Comparative visual function in five sciaenid fishes inhabiting Chesapeake Bay

Maintaining optimal visual performance is a difficult task in the photodynamic coastal and estuarine waters in which western North Atlantic sciaenid fishes support substantial commercial and recreational fisheries. Unavoidable tradeoffs exist between visual sensitivity and resolution, yet sciaenid visual systems have not been characterized despite strong species-specific ecomorphological and microhabitat differentiation. We therefore used electroretinographic techniques to describe the light sensitivities, temporal properties, and spectral characteristics of the visual systems of five sciaenids common to Chesapeake Bay, USA: weakfish (Cynoscion regalis), spotted seatrout (Cynoscion nebulosus), red drum (Sciaenops ocellatus), Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus). Benthic sciaenids exhibited higher sensitivities and broader dynamic ranges in white light V/logI experiments than more pelagic forms. Sensitivities of the former were at the lower (more sensitive) end of an emerging continuum for coastal fishes. Flicker fusion frequency experiments revealed significant interspecific differences at maximum intensities that correlated with lifestyle and habitat, but no specific differences at dimmer intensities. Spectral responses of most sciaenids spanned 400-610 nm, with significant diel differences in weakfish and Atlantic croaker. Weakfish, a crepuscular predator, also responded to ultraviolet wavelengths; this characteristic may be more useful under less turbid conditions. Collectively, these results suggest that sciaenids are well adapted to the dynamic photoclimate of the coastal and estuarine waters they inhabit. However, the recent anthropogenic degradation of water quality in coastal environments, at a pace faster than the evolution of visual systems, has amplified the importance of characterizing visual function in managed aquatic fauna

Comparative visual function in four piscivorous fishes inhabiting Chesapeake Bay

Maintaining optimal visual performance is a difficult task in photodynamic coastal and estuarine waters because of the unavoidable tradeoffs between luminous sensitivity and spatial and temporal resolution, yet the visual systems of coastal piscivores remain understudied despite differences in their ecomorphology and microhabitat use. We therefore used electroretinographic techniques to describe the light sensitivities, temporal properties and spectral sensitivities of the visual systems of four piscivorous fishes common to coastal and estuarine waters of the western North Atlantic: striped bass (Morone saxatilis), bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus) and cobia (Rachycentron canadum). Benthic summer flounder exhibited higher luminous sensitivity and broader dynamic range than the three pelagic foragers. The former were at the more sensitive end of an emerging continuum for coastal fishes. By contrast, pelagic species were comparatively less sensitive, but showed larger day-night differences, consistent with their use of diel light-variant photic habitats. Flicker fusion frequency experiments revealed significant interspecific differences at maximum intensities that correlated with lifestyle and habitat. Spectral responses of most species spanned 400-610nm, with significant day-night differences in striped bass and bluefish. Anadromous striped bass additionally responded to longer wavelengths, similar to many freshwater fishes. Collectively, these results suggest that pelagic piscivores are well adapted to bright photoclimates, which may be at odds with the modern state of eutrified coastal and estuarine waters that they utilize. Recent anthropogenic degradation of water quality in coastal environments, at a pace faster than the evolution of visual systems, may impede visually foraging piscivores, change selected prey, and eventually restructure ecosystems

Acoustic pressure and particle motion thresholds in six sciaenid fishes

Sciaenid fishes are important models of fish sound production, but investigations into their auditory abilities are limited to acoustic pressure measurements on five species. In this study, we used auditory brainstem response ( ABR) to assess the pressure and particle acceleration thresholds of six sciaenid fishes commonly found in Chesapeake Bay, eastern USA: weakfish ( Cynoscion regalis), spotted seatrout ( Cynoscion nebulosus), Atlantic croaker ( Micropogonias undulatus), red drum ( Sciaenops ocellatus), spot ( Leiostomus xanthurus) and northern kingfish ( Menticirrhus saxatilis). Experimental subjects were presented with pure 10 ms tone bursts in 100 Hz steps from 100 Hz to 1.2 kHz using an airborne speaker. Sound stimuli, monitored with a hydrophone and geophone, contained both pressure and particle motion components. Sound pressure and particle acceleration thresholds varied significantly among species and between frequencies; audiograms were notably flatter for acceleration than pressure at low frequencies. Thresholds of species with diverticulae projecting anteriorly from their swim bladders ( weakfish, spotted seatrout, and Atlantic croaker) were typically but not significantly lower than those of species lacking such projections ( red drum, spot, northern kingfish). Sciaenids were most sensitive at low frequencies that overlap the peak frequencies of their vocalizations. Auditory thresholds of these species were used to estimate idealized propagation distances of sciaenid vocalizations in coastal and estuarine environments

Upper respiratory symptoms worsen over time and relate to clinical phenotype in COPD.

Copyright © 2015 by the American Thoracic Society.Rationale: How nasal symptoms in patients with chronic obstructive pulmonary disease (COPD) change over time and resolve during naturally occurring exacerbations has not been described previously. Objectives: To evaluate the evolution and impact of upper airway symptoms in a well-defined COPD cohort when stable and at exacerbation. Methods: Patients in the LondonCOPDcohortwere asked about the presence of nasal symptoms (nasal discharge, sneezing, postnasal drip, blocked nose, and anosmia) over an 8-year period (2005-2013) every 3 months at routine clinic visits while in a stable state and daily during exacerbations with the use of diary cards. Data were prospectively collected, and, in a subgroup of patients,COPDAssessment Test scores and human rhinovirus identification by polymerase chain reaction were available. Patients were also defined as having infrequent or frequent exacerbations (<2 or ≥2 exacerbations/yr, respectively). Measurements and Main Results: At an aggregate of 4,368 visits, 209 patients with COPD were asked about their nasal symptoms. At 2,033 visits when the patients were stable, the odds ratio (OR) for nasal discharge increased by 1.32% per year (95% confidence interval [CI], 1.19-1.45; P<0.001); the OR for sneezing increased by 1.16%(95%CI, 1.05-1.29;P = 0.005); theORfor postnasal drip increased by 1.18% (95% CI, 1.03-1.36; P=0.016); and theOR for anosmia increased by 1.19% (95% CI, 1.03-1.37; P = 0.015). At visits when the patients were having exacerbations, nasal discharge was present for 7 days and blocked nose, sneezing, and postnasal drip increased for just 3 days. Anosmia did not change. Nasal dischargewasmore likely inpatientswith frequent exacerbations (OR, 1.96; 95% CI, 1.17-3.28; P= 0.011), and COPD Assessment Test scores were higher by 1.06 units (95% CI, 0.32-1.80; P=0.005) when patients were stable and higher by 1.30 units (95% CI, 0.05-2.57; P= 0.042) during exacerbations. Conclusions: Upper airway symptoms increase over time in patients with COPD and are related to the frequent exacerbation phenotype. These longitudinal changes may be due to increasing airway inflammation or to progression of COPD

Inflammatory thresholds and the species-specific effects of colonising bacteria in stable chronic obstructive pulmonary disease

There has been increasing interest in the use of newer, culture-independent techniques to study the airway microbiome of COPD patients. We investigated the relationships between the three common potentially pathogenic microorganisms (PPMs) Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, as detected by quantitative PCR (qPCR), and inflammation and health status in stable patients in the London COPD cohort

Community-based recruitment of patients with COPD into clinical research.

Identifying subjects for clinical trials is difficult and the evidence base for recruitment strategies is limited, particularly in the field of COPD. We compared the efficiency and patient characteristics of different community-based recruitment strategies during a non-commercial COPD trial in the UK. Recruiting from general practice COPD registers was less efficient and identified patients with significantly milder disease than recruiting through pulmonary rehabilitation and patient groups. We report our experience and propose that pulmonary rehabilitation and patient groups may represent an enriched pool of COPD patients to recruit into clinical trials

Effects of different antibiotic classes on airway bacteria in stable COPD using culture and molecular techniques: a randomised controlled trial

Long-term antibiotic therapy is used to prevent exacerbations of COPD but there is uncertainty over whether this reduces airway bacteria. The optimum antibiotic choice remains unknown. We conducted an exploratory trial in stable patients with COPD comparing three antibiotic regimens against placebo