28 research outputs found
Epidemiology of Lead Poisoning in Cattle
The case histories of lead poisoning diagnosed in 63 herds of cattle over the past five years were studied. The toxicosis was found to be most prominent during the spring months and resulted in a 61 percent fatality rate. The clinical signs observed involved mainly the central nervous and gastrointestinal systems, as did the post mortem findings. The mean tissue lead levels were determined and correlated with the source of the toxicant
Akutna oralna toksiÄnost organofosfornih insekticida i inhibicija kolinesteraza u piliÄa
Acute toxic effects of three commonly used insecticidal preparations of the organophosphates chlorpyrifos, diazinon, and dichlorvos were examined in mixed breed broiler chicks, and cholinesterase activity in plasma and brain were measured. The acute (24 h) oral median lethal doses (LD50) of chlorpyrifos, diazinon, and dichlorvos were 10.79 mg kg-1, 6.32 mg kg-1, and 6.30 mg kg-1, respectively, as determined by the up-and-down method in chicks. Signs of cholinergic toxicosis in the chicks appeared within two hours after dosing, and they included salivation, lacrimation, gasping, frequent defecation, drooping of wings, tremors, convulsions, and recumbency before death. Halving the oral LD50 of chlorpyrifos (5 mg kg-1), diazinon (3 mg kg-1), and dichlorvos (3 mg kg-1) caused immobility and wing drooping, but not the clinical signs of cholinergic toxicity. However, at full LD50 doses of these insecticides, chicks showed clinical signs of cholinergic toxicity similar to those seen in the LD50 experiments. Two out of six chicks died within two hours after treatment with LD50 doses of chlorpyrifos and dichlorvos, whereas LD50 dosing with diazinon caused death in three out of six chicks. Compared to control values, the insecticides reduced plasma and whole brain cholinesterase activities by 29 % to 84 % and 18 % to 77 %, respectively, depending on the dose. The decrease in plasma cholinesterase correlated well (r = 0.82) with that of the brain. These data suggest that organophosphate insecticides administered orally at LD50 doses induce clinical signs of cholinergic poisoning and concurrently reduce brain and plasma cholinesterase activities in chicks.Ispitano je akutno toksiÄno djelovanje triju Äesto rabljenih organofosfornih insekticida klorpirifosa, diazinona i diklorvosa u brojlera te je izmjerena aktivnost kolinesteraza u njihovoj plazmi i mozgu. Srednja letalna doza LD50 klorpirifosa iznosila je 10,79 mg kg-1, diazinona 6,32 mg kg-1 te diklorvosa 6,30 mg kg-1. Prvi su se znakovi kolinergiÄkoga sindroma u piliÄa javili unutar dva sata od oralne primjene, a obuhvaÄali su slinjenje, suĆŸenje, teĆĄko disanje, uÄestalu defekaciju, objeĆĄena krila, drhtavicu, grÄenje i nesposobnost stajanja uoÄi smrti. Oralna primjena polovice srednje letalne doze insekticida klorpirifosa (5 mg kg-1), diazinona (3 mg kg-1) i diklorvosa (3 mg kg-1) dovela je do nepokretnosti i objeĆĄenih krila, ali bez kliniÄkih znakova kolinergiÄke toksiÄnosti koji su uoÄeni kod pokusa radi utvrÄivanja srednje letalne doze (LD50). MeÄutim, doze ovih insekticida koje su odgovarale LD50, dovele su do kliniÄkih znakova kolinergiÄke toksiÄnosti sliÄnih onima zamijeÄenim kod utvrÄivanja LD50. Dva od ĆĄest piliÄa uginula su unutar dva sata od primjene bilo klorpirifosa bilo diklorvosa u dozama koje su odgovarale LD50, dok je diazinon u odgovarajuÄoj srednjoj letalnoj dozi uzrokovao smrt triju od ĆĄest piliÄa. U odnosu na kontrolne vrijednosti, insekticidi su doveli do smanjenja aktivnosti kolinesteraze koja je ovisila o dozi, a kretala se od 29 % do 84 % u plazmi te od 18 % do 77 % u mozgu. Pad aktivnosti kolinesteraze u plazmi dobro je korelirao s njezinim padom u mozgu (r=0,82). Ovi podaci upuÄuju na to da oralna primjena organofosfornih insekticida u dozama koje odgovaraju srednjoj letalnoj dozi dovode do znakova kolinergiÄkoga trovanja u piliÄa te do istodobnoga pada aktivnosti kolinesteraza u mozgu i plazmi
Plasma and whole brain cholinesterase activities in three wild bird species in Mosul, IRAQ: In vitro inhibition by insecticides
Plasma and brain cholinesterase activities were determined in three wild bird species to assess their exposure to organophosphate and carbamate insecticides which are used in agriculture and public health. In the present study, we used an electrometric method for measurement of cholinesterase activities in the plasma and whole brain of three indigenous wild birds commonly found in northern Iraq. The birds used were apparently healthy adults of both sexes (8 birds/species, comprising 3â5 from each sex) of quail (Coturnix coturnix), collard dove (Streptopelia decaocto) and rock dove (Columba livia gaddi), which were captured in Mosul, Iraq. The mean respective cholinesterase activities (Î pH/30 minutes) in the plasma and whole brain of the birds were as follows: quail (0.96 and 0.29), collard dove (0.97and 0.82) and rock dove (1.44 and 1.42). We examined the potential susceptibility of the plasma or whole brain cholinesterases to inhibition by selected insecticides. The technique of in vitro cholinesterase inhibition for 10 minutes by the organophosphate insecticides dichlorvos, malathion and monocrotophos (0.5 and 1.0 ”M) and the carbamate insecticide carbaryl (5 and10 ”M) in the enzyme reaction mixtures showed significant inhibition of plasma and whole brain cholinesterase activities to various extents. The data further support and add to the reported cholinesterase activities determined electrometrically in wild birds in northern Iraq. The plasma and whole brain cholinesterases of the birds are highly susceptible to inhibition by organophosphate and carbamate insecticides as determined by the described electrometric method, and the results further suggest the usefulness of the method in biomonitoring wild bird cholinesterases
Pets as Sentinels of Human Exposure to Neurotoxic Metals
The idea that animals may be used as sentinels of environmental hazards
pending over humans and the associated public health implications is not a new one.
Nowadays pets are being used as bioindicators for the effects of environmental contaminants
in human populations. This is of paramount importance due to the large
increase in the worldwide distribution of synthetic chemicals, particularly in the
built environment. Companion animals share the habitat with humans being simultaneously
exposed to and suffering the same disease spectrum as their masters.
Moreover, their shorter latency periods (due to briefer lifespans) enable them to act
as early warning systems, allowing timely public health interventions. The rise on
ethical constraints on the use of animals and, consequently, on the sampling they
can be subjected to has led to the preferential use of noninvasive matrices, and in
this case we are looking into hair. This chapter focuses in three non-essential metals:
mercury, lead, and cadmium, due to their ubiquitous presence in the built environment
and their ability of affecting the mammal nervous system. There is a fairly
short amount of studies reporting the concentrations of these metals in petsâ hair,
particularly for cats. These studies are characterized, and the metal concentrations
corresponding to different parameters (e.g., age, sex, diet, rearing) are described in
order to provide the reader with a general vision on the use of this noninvasive
matrix on the studies conducted since the last two decades of the twentieth
century.publishe