Biomedical subjects

Hanns Ackermann

Publications and source records attributed to Hanns Ackermann.

At least 19 recordsLinked to original sources

PubMed2007

Radiation therapy for painful heel spurs: results of a prospective randomized study.

PURPOSE: To evaluate the efficacy of two different dose-fractionation schedules for radiation therapy (RT) in patients with painful heel spurs. PATIENTS AND METHODS: 130 patients were randomized into two groups: the low-dose (LD) group (n = 65 heels) received a total dose of 3.0 Gy given in two weekly fractions of 0.5 Gy; in the high-dose (HD) group (n = 65 heels), two weekly fractions of 1.0 Gy were applied over 3 weeks (total dose 6.0 Gy). In 24 sites of the HD group and 17 sites of the LD group, a second RT course was given. The results were assessed using a five-level function score which was documented before RT, at the end of each RT course, and at 6 weeks and 6 months thereafter. RESULTS: At 6-month follow-up, RT led to a highly significant reduction of symptoms in both groups. In the HD group, 31 sites were classified as excellent (score: 90-100), 13 as good (score: 70-85), twelve as moderate (score: 45-65), and nine as poor (score: 0-40). In the LD group, 35 sites were classified as excellent, eight as good, ten as moderate, and twelve as poor. The comparison of the difference of the sum score and the single criteria before RT and at 6 months after RT using the Wilcoxon-Mann-Whitney U-test revealed no statistically significant difference of response to RT between both groups. CONCLUSION: RT is an effective treatment option for the management of inflammatory heel spurs. The dose for an RT course should not exceed 3.0 Gy.

Adult↗

PubMed2006

Prevalence and clinical significance of Staphylococcus aureus small-colony variants in cystic fibrosis lung disease.

Small-colony variants (SCVs) of Staphylococcus aureus can be isolated from the chronically infected airways of patients suffering from cystic fibrosis (CF). These slow-growing morphological variants have been associated with persistent and antibiotic-resistant infections, such as osteomyelitis and device-related infections, but no information is available to date regarding the clinical significance of this special phenotype in CF lung disease. We therefore investigated the prevalence of S. aureus SCVs in CF lung disease in a 12-month prospective study and correlated the microbiological culture results with the patients' clinical data. A total of 252 patients were screened for the presence of SCVs. The prevalence rate was determined to be 17% (95% confidence interval, 10 to 25%) among S. aureus carriers. S. aureus isolates with the SCV phenotype showed significantly higher antibiotic resistance rates than those with the normal phenotype. Patients positive for SCVs were significantly older (P = 0.0099), more commonly cocolonized with Pseudomonas aeruginosa (P = 0.0454), and showed signs of more advanced disease, such as lower forced expiratory volume in 1 s (P = 0.0148) than patients harboring S. aureus with a solely normal phenotype. The logistic regression model determined lower weight (P = 0.016), advanced age (P = 0.000), and prior use of trimethoprim-sulfamethoxazole (P = 0.002) as independent risk factors for S. aureus SCV positivity. The clinical status of CF patients is known to be affected by multiple parameters. Nonetheless, the independent risk factors determined here point to the impact of S. aureus SCVs on chronic and persistent infections in advanced CF lung disease.

Adolescent↗

PubMed2006

Facilitating coronary artery evaluation in MDCT using a 3D automatic vessel segmentation tool.

The purpose of this study was to investigate a 3D coronary artery segmentation algorithm using 16-row MDCT data sets. Fifty patients underwent cardiac CT (Sensation 16, Siemens) and coronary angiography. Automatic and manual detection of coronary artery stenosis was performed. A 3D coronary artery segmentation algorithm (Fraunhofer Institute for Computer Graphics, Darmstadt) was used for automatic evaluation. All significant stenoses (>50%) in vessels >1.5 mm in diameter were protocoled. Each detection tool was used by one reader who was blinded to the results of the other detection method and the results of coronary angiography. Sensitivity and specificity were determined for automatic and manual detection as well as was the time for both CT-based evaluation methods. The overall sensitivity and specificity of the automatic and manual approach were 93.1 vs. 95.83% and 86.1 vs. 81.9%. The time required for automatic evaluation was significantly shorter than with the manual approach, i.e., 246.04+/-43.17 s for the automatic approach and 526.88+/-45.71 s for the manual approach (P<0.0001). In 94% of the coronary artery branches, automatic detection required less time than the manual approach. Automatic coronary vessel evaluation is feasible. It reduces the time required for cardiac CT evaluation with similar sensitivity and specificity as well as facilitates the evaluation of MDCT coronary angiography in a standardized fashion.

Aged↗

PubMed2006

[Functional outcome after megavoltage irradiation for heel spurs].

PURPOSE: To evaluate results on the functional outcome and to determine prognostic factors and long-term response to low-dose megavoltage irradiation. PATIENTS AND METHODS: A total dose of 6.0 Gy given in two weekly fractions of 1.0 Gy was applied to 305 sites (252 patients). After 6 weeks, 97 sites (31.8%) received a second radiotherapy (RT) course. Assessment system was a function score which was documented before RT, at the end of each RT course, and at 6 weeks and 6 months after treatment. After an observation period of >/= 24 months, a follow-up examination was attempted to evaluate the late response. RESULTS: At 6-month follow-up, 85.6% responded with a score improvement. The outcome was excellent (score: 90-100) in 135/305 sites (44.3%), good (score: 70-85) in 60/305 sites (19.7%), moderate (score: 45-65) in 63/305 (20.7%) sites, and poor (score: 0-40) in 47/305 sites (15.4%). 231/305 sites (75.7%) had no or mild pain. 296/305 (97,0%) had no or only slight limitations in work and 253/305 (82,9%) in daily activities. 255/305 (83,6%) had no or slight discomfort in gait. The long-term follow-up after a mean observation period of 48.4 months revealed 15 recurrences (7.3%). The patients' age, sex, and the duration of symptoms before initiation of RT (</= 6 months vs. > 6 months) did not prove to be prognostic factors. No early or late toxicity related to the use of RT was detected. CONCLUSION: Megavoltage 6-MV photon-beam irradiation is a safe, effective and long-acting treatment modality in the management of heel spur patients. The function score has been proven to be a feasible method in clinical practice for evaluation of treatment outcome.

Activities of Daily Living↗

PubMed2006

[Risk factors for suicide in substance-related disorders].

OBJECTIVE: To assess the contribution of sociodemographic and psychopathologic predictors for suicide in alcohol-related disorders and in substance-related disorders in general and to examine the constellations of risk factors for suicide. METHODS: Out of 163 suicides (using psychological autopsy method) and 396 population-based control persons, 67 suicides and 67 controls with substance-related disorders (DSM-IV; alcohol-related disorders: suicides: n = 36, controls: n = 27) were assessed. RESULTS: Affective disorders, suffering from substance dependence, and low education independently predicted increased suicide risk in alcohol-related disorders as well as in substance-related disorders in general, severe nicotine consumption only in alcohol-related disorders. CONCLUSIONS: There are common risk factors for suicide in alcoholism and substance-related disorders in general. Effective suicide prevention strategies must include a focus on substance dependence as well as on affective disorders.

Adult↗

PubMed2006

Navigation-based needle puncture of a cadaver using a hybrid tracking navigational system.

PURPOSE: The purpose of this study was to determine the puncture accuracy of a navigational system, Medarpa, in a soft tissue environment using augmented overlay imaging. MATERIALS AND METHODS: Medarpa is an optical electromagnetic tracking system, which allows tracking of instruments, the radiologist's head position, and the transparent display. The display superimposes a computed tomography scan of a cadaver chest on a human cadaver in real time. In group A, needle puncture was performed using the Medarpa system. Three targets located inside the cadaver chest were selected. In group B, the same targets were used to perform standard computed tomography-guided puncture using a single-slice technique. A total of 42 punctures were performed in each group. Postpuncture computed tomography scans were made to verify needle tip positions. RESULTS: Mean deviation from targets was 8.42 mm +/- 1.78 mm for group A and 8.90 mm +/- 1.71 mm for group B. No significant difference was found between group A and B in any target (P > 0.05). No significant difference was found between the targets of the same group (P > 0.05). Procedural time for 42 punctures was 160 minutes in group A versus 289 minutes in group B (P < 0.05). CONCLUSION: Needle puncture in a soft tissue environment using the navigational system Medarpa can be reliably performed and matches the accuracy achieved by a computed tomography-guided puncture technique.

Biopsy, Needle↗

PubMed2006

Multi-detector row CT coronary angiography: influence of reconstruction technique and heart rate on image quality.

PURPOSE: To prospectively evaluate to what extent image quality in 16-detector row computed tomographic (CT) coronary angiography is a function of the heart rate and the image reconstruction technique used. MATERIALS AND METHODS: A total of 70 patients (49 men, 21 women; mean age, 59.1 years +/- 5.8 [standard deviation]) consecutively underwent multi-detector row CT coronary angiography; 49 patients additionally underwent coronary angiography. Image reconstruction was based on both relative and absolute timing. A total of 20 equidistant relative and absolute image reconstructed intervals were assessed by applying a four-step grading scale. Cluster and discrimination analysis, Spearman correlation analysis, and Wilcoxon and chi2 tests were used for statistical analysis. Institutional review board approval and written informed consent were obtained. RESULTS: Though significantly (P < .001) better image quality was observed for image reconstruction based on absolute timing and in patients with lower heart rates, influence on diagnostic accuracy was not significant. Irrespective of the reconstruction technique used, best image quality was observed in patients with a low heart rate for middiastolic reconstruction intervals (starting points: 61% of R-R interval [range, 40%-75%] and 599.3 msec after R [range, 450-840 msec]) and in patients with a high heart rate for end-systolic or early-diastolic intervals (starting points: 27.3% of R-R interval [range, 10%-45%] and 202.3 msec after R [range, 82-336 msec]). With regard to the vessel section and reconstruction technique, cutoff heart rates of the intervals were 64.0-68.5 beats per minute. Patients with stenoses of more than 50% were identified with 86% sensitivity and specificity, and there was no significant difference between relative and absolute timing (P = .99). CONCLUSION: In multi-detector row CT coronary angiography, image quality depends on the choice of a suited reconstruction interval. In patients with high heart rates, the best image quality can be obtained with end-systolic and early-diastolic intervals; in patients with low heart rates, the best results are achieved with middiastolic intervals.

Adult↗

PubMed2005

Peripheral artery stent visualization and in-stent stenosis analysis in 16-row computed tomography: an in-vitro evaluation.

The accuracy of 16-row multidetector CT in the visualization of different peripheral artery stents and in the appraisal of in-stent stenosis was assessed. Nine different stent types (nitinol and stainless steel) with three diameters (6, 8 and 10 mm) were used; altogether 27 stents were analyzed in a barrel-shaped vascular model. Low-grade (<40%) and high-grade (>60%) in-stent stenoses were simulated by polyurethane sticks (70 HU) of differing diameters (2-6 mm). Imaging was performed with 16x0.75-mm detector collimation, 130 mAs, 120 kV, 12-mm table feed/rotation, 1.0-mm slice thickness and 0.5-mm increment. The stent diameter, strut thickness, in-stent attenuation values, degree and degree of in-stent stenosis were evaluated. Nitinol stents showed significantly (P<10-6) less stent lumen narrowing, artificial strut thickening and overestimation of the degree of in-stent stenoses than stainless steel stents. In-stent attenuation values and artificial strut thickening were significantly (P<10-6) lower in 10- and 8-mm stents than in 6-mm stents. Stent lumen narrowing was significantly less in 10-mm stents than in 8-mm (P<10-4) or 6-mm (P<10-6) stents. In-stent stenoses were significantly overestimated, irrespective of the stent diameter. In 6-mm stents overestimation was significantly higher than in 8-mm (P<0.01) or 10-mm stents (P<10-6). Under in-vitro conditions 16-row MDCT allowed an accurate identification of in-stent stenosis, but significantly overestimated the effective degree of the stenosis.

Constriction, Pathologic↗

PubMed2005

Prediction of acute renal allograft rejection by urinary monokine induced by IFN-gamma (MIG).

Early diagnosis of acute allograft rejection (AR) is still decisive for long-term renal allograft survival. The aim of this study was to define the role of the chemokine monokine induced by IFN-gamma (MIG) (CXCL9) and IFN-gamma-inducible protein 10 (IP-10) (CXCL10) as early markers of AR in renal transplantation (NTX). In a prospective study, 69 de novo renal transplant recipients were monitored and urine samples were collected after NTX for a median of 29 d. In pH-adjusted urine, MIG and IP-10 were determined by modified ELISA. AR was clinically diagnosed in 15 of 69 recipients and confirmed by biopsy in 14 of 15 AR patients (Banff classification). Corresponding to CXCR3-positive infiltrates in renal tissue, urinary MIG was elevated in 14 of 15 AR patients with a median of 2809 pg/ml (quartile 25% and 75% = 870 and 13,000; n = 15), being significantly (P < 0.0001) different from both nonrejecting allograft patients (NO-AR) (median, 25%, and 75%: 96, 1.0, and 161, n = 54) and healthy controls (median, 25%, and 75%: 144, 19, and 208, n = 13). Urinary MIG predicted AR with a sensitivity of 93% and a specificity of 89%. In AR and NO-AR groups, MIG values correlated well with IP-10 (P < 0.001). MIG values indicated both imminent rejection and response to successful antirejection therapy. MIG was not related to intercurrent infections or other causes for impairment of renal function. In a multivariate analysis, MIG correlated best (P < 0.001) with AR from all AR-associated parameters. In conclusion, urinary MIG serves as a very sensitive and specific predictor for AR, mirrors response to antirejection therapy, and thus may contribute to improved long-term renal allograft survival.

Acute Disease↗

PubMed2005

Quantitative cartilage volume measurement using MRI: comparison of different evaluation techniques.

This study was aimed to investigate the accuracy and time saving of MRI Argus application in the assessment of cartilage volume in osteoarthritic knees. Twelve knees of patients suffering from osteoarthritis were scanned with a 1.5 T MRI using a 3D gradient echo sequence with selective water excitation. Cartilage volume of the tibial and patellar compartment was determined with a validated multiprocessing computer system (Octane Duo, Silicon Graphics, Mountain View, Calif., USA). The calculated cartilage volumes were compared to the results acquired by the Argus (Siemens Inc., Erlangen, Germany) application software using the MRI data sets. Compared to the multiprocessing computer system a time saving of at least 30 min for cartilage volume determination was achieved. The mean differences of Argus versus the multiprocessing computer system were 4.26+/-0.84 and 7.80+/-0.87% for the medial and lateral tibial plateau and 5.94+/-0.59% for the patella (no statistical significant difference; P>0.05). The applied Argus software can be used for fast and accurate determination of cartilage volume in the knee joint.

Aged↗

PubMed2005

Multislice CT of the pelvis: dose reduction with regard to image quality using 16-row CT.

To optimize examination protocols of 16-row multi-detector CT (MDCT) of pelvis for dose reduction with regard to image quality. MDCT of pelvis was performed on 12 cadaver specimens with stepwise reduction of tube current from 160 mA (113, 80, 56, 40, 28) to 20 mA at 120 kV. Scan parameters were 16 x 1.5 mm collimation. Reconstructions of axial and coronal images were used for evaluation of cortex, trabeculum, image quality, image noise, acetabulum and iliosacral (ISJ) joints. After data were blinded, evaluation of images was done by three radiologists according to 5-point Likert scale. Accuracy of the observers in sorting films according to dose reduction was determined with kappa coefficient. Mean values of image evaluation were determined. Pronounced deterioration of image quality for all criteria was observed between 80 and 28 mA. Adequate image quality was obtained at 40 mA [effective dose (E): 2.2 mSv, CTDI(w): 2.8 mGy] for criterion detailed definition of acetabulum and ISJ and at 80 mA (E: 4.4 mSv, CTDI(w): 5.6 mGy) for remaining criteria. Moderate agreement was observed between the three observers (kappa coefficient: 0.31). All observers were excellent in arranging images according to decreasing dose. Using 16-row MDCT image quality of pelvis is acceptable at 80 mA and 120 kV. This translates into a dose reduction of 33% of average value of the nationwide survey of the German Roentgen Society (1999) for this type of examination.

Acetabulum↗

PubMed2005

ABCB1 genotype of the donor but not of the recipient is a major risk factor for cyclosporine-related nephrotoxicity after renal transplantation.

Cyclosporine (CsA) nephrotoxicity is a severe complication in organ transplantation because it leads to impaired renal function and chronic allograft nephropathy, which is a major predictor of graft loss. Animal models and in vivo studies indicate that the transmembrane efflux pump P-glycoprotein contributes substantially to CsA nephrotoxicity. It was hypothesized that the TT genotype at the ABCB1 3435C-->T polymorphism, which is associated with decreased expression of P-glycoprotein in renal tissue, is a risk factor for developing CsA nephrotoxicity. In a case-control study, 18 of 97 patients developed CsA nephrotoxicity and showed complete recovery of renal function in all cases when switched to a calcineurin inhibitor-free regimen. Both recipients and donors were genotyped for ABCB1 polymorphisms at the positions 3435C-->T and 2677G-->T/A. For controlling for population stratification, two additional polymorphisms, CYP2D6*4 and CYP3A5*3, with intermediate allelic frequencies were studied. The P-glycoprotein low expressor genotype 3435TT only of renal organ donors but not of the recipients was overrepresented in patients with CsA nephrotoxicity as compared with patients without toxicity (chi2 = 10.5; P = 0.005). CsA dosage, trough levels, and the concentration per dose ratio were not different between the patient groups. In a multivariate model that included several other nongenetic covariates, only the donor's ABCB1 3435TT genotype was strongly associated with CsA nephrotoxicity (odds ratio, 13.4; 95% confidence interval, 1.2 to 148; P = 0.034). A dominant role of the donor's ABCB1 genotype was identified for development of CsA nephrotoxicity. This suggests that P-glycoprotein is an important factor in CsA nephrotoxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Accuracy of biopsy needle navigation using the Medarpa system--computed tomography reality superimposed on the site of intervention.

The aim of this work was to determine the accuracy of a new navigational system, Medarpa, with a transparent display superimposing computed tomography (CT) reality on the site of intervention. Medarpa uses an optical and an electromagnetic tracking system which allows tracking of instruments, the radiologist and the transparent display. The display superimposes a CT view of a phantom chest on a phantom chest model, in real time. In group A, needle positioning was performed using the Medarpa system. Three targets (diameter 1.5 mm) located inside the phantom were punctured. In group B, the same targets were used to perform standard CT-guided puncturing using the single-slice technique. The same needles were used in both groups (15 G, 15 cm). A total of 42 punctures were performed in each group. Post puncture, CT scans were made to verify needle tip positions. The mean deviation from the needle tip to the targets was 6.65+/-1.61 mm for group A (range 3.54-9.51 mm) and 7.05+/-1.33 mm for group B (range 4.10-9.45 mm). No significant difference was found between group A and group B for any target (p>0.05). No significant difference was found between the targets of the same group (p>0.05). The accuracy in needle puncturing using the augmented reality system, Medarpa, matches the accuracy achieved by CT-guided puncturing technique.

Biopsy, Needle↗

PubMed2004

MDCT of the proximal anastomoses created by nitinol implants in coronary artery bypass grafting: a retrospective two-observer evaluation.

The purpose of this study was to investigate the proximal anastomosis of CABG grafts created by a nitinol aortic connector. After receiving CABG, 33 patients underwent CT examination of the heart. On the same patients, CT was performed on postoperative day 5 (4-row CT, group A) and again 1 year thereafter (16-row CT, group B). Twenty-three ACVB to RCX and 27 ACVB to RCA grafts were included. Every anastomosis was reviewed under different reformations (MIP, MPR and VRT). Interobserver correlation was determined. Five days postoperatively, 48/50 anastomoses were classified as patent. One year postoperatively, 42/50 anastomoses were classified as patent. In both groups, the aortic connector could be visualized with good quality: 1.82+/-1.10 (group A) and 1.93+/-1.22 (group B) for ACVB to RCA, similar results for ACVB to RCX grafts (MPR). Image quality at the aortic connector site did not display a significant difference for any reformation between groups (P>0.05). Within groups, MPR displayed better visualization than MIP and VRT (P<0.05). In the presence of metal implants, CT provides reliable data in evaluation of the proximal anastomosis. Sixteen-row CT does not bring a significant benefit to image quality. MPR displayed the best visualization within both groups.

Aged↗

PubMed2004

Visualisation of non-invasive coronary bypass imaging: 4-row vs. 16-row multidetector computed tomography.

UNLABELLED: The purpose of this study was to investigate the image quality of coronary artery bypass graft visualization in 4- and 16-row multidetector CT using multiple imaging reformations. MATERIAL AND METHODS: One hundred sixteen patients underwent CT examination of the heart after receiving CABG. Group A (n=58) received 4-row MDCT; group B (n=58) received 16-row MDCT. Various bypass types such as LITA to LAD and venous grafts to the RCA and RCX were included in the study. A five-point Likert scale was used to grade image quality. Each bypass was reviewed under different imaging reformations: thin slap maximum intensity projection (MIP thin), multiplanar reformation (MPR) and volume rendering technique (VRT). Special attention was paid to the delineation of the distal anastomosis. Interobserver correlation was determined. RESULTS: From 289 bypass grafts examined, 279 (96.54%) were classified as patent and 10 (3.46%) as not patent. Except for the distal anastomosis, 16-row MDCT showed significantly better results for all segments of bypasses. Comparison of reformations within group A and B showed that MIP thin (P<0.05) and VRT (P<0.05) displayed better visualization as compared to MPR. CONCLUSION: Significantly better imaging of all bypass types is possible using 16-row MDCT as compared to 4-row MDCT. Assessment of the distal anastomosis yields no difference between 4- and 16-row technology.

Adult↗

PubMed2004

Virtual endoscopy of the tracheo-bronchial system: sub-millimeter collimation with the 16-row multidetector scanner.

The purpose of this study was to evaluate the scope of sub-millimeter collimation reconstruction parameters using 16-row computer tomography and ECG triggering on image quality in virtual bronchoscopy. Thirty-two patients (5 women, 27 men, mean age 66.6+/-1.4) who had been admitted for coronary artery bypass graft surgery underwent CT examination of the thorax (Sensation 16, Siemens, Inc., Forchheim, Germany). All patients were examined with 16x0.75-mm collimation. Image reconstruction was performed for two groups. In group A ( n=32), slice thickness of 1.5 mm and an overlap of 0.75 mm were used. In group B ( n=32), slice thickness of 0.75 mm and an overlap of 0.4 mm were applied. Retrospective ECG triggering was performed in all patients. The maximum order of recognizable bronchi was determined in each data set. In addition to assessing the maximum order of bronchial bifurcation, bronchial diameter was determined in truly perpendicular sections in each patient. For every segment proximal to a bifurcation, image quality was subjectively graded as poor (grade 1), moderate (grade 2) or good (grade 3). The observers were asked to identify the minimum cardiac movement ECG-triggered image sets assuming that they would be of better quality than the maximum cardiac movement ECG-triggered image sets. The Mann-Whitney U-test and the Fisher's Exact Test were used for statistical evaluation. In group A, a mean of 4.8+/-0.2 bifurcations was ascertained vs. 6.5+/-0.3 bifurcations in group B [ P<0.0003]. For bronchial diameters in group A, a mean of 7.5+/-0.4 mm was determined vs. 4.6+/-0.4 mm in group B [ P<0.0001]. In group B, two independent radiologists observed a significant shift to better image quality in all segments evaluated [ P<0.006 to P<0.000001]. Motion artifacts were judged as being significantly reduced by minimum cardiac movement ECG-triggering in group B [observer 1: P=0.0007 (20/32); observer 2: P=0.008 (18/32)], but not in group A [observer 1: P=0.286 (13/32); observer 2: P=0.123 (16/32)]. Sub-millimeter collimation and minimum cardiac movement ECG-triggered data acquisition allow deeper penetration into the tracheo-bronchial system allowing visualization of the bronchial surface down to diameters below 5 mm in certain cases up to the eighth bifurcation. Along with an enhanced visualization as such, better image quality is acquired in all segments evaluated. Trade off between better image quality, of doubtful diagnostic consequence, and much higher irradiation dose must be made.

Aged↗

PubMed2003

Multidetector-row cardiac CT: diagnostic value of calcium scoring and CT coronary angiography in patients with symptomatic, but atypical, chest pain.

The aim of this study was to investigate the accuracy of multidetector-row cardiac CT (MDCT), calcium scoring (Ca-Sc), and MDCT coronary angiography (MD CTA) in the assessment of coronary atherosclerosis. Thirty-eight patients underwent invasive coronary angiography (CA) and MDCT (collimation 4x1 mm, pitch 1.5 mm, TI 500 ms, 120 kV, 300 mAs, and retrospective ECG-gating). Calcium scoring was calculated for the total coronary artery territory and for RCA, LCA, and LCX separately. The MD CTA served to assess the degree and the localization of stenoses. All findings were compared to invasive coronary angiography. Approximately 68.4% (390 of 570) of all coronary segments could be visualized by MDCT. Correlation coefficient for MD CTA and CA amounted to r=0.58, showing distinct differences for the individual segments. Proximal segments generally showed better correlation (range 0.81-0.77) than medial segments (range 0.91-0.20), distal segments (range 0.55-0.04), or side branches (range 0.76-0.00). Patients with hemodynamically relevant (>75%) stenoses were detected by MD CTA with 72.2% sensitivity (13 of 18) and 100% specificity (20 of 20). For Ca-Sc sensitivity ranged between 94.7% (17 of 18) and 66.7% (12 of 18), specificity between 20% (4 of 20) and 80% (16 of 20) respectively, depending on the prevailing cutoff value. Combination of both methods led to 83.3% sensitivity (15 of 18) and 100% specificity (20 of 20), reaching no level of significance as compared with Ca-Sc (p=0.73) or MD CTA (p=0.23) alone. Calcium scoring as a single method showed highest sensitivity in the detection of coronary atherosclerosis but at the expense of low specificity. In patients with no or moderate calcifications, combination with MD CTA helped to distinctly increase specificity and NPV.

Adult↗

PubMed2003

ADP- and oligomycin-sensitive redox behavior of F0 b thiol in ATPsynthase depends on neighbored primary structure: investigations using 14-C-labeled alpha lipoic acid.

Purified ATPsynthase of bovine heart mitochondria has been analyzed for its mobility and reactivity of oligomycin-sensitive sulfhydryl regions in presence of the substrate ADP and oligomycin. Labeling of thiol groups at the hydrophobic F_0 region of the ATPsynthase was increased in the enzyme initially treated with SDS, N-ethylmaleimide and dithiothreitol (modified enzyme). After dialysis or gel permeation the ATPsynthase was treated with [14C] alpha lipoic acid at a molar ratio of 35-85/1 (lipoic acid/ATPsynthase) corresponding to 4-8.6 nmol/mg protein. Under these conditions, ATPase activity of the native enzyme was significantly decreased. After preincubation with ADP, PAGE of the native, [14C] labeled enzyme revealed an increase of radioactivity at a region of 25 kDa deduced to Cys 197 of subunit b. In the modified enzyme the increase in radioactivity was found at 10 kDa. In this context, the sequence Lys-Cys-Ile around Cys 197 of subunit b suggests excessive reactivity of this thiol, as well as ready reversibility by -SH-S-S- interchange. Therefore, previously observed reaction by thiol reagents and antioxidants from outside the mitochondrion can be interpreted with Cys 197 of F0 b. It accounts for sulfhydryl unmasked by binding of ADP at F1.

Adenosine Diphosphate↗