The influence of circulation weather types on the exposure of the biosphere to atmospheric electric fields.

We present an analysis of the impact of circulation weather types (CT) on a factor that might influence biological systems and the human condition, the electric state of the atmosphere. We present results on the influence of CT to the magnitude, the direction (positive or negative), the fluctuation magnitude, and the short-term peaks of the atmospheric electric field (potential gradient, PG), using data from a station in Greece. CTs with high vorticity centers over Greece are associated with high positive and negative excursions of the PG, higher PG variability, and rain events. CTs with thinner 850-500 hPa layer are associated with higher daily mean values of fair-weather PG. We also examine the influence of CT on the frequency and amplitude of the naturally occurring extremely low-frequency electric field fluctuations known as Schumann resonances (SR) using data from a station in Hungary. The first and second mode SR frequencies are increased during CTs associated with higher 500 hPa geopotential heights and higher 850-500 hPa layer thickness. This hints to a lower-upper atmosphere coupling. So, CTs not only influence the general temperature and humidity conditions to which the biosphere is exposed, but they also affect its exposure to atmospheric electric fields.

The applicability of the PTTL dose re-analysis method to the Harshaw LiF:Mg,Cu,P material.

The phototransferred thermoluminescence (PTTL) technique is applied to the Harshaw LiF:Mg,Cu,P material. It is demonstrated that using 254-nm UV light, dose levels as low as 0.2 mGy can be re-estimated. The PTTL efficiency was found to be ∼ 6 % in the dose range of 0.2 mGy-1 Gy, and it appears to be dose-independent. This implies that a simple calibration factor could be applied to the PTTL data for the re-estimation of dose levels. It was demonstrated that with a proper choice of the TL readout parameters, and the UV-light irradiation conditions, dose levels that are relevant to personal or environmental dosimetry can be re-estimated.

UV-induced bleaching of deep traps in Harshaw TLD LiF:Mg,Cu,P and LiF:Mg,Ti.

The effects of UV-induced bleaching of deep traps on Harshaw thermoluminescent (TL) LiF:Mg,Cu,P and LiF:Mg,Ti materials were investigated. During a normal heating cycle, LiF:Mg,Cu,P is limited to a maximum temperature of 240 °C. LiF:Mg,Ti can be read to higher temperatures; however, encapsulation in polytetrafluoroethylene limits the maximum readout temperature to 300 °C. Generally, for both materials, these respective temperatures are sufficient for emptying traps corresponding to the main dosemetric peaks. However, when the dosemeters are subjected to a high dose level, such as 1 Gy (much higher than individual monitoring dose levels), higher temperature traps are filled that cannot be emptied without exceeding the above-mentioned maximum temperatures. These high temperature traps tend to be unstable during normal readout and can significantly increase the residual TL signal. The purpose of this study was to investigate the applicability of a UV-induced bleaching technique for emptying higher temperature traps following high-dose applications. In addition, in the case of LiF:Mg,Cu,P, where the maximum readout temperature is significantly lower, we investigated the possibility of reducing the residual signal using the application of repeated readout cycles. The optical bleaching approach was found to be effective in the case of LiF:Mg,Ti; however, for LiF:Mg,Cu,P, no reduction in the residual signal was observed. For this latter material, the application of repeatable readout cycles is very effective and residual signals equivalent to dose levels as low as 0.01 mGy were observed following an initial dose of 5 Gy. To the best of our knowledge, this work is the first attempt to apply an 'optical annealing' technique to the Harshaw thermoluminescent dosemeter (TLD) materials.

HIV bio-behavioural survey among men who have sex with men in Barcelona, Bratislava, Bucharest, Ljubljana, Prague and Verona, 2008-2009.

Data from 23 European countries show that the annual number of HIV diagnoses in men who have sex with men (MSM) increased by 86% between 2000 and 2006. This paper reports the main preliminary results of a bio-behavioural survey in MSM with a specific focus on HIV prevalence and use of United Nations General Assembly Special Session (UNGASS) indicators in six cities in Southern and Eastern Europe. Time-location sampling (TLS) was used. A total number of 2,356 questionnaires and 2,241 oral fluid samples were collected (invalid samples 4.1%). The data show different socio-demographic patterns across countries regarding age, level of education, living conditions, living area and self-identity. Southern European cities had the highest percentage of people who had tested for HIV and collected the result. More than 50% of respondents in the sample from Barcelona reported having used a condom last time they had anal sex (57.2%), whilst in all other cities this proportion was below 50%. The cities with the highest HIV prevalence in MSM were Barcelona (17.0%) and Verona (11.8%) whilst lower percentages were reported in Bratislava (6.1%), Bucharest (4.6%), Ljubljana (5.1%) and Prague (2.6%). The low prevalence in Eastern European cities is encouraging. However, with the level of high-risk sexual behaviour documented and the lower frequency of HIV test seeking behaviour, there is a clear risk of an increase in HIV transmission.

Suppression of antigen-induced arthritis in rabbits by ex vivo gene therapy.

Gene therapy offers a novel approach to treating human joint diseases such as rheumatoid arthritis. In the present study, we have used the retrovirus, MFG-IRAP, to transfer the human IL-1 receptor antagonist protein (IRAP) gene to rabbits' knees and have assessed its impact on inflammatory and chondrodestructive aspects of the acute phase of antigen-induced arthritis in these joints. Surprisingly, intra-articular expression of IRAP was three- to fivefold higher in arthritic knees than in nonarthritic knees, accumulating to levels of over 20 ng/knee in the highest expressing joints. This level of expression produced a marked chondroprotective effect but a milder anti-inflammatory one. Both the increased cartilage matrix catabolism and the inhibition of matrix synthesis that occur in antigen-induced arthritis were abrogated in the presence of the IRAP gene; the latter effect was particularly strong. Of the indices of inflammation that were examined, only leukocyte influx into the joint space was inhibited, and this effect declined with time. Concentrations of rabbit IL-1 were reduced by the IRAP gene, suggesting inhibition of an autocrine induction loop. These data demonstrate that the course of arthritic disease in the rabbit knee can be altered by genetic manipulation, thus encouraging the further development of gene treatments for human joint diseases.

Direct gene delivery to synovium. An evaluation of potential vectors in vitro and in vivo.

OBJECTIVE: To assess the abilities of various vectors to transfer genes to the synovial lining of joints. METHODS: Vectors derived from retrovirus, adenovirus, and herpes simplex virus as well as cationic liposomes and naked plasmid DNA were evaluated. Each construct contained the lac Z marker gene; and one retroviral construct, and one plasmid also contained a gene encoding human interleukin-1 receptor antagonist. Gene expression was under the control of the human cytomegalovirus promoter in all vectors except the retrovirus, where the endogenous 5' long terminal repeat was retained as the promoter. Cultures of rabbit synovial fibroblasts were exposed to these vectors and stained with X-gal to identify lac Z+ cells. Vectors were then injected directly into rabbits' knee joints, and gene transfer and expression were assessed by X-gal staining and polymerase chain reaction (PCR). RESULTS: Adenovirus was a highly effective vector both in vitro and in vivo, with lac Z gene expression persisting for at least 28 days. However, an inflammatory response was noted in vivo. Cells infected in vitro and in vivo with herpes simplex virus also expressed the lac Z gene at high levels, but expression was limited by cytotoxicity. Retroviruses, in contrast, were effective only under in vitro conditions, permitting cell division. Liposomes gave variable in vitro results; when injected into joints in vivo, gene expression was low and was detectable for only a few days, even though a PCR signal persisted for at least 28 days. Unexpectedly, plasmid DNA was captured by the synoviocytes and expressed transiently following intraarticular injection. CONCLUSION: None of the vectors was ideal for in vivo gene delivery to synovium, although adenovirus was clearly the most effective of those tested. Retroviruses, although poor vectors for in vivo gene delivery, are well suited for ex vivo gene transfer to the synovial lining of joints.

Prevalence of arterial hypertension in a collectivity of adolescents.

Arterial hypertension in adolescents was studied in a group of 899 school boys aged 15-18 years from the vocational school No. 48 of the Bucharest Transport Enterprise (ITB) and the secondary school No. 19 ITB. Essential arterial hypertension in the group investigated was found in proportion of 2.7%, a percentage comparable with that of other European countries (1-3%).

Comparative clinical study of the effects of Na isobutyrate and clofibrate on the clotting factors in patients with atherosclerosis.

The effects of Na isobutyrate and clofibrate on human hemostasis were studied in 24 patients with atherosclerosis. Significant changes were recorded only with respect to platelet adhesiveness and blood fibrinogen concentrations. Thus, the index of platelet adhesiveness decreased significantly in 17 out of 19 patients with high initial values, after six weeks of Na isobutyrate therapy (1 g/day), and in 9 out of 17 patients, after clofibrate administration (1.5 g/day) in the same conditions. Blood fibrinogen concentrations were significantly lowered by clofibrate therapy and only slightly influenced by Na isobutyrate.

Pathogenic role of intravascular coagulation in immune diseases.

The tests for the detection of intravascular coagulation and of secondary fibrinolysis performed in 79 patients with systemic lupus erythematosus and 30 patients with other collagenoses were positive in over 63% of the cases. A highly significant correlation was found between the presence of fibrinolytic degradation products (FDP) and the incidence of nephropathy and renal insufficiency, as well as between the presence of fibrin monomers (Godal's ethanol-gelification test) and the evolutive signs of the primary disease (fever, accelerated ESR).

Investigations on the changes of the blood coagulation-fibrinolysis system as a risk factor for coronary heart disease. I. Prevalence of the changes in the blood coagulation-fibrinolysis system in a middle aged male population.

Platelet count and adhesivity, availability of platelet factor 3, fibrinogen concentration and plasma antiplasmin activity were studied in 2,000 men aged 40 to 60 years. The results were estimated in comparison with the data obtained in 100 young apparently healthy subjects. Platelet count was within normal limits in 90% of the cases but with an increased prevalence of upper normal values. Platelet adhesivity to glass, expressed as adhesivity index, varied widely in both directions : a low index was found in 20.23% of the cases ; the high adhesivity index varied with age from 12.27% in subjects aged 40, to 26.5% in aged 56-60. Availability of platelet factor 3 was clearly increased in a large number of middle-aged men. Fibrinogen concentration correlated with age. Antiplasmin activity was significantly higher in the elderly subjects than in the young controls.