Want to Learn More About Bullfrogs?

EFFECTS OF INTRAMUSCULAR ALFAXALONE AND DEXMEDETOMIDINE IN BULLFROGS (LITHOBATES CATESBEIANA)

Stephanie Thi1; veterinary student

Stefanie Golden1, Julie Balko1 ,  Kate Bailey1

1North Carolina State University- College of Veterinary Medicine

Amphibians are common in the field, zoos, museums, and research. It is necessary for them to undergo handling, restraint, and medical care that cause stress, impacting their welfare.  

There is little information available regarding anesthetic drugs for amphibians. Previous studies show alfaxalone to be a fast acting and effective drug for immobilization in frogs, though subjects did not reach a sufficient level of anesthesia for surgery1. Dexmedetomidine has been shown to prevent nociception in frogs, though they maintained consciousness2. We hypothesized that alfaxalone in combination with dexmedetomidine would produce a safe and efficacious method of immobilization in bullfrogs.

Three trials were conducted with 10 bullfrogs, with one week washout period in between. Frogs were administered either intramuscular (IM) 12 mg/kg alfaxalone alone, 1 mg/kg IM dexmedetomidine alone, or alfaxalone and dexmedetomidine in combination. Any trial containing dexmedetomidine included 0.1 mg/kg atipamezole reversal IM at 2 hours of observation, and hourly after if clinical signs persisted. Respiratory rate, heart rate, sedation score, and response to insertion of a needle into a hind leg muscle were evaluated every 15 minutes from induction to recovery.

One frog did not recover from anesthesia (9/10 frogs survived). Alfaxalone alone caused immobilization in bullfrogs, but inconsistent responses to needle insertion. Dexmedetomidine IM alone did not produce noticeable effects. Dexmedetomidine combined with alfaxalone caused immobilization of longer duration with reduced response to needle insertion when compared to alfaxalone alone. Therefore, the combination of these two drugs might provide effective anesthesia. 

Category: Anesthesiology/Clinical Medicine

Funding: Bailey Start Up Funds

References

1. LP Posner, KM Bailey, EY Richardson, AA Motsinger-Reif, CA Harms 2013. Alfaxalone Anesthesia in Bullfrogs (Lithobates Catesbeiana) By Injection or Immersion. J. of Zoo and Wildlife Medicine 44(4): 965-971. NCSU Libraries. 
2. GM Brenner, AJ Klopp, LL Deason, and CW Stevens 1994. Analgesic potency of alpha adrenergic agents after systemic administration in amphibians. Journal of Pharmacology and Experimental Therapeutics 270(2):540-545. NCSU Libraries.
   

Gular Reflex

Recording heart rate with Doppler

25 gauge needle used to assess response to noxious stimuli

Bullfrog regaining righting reflex

Research Highlight

Check out this abstract for some cool research Sophie Cressman from Ohio State University! She is in the middle of helping with using a mouse model to try and make pretreatment more effective for adoptive cell transfer therapies useful in human cancer treatment, HIV treatment, and CAR T-cell therapy. Pretty cool, huh?

Adoptive T-cell gene therapy, including Chimeric Antigen Receptor (CAR) T-cell therapy, is a new treatment method being investigated as a potential cure for certain cancers and other previously incurable diseases like HIV/AIDS. The efficacy of the therapy can be significantly improved by preconditioning patients before cell transplantation. During preconditioning, lymphodepletion treatment ablates lymphoid cells to create a favorable “space” for the transferred cells. Current lymphodepleting preconditioning methods, however, rely on high doses of toxic and non-specific chemotherapies which often result in variable therapeutic efficacy of CAR T-cells in patients and cause adverse and sometimes deadly side effects.

The general hypothesis is that CD3e-immunotoxin (CD3e-IT) treatment will work as a viable preconditioning method for T-cell gene therapy by depleting all organs’ T cells prior to adoptive T-cell transplant and promoting the survival then repopulation of transplanted T-cells. CD3e-IT, an anti-CD3e monoclonal antibody conjugated with diphtheria toxin, is a potentially safer and more effective preconditioning regimen for adoptive T-cell therapy. The Kim lab has recently developed a murine version of CD3e-IT using murine CD3e monoclonal antibody with Fc silencing mutations and, in a preliminary study, found that CD3e-IT can specifically and effectively ablate the majority of T-cells in all organs, except CXCR5+ follicular T-helper cells (Tfh). Tfh in germinal centers (GC) are especially important in HIV infection as they remain a reservoir for HIV such that viral infection can persist even after antiretroviral therapy. Tfh are also significant therapeutic targets for follicular lymphomas of GC origin including follicular lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and angioimmunoblastic T-cell lymphoma. The goal of this study is to enhance the safety and efficacy of adoptive T-cell gene therapy by finding lymphodepletion preconditioning treatment conditions that will safely and effectively ablate all T-cells in the body, including Tfh, to promote the survival and functionality of adoptively transferred T-cells.

Do male jumping spider display colors function as sensory traps to avoid cannibalism?

Lauren Gawel, Michelle Brock, Lisa Anne Taylor; Department of Entomology and Nematology, University of Florida

Abstract
Evolution of male ornamentation is often driven by sexual selection. Male color patterns may act as ‘sensory traps’ that exploit already-existing color biases in females that spill over from other contexts. In jumping spiders, many males display bright colors like those used by prey to warn of toxicity (e.g., red patches and black-and-white stripes). We hypothesized that since females are expected to avoid bright colors, males with black and white striped facial patterning would have a lower risk of being attacked by females; therefore, they would also have a lower risk of cannibalism by females. We tested this hypothesis using the jumping spiders Habronattus trimaculatus and Phidippus regius. Males display black-and-white stripes on their faces and front legs, respectively (directed at cryptically-colored females). If these stripes function as a sensory trap, we would expect females to avoid attacking black and white striped prey. To test this, we presented spiders with termites that had colored ‘capes’ adhered to their abdomens (black, white, or black-and-white striped). Results showed that the spiders attacked striped termites (and black termites) at significantly lower levels than the white termites. This is consistent with our hypothesis that black-and-white patterns in male displays might effectively reduce cannibalism risk. While studies of sensory traps have been done in other animals, our study takes a novel approach examining the balance between attracting a female and avoiding risks associated with courtship.

Honorable Mention, Life as a Vet Student
Amanda Fischer, Cornell

My first year of veterinary school I never would have guessed that I would be writing an article for the Vet Gazette, let alone from a lab bench (when I should be in clinics).  The tale of my love affair with bench work started when I was an undergraduate at Cornell. In my manic attempts to diversify my resume for veterinary school, I applied for an undergraduate research assistant position.  I interviewed with John Parker, BVMS, PhD for the chance to work at the Baker Institute for Animal Health.  He told me there were other applicants, so when I was hired I felt like I’d won something.  It was the first job I’d applied for on my own.  Once I started, most of my time was spent predictably re-stocking laboratory supplies, but my project is what kept me interested in research.

If anyone reading has done immunofluorescent staining you know how infuriating and rewarding the process can be.  The first time I looked at feline cells that I had successfully stained for feline calicivirus protein, I was enthralled.  I could have stared at those cells forever. I was looking at virus infected cells and was looking at the virus! In the cells! I was seriously impressed with myself.  I tried to continue working in the lab, but there wasn’t funding for me to stay because he had a veterinary student working during that summer.

Fast forward to veterinary school, where I assume it’s common knowledge that the best way to make money over the summer is to conduct research.  With our level of debt, it’s hard to say no to stable income and housing you’ve already paid for.  I participated in Cornell’s Veterinary Investigator Program (VIP) my first summer.  I actually got paired up with Dr. Parker, which was great because I could pretend like I already had an idea about what I was doing.  I greatly enjoyed my incredibly frustrating project where I made no significant findings after 2 months.  The fact that this didn’t deter me from continuing to go to lab and find projects to work on speaks volumes about my personality.  I hope that my persistence will come in handy as a doctor.  But for now it’s serving me well in terms of keeping me gainfully employed as a student.  I also spent my second summer in the Parker lab, as a second year VIP participant.  It was around that time that I learned about an interesting opportunity to take a year off from veterinary school to do research full time...

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Gene Therapy for Osteoarthritis: Kinematic Analysis

Entry, Cases/Abstracts
Nichole Hughes, University of Florida

Steve Ghivizzani, MD; Patrick T. Colahan, DVM; Nichole Hughes
Department of Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville FL
Department of Orthopedics and Rehabilitation, University of Florida College of Medicine,  Gainesville FL
Research supported by Merial

Osteoarthritis (OA) is one of the most prevalent diseases worldwide, causing chronic joint pain and progressive immobility due to the erosion of articular cartilage, subchondral bone sclerosis, and osteophyte formation. Though OA is widely unaffected by current treatments, experimentation has shown that local gene delivery of IL-1Ra (receptor antagonist) using scAAV (self-complimentary adeno-associated virus) vectors can have a significant effect in disease progression in animal models and allow sustained levels of IL-1Ra in the joint. This project uses kinematic analysis to evaluate the capacity of scAAV-mediated delivery of equine-IL-1Ra to block the development of experimental arthritis in the equine joint. To evaluate the therapeutic efficacy of scAAV-eqIL-1Ra, an osteochondral fragment (OCF) model is used to simulate the pathobiology of OA. After a recovery period, scAAV-eqIL-1Ra and placebo (saline) are delivered to the experimental and control groups, respectively. Motion analysis is conducted weekly on a high speed treadmill for 12 weeks. Quantifiable changes in kinematics are measured using Lameness Locator® software.

It is expected that local, intra-articular treatment with scAAV-eqIL-1Ra will provide protection from the development of the articular pathologies associated with OA.  Relative to placebo controls, treated animals should have reduced pain and improved mobility, thus resulting in a reduction in lameness as analyzed by the Lameness Locator. Thus far, only 5/20 horses have completed the project.  The kinematic analysis of these 5 horses shows that the placebo improves lameness at a rate 2.5 times faster than treatment with scAAV-eqIL-1Ra. However, it is too early to use these preliminary results to determine the overall efficacy of the therapy. Ultimately the final data from this part of the study will be compiled with MRI, radiography, arthroscopy, and data generated from recovered fluids and tissue biopsies to provide a comprehensive description of the effects of the gene based treatment. Based on these efficacy models in horses, we can gain insight on the use of gene transfer on a human scale as a therapy for osteoarthritis.