77 research outputs found

    Melanocortin 1 Receptor Variants in an Irish Population

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    The identification of an association between variants in the human melanocortin 1 receptor (MC1R) gene and red hair and fair skin, as well as the relation between variants of this gene and coat color in animals, suggests that the MC1R is an integral control point in the normal pigmentation phenotype. In order to further define the contribution of MC1R variants to pigmentation in a normal population, we have looked for alterations in this gene in series of individuals from a general Irish population, in whom there is a preponderance of individuals with fair skin type. Seventy-five per cent contained a variant in the MC1R gene, with 30% containing two variants. The Arg151Cys, Arg160Trp, and Asp294His variants were significantly associated with red hair (p = 0.0015, p < 0.001, and p < 0.005, respectively). Importantly, no individuals harboring two of these three variants did not have red hair, although some red-haired individuals only showed one alteration. The same three variants were also over-represented in individuals with light skin type as assessed using a modified Fitzpatrick scale. Despite these associations many subjects with dark hair/darker skin type harbored MC1R variants, but there was no evidence of any particular association of variants with the darker phenotype. The Asp294His variant was similarly associated with red hair in a Dutch population, but was infrequent in red-headed subjects from Sweden. The Asp294His variant was also significantly associated with nonmelanoma skin cancer in a U.K. population. The results show that the Arg151Cys, Arg160Trp, and Asp294His variants are of key significance in determining the pigmentary phenotype and response to ultraviolet radiation, and suggest that in many cases the red-haired component and in some cases fair skin type are inherited as a Mendelian recessive

    Reorganization of the nuclear lamina and cytoskeleton in adipogenesis

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    A thorough understanding of fat cell biology is necessary to counter the epidemic of obesity. Although molecular pathways governing adipogenesis are well delineated, the structure of the nuclear lamina and nuclear-cytoskeleton junction in this process are not. The identification of the ‘linker of nucleus and cytoskeleton’ (LINC) complex made us consider a role for the nuclear lamina in adipose conversion. We herein focused on the structure of the nuclear lamina and its coupling to the vimentin network, which forms a cage-like structure surrounding individual lipid droplets in mature adipocytes. Analysis of a mouse and human model system for fat cell differentiation showed fragmentation of the nuclear lamina and subsequent loss of lamins A, C, B1 and emerin at the nuclear rim, which coincides with reorganization of the nesprin-3/plectin/vimentin complex into a network lining lipid droplets. Upon 18 days of fat cell differentiation, the fraction of adipocytes expressing lamins A, C and B1 at the nuclear rim increased, though overall lamin A/C protein levels were low. Lamin B2 remained at the nuclear rim throughout fat cell differentiation. Light and electron microscopy of a subcutaneous adipose tissue specimen showed striking indentations of the nucleus by lipid droplets, suggestive for an increased plasticity of the nucleus due to profound reorganization of the cellular infrastructure. This dynamic reorganization of the nuclear lamina in adipogenesis is an important finding that may open up new venues for research in and treatment of obesity and nuclear lamina-associated lipodystrophy

    Deficient Plakophilin-1 Expression Due to a Mutation in PKP1 Causes Ectodermal Dysplasia-Skin Fragility Syndrome in Chesapeake Bay Retriever Dogs

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    In humans, congenital and hereditary skin diseases associated with epidermal cell-cell separation (acantholysis) are very rare, and spontaneous animal models of these diseases are exceptional. Our objectives are to report a novel congenital acantholytic dermatosis that developed in Chesapeake Bay retriever dogs. Nine affected puppies in four different litters were born to eight closely related clinically normal dogs. The disease transmission was consistent with an autosomal recessive mode of inheritance. Clinical signs occurred immediately after birth with superficial epidermal layers sloughing upon pressure. At three month of age, dogs exhibited recurrent superficial skin sloughing and erosions at areas of friction and mucocutaneous junctions; their coat was also finer than normal and there were patches of partial hair loss. At birth, histopathology revealed severe suprabasal acantholysis, which became less severe with ageing. Electron microscopy demonstrated a reduced number of partially formed desmosomes with detached and aggregated keratin intermediate filaments. Immunostaining for desmosomal adhesion molecules revealed a complete lack of staining for plakophilin-1 and anomalies in the distribution of desmoplakin and keratins 10 and 14. Sequencing revealed a homozygous splice donor site mutation within the first intron of PKP1 resulting in a premature stop codon, thereby explaining the inability to detect plakophilin-1 in the skin. Altogether, the clinical and pathological findings, along with the PKP1 mutation, were consistent with the diagnosis of ectodermal dysplasia-skin fragility syndrome with plakophilin-1 deficiency. This is the first occurrence of ectodermal dysplasia-skin fragility syndrome in an animal species. Controlled mating of carrier dogs would yield puppies that could, in theory, be tested for gene therapy of this rare but severe skin disease of children

    Over de grens: Nederlands extreem geweld in de Indonesische onafhankelijkheidsoorlog, 1945-1949

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    Op 17 augustus 1945, twee dagen na de Japanse capitulatie, verklaarde Indonesië zich onafhankelijk. Nederland erkende dit niet en trachtte met geweld zelf de regie te voeren over het onvermijdelijke proces van dekolonisatie. Dit leidde tot vier jaren van moeizame onderhandelingen en bittere oorlogvoering. In 2005 verklaarde de Nederlandse regering dat Nederland die oorlog niet had moeten voeren. Over het geweld dat de Nederlandse militairen tijdens deze oorlog hadden toegepast, staat echter nog altijd het regeringsstandpunt uit 1969 overeind: er waren wel ‘excessen’, maar de krijgsmacht had zich in de regel ‘correct’ gedragen.Naarmate de aanwijzingen van extreem Nederlands geweld zich opstapelden, bleek dit officiële standpunt steeds moeilijker vol te houden. De Nederlandse regering besloot daarom in 2016 tot financiering van een groot onderzoeksprogramma. De belangrijkste conclusies daarvan zijn in dit boek te vinden. De auteurs maken aannemelijk dat de Nederlandse krijgsmacht op structurele basis extreem geweld toepaste en dat dit toen en ook lang daarna op allerlei manieren werd toegedekt. Dit alles past slecht bij een rooskleurig nationaal zelfbeeld – zoals eigenlijk de hele koloniale geschiedenis met dat zelfbeeld schuurt.Colonial and Global Histor

    Cancer Biomarker Discovery: The Entropic Hallmark

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    Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

    Cancer-related secondary lymphoedema due to cutaneous lymphangitis carcinomatosa: clinical presentations and review of literature

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    Lymphoedema is a clinical condition caused by impairment of the lymphatic system, leading to swelling of subcutaneous soft tissues. As a result, accumulation of protein-rich interstitial fluid and lymphostasis often causes additional swelling, fibrosis and adipose tissue hypertrophy leading to progressive morbidity and loss of quality of life for the patient. Lymphoedema can be distinguished as primary or secondary. Lymphoedema is a complication frequently encountered in patients treated for cancer, especially after lymphadenoectomy and/or radiotherapy based on destruction of lymphatics. However, although lymphatic impairment is sometimes caused by obstructive solid metastasis, we present three cases of secondary lymphoedema with minor dermatological features without detectable solid metastasis. Sometimes this type of lymphoedema is mistakenly called malignant lymphoedema. All patients were previously treated for cancer without clinical signs of recurrence, presented with progressive lymphoedema and minor dermatological features of unknown origin. Clinical and histopathological examination of the skin revealed diffuse lymphangitis carcinomatosa, leading to secondary lymphoedema and adjustment of the therapeutic approach and prognosis. We reviewed literature on these rare presentations of cancer recurrence and recommend, where appropriate, consulting a dermatologist when discrete skin abnormalities are seen in patients with a history of cancer and developing lymphoedema
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