Rare earth elements in human and animal health: State of art and research priorities

"Background: A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects. Methods: A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects. Results: Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted. Conclusion: The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments. (C) 2015 Elsevier Inc. All rights reserved.

Effects of saliva and nasal secretion on some physical properties of four different resin materials

Objective: Aim of this study was to evaluate possible effects of saliva and nasal secretion on some physical properties, such as sorption, solubility, surface hardness and colour change on four different resin-based materials over a certain time period. Materials and Methods: A total of 128 disc-shaped specimens with a diameter of 50mm and thickness of 0.5mm were tested to evaluate sorption and solubility (ISO-1567). The specimens were stored in different solutions prior to testing. Surface hardness measurements were performed by using a Vickers hardness testing machine. A total of 20 cylindershaped test specimens with a diameter of 13 mm and thickness of 1 mm were prepared to evaluate colour change (?E). Analysis of variance was used to determine significant differences among groups. Paired t and Tukey Post-Hoc tests were performed to investigate significant differences among subgroups at all time intervals (p<0.05). Results: It was found that while the percentage absorption value at T7(7 days) of the auto-polymerizing (A) groups storaged in artificial saliva + nasal secretion were the highest (0.057±0.119), the percentage absorption value at T15(15 days) of the D groups storaged in artificial nasal secretion were the lowest (0.013±0.09). Besides, it was found that the percentage solubility value at T30(30 days) of visible ligth-cusing resin (VLC) groups storaged in artificial nasal secretion were the highest (0.016±0.003), and the percentage solubility value at T1(1 day) of the D groups storaged in distilled water were the lowest (0.01±0.02). While the highest hardness value was of T0(Dry) in group heat-polymerizing (H) (36.19±1.35), the lowest hardness value was of T0 in group D (9.83±2.48). When ?E values analysed for each group, VLC group showed the highest values (23.78±5.05) (p<0.05), group D showed the lowest values (9.06±2.82) in time (between the T0 and T30). Conclusion: The new polyamide resin was observed to show better physical properties when compared with other materials

Comparative toxicities of selected rare earth elements: Sea urchin embryogenesis and fertilization damage with redox and cytogenetic effects

Background: Broad-rangingadverseeffectsareknownforrareearthelements(REE),yetonlyafew studies testedthetoxicityofseveralREE,promptingstudiesfocusingonmulti-parameterREEtoxicity. Methods: TrichloridesaltsofY,La,Ce,Nd,Sm,EuandGdweretestedin Paracentrotuslividus sea urchin embryos andspermfor:(1)developmentaldefectsineitherREE-exposedlarvaeorintheoffspringof REE-exposedsperm;(2)fertilizationsuccess;(3)mitoticanomaliesinREE-exposedembryosandinthe offspring ofREE-exposedsperm,and(4)reactiveoxygenspecies(ROS)formation,andmalondialdehyde (MDA)andnitricoxide(NO)levels. Results: REEs affected P.lividus larvaewithconcentration-relatedincreaseindevelopmentaldefects, 106 to 104 M, rankingas:Gd(III)4Y(III)4La(III)4Nd(III)≅Eu(III)4Ce(III)≅Sm(III). Nominalcon- centrations ofREEsaltswereconfirmed byinductivelycoupledplasmamassspectrometry(ICP-MS). Significant increasesinMDAlevels,ROSformation,andNOlevelswerefoundinREE-exposedembryos. Sperm exposuretoREEs(105 to 104 M) resultedinconcentration-relateddecreaseinfertilization success alongwithincreaseinoffspringdamage.Decreasedmitoticactivityandincreasedaberration ratesweredetectedinREE-exposedembryosandintheoffspringofREE-exposedsperm. Conclusion: REE-associated toxicityaffectingembryogenesis,fertilization,cytogeneticandredoxend- points showeddifferentactivitiesoftestedREEs.Damagetoearlylifestages,alongwithredoxandcy- togeneticanomaliesshouldbethefocusoffutureREEtoxicitystudies

Resolving the effects of environmental micro- and nanoplastics exposure in biota: A knowledge gap analysis

The pervasive spread of microplastics (MPs) and nanoplastics (NPs) has raised significant concerns on their toxicity in both aquatic and terrestrial environments. These polymer-based materials have implications for plants, wildlife and human health, threatening food chain integrity and ultimate ecosystem resilience. An extensive – and growing – body of literature is available on MP- and NP-associated effects, including in a number of aquatic biota, with as yet limited reports in terrestrial environments. Effects range from no detectable, or very low level, biological effects to more severe outcomes such as (but not limited to) increased mortality rates, altered immune and inflammatory responses, oxidative stress, genetic damage and dysmetabolic changes. A well-established exposure route to MPs and NPs involves ingestion with subsequent incorporation into tissues. MP and NP exposures have also been found to lead to genetic damage, including effects related to mitotic anomalies, or to transmissible damage from sperm cells to their offspring, especially in echinoderms. Effects on the proteome, transcriptome and metabolome warrant ad hoc investigations as these integrated “omics” workflows could provide greater insight into molecular pathways of effect. Given their different physical structures, chemical identity and presumably different modes of action, exposure to different types of MPs and NPs may result in different biological effects in biota, thus comparative investigations of different MPs and NPs are required to ascertain the respective effects. Furthermore, research on MP and NP should also consider their ability to act as vectors for other toxicants, and possible outcomes of exposure may even include effects at the community level, thus requiring investigations in mesocosm models

Hormetic effects of cerium, lanthanum and their combination at sub-micromolar concentrations in sea urchin sperm

Rare earth elements (REEs) cerium and lanthanum and their combination were tested across a concentration range, from toxic (10-4 to 10-5 M) to lower concentrations (10-6 to 10-8 M) for their effects on sea urchin (Sphaerechinus granularis) sperm. A significantly decreased fertilization rate (FR) was found for sperm exposed to 10-5 M Ce, La and their combination, opposed to a significant increase of FR following 10-7 and 10-8 M REE sperm exposure. The offspring of REE-exposed sperm showed significantly increased developmental defects following sperm exposure to 10-5 M REEs vs. untreated controls, while sperm exposure to 10-7 and 10-8 M REEs resulted in significantly decreased rates of developmental defects

Selenat, selenit ve seleno-DL-metionin'in paracentrotus lividus (Lamarck, 1816) üzerine embriyotoksik ve genotoksik etkilerinin araştırılması

VI ABSTRACT INVESTIGATION OF EMBRYOTOXIC AND GENOTOXIC EFFECTS OF SELENATE, SELENITE AND SELENO-BL-METHIONINE ON Paracentrotus lividus (LAMARCK, 1816) ORAL, Rahime DSc. in Biology Supervisor : Prof. Dr. Hüseyin Uysal September 1997, 100 pages As a result of antropogenic activities, selenium input to the marine ecosystem has been increased in the recent years. Therefore, especially the river mouths and the coastal areas nearby of industrial discharge outfalls are affected negative way by this element. In this study comparative embryotoxic and genotoxic effects of increasing concentrations (10"7M-3xlO"5M) of selenate (Se04), selenite (SeOa) and seleno-DL-methionine (CsHnNC^Se), were tested on the gametes and embryos of Paracentrotus lividus, living in the littoral areas, which are the dominant echionoid species in the Mediterranean and northeast Atlantic Ocean. Results were evaluated by observing : (a) larval malformations; (b) developmental arrest; (c) embryonic / larval mortality; (d) sperm fertilization success, (e) quantitative and morphologic changes in mitotic activity. Data indicated stimulation in fertilization success of Paracentrotus lividus increase in. the fertilization ratios by about 17 % all tested concentrations without any significant variations of all chemical forms of selenium. However, it was observed significant increases on the pluteus larvae percentages, having especially skeleton malformations on the offspring of the same sperms cultured for 72 hours under optimum conditions compared with control base, and as a result of embryotoxic analysis, the spermiotoxic level were determined to be 10"6 M for selenate, 3xl0"7 M for selenite and 10"7 M for seleno-DL-methionine for this species. But, the embryotoxic level for the same species were determined tovıı be 10"6 M for selenate, 3xl0"7 M for selenite and seleno-DL-methionine. Result of embryological analysis, while low concentrations of all selenium forms generally caused malformations in skeleton systems, it was observed that high concentrations stopped the growth of embryos at the early stages (blastula and gastrula) by preventing mitosis. Cytogenetic analysis indicated that the mitotic indexes were decreased with increasing concentrations of all selenium forms and in opposition to this they caused quantitative parameters by increasing interphase embryo rations. Also it was observed that various mitotic aberrations were increased as especially lagging chromosomes, anaphase bridges and scattered chromosomes. The arrangement of comparative selenium toxicity of seleno-DL- methionine > selenite > selenate was observed during all the tests on P. lividus embryos. Under the light of all these data, it has been reached the conclusion that selenium affects the P. lividus during reproduction and embryonic growth stages at the population level and therefore ecologically important. Keywords: Selenate, selenite, seleno-DL-methionine, Paracentrotus lividus, spermiotoxicity, embryotoxicity, genotoxicity.IV ÖZET SELENAT, SELENİT VE SELENO-DL-METİONÎNfİN Paracentrotus Hvidııs (LAMARCK, 1816) ÜZERİNE EMBRİYOTOKSİK VE GENOTOKSİK ETKİLERİNİN ARAŞTIRILMASI ORAL, Rallime Doktora Tezi, Biyoloji Anabilim Dalı Tez Yöneticisi : Prof. Dr. Hüseyin Uysal Eylül 1997, 100 sayfa Antropojenik aktiviteler sonucunda denizel ekosisteme giren selenyum miktarları son yıllarda artış göstermektedir. Bu nedenle özellikle nehir ağızlan ile endüstriyel deşarjlara yakın kıyışa! bölgeler bu elementten olumsuz yönde etkilenmektedir. Bu çalışmada selenat (SeC>4), selenit (SeOj) ve seleno-DL- metioninin (C5HnN02Se) artan konsantrasyonlarını (10"7M-3xl0"5M) karşılaştırmalı embriyotoksik ve genotoksik etkileri Akdeniz'de ve Atlantik Okyanusu'nun kuzeydoğusunda dominant ekinoid türü olan ve littoral bölgede yaşayan Paracentrotus Uvidus'wL gamet ve embriyoları kullanılarak belirlenmeye çalışılmıştır. Sonuçlar : a) larval bozukluklar; b) gelişim geriliği; c) embriyonik / larval ölüm; d) sperm fertilizasyon başarısı; e) mitotik aktivitede sayısal ve morfolojik değişikliklere bakılarak değerlendirilmiştir. Veriler, test edilen tüm konsantrasyonlarda önemli farklılık göstermeyecek şekilde selenyumun tüm kimyasal formlarının P. lividus spermlerinin fertilizasyon başarısını stimüle ederek, fertilizasyon oranım yaklaşık % 17 arttırdığım göstermiştir. Bununla birlikte aynı spermlerin 72 saat süreyle optimum koşullarda yetiştirilen döllerinde kontrollere oranla özellikle iskelet bozukluklarına sahip pluteus larvası yüzdesinde önemli artışların olduğu gözlenmiş ve embriyotoksik analizler sonucunda bu tür için spermiyotoksik seviye selenat için 10"6 M, selenit için 3x1 0"7 M, ve seleno-DL-metionin için 10"7. M olarak belirlenmiştir, fakat aynı türiçin embriyotoksik seviye İO^.M selenat, 3xlO"7M selenit ve seleno-DL-metionin olarak saptanmıştır. Embriyolojik analizler sonucunda selenyumun tüm formlarının düşük konsantrasyonlarının genellikle iskelet sisteminde deformasyonlar oluştururken yüksek konsantrasyonlarının bölünmeyi engelleyerek embriyoların erken safhalarda (blastula ve gastrula) gelişiminin durdurulmasına neden olduğu gözlenmiştir. Sitogenetik analizler ise selenyumun tüm formlarının artan konsantrasyonlarına paralel olarak mitotik endeksi azalttığı buna karşılık interfaz embriyo yüzdesini arttırarak sayısal ölçütlerde değişikliklere neden olduğu bununla birlikte özellikle kalan kromozom, anafaz köprüsü ve serbest kromozom olmak üzere çeşitli mitotik bozuldukların artışına neden olduğu görülmüştür. P. lividus embriyoları ile gerçekleştirilen tüm denemeler sonucunda selenyumun karşılaştırmalı toksisitesinde seleno-DL- metionin > selenit > selenat sıralaması görülmüştür. Tüm bu veriler ışığında selenyumun P. lividus'xm üreme ve embriyonik gelişimi üzerinde görülen bu zararlı etkilerinin selenyumun bu türü populasyon seviyesinde etkilemesi nedeniyle ekolojik önem taşıdığı sonucuna varılmıştır

Selenat,selenit ve seleno-DL-metionin'in Paracentrotus lividus (Lamarck,1816) üzerine spermiyotoksik ve emriyotoksik etkilerinin araştırılması

Investigation of spermiotoxic and embryotoxlc effects of selenate, selenite and seleno-DL-methionine on Paracentrotus lividus (Lamarck, 1816): In this study comparative spermiotoxic and embryotoxic effects of increasing concentrations $(10^{-7}M -3x10^{-5}M)$ of selenate, selenite and seleno-DL-methionine were tested on the gametes and embryos of P. lividus. Data indicated a stimulation in the fertilization success of P. lividus sperms and an increase in the fertilization ratios by about 17 % in all tested concentrations without any significant variations of all chemical forms of selenium. However, significant increases were observed in percentages of the pluteus larvae, having especially skeleton malformations on the offspring of the same sperms cultured for 72 -hours under optimum conditions compared with control base. As a result of embryological analysis, the spermiotoxic level were determined to be $10^{-6}$ for selenate, $3x10^{-7}M$ for selenite and $10^{-7}$ for seleno-DL-methionine for this species. But, the embryotoxic level for the same species were determined to be $10^{-6}$ for selenate, $3x10^{-7}M$for selenite and seleno-DL-methionine. The arrangement of comparative selenium toxicity of seleno-DL-methionine ;gt; selenite ;gt; selenate was observed during all the tests on P. lividus embryos.Bu çalışmada selenat, selenit ve seleno-DL-metioninin artan konsantrasyonlarının $(10^{-7}M -3x10^{-5}M)$ karşılaştırmalı spenniyotoksik ve embriyotoksik etkileri P. lividus' un gamet ve embriyoları kullanılarak belirlenmeye çalışılmıştır. Veriler, test edilen tüm konsantrasyonlarda önemli farklılık göstermeyecek şekilde selenyumun tüm kimyasal formlarının P. lividus spermlerinin fertilizasyon başarısını şümule ederek, fertilizasyon oranını yaklaşık % 17 oranında arttırdığını göstermiştir. Bununla birlikte aynı spermlerin 72 saat süreyle optimum koşullarda yetiştirilen döllerinde kontrollere oranla özellikle iskelet bozukluklarına sahip pluteus larvası yüzdesinde önemli artışların olduğu gözlenmiştir. Embriyolojik analizler sonucunda bu tür için spermiyotoksik seviye selenat için $10^{-6}$ M, selenit için $3x10^{-7}M$, ve seleno-DL-metionin için $10^{-7}$ M olarak belirlenmiştir. Ancak aynı tür için embriyotoksik seviye $10^{-6}$ M selenat, $3x10^{-7}M$ selenit ve seleno-DL-metionin olarak saptanmıştır. P. lividus embriyoları ile gerçekleştirilen tüm denemeler sonucunda selenyuhıun karşılaştırmalı toksisitesinde seleno-DL-metionin > selenit > selenat sıralaması görülmüştür

İzmir Körfezi'nin ekolojik olarak stresli bölgelerinin toksisitesi

Toxicities of waters and sediments of Izmir Bay which is known as extensively polluted by anthropogenic activities were investigated using sea urchin, Paracentrotus lividus (Lamarck, 1816), the dominant echinoid species of the Mediterranean. Emryotoxicity was studied by assessing developmental defects in embryo exposed to waters and sediments were sampled five sites in inner part of Izmir Bay. In the results of microscopic analysis of larvae or embryos exposed to waters or sediments during emryogenesis (from zigot up to pluteus larval stage),except one site which was almost near reference site both water and sediments samples from other four sites were determined that they had embryotoxic effects on sea urchin.Antropojenik faaliyetler sonucunda çok yoğun bir şekilde kirli olduğu bilinen izmir Körfezi'nin su ve sedimentlerinin toksisitesi, Akdeniz'de dominant ekinoid türü olan deniz kestanesi Paracentrotus lividus (Lamarck, 1816) kullanılarak araştırılmıştır. Izmir Körfezi'nin İç Körfez bölümünden beş istasyondan alman su ve sediment örneklerine maruz kalan embriyolarda gelişim bozukluklarına bakılarak embriyotoksisite araştırılmıştır. Embriyogenezis süresince (zigot oluşumundan pluteus larval safhasına kadar) su ve sedimentlere maruz bırakılan embriyo ya da larvaların mikroskobik analizi sonucunda, kontrol istasyonuna nispeten yakın olan bir istasyon dışında diğer dört istasyonun hem su ve hem de sedimentlerinin deniz kestanesi üzerine embriyotoksik etkiye sahip olduktan saptanmıştır