Humans ; Infant ; Lead Poisoning, Nervous System, Childhood ; diagnosis ; therapy ; Male

Child, Preschool ; Diagnosis, Differential ; Female ; Humans ; Lead Poisoning, Nervous System, Childhood ; diagnosis ; therapy ; Male

Child, Preschool ; Humans ; Lead Poisoning, Nervous System, Childhood ; complications ; Male ; Optic Neuritis ; etiology

Adult ; Humans ; Lead Poisoning, Nervous System ; etiology ; Male

The neurotoxic effects of inorganic lead, a common environmental toxic substance, include peripheral neuropathy in adults and encephalopathy in children. Behavioral changes including hyperactivity, short attention span, easy distractibility and impulsiveness have also been noted in patients with chronic lead exposure in childhood. The level of norepinephrine in brain may relate to hyperactivity and chronic lead exposure. The purpose of this study was to determine the effect of inorganic lead (PbCl(2)) administration in neonatal rats using immunocytochemical and electron microscopical analysis of norepinephrinergic neurons of the locus ceruleus. Lead chloride were dissolved in distilled water at the concentration of 0.05%, 0.1% and 0.2% and the solution was administered orally via drinking water. After 4, 8 or 12 weeks of continuous administration, all rats were sacrificed and the brain was processed and immunostained with antibody against tyrosine hydroxylase, a rate limiting enzyme of norepinephrine synthesis antibody. The number of tyrosine hydroxylase immunostained cell bodies in locus ceruleus was estimated. Densitometric analysis of tyrosine hydroxylase immunoreactive profiles in electron microscopic photographs were done by using image analyzer. The number of tyrosine hydroxylase immunoreactive neurons in the locus ceruleus had increased statistically after lead administration. Density of tyrosine hydroxylase immunoreactive profiles in the electron microscopy had also increased. Degenerative changes, such as intra-axonal vacuolar space formation, were found within tyrosine hydroxylase immunoreactive axons. Somewhat widened intercellular spaces and retracted processes were also found in the region of the locus ceruleus. Increased tyrosine hydroxylase immunoreactivity may correlate with hyperreactivity of lead intoxicated children. Degenerative changes may be responsible for the short attention span, easy distractibility and impulsiveness observed in case of mild lead poisoning.
Adult ; Animals ; Axons ; Brain ; Child ; Drinking Water ; Extracellular Space ; Humans ; Immunohistochemistry ; Lead Poisoning ; Locus Coeruleus* ; Microscopy, Electron ; Neurons* ; Norepinephrine ; Peripheral Nervous System Diseases ; Rats* ; Tyrosine 3-Monooxygenase ; Water

Lead, which is widely used in industry, is a common element found in low concentrations in the Earth's crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, hematopoietic system, and nervous system. Having a carcinogenic risk as well, the IARC classifies inorganic lead compounds as probably carcinogenic to humans (Group 2A). Occupational lead poisonings have decreased due to the efforts to reduce the lead concentrations in the working environment. In contrast, health hazards associated with long-term environmental exposure to low concentrations of lead have been reported steadily. In particular, chronic exposure to low concentrations of lead has been reported to induce cognitive behavioral disturbances in children. It is almost impossible to remove lead completely from the human body, and it is not easy to treat health hazards due to lead exposure. Therefore, reduction and prevention of lead exposure are very important. We reviewed the toxicity and health hazards, monitoring and evaluation, and management of lead exposure.
Antioxidants ; Child ; Environmental Exposure ; Hematopoietic System ; Human Body ; Humans ; Kidney ; Lead Poisoning ; Liver ; Nervous System

Compound nerve action potential (CNAP) of the mixed peripheral nerve is composed of A alpha beta, A delta, and C potentials. All components of CNAPs in the sciatic nerve were recorded by stimulating the tibial nerve of both control and lead-poisoned rats. Marked decrease of nerve conduction velocity and prolonged duration were found in A alpha beta and A delta fibers especially in large myelinated A alpha beta fibers. The amplitude decreased in A alpha beta potential, but the area did not change. In C potential produced by activation of unmyelinated fibers, nerve conduction velocity slightly decreased, but the amplitude and area did not significantly change. Pathologic correlates revealed prominent segmental demyelination with significant decrease of large myelinated fiber densities. Minimal axonal degeneration of unmyelinated fibers was present. We can conclude that electrophysiologic changes in the lead-poisoned rats correlate with pathologic changes in them.
Animals ; Electrochemistry ; Lead Poisoning/complications/*pathology ; Neural Conduction ; Peripheral Nervous System Diseases/chemically induced/*pathology ; Rats ; Rats, Inbred Strains ; Sciatic Nerve/pathology

OBJECTIVETo study the effects on the expression of mGluR5 mRNA and protein levels in primarily cultured hippocampal neurons after lead exposure.

METHODSPrimary embryonic rat hippocampal neuronal culture was prepared. On the 3(rd) day of incubation, lead chloride solution was added into medium to produce four different lead exposure levels: 0, 1 x 10(-8) mol/L, 1 x 10(-6) mol/L, 1 x 10(-4) mol/L Pb(2+). After 10 days of incubation, the neurons were collected to measure the alteration of mGluR5 mRNA expression by real-time fluorescent quantity PCR and the expression of mGluR5 in protein level by Western blot.

RESULTSThe studies revealed that mGluR5 mRNA expression was down-regulated after lead exposure in a dose-dependent manner. The mGluR5 mRNA expression of the lower lead-exposed neurons (Pb(2+) 10(-8) mol/L), the medium lead-exposed neurons(Pb(2+) 10(-6) mol/L), the higher lead-exposed neurons(Pb(2+) 10(-4) mol/L) were 0.724, 0.421, 0.321 times less than that of the controls, respectively. The Western blot demonstrated that mGluR5 expression in protein level should be decreased after lead exposure.

CONCLUSIONThe expression of mGluR5 in mRNA and protein levels should be down-regulated after lead exposure at different lead levels in a dose-dependent manner.

Animals ; Animals, Newborn ; Cells, Cultured ; Female ; Hippocampus ; drug effects ; metabolism ; Lead ; toxicity ; Lead Poisoning, Nervous System ; metabolism ; Neurons ; drug effects ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptor, Metabotropic Glutamate 5 ; Receptors, Metabotropic Glutamate ; biosynthesis ; genetics