John Geibel, DSc, MD, AGAF, MS, FRS

Professor of Surgery (Gastrointestinal) and of Cellular And Molecular Physiology; Vice Chair, Surgery; Director, Surgical Research; American Gastroenterological Association Fellow; Fellow of the Royal Society of Medicine

Research Departments & Organizations

Cellular & Molecular Physiology

Surgery

Yale Cancer Center: Signal Transduction

Office of Cooperative Research

Research Interests

Chemicals and Drugs; Diarrhea; Electrophysiology; Gastric Acid; Gastroenterology; Physiology

Research Summary

Our primary focus is on real time monitoring of ion transport mechanisms in epithelia, using high-resolution microscopy. One of the crucial problems facing all epithelial cells is the control of the intracellular milieu. In an effort to maintain ionic homeostasis, epithelial cells have devised a variety of ion channels, transport proteins, and carriers to regulate and maintain the intracellular ionic concentrations. To further understand how ions are transported in epithelial cells, we have developed a variety of optical techniques to continuously monitor intracellular ionic concentrations in real time. Using high-resolution video or confocal microscopy we are presently able to monitor intracellular Ca2+, Na+, K+, Cl-, pH, and membrane potential. We are currently investigating various aspects of renal tubule and gastric tissue ion transport in intact renal tubules and gastric glands. We also are characterizing the secretory and reabsorptive properties of the colonic crypt, with a special focus on diarrheal disease.

Specialized Terms: Gastric Acid Secretion; Colonic Fluid Transport; Renal Physiology; Intracellular Ion Activity Measurements; Calcium Sensing Receptor; Diarrheal disease; electrophysiology; CFTR; AMPKinase volume regulation

Extensive Research Description

We are focused on 3 main areas; gastric ion transport in health and disease, intestinal ion transport in health and disease, and 3DBioprinting. For gastric ion transport we are focusing on means to modulate acid secretion and reverse erosion. We use a combination of natural products and biochemical modifications to treat acid disease at the cellular level. For studies of intestinal ion transport, we are focusing on how the calcium sensing receptor(CaSR) can modulate fluid transport during toxin induced diarrhea. We are also looking at nanoparticle therapies for Ulcerative Colitis. In addition we are investigating means to prevent ischemic injury by activating ionic pathways using the AMPKinase. Finally we are trying to prevent IBD/IBS associated epithelial injury in the gut by CaSR activation using nutraceuticals  . For the 3DBioprinting area we are developing replacement conduits that can be used for the aorta, the inferior vena cava, and also as small and large intestine repair tool. Along with this research we are now examining the potential for intestinal elongation using a 3D printed replacement.

Activities

  • The gut and acid-base transport/homeostasis Florence, Italy (2009 - 2009)

    ISN Forefronts Symposium on Renal and Extrarenal Control of Acid-base Homeostasis in Health and Disease

  • Invited Plenary Speaker, World Nephrology Congress Cape Town, South Africa (2009 - 2009)

    Lecture on the Role of the Calcium Sensing Receptor in Kidney and Intestinal Tissues

  • Role of Electrolyte Transport in the Gut Milan, Italy (2009 - 2009)

    Invited Speaker International Society of Nephrology

  • The Intestine as a substitute for renal electrolyte transport Naples, Italy (2009 - 2009)

    Invited Speaker Borelli Conference on Renal Physiology

  • Invited Speaker, First Paracelsus Medical University Graduation Salzburg, Austria (2008)

    Invited Speaker, First Paracelsus Medical University Graduation

  • Invited Speaker, World Congress on Cell Volume Regulation Salzburg, Austria (2007)

    Invited Speaker, World Congress on Cell Volume Regulation

  • Invited Plenary Speaker, World Nanotechnology Congress Innsbruck, Austria (2006)

    Invited Plenary Speaker, World Nanotechnology Congress

  • Invited Guest Speaker, World Congress of Nephrology Berlin, Germany (2003)

    Invited Guest Speaker, World Congress of Nephrology

  • Invited Guest Speaker, International Nephrology Society, “ABC Cassette Binding Proteins” Switzerland (2003)

    Invited Guest Speaker, International Nephrology Society, “ABC Cassette Binding Proteins”

  • Invited Guest Speaker, International Biophysics Society Satellite Meeting Rio de Janerio, Brazil (2003)

    Invited Guest Speaker, International Biophysics Society Satellite Meeting

  • Invited Guest Speaker, Department of Physiology Zurich, Switzerland (2001)

    Invited Guest Speaker, Department of Physiology

  • Organizing Committee Forefronts in Nephrology Program, International Society of Nephrology Zurich, Switzerland (2001)

    Organizing Committee Forefronts in Nephrology Program, International Society of Nephrology

  • Invited Guest Speaker, University of Innsbruck Innsbruck, Austria (2000)

    Invited Guest Speaker, University of Innsbruck

  • Invited Guest Speaker, International Congress of Nephrology Argentina (1999)

    Invited Guest Speaker, International Congress of Nephrology

  • Invited Guest Professor, University of Tubingen, Department of Physiology Tubingen, Germany (1998)

    Invited Guest Professor, University of Tubingen, Department of Physiology

  • Invited Guest Speaker Brazilian Government Sao Paulo, Brazil (1997)

    Invited Guest Speaker Brazilian Government

  • Organizer of International Renal Electrolyte Symposia Vienna, Austria (1997)

    Organizer of International Renal Electrolyte Symposia

  • Invited Guest Professor Rio de Janeiro, Brazil (1996)

    Brazilian Government

  • Invited Guest Professor, Italian Government Naples, Italy (1995)

    Invited Guest Professor, Italian Government

  • Invited Speaker, 2nd Boreli Congress of Nephrology Capri, Italy (1995)

    Invited Speaker, 2nd Boreli Congress of Nephrology

Selected Publications

See list of PubMed publications

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Contact Info

John Geibel, DSc, MD, AGAF, MS, FRS
Lab Location
Brady Memorial Laboratory
310 Cedar Street, Ste 269/2

New Haven, CT 06510
Mailing Address
Gastrointestinal SurgeryPO Box 208062
New Haven, CT 06520-8062
Isolated Human Gastric Gland

Isolated gastric gland loaded with the pH sensitive dye BCECF and a lysosomal tracker on a Zeiss Spinning Disk confocal. Image shows 3-D reconstruction of the gland in real time.