Gluten contamination in the Canadian commercial oat supply.

A growing body of evidence suggests that a majority of people with celiac disease and on a gluten-free diet can safely consume pure oats in moderate amounts; however, previous studies have indicated that the commercial oat supply in other countries, and in Canada to some extent, is contaminated with other grains. This study has confirmed that the commercial oat supply in Canada is heavily contaminated with gluten from other grains. Approximately 88% of the oat samples (n = 133) were contaminated above 20 mg kg(-1) and there were no differences between the oat types tested. Only one gluten-free variety of oats was analysed and it consistently provided negative results in all analyses. It is difficult to determine where the contamination originates, but there are possibilities for cross-contamination in the field, in the transport of the grain, in the storage of the grain, and in the milling and packaging facilities. It is clear from this study that only those products that have been certified 'pure' oats would be appropriate for a gluten-free diet.

Human platelets express gangliosides with LKE activity and ABH blood group activity.

BACKGROUND: Platelets express several neutral glycosphingolipids with ABH and P blood group activity that may play a role in infectious, autoimmune, and alloimmune thrombocytopenia. In RBCs, sialylated glycosphingolipids or gangliosides with blood group activity have also been reported. To determine whether similar antigens are expressed by platelets, the total platelet ganglioside fraction was isolated and screened for blood-group-active glycosphingolipids. STUDY DESIGN AND METHODS: Platelet gangliosides were isolated by organic extraction, base hydrolysis, anion exchange, silicic acid, and high-performance liquid chromatography. Gangliosides were identified and characterized by high-performance thin-layer chromatography-immunostaining with blood group-specific MoAbs and glycosidase digestion. RESULTS: Group A, but not group O, platelets express five gangliosides with group A activity. Of five A MoAbs and lectins examined, only MoAbs Birma-1 and MHO4 recognized all five sialyl A bands. The sialyl A bands were sensitive to endoglycoceramidase and neuraminidase. One sialyl A band may represent a branched ganglioside with sialyl-I and group A activity. Platelets also express an LKE-active ganglioside consistent with sialyl-galactosylgloboside. CONCLUSION: In addition to sialyl-iI and sialyl-Le(x) gangliosides, group A platelets express gangliosides with LKE activity and group A activity. Like RBCs, group A-active gangliosides may act as alloantigens and autoantigens to naturally occurring isohemagglutinins.

Evidence of a phospholipid binding species within human fibrinogen preparations.

Fibrinogen has been reported to interact with phospholipid; however, the properties of this binding interaction have not been characterized. Purified preparations of human fibrinogen bound to small unilamellar vesicles containing phosphatidylserine (PS) as measured by light scattering and radioisotope filtration. Binding to 100% PS was saturable (apparent Kd=5 microM, Bmax=1.9 g protein/g lipid), reversible, and involved a minor subfraction of the fibrinogen preparation (3-6% of total protein). Fibrinogen interacted minimally with phosphatidylinositol, and not at all with pure phosphatidylcholine (PC) or PC vesicles containing 5% glycosphingolipid (lactosylceramide, ganglioside GM3, ganglioside GD3). Binding efficiency decreased as the PS content of vesicles was diluted with PC. Calcium chloride (2 mM) enhanced protein binding to PS, which was reversed by EDTA. Fibrin clot formation almost quantitatively precipitated the PS binding activity. PS, but not PC, increased the final turbidity of fibrin clots. Computerized sequence analysis of fibrinogen revealed three candidate acidic phospholipid binding motifs located at position 143-210 in the alpha chain, and positions 59-77 and 101-139 in the beta chain. Further study of the PS binding activity of fibrinogen may lead to new insights about fibrinogen function.

Shiga toxin binds human platelets via globotriaosylceramide (Pk antigen) and a novel platelet glycosphingolipid.

Hemolytic-uremic syndrome is a clinical syndrome characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia that often follows infection by Shiga toxin- or verotoxin-producing strains of Escherichia coli. Because thrombocytopenia and platelet activation are hallmark features of hemolytic-uremic syndrome, we examined the ability of Shiga toxin to bind platelets by flow cytometry and high-performance thin-layer chromatography (HPTLC) of isolated platelet glycosphingolipids. By HPTLC, Shiga toxin was shown to bind globotriaosylceramide (Gb3) and a minor platelet glycolipid with an Rf of 0.03, band 0.03. In a survey of 20 human tissues, band 0.03 was identified only in platelets. In individuals, band 0.03 was expressed by 20% of donors and was specifically associated with increased platelet Gb3 expression. Based on glycosidase digestion and epitope mapping, band 0.03 was hypothesized to represent a novel glycosphingolipid, IV3-beta-Galalpha1-4galactosylglobotetraosylceramide. Based on incidence, structure, and association with increased Gb3 expression, band 0.03 may represent the antithetical Luke blood group antigen. By flow cytometry, Shiga toxin bound human platelets, although the amount of Shiga toxin bound varied in donors. Differences in Shiga toxin binding to platelet membranes did not reflect differences in platelet Gb3 expression. In contrast, there was a loose association between Shiga toxin binding and decreasing forward scatter, suggesting that Shiga toxin and verotoxins bind more efficiently to smaller, older platelets. In summary, Shiga and Shiga-like toxins may bind platelets via specific glycosphingolipid receptors. Such binding may contribute to the thrombocytopenia, platelet activation, and microthrombus formation observed in hemolytic-uremic syndrome.

The specific hospital significantly affects red cell and component transfusion practice in coronary artery bypass graft surgery: a study of five hospitals.

BACKGROUND: Interhospital differences in blood transfusion practice during coronary artery bypass graft (CABG) surgery have been noted, but the underlying issues have not been identified. STUDY DESIGN AND METHODS: Records of 3217 consecutive CABG cases in five university teaching hospitals in 1992 and 1993 were stratified by hospital, type of revascularization conduit, patients' sex, and other factors. Statistical methods were used to compare patient characteristics, transfusion outcomes, and hospital outcomes. RESULTS: Forward two-step logistic regression using patient likelihood of red cell transfusion factors in the first step and the specific hospital in the second step revealed a significant effect of hospital on the delta odds ratios for red cell transfusion. This finding was confirmed by analyses of a highly stratified subset of cases, males in diagnosis-related group 107 (primary cases of coronary bypass without coronary catheterization) who underwent revascularization with venous and internal mammary artery grafts, revealing variations among hospitals from 109 to 457 units of red cells transfused per hundred cases. Corresponding variations in transfusions of all blood components were from 324 to 1019 units by hospital. Variation in red cell transfusion practice among surgeons in the same hospital was not responsible for these interhospital differences. CONCLUSION: The effect of the specific hospital on transfusion practice is attributed to institutional differences that, through reasons of training or hierarchy, become ingrained in hospitals.

A new method of determining chlorine kinetic isotope effects.

Two methods have been used to measure the chlorine leaving group kinetic isotope effect for the S(N)2 reduction of benzyl chloride to toluene by sodium borohydride in DMSO at 30.000 °C. The reaction was monitored by titrating the unreacted borohydride ion. One method involved determining the chlorine isotope effect using the classical IRMS method, which requires the conversion of the chloride ions into gaseous methyl chloride that is analyzed in an isotope ratio mass spectrometric analyses (Hill, J. W.; Fry, A. J. Am. Chem. Soc. 1962, 84, 2763. Taylor, J. W.; Grimsrud, E. P. Anal. Chem. 1969, 41, 805.). Two different measurements using this method yielded isotope effects of k(35)/k(37) = 1.007 19 ± 0.000 19 and 1.007 64 ± 0.000 19. The second method was a new technique where the ratio of the chlorine isotopes was obtained by fast atom bombardment mass spectrometry on the silver chloride recovered from the reaction, i.e., from the first step in the classical procedure. Therefore, the new method is much simpler and avoids the time-consuming preparation, purification, and recovery of the gaseous methyl chloride. Although the experimental error is larger (k(35)/k(37) = 1.008 03 ± 0.00 10 and 1.008 02 ± 0.000 65) when the new technique is used to analyze the silver chloride samples from the same set of experiments that were used to measure the isotope effect by the classical method, the chlorine isotope effect found by the two methods is identical within experimental error. This large chlorine kinetic isotope effect indicates there is considerable C(α)-Cl bond rupture in the S(N)2 transition state.

Determinants of red cell, platelet, plasma, and cryoprecipitate transfusions during coronary artery bypass graft surgery: the Collaborative Hospital Transfusion Study.

BACKGROUND: Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery. STUDY DESIGN AND METHODS: To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis-related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993. RESULTS: The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections. CONCLUSION: The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in-hospital outcomes.

Multiple glycosphingolipids determine the tissue tropism of parvovirus B19.

Infection with human parvovirus B19, the etiologic agent of fifth disease, is associated with numerous hematologic and nonhematologic complications. Recently, the receptor for parvovirus B19 was reported to be globoside (Gb4), a neutral glycosphingolipid (GSL) of red cell membranes. To ascertain if tissue Gb4 expression correlates with B19-associated disease, neutral GSLs from 16 human tissues were isolated and analyzed using high-performance thin-layer chromatography and immunostaining with anti-Gb4 monoclonal antibodies or B19 empty capsids. Gb4 was identified as a major neutral GSL in 11 tissues, especially in those of mesodermal origin. In addition to recognizing Gb4, B19 capsid bound to several tissue-specific GSLs, including two complex globo series GSLs (SSEA-3, SSEA-4) and paragloboside (neolactotetraglycosylceramide), as was demonstrated in red cell, granulocyte, kidney, liver, and bowel tissue. There was good correlation between tissue-neutral GSL expression, B19 capsid binding, and the tissue tropism observed clinically in B19 parvovirus-associated disease.

Detection in human blood platelets of sialyl Lewis X gangliosides, potential ligands for CD62 and other selectins.

Activated platelets are known to express P-selectin, a lectin-like adhesion receptor (CD62), through which they bind to sialyl Lewis X (sLex) ligands displayed on the membranes of leukocytes. To determine whether direct platelet-platelet interactions via P-selectin/sLex interactions are also possible, we have examined the ganglioside extract of human blood platelets for the presence of sLex ligands. Using the sensitive method of high-performance thin-layer chromatography (HPTLC)-immunostaining with the monoclonal antibody (mAb) CSLEX or with sialidase followed by mAbs MC480 or PM81, eight sLex bands were demonstrated at Rf 0.01, 0.03, 0.05, 0.06, 0.08, 0.10, 0.14 and 0.21 in the solvent 45:55:10 chloroform-methanol-aqueous 0.02% CaCl2. The sensitivity of all eight bands to sialidase or endoglycoceramidase confirmed that they were gangliosides. Comparison of the HPTLC mobilities and densities of platelet bands with those from five other human tissues (granulocytes, monoblasts, kidney, aortic endothelium and erythrocytes) in three different solvents revealed three major bands associated with platelets: 3 (Rf0.03), 6 (0.08) and 14 (0.21). Platelet bands were demonstrated not to have resulted from granulocyte contamination. Partial purification of platelet sLex gangliosides by high-performance liquid chromatography and their reaction with 14 oligosaccharide-specific mAbs (FH4, FH5, LM112-161, LM119-181, A5, 1B2, BR55-2, BE2, ES4, MC631, MH04, SH34, P001 and MC813-70) revealed that band 6 is a multifucosylated neolacto ganglioside and band 14 is a branched, disialo neolacto fucoganglioside. Platelet band 3 combined the features of both bands 6 and 14, and reacted differently than granulocyte band 3. These partial structures resemble gangliosides associated with adhesion in other cell systems. It is concluded that platelets express tissue-specific sLex gangliosides (sLex ligands). Thus, it is possible that platelet-platelet binding may be mediated at least partially through P-selectin/sLex interactions, especially after platelet activation.

The 1901 uganda sleeping sickness epidemic revisited: a case of mistaken identity?

The great sleeping sickness epidemic that occurred in Busoga at the turn of the century was caused by a trypanosome identified by Bruce as Trypanosoma gambiense. A study of trypanosomes from the recent epidemic in southeast Uganda has shed new light on the origins of the disease in Busoga. Thorsten Koerner, Peter de Raadt and Ian Maudlin suggest that the epidemic of the turn of the century was of T. p. rhodesiense sleeping sickness, brought about then, as now by social upheaval.

Cloning and characterization of COX14, whose product is required for assembly of yeast cytochrome oxidase.

Nuclear respiration-deficient mutants of Saccharomyces cerevisiae previously assigned to complementation group G93 lack cytochromes a and a3 and detectable cytochrome oxidase activity. Other respiratory chain carriers and the ATPase complex are present at near wild-type levels, indicating that the mutations specifically affect cytochrome oxidase. Since synthesis of the mitochondrially derived subunits 1, 2, and 3 of cytochrome oxidase is normal, the defect cannot be related to transcription of the endogenous genes or processing and translation of the corresponding RNAs. The results of Western analysis of the cytochrome oxidase subunits encoded in nuclear DNA also argues against an effect of the mutations on expression of these constituents. The G93 mutants are complemented by a nuclear gene, designated COX14. The product of this gene is a low molecular mass protein of 7,960 Da. A gene fusion expressing a biotinylated form of Cox14p complements cox14 mutants, indicating partial functional equivalence. The biotinylated derivative has been helpful in localizing Cox14p to the mitochondrial membrane and demonstrating that it is not a hitherto unrecognized subunit of cytochrome oxidase, although it does appear to be associated with a high molecular weight complex. This evidence, combined with the assembly-arrested phenotype of cox14 mutants, indicates that Cox14p, like several other recently described mitochondrial constituents, provides an important function at some late stage of the cytochrome oxidase assembly pathway.

Helicobacter pylori eradication reduces the rate of rebleeding in ulcer hemorrhage.

To evaluate whether eradication with omeprazole and amoxicillin results in a reduction of ulcer recurrence and rebleeding in patients with Helicobacter pylori-associated duodenal ulcer hemorrhage, patients with upper gastrointestinal hemorrhage from duodenal ulcers with stigmata of recent hemorrhage, a drop in hemoglobin level of more than 2 g/dL, and documented H. pylori infection (by rapid urease test and histologic findings) were randomly assigned to receive omeprazole, 40 mg every day, and amoxicillin, 1 g twice a day, (Group A) or omeprazole alone, 40 mg every day, (Group B) for 2 weeks. No maintenance antiulcer therapy was given. Patients underwent a second endoscopy 4 weeks after completion of therapy and were followed for 1 year. Endoscopy was performed again at the end of 1 year. All patients showed ulcer healing 4 weeks after completion of therapy. H. pylori eradication rates were 83% (Group A) and 5% (Group B) (p < .001). Ulcer recurrences were significantly lower in Group A (3/29 or 10%) than in Group B (9/22 or 41%; p < .05). Comparison of Group A patients with eradication and Group B patients without eradication also revealed a significant difference in rates of ulcer relapse (1/24 or 4% versus 9/21 or 43%; p < .01). Rebleeding occurred significantly less often in the dual therapy group than in the omeprazole group (0/29 versus 6/22 or 27%; p < .01). Eradication of H. pylori significantly reduces the rates of ulcer recurrence and rebleeding in patients with duodenal ulcer bleeding. Dual therapy with omeprazole and amoxicillin should be considered in all H. pylori-positive patients with hemorrhage from duodenal ulcers.

Concurrent comparison of the safety of paid cytapheresis and volunteer whole-blood donors.

BACKGROUND: Historically, paid blood donors were found to transmit hepatitis at higher rates than volunteers. In those older studies, paid donors frequently were recruited from prisons or slum areas--a finding consistent with the belief that monetary payment in itself did not necessarily lead to the high-risk status of commercial blood. Instead, it was the population base from which the donors were recruited that was important. STUDY DESIGN AND METHODS: Today, cytapheresis donors are in great demand. Because payment is one incentive that might entice donors to undertake the increased commitment of repeated cytapheresis donation, the results were studied of infectious disease history and laboratory testing performed concurrently in 917 volunteer whole-blood donors and 1240 paid cytapheresis donors, who were enrolled in distinct programs at the DeGowin Blood Center from October 7, 1987, through November 30, 1990. RESULTS: When first, repeat, and overall donations made by these donors were evaluated separately, paid cytapheresis donors were found to exhibit no increase in infectious disease history or test results beyond those of volunteer whole-blood donors. CONCLUSION: Thus, paid cytapheresis donors, when managed within a formal program, should not necessarily be presumed to be more dangerous than volunteers, from an infectious disease aspect. However, definitive proof of safety (comparison of transfusion-transmitted infection rates in two groups of patients receiving blood components exclusively from either paid cytapheresis or volunteer donors) was not pursued by long-term follow-up studies.

Proctoscopic Doppler ultrasound in diagnostics and treatment of bleeding hemorrhoids.

PURPOSE: Endoscopic Doppler sonography is a relatively new technique in the diagnostics of intestinal hemorrhage. It has been used mainly for bleeding gastroduodenal ulcers, but can also be utilized in the lower digestive tract. METHODS: In the study presented 80 patients with symptomatic hemorrhoids of first degree and previous hemorrhage were randomized in two groups. The 40 patients in Group A were examined by transproctoscopic Doppler ultrasound. After measuring the vessels depth, local injection treatment with 5 percent phenol almond oil followed. The patients in Group B had been given conventional sclerotherapy without the aid of Doppler investigation. The success of treatment was checked using Doppler sonographics six weeks later and the results were statistically compared. RESULTS: In the patients in Group A, the hemorrhoids proved to be totally eliminated in 93 percent vs. 38 percent of the patients in Group B (P, 0.1 percent). CONCLUSIONS: Proctoscopic Doppler ultrasound is useful in the evaluation and sclerotherapy of symptomatic first-degree hemorrhoids.

The 3G11+ antigen, a marker for murine CD4+ TH1 lymphocytes, is a ganglioside.

Two monoclonal antibodies (mAbs), SM3G11 and SM6C10, can be used to discriminate between functionally distinct murine CD4+ T cell subsets. In this study we use high-performance thin-layer chromatography and immunostaining techniques to show that the 3G11 mAb reacts with two bands of a ganglioside fraction from murine spleen and thymus, and rat spleen. The 6C10 antibody shows no evidence of glycolipid reactivity. The 3G11+ bands have a mobility between those of the reference gangliosides GD1a and GD1b from human brain. The 3G11+ reactive bands were eluted in the disialyl fraction of rat spleen gangliosides using DEAE anion-exchange chromatography. Treatment of spleen gangliosides with endoglycoceramidase eliminates 3G11 antibody binding over time, indicating that the antigen contains a Glc beta 1-1'ceramide linkage, characteristic of a glycosphingolipid. Treatment of thymus or spleen gangliosides with sialidase eliminates binding of 3G11, thus indicating that the 3G11 epitope is dependent on the expression of one or more sialic acid residues. Immunostaining studies with a variety of reagents indicate that the 3G11+ gangliosides: (i) probably do not contain either the asialo-GM1 or the GM1 core structures; (ii) are not recognized by mAbs specific for the oligosaccharides of asialo-GM2, GM2, GD2 and GD3 gangliosides; and (iii) are also not recognized by antibodies or reagents that are specific for several structures representative of other major glycosphingolipid classes. Overall, these studies strongly suggest that the 3G11+ gangliosides have structures that have not been previously recognized in murine lymphoid tissue. Structures that could account for the known properties of the 3G11+ molecules are described. Finally, ways in which the selective expression of 3G11+ gangliosides might be linked to functionally distinct T-cell behaviours are discussed.

Glycosphingolipid inhibition of the adhesion of thrombin-activated platelets to surfaces is potentiated by albumin.

Previous studies have shown that exogenous glycosphingolipids (GSLs) inhibit the adhesion of thrombin-activated platelets (TAP) to polystyrene plates coated with various RGD-ligands (where RGD is the peptide sequence Arg-Gly-Asp), suggesting that GSLs can modulate the platelet integrin receptor glycoprotein IIb-IIIa. However, albumin was always used as a plastic surface-blocking agent in these studies. In order to evaluate the role of albumin in these experiments, we studied the effect of various GSLs and albumin on the interaction between TAP and hydrophobic surfaces in a solid-phase assay using indium-111-labelled platelets and polystyrene plates. TAP (10(8) platelets/ml) adhered to polystyrene (half-saturation time 40 +/- 3 min) with a maximal adhesion density of 56 +/- 1 x 10(3) platelets/mm2. Platelet adhesion was only slightly affected (< 11% inhibition) by immobilized bovine serum albumin, immobilized mixed bovine brain gangliosides (MBG) or fluid-phase MBG. In contrast, fluid-phase MBG was an effective inhibitor of platelet adhesion to polystyrene (> 46% inhibition), but only after albumin was first immobilized to the plate. Covering albumin-coated polystyrene with MBG, followed by washing, was as effective as fluid-phase MBG at inhibiting platelet adhesion, thus indicating that a ganglioside-albumin interaction at the polystyrene surface was responsible for effective inhibition. When purified GSLs were substituted for MBG, it was found that all those tested (GT1b, GD1a, GM1, asialo GM1 and globoside) had similar inhibitory activity.

Structure of an extracellular polysaccharide produced by Erwinia chrysanthemi.

Erwinia chrysanthemi pv zeae strain SR260, a phytopathogen of corn, produced from lactose an acidic extracellular polysaccharide which was purified and found to consist of L-rhamnose, D-mannose, D-glucose, and D-glucuronic acid in the ratio of 3:1:1:1. A combination of chemical (carboxyl-group reduction, methylation analysis, periodate oxidation, Smith degradation, and lithium-ethylenediamine degradation) and physical (1 and 2D NMR spectroscopy) methods revealed that the polysaccharide is composed of a hexasaccharide repeating unit 1: [formula: see text]

Doppler-controlled injection treatment of Dieulafoy's disease.

Dieulafoy's anomaly is a vascular malformation of the upper stomach, which typically causes massive and recurrent haemorrhage. Emergency endoscopy is the most effective method of diagnosing the disease. Until recently, the therapy of choice was surgical resection. Five patients with spontaneously stopped bleeding from Dieulafoy's ulceration were investigated. Transendoscopic Doppler ultrasound was used to identify arterial blood flow from the lesions. Local injection treatment was performed. Successful therapy resulted in the disappearance of arterial pulsations and no rebleeding occurred. The endoscopic Doppler is of diagnostic value in the evaluation of Dieulafoy's ulcer and enables control of endoscopic sclerotherapy.