Aquatic mammal fossils in Latin America – a review of records, advances and challenges in research in the last 30 years

Records of aquatic mammal fossils (e.g. cetaceans, pinnipeds, sirenians, mustelids, and desmostylians) from Latin America (Mexico to Tierra del Fuego, including Antartica) span since the mid-1800s. Aquatic mammal fossils received little attention from the scientific community, with most of the first studies conducted by Northern Hemisphere researchers. Over the last 30 years, paleontological research in Latin America has increased considerably, with descriptions of several new species and revisions of published original records. The Latin American fossil record of marine mammals spans from the Eocene to the Pleistocene, with formations and specimens of global significance. All three main groups of cetaceans are represented in the continent (Archaeoceti, Mysticeti, and Odontoceti). Pinnipedia are represented by the families Otariidae and Phocidae, with records starting in the Middle Miocene. Both living families of Sirenia (Trichechidae and Dugongidae) are recorded. While less common, but still relevant, records of desmostylians and mustelids are known from Oligocene and Miocene deposits. This review provides a summary of the aquatic mammals known to date, with a special focus on the advances and developments of the last 30 years, since Cozzuol’s (1996) review of the South American fossil record. An up-to-date complete list of species based on the literature and unpublished data is also provided. The study also provides future directions for paleontological research in Latin America, and discusses the challenges and opportunities in the field, including the emergence of a strong new generation of Latin American researchers, many of whom are women. Keywords: Cetacea, Pinnipedia, Sirenia, Southern Hemispher

Análisis de la tolerancia al ruido de características basadas en dinámica no lineal sobre señales fonocardiográficas

Una propiedad muy deseable en sistemas de detección automática de patologías es la robustez ante el ruido, tal que su presencia no afecte notablemente la habilidad de detectar patologías. El presente trabajo estudia la capacidad discriminatoria que características de la dinámica no lineal, en particular, el Exponente de Hurst, el Máximo Exponente de Lyapunov y la Dimensión de Correlación, puedan proveer en la detección de soplos cardíacos usando señales fonocardiográficas contaminadas con diferentes niveles de ruido. A su vez se hacen comparaciones con características obtenidas a partir de representaciones tiempo frecuencia. Los resultados muestran la fortaleza de las características basadas en dinámica no lineal para tareas de clasificación de estados funcionales, aún sobre señales con altos niveles de ruido.A very desirable attribute in automatic pathology detection systems is noise robustness, such that the presence of noise should not significantly affect the ability to detect pathologies. This paper explores the discriminatory potential that nonlinear dynamic features, in particular, the Hurst exponent, the maximum Lyapunov exponent and correlation dimension, can provide in the detection of heart murmurs using phonocardiographic signals contaminated with different levels of noise. At the same time comparing with features obtained from time frequency representations. The results show the strength of features based on nonlinear dynamics for functional state classification tasks, even on signals with high noise levels

Catasetum (Orchidaceae: Catasetinae) en Colombia: lista actualizada

Colombia se considera uno de los países más ricos en orquídeas, a pesar de que ha sido poco estudiado en algunas bioregiones del país. Los registros del género Catasetum corresponden entre 29 a 31 especies, sin embargo, existe un sinnúmero de equivocaciones en la identidad taxonómica interespecífica, como en el uso de sus sinónimos. Por tal motivo, el objetivo del presente trabajo es conocer la diversidad de Catasetum en Colombia. De esta manera, se realizaron salidas de campo, revisión de colecciones, literatura y herbarios. En la lista actualizada se registran 38 especies, que incluyen especies poco conocidas y confundidas como C. dejeaniorum, C. aff. juruenense, C. mooeri, C. tenebrosum y los híbridos naturales como C. aff. × apolloi, C. × dunstervillei y C. × violascens. De las cinco especies endémicas, C. blepharochilum y C. tricorne, se conocen solo de espécimen tipo, y C. lucis es exclusivo de Santander y cultivado, para C. rectangulare y C. villegasii, se realizan comentarios taxonómicos. La Amazonía y los Andes concentran la mayor diversidad y, el Caribe es la zona menos explorada. Además se incluyen los caracteres diagnósticos, rangos altitudinales, relaciones geográficas y los sinónimos utilizados en el país para algunas especies con identidad taxonómica dudosa. También, se resalta la necesidad de realizar exploraciones en zonas de vacíos de colecta,  como el Atlántico y, el Amazonas, centro de diversidad del grupo, con la finalidad de establecer futuros planes de manejo y conservación

Effects of ezetimibe on markers of synthesis and absorption of cholesterol in high-risk patients with elevated C-reactive protein

AbstractAimsHigh-risk subjects with elevated C-reactive protein (CRP) are at high risk for cardiovascular events and frequently require potent statins or combined lipid-lowering therapy to achieve lipid targets and decrease inflammation. Our study aimed at evaluating the effects of three lipid-modifying therapies on LDL-cholesterol, CRP levels and markers of cholesterol absorption and synthesis.Main methodsA prospective intervention study was performed in high cardiovascular risk individuals receiving atorvastatin 10mg daily for four weeks. Those with CRP≥2.0mg/L were randomized to another four-week treatment period with atorvastatin 40mg, ezetimibe 10mg or the combination of atorvastatin 40mg / ezetimibe 10mg. Lipids, markers of cholesterol absorption (campesterol and β-sitosterol), and synthesis (desmosterol), as well as CRP were quantified at baseline and end of study.Key findingsOne hundred and twenty two individuals were included. Atorvastatin alone or combined with ezetimibe reduced both LDL-cholesterol and CRP (P<0.002 vs. baseline; Wilcoxon); ezetimibe did not modify CRP. Ezetimibe-based therapies reduced absorption markers and their ratios to cholesterol (P<0.0001 vs. baseline, for all; Wilcoxon), whereas atorvastatin alone increased campesterol/cholesterol and β-sitosterol/cholesterol ratios (P<0.05 vs. baseline; Wilcoxon). In addition, ezetimibe also increased desmosterol and desmosterol/cholesterol ratio (P<0.0001 vs. baseline; Wilcoxon).SignificanceThese results contribute to understanding the link between cellular cholesterol homeostasis, inflammation and lipid-modifying therapies. Our findings highlight the broader benefit of combined therapy with a potent statin and ezetimibe decreasing inflammation, and preventing increase in cholesterol biosynthesis, an effect not observed with ezetimibe alone

A system dynamics model to predict the human monocyte response to endotoxins

System dynamics is a powerful tool that allows modeling of complex and highly networked systems such as those found in the human immune system. We have developed a model that reproduces how the exposure of human monocytes to lipopolysaccharides (LPSs) induces an inflammatory state characterized by high production of tumor necrosis factor alpha (TNFα), which is rapidly modulated to enter into a tolerant state, known as endotoxin tolerance (ET). The model contains two subsystems with a total of six states, seven flows, two auxiliary variables, and 14 parameters that interact through six differential and nine algebraic equations. The parameters were estimated and optimized to obtain a model that fits the experimental data obtained from human monocytes treated with various LPS doses. In contrast to publications on other animal models, stimulation of human monocytes with super-low-dose LPSs did not alter the response to a second LPSs challenge, neither inducing ET, nor enhancing the inflammatory response. Moreover, the model confirms the low production of TNFα and increased levels of C-C motif ligand 2 when monocytes exhibit a tolerant state similar to that of patients with sepsis. At present, the model can help us better understand the ET response and might offer new insights on sepsis diagnostics and prognosis by examining the monocyte response to endotoxins in patients with sepsisThis work was supported by grants from the “Instituto de Salud Carlos III” (ISCiii), “Fondo de Investigación Sanitaria” (FIS), and Fondos FEDER (PI14/01234, PIE15/00065) to EL-C. EA work contract is supported by the Torres Quevedo program from “Ministerio de Economía y Competitividad” (SPTQ1300X006175XV0). VT work contract is supported by the “Ministerio de Economía y Competitividad” (PTA2013-8265-I

Acute effect of meal glycemic index and glycemic load on blood glucose and insulin responses in humans

OBJECTIVE: Foods with contrasting glycemic index when incorporated into a meal, are able to differentially modify glycemia and insulinemia. However, little is known about whether this is dependent on the size of the meal. The purposes of this study were: i) to determine if the differential impact on blood glucose and insulin responses induced by contrasting GI foods is similar when provided in meals of different sizes, and; ii) to determine the relationship between the total meal glycemic load and the observed serum glucose and insulin responses. METHODS: Twelve obese women (BMI 33.7 ± 2.4 kg/m(2)) were recruited. Subjects received 4 different meals in random order. Two meals had a low glycemic index (40–43%) and two had a high-glycemic index (86–91%). Both meal types were given as two meal sizes with energy supply corresponding to 23% and 49% of predicted basal metabolic rate. Thus, meals with three different glycemic loads (95, 45–48 and 22 g) were administered. Blood samples were taken before and after each meal to determine glucose, free-fatty acids, insulin and glucagon concentrations over a 5-h period. RESULTS: An almost 2-fold higher serum glucose and insulin incremental area under the curve (AUC) over 2 h for the high- versus low-glycemic index same sized meals was observed (p < 0.05), however, for the serum glucose response in small meals this was not significant (p = 0.38). Calculated meal glycemic load was associated with 2 and 5 h serum glucose (r = 0.58, p < 0.01) and insulin (r = 0.54, p < 0.01) incremental and total AUC. In fact, when comparing the two meals with similar glycemic load but differing carbohydrate amount and type, very similar serum glucose and insulin responses were found. No differences were observed for serum free-fatty acids and glucagon profile in response to meal glycemic index. CONCLUSION: This study showed that foods of contrasting glycemic index induced a proportionally comparable difference in serum insulin response when provided in both small and large meals. The same was true for the serum glucose response but only in large meals. Glycemic load was useful in predicting the acute impact on blood glucose and insulin responses within the context of mixed meals

Depredación de Lithobates psilonota (Anura: Ranidae) por Leptodeira splendida bressoni (Squamata: Colubridae) en arroyos del área natural protegida Sierra de Quila, Jalisco, México

Photographic evidence shows the first record of predation in Mexico of Lithobates psilonota by Leptodeira splendida bressoni in the natural protected area Sierra de Quila, Jalisco

Cellular and humoral functional responses after BNT162b2 mRNA vaccination differ longitudinally between naive and subjects recovered from COVID-19

We have analyzed BNT162b2 vaccine-induced immune responses in naive subjects and individuals recovered from coronavirus disease 2019 (COVID-19), both soon after (14 days) and later after (almost 8 months) vaccination. Plasma spike (S)-specific immunoglobulins peak after one vaccine shot in individuals recovered from COVID-19, while a second dose is needed in naive subjects, although the latter group shows reduced levels all along the analyzed period. Despite how the neutralization capacity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mirrors this behavior early after vaccination, both groups show comparable neutralizing antibodies and S-specific B cell levels late post-vaccination. When studying cellular responses, naive individuals exhibit higher SARS-CoV-2-specific cytokine production, CD4+ T cell activation, and proliferation than do individuals recovered from COVID-19, with patent inverse correlations between humoral and cellular variables early post-vaccination. However, almost 8 months post-vaccination, SARS-CoV-2-specific responses are comparable between both groups. Our data indicate that a previous history of COVID-19 differentially determines the functional T and B cell-mediated responses to BNT162b2 vaccination over time.C.d.F., J.G.-P., and J.A. are supported by Instituto de Salud Carlos III (ISCII). We thank JM Ligos and Cytek Biosciences for their technical support. Research in E.L.-C.’s lab was supported by Fundación Familia Alonso, Santander Bank, Real Seguros, Fundación Mutua Madrileña, Fundación Uria, Fundación La Caixa, and Ayuntamiento de Madrid.S