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1.
Proc Biol Sci ; 290(1990): 20222181, 2023 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-36629105

RESUMEN

The timing of life events (phenology) can be influenced by climate. Studies from around the world tell us that climate cues and species' responses can vary greatly. If variation in climate effects on phenology is strong within a single ecosystem, climate change could lead to ecological disruption, but detailed data from diverse taxa within a single ecosystem are rare. We collated first sighting and median activity within a high-elevation environment for plants, insects, birds, mammals and an amphibian across 45 years (1975-2020). We related 10 812 phenological events to climate data to determine the relative importance of climate effects on species' phenologies. We demonstrate significant variation in climate-phenology linkage across taxa in a single ecosystem. Both current and prior climate predicted changes in phenology. Taxa responded to some cues similarly, such as snowmelt date and spring temperatures; other cues affected phenology differently. For example, prior summer precipitation had no effect on most plants, delayed first activity of some insects, but advanced activity of the amphibian, some mammals, and birds. Comparing phenological responses of taxa at a single location, we find that important cues often differ among taxa, suggesting that changes to climate may disrupt synchrony of timing among taxa.


Asunto(s)
Ecosistema , Insectos , Animales , Cambio Climático , Estaciones del Año , Temperatura , Aves , Mamíferos
2.
Dis Colon Rectum ; 66(4): 598-608, 2023 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35507740

RESUMEN

BACKGROUND: Rectourethral fistulas are a rare yet severe complication of prostate surgery, pelvic irradiation therapy, or both. Multiple surgical repairs exist with widely varying success rates. OBJECTIVE: This study aimed to present our institutional multidisciplinary algorithm for rectourethral fistula repair and its outcomes. DESIGN: This was a retrospective, pre- and postintervention, quasi-experimental design, comparing the frequency of fistula healing and reversal of urinary and fecal diversion before and after implementation of our algorithm. SETTING: All patients who presented to the Duke University with rectourethral fistula between 2002 and 2019 were included. PATIENTS: This study included 79 patients treated for rectourethral fistula: 36 prealgorithm and 43 postalgorithm. INTERVENTIONS: Our multidisciplinary algorithm was implemented in 2012. Patients with fistulas <2 cm and without history of radiation therapy underwent York-Mason repair, whereas those with fistulas 2-3 cm or with prior irradiation underwent transperineal repair with gracilis flap interposition. Those with nonrepairable fistulas (>3 cm or fixed tissues) underwent pelvic exenteration. Before repair, the algorithm recommended all patients to undergo urinary and bowel diversion. MAIN OUTCOME MEASURES: The 2 primary outcomes were rectourethral fistula healing, defined as both radiographic and clinical resolutions, and reversal of urinary and fecal diversions. RESULTS: Frequency of fistula healing improved in the post- versus prealgorithm subgroups (93.1% vs 71.9%; p = 0.04). The relative risk of fistula healing pre- versus postintervention was 0.77 (0.61-0.98; p = 0.04) among the overall cohort. Eighteen patients (22.8%) underwent pelvic exenteration for nonrepairable fistulas and were not included in primary outcome measures. LIMITATIONS: Limitations include the study's retrospective nature, possible selection bias because of algorithmic patient selection, and small sample size. CONCLUSIONS: Implementation of a multidisciplinary institutional algorithm improved rectourethral fistula repair success with high rates of ostomy reversal. Proper patient selection and multidisciplinary involvement are paramount to this success. See Video Abstract at http://links.lww.com/DCR/B955 . RESULTADOS DE UN ABORDAJE ALGORTMICO Y MULTIDISCIPLINARIO PARA LA REPARACIN DE FSTULAS RECTOURETRALES UN ESTUDIO CUASIEXPERIMENTAL PREVIO Y POSTERIOR A LA INTERVENCIN: ANTECEDENTES:Las fístulas rectouretrales son una complicación rara pero grave de la cirugía de próstata, la radiación pélvica o ambas. Existen múltiples reparaciones quirúrgicas con tasas de éxito muy variables.OBJETIVO:Presentar el algoritmo multidisciplinario de nuestra institución para la reparación de fístulas rectouretrales y sus resultados.DISEÑO:Este fue un diseño retrospectivo, previo y posterior a la intervención, cuasiexperimental, que comparó la frecuencia de curación de la fístula y la reversión de la derivación urinaria y fecal antes y después de la implementación de nuestro algoritmo.ESCENARIO:Se incluyeron todos los pacientes que acudieron a Duke con fístula rectouretral entre 2002 y 2019.PACIENTES:Setenta y nueve pacientes fueron tratados por fístula rectouretral; 36 pre-algoritmo y 43 post-algoritmo.INTERVENCIONES:Nuestro algoritmo multidisciplinario se implementó en 2012. Los pacientes con fístulas <2 cm y sin antecedentes de radiación se sometieron a reparación de York-Mason, mientras que aquellos con fístulas de 2-3 cm o radiación pélvica previa se sometieron a reparación transperineal con interposición de colgajo de gracilis. Aquellos con fístulas no reparables (> 3 cm o tejidos fijos) fueron sometidos a exenteración pélvica. Antes de la reparación, el algoritmo recomomendó que todos los pacientes se sometieran a una derivación urinaria y fecal.PRINCIPALES MEDIDAS DE RESULTADO:Los dos resultados primarios fueron la curación de la fístula rectouretral, definida como la resolución radiográfica y clínica, y la reversión de las derivaciones urinaria y fecale.RESULTADOS:La frecuencia de curación de la fístula mejoró en el subgrupo post-algoritmo vs. pre-algoritmo (93.1% vs. 71.9%, p = 0.04). El riesgo relativo de curación de la fístula antes de la intervención en comparación con después de la intervención fue de 0.77 (0.61-0.98, p = 0.04) entre la cohorte general. Dieciocho pacientes (22.8%) se sometieron a exenteración pélvica por fístulas no reparables y, por lo tanto, no se incluyeron en las medidas de resultado primarias.LIMITACIONES:Las limitaciones de este estudio incluyen su naturaleza retrospectiva, posible sesgo de selección debido a la selección algorítmica de pacientes y un tamaño de muestra pequeño.CONCLUSIONES:La implementación de un algoritmo institucional multidisciplinario mejoró el éxito en la reparación de la fístula rectouretral con altas tasas de reversión de la ostomía. La selección adecuada de pacientes y la participación multidisciplinaria son fundamentales para este éxito. Consulte Video Resumen en http://links.lww.com/DCR/B955 . (Traducción-Dr. Jorge Silva Velazco ).


Asunto(s)
Exenteración Pélvica , Fístula Rectal , Fístula Urinaria , Masculino , Humanos , Estudios Retrospectivos , Fístula Rectal/cirugía , Pelvis , Fístula Urinaria/etiología , Fístula Urinaria/cirugía
3.
Neurourol Urodyn ; 40(4): 1056-1062, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33811366

RESUMEN

AIMS: The artificial urinary sphincter (AUS), the gold standard for treatment of male stress urinary incontinence, can be filled with normal saline (NS) or isotonic contrast solution. Surgeons have voiced concerns about the impact on device malfunction and longevity, but no studies address this issue. We used industry data to identify differences in outcomes between NS and contrast-filled AUS. METHODS: Our analysis included all men patients in the industry who maintained the AUS database (Boston Scientific) from 2001 to 2016. Patients were divided into two groups: AUS filled with NS or contrast. Patient demographics and device characteristics were compared. Device survival was defined as time to the need for reoperation. We compared device survival between AUS filled with NS versus contrast using a Kaplan-Meier curve adjusted for age, cuff size, and pressure regulating balloon (PRB) size. RESULTS: A total of 39,363 patients were included. 34,674 (88.1%) devices were filled with NS. The reoperation rate overall was 24.5%, with no difference between groups. The mean time to reoperation overall was 3 years (±3.0). After adjustment for age, cuff size, and PRB size, Kaplan-Meier analysis demonstrated a similar time to reoperation between the two groups. CONCLUSION: The use of contrast in the AUS does not appear to change rates of the device malfunction, fluid loss, or need for reoperation. Since filling the device with contrast does not appear inferior to saline in terms of longevity, we feel this should be considered a safe tool for the implanting surgeon.


Asunto(s)
Incontinencia Urinaria de Esfuerzo , Esfínter Urinario Artificial , Humanos , Longevidad , Masculino , Reoperación , Estudios Retrospectivos , Resultado del Tratamiento , Incontinencia Urinaria de Esfuerzo/cirugía
4.
Int Braz J Urol ; 47(6): 1131-1135, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33861057

RESUMEN

Urethral slings are a good treatment option for mild male stress urinary incontinence. There are many different sling options, but herein our group describes our techniques with the Advance® and Virtue® slings. More important than technique, we strongly think that patient selection is paramount to sling success. We only offer slings to patients who have low 24 hour pad weights, high Valsalva leak point pressure, and no history of pelvic radiation. Still, like with any surgery, we recommend that the surgeons implant the device that they are most comfortable with along with their chosen techniques.


Asunto(s)
Cabestrillo Suburetral , Cirujanos , Incontinencia Urinaria de Esfuerzo , Humanos , Masculino , Prostatectomía , Resultado del Tratamiento , Incontinencia Urinaria de Esfuerzo/cirugía
5.
Ecol Lett ; 23(11): 1589-1598, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32812695

RESUMEN

Climate change is shifting the environmental cues that determine the phenology of interacting species. Plant-pollinator systems may be susceptible to temporal mismatch if bees and flowering plants differ in their phenological responses to warming temperatures. While the cues that trigger flowering are well-understood, little is known about what determines bee phenology. Using generalised additive models, we analyzed time-series data representing 67 bee species collected over 9 years in the Colorado Rocky Mountains to perform the first community-wide quantification of the drivers of bee phenology. Bee emergence was sensitive to climatic variation, advancing with earlier snowmelt timing, whereas later phenophases were best explained by functional traits including overwintering stage and nest location. Comparison of these findings to a long-term flower study showed that bee phenology is less sensitive than flower phenology to climatic variation, indicating potential for reduced synchrony of flowers and pollinators under climate change.


Asunto(s)
Cambio Climático , Flores , Animales , Abejas , Colorado , Estaciones del Año , Temperatura
6.
Neurourol Urodyn ; 39(5): 1538-1542, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32449543

RESUMEN

AIMS: Measuring the urethral circumference accurately during artificial urethral sphincter (AUS) placement is an important technical aspect to optimize the selection of cuff size. Differing methods exist for this step with some experts recommending measurement with no urethral catheter in place. In this prospective observational trial, we compared urethral measurements with and without an indwelling catheter to determine if the presence of a catheter affects the circumferential measurement. METHODS: With IRB approval, we prospectively collected data on consecutive cases of transperineal male AUS implantation. Urethral circumference was measured with no urethral catheter (0 French [Fr]), 12Fr, and 16Fr Foley catheters in the urethra. The final measurements and cuff size chosen were recorded. A comparison was made between each measurement using Spearman's correlation coefficient. RESULTS: A total of 54 patients were included, the majority of whom (92.6%) underwent AUS placement for postprostatectomy incontinence. The three urethral circumference measurements were highly correlated (0Fr vs 12Fr, ρ = 0.96, P < .001, mean difference 1 mm) (0Fr vs 16Fr, ρ = 0.94, P < .001, mean difference 2 mm) (12Fr vs 16Fr, ρ = 0.96, P < .001, mean difference 1 mm). Patients with a history of radiation had a lower mean urethral circumference than those who had never been radiated (4.78 cm vs 5.3 cm, P = .01). CONCLUSIONS: Urethral circumference measurement during AUS implantation is not influenced by the presence of a 12 or 16Fr Foley catheter when compared to no catheter in the urethra. Measurement of the urethral circumference can, therefore, be accurately performed with or without a catheter in place, depending on the surgeon's preference.


Asunto(s)
Uretra/cirugía , Cateterismo Urinario , Catéteres Urinarios , Incontinencia Urinaria/cirugía , Esfínter Urinario Artificial , Anciano , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Prostatectomía/efectos adversos , Prostatectomía/métodos , Reoperación , Vejiga Urinaria , Incontinencia Urinaria/etiología
7.
Oecologia ; 193(2): 261-271, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32281030

RESUMEN

For some animals, the habitat which they first experience can influence the type of habitat which they select later in life and, thus, potentially their population distribution and dynamics. However, for many insect herbivores, whose natal habitat may consist of a single hostplant, the consequences of natal hostplant experience remain untested in landscapes relevant to the adult, which may select not only among plants, but among plant patches. As a first step towards understanding how natal hostplant experience shapes patterns of insect feeding damage in landscapes relevant to adults, we conducted partially caged field experiments with diamondback moths that were reared on either mustard or collard plants and then allowed to choose among and within patches of plants that varied in plant density and composition. We predicted that natal hostplant experience would interact with patch size and composition to influence the number of diamondback moth offspring and feeding damage per plant. As predicted, when moths were reared on collards, we found more offspring on and damage to collard plants in four-collard patches than in two-collard patches (i.e., resource concentration), but no difference when moths were reared on mustards. Contrary to predictions, we found no difference in the number of offspring on or damage to mixed plant patches compared with two- or four-collard plant patches regardless of natal hostplant type. Our research suggests that prior hostplant experience has complex consequences for how insects and their feeding damage are distributed in patchy environments and highlights the need for future research in this area.


Asunto(s)
Mariposas Nocturnas , Animales , Ecosistema , Herbivoria , Larva , Planta de la Mostaza
8.
J Urol ; 210(6): 872-873, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37769611
9.
Neurourol Urodyn ; 37(3): 952-959, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-28984997

RESUMEN

AIMS: Denervation of the bladder is a detrimental consequence of bladder outlet obstruction (BOO). We have previously shown that, during BOO, inflammation triggered by the NLRP3 inflammasome in the urothelia mediates physiological bladder dysfunction and downstream fibrosis in rats. The aim of this study was to assess the effect of NLRP3-mediated inflammation on bladder denervation during BOO. METHODS: There were five groups of rats: (i) Control (no surgery); (ii) Sham-operated; (iii) BOO rats given vehicle; (iv) BOO rats given the NLRP3 inhibitor glyburide; and (v) BOO rats given the IL-1 receptor antagonist anakinra. BOO was constructed by ligating the urethra over a 1 mm catheter and removing the catheter. Medications were given prior to surgery and once daily for 12 days. Bladder sections were stained for PGP9.5, a pan-neuronal marker. Whole transverse sections were used to identify and count nerves while assessing cross-sectional area. For in vitro studies, pelvic ganglion neurons were isolated and treated with IL-1ß. After a 48 h incubation apoptosis, neurite length and branching were assessed. RESULTS: In obstructed bladders, the number of nerves decreased while total area increased, indicating a loss of cell number and/or branching. The decrease in nerve density was blocked by glyburide or anakinra, clearly implicating the NLRP3 pathway in denervation. In vitro analysis demonstrated that IL-1ß, a product of the inflammasome, induced apoptosis in pelvic ganglion neurons, suggesting one mechanism of BOO-induced denervation is NLRP3/IL-1ß triggered apoptosis. CONCLUSIONS: The NLRP3/IL-1ß-mediated inflammation pathway plays a significant role in denervation during BOO.


Asunto(s)
Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Obstrucción del Cuello de la Vejiga Urinaria/metabolismo , Vejiga Urinaria/inervación , Animales , Apoptosis/fisiología , Desnervación , Femenino , Inflamación/metabolismo , Inflamación/fisiopatología , Interleucina-1beta/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/fisiología , Uretra/metabolismo , Uretra/fisiopatología , Vejiga Urinaria/metabolismo , Vejiga Urinaria/fisiopatología , Obstrucción del Cuello de la Vejiga Urinaria/fisiopatología , Urotelio/metabolismo , Urotelio/fisiopatología
10.
Ecol Lett ; 20(12): 1507-1515, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29124863

RESUMEN

Climate change can influence consumer populations both directly, by affecting survival and reproduction, and indirectly, by altering resources. However, little is known about the relative importance of direct and indirect effects, particularly for species important to ecosystem functioning, like pollinators. We used structural equation modelling to test the importance of direct and indirect (via floral resources) climate effects on the interannual abundance of three subalpine bumble bee species. In addition, we used long-term data to examine how climate and floral resources have changed over time. Over 8 years, bee abundances were driven primarily by the indirect effects of climate on the temporal distribution of floral resources. Over 43 years, aspects of floral phenology changed in ways that indicate species-specific effects on bees. Our study suggests that climate-driven alterations in floral resource phenology can play a critical role in governing bee population responses to global change.


Asunto(s)
Abejas , Cambio Climático , Ecosistema , Animales , Reproducción , Especificidad de la Especie
12.
Ecology ; 98(11): 2904-2913, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28869769

RESUMEN

An individual's susceptibility to attack can be influenced by conspecific and heterospecifics neighbors. Predicting how these neighborhood effects contribute to population-level processes such as competition and evolution requires an understanding of how the strength of neighborhood effects is modified by changes in the abundances of both consumers and neighboring resource species. We show for the first time that consumer density can interact with the density and frequency of neighboring organisms to determine the magnitude of neighborhood effects. We used the bean beetle, Callosobruchus maculatus, and two of its host beans, Vigna unguiculata and V. radiata, to perform a response-surface experiment with a range of resource densities and three consumer densities. At low beetle density, damage to beans was reduced with increasing conspecific density (i.e., resource dilution) and damage to the less preferred host, V. unguiculata, was reduced with increasing V. radiata frequency (i.e., frequency-dependent associational resistance). As beetle density increased, however, neighborhood effects were reduced; at the highest beetle densities neither focal nor neighboring resource density nor frequency influenced damage. These findings illustrate the importance of consumer density in mediating indirect effects among resources, and suggest that accounting for consumer density may improve our ability to predict population-level outcomes of neighborhood effects and our use of them in applications such as mixed-crop pest management.


Asunto(s)
Ecosistema , Animales , Escarabajos , Fabaceae , Modelos Teóricos , Densidad de Población
13.
J Anim Ecol ; 86(5): 1065-1073, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28481414

RESUMEN

Disturbances are widespread in nature and can have substantial population-level consequences. Most empirical studies on the effects of disturbance track population recovery within habitat patches, but have an incomplete representation of the recolonization process. In addition, recent metapopulation models represent post-disturbance colonization with a recovery state or time-lag for disturbed ("focal") patches, thus assuming that recolonization rates are uniform. However, the availability of colonists in neighbouring "source" patches can vary, especially in frequently disturbed landscapes such as fire-managed forests that have a mosaic of patches that differ in successional state and undergo frequent local extinctions. To determine how time since disturbance in both focal and neighbouring source patches might affect metapopulations, we studied the effects of time since fire (TSF) on abundances of a specialist palmetto beetle within and between fire management units in Apalachicola National Forest, Florida. We measured beetle abundances at three distances from the shared edge of paired units, with units ranging from 0 to 64 months since fire and the difference in time since burning for a focal-source pair ranging from 3 to 58 months. Soon after fire, beetle abundances within management units were highest near the unit edge, but this pattern changed with increasing TSF. Between paired units, the more recently disturbed ("focal") unit's beetle abundance was positively related to source unit abundance, but the shape of this relationship differed based on focal unit TSF and the units' difference in time since burning. Results suggest that both focal and source habitat history can influence recolonization of recently disturbed patches and that these effects may persist over years. Thus, when predicting metapopulation dynamics, variation in habitat characteristics should be considered not only for patches receiving colonists but for patches supplying colonists as well.


Asunto(s)
Escarabajos , Ecosistema , Incendios , Animales , Florida , Dinámica Poblacional
14.
Electrophoresis ; 37(14): 2054-62, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27129779

RESUMEN

An assessment of fractionated mouse hippocampal peptides was conducted. Protein extract from a single mouse hippocampus was enzymatically digested and fractionated by IEF. Aliquots of fractions were pooled into fewer, more complex samples. The unfractionated lysate, fractions, and pooled fractions were subjected to LC-MS/MS analysis. Samples consisting of many individual fractions had more protein identifications, greater protein sequence coverage, and quantified proteins with more spectral counts than protein extract that was unfractionated or pooled into fewer LC-MS/MS samples. Additionally, prefractionation reduced the median CV for spectral counts as much as 33%. However, the relative gain in proteome resolution was found to saturate with increasing fractionation extent. This study demonstrates how prefractionation by offline IEF can improve the resolution of proteomic investigations of the mouse hippocampus, and that a data-driven pooling methodology can reduce excessive and cost-ineffective fractionation.


Asunto(s)
Cromatografía Liquida/métodos , Focalización Isoeléctrica/métodos , Proteoma , Espectrometría de Masas en Tándem/métodos , Animales , Ratones , Ratones Endogámicos C57BL
15.
Ecol Lett ; 18(2): 164-73, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25534277

RESUMEN

Predators can influence primary producers by generating cascades of effects in ecological webs. These effects are often non-intuitive, going undetected because they involve many links and different types of species interactions. Particularly, little is understood about how antagonistic (negative) and mutualistic (positive) interactions combine to create cascades. Here, we show that black bears can benefit plants by consuming ants. The ants are mutualists of herbivores and protect herbivores from other arthropod predators. We found that plants near bear-damaged ant nests had greater reproduction than those near undamaged nests, due to weaker ant protection for herbivores, which allowed herbivore suppression by arthropod predators. Our results highlight the need to integrate mutualisms into trophic cascade theory, which is based primarily on antagonistic relationships. Predators are often conservation targets, and our results suggest that bears and other predators should be managed with the understanding that they can influence primary producers through many paths.


Asunto(s)
Hormigas/fisiología , Cadena Alimentaria , Ursidae/fisiología , Animales , Artrópodos/fisiología , Herbivoria , Dinámica Poblacional , Conducta Predatoria
16.
J Urol ; 194(4): 1091-5, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25916676

RESUMEN

PURPOSE: Complete male epispadias is a rare congenital anomaly characterized by failed closure of the entire penopubic dorsal urethra. Epispadias repair is typically performed during infancy, and resultant genitourinary abnormalities can have a marked impact on adult life. We assess long-term post-reconstruction sexual health and fertility outcomes in adults with complete male epispadias. MATERIALS AND METHODS: A total of 132 patients 18 years or older with complete male epispadias who had undergone reconstruction were identified from a prospectively maintained, institutionally approved database. Patients who could be contacted were asked to complete a telephone survey regarding sexual function. Reconstructive history and clinical details were obtained by chart/database review. RESULTS: Of 132 patients with complete male epispadias 74 met inclusion criteria and 15 (20%) completed the questionnaire. Seven patients (47%) reported currently being in a relationship. Although 12 patients (80%) reported overall satisfactory sexual intercourse, 11 (73%) admitted to 1 or more problems with sexual function, including abnormal ejaculation (53%), diminished sensation (20%) and difficulty maintaining an erection (20%). When questioned regarding the importance of fertility on a scale of 0 to 5 using a Likert-type item the response of 10 patients (67%) was 4 points or greater. Five patients (33%) reported having impregnated a sexual partner. Although 4 patients (27%) had suspicion of fertility problems, only 2 (13%) reported having abnormal semen analyses. CONCLUSIONS: This is one of few studies examining post-reconstruction sexual health and function in adults with complete male epispadias. Although small, our study demonstrates that patients are able to engage in relationships, participate in sexual intercourse and impregnate their partners. These results highlight sexual concerns and outcomes that may be of use when counselling patients with complete male epispadias and their families.


Asunto(s)
Epispadias/cirugía , Salud Reproductiva , Adulto , Fertilidad , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Procedimientos Quirúrgicos Urológicos Masculinos , Adulto Joven
17.
Ecology ; 96(1): 264-73, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26236911

RESUMEN

A persistent challenge for ecologists is understanding the ecological mechanisms that maintain global patterns of biodiversity, particularly the latitudinal diversity gradient of peak species richness in the tropics. Spatial and temporal variation in community composition contribute to these patterns of biodiversity, but how this variation and its underlying processes change across latitude remains unresolved. Using a model system of sessile marine invertebrates across 25 degrees of latitude, from the temperate zone to the tropics, we tested the prediction that spatial and temporal patterns of taxonomic richness and composition, and the community assembly processes underlying these patterns, will differ across latitude. Specifically, we predicted that high beta diversity (spatial variation in composition) and high temporal turnover contribute to the high species richness of the tropics. Using a standardized experimental approach that controls for several confounding factors that hinder interpretation of prior studies, we present results that support our predictions. In the temperate zone, communities were more similar across spatial scales from centimeters to tens of kilometers and temporal scales up to one year than at lower latitudes. Since the patterns at northern latitudes were congruent with a null model, stochastic assembly processes are implicated. In contrast, the communities in the tropics were a dynamic spatial and temporal mosaic, with low similarity even across small spatial scales and high temporal turnover at both local and regional scales. Unlike the temperate zone, deterministic community assembly processes such as predation likely contributed to the high beta diversity in the tropics. Our results suggest that community assembly processes and temporal dynamics vary across latitude and help structure and maintain latitudinal patterns of diversity.


Asunto(s)
Organismos Acuáticos , Ecosistema , Invertebrados , Clima Tropical , Animales , Belice , Estados Unidos
18.
Ecology ; 96(10): 2758-70, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26649396

RESUMEN

Many theories regarding the evolution of inducible resistance in plants have an implicit spatial component, but most relevant population dynamic studies ignore spatial dynamics. We examined a spatially explicit model of plant inducible resistance and herbivore population dynamics to explore how realistic features of resistance and herbivore responses influence spatial patterning. Both transient and persistent spatial patterns developed in all models examined, where patterns manifested as wave-like aggregations of herbivores and variation in induction levels. Patterns arose when herbivores moved away from highly induced plants, there was a lag between damage and deployment of induced resistance, and the relationship between herbivore density and strength of the induction response had a sigmoid shape. These mechanisms influenced pattern formation regardless of the assumed functional relationship between resistance and herbivore recruitment and mortality. However, in models where induction affected herbivore mortality, large-scale herbivore population cycles driven by the mortality response often co-occurred with smaller scale spatial patterns driven by herbivore movement. When the mortality effect dominated, however, spatial pattern formation was completely replaced by spatially synchronized herbivore population cycles. Our results present a new type of ecological pattern formation driven by induced trait variation, consumer behavior, and time delays that has broad implications for the community and evolutionary ecology of plant defenses.


Asunto(s)
Herbivoria , Modelos Biológicos , Fenómenos Fisiológicos de las Plantas , Plantas/clasificación , Animales
19.
Ecology ; 95(5): 1370-83, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-25000768

RESUMEN

Effects of neighboring plants on herbivore damage to a focal plant (associational effects) have been documented in many systems and can lead to either increased or decreased herbivore attack. Mechanistic models that explain the observed variety of herbivore responses to local plant community composition have, however, been lacking. We present a model of herbivore responses to patches that consist of two plant types, where herbivore densities on a focal plant are determined by a combination of patch-finding, within-patch redistribution, and patch-leaving. Our analyses show that the effect of plant neighborhood on herbivores depends both on how plant and herbivore traits combine to affect herbivore movement and on how experimental designs reveal the effects of plant density and plant relative frequency. Associational susceptibility should be the dominant pattern when herbivores have biased landing rates within patches. Other behavioral decision rules lead to mixed responses, but a common pattern is that in mixed patches, one plant type experiences associational resistance while the other plant experiences associational susceptibility. In some cases, the associational effect may shift sign along a gradient of plant frequency, suggesting that future empirical studies should include more than two plant frequencies to detect nonlinearities. Finally, we find that associational susceptibility should be commonly observed in experiments using replacement designs, whereas associational resistance will be the dominant pattern when using additive designs. Consequently, outcomes from one experimental design cannot be directly compared to studies with other designs. Our model can also be translated to other systems with foragers searching for multiple resource types.


Asunto(s)
Herbivoria/fisiología , Plantas/clasificación , Animales , Modelos Biológicos , Dinámica Poblacional
20.
Transl Androl Urol ; 13(5): 833-845, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38855589

RESUMEN

Penile prosthesis implantation is an effective treatment for erectile dysfunction (ED) with high patient satisfaction and effectiveness. Unfortunately, infections remain a dreaded complication, often necessitating device removal and imposing a substantial healthcare cost. Biofilms are communities of microorganisms encased in a self-produced polymeric matrix that can attach to penile prostheses. Biofilms have been demonstrated on the majority of explanted prostheses for both infectious and non-infectious revisions and are prevalent even in asymptomatic patients. Biofilms play a role in microbial persistence and exhibit unique antibiotic resistance strategies that can lead to increased infection rates in revision surgery. Biofilms demonstrate physical barriers through the development of an extracellular polymeric substance (EPS) that hinders antibiotic penetrance and the bacteria within biofilms demonstrate reduced metabolic activity that weakens the efficacy of traditional antibiotics. Despite these challenges, new methods are being developed and investigated to prevent and treat biofilms. These treatments include surface modifications, biosurfactants, tissue plasminogen activator (tPA), and nitric oxide (NO) to prevent bacterial adhesion and biofilm formation. Additionally, novel antibiotic treatments are currently under investigation and include antimicrobial peptides (AMPs), bacteriophages, and refillable antibiotic coatings. This article reviews biofilm formation, the challenges that biofilms present to conventional antibiotics, current treatments, and experimental approaches for biofilm prevention and treatment.

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