Allergic reactions to betalactams: studies in a group of patients allergic to penicillin and evaluation of cross-reactivity with cephalosporin

A group of 34 penicillin-allergic patients was studied to determine skin test reactivity to the different penicillins involved in inducing the allergic reaction and the cross-reactivity with side-chain-related and side-chain-unrelated cephalosporins. All the subjects selected for the study had to be skin test positive to at least one of the following determinants: benzyl-penicilloyl-polylysine (BPO-PLL), minor-determinant mixture (MDM), amoxicillin (AX), or ampicillin (AMP), or to possess in vitro IgE to the following conjugates: benzyl-penicilloyl-human-serum albumin (BPO-HSA), ampicilloyl-human-serum albumin (AMP-HSA), and amoxicilloyl-human-serum albumin (AX-HSA). Cephalexin (CE) and ceftazidime (CEF) were used to assess cross-reactivity. If skin tests to any of these compounds were positive, the patient was considered to be allergic; if negative, a challenge test was performed. Sixteen patients (47%) were skin test positive to BPO and/or MDM, and nine (26%) exclusively to AX and/or AMP. In three cases (8%), the RAST was positive although the skin test was negative; one to BPO-HSA and two to AX-HSA and AMP-HSA. Six patients (17%) needed to be challenged with the penicillin involved to establish the diagnosis. In five patients (14%), the skin tests were positive to CE and in none to CEF. In all the others, the skin tests were negative to both cephalosporins, and the patients tolerated the drugs when challenged. These results indicate the relevance of side-chain-specific minor determinants in betalactams allergy and provide support for the role of this chemical structure in the evaluation of cross-reactivity between penicillins and cephalosporins.     

Magnetostratigraphy of the Ahuachapán-Chipilapa geothermal field, El Salvador

The volcanic stratigraphy for the Ahuachapán-Chipilapa geothermal field is defined on the basis of the magnetostratigraphic results on 156 oriented samples from 33 sites. The magnetostratigraphic sequence shows that the major volcanism associated with the Concepción de Ataco caldera and the Cuyanausul volcano took place during the middle Brunhes chron (Quaternary). Pre-caldera activity of small centers such as Empalizada and Apaneca in the southern sector of the field occurred during the early Brunhes (0.77±0.07 Ma). Basaltic-andesitec activity associated with the Cuyanausul volcano took place earlier, i.e. during the Matuyama chron, possibly around 1.3±0.15 and 1.7±0.3 Ma.The local igneous basement is composed of Late Miocene-Pliocene andesites, ignimbrites and volcano-sedimentary deposits. Normal polarities and a K---Ar date of 7.37±0.73 Ma indicate that the volcanic activity in the study area extends beyond the Gauss chron. The polarity of some of the units in the post-caldera sequence and in the Concepción de Ataco and Cuyanausul sequences suggests that they may have recorded short polarity subchrons.     

Hydrodynamic water tunnel for characterization of hydrokinetic microturbines designs

Clean Technologies and Environmental Policy - The enormous inroads made by renewable energy in recent years have been the key to the development of new technologies designed to obtain energy from a...     

BTEK新科技导览中心，扎穆迪奥，比斯卡亚，西班牙

BTEK新科技导览中心被设计成为一座里程碑．一个景观的基准点。它由两座相互独立的金字塔式建筑物构成第一座整体呈黑色，由地面升起．体量较重，由3个金属立面构成．屋顶完全由太阳能板组成。     

Mechanical properties of natural fibers/polyamides composites

The aim of this investigation has been to use high performance thermoplastic matrices such as polyamides instead of the commonly used polyolefins to develop natural fiber composites for substituting glass fibers without renouncing to their mechanical properties. For this purpose, different natural fibers such as flax, jute, pure cellulose, and wood pulps have been melt compounded with different polyamides to analyze the effect of fiber content on mechanical properties. Fibers have not been treated as polyamides are less hydrophobic than polyolefins. Thermal behavior of the different fibers was determined by thermogravimetry to know the boundary for processing at high temperatures, since the melting points of the polyamides are much higher than those of polyolefins and this could lead to a higher degradation of the natural fibers. Rheological parameters were deduced by measuring torque values during the mixing process. Flexural and tensile modulus and strength of composites were analyzed, finding an increase in the mechanical properties compared with the unreinforced matrix that turns natural fibers into a considerable reinforcement offering a wealth of possibilities for industrial applications. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Upregulation of dynamin II expression during the acquisition of a mature pancreatic acinar cell phenotype

Members of the dynamin superfamily are GTPases which have been shown to support receptor-mediated endocytosis in vivo and bind to growth factor receptor-associated proteins in vitro. In acinar cells of the pancreas, receptor-mediated endocytosis is very important for the recycling of membranes after secretory granule release. Therefore, characterization of the molecular machinery responsible for this process is critical for a better understanding of this phenomenon. In this study we sought to determine the expression pattern of the endocytic GTPase dynamin II during pancreatic acinar cell differentiation in developing rat embryos and in dexamethasone-treated AR42J cells using Western blot, Northern blot, and immunocytochemical analyses. During pancreatic development, dynamin immunoreactivity is almost undetectable until day E17 but undergoes significant upregulation in acinar cells starting at E18. In addition, the levels of dynamin mRNA and protein in AR42J cells increase approximately threefold during dexamethasone-induced acinar differentiation. The increase in dynamin levels that occurs in both embryonic pancreatic cells and dexamethasone-treated AR42J cells correlates with the establishment of a more differentiated acinar phenotype. Therefore, these results suggest a potential role for dynamin in supporting receptor-mediated endocytosis in mature pancreatic acinar cells.     

Massenspektrometrischer Nachweis des cyclischen Trimeren im Polyäthylenterephthalat

By direct pyrolysis of commercial polyethyleneterephthalate in the mass spectrometer a content of about 1% of the cyclic trimer ethyleneterephthalate is indicated at temperatures below thermal degradation of the polymer. The comparison with EI- and FD-mass spectra of the authentic cyclic trimer allows its identification without previous isolation.     

Truncation-Driven Lateral Association of α-Synuclein Hinders Amyloid Clearance by the Hsp70-Based Disaggregase

The aggregation of α-synuclein is the hallmark of a collective of neurodegenerative disorders known as synucleinopathies. The tendency to aggregate of this protein, the toxicity of its aggregation intermediates and the ability of the cellular protein quality control system to clear these intermediates seems to be regulated, among other factors, by post-translational modifications (PTMs). Among these modifications, we consider herein proteolysis at both the N- and C-terminal regions of α-synuclein as a factor that could modulate disassembly of toxic amyloids by the human disaggregase, a combination of the chaperones Hsc70, DnaJB1 and Apg2. We find that, in contrast to aggregates of the protein lacking the N-terminus, which can be solubilized as efficiently as those of the WT protein, the deletion of the C-terminal domain, either in a recombinant context or as a consequence of calpain treatment, impaired Hsc70-mediated amyloid disassembly. Progressive removal of the negative charges at the C-terminal region induces lateral association of fibrils and type B* oligomers, precluding chaperone action. We propose that truncation-driven aggregate clumping impairs the mechanical action of chaperones, which includes fast protofilament unzipping coupled to depolymerization. Inhibition of the chaperone-mediated clearance of C-truncated species could explain their exacerbated toxicity and higher propensity to deposit found in vivo.