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Biomedical subjects

S Rupp

Publications and source records attributed to S Rupp.

At least 73 records · Page 4Linked to original sources
PubMed1995

Biogenesis of the yeast vacuole (lysosome). The use of active-site mutants of proteinase yscA to determine the necessity of the enzyme for vacuolar proteinase maturation and proteinase yscB stability.

The activation process of vacuolar proteinases in the yeast Saccharomyces cerevisiae via precursor maturation is initiated by the PRA1/PEP4 gene product, proteinase yscA. Chromosomal deletion of the PRA1/PEP4 locus leads to accumulation of inactive pro-proteinases in the vacuole. Nine active-site mutations of proteinase yscA have been constructed in vitro. All these mutations lead to the expression of proteinase yscA species in vivo that are inactive against the in vitro substrate hemoglobin and the in vivo substrates pro-proteinase yscB and pro-carboxypeptidase yscY. However, three active-site mutations in proteinase yscA sustained the precursor maturation of proteinase yscB and carboxypeptidase yscY after exchange of the genomic wild-type allele with the respective proteinase yscA mutant alleles. In contrast to yeast strains deleted in proteinase yscA, the respective mutants carry out all cellular functions that rely on a proteolytically active vacuole. This wild-type behaviour of proteinase yscA mutant cells is dependent on the presence of active proteinase yscB. Proteinase yscA and proteinase yscB are equally able to fulfil essential cellular functions. For instance, either proteinase is able to maintain viability under starvation. However, mature proteinase yscB is not stable in the absence of proteinase yscA. The wild-type-like conformation of proteolytically inactive mutant proteinase yscA proteins stabilizes mature proteinase yscB and thus enables continuous maturation of pro-proteinase yscB by active proteinase yscB. After inhibition of the proteolytic activity of proteinase yscB in these proteinase yscA mutants with phenylmethysulfonyl fluoride or deletion of the PRB1 gene, maturation of all zymogens investigated in the vacuole, including the proteinase yscA mutant proteins, is blocked. The proteolytic activities of the vacuole in such a strain can be regained, however, by introduction of a wild-type proteinase yscA gene allowing subsequent autocatalytic maturation of wild-type pro-proteinase yscA. This indicates that an initial self-activation process of proteinase yscA is necessary for the activation of vacuolar zymogens.

Alleles↗
PubMed1995

[Subacromial impingement. Evaluating the concept--diagnosis--therapeutic concepts].

Subacromial impingement is a condition that belongs to the group of diseases known collectively as periarthritis humeroscapularis and has a typical clinical presentation. The underlying cause is a late of sufficient space of various origin in the subacromial region that finally leads to rotator cuff damage. Depending on cause, three forms can be distinguished, primarily extrinsic, primarily intrinsic and secondary impingement. The diagnosis is primarily clinical (pain on raising the arms above the head, painful arc syndrome). The value of imaging techniques, and the diagnostic approach are described. Initially treatment is always conservative, but when pain becomes severe or function is lost, arthroscopic or open surgical treatment may be needed.

Acromion↗
PubMed1995

Shoulder problems in high level swimmers--impingement, anterior instability, muscular imbalance?

The objective was to study prevalence and underlying pathology of "swimmer's shoulder". Twenty-two competitive swimmers of national "D-Kader" (elite development swimmers) were evaluated by means of questionnaire, clinical examination and isokinetic testing of external rotation and internal rotation. At the examination current interfering pain necessitating a cessation or reduction of practice was found in 5 (23%) athletes. At isokinetic testing 8 (36%) athletes complained of shoulder pain. Any history of pain was seen in 14 (64%) swimmers. A positive impingement sign was noted in 11 (50%) athletes. Apprehension sign which is indicative of anterior instability was found in 11 (50%) swimmers. Clinical equivalents of dysfunction of scapulothoracic muscles such as scapular winging (5 athletes) and shoulder protraction (12 athletes) were noted. For comparison of results of isokinetic testing a control group of non-swimmers was selected matching the group of swimmers exactly in terms of age, sex and dominant side. External rotation/internal rotation ratio of peak torque and total work at 60 deg/sec and 180 deg/sec was significantly lower in swimmers than in controls. The ratio was independent of sex, dominant side, history of pain and pain at examination. During internal rotation competitive swimmers produced significantly higher peak torques and total work than controls. There was no significant difference in external rotation. In conclusion there are several different abnormalities of function contributing to the pathology of "swimmer's shoulder":--Laxity of anterior-inferior capsuloligamentous structures with atruamatic anterior instability due to repetitive overload.--Impingement with rotator cuff tendinitis.--Muscular imbalance of the rotator cuff muscles and scapulothoracic dysfunction.

Adolescent↗
PubMed1995

Ultrasound of the Achilles tendon after surgical repair: morphology and function.

Ultrasound is a well established method for the examination of the Achilles tendon. The objective of the study was to provide answers to the following questions: What ultrasonographic structural changes are long lasting after surgical repair? How important is ultrasound with regards to the functional evaluation of late results? 60 patients were examined at an average 11 years (2-19) after surgical repair of Achilles tendon rupture. In only four patients sonographic morphology of the tendon was according to the non-injured side. A variety of distinct basic alterations in ultrasound morphology was found: a hypoechogenic ribbon ventrally to the dorsal paratenon (n = 40), spots of hypoechogenic areas in the tendon (n = 18), dishomogeneous hyperechogenicity with preservation (n = 12) or dissolving (n = 22) of its fibrillar components along the longitudinal axis. In most of the cases the paratenon was thickened or could not be differentiated. In the dynamic ultrasound examination gliding mechanism of the achilles tendon was limited in 41 patients. Extensive functional subjective and objective parameters of all patients were evaluated in an Achilles tendon score. The results were rated as excellent (n = 18), good (n = 29), satisfactory (n = 12) and poor (n = 1). There was no statistical correlation between ultrasound morphology and clinical outcome. Therefore, it was concluded that ultrasound examination is able to reveal long-lasting alterations in echogenicity of the tendon but is only of limited value with regards to evaluation of the functional results after surgical repair.

Achilles Tendon↗
PubMed1995

[Reduction of the anterior drawer of the knee joint by rehabilitation orthoses. Comparison of the MVP orthosis vs. the Donjoy-Gold point orthosis].

In 20 patients with chronic anterior instability of one knee, two rehabilitation braces (MVP, Donjoy-Gold point) were tested for their ability to limit tibiofemoral translation. A KT-1000 arthrometer was used to quantify the anterior drawer. Both braces significantly reduced passive anterior drawer at 67 N, 89 N and maximal manual shear load and also active anterior drawer. Without a brace the mean anterior drawer was 12.3 mm (67 N), 14.4 mm (89 N), 17.2 mm (maximal manual drawer) and 9.1 mm (active drawer). With the MVP brace the mean anterior drawer was 6.8 mm (67 N), 8.5 mm (89 N), 11.0 mm (maximal manual drawer) and 6.8 mm (active drawer). With the Donjoy brace the mean anterior drawer was 9.2 mm (67 N), 11.0 mm (89 N), 13.1 mm (maximal manual drawer) and 7.4 mm (active drawer). Control values for the non-injured opposite knee were 6.5 mm (67 N), 7.2 mm (89 N), 8.1 mm (maximal manual drawer) and 5.6 mm (active drawer). In direct comparison, the MVP brace provided better stabilization than the Donjoy-Gold point brace did.

Adult↗
PubMed1995

Arthroscopic surgery of the elbow. Therapeutic benefits and hazards.

In this study, 22 patients were reviewed who underwent arthroscopic surgery of the elbow mainly for loose bodies or osteochondrotic lesions. Of these, 12 patients rated the result as good or excellent, 4 had slight improvement, and 6 were not satisfied. The average score (Hospital of Special Surgery scoring system; maximum 100 points) was raised from 70 points to 87 points after surgery. Patients with loose bodies in the elbow and no severe damage of the articular cartilage benefitted most. The results in patients with marked degenerative changes differed considerably.

Adult↗
PubMed1995

[Clinical relevance of tunnel position and interference screw location after replacement-plasty of the anterior cruciate ligament with a patellar ligament transplant].

Fifty-eight patients had a prospective follow-up examination 1 year after arthroscopic ACL replacement. Stability measurement was done using a KT-1000 arthrometer. The side-to-side difference was less than 2 mm in 40 patients, 2-4 mm in 11 patients and more than 4 mm in 7 patients. The position of the tibial and femoral tunnels and interference screw was measured from the postoperative X-ray. The positions of screws and tunnels were highly variable. However, there was no statistical correlation between the position of the femoral interference screw and stability measurement or between the position of the femoral interference screw and flexion contracture or between the position of the tibial interference screw and the extension contracture. However, out of six patients with the femoral tunnel in an extremely anterior position (> 20 mm anterior of the over the top position), only one patient had a stable joint (< 2 mm difference in KT 1000 with 89 N anterior shear load) at follow-up. A screw divergence of more than 10 degrees was found in 18 patients. A tibial interference screw with more than 30 degrees of divergence was seen in seven patients. The primary fixation strength of the bone block could be diminished in these cases. This may have an impact on the early rehabilitation protocol.

Adolescent↗
PubMed1994

[Biomechanical principles of after-care in replacement of the anterior cruciate ligament].

The patellar tendon graft replacing the anterior cruciate ligament undergoes histomorphological and biomechanical changes. From literature we can estimate a force of 200 N to be a critical limit of graft load after ACL-plasty in humans. The comparison with the graft loads under various conditions provided the following conclusions: Unlimited passive motion of the knee joint can be done without risk. Early weight bearing is possible. Active extension exercise against gravity could damage the graft in the range of 0 to 20 degrees of flexion in some patients. A rehabilitation protocol has to regard these biomechanical principles. In a prospective study 74 patients underwent rehabilitation according to the protocol described. An extension contracture of more than 10 degrees was seen in 9 patients. In all cases it was due to a notch-impingement or a cyclops. One year after operation 57 patients had a follow up. The side to side-difference in anterior drawer measured with a KT-1000-arthrometer was less than 2 mm in 45 patients. Six patients had difference between 2 and 4 mm. In six patients the difference was more than 4 mm.

Adolescent↗
PubMed1994

[Functional orthoses in insufficiency of the anterior cruciate ligament. Biomechanical comparative studies in vivo and with a model].

UNLABELLED: We tested 4 functional braces for anterior cruciate ligament insufficiency (CTI, Lennox Hill, Ultratech, Proshifter) in vitro and in vivo. In vitro all braces limited the anterior drawer. The maximal anterior drawer was 3.08 mm (CTI), 5.16 mm (Ultratech), 6.25 mm (Lennox-Hill), 7.33 mm (Proshifter). In vivo anterior drawer was controlled at low shear loads (67 N). With high shear loads the anterior drawer was significantly reduced but the tibiofemoral translation was significantly reduced but the tibiofemoral translation was higher than in the uninjured knee. Without brace: 16.25 mm; CTI: 10.15 mm; Ultratech: 12.10 mm; Lennox-Hill: 9.80 mm; Proshifter: 12.75 mm; CONTROL: 8.05 mm. The active anterior drawer was reduced but not normalized by all braces. Without brace: 8.75 mm; CTI: 5.35 mm; Ultratech: 5.6 mm; Lennox-Hill: 5.45 mm; Proshifter: 6.75 mm; CONTROL: 4.25 mm. None of the braces tested could control the rotation efficiently.

Anterior Cruciate Ligament↗
PubMed1994

[Delayed management of rupture of the Achilles tendon. Long-term follow-up in comparison with early operation].

At the Orthopedic Clinic of the University Homburg/Saar 32 delayed (8 days to 7 months) treated ruptures and 32 immediately (< 48 hours) treated ruptures of the Achilles tendon were followed up by clinical tests and sonographic examination and were compared with regard to the final results and the complications. There was no significant difference in the functional results. The rate of complications, which made a second operation necessary, was significantly higher in the group of delayed repair of the Achilles tendon rupture.

Achilles Tendon↗
PubMed1994

[Arthrofibrosis after replacement-plasty of the anterior cruciate ligament--incidence, causes, therapy].

The objective of the study was to assess prospectively the percentage of patients with restricted range of motion (arthrofibrosis) after ACL-plasty and to assess the clinical benefit of arthroscopic surgery. We had arthrofibrosis in 9 out of 74 cases (12%). In 8 cases there was a combined lag of flexion and extension and in one case there was only a lag of extension. In all patients range of motion could be improved by arthroscopic surgery. There was a significant raise in extension (13.3 degrees) and in flexion (28.7 degrees). In the arthrofibrosis-group more patients had undergone surgery for acute ACL-rupture (66%) than in the group without arthrofibrosis (32%).

Adolescent↗
PubMed1994

Lateral tibial avulsion fractures and disruptions to the anterior cruciate ligament. A clinical study of their incidence and correlation.

Avulsion fractures of the lateral tibial plateau, known as the lateral capsular sign, are increasingly associated with anterior cruciate ligament (ACL) ruptures. This phenomenon, known as the Ségond fracture, is a bony avulsion of the menisco-tibial ligament. Stress, which can lead to an avulsion of this kind, almost always occurs during knee flexion and internal tibial rotation, and in most cases only after damage to the primary ACL stabilizer. Examination of 151 ACL ruptures revealed a Ségond fracture in 9% of patients. Nearly all were caused by sports injuries and, understandably, the accident mechanism always included knee flexion and internal rotation of the tibial. In a similarly large number of other knee injuries without damage to the ACL, only one case of a Ségond fracture was found. This phenomenon, which is easy to detect by radiograph, can thus be regarded as a strong indication of the presence of a ligament injury.

Anterior Cruciate Ligament Injuries↗
PubMed1993

Vacuolar/lysosomal proteolysis: proteases, substrates, mechanisms.

Proteolysis is an essential post-transcriptional process. The lysosome/vacuole is the central organelle for non-specific proteolysis in eukaryotes. Most proteases that work in the lysosome enter it via the secretory pathway. The bulk of proteins to be degraded enter this proteolytic compartment via endocytosis and autophagocytosis. Our understanding of the mechanisms involved in these processes has increased considerably, and the information obtained in these studies has enabled new, specific proteolytic pathways to be investigated in other cellular compartments, particularly in the cytoplasm.

Animals↗
PubMed1993

Biogenesis of the yeast vacuole (lysosome). Signal sequence deletion of the vacuolar aspartic proteinase yscA does not block maturation of vacuolar proteinases.

The activation process of vacuolar (lysosomal) proteinases in the yeast Saccharomyces cerevisiae is initiated by the PRA1 (PEP4) gene product, proteinase yscA. To elucidate the importance of the different domains of proteinase yscA in a first attempt the signal sequence of the enzyme was deleted using site-directed mutagenesis. Proteinase yscA delta S underwent processing to an active enzyme, although the amount of mature enzyme was considerably reduced as compared to wild type. Isolation of vacuoles of the mutant strain showed mature-sized proteinase yscA in this organelle. Pro-proteinase yscB is converted to 5-10% to the mature enzyme, whereas procarboxypeptidase yscY is matured, although with reduced kinetics. Thus, the signal sequence of proteinase yscA is not essential for delivery to the vacuole and the activation of a certain amount of the yeast vacuolar proteolytic capacity.

Aspartic Acid Endopeptidases↗
PubMed1991

Biogenesis of the yeast vacuole (lysosome). Active site mutation in the vacuolar aspartate proteinase yscA blocks maturation of vacuolar proteinases.

The activation process of vacuolar (lysosomal) proteinases in the yeast Saccharomyces cerevisiae is initiated by the PRA1 (PEP4) gene product, proteinase yscA. To elucidate the activation process of proteinase yscA the catalytically active amino acid Asp294 of the enzyme was exchanged with Ala294 using site directed mutagenesis. The resulting proteinase yscA-Ala294 showed no proteolytic activity against the substrate hemoglobin. The mutant protein did not undergo processing in vivo. This phenomenon is in good agreement with the hypothesis that maturation of proteinase yscA is due to self-processing of pro-proteinase yscA. Furthermore, proteinase yscA-Ala294 is not able to convert the zymogens pro-proteinase yscB and pro-carboxypeptidase yscY to the mature enzymes.

Amino Acid Sequence↗
PubMed1987

[The effect of metamizole on gastric emptying and small intestine transit in the rat].

The effect of the pyrazolone derivative metamizole on the motility of the upper gastrointestinal tract of the rat was investigated. An animal model for simultaneous quantification of gastric emptying and small intestinal transport was used. A test meal with different radioactive labels was administered by means of previously implanted tubes both to the stomach (1.0 ml; 51Cr) and to the duodenum (0.25 ml; 99mTc), and the spatial distribution of both isotopes in a gastrointestinal preparation was determined after a transport time of 30 min. It has been shown that intravenously administered metamizole reduces significantly the percentage of the test meal discharged by the stomach (control: 70.9 +/- 2.8; 50 mg/kg metamizole: 26.3 +/- 6.9, p less than 0.001; 250 mg/kg metamizole: 3.8 +/- 1.5, p less than 0.001); 1250 mg/kg metamizole: 1.1 +/- 0.3; p less than 0.001). The 50- and 250-mg/kg doses had no negative effect on the propulsion of the small intestine. A dose of 1250 mg/kg induced a significant reduction in small intestinal transport (p less than 0.001).

Aminopyrine↗