Absence Of Pigment Research Articles

Report of leucism in tadpoles of Ceratophrys stolzmanni (Amphibia, Anura, Ceratophryidae) in laboratory

ABSTRACT We report the first cases of leucism in Ceratophrys stolzmanni larvae. The leucistic individuals were recorded in an ex-situ population for conservation and research of the species, within the Conservation Initiative for Threatened Amphibians “Balsa de los Sapos” [Raft for Frogs] at the Pontificia Universidad Católica del Ecuador. These individuals presented different color traits from those of the same cohort and as they grew older their uniform white coloration was defined. The leucistic individuals died as tadpoles, after time periods that exceeded the ones reported and recorded for ending metamorphosis in the species, suggesting a link between the absence of pigmentation and a potential malfunction of the thyroid gland.

Determination of the melanin and anthocyanin content in barley grains by digital image analysis using machine learning methods.

The pigment composition of plant seed coat affects important properties such as resistance to pathogens, pre-harvest sprouting, and mechanical hardness. The dark color of barley (Hordeum vulgare L.) grain can be attributed to the synthesis and accumulation of two groups of pigments. Blue and purple grain color is associated with the biosynthesis of anthocyanins. Gray and black grain color is caused by melanin. These pigments may accumulate in the grain shells both individually and together. Therefore, it is difficult to visually distinguish which pigments are responsible for the dark color of the grain. Chemical methods are used to accurately determine the presence/ absence of pigments; however, they are expensive and labor-intensive. Therefore, the development of a new method for quickly assessing the presence of pigments in the grain would help in investigating the mechanisms of genetic control of the pigment composition of barley grains. In this work, we developed a method for assessing the presence or absence of anthocyanins and melanin in the barley grain shell based on digital image analysis using computer vision and machine learning algorithms. A protocol was developed to obtain digital RGB images of barley grains. Using this protocol, a total of 972 images were acquired for 108 barley accessions. Seed coat from these accessions may contain anthocyanins, melanins, or pigments of both types. Chemical methods were used to accurately determine the pigment content of the grains. Four models based on computer vision techniques and convolutional neural networks of different architectures were developed to predict grain pigment composition from images. The U-Net network model based on the EfficientNetB0 topology showed the best performance in the holdout set (the value of the "accuracy" parameter was 0.821).

STAIN FUNGI CONTROL IN PINUS SP. WOOD WITH SILICA MESOPOROUS PARTICLES LOADED WITH ESSENTIAL OILS

The use of essential oils (EO) carried onto mesoporous silica particles (MSPs) was tested to control pinewood stains. Three types of MSPs were synthesizedand physicochemically characterized with N2physisorption (type IV), X-ray diffraction [Miller indices (100), (110), (200)], scanning electron microscopy, zeta potential (negative values), dynamic light scattering (< 200 nm) and thermogravimetric analysis(5% to 10% weight loss). A response surface design was used to find the EO loading conditions to control stain, the latter was measured as colour change with the CIEDE2000formula. The essential oil loading onto MSPC was physicochemically confirmed by a weight loss of 47% in the thermogravimetric analysis. TheCitrus, Syzygiumsp. and Tagetessp. oils carried onto mesoporous particles MSPC (30:1 w/w) controlled the pinewood stain caused by Alternaria sp. andGeosmithia sp. This was demonstrated by the absence of pigmentation and scarce fungal growth.

Prognostic biomarkers for survival in mucosal melanoma.

Mucosal melanoma (MM) is a rare subtype of melanoma with an aggressive clinical course. In cutaneous melanoma (CM), the absence of pigmentation and presence of NRAS/KRAS mutations are biomarkers indicating an aggressive clinical course with shorter overall survival. Similar data for MM are missing. We present the real-world outcome data in a cohort of genotyped MM patients and assessed the prognostic relevance of pigmentation- and NRAS/KRAS mutation status. We correlated pathological reports and clinical data with overall survival of patients with MM. Furthermore, we performed clinically integrated molecular genotyping and analyzed real world treatment regimens for covariates associated with clinical outcome. We identified 39 patients with available clinical and molecular data. Patients with amelanotic MM had a significantly shorter overall survival (p = .003). In addition, the presence of a NRAS or KRAS mutation was significantly associated with poor overall survival (NRAS or KRAS p = .024). Currently, it is unknown if the same prognostic relevance for the lack of pigmentation and RAS mutations in CM, exists in MM. Here we analyzed a cohort of MM for outcome measures and determined that two known prognostic biomarkers for CM are in fact novel prognosticators for MM.

Prognostic biomarkers for survival in mucosal melanoma.

e21576 Background: Mucosal Melanoma is a rare subtype of melanoma with a more aggressive clinical course when compared to cutaneous melanoma. In cutaneous melanoma, the absence of pigmentation and presence of NRAS/KRAS mutations are known as biomarkers indicating an aggressive clinical course with significantly shorter overall survival times. Similar data for mucosal melanoma are currently missing. Here, we present real world outcome data in a large cohort of genotyped mucosal melanoma patients and assessed the prognostic relevance of pigmentation- and NRAS/KRAS mutation status. Methods: We correlated pathological reports and clinical data with overall survival of patients with mucosal melanoma. Furthermore, we performed clinically integrated molecular genotyping and analyzed real world treatment regimens for covariates associated with clinical outcome. For institutional data analysis, we ran a source query and only included patients with the diagnosis of mucosal melanoma, available genotyping data and comprehensive clinical information. As a population-based reference and to directly compare overall survival differences we first queried the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database. Pigmentation status was assessed by pathological review. Treatment regimens were identified by chart review. Results: We identified a cohort of 39 patients with mucosal melanoma where clinical and molecular data was available. Patients with amelanotic mucosal melanoma had a significantly shorter overall survival ( p = 0.003). In addition, the presence of a NRAS or KRAS mutation was significantly associated with poor overall survival (NRAS or KRAS p = 0.024). Therapeutic regimens were heterogeneous with a mean of 5 treatment lines per patient. Patients with low stage tumors who received immunotherapy had a significantly shorter overall survival (p < 0.001), although numbers were small. Conclusions: The absence of pigmentation and the presence of NRAS or KRAS mutations are poor prognostic indicators for survival in CM. Both biomarkers are have been described in MM. Currently, it is unknown if the same prognostic relevance for the lack of pigmentation and RAS mutations exists in MM. Here we analyzed a cohort of MM for outcome measures and determined that two known prognostic biomarkers for CM are in fact novel prognosticators for MM.

The double jeopardy of women with albinism in Ibadan, Nigeria: breaking the unemployment barrier

Albinism is an inherited genetic condition, which results in a decrease or absence of pigmentation in the hair, eyes, and skin. Studies on albinism in Africa have focused on a wide range of themes with little or no effort to capture the unique experiences of women with albinism, particularly in relation to their unemployment challenges. Here, we explore the unemployment challenges of women with albinism in Ibadan, southwest Nigeria. We found that rejection based on skin color, prejudicial notion that women with albinism have body odor, general notion of their incompetence because of impaired eyesight, and stereotypical adherence to myths that albinism is bad all contribute to their exclusion from the labor force. We conclude that women with albinism in Ibadan experience double jeopardy of economic marginalization and livelihood deprivation due to their condition of albinism on one hand, and their being women, on the other hand.

Unusual Variant of Cutaneous Amelanotic Melanoma of the Cheek

Amelanotic melanoma is a type of cutaneous melanoma characterized by the absence of pigment. The rhabdoid features are an uncommon histological variant of malignant melanoma. Only a handful of primary rhabdoid melanoma cases have been reported in the literature.

Mechanisms underlying albinism as a consequence of ommochrome deficiency in cave isopods

Albinism, or loss of pigment, is a typical adaptation to living in caves and occurs in numerous cave dwellers. To understand the evolution of this trait, one must identify the type of biological pigment present in the phylogenetically closest surface relatives. The absence of pigmentation has been studied primarily in terms of melanin deficiency, while the exact mechanism of ommochrome loss in any cave dwellers is largely unknown. Ommochromes are tryptophan derivatives and generally belong to a less studied class of biological pigments previously described in protostomes such as isopod crustaceans. Using a simple method for extraction and detection of ommochromes in conjunction with liquid chromatography coupled with mass spectrometry (UPLC-MS), we characterized the nature of pigments in surface isopods. We detected, for the first time and to the best of our knowledge, ommochromes in three groups of surface isopods: the families Sphaeromatidae (Flabellifera) and Trichoniscidae (Oniscidea) and the genus Proasellus (Asellota). To determine which step of the ommochrome production pathway is disrupted in cave isopods, we quantified the precursors of ommochrome synthesis in closely related surface and cave species. Our results suggest that the disruption of ommochrome synthesis is preferentially located at the beginning of this anabolic cascade, as we observed an accumulation of the precursor tryptophan in albino species. To address this problem at the molecular level, we are trying to determine the exact genes and mutations that may be involved in the loss of ommochromes. We performed RNA-seq on two representatives of surface and cave species of the genus Proasellus and analyzed the data for expression changes in candidate genes.

Pre-sintering pigmentation techniques do not affect the fatigue behavior of adhesively luted 4YSZ restorations

This study aims to characterize the effect of shading techniques on the fatigue behavior of a 4YSZ ceramic (4 mol% yttrium stabilized zirconia) adhesively bonded to a dentin analogue (fiber-reinforced epoxy resin). 4YSZ ceramic discs (IPS e.max ZirCAD, Ø = 10 mm and 1 mm of thickness) were allocated according to the factor ‘shading technique’ into 4 groups: Brush– unshaded ceramic disc (IPS e.max ZirCAD BL) pigmented at the pre-sintered stage with pigment solution applied manually using a round liner brush; Immersion– unshaded ceramic disc pigmented through immersion in the solution for 1 s on only one side of the ceramic disc; Manufacturer– specimens already shaded by the manufacturer (IPS e.max ZirCAD MT A2 – Manufacturer group); Control– a control condition with absence of pigment (i.e. non-pigmented specimens). The specimens were sintered and a spectrophotometer (SP60, EX- Rite) was used to ensure that the same perceived color (i.e. pigment saturation) was achieved in the different shading strategies (Manufacturer, Brush or Immersion groups). To do so, the color differences (ΔE00) were calculated using the CIEDE 2000 equation; and an ΔE00 of up to 1.77 was considered as an acceptability threshold. Dentin analogue discs were obtained (Ø = 10 mm and 2.5 mm of thickness) and randomly allocated into pairs with the 4YSZ ceramic discs. Next, the pairs were adhesively bonded using a resin cement (Multilink N). The bonded assemblies (n = 15) were tested for fatigue using the step-stress test method (frequency of 20 Hz; 10,000 cycles per step, initial load 200 N; step-size of 100 N, up to 700 N; and after, step-size of 50 N, until specimen failure/fracture or radial cracks). Fatigue failure load (FFL) and number of cycles for failure (CFF) were recorded for statistical analysis. Fractographic features were accessed, and complementary roughness, topography, grain size and phase content analyses were performed. No statistical differences were observed in the fatigue behavior among the non-shaded condition (Control group – 880 N) and the shaded specimens (Manufacturer – 887 N, Brush – 820 N, and Immersion – 850 N groups; p > 0.05). However, the use of a brush shading technique induced slightly inferior fatigue mechanical behavior of the restorative set compared to the specimens already shaded by the manufacturer (p = 0.027). No differences in Weibull modulus were observed among the tested groups. The specimens pigmented by the brush technique demonstrated a rougher surface, with statistically higher Rz values, in addition to a larger grain size in comparison to all other conditions (p< 0.05). No m-phase content was identified (only t and c phases were detected). Thus, the shading techniques used to provide a Vita classic A2 shade does not negatively affect the mechanical fatigue properties of a bonded 4YSZ ceramic. However, the brush technique has detrimental effect on the fatigue behavior compared to when the ceramic was already provided in a shaded format by its manufacturer.

ATYPICAL MELANOMA MIMICKING A VASCULAR TUMOR : CLINICAL AND DERMOSCOPIC FINDINGS

Introduction: Completely amelanotic melanomas are rare and therefore often misdiagnosed. Analysis of dermoscopic features of the vascular pattern appears to be a reliable method to suggest these particular diagnosis. Case Presentation: we report a case of an atypical primary cutaneous melanoma of plantar localization which clinically mimicked an angiomatous tumor. Clinical examination showed an angiomatous lesion of 10 cm long axis, located on the lateral part of the left sole. The two adjacent nodules measured 3 cm each, one was angiomatous and the other erythematous. There were also multiple left inguinal adenopathies. Dermoscopic evaluation of the lesion revealed the lack of a pigmented network and a rich vascular bundle made of polymorphous linear vessels, dotted vessels, white lines and milky red areas. The patient underwent excision of an angiomatous nodule. The definitive diagnosis was provided by immunohistochemistry (tumor cells expressed S100 and Melan A). . Brain and thoracic-abdominal-pelvic CT scan showed bilateral nodular lung involvement and a segment VI liver lesion. We concluded to the diagnosis of a primary amelanotic metastatic melanoma stage 4. Clinical Discussion: The term amelanotic refers to tumors that have no pigmentation on visual and dermoscopic inspection. Amelanotic and hypomelanotic melanomas are rare. They could mimic many benign and malignant tumors. There are three forms of AM. The papulonodular form represents 58% and could be misdiagnosed as a vascular tumor, which was the case of our patient. The contribution of dermoscopy is valuable in the clinical orientation in case of amelanotic melanoma. There is a correlation between the stage of the melanoma and the vascular pattern(s) observed as well as their distribution. The prognosis of amelanotic melanoma is characterized with a lower survival rate and a high risk of recurrence. The treatment of amelanotic melanoma is similar to the pigmented counterpart. Conclusion: In order to avoid therapeutic delay, melanoma should be considered whenever there is a suspicious plantar lesion even in the absence of pigmentation. Dermoscopy is a non-invasive technique that could help in the diagnosis.

Genome-Wide Association Study of Pericarp Color in Rice Using Different Germplasm and Phenotyping Methods Reveals Different Genetic Architectures.

Pericarp colors (PC) in rice are determined by the types and content of flavonoids in the pericarp. The flavonoid compounds have strong antioxidant activities and are beneficial to human health. However, the genetic basis of PC in rice is still not well-understood. In this study, a genome-wide association study (GWAS) of PC was performed in a diverse rice collection consisting of 442 accessions using different phenotyping methods in two locations over 2 years. In the whole population consisting of white and colored pericarp rice, a total of 11 quantitative trait loci (QTLs) were identified using two phenotyping methods. Among these QTLs, nine were identified using the phenotypes represented by the presence and absence of pigmentation in pericarp, while 10 were identified using phenotypes of the degree of PC (DPC), in which eight are common QTLs identified using the two phenotyping methods. Using colored rice accessions and phenotypes based on DPC, four QTLs were identified, and they were totally different from the QTLs identified using the whole population, suggesting the masking effects of major genes on minor genes. Compared with the previous studies, 10 out of the 15 QTLs are first reported in this study. Based on the differential expression analysis of the predicted genes within the QTL region by both RNA-seq and real-time PCR (RT-PCR) and the gene functions in previous studies, LOC_Os01g49830, encoding a RAV transcription factor was considered as the candidate gene underlying qPC-1, a novel QTL with a large effect in this study. Our results provide a new insight into the genetic basis of PC in rice and contribute to developing the value-added rice with optimized flavonoid content through molecular breeding.

Designing Multicolor Graphics of Plasmonic Metasurfaces through Gradual Protrusion of Particles at Free Interface

AbstractMetal nanostructures show plasmonic colors in the absence of pigments, which are promising for various optical applications. Colloidal lithography is one of the cost‐effective methods for a wide‐area production of plasmonic metasurfaces. However, it remains an important challenge to regioselectively control plasmonic property in a facile and reliable manner. Here, a novel strategy is reported to produce multicolor plasmonic graphics using the gradual protrusion of colloids at a water‐resin interface. Particles anchored at free interfaces slowly migrate toward the equilibrium position. Therefore, the degree of protrusion into the opposite phase is determined by the duration of aging. With this phenomenon, dimple arrays with controlled depths is produced by capturing the particles at the water‐resin interface through photopolymerization and removing the particles. Directional deposition of aluminum on the dimple arrays renders plasmonically colored surfaces, where the resonant wavelengths, or colors, vary with dimple depth. As the resin is regioselectively photocurable by ultraviolet irradiation through photomasks, plasmonic graphics can be produced. In addition, multi‐steps of regioselective photocuring with controlled durations of incubation produce multicolor graphics. The graphics show consistent plasmonic colors for specular reflection while displaying iridescent diffraction colors from hexagonal arrays of dimples for off‐specular conditions, enhancing the visibility of graphics.

The Absence of Abdominal Pigmentation in Livestock Associated Culicoides following Artificial Blood Feeding and the Epidemiological Implication for Arbovirus Surveillance.

Culicoides midges (Diptera: Ceratopogonidae), the vectors of economically important arboviruses such as bluetongue virus and African horse sickness virus, are of global importance. In the absence of transovarial transmission, the parity rate of a Culicoides population provides imperative information regarding the risk of virus dispersal. Abdominal pigmentation, which develops after blood feeding and ovipositioning, is used as an indicator of parity in Culicoides. During oral susceptibility trials over the last three decades, a persistent proportion of blood engorged females did not develop pigment after incubation. The present study, combining a number of feeding trials and different artificial feeding methods, reports on this phenomenon, as observed in various South African and Italian Culicoides species and populations. The absence of pigmentation in artificial blood-fed females was found in at least 23 Culicoides species, including important vectors such as C. imicola, C. bolitinos, C. obsoletus, and C. scoticus. Viruses were repeatedly detected in these unpigmented females after incubation. Blood meal size seems to play a role and this phenomenon could be present in the field and requires consideration, especially regarding the detection of virus in apparent “nulliparous” females and the identification of overwintering mechanisms and seasonally free vector zones.

Fine morphological and histological characteristics of Placobdelloides siamensis (Annelida: Glossiphoniidae)

The Siamese shield leech (Placobdelloides siamensis) is one of the external parasites found in snail-eating turtles (Malayemys macrocephala and Malayemys subtrijuga). It has a muscular proboscis with numerous needle-like tips for penetrating the host body, and its consumption of blood and tissues differs from arhynchobdellid leeches that use a jaw tearing strategy. Dorsal coloration is attributed to pigment cells under the dorsal muscular layer, while the absence of pigment on the ventral side indicates transparency. Morphology and histology reveal the parental care behavior of this glossiphoniid leech, with the juveniles using their caudal sucker to attach an annulus around the ventral groove of the parent. Further, the histological structure of the posterior part demonstrates the presence of four contributing muscle fibers and chloragogen cells on the caudal sucker. Hence, this first report provides increasing morphological and histological knowledge of this leech for use as a representative model of a glossiphoniid leech.

Vulvar vitiligo and lichen sclerosus in children: A clinical challenge.

Vulvar vitiligo (VV) and vulvar lichen sclerosus (VLS), both feature skin and mucosal hypo-/depigmentation. The aim of this study was to describe the clinical and dermoscopic features of VV and VLS in the pediatric population, providing diagnostic clues, and to define their association. We performed a systematic literature review of the clinical and dermoscopic features of pediatric VV and VLS. An observational study was conducted on children affected by VLS associated with VV, referred to the Dermatology Unit of the Sant'Orsola Polyclinic in Bologna, Italy. Medical history, age at diagnosis, ethnicity, clinical and dermoscopic features, and symptoms were recorded for all patients. 124 cases of VLS and 10 cases of VV were reviewed. Clinical manifestations included hypo-/depigmented patches in both conditions, while ecchymosis/purpura and fissures/erosion were observed in VLS. Symptoms including pruritus, pain, or burning were reported only by VLS patients. In our study five patients with VLS associated with VV were retrieved. Clinical features included well-demarcated depigmented patches in VV and translucent areas, erythema, ecchymoses/purpura, and labial fusion in VLS. Dermoscopy showed white structureless areas with a whipped cream-like appearance, linear or dotted vessels, white chrysalis-like structures, erosion and red-purpuric blotches in VLS and reduced pigment network or pigment absence, intralesional spots of residual pigmentation and telangiectasias in VV. Symptoms were present in all patients. Both VV and VLS show hypo-/depigmented patches. In the presence of associated symptoms, possible VLS should be investigated with clinical and dermoscopic examination to achieve a prompt diagnosis.

EXCLUSION IN INCLUSION: EXPERIENCES OF LEARNERS WITH ALBINISM IN SELECTED MAINSTREAM AND SPECIAL SCHOOLS IN ZAMBIA

Albinism is an inherited skin pigmentation condition which affects all races in the world. However, the condition is more conspicuous among the black population because of the absence of pigmentation which leads to some whitish appearance. This condition also leads to multiple disabling experiences to the individuals with albinism. The overriding aim of the study was to establish the learning experiences of learners with albinism in both regular and special schools. The study was located within an interpretive qualitative paradigm and used a phenomenology research design. The Interpretive Phenomenological Analysis (IPA) was used to explore in detail how participants made sense of their personal and social world with regard to learners with albinism in regular and special schools. The researchers conducted one-on-one interviews with the participants and content – analyzed the data. Parents of learners with albinism, teachers, school administrators and learners with albinism participated in interviews. The findings revealed that in regular schools’ learners with albinism tended to exclude themselves from other learners so as to avoid discrimination and stereotypes surrounding their condition. The findings also confirmed the existence of myths and stereotypes regarding albinism. The findings further revealed that teachers in regular schools were not patient with learners with albinism and did not give them extra attention and that some teachers used negative comments and did not want learners with albinism in their classes. It was observed that the majority of learners with albinism felt more secure in special schools rather than regular schools. Parents of children with albinism supported the idea of learners with albinism learning in special schools where the learning environment was conducive for them. The study recommended inter alia that government through the Ministry of Education should enhance teacher education programmes by providing requisite knowledge and skills to trainee and serving teachers on handling learners with albinism and other disabilities. School administrators, teachers, learners and the community should raise sensitization and awareness campaigns on disability issues.&#x0D; &#x0D; &lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/edu_01/0790/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Melanocytic Lesions- A Hospital-based Descriptive Study from Central Kerala, India

Introduction: Malignant melanoma is a tumour of melanocytic origin. There is considerable geographic variation in the incidence of melanocytic lesions and are related to exposure to sunlight and susceptibility of the population. Descriptive and statistical studies of melanocytic lesions are few among Indian populations. Aim: To describe and categorise melanocytic lesions, analyse their histological features and form evidence based data applicable to Indian population. Materials and Methods: The present descriptive study was conducted in Department of Pathology in a tertiary care centre in central Kerala, India from August 2013 to July 2016. Total duration of the study was 36 months starting from 2013 August to 2016 July. Melanocytic lesions received in Pathology Department for the study period were analysed. Data including age, gender, signs and symptoms, anatomical site, clinical and gross photographs were analysed. For each case, gross and histopathological examination were done. In some cases histopathological study alone was not diagnostic, so Immunohistochemistry (IHC) including Human Melanoma Black (HBM)-45 and Melan-A were conducted to establish melanocytic differentiation. Final statistical analysis was done by frequency measurements and cross tabulation using Statistical Package for the Social Sciences (SPSS) software version 17.0. Results: Total sample size was 57, among which 44 cases were from cutaneous sites (27 benign and 17 malignant) and 13 were from mucosal sites (2 benign and 11 malignant). Most of the cases were from above 60 years age group (35%). Anatomically, majority of cutaneous melanomas were from lower limb {15 (88.2%)} and majority of mucosal melanomas were from upper gastrointestinal tract {5 (38.4%)}. Although prominent nucleoli are said to be characteristic feature of melanomas, 8 out of the 28 total cases of melanomas had inconspicuous nucleoli (28.5%). When cell morphology of melanomas was studied, majority of cases had oval cells 10 (35.7%). It was also found that there was a significant correlation between spindle cell morphology and absence of pigment in melanomas (p-value=0.004). There was no association between mitosis in melanomas and vertical tumour diameter (p-value=0.1837). Conclusion: A female predominance was observed and the commonly effected age group was above 60 years. Intradermal nevi were the major benign melanocytic lesion, while the common site was lower limb among cutaneous melanomas and upper gastrointestinal tract among mucosal melanomas. A positive association between absence of pigment in malignant melanomas and predominance of spindle cells was found.

Features associated with melanoma metastasis in Latvia.

Cutaneous melanoma (CM) is the most aggressive form of skin cancer, exhibits an increasing incidence worldwide and has a high potential to develop metastasis. The current study aimed to identify a set of parameters that may aid in predicting the probability and timing of the onset of CM metastasis. A retrospective analysis was performed using the archive data of 2,026 patients with CM that were treated at the Riga East University Hospital Latvian Oncology Centre, which is the largest oncological hospital in the country, between 1998 and 2015. A case-control study design was employed, where patients with metastasis (n=278) were used as the cases and patients without metastasis were used as the controls. The present study examined the associations between metastasis and potential risk factors and constructed multivariate models of features that predicted metastasis using stepwise regression. Time until metastasis was analyzed using negative binomial regression models. The results of the present study indicated an increase in the number of melanomas that developed metastases during 1998–2015. Tumor Breslow thickness was demonstrated to be significantly larger in patients with metastasis compared with those without (P=0.012). The presence of ulceration significantly increased the risk of metastases [odds ratio (OR), 1.66; 95% CI, 1.07-2.59; P=0.033]. The absence of pigment in melanoma tissues was indicated to lead to a greater likelihood of metastasis (OR, 2.14; 95% CI, 1.10-4.19; P=0.035). Shorter times from diagnosis until the onset of metastases were observed in older patients (incident rate ratio (IRR), 6.85; 95% CI, 2.43-19.30; P=2.78×10−4), and a borderline significant association was observed in those with ulcerated tumors (IRR, 1.33; 95% CI, 0.98-1.80; P=0.064). Therefore, the main features associated with the development of melanoma metastasis in Latvia were indicated to be tumor ulceration, absence of pigment and Breslow thickness.

A New Species of Rhynchohyalus from the Southeastern Pacific Ocean with Notes on R. natalensis (Opisthoproctidae)

A new species Rhynchohyalus parbevs sp. nov. from the Southeast Pacific, which differs from R. natalensis in the greater number of gill rakers, the relative position of the fins, and the absence of pigmentation of the adipose fin. Based on our own and literature data, the variability of a number of diagnostically significant characters in R. natalensis was discussed. The capture of this species in the Indian Ocean is reported for the first time.

Influence of light and kairomone baiting systems on trap collections of biting midges in southern Sweden.

Effective surveillance is essential for protecting livestock from Culicoides biting midges and the viruses they transmit. The objective of this study was to determine how the baiting system used in traps (UV, incandescent light, incandescent light with CO2 , and incandescent light with CO2 and 1-octen-3-ol) influences estimates of midge population abundance, parity, and diel activity. This was achieved through a standardized trapping protocol conducted in three habitats in Sweden. UV light traps caught the most Culicoides species and more C. obsoletus complex females than incandescent light traps. Traps baited with CO2 plus 1-octen-3-ol caught more female C. impunctatus than incandescent light traps. No consistent effect of bait type was found on C. obsoletus parity rate, as estimated from the proportion of midges with presence or absence of pigmentation. Midge activity, as reflected by trap catches, peaked between -3 h and +3 h relative to sunset, with UV traps catching significantly more female C. obsoletus complex and C. impunctatus at and after sunset than before sunset. We conclude that baiting system can influence biting midge collections, even using identical traps. Effective surveillance may require more than one bait type and kairomones to attract species that do not feed exclusively on cattle.