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Silicone oil adherence to silicone IOLs after silicone oil removal is a known complication in pseudophakic patients. Droplet removal is difficult and may require IOL exchange. We describe two cases in which silicone oil droplets were observed early in the postoperative period in PMMA pseudophakic eyes and disappeared during silicone oil-fluid exchange--a phenomenon that has not been reported earlier in human PMMA pseudophakic eyes.

Presents a study which developed a fluid model to examine the equilibrium flow of electrons in the vacuum gap between the cathode and the plasma of a plasma opening switch. Dynamics of electron flow in the vacuum gap region; Review of electron trajectory method; Results of the simulation for different values of the switch parameters.

Subunit reassociation in mucin 1, a breast cancer tumor marker, is reported as one of the critical factors for its cytoplasmic activation. Inhibition of its heterodimeric association would therefore result in loss of its function and alter disease progression. The present study aimed at evaluating peptide inhibitor designing strategies that may serve as antagonist against this receptor-ligand alliance. Several peptides and their derivatives were designed based on native residues, subunit interface, hydrogen bonding and secondary structure. Docking studies with the peptides were carried on the receptor subunit and their binding affinities were evaluated using steered molecular dynamics simulation and umbrella sampling. Our results showed that among all the different classes of peptides evaluated, the receptor based peptide showed the highest binding affinity. This result was concurrent with the experimental observation that the receptor-ligand alliance in mucin 1 is highly specific. Our results also show that peptide ligand against this subunit association is only stabilized through native residue inter-protein interaction irrespective of the peptide structure, peptide length and number of hydrogen bonds. Consistency in binding affinity, pull force and free energy barrier was observed with only the receptor derived peptides which resulted in favorable interprotein interactions at the interface. Several observations were made and discussed which will eventually lead to designing efficient peptide inhibitors against mucin 1 heterodimeric subunit reassociation. [ABSTRACT FROM AUTHOR]

Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies. [ABSTRACT FROM AUTHOR]

New Zealand Ironsand (NZIS), an iron-rich sand ubiquitous to the coast of the North Island of New Zealand was examined for the removal of arsenic (both As (III) and As (V)) by adsorption. Batch experiments were performed to evaluate the adsorption kinetics at three different pH conditions (3.0, 7.5 and 11.0). In addition, a column test was conducted to obtain the breakthrough curve and appraise the arsenic removal capacity of NZIS used as a filter media. The kinetic study showed that a very long contact time (>144 h) was needed to reach equilibrium and the nature of the adsorption was well described (R2value more than 0.96 at each pH condition) with a pseudo–second-order adsorption kinetic model for both As (III) and As (V). In column tests, a pore volume (PV) of 700 and 400 yielded a total arsenic level less than the WHO guideline value of 10 μg/L for As (III) and As (V), respectively. [ABSTRACT FROM PUBLISHER]

Metal toxicity is a potential hazard to health and toxic effects of metals have been implicated in many diseases. Understanding the interaction of toxic metals becomes vital to prevent hazards following its association in living systems. Coordination chemistry helps in predicting the metal environments like coordinating residues, coordination space, metal coordination geometry, etc. Our work aimed at predicting the coordination of toxic metals arsenic, lead, and beryllium. In this work, we analyzed coordination for each metal from a set of arsenic, beryllium and lead bound structures which were retrieved from the Protein Data Bank. The structures were validated using B-factor and occupancy of the coordinating residues towards the metals. Coordination patterns such as chelate residues, chelate length, geometry, coordination number and structural architecture were predicted. Coordination geometry of the metals was exposed beyond the coordination space with their coordination number ranging from 2 to 11. Analysis of metal environment revealed the acidic amino acids aspartic acid, glutamic acid, and the basic amino acids lysine, histidine, and cysteine to be predominant in coordinating with the metals. Chelate patterns like DDVMITAK, DWNVTVK, ESGKNSS for beryllium, CCCSK, DSDWD for lead and FLICVI and LKHHKEE for arsenic were predicted to be common through extended coordination space. The distinct molecular geometries such as pentagonal bipyramid and square planar were observed only in lead bound structures but not in beryllium and arsenic bound structures. Beryllium had a larger influence than arsenic and lead, based on conformational changes owing to the presence of the metals. Our coordination study puts forth several propositions based on the metal environment that would help in designing chelation strategies. [ABSTRACT FROM AUTHOR]

Through their receptors, prostaglandins play crucial roles in various infections. Although prostaglandin E2 ( PGE2) is implicated as a susceptibility factor in Leishmania infection, the relative contributions of its four receptors - EP1, EP2, EP3 and EP4 - to this infection remain unknown. We report that Leishmania major infection of BALB/c-derived peritoneal macrophages up-regulated EP1 and EP3 expressions but down-regulated EP2 and EP4 expressions. EP2 and EP4 agonists reduced parasite load, but EP1 and EP3 agonists increased parasite load in macrophages in vitro. Agonists of EP2 and EP4, antagonists of EP1 and EP3, or lentivirally expressed EP1-sh RNA and EP3-sh RNA significantly reduced parasite burden in susceptible BALB/c mice. These novel data suggest differential regulation and counteractive functions of EP receptor subsets. [ABSTRACT FROM AUTHOR]

Cadmium toxicity has been reported to have major health effects including carcinogenicity, respiratory disorders, kidney failure, neurotoxicity and liver dysfunction. Understanding the nature of the association of cadmium with biomolecules has thus become imperative and a key factor in predicting the phenomena behind predisposition to disease. Accordingly, a computational investigation of cadmium-binding characteristics was performed using about 140 cadmium-bound structures and 34 cadmium-binding sequences. The metal-coordinating architecture defining the chelate loops, residue arrangement, secondary-structural characteristics, distances and angles were analyzed. Binding patterns were predicted based on the probability of occurrence of residues within the coordination distance and were further corroborated with sequence patterns obtained from cadmium-binding proteins. About 56 different chelate loops were identified. Based on these chelate loops, putative cadmium-binding patterns were derived that resembled short-length motifs, namely Y- X-G- X-G, Q- X9-E, E- X2-E- X2-E and T- X5-E- X2-E, which were observed within the conserved regions of the cadmium-binding proteins. The poorer conservation of residues around these motifs resulted in a deviating pattern against the coordination loops. These structure-based motifs are proposed to be an efficient tool in building chelators for the effective removal of cadmium. [ABSTRACT FROM AUTHOR]