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Biomedical subjects

L Várnagy

Publications and source records attributed to L Várnagy.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of immersion fluid temperature on the chicken embryo in teratogenicity tests: short communication.

The influence of immersion fluid temperature on the development of the chicken embryo was studied on the day most commonly used for treating incubated eggs in teratological trials. Embryonated eggs were immersed in tap water for 30 min on the 12th day of incubation at 22-25 degrees C or at incubation temperature without a waiting time or after 30 min. The incubation was then continued and the eggs were processed on day 19 of the incubation period. Treatment of eggs at 22-25 degrees C caused a significant increase in embryonic mortality, while the 30-min waiting time did not exert an influence on embryogenesis.

Animals↗
PubMed2000

Histological examination of CAM treated with irritative pesticides.

The potential irritancy of compounds may be detected by observing adverse changes which occur in the chorioallantoic membrane (CAM) of the egg after exposure to tested chemicals. In our experiment irritating pesticides (Fusilade S, Karathene LC) and a technical component of pesticide (Trend) are tested and their effects are examined on tissue structure of CAM. After 10-11 days of incubation of chicken embryos the chorioallantoic membrane becomes trilaminar. The outer layer is chorionic epithelium between the two rows of cuboidal cells, thin-walled vascular sinuses can be found. In the intermediate layer, the mesenchyme, well-developed blood vessels can be seen. The inner layer is formed by allantoic epithelium. After the treatment with Fusilade S the wall of the blood vessels was damaged, and blood diffused from the blood vessels. After the treatment with Karathane LC rupture of the wall of the blood vessels could be seen and blood appeared around the blood vessels. Blood vessels of the yolk sac were frequently damaged under CAM.

Allantoin↗
PubMed2000

In vitro ocular irritation toxicity study of some pesticides.

The use of animals in toxicological screening is a controversial issue. The Draize eye irritation test receives particular criticism because of the injuries inflicted on the test animals. In recent years various in vitro methods have been developed to replace the heavily criticised Draize rabbit eye test for irritation testing. One of the best-studied alternative methods is the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM). In the present studies comparative screening was performed with a set of pesticides to establish parallel data on in vitro (HET-CAM) and in vivo (Draize) results. The tested pesticides included Arelon 500 FW (isoproturon), Banvel 480 (dicamba), Dikamin D (2.4 D), Karathane LC (dinocap), Ronstar (oxadiazon) and Modown 4 F (bifenox). In most cases a good correlation was found between the HET-CAM assessment and results of the Draize rabbit eye test. Although the current form of the HET-CAM test is a valuable prescreen method for predicting the ocular irritation potential of chemicals, and can be used for reducing the number of experimental animals, a number of technical problems must still be addressed before these systems can replace whole animal tests. The HET-CAM test can be a useful component of a battery of tests needed for replacing the Draize rabbit eye test.

Animal Testing Alternatives↗
PubMed1999

Model field study of Sumithion 50 EC and Fusilade S on pheasants.

Toxicological studies on wild animals play an important role in the ecotoxicological examination of pesticides. The applied model tests enable the assessment of toxicological consequences with particular regard to the life and nutrition of wild animals in the ploughed field among plants treated with pesticides. The application of different pesticide formulations on plough-land may pose a simultaneous chemical burden to wild birds. In this model study, manifestations of the interaction between an insecticide and a herbicide were studied in pheasants. The birds were placed on lucerne in cages (48 m2) and sprayed once. The applied doses were: Sumithion 50 EC 1 litre/ha + Fusilade S 6 litres/ha (practical doses) and Sumithion 50 EC 5 litres/ha + Fusilade S 30 litres/ha. The analytically determined pesticide concentration of the lucerne was taken as a basis in the further treatment of fodder. The fodder of pheasants contained the following chemicals: 85 mg/kg Sumithion 50 EC + 510 mg/kg Fusilade S and 425 mg/kg Sumithion 50 EC + 2250 mg/kg Fusilade S. Sporadic deaths observed among the pheasants were of traumatic origin and not due to a toxic effect. The decrease of body weight was significant only at the higher dose levels. Acetylcholinesterase (AChE) activity of the blood decreased significantly in both dose groups. On the basis of the results obtained it can be established that at the dose level used in the practice the pesticides studied do not give rise to a toxic interaction in pheasants.

Acetylcholinesterase↗
PubMed1999

Degradation of some pesticides in avian embryos.

On day 9 or 12 of the hatching period different pesticides (parathion, methyl-parathion, carbendazim, 2,4-D-amine Na, phosmethylane) were applied in ecotoxicological trials. The formulations were either injected into the air space of pheasant, quail or hen eggs or hen eggs were treated by the immersion technique. The residues of pesticides were measured in samples on days 13, 14 and 16 of incubation of chicken and pheasant embryos, while the Japanese quail embryos were analysed on days 10-14 of incubation. Analytical chemistry data showed a varying degradation rate of the compounds in avian embryos of the same species. The residues directly affect the embryos, disturbing their normal development and causing pathophysiological and morphological changes.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1999

Embryonic toxicity of insecticide Sumithion 50 EC and herbicide Fusilade S in pheasants after individual or combined administration.

The purpose of this work was to determine the individual and combined effects of insecticide Sumithion 50 EC (50% fenitrothion) and herbicide Fusilade S (12.5% fluazifop-P-butyl) on the development of pheasant embryos. Eggs were treated by injection of various concentrations of pesticides into the air space on day 12 of incubation. Pathological examination of embryos was carried out on day 23 of the hatching period. Mortality rate, body weight data and morphological alterations were evaluated after the macroscopic examination. The skeletal staining method was used to detect deformities. The two pesticides used in combination moderated the toxic/teratogenic effects of individual treatment.

Animals↗
PubMed1996

Toxicity of the herbicides Flubalex, Fusilade S and Maloran 50 WP to chicken embryos after administration as single compounds or in combination.

The teratogenic effects of three herbicides (Flubalex, Fusilade S and Maloran 50 WP) were studied in chicken embryos. Each of the three test substances was administered on days 0 and 12 of incubation. Treatment was followed by evaluation on day 19. The compounds were injected into the air-chamber of eggs at three different concentrations. The medium concentration corresponded to that usually applied in chemical plant protection. In order to determine the combined toxicity of the three herbicides, the medium concentration of Maloran 50 WP and three different concentrations of Flubalex of Fusilade S each were administered simultaneously at a final volume of 0.1 ml per egg, at similar times. Evaluation was done on day 19. In tests of individual toxicity, after injection on day 0 of incubation Maloran 50 WP and Flubalex caused a significant reduction in body mass, while Maloran 50 WP and Fusilade S resulted in marked embryonic mortality. After injection on day 12, the medium and the highest concentration of Flubalex and the highest concentration of Fusilade S caused a marked increase in embryonic mortality. The developmental anomalies were of sporadic nature: their incidence increased only after Flubalex treatment, irrespective of the time of administration. The combined administration of Maloran 50 WP and Flubalex on day 0 resulted in a significant or marked body mass reduction in all groups. Embryonic mortality increased substantially after treatment with the highest dose of Flubalex, while all three concentrations of the other two herbicides led to similar results. When treatment was performed on day 12, the two highest concentrations of Flubalex and the highest concentration of Fusilade S caused expressed embryonic mortality. The developmental anomalies did not show a dose-dependent effect in any of the test series.

Animals↗
PubMed1995

Effects of repeated oral doses of Dikamin D (2,4-D-amine Na) on rats.

The toxic effects of repeated, increasing oral doses of Dikamin D (72% 2,4-D-amine Na), a broad leave herbicide product used world-wide, were evaluated on rats by the method of Lim et al. (1961). A comparison of the determined acute oral LD50 and the calculated subchronic oral LD50 values revealed a definite tolerance of the experimental animals to the test compound. This finding indicates that repeated oral treatment is capable of increasing the test animal's metabolizing capacity, which accounts for the development of tolerance.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1993

Biochemical examination of muscle samples from pheasant embryos affected by Wofatox 50 EC (50% parathion-methyl).

On day 12 of incubation 0.4% and 4.0% aqueous emulsions of Wofatox 50 EC (50% parathion-methyl) were injected into the air space of pheasant eggs. The eggs were opened on day 23 of the incubation period and samples were obtained from both the cervical and the femoral muscles. Atrophy was detected only in the cervical muscles by light microscopic evaluation. Calcium ion concentration was higher in the cervical musculature, but this parameter did not show significant dose-dependent changes. The activity of creatine kinase (CK) was significantly decreased only in the cervical musculature. The obtained biochemical data might result from a secondary atrophy of the cervical muscles.

Animals↗
PubMed1992

Teratological examination of the insecticide methyl-parathion (Wofatox 50 EC) on pheasant embryos. 2. Biochemical study.

Fertile pheasant's eggs were treated with the insecticide Wofatox 50 EC (50% methyl-parathion) by injection technique on day 12 of the hatching period. Treatment consisted of inoculation of 0.1 ml of different concentrations of the insecticide into the air space of embryonated eggs. The following dose levels were employed: 0.00, 1.35, 13.5 and 135.0 mg/kg egg of active ingredient. Biochemical changes in the plasma were evaluated by micro (photometric) methods which rendered possible the determination of several blood plasma variables of the embryos. At the highest dose level applied, serum alkaline phosphatase (SAP) enzyme activity and inorganic P concentration of the treated embryos showed statistically differences (reduction) as compared to the control data. Macroscopic alterations were detected at necropsy.

Animals↗
PubMed1985

Biochemical study of muscle samples from chicken embryos affected by Wofatox 50 EC.

On day 12 of incubation 0.4% and 4.0% aqueous emulsions of Wofatox 50 EC (50% methylparathion) were injected into the air space of the chicken egg. The eggs were opened on the day 19 of incubation and samples were obtained from both cervical and femoral muscles. Atrophy was found only in the cervical muscles by light microscopic evaluation. It is known that the inhibition of acetylcholine esterase causes a permanent inflow and accumulation of Ca2+ especially in the cervical muscle due to the increased mass and energy utilization in the last period before hatching. Changes in the activity of creatine kinase were expressed in a decreased creatine and creatine-phosphate content.

Abnormalities, Drug-Induced↗
PubMed1985

Comparative teratological study of insecticide Wofatox 50 EC (50% methyl-parathion) on chicken and pheasant fetuses.

An experimental insecticide Wofatox 50 EC, injected into the embryonated eggs from hens and pheasants at 12th day of incubation, caused a significantly diminished body mass, a high incidence of developmental malformations and embryonic mortalities at higher dose-levels. The lower, in plant protection practice used concentration was no teratogenic or lethal on embryos.

Abnormalities, Drug-Induced↗
PubMed1985

Teratological examination of Wofatox 50 EC (50% methylparathion) on pheasant embryos.

Wofatox 50 EC is a widely used experimental insecticide, which can expose the pheasants (non-target organisms) during the plant protection practice. The test material was employed in 4 different aqueous emulsions, of which the 2 lowest level (0.2 and 0.4%) corresponded to the concentrations used in plant protection. The total volume of injected emulsions was 0.1 ml per egg on the 12th d of incubation. The macroscopic results showed a dose-dependent maldevelopment (generally cervical lordosis and scoliosis, cyllosis and sporadic thoraco-gastroschisis).

Abnormalities, Drug-Induced↗
PubMed1984

Teratological examination of the insecticide methylparathion (Wofatox 50 EC) on pheasant embryos. 1. Morphological study.

Teratogenic effects of methylparathion / Wofatox 50 EC/ and Parathion 20 WP as positive control material were tested in pheasant embryos. On the 12th day of incubation 0.1 ml of the emulsions or suspensions of the insecticides at different concentrations was inoculated into the air space of embryonated eggs. The following dose levels were employed: 27 and 270 mg/kg egg of Wofatox 50 EC, and 10 mg/kg of Parathion 20 WP. Morphological changes were evaluated by macroscopic, skeletal staining and light microscopic examinations of the embryos. Primary hypoplasia or atrophy developed in the cervical musculature /m. longus colli/ accompanied by lordosis and scoliosis of the cervical spine. In most cases we also found cyllosis .

Abnormalities, Drug-Induced↗