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C Ranke

Publications and source records attributed to C Ranke.

At least 19 recordsLinked to original sources
PubMed2002

The serine proteinase thrombin promotes migration of human renal carcinoma cells by a PKA-dependent mechanism.

In this study, we demonstrated that thrombin activates protein kinase C (PKC), mitogen activated protein kinases (MAP kinases), transcription factor nuclear factor-kappa B (NF-kappa B), and cAMP-dependent protein kinase (PKA) in the human renal carcinoma cell line A-498. In addition, it enhanced the migratory capacity, but had no effect on the proliferation of A-498 cells. The effect of thrombin on migration could be blocked by the PKA inhibitor H-89 but was not influenced by inhibition of PKC, MAP kinases or NF-kappa B. We concluded, that thrombin acts as a regulator on human A-498 renal carcinoma cell migration including PKA.

Cell Division↗
PubMed2001

AV nodal pathways in the R-R interval histogram of the 24-hour monitoring ECG in patients with atrial fibrillation.

BACKGROUND: Patients with more than one AV nodal pathway show two and more peaks in the histogram of the R-R intervals of the Holter monitoring ECG during atrial fibrillation. It was the purpose of the present study to determine the number of patients showing more than one AV nodal pathway in a larger patient group with permanent atrial fibrillation by analyzing the Holter monitoring ECG. METHODS: 250 patients with permanent atrial fibrillation during Holter monitoring ECG were studied; 203 patients had structural heart disease. The number of peaks in the R-R interval histogram of each patient was determined. The distribution of the number of peaks in the R-R interval histogram in different patient groups was analyzed. RESULTS: 153 patients (61%) had one peak, 80 patients (32%) two peaks, 13 patients (5%) three peaks, and four patients (2%) four peaks, reflecting the number of different AV nodal pathways. In the different patient groups, in the patients with or without structural heart disease, with coronary heart disease, with a history of syncope, and in patients with a mean heart rate of more than 100/min, there was no significant difference in the distribution of the number of peaks in the R-R interval histogram. CONCLUSIONS: In more than one third of all patients with permanent atrial fibrillation there are two, three, or four AV nodal pathways. It is suggested that this number of different AV nodal pathways found in the studied group can be applied to all humans. 38.8% of all patients with permanent atrial fibrillation have more than one AV nodal pathway; 6.4% of all patients with atrial fibrillation would benefit from an ablation of AV nodal pathways with shorter refractory periods for reduction of the heart rate.

Adult↗
PubMed2000

[Terminating supraventricular tachycardia with adenosine--comparing the effectiveness of 12 mg and 18 mg].

OBJECTIVES: This study was done to answer the question if intravenous application of 18 mg adenosine is superior to 12 mg adenosine for the termination of supraventricular tachycardias. PATIENTS AND METHODS: 31 patients (17 men, 14 women, mean age 53 +/- 15 years [range 15-76 years]) had electrophysiological tests. In 25 patients AV nodal reentrant tachycardias were induced during programmed stimulation, 6 patients had inducible AV reentrant tachycardias with an accessory pathway. After induction of the supraventricular tachycardia (mean rate 183 +/- 29/minute, range 115-240/minute), in each patient 12 or 18 mg adenosine was applied in a bolus for terminating of the tachycardia. After the second induction of the tachycardia, a dose of 18 or 12 mg adenosine was given. The different doses of adenosine were chosen in a randomized and prospective manner in a crossover design. RESULTS: In 25 of the 31 patients (81%) the tachycardia was terminated by 12 mg adenosine. In 29 of the 31 patients (94%) the induced tachycardia was terminated by the application of 18 mg adenosine (no significant difference). In one patient, the tachycardia cessation was observed after 12 mg adenosine, but not after 18 mg adenosine. In another patient the tachycardia was not terminated by either 12 mg or by 18 mg adenosine. The termination of the tachycardia was seen after 25 +/- 8 seconds (13-51 seconds) when 12 mg adenosine was given. After the application of 18 mg adenosine the tachycardia ended after 25 +/- 8 seconds (14-44 seconds) (not significant). The asystole directly after tachycardia termination was 976 +/- 63 milliseconds (540-1700 milliseconds) with 12 mg adenosine, and 1070 +/- 628 milliseconds (530-4000 milliseconds) after the application of 18 mg adenosine (not significant). The longest asystole after termination of a tachycardia by 18 mg adenosine was 9.03 seconds. In one patient the tachycardia was reinitiated by spontaneous atrial extrasystoles after 12 mg adenosine, and reinduction of tachycardia was seen twice after 18 mg adenosine. After the administration of 18 mg adenosine, atrial fibrillation was observed in one patient. No serious complication occurred. CONCLUSIONS: In AV nodal reentrant tachycardias and AV reentrant tachycardias with an accessory pathway, which can not be terminated by the administration of adenosine in a dose of 12 mg, the tachycardia can be terminated more effectively by the application of 18 mg adenosine.

Adenosine↗
PubMed2000

Multiple AV nodal pathways with multiple peaks in the RR interval histogram of the Holter monitoring ECG during atrial fibrillation.

Two or more peaks on the 24-hour electrocardiogram (ECG) RR interval histogram of patients with atrial fibrillation suggests the presence multiple AV nodal pathways. The prevalence of multiple AV nodal pathways in this population is unknown. The study included 250 patients with permanent atrial fibrillation during 24-hour ECG. The number of peaks on the RR interval histogram was measured in each patient. A single peak was present in 153 patients (61%), 80 patients (32%) had two peaks, 13 patients (5%) had three, and 4 patients (2%) had four peaks. Among the 97 patients (39%) with > 1 AV nodal pathway, the estimated mean heart rate reduction by hypothetical ablation of all supernumerary AV nodal pathways with short refractory periods was 16 beats/min, from 82 to 65 beats/min. Among the overall population, 16 patients (6%) with > 1 AV nodal pathway had a mean heart rate > 100 beats/min. In this subgroup, modulation of AV node conduction by hypothetical ablation of all supernumerary AV nodal pathways with short refractory periods yielded an estimated reduction in mean heart rate of 26 +/- 15 beats/min, from 110 +/- 9 beats/min to 84 +/- 14 beats/min (P < 0.01), a 23% decrease. The presence of > 1 AV nodal pathway was suspected in 39% of all patients with permanent atrial fibrillation. The hypothetical ablation of all supernumerary AV nodal pathways with short refractory periods resulted in a clinically significant reduction in heart rate in 6% of patients in this population.

Aged↗
PubMed1999

[Angiology update].

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Cerebrovascular Disorders↗
PubMed1999

Standardization of carotid ultrasound: a hemodynamic method to normalize for interindividual and interequipment variability.

BACKGROUND AND PURPOSE: Accurate carotid Doppler examination is an important issue in the light of large endarterectomy trials, but recommended cutoff values for detection of >70% stenosis vary widely. Standardization of diagnostic criteria should consider patient variation and instrument variability. METHODS: We prospectively analyzed various Doppler parameters in 44 patients undergoing carotid angiography to evaluate whether normalization through individual reference measurements from the common carotid artery or the distal internal carotid artery could improve accuracy. For assessment of interindividual and interequipment variability, we performed repeated measurements of 40 carotid arteries in 21 patients. Two color-coded duplex ultrasound systems were compared for machine variability estimation: Hewlett Packard SONOS 2500 and ATL Ultramark 9 HDI. RESULTS: Intrastenotic divided by distally recorded mean blood flow velocity (mean velocity ratio) showed the closest correlation with angiography: R2=0.93. Mean velocity ratio >5 was 97% sensitive and 98% specific for detection of >70% carotid stenosis. Intrastenotic blood flow velocities were significantly different between the 2 duplex systems (0.22+/-0.16 versus 0.17+/-0. 11 m/s; P<0.001), whereas mean velocity ratio values did not differ significantly. Interobserver variation expressed as 95% CI for predicted stenosis between 2 observers was 13.6% (peak systolic velocity) and 15.4% (mean velocity ratio). CONCLUSIONS: A mean velocity ratio using distal reference measurement in the internal carotid artery can normalize for interindividual and interequipment variability.

Aged↗
PubMed1998

[Pseudoaneurysm with associated arteriovenous fistula after transfemoral puncture].

BACKGROUND: Local vascular complications after transfemoral cardiac catheterization occur with an incidence of 5%. Most commonly these lesions are pseudoaneurysms, av-fistulas, arterial dissections or direct vascular injuries. Undiagnosed vascular lesions can lead to fatal consequences especially in patients with chronic heart failure by av-fistula with significant shunt volume. CASE REPORT: We report a vascular complication of combined pseudoaneurysm and av-fistula originated from the pseudoaneurysm. The lesion was diagnosed by color Doppler ultrasound. CONCLUSION: The suspicion of a vascular lesion after vascular catheterization should immediately lead to color Doppler ultrasound. Noninvasive duplexsonography will lead to early diagnosis of vascular complications and prompt further surgical or conservative intervention with reduction of long-term sequela and morbidity.

Aged↗
PubMed1997

Blood flow velocity measurements for carotid stenosis estimation: interobserver variation and interequipment variability.

BACKGROUND: Because of the wide range of recommended threshold values for carotid stenosis graduation we performed a prospective study to determine interobserver and interequipment variability of quantitative blood flow velocity measurements. PATIENTS AND METHODS: We recorded absolute blood flow velocities and velocity ratios in 21 patients with carotid artery stenosis using two colour coded duplex ultrasound systems an ATL Ultramark 9 HDI, and a Hewlett Packard SONOS 2500 system. The ATL system was used for the interobserver variation study, where each patient was examined twice on the same day. The Doppler angle was recorded together with blood flow velocities (peak systolic velocity and mean maximum velocity from the velocity-time-integral both in the stenosis jet and 4-5 cm distally in the cranial portion of the internal carotid artery off poststenotic turbulences). RESULTS: The ATL system generated significantly higher blood flow velocity values as compared with the HP system (218 +/- 156 cm/s vs. 169 +/- 114 cm/s; p < 0.001). The Mean Velocity Ratio (the ratio of intrastenotic Vmean and poststenotic Vmean) was constant with both duplex systems. The HP system yielded 10% (Cl, 7-13%) lower predicted stenosis estimates than the ATL system with Vmax as the stenosis criterion. The stenosis estimates calculated from Mean Velocity Ratio values did not differ significantly. The 95% Cl for predicted diameter reduction between two observer was 13.6% (Vmax) and 15.4% (Mean Velocity Ratio). CONCLUSION: Because of significant interequipment differences of colour coded duplex ultrasound systems we recommend calculation of the Mean Velocity Ratio to avoid interpatient and interequipment variation of absolute flow velocities. According to our interobserver variability study, a change of more than 15% diameter reduction on follow-up examinations indicates disease progression or regression.

Aged↗
PubMed1996

[Angiology update].

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Angioplasty, Balloon↗
PubMed1995

[Angiology update].

Explore the source record for details and available documents.

Angioplasty, Balloon↗
PubMed1995

[A nomogram of duplex ultrasound quantification of peripheral arterial stenoses. Studies of the cardiovascular model and in angiography patients].

BACKGROUND AND METHODS: Blood flow velocity measurements were performed with duplex ultrasound in vitro (flow phantom) and in 62 patients who underwent angiography due to peripheral vascular disease. RESULTS: Intrastenotic peak systolic velocity (PSV) divided by proximally recorded PSV (peak velocity ratio, PVR) exhibited a strong correlation with percent diameter reduction: r2 = 0.86; N = 106 stenoses. A PVR value > or = 2.4 indicated a more than 50% stenosis with a sensitivity of 87% and a specificity of 94%. Calculation of PVR may normalize for patient variation and allow noninvasive quantification of lumen narrowing with high sensitivity and specificity. The intraobserver variability (95% CI) of stenosis quantification using PVR values was 10%. A nomogram simplifies estimation of lumen narrowing after measurement of intrastenotic and proximal PSV values. CONCLUSION: Quantification of peripheral artery stenoses can be performed easily and noninvasively with duplex ultrasound using the peak velocity ratio (PVR).

Aged↗
PubMed1994

Controlled trial of high- versus low-dose aspirin treatment after percutaneous transluminal angioplasty in patients with peripheral vascular disease.

Percutaneous transluminal angioplasty of aortoiliac and femoropopliteal atherosclerotic lesions can provide long-lasting hemodynamic improvement. High-dose aspirin is commonly prescribed as reocclusion prophylaxis, but low doses would be preferable because of fewer adverse effects. We performed a double-blind, randomized, controlled clinical trial in patients with peripheral vascular disease with lesions appropriate for angioplasty. We compared the efficacy and side effects of two doses of aspirin (50 mg vs. 900 mg daily) during a period of 12 months after angioplasty. A total of 359 patients were evaluated: 175 were randomly assigned to treatment with 900 mg aspirin daily and 184 to 50 mg aspirin daily. Thirty-nine patients developed restenosis at the angioplasty site; the cumulative percentage of event-free survival after 1 year (patency rate) was 85% in 900 mg group and 84% in 50 mg group. An equivalence test showed the two groups equivalent with respect to restenosis rates (P = 0.0003 for an equivalence region of < 10% difference. Nine patients (5%) in the 900 mg group had serious gastrointestinal side effects (peptic ulcer, 8; erosive gastritis requiring transfusion, 1) compared to two ( peptic ulcer) in the 50 mg group (P = 0.03). The results of our study show that a dose of 50 mg aspirin a day is as effective as 900 mg for the prevention of restenoses after lower limb angioplasty, and that severe gastrointestinal side effects are less frequent.

Aged↗