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Purpose:To study the effect of cycloplegia on astigmatism measurements in pediatric patients with amblyopia.Methods:This was a prospective comparative clinical study. Participants 4 to 17 years old were recruited from the patient population at the Arkansas Children's Hospital eye clinic after informed consent was obtained. Autorefractor measurements were used to obtain values of refractive error in amblyopic and non-amblyopic patients before and after cycloplegia. The groups were subdivided into myopia and hyperopia and with and without underlying amblyopia. The refractive error was expressed as sphere, cylinder, axis of astigmatism, and spherical equivalent. The treatment effect was summarized as the mean difference (95% confidence interval) for each outcome.Results:No statistically significant difference was found on the axis and power of astigmatism before and after cycloplegia in the patients with amblyopia (No statistically significant difference was found on the axis and power of astigmatism before and after cycloplegia in the patients with amblyopia (P= .28 and .99, respectively).Conclusions:Non-cycloplegic autorefraction measurements may be considered safe for refining astigmatism power and axis in pediatric patients with amblyopia.[[J Pediatr Ophthalmol Strabismus. 2018;55(5):293-298.]

The UDP-glucuronosyltransferase UGT2B7 is an important human UGT isoform that catalyzes the conjugation of many endogenous and exogenous compounds, among them opioids, resulting in the formation of D-glucuronides. The binding site of the aglycone is located in the N-terminal half of the protein. In this study, we demonstrate that the opioid binding site in UGT2B7 is within the first 119 amino-terminal amino acids. Two maltose binding protein fusion proteins, 2B7F1 and 2B7F2, incorporating the first 157 or 119 amino acids, respectively, of UGT2B7 were expressed in Escherichia coli and purified by affinity chromatography. NMR spectroscopy using one-dimensional spectra, the inversion recovery method, and the transferred nuclear Overhauser effect spectroscopy was used to study the binding properties of opioids to the fusion proteins. Morphine was found to bind at a single site within the first 119 amino acids and to undergo a conformational change upon binding, as demonstrated by transferred nuclear Overhauser effect spectroscopy. Dissociation constants were obtained for morphine, naloxone, buprenorphine, and zidovudine, and the results were confirmed by equilibrium dialysis determinations. Two possible opioid binding sites, based on the nearest neighbors from opioid binding to the micro-receptor and to cytochrome 2D6, are proposed.

The effect of ADP-ribosylation of dinitrogenase reductase on its binding to dinitrogenase was investigated. Dinitrogenase reductase from Clostridium pasteurianum (Cp2) was a substrate for the ADP-ribosyltransferase and the dinitrogenase-reductase-activating glycohydrolase from Rhodospirillum rubrum. ADP-ribosylation inactivated Cp2 and prevented its formation of a tight complex with dinitrogenase from Azotobacter vinelandii (Av1). The complex between Cp2 and Av1 could not be ADP-ribosylated once it formed.

Abstract: The measurement of low-amplitude vibration of small mechanisms is a difficult problem. This paper presents the results of a study to develop a nonobtrusive optical method capable of producing quantitative analog outputs. The fruit of this work has been the development of a device denoted as a laser reflectometer which can detect rotations as small as 2 mgrrad and displacements on the order of 10–4 in. in the present configuration. The device was implemented in the analysis of read/write head motion upon a traveling floppy disk.

The virtual mass of a long, transversely vibrating tube submerged in a liquid was experimentally determined. The tube was surrounded by rigid tubes in a hexangular array and in square array, at pitch-to-diameter ratios from 1.25 to 1.5. The inertia coefficients observed were considerably larger than for a cylinder in an infinite volume of fluid, but smaller than one would compute assuming an annulus inscribed within the clear space around the vibrating tube. The results show the reduction of natural frequencies in a submerged tube bundle for one particular relative motion of tubes. Experimental results concerning the increase in damping due to the surrounding tubes are briefly indicated.

The enzyme that catalyzes the ADP-ribosylation and concomitant inactivation of dinitrogenase reductase in Rhodospirillum rubrum has been purified greater than 19,000-fold to near homogeneity. We propose dinitrogenase reductase ADP-ribosyltransferase (DRAT) as the working name for the enzyme. DRAT activity is stabilized by NaCl and ADP. The enzyme is a monomer with a molecular mass of 30 kDa and is a different polypeptide than dinitrogenase reductase activating glycohydrolase. NAD (Km = 2 mM), etheno-NAD, nicotinamide hypoxanthine dinucleotide, and nicotinamide guanine dinucleotide will serve as donor molecules in DRAT-catalyzed ADP-ribosylation reaction, and dinitrogenase reductases from R. rubrum, Azotobacter vinelandii, Klebsiella pneumoniae, and Clostridium pasteurianium will serve as acceptors. No other proteins or small molecules, including water, have been found to be effective as acceptors. Nicotinamide is released stoichiometrically with formation of the ADP-ribosylated product. DRAT is inhibited by NaCl and has maximal activity at a pH of 7.0.

The mechanism for "NH4+ switch-off/on" of nitrogenase activity in Azospirillum brasilense and A. lipoferum was investigated. A correlation was established between the in vivo regulation of nitrogenase activity by NH4Cl or glutamine and the reversible covalent modification of dinitrogenase reductase. Dinitrogenase reductase ADP-ribosyltransferase (DRAT) activity was detected in extracts of A. brasilense with NAD as the donor molecule. Dinitrogenase reductase-activating glycohydrolase (DRAG) activity was present in extracts of both A. brasilense and A. lipoferum. The DRAG activity in A. lipoferum was membrane associated, and it catalyzed the activation of inactive nitrogenase (by covalent modification of dinitrogenase reductase) from both A. lipoferum and Rhodospirillum rubrum. A region homologous to R. rubrum draT and draG was identified in the genomic DNA of A. brasilense as a 12-kilobase EcoRI fragment and in A. lipoferum as a 7-kilobase EcoRI fragment. It is concluded that a posttranslational regulatory system for nitrogenase activity is present in A. brasilense and A. lipoferum and that it operates via ADP-ribosylation of dinitrogenase reductase as it does in R. rubrum.

The configuration of read/write head designs in floppy disk drive units is of import as some designs witness vibration phenomena which lead to signal loss and excessive wearing of the disk media. This paper presents finite element modeling, and results thereof of a read/write head floppy disk system in free vibration. The objective of this work, of which this study marks but the beginning, is to determine the design parameters of read/write head support structure which will reduce the vibration phenomena.

Nitrogenase activity in the photosynthetic bacterium Rhodospirillum rubrum is reversibly regulated by interconversion of the Fe protein between a modified and an unmodified form. Since the discovery of the activation process in 1976, investigators have been unable to demonstrate the inactivation (modification) reaction in vitro. In this study, NAD-dependent modification and concomitant inactivation of the Fe protein were demonstrated in crude extracts of R. rubrum. Activation of the in vitro-modified Fe protein by activating enzyme and structural similarity between the in vivo and in vitro modifications are presented as evidence that the in vitro modification is the physiologically relevant ADP-ribosylation reaction. Using a partially purified preparation, we showed that the inactivating enzyme activity is stimulated by divalent metal ions and ADP, that O2-denatured Fe protein will not serve as a substrate, and that dithionite inhibits the modification reaction.

A scheme of eye/lens development suggested by Chanturishvili is described and compared with the ‘classical’ scheme of Spemann. A cine-micrographic examination of the ectodermal movements involved in neural tube formation in Triturus alpestris and an experimental embryological investigation of the process in Xenopus laevis provided data consistent with the classical scheme and irreconcilable with Chanturishvili’s suggestion that the whole eye/lens system originates as a single continuous anlage within the flat neural plate of Amphibia.

Report of an unusual case of Aicardi syndrome.