[Measurement of the central corneal thickness using optical reflectometry and ultrasound]. / Messung der zentralen Hornhautdicke mittels optischer Reflektometrie im Vergleich zur Ultraschall-Pachymetrie.

AIM: The aim of this study was to evaluate measurements of the central corneal thickness using OLCR and ultrasound pachymetry (IOPac). MATERIALS AND METHODS: In a retrospective observational study, fifty patients were assessed. Central corneal thickness was measured using OLCR and ultrasound. RESULTS: The IOPac system shows results for the central corneal thickness between 419 µm and 613 µm. The OLCR values ranged between 421 and 598 µm. The coefficient of variation was 1.12 % in the case of the IOPac and 0.97 % in the case of the OLCR. The paired Student's t-test showed no significant differences between the two methods. The agreement between the two methods was high with r = 0.929. CONCLUSIONS: The agreement between the results for the central corneal thickness using OLCR and ultrasound is high. The OLCR is a non-touch technology that does not require local anaesthesia, thus further reducing the risk of infection or mechanical trauma. Especially in surgical applications or glaucoma assessments, movement artefacts need to be ruled out, which potentially could cause wrong values and thus lead to wrong decisions.

[Potential endogenous immunological self-protection of uveal melanoma by indoleamine 2,3-dioxygenase]. / Potenzieller endogener, immunologischer Schutzmechanismus uvealer Melanome durch Indoleamine 2,3-Dioxygenase.

BACKGROUND: Uveal melanomas are the most common intraocular tumours in the adult. Although they represent less than 1% of all tumour cases, uveal melanomas are considerd to be rather aggressive due to early hepatic metastases. Indoleamine 2,3-dioxygenase (IDO) is the principle enzyme in the degradation of the essential amino acid L-tryptophan to L-kynurenine. MATERIALS AND METHODS: In this study, the L-kynurenine production of six uveal melanoma cell lines was examined and immunohistochemistry performed for detection of IDO expression within uveal melanomas. RESULTS: In all the examined cell lines, a basal degradation of tryptophan to L-kynurenine was detectable. Supplementation with interferon-gamma could up-regulate this basal L-kynurenine production. The expression of IDO using immunohistochemistry was demonstrated within all examined tumours. CONCLUSIONS: The expression of IDO within the tumours may shed light on an important adaptive mechanism which allows the melanoma cells to escape T-cell-dependent immunosurveillance as soon as these cells metastise and enter non-immunologically privileged tissue. As competitive inhibition of IDO by 1-methyl-tryptophan is possible, a new therapeutic pathway might be available.

[Reduction of lipid peroxidation and apoptosis in corneal endothelial cells by vitamin A]. / Verminderung der Lipidperoxidation und der Apoptoserate in kornealen Endothelzellen durch Vitamin A.

PURPOSE: The goal of this study was to determine the effects of lipid peroxidation-mediated toxicity of iron ions on corneal endothelial cells leading to apoptosis. METHODS: Murine corneal endothelial cells were maintained in tissue culture medium supplemented with free iron ions, known to lead to increased lipid peroxidation. Retinoic acid in the cell supernatant and cytoplasm of these cells was determined using HPLC. The rate of apoptosis was assessed by quantification of caspase-3-like activity. The lipid peroxidation was measured using the malondialdehyde method. Supplementation of retinoic acid was tested in the setting of apoptosis. RESULTS: Free iron ions led to a rapid loss of retinoic acid in the supernatant and the corneal endothelial cells. This was correlated with rising levels of malondialdehyde following oxidative stress and increased apoptosis. Supplementation of retinoic acid alone significantly reduced oxidative stress and apoptosis in the respective cells. CONCLUSION: In this study the authors present a novel in vitro model to test the direct influence of pro-oxidative species on corneal endothelial cells. The authors also prove that supplementing corneal endothelial cells with retinoic acid sufficiently prevents free radical injury and apoptosis.

[Comparison of several viral vectors for gene therapy of corneal endothelial cells]. / Vergleich verschiedener viraler Vektoren zur Gentherapie von Hornhautendothelzellen.

AIM: In this paper we compare the transduction efficiency, toxicity, and safety of retroviral vectors [equine infectious anemia virus (EIAV), human immunodeficiency virus-1 (HIV-1), human foamy virus (PFV] and adenovirus (Ad) for potential use in gene therapy of corneal endothelial cells. METHOD: Murine corneal endothelial cells were transduced with EIAV, HIV-1, PFV, and Ad, resulting in the overexpression of a green fluorescent protein (eGFP) transgene marker. The transduction efficiency was assessed by flow cytometry, while cytotoxicity and apoptosis rate were detected by annexin V/propidium iodide (PI) stain. RESULTS: Ad had the highest transduction efficiency with 99% of the cells expressing the transgene, followed by EIAV (95%), HIV-1 (75%), and PFV (43%). However, the high transduction efficiency of Ad also resulted in the highest apoptosis rate (25%) in the corneal endothelial cells. There was no detectable difference in the toxicity between PFV and HIV-1 (10%). EIAV transduction had the lowest cytotoxicity, with only 3% of the cells being annexin V/PI positive. CONCLUSION: Compared to other vectors EIAV exhibited high transduction efficiency combined with low toxicity to corneal endothelial cells. Therefore, it is a powerful tool for gene therapy applications in selected corneal endothelial diseases.

Enhanced accumulation of the isoprostane, 8-epi-PGF2 alpha, in human aortic and pulmonary valves of patients with coronary heart disease.

The aim of the present study was to investigate whether the isoprostane 8-epi-PGF2 alpha differently accumulates in semilunar valves of patients suffering from coronary heart disease (CHD, n = 19) as compared to valves from healthy heart donors (controls, n = 6). Sections from isolated aortic and pulmonary valves were analyzed by semiquantitative immunohistochemistry. The 8-epi-PGF2 alpha-content was determined by using a specific radioimmunoassay. The accumulation of 8-epi-PGF2 alpha in both valves was higher in CHD-patients in comparison to controls (Aortic valves: 36.49 +/- 11.26% vs. 15.78 +/- 3.04%; pulmonary valves: 46.79 +/- 9.80% vs. 14.99 +/- 3.57%). The results from the radioimmunoassay revealed comparable findings in both groups (CHD vs. controls: 395.95 +/- 86.09 vs. 139.50 +/- 47.46 pg/mg protein in the aortic valves and 430.47 +/- 76.30 vs. 147.33 +/- 53.84 pg/mg protein in pulmonary valves). Pulmonary valves seem to be more susceptible to oxidative stress than aortic valves as evidenced by a higher accumulation of 8-epi-PGF2 alpha in CHD patients. Considering the data presented in this study, we suggest that 8-epi-PGF2 alpha is a valuable indicator of oxidative injury in human semilunar valves.

The isoprostane 8-epi-PGF(2alpha) is a valuable indicator of oxidative injury in human heart valves.

To date, little information is available concerning oxidative injury in human cardiac valves. Therefore, we sought to investigate whether the isoprostane, 8-epi-PGF(2alpha), a novel oxidative stress marker, is localized in aortic and pulmonary valves derived from explanted hearts of patients suffering from idiopathic dilative cardiomyopathy (IDC). By using semiquantitative immunohistochemistry, we demonstrated that 8-epi-PGF(2alpha) is localized in both valves with pulmonary valves accumulating more of this isoprostane compared to aortic valves (36.69+/-12.04% vs. 31.54+/-11.49%, P<.05). These results were confirmed by a radioimmunoassay (RIA) analysis showing a similar, but not significant, difference between the two valves (288.50+/-72.18 pg/mg protein in the pulmonary valves and 267.30+/-58.77 pg/mg protein in aortic valves, P=.09). Considering the data presented in this study, we suggest that 8-epi-PGF(2alpha) is a valuable indicator of oxidative injury in human semilunar valves.

Significance of right bundle branch block in the diagnosis of myocardial ischemia in patients undergoing coronary artery bypass grafting.

BACKGROUND: Perioperative diagnosis of myocardial ischemia following cardiac surgical procedures remains a challenging problem. Particularly, the role of new conduction disturbances as markers of postoperative ischemia is still questionable. The goal of this study was to elucidate the diagnostic significance of new postoperative right bundle branch block (RBBB) for the detection of perioperative myocardial ischemia in patients undergoing elective coronary artery bypass grafting (CABG). METHODS: In 169 consecutive patients, three-channel Holter monitoring and serial assessment of serum enzymes were performed for 48 h, and 12-lead ECG repeated for up to 5 days postoperatively. Postoperative events were classified as either myocardial infarction (MI), transient ischemic events (TIE) or various conduction disturbances. RESULTS: Transient (n=9) or permanent (n=4) RBBB occurred in 13 patients (8%); 14 patients (8%) showed signs of perioperative MI and 18 patients (11%) evidence of TIE. Peak activity of creatine-kinase (CK, 561+/-135 vs. 316+/-19, P<0.05) and CK-MB (22.7+/-3.2 vs. 13.4+/-0.8, P<0.01) were higher in patients with RBBB than in patients without perioperative ischemic events. Peak CK-MB levels were significantly higher in patients with MI as compared to those with RBBB (33.4+/-7.6 vs. 22.7+/-3.2, P<0. 05). Patients with TIE had similar perioperative enzyme levels as patients with no events. CONCLUSION: It is concluded that the combined assessment of repeated 12-lead ECG, continuous Holter monitoring and enzyme analysis allows a reliable diagnosis of perioperative myocardial ischemia and conduction disturbances. The occurrence of new RBBB following elective CABG is indicative of perioperative myocardial necrosis and thus serves as a valuable tool for the diagnosis of new, perioperative ischemic events.

[Immunohistochemical detection of enhanced deposition of isoprostane 8-epi-PGF2alpha in vascular lesions of temporal arteritis]. / Immunhistochemischer Nachweis einer verstärkten Anreicherung von Isoprostan 8-epi-PGF2alpha in den Gefässläsionen bei Arteriitis temporalis.

BACKGROUND AND PURPOSE: Oxidative injury caused by lipid oxidation is considered a major factor in the development of several ocular disorders including temporal arteritis. This study investigates the role of 8-epi-PGF2alpha as a marker of oxidative stress in vivo. PATIENTS AND METHODS: Sections from isolated human temporal arteries, obtained from patients suspected of having giant cell arteritis ( n=22), were analyzed by semiquantitative immunohistochemistry and planimetry. RESULTS: Immunoreactivity for 8-epi-PGF2alpha was significantly higher in patients with temporal arteritis (AT) compared to healthy temporal arteries (Co). The percentage of the areas stained positive in immunohistochemistry was higher in the AT group compared to the control group (Co). The enrichment values in the intimal layer containing the endothelium of the same temporal arteries were also significantly higher ( p<0.01) in temporal arteries of the AT group. CONCLUSIONS: Our findings of an enhanced accumulation of 8-epi-PGF2alpha in areas of the arterial wall subjected to extensive vascular tissue destruction suggest that lipid peroxidation products may also play a role in the pathogenesis of this disease.

[Immunohistochemical detection of altered low density lipoprotein (ox-LDL) in the vessel walls of patients with giant cell arteritis]. / Immunhistochemischer Nachweis veränderter Low-density-Lipoproteine (ox-LDL) in der Gefässwand bei Patienten mit Arteriitis temporalis.

BACKGROUND AND PURPOSE: Recent data indicate that lipid peroxidation is implicated in the pathogenesis of giant cell arteritis with a close anatomic relationship between reactive oxygen species and oxidatively injured vascular tissue. PATIENTS AND METHODS: Immunohistochemistry utilizing anti-ox-LDL was performed on paraffin sections of isolated temporal arteries obtained from patients (n=23) suspected of having temporal arteritis. Enrichment as well as staining intensity of ox-LDL in vascular tissue was analysed by digital image planimetry. RESULTS: Temporal arteries with biopsy proven temporal arteritis (n=11) presented with significantly higher enrichment of ox-LDL in the intima (16.9+/-4.2% vs. 11.25+/-2.3%; p<0.01) and mean (9.6+/-2.4% vs. 6.75+/-1.8%; p<0.01) as compared to healthy controls. Comparable results for the staining intensity were found in the intimal (2.8+/-0.5 eU vs. 1.7+/-0.4 eU; p<0.01) and medial layer (1.55+/-0.5 eU vs. 1.04+/-0.6 eU; p<0.01) of diseased patients compared to controls. CONCLUSIONS: Accumulation of ox-LDL in the intimal layer, especially at the intima-media-border, was closely related to disruption of the elastica interna and adjacent vascular tissue, presumably contributing to the underlying process of intimal hyperplasia through unimpeded migration of smooth muscle and accumulation inflammatory cells.

Reproducibility of high-resolution optical coherence tomography measurements of the nerve fibre layer with the new Heidelberg Spectralis optical coherence tomography.

AIM: Conventional time-domain OCT technology for detection of retinal nerve fibre layer (RNFL) neurodegeneration suffers from technical inaccuracy owing to a lack of exact scan centring around the optic disc as well as a true follow-up possibility. In this study, the authors evaluated a novel high-resolution spectral-domain OCT device (SD-OCT) with an incorporated eye-tracking feature in its ability to objectively measure the RNFL thickness (RNFLT) by testing intraobserver reproducibility in a series of healthy volunteers. METHODS: Triplicate circumferential RNFL scans of six peripapillary sectors were obtained from both eyes of all 31 participants. The authors compared the measurements of RNFLT during three separate examination days under miotic (Mi) and mydriatic (My) pupil conditions using a high-speed (HS) and high-resolution (HR) scan-acquisition mode. To examine the intersession reproducibility of the SD-OCT measurements, the mean, SD and coefficient of variation (COV) were calculated. RESULTS: No significant differences were found in all groups, independent of the mode of image acquisition and examination day (p always >0,05). Under all conditions, low COVs between 0.545% and 3.97% (intrasession COV on baseline) were found. The intersession COV with activated follow-up mode ranged between 0.29% and 1.07%. In both settings, the temporal sector showed the highest COV values. CONCLUSIONS: True follow-up measurement of identical peripapillary regions may enable clinicians to detect discrete levels of retinal thickness change over time. This constitutes a crucial prerequisite for a reliable monitoring of subtle RNFL changes in neurodegenerative disorders.