OBJECTIVETo study the influences on mandibular development after removing the outer cortex of mandibular body in childhood minitype pig.

METHODSSix childhood minitype pigs were selected as the experimental animals. The outer cortex of mandibular body measured as 3.0 cm x 1.5 cm was removed in one side, and the other side remained intact as the control. The changes of mandibular modality and occlusion relationship as well as the histological and biomechanical changes were studied 24 weeks after operation.

RESULTSThere was no obvious difference compared with the control side in the height of the mandibular ramus and the length of the mandibular body, However, lateral deviation occlusion was found in some animals. The body thickness was thinner than that of the control side, there were no obvious biomechanical and histological differences between the two sides.

CONCLUSIONSThere was less influence on the growth of mandibular bone after removing one side of the outer cortex of the mandibular body in childhood minitype pig. But further study should be done for the cause of the lateral deviation of the mandible in part of the animals.

Animals ; Female ; Male ; Mandible ; growth & development ; surgery ; Mandibular Condyle ; surgery ; Osteotomy ; adverse effects ; Swine ; Swine, Miniature

Computed tomography (CT) exams were conducted to determine the distribution of abdominal fat identified based on the CT number measured in Hounsfield Units (HU) and to measure the volume of the abdominal visceral and subcutaneous fat in minipigs. The relationship between the CT-based fat volumes of several vertebral levels and the entire abdomen and anthropometric data including the sagittal abdominal diameter and waist circumference were evaluated. Moreover, the total fat volumes at the T11, T13, L3, and L5 levels were compared with the total fat volume of the entire abdomen to define the landmark of abdominal fat distribution. Using a single-detector CT, six 6-month-old male minipigs were scanned under general anesthesia. Three radiologists then assessed the HU value of visceral and subcutaneous abdominal fat by drawing the region of interest manually at the T11, T13, L1, L3, and L5 levels. The CT number and abdominal fat determined in this way by the three radiologists was found to be correlated (intra-class coefficient = 0.9). The overall HU ranges for the visceral and subcutaneous fat depots were -147.47 to -83.46 and -131.62 to -90.97, respectively. The total fat volume of the entire abdomen was highly correlated with the volume of abdominal fat at the T13 level (r = 0.97, p < 0.0001). These findings demonstrate that the volume of abdominal adipose tissue measured at the T13 level using CT is a strong and reliable predictor of total abdominal adipose volume.
Animals ; *Body Composition ; Male ; Subcutaneous Fat, Abdominal/*radiography ; Swine ; Swine, Miniature/growth & development/*physiology ; Tomography, X-Ray Computed/*veterinary

Animals ; Animals, Newborn ; Hepatocyte Growth Factor ; chemistry ; physiology ; Liver ; chemistry ; Molecular Weight ; Swine ; Swine, Miniature ; Tissue Extracts ; chemistry

To determine the characteristics of magnetic resonance (MR) signals of normal growing cartilage and identify the difference in transverse relaxation times between physeal and epiphyseal cartilage in vivo. 24 distal femora of 12 two-week-old piglets were imaged on a 1.5 Tesla GE MR scanner. Comparison was made between signal intensity on MR images and the structure shown in corresponding histologic sections. T2 values were measured in eight piglets by means of multiecho spin-echo sequences. Our results showed that MR imaging delineated five regions between the secondary ossification center and the metaphysis, which histologically correspond to the zone of provisional calcification of the secondary ossification center, physis of the secondary ossification center, epiphyseal cartilage, physis and zone of provisional calcification. The T2 value in the physeal cartilage was much larger than that in the epiphyseal cartilage (P<0.05). It is concluded that MRI findings could differentiate the different regions of growing cartilage. T2 is longer in physeal than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycans.
Animals, Newborn ; Femur/anatomy & histology ; Femur/growth & development ; Femur/metabolism ; Growth Plate/*anatomy & histology ; Growth Plate/*growth & development ; Growth Plate/metabolism ; *Magnetic Resonance Imaging ; Osteogenesis/physiology ; Swine

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.
Epiphyses/*anatomy & histology ; Femur/anatomy & histology ; Femur/*growth & development ; Gadolinium/*diagnostic use ; Growth Plate/*anatomy & histology ; Growth Plate/blood supply ; Growth Plate/growth & development ; Image Enhancement ; Magnetic Resonance Imaging ; Swine ; Swine, Miniature

Somatic cell nucleus transfer (SCNT) has been considered the most effective method for conserving endangered animals and expanding the quantity of adult animal models. Bama miniature pigs are genetically stable and share similar biological features to humans. These pigs have been used to establish animal models for human diseases, and for many other applications. However, there is a paucity of studies on the effect of ear fibroblasts derived from different age of adult Bama miniature pigs on nucleus transfer (NT). The present study examined the NT efficiency of ear fibroblasts from fetal, newborn, 1-, 2-, 4-, 6-, 12-month-old miniature pigs by using trypan blue staining, flow cytometry and NT technique, etc., and the cell biological function and SCNT efficiency were compared between groups. The results showed that ear fibroblasts grew well after passage in each group. Spindle-shaped cells initially predominated, and gradually declined with increase of culture time and replaced by polygonal cells. Irregular cell growth occurred in the 2-month-old group and the elder groups. The growth curves of the ear fibroblasts were "S-shaped" in different age groups. The cell proliferation of postnatal ear fibroblasts, especially those from 2-, 4-, 6-, 12-month-old miniature pigs was significantly different from that of fetus ear fibroblasts (P<0.05 or P<0.01). Two-month- and 4-month-old ear fibroblasts had a significantly higher proportion of G1 stage cells (85% to 91%) than those at 6 and 12 months (66% to 74%, P<0.01). The blastocyst rate of reconstructed embryos originating from newborn, 1-, 2-, 4-month-old donor pigs was 6.06% to 7.69% with no significant difference from that in fetus fibroblast group (8.06%). It was concluded that <4-month-old adult Bama miniature pigs represent a better donor cell resource than elder pigs.
Animals ; Blastocyst ; physiology ; Cell Proliferation ; Cells, Cultured ; Ear ; embryology ; growth & development ; Fibroblasts ; cytology ; physiology ; transplantation ; Nuclear Transfer Techniques ; Swine ; Swine, Miniature ; anatomy & histology ; embryology ; growth & development

BACKGROUND: Relaxin is a transforming growth factor β1 antagonist. To determine the effects of relaxin on scar reduction, we investigated the scar remodeling process by injecting relaxin-expressing adenoviruses using a pig scar model. METHODS: Scars with full thickness were generated on the backs of Yorkshire pigs. Scars were divided into two groups (relaxin [RLX] and Control). Adenoviruses were injected into the RLX (expressing relaxin) and Control (not expressing relaxin) groups. Changes in the surface areas, color index and pliability of scars were compared. RESULTS: Fifty days after treatment, the surface areas of scars decreased, the color of scars was normalized, and the pliability of scars increased in RLX group. CONCLUSION: Relaxin-expressing adenoviruses improved the surface area, color, and pliability of scars. The mechanism of therapeutic effects on scar formation should be further investigated.
Adenoviridae* ; Cicatrix* ; Genetic Therapy ; Pliability ; Relaxin* ; Swine ; Therapeutic Uses ; Transforming Growth Factors

A corticocancellous core was removed from both femurs and tibias in 5 skeletally immature pigs. The cavity was treated with 5%, 25% phenol cautery, cryosurgery, and normal saline irrigation (control). The animals were sacrified after 7days. The extent of the bone necrosis was assessed by gross examination, simple radiography, MRI evaluation and histological examination with tissue mapping. After cryosurgery, the extent of necrosis was most profound in the depth of 2.0-9.0mm beyond the cavity wall. The effect of 25%-phenol was next to cryosurgery, with a depth of 1.0-3.0mm of necrosis. 5%-phenol made necrosis with the depth of 1.0-2.5mm. Very mild degree of necrosis with the width of 0.5-1.0mm was found along the cavity wall even in control group. On MRI, signal change was well visualized on T2 weighted coronal section and it was quite coincided with the extent of bone necrosis proved by histological tissue mapping to all cases. When the epiphyseal plate was open or very close to the cavity, curettage itself, 5%- and 25%-phenol cautery and cryosurgery all produced mild ischemic necrosis along the provisional calcification zone of physeal plate. These findings suggest that cryosurgery made more profound necrosis beyond cavity than phenol cautery and MRI is very sensitive and specific to find osteonecrosis along the cavity wall after phenol cautery or cryosurgery. When epiphyseal plate is open or very close to the cavity, phenol cautery, or cryosurgery, or even curettage itself could produce an ischemic necrosis to the physeal plate itself.
Animals ; Cautery* ; Cryosurgery* ; Curettage ; Femur* ; Growth Plate ; Magnetic Resonance Imaging ; Necrosis* ; Osteonecrosis ; Phenol* ; Radiography ; Swine ; Tibia*

OBJECTIVEVectors commonly used for therapeutic angiogenesis such as adenovirus and plasmid had their own limitations. Adenovirus-associated virus (AAV) is a relatively new but probably more ideal vector as it is safe and efficient. We will study the efficiency of recombinant AAV-2 mediated vascular endothelial growth factor165 gene transfer in inducing angiogenesis and arteriogenesis, in improving blood flow and myocardium function in a porcine chronic myocardial ischemic model.

METHODSChinese experimental minipigs underwent placement of a left circumflex artery aneroid constrictor. Five weeks later, electrocardiogram, coronary angiography and magnetic resonance imaging were performed to confirm occlusion of LCX or ischemia of myocardium in LCX territory. Coronary blood flow, myocardium perfusion and left ventricular wall function were also evaluated. Then the animals were randomized to treatment with rAAV2-VEGF(165) (1 x 10(12) virus genome) or administration of PBS, both by direct myocardial injection. Three and six months after therapy, the animals were evaluated with regard to expression of VEGF(165) Capillary density and arteriole density of the ischemic myocardium, coronary angiography, myocardial perfusion and left ventricular function were also assessed six months after therapy.

RESULTSFive weeks after aneroid occluder implantation, all the animals demonstrated complete or nearly complete occlusion of LCX and perfusion deficiency in LCX territory. Three months after therapy, expression of VEGF(165) mRNA and protein were higher in the VEGF than control group. The difference between the two groups diminished after six months. There was significant increase in capillary density (1404.06 +/- 250.48/mm(2) vs 976.88 +/- 344.79/mm(2), P < 0.05) and arteriole density (167.81 +/- 36.29/mm(2) vs 116.56 +/- 34.48/mm(2), P < 0.05) in VEGF group compared with control. Comparison of myocardial perfusion demonstrated marked differences between the two groups with significant improvement in animals treated with rAAV2-VEGF(165). No significant improvement in left ventricular function was seen in either the VEGF or control group.

CONCLUSIONSTransmyocardial delivery of rAAV2-VEGF(165) resulted in VEGF gene expression for at least three months and stimulated angiogenesis and arteriogenesis in porcine model of chronic myocardial ischemia. Myocardial perfusion was also improved after VEGF gene delivery.

Adenoviridae ; genetics ; Animals ; Disease Models, Animal ; Gene Transfer Techniques ; Genetic Therapy ; Genetic Vectors ; Male ; Myocardial Ischemia ; therapy ; Swine ; Swine, Miniature ; Vascular Endothelial Growth Factor A ; genetics ; therapeutic use

OBJECTIVESTo determine the efficacy of combined use of transmyocardial stent with gene therapy to treat acute myocardial infarction in porcine model.

METHODS24 Chinese mini swines have been divided into 4 groups randomly: group myocardial infarction (group MI n(1) = 6), group transmyocardial stent (group ST n(2) = 6), group vascular endothelial growth factor (group VEGF n(3) = 6), group transmyocardial stent and VEGF (group ST + VEGF n(4) = 6). In group MI, acute myocardial infarction animal model has been established by the ligation of the left descending coronary artery. In group ST, after the establishment of the model, 3 transmyocardial stents were implanted. In group VEGF, an expression plasmid containing the gene-encoding VEGF(165) (300 microg) was administered directly in the myocardium at 6 sites. In group ST + VEGF, both transmyocardial stents and expression plasmid containing the gene-encoding VEGF(165) are applied. 4 weeks later, the animals are sacrificed and echocardiography and pathological analysis have been done.

RESULTSThe density of blood vessel in group ST, VEGF and ST + VEGF are significantly higher than group MI. And capillary density in group ST + VEGF is the highest in these groups statistically. Expression of VEGF was detected in group ST, VEGF and ST + VEGF, but in group VEGF and ST + VEGF the level of expression are higher.

CONCLUSIONCombined use of transmyocardial stent with gene therapy has synthetic effect for the treatment of acute myocardial ischemia in porcine model and can significantly increase the vascular density.

Animals ; Combined Modality Therapy ; Disease Models, Animal ; Genetic Therapy ; Myocardial Infarction ; therapy ; Random Allocation ; Stents ; Swine ; Swine, Miniature ; Vascular Endothelial Growth Factor A ; genetics