Replacement tunnelled dialysis catheters for haemodialysis access: Same site, new site, or exchange - a multivariate analysis and risk score.

AIM: To identify variables related to complications following tunnelled dialysis catheter (TDC) replacement and stratifying the risk to reduce morbidity in patients with end-stage renal disease. MATERIALS AND METHODS: One hundred and forty TDCs (Split Cath, medCOMP) were replaced in 140 patients over a 5 year period. Multiple variables were retrospectively collected and analysed to stratify the risk and to predict patients who were more likely to suffer from complications. Multivariate regression analysis was used to identify variables predictive of complications. RESULTS: There were six immediate complications, 42 early complications, and 37 late complications. Multivariate analysis revealed that variables significantly associated to complications were: female sex (p = 0.003; OR 2.9); previous TDC in the same anatomical position in the past (p = 0.014; OR 4.1); catheter exchange (p = 0.038; OR 3.8); haemoglobin <11 g/dl (p = 0.033; OR 3.6); albumin <30 g/l (p = 0.007; OR 4.4); prothrombin time >15 s (p = 0.002; OR 4.1); and C-reactive protein >50 mg/l (p = 0.007; OR 4.6). A high-risk score, which used the values from the multivariate analysis, predicted 100% of the immediate complications, 95% of the early complications, and 68% of the late complications. CONCLUSION: Patients can now be scored prior to TDC replacement. A patient with a high-risk score can be optimized to reduce the chance of complications. Further prospective studies to confirm that rotating the site of TDC reduces complications are warranted as this has implications for current guidelines.

CFTR is a tumor suppressor gene in murine and human intestinal cancer.

This corrects the article DOI: 10.1038/onc.2015.483.

CFTR is a tumor suppressor gene in murine and human intestinal cancer.

CFTR, the cystic fibrosis (CF) gene, encodes for the CFTR protein that plays an essential role in anion regulation and tissue homeostasis of various epithelia. In the gastrointestinal (GI) tract CFTR promotes chloride and bicarbonate secretion, playing an essential role in ion and acid-base homeostasis. Cftr has been identified as a candidate driver gene for colorectal cancer (CRC) in several Sleeping Beauty DNA transposon-based forward genetic screens in mice. Further, recent epidemiological and clinical studies indicate that CF patients are at high risk for developing tumors in the colon. To investigate the effects of CFTR dysregulation on GI cancer, we generated Apc(Min) mice that carried an intestinal-specific knockout of Cftr. Our results indicate that Cftr is a tumor suppressor gene in the intestinal tract as Cftr mutant mice developed significantly more tumors in the colon and the entire small intestine. In Apc(+/+) mice aged to ~1 year, Cftr deficiency alone caused the development of intestinal tumors in >60% of mice. Colon organoid formation was significantly increased in organoids created from Cftr mutant mice compared with wild-type controls, suggesting a potential role of Cftr in regulating the intestinal stem cell compartment. Microarray data from the Cftr-deficient colon and the small intestine identified dysregulated genes that belong to groups of immune response, ion channel, intestinal stem cell and other growth signaling regulators. These associated clusters of genes were confirmed by pathway analysis using Ingenuity Pathway Analysis and gene set enrichment analysis (GSEA). We also conducted RNA Seq analysis of tumors from Apc(+/+) Cftr knockout mice and identified sets of genes dysregulated in tumors including altered Wnt ß-catenin target genes. Finally we analyzed expression of CFTR in early stage human CRC patients stratified by risk of recurrence and found that loss of expression of CFTR was significantly associated with poor disease-free survival.

Quantitative determination of ochratoxin A by liquid chromatography/electrospray tandem mass spectrometry.

Mass spectrometry of ochratoxin A (OTA) and B (OTB) under electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) was studied. ESI offers higher sensitivities and less fragmentation than APCI. A sensitive LC/MS/MS method for the determination of ochratoxin A (OTA) in human plasma samples was developed. The absolute minimum detection limit was around 10-20 pg per injection, corresponding to 0.5 ppb in an injection equivalent to 20-40microg of human plasma. Ochratoxin B (OTB) was used as an internal standard and its absence in real-life samples was carefully checked before samples were spiked with the internal standard. It was found that these two ochratoxins are susceptible to sodium adduct formation. Fragment ions from the [M + H](+) and [M + Na](+) ions of both OTA and OTB were monitored in the multiple reaction monitoring mode. Three quantitative approaches, standard addition method, internal standard method (using ochratoxin B as an internal standard) and external standard method, were compared in the analysis of human blood plasma. Results from the mass spectrometric method were comparable to those from a conventional LC/fluorescence method. The LC/MS/MS method was also applied to the analysis of contaminated coffee samples.

Rose bengal strips.

I prepared rose bengal biological stain from its powder base to a 1% concentration. It was then impregnated into filter paper and allowed to air dry. The filter paper strips were sterilized and stored for individual use.

Gas chromatography-mass spectrometry of Alternaria mycotoxins.

Heptafluorobutyrate (HFB) derivatives have not previously been used for GC of Alternaria mycotoxins. Capillary (0.5 micron film) GC-mass spectrometry (MS) showed that full and partial derivatives of alternariol (AOH), alternariol monomethyl ether (AME) and altenuene (ALT); a structurally uncharacterized derivative of altertoxin I (ALTX-I); and a tris-HFB derivative of tenuazonic acid (TA) were formed with heptafluorobutyric anhydride and a basic catalyst. Full and partial trimethylsilyl (TMS) ethers of these mycotoxins were formed with Tri-Sil TBT. Apple juice extracts caused increased response in GC-MS of AOH bis-HFB and bis-TMS derivatives. Natural occurrence of AOH in apple juice has been demonstrated.

Determination of alternariol and alternariol methyl ether in apple juice using solid-phase extraction and high performance liquid chromatography.

The present work describes a new method for determination of alternariol (AOH) and alternariol methyl ether (AME) in apple juice using solid-phase extraction (SPE) columns for extraction and cleanup of samples for high-performance liquid chromatography (HPLC). Chromatograms of spiked samples show that both toxins can be easily detected without interferences, and good recoveries for AOH (82.8 +/- 7.4%) and AME (91.9 +/- 6.1%) with detection limits as low as 1.6 and 0.7 micrograms/l, respectively, were obtained.

Determination of the Fusarium mycotoxin beauvericin at micrograms/kg levels in corn by high-performance liquid chromatography with diode-array detection.

A method is described for the detection of the Fusarium mycotoxin beauvericin (BEA) in corn and corn meal. Spectral data obtained with a diode-array detector showed that the most sensitive wavelength for the detection of BEA is 192 nm. The detection limit for BEA was 50 micrograms/kg, which is an increase in sensitivity by a factor of at least twenty compared to previously published analytical methods for this mycotoxin.

Effects of deoxynivalenol (vomitoxin) on the humoral and cellular immunity of mice.

Sublethal doses (0.00, 0.25, 0.50 and 1.00 mg/kg b.w./day) of vomitoxin (deoxynivalenol; DON) were studied for their effects on humoral and cellular immunity and serum proteins of inbred, male Swiss Webster mice in a series of 4 separate experiments. Vomitoxin was added to basal diet (less than the detection limit, i.e., less than 0.05 micrograms of vomitoxin per g of feed) and administered to mice for 5 weeks beginning at 21 days of age. Mice in experiment 2 were fed the basal diet for 40 days in addition to the 5-week treatment with vomitoxin. The 1.00 mg/kg dose of vomitoxin resulted in a statistically significant reduction in the serum levels of alpha 1 and alpha 2-globulins, an increase in total serum albumin, and a reduction in feed consumption and body weight gain compared to the control group. The 0.50 mg/kg dose of vomitoxin resulted in significantly reduced serum levels of alpha 2- and beta-globulins while a significant reduction of feed consumption was evident only during Week 4. Similarly, body weight gain in this group of mice was significantly reduced during Week 2 but increased to normal levels during Week 3 and remained parallel to the control for Week 4 and 5. Both levels (0.50 and 1.00 mg/kg) of vomitoxin resulted in a reduced, dose-related, time-to-death interval following a challenge with L. monocytogenes and increased proliferative capacity of splenic lymphocyte cultures stimulated with the phytohemagglutinin P (PHA-P) mitogen compared to the control group of mice. The 0.25 mg/kg dose of vomitoxin did not have any significant effects on the parameters studied. A reasonable estimation of a 'no effect' level for immunologic effects in mice based on these and previous immunological studies would seem to be between 0.25 and 0.50 mg/kg b.w./day.

Fumonisins.

Fusarium moniliforme Sheldon is a common fungal contaminant of corn and produces a variety of mycotoxins. Among these are the recently discovered fumonisins, which are now known to cause certain animal diseases, namely leukoencephalomalacia in horses and pulmonary edema in swine. There is a significant association between their presence in corn and human esophageal cancer in southern Africa. Fumonisin B1 causes liver cancer in rats. Five other fumonisins--B2, B3, B4, A1 and A2, have been isolated; the last two are N-acetates of fumonisins B1 and B2 and do not appear to be toxic. Several other Fusarium species are now known to produce fumonisins. Procedures for detection and determination of fumonisins include thin layer chromatography, liquid chromatography (with fluorescence derivatization), post-hydrolysis gas chromatography, immunochemical assay, and mass spectrometry. In addition to their natural occurrence in corn-based animal feeds and in home-grown African corn used for food, fumonisins are frequently found in commercial corn-based foods. Fumonisins are moderately heat-stable. No effective detoxification process has yet been developed for use with fumonisin-contaminated feeds.

Mutagens produced by Alternaria alternata.

Alternariol, alternariol methyl ether and tenuazonic acid, metabolites present in Alternaria alternata cultures, were tested for mutagenicity with Salmonella typhimurium strains TA98 and TA 100. Alternariol methyl ether was weakly mutagenic to strain TA98 (without metabolic activation). Chromatographic separations of A. alternata mycelium extract yielded several fractions mutagenic in the latter system, including the altertoxin I fraction and a purified yellow pigment C20H14O6, which was characterized spectroscopically.

Seasonal variation in the incidence of congenital talipes equinovarus.

A review of 77 neonates who presented with congenital talipes equinovarus over a seven-year period revealed an increase in the condition amongst babies born in the winter quarter. This finding was particularly apparent among the less severe cases of club-foot. Possible reasons for this seasonal variation are discussed.

Approaches to the risk assessment of fumonisins in corn-based foods in Canada.

The presence of fumonisins and associated mycotoxins from Fusarium moniliforme in corn-based foods has recently become a concern in North America and elsewhere. Monitoring of various corn based foods and food commodities for fumonisins is ongoing in both the USA and Canada, and the results can be used for preliminary exposure assessments. The role of Fusarium moniliforme and the fumonisins in some diseases of livestock has been established. Considerable information is available on the mechanism of action of the fumonisins. With the availability of increased quantities of pure fumonisins, several subchronic toxicity studies, designed to establish dose response characteristics in rodents have now been completed. However, since concerns about the chronic toxicity of the fumonisins have not yet been adequately addressed, a tolerable daily intake cannot be established at this time. With the information at hand it is, nevertheless, possible to arrive at an interim risk assessment, which can be used to make interim risk management decisions. A total of 361 samples, covering 4 years of a Canadian survey, have been analyzed to date. Of these, 64 contained > or = 0.1 micrograms/g fumonisin B1, and 10 contained > or = 1 microgram/g. The 'all persons' estimate for the intake of fumonisins from these foods was < 0.089 micrograms/kg bw for 5-11 year-old children, and lower for other age groups. Based on an assessment of the available information on the toxicity of fumonisins, it can be concluded that these estimated intakes are unlikely to pose a health risk.

Biological fate of fumonisin B1 in food-producing animals.

The presence of mycotoxins in grains and feedstuffs causes not only animal health problems, but also a valid concern about the transmission of potentially toxic residues into animal-derived products intended for human consumption. In a series of studies at Agriculture and Agri-Food Canada, we investigated the biological fate of fumonisin B1 (FB1) in several food-producing animals (grower pigs, laying hens, dairy cattle), as well as monitored various parameters for evidence of toxicity in these species. In several experiments involving either single-dose protocols (iv, po) or longer-term feeding trials, the pharmacokinetic profiles of FB1 (purity > 95%) in these species were determined, including tissue accumulation and transmission of residues. Toxicological (and economical) implications such as performance (feed consumption, growth), productivity, and carcass quality were also measured when appropriate.

Mycotoxins transmitted into beer from contaminated grains during brewing.

Studies with aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, and fumonisins B1 and B2 added at various stages of the brewing process show that these mycotoxins (or metabolites) may be transmitted from contaminated grains into beer. Citrinin does not survive the mashing step. Mycotoxins in beer could originate from the malted grain or from adjuncts. Although high incidences and concentrations of aflatoxins and zearalenone have been found in local beers brewed in Africa, aflatoxins have not been detected in European beers. Zearalenone and alpha- or beta-zearalenol (the metabolite likely to occur) have not been found in Canadian and European beers, except for one sample analyzed by thin-layer chromatography only. Ochratoxin A rarely has been detected at > 1 ng/mL in beer; liquid chromatographic methods with a 0.05-0.1 ng/mL detection limit, however, have shown moderately high incidences of trace levels. Deoxynivalenol, which survives the brewing process, has been found with high incidence in Canadian and European beers, with concentration of > 200 ng/mL reported in several German beers. Fumonisins B1 and B2 occur to a limited extent in beer.

Analysis of agricultural commodities and foods for Alternaria mycotoxins.

Fungi of the genus Alternaria are parasitic on plants and other organic materials. A. alternata is a frequently occurring species of particular interest because it produces a number of mycotoxins, including alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxins I, II, and III (ATX-I, -II, and -III), and L-tenuazonic acid (TeA). Cleanup procedures of analytical methods for foods and foodstuffs include solvent partition, generally used for TeA, and solid-phase extraction columns for AOH, AME, and ATX-I. These Alternaria mycotoxins have been determined by TLC, GC, and more usually LC, mainly with ultraviolet detection, although fluorescence and electrochemical detection have also been used for Alternaria toxins other than TeA. A Zn2+ salt is usually added to the LC mobile phase for TeA. Recently, atmospheric pressure chemical ionization and electrospray LC/MS and LC-MS/MS have been applied to the determination and confirmation of AOH and AME in apple juice and other fruit beverages at sub ng/mL levels. Natural occurrences of AOH, AME, and in some cases other Alternaria toxins have been reported in various fruits, including tomatoes, olives, mandarins, melons, peppers, apples, and raspberries. They have been found also in processed fruit products such as apple juice, other fruit beverages and tomato products, wheat and other grains, sunflower seeds, oilseed rape meal, and pecans.

Stability and problems in recovery of fumonisins added to corn-based foods.

Because the natural occurrence of fumonisins is so far known almost exclusively in corn, we have limited our investigations on their stability to corn-based foods. In these studies, distinction must be made between real losses, binding, and any matrix-related method problems. Fumonisins B1 (FB1) and B2 (FB2) were about 40% recovered when heated in corn meal at 190 degrees C, about 20-30% recovered when heated in moist corn meal at 190 degrees C, and completely unstable in corn meal at 220 degrees C. Average recoveries of FB1 and FB2 added to blank heated matrixes were 69-107% in control experiments. Baking corn meal muffins spiked with 2.5 micrograms FB1 and FB2/g corn meal at 220 degrees C also resulted in losses of fumonisins. Little or no fumonisins were recovered from corn bran flour when methanol-water (3 + 1) was used as extraction solvent. However, when methanol-borate buffer (pH 9.2) (3 + 1) was used, recoveries averaged 91 +/- 17 and 84 +/- 9%, respectively, for FB1 and FB2; and natural contamination of the corn bran flour with FB1 and FB2 at levels of 1.9 and 0.95 microgram/g, respectively, was revealed. Comparable recoveries were observed for 1 brand of a corn bran breakfast cereal, but the binding effect was not seen with a second brand, for which methanol-water (3 + 1) alone was a good extraction solvent. Recoveries of FB1 and FB2 from a mixed cereal for babies were only about 50% with either extraction solvent mixture.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of aflatoxins in beer.

Aflatoxins B1, B2, G1, and G2 were determined at parts-per-trillion levels in beer by immunoaffinity column cleanup and reversed-phase liquid chromatography (LC) with fluorescence detection after trifluoroacetic acid derivatization. Silanized vials were necessary for the evaporation step in order to obtain good recoveries of aflatoxins from spiked beer samples. Recoveries averaged 90-104%, 94%, 84-87%, and 89% for aflatoxins B1, B2, G1, and G2, respectively, at levels of 9.7-133 ng B1, 46 ng B2, 35-140 ng G1, and 41 ng G2/L. Detection limits were 19-20 ng/L for aflatoxins B1 and G1 and 15-16 ng/L for aflatoxins B2 and G2 (signal-to-noise ratio = 3:1) obtained by using an excitation wavelength of 360 nm; at 340 nm these detection limits were lowered to about 2 ng/L. Analysis of 24 beer samples, the majority from the United States and Mexico, showed natural contamination of one sample of Mexican beer at 49 ng B1/L when determined at 360 nm excitation, but reanalysis of 23 of the samples using 340 nm excitation indicated that an additional 4 Mexican samples and one Brazilian sample contained aflatoxin B1 at low levels (< 10 ng/L).

Application of immunoaffinity columns to mycotoxin analysis.

Immunoaffinity columns (IACs) are widely used for cleanup and isolation of mycotoxins extracted from foods and biological fluids, particularly aflatoxins, ochratoxin A, and fumonisins. The columns are prepared by binding antibodies specific for a given mycotoxin to a specially activated solid-phase support and packing the support suspended in aqueous buffer solution into a cartridge. The mycotoxin in the extract or fluid binds to the antibody, impurities are removed with water or aqueous solution, and then the mycotoxin is desorbed with a miscible solvent such as methanol. Further separation can be performed with IAC, followed by liquid chromatographic (LC) quantitation, either off-line or on-line in an automated system, or by fluorometry. IACs have been used by laboratories that developed the antibodies but are also available commercially for aflatoxins, ochratoxin A, fumonisins, zearalenone, and deoxynivalenol. Among commercial IACs, Aflatest P is used as the cleanup step in an LC method and in a solution fluorometry method for corn, peanuts, and peanut butter that was adopted as an AOAC INTERNATIONAL Official Method after evaluation by an international collaborative study. As part of a fluorometer-based test kit, aflatest P was further certified by the AOAC Research Institute to measure total aflatoxins in 10 grains and grain products. IACs can concentrate the analyte from a large amount of sample, allowing detection limits at low parts-per-trillion levels in some cases (e.g., for aflatoxin M1 and ochratoxin A in liquid food matrixes). Regeneration of IACs for reuse in aflatoxin, ochratoxin A, fumonisin, and zearalenone analyses has been investigated.