Land-use change interacts with island biogeography to alter bird community assembly.

Anthropogenic activities have reshaped biodiversity on islands worldwide. However, it remains unclear how island attributes and land-use change interactively shape multiple facets of island biodiversity through community assembly processes. To answer this, we conducted bird surveys in various land-use types (mainly forest and farmland) using transects on 34 oceanic land-bridge islands in the largest archipelago of China. We found that bird species richness increased with island area and decreased with isolation, regardless of the intensity of land-use change. However, forest-dominated habitats exhibited lower richness than farmland-dominated habitats. Island bird assemblages generally comprised species that share more similar traits or evolutionary histories (i.e. functional and/or phylogenetic clustering) than expected if assemblages were randomly assembled. Contrary to our expectations, we observed that bird assemblages in forest-dominated habitats were more clustered on large and close islands, whereas assemblages in farmland-dominated habitats were more clustered on small islands. These contrasting results indicate that land-use change interacts with island biogeography to alter the community assembly of birds on inhabited islands. Our findings emphasize the importance of incorporating human-modified habitats when examining the community assembly of island biota, and further suggest that agricultural landscapes on large islands may play essential roles in protecting countryside island biodiversity.

A global analysis of avian island diversity-area relationships in the Anthropocene.

Research on island species-area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity-area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have 're-calibrated' the IDARs such that they resemble the historic period prior to recent extinctions.

Long-term changes in macroinvertebrate communities across high-latitude streams.

Long-term records of benthic macroinvertebrates in high-latitude streams are essential for understanding climatic changes, including extreme events (e.g. floods). Data extending over multiple decades are typically scarce. Here, we investigated macroinvertebrate community structural change (including alpha and beta diversity and gain and loss of species) over 22 years (1994-2016) in 10 stream systems across Denali National Park (Alaska, USA) in relation to climatological and meteorological drivers (e.g. air temperature, snowpack depth, precipitation). We hypothesised that increases in air temperature and reduced snowpack depth, due to climatic change, would reduce beta and gamma diversity but increase alpha diversity. Findings showed temporal trends in alpha diversity were variable across streams, with oscillating patterns in many snowmelt- and rainfall runoff-fed streams linked to climatic variation (temperature and precipitation), but increased over time in several streams supported by a mixture of water sources, including more stable groundwater-fed streams. Beta-diversity over the time series was highly variable, yet marked transitions were observed in response to extreme snowpack accumulation (1999-2000), where species loss drove turnover. Gamma diversity did not significantly increase or decrease over time. Investigating trends in individual taxa, several taxa were lost and gained during a relative constrained time period (2000-2006), likely in response to climatic variability and significant shifts in instream environmental conditions. Findings demonstrate the importance of long-term biological studies in stream ecosystems and highlight the vulnerability of high-latitude streams to climate change.

Extra terrestrials: drought creates niche space for rare invertebrates in a large-scale and long-term field experiment.

Freshwater habitats are drying more frequently and for longer under the combined pressures of climate change and overabstraction. Unsurprisingly, many aquatic species decline or become locally extinct as their benthic habitat is lost during stream droughts, but less is known about the potential 'winners': those terrestrial species that may exploit emerging niches in drying riverbeds. In particular, we do not know how these transient ecotones will respond as droughts become more extreme in the future. To find out we used a large-scale, long-term mesocosm experiment spanning a wide gradient of drought intensity, from permanent flows to full streambed dewatering, and analysed terrestrial invertebrate community assembly after 1 year. Droughts that caused stream fragmentation gave rise to the most diverse terrestrial invertebrate assemblages, including 10 species with UK conservation designations, and high species turnover between experimental channels. Droughts that caused streambed dewatering produced lower terrestrial invertebrate richness, suggesting that the persistence of instream pools may benefit these taxa as well as aquatic biota. Particularly intense droughts may therefore yield relatively few 'winners' among either aquatic or terrestrial species, indicating that the threat to riverine biodiversity from future drought intensification could be more pervasive than widely acknowledged.

A season for all things: Phenological imprints in Wikipedia usage and their relevance to conservation.

Phenology plays an important role in many human-nature interactions, but these seasonal patterns are often overlooked in conservation. Here, we provide the first broad exploration of seasonal patterns of interest in nature across many species and cultures. Using data from Wikipedia, a large online encyclopedia, we analyzed 2.33 billion pageviews to articles for 31,751 species across 245 languages. We show that seasonality plays an important role in how and when people interact with plants and animals online. In total, over 25% of species in our data set exhibited a seasonal pattern in at least one of their language-edition pages, and seasonality is significantly more prevalent in pages for plants and animals than it is in a random selection of Wikipedia articles. Pageview seasonality varies across taxonomic clades in ways that reflect observable patterns in phenology, with groups such as insects and flowering plants having higher seasonality than mammals. Differences between Wikipedia language editions are significant; pages in languages spoken at higher latitudes exhibit greater seasonality overall, and species seldom show the same pattern across multiple language editions. These results have relevance to conservation policy formulation and to improving our understanding of what drives human interest in biodiversity.

A global model of island species-area relationships.

The increase in species richness with island area (ISAR) is a well-established global pattern, commonly described by the power model, the parameters of which are hypothesized to vary with system isolation and to be indicative of ecological process regimes. We tested a structural equation model of ISAR parameter variation as a function of taxon, isolation, and archipelago configuration, using a globally distributed dataset of 151 ISARs encompassing a range of taxa and archipelago types. The resulting models revealed a negative relationship between ISAR intercept and slope as a function of archipelago species richness, in turn shaped by taxon differences and by the amount and disposition of archipelago area. These results suggest that local-scale (intra-archipelago) processes have a substantial role in determining ISAR form, obscuring the diversity patterns predicted by island theory as a function of archipelago isolation. These findings have implications for the use and interpretation of ISARs as a tool within biogeography, ecology, and conservation.

Cytogenetic analysis of 130 renal oncocytomas identify three distinct and mutually exclusive diagnostic classes of chromosome aberrations.

The cytogenetic alterations in renal oncocytoma (RO) are poorly understood. We analyzed 130 consecutive RO for karyotypic alterations. Clonal chromosome abnormalities were identified in 63 (49%) cases, which could be categorized into three classes of mutually exclusive cytogenetic categories. Class 1 (N = 20) RO had diploid karyotypes with characteristic 11q13 rearrangement in balanced translocations with 10 or more different chromosome partners in all cases. We identified recurrent translocation partners at 5q35, 6p21, 9p24, 11p13-14, and 11q23, and confirmed that CCND1 gene rearrangement at 11q13 utilizing fluorescence in situ hybridization (FISH). Class 2 RO (N = 25) exhibited hypodiploid karyotypes with loss of chromosome 1 and/or losses of Y in males and X in females in all cases. The class 3 tumors comprising of 18 cases showed diverse types of abnormalities with the involvement of two or more chromosomes exclusive of abnormalities seen in classes 1 and 2 tumors. Furthermore, karyotypically uninformative cases were subjected to FISH analysis to identify classes 1 and 2 abnormalities. In this group, we found similar frequencies of CCND1 rearrangement, loss of chromosome 1 or Y as with karyotypically abnormal cases. We validated our results against 91 tumors from the Mitelman database. Correlation of clinical data with all the three classes of ROs showed no clear evidence of overall patient survival. Our findings support the hypothesis that RO exhibit three principal cytogenetic categories, which may have different roles in initiation and/or progression. These cytogenetic markers provide a key tool in the diagnostic evaluation of RO.

Extreme drought pushes stream invertebrate communities over functional thresholds.

Functional traits are increasingly being used to predict extinction risks and range shifts under long-term climate change scenarios, but have rarely been used to study vulnerability to extreme climatic events, such as supraseasonal droughts. In streams, drought intensification can cross thresholds of habitat loss, where marginal changes in environmental conditions trigger disproportionate biotic responses. However, these thresholds have been studied only from a structural perspective, and the existence of functional nonlinearity remains unknown. We explored trends in invertebrate community functional traits along a gradient of drought intensity, simulated over 18 months, using mesocosms analogous to lowland headwater streams. We modelled the responses of 16 traits based on a priori predictions of trait filtering by drought, and also examined the responses of trait profile groups (TPGs) identified via hierarchical cluster analysis. As responses to drought intensification were both linear and nonlinear, generalized additive models (GAMs) were chosen to model response curves, with the slopes of fitted splines used to detect functional thresholds during drought. Drought triggered significant responses in 12 (75%) of the a priori-selected traits. Behavioural traits describing movement (dispersal, locomotion) and diet were sensitive to moderate-intensity drought, as channels fragmented into isolated pools. By comparison, morphological and physiological traits showed little response until surface water was lost, at which point we observed sudden shifts in body size, respiration mode and thermal tolerance. Responses varied widely among TPGs, ranging from population collapses of non-aerial dispersers as channels fragmented to irruptions of small, eurythermic dietary generalists upon extreme dewatering. Our study demonstrates for the first time that relatively small changes in drought intensity can trigger disproportionately large functional shifts in stream communities, suggesting that traits-based approaches could be particularly useful for diagnosing catastrophic ecological responses to global change.

Joint reconstruction of the initial pressure and speed of sound distributions from combined photoacoustic and ultrasound tomography measurements.

The initial pressure and speed of sound (SOS) distributions cannot both be stably recovered from photoacoustic computed tomography (PACT) measurements alone. Adjunct ultrasound computed tomography (USCT) measurements can be employed to estimate the SOS distribution. Under the conventional image reconstruction approach for combined PACT/USCT systems, the SOS is estimated from the USCT measurements alone and the initial pressure is estimated from the PACT measurements by use of the previously estimated SOS. This approach ignores the acoustic information in the PACT measurements and may require many USCT measurements to accurately reconstruct the SOS. In this work, a joint reconstruction method where the SOS and initial pressure distributions are simultaneously estimated from combined PACT/USCT measurements is proposed. This approach allows accurate estimation of both the initial pressure distribution and the SOS distribution while requiring few USCT measurements.

Analysis of emergency vascular surgery consults within a tertiary health care system.

OBJECTIVE: Patients with vascular disease often have multisystem atherosclerosis and multiple comorbidities requiring comprehensive interdisciplinary specialty care. Consultation is a critical component of a tertiary vascular surgery practice, but analysis of this service is under-reported in the literature. After-hours inpatient consultations and interhospital transfers are associated with urgent patient care. METHODS: A retrospective analysis of vascular surgery consultations was carried out from January 1, 2013, to December 31, 2013. Consultations included inpatient services, the emergency department, surgical and medical intensive care unit, and interhospital transfers. Data analysis included number of consults, time of consultation (during hours, 0700-1859; after hours, 1900-0659), referring service, nature, and outcome of consultation. Consultations were then classified as urgent if vascular surgical intervention was required as an intraoperative consultation, within 24 hours, or during the same hospitalization. Patients without a same-hospital vascular surgical intervention were classified as nonurgent. RESULTS: During a 1-year period, 823 independent consult requests of 749 patients were analyzed. It was found that 57.8% of after-hours consults resulted in urgent patient care (P = .003); 29.7% of medicine, 33.3% of medical intensive care unit, 41.9% of trauma surgery, and 60% of emergency department after-hours consultations were urgent; 73% of surgery and 79.2% of interhospital after-hours consults required urgent vascular surgical intervention. Extremity ischemia, aortic disease, and iatrogenic consults accounted for 44.8%, 20.4%, and 11.1% of after-hours consults, with 57.9%, 56.4%, and 70% requiring urgent vascular surgical intervention, respectively. CONCLUSIONS: After-hours consultations are not always associated with an urgent vascular surgical intervention. Nonurgent after-hours consultations are requested more frequently from some services and may present an opportunity for education that could improve workflow of the vascular workforce.

Closed loop control of lactate concentration in mammalian cell culture by Raman spectroscopy leads to improved cell density, viability, and biopharmaceutical protein production.

Accumulation of lactate in mammalian cell culture often negatively impacts culture performance, impeding production of therapeutic proteins. Many efforts have been made to limit the accumulation of lactate in cell culture. Here, we describe a closed loop control scheme based on online spectroscopic measurements of glucose and lactate concentrations. A Raman spectroscopy probe was used to monitor a fed-batch mammalian cell culture and predict glucose and lactate concentrations via multivariate calibration using partial least squares regression (PLS). The PLS models had a root mean squared error of prediction (RMSEP) of 0.27 g/L for glucose and 0.20 g/L for lactate. All glucose feeding was controlled by the Raman PLS model predictions. Glucose was automatically fed when lactate levels were beneath a setpoint (either 4.0 or 2.5 g/L) and glucose was below its own setpoint (0.5 g/L). This control scheme was successful in maintaining lactate levels at an arbitrary setpoint throughout the culture, as compared to the eventual accumulate of lactate to 8.0 g/L in the historical process. Automated control of lactate by restricted glucose feeding led to improvements in culture duration, viability, productivity, and robustness. Culture duration was extended from 11 to 13 days, and harvest titer increased 85% over the historical process. Biotechnol. Bioeng. 2016;113: 2416-2424. © 2016 Wiley Periodicals, Inc.

Outcomes after celiac artery coverage during thoracic endovascular aortic aneurysm repair.

OBJECTIVE: Coverage of celiac artery (CA) during thoracic endovascular aortic aneurysm repair (TEVAR) has been performed to extend the distal seal zone for which preliminary results and short-term follow-up have been reported. We aim to show the outcomes up to 81 months after CA coverage during TEVAR. METHODS: Patients undergoing TEVAR with coverage of the CA origin from 2005 to 2013 were retrospectively analyzed. Points of analysis include indications for covering the CA, demonstration of collateral circulation between the CA and superior mesenteric artery (SMA), anatomic features of the distal landing zone, rate of reintervention, technical success, presence of clinical ischemic symptoms after the procedure, and mortality. RESULTS: During the 9-year period, 366 patients underwent TEVAR, 18 (5%) of whom had CA coverage. Eleven (61%) had TEVAR with CA coverage due to a thoracic aneurysm, three (17%) had thoracic aortic dissection related to aneurysm, and four (22%) had previous TEVAR with a type Ib endoleak (EL) requiring distal coverage. Mesenteric angiography in preparation for TEVAR with CA coverage diagnosed a critical SMA stenosis in one patient that was treated with stenting before the index procedure. At the conclusion of the indicated procedure, two patients (11%) had a type Ia EL and two patients (11%) had a type Ib EL. Three of the type I ELs required reintervention. Two patients (11%) had a type II EL, both of which were managed with observation and resolved. Reintervention was required in 27% of patients. Postoperative complications included visceral ischemia in 2 (11%), weight loss in 1 (5%), spinal cord ischemia in 2 (11%), a cerebrovascular event in 1 (6%), and death in 1 (6%). The mean follow-up period was 38 months (range, 0.5-81 months). CONCLUSIONS: This analysis of outcomes up to 81 months supports the suitability of covering the CA in selected patients for extending the distal landing zone to the visceral aortic level above the SMA or when alternative branch vessel treatment is unavailable. Preoperative angiographic evaluation of the mesenteric collaterals and early postoperative surveillance may limit postoperative complications. Once the CA is covered, new symptoms do not develop unless the SMA is compromised.

The ecological impact of city lighting scenarios: exploring gap crossing thresholds for urban bats.

As the global population urbanizes, dramatic changes are expected in city lighting and the urban form, which may threaten the functioning of urban ecosystems and the services they deliver. However, little is known about the ecological impact of lighting in different urban contexts. Movement is an important ecological process that can be disrupted by artificial lighting. We explored the impact of lighting on gap crossing for Pipistrellus pipistrellus, a species of bat (Chiroptera) common within UK cities. We aimed to determine whether the probability of crossing gaps in tree cover varied with crossing distance and lighting level, through stratified field surveys. We then used the resulting data on barrier thresholds to model the landscape resistance due to lighting across an entire city and explored the potential impact of scenarios for future changes to street lighting. The level of illumination required to create a barrier effect reduced as crossing distance increased. For those gaps where crossing was recorded, bats selected the darker parts of gaps. Heavily built parts of the case study city were associated with large and brightly lit gaps, and spatial models indicate movement would be highly restricted in these areas. Under a scenario for brighter street lighting, the area of accessible land cover was further reduced in heavily built parts of the city. We believe that this is the first study to demonstrate how lighting may create resistance to species movement throughout an entire city. That connectivity in urban areas is being disrupted for a relatively common species raises questions about the impacts on less tolerant groups and the resilience of bat communities in urban centres. However, this mechanistic approach raises the possibility that some ecological function could be restored in these areas through the strategic dimming of lighting and narrowing of gaps.

Power-law scaling in intratumoral microbiota of colorectal cancer.

It has recently been proposed that the study of microbial dynamics in humans may gain insights from island biogeographical theory. Here, we test whether the diversity of the intratumoral microbiota of colorectal cancer tumors (CRC) follows a power law with tumor size akin to the island species-area relationship. We confirm a direct correlation between the quantity of Amplicon Sequence Variants (ASVs) within CRC tumors and tumor sizes, following a (log)power model, explaining 47% of the variation. Understanding the processes involved, potentially through the analogy of tumors and islands, may ultimately contribute to future clinical and therapeutic strategies.

A Semiautonomous Deep Learning System to Reduce False Positives in Screening Mammography.

Purpose To evaluate the ability of a semiautonomous artificial intelligence (AI) model to identify screening mammograms not suspicious for breast cancer and reduce the number of false-positive examinations. Materials and Methods The deep learning algorithm was trained using 123 248 two-dimensional digital mammograms (6161 cancers) and a retrospective study was performed on three nonoverlapping datasets of 14 831 screening mammography examinations (1026 cancers) from two U.S. institutions and one U.K. institution (2008-2017). The stand-alone performance of humans and AI was compared. Human plus AI performance was simulated to examine reductions in the cancer detection rate, number of examinations, false-positive callbacks, and benign biopsies. Metrics were adjusted to mimic the natural distribution of a screening population, and bootstrapped CIs and P values were calculated. Results Retrospective evaluation on all datasets showed minimal changes to the cancer detection rate with use of the AI device (noninferiority margin of 0.25 cancers per 1000 examinations: U.S. dataset 1, P = .02; U.S. dataset 2, P < .001; U.K. dataset, P < .001). On U.S. dataset 1 (11 592 mammograms; 101 cancers; 3810 female patients; mean age, 57.3 years ± 10.0 [SD]), the device reduced screening examinations requiring radiologist interpretation by 41.6% (95% CI: 40.6%, 42.4%; P < .001), diagnostic examinations callbacks by 31.1% (95% CI: 28.7%, 33.4%; P < .001), and benign needle biopsies by 7.4% (95% CI: 4.1%, 12.4%; P < .001). U.S. dataset 2 (1362 mammograms; 330 cancers; 1293 female patients; mean age, 55.4 years ± 10.5) was reduced by 19.5% (95% CI: 16.9%, 22.1%; P < .001), 11.9% (95% CI: 8.6%, 15.7%; P < .001), and 6.5% (95% CI: 0.0%, 19.0%; P = .08), respectively. The U.K. dataset (1877 mammograms; 595 cancers; 1491 female patients; mean age, 63.5 years ± 7.1) was reduced by 36.8% (95% CI: 34.4%, 39.7%; P < .001), 17.1% (95% CI: 5.9%, 30.1%: P < .001), and 5.9% (95% CI: 2.9%, 11.5%; P < .001), respectively. Conclusion This work demonstrates the potential of a semiautonomous breast cancer screening system to reduce false positives, unnecessary procedures, patient anxiety, and medical expenses. Keywords: Artificial Intelligence, Semiautonomous Deep Learning, Breast Cancer, Screening Mammography Supplemental material is available for this article. Published under a CC BY 4.0 license.

Risk scoring system to predict 3-year survival in patients treated for asymptomatic carotid stenosis.

OBJECTIVE: To identify risk factors and stratify their effect of compromising 3-year survival in patients treated for asymptomatic carotid disease based upon recently updated guidelines from the Society for Vascular Surgery. METHODS: Outcomes of 506 patients who underwent carotid intervention for asymptomatic carotid disease (1999-2008) were analyzed. Hospital computerized medical records were reviewed. When local records were sparse, Social Security Death Index was queried to confirm mortality. Following multivariable Cox regression analysis, a score was assigned based on the calculated hazard ratio (HR) in the following fashion: HR 1.5-1.9 = 1 point; HR 2.0-3.0 = 2 points; and HR >3 = 3 points. The sum of those points comprised the final score for each patient. Kaplan-Meier analyses were then performed to delineate survival differences. RESULTS: Seventy patients (13.83%) did not survive beyond 3 years after the procedure. Age >80 years (HR, 1.79; P = .05; score 1), diabetes mellitus (HR, 1.99; P < .05; score 1), coronary artery intervention (HR, 2.03; P < .01; score 2), severe chronic kidney disease defined as glomerular filtration rate <30 and not on dialysis (HR, 2.46; P = .03; score 2), dialysis patients (HR, 5.67; P = .001; score 3), and chronic obstructive pulmonary disease (HR, 3.53; P < .001; score 3) negatively influenced 3-year survival. Patients with score ≤2 experienced 3-year mortality of 6.0%, whereas score >2 was associated with 31.6% 3-year mortality (HR, 6.10; P < .001). The score value was not associated with the stroke rate at any time point. The resultant score was validated in a separate population of patients with symptomatic carotid disease. CONCLUSIONS: This easy predictive score underscores the association of medical risk factors with decreased 3-year survival. This finding may impact future clinical decisions for management of asymptomatic carotid disease.

Comparison of outcomes following endovascular repair of abdominal aortic aneurysms based on size threshold.

INTRODUCTION: Size threshold for operative repair of abdominal aortic aneurysms (AAAs) has been determined based on risks and outcomes of open repair vs surveillance. The influence of endovascular aneurysm repair (EVAR) on this threshold is less established. The purpose of this study is to determine whether long-term outcomes following EVAR are affected by maximum diameter at the time of treatment. METHODS: Patients undergoing EVAR with modular stent grafts from 2000 to 2011 were identified from a prospectively maintained database and stratified by maximum aortic diameter at the time of repair: small (4.0-4.9 cm), medium (5.0-5.9 cm), and large (≥6.0 cm). Comparisons of demographics, indications for repair, perioperative complications, and long-term outcomes were made using analysis of variance, χ(2), and Kaplan-Meier plots. RESULTS: Seven hundred forty patients were identified: 157 (21.2%) small, 374 (50.5%) medium, and 209 (28.2%) large. Patients differed by mean age (69.3 ± 8.09, 71.7 ± 8.55, and 73.6 ± 8.77 years for small, medium, and large, respectively; P < .001), coronary artery disease (42% small, 57% medium, 51.2% large; P = .01), prior coronary angioplasty (14.6% small, 18.2% medium, 9.6% large; P = .02), congestive heart failure (5.7% small, 15.2% medium, 19.6% large; P = .01), prior vascular surgery (7% small, 15.8% medium, 10% large; P = .016), and chronic obstructive pulmonary disease (21% small, 27% medium, 33% large; P = .038). Small AAAs were more frequently symptomatic (19.7% small, 7.5% medium, 8.1% large; P < .001). There was no difference in perioperative complication rates (P = .399), expansion ≥5 mm (2.6% small, 5.6% medium, 7.2% large; P = .148), or all-type endoleak (40.8% small, 41.7% medium, 44.5% large; P = .73). Small AAAs developed fewer type I endoleaks (5.1% vs 6.95% medium and 14.8% large; P = .001). Compared with small AAAs, both medium (P = .39) and large (P < .001) required secondary intervention more frequently, with hazard ratios of 2.32 (95% confidence interval, 1.045-5.156) and 4.74 (95% confidence interval, 2.115-10.637), respectively. Ten-year survival was 72%, 63.1%, and 49.8% in the small, medium, and large groups, respectively (P < .001) with one rupture-related death after EVAR in the large group. All-cause mortality differed among the 75- to 84-year-old patients (30.4% small, 51.6% medium, 55.7% large; P = .017). CONCLUSIONS: EVAR for small AAAs shows improved long-term outcomes than for age-matched patients with larger aneurysms.

Upper extremity thromboembolism in a patient with subclavian steal syndrome.

Subclavian steal is the physiologic process whereby blood flow through a vertebral artery is reversed at the level of the basilar artery as a means of supplying arterial inflow to the ipsilateral subclavian artery. This occurs in the setting of ipsilateral subclavian artery origin occlusion. We describe a case in which a patient with subclavian steal syndrome developed acute upper extremity ischemia secondary to thromboemboli from a chronically occluded ipsilateral subclavian stent (at the origin of the left subclavian artery). He subsequently underwent staged left upper extremity arterial thromboembolectomy followed by definitive revascularization via carotid-subclavian bypass. In addition, subclavian artery ligation proximal to the ipsilateral vertebral artery was performed. The patient's sensory and motor neurologic hand function returned to baseline with restoration of symmetric upper extremity arterial occlusion pressures and pulse volume recordings. A search of the literature revealed that this was the first case report of acute thromboembolic hand ischemia in the setting of subclavian steal.

Fourier domain multispectral multiple scattering low coherence interferometry.

We have implemented multispectral multiple scattering low coherence interferometry (ms2/LCI) with Fourier domain data collection. The ms2/LCI system is designed to localize features with spectroscopic contrast with millimeter resolution up to 1 cm deep in scattering samples by using photons that have undergone multiple low-angle (forward) scattering events. Fourier domain detection both increases the data acquisition speed of the system and gives access to rich spectroscopic information, compared to the previous single channel, time-domain implementation. Separate delivery and detection angular apertures reduce collection of the diffuse background signal in order to isolate localized spectral features from deeper in scattering samples than would be possible with traditional spectroscopic optical coherence tomography. Light from a supercontinuum source is used to acquire absorption spectra of chromophores in the visible range within a tissue-like scattering phantom. An intensity modulation and digital lock-in detection scheme is implemented to mitigate relative intensity and spectral noise inherent in supercontinuum sources. The technical parameters of the system and comparative analysis are presented.