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Biomedical subjects

S Rupp

Publications and source records attributed to S Rupp.

At least 19 recordsLinked to original sources
PubMed2001

[Effect of various suture strength factors on behavior of meniscus sutures in cyclic loading conditions].

The aim of this study was to analyze meniscal sutures under cyclic loading conditions for different suture types (vertical and horizontal mattress sutures) and suture materials (absorbable monofilament sutures: PDS 2-0; PDS-0, and PDS-1 USP). Testing was performed on medial porcine menisci, using a well-established biomechanical testing model with a complete longitudinal tear 3 mm from the periphery of the meniscus. Sixty specimens were used. One suture was tested at a time. During cyclic testing 100 load cycles were applied with a crosshead speed of 50 mm/min. Three different maximum loads (10 N, 20 N, and 40 N) were used. The preload was set at 5 N. After cyclic loading, the specimens were loaded until failure. During cyclic loading, a gap appeared between the two parts of the meniscus, and partial tissue failures were observed at the surface of the meniscus. Gapping was more marked with higher loads and with the weaker suture material (p < 0.001). Using PDS 0 and PDS 1 sutures, less partial tissue failures were observed compared to PDS 2-0 (p < 0.001). The ultimate failure loads after cyclic loading were higher with PDS-0 and PDS-1 sutures. With these suture materials vertical sutures were stronger than horizontal sutures (p < 0.05). Using PDS 2-0 this difference could not be found. These results show that the primary strength of meniscal sutures depends on the suture material. The frequency and the amount of gapping and partial tissue failures, which can be observed under cyclic loading, are less distinct with PDS-0 and PDS-1 compared to PDS 2-0. From a biomechanical point of view, PDS 0 and PDS 1 sutures are recommended for meniscal sutures to guarantee a high primary stability, a small amount of gapping, and few partial tissue failures.

Animals↗
PubMed2001

[Long-term results after excision of a popliteal cyst].

The objective was to evaluate long term results after removal of a popliteal cyst with special focus on recurrence rate and associated intraarticular pathology. Between 1982 and 1995 71 patients (23 women and 48 men between 21 and 75 years of age) underwent removal of a popliteal cyst. An additional arthroscopy of the knee joint was carried out in 51 consecutive patients starting in 1988. The mean follow up was 6.5 years (2 to 15 years), 66 patients (93%) were available. The subjective satisfaction with the outcome was assessed using a visual analogue scale (VAS) graded from 1 (highly satisfied) to 10 (highly dissatisfied). The popliteal region was evaluated by ultrasonography for recurrence of a cyst. During arthroscopy the predominant associated intraarticular pathologic finding was the lesion of the posterior horn of the medial meniscus (75%) and the lesion of the hyaline cartilage (90%). The cyst recurrence rate was 71%. In this subgroup grade III and grade IV chondral lesions were significantly more frequent (p < 0.001). Patients with a recurrence of the popliteal cyst rated the result significantly worse (7.6 +/- 2.3 vs. 3.4 +/- 2.3; p < 0.001). The recurrence rate was relatively high in the long term follow up. It depends strongly on the type of associated intraarticular pathology. Especially grade III and grade IV chondral lesions correlated significantly with recurrence of a popliteal cyst after removal. Therefore, the main goal of surgery should be the successful treatment of associated intraarticular pathologies.

Adult↗
PubMed2001

[Approach to open treatment of osteochondral lesions of the talus].

Arthroscopic techniques still represent the treatment of choice in osteochondral lesions of the talus (OLT). Open techniques may be used as an alternative or may be complementary to arthroscopic treatments. They are especially indicated in cases of large osteochondral lesions, difficult localisations and in cases of recurrent interventions. In addition to the type of treatment for the lesion itself, the choice of an ideal surgical approach is of paramount importance. Indications, operative technique, possible complications and rehabilitation are described in detail for each approach. Anterolateral, anteromedial, posterolateral and posteromedial soft-tissue approaches as well as medial and lateral malleolar osteotomies are discussed. If a distraction is not desired with arthroscopy, posteromedial and posterolateral soft-tissue approaches offer a good alternative for the treatment of posterior OLT. Osteotomy of the (medial) malleolus offers good visualisation of the medial talar dome. With the introduction of new techniques of osteochondral transplantations, the use of this approach is becoming more popular. However, it is an invasive technique and the risk of secondary osteoarthritis after malleolar osteotomy still needs to be determined.

Ankle Injuries↗
PubMed2001

[Biomechanical properties of interference screw implantation in replacement of the anterior cruciate ligament with patellar and hamstring transplants. An experimental study using roentgen stereometry analysis (RSA)].

This experimental roentgen stereometric analysis (RSA) study was performed to measure micromotions between the graft and tunnel under submaximal load in anterior cruciate ligament (ACL) reconstruction. The aim was to evaluate the maximum load at failure, linear stiffness, and slippage of bone-patellar-tendon-bone (BPTB) grafts fixed with interference screws compared to quadrupled hamstring grafts fixed with interference screws. We used 15 porcine tibia specimens for the study. In the BPTB group, the 10 x 25-mm bone plugs were fixed in a tunnel with 10 mm in diameter using a 7 x 25-mm titanium interference screw (n = 5) or a biodegradable screw (n = 5). The five hamstring transplants were folded to a four-stranded graft and armed with a baseball stitch suture. The sutured side was fixed with a 7 x 25-mm biodegradable polylactide screw in an 8-mm tunnel. The tibial bones, tendon grafts, and interference screws were marked with tantalum beads. The grafts were mounted to a custom made load frame and loaded parallel to the axis under RSA control increasing the force in steps of 50 N. Micromotions between bone plug, screw, and tibia were measured with RSA. Accuracy of RSA for the in vitro study was evaluated as 0.05 mm. Hamstring grafts failed at significantly lower maximum loads (492 +/- 30 N) than BPTB grafts (658 +/- 98 N). Linear stiffness of the hamstring graft fixations was eight times lower compared to the BPTB grafts (403 +/- 141 N/mm vs 3500 +/- 1300 N/mm). There was no significant difference between the biodegradable and titanium screws in the BPTB group. Slippage of the graft started at 82 +/- 35 N load in the hamstring group and at 428 +/- 135 N in the BPTB group. Slippage of the graft at 75% of the maximum pull-out strength was measured as 0.36 +/- 0.25 mm in the BPTB and 2.58 +/- 1.08 mm in the hamstring group. The interference screw fixation of a quadrupled hamstring graft showed a lower linear stiffness and an earlier slippage compared to a patellar tendon bone plug. Slippage of the hamstring grafts at submaximal loads may result in fixation failure during rehabilitation.

Animals↗
PubMed2001

Knee laxity after ACL reconstruction with a BPTB graft.

UNLABELLED: The objective of the study was to compare prospectively short-term and mid-term results after ACL reconstruction with special focus on changes in instrumented knee laxity. METHODS: The original study group included prospectively 58 patients who underwent arthroscopically assisted ACL reconstruction with BPTB graft in a two-tunnel technique between 1991 and 1993. Seven patients were lost to follow-up, leaving 51 patients for a first follow-up at 6 months and a second follow-up at 3-6 years (mean 4.3 years). Clinical results were evaluated by means of the Lysholm score and the IKDC score. Laxity was assessed using a KT-1000 arthrometer applying an 89 N anterior load in 20 degrees of flexion. Increased laxity was defined as a 3 mm increase in AP translation between the first and the second follow-up. RESULTS: At mid-term follow-up pivot shift was negative in 86% of cases. IKDC score: normal = 28%, nearly normal = 44%, abnormal = 24%, severely abnormal = 4%. KT-1000: < 3 mm = 68%, 3-5 mm = 24%, > 5 mm = 8%. The mean KT-1000 side-to-side difference was 1.08 (0.17) mm at 6 months and 2.01 (0.29) mm at 3-6 years. The difference was statistically significant (P < 0.005). According to the defined criteria, seven patients had increased laxity at the second follow-up, suggesting a malfunction of the graft due to stretch-out or injury. In this subgroup the mean KT-1000 measurements were 0.86 (0.26) mm at the first follow-up and 5.93 (0.54) mm at the second follow-up. In five of these patients, a malposition of the tunnels was identified as a possible cause. In the remaining group, KT-1000 measurements did not differ significantly between the first and the second follow-up [1.12 (0.20) mm versus 1.37 (0.21) mm]. CONCLUSIONS: Increase in AP laxity occurred in 14% of our cases between the first and the second follow-up. In most of these cases increased laxity was due to inadequate surgical technique, especially malposition of bony tunnels. If tunnel position was correct, there was no evidence for elongation of grafts over time as a general principle.

Adult↗
PubMed2001

Fracture of the proximal tibia six months after Fulkerson osteotomy. A report of two cases.

The Fulkerson osteotomy has proved to be a reliable treatment for subluxation of the patella due to malalignment. Aggressive rehabilitation in the early postoperative period is unwise since the proximal tibia is weakened by the oblique osteotomy. Early weight-bearing and unrestricted activity have caused fractures in a few patients. Even late in the postoperative period the osteotomy may adversely influence the biomechanical properties of the proximal tibia. We describe two athletes who sustained a fracture of the proximal tibia, during recreational activities, six months after a Fulkerson osteotomy. Both had been bearing full weight for about ten weeks without complaint. Bony healing of the osteotomy had been demonstrated on plain radiographs at ten and at 12 weeks. After a Fulkerson osteotomy, jogging and activities which impose considerable impact force should be discouraged for at least nine to 12 months.

Adult↗
PubMed2000

A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics.

In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.

Antibodies, Antinuclear↗
PubMed2000

Evaluation of transarterial embolization for lower gastrointestinal bleeding.

INTRODUCTION: Transcatheter arterial embolization has been used as a therapeutic maneuver for lower gastrointestinal bleeding. The availability of highly selective arteriography has made this procedure safer and warrants re-evaluation. METHODS: A retrospective chart review was done of all patients undergoing arteriography for presumed lower gastrointestinal bleeding at two acute-care community hospitals. Causes of bleeding, clinical outcome, and complications caused by transcatheter arterial embolization were recorded. RESULTS: There were 26 arteriographically identified bleeding sites in the colon and small bowel. The most frequent cause of bleeding was diverticulosis (12 patients), with the diagnosis being arterio venous malformation in two, and one unknown colonic source. Transcatheter arterial embolization was attempted for 17 separate bleeding episodes in 16 patients. Transfusion requirements were an average (+/- standard deviation) of 7 +/- 1.43 units per patient. Transcatheter arterial embolization was successful in stopping bleeding in 14 cases (82 percent). Two patients had surgery after transcatheter arterial embolization: one for colonic necrosis and one for persisting bleeding. There were two more unsuccessful procedures; one had a successful repeated transcatheter arterial embolization, and one stopped spontaneously. One patient rebled during the same hospitalization and was controlled with intra-arterial vasopressin. There were two deaths, both secondary to sepsis unrelated to the transcatheter arterial embolization or the gastrointestinal tract. CONCLUSIONS: Transcatheter arterial embolization is a relatively safe and successful procedure in patients with massive lower gastrointestinal hemorrhage. It is an excellent choice of therapy for patients that are poor candidates for surgery, but its role in other patients remains to be defined.

Aged↗
PubMed2000

[Strategies for interventional revisions in failed anterior cruciate ligament reconstruction].

Anterior cruciate revision reconstruction is gaining more and more importance. Postoperative infection, a painful knee, limited range of motion and instability may make a second operation necessary. Results after revision ACL reconstruction are worse than results after primary ACL reconstruction. Analysis of the causes of failure and a therapeutic concept that is tailored to the individual case are preconditions for a successful reintervention. Revision ACL reconstruction has to be performed by an experienced knee surgeon who masters all the necessary techniques, from arthroscopy to arthrotomy and should be carefully planned.

Anterior Cruciate Ligament↗
PubMed2000

[Donor site problems after anterior cruciate ligament reconstruction with the middle third of the patellar ligament].

In a retrospective study we examined the clinical and sonographic changes after anterior cruciate ligament reconstruction with lig. patellae. 51 patients were evaluated clinically and sonographically after arthroscopically assisted ACL-reconstruction with a bone-patella tendon 3-6 years (mean 4.3 years) postoperatively. Certainly 18 patients (35%) reported about an anterior knee pain, but only 2 patients (4%) complained about pain during activities of daily living and 3 patients (6%) about pain during slight sports activities. Retropatellar crepitations was found in 24 patients (47%) on the operated side and at 11 patients (22%) on the non operated side. Twenty nine patients (57%) complained about a discomfort or pain when kneeling on the operated side. In 13 patients (26%) sonography showed a shortening of the patella ligament by 4 mm or more. Only few patients are strongly limited in their activity by the anterior knee pain. Neither our results nor the literature give evidence, that the tendon defect is the underlying cause of this pain syndrome. However, the number of patients with pain during kneeling on the operated side was relatively high. The semitendinosus gracilis graft should be considered for patients who have to knee during working or recreational activities.

Anterior Cruciate Ligament↗
PubMed2000

[Knee endoprosthesis: aspects of surgical techniques].

The implantation of a condylar knee has remained a challenge for surgeons and the equipment of the hospital. In contrast to total hip arthroplasty, not only is the correct insertion of the implant crucial, but also the treatment of the surrounding soft tissues. Mediolateral soft tissue balance and balance between flexion and extension gaps, as well as centering the patella, have to be done carefully. The soft tissue envelope of the knee joint is thin and prone to necrosis after multiple incisions. Damage to the extension mechanism can make a total joint useless. Tearing the patellar ligament from the tibial tuberosity must therefore be avoided by all means during operation. Precise cutting of the distal femur is only possible if excellent equipment is used by a skillful surgeon. The same is true for orientating saw cuts related to the long leg axes. These tasks can probably be taken over by navigation systems and robots in the future. Because the definite choice of implants has to be made intraoperatively, a complete modular system has to be present in the hospital. Only hospitals that can properly equip their surgeons to manage upcoming soft tissue problems and bony deficiencies should offer treatment to patients requiring condylar knee arthroplasty.

Arthroplasty, Replacement, Knee↗
PubMed2000

Reliability and interobserver variability in radiological patellar height ratios.

This study evaluated the reliability and interobserver variability of five patellar height ratios as measured by two examiners on standard radiographs: Insall-Salvati (IS), modified Insall-Salvati (MIS), Blackburne-Peel (BP), Caton-Deschamps (CD), and Labelle-Laurin (LL). Plain lateral radiographs with a knee flexion angle of 20 degrees for IS, MIS, BP, and CD ratios and 90 degrees for the LL method of 22 knees of 21 patients with varying pathological knee conditions were analyzed. Statistical results revealed a low interobserver variability with high correlation coefficients (0.86 for IS, 0.82 for MIS, 0.86 for BP, 0.92 for CD, and 0.81 for LL; P > 0.3) and low mean interobserver errors. However, regarding the reliability of the radiographic results of the different methods for patella alta, baja, or norma we found varying results in 68% of the patients. In two patients the patellar height was classified as alta, norma, or baja depending on the ratio used. Regarding the definitions of patellar height used by the authors of these methods, we found the lowest number of normal patellae with the IS ratio and no patella alta for the CD ratio. The LL method revealed the highest number of patella alta. The BP ratio showed intermediate results for both patella alta and baja, being the most moderate method. This study showed that there was a good interobserver reliability for the evaluation of patellar height according to the common radiological ratios. However, the high frequency of differing results between the different radiographic ratios showed that patellar height classification as "alta," "norma," or "baja" depends heavily on the chosen index. The differing results were due mainly to the normative patellar height data and to anatomical differences. Based on these findings we recommend a ratio using the articular surface of the patella in relation to the joint line. We recommend the BP method because it revealed the lowest interobserver variability and discriminated best among the groups alta, norma, and baja.

Adolescent↗
PubMed2000

Extracorporal shock wave therapy in patients with tennis elbow and painful heel.

The aim of this study was to evaluate the effect of extracorporal shock wave therapy (ESWT) in tennis elbow and painful heel. Nineteen patients with tennis elbow and 44 patients with painful heel in which conservative treatment had failed underwent ESWT. Both groups received 3000 shock waves of 0.12 mJ/mm2 three times at weekly intervals. After a follow-up of 5 and 6 months respectively, pain measured on a visual analogue scale (VAS) decreased significantly in both groups. The success rate (excellent and good results) was 63% in tennis elbows and 70% in painful heels. ESWT seems to be a useful conservative alternative in the treatment of both conditions.

Adult↗
PubMed2000

The TEA/ATTS transcription factor CaTec1p regulates hyphal development and virulence in Candida albicans.

The temporal and spatial expression of stage-specific genes during morphological development of fungi and higher eukaryotes is controlled by transcription factors. In this study, we report the cloning and functional analysis of the Candida albicans TEC1 (CaTEC1) gene, a new member of the TEA/ATTS family of transcription factors that regulates C. albicans virulence. The promoters of the type 4, 5 and 6 proteinase isogenes (SAP4-6) contain repetitive TEA/ATTS consensus sequence motifs. This finding suggests a possible role for a homologue of Saccharomyces cerevisiae TEC1 during the activation of proteinase gene expression in C. albicans. CaTEC1 is predominantly expressed in the hyphal form of C. albicans. In vitro, serum-induced hyphal formation as well as evasion from MPhi after phagocytosis is suppressed in catec1/catec1 mutant cells. Furthermore, expression of the proteinase isogenes SAP4-6 is no longer inducible in these mutant cells. The deletion of the CaTEC1 gene attenuates virulence of C. albicans in a systemic model of murine candidiasis, although both mutant and revertant cells that were prepared from infected tissues or the vaginal mucosa grew in a hyphal morphology in vivo. CaTEC1 complements the pseudohyphal and invasive growth defect of haploid and diploid S. cerevisiae tec1/tec1 mutant cells and strongly activates the promoter of FLO11, a gene required for pseudohyphal growth. This study provides the first evidence pointing to an essential role for a member of the TEA/ATTS transcription factor family that had so far only been ascribed to function during development as a virulence regulator in microbial pathogenesis.

Animals↗
PubMed2000

Chondral lesions after arthroscopic meniscus repair using meniscus arrows.

Meniscus repair using bioabsorbable devices has become popular in the last few years. Good clinical results have been reported and few complications have been published. This report describes the case of a 37-year-old male patient with a lateral meniscus repair using 4 Meniscus Arrows (Bionx Implants, Blue Bell, PA). Postoperatively, repeated episodes of intra-articular effusions have occurred. A second-look arthroscopy 8 months after the reconstruction showed that the meniscus tear had not healed and revealed the presence of chondral damage corresponding to the location of the arrows in the posterior area of the lateral femoral condyle. Surgeons using the Meniscus Arrow should be aware of this possible postoperative complication.

Absorbable Implants↗
PubMed2000

Cyclic AMP and fluconazole resistance in Saccharomyces cerevisiae.

Cyclic AMP (cAMP) is involved in the stress response in Saccharomyces cerevisiae. We show that cAMP is required for resistance to fluconazole in S. cerevisiae. In addition, activation of Ras2, a regulator of cAMP generation, results in some protection from fluconazole toxicity in a fashion independent of the efflux transporter Pdr5p.

Antifungal Agents↗
PubMed2000

The influence of avascularity on the mechanical properties of human bone-patellar-tendon-bone grafts.

Our aim was to analyse the effect of avascularity on the morphology and mechanical properties (tensile strength, viscoelasticity) of human bone-patellar-tendon-bone (BPTB) grafts in vitro. These were harvested at postmortem and stored submerged in denaturated human plasma at a constant pH, pO2, pCO2, temperature and humidity under sterile conditions. Mechanical testing was performed two and four weeks after removal of the graft. The mean ultimate strength was 1085.7 +/- 255.8 N (control), 1009.0 +/- 314.9 N (two weeks cultured) and 1076.8 +/- 414.8 N (four weeks cultured). There was no significant difference in linear stiffness or deformation to failure between the groups. There was a difference in viscoelasticity between the control group and the avascular grafts and the latter had significant lower peak load-to-load ratios after 15 minutes compared with the control group. After two and four weeks the graft contained viable fibroblasts. There was regular cellularity in the superficial layers and decreased cellularity in the midportion. The structure of the collagen including the crimp pattern appeared to be normal in polarised light. We conclude that avascularity does not significantly affect ultimate failure loads or stiffness of BPTB grafts. Slight changes in viscoelasticity were induced, but the significance of the increased stress relaxation is not fully understood.

Adult↗