NIV, YARON M.D.
Research interests
Key Words: Mucin, colorectal cancer screening, gastric acid secretion,
Helicobacter pylori, JC virus
Research Fields: cancer, molecular & cellular biology, gastroenterology
1. Mucin and the gastrointestinal tract
Mucins are high molecular weight glycoproteins secreted by the epithelial surface of
the gastrointestinal tract and other tissues of the body. Seventeen mucin genes were
cloned and sequenced till today. Our research looked at mucin role in gastric
protection against acid and pepsin, changes in mucin secretion in the stomach infected
with Helicobacter pylori, effect of mucin secretion on the tumorigenicity and
metastatic potential of colorectal cancer cell lines, and the possible role of mucin
secreted in the gallbladder and stone formation. The unstirred layer of mucin
protecting the stomach is composed of two sub-layers of MUC 5AC and MUC 6.
MUC 5AC is depleted by Helicobacter pylori infection. Cell line that synthesizes and
secretes high amount of mucin are also more tumorigenic in nude mice, and have high
potential of metastasis to the liver.
2. Gastric acid secretion and alkaline-tide
The gastric parietal cell secret acid into the lumen and bicarbonate through the
basolateral membrane into the blood. Thus, alkaline-tide is measurable after
submaximal stimulus for gastric acid secretion. H2 antagonist and PPI may abolish
alkaline-tide as well as acid secretion.
3. Colorectal cancer screening and prevention
Fecal occult blood test, flexible sigmoidoscopy and colonoscopy are all recommended
for screening the average-risk population for colorectal adenomas and cancer. Cohort
studies and case-control studies were published in different populations in Israel.
Refusers for colorectal cancer screening are at increased risk for developing cancer.
Polypectomy may prevent cancer and save lives.
Prevention of colorectal cancer metastasis in nude mice with immunotherapy of BAT
MAg.
Screening of CRC with I-FOBT (immunochemistry).
Genomic instability (CIN, CIMP, MSI) and CRC, FAP and HNPCC.
JC virus and CRC.
4. NSAIDs and COX-2 inhibitors (COXIBs) and gastropathy, COXIBs in
prevention of adenoma recurrence in sporadic adenoma patients, rectal cancer in
patients with FAP taking sulindac.
5. Helicobacter pylori eradication in adults, children and the older population.
Helicobacter pylori epidemiology in Israel in the asymptomatic, symptomatic and
health professional subjects.
NIV, YARON M.D.
Teaching
1. Advanced course on “Gastrointestinal tract chemistry in health and
diseases”: Introduction to basic receptor mediated gastrointestinal
secretions: stomach, duodenum, pancreas, small intestine and bile, and
pathological implications. Exocrine and endocrine secretion regulation,
(3rd year, medical course).
2. The histology of premalignant, inflammation-induced, gastrointestinal
lesions, (3rd year, medical course)
3. Clinical course in gastroenterology (4th year)
4. Clinical Gastroenterology (4th and 6th year)
5. Basic Science Research of Medical and Surgical Residents