Animals ; Dentistry ; Swine ; Swine, Miniature

All endoureteromy procedures have in common the use of a ureteral stent as post-procedure However, the optimal stent size necessary to promote satisfactory healing is not known. Herein we compared healing of an endoureterotomy over a 7 Fr indwelling ureteral stent (IUS) with healing over a 14 Fr endopyelotomy stent( ES). A mid-ureteral stricture was created in each of 25 anesthetized, female minipigs using a retrograde electrified stone basket. Six weeks later, retrograde ureterograms(RU) revealed a stricture in 24 pigs ; ureteral incision was performed with a 24 Fr cutting balloon device. Twenty pigs were randomized to receive a 7 Fr IUS or a 14 Fr ES; 4 control pigs were performed to confirm proper stent position and the stents were removed. At 3 months. RU was repeated and the ureters were grossly examined and harvested for histological studies. Two pigs in each group had recurrent strictures. Despite a 50 years history of endoureterotomy, optimal stent size remains an endourologic unknown. Our study represents the first attempt at directly comparing stents of different size in an in vivo ureteral stricture model. There is no significant difference between 7 Fr and 14 Fr stents.
Constriction, Pathologic* ; Female ; Humans ; Stents* ; Swine ; Swine, Miniature ; Ureter*

BACKGROUNDThe aim of this research was to evaluate the feasibility and efficacy of absorbable bandage wrapping in the treatment of cases of severe liver trauma.

METHODSElectric firecrackers were detonated in 16 miniature swine to produce a severe blast liver injury. After fluid resuscitation, the animals were randomly divided into two groups (n = 8 each) and were either treated with absorbable bandage wrapping of the injured lobe of liver (Group B) or hepatic lobectomy (Group H). Time to hemostasis, blood loss during the treatment period, and other parameters were compared, including postoperative serum total bilirubin (TB), alanine aminotransferase (ALT), and aspartate aminotransferase (AST).

RESULTSBlood loss during the treatment period was significantly lower in Group B than that in Group H ((81.3 ± 26.0) ml vs. (130.8 ± 29.5) ml, P = 0.0031). Serum AST and ALT were transiently increased post-surgically. These transient increases were significantly higher in Group B. No difference in time to hemostasis was noted ((8.70 ± 2.27) minutes vs. (10.28 ± 1.93) minutes, P = 0.1559) in Groups B and H, respectively. Two pigs were humanely euthanized 28 days post-surgically and the wrapped liver lobes appeared atrophies. Microscopically, there was evidence of emerging and mature fibrous tissue.

CONCLUSIONAbsorbable bandage wrapping is both feasible and effective in the treatment of severe blast liver injury.

Animals ; Bandages ; Female ; Liver ; injuries ; surgery ; Male ; Swine ; Swine, Miniature

OBJECTIVETo evaluate the effects of a solitary megadose protocol of ionizing radiation (IR) to parotid gland on the structured and function changes of bilateral parotid glands in miniature pig.

METHODSFourteen minipigs were subjected to either 15 or 20 Gy to one parotid gland with a linear accelerator, while another four minipigs served as non-IR controls. Salivary flow rates and salivary chemistries were measured pre-IR, and 4 and 16 weeks post-IR. A quantitative assessment of gland weight and acinar area, and detailed serum chemistry and hematological analyses, were also performed.

RESULTSParotid gland weights were significantly decreased in the 15 and 20 Gy groups at 4 and 16 weeks post-IR. The acinar cell area in glands of both IR groups was significantly reduced. Parotid flow rates decreased by 60% with 15 Gy at 16 weeks post-IR. In the 20 Gy group, salivary flow rates were reduced by 80% at 16 weeks post-IR. Additionally, parotid flow rates significantly reduced in contralateral glands with 20 Gy at 16 weeks, while structure and weight did not changes in parotid glands.

CONCLUSIONStructural changes in salivary gland parenchyma occurred relatively early after IR, while the alterations in salivary output were relatively delayed. Further, reductions in salivary flow were not proportional to acinar cell area loss. There isn't a significant structured change of contralateral glands, but significant reduction of parotid flow rate at this time.

Animals ; Parotid Gland ; radiation effects ; Swine ; Swine, Miniature

OBJECTIVETo create a standard mini-swine model of chronic ischemic myocardium by endoscopy for the research of gene transfer and stem cell.

METHODSTwenty-three male China experimental minipigs were used, aged from 8 to 11 months with a mean of (9.3 +/- 1.8) months and weighed from 20 to 30 kg with a mean of (29.3 +/- 4.3) kg. The myocardial ischemia was established by gradual occlusion of the left circumflex coronary artery (LCX) with an Ameroid constrictor. The Ameroid constrictor was implanted around LCX by endoscopy. Selective coronary angiography, electrocardiogram and Echo-Doppler study were performed perioperatively to evaluate the degree of stenosis.

RESULTSChronic ischemic myocardial models were successfully generated in 20 of 23 swine by full-endoscopy. Ameroid constrictors were placed at the LCX accurately. Three swine died of anesthetic accident, cardiac arrhythmia at secondary coronary angiography, and pulmonary infection within 6 weeks after operation respectively. Operation time was 25 to 65 min with a mean of (46 +/- 9) min. The blood loss was 30 to 60 ml with a mean of (55 +/- 12) ml. Six weeks later, coronary angiography revealed the total occlusion and partial stenosis (> 85%) of the LCX occurred in 7 and 13 swine respectively. Cardiac systolic and diastolic dysfunction were found in all swine. The ejection fraction value was (65.0 +/- 6.3)% before operation and (41.0 +/- 9.3)% after operation (P = 0.008). The fractional shortening value was (36.2 +/- 4.3)% before operation and (34.2 +/- 2.3)% after operation (P = 0.027).

CONCLUSIONThe endoscopic surgery is a less invasive way to create a standard mini-swine model of chronic ischemic myocardium with effective results.

Animals ; Disease Models, Animal ; Feasibility Studies ; Male ; Myocardial Ischemia ; Swine ; Swine, Miniature ; Thoracoscopes

OBJECTIVETo establish a neonatal Tibet minipig model of hypoxic-ischemic encephalopathy and evaluate the magnetic resonance imaging (MRI) manifestations and pathological findings.

METHODSSix neonatal (1-3 days old) Tibet minipigs were randomized into model group (n=4) and control group (n=2). In model group, hypoxic-ischemic encephalopathy was induced by surgical ligation of the bilateral carotid artery followedimmediately by hypoxic exposure in a hypoxia chamber for 1 h. ESWAN was performed at 2 h, 24 h, 3 days and 5 days after induction of HIE or at 2 h after sham surgery in the control animals to evaluate the brain damage. Conventional MRI scans (T2FLAIR, T2WI, and DWI) were also performed at 24 h after the modeling.

RESULTSIn the neostriatum, values of T(2)*-weighted MRI increased and reached the peak level at 3 days post-injury (P<0.05). Subcortical white matter T(2)* values reached the peak level at 24 h (P<0.05). Neostriatum R(2)* values were at the lowest level at 3 days (P<0.05). Magnitude values were significantly increased after the model establishment (P<0.05). DWI showed multiple mild focal high signals in the bifrontal subcortical white matter and bilateral neostriatum; T2FLAIR showed slightly increased signal; T2WI showed no obvious abnormalities. SWI showed dilated medulla veins adjacent to the bilateral lateral ventricles and basal ganglia. In the early stage of HIE, brain pathologies were characterized mainly by edema and venous congestion with occasional focal necrosis and hemosiderin deposition.

CONCLUSIONESWAN sequence is capable of detecting bleeding and brain edema, and T(2)*, R(2)*, and magnitude values can be used to estimate the changes of brain damage following HIE.

Animals ; Disease Models, Animal ; Hypoxia-Ischemia, Brain ; diagnosis ; pathology ; Magnetic Resonance Imaging ; Swine ; Swine, Miniature ; Tibet

BACKGROUNDAutologous transplantation of the submandibular gland (SMG) into the temporal fossa with microvascular anastomosis has been successfully applied in severe xerophthalmia patients as a permanent tear substitute. However, severe xerophthalmia can be accompanied by salivary gland dysfunction, making such autotransplantation unsuitable. Therefore, SMG allotransplantation might be a solution. The aim of this study was to assess the technical feasibility of submandibular gland allotransplantation.

METHODSTwelve miniature swine were randomized to serve as donors or recipients. One SMG was transplanted between a donor and a recipient. The donor SMG was revascularized by microvascular anastomosis of its vascular pedicle to the recipient lingual artery and external jugular vein. The secretory duct was implanted into the vestibule of the mouth through a subcutaneous tunnel. No immunosuppressive agent was administered. The results were assessed by visual inspection of the secretion, and histopathological examination of the transplanted SMG.

RESULTSTechnically, all surgical procedures were successful. Clear secretion flowed out of the duct as soon as blood supply of the transplanted submandibular gland was reestablished. The secretion of the gland lasted for 5 days. As expected, an acute rejection reaction occurred after surgery because no immunosuppressive agents were used. Secretion from the transplanted SMG ceased within 5 days.

CONCLUSIONSA model of SMG allotransplantation can be established in miniature swine. The technique of submandibular gland allotransplantation is feasible.

Animals ; Microscopy, Electron ; Models, Animal ; Submandibular Gland ; pathology ; transplantation ; ultrastructure ; Swine ; Swine, Miniature ; Transplantation, Homologous

OBJECTIVETo establish a animal model of biliary leakage in pigs with laparoscopy.

METHODSEight healthy Bama minipigs were subject to laparoscopic surgery under general anesthesia.The cystic duct was resected at 0.5-1.0 cm from the root and the stump was left open with the gallbladder removed. Blood routine and hepatic functions of the pigs were tested before and 24 h after the surgery, and endoscopic retrograde cholangiography (ERC) was performed 24 h after the surgery. At 48 h after the surgery, the pigs were sacrificed for observation of the stump of the cystic duct.

RESULTSThe gallbladder, cystic duct, cystic artery, and the anatomical relations between the gallbladder and liver and between the cystic duct and common bile duct were fully exposed under laparoscopy. White blood cells, neutrophils and direct bilirubin increased significantly after the operation (P<0.05). The cystic ducts were resected at 0.5-1 cm away from the roots of the cystic ducts in 7 pigs and at 2 cm in 1 pig.

CONCLUSIONLaparoscopy is safe and feasible for establishing the porcine model of biliary leakage.

Animals ; Biliary Fistula ; Cystic Duct ; surgery ; Disease Models, Animal ; Female ; Laparoscopy ; Male ; Swine ; Swine, Miniature

OBJECTIVETo demonstrate the ablation of segmental glissonian pedicle by ultrasound-guided radiofrequency in precision liver resection in porcine model.

METHODSThe study was carried out on 6 Bama miniature pigs. Coagulative desiccation of the vessels feeding the segment to be resected was induced by introduction of a "cooled-tip" radiofrequency electrode under intraoperative ultrasound guidance at the level of the vessels. Then, an area of marked discoloration on the surface of the liver became obvious. Liver parenchymal transection followed without any form of hepatic inflow occlusion. Three segments (segment 3, 5, and 6) were resected on each pig. The criteria studied the local and general tolerance, the change of blood flow parameters of each segmental arterial and portal branches, and the microscopic appearance of the segmental arterial, portal and biliary tract branches. Using t test as the statistical methods.

RESULTSPostoperative mortality and morbidity were 0 and all serum parameters had normalized by 14 days. Demarcation area was obtained in 15 segments. The flow rate of the resected segmental portal branches was 0 cm/s after radiofrequency and the value of the arterial branches was (28 ± 18) cm/s which was significantly lower than pre-radiofrequency, which were (10.2 ± 3.0) cm/s and (60 ± 17) cm/s (t = 14.439, 5.502; P = 0.000). There was no significant difference in the flow rate of the remnant segmental arterial and portal branches among pre-radiofrequency, post-radiofrequency and 14 days after operation. On microscopic observation, the mean ablated length of segmental portal, arterial and biliary tract branches were (1.6 ± 0.4) cm, (1.2 ± 0.4) cm, and (1.7 ± 0.3) cm respectively.

CONCLUSIONSThe ablation of the segmental glissonian pedicle by ultrasound-guided radiofrequency is quick, safe and effective. The probe needs to be away from vessels feeding segments 1.5 cm at least to avoid thermal injuries.

Animals ; Catheter Ablation ; methods ; Female ; Hepatectomy ; methods ; Male ; Swine ; Swine, Miniature ; Ultrasonography

OBJECTIVETo investigate the relationship between the survival rate of expanded flap and expansion volume.

METHODSThe minipigs were used and divided into 5 groups according to different expansion volume of the tissue expanders: injection to full content, 50% over content, 100% over content, 0% content and normal control. In each animal, 4 expanders (100 ml) were designed to be implanted at the bilateral side of back. Normal skin control was also designed at the back. The skin histologic change and flap survival rate were detected and analyzed when the expansion volume changed.

RESULTSThe flap survival rate increased along with the increase of expansion volume. While the survival rate decreased when the expansion volume was exceeded to 100% over content.

CONCLUSIONSIn soft tissue and skin expansion, the flap survival rate and the flap size increased as the expansion is over the standard volume, while over-expansion to 100% over content may cause decreased survival rate of expanded flap.

Animals ; Back ; Graft Survival ; Surgical Flaps ; physiology ; Swine ; Swine, Miniature ; Tissue Expansion ; Tissue Expansion Devices