Long-term and low dose oral malathion exposure causes morphophysiological changes in the colon of rats.

BACKGROUND: Malathion (MAL) is an organophosphate insecticide that inhibits cholinesterases, used to control pests in agriculture and to combat mosquitoes that transmit various arboviruses. As acetylcholine is one of the major neurotransmitters of the enteric nervous system (ENS), humans exposed to MAL by ingestion of contaminated food and water can develop symptoms due disfunction of the gastrointestinal tract. Although the deleterious effects after exposure to high doses are recognized, little is known about the long-term and low-dose effects of this pesticide on the structure and motility of the colon. AIMS: to evaluate the effects of prolonged oral exposure to low levels of MAL on the wall structure and colonic motility parameters of young rats. MAIN METHODS: The animals were divided into three groups: control, and groups that received 10 or 50 mg/kg of MAL via gavage for 40 days. The colon was collected for histological analysis and analysis of the ENS through the evaluation of total neurons and subpopulations of the myenteric and submucosal plexuses. Cholinesterase activity and functional analyzes of the colon were evaluated. KEY FINDINGS: MAL treatments (10 and 50 mg/Kg) reduced the butyrylcholinesterase activity, and caused enlargement of faecal pellets, atrophy of muscle layers and several changes in neurons of both myenteric and submucosal plexi. Considering colonic contraction, MAL (50 mg/Kg) increased the number of retrograde colonic migratory motor complexes. SIGNIFICANCE: The long-term exposure to low doses of MAL affects colonic morphophysiology, which highlights the need to intensify control and care in the use of this pesticide.

[Cryptococcus neoformans var. neoformans isolated from soil]. / Cryptococcus neoformans var. neoformans isolado do solo.

We inquiry, in the epidemiologic history of 42 patients with cryptococcosis, the contact with pigeon, trying to find the possible source of infection. Of these patients, the information compatible with ecologic niche of Cryptococcus neoformans was positive in 16. Fifty nine samples were recovered from soil, associated with pigeon habitat. We found C. neoformans in four occasions, one in the capital and three in the interior of state. C. neoformans, serotype A, recovered from a central spine fluid coincides with the serotype of the fungus recovered downtown Porto Alegre, in a place suggested by the patient as possible source of infection, characterizing of a case of Cryptococcus neoformans. var. neoformans.

[An exploratory analysis of information on inter- and intra-municipal migration in the 1980 census]. / Uma analise exploratoria da informacao sobre a migracao inter e intramunicipal no censo demografico de 1980.

PIP: Levels of inter- and intraurban migration in Brazil are analyzed using data from a 25 percent sample of the 1980 census. Interurban migration is examined by urban size. The authors estimate the number of migrations of unknown origin and the significance of return migration. The importance of age and time of residence data in estimating intraurban migration is noted. Suggestions to improve data collection methods for the 1990 census are made. (SUMMARY IN ENG)^ieng