Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 764
Filtrar
Más filtros

Intervalo de año de publicación
1.
Nature ; 612(7940): 528-533, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36477538

RESUMEN

Sexual reproduction and meiotic sex are deeply rooted in the eukaryotic tree of life, but mechanisms determining sex or mating types are extremely varied and are only well characterized in a few model organisms1. In malaria parasites, sexual reproduction coincides with transmission to the vector host. Sex determination is non-genetic, with each haploid parasite capable of producing either a male or a female gametocyte in the human host2. The hierarchy of events and molecular mechanisms that trigger sex determination and maintenance of sexual identity are yet to be elucidated. Here we show that the male development 1 (md1) gene is both necessary and sufficient for male fate determination in the human malaria parasite Plasmodium falciparum. We show that Md1 has a dual function stemming from two separate domains: in sex determination through its N terminus and in male development from its conserved C-terminal LOTUS/OST-HTH domain. We further identify a bistable switch at the md1 locus, which is coupled with sex determination and ensures that the male-determining gene is not expressed in the female lineage. We describe one of only a few known non-genetic mechanisms of sex determination in a eukaryote and highlight Md1 as a potential target for interventions that block malaria transmission.


Asunto(s)
Regulación de la Expresión Génica , Malaria Falciparum , Malaria , Parásitos , Procesos de Determinación del Sexo , Transcripción Genética , Animales , Humanos , Malaria/parasitología , Malaria Falciparum/parasitología , Parásitos/genética , Plasmodium falciparum/genética , Reproducción , Masculino , Femenino , Procesos de Determinación del Sexo/genética , Caracteres Sexuales
2.
Hum Genomics ; 18(1): 16, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38326874

RESUMEN

BACKGROUND: Diabetes is a spectrum of metabolic diseases affecting millions of people worldwide. The loss of pancreatic ß-cell mass by either autoimmune destruction or apoptosis, in type 1-diabetes (T1D) and type 2-diabetes (T2D), respectively, represents a pathophysiological process leading to insulin deficiency. Therefore, therapeutic strategies focusing on restoring ß-cell mass and ß-cell insulin secretory capacity may impact disease management. This study took advantage of powerful integrative bioinformatic tools to scrutinize publicly available diabetes-associated gene expression data to unveil novel potential molecular targets associated with ß-cell dysfunction. METHODS: A comprehensive literature search for human studies on gene expression alterations in the pancreas associated with T1D and T2D was performed. A total of 6 studies were selected for data extraction and for bioinformatic analysis. Pathway enrichment analyses of differentially expressed genes (DEGs) were conducted, together with protein-protein interaction networks and the identification of potential transcription factors (TFs). For noncoding differentially expressed RNAs, microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), which exert regulatory activities associated with diabetes, identifying target genes and pathways regulated by these RNAs is fundamental for establishing a robust regulatory network. RESULTS: Comparisons of DEGs among the 6 studies showed 59 genes in common among 4 or more studies. Besides alterations in mRNA, it was possible to identify differentially expressed miRNA and lncRNA. Among the top transcription factors (TFs), HIPK2, KLF5, STAT1 and STAT3 emerged as potential regulators of the altered gene expression. Integrated analysis of protein-coding genes, miRNAs, and lncRNAs pointed out several pathways involved in metabolism, cell signaling, the immune system, cell adhesion, and interactions. Interestingly, the GABAergic synapse pathway emerged as the only common pathway to all datasets. CONCLUSIONS: This study demonstrated the power of bioinformatics tools in scrutinizing publicly available gene expression data, thereby revealing potential therapeutic targets like the GABAergic synapse pathway, which holds promise in modulating α-cells transdifferentiation into ß-cells.


Asunto(s)
Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Insulinas , MicroARNs , ARN Largo no Codificante , Humanos , ARN Largo no Codificante/genética , Redes Reguladoras de Genes/genética , Perfilación de la Expresión Génica , MicroARNs/genética , Diabetes Mellitus Tipo 2/genética , Factores de Transcripción/genética , Insulinas/genética , Biología Computacional , Proteínas Portadoras/genética , Proteínas Serina-Treonina Quinasas/genética
3.
Artículo en Inglés | MEDLINE | ID: mdl-38904778

RESUMEN

INTRODUCTION: Prosthetic valve endocarditis (PVE) is a serious complication of prosthetic valve implantation, with an estimated yearly incidence of at least 0.4-1.0%. The Duke criteria and subsequent modifications have been developed as a diagnostic framework for infective endocarditis (IE) in clinical studies. However, their sensitivity and specificity are limited, especially for PVE. Furthermore, their most recent versions (ESC2015 and ESC2023) include advanced imaging modalities, e.g., cardiac CTA and [18F]FDG PET/CT as major criteria. However, despite these significant changes, the weighing system using major and minor criteria has remained unchanged. This may have introduced bias to the diagnostic set of criteria. Here, we aimed to evaluate and improve the predictive value of the modified Duke/ESC 2015 (MDE2015) criteria by using machine learning algorithms. METHODS: In this proof-of-concept study, we used data of a well-defined retrospective multicentre cohort of 160 patients evaluated for suspected PVE. Four machine learning algorithms were compared to the prediction of the diagnosis according to the MDE2015 criteria: Lasso logistic regression, decision tree with gradient boosting (XGBoost), decision tree without gradient boosting, and a model combining predictions of these (ensemble learning). All models used the same features that also constitute the MDE2015 criteria. The final diagnosis of PVE, based on endocarditis team consensus using all available clinical information, including surgical findings whenever performed, and with at least 1 year follow up, was used as the composite gold standard. RESULTS: The diagnostic performance of the MDE2015 criteria varied depending on how the category of 'possible' PVE cases were handled. Considering these cases as positive for PVE, sensitivity and specificity were 0.96 and 0.60, respectively. Whereas treating these cases as negative, sensitivity and specificity were 0.74 and 0.98, respectively. Combining the approaches of considering possible endocarditis as positive and as negative for ROC-analysis resulted in an excellent AUC of 0.917. For the machine learning models, the sensitivity and specificity were as follows: logistic regression, 0.92 and 0.85; XGBoost, 0.90 and 0.85; decision trees, 0.88 and 0.86; and ensemble learning, 0.91 and 0.85, respectively. The resulting AUCs were, in the same order: 0.938, 0.937, 0.930, and 0.941, respectively. DISCUSSION: In this proof-of-concept study, machine learning algorithms achieved improved diagnostic performance compared to the major/minor weighing system as used in the MDE2015 criteria. Moreover, these models provide quantifiable certainty levels of the diagnosis, potentially enhancing interpretability for clinicians. Additionally, they allow for easy incorporation of new and/or refined criteria, such as the individual weight of advanced imaging modalities such as CTA or [18F]FDG PET/CT. These promising preliminary findings warrant further studies for validation, ideally in a prospective cohort encompassing the full spectrum of patients with suspected IE.

4.
Ann Oncol ; 34(9): 772-782, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37399894

RESUMEN

BACKGROUND: Patients with metastatic castration-resistant prostate cancer (mCRPC) and BRCA alterations have poor outcomes. MAGNITUDE found patients with homologous recombination repair gene alterations (HRR+), particularly BRCA1/2, benefit from first-line therapy with niraparib plus abiraterone acetate and prednisone (AAP). Here we report longer follow-up from the second prespecified interim analysis (IA2). PATIENTS AND METHODS: Patients with mCRPC were prospectively identified as HRR+ with/without BRCA1/2 alterations and randomized 1 : 1 to niraparib (200 mg orally) plus AAP (1000 mg/10 mg orally) or placebo plus AAP. At IA2, secondary endpoints [time to symptomatic progression, time to initiation of cytotoxic chemotherapy, overall survival (OS)] were assessed. RESULTS: Overall, 212 HRR+ patients received niraparib plus AAP (BRCA1/2 subgroup, n = 113). At IA2 with 24.8 months of median follow-up in the BRCA1/2 subgroup, niraparib plus AAP significantly prolonged radiographic progression-free survival {rPFS; blinded independent central review; median rPFS 19.5 versus 10.9 months; hazard ratio (HR) = 0.55 [95% confidence interval (CI) 0.39-0.78]; nominal P = 0.0007} consistent with the first prespecified interim analysis. rPFS was also prolonged in the total HRR+ population [HR = 0.76 (95% CI 0.60-0.97); nominal P = 0.0280; median follow-up 26.8 months]. Improvements in time to symptomatic progression and time to initiation of cytotoxic chemotherapy were observed with niraparib plus AAP. In the BRCA1/2 subgroup, the analysis of OS with niraparib plus AAP demonstrated an HR of 0.88 (95% CI 0.58-1.34; nominal P = 0.5505); the prespecified inverse probability censoring weighting analysis of OS, accounting for imbalances in subsequent use of poly adenosine diphosphate-ribose polymerase inhibitors and other life-prolonging therapies, demonstrated an HR of 0.54 (95% CI 0.33-0.90; nominal P = 0.0181). No new safety signals were observed. CONCLUSIONS: MAGNITUDE, enrolling the largest BRCA1/2 cohort in first-line mCRPC to date, demonstrated improved rPFS and other clinically relevant outcomes with niraparib plus AAP in patients with BRCA1/2-altered mCRPC, emphasizing the importance of identifying this molecular subset of patients.


Asunto(s)
Acetato de Abiraterona , Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Prednisona , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Proteína BRCA1/genética , Reparación del ADN por Recombinación , Resultado del Tratamiento , Proteína BRCA2/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico
5.
Ann Oncol ; 34(5): 477-485, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36858151

RESUMEN

BACKGROUND: The first interim analysis of the phase III, randomized, double-blind, placebo-controlled, multinational TITAN study demonstrated improved overall survival (OS) and radiographic progression-free survival (rPFS) with apalutamide added to ongoing androgen deprivation therapy (ADT) in patients with metastatic castration-sensitive prostate cancer. The final analysis confirmed improvement in OS and other long-term outcomes. We evaluated prostate-specific antigen (PSA) kinetics and the association between PSA decline and outcomes in patients with metastatic castration-sensitive prostate cancer from TITAN. PATIENTS AND METHODS: Patients received apalutamide (240 mg/day) or placebo plus ADT (1 : 1). This post hoc exploratory analysis evaluated PSA kinetics and decline in relation to rPFS (22.7 months' follow-up) and OS, time to PSA progression, and time to castration resistance (44.0 months' follow-up) in patients with or without confirmed PSA decline using a landmark analysis, the Kaplan-Meier method, and Cox proportional hazards model. RESULTS: One thousand and fifty-two patients (apalutamide, 525; placebo, 527) were enrolled. Best confirmed PSA declines (≥50% or ≥90% from baseline or to ≤0.2 ng/ml) were achieved at any time during the study in 90%, 73%, and 68% of apalutamide-treated versus 55%, 29%, and 32% of placebo-treated patients, respectively. By 3 months of apalutamide treatment, best deep PSA decline of ≥90% or to ≤0.2 ng/ml occurred in 59% and 51% of apalutamide- and in 13% and 18% of placebo-treated patients, respectively. Achievement of deep PSA decline at landmark 3 months of apalutamide treatment was associated with longer OS [hazard ratio (HR) 0.35; 95% confidence interval (CI) 0.25-0.48), rPFS (HR 0.44; 95% CI 0.30-0.65), time to PSA progression (HR 0.31; 95% CI 0.22-0.44), and time to castration resistance (HR 0.38; 95% CI 0.27-0.52) compared with no decline (P < 0.0001 for all). Similar results were observed at landmark 6 and 12 months of apalutamide treatment. CONCLUSIONS: Apalutamide plus ADT demonstrated a robust (rapid, deep, and durable) PSA decline that was associated with improved clinical outcomes, including long-term survival.


Asunto(s)
Antígeno Prostático Específico , Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Antagonistas de Andrógenos/uso terapéutico , Andrógenos/uso terapéutico , Castración
6.
J Endocrinol Invest ; 46(7): 1459-1464, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36645638

RESUMEN

PURPOSE: Simultaneous pancreas-kidney transplantation (SPKT) remains the best treatment option in patients with type 1 diabetes and chronic kidney failure. There are only a few studies addressing the potential ischemic deterioration of peripheral arterial disease (PAD) due to blood diverting from the iliac artery to the kidney graft. We aimed to evaluate diabetic foot lesions and PAD evolution in SPKT recipients and investigate if they are more frequent in ipsilateral lower limb of kidney graft. METHODS: We developed a retrospective cohort, including patients submitted to SPKT in our tertiary center, between 2000 and 2017. Diabetic foot lesions and PAD frequencies were compared in the period before and after transplantation. RESULTS: Two hundred and eleven patients were included, 50.2% (n = 106) female, with a median age at transplantation of 35 years (IQR 9). After a median follow-up period of 10 years (IQR 7), patient, kidney, and pancreatic graft survival were 90.5% (n = 191), 83.4% (n = 176), and 74.9% (n = 158), respectively. Before transplant, 2.8% (n = 6) had PAD and 5.3% (n = 11) had history of foot lesions. In post-transplant period, 17.1% (n = 36) patients presented PAD and 25.6% (n = 54) developed diabetic foot ulcers, 47.6% (n = 35) of which in the ipsilateral and 53.3% (n = 40) in the contralateral lower limb of the kidney graft (p = 0.48). Nine patients (4.3%) underwent major lower limb amputation, 3 (30%) ipsilateral and 7 (70%) contralateral to the kidney graft (p = 0.29). CONCLUSIONS: Diabetic foot lesions were not more frequent in the ipsilateral lower limb of the kidney graft, therefore downgrading the 'steal syndrome' role in these patients.


Asunto(s)
Diabetes Mellitus Tipo 1 , Pie Diabético , Trasplante de Riñón , Enfermedad Arterial Periférica , Humanos , Femenino , Niño , Pie Diabético/etiología , Trasplante de Riñón/efectos adversos , Estudios Retrospectivos , Enfermedad Arterial Periférica/etiología , Páncreas , Resultado del Tratamiento
7.
Arch Microbiol ; 204(8): 530, 2022 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-35900475

RESUMEN

Microorganisms adapt to environmental conditions as a survival strategy for different interactions with the environment. The adaptive capacity of fungi allows them to cause disease at various sites of infection in humans. In this study, we propose digital images as responses of a complete factorial 23. Furthermore, we compared two experimental approaches: the experimental design (3D) and the checkerboard assay (2D) to know the influence of pH, glucose, and fluconazole concentration on different strains of the genus Candida. The digital images obtained from the factorial 23 were used as input in the PCA-ANOVA to analyze the results of this experimental design. pH modification in the culture medium modifies the susceptibility in some species less adapted to this type of modification. For the first time, to the best of our knowledge, digital images were used as input to PCA-ANOVA to obtain information on Candida spp.. Therefore, a higher concentration of antifungals is needed to inhibit the same strain at a lower pH. In short, we present an alternative with less use of reagents and time. In addition, the use of digital images allows obtaining information about fungal susceptibility with three or more factors.


Asunto(s)
Candida , Glucosa , Antifúngicos/farmacología , Quimiometría , Computadores , Farmacorresistencia Fúngica , Fluconazol/farmacología , Humanos , Concentración de Iones de Hidrógeno , Pruebas de Sensibilidad Microbiana
8.
J Appl Microbiol ; 130(1): 90-99, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32640074

RESUMEN

AIMS: This work aimed to estimate the growth of Myceliophthora thermophila M.7·7 in solid-state cultivation (SSC) through quantification of N-acetyl-d-glucosamine (NAG) and enzyme activity. METHODS AND RESULTS: The fungus was cultivated in sugarcane bagasse and wheat bran. A consistent statistical analysis was done to assess the reliability of experimental data. Logistic model equation was fitted to experimental data and growth parameters were estimated. The results showed strong influence of the sample size on NAG and a minimum recommended sample size was identified. Scanning electron microscopy (SEM) was used to identify the strategy of substrate colonization. Wheat bran was attacked firstly, while sugarcane bagasse was consumed after wheat bran depletion. The biomass growth was poorly estimated by secretion kinetics of α-amylase, endoglucanase, protease and xylanase, but enzyme kinetics were important for understanding substrate colonization. CONCLUSIONS: In conclusion, the NAG concentration was strongly affected by the sample size and sampling procedure. The strategy of fungal colonization on the substrates was well characterized through SEM analysis. The colonization strategy has direct influence on the kinetic parameters of the logistic model. Myceliophthora thermophila has a well-defined dynamic of enzyme secretion to degrade the substrate, although the kinetics of enzyme secretion has shown not adequate to characterize the kinetics of fungal growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper provides reliable growth kinetic parameters in the SSC of the cellulase producer fungus M. thermophila M.7·7, as well as a robust analysis on three indirect methods (NAG, enzymes and SEM) for estimation of fungal development.


Asunto(s)
Sordariales/crecimiento & desarrollo , Acetilglucosamina/metabolismo , Biomasa , Reactores Biológicos , Celulosa/metabolismo , Fibras de la Dieta/metabolismo , Proteínas Fúngicas/metabolismo , Cinética , Reproducibilidad de los Resultados , Saccharum/química , Sordariales/enzimología , Sordariales/metabolismo , Sordariales/ultraestructura
9.
Reprod Fertil Dev ; 33(5): 372-380, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33684338

RESUMEN

This study evaluated the effects of three maturation systems, namely invitro (MatV) and invivo (MatS) systems, as well as intrafollicular transfer of immature oocytes (IFIOT; MatT), on the accumulation of lipid droplets in bovine oocytes. Lipids were evaluated using confocal microscopy and transmission electron microscopy. The expression of genes related to lipid metabolism, namely acyl-CoA synthetase short chain family member 2 (ACSS2), ELOVL fatty acid elongase 1 (ELOVL1) and fatty acid binding protein 3 (FABP3), was quantified by quantitative polymerase chain reaction. The mean (±s.d.) area occupied by lipids in immature oocytes (13±2%) was similar to those matured invivo (MatS, 16±2%; MatT, 12±2%). However, there was a significant increase in lipids in oocytes in the MatV group (24±2%) compared with all other groups (P<0.001). In the ultrastructural evaluations, MatV oocytes also showed the highest lipid content. The expression of ELOVL1 and FABP3 was similar in the MatS and IFIOT groups. However, transcript levels of ACSS2 were lower in IFIOT than MatV oocytes. These results indicate, for the first time, that oocytes matured by IFIOT are similar to those matured invivo with regard to lipid accumulation, which indicates better quality than those matured invitro.


Asunto(s)
Bovinos , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Metabolismo de los Lípidos , Oocitos/crecimiento & desarrollo , Oocitos/metabolismo , Acetato CoA Ligasa/genética , Animales , Proteína 3 de Unión a Ácidos Grasos/genética , Elongasas de Ácidos Grasos/genética , Femenino , Expresión Génica , Metabolismo de los Lípidos/genética , Oocitos/ultraestructura , Folículo Ovárico/citología
10.
Ecotoxicology ; 30(9): 1841-1853, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34224071

RESUMEN

Pharmaceutical drugs have emerged as major micropollutants in aquatic ecosystems. Their presence has been systematically reported in monitoring surveys, and their wide distribution and constant presence in the wild is a direct consequence of their massive use, in both human and veterinary therapeutics. Drugs used to treat parasitic infections in livestock are major contaminants, given the amounts in which they are administered, and reach the aquatic compartment in high amounts, where they may affect non target species. Some of these drugs are prone to find their final deposit in sediments of estuarine areas, exerting their toxic effects preferentially at these locations. Sediment dwelling organisms of coastal areas, such as polychaetas, are especially prone to have their major physiological functions compromised after being exposed to pharmaceutical drugs. Ivermectin is one of the most used antiparasitic drugs, and its effects are not limited to biochemical traits, but also behavioral features may be compromised considering their neurotoxic actions. Despite these putative effects, little is known about their toxicity on polychaetas. The present study aimed to characterize the toxicity of realistic levels of ivermectin on the polychaeta Hediste diversicolor, in biochemical and behavioral terms. The obtained results showed that low levels of ivermectin are capable of causing significant disturbances in mobility and burrowing activity of exposed worms, as well as alterations of metabolic and anti-oxidant defense efficacy of exposed animals, suggesting that its environmental presence may mean a major environmental concern.


Asunto(s)
Poliquetos , Contaminantes Químicos del Agua , Animales , Antiparasitarios/toxicidad , Ecosistema , Humanos , Ivermectina/toxicidad , Estrés Oxidativo , Contaminantes Químicos del Agua/toxicidad
11.
Palliat Support Care ; 19(2): 246-256, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32867873

RESUMEN

OBJECTIVE: Expectant parents who live through perinatal loss experience intense grief, which is not always acknowledged or accepted. A screening tool to detect bereaved parents' grief reactions can guide professionals, including perinatal palliative care teams, to provide follow-up for those in need. This review's goal is to identify and synthesize the international published literature on existent instruments specifically measuring the grieving process after any perinatal loss and to identify factors that could moderate grief reactions. METHOD: Systematic review (PROSPERO # CRD42018092555) with critical synthesis. PUBMED, Cochrane, and PsycINFO databases were searched in English language articles using the keywords "perinatal" AND ("grief" OR "bereavement" OR mourning) AND ("scale" OR "questionnaire" OR "measure" OR "assessment") up to May 2018. Eligibility criteria included every study using a measure to assess perinatal grief after all kinds of perinatal losses, including validations and translations to other languages and interventions designed to alleviate grief symptoms. RESULTS: A total of 67 papers met inclusion criteria. Seven instruments measuring perinatal grief published between 1984 and 2002 are described. The Perinatal Grief Scale (PGS) was used in 53 of the selected studies. Of those, 39 analyzed factors associated with grief reactions. Six articles used PGS scores to evaluate pre- and post-bereavement interventions. Studies in English language only might have limited the number of articles. SIGNIFICANCE OF RESULTS: The PGS is the most used standardized measures to assess grief after perinatal loss. All parents living through any kind of perinatal loss should be screened.


Asunto(s)
Aflicción , Muerte Fetal , Pesar , Femenino , Humanos , Padres , Embarazo
12.
Histochem Cell Biol ; 153(1): 63-69, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31654127

RESUMEN

The genre Mycobacterium includes a series of pathological species, such as M. tuberculosis, which is important for pathology laboratories to detect for a correct diagnosis. The Ziehl-Neelsen technique (ZNT) is the most commonly histochemical method used to detect these bacilli and uses a heated mixture of carbol-fuchsine, which contains basic fuchsine and phenol. Whereas the former component is responsible for the pinkish staining of acid-fast mycobacteria, the role of phenol is not completely understood and it has been suggested that its exclusion does not impact the detection ability of the ZNT. Since phenol is highly toxic and induces several injuries, the goal of this study is to determine the detection capacity of mycobacteria through a method that excludes the use of phenol. Accordingly, the GASMoC method, a modified ZNT that employs a solution of aqueous basic fuchsine heated at 37 °C, was tested on histological samples positive for mycobacteria and the results were compared to that of the ZNT. Data demonstrated that the GASMoC method was able to detect acid-fast bacilli (AFB) in all analyzed cases. Remarkably, microscopic inspection of mycobacteria was easier when the GASMoC method was applied. In conclusion, our study demonstrates that AFB detection does not require phenol and that the GASMoC method, a phenol-free technique, may substitute the ZNT in pathology laboratories.


Asunto(s)
Mycobacterium tuberculosis/aislamiento & purificación , Coloración y Etiquetado , Histocitoquímica , Humanos
13.
Nature ; 508(7494): 72-5, 2014 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-24670644

RESUMEN

Hitherto, rings have been found exclusively around the four giant planets in the Solar System. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle. Here we report observations of a multichord stellar occultation that revealed the presence of a ring system around (10199) Chariklo, which is a Centaur--that is, one of a class of small objects orbiting primarily between Jupiter and Neptune--with an equivalent radius of 124 ± 9 kilometres (ref. 2). There are two dense rings, with respective widths of about 7 and 3 kilometres, optical depths of 0.4 and 0.06, and orbital radii of 391 and 405 kilometres. The present orientation of the ring is consistent with an edge-on geometry in 2008, which provides a simple explanation for the dimming of the Chariklo system between 1997 and 2008, and for the gradual disappearance of ice and other absorption features in its spectrum over the same period. This implies that the rings are partly composed of water ice. They may be the remnants of a debris disk, possibly confined by embedded, kilometre-sized satellites.

14.
Reprod Fertil Dev ; 32(7): 690-696, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32317093

RESUMEN

We aimed to analyse the histone acetylation status and expression profile of genes involved in histone acetylation (histone acetyltransferase 1 (HAT1), lysine acetyltransferase 2A (KAT2A), histone deacetylase 1(HDAC1), HDAC2 and HDAC3) in bovine oocytes of different competences during invitro maturation (IVM). Cumulus-oocyte complexes were recovered from two groups of follicles: minor follicles (1.0-3.0mm in diameter), classified as low competence (LC) and large follicles (6.0-8.0mm in diameter) classified as high competence (HC). Oocytes were submitted to IVM for 0, 8 and 24h and stored for analysis. Acetylation status of histone H4 on lysine K5, K6, K12 and K16 was assessed by immunohistochemistry. For gene expression, mRNA levels were determined by real-time quantitative polymerase chain reaction. All oocytes, regardless of their competence, showed a gradual decrease (P<0.05) in acetylation signals during IVM. From 0 to 8h of maturation, an increase (P<0.05) in the relative abundance of HAT1 mRNA was observed only in the HC oocytes. In this group, higher (P<0.05) mRNA levels of HDAC1 at 8h of maturation were also observed. In conclusion, in the present study, LC oocytes were shown to have adequate acetylation levels for the resumption and progression of meiosis; however, these oocytes do not have the capacity to synthesise RNA during IVM as the HC oocytes do.


Asunto(s)
Bovinos , Histona Acetiltransferasas/metabolismo , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Oocitos/enzimología , Acetilación , Animales , Células del Cúmulo/fisiología , Femenino , Histona Acetiltransferasas/genética , Histonas/metabolismo , Lisina/metabolismo , Oocitos/crecimiento & desarrollo , Oogénesis/genética , Oogénesis/fisiología , ARN Mensajero/análisis
15.
J Helminthol ; 94: e138, 2020 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-32188515

RESUMEN

A new species of Moniliformis Travassos, 1915 (Acanthocephala: Moniliformidae) is described from the hairy-tailed bolo mouse, Necromys lasiurus Lund, 1840 (Cricetidae: Sigmondontinae), captured in the Brazilian Cerrado, in Uberlândia, state of Minas Gerais, Brazil. The specimens were studied by light and scanning electron microscopy. Molecular phylogenies were inferred from partial nuclear large subunit ribosomal RNA gene sequences and partial mitochondrial cytochrome c oxidase subunit I gene. The new species is distinguished from other moniliformid species by the number of rows and number of hooks per row, size of the proboscis, size of the eggs, host species and geographical distribution. Molecular phylogenies and genetic distances analyses demonstrated that Moniliformis necromysi sp. n. forms a well-supported monophyletic group with sequences of other species of Moniliformis and is distinguished from them, which agrees with the morphological characteristics, allocating the new species to this genus and to the family Moniliformidae Van Cleave, 1924. This is the first moniliformid acanthocephalan described from a wild rodent in Brazil.


Asunto(s)
Moniliformis/clasificación , Moniliformis/ultraestructura , Sigmodontinae/parasitología , Animales , Brasil , Femenino , Genes Mitocondriales/genética , Masculino , Microscopía Electrónica de Rastreo , Filogenia , ARN Ribosómico/genética
16.
Reproduction ; 158(1): 71-83, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31013477

RESUMEN

Beneficial effects of n-3 polyunsaturated fatty acid (PUFA) supplementation on dairy cow reproduction have been previously reported. The objectives of the present study were to assess whether n-3 PUFA supplementation would affect in vitro embryo production (IVP) after ovarian stimulation. Holstein cows received a diet with 1% dry matter supplementation of either n-3 PUFA (n = 18, microencapsulated fish oil) or a control, n-6 PUFA (n = 19, microencapsulated soy oil). Both plasma and follicular fluid FA composition showed integration of total PUFA through the diet. All cows underwent an IVP protocol consisting of ovarian stimulation, ultrasound-guided transvaginal oocyte retrieval (ovum pick-up, OPU, five per cow) followed by in vitro maturation, fertilisation and 7 days of embryo development. A tendency toward an increase in the blastocyst rate (diet effect, P = 0.0865) was observed in n-3 cows, with 49.6 ± 5.5% vs 42.3 ± 5.5% in control n-6 cows. A significant increase (diet effect, P = 0.0217) in the good-quality blastocyst rate (freezable blastocysts) was reported in n-3 cows (42.2 ± 7.7%) compared to control n-6 cows (32.7 ± 7.7%). A significant difference in lipid composition was shown in the oocytes recovered by OPU from n-3 and n-6 treated cows, by intact single-oocyte MALDI-TOF mass spectrometry. The 42 differentially abundant identified lipids were mainly involved in cell membrane structure. In conclusion, n-3 PUFA supplementation enhanced oocyte quality and modified their lipid composition. Further studies are necessary to investigate the potential link of these lipid modifications with enhanced oocyte quality.


Asunto(s)
Dieta/veterinaria , Suplementos Dietéticos , Embrión de Mamíferos/citología , Desarrollo Embrionario/efectos de los fármacos , Ácidos Grasos Omega-3/administración & dosificación , Oocitos/citología , Inducción de la Ovulación/veterinaria , Animales , Bovinos , Embrión de Mamíferos/efectos de los fármacos , Femenino , Fertilización In Vitro/veterinaria , Oocitos/efectos de los fármacos
18.
Exp Parasitol ; 197: 36-42, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30633915

RESUMEN

Molecules from natural sources, such as essential oils, have shown activity against parasites in vitro, but have not yet been explored extensively in vivo. Anethole and carvone (10% each), encapsulated with 80% of a solid matrix, referred to as EO (encapsulated oils), were tested in vivo in 2 experiments. In Experiment 1: Lambs were artificially infected with multidrug resistant Haemonchus contortus, or left uninfected, and treated (or not) with 50 mg/kg bw (body weight) of EO in a controlled environment. Thirty-two male lambs were kept in individual cages for a period of 45 days, after which animals were evaluated for parasitological, hematological, toxicological, and nutritional parameters. After 45 days of treatment, EO at 50 mg/kg bw provided a significant (P ≤ 0.05) reduction in fecal egg count (FEC). Although FEC was reduced, animals from both treatments had similar counts of total adult worms. The low FEC was caused probably by a significant reduction (P ≤ 0.05) in both male worm size and female fecundity. Dry matter intake of uninfected controls was significantly (P ≤ 0.05) reduced, although no toxicity was observed in treated animals. Thus, in Experiment 2, conducted for five months we used an EO dose of 20 mg/kg bw. Thirty-four weaned lambs, free of parasites, were divided in two groups and kept in collective pens. One group received EO at 20 mg/kg bw mixed with concentrate for 5 months and the other was kept as a control group (CTL). Parasitological and hematological parameters as well as body weight were evaluated. In the first 2.5 months, CTL and EO groups were confined, and both presented similar clinical parameters. Then, animals were allotted to graze on contaminated pastures to acquire natural infection for the next 2.5 months. The infection was patent after 25 days and both groups had similar decreases in weight gain, increases in FEC, and decreases in blood parameters. Coprocultures from CTL and EO groups established that parasite population was 90% Haemonchus sp. We concluded that the technology of encapsulation is safe and practical to deliver to lambs at the farm level and anethole and carvone at 50 mg/kg bw caused a significant decrease in FEC and, consequently, in pasture contamination by free living stages of H. contortus. However, EO at 20 mg/kg bw was not effective to prevent or treat sheep naturally-infected with gastrointestinal nematodes.


Asunto(s)
Anisoles/uso terapéutico , Hemoncosis/veterinaria , Monoterpenos/uso terapéutico , Enfermedades de las Ovejas/tratamiento farmacológico , Enfermedades de las Ovejas/parasitología , Abomaso/parasitología , Derivados de Alilbenceno , Animales , Anisoles/administración & dosificación , Anisoles/química , Aspartato Aminotransferasas/sangre , Cápsulas , Creatinina/sangre , Monoterpenos Ciclohexánicos , Resistencia a Múltiples Medicamentos , Sinergismo Farmacológico , Ingestión de Alimentos , Recuento de Eritrocitos/veterinaria , Heces/parasitología , Femenino , Fertilidad , Hemoncosis/tratamiento farmacológico , Hemoncosis/parasitología , Haemonchus/efectos de los fármacos , Haemonchus/crecimiento & desarrollo , Haemonchus/fisiología , Masculino , Monoterpenos/administración & dosificación , Monoterpenos/química , Recuento de Huevos de Parásitos/veterinaria , Distribución Aleatoria , Ovinos , Urea/sangre , Aumento de Peso , gamma-Glutamiltransferasa/sangre
19.
Int Endod J ; 52(12): 1679-1690, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31241779

RESUMEN

AIM: To evaluate in vivo the bone tissue response of rats to varying amounts of infected and noninfected dentine debris. METHODOLOGY: Bone tissue reactions were evaluated histologically in 42 Wistar rats after 7, 30 and 60 days. For each animal, three surgical cavities were prepared on the femur and filled with varying amounts (5, 10 or 20 mg) of infected or noninfected dentine debris pellets. In the negative control group, the surgical cavities were not filled. At the end of each experimental period, the animals were euthanized. The samples were processed histologically and analysed using a light microscope. The presence and the severity of inflammatory reaction, as well as hard tissue deposition were evaluated. Data were subjected to statistical analysis and the effects of the dependent variables calculated using nonparametric tests Kruskal-Wallis and Mann-Whitney U with due Bonferroni corrections at P = 0.05. RESULTS: At 7 days, the presence of infected debris significantly increased the histopathological scores for neutrophils (P < 0.05), and abscess formation (P < 0.05). Noninfected debris scored significantly higher for lymphocyte infiltrate compared with the control group and infected debris (P < 0.05). Both infected and noninfected debris equally triggered eosinophil cells compared with no-dentine (P < 0.05). As for giant cells and macrophages, no difference was detected amongst the dentine groups (P > 0.05). Hard tissue deposition was similar regardless of the presence or the bacteriological status of the dentine (P = 1.00). None of the above histopathological parameters was significantly influenced by the amount of debris (P > 0.05). For all parameters evaluated, at 7 days of analysis, the inflammatory response was significantly more intense compared with 30 and 60 days (P < 0.05). Inflammatory parameters were scored similarly for the evaluated groups after 30 and 60 days (P > 0.05). However, hard tissue deposition has significantly increased after 30 days (P < 0.05). No difference was seen between 30 and 60 days of analysis (P = 1.00) for all histological parameters evaluated. CONCLUSION: The assumption that the amount of extruded debris may negatively affect the inflammatory response of bone tissue was not validated in the present in vivo animal study. Infected dentine may trigger acute inflammatory parameters especially during the first 7 days of contact with the tissue; however, in the long term, these negative effects are mitigated.


Asunto(s)
Dentina , Ultrasonido , Animales , Humanos , Ratas , Ratas Wistar
20.
Int Endod J ; 52(10): 1446-1456, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31034099

RESUMEN

AIM: To evaluate bone tissue reactions in rats to an MTA-based endodontic sealer with and without the addition of various concentrations of C3A or C3A + Ag. METHODOLOGY: Bone tissue reactions were evaluated in 45 Wistar rats after 7, 30 and 90 days (n = 5 per period). Three surgical cavities were prepared on the right femur and filled with 0.2 mL MTA Fillapex, MTA Fillapex + C3A and C3A + Ag at various concentrations: AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany), EndoSequence BC (Brasseler USA, Savannah, GA, USA) or no sealer (negative control). By the end of each experimental period, animals were randomly euthanized. The samples were histologically processed and analysed using a light microscope. The presence of inflammatory cells, fibres and hard tissue barrier formation was evaluated. Data were analysed statistically using nonparametric tests to compare the differences between groups. Multiple groups were compared using the Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction at P = 0.05. RESULTS: The inflammatory response significantly decreased from 30 to 90 days (P < 0.05). Fibre condensation was similar amongst the groups at 07 and 30 days after intervention (P > 0.05). At 90 days, however, fibres were absent in most specimens of EndoSequence BC Sealer, AH Plus, MTA Fillapex and the control group, whilst they were still observed in samples of the modified sealers (P < 0.05). At 90 days, all specimens of AH Plus, EndoSequence BC Sealer and control group had complete formation of hard tissue barrier. In the MTA Fillapex group, as well as in the modified sealers groups, partial deposition of mineralized tissue was noticed. CONCLUSION: The hypothesis tested that the incorporation of C3A and C3A + Ag particles to MTA Fillapex would improve bone tissue repair was partially accepted, since modified MTA Fillapex did not have the same repair potential as the commercial bioceramic material.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Plata , Compuestos de Aluminio , Animales , Compuestos de Calcio , Combinación de Medicamentos , Resinas Epoxi , Alemania , Ensayo de Materiales , Óxidos , Pemetrexed , Ratas , Ratas Wistar , Silicatos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA