VPA/PLGA microfibers produced by coaxial electrospinning for the treatment of central nervous system injury

The central nervous system shows limited regenerative capacity after injury. Spinal cord injury (SCI) is a devastating traumatic injury resulting in loss of sensory, motor, and autonomic function distal from the level of injury. An appropriate combination of biomaterials and bioactive substances is currently thought to be a promising approach to treat this condition. Systemic administration of valproic acid (VPA) has been previously shown to promote functional recovery in animal models of SCI. In this study, VPA was encapsulated in poly(lactic-co-glycolic acid) (PLGA) microfibers by the coaxial electrospinning technique. Fibers showed continuous and cylindrical morphology, randomly oriented fibers, and compatible morphological and mechanical characteristics for application in SCI. Drug-release analysis indicated a rapid release of VPA during the first day of the in vitro test. The coaxial fibers containing VPA supported adhesion, viability, and proliferation of PC12 cells. In addition, the VPA/PLGA microfibers induced the reduction of PC12 cell viability, as has already been described in the literature. The biomaterials were implanted in rats after SCI. The groups that received the implants did not show increased functional recovery or tissue regeneration compared to the control. These results indicated the cytocompatibility of the VPA/PLGA core-shell microfibers and that it may be a promising approach to treat SCI when combined with other strategies.

Compromiso cardiovascular en el síndrome de Marfan: reporte de caso / Cardiovascular compromise in Marfan syndrome: case report

El Síndrome de Marfan es una enfermedad del tejido conectivo causada por mutaciones en el gen FBN1, mismo que codifica la fibrilina-1, glucoproteína fundamental del componente de las microfibrillas. Entre las manifestaciones clínicas, la afectación cardiovascular merece una consideración especial, debido a su pronóstico. Se presenta un varón de 40 años quien acude al Instituto Nacional del Tórax por un cuadro clínico de 2 años de evolución caracterizado por clínica de insuficiencia cardiaca descompensada, insuficiencia aortica y criterios colagenopatía subyacente, ante lo cual tras los estudios de gabinete y el uso de los criterios pertinentes (Ghent modificados) se llega al diagnóstico de Síndrome de Marfan. La supervivencia de estos pacientes depende del diagnóstico temprano evitando las complicaciones que en su mayoría son mortales, el uso de los scores es de ayuda y la intervención oportuna lleva a un mejor pronóstico de vida y evita los procedimientos invasivos y por ende demás complicaciones

Marfan syndrome is a connective tissue disease caused by mutations in the FBN1 gene, which encodes fibrillin-1, a fundamental glycoprotein of the microfibril component. Among the clinical manifestations, cardiovascular involvement deserves special consideration, due to its prognosis. We present a 40-year-old man who came to the National Thorax Institute for a clinical picture of 2 years of evolution characterized by symptoms of decompensated heart failure, aortic insufficiency and underlying collagenous criteria, before which, after cabinet studies and the use of the relevant criteria (modified Ghent) leads to the diagnosis of Marfan Syndrome. The survival of these patients depends on early diagnosis, avoiding complications that are mostly fatal, the use of scores is helpful and timely intervention leads to a better prognosis for life and avoids invasive procedures and therefore other complications.

Polymorphisms of the BARX1 and ADAMTS17 Locus Genes in Individuals With Gastroesophageal Reflux Disease

BACKGROUND/AIMS: Gastroesophageal reflux disease (GERD) represents a common condition having a substantial impact on the patients' quality of life, as well as the health system. According to many studies, the BARX1 and ADAMTS17 genes have been suggested as genetic risk loci for the development of GERD and its complications. The purpose of this study is to investigate the potential association between GERD and BARX1 and ADAMTS17 polymorphisms. METHODS: The present is a prospective cohort study of 160 GERD patients and 180 healthy control subjects of Greek origin, examined for BARX1 and ADAMTS17 polymorphisms (rs11789015 and rs4965272) and a potential correlation to GERD. RESULTS: The rs11789015 AG and GG genotypes were found to be significantly associated with GERD (P = 0.032; OR, 1.65; 95% CI, 1.06–2.57 and P = 0.033; OR, 3.00; 95% CI, 1.15–7.82, respectively), as well as the G allele (P = 0.007; OR, 1.60; 95% CI, 1.14–2.24). Concerning the rs4965272, only the GG genotype was significantly associated with GERD (P = 0.035; OR, 3.42; 95% CI, 1.06–11.05). CONCLUSIONS: This is a study investigating the potential correlation between BARX1 and ADAMTS17 polymorphisms and the development of GERD, showing a considerable association between both polymorphisms and the disease. This finding suggests that esophageal differentiation or altered regulation on microfibrils in the cell environment could be implicated as possible mechanisms in the pathogenesis of GERD.

A novel FBN1 gene mutation associated with early-onset pneumothorax in Marfan syndrome

Marfan syndrome (MFS) is an inherited connective tissue disorder with a mutation in the fibrillin-1 (FBN1) gene. Fibrillin is a major building block of microfibrils, which constitute the structural component of the connective tissues. A 10-year-old girl visited our hospital with the chief complaint of precocious puberty. According to her medical history, she had a pulmonary wedge resection for a pneumothorax at 9 years of age. There was no family history of MFS. Mid parental height was 161.5 cm. The patient's height was 162 cm (>97th percentile), and her weight was 40 kg (75th-90th percentile). At the time of initial presentation, her bone age was approximately 11 years. From the ophthalmologic examination, there were no abnormal findings except myopia. There was no wrist sign. At the age of 14 years, she revisited the hospital with the chief complaint of scoliosis. Her height and weight were 170 cm and 50 kg, respectively, and she had arachnodactyly and wrist sign. We performed an echocardiograph and a test for the FBN1 gene mutation with direct sequencing of 65 coding exons, suspecting MFS. There were no cardiac abnormalities including mitral valve prolapse. A cytosine residue deletion in exon 7 (c.660delC) was detected. This is a novel mutation causing a frameshift in protein synthesis and predicted to create a premature stop codon. We report the case of a patient with MFS with a novel FBN1 gene missense mutation and a history of pneumothorax at a young age without cardiac abnormalities during her teenage years.

Advances in the research of modulation of dermal collagen fibrin assembly by decorin / 中华烧伤杂志

Formation of dermal collagen fiber is a complicated and sequential process with the progressive assembly of collagen. Collagen monomers form stepped and orderly protofibrils through longitudinal displacement. Subsequently, protofibrils or protofibrils and collagen are bonded by covalent bonds to form orderly lamellar structure of collagen fibers. Then collagen fibers are tightly wound into coarse collagen fiber bundles by covalent crosslinking. Decorin is a multifunctional small leucine-rich proteoglycan. It can prevent the aggregation of protofibrils by binding to the specific site of collagen with its core protein, and adjusting the spacing between the protofibrils with its glycosaminoglycan chain. Thus, by effecting the formation of collagen fibers with regulation of collagen assembly, decorin may help prevent scar formation and even promote regeneration.

The microfibril-elastin fiber system distribution in left atrioventricular valve of the rat / Distribución del sistema de microfibrillas y fibras de elastina en la valva atrioventricular izquierda de la rata

The microfibril-elastin fiber system, an important constituent of the extracellular matrix, was studied in the rat left atrioventricular valve to investigate the interrelationship of oxytalan, elaunin and elastic fibers in left atrioventricular valve morphology. The elastin fibers forms continuous bundles observed along the length of the valve in atrial and ventricular layers and oriented parallel to endothelium. The elaunin and oxytalan fibers are distributed in the thickest fiber bundles along the length of the valve. The thinner fibers which radiated towards both the atrial and spongiosa layers, either as isolated or arborescent fiber bundles were identified as oxytalan fibers. With transmission electron microscopy elastic fibers were seen mainly in the atrial layer. The spongiosa layer was composed of elaunin and oxytalan fibers and ventricular layer showed elaunin fibers arranged in continuous bundles parallel to the endothelium. Both fibrillin and elastin were seen and identified by immunocytochemistry with colloidal gold in the left atrioventricular valve spongiosa and atrial layers. These observations allow us to suggest that the microfibril-elastin fiber system plays a role in the mechanical protection and maintenance of the integrity of the rat left atrioventricular valve.

Fue estudiado el sistema de fibras microfibrillas-elastina, un componente importante de la matriz extracelular, en la valva atrioventricular izquierda de rata, con la finalidad de investigar la interrelación de oxitalán, elaunin y fibras elásticas en la morfología de dicha valva. Las fibras de elastina forman paquetes continuos a lo largo de la valva en las capas atriales y ventriculares, orientadas paralelamente al endotelio. Las fibras de elaunin y oxitalán se distribuyen en haces de fibras más gruesas a lo largo de la valva. Las fibras más delgadas, las cuales se irradiaban hacia las capas atrial y esponjosa, ya sea como haces de fibras aisladas o arborescentes, fueron identificadas como fibras oxitalán. En la capa atrial a través de microscopía electrónica de transmisión se observaron principalmente fibras elásticas. La capa esponjosa estaba compuesta por fibras de elaunin y oxitalán; la capa ventricular mostró fibras de elaunin dispuestas en haces continuos paralelos al endotelio. Tanto fibrilina y elastina se observaron e identificaron por inmunocitoquímica con oro coloidal en las capas esponjosa y atrial de la valva atrioventricular izquierda. Estas observaciones nos permiten sugerir que el sistema de fibras de elastina-microfibrillas tienen participación en la protección mecánica y la mantención de la integridad de la valva atrioventricular izquierda en la rata.

Electron-microscopic Findings of Elastic Fibers in Zebrafish Skin / 대한피부과학회지

BACKGROUND: The zebrafish, Danio rerio, is a small bony fish that has genetic information and organ systems similar to those seen in human beings. The zebrafish has many advantages as an experimental animal model. There have been studies of zebrafish skin, especially epidermis, but there have been no studies about the elastic fibers in zebrafish skin. OBJECTIVE: The purpose of this study was to investigate the age-related, ultrastructural changes seen in the elastic fibers in zebrafish skin using electron microscopy. METHODS: We examined zebrafish skin using elastic tissue stains, the results of which were confirmed with polymerase chain reaction. We observed the ultrastructural features and age-related degenerative changes using transmission electron microscopy. RESULTS: Elastic fibers existed as a band-like layer beneath the epidermal basement membrane in zebrafish skin, which consisted of electron-dense homogeneous core material and microfibrils surrounding it and scattered inside. Elastic fibers were prominent and compact at 30 days post-fertilization. However, with aging, they started to develop small cysts and lacunae, and finally became fragmented and cracked. CONCLUSION: In zebrafish skin, elastic fibers exist beneath the epidermal basement membrane and, similar to human elastic fibers, show morphologic changes with age. Therefore, this study suggests that zebrafish skin may be useful in elastic tissue research.

A Case of Idiopathic Fibrillary Glomerulonephritis with Hypocomplementemia / 대한신장학회지

A 72-year-old woman presented with generalized edema and proteinuria. Renal biopsy disclosed highly organized fibrillary deposits in subendothelial area by electron microscopy. The microfibrils were 14 nm in diameter and randomly arranged. They did not have a microtubular appearance. These materials were negative for Congo red staining. Cryoglobulinemia or paraproteinemia including light chains was not found. So we can diagnose her as fibrillary glomerulonephritis (GN). In fibrillary GN serum complement levels are usually normal except in rare cases with systemic disease. Here we present a rare case of fibrillary GN with unusual hypocomplementemia.

Morphological and Biochemical Changes in Bone-to-tendon Insertion Site after Achilles Tendon-Bone Graft in Rabbits / 대한정형외과연구학회지

Allografts or autografts of bone-tendon unit has been used widely for ligament or tendon reconstruction of ligament injuries or ligament deficiencies after limb salvage operation to treat malignant bone tumors around joints. While the remodeling process of the ligament or tendon itself after allograft or autograft and the microscopic and biomechanical changes of tendon- bone graft interface have been widely investigated, little is known about the ultrastructural and biochemical changes of the transitional zone in tendon-bone junction. This study was performed to analyze the morphological changes by microscopic (part I), and ultrastructural, and biochemical remodeling of the transitional zone after tendon-bone auto- and allo-grafting (part II). Preliminary, a microscopic studies at bone to tendon insertion site was done as control (part I). And as an experimental work (part II), a total of twenty four rabbits were divided into two group. In 12 animals (allograft group), an Achilles tendon-bone unit was taken with tenotomy 3 cm proximal to calcaneal attachment and osteotomy 5mm distal to the attachment site. This unit was preserved below -70degrees C for 2 weeks and then it was transplanted to another rabbit. In the other 12 animals (autograft group), the Achilles tendon-bone unit was harvested with the same maneuver from one side and transplanted to the other side of the rabbit. After operation, their legs were immobilized with short leg cast for 4 weeks, and then mobilized freely. Four animals in each group were sacrificed at four, eight and sixteen-weeks after transplantation, and their grafted Achilles tendon-bone interfaces were used for analysis of the ultrastrucural and biochemical changes. The following results were obtained. Part I: We conducted an experiment (part I) to investigate the histologic chronologic changes of tendon to bone fixation using the Cole's method and the role of periosteum to the tenodesis. The periosteum around the tenodesis was excised in group I, but it was incised longitudinally and sutured to tendon in group II. As a result, the tendons in the marrow cavity of tibia were firmly fixed by fibrosseous metaplasia in group I at 8 weeks after experiment, but not formed the fibrocartilagenous layer in both groups as a transitional zone of internal stress transmission from tendon to bone in normal tendon, and the group II show the firm connection between sutured periosteum and transferred tendon by external calluses after 3 weeks. These mean the periosteum should be sutured over the inserted tendon to get the early rigid fixation by the induction of external callus around the edges of the tendon to bone insertion. Part II: Histologically in part II experiment, new cartilage cells were observed at postoperative 16 weeks with locally presence of faint tidemark in the autograft group but not in the allograft group. Complete histological remodeling of the transitional zone had not restored both groups.. Ultrastructural analysis revealed no definite differences, but showed time-related restoration of fibers and fibroblasts between both groups except the slightly rapid appearance of parallelism and cross-striation of microfibrils in the autograft group. From biochemical analysis, type I collagen was increased in its concentration, and an early rapid increase of type III collagen and glycosaminoglycan was also observed. In conclusion, these data suggested that type III collagen and glycosaminoglyan are important in stabilization of grafted tendon-bone unit, especially in the transitional zone. The histological and biochemical changes in allograft group were relatively similar to that of autograft group although the allograft group showed the delayed pattern of remodeling. And so the tendon-bone allograft could be used as a good but second substitute followed by autograft.

Structural characterization and distribution of elastic system fibers in the human prostate and some prostatic lesions

Prostatic disorders are accompanied by extensive but poorly understood modifications of the cells and surrounding extracellular matrix. In this study, we examined the distribution of the elastic system fibers in prostatic disorders compared to normal tissue. Sections of prostatic transurethral resections and/or radical prostatectomies were examined after staining with hematoxylin-eosin plus fluorescence microscopy and after Weigert's staining for elastic fibers. Transmission electron microscopy was used to examine the ultrastructure of tissues from radical prostatectomy. A concentric fibrous extracellular matrix and smooth muscle cells were observed surrounding normal acini. The elastic fibers were thin and inconspicuous. In benign prostatic hyperplasia (BPH) the elastic components were of variable thickness and formed a three-dimensional network at the base of the epithelium. Conversely, increased variability in the elastic fiber distribution was observed in adenocarcinomas, depending on the tumor grade. In adenocarcinomas with little differentiation, in some hyperplasic acini, and in the stroma adjacent to tumoral mass, ruptured and residual elastic fibers indicative of matrix degradation or remodeling were seen. In more undifferentiated tumors, a pre-elastic network, perhaps indicative of a new extracellular matrix microenvironment was seen. These results indicate that prostate cancer cell invasion involves extensive remodeling of the fibers of the elastic system.

Estudo histoquímico de fibras oxitalânicas no ligamento periodontal de ratos normais e submetidos a forças mecânicas excessivas / Histochemical study of oxytalan fibers in the normal and repaired periodontal ligament of rats submitted to an excessive mechanical force

Os incisivos inferiores de sete ratos foram comprimidos um contra o outro por 7 dias para detectar a fibra oxitalânica na reparaçäo do ligamento periodontal. Retirados os aparelhos, três animais foram sacrificados imediatamente e os outros em 7, 14, 28 e 52 dias. Foi demonstrado, por histoquímica, que a força mecânica empregada promoveu a degeneraçäo do ligamento periodontal. As fibras oxitalânicas apresentavam-se aumentadas no período de reparaçäo, principalmente após 28 dias. Portanto, essas fibras podem ter um importante papel no suporte do ligamento periodontal normal em em reparaçäo

Avaliaçäo histológica e molecular dos grandes vasos de base em portadores de valva aórtica bicúspide / Histologic and molecular evaluation of the great vessels in patients with bicuspid aortic valve disease

Esta investigaçäo avaliou, através de microscopia ótica, as alterações histológicas nos grandes vasos da base em portadores de valva aórtica bicúspide (VAB) e valva aórtica pulmonar (AP) de 20 portadores de VAB, 11 portadores de VAT e 21 espécimens de indivíduos sem doença cardíaca. As alterações histológicas foram classificadas de 1 a 3 de acordo com sua intensidade. Na AA, a necrose cística da média (p<0,0001), a fragmentaçäo elástica (p=0,0020) e a alteraçäo na orientaçäo das células musculares lisas (p=0,0017) foram significativamente mais intensas (moderadas a graves) nos portadores VAB. Na AP, essas mesmas alterações histológicas também foram mais intensas no grupo VAB (p<0,0001,p=0,0304 e p=0,0420, respectivamente). Posteriormente, empregou-se imunofluorescência indireta e análise computadorizada das imagens para a quantificaçäo de fibrilina-1 e elastina na camada média dos grandes vasos, expressas como densidade óptica integrada média (DOI). Foram avaliados espécimens de 24 portadores aórticos e 6 de artéria pulmonar provenientes de indivíduos sem doença cardíaca. Os portadores de VAB apresentaram reduçäo significativa de fibrilina-1 na AA (p=0,0017). Näo foi observada diferença significativa na quantidade de elastina na AA (p=0,09597) e AP (p=0,09374), bem como associaçäo entre a reduçäo de fibrilina-1 e a idade dos portadores de VAB (p=0,887). Conclui-se que os portadores de VAB apresentaram alterações hsitológicas mais intensas nos vasos da base que os portadores de VAT, principalmente necrose cística da camada média. Na aorta ascendente, essas alterações histológicas podem estar associadas à reduçäo significativa de fibrilina-1 e näo associadas à idade. A reduçäo de fibrilina-1 ocorreu, provavelmente, na matriz extracelular

A Histopathological Study on the Production of Exfoliation Material in Eyes with Exfoliation Syndrome

The hallmark of exfoliation syndrome is the appearance of white granular deposits and dandruff-like flakes on the lens,iris and angle. The incidence of glaucoma is high,and due to zonular weakening, complications are likely to occur in cataract surgery. A histopathological study with electron microscopy was performed on the iris and conjunctival tissue in order to clarify the production process of exfoliation material in the eyes with exfoliation syndrome. The materials were obtained from 13 eyes with exfoliation syndrome during surgery for glaucoma or cataract. The clumps of microfibrils were observed in the extracellular matrix, and the exfoliation materials were closely related with microfibrils.It was found that the basic unit of the exfoliation materials was microfibril. The cellular degenerations were observed in the basement membrane of capillary endothelium, especially the cells near the iris vessels. The exfoliation materials were observed around the degenerated cells; the mature or immature exfoliation materials around the iris melanocyte which show the various degrees of degeneration. The more degeneration and melting of the cells, the larger amount of exfoliation materials. This study suggests that the exfoliation materials in the eyes with exfoliation syndrome are derived from the abnormal microfibril, abnormal basement membrane, and degenerated cell itself.

Morphological and Biochemical Changes of Transitional Zone after Achilles Tendon-bone Autogenous and Allogeneic Graftin Rabbitis Achilles Tendon-bone Autogeous and Allogeneic Graft in Rabbits / 대한정형외과연구학회지

Allografts or autografts of bone-tendon unit have been used for ligament injuries or deficiencies after limb salvage operation for malignant bone tumors around joints. While the remodeling process of the ligament or tendon of the allograftor autograft and the microscopic and biomechanical changes of tendon-bone graft interface have been widely investigated, little is known about the ultrastructural and biochemical changes of the transitionall zone in tendon-bone junction. This study was performed to analyzed the ultrastructural and biochemical changes of the transitional zone after tendon-bone auto-and allo-grafting. A total of twenty four rabbits were divided into two group. In 12 animals(allograft group), two Achilles ten-don-bone unit per each animal were taken and transplanted to another rabbit after preservation below -70degrees C for 2 weeks. In the other 12 animals(autograft group), the Achilles tendon-bone unit was harvested from one side and transplanted to the other side of the rabbit. After operation, their legs were immobilized with short leg cast for 4 weeks, and then mobilized freely. Four animals in each group were sacrificed at four, eight and sixteen-weeks after the transplantation, and their grafted Achilles tendon-bone interfaces were used for analysis of the ultrasturctural and biochemical changes. The following results were obtained. 1. Histologically new cartilage cells were observed at postoperative 16 weeks with local presence of faint tidemark in the autograft group but not in the allograft group. Complete remodeling of the transitional zone had not observed histologically in both groups. 2. Ultrasturctural analysis revealed no definite differences between both groups. However, the slightly rapid appearance of parallelism and cross-striation of microfibrils in the autograft group and time-related restoration of fibers and fibroblasts were observed. 3. From biochemical analysis, type I collagen concentratin was increased, and an early rapid increase of type III collagen and glycosaminoglycan were also observed. In conclusion, these data suggested that type III collagen and glycosaminoglycan are important in stabilization of grafted tendon-bone unit, especially in the transitional zone. The histological and biochemical changes in allograft group were relatively similar to that of autograft group although the allograft group showed the delayed pattern of remodeling. Therefore, the tendon- allograft could be used as a good substitute for the autograft for tendon or ligament reconstruction when no suitable autograft is available.

Ultrastructural Changes of the Rabbit Lens Fiber Cells in Cataract

This study was carried out to investigate the ultrastructural changes of lens fiber cells, length of gap junctions, and distribution of proteoplycans in cataractous lens. The cataract was induced by stabbing the posterior surface of the lens with 25 gauge needle. The lens were obseved by electron microscopy with estimation of the gap junction. Alcian blue stain was performed for examination of proteoglyscas. The results were as follows. Characteristic changes of the cataractous lens fiber cells were swelling and condensation of the cytoplasm, alterations of cytoplasmic granules including changes of density and size of cytoplasmic granules, and formation of microfibrills, high electron-dense amorphous substance, electron-dense particles, variably sized globular bodies, and multilamellar bodies. The lengths of gap junctions were 2.51+/-1.09um in control and 1.06+/-0.33um in cataractous lens fiber cells(P<0.001). Proteoglycans showing high electron-dense amophorous substance were distributed in the intercellular spaces along the cytoplasmic membrane in control group, but disapperaed in cataractous lens fiber cells. According to these results, it is conceivalble that the changes of the gap junctions and proteoglycans were closely related to the pathogenesis of cataract.

A Study on the Development of the Thoracic Aorta in Human Fetus / 체질인류학회지

Prenatal development of the thoracic aorta of the human during the period ranging from gestation weeks 7 (C-R length 20mm) to 30 (C-R length 260mm) was examined by transmission electron microscopy and the following results were obtained. The early form of cuboidal or columnar endothelial cells at 7-9 weeks of gestation changed gradually to typical flat endothelial cells at 12-14 weeks of gestation. At 9 weeks of gestation, the mesenchymal cells begin to differentiate to myoblasts, which have small clusters of myofilaments with dense bodies and rough endoplasmic reticulum. And from 14 weeks the differentiating cells begin to form a parallel concentric lamellar structure. At 12th week of gestation, elastic fibers were first seen in subendothelial connective tissue and the intercellular spaces between smooth muscle cells. Elastic fibers appeared as small globular shape which composed of a central core of elastic and peripheral microfibrils. From this period the amount of elastic fibers and their aggregation increases gradually in both the subendothelial space and the intercellular spaces between smooth muscle cells. At 30th week of gestation, subendothelial elastic fibers almost completed the internal elastic lamina and also well formed elastic laminae were seen between the smooth muscle cells adjacent to endothelial cells. However, in the space between the smooth muscle cells near the adventitia the elastic lamina formation is delayed. In the adventitia elastic fiber were scanty but collagen fibers are abundant.

Histopathological Study of Extraocular Musele followinr Posterior Fixation Suture in Rabbits: Pathogenesis of Musele Fibrosis

The authors observed the histological and ultrastructural findings in a study of the fibrosis of the extraocular muscles following a posterior fixation suture in rabbits. the early findings demonstrated hyalinosis, clumping of the nuclei of muscle cells and collagenization of the muscle tissue. However, there was no evidence of collagen tissue in the degenerated muscle fiber, reserving cell membrane and basement membrane ultrastructurally. The late findings showed splitting and irregular stain of the muscle fibers, many nuclei of presumed muscle cell and filamentous structure at the collagen tissue in the extracellular space. Electron microscopic study showed atrophy and angulation with distortion of the myofibrillar matrix, along with other cytoplasmic degenerative phe nomena in the muscle fibers. Clumps of the well-arranged microfibrils(Mf) and irregularly arranged Mf with fine granular materials(FGM) were adjacent to the immature collagen fibrils. Many of the Mf and FGM were closely associated, and the number of the Mf and FGM decreased with the degree of maturity of the collagen fibrils. The anatomical structure of the myofibrill was identified as that of the Mf. From these findings, it would appear that formation of collagen fiber occurs in the extracellular space and that Mf and FGM are primarily responsible for the formation of the collagen fibils.

The Role of Microfibril in Pathogenesis of Exfolion Syndrome

We electron-microscopically studied 15 specimens of upper limbal conjunctiva obtained from 14 patients with exfoliation syndrome and clinical evidence of glaucoma. Of 15 specimens, four(three patients) contained exfoliation materials in the stroma of the stroma of the conjunctiva. These exfoliation materials of immature, intermediate, and mature forms were composed of abnormal microfibrils lying adjacent to the fibroblasts and located in close proximity to the elastic and collagen fibers. These observations suggest a sequence of events by which microfibrils develop into exfoliation materials.

Microtubules and microfibrils of the rabbit ciliary epithelium

Microfibrils and microtubules are present in the ciliary epithelium of the rabbit ciliary processes. The membranous walls of both the microfibrils and microtubules have a thickness of ca 85 A. The outside diameter of the microtubules is 270 A and the inside diameter 100 A. Fibrils, branching and non-branching, are seen in an association with ribosomes, mitochondria and plasma membranes, and apparently continuous with zonula fibers extracellularly. Similar associations exist for the microtubules although the comparative brevity in length indicated that they experience a more tortuous cytoplasmic course than do the micro-fibrils. The attachment and secretory functions of the ciliary body may be accomplished by these cytoplasmic components through [1] transcytoplasmic contractility, [2] cellular skeletal support, and [3] transport of liquid elements, ions and small molecules