lethal doses
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MAUSAM ◽  
2021 ◽  
Vol 60 (2) ◽  
pp. 197-210
Author(s):  
ARUN KUMAR ◽  
S. K. DASH ◽  
S. K. DHAKA

Hazards for a fossil fired power plant located at   coastal Gujarat in India have been assessed.  The trajectory and spread of the plume from tanks of fossil fired power plant were predicted using existing models named Carter, Mills, Briggs and Zonato during winter and summer seasons with low and high wind speeds observed in day and night hours. Results show that wide areas of habitation and human settlement to the northeast of the site may be potentially under hazards due to southwesterly and southerly winds during summer. Plume heights and widths are found high in the morning hours or late night when wind speeds are low. As wind speed increases around noon, low plume heights and widths are obtained.   Length scales become low at low wind speeds and vice-versa. Lethal doses of thermal radiation beyond radial distance of 70 m are within the tolerable limit under hazardous condition.


2021 ◽  
Author(s):  
Mohamed Radwan ◽  
Amira Gad

Abstract Abamectin (avermectin B1, ABM) has been widely used as a biocide in agriculture, veterinary and medicine worldwide. In the current study, we aimed to evaluate the acute toxicity and sub-lethal biochemical responses of ABM on the non-target land snail, Theba pisana. Mortality of snails increased with the dose increase, resulting 48h- LD50 value of 1.048 µg/snail. Sub-lethal effects were studied on the survivors of 20% and 60% LD50 ABM doses and the biochemical parameters were assessed for up to 7 days of exposure. The results showed a decrease in glycogen content and lipids for two sub-lethal doses after all time intervals, whereas increased the level of total proteins after exposure to 60% LD50 ABM. Overall, the tested sub-lethal doses significantly decreased the total energy reserves. ABM-exposure to snails elevated γ-Glutamyl transferase (γ-GT) and Lactate dehydrogenase (LDH) activities at all-time intervals. A significant increase of Glutathione-S-transferase (GST) activity was also recorded in snails exposed to 20% and 60% LD50 after 7 days and all time intervals, respectively. However, ABM inhibited the activity of Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) after 7 days of exposure. Our investigation provides new insights into the disturbances of energy reserves and enzyme activities in T. pisana snails that can be used as useful sentinel organism. Indeed, these tested biochemical parameters of the snails are sensitive and may be used as biomarkers for assessing ABM toxicity.


2021 ◽  
Author(s):  
Margaret R Douglas ◽  
Paige Baisley ◽  
Sara Soba ◽  
Melanie Kammerer ◽  
Eric V Lonsdorf ◽  
...  

Wild and managed pollinators are essential to food production and the function of natural ecosystems; however, their populations are threatened by multiple stressors including pesticide use. Because pollinator species can travel hundreds to thousands of meters to forage, recent research has stressed the importance of evaluating pollinator decline at the landscape scale. However, scientists' and conservationists' ability to do this has been limited by a lack of accessible data on pesticide use at relevant spatial scales and in toxicological units meaningful to pollinators. Here, we synthesize information from several large, publicly available datasets on pesticide use patterns, land use, and toxicity to generate novel datasets describing pesticide use by active ingredient (kg, 1997-2017) and aggregate insecticide load (kg and honey bee lethal doses, 1997-2014) for state-crop combinations in the contiguous U.S. Furthermore, by linking pesticide datasets with land-use data in the contiguous United States, we describe a method to map pesticide indicators at spatial scales relevant to pollinator research and conservation.


2021 ◽  
Vol 32 (8-9) ◽  
pp. 788-788
Author(s):  
N. Kramov

Strychnine antidotes. Haggarda. Greenberg report (I. Amer. MA t. 98, No. 14) that apomorphine in doses of 0.0065-0.013. injected under the skin in cases of human poisoning with lethal doses of strychnine, it gave relief from convulsions and other symptoms of poisoning and led to complete recovery (3 case histories are given).


Biomédica ◽  
2021 ◽  
Vol 41 (3) ◽  
pp. 449-457
Author(s):  
María M. Pulido-Méndez ◽  
Elvia Azuaje ◽  
Alexis Rodríguez-Acosta

Introduction: The thymus is active mainly during the neonatal and pre-adolescent periods.Objective: To test naïve thymocytes proliferation and monocytes stimulation.Materials and methods: We collected fresh thymus tissue from neonate mice after surgery. Suspension cells were coated onto Ficoll-Hypaque support. The obtained cells (thymocytes) were cultured measuring the proliferation of naïve T cells stimulated by Crotalus durissus cumanensis (Cdc) venom at sub-lethal doses (20 ng). Then, we supplemented the wells with AlamarBlue™ and incubated them for 5 h to test their proliferation. Mononuclear cells from mice peripheral blood were collected and layered onto the support of the Ficoll-Hypaque solution. We added the thymocytes actively dividing (25 x 105 cells) from cultures stimulated with Cdc venom at 20 ng/well to cultured monocytes freshly obtained from the Ficoll-Hypaque separation. Both cell populations were incubated for 36 h until monocytes matured to macrophages.Results: The naïve thymocytes rapidly proliferated after stimulation with the Cdc venom (NTCdc) and these successively induced the maturation and function of monocytes progenitor cells to mature macrophages, which ingested Chinese ink.Conclusions: The naïve thymocytes proliferated by stimulation with the Cdc venom and subsequently the NT/Cdc induced the rapid maturation and function of monocytes progenitor cells becoming mature macrophages with their phenotypic characteristics.


2021 ◽  
Author(s):  
José António Ferraz Gonçalves

Abstract Background Doctors often deal with end-of-life issues other than assisted death, such as incompetent patients and treatment withdrawal, including food and fluids. Methods A link to a questionnaire was sent by email three times, at intervals of one week, to the doctors registered in the Northern Section of the Portuguese Medical Association. Results The questionnaire was returned by 1148 (9%) physicians. This study shows that only a minority of Portuguese doctors were willing to give one or more drugs in lethal doses to cognitively incompetent patients with an incurable, advanced, and progressive disease at the request of a family member or other close person, and even less would do it on their own initiative. Concerning the withdrawal of support of life measures in advanced and progressive diseases at the patient’s request, most doctors were in favor, but much fewer doctors agreed with the suspension of supportive life measures at the request of a family member, another close person, or by their own unilateral decision. However, concerning the suspension of food and fluids, fewer agreed with that action. Portuguese doctors favor the administration of drugs for suffering control, even foreseeing they could shorten life, Conclusion Most doctors in this study respect patients’ autonomy, but do not agree with measures decided by others that have an impact on patients’ survival. They also agree with the administration of drugs for suffering control, even considering the possibility of shortening life.


2021 ◽  
Vol 65 (1) ◽  
pp. 113-117
Author(s):  
Mandana Hosseini ◽  
Jamileh Nowroozi ◽  
Nour Amirmozafari

Persister cells are defi ned as a subpopulation of bacteria in a dormant state with the ability to reduce bacterial metabolism and they are involved in antibiotic tolerance. Toxin-antitoxin (TA) systems have been previously suggested as important players in persistence. Therefore, this study aimed to study the involvement of TA systems in persister cell formation in methicillin-resistant Staphylococcus aureus following antibiotic exposure. Using TADB and RASTA database, two type II TA systems including MazF/MazE and RelE/RelB were predicted in S. aureus. The presence of these TA genes was determined in 5 methicillin-resistant S. aureus isolates and the standard strain S. aureus subsp. aureus N315 using PCR method. To induce persistence, isolates were exposed to lethal doses of ciprofl oxacin and the expression of the studied TA system genes was measured after 5 h using Real-Time PCR. According to our results, all the studied isolates harbored the TA system genes. S. aureus was highly capable of persister cell formation following exposure to sub-MIC of ciprofl oxacin and RT-qPCR showed a signifi cant increase in the expression of the MazEF and RelBE loci, indicating their potential role in antibiotic tolerance. Considering the importance of antibiotic tolerance, further studies on persister cell formation and TA systems involved in this phenomenon are required to effi ciently target these systems.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yau-Tuen Chan ◽  
Ning Wang ◽  
Yibin Feng

AbstractAconitum carmichaeli Debx.-derived herbal medicine has been used for anti-inflammation and anti-arrhythmia purpose for more than two thousand years. It is processed into Chuanwu (Radix Aconiti praeparata) and Fuzi (Radix Aconiti lateralis praeparata) in Traditional Chinese Medicine, which are two useful drugs but with toxic properties. There have been patients poisoned by accidental ingestion of Aconitum plants or misuse of the herbal drug, and this is of great concern to study in-depth. In this review, we provided the traditional and contemporary practice of using Aconitum herbs as medicine, from functions, processing methods to toxicity in ethnomedicine aspects to discuss the underlying connections of traditional and modern understanding on the toxicity of Aconitum plants. We summarized the functions and toxicology of the herbal drugs are analyzed from chemical and clinical aspects, with the help of traditional and modern knowledge of medicine. The medicinal doses and lethal doses determined by researches are summarized, and the usage and processing methods are updated and reviewed in the modern view. In addition, clinical management of poisoned cases using western medicine is discussed. This review provides insights and awareness of safety when using Aconitum-derived herbal medicine, and the application of modern scientific knowledge to optimize the detoxification processes. We suggest the possibility to renew the current standard processing method from the official Pharmacopoeia all over the world.


Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 517
Author(s):  
Gary M. Bucciarelli ◽  
Maren Lechner ◽  
Audrey Fontes ◽  
Lee B. Kats ◽  
Heather L. Eisthen ◽  
...  

Tetrodotoxin (TTX) is a potent neurotoxin that was first identified in pufferfish but has since been isolated from an array of taxa that host TTX-producing bacteria. However, determining its origin, ecosystem roles, and biomedical applications has challenged researchers for decades. Recognized as a poison and for its lethal effects on humans when ingested, TTX is primarily a powerful sodium channel inhibitor that targets voltage-gated sodium channels, including six of the nine mammalian isoforms. Although lethal doses for humans range from 1.5–2.0 mg TTX (blood level 9 ng/mL), when it is administered at levels far below LD50, TTX exhibits therapeutic properties, especially to treat cancer-related pain, neuropathic pain, and visceral pain. Furthermore, TTX can potentially treat a variety of medical ailments, including heroin and cocaine withdrawal symptoms, spinal cord injuries, brain trauma, and some kinds of tumors. Here, we (i) describe the perplexing evolution and ecology of tetrodotoxin, (ii) review its mechanisms and modes of action, and (iii) offer an overview of the numerous ways it may be applied as a therapeutic. There is much to be explored in these three areas, and we offer ideas for future research that combine evolutionary biology with therapeutics. The TTX system holds great promise as a therapeutic and understanding the origin and chemical ecology of TTX as a poison will only improve its general benefit to humanity.


2021 ◽  
Author(s):  
Mbarga Manga Joseph Arsene ◽  
Podoprigora Irina Viktorovna ◽  
Anyutoulou Kitio Linda Davares

The evaluation of medicinal plants toxicity is a prerequisite prior their usage. The vertebrate models used for this purpose are often the object of ethical consideration. Though invertebrate models including Galleria mellonella have shown their ability to be used to assess various products toxicity, to our knowledge, G. mellonella has never been exploited to determine the toxicity of medicinal plants. In this study, the toxicity of hydroalcoholic and aqueous extracts of seven (7) Cameroonian medicinal plants namely leaves of Cymbopogon citratus (DC.) Stapf, Moringa oleifera Lam and Vernonia amygdalina Delile; barks of Cinchona officinalis and Enantia chloranta Oliv; barks and seeds of Garcinia lucida Vesque and leaves and seeds of Azadirachta indica (Neem) were evaluated using the larval form of the Greater Wax Moth (Galleria mellonella). The median lethal doses (LD50), 90% lethal doses (LD90) and 100% lethal doses were successfully determined using the spline cubic survival curves and equations from the data obtained on the survival rate of G. mellonella 24h after the injection with the extracts. The LD50 values varied from 3.90 g/kg bw to >166.67 g/kg bw and the pattern of toxicity observed was in accordance with previous investigations on the plant materials concerned. The results obtained in this study suggest that G. mellonella can be used as a sensitive, reliable, and robust eco-friendly model to gauge the toxicity of medicinal plants. Thus, avoid the sacrifice of vertebrate models often used for this purpose to limit ethical concerns.


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