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Biomedical subjects

A Straub

Publications and source records attributed to A Straub.

22 records · Page 2Linked to original sources
PubMed1991

[Sources of error in sonographic diagnosis of the rotator cuff].

Sonography of the shoulder joint has developed into an established examination technique in the diagnosis of periarticular lesions of the shoulder. Sonographic diagnosis of the rotator cuff in particular contains a multitude of possible errors, which are gone into by this study by means of 149 clinically, radiologically and sonographically examined shoulder patients with an average age of 50.5 years. Besides errors made by wrong examination technique such of the transducer as incorrect adjustment of the equipment, insufficient contact of the transducer with the skin and unsuitable choice of the examination plane, there are sources of errors in the interpretation of the sonogram caused by lack of knowledge about physically caused artifacts and sonoanatomical qualities of the shoulder joint. Calcification inside the rotator cuff and the so-called "sonographic inhomogeneity of the rotator cuff" are numbered among the sources of error particular to the shoulder joint. Most errors in sonographic diagnosis of the rotator cuff can be avoided by careful examination of both shoulder joints with an exactly tuned ultrasound device, taking into account the sonoanatomical and ultrasonic qualities. Radiological examination of the affected shoulder joint cannot be replaced by ultrasound.

Diagnostic Errors↗
PubMed1987

Preparation and characterization in solution of oligonucleotides alkylated by activated carcinogenic polycyclic aromatic hydrocarbons.

The effects of aralkylation of selected oligonucleotides by a bulky chemical carcinogen, 7,12-dimethylbenz(a)anthracene (after activation) have been studied. The aralkylation involves the base adenine, designated A* at the modification site, in the center of synthetic heptameric, nonameric and pentadecameric oligonucleotides; complementary strands lacking any modification were also synthesized. The products were studied by UV melting curves and CD spectral techniques. Duplex formation was modified by such aralkylation of a central base in the oligomers. The extent of duplex formation was found to depend on chain length as follows: no evidence was found for duplex formation of the heptamer d(GTCA*GAC) + d(GTCTGAC); the nonamer, d(GTGCA*ATCC) + d(GGATTGCAC), appears to form a duplex at high salt concentrations and reduced temperature; the pentadecamer, d(CCGCT-GCGA*TCCGGC) + d(GCCGGATCGCAGCGG), forms a duplex at low salt concentration and room temperature, but its melting temperature is lower than that of the nonalkylated parent system. CD-spectra for the duplexes formed by the nonamer or pentadecamer are indicative of a right-handed helical conformations. On phosphordiesterase digestion it appears that the aralkylated adenine and the base on its 5'-side act as "stops" for enzymatic digestion from either direction. We suggest, from model building, that this inhibition of phosphodiesterase activity is the result of the steric bulk and disposition of the polycyclic aromatic hydrocarbon. We further suggest that unusual base pairing (mismatching), such as A...A, which would lead to an AT transversion, may be favored by the bulkiness of the aromatic group.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

[Isokinetic strength of lumbar muscles in patients with chronic backache].

Lumbar isokinetic strength and the influence of age, bodyweight and testing velocity in patients with chronic low back pain in comparison with persons without pain. Lumbar isokinetic strength parameters of 80 patients with chronic low back pain and 70 persons without pain were compared and the influence of age, bodyweight and testing velocity was evaluated. The patients with chronic low back pain showed less strength than the persons without pain. All parameters of extension discriminated between the two groups whereas only some of the flexion parameters did. The isokinetic strength of the lumbal extension muscles was higher than the strength of the flexion muscles. In patients with chronic low back pain, isokinetic strength of lumbar extension muscles was more reduced than the strength of flexion muscles in comparison with persons without pain. At 90 degrees/sec in comparison to 60 degrees/sec, lower extension forces, higher flexion forces and changed ratios of flexion and extension muscles were measured. Age had an influence only on women. There were no changes in ratios of flexion and extension muscles with increasing age. Bodyweight showed weak correlations with isokinetic flexion forces. The influence of different factors on isokinetic force varies between patients with chronic low back patients and healthy subjects.

Adolescent↗