high Ca²⁺-concentration and large enzyme amounts mixed phases of HA/CDHA with an increasing quantity of HA were favoured. Under basic conditions (pH > 9) formation of HA was observed, whereas at neutral pH of 7.5 CDHA was primarily formed. The assignment of Ca–P phases was accomplished by FT-IR and Raman-spectroscopy in addition to X-ray diffractometry. The Ca–P materials exhibited BET surface areas of 173 m²/g. SEM-micrographs of the Ca–P powders showed globular-shaped agglomerates of Ca–P particles. The size of the Ca–P crystallite ranged from 9 nm to 25 nm according to transmission electron microscopy (TEM), where round-shaped, platelike and fibrelike crystallites were found. All crystallites showed diffuse ring patterns in electron diffraction confirming the nanosize of the precipitate. Using the developed technique, it was possible to synthesise 100 g of bonelike Ca–P materials in 1 day using 15 L batches with optimised parameters.     

Probiotic lactobacilli and bifidobacteria in a fermented milk product with added fruit preparation reduce antibiotic associated diarrhea and Helicobacter pylori activity

To investigate matrix-specifity of probiotic effects and particularly of the reduction of antibiotics-associated diarrhea, a controlled, randomized, double-blind study was performed, in which 88 Helicobacter pylori-infected but otherwise healthy subjects were given for eight weeks either a) a probiotic fruit yoghurt "mild" containing Lactobacillus acidophilus LA-5 plus Bifidobacterium lactis BB-12, n = 30), b) the same product but pasteurized after fermentation (n = 29) or c) milk acidified with lactic acid (control, n = 29). During week five, a Helicobacter eradication therapy was performed. Helicobacter activity was measured via 13C-2-urea breath tests and antibiotic-associated diarrhoea and other gastrointestinal complaints were recorded by validated questionnaires. In intervention group a, b and c the mean number of days with diarrhoea was 4, 10 and 10 (P<0·05), the frequency of episodes 17%, 7% and 27% (n.s.), and the change in total symptoms score before antibiotics treatment was -1·4 ± 1·1, -1·2 ± 1·1, 2·6 ± 1·1 points/four weeks (P<0·05). All milk products decreased Helicobacter activity by 18 to 45% without significant differences between groups. The observed decrease in Hel. pylori activity seems to be not or not only due to probiotic bacteria but (rather) to components of acidified milk (most probably lactic acid). Fruit-yogurt-like fermented milk products with living probiotic bacteria significantly shorten the duration of antibiotics-associated diarrhoea and improve gastrointestinal complaints. Fruit yogurt-like fermented milk is a matrix suitable for probiotic bacteria.     

Investigations into the mechanisms controlling parturition in cattle

A pronounced increase in fetal cortisol concentrations stimulating an increase in estrogen production at the expense of progesterone precursors in the placenta, luteolysis, and progesterone withdrawal is considered as a key event during the complex signal cascade leading to the initiation of parturition in cattle. However, there are many questions concerning the exact functional and/or temporal relationships between these individual processes which finally result in the expulsion of the calf and the timely release of the placenta. Thus, parturition was induced in 270-day pregnant cows using the progesterone receptor blocker aglepristone (group AG, n=3), the prostaglandin F(2α) analog cloprostenol (group PG, n=4), and the glucocorticoid dexamethasone (group GC, n=4) to characterize the effect on maternal steroid and prostaglandin levels and to identify immediate subsequent changes in placental morphology and gene expression as compared with untreated controls sampled on day 272 (group D272, n=3) and cows during normal parturition (group NT, n=4). All calves of the treatment groups were born on days 271-272, whereas gestational length in NT cows was 280.5±1.3 days. However, none of the treatments significantly induced the prepartal remodeling of placentomes characterized by a decline in trophoblast giant cells and reduction of the caruncular epithelium. Data on placental CYP17 and COX2 expression confirm that these key enzymes are upregulated by GC, whereas placental aromatase expression was not affected by any treatment. Maternal progesterone and prostaglandin profiles suggest differential effects of the treatments on luteal function and placental or uterine prostaglandin production. The results provide new information on the initiation of parturition in cattle but raise many new questions.     

Liquid chromatography and mass spectrometry in food allergen detection

Food allergy is an important issue in the field of food safety because of the hazards for affected persons and the hygiene requirements and legal regulations imposed on the food industry. Consumer protection and law enforcement require suitable analytical techniques for the detection of allergens in foods. Immunological methods are currently preferred; however, confirmatory alternatives are needed. The determination of allergenic proteins by liquid chromatography and mass spectrometry has greatly advanced in recent years, and gel-free allergenomics is becoming a routinely used approach for the identification and quantitation of food allergens. The present review provides a brief overview of the principles of proteomic procedures, various chromatographic set ups, and mass spectrometry instrumentation used in allergenomics. A compendium of published liquid chromatography methods, proteomic analyses, typical marker peptides, and quantitative assays for 14 main allergy-causing foods is also included.     

Response of Red Blood Cell Folate to Supplementation in Nonpregnant Women is Predictable: A Proposal for Personalized Supplementation

Scope

We modeled red blood cell (RBC)‐folate response to supplementation and developed personalized folate supplementation concepts.

Methods and results

The changes of RBC‐folate were modeled in a time‐ (4 or 8 weeks) and dose‐ (400 or 800 μg d^?1 folate) dependent manner. Post‐supplementation RBC‐folate levels were predicted from folate‐loading capacities (= measured RBC‐folate – [baseline RBC‐folate × RBC‐survival]). The prediction equations were validated in 119 participants. The median increase of RBC‐folate was higher in the 800 μg d^?1 than in the 400 μg d^?1 group (275 vs 169 nmol L^?1 after 4 weeks, and 551 vs 346 nmol L^?1 after 8 weeks). Medians (interquartile range) of RBC‐folate loading were (4 weeks: 299 (160) vs 409 (237) nmol L^?1) and (8 weeks: 630 (134) versus 795 (187) nmol L^?1) in the 400 and 800 μg d^?1 group, respectively. The individual measured and predicted RBC‐folate values (after 4 weeks/400 μg d^?1 = 25 + 1.27 × baseline RBC‐folate) and (after 4 weeks/800 μg d^?1 = 65 + 1.41 × baseline RBC‐folate) did not differ significantly. The measured and predicted concentrations showed high agreement in the validation cohort.

Conclusions

The models can guide nutritional recommendations in women when baseline RBC‐folate concentrations are measured and the time to pregnancy between 4 and 8 weeks.

     

Viability of Glioblastoma Cells and Fibroblasts in the Presence of Imidazole-Containing Compounds

The naturally occurring dipeptide carnosine (β-alanyl-L-histidine) specifically attenuates tumor growth. Here, we ask whether other small imidazole-containing compounds also affect the viability of tumor cells without affecting non-malignant cells and whether the formation of histamine is involved. Patient-derived fibroblasts and glioblastoma cells were treated with carnosine, L-alanyl-L-histidine (LA-LH), β-alanyl-L-alanine, L-histidine, histamine, imidazole, β-alanine, and L-alanine. Cell viability was assessed by cell-based assays and microscopy. The intracellular release of L-histidine and formation of histamine was investigated by high-performance liquid chromatography coupled to mass spectrometry. Carnosine and LA-LH inhibited tumor cell growth with minor effects on fibroblasts, and L-histidine, histamine, and imidazole affected viability in both cell types. Compounds without the imidazole moiety did not diminish viability. In the presence of LA-LH but not in the presence of carnosine, a significant rise in intracellular amounts of histidine was detected in all cells. The formation of histamine was not detectable in the presence of carnosine, LA-LH, or histidine. In conclusion, the imidazole moiety of carnosine contributes to its anti-neoplastic effect, which is also seen in the presence of histidine and LA-LH. Despite the fact that histamine has a strong effect on cell viability, the formation of histamine is not responsible for the effects on the cell viability of carnosine, LA-LH, and histidine.     

Zerstörungsfreie Ortung von Fehlstellen und Inhomogenitäten in Bauteilen mit der Impuls‐Thermografie

Non‐destructive detection of voids and inhomogeneities in building structures using impulse thermography. In the frame of a research project funded by the “Deutsche Forschungsgemeinschaft” the application of impulse thermography for the non‐destructive testing of building components and buildings is further developed by the Federal Institute for Material Research and Testing (BAM) and the Technical University of Berlin (TUB). To this aim measurements to several practical problems of civil engineering were carried out. The inspected specimen is pulse heated according to the problem. The following cooling down process is recorded with an infrared camera. The transient behaviour is afterwards analysed by numerical methods in the time domain and by means of Pulse‐Phase‐Thermography in the frequency domain. Pulse‐Phase‐Thermography in particular reduces the influence of inhomogeneous surfaces and non‐uniform heating on thermographic measurements.     

Inside Block Copolymer Micelles—Tracing Interfacial Influences on Crosslinking Efficiency in Nanoscale Confined Spaces

Recently, several studies have demonstrated the excellent capabilities of tip-enhanced Raman spectroscopyfor in-depth investigations of structural properties of matter with unprecedented resolution and chemical specificity. These capabilities are utilized here to study the internal structure of core-crosslinked micelles, which are formed by self-assembly of the diblock terpolymer poly(ethylene oxide)-block-poly(furfuryl glycidylether-co-tert-butylglycidyl ether). Supplementing force–volume atomic force microscopy experiments address additionally the nanomechanical properties. Particularly, TERS enables investigating the underlying principles influencing the homogeneity and efficiency of the Diels–Alder core-crosslinking process in the confined hydrophobic core. While the central core region is homogenously crosslinked, a breakdown of the crosslinking reaction is observed in the core–corona interfacial region. The results corroborate that a strong crosslinking efficiency is directly correlated to the formation of a mixed zone of the glycidyl ether and PEO corona blocks reaching ≈5 nm into the core region. Concomitantly a strong exclusion of the encapsulated bismaleimide crosslinker from the interfacial region is observed. It is conceivable that a changed structure, chemical composition and altered nanomechanical properties of this interfacial region may also influence the crosslinking efficiency across the entire core region by a modification of the solubility of the crosslinker in the interfacial core-corona region.