Biomedical subjects

R Theiler

Publications and source records attributed to R Theiler.

61 records · Page 4Linked to original sources

PubMed1983

N-terminal sequences of subunits L and M of the photosynthetic reaction centre from Rhodospirillum rubrum G-9+. Separation of the subunits by gel filtration on hydroxypropylated Sephadex G 100 in organic solvents.

A new method has been developed by which subunits L and M of the photosynthetic reaction centre from Rhodospirillum rubrum G-9+ can be obtained in pure form, starting form freeze-dried chromatophore membranes. The method employs extraction into a mixture of chloroform/methanol and gel permeation chromatography on a column of hydroxypropylated Sephadex G 100. Cross-contamination of the purified subunits was less than 5% (mol/mol), as estimated by manual Edman degradation. Automated Edman degradation has been carried out with both subunits in a liquid-phase sequencer. 36 amino-acid residues of subunit L and 50 residues of subunit M could be unequivocally identified. In both cases, the sequence analyses came to a premature end as the signal sudden by dropped to the level of the accidental fluctuations of the phenylthiohydantoin-derivatives background. This effect is explained by the unusual susceptibility to peptide bond cleavage of certain threonine residues which probably underwent N leads to O acyl shift during the cleavage reactions. The N-terminal sequences have been compared to those of subunits L and M of the photosynthetic reactions centre from Rhodopseudomonas sphaeroides R-26 (sutton, M.R., Rosen, D., Feher, G. & Steiner, L.A. (1982) Biochemistry 21, 3842-3849). The homology among subunits L is close to 90% and thus markedly higher than that among subunits M (32%). This finding indicates a pre-eminent role of subunit L in the primary events of photosynthetic energy conversion.

Amino Acid Sequence↗

PubMed1981

Lateral organization of proteins in the chromatophore membrane of Rhodospirillum rubrum studied by chemical cross-linking.

The organization of proteins in the chromatophore membrane, particularly of the reaction center and the light-harvesting polypeptide, was examined by the use of a hydrophobic and a hydrophilic cross-linking reagent, namely DSP (dithiobis-succinimidyl propionate) and glutaraldehyde. The linkage of proteins was studied by SDS polyacrylamide pore gradient electrophoresis. DSP was shown to link proteins within the core of the membrane. The subunit H of the reaction center is linked with DSP at a low concentration, either with itself or with other membrane proteins but not to the subunits M and L. In isolated reaction centers the subunits H are exclusively linked with each other. With increasing concentrations of DSP the bands of the subunits M, L, and the light-harvesting polypeptide disappear simultaneously from the gel, suggesting that these proteins are linked together. This hypothesis is supported by the finding that reaction centers isolated from chromatophores treated with DSP retain an appreciable amount of light-harvesting polypeptide. With increasing concentrations of the hydrophilic cross-linking reagent glutaraldehyde, the bands of all the three subunits of the reaction center, H, M, and L, progressively disappear from the gel, suggesting that they are linked together. The light-harvesting polypeptide remains free when this reagent is used.

Aldehydes↗

PubMedDate not supplied

[Clinical results 2 years after total hip replacement (WOMAC/SF-36) and comparison with the normal population (SF-36)].

AIM: The aim of this study was to determine the outcome after total hip replacement (THR) with the WOMAC and the SF-36 as well as to identify the most responsive items and to elucidate the reasons for increased pain postoperatively. METHODS: 73 patients filled out the questionnaires preoperatively and 3, 6, 12, 24 months postoperatively. All mean subscales and the responsiveness for each question were calculated. The patients with increased pain postoperatively were reassessed. RESULTS: All WOMAC subscales and six of the eight SF-36 subscales showed significant improvements after THR (p < 0.05). The most responsive items were the pain and disability questions (SRM, ES > 1.5). Two patients with a higher pain score postoperatively had associated symptomatic degenerative lumbar spinal disease. CONCLUSIONS: The WOMAC and the SF-36 are valid measures of the outcomes of THR in their German translations and document the good results after THR. Two years after THR the patients reach the same health state compared to an age matched control group in the population. The WOMAC contains more questions of higher responsiveness than the SF-36. A higher pain score postoperatively may be caused by degenerative disease of the lumbar spine.

Activities of Daily Living↗

PubMedDate not supplied

[Pain reduction by trans-articular atlanto-axial screw fixation in patients with chronic polyarthritis].

To reduce the risk of cervical myelopathy, 32 patients suffering from rheumatoid arthritis (RA) and atlanto-axial dislocation (AAD) underwent a suboccipital fusion. All patients were interviewed with a pain questionnaire after a mean postoperative follow-up of 21 months (range 2-46). The results indicate a significant postoperative pain reduction as assessed by a visual numeric analogue scale, as well as a reduction of analgesic consumption.

Adult↗

PubMedDate not supplied

[Is transcranial magnetic stimulation a helpful method in diagnosis of cervical myelopathy in patients with chronic polyarthritis?].

Fifty-seven patients with rheumatoid arthritis were examined clinically, radiologically, and by means of transcranial magnetic brain stimulation. With this method central motor conduction times of the corticospinal pathways can be measured. The aim of the study was to compare the different methods to detect a cervical myelopathy and to correlate them. In 90% of patients clinical signs of cervical myelopathy could be detected, although in two-thirds of these, the neurological deficit was minimal. Radiologically, over 50% of patients had an atlanto-axid dislocation (AAD) of more than 5 mm. The central motor latencies measured in the upper extremities were prolonged in 47% of cases. These results show the usefulness of transcranial magnetic brain stimulation as an additional noninvasive investigation for detecting compression of the cervical myelon. This is an additional useful criterion for determining the need for operative intervention.

Adult↗

PubMedDate not supplied

[Evaluation of a German version of WOMAC (Western Ontario and McMaster Universities) Arthrosis Index].

The WOMAC (Western Ontario and McMaster Universities) Osteoarthritis Index is a tested questionnaire to assess symptoms and physical functional disability. We adapted the WOMAC for the German language and tested its metric properties, test-retest reliability and validity in 51 patients with knee and hip OA. All WOMAC scales (pain, stiffness, function) were internally consistent with Cronbach's coefficient alpha ranging from 0.80 to 0.96. Test-retest reliability was satisfactory with intraclass correlation coefficients ranging from 0.55 to 0.74. All scales and the global index calculated as the mean of scale scores had a bimodal distribution and a slight ceiling effect. As hypothesized the WOMAC scales were associated with radiological OA-severity and limitations of range-of-motion. Patients with more severe symptoms and functional disability perceived more limitations in their roles at home and at work. The presented German version of the WOMAC is a reliable and valid instrument for the assessment of symptoms and physical functional disability in patients with knee and hip OA.

Activities of Daily Living↗

PubMedDate not supplied

[Evaluation of a German questionnaire version of the Lequesne cox- and gonarthrosis indices].

The Lequesne algofunctional indices for the knee and the hip require a physician interview. We adapted the Lequesne indices for the German language and tested the metric properties, test-retest reliability and validity of a self-report questionnaire-format in 51 patients with hip or knee OA. The symptom and function components as well as the global indices had a high test-retest reliability (intraclass correlation coefficient knee: 0.87/0.92 and 0.86, hip: 0.96/0.85 and 0.94). The symptom component showed an insufficient internal consistency (Cronbach's coefficient alpha knee: 0.55; hip: 0.63). Also, the symptom component was not or only weakly associated with radiological OA-severity and the limitations of range-of-motion. The most likely explanation is the grading of the Lequesne symptom questions which addresses such different concepts as pain presence, pain on movement, duration of pain and appearance of pain after a certain period of time. Because of the insufficient internal consistency and questionable validity the tested self-report German-version of the Lequesne algofunctional indices may not be recommended for use in clinical research and practice.

Activities of Daily Living↗