Search PubMed⌕ Search

Biomedical subjects

U Vogel

Publications and source records attributed to U Vogel.

At least 109 records · Page 6Linked to original sources
PubMed1992

[Infrarenal aortic aneurysm in Behçet's disease. Case report and review of the literature].

A 55-year old Turkish male was admitted with a staged aortic rupture requiring emergent surgical resection of the infrarenal aorta. Anamnesis and typical clinical findings (aphthosis, genital ulcers, pustulosis, arthritis) allowed the postoperative diagnosis of Behçet's disease. This etiologically unclear disease rarely occurs in patients from western European countries. Main symptoms are concerning the skin, the mucous membranes, and the eyes. The vascular system may occasionally be involved. In patients presenting with inflammatory arterial aneurysms, arterial or venous occlusions, careful search for the main symptoms will provide adequate diagnosis. Acute arterial affections, especially aneurysms, often urge surgical treatment. Until now, there is no effective medical prophylaxis.

Aorta, Abdominal↗
PubMed1992

[The place of thoracic plain film in the assessment of left heart insufficiency].

The chest radiographs of 24 patients with chronic left heart failure (mean duration of cardiac disease 4.3 years) were compared with the haemodynamic findings. Before the initiation of intensive medical treatment haemodynamic parameters were measured invasively and followed up for a period of up to 16 months. The heart size and roentgenographic patterns of pulmonary congestion showed a weak negative correlation with both the ejection fraction and the cardiac index. During therapy changes of cardiopulmonary haemodynamics did not correlate with alterations of the radiographic findings. Therefore chest radiographs are not useful in the assessment of the therapeutic success in long-existing left heart failure; nevertheless, they are indicated to identify secondary pulmonary disease.

Adult↗
PubMed1991

An unusual correlation between ppGpp pool size and rate of ribosome synthesis during partial pyrimidine starvation of Escherichia coli.

Escherichia coli was exposed to partial pyrimidine starvation by feeding a pyrBI strain orotate as the only pyrimidine source. Subsequently, differential rates of synthesis of rRNA and of a few ribosome-associated proteins as well as the pool sizes of nucleoside triphosphates and ppGpp were measured. As the orotate concentration in the medium was reduced, the growth rate decreased and the pools of pyrimidine nucleotides, particularly UTP, declined. We did not observe the normal inverse relation between concentration of ppGpp and growth rate; rather, we observed that the ppGpp pool was low at slow growth rates. Upshifts in growth rate were made by adding uracil to a culture growing slowly on orotate. Downshifts could be provoked by adding aspartate plus glutamate to a culture growing at a high concentration of orotate. Following the upshift, both the rates of synthesis of the ribosomal components and the pool of ppGpp increased rapidly, while they all decreased after the downshift. These results are discussed in relation to the role of ppGpp in the growth rate control and the stringent response.

Escherichia coli↗
PubMed1991

[Lumbar spinal nerve root compression syndrome as an atypical initial manifestation of a rare vascular disease].

A 55 year old male Turkish patient developed L3/L4 root compression caused by a retroperitoneal hematoma after covered perforation of the infrarenal aorta. The aneurysm was resected and a tube interposition made. For more than 20 years the patient has suffered from oral and scrotal ulcers. These signs led to the diagnosis of Behçet's disease. A review of the literature revealed 200 arterial complications (aneurysms and occlusions) in 105 patients with Behçet's disease, only 19 of them had aneurysms of the infrarenal aorta.

Aortic Rupture↗
PubMed1990

Madin-Darby canine kidney cells. I. Aldosterone-induced domes and their evaluation as a model system.

Vectorial transport of salt and water in the Madin-Darby canine kidney (MDCK) cell line is indicated by the formation of domes when a monolayer is grown on an impermeable support. We investigated aldosterone-induced dome formation and evaluated the dome as an experimental model. Transepithelial dome resistance was about 80 omega cm2 and constant when dome size exceeded 2.10(-4) cm2. The relative ion conductances (expressed as transference numbers) across the dome epithelium were tNa:tCl:tk = 0.64:0.24:0.06. They reflect the permeability properties of the paracellular shunt pathway tested at physiological concentrations of the individual ions. Aldosterone accelerated dome formation in serum-deprived MDCK monolayers. Prostaglandin E1 and transferrin were supportive but not essential for aldosterone-induced dome formation. After 72 h dome density was equal in monolayers cultured in serum-supplemented medium either in the presence or absence of mineralocorticoids. We conclude that aldosterone induces cell polarization in MDCK monolayers, leading to the formation of domes. The dome epithelium appears to be electrically isolated from the adjacent monolayer and can be studied by microelectrode techniques.

Aldosterone↗
PubMed1990

Madin-Darby canine kidney cells. II. Aldosterone stimulates Na+/H+ and Cl-/HCO3- exchange.

Experiments in dome epithelium of Madin-Darby canine kidney (MDCK) cells were performed to elucidate aldosterone action on acid-base transport. By means of pH-sensitive microelectrodes the pH of the dome fluid was measured while the apical plasma membrane was superfused. In the absence of HCO3- the dome fluid (facing the basolateral cell membrane) alkalinized in response to 10(-7) mol/l aldosterone. Amiloride (10(-3) mol/l) inhibited dome formation and pH recovery of the dome fluid from an extracellular acid load. In the presence of HCO3- dome fluid acidified in response to aldosterone. The stilbene derivative diisothiocyanate-stilbene-2,2'-disulphonic acid (DIDS) or removal of Cl- from the apical perfusate inhibited this dome acidification. In aldosterone-depleted MDCK monolayers HCO3- was actively accumulated in the dome fluid in contrast to aldosterone-supplemented cells. The results indicate that aldosterone stimulates both amiloride-sensitive Na+/H+ exchange and DIDS-sensitive Cl-/HCO3- exchange in the apical cell membrane of MDCK cells. In the absence of aldosterone the HCO3- extrusion process is localized in the basolateral membrane in series with apical Na+/H+ exchange, while in the presence of aldosterone Cl-/HCO3- is mainly localized in the apical membrane in parallel with Na+/H+ exchange. Cl- exits the cell through apical Cl- channels and is absorbed via the paracellular route.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1990

Madin-Darby canine kidney cells. III. Aldosterone stimulates an apical H+/K+ pump.

Functionally and morphologically, Madin-Darby canine kidney (MDCK) cells resemble intercalated cells of urinary epithelia. Experiments were performed on domes of confluent MDCK monolayers to test for apical H+ secretion. Apical application of 10(-3) mol/l amiloride or of Na(+)-free solution significantly reduced the limiting pH gradient across the dome epithelium (delta pHd) consistent with inhibition of apical Na+/H+ exchange. Short-circuit current (SCC) measurements disclosed an acetazolamide-sensitive, (basolateral to apical) positive transepithelial current stimulated by 10(-7) mol/l aldosterone and inhibited by acidification of apical medium to pH = 4.5. Histochemical evaluation of carbonic anhydrase (CA) activity revealed cytoplasmic and apical-membrane-bound CA particularly in dome-forming cells. Apical substitution of Na+ by K+ increased delta pHd, whereas a reduction of K+ concentration to 0.5 mmol/l or addition of barium or omeprazole (10(-5) mol/l) to the apical superfusate reduced delta pHd by at least 75%. Aldosterone-stimulated SCC was completely abolished by the apical application of barium. We conclude that besides Na+/H+ exchange MDCK cells can express an apically located H(+)-K+ pump stimulated by aldosterone and inhibited directly by the anti-ulcer agent omeprazole or indirectly, either by blocking apical K+ recycling or by interfering with the CA-dependent intracellular formation of H+ ions.

Aldosterone↗
PubMed1989

Fusion of cultured dog kidney (MDCK) cells: II. Relationship between cell pH and K+ conductance in response to aldosterone.

We have chosen the MDCK cell line to investigate aldosterone action on H+ transport and its role in regulating cell membrane K+ conductance (GKm). Cells grown in a monolayer respond to aldosterone indicated by the dose-dependent formation of domes and by the alkalinization of the dome fluid. The pH sensitivity of the plasma membrane K+ channels was tested in "giant cells" fused from individual MDCK cells. Cytoplasmic pH (pHi) and GKm were measured simultaneously while the cell interior was acidified gradually by an extracellular acid load. We found a steep sigmoidal relationship between pHi and GKm (Hill coefficient 4.4 +/- 0.4), indicating multiple H+ binding sites at a single K+ channel. Application of aldosterone increased pHi within 120 min from 7.22 +/- 0.04 to 7.45 +/- 0.02 and from 7.15 +/- 0.03 to 7.28 +/- 0.02 in the absence and presence of the CO2/HCO-3 buffer system, respectively. We conclude that the hormone-induced cytoplasmic alkalinization in the presence of CO2/HCO-3 is limited by the increased activity of a pHi-regulating HCO-3 extrusion system. Since GKm is stimulated half-maximally at the pHi of 7.18 +/- 0.04, internal H+ ions could serve as an effective intracellular signal for the regulation of transepithelial K+ flux.

Aldosterone↗
PubMed1989

[The cruciate ligament prosthesis made of polytetrafluoroethylene. 2 years' results].

The results of 142 cases, more than two years after implantation, are showed and discussed. Good results are found in 78% of the cases. Rules for the implantation are proposed. The benefits of this artificial prosthesis compared to the autologous grafts are: reduced patient morbidity, ease of implantation, immediate secure fixation, rigid immobilization not required, reduced rehabilitation time. With a new design of the device a reduced rate of ruptures is expected.

Adult↗
PubMed1981

Cytosolic and microsomal epoxide hydrolases are immunologically distinguishable from each other in the rat and mouse.

Antibodies raised to homogeneous rat liver microsomal epoxide hydrolase were used to distinguish microsomal epoxide hydrolase from epoxide hydrolase of cytosolic origin in mice and rats. Using double diffusion analysis in agarose gels, we show that anti-rat liver microsomal epoxide hydrolase forms a single precipitin line with solubilized microsomes from rat and mouse liver, but no reaction is seen with the corresponding cytosolic fractions. Rat or mouse microsomal epoxide hydrolase activity (using benzo[a]pyrene 4,5-oxide as substrate) can be completely precipitated out of solubilized preparations by the antibody, which is equipotent against rat and mouse microsomal epoxide hydrolase. No precipitation of cytosolic hydrolase activity (using trans-beta-ethyl styrene oxide as substrate) is seen with any concentration of the antibody tested. Thus, in the case of microsomal epoxide hydrolase, extensive immunological cross-reactivity exists between the two species, rat and mouse. In contrast, no cross-reactivity is detectable between cytosolic and microsomal epoxide hydrolase, even when enzymes from the same species are compared. We conclude that microsomal and cytosolic epoxide hydrolase activities represent distinct and immunologically non-cross-reactive protein species.

Animals↗
PubMedDate not supplied

The contrasting mechanisms of serum resistance of Neisseria gonorrhoeae and group B Neisseria meningitidis.

Neisseria gonorrhoeae and Neisseria meningitidis have evolved intricate mechanisms to evade complement-mediated killing. Sialylation of gonococcal lipooligosaccharide (LOS) results in conversion of previously serum sensitive strains to unstable serum resistance, which is mediated by factor H binding. Porin (Por) is also instrumental in mediating stable serum resistance in gonococci. The 5th loop of certain gonococcal PorlAs binds factor H, which efficiently inactivates C3b to iC3b. Factor H glycan residues may be essential for factor H binding to certain Por1A strains. Por1A strains can also regulate the classical pathway by binding to C4b-binding protein (C4bp) probably via the 1st loop of the Por molecule. Certain serum resistant Por1 B strains can also regulate complement by binding C4bp through a loop other than loop 1. Purified C4b can inhibit binding of C4bp to Por 1B, but not Por1A, suggesting different binding sites on C4bp for the two Por types. Unlike serum resistant gonococci, resistant meningococci have abundant C3b on their surface, which is only partially processed to iC3b. The main mechanism of complement evasion by group B meningococci is inhibition of membrane attack complex (MAC) insertion by their polysaccharide capsule. LOS structure may act in concert with capsule to prevent MAC insertion. Meningococcal strains with Class 3 Por preferentially bind factor H, suggesting Class 3 Por acts as a receptor for factor H.

Blood Bactericidal Activity↗
PubMedDate not supplied

[Percutaneous tenodesis of the Achilles tendon. A new surgical method for treatment of acute Achilles tendon rupture using percutaneous tenodesis].

APPROACH TO THE PROBLEM: Various studies (3, 6, 9, 14, 22, 28, 30, 33) have shown that, on average (26), the surgical treatment of a freshly ruptured Achilles tendon can be considered a more appropriate and better treatment than a conservative immobilisation therapy. On the other hand the rate of complications in openly executed reconstructions is quite considerable at 11-29% (13, 19, 20, 31). It therefore seems reasonable to develop a process which, by using minimal invasive measures on the tendon, reduces the risk of complications arising from surgery and simultaneously makes an early post operative treatment encouraging maximum mobility possible. METHOD: We have developed a percutaneous tenodesis of the Achilles tendon using two Lengemann extension wires and fibrin bonding at the point of rupture (8, 18). This process has been applied to 21 patients since 1995. Check-up period for further examination: 1 year. RESULTS: Exclusively male patients have been treated, average age 42 years. The Achilles tendon ruptures occurred in sporting activities and were handled with operations in an average time span of 22 hours. In one case there was a re-rupture resulting from traumatic conditions. All other results were good to very good and free of complications. CONCLUSIONS: The percutaneous tenodesis of the Achilles tendon using Lengemann extension wires and fibrin bonding provides a simple, good value and reliable process which should be used for freshly occurred Achilles tendon ruptures. CLINICAL RELEVANCE: Particularly worthy of mention are the problem-free treatment, the good results and the broad acceptance by the patients. These advantages make the demonstrated process ideal for routine clinical application.

Achilles Tendon↗