[Stage-appropriate treatment of keratoconus]. / Stadiengerechte Therapie des Keratokonus.

Keratoconus (KC) is a progressive cone-shaped corneal protrusion that causes paracentral thinning at the apex of the cone and typically occurs asymmetrically on both sides. After a careful anamnesis and classification of the degree of severity a targeted treatment appropriate to the stage of the disease is available. If the visual acuity is no longer sufficient, rigid gas-permeable contact lenses (CL) are fitted by a specialist. Riboflavin UVA cross-linking (CXL) is recommended in cases of progression and visual acuity that is still useful for the patient. Intracorneal ring segments (ICRS) are indicated for CL intolerance in cases of reduced visual acuity and a clear central cornea. If the stage is more advanced, deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PKP) is recommended. A PKP is contraindicated in acute KC but deep stromal sutures for readaptation of the Descemet tear with gas filling of the anterior chamber can considerably shorten the course. Almost no other eye disease is nowadays as easily accessible for an early instrument-based diagnosis and stage-appropriate treatment as KC.

[Coinfections in contact lens-associated mycotic keratitis with Pseudomonas or Acanthamoeba]. / Mischinfektionen bei kontaktlinsenassoziierter mykotischer Keratitis mit Pseudomonas oder Akanthamöben.

Contact lens-associated keratitis is becoming increasingly more frequent. Fungal keratitis is a relatively rare clinical picture but must be taken very seriously. Especially in the early stages of the disease, it may be clinically misdiagnosed and adequate treatment is therefore delayed. In treatment-resistant contact lens-associated fungal keratitis, coinfections or superinfections can occur. We present two patients with an initially unclear keratitis, in whom a fungal keratitis with coinfection of Pseudomonas aeruginosa and Acanthamoeba, respectively, could be confirmed. In both cases an urgent excimer laser penetrating keratoplasty with interrupted sutures and adequate local topical treatment for 8 weeks was successful.

ITSN1 regulates SAM68 solubility through SH3 domain interactions with SAM68 proline-rich motifs.

SAM68 is an mRNA-binding protein involved in mRNA processing in the nucleus that forms membraneless compartments called SAM68 Nuclear Bodies (SNBs). We found that intersectin 1 (ITSN1), a multidomain scaffold protein harboring five soluble SH3 domains, interacts with SAM68 proline-rich motifs (PRMs) surrounded by self-adhesive low complexity domains. While SAM68 is poorly soluble in vitro, the interaction of ITSN1 SH3 domains and mRNA with SAM68 enhances its solubility. In HeLa cells, the interaction between the first ITSN1 SH3 domain (SH3A) and P0, the N-terminal PRM of SAM68, induces the dissociation of SNBs. In addition, we reveal the ability of another SH3 domain (SH3D) of ITSN1 to bind to mRNAs. ITSN1 and mRNA may thus act in concert to promote SAM68 solubilization, consistent with the absence of mRNA in SNBs in cells. Together, these results support the notion of a specific chaperoning of PRM-rich SAM68 within nuclear ribonucleoprotein complexes by ITSN1 that may regulate the processing of a fraction of nuclear mRNAs, notably SAM68-controlled splicing events related to higher neuronal functions or cancer progression. This observation may also serve as a putative model of the interaction between other PRM-rich RBPs and signaling proteins harboring SH3 domains.

[Comparison of sterile donor tomography in the eye bank and graft tomography after penetrating keratoplasty]. / Vergleich der sterilen Spendertomographie in der Hornhautbank mit der Tomographie des Transplantates nach perforierender Keratoplastik.

BACKGROUND: Since 2018 we routinely use sterile donor tomography in the eye bank to avoid refractive surprises after keratoplasty. The purpose of this study was to compare donor tomography parameters measured with anterior segment optical coherence tomography (AS-OCT) with tomography parameters of the graft after penetrating keratoplasty (PKP). METHODS: This study enrolled 193 eye bank donor corneal tissues used for PKP (graft diameter 8.2 ± 0.7 mm). Preoperative measurements were taken using the AS-OCT Casia 2 (Tomey, Nagoya, Japan). The measurements were repeated postoperatively after 5 ± 4 months with all sutures in place and after 22 ± 4 months after removal of all sutures. Preoperative and postoperative values were compared using a Wilcoxon signed-rank test. RESULTS: Postoperatively, with all sutures in place (or without sutures), the dioptric power (P) at the anterior surface (a) of the cornea remained unchanged (-0.2 D, p = 0.78) (2.7 D bigger, p < 0.01) in the steep meridian (S) (PaS) and 4.5 D (2.8 D, p < 0.01) smaller in the flat meridian (F) (PaF) in comparison with the donor tomography values. The astigmatism (a) was 4.3 D (5.4 D, p < 0.01) bigger. At the posterior surface (p) the PpS was 0.9 D (0.9 D, p < 0.01) and PpF 0.3 D (p < 0.01) (0.1 D, p = 0.42) smaller, while the astigmatism (p) was 0.7 D (0.9 D) bigger (p < 0.01). The central corneal thickness was 55.7 µm (p < 0.01) (27.5 µm, p = 0.01) smaller. The total power of the transplant after removal of all sutures did not change significantly in comparison with the eye bank measurements. CONCLUSION: Central corneal thickness, dioptric power (P) and astigmatism all changed postoperatively compared to donor tomography values, except P at the steep meridian of the anterior corneal surface with all sutures in place and P at the flat meridian of the posterior corneal surface after removal of all sutures; however, the total power of the transplant after removal of all sutures did not change significantly. This information may be of value for IOL power calculation in the classical triple procedure.

NH3 biofiltration of piggery air.

An aboveground pilot-scale biofilter filled with wood chips was tested to treat ammonia emissions from a piggery located in Brittany (France). Two long-term tests ("summer" and "autumn" experiments) were carried out to improve biofilter applications for agriculture. The influence of climatic conditions on biofilter performance was taken into account. During summer 2012, the biofilter was operated for 74 days at different empty bed residence times (EBRTs) from 6 to 15 s. Inlet NH3 concentrations were relatively constant (around 15 mg m(-3)). Significant NH3 reductions were achieved at EBRT = 12 s (removal efficiencies, RE, ranged between 90 and 100% for loading rates, LR, of around 4 g m(-3) h(-1)). At a lower EBRT (6 s), RE dropped to roughly 30-50%. This was due to the dramatic increase in the loading rate (LR up to 12 g m(-3) h(-1)) but the results showed that the change in atmospheric conditions (temperature and relative humidity) also had a significant influence on biofilter performance. It was evidenced that the use of a humidifier upstream of the biofilter must be taken into account for large-scale biofilter design, but only for specific conditions (the spraying of the biofilter having to be carried out exceptionally). During autumn 2012, the biofilter was operated for 116 days at EBRT = 12 s. RE were around 80% for LR of around 3 g m(-3) h(-1). In such autumnal atmospheric conditions, a demister system should be installed upstream of the biofilter in order to avoid water accumulation in the bed material. Although biofiltration was suitable for NH3 treatment of piggery air, the need to control accurately the medium moisture content implies that biofilters would not be easily managed by a pig farmer.

Ion crater healing and variable temperature ellipsometry as complementary probes for the glass transition in thin polymer films.

Poly(methyl methacrylate) (PMMA) thin films of various tacticity and thickness were bombarded at grazing angles by 20 MeV Au ions at different temperatures. The shape of the tracks was investigated by scanning force microscopy (SFM) after annealing for various time at different temperatures and constant quenching rate. The thickness dependent glass transition temperature, T(g)(h), was estimated from the temperature of relaxation of ion-caused nanodeformations in the films. T(g)(h) obtained from the thermal healing of the holes and hillocks is found in good agreement with the one determined by variable temperature ellipsometry for PMMA film thickness of 80 nm and corresponds to the T(g) of each bulk PMMA stereoisomer. Below this thickness, some significant divergences are observed between the T(g) measured by the two techniques. We propose that the healing of ion crater hillock and the kink in the thermal expansion arise from the different nature of chains motions which are perturbed to different extents according to the main polymer chain preferential orientation in the thin film. This can be tentatively interpreted by a so-called "anisotropic" character of the glass transition.

Some relevant parameters affecting the glass transition of supported ultra-thin polymer films.

We have measured, the thickness dependence of the glass transition temperature T(g)( h), using ellipsometry at variable temperature, for poly(methyl-methacrylate) (PMMA) of various tacticity in confined geometry. We report that several factors significantly affect T(g)( h): i) polymer microstructure (stereoregularity of PMMA) related to local dynamics; ii) interfacial interactions; iii) conformation of the polymer chains. These results raise many fundamental questions on the origin of the thickness-dependent glass transition. Why and how do the interactions with the substrate significantly affect T(g)( h)? Does T(g)( h) depend on the modifications of conformational parameters of the chains (their entropy)? What is the correlation between local dynamics and T(g)( h) in thin films? The aim of this paper is to summarise these open questions, which should stimulate further investigations in the thin polymer film scientific community.

An efficient synthesis of a new series of acyclonucleosides starting from beta-amino alcohols.

A series of new acyclonucleosides analogues 3 has been synthesized very efficiently in three steps starting from beta-amino alcohols 1. The key step of this process is a nucleophilic substitution with various nucleophiles on 2,2'-anhydronucleosides 2. The chemo- and stereoselectivities of this reaction are discussed. AM1 calculations sustained the observed chemoselectivity.

Incorporation of 12(S)-hydroxyeicosatetraenoic acid into phospholipids and active diacylglycerols in rat liver epithelial cells: effects on DNA synthesis.

12(S)-Hydroxyeicosatetraenoic acid (12-HETE), the 12-lipoxygenase-derived metabolite of arachidonic acid, was incorporated into membrane phospholipids (PL) in various cells. PL are precursors of diacylglycerol (DAG), a protein kinase C (PKC) activator involved in cell-growth signaling. We studied 12-HETE incorporation into PL in non-transformed (NT-) and spontaneously transformed (T-) rat liver epithelial cells (RLEC), and its consequence on DNA synthesis. NT- and T-RLEC incorporated 12-HETE predominantly into phosphatidylcholine (PC). 12-HETE was incorporated at a greater rate, and with a higher phosphatidylethanolamine (PE)/PC ratio in T-cells. Preincubation of RLEC with 12-HETE at > or = 0.5 microM partially inhibited basal DNA synthesis in NT- and T-RLEC. Preincubation of NT-RLEC with 12-HETE (2.5 microM) also decreased bradykinin-stimulated DNA synthesis. Unstimulated RLEC produced 1-acyl-2-(12-HETE)DAG which was increased in NT-RLEC by bradykinin stimulation. Finally, 1-stearoyl-2-(12-HETE)DAG was as potent an in vitro PKC activator as 1-stearoyl-2-arachidonyl-DAG. These data demonstrate that 12-HETE incorporation into PL resulted in the production of active 12-HETE-containing DAG, together with reduced DNA synthesis.