Measuring the viscoelastic relaxation function of cells with a time-dependent interpretation of the Hertz-Sneddon indentation model.

The Hertz-Sneddon elastic indentation model is widely adopted in the biomechanical investigation of living cells and other soft materials using atomic force microscopy despite the explicit viscoelastic nature of these materials. In this work, we demonstrate that an exact analytical viscoelastic force model for power-law materials, can be interpreted as a time-dependent Hertz-Sneddon-like model. Characterizing fibroblasts (L929) and osteoblasts (OFCOLII) demonstrates the model's accuracy. Our results show that the difference between Young's modulus EY obtained by fitting force curves with the Hertz-Sneddon model and the effective Young's modulus derived from the viscoelastic force model is less than 3%, even when cells are probed at large forces where nonlinear deformation effects become significant. We also propose a measurement protocol that involves probing samples at different indentation speeds and forces, enabling the construction of the average viscoelastic relaxation function of samples by conveniently fitting the force curves with the Hertz-Sneddon model.

Dermatosis pustular subcórnea: experiencia de once años en un centro de referencia nacional. Reporte de casos / Subcorneal pustular dermatosis: Eleven years of experience in a national reference center

Resumen La dermatosis pustular subcórnea es una dermatosis infrecuente y poco conocida. El objetivo de este trabajo es describir la experiencia de los autores en el diagnóstico y tratamiento de un grupo de pacientes colombianos con esta enfermedad. Se presentan seis casos diagnosticados entre los años 2010 y 2021. Todos los afectados tenían lesiones de larga evolución (en promedio 5 años) y las zonas del cuerpo más afectadas fueron el tórax (83 %), las axilas (66 %) y el tercio proximal de las extremidades (50 %). Las lesiones semiológicas más comunes fueron las pústulas (83 %), las pápulas (83 %) y las placas eritematocostrosas con bordes circinados (50 %); las pústulas flácidas típicas solo se observaron en dos casos (33 %). En conclusión, el diagnóstico de la dermatosis pustular subcórnea requiere del reconocimiento de un amplio espectro de manifestaciones clínicas, así como una adecuada correlación clínico-patológica.

Abstract Subcorneal pustular dermatosis is a rare and little known dermatosis. The objective of this paper is to describe the experience of the authors in the diagnosis and treatment of a group of Colombian patients with this disease. Six cases are presented, diagnosed between 2010 and 2021. All of the patients had long-standing lesions (on average 5 years) and the most affected areas were the thorax (83%), the armpits (66%), and the proximal third of the extremities (50%). The most common lesions were pustules (83%), papules (83%), and erythematous-crusted plaques with circinated edges (50%); typical flaccid pustules were only observed in two cases (33%). In conclusion, the timely diagnosis of subcorneal pustular dermatosis requires recognition of a wide spectrum of clinical presentations, as well as adequate clinicopathological correlation.

Pustulosis subcórnea: a propósito de un caso / Subcorneal pustulosis: a case report

Resumen La dermatosis pustulosa subcórnea (DPS), oenfermedad de Sneddon-Wilkinson, es una dermatosis poco frecuente, benigna, de curso crónico y recidivante. En esta oportunidad presentaremos el caso de una paciente femenina de 58 años condiagnóstico de dermatosis pustulosa subcórnea, que fue tratada con dapsona 100mg por día, con resolución de lesiones. Realizamos unarevisión bibliográfica de esta patología describiendo sus características clínicas e histológicas, sus múltiples diagnósticos diferenciales y las posibles terapéuticas.

Abstract Subcorneal pustular dermatosis, or Sneddon-Wilkinson disease, is a rare, benign, chronic and recurrent dermatosis. We reportthe case of a 58-year-old female patient with subcorneal pustular dermatosis, who was treated with dapsone 100mg per day, with goodtherapeutic response. We carried out a bibliographic review of this pathology describing its clinical and histological characteristics, its multiple differential diagnoses and possible therapeutic options.

Dermatosis Pustulosa Subcórnea / Subcorneal pustular dermatosis

RESUMEN La dermatosis pustulosa subcórnea o enfermedad de Sneddon Wilkinson, es una enfermedad poco frecuente, caracterizada por lesiones pustulosas, recurrentes que suelen coalescer. Esta afección también se relaciona con enfermedades neoplásicas o inmunológicas. El propósito de este estudio es describir un caso clínico de ladermatosis referida en una paciente de 54 años de edad inicialmente tratada con dapsona, aunque,si bien, durante dos meses hubo mejoría, posteriormente se observa desarrollo de nuevas lesiones y alteración de las transaminasas. Por este motivo se procede a cambiar de tratamiento, por trimetoprima /sulfametoxazol.

Abstract Subcorneal pustular dermatosis or Sneddon Wilkinson's disease is a rare disease characterized by recurrent pustular lesions that often coalesce. This condition is also associated with neoplastic or immunologic diseases. The purpose of this study is to describe a clinical case of the referred dermatosis in a 54-year-old female patient initially treated with dapsone, although there was improvement for two months, subsequently new lesions developed and transaminase alteration was observed, for this reason the treatment was changed to trimethoprim/sulfamethoxazole.

Primary Antiphospholipid Syndrome with Livedo Reticularis is Linked to Female Sex and Stroke and Negatively Associated with Thyroid Disease.

AIMS: To study the clinical and laboratory findings between patients with primary Antiphospholipid Syndrome (pAPS) with and without LR. BACKGROUND: Livedo Reticularis (LR) is a common manifestation of Antiphospholipid Syndrome (APS). Although no previous study evaluated patients with and without LR. METHODS: A transversal study including 66 pAPS patients was performed. Demographical, anthropometric, medication use, antiphospholipid antibodies profile data were evaluated, and LR's clinical and laboratory features. Patients were subdivided into one of two groups: pAPS with LR and pAPS without LR. RESULTS: Both groups were alike concerning demographics and anthropometrics. Interestingly, the frequency of stroke (28.5 vs. 7.5%, p=0.04), as well as of Sneddon's syndrome (100 vs. 30.0%, p<0.0001), were higher in pAPS with LR than the other group. Conversely, patients in the pAPS without LR group had more thyroidopathy than those in the pAPS with LR group (80% vs. 50% %, p=0.03). CONCLUSION: Patients with pAPS and LR have more stroke and seem to be protected from thyroidopathy. Careful follow-up of these patients is therefore advised.

Livedo Racemosa: Clinical, Laboratory, and Histopathological Findings in 33 Patients.

Livedo racemosa is a cutaneous finding characterized by a persistent, erythematous, or violaceous discoloration of the skin, in a broken, branched, discontinuous, and irregular pattern. A retrospective review of 33 cases with clinical diagnosis of livedo racemosa over the past 6 years was evaluated in the dermatology department of a tertiary care hospital. We found predominance in Caucasian women (78.8%); age ranged from 8 to 81 years, with a mean age of 36 years. Livedo racemosa was described as generalized in 12 patients (36.4%), although the main localization was on lower limbs (42%). After laboratory testing and histopathological examinations, 12 patients (36.4%) were classified with idiopathic livedo racemosa; secondary diseases were diagnosis in 21 patients (63.6%), including Sneddon's syndrome, cutaneous polyarteritis nodosa, systemic lupus erythematosus, and others. Medical history of thrombotic events was described in 8 (24.2%) patients, and also 8 (24.2%) patients had abnormal results for 2 or more thrombophilia laboratory tests. Skin biopsy showed no histological abnormalities in 11 cases (33.3%), thrombosis of dermal blood vessels in 10 (30.3%), intimal/subintimal thickening in 7 (21.2%), and vasculitis in 5 (15.2%). In conclusion, livedo racemosa is a clinical feature that might be correlated to vascular disorders, such as thrombotic and/or hypercoagulable states, autoimmune diseases, and neoplastic diseases, or it can be secondary to specific medications. It is essential to establish a correct approach in cases of livedo racemosa, which includes anamnesis, physical examination, laboratory test, histological examination, and complementary examination according to clinical findings, in order to diagnosis underlying causes.

Relato de Caso: Síndrome de Sneddon por Anticorposantifosfolipides / Sneddon's Syndrome by Antiphospholipid Antibodies: Case Report

Introdução: A Síndrome de Sneddon, descrita em 1965, caracteriza-se pela associação de eventos isquêmicos cerebrovasculares com livedo reticular. É rara e tem predomínio em mulheres jovens. Seus sintomas variam de ataques isquêmicos transitórios a acidentes vasculares cerebrais isquêmicos, causado pela obliteração de artérias de pequeno a médio porte, levando a alterações patológicas como a inflamação endotelial, posterior proliferação subintimal e então fibrose. A evolução é lenta e progressiva, podendo levar ao óbito ou incapacidade. Objetivos: descrever o caso de uma paciente com Síndrome de Sneddon que acompanha no Hospital Universitário Evangélico Mackenzie e revisar a literatura atual. Descrição do Caso: mulher, 37 anos conta história de quatro episódios de AVE isquêmico e um de AVE hemorrágico, tendo o primeiro sido aos 22 anos e resultando em afasia, convulsões e hemiparesia a D. Na investigação detectou-se hipertensão arterial, livedo reticularis, nódulos subcutâneos e anticardiolipinas positivas em altos títulos (acima de 100 U/mL), além de plaquetopenia (n=70.000/mm3). Uma ecocardiografia mostrou insuficiência mitral com vegetações em válvulas. A paciente tinha, também, alteração da função renal e uma biópsia mostrou lesão intersticial não imune. Com diagnóstico de síndrome de Sneddon secundária à sindrome do anticorpo antifosfolipide, (SAF) a paciente foi anticoagulada com cumarinicos e sua hipertensão foi controlada com losartana. A investigação para lúpus eritematoso sistêmico subjacente foi negativa Conclusão: SAF é uma das causas da Síndrome de Sneddon e deve ser lembrada toda vez que uma paciente jovem se apresentar com AVEs isquêmicos.

Background: Sneddon's syndrome, described in 1965, is characterized by the association of cerebrovascular ischemic events with livedo reticularis. It is rare and predominates in young women. Its symptoms range from transient ischemic attacks to ischemic strokes, caused by the obliteration of small to medium-sized arteries, leading to pathological changes such as endothelial inflammation, subsequent subintimal proliferation and then fibrosis. The evolution is slow and progressive, leading to death or disability. Aim: Describe the case of a patient with Sneddon Syndrome who is being followed up at Hospital Universitário Evangélico Mackenzie and review the current literature. Case description: A 37-year-old woman tells the story of four episodes of ischemic stroke and one of hemorrhagic stroke, the first being at 22 years of age and resulting in aphasia, seizures and hemiparesis to D. In the investigation, arterial hypertension, livedo reticularis, subcutaneous nodules and positive anticardiolipins in high titers (above 100 U / mL), in addition to thrombocytopenia (n = 70,000 / mm3). An echocardiography showed mitral insufficiency with valve vegetations. The patient also had impaired renal function and a biopsy showed a non-immune interstitial lesion. With a diagnosis of Sneddon's syndrome secondary to the antiphospholipid antibody syndrome (APS), the patient was anticoagulated with cumadinicos and her hypertension was controlled with losartan. The investigation for underlying systemic lupus erythematosus was negative. Conclusion: APS is one of the causes of Sneddon Syndrome and must be remembered whenever a young patient presents with ischemic strokes.

Cognitive and psychiatric changes as first clinical presentation in Sneddon syndrome.

Sneddon syndrome (SS) is a rare progressive non-inflammatory thrombotic vasculopathy affecting small/medium-sized blood vessels of unknown origin. It is strongly associated with the presence of antiphospholipid antibodies (AA). The presence of livedo reticularis and cerebrovascular disease are hallmark features. The condition is far more common in young women. We report a case of SS in a 43 year-old male with a two-year history of progressive cognitive impairment consistent with dementia syndrome, and major personality changes, besides livedo reticularis and cerebral angiographic pattern of vasculitis. AA were borderline. The recognition of skin blemishes that precede strokes should raise the hypothesis of SS. AA are elevated in more than half of cases, but their role in the pathogenesis or association of positive antibodies and SS remains unclear. Dementia syndrome in young patients should be extensively investigated to rule out reversible situations. Typical skin findings, MRI and angiography may aid diagnosis.

A síndrome de Sneddon (SS) é uma vasculopatia trombótica não inflamatória progressiva rara que afeta os vasos sanguíneos de pequeno e médio tamanho com origem desconhecida. Está fortemente associada à presença de anticorpos antifosfolipídios (AA). A presença de livedo reticularis e doença cerebrovascular são a marca registrada. É muito mais comum em mulheres jovens. Relatamos um caso de SS em um homem de 43 anos de idade com dois anos de história de comprometimento cognitivo progressivo compatível com síndrome demencial e mudanças graves de personalidade, além de livedo reticular e padrão angiográfico cerebral de vasculite. AA eram limítrofes. O reconhecimento das manchas da pele que precedem eventos isquêmicos cerebrovasculares deve reforçar a hipótese de SS. Os AA são elevados em mais da metade dos casos, mas seu papel na patogênese ou associação de anticorpos positivos e SS permanece obscuro. A síndrome demencial em pacientes jovens deve ser amplamente investigada para se descartarem situações reversíveis. Achados típicos da pele, ressonância magnética e angiografia podem ajudar no diagnóstico.

Cognitive and psychiatric changes as first clinical presentation in Sneddon Syndrome / Alterações cognitivas e psiquiátricas como primeira apresentação clínica na Síndrome de Sneddon

ABSTRACT Sneddon syndrome (SS) is a rare progressive non-inflammatory thrombotic vasculopathy affecting small/medium-sized blood vessels of unknown origin. It is strongly associated with the presence of antiphospholipid antibodies (AA). The presence of livedo reticularis and cerebrovascular disease are hallmark features. The condition is far more common in young women. We report a case of SS in a 43 year-old male with a two-year history of progressive cognitive impairment consistent with dementia syndrome, and major personality changes, besides livedo reticularis and cerebral angiographic pattern of vasculitis. AA were borderline. The recognition of skin blemishes that precede strokes should raise the hypothesis of SS. AA are elevated in more than half of cases, but their role in the pathogenesis or association of positive antibodies and SS remains unclear. Dementia syndrome in young patients should be extensively investigated to rule out reversible situations. Typical skin findings, MRI and angiography may aid diagnosis.

RESUMO A síndrome de Sneddon (SS) é uma vasculopatia trombótica não inflamatória progressiva rara que afeta os vasos sanguíneos de pequeno e médio tamanho com origem desconhecida. Está fortemente associada à presença de anticorpos antifosfolipídios (AA). A presença de livedo reticularis e doença cerebrovascular são a marca registrada. É muito mais comum em mulheres jovens. Relatamos um caso de SS em um homem de 43 anos de idade com dois anos de história de comprometimento cognitivo progressivo compatível com síndrome demencial e mudanças graves de personalidade, além de livedo reticular e padrão angiográfico cerebral de vasculite. AA eram limítrofes. O reconhecimento das manchas da pele que precedem eventos isquêmicos cerebrovasculares deve reforçar a hipótese de SS. Os AA são elevados em mais da metade dos casos, mas seu papel na patogênese ou associação de anticorpos positivos e SS permanece obscuro. A síndrome demencial em pacientes jovens deve ser amplamente investigada para se descartarem situações reversíveis. Achados típicos da pele, ressonância magnética e angiografia podem ajudar no diagnóstico.

Síndrome de Sneddon asociado a síndrome antifosfolipídico: descripciones clínicas y revisión de la literatura / Sneddon syndrome associated with antiphospholipid syndrome: clinical descriptions and a literature review

Resumen El síndrome de Sneddon es una rara vasculopatía no inflamatoria, obliterante, caracterizada por la asociación de eventos cardiovasculares (hipertensión arterial, claudicación intermitente y enfermedad coronaria), neurológicas (accidentes cerebrovasculares isquémicos, cefalea, vértigo y convulsiones) y livedo reticularis de tipo racemosa. Presentamos a una mujer que ingresa con un cuadro neurológico isquémico, hipertensión arterial, problemas vasculares y lesiones en piel. La biopsia de piel se catalogó como dermatitis perivascular superficial linfocitaria, sugestivo de lesión oclusiva.

Abstract Sneddon syndrome is a rare non-inflammatory obliterative vasculopathy, characterised by the association of cardiovascular (arterial hypertension, intermittent claudication, and coronary artery disease) and neurological events (ischaemic stroke, headache, dizziness and convulsions), and livedo reticularis/livedo racemosa. The case is presented of a woman admitted with an ischaemic neurological disease, hypertension, vascular problems, and skin lesions. The skin biopsy was classified as surface perivascular lymphocytic dermatitis, suggestive of occlusive lesion.

Dermatosis pustulosa subcórnea como debut de un paciente con lupus eritematoso sistémico

El lupus eritematoso sistémico es una enfermedad inflamatoria que afecta fundamentalmente a mujeres en edad fértil, aunque en ocasiones su debut llega en edades tempranas de la vida. Múltiples son las manifestaciones clínicas que pueden aparecer en el curso de la enfermedad y que afectan a todos los órganos y sistemas de órganos del cuerpo humano. Se describen diversas formas de debut de la enfermedad, dentro de las cuales los síntomas generales, afectación neurológica, dermatológica y renal han sido reportada como las más frecuentes. Se presenta el caso de un niño de 6 años de edad que debuta con un lupus eritematoso sistémico y que su lesión o signo de debut es una manifestación dermatológica: la dermatosis pustulosa subcornea

Systemic lupus erythematosus is an inflammatory disease that mainly affects women of childbearing age, although sometimes its debut comes at early ages of life. Multiple are the clinical manifestations that can appear in the course of the disease and that affect all organs and organ systems of the human body. Various forms of disease debut are described, within which the general symptoms, neurological, dermatological and renal involvement have been reported as the most frequent. We present the case of a 6-year-old boy who debuted with systemic lupus erythematosus and whose lesion or debut sign is a dermatological manifestation: the subcorneal pustular dermatosis

Enfermedad de Sneddon-Wilkinson / Sneddon-Wilkinson disease

Introducción: la dermatosis pustulosa subcórnea o enfermedad de Sneddon-Wilkinson, es una enfermedad poco común, que se distingue por pústulas flácidas, recurrentes y coalescentes; su mecanismo etiológico no está del todo dilucidado, pero se relaciona con la presencia de enfermedades neoplásicas o inmunológicas. Presentación del caso: se presenta el caso de un niño de 4 años de edad, que acude a consulta de Dermatología del Hospital Andino de Chimborazo, con manifestaciones clínicas que permiten hacer el diagnóstico de dermatosis pustulosa subcórnea. Conclusiones: la enfermedad de Sneddon-Wilkinson es una afección rara que se presenta frecuentemente en pacientes femeninas de 40 años y más. Se caracteriza por una amplia diversidad de manifestaciones cutáneas que dificultan el pronóstico y la evolución del paciente. Esta enfermedad, cuando se presenta en niños, puede confundirse con otras afecciones que cursan con exantemas cutáneos(AU)

Introduction: subcorneal pustular dermatosis or Sneddon-Wilkinson disease is a rare illness characterized by recurrent, coalescent and flaccid pustules; its etiological mechanism is not totally known, but it is related to neoplastic or immunological diseases. Case presentation: a four-year old child who went to the dermatology service of Hospital Andino de Chimborazo. He presented with clinical manifestations that allow making the diagnosis of subcorneal pustular dermatosis. Conclusions: Sneddon-Wilkinson disease is a rare illness that frequently occurs in 40 years-old and older women. It has a wide range of skin manifestations that makes prognosis and recovery of patient difficult. When it appears in children, it may create confusion with other illnesses having skin exanthemas(AU)

Síndrome de Sneddon: reporte de un caso / Sneddon syndrome: case report

El síndrome de Sneddon es una vasculitis sistémica, que se caracteriza por accidente cerebrovascular isquémico y livedo reticularis. Es una enfermedad rara, que se da principalmente en mujeres jóvenes. Presentamos el caso de una mujer de 20 años con el diagnóstico de Síndrome de Sneddon, tratada en forma oportuna y con una evolución favorable en el hospital Doctor Hernán Henríquez Aravena de Temuco (HHHA).

Sneddon's syndrome is a systemic vasculitis, characterized by ischemic stroke and livedo reticularis. It is a rare disease that occurs mainly in young women. We report the case of a 20 year old woman diagnosed with Sneddon syndrome, treated in time and with a favorable outcome at Dr. Hernán Henríquez Aravena Hospital (HHHA) of Temuco

Sneddon's syndrome: case report and review of its relationship with antiphospholipid syndrome / Síndrome de Sneddon: relato de caso e revisão sobre a relação com a síndrome do anticorpo antifosfolipídio

The Sneddon's syndrome is a rare disorder characterized by the occurrence of cerebrovascular disease associated with livedo reticularis. The antiphospholipid syndrome is the most frequent type of acquired thrombophilia, defined by the occurrence of thrombosis or pregnancy morbidity in the presence of persistently positive antiphospholipid antibodies. Approximately 80% of Sneddon's syndrome patients have an antiphospholipid antibody marker. These antibodies may play a pathogenetic role in some cases of Sneddon's syndrome, and many authors consider these two syndromes as the same entity. Although clinical features of antiphospholipid syndrome and Sneddon's syndrome may overlap, there is a distinction between clinical and laboratory evidence suggesting that these two entities are different diseases. A recent finding of coagulopathies, including elevated levels of coagulation factor VII, decreased levels of protein S, and activated protein C in Sneddon's syndrome patients suggested a possible biological link between the vasculopathy and a primary coagulopathy. Moreover, the clinical course seems to be progressive in Sneddon's syndrome patients and includes increase of disability and cognitive deterioration, more arterial involvement, and the antiphospholipid syndrome shows a more benign course. Both syndromes share clinical and laboratory features, and whether Sneddon's syndrome represents a spectrum of antiphospholipid syndrome remains unclear. Sneddon's syndrome patients have a worse prognosis and may represent a subgroup of patients who demands more rigorous follow-up. It is important to recognize the Sneddon's syndrome, particularly because stroke episodes may be prevented through appropriate treatment.

A síndrome de Sneddon é um distúrbio raro caracterizado pela ocorrência de doença cerebrovascular associada a livedo reticular. A síndrome do anticorpo antifosfolipídio é o tipo mais frequente de trombofilia, definida pela ocorrência de trombose ou morbidade gestacional na presença de anticorpos antifosfolípides persistentemente positivos. Aproximadamente 80% dos pacientes com síndrome de Sneddon apresentam um marcador de anticorpo antifosfolipídio. Esses anticorpos podem exercer um papel fisiopatológico em alguns casos de síndrome de Sneddon, e muitos autores consideram essa síndrome e a síndrome do anticorpo antifosfolipídio a mesma entidade. Apesar de os quadros clínicos das suas síndromes poderem se sobrepor, há evidência clínica e laboratorial distintiva, sugerindo que as duas entidades são doenças diferentes. Um achado recente de coagulopatia, incluindo níveis elevados do fator VII de coagulação, diminuição dos níveis da proteína S, e proteína C ativada em pacientes com síndrome de Sneddon, sugeriu uma possível ligação biológica entre a vasculopatia e coagulopatia primária. Além disso, o curso clínico pareceu ser progressivo em pacientes com síndrome de Sneddon, visto que há aumento de incapacidade e deterioração cognitiva, além de maior envolvimento arterial, enquanto a síndrome do anticorpo antifosfolipídio apresenta um curso mais benigno. Ambas as síndromes compartilham características clínicas e laboratoriais; até qual ponto a síndrome de Sneddon representa um espectro da síndrome do anticorpo antifosfolipídio permanece desconhecido. Os pacientes com a primeira síndrome apresentam pior prognóstico e podem representar um subgrupo de pacientes que requer um seguimento mais rigoroso. É importante reconhecer a síndrome de Sneddon já que os episódios de acidente vascular cerebral podem ser prevenidos com a terapia apropriada.