A new method for diatom detection is described. It includes an ultrasonic irradiation procedure with the use of a tissue solubilizer. The method is easy to carry out and is less time-consuming than previous techniques.

Aged↗

PubMedDate not supplied

Effects of prenatal alcohol exposure in mice: influence of an ADH inhibitor and a chronic inhalation study.

In order to examine the effects of an alcohol dehydrogenase inhibitor on the embryotoxic effects of ethanol, pregnant ICR mice were treated with 100 mg/kg pyrazole prior to ethanol injection. I.p. treatment with 2 or 4 g/kg ethanol on day 7 of gestation increased the prenatal mortality rate and produced external and skeletal malformations in the offspring, and the embryotoxic effects were potentiated by pyrazole pretreatment, suggesting that ethanol rather than its metabolites is mainly responsible for the embryotoxicity. In the second experiment, we housed pregnant mice in an ethanol-vapor box for 3 or 6 days in order to examine the effects of prolonged low level exposure to alcohol. The maternal blood alcohol concentration was maintained approximately 0.03 mg/mL during inhalation. The inhalation treatment with ethanol increased the prenatal mortality rate, although teratogenicity was not shown.

Abnormalities, Drug-Induced↗

PubMedDate not supplied

Effects of postnatal exposure to cocaine on the development of the rat corpus callosum.

We investigated the effects of cocaine on the development of the corpus callosum in rats. From postnatal days 1 (P1) to 10 (birth = P0), cocaine (10 mg/kg) was subcutaneously injected in the pups, and saline, at the same volume, was administered to control pups. The animals were sacrificed at 110 days of age and a midsagittal section of the callosum was obtained. Morphometric measurement of the corpus callosum was performed in this section. In the control group, but not in the cocaine group, males had larger callosa than females. The cocaine treatment significantly decreased the total callosal area in male rats. These findings indicate that early postnatal cocaine abolishes the sexual differentiation of the corpus callosum.

Analysis of Variance↗

PubMedDate not supplied

Development of neurons and synapses in ochratoxin A-induced microcephalic mice: a quantitative assessment of somatosensory cortex.

Ochratoxin A (a mycotoxin) is known to cause cell death in the developing brain of embryos 1-2 days after treatment. Microcephaly was observed with high frequency in mice by prenatal treatment with ochratoxin A. Using a stereological method, the numerical densities of neurons and synapses were investigated in the somatosensory cortex of 6-week-old microcephalic mice. The numerical density of neurons in ochratoxin A-treated mice represented a 39% increase compared to the control mice, but there was no difference in the numerical density of synapses. The somatosensory cortices of control mice had about 13,000 synapses per neuron, whereas ochratoxin A-treated mice had about 9,400 synapses per neuron. The deficits in synapse-to-neuron ratios seen in ochratoxin A-induced microcephalic brain seemed to result from a reduced dendritic growth.

Animals↗

PubMedDate not supplied

Comparison of age-associated changes of c-myc gene methylation in liver between man and mouse.

Age-associated changes in DNA methylation of the c-myc gene in liver were compared between humans and mice which have large differences in aging rate. Although the overall methylation profiles of the gene and their age-related changes were found to be similar, the rate of change was much slower in humans than in mice. It suggests that the age-associated alteration of c-myc gene methylation is closely related to biological aging rather than to chronological aging.

Aging↗

PubMedDate not supplied

Effects of amphetamine on rat embryos developing in vitro.

Wistar rat embryos were explanted on Day 10.5 of gestation and exposed in vitro to amphetamine (AMP) at concentrations of 0.1, 0.4, 0.8, 1.2, or 1.6 mM for 24 h, and the direct dysmorphogenic effects of the drug on the embryos were examined by comparisons with a control group. The viability of the cultured embryos was not affected by the AMP treatment. The yolk sac diameter was reduced at AMP concentrations of 1.2 and 1.6 mM. The crown-rump length, the somite number, and the protein content of the embryos were decreased significantly at these two doses, as was the developmental score. The frequency of malformed embryos was increased significantly at the two highest concentrations. The malformations induced in treated embryos included microcephaly, neural tube defects, incomplete rotation of the body axis, and tortuous spinal cord. Abnormal histologic changes, such as derangement and necrosis of the neuroepithelial tissue, were observed in the embryos exposed to the two highest concentrations of the drug. The observed embryotoxic effects appeared to depend on the AMP concentration. Our results demonstrated the direct embryotoxic effects of AMP on rats. The direct dysmorphogenic effect of AMP might be weaker than that of methamphetamine.

Abnormalities, Drug-Induced↗