The diagnostic performance of expert dermoscopists vs a computer-vision system on small-diameter melanomas

OBJECTIVE

To evaluate the performance of dermoscopists in diagnosing small pigmented skin lesions (diameter </= 6 mm) compared with an automatic multispectral computer-vision system.

DESIGN

Blinded comparison study.

SETTING

Dermatologic hospital-based clinics and private practice offices. Patients From a computerized skin imaging database of 990 small (</= 6-mm) pigmented skin lesions, all 49 melanomas from 49 patients were included in this study. Fifty randomly selected nonmelanomas from 46 patients served as a control.

MAIN OUTCOME MEASURES

Ten dermoscopists independently examined dermoscopic images of 99 pigmented skin lesions and decided whether they identified the lesions as melanoma and whether they would recommend biopsy to rule out melanoma. Diagnostic and biopsy sensitivity and specificity were computed and then compared with the results of the computer-vision system.

RESULTS

Dermoscopists were able to correctly identify small melanomas with an average diagnostic sensitivity of 39% and a specificity of 82% and recommended small melanomas for biopsy with a sensitivity of 71% and specificity of 49%, with only fair interobserver agreement (kappa = 0.31 for diagnosis and 0.34 for biopsy). In comparison, in recommending biopsy to rule out melanoma, the computer-vision system achieved 98% sensitivity and 44% specificity.

CONCLUSIONS

Differentiation of small melanomas from small benign pigmented lesions challenges even expert physicians. Computer-vision systems can facilitate early detection of small melanomas and may limit the number of biopsies to rule out melanoma performed on benign lesions.

Analyzing complex capture-recapture data in the presence of individual and temporal covariates and model uncertainty

SUMMARY

We consider the issue of analyzing complex ecological data in the presence of covariate information and model uncertainty. Several issues can arise when analyzing such data, not least the need to take into account where there are missing covariate values. This is most acutely observed in the presence of time-varying covariates. We consider mark-recapture-recovery data, where the corresponding recapture probabilities are less than unity, so that individuals are not always observed at each capture event. This often leads to a large amount of missing time-varying individual covariate information, because the covariate cannot usually be recorded if an individual is not observed. In addition, we address the problem of model selection over these covariates with missing data. We consider a Bayesian approach, where we are able to deal with large amounts of missing data, by essentially treating the missing values as auxiliary variables. This approach also allows a quantitative comparison of different models via posterior model probabilities, obtained via the reversible jump Markov chain Monte Carlo algorithm. To demonstrate this approach we analyze data relating to Soay sheep, which pose several statistical challenges in fully describing the intricacies of the system.

Assessment of the efficacy of oral vaccination of livestock guardian dogs in the framework of oral rabies vaccination of wild canids in Israel

Since 1956, red foxes (Vulpes vulpes) and golden jackals (Canis aureus) have been the primary vectors maintaining wildlife rabies in Israel. Oral rabies vaccination of wild canids, initiated in 1998, resulted in near-elimination of the disease in wildlife by 2005. In 2005 and 2006, an outbreak of rabies was observed in stray dogs in the vaccinated area of the Golan Heights, with no cases in foxes or jackals. Epidemiological investigations showed that the infected dogs were from territories across the border. This was confirmed by molecular analysis, which showed that the virus was different from rabies isolates endemic to this area. The objective of this study was to determine bait acceptance and the feasibility of oral rabies vaccination in packs of livestock guardian dogs. Coated sachets and fishmeal polymer baits of Raboral V-RG (Merial, USA) were tested in five different test zones. Both formats were hand-fed to individual dogs and to dogs belonging to dog packs. Bait uptake and consumption were observed in each dog. The estimated efficacy of oral rabies vaccination was very low (a maximum of 28%). Vaccine delivery problems were observed in dogs belonging to packs, whereby dominant animals consumed multiple baits and in competitive situations baits were swallowed whole. The uncertainty of oral vaccination necessitated turning to other methods to control this outbreak: stray dogs were removed and herd dogs were vaccinated parenterally. This study showed that oral rabies vaccination of dogs in packs using baits designed for wildlife would not be effective. Possibly, different baits or steps to circumvent competition within the pack will make this approach feasible.

On the Bayesian estimation of a closed population size in the presence of heterogeneity and model uncertainty

We consider the estimation of the size of a closed population, often of interest for wild animal populations, using a capture-recapture study. The estimate of the total population size can be very sensitive to the choice of model used to fit to the data. We consider a Bayesian approach, in which we consider all eight plausible models initially described by Otis et al. (1978, Wildlife Monographs 62, 1-135) within a single framework, including models containing an individual heterogeneity component. We show how we are able to obtain a model-averaged estimate of the total population, incorporating both parameter and model uncertainty. To illustrate the methodology we initially perform a simulation study and analyze two datasets where the population size is known, before considering a real example relating to a population of dolphins off northeast Scotland.

A chronological perspective on suicide--the last days of life

A combined psychological autopsy and narrative approach was used to study the completed suicides of 67 Israeli soldiers. Three issues were addressed. First, the authors examined the typology of the life narratives of suicide completed during active army duty. Second, focusing on the last 3 weeks of the soldiers' lives, they sought to examine their triggers for suicide, emotional state of mind, army duty functioning, and communication of suicidal intent. Finally, they examined military responses to communication of intent, help provision, and help acceptance. Four types of narratives were identified: regressive, stable, tragic (progression and sudden collapse), and romantic (ups and downs). During the last days of life, suicide completers exhibited a split between an emotional state of mind (evidencing an emotional deterioration) and a behavioral military functioning, which was mostly stable. The analysis also revealed a resistance to receive help and a resistance to provide help, both of which impeded intervention. The gap between functioning and emotional distress in suicidal individuals and the incongruence between crisis and help are highlighted. The need to educate military personnel to look beyond duty functioning and the need to develop clear guideline about referrals to professional helps are discussed.

Primary invasive melanoma and basal cell carcinoma (collision tumor) with blue nevus-like cutaneous metastases

The simultaneous presence of two disparate neoplasms occurring in the same specimen has been well documented, albeit uncommonly. The juxtaposition of malignant melanoma and basal cell carcinoma (BCC) has been rarely reported in case reports, with most cases describing melanoma in situ and BCC. We present two cases of invasive melanoma (Clark level IV, no microscopic satellites present) intimately associated with BCC, and in areas distinction of the two lesions was difficult. Immunohistochemical studies delineated the two cell populations. In addition, one patient presented with multiple cutaneous metastases, all simulating blue nevi. The metastases occurred in the same anatomical region as the primary tumor, and histologically consisted of pigmented dendritic melanocytes and melanophages in the superficial and mid-dermis and arranged in a blue nevus-like lesion. Histologic clues suggesting the possibility of a metastatic melanoma included a sparse lymphocytic infiltrate, the presence of an epithelioid component and atypia of the dendritic melanocytes. However, without appropriate clinical history, the lesions could be overlooked as ordinary blue nevus. Collision tumors containing invasive melanoma and BCC are rare and this is the first report of a collision tumor with blue nevus-like metastasis. Awareness of this phenomenon and pattern of metastasis, together with the clinical findings will aid in the correct classification of these lesions.

Cardiorespiratory requirements of the 6-min walk test in older patients with left ventricular systolic dysfunction and no major structural heart disease

The six-minute walk test (6-MWT) is widely used to assess functional status in patients with chronic heart failure (CHF). The aims of the present study were: (1) to compare metabolic gas exchange during the 6-MWT in older patients with left ventricular systolic dysfunction (LVSD) and in breathless patients with no major structural heart disease (MSHD); (2) to determine the exercise intensity of the 6-MWT relative to peak oxygen uptake; (3) to establish the accuracy and reproducibility of the Metamax 3B ergospirometer during an incremental workload. Twenty four older patients with LVSD (19 male; age 76 +/- 5 years; BMI 27 +/- 4), and 18 patients with no MSHD (12 male; age 75 +/- 8 years; BMI 27 +/- 4) attended on consecutive days at the same time. Patients completed a 6-MWT with metabolic gas exchange measurements using the Metamax 3B portable ergospirometer, and an incremental cycle ergometry test using both the Metamax 3B and Oxycon Pro metabolic cart. Patients returned and performed a second 6-MWT and an incremental treadmill test, metabolic gas exchange was measured with the Metamax 3B. In patients with LVSD, the 6-MWT was performed at a higher fraction of maximal exercise capacity (p = 0.02). The 6-MWT was performed below the anaerobic threshold in patients with LVSD (83 %) and in patients with no MSHD (61 %). The Metamax 3B showed satisfactory to high accuracy at 10 W and 20 W in patients with LVSD (r = 0.77 - 0.97, p < 0.05), and no MSHD (r = 0.76 - 0.94, p < 0.05). Metabolic gas exchange variables measured during the 6-MWT showed satisfactory to high day-to-day reproducibility in patients with LVSD (ICC = 0.75 - 0.98), but a higher variability was evident in participants with no MSHD (ICC = 0.62 - 0.97). The Metamax 3B portable ergospirometer is an accurate and reproducible device during submaximal, fixed rate exercise in older patients with LVSD and no MSHD. In elderly patients with LVSD and no MSHD, the 6-MWT should not be considered a maximal test of exercise capacity but rather a test of submaximal exercise performance. Our study demonstrates that the 6-MWT takes place at a higher proportion of peak oxygen uptake in patients with LVSD compared to those with no MSHD, and may be one reason why fatigue is a more prominent symptom in these patients.

Multiple microcystic adnexal carcinomas

Microcystic adnexal carcinoma (MAC) is a relatively uncommon adnexal neoplasm that can demonstrate locally aggressive behavior; rare instances of metastatic lesions have been reported. We report a case of a 34-year-old black man with multiple primary MACs.

Correlations between increased erection hardness and improvements in emotional well-being and satisfaction outcomes in men treated with sildenafil citrate for erectile dysfunction

To explore relationships between erection hardness and other outcomes in men with erectile dysfunction (ED). Pooled analyses were conducted on 27 randomized, double-blind, placebo-controlled trials and six open-label trials from the worldwide sildenafil database. Outcomes included erection hardness graded subjectively, hardness and sexual satisfaction questions from the International Index of Erectile Function, general and sexually-specific emotional well-being from the self-esteem and relationship questionnaire, and the erectile dysfunction inventory of treatment satisfaction. Hardness outcomes improved (with a possible dose-response relationship for the achievement of fully hard and rigid erections) and correlated positively with the other outcomes. Sildenafil 100 mg produced optimal erection hardness (fully hard and rigid erections) in a substantial proportion of men with ED. Because optimal erection hardness correlated positively with some emotional well-being and satisfaction outcomes, sildenafil 100 mg may be the most appropriate dosage for treatment of ED for most men.

Factors influencing soay sheep survival: a Bayesian analysis

This article presents a Bayesian analysis of mark-recapture-recovery data on Soay sheep. A reversible jump Markov chain Monte Carlo technique is used to determine age classes of common survival, and to model the survival probabilities in those classes using logistic regression. This involves environmental and individual covariates, as well as random effects. Auxiliary variables are used to impute missing covariates measured on individual sheep. The Bayesian approach suggests different models from those previously obtained using classical statistical methods. Following model averaging, features that were not previously detected, and which are of ecological importance, are identified.

A novel Gypsy founder mutation, p.Arg1109X in the CMT4C gene, causes variable peripheral neuropathy phenotypes

BACKGROUND

Linkage, haplotype and sequencing analysis in a large Spanish Gypsy kindred with multiple members affected by autosomal recessive peripheral neuropathy led to the identification of a novel mutation, p.Arg1109X, in the CMT4C gene. The screening of further unrelated patients, and of a panel of ethnically matched controls, showed that p.Arg1109X is an ancestral mutation which occurs in Gypsy populations across Europe and is the most common cause of autosomal recessive Charcot-Marie-Tooth disease in Spanish Gypsies.

OBJECTIVE

To report the identification of a novel Gypsy founder mutation causing autosomal recessive CMT4C disease in a sample of homozygous affected individuals.

RESULTS

The mutation was associated with a surprisingly broad spectrum of neuropathy phenotypes, with variation in the age at onset, rate of progression, severity of muscle and sensory involvement, the presence of scoliosis, and cranial nerve involvement.

CONCLUSIONS

Ascertainment and further studies of CMT4C patients in this population will provide a unique opportunity for characterising the full range of clinical manifestations of the disease in a genetically homogeneous sample.