Biomedical subjects

A Albores-Medina

Publications and source records attributed to A Albores-Medina.

3 recordsLinked to original sources

PubMed1996

Lead exposure in a population of Mexican children.

The effects of low lead exposure were investigated in 96 children (7-12 years old) living and studying within a 1 km radius of a lead smelter (exposed population) located in Torreón, Coahuila, México, and compared with 30 children living and studying 4.5 km from the same smelter (control population). Both populations had similar socio-economic conditions. The exposed population showed higher blood lead (PbB) and free erythrocyte protoporphyrin (FEP) concentrations (17.3 +/- 5.6 micrograms dl-1 and 53.9 +/- 46.1 micrograms dl-1, respectively) than controls (PbB, 5.4 +/- 3.1 micrograms dl-1 and FEP, 13.9 +/- 7.3 micrograms dl-1). PbB concentrations were inversely correlated to distance from the smelter (r2 = 0.494). However, in the exposed population, wind direction also had a significant effect on the PbB and urinary lead (PbU) concentrations. The exposed population was divided according to PbB into a high level lead group (PbB > 15 micrograms dl-1), which also showed high FEP concentrations and a low lead group (PbB < 15 micrograms dl-1). Clinically, the high lead group showed a greater incidence of general symptoms (colic, headache, paresthesia, myalgia and dizziness), impairment of some neuromuscular functions (neuromuscular conduction velocity and motor coordination) and a decrease of intelligence quotient (IQ), which was not related with sex or socio-economic status. These results are an evidence of morbidity in children with high PbB concentrations.

Child↗

PubMed1996

Lead: intestinal absorption and bone mobilization during lactation.

The aim of this study was to examine lead (Pb) intestinal absorption, its mobilization and redistribution during lactation in rats chronically exposed to lead. Lead and calcium (Ca) concentrations were measured in blood, milk, femurs, liver and kidney samples obtained from pregnant and lactating mother rats which were subjected to different schedules of exposure to Pb: 158 days before and during lactation (group A), 144 days before lactation (group B) and 14 days only during lactation (group C). Results were compared to those of non-pregnant but Pb-exposed matched rats and non-exposed control rats. In groups A and B during lactation, Pb in blood (PbB), liver and kidney increased while Pb in bone decreased. Since there was not an external source of Pb in group B during lactation, the results indicate resorption of Pb in bone as the main source of Pb in the organism. In group A, there was an additional increase of PbB when compared to group B as a result of Pb intestinal absorption. In group C a significant increase in PbB due to intestinal absorption and deposit in bone was found when compared to non-pregnant 144 days old rats, suggesting that the three processes intestinal absorption, bone resorption and bone absorption were taking place. These data indicate that Pb stored in bone as a result of prior maternal exposure, should be considered as a major source of self intoxication and of Pb in milk available to suckling pups.

Administration, Oral↗

PubMedDate not supplied

Toxicity of sediments from Bahía de Chetumal, México, as assessed by hepatic EROD induction and histology in nile tilapia Oreochromis niloticus.

The effect of environmental pollutants present in sediments obtained from Bahía de Chetumal, a bay on the border between Mexico and Belize, was studied in nile tilapia (Oreochromis niloticus) intraperitoneally injected with sediment extracts from six different sites of the Bay. Sediment samples used for the study contained a variety of organic chemicals such as organochlorine pesticides, polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs). Total cytochrome P-450 and EROD activity were measured in fish liver. Haematological and histological analyses were also carried out. Hepatic P-450 content in treated fish increased from 43 to 240%, and EROD activity from 85 to 160% compared to controls. Extracts from two sampling sites inhibited EROD activity. There were positive significant correlations between P-450 content and the levels of PCBs 44 and 128. EROD activity correlated to HCB, op'-DDE, pp'-DDE, pp'-DDD, mirex and PCB 18 concentrations. Blood examination showed cell degeneration and binucleated leukocytes with abnormal chromatin. Extract treatment also resulted in foci of hyperplasia on the basement of gill lamellae, hypertrophy and oedema in gills and liver necrosis. Control fish showed no abnormalities. The results demonstrate that sediments from Bahía of Chetumal have the potential to cause histopathological, haematological and biochemical alterations in fish. The administration of sediment extracts to fish may serve as a useful test to screen the toxicity of sediments from different areas.

Animals↗