Use caution with serologic testing for Helicobacter pylori infection in children

Commercial serologic assays accurately detect adult Helicobacter pylori infection. Their use in children remains controversial. An ELISA to detect H. pylori IgG in children was developed and compared with three commercial assays. ELISA standardization was done with sera from all ages and validation was done with another cohort of sera with known H. pylori status. Three commercial serologic assays were subsequently compared against this pediatric ELISA at independent sites, at which 142 pediatric serum samples from different countries were evaluated. The pediatric ELISA was 91.4% sensitive. Assay 3 demonstrated a sensitivity of 78%. Less sensitivity was observed for assay 1 (70%) and assay 2 (63%). Accuracy of commercial assays was greatly reduced when sera from developing countries and younger ages were evaluated. Results of serologic tests used to diagnose H. pylori should be interpreted with caution when evaluating children with abdominal pain. Accurate serologic assays in children may be more important for epidemiologic research than for clinical decision making.     

Free and total bupivacaine plasma concentrations after continuous epidural anaesthesia in infants and children

OBJECTIVES: The aim of this study was to elucidate the prevalence of Helicobacter pylori and its distribution in order to clarify the frequency of H. pylori infection and the most appropriate site of endoscopic biopsy for studies of H. pylori infection associated with different gastric diseases. DESIGNS AND METHODS: Swiss role mucosal strips from 275 resected stomachs, which included the greater curvature, anterior wall and lesser curvature of the antrum, incisura and corpus, were stained with haematoxylin-eosin and H. pylori antibody. RESULTS: The prevalence of H. pylori infection was 97% in duodenal ulcers, 98% in gastric ulcers, 98% in intestinal-type carcinomas and 99% in diffuse-type carcinomas. H. pylori was present at a rate of 100% in any site in cases of duodenal ulcer, but was diffusely distributed in the antrum and patchily distributed in the corpus. The detection rate of H. pylori was 50-100% in gastric ulcers, 30-100% in intestinal-type adenocarcinomas and 63-100% in diffuse-type adenocarcinomas depending on the site of the stomach examined. CONCLUSIONS: The prevalence of H. pylori infection was very high in peptic ulcers of the duodenum and stomach and gastric carcinomas of Japanese patients. Biopsy specimens for evaluation of H. pylori infection should be taken routinely from both the greater curvature of the antrum and corpus. Immunohistochemical staining should be used to assay for H. pylori when few organisms are present or eradication therapy has been used.     

A review of esthetic alternatives for the restoration of anterior teeth

Helicobacter pylori infection is an important cause of peptic ulcer disease and chronic gastritis. Infection with this bacterium stimulates the production of immunoglobulin (Ig) G antibody. Salivary IgG antibody tests to detect H pylori infection offer a convenient and noninvasive method of diagnosis. To evaluate an IgG salivary antibody kit, saliva was collected from 157 out-patients with dyspepsia referred for endoscopy to a tertiary centre. A salivary IgG ELISA antibody assay was performed using the Helisal Helicobacter pylori (IgG) assay kit, and at least four gastric biopsies were obtained. H pylori infection was confirmed by demonstration of the organism on Warthin-Starry silver stain (sensitivity 85%, specificity 55%). The prevalence of infection with H pylori was 30%. When the analysis was redone, excluding those treated with eradication therapy, the results were similar (sensitivity 86%, specificity 58%). The positive predictive value of the assay was 45% and the negative predictive value was 90%. Despite the ease of sampling, the assay used has limited diagnostic utility, lacking the predictive value to indicate which patients referred with dyspeptic symptoms to a tertiary care setting are infected with H pylori.     

Search for putative virulence factors of Helicobacter pylori: the low-molecular-weight (33-35 K) antigen

Early studies suggested that two Helicobacter pylori proteins, CagA and VacA, were virulence factors. Support for that hypothesis has been undermined by geographic differences in prevalence of these antigens. To identify other possible putative virulence factors by establishing a relationship between antigens and different H. pylori diseases, two commercial available immunoblot assay kits, HelicoBlot 2.0 (Genelabs Diagnostics, Singapore) and RIDA Blot Helicobacter (R-Biopharm GmbH, Darmstadt, Germany), were used to investigate the prevalence of various specific antigen seropositivity in 80 H. pylori-infected Japanese (20 each with gastritis, duodenal ulcer, gastric ulcer, or gastric cancer). The production of interleukin-8 (IL-8) in biopsy specimens was also measured by enzyme-linked immunosorbent assay (ELISA). Both assays had 100% sensitivity; specificity was 90% for HB2.0 and 80% for RIDA-BH. With the exception of the 33-35 K antigen, there was no relationship between antigens, endoscopic diagnoses, histological findings, or mucosal IL-8 levels. The 33-35 K antigen was present in 97.5% (39 of 40) patients with gastric or duodenal ulcer compared to 70% (14 of 20) those with chronic gastritis (P < 0.006). The mean IL-8 levels in the corpus was significantly higher in those with antibody to the 33-35 K antigen compared to those without (105.4+/-22 pg/mg vs 10.2+/-8.8 pg/mg) (P=0.015). There was no relationship between other antigens including CagA and production of IL-8. In conclusion, the low-molecular-weight 33-35 K antigen may play an important role in the pathogenesis of H. pylori-related disease.     

Analysis of common antigen of flagella in Bacillus cereus and Bacillus thuringiensis

Flagellar antigen of Bacillus cereus H.1 was purified and tested for serodiagnostic antigen by ELISA. The antibody against the flagellar antigen of B. cereus H.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of B. cereus. This common flagellar antigen of B. cereus was found to be due to 61-kDa protein by SDS-PAGE and immunoblot assay. Monoclonal antibody H15A5 against common antigenic epitope of B. cereus also reacted with flagellar antigens of 21 strains of Bacillus thuringiensis by ELISA. This monoclonal antibody reacted with the 61-kDa protein of the flagella of B. cereus H.1 and H.2 and B. thuringiensis Kurstaki HD1, Alesti and Aizawai juroi by immunoblot analysis. These results indicated that the common antigenic epitope of the 61-kDa protein existed in the flagella both of B. cereus and B. thuringiensis.     

Evaluation of eight commercial kits for Helicobacter pylori IgG antibody detection

Eight commercial kits and an in-house ELISA for detection of IgG antibodies against Helicobacter pylori were evaluated for their use in diagnosis of H. pylori infection and in epidemiological research: Helico-GTM (Porton-Cambridge), G. A. P. test (Bio-Rad), H. pylori antibodies ELISA (Biometra), Anti-H. pylori IgG EIA (Roche), 2nd generation H. pylori EIA (Roche), Anti-H. pylori MTP-assay (Roche), Pylori stat test kit (Whittaker), Pyloriset latex agglutination kit (Orion), and the in-house ELISA based on heat-stable antigens. Fifty-four patients with dyspepsia (31 H. pylori positive by culture or microscopy) and 68 asymptomatic persons were tested. Sensitivities for the eight kits were 71%, 77%, 90%, 84%, 87%, 94%, 90%, 87%, and 87%, specificities were 74%, 65%, 74%, 74%, 83%, 83%, 70%, 65%, and 65%, respectively. For epidemiological use the estimated seroprevalence varied within approximately 15% in all age groups. Sensitivities and specificities obtained in different studies reveal as great differences in the results with the same kit as between results obtained with different kits in the same study. Kits with the highest sensitivities tend to be the same in all studies. It is therefore more important to test a kit in the population to which it is to be applied than to choose a specific kit.     

Salivary-specific immunoglobulin G in the diagnosis of Helicobacter pylori infection in dyspeptic patients

OBJECTIVES: Helicobacter pylori infection is arguably the most common chronic bacterial infection in humans. The high prevalence and the association with peptic ulceration and gastric cancer indicate that simple, noninvasive methods for diagnosis of the infection are needed. In this study, the accuracy of salivary diagnosis for H. pylori infection was assessed. METHODS: Saliva and serum samples of 152 dyspeptic patients were tested for H. pylori IgG and IgA by an in-house ELISA. All patients underwent gastroscopy with biopsy. RESULTS: One hundred thirty-one patients (86%) were found to be H. pylori positive on histology. Duodenal ulcer was found in 67 patients; 85 had no macroscopic lesion. Salivary and serum H. pylori IgG as well as serum H. pylori IgA titers were significantly higher in H. pylori-positive than in H. pylori-negative patients. The sensitivity and specificity of salivary H. pylori IgG were 82% and 71%, respectively; the positive and negative predictive values were 95% and 40%, respectively; and the accuracy 81%. The corresponding figures for serum H. pylori IgG were 97% and 91%; 98% and 83%; and 96%. Those for serum H. pylori IgA were 80% and 52%; 91% and 30%; and 76%. The sensitivity of salivary H. pylori IgG in detecting duodenal ulcer was 83% (56/67) that of serum H. pylori IgG was 97% (65/67) (odds ratio = 0.15; confidence interval = 0.02-0.8; p = 0.02). CONCLUSIONS: Salivary H. pylori IgG was a fairly sensitive and accurate indicator of gastric H. pylori colonization, with a high positive predictive value in our population. Data, however, suggest that salivary H. pylori IgG measurements do not compare favorably with serology.     

Helicobacter pylori CagA antigen antibodies

BACKGROUND: CagA antigen of Helicobacter pylori is highly immunogenic in humans. There is an increasing evidence that infection with CagA-positive strains is related to the development of peptic ulcer disease, atrophic gastritis, or gastric cancer. The aim of our study was to assess seropositivity to CagA in a group of 95 clinically symptomatic adults who underwent gastroduodenoscopy and to correlate results to their disease characteristics. METHODS AND RESULTS: Serum immunoglobulin G antibodies to CagA detected by ELISA kit (Helicobacter p120, Viva Diagnostika, Germany) were compared to standard IgG specific antibodies against a pool of H. pylori antigens Synelisa Pin plate, ELIAS, Germany). Immunoglobulin G antibodies to CagA were present in 5/31 (16%) serum samples from H. pylori negative persons and 10/28 (36%) serum samples from H. pylori positive patients without peptic ulcer disease compared with 8/11 (73%) H. pylori positive patients with peptic ulcer disease in the past, 11/13 (85%) H. pylori positive patients with duodenal ulcers or duodenitis and 4/5 (80%) H. pylori positive (1/7, 14% H. pylori negative) serum samples from patients with gastric resection for peptic ulcers in the past. Serum levels of antibodies to CagA in the groups of patients with peptic ulcer disease in the past, with present duodenal ulcers of duodenitis and in H. pylori infected patients with gastric resection were significantly higher then those of H. pylori infected patients without peptic ulcer disease (P < 0.05). On the other hand, there was no significant difference in the presence of the specific antibodies against at pool of H. pylori antigens between these four groups. CONCLUSIONS: These data suggest that serologic response to the CagA antigen is more prevalent in H. pylori positive persons with present or past peptic ulceration than among infected persons without peptic ulcer disease. The presence of antibodies to CagA in H. pylori positive persons may be useful for the identification of patients with higher risk or more severe disease.     

Detection of colorectal cancer cells in peripheral blood by reverse-transcriptase polymerase chain reaction for cytokeratin 20

In this study we have determined systemic and local antibody responses against different Helicobacter pylori antigens in H. pylori-infected and noninfected subjects. In addition, we studied whether differences in antibody responses between patients with duodenal ulcers and asymptomatic H. pylori carriers might explain the different outcomes of infection. Sera and in most instances gastric aspirates were collected from 19 duodenal ulcer patients, 15 asymptomatic H. pylori carriers, and 20 noninfected subjects and assayed for specific antibodies against different H. pylori antigens, i.e., whole membrane proteins (MP), lipopolysaccharides, flagellin, urease, the neuraminyllactose binding hemagglutinin HpaA, and a 26-kDa protein, by enzyme-linked immunosorbent assay. The H. pylori-infected subjects had significantly higher antibody titers against MP, flagellin, and urease in both sera and gastric aspirates compared with the noninfected subjects. Furthermore, the antibody titers against HpaA were significantly elevated in sera but not in gastric aspirates from the infected subjects. However, no differences in antibody titers against any of the tested antigens could be detected between the duodenal ulcer patients and the asymptomatic H. pylori carriers, either in sera or in gastric aspirates.     

Orthopedic and interventional applications at low field MRI with horizontally open configuration. A review

Two monoclonal antibodies (MAbs), designated as H9 (IgG2a) and H20 (IgM), directed against heat-shock protein 60 (HSP60) of Helicobacter pylori strain TK1029 were established. Affinity-purified antigens cross-reacted in immunoblots with MAb H9 and MAb H20 respectively. These antigens also reacted with the 3C8 MAb previously established in this laboratory, which recognised Yersinia enterocolitica HSP60. By amino-acid sequence analysis, the N-terminal amino-acid sequence of the protein recognised by both H9 and H20 MAbs was confirmed as the amino-acid sequence of H. pylori HSP60 reported previously. Both MAbs reacted with nine strains of H. pylori in enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. In addition, MAb H9 reacted with extracts of other bacteria including H. mustelae, Pseudomonas aeruginosa, Vibrio cholerae, Serratia marcescens, Proteus mirabilis, Escherichia coli and Shigella sonnei. In contrast, MAb H20 reacted only with strains H. pylori. These results suggest that both the species-specific epitope recognised by MAb H20 and the common epitope recognised by MAb H9 exist on HSP60 of the bacterial cell. Both MAbs also reacted with the 60-kDa protein in the lysate of human gastric carcinoma (MKN45) cells. It was shown by immunohistochemical staining that gastric epithelial cells of four out of six biopsy specimens examined stained positively with MAb H20. These results suggest that there is a common epitope in H. pylori HSP60 and human gastric epithelial cells.     

Regulation of ciprofloxacin uptake in human promyelocytic leukemia cells and polymorphonuclear leukocytes

BACKGROUND: It has recently been shown that humoral antigastric autoreactivities occur in a substantial number of Helicobacter pylori infected patients. AIMS: To analyse the relevance of such antigastric autoantibodies for histological and serological parameters of the infection as well as for the clinical course. METHODS: Gastric biopsy samples and sera from 126 patients with upper abdominal complaints were investigated for evidence of H pylori infection using histology and serology. Autoantibodies against epitopes in human gastric mucosa were detected by immunohistochemical techniques. Histological and clinical findings of all patients were then correlated with the detection of antigastric autoantibodies. RESULTS: H pylori infection was significantly associated with antigastric autoantibodies reactive with the luminal membrane of the foveolar epithelium and with canalicular structures within parietal cells. The presence of the latter autoantibodies was significantly correlated with the severity of body gastritis, gastric mucosa atrophy, elevated fasting gastrin concentrations, and a decreased ratio of serum pepsinogen I:II. Furthermore the presence of anticanalicular autoantibodies was associated with a greater than twofold reduced prevalence for duodenal ulcer. CONCLUSION: The data indicate that antigastric autoantibodies play a role in the pathogenesis and outcome of H pylori gastritis, in particular in the development of gastric mucosal atrophy.     

Isolation and characterization of Helicobacter pylori strains from peptic ulcer patients in Dhaka, Bangladesh

To study the association of Helicobacter pylori with peptic ulcer and the associated histopathological changes, to characterize the isolated strains in terms of their protein profile, 83 peptic ulcer cases were studied. A high association of H pylori with peptic ulcer (duodenal ulcer 77%, gastric ulcer 75%) and gastritis (74%) was observed. Age and smoking did not have any relationship with H pylori infection. The infection was predominantly associated with the 'quiescent' form of chronic gastritis. Comparative sodium dodecyl sulfate polyacrylamide gel electrophoresis of whole cell extracts of the local isolates and a reference strain from Australia showed a general homogeneity between the strains with obvious interstrain differences. However, the difference between the local isolates and the reference strain was more marked. Significant association of H. pylori with peptic ulcer along with strain variations were observed.     

Rapid recurrence of Helicobacter pylori infection in Peruvian patients after successful eradication. Gastrointestinal Physiology Working Group of the Universidad Peruana Cayetano Heredia and The Johns Hopkins University

Helicobacter pylori is associated with gastritis, peptic ulcer disease, and gastric cancer. Since gastric cancer is common in Peru, eradication of H. pylori may help to reduce the occurrence of gastric cancer. This study involved three randomized trials to determine the efficacy of four different triple-drug therapy regimens. The most successful regimen was furazolidone combined with bismuth subsalicylate and amoxicillin, which eradicated infection in 82% of patients. Patients successfully treated were followed every 2-3 months to determine the recurrence rate of H. pylori infection. Of 105 patients with H. pylori eradication documented by pathology and culture, 52% (55) returned for follow-up endoscopy, and in 73% (40) of these 55 the infection recurred during the 8-month follow-up period. Thirty-five patients from whom H. pylori was eradicated and who were tested for antibodies to H. pylori remained consistently seropositive. Rapid recurrence of H. pylori infection after successful eradication suggests that measures other than antimicrobial therapy are needed to fight H. pylori in developing countries.     

Role of Helicobacter pylori in reflux esophagitis

It is now widely accepted that peptic ulcer disease (PUD) is a result of chronic infection of Helicobacter pylori (H. pylori). Thus, treatment of PUD should be aimed toward eradication of H. pylori with antibiotics. One the other hand, recent study from England suggested that eradication of H. pylori may provoke development of reflux esophagitis in duodenal ulcer patients. Despite duodenall ulcer patients with concomitant esophagitis is a specific type of esophagitis, it is important to recognize the development of reflux esophagitis after cure of H. pylori infection. Whether the development of reflux esophagitis is occurred in other H. pylori-related disease such as gastric ulcer remains to be studied.     

The effect of H. pylori in perforation of duodenal ulcer

BACKGROUND/AIMS: H. pylori has been described as an opportunistic pathogen attracted by changes in the gastric mucosa caused by inflammation and ulceration. However, the role of H. pylori infection in the perforation of duodenal ulcers has not yet been clearly determined. The aim of this study was to assess the prevalence of H. pylori infection in patients undergoing laparotomy for repair of a perforated duodenal ulcer. METHODOLOGY: Patients who underwent surgery for a perforated duodenal ulcer in our Surgical Unit between January 1994 and July 1996 were included in this study. The study population consisted of eighteen patients with a mean age of 32.7 (21-48) years. All of the patients were male. Patients with chronic duodenal ulcer perforation and with no contraindications for definitive surgery, such as peritonitis, shock (blood pressure <90 mm Hg), age >60 years, or more than a 12-hour elapse from the time of perforation, were treated by bilateral truncal vagotomy and Weinberg pyloroplasty. The ulcer was excised with the pyloric ring. The cut was then extented by about 2 cm on both the gastric and duodenal sides. Two biopsies were taken from the antral mucosa by endoscopic biopsy forceps. The defect was closed transversely. The ulcer specimen and the antral biopsies were fixed separately in 10% formalin solution and sent to the department of Histopathology. The specimens were stained with Hematoxylin-Eosin and examined for H. pylori . Sections of the ulcer specimen were especially investigated for the presence of H. pylori through all layers of the ulcer. RESULTS: H. pylori was found in the antral biopsies of 16 patients (88.8%). In seven of the ulcer specimens (38.8%), H. pylori was present in the mucosa and also extended through the wall of the ulcer. H. pylori was positive in the antral biopsies of all patients with H. pylori present in the ulcer wall. CONCLUSIONS: In our study, H. pylori was present at a high ratio in the antral biopsies of patients with duodenal ulcer perforation. The presence of H. pylori throughout the ulcer wall to a considerable extent emphasizes the fact that eradication of H. pylori is important in the treatment of perforated duodenal ulcer.     

Serum antibodies against Helicobacter pylori proteins VacA and CagA are associated with increased risk for gastric adenocarcinoma

Infection with Helicobacter pylori is associated with the development of gastric cancer. To study whether the infection with H. pylori strains expressing the vacuolating cytotoxin (VacA) and/or the cytotoxin-associated protein (CagA) is associated with an increased risk of developing gastric adenocarcinoma, sera of 90 patients with gastric cancer and 90 matched controls with cardiovascular diseases were investigated for the presence of antibodies to VacA and CagA by immunoblot. Although no significant difference in the overall H. pylori seropositivity was found between cancer patients and controls, antibodies against VacA or CagA were significantly more frequent in cancer patients than in control subjects. Seventy-five (97.4%) of 77 H. pylori-positive patients in the cancer group, but only 60 (84.5%) of 71 H pylori-positive control patients had antibodies against either VacA or CagA (chi 2 = 6.63; relative risk, 2.00; 95% confidence interval, 1.18-3.39; P = 0.01). The presence of antibodies against VacA or CagA alone was also associated with an increased cancer risk (92.2% vs 80.3%; chi 2 = 5.30; relative risk, 1.74; 95% confidence interval, 1.08-2.78; P = 0.021, for VacA; and 87.0% vs 74.6%; chi 2 = 4.90; relative risk, 1.61; 95% confidence interval, 1.06-2.45; P = 0.037, for CagA). The relative risk for gastric cancer was mainly elevated in patients under 65 years, but not in patients at or over 65 years. There is evidence that infection with VacA- or CagA-producing H. pylori strains increases the risk of developing gastric cancer, especially in younger patients.     

Somatostatin receptor imaging of olfactory neuroblastoma

BACKGROUND: Cure of H. pylori infection in peptic ulcer patients significantly reduces the risk of ulcer recurrence. Since data on the rate of H. pylori reinfection in patients undergoing successful anti-H. pylori therapy are sparse, this study was conducted with the aim of determining the H. pylori reinfection rate in peptic ulcer patients receiving antibacterial treatment to heal their ulcer and cure H. pylori infection. METHODS: A total of 217 patients with H. pylori-associated duodenal or gastric ulcer were followed up after treatment with various antibacterial regimens resulting in histologically documented cure of H. pylori infection. Endoscopic and histological examinations were performed 4 weeks after completion of treatment and after 1, 2 and 5 years, or whenever dyspeptic symptoms occurred. To assess the H. pylori status two antral and two corpus biopsies were obtained for histological examination. RESULTS: Out of 217 patients with initially cured H. pylori infection 175 were available for endoscopic follow-up. At the time of analysis, 44 patients were re-examined after 1 year, 113 patients after 2 years and 18 patients after 5 years, giving a total of 360 patient years of follow-up. The mean duration of follow-up was 24.7 months. H. pylori reinfection was confirmed histologically in eight patients, three of whom becoming H. pylori-positive again within the first year of follow-up. Six of the eight patients with H. pylori reinfection also suffered an ulcer relapse. Eight cases of reinfection in 360 patient years represents an overall reinfection rate of 2.2%. Within the first 2 years of follow-up the reinfection rate was 0.8% per year. CONCLUSION: Our data suggest that H. pylori reinfection is rare in peptic ulcer patients receiving successful anti-H. pylori therapy. H. pylori reinfection frequently coincides with ulcer recurrence. Cure of H. pylori infection results in cure of peptic ulcer disease, provided H. pylori reinfection does not occur.     

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.     

Salivary immunoglobulin G assay to diagnose Helicobacter pylori infection in children

An in-house enzyme-linked immunosorbent assay (ELISA) for measurement of Helicobacter pylori-specific immunoglobulin G (IgG) and IgA in saliva was evaluated by comparison with histopathologic (Giemsa staining) and biochemical (urease quick test) examination of gastric biopsy specimens obtained from 112 children referred for diagnostic gastroscopy. Serum H. pylori IgG was also measured in a subgroup of 50 children by the same ELISA. Salivary H. pylori IgG levels were significantly higher in H. pylori-positive (n = 57) than in H. pylori-negative (n = 55) children (P < 0.001). The sensitivity and specificity of the salivary IgG test were 93 and 82%, respectively; the positive and negative predictive values were 84 and 92%, respectively; and the accuracy was 87.5%. Salivary H. pylori IgA did not distinguish H. pylori-positive from H. pylori-negative children. The performance of serum H. pylori IgG was slightly (3 to 6%) better than that of salivary H. pylori IgG. The salivary IgG test can be considered a useful tool for the screening of H. pylori infection in children.     

Evaluation of a new chromogenic substrate assay for the measurement of the prothrombin time

Since the ingestion studies by Marshall and Morris, Helicobacter pylori has been known to cause both acute and chronic infection in the human stomach activating both the cellular and the humoral immune system. It is of little or no value to evaluate the causative relationship of an infectious agent using Koch's criteria. The more recent criteria for causative relationships used in the science of epidemiology are more useful. These criteria include: (i) the characteristic of the association which is fulfilled for most cases of both duodenal and gastric ulcer; (ii) the temporal relationship which is fulfilled for duodenal ulcer and has not been investigated for gastric ulcer; (iii) the biological gradient which has been fulfilled for duodenal ulcer in a few studies but not investigated for gastric ulcer; (iv) the biological plausibility which is easily fulfilled for both duodenal and gastric ulcer; (v) the effect of an intervention which has been fulfilled for duodenal ulcer and in a few studies for gastric ulcer; and (vi) the coherence of these data with what is known about the disease which is fulfilled for both duodenal and gastric ulcer. Even though there is no need for all criteria to be fulfilled, further studies are necessary to confirm the temporal relationship between H. pylori and peptic ulcer, and the biological gradient of H. pylori in relation to the gastric ulcer. Even so, there is a strong indication that most of the peptic ulcers, apart from those caused by non-steroid anti-inflammatory drugs and Zollinger-Ellison-like syndromes, are caused by H. pylori infection.