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S Kerber

Publications and source records attributed to S Kerber.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Initial experiences with dobutamine stress echocardiography in heart transplant patients].

UNLABELLED: Cardiac allograft vasculopathy (CAV) has become one of the primary obstacles to long-term survival of patients after heart transplantation. The low sensitivity of currently available noninvasive tests still remains a problem in the early diagnosis of the disease. To assess the feasibility, safety, and usefulness of dobutamine stress echocardiography as a noninvasive predictor of cardiac allograft vasculopathy, we examined 20 patients (3 female) 3-35 months after orthotopic heart transplantation. All patients underwent coronary angiography within 2 weeks of dobutamine stress echocardiography. RESULTS: 89% of the segments examined could be evaluated for wall motion abnormalities. Under increasing doses of dobutamine (5 to max. 30 micrograms/kg/min), heart rate increased from 88 +/- 13 bpm to 141 +/- 16 bpm. and systolic blood pressure from 139 +2- 14 mm Hg to 154 +/- 28 mm Hg. Two of 4 patients with angiographically detected CAV developed new wall motion abnormalities under dobutamine; their wall motion score increased from 1.23 +/- 0.22 to 1.31 +/- 0.24. In the other patients without CAV, the wall motion score remained almost unchanged (1.01 +/- 0.3 to 1.02 +/- 0.4). Dobutamine was well tolerated, and there were no serious complications. Thus, dobutamine stress echocardiography seems to be feasible and safe in patients after heart transplantation. Our results suggest that it might be useful for the detection of cardiac allograft vasculopathy. The final determination of its clinical usefulness in the diagnosis of cardiac allograft vasculopathy needs further extensive investigations.

Adult↗
PubMed1995

[In vitro validation of intravascular ultrasound, computerized and magnetic resonance tomography in diagnosis of atherosclerotic vascular segments in comparison with direct magnification radiography].

The depiction of atherosclerotic vessel abnormalities is a prerequisite for percutaneous interventional therapy and long-term observations of peripheral artery disease. The aim of this in-vitro study was to determine the potentials and limitations of 12.5 and 20 MHz intravascular ultrasound, computed tomography and magnetic resonance (MR) imaging in comparison to direct magnification radiography for the localization and quantification of peripheral vessel wall calcifications. Forty-three postmortem, human iliac segments were examined by intravascular ultrasound (12.5 and 20 MHz), computed tomography and magnetic resonance tomography (gradient echo-and spin echo-technique). For comparative analysis, each segment was divided into eight sectors of 45 degrees each; using all five methods, the presence of calcified wall areas was examined in each sector, and luminal area (42 segments) and plaque area (32 isolated plaques) were quantitatively estimated. In the sonograms, the circumferential extension of the boundary between intima and media was measured. 122 of 344 sectors showed regional vessel wall calcifications. Sensitivity of 20 MHz intravascular ultrasound was 73% versus 59% with the 12.5 probe, specificity was 97% with 20 MHz, 96% with 12.5 MHz. Sensitivity of both 12.5 and 20 MHz intravascular ultrasound was higher with increased thickness of the calcified structures. 20 MHz ultrasound identified the intima-media boundary averaging 146.8 degrees of the vessel circumference; the corresponding value of 131.8 degree with 12.5 MHz did not differ significantly. Computed tomography detected calcifications with a sensitivity of 88%, specificity was 88%. With MR imaging, sensitivity of the gradient echo-technique was 94% versus a sensitivity of 86% with spin echo-technique. Quantification of luminal and plaque areas showed that luminal area was precisely estimated only by 20 MHz ultrasound (no significant difference to direct magnification radiography), whereas all other techniques showed significant overestimation. Plaque areas were markedly overestimated by computed tomography and MR imaging, too. In an in vitro set-up, intravascular ultrasound, MR tomography and computed tomography do not allow an authentic depiction of peripheral vessel wall architecture. Limited resolution, subintimal shadowing and and distortion are the main limitations of these new techniques so that details of regional vessel wall calcifications cannot be presented thoroughly. Relevant over-estimation of luminal and plaque areas must be considered.

Arteriosclerosis↗
PubMed1995

Different effects of hypertension, atherosclerosis and hyperlipidaemia on arterial distensibility.

OBJECTIVE: To investigate the different effects of hypertension, hyperlipidaemia and atherosclerosis on the visco-elastic properties of large arteries. DESIGN: Vessel wall properties were determined in patients who had been subjected for the first time to coronary arteriography. Normotensive patients with no coronary disease (n = 15), one-vessel disease (n = 15) or two- or three-vessel disease (n = 15), 15 treated hypertensive patients (mean +/- SEM duration of hypertension 9.6 +/- 1.7 years) with no coronary disease and normocholesterolaemia and 15 healthy controls were matched for blood pressure, age and sex. METHODS: Arterial distension of the common carotid artery was determined by using a multigate Doppler system. The blood pressure curve was recorded by finger plethysmography. RESULTS: The end-diastolic diameter was significantly higher in the hypertensives (P<0.05) but not significantly different in the normotensives compared with the controls. Arterial distensibility was significantly lower in the hypertensive group [(13.3 +/- 0.8) x 10(-3)/kPa] than in the controls [(19.1 +/- 1.5) x 10(-3)/kP; P<0.01), in the group with no coronary disease [(18.8 +/- 1.3) x 10(-3)/kPa; P<0.01] and in those with one-vessel disease [(17.7 +/- 1.4) x 10(-3)/kPa; P<0.05]. Arterial distensibility was not significantly lower in the hypertensives than in the group with two- or three-vessel disease [(15.0 +/- 1.0) x 10(-3)/kPa; NS). No significant correlation was found between cholesterol or lipoprotein(a) levels and arterial distensibility in the normotensive patients. CONCLUSIONS: Hypertension is the predominant factor affecting the visco-elastic properties of large arteries. Arterial compliance is significantly altered only in extensive atherosclerosis.

Arteriosclerosis↗
PubMed1994

Characterization of atherosclerosis in a patient with familial high-density lipoprotein deficiency.

We describe the cardiovascular state of a 60-year-old homozygous patient with familial HDL deficiency (Tangier disease). The patient was examined by coronary angiography and intravascular ultrasound because of chest pain at rest and on exertion. We found a normal left ventricular function, moderately diffuse coronary sclerosis without stenosis and no critical stenosis of peripheral arteries. Intravascular ultrasound revealed the three layer appearance of arterial intima, media and adventitia with normal thickness. No calcified plaques or intimal hyperplasia could be detected apart from a single, discrete atherosclerotic lesion in one iliac artery segment. Concentric non-occlusive atherosclerotic lesions which are readily detectable with intravascular ultrasound were not found. The lack of severe atherosclerosis was remarkable insofar as massive foam cell formation and the virtually complete absence of circulating HDL is characteristic of Tangier disease and has been previously demonstrated in this patient. Our findings suggest that HDL deficiency and foam cell formation in Tangier disease are not necessarily associated with accelerated development of atherosclerosis.

Adult↗
PubMed1994

Validation of intravascular ultrasound in arteriosclerotic peripheral vessels.

In this in vitro-study, we validated intravascular ultrasound for the detection of irregular luminal contours, intraarterial structures, intimal thickening in peripheral arteriosclerotic human vessel segments and we compared sonographic criteria to the composition of arteriosclerotic lesions. Sixty-nine post-mortem segments of human peripheral arteries (6 patients) were fixed in formalin, examined with intravascular ultrasound and morphologically evaluated. Specificity, sensitivity, both positive and negative predictive value and accuracy of intravascular ultrasound for the detection of irregular luminal contours, intra-arterial structures and intimal thickening were determined for each of four quadrants. Ultrasonic features (echogeneity, homogeneity, shadowing of echoes) were also compared to the composition of lesions. Intravascular ultrasound detected regular (normal) luminal contours with a high specificity of 96.5%, a sensitivity of 65.0% and an accuracy of 88.4%. Intra-arterial structures were detected with a sensitivity of 88.6%, a specificity of 97.8% and an accuracy of 96.4%. Arteriosclerotic lesions could be localized with a sensitivity of 86.1%, a specificity of 99.1% and an accuracy of 86.9%. Intimal thickening was detectable with a sensitivity of 85.9%, a specificity of 87.8% and an accuracy of 86.2%. Meanwhile, fibrous, atheromatous and combined lesions without calcification did not show shadowing of echoes. The majority of fibrous or atheromatous lesions presented with homogeneous echoes showing hypo-, hyper- and normal density echoes. Using a 20-MHz transducer, homogeneity and echogeneity of echo patterns cannot accurately predict the different components of combined arteriosclerotic lesions.

Aorta, Abdominal↗
PubMed1994

[Significance of intravascular ultrasound in arteriosclerotic calcified intima plaques: in vitro comparison of 20 and 12.5 MHz transducers].

The aim of this in vitro study was to analyze the diagnostic performance of intravascular ultrasound (IVUS) in vessel wall calcifications and to compare the accuracy of mechanical 12.5 and 20 MHz transducers. Fourty-three sections of 10 vessels with signs of arteriosclerotic disease on pathologic examination were examined. Slices 500 microns thick were obtained and examined radiographically at 9 fold magnification. In each section, identical segments were defined, amounting to a total of 344 segments. The IVUS sections were analyzed by 3 experienced readers. For statistical evaluation ROC analysis was performed using magnification radiography as a reference. An area under the curve (AUC) of 0.79 was obtained for the 12.5 transducer and of 0.83 for the 20 MHz transducer. Additionally, sensitivity, specificity, and accuracy were determined. Sensitivity depended on the morphology, size, and density of the calcified lesions. We therefore conclude that the sensitivity of intravascular ultrasound concerning calcified arteriosclerotic plaques is limited and that there is no significant (p < 0.01) difference between mechanical 20 and 12.5 MHz transducers in examining iliac arteries.

Angiography↗
PubMed1994

In vitro correlation of intravascular ultrasound and direct magnification radiography for calcified arterial lesions.

RATIONALE AND OBJECTIVES: Intravascular ultrasound (IVUS) is an adjunct to contrast angiography that gives additional information concerning the morphology of the vascular wall. The authors examined the accuracy of intravascular ultrasound (IVUS) in the evaluation of calcified lesions within the abdominal aorta and the iliac artery. METHODS: Forty-nine human specimens (iliac artery, 26; abdominal aorta, 23) were examined using a 20-MHz 6.0-F ultrasound catheter, followed by magnification radiography of the same specimens using a newly developed microfocus x-ray tube. Magnification radiographs and ultrasound images were divided into identical sectors to analyze the morphology of calcified arteriosclerotic lesions. RESULTS: A total of 644 sectors was analyzed. Sensitivity of intravascular sonography was 70%, specificity 53%. Sensitivity strongly depended on the morphology of the calcified lesions. CONCLUSION: The detection of calcified arteriosclerotic lesions by means of IVUS revealed a sensitivity of 70% in an in vitro study using human specimens. However, the specificity of IVUS was only 53%, which is basically a random chance occurrence.

Aorta, Abdominal↗
PubMed1994

[Coronary angiography and intravascular ultrasound examination of a 60-year-old patient with familial HDL deficiency (Tangier disease)].

A 60-year-old homozygous patient with familial high density lipoprotein deficiency (Tangier disease) was examined by coronary angiography and intravascular ultrasound because of typical angina pectoris. We found a normal left ventricular function, moderately diffuse coronary sclerosis without stenosis, and no critical stenosis of peripheral arteries. Intravascular ultrasound revealed normal thickness and the three-layer appearance of the arterial intima, media, and adventitia within the peripheral arteries, and showed a single, discrete arteriosclerotic lesion in one iliac artery segment. The lack of severe atherosclerosis was remarkable insofar as massive foam cell formation in reticuloendothelial tissues and the virtually complete absence of circulating HDL is characteristic of Tangier disease and had been previously demonstrated in this patient.

Arteriosclerosis↗
PubMed1994

[Allograft vasculopathy in the early phase of orthotopic heart transplantation: angiography, intravascular ultrasound and functional in vivo findings].

Accelerated graft coronary atherosclerosis disease is the main reason for long-term mortality and morbidity of heart transplant recipients. The aim of this in vivo study was to evaluate coronary atherosclerotic vessel abnormalities and endothelial function using angiography, intravascular ultrasound, and intracoronary acetylcholine infusion. Fourteen patients (11 male, 3 female; mean age 49.3 years) were examined early after heart transplantation (mean interval after transplantation: 11 weeks) because of coronary artery disease (n = 8), idiopathic dilatative cardiomyopathy (n = 7), mitral valve replacement (n: 1) or left atrial filiae of a leiomyosarcoma (n = 1). Mean age of the donor hearts (female n = 8) was 29 years; 3 patients received double- and 14 patients triple-immunosuppression. All patients underwent biplane ventriculography and coronary angiography; a total of 120 coronary segments (main stem 21, left anterior descending artery 85, circumflex artery 14) was examined by intravascular ultrasound (20 MHz, 3.5 F catheters). In 13 patients, acetylcholine was infused into the proximal left anterior descending artery (0.15 microgram/min to 150.0 micrograms/min) to evaluate vasomotion within this segment. Ventriculography demonstrated regional wall abnormalities in 2 patients, angiography revealed 9 noncritical stenotic segments in 5 patients. Intravascular ultrasound detected 52 cross-sectional areas with a three-layer appearance indicating intimal thickening. Mean circumferential expansion of intimal proliferation was 192 degrees and mean intimal thickness was 0.35 mm. Only 5 segments of the sonographically pathological cross-sectional areas showed angiographic evidence of atherosclerotic lesions. After intracoronary infusion at a lower dose (0.15 and 1.5 micrograms/min) of acetylcholine, vasoconstriction was observed in 2 patients, at a dose of 15.0 and 150.0 micrograms/min in 10 patients. This response to acetylcholine did not depend on the intravascular or angiographical extent of atherosclerotic vessel abnormalities. In heart transplant recipients, coronary artery abnormalities can already be depicted at an early stage using intravascular ultrasound. The majority of patients show coronary vasoconstriction following infusion of acetylcholine at a higher dose. Further investigation is necessary to clarify whether the depicted vessel wall abnormalities can already be interpreted as newly developed graft atherosclerosis and whether abnormal vasomotion after acetylcholine is indicative of endothelial dysfunction.

Acetylcholine↗
PubMed1993

Early genetic amniocentesis--4 years' experience.

Four hundred and thirty early amniocenteses (EAC) from 10 to 14 weeks' gestation were compared with 300 routine amniocenteses (RAC) from 15 weeks' gestation (control A) and 733 routine amniocenteses from 16 to 18 weeks' gestation (control B) with regard to success rates, various growth parameters, and cytogenetic results. Using both in situ and trypsinization techniques, the success rate was 99.8 per cent for EAC versus 100 per cent for RAC. The average turn-around time for establishing a diagnosis was 8.4 days in EAC versus 8.3 days in 15 weeks' specimens (n.s.) and 7.7 days in 16 to 18 weeks' specimens (p < 0.0001) for the last 200 samples. The banding quality of early specimens compared favourably with that of controls (both 500-550 bphs) and was much better than that in long-term cultured chorionic villus sampling (CVS) (350-400 bphs). For level I and level II mosaicism, no statistically significant differences were noted between EAC and control group A. Comparing EAC with control group B, a significant increase in the number of numerical and structural single cell aberrations was observed (p < 0.025 and p << 0.001, respectively), whereas for multiple cell aberrations only the increase in numerical aberrations was statistically significant (p << 0.001) (chi 2-test). Clinical problems arising from the detection of mosaicism were solved in all cases by investigating parallel cultures. It is concluded that early amniocentesis is a reliable procedure which permits prenatal diagnosis of numerical and structural chromosome aberrations to a high standard.

Amniocentesis↗
PubMed1993

[Intraductal ultrasound of the pancreas--a procedure with diagnostic prospects? Initial preclinical experiences].

For the first time, human pancreas specimens (18 autopsy specimens, three resection specimens) were examined with high-resolution, flexible ultrasound catheters (20 MHz; 3.5 F, 4.8 F, 5.0 F and 6.0 F external diameters; mechanical and electronic systems). The ultrasound catheter was easily inserted into the pancreatic duct in all specimens. The sonographic tissue texture was correlated with its histological picture at defined positions. A high resolution was thus achieved in the sonomorphological differentiation of blood vessels, duct system elements, fibrotic tissue, fatty tissue and pancreas tissue with varying lipomatous composition. In a radius of an average of 5.5 mm, structures 0.1 mm large were recognised. Contrast media studies of the ductal system were carried out before and after ultrasound examination. No evidence of trauma due to catheterisation was found either with these studies or by histology. In one case, a 15 mm serous microcystic adenoma of the pancreatic head was found at intraductal examination of the resection specimen. Clinical examinations within the framework of endoscopic retrograde pancreaticography must clarify if the intraductal ultrasonography technique presented here can truly enlarge the diagnostic, repertoire used in the search of tiny focal pancreatic lesions.

Cystadenoma↗
PubMed1993

Ex vivo examination of the pancreas by intraductal ultrasonography (IDUS)

Pancreas specimens from humans (seven normal autopsy specimens, one surgical resection specimen containing a 15 mm microcystic adenoma in the pancreatic head) were examined by intraductal ultrasonography using flexible, high-resolution ultrasonic catheters (20 MHz, 4.8 and 6.0 French diameter). The catheters were easily inserted into the pancreatic duct in all specimens. The ultrasonographic tissue pattern could be correlated with the histological findings in tissue cross-sections at defined positions. A high degree of resolution was achieved in the differentiation of blood vessels, duct system elements, fibrotic tissue, fatty tissue and pancreatic tissue with a varying fat content. At an average distance of 5.5 mm, structures as small as 0.1 mm could be discriminated. No evidence of ductal trauma due to insertion of the catheters was found either on subsequent radiographic studies or on histologic examination. Clinical studies using this probe during ERCP are necessary to clarify whether intraductal ultrasonography could contribute to the diagnosis of small pancreatic lesions and to the differentiation of indeterminate ductal stenoses.

Adenoma↗
PubMed1993

Value of intravascular ultrasound in the diagnosis and characterization of patent ductus arteriosus in an adult patient.

We report the case of a 47-year-old patient with a patent ductus arteriosus who underwent angiography and percutaneous intravascular ultrasound examination. The case illustrates that intravascular ultrasound contributes to the characterization of patent ductus arteriosus when a surgical or trans-catheter closure is planned, as calcifications of the wall as well as aneurysmal dilatations can be ruled out. Furthermore, measurements of the diameter of the ductus can be made.

Diagnosis, Differential↗
PubMed1993

[Intravascular ultrasound in peripheral calcified vascular lesions: comparison with direct magnification radiography].

Intravascular ultrasound can detect calcified peripheral arteriosclerotic lesions by hyperdense echo patterns and shadowing of subintimal layers. Nevertheless, 20 MHz ultrasound systems have not been validated for the detection of peripheral calcifications; besides, it is unknown whether the depiction of calcified lesions by intravascular ultrasound depends on the morphology of the calcification. Histological evaluation of severely calcified arteries is difficult because the preparation of those specimens often causes artefacts, e.g., fracture of calcified structures. Direct magnification radiography, currently used in forensic medicine or skeleton examination, is based on a minimized focus and enables the edge-enhanced views of calcifications with high discrimination. In this in-vitro-study direct radiological magnification was used to validate intravascular ultrasound. Forty-nine segments of human peripheral arteries were fixed in formalin, examined with intravascular ultrasound and, as a reference, radiographically magnified using a newly developed microfocus x-ray tube. Sensitivity, specificity, positive and negative predictive value, and accuracy of intravascular ultrasound for the detection of calcified wall areas were determined and compared to the appearance (configuration, circumferential and areal expansion, density, number of fragments) of these calcifications. Thicknesses of 110 single calcified structures were estimated on sonograms and radiograms. The overall sensitivity of the 20 MHz intravascular ultrasound system for the detection of calcification in 913 sectors was 70%, specificity 53%, positive predictive value 66%, negative value 58% and accuracy 62%. The depiction of calcified regions by direct magnification radiography showed that the sensitivity strongly depended on the density of the calcification. Sensitivity was 81% with calcified lesions of high density, but only 51% with lesions of low density.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1993

[Diagnostic value of intravascular ultrasound diagnosis in peripheral arteriosclerotic blood vessel changes].

Intravascular ultrasound is an adjunct for the diagnosis of atherosclerotic peripheral vessels. In this in-vitro study, 69 segments of human peripheral arteries were fixed in formalin, examined with intravascular ultrasound and pathomorphologically evaluated. Sensitivity, specificity, both positive and negative predictive value and accuracy of intravascular ultrasound for the detection of irregular lumen contours, intraarterial structures and intimal thickening were determined for each of four quadrants. Sonographic features (echogeneity, homogeneity, shadowing of echoes) were compared to the architecture of lesions. Intravascular ultrasound detected regular (normal) lumen contours with high specificity (96.5%), a sensitivity of 65.0%, and an accuracy of 88.4%; intraluminal structures were detected with a sensitivity of 88.6%, a specificity of 97.8%, and an accuracy of 96.4%. Most atherosclerotic lesions could be localized with a sensitivity of 86.1%, a specificity of 99.1%, and an accuracy of 86.9%. Slight intimal thickening was detectable with a sensitivity of 85.9%, a specificity of 87.8%, and an accuracy of 86.2%. Comparison of sonographic features and the pathomorphological architecture of atherosclerotic lesions revealed that fibrous, atheromatous, and complex lesions without calcification did not show shadowing of echoes. The majority of fibrous or atheromatous lesions presented with homogeneous echoes; these lesions showed hypo-, hyper- and normodense echoes. The homogeneity of echoes did not help to identify the different components of combined atherosclerotic lesions. Thus, intravascular ultrasound is able to detect irregular lumen contours, intraluminal structures, and intimal thickening, but further sonographic criteria are needed to identify the architectural structure of combined lesions.

Aorta, Abdominal↗
PubMed1993

[Detection of pacemaker electrode infection using intravascular ultrasound].

The case of a 60-year-old man who developed fever 14 months after last implantation of a DDD pacemaker system is reported. Though staphylococcus epidermidis could be identified in several blood cultures, transthoracic and transesophageal echocardiograms and scintigraphy with antibodies to human leucocytes could not identify any focus of infection. The percutaneous intravascular and intracavitary ultrasound examination clearly demonstrated a vegetation within the subclavian vein, being attached to the ventricular lead; within that segment of the vein the atrial lead showed a small hyperdense structure. Further vegetations along the leads within the right atrium and ventricle could be ruled out. Subsequent removal of the pacemaker system caused resolution of the signs of inflammation.

Anti-Bacterial Agents↗
PubMed1992

Mosaicism in 45,X Turner syndrome: does survival in early pregnancy depend on the presence of two sex chromosomes?

Cytogenetic and molecular genetic findings in 91 patients with Turner syndrome are reported. In 87 patients, chromosome studies were carried out both in lymphocyte and fibroblast cultures. Mosaicism was demonstrated in 58 of these patients (66.7%), whereas only 18 (20.7%) were apparent non-mosaic 45,X, and 11 patients (12.6%) showed non-mosaic structural aberrations of the X chromosome. Among the mosaic cases 16 (18.4% of all patients) displayed a second cell line containing small marker chromosomes. The association of Y-specific chromosomal material with the presence of marker chromosomes was demonstrated in 6 out of 7 mixoploid fibroblast cell lines by polymerase chain reaction amplification and by Southern-blot analysis. The observation of ring formation and morphological variability in vivo and in vitro, and the continuous reduction in the percentage of cells containing marker chromosomes in longterm cultivation experiments indicated an increased instability of marker chromosomes. The findings suggest that in vivo selection of structurally altered sex chromosomes exists. Thus, the observation of apparent non-mosaic 45,X chromosomal complements in liveborn individuals with Turner syndrome does not contradict the hypothesis that some degree of mosaicism is necessary for survival in early pregnancy.

Blotting, Southern↗