Effects of type II pyrethroid cyhalothrin on rat innate immunity: a flow cytometric study.

Synthetic type II pyrethroids induce anxiety, immunosuppression or, alternatively, immunostimulatory effects in laboratory animals. Macrophages and neutrophils are known to be key elements in cellular immune responses. The present study was designed to investigate the in vivo effects of cyhalothrin (1.0 and 3.0 mg/kg/once daily for 7 days) on macrophage and neutrophil activities, using a flow cytometry method. Results showed that cyhalothrin treatment decreased the percentage and intensity of phagocytosis performed by macrophages, but did not alter these parameters in neutrophils; and also decreased basal neutrophil oxidative burst and increased S. aureus-induced neutrophil oxidative burst, but did not alter these responses in macrophages. The present results are discussed in the light of a possible indirect action of cyhalothrin on macrophage and neutrophil activities via hypothalamic pituitary adrenal (HPA) axis activation. A possible direct effect of cyhalothrin on macrophage and neutrophil activities is also considered.

Cyhalothrin increased c-fos immunoreactivity at the paraventricular nucleus of the hypothalamus in rats, and suppressed macrophage activity in an adrenal-dependent fashion.

Synthetic type II pyrethroid insecticides, such as cyhalothrin at certain dosage levels, simultaneously induce stress-like symptoms and innate immunosuppressive effects in laboratory animals. The present study was designed to further analyze the stress-like effects induced by cyhalotrin and also investigate the role of Hypothalamus-Hypophysis-Adrenal (HHA) axis and Sympathetic Nervous Systems (SNS) and their effects on macrophage activity of rats. Results showed that cyhalothrin treatment (3.0mg/kg/day, for 7 days) increased corticosterone serum levels and c-fos immunoreactivity at the paraventricular nucleus of the hypothalamus (PVN) but induced no changes in c-fos expression at the basolateral amygdala (BLA). Both areas were related to HHA axis and SNS activations by stress. Further analysis showed that adrenalectomy partially abrogated the suppression effects of cyhalothrin on macrophage activity and that 6-OHDA-induced peripheral symphatectyomy had no effects on this innate immune cell activity. The present observed data support and reinforce the notion that cyhalotrin at this treatment schedule induces stress-like symptoms and suggest that other factors, beyond indirect neuroadaptative responses, are necessary for the suppression effects of insecticide on innate immune response.

Cromatografia em camada delgada para o diagnóstico da intoxicação por aldicarb ("chumbinho") em cães e gatos / Thin-layer chromatography for aldicarb poisoning diagnosis in dogs and cats

Avaliou-se a cromatografia em camada delgada (CCD) como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense

The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC) in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology

Dopamine neoinnervation in the substantia nigra and hyperinnervation in the interpeduncular nucleus of adult rat following neonatal cerebroventricular administration of 6-hydroxydopamine.

An aberrant network of dopamine axons was found to pervade the rat substantia nigra following neonatal destruction of its dopamine nerve cell bodies and dendrites by cerebroventricular administration of 6-hydroxydopamine. Light-microscopic immunocytochemistry with a primary monoclonal antibody directed against dopamine-glutaraldehyde-protein was used to investigate the time-course of development and the critical period of induction of this ectopic dopamine innervation (neoinnervation). In rats 6-hydroxydopamine-lesioned at postnatal day 3 (P3) and examined at P7, P10, P15, P30 or later, some dopamine fibers were already present in the substantia nigra at P7; their number increased sharply until P15 and only slightly thereafter, assuming a topographic distribution reminiscent of the missing dopamine nerve cell bodies and dendrites. A similar growth of dopamine fibers took place in the substantia nigra after lesions made at P6, P9 and P12, but was less pronounced after lesion at P15 and absent after lesion at P21 or later. Excessive innervation by dopamine axons (hyperinnervation) was concomitantly observed in the nearby interpeduncular nucleus. The sprouting of dopamine axons in both regions was therefore rapid and coincided in time and space with the developmental redistribution of mesencephalic dopamine neurons in normal rat. It is conceivable that these aberrant dopamine innervations play a role in the peculiar behavior and responsiveness to dopaminergic agents manifested by neonatally 6-hydroxydopamine-lesioned rats. It will be of particular interest to investigate the functional consequences of the dopamine neoinnervation in the substantia nigra, where an eventual axonal release might thus be replacing the normal somatodendritic release of this amine.

[Progressive multifocal leukoencephalopathy mimicking multiple sclerosis as the sole clinical manifestation of acquired immunodeficiency syndrome]. / Leucoencéphalopathie multifocale progressive mimant une sclérose en plaques comme seule expression clinique d'un syndrome d'immuno-déficience acquise.

A 38 year-old wife, of belgian origin and residency, suffered from a left retrobulbar optic neuritis in 1973, with as only sequel dyschromatopsia and central scotoma enlargement. In 1985, 12 years later, she complained of a progressive weakness of the right hand, and developed a spastic tetraplegia within four months. The C.T. Scan showed white matter hypodensities, without mass effect or contrast enhancement, first limited to the left centrum semiovale and later on with multifocal character. Somatosensory evoked potentials after stimulation of the right median nerve demonstrated only lemniscus medialis response. Multiple sclerosis was initially suspected. Analysis of lymphocytes subsets however showed a markedly reduced helper population with as a result a very low H/S ratio, and the serology was found positive for HTLV-III-LAV, thus demonstrating the diagnosis of acquired immune deficiency syndrome (AIDS). Visceral autopsy demonstrated only a CMV pneumonia. Autopsy of the brain showed typical lesions of progressive multifocal leukoencephalopathy (PML). This case is compared with 20 previously published observations of PML associated with AIDS and appears rather unusual due to the association of unfrequent clinical peculiarities: previous, probably coincidental, retrobulbar optic neuritis, female patient, lack of risk factor and clinical symptoms of AIDS. The diagnostic difficulties in the present case are emphasized.

Spinal arachnoiditis due to aspergillus meningitis in a previously healthy patient.

A 30-year-old, previously healthy, non-addicted man presented with a chronic spinal meningitis complicated by arachnoiditis and spinal cord compression. Biopsy showed a chronic granulomatous leptomeningitis, in which some cells contained branching septate organisms that were immunostained with an antiserum to Aspergillus fumigatus. Precipitins to A. fumigatus were detected in cerebrospinal fluid (CSF), but not in blood, and aspergillus infection was apparently restricted to the leptomeninges. Clinically successful treatment led to the disappearance of CSF precipitins and oligoclonal bands.