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Biomedical subjects

W Menke

Publications and source records attributed to W Menke.

49 records · Page 3Linked to original sources
PubMedDate not supplied

[Bone density measurements of the proximal femur in relation to torsion of the femoral neck].

The DEXA-method allows for bone mineral density measurements of different regions of the skeletal system. It is known that results obtained from the spine with this two-dimensional method may be biased in cases of spondylosis, spondylarthritis, and compression fractures; similarly biased results can be expected at the proximal femur due to morphometric peculiarities. The influence of anteversion and rotation of the femoral neck has been investigated in the present study. The results indicate that errors due to rotation as occurring in incorrect positioning or in arthrogenic variabilities mainly have effects on measurements of Ward's triangle: The average measurement error at 20 degrees external rotation amounts to 33.8% with a maximum of 66.5%. Measurements of the trochanteric region and of femoral neck region show a variation of 6.2% and 9.7%, respectively.

Absorptiometry, Photon↗
PubMedDate not supplied

[5-10-year results with the straight-shaft Müller prosthesis].

103 patients with 106 Müller straight stem prostheses could be evaluated clinically and radiologically after an average follow-up period of 6.8 years (range 5 to 10 ys.). Although until now no revision for aseptic loosening has become necessary 3 p.c. of the stems and 11 p.c. of the acetabular components showed radiological loosening. The clinical results were rated as satisfactory. After surgery 67 p.c. of the patients were completely painfree, 28 p.c. still had slight pain, 4 p.c. moderate and 1 p.c. severe pain. The investigation concentrated particularly on radiographic changes of the interface of the femur. Whereas radiolucency typically was non-progressive and located in the proximal part of the femur we found an increasing atrophy of the cortical bone on the calcar. Moreover, we found a continuous and increasing subsidence of the stem during the whole period of observation. At the time of follow up 56 p.c. of the straight stems had subsided about 2 mm and more. Calcar atrophy and radiolucency were significantly less present in femurs with a tapered medullary canal than in those with a cylindrical shape.

Acetabulum↗
PubMedDate not supplied

[Transverse skeletal axes of the lower extremity in coxarthrosis].

Femoral anteversion, anteversion of the acetabulum and tibial torsion of 47 patients with idiopathic osteoarthritis of the hip were determined by computerized tomography. From all these parameters only the anteversion of the acetabulum showed differing values in hips with and without osteoarthritis. There was a considerable range at the individual measured values in all parameters and differences between the male and female groups could be found in femoral anteversion and anteversion of the acetabulum.

Biomechanical Phenomena↗
PubMedDate not supplied

[Dorsal patellar defect].

A case report of a dorsal defect of patella is presented and discussed in comparison with the Osteochondrosis dissecans of the patella.

Adolescent↗
PubMedDate not supplied

[EMG-controlled postoperative exercise therapy using the ELMOBIL].

On the basis of clinical cases, the application possibilities of a newly developed portable EMG amplifier in the field of physiotherapy. The device permits continuous recording of the EMG activity of the muscles requiring therapy over any desired period of time.

Adult↗
PubMedDate not supplied

The effect of an antiserum to plastocyanin on various chloroplast preparations.

A monospecific antiserum to tobacco plastocyanin agglutinates stroma-free swellable chloroplasts from wild type tobacco, (Nicotiana tobacum var. John William's Broadleaf) from the tobacco aurea mutant Su/su2, (Nicotiana tabacum var. Su/su2) from Antirrhinum majus and spinach (Spinacia oleracea). In this condition the antiserum inhibits linear photosynthetic electron flow in tobacco and spinach chloroplasts. This inhibition of electron transport as well as the agglutination are not observed if the chloroplasts have been sonicated prior to antiserum addition. This is due to the fact that plastocyanin is removed by ultasonication. The antiserum stimulates a number of photophosphorylation reactions in tobacco chloroplasts. This stimulation is always larger in the aurea mutant chloroplasts from yellow leaf patches of a variegated tobacco mutant (N. tabacum, var. NC 95) than in the green type chloroplasts. The stimulation appears to be a consequence of the inhibition of linear electron transport. The antiserum does not affect PMS-mediated cyclic photophosphorylation in tobacco chloroplasts from the wild type whereas the reaction appears stimulated in the tobacco mutant chloroplasts. However, menadione-mediated cyclic photophosphorylation is inhibited upon addition of the antiserum. The same is true for noncyclic photophosphorylation coupled to electron transport in the aerobic system diaminodurene/ascorbate leads to methylviologen in the presence of N-tetraphenyl-p-phenylenediamine in spinach chlorplasts. If the lamellar system of Antirrhinum and spinach has lost is swellability neither agglutination nor inhibition of electron transport is observed. However, also in this state antibodies to plastocyanin are specifically adsorbed onto the surface to the thylakoid membrane. This state which is characterized by a morphologically well preserved lamellar system is realized in chloroplast preparations from Antirrhinum and spinach and is termed stroma-freed chloroplasts. In both states of the molecular structure of the thylakoid membrane, plastocyanin is located in the outer surface of the thylakoid. However, it cannot be excluded that functioning plastocyanin is also located in the interior of the thylakoid membrane.

2,6-Dichloroindophenol↗
PubMedDate not supplied

Inhibition of electron transport on the oxygen-evolving side of photosystem II by an antiserum to a polypeptide isolated from the thylakoid membrane.

A polypeptide fraction with the apparent molecular weight 11 000 was isolated from stroma-freed chloroplasts from Anthirrhinum majus. An antiserum to this polypeptide fraction inhibits photosynthetic electron transport in chloroplasts from Nicotiana tabacum. The relative degree of inhibition is pH dependent and has its maximum at pH 7.4. The maximal inhibition observed was 93%. The dependence of the inhibition on the amount of antiserum yields a sigmoidal curve which hints at a cooperative effect. A calculation of the Hill interaction coefficient gave the value of 10. The inhibition occurs on the water splitting side of photosystem II between the sites of electron donation of tetramethyl benzidine and diphenylcarbazide. Tetramethyl benzidine donates its electrons before the site where diphenylcarbazide feeds in its electrons. Analysis of the steady state level of the variable fluorescence also indicates that the inhibition site is on the water splitting side of photosystem II. Tris-washed chloroplasts are equally inhibited by the antiserum and the inhibition is also observed in the presence of an inhibitor of photophosphorylation like dicyclohexyl carbodiimide and in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone (CCCP) which means that the inhibitory action is directed towards the electron transport chain. Valinomycin which is supposed to affect the cation permeability of the thylakoid membrane has no influence on the inhibitory action of the antiserum. The same is valid for gramicidin. Methylamine on the other hand can induce a state in the thylakoids in which the antiserum is not effective. If the antibodies are already adsorbed prior to the methylamine addition then the high inhibitory effect by the antiserum remains unchanged upon addition of methylamine. From the experiments it follows that a component from the vicinity of photosystem II is accessible to antibodies that is, the component is located in the outer surface of the thylakoid membrane. It appears that the inhibitory effect is produced in the course of the light reaction.

Benzidines↗
PubMedDate not supplied

Effect of an antiserum to a thylakoid membrane polypeptide on the primary photoreaction of photosystem II.

As was described previously, an antiserum to polypeptide 11000 inhibited photosynthetic electron transport on the oxygen evolving side of photosystem II. The effect of the antiserum on chloroplasts from two tobacco mutants also clearly showed that the inhibition site is on the photosystem II-side of the electron transport chain. One of the two tobacco mutants lacks the oxygen evolving capacity but exhibits some electron transport with tetramethyl benzidine, an artificial donor to PS II. In this mutant electron transport was barely inhibited. The effect of the antiserum on the primary photoevents showed that the initial amplitude of the absorption change of chlorophyll aII at 690 nm and that of the primary electron acceptor X320 at 334 nm both diminished in the presence of the antiserum. Both signals were restored upon addition of diphenylcarbazide another artificial donor to photosystem II. Comparison of the degree of inhibition on the amplitudes of the fast and slow components of the 690 nm absorption change with the manometrically measured inhibition of electron transport shows that besides a full inactivation of a part of the reaction centers of photosystem II another part apparently mediates a fast cyclic electron flow around photosystem II as reported by Renger and Wolff earlier for tris-treated chloroplasts. Moreover, the antiserum affects the low temperature fluorescence in a way which is opposite to Murata's effect of the Mg2+-ion induced inhibition of energy spill-over from photosystem II to phytosystem I. The antiserum under the condition in which the Hill reaction is inhibited lowered the 686 nm emission and enhanced the 732 nm emission which indicates an enhanced energy spill-over to photosystem I.

Chloroplasts↗
PubMedDate not supplied

Localization and functional characterization of three thylakoid membrane polypeptides of the molecular weight 66000.

Three polypeptide fractions with the apparent molecular weight 66 000 were isolated from stromafreed Antirrhinum chloroplasts which were solubilized with dodecyl sulfate. Antisera to these fractions affect electron transport in distinctly different ways. For the characterization of the three antisera photochemical reactions of chloroplast preparation with artificial electron donors and acceptors as well the analysis of fluorescence rise curves were used. Antiserum 66 000 PSI-96 inhibits electron transport apparently on the acceptor side of photosystem I, provided the antibodies are adsorbed onto the outer surface of the thylakoid membrane. Antiserum 66 000 PSI-88 probably acts directly on the reaction centre I or on its immediate vicinity, if the antibodies are adsorbed at the inner surface of the thylakoid membrane. Antiserum 66 000 PSII-42 inhibits electron transport in the region of photosystem II. The antigen towards which the antiserum is directed appears to belong to the reaction centre II, as also in the condition of high inhibition degrees, the fluorescence intensity remains unchanged. The determinants are located at the outer surface of the thylakoid membrane.

Antibodies↗