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Biomedical subjects

M Wiedemann

Publications and source records attributed to M Wiedemann.

At least 37 records · Page 2Linked to original sources
PubMed1996

Callus distraction: a new method? A historical review of limb lengthening.

The technique of callus distraction can be traced back to the work of Codivilla at the beginning of the century. Subsequent to Codivilla, various crude methods of limb lengthening were used but resulted in high complication rates. Not until the work of Putti and Abbott in the 1920s and their painstaking operative technique did the results become verifiable. During the 1930s, various modifications were introduced and the apparatus was simplified. However, because of an increasing tendency to apply this technique to unsuitable cases, it fell into disrepute. After World War II, Anderson, Allan, and Ilizarov developed better equipment, allowing for a better understanding of the biologic principles of callus distraction. In the 1980s, this method was adopted for treatment of major bone defects and shortening of limbs.

Bone Lengthening↗
PubMed1995

[Dislocation fracture of the head of the tibia. I. Results of surgical treatment].

Moore's classification of fracture dislocation of the tibial head gives us some clues of concomitant ligament injuries. We did a follow-up of 64 patients with fracture dislocations operated between 1982 and 1991. With these complex injuries we found overall unsatisfactory results regarding subjective and objective stability. We were able to correlate certain patterns of instability with specific Moore types. So a complete assessment of this complex knee-injury can be made from the X-ray and a stability check-up.

Adult↗
PubMed1995

[Dislocation fracture of the head of the tibia. II. Therapeutic procedure].

Fracture dislocations of the tibial plateau have associated pathology including ligament- and meniscus tears. They therefore require different treatment than split- or impression fractures. The operative and nonoperative management depends on the soft tissue injuries including ligament tears and depends also on the functional requirements of the patient. Surgical approach, operative time and protection of vascular supply of soft tissue and bony fragments are the main factors influencing postoperative complications and outcome. The different fracture dislocation types according to the Moore classification require specific types of treatment. This includes open reduction with internal or external fixation as well as arthroscopy.

Adult↗
PubMed1995

[Dislocated intra-articular calcaneus fractures. Long-term follow-up after open reposition and osteosynthesis].

A series of 98 patients with a total of 105 intra-articular fractures of the os calcis were operated on during a 10-year period between 1983 and 1992. We were able to follow up 60 patients with 64 fractures an average of 44 months (range, 18-105 months) postoperatively. At the time of follow up, 83.9% of patients had been back to work, 78.6% with the same employer as before. Five of the patients followed up had had to retire from work; each of these had one or more severe coexisting injuries. A compromising nerve injury occurred postoperatively in 3 out of 58 patients with closed fractures, in all cases following surgery with a medial or bilateral approach. In only 1 of the 58 patients followed up after closed fractures did a deep infection requiring arthrodesis occur. One patient had sympathetic reflex dystrophy (Sudeck). A good functional result in the lower ankle joint correlated with a good outcome. In contrast, postoperative improvement of the tuber angle and the degree of arthrosis seen radiographically did not. We conclude that operative repair of intraarticular calcaneal fractures is a procedure that can safely be procedure used to restore the ability to work in the majority of patients. The medial approach should preferably not be used, nor should the metal be extracted from the medial approach if this can be avoided.

Adolescent↗
PubMed1994

Intraosseous leiomyoma of the neck of the femur. A case report.

Intraosseous benign leiomyoma is a rare manifestation of disseminated leiomyomatosis. In a 54 year old housewife presenting with a painful left hip due to a cystic lesion of the femoral neck, histological assessment following resection of the cyst showed a benign intraosseous leiomyoma. Years before a diagnosis of disseminated peritoneal leiomyomatosis had been made.

Biopsy↗
PubMed1994

[Morphologic principles of callus distraction].

There are various ways and means of performing the callus distraction procedures used more and more frequently in the clinic today. The interplay of numerous factors affects the macroscopical and microscopical morphological appearance and thus the quality of the bone regenerate. The radiological appearance during and after distraction remains relatively constant and is well-known. Tissue maturation occurs in several phases, namely, an organisational, a longitudinal polarisation, an ossification, and a consolidation phase. The characteristic morphological signs of the individual phases will be described.

Animals↗
PubMed1993

Purification and enzymatic characterization of the geranylgeranyl pyrophosphate synthase from Erwinia uredovora after expression in Escherichia coli.

Geranylgeranyl pyrophosphate (GGPP) synthase from Erwinia uredovora was overexpressed in Escherichia coli and purified to homogeneity from solubilized inclusion bodies. In this protein the first 13 N-terminal amino acids were replaced by 16 other amino acids resulting from the cloning vector pUC18. Nevertheless, the enzyme showed activity after purification which could be stimulated sixfold by appropriate activation conditions. The homogeneous enzyme was used to study substrate and product specificity as well as to determine Km values for isopentenyl pyrophosphate, dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP), and farnesyl pyrophosphate (FPP). Reaction rates and Km values indicate that FPP and GPP are the genuine allylic substrates for GGPP synthase, but not DMAPP. Independent of the allylic substrate employed, GGPP was the only reaction product of the enzymatic reaction.

Alkyl and Aryl Transferases↗
PubMed1993

Functional identification of al-3 from Neurospora crassa as the gene for geranylgeranyl pyrophosphate synthase by complementation with crt genes, in vitro characterization of the gene product and mutant analysis.

In this work the Neurospora crassa al-3 gene function was determined. Geranylgeranyl pyrophosphate (GGPP) synthase activity was measured in al-2 FGSC 313 and al-3 RP100 FGSC 2082 mutant strains by in vitro synthesis methods. This experiment showed that al-3 RP100 mutant expresses a reduced GGPP synthase activity. The mutated al-3 gene was cloned and sequenced; a single missense mutation was found changing serine into asparagine. Genetic complementation was performed by Escherichia coli transformation, with clusters of crt genes from Erwinia uredovora. Carotenoid accumulation was observed in E. coli transformants when the N. crassa al-3 gene substitutes the GGPP synthase gene (crtE) in the carotenogenic crt cluster. Cell-free studies with E. coli transformants gave direct evidence of the function of the al-3 protein as GGPP synthase and indicated that a short-chain prenylpyrophosphate, such as dimethylallyl pyrophosphate, is the genuine substrate.

Alkyl and Aryl Transferases↗
PubMed1993

Indications and results of nonoperative treatment of patellar fractures.

It is uncontested that most patellar fractures have to be treated by open reduction and internal fixation. Nevertheless, there are well-defined types of patellar fractures in which such a procedure is unnecessary because the fracture is stable and the retropatellar surface is congruous. In these fractures internal fixation would constitute overtreatment; conservative treatment yields good results in such cases. In this report, 40 patellar fractures treated conservatively were reviewed (average, 30.5 months after injury). Results were assessed subjectively and objectively. Of the 40 patients, 80% were pain free and 90% had a full range of knee motion.

Adult↗
PubMed1992

Molecular characterization of a putative peroxidase gene of Drosophila melanogaster.

We have identified genomic clones and corresponding cDNAs that encode a putative peroxidase of Drosophila melanogaster. The gene (DmPO) appears as a single copy gene located on the third chromosome at position 89 D/E. It is interrupted by seven small introns and one unusually large 5' intron (about 11 kb). Sequence analysis of the cDNA showed an open reading frame of 690 amino acids resulting in a protein of 77 kDa. The deduced amino acid sequence reveals an overall homology to myeloeosinophil and thyroid peroxidase, a human superfamily of peroxidases.

Amino Acid Sequence↗
PubMed1991

[Femoral head preserving therapy in medial femoral neck fractures. A clinical study of the effects of treatment method on the outcome].

The main problem with fractures of the femoral neck is the high incidence of avascular necrosis and non-union. While the rate of pseudarthroses has been lowered by treatment with stable compression screws, no effect of this technique on the incidence of head necrosis is evident. The reasons for this are rupture of vessels, wide dislocation of fragments and diminution of blood supply owing to intracapsular hematoma. Since 1982 we have been using a defined indications and therapy schedule for these fractures, which is based on the main principle of open operative treatment in younger patients. This procedure is the only one that makes accurate reduction and stable internal fixation of fragments possible. With the opening of the capsule and evacuation of the hematoma pressure on the blood vessels is relieved. The analysis of data recorded in 81 patients treated with open reduction and stable internal fixation revealed that poor functional results and avascular necrosis occur especially in fractures of Garden's stages III and IV that are operated on longer than 6 h after the trauma is sustained. Therefore, the operation should be performed as soon as possible as an emergency procedure to reduce the likelihood of such severe complications.

Femoral Neck Fractures↗
PubMed1990

Development of a high performance liquid chromatography method for the simultaneous measurement of prednisone and prednisolone.

An improved high performance liquid chromatographic assay (HPLC) is presented for the quantitative determination of prednisone and its main metabolite prednisolone. This HPLC assay, employing a UV-detector and dexamethasone as an internal standard, provides a selective and sensitive determination of glucocorticoids in plasma. The advantage of this method is the possibility of simultaneously measuring exogenic and endogenic glucocorticoids. The lower limit of quantification is 5 ng/ml.

Chromatography, High Pressure Liquid↗
PubMed1988

[Effect of pancuronium bromide on the adherence of polymorphonuclear neutrophilic granulocytes in vitro].

Infection is still an important problem following surgery. Polymorphonuclear neutrophil granulocytes (PMN) play a vital role in host defenses against invading bacteria; thus, adverse effects on PMN caused by anesthetic agents are of general interest. In this study, we examined the influence of pancuronium bromide on PMN adherence in vitro. Heparinized venous blood samples were obtained from 18 healthy male adult donors. Each specimen was divided. One part was used to determine the adherence of untreated PMN, while pancuronium bromide was added to the other. Two concentrations (1.3 or 0.5 micrograms relaxant/ml blood) were tested. PMN adherence was studied using nylon fiber columns as described by MacGregor et al. Both concentrations of pancuronium bromide caused an inhibition of adherence, which was significant in the case of the higher dosage (p less than 0.05). There is a direct correlation between the intensity of PMN adherence and the extent of granulocyte delivery to sites of inflammation. Therefore, it seems possible that clinical concentrations of pancuronium bromide may be able to increase the risk of developing bacterial infections. Further studies concerning this problem should be conducted.

Adult↗
PubMed1978

[Premonitory blood count changes in the relapse of juvenile acute lymphatic leukemia].

Investigation was done in 80 children with acute lymphocytic leukemia (ALL) with respect to premonitory changes of peripheral blood cell counts before a hematologica relapse. 38 patients suffered from one or more relapses. Evaluation was done by t-test and Friedmann test. 9 weeks before a relapse there was a significant decrease in thrombocytes numbers demonstrable. Granulocytes numbers and monocytes numbers declined 6 and 3 weeks before the relapse, respectively. The lymphocytes counts had already increased 6 weeks before a relapse. The blood cell counts during intercurrent infections did not interfere with the typical pattern of blood cell counts before a relapse. Also the changes in blood cells found are different from those seen in untreated cases of ALL.

Blood Platelets↗