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*

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.

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.

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 assess a minipig model of acute myocardial infarction (AMI) established by percutaneous balloon occlusion using delayed-enhanced magnetic resonance imaging (DE-MRI).

METHODSA minipig model of AMI was established by placement of a 2.0 mm×15.0 mm percutaneous transluminal coronary angioplasty balloon in the middle left anterior descending artery (LAD) through a percutaneous femoral puncture in the right inguinal region. The left anterior descending coronary artery (LAD) was occluded for 90 min, followed by assessment of the infarct size and cardiac function with DE-MRI, and the results were confirmed by pathological examination.

RESULTSDE-MRI showed a mean infarcts size of 10.2∓2.9 cm3 in the minipig models. Compared to the control group, the minipigs with AMI had significantly increased end-diastolic and end-systolic volumes (P<0.05) with a decreased stroke volume, ejection fraction and cardiac output (P<0.001). These DE-MRI values were matched with the microsphere values obtained from short-axis slices in pathological examination.

CONCLUSIONWe have established a feasible approach for evaluating minipig models of AMI as a platform for assessing the therapeutic effect of stem cell transplantation for AMI.

BACKGROUNDPorcine liver performing efficient physiological functions in the human body is prerequisite for successful liver xenotransplantation. However, the protein differences between pig and human remain largely unexplored. Therefore, we investigated the liver expression profile of a highly inbred minipig line.

METHODSA cDNA library was constructed from liver tissue of an inbred Banna minipig. Two hundred randomly selected clones were sequenced then analysed by BLAST programme.

RESULTSAlignments of the sequences showed 44% encoded previously known porcine genes. Among the 56% unknown genes, sequences of 72 clones had high similarities with known genes of other species and the similarities to human were mostly above 0.80. The other 40 clones showing no similarity to genes in National Centre for Biotechnology Information are newly discovered, expressed sequence tags specific to liver of inbred Banna minipig. Twenty-two of the 200 clones had full length encoding regions, 38 complete 5' terminal sequences and 140 complete 3' terminal sequences.

CONCLUSIONThese newly discovered expression sequences may be an important resource for research involving physiological characteristics and medical usage of inbred pigs and contribute to matching studies in xenotransplantation.

To study the effect of continuous positive airway pressure (CPAP) on sleep physiology of mini pigs with obstructive sleep apnea syndrome (OSAS) induced by altitude hypoxia, 12 adult male mini pigs were randomly assigned into 2 groups, named A and B. The mini pigs in group A were treated with altitude hypoxia 6 h per day for 22 days, and then with CPAP 6 h per day for 30 days. For comparison, the mini pigs in group B were treated with altitude hypoxia only. The test of inspiration pressure of pharyngeal portion and the monitoring of sleeping were performed after the treatments of altitude hypoxia and CPAP. The sleeping monitor recorded the movements of chest and abdomen, respiratory airflow, heart rate, and pulse oxygen saturation (SpO2). The Apnea /Hypopnea Index (AHI), Apnea Index (AI), Hypopnea Index (HI), average SpO2 were all derived from the data of sleeping monitoring. In group A, the AHI and AI decreased after CPAP treatment; in the same time, SpO2 increased; these changes were significant (P < 0.05). The HI showed no significant change after CPAP treatment. The AHI, AI and HI of group A after CPAP treatment were significantly lower than those of group B after altitude hypoxia treatment only, and the SpO2 of group A was higher than that of group B. The pharyngeal inspiration pressure of group A was significantly decreased after CPAP treatment and was significantly lower than that of group B. All in all, the findings suggested that CPAP treatment could normalize the physiological indices of sleeping.
Animals ; Continuous Positive Airway Pressure ; Male ; Random Allocation ; Sleep Apnea, Obstructive ; physiopathology ; therapy ; Swine ; Swine, Miniature

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

OBJECTIVETo evaluate the diagnostic value of dobutamine stress magnetic resonance imaging (MRI) for myocardial viability.

METHODSTen male miniswines underwent left ventriculography and coronary angiography, followed by stenosis of the left circumflex coronary artery (LCX) using ameroid constrictor. More than one month later, left ventriculography and coronary angiography were performed again, followed by cine-MRI at rest and during stress with incremental dose of dobutamine 5 - 20 micro g.kg(-1).min(-1). Traditional and/or breath-hold cine-MRI were used to evaluate regional left ventricular wall motion, corresponding to basal, midventricular and apical short-axis tomograms. Regional wall motion score index (WMSI) was calculated. The miniswines were finally sacrificed for pathological examination. Triphenyl tetrazolium chloride (TTC) delineated myocardial infarction. Microscopy was used to identify myocardial cellular changes.

RESULTSOne pig died, one pig suffered from aneurysm and another showed no negative findings. The other seven pigs were found with hypokinetic (n = 4) or akinetic (n = 3) myocardial regions related to stenosed LCX. Their mean WMSI at rest for the lateral and posteroinferior walls (ischemic regions) of the left ventricle was 2.27 +/- 0.32, as compared with 1.00 +/- 0.00 (P < 0.01) for the corresponding nonischemic anteroseptal regions. Further, the mean WMSI for the ischemic regions was 2.27 +/- 0.32 at rest compared with 1.40 +/- 0.39 (P < 0.01) at the dose of dobutamine 5 micro g.kg(-1).min(-1). However, the mean WMSI at the doses of dobutamine 10 and 20 micro g.kg(-1). min(-1) were 1.70 +/- 0.76 and 1.75 +/- 0.83, respectively, with no significant difference as compared with the mean WSCI at rest (P > 0.05). The pathologic examination showed viable myocardium at the ischemic regions.

CONCLUSIONLow-dose dobutamine (5 micro g.kg(-1).min(-1)) recovers hypokinetic or akinetic myocardial regions, and dobutamine stress MRI can be used to detect myocardial viability.