Combined Gamma-Rays and Carbon-12 Nuclei Irradiation Modulates Brain Chemokine and Cytokine Production and Improves Spatial Learning in Tau P301S, but not 5xFAD Mouse Line.

Earlier we showed the pro-cognitive effect of low doses of combined irradiation (including heavy charged particles) on Wistar rats. In the present work we studied the effect of irradiation (gamma-rays, 0.24 Gy; carbon-12, 0.18 Gy, 400 MeV/nucleon) on the course of neurodegenerative process using Tau P301S and 5xFAD transgenic mice lines, experimental models of Alzheimer's disease. Irradiation led to an increase in pro- and anti-inflammatory cytokines and chemokines (IL-2, IL-6, IL-10, KC) in Tau P301S mice, but not in 5xFAD. At the same time, only the Tau P301S line was found to exhibit radiation-induced improvement in spatial learning.

Expression analysis of genes involved in mitochondrial biogenesis in mice with MPTP-induced model of Parkinson's disease.

The mitochondrion is an extremely important organelle that performs various functions in the cell: e.g. energy production, regulation of respiration processes and maintenance of calcium homeostasis. Disruption of the biogenesis and functioning of this organelle can lead to cell damage and cell death. Mitochondrial dysfunction has been shown to possibly be involved in the pathogenesis of Parkinson's disease. However, the role of genes associated with mitochondrial biogenesis in the early stages of disease remains poorly understood. The objective of the present study was to analyze changes in the expression of activator (Nrf1, Ppargc1a, Prkn, and Kif1b) and repressor (Zfp746 and Mybbp1a) genes of mitochondrial biogenesis in the early stages of the development of neurodegeneration in an MPTP-induced model of presymptomatic and early symptomatic stages of PD. Statistically significant changes in expression at the mRNA level were detected for all studied genes. There was mainly a decrease in the expression of activator genes (Nrf1, Ppargc1a, Prkn, and Kif1b) at all stages of neurodegeneration, which seemed to be associated with impaired mitochondrial biogenesis and the development of neurodegeneration processes. A predominant decrease in the expression was detected for the Zfp746 and Mybbp1a repressor genes of mitochondrial biogenesis. However, in this case, it was associated with the emergence of compensatory mechanisms during the development of Parkinson's disease. The largest number of statistically significant changes was detected for the Nrf1 activator gene and the Mybbp1a repressor gene. Apparently, these two genes play the most important role in this disease.

Surface- and tip-enhanced resonant Raman scattering from CdSe nanocrystals.

Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir-Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 10(3) was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 10(4). This is an important step towards the detection of the phonon spectrum from a single QD.

Geometrically induced modification of surface plasmons in the optical and telecom regimes.

We demonstrate that the introduction of a subwavelength periodic modulation into a metallic structure strongly modifies the guiding characteristics of the surface plasmon modes supported by the system. Moreover, it is also shown how a new type, to our knowledge, of a tightly confined surface plasmon polariton mode can be created by just milling a periodic corrugation into a metallic ridge placed on top of a metal surface.

Domino plasmons for subwavelength terahertz circuitry.

A new approach for the spatial and temporal modulation of electromagnetic fields at terahertz frequencies is presented. The waveguiding elements are based on plasmonic and metamaterial notions and consist of an easy-to-manufacture periodic chain of metallic box-shaped elements protruding out of a metallic surface. It is shown that the dispersion relation of the corresponding electromagnetic modes is rather insensitive to the waveguide width, preserving tight confinement and reasonable absorption loss even when the waveguide transverse dimensions are well in the subwavelength regime. This property enables the simple implementation of key devices, such as tapers and power dividers. Additionally, directional couplers, waveguide bends, and ring resonators are characterized, demonstrating the flexibility of the proposed concept and the prospects for terahertz applications requiring high integration density.

[Partial androgen deficiency in aging male (Padam syndrome): terminology and current approaches to choice of replacement hormonal therapy].

The authors propose a novel approach to treatment of PADAM syndrome based on stimulation of synthesis of endogenic testosterone. A total of 150 patients with PADAM were examined in the Endocrinological Research Center. The examination included physical and andrological examinations with digital rectal investigation of the prostate, filling-in questionnaires, hormonal and biochemical tests. In view of positive test with chorionic gonadotropin (CG), therapy of choice was stimulating therapy with CG. The dose was adjusted individually - from 1000 to 3000 units once in 4 days (1000 units dose was given to 20% patients, 2000 - to 70% and 3000 - to 10% patients). Efficacy did not reduce in long-term treatment. The authors make the following conclusion: choice of PADAM therapy should be individual and based on the age of the patient, body mass index, the necessity to retain spermatogenesis, packed cell volume, associated diseases. Secondary nature of PADAM and positive test for CG allows usage of CG as a perspective therapy in prevention and treatment of age-related lowering of testosterone.

[Results of studies of carbohydrate metabolism and ultrasonography of the pancreas in man after continuous anti-orthostatic hypokinesia]. / Rezul'taty issledovanii sostoianiia uglevodnogo obmena i ul'trazvukovoi kartiny podzheludochnoi zhelezy u cheloveka pri dlitel'noi antiortostaticheskoi gipokinezii.

Data on the hypokinesia-induced transformation of the glycemic profile and ultrasonic changes in the pancreas structure are presented. The AOH study gave further evidence of transforming glycemic curves. Moreover, increased sizes of tail and head of the pancreas and a decrease in its echogeneity were observed in all test-subjects. Structural changes in the pancreas were confirmed by biochemical investigations which revealed increased levels of blood enzymes and activation of insulin secretion. Increases in the liver size, thickness of the wall of the stomach, diameter of the splenic vein were indicative of progressing venous plethora in the portal vein system. It was shown that venous plethora are the main cause for changes in the upper GI, and in the pancreas state in particular, which can be qualified as dysfunctional. These structural changes in the pancreas could suppress its functional activity manifested by increases in blood enzymes and hormones and transformation of the glycemic profile during the glucose load.

[The development of the syndrome of congestive parenchymatous organs under conditions of short-term hypokinesia]. / Razvitie sindroma zastoinykh parenkhimatoznykh organov v usloviiakh kratkovremennoi gipokinezii.

Five series of head-down (-10 degrees to -30 degrees, up to 18 hr) tilt tests were performed with participation of 65 healthy male subjects. The ultrasonic technique was used to investigate the liver, spleen, pancreas, kidney, and the main abdominal vessels, i.e. aorta in the abdomen and superior mesenteric artery, interior caval, portal, and splenic veins. A few hours of HDT already brought about a complex of load-deprivation reflexes (the syndrome of stagnant parenchymal organs) characterized by a prolonged venous congestion in the abdominal organs-vessels system, increases in sizes and blood filling of the liver, spleen, pancreas, kidney, and the main arteries and veins in this hemodynamic region. This was the first time when increases in pancreas including its head, body and tail, and the abdominal blood vessels were quantified at the beginning of adaptation to HDT. The load-deprivation reflexes arising in this period were hemodynamic by nature. Considering the significant functional strain of the abdominal organs and vessels and particularly the limited control of excessive blood flow towards the pancreas and kidneys, there is a good reason to look into the ways to improve the existing countermeasures against the consequences of immobilization for humans both in general clinic and preventive medicine, and in short- and long-term space missions.

Ultrasonic research of abdominal organs in conditions of long-term antiorthostatic hypokinesia.

Change in functional activity of digestive system in space flight usually is associated with phenomenon of hypokinesia which takes place in microgravity. However, it is marked that the reorganization of a gastrointestinal tract in space flight occurs on a background of the phenomenon of venous plethora in abdominal cavity, which can also result in changes of functional activity in organs of digestive system. Insignificant amount of studies of venous plethora in abdominal cavity carried out in conditions of space flight does not allow to create a complete picture of this phenomenon. Hemodynamical changes comparable to microgravity are well-simulated in conditions of a long-term antiorthostatic hypokinesia (AH)--bed-rest in a head-down tilt. The present research was performed with the aim to study venous plethora in abdominal cavity in conditions of long-term AH.

[The inhibiting effect of 8-Cl-adenosine-3',5'-cyclophosphate on the growth of melanoma B-16 in mice]. / Tormoziashchii éffekt 8-VCl-adenozin-3',5'-tsiklofosfata na rost melanomy B-16 u myshei.

A site-selective analogue of the cyclic adenosine monophosphate 8-chloro-adenosine-3',5'-cyclophosphate was studied for its effects on the growth of transplanted murine melanoma B-16. When the agent was given to the mice, a substantial effect on the growth of the tumor was produced by a number of factors, which included the route of administration, concentration of the agent, the time and duration of therapy. Intraperitoneal injections of the agent in a dose of 20 mg/kg/day which were made during three consecutive days, beginning from day 5 after tumor transplantation caused a 58% decrease in tumor growth as compared to the controls. An examination of tumour biopsy specimen revealed that after a course of the injections there was a significant suppression of the activity of cAMP-dependent protein kinase, type I, and a drastic increase in that of cAMP-dependent protein kinase, type II.