Feeding management before gastrointestinal studies in pigs.

Pigs are used to model humans in gastrointestinal (GI) studies because of their comparable size, physiology and behaviour: both are monogastric omnivores. A porcine surgical model for testing novel, tethered ultrasound capsule endoscopes (USCE) requires a clean, motile small intestine. Recommendations for human GI tract preparation before the mechanically similar process of video capsule endoscopy describe using oral purgatives, while high-carbohydrate drinks are recommended before colorectal surgery. Reports of the GI preparation of pigs exist but lack technical details, that is, administration, efficacy and side effects. This report details feeding a high-energy liquid diet to 11 female pigs undergoing surgery and USCE which was readily accepted and easily administered, and which produced a clean, motile small intestine and caused no detectable physiological/behavioural abnormalities.

Risk factors for, frequency, and type of complications after temporary tube cystostomy in goats, sheep, and pigs.

OBJECTIVE: To describe risk factors for as well as type and frequency of complications, time to occurrence of complications, and mortality after temporary tube cystostomy alone or in combination with other surgical procedures, in goats, sheep, and pigs. STUDY DESIGN: Retrospective case series. ANIMALS: One hundred thirteen goats, eight sheep, and six pigs. METHODS: Medical records of goats, sheep, and pigs that underwent temporary tube cystostomy alone or in combination with urethrotomy at the Veterinary Medicine Teaching Hospital, University of California-Davis from January 1, 2007 to December 31, 2018 were reviewed. Signalment, presurgical and surgical procedures, urolith type and location, and postoperative complications and mortality were analyzed. In goats, logistic regression analysis was performed to determine association between the presence of complications or mortality as well as candidate predictor variables. RESULTS: Postoperative complications were reported in 54.9% (62/113) of goats, 37.5% (3/8) of sheep, and 50% (3/6) of pigs. The most frequent type of complication was reobstruction. Median (range) time to first complication was 171 days (1-2247) for goats. In sheep and pigs, the range for time to re-presentation for complications was 11 to 37 and 17 to 1182 days, respectively. Proportions of nonsurvivors after tube cystostomy were 48.4% (30/62) goats, 1/8 sheep and 2/6 pigs. No association between examined predictor variables and the occurrence of complications or mortality was detected. CONCLUSION: The risk of complications and mortality after temporary tube cystostomy was high, especially in goats. CLINICAL SIGNIFICANCE: Owners should be made aware of the high complication rate after temporary tube cystostomy alone or in combination with other procedures. Investigation of alternative approaches to manage obstructive urolithiasis in goats, sheep, and pigs should be considered.

Experimental assessment of three electrosurgical tissue-sealing devices in a porcine model.

Three electrosurgical tissue-sealing devices (EnSeal ETSDRC-01, LigaSure LS1500 and Thunderbeat TB-0535PC) were compared regarding sealing time (ST), maximum working temperature (WTmax) and the total (MTZtotal) as well as the collateral microscopic thermal injury zone (MTZcollat) using laparoscopic handpieces 5 mm in diameter on four types of tissue (liver, mesentery, cross striated muscle and spleen) in an in vivo porcine model. LigaSure had the lowest mean ST in spleen, mesentery, muscle and liver, followed by Thunderbeat and EnSeal with significant differences between all types of tissues and devices. The significantly lowest mean WTmax was obtained for EnSeal in mesentery, muscle and liver. LigaSure and EnSeal operated at the lowest temperature in spleen without a significant difference between them. Thunderbeat produced significantly higher temperature peaks in all cases. The lowest mean MTZtotal was caused by LigaSure and EnSeal in spleen, mesentery and muscle without significant differences between them, followed by the significantly higher values of Thunderbeat. Nevertheless, Thunderbeat produced the significantly lowest mean MTZtotal in the liver. EnSeal produced the lowest mean MTZcollat in the liver, followed by LigaSure and Thunderbeat showing significant differences. EnSeal and LigaSure produced the lowest mean MTZcollat in the spleen, mesentery and muscle without significant differences between them, followed by the significantly higher values of Thunderbeat. Based on the results of this study, Thunderbeat seems to be more invasive to tissue integrity (even without the activation of the ultrasonic scissor function) than EnSeal or LigaSure, that operate at lower temperatures and were found to cause negligible collateral thermal damage.

Characterization of the ablation zones produced by three commercially available systems from a single vendor for radiofrequency thermoablation in an ex vivo swine liver model.

BACKGROUND: Radiofrequency Ablation (RFA) is rarely performed in veterinary medicine. A rationale exists for its use in selected cases of canine liver tumours. RFA induces ablation zones of variable size and geometry depending on the technique used and on the impedance of the targeted organ. OBJECTIVES: (a) to describe the geometry and reproducibility of the ablation zones produced by three commercially available systems from a single company, using isolated swine liver parenchyma as a model for future veterinary applications in vivo; (b) to study the effects of local saline perfusion into the ablated parenchyma through the electrode tip and of single versus double passage of the electrode on size, geometry and reproducibility of the ablation zones produced. METHODS: Size, and geometry of ablation zones reproduced in six livers with one cooled and perfused (saline) and two cooled and non-perfused systems, after single or double passage (n = 6/condition), were assessed macroscopically on digitalized images by a blinded operator. Longitudinal and transverse diameters, equivalent diameter, estimated volume and roundness index were measured. Reproducibility was assessed as coefficient of variation. RESULTS AND CONCLUSIONS: Ablation zone reproducibility was higher when expressed in terms of ablation zone diameters than estimated volume. Local saline perfusion of the parenchyma through the electrode tip during RFA increased the ablation zone longitudinal diameter. Ablation zone estimated volume increased with saline perfusion only when double passage was performed. These data may provide useful information for those clinicians who intend to include RFA as an additive tool in veterinary interventional radiology.

Ultrasound-guided sciatic nerve block at the midthigh level in a porcine model: A descriptive study.

BACKGROUND AND OBJECTIVE: There are a growing number of porcine models being used for orthopaedic experiments for human beings. Therefore, pain management of those research pigs using ultrasound (US)-guided nerve block can be usefully performed. The aim of this study is to determine optimal US approaches for accessing and localizing the sciatic nerve at the midthigh level, a relevant block site for hindlimb surgery in female Yorkshire pigs. METHODS: As a first step, we dissected the intubated, blood-washed out pigs (n = 3) and confirmed the anatomical position of the sciatic nerve at midthigh level. After dissection, we found the sciatic nerve, connected with nerve stimulator, and checked the dorsiflexion or plantar flexion of the hindlimb. We matched the sciatic nerve location with the US image. After the pigs were euthanized, the neural structures of the sciatic nerve were confirmed by histological examination with H&E staining. In second step, a main US-guided sciatic nerve block study was done in the intubated, live pigs (n = 8) based on the above study. RESULTS: In lateral position, the effective US-guided nerve block site was about 6 cm from the patella crease level; immediately proximal to the bifurcation of the sciatic nerve into the tibial nerve and common peroneal nerve. The distal femur was selected as the landmark. There were no vessels or other nerves surrounding the sciatic nerve. The needle-tip was positioned less than 1 cm lateral from the distal femur and about 2 cm deep to skin. 'Donut sign' in US images was confirmed in all 16 nerves. CONCLUSIONS: Midthigh level sciatic nerve is located superficially, which enables nerve block to be easily performed using US. This is the first study to describe midthigh sciatic nerve block in the lateral position under US guidance in a porcine model from a clinical perspective.

Using multidimensional scaling in model choice for congenital oesophageal atresia: similarity analysis of human autopsy organ weights with those from a comparative assessment of Aachen Minipig and Pietrain piglets.

Swine models had been popular in paediatric oesophageal surgery in the past. Although being largely replaced by rodent models, swine experienced a revival with the establishment of minipig models. However, none of them has ever been investigated for similarity to humans. We conducted a pilot study to determine whether three-week old Pietrain piglets and three-month old Aachen Minipigs are suitable for experimental paediatric oesophageal atresia surgery. We tested the operation's feasibility, performed a necropsy, weighed organs, measured organ length and calculated relative weights and lengths, and measured laboratory parameters. We used multidimensional scaling to assess the similarity of the swine breeds with previously published human data. Pietrain piglets had a higher a priori bodyweight than Aachen Minipigs (Δ = 1.31 kg, 95% confidence interval (CI): 0.37-2.23, p = 0.015), while snout-to-tail length was similar. Pietrain piglets had higher absolute and relative oesophageal lengths (Δ = 5.43 cm, 95% CI: 2.2-8.6; p = 0.0062, q1* = 0.0083 and Δ = 11.4%, 95% CI: 5.1-17.6; p = 0.0025, q3* = 0.0053). Likewise, absolute and relative small intestinal lengths were higher in Pietrains, but all other parameters did not differ, with the exception of minor differences in laboratory parameters. Multidimensional scaling revealed three-week old Pietrain piglets to be similar to two-month old humans based on their thoracoabdominal organ weights. This result indicates three-week old Pietrain piglets are a suitable model of paediatric oesophageal atresia surgery, because clinically many procedures are performed at around eight weeks age. Three-month old Aachen Minipigs were more dissimilar to eight-week old humans than three-week old Pietrain piglets.

Gastrostomy tube placement via a laparotomic procedure in growing conventional piglets to perform multi-dose preclinical paediatric drug studies.

The use of juvenile conventional pigs as a preclinical animal model to perform pharmacokinetic (PK), pharmacodynamic (PD) and safety studies for the paediatric population is increasing. Repetitive oral administration of drugs to juvenile pigs is however challenging. A representative method which can be used from birth till adulthood is necessary. The current study presents the placement and use of a gastrostomy button in pigs with a weight ranging from 2.4 to 161 kg. The surgical placement was performed via a laparotomic procedure on, each time, 12 pigs (six male, six female) of 1 week, 4 weeks, 8 weeks and 6-7 months old. For every age category, eight pigs were part of a PK study with a non-steroidal anti-inflammatory drug (NSAID) and four pigs served as a control group. No severe complications were observed during surgery. The button remained functional for 10 days in 40 out of 48 pigs. No significant differences in body temperature or white blood cell count were observed during the trial. Three control pigs showed signs of inflammation indicating a NSAID might be warranted. Autopsy revealed minimal signs of major inflammation in the abdominal cavity or the stomach. A limited number of pigs showed mucosal inflammation, ulcers or abscesses in the stomach or around the fistula. These results indicate that the laparotomic placement of a gastrostomy button might be considered safe and easy in growing pigs to perform repetitive oral dosing preclinical studies. However, the method is not advised in pigs weighing more than 100 kg.

Effect of surgical or immune castration on postprandial nutrient profiles in male pigs.

To avoid boar taint before slaughtering, late castration by immunisation against gonadotrophin releasing hormone or immunocastration has been developed. The current study aimed at determining whether differences in feed efficiency between castrated male (CM), immune castrated (IM) and entire male pigs (EM) can be explained by differences in nutrient plasma profiles after a meal. In this study, 24 male pigs (n = 8/type) were enrolled between 14 to 19 weeks of age. Entire and IM pigs ate less and were more feed efficient than CM pigs (p < 0.05). The postprandial plasma profiles of glucose, insulin, urea and amino acids (AA) were determined before (d -6), just after (d 8) and well after (d 16) the decrease in testicular hormones in IM pigs. For each test day, pigs were fasted overnight and subsequently fed a small meal (400 g). On d -6, postprandial profiles of plasma glucose of IM pigs did not differ from the two other types of pigs. On d 8, EM pigs had a greater average plasma glucose concentration than IM and CM pigs (p < 0.05) but the profiles did not differ. On d 16, the differences between profiles of glucose suggest a lower clearance of glucose in EM compared with IM and CM pigs. Plasma insulin did not significantly differ between the three types. Plasma urea profiles did not differ between CM, EM and IC pigs on d -6 whereas CM pigs showed higher plasma urea concentrations than EM and IM thereafter (p < 0.01). Among AA, Lys plasma concentrations were greater in CM than in EM and IM pigs on d -6, d 8 and d 16 (p < 0.05), whereas on d 16 plasma Hypro concentrations were lower in CM than in EM and IM pigs (p < 0.05). The finding that plasma glucose profiles were modified by immunocastration much faster and earlier than urea and AA profiles, suggest that the decrease in testicular hormones impacted energy metabolism more rapidly than protein metabolism.

Ureterostomias cutânea e colônica em suínos: avaliação da exequibilidade das técnicas / Cutaneous ureterostomies in pigs: technical feasibility assessment

O aumento da expectativa de vida dos animais de companhia favorece a ocorrência de casos de câncer, como o de bexiga. O objetivo da presente pesquisa foi avaliar a exequibilidade da técnica de ureterostomia cutânea em suínos após a realização da cistectomia total, quando comparada à técnica de ureterostomia colônica, assim como detectar e caracterizar possíveis complicações transoperatórias. Foram utilizados 20 animais, distribuídos em dois grupos. Todos foram submetidos à cistectomia radical e, em seguida, à ureterostomia cutânea ou colônica. A exequibilidade das técnicas foi avaliada. Observou-se o tamanho da incisão, o tempo de diérese, de realização da derivação urinária e o tempo de síntese, estimou-se a perda sanguínea e o grau de dificuldade na realização dos procedimentos de preparo dos ureteres, o preparo do sítio de ureteroanastomose e a realização da ureteroanastomose em si. Os resultados indicam que a ureterostomia cutânea apresentou maior eficiência quando comparada à colônica nos quesitos perda de sangue, tamanho da incisão realizada e facilidade de realização da anastomose. Já a ureterocolostomia apresentou melhor resultado referente à execução do preparo ureteral. Assim, concluiu-se que ambas as técnicas podem ser indicadas como derivações urinárias viáveis e que a escolha dependerá de fatores intrínsecos ao cirurgião e ao paciente.(AU)

Increased life expectancy of pets favors the occurrence of cancer, such as the urinary bladder ones. The aim of this study was to evaluate the feasibility of cutaneous ureterostomy technique in pigs after the total cystectomy compared to the technique of colonic ureterostomy, as well as detect and characterize possible intraoperative complications. For that, 20 pigs were used, divided into two groups. All patients underwent radical cystectomy and then the cutaneous or colonic ureterostomies. The technical feasibility was assessed during the procedures. The procedures compared were: the incision size, dieresis time, realization of urinary diversion and the synthesis time. Also, the estimated blood loss and the degree of difficulty in performing the preparation procedures of the ureters, ureteroanastomose site preparation and ureteroanastomose itself were compared. The results indicate that performing cutaneous ureterostomy was better than the colonic ureterostomy in relation to blood loss, incision size, and anastomosis performance. In contrast, ureterocolonostomy showed better results on the implementation of ureteral preparation. Thus, it was concluded that both techniques can be indicated as viable urinary diversions and the choice will depend on factors intrinsic to the surgeon and the patient.(AU)

Meat quality traits in longissimus lumborum and gluteus medius muscles from immunocastrated and surgically castrated Iberian pigs.

This study analyzes quality traits of longissimus lumborum and gluteus medius in surgically castrated (SC) males, inmunocastrated (IC) males and IC female Iberian pigs reared in intensive conditions (n = 18/sex). Vaccination with Improvac® was applied at 18 and 26 weeks of age and slaughtering at 31 weeks. At such conditions, notable sex differences were found. Both muscles of IC males were less red (P < .01), longissimus had lower intramuscular fat (P < .01) and gluteus less Fe content (P < .01) than SC males and IC females. Loins from IC males also exhibited higher drip losses (2.7% at 24 h) than SC males (1.9%) and IC females (1.6%) (P < .001). Fatty acid composition of muscles differed among sexes, especially polyunsaturated fatty acids, which varied as follows: IC males > IC females > SC males in both muscles. It was concluded that meat quality traits differed between inmunocastrated and surgically castrated male Iberian pigs.

The inverse relationship between blood amylase and insulin levels in pigs during development, bariatric surgery, and intravenous infusion of amylase.

The purpose of this research is to explore the link between plasma amylase and insulin levels in growing pigs. Blood was obtained from piglets ranging in age from preterm (8 days to full gestation period), up to postnatal day 90 (2 months post-weaning) that underwent either duodenal-jejunal bariatric interposition surgery or a sham-operation. Plasma amylase activities in preterm and full-term neonates ranged between 500-600 U/L and were decreased by 50% two months post-weaning. Preprandial insulin and C-peptide levels in neonate piglets were not detectable, however they rose gradually after weaning. An increase in plasma amylase activity was observed in the young pigs that underwent duodenal-jejunum bypass (metabolic) surgery. The increase in blood pancreatic amylase activity after an intravenous amylase infusion lowered the subsequent glucose-stimulated insulin/C-peptide release. We suggest a role for blood amylase in the regulation of glucose homeostasis after observing high blood amylase levels in neonate pigs, in pigs that underwent metabolic surgery, and as a result of the reduced glucose-stimulated insulin response following intravenous amylase administration. Blood amylase level is a dynamic physiological parameter, which is not merely a consequence of exocrine pancreatic digestive enzyme production, but rather a regulated factor involved in glucose assimilation and prandial insulin regulation.

Ultrasound guided percutaneous common carotid artery access in piglets for intracoronary stem cell infusion.

In pigs, the deep location of the common carotid artery and overlying sternomastoideus muscle in the neck has led to the recommendation for a surgical cutdown for common carotid access, as opposed to minimally invasive techniques for vascular access. We sought to determine if direct percutaneous common carotid artery access in piglets is attainable. Seventeen piglets were anesthetized and intubated. Under two-dimensional and color flow Doppler ultrasound guidance, a 21 gauge needle was utilized to access the right common carotid artery. Following arterial puncture, the Seldinger technique was applied to place a 4 or 5 French introducer. Upon completion of cardiac catheterization with intracoronary stem cell infusion the introducer was removed and manual pressure was applied to prevent hematoma development. Successful access with an introducer was achieved in all 17 piglets. The average weight was 8.5 ± 1.7 kg. One piglet developed a hematoma with hemorrhaging from the catheterization site and was euthanized. This piglet was given bivalirudin for the procedure. After this incident, subsequent piglets were not given anticoagulation and no other complications occurred. Ultrasound guided percutaneous common carotid artery access in piglets is attainable in a safe, reliable, and reproducible manner when performed by microvascular experts.

Clinical prevalence and associated intraoperative surgical complications of reproductive tract lesions in pot-bellied pigs undergoing ovariohysterectomy: 298 cases (2006-2016).

To address the current dearth of clinically relevant publications regarding ovariohysterectomy (OVH) in the domestic pot-bellied pig (PBP), the present study aims to report prevalence of uterine lesions, intraoperative complications, and short and long-term survival in this species (n=298). Prevalence of lesions included uterine neoplasia 11.4 per cent (34/298), pyometra 1.6 per cent (5/298) and cystic endometrial hyperplasia 5 per cent (15/298). Pigs at least six years of age were statistically more likely to have a uterine lesion (less than P=0.001). Smooth muscle tumours represented the most frequent neoplasm. Haemorrhage was the most common intraoperative complication in 23 per cent (8/34) of pigs with neoplasia. Pigs without reproductive tract lesions were statistically more likely to survive to hospital discharge than those with lesions (P=0.001). Short-term survival, defined as survival to hospital discharge, of pigs with reproductive tract lesions was 89 per cent (48/54). Pigs with pyometra were least likely to survive to discharge 60 per cent (3/5). Long-term survival (≥1 year) was 93 per cent (14/15) for pigs with neoplasia. Practitioners should be aware of significantly higher rate of neoplastic and inflammatory diseases in PBP at least six years of age. To minimise morbidity and mortality in PBP undergoing OVH, the present study suggests the procedure should be performed prior to six years of age.

Electroencephalographic assessment of oral meloxicam, topical anaesthetic cream and cautery iron for mitigating acute pain in pigs (Sus scrofa) undergoing tail docking.

OBJECTIVE: To evaluate the efficacy of oral meloxicam, topical anaesthetic cream and cautery iron in mitigating acute nociceptive responses of pigs to tail docking. STUDY DESIGN: A prospective, randomized, controlled experimental study. ANIMALS: A total of 40 healthy Large WhitexLandrace pigs aged 21±1 days, weighing 6.1±0.9 kg. METHODS: Pigs were randomly assigned to one of four treatments (n=10 per treatment): CONTROL: docked using clippers without analgesia; MEL: docked using clippers after administration of oral meloxicam; EMLA: docked using clippers after application of topical anaesthetic cream; and CAUT: docked using a cautery iron without analgesia. Anaesthesia was induced and maintained with halothane in oxygen. Following induction, end-tidal halothane was stabilized at 0.95-1.05% and electroencephalograph (EEG) recording commenced. After 5 minutes of baseline data collection, tail docking was performed and recording continued for a further 10 minutes. The EEG summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT) were calculated for the baseline period and for consecutive 30-second intervals following docking. RESULTS: Following docking, F50 increased and PTOT decreased significantly in CONTROL and MEL pigs. EMLA pigs exhibited no change in any variable, whilst CAUT pigs exhibited a reduction in PTOT but no change in F50. F50 was higher in control pigs than in EMLA pigs 30-60 seconds after docking (p≤0.01). PTOT was lower in CONTROL than in EMLA pigs 30-90 seconds after docking (p<0.03) and in CAUT pigs 60 seconds after docking (p=0.01). CONCLUSIONS AND CLINICAL RELEVANCE: Prior application of EMLA cream abolished EEG indicators of nociception in pigs docked using clippers. Docking using a cautery iron without analgesia ameliorated EEG indicators of nociception, relative to using clippers without analgesia. Prior administration of EMLA cream or the use of cautery instead of clippers may reduce the acute pain experienced by pigs undergoing tail docking.

Electroencephalographic responses of anaesthetized pigs (Sus scrofa) to tail docking using clippers or cautery iron performed at 2 or 20 days of age.

OBJECTIVE: To compare electroencephalographic (EEG) responses of pigs to tail docking using clippers or cautery iron, performed at 2 or 20 days of age. STUDY DESIGN: Prospective, randomised controlled experimental study. ANIMALS: A total of 40 Large White x Landrace entire male pigs aged 2 (n=20) or 20 (n=20) days were randomly assigned to undergo tail docking using clippers or cautery iron. METHODS: Anaesthesia was induced and maintained with halothane delivered in oxygen. Following instrumentation, end-tidal halothane concentration was stabilised at 1.0±0.05%, and EEG recording commenced. After a 5 minute baseline period, tail docking was performed and recording continued for additional 10 minutes. EEG data were subjected to Fast Fourier transformation, yielding the summary variables median frequency (F50), 95% spectral edge frequency (F95) and total power (PTOT). Variables recorded during the baseline period were compared with those calculated at consecutive 15 second intervals following tail docking. RESULTS: Following tail docking, F50 decreased briefly but significantly in 2-day-olds, whereas 20-day-olds exhibited a sustained increase in F50 (p<0.05). Immediately after tail docking, F50 was overall lower in 2-day-olds than in 20-day-olds (p<0.05). F95 increased after docking in 20-day-olds docked using clippers (p<0.05) but did not change in 20-day-olds docked using cautery iron or in 2-day-olds docked using either method. Overall, F95 was lower in 2-day-olds than in 20-day-olds from 30 to 60 seconds after docking (p<0.05). PTOT decreased after docking in 20-day-olds (p<0.05) but did not change in 2-day-olds. Overall, PTOT was lower in 2- than in 20-day-olds during baseline and after tail docking (p<0.05). CONCLUSIONS AND CLINICAL RELEVANCE: These data suggest that tail docking using clippers is more acutely painful than docking using cautery iron and that docking within the first days of birth may be less acutely painful than docking at a later age.

Characterization of Normal and Freeze-Thawed Tissues in vitro Through The Ultrasonic Integrated Backscatter.

BACKGROUND: The ultrasound guidance of cryotherapy could be improved if changes of tissue characterization parameters during freezing could be used to monitor freezing patterns and estimate the postoperative effects after surgery. OBJECTIVE: The ultrasonic integrated backscatter analysis holds promise as an effective method for signal analysis and characterization of thawed tissues. MATERIALS AND METHODS: The ultrasonic integrated backscatter has been found to be an important parameter for describing the ultrasonic scattering and characterization of biological tissues. However, its potential values in the evaluation of cryosurgical effects of tissues reserved unclear so far. Here, we investigated the power spectrum of acoustic signal to estimate the ultrasound integrated backscatter in normal and freeze-thawed tissues on porcine livers in vitro. RESULTS: The experimental results carried out at 10 MHz using weakly focused pulse-echo signal element transducer indicated that the ultrasonic integrated backscatter in normal liver tissues is 31.3±4.6 whereas it is 44.2±6.5 in several pre-frozen and then thawed tissues. CONCLUSION: These results disclosed the good correlation between the ultrasonic integrated backscatter and microstructures of the normal or thawed tissues, and hence demonstrated that the power spectrum holds promise to be used as an effective method for the characterization of thawed tissues ultrasonic integrated backscatter, which might offer a potential pragmatic prospect for the practice of monitoring transition zone between frozen and unfrozen tissues during the surgical therapy, and evaluating postoperative effects.

Swine (Sus scrofa) as a Model of Postinfarction Mitral Regurgitation and Techniques to Accommodate Its Effects during Surgical Repair.

Mitral regurgitation (MR) is a common heart-valve lesion after myocardial infarction in humans. Because it is considered a risk factor for accelerated heart failure and death, various surgical approaches and catheter-based devices to correct it are in development. Lack of a reproducible animal model of MR after myocardial infarction and reliable techniques to perform open-heart surgery in these diseased models led to the use of healthy animals to test new devices. Thus, most devices that are deemed safe in healthy animals have shown poor results in human efficacy studies, hampering progress in this area of research. Here we report our experience with a swine model of postinfarction MR, describe techniques to induce regurgitation and perform open-heart surgery in these diseased animals, and discuss our outcomes, complications, and solutions.

A porcine model: surgical anatomy of the orbit for maxillofacial surgery.

Due to its similarity to humans, the pig has proven to be a suitable biomodel for both research purposes and for training medical professionals, particularly in surgical specializations. For example, new implant materials have been tested on pig jaws and pigs have also been used in the development of new surgical techniques. For optimizing the effectiveness of such research or training, detailed data on the anatomy of their particular features are needed. At present, however, only limited information related to surgical and imaging anatomy of the facial and orbital areas of the pig and its comparison to human structures from the experimental surgery point of view is available in the literature. The aim of this study was to obtain such data and to compare the morphological structures of the porcine and human orbital regions and to lay down the foundation for practical use in experimental surgery. Ten pig heads were examined using computed tomography (CT) and magnetic resonance imaging (MRI) and, subsequently, a dissection of the orbit was carried out. Attention was focused on the structure of the orbit (floor, rim and nerves) frequently affected by pathological processes in humans (such as trauma, infection or tumours) and which consequently are frequently the subject of maxillofacial surgery. The porcine orbit is suitable for use in experimental medicine. However, if used in experiments, its anatomical peculiarities must be taken into consideration. Our study presents a foundation of basic knowledge for researchers who plan to use the pig as a biomedical model to investigate alternative treatments in the head region.

Effect of three different bariatric obesity surgery procedures on nutrient and energy digestibility using a swine experimental model.

Morbid obesity is a worldwide health concern that compromises life quality and health status of obese human subjects. Bariatric surgery for treating morbid obesity remains as one of the best alternatives to promote excess weight loss and to reduce co-morbidities. We have not found studies reporting nutrients and energy balance considering digestibility trials in humans following surgery. The purpose of this study was to determine protein, lipid, fiber, energy, calcium, and phosphorous digestibility in a swine model that underwent ileal transposition (IT), sleeve gastrectomy with ileal transposition (SGIT), Roux-en-Y gastric bypass (RYGBP), and with sham operated animals (SHAM). Thirty-two pigs were randomly assigned to four laparoscopic procedures: IT (n = 8), RYGBP (n = 8), SGIT (n = 8), and Sham-operated pigs (n = 8). From day 0 postsurgery to 130, pigs were weighed monthly to determine live weight and weight gain was calculated for each month postsurgery until day 130. Food intake in a metabolic weight basis was calculated by measuring ad libitum food intake at day 130. Swine were fitted into metabolic crates to determine digestibility coefficients of dry matter, protein, fat, fiber, ash, energy, calcium, and phosphorous from day 130. A one-way ANOVA and Student-Newman-Keuls were used to detect differences in weight, food intake, and digestibility coefficients. Digestibility values for dry matter, fiber, phosphorus, and energy showed no differences among groups (P > 0.05). However, significant differences (P ≤ 0.05) were encountered among groups for fat, protein, ash, and calcium digestibilities. The RYGBP procedure, when applied to the pig model, significantly reduced calcium, fat, and ash digestibility, which did not occur with SGIT or IT procedure, when compared with Sham-operated animals.

Minimal portal vein stenosis is a promising preconditioning in living donor liver transplantation in porcine model.

BACKGROUND & AIMS: The main hindrance in promoting living donor liver transplantation remains the morbi-mortality risk for the donor. Considering the opposed remodeling influence of portal and hepatic artery flows, our working hypothesis was to identify a lobar portal vein stenosis capable of inducing a contralateral liver mass compensatory enlargement, without the downstream ipsilateral atrophic response. METHODS: Twenty-four pigs entered this study. Six of them were used to establish hemodynamic changes following a progressive left portal vein (LPV) stenosis, in blood flow, pressure and vessel diameter of the LPV, main portal vein and hepatic artery. Sixteen pigs were divided into 4 groups: sham operated animals, 20% LPV stenosis, 50% LPV stenosis, and 100% LPV stenosis. Daily liver biopsies were collected until post-operative day 5 to investigate liver regeneration and atrophy (Ki67, STAT3, LC3, and activated caspase 3) according to the degree of LPV stenosis. Finally, changes in liver volumetry after 20% LPVS were investigated. RESULTS: A 20% LPV stenosis led to dilatation of the hepatic artery and a subsequent four-fold increase in hepatic arterial flow. Concomitantly, liver regeneration was triggered in the non-ligated lobe and the cell proliferation peak, 5 days after surgery, was comparable to that obtained after total LPV ligation. Moreover, 20% LPV stenosis preconditioning did not induce left liver atrophy contrary to 50 and 100% LPV stenosis. CONCLUSIONS: A 20% LPV stenosis seems to be the adequate preconditioning to get the remnant liver of living donor ready to take on graft harvesting without atrophy of the future graft.