Publications by authors named "Leon G"

Auriculostoma totonacapanensis n. sp. is described from the Mexican tetra, Astyanax mexicanus (Actinopterygii, Characidae) collected in a tributary creek of the Bobos River in Filipinas, Veracruz, Mexico.

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Nitrophenols are common organic pollutants that enter the environment during the manufacture and processing of a variety of industrial products. The removal of 4-nitrophenol (4NP) from aqueous solutions by emulsion liquid membranes using the type I facilitated transport mechanism is investigated in this paper. The liquid membrane consisted of kerosene as the organic diluent, sorbitan monooleate as the emulsifying agent and sodium hydroxide as the stripping agent.

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The host eIF4F translation initiation complex plays a critical role the translation of capped mRNAs. Although human cytomegalovirus (HCMV) infection increases the abundance and activity of the host eIF4F complex, the requirement for eIF4F components in HCMV replication and mRNA translation has not been directly tested. In this study, we found that decreasing the abundance or activity of eIF4F from the start of infection inhibits HCMV replication.

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Objectives: Few studies have investigated effective masking levels (EMLs) needed to isolate the test ear for bone conduction assessments in infants. The objective of this study was to determine EMLs for 500 and 2000 Hz bone conduction auditory steady state responses (ASSRs) to amplitude (AM)/frequency-modulated (FM) stimuli for infants and adults with normal hearing. Maturational factors that contribute to infant-adult differences in EMLs will also be investigated.

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Vacuolar solute accumulation has been shown to be a mechanism by which plants are capable of increasing drought and salt tolerance. The exposure of plants to NaCl induces H+ transport into the vacuole by specialized pumps. One of them corresponds to the vacuolar H+-pyrophosphatase, which generates a H+ gradient across the vacuolar membrane.

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Snake antivenoms are formulations of immunoglobulins, or immunoglobulin fragments, purified from the plasma of animals immunized with snake venoms. Their therapeutic success lies in their ability to mitigate the progress of toxic effects induced by snake venom components, when administered intravenously. However, due to diverse factors, such as deficient manufacturing practices, physicochemical characteristics of formulations, or inherent properties of heterologous immunoglobulins, antivenoms can induce undesirable adverse reactions.

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The occurrence of parasitic copepods of the family Caligidae on wild and cultured marine fishes from Chamela Bay, on the Pacific coast of Mexico, is reported. A total of 16 species of Caligus and 1 species of Lepeophtheirus were found on 19 wild fish species. The description of Caligus chamelensis n.

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Caligus serratus Shiino, 1965 (Copepoda: Caligidae), a parasite on 11 fish species caught in Chamela Bay off the Pacific Coast of Mexico, is redescribed based on material found on Pacific agujon needlefish Tylosurus pacificus (Steindachner, 1876). Caligus serratus can be distinguished from its congeners by the combination of the following characters: i) short abdomen (approximately 0.2 times as long as cephalothorax), ii) pointed posteromedial process on the first segment of the antenna, iii) sternal furca with bluntly pointed, diverging tines, and iv) leg 4 exopod bearing 3 unequal, distal spines (the shortest 0.

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Objective: The objective of this study was to investigate predictor variables at the moment of normal stress-rest myocardial perfusion gated SPECT for indication of a second gated SPECT.

Material And Methods: A prospective, single center cohort study was conducted. We evaluated 2326 consecutive patients (age 63.

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Therapeutic communities (TC s) have a strong record of maintaining a high quality social climate on prison units. One possible reason for this is the system of mutual monitoring among TC residents, based on the assumption that peer affirmation of behavior in accord with TC norms and peer correction of behavior contrary to TC norms will lead to increased resident prosocial behavior. Laboratory experiments have demonstrated that such peer monitoring can lead to cooperation, but there has been no quantitative test of this hypothesis in an actual TC.

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Background: Decisions regarding health systems are sometimes made without the input of timely and reliable evidence, leading to less than optimal health outcomes. Healthcare organizations can implement tools and infrastructures to support the use of research evidence to inform decision-making.

Objectives: The purpose of this study was to profile the supports and instruments (i.

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Genetic analyses of hosts and their parasites are key to understand the evolutionary patterns and processes that have shaped host-parasite associations. We evaluated the genetic structure of the digenean Crassicutis cichlasomae and its most common host, the Mayan cichlid "Cichlasoma" urophthalmus, encompassing most of their geographical range in Middle-America (river basins in southeastern Mexico, Belize, and Guatemala together with the Yucatan Peninsula). Genetic diversity and structure analyses were done based on 167 cytochrome c oxidase subunit 1 sequences (330 bp) for C.

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The helminth parasite fauna of the hylid frog Pseudacris hypochondriaca in several localities along the Baja California Peninsula in northwestern Mexico is presented. The helminth fauna consists of 4 species of nematodes (Oswaldocruzia pipiens, a larval form of an Ascaridid, 2 new species belonging to the genera Rhabdias and Cosmocercoides), and 1 species of digenean ( Gorgoderina sp.).

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Purpose: To estimate at-risk and salvaged myocardium by using gated single photon emission computed tomography (SPECT) myocardial perfusion imaging after acute myocardial infarction (AMI).

Materials And Methods: The study was approved by the hospital's Ethical Committee on Clinical Trials (trial register number, PR(HG)36/2000), and all patients gave informed consent. Forty patients (mean age, 61.

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Background: The incremental prognostic value of myocardial perfusion-gated single photon emission computed tomography (MPGS) compared with exercise test has not yet been properly evaluated.

Methods And Results: Five thousand six hundred seventy-two consecutive patients with known or suspected coronary disease undergoing exercise MPGS between 1997 and 2007 were included. Three-year predictive models for total death and death from cardiovascular causes or acute myocardial infarction (ie, major cardiovascular events [MCE]) were built using Cox-regression modeling, including only the clinical information.

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Introduction: Social and political instability have become common situations in many parts of the world. Exposure to different types of traumatic circumstances may differentially affect psychological status.

Objective: The aim of this study was to compare the relationship between personal perceptions of control over the events happening in one's life and psychological distress in two groups who experienced physical trauma but differed as to whether the trauma was a result of political upheaval and violence.

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The taxonomic history and species composition of the genus Clinostomum has been unstable. Two species, Clinostomum complanatum Rudolphi, 1814 and Clinostomum marginatum Rudolphi, 1819, have been particularly problematic and its validity has been disputed for nearly 200 years. In this paper, we have made use of an integrative taxonomy approach, and we used, in first instance, DNA sequences of two genes (cox1 and ITS) to test the validity of C.

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Background: The objective of this study was to investigate the impact of clinical, electrocardiographic and stress testing variables in predicting hard cardiac events (HE) and coronary revascularization (CR) in patients with normal stress-rest gated SPECT.

Materials And Methods: Included in the study were 2,004 patients (63.5 ± 12.

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Antivenom pharmacokinetics has been studied in heterologous models in which the animal species used as immunoglobulin source is different from that used as recipient. In these models, after intravenous administration of antivenom, the plasma concentration of immunoglobulins shows a rapid initial declining-phase followed by a slower terminal-phase, which has been associated with antivenom distribution and elimination, respectively. We have compared pharmacokinetic parameters for equine-derived antivenom in homologous (horse) and heterologous (cow) models.

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Background: Evidence-informed health policymaking logically depends on timely access to research evidence. To our knowledge, despite the substantial political and societal pressure to enhance the use of the best available research evidence in public health policy and program decision making, there is no study addressing availability of peer-reviewed research in Canadian health ministries.

Objectives: To assess availability of (1) a purposive sample of high-ranking scientific journals, (2) bibliographic databases, and (3) health library services in the fourteen Canadian health ministries.

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The adjuvanticity of aluminum hydroxide and calcium phosphate on the antibody response in mice towards the venom of the snake Bothrops asper was studied. It was found that, in vitro, most of the venom proteins are similarly adsorbed by both mineral salts, with the exception of some basic phospholipases A2, which are better adsorbed by calcium phosphate. After injection, the adjuvants promoted a slow release of the venom, as judged by the lack of acute toxicity when lethal doses of venom were administered to mice.

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The opportunistic fungal pathogen Candida glabrata adheres tightly to epithelial cells in culture, mainly through the adhesin Epa1. EPA1 is the founding member of a family of up to 23 putative adhesin-encoding genes present in the C. glabrata genome.

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The color degradation of aqueous solutions of six natural red pigment extracts (elderberry, red cabbage, hibiscus, red beet, Opuntia fruits and red cochineal) used commercially as food colorants was investigated at temperatures between 50 and 90 °C. Color degradation was studied in respect to both spectral properties and visual color. The remaining absorbance at 535 nm as a function of the incubation time and temperature was used to quantify the degradation process.

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The assessment of the capacity of antivenoms to neutralize the lethal activity of snake venoms is the gold standard in the preclinical analysis of antivenom efficacy, and is routinely performed by manufacturers and quality control laboratories. However, the complexity of snake venom composition and toxicological profile demands that, for many venoms, such as those of viperid snakes and some elapids, the neutralization of lethality be complemented with the analysis of the neutralization of other relevant toxic activities, such as hemorrhagic, myotoxic, necrotizing, procoagulant and defibrinogenating effects. This expanded protocol for preclinical testing of antivenoms should be used when a new antivenom is developed or when an existing antivenom is introduced in a new geographical setting for the neutralization of either homologous or heterologous venoms.

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Purity is a characteristic that, together with effectiveness and safety, must be tested to determine the quality of biopharmaceutical products. In therapeutic immunoglobulins, such as human intravenous immunoglobulin (IVIG), purity is evaluated on the basis of physicochemical properties, and is usually assessed by chromatography and electrophoresis. However, in the case of antivenoms these methods fail to discriminate between antibodies towards venom antigens, which constitute the active substance, and antibodies towards non-venom antigens, which are the major impurities in most of the current formulations.

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