Effect of (+)-dehydrofukinone on GABAA receptors and stress response in fish model

(+)-Dehydrofukinone (DHF) is a major component of the essential oil of Nectandra grandiflora (Lauraceae), and exerts a depressant effect on the central nervous system of fish. However, the neuronal mechanism underlying DHF action remains unknown. This study aimed to investigate the action of DHF on GABAA receptors using a silver catfish (Rhamdia quelen) model. Additionally, we investigated the effect of DHF exposure on stress-induced cortisol modulation. Chemical identification was performed using gas chromatography-mass spectrometry and purity was evaluated using gas chromatography with a flame ionization detector. To an aquarium, we applied between 2.5 and 50 mg/L DHF diluted in ethanol, in combination with 42.7 mg/L diazepam. DHF within the range of 10-20 mg/L acted collaboratively in combination with diazepam, but the sedative action of DHF was reversed by 3 mg/L flumazenil. Additionally, fish exposed for 24 h to 2.5-20 mg/L DHF showed no side effects and there was sustained sedation during the first 12 h of drug exposure with 10-20 mg/L DHF. DHF pretreatment did not increase plasma cortisol levels in fish subjected to a stress protocol. Moreover, the stress-induced cortisol peak was absent following pretreatment with 20 mg/L DHF. DHF proved to be a relatively safe sedative or anesthetic, which interacts with GABAergic and cortisol pathways in fish.

Sedative and anesthetic activities of the essential oils of Hyptis mutabilis (Rich.) Briq. and their isolated components in silver catfish (Rhamdia quelen)

This study evaluated the sedative and anesthetic effects of the essential oils (EO) of Hyptis mutabilis (Rich.) Briq. and their isolated components on silver catfish (Rhamdia quelen). Quantitative chemical differences between the EOs obtained from leaves and inflorescences were verified, and a new chemotype rich in globulol was described. Although there were no significant differences in the time of induction for sedation and anesthesia between the EOs, only the leaf EO at 344 mg/L anesthetized all fish without side effects. Fractionation of the leaf EO was carried out by column chromatography. The isolated compounds [(+)-1-terpinen-4-ol and (-)-globulol] showed different activity from that detected for the leaf EO in proportional concentrations and similar sedation to a eugenol control at 10 mg/L. However, fish exposed to 1-terpinen-4-ol (3 and 10 mg/L) did not remain sedated for 30 min. Anesthesia was obtained with 83-190 mg/L globulol, but animals showed loss of mucus during induction and mortality at these concentrations. Synergism of the depressor effects was detected with the association of globulol and benzodiazepine (BDZ), compared with either drug alone. Fish exposed to BDZ or globulol+BDZ association showed faster recovery from anesthesia in water containing flumazenil, but the same did not occur with globulol. In conclusion, the use of globulol in aquaculture procedures should be considered only at sedative concentrations of 10 and 20 mg/L, and its mechanism of action seems not to involve the GABAA-BDZ system.

Participation of the GABAergic system in the anesthetic effect of Lippia alba (Mill.) N.E. Brown essential oil

The objective of this study was to identify the possible involvement of the GABAergic system in the anesthetic effect of Lippia alba essential oil (EO). We propose a new animal model using silver catfish (Rhamdia quelen) exposed to an anesthetic bath to study the mechanism of action of EO. To observe the induction and potentiation of the anesthetic effect of EO, juvenile silver catfish (9.30 ± 1.85 g; 10.15 ± 0.95 cm; N = 6) were exposed to various concentrations of L. alba EO in the presence or absence of diazepam [an agonist of high-affinity binding sites for benzodiazepinic (BDZ) sites coupled to the GABA A receptor complex]. In another experiment, fish (N = 6) were initially anesthetized with the EO and then transferred to an anesthetic-free aquarium containing flumazenil (a selective antagonist of binding sites for BDZ coupled to the GABA A receptor complex) or water to assess recovery time from the anesthesia. In this case, flumazenil was used to observe the involvement of the GABA-BDZ receptor in the EO mechanism of action. The results showed that diazepam potentiates the anesthetic effect of EO at all concentrations tested. Fish exposed to diazepam and EO showed faster recovery from anesthesia when flumazenil was added to the recovery bath (12.0 ± 0.3 and 7.2 ± 0.7, respectively) than those exposed to water (9.2 ± 0.2 and 3.5 ± 0.3, respectively). In conclusion, the results demonstrated the involvement of the GABAergic system in the anesthetic effect of L. alba EO on silver catfish.

Prevalence of Mycobacterium avium and Mycobacterium tuberculosis in blood cultures of Brazilian AIDS patients after introduction of highly active retroviral therapy

The use of highly active antiretroviral therapy (HAART) for the treatment of HIV infection has been associated with a marked reduction in the incidence of most opportunistic infections. From April 2001 to February 2002, 80 blood samples from patients who were suspected to have disseminated mycobacterial infection, presenting fever and (preferably) a CD4 T cell count < 100.0 cell/mL were investigated. Twelve (15 percent) of the 80 blood cultures were positive for mycobacteria, with Mycobacterium avium being identified in 7 (8.8 percent) samples and M. tuberculosis in 5 (6.2 percent). The TCD4+ count at the time of M. avium bacteremia ranged from 7cells/æL (average of 48.5 cell/æL), while in M. tuberculosis bacteremia it ranged from 50.0 cells/æL (average of 80.0 cell/æL). The prevalence of M. avium bacteremia in our study follows the expected decline in opportunistic infections observed after the introduction of HAART; however, mycobacteremia by M. tuberculosis still indicates a high prevalence of tuberculosis infection in AIDS patients.

Síndrome serotoninérgico: a propósito de dos casos clínicos reportados al Centro Nacional de Farmacovigilancia / Serotoninergic syndrome: two cases reported to the National Center of Pharmacovigilance (Centro Nacional de Farmacovigilancia)

Se presentan dos casos clínicos de interacción medicamentosa por psicofármacos utilizados para el tratamiento de la ansiedad y de los cuadros depresivos que fueron reportados al Centro de Farmacovigilancia. La presentación clínica se manifestó por alteraciones del nivel de vigilia, síntomas neurovegetativos y síntomas neuromusculares. El cuadro retrocedió con la supresión del fármaco que desencadenó estos síntomaas y con el tratamiento sintomático. Estas manifestaciones clínicas pueden ser atribuídas a una entidad conocida como síndrome serotoninérgico. El diagnóstico del mismo requiere que el fármaco involucrado actúe a nivel de las terminales serotoninérgicas y que se excluyan otros diagnósticos diferenciales más frecuentes. Se discute la etiología del cuadro, sus factores desencadenantes y la terapéutica disponible.

Effect of Plantago australis leaves on different gastric ulcer models

The anti-ulcerogenic effect of the crude ethanolic extract (CEE) of Plantago australis leaves was tested against ethanol-, indomethacin-, and cold restrain-induced stress ulcers. The CEE (500 and 1000 mg/kg) reduced the lesion index (LI) and the ulcer index in ethanol-induced ulcers, and the dose of 1000 mg/kg increased the amount of mucous. The highest dose of the CEE reduced the LI of cold restraint-induced stress ulcers when compared to the control group. The indomethacin-induced ulcers were not affected by this extract.

Pesquisa dos vírus herpes simples I e II (HSV-1 e HSV-2) por PCR / Detection of herpes simplex virus type 1 and 2 by PCR

A maioria das infecções pelos vírus do herpes simples HSV-1 e -2 são silenciosas ou subclínicas. Porém, podem causar doenças bastante graves, tais como meningite e encefalite. A reação em Cadeia pela Polimerase do tipo nested (Nested PCR) permite a detecção precoce e direta do HSV-DNA, com uma sensibilidade superior 95 por cento, fundamental para confirmação rápida e segunda hipótese diagnóstica e, consequentemente, o início do tratamento específico. Foram estudadas amostras de líquor de 19 pacientes com quadro sugestivo de meningite ou encefalite, utilizando técnica de Nested PCR. Cada amostra foi submetida à amplificação de seqüências dos genes das glicoproteínas D e G, presente nos genomas do HSV-1 e -2, respectivamnete. Apenas nas amostras infectadas foi possível observar os produtos de amplificação, uma vez que somente estas continham DNA de HSV-1 e -2. Das dezenove amostras analisadas, dez foram positivas para HSV-1, duas foram positivas para HSV-2 e sete foram negativas para estes dois vírus. O diagnóstico da infecção pelo vírus HSV-1 e -2, por Nested PCR, é viável, preciso, rápido e específico.