Multiple anthropogenic influences in the Pará River (Amazonia, Brazil): A spatial-temporal ecotoxicological monitoring in abiotic and biotic compartments

The mineral wealth of the Amazon region is prone to intense exploration with consequent metals mobilization in ecosystems. Besides that, a number of other anthropogenic activities contribute to the imbalance of this important environment. The Pará River is an important water body in the Amazon basin and is under multiple anthropogenic influences, including disorderly urbanization, port activities and processing of minerals such as bauxite and kaolin. In this study, metals concentrations (Al, Cr, Pb, Ba, Ni, and Mn) in water, sediment and organisms (the fish Cheirocerus goeldii and the shrimp Macrobrachium amazonicum) and biochemical biomarkers (total antioxidant capacity, ACAP and lipid peroxidation, LPO) were analyzed along five points in the Para River with different distances to a center of anthropogenic activity, in three seasonal periods (rainy, transition and dry). Metals concentrations were similar among sites in each seasonal period but Aluminium (Al) presented the highest concentrations among all analyzed metals both in sediment and water considering all sampling points and all seasonal periods. In the dissolved fraction, Al had values above those established by the local environmental agency, especially during the rainy season. In the biotic compartment, both fish and shrimps showed higher concentrations of metals (Al and Ba) in the rainy season compared to the other seasons. Shrimp was more responsive to metal accumulation than fish, showing an adaptive response of biomarkers. Fish showed an increase of LPO in gills for individuals from the point of greater anthropogenic interference during the rainy season, but no differences in metal accumulation. We conclude that there is a seasonal pattern of metals concentration in different environmental compartments. Metal concentration in organisms and biomarkers responses, showed the effect of anthropogenic influences, which was not evident in results from chemical analyses alone, due to the intensive hydrodynamics in the region.

Distribution of metals in different environmental compartments and oxidative stress biomarkers in Bryconops caudomaculatus (Osteichthyes: Characiformes) from a bauxite mining area in the Eastern Amazon

The Eastern Amazon is rich in bauxite ore. The extraction and processing of bauxite lead to the mobilization of Aluminum (Al) and other metals in environmental. We evaluated the metals (Al, Mn, Ba, and Cr) concentration in tissue, water, and sediment associated with antioxidant and oxidative damage responses in Bryconops caudomaculatus. The samplings were done in two hydrological periods (post-rain and post-dry periods) and at three points, located at two rivers: one in the surroundings of the mining area (P1) and other inside the mining area, upstream (P2), and downstream (P3). Defense antioxidant system biomarkers analyzed were total antioxidant capacity (ACAP) and glutathione-S-transferase (GST) activity. As an oxidative damage biomarker, the lipoperoxidation (LPO) was evaluated. Metals concentrations in the water and sediment were higher in the post-rain period compared to post-dry period. The water samples were acidic, with dissolved Al concentrations above the values established by local legislation at all points. In the gills, the metals accumulation was higher in fish from in the surrounding and upstream sites, and in the liver, was higher in fish from downstream site. Fish from the surrounding had increased antioxidant defenses, with higher ACAP in all tissues and higher GST in the gills. Consequently, they had lower levels of LPO. Fish from the mining area had decreased antioxidant defenses, with lower ACAP in all tissues and lower GST in the gills. Consequently, they had higher levels of LPO, indicating oxidative stress. The fish muscle was not responsive to GST and LPO at all sites. We conclude that the oxidative stress observed in the gills and liver of B. caudomaculatus from the area modified by the mining activity reflected the local anthropogenic impact status.

Amitriptyline converts non-responders into responders to low-frequency electroacupuncture-induced analgesia in rats

AIMS

The purpose of this study was to examine whether the use of intraperitoneal or intrathecal amitriptyline combined with electroacupuncture modifies the tail-flick reflex and incision pain in rats that normally do not have analgesia to electroacupuncture in the tail-flick test (non-responder rats).

MAIN METHODS

Changes in the nociceptive threshold of intraperitoneal or intrathecal saline- or amitriptyline-treated non-responder rats were evaluated using the tail-flick or incision pain tests before, during and after a 20-min period of electroacupuncture, applied at 2 Hz to the Zusanli and Sanynjiao acupoints. Amitriptyline was used at doses of 0.8 mg/kg or 30 μg/kg by intraperitoneal or intrathecal route, respectively. At these doses, amitriptyline has no effect against thermal or incision pain in rats.

KEY FINDINGS

Rats selected as non-responders to the analgesic effect of electroacupuncture 2 Hz in tail-flick and incision pain tests become responders after an intraperitoneal or intrathecal injection of amitriptyline.

SIGNIFICANCE

Amitriptyline converts non-responder rats to rats that respond to electroacupuncture with analgesia in a model of thermal phasic pain and anti-hyperalgesia in a model of incision pain.

Magnetic resonance cholangiopancreatography in cystic lesions of the pancreas

There are few reports about magnetic resonance cholangiopancreatography (MRCP) in cystic lesions of the pancreas (KLP). For this reason, we have undertaken a prospective study evaluating the diagnostic efficiency of MRCP as compared with ultrasonography. Twenty-four patients with KLP were examined with magnetic resonance imaging (MRI), and standard and cholangiopancreatography. There were seven cases of cysts associated with acute pancreatitis, 11 patients with KLP and chronic calcifying pancreatitis, five cases of cystic neoplasms of the pancreas, and one polycystic disease of the gland. All cases were first submitted to ultrasonography, which failed to diagnose only a case of cyst associated with chronic pancreatitis depicted by MRCP. We used a GE Signa Horizon 1.5-T system (20 examinations) and a Siemens Magneton Plus 1.5-T machine (four examinations). Eleven patients were operated on. In all cases, it was possible to identify the cysts, the main pancreatic duct and the biliary tree, and verify the relationship of the cyst with neighboring organs. Communication of the cyst with the main pancreatic duct was described in five instances, but we cannot be sure that MRCP would have depicted all cyst-duct communications. The MRI and MRCP images were confirmed by surgery in the 11 operated-on cases. The diagnosis of duct alterations and small pancreatic stones in initial cases of chronic calcifying pancreatitis may be problematic. Clinical findings are very important data to be considered in the differential diagnosis of KLP. Together with the clinical data, MRCP is a very important technique in the diagnostic and therapeutic decision making of KLP. Standard magnetic resonance is advisable as part of the examination in all cases. MRCP is not invasive, is reliable if one knows its limitations, and the patient can return at once to his activities. It allows the analysis of many variables in one examination, contributing to better therapy.