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Biomedical subjects

C Oliver

Publications and source records attributed to C Oliver.

At least 379 records · Page 21Linked to original sources

Formation of anomalous lysosomes in monocytes, neutrophils, and eosinophils from bone marrow of mice with Chédiak-Higashi syndrome.

Chédiak-Higashi syndrome, a rare autosomal recessive disorder occurring in man, beige mice, and other homologues, is characterized by abnormally large lysosomes in many cell types. The formation of these anomalous lysosomes in developing monocytes, neutrophils, and eosinophils in beige mouse bone marrow, as well as lysosomal formation in the corresponding normal cells from C57 Black mice, was investigated by electron microscopy, together with a method for the demonstration of peroxidase activity. Localization of peroxidase reaction product was the same in both C57BL and beige mice. In promonocytes and in neutrophilic and eosinophilic proganulocytes, peroxidase reaction product was localized in lysosomes, in the perinuclear cisternae, all cisternae of the endoplasmic reticulum, and the Golgi succules. In the later stages of development, reaction product was localized only in the lysosomes. In promonocytes and progranulocytes from the C57BL mice, lysosomes apparently form from the inner Golgi succule. Fusion of newly formed lysosomes was occasionally seen. Lysosomal fusion was never observed in the more mature monocytes and eosinophils and was only rarely seen in mature neutrophils. In the beige mouse, lysosomes were formed as in the C57BL mice. However, in the beige mouse, fusion of newly formed lysosomes occurred frequently in promonocytes and neutrophilic progranulocytes. Lysosomal fusion was also frequently observed in the more mature cells. As a result of the continued lysosomal fusion, the mature monocytes, neutrophils, and eosinophils from the beige mouse contained fewer but often greatly enlarged lysosomes.

Animals↗

Fate of exogenous peroxidase in renal lysosomes of mice with Chediak-Higashi syndrome.

The beige mouse is a homolog of Chediak-Higashi syndrome, a disorder which is characterized by the presence of enlarged (anomalous) lysosomes in many cell types. In kidney, anomalous lysosomes are present in cells of the proximal convoluted tubules. In this study, the degradation of injected horseradish peroxidase (HRP) in lysosomes was studied in both the convoluted (S1-S2) and straight (S3) segments of the proximal tubules of beige and control (C57 B1) mice. Tissues were removed at intervals from 18 hours to 7 days after HRP injection. Peroxidase activity was visualized for light and electron microscopy by incubating sections in diaminobenzidine medium. No differences in the rate of degradation of HRP were demonstrable between anomalous lysosomes in S1-S2 cells of beige kidney and those in controls. In both animals, HRP was demonstrable in these lysosomes at 18 and 36 hours but not at 48 hours after injection. By electron microscopy, reaction product appeared as a flocculent precipitate distributed uniformly throughout the lysosome. In contrast to those of S1-S2 cells, lysosomes of beige S3 cells degraded HRP much more slowly than did those of control mice. In controls, HRP was demonstrable in S3 lysosomes at 18 hours but not at 48 hours after injection. In beige mouse kidney HRP was demonstrable in many S3 lysosomes at 48 hours, and it persisted in some lysosomes as long as 5 days after injection. These findings indicate that beige S3 lysosomes are defective in degrading protein. As reported recently, these lysosomes are also markedly enlarged and altered in content. They appear to arise as part of a renal lesion of unknown pathogenesis which is confined to the S3 segments of the proximal tubules. The slower rate of degradation of protein appears to be another manifestation of the alteration in these lysosomes.

Animals↗

Suppression of pigmentation in mouse melanoma cells by 5-bromodeoxyuridine: effects on tyrosinase activity and melanosome formation.

Low concentrations (1-3 microg/ml) of 5-bromodeoxyuridine (BrdU) reversibly suppress pigmentation in a highly pigmented clone (B(5)59) of cultured B16 mouse melanoma cells. We have found that unpigmented cells (clone C(3)471), derived by long-term culture of B(5)59 cells in 1 microg of BrdU/ml, were completely amelanotic with no biochemically or cytochemically detectable tyrosinase activity or ultrastructural evidence of premelanosomes. The process by which pigmentation is suppressed was studied in B(5)59 cells during a 7-day period of growth with BrdU (3 microg/ml). Assays of tyrosinase activity showed that activity was reduced after 1 day and decreased progressively, approaching zero by 7 days. A quantitatively minor part of this reduction was directly attributable to the appearance of a dialyzable inhibitor of tyrosinase activity. Acrylamide gel electrophoresis revealed two bands of activity corresponding in Rx values to the T(1) and T(2) forms of soluble tyrosinase. Both were progressively reduced during growth with BrdU but one form (T(1)) was consistently affected earlier than the other (T(2)). Ultrastructural-cytochemical studies also showed an early effect on the localization of tyrosinase reaction product. At day 3, reaction product was no longer present in Golgi saccules and Golgi-associated smooth surfaced tubules, but was still seen within premelanosomes, compound melanosomes, and occasional Golgi-associated vesicles. By 7 days tyrosinase reaction product was usually not demonstrable. The number of premelanosomes was progressively decreased during growth with BrdU. Premelanosomes became concentrated in the juxtanuclear region and at day 3 many were contained within abnormally large and numerous compound melanosomes. Premelanosomes and compound melanosomes were rarely seen at 7 days, by which time the cultures were nearly amelanotic. The coordinated suppression of melanogenesis by BrdU may provide a useful model in which to study the normal regulation of this process.

Animals↗

A hereditary alteration in kidneys of mice with Chediak-Higashi syndrome.

The beige mouse is considered to be a homologue of Chediak-Higashi syndrome (CHS). Cytochemical and electron microscopic studies have revealed an inherited lesion in the kidneys of these mice. The alteration was confined to the distal segments (S3) of the proximal tubules and was characterized by the accumulation of numerous massive polysaccharide-rich granules. These granules were reactive for acid phosphatase and beta-glucuronidase activities and were therefore considered to be lysosomes. Small numbers of lymphocytes were also observed in the perivascular spaces and within the tubules of the S3 segment. The fine structure of S3 cells was also markedly altered. In addition to the massive lysosomes, dense material was found associated with the brush border and was present in pinocytotic vesicles at the base of the brush border and between basal invaginations of the plasma membranes. Despite these changes, reabsorption of exogeneous peroxidase by S3 cells appeared to be normal. The presence of a congenital defect in the kidney of the beige mouse appears to provide a useful model for studying the morphology and function of the S3 region of the nephron.

Acid Phosphatase↗