Neurofibrillary tangles and plaques are not accompanied by white matter pathology in aged triple transgenic-Alzheimer disease mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is the most common cause of dementia in aging populations. Although senile plaques and neurofibrillary tangles are well-established hallmarks of AD, changes in cerebral white matter correlate with cognitive decline and may increase the risk of the development of dementia. We used the triple transgenic (3xTg)-AD mouse model of AD, previously used to show that white matter changes precede plaque formation, to test the hypothesis that MRI detectable changes occur in the corpus callosum, external capsule and the fornix. T₂-weighted and diffusion tensor magnetic resonance imaging and histological stains were employed to assess white matter in older (11–17 months) 3xTg-AD mice and controls. We found no statistically significant changes in white matter between 3xTg-AD mice and controls, despite well-developed neurofibrillary tangles and beta amyloid immunoreactive plaques. Myelin staining was normal in affected mice. These data suggest that the 3xTg-AD mouse model does not develop MRI detectable white matter changes at the ages we examined.     

Stimulated by cyclodextrins high yield synthesis of azocrown analogues comprising pyrrole or imidazole residues

The influence of cyclodextrins (CDs) on the formation of azocrown ethers comprising pyrrole, imidazole and substituted imidazole has been studied. Pyrrole, imidazole, 2-methyl-, 4-methyl- and 4-phenylimidazole were coupled with bis-diazonium salts derived from bis-1,5-(2-aminophenoxy)-3-oxapentane or bis-1,8-(2-aminophenoxy)-3,6-dioxaoctane to form macrocyclic compounds with two azo units. The syntheses were performed under standard conditions in the presence of α-, β- or γ-CDs and the yield of the reaction products was compared with the results of plain experiments, i.e. without CDs. The results are discussed in terms of co-conformation of azole molecules embedded in CD cavity.

Pyrrole or imidazole or imidazole derivatives were coupled with bis-diazonium salts to form macrocycles with two azo units. The syntheses were performed under standard conditions in the presence of α-, β-, or γ-cyclodextrin and the yield of the reaction products was compared with the results of plain experiments, i.e. without CDs. The results are discussed in terms of co-conformation of azole molecules embedded in cyclodextrin cavity.     

A study on adsorption of metals by activated carbon in a large-scale (municipal) process of surface water purification

Elements that enter the aquatic environment may pose a health risk to wildlife and humans. The aims of this study were: to determine how the introduction of activated carbon for a water purification system will improve the quality of the water produced; and to investigate the sorption of metals on activated carbons, including determination of the accumulation, as well as changes in concentrations of elements in carbons. The tests were carried out on three types of activated carbons with different granular structure. All samples were collected from Water Treatment Plant Goczalkowice, Poland. Concentrations of elements were measured using an optical emission spectrometer with inductively coupled plasma. The experiment showed that metals accumulating in the activated carbons during the operation included: Ca, Mn, Zn, and Cu. In each of the three types of carbons, it can distinguish such elements as Ba, Al, Cr, Ni, Ti, which are characterized by irregular accumulation during the operation of the filter. The introduction of carbon sorbent for water treatment largely contributed to improvement in the quality of raw material supplied to customers, mainly with regard to taste and smell, as well as to reduction of basic parameters: color, absorbance in the UV range and oxidability.      

The temperature and concentration dependence of helical pitch in the mixtures of antiferroelectric compounds with the opposite helical twist sense

The temperature dependence of helical pitch for members of an homologous series of orthoconic antiferroelectric compounds (3FmHPhF) and their bicomponent mixtures (m = 3 and 5 as well as m = 3 and 7) has been measured by the method of selective light reflection. The compounds have the same chiral centre but they have different temperature dependence of the helical pitch as well as the helical twisting sense in SmC*_A phase: right for member m = 3, left for m = 7, and both right and left for m = 5. For this last homologue, the change of twisting sense is connected with the appearance of the unwound structure. Concentration dependence on helical pitch was investigated in the mixtures. It was demonstrated that it is possible to obtain mixtures with desirable high pitch and also with totally unwound structure.     

Helix parameters in bi- and multicomponent mixtures composed of orthoconic antiferroelectric liquid crystals with three ring molecular core

Eight types of bicomponent systems composed of antiferroelectric compounds with different polarity of achiral chain and different temperature dependence of helical pitch as well as three multicomponent mixtures composed of antiferroelectric compounds with opposite helical twist sense were studied. The phase miscibility was tested by polarising optical microscopy. The results of the helical pitch and helical twist sense measurements obtained by a spectrophotometric method of selectively reflected light and by polarimetric method, respectively, are presented. It was found that it is possible to control helical pitch length and temperature of helix twist inversion in antiferroelectric mixtures by controlling the ratio of compounds with left- and right-handed helix in such mixtures, although all of them have the same chiral terminal chain.     

Retention of configuration in the action of human plasma 3'-exonuclease on oligo(deoxynucleoside phosphorothioate). A new method for assignment of absolute configuration at phosphorus in isotopomeric deoxyadenosine 5'-O-[(18)O]phosphorothioate

A new method of analysis has allowed the exonucleolytic cleavage by human 3'-exonuclease to be determined. Hydrolysis by human plasma 3'-exonuclease proceeds with retention of configuration at phosphorus. The new method determines the sense of chirality at phosphorus in isotopomeric adenosine 5'-O-[(18)O]phosphorothioates. This is based on stereospecific two-step conversion of the mono-thionucleotide into the corresponding deoxyadenosine 5'-O-alpha-[(18)O]thiotriphosphate, followed by the use of terminal deoxyribonucleotidyl transferase and MALDI TOF mass spectrometry of the resulting elongated primer. Retention of configuration in the reaction of plasma 3'-exonuclease implies a two-step mechanism with two displacements on phosphorus. Inversion at each step leads to overall retention.     

Ultrastructure of Gentiana tibetica proembryogenic cells before and after cooling treatments

The influence of increased concentrations of sucrose, 0.4 M sorbitol, DMSO and vitrification solution (PVS2) on the ultrastructure of non-frozen and frozen suspensions of Gentiana tibetica King ex Hook. F.tissue cells was investigated. Embryogenic aggregates were composed of three groups of cells of different size with various types of plastids. The ultrastructural changes resulting from increasing the sucrose concentration in the medium from 3 to 6 percent for 4 weeks and from treatment with 0.4 M sorbitol for 48 h were similar. Observations showed replacement of large vacuoles by numerous small ones, condensation of cytoplasm, accumulation of starch, and fragmentation of endoplasmic reticulum. Treatment with PVS2 led to degradation of starch, coalescence of amyloplasts and to shrinking of nucleoli from the third group of cells when originating from 6 percent sucrose medium. The mitochondria initially had various shapes, but after PVS2 treatment showed only spherical shapes with sparse cristae. After programmed freezing of tissue protected by sorbitol and DMSO, lethal damage was observed: membrane and nuclei degradation, and cell destruction. Reversible changes after freezing were observed in tissue pretreated with vitrification solution: dilation of cell membranes, mitochondria with electron-lucent vessels, aggregation of numerous vesicles, and degradation of starch in amyloplasts. In cells cooled by a vitrification method, cell organelles appeared normal as early as 5 h after thawing, and anomalies were not observed after 48 h of post-thawing culture.