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Biomedical subjects

M Rudert

Publications and source records attributed to M Rudert.

32 records · Page 2Linked to original sources
PubMed1996

Techniques of cartilage growth enhancement: a review of the literature.

This review attempts to present an overview of the literature pertaining to the techniques of cartilage growth enhancement. Only cartilage has an incomplete capacity for self-repair, especially of superficial defects. Full-thickness defects involving the subchondral bone can be repaired with the use of pluripotent progenitor cells from bone marrow or from transplanted perichondreum or periosteum. Bone-cartilage autografts and allografts transplanted into the cartilage defect heal primarily, but they loose their long-term biomechanical qualities because of transformation into fibrous cartilage. Cultivated human chondrocyte autografts may make cartilage healing possible in the future.

Animals↗
PubMed1995

Arterial blood supply of the infrapatellar fat pad. Anatomy and clinical consequences.

The arterial blood supply to the infrapatellar fat pad (Hoffa's fat pad) was investigated in 12 knee joints of human cadavers. The infrapatellar fat pad is supplied by an anastomotic network which displays some striking topographic features. Its vascular blood supply protects it against necrosis, when either reconstructive operations are carried out or extensive surgical exposures of the knee are done. The blood supply to the center of the fat pad is limited. This is of practical importance for the choice of arthroscopic portals. In addition, arthroscopically verified sources of bleeding are described in 57 patients with hemarthrosis without clinically detectable instability. Rupture of the infrapatellar synovial fold can be a cause of posttraumatic hemarthrosis in rare cases. Arteries irregularly found within the fold contribute to the blood supply of the anterior aspect of the synovial membrane covering the cruciate ligaments.

Adipose Tissue↗
PubMed1995

[Gorham-Stout massive ostelysis. A case report].

One case of massive osteolysis Gorham-Stout is presented. Idiopathic osteolysis is a rare disease. The coincidental radiological diagnosis following minor trauma or a few months' history of mild pain involving joints is characteristic. The disease process has a sudden onset. Bones undergo partial or complete resorption, which may spread across joints to contiguous bones. The osteolytic process eventually ceases spontaneously, but generally not before severe deformation and destruction of bone has occurred. Usually radiotherapy is not successful and is followed by local resection of the osteolytic process. Based on our presented case, we suggest early operative treatment to prevent severe damage.

Arthrodesis↗
PubMed1993

Forces involved in length changes of cochlear outer hair cells.

Motion or force generation of outer hair cells may contribute to active modulation of cochlear mechanics. In order to determine the force involved in length changes of outer hair cells, a new in vitro method was used. In the first series of experiments, apical and basolateral extracellular spaces of outer hair cells of the guinea-pig cochlea were separated. Changes of the voltage between the two extracellular spaces induced reversible, proportional changes of the cell length of 4.4 nm/mV if the cell had a length of 80 microns. In the second series of experiments, cell elongations in response to negative pressure applied to the basal end of the cells were measured and corrected for frictional effects. From these data, the compliance of the longitudinal axis of the hair cells was calculated. It was 220 +/- 130 m/N (n = 25) and 240 +/- 170 m/N (n = 24) for cells of the third and fourth cochlear turns, respectively, if the water permeability of the cell membrane was neglected. If the water permeability was taken into account, the compliance was probably around 500 m/N [corrected]. Thus, a mechanism that changes the cell length by 1 microm must generate a static force of at least around 2 nN in an outer hair cell of the organ of Corti [corrected]. Electromotility of outer hair cells, induced by changes of the electrical potential difference across the outer hair cell, is a mechanism that generates this force.

Animals↗
PubMed1993

Detection of lymph and blood vessels in the human intervertebral disc by histochemical and immunohistochemical methods.

Twenty-four intervertebral discs from the lumbar region of postmortem human subjects were investigated by immunohistochemical and histochemical methods to evaluate the pattern of blood and lymph vessels of the discus intervertebralis and surrounding tissue at different ages. Antibodies against the basement membrane component laminin, and the lectin Ulex europaeus agglutinin as a marker for L-fucose in endothelial cells, were used to make the blood vessels visible. The 5'-nucleotidase activity in lymph endothelium served as a marker for lymphatic vessels. The dorsolateral parts of the connective tissue adjacent to the discus intervertebralis were well vascularized in all age groups examined. Vessels in the outer anulus fibrosus were detected in young individuals up to 20 years of age. Vascular canals, i.e. blood vessels in the cartilage end plate, were seen up to 7 years of age. Lymph capillaries are first described here penetrating the disc and peridiscal tissue and accompanying most of the small blood vessels into the areas specified.

5'-Nucleotidase↗
PubMed1993

Lymph and blood supply of the human intervertebral disc. Cadaver study of correlations to discitis.

Immunohistochemical (antibodies against laminin) and histochemical methods (Ulex europaeus lectin, 5'-nucleotidase activity) were used to describe the vascular pattern of human intervertebral discs and the surrounding tissue at different ages. Blood and lymph vessels were found in the connective tissue outside the annulus in all age groups. In the annulus blood vessels and lymphatics were detected up to 20 years of age, in the cartilage end-plate blood vessels appeared up to 7 years of age (cartilage canals). In the nucleus pulposus neither blood nor lymph vessels could be seen at any age. The occurrence of blood and lymph vessels in growing intervertebral discs help us to understand childhood discitis without simultaneous affection of the vertebral body.

Adolescent↗
PubMed1992

Stiffness, compliance, elasticity and force generation of outer hair cells.

Isolated outer hair cells (OHCs) were partially sucked into especially designed cell capillaries allowing an experimental reconstitution of the cells' electroanatomy. The experimental approach separated the apical from the basolateral parts of the cells thus forming an artificial scala media and scala tympani. Resistance between both was 121 +/- 42 M omega. A sequence of negative and positive pressures was applied to the basal cell pole allowing "pulling" or "pushing" of the sensory cell investigated. The resulting length changes together with the known pressures allowed the estimation of an actual longitudinal compliance of 354 +/- 35 m/N. Following "pulling" OHCs tended to resume their initial shape after the force had ceased to be effective indicating elastic distortions. The calculated elasticity modulus of OHCs amounted to 6.1 +/- 3.4 kN/m2. From this data an actual longitudinal whole cell stiffness of OHCs of 3 x 10(-3) N/m was calculated. Ultrasound scanning of immobilized OHCs identified the cuticular plate (CP) and a central core between CP and basal cell pole as structures contributing to the cells' acoustic stiffness. Changes of the potential differences between the artificial scala media and scala tympani resulted in active length changes following the command voltage with a slope of delta 1/(1 x U) = 0.055 V-1. Assuming the validity of Hooke's law, the force generation associated with the active length changes can be calculated since the compliance is known.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Valgus tibial head reconstruction, monocondylar sled prosthesis or bicondylar gliding surface replacement in therapy of medial gonarthrosis--a cost analysis].

AIM: Three to a certain extent competing methods for the treatment of unicompartmental osteoarthritis of the knee are compared regarding the costs they cause. These methods comprise the high tibial valgus osteotomy (HTO), the unicompartmental knee arthroplasty (UKA), and the total knee arthroplasty (TKA). METHODS: We compared the in-patient costs and out-patient costs of 20 patients (drawn by lot) in each group who received one of the above-named operative methods at our hospital between 1988 and 1993. The results were extrapolated according to the expected survival rate of the applied method. RESULTS: The average total costs of patients who received a HTO were 9.487,-; for the unicompartmental arthroplasty the average cost were 11.687,-; the implantation of a TKA resulted in average costs of 16.940,-. All operative procedures exceeded a particular global amount, the socalled "Fallpauschale". CONCLUSION: Regarding the total costs that arise for the operative treatment of the degenerative arthritis of the knee, the HTO (with or without hardware removal) proves to be the cheapest of the applied methods. Projecting the results on the survival rate of each treatment method, no statistically significant differences could be recognized between the three operative procedures.

Adult↗
PubMedDate not supplied

[Characterisation of human meniscus cells].

AIM: The meniscus of the human knee joint has an important function for the shock absorption, stability and power transmission from the upper to the lower leg. After meniscus injury often a partial or complete resection is necessary. Only injuries in the outer third may heal spontaneously or upon primary suture due to the vascularisation in these segments. After partial or total meniscectomy osteoarthritis of the knee joint is common in a large number of patients. The goal of our investigations was to establish meniscus cell cultures and to characterise the fibrochondrocytes (meniscus cells) in vitro. METHODS: We examined the expression of different growth factors, cytokines and proteins in human menisci from surgical preparations using immunohistochemistry and RT-PCR analysis. RESULTS: Human meniscus cells express the collagens I , II, III, and VI, the matrix metalloproteinases-1, -2, -3, -8, and -13, BMP-2, and -4, TGFbeta1, VEGF, IGF-I, and -II, FGF-2, endostatin, iNOS, vimentin, TIMP-1, and -2, aggrecan, IL-1beta, IL-6, and IL-18. Staining with the monoclonal antibody AS.02 in all examined cells confirmed their mesenchymal origin. CONCLUSION: New strategies for the treatment of meniscus damage can be derived from these results and further advances for the tissue engineering of meniscus tissue can be obtained.

Aged↗
PubMedDate not supplied

[Expression analysis of different collagens and cytokines in cartilage cells derived from arthrotic hip and knee joints].

AIM: Osteoarthritis (OA) is characterized by an irreversible destruction of articular cartilage. This is associated with a multiplicity of factors, causing an increased catabolic metabolism in cartilage. However, the prevalence of the OA is very variable in different joints. Therefore , we conducted a comparative analysis of chondrocytes derived from knee and hip joints with respect to their expression of inflammatory factors, such as IL-1beta, IL-1beta-receptorantagonist, iNOS, components of cartilage matrix (collagen I, II, and VI) as well as vimentin. METHODS: Different cytokines and proteins were detected by immune-histochemical staining of cartilage samples ex vivo. Further, chondrocytes were isolated from OA knee and hip joints, expanded in vitro and gene expression patterns were investigated by quantitative RT-PCR. RESULTS: Chondrocytes from knee and hip joints of OA patients express collagenes I, II and VI, IL-1beta and IL-1beta-RA, iNOS as well as Vimentin. A significant difference in gene expression patterns was not found in chondrocytes from the hip joints versus the knee joint ex vivo or in primary culture cells in vitro. However, in vitro the expression of type I collagen exceeded the expression of type II collagen. The IL-1beta-expression was high ex vivo, remained low during primary culture but was significantly elevated after primary culture in hip chondrocytes. CONCLUSION: Osteoarthritic gene expression patterns in cells derived from hip or knee joints ex vivo and in primary culture were not significantly different. We conclude that the rather frequent occurrence of OA in these joints in comparison to the ankle joint may be associated with a close physiological relation of cells in these joints. However, future studies which will include ankle cartilage must be investigated in further detail.

Aged↗
PubMedDate not supplied

[Postoperative autologous transfusion from blood drainage after total hip joint arthroplasty--how much value is really there?].

AIM: Are autologous blood transfusions sufficient or do we need the transfusion of unwashed or washed wound drainage blood in total hip arthroplasty? METHOD: 253 patients undergoing total hip arthroplasty were retrospectively randomized to autologous blood transfusion or transfusion of unwashed wound drainage. We compared the haemoglobin and haematocrit levels as well as the rate of complications. RESULTS: Postoperative blood salvage and reinfusion after total hip joint arthroplasty didn't show any advantages. In 10 % we saw complications after transfusion of unwashed wound drainage. CONCLUSION: We do not recommend the transfusion of wound drainage.

Arthroplasty, Replacement, Hip↗
PubMedDate not supplied

[Results of vacuum sealing therapy in joint infections].

AIM: At present the vacuum sealing technique is acknowledged as a therapy for acute and chronic wounds. An acceleration of the healing process, due to the vacuum suction with occlusive wound dressing, leads to the shortening of a cost-effective medical treatment. This can be applied to wound treatment and infections of soft tissues, but even today there is only sparse information in this context about joint infections. METHOD: The results of therapy with the vacuum sealing technique in 68 patients with infections of the joints of an extremity or the trunk were analysed in a retrospective study without a control group. The importance of several patient-related factors for the medical treatment have been analysed. RESULTS: An adequate treatment of joint infections can be achieved even in the presence of endoprostheses or osteosynthetic material. The following factors have been found to be of significance for a prolonged medical treatment: diabetes mellitus (p=0.0052), obesity (BMI>25) (p=0.0458) and a preceding trauma (p=0.0457). CONCLUSION: The results confirm the value of the vacuum sealing technique following surgical debridement in combination with resistance tested antibiotic treatment, as a sufficient therapy for joint infections, even in patients with an endoprosthesis. This procedure leads to a safe treatment of the joint infection, combined with a good function of the treated joint, good patient comfort and a short duration of the therapy.

Abscess↗
PubMedDate not supplied

[Treatment of fibular capsular ligament rupture. A multicenter study].

The treatment of lateral ankle ligament tears has been by conservative and by operative means. 483 patients treated by a number of orthopaedic surgeons, general surgeons and trauma surgeons in Germany over a 2 1/2 year period were questioned one year after the injury. Treatment had been conservatively in 325 patients (tape bandage, elastic bandage, plaster cast, ankle brace, Aircast brace, others) and operatively in 158 patients (primary ligament repair, ligament reconstruction). A 100 point subjective ankle score was used for the 420 patients who responded. The mean score was 90.5 points. The average score of all patients undergoing surgery was 88.2 points, the mean score of all conservatively treated patients was 91.7 points. However, instability on stress radiographs after the injury was less in the conservative group. There was no clear correlation between the initial radiographic instability and the follow-up result. Young patients did better than older patients. The authors recommend conservative, early functional treatment for lateral ankle ligament tears.

Adolescent↗