bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Na‐K)ATPase activity along the nephrons in normal and adrenalectomized rats measured by quantitative cytochemistry
Authors: Snarski Joanna , Snarski Andrzej , Bachelet Marie , Bader Cyril , Ulmann André 
Published: May 2005

AbstractA cytochemical method was used to measure total, ouabain insensitive and specific (Na‐K)ATPase activities along the rat nephron. Enzyme activity was expressed as per cent of mean integrated extinction with reference to a calibrated filter. The lowest mean values of total, ouabain‐insensitive, and (Na‐K)ATPase activities were found in the proximal convoluted tubule (PCT). In the distal convoluted tubule (DCT), total and ouabain‐insensitive activities (77·8 per cent and 45·8 per cent, respectively) were significantly higher than in the medullary thick ascending limb (MAL) (66·0 per cent and 24·6 per cent, respectively). Mean values of (Na‐K)ATPase activity were significantly lower in DCT than in MAL (32·0 per cent and 41·3 per cent, respectively). Using Lineweaver‐Burk plots, the KM ATP value for total ATPase activity was found to be 2·33, 1·79, and 3·63 mM in DCT, MAL, and PCT respectively. Maximal velocity was lower in PCT than in MAL and DCT. For (Na‐K)ATPase, the smallest KM value was found in MAL (0·95 mM) and was 2·73 and 5·71 mM in DCT and PCT respectively. Maximal velocity was the highest in MAL (49·3 per cent), lower in DCT (36·1 per cent) and least in PCT (22·5 per cent). ATPase was measured in the MAL and DCT from rats fed a normal (N‐Na+) or a high (Hi‐Na+) sodium diet, and from Hi‐Na+ rats one week after adrenalectomy (ADX). In the MAL, (Na‐K)ATPase tended to be higher in Hi‐Na+ than in N‐Na+ rats, but was significantly lower in ADX than in Hi‐Na+. A significant correlation was found between daily urinary Na excretion and (Na‐K)ATPase in N‐Na+ and Hi‐Na+ animals (UNa = 0·19 (Na‐K)ATPase − 3·10, n = 15, r = 0·53, P > 0·05). In the DCT, variations between N‐Na+ and ADX rats were minimal. ADX abolished the difference in (Na‐K)ATPase between MAL and DCT.In summary, quantitative microdensitometry appears a suitable method for measuring (Na‐K)ATPase along the nephron, and this study indicates that the Na content of the diet and adrenal hormones modulate (Na‐K)ATPase in the MAL.
Improved rapid autoradiography with elimination of background
Authors: Spiridonidis Charalampos , Raza Azra , Zhao Shi‐Cheng , Preisler Harvey D. 
Published: May 2005

AbstractA method has been developed to improve the quality of autoradiography. In addition to using high specific activity thymidine (3HTdr), low temperature exposure and scintillation fluid. FdUR was added to the cell suspension during incubation. It led to an increased amount of 3HTdr incorporation by the cells. By this method, the grain density over positive cells was increased and the background was minimal.
Utility and sensitivity of anti BrdU antibodies in assessing S‐phase cells compared to autoradiography
Authors: Raza Azra , Ucar Kalust , Bhayana Ranjan , Kempski Maureen , Preisler Harvey D. 
Published: May 2005

AbstractA rapid and convenient method for estimating S‐phase cells in a population was developed which detects bromodeoxyuridine (BrdU) incorporation into DNA by means of monoclonal anti‐BrdU antibodies. This immunofluorescence technique (RPMB technique) was compared to autoradiographic (ARG) detection of tritiated thymidine (3HTdr) grains incorporated into the DNA. Using incubation periods for BrdU and 3HTdr ranging from one minute to one hour and detecting their incorporation by ARG and RPMB techniques, it became apparent that the RPMB technique was far more sensitive than ARG in addition to being extremely easy to perform. Some possible utilities of the RPMB technique are discussed.
Rat gastrointestinal transglutaminase: Demonstration of enzyme activity and cell and tissue distributions
Authors: Patel Ella K. , Bruce Sally E. , Bjarnason Ingvar , Peters Timothy J. 
Published: May 2005

AbstractThe properties, tissue and cellular distribution of intestinal transglutaminase have been investigated. Transglutaminase was assayed with dimethylcasein and [14C]putrescine as substrates. The enzyme has maximum activity at pH 10, although more reliable assays are made at pH 9. Transglutaminase showed an absolute requirement for Ca2+ and exhibited linear assay kinetics. The Km for putrescine was approx. 0·15 mmol/I.Tissue distribution studies suggest transglutaminase is more active in the more muscular segments of the gut. The cellular localization in jejunum was investigated by sequential cell release techniques. Approximately 2 per cent of the total activity was found in the enterocytes and crypt cells. Most of the activity was in the submucosa and serosa suggesting an interstitial cell localization.Acute hypoplastic enteropathy induced by methotrexate was accompanied by a striking decrease in mucosal transglutaminase but the activity returned to control values by 72 h. There was no significant increase in activity during the period of intense crypt cell hyperplasia and it is concluded that intestinal transglutaminase is not implicated in crypt cell proliferation.
Morphological changes in CHO and VERO cells treated with T‐2 mycotoxin. Correlation with inhibition of protein synthesis
Authors: Trusal Lynn R. 
Published: May 2005

AbstractExposure of Chinese hamster ovary and African green monkey kidney cells to T‐2 mycotoxin resulted in several morphological changes which were related to inhibition of protein synthesis, the basic in vitro mechanism of action of the toxin. These changes, which occurred in both cell types, included disassociation of polysomes and mitochondrial cristae alterations. In addition, CHO cells displayed membrane bleb formations similar to those found in CHO cells after exposure to established inhibitors of protein synthesis, puromycin and anisomycin. Blebs could be either a result of protein synthesis inhibition or a non‐specific early pathological response. Bleb formations were not observed in VERO cells under any experimental condition.
Heterogeneity of angiotensin II receptors in membranes of developing rat metanephros
Authors: Uva B. , Vallarino M. , Ghiani P. 
Published: May 2005

AbstractSpecific and high affinity binding sites for angiotensin II were demonstrated in the membranes of the developing rat metanephros during the second half of pregnancy and in the newborn by binding studies with 125I angiotensin II. Only one type of angiotesin receptor was found during intrauterine life while after birth two classes of angiotensin receptors were present in the membranes of the cortical renal tissue.
Effects of protease inhibitiors on adenylate cyclase activation and aldosterone production in rat adrenal zona glomerulosa cells
Authors: McAuley M. E. , Raven P. W. , Vinson G. P. 
Published: May 2005

AbstractIt has been shown that serine proteses are involved in aldosterone and 18‐hydroxycorticosterone production by the rat adrenal zona glomerulosa in response to a variety of stimulants. From evidence presented for various tissues, including the rat adrenal cortex, the observation that adenylate cyclase can be activated by proteolytic enzymes and inhibited by protease inhibitors has led to the suggestion that serine proteases may also be involved in the hormonal stimulation of adenylate cyclase. In studies designed to test this hypothesis using protease inhibitors, only high concentrations (>10−4M) of TAME (p‐tosyl‐L‐arginine methyl ester) inhibited ACTH stimulated steroid and cAMP production in rat adrenal glomerulosa cells. TPCK (tosyl‐L‐phenylalanine high concentrations) and TLCK (tosyl‐L‐lysine chloromethylketone) were found to have a similar effect at very high concentrations (10−2 M) but had no effect at the serine protease inhibitory concentration of 5 × 10−6 M. Other protease inhibitors tested had no effect on ACTH‐stimulated cAMP but the inhibitory effect of high concentrations of protease inhibitors on ACTH‐stimulated adenylate cyclase was duplicated by the polyanion dextran sulphate. The results suggest that the inhibitors act through non‐specific membrane effects and that proteases are not involved in the activation of zona glomerulosa adenylate cyclase by ACTH. In view of these findings it is concluded that a more rigorous approach should be applied to the use of protease inhibitors in whole cell systems, and that the concept of hormonal activation of adenylate cyclase via proteolytic events, which is based on studies with such inhibitors, should be reconsidered.
Differences among primates in defence against infection: Sensitivity of polymorphonuclear leukocytes to fMet‐Leu‐Phe
Authors: Suzuki Kazuo , Asaoka Kazuo , Takahashi Kenji , Fujikura Toshio 
Published: May 2005

AbstractThe sensitivity of polymorphonuclear leukocytes (PMN) to N‐formyl‐methionyl‐leucyl‐phenylalanine (fMet‐Leu‐Phe) for chemotaxis and for lysosomal enzyme release was examined using the PMN of four primate species, human (H. sapiens), chipanzee (P. troglodytes), rhesus monkey (M. mulatta), and cotton‐heded tamarin (S. (O) oedipus). The 50 per cent effective concentration (EC50) of fMet‐Leu‐Phe for chemoxaxis were 2·5 × 10−9 M in human, 10−9 M in chimpanzee, 8 × 10−8 M in rhesus moneky, and 3·3 × 10−6 M in tamarin. The EC50 values of fMet‐Leu‐Phe for myeloperoxides (MPO) release were 10−8 M in human, 4 × 10−8 M in chimpanzee, 4 × 10−8 M in rhesus monkey, and 10−6 M in tamarin and those for β‐glucuronidase release were 4 × 10−9 M, 6·4 × 10−8 M, 1·8 × 10−7 M, and 1·6 × 10−6 M, respectively. Thus, the sensitivity of fMet‐Leu‐Phe for chemotaxis was in the order: chimpanzee ≃ human > rhesus monkey > tamarin, and that for the release of lysosomal enzymes, MPO and β‐glucuronidase, was in the order: human > chimpanzee > rhesus monkey > tamarin.These results appear to indicate that the sensitivity to fMet‐Leu‐Phe increases in the order of evolution of primates towards the human, and suggest that the sensitivity to fMet‐Leu‐Phe increases in the order of evolution of primates towards the human, and suggest that the sensitivity of PMN in the defence function against infection also increases in the same order.
Stimulation of tissue plasminogen activator production from epithelial cell lines
Authors: Electricwala Asgar , Griffiths Bryan 
Published: May 2005

AbstractThe aim of this study was to investigate the possibility of enhancing the yield of tissue plasminogen activator (tPA) from two epithelial cell lines of normal (non‐malignant) derivation grown in tissue culture. The three agents used in this investigation were chosen because of thier proven enhancing effect on analogous cells or products. The anabolic hormone stanozolol was found to have no significant stimulatory effect on these cell lines. A phorbol acetate (12‐O‐tetradecanoylphorbol 13‐acetate) caused a twofold enhancement in tPA yield but the most significant results were obtained with 5‐azacytidine. This agent increased the yield by up to fourfold in small stationary cultures and threefold in large‐scale microcarier cultures. A combination of azacytidine and phorbol acetate did not have an additive effect on total yield but did alter the kinetics of tPA expression with time. Indications were that the maximum yield with these types of potentiating agents was achieved as it could not be increased by using a combination of two different agents.
Fasting‐induced dissociation of cationic and secretory events in pancreatic islets
Authors: Carpinelli A. R. , Mathias P. C. F. , Leclercq‐Meyer V. , Malaisse W. J. 
Published: May 2005

AbstractIn pancreatic islets removed from 48 h‐fasted rats, as distinct from fed animals, the release of insulin evoked by D‐glucose is more severely impaired than that evoked by 2‐ketoisocaproate. This decreased secretory response to D‐glucose contrasts with an unimpaired cationic response to the sugar in terms of the glucose‐induced decrease in both 86Rb and 45Ca outflow from pre‐labelled islets. Likewise, fasting only causes a modest decrease of the secondary rise in 45Ca outflow evoked by D‐glucose in islets perifused at normal Ca2+ concentration. The latter decrease appears more marked, however, if the cationic response to glucose is expressed relative to that evoked by 2‐ketoisocaproate in islets removed from rats in the same nutritional state. It is concluded that, in the process of nutrient‐stimulated insulin release, neither the decrease in K+ conductance (inhibition of 86Rb outflow) nor the sequestration of Ca2+ by intracellular organelles and/or direct inhibition of Ca2+ outward transport (decrease in 45Ca outflow) represent the sole determinant(s) of the subsequent gating of Ca2+ channels (secondary rise in 45Ca efflux).
Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine
Authors: Tsuboi Kenneth K. , Kwong Linda K. , Fan Quing , Thompson Diana J. , D'Harlingue Arthur E. , Sunshine Philip 
Published: May 2005

AbstractHydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase‐isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone‐treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase‐isomaltase pools was generally similar in the hydrocortisone‐treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rats of the carbohydrates as a group were found to be similar and did not appear to differ in control and hydrocortisone‐treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone‐treated group of rats.
Isolated adipocytes: An assessment of cell surface changes during their preparation
Authors: Al‐Jafari Abdulaziz A. , Lee Stephen R. , Tume Ronald K. , Cryer Anthony 
Published: May 2005

AbstractA method is described, based on the detection of adipocyte‐specific cell surface antigens, which allows assessement of the relative surface damage incurred by the cells when they are prepared under a variety of conditions. Using the method it is possible to develop, for any set of reagents, a set of cell isolation conditions (collagenase concentration, time of incubation) which will produce minimally damaged cells which exhibit high levels of specific cell surface immunoreactivity. Under certain conditions a recovery from limited surface damage can be achieved, although, when cells are prepared under more extreme conditions irreversible surface damage occurs. The surface morphology of the cells as revealed by scanning electron microscopy, is also clearly affected by the conditions of cell isolation. The method has been used to define the conditions necessary for the isolation of cells to be used in the study of subtle biochemical responses.
Aggregation states of cyclic nucleotide phosphodiesterase of murine thymocytes
Authors: Sobolev A. S. , Rybalkin S. D. 
Published: May 2005

AbstractIn murine thymocytes cyclic nucleotide phosphodiesterase is represented by cAMP‐ and cGMP‐specific forms. cAMP and cGMP phosphodiesterase activities showed anomalous kinetic behaviour indicative of ‘low’ and ‘high’ affinity enzyme forms. Sucrose density gradient centrifugation resolved only ‘low’ affinity forms of cAMP and cGMP phosphodiesterases. Gel filtration on Ultragel Aca 34 column showed that cAMP and cGMP phosphodiesterases are probably oligomeric enzymes. Storage of enzyme preparation at 4°C for 24–48 h led to a decrease of higher molecular weight form and enhancement of cAMP and cGMP phosphodiesterase activities.
Synergism between cytosolic and mitochondrial oxidation: Its possible relevance to the metabolism of vitamin D3 in the kidney
Authors: Bachelet Maria , Lair Micheline , Thomas Michäel , Monet Dominique , Ulmann André , Bader Cyrille 
Published: May 2005

AbstractUsing frozen liver sections and quantitative cytochemistry it has been established that when cells are allowed to oxidize a cytoplasmic and a mitochondrial substrate simultaneously the resulting oxidative activity is markedly higher than the sum of the oxidation of each substrate measured separately. In the present study this type of synergistic interaction has been confirmed in the kidney, particularly in cells of the pars recta. Our results support the evidence of the influence of cytoplasmic NADPH on the intramitochondrial oxidative process and it is suggested that, in cells of the pars recta, cytosolic NADPH may be involved in intramitochondrial mixed function oxidases such as 1α‐hydroxylase: these results could further elucidate the mechanism responsible for the production of the hormonal form of vitamine D3.
Differentiation of myeloid cells in liquid culture. 1. Progenitor cells found in normal perpheral blood
Authors: Archimbaud Eric , Preisler Harvey D. 
Published: May 2005

AbstractIn order to establish a method for studying myeloid differentiation, light density, non‐adherent, T‐cell depleted mononuclear cells prepared from 26 normal peripheral blood buffy‐coats were cultured in McCoy' 5A medium supplemented with 15 per cent fetal calf serum (FCS) for three weeks at 37°C in a humidified 5 per cent CO2 atmosphere. The total number of viable cells in the cultures on weeks 1 and 2 represented 73 ± 10 per cent and 98 ± 41 per cent of the initial number of viable cells seeded. After one week, blasts represented 26 ± 10 per cent of the initial number of viable cells while all the initially contaminating mature granulocytes had disappeared. After two weeks, granulocytic differentiation was noted in most cultures and viable myelocytes and more mature cells represented 45 ± 26 per cent of the initial number of viable cells. The differentiation was independent on the lot of FCS used. The addition of PHA stimulated leukocyte conditioned medium to the cultures did not enhance granulocytic differentiation. The granulocytic differentiation observed in the absence of exogenous CSF persisted after removing the cells adhering to the bottom of the flasks on day 2 of the culture. An endogenous colony stimulating activity was detected in the cultures on week 3 but its intensity did not clearly correlate with the degree of granulocytic differentiation.
Biochemical aspects of the mechanism of action of antiarrhythmic drugs on mitochondria. VII. Effect on energy‐linked reactions and on membrane potential
Authors: Klüppel Maria Lúcia Wambier , Borba Hélcio Resende , Silveira Orieta , Lopes Luiz Carlos Vieira , De Paiva Campello Annibal 
Published: May 2005

AbstractEffects of the antiarrhythmic drugs (propranolol, perhexiline maleate, lidoflazine and iproveratril) on energy‐linked reactions and on membrane potential were studied. Propranolol, perhexiline maleate and lidoflazine inhibit the ATPase activity of undamaged and broken mitochondria, and of submitochondrial particles. All drugs are inhibitors of either ATP‐driven or of succinate‐driven reduction of NADP+. The antiarrhythmics promote a decrease in the membrane potential upon energization of the mitochondrial membrane by α‐ketoglutarate, succinate, or ATP. It was suggested that these drugs have a primary action on the mitochondrial membrane, thus altering the activities of membrane proteins (channels and enzymes).
Differential hemoglobin synthesis in murino erythroleukemic cells: Hemin effects
Authors: Zucker R. M. , Umlas M. E. , Decal D. L. , Whittington K. B. 
Published: May 2005

AbstractThe addition of butyric acid to murine erythroleukemic cells (clone T3C12) induced the cells to differentiate, producing adult hemoglobin (A, α2,β2) and an embryonic hemoglobin (E2, α2Y2). The subsequent addition of hemin to the differentiating cells increased the synthesis of adult hemoglobin four‐fold and the synthesis of embryonic hemoglobin two‐fold; the relative synthesis of the α and β globins increased more than the Y globin. The embyronic hemoglobin was expressed prior to the adult hemoglobin in differentiating cells.
Isolation and characterization of parenchymal cells from normal and cirrhotic rat liver
Authors: Zimmermann Thomas , Franke Hans , Dargel Rolf 
Published: May 2005

AbstractA technique is described for isolation of adult rat hepatocytes from micronodular cirrhotic livers based on a collagenase digestion procedure. Hepatocytes from normal livers and those chronically injured by thioacetamide did not differ with respect to the viability measured by the trypan blue exclusion test or to the cellular concentrations of protein and glycogen, but the triglycerde content of cells from cirrhotic livers was significantly reduced. Hepatocytes isolated from cirrhotic livers are ultrastructurally in a good state of preservation but they appear to be poorer than controls in RER membranes, although the well‐preserved mitochondria are somewhat richer in cristae. No differences were detected between the cell preparations in rates of gluconeogenesis and total de novo fatty acid synthesis, but the secreation of newly synthesized fatty acids was significantly reduced in cells from cirrhotic livers.Thus adult rat hepatocytes can be isolated from thioacetamide‐induced micronodular cirrhotic livers with high yield and morphological integrity. Differentiated functions are maintained in suspension for at least 4 h.
Subcellular calmodulin distribution in rat liver after CCl4 poisoning
Authors: Barrera G. , Parola M. , Paradisi L. , Albin L. , Dianzani M. U. 
Published: May 2005

AbstractDisturbed cellular calcium homeostasis has been observed during CCl4 poisoning, with an increase in calcium content 1 h after administration. Intracellular increase of calcium may be expected to alter membrane/cytosol distribution of calmodulin (CaM). This paper investigates changes in rat liver subcellular CaM distribution 30 min, 1 h and 2 h after CCl4 intoxication. The whole liver value remained unchanged, whereas the nuclear fraction increased and the microsomal and cytosolic fraction decreased. This may suggest that CaM is involved in the several liver cell alterations caused by CCl4 poisoning.
Biochemical and immunochemical determination of (Na+ + K+)‐ATPase content in subcellular fractions prepared from the avian salt gland: Evidence for enzyme heterogeneity
Authors: Addis John S. , Merrit William D. , Mazurkiewicz Joseph E. , Barrnett Russell J. 
Published: May 2005

AbstractSubcellular membrane fractions were prepared from the salt glands of osmotically‐stressed ducklings. Two fractions were characterized biochemically with respect to (Na+ + K+)‐ATPase, alkaline phosphodiesterase I, succinate dehydrogenase, esterase, and galactosyltransferase activities and immunochemically with respect to (Na+ + K+)‐ATPase. The ratios of the estimates of the (Na+ + K+)‐ATPase contents obtained biochemically and immunochemically from the two fractions differed by more than 2 X. The results are consistent with the presence of at least two molecular species of (Na+ + K+)‐ATPase, unevenly distributed between the two fractions.