ON GUAIACOL SOLUTIONS : I. THE ELECTRICAL CONDUCTIVITY OF SODIUM AND POTASSIUM GUAIACOLATES IN GUAIACOL

1. Measurements on the densities, viscosities, dielectric constants, and specific conductances of pure anhydrous and water-saturated guaiacol at 25°C. are reported. 2. The solubility of water in guaiacol at 25°C., and its effect on the electrical conductivity of a sodium guaiacolate solution is given. 3. Electrical conductivity measurements are reported on solutions of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C. 4. The decrease of electrical conductivity with increasing concentration for these salts is explained on the basis of an ionic equilibrium combined with the interionic attraction theory of Debye and Hückel. 5. The limiting equivalent conductances of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C., the corresponding limiting ionic mobilities, and the dissociation constants are computed from the conductivity measurements. The salts are found to be weak electrolytes with dissociation constants of the order of 5 x 10^–6.

ON GUAIACOL SOLUTIONS : II. THE DISTRIBUTION OF SODIUM AND POTASSIUM GUAIACOLATES BETWEEN GUAIACOL AND WATER

1. Measurements are reported on the distribution of sodium and potassium guaiacolates between guaiacol and water at 25°C. 2. The variation of the partition coefficients with the concentration is explained with the aid of the Debye-Hückel interionic attraction theory and the assumption that the salts are strong electrolytes in water and weak electrolytes in guaiacol. 3. The dissociation constants of sodium and potassium guaiacolates in guaiacol previously computed from electrical conductivity determinations are shown to be in agreement with the corresponding values obtained from the distribution measurements. 4. From theoretical considerations an equation is derived with which it is possible to predict the magnitude of the limiting partition coefficients from the dielectric constants of the solvents, the size of the solute ions, and the temperature.

Angiodysplasia as a cause of Gastrointestinal Bleeding in Childhood

Whereas in adults angiodysplasia is a frequent cause of gastrointestinal bleeding, in children this disorder is extremely rare. A 7 10/12 year old girl is presented suffering over 3-4 months from mild but recurrent rectal bleeding. Blood count and serum ferritin and transferrin levels were normal. The rectosigmoideoscopy revealed a rectal lesion, which was confirmed histologically as angiodysplasia. Pathological investigation of the biopsies included HE staining and immunohistological staining of endothelial cells with anti-CD34 and anti-von Willebrand factor. A follow-up period of three years revealed spontaneous regression of the angiodysplastic lesion at the rectosigmoideal localisation, which could be confirmed by endoscopy.

CONCLUSION

The outcome of the few pediatric patients described in the literature was reviewed. Due to the lack of conclusive understanding of the nature of this extremely rare vascular disorder and the variable outcome described, a wait and see attitude should be assumed in cases of less clinical affection.

Histopathological parameters of Helicobacter pylori-associated gastritis in children and adolescents: comparison with findings in adults

BACKGROUND

The pathohistological features of Helicobacter pylori-associated gastritis in children and adolescents are less well understood than they are in adults. The aim of the study was to compare histological parameters of H. pylori-infected children with those of adults.

METHODS

The retrospective study compared histological features of 111 children (mean age 10.8 +/- 3.8). Three paediatric age groups were analysed and the findings were compared with those of 111 adults (mean age 64.2 +/- 12.1). Degree of chronicity and activity of inflammation, mucus depletion and regeneration of foveolar epithelium by regenerating epithelium and H. pylori colonization were scored in antral biopsies.

RESULTS

The histological parameters in children, i.e. degree of chronicity, activity of gastritis and the summed gastritis score, were not significantly different compared to those in adults. Replacement of foveolar epithelium by regenerating epithelium was significantly larger in adults compared to that of paediatric patients. The rate of low-grade mucus depletion and of the strongest degree of H. pylori colonization was higher in children than in adults. Children with antral nodularity had significantly higher histological score values.

CONCLUSION

The histological differences between paediatric patients and adults are focused on signs of chronic inflammation and regeneration. Our results imply that antral nodularity is an important sign of highest-grade gastritis, especially in young children.

Antibody response to dietary and autoantigens in G alpha i2-deficient mice

BACKGROUND

Mice with a targeted mutation in the G protein subunit G alpha i2 gene develop a colonic mucosal inflammation, with a highly activated B-cell response. We wanted to investigate whether this increased B-cell activity was directed against dietary antigens and/or various self tissues.

METHODS

The level of antibodies specific for dietary (gliadin, soya and fish meal) antigens was measured by ELISA. Reactivity against self antigens was measured by immunohistochemistry on cryo-sectioned mouse and rat tissue. Sera and intestinal lavages were analysed from G alpha i2-/- mice before and after development of colitis and in age-matched wild type litter mates.

RESULTS

Titres of antibodies against dietary antigens were significantly enhanced both in serum and in large intestinal lavages from G alpha i2-/- mice with ongoing colitis but not prior to disease, as compared to wild type mice. The autoreactivity to self tissues was significantly increased in G alpha i2-/- mice both before and after development of colitis as compared to litter mate control animals. Self tissue reactivity was directed not only against epithelial cells of the colon, small intestine and gastric glands, but also against smooth muscle cells, hepatocytes, bile duct cells, renal tubule and collecting tubule cells of the kidney. In analogy to human ulcerative colitis, autoantibodies against epithelial cells, bile duct epithelium and neutrophil granulocytes were found.

CONCLUSIONS

Earlier increase in levels of autoantibodies (before onset of colitis) than of food antibodies (after onset of colitis) suggests the latter response to be a secondary phenomenon to e.g. a destroyed barrier function.

A monoclonal antibody that recognizes a potential coeliac-toxic repetitive pentapeptide epitope in gliadins

OBJECTIVES

Antibodies that detect coeliac-toxic prolamins from wheat, barley and rye are important tools for controlling the diet of coeliac disease patients. Recently, a monoclonal antibody R5 that recognizes wheat gliadin, barley hordein and rye secalin equally was described. In this study, the epitope recognized by R5 was investigated.

METHODS

Both a phage-displayed heptapeptide library and overlapping peptides spanning the sequence of alpha- and gamma-type gliadins (pepscan) were screened for binding of R5.

RESULTS

Both techniques yielded comparable pentapeptide consensus sequences (phage display QXPW/FP; pepscan QQPFP). According to recent observations, this peptide stretch may be of key importance in the pathogenicity of coeliac disease. This sequence occurs repetitively in prolamins (in gamma- and omega-type prolamins more frequently than in alpha-type prolamins) together with several homologous peptide stretches, which are recognized less strongly.

CONCLUSIONS

R5 seems to be a good candidate for the specific detection of putative coeliac disease-active sequences in prolamins and thus represents a valuable tool for the quality control of gluten-free food.

Five- to 7-year-old children with Helicobacter pylori infection are smaller than Helicobacter-negative children: a cross-sectional population-based study of 3,315 children

OBJECTIVE

To test whether Helicobacter pylori-positive children are smaller and weigh less than H pylori-negative children.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

In 3,315 5-to 7-year-old preschool and school children, the putative influence of H pylori infection on growth was investigated. Standing height and weight were analyzed in relation to H pylori infection. The diagnosis of H pylori infection was established by 13C-urea-breath test.

RESULTS

The prevalence of H pylori infection in boys was 7.2% (95% confidence interval, 5.9-8.9; n = 1,550) and in girls was 6.1% (95% confidence interval, 4.9-7.3; n = 1,552) H pylori-positive children were smaller than noninfected children (117.6 +/- 5.5 cm vs. 118.9 +/- 5.7 cm; P < 0.01). Although H pylori-positive boys were 2.06 cm smaller than H pylori-negative boys (117.4 +/- 5.6 cm vs. 119.5 +/- 5.7 cm; P < 0.001), the difference in girls was not significant (117.9 +/- 5.3 cm vs. 118.4 +/- 5.7 cm). When standing height was adjusted for age, the found differences were more pronounced. Differences between the infected and noninfected children with regard to body weight were not significant (22.4 +/- 4.0 kg vs. 22.1 +/- 4.0 kg), nor was there a significant difference with regard to body-mass index. However, boys with H pylori infection had a lower weight than noninfected boys (21.6 +/- 3.3 kg vs. 22.6 +/- 4.0 kg; P < 0.01), but in girls, these differences were not observed (22.2 +/- 4.0 vs. 22.8 +/- 4.6 kg, respectively). When weight was adjusted for age, H pylori -positive children also had a lower weight than H pylori -negative children because of the lower weight of boys.

CONCLUSIONS

H pylori infection is associated with growth delay, growth retardation, or both in affected children.

Neurological disease-associated autoantibodies against an unknown protein encoded by a RES4-22 homologous gene

Screening a human small intestinal library with human serum yielded a clone which encoded a protein res4-22 the gene of which was highly homologous to a recently described gene located in the Huntington's disease locus. Autoantibodies against res4-22 (anti-res4-22), mainly of the immunoglobulin (Ig)A type, were detected in patients with neurological disorders at a higher frequency (18.4%) than in healthy blood donors (8.0%). In neurological patients with cerebral ischaemia anti-res4-22 was found significantly more often (47.4%) than in the total group of neurological patients. Anti-res4-22 positive sera showed significantly more frequently myelin staining in cerebellum and nerve sections than anti-res4-22 negative sera. Our findings demonstrate a new species of human autoantibodies against a newly described protein the function of which is still unknown.

Evidence for existence of coeliac disease autoantigens apart from tissue transglutaminase

BACKGROUND

The pathogenesis of coeliac disease (CD) and of dermatitis herpetiformis (DH) is strongly associated with production of autoantibodies, defined by indirect immunohistology. Recently, tissue transglutaminase (tTG) was identified as a prominent autoantigen. It would be important to investigate if further molecules apart from tTG are involved in autoimmunity.

METHODS

Tissue sections of human foetal intestine were used to compare the distribution of tTG with the autoantibody binding patterns of 14 sera samples from patients with CD or DH. Double label experiments were performed using monoclonal as well as polyclonal tTG antibodies (anti-tTG) and patient sera. The staining was investigated by using conventional light and confocal laser scanning microscopy.

RESULTS

Most autoantibody binding sites were matched by tTG. Further, the binding of autoantibodies could be inhibited by preincubation with monoclonal anti-tTG. However, in nine serum samples (64%) autoantibody staining suggested a few distinct binding sites apart from tTG. In three sera (21 %) autoantibody binding fibres were detected which definitely did not match monoclonal anti-tTG signals. Distinctly stained fibres were confirmed by applying polyclonal anti-tTG. This indicates the existence of autoantigenic epitopes not related to tTG.

B cell epitopes of gliadin

A phage displayed dodecapeptide library and synthetic octapeptides spanning the complete sequence of alpha- and gamma-type gliadin and overlapping in six amino acids (pepscan) were screened for binding to human gliadin antibodies (AGA). Phage display experiments led to four sequences recognized with significantly higher frequency by sera with raised IgA-AGA titres than by control sera. All these peptides contained the core sequence PEQ. Pepscan experiments revealed binding of AGA to five prominent regions: (i) QXQPFP (binding to IgG and IgA, X representing P, Q, and L); (ii) IPEQ (IgG) and WQIPEQ (IgA); (iii) FFQP (IgG) and QGXFQP (IgA, X representing F and S); (iv) PQQLPQ (IgG and IgA), all in alpha-type gliadin; and (v) QPQQPF (IgG and IgA) in gamma-type gliadin. In two of the sequences (QPQQPF and QQQPFP), substitution of Q by E resulting in QPEQPF and QEQPFP, respectively, increased significantly binding of AGA from sera of patients with biopsy-proven or suspected coeliac disease (CoD), all positive for endomysium antibodies (EmA). In contrast, binding of sera with high AGA titre from EmA-negative patients (CoD and dermatitis herpetiformis excluded) was not enhanced by this substitution. Thus, AGA directed against these modified epitopes can be regarded as specific for CoD. This is the first study demonstrating that deamidation of gliadin improves reactivity of AGA of CoD patients.