Highly efficient broadband polarization retarders and tunable polarization filters made of composite stacks of ordinary wave plates.

By using the formal analogy between the evolution of the state vector in quantum mechanics and the Jones vector in polarization optics, we construct and demonstrate experimentally efficient broadband half-wave polarization retarders and tunable narrowband polarization filters. Both the broadband retarders and the filters are constructed by the same set of stacked standard multiorder optical wave plates (WPs) rotated at different angles with respect to their fast polarization axes: for a certain set of angles this device behaves as a broadband polarization retarder, while for another set of angles it turns into a narrowband polarization filter. We demonstrate that the transmission profile of our filter can be centered around any desired wavelength in a certain vicinity of the design wavelength of the WPs solely by selecting appropriate rotation angles.

Efficient broadband composite optical isolator.

A new design of a broadband optical isolator, composed as a sequence of ordinary Faraday rotators and achromatic quarter-wave plates (QWPs), is presented. In particular, we demonstrate that by using four Faraday rotators and six achromatic QWPs, rotated at specific angles, optical isolation better than 15 dB over the range from 700 to 1000 nm can be achieved. The measured transmittance (corrected for absorption and reflection) in the forward direction over the same wavelength range shows broadening of the transmission spectrum compared with the one of a single Faraday rotator.

[Disputable problems of the pathogenesis of implantation of the placenta into the uterine wall].

The review analyzes publications on the clinical and pathomorphological diagnosis of implantation of the placenta (placenta accreta) (500 references). It characterizes the prevalence of placenta accreta in different countries of the world and a rapid increase in this indicator because of a rise in cesarean sections with further uterine scars. The clinical variants, major pathomorphological types, risk factors of this severe puerperal obstetric complication and the existing hypotheses of its pathogenesis are given. Promises for further studies of the mechanisms for implantation of villi and surrounding components of the uterine placental bed are denoted.

Does single-dose cell resistance to the radio-mimetic zeocin correlate with a zeocin-induced adaptive response in Chlamydomonas reinhardtii strains?

This study aimed to test whether a correlation exists between single-dose resistance to zeocin and the ability to develop a zeocin-induced adaptive response (AR) in Chlamydomonas reinhardtii strains. Three genotypes were used: wild type (WT) strain 137C and two strains (H-3 and AK-9-9), which are highly resistant to radiation based on survival studies. Based on a micro-colony assay, the strains could be arranged according to their single-dose resistance to zeocin as follows: AK-9-9 > H-3 > 137C. However, zeocin induced a similar level of DSB in strains AK-9-9, H-3 and 137C. The radio- and zeocin-resistant strains AK-9-9 and H-3 showed higher DSB rejoining capacity than the WT strain 137C, suggesting that DSB rejoining can at least partly account for different cell survival. Both WT and radio-resistant strains develop zeocin-induced AR involving increased DSB rejoining. The radio- and zeocin-resistant strains AK-9-9 and H-3 again showed higher DSB rejoining capacity than the WT strain 137C. The higher resistance of strains H-3 and AK-9-9 did not abrogate their ability to adapt, albeit with a smaller magnitude as compared to the WT strain. The obtained results characterize new radio-resistant C. reinhardtii strains, which enrich the collection of resistant C. reinhardtii strains.

Autoimmune thyroid disorders in juvenile chronic arthritis and systemic lupus erythematosus.

The appearance of autoimmune thyroiditis in the course of other autoimmune diseases, which do not affect specific organs (systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis and others), is more frequent than is usually believed. Nevertheless, it is scarcely studied, especially in children. The purpose of this study was to look for autoimmune lesions of the thyroid gland in children suffering from juvenile chronic arthritis (JCA) and systemic lupus erythematosus (SLE). Twenty seven children having JCA and twelve children with SLE, aged 5 to 18 years, were enrolled into study. In all of them the disease was in an active phase. The serum levels of total thyroid hormones (T3, T4) and TSH, thyroid antibodies (TAB and MAB) and antinuclear antibodies (ANAB) were analyzed using respectively fluoroimmunologic, microhemagglutination and indirect immunofluorescention tests. According to our results, autoimmune thyroiditis was found in 12 out of 27 children with JCA (44.4%); 85.2% of them were euthyroid, 11.1% had a compensated hypothyroidism, and 3.7% had Hashi-toxicosis. From a clinical point of view, very interesting was the combination of JCA, autoimmune thyroiditis and pseudoxanthoma elasticum in a 13-year old girl. Positive thyroglobulin antibodies (1:80-1:5120) were found in 17 out of 27 cases of JCA (63%). The microsomal antibodies were elevated (1:100-1:1600) in 7 out of 27 (25.9%); antinuclear antibodies (1:80-1:640) were detected in 15 out of 27 cases of JCA (55.5%). A simultaneous elevation of all three kinds of antibodies was found in 14.8% of children with JCA, and of TAB and MAB--in 18.5%. Thyroid gland disorders were detected also in children suffering from SLE. Thyroglobulin antibodies were positive (1:80-1:5120) in 7 out of 12 cases. Antinuclear antibodies (1:320-1:2560) were detected in 8 out of 12 cases (66.7%). The serum levels of T3, T4 and TSH were in the reference limits in all children with SLE. The present study suggests that involvement of the thyroid gland is not uncommon in autoimmune disease in Autoimmune thyroiditis can occur in association with other autoimmune diseases, affecting some organs or systems, such as the insulin-dependent diabetes mellitus, pernicious anaemia, thrombocytopenia, vitiligo, as well as some chromosomal aberrations--Turner's syndrome, Noonan's syndrome and Down's disease [1]. The appearance of autoimmune thyroiditis together with other autoimmune diseases which do not affect specific organs (such as systemic lupus erythematosus, Sjögren syndrome) is the reason to classify them in a common subgroup of the autoimmune polyendocrine syndromes--type IIID [2]. The rheumatic diseases are--more frequently than suspected--associated with autoimmune thyroiditis, but this connection is not well studied. The literature offers very scarce information on the problem, especially for the childhood. The purpose of this study was to look for autoimmune lesions of the thyroid gland in children suffering from juvenile chronic arthritis (JCA) and systemic lupus erythematosus (SLE).

Induction of DNA double-strand breaks by zeocin in Chlamydomonas reinhardtii and the role of increased DNA double-strand breaks rejoining in the formation of an adaptive response.

This study aimed to test the potential of the radiomimetic chemical zeocin to induce DNA double-strand breaks (DSB) and "adaptive response" (AR) in Chlamydomonas reinhardtii strain CW15 as a model system. The AR was measured as cell survival using a micro-colony assay, and by changes in rejoining of DSB DNA. The level of induced DSB was measured by constant field gel electrophoresis based on incorporation of cells into agarose blocks before cell lysis. This avoids the risk of accidental induction of DSB during the manipulation procedures. Our results showed that zeocin could induce DSB in C. reinhardtii strain CW15 in a linear dose-response fashion up to 100 microg ml(-1) which marked the beginning of a plateau. The level of DSB induced by 100 microg ml(-1) zeocin was similar to that induced by 250 Gy of gamma-ray irradiation. It was also found that, similar to gamma rays, zeocin could induce AR measured as DSB in C. reinhardtii CW15 and this AR involved acceleration of the rate of DSB rejoining, too. To our knowledge, this is the first demonstration that zeocin could induce AR in some low eukaryotes such as C. reinhardtii.

Oxygen: modulator of physiological and pathophysiological processes in the liver.

Oxygen has important functions as substrate for biochemical reactions and as modulator of gene expression. In the liver, the physiologically occurring oxygen gradient is a major effector of metabolic zonation. In addition, cross-talks between the O2 signaling and nutrient signaling chains initiate a dynamic zonation pattern. Under pathological situations, hypoxia appears to be a major determinant for liver diseases and cancer. Thereby transcription factors of the HIF family are activated whereas USF proteins have the potential to counteract HIFs. In addition, feedback mechanisms between hypoxia, HIF and the IGF axes appear to exist. Thus, the knowledge of these mechanisms may help to initiate new therapies in diseases with disturbed O2 availability.