ABSTRACT
Rats are commonly used in anaphylaxis models, mainly in intestinal anaphylaxis. Hypersensitivity mechanisms are complex and they are not clearly defined. Ovalbumin (OVA) is commonly used for studies on the hypersensitivity mechanism. However, the potential pro-inflammatory mediators induced by this antigen in the model of paw oedema in immunized rats are still not completely understood. This work examines the pharmacological modulation of several mediators involved in rat hind paw immune oedema induced by OVA. Wistar rats were previously immunized (14-18 days) with OVA (30 microg, intraperitoneally) or sham-sensitized with aluminum hydroxide (control). The paw volumes were measured before the antigenic stimuli and 1, 2, 3 and 4 h after the intraplantar injection of OVA (10 microg/paw). Subcutaneous injection of dexamethasone, diphenhydramine, cyproheptadine, chlorpromazine or methysergide significantly inhibited (p < 0.05) the allergic paw oedema. The dual inhibitor of cyclooxygenase and lipoxygenase (NDGA), the cyclooxygenase inhibitor (indomethacin), the lipoxygenase inhibitor (MK-886), the PAF antagonist (WEB 2086), the mast cell stabilizer (ketotifen), and the anti-histamine (meclizine) did not inhibit the immune oedema. In addition, thalidomide and pentoxifylline (anti-tumour necrosis factor drugs) were ineffective against OVA-induced oedema. The fact that indomethacin, MK-886, NDGA and WEB 2086 are unable to inhibit this allergic oedema indicates that the dexamethasone action seems not to be via phospholipase A2, but possibly due to the synthesis and/or the inhibitory activity of cytokines. The paw oedema inhibition by diphenhydramine, but not by meclizine, may suggest a different mechanism, which is independent of the effect of histamine. These data indicate that allergic oedema is more sensitive to anti-serotonin drugs, mainly anti-5-HT2, suggesting that the principal mediator of this inflammatory response is serotonin.
Subject(s)
Edema/immunology , Hypersensitivity/immunology , Ovalbumin/immunology , Animals , Anti-Allergic Agents/pharmacology , Azepines/pharmacology , Chlorpromazine/pharmacology , Dopamine Antagonists/pharmacology , Dose-Response Relationship, Immunologic , Enzyme Inhibitors/pharmacology , Foot , Histamine H1 Antagonists/pharmacology , Immunization , Immunosuppressive Agents/pharmacology , Ketotifen/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Rats , Rats, Wistar , Triazoles/pharmacologyABSTRACT
Foram notificados à Secretaria de Saúde do Estado do Ceará, no período de 1992 a 1995, 688 acidentes causados por serpentes peçonhentas (média anual de 172 casos), com coeficiente de incidência variando entre 0,9 e 5,8 por 100.000 habitantes. Dentre 473 casos em que houve referência ao gênero da serpente 88,3% foram por Bothrops, 10,6% por Crotalus, 0,8% por Micrurus e 0,2% por Lachesis. Os meses de abril a setembro apresentaram maior incidência. Houve predominância de pacientes do sexo masculino (75,6%) e com idades entre 10 a 49 anos (72,3%). As regiões anatômicas mais freqüentemente picadas foram os membros inferiores (81,9%) e superiores (14,7%). O atendimento na unidade de saúde que notificou o acidente ocorreu dentro de seis horas em 66,9% dos casos. A letalidade foi de 0,7%. Os acidentados foram sobretudo agricultores (62,7%), a maioria dos casos ocorreu no próprio local de trabalho. Os autores reforçam que os acidentes ofídicos no Estado do Ceará podem ser considerados acidentes de trabalho, acometem principalmente os trabalhadores rurais e constituem causa de óbito.
From 1992 to 1995, 688 accidents by venomous snakes (mean of 192 cases/year) have been notified to the Health Ministry of the State of Ceará, with an incidence between 0.9 and 5.8/100.000 inhabitants. Among 473 cases, 88.3% were of the genus. Bothrops, 10.7% Crotalus, 0.8% Micrurus and 0.2% Lachesis. The highest incidence occurred from April to September. Male (75.6%) predominated with ages from 10 to 49 years old (72.3%). The more frequently bitten anatomical region were the lower limbs (81.9%) and upper limbs (14.7%). The attendance at health unit which notified the accident took place within 6 hours in 66.9% of the cases. Lethality was 0.7%. The afflicted people were mainly peasants (62.7%), and most of the accidents took place in their own work place. The authors emphasize that the snake bites in the state of Ceará may be considered work accidents, concern mainly peasants and constitute a cause of death.
Subject(s)
Adolescent , Adult , Animals , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Snake Bites/epidemiology , Age Distribution , Brazil/epidemiology , Incidence , Rural Population/statistics & numerical data , Urban Population/statistics & numerical data , Seasons , Sex DistributionABSTRACT
From 1992 to 1995, 688 accidents by venomous snakes (mean of 192 cases/year) have been notified to the Health Ministry of the State of Ceará, with an incidence between 0.9 and 5.8/100.000 inhabitants. Among 473 cases, 88.3% were of the genus. Bothrops, 10.7% Crotalus, 0.8% Micrurus and 0.2% Lachesis. The highest incidence occurred from April to September. Male (75.6%) predominated with ages from 10 to 49 years old (72.3%). The more frequently bitten anatomical region were the lower limbs (81.9%) and upper limbs (14.7%). The attendance at health unit which notified the accident took place within 6 hours in 66.9% of the cases. Lethality was 0.7%. The afflicted people were mainly peasants (62.7%), and most of the accidents took place in their own work place. The authors emphasize that the snake bites in the state of Ceará may be considered work accidents, concern mainly peasants and constitute a cause of death.