bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of transferrin in uptake of non‐physiological metals into cells
Authors: Planas‐Bohene Felicitas , Taylor David M. , Duffield John R. , Darai Gholamreza 
Published: May 2005

AbstractAt physiological concentrations of citrate the uptake of 59Fe, 67Ga, and 239Pu into human type B lymphocytes of splenic origin is the same in viable and in non‐viable cells. Addition of transferrin has no effect on the uptake into non‐viable cells but in viable cells it increases the uptake of Fe and Ga but decreases that of Pu. Uptake decreases as transferrin concentration increases although this is less marked with Ga.
Is there any connection between heat inactivation of spectrin‐dependent ATPase and loss of smooth biconcave shape of red cells?
Authors: Mirčevová Libuše , Kodíček Milan , Mařík Tomáš 
Published: May 2005

AbstractSpectrin‐dependent ATPase activity was measured in membranes from native human erythrocytes and erythrocytes heated for 20 min at different temperatures. This activity was found to decline when the erythrocytes were heated at 48°C and higher. The break in ATPase activity corresponds to morphological changes in erythrocytes found by Crome and Mollioson [Brit. J. Haematol. (1964) 10, 137]. The role of spectrin‐dependent ATPase in erythrocyte shape maintenance is discussed.
Platelet membrane fatty acids in thrombocytosis due to myeloproliferative disorders
Authors: Leoncini G. , Maresca M. , Balestrero F. , Piana A. , Benatti U. , Armani U. 
Published: May 2005

AbstractThe fatty acid composition of platelet membranes has been analysed in patients with thrombocytosis due to myeloproliferative disorders, who had not taken any drugs. A significant increase in palmitic and oleic acid, together with a decrease in stearic, linoleic and arachidonic acids was observed. The fatty acid pattern of platelet membranes was also analysed in patients during treatment with ASA (acetylsalicylic acid). ASA ingestion completely normalizes the platelet content of palmitic acid and partially that of stearic and arachidonic acid, whereas it has no effect on the level of linoleic acid and raises that of oleic acid. The altered pattern of fatty acids observed in patients may interfere with platelet function by decreasing membrane fluidity. Treatment of patients with ASA seems to act on platelet membranes by partially normalizing the fatty acid composition.
Nude mice injected with DNA released by antigen stimulated human tlymphocytes produce specific antibodies expressing human characteristics
Authors: Anker P. , Jachertz D. , Maurice P. A. , Stroun M. 
Published: May 2005

AbstractNude mice were injected with DNA purified from the nucleoprotein complex released by T lymphocytes previously exposed in vitro to inactivated herpes or poliovirus. After five days the serum of these mice was tested for its virus neutralizing activity. Results show that injected nude mice synthesize antiherpetic or antipolio antibodies depending on the antigen used to sensitize the T lymphocytes in vitro. These antibodies were not found in the serum of uninjected control mice or mice injected with inactivated herpes or polio viruses. Mice injected with DNA release by human T cells produced antibodies carrying human allotypes since they could be neutralized by anti‐allotype sera. Moreover their antiviral activity was inhibited by anti‐human IgM or IgG. However, the mice which were injected with DNA released by antigen stimulated murine T lymphocytes produced antiviral antibodies which were not neutralized by anti‐human allotype sera.
Characteristics of taurine transport in rat hepatocytes in primary culture
Authors: Ohkuma Seitaro , Tamura Jun‐ichi , Kuriyama Kinya , Mukainaka Teruo 
Published: May 2005

AbstractCharacteristics of taurine transport in rat hepatocytes maintained in primary culture for 24 h (cultured hepatocytes) have been investigated. The uptake of [3H] taurine by cultured hepatocytes at 2°C was unsaturable, whereas that at 37°C consisted of unsaturable and saturable processes. The saturable transport system was sodium‐dependent and consisted of two processes with low and with high affinities. The latter process (Km, 76.9 μM; Vmax, 0.256 nmole/mg protein/min; activation energy (EA), 37.8 kcal mol−1) was competitively inhibited by 2,4‐dinitrophenol and ouabain, as well as by taurine analogues such as hypotaurine and guanidinoethyl sulphonate. The Vmax and EA values found in cultured hepatocytes at 37°C were 6.0 and 6.8 times higher than those found in freshly isolated hepatocytes. These results indicate that taurine transport in hepatocytes in primary culture consisted of unsaturable, and saturable, sodium and energy‐dependent carrier‐mediated transport processes, respectively. The facilitation of the latter transport system by primary culture of hepatocytes is also suggested.
Functional alterations of the endoplasmic reticulum and the detoxification systems during diethyl‐nitrosamine carcinogenesis in rat liver
Authors: Garcea R. , Canuto R. A. , Biocca M. E. , Muzio G. , Rossi M. A. , Dianzani M. U. 
Published: May 2005

AbstractThe mixed‐function oxidase system shows a number of variations in the liver of diethyl‐nitrosamine (DEN) treated rats. These include a decrease of the cytochrome P450 content and of the aminopyrine demethylase activity both in the hyperplastic nodules and in the hepatoma. Processes of detoxification, such as the glutathione system, show some modifications. These alterations are in accordance with the decrease of glutathione peroxidase and the increase of γ‐glutamyltranspeptidase during diethyl‐nitrosamine carcinogenesis.
Stimulation by cholera toxin of ADP‐ribosylation of membrane proteins, adenylate cyclase and insulilin release in pancreatic islets
Authors: Svoboda Michael , Garcia‐Morales Pilar , Dufrane Simon P. , Sener Abdullah , Valverde Isabel , Christophe Jean , Malaisse Willy J. 
Published: May 2005

AbstractIn rat pancreatic islet membranes exposed to [α–32P]NAD, cholera toxin stimulated the labelling of three peptides with Mr close to 22000, 42000 and 48000, respectively. In the islets, the toxin‐stimulated ADP‐ribosylation of the heavy form of the Ns α‐subunit predominated over that of the light from, in mirror image of the situation found in the exocrine pancreas. When intact islets were preincubated with cholera toxin, the adenylate cyclase activity of a subcellular particulate fraction was increased. The responsiveness of adenylate cyclase to GTP was also augmented, but that to NaF was decreased. In intact islets, the production of cyclic AMP and the glucose‐stimulated release of insulin were also enhanced after pretreatment with cholera toxin. These findings reveal the presence in pancreatic islets of the guanyl nucleotide regulatory protein of adenylate cyclase, with an unusual predominance of the heavy from of the Ns α‐subunit.
Alpha‐Lactalbumin as a lysosomal enzyme‐releasing factor
Authors: Komine Senichi , Nakanishi Keiko , Anzaio Tadashi , Yoshimoto Akio 
Published: May 2005

AbstractIn the early stage of mammary gland involution, biochemically detectable lysosomal damage occurs. The mechanism(s) underlying this damage is not well understood. We found that α‐lactalbumin from mouse milk induced the release of enzymes from the lysosomes of mouse mammary epithelial cells in vitro, and this induction also occurred with bovine α‐lactalbumin. This enzyme release was accelerated by the addition of whey proteins with a molecular weight of 50 000 to 60 000. We also found that the lysosomal membrane of mammary epithelial cells had a strong affinity for α‐lactalbumin.
A catabolin‐like factor from porcine kidney
Authors: Monserrat J. Juan , Dingle John T. 
Published: May 2005

AbstractExplants of pig kidney cortex and medulla release a catabolin‐like factor (CLF). The CLF of both kidney cortex and medulla can be precipitated with ammonium sulphate, mainly in the 60–95 per cent fraction. By gel chromatography the kidney CLF showed a major active fraction at a molecular weight of around 22 500.Whole glomeruli and dissociated glomerular cells in culture also released into the medium a CLF that could be bioassayed in live cartilage but displayed no effect on dead cartilage. The possible role of such a local hormone is discussed.
Triiodothyronine receptor sites in serum‐free cultured hepatocytes from adult rat liver
Authors: Goglia F. , Gallo G. , Palmero S. , Voci A. , Fugassa E. 
Published: May 2005

AbstractNuclear T3 specific binding sites were characterized by Scatchard analyses of L‐125I‐T3 binding to nuclei extracted from freshly isolated and 1,2 and 6 day‐cultured hepatocytes. The results demonstrate a marked decrease in T3 binding capacity of nuclei extracted from 1 day‐cultured cells followed by an almost complete recovery within 6 days. The affinity constant value of nuclear receptor sites is significantly decreased in 1 day‐cultured cells with a subsequent partial recovery. The affinity and capacity pattern of nuclear T3 binding sites appears to be in line with the delayed responses of hepatocyte primary cultures to T3.
The relationship between tissue preparation and function; methods for the study of control of aldosterone secretion: A review
Authors: Vinson G. P. , Hinson J. P. , Raven P. W. 
Published: May 2005

AbstractThe study of the control of aldosterone synthesis and secretion by the rat adrenal gland has over the past thirty years involved the application of many different in vivo and in vitro techniques. In this review the relationship between the data that each of these methods has produced is compared. There are striking differences in overall steroid production rates, and in the qualitative nature of the steroid profile which the various methods produce. In particular, aldosterone is secreted at higher rates in vivo, and when whole tissue preparations are used in vitro, than in incubations of isolated glomerulosa cells. In addition, while corticosterone is a major product of glomerulosa tissue in vitro, the available evidence suggests that it is not a major glomerulosa product in vivo.
[Na‐K]ATPase activity in proximal and distal tubules of the rat kidney: Modification and application of a quantitative cytochemical technique
Authors: Hersey Roscoe M. , Gattone Vincent H. , Weisz Judith 
Published: May 2005

AbstractA modified cytochemical assay for [Na‐K]ATPase in cryostat sections of kidney was further characterized and used to quantify activity in seven functionally distinct sites along the rat nephron. The activity of [Na‐K]ATPase was defined as the difference in ATPase activity in specifically identified tubules contained in serial sections incubated with and without ouabain. Preincubation of sections with ouabain was required for maximal inhibition of [Na‐K]ATPase activity in several distal sites. The concentration of oubain necessary for maximal inhibition of activity was 3·0 mM and half‐maximal inhibition was obtained in all regions with 30–100μM ouabain. In distal sites, [Na‐K]ATPase formed a higher proportion of total ATPase activity (60–80 per cent) than in proximal sites(20–40 per cent). Enzyme activity was quantified using two different methods. The first measured activity over the basal region of tubules and gave an index of the concentration of [Na‐K]ATPase over the basal lateral infoldings of cells composing the tubule. The second read activity over the entire cross section of tubules and provided an estimate of [Na‐K]ATPase per length of tubule. The highest activities over the basal region were obtained from tubules of the distal nephron including the inner (MALin) and outer (MALout) medullary ascending limb, distal convoluted tubule (DCT) and connecting segment (CS). Lower activities were obtained in proximal convoluted (PCT) tubules, proximal straight (PS) tubules and the papillary collecting duct (PD). Distal convoluted tubules contained the highest activity per length of tubule. Other sites contained lower levels of activity in the following order: MALin > MALout > PCT > PD > PS. The modifications introduced increase the sensitivity and precision of this assay and permit the application of this technique to studies of [Na‐K]ATPase activity in the major functional regions of the rat nephron.
Differential sensitivity to trypsin of human bone‐derived cells in culture: Surface changes detected by partitioning in aqueous two‐phase systems
Authors: Sharpe P. T. , Gallagher J. A. , Macdonald B. R. , Treffry T. E. , Russell R. G. G. 
Published: May 2005

AbstractHuman bone‐derived cells, grown in monolayer culture, were dissociated by incubations with trypsin/EDTA and subjected to thin‐layer counter‐current distribution in a ‘low potential’ aqueous two‐phase system. Two major populations of cells were detected. The number of cells in the second (more hydrophobic) population increased with length of trypsinization and time in culture. Cells allowed to ‘regain’ surface molecules lost by trypsinization did not produce the second population.Cells occupying the second population after a short period of trypsinization had a lower rate of division than peak 1 cells but showed a higher rate of protein synthesis per rate of division than peak 1 cells.These results show that the cells have markedly different sensitivities to trypsin digestion which may be related to cell division rate of growth. The possible relationship between this and osteoblast development are discussed.
The suppression of endogenous protein degradation by fractions of foetal calf serum: Dialysed serum is less able to suppress degradation in aged cells
Authors: Wharton S. A. , Riley P. A. 
Published: May 2005

AbstractWe have studied the effect of various fractions of foetal bovine serum upon the endogenous degradation of long labelled proteins in cultured MRC5 cells, and upon other cellular functions. Only heat‐inactivated serum was capable of suppressing protein degradation to a similar extent to complete serum. Acid‐treated and delipidized sera were moderately effective. Albumin on its own was able to replace 40 per cent of the effect of serum, indicating the exogenous protein might compete with endogenous protein for degradation in lysosomes. Albumin was not capable of supporting DNA synthesis. Dialysed serum showed an age‐related effect suppressing protein degradation to a lesser extent and being less effective in supporting DNA synthesis or cellular proliferation in aged cells. All the effects noted were related to lysosomal protein degradation. Serum diffusate did not suppress protein degradation.
Red blood cell phagocytosis and lysis following oxidative damage by phenylhydrazine
Authors: Magnani M. , Stocchi V. , Cucchiarini L. , Chiarantini L. , Fornaini G. 
Published: May 2005

AbstractRed blood cells exposed in vitro to phenylhydrazine acquired Heinz bodies, bound autologous IgG and were then phagocytized when incubated with autologus mononuclear phagocytes. In vivo, phenylhdyrazine administered to rabbits, caused the appearance of high plasma hemoglobin levels and hemoglobinuria as well as Heinz body formations and IgG binding to erythrocytes. This suggests that while in vitro the main mechanism of red cell removal seems to be phagocytoses, in vivo both intravascular hemolysis and phagocytosis are active processes.Preliminary biochemical studies on phenylhydrazine‐exposed erythrocytes showed that together with the well‐known appearance of Heinz bodies, methemoglobin and a drop in reduced glutathione, this drug also causes ATP depletion. This is initially concomitant with the appearance of ADP and AMP and subsequently hypoxantine. Thus, irreversible ATP depletion may contribute to the genesis of the hemolytic process observed in vivo.
The effects of acute phosphate depletion on isolated chick kidney tubule cells
Authors: Grahn Michael F. , Butterworth Peter J. 
Published: May 2005

AbstractIsolated tubule cells from chick kidney respond to a short period of phosphate deprivation with increased phosphate uptake and a resistance to parathyroid hormone. During phosphate depletion a considerable amount of phosphate may be released from the cells, but intracellular inorganic phosphate levels are maintained by the hydrolysis of organic phosphate esters. It is suggested that the concomitant changes in metabolism might act as the signal causing the onset of the changes in phosphate handling associated with phosphate deprivation.
Phospholipids in chromatin: Incorporation of [32P]O in different subcellular fractions of hepatocytes
Authors: Viola‐Magni M. P. , Gahan P. B. , Albi E. , Iapoce R. , Gentilucci P. F. 
Published: May 2005

AbstractNuclear, chromatin and microsomal fractions were isolated from hepatocytes prepared from rats injected with [32P] O and killed subsequently at times between 1 and 48 h. Specific activities of the total phospholipids (PL) were determined for each subcellular fraction. The major points noted were (a) the initial specific activity of the chromatin PL was half that of both nuclear and microsomal PL at 1 h; (b) the first peak of labelling occurred at 6 h in both nuclear and microsomal PL, but was 3 h later (9h) in the chromatin PL; and (c) a second peak of labelling occurred in the chromatin and microsomal PL, but not in those of the nuclei.On fractionation of the PL, the major and most metabolically active components were phosphatidylcholine + phosphatidylethanolamine, whilst sphingomyelin accounted for only about 8 per cent of the total PL. The chromatin and microsomal fractions were somewhat similar in their labelling patterns though with a delayed peaking of activity in the chromatin. This is indicative of a synthesis and transport of PL from the microsomes to the chromatin.
Aerobic glycolysis: A study of human articular cartilage
Authors: Nahir A. M. 
Published: May 2005

AbstractCartilage generally is one of those tissues that exhibit aerobic glycolysis. In a previous study on rat epiphyseal cartilage it had been suggested that this phenomenon is related to potentially excessive production of pyruvate and acetyl coenzyme A, the latter derived from fatty acid oxidation and inhibiting pyruvate dehydrogenase activity. The present study has shown that, in human articular cartilage, the contribution from fatty acid oxidation is too small to account for this phenomenon although the total potential production of pyruvate could still be in excess of the requirements for acetyl coenzyme A for the Krebs' cycle. Of greater relevance may be the apparent correlations that have been found between the activities of lactate and glyceraldehyde 3‐phosphate dehydrogenases (r = 0·82: 0·01 > p > 0·001) and between those of lactate and glucose 6‐phosphate dehydrogenases (r = 0·92; p < 0·001).
Relationship between melanin content and superoxide dismutase (SOD) activity in the liver of various species of animals
Authors: Schiel G. , Corsaro C. , Scalia M. , Sciuto S. , Geremia E. 
Published: May 2005

AbstractThe scavenger effect of melanin and of superoxide dismutase (SOD) activity on superoxide anion has been shown. In this work we show the relationship between melanin content and SOD activity in livers containing different quantities of melanin which were taken from various species of animals. The mitochondrial SOD activity disappears when the melanin content in the liver is very high; moreover it increases, in the liver of various species of animals examined, proportionally to the decrease of melanin content. No significant variation of the SOD activity localized in the soluble fraction has been detected when related to the melanin content. We think that in the pigmented liver the antioxidant activity of the melanin could mimic part of the function of SOD. The loss of Mn SOD activity could be mediated by a low intracellular level of superoxide anion due to the scavenger effect of melanin on superoxide anion; in fact, it is well known that the biosynthesis of Mn SOD is induced by intracellular levels of superoxide anion.
Avian thrombocyte thrombospondin
Authors: Wachowicz Barbara , Krajewski Tadeusz , Przybylska Maria 
Published: May 2005

AbstractA high molecular weight glycoprotein (450 000) was obtained from thrombin‐treated duck thrombocytes by barium citrate adsorption technique followed by heparin‐agarose affinity chromatography. Amino acid composition (high number of acidic amino acids and cystine) as well as carbohydrate contents (1·3 per cent hexosamine, 0·9 per cent sialic acid and 1·5 per cent hexose) showed similarity to mammalian platelet thrombospondin.
Liver and biliary levels of glutathione and thiobarbituric acid reactants after acute lindane intoxication
Authors: Videla Luis A. , Barros Silvia B. De M. , Simizu Kiyoko , Junqueira Virgínia B. C. 
Published: May 2005

AbstractThe i.p. administration of 60 mg kg−1 body weight of lindane, the γ‐isomer of hexachlorocyclohexane, to fed rats led to an enhancement of hepatic lipid peroxidation after 24 h of treatment. This was evidenced by significant increases in the hepatic production and biliary release of thiobarbituric acid reactive substances, and in the biliary release of glutathione disulphide. Under these conditions, the content of cytochrome P450 was enhanced concomitantly with increases in the total microsomal oxygen uptake, superoxide radical generation and (+)‐catechin (cyanid‐3‐ol) sensitive respiration. The glutathione status of hepatocytes was altered by lindane as the content and biliary release of glutathione disulphide was drastically augmented, leading to a decrease in the cellular and biliary GSH/GSSG ratios. It is suggested that lindane treatment leads to an induced oxidative capacity, which, in turn, alters the glutathione status of the liver tissue.
Methotrexate: Studies on the cellular metabolism. I. Effect on mitochondrial oxygen uptake and oxidative phosphorylation
Authors: Yamamoto Nair , Oliveira Ma Benigna Martinelli , Campello Annibal De Paiva , Lopes Luiz Carlos Vieira , Klüppel Ma Lúcia Wambier 
Published: May 2005

AbstractEffect of methotrexate (MTX) on mitochondrial oxygen uptake, oxidative phosphorylation and on the activity of several enzymes linked to respiratory chain was studied. MTX was able to inhibit state III respiration activated by ADP and to decrease the respiratory coefficient with the substrates α‐ketoglutarate and glutamate; these effects became pronounced when mitochondria were pre‐incubated with MTX for 10 min. No effect was observed on ATPase activity of undamaged or broken mitochondria; the same was true for NADH‐oxidase, NADH‐dehydrogenase, NADH‐cytochrome c reductase, succinate oxidase, and cytochrome c oxidase activity. The effect on the steady‐state of cytochrome b, as well as, the inhibitory effect on state III of respiration with NAD+‐linked substrates, offers a reasonable possibility to suggesting that the inhibition site of MTX could be in a place anterior to cytochrome b region, and not linked to respiratory chain.