State of the art in chromovitrectomy / Estado da arte da cromovitrectomia

Vitrectomy is a surgery that involves complex and delicate techniques that treat diseases such as macular hole, epiretinal membrane and diabetic macular edema. Chromovitrectomy is one of these techniques and includes the use of coloring agents such as vital dyes or crystals to enhanced visibility of transparent structures during vitrectomy. The aim of this study was to present a modern approach, based on scientific evidence, about the application and indication of vital coloring agents during vitrectomy. The use of such agents has made this surgery more predictable and has increased its post-operative prognosis. Although research on chromovitrectomy is currently expanding there is still not an established gold standard dyeing agent.

A cirurgia vitreorretiniana é uma cirurgia que envolve técnicas complexas e delicadas que tratam doenças como buraco macular, membrana epirretiniana e o edema macular diabético. A cromovitrectomia é uma dessas técnicas que incluem o uso de corantes compostos de pigmentos vitais ou cristais para melhorar a visibilização de estruturas transparentes durante a cirurgia de vitrectomia. O objetivo desse artigo foi apresentar uma abordagem atual, baseada em evidências, sobre a aplicação e indicação de corantes vitais durante a cirurgia vitreorretiniana. O emprego desses corantes possibilitou uma maior previsibilidade para a cirurgia, melhorando assim seu prognóstico pós-operatório. Apesar do campo da cromovitrectomia está em plena expansão de pesquisas, um corante gold standard para cromovitrectomia ainda não está estabelecido.

Immunohistochemical and light and electron microscopic study of the basement membrane in photoaged skin

The basement membrane plays an important role in maintaining a healthy epidermis and dermis, and repeated damage destabilizes the skin and accelerates the aging process. This study was carried out to detect the changes in human skin basement membrane in sun-exposed skin compared with sun-protected skin. Skin biopsies were taken from sun-exposed and sun-protected skin of 10 male individuals aged between 50 and 60 years and processed for light and electron microscopic examination of the changes of the basement membrane. Immunohistochemical assessment of laminin and matrix metalloproteinase-1 [MMP-1] expression in skin biopsies was also carried out. Histological examination of sections of sun-exposed skin revealed that the basement membrane was discontinuous and the collagenous fibers of the underlying connective tissue were discrete in comparison with sun-protected skin. Immunoreactivity for laminin was decreased, whereas that for MMP-1 was markedly increased in sun-exposed skin as compared with sun-protected skin. The results of the current study revealed that the structure of the basement membrane was affected in sun-exposed skin as regards thickness, continuity, and structure. Increased activity of MMP-1 accounts at least in part for the disruption of the basal lamina and degradation of collagenous fibers of the dermis

Lipoid proteinosis in two Indian brothers - a case report from South Bengal

Lipoid proteinosis is a rare autosomal recessive disorder with variable phenotype, caused by defect in extracellular matrix protein-1 and is characterized by deposition of periodic acid-Schiff-positive, diastase resistant material in skin, mucous membrane and internal organs. There are only few reports regarding lipoid proteinosis in literature and in this part of the world. Here, we report a case of lipoid proteinosis in a 29-year-old male with positive family history and widespread distribution involving skin and internal organs. Histopathological finding was consistent with clinical diagnosis of lipoid proteinosis

role of type IV collagen in developing lens in mouse fetuses

Extracellular matrix [ECM] and basement membrane [BM] play important roles in many developmental processes during development and after birth. Among the components of the BM, collagen fibers specially type IV are the most important parts. The aim of this study was to determine the time when collagen type IV appears in the BM of lens structure during mouse embryonic development. In this experimental study, 22 female Balb/C mice were randomly selected and were kept under normal condition, finding vaginal plug was assumed as day zero of pregnancy. From embryonic day 10 to 20, all specimens were sacrificed by cervical dislocation and their heads were fixed, serially sectioned and immunohistochemistry study for tracing collagen type IV in lens were carried out. Our data revealed that collagen type IV appeared at the early stage of gestation day 12 in BM of anterior epithelial lens cells and the amount of this protein gradually increased until days 15-17 in ECM and posterior capsule epithelium. After this period, severe reaction was not observed in any part of the lens. These findings establish the important role of collagen IV in developing optic cup and any changes during critical period of pregnancy may be result in severe visual system defect

Union dermoepidermica: una barrera selectiva, compleja y vital / Dermoepidermic junction: a selective, complex and vital barrier

La Unión Dermoepidérmica, (UDE) es una región altamente compleja, la cual contiene una gran variedad de elementos celulares, los cuales a pesar de tener un origen embriológico distinto, interaccionan entre sí, generando diferentes sustancias, las cuales mantienen la funcionalidad y homeostasis del órgano más extenso del organismo. La UDE es considerada una lámina basal, altamente especializada, la actual actúa como una ruta altamente selectiva para la migración celular y macromolecular, induciendo la diferenciación celular y actuando sobre el metabolismo del microambiente. En la UDE se distinguen tres zonas, tomando como punto de referencia a la membrana basal 1- la zona más cercana a epidermis, la cual contiene tonofilamentos y hemidesmosomas, los cuales mantienen ancladas las células basales. Esta región se prolonga hasta la lámina densa, 2-la zona intermedia abarca sólo la lámina densa, 3- esta zona se prolonga desde la lámina densa hasta las porciones superiores de la dermis y matriz extracelular. A pesar de que aún existen muchos enigmas moleculares de la UDE, el conocimiento de cada molécula y la función de los distintos compartimentos que la integran, permitirá ampliar los conocimientos fisiopatogénicos de diversas entidades dermatológicas frecuentes en la práctica clínica diaria.

Ultrastructural changes of hepatic stellate cells in the space of Disse in alcoholic fatty liver

BACKGROUND: Hepatic stellate cell (HSC) has been suggested to play a role in fibrogenesis in alcoholic liver disease. We evaluate the correlation with fibrogenesis and ultrastructure of hepatic stellate cells in alcoholic fatty liver. METHODS: We studied 6 patients with alcoholic fatty liver and 5 non-alcoholic fatty liver. The numbers of fat droplets in hepatic stellate cell was determined by electron microscopy. We also studied the grading of deposition of collagen fibers in the space of Disse. We were to evaluate the structure of hepatic stellate cells in the space of Disse by light and electron microscopy. RESULTS: Wider distribution of fat droplets in hepatic stellate cells in alcoholic fatty liver than in normal liver. The hypertrophied endoplasmic reticulum in hepatic stellate cells is a prominent findings in alcoholic fatty liver. We observed basement membrane-like materials in patients with alcoholic fatty liver with hepatic fibrosis. CONCLUSION: The results demonstrate that, in patients with alcoholic fatty liver by alcoholic liver injury, the hepatic stellate cells may play an important role in the fibrogenesis of perisinusoidal spaces in the liver.

Alteraciones de la zona de membrana basal en enfermedades cutáneas / Abnormalities of the basement membrane zone in cutaneous diseases

Diversas enfermedades cutáneas se caracterizan por alteraciones localizadas preferentemente en la zona de membrana basal. Estas dermatosis se han hereditarias y adquiridas. Se pueden encontrar cambios ultraestructurales en la membrana basal, muchos de los cuales serían causados por fenómenos autoinmunes. Múltiples investigaciones han permitido aclarar la morfogénesis de las lesiones clínicamente visibles que afectan esta zona en particular. En la presente revisión se realiza una puesta al día de la última información de la literatura sobre estas interesantes enfermedades

Avances en la estructura y función de la membrana basal / Advances in basement membrane structure and function

La zona de membrana basal es una estructura compleja. Está constituída por la membrana plasmática de la célula basal, lámina lúcida, lámina densa y región de anclaje; cada una de ellas posee diversos componentes moleculares. Sus principales funciones biológicas son actuar como soporte y barrera mecánica, permite la fijación dermoepidérmica, regular la filtración y permeabilidad y guiar la regeneración tisular

Exocrine differentiation of trichoepithelioma & desmoplastic trichoepithelioma; a scanning electron microscopic study.

Trichoepithelioma is widely thought to be a benign appendage tumour which arises from hair follicles (i) Scanning electron microscopy reveals that the basement membrane of Trichoepithelioma & desmoplastic Trichoepithelioma is similar to the basement membrane of exocrine glands like sweat or sebaceous gland. The basement membrane of Trichoepithelioma and desmoplastic Trichoepithelioma do not show any difference in their structure. Thus, possibly Trichoepithelioma and desmoplastic Trichoepithelioma arises from exocrine gland and are closely related to each other.

Ultrastructural changes in esophageal mucosa of chronic tobacco chewers.

Seventeen chronic tobacco chewers and three control subjects underwent clinical evaluation, upper gastrointestinal endoscopy and esophageal mucosal biopsies. The esophageal biopsies were processed and examined under the electron microscope. A large number of ultrastructural abnormalities such as discontinuous, fragmented basement membrane, with reduction in hemidesmosomes, widened intercellular spaces were found in the esophageal mucosa of chronic tobacco chewers which resembled the ultrastructural features of experimental carcinogenesis and leukoplakia. It is concluded that chronic chewing of tobacco produces ultrastructural abnormalities in the esophageal mucosa which could be important precursors for esophageal malignancy.

Nefritis autóloga experimental: estudio morfológico y de permeabilidad capilar en las lesiones glomerulares de ratas / Experimental autologous nephritis: morphological and capilary permeability study in glomerular lesions in rats

En ratas de la cepa Lewis con nefritis autóloga activa (nefritis de Heymann) se estudiaron en secuencia las lesiones ultraestructurales de la pared capilar glomerular. En 19 animales nefríticos inyectados in vivo por vía IV con ferritina aniónica o catiónica se exploraron las modificaciones de permeabilidad de la membrana basal glomerular (MBG) y las modificaciones de las cargas aniónicas negativas de la lámina rara externa. En animales sacrificados a las 8 semanas post-inmunización con leve proteinuria (8.70 mg/24 horas) se observaron aislados depósitos electrodensos en la lámina rara externa con pérdida focal de las cargas negativas en dichos sitios. En animales con proteinuria intensa (60 mg/24 horas) sacrificados entre las 10 y 12 semanas post-inmunización se observaron abundantísimos depósitos electrodensos subepiteliales en la MBG, abundante IgG en patrón granular a la inmunofluorescencia, neoformación "espicular" de membrana y rechazamiento de los diafragmas de filtración. Este grupo de animales mostró incremento de permeabilidad de la MBG a la ferritina aniónica alrededor de los depósitos y diferentes alteraciones (pérdida, distorsión, regeneración y reacomodo) de las cargas negativas fijas de la lámina rara externa de la membrana basal glomerular. La incubación in vitro con ferritina catiónica de glomérulos expuestos en los animales inmunizados, mostró un marcaje adicional de la cubierta polianiónica podocitaria con total integridad de la misma y similar a la de los animales controles