Female Pigs Research Articles

The Evaluation of Intrarenal Pressure Using a Novel Single-Use Flexible Ureteroscope with Live Intrarenal Pressure Monitoring-An Experimental Study in Porcine Models.

(1) Background: This study aims to evaluate how different irrigation settings and the use of ureteral access sheaths (UASs) of varying sizes impact intrarenal pressure (IRP) during flexible ureteroscopy (fURS) procedures in pigs. (2) Methods: This study utilized three anesthetized female pigs. A novel flexible ureteroscope with the ability to continuously record live intrarenal pressure was used to perform ureteroscopy in different settings. Ureteroscopy was performed without UAS and with the use of 11/13 and 12/14 UAS at the ureteropelvic junction. Two different irrigation methods were employed for each parameter: one using gravity flow and the other using manual pumping with a commercial pump. IRP was also recorded with the presence of a laser fiber or lithotripsy basket. (3) Results: The recorded mean IRP during flexible URS without UAS was 28.25 (±11.2) under gravity irrigation; 35.46 (±10.08) under manual pumping; 22.5 (±3.05) and 30.75 (±5.79) with a laser fiber under gravity irrigation and manual pumping, respectively; and 16.45 (±1.27) and 17.27 (±3.69) with a lithotripsy basket under gravity irrigation and manual pumping, respectively. With an 11/13 UAS, the mean IRP was 15.41 (±8.57) and 19.33 (±4.26) under gravity and manual pumping irrigation, respectively; 14.56 (±2.50) and 18.64 (±5.13) with a laser in each irrigation setting, respectively; and 13.10 (±3.39) and 13.86 (±4.63) with a lithotripsy basket, respectively. With a 12/14 UAS, the mean IRP was 7.64 (±3.08) and 9.25 (±1.42) under gravity and manual pumping irrigation, respectively; 9.50 (±6.04) and 10.28 (3.46), respectively, in each setting when the laser fiber was used; and 5.32 (±1.57) and 6.26 (±1.79), respectively, when the lithotripsy basket was inserted. (4) Conclusion: Novel flexible ureteroscopes with integrated pressure sensors are both a feasible and reliable tool during fURS, giving the surgeon the ability to live-track the IRP. The results of the IRP measurements with and without UAS are in accordance with the current literature and exhibit a consistent pattern with previous studies.

Pharmacokinetics of single dose levobupivacaine after peri-incisional subcutaneous infiltration in anaesthetized domestic pigs.

Increasing use of pigs as models in translational research, and growing focus on animal welfare are leading to better use of effective analgesics and anaesthetics when painful procedures are performed. However, there is a gap in basic knowledge such as pharmacokinetics of different anaesthetics in these species. The main objective of our study was to determine the pharmacokinetics of levobupivacaine in domestic pigs. Twelve female grower pigs weighing 31.17 ± 4.6 kg were subjected to general anaesthesia and experimental surgery, at the end of which they received 1 mg/kg levobupivacaine via peri-incisional subcutaneous infiltration. Plasma samples were collected before administration of levobupivacaine and at 0.5, 1, 2, 4, 8, 12, 24 and 48 h thereafter. Concentrations of levobupivacaine were determined by liquid chromatography coupled with tandem mass spectrometry. Following single dose of levobupivacaine, all animals had measurable plasma concentrations 0.5 h after drug administration, with most peak concentrations observed at the 1-h time point. In all 12 animals, levobupivacaine was below the limit of quantification 48 h after drug administration. The mean maximum plasma concentration, area under the curve and half-life were determined to be 809.98 μg/l, 6552.46 μg/l h and 6.25 h, respectively. Plasma clearance, volume of distribution and weight-normalized volume of distribution were 4.41 l/h, 35.57 l and 1.23 l/kg, respectively. Peak plasma concentrations in our study were well below concentrations that were found to produce toxicity in pigs.

ALM Resuscitation With Brain and Multiorgan Protection for Far-Forward Operations: Survival at Hypotensive Pressures.

Non-compressible torso hemorrhagic (NCTH) shock is the leading cause of potentially survivable trauma on the battlefield. New hypotensive drug therapies are urgently required to resuscitate and protect the heart and brain following NCTH. Our aim was to examine the strengths and limitations of permissive hypotension and discuss the development of small-volume adenosine, lidocaine, and Mg2+ (ALM) fluid resuscitation in rats and pigs. For review of permissive hypotension, a literature search was performed from inception up to November 2023 using PubMed, Cochrane, and Embase databases, with inclusion of animal studies, clinical trials and reviews with military and clinical relevance. For the preclinical study, adult female pigs underwent laparoscopic liver resection. After 30 minutes of bleeding, animals were resuscitated with 4 mL/kg 3% NaCl ± ALM bolus followed 60 minutes later with 4 h 3 mL/kg/h 0.9% NaCl ± ALM drip (n = 10 per group), then blood transfusion. Mean arterial pressure (MAP) and cardiac output (CO) were continuously measured via a left ventricular pressure catheter and pulmonary artery catheter, respectively. Systemic vascular resistance (SVR) was calculated using the formula: 80 × (MAP - CVP)/CI. Oxygen delivery was calculated as the product of CO and arterial oxygen content. Targeting a MAP of ∼50 mmHg can be harmful or beneficial, depending on how CO and SVR are regulated. A theoretical example shows that for the same MAP of 50 mmHg, a higher CO and lower SVR can lead to a nearly 2-fold increase in O2 supply. We further show that in animal models of NCTH, 3% NaCl ALM bolus and 0.9% NaCl ALM drip induce a hypotensive, high flow, vasodilatory state with maintained tissue O2 supply and neuroprotection. ALM therapy increases survival by resuscitating the heart, reducing internal bleeding by correcting coagulopathy, and decreasing secondary injury. In rat and pig models of NCTH, small-volume ALM therapy resuscitates at hypotensive pressures by increasing CO and reducing SVR. This strategy is associated with heart and brain protection and maintained tissue O2 delivery. Translational studies are required to determine reproducibility and optimal component dosing. ALM therapy may find wide utility in prehospital and far-forward military environments.

In Vivo Testing of a Second-Generation Prototype Accessory for Single Transapical Left Ventricular Assist Device Implantation.

A new accessory was developed to allow implantation of left ventricular assist devices (LVADs) without requiring an anastomosis to the ascending aorta. The accessory combines the LVAD inflow and outflow into a dual-lumen device. Initial prototypes encountered reduced pump performance in vitro, but a second-generation prototype successfully addressed this issue. This feasibility study aimed to demonstrate the anatomic fit, safe implantation, and hemodynamic effectiveness of the LVAD with the accessory. The accessory was implanted in ten female pigs (104 ± 13 kg). Following sternotomy and apical coring under cardiopulmonary bypass, a balloon catheter was retrogradely inserted and exteriorized through the coring site, where it was inflated within the distal third of the outflow graft. It was utilized to pull the accessory's outflow across the aortic valve. After LVAD attachment, the catheter was removed. Echocardiography revealed no relevant valve regurgitation post-implantation. During ramp testing, pump flow increased from 3.7 ± 1.2 to 5.4 ± 1.2 L/min. Necropsy confirmed correct accessory placement in nine animals. No valve lesions or device thrombosis were observed. The accessory enabled LVAD implantation without compromising pump performance. Future work includes design refinements for implantation without cardiopulmonary bypass and long-term testing in a chronic heart failure model.

Digestive characterization and its relationship with digestibility, performance traits of local breed Mexican Cuino mini-pigs

The effect of sex on the characteristics of the digestive tract and its relationship with the apparent total tract digestibility (ATTD) and performance traits was studied in 14 Mexican Cuino (MC) mini-pigs averaging 57.2 ± 8.1 kg, fed ad libitum a diet based on sorghum and soybean meal. Nitrogen ATTD was significantly better in females than in castrated male pigs. A trend was found for the relative weight of the entire digestive tract to be heavier in castrated males than in female pigs. Large intestine contribution to total digestive tract weight was relatively high in both sexes, 48.7 and 50.8%, respectively, for castrated males and females. A significant, though not strong relationship between large intestine relative weight and ATTD of dry matter (DM) was observed. These results indicate that sex would appear to be a factor influencing digestive processes in MC mini-pigs.

Mild (34 °C) versus moderate hypothermia (24 °C) in a swine model of extracorporeal cardiopulmonary resuscitation

BackgroundThe role of hypothermia in post-arrest neuroprotection is controversial. Animal studies suggest potential benefits with lower temperatures, but high-fidelity ECPR models evaluating temperatures below 30 °C are lacking. ObjectivesTo determine whether rapid cooling to 24 °C initiated upon reperfusion reduces brain injury compared to 34 °C in a swine model of ECPR. MethodsTwenty-four female pigs had electrically induced VF and mechanical CPR for 30 min. Animals were cannulated for VA-ECMO and cooled to either 34 °C for 4 h (n = 8), 24 °C for 1 h with rewarming to 34 °C over 3 h (n = 7), or 24 °C for 4 h without rewarming (n = 9). Cooling was initiated upon VA-ECMO reperfusion by circulating ice water through the oxygenator. Brain temperature and cerebral and systemic hemodynamics were continuously monitored. After four hours on VA-ECMO, brain tissue was obtained for examination. ResultsTarget brain temperature was achieved within 30 min of reperfusion (p = 0.74). Carotid blood flow was higher in the 24 °C without rewarming group throughout the VA-ECMO period compared to 34 °C and 24 °C with rewarming (p < 0.001). Vasopressin requirement was higher in animals treated with 24 °C without rewarming (p = 0.07). Compared to 34 °C, animals treated with 24 °C with rewarming were less coagulopathic and had less immunohistochemistry-detected neurologic injury. There were no differences in global brain injury score. ConclusionsDespite improvement in carotid blood flow and immunohistochemistry detected neurologic injury, reperfusion at 24 °C with or without rewarming did not reduce early global brain injury compared to 34 °C in a swine model of ECPR.

Cross-seasonal and diurnal variation in physical contact between sub-adult pigs

Social touch is an important aspect of social relationships and has a major influence on development and health. However, in many species the occurrence and function of social touch is unknown. Pigs have frequent physical contact but this behaviour is largely unexplored. The aim of this study was to investigate the undisturbed variation in physical contact between pigs, and to assess diurnal and seasonal influences. A stable group of ten Puławska sub-adult female pigs was observed for 406 h across four seasons during the day and night, by continuous observations on an individual level (406 h / pig). They were housed indoors (112 m2 pen) on straw bedding. The ethogram distinguished the amount of surface contact between pigs when lying, the orientation to others, social nosing, other non-agonistic social behaviour and agonistic behaviours. Resting location within the pen was recorded 48 times per pig, and dominance relationships were calculated from agonistic interactions. Data were analysed with mixed models accounting for repeated observations. Pigs spent on average 40 % of their time lying in body contact, most often lying with their extremities in contact (71 %), followed by lying in partial body contact (16 %) or full body contact (13 %) and were frequently nosing the head and body of others. The duration of lying in any type of contact, as well as agonistic behaviour, was influenced by season, with the longest durations in autumn. In summer, the duration of partial body contact was lowest, but full body contact was unaffected by season. Nosing behaviour remained constant throughout the year. Pigs lay in contact more during the night, while showing more social behaviours during the day. Pigs mostly lay in nonparallel orientation or head-to-head, but clearly least in the head-to-tail orientation. Season influenced the frequency of lying head-to-head and head-to-tail, but not lying nonparallel. The coefficient of variation of the lying location was influenced by season. Allo-grooming, mounting, and nudging were shown infrequently and mostly by specific individuals. In conclusion, when at a large space allowance, pigs spend nearly half of their time in body contact, even during the higher temperatures in summer. This shows that social touch, including affiliative behaviour, has an important role in pigs’ social life, and remains largely unaffected by external influences.

Short cycles of remote ischemic preconditioning had no effect on tensile strength in small intestinal anastomoses: an experimental animal study

PurposeThis study aimed to investigate the effect of remote ischemic preconditioning (RIPC) on the healing of small intestinal anastomoses, evaluated by tensile strength and histologic wound healing on postoperative day 5. MethodsA total of 22 female pigs were randomized 1:1 into either an intervention or control group. The intervention group received 5 cycles of 3-minute ischemia followed by 3-minute reperfusion on the right forelimb. Two end-to-end anastomoses, a distal and a proximal, were created in the small intestine 30 and 60 min after RIPC, respectively. On postoperative day 5, the anastomoses were harvested and underwent a maximal anastomotic tensile strength (MATS) test (MATS 1–3) followed by histologic analyses. ResultsMATS 1, when a tear became visible in the serosa, was significantly increased in the proximal anastomoses of the RIPC group compared with the control group (4.91 N vs 3.83 N; P = .005). No other significant differences were found when comparing these 2 groups. ConclusionOur study showed no convincing results of RIPC on intestinal anastomotic healing to recommend its use in a general clinical setting. Further animal studies on RIPC’s effect after relative or absolute intestinal ischemia may be recommended.

Intramyocardial immunomodulation with human CD16+ monocytes to treat myocardial infarction in pig: a blind randomized preclinical trial.

Human CD16+ monocytes (hCD16+ Ms) have proangiogenic properties. We assessed the feasibility, safety and efficacy of hCD16+ Ms in a porcine model of myocardial infarction (MI). A total of 27 female Large White pigs underwent MI with reperfusion and cardiac magnetic resonance (CMR). Five days later, animals received intramyocardial injections of hCD16+ Ms in saline (n = 13) or saline only (n = 14). hCD16+ Ms were selected from leucocyte cones. Feasibility/safety endpoints included injury at injected sites, malignant arrhythmias, cancer, haematoma, left ventricular (LV) dilatation, troponin release and downstream organ injury. Co-primary efficacy outcome included LV scar and ejection fraction (LVEF) at 30-day post-injections by CMR. Immunohistochemistry included neo-angiogenesis, fibrosis, markers of myofibroblast and inflammation. Four animals were excluded before injections due to untreatable malignant arrhythmias or lung injury. Median cell number and viability were 48.75 million and 87%, respectively. No feasibility/safety concerns were associated with the use of hCD16+ Ms. The LV scar dropped by 14.5gr (from 25.45 ± 8.24 to 10.8 ± 3.4 gr; -55%) and 6.4gr (from 18.83 ± 5.06 to 12.4 ± 3.9gr; -30%) in the hCD16+ Ms and control groups, respectively (p = 0.015). The 30-day LVEF did not differ between groups, but a prespecified sub-analysis within the hCD16+ Ms group showed that LVEF was 2.8% higher and LV scar 1.9gr lower in the subgroup receiving a higher cell dose. Higher tissue levels of neo-angiogenesis, myofibroblast and IL-6 and lower levels of TGF-β were observed in the hCD16+ Ms group. The use of hCD16+ Ms in acute MI is feasible, safe and associated with reduced LV scar size, increased tissue levels of neo-angiogenesis, myofibroblasts and IL-6 and reduced pro-fibrotic TGF-β at 30-day post-injections. A higher cell dose might increase the LVEF effect while reducing scar size, but this warrants validation in future studies.

Penicillin concentrations in bone and subcutaneous tissue: A porcine microdialysis study comparing oral and intravenous treatment.

Penicillin is available in both an oral (penicillin V) and intravenous formulation (penicillin G), theoretically allowing for a safe transition between the two. However, the use of oral penicillin remains a topic of debate due to low and variable bioavailability. This study aimed to assess the time for which the free penicillin concentration exceeded targeted minimum inhibitory concentrations for Staphylococcus aureus and Streptococcus species (0.125, 0.25, and 0.5 mg/L) in cancellous bone and subcutaneous tissue after intravenous penicillin and oral penicillin administration. 12 female pigs (68-75 kg) were assigned, according to local standard clinical regimes, to either intravenous penicillin (1.2 g) or oral penicillin (0.8 g) treatment every 6 h over an 18 h period. Microdialysis catheters were placed for sampling in tibial cancellous bone and adjacent subcutaneous tissue. Data was dynamic/continually collected in the first dosing interval (0-6 h), simulating a prophylactic situation, and the third dosing interval (12-18 h), simulating a therapeutic setting. Plasma samples were collected for reference. For all investigated targets, intravenous treatment resulted in a longer mean time above relevant minimum inhibitory concentrations in cancellous bone during the first dosing interval, and in both cancellous bone and subcutaneous tissue during the third dosing interval compared to oral treatment. With clinically relevant dosing, intravenous penicillin provides superior exposure compared to oral penicillin in both a prophylactic and therapeutic setting.

Cull guinea pigs: carcass and non-carcass traits in males and females compared to their fattening counterparts.

Culling of guinea pigs can provide a large number of animals per year for meat production, but little information is available in the scientific literature on the carcass characteristics and non-carcass components of these animals. The objective of this study was to evaluate the carcass and non-carcass characteristics of cull guinea pigs in comparison to their fattening counterparts. Forty-eight fattening (3 months-age, 24 females and 24 males) and forty-eight cull (14 months-age, 24 females and 24 males) guinea pigs were slaughtered and carcass yield, linear measurements, tissular composition, and non-carcass components were evaluated. In general, cull guinea pigs had higher carcass, tissue, and non-carcass component weights. Cull male and both female guinea pig groups had similar carcass yields. Cull animals had higher carcass and hind leg lengths, lumbar and thoracic circumferences, and carcass compactness than their young counterparts. However, a sex effect was found for leg compactness depending on whether they were fattened or cull. Tissue percentages values were similar between fattening and culling animals of the same sex. However, females had a higher percentage of fat tissue than males. Fattening females had the best muscle to bone ratio, followed by cull males. The non-carcass elements were more represented in fattening animals than in culls, probably due to an allometric growth of the viscera in relation to the rest of the body. In commercial and cooking terms, this information is valuable for producers and researchers who need to understand the factors that influence carcass characteristics of guinea pigs.

Effect of Sex on Intestinal Microbial Metabolites of Hainan Special Wild Boars.

The intestinal microbiota and its metabolites are essential for the health and growth development of animals. Current research indicates that sex has a certain impact on the structure and function of the intestinal microbiota, but there are few reports on sex differences in intestinal microbiota metabolites, including those of castrated male animals. This study aimed to explore the impact of sex on the intestinal microbial metabolites of Hainan special wild boars (10 entire male pigs, 10 female pigs, and 10 castrated male pigs, denoted EM, FE, and CM, respectively) by employing non-targeted metabolomics and gas chromatography. A total of 1086 metabolites were detected, with the greatest number of differential metabolites observed between EM and FE (54 differential metabolites, including 18 upregulated and 36 downregulated metabolites), the fewest between CM and FE (7 differential metabolites, including 1 upregulated and 6 downregulated metabolites), and an intermediate number between CM and EM (47 differential metabolites, including 35 upregulated and 12 downregulated metabolites). Differential metabolites were involved in more pathways between EM and FE and between CM and EM, including amino acid metabolism and digestive system pathways, whereas differential metabolites were involved in the fewest pathways between CM and FE. Correlation analysis showed Ruminococcaceae UCG-009, uncultured_bacterium_o_SAR324_cladeMarine_group_B, and Candidatus Saccharimonas contributed to the production of metabolites such as trehalose, docosatrienoic acid, D(-)-beta-hydroxy butyric acid, and acetyl-DL-leucine. The levels of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid were significantly higher in EM than in FE, with CM falling between the two. Streptococcus, Lachnospiraceae_NK4A136_group and Rikenellaceae_RC9_gut_group showed a significant positive correlation with the production of short-chain fatty acids (SCFAs), while [Eubacterium]_coprostanoligenes_group, uncultured_bacterium_f_p-251-o5 and Ruminococcaceae_UCG-005 showed a significant negative correlation with the generation of SCFAs. This study provides foundational data and significant insights into precision feeding strategies for Hainan special wild boars of different sexes, as well as the study of sex differences in intestinal microbial metabolites in animals.

Gastric slow-wave modulation via power-controlled, irrigated radio-frequency ablation.

Recently, radio-frequency ablation has been used to modulate slow-wave activity in the porcine stomach. Gastric ablation is, however, still in its infancy compared to its history in the cardiac field, and electrophysiological studies have been restricted to temperature-controlled, non-irrigated ablation. Power-controlled, irrigated ablation may improve lesion formation at lower catheter-tip temperatures that produce the desired localized conduction block. Power-controlled, irrigated radio-frequency ablation was performed on the gastric serosal surface of female weaner pigs (n = 5) invivo. Three combinations of power (10-15 W) and irrigation settings (2-5 mL min-1) were investigated. A total of 12 linear lesions were created (n = 4 for each combination). Slow waves were recorded before and after ablation using high-resolution electrical mapping. Irrigation maintained catheter-tip temperature below 50°C. Ablation induced a complete conduction block in 8/12 cases (4/4 for 10 W at 2 mL min-1, 1/4 for 10 W at 5 mL min-1, 3/4 for 15 W at 5 mL min-1). Blocks were characterized by a decrease in signal amplitude at the lesion site, along with changes in slow-wave propagation patterns, where slow waves terminated at and/or rotated around the edge of the lesion. Power-controlled, irrigated ablation can successfully modulate gastric slow-wave activity at a reduced catheter-tip temperature compared to temperature-controlled, non-irrigated ablation. Reducing the irrigation rate is more effective than increasing power for blocking slow-wave activity. These benefits suggest that irrigated ablation is a suitable option for further translation into a clinical intervention for gastric electrophysiology disorders.

Metabolic rate and saliva cortisol concentrations in socially housed adolescent guinea pigs

An individual’s energetic demands and hence metabolic rate can strongly change during adolescence, a phase characterized by profound morphological, physiological, and endocrine changes. Glucocorticoid hormones (e.g. cortisol) are released in response to hypothalamic–pituitary–adrenal–axis activity, modulate several metabolic processes, and can also be linked to increased metabolic rate. In domestic guinea pigs (Cavia aperea f. porcellus) housed in same-sex groups, cortisol concentrations increase during adolescence in males but remain stable in females, which was suggested to be related to different energetic demands by age. We therefore measured metabolic rate through oxygen (O2) consumption over 2.5 h in male and female guinea pigs housed in same-sex groups during adolescence at ages of 60, 120, and 180 days, which was paralleled by analyses of saliva cortisol concentrations before and after the measurement. The statistical analyses involved whole body metabolic rate (ml O2/h), body mass-corrected metabolic rate (ml O2/h/kg), and body mass-independent metabolic rate (ml O2/h statistically corrected for body mass). We found increasing cortisol concentrations with age in males only, but none of the three metabolic rate analyses revealed a sex difference by age. On the individual level, repeatability across ages was found in metabolic rate as well as in body mass and cortisol concentrations after the measurement, but not in “basal” cortisol concentrations. Our results suggest no sex-specific changes in metabolic rate and hence equal energetic demands in male and female guinea pigs during adolescence. Moreover, metabolic rate clearly represents a highly stable physiological trait already early in a guinea pig’s life irrespective of rather fluctuating cortisol concentrations.

Pulsed-field ablation: an alternative ablative method for gastric electrophysiological intervention.

Pulsed-field ablation (PFA) is an emerging ablative technology that has been used successfully to eliminate cardiac arrhythmias. As a nonthermal technique, it has significant benefits over traditional radiofrequency ablation with improved target tissue specificity and reduced risk of adverse events during cardiac applications. We investigated whether PFA is safe for use in the stomach and whether it could modulate gastric slow waves. Female weaner pigs were fasted overnight before anesthesia was induced using tiletamine hydrochloride (50 mg·mL-1) and zolazepam hydrochloride (50 mg·mL-1) and maintained with propofol (Diprivan 2%, 0.2-0.4 mg·kg-1·min-1). Pulsed-field ablation was performed on their gastric serosa in vivo. Adjacent point lesions (n = 2-4) were used to create a linear injury using bipolar pulsed-field ablation consisting of 40 pulses (10 Hz frequency, 0.1 ms pulse width, 1,000 V amplitude). High-resolution electrical mapping defined baseline and postablation gastric slow-wave patterns. A validated five-point scale was used to evaluate tissue damage in hematoxylin and eosin-stained images. Results indicated that PFA successfully induced complete conduction blocks in all cases, with lesions through the entire thickness of the gastric muscle layers. Consistent postablation slow-wave patterns emerged immediately following ablation and persisted over the study period. Pulsed-field ablation induces rapid conduction blocks as a tool to modulate slow-wave patterns, indicating it may be suitable as an alternative to radiofrequency ablation.NEW & NOTEWORTHY Results show that pulsed-field ablation can serve as a gastric slow-wave intervention by preventing slow-wave propagation across the lesion site. Stable conduction blocks were established immediately following energy delivery, faster than previous examples of radiofrequency gastric ablation. Pulsed-field ablation may be an alternative for gastric slow-wave intervention, and further functional and posthealing studies are now warranted.

Cryoneurolysis of the saphenous nerve in the pig: A proof-of-principle investigation

ObjectiveTo determine if in vivo cryoneurolysis inhibits ex vivo compound action potential (CAP) conduction in the porcine saphenous nerve and if this occurs rapidly enough to justify performing the technique before stifle surgery. Study designBlinded, controlled, randomized, preclinical study. AnimalsA group of eight healthy, 8 weeks old, intact, female pigs anesthetized for an unrelated terminal study. MethodsBoth saphenous nerves of each pig were exposed surgically, and 15 mm of a 20 gauge, closed-tip, commercial cryoneurolysis cannula were inserted cranial to each nerve within the neurovascular fascial sheath along its long axis. The cannula was only actuated on one limb, according to random allocation. Nerves were excised within 15 minutes of actuation and underwent testing in a nerve conduction chamber, where stimulus voltage was increased sequentially (from 0.1 to ≤ 1.9 V). An anesthesiologist blinded to treatment viewed recordings of time versus voltage for each nerve and answered ‘yes’ or ‘no’ when asked if an evoked CAP was observed. Fisher’s exact test evaluated the incidence of CAP conduction between groups (p < 0.05 considered significant). Nerves were submitted for hematoxylin and eosin staining for blinded histopathological examination. ResultsA CAP was conducted in 8/8 and 1/8 of the control and treated nerves, respectively (p = 0.001). Maximal responses in control nerves were 1.92 ± 0.19 mV (mean ± standard error). In the single treated nerve that conducted a CAP, the maximal CAP amplitude was 0.4 mV, lower than the lowest maximal CAP (1.19 mV) in the control nerves. All control nerves were histologically normal, and all treated nerves displayed mild perivascular and perineural inflammation (cuffs of lymphocytes, plasma cells and eosinophils, and edema). Conclusions and clinical relevanceThe rapid inhibition of CAP conduction warrants clinical investigation of saphenous cryoneurolysis for both intraoperative antinociception and postoperative analgesia in pigs undergoing experimental stifle surgery.

A Standardized Porcine Model for Partial-Thickness Wound Healing Studies: Design, Characterization, Model Validation, and Histological Insights.

Wound healing is a complex process that is still not fully understood despite extensive research. To address this, we aimed to design and characterize a standardized porcine model for the evaluation of wound healing, dressings, cell therapies, and pharmaceutical agents. Using a standardized approach, we examined the wound healing process in 1.2 mm-deep dermatome wounds at defined positions in 11 female pigs. Unlike previous studies that have only described/analyzed selected punch biopsies, we performed and described histological analyses along the complete wound length using quantitative morphometric methods. All animals remained fully healthy following surgery and showed no signs of infection. Our histopathological evaluation using a predetermined grading score and quantitative manual morphometry demonstrated the impact of different tissue sampling methods, sampling sites, and residual dermis thickness on wound healing. Our study presents a reproducible model for wound healing evaluation and demonstrates the usefulness of porcine models for assessing dermal and epidermal wound healing. The use of histological analyses over the complete wound length provides advantages over previous studies, leading to the possibility of a deeper understanding of the wound healing process. This model could potentially facilitate future research on novel wound dressings and local wound healing therapies.

Evaluation of lingual oscillometric blood pressure measurement in anaesthetized pigs

ObjectiveTo evaluate the agreement between measurements of invasive blood pressure (IBP) and oscillometric blood pressure from the tongue (OBPton) using a multiparameter monitor. Study designUnblinded, prospective, experimental study. AnimalsA total of 12 female Large White crossbreed pigs. MethodsPigs undergoing experimental procedures that required arterial cannula placement were recruited. A blood pressure cuff with the closest width to 40% of the circumference of the tongue was placed rostral to the lingual frenulum. Systolic, mean and diastolic IBP and OBPton were measured simultaneously at 5 minute intervals. Agreement between paired measurements was examined using Bland–Altman analysis. Mean bias, precision (standard deviation of mean bias), 95% limits of agreement, correlation coefficients and percentage of measurements within 10 and 20 mmHg of IBP were calculated. ResultsThe total numbers of paired measurements recorded were 124, 126 and 124 for systolic, mean and diastolic blood pressures, respectively. The mean bias, precision and 95% limits of agreement for systolic OBPton were 11.5, 11.5 (–11.1 to 34.2), for mean OBPton 5.6, 5.7 (–5.7 to 16.8) and for diastolic OBPton 7.6, 10.1 (–12.1 to 27.4) mmHg. Correlation coefficients were greater than 0.9 for mean OBPton only. More than 50% of measurements were within 10 mmHg of IBP and 80% of measurements were within 20 mmHg of IBP for mean and diastolic OBPton only. Conclusions and clinical relevanceThe tongue as a cuff site for oscillometric blood pressure measurement is a useful site for measuring mean arterial, but not systolic or diastolic blood pressure in anaesthetized Large White crossbreed pigs. This technique fulfils the American College of Veterinary Internal Medicine criteria for measuring mean arterial pressure but not systolic or diastolic arterial pressure.

Survival and Neurologic Outcomes From Pharmacologic Peptide Administration During Cardiopulmonary Resuscitation of Pulseless Electrical Activity.

Outcomes from cardiopulmonary resuscitation (CPR) following sudden cardiac arrest are suboptimal. Postresuscitation targeted temperature management has been shown to have benefit in subjects with sudden cardiac arrest due to ventricular fibrillation, but there are few data for outcomes from sudden cardiac arrest due to pulseless electrical activity. In addition, intra-CPR cooling is more effective than postresuscitation cooling. Physical cooling is associated with increased protein kinase B activity. Therefore, our group developed a novel peptide, TAT-PHLPP9c, which regulates protein kinase B. We hypothesized that when given during CPR, TAT-PHLPP9c would improve survival and neurologic outcomes following pulseless electrical activity arrest. In 24 female pigs, pulseless electrical activity was induced by inflating balloon catheters in the right coronary and left anterior descending arteries for ≈7 minutes. Advanced life support was initiated. In 12 control animals, epinephrine was given after 1 and 3 minutes. In 12 peptide-treated animals, 7.5 mg/kg TAT-PHLPP9c was also administered at 1 and 3 minutes of CPR. The balloons were removed after 2 minutes of support. Animals were recovered and neurologically scored 24 hours after return of spontaneous circulation. Return of spontaneous circulation was more common in the peptide group, but this difference was not significant (8/12 control versus 12/12 peptide; P=0.093), while fully intact neurologic survival was significantly more common in the peptide group (0/12 control versus 11/12 peptide; P<0.00001). TAT-PHLPP9c significantly increased myocardial nicotinamide adenine dinucleotide levels. TAT-PHLPP9c resulted in improved survival with full neurologic function after sudden cardiac arrest in a swine model of pulseless electrical activity, and the peptide shows potential as an intra-CPR pharmacologic agent.

Establishment of urinary catheter materials antibacterial efficacy evaluation platform in pigs

Urinary catheters are one of the common invasive medical catheters, mostly composed of high-polymer materials such as polyurethanes. During clinical use, the high friction between the catheter material surface and tissues can lead to tissue damage, patient discomfort, and pain during insertion or removal. Moreover, due to the hydrophobic nature of the polymer material surface, there is a risk of urinary tract infections (CTIs) caused by problems such as protein adsorption and bacterial infection upon insertion into the body. Prolonged indwelling time of urinary catheters in the body increases the probability of other complications, potentially leading to life-threatening consequences and imposing medical burdens. Therefore, the purpose of this study was focused on the insertion of the Escherichia coli (E. coli, 1 × 105 CFU/mL)-coated urinary catheter to implant into a female pig’s urethra for establishing the urinary catheter materials antibacterial efficacy evaluation platform in pigs. Results were shown that during the experimental period, the week 1 and week 2 average pig’ body temperature were 39.4 ± 0.6°C and 39.1 ± 0.2°C, respectively. The average pig’s body temperature was normal and there was no significant differences in body temperature at week 1 and week 2 urinary catheter implanted-experiment period. Moreover, the clinical observation of the pigs showed that their vitality, appetite, and excretion were all normal, and they survived until the end of the experiment without presenting any abnormal clinical symptoms. In addition, E. coli in urine culture respectively showed 0.95 ± 0.03 × 105 CFU/mL, 1.23 ± 0.03 × 105 CFU/mL, 1.43 ± 0.04 × 105 CFU/mL, 1.75 ± 0.08 × 105 CFU/mL, and 1.91 ± 0.09 × 105 CFU/mL on day 0, 3, 7, 10, and 14 of urinary catheter implantation. As time progressed after urinary catheter implantation, there was an increasing trend in E. coli counts. Staining with crystal violet for urinary catheter showed that the urinary catheter wall was positive for crystal violet staining. E. coli isolation and counts from biofilm on inside and outside of urinary catheter respectively showed 5.10 ± 0.10 × 105 CFU/mL and 7.50 ± 1.08 × 105 CFU/mL on day 14 of urinary catheter implantation. As time progressed after urinary catheter implantation, there was an increasing trend in E. coli counts. Finally, the pathological interpretation of the urinary tract indicates that in the tissue morphology of the bladder, there is observed a localized mild shedding of superficial and intermediate layer cells in the transitional epithelium of the ureteral stent group, with only basal cells remaining connected to its submucosa. There are no significant pathological changes observed in the tissue morphology of the urethra and kidneys. According to the results of this study, a urinary catheter materials antibacterial efficacy evaluation platform in pigs has successfully established, which can be provided for R&amp;D of urinary catheter antibacterial materials.