An isopavine alkaloid from Thalictrum minus

A new alkaloid, isothalisopavine, was isolated from Thalictrum minus and shown to be 2,3,8-trimethoxy-7-hydroxyisopavine from spectral evidence. The known thalisopavine, from T. dasycarpum, is 2,3,8-trimethoxy-9-hydroxyisopavine. Isothalisopavine is the first of its class to be substituted unsymmetrically in the two aromatic rings.     

Urokinase-type plasminogen activator-induced monocyte adhesion is modulated by kininogen, kallikrein, factor XII, and plasminogen

Urokinase-type plasminogen activator (u-PA) was found to induce monocyte adhesion through a u-PA receptor (u-PAR)-mediated cAMP-dependent signal transduction pathway (J. Biol. Chem. 270, 30282-30285, 1995). In the present study, the effects of kininogen, kallikrein, factor XII, and plasminogen on u-PA-induced monocyte adhesion were examined since these proteins are abundant in plasma and closely related to u-PA in fibrinolysis and inflammation. Monocyte adhesion to a standard plastic surface by u-PA was shown to be inhibited by the activated, two-chain forms of kininogen (HKa) and kallikrein. The latter occurred only at higher, though physiological, concentrations and was dependent on its catalytic activity. Monocyte adhesion was promoted by factor XII and plasminogen via a noncatalytic mechanism. The findings indicated that u-PA-induced monocyte adhesion was downregulated by HKa and kallikrein and upregulated by factor XII and plasminogen at physiological concentrations. Therefore, these contact system proteins may be important modulators of u-PA-induced monocyte adhesion, a process which is involved in many pathophysiological events.     

Immunodeficiency, xanthomas and obstructive liver disease

Chronic obstructive liver disease and secondary hyperlipidemia developed in an immunodeficient boy. Sequential addition of cholestyramine and phenobarbital to his medical regimen, following an initial response to bile drainage, resulted in the disappearance of xanthomas and pruritus, and the restoration of normal serum concentrations of lipids and bile acids. This improvement may result from shifting the bile acid pool from the peripheral blood compartment to the enterohepatic circulation.     

Canine leishmaniasis with amyloidosis

Visceral leishmaniasis was diagnosed in a 2-year-old male Great Dane imported from Greece. The clinical signs included anemia, diarrhea, weight loss, proteinuria, and hyperglobulinemia with increases in alpha2- and gamma-regions. At necropsy there was plasma-lymphocytic and macrophage infiltration of spleen, macrophage infiltration of bone marrow, intracellular organisms of macrophages having the ultrastructural characteristics of Leishmania species, and severe amyloidosis of the spleen, liver, and kidney.     

Breast cancer. Relationship to thyroid supplements for hypothyroidism

This study was undertaken to determine the relationship between thyroid supplements and breast cancer. The incidence of breast cancer among the patients who received thyroid supplements was 12.13%, while in the control group it was 6.2%. The incidence rate of breast cancer was 10%, 9.42%, and 19.48% among patients who received thyroid supplements for one to five, 5 to 15, and for more than 15 years, respectively. The incidence of breast cancer among nulliparous women who received thyroid supplements was 33%, while in the nulliparous women without thyroid supplements the incidence was only 9.25%. Even in a specific age group, the incidence rate of breast cancer was higher among patients receiving thyroid supplements, when compared to the control patients in the same age group.     

Morphology,rheology and mechanical properties of polypropylene/ethylene–octene copolymer/clay nanocomposites: Effects of the compatibilizer

The objective of this study was to investigate the effects of two compatibilizers, namely maleated polypropylene (PP-g-MA) and maleic anhydride grafted poly (ethylene-co-octene) (EOC-g-MA), on the morphology and thus properties of ternary nanocomposites of polypropylene (PP)/ethylene–octene copolymer (EOC)/clay nanocomposite. In this regard the nanocomposites and their neat polymer blend counterparts were processed twice using a twin screw extruder. X-ray diffraction, transmission electron microscopy, Energy dispersive X-ray spectroscopy, and scanning electron microscopy were utilized to characterize nanostructure and microstructure besides mechanical and rheological behaviors of the nanocomposites. Clay with intercalated structure was observed in EOC phase of the PP/EOC/clay nanocomposite. Better dispersion state of the intercalated clay in EOC phase was observed by adding EOC-g-MA as a compatibilizer. On the other hand, adding PP-g-MA resulted in migration of the intercalated clay from the EOC to the PP and to the interface regions. It was also demonstrated that the elastomer particles became smaller in size where clay was present. The finest and the most uniform morphology was found in the PP/EOC/clay nanocomposite. In addition, the rheological results illustrated a higher complex viscosity and storage modulus for PP/EOC/PP-g-MA/clay nanocomposite in which clay particles were present in the matrix. Mechanical assessments showed improvements in the toughness of the nanocomposites with respect to their neat blends, without significant change in stiffness and tensile strength values. These results highlight a toughening role of clay in the polymer blend nanocomposites studied.     

Modulating the mechanical properties of photopolymerised polyethylene glycol–polypropylene glycol hydrogels for bone regeneration

Hydrogels formulated from single polymers are often insufficient in terms of their mechanical properties for use as bone substitute materials. Hence, hydrogels synthesised from combinations of polymers have been investigated to optimise the performance of such materials. In the current study, polypropylene glycol dimethacrylate was added to polyethylene glycol dimethacrylate of a variety of molecular weights and photopolymerised to form a series of hydrogels. Polyethylene glycol and polypropylene glycol have the same chemical structure with the exception of a methyl group on the later. Herein, the influence of the methyl group of polypropylene glycol on the mechanical properties of hydrogels for bone regeneration applications is reported. For both unconfined and cyclic compression testing, results demonstrated that the incorporation of PEGDMA into the precursor improves the compression strength of the hydrogels. For example, in unconfined compression tests the Young’s modulus varied between 6.62?±?0.31?MPa and 8.08?±?0.81?MPa with the incorporation of PEGDMA 400.     

Investigation of the influence of freeze-thaw processing on the properties of polyvinyl alcohol/polyacrylic acid complexes

Physically crosslinked poly (vinyl alcohol)/poly (acrylic acid) hydrogels were prepared by freeze thaw processing. The hydrogels were formed in, either, water or a water/DMSO mixture and the chemical, mechanical, and thermal properties were determined by FTIR analysis, rotational rheometry and modulated DSC respectively. The results indicate that the hydrogels containing DMSO are significantly stronger than those containing water alone at temperatures between 20 and 40°C. Materials with different characteristics can be created by varying the solvent and the polymer feed ratios. DSC analysis indicated that thermal transitions are present at temperatures that may make these hydrogels useful in temperature sensitive drug delivery systems.     

In vitro degradation and drug release from polymer blends based on poly(<Emphasis Type="SmallCaps">dl</Emphasis>-lactide), poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactide-glycolide) and poly(ε-caprolactone)

Bioresorbable materials are extensively used for a wide range of biomedical applications. Accurately modifying and evaluating the degradation rate of these materials is critical to their performance and the controlled release of bioactive agents. The aim of this work was to modify the physical properties, degradation rate and drug delivery characteristics of thin films for medical applications by blending poly(dl-lactic acid) (PDLLA), poly(l-lactide-co-glycolide) (PLGA) and poly(ε-caprolactone) (PCL). The thin films were prepared using solvent casting and compression moulding and the in vitro degradation study was performed by immersing the films in a phosphate-buffered saline at elevated temperature for a period of 4 weeks. The degradation rate of the materials was analysed by differential scanning calorimetry, tensile testing and weight loss studies. The thermal analysis of the blends indicated that the presence of PLGA or PDLLA in the film resulted in increased degradation of the amorphous regions of PCL. It was observed that the samples consisting of PDLLA with PCL demonstrated the greatest weight loss. The decrease in mechanical properties observed for both sets of polymer blends proved to be similar. The solvent cast technique was selected as the most appropriate for the formation of the polymer/drug matrices, due to the potentially adverse thermal processing effects associated with compression moulding. It was found that modulation of drug release was achievable by altering the ratio of PCL to PDLLA or PLGA in the thin film blends.