Preoperative training of pigs used for kidney transplantation research

The use of pigs as a preclinical model has increased dramatically the last decades. The specie´s unique anatomy and physiological features make it an appropriate transplantation study model for humans. In human medicine, kidney transplants have been established as the best and most cost-effective treatment for people with end-stage renal failure. To improve the outcome of renal transplantation in humans, the graft survival rate needs to be improved and an animal model is essential for this research. However, information regarding preoperative training to allow for stress- and pain-free repeated blood sampling as well as blood sampling techniques and measurement of the urine volume postoperatively to kidney transplantation is limited. Eight Swedish high-health domestic pigs were included in a training program in which touching and brushing the ears, ultrasound of the urinary bladder and physical examinations were performed for 15 minutes per pig every day for two weeks before transplantation surgery. Six of eight pigs underwent kidney transplantation and insertion of a catheter in the auricular vein with the Seldinger technique. After surgery, the pigs were kept for five days and blood sampling and ultrasound of the urinary bladder were performed daily. The effect of the preoperative training on postoperative examinations were evaluated. The transplantation surgery and the anaesthesia were successful and the pigs recovered well after surgery. The training period of two weeks was sufficient to enable blood sampling and ultrasound examination of the urinary bladder without restrain. Furthermore, placement of a catheter with the Seldinger technique in the auricular vein was successful and withdrawal of blood was possible in four out of six pigs for five days post-surgery. In conclusion this study shows that the pig can be trained preoperatively to accept interventions and measurements postoperatively, which makes the pig a suitable animal model in transplantation studies.Nyttjande av grisen som preklinisk modell har ökat markant de senaste decennierna. Djurslagets unika anatomi och fysiologi gör den till en lämplig modell för människan i transplantationsstudier. Inom humanmedicinen har njurtransplantationer blivit den bästa och mest kostnadseffektiva behandlingen för människor som drabbats av njursvikt. För att resultatet efter transplantationen ska kunna förbättras, behöver överlevnaden av transplantatet bli bättre. I dessa studier är en djurmodell oumbärlig. Information gällande preoperativ träning för att kunna utföra stress- och smärtfri upprepad blodprovs tagning och mätning av urinvolymen postoperativt till njurtransplantation är begränsad. Åtta svenska SPF grisar var inkluderade i ett träningsprogram där t.ex. klappa och borsta öronen, ultraljudsundersökning av urinblåsan och klinisk undersökning tränades i 15 minuter per gris, varje dag, i två veckor före transplantationskirurgi. Sex av åtta grisar genomgick njurtransplantation och kateterisering i auricularvenen med Seldingers teknik. Efter kirurgin utfördes blodprovstagning och ultraljudsundersökning av urinblåsan varje dag under fem dagar. Effekten av den preoperativa träningen på de postoperativa interventionerna utvärderades. Transplantationskirurgin och anestesin förlöpte utmärkt och grisarna återhämtade sig bra efter kirurgin. Den två veckor preoperativa träningen var tillräcklig för att möjliggöra blodprovstagning och ultraljudsundersökning av urinblåsan postoperativt utan stress för djuren. Därutöver var kateteriseringen i auricularvenen med Seldingers teknik tillfredställande och blodprovstagning var möjlig i fyra av sex grisar i fem dagar efter kirurgin. Resultatet visar att grisar kan tränas preoperativt för att acceptera interventioner och mätningar postoperativt, vilket gör grisen till en lämplig djurmodell i transplantationsstudie

A battery-less implantable glucose sensor based on electrical impedance spectroscopy

The ability to perform accurate continuous glucose monitoring without blood sampling has revolutionised the management of diabetes. Newer methods that can allow measurements during longer periods are necessary to substantially improve patients' quality of life. This paper presents an alternative method for glucose monitoring which is based on electrical impedance spectroscopy. A battery-less implantable bioimpedance spectroscope was designed, built, and used in an in vivo study on pigs. After a recovery period of 14 days post surgery, a total of 236 subcutaneous bioimpedance measurements obtained from intravenous glucose tolerance tests, with glucose concentration ranges between 77.4 and 523.8 mg/dL, were analyzed. The results show that glucose concentrations estimated by subcutaneous bioimpedance measurements correlate very well to the blood glucose reference values. The pigs were clinically healthy throughout the study, and the postmortem examinations revealed no signs of adverse effects related to the sensor. The implantation of the sensor requires minor surgery. The implant, being externally powered, could in principle last indefinitely. These encouraging results demonstrate the potential of the bioimpedance method to be used in future continuous glucose monitoring systems

Potential for residual contamination by Streptococcus equi subspp equi of endoscopes and twitches used in diagnosis of carriers of strangles

Background Endoscopic examinations are essential for diagnosis and treatment of strangles (S equi infection) in horses. However, even after disinfection, endoscopes may retain viable bacteria or bacterial DNA. Twitches are commonly used during endoscopic examinations and can thus also potentially transmit the organism to other horses.Objectives To evaluate the efficacy of different disinfectant methods to eliminate S equi from experimentally contaminated endoscopes and twitches and the effectiveness of field disinfection of endoscopes used in sampling carriers of S equi.Study design Experimental contamination and observational field study.Methods One endoscope and 30 twitches were contaminated with standardised S equi broth solutions. The endoscope was disinfected following three protocols using various disinfectants for manual disinfection. A fourth protocol used an automated endoscope reprocessor (AER). The twitches (n = 30) were disinfected following eight different disinfecting protocols. Three endoscopes used in sampling for silent carriers were disinfected following a field-based protocol. After each protocol the endoscopes and twitches were sampled for S equi by culture and qPCR.Results Following experimental contamination all endoscope disinfection protocols, apart from 1/6 of the ethanol protocol were S equi culture negative. However, no endoscope disinfection protocol completely eliminated retention of S equi DNA. Field disinfection of endoscopes after sampling carriers yielded no culture positives and all but one (13/14) were qPCR negative. All twitches disinfected following experimental contamination were culture negative but sodium hypochlorite was the only disinfectant that completely eliminated detection of S equi DNA.Main limitations Experimental contamination may not reflect the numbers of S equi transferred to endoscopes or twitches during use on silent carriers and purulent secretions from infected horses may influence survival of S equi.Conclusions While most disinfection methods appear to ensure removal of cultivable S equi, residual DNA can remain on both endoscopes and twitches

Nursing and anaesthesia care of growing pigs

The overall aim of the present thesis was to improve the welfare of animals in research by refining the perioperative nursing and anaesthesia care of growing pigs in accordance with the 3Rs, replace, reduce and refine. Forty-six pigs were trained during a 14-day acclimatisation period to accept blood and urine sampling and ultrasound examination. A polymer coated catheter for repeated blood sampling from the jugular vein was assessed. The effects of zolazepam-tiletamine and medetomidine (ZTMe) was compared with midazolam, ketamine and fentanyl (MiKF) regarding the quality of induction and physiological variables in a subsequent total intravenous anaesthesia (TIVA) with MiKF. A combination of zolazepam-tiletamine, dexmedetomidine and butorphanol (ZTDeB) intended for short-term anaesthesia was evaluated and physiological responses and drug plasma concentrations were examined. An artificial intelligence (AI) technology based on image vision was adapted for monitoring of the activity prior to anaesthesia and post-anaesthesia during treatment with transdermal fentanyl or buprenorphine injections. Facial expression was scored and plasma concentrations of the drugs were analysed. The training enabled blood and urine sampling and ultrasound examination without restraints. It was possible to collect blood from the catheters for up to ten days. ZTMe had better results than MiKF in areas such as shorter induction time, better intubation scoring results and less adjustment and amount of TIVA required for up to six hours of TIVA. ZTDeB provided two hours of anaesthesia with stable physiological variables and spontaneous breathing. The plasma concentration profile of the drugs was in line with the duration of the effect. Measurement of activity in pigs with the AI technique was encouraging. Both opioids, at the doses used, resulted in plasma concentrations above the suggested therapeutic levels. Assessment of facial expressions was time consuming and several factors influenced the result. In summary, the results showed that nursing interventions, adjustment of anaesthesia techniques and the use of AI technology for the measurement of activity can contribute to stress-free handling and improved animal welfare in growing pigs according to the 3Rs

Correction: Rydén et al. Physiological and Clinical Responses in Pigs in Relation to Plasma Concentrations during Anesthesia with Dexmedetomidine, Tiletamine, Zolazepam, and Butorphanol. Animals 2021, 11, 1482

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Pancreatic perfusion and its response to glucose as measured by simultaneous PET/MRI

AIMS: Perfusion of the pancreas and the islets of Langerhans is sensitive to physiological stimuli and is dysregulated in metabolic disease. Pancreatic perfusion can be assessed by both positron emission tomography (PET) and magnetic resonance imaging (MRI), but the methods have not been directly compared or benchmarked against the gold-standard microsphere technique. METHODS: Pigs (n = 4) were examined by [15O]H2O PET and intravoxel incoherent motion (IVIM) MRI technique simultaneously using a hybrid PET/MRI scanner. The pancreatic perfusion was measured both at basal conditions and after intravenous (IV) administration of up to 0.5 g/kg glucose. RESULTS: Pancreatic perfusion increased by 35%, 157%, and 29% after IV 0.5 g/kg glucose compared to during basal conditions, as assessed by [15O]H2O PET, IVIM MRI, and microspheres, respectively. There was a correlation between pancreatic perfusion as assessed by [15O]H2O PET and IVIM MRI (r = 0.81, R2 = 0.65, p < 0.01). The absolute quantification of pancreatic perfusion (ml/min/g) by [15O]H2O PET was within a 15% error of margin of the microsphere technique. CONCLUSION: Pancreatic perfusion by [15O]H2O PET was in agreement with the microsphere technique assessment. The IVIM MRI method has the potential to replace [15O]H2O PET if the pancreatic perfusion is sufficiently large, but not when absolute quantitation is required