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1.
Psychol Med ; 54(8): 1810-1823, 2024 Jun.
Article de Anglais | MEDLINE | ID: mdl-38288603

RÉSUMÉ

BACKGROUND: Incidence of first-episode psychosis (FEP) varies substantially across geographic regions. Phenotypes of subclinical psychosis (SP), such as psychotic-like experiences (PLEs) and schizotypy, present several similarities with psychosis. We aimed to examine whether SP measures varied across different sites and whether this variation was comparable with FEP incidence within the same areas. We further examined contribution of environmental and genetic factors to SP. METHODS: We used data from 1497 controls recruited in 16 different sites across 6 countries. Factor scores for several psychopathological dimensions of schizotypy and PLEs were obtained using multidimensional item response theory models. Variation of these scores was assessed using multi-level regression analysis to estimate individual and between-sites variance adjusting for age, sex, education, migrant, employment and relational status, childhood adversity, and cannabis use. In the final model we added local FEP incidence as a second-level variable. Association with genetic liability was examined separately. RESULTS: Schizotypy showed a large between-sites variation with up to 15% of variance attributable to site-level characteristics. Adding local FEP incidence to the model considerably reduced the between-sites unexplained schizotypy variance. PLEs did not show as much variation. Overall, SP was associated with younger age, migrant, unmarried, unemployed and less educated individuals, cannabis use, and childhood adversity. Both phenotypes were associated with genetic liability to schizophrenia. CONCLUSIONS: Schizotypy showed substantial between-sites variation, being more represented in areas where FEP incidence is higher. This supports the hypothesis that shared contextual factors shape the between-sites variation of psychosis across the spectrum.


Sujet(s)
Troubles psychotiques , Trouble de la personnalité schizotypique , Humains , Troubles psychotiques/épidémiologie , Mâle , Femelle , Europe/épidémiologie , Adulte , Brésil/épidémiologie , Jeune adulte , Adolescent , Trouble de la personnalité schizotypique/épidémiologie , Incidence , Adulte d'âge moyen , Phénotype
2.
Schizophr Bull ; 47(6): 1653-1662, 2021 10 21.
Article de Anglais | MEDLINE | ID: mdl-33963865

RÉSUMÉ

Duration of untreated psychosis (DUP) is associated with clinical outcomes in people with a diagnosis of first-episode psychosis (FEP), but factors associated with length of DUP are still poorly understood. Aiming to obtain insights into the possible biological impact on DUP, we report genetic analyses of a large multi-center phenotypically well-defined sample encompassing individuals with a diagnosis of FEP recruited from 6 countries spanning 17 research sites, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. Genetic propensity was measured using polygenic scores for schizophrenia (SZ-PGS), bipolar disorder (BD-PGS), major depressive disorder (MDD-PGS), and intelligence (IQ-PGS), which were calculated based on the results from the most recent genome-wide association meta-analyses. Following imputation for missing data and log transformation of DUP to handle skewedness, the association between DUP and polygenic scores (PGS), adjusting for important confounders, was investigated with multivariable linear regression models. The sample comprised 619 individuals with a diagnosis of FEP disorders with a median age at first contact of 29.0 years (interquartile range [IQR] = 22.0-38.0). The median length of DUP in the sample was 10.1 weeks (IQR = 3.8-30.8). One SD increases in SZ-PGS, BD-PGS, MDD-PGS or IQ-PGS were not significantly associated with the length of DUP. Our results suggest that genetic variation does not contribute to the DUP in patients with a diagnosis of FEP disorders.


Sujet(s)
Trouble bipolaire/génétique , Trouble dépressif majeur/génétique , Étude d'association pangénomique , Intelligence/génétique , Troubles psychotiques/génétique , Schizophrénie/génétique , Adulte , Brésil , Études cas-témoins , Europe , Humains , Troubles psychotiques/thérapie , Facteurs temps
3.
Soc Psychiatry Psychiatr Epidemiol ; 55(5): 645-657, 2020 May.
Article de Anglais | MEDLINE | ID: mdl-31974809

RÉSUMÉ

PURPOSE: The EUropean Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study contains an unparalleled wealth of comprehensive data that allows for testing hypotheses about (1) variations in incidence within and between countries, including by urbanicity and minority ethnic groups; and (2) the role of multiple environmental and genetic risk factors, and their interactions, in the development of psychotic disorders. METHODS: Between 2010 and 2015, we identified 2774 incident cases of psychotic disorders during 12.9 million person-years at risk, across 17 sites in 6 countries (UK, The Netherlands, France, Spain, Italy, and Brazil). Of the 2774 incident cases, 1130 cases were assessed in detail and form the case sample for case-control analyses. Across all sites, 1497 controls were recruited and assessed. We collected data on an extensive range of exposures and outcomes, including demographic, clinical (e.g. premorbid adjustment), social (e.g. childhood and adult adversity, cannabis use, migration, discrimination), cognitive (e.g. IQ, facial affect processing, attributional biases), and biological (DNA via blood sample/cheek swab). We describe the methodology of the study and some descriptive results, including representativeness of the cohort. CONCLUSIONS: This resource constitutes the largest and most extensive incidence and case-control study of psychosis ever conducted.


Sujet(s)
Interaction entre gènes et environnement , Schizophrénie/épidémiologie , Adolescent , Adulte , Brésil/épidémiologie , Études cas-témoins , Ethnies , Europe/épidémiologie , Femelle , Humains , Incidence , Mâle , Adulte d'âge moyen , Jeune adulte
4.
Mem Inst Oswaldo Cruz ; 114: e190056, 2019.
Article de Anglais | MEDLINE | ID: mdl-31389520

RÉSUMÉ

BACKGROUND: Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers. OBJECTIVES: The present study describes the frequency of fibrosis along with its characterisation and pathogenic development. METHODS: Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori's trichrome) and fibrosis was evaluated via semi-quantitative estimation. FINDINGS: Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres. MAIN CONCLUSIONS: The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.


Sujet(s)
Fibrose/anatomopathologie , Lèpre tuberculoïde/anatomopathologie , Nerfs périphériques/anatomopathologie , Biopsie , Humains , Immunohistochimie , Neuropathies périphériques/anatomopathologie , Cellules de Schwann/anatomopathologie
5.
Lancet Psychiatry ; 6(5): 427-436, 2019 May.
Article de Anglais | MEDLINE | ID: mdl-30902669

RÉSUMÉ

BACKGROUND: Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder. METHODS: We included patients aged 18-64 years who presented to psychiatric services in 11 sites across Europe and Brazil with first-episode psychosis and recruited controls representative of the local populations. We applied adjusted logistic regression models to the data to estimate which patterns of cannabis use carried the highest odds for psychotic disorder. Using Europe-wide and national data on the expected concentration of Δ9-tetrahydrocannabinol (THC) in the different types of cannabis available across the sites, we divided the types of cannabis used by participants into two categories: low potency (THC <10%) and high potency (THC ≥10%). Assuming causality, we calculated the population attributable fractions (PAFs) for the patterns of cannabis use associated with the highest odds of psychosis and the correlation between such patterns and the incidence rates for psychotic disorder across the study sites. FINDINGS: Between May 1, 2010, and April 1, 2015, we obtained data from 901 patients with first-episode psychosis across 11 sites and 1237 population controls from those same sites. Daily cannabis use was associated with increased odds of psychotic disorder compared with never users (adjusted odds ratio [OR] 3·2, 95% CI 2·2-4·1), increasing to nearly five-times increased odds for daily use of high-potency types of cannabis (4·8, 2·5-6·3). The PAFs calculated indicated that if high-potency cannabis were no longer available, 12·2% (95% CI 3·0-16·1) of cases of first-episode psychosis could be prevented across the 11 sites, rising to 30·3% (15·2-40·0) in London and 50·3% (27·4-66·0) in Amsterdam. The adjusted incident rates for psychotic disorder were positively correlated with the prevalence in controls across the 11 sites of use of high-potency cannabis (r = 0·7; p=0·0286) and daily use (r = 0·8; p=0·0109). INTERPRETATION: Differences in frequency of daily cannabis use and in use of high-potency cannabis contributed to the striking variation in the incidence of psychotic disorder across the 11 studied sites. Given the increasing availability of high-potency cannabis, this has important implications for public health. FUNDING SOURCE: Medical Research Council, the European Community's Seventh Framework Program grant, São Paulo Research Foundation, National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust and King's College London and the NIHR BRC at University College London, Wellcome Trust.


Sujet(s)
Abus de marijuana/épidémiologie , Troubles psychotiques/épidémiologie , Adulte , Brésil/épidémiologie , Études cas-témoins , Europe/épidémiologie , Femelle , Humains , Incidence , Mâle , Abus de marijuana/complications , Adulte d'âge moyen , Odds ratio , Troubles psychotiques/étiologie , Jeune adulte
6.
SAGE Open Med Case Rep ; 7: 2050313X19828918, 2019.
Article de Anglais | MEDLINE | ID: mdl-30800309

RÉSUMÉ

Mixed adenoneuroendocrine carcinomas are rare tumors that contain both an exocrine and an endocrine component. Since the latest classification by the World Health Organization and with the aid of immunostaining, more mixed adenoneuroendocrine carcinomas are now identified and diagnosed. Nonetheless, our knowledge of these tumors is still limited, notably concerning gastric variants, as the cases reported in the literature are very limited. The clinical and surgical treatment, including the chemotherapy schemes, the prognosis, and recurrence still represent challenges for the medical teams. We present the case of a 62-year-old woman. After an upper endoscopy revealed multiple polyps and a low-grade neuroendocrine tumor, a D2 radical gastrectomy was performed. A low output esophageal anastomotic leak was discovered in the postoperative period and successfully managed. Pathology revealed a gastric mixed adenoneuroendocrine carcinoma, the first case of this kind reported in Ecuador. Patient is doing well and under constant surveillance up until her 13th postoperative month.

7.
Mem. Inst. Oswaldo Cruz ; 114: e190056, 2019. tab, graf
Article de Anglais | LILACS | ID: biblio-1012667

RÉSUMÉ

BACKGROUND Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers. OBJECTIVES The present study describes the frequency of fibrosis along with its characterisation and pathogenic development. METHODS Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori's trichrome) and fibrosis was evaluated via semi-quantitative estimation. FINDINGS Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres. MAIN CONCLUSIONS The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.


Sujet(s)
Humains , Fibrose/diagnostic , Fibrose/thérapie , Lèpre tuberculoïde/diagnostic , Lèpre tuberculoïde/prévention et contrôle
8.
J Surg Case Rep ; 2018(9): rjy246, 2018 Sep.
Article de Anglais | MEDLINE | ID: mdl-30254733

RÉSUMÉ

Wilkie's syndrome is a rare cause of duodenal obstruction that can easily be missed at clinical practice. It is characterized by nausea, abdominal pain and vomit. It usually affects young adults, and it's caused by a low aortomesenteric angle resulting in vascular compression of the duodenum. Symptoms could resemble many of the symptoms presented in a patient with a suspected eating disorder. The non-specificity of the clinical signs and symptoms can confuse, delay the diagnosis and expose the patient to potentially hazardous therapies. We report a case of a 20-year-old patient who presented to the emergency room with a history of intermittent vomiting and abdominal pain. He had been previously misdiagnosed with an eating disorder and received physiological therapy. Nonetheless, his pain persisted. After further evaluation with the use of imaging techniques, a low aortomesenteric angle was discovered. He underwent surgery and completely recovered. On follow up controls patient is well and he no longer had episodes of vomiting.

9.
Mol Cell Biochem ; 447(1-2): 1-7, 2018 Oct.
Article de Anglais | MEDLINE | ID: mdl-29372531

RÉSUMÉ

The human amylin is a pancreatic peptide hormone found in hyperhormonemic state along with insulin in subclinical diabetes. Amylin has been associated with the pathology of type 2 diabetes, particularly due to its ability to assembly into toxic oligomers and amyloid specimens. On the other hand, some variants such as murine amylin has been described as non-amyloidogenic, either in vitro or in vivo. Recent data have demonstrated the amyloid propensity of murine amylin and the therapeutic analogue pramlintide, suggesting a universality for amylin amyloidosis. Here, we report the amyloidogenesis of murine amylin, which showed lower responsivity to the fluorescent probe thioflavin T compared to human amylin, but presented highly organized fibrilar amyloid material. The aggregation of murine amylin also resulted in the formation of cytotoxic specimens, as evaluated in vitro in INS-1 cells. The aggregation product from murine amylin was responsive to a specific antibody raised against amyloid oligomers, the A11 oligomer antibody. Pancreatic islets of wild-type Swiss male mice have also shown responsivity for the anti-oligomer, indicating the natural abundance of such specimen in rodents. These data provide for the first time evidences for the toxic nature of oligomeric assemblies of murine amylin and its existence in wild-type, non-transgenic mice.


Sujet(s)
Amyloïde/immunologie , Anticorps/pharmacologie , Cellules à insuline/immunologie , Polypeptide amyloïde des ilots/immunologie , Polypeptide amyloïde des ilots/toxicité , Agrégation pathologique de protéines/immunologie , Animaux , Anticorps/immunologie , Humains , Cellules à insuline/anatomopathologie , Mâle , Souris , Agrégation pathologique de protéines/anatomopathologie
10.
JAMA Psychiatry ; 75(1): 36-46, 2018 01 01.
Article de Anglais | MEDLINE | ID: mdl-29214289

RÉSUMÉ

Importance: Psychotic disorders contribute significantly to the global disease burden, yet the latest international incidence study of psychotic disorders was conducted in the 1980s. Objectives: To estimate the incidence of psychotic disorders using comparable methods across 17 catchment areas in 6 countries and to examine the variance between catchment areas by putative environmental risk factors. Design, Setting, and Participants: An international multisite incidence study (the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions) was conducted from May 1, 2010, to April 1, 2015, among 2774 individuals from England (2 catchment areas), France (3 catchment areas), Italy (3 catchment areas), the Netherlands (2 catchment areas), Spain (6 catchment areas), and Brazil (1 catchment area) with a first episode of nonorganic psychotic disorders (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes F20-F33) confirmed by the Operational Criteria Checklist. Denominator populations were estimated using official national statistics. Exposures: Age, sex, and racial/ethnic minority status were treated as a priori confounders. Latitude, population density, percentage unemployment, owner-occupied housing, and single-person households were treated as catchment area-level exposures. Main Outcomes and Measures: Incidence of nonorganic psychotic disorders (ICD-10 codes F20-F33), nonaffective psychoses (ICD-10 codes F20-F29), and affective psychoses (ICD-10 codes F30-F33) confirmed by the Operational Criteria Checklist. Results: A total of 2774 patients (1196 women and 1578 men; median age, 30.5 years [interquartile range, 23.0-41.0 years]) with incident cases of psychotic disorders were identified during 12.9 million person-years at risk (crude incidence, 21.4 per 100 000 person-years; 95% CI, 19.4-23.4 per 100 000 person-years). A total of 2183 patients (78.7%) had nonaffective psychotic disorders. After direct standardization for age, sex, and racial/ethnic minority status, an 8-fold variation was seen in the incidence of all psychotic disorders, from 6.0 (95% CI, 3.5-8.6) per 100 000 person-years in Santiago, Spain, to 46.1 (95% CI, 37.3-55.0) per 100 000 person-years in Paris, France. Rates were elevated in racial/ethnic minority groups (incidence rate ratio, 1.6; 95% CI, 1.5-1.7), were highest for men 18 to 24 years of age, and were lower in catchment areas with more owner-occupied homes (incidence rate ratio, 0.8; 95% CI, 0.7-0.8). Similar patterns were observed for nonaffective psychoses; a lower incidence of affective psychoses was associated with higher area-level unemployment (incidence rate ratio, 0.3; 95% CI, 0.2-0.5). Conclusions and Relevance: This study confirmed marked heterogeneity in risk for psychotic disorders by person and place, including higher rates in younger men, racial/ethnic minorities, and areas characterized by a lower percentage of owner-occupied houses.


Sujet(s)
Comparaison interculturelle , Troubles psychotiques/traitement médicamenteux , Troubles psychotiques/épidémiologie , Adulte , Facteurs âges , Brésil , 2435/statistiques et données numériques , Angleterre , Femelle , France , Interaction entre gènes et environnement , Humains , Incidence , Italie , Mâle , Minorités/statistiques et données numériques , Pays-Bas , Troubles psychotiques/génétique , Facteurs de risque , Facteurs sexuels , Espagne
11.
PLoS Negl Trop Dis ; 4(6): e726, 2010 Jun 29.
Article de Anglais | MEDLINE | ID: mdl-20614019

RÉSUMÉ

BACKGROUND: Human paracoccidioidomycosis (PCM) is an endemic fungal disease of pulmonary origin. Follow-up of pulmonary lesions by image studies in an experimental model of PCM has not been previously attempted. This study focuses on defining patterns, topography and intensity of lung lesions in experimentally infected PCM mice by means of a comparative analysis between High Resolution Computed Tomography (HRCT) and histopathologic parameters. METHODOLOGY: Male BALB/c mice were intranasally inoculated with 3 x 10(6) Paracoccidioides brasiliensis (Pb) conidia (n = 50) or PBS (n = 50). HRCT was done every four weeks to determine pulmonary lesions, quantify lung density, reconstruct and quantify lung air structure. Lungs were also analyzed by histopathology and histomorphometry. RESULTS: Three different patterns of lesions were evidenced by hrct and histopathology, as follows: nodular-diffuse, confluent and pseudo-tumoral. The lesions were mainly located around the hilus and affected more frequently the left lung. At the 4th week post-challenge HRCT showed that 80% of the Pb-infected mice had peri-bronchial consolidations associated with a significant increase in upper lung density when compared with controls, (-263+/-25 vs. -422+/-10 HU, p<0.001). After the 8th and 12th weeks, consolidation had progressed involving also the middle regions. Histopathology revealed that consolidation as assessed by HRCT was equivalent histologically to a confluent granulomatous reaction, while nodules corresponded to individual compact granulomas. At the 16th week of infection, confluent granulomas formed pseudotumoral masses that obstructed large bronchi. Discrete focal fibrosis was visible gradually around granulomas, but this finding was only evident by histopathology. CONCLUSIONS/SIGNIFICANCE: This study demonstrated that conventional HRCT is a useful tool for evaluation and quantification of pulmonary damage occurring in experimental mouse PCM. The experimental design used decreases the need to sacrifice a large number of animals, and serves to monitor treatment efficacy by means of a more rational approach to the study of human lung disease.


Sujet(s)
Poumon/imagerie diagnostique , Poumon/anatomopathologie , Blastomycose sud-américaine/imagerie diagnostique , Blastomycose sud-américaine/anatomopathologie , Analyse de variance , Animaux , Modèles animaux de maladie humaine , Histocytochimie , Mâle , Souris , Souris de lignée BALB C , Pneumopathie infectieuse/anatomopathologie , Radiographie thoracique , Tomodensitométrie/méthodes
12.
An. bras. dermatol ; An. bras. dermatol;83(1): 25-31, jan.-fev. 2008. ilus, tab
Article de Portugais | LILACS | ID: lil-478733

RÉSUMÉ

FUNDAMENTOS: As neoplasias malignas da pele de grandes dimensões apresentam dificuldades de reconstrução após a excisão. OBJETIVO: O objetivo deste estudo foi avaliar a exeqüibilidade de uma nova proposta de cobertura para feridas cirúrgicas criadas após a ressecção de grandes tumores cutâneos, a combinação da derme acelular humana com epitélio autólogo cultivado. MÉTODOS: A aplicação dos substitutos de pele foi feita em quatro pacientes com área de implante variando de 33 a 120 cm2. Além da observação dos resultados clínicos, realizou-se estudo morfológico para avaliação da integração dos implantes. RESULTADOS: Ceratinócitos autólogos cultivados foram enxertados em dois pacientes e não demonstraram integração. A derme acelular foi aplicada em quatro pacientes, sendo que em um deles foram feitas duas aplicações. Dos cinco implantes de derme acelular realizados, dois não apresentaram integração, em dois a integração foi de 70 por cento, e de 50 por cento no último. CONCLUSÃO: A cobertura imediata e definitiva de defeitos cirúrgicos através da aplicação de derme acelular humana combinada com epitélio autólogo cultivado é exeqüível. Em oncologia cutânea apenas em situações especiais o uso de substitutos de pele pode ser conveniente no sentido de evitar reconstruções mais complexas.


BACKGROUND: Reconstruction difficulties may arise after excision of large malignant skin neoplasms.a OBJECTIVE: The objective of this study was to assess the feasibility of a new coverage for surgical wounds following resection of large skin tumors: a combination of human acellular dermis with cultured autologous epithelium. METHODS: The skin substitute was implanted in four patients, one of them received two implants and the area ranged from 33 to 120 cm2. Clinical results and morphologic studies were assessed as to implant integration. RESULTS: Cultured autologous epithelium was grafted in two patients and no integration was observed. The acellular dermis was applied to four patients. Out of five acellular dermis implants, two did not present integration, two presented 70 percent integration and the remaining, 50 percent integration. CONCLUSION: The immediate and definite coverage of surgical defects by means of application of human acellular dermis combined with cultured autologous epithelium is feasible. In skin oncology, the use of skin substitutes might be convenient only in special situations to avoid more complex reconstructions.

13.
Acta Dermatovenerol Croat ; 15(2): 65-71, 2007.
Article de Anglais | MEDLINE | ID: mdl-17631783

RÉSUMÉ

Cutaneous aging is a complex biological phenomenon, dependent not only on the innate or intrinsic process ("biological clock"), but also on extrinsic elements, primarily chronic sun exposure (photoaging). In order to verify dermal morphological changes in the elastic fiber system and collagen associated with aged skin, we performed a light and electron microscopic study on exposed-shaved albino mice, which were exposed to UVB radiation. The experimental group consisted of 48 exposed animals, randomly distributed in three groups and submitted to different radiation doses (A, 28800 J/m2; B, 57600 J/m2; and C, 86400 J/m2) and studied 0, 30, 60 and 90 days of exposure discontinuation. Nonexposed-shaved and nonexposed-nonshaved animals were included as controls. From the day of exposure discontinuation and subsequently, the elastic system and collagen network were progressively modified. The increase in collagen fibril diameter was prominent in the 60 and 90 day groups (p<0.05), as noticed on electron microscopy. Elastic fiber density also increased after irradiation (p<0.05). On electron microscopy, elastogenesis was seen in the deep dermis. The comparative study among the groups disclosed clear relationship between doses and "elastotic changes". It also showed that chronological aging of mice skin was apparently intensified after UVB exposure. Skin elastogenesis seems to be a major consequence of UVB exposure, apart from elastolysis, and occurs not only in humans but also in hairless mice submitted to continuous, long-term UVB exposure.


Sujet(s)
Derme/effets des radiations , Collagènes fibrillaires/effets des radiations , Rayons ultraviolets , Animaux , Derme/physiopathologie , Derme/ultrastructure , Élasticité/effets des radiations , Collagènes fibrillaires/physiologie , Collagènes fibrillaires/ultrastructure , Souris , Souris de lignée BALB C , Dose de rayonnement , Vieillissement de la peau/effets des radiations , Facteurs temps
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