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Biomedical subjects

S Kessler

Publications and source records attributed to S Kessler.

At least 19 recordsLinked to original sources
PubMed2006

[Trauma of the spine and intervertebral disk. A challenge for the expert in compensation claims after sustained "trifle trauma"].

In the literature, the association between chronic pain syndromes of the spine and sustained "trifle trauma" is a matter of controversy. "Trifle trauma" is identified as a contusion, compression and/or sprain without a definite, acute imaging sign of injury to the bone, the disk or the ligaments of the spine. Most of the time, striking isolated changes to the intervertebral disks are interpreted as preexisting without relevance to an acute injury. However, complex chronic pain syndromes causing permanent and significant functional limitations in daily life and work may occur. Besides the diagnostic and therapeutic challenge for the treating physician, the expert confronted with compensation claims very often has to answer questions as to whether "trifle trauma" of the spine may lead to significant and permanent functional limitations or loss with chronic pain syndromes, and what the importance of possible isolated changes in intervertebral disks is. The data from literature dealing with this topic is contradictory and deficient. In this article, we critically examine the causality between "trifle trauma" to the spine and possible permanent chronic complaints based on currently available data from the literature in order to support the process of decision making in questions of litigation and controversial compensation claims.

Back Pain↗
PubMed2006

[Preoperative imaging of Charcot neuroarthropathy: Does the additional application of (18)F-FDG-PET make sense?].

UNLABELLED: With about 4 million diabetics in germany and presumed inclination over the following years the treatment of diabetic complications like diabetic foot will become an even more important point. The management of Charcot's foot has undergone fundamental change in the last few years. Formerly, treatment was almost exclusively limited to non surgical measures; since the late 1990's, however, current practice has shifted to early, stage-appropriate surgical therapy. The aim of the present prospective study was to investigate the value of positron emission tomography (PET) in the pre-operative work-up of Charcot's foot. PET were compared to magnetic resonance tomography (MRI). PATIENTS, METHODS: MRI and PET imaging were used as part of the preoperative work-up in 18 patients with Type II diabetes mellitus. The diagnosis of Charcot's foot requiring surgical treatment were made on the basis of clinical and radiologic criteria. RESULTS: Of 46 Charcot's lesions confirmed at surgery, 44 and 35 were detected by means of PET and MRI, respectively. PET can be used in the work-up of patients with metal implants where the MRI does not show adequate findings. PET shows the areas of detritus formation exhibit only moderately increased glucose metabolism and at visual interpretation do not usually impression as typical for acute osteomyelitis. Average SUV values stood at 1.2 (range: 0.5-2.9). CONCLUSIONS: The differentiation between Charcot's lesions and florid osteomyelitis provides the surgeon with important additional information, which is often unavailable from MRI. Because of this important additional data, PET could be considered preferable to morphologic imaging (CT, projection radiography) in the preoperative work-up of Charcot's foot.

Diabetic Angiopathies↗
PubMed2005

The UV erythema test as a model to investigate the anti-inflammatory potency of topical preparations--reevaluation and optimization of the method.

BACKGROUND: The ultraviolet (UV) erythema test is one of the most frequently used methods to investigate the anti-inflammatory potency of topical dermatological preparations in vivo. METHODS: The following questions were addressed in four separate studies with healthy persons (skin types 2 and 3): (1) the optimal localization was determined by comparing light scales on the back, buttocks and volar forearms; (2) the optimal UV-B dose was determined by comparing the 1-fold, 1.5-fold and 2-fold minimal erythema doses (MEDs); (3) hydrocortisone and prednicarbate were evaluated as positive controls, and a sample size calculation was performed, and (4) betamethasone valerate and pimecrolimus were tested as further positive controls in the optimized study model. RESULTS: The back proved to be the best localization for the UV erythema test. It showed a good correlation between the light scale and the test areas. The 1.5-fold MED was the best irradiation dose. In contrast to prednicarbate and betamethasone valerate, hydrocortisone was a rather weak positive control. However, when the sample size was > or = 40 subjects, significant results were also obtained with hydrocortisone. Pimecrolimus was not effective in the UV erythema test. CONCLUSIONS: The UV erythema test should be performed on the back with at least 40 subjects using the 1.5-fold MED. It may be useful to include a potent corticosteroid, such as prednicarbate or betamethasone valerate, in addition to hydrocortisone. The UV erythema test seems to be suitable only for substances with corticosteroid-like effects, since in this test model the calcineurin inhibitor pimecrolimus was not effective.

Administration, Topical↗
PubMed2004

Bone morphogenetic protein 2 accelerates osteointegration and remodelling of solvent-dehydrated bone substitutes.

INTRODUCTION: lt was the purpose of this study to investigate how bone morphogenetic protein 2 (BMP-2) influences remodelling and the biomechanics of solvent-dehydrated bone in the long run. Furthermore, the early influence of this growth factor on the substitute was investigated. MATERIALS AND METHODS: Using a weight-bearing animal model, solvent-dehydrated bone was implanted in the tibial head of merino sheep ( n=12) after being loaded with BMP-2 (100 microg/100 microl). At 4 weeks ( n=6) and 9 months ( n=6) after surgery, histomorphological, histomorphometrical and biomechanical investigations were performed. RESULTS: At 9 months after implantation of BMP-2-loaded specimens, the bone per tissue volume was high, with levels above those of physiological cancellous bone. The amount of remaining solvent-dehydrated bone was markedly decreased, and in contrast, the amount of newly formed bone was extremely high. The specimen degradation had already occurred within the first 4 weeks after implantation, showing no further impact throughout the 9-month period. Biomechanical investigations at 9 months after implantation demonstrated a yield strength which achieved levels at least equivalent to physiological cancellous bone. BMP-2 showed no significant impact on the biomechanical properties after 4 weeks, compared to specimens prior to implantation. CONCLUSION: BMP-2 predominantly has an impact on the early implant degradation as well as bone formation, which leads to an almost completed bone remodelling of the solvent-dehydrated specimen within the study period of 9 months.

Animals↗
PubMed2003

First carpometacarpal and interphalangeal osteoarthritis of the hand in patients with advanced hip or knee OA. Are there differences in the aetiology?

Differences in the aetiology of osteoarthritis (OA) of the first carpometacarpal joints (CMC-1) and the interphalangeal joints (IP) have been reported. It was the purpose of this investigation to evaluate whether isolated OA of the first carpometacarpal joints and the interphalangeal joints differs in its aetiology, considering potential risk factors such as age, gender, body mass index, occupational history, OA in the hip or knee joints, hypertension and diabetes in patients with advanced hip or knee OA. Included in this investigation were 639 patients scheduled for either hip or knee replacement because of advanced OA. As well as a standardised interview and clinical examination, bilateral radiographs of both hands were obtained. According to the presence or absence of radiographic OA, participants were categorised as having CMC-1 OA (= 1 joint) or IP OA (= 2 joints), either isolated or in combination. Odds ratios (OR) and their 95% confidence intervals (CI) for potential determinants of OA were estimated using multivariable logistic regression. Of the total number of patients, 184 had CMC-1 OA and 424 IP OA. Patients with CMC-1 OA were more likely to be female (77.2%), and to have knee OA (62.5%) and hypertension (63.0%), than patients without CMC-1 OA. No differences between CMC-1 OA and IP OA were observed for the role of age, body mass index and diabetes. Age was associated with both CMC and IP OA. Female gender was independently associated with CMC-1 OA (OR=1.79; 95% CI: 1.16-2.74) but not with IP OA. Our data suggest a possible impact of age and female gender on the aetiology of CMC-1 OA and of age on IP-OA, at least in patients with advanced hip or knee OA.

Age Distribution↗
PubMed2003

Revision total hip arthroplasty: the influence of gender and age on the perioperative complication rate.

PURPOSE OF THE STUDY: Aim of this study was to report the incidence of complications in a consecutive series of revision total hip arthroplasties (THA). Gender and age as a risk factor for the occurrence of perioperative complications in patients undergoing revision THA were analyzed specifically. MATERIAL: All consecutive revision THA (n = 169) for aseptic loosening, which were performed between 1998 and 2002 were evaluated. Our study population had a mean age of 71.7 years and consisted of 65.7% women and 34.3% men. Complete exchange of the primary implant was performed in 49.7% (84/169). The cup was replaced in 66 cases (39.1%) the stem only in 11.2% of patients (19/169). METHODS: Retrospective analysis was performed assessing the influence of gender and age on the complication rate by multiple regression models, estimating odds ratios (OR) and their 95% confidence intervals (CI). RESULTS: Comparable complication rates to those reported in the literature were found. Overall incidence of complications was 29.6% with a fracture rate of 6.5%, dislocation rate of 8.3%, nerve palsy rate of 4.7% and occurrence of thromboembolism in 1.8% of the reported cases. Mortality rate during the observed period was low (0.6%). We were not able to provide statistical evidence for the impact of gender and age on the complication rate. DISCUSSION: A comparable complication rate following revision THA to those reported in the literature was found in our study sample. Corresponding to other authors a higher risk of nerve palsy and thromboembolism among women was assessed. The observed correlation of fracture rates and female gender might be attributable to osteoporotic bone in postmenopausal women. Dislocation seemed to be more frequent in older patients, which has been described previously as well. Our low mortality rate in revision THA comparable to previous reports might be due to our short observation period. CONCLUSIONS: Revision THA is associated with a higher risk of complications than primary THA. A predictive value of gender and age in regard to the overall complication rate could not be confirmed which should be considered while deciding about the therapeutic strategy confronted with an aseptically loosened THA. To provide statistical evidence of a correlation between gender, fracture and nerve palsy as well as age and dislocation rates greater study populations are required.

Age Factors↗
PubMed2002

Adsorption and release properties of growth factors from biodegradable implants.

The present investigation was performed to study the adsorption behavior of growth factors and their release characteristics from biodegradable implants in an in vitro study. We investigated the stability of growth factors administered on various scaffolds. We used porous tricalcium phosphate ceramics (alpha-TCP), a neutralized glass-ceramics (GB9N), a composite (polylactid/-glycolid/GB9N), and solvent dehydrated human bone as carriers. Block shaped scaffolds (sized: 7 x 7 x 10 mm) were loaded with 5 microg of either bone morphogenetic protein (rxBMP-4), basic fibroblast growth factor (rh-bFGF), or vascular endothelial growth factor (rh-VEGF) solved in 150 microL PBS. The growth factors were labeled with Iodine125 (I-125) for detecting the adsorbed and released amount of growth factors by counting the samples for total I-125 activity. We observed that the adsorption of these growth factors seems to depend on two different parameters: first on the nature of the tested material, and second on the growth factors on their own. The release kinetics of the growth factors from the biodegradable implants can be described as a two phase process-a very rapid release during the first hours by an elution of not adsorbed protein, followed by a specific release, which depends upon the chemical/physical interaction of the material and the growth factor used. Analyzing the eluted proteins on SDS-PAGEs rh-VEGF was degraded into a smaller fragment with a size of around 15 kDa, while rxBMP-4 and rh-bFGF showed a complete degradation into fragments smaller than 3 kDa after more than 3 days. Although this in vitro study suggests that biodegradable implants might be successfully used as carriers for osteogenic growth factors, the different release kinetics as well as the alteration of their molecular structure including loss of biological activity should be considered.

Absorbable Implants↗
PubMed2002

Vascular endothelial growth factor stimulates chemotactic migration of primary human osteoblasts.

Recent studies have indicated a critical role for vascular endothelial growth factor (VEGF) during the process of endochondral ossification, in particular in coupling cartilage resorption with bone formation. Therefore, we studied the chemoattractive and proliferative properties of human VEGF-A on primary human osteoblasts (PHO) and compared these data with the effects of human basic fibroblast growth factor (bFGF) and human bone morphogenetic protein-2 (BMP-2). Furthermore, initial experiments were carried out to characterize VEGF-binding proteins on osteoblastic cells possibly involved in the response. For the first time, to our knowledge, we could demonstrate a chemoattractive effect of VEGF-A, but not VEGF-E, on primary human osteoblasts. The effect of VEGF-A was dose-dependent and did not reach a maximum within the concentration range tested (up to 10 ng/mL). The maximal effect observed was a chemotactic index (CI) of 2 at a concentration of 10 ng/mL. bFGF and BMP-2 exhibited maxima at 1.0 ng/mL with CI values of 2.5 and 2, respectively. In addition to its effect on cell migration, VEGF-A stimulated cell proliferation by up to 70%. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the expression of VEGF receptors VEGFR-1 (Flt-1), VEGFR-2 (Kdr), and VEGFR-3 (Flt-4), as well as neuropilin-1 and -2. An in vitro kinase assay failed to demonstrate activation of VEGFR-2 upon stimulation with either VEGF-E or VEGF-A, consistent with the idea that the effect of VEGF-A on primary human osteoblasts is mediated via VEGFR-1. Taken together, our data establish that human osteoblasts respond to VEGF-A, suggesting a functional role for this growth factor in bone formation and remodeling.

Aged↗
PubMed2002

Histomorphological, histomorphometrical and biomechanical analysis of ceramic bone substitutes in a weight-bearing animal model.

It was the purpose of this investigation to prove the biomechanical properties, the osteoconductive capacity and the degradation rate of alpha tricalcium phosphate (alpha TCP), a neutralized glass ceramics (GB9N) and a composite material (GB9N+copolymers). In a weight-bearing animal model six substitutes each were implanted in the medial tibial head of the right lower leg of adult Merino-sheep in a standardized surgical technique. After nine months the implants were harvested and prepared for histomorphological and histomorphometrical investigations (undecalcified Masson Goldner staining). For additional biomechanical testing of the specimens, non-operated bone blocks from the contralateral tibia as well as native implants served as controls. No significant differences for the maximum fracture load as well as for the yield strength were detected between harvested specimens and bone blocks from the contralateral tibia. However there were marked differences to ceramics that were not implanted. All substitutes showed osteoconduction, leading to a continuous ingrowth of new formed bone. However in the composite material soft tissue could be identified within the scaffold and there were signs of ongoing bone remodeling, nine months after implantation. The bone per tissue volume of alpha-TCP in conjunction to new bone (=percentage of trabecular bone volume plus percentage of residual substitute) was higher than for GB9N and the composite material. Nine months after implantation the percentage of residual alpha-TCP was 48%, it was 32% for GB9N and 28% for the composite. The intention of further studies should be to accelerate the degradation rates of substitutes and to improve biomechanical properties of implants by either modifying the chemical composition or combining materials with agents as, e.g. growth factors.

Journal Article↗
PubMed2002

[Vertebral manifestation of chronic recurrent multifocal osteomyelitis (CRMO)].

Chronic recurrent multifocal osteomyelitis (CRMO) is a systemic osteo-articular disease that is characterized by a sterile, primarily chronic osteomyelitis with various distribution patterns of the individual lesions. In this article, we describe the "axial type" with predominant involvement of the spine, which represents 13 of our 41 CRMO cases of different age groups. The important element of its diagnosis is the typical lympho-plasmacellular spondylitis that can be detected and staged by scintigraphy, MRI and conventional radiography. Potentially affected are all vertebrae from the mid-cervical spine to the sacrum. One or several segments can be involved, sometimes as transient inflammatory edema, sometimes as "migratory spondylitis" or "saltatory spondylitis", but also as chronic sclerosing type with early radiographically detectable manifestation. Vertebral deformity due to compression and total collapse (vertebra plana) are rare. A complicated course with patulous perivertebral edema can lead to concomitant symptomatic inflammatory changes in adjacent regions and organs. In the course of CRMO, spondylodiscitis only develops as secondary destruction following the spondylitis. This can help to differentiate spondyloarthropathies from CRMO that is initially detected as primary lesion in the spine. While CRMO generally has a good prognosis, its radiological differentiation from rheumatologic conditions plays an important role.

Acquired Hyperostosis Syndrome↗
PubMed2001

Developmental changes due to long-distance movement of a homeobox fusion transcript in tomato.

Long-distance movement of RNA through the phloem is known to occur, but the functional importance of these transported RNAs has remained unclear. Grafting experiments with a naturally occurring dominant gain-of-function leaf mutation in tomato were used to demonstrate long-distance movement of mutant messenger RNA (mRNA) into wild-type scions. The stock-specific pattern of mRNA expression was graft transmissible, indicating that the mRNA accumulation pattern is inherent to the transcript and not attributable to the promoter. The translocated mRNA caused changes in leaf morphology of the wild-type scions, suggesting that the translocated RNA is functional.

Artificial Gene Fusion↗
PubMed2001

[Biosurgical methods tested in 10 patients. Maggots into the wound--do they promote healing?].

Between 07.04.1999 and 06.07.1999 we used sterile maggots for the treatment of 10 patients having acute infections as well as chronic wounds. All patients had had unsuccessful treatment for more than six weeks before we started our regime. Patients with acute infections and most diabetics had the best short-term results. In some diabetics, in chronic arterial occlusive disease (stage 4) and in rare cases of chronic infections like steroid associated wounds or thrombangitis obliterans The treatment had no success or there were complications. The etiologically broad range of wounds and our limited experience with biosurgery limit the result of our study. In spite of that we regard biosurgery to be a very promising part of the range of surgical wound treatment.

Animals↗
PubMed2001

Proliferation and differentiation rates of a human osteoblast-like cell line (SaOS-2) in contact with different bone substitute materials.

The aim of our study was to investigate the influence of four bone substitutes on the growth behavior of a human osteoblast-like cell line (SaOS-2) culture: pure alpha tricalcium phosphate (alpha-TCP = BIOBASE), a bioactive glass (bioglass), a neutralized glass-ceramic (GB9N), and solvent dehydrated bone. We established an in vitro cell culture model with three-dimensional scaffolds (cubes of 0.7 x 0.7 x 1.0 cm) of porous bone substitutes to investigate proliferation and differentiation rates of SaOS-2 cells. The cultures were analyzed for individual cell morphology after 5 days of growing using scanning electron microscopy. Fracture preparations of the cubes showed that cells could infiltrate the porous structures, but the cell shapes varied from individual round-shaped cells to wide spread cells and cell clusters, depending on the material. Also, the differentiation of the seeded cells was dissimilar after a 5-day incubation. The specific alkaline phosphatase (ALP) enzyme activity (ALP/DNA) measured in the supernatants of alpha-TCP-grown cells was nine times higher than the lowest activity, as observed by cells incubated on GB9N. Early (Collagen1, ALP) and late marker (osteocalcin, bone sialoprotein) of osteoblastic differentiation were proofed by reverse transcriptase-polymerase chain reaction analysis. Cells grown on bone substitutes and bioglass seem to be less differentiated than alpha-TCP-grown cells, because of noticeably less amounts of osteocalcin and bone sialoprotein. The cultivation on GB9N seems to dedifferentiate the cells, because even the ALP expression was reduced as well. Our results indicate that distinct bone substitutes influence proliferation and differentiation of osteoblastic cells in different manners. These results might influence the selection of an adequate bone substitute for clinical use as well, part from degradative and biomechanical properties.

Bone Substitutes↗
PubMed2001

Solvent dehydrated bone transplants to bridge segmental bone defects: histomorphological and biomechanical investigations in an animal model.

Cancellous bone is routinely used in human surgery to fill skeletal defects. The availabilty of autogenous and allogenous grafts is limited, however. The aim of this in vivo study was therefore to determine the in-growth behaviour and biomechanical properties of solvent dehydrated human bone as an alternative to the use of autografts. In a weight-bearing experimental model, solvent dehydrated bone transplants were implanted subchondrally in the medial proximal tibia of merino sheep. After 9 months, explants as well as controls from the contralateral leg were harvested and prepared for histomorphological, histomorphometrical and biomechanical examination. A smaller, but statistically insignificant difference was found for the yield strength after 9 months for harvested specimens in comparison with untreated controls. Regarding the histomorphological results, we found a homogenous ingrowth of new bone trabeculae throughout the transplants. The degradation of the solvent dehydrated bone was not complete within the study period as shown by persistent bone remodelling. The bone per tissue volume of remaining solvent dehydrated graft particles together with newly formed bone was significantly higher than for controls. Our observation period was not long enough to document complete remodelling, but good osteointegration and reasonable biomechanical properties in this weight-bearing large animal model support the application of solvent dehydrated bone in cancellous defects of clinical relevance.

Animals↗
PubMed2001

Hysterectomy and patterns of osteoarthritis. The Ulm Osteoarthritis Study.

OBJECTIVE: To determine the association between hysterectomy (HE) and patterns of osteoarthritis (OA) METHODS: We performed a large cross-sectional study including 504 female patients admitted for arthroplasty of knee or hip joint. Patients with OA were categorized as having bilateral or generalized OA (GOA) according to the presence of radiographic OA in the contralateral or different finger joints. Odds ratios (OR) and their 95% confidence intervals (CI) for the association between HE and OA patterns were estimated adjusting for potential confounders. RESULTS: Hysterectomy (HE) was reported by 24.9 percent of the patients. Bilateral OA was present in 86.2 percent and GOA was present in 33.3 percent of the patients. HE was not associated with bilateral OA (adjusted OR=0.9; 95% CI: 0.5-1.8) but with a lower prevalence of GOA (adjusted OR=0.6; CI: 0.3-0.99). CONCLUSION: In contrast to earlier studies our results suggest that HE might be a marker for a reduced risk for a generalized pattern of OA.

Age Distribution↗
PubMed2001

Psychological aspects of genetic counseling. XIV. Nondirectiveness and counseling skills.

The difficulties some professionals have in achieving nondirective goals is largely due to the inadequate and ineffective application of basic counseling skills. The "new genetics," with its emphasis on decision-making in association with genetic testing, is among the most demanding forms of personal counseling, the effectiveness of which depends largely on the professional's human experience and counseling abilities. Examples are given showing inadequacies in professional responses to clients in genetic counseling which, in turn, defeat the achievement of a nondirectiveness that is helpful to clients, supports their self-directedness, and leaves them more psychologically prepared for quality decision making. Other models of counseling (e.g., shared decision making) will not fare any better than the nondirective one unless counseling skills of professionals in genetic services are upgraded in a significant way. Professional organizations need to give greater attention to the training and postgraduate supervision of all personnel involved in genetics services.

Decision Making↗