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

The production of miniature animals has been suggested for use in organ transplantation. At present, many of the studies about application of animal organs to human have been focused on pigs because of the number of advantages involved and due to their similarities with human. However, a physiological analysis of the organs to be transplanted has not yet been carried out. Therefore, this study analyzed whether or not there were physiological and morphological differences in the hearts of conventionallyreared pigs and micropigs. In this study, the morphological and physiological functions of the heart were examined using radiographic and echocardiographic equipment. In the lateral radiographic view, the heart of the micropig has a larger cardiac long axis : short axis ratio than does the conventional pig, but the difference in the vertebral heart score was not significant. In addition, there were no morphological differences on the X-ray fluoroscopic view. There were no differences in echocardiographic values, except for several values in the left ventricle traces. Overall, it is expected that the values measured in this study will contribute to understanding of the physiological characteristics of micropigs.
Animals ; Echocardiography/veterinary ; Fluoroscopy/veterinary ; Heart/*physiology/*radiography ; Stroke Volume/physiology ; 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 investigate the feasibility of using intravascular loopless monopole antenna (ILMA) to image atherosclerosis plaque in a porcine model with 3.0T magnetic resonance imaging (MRI).

METHODSAtherosclerosis model was established by feeding high fat diet combined with balloon catheter injury to the endothelium in 6 pigs. After 3 months, animals underwent MRI and ILMA examination. The ILMA was invasively inserted to the distal part of abdominal vein and bilateral common iliac veins. MR sequences including T1 weighted imaging (T1WI), T2WI were obtained. MR image data were transferred to post-processing station. Luminal border and external elastic membrane of the vessel were reconstructed based on the MR images. After co-register these images, vessel area, lumen area, vessel wall area and plaque burden in the same lesions imaged by different modality were calculated and compared. Finally, all animals were scarified and hematoxylin eosin (HE) staining was performed in the targeted vessels. Diagnostic accuracy of MR in delineating vessel wall and detecting plaque were analyzed and calculated by comparing with pathological results.

RESULTSThe atherosclerotic model was successfully established in all 6 pigs. Good agreement of delineating vessel area, lumen area vessel, wall area and plaque burden were found between MRI and pathology with r value of 0.98, 0.95, and 0.96, respectively (P < 0.001). Compared with pathological findings, the plaque component in corresponding area imaged by MR was as follows: sensitivity and specificity of detecting lipid plaque were 77% and 69%, kappa value was 0.75 ± 0.19 (P < 0.01); sensitivity and specificity on detecting fibrotic plaque were 78% and 73%, Κ value was 0.78 ± 0.18 (P < 0.01). The sensitivity and specificity of detecting calcified plaque were 100%. ILMA results showed that the average lumen area was 49.72 mm(2), average vessel area was 124.08 mm(2), and the average vessel wall area was 74.37 mm(2), ILMA slightly overestimated these indexes as compared with pathological results.

CONCLUSIONThe results showed that ILMA could be used to image deepened artery and atherosclerotic plaque. Detected plaque size, vessel area, lumen area vessel, wall area, and plaque burden were comparable to pathological findings. It may thus provide an alternative method for detecting atherosclerotic plaque in future research work.

Animals ; Disease Models, Animal ; Magnetic Resonance Angiography ; methods ; Plaque, Atherosclerotic ; diagnosis ; 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

BACKGROUNDMiniature pig (minipig) is increasingly used as a large animal model for a variety of biomedical studies. Little information is available in the literature on anatomy, histology and sialograghy of the submandibular gland of the minipig. The purpose of this study was to characterize the morphology of a miniature pig's (minipig) submandibular gland as a large animal model for further biomedical studies.

METHODSFive minipigs were subjected to sialographic, anatomic, histologic, histochemical and ultrastructural evaluations for submandibular glands.

RESULTSSialograms showed a long, horizontal main excretory duct and a pear-shaped gland located inferoposterior to the angle of the mandible. The submandibular glands lied superficial to the suprahyoid, and infrahyoid muscle groups, and were covered by the inferior portion of the parotid gland. The submandibular glands were characterized by a mixed parenchyma of mucous and serous secretory acini. Alcian blue (AB) staining and periodic acid-Schiff (PAS) reactions demonstrated that minipig submandibular glands synthesized and secreted acid mucous substances by serous cells and polysaccharide, and neutral mucous substances, by mucous cells.

CONCLUSIONThe submandibular gland of the minipig is considered a useful large salivary gland animal model for biomedical studies.

Animals ; Female ; Histocytochemistry ; Submandibular Gland ; chemistry ; cytology ; physiology ; ultrastructure ; Swine ; Swine, Miniature ; anatomy & histology

Animals ; Cryopreservation ; Liver ; Liver Transplantation ; Swine ; Swine, Miniature ; Time Factors ; Warm Ischemia