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Determination of Threshold Dose of Photodynamic Therapy to Measure Superficial Necrosis

FERRAZ, R. C. M. C.; FERREIRA, J.; MENEZES, P. F. C.; SIBATA, C. H.; SILVA JR., O. Castro e; BAGNATO, V. S.
Fonte: MARY ANN LIEBERT INC Publicador: MARY ANN LIEBERT INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.482563%
Background Data: Photodynamic therapy (PDT) involves the photoinduction of cytotoxicity using a photosensitizer agent, a light source of the proper wavelength, and the presence of molecular oxygen. A model for tissue response to PDT based on the photodynamic threshold dose (Dth) has been widely used. In this model cells exposed to doses below Dth survive while at doses above the Dth necrosis takes place. Objective: This study evaluated the light Dth values by using two different methods of determination. One model concerns the depth of necrosis and the other the width of superficial necrosis. Materials and Methods: Using normal rat liver we investigated the depth and width of necrosis induced by PDT when a laser with a gaussian intensity profile is used. Different light doses, photosensitizers (Photogem, Photofrin, Photosan, Foscan, Photodithazine, and Radachlorin), and concentrations were employed. Each experiment was performed on five animals and the average and standard deviations were calculated. Results: A simple depth and width of necrosis model analysis allows us to determine the threshold dose by measuring both depth and surface data. Comparison shows that both measurements provide the same value within the degree of experimental error. Conclusion: This work demonstrates that by knowing the extent of the superficial necrotic area of a target tissue irradiated by a gaussian light beam...

Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome

VOLLET-FILHO, Jose Dirceu; CARACANHAS, Monica Andrioli; GRECCO, Clovis; FERREIRA, Juliana; KURACHI, Cristina; BAGNATO, Vanderlei Salvador
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.59062%
Background: Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem(R), in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. Methods: Fifteen male Wistar rats were intravenously photosensitized with 1.5 mg/kg body weight of Photogem(R). Laser-induced fluorescence spectroscopy at 532nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. Results: Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. Conclusions: As a consequence of these results...

Comparison of polysomal and nuclear poly(A)-containing RNA populations from normal rat liver and Novikoff hepatoma.

Capetanaki, Y G; Alonso, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/07/1980 EN
Relevância na Pesquisa
67.85253%
Polysomal and nuclear poly(A)-containing RNA of normal rat liver and Novikoff hepatoma cells have been compared by cDNA.RNA hybridization kinetics. Homologous hybridization reactions revealed at total kinetic complexity of about 1.6 X 10(10) and 1.38 X 10(10) daltons for liver and Novikoff mRNA respectively. The high abundance component present in liver cannot be detected in Novikoff. It was found from heterologous reactions that about 30% by weight of mRNA sequences are specific to liver. Determination of the nuclear poly(A)-containing RNA complexities revealed that about 5.5% and 4% of the haploid genome is expressed in the liver and Novikoff respectively. In a heterologous reaction, up to 30% of the liver cDNA failed to form hybrids with Novikoff nuclear RNA. Cross hybridizations have further revealed abundance shifts in both nuclear and polysomal RNA populations. Some sequences abundant in liver are less abundant in Novikoff and some rare liver sequences are relatively abundant in Novikoff.

Changes in nuclear and polysomal polyadenylated RNA sequences during rat-liver regeneration.

Wilkes, P R; Birnie, G D; Paul, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1979 EN
Relevância na Pesquisa
58.341313%
Nuclear and polysomal polyadenylated RNA populations of normal and 16 hour regenerating rat liver have been compared by mRNA-cDNA hybridisations and by unique DNA saturation experiments. It was found that nuclear polyadenylated RNA hybridises to 6.8% of unique DNA in both normal and 16 hour regenerating rat liver. However, cross-hybridisation experiments using cDNA have shown that 10-15% by weight of nuclear polyadenylated RNA sequences are specific to 16 hour regenerating rat-liver. Since both unique DNA and cDNA hybridisation have shown that normal and 16 hour regenerating rat-liver polysomal polyadenylated RNA populations are qualitatively very similar sequences specific to 16 hour regenerating rat-liver nuclear polyadenylated RNA are nucleus confined. Polysomal RNA sequences which were abundant in normal rat-liver have become less abundant in regenerating rat liver.

Lipocytes from normal rat liver release a neutral metalloproteinase that degrades basement membrane (type IV) collagen.

Arthur, M J; Friedman, S L; Roll, F J; Bissell, D M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1989 EN
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67.61092%
We report a proteinase that degrades basement-membrane (type IV) collagen and is produced by the liver. Its cellular source is lipocytes (fat-storing or Ito cells). Lipocytes were isolated from normal rat liver and established in primary culture. The cells synthesize and secrete a neutral proteinase, which by gelatin-substrate gel electrophoresis and gel filtration chromatography, has a molecular mass of 65,000 D. The enzyme is secreted in latent form and is activated by p-aminophenylmercuric acetate but not by trypsin. Enzyme activity in the presence of EDTA is restored selectively by zinc and is unaffected by serine-protease inhibitors. In assays with radiolabeled soluble substrates, it degrades native type IV (basement membrane) collagen but not interstitial collagen types I or V and exhibits no activity against laminin or casein. At temperatures causing partial denaturation of soluble collagen in vitro, it rapidly degrades types I and V. Thus, it is both a type IV collagenase and gelatinase. The enzyme may play a role in initiating breakdown of the subendothelial matrix in the Disse space as well as augmenting the effects of collagenases that attack native interstitial collagen.

Degradation of endogenous hepatic heme by pathways not yielding carbon monoxide. Studies in normal rat liver and in primary hepatocyte culture.

Bissell, D M; Guzelian, P S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1980 EN
Relevância na Pesquisa
67.689907%
The conversion of endogenous hepatic heme to bilirubin and CO is established. However, it is unknown whether this process is quantitative or whether heme may be degraded to other products as well. To study this question, we administered the heme precursor, delta-amino-[5-14C]levulinic acid to rats in vivo. In liver, [14C]heme was predominately associated with microsomal cytochromes, and its degradation was examined over a period of 12--14 h; concurrently, excretion of labeled carbon monoxide 14CO by the animal was measured. After correction for 14CO derived from the breakdown of renal [14C]heme, the rate of heme degradation calculated from the 14CO excreted was substantially less than the rate of disappearance of hepatic [14C]heme measured directly. The discrepancy between actual loss of labeled heme from the liver and generation of labeled CO was confirmed by direct study of endogenous [14C]heme degradation in primary hepatocyte culture, in which only 25% of the labeled heme disappearing during the incubation was converted to 14CO. By contrast, cultured cells converted exogenous [14C]heme nearly quantitatively to 14CO. We conclude that heme associated with microsomal cytochromes in normal rat liver is degraded substantially by non-CO forming processes.

Hepatic lipocytes: the principal collagen-producing cells of normal rat liver.

Friedman, S L; Roll, F J; Boyles, J; Bissell, D M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1985 EN
Relevância na Pesquisa
67.84369%
Hepatic lipocytes were isolated from normal rat liver and established in culture. A virtually pure isolate was obtained by fractionating enzymatically digested liver on a discontinuous gradient of arabinogalactan. Isolated cells displayed prominent rough endoplasmic reticulum and typical cytoplasmic droplets containing vitamin A. Lipocytes in primary culture were shown by immunofluorescence to secrete collagen types I, III, and IV and also laminin. Immunoassay of culture media showed that lipocytes during the first week in culture secrete type I (72.1-86.2% of total measured soluble collagen), type III (2.6-7.2%), and type IV (11.2-29.7%) collagens. Five percent of total secreted protein was collagen compared with 0.2% in similarly cultured hepatocytes and 1.7% in sinusoidal endothelial cells, as measured by the production of peptide-bound [3H]hydroxyproline in cells incubated with [3H]proline. The calculated amount of collagen synthesized by lipocytes per microgram of cellular DNA was 10-fold greater than that produced by hepatocytes and over 20-fold greater than that produced by endothelial cells. The findings indicate that collagen synthesis and secretion are specialized functions of hepatic lipocytes, and that, in cells from normal liver...

3-Hydroxy-3-methylglutaryl-coenzyme A reductase is present in peroxisomes in normal rat liver cells.

Keller, G A; Barton, M C; Shapiro, D J; Singer, S J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1985 EN
Relevância na Pesquisa
67.736934%
The location inside rat liver parenchymal cells of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase; EC 1.1.1.34), the key regulatory enzyme in cholesterol biosynthesis, has been examined by immunoelectron microscopy and by subcellular fractionation. Although HMG-CoA reductase is generally thought to be exclusively a microsomal enzyme, we find that a substantial portion of cellular HMG-CoA reductase is localized in peroxisomes. Immunoelectron microscopic labeling of ultrathin frozen sections of normal rat liver, using two monoclonal antibodies to purified HMG-CoA reductase, showed that the enzyme is present in the peroxisomes at a higher concentration than at any other site inside the hepatocytes. Subcellular fractionation studies using Percoll and metrizamide gradients demonstrated a close correspondence of peaks of HMG-CoA reductase activity and of catalase activity, again revealing the presence of the reductase enzyme in peroxisomes. HMG-CoA reductase is therefore localized in peroxisomes in addition to being in the microsomal fraction.

Support of cultured hepatocytes by a laminin-rich gel. Evidence for a functionally significant subendothelial matrix in normal rat liver.

Bissell, D M; Arenson, D M; Maher, J J; Roll, F J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1987 EN
Relevância na Pesquisa
67.708857%
The subendothelial space of normal rat liver contains the constituent proteins of a basal lamina, as judged by immunohistochemical study of tissue sections. However, it is unknown whether these proteins constitute a complex with effects on hepatocellular function. We have examined this question, using normal rat hepatocytes cultured on substrata of matrix proteins as a model of the interaction between cells and basal lamina in vivo. In cultures on a type I collagen substratum, albumin secretion decreased progressively after 2 d. By contrast, when cells were cultured on a laminin-rich gel matrix, albumin secretion was stable for at least 3 wk; other functions and ultrastructural morphology were similarly maintained. None of the individual matrix proteins effectively substituted for the gel matrix, suggesting that full support of hepatocellular function requires a complex of matrix proteins. We speculate that a cause of hepatocellular dysfunction in acute inflammation is disruption of this matrix and alteration of its interaction with the hepatocyte plasma membrane.

Comparison of Nucleolar Proteins of Normal Rat Liver and Novikoff Hepatoma Ascites Cells by Two-Dimensional Polyacrylamide Gel Electrophoresis

Orrick, Larry R.; Olson, Mark O. J.; Busch, Harris
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1973 EN
Relevância na Pesquisa
67.851895%
A two-dimensional polyacrylamide gel electrophoresis technique is presented for separation of acid-extracted proteins of isolated nucleoli of normal rat liver and Novikoff hepatoma ascites cells. About 100 distinct protein spots were resolved. Comparison of the patterns for normal liver and Novikoff hepatoma revealed nine spots with markedly different intensities in the two patterns. Two spots were found that were unique to the normal liver pattern, and one spot was found that was unique to the hepatoma pattern.

A direct effect of growth hormone on the incorporation of precursors into proteins and nucleic acids of perfused rat liver

Jefferson, L. S.; Korner, A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1967 EN
Relevância na Pesquisa
58.383115%
1. The livers of rats were perfused in situ. When the amino acid concentration in the perfusing medium was that present in rat plasma, the addition of growth hormone to the medium stimulated the incorporation of labelled amino acids into liver protein only marginally and not to a statistically significant extent. When, however, the amino acid concentration was raised to three times that present in rat plasma, growth hormone significantly and substantially stimulated amino acid incorporation into protein within 30min. of perfusion of normal rat liver. 2. A significant effect of growth hormone on labelling of normal rat-liver protein was seen with concentrations not much greater than those reported to be present in rat plasma. 3. The labelling of nucleic acids of normal and hypophysectomized rat liver by [3H]orotic acid was enhanced by addition of growth hormone to the perfusing medium when normal concentrations of amino acids were used. 4. At elevated concentrations of amino acids, growth hormone stimulated labelling of nucleic acids of hypophysectomized rat liver at 30 and 60min. of perfusion. Under these conditions, nucleic acids of normal rats were labelled to about the same extent in control and hormone-treated livers at 30min. and...

Failure to obtain an autoimmune response following cryosurgery to the normal rat liver.

Townell, N H; Tsantoulas, D; Holborow, E J; Hobbs, K E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1980 EN
Relevância na Pesquisa
67.84369%
Smooth muscle antibody (SMA) and anti-liver-specific lipoprotein (anti-LSP) responses were investigated following five different freeze thaw regimes to the normal rat liver. The livers were examined histologically for evidence of autoimmune liver disease. No SMA or anti-LSP was found in any animal and on histological examination the unfrozen part of all livers was normal. It is concluded that cryosurgical damage to the liver is unlikely to provoke an autoimmune response.

Isolation of Arginine Acceptor-Proteins from Normal Rat Liver and Novikoff Hepatoma Supernatant*

Pinard, J.; de Lamirande, G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1973 EN
Relevância na Pesquisa
68.099795%
In the present report a procedure for the isolation of more specific arginine receptors from the soluble fraction of rat liver and Novikoff hepatoma is described. In normal rat liver the specific activity of these receptors from the soluble fraction of rat liver and Novikoff hepatoma is described. In normal rat liver the specific activity of these receptors is fifteen times greater than that of the other proteins whereas in the Novikoff it is only three to four times higher. Attempts to sub-fractionate this class of acceptors would seem to indicate a relative homogeneity.

A QUANTITATIVE STEREOLOGICAL DESCRIPTION OF THE ULTRASTRUCTURE OF NORMAL RAT LIVER PARENCHYMAL CELLS

Loud, Alden V.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/04/1968 EN
Relevância na Pesquisa
67.837217%
The principles of stereology have been applied to a morphometric analysis of parenchymal cells from the peripheral, midzonal, and central regions of normal rat liver lobules. The fractional volumes of cytoplasm occupied by mitochondria, peroxisomes, lysosomes, lipid, and glycogen have been determined. The surface densities of smooth- and rough-surfaced endoplasmic reticulum and of mitochondrial envelope and cristae have also been measured. The average number and dimensions of mitochondria and peroxisomes have been evaluated. By the use of an independent measurement of the average cytoplasmic volume, these data have been expressed as the actual volumes, areas, and numbers per cell in the different parts of the hepatic lobule. Similarly, the volumes of the envelope, cristae, and matrix compartments and the area of cristae membranes have been calculated for the average-sized mitochondrion in each lobular zone. Structural homogeneity is found in over 80% of normal rat liver parenchymal cells, with most of the significant differences being confined to those cells immediately surrounding the central veins.

Reactivity of monoclonal antibodies to oncoproteins with normal rat liver, carcinogen-induced tumours, and premalignant liver lesions.

Embleton, M. J.; Butler, P. C.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em /01/1988 EN
Relevância na Pesquisa
68.070063%
Monoclonal antibodies to proteins encoded by the ras, myb, myc, erb-B, src and PDGF-2 genes were tested for reactivity with normal rat liver, livers from rats fed with 0.06% 2-acetylaminofluorene (AAF), and premalignant lesions and primary liver tumours from rats given AAF alone or a combined treatment with diethylnitrosamine and AAF. Radioimmunoassays were performed with plasma membrane fractions and total soluble subcellular extracts of the tissues, and immunoperoxidase staining was carried out on frozen tissue sections. All of the antibodies were positive in radioimmunoassays, some more strongly than others, and each antibody bound equally to extracts of different kinds of tissue. Immunohistology revealed significant staining of normal liver by 5 of the 6 antibodies, and only minor qualitative differences of the staining pattern in some tumours and hyperplastic nodules. It was concluded that these antibodies were not able to discriminate sufficiently well between normal, premalignant and malignant rat liver to be of value in identifying the precursor cells of malignant tumours.

Expression of ECM proteins fibulin-1 and -2 in acute and chronic liver disease and in cultured rat liver cells

Piscaglia, Fabio; Dudás, József; Knittel, Thomas; Di Rocco, Paola; Kobold, Dominik; Saile, Bernhard; Zocco, Maria Assunta; Timpl, Rupert; Ramadori, Giuliano
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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58.344365%
Fibulin-2 has previously been considered as a marker to distinguish rat liver myofibroblasts from hepatic stellate cells. The function of other fibulins in acute or chronic liver damage has not yet been investigated. The aim of this study has been to evaluate the expression of fibulin-1 and -2 in models of rat liver injury and in human liver cirrhosis. Their cellular sources have also been investigated. In normal rat liver, fibulin-1 and -2 were both mainly present in the portal field. Fibulin-1-coding transcripts were detected in total RNA of normal rat liver, whereas fibulin-2 mRNA was only detected by sensitive, real-time quantitative polymerase chain reaction. In acute liver injury, the expression of fibulin-1 was significantly increased (17.23-fold after 48 h), whereas that of fibulin-2 was not modified. The expression of both fibulin-1 and -2 was increased in experimental rat liver cirrhosis (19.16- and 26.47-fold, respectively). At the cellular level, fibulin-1 was detectable in hepatocytes, “activated” hepatic stellate cells, and liver myofibroblasts (2.71-, 122.65-, and 469.48-fold over the expression in normal rat liver), whereas fibulin-2 was restricted to liver myofibroblasts and was regulated by transforming growth factor beta-1 (TGF-β1) in 2-day-old hepatocyte cultures and in liver myofibroblasts. Thus...

Estrogen Binding Protein Activity in Morris Hepatoma 7777 Compared With Normal Rat Liver

FRANCAVILLA, A.; EAGON, P. K.; DILEO, A.; VAN THIEL, D. H.; OVE, P.; WU, S. K.; SAX, S. A.; STARZL, T. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1984 EN
Relevância na Pesquisa
68.10897%
Estrogen binding protein activities were determined in the cytosol from adult male Buffalo rat liver and Morris hepatoma 7777. Estrogen receptors were prepared using the protamine sulfate precipitation technique of Chamness. The ability of various unlabeled steroids competing with [3H]estradiol was examined to establish the binding specificity. Estradiol binding in Morris hepatoma 7777 cytosol was greatly decreased compared with that present in hepatic cytosol prepared from normal rat liver. The receptor concentration expressed as femtomoles per milligram of cytoplasmic protein was 31.1 ± 2.9 SD for normal rat liver and 0.41 ± 0.88 SD for the hepatoma. Gel filtration chromatography revealed the presence of an estrogen binder in hepatoma cytosol which was not present in either normal liver or in the protamine sulfate precipitates of hepatoma cytosol. The molecular weight, binding specificity, and precipitation of this protein by specific antiserum suggests that it is α-fetoprotein.

Coexpression of ecto-5′-nucleotidase/CD73 with specific NTPDases differentially regulates adenosine formation in the rat liver

Fausther, Michel; Lecka, Joanna; Soliman, Elwy; Kauffenstein, Gilles; Pelletier, Julie; Sheung, Nina; Dranoff, Jonathan A.; Sévigny, Jean
Fonte: American Physiological Society Publicador: American Physiological Society
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
67.814487%
Ectonucleotidases modulate purinergic signaling by hydrolyzing ATP to adenosine. Here we characterized the impact of the cellular distribution of hepatic ectonucleotidases, namely nucleoside triphosphate diphosphohydrolase (NTPDase)1/CD39, NTPDase2/CD39L1, NTPDase8, and ecto-5′-nucleotidase/CD73, and of their specific biochemical properties, on the levels of P1 and P2 receptor agonists, with an emphasis on adenosine-producing CD73. Immunostaining and enzyme histochemistry showed that the distribution of CD73 (protein and AMPase activity) overlaps partially with those of NTPDase1, -2, and -8 (protein levels and ATPase and ADPase activities) in normal rat liver. CD73 is expressed in fibroblastic cells located underneath vascular endothelial cells and smooth muscle cells, which both express NTPDase1, in portal spaces in a distinct fibroblast population next to NTPDase2-positive portal fibroblasts, and in bile canaliculi, together with NTPDase8. In fibrotic rat livers, CD73 protein expression and activity are redistributed but still overlap with the NTPDases mentioned. The ability of the observed combinations of ectonucleotidases to generate adenosine over time was evaluated by reverse-phase HPLC with the recombinant rat enzymes at high “inflammatory” (500 μM) and low “physiological” (1 μM) ATP concentrations. Overall...

Electrochemical lesions in the rat liver support its potential for treatment of liver tumors

Wemyss-Holden, S.; Robertson, G.; Dennison, A.; de la M Hall, P.; Fothergill, J.; Jones, B.; Maddern, G.
Fonte: Academic Press Inc Elsevier Science Publicador: Academic Press Inc Elsevier Science
Tipo: Artigo de Revista Científica
Publicado em //2000 EN
Relevância na Pesquisa
67.867627%
BACKGROUND: An effective therapy is needed for patients with surgically unresectable liver tumors who have very limited life expectancy. One possible treatment is electrochemical tumor necrosis. This study investigated the natural history of electrochemical lesions in the normal rat liver. MATERIALS AND METHODS: A direct current generator, connected to platinum electrodes, was used to create controlled areas of liver necrosis. Animals were sacrificed 2 days, 2 weeks, 2 months, and 6 months after treatment and the macroscopic and histological appearance of the necrotic lesions was followed. RESULTS: No animal died as a result of electrolysis; postoperatively, all gained weight normally. Liver enzymes were significantly (P < 0.001) elevated after treatment, but returned to normal after a week. Two days after electrolysis, histology confirmed an ellipsoidal area of coagulative necrosis at the site of the electrode tip and commonly a segment of peripheral necrosis. After 2 weeks there was histological evidence of healing. By 6 months, very little necrotic tissue remained within a small fibrous scar. CONCLUSIONS: Electrolysis is a safe method for creating defined areas of liver necrosis that heal well with no associated mortality. This study supports the potential of electrolysis for treating patients with unresectable liver tumors.; Wemyss-Holden...

Presence of albumin mRNA precursors in nuclei of analbuminemic rat liver lacking cytoplasmic albumin mRNA.

Esumi, H; Takahashi, Y; Sekiya, T; Sato, S; Nagase, S; Sugimura, T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1982 EN
Relevância na Pesquisa
58.383115%
Analbuminemic rats, which lack serum albumin, were previously found to have no albumin mRNA in the cytoplasm of the liver. In the present study, the existence of nuclear albumin mRNA precursors in the liver of analbuminemic rats was examined by RNA X cDNA hybridization kinetics. Albumin mRNA precursors were present in the nuclei of analbuminemic rat liver at almost normal levels, despite the absence of albumin mRNA from the cytoplasm. Nuclear RNA of analbuminemic rat liver was subjected to electrophoresis on 1% agarose gel in parallel with nuclear RNA of normal rat liver. RNA was transferred from the gel to diazobenzyloxymethyl-paper and hybridized to cloned cDNA. Several bands of putative albumin mRNA precursors were obtained with nuclear RNA of analbuminemic rat liver and some of them were indistinguishable from those of normal rat liver. Nuclear RNA of analbuminemic rats was hybridized to 3'-end-labeled cloned cDNA under the conditions of RNA excess and then digested completely with S1 nuclease and subjected to electrophoresis on polyacrylamide gel. By this technique, nuclear RNA that could hybridized to cDNA was found to have the albumin mRNA sequence in at least the 3' half of the mRNa that was covered by cloned cDNA. For comparison of the structures of the albumin genes of analbuminemic and normal rats...