Laboratory Pigs Research Articles

Are neuromuscular blocking agents still being misused in laboratory pigs? (Preliminary Report)

Are neuromuscular blocking agents still being misused in laboratory pigs? (Preliminary Report)

Short Immobilization in a Sling Does Not Lead to Increased Salivary Cortisol Levels in Pigs

The goal of the present study was to evaluate the potential stress developed in farm hybrid pigs and miniature laboratory pigs briefly restrained in a sling, by measuring salivary cortisol levels. The study was performed in 20 healthy pigs grouped into three groups: group HYB-F: hybrid female pigs (n = 12), housed at the CREBA facility (Lleida, Spain); group MIN-F: Specipig® miniature female pigs (n = 4), housed at the CREBA facility; group MIN-M: Specipig® miniature male pigs (n = 4), housed at the Almirall facility (Barcelona, Spain). Upon arrival, the animals were enrolled in a social habituation and training program, which included habituation to a restraint sling. The sling was a stainless steel structure with a canvas hammock which had four openings for placing the animal’s feet. The assessment of stress levels in the sling was carried out by measuring cortisol levels in saliva samples. Five saliva samples were collected from each animal over 4 days: Sample 1 (basal sample): taken after animals perceived the presence of the technicians in the pen; Sample 2: taken after animals saw the sling in the pen; Sample 3: taken when animals were in the sling; Sample 4: taken 1 min after the previous one; Sample 5: taken after animals were released back on the floor. In group HYB-F, five animals (5/12) showed strong resistance and could not be restrained in the sling on at least one day. All animals in the groups of miniature pigs could be restrained on all the days. Within each group, the manipulation phase did not affect salivary cortisol levels. Likewise, salivary cortisol levels did not change significantly across days in either group. In conclusion, salivary cortisol levels did not increase when pigs were lifted and briefly restrained in the sling, even though some of them (in particular, the hybrid pigs) showed apparent signs of stress. The lack of correlation between such apparent stress and salivary cortisol levels might be because the vocalizations and movements were not really signs of stress, but simply a way of releasing discomfort, learned in the process of socialization and habituation. In light of this unexpected conclusion, further studies are needed to collect other physiological and behavioral data to clarify what actually happens when pigs are restrained in a sling.

Animal model of polytrauma for surgical training

Introduction: The aim of this study was to develop a training program for surgeons that would enable them to improve their practical skills using an animal model of polytrauma. Methods: Injury to the stomach, small and large bowel as well as spleen and liver injury were caused laparoscopically, and tension pneumothorax was induced thoracoscopically, in 60 laboratory pigs. A thus obtained polytrauma model was then used for the training of examination processes according to ATLS (advanced trauma life support) principles and of the treatment protocol according to DCS (damage control surgery) principles. Less experienced surgeons (N=10) completed a total of 4 training sessions, and experienced surgeons with postgraduate certification in surgery (N=10) performed 2 treatments. The relative training benefit was subsequently assessed by comparing the first and the last attempt. Furthermore, the absolute benefit of training for the beginners (novice trainees) was evaluated by comparing their last attempt with the first attempt of experienced surgeons. Results: The beginners (less experienced surgeons) showed an improvement (first vs fourth attempt) in all parameters except bowel injury management and laparotomy closure time. Based on the comparison of the experienced surgeons’ first attempt and the beginners’ first attempt, the beginners performed significantly worse in all parameters except the two mentioned above. Average total blood loss was also higher in the beginners’ group – 2531 (±661.1) g vs 1189 (±509.5) g in the experienced surgeons’ group (p<0.001). Conclusion: A novel animal model of polytrauma that can be used for the training of life threatening injury management was developed and validated in the study. The beginners improved significantly in all parameters after the training. However, longer training would be required to achieve results comparable to those of experienced surgeons.

Are slaughterhouse-obtained livers suitable for use in ex vivo perfusion research?

The success of the ex vivo machine perfusion of pig livers used for preclinical research depends on organ quality and availability. In this study, we investigated whether livers obtained from slaughterhouses are suitable and equivalent to livers obtained from laboratory pigs. Livers were obtained from slaughterhouse pigs stunned by electrocution or CO2 inhalation and from laboratory pigs. For the latter group, 45 minutes of warm ischemia was mimicked for a subgroup, ensuring a valid comparison with slaughterhouse-derived livers. Livers from CO2-stunned pigs showed lower indocyanine green clearance and bile production, higher blood lactate and potassium concentrations, and higher alanine aminotransferase activities than electrically stunned pigs. Furthermore, livers from electrically stunned pigs, and livers from laboratory pigs, subjected or not to warm ischemia, showed similar performance in terms of perfusion and metabolism. For an ex vivo liver model generated using slaughterhouse pigs, electrical stunning is preferable to CO2 stunning. Livers from electrically stunned slaughterhouse pigs performed similarly to laboratory pig livers. These findings support the use of livers from electrically stunned slaughterhouse pigs, which may therefore provide an alternative to livers obtained from laboratory pigs, consistent with the principle of the 3Rs.

Blood metabolic and physiological profiles of Bama miniature pigs at different growth stages

BackgroundBama miniature pigs aged between six (6 M) and twelve months (12 M) are usually used in human medical research as laboratory pigs. However, the difference in serum metabolic profiles from 6 to 12 M-old pigs remains unclear. This study aimed to identify the metabolic and physiological profiles present in the blood to further explain changes in Bama miniature pig growth. We collected blood samples from 6 M-, eight-month- (8 M-), ten-month- (10 M-), and 12 M-old healthy Guangxi Bama miniature pigs. A total of 20 blood physiological indices (BPIs) were measured: seven for white blood cells, eight for red blood cells, and five for platelet indices. Liquid chromatography and mass spectrometry-based non-targeted metabolomic approaches were used to analyze the difference in metabolites. The associations between the differences were calculated using Spearman correlations with Benjamini–Hochberg adjustment. The 100 most abundant differential metabolites were selected for analysis of their metabolic profiles.ResultsThere were no significant differences in BPIs at different ages, but the mid cell ratio and red blood cell number increased with age. Seven BPIs in Bama miniature pigs were closer to human BPIs than to mouse BPIs. A total of 14 and 25 significant differential metabolites were identified in 6 M vs. 12 M and 8 M vs. 12 M, respectively. In total, 9 and 18 amino acids and their derivatives showed significantly lower concentrations in 6 M- and 8 M-old pigs than in 12 M-old pigs. They were identified as the core significantly different metabolites between the age groups 6 M vs. 12 M and 8 M vs. 12 M. Half of the enriched pathways were the amino acids metabolism pathways. The concentration of six amino acids (dl-tryptophan, phenylacetylglycine, muramic acid, N-acetylornithine, l(−)-pipecolinic acid, and creatine) and their derivatives increased with age. A total of 61 of the top 100 most abundant metabolites were annotated. The metabolic profiles contained 14 amino acids and derivatives, six bile acids and derivatives, 19 fatty acids and derivatives, and 22 others. The concentrations of fatty acids and derivatives were found to be inversely proportional to those of amino acids and derivatives.ConclusionThese findings suggest high levels of MID cell ratio, red blood count, and amino acids in 12 M-old pigs as indicators for improved body function over time in Bama miniature pigs, similar to those in human development. This makes the pig a more suitable medical model organism than the mouse. The results of this study are limited to the characteristics of blood metabolism in the inbred Bama miniature pigs, and the effects of impacting factors such as breed, age, sex, health status and nutritional level should be considered when studying other pig populations.

Identification and pathogenicity of hepatitis E Virus from laboratory Bama miniature pigs

BackgroundHepatitis E virus (HEV) genotypes 3 and 4 are zoonotic. In this study, HEV infection in laboratory Bama miniature pigs in Sichuan Province of China was investigated. Firstly, one hundred rectal swabs were collected for HEV RNA testing, and chose positive samples for sequence analysis. Concurrently, for pathogenicity study, six healthy Bama miniature pigs were randomly divided into two groups of 3 pigs each. A total of 500 μL of HEV stock (positive fecal samples identified in this study) was inoculated intravenously into each pig in the experimental group, and the three pigs in the other group served as negative controls. Serum and fecal samples were collected at 1 to 10 weeks post-inoculation (wpi) for alanine aminotransferase (ALT) levels, anti-HEV antibodies and HEV RNA detection, respectively. During necropsies, liver lesions and HEV antigen in liver were observed at 10 wpi.ResultsThe rate of fecal sample HEV RNA-positivity was 12% (12/100). Sequence comparisons indicated that partial ORF1 and ORF2 gene sequences of this isolate shared highest identities with corresponding sequences of genotype 4a HEV isolates (81.4%-96.1% and 89.9%-97.1%, respectively). Phylogenetic tree analysis further demonstrated that sequences of this isolate clustered together with sub-genotype 4a HEV isolate sequences. Experimentally, the pathogenicity of Bama miniature pigs infected with this isolate exhibited viremia, fecal virus shedding, seroconversion, ALT level increasing, liver lesions and HEV antigen in liver.ConclusionsThis is the first study to confirm that HEV is currently circulating in laboratory Bama miniature pigs in China and this isolate can successfully infect Bama miniature pigs experimentally. More importantly, this study suggested HEV screening of laboratory pigs should be conducted to prevent research personnel from acquiring zoonotic HEV infections.

Inulin Clearance During Ex vivo Normothermic Machine Perfusion as a Marker of Renal Function.

Normothermic machine perfusion (NMP) offers a unique opportunity to objectively assess donor organ quality. This study describes the evaluation of inulin clearance as a potential marker for the ex vivo function of porcine kidneys during NMP. The function assessment was performed in both kidneys from slaughterhouse pigs (n = 20) and kidneys from pigs in a laboratory setting (n = 28). The kidneys were exposed to different warm ischemia times (WIT). After a period of static cold storage, the kidneys underwent a 4-hour NMP with autologous whole blood. Inulin clearance, hemodynamic parameters, and urine output were measured. Based on the inulin excretion behavior laboratory pig kidneys were assigned to three classes (functional, limited functional, and nonfunctional), slaughterhouse pig kidneys to two classes (limited functional and nonfunctional), respectively. Contrary to the marginal kidneys of the slaughterhouse pigs, the functional variation of kidneys of the laboratory pigs was associated with the WIT. A correlation between functional kidneys and a WIT less than 25 min was shown. Because none of the slaughterhouse pig kidneys could be assigned to the functional class, only the laboratory pig kidneys were used for examinations with functional markers. Renal blood flow and urine output during NMP correlated significantly ( p < 0.01) with ex vivo kidney function. This study demonstrated that inulin is a marker of high quality for the evaluation of suggested kidney function after NMP with whole blood. Furthermore, surrogate markers measured during NMP can be used to describe and predict the physiologic behavior of kidneys before transplantation.

Transition of Farm Pigs to Research Pigs using a Designated Checklist followed by Initiation of Clicker Training - a Refinement Initiative.

Implementation of 3R initiatives is important. To refine the life of laboratory pigs, we focused on the time period prior to inclusion of animals in experiments. We improved the checklist during the development. By using the checklist each individual pig's progress was documented. This aids the caretakers so they remain focused on the actions necessary to socialize the animals and limit the animal's stress and anxiety level. During this phase, the pigs become calm and ready to commence additional clicker training to further limit stress during the experimental period. The pigs will readily allow basic outcome measures to be collected without sedation or fixation. The protocol is divided in two. First the transition phase that begins as the pigs arrive at the research facility. Introducing treats and gradually closer contact to the caretakers are the first steps. Then, the caretaker introduces actions to be able to touch the head and hind, to mimic e.g. manipulating the ear to take a blood sample or the hind to obtain a rectal temperature. A strong foundation is established in the animal-caretaker relationship and this swiftly minimizes the stress the pigs express after arrival. Secondly, the positive reinforcement training commences to teach the animal how to carry out more complex tasks without becoming stressed. A clicker is introduced as a secondary reinforcer. Time, structure, education and thorough communication seem to be the most important criteria to succeed in the application of this protocol. In addition to having calm and compliant pigs, the caretakers report that they enjoy the focus they are allowed to give each individual pig, adding to their overall job satisfaction. Having caretakers with a strong commitment, and a focus on the transition progress and welfare of each pig, additionally strengthens the department's Culture of Care.

Экспериментальное исследование способа ушивания лапаротомной раны сетчатой нитью

Aim. Development of an alternative to preventive prosthetics method of primary closure of a laparotomy wound, superior in morphological and physical properties to the method of closure with traditional suture materials. Materials and Methods. The team of authors developed a method of laparorrhaphy, where the white line of the abdomen is sutured first with strengthening sutures with a mesh thread in places of highest tension, and then a continuous suture is applied. The effectiveness of this variant of wound closure was studied in a cadaver experiment and on tissues of laboratory pigs. In the course of the cadaver experiment, in 10 corpses of both genders a midline laparotomy was performed with suturing of the white line of the abdomen by the above-described technique with creation of intra-abdominal hypertension up to 140 mm Hg using a device designed for this. In the course of the experiment on animals, in 8 pigs under general anesthesia upper-median laparotomy up to the peritoneum 10-12 cm long was performed. The white line of the abdomen was sutured using the above-described technique with a mesh thread in the lower part of the wound. The upper part of the wound was closed with a checkerwise-reinforcing suture. At the second stage of the experiment, on the 14th day from the moment of the first operation, all animals were reoperated. A macroscopic assessment of the wound process was performed. Then the sutured sections of the aponeurosis were excised and subjected to strain gauge examination on an electronic dynamometer. For comparison, a similar study was carried out on an intact aponeurosis. Results. In the course of studies carried out on corpses, no cases of suture failure with the underlying created intra-abdominal hypertension were noted. The tensometry of the studied sutures proved that the initial strength of the reinforcing suture made of «mesh thread» was higher than that of one checker wise-reinforcing suture (tCt=27.053±0.745; p&lt;0.01) and two nodal sutures (tCt=-18.834±0.582; p&lt;0.01). On the 14th day, the strength of checkerwise-reinforcing suture was also lower than that of the reinforcing suture with a «mesh thread» (tCt=11.198±1.499; p&lt;0.01). Conclusions. The method of suturing with «mesh thread» provides greater strength compared to other types of sutures due to good conditions for even distribution of the load on all suture stitches and the formation of a strong scar in the future.

A Case Study on the Behavioural Effect of Positive Reinforcement Training in a Novel Task Participation Test in Göttingen Mini Pigs

Simple SummaryIn laboratory animal research, many procedures and tests will be stressful for the animals, as they are forced to participate. Training animals to voluntarily participate using reward-based training such as clicker training or luring may reduce levels of stress, and thereby increase animal welfare. Clicker training is traditionally used in zoos, aquariums, and with pets to train the animals to cooperate during medical procedures, whereas in experimental research, luring seems to be the preferred training method. This descriptive case study aims to present the behaviour of clicker trained and lured pigs when they are subjected to a potentially fear- and stress-evoking behavioural test—the novel task participation test—in which the pigs must walk a short runway with a novel walking surface. All eight trained pigs voluntarily participated and only one of the lured pigs showed a behaviour indicating decreased welfare. Hence, training pigs to cooperate during experimental procedures resulted in a smooth completion of the task with no signs of fear or anxiety in seven out of eight animals, and we thus suggest that training laboratory pigs prior to experimental procedures or tests should always be done to ensure low stress levels.In laboratory animal research, many procedures will be stressful for the animals, as they are forced to participate. Training animals to cooperate using clicker training (CT) or luring (LU) may reduce stress levels, and thereby increase animal welfare. In zoo animals, aquarium animals, and pets, CT is used to train animals to cooperate during medical procedures, whereas in experimental research, LU seem to be the preferred training method. This descriptive case study aims to present the behaviour of CT and LU pigs in a potentially fear-evoking behavioural test—the novel task participation test—in which the pigs walked a short runway on a novel walking surface. All eight pigs voluntarily participated, and only one LU pig showed body stretching combined with lack of tail wagging indicating reduced welfare. All CT pigs and one LU pig displayed tail wagging during the test, indicating a positive mental state. Hence, training pigs to cooperate during experimental procedures resulted in a smooth completion of the task with no signs of fear or anxiety in seven out of eight animals. We suggest that training laboratory pigs prior to experimental procedures or tests should be done to ensure low stress levels.

Mesenchymal stromal cell treatment of donor kidneys during ex vivo normothermic machine perfusion: A porcine renal autotransplantation study.

Normothermic machine perfusion (NMP) of injured kidneys offers the opportunity for interventions to metabolically active organs prior to transplantation. Mesenchymal stromal cells (MSCs) can exert regenerative and anti-inflammatory effects in ischemia-reperfusion injury. The aims of this study were to evaluate the safety and feasibility of MSC treatment of kidneys during NMP using a porcine autotransplantation model, and examine potential MSC treatment-associated kidney improvements up to 14days posttransplant. After 75min of kidney warm ischemia, four experimental groups of n=7 underwent 14h of oxygenated hypothermic machine perfusion. In three groups this was followed by 240min of NMP with infusion of vehicle, 10million porcine, or 10million human adipose-derived MSCs. All kidneys were autotransplanted after contralateral nephrectomy. MSC treatment did not affect perfusion hemodynamics during NMP or cause adverse effects at reperfusion, with 100% animal survival. MSCs did not affect plasma creatinine, glomerular filtration rate, neutrophil gelatinase-associated lipocalin concentrations or kidney damage assessed by histology during the 14days, and MSCs retention was demonstrated in renal cortex. Infusing MSCs during ex vivo NMP of porcine kidneys was safe and feasible. Within the short posttransplant follow-up period, no beneficial effects of ex vivo MSC therapy could be demonstrated.

NIRS-based monitoring of kidney graft perfusion.

IntroductionAcute early vascular complications are rare, but serious complications after kidney transplantation. They often result in graft loss. For this reason, shortening the diagnostic process is crucial. Currently, it is standard procedure to monitor renal graft perfusion using Doppler ultrasound (DU). With respect to acute vascular complications, the main disadvantage of this type of examination is its periodicity. It would be of great benefit if graft blood perfusion could be monitored continuously during the early postoperative period. It appears evident that a well-designed near infrared spectroscopy (NIRS) monitoring system could prove very useful during the early post-transplantation period. Its role in the immediate diagnosis of vascular complications could result in a significant increase in graft salvage, thus improving the patient’s overall quality of life and lowering morbidity and mortality for renal graft recipients. The aim of this study was to design, construct and test such a monitoring system.Materials and methodsWe designed a rough NIRS-based system prototype and prepared a two-stage laboratory experiment based on a laboratory pig model. In the first stage, a total of 10 animals were used to verify and optimize the technical aspects and functionality of the prototype sensor by testing it on the animal kidneys in-vivo. As a result of these tests, a more specific prototype was designed. During the second stage, we prepared a unique laboratory model of a pig kidney autotransplantation and tested the system for long-term functionality on a group of 20 animals. Overall sensitivity and specificity were calculated, and a final prototype was prepared and completed with its own analytic software and chassis.ResultsWe designed and constructed a NIRS-based system for kidney graft perfusion monitoring. The measurement system provided reliable performance and 100% sensitivity when detecting acute diminished blood perfusion of the transplanted kidneys in laboratory conditions.ConclusionThe system appears to be a useful tool for diagnosing diminished blood perfusion of kidney transplants during the early postoperative period. However, further testing is still required. We believe that applying our method in current human transplantation medicine is feasible, and we are confident that our prototype is ready for human testing.

The Blue-Blood Porcine Chest Wall: A Novel Microsurgery Training Simulator for Internal Mammary Vessel Dissection and Anastomosis.

Preparation of the internal mammary artery (IMA) is a critical step in autologous breast reconstruction. Intraoperatively, there is limited opportunity for residents to practice this skill. Porcine models provide highly realistic simulation for vascular surgery; however, use of live laboratory pigs is expensive, inconvenient, and offers limited opportunity for repetitive training. We aimed to develop an inexpensive and effective training model for IMA preparation. This article describes creation of a novel microsurgical model using cadaveric chest walls of Wisconsin Miniature Swine embedded in a modified mannequin thorax and augmented with a blue-blood perfusion system. Anatomic comparison: five porcine chest walls were dissected, and various anatomic measurements were made for anatomic comparison to existing human data in the literature. Model assembly: the chest wall is prepared by cannulating the proximal and distal ends of the internal mammary vessels with angiocatheters, which are then connected to the blue-blood perfusion system. The model is assembled in four layers including: (1) a mannequin thorax with a window removed to expose the first to fourth intercostal spaces, bilaterally, (2) a layer of foam simulating fat, (3) the perfused pig chest wall, and (4) a second mannequin shell placed posteriorly for support. The porcine chest walls are similar to humans with regards to vessel size and location. This model can be assembled quickly, with a one-time approximate cost of $55.00, and allows for six training sessions per specimen. The model allows residents to practice the key steps of IMA preparation including dissection, elevation of perichondria, and vascular anastomosis while working at a depth that closely simulates the human thorax. Continuous blue-blood perfusion provides immediate feedback on anastomosis quality. Overall, this novel model can provide inexpensive and realistic simulation of internal mammary vessel preparation and anastomosis.

Noninvasive, In-pen Approach Test for Laboratory-housed Pigs.

Traumatic brain injury (TBI) incidences have increased in both civilian and military populations, and many researchers are adopting a porcine model for TBI. Unlike rodent models for TBI, there are few behavioral tests that have been standardized. A larger animal requires more invasive handling in test areas than rodents, which potentially adds stress and variation to the animals' responses. Here, the human approach test (HAT) is described, which was developed to be performed in front of laboratory pigs' home pen. It is noninvasive, but flexible enough that it allows for differences in housing set-ups. During the HAT, three behavioral ethograms were developed and then a formula was applied to create an approach index (AI). Results indicate that the HAT and its index, AI, are sensitive enough to detect mild and temporary alterations in pigs' behavior after a mild TBI (mTBI). In addition, although specific behavior outcomes are housing-dependent, the use of an AI reduces variation and allows for consistent measurements across laboratories. This test is reliable and valid; HAT can be used across many laboratories and for various types of porcine models of injury, sickness, and distress. This test was developed for an optimized manual timestamping method such that the observer consistently spends no more than 9 min on each sample.

Pig Sample Handling in Research Laboratory Scale

The laboratory is a closed room or open room as a place for conducting experiments and research. One understanding when laboratory research is important to master is the management of samples, especially wet samples. One sample sample that requires special handling is a sample of pig. The management of samples, especially samples of unclean ingredients, do not yet have clear references so that they become a big dilemma and become uneasy with Muslims if they are not managed properly. The method used in writing this article is literature study, discussion and study. The results include laboratory layout, organizing laboratory management, and retrieval techniques as well as handling laboratory pig samples. In general, handling pig samples on a laboratory scale must be done with extra caution, detail, and aseptism

Behavioral Assessment of Vision in Pigs.

Swine (Sus scrofa) are often the 'gold standard' laboratory animal for ophthalmology research due to the anatomic and physiologic similarities between the porcine and human eye and retina. Despite the importance of this model, few tools for behavioral vision assessment in pigs are available. The aim of this study was to identify and validate a feasible and reproducible behavioral test to assess vision in a pig model of photoreceptor degeneration. In addition, a robust behavioral test will reduce stress and enhance enrichment by allowing animals opportunities for environmental exploration and by reducing the number of invasive experimental procedures. Two distinct behavioral approaches were tested: the obstacle-course test and temperament test. In the obstacle-course test, pigs were challenged (after an initial training period) to navigate a 10-object obstacle course; time and the number of collisions with the objects were recorded. In the temperament test, the time needed for pigs to complete 3 different tasks (human-approach, novel-object, and open-door tests) was recorded. The obstacle-course test revealed significant differences in time and number of collisions between swine with vision impairment and control animals, and the training period proved to be pivotal to avoid bias due to individual animal characteristics. In contrast, the temperament test was not altered by vision impairment but was validated to measure stress and behavioral alterations in laboratory pigs undergoing experimental procedures, thus achieving marked refinement of the study.

Specialist's training for laparoscopic surgery in Wet-lab educational operating theatre

To develop system for students training in laparoscopic surgery by using of Wet-lab educational operating theatre. We have launched laparoscopic surgery teaching program for students of Ryazan State Medical University. This system includes several stages. At the first stage professional selection was carried out on 'dry' laparoscopic simulators among III-IV-year students of medical faculty. So, 10 people were selected. The second stage included theoretical and practical parts consisting of development of basic laparoscopic skills on 'dry' simulators. 5 students who scored the maximum points were admitted to the next stage. The third stage is working in Wet-lab operating theatre with a mentor. There were 10 sessions on 10 laboratory pigs. Final stage of our study compares two groups of participants: main group - 5 students who underwent above-described program and control group of 5 residents without experience for laparoscopic operations. The participants of the main group had significantly higher OSATS score compared with another group (20 vs. 10; p<0.05). Movements effectiveness estimated by measuring of movements trajectory total length was also higher in main group than in control group (6 vs. 20; p<0.05). Experts' subjective assessment according to 10-point scale was also higher for students than for interns (9 vs. 5, p<0.05). Participants in the main group required significantly less time to complete the task compared with the control group (40 vs. 90 minutes, p<0.05). Our experience has shown that training system with Wet-lab operating theatre is effective for quick and efficient training of medical students in main laparoscopic procedures. In our opinion, introduction of students into 'advanced' surgery from early age will make it possible to get finally highly professional specialists.

Histopathological correlations to ureteral lesions visualized during ureteroscopy

PurposeTo correlate ureteral lesions visualized during ureteroscopy with histopathological findings.Materials and methodsUreteral access sheaths (UAS) sized 13/15 Fr. were inserted bilaterally in 22 laboratory pigs. During retraction of the UAS with a semirigid ureteroscope inside, ureteral lesions were evaluated and registered using the Post-ureteroscopic lesion scale (PULS). Ureters were excised in vivo between the uretero–pelvic junction and the uretero–vesical junction. Embedded in paraffin, 4-µm thick sections were step sectioned at 250–300 µm intervals and haematoxylin and eosin (HE) stained. Histopathological scoring of ureteral wall lesions was subsequently performed according to PULS.ResultsIn 72.1% of ureters, the highest histopathological score was at least 1 grade higher than the highest endoscopic PULS score. For 12 (27.9%) lesions, the difference was 2 scores higher, and for 1 (2.3%), it was 3 scores higher. The histopathological PULS grade was higher than the endoscopical PULS grade at all minimum, quartile, and maximum scores. There was a significant difference in the distribution of highest lesional scores between the endoscopic and histopathological PULS (p = 0.002). The calculated mean of the highest scores was 1.49 for endoscopic PULS and 2.51 for histopathological PULS (p < 0.0001).ConclusionHistopathological evaluation of ureteral wall lesions after UAS placement revealed a significantly higher degree of severity than observed endoscopically. Thus, endoscopy underestimated the histopathological extent of the lesion in the majority of cases.

In vivo images of the epidural space with two- and three-dimensional optical coherence tomography in a porcine model.

BackgroundNo reports exist concerning in vivo optical coherence tomography visualization of the epidural space and the blood patch process in the epidural space. In this study, we produced real-time two-dimensional and reconstructed three-dimensional images of the epidural space by using optical coherence tomography in a porcine model. We also aimed to produce three-dimensional optical coherence tomography images of the dura puncture and blood patch process.MethodsTwo-dimensional and three-dimensional optical coherence tomography images were obtained using a swept source optical coherence tomography (SSOCT) system. Four laboratory pigs were intubated and ventilated after the induction of general anesthesia. An 18-gauge Tuohy needle was used as a tunnel for the optical coherence tomography probe to the epidural space. Two-dimensional and three-dimensional reconstruction optical coherence tomography images of the epidural space were acquired in four stages.ResultsIn stage 1, real-time two-dimensional and reconstructed three-dimensional optical coherence tomography of the lumbar and thoracic epidural space were successfully acquired. In stage 2, the epidural catheter in the epidural space was successfully traced in the 3D optical coherence tomography images. In stage 3, water injection and lumbar puncture were successfully monitored in all study animals. In stage 4, 10 mL of fresh blood was injected into the epidural space and two-dimensional and three-dimensional optical coherence tomography images were successfully acquired.ConclusionsThese animal experiments suggest the potential capability of using an optical coherence tomography-based imaging needle in the directed two-dimensional and three-dimensional visualization of the epidural space. More investigations involving humans are required before optical coherence tomography can be recommended for routine use. However, three-dimensional optical coherence tomography may provide a novel, minimally invasive, and safe way to observe the spinal epidural space, epidural catheter, lumbar puncture hole, and blood patch.

Plasma concentrations of transdermal fentanyl and buprenorphine in pigs (Sus scrofa domesticus)

ObjectiveTo determine the absorption characteristics of fentanyl and buprenorphine administered transdermally in swine. Study designA randomized comparative experimental trial. AnimalsTwenty-four Yorkshire gilts weighing 27.8±2.2 kg (mean±standard deviation). MethodsAnimals were randomly assigned to different doses of transdermal patches (TPs) of fentanyl (50 μg hour−1, 75 μg hour−1 and 100 μg hour−1) or buprenorphine (35 μg hour−1 and 70 μg hour−1), once or twice. Thirteen blood samples were obtained for each TP applied. Plasma concentrations were determined, and the area under the curve, peak serum concentration (Cmax) and time to Cmax were calculated. ResultsFentanyl: Cmax was observed at different time points: for the first TP application: 30 hours for 50 μg hour−1, 6 hours for 75 μg hour−1 and 100 μg hour−1 patches; and for the second TP application: 30 hours for 50 μg hour−1 and 36 hours for 75 μg hour−1 patches. Buprenorphine: serum concentrations were not detected for the 35 μg hour−1 patch; Cmax was observed at different times for the 70 μg hour−1 patch: 18 hours (n = 1), 24 hours (n = 3), 30 hours (n = 1) and 42 hours (n = 1) after application of the first patch and 12 hours after the second patch. Conclusions and clinical relevanceA relevant serum concentration obtained with fentanyl TP dosed at 75 μg hour−1 or 100 μg hour−1suggests that TPs could represent an analgesia option for laboratory pigs weighing 25–30 kg. As concentrations of buprenorphine were variable, this study does not support the use of buprenorphine TPs in pigs. Consecutive fentanyl or buprenorphine TPs did not provide reliable serum concentrations. Further pharmacokinetic studies and analgesiometric tests in swine are needed to confirm the clinical adequacy of TPs.