Josep Centelles - Academia.edu (original) (raw)

Papers by Josep Centelles

General Pharmacology: The Vascular System, 1988

Extracellular degradation of adenosine by adenosine deaminase was studied in the rat duodenum usi... more Extracellular degradation of adenosine by adenosine deaminase was studied in the rat duodenum using high performance liquid chromatography (HPLC) and pharmacological techniques. 2. Relaxant responses to adenosine (1-10 pM) were potentiated in a concentration-dependent manner by erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and deoxycoformycin, both of which are inhibitors of adenosine deaminase. 3. Breakdown of adenosine, determined by HPLC, due to incubation with segments of rat duodenum was inhibited by both EHNA and deoxycoformycin. Cytosolic sources of adenosine deaminase were excluded. 4. Relaxant responses to adenosine were also potentiated by the adenosine transport inhibitor dilazep, which did not inhibit adenosine deaminase activity. 5. The extracellular adenosine deaminase activity (4 units/g tissue) was high compared with activity previously determined in other organs.

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1987

The level of adenosine deaminase in various rat tissues has been tested. 2. The enzyme activity o... more The level of adenosine deaminase in various rat tissues has been tested. 2. The enzyme activity of cytosolic fractions decreased in the following order: lung > spleen > small intestine > stomach > kidney > heart > liver > skeletal muscle > forebrain > cerebellum. 3. The enzyme had identical patterns from tissue to tissue with respect to Km, V, and K~ values for ethanol and for dimethyl sulfoxide, with respect to electrophoretic behaviour and to inhibition by antibodies anti-rat brain adenosine deaminase.

Metallomics, 2014

Cisplatin is a platinum-based compound that acts as an alkylating agent and is used to treat a va... more Cisplatin is a platinum-based compound that acts as an alkylating agent and is used to treat a variety of malignant tumors including lung cancer. As cisplatin has significant limitations in the clinic, alternative platinum compounds such as cycloplatinated complexes have been considered as attractive anti-tumor agents. Here, we report the antiproliferative activity of a novel diastereomerically pure cycloplatinated complex (Sp,1S,2R)-[Pt{(κ(2)-C,N)[(η(5)-C5H3)-CH[double bond, length as m-dash]N-CH(Me)-CH(OH)-C6H5]Fe(η(5)-C5H5)}Cl(DMSO)] 6a, against A549 non-small cell lung cancer. Mechanistic studies revealed that compound 6a induces nuclear translocation of a FOXO3a reporter protein as well as endogenous FOXO3a in U2OS and A549 cells, respectively. Accordingly, treatment of A549 cells with compound 6a activates the intrinsic caspase pathway and dramatically increases the percentage of apoptotic cells. Furthermore, 6a displays a synergistic antiproliferative effect when applied together with cisplatin. Compound 6a is also active in other cancer cell lines including NCI-H460 large cell lung cancer cells. Importantly, antiproliferative activity of the platinacycle 6a on the non-tumor and non-proliferating 3T3-L1 cell line is weaker than in all cancer cell lines tested.

Journal of Neurochemistry, 2002

EAAC1-mediated glutamate transport concentrates glutamate across plasma membranes of brain neuron... more EAAC1-mediated glutamate transport concentrates glutamate across plasma membranes of brain neurons and epithelia. In brain, EAAC1 provides a presynaptic uptake mechanism to terminate the excitatory action of released glutamate and to keep its extracellular concentration below toxic levels. Here we report the effect of well known anxiolytic compounds, benzodiazepines, on glutamate transport in EAAC1-stably transfected Chinese hamster ovary (CHO) cells and in EAAC1-expressing Xenopus laevis oocytes. Functional properties of EAAC1 agreed well with already reported characteristics of the neuronal high-affinity glutamate transporter (K m D-Asp,CHO cells: 2.23 Ϯ 0.15 M; K m D-Asp,oocytes: 17.01 Ϯ 3.42 M). In both expression systems, low drug concentrations (10-100 M) activated substrate uptake (up to 200% of control), whereas concentrations in the millimolar range inhibited (up to 50%). Furthermore, the activation was more pronounced at low substrate concentrations (1 M), and the inhibition was attenuated. The activity of other sodium cotransporters such as the sodium/D-glucose cotransporter SGLT1, stably transfected in CHO cells, was not affected by benzodiazepines. In electrophysiological studies, these drugs also failed to change the membrane potential of EAAC1expressing Xenopus laevis oocytes. These results suggest a direct action on the glutamate transporter itself without modifying the general driving forces. Thus, in vivo low concentrations of benzodiazepines may reduce synaptic glutamate concentrations by increased uptake, providing an additional mechanism to modulate neuronal excitability.

Journal of Chemical Education, 2005

Molecular Brain Research, 2001

Nitric oxide synthases (NOS) are heme-containing enzymes which catalyse the oxidation of L-argini... more Nitric oxide synthases (NOS) are heme-containing enzymes which catalyse the oxidation of L-arginine to nitric oxide and L-citrulline. Some nitrogenated compounds have been reported to coordinate with the iron atom from the heme group, thus inhibiting NOS. 1,4-Benzodiazepines are nitrogenated compounds which have many physiological effects such as antianxiety, antiepileptic, hypnotic, and muscle relaxation properties. The aim of this paper was to measure the effect of different benzodiazepines on NOS activity in pig brain extracts. Medazepam, pinazepam, diazepam, oxazepam and alprazolam competitively inhibited NOS with IC in the micromolar range. 50 Other benzodiazepines showed no effect at concentrations as high as 200 mM. Due to the structural similarity of the benzodiazepine ring nucleus with L-arginine, we propose a benzodiazepine-enzyme interaction to explain the competitive inhibitions. By comparing benzodiazepine effects and their structures, the inhibitory effect of benzodiazepines on NOS is related to the absence of substituents on N4 and to the absence of a halogen substituent on C5 phenyl group. Although benzodiazepine's inhibitions observed in this study are not in the physiological range in normal cases, these inhibitions could be significant in drug abuse situations and should be taken into account for the rational design of drugs which specifically inhibit NOS.

Biochimica et Biophysica Acta (BBA) - Biomembranes, 1991

Energetic coupling in Na.linked glucose transport in renal brush border membrane vesicles has bee... more Energetic coupling in Na.linked glucose transport in renal brush border membrane vesicles has been studied in terms of various carrier models differing with respect to reaction order (random vs. ordered), and to rate limitation of steps within the mutes of carrier-mediated solute transfer (translation across the membrane barrier vs. binding/release between carrier and hulk solution). (2) By computer simulation it was found that effective energetic coupling requires the leakage routes to be s!gniflcaufly, if not predominantly, rate-limlted by their (barrier.crossing) translatory steps. This does nat apply to the transfer route of Ihe ternary complex, as ¢oul~ing is possible whether or not this route is rate-limited by the translatory step. (3) The system transports ~ in the absence of Na + (unipoct) and the unidirectional flux is stimulated by unlabeled gl~mee on the tram side 0~lative tracer coupling). It Is concluded that glucose binds to the carrier on either side witlMm Na, as wukl be camhteat with either a random system or one mode of ordered system with mirror symmetry ~ binds before Nu) l~t inconsistent with either mode of glide symmetry. The tracer coupling appears to iadkate tiutt the rate ¢edlkimt of carrler-medlated glucose transfer exeeeds that of the empty carrier. (4) The Na-liL_lu~l zero-Warn flow of glucese in either direction is strongly trans-inhibited by Na. This consistent with a random system in wlhieh Nu bleclm or retards the transloeation of the glucose.free carrier, thereby reducing 'siil~inli' thrmqll an lateral lealka~ route. It is also consistent with the above memioaed ecdered system, (i.e., in tin ~ of Nlt-lramport withe~ e-glucose) if it is assumed that trams Na interferes with tbe dissociation of the ternary eaml~X, tlmreby ~ release of glucose. (S) Minimum equmbrium exchange of glucose is stimulated ht the presmee of Nit. "Ibis appears to indicate that Na expands the flow density of carrler-mediated glucose transfer. Tlds expansion does nat result from a 'velocity effect' (the ternary complex moving faster than the binary glucose carrier complex), as Na fails to stimulate maximum equilibrium exdtange. It can instead be accounted for by mt 'alBai~ effect' (the afflalty of the carrier for glucose being increased by Na) as Na de~esses the Michaetis constant of~m exekllal~ (6) The data support the assumption that energetk tmepling iu a random system of Na-lialkd ~ mmsl~rt is Ix~qllbt about by two kinds of effects: (a) Obslm¢lion of the ~uternal leakage mute tlmmgb the glucose-free Na-¢anter complex (slipping), or (b) by exlMnsiea of the flow of the ternary Nn-glmmN-~rri~ eem[~m by positive eee[x, rativity. In tbe specified ordered system, tbe two effects reduce to one, as ~ ~ result from ~ failure of Na to bind to the glneose-free (eml~) carrier. (7) Whereas the random model is camistmt with all experimental observations, the ordered system appears to be inconsistent with some observadom, and ~ ~ athers only under improbable assumptions, for instance that the final release of glucose be slow enoulb to limit qhe overall transport rate. Though a rigerous proof may still be missing, the presented evidmee appears to stroa~ favor the random.model. (8) Kinetic data alone do not tell to whkh extent any of the transfer routes Js rate-limited by (barrier.crossing) translatory (T) steps and by binding/release (B) steps. It can be sbowu themetkully, bowever, that effective energetic coupling requires the leakage routes, i.e., those with eltber glucose alone or Nn alone, to be signilicantly, if not predominantly rate-limited by their (barrier-crossing) tramlutory (T) steps, it is plausible, but cannot be fully ascertained yet, that this also applies to the (transport-efl~tive) transfer route of the ternary complex.

Biochimica et Biophysica Acta (BBA) - Biomembranes, 1990

Analytical Letters, 2003

The present article describes a new method for determining nitrite. The method is based on the re... more The present article describes a new method for determining nitrite. The method is based on the reaction of 1,2-diaminoanthraquinone (DAQ) to form a colorless anthraquinone triazole. Absorbance was seen to change linearly with increasing nitrite concentrations in the (0.05–50 µM) range. In order to test the potential use of this method for the determination of nitric oxide synthase (NOS) activity, a panel of enzyme substrates (NADPH), cofactors (FMNH2, FADH2), reductants (DTT), and exogenous proteins were tested as potentially interfering substances. Under the experimental conditions used no single compound among those tested interfered in the assay. This is a clear advantage with respect to the Griess method, which shows interferences with NADPH, but more especially with respect to the DAN method, which presents interferences with NADPH, FMNH2, FADH2, and hemoglobin. Nevertheless, 1,2-diaminoanthraquinone is less water-soluble than DAN and the Griess reagent, making the use of this substrate difficult in the determination of nitric oxide synthase activity in biological samples. We propose to use this method for nonbiological samples or for environmental analysis.

The Journal of Immunology

The expression of surface adenosine deaminase (ADA) and CD26 in activated human T cells was studi... more The expression of surface adenosine deaminase (ADA) and CD26 in activated human T cells was studied by flow cytometry. PBLs and CD3+ or CD4+ cells, when subjected to a variety of stimuli (anti-CD3 Abs plus IL-2 or phorbol esters), presented two structurally different cell populations, which differed in size and cellular complexity (populations B1 and B2). In PBLs triggered by an anti-CD3 mAb there was no significant increase of expression of either surface ADA or CD26 in cells of population B1, whose structure is similar to that of nonstimulated cells. In contrast, there was a significant increase in the percentage of expression of ADA and CD26 in the population B2, which corresponds to structurally more complex and larger cells. In the case of activation via TCR-CD3 but in the presence of IL-2 or via phorbol esters, the increase was found in cells from both populations, but B2 cells always showed a higher percentage of expression than B1 cells. The results of increased expression o...

Text S3.pdf. An example of standard deviations in a series of technical and biological replicates... more Text S3.pdf. An example of standard deviations in a series of technical and biological replicates. (PDF 65Â kb)

Text S2.pdf. Proposed fragment, which overlap with glutamate C2-C4 in GC/MS spectra. (PDF 926Â kb)

Text S1.pdf. Calculation of natural 13C distribution. (PDF 58Â kb)

International Journal on Engineering, Science and Technology, 2022

Games are excellent teaching tools for self-learning. Students playing a game enjoy themselves an... more Games are excellent teaching tools for self-learning. Students playing a game enjoy themselves and at the same time learn basic and important concepts. Different games including crossword puzzles, word search puzzles, knight’s tour games, connecting dots, mazes, matching two sets, amidakuji, and logic games were used for continuous assessment during the confinement due to pandemic. These games were developed as part of the GINDO-UB180 teaching innovation group activities. Since these games were very successful, we decided to combine all of them and construct a new teaching activity, that would help our students to study one essential metabolic pathway: The Krebs cycle. This activity (https://forms.gle/BPvpnLQRNYNPxcLQ7) is an Escape-room, and it was recently tested by our students in a General Biochemistry course. The code of the Escape room after the game is a word: either the longest in the letter soup, an anagram from several boxes from the crossword puzzles, the sentence from th...

Frontiers in Molecular Biosciences, 2017

Rhabdomyolysis is a disorder characterized by acute damage of the sarcolemma of the skeletal musc... more Rhabdomyolysis is a disorder characterized by acute damage of the sarcolemma of the skeletal muscle leading to release of potentially toxic muscle cell components into the circulation, most notably creatine phosphokinase (CK) and myoglobulin, and is frequently accompanied by myoglobinuria. In the present work, we evaluated the toxicity of p-phenylenediamine (PPD), a main component of hair dyes which is reported to induce rhabdomyolysis. We studied the metabolic effect of this compound in vivo with Wistar rats and in vitro with C2C12 muscle cells. To this aim we have combined multi-omic experimental measurements with computational approaches using model-driven methods. The integrative study presented here has unveiled the metabolic disorders associated to PPD exposure that may underlay the aberrant metabolism observed in rhabdomyolys disease. Animals treated with lower doses of PPD (10 and 20 mg/kg) showed depressed activity and myoglobinuria after 10 h of treatment. We measured the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine kinase (CK) in rats after 24, 48, and 72 h of PPD exposure. At all times, treatment with PPD at higher doses (40 and 60 mg/kg) showed an increase of AST and ALT, and also an increase of lactate dehydrogenase (LDH) and CK after 24 h. Blood packed cell volume and hemoglobin levels, as well as organs weight at 48 and 72 h, were also measured. No significant differences were observed in these parameters under any condition. PPD induce cell cycle arrest in S phase and apoptosis (40% or early apoptotic cells) on mus musculus mouse C2C12 cells after 24 h of treatment. Incubation of mus musculus mouse C2C12 cells with [1,2-13 C 2 ]-glucose during 24 h, subsequent quantification of 13 C isotopologues distribution in key metabolites of glucose metabolic network and a computational fluxomic analysis using in-house developed software (Isodyn) showed that PPD is inhibiting glycolysis, non-oxidative pentose phosphate pathway, glycogen turnover, and ATPAse reaction leading to a reduction in ATP synthesis. These findings unveil the glucose metabolism collapse, which is consistent with a Marín de Mas et al. PPD Metabolic Toxicity in Muscle decrease in cell viability observed in PPD-treated C2C12 cells and with the myoglubinuria and other effects observed in Wistar Rats treated with PPD. These findings shed new light on muscle dysfunction associated to PPD exposure, opening new avenues for cost-effective therapies in Rhabdomyolysis disease.

BMC bioinformatics, Jan 3, 2017

Tracing stable isotopes, such as (13)C using various mass spectrometry (MS) methods provides a va... more Tracing stable isotopes, such as (13)C using various mass spectrometry (MS) methods provides a valuable information necessary for the study of biochemical processes in cells. However, extracting such information requires special care, such as a correction for naturally occurring isotopes, or overlapping mass spectra of various components of the cell culture medium. Developing a method for a correction of overlapping peaks is the primary objective of this study. Our computer program-MIDcor (free at https://github.com/seliv55/mid_correct) written in the R programming language, corrects the raw MS spectra both for the naturally occurring isotopes and for the overlapping of peaks corresponding to various substances. To this end, the mass spectra of unlabeled metabolites measured in two media are necessary: in a minimal medium containing only derivatized metabolites and chemicals for derivatization, and in a complete cell incubated medium. The MIDcor program calculates the difference (D)...

Journal of Translational Science, 2016

Excitatory aminoacids (EAAs) are stored in glutamatergic neurons and related into synaptic cleft,... more Excitatory aminoacids (EAAs) are stored in glutamatergic neurons and related into synaptic cleft, where they can activate inotropic or metabotropic receptors. Their action ends due to transport mechanisms performed by EAAT transporters (EAAT1/GLAST, EAAT2/GLT1, EAAT3/EAAC1, and EAAT4 or EAAT5). Glutamate neurotoxicity has been described in several neurodegenerative diseases such as Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD) and amyotropic lateral sclerosis ALS). Some drugs, such as paclitaxel, are able to increase translation of microRNA and could be possible used as regulatory against glutamate neurotoxicity.

Biochemical Journal, 1992

1. A model is presented for adenosine transport and metabolism in different steady states. The mo... more 1. A model is presented for adenosine transport and metabolism in different steady states. The model considers steady-state equations for metabolic enzymes based on information from the literature on their kinetic behaviour. 2. Assuming that extracellular adenosine and inosine are translocated by three transporters, we have devised rate equations for these nucleoside transporters which are valid when both nucleosides are present. Since the Na(+)-independent transporter can either incorporate nucleosides into the cell or release them, various conditions have been simulated in which inosine was either incorporated or released. 3. Control analyses are reported which show that the fluxes towards intracellular adenine nucleosides are controlled by ecto-5′-nucleotidase in some circumstances and by the nucleoside transporters in others. The nucleoside transporter is responsible for five fluxes (two Na+ dependent adenosine transport mechanisms, a Na(+)-dependent inosine transport, a Na(+)-i...

Technological and Medical Implications of Metabolic Control Analysis, 2000

... MARTA CASCANTE1, BEGONA COMIN1,JOAN BOREN1, BADR RA&#x27;is1, JOSEP J. CENTELLES1, JO... more ... MARTA CASCANTE1, BEGONA COMIN1,JOAN BOREN1, BADR RA&#x27;is1, JOSEP J. CENTELLES1, JOAQ...U1M PUIGJANER1, WAI-NANG PAUL LEE2 AND LASZLO G ... hand, for an enzyme with a control coefficient of 0.01, the flux would be reduced only by 1% for the same 50 ...

Journal of Biosciences and Medicines, 2014

This paper compares the irreversible and reversible rate equations from several uni-uni kinetic m... more This paper compares the irreversible and reversible rate equations from several uni-uni kinetic mechanisms (Michaelis-Menten, Hill and Adair equations) and bi-bi mechanisms (single-and doubledisplacement equations). In reversible reactions, Haldane relationship is considered to be identical for all mechanisms considered and reversible equations can be also obtained from this relationship. Some reversible reactions of the metabolism are also presented, with their equilibrium constant.