42 research outputs found
Aluminum
Glin (Al) jest srebrzystobia艂ym metalem o masie atomowej 26,98 i temperaturze topnienia 660,4 C. Zawarto艣膰 glinu w skorupie ziemskiej wynosi oko艂o 8%. Produkcja glinu polega na elektrolizie tritlenku glinu (Al2O3) zmieszanego z topnikami. Aluminium znajduje zastosowanie do wyrobu naczy艅 powszechnego u偶ytku i aparatury chemicznej. Jest wykorzystywany przy produkcji samochod贸w, samolot贸w, w metalurgii, do pokrywania zwierciade艂 teleskop贸w, papier贸w dekoracyjnych i opakowa艅. Sproszkowany metal stosuje si臋 w laboratoriach jako czynnik redukuj膮cy, przy produkcji materia艂贸w wybuchowych, pigment贸w, proszk贸w b艂yskowych i farb oraz przy spawaniu cz臋艣ci stalowych metod膮 Goldschmidta. Nara偶enie zawodowe w przemy艣le wi膮偶e si臋 z produkcj膮 glinu, technologiami spawania oraz produkcj膮 finalnych wyrob贸w z glinu. Nie ma danych dotycz膮cych toksyczno艣ci ostrej u ludzi. Natomiast przewlek艂e nara偶enie zawodowe ludzi na py艂y glinu prowadzi do wyst膮pienia w p艂ucach zmian o charakterze pylicy p艂uc. Obserwowano tak偶e nast臋puj膮ce zmiany: zw艂贸knienia w p艂ucach, zapalenie p臋cherzyk贸w p艂ucnych, proteinoz臋 p臋cherzyk贸w p艂ucnych, zapalenia oskrzeli i przewlek艂e 艣r贸dmi膮偶szowe zapalenie p艂uc. W kilku badaniach populacji pracownik贸w nara偶onych zawodowo na py艂y glinu wykazano wzrost liczby przypadk贸w wyst臋powania zmian zw艂贸knieniowych w p艂ucach, zale偶nie od st臋偶enia frakcji respirabilnej py艂贸w w powietrzu. Dzia艂anie zw艂贸kniaj膮ce py艂贸w glinu wykazano r贸wnie偶 w kilku eksperymentach przeprowadzonych na zwierz臋tach do艣wiadczalnych. W kilku pracach podj臋to pr贸b臋 oceny zaburze艅 ze strony uk艂adu nerwowego u pracownik贸w nara偶onych na dymy i py艂y glinu. Nie ma jednak wystarczaj膮cych dowod贸w takiego dzia艂ania, gdy偶 w 偶adnym z tych bada艅 nie stwierdzono objaw贸w ogniskowych organicznego uszkodzenia o艣rodkowego i obwodowego uk艂adu nerwowego. Glin nie wykazuje dzia艂ania mutagennego, genotoksycznego ani rakotw贸rczego. Nie dzia艂a r贸wnie偶 embriotoksycznie i teratogennie. Ze wzgl臋du na fakt, 偶e nara偶enie zawodowe na py艂y glinu jest nara偶eniem z艂o偶onym, w kt贸rym wyst臋puj膮 r贸wnie偶 inne zwi膮zki pylicotw贸rcze, wydaje si臋, 偶e wyliczona warto艣膰 normatywu higienicznego powinna obejmowa膰 st臋偶enie glinu zar贸wno frakcji respirabilnej py艂u jak i py艂u ca艂kowitego. Za podstaw臋 wyliczenia warto艣ci NDS przyj臋to badania, w kt贸rych wykazano, 偶e u badanych 53 pracownik贸w nara偶onych na py艂y glinu o st臋偶eniu 1,4梅10 mg/m3 frakcji respirabilnej wykryto 1 przypadek zw艂贸knienia p艂uc i 3 przypadki z niewielkimi zmianami w p艂ucach, wskazuj膮cymi na pocz膮tki proces贸w zw艂贸knieniowych. Wzrost st臋偶e艅 frakcji respirabilnej powy偶ej 10 mg/m3 (10梅100 mg/m3) przyczynia艂 si臋 do wzrostu liczby obserwowanych przypadk贸w zw艂贸knie艅 w p艂ucach. St臋偶enie 10 mg/m3 (frakcja respirabilna) przyj臋to jako warto艣膰 LOAEL. Do wyliczenia warto艣ci NDS przyj臋to cztery wsp贸艂czynniki niepewno艣ci. Uzyskano warto艣膰 NDS na poziomie 2,5 mg/m3, kt贸r膮 przyj臋to dla glinu zawartego w pyle ca艂kowitym. Natomiast warto艣膰 NDS py艂u respirabilnego stanowi 艣rednio 50% obliczonej warto艣ci dla py艂u ca艂kowitego, czyli oko艂o 1,2 mg/m3 (jako dymy, py艂 respirabilny). Ustalone warto艣ci NDS powinny zabezpieczy膰 pracownik贸w przed dzia艂aniem zw艂贸kniaj膮cym py艂贸w i dym贸w glinu powstaj膮cych w r贸偶nych procesach wytwarzania i przetwarzania aluminium, a tak偶e przed dzia艂aniem zw艂贸kniaj膮cym innych zwi膮zk贸w pylicotw贸rczych towarzysz膮cych tym procesom. Nie ma podstaw do ustalenia warto艣ci DSB. Ze wzgl臋du na fakt, 偶e dzia艂anie dra偶ni膮ce dym贸w i py艂贸w wyst臋puje jedynie w warunkach nara偶enia d艂ugotrwa艂ego, nie ma podstaw do ustalenia warto艣ci NDSCh.Aluminum (Al) is a silver-white metal with the atomic weight of 26.98 and melting temperature of 660.4 C. The earth鈥檚 crust contains about 8% aluminum. Aluminum production consists in electrolysis of aluminum oxide (Al2 O3). Aluminum is used to produce household equipment and various utensils, as well as chemical appliances, aircraft, motor vehicles, in metallurgy, to cover the surface of telescope mirrors, in decorative wrapping paper and packaging. Powdered metal is used in laboratories as a reduction factor in the manufacturing explosive materials, paints, pigments and in welding with Goldschmidt鈥檚 method. Occupational exposure occurs during aluminum production, in welding technologies, as well as in manufacturing final aluminum products
The Role of Zinc in Selected Female Reproductive System Disorders
Zinc is an essential microelement that plays many important functions in the body. It is crucial for the regulation of cell growth, hormone release, immunological response and reproduction. This review focuses on its importance in the reproductive system of women of reproductive and postmenopausal ages, not including its well described role in pregnancy. Only recently, attention has been drawn to the potential role of zinc in polycystic ovary syndrome (PCOS), dysmenorrhea, or endometriosis. This review is mainly based on 36 randomized, controlled studies on reproductive, pre- and post-menopausal populations of women and on research trying to explain the potential impact of zinc and its supplementation in the etiology of selected female reproductive system disorders. In women with PCOS, zinc supplementation has a positive effect on many parameters, especially those related to insulin resistance and lipid balance. In primary dysmenorrhea, zinc supplementation before and during each menstrual cycle seems to be an important factor reducing the intensity of menstrual pain. On the other hand, little is known of the role of zinc in endometriosis and in postmenopausal women. Therefore, further studies explaining the potential impact of zinc and its supplementation on female reproductive system would be highly advisable and valuable
An Assessment of Metallothionein鈥揅admium Binding in Rat Uterus after Subchronic Exposure Using a Long鈥揟erm Observation Model
Cadmium (Cd) is an environmental pollutant known to pose a public health issue. The mechanism of Cd toxicity on the uterus, including the protective role of metallothionein (MT), is still not fully understood. The aim of the study was to evaluate the degree of MT-Cd binding in the uterus of rats exposed per os to Cd at daily doses of 0.09, 0.9, 1.8 and 4.5 mg Cd/kg b.w. for 90 days. To assess the permanence of the bond, the rats were observed over long observation periods: 90 and 180 days after termination of exposure. Additionally, uterine concentration of Zn, Cu, Ca, Mg was determined. Cd leads immediately after exposure to a max. 30-fold increase in the concentration of Cd in the uterus, with only small amounts being bound to MT. After 90 days following termination of exposure, and especially after 180 days, an increase in MT-Cd concentration was noted for the three highest doses; even so, the degree of Cd binding by MT was still small. Additionally, the accumulation of Cd in the uterus disturbs the homeostasis of determined essential elements, manifested by a significant increase in Cu concentration and a decrease in Zn, Mg and Ca, especially 180 days after termination of exposure. The obtained results indicate that MT has only a slight protective role in the uterus and that Cd ions may have harmful effects not related to MT: directly on the uterine tissue, and indirectly by disturbing the homeostasis of its essential elements
Subchronic Exposure to Cadmium Causes Persistent Changes in the Reproductive System in Female Wistar Rats
The Effect of Zinc and Selenium Supplementation Mode on Their Bioavailability in the Rat Prostate. Should Administration Be Joint or Separate?
It is thought that zinc and selenium de铿乧iency may play a signi铿乧ant role in the etiology of prostate cancer. Although joint zinc and selenium supplementation is frequently applied in the prevention of prostate diseases, the bioavailability of these elements in the prostate after co-administration is still unknown. The study examines the effect of subchronic supplementation of zinc gluconate and selenium compounds (sodium selenite or selenomethionine), administered together or separately, on their bioavailability in the prostate, as well as the induction of metallothionein-like proteins (MTs) bound to zinc in the prostate and liver. Zinc concentration in the dorso-lateral lobe of the prostate was signi铿乧antly elevated already after the 铿乺st month of supplementation of zinc alone. In the supplementation period, the MTs level increased together with zinc concentration. In contrast, the ventral lobe of the prostate did not demonstrate signi铿乧antly higher levels of zinc until after three months of supplementation, despite the MTs induction noted after one-month supplementation. Increased selenium levels in the dorsolateral lobe were observed throughout the administration and post-administration periods, regardless of the selenium compound used or whether zinc was co-administered. The results of our studies suggested for the 铿乺st time that these elements should not be administered jointly in supplementation
The effect of cadmium on the coagulation and fibrinolytic system in women with uterine endometrial cancer and myoma
Objectives: Cadmium (Cd) is a persistent and widespread environmental pollutant, which may constitute a potential risk factor for hormone-dependent tumors such as endometrial cancer. The vascular endothelium is an important target of cadmium toxicity, which may interfere with the coagulation cascade and fibrinolytic system. The aim of this research was to investigate whether in female patients with uterine endometrial cancer or myoma in comparison to healthy women, the concentration of cadmium in blood affects the process of coagulation and fibrinolysis. Materials and Methods: The study group comprised 91 women: 35 healthy (A-control), 39 with uterine myoma (B) and 17 with endometrial cancer (C), in which blood cadmium concentrations (BCd), coagulation and selected fibrinolysis parameters in plasma were assayed. Results: In the women with myoma and especially in those with endometrial cancer disturbances in coagulation and fibrinolysis were detected when compared to the healthy women. In the group of women with endometrial cancer significant changes in prothrombin index, levels of fibrinogen, fibrin D-dimer and t-PA were observed. Whereas, in the patients with myoma significant changes in prothrombin time, index of vWillebrand Factor and fibrin D-dimer level were noted. Mean BCd concentrations in subsequent groups were as follows: B - 0.91卤0.81; C - 0.78卤0.45 渭g Cd/l and did not differ significantly in comparison with the control group (0.86卤0.35 渭g Cd/l). However, in each study group smokers had approximately twice as high BCd as non-smokers. Studies also showed significant associations between BCd and fibrinogen level and thrombin time among the women with myoma and endometrial cancer, as well as in healthy women. Moreover, thrombin time significantly correlated with fibrinogen level in the women studied. Conclusions: In the patients with myoma and especially in these with endometrial cancer disturbances in coagulation and fibrinolysis parameters leading to hypercoagulability were detected. Exposure to cadmium can be one of the factors inducing these changes