Western blotting is useful in the salivary diagnosis of Helicobacter pylori infection

BACKGROUND: The salivary diagnosis of Helicobacter pylori infection offers attractive possibilities for the epidemiological study of infection in children. Salivary enzyme linked immunosorbent assay (ELISA) is less reliable then serum ELISA, owing to variable transudation of immunoglobulin. In addition, children are more difficult to study because of lower specific serum antibody concentrations to H pylori. The performance of salivary western blotting in comparison with serum western blotting and serum ELISA was investigated in school children. SUBJECTS AND METHODS: Paired serum and saliva specimens were obtained from 669 [corrected] school children aged 9-11 in 10 British towns. All saliva and serum specimens were first analysed by ELISA; subsequently, western blotting of both specimens was performed on 31 and 34 specimens, respectively, to establish the criteria for positivity for western blotting. The remaining 121 specimens were then tested blindly and saliva was compared with the serum. RESULTS: The sensitivity and specificity of salivary ELISA in the 669 [corrected] specimens was 32 of 50 (64%) and 530 of 619 (86%) [corrected], respectively, when compared with serum ELISA. The western blotting validation was performed on 28 subjects with positive serum and positive salivary ELISA, 28 saliva positives with negative serum, 16 saliva negatives with positive serum, and 50 doubly negative subjects. Compared with serum western blots, the sensitivity and specificity of salivary western blots was 38 of 47 (81%) and 68 of 75 (91%), respectively. Using serum ELISA as the gold standard, the sensitivity and specificity were 32 of 44 (73%) and 72 of 78 (92%), respectively, the specificity being significantly higher than salivary ELISA (p < 0.001). CONCLUSION: Salivary western blotting for IgG is useful in the diagnosis of H pylori infection and is superior to ELISA. It also permits the identification of pathogenic strains.     

Alpha 1-antitrypsin deficiency and anti-proteinase 3 antibodies in anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis.

alpha 1-antitrypsin (alpha 1-AT) is a naturally occurring inhibitor of proteinase 3 (PR3) and elastase, two of the target antigens of anti-neutrophil cytoplasmic antibodies (ANCA). An increased incidence of alpha 1-AT phenotypes associated with dysfunctional alpha 1-AT or low serum levels has been reported in patients with anti-PR3 antibodies. We have studied the relationship between ANCA, and phenotypes and serum levels of alpha 1-AT. Phenotypes usually associated with a moderate or severe reduction in alpha 1-AT serum levels or in dysfunctional activity were found more often in individuals with anti-PR3 antibodies than in the general population: four of the 31 patients (13%) with anti-PR3 antibodies had phenotypes MZ (n = 2), S (n = 1) or Z (n = 1) (P < 0.05). However, the corresponding alpha 1-AT serum levels were normal (n = 3) or elevated (n = 1). None of the 31 sera with anti-PR3 antibodies had low levels of alpha 1-AT. No abnormal alpha 1-AT phenotype was demonstrated in seven patients with anti-elastase antibodies, despite a low level of alpha 1-AT in one serum. Anti-myeloperoxidase antibodies are common in patients with ANCA, but no abnormal phenotype or low serum alpha 1-AT level was demonstrated in any of 29 sera containing these antibodies. Finally anti-glomerular basement membrane (GBM) antibodies occur occasionally in patients with ANCA-associated diseases, but again none of 10 sera had an abnormal alpha 1-AT phenotype or low serum level. ANCA were not demonstrated by indirect immunofluorescence in any serum from 73 patients with abnormal alpha 1-AT phenotypes. These results confirm that patients with anti-PR3 antibodies often have alpha 1-AT phenotypes that are usually associated with low serum levels of alpha 1-AT or with dysfunctional protein. Nevertheless, the incidence of anti-PR3 antibodies in patients with abnormal alpha 1-AT phenotypes is very low. This probably reflects the rarity of Wegener's granulomatosis, the major disease associated with anti-PR3 antibodies, and the relative frequency of abnormal alpha 1-AT phenotypes. The mechanism for the development of anti-PR3 antibodies in patients with abnormal alpha 1-AT phenotypes is not clear, but may relate to the increased propensity of unbound and uninhibited PR3 to stimulate autoantibody production.     

Sedative but not anxiolytic properties of benzodiazepines are mediated by the GABA(A) receptor alpha1 subtype

Inhibitory neurotransmission in the brain is largely mediated by GABA(A) receptors. Potentiation of GABA receptor activation through an allosteric benzodiazepine (BZ) site produces the sedative, anxiolytic, muscle relaxant, anticonvulsant and cognition-impairing effects of clinically used BZs such as diazepam. We created genetically modified mice (alpha1 H101R) with a diazepam-insensitive alpha1 subtype and a selective BZ site ligand, L-838,417, to explore GABA(A) receptor subtypes mediating specific physiological effects. These two complimentary approaches revealed that the alpha1 subtype mediated the sedative, but not the anxiolytic effects of benzodiazepines. This finding suggests ways to improve anxiolytics and to develop drugs for other neurological disorders based on their specificity for GABA(A) receptor subtypes in distinct neuronal circuits.     

Vibriophage VcA-3 as an epidemic strain marker for the U.S. Gulf Coast Vibrio cholerae O1 clone.

Toxigenic and nontoxigenic Vibrio cholerae O1, El Tor biotype strains, which are endemic to the U.S. Gulf Coast, can be lysogenic for bacteriophage VcA-3. To evaluate the presence of VcA-3 as an indicator of toxigenicity and as an epidemic strain marker, phage production and the presence of phage and cholera toxin genes were assayed in 98 strains of V. cholerae O1 (35 U.S. and 63 foreign strains). By using a HindIII chromosomal digest for Southern blot analysis, 39 of the study strains hybridized with the VcA-3 probe in 10 banding patterns. The 15 toxigenic and 6 of the 20 nontoxigenic U.S. isolates gave four VcA-3-related patterns. Among the foreign isolates, 12 of 12 toxigenic classical biotype strains, 1 of 43 toxigenic El Tor biotype strains, and 3 of 8 nontoxigenic atypical strains gave six patterns that were clearly distinct from that of VcA-3. Compared with Southern blot analysis, the phage production assay had a sensitivity of 1.0 and a specificity of 0.48, while the colony hybridization assay had a sensitivity of 1.0 and a specificity of 0.77 for identification of VcA-3. Neither assay reliably identified the toxigenic Gulf Coast clone. The presence of VcA-3, as defined by Southern blot analysis, always separated toxigenic U.S. from foreign isolates and often from nontoxigenic U.S. isolates of V. cholerae O1.     

Sequences of two kinetoplast minicircle DNAs of Trypanosoma (Nannomonas) congolense

Random minicircle DNA molecules were released from isolated kinetoplast network DNA of Trypanosoma congolense by BamHI digestion and cloned into plasmid pUC19. The sequences of two cloned minicircles (958 bp and 964 bp) were determined. Both minicircles contain the 13 bp sequence, 5'-GGGGTTGGTGTAA-3', thought to be the replication origin of minicircles in other trypanosomatids. The two minicircles have extensive homology in the 120 bp preceeding, and the 20 bp following, this 13-mer but only scattered homology elsewhere. Both possess tandem repeats downstream of the 13-mer. Comparison of these minicircles with minicircle sequences from other trypanosomatids reveals that they have the same general sequence organization as the others although only the 13-mer and its flanking regions are homologous.     

Curing efficiency and ocular hazards of dental photopolymerization sources

The spectral distributions of a range of dental photocuring sources were measured at the exit window and at a distance of 10 cm. The former enabled the evaluation of a newly proposed photocuring efficiency index which correlates well with the depth of cure of the photopolymerized resins, thus providing a basis for the comparison of different photocuring sources. The spectral irradiante of the sources obeyed the inversesquare law, allowing a comparison with the ACGIH threshold limit values. According to these criteria, no ocular hazard is posed to the patient or clinician by u.v.-A or u.v.-B radiation nor to the patient by the visible light when momentarily exposed to the sources. Similarly the ACGIH criterion indicates that the clinician does not risk chorioretinal injury provided the exposure is restricted to less than 140 s in a 3 h period.     

Structure and properties of methacrylate based dental restorative materials

The chemistry and structure of the dimethacrylate resins and the nature of the filler systems in dental composite resins are reviewed in relation to their influence on the setting behaviour, dimensional stability, aesthetics, fracture behaviour and adhesive potential. It is clear that a deeper understanding of the structure of the polymeric matrix and the mechanism of clinical wear is required. As a result of ongoing research in this area and with the development of dentine adhesives, the future prospects of composite resins are encouraging.     

Effect of articular disease and total knee arthroplasty on knee joint-position sense

Joint proprioception in the human knee has been studied using two previously described tests. Threshold of detection of slow, constant, passive motion and ability to reproduce angles to which the knee was passively placed were accurately measured. A group of postoperative total knee arthroplasty (TKA) patients were examined. All patients also had documented articular disease in the unoperated knee. Results were compared to age-matched controls. In addition, a young control group was studied for comparison to both groups. A significant difference was seen between the young control group and the older control group in both tests performed. Age-matched controls and the postoperative patients demonstrated an even greater difference. There was, however, no difference between the operated and unoperated knee among the TKA patients. It is concluded that joint proprioception declines to some degree with normal aging. A more marked decline is associated with degenerative joint disease. Total joint replacement, however, did not lead to a further decrease in sensation.     

Development of Na+-dependent hexose transport in a cultured line of porcine kidney cells

LLC-PK1 cells in culture do not concentrate alpha-methylglucoside (alpha-meG) during their early growth phase but develop the capacity to concentrate this hexose as the growth rate decreases in confluent cultures. The concentrating ability is dependent on the Na+ electrochemical gradient and is inhibited by phlorizin with KI,0.5 approximately 0.2 microM. The development of the concentrative capacity can be accelerated by the Friend cell inducer hexamethylene bisacetamide (HMBA) and by the phosphodiesterase inhibitors dibutyryl cAMP, theophylline, and 1-methyl-3-isobutylxanthine (MIX). In cultures treated with any of these differentiation-accelerating chemicals, the development of alpha-meG concentrating capacity is severely inhibited by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) but not by inactive (in tumor promotion) analogs of TPA. In all cases, an early event in the development of alpha-meG accumulating capacity is an elevated intracellular cAMP concentration; however the results suggest that this increase in cAMP may be necessary but not sufficient to induce the differentiated hexose-accumulating capacity.     

Longitudinal studies on the egg drop syndrome 1976 (eds-76) in the fowl following experimental infection at 1-day-old

Following oral infection of 1-day-old chicks with egg drop syndrome - 1976 (EDS-76) virus (strain D61) lateral transmission of the virus was demonstrated throughout the rearing period. At point of lay, pullets previously infected at 1-day-old responded to EDS-76 inactivated vaccine given intramuscularly with a pronounced rise in haemagglutination inhibition antibody titre, but failed to respond to oral challenge with live virus. Egg production and shell quality were not affected following EDS-76 infection at 1-day-old, but egg weight was reduced and internal egg quality adversely affected.