Sister-chromatid exchanges and chromosomal aberrations in chick embryos after treatment with the fungicide maneb

The genotoxic potential of a commercial formulation of the fungicide maneb (Maneb 80, containing 80% manganese ethylenebisdithiocarbamate as active ingredient) in chick embryos was evaluated, using as genetic end-points the frequency of sister-chromatid exchanges (SCE) and of chromosomal aberrations. Unincubated eggs were dipped in 0, 0.5, 1.5, 4.5, 13.5 or 27 g/l maneb aqueous solutions for 30 sec. Eggs were then incubated for 4 days. Maneb significantly increased SCE values at 13.5 g/l and at 27 g/l (means 1.33 and 1.74) over the control value (mean 0.87). The concentration of 27 g/l, which corresponds to 10.8 times the recommended maximum application level for use in the field, also resulted in a high mortality rate. No clastogenic effects following exposure to maneb were observed.

Toxicity and distribution of 2-methyl-4-chlorophenoxyacetic acid (MCPA) in developing chick embryos

The toxicity of the herbicide Erbitox E30, a commercial formulation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) containing 28% MCPA as sodium-potassium salt and 72% of unknown ingredients, was tested on chick embryos. Sterile aqueous solutions of MCPA were injected into the air chamber at doses of 0, 1.5, 3.0, 6.0, 9.0, or 10.5 mg/egg on day 0 or on day 4 of incubation. The mortality rate for the embryos treated on day 0 of incubation was high in the first 5 days, low from 5-12 days and again increased by 15 days. The 15-day LD50 was 4.4 mg/egg (95% C.I. 3.7-5.3 mg/egg). HPLC analysis of albumen and yolk showed that concentrations of MCPA in the albumen were detectable at 5 min, highest at 7 days and markedly diminished by 14 days of incubation; a significantly lower concentration of MCPA was found in the yolk throughout the incubation period, except at 14 days when the yolk concentration was 4 times higher than the albumen concentration. At 15 days of incubation, MCPA was evenly distributed in the tissues of the embryo. MCPA was more toxic to 4-day embryos; concentrations above 6.0 mg/egg were lethal to all embryos within the first week of incubation. The 15-day LD50 for treatment on day 4 of incubation was 2.8 mg/egg (95% C.I. 2.5-3.2 mg/egg). The liver was affected by treatment with MCPA, being green in treated embryos. However, histological examination revealed few changes in the liver parenchyma.

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.

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.

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.

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.

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.

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.