Potential benefits of melatonin in organ transplantation: a review

Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acid L-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation

Vulnerability to contamination of the Zaachila aquifer, Oaxaca, Mexico

The aquifer of Zaachila was evaluated following conventional methods (DRASTIC, AVI, and GOD). Depth to the water table was established from a set of wells. Accordingly, the groundwater flows from N to S. Hydraulic conductivity ranges between 1.81647E-05 and 1.70411E-04 m/s, while transmissivity varies between 22.01 and 220.85 m2/day. The net mean annual recharge was estimated at 98 mm/year. The aquifer is constituted mainly by sand, gravel and clay. The soil cover is up to 1.5 m thick and is constituted by lime, clay and sandy material. According to GOD, some zones of this aquifer have a medium to high vulnerability. DRASTIC assigns a high vulnerability to large part of the area. The highest values are observed in the southern and middle sections, from Oaxaca city to the south including San Bartolo Coyotepec, as well as Zaachila town and airport. The AVI method assigns to the valley a high to very high vulnerability. A sensitivity analysis suggests that depth to water table is the key factor determining vulnerability, followed by impact to the vadose zone and soil type

Interpretation of gravity profiles across the northern Oaxaca terrane, its boundaries and the Tehuacán Valley, southern Mexico

A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2. © 2014 Elsevier Ltd

Intraguild predation on the whitefly parasitoid eretmocerus eremicus by the generalist predator geocoris punctipes: A behavioral approach

A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2. " 2014 Elsevier Ltd.",,,,,,"10.1016/j.jsames.2014.09.020",,,"http://hdl.handle.net/20.500.12104/42339","http://www.scopus.com/inward/record.url?eid=2-s2.0-84921911977&partnerID=40&md5=19f002b473bbe8dae489966860b562a3",,,,,,,,"Journal of South American Earth Sciences",,"39

SBA-15 pore-width decrease via a one- or a two-step covalent bonding of a Fischer tungsten carbene as measured by N2 sorption

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system associated with demyelination and axonal loss eventually leading to neurodegeneration. MS exhibits many of the hallmarks of an inflammatory autoimmune disorder including breakdown of the blood-brain barrier (BBB). The BBB is a complex organization of cerebral endothelial cells, pericytes and their basal lamina, which are surrounded and supported by astrocytes and perivascular macrophages. In pathological conditions, lymphocytes activated in the periphery infiltrate the central nervous system to trigger a local immune response that ultimately damages myelin and axons. Cytotoxic factors including pro-inflammatory cytokines, proteases, and reactive oxygen and nitrogen species accumulate and may contribute to myelin destruction. Dysregulation of the BBB and transendothelial migration of activated leukocytes are among the earliest cerebrovascular abnormalities seen in MS brains and parallel the release of inflammatory cytokines. In this review we establish the importance of the role of the BBB in MS. Improvements in our understanding of molecular mechanism of BBB functioning in physiological and pathological conditions could lead to improvement in the quality of life of MS patients. " 2015 IMSS.",,,,,,"10.1016/j.arcmed.2014.11.013",,,"http://hdl.handle.net/20.500.12104/44332","http://www.scopus.com/inward/record.url?eid=2-s2.0-84924813906&partnerID=40&md5=66fa0e94db6736385def9edc370a26b

Role of the Blood-Brain Barrier in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system associated with demyelination and axonal loss eventually leading to neurodegeneration. MS exhibits many of the hallmarks of an inflammatory autoimmune disorder including breakdown of the blood-brain barrier (BBB). The BBB is a complex organization of cerebral endothelial cells, pericytes and their basal lamina, which are surrounded and supported by astrocytes and perivascular macrophages. In pathological conditions, lymphocytes activated in the periphery infiltrate the central nervous system to trigger a local immune response that ultimately damages myelin and axons. Cytotoxic factors including pro-inflammatory cytokines, proteases, and reactive oxygen and nitrogen species accumulate and may contribute to myelin destruction. Dysregulation of the BBB and transendothelial migration of activated leukocytes are among the earliest cerebrovascular abnormalities seen in MS brains and parallel the release of inflammatory cytokines. In this review we establish the importance of the role of the BBB in MS. Improvements in our understanding of molecular mechanism of BBB functioning in physiological and pathological conditions could lead to improvement in the quality of life of MS patients. © 2015 IMSS

Dopamine release modifies intracellular calcium levels in tyrosine hydroxylase-transfected C6 cells

Glioma cell line C6, transfected with tyrosine hydroxylase (TH) cDNA under the control of the glial fibrillary acid protein promoter (C6-THA cells), elicited a reduction in the apomorphine-induced turning behavior when they are implanted in Parkinson's disease models. Nevertheless, dopamine (Da) release has not been explicitly demonstrated nor has a possible mechanism of release been implicated. In this study, the in vitro Da release by C6 and C6-THA cells after chemical stimulation with KCl or glutamate was quantified using HPLC. Modifications in intracellular calcium levels in response to KCl stimulation and participation of Da receptor-mediated feedback in calcium regulation were also studied using FLUO 3 as a calcium concentration indicator. C6-THA cells release dopamine in basal conditions, and increase its release after KCl or glutamic acid stimulation. In a fraction of C6 and C6-THA cells, a transient intracellular calcium increase was observed after KCl stimulation, but C6-THA cells demonstrated a faster rate of calcium removal. C6 cells express mRNA from all five subtypes of Da receptors as demonstrated by real time PCR. D1 receptors were most abundant in C6 cells and its expression was further increased in C6-THA cells. Blocking D1-like receptors in C6-THA cells with the specific antagonist drug SCH-23390 induced a decrease in intracellular calcium removal rate, resembling non-manipulated C6 cells' calcium clearance. Da release by C6-THA cells could be related to calcium dependent mechanisms. Furthermore, production of Da by C6-THA cells seems to upregulate the expression of D1 receptors' mRNA. © 2007 Elsevier Inc. All rights reserved

Pesticide toxicity and its association with Parkinson's disease [Toxicidad de plaguicidas y su asociación con la enfermedad de Parkinson]

Epidemiological data in humans and studies in animal models of Parkinson's disease (PD) suggest that sporadic forms of the disorder are not strictly genetic in nature but most likely because of combined environmental exposures over the period of the life-span coupled with increased genetic susceptibilities. Exposure to agricultural chemicals such as paraquat, diquat, maneb, rotenone, and dieldrin has been separately suggested as potential risk factors for sporadic forms of the disease. In addition, exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a by-product of synthetic heroine causes a clinical condition almost identical to PD. Interestingly, paraquat and MPTP share striking structural similarities. There is a growing consensus that oxidative stress and inflammation plays a key role in PD. Using a rodent model we found that melatonin attenuates the increases in lipid peroxidation products, nitric oxide catabolites and ciclooxygenase 2 activity elicited by MPTP injection. These data suggest that neuroprotective effects of melatonine are partly attributed to its antioxidant and anti-inflammatory action. Copyright © Indice Mexicano de Rev istas Biomédicas Latinoamericanas 1998 - 2013

Pesticide toxicity and its association with Parkinson's disease [Toxicidad de plaguicidas y su asociación con la enfermedad de Parkinson]

Epidemiological data in humans and studies in animal models of Parkinson's disease (PD) suggest that sporadic forms of the disorder are not strictly genetic in nature but most likely because of combined environmental exposures over the period of the life-span coupled with increased genetic susceptibilities. Exposure to agricultural chemicals such as paraquat, diquat, maneb, rotenone, and dieldrin has been separately suggested as potential risk factors for sporadic forms of the disease. In addition, exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a by-product of synthetic heroine causes a clinical condition almost identical to PD. Interestingly, paraquat and MPTP share striking structural similarities. There is a growing consensus that oxidative stress and inflammation plays a key role in PD. Using a rodent model we found that melatonin attenuates the increases in lipid peroxidation products, nitric oxide catabolites and ciclooxygenase 2 activity elicited by MPTP injection. These data suggest that neuroprotective effects of melatonine are partly attributed to its antioxidant and anti-inflammatory action. Copyright Indice Mexicano de Rev istas Biomédicas Latinoamericanas 1998 - 2013