bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of β‐adrenergic stimulated calcium pump of rat cardiac sarcoplasmic reticulum by tricyclohexyltin hydroxide
Authors: Sahib I. Kabeer Ahammed , Desaiah D. 
Published: May 2005

AbstractThe effects of tricyclohexyltin hydroxide (Plictran), an organotin acaricide, on 45Ca2+ uptake and Ca2+ ATPase were studied in vitro and in vivo in rat heart ventricular membrane vesicles, primarily sarcoplasmic reticulum. There was a concentration dependent inhibition of both 45Ca2+ uptake and Ca2+ ATPase in vivo as well as in vitro. Isoproterenol, a β‐adrenergic agonist, stimulated 45Ca2+ uptake and Ca2+ ATPase of sarcoplasmic reticulum and this was also inhibited by Plictran. Since cardiac relaxation is mediated by β‐adrenergic stimulation via Ca+ uptake by sarcoplasmic reticulum, the inhibition of calcium pump activity by Plictran may result in alterations in cardiac Ca2+ fluxes leading to cardiac dysfunction.
Differentiation of myeloid cells in liquid culture: 2. Acute myelocytic leukemia cells
Authors: Archimbaud Eric , Preisler Harvey D. 
Published: May 2005

AbstractIn a companion paper13 we demonstrated that normal peripheral blood granulocytic precursor cells differentiate after 2–3 weeks in suspension culture. In the studies described here leukemic blast cells obtained from 14 patients with acute myelocytic leukemia (AML) and two patients with chronic myelocytic leukemia in blastic crisis were cultured in McCoy's 5A medium containing 15 per cent fetal bovine serum for 2–3 weeks at 37°C in an atmosphere of 5 per cent CO2–95 per cent room air. ‘Spontaneous’ myeloid differentiation (20 × 104 viable mature myeloid cells ml−1) occurred in the cultures of cells obtained from 8 pts. The differentiation was granulocytic in three cases, monocytic in four cases and of mixed type in one case. Differentiation was independent of the growth of the cells in culture and occurred in four cases after the first week. Monocytic differentiation was seen only in AML of the FAB M4 type whereas granulocytic or mixed differentiation were seen only in AML of the FAB M1 or M2 types. When PHA leucocyte conditioned medium (PHA‐LCM) was added to the cultures monocytic/macrophage differentiation was favoured. Inducers of the differentiation of the HL‐60 cell line (N‐methylacetamide, cytosine arabinoside, or retinoic acid) had no consistent effect on the differentiation and were at times inhibitory. Three patients received therapy with low dose cytosine arabinoside and no correlation was observed between the outcome of the treatment and leukemic cell differentiation in culture in the presence of the drug.
Recovery of human erythrocytes from the echinocyte shape induced by added choline‐phospholipids is dependent on the acyl chain length
Authors: Tamura Akira , Sato Takashi , Fujii Tatsuzo 
Published: May 2005

AbstractAddition of an amphiphilic lipid, such as phosphatidylcholine (PC) species with two identical saturated chains or lysophosphatidylcholine (lysoPC) species with one saturated acyl chain of various lengths, into a suspension of intact human erythrocytes resulted in lipid incorporation into the erythrocyte membrane to produce echinocytes (crenated cells). The altered shape gradually reverted on incubation at 37°C until the cells reassumed their normal disc shape. The rate of such recovery of shape increased with decreasing acyl chain length for both PC with C8–C12 acyl chains and lysoPC with a C14–C18 acyl chain, and was strongly influenced by incubation temperature. The identical rate of recovery of shape was observed for cells with normal, decreased or increased ATP content, implying that the metabolic state of the cell had no influence on the recovery process. Recovery of shape is therefore considered to be caused by translocation of the incorporated lipid molecules from the outer to the inner leaflet of the membrane lipid bilayer and the rate of recovery increases with decreasing hydrophobicity of the lipid.
Effect of cytochalasin b on glucose uptake, utilization, oxidation and insulinotropic action in tumoral insulin‐producing cells
Authors: Malaisse W. J. , Giroix M.‐H. , Sener A. 
Published: May 2005

AbstractCytochalasin B (17·3 μM) virtually abolished 3‐O‐methyl‐D‐[U‐14C]glucose uptake and D‐[5‐3H]glucose utilization in tumoral insulin‐producing cells of the RINm5F line. This coincided with a marked decrease in D‐[U‐14C] glucose oxidation and suppression of the stimulant action of D‐glucose upon insulin release. Cytochalasin B, however, augmented basal insulin release by the tumoral cells. The RINm5F cells appeared much more sensitive than normal islet cells to cytochalasin B, as judged by the relative magnitude of inhibition in either hexose uptake or utilization. In both cell types, the inhibitory action of cytochalasin B upon glucose metabolism seemed to be competitive, being more marked at low than high glucose concentration. These results are interpreted in support of the view that a decreased efficiency of hexose transport across the plasma membrane represents an essential deficiency of the RINm5F cells.
The preparative isolation of endosome fractions: A review
Authors: Mullock Barbara M. , Hinton Richard H. , Peppard Jane V. , Slot Jan W. , Luzio J. Paul 
Published: May 2005

AbstractThe endosome is an intracellular, acidic, membrane‐bound, subcellular compartment to which endocytosed ligands, receptors and plasma membrane proteins are conveyed before sorting and delivery to destinations elsewhere in the cell. The preparative isolation of elements of this compartment has been achieved successfully using various appropriate combinations of density gradient ultracentrifugation, electrophoretic, gel filtration and immunoaffinity techniques. These methods for isolating endosome fractions are reviewed together with the difficulties of establishing markers for such fractions. The isolation of an endosome fraction from the pathway of polymeric IgA transcytosis in rat liver is discussed to exemplify successful isolation procedures and appropriate subcellular markers.
A critical evaluation of the use of filipin‐permeabilized rat hepatocytes to study functions of the endoplasmic reticulum in situ
Authors: McEwen Bruce F. , Telford John N. , Handelman Caryl T. , Arion William J. 
Published: May 2005

AbstractWe have used transmission (TEM) and scanning electron microscopy (SEM) and leakage of lactate dehydrogenase (LDH; EC 1.1.1.27) to evaluate two published procedures which use filipin to render isolated rat hepatocytes permeable to ionic substrates. Cells treated by the procedure of Jorgenson and Nordlie6 retained less than 10 per cent of their LDH. TEM revealed severe damage to the internal structure of these cells, which included swelling, disintegration and extensive vesicularization of the endoplasmic reticulum (ER). Hepatocytes treated with filipin by the procedure of Gankema et al.13 retained 65–75 per cent of their LDH and displayed incomplete but highly variable permeability to Trypan blue. SEM revealed the loss of microvilli, other signs of swelling, and the presence of large lesions in the plasma membrane. TEM revealed signs of cell swelling, but the nuclei and the mitochondria were only moderately altered. The rough ER was not swollen, but significant fragmentation was evident and characteristic stacks of lamellar ER were never seen.We conclude that useful information about the functions of the ER in situ cannot be obtained from studies of filipin‐treated cell. Our results indicate that retention of LDH is not a sufficient criterion of preservation of cell morphology and that staining with Trypan blue may significantly underestimate the permeability of cells to small ionic metabolites.
Age‐Dependent changes in rat liver lipid peroxidation and glutathione content induced by acute ethanol ingestion
Authors: Videla L. A. , Fernandez V. , Valenzuela A. 
Published: May 2005

AbstractThe study of the influence of the age of animals (13 to 53 weeks) on total liver thiobarbituric acid reactive substances (TBAR) content showed an increase which is maximal in rats of 39 weeks of age compared to young animals (13 weeks), followed by a dimunition in the 53 weeks old group. In this situation, the content of hepatic GSH and total GSH equivalents as well as the GSH/GSSG ratio were decreased with ageing, while GSSG levels were enhanced in the oldest group studied. Acute ethanol intoxication resulted in a marked increase in liver TBAR content in young animals, together with a decline in GSH, total GSH equivalents and GSH/GSSG ratio, and an enhancement in GSSG. These changes elicited by ethanol intake were reduced with ageing. It is concluded that ethanol‐induced oxidative stress in the liver is diminished during ageing, despite the progressive decrease in the glutathione content of the tissue observed in control animals.
Initial adhesion of murine fibroblasts to collagen and fibronectin occurs by two mechanisms
Authors: Bauvois Brigitte , Roth Stephen 
Published: May 2005

AbstractThe adhesion of Balb/c 3T12 cells to fibronectin (FN) and to denatured (DC) or native (NC) collagen is differentially sensitive to divalent cations and to sodium azide. Short‐time adhesion (10 min) to FN requires either Mg2+ or Mn2+, whereas only Mn2+ stimulates attachment to DC and NC. Azide treatment only slightly affects adhesion of cells to FN, but strongly inhibits cell attachment to DC and NC. Attachment to any of these substrata is unaffected by monensin and by treatment of the cells with an intracellular fraction, making unlikely the possibility that molecules released by secretion or cell lysis participate in the adhesive process. Soluble collagen inhibits the adhesion of cells to DC and NC, but does not affect adhesion to FN. Finally, rabbit antiserum against collagen binding proteins inhibits cell attachment to NC and DC; the cells, however, attach normally to FN in presence of this antiserum. Taken together, our results support the view that 3T12 cells attach directly to native or denatured collagens and that FN is not required for this process.
Inactivation of alpha‐1‐proteinase inhibitor in serum by stimulated human polymorphonuclear leucocytes. Evidence for a myeloperoxidase‐dependent mechanism
Authors: Shock Anthony , Baum Harold 
Published: May 2005

AbstractTriggered polymorphonuclear leucocytes (PMNL) can decrease the elastase inhibitory capacity of serum by inactivating the main inhibitor of elastase alpha‐1‐proteinase inhibitor (alpha‐1‐PI). Maximal inactivation occurs with stimuli that release myeloperoxidase from PMNL along with hydrogen peroxide. Specific protection of alpha‐1‐PI function is obtained with antioxidants that interfere with this system. PMNL that are activated with phorbol myristate acetate release hydrogen peroxide but not myeloperoxidase, and only inactivate alpha‐1‐PI in the presence of exogenously‐added PMNL‐derived supernatants which contain this enzyme. Cell‐free inactivation requires both active enzyme and hydrogen peroxide, and is greatest at pH 6·2, the pH optimum for myeloperoxidase‐catalysed inactivation of alpha‐1‐PI. This data supports the notion that leucocyte myeloperoxidase may act to suppress the antiprotease screen afforded by alpha‐1‐PI by generating hypochlorous acid in the presence of chloride and respiratory burst‐derived hydrogen peroxide, and in the microenvironment of lowered pH associated with degranulation. Pulmonary emphysema seems to be associated with an imbalance between elastase and its inhibitors at the lung surface. PMNL are likely to play an important role in the pathogenesis of emphysema since they contain both elastase, which can solubilize connective tissue elastin, and the constituents of an oxidative system which can inactive the most important antielastase, alpha‐1‐PI.
Tightly‐bound non‐histone proteins in different nucleosome‐like subpopulations from pig kidney chromatin
Authors: Caiafa Paola , Tomassetti Antonella , Mastrantonio Stefania , Reale Anna , Spinelli Maurizio , Strom Roberto 
Published: May 2005

AbstractBy differential sucrose gradient centrifugation of pig kidney chromatin in the presence or absence of Na‐EDTA and under varying ionic strength conditions, three nucleosome‐like subpopulations with different buoyant densities can be obtained. These particles, on the basis of their histones and HMG protein pattern, of the 5‐methylcytosine level of their DNA and of the RNA polymerase activity associated with them, can be considered as originating from chromatin fractions differently involved in gene expression.Two‐dimensional electrophoresis of the tightly‐bound non‐histone proteins shows a distinct pattern for each subpopulation, such protein components being notably present in restricted numbers but in high amounts in the subpopulation which was apparently derived from condensed heterochromatin.
Lipid peroxidation in purified plasma membrane fractions of rat liver in relation to the hepatoxicity of carbon tetrachloride
Authors: Le Page R. N. , Cheeseman K. H. , Osman N. , Slater T. F. 
Published: May 2005

AbstractPreparations of rat liver sinusoidal plasma membrane have been tested for their ability to metabolize the hepatotoxin carbon tetrachloride (CCl4) to reactive free radicals in vitro and compared in this respect with standard preparations of rat liver microsomes. The sinusoidal plasma membranes were relatively free of endoplasmic reticulum‐associated activities such as the enzymes of the cytochrome P450 system and glucose‐6‐phosphatase. CCl4 metabolism was measured as (i) covalent binding of [14C]‐CCl4 to membrane protein, (ii) electron spin resonance spin‐trapping of CCl3· radicals and (iii) CCl4‐induced lipid peroxidation. By all of these tests, purified sinusoidal plasma membranes were found unable to metabolize CCl4.The fatty acid composition of the plasma membranes was almost identical to that of the microsomal preparation and both membrane fractions exhibited similar rates of the lipid peroxidation that was stimulated non‐enzymically by γ‐radiation or incubation with ascorbate and iron. The absence of CCl4‐induced lipid peroxidation in the plasma membranes seems to be due, therefore, to an absence of CCl4 activation rather than an inherent resistance to lipid peroxidation.We conclude that damage to the hepatocyte plasma membrane during CCl4 intoxication is not due to a significant local activation of CCl4 to CCl3· within that membrane.
Monoiodotyrosine formation during thyroglobulin processing in golgi vesicles
Authors: Bastiani P. , Rognoni J. B. 
Published: May 2005

AbstractA golgi‐enriched subfraction was obtained from porcine throid glands by differential centrifugation. When incubated in a suitable medium, these vesicles were able to concentrate iodide from the medium and bind it to protein. The iodination process was inhibited by methylmercapto‐imidazole and was increased by the addition of an H2O2 generating system to the medium. Analysis of the protein content of the vesicles revealed the presence of 18 and 12–13 S thyroglobulin molecules, lacking mannose residues, and containing only monoiodotyrosine.It is concluded that in vitro, iodination can begin before exocytosis, in the smooth‐surfaced vesicles derived from the golgi apparatus, as soon as N‐acetylglucosamine is incorporated onto the pre‐thyroglobulin molecule.
Ouabain‐insensitive active sodium transport in rat jejunum: Evidence from ATPase activities, Na uptake by basolateral membrane vesicles and in vitro transintestinal transport
Authors: Tosco M. , Orsenigo M. N. , Esposito G. , Faelli A. 
Published: May 2005

AbstractThe basolateral membrane of the jejunal enterocyte of the rat was separated by self‐orienting Percoll‐gradient centrifugation and further purified from brush border contamination. Pellets were analysed for Mg‐, Na‐ and (Na, K)‐ATPase activities. The uptake of 0·02 M NaCl was also followed by the rapid micro‐filtration technique. Transintestinal transport of fluid and electrolytes, and cell water, Na and K were determined in the in vitro everted and incubated jejunum.There is ouabain‐insensitive Na‐ATPase in addition to the well‐known (Na, K)‐ATPase in the basolateral membrane. These are differently inhibited by furosemide and ethacrynate. Na uptake by osmotically active basolateral membrane vesicles is enhanced by ATP and a further enhancement is obtained if there is intravesicular K. The ATP effect is inhibited differently by strophanthidin, furosemide and ethacrynate. In the everted sac preparation, transintestinal transport of Na and fluid still occurs when the Na/K pump is totally inhibited by ouabain.These experimental results suggest that there is also a ouabain‐insensitive Na pump, different from the Na/K pump, in the basolateral membrane.
Changes in ribonucleoprotein particle and chromatin organization induced by liposomes in isolated nuclei
Authors: Maraldi N. M. , Galanzi A. , Caramelli E. , Billi A. M. , Ognibene A. , Rizzoli R. , Capitani S. 
Published: May 2005

AbstractNuclei isolated from rat liver, incubated in the presence of liposomes of different phospholipids, undergo typical modifications: chromatin dispersion and reduction of the interchromatin granules in nuclei incubated with negatively charged liposomes and increase of the chromatin density and of the number and size of the interchromatin granules in nuclei incubated with neutral liposomes. The possibility that the observed modifications are caused by an impairment of the transport and translocation of ribonucleoproteins belonging to the inner nuclear matrix, is suggested by the results obtained by radiotracer techniques on the release of RNA from liposome‐incubated nuclei.
The relation between inhibition of glycolysis and stimulation of oxygen uptake due to glucagon in livers from rats in different metabolic conditions
Authors: Bazotte R. B. , Constantin J. , Hell N. S. , Iwamoto E. L. Ishii , Bracht A. 
Published: May 2005

AbstractThe relation between the effects of glucagon on oxygen consumption and glycolysis in livers from rats under different metabolic conditions was examined. Respiration of substrate‐free perfused livers with different glycolytic fluxes, induced by changes in the pattern of food intake, responds differently to the infusion of 1 nM glucagon. The increases in oxygen uptake caused by 1 nM glucagon correlate reasonably well with the absolute decreases in glycolysis. The degree of inhibition of glycolysis is approximately constant (58 per cent) for all metabolic conditions. When no recovery of glycolysis occurs upon cessation of glucagon infusion, the same happens with oxygen consumption, which remains stimulated. It is concluded that in livers with no appreciable biosynthetic activities, the action of glucagon on respiration and glycolysis may be interpreted in terms of an interaction of ‘cytosolic’ and mitochondrial ATP generating processes.
Halothane induced disorder of red cell membranes of subjects susceptible to malignant hyperthermia
Authors: Ohnishi S. Tsuyoshi , Ohnishi Tomoko 
Published: May 2005

AbstractMembrane fluidity of red blood cells drawn from malignant hyperthermic pigs and humans was studied using spin‐probes and electron paramagnetic resonance technique. The order parameter and rotational correlation time were determined with 12–doxylstearate and 16‐doxylstearate, respectively. It was found that halothane decreased both parameters, but that the decrease of these parameters in subjects susceptible to malignant hyperthermia was much greater than that in normal subjects. The differences were most pronounced at 3 mM halothane. A possibility of using blood for a non‐invasive screening for malignant hyperthermia is discussed.
Angiotensin II vascular receptors in fetal and neonatal rats
Authors: Ghiani Pietro , Uva Bianca M. , Mandich Alberta , Masini Maria Angela 
Published: May 2005

AbstractSpecific binding sites for angiotensin II in aorta and renal arteries have been studied in rat fetuses (18th day of pregnancy) and 1‐day‐old newborn rats by binding studies in arterial membranes using [125I] ileu‐5‐angiotensin II. One type of angiotensin receptor was found both in fetuses and in the newborns; the capacity of this (RT) decreased immediately after birth (from 0·06 ± 0·01 nM to 0·02 ± 0·005 nM; ± SEM) and the affinity (Kd) increased at birth (from 3·5 ± 0·6 nM to 19·5 ± 1·2 nM; ± SEM). Localization of the specific binding sites was studied by autoradiography on arteries from fetal and newborn rats either perfused with iodinated angiotensin II by cannulation of the aorta or in vitro on cryostat sections incubated with the radioactive angiotensin II. Both in fetuses and in the newborn the binding sites were located in the tunica media of the arteries.
Isolation and characterization of parenchymal cells from experimentally induced macronodular rat liver cirrhosis
Authors: Müller Diethard , Franke Hans , Zimmermann Thomas , Dargel Rolf 
Published: May 2005

AbstractHepatocytes were isolated from thioacetamide (TAA)‐induced macronodular cirrhotic rat livers by a collagenase perfusion method. In the content of cellular metabolites, fatty acid uptake and lipid secretion there were no substantial differences compared with cells isolated from micronodular cirrhosis described previously. In contrast to isolated hepatocytes from normal livers those from macronodular cirrhosis had a lowered cellular content of triglycerides, phospholipids and cholesterol but not of cholesterol esters and free fatty acids. In macronodular cirrhosis hepatocytes of hypertrophic type, rich in cell organelles, can be distinguished ultrastructurally from those with signs of atrophy and degeneration. Immediately after isolation many hepatocytes isolated from macronodular cirrhosis showed plasma membrane blebbing. Whereas the blebbing was without recognizable effects on the fine structure of the isolated hepatocytes of the hypertrophic type, in the more atrophic ones some mitochondria were swollen. In addition, morphological analysis of the crude and purified suspensions revealed a partial selection of the hypertrophic cells during the isolation procedure, presumably due to a more labile state of those cells which showed signs of atrophy and degeneration. When stabilized in the suspension medium, however, the hepatocytes maintained complex metabolic functions for at least 2 h. Thus, the method described allows the isolation of parenchymal cells from TAA‐induced macronodular cirrhotic livers for studying ultrastructural and biochemical alterations in hyperregenerative experimental liver cirrhosis.
A polyclonal antiserum against the rabbit progesterone receptor recognizes the human receptor: Immunohistochemical localization in rabbit and human uterus
Authors: Zaino Richard J. , Feil Peter D. , Clarke Christine L. , Mortel Rodrigue , Satyaswaroop Pondichery G. 
Published: May 2005

AbstractA polyclonal antiserum, raised in guinea pigs immunized with the 116 000 Mr rabbit uterine progesterone receptor (PR), was used to demonstrate immunoreactive PR in frozen fixed sections of rabbit and human uterus. In both species, PR localization was exclusively nuclear. For the rabbit uterus, staining intensity was greatest in the myometrium, followed by endometrial stroma, glands, and luminal epithelium. In premenopausal human endometrium and myometrium there was intense staining of nuclei from proliferative phase glands and myometrium. In the secretory phase the glands failed to stain, yet immunostaining persisted in the myometrium.