Biomedical subjects

Christian Schopper

Publications and source records attributed to Christian Schopper.

13 recordsLinked to original sources

PubMed2006

[Neurotoxicity related to lithium-risperidon combination treatment in a patient with schizoaffective disorder].

OBJECTIVE: The case of a schizoaffective patient with a neurotoxic encephalopathy related to lithium-risperidon combination treatment is explored. METHOD: A case report and the relevant theoretical and clinical deliberations are described. CONCLUSIONS: Neurotoxicity related to lithium-risperidon combination treatment is the result of an interaction of different ethiopathogenetic mechanisms. The EEG is the most important diagnostic parameter.

Antimanic Agents↗

PubMed2006

Bone morphogenetic proteins 5 and 6 stimulate osteoclast generation.

Bone regeneration is required for fracture-healing, and different procedures have been used to promote osteogenesis. Recently, BMP-2 has been shown to induce bone formation in vivo and has been tested in clinical trials. A recent in vitro study evaluated the osteogenic activity of 14 BMPs on osteoblastic progenitor cells with an osteogenic hierarchical model in which BMP-2 and BMP-6 may play an important role in inducing osteoblast differentiation. Although the relative osteoinductive activity of each BMP is important, bone regeneration is a process consisting of bone formation and bone resorption. Therefore, it remains unclear which effects BMP-5 and -6 have on the generation of osteoclasts and by which mechanism osteoclastogenesis is stimulated. To compare osteoclastic potency of each BMP, primary murine bone marrow cells were treated with human recombinant BMP-2, BMP-5, or BMP-6 and 1,25-(OH)2 vitamin D3 and stained for the TRAP enzyme. Osteogenic activity of BMP-5 was determined by measuring induction of ALP-activity and proliferation after incubation with primary murine osteoblasts. For elucidating the molecular mechanism, primary bone marrow cells with various concentrations of OPG were added to the TRAP assay and mRNA levels of RANKL and OPG were measured after stimulation with BMP-5. The presented data show that BMP-5 and BMP-6, unlike BMP-2, enhanced the formation of murine TRAP+/MNCs in a biphasic curve. BMP-5 and -6 were less potent in stimulating osteoclastogenesis compared to BMP-2. Concerning the effects of BMP-5 on osteoblasts, there was a dose-dependent increase of ALP activity and proliferation up to a maximum dose of 300 ng/mL. At the mRNA level, BMP-5 increased the RANKL/OPG ratio. In conclusion, this study demonstrates that in contrast to BMP-2, BMP-5 and -6 influences the generation of osteoclasts in a biphasic mode. Both proteins might be very important regulators of bone homeostasis, and therefore, potent candidates for future treatment strategies of bone regeneration.

Acid Phosphatase↗

PubMed2005

HA/TCP compounding of a porous CaP biomaterial improves bone formation and scaffold degradation--a long-term histological study.

In the present study, two biphasic calcium phosphate biomaterials (BCP) with HA/TCP ratios of 50/50 and 30/70 were obtained from a pure HA biomaterial. The biomaterials which showed the same three-dimensional geometry were implanted into corticocancellous costal defects of sheep. In the specimens of all three biomaterials, abundant bone formation, mineral dissolution from the biomaterial scaffolds, and active cellular resorption of the scaffolds was present after 6 and 12 months. Backscattered electron microscopy showed bone invasion into the pores of the scaffolds and micromechanical interlocking at the bone/biomaterial interface without intervening soft tissue. The pattern of bone formation and scaffold resorption was different for cortical and cancellous bone. No time-based effect, however, was observed. Overall, the BCP biomaterials had formed significantly more bone than the HA biomaterial. Also, scaffold resorption, which was followed by a replacement with newly formed bone, was significantly higher in the BCP biomaterials. Although no significant differences were observed between both BCP biomaterials, the present study had confirmed the assumption that HA/TCP compounding was suitable to improve bone formation and scaffold resorption in the investigated biomaterials and at the same time maintain the osteoconductive properties of the scaffolds.

Absorbable Implants↗

PubMed2005

The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheep.

The present study investigated the hypothesis that hydroxyapatite (HA), tricalcium phosphate (TCP), and a HA-gel coated on endosseous titanium (Ti) implants by spark discharging (SD) and dip coating would achieve predictable osseointegration without evident bioresorption of the coatings on the long term. A costal sheep model was used for the implantation of the HA/SD, HA/TCP/SD, and HA-gel/SD specimens, which were retrieved 6 and 12 months following implantation. HA and Ti coatings on implants obtained by conventional plasma spraying (HA/PS, Ti/PS) were used as controls. Microscopy showed that osseointegration was achieved from all types of implants. No evidence for bioresorption of the HA/SD, HA/TCP/SD, and HA-gel/SD coatings was present but cohesive failure with disruption of the coating/implant interface was seen. A statistical analysis of the histomorphometrical data showed no time-dependent effect, however. HA/PS coatings achieved significantly higher bone-implant contact (BIC) percentages of the total implant surface (toBIC) than the other types of coatings (P=0.01). If the BIC percentages were traced separately for implant portions placed into cortical and cancellous bone (coBIC and caBIC, respectively), detailed analysis showed that the caBIC values of HA-gel/SD and HA/PS coatings were significantly higher than that of the other types of coatings (P=0.01). CaBIC values were highly correlated with toBIC values (P<0.001). The present study showed that the preparation techniques used produced thin, dense, and unresorbable coatings that achieved osseointegration. Compared with the control coatings, however, only HA-gel/SD coating can be recommended from the investigated preparation techniques for a future clinical use if a better coating cohesion is achieved.

Animals↗

PubMed2004

Rehabilitation of the severely atrophied maxilla by horseshoe Le Fort I osteotomy (HLFO).

OBJECTIVE: The purpose of this study was to determine the long-term outcome of the horseshoe Le Fort I osteotomy (HLFO) as a preprosthetic operation technique for implant insertion in the extremely atrophied maxilla. STUDY DESIGN: 36 patients (8 male, 28 female, average age 57.6 years) underwent HLFO combined with iliac crest bone grafting. They were divided into 2 groups: group A with 12 patients who simultaneously received 100 implants; group B with 24 patients where 176 implants were inserted in 18 patients in a second-stage procedure. Clinical and radiographic outcome with regard to implant osseointegration, alveolar bone height in the canine and molar regions, peri-implant bone loss and satisfaction of patients (esthetics, masticatory function, overall treatment) were investigated in all cases. RESULTS: The overall 2-year failure-free fraction of implants was 95.5%; the 5-year failure-free fraction was 89.3%. In the 1-step group the 2-year and 5-year failure-free fractions were 95.9% and 86.9%, respectively, in the 2-step group 95.0% and 91.3% (log rank test P=.57). A total of 27 implants were lost during the entire follow-up: 14 in 6 patients of the 1-stage and 13 in 9 patients of the 2-stage group. The mean loss of alveolar bone after augmentation in the canine and molar regions was almost equal in both groups (overall means for the 2 regions 3.67 +/- 2.77 and 4.42 +/- 2.72 mm, respectively). The relationship between the jaws and thereby the esthetic profile could be improved in all cases. All patients were satisfied with the dental rehabilitation and the achieved new esthetic appearance. CONCLUSIONS: HLFO combined with iliac bone grafting is a feasible preprosthetic technique prior to implant insertion in cases of severe atrophy of the maxillary alveolar ridge, leading to satisfying implant survival and rehabilitation of function.

Adult↗

PubMed2004

Histologic findings at augmented bone areas supplied with two different bone substitute materials combined with sinus floor lifting. Report of one case.

This case report is focused on the histologic findings of bone tissue supplied with two different hydroxyapatites (HAs) used for maxillary sinus floor grafting in the same patient after various healing intervals. An insufficient unilateral sinus floor grafting with Bio-Oss biomaterial was followed by an additional grafting procedure with Algipore biomaterial performed 4 years later. Bone samples obtained during second-stage dental implantation contained the interesting combination of Bio-Oss, a bovine anorganic bone substitute, and Algipore, a porous algae-derived HA, in close vicinity, yet after different healing periods. Light microscopy exhibited satisfactory osseointegration of both grafting materials. However, Bio-Oss biomaterial showed no evidence of substantial remodeling after a healing period of 4.5 years. On the other hand, Algipore particles demonstrated signs of remodeling by being locally resorbed and partially replaced with newly formed bone already within 6 months.

Aged↗

PubMed2004

[Guided bone regeneration beneath titanium foils].

The aim of this study was to examine the clinical and histological bony healing process beneath titanium foils used for guided tissue regeneration as well as of the Frios Algipore graft which was applied with autologous bone. 66 sinus floor elevations were carried out and examined over a period of three years and eight months. A success rate of 64% was recorded with foil incorporation. Complications occurred in form of primary and secondary disturbances in the healing process caused by exposure of the foil. 12 of the 66 foils had to be removed early. In all but one case, the augmented bone material was macroscopically well integrated despite the loss of the foil. Primary stability of the inserted dental implants into the ossified augmented site after operations of the sinus maxillaris was reached in all cases with absence of post-operative complications, and in 94% when there was postoperative exposure of the membrane. Histologically, a thin layer of connective tissue poor in cells but rich in collagen fibers appeared underneath the titanium foil. This was followed by newly-formed bony tissue transforming into osseous lamella parallel to the membrane underneath the new periost. In 65 out of 66 cases a sufficient amount of stable bone was built up locally suggesting good bio-compatibility and barrier function. Further, the foil also provided mechanical rest and supporting function for the space underneath. However, the occurrence of healing complications in 36% of the cases showed a need to improve on the titanium foils.

Bone Regeneration↗

PubMed2003

The fluorohydroxyapatite (FHA) FRIOS Algipore is a suitable biomaterial for the reconstruction of severely atrophic human maxillae.

Grafting of the maxillary sinus is an established treatment modality to provide sufficient bone for the fixation of dental implants. We stated the hypothesis that the porous fluorohydroxyapatitic (FHA) biomaterial FRIOS Algipore could be used as a suitable biomaterial for sinus grafting in severely atrophic maxillae. To investigate the accuracy of our hypothesis, 69 trephine specimens from 26 patients who received maxillary sinus grafting with FRIOS Algipore were retrieved during the installation of dental implants. The specimens were processed undecalcified and subjected to histomorphological and histomorphometrical examination. After a mean healing time of 7 months, 23.0% (+/-8.3) new bone had formed around the implanted particles. Bone formation was also evident within the pores of the particles. Statistical analysis indicated that bone formation originated from the sinus floor. Particles provided scaffolding for the promotion of newly formed bone towards apical sinus portions. Mineral dissolution from the walls of the pores was observed prior to and during bone apposition. Thereafter, portions of the particles were resorbed during bone remodeling and replaced by newly formed bone. The present investigation shows that the biomaterial FRIOS Algipore is a suitable biomaterial for sinus grafting of severely atrophic maxillae.

Adult↗

PubMed2003

Neuropsychiatric consequences (atypical psychosis and complex-partial seizures) of ecstasy use: possible evidence for toxicity-vulnerability predictors and implications for preventative and clinical care.

Two case reports of ecstasy abuse and its serious neuropsychiatric complications are presented. The first patient developed a florid paranoid psychosis resembling schizophrenia after repeated long-term recreational ecstasy abuse, and significant alterations with intermittent paroxysmal discharges were found in his electroencephalogram. The second patient showed an atypical paranoid psychosis with Fregoli syndrome and a series of complex-partial epileptic seizures with secondary generalization after a first single ecstasy dose. Both subjects presented considerable vulnerability; the first a minimal brain dysfunction after perinatal asphyxia and a persisting attention deficit/hyperactivity disorder, the second a long-lasting opioid addiction. In vulnerable individuals, dose-independent ecstasy abuse can lead to unpredictable and potentially dangerous neuropsychiatric sequelae which require proper initial assessment and adequate treatment.

Adult↗

PubMed2002

A scanning electron microscopic study on thrombogenicity of intraarterial catheters for chemotherapeutic treatment in head and neck cancer.

BACKGROUND: The purpose of this study was to assess the impact of standard anticoagulation and intermittent catheter irrigation on clot formation on intraarterial chemotherapeutical catheters. METHODS: Sixteen nonheparinized catheters were placed in the carotid vessels of 10 patients. Ten catheters were perfused with chemotherapeutic drugs; six catheters were not perfused. Patients received LMWH anticoagulation; catheters were irrigated with boluses of heparinized saline daily. Catheters were retrieved for SEM evaluation after a mean intravessel placement interval of 21 days. RESULTS: All samples demonstrated accumulation of thrombotic debris on luminal sides and outsides of catheters. Obliteration was seen in three samples. Detachment of thrombus fragments was present in several specimens. No significant dependence of clot formation on placement interval and chemotherapeutic perfusion was calculated. CONCLUSIONS: Standard anticoagulation was ineffective in clot prevention. Heparinized catheters might potentially reduce the risk of clot formation. A delivery system should be engaged for continuous irrigation of catheters with heparinized saline.

Aged↗

PubMed2002

Evaluation of accuracy of computer-aided intraoperative positioning of endosseous oral implants in the edentulous mandible.

The overall accuracy of a novel surgical computer-aided navigation system for placement of endosseous implants was evaluated. Five dry cadaver mandibles were scanned using high resolution computed tomography (HRCT). The position of four interforaminal dental implants was planned on the computer screen and transferred to the cadaver mandibles using VISIT, a surgical navigation software developed at the Vienna General Hospital. The specimens were HRCT-scanned again to compare the position of the implants with the preoperative plan on reformatted slices after matching of the pre- and postoperative data sets using the mutual information technique. The overall accuracy was 0.96 +/- 0.72 mm (range 0.0-3.5 mm). No perforation of the mandibular cortex or damage to the mandibular canal occurred. We conclude that computer-aided implant surgery can reach a level of accuracy where further clinical developments are feasible.

Cadaver↗

PubMed2002

[In-patient hypnotherapeutic trauma exposure for posttraumatic stress disorder: a case report].

This paper describes the treatment of a patient with the diagnoses of a borderline personality disorder and posttraumatic stress disorder (DSM-IV and ICD-10) within the setting of a psychiatric ward spezializing in depression. For purposes of controlled re-exposure to the patient's trauma, a hypnotherapeutic method was chosen. A significant reduction of symptoms, in particular the intrusions and the hyperarousal, was observed. Of great importance in the successful outcome of this case is the integration of hypnotherapy into a multi-dimensional treatment concept including group therapy, physical therapy and anxiety-reducing self-management therapy. This approach facilitated the development of trust and security in the patient required for the hypnotherapeutic intervention and minimized the splitting tendencies specific to borderline patients. Further discussion is centered on the difficulties arising in the context of an emergency ward setting with its high intensity atmosphere encompassing the danger of retraumatization of this special group of patients. Finally several aspects of the clinical implications of this method are addressed.

Adolescent↗

PubMed2002

Fixation of mandibular fractures with biodegradable plates and screws.

OBJECTIVE: Little data exist regarding the use of biodegradable plates and screws for the internal fixation of human mandibular fractures. The purpose of this study was to evaluate the stability of biodegradable, self-reinforced poly-L-lactide plates and screws for the internal fixation of fractures of the human mandible. STUDY DESIGN: Twenty-two individuals (14 male, 8 female; average age, 26.3 years) with a variety of fracture patterns of the mandible underwent management with a biodegradable fixation system. After surgery, maxillomandibular fixation was applied in 3 cases. Images (panoramic radiograph, computed tomographic scan) were taken immediately after surgery and at the 4-week, 8-week, 12-week, and 24-week intervals. The follow-up period averaged 49.1 weeks (range, 22 to 78 weeks). RESULTS: Mucosal dehiscences over the resorbable devices were present in 2 patients. In 1 of these 2 cases, the material had to be replaced with titanium plates. Mucosal healing and consolidation of the fracture were normal in all other patients. CONCLUSION: Self-reinforced biodegradable osteosynthesis materials provide a reliable and sufficient alternative to conventional titanium plate systems.

Absorbable Implants↗