scholarly journals A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species—A Critical Review

2017 ◽  
Vol 18 (10) ◽  
pp. 2209 ◽  
Author(s):  
Bozena Hosnedlova ◽  
Marta Kepinska ◽  
Sylvie Skalickova ◽  
Carlos Fernandez ◽  
Branislav Ruttkay-Nedecky ◽  
...  
Ecology ◽  
2012 ◽  
Vol 93 (10) ◽  
pp. 2241-2252 ◽  
Author(s):  
Jarrod Cusens ◽  
Shane D. Wright ◽  
Paul D. McBride ◽  
Len N. Gillman

2000 ◽  
Vol 89 (6) ◽  
pp. 2107-2116 ◽  
Author(s):  
R. S. Lillo ◽  
E. C. Parker

A mixed-gas model for rats was developed to further explore the role of different gases in decompression and to provide a global model for possible future evaluation of its usefulness for human prediction. A Hill-equation dose-response model was fitted to over 5,000 rat dives by using the technique of maximum likelihood. These dives used various mixtures of He, N2, Ar, and O2 and had times at depth up to 2 h and varied decompression profiles. Results supported past findings, including 1) differences among the gases in decompression risk (He < N2 < Ar) and exchange rate (He > Ar ≈ N2), 2) significant decompression risk of O2, and 3) increased risk of decompression sickness with heavier animals. New findings included asymmetrical gas exchange with gas washout often unexpectedly faster than uptake. Model success was demonstrated by the relatively small errors (and their random scatter) between model predictions and actual incidences. This mixed-gas model for prediction of decompression sickness in rats is the first such model for any animal species that covers such a broad range of gas mixtures and dive profiles.


1981 ◽  
Vol 3 (2) ◽  
pp. 129-164 ◽  
Author(s):  
Vitor F. Weinman ◽  
A. Bernard Ackerman

2018 ◽  
Vol 7 (1) ◽  
pp. 69-93 ◽  
Author(s):  
Abdullah Scott ◽  
Krishna Prasad Vadalasetty ◽  
André Chwalibog ◽  
Ewa Sawosz

AbstractCopper (Cu) is a vital trace element involved in various physiological and biochemical processes. However, animals can only absorb a small fraction of Cu and the most is excreted, contaminating soil and aquatic environment. Hence, the use of this mineral as a growth promoter is today one of the crucial health and environmental concerns. In recent years, many studies have reported Cu nanoparticles (Cu-NP) as a promising alternative to antibacterial reagents and a growth promoter. Depending on the size, shape, dose and animal species, Cu-NP exhibit a variety of effects on animal performance. Apart from being highly bioavailable, reports have already pointed out the growth-promoting, antibacterial and immune-modulatory effects of Cu-NP. Toxicological studies provide varied results in animal models. However, other studies being undertaken in different animal species have shown the promise of Cu-NP supplementation. Therefore, there is a need to optimise the dose and duration of Cu-NP supplementation for livestock, depending on their biological effects. Moreover, the bioavailability of Cu-NP in livestock still needs further confirmation. In this review, we summarise the benefits and hazardous effects of Cu-NP and the possibility of using Cu-NP as a feed supplement in different animals, in general, and in poultry particularly.


Author(s):  
Aleksandra Fucic ◽  
Radu Duca ◽  
Karen S. Galea ◽  
Tihana Maric ◽  
Kelly Garcia ◽  
...  

A marked reduction in fertility and an increase in adverse reproductive outcomes during the last few decades have been associated with occupational and environmental chemical exposures. Exposure to different types of pesticides may increase the risks of chronic diseases, such as diabetes, cancer, and neurodegenerative disease, but also of reduced fertility and birth defects. Both occupational and environmental exposures to pesticides are important, as many are endocrine disruptors, which means that even very low-dose exposure levels may have measurable biological effects. The aim of this review was to summarize the knowledge collected between 2000 and 2020, to highlight new findings, and to further interpret the mechanisms that may associate pesticides with infertility, abnormal sexual maturation, and pregnancy complications associated with occupational, environmental and transplacental exposures. A summary of current pesticide production and usage legislation is also included in order to elucidate the potential impact on exposure profile differences between countries, which may inform prevention measures. Recommendations for the medical surveillance of occupationally exposed populations, which should be facilitated by the biomonitoring of reduced fertility, is also discussed.


2006 ◽  
Vol 85 (10) ◽  
pp. 870-877 ◽  
Author(s):  
H. Schweikl ◽  
G. Spagnuolo ◽  
G. Schmalz

Monomers are released from dental resin materials, and thus cause adverse biological effects in mammalian cells. Cytotoxicity and genotoxicity of some of these methacrylates have been identified in a vast number of investigations during the last decade. It has been well-established that the co-monomer triethylene glycol dimethacrylate (TEGDMA) causes gene mutations in vitro. The formation of micronuclei is indicative of chromosomal damage and the induction of DNA strand breaks detected with monomers like TEGDMA and 2-hydroxyethyl methacrylate (HEMA). As a consequence of DNA damage, the mammalian cell cycle was delayed in both G1 and G2/M phases, depending on the concentrations of the monomers. Yet, the mechanisms underlying the genetic and cellular toxicology of resin monomers have remained obscure until recently. New findings indicate that increased oxidative stress results in an impairment of the cellular pro- and anti-oxidant redox balance caused by monomers. It has been demonstrated that monomers reduced the levels of the natural radical scavenger glutathione (GSH), which protects cell structures from damage caused by reactive oxygen species (ROS). Depletion of the intracellular GSH pool may then significantly contribute to cytotoxicity, because a related increase in ROS levels can activate pathways leading to apoptosis. Complementary, cytotoxic, and genotoxic effects of TEGDMA and HEMA are inhibited in the presence of ROS scavengers like N-acetylcysteine (NAC), ascorbate, and Trolox (vitamin E). Elevated intracellular levels of ROS can also activate a complex network of redox-responsive macromolecules, including redox-sensitive transcription factors like nuclear factor kappaB (NF-κB). It has been shown that NF-κB is activated probably to counteract HEMA-induced apoptosis. The induction of apoptosis by TEGDMA in human pulp cells has been associated with an inhibition of the phosphatidylinositol 3-kinase (PI3-K) cell-survival signaling pathway. Although the details of the mechanisms leading to cell death, genotoxicity, and cell-cycle delay are not completely understood, resin monomers may be able to alter the functions of the cells of the oral cavity. Pathways regulating cellular homeostasis, dentinogenesis, or tissue repair may be modified by monomers at concentrations well below those which cause acute cytotoxicity.


Development ◽  
1975 ◽  
Vol 33 (4) ◽  
pp. 1051-1066
Author(s):  
par C. Mathieu ◽  
A. M. Duprat ◽  
M. H. Dupuy ◽  
P. Ferrer ◽  
J. P. Zalta ◽  
...  

Biological effects of solutions of non-histone chromatin-associated proteins on cell differentiation in vitro Nuclear non-histone (NNH) proteins, both chromatin-associated and otherwise, have been prepared in defined conditions, either from nuclei or from washed chromatin. When these NNH proteins are homospecific, they produce inhibitory effects on morphological differentiation of embryonic Urodelan Amphibian cells cultivated in vitro. When they are heterospecific, on the contrary, they have no action on the differentiation of those cells. It is concluded that the effects of the non-histone proteins on cell differentiation depend upon the relationship between the animal species which is used to provide the proteins and that used to provide the reactive material.


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