Animals ; Dentistry ; 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

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 investigate the change of morphology, biomechanics and histology after osteotomy of mandibular outer cortex.

METHODSThe mandibular outer cortex that involves angle and part of body was removed at one side in 8 minitype pigs aged 8-12 months. 2 pigs were selected randomly for histologic examination 12 weeks after operation. The other 6 animals were killed 24 weeks after operation. The thickness of new-formed mandibular outer cortex was measured and compared with that of operated side. Biomechanical test was performed in bilateral angles. Histological observation was made in the operated side.

RESULTSThe thickness of outer cortex was (2.1 +/- 0.3) mm and (2.5 +/- 0.4) mm in the operated side and opposite side, respectively, showing a significant difference between them (P < 0.01). The maximum load was (401.76 +/- 204.91) N and (585.42 +/- 413.07) N in the operated side and opposite side, respectively (P > 0.05). The Rigidity was (2172.19 +/- 1174.73) N/mm and (2363.90 +/- 1547.48) N/mm (P > 0.05). There was no statistical difference in biomechanics between the two sides. The histologic study showed histologically complete regeneration of outer cortex 24 weeks after mandibular outer cortex osteotomy.

CONCLUSIONSAfter resection of mandibular outer cortex, the histologic restoration is complete, but the new-formed outer cortex is thinner with local depression. Bone tubercle can be seen at the angle after bone regeneration. There is no obvious change in biomechanics after outer cortex osteotomy.

Animals ; Biomechanical Phenomena ; Female ; Male ; Mandible ; surgery ; Osteotomy ; methods ; Swine ; Swine, Miniature

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.

Animals ; Dobutamine ; Magnetic Resonance Imaging, Cine ; methods ; Male ; Swine ; Swine, Miniature ; Ventricular Function, Left

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

OBJECTIVETo study scutellarin starch microspheres' permeability through nasal mucosa of different animals in vitro.

METHODThe Franz diffusion cell method was used to experiment the permeability test (n = 4), taking fresh nasal mucosa of dog, swine and domestica in vitro as permeation barrier separately, with scutellarin starch microspheres (scutellarin 0.25 mg) above them, and blank pH 6.8 PBS as absorption liquid to detemine the scutellarin by HPLC.

RESULTThe permeability coefficient of scutellarin starch microspheres through nasal mucosa of dog, swine and domestica in vitro were (5.295 +/- 0.637) x 10(-3) (4.065 +/- 1.140) x 10(-3), (1.855 +/- 0.150) x 10(-3) cm x mL(-1) separately. The permeability coefficient order of scutellarin starch microspheres through nasal mucosa of different animals in vitro is dog > swine > domestica, and there are significant differences between the permeability coefficient of scutellarin starch microspheres through nasal mucosa of dog, swine in vitro, and that through nasal mucosa of swine and domestica in vitro.

CONCLUSIONDrugs in scutellarin starch microspheres could permeate through the above-mentioned nasal mucosa in vitro. There might be different permeability coefficient among different species.

Animals ; Apigenin ; pharmacokinetics ; Dogs ; Glucuronates ; pharmacokinetics ; Microspheres ; Nasal Mucosa ; metabolism ; Permeability ; Starch ; pharmacokinetics ; 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 study the safety of the novel high nitrogen nickel-free austenitic stainless steel bare metal stents (BMS) in a recognized porcine coronary model and to select a better grid structure of it.

METHODSThree types of stents were randomly implanted in different coronary arteries of the same pig: 316 L stainless steel BMS (316 L-BMS) (n=12), novel high nitrogen nickel-free stents Grid A (NF-A-BMS) (n=12) and novel high nitrogen nickel-free stents Grid B (NF-B-BMS) (n=12). In total, eighteen animals underwent successful random placement of 36 oversized stents in the coronary arteries. Coronary angiography was performed after 36 d of stents implantation. Nine animals were respectively sacrificed after 14 d and 36 d for histomorphologic analysis.

RESULTSQuantitative coronary angiography (QCA) showed similar luminal loss (LL) in the three groups: (0.21 ± 0.17) mm for 316 L-BMS, (0.16 ± 0.12) mm for NF-A-BMS, (0.24 ± 0.15) mm for NF-B-BMS (P>0.05). Histomorphomeric analysis after 15 d and 36 d revealed that there was also no significant difference among the three groups in neointimal area (NA) with similar injury scores respectively. High magnification histomorphologic examination showed similar inflammation scores in the three groups, but NF-A-BMS group had poorer endothelialization scores compared with NF-B-BMS group, 2.00 ± 0.63 vs. 2.83 ± 0.41 (P=0.015) at 15 d, which also could be proved by the scanning electron microscope. However, the difference could not been observed at 36 d.

CONCLUSIONThe novel NF-BMS showed similar safety as 316 L-BMS during the short-term study. NF-B-BMS had better endothelialization than NF-A-BMS and this may owe to the specific strut units.

Animals ; Coronary Vessels ; Nickel ; Nitrogen ; Random Allocation ; Stainless Steel ; chemistry ; Stents ; Swine ; Swine, Miniature