The Hierarchy of Proinflammatory Cytokines in Ocular Inflammation.

PURPOSE: The concept of tissue-dependent cytokine hierarchy has been demonstrated in a number of diseases, but it has not been investigated in ophthalmic diseases. Here, we evaluated the functional hierarchy of interleukin-1ß (IL-1ß), IL-6, IL-17A, and tumor necrosis factor (TNF) in the induction of ocular inflammation. MATERIALS AND METHODS: We delivered adeno-associated virus (AAV) vectors expressing IL-1ß, IL-6, IL-17A, or TNF intravitreally in naïve C57/BL6 mice and compared and contrasted the inflammatory effects in the eye 5 weeks after AAV-mediated gene transfer. We also used an in vitro human system to test the effect of cytokines on barrier function. RESULTS: We found that IL-1ß had the highest ability to initiate ocular inflammation. The continuous overexpression of IL-1ß resulted in a significant upregulation of additional proinflammatory mediators in the eye. Using scanning laser ophthalmoscope and optical coherence tomography imaging techniques, we showed that a low dose of AAVIL-1ß was sufficient and was as pathogenic as a high dose of TNF in inducing vascular leakage, retinal degeneration, and cellular infiltration. Furthermore, only a marginal increase in IL-1ß was enough to cause cellular infiltration, thus confirming the highly pathogenic nature of IL-1ß in the eye. Contrary to our expectation, IL-6 or IL-17A had minimal or no effect in the eye. To examine the clinical relevance of our findings, we used an impedance assay to show that IL-1ß alone or TNF alone was able to cause primary human retinal endothelial cell barrier dysfunction in vitro. Again, IL-6 alone or IL-17A alone had no effect on barrier function; however, in the presence of IL-1ß or TNF, IL-17A but not IL-6 may provide additive proinflammatory effects. CONCLUSIONS: Our studies demonstrate the existence of a functional hierarchy of proinflammatory cytokines in the eye, and we show that IL-1ß is the most pathogenic when it is continuously expressed in the eye.

A novel technique in airway management of neonates with occipital encephalocele.

Airway stabilization in neonates with occipital encephalocele (OE) is critical during surgery or if they develop hypoxic-respiratory failure. Endotracheal intubation can be challenging due to difficulty in positioning the head in a patient with large occipital mass. We describe a novel technique for positioning neonates with large OE using a commonly used hospital apparatus which facilitated appropriate positioning of the baby and successful endotracheal intubation with ease and no additional staff.

[Biomechanical characteristics of human fetal membranes. Preterm fetal membranes are stronger than term fetal membranes]. / Biomécanique de la rupture des membranes fœtales. Les membranes fœtales sont plus résistantes avant terme qu'à terme.

The purpose of this study was to determine the biomechanical characteristics of human fetal membranes (FM) throughout gestation. Biomechanical properties were determined for 115 FM of 23-41 weeks gestation using our previously described methodology. The areas of membrane immediately adjacent to the strongest and weakest tested spots were sampled for histomorphometric analysis. Clinical data on the patients whose FM were examined were also collected. FM less than 28 weeks gestation were associated with higher incidence of abruption and chorioamnionitis. Topographically FM at all gestations had heterogeneous biomechanical characteristics over their surfaces with distinct weak areas. The most premature membranes were the strongest. FM strength represented by rupture force and work to rupture decreased with increasing gestation in both weak and strong regions of FM. This decrease in FM strength was most dramatic at more than 38 weeks gestation. The FM component amnion-chorion sublayers were thinner in the weak areas compared to strong areas. Compared to term FM, preterm FM are stronger but have similar heterogeneous weak and strong areas. Following a gradual increase in FM weakness with increasing gestation, there is a major drop-off at term 38 weeks gestation. The FM weak areas are thinner than the stronger areas. Whether the difference in thickness is enough to account for the strength differences is unknown.

The effects of thrombin and cytokines upon the biomechanics and remodeling of isolated amnion membrane, in vitro.

Abruption-induced thrombin generation and inflammation/infection induced cytokine production have both been associated with fetal membrane (FM) weakening and preterm premature rupture of the fetal membranes (PPROM). Using our in vitro model system we have demonstrated that thrombin, and separately the cytokines, tumor necrosis factor-alpha (TNFα) and interleukin-1-beta (IL-1ß), remodel and weaken full thickness FM. Additionally, we have reported that the anti-oxidant and NFκB inhibitor, alpha-lipoic acid (LA), blocks these thrombin and cytokine induced effects. The purpose of these studies was to determine whether thrombin and cytokines directly weaken the amnion membrane (AM), the major load-bearing component of FM. Isolated AM or full thickness FM fragments from unlabored Cesarean deliveries were incubated with thrombin, TNFα, or IL-1ß, for 48 h. Rupture strength (breaking force) of each fragment was thereafter determined using our published methodology. Biochemical evidence of remodeling and apoptosis; immunoreactive Matrix Metalloproteinase 9 (MMP9), Tissue Inhibitor of Matrix Metalloproteinase 3 (TIMP3) and cleaved poly (ADP-ribose) polymerase (C-PARP) levels in tissue extracts, were determined by western blot and densitometry. Thrombin induced a dose-dependent weakening of isolated AM (P < 0.001) coupled with dose dependent increases in PARP cleavage, and reciprocal increases and decreases, respectively, in MMP9 and TIMP3 protein (all P < 0.01). Thrombin receptor activating peptide-6 (TRAP) also weakened isolated AM. Neither TNFα nor IL-1ß weakened isolated AM. However, both cytokines weakened AM when it was incubated together with the choriodecidua as part of full thickness FM (P < 0.001). Cytokine-conditioned choriodecidua medium also weakened isolated AM (P < 0.001). Under conditions in which cytokines weakened the AM, the changes in MMP9, TIMP3 and PARP cleavage were consistent with those seen after thrombin incubation. LA blocked the FM weakening and remodeling effects. In summary, thrombin weakens AM directly whereas cytokines weaken AM indirectly by causing the release of soluble intermediates from the choriodecidua.

Alpha-lipoic acid inhibits thrombin-induced fetal membrane weakening in vitro.

Cytokine-mediated inflammation and abruption-induced thrombin generation are separately implicated in matrix metalloproteinase (MMP)-mediated weakening of fetal membranes (FM) leading to preterm premature rupture of the fetal membranes (PPROM). At term, FM of both labored vaginal and unlabored Cesarean deliveries exhibit a weak zone overlying the cervix exhibiting ECM remodeling characterized by increased MMP9 protein and activity. We have reproduced these biochemical changes as well as FM weakening in vitro using tumor necrosis factor-alpha (TNF) and interleukin (IL)-1ß, inflammatory cytokines implicated in PPROM. Additionally, we have reported that the antioxidant and NFκB inhibitor alpha-lipoic Acid (LA) blocks these TNF-induced effects. We now present the first direct evidence that thrombin also can induce FM weakening in vitro, and LA treatment inhibits this thrombin-induced-weakening. Full thickness FM fragments from unlabored Cesarean deliveries were incubated with increasing doses of thrombin (0-100 u/ml) for 48 h. Fragments were then strength tested (breaking force and work to rupture) using our published methodology. MMP3 and 9 levels in tissue extracts were determined by Western blot and densitometry. To determine the effect of LA, FM fragments were incubated with control medium or 10 u/ml thrombin, with or without 0.25 mM LA. Strength testing and MMP induction were determined. Thrombin induced a dose-dependent decrease in FM strength (42% baseline rupture force and 45% work to rupture) coupled with a dose-dependent increase in MMP3 and 9 expression (all p < 0.001). Treatment of FM with 0.25 mM LA completely inhibited thrombin-induced FM weakening and MMP expression (all p < 0.001). Thrombin treatment of cultured FM induces mechanical weakening and increased MMP3 and 9. Treatment of FM with LA inhibits these thrombin-induced effects. We speculate LA may prove clinically useful in prevention of PPROM associated with abruption.

Screening of pollen grains vis-à-vis whole plants of oilseed brassicas for tolerance to salt.

Pollen grains and whole plants of 11 cultivars of oilseed brassicas (B. juncea,B. campestris,B. carinata) were screened for salt tolerance. Whereas pollen germination percentage in sitting drop cultures served as a reliable index of pollen tolerance to NaCl, pollen-tube growth did not. Seed yield in plants of the same 11 cultivars raised in artificially salinized soils also proved to be a good index of whole plant tolerance to soil salinity. A close correspondence between pollen (gametophyte) and whole plant (sporophyte) responses to salinity was discovered. Our studies show that tolerance to salt is yet another trait expressed in both the sporophyte and gametophyte.

Formation of plantlets through somatic embryogeny in the Himalayan blue poppy, Meconopsis simplicifolia (Papaveraceae).

Exuberant and subculturable calli could be induced from only hypocotyl and leaf segments of ca 4-month-old seedlings of Meconopsis simplicifolia cultured on Murashige & Skoog's medium supplemented with 10(-6)M kinetin + 10(-5)M α -naphthalene acetic acid. Suspension cultures were initiated from the calli in a similar medium but with 10(-5)M 2,4-dichlorophenoxy acetic acid in place of α -naphthalene acetic acid. In ca 80% of the suspension cultures somatic embryos differentiated freely (80-85%) as well as on the surface of small clumps of tissue (15-20%). Somatic embryos that developed beyond heart-shaped stage were transferred to agar-solidified Murashige & Skoog's medium free of growth substances. When maintained in 10 h light and 14 h dark the somatic embryos developed into plantlets bearing cauline leaves. From seed sowing to raising normal plantlets via callus required 28 weeks; on average 80 plantlets were obtained from one explant in three passages.