Metabolic profiling of normal and hypertensive rat kidney tissues by hrMAS-NMR spectroscopy

Intact kidney tissue samples of normal and spontaneously hypertensive rats (SHRs) were analyzed by hrMAS-NMR spectroscopy and principal component analysis (PCA). Radial components (cortex, outer stripe of the outer medulla, inner stripe of the outer medulla, and papilla) were sampled from various regions across the kidney from multiple animals in order to establish inter- and intra-animal variability. The effects of temperature were also measured. Papilla was differentiated from the other tissue types, and this variation by tissue type was greater than the effect of temperature on the samples (spectra were compared from samples at 2 and 30 °C). This study also revealed long term stability issues of tissue storage at -80 °C. The PCA showed that the greatest differentiation between normal rats and SHRs was found in the cortex and the regions in the NMR spectra that were correlated with this variation were identified.Abbreviations hrMAS High-resolution magic angle spinning - NMR Nuclear magnetic resonance - PCA Principal component analysis - CSA Chemical shift anisotropy - DD Dipolar coupling - SHR Spontaneously hypertensive rat     

A microwave-assisted sequential extraction of water and dilute acid soluble arsenic species from marine plant and animal tissues

This paper describes the use of dilute nitric acid for the extraction and quantification of arsenic species. A number of extractants (e.g. water, 1.5 M orthophosphoric acid, methanol-water and dilute nitric acid) were tested for the extraction of arsenic from marine biological samples, such as plants that have proved difficult to quantitatively extract. Dilute 2% (v/v) nitric acid was found to give the highest recoveries of arsenic overall and was chosen for further optimisation. The optimal extraction conditions for arsenic were 2% (v/v) HNO₃, 6 min⁻¹, 90 °C. Arsenic species were found to be stable under the optimised conditions with the exception of the arsenoriboses which degraded to a product eluting at the same retention time as glycerol arsenoribose. Good agreement was found between the 2% (v/v) HNO₃ extraction and the methanol-water extraction for the certified reference material DORM-2 (AB 17.1 and 16.2 μg g⁻¹, respectively, and TETRA 0.27 and 0.25 μg g⁻¹, respectively), which were in close agreement with the certified concentrations of AB 16.4 ± 1.1 μg g⁻¹ and TETRA 0.248 ± 0.054 μg g⁻¹.To preserve the integrity of arsenic species, a sequential extraction technique was developed where the previously methanol-water extracted pellet was further extracted with 2% (v/v) HNO₃ under the optimised conditions. Increases in arsenic recoveries between 13% and 36% were found and speciation of this faction revealed that only inorganic and simple methylated species were extracted.     

Low volume microwave digestion for the determination of selenium in marine biological tissues by graphite furnace atomic absorption spectroscopy

A microwave digestion method for the determination of marine biological tissues has been developed to allow determination of selenium in small sample sizes (< 0.1 g). The benefits of this technique include maintaining concentrates in extracts without the subsequent over dilution encountered when using larger vessels, increased sample throughput and reduced loss of volatile material. Freeze dried biological material (< 0.1 g) and nitric acid (1 ml) were placed into 7 ml screw top Teflon vessels which are completely sealed on capping. Two 7 ml vials were placed into larger 120 ml vessels fitted with a Teflon spacer and 10 ml of distilled water. The effects of microwave power and time, and sample mass on selenium recovery from three marine standard reference materials (NIST SRM 1566a Oyster Tissue, NRCC DORM-1 Dogfish Muscle and NRCC TORT-1 Lobster Hepatopancreas) were examined. The optimum conditions: 600 W, 2 min; 0 W, 2 min; 450 W, 45 min, allowed quantitative recoveries of selenium from these and three other standard reference materials (NRCC DOLT-1 Dogfish liver, NIST RM-50 Albacore tuna and IAEA MA-A-2 fish flesh). Studies on sample mass showed that the analysis of sample masses from 0.025 to 0.1 g gave selenium concentrations within the certified range. Six species of selenium: selenite, selenate, selenomethionine, selenocysteine, selenocystamine, and trimethyl selenonium were added to oyster, dogfish, and lobster tissues. Recoveries were near quantitative for all species (94–105%) except trimethyl selenonium (90–101%).     

Synthesis and evaluations of bisphosphonate‐containing monomers for dental materials

Two new bismethacrylamide ( 1 , 2 ) and two new methacrylamide ( 3 , 4 ) dental monomers were synthesized. In each group, one monomer contains a bisphosphonate group, the other a bisphosphonic acid group. Monomer 1 and 3 were synthesized by amidation of 2‐(2‐chlorocarbonyl‐allyloxymethyl)‐acryloylchloride and methacryloyl chloride with tetraethyl aminomethyl‐bis(phosphonate) and converted to the bisphosphonic acid monomers 2 and 4 by hydrolysis with trimethylsilyl bromide. Monomer 1 (m.p.: 71–72 °C), monomer 3 ( 33–34 °C), and monomer 4 (no m.p.) were obtained as white solids and monomer 2 a viscous liquid, soluble in water. Homopolymerization of 1 gave crosslinked polymers, indicating its low cyclization tendency. The photopolymerization studies indicated that its copolymerizability with 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane and 2‐hydroxyethyl methacrylate (HEMA) without changing their rates and conversions significantly means that it could be used as a biocompatible crosslinker. Although monomer 2 showed low polymerizability, because of its good performance in terms of solubility, hydrolytic stability, hydroxyapatite interaction, acidity, and copolymerizability with HEMA, it shows potential to be used in self‐etching dental adhesives. The thermal polymerization of 3 resulted in soluble polymers and evaluation of monomer 4 in terms of solubility, acidity, and copolymerizability with HEMA indicated its potential as an adhesive monomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Simultaneous analysis of bisphenol A based compounds and other monomers leaching from resin‐based dental materials by UHPLC–MS/MS

Resin‐based dental materials have raised debates concerning their safety and biocompatibility, resulting in a growing necessity of profound knowledge on the quantity of released compounds into the oral cavity. In this context, the aim of this study was to develop a comprehensive and reliable procedure based on liquid chromatography with mass spectrometry for the simultaneous analysis of various leached compounds (including bisphenol A based compounds) in samples from in vitro experiments. Different experiments were performed to determine the optimal analytical parameters, comprising mass spectrometry parameters, chromatographic separation conditions, and sample preparation. Four internal standards were used as follows: deuterated diethyl phthalate and bisphenol A (commercially available), and deuterated analogues of triethylene glycol dimethacrylate and urethane dimethacrylate (custom‐made). The optimized method was validated for linearity of the calibration curves and the associated correlation coefficient, lower limit of quantification, higher limit of quantification, and intra‐ and interassay accuracy and precision. Additionally, the developed liquid chromatography with tandem mass spectrometry method was applied to the analysis of leaching compounds from four resin‐based dental materials. The results indicated that this method is suitable for the analysis of different target compounds leaching from dental materials. This method might serve as a valuable basis for quick and accurate quantification of leached compounds from resin‐based dental materials in biological samples.     

An Enzyme-Linked Immunosorbent Assay for Determination of Dicyclanil in Animal Tissue

Dicyclanil is a toxic, pyrimidine-derived insect growth regulator used in veterinary medicine for the prevention of myiasis. A competitive indirect enzyme-linked immunosorbent assay was developed firstly for the determination of dicyclanil in animal tissue. The antigen was prepared using the glutaraldehyde method and polyclonal antibodies were obtained by immunizing rabbits with a dicyclanil-bovine serum albumin conjugate. The antibody obtained was specific for dicyclanil with an IC₅₀ of 9 ng/mL. Recoveries from sheep tissue and liquid milk were in the range of 52.5–72.4%, with coefficients of variation between 4.7% and 11.9%. The results were further confirmed by high performance liquid chromatography–tandem mass spectrometry.     

Novel B,O-chelated fluorescent probe for nitric oxide imaging in Raw 264.7 macrophages and onion tissues

A novel fluorescent probe based on B,O-chelated dipyrromethene chromophore in far-visible and near-infrared spectral region (600–900 nm), boron chelated 8-(3,4-diaminophenyl)-3,5-bis(2-hydroxyphenyl)-4-bora-3a,4a-diaza-s-indancene (BOPB), has been first developed for nitric oxide (NO) imaging. BOPB, a turn-on fluorescent probe, can react with NO rapidly under physiological condition. The reaction product of BOPB with NO, BOPB-T, emits bright red fluorescence at 643 nm when excited at 622 nm. Meanwhile, BOPB-T displays high fluorescent quantum yield of 0.21 and good photostability. The selectivity for NO over other reactive oxygen/nitrogen species and ascorbic acid has been investigated and BOPB has good specificity for the detection of NO. MTT assay shows that the toxicity of BOPB (below 10 μM) to living cells can be neglected. Based on these investigations, BOPB has been used for NO imaging in Raw 264.7 cells and onion tissues. Meanwhile, mechanical injury to onion tissues results in a brighter fluorescence around the wound, which indicates that more NO has been produced in plant tissues in response to external stimuli. Our studies illustrate that BOPB has advantages of high sensitivity, low background interference and little photo damage on fluorescence imaging of NO.     

Characteristics of Dietary Fatty Acids Isolated from Historic Dental Calculus of the 17th- and 18th-Century Inhabitants of the Subcarpathian Region (Poland)

Dental calculus analysis can be a valuable source of archaeological knowledge, since it preserves not only microbial and host biomolecules but also dietary and environmental debris, as well as metabolic products likely originating from dietary and craft activities. Here we described GC-MS analysis of a set of historic dental calculus samples from the front teeth of the mandibles of seven individuals found in 17th- and 18th-century graves in the city of Rzeszow, located in South-eastern Poland. We have found that only saturated fatty acids, which are characteristic for fats of animal origin, were present in the tested samples. Our preliminary results indicate that the diet of modern-period inhabitants of Rzeszow was rich in animal products, such as meat and dairy products.     

ToF‐SIMS spectrometry to observe fatty acid profiles of breast tissues in broiler chicken subjected to varied vegetable oil diet

This study is aimed to observe changes in fatty acid profiles by time of flight secondary ion mass spectrometry (ToF‐SIMS) in breast muscle tissues of broilers. Four different groups were identified. The source of fat in group I was soy oil (rich in linoleic acid, ω‐6), group II received linseed oil (ω‐3), and the third group was fed a mixture of the two mentioned oils. Broilers in the control group were fed with beef tallow, used in mass commercial production. The results reveal that the use of vegetable oils in animal nutrition determines the lipid profile of fatty acids. ToF‐SIMS measurements showed that the lipid profile of muscle fibers and intramuscular fat reflect the composition of fats used as feed additives. In both structures, the ratio of ω‐6/ω‐3 fatty acids, which is most favorable for human health, was found in the groups in which a mixture of vegetable oils and a supplement of linseed oil were used.