Effects of leptin on sperm count and morphology in Sprague‐Dawley rats and their reversibility following a 6‐week recovery period

Altered epididymal sperm count and morphology following leptin treatment has been reported recently. This study examined the effects of 42 days of leptin treatment on sperm count and morphology and their reversibility during a subsequent 56‐day recovery period. Twelve‐week‐old male Sprague‐Dawley rats were randomised into four leptin and four saline‐treated control groups (n = 6). Intraperitoneal injections of leptin were given daily (60 μg Kg−1 body weight) for 42 days. Controls received 0.1 ml of 0.9% saline. Leptin‐treated animals and their respective age‐matched controls were euthanised on either day 1, 21, 42 or 56 of recovery for collection of epididymal spermatozoa. Sperm concentration was determined using a Makler counting chamber. Spermatozoa were analysed for 8‐hydroxy‐2‐deoxyguanosine and DNA fragmentation (Comet assay). Data were analysed using anova. Sperm concentration

Melatonin ameliorates the adverse effects of leptin on sperm

This study examined the effects of melatonin on leptin-induced changes in sperm parameters in adult rats. Five groups of Sprague-Dawley rats were treated with either leptin or leptin and melatonin or melatonin for 6 weeks. Leptin was given daily via the intraperitoneal route (60 μg kg− 1 body weight) and melatonin was given in drinking water (10 mg kg− 1 or 20 mg kg− 1 body weight per day). Upon completion, sperm count, sperm morphology, 8-hydroxy-2-deoxyguanosine, Comet assay, TUNEL assay, gene expression profiles of antioxidant enzymes, respiratory chain reaction enzymes, DNA damage, and apoptosis genes were estimated. Data were analyzed using ANOVA. Sperm count was significantly lower whereas the fraction of sperm with abnormal morphology, the level of 8-hydroxy-2-deoxyguanosine, and sperm DNA fragmentation were significantly higher in rats treated with leptin only. Microarray

The extent of PXE skin changes is related to cardiovascular complications and visual loss: a cross-sectional study

Pseudoxanthoma elasticum (PXE) is a genetic multisystem disorder with cutaneous, ophthalmological and cardiovascular (CV) involvement(1, 2, 3) . Having the capacity to predict the natural progression of PXE within various systems would improve preventive care in those patients at elevated risk of CV or ophthalmological complications. Yet, the means required to predict PXE progression are still lacking today. It is yet to be established whether each body system evolves at its own pace, however skin is typically involved earlier than other systems(4) . PXE skin lesions appear mainly in the first two decades of life; the initial manifestations are usually located at the neck and progressively extend to other skin areas. This extension is mostly over around 30 years old (y/o).(5) CV and ophthalmological complications may develop later. This article is protected by copyright. All rights reserved

Automated derivatization with o-phthalaldehyde for the estimation of amino acids in plasma using reversed-phase high performance liquid chromatography

322-325A fully automated method for quantitative estimation of plasma amino acids using fluorescence detection of o-phthaladehyde/2-mercaptoethanol derivatives of the analytes and their separation by gradient elution reversed-phase HPLC has been described. The method is simple and the three-step gradient elution is suitable for routine analysis of a large number of biological samples due to clear resolution, high degree of precision, accuracy, cost-effectiveness and lack of interference from chemical contaminations. Using this method, 19 amino acids were completely resolved and the within-run coefficients of variation ranged from 2.53 to 10.7% with a mean variation of 5.68%

Two-dimensional polymeric nanomaterials through cross-linking of polybutadiene-b-poly(ethylene oxide) monolayers at the air/water interface

Two-dimensional polymeric nanomaterials consisting of a continuously cross-linked polybutadiene (PB) two-dimensional network with poly(ethylene oxide) (PEO) domains of controlled sizes trapped within the PB network were synthesized. To reach that goal, novel (PB(Si(OEt)(3))-b-PEO)(3) star block copolymers were designed by hydrosilylation of the pendant double bonds of (PB-b-PEO)(3) star block copolymer precursors with triethoxysilane. The (PB(Si(OEt)(3))-b-PEO)(3) star block copolymers were characterized by H-1 NMR and IR spectroscopy. Self-condensation of the triethoxysilane pendant groups under acidic conditions led to a successful cross-linking of the polybutadiene blocks directly at the air/water interface without any additives or reagents. This strategy was found more efficient than radical cross-linking of (PB-b-PEO)(3) with AIBN to get a homogeneously cross-linked monolayer of controlled and fixed morphology as demonstrated by the easy mechanical removal of the cross-linked Langmuir film from the water surface. As shown by AFM imaging, this strategy allows the accurate control of the PEO "pore" size depending on the monolayer surface pressure applied during the cross-linking reaction. The subphase pH and surface pressure influence on the cross-linking kinetics and monolayer morphologies were investigated by Langmuir trough studies (isotherm and isobar experiments) and AFM imagin

Two-dimensional polymeric nanomaterials through cross-linking of polybutadiene-b-poly(ethylene oxide) monolayers at the air/water interface

Two-dimensional polymeric nanomaterials consisting of a continuously cross-linked polybutadiene (PB) two-dimensional network with poly(ethylene oxide) (PEO) domains of controlled sizes trapped within the PB network were synthesized. To reach that goal, novel (PB(Si(OEt)3)-b-PEO) 3 star block copolymers were designed by hydrosilylation of the pendant double bonds of (PB-b-PEO)3 star block copolymer precursors with triethoxysilane. The (PB(Si(OEt)3)-b-PEO)3 star block copolymers were characterized by 1H NMR and IR spectroscopy. Self-condensation of the triethoxysilane pendant groups under acidic conditions led to a successful cross-linking of the polybutadiene blocks directly at the air/water interface without any additives or reagents. This strategy was found more efficient than radical cross-linking of (PB-b-PEO)3 with AIBN to get a homogeneously cross-linked monolayer of controlled and fixed morphology as demonstrated by the easy mechanical removal of the cross-linked Langmuir film from the water surface. As shown by AFM imaging, this strategy allows the accurate control of the PEO pore size depending on the monolayer surface pressure applied during the cross-linking reaction. The subphase pH and surface pressure influence on the cross-linking kinetics and monolayer morphologies were investigated by Langmuir trough studies (isotherm and isobar experiments) and AFM imaging. © 2007 American Chemical Society

Cross-linking of polybutadiene at the air/water interface: Toward an easy access to two-dimensional polymeric materials

A novel approach to two-dimensionally crosslink polydienes at the air/water interface is proposed. The acid-catalyzed condensation of the triethoxysilane pendant groups of triethoxysilane-functionalized polybutadiene chains at the air/water interface successfully led to the formation of an insoluble crosslinked material which could be directly removed from the water surface. The efficiency of the cross-linking reaction was demonstrated through surface pressure measurements such as surface pressure-mean molecular area isotherms recorded at different reaction times and isobar experiments for different subphase pH values. The evolution of the monolayer topography during cross-linking was studied by atomic force microscopy imaging of the Langmuir-Blodgett films. (C) 2007 Elsevier Inc. All rights reserve

Cross-linking of polybutadiene at the air/water interface: Toward an easy access to two-dimensional polymeric materials

A novel approach to two-dimensionally crosslink polydienes at the air/water interface is proposed. The acid-catalyzed condensation of the triethoxysilane pendant groups of triethoxysilane-functionalized polybutadiene chains at the air/water interface successfully led to the formation of an insoluble crosslinked material which could be directly removed from the water surface. The efficiency of the cross-linking reaction was demonstrated through surface pressure measurements such as surface pressure-mean molecular area isotherms recorded at different reaction times and isobar experiments for different subphase pH values. The evolution of the monolayer topography during cross-linking was studied by atomic force microscopy imaging of the Langmuir-Blodgett films. © 2007 Elsevier Inc. All rights reserved