Ischemia preconditioning protects rat submandibular glands from ischemia/reperfusion injuries.

To investigate the effects of ischemia/reperfusion on rat submandibular glands without denervation and the possible protective effects of ischemia preconditioning on the glands that experienced ischemia/reperfusion, in-situ ischemia/reperfusion and ischemia preconditioning experimental models of submandibular glands of healthy male Wistar rats were conducted. For ischemia/reperfusion groups, the glands were subjected to 90 min of ischemia without denervation, followed by 1, 12, 24, or 72 h of reperfusion. Ischemia preconditioning was achieved by 3 min of ischemia following 3 min of reperfusion, performed three times before ischemia/reperfusion. Salivary secretion, histological changes, alterations of tight junctions, myeloperoxidase activity, cellular apoptosis, and reactive oxygen species levels were detected. In ischemia/reperfusion glands, rising acute-inflammation responses, reduced tight-junction width, and increased myeloperoxidase activity, reactive oxygen species levels, and apoptotic cell numbers were observed, along with secretory dysfunction, especially at 1 and 12 h post-reperfusion, which seemed to gradually return to normal by 72 h post-reperfusion. In contrast, ischemia preconditioning showed the potential to ameliorate the injury-stress responses caused by ischemia/reperfusion. Our study revealed that ischemia/reperfusion could cause a series of injury-stress responses and ultimately lead to hyposecretion, independently of the parasympathetic nerve supply, which might play an important role in the early-phase dysfunction of the transplanted glands. Ischemia preconditioning could protect the involved glands and improve ischemia/reperfusion-induced hyposecretion.

[Surgical treatment of tonsillar cancer].

OBJECTIVE: To study the surgical treatment of tonsillar cancer. METHODS: Twenty-four patients with tonsillar cancer were treated with surgery and postoperative radiotherapy. The choice of surgical procedure was decided on the condition of the lesion. The tumor was resected through the transoral approach, mandibular swing approach, mandibular resection approach or hyoid approach. Surgical defect was repaired by pectoralis major myocutaneous flap, sternohyoid myofascial flap, tongue flap or soft palate flap. RESULTS: The 3- and 5-year survival rates were 76.0% and 60.8%. Function of chewing, deglutition, respiration and speech was restored well. CONCLUSION: Method of total resection of the tonsillar carcinoma through the optimum approach is best chosen according to the condition of the lesion, while preserving the oropharyngeal function. When combined with postoperative radiotherapy, the survival rate and quality of life of patients can be improved.

New treatment strategy for granulomatous epulis: intralesional injection of propranolol.

Epulis is a relapsable lesion in gingiva without specific treatment for its unexplained pathogenesis. Nowadays, surgical excision is the most popular method of treatment. To prevent recurrence, it is necessary to resect diseased tissues thoroughly, and even to remove the involved teeth. However, this may cause functional and cosmetic deformities. Therefore, it is urgent to find a new therapy without severe side effects. Infantile hemangioma is a common benign pediatric tumor which shares many features with epulis, such as rich vascularity, high incidence of female patients, high hormone level and similar treatments. A recent study showed that propranolol, a beta adrenergic receptor (ß-AR) antagonist, was effective as treatment for infantile hemangioma. Our preliminary work showed that mRNA and protein levels of ß2-AR were higher in epulis than in adjacent tissue. Therefore, we hypothesize that intralesional injection of propranolol may be useful as epulis treatment. Further work need to be done to confirm the safety and therapeutic effect of the treatment. After that, this specific ß2-AR antagonist may be the first choice for epulis treatment.

Familial multiple odontogenic keratocysts.

Multiple odontogenic keratocysts (OKCs) are principle features of nevoid basal cell carcinoma syndrome (NBCCS; Gorlin-Goltz syndrome). NBCCS is a genetic disorder transmitted by an autosomal dominant gene with variable expressivity, which is important to recognize when a patient has multiple OKCs. The cysts of the jaws are among the most common findings. Another feature is a certain appearance of the face, such as: large calvaria, high-arched eyebrows, broad nasal root, and mild hypertelorism. Before-therapy diagnosis is, therefore, as important as after-therapy diagnosis. Genetic counseling and examination may also be indicated. The purpose of this paper was to present a family case report of nevoid basal cell carcinoma syndrome with multiple odontogenic keratocysts. The features identified by these combined clinical, imaging, and histologic findings are described, along with a brief mention of the family history and a review of the literature.

[Effect of different nanophase hydroxyapatite particles on osteoblasts metabolism].

PURPOSE: To compare two different structural nanophase hydroxyapatite(HA) particles on the proliferation activity and functions of osteoblasts. METHODS: Primary culture of osteoblasts from rat calvaria was established and then cultured on the coatings of different size of nano particles (groupI 20-40nm,group II 70-100nm), the HA coatings without nano-particles was used as control group. Proliferation activity, protein content and synthesis of alkaline phosphatase(ALP) by osteoblasts were examined by MTT assay, coomassic brilliant blue method and PNPP test, and statistical significance was assessed by multiple comparison (q test, SNK) in one-way analysis of variance (ANOVA) with SPSS10.0 software package. RESULTS: Osteoblasts grew well on HA coatings. MTT assay demonstrated that there was significant difference between group I and group II at 6th day and 8th day (P<0.05).At first half stage(5th day and 10th day) ALP activity test showed no significant difference between group I and groupII (P>0.05) and as the culture going on(15th day and 20th day), there was significant difference between the two groups (P<0.05). Coomassic brilliant blue method showed that there was significant difference between group I and group II from 5th day to 20th day (P<0.05). CONCLUSION: The diameter of nano-particles on the HA coatings could influence the proliferation activity and functions of the osteoblasts. The nano-particles of similar size with HA crystal in vivo showed better cytocompatibility.

[Effect of bone morphogenetic proteins-2 on mandibular distraction osteogenesis in rabbits].

OBJECTIVE: To investigate the Effect of recombinant adenovirus vectors containing human Bone morphogenetic proteins-2 (Ad-hBMP-2) on the for mandibular distraction osteogenesis (DO) in rabbits. METHODS: Twenty-four New Zealand white rabbits were randomly divided into experimental group, and control group and underwent mandibular distraction osteogenesis. After 5 days latency, the distracters were activated at a speed of 0.5 mm every 12 hours for 7 days, then on the first day in the consolidation period, the distraction gaps of experimental group were injected with 0.2 ml Ad-hBMP2 10(12) pfu/L, while the animals of control group were injected with 0.2 ml Ad-EGFP 10(12) pfu/L. At the 7 th and 28 th day of consolidation period, specimens were obtained, X-ray and histomorphology were performed. The bone density and the quantity of new bone formation in the distraction gaps were observed and compared between the two groups at different consolidation period. RESULTS: Ad-hBMP-2 treated specimens demonstrated an increased amount of new bone formation CONCLUSIONS: Adenovirally-mediated delivery of BMP-2 can locally increase bone deposition during DO, which may potentially shorten the consolidation period.

[Clinical study of oral and maxillofacial malignancies associated with multiple primary malignant neoplasms].

OBJECTIVE: To study the clinical characteristics, diagnosis and treatment strategy of oral and maxillofacial malignancies in multiple primary malignant neoplasms (MPMNs). METHODS: 21 cases of oral and maxillofacial malignancies associated with MPMNs admitted to our hospital between 1985 and 2000 were studied respectively. RESULTS: There were 44 malignant cases in the 21 MPMNs patients. Among the 44 cases, there were 24 cases in alimentary and respiratory tract such as oral, pharynx, esophagus, stomach and lung, and 10 cases in salivary gland, breast and female reproductive system. There were 25 cases malignant neoplasms in oral and maxillofacial region where squamous cell carcinoma was the most common pathologic type, secondly adenoid cystic carcinoma. In oral and maxillofacial region, MPMNs were often found in tongue, parotid and submandibular gland, buccal mucosa and gingival. CONCLUSION: Tongue and salivary gland were the common locations with MPMNs, and they were closely associated with alimentary and respiratory tract. Patients with malignancies of oral and maxillofacial region associated with MPMNs must be submitted to a long-term and careful follow-up. For female patients, breast and female reproductive system should be examined specially. Regular follow-up, early detection, early diagnosis, active and effective treatment can help to improve the survival quality of MPMNs patients.

[Evaluation of peri-implant augmentation with collected bone].

PURPOSE: To determine the amount of bone harvested from dental implant osteotomies with aspeo 12000 bone collector, to characterize the nature of the debris, and to evaluate the histological viability and clinical effect of peri-implant augmentation with immediate implantation of collected bone. METHODS: From May 2004 to Oct 2005, 15 recruited patients without peri-implant imperfections underwent 18 ITI implants installation. During the implant bed preparation, 18 samples of bone were collected using the instrument and an analysis of variance was used to determine if there were statistical differences between female versus male, maxilla versus mandible, anterior versus posterior alveolar bone. After decalcification, the material from each sample was fixed in paraffin wax and stained with haematoxylin and eosin, all sections were examined by optical microscope and the proportion of bone was established histomorphometrically. During the time, 12 defects occurred in 11 patients when 16 dental implants were installed, and all the defects were augmented with collected bone debris simultaneously. RESULTS: About 93% volume of 'wet' bone could be obtained from one dental implant osteotomy, and there were no statistical differences between female and male, maxilla and mandible, anterior and posterior alveolar bone. Histological observation showed that all samples contained bone and coagulum, the mean bone proportion was 94.2%. 3 to 6 months after surgery, the defects were successfully augmented, and during the secondary operation, bone growth was found over the defects. CONCLUSION: The use of bone collectors is a good method for obtaining material to fill small bone imperfections in dental implantation.

[Experimental study of mandibular periosteal distraction in rabbits].

OBJECTIVE: To investigate a novel technique for new bone formation--periosteal distraction osteogenesis. METHODS: A custom made periosteal distraction device was fixed to bilateral surface of the mandible in three rabbits. Periosteal distraction was performed on the left side of the mandible, the right side of the mandible served as the control. The animals were sacrificed at the end of distraction process. All the specimens were X-rayed and histologically examinated. RESULTS: All three animals survived with no obvious complications. Both in mass specimens and X-rays, there showed new bone formation on the distracted side of the mandible. In histological examinations, there was osteoblast-like cell infiltration and bone tissue formation in the distracted area. CONCLUSION: Periosteal distraction osteogenesis can provide a novel technique for the repair of bone defects.

[Repair of mandibular central fissures in rabbits with hBMP-2 gene modified tissue engineered bone].

PURPOSE: To evaluate the effectiveness of the tissue engineered bone substitute loaded with periosteal-derived osteoblasts (POBs) transfected by adenovirus mediated human bone morphogenetic protein-2 gene (Ad-hBMP-2) in the repair of rabbit mandibular central fissures. METHODS: 45 rabbits with the soft tissue in the mandibular central fissures removed were randomly divided into 5 groups, group I: Ad-hBMP-2 transfected POBs/bioglass group (n=10); group II: adenovirus mediated enhanced green fluorescent protein (Ad-EGFP) gene transfected POBs/bioglass group (n=10); group III: untransfected POBs/bioglass group (n=10); group IV: single bioglass group (n=10); group V: control group (n=5). The above bone substitutes were implanted in the rabbit mandibular central fissures respectively except group V. The samples were studied by gross, X-ray, histomorphology, histomorphometrical analysis and biomechanics after 2, 4, 8, 12 weeks respectively. One-way ANOVA was used for statistical analysis. RESULTS: In gross view, the rabbit mandibular central fissures in group I were replaced by new bone including cortical bone from the 4th week. X-ray examination showed that the higher bone density was found in the rabbit mandibular central fissures of group I 4 to 8 weeks after implantation. Histomorphometrical analysis showed much more new bony callus in group I than in other groups (P<0.01). The maximal anti-bending load and bending rigidity of the implanted bone substitute of group I were significantly higher than those of group II, III and IV (P<0.01). CONCLUSION: The tissue engineered bone substitute loaded with POBs transfected by human BMP-2 gene could get the best result in the repair of rabbit mandibular central fissures, therefore, it is likely to be used in the repair of alveolar clefts.

[Study of the expression of integrin alphaV beta3 in mandibular distraction osteogenesis].

OBJECTIVE: To investigate the expression and distribution pattern of Integrin alphaV beta3 (ItgalphaV beta3) in course of distraction 44 adults New Zealand white osteogenesis and to quest for the function of ItgalphaV beta3 in distraction osteogenesis (DO). METHODS: rabbits were selected and divided randomly into 3 groups: DO, bone fracture and normal group. There were 20, 20 and 4 rabbits in each group separately. Animal models were established and animals were killed at different time points. Sections were stained by IHC method. Distribution and expression pattern of ItgalphaV beta3 were observed by semi-quantitative technique, and the results were managed with statistic methods. RESULTS: The expression of ItgalphaV beta3 was found both in the DO and bone fracture groups. The positive staining was seen mainly in vascular endothelial cells on cytomembrane and in cytoplasm. The staining intensity of group of DO was higher than that of the bone fracture group. CONCLUSION: ItgalphaV beta3 plays an important role in promoting the process of DO.

[The establishment of an animal model of bilateral mandibular distraction osteogenesis in rabbits].

PURPOSE: To establish an animal model of bilateral mandibular distraction osteogenesis in rabbits. METHODS: 16 adult male white New Zealand rabbits were divided into 4 groups randomly, 4 in each group. Osteotomy was performed on mandible bilaterally before the first premolar. Bone stumps were repositioned and fixed with distractors. After 7 days of latency period, distraction was initiated at a rate of 1mm/d for 7 days. Then distractors were held in place for days. Animals were killed at different time points, and specimens were taken for X-ray and histology examination. RESULTS: The mandibles were lengthened successfully. The distraction gaps were filled with regenerated bone tissue. CONCLUSION: The method in this study is practicable and repeatable which could be used to establish an animal model of mandibular distraction osteogenesis in rabbits.

[The experimental study of cryopreserved osteoblasts combined with BGC repairing mandibular defects in rabbits].

OBJECTIVE: The purpose of this study was to observe the biological characteristics of cultured Periosteal-derived Osteoblasts (POBs) preserved in liquid nitrogen in vitro, and to preliminarily study the osteogenetic capability of bioactive glass ceramic (BGC) combined with POBs. METHODS: The cryopreserved cells were cultured in DMEM medium and examined by morphological and histological assay. The POBs growing well in vitro were seeded into the porous BGC materials. A week later, the combined materials were implanted into the bone defects of rabbits' mandibular, the control groups were implanted into the single BGC (no cells). After 2, 4, 8, 12 weeks of operation, the specimens were respectively excised and examined by X-ray and histological chemistry. RESULTS: The cryopreserved POBs grew well in vitro and also had the tipical characteristics of mature osteoblasts. Cultured with BGC materials, the cells could attach, grow and proliferate well on the surface of most endoporous. After 4 weeks of operation, the transplanted osteoblasts began to form new osteoid or bone tissue in most pores of implanted BGC, and the bone defects were repaired better and earlier. CONCLUSION: It was practical to use the cryopreserved osteoblasts for further study on bone tissue engineering. It suggested that the "life active" bone would get more application and play a more important role in bone restoration and reconstruction.

[The ALP activity of cultured dental coronal and root pulp cells in vitro].

PURPOSE: To compare the ALP activity in human dental coronal and root pulp,and investigate the localization of dental pulp stem cells in the dental pulp. METHODS: The human dental root and coronal pulp cells were cultured in tissue-explant method, the 5th generation of cells in good growth condition were subcultured with conditioned media (20% DMEM + 10 nmol/L + dexamethaone + 50mg/L ascorbic acid) to induce mineralization. At the days of 5, 10, 15 after inducing, Gomori alkaline phosphatase stain was used to investigate alkaline phosphatase (ALP) activity in root and coronal pulp cells. RESULTS: Positive staining was found in both root and coronal cells, the ALP activity was equal at 5 days of incubation, but higher in root pulp cells than that of coronal pulp cells after 10 and 15 days of incubation. CONCLUSIONS: ALP activity in dental root pulp is higher than that in coronal pulp. DPSCs may exist in both dental root and coronal pulp, and the density of DPSCs is higher in the root pulp than the coronal pulp.

[Investigation of primary cell culture for dental pulp: comparing of coronal pulp and root pulp].

PURPOSE: To compare and establish an ideal method for the culture of human primary dental coronal and root pulp cells. METHODS: The whole dental pulp tissues were obtained from healthy and young human teeth extracted for orthodontic purposes. The cells in coronal and root pulp were separately cultured by the tissue explant and tissue explant-collagenase digestion(0.1% type I collagenase) methods. By evaluating the attachment efficiency,viability and the successfulness of the cultured cells, the optimal primary cell culture process of human dental coronal and root pulp was determined. RESULTS: The tissue explant culture had more successfulness,more viability and less attachment efficiency than that of tissue explant-collagenase digestion method in the culture of human coronal and root dental pulp cells. CONCLUSIONS: Tissue explant method was superior to tissue explant-collagenase digestion method for the culturing of human dental coronal and root pulp cells. The ideal method for dental coronal and root pulp cells was established in this study.

[The characteristics of cultured dental pulp cells and the localization of dental pulp stem cells].

PURPOSE: This study was aimed to investigate the localization of dental pulp stem cells (DPSCs) by comparing the characteristics of cultured dental pulp cells in coronal and root pulp. METHODS: Human dental coronal and root pulp cells were cultured in tissue-explant method, the cell culture successfulness, attachment efficiency, cell viality, morphology, proliferation pattern, and the mineralization ability were observed, the localization of DPSCs was investigated in the functional respect of DPSCs. RESULTS: The human dental root pulp cells have more culture successfulness,more attachment efficiency,more cell viality, more primary characteristics, and stronger induced mineralization ability than that of coronal pulp cells. Root and coronal pulp cells showed same proliferation patterns. CONCLUSIONS: DPSCs may exist in both dental root and coronal pulp, and the density of DPSCs in the root pulp may be higher than the coronal pulp.