The ultrastructure of parapapillary chorioretinal atrophy in eyes with secondary angle closure glaucoma

Background: The present study was performed to investigate the ultrastructure of deep retinal layers and choroid corresponding to the parapapillary chorioretinal atrophy in eyes with secondary angle-closure glaucoma. Methods: The glaucomatous eyes included two eyes enucleated due to iris ring melanoma with high intraocular pressure and one eye with neovascular glaucoma enucleated due to ocular pain. The control eyes included one eye enucleated due to choroidal malignant melanoma with normal intraocular pressure and one eye enucleated during surgery for supramandibular carcinoma. These eyes were studied with light and electron microscopy. Results: In the region of parapapillary chorioretinal atrophy of glaucomatous eyes, the retinal pigment epithelial cells showed degenerative changes, such as loss of basal in foldings and microvilli, degenerated mitochondria, vacuolar degeneration and irregular distribution of melanin granules. The photoreceptors were decreased in number in this area of glaucomatous eyes. The lumen of the choriocapillary vessels adjacent to the optic nerve was collapsed. Conclusion: These results elucidate the fine structures of deep retina and choroid in the region of parapapillary chorioretinal atrophy of glaucomatous eyes, and suggest that the reduced choroidal perfusion might be the pathogenetic mechanism of glaucomatous parapapillary chorioretinal atrophy.     

Sauerstoffverbrauch und Alterung in Langzeitkulturen von Linsenepithel

Zusammenfassung Mit Hilfe der beschriebenen Technik gelang es, Linsenepithelien über 40 Passagen zu züchten; zugleich fanden morphologische Alterungsveränderungen und Sauerstoffverbrauch der Zellen im Warburg-Apparat Beachtung. Vergleichbare Untersuchungen sind derzeit nicht bekannt. Morphologisch überwogen Alterationen wie Vergrößerung des Zelleibes neben bekannten Degenerationszeichen. Der Sauerstoffverbrauch von 2 l pro Stunde pro 10⁵ Zellen zeigte sich in konstanter Höhe bis zur 39. Passage und sank dann abrupt auf etwa ein Viertel. Nachdem die Zellen ohne ersichtlichen Grund danach plötzlich starben, liegt die Folgerung nahe, daß der aerobe Stoffwechsel der Linsenepithelien unabhängig von ihrem Alter und ohne sich signifikant abzeichnenden Tagesrhythmus mit ihrem Überleben verbunden erscheint.

---

Oxygen consumption and aging in longterm cultures of lens epithelia

By means of the described technique lens epithelia were cultured in 40 subcultures; at the same time, both the morphological aging processes and oxygen consumption of the cells, were observed using the Warburg respirometer. To date comparable studies are not available. Morphologically, cell enlargement took place in conjunction with signs of degeneration. Oxygen consumption of 2 l per hour per 10⁵ cells ±0.8 remained at a constant level without any significant diurnal rhythm up to subculture 39 and then suddenly fell to about one-fourth of the initial value. As the cells died of an unknown cause, it was concluded that the aerobic metabolism of lens epithelia seemed to be linked to survival without being age related.

---

---

Herrn Prof. Dr. E. Schreck, dem damaligen Direktor der Klinik, in Dankbarkeit zum 70. Geburtstag     

Circulating growth factor levels are associated with tumorigenesis in neurofibromatosis type 1.

PURPOSE: Neurofibromatosis type 1 (NF1) is characterized by systemic development of neurofibromas. Early clinical diagnosis can be ambiguous, and genetic diagnosis can be prohibitively difficult. Dysregulation of a number of growth factors has been suggested to be a mechanism of pathogenesis. This study was performed to assess the contribution of circulating growth factors for diffuse tumorigenesis and the diagnostic value of circulating growth factor identification in serum. EXPERIMENTAL DESIGN: The growth stimulation of neurofibroma-derived cells by serum from NF1 patients was tested, and serum growth factor levels in a cohort of NF1 patients (n = 39) between the ages of 7 and 70 years were analyzed. RESULTS: Concentrations of midkine (MK) and stem cell factor, but not epidermal growth factor, were substantially increased in serum of NF1 patients when compared with healthy controls. Within the NF1 group, MK levels increased dramatically at puberty from an average of 0.79 ng/mL in patients <18 years to 1.18 ng/mL in patients >18 years old. Stem cell factor and MK concentrations above a defined threshold in serum of NF1 patients are of diagnostic benefit for 96% of patients in the cohort tested. Furthermore, serum from NF1 patients enhanced proliferation of human neurofibroma-derived primary Schwann cells and endothelial cells substantially better than normal serum. CONCLUSIONS: Enhanced circulating growth factor levels contribute to diffuse tumorigenesis in NF1 and may provide the basis for molecular diagnosis.     

Analysis of concerted expression of angiogenic growth factors in acute myeloid leukemia: expression of angiopoietin-2 represents an independent prognostic factor for overall survival.

PURPOSE: Bone marrow neoangiogenesis plays an important pathogenetic and possible prognostic role in acute myeloid leukemia (AML). Members of the vascular endothelial growth factor (VEGF) and angiopoietin family represent the most specific inducers of angiogenesis secreted by AML blasts. We therefore correlated expression of angiogenic factors with clinical variables. PATIENTS AND METHODS: We investigated the expression of VEGF-A, VEGF-C, angiopoietin-1 (Ang1), angiopoietin-2 (Ang2), and the receptor Tie2 by quantitative polymerase chain reaction in a cohort of 90 patients younger than 61 years with de novo AML entered into the German AML Süddeutsche H?moblastose Gruppe Hannover 95 trial. Uni- and multivariate analyses were performed using clinical and gene expression variables. RESULTS: Univariate analysis of overall survival indicated the following variables as prognostic factors: good response on a day-15 bone marrow examination after initiation of induction chemotherapy, karyotype, and high Ang2 expression. In multivariate analysis, only bad response and log Ang2 expression remained of statistical significance, with a hazard ratio of 3.51 (95% CI, 1.91 to 6.47) and 0.75 (95% CI, 0.61 to 0.91), respectively. Subgroup analysis suggested that the prognostic impact of Ang2 expression was especially evident in cohorts with low VEGF-C and Ang1 mRNA levels. CONCLUSION: These results show that expression of Ang2 represents an independent prognostic factor in AML. Additional research into interactions of angiogenic cytokines in the pathogenesis of bone marrow angiogenesis in AML is warranted.     

Effectiveness of averaging strategies to reduce variance in retinal nerve fibre layer thickness measurements using spectral-domain optical coherence tomography

Background

Automated detection of subtle changes in peripapillary retinal nerve fibre layer thickness (RNFLT) over time using optical coherence tomography (OCT) is limited by inherent image quality before layer segmentation, stabilization of the scan on the peripapillary retina and its precise placement on repeated scans. The present study evaluates image quality and reproducibility of spectral domain (SD)-OCT comparing different rates of automatic real-time tracking (ART).

Methods

Peripapillary RNFLT was measured in 40 healthy eyes on six different days using SD-OCT with an eye-tracking system. Image brightness of OCT with unaveraged single frame B-scans was compared to images using ART of 16 B-scans and 100 averaged frames. Short-term and day-to-day reproducibility was evaluated by calculation of intraindividual coefficients of variation (CV) and intraclass correlation coefficients (ICC) for single measurements as well as for seven repeated measurements per study day.

Results

Image brightness, short-term reproducibility, and day-to-day reproducibility were significantly improved using ART of 100 frames compared to one and 16 frames. Short-term CV was reduced from 0.94?±?0.31 % and 0.91?±?0.54 % in scans of one and 16 frames to 0.56?±?0.42 % in scans of 100 averaged frames (P?≤?0.003 each). Day-to-day CV was reduced from 0.98?±?0.86 % and 0.78?±?0.56 % to 0.53?±?0.43 % (P?≤?0.022 each). The range of ICC was 0.94 to 0.99. Sample size calculations for detecting changes of RNFLT over time in the range of 2 to 5 μm were performed based on intraindividual variability.

Conclusion

Image quality and reproducibility of mean peripapillary RNFLT measurements using SD-OCT is improved by averaging OCT images with eye-tracking compared to unaveraged single frame images. Further improvement is achieved by increasing the amount of frames per measurement, and by averaging values of repeated measurements per session. These strategies may allow a more accurate evaluation of RNFLT reduction in clinical trials observing optic nerve degeneration.     

The role of choroidal hypoperfusion associated with photodynamic therapy in neovascular age-related macular degeneration and the consequences for combination strategies

The clinical benefits of verteporfin therapy have been documented in a wide variety of patients with choroidal neovascularization (CNV) due to age-related macular degeneration (AMD), and there is encouraging evidence of improved outcomes when this angioocclusive modality is combined with antiangiogenic agents. Although the clinical benefits of verteporfin mono- and combination therapy are well established, there has been concern that treatment with verteporfin results in hypoperfusion in the treated area and that concomitant use of antiangiogenic agents could prolong this effect. However, despite well-documented occurrences of hypoperfusion on fluorescein and indocyanine green angiography, there is little evidence of associations with functional impairment or other adverse effects. It has also been suggested that hypoperfusion might actually help to reduce recanalization of CNV and permit neuronal recovery by decreasing exposure to oxygen and oxidative radicals. The reduced need for frequent retreatments clearly has a major appeal due to the lower costs associated with fewer interventions and reduced burden of clinical monitoring and diagnostic reevaluations. Ongoing evaluation in randomized clinical trials will provide further clarification on the effect of verteporfin plus ranibizumab compared with ranibizumab monotherapy in terms of visual acuity, anatomical outcomes, treatment frequency, and health economics. The results of these large-scale clinical trials will provide a strong basis for determining the benefits and risks of combination therapy.