Biomedical subjects

W Thoma

Publications and source records attributed to W Thoma.

22 records · Page 2Linked to original sources

PubMedDate not supplied

[Diagnosis--therapy and documentation].

The procedures of documentation of diagnostic findings are well established--but different in their graphical and structural appearance of patients histories. Out of multiple findings a retrieval with valid informations is very clumsy. In order to increase quality a complete and reliable registration of clinical data base is necessary. For this purpose the use of electronic media is profitable if the requirements of the data-base are well defined. A nationwide agreement on one key-system--including the transformation of textual structures--is proposed. Only this way leads to comparable results in therapeutic procedures.

Data Collection↗

PubMedDate not supplied

[Computer-assisted analysis of the kinematics of the upper ankle joint].

Usually the upper ankle joint is described as a typical hinge though it had been often remarked that the axis of rotation moves considerably with regard to the angular adjustment between the tibia and the trochlea tali. In the present study the relation between the movements in the upper ankle joint and the geometry of the lateral ligaments was analysed. The contours and elected landmarks of 6 dissected ankle joints were measured using a digitizer which allowed the computerized scanning of motion x-rays. In addition the proximal and distal insertion planes of the lateral ligaments were registered. Mathematical procedures were applied on the experimental data to predict the kinematic principles. The model of an hinged joint could not reproduce the motion curve which was actually found. Using the model of a link chain with four pivots, which was determined by the course of the talofibular and the calcaneofibular ligament, a good correlation with the experimental results was evident. This model implies a rotary and gliding component in the movement of the tibia against the trochlea tali. Beside the correspondence with the data of the present study the model allows an easy explanation of many other well known morphologic phenomena of the upper ankle joint for which a stringent interpretation was not yet available.

Ankle Joint↗

PubMedDate not supplied

[Validation of computerized tomography antetorsion angle measurement of the femur].

AIM OF THE STUDY: Several CT-procedures exist to determine rotational variances of the femur. However, solely on the basis of few CT-scans and without a three-dimensional reconstruction of the femur, it is impossible to define the exact course of the femoral neck axis. Looking for determination of the exact course of the femoral neck axis, auxiliary constructions need to be called upon. Aim of the study was to validate several existing CT-procedures and analyse their respective error rates. METHOD: Fourty-five femora were CT-scanned and subsequently reconstructed three-dimensionally in this study. Femoral anteversion was measured using three different CT-methods in each of these femora and in addition, the respective anatomical anteversion was determined in each femur. In order to test the reliability of such methods, flexion of the femora around the center of the femoral head as well as a varus deformity of the longitudinal axis of the femora were simulated and anteversion measurements were repeated in such simulated positions. Results were statistically analysed using SPSS. RESULT: All tested CT-methods, when compared to the anatomical anteversion of a femur, showed differing anteversion-angles with statistical significance (p < 0.001). Equally, the results of the individual methods tested differed with significance. Due to a high correlation with the anatomical anteversion, all methods examined expressed trend of anteversion. Under simulated hip flexion, the "Ulmer Method" produced different values with statistical significance which were, however, without correlation to anteversion values in joint extension. With statistical significance, the "Essener Method" produced different anteversion values when the longitudinal axis of the femur was modified; however, these values highly correlated to anteversion values of femora with unchanged longitudinal axis. CONCLUSION: Our results lead us to conclude that the "Essener Method" being an interindividual method and independent from positioning, is the most suitable procedure as it allows for the correction of errors with respect to anatomical anteversion.

Femur↗

PubMedDate not supplied

Synthesis of fluorochromes and pigments in Malassezia furfur by use of tryptophan as the single nitrogen source.

A new minimal medium consisting only of L-tryptophan (L-Trp) and a lipid source induced formation of brown pigmentation only in the species Malassezia furfur, which diffuses into the agar. Strains of the species M. sympodialis and M. pachydermatis failed to grow on this medium. On mDixon medium, however, after replacement of peptone by L-Trp, growth of all three Malassezia species was achieved. Under these conditions pigment production was observed with all M. furfur strains tested, although the results for M. pachydermatis strains were inconsistent. M. sympodialis strains showed no pigment production. On the minimal medium pigmentogenesis was induced in M. furfur by only 0.01 g% tryptophan; the pH optimum was pH 5. In all M. furfur strains, alternative amino nitrogen sources given concurrently with Trp suppressed pigmentogenesis. Furthermore, there were differences in the optimal temperature among the individual M. furfur strains. CBS 7019, CBS 6000 and CBS 6001 failed to produce pigment at 37 degrees C. The extract of the culture exhibited remarkable fluorescence, and several indole derivatives with a broad spectrum of colours were detected. This finding may have an impact on the clinical appearance of pityriasis versicolor, a very common skin disease caused by lipophilic yeasts of the genus Malassezia. We hypothesize that in pityriasis versicolor metabolic adaptation of Malassezia yeasts to altered nitrogen conditions on superficial skin might be of patho-physiological importance. Tryptophan as an inducer of pigmentogenesis probably accumulates during excessive sweating, a well-known manifestation of pityriasis versicolor.

Fluorescent Dyes↗