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Biomedical subjects

Michael Uder

Publications and source records attributed to Michael Uder.

8 recordsLinked to original sources
PubMed2003

Angiography for acute lower gastrointestinal hemorrhage: efficacy of cut film compared with digital subtraction techniques.

PURPOSE: To find out if digital subtraction angiography (DSA) has a different diagnostic power than conventional cut-film angiography in investigating acute lower gastrointestinal (GI) hemorrhage. MATERIALS AND METHODS: Retrospective analysis of two cohorts of patients investigated by angiography for acute lower GI hemorrhage was performed. One group of patients treated at one center ("hospital H") underwent conventional angiography. The other patients, treated at another center ("hospital G"), were investigated exclusively by DSA. The groups were compared for demographic characteristics, etiology, and bleeding parameters. The diagnostic power of both angiographic modalities was compared and statistically analyzed. RESULTS: Fifty-five lower GI hemorrhages investigated by conventional cut-film angiography and 53 cases studied by DSA were included. Both study groups had statistically similar demographic and bleeding characteristics. Overall sensitivity, specificity, and positive and negative predictive values of cut-film angiography for localizing the lower GI bleeding were 62%, 73%, 86%, and 42%, whereas, for DSA, the respective values were 60%, 100%, 100%, and 24% (Z-test P values were.78,.02,.03, and.16). CONCLUSIONS: DSA is as sensitive as conventional cut-film angiography for localizing acute lower GI bleeding. If a lesion is found, the chance that it will be the bleeding source is higher with DSA than with conventional angiography.

Acute Disease↗
PubMed2003

Early posttransplantation renal allograft perfusion failure due to dissection: diagnosis and interventional treatment.

OBJECTIVE: The aim of our study was to describe the role of interventional radiology, especially in the use of vascular stents, in early renal perfusion failure after transplantation. CONCLUSION: Angiography revealed intimal dissection of the graft artery and graft venous thrombosis, which were successfully treated with stent angioplasty and thromboaspiration. For early vascular complication after transplantation, timely use of angiography and subsequent intervention should be recognized as potentially effective and safe treatment techniques.

Aged↗
PubMed2002

Successful conservative treatment of infected penile prostheses [correction of protheses].

Three patients with postoperative purulent penile prosthesis infection were successfully treated without explantation by employing a conservative treatment strategy of local and systemic application of clindamycin. Should no evidence of systemic infection be obvious, a conservative "local rescue" procedure should be initiated before resorting to surgical explantation.

Administration, Oral↗
PubMed2002

cAMP and cGMP do not mediate the vasorelaxation induced by iodinated radiographic contrast media in isolated swine renal arteries.

PURPOSE: Vasodilatation is a frequent side effect of radiographic contrast media, partially due to a direct effect on vascular smooth muscles. Our purpose was therefore to examine any possible implication of the cyclic adenosine monophospate (cAMP) and cyclic guanosine monophosphate (cGMP) pathways in contrast media induced vasorelaxation. MATERIAL AND METHODS: Isolated segments of swine renal arteries were precontracted with 10 microM phenylephrine and relaxed with iomeprol before and after blockade of the cAMP and cGMP pathways. RESULTS: 80 mM and 160 mM of iomeprol significantly relaxed about 52% and 68% of the precontracted arterial rings, respectively. 10 microM of IBMX, a phosphodiesterase inhibitor, did not increase the relaxant effect of 80 mM iomeprol but increased the relaxations induced by 400 nM forskolin by about 1.9 times (which stimulates the production of cAMP), and by 1 microM sodium nitroprusside (which stimulates the production of cGMP). 1 microM of H89 (an inhibitor of the cAMP-dependent protein kinase), was able to reduce the relaxation induced by 4 microM forskolin by about 2.5 times but had no significant effect on the relaxation induced by 160 mM iomeprol. 10 microM of ODQ (an inhibitor of the soluble guanylate cyclase), could reduce the relaxation induced by 10 microM of SNP but not the one induced by 160 mM iomeprol. Moreover, the absence of endothelial cells did not alter the relaxation induced by iomeprol. CONCLUSION: The activation of the cAMP and cGMP pathways are not involved in the in vitro relaxation induced by iomeprol in swine renal arteries.

Animals↗
PubMed2002

Nonionic contrast media iohexol and iomeprol decrease renal arterial tone: comparative studies on human and porcine isolated vascular segments.

RATIONALE AND OBJECTIVES: The vasoconstriction of the renal arteries is frequently considered as a crucial factor for radiocontrast-induced nephropathy. A direct effect of iodinated radiographic contrast medium (RCM) on vascular smooth muscle is supposed to be one component of the vascular response. We studied the effect of the nonionic RCM iomeprol and iohexol on the tonus of isolated human and porcine renal arteries in vitro. METHODS: In an organ bath renal arterial rings, uncontracted or precontracted by 10 micromol/L phenylephrine were incubated with increasing concentrations (15-103 mg iodine/mL) of iohexol, iomeprol, and mannitol solution isoosmolar to the contrast media. In a part of the preparations the endothelium was destroyed. Human vessels were obtained from tumor nephrectomy specimens of 10 patients. RESULTS: In human experiments iomeprol and iohexol (P < 0.05) relaxed renal arterial rings whereas mannitol produced concentration-dependent contractions. The relaxation by both contrast media was slightly attenuated upon increasing their concentration. The differences between mannitol solutions and RCM were statistically significant (P < 0.001) at concentrations of 57 mg iodine/mL and higher. Precontracted rings were significantly stronger relaxed by the RCM compared with mannitol (P < 0.001). The contrast medium induced relaxation did not depend on the presence of an intact endothelium (P > 0.05). Experiments with renal arterial segments prepared from swine showed similar results, with stronger relaxations than the human preparations. CONCLUSION: Iomeprol and iohexol relaxed isolated renal arterial segments. These observations are in contradiction with the hypothesis that contrast media induce nephropathy by a direct vasoconstrictive effect on vascular smooth muscle. They do not exclude, however, a reduction of renal blood flow by other factors like liberation of hormones.

Animals↗
PubMed2001

MRI of penile fracture: diagnosis and therapeutic follow-up.

A rupture of corpus cavernosum (CC) is a rare injury of the erect penis. The present study describes the role of MRI for diagnosis and follow-up of this injury. Four patients with clinically suspected acute penile fractures underwent MRI. Imaging findings were confirmed at surgery. In three patients, follow-up MRI was also available at 1, 6 and 16 weeks after surgical repair. In all patients pre-contrast T1-weighted images (T1WI) clearly disclosed ruptures of CC, which depicted as discontinuity of low signal intensity of the tunica albuginea (TA). Concomitant subcutaneous haematoma were well visualised both on T1-weighted (T1WI) and T2-weighted images, whereas haematoma in CC were optimally demonstrated on contrast-enhanced T1WI. On follow-up MRI all fractures presented similar healing process. Shortly after the repair, the tunical suture showed an increase in signal intensity on pre-contrast T1WI and was strongly enhanced with the administration of contrast material. Then the tear site gradually recovered low signal intensity on all spin-echo sequences by 4 months after surgery. These serial findings may suggest the formation of vascularised granulation tissue during cicatrisation. Magnetic resonance imaging is of great value for the diagnosis and follow-up in patients with penile fracture.

Adult↗