Effects of injectable analgesics on selected gastrointestinal physiological parameters in rabbits

Debosree Pathak, a student at Oklahoma State Unversity, submitted her abstract about analgesics in rabbits! She is working on the full manuscript now, but check out a sneak-peak of what she found!

~Don't forget to submit your abstracts or cool case studies for a chance to win $100 for Issue 3~

Pathak D, Di Girolamo N, Maranville R, Womble W, Sypniewski L, Hanzlicek A, Brandão J

From the Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, 2065 W. Farm Rd., Stillwater OK 74074, USA.

Abstract

In rabbit medicine, it has long been postulated that analgesics, particularly opioids, decrease gastrointestinal motility. However, comparative studies investigating the gastrointestinal side-effects of different analgesics are lacking. This study sought to evaluate the effects of injectable analgesics (buprenorphine, hydromorphone, methadone, and meloxicam) on selected gastrointestinal physiological parameters in New Zealand white rabbits when compared to an injectable placebo (saline) and baseline data. In this randomized, blinded, complete cross-over controlled trial, ten healthy New Zealand white rabbits randomly received subcutaneous buprenorphine (0.1 mg/kg), hydromorphone (0.2 mg/kg), methadone (0.2 mg/kg), meloxicam (1 mg/kg), or a placebo (saline [equal volume to buprenorphine]) over a period of 10 weeks. Every 24 hours from day -1 to day 3, the rabbits were physically examined. The food and water intake, and fecal and urine output were recorded each day. Baseline data was obtained on day -1, and treatment was given on day 0. Day 1 to 3 were used to observe the treatment effects. A minimum 72-hour washout period between treatments was allowed. Generalized linear mixed models were employed and statistical significance was set at P<0.05. Buprenorphine decreased food consumption up to 72h and hydromorphone up to 24h. Fecal production (weight and/or pellet number) was decreased with buprenorphine up to 72h, and with methadone and hydromorphone up to 48h. Buprenorphine and hydromorphone decreased water intake up to 72h. Urine production was decreased with buprenorphine up to 48h and methadone up to 24h. Knowing the comparative effects among different analgesics will improve the medical management of rabbits.

Trend Analysis with Multiple Management Variables on Gastrointestinal Health in Zoo-managed Moose (Alces alces)

Abstract submitted by Alexandria Armeni from the University of Minnesota

Alexandria A. Armeni1*, Rachel Thompson DVM, Dipl ECZM (ZHM)1,2, Diana Weinhardt3, Trista Fischer3, Snigdhansu B. Chatterjee PhD4

1The University of Minnesota College of Veterinary Medicine, Saint Paul, MN 55108 USA; 2 Species360, Bloomington, MN 55425 USA; 3Minnesota Zoo, Apple Valley, MN 55124 USA;4The University of Minnesota College of Liberal Arts, Minneapolis, MN 55455 USA

Abstract

Moose are recognized to be difficult to maintain under human care in zoos, mainly due to their particular digestive physiology and resulting feeding demands1. A syndrome classified as “complex wasting syndrome” has been described in literature as a gradual process in which damage to the intestinal tract accumulates until the body can no longer compensate for that damage. Common manifestations of this syndrome are poor fecal consistencies and chronic weight loss2. This study aimed to investigate the “complex wasting syndrome” by retrospectively evaluating trends in fecal scores as they compare to grain, browse and supplements fed, as well as temperature and housing parameters. To maintain consistency, data was entered into a template created in the Species360 Zoological Information Management System Care and Welfare module.  Following common themes in literature, we hypothesized that grain, browse, and temperature would have a significant impact on fecal consistency scores, which are an indicator of gastrointestinal health in captive moose. Preliminary trends from the data suggest that the most significant factors were alfalfa, woodchips and seasonal behavior trends. Grain and temperature appear to have no significant effect on fecal score. Due to nutritional challenges observed in moose under human care, projects like this are of key importance for moose welfare. The successful display of healthy moose depends on improving their husbandry in zoos. This project has the potential to target areas critical for improving moose management.

ACKNOWLEDGMENTS

The authors would like to thank Minnesota Zoo, Species 360 and The University of Minnesota for their assistance in the collection and organization of the data for this project.

LITERATURE CITED 

1. Shochat, E., Robbins, C. T., Parish, S. M., Young, P. B., Stephenson, T. R., & Tamayo, A. (1997). Nutritional investigations and management of captive moose. Zoo Biology, 16(6), 479–494. 

2. Clauss, M., Kienzle, E., & Wiesner, H. (2002). Importance of the wasting syndrome complex in captive moose (Alces alces). Zoo Biology, 21(5), 499–506.

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

Shunt Case Report

Kristin Reichert, University of Wisconsin 

1. Signalment: Xxxx (not revealing name for patient confidentiality), 4-month-old intact female Golden Retriever

2. Presenting complaint: Intrahepatic Portosystemic Shunt 

3. History: Back in July, Xxxx reportedly presented to the emergency service with unspecified neurological signs. She underwent investigations that revealed elevated total bilirubin and ammonia, and she was transferred to the internal medicine service with a suspicion for a congenital hepatic portosystemic shunt. Upon abdominal ultrasound, internal medicine suspected that Xxxx had an intrahepatic shunt and recommended a soft tissue surgical consult. This would likely be for computed tomography with contrast to confirm the location of the shunt, followed by surgical management. To help mitigate her neurological signs from the accumulation of ammonia within her system and ultimate crossing of the blood brain barrier, Xxxx was prescribed levetiracetam, lactulose, and metronidazole. She was reported to have improved significantly with regards to her clinical signs as a consequence of these medications.

4. Physical examination findings: Xxxx presented BAR. Eyes and ears were noted to be unremarkable. Oral examination identified multiple fractured deciduous teeth. Mucous membranes were moist and pink with a capillary refill time of under 2 seconds. Heart rate and rhythm were normal with no murmur auscultated. Lung fields in all four quadrant were normal. Abdominal palpation was soft and comfortable. Peripheral lymph nodes palpated within normal limits. Integument had no abnormalities. Temperature remained within normal limits throughout hospitalization. Her presenting weight was 11.3kg.

5. Differential diagnoses: Upon presenting to the soft tissue service, the top differential was intrahepatic portosystemic shunt, due to the previous diagnostics that had been performed. However, upon initial presentation, differential list included ingestion of toxins, an episode of hypoglycemia causing seizures (potentially secondary to other disease processes), intracranial congenital defects causing seizures, idiopathic seizure activity, peripheral vestibular disease (including secondary to otitis media or otitis interna), neoplasia of the central or peripheral nervous system, infectious disease processes (including bacterial, viral, fungal) and a vascular event in the central nervous system.

6. Diagnostic tests/procedures and associated results: Whilst with the soft tissue service; a pre-operative complete blood count and serum biochemistry were performed in conjunction with an abdominal computed tomography scan with contrast, to confirm the location of the shunt and to appropriately prepare for our intraoperative approach.

7. Working diagnosis: Total bilirubin had returned to the normal range, which was slightly anomalous, however her ammonia had increased since her previous bloodwork, which remained consistent with the shunt persisting. The CT scan confirmed the presence of an intrahepatic shunt and provided visualization for surgical approach. This was determined most appropriate between the left medial and quadrate lobes of the liver.

8. Treatments administered/procedures performed: A 9mm Amyloid ring and key was placed around the shunt once surgically accessed and freed from surrounding connective tissue to the liver. A concurrent liver biopsy was performed and is pending histopathology. Intraoperatively, a temporary total ligation was performed to determine the necessity of the amyloid ring. It was determined that the portal pressures were too high with total ligation. This was determined by assessing the increase in motility of the intestines and force of vessel pulsation with the ligation in place.

9. Outcome/progress (if applicable): The amyloid ring is slow-closing and will progressively close over the next month or so. Xxxx will be monitored closely during this time, as there are concerns over portal hypertension or formation of acquired shunts. While generally positive in the long-term, if these complications do not occur over the next few months, there is always a concern that acquired shunts may form over time. In the meantime, Xxxx will remain on levetiracetam for two weeks, and lactulose and metronidazole for two months following the procedure, in hopes of helping her transition back to life as a puppy and decrease the accumulation of ammonia within her system.

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.