Pitfalls in colour photography of choroidal tumours.
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ABSTRACT:
SUBMITTER: Schalenbourg A
PROVIDER: S-EPMC3574260 | biostudies-other | 2013 Feb
REPOSITORIES: biostudies-other
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Project description:Background and aimsColour pattern is a key cue of bee attraction selectively driving the appeal of pollinators. It comprises the main colour of the flower with extra fine patterns, indicating a reward focal point such as nectar, nectaries, pollen, stamens and floral guides. Such advertising of floral traits guides visitation by the insects, ensuring precision in pollen gathering and deposition. The study, focused in the Southwest Australian Floristic Region, aimed to spot bee colour patterns that are usual and unusual, missing, accomplished by mimicry of pollen and anthers, and overlapping between mimic-model species in floral mimicry cases.MethodsFloral colour patterns were examined by false colour photography in 55 flower species of multiple highly diverse natural plant communities in south-west Australia. False colour photography is a method to transform a UV photograph and a colour photograph into a false colour photograph based on the trichromatic vision of bees. This method is particularly effective for rapid screening of large numbers of flowers for the presence of fine-scale bee-sensitive structures and surface roughness that are not detectable using standard spectrophotometry.Key resultsBee- and bird-pollinated flowers showed the expected but also some remarkable and unusual previously undetected floral colour pattern syndromes. Typical colour patterns include cases of pollen and flower mimicry and UV-absorbing targets. Among the atypical floral colour patterns are unusual white and UV-reflecting flowers of bee-pollinated plants, bicoloured floral guides, consistently occurring in Fabaceae spp., and flowers displaying a selective attractiveness to birds only. In the orchid genera (Diuris and Thelymitra) that employ floral mimicry of model species, we revealed a surprising mimicry phenomenon of anthers mimicked in turn by model species.ConclusionThe study demonstrates the applicability of 'bee view' colour imaging for deciphering pollinator cues in a biodiverse flora with potential to be applied to other eco regions. The technique provides an exciting opportunity for indexing floral traits on a biome scale to establish pollination drivers of ecological and evolutionary relevance.
| S-EPMC8577209 | biostudies-literature
Project description:OBJECTIVE:To assess the colour Doppler and ultrasound features of testicular Leydig cell tumours (LCTs) in a population of 38 surgically proven lesions. METHODS:From August 2008 to March 2015, we retrospectively included 38 surgically proven LCTs in 36 patients. Clinical data, scrotal colour Doppler, B-mode ultrasound and videos images were reviewed for each patient. The volume, echotexture of the testis, size, shape, echogenicity and the vascularization pattern of the lesion were evaluated. The tumour margins were categorized as either smooth or lobulated. The vascularization was classified as intense, moderate or without any hypervascularization. We defined the vascularization pattern groups as central, peripheral and mixed (the latter meaning both central and peripheral). RESULTS:26 patients were referred for infertility [5 patients were subsequently diagnosed with Klinefelter syndrome (KS) and 5 patients with cryptorchidism]. 28 patients underwent testis-sparing surgery, while 8 patients underwent a radical orchiectomy. The LCTs were mostly infracentimetric (68.4%), with a median size of 7.0?mm (ranging from 4.0 to 11?mm). 50% of the lesions had lobulated margins, and these were significantly larger than the smooth lesions (p?<?0.05). The content of the lesions was markedly homogeneous and hypoechoic. All lesions had sharp demarcations from the adjacent pulp. 36/38 lesions exhibited moderate-to-intense hypervascularization, with a mixed intrinsic and peripheral rim pattern. Larger lesions were more hypervascularized (p?<?0.05). LCTs in patients with KS had atypical features. CONCLUSION:Typical sporadic LCTs appeared as isolated hypoechoic, infracentimetric masses, with a clear demarcation from the adjacent pulp. They presented intrinsic and peripheral rim hypervascularization. ADVANCES IN KNOWLEDGE:By undertaking the largest imaging series of LCT to date (to our knowledge), we reassessed the typical sonographical aspects of LCTs, so as to provide guidance in regard to opting for testis-sparing surgery and for follow-up. LCTs present both intrinsic and rim vascularization detectable by colour Doppler ultrasound. Intrinsic vascularization and lobulated margins are common findings in testicular LCTs.
| S-EPMC5258179 | biostudies-other
Project description:BackgroundDiagnosis of small choroidal melanoma is mainly based on tumour thickness, subretinal fluid, or lipofuscin pigment. Ultra-wide-field imaging (UWF) allows depiction of choroidal lesions through a red (RC) and a green channel (GC). Aim of the study was to determine the utility of this tool in the detection of small choroidal melanoma.MethodsRetrospective cross-sectional study of patients with small choroidal pigmented lesions up to 3 mm in thickness. All patients underwent clinical and imaging assessment including UWF. Lesions were subcategorized based on thickness and lesion type. A qualitative assessment ensued using the red and green channels feature.ResultsA total of 152 patients were included. Melanotic naevi (76/152,50%) and small choroidal melanomas (55/152,36%) were the predominant types. Thickness was <1 mm in 30% (46/152), 1-2 mm in 46% (70/152) and 2-3 mm in 24% (36/152) of cases. Two distinct imaging patterns were noted: dark on RC/undetectable on GC and dark on RC/light on GC. In melanotic naevi the dark on RC/light on GC pattern was significantly associated with increased tumour thickness (p = 0.006) and the presence of lipofuscin (p < 0.001) suggesting a potential prognostic significance. In small melanomas such an association was not established. The majority of small melanomas manifested a dark on RC/undetectable on GC pattern despite the presence of subretinal fluid and lipofuscin.ConclusionsUWF imaging of choroidal pigmented tumours with red-green channels revealed two distinct patterns. The dark on RC/light on GC pattern was more common in suspicious melanotic naevi, but not in small melanomas. The use of red-green channels is not a reliable diagnostic tool in the early detection of small melanomas.
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Project description:ImportanceThe use of indocyanine green angiography (ICGA) is a criterion standard for diagnosing polypoidal choroidal vasculopathy (PCV), an endemic and common cause of vision loss in Asian and African individuals that also presents in white individuals. However, the use of ICGA is expensive, invasive, and not always available at clinical centers. Therefore, knowing the value of certain features detected using fundus photography (FP), optical coherence tomography (OCT), and fluorescein angiography (FA) to diagnose PCV without ICGA could assist ophthalmologists to identify PCV when ICGA is not readily available.ObjectiveTo explore the sensitivity, specificity, and predictive accuracy of potential diagnostic features detected using FP, OCT, and FA in diagnosing PCV without ICGA.Design, setting, and participantsDeidentified images of FP alone, OCT alone, and FA alone were graded by 3 retina specialists masked to ICGA findings for potentially diagnostic features of PCV prespecified before grading compared with the criterion standard grading of 2 other retina specialists with access simultaneously to FP, OCT, FA and ICGA. Specialists graded images of 124 eyes of 120 patients presenting between January 1, 2013, and December 31, 2016, with newly identified serous or serosanguinous maculopathy who had undergone FP, OCT, FA, and ICGA before treatment at a large referral eye center in Thailand.Main outcomes and measuresSensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy from the area under the receiver operating characteristic curve (AUC).ResultsThe mean (SD) age of the patients was 57.7 (12.6) years, 52 were women, 68 were men, and the diagnosis (from ICGA) was PCV for 65 eyes (52.4%), central serous chorioretinopathy for 45 eyes (36.3%), and typical neovascular age-related macular degeneration for 12 eyes (9.7%). With the use of FP, a potential diagnostic feature for PCV was notched or hemorrhagic pigment epithelial detachment (AUC, 0.77; 95% CI, 0.70-0.85). With the use of OCT, potential diagnostic features for PCV were pigment epithelial detachment notch (AUC, 0.90; 95% CI, 0.85-0.96), sharply peaked pigment epithelial detachment (AUC, 0.86; 95% CI, 0.80-0.92), and a hyperreflective ring (AUC, 0.86; 95% CI, 0.80-0.92). When at least 2 of these 4 signs were present, the AUC was 0.93 (95% CI, 0.89-0.98), with a sensitivity of 0.95 (95% CI, 0.87-0.99), a specificity of 0.95 (95% CI, 0.82-0.97), a positive predictive value of 0.92 (95% CI, 0.83-0.97), and a negative predictive value of 0.95 (95% CI, 0.86-0.99).Conclusions and relevanceThese data suggest that the potential diagnostic features detected using FP and OCT provide high sensitivity and specificity for a diagnosis of PCV, especially when at least 2 of 4 highly suggestive signs are present.
| S-EPMC6567979 | biostudies-literature
Project description:BackgroundAnimal colours and patterns commonly play a role in reducing detection by predators, social signalling or increasing survival in response to some other environmental pressure. Different colour morphs can evolve within populations exposed to different levels of predation or environmental stress and in some cases can arise within the lifetime of an individual as the result of phenotypic plasticity. Skin pigmentation is variable for many terrestrial slugs (Mollusca: Gastropoda), both between and within species. The Kerry spotted slug Geomalacus maculosus Allman, an EU protected species, exhibits two distinct phenotypes: brown individuals occur in forested habitats whereas black animals live in open habitats such as blanket bog. Both colour forms are spotted and each type strongly resembles the substrate of their habitat, suggesting that G. maculosus possesses camouflage.ResultsAnalysis of digital images of wild slugs demonstrated that each colour morph is strongly and positively correlated with the colour properties of the background in each habitat but not with the substrate of the alternative habitats, suggesting habitat-specific crypsis. Experiments were undertaken on laboratory-reared juvenile slugs to investigate whether ultraviolet (UV) radiation or diet could induce colour change. Exposure to UV radiation induced the black (bog) phenotype whereas slugs reared in darkness did not change colour. Diet had no effect on juvenile colouration. Examination of skin tissue from specimens exposed to either UV or dark treatments demonstrated that UV-exposed slugs had significantly higher concentrations of black pigment in their epithelium.ConclusionsThese results suggest that colour dimorphism in G. maculosus is an example of phenotypic plasticity which is explained by differential exposure to UV radiation. Each resulting colour morph provides incidental camouflage against the different coloured substrate of each habitat. This, to our knowledge, is the first documented example of colour change in response to UV radiation in a terrestrial mollusc. Pigmentation appears to be correlated with a number of behavioural traits in G. maculosus, and we suggest that understanding melanisation in other terrestrial molluscs may be useful in the study of pestiferous and invasive species. The implications of colour change for G. maculosus conservation are also discussed.
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Project description:The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d') and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain.
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