[Spontaneous closure of traumatic macular holes. Two cases]

The optimal treatment approach for traumatic macular holes (TMH) is still controversial. We report two cases of spontaneous closure of TMH. In the first patient, closure resulted in an increase in visual acuity from 0.2 to 0.8. In the second case, no increase in visual acuity was detectable despite spontaneous closure of the TMH within a few days after the trauma. This may be explained by an irreversible damage of the photoreceptors and retinal pigment epithelium. In patients with TMH, a waiting approach should be considered because of the possibility of spontaneous closure of TMHs.

15-Deoxy-delta 12-14-prostaglandin-J2 induces hypertrophy and loss of contractility in human testicular peritubular cells: implications for human male fertility

The wall of the seminiferous tubules contains contractile smooth-muscle-like peritubular cells, thought to be important for sperm transport. Impaired spermatogenesis in men typically involves remodeling of this wall, and we now found that smooth muscle cell (SMC) markers, namely myosin heavy chain (MYH11) and smooth muscle actin (SMA) are often lost or diminished in peritubular cells of testes of men with impaired spermatogenesis. This suggests reduced contractility of the peritubular wall, which may contribute to sub- or infertility. In these cases, testicular expression of cyclooxygenase-2 (COX-2) implies formation of prostaglandins (PGs). When screening different PGs for their ability to target human testicular peritubular cells (HTPCs), only a PG metabolite, 15-deoxy-Delta(12-14)-prostaglandin-J2 (15dPGJ2), was effective. In primary cultures of HTPCs, 15dPGJ2 increased cell size in a reversible manner. Importantly, 15dPGJ2 treatment resulted in a loss of typical differentiation markers for SMCs, namely MYH11, calponin, and SMA, whereas fibroblast markers were unchanged. Collagen gel contraction assays revealed that this loss correlates with a reduced ability to contract. Experiments with an antagonist (bisphenol A diglycidyl ether) and agonist (troglitazone) for a cognate 15dPGJ2 receptor (i.e. peroxisome proliferator-activated receptor-gamma) indicated that peroxisome proliferator-activated receptor-gamma is not directly involved. Rather, the mode of action of 15dPGJ2 involves reactive oxygen species. The antioxidant N-acetylcysteine not only blocked ROS formation but also prevented the increase in cell size and the loss of contractility in HTPCs challenged with 15dPGJ2. We conclude that 15dPGJ2, via reactive oxygen species, influences SMC phenotype and contractility of human peritubular cells and possibly is involved in the development of human male sub-/infertility.

Nuclear EGFR as novel therapeutic target: insights into nuclear translocation and function

Emerging evidence suggests the existence of a new mode of epidermal growth factor receptor (EGFR) signaling in which activated EGFR undergoes nuclear translocation following treatment with ionizing radiation. The authors provide evidence that the nuclear EGFR transport is a stress-specific cellular reaction, which is linked to src-dependent EGFR internalization into caveolae. These flask-shaped pits can fuse with endoplasmic reticulum and the EGFR is sorted into a perinuclear localization. This compartment may serve as a reservoir for nuclear EGFR transport which is regulated by PKCepsilon (protein kinase Cepsilon). Nuclear EGFR is able to induce transcription of genes essential for cell proliferation and cell-cycle regulation. Moreover, nuclear EGFR has physical contact with compounds of the DNA repair machinery and is involved in removal of DNA damage. Anti-EGFR strategies target radiation-associated EGFR nuclear translocation in different manners. EGFR-inhibitory antibodies, i.e., cetuximab (Erbitux((R))), can block nuclear translocation by EGFR immobilization within the cytosol in responder cell lines, whereas tyrosine kinase inhibitors rather target nuclear kinase activity of EGFR linked with cytosolic or nuclear functions. However, both strategies can inhibit DNA repair following irradiation.

[Interstitial nephritis]

Drugs such as antibiotics, non-steroidal anti-inflammatory drugs and proton pump inhibitors, infections and systemic diseases can trigger interstitial nephritis. The clinical outcome varies from asymptomatic progression to acute kidney injury. Interstitial nephritis often leads to characteristic and detectable partial tubular disorders such as tubular proteinuria (alpha(1)-microglobulin), phosphaturia with hypophosphatemia, aminoaciduria, diminished H(+) secretion with metabolic acidosis with inadequate high urinary pH, glucosuria and salt loss. The main principle of treatment is avoidance of the inducing agent. In addition corticosteroids have been proven usable after exclusion of an infection so that a good prognosis can be expected for acute nephritis in the majority of cases. In chronic forms the interstitial nephritis involves the glomeruli as well as potentially resulting in end-stage renal failure in the long run. Supportive therapies are then required in the sense of chronic renal failure in order to prevent further functional loss up to end-stage renal disease.

Radiation-induced lipid peroxidation activates src kinase and triggers nuclear EGFR transport

PURPOSE

Elucidation of the molecular mechanism of radiation-induced activation of src kinase, which initiates EGFR internalization and nuclear transport.

MATERIAL AND METHODS

Radiation-induced src activation was investigated in the bronchial carcinoma cell line A549. Proteins were Western blotted and quantified by the help of specific antibodies. Residual DNA-damage was quantified with gammaH(2)AX-foci analysis. Radiation-induced lipid peroxidation was prevented by acetyl-cysteine.

RESULTS

The radiation-induced src activation and EGFR stabilization could be mimicked by addition of hydroxy-nonenal (HNE), one of the major lipid peroxidation products. Radiation-generated HNE is bound to EGFR and src and correlated with complex formation between both following radiation. Treatment with HNE activated src and stimulated radiation-associated EGFR and caveolin 1 phosphorylations resulting in increased nuclear transport of EGFR. Consequently, radiation-induced phosphorylation and activation of DNA-PK were increased. This phosphorylation was associated with improved removal of residual damage 24h after irradiation. Inhibition of radiation-induced HNE generation by acetyl-cysteine blocked radiation-induced src activation and EGFR phosphorylation.

CONCLUSIONS

HNE generated in response to radiation exposure activates src kinase and is involved in regulation of radiation-stimulated DNA-repair processes.

Placebo-controlled, double-blind, prospective, randomized study of the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors: A report from the PROMID study group

4508

Background: Octreotide is currently used for the control of symptoms in patients with gastroenteropancreatic neuroendocrine tumors (NETs). However, the ability of long-acting somatostatin analogues to control the growth of well-differentiated metastatic NETs is a matter of debate. The analysis of the first randomized, double-blind, placebo-controlled, multicenter, phase IIIb study of octreotide LAR in patients with metastatic NETs of the midgut is presented. Methods: Treatment-naïve patients with histologically confirmed locally inoperable or metastasized well-differentiated NETs and a Karnofsky index >60 were randomized to receive either octreotide LAR 30 mg/month (mo) or placebo for 18 mos, or until tumor progression or death. The primary endpoint was median time to tumor progression. Secondary endpoints included objective tumor response rate (WHO criteria), measured every 3 mos, as well as symptom control and overall survival. This was a planned interim analysis using the Lan-DeMets error spending approach. Results: Eighty-five patients (n=43 octreotide LAR; n=42 placebo) have been enrolled to date and data from 67 patients with tumor progressions and 16 deaths (n=7 octreotide LAR; n=9 placebo) are included here. Median time to tumor progression in the octreotide LAR and placebo groups were 14.3 mos and 6 mos, respectively (HR: 0.34; 95% CI: 0.20–0.59; P=0.000072). After 6 mos of treatment, stable disease was seen in 67% and 37.2% of patients treated with octreotide LAR and placebo, respectively. Due to the low number of observed deaths, median survival time could not be estimated. Conclusions: Octreotide LAR significantly lengthens median time to tumor progression compared with placebo in patients with metastatic NETs of the midgut. Patients treated with octreotide LAR had a 66% risk reduction of tumor progression compared with patients receiving placebo. Octreotide LAR demonstrates substantial tumor control and shows a more favorable antiproliferative response than placebo as two-thirds of patients treated with octreotide LAR achieved stable disease at 6 mos.

[Table: see text]

NuGO contributions to GenePattern

NuGO, the European Nutrigenomics Organization, utilizes 31 powerful computers for, e.g., data storage and analysis. These so-called black boxes (NBXses) are located at the sites of different partners. NuGO decided to use GenePattern as the preferred genomic analysis tool on each NBX. To handle the custom made Affymetrix NuGO arrays, new NuGO modules are added to GenePattern. These NuGO modules execute the latest Bioconductor version ensuring up-to-date annotations and access to the latest scientific developments. The following GenePattern modules are provided by NuGO: NuGOArrayQualityAnalysis for comprehensive quality control, NuGOExpressionFileCreator for import and normalization of data, LimmaAnalysis for identification of differentially expressed genes, TopGoAnalysis for calculation of GO enrichment, and GetResultForGo for retrieval of information on genes associated with specific GO terms. All together, these NuGO modules allow comprehensive, up-to-date, and user friendly analysis of Affymetrix data. A special feature of the NuGO modules is that for analysis they allow the use of either the standard Affymetrix or the MBNI custom CDF-files, which remap probes based on current knowledge. In both cases a .chip-file is created to enable GSEA analysis. The NuGO GenePattern installations are distributed as binary Ubuntu (.deb) packages via the NuGO repository.

Asymmetric caging in soft colloidal mixtures

The long-standing observations that different amorphous materials exhibit a pronounced enhancement of viscosity and eventually vitrify on compression or cooling continue to fascinate and challenge scientists, on the ground of their physical origin and practical implications. Glass formation is a generic phenomenon, observed in physically quite distinct systems that encompass hard and soft particles. It is believed that a common underlying scenario, namely cage formation, drives dynamical arrest, especially at high concentrations. Here, we identify a novel, asymmetric glassy state in soft colloidal mixtures, which is characterized by strongly anisotropically distorted cages, bearing similarities to those of hard-sphere glasses under shear. The anisotropy is induced by the presence of soft additives. This phenomenon seems to be generic to soft colloids and its origins lie in the penetrability of the constituent particles. The resulting phase diagram for mixtures of soft particles is clearly distinct from that of hard-sphere mixtures and brings forward a rich variety of vitrified states that delineate an ergodic lake in the parameter space spanned by the size ratio between the two components and by the concentration of the additives. Thus, a new route opens for the rational design of soft particles with desired tunable rheological properties.

Radiation-induced caveolin-1 associated EGFR internalization is linked with nuclear EGFR transport and activation of DNA-PK

Background

To elucidate the role of src kinase in caveolin-1 driven internalization and nuclear transport of EGFR linked to regulation of DNA-repair in irradiated cells.

Results

Ionizing radiation resulted in src kinase stabilization, activation and subsequent src mediated caveolin-1 Y14- and EGFR Y845-phosphorylations. Both phosphorylations were radiation specific and could not be observed after treatment with EGF. Inhibition of EGFR by the antibody Erbitux resulted in a strong accumulation of caveolin/EGFR complexes within the cytoplasm, which could not be further increased by irradiation. Radiation-induced caveolin-1- and EGFR-phosphorylations were associated with nuclear EGFR transport and activation of DNA-PK, as detected by phosphorylation at T2609. Blockage of src activity by the specific inhibitor PP2, decreased nuclear transport of EGFR and inhibited caveolin-1- and DNA-PK-phosphorylation. Knockdown of src by specific siRNA blocked EGFR phosphorylation at Y845, phosphorylation of caveolin-1 at Y14 and abolished EGFR transport into the nucleus and phosphorylation of DNA-PK. Consequently, both knockdown of src by specific siRNA and also inhibition of src activity by PP2 resulted in an enhanced residual DNA-damage as quantified 24 h after irradiation and increased radiosensitivity.

Conclusion

Src kinase activation following irradiation triggered caveolin-1 dependent EGFR internalization into caveolae. Subsequently EGFR shuttled into the nucleus. As a consequence, inhibition of internalization and nuclear transport of EGFR blocked radiation-induced phosphorylation of DNA-PK and hampered repair of radiation-induced double strand breaks.

Asymmetric dimethylarginine (ADMA) is tightly correlated with growth in juveniles without correlations to obesity related disorders

BACKGROUND

Asymmetrical dimethylarginine (ADMA) was found to be increased in conditions associated with atherosclerosis and metabolic disorders. We investigated ADMA in obese juveniles with pre-atherosclerotic symptoms and in normal weight juveniles.

DESIGN

To elucidate correlations of ADMA in juveniles with obesity related disorders such as insulin resistance, low grade inflammation, hypertension and pre-atherosclerosis, we analysed ADMA by high performance liquid chromatography (HPLC) in 68 obese and 68 healthy, age and gender matched juveniles.

RESULTS

ADMA levels are slightly, but significantly increased (p=0.04) in obese (0.78+/-0.01 micromol/l), compared to normal weight juveniles (0.74+/-0.01 micromol/l). There are no robust correlations of ADMA with obesity related disorders, like dyslipidemia, hypertension, low-grade inflammation and pre-atherosclerosis. Age, body length and alkaline phosphatase, as markers of growth are correlated with ADMA. Multiple testing revealed that, alkaline phosphatase turned out as highly significant positively correlated with ADMA in normal weight (r=0.45/p<0.0001) and obese (r=0.59/p<0.0001) children.

CONCLUSIONS

We show here, that ADMA is slightly increased in obese juveniles without any robust correlations to obesity related disorders. ADMA is tightly correlated with alkaline phosphatase as a marker of growth in obese and normal weight, healthy juveniles.

N-acetylmuramic acid 6-phosphate lyases (MurNAc etherases): role in cell wall metabolism, distribution, structure, and mechanism

MurNAc etherases cleave the unique D-lactyl ether bond of the bacterial cell wall sugar N-acetylmuramic acid (MurNAc). Members of this newly discovered family of enzymes are widely distributed among bacteria and are required to utilize peptidoglycan fragments obtained either from the environment or from the endogenous cell wall (i.e., recycling). MurNAc etherases are strictly dependent on the substrate MurNAc possessing a free reducing end and a phosphoryl group at C6. They carry a single conserved sugar phosphate isomerase/sugar phosphate-binding (SIS) domain to which MurNAc 6-phosphate is bound. Two subunits form an enzymatically active homodimer that structurally resembles the isomerase module of the double-SIS domain protein GlmS, the glucosamine 6-phosphate synthase. Structural comparison provides insights into the two-step lyase-type reaction mechanism of MurNAc etherases: beta-elimination of the D-lactic acid substituent proceeds through a 2,3-unsaturated sugar intermediate to which water is subsequently added.

The radioprotector Bowman-Birk proteinase inhibitor stimulates DNA repair via epidermal growth factor receptor phosphorylation and nuclear transport

BACKGROUND AND PURPOSE

The purpose of the study was to elucidate the underlying molecular mechanism of the radioprotector, Bowman-Birk proteinase inhibitor (BBI), and its interaction with EGFR nuclear transport.

MATERIALS AND METHODS

Molecular effects of BBI at the level of EGFR responses were investigated in vitro with wt. TP53 bronchial carcinoma cell line A549 and the transformed fibroblast cell line HH4dd characterized by a mt. TP53. EGFR and associated protein expression were quantified by Western blotting and confocal microscopy in the cytoplasmic and nuclear cell fraction. Residual DNA double strand breaks were quantified by means of a gammaH(2)AX focus assay.

RESULTS

Both irradiation and BBI-treatment stimulated EGFR internalization into the cytoplasm. This process involved src kinase activation, EGFR phosphorylation at Y845, and caveolin 1 phosphorylation at Y14. EGFR internalization correlated with nuclear EGFR transport and was associated with phosphorylation of EGFR at T654. Nuclear EGFR was linked with DNA-PK complex formation and activation. Furthermore, nuclear EGFR was found in complex with TP53, phosphorylated at S15, and with MDC1, following irradiation and BBI treatment. It is noteworthy that MDC1 was strongly decreased in the nuclear EGFR complex in cells with mt. TP53 and failed to be increased by either BBI treatment or irradiation. Interestingly, in cells with mt. TP53 the BBI mediated stimulation of double strand break repair was hampered significantly.

CONCLUSION

These data indicate that BBI stimulates complex formation between EGFR, TP53 and MDC1 protein in wt. TP53 cells only. Since MDC1 is essential for recruitment of DNA repair foci, this observation may explain how BBI selectively stimulated repair of DNA double strand breaks in wt. TP53 cells.