Delayed bone healing by collagen membrane in early phase of 4 weeks.

OBJECTIVE: Barrier membranes are important in maintaining space in guided bone regeneration process by preventing downgrowth of epithelial or connective tissue. In this study, the effects of resorbable membranes during the early stages of bone regeneration in rats with impaired bone healing capacity were investigated. STUDY DESIGN: Twenty-eight rats were selected for this study. Half of the animals were selected for radiation therapy before surgical procedure (G3, G4). Animals were assigned into 4 groups (G1-G4). A circular defect was created in the central parietal bone. It was covered with resorbable membrane in G2 and G4. After 4 weeks, the animals were sacrificed. RESULTS: At week 4, the new bone formation was observed around the margin of old bone in G1, G2 and G4 groups. Osteoclast was most abundant in the G1 group (18.3 ± 7.7) and least abundant in the G4 group (7.9 ± 4.7). The mean of osteocalcin levels in blood was the highest in the G2 group and lowest in the G3 group. Only G4 group showed significant difference in Runx2 levels between before-treatment and after- treatment. CONCLUSIONS: Bone healing is adversely affected after radiation therapy. In addition, resorbable membranes can delay healing in the early stages of bone regeneration.

Simultaneous Scalp, Skull, Kidney, and Pancreas Transplant from a Single Donor.

BACKGROUND: Vascularized composite allotransplantation is an emerging field, but the complications of lifelong immunosuppression limit indications. Vascularized composite allotransplantation in solid organ recipients represents a unique opportunity because immunosuppression has already been accepted. This report of a simultaneous scalp, skull, kidney, and pancreas transplant represents both the first skull-scalp transplant and combination of a vascularized composite allotransplantation with double organ transplantation. METHODS: A previous recipient of a kidney-pancreas transplant presented with osteoradionecrosis of the calvaria and a large area of unstable scalp following successful, curative treatment of a scalp tumor. His kidney and pancreas functions were also critically poor. A multidisciplinary, multi-institutional plan was developed to perform a simultaneous scalp, skull, and repeated kidney and pancreas transplantation, all from a single donor. RESULTS: Eighteen months after the patient was listed with the United Network for Organ Sharing, a donor was identified and the multiorgan vascularized composite allotransplantation was performed. Twenty physicians and 15 hours were required to perform donor and recipient procedures. The patient recovered well and was discharged on postoperative day 15. He has had one episode of scalp rejection confirmed by biopsy and treated successfully. His creatinine value is currently 0.8 mg/dl, from 5.0 mg/dl, and his blood glucose levels are normal without supplemental insulin. Aesthetic outcome is very satisfactory. The patient is now 1 year post-transplantation and doing well. CONCLUSIONS: Vascularized composite allotransplantation in solid organ recipients is an expansion of current indications to already immunosuppressed patients. Rejection of the vascularized composite allotransplant without solid organ rejection can occur and is treatable. Methodical planning, an interdisciplinary approach, and careful management of all organs are critical to success. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Effects of laser and ozone therapies on bone healing in the calvarial defects.

This study aims to analyze the effect of the low-level laser therapy (LLLT) and ozone therapy on the bone healing of critical size defect (CSD) in rat calvaria. A total of 30 Wistar male rats were used. A 5-mm-diameter trephine bur was used to create CSD on the right side of the parietal bone of each rat calvarium. Once the bone was excised, a synthetic biphasic calcium phosphate graft material was implanted to all the bone defect sites. The animals were randomly divided into 3 groups as follows: the control group (n = 10), which received no LLLT or ozone therapy; the LLLT group (n = 10), which received only LLLT (120 seconds, 3 times a week for 2 weeks); and the ozone therapy group (n = 10) (120 seconds, 3 times a week for 2 weeks). After 1 month, all the rats were killed, and the sections were examined to evaluate the presence of inflammatory infiltrate, connective tissue, and new bone formation areas. Histomorphometric analyses showed that in the LLLT and ozone groups, the new bone areas were significantly higher than in the control group (P < 0.05). In the LLLT group, higher new bone areas were found than in the ozone group (P < 0.05). This study demonstrated that both ozone and laser therapies had a positive effect on bone formation in rat calvarial defect, compared with the control group; however, ozone therapy was more effective than LLLT (808 nm; 0.1 W; 4 J/cm(2); 0.028 cm(2), continuous wave mode).

Clinical and cellular ionizing radiation sensitivity in a patient with xeroderma pigmentosum.

XP14BR is a cell line derived from a xeroderma pigmentosum (XP) patient from complementation group C. The patient was unusual in presenting with an angiosarcoma of the scalp, treated by surgical excision and radiotherapy. Following 38 Gy in 19 fractions with 6 MEV electrons, a severe desquamation and necrosis of the underlying bone ensued, and death followed 4 years later. The cell line was correspondingly hypersensitive to the lethal effects of gamma irradiation. We had previously shown that this sensitivity could be discriminated from that seen in ataxia-telangiectasia (A-T). The cellular response to ultraviolet radiation below 280 nm (UVC) was characteristic of XP cells, indicating the second instance, in our experience, of dual cellular UVC and ionizing radiation hypersensitivity in XP. We then set out to evaluate any defects in repair of ionizing radiation damage and to verify any direct contribution of the XPC gene. The cells were defective in repair of a fraction of double strand breaks, with a pattern reminiscent of A-T. The cell line was immortalized with the vector pSV3neo and the XPC cDNA transfected in to correct the defect. The progeny derived from this transfection showed the presence of the XPC gene product, as measured by immunoblotting. A considerable restoration of normal UVC, but not ionizing radiation, sensitivity was observed amongst the clones. This differential correction of cellular sensitivity is strong evidence for the presence of a defective radiosensitivity gene, distinct from XPC, which is responsible for the clinical hypersensitivity to ionizing radiation. It is important to resolve how widespread ionizing radiation sensitivity is amongst XP patients.

Histological and TEM examination of early stages of bone healing after Er:YAG laser irradiation.

OBJECTIVE: The aim of this study was to analyze the early healing process of bone tissue irradiated by Er:YAG laser and compare it with that treated by mechanical drilling and CO(2) laser. BACKGROUND DATA: Er:YAG laser has a great potential for cutting hard tissues as it is capable of ablation with less thermal damage. METHODS: Twenty-four male Wistar rats were used for this study. The calvarial bone of rats was exposed and straight grooves were prepared by Er:YAG laser, mechanical bur and continuous wave CO(2) laser. Four rats each were sacrificed at six time points: 10 min, 6 and 24 h and 3, 7, and 14 days post-surgery. Sections were prepared for light and transmission electron microscopic (TEM) observations. RESULTS: Compared to mechanical bur and CO(2) groups, the inflammatory cell infiltration adjacent to the irradiated bone surface, fibroblastic reaction, and revascularization were more pronounced in the Er:YAG laser-irradiated tissues. A cell-rich granulation tissue with fibroblasts and osteoblasts was predominant in 7-day specimens of Er:YAG laser group. Histopathological analysis of 14-day specimens in the Er:YAG group also revealed significantly greater new bone formation, compared with the mechanical bur and CO(2) laser groups. CONCLUSIONS: Initial bone healing following Er:YAG laser irradiation occurred faster than that after mechanical bur and CO(2) laser. Er:YAG laser treatment may be advantageous for wound healing of bone tissue, presumably by providing a favorable surface for cell attachment.

Enhancement of bone formation in rat calvarial bone defects using low-level laser therapy.

OBJECTIVE: To evaluate the effect of low-level laser therapy (LLLT), using a GaAlAs diode laser device, on bone healing and growth in rat calvarial bone defects. STUDY DESIGN: An animal trial of 4 weeks' duration was conducted using a randomized blind, placebo-controlled design. Standardized round osseous defects of 2.7 mm diameter were made in each parietal bone of 20 rats (n=40 defects). The animals were randomly divided into an experimental and a control group of 10 animals each. In the experimental group, a GaAlAs diode laser was applied immediately after surgery and then daily for 6 consecutive days. The control group received the same handling and treatment, but with the laser turned off. Five rats from each group were killed on day 14 and the remainder on day 28 postoperatively. From each animal, tissue samples from one defect were prepared for histochemistry and samples from the contralateral defect for histology. Levels of calcium, phosphorus, and protein were determined by using atomic absorption spectrometry, colorimetry, and photometry, respectively. Student t-test and Mann-Whitney were used for statistical analyses. RESULTS: At both time points the tissue samples from the experimental animals contained significantly more calcium, phosphorus, and protein than the controls. Similarly, histological analyses disclosed more pronounced angiogenesis and connective tissue formation, and more advanced bone formation in the experimental group than in the controls. CONCLUSION: LLLT may enhance bone formation in rat calvarial bone defects.