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Biomedical subjects

R Jakob

Publications and source records attributed to R Jakob.

27 records · Page 2Linked to original sources
PubMed1989

The impact of computed tomography in the diagnosis and postoperative follow-up of ureteric obstruction in aorto-iliac aneurysmal disease.

Between 1979, the advent of computed tomography in our institution, and 1987 we have treated 520 aorto iliac aneurysms surgically, almost 2/3 on an elective basis, the others (183 = 35.2%) being ruptured. Among non-ruptured aneurysms 220 were symptomatic and 19 of 20 cases with ureteric entrapment occurred in these patients corresponding to 8.6% of this subgroup and verified at surgery. In all of these cases the association between ureteric obstruction and the underlying aneurysmal disease was clearly documented by computed tomography. In 8 patients ureteric entrapment was caused by an inflammatory aneurysm, in 12 cases by an arteriosclerotic aneurysm which in one case was a largely expanded internal iliac aneurysm left behind during previous surgery for a ruptured aorta aneurysm. Postoperative follow-up studies of the 8 patients with an inflammatory aneurysm revealed a time-dependent regression heading towards complete disappearance of perivascular fibrosis. Because of potential difficulties associated with the surgical treatment of inflammatory aneurysms it is important to identify perivascular fibrosis and its extent and localization pre-operatively, which can only be achieved by a CT scan. Simultaneously, CT offers information concerning the presence and degree of pyelectasis and calyceal dilatation, identifies the localisation of ureteric entrapment, defines the extent of aneurysmal disease of the iliac arteries, is best-suited for postoperative follow-up in all of the cases and has the most to offer if contrast medium investigations are contra-indicated in the presence of renal insufficiency. Probably the main reason, if not the only one for preoperative angiography, is to demonstrate associated anomalies of the visceral arteries the state of which however, can be just as well assessed by duplex sonography. Thus, computed tomography is the single most important diagnostic tool in the assessment of aorto-iliac aneurysmal disease especially when associated with ureteric entrapment.

Aged↗
PubMed1988

Two quick methods for isolation of ribulose-1,5-bisphosphate carboxylase/oxygenase.

Methods are described which allow the isolation of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (rubisco) in a very short time. Source of the material was highly impure commercial enzyme in the case of spinach rubisco or bacteria grown from a fermentor in the case of Alcaligenes eutrophus rubisco. Purity of the enzymes is demonstrated by gel electrophoreses. Enzyme isolated from fresh cells gave crystals of excellent diffraction, suitable for X-ray structure analyisis.

Alcaligenes↗
PubMed1985

Crystallization of the activated ternary complex of ribulose-1,5-bisphosphate carboxylase-oxygenase isolated from Rhodospirillum rubrum and from an Escherichia coli clone.

Ribulose-1,5-bisphosphate carboxylase-oxygenase was purified from the photosynthetic bacterium Rhodospirillum rubrum as well as from an Escherichia coli clone overproducing the enzyme. Although the latter enzyme contains 25 additional amino acid residues at the N terminus, both preparations yielded isomorphous tetragonal, bipyramidal crystals of the ternary complex of the enzyme with CO2 and Mg2+. Crystallization is sensitive to variation in pH and to the addition of the transition state analog, 2-carboxyarabinitol-1,5-bisphosphate. The systematic absences in the X-ray diffraction photographs suggest a tetragonal space group P4(3)2(1)2 or the enantiomorph P4(1)2(1)2 with cell dimensions a = b = 83 A, c = 290 A. There is one molecule per asymmetric unit. The resolution on still photographs is 3 A. The crystals are comparable to some of those already published but differ from others.

Crystallography↗
PubMed1985

Single and twinned crystals of ribulose-1,5-bisphosphate carboxylase-oxygenase from Alcaligenes eutrophus.

Ribulose-1,5-bisphosphate carboxylase-oxygenase (L8S8) from Alcaligenes eutrophus has been crystallized by equilibrium vapor diffusion techniques with ammonium sulfate as precipitant. Crystals thus obtained either as the ternary complex with CO2 and Mg2+ or as the quaternary complex with CO2, Mg2+, and 2-carboxyarabinitol 1,5-bisphosphate, a transition state analogue, diffract at least to 2.8-A resolution. Both are essentially isomorphous to each other, having orthorhombic space group C222(1) with cell dimensions a = 159 A, b = 159 A, and c = 200 A, and there is half a molecule in the asymmetric unit. The crystals of the ternary complex are sometimes twinned about the c axis so that the space group appears to be tetragonal. In this light, our earlier report (Bowien, B., Mayer, F., Spiess, E., Pähler, A., Englisch, U., and Saenger, W. (1982) Eur. J. Biochem. 106, 405-410) on a tetragonal space group P4(2)2(1)2 with crystals obtained from the same enzyme with Mg2+ and CO2 but without 2-carboxyarabinitol 1,5-bisphosphate might be incorrect.

Alcaligenes↗
PubMed1981

[Dying today].

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Attitude to Death↗
PubMed1975

Observations concerning fractures of the lateral humeral condyle in children.

From an anatomical study and clinical review of fractures of the lateral humeral condyle in children, the following conclusions are drawn. The mechanism of injury is a violent varus force with the elbow in extension, the condyle being avulsed by the lateral ligament and the extensor muscles. If the fracture is incomplete, with an intact hinge of pre-osseous cartilage medially, the fragment will not be displaced. If the fracture is complete the fragment may be displaced, and open reduction with internal fixation is mandatory. The results of open reduction more than three weeks after the fracture are no better than those of no treatment at all, and may kill the lateral condylar fragment by damaging its blood supply. The major problem of a neglected fracture is tardy ulnar nerve palsy; to avoid this, immediate anterior transposition of the nerve is recommended, operation for the fracture itself being of no benefit.

Child↗