Abstract: The ultrastructure of immature exo-erythrocytic forms of Plasmodium berghei in rat hepatocytes was studied at stages between 25 and 51 h of development. A new method was successfully applied to localize the parasites in a small portion of the liver by temporary ligature of blood vessels to the majority of the liver, and from the spleen and the pancreas. Nuclear profiles appeared to be part of a highly lobed nuclear reticulum. Peripheral vesiculation and vacuolization of the cytoplasm was increasingly prominent and ushered in the formation of pseudocytomeres. Spacing between host- and parasite-derived membranes could first be observed after 43 h of development. In general, organellar development was found to follow closely that described for plasmodial oocysts.

Abstract: Treatment of cultured muscle cells with the inhibitors of lysosomal function, leupeptin, and chloroquine, decrease the degradation of acetylcholine receptors (AChR) and causes accumulation of undegraded receptors intracellularly. Under these conditions the number of cytoplasmic coated vesicles, i.e. structures that appear to transport this receptor within the cultured muscle cell, increases in parallel. This study investigates the effects of leupeptin and chloroquine on the morphology of cultured myotubes in order to learn more about the turnover of acetylcholine (ACh) receptors and the origin of the coated vesicles. Chloroquine causes involution of the plasma membrane, disorganization in the arrangement of sarcomeres, vacuolization, and enlargement of dense lysosome-like bodies in myotubes. The diameter of dense bodies in untreated myotubes is 0.36 ± 0.01 μm (mean ± SEM) compared with 2 ± 0.12 μm after 48 h of incubation with chloroquine. Leupeptin does not disrupt the normal architecture of sarcomeres and does not cause vacuolization of the myotubes. However, leupeptin does enlarge the dense bodies, although to a lesser extent than chloroquine (average diameter after 48 h treatment, 1.0 ± 0.06 μm, p < 0.01). Untreated myotubes appear to contain equal numbers of large and small coated vesicles. After chloroquine treatment 95% of coated vesicles are large (80–120 nm in diameter), whereas after leupeptin treatment the majority of coated vesicles are small (40–70 nm in diameter). After incubation with horseradish peroxidase (HRP) 62% ± 9 of coated vesicles in chloroquinetreated cells contain the tracer, whereas in control cells only 11% ± 4 of coated vesicles contain HRP reaction product. These observations indicate that chloroquine causes accumulation of coated vesicles and interferes with degradation of AChR by preventing fusion of lysosomes with coated vesicles originating by endocytosis.

Abstract: The brains of neonate albino rats were examined with the light and electron microscope following subcutaneous administration of monosodium glutamate (MSG). In addition to lesions in areas known to be vulnerable to glutamate, such as the arcuate nucleus of the hypothalamus, distinct areas of necrotic tissue were detected in the granular portion of the retrosplenial cingulate cortex. The affected cells display the cytological features characteristic of MSG-lesioned brain tissue, including vacuolization of the endoplasmic reticulum and clumping of chromatin. Numerous pyknotic nuclei can be detected as early as 3 h following treatment. The possible causes of the lesion, particularly the role that may be played by astrocytes, are discussed.

Abstract: A single large dose (200 mg/kg) of cyclophosphamide (Cy) caused thymic involution. Thymic cortex was almost depleted of lymphocytes while medullary thymocytes were not affected. This resulted in thymic inversion on day 4. During the period of involution the cortex was invaded by positive acid phosphatase granules containing macrophages. Later the cytoplasms of these macrophages were loaded with lipid droplets and residual materials. Extensive vacuolization of the cytoplasms of epithelial and special cells were revealed. Regeneration began on day 4. Repopulating cells appeared primarily in subcapsular region. Regeneration was complete by day 11 as examined by morphological technics. While FCS dependent rosette formation capacity remained below the control level even on day 16.

Abstract: Studies of a new Japanese case of incontinentia pigmenti achromians were made by electron microscopy. At the periphery of the depigmented lesions, the melanocytes had several subcellular abnormalities; i.e., vacuolization of the cytoplasm, aggregation of melanosomes, and autophagic vacuoles. Many non-specific basal dendritic cells could be identified as non-pigment producing melanocytes. The depigmentation in this disease seemed to have been caused by both melanocyte degeneration and inactivation. Numerous nerve endings were seen in close contact with the basal lamina of the epidermis or even within the epidermis. Direct contacts between melanocytes and free nerve endings were presumed when a direct continuity between the Schwann cell basal lamina of the nerve ending and the basal lamina of melanocytes was observed. It was further observed in this study that nerve endings could be found associated with either normal or degenerated melanocytes. Apparently normal melanocytes in the lesion may not be entirely normal in function.

Abstract: Chloroplasts in leaf cuttings of Nicotiana rustica L. show swelling of the thylakoid system and formation of plastid vacuoles in the light. These ultrastructural changes may be caused by uptake of K+ and Cl- into the aqueous compartments between the thylakoid membranes. Ion changes arid ultrastructural alterations are reversible in darkness.

Abstract: The influences which are known to be caused by styrene on the human body are stimulation of the mucosal membrane and atrophy of the central nervous system. There are several clinical reports and animal experiments concerning the stimulation of the mucosal membrane, and styrene is presumed to stimulate the mucosal membrane of the nose. To the best of our knowledge, however, there have been no reports describing histological pathology of the mucosal membrane of the nose induced by exposure to styrene. Accordingly we made animal experiments using rats in order to see influences of styrene on the mucosal membrane of the upper and lower respiratory tracts including the mucosal membrane of the nose, and could confirm the following changes electron-microscopically: 1. Increases in the amount of mucous adhering to cilia, 2. Occasional formation of compound cilia, 3. Appearance of substances having a higher electron-microscopic density within the cytoplasm of various epithelial cells, 4. Degeneration of secretory granules of goblet cells--changes in electron-microscopic density, appearance of cores with a higher electron-microscopic density, 5. Nuclear pyknosis, 6. Vacuolization of various epithelial cells, and 7. Separation and falling-off of the epithelial cell layer.

Abstract: A systematic study of a series of thirty bilateral biopsies of testes was performed using electron microscopy. Observations showed how frequently there were bilateral changes within the Sertoli cells. These included a sometimes extensive vacuolization of the endoplasmic reticulum which may cause germ cells to exfoliate. Bilateral vascular lesions including modifications of the capillary endothelium which becomes thick and rich in pinocytotic vesicles and arteriolar spasms with an increase in number of microfilaments in the endothelial cells were constantly observed.

Abstract: Heart lesions induced in mice, rats, rabbits and dogs by Doxorubicin administered i.v. according to various schedules were studied by light and electron microscopy. Vacuolization of myocardial cyto...