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Biomedical subjects

H Goldenberg

Publications and source records attributed to H Goldenberg.

At least 73 records · Page 4Linked to original sources
PubMed1980

[Complexed microsomal antigens in acute hepatitis B (author's transl)].

Microsomal antigens and corresponding antibodies are predominantly detected following halothane hepatitis and chronic active hepatitis with autoimmune markers. In the case of acute hepatitis B reported by us, complexed microsomal antigens were found during active disease, gradually clearing with seroconversion of microsomal markers and improvement of liver function.

Adult↗
PubMed1979

A characteristic membrane protein of liver peroxisomes inducible by clofibrate.

In sodium dodecyl sulfate polyacrylamide electrophoresis the membranes of rat liver peroxisomes show nine main protein bands (40 000--100 000 dalton); the 40 000-dalton polypeptide cannot be resolved from the membrane by deoxycholate. Treatment of the rats with clofibrate largely increases this protein and another one (about 80 000 dalton) in the peroxisomal but not in the endoplasmic reticulum membrane. Proliferation of peroxisomes seems to be connected with the insertion of specific proteins into the membrane.

Animals↗
PubMed1979

Distribution of insulin receptors among mouse liver endomembranes.

Specific binding of insulin to highly purified preparations of rough endoplasmic reticulum, Golgi apparatus, and plasma membrane of mouse liver was determined. 125I-labeled insulin bound maximally to the plasma membrane in radio-receptor assays. Golgi apparatus fractions exhibited binding 10--20% that of plasma membrane and rough endoplasmic reticulum exhibited only 1--2% of plasma membrane binding. Binding was proportional to membrane concentration and dose vs. response curves were very similar for the different fractions. Scatchard analysis of the insulin binding data for the plasma membrane and Golgi apparatus fractions showed curvilinear plots yielding similar apparent binding affinities (0.9 and 3.0-10(8) M-1, respectively). Purity of the isolated endomembranes was analyzed by morphometry and (Na+ + K+ + Mg2+)-ATPase and these preparations displayed less than 1% contamination by plasma membrane. These findings provide important confirmation of the presence of insulin receptors in Golgi apparatus membranes comparable to those located on the plasma membrane. Finally, the present study did not allow us to verify the existence of insulin receptors in the endoplasmic reticulum.

Animals↗
PubMed1978

Beta-oxidation in peroxisomes of brown adipose tissue.

Peroxisomes and mitochondria from brown adipose tissue of the rat were separated by differential pelleting and isopycnic gradient centrifugation. Both fractions oxidized palmitoyl-CoA with comparable specific activities. Unlike the mitochondrial beta-oxidation the peroxisomal activity was not influenced by carbon monoxide. Peroxisomal beta-oxidation together with carnitine acetyl-transferase, which is also located in peroxisomes, might be involved in chemical thermogenesis by delivering acetyl groups to the mitochondria.

Adipose Tissue, Brown↗
PubMed1978

Catalase positive particles from pig lung. Biochemical preparations and morphological studies.

In pig lung tissue catalase positive particles (CPs) are abundant especially in type II pneumocytes and in Clara cells. In both cell types they occur as circular, oval or elongated membrane profiles surrounding a moderately electron dense matrix lacking a crystalline core. In Clara cells and in part of type II pneumocytes they are located as individual particles without any evident morphological relation to other cell organelles. In part of type II pneumocytes 5-8 particles are forming a group and their close relation to agranular endoplasmic reticulum cisterns is evident. The particles can be purified from lung homogenates by fractionated pelleting and subsequent rate sedimentation in a sucrose gradient using a zonal rotor. The catalase rich fraction bands in the middle of the gradient whereas cytochrome oxidase and part of the acid phosphatase sediments at its heavy end. A second part of acid phosphatase stays at the light end of the gradient and--according to morphological control--seems to correspond to lamellar bodies of the type II pneumocytes. The purified catalase positive particles do not contain hydroxyacid and D-aminoacid oxidases thought to be characteristic H2O2 producing enzymes of peroxisomal systems. The buoyant density of the particles (d = 1.195 g/cm3) is lower than that of liver peroxisomes. Cytochemical controls of the peroxisomal pellets exhibit the particles partly uniformly filled with reaction product, partly irregularly stained.

Acid Phosphatase↗
PubMed1978

Preparation of peroxisomes from carp liver by zonal rotor density gradient centrifugation.

Peroxisomes from carp liver can be separated by isopycnic density gradient centrifugation in sucrose. Without reaching complete sedimentation equilibrium, the purification by this method is quite successful. There is a 40-fold enrichment of catalase, the peroxisomal marker, with a total yield of 27%. No pretreatment of animals is necessary for separation from lysosomes, which, besides high fragility, show lower buoyant densities than peroxisomes. The enzyme content of carp liver peroxisomes is similar to that of rat liver, with the exception of alpha-glycerophosphate dehydrogenase, which in this tissue is a completely soluble cytoplasmic enzyme. Total activities are much lower than in the rat, for the characteristic peroxisomal oxidases the difference being in the range of one order of magnitude.

Alcohol Oxidoreductases↗
PubMed1978

Cytochemical demonstration of glutaraldehyde-resistant NADH-ferricyanide oxido-reductase activities in rat-liver plasma membranes and Golgi apparatus.

NADH-ferricyanide reductase activity was demonstrated in rat liver endomembranes by cytochemical procedures. The activity observed in plasma membrane and mature portions of the Golgi apparatus resisted fixation in 0.1% glutaraldehyde, a characteristic which permitted differentiation of the NADH-ferricyanide reductase of plasma membranes and mature Golgi apparatus elements from those of mitochondria, microbodies, endoplasmic reticulum and nuclear envelope. With the latter membranes, activity could be demonstrated only with unfixed material or following brief glutaraldehyde fixation and was greatest with broken cells or isolated fractions due to problems of penetration of reagents. Biochemical studies paralleled cytochemical findings with respect to glutaraldehyde fixation and sensitivity to other metabolic inhibitors. The findings provide evidence that a NADH-ferricyanide reductase may be among the membrane constituents conserved and/or modified during flow differentiation of membranes. The basis for a method to evaluate plasma membrane contamination of endoplasmic reticulum fractions and to differentiate among mature and immature secretory vesicles of the Golgi apparatus is also indicated.

Animals↗
PubMed1977

Organization of purpine degradation in the liver of a teleost (carp; Cyprinus carpio L.). A study of its subcellular distribution.

Carp liver was fractionated by differential and density gradient centrifugation and assayed for enzymes of purine catabolism. While urate oxidase is an exclusively peroxisomal enzyme, only a very small percentage of the enzymes xanthine oxidase, allantoinase and allantoicase is associated with subcellular or ganelle fractions. There is no general purine catabolizing subcellular compartment. There is some but not yet conclusive evidence for the assumption that urate oxidase is a membrane bound enzyme.

Acid Phosphatase↗
PubMed1976

Enzymic and morphological studies on catalase positive particles from brown fat of cold adapted rats.

Brown adipose tissue of normal and cold-adapted adult rats has been investigated morphologically and cytochemically. In thin-sections catalase-positive particles appear as circular, oval or elongated profiles lying either as single particles or forming groups. Biochemical studies on peroxisomal enzymes show an increase of catalase activity to the tenfold amount after cold adaptation. The tissue is devoid of D-aminoacid oxidase and glycolate oxidase, while low activities of middle-chain-alpha-hydroxyacid oxidases could be detected. The catalase-positive particles were purified by differential and is lower than that of the liver peroxisomes. Enzymic investigations of the fractions render it probably that particles contain carnitine acetyltransferase, whereas they are lacking NAD-dependent glycerophosphate dehydrogenase. The pellets derived from the gradient centrifugation have been checked morphologically for purity. After performing DAB-cytochemistry for identification of the peroxidatic activity of catalase, most of the particles were shown to be structurally intact and homogeneously filled with reaction product.

Adipose Tissue, Brown↗
PubMed1976

Effect of clofibrate application on morphology and enzyme content of liver peroxisomes.

Male albino rats (Sprague Dawley) were fed for 2-6 weeks on a diet containing 0.75% clofibrate. Liver cell fractions obtained from these animals were assayed for peroxisomal enzymes. In the cell homogenate the catalase activity was doubled, whereas the activity of urate oxidase was found to be only slightly depressed. The activity of carnitine acetyltransferase increased several times. In liver peroxisomes purified by isopycnic gradient centrifugation the specific activity of urate oxidase decreased appreciably showing that peroxisomes formed under the proliferative influence of clofibrate are not only modified with respect to their morphological characteristics but also to their enzymic equipment. This is also obvious from the changes in peroxisomal carnitine acetyltransferase activity which was enhanced by clofibrate to more than the fivefold amount. In purified mitochondria this enzyme was even more active: clofibrate advances both, the peroxisomal and the mitochondrial moiety of carnitine acetyltransferase. Morphological and cytochemical studies showed an increase in the number of microbodies and as compared to the controls microbodies were lying in groups more frequently. Small particles located closely adjacent to "normal" sized peroxisomes were found particularly after short feeding periods. While the number of coreless microbodies increased studies gave no clear evidence for an increase in marked shape irregularities of the peroxisomes.

Animals↗
PubMed1975

Influence of subtotal hepatectomy on peroxisomes and peroxisomal enzymes of rat liver and isolated liver cell fractions.

The activities of peroxisomal enzymes of rat liver were followed 1 to 10 days after subtotal (60-70%) hepatectomy in homogenates prepared from regenerating livers and in cell fractions isolated from them. Catalase activity was found to be depressed in the total liver homogenate (H) as well as in the mitochondrial (M) and soluble (S) fractions, while it did not change appreciably in the microsomal (Mc) and lysosomal (L) fractions. Alpha-hydroxyacid oxidase behaved in a similar fashion. In contrast to these enzymes, urate oxidase activity remained unchanged in H, whereas it was decreased in M and increased in L and Mc during the first 5 days after operation. These results agree well with the assumption that microbody proliferation is initiated by the fragmentation of large peroxisomes. The different relations of peroxisomal enzyme activities during regeneration time are discussed with respect to the possible existence of various kinds of peroxisomes with different enzyme equipments and with different turnover rates. Biochemical examinations ions were paralleled to morphological and histochemical studies. An early increase in number of peroxisomes was found to occur during the first day after partial hepatectomy, which is accompanied by decrease in particle size. During the first mitotic wave (24-36 hrs post op.) the number of peroxisomes per cell was reduced to about the half. After this time number and size of the particles began to increase. Positive staining of ribosomes was frequently observed in the vicinity of peroxisomes after the application of the cytochemical catalase reaction (alkaline diaminobenzidine medium). This phenomenon is interpreted to represent rather a diffusion artifact than the cytochemical identification of newly synthesized catalase.

Alcohol Oxidoreductases↗