Internal Medicine

Below, please find links to all of the clinical trials involving internal medicine. The studies include a multitude of information, including (but not limited to) the study’s purpose, benefits for participating, and financial incentive information. If you have any questions, please contact the individual outlined at the end of each trial summary.

Please visit the Internal Medicine service webpage at the Veterinary Medical Teaching Hospital (VMTH) if you would like to learn more about the amazing things that our veterinarians can do for you and your animal.


Ureteral obstructions: Evaluating Post-Surgery Outcomes

Title: Evaluation of Post-operative Outcome in Cats Undergoing Ureteral Stent Placement to Relieve Ureteral Obstruction

Purpose of Study: The purpose of this project is to record the intra-operative and postoperative complications associated with the procedure and determine the outcome of the procedure based on objective measures.

Participation Requirements: Cats with benign ureteral obstruction

Initial Evaluation for Participation: Contact Dr. Culp for details at or (530) 752-1393

Procedures: Cats with a diagnosis of benign ureteral obstruction will be enrolled in the study. Bloodwork values that can be utilized to determine the function of the kidney (should improve with the passage of urine) as well as variables such as the size of the kidney collecting system and ureter (should decrease with passage of urine) in cats both pre- and postoperatively will be evaluated. Lastly, the change in the urine output of cats with ureteral stents will be assessed to determine if the stents improve output.

Benefits: The benefits of enrolling a patient in this study are financial. Some of the pre- and post-stent placement bloodwork and pre- and post-stent placement ultrasound evaluations will be paid for by the study.

If this therapy proves to be beneficial, it will have important clinical applications for other cats with the same condition.

Owner Responsibilities: The owner is responsible for returning with their cat 2 weeks and 3 months after stent placement.

Contact: Contact Dr. Culp for details at or (530) 752-1393.


Inflammatory Bowel Disease: Evaluating a Stem Cell Therapy

Title: Immunomodulation by Mesenchymal Stem Cells In Canine Inflammatory Bowel Disease

Purpose of Study: Inflammatory bowel disease (IBD) in dogs often involves lifelong steroid therapy, which holds the risk for a variety of potentially serious complications. Because of the ability to regulate immune responses and facilitate tissue regrowth or repair, we believe that fat-derived, mesenchymal stem cells (MSCs) may help to decrease the abnormal immune response and the accompanying inflammation. Therefore, the purpose of this study is to investigate the effectiveness of a new stem cell therapy for canine IBD and better understand how stem cells work to limit inflammation and repair gut tissue.

Participation Requirements: Dogs suspected of having inflammatory bowel disease (IBD), specifically adult dogs with chronic, idiopathic, diarrhea (>3 weeks) that have failed dietary management (4-6 weeks) and empiric antimicrobial therapy (minimum 2 week course of metronidazole and/or Tylosin therapy) for their disease.

Initial Evaluation for Participation: Prior to enrollment, dogs will have received the full diagnostic work-up that includes a fecal screen for endoparasites, a CBC, serum biochemistry profile, urinalysis, measurement of serum B12 and folate concentrations, and abdominal ultrasound. Additional screening tests will be performed at the discretion of the attending gastroenterologist.

  • Exclusion criteria - Dogs previously (< 2 months) or currently treated with corticosteroids and/or non-steroidal anti-inflammatory drugs (NSAIDS) will be excluded from the study.

Procedures: If you agree to let your dog participate in this study, the following will happen:

  • Visit 1: On the day of study enrollment, your dog will have belly fat and full thickness gut biopsies collected via a minimally invasive surgery performed under general anesthesia. Prior to anesthesia, we will collect approximately 20ml of blood. During the procedure, we will collect a golf ball-sized amount (10-20 grams) of abdominal fat and the draining lymph node.
  • Visit 2: Two to three weeks after fat harvest, your dog will either receive the placebo or a dose of 25 million MSCs given by intravenous infusion. Dogs receiving the placebo will also receive the medical standard-of-care (steroid therapy) at the same time points as treatment group dogs.
  • Visit 3: Two weeks after the first treatment, your dog will receive a second injection of either stem cell treatment or placebo according to their group assignment. At this time, we will clinically examine your dog and collect about 20ml of blood.
  • Visit 4: Two weeks after the second treatment, we will clinically examine your dog and collect about 20ml of blood. Afterwards, your dog will be anesthetized and undergo a minimally invasive endoscopic examination of its gut with a flexible endoscope. Partial thickness gut biopsies and ultrasound guided abdominal lymph node aspirates will be collected at this time.
  • Follow-up: You will then be asked to return for clinical follow-up and blood sampling 2 more times within a 4-week interval.

Benefits: We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include the potential of your dog to achieve a state of remission from IBD without the use of steroid therapy. Moreover, this study may help us to further target specific use of stem cells for other dogs or even humans that suffer from inflammatory bowel disease.

Owner Responsibilities: You are only responsible for covering the cost of an endoscopic examination had your dog not been enrolled in the study (i.e., the standard-of-diagnosis that your dog would have received at the time of the first visit). The study will cover everything else, including the examination fees, cost of biopsy processing and interpretation, the difference between the costs of the laparoscopic and endoscopic (standard-of-diagnosis) procedures performed at the first visit, and procedures involved with fat harvest and stem cell expansion, the second endoscopic procedure, and ultrasound guided abdominal lymph node aspirate.

Contact: Dr. Amir Kol (

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Ectopic ureters: Evaluating Laser Ablation as a Treatment Option

Title: Evaluation of the Use of Cystoscopic-Guided Laser Ablation in the Treatment of Canine Ureteral Ectopia

Purpose of Study: To evaluate urethral pressure profiles (UPPs) in patients undergoing laser ablation of their ectopic ureters. The goal is to determine if pre-treatment UPP values can help to predict continence rates after laser ablation.

Participation Requirements: Any dog with ectopic ureters that will be undergoing laser ablation may be included in the study. Owners must give approval for pre-treatment UPP measurements to be performed.

Initial Evaluation for Participation: Patients must undergo evaluation and diagnostic workup for ectopic ureters and there must be a high clinical suspicion that the patient has an ectopic ureter.

Procedures: The procedures that will be performed as part of this study are currently utilized in the diagnostic workup and treatment of ureteral ectopia, and include:

  • Urethral pressure profilometry (UPP) - Performed in a manner similar to what has been described previously and involves the placement of a urinary catheter into the urethra via a transvulvar approach (non-invasive).
  • Cystoscopic-guided laser ablation procedure - Performed via a transvulvar approach and involves the use of a laser to ablate the intramural portion of ectopic ureteral tissue.

Benefits: The benefits of enrolling in this study include financial support for pre-procedure diagnostics as well as support towards the performance of the cystoscopic-guided laser ablation procedure. Additionally, funding from this grant will be applied towards the anesthetic event.

Owner Responsibilities: Owners will need to give their approval for urethral pressure profilometry evaluation.

Contact: Dr. Carrie Palm (

Hiatal Hernia / Brachycephalic Obstructor Syndrome: Assessing a Surgical Treatment

Title: Effect of Surgical Treatment of Brachycephalic Obstructor Syndrome on the Lower Esophageal Area of Brachycephalic Dogs with Evidence of Hiatal Herniation and Gastroesophageal Reflux

Purpose of Study: We believe that brachycephalic dogs have a tendency to develop hiatal herniation (HH) with greater frequency than non-brachycephalic dogs. Dogs with relative obstruction of the upper airways may generate a decreased pressure in their chest during inspiration (breathing in) that results in the upper part of the stomach being sucked into the chest (HH). This can lead to clinical signs including regurgitation, esophageal stricture formation and aspiration pneumonia if severe. We hypothesize that, if the upper airway obstruction in these dogs can be alleviated, improvement in their respiratory compromise might be seen as well as a reduction in the severity of their HH.

Participation Requirements:

  • Brachycephalic breed (dogs with broad short skulls)
  • No evidence of other upper airway obstructive pathology (especially tracheal collapse and hypoplastic trachea)
  • No previous brachycephalic surgery
  • Evidence of hiatal herniation on fluoroscopic imaging (performed pre-operatively)

Initial Evaluation for Participation: Initial evaluation and discussion for entry into the study can be arranged by making an appointment with our Internal Medicine or Soft Tissue Surgery or by contacting Dr. Phil Mayhew directly (contact information below).

Procedures: Both visits outlined below require hospitalization for 2-4 days at the VMTH.

  • First visit:
    • Day 1: You will be asked to fill out a questionnaire about your dog’s clinical signs. We will give your dog a local anesthetic, place a small catheter down your dogs nose, and give your dog a small amount of water to swallow, so we can trace the pressure profile of your dog’s esophagus (known as high-resolution manometry or HRM study). We will then perform a barium esophagram, which involves imaging of your dog using a fluoroscope (moving x-ray machine) after he/she swallows water and food boluses. Finally, we will place a small pH-monitoring probe in you dog’s nose that will remain in place for no longer than 24-hours for continuous monitoring of the esophageal pH and will be removed prior to surgery the following day.
    • Day 2: Your dog will be prepared for surgery and given general anesthesia. Prior to surgery, we will take measurements of your dog’s lower esophageal area (impedance planimetry or Endoflip), which involves inflation of a very low-pressure balloon within the lower esophagus, and perform an upper gastrointestinal endoscopic study immediately before upper airway surgery.
  • 30 – 60 days post-surgery visit: You will need to bring your dog in for another visit between 30 and 60 days after surgery. During this visit, we need to repeat the questionnaire and the procedures outlined above to gauge the response to surgery.

Benefits: The trial will pay for all of the diagnostic tests associated with the study, including costs associated with the HRM and esophagram studies, Endoflip measurements, pH impedance studies, endosocopic studies, biopsy procedures, pathology fees as well as the hospitalization and anesthesia fees associated with the second visit to the hospital at 30-60 days post-operatively. The owner will have to cover the surgical procedure, hospitalization and any possible complications associated with the surgical procedure and recovery during the first visit.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include a better understanding of your dogs presence or absence of hiatal herniation which may aid in longer-term management of this component of his or her clinical signs. Results from this study may influence treatment of other dogs with similar conditions going forward.

Owner Responsibilities: If you allow your dog to participate in this study, you will be responsible for bringing the dog to the VMTH for the study-related visits for the duration of the time stipulated and for providing the clinical information stipulated.


  • Please call (530) 752-1393 to make an appointment with Soft Tissue Surgery or Internal Medicine for Dr. Phil Mayhew's study
  • Email Dr. Phil Mayhew directly at
Intrahepatic Portosystemic Shunts: Assessing a New Treatment Technique

Title: Assessment of Outcome in Dogs Undergoing Percutaneous Transvenous Coil Embolization to Treat Intrahepatic Portosystemic Shunts

Purpose of Study: The purposes of this project are to:

  1. Evaluate serum bile acid concentrations and hepatic biochemical functional parameters (BUN, albumin, cholesterol, glucose, and bilirubin) in dogs with intrahepatic portosystemic shunts both pre- and post-treatment to objectively evaluate each patient for improvement in hepatic function.
  2. Assess the improvement in the clinical signs of dogs with IHPSS after the performance of PTCE.
  3. To perform imaging studies pre- and post-PTCE that provide objective assessment of outcome associated with the PTCE procedure.

Participation Requirements: Dogs with intrahepatic portosystemic shunts

Initial Evaluation for Participation: Contact Dr. Culp for details at or (530) 752-1393.

Procedures: Dogs with a diagnosis of intrahepatic portosystemic shunts (IHPSS) will be enrolled in the study. The dog will undergo percutanous transvenous coil embolization (PTCE) to treat his/her IHPSS. Prior to and after this procedure, diagnostics including bloodwork, nuclear scintigraphy, abdominal ultrasound and computed tomography (CT) scan will be performed and compared.

Benefits: Enrolling a dog in this study results in a significant financial incentive towards diagnostics that would be recommended for the dog whether or not he/she is enrolled in the study. This benefit includes payment of the preoperative CT scan and the postoperative bloodwork (1 chemistry panel at 3 months postoperative), ultrasound (1 at 3 months postoperative), nuclear scintigraphy scan (1 at 3 months postoperative) and CT scan (1 at 3 months postoperative).

Owner Responsibilities: Return the patient 3 months after treatment for further assessment.

Contact: Contact Dr. Culp for details at or (530) 752-1393.

Large Bowel Disease: Evaluating a New Diagnostic Tool

Title: Evaluation of CT as a diagnostic tool for large bowel disease in dogs

Purpose of Study: We are evaluating the benefits of a novel CT protocol for large bowel disease. Surgical planning for conditions of the large bowel can be difficult as there are many ways to surgically approach lesions of the large bowel. Appropriate surgical planning plays a large role in the success of the procedure. While existing imaging methods provide some information about the lesion, there are sometimes major limitations to the information provided. Three-dimensional imaging, such as CT, is likely to improve our understanding of the disease and, our surgical planning in cases of mass lesions.

Participation Requirements:

  • Dogs experiencing clinical signs of large bowel disease (colon or rectum)
  • As the owner, you have elected to have a colonoscopy and biopsies performed under general anesthesia for diagnosis of the underlying disease

Initial Evaluation for Participation: Evaluation by the UCDavis VMTH Internal Medicine Service

Procedures: If you agree to participate, your dog will be anesthetized according to standard of care recommended by the Anesthesia Service. Prior to your dog’s scheduled colonoscopy, your dog will go to CT for the imaging scan using a new technique. He/she will then proceed for his/her colonoscopy/biopsy procedure as planned.

Benefits: There is no charge for you to allow your dog to participate in this clinical trial as all costs associated with the study, including the CT scan and additional anesthesia time needed to perform the CT imaging will be paid by the sponsor/department. You will additionally receive an additional $150 subsidy on your bill toward the cost of the colonoscopy procedure.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include improved methods of diagnosis of large bowel disease or improved surgical planning for focal large bowel problems.

Owner Responsibilities: If you allow your dog to participate in this study, you will be responsible for bringing your dog to the U.C. Davis Veterinary Medical Teaching Hospital (VMTH) for his/her scheduled colonoscopy procedure and for covering the standard costs of the colonoscopy/biopsy/regular medical care as part of the diagnosis of your dog’s disease.

Contact: If you are interested in participating in this clinical trial, please schedule an appointment with the UCD VMTH Internal Medicine Service at 530-752-1393. For specific procedure questions, have your veterinarian contact Dr. Michele Steffey at 530-752-1393 and following the prompts for Surgery.

Printable Flyer (PDF)