Localization of acid phosphatase activity in hepatic lysosomes by means of electron microscopy

An ultrastructural and biochemical study of the effects of three inhibitors of cholesterol biosynthesis upon murine adrenal gland and testis. Histochemical evidence for a lysosome response

Triparanol and 20,25-diazacholesterol inhibit cholesterol biosynthesis and result in the accumulation of desmosterol. AY-9944, another inhibitor, produces an accumulation of 7-dehydrocholesterol. Adult male C3H mice receive one of these drugs intraperitoneally. Livers, adrenal glands, and testes from each drug group are excised, and portions of each are analyzed by a modified Liebermann-Burchard reaction for quantitation of sterols. Adrenals and testes are examined also by electron microscopy. Fine-structural localization of acid phosphatase has been studied in triparanol-treated adrenal glands. Biochemical analysis reveals that 14-64% of the sterols occurs as desmosterol or 7-dehydrocholesterol. Fine-structural alterations in the adrenal glands and testes from each drug group are essentially identical. The predominant cytological feature is the occurrence of increased numbers of pleomorphic, unit-membrane-limited, electron-opaque, cytoplasmic inclusions. Hence, the cellular modifications following triparanol administration are not unique, as has been suggested. They represent a generalized phenomenon, probably related to inhibition of cholesterol biosynthesis, which is an effect common to each drug. Lead phosphate reaction product (indicating acid phosphatase activity) is demonstrable within these membrane-limited cytoplasmic bodies, identifying them as morphological lysosomes. The utilization of a lysosomal mechanism in sterol-synthesizing cells, which are accumulating cholesterol intermediates, is discussed.

Studies on the pathogenesis of hepatolenticular degeneration. 3. The effect of copper on rat liver lysosomes

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The circumfusion system for multipurposeculture chambers. II. The protracted maintenance of differentiation of fetal and newborn mouse liver in vitro

The circumfusion system is a complex in vitro pumping unit incorporating 12 multipurpose culture chambers through which a serum-supplemented fluid nutrient is recirculated at a rate of 4.5 ml/min per chamber. This system was used to study the differentiative responses of fetal and newborn mouse liver explants placed in the serum-free environment formed between the sheets of unperforated cellophane and cover glasses of the chambers. Hepatocytes (parenchymal cells) were discernible in 3-5 days. They retained many of their features of differentiation in the circumfusion system for more than 120 days of cultivation. The living morphological characteristics of the hepatocytes were studied by phase-contrast microscopy (direct viewing and time-lapse cinemicrography) and by special cytochemical staining. Electron micrographs were made of both fresh liver specimens and the cultured cells. Comparisons of the cultured parenchymal cells with their in vivo progenitors showed a remarkable preservation of their differentiated state.

Renal transplantation in the inbred rat. V. Histochemical studies of acute renal allograft rejection

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Combined cytochemical and electron microscopic demonstration of beta-glucuronidase activity in rat liver with the use of a simultaneous coupling azo dye technique

Rat liver was fixed in formal-cacodylate-sucrose and frozen sections were incubated in a simultaneous-coupling medium containing naphthol AS-BI glucuronide as substrate and hexazonium pararosanilin as the diazo reagent. By light microscopy, the sections demonstrated beta-glucuronidase activity as red discrete granules in the pericanalicular cytoplasm and as a generalized cytoplasmic stain in the parenchymal cells. Brief treatment of sections in cold ethanol prior to incubation markedly enhanced the staining for the enzyme and made it possible to demonstrate sufficient amounts of the reaction product in sections embedded in epoxy resin following dehydration and propylene oxide treatment. Electron microscopy revealed that the reaction product was moderately electron opaque and deposited in greater amounts in the vacuolated dense bodies and occasionally in the dense bodies which did not show obvious vacuoles. In each dense body, the deposits occurred preferentially at the edge as well as in the area surrounding the vacuoles in the matrix. Control sections incubated in the presence of glucosaccharo-1:4-lactone were devoid of the reaction product. No deposits of the reaction product were found in the nucleus, mitochondria, or microbodies. The limitations of the present cytochemical technique for use in electron microscopy are briefly discussed.

Localization of acid phosphatase in lipofuscin granules and possible autophagic vacuoles in interstitial cells of the guinea pig testis

The intracellular localization of acid phosphatase in guinea pig testicular interstitial cells was investigated by incubating nonfrozen thick sections of glutaraldehyde-perfused testis in a modified Gomori medium and preparing the tissue for electron microscopy. Lipofuscin pigment granules in these cells contain dense pigment, granular matrix, and often a lipid droplet. Reaction product is seen in the matrix of the pigment granules, and they may therefore be called residual bodies. At least some of the dense pigment appears to be derived from myelin figures and membrane whorls, since suitable intermediates can be seen. Lipid droplets found free in the cytoplasm are another possible source of pigment. In both cases the chemical mechanism is presumed to be autoxidation of unsaturated lipid. Acid phosphatase is present in the inner cisterna of Golgi elements. Enzyme activity also appears in possible autophagic vacuoles bounded by double membranes; the reaction product lies between the membranes. Consideration of the enzyme as a tracer suggests that the autophagic vacuoles are derived from the Golgi complex. Possible stages in the formation of these vacuoles by the inner Golgi cisternae are observed.

Histochemistry of lysosomal enzymes in developing teeth of albino rats

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Ultrathin frozen sections. II. Demonstration of enzymic activity

Endogenous enzyme activity can be readily and routinely demonstrated in ultrathin, frozen sections for electron microscopy. The procedure employed to obtain the best structural preservation as well as enzyme activity in thin sections involved fixation in glutaraldehyde, embedding in thiolated gelatin or pure gelatin, partial dehydration in glycerol, and sectioning in a cryostat at -35 degrees C with a slightly modified Porter-Blum microtome on which the tissue is maintained at -70 degrees C and the knife at -23 degrees C. Kidney cortex was used as test tissue, but a few other organs were occasionally used. Thin sections were floated on the surface of several incubation media routinely employed for enzyme cytochemistry. Positive, specific reactions were obtained for alkaline phosphatase in kidney brush border, for adenosine triphosphatase in brush border and in basal membranes of distal tubules, for acid phosphatase and esterase in lysosomes, and for NADH diaphorase in mitochondria. Mitochondrial ATPase was sporadically evident only in the distal tubule of the kidney. Localizations of enzyme activity reported by other technical approaches were confirmed and in some cases somewhat improved.

Enzyme-labeled antibodies for the light and electron microscopic localization of tissue antigens

Enzymes, either acid phosphatase or horseradish peroxidase, were conjugated to antibodies with bifunctional reagents. The conjugates, enzymatically and immunologically active, were employed in the immunohistochemical localization of tissue antigens utilizing the reaction product of the enzymatic reaction as the marker. Tissues reacted with acid phosphatase-labeled antibodies directed against basement membrane were stained for the enzyme with Gomori's method, and those reacted with peroxidase-labeled antibody were stained with Karnovsky's method. The reaction products of the enzymes localized in the basement membrane. Unlike the preparations of the fluorescent antibody technique, enzyme-labeled antibody preparations were permanent, could be observed with an ordinary microscope, and could be examined with the electron microscope. In the latter, specific localization of antibody occurred in the basement membrane and in the endoplasmic reticulum of cells known to synthesize basement membrane antigens. The method is sensitive because of the amplifying effect of the enzymatic activity. The ultrastructural preservation and localization were better with acid phosphatase-labeled antibody than with peroxidase-labeled antibody, but acid phosphatase conjugated antibody was unstable and difficult to prepare. Peroxidase-antibody conjugates were stable and could be stored for several months at 4 degrees C, or indefiniely in a frozen state.

The fine structure of the astroglia in the human optic nerve and optic nerve head

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Ferritin in synovial cells in patients with rheumatoid arthritis

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The nucleoids of rat liver cell microbodies. Fine structure and enzymes

The nucleoids of microbodies of rat liver cells were isolated in a highly homogeneous and pure state, by treating the microbody-rich fraction, prepared from 10% polyvinylpyrrolidone-0.25 M sucrose homogenate, with Triton X-100. Three treatments with 0.1% detergent were enough to render the nucleoids free from contamination with mitochondria, microsomes, lysosomes, and intact microbodies. Electron microscopically, the nucleoids were found to consist of parallel bundles of highly dense hollow tubules, the outer and inner diameters of which are approximately 150 and 50 A, respectively. Ten tubules are arranged around a longitudinal space 190 x 200 A in width. The nucleoids thus show a honeycomb appearance in the cross-plane and a parallel-packed structure in the longitudinal plane. Biochemically, the nucleoids were found to bear only urate oxidase among probably microbody-enzymes, and they might be the only cytoplasmic particles of rat liver cells in which the enzyme locates. Urate oxidase activity, on a unit protein basis, of the nucleoid preparation is approximately 380 times as high as that of the whole homogenate, and is almost comparable with that of a commercial type I enzyme preparation. No enzymes of mitochondrial, microsomal, and lysosomal origins were detected in the nucleoids. The fine structure of the nucleoids is described in detail, and a probable schematic diagram is presented.

Lysosomes: some pathologic implications

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