Simultaneous action of cypermethrin and two environmental pollutant metals, cadmium and lead, on bone marrow cell chromosomes of rats in subchronic administration.

The aim of the present study was to investigate the possible genotoxic effects, exerted by the pyrethroid cypermethrin and by either of the metals cadmium and lead alone or in combination, on bone marrow cell chromosomes in a subchronic experiment. Outbred male Wistar rats were treated per os for 4 weeks in a five-time per week schedule with 5.54, 11.08, or 22.16 mg/kg cypermethrin (1/100, 1/50, 1/25 LD50) alone, or in combination of 1/100 and 1/50 LD50 cypermethrin with 2.0 mg/kg cadmium chloride or 10 mg/kg lead acetate. On the day following the last treatment, the animals were sacrificed and bone marrow from the femur was prepared. Twenty metaphases from 10 animals per group were evaluated. The evaluation comprised the frequency of aberrant cells, the numerical and structural aberrations, and the alterations in relative organ weights. In the dosage used, cypermethrin and cadmium alone caused no significant increase in the chromosomal aberrations, and lead acetate caused an increase of the numerical aberrations only. Combination of cypermethrin and cadmium also failed to induce significant chromosomal effects. The cypermethrin + lead combination, however, induced a significant increase of structural chromosomal aberrations, predominantly of all acentric fragments. This lead to the conclusion that the simultaneous administration of lead and cypermethrin results in an enhanced genotoxic effect.

Neurophysiological markers as early signs of organophosphate neurotoxicity.

The central and peripheral nervous system effects of acute and subchronic exposure to three organic phosphoro-acid esters (dimethoate, dichlorvos, parathion-methyl) were studied. CNS-dependent variables included mean EEG amplitude, mean frequency of the EEG, and the activity (power density) of six component frequency bands. Peripheral nervous system evaluations included determinations of conduction velocity, and both relative and absolute refractory periods. Cholinesterase activity was measured in blood, brain and other organs. The results indicate that acute large doses of these agents produce substantial changes in these measures of CNS and PNS function. In subchronic experiments it was found that a six weeks administration of 1/50 LD50 of the chemicals induced early functional changes in both the central and the peripheral nervous systems. It is recommended that when cholinesterase inhibition is detected in humans, functional evaluations of CNS and PNS should follow.

A noninvasive method for determination of the sex and karyotype of the fetus from the maternal blood.

The noninvasive method presented, using an "air culturing" technique, is capable of enriching for fetal cells in lymphocyte cultures of maternal blood. Through a combination of Y-body fluorescence and chromosomal heteromorphisms in the maternal blood, the fetal cells can be detected and used for the prenatal diagnosis of chromosomal abnormalities and the sex of the fetus in both the first and the second halves of pregnancy.

The preventive effect of prednisolone on the adrenal toxicity of cadmium.

The effects of a single dose of 3.3 mg/kg body weight i.p. or of a single dose of 0.2 mg/kg per os of cadmium and prednisolone on the adrenal weight and the thickness of the adrenal cortex were investigated in female mice. A significant increase was detected in the mean weight of the adrenals and the thickness of the adrenal cortex was significantly higher than the control value on days 1-3 following cadmium treatment. A dramatic decrease was observed in both adrenal weight and adrenal cortex thickness on day 4 following cadmium administration. No significant change occurred in the adrenals when prednisolone was given orally to mice following cadmium administration. This observation indicates a protective action of prednisolone on cadmium-induced adrenal toxicity.

The effect of prednisolone on the foetotoxicity of cadmium in pregnant mice.

The effects of prednisolone was investigated on the foetotoxicity of cadmium. CFLP female mice were given a single i.p. dose of 2.5 mg cadmium (Cd) per kg body weight on day 5 or 9 of gestation. This treatment significantly decreased both the number of live foetuses and foetal weights on day 18 of gestation. Prednisolone (0.1 mg kg-1) given daily from the day of cadmium treatment death, prevented the effects of cadmium on foetal weights in both groups, and on the number of live foetuses when cadmium was given on day 9 of gestation. When Cd was given on day 13 of gestation similar treatment with prednisolone did not influence either litter size or the weights of 1-day-old pups.

Spontaneous lymphoma in an AKR mouse with dominance of 42 chromosomes.

The chromosome content of the lymphoma cells derived from various organ manifestations of an AKR female mouse with spontaneous lymphoma was investigated. It was found that the lymphoma cells were heterogeneous and the dominant subpopulation of the lymphoma cells contained 42 chromosomes. At least 8 subpopulations of the lymphoma were detected at the karyotype analysis, from which the 41XX; +15; 41XX; +18; 42XX; +15, +18 and 44XX; +5, +8, +15, +18 karyotypes were the most frequent aberrations. The frequency of the presence of various subpopulations was different also in the thymus, spleen and lymph nodes. The authors suggest that over the trisomy of chromosomes 15, other trisomies (e.g. gain of chromosome 18) can play a role in the AKR mouse lymphomagenesis.

Comparative chromosome examination of AKR mouse lymphoma after its i.p. transplantation with thymus- or spleen-derived lymphoma cells into hybrid mice.

A spontaneous AKR female mouse lymphoma was transplanted with its thymus cell suspension (10(6) cells i.p.) into AKR female mice. Lymph node cell suspension derived from one of the leukemic mice was injected (10(6) cells i.p.) into AKR females. The lymphoma cells "homing" to the thymus of one of the AKR females were suspended in Parker solution and 5 X 10(6) cells were given i.p. 5 (C3H X AKR) F3 hybrid mice (group 1). The lymphoma cells "homing" to the spleen of the same AKR female were also suspended, and 5 X 10(6) cells were injected i.p. into 5 (C3H X AKR) F3 hybrids (group 2). Chromosomes were prepared from the thymus and the spleen of two mice in both groups. The karyotypes derived from the hybrids of group 1 were compared to that of the group 2. It was found that the lymphoma cells "homing" to the thymus could be characterized by the trisomy of chromosome 15, while the lymphoma cells "homing" to the spleen had primarily the trisomy of chromosome 18. The results indicate that the thymus manifestation of the spontaneous AKR lymphoma is heterogeneous, and it contains at least two major subpopulations of the lymphoma cells.