[The influences on mandibular development after removing the outer cortex of mandibular body in childhood minitype pigs].

OBJECTIVE: To study the influences on mandibular development after removing the outer cortex of mandibular body in childhood minitype pig. METHODS: Six 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. RESULTS: There 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. CONCLUSIONS: There 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.

[The surgical management of unilateral Craniofacial Atrophy and Hypoplasia].

OBJECTIVE: To study the surgical reconstruction of unilateral Craniofacial Atrophy and Hypoplasia. METHODS: According to the etiological factors and severity of the facial deformities, different methods are employed, including bone framework reconstruction, soft tissue transplantation, orthognathic surgery. RESULTS: From September 1998 to August 2004, 42 cases were treated, Include: Hemifacial Microsomia 22 cases, Hemifacial Atrophy 16 cases, unilateral facial hypoplasia due to radiation 4 cases. Miniplate and transplants extrusion occurred on 2 post radiation patients due to poor soft tissue coverage, infection occurred on 1 patient after mandibular ramus reconstruction using autogenous rib and contralateral mandibular outer cortex. The leaving patients recovered well and the facial asymmetry were improved greatly. CONCLUSIONS: Facial asymmetry due to unilateral Craniofacial Atrophy or Hypoplasia is a common and complex condition for surgical management, The surgical plan should be delicated made individually according to the severity of the soft tissue and the underlying bone framework.

Heterogeneity in predisposition of hepatic cells to be induced into pancreatic endocrine cells by PDX-1.

AIM: The role of Pancreatic and Duodenal Homeobox-1 (PDX-1) as a major regulator of pancreatic development determines the function and phenotype of beta cell. In this study, potential plasticity of liver cells into pancreatic endocrine cells induced by PDX-1 was evaluated. METHODS: Human hepatoma cell line HepG2 was stably transfected with mammalian expression plasmid pcDNA3-PDX encoding human PDX-1 gene. Ectopic expression of PDX-1 and insulin were detected by RT-PCR, Western blot and/or immunostaining. PDX-1(+) HepG2 cells were transplanted under renal capsule of STZ-induced diabetic nude mice (n = 16) to examine the inducing effect in vivo. RESULTS: Exogenous PDX-1 transgene was proved to express effectively in HepG2 cell at both mRNA and protein levels. The expression of endogenous insulin and some beta cell-specific differentiation markers and transcription factors were not induced in PDX-1(+) HepG2 cells. When transplanted under renal capsule of STZ-induced diabetic nude mice, PDX-1(+) HepG2 cells did not generate insulin-producing cells. These data indicated that stable transfected PDX-1 could not convert hepatoma cell line HepG2 to pancreatic cells in vitro or in vivo. Mature hepatocytes might need much more complicated or rigorous conditions to be shifted to insulin-producing cells. CONCLUSION: The expression of exogenous PDX-1 is not sufficient to induce relatively mature hepatocytes differentiating into insulin-producing cells.

[Expression of nestin and neurogenin 3 in the human fetal pancreas].

OBJECTIVE: To examine the expression of nestin and neurogenin 3 (Ngn3), the markers of pancreatic stem cells, in the human fetal pancreas. METHODS: The human fetal pancreas tissue of 12 and 14 weeks were examined for the expression of nestin and Ngn3 using the techniques of immunofluorescence dye and RT-PCR. RESULTS: Both nestin and Ngn3 expressed widely in 12 and 14 weeks before in human fetal pancreatic tissue. In these positive cells there was no co-expressing insulin or glucagon. There were nestin and Ngn3 co-expressing cells in ducts but not in the islets. The results of RT-PCR also indicated the expression of nestin and Ngn3. CONCLUSIONS: There was no expression of the markers of mature endocrine cells in the nestin and Ngn3 positive cells, and they were the marks of no-differentiation cells in the human fetal pancreatic tissue.