TDFCAM: A method for estimating stable isotope trophic discrimination in wild populations.

Stable isotope mixing models (SIMMs) are widely used for characterizing wild animal diets. Such models rely upon using accurate trophic discrimination factors (TDFs) to account for the digestion, incorporation, and assimilation of food. Existing methods to calculate TDFs rely on controlled feeding trials that are time-consuming, often impractical for the study taxon, and may not reflect natural variability of TDFs present in wild populations.We present TDFCAM as an alternative approach to estimating TDFs in wild populations, by using high-precision diet estimates from a secondary methodological source-in this case nest cameras-in lieu of controlled feeding trials, and provide a framework for how and when it should be applied.In this study, we evaluate the TDFCAM approach in three datasets gathered on wild raptor nestlings (gyrfalcons Falco rusticolus; peregrine falcons Falco perigrinus; common buzzards Buteo buteo) comprising contemporaneous δ13C & δ15N stable isotope data and high-quality nest camera dietary data. We formulate Bayesian SIMMs (BSIMMs) incorporating TDFs from TDFCAM and analyze their agreement with nest camera data, comparing model performance with those based on other relevant TDFs. Additionally, we perform sensitivity analyses to characterize TDFCAM variability, and identify ecological and physiological factors contributing to that variability in wild populations.Across species and tissue types, BSIMMs incorporating a TDFCAM outperformed any other TDF tested, producing reliable population-level estimates of diet composition. We demonstrate that applying this approach even with a relatively low sample size (n < 10 individuals) produced more accurate estimates of trophic discrimination than a controlled feeding study conducted on the same species. Between-individual variability in TDFCAM estimates for ∆13C & ∆15 N increased with analytical imprecision in the source dietary data (nest cameras) but was also explained by natural variables in the study population (e.g., nestling nutritional/growth status and dietary composition).TDFCAM is an effective method of estimating trophic discrimination in wild animal populations. Here, we use nest cameras as source dietary data, but this approach is applicable to any high-accuracy method of measuring diet, so long as diet can be monitored over an interval contemporaneous with a tissue's isotopic turnover rate.

Isotopic niche partitioning and individual specialization in an Arctic raptor guild.

Intra- and inter-specific resource partitioning within predator communities is a fundamental component of trophic ecology, and one proposed mechanism for how populations partition resources is through individual niche variation. The Niche Variation Hypothesis (NVH) predicts that inter-individual trait variation leads to functional trade-offs in foraging efficiency, resulting in populations composed of individual dietary specialists. The degree to which niche specialization persists within a population is plastic and responsive to fluctuating resource availability. We quantified niche overlap and tested the NVH within an Arctic raptor guild, focusing on three species that employ different foraging strategies: golden eagles (generalists); gyrfalcons (facultative specialists); and rough-legged hawks (specialists). Tundra ecosystems exhibit cyclic populations of arvicoline rodents (lemmings and voles), providing a unique system in which to examine predator diet in response to interannual fluctuations in resource availability. Using blood δ13C and δ15N values from 189 raptor nestlings on Alaska's Seward Peninsula (2014-2019), we calculated isotopic niche width and used Bayesian stable isotope mixing models (BSIMMs) to characterize individual specialization and test the NVH. Nest-level specialization estimated from stable isotopes was strongly correlated with indices of specialization based on camera trap data. We observed a high degree of isotopic niche overlap between the three species and gyrfalcons displayed a positive relationship between individual specialization and population niche width on an interannual basis consistent with the NVH. Our findings suggest plasticity in niche specialization may reduce intra- and inter-specific resource competition under dynamic ecological conditions.

Haematophagous ectoparasites lower survival of and have detrimental physiological effects on golden eagle nestlings.

Haematophagous ectoparasites can directly affect the health of young animals by depleting blood volume and reducing energetic resources available for growth and development. Less is known about the effects of ectoparasitism on stress physiology (i.e. glucocorticoid hormones) or animal behaviour. Mexican chicken bugs (Haematosiphon inodorus; Hemiptera: Cimicidae) are blood-sucking ectoparasites that live in nesting material or nest substrate and feed on nestling birds. Over the past 50 years, the range of H. inodorus has expanded, suggesting that new hosts or populations may be vulnerable. We studied the physiological and behavioural effects of H. inodorus on golden eagle (Aquila chrysaetos) nestlings in southwestern Idaho. We estimated the level of H. inodorus infestation at each nest and measured nestling mass, haematocrit, corticosterone concentrations, telomere lengths and recorded early fledging and mortality events. At nests with the highest levels of infestation, nestlings had significantly lower mass and haematocrit. In addition, highly parasitized nestlings had corticosterone concentrations twice as high on average (42.9 ng/ml) than non-parasitized nestlings (20.2 ng/ml). Telomeres of highly parasitized female nestlings significantly shortened as eagles aged, but we found no effect of parasitism on the telomeres of male nestlings. Finally, in nests with higher infestation levels, eagle nestlings were 20 times more likely to die, often because they left the nest before they could fly. These results suggest that H. inodorus may limit local golden eagle populations by decreasing productivity. For eagles that survived infestation, chronically elevated glucocorticoids and shortened telomeres may adversely affect cognitive function or survival in this otherwise long-lived species. Emerging threats from ectoparasites should be an important management consideration for protected species, like golden eagles.

Bayesian stable isotope mixing models effectively characterize the diet of an Arctic raptor.

Bayesian stable isotope mixing models (BSIMMs) for δ13 C and δ15 N can be a useful tool to reconstruct diets, characterize trophic relationships, and assess spatiotemporal variation in food webs. However, use of this approach typically requires a priori knowledge on the level of enrichment occurring between the diet and tissue of the consumer being sampled (i.e. a trophic discrimination factor or TDF). Trophic discrimination factors derived from captive feeding studies are highly variable, and it is challenging to select the appropriate TDF for diet estimation in wild populations. We introduce a novel method for estimating TDFs in a wild population-a proportionally balanced equation that uses high-precision diet estimates from nest cameras installed on a subset of nests in lieu of a controlled feeding study (TDFCAM ). We tested the ability of BSIMMs to characterize diet in a free-living population of gyrfalcon Falco rusticolus nestlings by comparing model output to high-precision nest camera diet estimates. We analysed the performance of models formulated with a TDFCAM against other relevant TDFs and assessed model sensitivity to an informative prior. We applied the most parsimonious model inputs to a larger sample to analyse broad-scale temporal dietary trends. Bayesian stable isotope mixing models fitted with a TDFCAM and uninformative prior had the best agreement with nest camera data, outperforming TDFs derived from captive feeding studies. BSIMMs produced with a TDFCAM produced reliable diet estimates at the nest level and accurately identified significant temporal shifts in gyrfalcon diet within and between years. Our method of TDF estimation produced more accurate estimates of TDFs in a wild population than traditional approaches, consequently improving BSIMM diet estimates. We demonstrate how BSIMMs can complement a high-precision diet study by expanding its spatiotemporal scope of inference and recommend this integrative methodology as a powerful tool for future trophic studies.

SUNDROP: six years of screening for retinopathy of prematurity with telemedicine.

OBJECTIVE: To report the 6-year results of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) initiative in the context of telemedicine screening initiatives for retinopathy of prematurity (ROP). DESIGN: A retrospective analysis. PARTICIPANTS: Premature newborns requiring ROP screening at 6 neonatal intensive care units from December 1, 2005, to November 30, 2011. METHODS: Infants were evaluated via remote retinal photography by an ROP specialist. A total of 608 preterm infants meeting ROP examination criteria were screened with the RetCam II/III (Clarity Medical Systems, Pleasanton, Calif.). Primary outcomes were treatment-warranted ROP (TW-ROP) and adverse anatomical events. RESULTS: During the 6 years, 1216 total eyes were screened during 2169 examinations, generating 26 970 retinal images, an average of 3.56 examinations and 44.28 images per patient. Twenty-two (3.6%) of the infants screened met criteria for TW-ROP. Compared with bedside binocular ophthalmoscopy, remote interpretation of RetCam II/III images had a sensitivity of 100%, specificity of 99.8%, positive predicative value of 95.5%, and negative predicative value of 100% for the detection of TW-ROP. No adverse anatomical outcomes were observed for any enrolled patient. CONCLUSIONS: The 6-year results for the SUNDROP telemedicine initiative were highly favourable with respect to diagnostic accuracy. Telemedicine appears to be a safe, reliable, and cost-effective complement to the efforts of ROP specialists, capable of increasing patient access to screening and focusing the resources of the current ophthalmic community on infants with potentially vision-threatening disease.

Lack of efficacy with 1064-nm neodymium:yttrium-aluminum-garnet laser for the treatment of onychomycosis: a randomized, controlled trial.

BACKGROUND: Laser therapies have been Food and Drug Administration approved for temporary nail plate clearance; however, there is minimal evidence of their long-term efficacy. OBJECTIVE: We sought to evaluate the clinical and mycological clearance of toenails treated with 1064-nm neodymium:yttrium-aluminum-garnet laser versus no treatment. METHODS: This was a randomized, controlled, single-center trial comparing 2 treatments with 1064-nm neodymium:yttrium-aluminum-garnet laser (fluence of 5 J/cm(2), rate of 6 Hz) spaced 2 weeks apart versus no treatment in 27 patients (N = 125 affected nails) with clinical and mycological diagnosis of onychomycosis. At 3 months, patients were assessed with mycological cultures and proximal nail plate measurements. Patients treated with laser were also assessed with proximal nail plate measurements at 12 months. RESULTS: At 3 months, 33% of patients treated with laser achieved a negative mycological culture compared with 20% of the control group (P = .49), and had more proximal nail plate clearance compared with control subjects (0.44 vs 0.15 mm, P = .18), which was not statistically significant. At 12 months, there was no difference in nail plate clearance between laser versus control subjects (0.24 vs 0.15 mm, P = .59). LIMITATIONS: Our study was limited by the small sample size and number of treatments. CONCLUSIONS: There was no significant mycological culture or clinical nail plate clearance with 1064-nm neodymium:yttrium-aluminum-garnet laser compared with control.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): five years of screening with telemedicine.

BACKGROUND AND OBJECTIVE: To report the 5-year results of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative. PATIENTS AND METHODS: Infants requiring retinopathy of prematurity (ROP) screening at six neonatal intensive care units from December 1, 2005, to November 30, 2010, were evaluated with remote retinal photography by an ROP specialist. Every infant received outpatient binocular indirect ophthalmoscope examinations until termination criteria were achieved or until treatment. Outcomes were treatment-warranted ROP (TW-ROP, ETROP type 1) and adverse anatomical events. RESULTS: Five hundred eleven infants (1,022 eyes) were screened. Fifteen infants had TW-ROP and underwent laser photocoagulation. The TW-ROP cohort had significantly lower birth weight and gestational age (both P < .001). No patient progressed to adverse anatomical outcomes and no case of TW-ROP was missed. Tele-medicine had 100% sensitivity, 99.8% specificity, 93.8% positive predictive value, and 100% negative predictive value for detection of TW-ROP. CONCLUSION: Telemedicine demonstrates high diagnostic accuracy for detection of TW-ROP and can complement ROP screening.

Alcohol consumption and risk of melanoma and non-melanoma skin cancer in the Women's Health Initiative.

PURPOSE: The relationship between alcohol consumption and preference of alcohol type with hazard of melanoma (MM) and risk of non-melanoma skin cancer (NMSC) was examined in the Women's Health Initiative (WHI) Observational Study (OS). METHODS: A prospective cohort of 59,575 White postmenopausal women in the WHI OS (mean age 63.6) was analyzed. Cox proportional hazards models and logistic regression techniques were used to assess the hazard and risk of physician-adjudicated MM and self-reported NMSC, respectively, after adjusting for potential confounders including measures of sun exposure and skin type. RESULTS: Over 10.2 mean years of follow-up, 532 MM cases and 9,593 NMSC cases occurred. A significant relationship between amount of alcohol consumed and both MM and NMSC was observed, with those who consume 7+ drinks per week having a higher hazard of MM (HR 1.64 (1.09, 2.49), p global = 0.0013) and higher risk of NMSC (OR 1.23 (1.11, 1.36), p global < 0.0001) compared to non-drinkers. Lifetime alcohol consumption was also positively associated with hazard of MM (p = 0.0011) and risk of NMSC (p < 0.0001). Further, compared to non-drinkers, a preference for either white wine or liquor was associated with an increased hazard of MM (HR 1.52 (1.02, 2.27) for white wine; HR 1.65 (1.07, 2.55) for liquor) and risk of NMSC (OR 1.16 (1.05, 1.28) for white wine; OR 1.26 (1.13, 1.41) for liquor). CONCLUSIONS: Higher current alcohol consumption, higher lifetime alcohol consumption, and a preference for white wine or liquor were associated with increased hazard of MM and risk of NMSC.

A new paradigm for incorporating the joint statement screening guidelines for retinopathy of prematurity into clinical practice: outcomes from a quaternary referral program.

BACKGROUND AND OBJECTIVE: This study examines patient experience at a quaternary referral pediatric clinic with a retinopathy of prematurity (ROP) screening program that monitors infants at least on a weekly basis for any stage of ROP. PATIENTS AND METHODS: Admission records of 399 prematurely born patients treated at the Byers Eye Institute outpatient ROP clinic were retrospectively reviewed. Patients were categorized according to ROP status and whether they completed, canceled, or failed to show up for scheduled examinations. Demographic information was collected from medical records. RESULTS: Of 1,823 scheduled ROP-related visits, 327 (17.9%) resulted in cancellations and 90 (4.9%) in no-shows, with 238 missed visits due to caregiver-related and 149 due to caregiver-unrelated reasons. Of 399 total patients, 142 (35.6%) canceled or failed to show up for at least one appointment because of caregiver-related reasons. CONCLUSION: More than one-third of patients with ROP canceled or missed appointments. The true risk of delay is difficult to assess because all patients requiring treatment received it prior to discharge from the hospital. To achieve maximal compliance with joint statement guidelines on ROP screening, patients should be scheduled for examination earlier than recommended.

Lower skin cancer risk in women with higher body mass index: the women's health initiative observational study.

The unclear relationship of obesity to incident melanoma and nonmelanoma skin cancer (NMSC) risks was evaluated in the large, geographically diverse longitudinal, prospective Women's Health Initiative (WHI) observational study. Risks of melanoma and NMSC in normal weight women were compared with risks in overweight [body mass index (BMI) = 25-29.0 kg/m(2)] and obese (BMI ≥ 30 kg/m(2)) women, using Cox proportional hazards models for melanoma and logistic regression for NMSC. Over a mean 9.4 years of follow-up, there were 386 melanoma and 9,870 NSMC cases. Risk of melanoma did not differ across weight categories (P = 0.86), whereas in fully adjusted models, NMSC risk was lower in overweight [OR, 0.93; 95% confidence interval (CI), 0.89-0.99] and obese (OR, 0.85; 95% CI, 0.80-0.91) women (P < 0.001). Excess body weight was not associated with melanoma risk in postmenopausal women but was inversely associated with NMSC risk, possibly due to lower sun exposure in overweight and obese women. This supports previous work demonstrating the relationship between excess body weight and skin cancer risk.

Academic productivity and its relationship to physician salaries in the University of California Healthcare System.

OBJECTIVES: To evaluate whether physicians with higher academic productivity, as measured by the number of publications in Scopus and the Scopus Hirsch index (h-index), earn higher salaries. METHODS: This was a cross-sectional study. Participants were ophthalmologists, otolaryngologists, neurosurgeons, and neurologists classified as "top earners" (>$100,000 annually) within the University of California (UC) healthcare system in 2008. Bibliometric searches on Scopus were conducted to retrieve the total number of publications and Hirsch indices (h-index), a measure of academic productivity. The association between the number of publications and h-index on physicians' total compensation was determined with multivariate regression models after controlling for the four specialties (ophthalmology, otolaryngology, neurosurgery, and neurology), the five institutions (UC San Francisco, UC Los Angeles, UC San Diego, UC Irvine, and UC Davis), and academic rank (assistant professor, associate professor, and professor). RESULTS: The UC healthcare system departments reported 433 faculty physicians among the four specialties, with 71.6% (n = 310) earning more than $100,000 in 2008 and classifying as top earners. After controlling for the specialty, institution, and ranking, there was a significant association between the number of publications on salary (P < 0.000001). Scopus number of publications and h-index were correlated (P < 0.001). Scopus h-index was of borderline significance in predicting physician salary (P = 0.12). Physicians with higher Scopus publications had higher total salaries across all four specialties. Every 10 publications were associated with a 2.40% increase in total salary after controlling for specialty, institution, rank, and chair. CONCLUSIONS: Ophthalmologists, otolaryngologists, neurosurgeons, and neurologists in the UC healthcare system who are more academically productive receive greater remuneration.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): four-years of screening with telemedicine.

PURPOSE: To report the four-year experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative, which was developed to reduce the risk of blindness from retinopathy of prematurity (ROP). MATERIALS AND METHODS: A retrospective analysis of the SUNDROP archival data between 12/1/2005 and 11/30/2009. A total of 410 consecutively enrolled infants meeting ROP screening criteria had nurse-obtained fundoscopic images evaluated remotely by an ROP specialist. Every infant then received at least one dilated bedside binocular indirect ophthalmoscope (BIO) examination within one week of discharge. All infants were then followed with both telemedicine images and bedside evaluation in clinic according to recommended screening timelines. Primary outcomes were treatment-warranted ROP (TW-ROP), defined as Early Treatment of ROP Type 1, and adverse anatomical outcomes. RESULTS: The SUNDROP telemedicine screening initiative has not missed any TW-ROP in its four-year evaluation period. A total of 410 infants (820 eyes) were imaged, resulting in 1486 examinations and 18,097 unique images. An average of 12.2 images were obtained per patient. Fourteen infants met TW-ROP criteria on telemedicine examination. After bedside evaluation, 13 infants required laser photocoagulation and one was followed until he spontaneously regressed. Infants with TW-ROP had a significantly lower gestational age (24.9 weeks), birth weight (658.7 grams), and were more likely to be male than the no TW-ROP cohort (all p values <0.00001). Telemedicine had a calculated sensitivity of 100%, specificity of 99.8%, positive predicative value of 92.9% and negative predictive value of 100% for the detection of TW-ROP. No patient progressed to retinal detachment or any adverse anatomical outcome. CONCLUSIONS: The SUNDROP initiative demonstrated a high degree of diagnostic reliability and was able to capture all infants with TW-ROP. Telemedicine offers a cost-effective, reliable and accurate screening methodology for identifying infants with TW-ROP without sacrificing quality of care.

Reconsidering the diagnostic and prognostic utility of LN-2 for undifferentiated pleomorphic sarcoma and atypical fibroxanthoma.

The topic of distinguishing atypical fibroxanthoma (AFX) from undifferentiated pleomorphic sarcoma (UPS), formerly malignant fibrous histiocytoma, is highly controversial. Although their clinical behavior is disparate, AFX and UPS commonly appear nearly identical on routine histopathologic examination. Although conceptually useful, subcategorization of UPS into superficial (confined to the dermis and subcutaneous tissue) and deep (involvement of fascia and deeper structures) types has not improved our ability to differentiate UPS from AFX. Numerous authors have purported LN-2 (CD74) immunopositivity as able to distinguish UPS from AFX and to predict those rare AFX likely to behave aggressively, although only a single prior study has been dedicated to evaluating this marker. We performed LN-2 staining of 14 AFX, 8 superficial UPS, and 65 deep UPS specimens using an identical protocol as described by prior authors. Of the 73 total UPS specimens, only 1 (1.4%) stained strongly with LN-2, as compared with 3 of 14 (21%) AFX (P = 0.012). One of 2 (50%) clinically aggressive AFX tumors that later exhibited both local recurrence and metastasis stained strongly for LN-2, whereas 2 of 12 (17%) of the more indolent tumors stained strongly with this marker (P = 0.40). Our data do not replicate prior reports of LN-2 as a sensitive and specific marker for UPS, or as indicative of prognosis for AFX, and therefore does not support the use of LN-2 as either a diagnostic or prognostic marker.

The evolving conception and management challenges of malignant fibrous histiocytoma.

BACKGROUND: Malignant fibrous histiocytoma (MFH) is a rare and aggressive tumor. Mohs micrographic surgery (MMS) has been reported as an effective treatment, although most cases were published before advances in cytopathologic techniques led to reclassification of many tumors. OBJECTIVE: To evaluate a contemporary cohort of individuals with MFH and analyze management practices. METHODS: We reviewed all cases of MFH diagnosed at our institution from January 1995 to December 2010, evaluating 839 records to identify 36 patients undergoing management of tumors of the head and neck. RESULTS: Seventeen of the total 36 patients (47%; mean age 67) experienced tumor recurrence, and 10 (28%) developed metastases. Seven of nine patients initially treated with MMS (78%), and 10 of 24 (42%) treated with WLE experienced recurrence (p = .06). Patients treated with MMS had smaller tissue defects after surgery. The mean contemporary recurrence rate of MFH treated with MMS is significantly higher (58.8%) than the cumulative recurrence rate reported before 2000 (7.4%) (p < .001). CONCLUSIONS: Our study is consistent with reports of MFH as an aggressive neoplasm and describes the largest population treated with MMS in 3 decades. The changing conception of MFH, along with a propensity for in-transit metastases, may explain higher contemporary recurrence rates.

Malignant fibrous histiocytoma: changing perceptions and management challenges.

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. This review seeks to provide the practicing dermatologist with a contemporary understanding of MFH in order to guide management decisions. An extensive review of the literature was conducted using PubMed and OVID databases, searching for articles regarding MFH and undifferentiated pleomorphic sarcoma. The modern conception of MFH has changed extensively from clinical and pathologic standpoints. Limitations of the study included the reliability of past studies given the changing nature of MFH as a diagnostic entity. MFH represents an aggressive neoplasm with unique molecular, immunohistochemical, and behavioral characteristics. Practicing clinicians would benefit from a contemporary understanding of these tumors, particularly as a discussion of advances in the conception of MFH is largely absent in the dermatologic literature.