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Biomedical subjects

E Arias

Publications and source records attributed to E Arias.

35 records · Page 2Linked to original sources
PubMed1986

The toxicity of 2,4-dichlorophenoxyacetic acid to the adult crested newt.

The toxicity of the herbicide Agroxone 5, a commercial formulation of the iso-octyl ester of 2,4-dichlorophenoxyacetic acid (2,4-D), in the adult crested newt (Triturus cristatus carnifex) was tested after percutaneous exposure. The compound was lethal to all the animals within 72 hr at concentrations of 100, 125, and 150 ppm. Males appeared to be more susceptible than females to the toxic effects of 2,4-D, since the LT50 values at 75 ppm were 102 and 132 hr for male and female newts, respectively. At 50 ppm, all the males died within 31 days of exposure, whereas the females were still alive at the end of the 3-month experiment. Only one male died at 25 ppm after 21 days. Vacuolar degeneration of liver parenchyma and necrosis of kidney tubules were found at lethal concentrations of 2,4-D. The severity of the lesions was related to the duration of exposure more than to the concentration of the herbicide.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1986

Toxicity of 2-methyl-4-chlorophenoxyacetic acid to the adult crested newt.

The toxicity of the herbicide Agroxone 3, a commercial formulation of the sodium salt of 2-methyl-4-chlorophenoxyacetic acid (MCPA), in the adult newt (Triturus cristatus carnifex) was tested after percutaneous exposure. At the concentration of 3200 ppm, the LT50 values were 17 and 21 hr for male and female newts. At 1600 ppm, the LT50 values were 35 and 45.5 hr. At 800 ppm, most of the animals were still alive after the 3 months of experimentation. There were no deaths at 400 and 200 ppm. Severe neuromuscular disorders were observed in animals exposed to lethal concentrations.

2-Methyl-4-chlorophenoxyacetic Acid↗
PubMed1984

Abnormal limb regeneration in adult newts exposed to the fungicide Maneb 80. A histological study.

The effects of the fungicide Maneb 80 (manganese ethylenebisdithiocarbamate, 80% active ingredient) on the regenerating limb of the adult crested newt, Triturus cristatus carnifex, was studied. Female newts were exposed percutaneously to 5 ppm Maneb 80. One group of control newts was exposed to the inert ingredients of Maneb 80 (sodium lignin sulfonate and n-butylnaphthalene sulfonate), and another control group was kept in tap water. The limbs were examined histologically at weekly intervals throughout the regeneration period and at the end of the experiment (10-12 wk postamputation). The regenerating limbs of all the animals exposed to Maneb 80 showed growth retardation and skeletal abnormalities. Histological examination provided evidence that vascular disturbances are important for the genesis of the developmental abnormalities induced by Maneb 80. The inert ingredients had a promoting effect on limb growth and had no teratogenic effects under our experimental conditions. There were no histological differences between the two control groups.

Abnormalities, Drug-Induced↗
PubMed1982

Chromosome variation in two populations of the crested newt, Triturus cristatus carnifex, with different melanoma incidence.

Morphometric analysis of the chromosomes of the crested newt, Triturus cristatus carnifex, was carried out for two populations, one from Rosate (Milan) and one from Bagnaia (Perugia), which differed in the prevalence of melanoma (2.9 and 0.8%, respectively). Chromosomes were arranged in pairs both by the cytologist and by a previously developed computer programme. The two populations had significant differences in the relative lengths of chromosomes 9 and 10, and in the arm ratio values of 6 and 11. Though the morphometric parameters of the other elements of the complement appeared to be similar, the Rosate population showed significantly higher chromosomal asymmetry. In the Rosate population, there was greater intra-population and intra-individual variability than in the Bagnaia population. The karyotype variations observed suggest that chromosomal rearrangement may have occurred.

Analysis of Variance↗
PubMed1981

The merits of special antenatal care for twin pregnancies.

A combined series of 101 twin pregnancies for whom routine hospital rest during the last trimester was replaced by intensified antenatal care in a special twins clinic was studied. Perinatal mortality and morbidity was similar to that found in a comparison group of 137 twin pregnancies under the care of consultants and not referred to the twins clinic. Routine cervical assessments and uterine activity measurements were unhelpful in predicting premature delivery. Urinary oestrogens and ultrasonic measurements of fetal biparietal diameter were of little or no value in predicting weight for gestational age but the ultrasonic measurement of abdominal circumference provided limited information on fetal growth. The contribution of a placebo effect to the results of patients receiving more personalised care cannot be discounted.

Adolescent↗
PubMed1981

Fetal electroencephalography using a new, flexible electrode.

A single flexible active electrode for monitoring the fetal electroencephalogram (FEEG), has been designed specifically for use in routine obstetrics. It does not require penetration of or adherence to the fetal scalp, and it is reusable. The equipment's performance has been tested in 20 normal labours. The recordings obtained were not contaminated by the fetal electrocardiogram and were relatively free from artefact so that minimal filtering of the signal was required. No FEEG signal was obtained if the electrode was applied to breech presentations. The trace obtained from a healthy fetus was comparable with that recorded after delivery.

Electrodes↗
PubMed1981

Computer-assisted analysis of chromosomes of the European crested newt.

A computer programme has been developed for partly automating the process of chromosome analysis of the European crested newt (Triturus cristatus carnifex). Chromosome classifications made by the computer and by the cytologist have been compared for a sample of 130 spermatogonial metaphase. The twelve pairs of chromosomes have been classified into three groups. The overall error rate achieved by the computer was 14% for chromosome assignment to single pairs, and 3.8% for chromosome assignment to the proper group.

Animals↗
PubMed1980

Testing of the fungicide maneb for carcinogenicity in two populations of the European crested newt.

The carcinogenic effects of the fungicide manganese ethylenebisdithiocarbamate (maneb) have been investigated in 2 populations of adult crested newt, which have different prevalences of spontaneous melanoma. Animals were exposed percutaneously to a 5 ppm solution of maneb 4 days a week for 37 weeks. No differences in tumor incidence were found between control and maneb-treated animals of either population. Most of the control and treated animals from Settala (Milan) died within 7 months because of the development of widely disseminated melanomas. Tumor incidence was 94% in controls and 98% in maneb-treated newts. In the population from Bagnaia (Perugia) the incidences of melanoma were 7% and 2%, respectively.

Animals↗
PubMed1978

The toxicity of manganese ethylenebisdithiocarbamate to the adult newt, Triturus cristatus.

The toxicity of ethylenebisdithiocarbamate (maneb), a widely used agricultural fungicide, to the adult newt (Triturus cristatus carnifex) was evaluated after percutaneous exposure. Maneb was lethal to all the animals at the 50 ppm level within fifteen days. Male newts seem to be less resistant to the toxicant than females. At concentrations as low as 25 ppm all males died within 25 days, whereas some of the females were still alive after 5 months. Microscopic examination showed that the skin and the kidney were the most severely affected organs. It has been hypothesized that an osmoregulatory breakdown and an impairment of cutaneous respiratory exchanges play a role in the death of the animals. Renal failure must also be taken into account. However, additional mechanisms can not be ruled out at present.

Animals↗
PubMedDate not supplied

Evolutive behavior towards cardiomyopathy of treated (nifurtimox or benznidazole) and untreated chronic chagasic patients.

The aim of this work was to compare the evolution of chronic chagasic untreated patients (UTPs) with that of benznidazole or nifurtimox-treated patients (TPs). A longitudinal study from a low endemic area (Santa Fe city, Argentina) was performed during an average period of 14 years. Serological and parasitological analyses with clinical exams, ECG and X-chest ray were carried out. At the onset, 19/198 infected patients showed chagasic cardiomyopathy (CrChM) while 179 were asymptomatic. In this latter group the frequency of CrChM during the follow-up was lower in TPs compared with UTPs (3.2% vs 7%). Within the CrChM group, 2/5 TPs showed aggravated myopathy whereas this happened in 9/14 UTPs. Comparing the clinical evolution of all patients, 5.9% of TPs and 13% of UTPs had unfavourable evolution, but the difference is not statistically relevant. Serological titers were assessed by IIF. Titers equal to or lower than 1/64 were obtained in 86% of the TPs, but only in 38% of UTPs. The differences were statistically significant (geometric mean: 49.36 vs. 98.2). Antiparasitic assessment of the drugs (xenodiagnosis) proved to be effective. The low sensitivity in chronic chagasic patients must be born in mind. Despite treated patients showed a better clinical evolution and lower antibody levels than untreated ones, it is necessary to carry on doing research in order to improve therapeutic guidelines, according to the risk/benefit equation and based on scientific and ethical principles.

Adolescent↗
PubMedDate not supplied

[Effect of a synthetic somatostatin analogue with delayed action (SMS 201-995) on the biliary expenditure in a patient with an external biliary tract fistula].

The effect of treatment with a long acting analogue of somatostatin (SMS 201-995) administered by subcutaneous route 165 micrograms every eight hours in a patient with a external biliary fistula is reported. There was a significant reduction of the daily fistula output during treatment when compared with the basal periods (p = 0.04), with an average decrease of 270 ml/day during the first period of treatment and 357 ml/day when the drug was administered the second time (p = 0.04). There where not changes in the chemical composition of the bile neither adverse side effects were observed during treatment. These results suggest that SMS 201-995 might be useful in the treatment of external biliary fistulas.

Adult↗