Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
J Parasitol ; 110(2): 150-154, 2024 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-38613824

RESUMEN

Freshwater snails are commonly studied within the context of their role as intermediate hosts for digenetic trematodes. However, there are fundamental data deficiencies related to our understanding of directly transmitted parasites, such as coccidia, for freshwater snails. Because variation in coccidia pathogenicity and transmission among snail species likely has major impacts on snail community structure, we aimed to investigate the spatial distribution and prevalence of coccidia in several freshwater snail species throughout the Ozark and Ouachita Mountains ecoregions in Arkansas. We opportunistically collected 220 freshwater snails from 24 Ozark sites in summer 2022 and scanned fecal slides for the presence of coccidia. In summer 2023, we surveyed an additional 146 snails from 19 Ouachita sites. To test for apparent interactions among coccidia and trematodes, we scanned feces from a subset of snails (Physa and Planorbella in the Ozarks) that did not have concurrent trematode infections and from those that did. We observed oocysts that morphologically conformed to Pfeifferinella ellipsoides in 2 of the 9 snail taxa from 7 of the 43 sites. Planorbella trivolvis was infected at 2 of 6 sites in the Ozarks and 0 of 5 sites in the Ouachitas. Physa species were infected at 6 of 14 sites in the Ozarks and 0 of 12 sites in the Ouachitas. In the Ozarks, Pl. trivolvis had an overall prevalence of 0.13 (6 of 47), whereas individuals in the genus Physa had an overall prevalence of 0.08 (8 of 97). Our chi-square and Fisher exact tests revealed no significant evidence for trematode-coccidia competition or synergism within the two snail species. There were no other species infected, and we did not observe any coccidia in the snails from the Ouachitas. Our survey of 366 snails among 9 taxa and 43 sites represents the largest survey for freshwater snail coccidia to date and indicates that both Pl. trivolvis and Physa spp. may be primary hosts and/or reservoir hosts for Pf. ellipsoides in freshwater snail communities. The highly aggregated distribution of Pf. ellipsoides in northwestern Arkansas requires further investigation. Our results led to proposal of several hypotheses for additional research, including questions regarding the variation of coccidia host specificity and virulence.


Asunto(s)
Coccidios , Caracoles , Humanos , Prevalencia , Arkansas , Agua Dulce
2.
Am J Pharm Educ ; 88(1): 100615, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37914030

RESUMEN

OBJECTIVES: This scoping review aimed to summarize the available literature on the use of artificial intelligence (AI) in pharmacy education and identify gaps where additional research is needed. FINDINGS: Seven studies specifically addressing the use of AI in pharmacy education were identified. Of these 7 studies, 5 focused on AI use in the context of teaching and learning, 1 on the prediction of academic performance for admissions, and the final study focused on using AI text generation to elucidate the benefits and limitations of ChatGPT use in pharmacy education. SUMMARY: There are currently a limited number of available publications that describe AI use in pharmacy education. Several challenges exist regarding the use of AI in pharmacy education, including the need for faculty expertise and time, limited generalizability of tools, limited outcomes data, and several legal and ethical concerns. As AI use increases and implementation becomes more standardized, opportunities will be created for the inclusion of AI in pharmacy education.


Asunto(s)
Rendimiento Académico , Educación en Farmacia , Humanos , Inteligencia Artificial , Docentes , Aprendizaje
3.
Electrophoresis ; 44(15-16): 1234-1246, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37431197

RESUMEN

Dielectrophoresis (DEP) is a successful method to recover nanoparticles from different types of fluid. The DEP force acting on these particles is created by an electrode microarray that produces a nonuniform electric field. To apply DEP to a highly conducting biological fluid, a protective hydrogel coating over the metal electrodes is required to create a barrier between the electrode and the fluid. This protects the electrodes, reduces the electrolysis of water, and allows the electric field to penetrate into the fluid sample. We observed that the protective hydrogel layer can separate from the electrode and form a closed domed structure and that collection of 100 nm polystyrene beads increased when this occurred. To better understand this collection increase, we used COMSOL Multiphysics software to model the electric field in the presence of the dome filled with different materials ranging from low-conducting gas to high conducting phosphate-buffered saline fluids. The results suggest that as the electrical conductivity of the material inside the dome is reduced, the whole dome acts as an insulator which increases electric field intensity at the electrode edge. This increased intensity widens the high-intensity electric field factor zone resulting in increased collection. This informs how dome formation results in increased particle collection and provides insight into how the electric field can be intensified to the increase collection of particles. These results have important applications for increasing the recovery of biologically-derived nanoparticles from undiluted physiological fluids that have high conductance, including the collection of cancer-derived extracellular vesicles from plasma for liquid biopsy applications.


Asunto(s)
Electricidad , Programas Informáticos , Electroforesis/métodos , Conductividad Eléctrica , Electrodos
4.
Am J Health Syst Pharm ; 80(11): 678-686, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-36857752

RESUMEN

PURPOSE: The purpose of this study was to validate the Stanford Professional Fulfillment Index (PFI) for assessment of burnout and professional fulfillment in a study population of pharmacy residents and residency preceptors. SUMMARY: The historical gold standard for assessing professional burnout is the Maslach Burnout Inventory (MBI); there is no established standard for professional fulfillment. The PFI is a 16-question assessment that has previously been validated in medical residents and practicing physicians. In this study, surveys including both PFI and MBI items were sent to active pharmacy residents and residency preceptors. To determine concurrent validity, domains of the PFI were compared to the closest related MBI domain as well as composite burnout rates measured in each portion of the survey. A total of 142 preceptors and 68 residents completed both the PFI and a version of the MBI previously validated in physicians. In assessing indicators of pharmacist burnout and fulfillment, data captured by domains of the PFI closely correlated with data captured by corresponding domains of the MBI (Pearson correlations of 0.683-0.822), with high internal consistency (Cronbach α of 0.866-0.903). CONCLUSION: The PFI is a valid method of assessing burnout in both pharmacy residents and residency preceptors. Additionally, the PFI contributes a reliable system of assessing professional fulfillment while also being highly accessible for both research and residency program monitoring applications.


Asunto(s)
Agotamiento Profesional , Farmacia , Médicos , Humanos , Encuestas y Cuestionarios , Agotamiento Psicológico , Agotamiento Profesional/diagnóstico , Agotamiento Profesional/epidemiología
5.
J Parasitol ; 108(5): 423-434, 2022 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-36197730

RESUMEN

The acanthocephalan Neoechinorhynchus emydis has a complex life cycle and infects turtle, ostracod, and snail hosts. However, little information is available on the seasonal distribution or the effects of N. emydis on freshwater snail hosts. To address this, we examined the seasonal distribution and melanization of acanthocephalans in Planorbella cf. Planorbella trivolvis snails from a single location in north-central Oklahoma. Seasonally, prevalence of N. emydis was 0% during the winter, increased to 50% during the summer, and declined to 17% in the fall. Mean abundance exhibited more variation but generally followed a similar pattern as prevalence. More important, all acanthocephalans located within the head/foot region of snail hosts contained melaninlike pigment surrounding each worm, suggesting that snails were mounting an immunological reaction to infections with N. emydis. Snail shell diameter was greatest during the fall and decreased during the winter, indicating that larger or older snails were dying during the winter. However, because field-collected snails were commonly infected with trematodes, and snail size varied significantly with season, it was unclear whether the observed seasonal dynamics of acanthocephalan infections were a result of snail mortality resulting from snail age, parasitic infections, or a combination of factors. To control for these factors, we exposed laboratory-reared Planorbella cf. P. trivolvis snails to naturally infected ostracods in field cages for 5-wk intervals during the winter, spring, and summer. Data from snail-cage infections were consistent with the seasonal field survey such that N. emydis infections were highest in the summer (20%) and lowest (0%) in the winter, suggesting that snails were not ingesting infected ostracods during the winter. However, fewer of our laboratory-reared snails survived in field cages during winter than during spring and summer, suggesting that snails may die more often during harsh winter conditions. Finally, we conducted a laboratory survival experiment by testing the life span and egg production of field-collected snails of various sizes that were naturally infected with acanthocephalans or trematodes or both. Our snail-survival experiment indicated that snail size but not infection status with acanthocephalans or trematodes affected snail survival, with larger snails surviving a shorter amount of time than smaller snails. In addition, snails infected with trematodes laid significantly fewer eggs compared with uninfected snails or snails infected with acanthocephalans. However, we found no significant difference in the number of eggs laid by acanthocephalan-infected and uninfected snails. Although other abiotic factors still need evaluation, we suggest that the occurrence of acanthocephalans in snails throughout the year may be partially influenced by the abundance of infected ostracods that snails may be ingesting and snail population fluctuations during the year.


Asunto(s)
Acantocéfalos , Trematodos , Animales , Crustáceos , Agua Dulce , Oklahoma/epidemiología , Estaciones del Año , Caracoles
6.
Electrophoresis ; 43(16-17): 1784-1798, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35753078

RESUMEN

Cancer is a highly heterogenous disease that requires precise detection tools and active surveillance methods. Liquid biopsy assays provide an agnostic way to follow the complex trajectory of cancer, providing better patient stratification tools for optimized treatment. Here, we present the development of a low-volume liquid biopsy assay called cyc-DEP (cyclic immunofluorescent imaging on dielectrophoretic chip) to profile biomarkers collected on a dielectrophoretic microfluidic chip platform. To enable on-chip cyclic imaging, we optimized a fluorophore quenching method and sequential rounds of on-chip staining with fluorescently conjugated primary antibodies. cyc-DEP allows for the quantification of a multiplex array of proteins using 25 µl of a patient plasma sample. We utilized nanoparticles from a prostate adenocarcinoma (LNCaP) cell line and a panel of six target proteins to develop our proof-of-concept technique. We then used cyc-DEP to quantify blood plasma levels of target proteins from healthy individuals, low-grade and high-grade prostate cancer patients (n = 3 each) in order to demonstrate that our platform is suitable for liquid biopsy analysis in its present form. To ensure accurate quantification of signal intensities and comparisons between different samples, we incorporated a signal intensity normalization method (fluorescent beads) and a custom signal intensity quantification algorithm that account for the distribution of signal across hundreds of collection regions on each chip. Our technique enabled a threefold improvement in multiplicity for detecting proteins associated with fluid samples, opening doors for early detection, and active surveillance through quantification of a multiplex array of biomarkers from low-volume liquid biopsies.


Asunto(s)
Bioensayo , Microfluídica , Electroforesis/métodos , Técnica del Anticuerpo Fluorescente , Humanos , Coloración y Etiquetado
7.
Evol Appl ; 15(2): 286-299, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35233248

RESUMEN

Urbanization is decreasing wildlife habitat and connectivity worldwide, including for apex predators, such as the puma (Puma concolor). Puma populations along California's central and southern coastal habitats have experienced rapid fragmentation from development, leading to calls for demographic and genetic management. To address urgent conservation genomic concerns, we used double-digest restriction-site associated DNA (ddRAD) sequencing to analyze 16,285 genome-wide single-nucleotide polymorphisms (SNPs) from 401 pumas sampled broadly across the state. Our analyses indicated support for 4-10 geographically nested, broad- to fine-scale genetic clusters. At the broadest scale, the four genetic clusters had high genetic diversity and exhibited low linkage disequilibrium, indicating that pumas have retained genomic diversity statewide. However, multiple lines of evidence indicated substructure, including 10 finer-scale genetic clusters, some of which exhibited fixed alleles and linkage disequilibrium. Fragmented populations along the Southern Coast and Central Coast had particularly low genetic diversity and strong linkage disequilibrium, indicating genetic drift and close inbreeding. Our results demonstrate that genetically at risk populations are typically nested within a broader-scale group of interconnected populations that collectively retain high genetic diversity and heterogenous fixations. Thus, extant variation at the broader scale has potential to restore diversity to local populations if management actions can enhance vital gene flow and recombine locally sequestered genetic diversity. These state- and genome-wide results are critically important for science-based conservation and management practices. Our nested population genomic analysis highlights the information that can be gained from population genomic studies aiming to provide guidance for the conservation of fragmented populations.

8.
Crit Care Explor ; 4(2): e0633, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35187497

RESUMEN

The response of ICU patients to continuously infused ketamine when it is used for analgesia and/or sedation remains poorly established. OBJECTIVES: To describe continuous infusion (CI) ketamine use in critically ill patients, including indications, dose and duration, adverse effects, patient outcomes, time in goal pain/sedation score range, exposure to analgesics/sedatives, and delirium. DESIGN SETTING AND PARTICIPANTS: Multicenter, retrospective, observational study from twenty-five diverse institutions in the United States. Patients receiving CI ketamine between January 2014 and December 2017. MAIN OUTCOMES AND MEASURES: Chart review evaluating institutional and patient demographics, ketamine indication, dose, administration, and adverse effects. Pain/sedation scores, cumulative doses of sedatives and analgesics, and delirium screenings in the 24 hours prior to ketamine were compared with those at 0-24 hours and 25-48 hours after. RESULTS: A total of 390 patients were included (median age, 54.5 yr; interquartile range, 39-65 yr; 61% males). Primary ICU types were medical (35.3%), surgical (23.3%), and trauma (17.7%). Most common indications were analgesia/sedation (n = 357, 91.5%). Starting doses were 0.2 mg/kg/hr (0.1-0.5 mg/kg/hr) and continued for 1.6 days (0.6-2.9 d). Hemodynamics in the first 4 hours after ketamine were variable (hypertension 24.0%, hypotension 23.5%, tachycardia 19.5%, bradycardia 2.3%); other adverse effects were minimal. Compared with 24 hours prior, there was a significant increase in proportion of time spent within goal pain score after ketamine initiation (24 hr prior: 68.9% [66.7-72.6%], 0-24 hr: 78.6% [74.3-82.5%], 25-48 hr: 80.3% [74.6-84.3%]; p < 0.001) and time spent within goal sedation score (24 hr prior: 57.1% [52.5-60.0%], 0-24 hr: 64.1% [60.7-67.2%], 25-48 hr: 68.9% [65.5-79.5%]; p < 0.001). There was also a significant reduction in IV morphine (mg) equivalents (24 hr prior: 120 [25-400], 0-24 hr: 118 [10-363], 25-48 hr: 80 [5-328]; p < 0.005), midazolam (mg) equivalents (24 hr prior: 11 [4-67], 0-24 hr: 6 [0-68], 25-48 hr: 3 [0-57]; p < 0.001), propofol (mg) (24 hr prior: 942 [223-4,018], 0-24 hr: 160 [0-2,776], 25-48 hr: 0 [0-1,859]; p < 0.001), and dexmedetomidine (µg) (24 hr prior: 1,025 [276-1,925], 0-24 hr: 285 [0-1,283], 25-48 hr: 0 [0-826]; p < 0.001). There was no difference in proportion of time spent positive for delirium (24 hr prior: 43.0% [17.0-47.0%], 0-24 hr: 39.5% [27.0-43.8%], 25-48 hr: 0% [0-43.7%]; p = 0.233). Limitations to these data include lack of a comparator group, potential for confounders and selection bias, and varying pain and sedation practices that may have changed since completion of the study. CONCLUSIONS AND RELEVANCE: There is variability in the use of CI ketamine. Hemodynamic instability was the most common adverse effect. In the 48 hours after ketamine initiation compared with the 24 hours prior, proportion of time spent in goal pain/sedation score range increased and exposure to other analgesics/sedatives decreased.

9.
Ground Water ; 60(1): 6-14, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34850384

RESUMEN

Groundwater professionals require tools to evaluate a variety of technical issues related to per- and polyfluoroalkyl substances (PFAS). These include the potential impact of PFAS precursors on groundwater plumes of perfluoroalkyl acids (PFAAs). Numerical modeling results show that, by adjusting the mass loading rate, source zones with or without a precursor can produce similar PFAA plumes. However, if a precursor is present, it can impact PFAA plume concentrations and extend PFAA plume durations by decades. Additional research regarding in situ precursor transformation rates-and improvements in source area characterization-will further advance the predictive value of modeling.


Asunto(s)
Fluorocarburos , Agua Subterránea , Contaminantes Químicos del Agua , Fluorocarburos/análisis , Contaminantes Químicos del Agua/análisis
10.
Pharmaceutics ; 15(1)2022 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-36678770

RESUMEN

Some cancer cells rely heavily on non-essential biomolecules for survival, growth, and proliferation. Enzyme based therapeutics can eliminate these biomolecules, thus specifically targeting neoplastic cells; however, enzyme therapeutics are susceptible to immune clearance, exhibit short half-lives, and require frequent administration. Encapsulation of therapeutic cargo within biocompatible and biodegradable poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) is a strategy for controlled release. Unfortunately, PLGA NPs exhibit burst release of cargo shortly after delivery or upon introduction to aqueous environments where they decompose via hydrolysis. Here, we show the generation of hybrid silica-coated PLGA (SiLGA) NPs as viable drug delivery vehicles exhibiting sub-200 nm diameters, a metastable Zeta potential, and high loading efficiency and content. Compared to uncoated PLGA NPs, SiLGA NPs offer greater retention of enzymatic activity and slow the burst release of cargo. Thus, SiLGA encapsulation of therapeutic enzymes, such as asparaginase, could reduce frequency of administration, increase half-life, and improve efficacy for patients with a range of diseases.

11.
Commun Biol ; 4(1): 1130, 2021 09 24.
Artículo en Inglés | MEDLINE | ID: mdl-34561533

RESUMEN

Cellular circulating biomarkers from the primary tumor such as circulating tumor cells (CTCs) and circulating hybrid cells (CHCs) have been described to harbor tumor-like phenotype and genotype. CHCs are present in higher numbers than CTCs supporting their translational potential. Methods for isolation of CHCs do not exist and are restricted to low-throughput, time consuming, and biased methodologies. We report the development of a label-free dielectrophoretic microfluidic platform facilitating enrichment of CHCs in a high-throughput and rapid fashion by depleting healthy peripheral blood mononuclear cells (PBMCs). We demonstrated up to 96.5% depletion of PBMCs resulting in 18.6-fold enrichment of cancer cells. In PBMCs from pancreatic adenocarcinoma patients, the platform enriched neoplastic cells identified by their KRAS mutant status using droplet digital PCR with one hour of processing. Enrichment was achieved in 75% of the clinical samples analyzed, establishing this approach as a promising way to non-invasively analyze tumor cells from patients.


Asunto(s)
Biomarcadores de Tumor/análisis , Dispositivos Laboratorio en un Chip/estadística & datos numéricos , Leucocitos Mononucleares/química , Oncología Médica/métodos , Células Neoplásicas Circulantes/química , Diseño de Equipo , Humanos , Células MCF-7
12.
Lab Chip ; 21(7): 1318-1332, 2021 04 07.
Artículo en Inglés | MEDLINE | ID: mdl-33877235

RESUMEN

Tumor-secreted exosomes and other extracellular vesicles (EVs) in circulation contain valuable biomarkers for early cancer detection and screening. We have previously demonstrated collection of cancer-derived nanoparticles (NPs) directly from whole blood and plasma with a chip-based technique that uses a microelectrode array to generate dielectrophoretic (DEP) forces. This technique enables direct recovery of NPs from whole blood and plasma. The biomarker payloads associated with collected particles can be detected and quantified with immunostaining. Accurately separating the fluorescence intensity of stained biomarkers from background (BG) levels becomes a challenge when analyzing the blood from early-stage cancer patients in which biomarker concentrations are low. To address this challenge, we developed two complementary techniques to standardize the quantification of fluorescently immunolabeled biomarkers collected and concentrated at predictable locations within microfluidic chips. The first technique was an automated algorithm for the quantitative analysis of fluorescence intensity at collection regions within the chip compared to levels at adjacent regions. The algorithm used predictable locations of particle collection within the chip geometry to differentiate regions of collection and BG. We successfully automated the identification and removal of optical artifacts from quantitative calculations. We demonstrated that the automated system performs nearly the same as a human user following a standard protocol for manual artifact removal with Pearson's r-values of 0.999 and 0.998 for two different biomarkers (n = 36 patients). We defined a usable dynamic range of fluorescence intensities corresponding to 1 to 2000 arbitrary units (a.u.). Fluorescence intensities within the dynamic range increased linearly with respect to exposure time and particle concentration. The second technique was the implementation of an internal standard to adjust levels of biomarker fluorescence based on the relative collection efficiency of the chip. Use of the internal standard reduced variability in measured biomarker levels due to differences in chip-to-chip collection efficiency, especially at low biomarker concentrations. The internal standard did not affect linear trends between fluorescence intensity and exposure time. Adjustments using the internal standard improved linear trends between fluorescence intensity and particle concentration. The optical quantification techniques described in this paper can be easily adapted for other lab-on-a-chip platforms that have predefined regions of biomarker or particle collection and that rely on fluorescence detection.


Asunto(s)
Exosomas , Vesículas Extracelulares , Humanos , Dispositivos Laboratorio en un Chip , Microfluídica , Plasma
13.
Am J Ther ; 29(1): e1-e17, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33021546

RESUMEN

BACKGROUND: The 2013 American College of Cardiology/American Heart Association cholesterol guidelines, which identified four groups of patients at risk for atherosclerotic cardiovascular disease events, departed from the target-based approach to managing cholesterol. The impact of these guidelines on high-intensity statin use across the United States is unclear. STUDY QUESTION: The primary objective was to evaluate the rate of high-intensity potential (HIP) statin use before and after the 2013 guidelines. The secondary objective was to identify predictors of HIP statin use within the study population. STUDY DESIGN: A national cross-sectional study was conducted using data from the National Ambulatory Medical Care Survey. Office visits involving patients aged 21-75 years where criteria for HIP statin therapy were met were included. Visits involving pregnant patients were excluded. MEASURES AND OUTCOMES: Prescribing trends of HIP statins were measured from National Ambulatory Medical Care Survey data before and after the 2013 guidelines. Multivariate logistic regression identified variables associated with prescribing HIP statins. RESULTS: A total of 48,884 visits were included, representing more than 940 million office visits nationally. HIP statins were listed in 9.5% and 16.5% of visits before and after 2013, respectively (odds ratio [OR] 1.88; 95% confidence interval [CI] 1.62-2.20). The strongest predictors of HIP statin use were antihypertensive use (OR 5.38, 95% CI 4.67-6.20), comorbid hyperlipidemia (OR 2.93, 95% CI 2.62-3.29), Black race (OR 0.63, 95% CI 0.49-0.81), and Hispanic ethnicity (OR 0.65, 95% CI 0.52-0.80). CONCLUSIONS: Prescribing rates for HIP statins increased after the release of the 2013 guidelines. The prescribing rates were lower than expected, especially in Black and Hispanic patients. These observations signify opportunities to improve the quality of care for patients who are at risk for atherosclerotic cardiovascular disease events in the United States.


Asunto(s)
Aterosclerosis , Enfermedades Cardiovasculares , Inhibidores de Hidroximetilglutaril-CoA Reductasas , American Heart Association , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/prevención & control , Colesterol , Estudios Transversales , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Estados Unidos/epidemiología
14.
Ecol Evol ; 10(19): 10687-10696, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33072289

RESUMEN

Jointly considering the ecology (e.g., habitat use) and genetics (e.g., population genetic structure and diversity) of a species can increase understanding of current conservation status and inform future management practices. Previous analyses indicate that mountain lion (Puma concolor) populations in California are genetically structured and exhibit extreme variation in population genetic diversity. Although human development may have fragmented gene flow, we hypothesized the quantity and quality of remaining habitat available would affect the genetic viability of each population. Our results indicate that area of suitable habitat, determined via a resource selection function derived using 843,500 location fixes from 263 radio-collared mountain lions, is strongly and positively associated with population genetic diversity and viability metrics, particularly with effective population size. Our results suggested that contiguous habitat of ≥10,000 km2 may be sufficient to alleviate the negative effects of genetic drift and inbreeding, allowing mountain lion populations to maintain suitable effective population sizes. Areas occupied by five of the nine geographic-genetic mountain lion populations in California fell below this habitat threshold, and two (Santa Monica Area and Santa Ana) of those five populations lack connectivity to nearby populations. Enhancing ecological conditions by protection of greater areas of suitable habitat and facilitating positive evolutionary processes by increasing connectivity (e.g., road-crossing structures) might promote persistence of small or isolated populations. The conservation status of suitable habitat also appeared to influence genetic diversity of populations. Thus, our results demonstrate that both the area and status (i.e., protected or unprotected) of suitable habitat influence the genetic viability of mountain lion populations.

15.
J Mammal ; 101(4): 1061-1071, 2020 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-33100929

RESUMEN

Preserving connectivity in the core of a species' range is crucial for long-term persistence. However, a combination of ecological characteristics, social behavior, and landscape features can reduce connectivity among wildlife populations and lead to genetic structure. Pronghorn (Antilocapra americana), for example, exhibit fluctuating herd dynamics and variable seasonal migration strategies, but GPS tracking studies show that landscape features such as highways impede their movements, leading to conflicting hypotheses about expected levels of genetic structure. Given that pronghorn populations declined significantly in the early 1900s, have only partially recovered, and are experiencing modern threats from landscape modification, conserving connectivity among populations is important for their long-term persistence in North America. To assess the genetic structure and diversity of pronghorn in the core of their range, we genotyped 4,949 genome-wide single-nucleotide polymorphisms and 11 microsatellites from 398 individuals throughout the state of Wyoming. We found no evidence of genetic subdivision and minimal evidence of isolation by distance despite a range that spans hundreds of kilometers, multiple mountain ranges, and three interstate highways. In addition, a rare variant analysis using putatively recent mutations found no genetic division between pronghorn on either side of a major highway corridor. Although we found no evidence that barriers to daily and seasonal movements of pronghorn impede gene flow, we suggest periodic monitoring of genetic structure and diversity as a part of management strategies to identify changes in connectivity.

16.
PLoS Comput Biol ; 16(3): e1007707, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32203520

RESUMEN

In order to monitor progress towards malaria elimination, it is crucial to be able to measure changes in spatio-temporal transmission. However, common metrics of malaria transmission such as parasite prevalence are under powered in elimination contexts. China has achieved major reductions in malaria incidence and is on track to eliminate, having reporting zero locally-acquired malaria cases in 2017 and 2018. Understanding the spatio-temporal pattern underlying this decline, especially the relationship between locally-acquired and imported cases, can inform efforts to maintain elimination and prevent re-emergence. This is particularly pertinent in Yunnan province, where the potential for local transmission is highest. Using a geo-located individual-level dataset of cases recorded in Yunnan province between 2011 and 2016, we introduce a novel Bayesian framework to model a latent diffusion process and estimate the joint likelihood of transmission between cases and the number of cases with unobserved sources of infection. This is used to estimate the case reproduction number, Rc. We use these estimates within spatio-temporal geostatistical models to map how transmission varied over time and space, estimate the timeline to elimination and the risk of resurgence. We estimate the mean Rc between 2011 and 2016 to be 0.171 (95% CI = 0.165, 0.178) for P. vivax cases and 0.089 (95% CI = 0.076, 0.103) for P. falciparum cases. From 2014 onwards, no cases were estimated to have a Rc value above one. An unobserved source of infection was estimated to be moderately likely (p>0.5) for 19/ 611 cases and high (p>0.8) for 2 cases, suggesting very high levels of case ascertainment. Our estimates suggest that, maintaining current intervention efforts, Yunnan is unlikely to experience sustained local transmission up to 2020. However, even with a mean of 0.005 projected up to 2020, locally-acquired cases are possible due to high levels of importation.


Asunto(s)
Monitoreo Epidemiológico , Malaria , China/epidemiología , Biología Computacional , Erradicación de la Enfermedad , Sistemas de Información Geográfica , Humanos , Malaria/epidemiología , Malaria/prevención & control , Malaria/transmisión , Análisis Espacio-Temporal
17.
J Wildl Dis ; 55(2): 316-324, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30628856

RESUMEN

The appearance of West Nile virus (WNV) coincided with declines in California, US bird populations beginning in 2004, and particularly affected corvid populations, including Yellow-billed Magpies ( Pica nutalli), an endemic species to California. Our objective was to determine if the timing of the WNV epidemic correlated with changes in the genetic diversity or population structure of magpies. We hypothesized the declines in magpie abundance from WNV would lead to genetic bottlenecks and reduced genetic diversity, but not to changes in population genetic structure. To test these hypotheses, we genetically typed magpie samples collected during the Dead Bird Survey before WNV arrived (2002-04), immediately after WNV arrived in late 2004 (2006-08), and several generations after the onset of the epidemic (2009-11). For each of these three time periods, we tested for genetic bottlenecks, estimated genetic heterozygosity, allelic richness, relatedness, effective population sizes, and genetic structure, with the use of 10 nuclear microsatellite loci. Although there was no evidence for spatial or temporal genetic structure, genetic-diversity estimates were similar or below estimates for endangered corvid species. Measures of genetic diversity were consistent across time periods. In contrast to our expectation, we detected a genetic bottleneck prior to the WNV epidemic, which may have coincided with severe drought conditions in California, increasing human population size in magpie range, and an estimated 33% decrease in population size. We found weak evidence to support a bottleneck after the introduction of WNV in California. Our results suggest the WNV epidemic did not have additional catastrophic effects on the neutral genetic diversity of P. nutalli in the sampled areas. However, because we detected lower heterozygosity in Yellow-billed Magpies than has been reported in closely related endangered species, this species is of conservation concern and should be monitored to detect further population declines or loss of genetic diversity.


Asunto(s)
Enfermedades de las Aves/virología , Epidemias , Variación Genética , Passeriformes/genética , Fiebre del Nilo Occidental/veterinaria , Animales , Enfermedades de las Aves/epidemiología , California/epidemiología , Fiebre del Nilo Occidental/virología
18.
Evol Appl ; 11(10): 1779-1790, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30459829

RESUMEN

Conservation genetic techniques and considerations of the evolutionary potential of a species are increasingly being applied to species conservation. For example, effective population size (N e) estimates are useful for determining the conservation status of species, yet accurate estimates of current N e remain difficult to obtain. The effective population size can contribute to setting federal delisting criteria, as was done for the southern sea otter (Enhydra lutris nereis). After being hunted to near extinction during the North Pacific fur trade, the southern sea otter has recovered over part of its former range, but remains at relatively low numbers, making it desirable to obtain accurate and consistent estimates of N e. Although theoretical papers have compared the validity of several methods, comparisons of estimators using empirical data in applied conservation settings are limited. We combined thirteen years of demographic and genetic data from 1,006 sea otters to assess multiple N e estimators, as well as temporal trends in genetic diversity and population genetic structure. Genetic diversity was low and did not increase over time. There was no evidence for distinct genetic units, but some evidence for genetic isolation by distance. In particular, estimates of N e based on demographic data were much larger than genetic estimates when computed for the entire range of the population, but were similar at smaller spatial scales. The discrepancy between estimates at large spatial scales could be driven by cryptic population structure and/or individual differences in reproductive success. We recommend the development of new delisting criteria for the southern sea otter. We advise the use of multiple estimates of N e for other wide-ranging species, species with overlapping generations, or with sex-biased dispersal, as well as the development of improved metrics of genetic assessments of populations.

19.
Sci Adv ; 4(9): eaat7828, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30214939

RESUMEN

High lethality rates associated with metastatic cancer highlight an urgent medical need for improved understanding of biologic mechanisms driving metastatic spread and identification of biomarkers predicting late-stage progression. Numerous neoplastic cell intrinsic and extrinsic mechanisms fuel tumor progression; however, mechanisms driving heterogeneity of neoplastic cells in solid tumors remain obscure. Increased mutational rates of neoplastic cells in stressed environments are implicated but cannot explain all aspects of tumor heterogeneity. We present evidence that fusion of neoplastic cells with leukocytes (for example, macrophages) contributes to tumor heterogeneity, resulting in cells exhibiting increased metastatic behavior. Fusion hybrids (cells harboring hematopoietic and epithelial properties) are readily detectible in cell culture and tumor-bearing mice. Further, hybrids enumerated in peripheral blood of human cancer patients correlate with disease stage and predict overall survival. This unique population of neoplastic cells provides a novel biomarker for tumor staging, as well as a potential therapeutic target for intervention.


Asunto(s)
Carcinoma Ductal Pancreático/patología , Células Neoplásicas Circulantes/patología , Neoplasias Pancreáticas/patología , Animales , Biomarcadores de Tumor/sangre , Carcinoma Ductal Pancreático/mortalidad , Fusión Celular , Línea Celular Tumoral , Supervivencia Celular , Células Epiteliales/patología , Femenino , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Células Híbridas , Cariotipificación , Macrófagos/patología , Masculino , Ratones Endogámicos C57BL , Ratones Transgénicos , Neoplasias Pancreáticas/mortalidad , Microambiente Tumoral , Ensayos Antitumor por Modelo de Xenoinjerto
20.
Evol Appl ; 11(5): 694-704, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29875811

RESUMEN

Domestication and breeding for human-desired morphological traits can reduce population genetic diversity via founder events and artificial selection, resulting in inbreeding depression and genetic disorders. The ferret (Mustela putorius furo) was domesticated from European polecats (M. putorius), transported to multiple continents, and has been artificially selected for several traits. The ferret is now a common pet, a laboratory model organism, and feral ferrets can impact native biodiversity. We hypothesized global ferret trade resulted in distinct international genetic clusters and that ferrets transported to other continents would have lower genetic diversity than ferrets from Europe because of extreme founder events and no hybridization with wild polecats or genetically diverse ferrets. To assess these hypotheses, we genotyped 765 ferrets at 31 microsatellites from 11 countries among the continents of North America, Europe, and Australia and estimated population structure and genetic diversity. Fifteen M. putorius were genotyped for comparison. Our study indicated ferrets exhibit geographically distinct clusters and highlights the low genetic variation in certain countries. Australian and North American clusters have the lowest genetic diversities and highest inbreeding metrics whereas the United Kingdom (UK) cluster exhibited intermediate genetic diversity. Non-UK European ferrets had high genetic diversity, possibly a result of introgression with wild polecats. Notably, Hungarian ferrets had the highest genetic diversity and Hungary is the only country sampled with two wild polecat species. Our research has broad social, economic, and biomedical importance. Ferret owners and veterinarians should be made aware of potential inbreeding depression. Breeders in North America and Australia would benefit by incorporating genetically diverse ferrets from mainland Europe. Laboratories using ferrets as biomedical organisms should consider diversifying their genetic stock and incorporating genetic information into bioassays. These results also have forensic applications for conserving the genetics of wild polecat species and for identifying and managing sources of feral ferrets causing ecosystem damage.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...