A case-control study of the effects of nephrolithiasis in cats with chronic kidney disease

OBJECTIVE: To determine whether nephrolithiasis was associated with an increase in mortality rate or in the rate of disease progression in cats with naturally occurring stage 2 (mild) or 3 (moderate) chronic kidney disease. DESIGN: Retrospective case-control study. ANIMALS: 14 cats with stage 2 (mild) or 3 (moderate) chronic kidney disease (7 with nephroliths and 7 without). PROCEDURES: All cats were evaluated every 3 months for up to 24 months. Possible associations between nephrolithiasis and clinicopathologic abnormalities, incidence of uremic crises, death secondary to renal causes, and death secondary to any cause were evaluated. RESULTS: There were no clinically important differences in biochemical, hematologic, or urinalysis variables between cats with and without nephroliths at baseline or after 12 and 24 months of monitoring. No associations were detected between nephrolithiasis and rate of disease progression, incidence of uremic crises, or death. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in cats with mild or moderate chronic kidney disease, nephrolithiasis was not associated with an increase in mortality rate or in the rate of disease progression. Findings support recommendations that cats with severe kidney disease and nephrolithiasis be managed without surgery.     

Cover Image,Volume 15, Issue 4

The cover image, by S. R. Lai et al., is based on the Original Article In vitro anti‐tubulin effects of mebendazole and fenbendazole on canine glioma cells, DOI: 10.1111/vco.12288

     

In vitro anti‐tubulin effects of mebendazole and fenbendazole on canine glioma cells

Benzimidazole anthelmintics have reported anti‐neoplastic effects both in vitro and in vivo. The purpose of this study was to evaluate the in vitro chemosensitivity of three canine glioma cell lines to mebendazole and fenbendazole. The mean inhibitory concentration (IC₅₀) (±SD) obtained from performing the MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay after treating J3T, G06‐A, and SDT‐3G cells for 72 h with mebendazole were 0.030 ± 0.003, 0.080 ± 0.015 and 0.030 ± 0.006 μM respectively, while those for fenbendazole were 0.550 ± 0.015, 1.530 ± 0.159 and 0.690 ± 0.095 μM; treatment of primary canine fibroblasts for 72 h at IC₅₀ showed no significant effect. Immunofluorescence studies showed disruption of tubulin after treatment. Mebendazole and fenbendazole are cytotoxic in canine glioma cell lines in vitro and may be good candidates for treatment of canine gliomas. Further in vivo studies are required.     

Concentrations of total glutathione and cysteine in wheat flour as affected by sulfur deficiency and correlation to quality parameters

A method for the simultaneous quantitation of total glutathione and total cysteine in wheat flour by a stable isotope dilution assay using high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) was developed. As internal standards, L-[(13)C3, (15)N]cysteine and L-gamma-glutamyl-L-[(13)C3, (15)N]cysteinyl-glycine were used. The method consisted of the extraction and reduction of flour with tris(2-carboxyethyl) phosphine after the addition of internal standards, protection of free thiol groups with iodoacetic acid, derivatization of free amino groups with dansyl chloride, and HPLC-MS/MS. The limits of detection and quantitation for glutathione were 0.75 nmol/g and 2.23 nmol/g flour, respectively. For cysteine, the limits of detection and quantitation were 0.72 nmol/g and 2.12 nmol/g flour, respectively. The developed method was found to be sensitive enough for quantitation of total glutathione and cysteine levels in wheat flour. This method was then utilized to investigate the effect of sulfur (S) deficiency on the amount of total glutathione and cysteine in flour. In S-deficient wheat, the concentrations of total glutathione and cysteine were proportional to the amount of S supplied during growth. The calculation of correlations revealed that GSH and Cys concentrations influenced the rheological dough properties and the baking performance at least as much as protein parameters. Thus, the low concentration of GSH and Cys in flour from S-deficient wheat had a similar effect on the technological properties as the altered composition of gluten proteins.     

Fractionation of cereal flour by sedimentation in non-aqueous systems. I. Development of the method and chemical characterisation of the fractions

A method for the fractionation of wheat, rye, and barley flours without using aqueous solvents was developed. The separation of protein and starch was based on differences in their densities. Therefore, ball-milled flour was suspended in a mixture of inert solvents (toluene/tetrachoroethene) with a density of 1.47 g/cm³ and centrifuged. Owing to its higher density, the starch fraction was obtained as sediment whereas the protein fraction (PF) formed a layer on the surface of the solvent because of its lower density. The PF was enriched in a solvent mixture with a density of 1.355 g/cm³ yielding a middle fraction (sediment) and the enriched PF (upper layer). The latter was then defatted with toluene (0.87 g/cm) providing a lipid fraction in addition. The influence of ball milling under air or in the sedimentation solvent on the yield and the purity of the fractions was studied. Three varieties of wheat, and one rye and barley variety were fractionated by the optimised method and the obtained fractions were characterised by chemical methods e.g. gel permeation chromatography, SDS electrophoresis, and a combined extraction/HPLC method.     

The Biochemical Basis of Celiac Disease

Celiac disease (CD) is an inflammatory disorder of the upper small intestine triggered by the ingestion of wheat, rye, barley, and possibly oat products. The clinical feature of CD is characterized by a flat intestinal mucosa with the absence of normal villi, resulting in a generalized malabsorption of nutrients. The prevalence of CD among Caucasians is now thought to be in a range of 1:100–300. There is a strong genetic association with human leukocyte antigens (HLA‐)DQ2 and DQ8 and currently unknown non‐HLA genes. During the last decade, intense biochemical studies have contributed to substantial progress in understanding the general principles that determine the pathogenesis of CD. The precipitating factors of toxic cereals are the storage proteins, termed gluten in the field of CD (gliadins and glutenins of wheat, secalins of rye, and hordeins of barley). There is still disagreement about the toxicity of oat avenins. The structural features unique to all CD toxic proteins are sequence domains rich in Gln and Pro. The high Pro content renders these proteins resistant to complete proteolytic digestion by gastrointestinal enzymes. Consequently, large Pro‐ and Gln‐rich peptides are cumulated in the small intestine and reach the subepithelial lymphatic tissue. Depending on the amino acid sequences, these peptides can induce two different immune responses. The rapid innate response is characterized by the secretion of the cytokine interleukin‐15 and the massive increase of intraepithelial lymphocytes. The slower adaptive response includes the binding of gluten peptides (native or partially deamidated by tissue transglutaminase) to HLA‐DQ2 or ‐DQ8 of antigen presenting cells and the subsequent stimulation of T‐cells accompanied by the release of proinflammatory cytokines such as interferon‐γ and the activation of matrix metalloproteinases. Both immune responses result in mucosal destruction and epithelial apoptosis. Additionally, stimulated T‐cells activate B‐cells that produce serum IgA and IgG antibodies against gluten proteins (antigen) and tissue transglutaminase (autoantigen). These antibodies can be used for noninvasive screening tests to diagnose CD. The current essential therapy of CD is a strict lifelong adherence to gluten‐free diet. Dietetic gluten‐free foods produced for CD patients underlie the regulations of the Codex Alimentarius Standard for Gluten‐Free Foods. The “Draft Revised Codex Standard” edited in March 2006 proposes a maximum level of 20 mg of gluten/kg for naturally gluten‐free foods (e.g., based on rice or corn flour) and 200 mg/kg for foods rendered gluten‐free (e.g., wheat starch). Numerous analytical methods for gluten determination have been developed, mostly based on immunochemical assays, mass spectrometry, or polymerase chain reaction. So far, only two enzyme‐linked immunosorbent assays have been successfully ring‐tested and are commercially available. During the last decade, future strategies for prevention and treatment of CD have been proposed. They are based on the removal of toxic epitopes by enzymatic degradation or gene engineering and on blocking parts of the immune system. However, any alternative treatment should have a safety profile competitive with gluten‐free diet.     

Development of a stable isotope dilution assay for the quantitation of glycidamide and its application to foods and model systems

On the basis of a stable isotope dilution assay and derivatization with 2-mercaptobenzoic acid, the presence of the carcinogenic glycidamide ( 2) in processed foods was verified for the first time. Using (13)C-labeled 2 as the internal standard and the formation of the thioether derivatives, a new stable isotope dilution assay for the quantitation of 2 was developed. Application of the method on several potato samples revealed amounts between 0.3 and 1.5 mug/kg depending on the processing conditions. In a model experiment, the formation of 2 by an epoxidation of the double bond in acrylamide, that is, by a reaction with linoleic acid hydroperoxides, was established. This result was in good agreement with data showing that French fries processed in sunflower oil, which is high in linoleic acid, contained more 2 as compared to fries prepared in coconut oil. The derivatization procedure allows the simultaneous quantitation of acrylamide and glycidamide in foods.     

Near-infrared reflectance model for the rapid prediction of total fat in cereal foods

AOAC method 996.01, used in cereal foods to determine total fat as defined by the U.S. Nutrition Labeling and Education Act (NLEA), is laborious and time-consuming and utilizes hazardous chemicals. Near-infrared (NIR) reflectance spectroscopy, a rapid and environmentally benign technique, was investigated as a potential method for the prediction of total fat using AOAC method 996.01 as the reference method. Near-infrared reflectance spectra (1104-2494 nm) of ground cereal products (n = 72) were obtained using a dispersive spectrometer, and total fat was determined according to AOAC method 996.01. Using multivariate analysis, a modified partial least-squares model was developed for total fat prediction. The model had a SECV of 1.12% (range = 0.5-43.2%) and a multiple coefficient of determination of 0.99. The model was tested with independent validation samples (n = 36); all samples were predicted within NLEA accuracy guidelines. The results indicate that NIR reflectance spectroscopy is an accurate means of determining the total fat content of diverse cereal products for nutrition labeling.     

Defoliation Effects on Herbage Production and Root Growth of Wet Meadow Forage Species

Root growth is important to the competitive ability of plants, and understanding how herbage defoliation affects root growth has implications for development of management strategies. Objectives were to determine the effects of defoliation intensity and frequency on root characteristics and herbage production of slender wheatgrass (Elymus trachycaulus [Link.] Shinners), Nebraska sedge (Carex nebrascensis C. Dewey), and “Steadfast” birdsfoot trefoil (Lotus corniculatus L.). Plants of each species were transplanted into containers that had been placed in the ground at wet meadow field sites the prior year. There were eight replications of a control and five defoliation treatments, which were combinations of different frequencies (two or five times) and intensities (light or heavy) and haying. Treatments were applied for a single growing season, and aboveground biomass was collected. Containers were extracted in October, and plant crowns, rhizomes, and roots were separated from the soil. Defoliation treatment did not affect total root weight, length, and surface area of Nebraska sedge or birdsfoot trefoil (P>0.10). Slender wheatgrass total root weight was less when defoliated five times (4.46 g·container^?1) than when defoliated twice (6.62 g·container^?1) during the growing season. More frequent defoliation of slender wheatgrass also reduced length (20%) and surface area (21%) compared to less frequent defoliation. However, defoliation frequency did not affect aboveground biomass. Defoliation intensity did not affect aboveground production or root characteristics of the three species. Abundant soil moisture in meadows likely buffers negative effects of defoliation. For all species, two defoliation events (e.g., haying followed by grazing) does not appear to negatively affect root growth and herbage production.