Disentangling the Impact of Point Defect Density and Carrier Localization-Enhanced Auger Recombination on Efficiency Droop in (In,Ga)N/GaN Quantum Wells.

The internal quantum efficiency of (In,Ga)N/GaN quantum wells can surpass 90% for blue-emitting structures at moderate drive current densities but decreases significantly for longer emission wavelengths and at higher excitation rates. This latter effect is known as efficiency "droop" and limits the brightness of light-emitting diodes (LEDs) based on such quantum wells. Several mechanisms have been proposed to explain efficiency droop including Auger recombination, both intrinsic and defect-assisted, carrier escape, and the saturation of localized states. However, it remains unclear which of these mechanisms is most important because it has proven difficult to reconcile theoretical calculations of droop with measurements. Here, we first present experimental photoluminescence measurements extending over three orders of magnitude of excitation for three samples grown at different temperatures that indicate that droop behavior is not dependent on the point defect density in the quantum wells studied. Second, we use an atomistic tight-binding electronic structure model to calculate localization-enhanced radiative and Auger rates and show that both the corresponding carrier density-dependent internal quantum efficiency and the carrier density decay dynamics are in excellent agreement with our experimental measurements. Moreover, we show that point defect density, Auger recombination, and the effect of the polarization field on recombination rates only limit the peak internal quantum efficiency to about 70% in the resonantly excited green-emitting quantum wells studied. This suggests that factors external to the quantum wells, such as carrier injection efficiency and homogeneity, contribute appreciably to the significantly lower peak external quantum efficiency of green LEDs.

Heterogeneous addiction to transforming growth factor-beta signalling in recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is associated with a high mortality rate due to the development of life-threatening, metastatic cutaneous squamous cell carcinoma (cSCC). Elevated transforming growth factor-beta (TGF-ß) signalling is implicated in cSCC development and progression in patients with RDEB. OBJECTIVES: To determine the effect of exogenous and endogenous TGF-ß signalling in RDEB cSCC with a view to assessing the potential of targeting TGF-ß signalling for RDEB cSCC therapy. METHODS: A panel of 11 patient-derived RDEB cSCC primary tumour keratinocyte cell lines (SCCRDEBs) were tested for their signalling and proliferation responses to exogenous TGF-ß. Their responses to TGF-ß receptor type-1 (TGFBR1) kinase inhibitors [SB-431542 and AZ12601011 (AZA01)] were tested using in vitro proliferation, clonogenicity, migration and three-dimensional invasion assays, and in vivo tumour xenograft assays. RESULTS: All SCCRDEBs responded to exogenous TGF-ß by activation of canonical SMAD signalling and proliferative arrest. Blocking endogenous signalling by treatment with SB-431542 and AZ12601011 significantly inhibited proliferation (seven of 11), clonogenicity (six of 11), migration (eight of 11) and invasion (six of 11) of SCCRDEBs. However, these TGFBR1 kinase inhibitors also promoted proliferation and clonogenicity in two of 11 SCCRDEB cell lines. Pretreatment of in vitro TGFBR1-addicted SCCRDEB70 cells with SB-431542 enhanced overall survival and reduced tumour volume in subcutaneous xenografts but had no effect on nonaddicted SCCRDEB2 cells in these assays. CONCLUSIONS: Targeting TGFBR1 kinase activity may have therapeutic benefit in the majority of RDEB cSCCs. However, the potential tumour suppressive role of TGF-ß signalling in a subset of RDEB cSCCs necessitates biomarker identification to enable patient stratification before clinical intervention.

A systematic review of pharmacological therapies and their effectiveness on health-related quality of life outcomes in patients with juvenile-onset systemic lupus erythematosus.

Juvenile-onset systemic lupus erythematosus (JSLE) presents with an aggressive course and high morbidity associated with disease and treatment. JSLE patients have a poorer health-related quality of life (HRQoL) when compared with age-matched patients with other rheumatologic disorders. We aim to summarize the impact of current pharmacological therapies on the HRQoL of JSLE patients. Search strategies were developed across seven databases. Randomized clinical trials (RCTs) and cohort studies comparing interventions to standard therapy, placebo or pre-post cohort comparisons for more than 4 weeks were included. The outcome included self-reported scales compared at baseline and a therapeutic time point. Risk of bias was evaluated by using the Cochrane risk of bias tool and the Newcastle-Ottawa quality assessment scale. A total of 2812 articles were narrowed down to 309 for full-text screening. Four RCTs and one prospective cohort study, with a total of 634 JSLE patients, met the inclusion criteria. Four of the studies had a controlled intervention plus standard therapy compared with standard therapy alone or placebo. Multiple indices were used to evaluate HRQoL. These included the Pediatric Quality of Life Inventory, Childhood Health Assessment Questionnaire, Simple Measure of Impact of Lupus Erythematosus in Youngsters tool, Kids Fatigue Severity Scale and Child Depression Inventory. A single study reported a significant improvement while remaining studies reported no difference or failed to report the statistical analysis. Although HRQoL is significantly impaired in JSLE, evidence regarding its improvement is limited due to the small number of eligible studies, heterogeneity in scales, and HRQoL domains. A universal HRQoL questionnaire for JSLE needs to be established and used in both the research and clinical setting. All studies should adhere to reporting guidelines.

Seven novel COL7A1 mutations identified in patients with recessive dystrophic epidermolysis bullosa from Mexico.

Recessive dystrophic epidermolysis bullosa (RDEB; OMIM #226600) is one of the most devastating subtypes of epidermolysis bullosa, a group of skin and mucous membrane blistering disorders often associated with extracutaneous manifestations. RDEB is caused by mutations in COL7A1, the gene encoding type VII collagen (C7), and to date over 700 different mutations in the 8835 nucleotides constituting the open reading frame or adjacent exon-intron boundaries of COL7A1 have been described. We used targeted next-generation sequencing to identify seven previously unreported mutations in a cohort of 17 Mexican patients who were diagnosed with RDEB based on clinical presentation and immunoepitope mapping. Our study expands the spectrum of mutations identified in this cohort, including those suitable for emerging therapies reliant on precise genotyping.

Management of cutaneous squamous cell carcinoma in patients with epidermolysis bullosa: best clinical practice guidelines.

This article summarizes recommendations reached following a systematic literature review and expert consensus on the diagnosis and management of cutaneous squamous cell carcinomas in people with epidermolysis bullosa. The guidelines are intended to help inform decision making by clinicians dealing with this complex complication of a devastating disease.

Clinical features of gingival lesions in patients with dystrophic epidermolysis bullosa: a cross-sectional study.

BACKGROUND: Gingival lesions in patients with dystrophic epidermolysis bullosa (DEB) are a common manifestation. However, their clinical features, frequency and severity are currently unknown. METHODS: Forty-five DEB patients were assessed by an oral medicine specialist, who analysed the presence/absence of four clinical signs (erythema, erosion/ulcer, atrophy, blister) on free and attached gingiva, using the Epidermolysis Bullosa Oropharyngeal Severity score. RESULTS: Twenty-eight (62.2%) out of 45 DEB patients showed different types of gingival lesions, whose presence/absence and total frequency/distribution were not significantly different between males and females (p=0.087 and p=0.091, respectively). Erythema was the most prevalent lesion (66.2%) and the recessive DEB severe generalized (RDEB-sev gen) reached the highest median disease activity score. A significant correlation was observed between the DEB subtypes and the disease activity median score (p<0.001), but not between age and total disease activity score in each group of DEB (p>0.05). Lastly, logistic regression showed that only gender (p=0.031) and RDEB-sev gen (p=0.001) were risks factors for the presence of gingival lesions. CONCLUSIONS: Gingival lesions in DEB patients are a relatively common entity and may have multiple clinical aspects, emphasizing the need for thorough attention and awareness among dentists.

High levels of type VII collagen expression in recessive dystrophic epidermolysis bullosa cutaneous squamous cell carcinoma keratinocytes increases PI3K and MAPK signalling, cell migration and invasion.

BACKGROUND: Epidermolysis bullosa is a group of inherited skin fragility diseases varying in severity from mild scarring to infant mortality. Great efforts are being undertaken to develop therapeutic strategies to treat the more pernicious forms of this disease, particularly those associated with recessive, loss-of-function mutations. In such cases significant effort is directed toward delivering recombinant protein at levels sufficient to demonstrate clinical benefit. Recessive dystrophic epidermolysis bullosa (RDEB) predisposes patients to a high incidence of life-threatening cutaneous squamous cell carcinoma (cSCC). Mutations in the gene encoding type VII collagen, COL7A1, are the sole cause of this disease and conflicting reports concerning type VII collagen and COL7A1 in carcinogenesis exist. OBJECTIVES: To investigate potential oncogenic effects of expressing recombinant type VII collagen in patient cells. METHODS: We used retroviral transduction to introduce type VII collagen into keratinocytes derived from patients with and without RDEB. RESULTS: Retroviral expression of type VII collagen in cSCC keratinocytes established from patients with RDEB resulted in increased cell adhesion, migration and invasion coupled with a concurrent increase in PI3K and MAPK signalling. CONCLUSIONS: Our data suggest caution when formulating strategies where delivery of type VII collagen is likely to exceed levels seen under normal physiological conditions in a patient group with a higher inherent risk of developing skin cancer.

Genotype-oropharyngeal phenotype correlation in Mexican patients with dystrophic epidermolysis bullosa.

Previous investigations have attempted to correlate the genotype with the cutaneous phenotype in patients with epidermolysis bullosa (EB), but never with the oropharyngeal phenotype. Seventeen dystrophic EB (DEB) patients were genotyped for COL7A1 gene mutations and divided into five distinct groups. Oropharyngeal disease severity was assessed with the Epidermolysis Bullosa Oropharyngeal Severity (EBOS) score by an oral medicine specialist. The genotype-phenotype correlation was calculated by Kruskal-Wallis analysis of variance using the Mann-Whitney test, applying the Bonferroni correction. The most severe oropharyngeal phenotype was found in the group with the 2470insG/3948insT mutation, with a mean disease severity score of 18.50 ± 2.12; the mildest was found in the 6862del16 mutation group, with a mean disease severity score of 0.57 ± 1.13. The most significant difference in median score was found in the total score (P = 0.009), followed by tongue (P = 0.02) and upper lip (P = 0.021), but no correlation was found between disease severity and the groups (P>0.005, after Bonferroni correction). Multiple comparisons among the five different genotypic groups revealed no statistically significant genotype-oropharyngeal phenotype correlation; it was not possible to establish which group was more severe, or to associate a specific mutation to a specific oropharyngeal phenotype.

Lepra: puesta al día. Definición, patogénesis, clasificación, diagnóstico y tratamiento / Leprosy. An Update: Definition, Pathogenesis, Classification, Diagnosis, and Treatmen

La lepra es una enfermedad granulomatosa crónica causada por una micobacteria (M. leprae) que presenta predisposición por la piel y los nervios periféricos. La lepra continúa siendo endémica en distintas regiones del mundo. La presentación clínica de la enfermedad depende del estado inmunológico del paciente al adquirirla y de la evolución de la misma. Es una infección que se asocia a discapacidad y marginación. El diagnóstico de lepra es clínico y se hace al tener uno o más de los signos cardinales establecidos por la OMS: máculas hipopigmentadas o eritematosas con disminución de la sensibilidad, engrosamiento de los nervios periféricos y la demostración de bacilos ácido alcohol resistentes en una baciloscopia o biopsia de piel, con pérdida de anexos en los sitios afectados. El tratamiento consta de tres fármacos: rifampicina, clofazimina y dapsona. Existen principalmente dos modalidades de tratamiento dependiendo de la presentación clínica del paciente: paucibacilar o multibacilar (AU)

Leprosy is a chronic granulomatous disease caused by the bacillus Mycobacterium leprae. It primarily affects the skin and peripheral nerves and is still endemic in various regions of the world. Clinical presentation depends on the patient's immune status at the time of infection and during the course of the disease. Leprosy is associated with disability and marginalization. Diagnosis is clinical and is made when the patient has at least 1 of the following cardinal signs specified by the World Health Organization: hypopigmented or erythematous macules with sensory loss; thickened peripheral nerves; or positive acid-fast skin smear or skin biopsy with loss of adnexa at affected sites. Leprosy is treated with a multidrug combination of rifampicin, clofazimine, and dapsone. Two main regimens are used depending on whether the patient has paucibacillary or multibacillary disease (AU)

Leprosy. An update: definition, pathogenesis, classification, diagnosis, and treatment.

Leprosy is a chronic granulomatous disease caused by the bacillus Mycobacterium leprae. It primarily affects the skin and peripheral nerves and is still endemic in various regions of the world. Clinical presentation depends on the patient's immune status at the time of infection and during the course of the disease. Leprosy is associated with disability and marginalization. Diagnosis is clinical and is made when the patient has at least 1 of the following cardinal signs specified by the World Health Organization: hypopigmented or erythematous macules with sensory loss; thickened peripheral nerves; or positive acid-fast skin smear or skin biopsy with loss of adnexa at affected sites. Leprosy is treated with a multidrug combination of rifampicin, clofazimine, and dapsone. Two main regimens are used depending on whether the patient has paucibacillary or multibacillary disease.

[Immunofluorescence mapping for diagnosis of congenital epidermolysis bullosa]. / Mapeo por inmunofluorescencia para el diagnóstico de epidermólisis ampollosa congénita.

The tools for diagnosis of epidermolysis bullosa have advanced greatly since Hintner's group introduced antigen mapping as a diagnostic test for this family of genodermatoses. Monoclonal or polyclonal antibodies raised against some of the specific proteins found in the epidermis and basement membrane of the epidermis have allowed 4 types of epidermolysis bullosa de be identified and all variants to be classified. When a newborn baby presents with blisters, many conditions are implicated in the differential diagnosis. Examination under an optical microscope can suggest epidermolysis bullosa, but immunofluorescence mapping and electron microscopy are required for confirmation of the diagnosis and further classification of congenital epidermolysis bullosa. This article explains the importance of immunofluorescence antigen mapping and describes the methods employed for classification and subclassification of epidermolysis bullosa.

Mapeo por inmunofluorescencia para el diagnóstico de epidermólisis ampollosa congénita / Immunofluorescence Mapping for Diagnosis of Congenital Epidermolysis Bullosa

Las herramientas para el diagnóstico en las epidermólisis ampollosas (EA) han tenido un gran avance desde que Hintner et al, introdujeron el mapeo antigénico como prueba diagnóstica en este grupo de genodermatosis. La utilización de anticuerpos monoclonales/policlonales dirigidos contra algunas de las proteínas específicas que conforman la epidermis y la membrana basal epidérmica, han servido para clasificar los 4 tipos de epidermólisis ampollosa y subclasificar todas sus variantes. Ante la presencia de un recién nacido con ampollas surgen diagnósticos diferenciales múltiples, en donde la microscopia de luz orienta el diagnostico de epidermólisis ampollosa. Sin embargo, el mapeo por inmunofluorescencia y la microscopia electrónica permiten confirmar y clasificar a las epidermólisis ampollosas congénitas. En este artículo, se explica la importancia y metodología para desarrollar la técnica de mapeo antigénico por inmunofluorescencia, con el propósito de clasificar y subclasificar las epidermólisis ampollosas (AU)

The tools for diagnosis of epidermolysis bullosa have advanced greatly since Hintner's group introduced antigen mapping as a diagnostic test for this family of genodermatoses. Monoclonal or polyclonal antibodies raised against some of the specific proteins found in the epidermis and basement membrane of the epidermis have allowed 4 types of epidermolysis bullosa de be identified and all variants to be classified. When a newborn baby presents with blisters, many conditions are implicated in the differential diagnosis. Examination under an optical microscope can suggest epidermolysis bullosa, but immunofluorescence mapping and electron microscopy are required for confirmation of the diagnosis and further classification of congenital epidermolysis bullosa. This article explains the importance of immunofluorescence antigen mapping and describes the methods employed for classification and subclassification of epidermolysis bullosa (AU)

[Congenital epidermolysis bullosa: a review]. / Epidermólisis ampollosa congénita: revisión del tema.

Epidermolysis bullosa is a group of hereditary diseases affecting 1 in 17,000 live births worldwide. It consists of blistering of the skin and mucous membranes in response to minimal trauma. The disorder seriously affects the patient's quality of life. Diagnosis is based on immunofluorescence mapping and electron microscopy. Treatment is symptomatic, although new cellular and molecular therapies are currently under investigation. This review covers aspects of the molecular biology, clinical presentation, diagnosis, and treatment of epidermolysis bullosa relevant to improving the care for affected patients.

Sabinas syndrome in monozygotic twins.

A pair of 2-year-old female monozygotic twins presented with short and brittle hair. There was marked reduction in hair density, and excessive curving of the eyelashes. Onychodystrophy was also evident. They also had developmental delay in verbal and motor skills. Neither their parents nor other relatives were known to be affected, and there was no history of consanguinity. Examination of the hair shaft under light microscopy showed trichoschisis, which was more evident under electron microscopy. Under polarized light, the hair shafts showed the pathognomonic 'tiger-tail' pattern. The level of sulphur in the hair was low. Both patients were negative for TTDN1 mutation. Clinical correlation was performed and the diagnosis of Sabinas syndrome was made. Sabinas syndrome is a very rare autosomal recessive disorder first described in a group of patients from a small community in north-eastern Mexico. It is diagnosable at birth, and its major symptoms include brittle hair, mental retardation and nail dysplasia. Structural hair abnormalities are seen by both light and electron microscopy.