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Apparent Loss (apparent + loss)
Selected AbstractsNonepileptic Disorders Imitating Generalized Idiopathic EpilepsiesEPILEPSIA, Issue 2005Natalio Fejerman Summary:, Differential diagnosis between epileptic and nonepileptic paroxysmal disorders is fundamental not only to allow correct management of patients but also to avoid the burden of unnecessary antiepileptic medication. The focus of this chapter is limited to imitators of idiopathic generalized epilepsies (IGE) which are expressed through myoclonic, tonic,clonic, tonic, atonic, and absence seizures. Apparent losses of consciousness and drop attacks also have to be considered. Benign myoclonus of early infancy is the main nonepileptic disorder in the differential diagnosis of infantile spasms, but is not dealt with here because West syndrome is not an IGE. Hyperekplexia, metabolic disorders, hypnagogic myoclonus, and disturbed responsiveness caused by the use of drugs are listed in Table 1. Other conditions that may imitate more focal epileptic seizures are omitted. Benign neonatal sleep myoclonus, apnea and apparent life-threatening events in infants, cyanotic and pallid breath-holding spells, syncope, staring spells, psychogenic seizures, hyperventilation syndrome, and narcolepsy have been selected based on frequency or difficulties in differential diagnosis with the intention to cover the most conspicuous imitators of IGE in different ages. Table 1. Nonepileptic disorders imitating idiopathic generalized epilepsies [source] Co-option of endocytic functions of cellular caveolae by pathogensIMMUNOLOGY, Issue 1 2001J.-S. Shin Summary It is increasingly becoming clear that various immune cells are infected by the very pathogens that they are supposed to attack. Although many mechanisms for microbial entry exist, it appears that a common route of entry shared by certain bacteria, viruses and parasites involves cellular lipid-rich microdomains sometimes called caveolae. These cellular entities, which are characterized by their preferential accumulation of glycosylphosphatidylinositol (GPI)-anchored molecules, cholesterol and various glycolipids, and a distinct protein (caveolin), are present in many effector cells of the immune system including neutrophils, macrophages, mast cells and dendritic cells. These structures have an innate capacity to endocytoze various ligands and traffic them to different intracellular sites and sometimes, back to the extracellular cell surface. Because caveolae do not typically fuse with lysosomes, the ligands borne by caveolar vesicles are essentially intact, which is in marked contrast to ligands endocytozed via the classical endosome,lysosome pathway. A number of microbes or their exotoxins co-opt the unique features of caveolae to enter and traffic, without any apparent loss of viability and function, to different sites within immune and other host cells. In spite of their wide disparity in size and other structural attributes, we predict that a common feature among caveolae-utilizing pathogens and toxins is that their cognate receptor(s) are localized within plasmalemmal caveolae of the host cell. [source] Validation of daily increment formation in otoliths of juvenile and adult European anchovyJOURNAL OF FISH BIOLOGY, Issue 3 2003P. Cermeño The otoliths of juveniles and adults of European anchovy Engraulis encrasicolus held in aquaria were marked by immersion in oxytetracycline hydrochloride (OTC) at concentrations between 350 and 410 mg l,1 for 12 h. Counts of microincrements between fluorescent bands validated the daily otolith increment formation. The otolith increments were easily readable at ×400 with average increment widths of c. 1·1 µm. Validation was successfully demonstrated in juveniles and adults maintained for short periods in the aquaria in the summer. For European anchovy captured as juvenile and reared to adults, however, increment formation appeared less than daily. The daily periodicity of the otoliths in juvenile European anchovy implies that counting of microincrements can be used to study their birth dates. The application of this technique to adults, however, may lead to the underestimation of actual age and further research needs to be done to clarify the reasons for the apparent loss of the daily rhythm over long periods. [source] Synthesis of nitrogen-containing heterocycles 9,.JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2000- a][, Preparation, ]-triazolo[, ]triazine] derivatives, carbon-carbon bond cleavage of spiro[cycloalkane[, related compounds Diaminomethylenehydrazones of cyclic ketones 1,5 reacted with ethyl N -cyanoimidate (I) at room temperature or with bis(methylthio)methylenecyanamide (II) under brief heating to give directly the corresponding spiro[cycloalkane[1,,2,,4,]triazolo[1,,5,,- a][1,,3,-5,]triazine] derivatives 7,12 in moderate to high yields. Ring-opening reaction of the spiro[cycloalkanetriazolotriazine] derivatives occurred at the cycloalkane moiety upon heating in solution to give 2-alkyl-5-amino[1,2,4]triazolotriazines 13,16. Diaminomethylenehydrazones 17,19, of hindered acyclic ketones, gave 2-methyl-7-methylthio[1,2,4]-triazolo[1,5- a][1,3,5]triazines 21,23 by the reaction with II as the main products with apparent loss of 2-methylpropane from the potential precursor, 2- tert -butyl-2-methyl-7-methylthio[1,2,4]triazolo[1,5- a]-[1,3,5]triazines 20, in good yields. In general, bis(methylthio)methylenecyanamide II was found to be a favorable reagent to the one-step synthesis of the spiro[cycloalkanetriazolotriazine] derivatives from the diaminomethylenehydrazones. The spectral data and structural assignments of the fused triazine products are discussed. [source] Single-crystal X-ray and neutron powder diffraction investigation of the phase transition in tetrachlorobenzeneACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2006Charlotte K. Broder The polymorphic phase transition of 1,2,4,5-tetrachlorobenzene (TCB) has been investigated using neutron powder diffraction and single-crystal X-ray diffraction. The diffraction experiments show a reversible phase change that occurs as a function of temperature with no apparent loss of sample quality on transition between the two phases. Neutron powder diffraction gives detailed information on the molecular structural changes and lattice parameters from 2,K to room temperature. The structure of the low-temperature form has been elucidated for the first time using single-crystal X-ray diffraction. Comparison of the , and , structures show that they are both based on the same sheet motif, with the differences between the two being very subtle, except in terms of crystal symmetry. Detailed analysis of the structures revealed the changes required for inter-conversion. A computational polymorph search showed that these two sheet structures are more thermodynamically stable than alternative herringbone-type structures. [source] Fourier transform vibrational circular dichroism as a decisive tool for conformational studies of peptides containing tyrosyl residuesBIOPOLYMERS, Issue 1 2003Attila Borics Abstract Previous UV,circular dichroism (UV,CD) and NMR studies showed that Ac-AAAAAAAEAAKA-NH2 has an ,-helical structure in 50% (v/v) aqueous trifluoroethanol. Replacement of Ala1 to Ala6 with Tyr results in spectra that show an apparent loss of helicity in the same solvent. This apparent loss of helicity could be attributed to the coupling of the tyrosyl side chain chromophore with the backbone amide. However, such electronic coupling does not affect the vibrational CD (VCD) spectra. The VCD spectra of the peptides with tyrosyl residues were identical to that of the peptide containing no Tyr, which shows the same ,-helical structure. Because it is now clear that Tyr replacement does not change the backbone conformation of peptides, UV,CD measurements should be complemented by VCD to determine the secondary structure when electronic effects can disturb the UV,CD spectrum of the inherent structure. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 21,24, 2003 [source] Enantioselective Dihydroxylation of Alkenes Catalyzed by a PEG-Bound Bi-Cinchona Alkaloid LigandCHINESE JOURNAL OF CHEMISTRY, Issue 1 2005Xi-Wen Yang Abstract The recyclable PEG-bound bi-cinchona alkaloid ligand has been successfully applied to the homogeneous catalytic asymmetric dihydroxylation of various alkenes; good yields and excellent enantioselectivities were obtained. The ligand could be easily recovered and reused for 10 times without any apparent loss of its catalyst efficiency. [source] | |||||||||||||