ABSTRACT
The amount and distribution of the neurosecretory material in the hypothalamo-neurohypophyseal system were investigated in rats sacrificed 24 hours, 3 or 14 days after single intragastric administration of 2,4-D acid or physiological solution. The amount of the neurosecretory material increased in the whole system after 24 hours and then it decreased on the 3rd and on the 14th day after administration of 2,4-D acid.
Subject(s)
2,4-Dichlorophenoxyacetic Acid/toxicity , Hypothalamus/drug effects , Pituitary Gland, Posterior/drug effects , Animals , Hypothalamus/pathology , Male , Neurosecretory Systems/drug effects , Pituitary Gland, Posterior/pathology , Rats , Rats, WistarABSTRACT
In the spinal ganglia of guinea pigs exposed to general vibration of 40 Hz frequency and 1 mm amplitude for 3 hrs daily, gradually increasing morphological lesions were found after 7, 14, 30 and 90 days of the experiment. The animals exposed to vibration for up to 30 days exhibited a decrease in the cell nuclei volume, increase in the occurrence of eccentric and marginal cell nuclei and nucleoli, as well as an increase in the number of multiple nucleoli. After 90 days' exposure, such severe lesions as tigrolise, vacuolar degeneration of the cytoplasm, granular disintegration of the myelin sheaths or proliferation of glial cells were found.
Subject(s)
Ganglia, Spinal/pathology , Neurons/pathology , Vibration/adverse effects , Animals , Cell Nucleus/ultrastructure , Cytoplasm/ultrastructure , Guinea Pigs , Male , Nerve Degeneration , Neurons/ultrastructure , Time FactorsABSTRACT
After 7 or 30 days of exposure to general vibration (frequency: 40 Hz, amplitude: 1 mm) for 3 hours per day, the prosencephalon of guinea pigs exhibited a wide range of morphological changes, including congestion, haemorrhages, the presence of the heterochromic neurons and perivascular spaces as well as diffuse spongiosis. In contrast, after 14 days' exposure to general vibration of the same parameters, diffuse spongiosis of the prosencephalon was found in all the animals under examination. Hypothalamus, cerebral cortex and periventricular gray matter were unaffected by spongiosis in most of the animals. The nerve fibre sheats were unchanged in all cases.
Subject(s)
Hypothalamus/pathology , Telencephalon/pathology , Vibration/adverse effects , Animals , Brain Edema/etiology , Brain Edema/pathology , Cerebral Hemorrhage/etiology , Cerebral Hemorrhage/pathology , Guinea Pigs , MaleABSTRACT
Some disorders of the brain stem and spinal cord microcirculation were observed in male adult guinea pigs exposed to vertical vibration of frequency 40 Hz and amplitude 1 mm for 3 hours daily during 7, 14, 30 days. These changes after 7 days of vibration were seen as congestion with single small haemorrhages and after 14 days as diffuse spongiosis of the brain stem and spinal cord. After 30 days both congestion with haemorrhages and spongiosis were noted but the first predominated.