Autophagy is an important homeostatic cellular recycling mechanism responsible for degrading injured or dysfunctional subcellular organelles and proteins in all living cells. The process of autophagy can be divided into three relatively independent steps: the initiation of phagophore, the formation of autophagosome and the maturation/degradation stage. Different morphological characteristics and molecular marker changes can be observed at these stages. Morphological approaches are useful to produce novel knowledge that would not be achieved through other experimental methods. Here we summarize the morphological methods in monitoring autophagy, the principles in data interpretation and the cautions that should be considered in the study of autophagy.
Autophagy ; Homeostasis ; Humans ; Organelles ; Phagosomes

Experimental retinal changes of intraperitoneal copper sulphate administration were studied with the electron microscope. Rabbits were given intraperitoneally copper sulphate in doses of 2.5 mg every day. The results were as follows: 1. Swelling and degeneration of inner segment of the photoreceptor cells were observed after 4 weeks of copper administration. There were no chages in the pigment epithelium. 2. Phagosomes, phagoyslosomes and melanolysosomes were observed in the pigment epithelium and subretinal space after 6 weeks of copper administration. 3. Copper sulphate primarily involved the rod and cone layer and the changes of the pigment epithelium were late and secondary. These findings were similar with those of the retintis pigmentosa.
Copper* ; Epithelium ; Phagosomes ; Photoreceptor Cells ; Rabbits ; Retinaldehyde*

Retinal changes of rabbit after intraocular injection of lidocaine(group I), lidocaine-epinephrine 1:50,000 (group II), and normal saline (group III) were studied with electron microscope. The results were as follows: 1. Intracellular edema of the cells of the inner nuclear layer and the inner one third of the outer nueler layer was observed. 2. The photoreceptor outer segments showed mild fragmentation. 3. Swelling of mitochondria and several phagosomes were observed in the cytoplasm of the pigment epithelium. 4. Above changes were reversible during the observation period of one week. 5. No significant differences between the groups I, II, and III were noted.
Cytoplasm ; Edema ; Epithelium ; Injections, Intraocular* ; Lidocaine* ; Mitochondria ; Phagosomes ; Retina* ; Retinaldehyde

An experimental study was performed on 16 rabbits to evaluate the toxicity of benzalkonium chloride(BAK) on the corneal endothelium. Each rabbit received two drops of 0.01% BAK in the right eye and BSS in the left eye as control. The rabbits were divided into 4 groups: instillation of BAK 20 times at 6-minute intervals in normal cornea(group 1), instillation of BAK 40 times at 3-minute intervals in normal cornea (group 2), instillation of BAK 20 times at 6-minute intervals in de-epithelized condition with the size of 6mm diameter(group 3) and instillation of BAK 40 times at 3-minute intervals in deepithelized cornea(group 4). After the last instillation of BAK, histopathologic examination was performed with electron microscope. Group 1 showed nearly normal corneal endothelial findings, but group 2, 3 and 4 showed enlarged rough endoplasmic reticulum, partially distrupted Goigi apparatus and mitochodria, the presence of vacuoles and phagosomes. Group 4 showed severe destruction of subcellular structures. The results of this study indicate that an exaggerated use of topical drug containing 0.01% BAK may induce corneal endothelial damage, especially when the epithelium was already damaged.
Benzalkonium Compounds* ; Cornea ; Endoplasmic Reticulum, Rough ; Endothelium, Corneal* ; Epithelium ; Phagosomes ; Rabbits* ; Vacuoles

Autophagy is an important homeostatic cellular recycling mechanism responsible for degrading injured or dysfunctional cellular organelles and proteins in all living cells. Aging is a universal phenomenon characterized by progressive deterioration of cells and organs due to accumulation of macromolecular and organelle damage. Growing evidences indicate that the rate of autophagosome formation and maturation and the efficiency of autophagosome/lysosome fusion decline with age. Dysfunctional autophagy has also been observed in age-related diseases. Autophagy disruption resulted accumulation of mutated or misfolded proteins is the essential feature of neurodegenerative disorders. However, in cancers, fibroproliferative diseases or cardiovascular diseases, autophagy can play either a protective or destructive role in different types of disease, and even in different stages of the same disease. The review will discuss the cellular and molecular mechanisms of autophagy and its important role in the pathogenesis of aging and age-related diseases, and the ongoing drug discovery strategies for therapeutic intervention.
Aging ; Autophagy ; Drug Discovery ; Humans ; Lysosomes ; metabolism ; Neurodegenerative Diseases ; Phagosomes ; metabolism ; Protein Folding

This study was carried out to investigate diurnal changes of lysosomes includ ing ultrastructural changes of phagosomes and activity of acid phosphatase in the phagosomes and diurnal biochemical changes of cathepsin D activity of rab bits. The eyes were obtained at 0:00, 4:00, 8:00, 12:00, 16:00 and 20:00 o'clock. The number of lysosomes and phagosomes in retinal pigment epithelium(RPE) was the highest at 8:00 o'clock, thereafter decreased with time. There were three types of phagosomes; fresh phagosomes showed both negative and positive reactions, lamellar bodies positive, and dense bodies partially positive. The biochemical activity of cathepsin D was the highest at 8:00 o'clock consistent with the time of peak in phagocytic activities of RPE. According to the above results, it would be suggested that the maximum shedding of outer segments and phagocytic activity of RPE occurred on the early stage after sunlight exposure, and that the phagosomes were degraded to the lamellar bodies and dense bodies sequentially. And also activity of the cathepsin D would be increased consistent with the phagocytic activity of RPE.
Acid Phosphatase ; Cathepsin D ; Lysosomes ; Phagosomes ; Retinal Pigment Epithelium* ; Retinaldehyde* ; Sunlight

Phagocytosis and morphologic changes in the retinal pigment epithelial cell (RPE) were observed after subretinal injection of latex microspheres. Latex microspheres were injected into the subretinal space in the posterior pole of black rabbits through the scleral incision. Five weeks after injection, we enucleated 5 eyeballs which did not show any vitreous or retinal hemorrhage by indirect ophthalmoscopic examination. Choroid and retina of injec-tion site was excised and processed to observe under the transmission electron microscope. The RPE contained numerous latex phagosomes, phagolysosomes, and phagomelanosomes in their cytoplasms. RPE hyperplasia and subretinal membrane were found. These findings suggest that the pathologic response of the RPE, such as proliferation, occur when retinal pigment epithelial cells phagocytize indigestible materials or their intracellular accumulation of phagosome become excessive.
Choroid ; Cytoplasm ; Epithelial Cells* ; Hyperplasia ; Latex ; Membranes ; Microspheres* ; Phagocytosis ; Phagosomes ; Rabbits ; Retina ; Retinal Hemorrhage ; Retinal Pigment Epithelium ; Retinaldehyde*

The ultrastructural changes of the chorioretina following the intravitreal injection of ornithine in rabbit eyes at 1,2,4,8 week time intervals were investigated employing electron microscopy in this animal experiment. 1. 1 week after injection, swelling of the mitochondria in the cytoplasm of the pigment epithelium was seen. 2. 2 weeks after injection, phagosomes and phagolysosomes were present in the cytoplasm of the pigment epithelium and nerve elements in the inner nuclear layer disappeared and were replaced by Muller cell. 3. 4 weeks after injection, stroma of the choroid was atrophied and abundant melanocytes were aggregated, and papillary formed pigment epithelium with detachment of the retina was seen. 4. 8 weeks after injection, stromal atrophy and attenuated choriocapillaries of the choroid were present, and proliferation of the microvilli of the pigment epithelium after detachment of the retina was seen. 5. In summary intravitreal injection of ornithine in rabbits initially caused marked changes in the pigment epithelium with subsequent degeneration of the choroid and sensory retina.
Animal Experimentation ; Atrophy ; Choroid ; Cytoplasm ; Epithelium ; Intravitreal Injections ; Melanocytes ; Microscopy, Electron ; Microvilli ; Mitochondria ; Ornithine* ; Phagosomes ; Rabbits ; Retina

Congenital self-healing reticulohistiocytosis (CSHRH) is a rare Langerhans cell disorder usually showing spontaneous resolution within 3-4 months. By electron microscopy, the identification of Birbeck granules and laminated dense bodies in the infiltrated cells is mandatory for the diagnosis of CSHRH. However, in some reported cases, Birbeck granules could not be demonstrated and only cytoplasmic dense bodies were seen. If the lesion is more advanced, Birbeck granules are transformed to lysosomes, i.e., 'unique phagosomes', in which they are degraded. A 2-month-old Korean girl presented with congenital, numerous red-brown pigmented papules on the left side of trunk and upper extremity without systemic symptoms. A biopsy specimen demonstrated papillary dermis containing epidermotropic infiltrates of histiocytes with abundant eosinophilic cytoplasm. Some had kidney-shaped nuclei and PAS-positive cytoplasmic inclusions. Immunohistochemically, infiltrating cells expressed S-100 protein and ultrastructurally, no Birbeck granules but many dense laminated bodies and unique phagosomes were found. It was ten months since the skin lesions developed that they have started resolving.
Biopsy ; Cytoplasm ; Dermis ; Diagnosis ; Eosinophils ; Female ; Histiocytes ; Humans ; Inclusion Bodies ; Infant ; Lysosomes ; Microscopy, Electron ; Phagosomes ; S100 Proteins ; Skin ; Upper Extremity

Light and electron microscopic studies were performed to investigate the subcellular alterations of lymphocytes in rat Peyer's patches by dehydration. Sprague -Dawley rats weighing 210 to 230 gm were fed with dried diet and without water for 5, 7, 9, or 13 days. In light microscopy, the lymphocytes with very dark nucleus and/or cytoplasmic materials are shown in Peyer's patches of the dehydrated rats. The number of these lymphocytes were increased according to the degree of dehydration. Some dark nuclei were C or O shaped, and some cells with dark nucleus showed the light or empty cytoplasm as halo. The number of Tunel -positive lymphocytes were increased according to the duration of dehydration, and lymphocytes with Tunel -positive nucleus appeared in a group. some cells included the Tunel - positive nuclei and materials in their cytoplasm. Especially the cells of 13 day -dehydrated group had the strongly positive nucluei. In electron microscopy, the nuclei of lymphocytes shown very dark in light microscopy were condensed and/or fragmented. The aspects of nuclear condensations were various; simply condensed, rosary -like, crescentic or irregular. The destructions of cytoplasmic organelles were increased according to the degree of the dehydration. Many cells contained the phagosomes and necrotic and/or apoptosis -like cell debris, and the number of foreign body containing cells were increased according to the duration of the dehydration. These results showed that a number of lymphocytes were destructed by the necrosis and apoptosis -like mechanism morphologically, and the number of the cells containing these destructed cell debris are increased according to the duration of dehydration.
Animals ; Apoptosis ; Cytoplasm ; Dehydration* ; Diet ; Foreign Bodies ; In Situ Nick-End Labeling ; Lymphocytes* ; Microscopy ; Microscopy, Electron ; Microscopy, Electron, Transmission ; Necrosis ; Organelles ; Peyer's Patches ; Phagosomes ; Rats*