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The objective of this study was to investigate both acute and chronic effects of clofibrate and c... more The objective of this study was to investigate both acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and catalase (CAT) of the mosquitofish (Gambusia holbrooki). AChE, commonly used as a biomarker of neurotoxicity, was determined in the total head. LDH, an important enzyme of anaerobic metabolism, was quantified in dorsal muscle, and CAT, enzyme which has been used as indicative parameter of peroxisome proliferation, was determined in the liver. Furthermore, alterations of body and liver weight were also determined, through the calculation of the ratios final body weight/initial body weight, liver weight/final body weight, liver weight/gills weight and liver weight/head weight. Acute exposure of G. holbrooki to both clofibrate and clofibric acid induced a decrease in liver CAT activity, an increase in muscle LDH activity, while no effects were observed on AChE activity. However, chronic exposure did not alter significantly the enzymatic activities, suggesting reduced or null effects over these pathways, relative to effects reported in other species. No effects were observed for the calculated ratios, except a significant weight reduction for males chronically exposed to clofibrate.
The gilthead sea bream (Sparus aurata) is the most important marine cultured species in the Medit... more The gilthead sea bream (Sparus aurata) is the most important marine cultured species in the Mediterranean. Dichlorvos is one of the main chemical agents used in bath treatments against ectoparasites of marine farmed fish. The main objective of this study was to investigate the effects of 24 h dichlorvos baths on selected biomarkers that are involved in important physiological functions or indicative of gilthead sea bream fingerlings growth. To attain this objective, the in vivo effects of dichlorvos on cholinesterases' activity (ChE), lipid peroxidation (TBARS), RNA/DNA ratio, glutathione S-transferases activity (GST) and heat shock proteins HSP70 were studied. The characterization of ChE in brain and muscle was previously determined to select the most sensitive tissue in this species. The exposure of gilthead sea bream fingerlings to dichlorvos caused an inhibition of ChE activity, an increase in lipid peroxidation (TBARS) and a decrease in the RNA/DNA ratio. In contrast, no significant changes in GST and HSP70 were found. The results indicate that ChE, TBARS and RNA/DNA ratio seem to be sensitive biomarkers to detect sub−lethal effects of dichlorvos aquaculture treatments in gilthead sea bream fingerlings.
Journal of Medical Microbiology, 2004
The first investigation of Neisseria meningitidis isolated from a large area covering an apprecia... more The first investigation of Neisseria meningitidis isolated from a large area covering an appreciable population in Portugal, before the voluntary vaccination period with the serogroup C conjugate vaccine, is reported. The serogroups and antimicrobial susceptibility of 116 isolates were studied. Serogroups C (50 . 0 %), B (47 . 4 %) and W135 (2 . 6 %) were found. Serogroup C was most common in the 1-15-years-old group and B in the less than 1-year-old and over 16-years-old groups (P ¼ 0 . 042). Clinical diagnosis of meningococcal disease was primarily meningitis for patients with serogroup C and meningitis associated with sepsis for those with serogroup B. Penicillin resistance was significantly associated with serogroup C (P , 0 . 001). This work reinforces the importance for public health of monitoring the serogroup and antimicrobial susceptibility of isolates from patients with invasive meningococcal disease.
The objective of this study was to investigate both acute and chronic effects of clofibrate and c... more The objective of this study was to investigate both acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and catalase (CAT) of the mosquitofish (Gambusia holbrooki). AChE, commonly used as a biomarker of neurotoxicity, was determined in the total head. LDH, an important enzyme of anaerobic metabolism, was quantified in dorsal muscle, and CAT, enzyme which has been used as indicative parameter of peroxisome proliferation, was determined in the liver. Furthermore, alterations of body and liver weight were also determined, through the calculation of the ratios final body weight/initial body weight, liver weight/final body weight, liver weight/gills weight and liver weight/head weight. Acute exposure of G. holbrooki to both clofibrate and clofibric acid induced a decrease in liver CAT activity, an increase in muscle LDH activity, while no effects were observed on AChE activity. However, chronic exposure did not alter significantly the enzymatic activities, suggesting reduced or null effects over these pathways, relative to effects reported in other species. No effects were observed for the calculated ratios, except a significant weight reduction for males chronically exposed to clofibrate.
The gilthead sea bream (Sparus aurata) is the most important marine cultured species in the Medit... more The gilthead sea bream (Sparus aurata) is the most important marine cultured species in the Mediterranean. Dichlorvos is one of the main chemical agents used in bath treatments against ectoparasites of marine farmed fish. The main objective of this study was to investigate the effects of 24 h dichlorvos baths on selected biomarkers that are involved in important physiological functions or indicative of gilthead sea bream fingerlings growth. To attain this objective, the in vivo effects of dichlorvos on cholinesterases' activity (ChE), lipid peroxidation (TBARS), RNA/DNA ratio, glutathione S-transferases activity (GST) and heat shock proteins HSP70 were studied. The characterization of ChE in brain and muscle was previously determined to select the most sensitive tissue in this species. The exposure of gilthead sea bream fingerlings to dichlorvos caused an inhibition of ChE activity, an increase in lipid peroxidation (TBARS) and a decrease in the RNA/DNA ratio. In contrast, no significant changes in GST and HSP70 were found. The results indicate that ChE, TBARS and RNA/DNA ratio seem to be sensitive biomarkers to detect sub−lethal effects of dichlorvos aquaculture treatments in gilthead sea bream fingerlings.
Journal of Medical Microbiology, 2004
The first investigation of Neisseria meningitidis isolated from a large area covering an apprecia... more The first investigation of Neisseria meningitidis isolated from a large area covering an appreciable population in Portugal, before the voluntary vaccination period with the serogroup C conjugate vaccine, is reported. The serogroups and antimicrobial susceptibility of 116 isolates were studied. Serogroups C (50 . 0 %), B (47 . 4 %) and W135 (2 . 6 %) were found. Serogroup C was most common in the 1-15-years-old group and B in the less than 1-year-old and over 16-years-old groups (P ¼ 0 . 042). Clinical diagnosis of meningococcal disease was primarily meningitis for patients with serogroup C and meningitis associated with sepsis for those with serogroup B. Penicillin resistance was significantly associated with serogroup C (P , 0 . 001). This work reinforces the importance for public health of monitoring the serogroup and antimicrobial susceptibility of isolates from patients with invasive meningococcal disease.