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2.
Metabolomics ; 15(9): 117, 2019 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-31440849

RESUMEN

INTRODUCTION: Chagas disease, the most important parasitic infection in Latin America, is caused by the intracellular protozoan Trypanosoma cruzi. To treat this disease, only two nitroheterocyclic compounds with toxic side effects exist and frequent treatment failures are reported. Hence there is an urgent need to develop new drugs. Recently, metabolomics has become an efficient and cost-effective strategy for dissecting drug mode of action, which has been applied to bacteria as well as parasites, such as different Trypanosome species and forms. OBJECTIVES: We assessed if the metabolomics approach can be applied to study drug action of the intracellular amastigote form of T. cruzi in a parasite-host cell system. METHODS: We applied a metabolic fingerprinting approach (DI-MS and NMR) to evaluate metabolic changes induced by six different (candidate) drugs in a parasite-host cell system. In a second part of our study, we analyzed the impact of two drugs on polar metabolites, lipid and proteins to evaluate if affected pathways can be identified. RESULTS: Metabolic signatures, obtained by the fingerprinting approach, resulted in three different clusters. Two can be explained by already known of mode actions, whereas the three experimental drugs formed a separate cluster. Significant changes induced by drug action were observed in all the three metabolic fractions (polar metabolites, lipids and proteins). We identified a general impact on the TCA cycle, but no specific pathways could be attributed to drug action, which might be caused by a high percentage of common metabolome between a eukaryotic host cell and a eukaryotic parasite. Additionally, ion suppression effects due to differences in abundance between host cells and parasites may have occurred. CONCLUSION: We validated the metabolic fingerprinting approach to a complex host-cell parasite system. This technique can potentially be applied in the early stage of drug discovery and could help to prioritize early leads or reconfirmed hits for further development.


Asunto(s)
Interacciones Huésped-Parásitos , Metabolómica/métodos , Mioblastos/parasitología , Proteómica/métodos , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Línea Celular , Metabolismo de los Lípidos , Espectroscopía de Resonancia Magnética/métodos , Espectrometría de Masas/métodos , Metaboloma , Mioblastos/metabolismo , Proteoma/química , Ratas , Trypanosoma cruzi/metabolismo , Trypanosoma cruzi/patogenicidad
3.
Phys Rev Lett ; 120(26): 262701, 2018 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-30004755

RESUMEN

The rare-earth peak in the r-process abundance pattern depends sensitively on both the astrophysical conditions and subtle changes in nuclear structure in the region. This work takes an important step towards elucidating the nuclear structure and reducing the uncertainties in r-process calculations via precise atomic mass measurements at the JYFLTRAP double Penning trap. ^{158}Nd, ^{160}Pm, ^{162}Sm, and ^{164-166}Gd have been measured for the first time, and the precisions for ^{156}Nd, ^{158}Pm, ^{162,163}Eu, ^{163}Gd, and ^{164}Tb have been improved considerably. Nuclear structure has been probed via two-neutron separation energies S_{2n} and neutron pairing energy metrics D_{n}. The data do not support the existence of a subshell closure at N=100. Neutron pairing has been found to be weaker than predicted by theoretical mass models. The impact on the calculated r-process abundances has been studied. Substantial changes resulting in a smoother abundance distribution and a better agreement with the solar r-process abundances are observed.

4.
Anaesthesia ; 73(9): 1103-1109, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29658985

RESUMEN

Viscoelastic assays such as TEG® and ROTEM® are increasingly used to guide transfusion of blood products. The EXTEM assay maximum clot firmness (MCF) is a ROTEM measure available after 25-29 min used to guide early decisions. EXTEM A10, the clot firmness at 10 min, is an accepted early surrogate, but investigators differ on whether A5, the clot firmness at 5 min, is acceptable. We re-examined this in a retrospective observational analysis of 1146 trauma patients in one centre who had ROTEM data recorded. A5 and A10 both correlated well with maximum clot firmness, with Pearson coefficients of r = 0.92 and r = 0.96, respectively. The correlations of A5, A10 and maximum clot firmness with requirement for massive transfusion were all similarly high, with c-stats of 0.87, 0.89 and 0.90, respectively. The correlations with mortality were also similar but weaker, with c-stats of 0.67, 0.69 and 0.69, respectively. Using a previously validated cut-off of A5 < 35 mm to predict massive transfusion gave a sensitivity of 95%, specificity 83%, positive predictive value 9.3% and negative predictive value 100%. Using a value of A5 < 29 mm, for a pragmatic positive predictive value of 20%, gave a sensitivity of 67%, specificity 95% and negative predictive value 99%. Whether aiming for a high sensitivity or a strong predictive value, A5 was non-inferior to A10 and actually missed fewer cases needing massive transfusion. A5 has similar utility to both A10 and maximum clot firmness as an early measure of clot firmness, and a low A5 value is strongly predictive of the need for massive transfusion.


Asunto(s)
Trastornos de la Coagulación Sanguínea/diagnóstico , Trastornos de la Coagulación Sanguínea/etiología , Transfusión Sanguínea/estadística & datos numéricos , Tromboelastografía/métodos , Heridas y Lesiones/complicaciones , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Trastornos de la Coagulación Sanguínea/mortalidad , Femenino , Mortalidad Hospitalaria , Humanos , Puntaje de Gravedad del Traumatismo , Masculino , Persona de Mediana Edad , Ontario/epidemiología , Valor Predictivo de las Pruebas , Curva ROC , Estudios Retrospectivos , Sensibilidad y Especificidad , Triaje/métodos , Heridas y Lesiones/sangre , Heridas y Lesiones/mortalidad , Adulto Joven
5.
J Opt Soc Am A Opt Image Sci Vis ; 33(3): A77-84, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26974944

RESUMEN

The asymmetric sequential color-matching technique was used to determine the shifts in chromaticity of real Munsell chips induced by four test illuminants. The reference illuminant was C. Illuminants green (G) and purple (P) induced shifts orthogonal to the Planckian locus, while illuminants S and A induced shifts along the Planckian locus. Vectors describing the shifts induced by A and S were quantitatively and qualitatively different from those due to G and P. The data suggest that physiological factors, influenced by the proximity of the Planckian locus, affect chromatic constancy under nonsimulated viewing conditions.


Asunto(s)
Pruebas de Percepción de Colores/métodos , Iluminación/métodos , Adulto , Color , Pruebas de Percepción de Colores/instrumentación , Femenino , Humanos , Iluminación/instrumentación , Masculino , Persona de Mediana Edad , Adulto Joven
6.
J Opt Soc Am A Opt Image Sci Vis ; 31(4): A350-6, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24695193

RESUMEN

The link between chromatic constancy (compensation for hue and saturation shifts) and lightness constancy (compensation for a change in surface reflectance) was tested theoretically by computing cone contrasts and by asymmetric matching experiments. The effect of a thin achromatic line (a frame) around the test sample was tested empirically. When the samples were outlined by the frame, lightness constancy was increased and chromatic constancy reduced (p<0.001). Changes in luminance are more likely to be compensated when the luminance contrast edge around the test stimulus is disturbed as with the addition of an achromatic frame.


Asunto(s)
Sensibilidad de Contraste , Luz , Células Fotorreceptoras Retinianas Conos/citología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad
7.
Reprod Domest Anim ; 49(6): 894-8, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25132093

RESUMEN

Poor reproductive performance of Merino ewe flocks when mated to Border Leicester rams during spring may be due to seasonality of the Border Leicester breed. Two approaches were taken to test this assumption. Six young (12 months old) or six mixed-age (12, 24 and ≥36 months old) Border Leicester rams were either treated or not treated with melatonin implants (2 × 2 design) 6 weeks before the four groups of rams were each put with approximately 300 Merino ewes for an 8-week mating period. Implants were inserted in early September (experiment 1). The second approach was to yard or not yard ewes and mixed-age rams on several occasions during the first 3 weeks of the mating period (experiment 2). Pregnancy rate and twinning percentage were assessed by ultrasonography. In experiment 1, melatonin treatment in young rams increased (p < 0.001) pregnancy rate from 5.0% to 92.6%, but mixed-age rams did not respond (90.7% vs 89.5% for melatonin and non-melatonin treatments, respectively). Twinning rate was similar (p > 0.05) for ewes mated to either melatonin or non-melatonin-treated young rams (36.8% vs 40.0%, respectively), whereas melatonin significantly improved (p < 0.05) twinning rate in those ewes mated to mixed-age rams (49.1% vs 36.1%). After 6 weeks of melatonin treatment, scrotal circumference was greater (p < 0.05) in both young and mixed-aged rams than in untreated counterparts. In experiment 2, yarding of ewes and rams overnight on several occasions early in the mating period reduced (p < 0.001) pregnancy rate compared with non-yarded counterparts (89.5% vs 65.5%). Twinning rate was not affected (37.7% vs 36.1%, respectively). In summary, melatonin treatment of Border Leicester rams significantly improved flock reproductive performance in spring due to improved pregnancy rates with young rams and improved litter size with mixed-age rams.


Asunto(s)
Fármacos para la Fertilidad Masculina/farmacología , Melatonina/farmacología , Ovinos/fisiología , Animales , Implantes de Medicamentos , Femenino , Masculino , Embarazo , Índice de Embarazo , Embarazo Múltiple/efectos de los fármacos , Estaciones del Año
8.
Appl Environ Microbiol ; 79(18): 5480-7, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23835170

RESUMEN

Aspergillus oryzae has been used in the food and beverage industry for centuries, and industrial strains have been produced by multiple rounds of selection. Targeted gene deletion technology is particularly useful for strain improvement in such strains, particularly when they do not have a well-characterized meiotic cycle. Phenotypes of an Aspergillus nidulans strain null for the CreB deubiquitinating enzyme include effects on growth and repression, including increased activity levels of various enzymes. We show that Aspergillus oryzae contains a functional homologue of the CreB deubiquitinating enzyme and that a null strain shows increased activity levels of industrially important secreted enzymes, including cellulases, xylanases, amylases, and proteases, as well as alleviated inhibition of spore germination on glucose medium. Reverse transcription-quantitative PCR (RT-qPCR) analysis showed that the increased levels of enzyme activity in both Aspergillus nidulans and Aspergillus oryzae are mirrored at the transcript level, indicating transcriptional regulation. We report that Aspergillus oryzae DAR3699, originally isolated from soy fermentation, has a similar phenotype to that of a creB deletion mutant of the RIB40 strain, and it contains a mutation in the creB gene. Collectively, the results for Aspergillus oryzae, Aspergillus nidulans, Trichoderma reesei, and Penicillium decumbens show that deletion of creB may be broadly useful in diverse fungi for increasing production of a variety of enzymes.


Asunto(s)
Aspergillus oryzae/enzimología , Aspergillus oryzae/genética , Eliminación de Gen , Hidroliasas/metabolismo , Proteasas Ubiquitina-Específicas/genética , Aspergillus nidulans/genética , Aspergillus oryzae/crecimiento & desarrollo , Perfilación de la Expresión Génica , Penicillium/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Esporas Fúngicas/crecimiento & desarrollo , Trichoderma/genética
9.
Reprod Fertil Dev ; 25(8): 1216-23, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23257568

RESUMEN

Inclusion of high levels of the high-fibre ingredient sugar-beet pulp in pre-mating diets has been shown to increase gonadotrophin concentrations and improve oocyte quality in nulliparous pigs (gilts). This study evaluated the effects of two alternative fibre sources on reproductive performance in gilts. Gilts received one of three diets from 3 weeks before puberty stimulation until Day 19 of the first oestrous cycle: control (39 g kg⁻¹ fibre), bran (500 g kg⁻¹ wheat bran, 65 g kg⁻¹ fibre) or lupin (350 g kg⁻¹ lupin, 118 g kg⁻¹ crude fibre). Diet did not affect circulating LH concentrations or ovarian follicle size. However, a higher percentage of oocytes collected from lupin-supplemented gilts reached metaphase II in vitro compared with those collected from bran-fed or control gilts (89±5% versus 72±5% and 66±5%, respectively; P<0.05). Furthermore, in a second experiment, gilts fed the same lupin-based diet before mating had improved embryo survival (92±5%) on Day 28 after mating compared with control gilts (76±4%; P<0.05). Therefore, feeding a high-fibre diet before mating can improve oocyte quality in gilts without changes in circulating LH, but this effect is dependent on the fibre source.


Asunto(s)
Fibras de la Dieta , Ectogénesis , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Lupinus/química , Fenómenos Fisiologicos Nutricionales Maternos , Oogénesis , Sus scrofa/fisiología , Mataderos , Animales , Cruzamientos Genéticos , Fibras de la Dieta/uso terapéutico , Técnicas de Cultivo de Embriones/veterinaria , Femenino , Desarrollo Fetal , Reabsorción del Feto/prevención & control , Inseminación Artificial/veterinaria , Oocitos/citología , Embarazo , Desarrollo Sexual , Australia del Sur , Sus scrofa/crecimiento & desarrollo , Porcinos , Enfermedades de los Porcinos/prevención & control , Triticum/química
10.
Int J Parasitol ; 52(12): 775-786, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36228748

RESUMEN

The Nile perch (Lates niloticus) is a notorious invasive species. The introductions of Nile perch into several lakes and rivers in the Lake Victoria region led to the impoverishment of trophic food webs, particularly well documented in Lake Victoria. Additionally, its parasites were co-introduced, including Dolicirroplectanum lacustre (Monogenea, Diplectanidae). Dolicirroplectanum lacustre is the single monogenean gill parasite of latid fishes (Lates spp.) inhabiting several major African freshwater systems. We examined the intra-specific diversification of D. lacustre from Lates niloticus in Lake Albert, Uganda (native range) and Lake Victoria (introduced range) by assessing morphological and genetic differentiation, and microhabitat preference. We expected reduced morphological and genetic diversity for D. lacustre in Lake Victoria compared with Lake Albert, as a result of the historical introductions. We found that D. lacustre displayed high morphological variability within and between African freshwaters, with two morphotypes identified, as in former studies. The single shared morphotype between Lake Albert and Lake Victoria displayed similar levels of haplotype and nucleotide diversity between the lakes. Mitonuclear discordance within the morphotypes of D. lacustre indicates an incomplete reproductive barrier between the morphotypes. The diversification in the mitochondrial gene portion is directly linked with the morphotypes, while the nuclear gene portions indicate conspecificity. Based on our results, we reported reduced genetic and morphological diversity, potentially being a result of a founder effect in Lake Victoria.


Asunto(s)
Parásitos , Percas , Perciformes , Trematodos , Animales , Branquias , Lagos , Trematodos/genética
11.
Anaesthesia ; 66(8): 682-8, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21749341

RESUMEN

There is a lack of independent data regarding the accuracy of isoflurane vaporisers in current clinical use. We studied the accuracy of 10 isoflurane vaporisers (six Penlon Sigma Delta, four Datex-Ohmeda Isotec 5) taken from our operating theatres and anaesthetic rooms. Isoflurane output was measured at a range of fresh gas flow rates using both 100% oxygen and a 1:2 oxygen:nitrous oxide mixture as carrier gas. Within a clinical range of fresh gas flow rates (1-6 l.min(-1)) the worst relative output deviation of each vaporiser was at least ±20%, with under-delivery of isoflurane being commoner than over-delivery. Relative output deviation ranged from -62% to +21%, which could lead to a risk of awareness or overdose. Despite the existence of an in-house calibration schedule, the vaporisers we found in current clinical use under- or occasionally over-delivered isoflurane to a dangerous and unpredictable extent.


Asunto(s)
Anestésicos por Inhalación/administración & dosificación , Isoflurano/administración & dosificación , Nebulizadores y Vaporizadores/normas , Esquema de Medicación , Portadores de Fármacos , Humanos , Oxígeno/administración & dosificación
12.
Anim Reprod Sci ; 231: 106804, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34271495

RESUMEN

This study was conducted to test the hypothesis that between year variability in reproductive response to melatonin treatment of young Border Leicester (BL) rams in spring was related to sexual maturity at the time of treatment. Two variables of sexual maturity (mating behaviour and semen quality) were examined. In Experiment 1, mating activity of melatonin-treated and untreated rams was examined at two sites before a flock mating at one site. In Experiment 2, testosterone concentrations, semen quality and variables of in vitro fertilising capacity were examined. In Experiment 1, melatonin treatment did not alter sexual behaviour (latency to nose, total nosings, courtings including Flehmen expression, attempted mounts, mounts, ejaculations) with the exception of a lesser (P < 0.05) Flehmen expression at Site 1 whereas values for most variables were greater (P < 0.05) at Site 2. Treatment resulted in a greater pregnancy rate (89 % and 82 %, respectively; P < 0.05) and advanced distribution of pregnancies (P < 0.001) at Site 1. Testicular size and testosterone concentrations were also greater (P < 0.05) as a result of melatonin treatment in spring whilst the reverse occurred in autumn. In Experiment 2, sperm motility and in vitro fertilising capacity were greater (P < 0.05) and acrosome damage less (P < 0.05) as a result of melatonin treatment. In conclusion, variability in age at sexual maturity of young BL rams at spring mating can be reduced with melatonin treatment and is associated with differences in sexual behaviour, testicular growth, testosterone concentrations, and sperm quality.


Asunto(s)
Fertilidad/efectos de los fármacos , Melatonina/farmacología , Análisis de Semen/veterinaria , Conducta Sexual Animal/efectos de los fármacos , Ovinos , Envejecimiento , Animales , Fertilidad/fisiología , Masculino , Estaciones del Año , Maduración Sexual
13.
Anim Reprod Sci ; 226: 106715, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33571748

RESUMEN

Percentages of lamb mortalities prior to weaning are a significant and persistent problem for the Australian sheep industry. Maternal caffeine supplementation reduced stillbirths and improved viability in piglets; however, the efficacy of caffeine in enhancing viability and lamb survival is equivocal. The aim of this study was to determine the optimal concentration and duration of maternal caffeine supplementation to improve lamb viability; time to stand and suck with consumption of colostrum occurring, as well as survival to weaning. Multiparous Merino ewes were supplemented with either 0 (CTL), 10 (C10) or 20 mg/kg (C20) body weight (BW) caffeine in feed after day 120 of gestation (dG), or 20 mg/kg BW (LC20) caffeine from dG 142 until parturition. Ewes were housed indoors in individual lambing pens from dG 130 to 72 -h post-partum (pp). Values for pp ewe and lamb variables were analysed using a generalised linear mixed model in IBM SPSS version 25. While ewes within the CTL, C10 and LC20 groups consumed more caffeine compared to C20 ewes (P =  0.001), lambs of C20 ewes had greater rectal temperatures at 20 -h pp (P =  0.021), greater 4 -h serum IgG concentrations (P =  0.041), a longer latency to first sucking bout (P =  0.030), and a greater number of sucking attempts (P =  0.044) compared to lambs from CTL, C10 and LC20 ewes. These results indicate that caffeine supplementation during late-gestation stimulates neonatal lambs as a result of increased sucking (4 -h serum IgG) and increased temperatures within the first 24 -h.


Asunto(s)
Cafeína/farmacología , Suplementos Dietéticos , Ovinos/fisiología , Sobrevida , Alimentación Animal/análisis , Animales , Animales Recién Nacidos , Regulación de la Temperatura Corporal , Dieta/veterinaria , Femenino , Embarazo
14.
J Exp Med ; 188(9): 1611-9, 1998 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-9802973

RESUMEN

Natural killer (NK) cells are thought to provide the first line of defence against tumors, particularly major histocompatibility complex (MHC) class I- variants. We have confirmed in C57BL/6 (B6) mice lacking perforin that peritoneal growth of MHC class I- RMA-S tumor cells in unprimed mice is controlled by perforin-dependent cytotoxicity mediated by CD3(-) NK1.1(+) cells. Furthermore, we demonstrate that B6 mice lacking tumor necrosis factor (TNF) are also significantly defective in their rejection of RMA-S, despite the fact that RMA-S is insensitive to TNF in vitro and that spleen NK cells from B6 and TNF-deficient mice are equally lytic towards RMA-S. NK cell recruitment into the peritoneum was abrogated in TNF-deficient mice challenged with RMA-S or RM-1, a B6 MHC class I- prostate carcinoma, compared with B6 or perforin-deficient mice. The reduced NK cell migration to the peritoneum of TNF-deficient mice correlated with the defective NK cell response to tumor in these mice. By contrast, a lack of TNF did not affect peptide-specific cytotoxic T lymphocyte-mediated rejection of tumor from the peritoneum of preimmunized mice. Overall, these data show that NK cells delivering perforin are the major effectors of class I- tumor rejection in the peritoneum, and that TNF is specifically critical for their recruitment to the peritoneum.


Asunto(s)
Células Asesinas Naturales/inmunología , Neoplasias Experimentales/inmunología , Peritoneo/inmunología , Factor de Necrosis Tumoral alfa/inmunología , Animales , Movimiento Celular/inmunología , Citotoxicidad Inmunológica , Rechazo de Injerto/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Técnicas In Vitro , Células Asesinas Naturales/fisiología , Masculino , Glicoproteínas de Membrana/deficiencia , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Trasplante de Neoplasias , Perforina , Proteínas Citotóxicas Formadoras de Poros , Factor de Necrosis Tumoral alfa/deficiencia , Factor de Necrosis Tumoral alfa/genética
15.
J Exp Med ; 191(1): 89-96, 2000 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-10620607

RESUMEN

Tumor necrosis factor (TNF) and Fas ligand (FasL) play major roles in the homeostasis of the peripheral immune system. This becomes dramatically obvious in the absence of a functional FasL. Mice with such a deficiency develop a profound lymphadenopathy, splenomegaly, hypergammaglobulinemia, and strain-dependent systemic autoimmune disease, and succumb to premature death. It is consequently termed generalized lymphoproliferative disorder (gld). By contrast, TNF deficiency alone does not result in a striking phenotype. Thus, we sought to determine what role TNF might play in contributing to the gld phenotype by creating C57BL/6.gld.TNF(-/-) mice. Contrary to the expected outcome, mice deficient for both FasL and TNF had a substantially milder gld phenotype with regard to mortality, lymphoaccumulation, germinal center formation, and hypergammaglobulinemia. To confirm these data in a strain highly permissive for the phenotype, C3H/HeJ.gld and C3H.HeJ.lpr mice were treated with a TNF-specific monoclonal antibody. This transient neutralization of TNF also resulted in a significantly attenuated lymphoproliferative phenotype. We conclude that TNF is necessary for the full manifestation of the lymphoproliferative disorder, in particular playing a critical role in lymphoaccumulation. Most importantly, absence of TNF protects gld mice against premature death.


Asunto(s)
Trastornos Linfoproliferativos/etiología , Factor de Necrosis Tumoral alfa/fisiología , Animales , Anticuerpos Monoclonales/inmunología , Antígenos CD/metabolismo , Proteína Ligando Fas , Centro Germinal/fisiología , Glicoproteínas de Membrana/fisiología , Ratones , Ratones Endogámicos C3H , Ratones Noqueados , Fenotipo , Receptores del Factor de Necrosis Tumoral/fisiología , Receptores Tipo II del Factor de Necrosis Tumoral
16.
Parasitology ; 137(6): 899-917, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20152063

RESUMEN

Iron is almost ubiquitous in living organisms due to the utility of its redox chemistry. It is also dangerous as it can catalyse the formation of reactive free radicals - a classical double-edged sword. In this review, we examine the uptake and usage of iron by trypanosomatids and discuss how modulation of host iron metabolism plays an important role in the protective response. Trypanosomatids require iron for crucial processes including DNA replication, antioxidant defence, mitochondrial respiration, synthesis of the modified base J and, in African trypanosomes, the alternative oxidase. The source of iron varies between species. Bloodstream-form African trypanosomes acquire iron from their host by uptake of transferrin, and Leishmania amazonensis expresses a ZIP family cation transporter in the plasma membrane. In other trypanosomatids, iron uptake has been poorly characterized. Iron-withholding responses by the host can be a major determinant of disease outcome. Their role in trypanosomatid infections is becoming apparent. For example, the cytosolic sequestration properties of NRAMP1, confer resistance against leishmaniasis. Conversely, cytoplasmic sequestration of iron may be favourable rather than detrimental to Trypanosoma cruzi. The central role of iron in both parasite metabolism and the host response is attracting interest as a possible point of therapeutic intervention.


Asunto(s)
Hierro/metabolismo , Leishmania/metabolismo , Leishmaniasis/metabolismo , Trypanosoma/metabolismo , Tripanosomiasis/metabolismo , Animales
17.
Science ; 187(4180): 951-3, 1975 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-49925

RESUMEN

Sensitization of Lewis rats with whole central nervous system tissue or with purified myelin induced both experimental allergic encephalomyelitis (EAE) and a serum factor which inhibited myelin formation in vitro. Sensitization with the encephalitogenic factor, myelin basic protein, induced EAE, but not the myelination inhibition factor. Sensitization with cerebroside induced neither EAE nor myelination inhibition factor. The serums from control animals without EAE as well as from animals sensitized with all of the above antigens blocked evoked electrical responses in vitro.


Asunto(s)
Anticuerpos , Encefalomielitis Autoinmune Experimental/inmunología , Potenciales Evocados , Vaina de Mielina/inmunología , Proteínas del Tejido Nervioso/inmunología , Animales , Antígenos , Cerebelo/fisiopatología , Corteza Cerebral/fisiopatología , Cerebrósidos/inmunología , Encefalomielitis Autoinmune Experimental/fisiopatología , Inmunización , Masculino , Proteína Básica de Mielina/inmunología , Ratas , Ratas Endogámicas Lew
18.
Br J Educ Psychol ; 79(Pt 4): 735-47, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19288977

RESUMEN

BACKGROUND: Data from national test results suggests that children who are learning English as an additional language (EAL) experience relatively lower levels of educational attainment in comparison to their monolingual, English-speaking peers. AIMS: The relative underachievement of children who are learning EAL demands that the literacy needs of this group are identified. To this end, this study aimed to explore the reading- and comprehension-related skills of a group of EAL learners. SAMPLE: Data are reported from 92 Year 3 pupils, of whom 46 children are learning EAL. METHOD: Children completed standardized measures of reading accuracy and comprehension, listening comprehension, and receptive and expressive vocabulary. RESULTS: Results indicate that many EAL learners experience difficulties in understanding written and spoken text. These comprehension difficulties are not related to decoding problems but are related to significantly lower levels of vocabulary knowledge experienced by this group. CONCLUSIONS: Many EAL learners experience significantly lower levels of English vocabulary knowledge which has a significant impact on their ability to understand written and spoken text. Greater emphasis on language development is therefore needed in the school curriculum to attempt to address the limited language skills of children learning EAL.


Asunto(s)
Comprensión , Multilingüismo , Rendimiento Escolar Bajo , Logro , Niño , Inglaterra , Femenino , Humanos , Desarrollo del Lenguaje , Pruebas del Lenguaje , Masculino , Lectura , Factores Sexuales , Medio Social , Percepción del Habla , Conducta Verbal , Vocabulario
19.
Eur J Med Chem ; 173: 63-75, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-30986572

RESUMEN

The novel benzimidazol-2-yl-fur-5-yl-(1,2,3)-triazolyl dimeric series with aliphatic and aromatic central linkers was successfully prepared with the aim of assessing binding affinity to DNA/RNA and antitrypanosomal activity. UV-Visible spectroscopy, thermal denaturation showed interaction of heterocyclic bis-amidines with ctDNA. Circular dichroism studies indicated uniform orientation of heterocyclic bis-amidines along the chiral double helix axis, revealing minor groove binding as the dominant binding mode. The amidino fragment and 1,4-bis(oxymethylene)phenyl spacer were the main determinants of activity against Trypanosoma brucei. The bis-benzimidazole imidazoline 15c, which had antitrypanosomal potency in the submicromolar range and DNA interacting properties, emerged as a candidate for further structural optimization to obtain more effective agents to combat trypanosome infections.


Asunto(s)
Bencimidazoles/farmacología , Tripanocidas/farmacología , Trypanosoma brucei brucei/efectos de los fármacos , Bencimidazoles/síntesis química , Bencimidazoles/química , Sitios de Unión/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Relación Estructura-Actividad , Tripanocidas/síntesis química , Tripanocidas/química
20.
World J Biol Psychiatry ; 20(9): 670-682, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-29425059

RESUMEN

Objectives: Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two syndromes that are caused by the same chromosomal deletion on 15q11.2-q13. Due to methylation patterns, different genes are responsible for the two distinct phenotypes resulting in the disorders. Patients of both disorders exhibit hypotonia in neonatal stage, delay in development and hypopigmentation. Typical features for PWS include hyperphagia, which leads to obesity, the major cause of mortality, and hypogonadism. In AS, patients suffer from a more severe developmental delay, they have a distinctive behaviour that is often described as unnaturally happy, and a tendency for epileptic seizures. For both syndromes, we identified and visualised molecular downstream pathways of the deleted genes that could give insight on the development of the clinical features.Methods: This was done by consulting literature, genome browsers and pathway databases to identify molecular interactions and to construct downstream pathways.Results: A pathway visualisation was created and uploaded to the open pathway database WikiPathways covering all molecular pathways that were found.Conclusions: The visualisation of the downstream pathways of PWS- and AS-deleted genes shows that some of the typical symptoms are caused by multiple genes and reveals critical gaps in the current knowledge.


Asunto(s)
Síndrome de Angelman/genética , Rotura Cromosómica , Cromosomas Humanos Par 15/genética , Síndrome de Prader-Willi/genética , Deleción Cromosómica , Metilación de ADN , Visualización de Datos , Genómica , Humanos
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