Creation of forest edges has a global impact on forest vertebrates.

Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

HCRP1 expression status is a significant prognostic marker in oral and oropharyngeal cancer.

OBJECTIVE: The hepatocellular carcinoma-related protein 1 (HCRP1) is a key factor in the degradation of the epidermal growth factor receptor. In this study, we assessed the prognostic significance of HCRP1 expression in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). METHODS: HCRP1 expression was determined by immunohistochemistry on tissue biopsy sections of 111 patients with locally advanced OOSCC undergoing neoadjuvant chemoradiotherapy followed by surgery. The Kaplan-Meier method and Cox regression models were used for survival analyses. RESULTS: Low HCRP1 expression was associated with poor recurrence-free survival (P = 0.046) and overall survival (P = 0.03). Multivariate analysis revealed that low HCRP1 expression remained an independent risk factor for relapse (HR 2.98, 95% CI 1.19-7.49, P = 0.02) and death (HR 3.04, 95% CI 1.19-7.79, P = 0.02). CONCLUSION: Low HCRP1 expression was found to be of adverse prognostic significance in patients with OOSCC who received preoperative chemoradiotherapy.

Uptake of (18)F-FLT and (18)F-FDG in primary head and neck cancer correlates with survival.

UNLABELLED: The aim of the study was to determine the practicability of (18)F-FLT in tumours of the head and neck area in terms of visualization, a possible correlation between FLT uptake and proliferation fraction as determined by Ki-67 immunostaining, and if tumoural FLT-uptake has a prognostic meaning, as determined by a correlation to patient survival time. Results were compared to (18)F-FDG. PATIENTS, METHODS: 20 patients with previously untreated lesions of the head and neck area, which were clinically highly suspicious to be malignant, underwent PET scans with (18)F-FLT and (18)F-FDG, a CT of the head and neck area, and a biopsy. Tumour tracer uptake was determined by standardized uptake value (SUV) normalized to body weight and /non-tumor ratios (T/N). (18)F-FDG and (18)F-FLT uptake were compared with histopathologic and immunohistochemical results. RESULTS: 19 patients had malignant tumours; one patient had a benign cystadenoma (so called Warthin's tumour) of the parotid gland. One negative lesion turned out to be a malignant T1 stage squamous cell carcinoma in both PET scans, the Warthin's tumour was false positive with (18)F-FDG but showed only faint uptake with (18)F-FLT, resulting in a sensitivity of 95 % for both tracers. Of all lesions, maximum SUVs of (18)F-FLT ranged from 1.53 to 11.70 (mean +/- SD 5.81 +/- 2.28) those of FDG from 2.63 to 16.50 (mean +/- SD 8.91 +/- 3.58), p < 0.001. (18)F-FLT-T/N ranged from 0.94 to 5.85 (mean +/- SD, 3.18 +/- 1.21), (18)F-FDG-T/N was from 0.92 to 7.50 (mean +/- SD, 3.6 +/- 1.74), n.s. The mean survival time was 18 months in a maximum follow up time of 36 months. A significant correlation between both PET tracers and survival was detected, but no correlation between the amount of Ki-67 positive cells and FLT. CONCLUSION: In head and neck cancer in the primary setting (18)F-FLT does not provide additional visual information in comparison to (18)F-FDG.(18)F-FLT uptake is inversely correlated with patient survival, as well as (18)F-FDG.

Biodegradable polymer membrane used as septal splint.

The treatment of a crooked nose is one of the most challenging rhinoplastic procedures. Correction of the abnormally curved or fractured septum has been reported using mostly scoring techniques, septoplasty and submucous resection techniques; cartilaginous spreader grafts can also be sutured to the distorted septum. Extracorporal septal straightening and repositioning/refixation is another useful but difficult technique. A common problem of septal cartilaginous grafting techniques is to harvest enough straight cartilage to correct the deformity. (Other donor sites such as rib cartilage are used, but harvesting additional cartilage is a time-consuming procedure and carries the risk of donor site morbidity.) Recent studies have been published using alloplastic internal splinting of the deformed septum. The use of poly p-dioxanone foils and porous polyethylene has been suggested before. In this study, a novel grafting material, a PolyMax membrane that has potential advantages over both materials, is presented. This is a porous biodegradable polymer made out of 70:30 poly(L-lactide-co-D,L-lactide) that remains stable for at least 7 months. Poly p-dioxanone loses its stability after only 2 months, whereas porous polyethylene is a permeable material that is controversial due to possible complications in cases of membrane exposure and infection. In this preliminary report the PolyMax membrane was used successfully in 3 patients.

The challenge of teaching undergraduates evidence-based veterinary medicine.

The Royal College of Veterinary Surgeons now lists 'How to evaluate evidence' as a day one competence for newly qualified vets. In this article, representatives from each of the veterinary schools in the UK discuss how the challenge of delivering and assessing the concepts of evidence-based veterinary medicine in a crowded undergraduate curriculum can be met.

Fixation of zygomatic fractures with a biodegradable copolymer osteosynthesis system: short- and long-term results.

Biodegradable osteosynthesis devices can be viewed as addition to, not yet replacement for conventional metal osteosynthesis materials. In a series of 65 patients with zygomatic fractures, a short-term complication/sequelae rate of 22.8% and a long-term complication rate of 9.4% were recorded. Lactosorb plates, panels and screws were the only devices used for osteosynthesis. All complications associated with the biodegradable material could be considered minor and were resolved by the use of minor surgical procedures or conservative measures. The results of this study indicate that treatment of zygomatic fractures with biodegradable osteosynthesis material has no major long-term adverse effects beyond the total material resorption time.

Invitro study of adherent mandibular osteoblast-like cells on carrier materials.

Augmentation of the craniofacial region is necessary for many aesthetic and reconstructive procedures. Tissue engineering offers a new option to supplement existing treatment regimens. In this procedure, materials composed of hydroxyapatite (HA), of synthetic or natural origin, are used as scaffolds. The aim of this study was to evaluate the effects of three HA materials on cultured human osteoblasts in vitro. Explant cultures of cells from human alveolar bone were established. Human osteoblasts were cultured on the surface of HA calcified from red algae (C GRAFT/Algipore), deproteinized bovine HA (Bio-Oss) and bovine HA carrying the cell binding peptide P-15 (Pep Gen P-15). Cultured cells were evaluated with respect to cell attachment, proliferation and differentiation. Cells were cultured for 6 and 21 days under osteogenic differentiation conditions, and tissue-culture polystyrene dishes were used as control. The ability of cells to proliferate and form extracellular matrix on these scaffolds was assessed by a DNA quantification assay, protein synthesis analysis and by scanning electron microscopical examination. Osteogenic differentiation was screened by the expression of alkaline phosphatase. The osteoblastic phenotype of the cells was monitored using mRNA levels of the bone-related proteins including osteocalcin, osteopontin and collagen Type I. We found that cells cultured on C GRAFT/Algipore) and Pep Gen P-15 showed a continuous increase in DNA content and protein synthesis. Cells cultured on Bio-Oss showed a decrease in DNA content from Day 6 (P < 0.05) to Day 21 (P < 0.0001) and protein synthesis on Day 21 (P < 0.005). Alkaline phosphatase activity increased in cells grown on C GRAFT/Algipore and Pep Gen P-15 in contrast to cells grown on Bio-Oss, in which the lowest levels of activity could be observed on Day 21 (P < 0.05). Reverse transcriptase polymerase chain reaction analysis confirmed the osteoblastic phenotype of the cells grown on all three materials throughout the whole culture period. The results of our in vitro study show that the differences in metabolic activity of cells grown on HA materials are directly related to the substrate on which they are grown. They confirm the excellent properties of HA carrying the cell binding peptide P-15 and HA calcified from red algae as used in maxillofacial surgery procedures.

Basic research and 12 years of clinical experience in computer-assisted navigation technology: a review.

Computer-aided surgical navigation technology is commonly used in craniomaxillofacial surgery. It offers substantial improvement regarding esthetic and functional aspects in a range of surgical procedures. Based on augmented reality principles, where the real operative site is merged with computer generated graphic information, computer-aided navigation systems were employed, among other procedures, in dental implantology, arthroscopy of the temporomandibular joint, osteotomies, distraction osteogenesis, image guided biopsies and removals of foreign bodies. The decision to perform a procedure with or without computer-aided intraoperative navigation depends on the expected benefit to the procedure as well as on the technical expenditure necessary to achieve that goal. This paper comprises the experience gained in 12 years of research, development and routine clinical application. One hundred and fifty-eight operations with successful application of surgical navigation technology--divided into five groups--are evaluated regarding the criteria "medical benefit" and "technical expenditure" necessary to perform these procedures. Our results indicate that the medical benefit is likely to outweight the expenditure of technology with few exceptions (calvaria transplant, resection of the temporal bone, reconstruction of the orbital floor). Especially in dental implantology, specialized software reduces time and additional costs necessary to plan and perform procedures with computer-aided surgical navigation.

Preoperative radiochemotherapy and radical resection for stages II-IV oral and oropharyngeal cancer: outcome of 222 patients.

To analyse survival and locoregional control in patients with advanced oral and oropharyngeal squamous cell carcinoma (SCC) after multimodal therapy with preoperative radiochemotherapy (RCT) and radical surgery. We included in this analysis 222 patients who underwent multimodal therapy between 1990 and 2000. Eligible were patients with UICC disease stages II-IV (T2: 33.3%; T3: 12.6%; T4: 54.1%; N0: 45.9%; N1: 17.6%; N2: 33.3%; N3: 3.2%; stage II: 21.1%; stage III: 14.9%; stage IV: 64%). Patients received preoperative radiochemotherapy consisting of Mitomycin C (15-20 mg/m2, day 1) plus 5-Fluorouracil (750 mg/m2/24 h-infusion, days 1-5) and concomitant radiotherapy for a total dose of 50 Gy. Radical locoregional en bloc-resection according to the pretherapeutic tumour extension was carried out in all patients. After a median surveillance period of 72.3 months (24-152 months), 131 patients (59%) were alive, and 91 (41%) patients died; 12 (5%) of them died postoperatively, 46 (21%) due to tumour recurrence, and 33 (15%) deaths were not directly related to the primary tumour. Overall survival probability was 76% after 2 years, and 62% after 5 years. Two- and 5-year local control probability were 88 and 81%, respectively. Regarding the high percentage of stage IV disease in the reported patients, the multimodal concept is an effective therapy offering excellent survival and local control probability.

Preoperative radiochemotherapy and radical resection for stages II to IV oral and oropharyngeal cancer: grade of regression as crucial prognostic factor.

The purpose of this study was to assess the prognostic value of histological response to preoperative radiochemotherapy in an established multimodal therapy concept for advanced oral and oropharyngeal cancer. Two hundred and twenty-two patients who underwent preoperative radiochemotherapy (RCT: 50 Gy, mitomycin C and fluorouracil) and radical surgery were retrospectively evaluated. Resected tumours of all patients were histologically analysed and response to RCT was classified in histopathological grades of regression (RG). In a multivariate statistical analysis, RG was compared with established factors regarding their predictive value for overall and disease-specific survival. The 5-year overall survival probability in the different groups of histopathological regression grades were: RG1 (no vital tumour): 73.4%, RG2 (minimal tumour remnants encompassing less than 5%): 72.1%, RG3 (5-50% vital tumour cells): 41.9%, RG4 (more than 50% vital tumour): 37.9%. For disease-specific survival probability no significant differences were found between both groups of "responders" (RG1 and RG2) nor between "non-responders" (RG3 and RG4), whereas responders and non-responders differed significantly from each other (log-rank test; p < 0.001). T-classification, N-classification and disease stage, histological grading, tumour site, age, and sex had less prognostic value than RG in a Cox regression model. In the neoadjuvant multimodal therapy concept, histological response to preoperative RCT is a crucial prognostic factor even when surgical R0-resection is accomplished. Thus, non-responders have to be regarded as high-risk patients for recurrence and may benefit from further therapy.

Distraction osteogenesis with subperiosteal devices in edentulous mandibles.

Nine patients with severely atrophic edentulous mandibles were treated by distraction osteogenesis with subperiosteal distractors for vertical augmentation of the anterior alveolar bone before insertion of implants. All the patients had severe complications and we conclude that the use of subperiosteal devices for vertical augmentation of edentulous mandibles is hazardous and offers no advantage over other surgical methods.

Tricalcium phosphate-based biocomposites for mandibular bone regeneration--A histological study in sheep.

The present study investigated the suitability of three different absorbable biocomposites for the repair of critical sized bone defects created at the mandibular angle of adult sheep. Each biocomposite was composed of a three-dimensional individualized polylactide scaffold, containing a tricalcium phosphate biomaterial (chronOS). Either autologous bone marrow (chOS/BoneMarrow) or coagulation factor XIII (chOS/FactorXIII) was added to the biomaterial for osteopromotion. Venous whole blood (chOS/Blood) added to the biomaterial served as a control. A total of 18 adult sheep were used for implantation studies, subdivided into three groups of six animals each. After 12 weeks of observation, the animals were sacrificed and the mandibles were retrieved for qualitative and quantitative histologic assessment within three regions of interest (transitional zone, center, and periphery) throughout the biocomposites. Successful bone regeneration was defined by the absence of scaffold deformation and the presence of new bone formation within the biocomposites. In histomorphometry, only chOS/BoneMarrow showed elevated area fractions of newly formed bone in all regions of interest (transitional zone 50.7 ± 7.5, center 31.9 ± 9.3, periphery 23.1 ± 13.5). This led to preservation of the macroscopic scaffold structure in all specimens. Zero hurdle regression confirmed this by validating the factor biocomposite as significant (p < 0.001) for regeneration success. In our experiment, chOS/BoneMarrow was the only biocomposite passing the hurdle of regeneration in all three regions of interest. In contrast, bone formation was less pronounced and uniform in chOS/FactorXIII and chOS/blood-containing specimens. In these groups, scaffolds showed obvious to significant deformation. Overall, autologous bone marrow showed the most promising results in our experimental setting. As opposed to reports in the literature, we could not confirm the suitability of coagulation factor XIII to promote bone formation, since bone formation rates were comparable only to those of the control venous blood.

Inhibited methionine incorporation in human squamous carcinomas of the oral cavity as a measure for response to 5-fluorouracil.

Human epithelial cells and fibroblasts from malignant tumors and healthy tissues of the oral cavity were exposed in vitro to increasing concentrations of 5-fluorouracil. In order to determine whether the two cell types showed a difference in uptake, accumulation was measured over time using tritiated fluorouracil. Maximal drug uptake occurred in highly proliferative epithelial cells from cancerous tissue at 3 h, whereas fibroblasts from the same tissue and other cell types from healthy tissue exhibited a steadily increasing uptake over a long period of time. By use of [3H]methionine, a direct correlation could be demonstrated between the amount of incorporated drug and the fall in the rate of de novo protein synthesis. Furthermore, suppression of protein synthesis was closely related to the inhibition of cell division. These results indicate that the level of de novo protein synthesis can be a direct measure of the anticancer effect of fluorouracil.

Quantitative analysis of factors affecting intraoperative precision and stability of optoelectronic and electromagnetic tracking systems.

This study aims to provide a quantitative analysis of the factors affecting the actual precision and stability of optoelectronic and electromagnetic tracking systems in computer-aided surgery under real clinical/intraoperative conditions. A "phantom-skull" with five precisely determined reference distances between marker spheres is used for all measurements. Three optoelectronic and one electromagnetic tracking systems are included in this study. The experimental design is divided into three parts: (1) evaluation of serial- and multislice-CT (computed tomography) images of the phantom-skull for the precision of distance measurements by means of navigation software without a digitizer, (2) digitizer measurements under realistic intraoperative conditions with the factors OR-lamp (radiating into the field of view of the digitizer) or/and "handling with ferromagnetic surgical instruments" (in the field of view of the digitizer) and (3) "point-measurements" to analyze the influence of changes in the angle of inclination of the stylus axis. Deviations between reference distances and measured values are statistically investigated by means of analysis of variance. Computerized measurements of distances based on serial-CT data were more precise than based on multislice-CT data. All tracking systems included in this study proved to be considerably less precise under realistic OR conditions when compared to the technical specifications in the manuals of the systems. Changes in the angle of inclination of the stylus axis resulted in deviations of up to 3.40 mm (mean deviations for all systems ranging from 0.49 to 1.42 mm, variances ranging from 0.09 to 1.44 mm), indicating a strong need for improvements of stylus design. The electromagnetic tracking system investigated in this study was not significantly affected by small ferromagnetic surgical instruments.

Systematic distortions in magnetic position digitizers.

Medical devices equipped with position sensors enable applications like image guided surgical interventions, reconstruction of three-dimensional 3D ultrasound (US) images, and virtual or augmented reality systems. The acquisition of three-dimensional position data in real time is one of the key technologies in this field. The systematic distortions induced by various metals, surgical tools, and US scan probes in different commercial electromagnetic tracking systems were assessed in the presented work. A precise nonmetallic six degree-of-freedom measurement rack was built that allowed a quantitative comparison of different electromagnetic trackers. Also, their performance in the presence of large metallic structures was quantified in a phantom study on an acrylic skull model in an operating room (OR). The trackers used were alternating current (ac) and direct current (dc) based systems. The ac trackers were, on average, distorted by 0.7 mm and 0.5 degree by metallic objects positioned at a distance greater than 120 mm between the geometrical center of the sample and the sensor. In the OR environment, the ac system exhibits mean errors of 3.2 +/- 2.4 mm and 2.9 degrees +/- 1.9 degrees. The dc trackers are more sensitive to distortions caused by ferromagnetic materials (averaged value: 1.6 mm and 0.5 degree beyond a distance of 120 mm). The dc tracker shows no distortions from other conductive materials but was less accurate in the OR environment (typical error: 6.4 +/- 2.5 mm and 4.9 degrees +/- 2.0 degrees). At distances smaller than approximately 100 mm between sample and sensor error increases quickly. It is also apparent from our measurements that the influence of US scan probes is governed by their shielding material. The results show that surgical instruments not containing conductive material are to be preferred when using an ac tracker. Nonferromagnetic instruments should be used with dc trackers. Static distortions caused by the OR environment have to be compensated by precise calibration methods.

Calibration of tracking systems in a surgical environment.

The purpose of this paper was to assess to what extent an optical tracking system (OTS) used for position determination in computer-aided surgery (CAS) can be enhanced by combining it with a direct current (dc) driven electromagnetic tracking system (EMTS). The main advantage of the EMTS is the fact that it is not dependent on a free line-of-sight. Unfortunately, the accuracy of the EMTS is highly affected by nearby ferromagnetic materials. We have explored to what extent the influence of the metallic equipment in the operating room (OR) can be compensated by collecting precise information on the nonlinear local error in the EMTS by using the OTS for setting up a calibration look-up table. After calibration of the EMTS and registration of the sensor systems in the OR we have found the average euclidean deviation in position readings between the dc tracker and the OTS reduced from 2.9+/-1.0 mm to 2.1+/-0.8 mm within a half-sphere of 530-mm radius around the magnetic field emitter. Furthermore we have found the calibration to be stable after re-registration of the sensors under varying conditions such as different heights of the OR table and varying positions of the OR equipment over a longer time interval. These results encourage the further development of a hybrid magnetooptical tracker for computer-aided surgery where the electromagnetic tracker acts as an auxiliary source of position information for the optical system. Strategies for enhancing the reliability of the proposed hybrid magnetooptic tracker by detecting artifacts induced by mobile ferromagnetic objects such as surgical tools are discussed.

Reconstruction of the maxilla with a double musculoperiosteal flap in connection with a composite calvarial bone graft.

A new technique is shown for a one-stage reconstruction of the mucosa of the floors of the nose and maxillary sinus, the bone structures of the maxilla and the hard palate, as well as the mucosal layers of the hard and soft palates and vestibulum. To accomplish this coverage, a vascularized calvarial bone graft with temporal muscle from one side is combined with a vascularized temporal muscle flap from the other side to achieve a three-layer "sandwich" plasty. The advantage of this procedure is reconstruction of the complete maxillary defect with the possibility of denture rehabilitation and the avoidance of oronasal fenestration. Besides the possible complication of insufficient vascularization of the bone and muscle grafts, the donor defect in the calvarial bone and the missing muscle for mastication are to be considered.

Experimental and clinical results of new advances in the treatment of facial trauma.

Theoretical considerations and photoelastic and mechanical experiments showed us the progression from metal wires to metal plates in different systems. In the midface there is no question about stabilization by miniplate systems. For mandibular fracture treatment, there is a discussion going on at present about the use of stable maxisystems versus less stable minisystems. Our clinical experience of 15 years indicates that there is no further demand for strict stable fixation of mandibular fractures, and we were encouraged to use less stable systems with similar good results, as our follow-up and statistical evaluation showed. To continue the simplification of osteosynthesis methods we are performing experiments with resorbable materials. Early results show fracture healing comparable with that found with plate-and-screw systems. Our clinical experience has shown that there is no longer any question about the ability of stable fracture treatment by means of osteosynthesis. However, there still is the question of how functional such fracture treatment might be.

MRI-based stereolithographic models of the temporomandibular joint: technical innovation.

A new technique of manufacturing dual-colour stereolithographic models of hard and soft tissues of the temporomandibular joint (TMJ) is presented. Sagittal T1/PD weighted magnetic resonance (MR) images of joints with and without disc displacement were obtained in the closed and open mouth positions. Individual interactive contour identification of bony structures and the articular disc followed by binary interpolation provided the data for the generation of acrylic TMJ models. Three dimensional in vivo visualization of the articular disc in relation to bony structures in the closed and open mouth positions allows a new perception of normal and pathological TMJ anatomy.

Lactosorb panel and screws for repair of large orbital floor defects.

In a series of five patients with extensive fractures of the orbital floor, we used a biodegradable sheet for bridging of the bony defects. To achieve optimal support of the orbital contents in their anatomically correct position, we fixed the sheet with at least two resorbable screws to the infraorbital rim. This new technique appears to be superior to conventional methods because it offers reproducible results without the need for secondary interventions.