DYRK1A kinase inhibitors with emphasis on cancer

Various types of cancers (including gliomas, melanomas, and esophageal, pancreas and non-small-cell lung cancers) display intrinsic resistance to pro-apoptotic stimuli, such as conventional chemotherapy and radiotherapy, and/or the activation of a multidrug resistance phenotype, which are major barriers to effective treatment and lead to poor patient prognosis. The DYRK1A kinase is directly implicated in the resistance of cancer cells to pro-apoptotic stimuli and drives several pathways that enhance proliferation, migration, and the reduction of cell death, leading to very aggressive biological behavior in cancer cell populations. The DYRK1A kinase is also implicated in neurological diseases and in neoangiogenic processes. Thus, the DYRK1A kinase is of great interest for both cancer and neuroscience research. During the last decade, numerous compounds that inhibit DYRK1A have been synthesized. The present review discusses the available molecules known to interfere with DYRK1A activity and the implications of DYRK1A in cancer and other diseases and serves as a rational analysis for researchers who aim to improve the anti-DYRK1A activity of currently available compounds.

Characterisation of ferromagnetic rings for Zernike phase plates using the Aharonov-Bohm effect

Holographic measurements on magnetised thin-film cobalt rings have demonstrated both onion and vortex states of magnetisation. For a ring in the vortex state, the difference between phases of electron paths that pass through the ring and those that travel outside it was found to agree very well with Aharonov-Bohm theory within measurement error. Thus the magnetic flux in thin-film rings of ferromagnetic material can provide the phase shift required for phase plates in transmission electron microscopy. When a ring of this type is used as a phase plate, scattered electrons will be intercepted over a radial range similar to the ring width. A cobalt ring of thickness 20 nm can produce a phase difference of π/2 from a width of just under 30 nm, suggesting that the range of radial interception for this type of phase plate can be correspondingly small.

[Pini cembrae coni: histo-anatomical and chemical studies, assessment of antioxidant activity]

This study aimed to identify some histoanatomical features, to evaluate the polyphenolic content and antioxidant activity of cembran pine female cones.

MATERIAL AND METHODS

The cross sections, obtained by usual techniques, were examined using a Novex microscope with a Canon A95 digital camera. For chemical and antioxidant assays dried cones were extracted with 80% aqueous methanol. The total phenolics, flavonoids and proanthocyanidins in cone extract were quantified by spectrophotometric methods. The antioxidant activity was investigated using different in vitro assays: ABTS radical cation scavenging assay, reducing power assay and ferrous ion chelating ability assay.

RESULTS

The histo-anatomical study of the seed-bearing scale revealed many secretory channels. The cone extract had low contents of total phenolics (48.03 +/- 0.10 mg/g), flavonoids (8.11 +/- 0.27 mg/g) and proanthocyanidins (1.63 +/- 0.03 mg/g). The extract scavenged ABTS radical cation and reduced ferric ions to ferrous ions with EC50 values of 64.6 +/- 0.8 and 118.60 +/- 1.89 microg/ml, respectively being less active than the positive control, quercetin (EC50 = 1.16 +/- 0.05 and 2.58 +/- 0.00 microg/ml, respectively). In ferrous ion chelating ability assay the extract showed a good activity (EC50 = 1.2 +/- 0.0 mg/ml) while quercetin was inactive.

CONCLUSIONS

The ability of cone extract to chelate ferrous ions encourages further studies for identification of bioactive constituents and evaluation of their protective effects against ferrous ion-induced oxidative stress.

Multimodality imaging of exuberant mitral annular calcification in a patient presenting with transient ischaemic attack

We report an unusual case of calcification of mitral valve annulus imaged with multiple non-invasive modalities in a patient who suffered a transient ischaemic attack, probably from thrombus overlying the mitral annular calcification. Both this mode of presentation and the imaging features of the annular calcification were relatively unusual, and the images obtained are remarkably clear and diagnostic.

On the corrosion and soiling effects on materials by air pollution in Athens, Greece

Abstract. In the frame of the European project, entitled MULTI-ASSESS, specimens of structural metals, glass, stone and concrete materials were exposed to air pollution at a station, which was installed for this purpose on a building, located in the centre of Athens. The main purpose of this project was to determine the corrosion and soiling effects of air pollution on materials. A set of the specimens was exposed in a position that was sheltered from rain and partly from wind, and another set was exposed in unsheltered positions on the roof of the above said building. In addition, other specimens were exposed at different heights on the same building, in order to investigate for the first time the corrosion and soiling effects on various materials as a function of height. For the determination of these effects, chemical analysis of the specimens was performed and basic parameters as the weight change, the layer thickness and the optical properties were calculated. Finally, the results obtained are discussed and their plausible interpretation is attempted.

Detection of endogenous magnetic nanoparticles with a tunnelling magneto resistance sensor

The magnetotactic bacterium Magnetospirillum sp. has been cultured and the properties of its endogenous magnetic nanoparticles characterized. Electron-microscopic analyses indicate that the endogenous magnetite nanoparticles in Magnetospirillum sp. are coated with a 3-4 nm thick transparent shell, forming a magnetosome. These magnetite nanoparticles had diameters of 50.9+/-13.3 nm, in good agreement with the diameter of 40.6+/-1.2 nm extracted from magnetometry. Each Magnetospirillum sp. bacterium contained chains of 5-25 magnetosomes. Superconducting quantum interference device magnetometry results indicate that the extrinsic superparamagnetic response of the bacterial solution at room temperature can be attributed to the reversal of the magnetization by physical rotation of the nanoparticles. The intrinsic blocking temperature of a sample of freeze-dried bacteria was estimated to be 282+/-13 K. A tunnelling magneto resistance sensor was used to detect the stray fields of endogenous magnetic nanoparticles in static and quasi-dynamic modes. Based on the tunnelling magneto resistance sensor results, the magnetic moment per bacterium was estimated to be approximately 2.6 x 10(-13) emu. The feasibility of this detection method either as a mass-coverage device or as part of an integrated microfluidic circuit for detection and sorting of magnetosome-containing cells was demonstrated.

Dose-response function for the soiling of silica-soda-lime glass due to dry deposition

Several exposure campaigns of silica-soda-lime window glass have been performed in 30 European sites and 1 in Canada in order to understand, quantify and model the phenomenon of soiling. In this purpose samples were exposed sheltered from the rain. Parallel to exposure, several meteorological parameters and pollution concentrations have been monitored. This paper shows first results on the establishment of a dose-response function for glass soiling. Statistical analyses show that PM(10) is not the only parameter, but also SO(2) and NO(2) atmospheric concentrations seem to be responsible for the optical impairment of glass surfaces, expressed as haze.

Antibacterial activity of some Artemisia species extract

The antimicrobial activities of ethanol, methanol and hexane extracts from Artemisia absinthium, Artemisia annua and Artemisia vulgaris were studied. Plant extracts were tested against five Gram-positive bacteria, two Gram-negative bacteria and one fungal strain. The results indicated that Artemisia annua alcoholic extracts are more effective against tested microorganisms. However, all plants extracts have moderate or no activity against Gram-negative bacteria. The obtained results confirm the justification of extracts of Artemisia species use in traditional medicine as treatment for microbial infections.

The pocket echocardiograph: a useful new tool?

AIMS

Hand-carried ultrasound scanners are getting smaller. The Acuson P10 is the latest and smallest portable echocardiograph available on the market.

METHODS AND RESULTS

We tested the ability of this scanner to allow qualitative assessment of LV size and function in an unselected group of 30 patients [19 male, 11 female; mean age (SD) 64.7 (10.3) years] seen by a consultant cardiologist (accredited for advanced echocardiography) during a week on call in a regional cardiac tertiary facility. Patients had focused scans (parasternal long-axis and apical four chamber views) for a maximum of 4 min, and an assessment of LVEF (normal/abnormal) and LV dimension (LVD) (dilated/non-dilated) was recorded. Where available, this was compared with results of alternative imaging modalities. In 23 (77%) patients, it was possible to assess LVEF and LVD; of these, 19 (83%) had alternative imaging techniques, which confirmed the findings. It was possible to obtain a parasternal long-axis image in 28 (93%) patients and apical four-chamber views in 23 (77%). Clinical management was altered by the findings of the portable scan in two patients.

CONCLUSION

The 'pocket scanner' allows accurate qualitative assessment of left ventricular dimensions and function in a substantial proportion of patients seen in tertiary cardiology practice.

Modelling of the calcareous stone sulphation in polluted atmosphere after exposure in the field

Parisian Lutetian and Val-de-Loire Turonian Richemont limestone tablets were exposed, sheltered and unsheltered from rain, for up to 3 years in Paris and Tours, respectively. Sulphur concentrations below the stone surfaces were measured from powders obtained by milling the stone in successive steps of 0.1 mm. In tablets exposed to rain, measured sulphur concentration remains equal to the stone background concentration, implying that the sulphur deposited between rain events is leached by the next event. In contrast, in tablets sheltered from rain, the sulphur concentration in the first layer below the stone surface increases non-linearly with time. Sulphation does not, however, penetrate more than 0.2 mm. A sigmoidal Hill curve provides a good fit with changes in measured sulphur concentration over time within the first layer of each sheltered stone. This model reveals a cumulative phenomenon of sulphation, characterized by a saturation level that obstructs deeper penetration of sulphur within the stone. The model shows the same type of time evolution of sulphation for both stones, but with different coefficients; these coefficients are related to the atmospheric environment of exposure and to the different intrinsic properties of each stone.

Modeling of soiling based on silica-soda-lime glass exposure at six European sites

Samples of silica-soda-lime float glass, a material selected as a pertinent soiling sensor, were exposed for up to 28 months at four urban sites (Athens, Krakow, London and Prague) and at a semi-urban one (Monte Libretti, near Rome), sheltered from rain. This exhaustive experience permitted to complete and to test the generalisation ability of the results previously obtained on the same material, exposed according to the same protocol, during 24 months, at a single site (Paris). The model previously fitted for the Paris experiment, the Hill equation, could be successfully generalised for four other sites of exposure (Athens, Krakow, Prague and Rome). The analytical form of this model was interpreted in terms of a physical description of the soiling phenomenon. Some of the model coefficients were different from one site to another, depending on the specific environment of exposure (air pollution levels, meteorological factors), while the other ones were rather equivalent. The analysis of the model coefficients, on the one hand, led to an estimation of the period after which soiling is close to its saturation level, and on the other hand, it will permit to correlate these coefficients to the environmental factors, in order to select the most appropriate ones for building dose-response functions for soiling, with broad geographical application.