acute and chronic exposure
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2022 ◽  
Vol 12 ◽  
Author(s):  
Aleksandra M. Mech ◽  
Munise Merteroglu ◽  
Ian M. Sealy ◽  
Muy-Teck Teh ◽  
Richard J. White ◽  
...  

Developmental consequences of prenatal drug exposure have been reported in many human cohorts and animal studies. The long-lasting impact on the offspring—including motor and cognitive impairments, cranial and cardiac anomalies and increased prevalence of ADHD—is a socioeconomic burden worldwide. Identifying the molecular changes leading to developmental consequences could help ameliorate the deficits and limit the impact. In this study, we have used zebrafish, a well-established behavioral and genetic model with conserved drug response and reward pathways, to identify changes in behavior and cellular pathways in response to developmental exposure to amphetamine, nicotine or oxycodone. In the presence of the drug, exposed animals showed altered behavior, consistent with effects seen in mammalian systems, including impaired locomotion and altered habituation to acoustic startle. Differences in responses seen following acute and chronic exposure suggest adaptation to the presence of the drug. Transcriptomic analysis of exposed larvae revealed differential expression of numerous genes and alterations in many pathways, including those related to cell death, immunity and circadian rhythm regulation. Differential expression of circadian rhythm genes did not correlate with behavioral changes in the larvae, however, two of the circadian genes, arntl2 and per2, were also differentially expressed at later stages of development, suggesting a long-lasting impact of developmental exposures on circadian gene expression. The immediate-early genes, egr1, egr4, fosab, and junbb, which are associated with synaptic plasticity, were downregulated by all three drugs and in situ hybridization showed that the expression for all four genes was reduced across all neuroanatomical regions, including brain regions implicated in reward processing, addiction and other psychiatric conditions. We anticipate that these early changes in gene expression in response to drug exposure are likely to contribute to the consequences of prenatal exposure and their discovery might pave the way to therapeutic intervention to ameliorate the long-lasting deficits.


2021 ◽  
Vol 17 (7) ◽  
pp. 5-9
Author(s):  
V.S. Tkachyshyn

Benzene is a member of the aromatic hydrocarbon group and belongs to the group of blood poisons that cause inhibition of bone marrow hematopoiesis with the development of hypoplastic or aplastic anemia. The benzene can result in acute and chronic intoxication. Under industrial conditions, the penetration of benzene and its homologues into the human body is possible through the lungs and intact skin. The symptoms of changes in the nervous system and bone marrow hematopoiesis in acute and chronic exposure to benzene are different. Acute intoxication manifests itself with symptoms of damage to the central nervous system with the phenomena of general brain disorders, similar to poisoning with substances with narcotic properties. Chronic intoxication develops slowly, unnoticed by the patient, and is characterized by bone marrow damage with impaired blood cell formation. An atypical form of chronic benzene intoxication is the development of benzene leukemia. Therefore, benzene belongs to the group of industrial carcinogens. Typical forms of acute and chronic benzene intoxication are easy to recognize. To establish the diagnosis of benzene intoxication, it is necessary at first to have data confirming the patient’s contact with benzene. Repeated studies of peripheral blood, bone marrow puncture are important. There are no specific antidotes for benzene intoxication. Symptomatic treatment is performed only. Therefore, it is important to prevent the development of benzene intoxication in the workplace before the stage of deep irreversible disorders.


2021 ◽  
Vol 36 (4) ◽  
pp. e2021025
Author(s):  
Alexander Iheanyichukwu Opara ◽  
Casmir Zanders Akaolisa ◽  
Chigozie Osita Akakuru ◽  
Amarachi Udoka Nkwoada ◽  
Francis Chizoruo Ibe ◽  
...  

Numerous particulates are released from the dumpsites in Owerri metropolis and later dispersed to other areas in the environment where they cause adverse health challenges to the inhabitants. To analyze the PM concentration, field measurements were carried out at seven major dumpsites in the Owerri Metropolis. Estimates of the possible health risks as the result of exposure to airborne particulate matter (PM2.5, PM10, etc.) were performed using the US Environmental Protection Agency human health risk assessment framework. A scenario assessment approach in which normal exposure and worst-case scenario were adopted for acute and chronic exposure periods for infants, children, and adults. The concentrations of PM 2.5 which ranged from 122.30-501.76 μg/m3 at the dumpsites exceeded the WHO 24hr annual mean maximum exposure limit. The Nigerian National Ambient Air Quality Standard allowable limit for PM10 was exceeded by most of the dumpsites. Hazard quotient > 1 was exceeded for PM 2.5 by nearly all dumpsites and is likely to cause health challenges. The results showed that under monthly conditions, both PM2.5 and PM10 concentration levels at the dumpsites have the potential to cause adverse health effects when for infants, children, and adults on acute or chronic bases. Actions should be taken to regulate such PM exposure and to raise public awareness for the inhabitants of the affected areas. In conclusion, regular monitoring is therefore needed to decrease the ambient particulate matter (PM) concentrations in the study area.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12486
Author(s):  
Edward A. Straw ◽  
Mark J.F. Brown

Background Glyphosate is the world’s most used pesticide and it is used without the mitigation measures that could reduce the exposure of pollinators to it. However, studies are starting to suggest negative impacts of this pesticide on bees, an essential group of pollinators. Accordingly, whether glyphosate, alone or alongside other stressors, is detrimental to bee health is a vital question. Bees are suffering declines across the globe, and pesticides, including glyphosate, have been suggested as being factors in these declines. Methods Here we test, across a range of experimental paradigms, whether glyphosate impacts a wild bumble bee species, Bombus terrestris. In addition, we build upon existing work with honey bees testing glyphosate-parasite interactions by conducting fully crossed experiments with glyphosate and a common bumble bee trypanosome gut parasite, Crithidia bombi. We utilised regulatory acute toxicity testing protocols, modified to allow for exposure to multiple stressors. These protocols are expanded upon to test for effects on long term survival (20 days). Microcolony testing, using unmated workers, was employed to measure the impacts of either stressor on a proxy of reproductive success. This microcolony testing was conducted with both acute and chronic exposure to cover a range of exposure scenarios. Results We found no effects of acute or chronic exposure to glyphosate, over a range of timespans post-exposure, on mortality or a range of sublethal metrics. We also found no interaction between glyphosate and Crithidia bombi in any metric, although there was conflicting evidence of increased parasite intensity after an acute exposure to glyphosate. In contrast to published literature, we found no direct impacts of this parasite on bee health. Our testing focussed on mortality and worker reproduction, so impacts of either or both of these stressors on other sublethal metrics could still exist. Conclusions Our results expand the current knowledge on glyphosate by testing a previously untested species, Bombus terrestris, using acute exposure, and by incorporating a parasite never before tested alongside glyphosate. In conclusion our results find that glyphosate, as an active ingredient, is unlikely to be harmful to bumble bees either alone, or alongside Crithidia bombi.


Author(s):  
Akram Mahna ◽  
Saeed Solali ◽  
Fateme Akbarbeiglou

Purpose: Magnetic field is one of the effective and non-invasive modalities on biology and angiogenesis. Studies on the effects of magnetic fields on angiogenesis showed that the shape of the magnetic field could potentially affect angiogenesis. Therefore, this study aimed to control the frequency, intensity, and duration of exposure of magnetic field while investigating the effect of the shape of the magnetic field on the viability of Human Umbilical Vein Endothelial Cells (HUVECs). Materials and Methods: The HUVECs were exposed to various shapes of 50 and 60 Hz magnetic fields with intensities of 0.5 and 1 mT in acute and chronic exposure regimes. The viability of HUVECs was assessed via MTT assay. Results: Results showed that the sin type 50 and 60 Hz magnetic fields are more effective in decreasing the viability. The rectified 100 and 120 Hz with 1 and 0.5 mT could increase and decrease the viability compared with 50 and 60 Hz, respectively. Conclusion: It can be concluded that the shape of the magnetic field can be an effective factor in biology and must be controlled to have a reliable response.


Author(s):  
Nnaemeka Okorie ◽  
Emmanuel Ifeanyi Obeagu ◽  
Adaobi Doris Nnamani ◽  
Ugomma Agwu Ude ◽  
Uchechukwu Nelson Agada ◽  
...  

Despite the dangers associated with the increased use of codeine drugs, limited researches have addressed the specific effects of emzolyn codeine on the lung. The aim of this study was to assess the histological effects of emzolyn codeine cough syrup on the lung of Wistar rats and its oxidative stress. Twenty one (21) Wistar rats were divided into 3 groups labeled T1, T2 and T3. Group T1 served as control and was given distilled water and diet for 42 days, group T2 was treated with 0.1 mg/g bodyweight emzolyn codeine cough syrup for 21 days while group T3 was treated with 0.1 mg/g bodyweight emzolyn codeine cough syrup for 42 days. At the end of the duration, the wistar rats were sacrificed under anaesthesia and the lungs were collected after dissection and transferred into 10% buffered formalin. Sections of the lungs were obtained and processed for histological studies using Hematoxylin and Eosin stain, Periodic acid Schiff’s solution, Phosphotungstic acid Haematoxylin stain and Methanamine Silver stains. Results from the study suggested that acute and chronic exposure to emzolyn codeine cough syrup produced significant (P<0.05) decrease in body weight, edematous  aveolar space with marked type 11 pneumocyte, marked hypertrophy (H) of the septa and marked inflammatory cells. The levels of total antioxidant status (TAS) was also determined using standard spectrophotometric techniques. The mean MDA of the exposed groups were significantly higher while the mean levels of SOD, GPx, CAT, and GSH were significantly lower than the control group. In conclusion, this study confirmed the risk of increased oxidative stress, pulmonary toxicity and decreased body weight due to emzolyn codeine cough syrup administration. Thus, indiscriminately and prolong use emzolyn codeine drug should be avoided and antioxidant supplements are advised as a prophylactic supportive therapy for adequate measures in preventing development of oxidative stress-associated complications among exposed individuals.


2021 ◽  
Vol 9 ◽  
Author(s):  
Xiuhui Tian ◽  
Huanjun Li ◽  
Xiuzhen Zhang ◽  
Yingjiang Xu ◽  
Huawei Zhang ◽  
...  

The effects of acute and chronic exposure to semicarbazide were carried out on the sea cucumber Apostichopus japonicus. A half-maximal lethal concentration of 3.72 g/L of semicarbazide hydrochloride (95% confidence interval 3.43–4.02 g/L) was deduced. At 20, 4, and 2% of the half-maximal lethal concentrations, a 28-days exposure induced morphological alterations, oxidative stress, and acetylcholinesterase (AChE) activity in the respiratory tree, intestinal tract, and longitudinal muscle of A. japonicus. Exposure to 20% of the half-maximal lethal concentration resulted in lesions in the respiratory tree and disintegration in the intestinal tract. Exposure to lower concentration induced a gradual accumulation of lesions in the respiratory tree, intestinal tract, and longitudinal muscle. Levels of markers of oxidative stress and neurotransmission, including superoxide dismutase (SOD), catalase, and AChE, were increased during the initial days of exposure and then decreased. The activity of SOD, catalase, and AChE were highest in A. japonicus exposed to 4%, followed by 20 and 2% of the half-maximal lethal concentration at the same time. At the later stages of the 28-days exposure, marker levels were decreased and close to levels in the control groups. Non-targeted metabolomics indicated that significantly different metabolites were screened out, 28 in the positive ion mode and 38 in the negative ion mode, impairments in neurological function, osmotic pressure regulation, energy metabolism, and protein digestion and absorption following exposure of A. japonicus to semicarbazide. KEGG pathway enrichment showed that the exposure affected pathways related to ABC transporters, central carbon metabolism in cancer, protein digestion and absorption, aminoacyl-tRNA biosynthesis, and biosynthesis of unsaturated fatty acids.


2021 ◽  
pp. 7-11
Author(s):  
V. R. Chavan

Lead is one of the elements that can be described as purely toxic. Lead displaces biologically important metals interfering with a variety of body's chemical reactions. A variety of environmental contaminants including heavy metals interfere the endocrine axis of fish. Lead is reported with endocrine disruptive potential. Lead affects the hypothalamus pituitary gonadal axis at multiple sites. In the present work an effort is made to explore qualitative changes in the pituitary gland cell types of Cirrhinus mrigala after an acute and chronic exposure to lead. The study revealed the toxic effects of lead on endocrine functions of a teleost which further affects the fecundity of fish. The present study provides a manifold confirmation on the endocrine disrupting effects of lead in fish


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