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Biomedical subjects

Yaron Niv

Publications and source records attributed to Yaron Niv.

At least 55 records · Page 3Linked to original sources
PubMed2003

Survey of the opinions, knowledge and practices of surgeons and internists regarding Helicobacter pylori test-and-treat policy.

BACKGROUND: Helicobacter pylori infection is highly prevalent and may cause disease in 10% to 15% of infected individuals: duodenal and gastric ulcer, gastric cancer and gastric lymphoma. Guidelines for a test-and-treat policy have been published by the European H. pylori working group in Maastricht. GOALS: To assess the current approach to H. pylori-related diseases, indications for testing and eradication therapy, among internists and surgeons of a University affiliated medical center. STUDY: A 15-items questionnaire was formulated according to the Maastricht II test-and-treat recommendation and distributed among the physicians of 6 internal medicine departments and the department of surgery. The questionnaires were completed anonymously at the department's staff meeting, under the supervision of the head of the department. All questions required a yes/no answer; the maximum possible score was 15. The relative ratio (RR) of correct answers was calculated for every question and by subgroups as follows: all participants, internists, surgeons, experts and residents in internal medicine and surgery. RESULTS: The response rate was 68% (55 out of 80 physicians). Total score for all participants was 10.9 (RR = 0.73), significantly lower than the maximum score of 15 (RR = 1.00). The internists had significantly higher average score than the surgeons for 2 questions: causative agent in gastric cancer (p = 0.003) or gastric lymphoma (p = 0.003), 1 question about triple therapy, PPI, penicillin and azythromycin being not recommended (p = 0.022), and for 1 question of test-and-treat policy: should this strategy apply to family members of gastric cancer patients (p = 0.045). Only 56% of the internists and 21% of surgeons knew what MALToma is, and the correlation with H. pylori infection. CONCLUSION: Knowledge of Surgeons and Internists regarding infection and correlation with diseases or test and treat policy should be improved.

Academic Medical Centers↗
PubMed2003

Family history of gastric cancer: should we test and treat for Helicobacter pylori?

A close link has been established between infection and gastric cancer. In this article, we suggest that using a risk stratification technique (like that for colorectal cancer), the high-risk group of first-degree relatives of patients with gastric cancer can be separated out for testing and treatment. This would be more manageable and more cost-effective than screening the whole population, in which the mortality from distal gastric cancer has declined concomitant with the eradication of infection. Support for the feasibility of this approach is derived from studies showing that the family is the core unit of transmission and that childhood colonization, especially with a virulent strain, is apparently a major risk factor for disease progression to the neoplastic stage. When there is a case of gastric cancer in the family, first-degree relatives, who might be infected by a bacterium with an identical genetic fingerprint, are at higher risk than normal for developing gastric cancer. Furthermore, genetic and epidemiologic studies based on the Correa model have shown that both primary and secondary prevention of gastric cancer is possible. Calculations done in high-risk populations, such as Japanese-Americans, confirm the savings in cost and the safety of the test-and-treat strategy. Considering that eradication should be done as early as possible, at a point in the cascade when the changes are still reversible, and that gastric cancer is associated with a high mortality rate, we suggest that this strategy be applied to this high-risk population.

Helicobacter Infections↗
PubMed2003

13C-urea breath test, referral patterns, and results in children.

BACKGROUND: The family is the core unit for Helicobacter pylori (Hp) infection. In most instances, Hp colonization occurs in early childhood, and correlates with socioeconomic parameters. Helicobacter pylori infection is highly prevalent in many countries, and may cause chronic gastritis and peptic ulcer in adults and in children. Gastritis induced by Hp may be associated with recurrent abdominal pain in children, and eradication of the bacterium may improve the clinical symptoms. AIM The primary aim of this study is to characterize the group of pediatric patients according to the referral patterns and results of 13C-urea breath test (13C -UBT) in our laboratory. The secondary aim is to investigate the result of different treatment combinations for Hp eradication. METHODS: The 13C-UBT was performed with 75 mg urea labeled with 13C in 200 mL orange juice. Breath samples were collected at 0 and 30 minutes, and the results expressed as the change in the 13C/12C ratio at T30' minus T0' The cutoff for Hp eradication was 3.5. The physicians who ordered the test completed a questionnaire covering demographic data (age, gender, and origin), indication for the test was use of a proton pump inhibitor (PPI), and type of combination eradication therapy. RESULTS: The study sample consisted of 1655 children, aged 1 to 18 years, 992 (59.9%) boys and 663 (40.1%) girls, from all parts of the country. The 13C-UBT was positive in 763 (46.1%). The prevalence of positive results was directly correlated with age. History of peptic disease was the main indication for the test, in 1346 (81.4%) cases. Details on eradication therapy were available for 435 children of whom 42.5% had a positive 13C-UBT, indicating a successful eradication rate of 57.5%. Compared with Israeli and American-European origin, children of Asian-African origin had a higher rate of referrals for reason of validation of successful Hp eradication, greater long-term PPI use, and a higher rate of 13C-UBT positivity. No significant difference was demonstrated between the triple therapy regimens used. CONCLUSION: 13C-UBT may be performed in children of all age groups. The main indication is a history of peptic ulcer disease. The prevalence of Hp infection increased with age and the only factor associated with increased Hp infection was Asian-African origin. The most frequent eradication therapy used in children is a combination of omeprazole, amoxicillin, and clarithromycin.

Adolescent↗
PubMed2003

Hyperplastic gastric polyposis, hypergastrinaemia and colorectal neoplasia: a description of four cases.

BACKGROUND AND AIMS: Previous reports have suggested a possible association between hyperplastic polyposis and colorectal neoplasms. Increased gastrin may be the link between these two conditions insofar as gastrin has been reported to be a growth-promoting tumoural agent. This report describes gastric polyposis, hypergastrinaemia and colorectal neoplasms in four elderly patients. METHODS: Four male patients with no family history of cancer, who were found to have multiple gastric hyperplastic polyps, hypergastrinaemia and colorectal cancers or an adenomatous polyp, were evaluated. Assessment included clinical evaluation, biochemical and haematological profiles, fasting gastrin levels, Helicobacter pylori serology, cobalamin, parietal cell antibodies, gastroscopy with biopsies of polyps and gastric mucosa, urease tests, and colonoscopy with biopsies of colorectal neoplasms. Immunohistochemistry of specimens from gastric polyps and colonic carcinomas was performed for chromogranin A, synaptophysin, Leu 7, neuron-specific enolase and gastrin. RESULTS: The mean age at diagnosis of gastric polyps was 71.2 years and at removal of colorectal neoplasm was 70.0 years. In two patients, the gastric lesion was diagnosed before the colonic lesion and conversely in the two remaining patients. Gastrin was very high (1604 pg/ml; normal level, < 115 pg/ml) in one patient with pernicious anaemia, and the mean level for the other three was 324 pg/ml. H. pylori were found in two patients. Immunohistochemistry failed to identify neuroendocrine cells in the hyperplastic gastric polyps and three of the colonic carcinomas. CONCLUSIONS: Occurrence of sporadic colorectal neoplastic lesion in patients with diffuse hyperplastic gastric polyposis and hypergastrinaemia may represent a new syndrome. Gastrin is not secreted by the gastric polyps or colonic carcinomas and may be related to gastric mucosal changes and H. pylori colonization. In patients with hyperplastic gastric polyposis and hypergastrinaemia, colorectal neoplasms should be ruled out.

Aged↗
PubMed2003

Surgical clip found in duodenal ulcer after laparoscopic cholecystectomy.

The wide use of surgical clips in laparoscopic surgery has led to a variety of complications. We describe two cases in which a surgical clip was incorporated into a duodenal ulcer after laparoscopic cholecystectomy. The presenting symptom was acute gastrointestinal bleeding. Both patients were treated endoscopically, and the bleeding stopped after the clip was removed from the ulcer base. Although the mechanism by which a surgical clip migrates into the duodenum is unclear, we recommend meticulous Calot's triangle dissection and removal of any wandering or misplaced clips. Endoscopic removal is recommended when a surgical clip is discovered in a bleeding ulcer.

Aged↗
PubMed2003

Effect of proton pump inhibitors on the continuous real time (13)C-urea breath test.

OBJECTIVE: The aim of this study was to evaluate the accuracy of a new, continuous real time (13)C-urea breath test, BreathID, for the diagnosis of Helicobacter pylori in patients taking proton pump inhibitors (PPIs). METHODS: Fifty-two consecutive patients, positive for H. pylori by BreathID, were prospectively evaluated. Patients were randomized to receive either omeprazole 20 mg/day or pantoprazole 40 mg/day for 14 days. A repeat breath test was performed on day 14 while patients received their last PPI pill. Patients were given a test drink containing 75 mg (13)C-urea and 4.0 g citric acid. Real time, continuously sampled expired (13)CO(2), obtained within 6-20 min, was compared with measurement of expired (13)CO(2) by isotope ratio mass spectrometry (IRMS). RESULTS: A full set of test data was available for 43 patients. After 14 days of treatment with PPIs, false negative detection of H. pylori occurred in only 1/43 (2.3%) patients examined by continuous real time (13)C-urea breath test compared with 2/43 (4.6%) patients examined by IRMS. With the exception of one case, complete agreement was observed between BreathID and the IRMS breath tests at both baseline and after PPI treatment. PPI treatment was associated with three different types of responses on UBT: 1) one third of the patients developed a significant decrease in the (13)CO(2)/(12)CO(2) excretion, 2) roughly one third developed a significant increase in the post-PPI breath test results, and 3) results did not change significantly in the remaining patients. Linear regression analysis of 43 H. pylori-positive subjects indicated a significant positive association between baseline and post-PPI Delta (13)CO(2)/(12)CO(2) excretion. CONCLUSIONS: The use of a single test drink containing 4.0 g citric acid in BreathID, resulted in a low number of false negative results associated with sustained PPI treatment. Although there were some differences between BreathID versus IRMS, the type of PPI and the sampling method used do not appear to play a critical role in the detection of H. pylori by BreathID. According to these results, BreathID is a reliable tool for testing H. pylori in patients taking PPIs.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2003

Case-control study of screening colonoscopy in relatives of patients with colorectal cancer.

OBJECTIVES: The efficacy of colonoscopic screening and polypectomy for the prevention of colorectal cancer (CRC) is well accepted but has never been documented in a prospective, controlled study. Screening by sigmoidoscopy has been found to reduce mortality from cancer of the rectum and distal colon. Case-control studies provide an alternative method for determining the efficacy of screening methods. METHODS: Between 1998 and 2000, a total of 40 subjects were found to have CRC (study group) and 160 had a normal colon (control group) among asymptomatic individuals participating in a screening colonoscopy program for a high-risk population of first-degree relatives of CRC patients. We compared these groups for screening by fecal occult blood testing, flexible sigmoidoscopy, barium enema, and colonoscopy in the 10-yr period before the index colonoscopy. RESULTS: Screening colonoscopy was performed in only 2.5% of the case subjects and 48.7% of controls (p < 0.0001), and all screening procedures in 12.5% and 73.7%, respectively (p < 0.0001). A statistically significant difference was also found for screening with fecal occult blood test, but not for flexible sigmoidoscopy or barium enema. Significant adenomatous polyps >1 cm in diameter were detected and removed in 19% of the control group within 10 yr of the index colonoscopy. Six (15%) of the patients in the study group died of CRC. CONCLUSIONS: Screening by colonoscopy can prevent progression to CRC from adenomatous polyps and may reduce the mortality associated with this devastating disease.

Case-Control Studies↗
PubMed2003

Modulation of mucin synthesis by gamma-interferon in human colon adenocarcinoma cells.

OBJECTIVES: Recombinant human interferon has been shown to enhance the expression of histocompatibility antigens and certain tumor-associated antigens in a variety of carcinoma cell lines. Since many tumor-associated antigens are mucins, we investigated the effect of recombinant human gamma-interferon on mucin production and secretion by colon cancer cell lines. METHODS: Control and gamma-interferon-treated cells were labeled with [(3)H]glucosamine in DMEM-H16 medium with 5% FCS for 24 h. Analysis was performed by gel filtration on Sepharose CL-4B columns, and the high-molecular-weight glycoprotein eluted at the void volume from the cytosol and medium was counted (expressed as dpm/4 x 10(6) cells). In another experiment the void volume was compared to concentration curves of standard mucins (expressed as mg/10(7) cells). RESULTS: gamma-Interferon increased mucin synthesis in HT-29 and LIM-6 cells, but not in LS174T and CACO2 cells. In HT-29 and LIM-6 cells, mucin synthesis was induced by gamma-interferon in a dose-dependent manner. The percentage of mucin secreted into the medium was also increased. CONCLUSION: The heterogeneity of response of human colon cancer cell lines to gamma-interferon by mucin production may limit the specific role of gamma-interferon as a modulator of mucin-type tumor-associated antigens.

Adenocarcinoma↗
PubMed2003

Dyspepsia symptoms and Helicobacter pylori infection, Nakuru, Kenya.

The prevalence of Helicobacter pylori infection was studied in 138 patients with dyspepsia in a hospital in Nakuru, Kenya, and in 138 asymptomatic sex- and age-matched controls from the same population. Anti-H. pylori immunoglobulin (Ig) G was more prevalent in dyspeptic than asymptomatic persons (71% vs. 51%), particularly those <30 years old (71% vs. 38%). H. pylori seropositivity was associated with dyspepsia after adjusting for age, sex, and residence (urban or rural). Among adults, the association between H. pylori infection and dyspepsia remained after adjusting for the above factors and for educational attainment, family size, and manual occupation. H. pylori infection in asymptomatic residents of Nakuru, Kenya, was more prevalent in older persons, with a rate of 68%, than in those 31-40 years of age. However, young persons with dyspepsia had an unexpectedly high prevalence of H. pylori infection. H. pylori test-and-treat strategy should be considered in Kenyan patients with dyspepsia, particularly in persons <30 years of age.

Adolescent↗
PubMed2003

13C-urea breath test to validate eradication of Helicobacter pylori in an Israeli population.

BACKGROUND: The 13C-urea breath test is the best non-invasive test to validate Helicobacter pylori eradication. Serology is unreliable for this purpose due to the slow and unpredictable decline in the antibody titer. OBJECTIVES: To characterize a specific group of patients who were treated for H. pylori and tested for successful eradication by 13C-UBT in our central laboratory, to correlate the eradication success rate with specific drug combinations, and to evaluate other factors that may influence eradication success. METHODS: 13C-UBT for H. pylori was performed in the central laboratory of Clalit Health Services. The breath test was performed by dedicated nurses in 25 regional laboratories and the samples were analyzed by a mass spectrometer (Analytical Precision 2003, UK). The physician who ordered the test completed a questionnaire computing demographic data (age, gender, origin), indication, use of non-steroidal anti-inflammatory drugs or proton pump inhibitor, and combination of eradication therapy. RESULTS: Of the 1,986 patients tested to validate successful H. pylori eradication, 539 (27%) had a positive test (treatment failure group) and 1,447 (73%) had a negative test (successful treatment group). Male gender, older age and European-American origin predicted better eradication rates. Dyspeptic symptoms and chronic PPI therapy predicted treatment failure. Combination therapy that included clarithromycin had a higher eradication rate than a combination containing metronidazole. The combination of omeprazole, amoxicillin and clarithromycin achieved an eradication rate of 81.3%, which was better than the combination of omeprazole, metronidazole and clarithromycin (77.2%) (not significant), or of omeprazole, amoxicillin and metronidazole (66.1%) (P < 0.01). CONCLUSION: Gender, age, origin, dyspepsia and PPI therapy may predict H. pylori eradication results. Our findings also support an increase in metronidazole resistance of H. pylori strains in Israel, as reported in other countries. We recommend combination therapy with omeprazole, amoxicillin and clarithromycin and avoidance of metronidazole as one of the first-line eradication drugs.

Adolescent↗
PubMed2003

[Virtual colonoscopy in real life--is it that good?].

BACKGROUND: Colon cancer is the main cause of mortality among the gastrointestinal cancers in Israel. Early detection of the average risk population is recommended from the age of 50 to 75 years. Private departments of radiology aggressively advertise virtual colonoscopy for the early detection of colon cancer, although it is not recognised as such in any country. METHODS: We collected all cases in which virtual colonoscopy was followed by endoscopic colonoscopy in the same patient from four medical centers in Israel. RESULTS: Total discrepancy between the results of the two examinations was found in 2/3 of the patients. In some cases colon cancer was missed. CONCLUSIONS: The results presented herein, raise many questions and "red lights" as to the use of virtual colonoscopy in its present form for screening purposes in Israel unless it is in the setting of clinical research.

Advertising↗
PubMed2002

Resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime.

The resistance of Helicobacter pylori isolated in Israel to metronidazole, clarithromycin, tetracycline, amoxicillin and cefixime was tested in 138 isolates, including 28 from treatment failures. No resistance to tetracycline was detected. Resistance to amoxicillin was found in one isolate (MIC = 1.5 mg/L) from an untreated patient, and resistance to cefixime in two isolates from each group (P = 0.18). Resistance to metronidazole and clarithromycin was much higher in the isolates from treated than from untreated patients: 60.7% and 38.2% for metronidazole (MIC >or= 8 mg/L) (P = 0.03); 46.4% and 8.2% for clarithromycin (MIC >or= 2 mg/L) (P < 0.001). Therapeutic outcome would benefit from susceptibility testing, especially after treatment failure.

Amoxicillin↗
PubMed2002

The alkaline tide phenomenon.

The parietal cell is capable of secreting high concentrations of hydrochloric acid into the lumen of the stomach. The apical membrane of this cell contains K+H+ ATPase, which is responsible for proton transport into the lumen. Potassium and chloride channels are also present. The basolateral membrane of the parietal cell possesses transporters that maintain intracellular homeostasis. Specifically, large amounts of bicarbonate that are generated by carbonic anhydrase must be removed from the cell to prevent alkalinization. Efflux of bicarbonate into the blood after acid secretion can be detected and is known as the alkaline tide. Determination of the alkaline tide has been used to measure acid secretion. In this review, we summarize the published data.

Acid-Base Equilibrium↗