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עמוד בית
Wed, 19.06.24

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December 2007
I. Zbidi, R. Hazazi, Y. Niv and S. Birkenfeld

Background: Colonoscopy is the gold standard procedure for screening for colorectal cancer and surveillance after polypectomy or colorectal cancer surgery, for diagnosis in symptomatic patients and patients with fecal occult blood, and for screening in the high risk population. The adherence of referring physicians to the accepted recommendations can prevent long waiting lists for colonoscopy and save lives, costs and resources.

Objectives: To evaluate the knowledge of primary care physicians and gastroenterologists in Israel about current guidelines for colonoscopy screening and surveillance.

Methods: A 10-item questionnaire on proper follow-up colonoscopy for surveillance after polypectomy and screening for colorectal cancer in various clinical and epidemiological situations was administered to 100 expert gastroenterologists and 100 primary care physicians at a professional meeting. Answers were evaluated for each group of physicians and compared using the chi-square test.

Results: The compliance rate was 45% for the gastroenterologists and 80% for the primary care physicians. The rate of correct answers to the specific items ranged from 18.7% to 93.75% for the gastroenterologists and from 6.2% to 58.5% for the primary care physicians (P < 0.001 for almost every item).

Conclusions: The knowledge of physicians regarding the screening and surveillance of colorectal cancer needs to be improved.

 

 

 

November 2007
E. Gal, Z. Levi, I. Shemesh, N. Chorev and Y. Niv

Background: Open access gastroscopy allows physicians to refer patients for endoscopic procedures without a prior consultation.

Objectives: To compare the safety and efficacy of OAG[1] with gastroscopy performed after a gastroenterological consultation.

Methods: Patients referred for gastroscopy directly (open access) or after consultation with a gastroenterologist, by physicians in the departments of internal medicine and surgery at a major tertiary center, were compared for indications, background disease, outcome and diagnostic yield. The data were collected prospectively over a 5 month period following the introduction of OAG at the center. Physicians in both departments participated in an education program on the indications and procedure of gastroscopy. For each patient referred for OAG the attending physician completed a specially designed questionnaire that had to be signed by a senior physician. Data were managed and analyzed with Excel and SPSS software.

Results: The study sample comprised 494 patients: of whom 236 were referred for OAG and 258 after prior consultation. On multivariate analysis, hospitalization in the department of internal medicine was the only independent factor for OAG. Severe background disease and aspirin treatment had no effect on physician use of OAG, although they served as a “red light” for the gastroenterology consultants. There was no difference in the diagnostic yield of the procedures (26.4% normal findings for OAG and 28.3% for consultations) or in mortality rates. The main indications for referral to gastroscopy in the surgery department were melena, hematemesis, and "coffee grounds," and anemia and vomiting in the internal medicine department.
Conclusions: OAG is feasible and beneficial in an academic medical center setting, with no bias in appropriateness of indications or decrease in the diagnostic yield compared to the traditional approach. More attention should be directed to safety issues by the referring physicians







[1] OAG = open access gastroscopy


August 2005
Y. Niv
 Colorectal cancers develop as a consequence of genomic instability. Microsatellite instability is involved in the genesis of about 15% of sporadic colorectal cancers and in most hereditary non-polyposis cancers. High frequency MSI[1] has been associated with a favorable prognosis, however it is not clear whether this is because MSI-H[2] tumors are inherently less aggressive or because they are more sensitive to chemotherapy. Chemotherapy with a combination of 5-fluorouracil and leukovorin or levamizole has been the standard of care for high risk stage II and stage III CRC[3]; it is also used in stage IV CRC. Several in vitro studies have shown that colon cancer cell lines displaying MSI-H are less responsive to fluorouracil than microsatellite-stable cell lines. Human studies, all of them retrospective, yielded conflicting results. The selection of patients with CRC for 5-FU[4] treatment has been based so far on the stage of tumor rather than the biology of the tumor. Although surgical staging is highly predictive of survival, there are indications that the form of genomic instability within a patient’s colorectal tumor has clinical implications, with and without 5-FU treatment. This review suggests that patients with MSI-H colorectal tumors may not benefit from 5-FU-based chemotherapy and can avoid its potential side effects (nausea, diarrhea, stomatitis, dermatitis, alopecia, and neurologic symptoms) that occur in half the treated patients. If confirmed by future prospective randomized controlled studies, these findings would indicate that microsatellite-instability testing should be conducted routinely and the results used to direct rational adjuvant chemotherapy in colon cancer.


 


[1] MSI = microsatellite instability

[2] MSI-H - high frequency MSI

[3] CRC = colorectal cancer

[4] 5-FU = 5-fluorouracil


March 2003
Click on the icon on the upper right hand side for the article by Yaron Niv, MD. IMAJ 2003: 5: March: 198-200
February 2003
E. Gal, G. Abuksis, G. Fraser, R. Koren, C. Shmueli, Y. Yahav and Y. Niv

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 antibodies titer.

Objectives: To characterize a specific group of patients who were treated for H. pylori and tested for successful eradication by 13C-UBT[1] in our central laboratory and 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[2] 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 described in other countries. We recommend combination therapy with omeprazole, amoxicillin and clarithromycin and avoidance of metronidazole as one of the first-line eradication drugs.






[1]13C-UBT[1]  = 13C-urea breath test



[2] PPI = proton pump inhibitor


September 2002
Yaron Niv, MD and Shlomo Birkenfield, MD

Background: Guidelines are important for keeping family physicians informed of the constant developments in many fields of medicine.

Objectives: To compare the knowledge of gastroenterologists and family physicians regarding the diagnosis and treatment of gastroesophageal reflux disease in order to determine the need for expert guidelines.

Methods: A 25 item questionnaire on the definition, diagnosis and treatment of GERD[1] was presented to 35 gastroenterologists and 35 family physicians. Each item was rated on a four point scale from 1 = highly recommended to 4 = not recommended. A voting system was used for each group on separate occasions. The proportions of correct answers according to the level of recommendation were compared between the groups.

Results: The groups' responses agreed on only 4 of the 25 items; differences between the remaining 21 were all statistically significant. For 14 items, 70% of the gastroenterologists chose the grade 1 recommendation, whereas more than 70% of the family physicians chose mostly grade 2.

Conclusions: The gap in knowledge on gastroesophageal reflux disease between gastroenterologists and family physicians is significant and may have a profound impact on diagnosis and treatment. Clear and accurate guidelines may improve patient evaluation in the community.






[1] GERD = gastroesophageal reflux disease


June 2002
Yosefa Bar-Dayan, MD, MHA, Simon Ben-Zikrie, MD2, Gerald Fraser, MD, FRCP, Ziv Ben-Ari, MD, Marius Braun, MD, Mordechai Kremer, MD and Yaron Niv, MD
April 2001
Arie Regev, MD, Rafit Drori, MD, Gerald M. Fraser, MD and Yaron Niv, MD

Background: Alkaline tide is the transient increase in blood and urine pH following stimulation of gastric acid secretion. It is attributed to HC03 release from parietal cells in parallel with H+ secretion. The enzyme carbonic anhydrase is thought to be responsible for HC03 production from CO2 and 0H in the parietal cell.

Objective: To examine the effect of pretreatment with the carbonic anhydrase inhibitor, acetazolamide, on the alkaline tide phenomenon.

Methods: Ten patients with dyspepsia and demonstrable alkaline tide were tested on three separate days. The pH and base excess were determined in arterialized venous blood before and 45 minutes after an intramuscular injection of pentagastrin. The pH of the urine was measured before and 120 mm after pentagastrin injection. Measurements were performed after pentagastrin alone on day 1 following pretreatment with acetazolamide 60 mm before pentagastrin on day 2, and after the administration of acetazolamide alone on day 3.

Results: Following the administration of pentagastrin alone, the blood base excess increased by 1.61 +0.2 mEq/L (mean + standard deviation) and the calculated alkaline tide at 45 mm was 33.99 ±4.49 mEq. On day 2 with prior adminis­tration of acetazolamide, base excess decreased by 0.21 + 0.39 mEq/L, and the calculated alkaline tide was -3.28±7.57 mEq, which was significantly lower than on day 1 (P=0 0001). On day 3, following acetazolamide alone, the base excess values decreased by 0.53~0.2 mEq/L and the alkaline tide was -10.05 +3.33 mEq there was no significant difference compared with day 2 (P= 0.44).

Conclusion: Pretreatment with acetazolamide abolished the alkaline tide induced by pentagastrin. This finding supports the view that carbonic anhydrase has a major role in the alkaline tide phenomenon.

December 1999
Ram Dickman, MD, Chana Turani, MD, Elimelech Okon, MD, Gerald M. Fraser MD, and Yaron Niv, MD.
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