Biomedical subjects

Alexander Claus Langheinrich

Publications and source records attributed to Alexander Claus Langheinrich.

4 recordsLinked to original sources

PubMed2004

Acute rat lung injury: feasibility of assessment with micro-CT.

PURPOSE: To evaluate the feasibility of micro-computed tomography (CT) for analysis of the lung fine structure and its alterations during endotoxin-induced lung injury. MATERIALS AND METHODS: Intravital perfusion-fixed rat lungs with (n = 5) and without (n = 5) endotoxin perfusion were scanned with micro-CT. Three imaging modalities (conventional histology, intravital microscopy, and electron microscopy) were used to document the effect of endotoxin and the in vivo application of contrast agent (a mixture of barium sulfate, gelatin, and thymol). The effect of endotoxin on structural changes of the lung was evaluated with analysis of variance. RESULTS: Intravital microscopy, conventional histology, and electron microscopy demonstrated capillary perfusion of contrast agent, inflated alveoli, and no extravasation of barium sulfate in the extravascular space. Systemic application of endotoxin led to a significant increase in the soft-tissue volume of the lungs (ie, tissue edema) (58.09 microm(3)+/- 4.6 [standard error of the mean] vs 8.31 microm(3)+/- 1.63, P <.001) and significant thickening of the alveolar walls (34.01 microm +/- 4.5 vs 14.83 microm +/- 2.5, P <.001) at micro-CT. Simultaneously, endotoxin-treated rat lungs showed a significant reduction in total air space (49.74 microm(3)+/- 1.72 vs 100.99 microm(3)+/- 1.16, P <.001). CONCLUSION: These findings indicate that micro-CT is feasible for structural evaluation of the lung fine structure and its alterations during endotoxin-induced lung injury.

Animals↗

PubMed2004

Atherosclerotic lesions at micro CT: feasibility for analysis of coronary artery wall in autopsy specimens.

PURPOSE: To evaluate the feasibility of micro computed tomography (CT) for analysis of the coronary artery wall. MATERIALS AND METHODS: With micro CT, two-dimensional transverse images were generated from 10 human autopsy specimens of coronary arteries (2.5-3.5 cm long), with section thickness of 6 microm. Vessel wall perimeter, plaque area, calcified lesion area, media area, and lumen area were determined by three experienced radiologists. Results were compared with those obtained from a detailed conventional histomorphometric analysis of corresponding cross sections. Hotelling T(2) test (a multivariate generalization of the univariate Student t test) and Pearson correlation coefficient were used to assess the correlation between micro CT findings and conventional histologic measurements. The significance of differences in gray-scale measurements was tested with analysis of variance. RESULTS: Micro CT provided quantitative information about plaque morphology equivalent to that provided with histomorphometric analysis. Hotelling T(2) test revealed significantly smaller values for vessel wall perimeter and lumen area with histologic sections (P <.001). Gray-scale measurements were established with which lesions could be categorized after histologic classification. CONCLUSION: Micro CT is feasible for analysis of the coronary artery wall.

Aged↗

PubMed2003

Glomerular filtration rate measured by using triphasic helical CT with a two-point Patlak plot technique.

PURPOSE: To determine the accuracy of the two-point Patlak plot in the calculation of glomerular filtration rate (GFR). MATERIALS AND METHODS: Fifty patients without acute renal disorder were included. GFR was calculated by using a two-point Patlak plot technique. The computed tomography (CT) protocol consisted of a plain examination followed by two contrast material-enhanced examinations in the arterial and portovenous phase. Each examination included the entire kidneys and was performed after injection of 120 mL iopromide and 300 mg of iodine per milliliter given per 75 kg of body weight. All examinations were performed with a standard abdominal protocol. Section thickness was 4 x 2.5 mm, and table advance was 12.5 mm. Bolus triggering commenced 10 seconds after the start of contrast medium injection. Twelve dynamic scans were obtained with reduced tube current every 3 seconds to obtain sufficient arterial input function data. Correction for hematocrit level was made by using the unenhanced attenuation of the aorta. As a reference method, plasma clearance of the contrast medium injected for CT was calculated from three iodine plasma concentration measurements obtained 3, 4, and 5 hours after injection. Linear correlation was performed. RESULTS: GFR was calculated from CT data in 48 patients. Two patients were excluded because of breathing errors. Mean GFR was 80 mL/min (range, 17-153 mL/min) as measured with iopromide plasma clearance and 82 mL/min (range, 28-148 mL/min) as measured with CT. Linear correlation between the two methods was r = 0.889; GFR calculated with the two-point Patlak plot was equal to 15 plus 0.83 times GFR (plasma clearance). The mean difference between GFRs as determined with the two methods was -1.2 mL/min (95% CI: -27.1, 24.6). CONCLUSION: Total GFR can be measured accurately with minimally extended triphasic CT in patients without acute renal disorder by using a two-point Patlak plot technique.

Adult↗

PubMed2003

Effects of 3-deazaadenosine on homocysteine and atherosclerosis in apolipoprotein E-deficient mice.

OBJECTIVE: In the past decade, elevated homocysteine concentration has achieved widespread recognition as an independent risk factor in the development of atherosclerosis. 3-Deazaadenosine (c3Ado) is a potent inhibitor and substrate for S-adenosylhomocysteine hydrolase and therefore may reduce homocysteine concentrations. The current study investigated the effect of c3Ado on serum homocysteine, atherosclerotic lesions, and the expression of adhesion molecules in apoE-knockout mice. METHODS AND RESULTS: Animals were placed on an atherogenic diet with or without c3Ado for 12 and 24 weeks. Frozen cross-sections of the aortic sinus and the proximal aorta were analyzed by computer-aided planimetry for fatty plaque formation. Macrophages, VCAM-1 and ICAM-1 were quantified by immunhistochemistry and oligo-cell reverse transcription polymerase chain reaction after laser microdissection. Application of c3Ado resulted in significant reduction of homocysteine levels by 35.9 and 45.3% after 12 and 24 weeks, respectively (P < 0.001). Neointimal area and atherosclerotic plaque formation were significantly reduced in animals treated with c3Ado (P < 0.01). Moreover, monocyte adhesion and concomitant ICAM-1 and VCAM-1 antigen and RNA expression on the endothelial layer were significantly reduced (P < 0.001, P < 0.01). CONCLUSION: Our results demonstrate that c3Ado induces a marked reduction of homocysteine concentrations which might explain in part the anti-atherogenic effect of the drug.

Analysis of Variance↗