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Recent work suggests that Ras small GTPases interact with the anionic lipid phosphatidylserine (PS) in an isoform-specific manner, with direct implications for their biological functions. Studies on PS-Ras associations in cells, however, have relied on immuno-EM imaging of membrane sheets. To study their spatial relationships in intact cells, we have combined the use of Lact-C2-GFP, a biosensor for PS, with multicolor super resolution imaging based on DNA-PAINT. At ~20 nm spatial resolution, the resulting super resolution images clearly show the nonuniform molecular distribution of PS on the cell membrane and its co-enrichment with caveolae, as well as with unidentified membrane structures. Two-color imaging followed by spatial analysis shows that KRas-G12D and HRas-G12V both co-enrich with PS in model U2OS cells, confirming previous observations, yet exhibit clear differences in their association patterns. Whereas HRas-G12V is almost always co-enriched with PS, KRas-G12D is strongly co-enriched with PS in about half of the cells, with the other half exhibiting a more moderate association. In addition, perturbations to the actin cytoskeleton differentially impact PS association with the two Ras isoforms. These results suggest that PS-Ras association is context-dependent and demonstrate the utility of multiplexed super resolution imaging in defining the complex interplay between Ras and the membrane.

This work presents the two space vector pulse width modulation (SVPWM-I and SVPWM-II) strategies for eleven-level (11L) asymmetric cascaded H-bridge (CHB) multilevel inverter (MLI). Depending on the isolated structure and nonappearance of capacitor voltage balancing issues, the CHB MLI structure is favoured. These days, the SVPWM control method is accomplished superior consideration among the diverse PWM methods. In common, the SVPWM strategy is realized based on deteriorating higher-level hexagons into a lower level hexagon (2-level). Compared to the classical SVPWM strategy, the proposed SVPWM-I strategy decreases the memory and mathematical burden necessity included within the demonstration of eleven-level SVPWM devoid of losing the inverter output voltage (AC) contour by diminution the number of two-level hexagons. Also, the SVPWM-II strategy is presented, which incredibly diminishes the mathematical endeavours. The presented two SVPWM methods performed on an eleven-level asymmetric CHB multilevel inverter (MLI) by utilizing SIMULINK/MATLAB program tool and are compared with conventional sinusoidal PWM and Third harmonic injection (THI) PWM methods to confirm the proposed SVPWM methods. The proposed SVPWM methods give higher AC RMS voltage and lower harmonic distortion when compared to SPWM and THIPWM methods. To validate the presented two SVPWM control schemes, hardware results are taken on asymmetric eleven-level CHB MLI.

Composite polymer electrolyte films containing various concentrations of nano-Dy2O3 (1.0 to 4.0%) in PVA + sodium citrate (90 : 10) are synthesized adopting solution cast method and are characterized using FTIR, XRD, SEM, and DSC techniques. The investigations indicate that all components are homogenously dispersed. Films containing 3% of nano-Dy2O3 are more homogenous and less crystalline, and the same is supported by DSC studies indicating the friendly nature to ionic conductivity. Transference number studies reveal that the major charge carriers are ions. With the increase in % of nano-Dy2O3, the conductivity increases and reaches maximum in 3% film with a value of 1.06 × 10−4 S/cm (at 303 K). Further, the conductivity of the film increases with raise in temperature due to the hopping of interchain and intrachain ion movements and fall in microscopic viscosity at the matrix interface of the film. Electrochemical cells are fabricated using these films with the configuration “anode (Mg + MgSO4)/[PVA (90%) + Na3C6H5O7 (10%) + (1–4% nano-Dy2O3)]/cathode (I2 + C + electrolyte),” and various discharge characteristics are evaluated. With 3% nano-Dy2O3 film, the maximum discharge time of 118 hrs with open-circuit voltage of 2.68 V, power density of 0.91 W/kg, and energy density of 107.5 Wh/kg are observed. These findings reflect the successful adoption of the developed polymer electrolyte films in electrochemical cells.

Varying concentrations of nano-Pr2O3 doped in “PVA + Sodium Citrate (90 : 10)” polyelectrolyte films are synthesized using solution cast technique and the films are characterized adopting FTIR, XRD, SEM, and DSC methods. The film with 3.0% of nano-Pr2O3 content is more homogenous and possesses more amorphous region that facilitate the deeper penetration of nanoparticles into the film causing more interactions between the functional groups of the polymeric film and nano-Pr2O3 particles and thereby turning the film more friendlily to the proton conductivity. The conductivity is maximum of 7 × 10−4 S/cm at room temperature for 3.0% nano-Pr2O3 film and at that composition, the activation energy and crystallinity are low. With increase in temperature, the conductivity is increasing and it is attributed to the hopping of interchain and intrachain ion movements and furthermore decrease in microscopic viscosity of the films. The major charge carriers are ions and not electrons. These films are incorporated successfully as polyelectrolytes in electrochemical cells which are evaluated for their discharge characteristics. It is found that the discharge time is maximum of 140 hrs with open circuit voltage of 1.78 V for film containing 3% of nano-Pr2O3 and this reflects its adoptability in the solid-state battery applications.

Abstract Extracellular vesicles (EVs) have been shown as key mediators of extracellular small RNA transport. However, carriers of cell-free messenger RNA (cf-mRNA) in human biofluids and their association with cancer remain poorly understood. Here, we performed a transcriptomic analysis of size-fractionated plasma from lung cancer, liver cancer, multiple myeloma, and healthy donors. Morphology and size distribution analysis showed the successful separation of large and medium particles from other soluble plasma protein fractions. We developed a strategy to purify and sequence ultra-low amounts of cf-mRNA from particle and protein enriched subpopulations with the implementation of RNA spike-ins to control for technical variability and to normalize for intrinsic drastic differences in cf-mRNA amount carried in each plasma fraction. We found that the majority of cf-mRNA was enriched and protected in EVs with remarkable stability in RNase-rich environments. We observed specific enrichment patterns of cancer-associated cf-mRNA in each particle and protein enriched subpopulation. The EV-enriched differentiating genes were associated with specific biological pathways, such as immune systems, liver function, and toxic substance regulation in lung cancer, liver cancer, and multiple myeloma, respectively. Our results suggest that dissecting the complexity of EV subpopulations illuminates their biological significance and offers a promising liquid biopsy approach.

Abstract The discovery and utility of clinically relevant circulating biomarkers depend on standardized methods that minimize preanalytical errors. Despite growing interest in studying extracellular vesicles (EVs) and cell-free messenger RNA (cf-mRNA) as potential biomarkers, how blood processing and freeze/thaw impacts the profiles of these analytes in plasma was not thoroughly understood. We utilized flow cytometric analysis to examine the effect of differential centrifugation and a freeze/thaw cycle on EV profiles. Utilizing flow cytometry postacquisition analysis software (FCMpass) to calibrate light scattering and fluorescence, we revealed how differential centrifugation and post-freeze/thaw processing removes and retains EV subpopulations. Additionally, cf-mRNA levels measured by RT-qPCR profiles from a panel of housekeeping, platelet, and tissue-specific genes were preferentially affected by differential centrifugation and post-freeze/thaw processing. Critically, freezing plasma containing residual platelets yielded irreversible ex vivo generation of EV subpopulations and cf-mRNA transcripts, which were not removable by additional processing after freeze/thaw. Our findings suggest the importance of minimizing confounding variation attributed to plasma processing and platelet contamination.

Background: Residency programs have developed monetary initiatives for students underrepresented in medicine (URiM). Our team sought to provide a centralized resource for URiM students seeking plastic surgery subinternships with funded opportunities., Methods: A cross sectional analysis of URiM scholarships offered by US integrated plastic surgery programs (n = 91) between July and September 2023. The study used residency program web domains. Investigators collected information on the monetary value of scholarship, eligibility criteria, and required application documents. Inferential analyses were conducted to investigate whether programs' geographic region or Doximity ranking played a role in likelihood of scholarship existence., Results: The study found that approximately 52.7% (n = 48) of programs have in place monetary support for underrepresented visiting medical students (eg, stipend or reimbursement). The average monetary support was $1670. A univariate test demonstrated that programs with lower rankings in both reputation and research were less likely to have a scholarship available than higher ranking programs ( P = 0.002; P = 0.02, respectively). Programs located in the Midwest regions were 3.5 times more likely to have a diversity scholarship available ( P = 0.034). In our multivariate analysis, reputation ranking and geographic region remained significant. A Pearson chi square test showed the greatest proportions of scholarships among geographically similar programs to be in the Midwest (70%), however, not statistically significant., Conclusions: This study provides a centralized resource for URiM students interested in completing away rotations. Further investigation into development of these scholarship opportunities would be of much benefit and could guide other programs in the funding their own diversity scholarships., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Intervertebral disk (IVD) degeneration is a multifactor process that results in the physical destruction of the nucleus pulposus (NP) and annulus fibrosus (AF). This compromises IVD function and causes significant disability and economic burden. Strategies to replace the entire composite structure of the IVD are limited and most approaches do not recapitulate the heterogenous biochemical composition, microarchitecture or mechanical properties of the native tissue. Our central hypothesis was that donor IVDs which resemble the size and biochemistry of human lumbar IVDs could be successfully decellularized while retaining the tissue's structure and function with the long-term goal of creating a composite scaffold for tissue engineering the human IVD. Accordingly, we optimized a procedure to decellularize bovine tail IVDs using a combination of detergents, ultrasonication, freeze-thaw cycles, and nucleases. The resultant decellularized whole IVD xenografts retained distinct AF and NP regions which contained no visible intact cell nuclei and minimal residual bovine deoxyribose nucleic acid (DNA; 65.98 ± 4.07 and 47.12 ± 13.22 ng/mg, respectively). Moreover, the NP region of decellularized IVDs contained 313.40 ± 50.67 µg/mg glycosaminoglycan. The presence of collagen type II was confirmed via immunohistochemistry. Additionally, histological analysis of the AF region of decellularized IVDs demonstrated retention of the native angle-ply collagen microarchitecture. Unconfined compression testing demonstrated no significant differences in swelling pressure and toe-region modulus between fresh and decellularized IVDs. However, linear region moduli, peak stress and equilibrium moduli were all significantly reduced. Together, this research demonstrates a successful initial step in developing a biomimetic acellular whole IVD xenograft scaffold for use in IVD tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2412-2423, 2018., (© 2018 Wiley Periodicals, Inc.)

Smoking increases the risk of forming, growing, and rupture of intracranial aneurysms. We retrospectively reviewed patients with intracranial aneurysms treated by neurosurgical or endovascular treatment--154 patients (45 men, 109 women, 15 to 62 years, average 46.3 years, CI +/- 1.72). We found 74% (114/154) of smokers--80% (36/45) men and 71.6% (78/109) women, with the mean value of the Fagerström Test of Nicotine Dependence 4.4 (CI +/- 0.40). The average age of smoking initiation was 18.2 years (CI +/- 0.66), the average period of smoking 26.8 years (CI +/- 2.13). The average number of cigarettes consumed daily was 18.2 (CI +/- 1.58). With statistical significance p < 0.05, the athero-index was lower in nonsmokers than smokers: 3.4 (CI +/- 0.56) vs. 4.5 (CI +/- 0.51). HDL cholesterol was higher in non-smokers than smokers: 1.6 mmol/L (CI +/- 0.25) vs. 1.4 (CI +/- 0.10), and triglycerides were higher in smokers than non-smokers: 1.3 mmol/l (CI +/- 0.16) vs. 1.9 (CI +/- 0.35). Forty-two per cent of smokers (48/114) were controlled one year after the treatment; 18.8% of them stopped smoking, 41.7% reduced smoking, and 39.6% continued to smoke as extensively as before. The prevalence of smoking in our sample was higher than in the Czech population (28.2%). Only 18.8% of controlled smokers were able to quit one year after the intervention.

The subject of the study was the ecological and human health consequences of environmental pollution from emissions arising from burning local coal with an arsenic content ranging from 900 to 1,500 g/tonne of dry substance. The first indication of environmental pollution by arsenic-containing emissions was the mass extinction of honeybee colonies. The neurotoxic and carcinogenic aspects of arsenic exposure were followed. On using a group diagnostics approach, significant hearing losses were detected in exposed children in both air and bone conduction audiometry at high frequency range (4,000 and 8,000 Hz, respectively). Exposure assessment of the local population of the Prievidza district, Central Slovakia, was based on biological monitoring. The criterion of higher exposure was arsenic content in hair exceeding concentrations of 3 microg/g of hair. In a 7.5-km radius of the exposed region, live about two-tenths of the district population who were considered as "exposed" and rest of the district served as the "reference" population. The subject of our analysis was a database of 1,503 non-melanoma skin cancer (NMSC) cases (756 in men and 747 in women) collected from 1977 to 1996 in the Prievidza district, Central Slovakia (population approximately 125,000). The age standardized incidence of NMSC (each confirmed by histological examination) in non-occupational settings ranged from 45.9 to 93.9 in men and from 34.6 to 81.4 in women. Analysis of our data demonstrates a positive correlation between human cumulative exposure to arsenic and incidence of NMSC.

This paper describes results of two ecological studies design to analyze the incidence of selected malignancies in two populations exposed to polychlorinated hydrocarbons, mostly PCBs and TCDDs/Fs by comparing data available in the National Cancer Registry of the Slovak Republic and National Oncological Registry of the Czech Republic databases for the Slovak Republic (approximately 5M inhabitants) and the Czech Republic (10,3 M inhabitants) to the data relevant for the population of Michalovce District, the Slovak Republic (approximately 112,000 inhabitants) and Uherske Hradiste, the Czech Republic (146,000 inhabitants). Those districts are recognized as PCB-contaminated areas due to production and industrial use of PCBs. Data were analyzed for the 10-year period 1987-1996. The age adjusted world standard ratio (WSR) incidence of thyroid, pancreatic, breast, ovarian, bladder, and brain tumors in females and thyroid, pancreatic, breast, bladder, brain, prostate and testicular tumors in males were compared. Neither PCBs nor TCDDs/Fs appear to contribute to the observed significantly lower incidence of breast and prostate cancer in the Michalovce District and lower bladder cancer incidence in Uherske Hradiste District. However, anti-estrogenic and anti-androgenic properties have been described for hydroxylated and methylsulfonyl PCB metabolites. These properties could contribute to a mechanism through which these metabolites might modulate the development of breast, prostate and bladder cancer. The results of our analysis points to substantial potential problems of risk assessment for cancer incidence in populations exposed to xenobiotics, or more generally, as it relates to a wide spectrum of confoundings of cancer risk factors.

Objective: To describe feeding patterns during first two years of life and their relation to sociodemographic factors., Design: Longitudinal study., Setting: Prague, Czech Republic., Subjects: Ninety-seven full-term healthy singletons enrolled at maternity ward, of which 90.7% completed the study., Methods: Diet was assessed at 9, 12 and 24 months of age using a structured 3-day dietary record. Additional information was obtained from questionnaires completed at birth and at 6 months., Results: The median duration of exclusive breastfeeding was 5 months, and that of total breastfeeding 9 months. Breastfeeding rate 47.4% at 9 months declined to 4.5% at 24 months. Total duration of breastfeeding was positively associated with maternal education and marital status but not with maternal age, gender or birth order. Breastfeeding frequency at 9, 12 and 24 months was 4.8, 4 and 3.7, respectively. The complementary food feeding frequency increased significantly with age (4.5, 4.7 and 5.9 times per day, respectively). All children at any age point consumed fruits, cereal and milk products. The proportion of children consuming meat and vegetables had increased with age but between ages 9 and 24 months, at least 23-38% children did not consume vegetables daily and 28-40% did not consume foods from meat/fish/poultry/eggs group daily. The proportion of children consuming milk and foods associated with the early complementary feeding period had fallen with age while the consumption of cereal foods other than porridge had increased. Values of indicators of adequate complementary feeding practices tentatively suggested in the context of WHO expert consultation had closely reflected breastfeeding rates., Conclusions: Breastfeeding duration is shorter than WHO recommends. It is influenced by maternal education and marital status. Compliance with complementary feeding recommendations is relatively good. Continued promotion of healthy infant and young child feeding practices is needed. Indicators evaluating complementary feeding practices should assess breastfeeding separately from other aspects., Sponsorship: Ministry of Health, 1st Faculty of Medicine, Charles' University of Prague.

Information about smoking impact on pregnancy as well as clear advice to stop and a treatment offer should be included into the health care of pregnant women. We contacted them within the first 3 days after delivery. In the sample of 265 women 23.8% (63/265) smoked during their pregnancy (51.9% with basic education only, 25.8% with high school and 5.0% with university education), and 7% of the sample (19/265) did not quit by the delivery. Only 68% of smokers (43/63) were asked about their smoking habits during the pregnancy by their gynaecologist, and both smokers and non-smokers had insufficient information about the impact of smoking on their baby (40% of smokers and 32% of non-smokers had no idea at all), the doctor was the source of this kind of information only in 5% (13/265) cases. Smokers' children had a lower average birth weight (3.084 g in smokers vs. 3.325 g in non-smokers, p=0.02) and were smaller (49.3 cm vs. 50.5 cm respectively, p=0.02). Smokers' bodyweight increased more than non-smokers' during their pregnancy (gaining 14.8 kg vs. 12.9 kg respectively, p=0.02), they also underwent the delivery at a lower age (27.6 vs. 30.0 years respectively, p<0.01) and after a non-significantly shorter duration of pregnancy (38.7 weeks vs. 39.0 weeks respectively, p=0.53). If 23.8% of pregnant women smoke and 90.6% of them would like to stop, it is a missed opportunity for education and treatment of tobacco dependence by their physicians.

Background: Evaluation of the effect of intervention on changes in the lifestyle of patients with combined familial hyperlipidaemia (CFH)., Methods and Results: The group comprised 154 patients with CFH where changes in the lipid profile, diet, basic anthropometric data and smoking were recorded 3-6 months following intervention. In addition to little willingness to have a check-up examination the authors recorded significant shortcomings in the lifestyle of these patients with a high cardiovascular risk: a large number of smokers (51%), serious shortcomings in the composition of the diet (excessive intake of animal fats a proteins, inadequate intake of vegetable proteins, dietary fibre and vitamins, in particular E and C), overweight and a high percentage of body fat., Conclusions: While the attention devote to pharmacotherapy with hypolipidaemic agents is justified we should not forget systematic intervention as regards changes in lifestyle. This appeal is even more urgent in conjunction with the low motivation and willingness of patients to change their lifestyle. Special attention should be focused on smokers (in addition to effect on lipids also greater cumulation of risk factors).

This study analysed the diet (based on a 7-day-record), smoking habits and basic anthropometric parameters of patients with familial combined hyperlipidaemia (N = 154, 52% men, 48% women, mean age 55.73 +/- 12.95). These data were correlated with blood lipids and lipoproteins. In high-risk patients' diets we found not quantitative, but mostly qualitative shortcomings: the average energy intake was 104% of the recommended daily intake (RDI), but 34% of the energy was derived from fats. The daily fat intake represented 137% of RDI, and 60 g were of animal and 24 g of vegetable origine. The protein intake was 120% of RDI (155% animal, 75% vegetable protein), the carbohydrate intake was only 86% and the fibre intake 71% of RDI. A very high intake both of cholesterol--139% of RDI and NaCl 151% of RDI--was recorded, while the intake of antioxidant vitamins C and E was only 82% and 35% of RDI, respectively. Current smoking was recorded in 51% of patients. Smokers had also a poorer diet: higher animal fat and protein, as well as a higher cholesterol intake, lower vegetable fat, protein, fibre and vitamin E intake. Surprisingly smokers were found to ingest more vitamin C than non-smokers. As to blood lipids: smokers vs. non-smokers had the following values in mmol/l (SD): total cholesterol 7.8 (+/- 1.3) vs. 7.7 (+/- 1.82), triacylglycerols 3.27 (+/- 2.13) vs. 3.2 (+/- 3.11), HDL-cholesterol 1.25 (+/- 0.39) vs. 1.36 (+/- 0.43), LDL-cholesterol 5.11 (+/- 1.39) vs. 4.95 (+/- 1.51), and, in g/l, apolipoprotein A1 1.8 (+/- 0.30) vs. 1.66 (+/- 0.35), apolipoprotein B 1.66 (+/- 0.35) vs. 1.52 (+/- 0.44), lipoprotein (a) 0.36 (+/- 0.27) vs. 0.43 (+/- 0.50), all without statistical significance. For smokers vs. non-smokers anthropometric data were as follows (mean, SD): body mass index (BMI) 27.74 (+/- 3.77) vs. 27.02 (+/- 3.30), waist/hip ratio (WHR) 0.895 (+/- 0.086) vs. 0.911 (+/- 0.093), and % of body fat 29.6 (+/- 7.4) vs. 27.9 (+/- 7.9). Our conclusions suggest, that lifestyle choice are of great importance for patients with this serious genetic lipid metabolism disorder and that it is important to recognise the danger of risk factor cumulation in connection with cardiovascular diseases.

Background: Evaluation of the negative impact of active smoking on lipid and lipoprotein serum levels and the relationship with body mass index (BMI) and waist/hip ratio (WHR)., Methods and Results: The group was formed by 178 (77 men and 101 women), mean age 54 years (SD 6.2 attending the lipid out-patient department at the Third Medical Clinic, First Medical Faculty, Charles University Prague. Attention was paid to whether the patients were treated with hypolipidaemic agents or not. A statistically significant difference (p < 0.05) was found between smokers and non-smokers as regards total cholesterol (mean values and SD) in the group of 80 treated women (smokers 7.84 mmol/l, SD 1.21). Significantly higher values of LDL cholesterol in smokers as compared with non-smokers (6.00 mmol/l SD 2.08 vs. 4.8 mmol/l, SD 1.26) were recorded in the group of treated women. Other results were also to the disadvantage of smokers (with the exception of non-treated women), though the difference was not statistically significant: non-treated female smokers had a higher LDL cholesterol (4.24 mmol/l, SD 1.42) as compared with non-treated non-smokers (5.3 mmol/1, SD 0.60). In treated men the LDL cholesterol value in smokers (5.20 mmol/l SD 1.20) were also higher than in non-smokers (4.54, SD, 1.15). Triacylglycerols in women (smokers vs. non-smokers): in the group of treated women 3.11 mmol/l, SD 4.86 vs 1.94 mmol/l SD 1.08, in the group of non-treated women 3.74 mmol/l, SD 4.77 vs. 1.94 mmol/l, SD 0.74. Triacyglycerols in men (smokers vs. non-smokers): in the treated men 3.87 mmol/l SD 3.54 vs. 2.62 mmol/l, SD 1.63, in the non-treated men 10.62 mmol/l, SD 9.86 vs. 2.86 mmol/l, SD 1.63. HDL-cholesterol in women (smokers vs. non-smokers): in the treated group 1.24 mmol/l SD 0.46 vs. 1.39 mmol/l, SD 0.35, in the group of non-treated men 1.54 mmol/l, SD 0.37, vs. 2.86 mmol/l, SD 1.64. HDL cholesterol in men (smokers vs. non-smokers): in the treated group 1.15 mmol/l, SD 0.30 vs. 1.27 mmol/l, SD 0.31, in the non-treated group 1.09 mmol/l, SD 0.40 vs. 1.15 mmol, SD 0.28. In female smokers treated and non treated and in non-treated male smokers the WHR values were higher, in treated smokers lower despite the surprisingly higher BMI., Conclusion: Active smoking has an adverse impact on serum lipid and lipoprotein levels in patients with familial combined hyperlipidaemia.

Evidence was provided that in a repeatedly irradiated bacterial suspension of Escherichia coli K12: AB 1157, 1886, 2463, under the described experimental conditions, gradually mutants more resistant to UV radiation survive. Under these circumstances it may happen that selection and an increase of bacterial clones with an increased UV resistance develop, manifested by a reduced effectiveness of UV radiation during repeated irradiation. Although the cumulating damage of DNA in microbes can lead to a reduction of their survival as well as a reduction of their absolute numbers, it can be hardly assumed that during practical use in air conditioning units or during disinfection of drinking water all bacteria will be destroyed. In that case even repeated UV irradiation is not necessarily a reliable disinfection tool.

At the 1st Medical Faculty of Charles University in Prague the prevalence of smoking was investigated among the faculty, staff, students and among health professionals in the country. We found 38.1% smokers (current and occasional) among malephysicians (N = 625), 25.6% smokers among women physicians (N = 394), 48.7% smoking nurses (N = 729) and 42.3% smokers among paramedical staff (N = 298). We have also followed up smoking habits among our students since 1989 (N = 1235). The number of smokers among them rose from 7% in 1989 to 18% in 1994. Students were also asked about their opinion on smoking as a risk factor for coronary heart disease which has a rising trend. Trying to coordinate the anti-smoking activity at all seven medical faculties in the Czech Republic, in collaboration with the Faculty of Medicine of Masaryk University in Brno, the National Centre for Health Promotion and the Czech Commission of EMASH, present the main points of the anti-smoking strategy at Czech medical faculties.

For three years some characteristics of life-style of medical students in the fifth year of The 1st Medical Faculty, Charles University, Prague, were followed with a view to risk factors of ischemic heart disease (ICHS). At the same time opinion of these students on the validity of these factors were established. Altogether it deals with 623 students of which they are 269 men and 354 women of average age 23.1 years in whom 12 risk factors were followed. The results show that medical students do not lead an exemplary life-style. For example, during the following three years there was actually a significant increase in number of smokers (from 7% to 22%) and corresponding to this the significance assigned to this risk factor has decreased.

In conjunction with contamination of the atmosphere by freons interest in geophysical and health aspects of "ozone holes"--seasonal incidence of increased intensity of UV radiation--is increasing. Its biological effects depend on the intensity, period of exposure and wavelength. There is a wide range of different damage, local as well as general. In addition to pigmentation of the skin and symptoms produced by an elevated histamine blood level we find also changes which may have more serious and permanent consequences. These changes include the number and structure of Langerhans islets, changes of the peripheral capillary walls, dimerization of pyrimidine and thymine in DNA. These changes contribute to the development of malignancies of the skin. After exposure of the eye changes of pigmentation are found, and depending on the dose, also development of conjunctivitis or retinal damage. Recently interaction of UV radiation with arsenic was investigated. Conversely therapeutic effects of UV radiation in combination with chemotherapy are used in dermatology, such as inhibition of contact sensitization.