Liver parenchymal cell injury. 3. The nature of calcium--associated electron-opaque masses in rat liver mitochondria following poisoning with carbon tetrachloride

Fine structural study of myocardial changes induced by isoproterenol in rhesus monkeys. (Macaca mulatta)

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An electron microscopic study of ferrous sulfate induced liver damage

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Fine structure of normal human juxtaglomerular cells. I. General structure and intercellular relationships

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The intracellular distribution of calcium in the mucosa of the avian shell gland

The intracellular distribution of calcium has been studied in the mucosa of the avian shell gland, a tissue which transports large quantities of calcium during discrete time intervals. Ca(45) was administered to hens either in a single dose followed by sacrifice 5 min later or in repeated doses over an extended period followed by sacrifice 2 hr or 24 hr after the last injection. Subcellular fractions were isolated by differential centrifugation and analyzed for Ca(45). The Ca(45) was located principally in the particulate fractions; the concentration (CPM Ca(45)/mg N) was highest in the mitochondrial fraction. Comparisons of (1) the Ca(45) distribution in shell gland cells with that of liver cells, (2) the alterations which occur due to the phase of the egg laying cycle, (3) the effects due to the time elapsed since the last injection of Ca(45), and (4) the Ca(45) distribution of the short term experiments with that of the long term experiments revealed that the mitochondrial fraction of the shell gland appeared to be active in the movement of calcium. The microsomal fraction showed increased values in CPM Ca(45)/mg N when calcification was occurring, which may indicate that the subcellular components of this fraction have a role in calcium transport. The nuclear and supernatant fractions did not seem to be involved in the transport process. The implications of these results concerning the manner by which calcium may be controlled on a cellular level in this system are discussed.

Effects of starvation on the hepatotoxicity of carbon tetrachloride. A light and electron microscopic study

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Studies on tetanus. IV. Intramitochondrial dense granules in skeletal muscle from human cases of tetanus intoxication

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Electron microscope studies on the active accumulation of Sr++ by rat-liver mitochondria

Electron-opaque granules are deposited in isolated rat-liver mitochondria concomitant with the energy-linked accumulation of Sr(++) by these organelles. High temperature microincineration (600 degrees C) of thin sections of mitochondria containing different amounts of Sr(++) shows that a clear qualitative correlation exists between the number of inorganic residues remaining after incineration and the amount of Sr(++) translocated into the mitochondria. By loading the mitochondria with consecutive pulses of small amounts of Sr(++) ("multiple-pulse" loading), very early stages of granule formation can be detected; the first detectable deposits are seen closely associated with the cristae. The evidence presented supports the hypothesis that mineral deposition following or during the in vitro accumulation of ions by mitochondria occurs, at least initially, at sites on these membranes and not as nonspecific precipitates in the mitochondrial matrix. The large number of electron-opaque deposits (100 to 200) seen in single thin sections of individual mitochondria having accumulated intermediate levels of Sr(++) clearly exceeds the number of normal dense granules in rat-liver mitochondria, indicating that the normal matrix granules per se do not constitute sites essential for deposition. At the highest levels of Sr(++) uptake studied in the multiple-pulse loading experiments, needlelike deposits are seen, a result which suggests that the structural form ("crystallinity") of the mineral deposits may be determined by the rate of accumulation.