Biomedical subjects

R Jakob

Publications and source records attributed to R Jakob.

7 recordsLinked to original sources

PubMed1992

Technique and results of vascular endoscopy in arterial and venous reconstructions.

In an effort to maximize results, vascular endoscopy was used in our institution to monitor arterial and venous reconstructions. Since 1982, angioscopy was applied as a control method in 182 venous thrombectomies to treat iliofemoral thrombosis and 114 aortoiliac thromboendarterectomies. Of the cases with venous thrombectomy reviewed, 50% were incomplete by endoscopic evidence; of these, in 80% the remaining clots could be partly or completely removed. Additionally, in six patients a venous spur was found. Of 114 attempted aortoiliac thromboendarterectomies, only 91 could be completed. In the remainder, endoscopic evidence of persistent intimal flaps forced us to bypass the affected segments. With further miniaturization of the angioscopes, the method was also applied to check vessel repair on small-caliber arteries. In an initial study with 220 femorodistal bypasses we were unable to find a statistically significant difference of primary patency in grafts that were endoscopically controlled or not. In the learning phase with the in situ technique, we identified competent valve remnants in 40%, but this rate could be reduced to 12.7% with growing experience in valvulotomy. We conclude from our data that angioscopy is very helpful in assessing the morphological integrity of aortoiliac thromboendarterectomies and venous thrombectomies. The actual value in infrainguinal arterial reconstructions still remains to be proven.

Angioscopy↗

PubMed1992

Purifying nuclei.

Nuclear isolation methods exist since over 50 years and even today new procedures and amendments of standard methods are published. They can be classified into nonaqueous and aqueous methods. The latter can be subdivided into isotonic, hypertonic and hypotonic systems. In most cases the aqueous isolation renders nuclei closer to their physiological status in the cell. A standard method for the hypotonic isolation of nuclei is presented and the methodology of nuclear isolation is discussed.

Aedes↗

PubMed1990

Karyophilic properties of Semliki Forest virus nucleocapsid protein.

Semliki Forest virus capsid (C) protein molecules (Mr, 33,000) can be introduced efficiently into the cytoplasm of various target cells by electroporation, liposome, and erythrocyte ghost-mediated delivery (M. Elgizoli, Y. Dai, C. Kempf, H. Koblet, and M.R. Michel, J. Virol. 63:2921-2928, 1989). Here, we show that the transferred C protein molecules partition rapidly from the cytosolic compartment into the nucleus. Transport of the C protein molecules into the nucleus was reversibly arrested by metabolic inhibitors, indicating that the transfer process is energy dependent. Fractionation of isolated nuclei revealed that the delivered C protein preferentially associates with the nucleoli. This finding was confirmed by morphological studies, showing that in an in vitro system containing ATP isolated nuclei rapidly accumulated rhodamine-labeled C protein in their nucleoli. Furthermore, in this assay system, the lectin wheat germ agglutinin prevented transfer of C protein through nuclear pores. These results are in agreement with our observation that nucleoli contain measurable amounts of newly synthesized C protein as early as 5 h after infection of cells with SFV. Thereafter, nucleolar-associated C protein increased progressively during the course of infection.

Adenosine Triphosphate↗

PubMed1990

[An automated in vitro toxicity test of 25 chemicals].

A computer controlled bench-top analyser was used to establish an automated in vitro-cytotoxicity test. It is based on the continuous monitoring of growth of Salmonella typhimurium TA 98 and TA 100 (strains that are also employed in the classical Ames test (1) for mutagenicity screening) under the influence of the toxic compounds. With this method we can quantify general cytotoxicity and in addition, some questions concerning the mechanism of the toxic influence on the test organisms can be answered. Its simplicity and reliability as well as the good correlation with in vivo data make the new test system suitable for pre-screening the toxicity of a large number of compounds within short time.

Biological Assay↗

PubMed1989

Automated turbidimetry for the rapid differentiation and enumeration of bacteria in food.

A fully automated analysis system has been used to determine bacterial contamination in food, both qualitatively and quantitatively. Growth curves of bacterial flora were monitored using differential media, and a correlation was established between growth curve parameters and colony-forming units derived from drop-plating as the reference method. Optimal correlation was reached by multiple linear regression. The results were already obtained 16 h.

Animals↗

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↗

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↗