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Bustamante M, Díaz F, Muñoz M, Gross HJ, Rivas CI, Llancaqueo A, Núñez L, Campos L, Kirsten L, Grandón J, González M, Barra V, Vera JC, Bachem MG. Oxidized low density lipoproteins induce apoptosis in human lymphocytes: involvement of mitogen-activated protein kinases. Cell Mol Biol (Noisy-le-grand) 2007; 53 Suppl:OL954-64. [PMID: 17695085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Oxidized low density lipoproteins (oxLDL), macrophages and T-lymphocytes are present in atherosclerotic lesions. We and others have shown that oxLDL is cytotoxic for macrophages, endothelial, smooth muscle and activated T-lymphocytes and induce apoptosis. Here we demonstrate that (i) oxidized LDL (oxLDL), oxidized VLDL (oxVLDL) and hydrogen peroxide (H2O2) induce apoptosis in human T-lymphocytes and (ii) mitogen-activated protein kinases are involved in this process. Apoptosis was monitored by immunofluorescence microscopy and flow cytometry for annexin V binding, Apo 2.7 expression, the TUNEL reaction and caspase 3 activity. In the presence of oxLDL (100 microg/ml), oxVLDL (50 microg/ml) and H2O2 (5 mM), the fraction of apoptotic cells increased within 6 hours to more than 70%. Preincubation of lymphocytes with the MAPKK inhibitor PD-98059 and the p38MAPK inhibitor SB-203580 almost completely abolished these effects. Furthermore, oxLDL and H2O2 but not native LDL strongly enhanced phosphorylation of JNK, p38MAPK and p42/44MAPK. The results suggest that in the resting lymphocyte apoptosis triggered by oxidized lipoproteins and oxidative stress depends on the activation of p44/42MAPK and p38MAPK cascades.
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Núñez L, del Mar Espinosa M, Embid M, Luis Muñiz J. 314 A TLD mailed dosimetry system for QC in small beam Radiotherapy. Radiother Oncol 2005. [DOI: 10.1016/s0167-8140(05)81290-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pujadas M, Núñez L, Plaza J, Bezares JC, Fernández JM. Comparison between experimental and calculated vehicle idle emission factors for Madrid fleet. THE SCIENCE OF THE TOTAL ENVIRONMENT 2004; 334-335:133-140. [PMID: 15504499 DOI: 10.1016/j.scitotenv.2004.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/01/2004] [Indexed: 05/24/2023]
Abstract
Experimental vehicle idle emission factors have been compared with calculated factors for 100 vehicles in Madrid. The vehicles were selected according to the distribution (by age and fuel type) of the official, national car fleet (up to 31 December 1997). They were then clustered following the criteria of the Computer Programme to Calculate Emissions from Road Transport (COPERT III) category classification. NO(x) and CO idle emission factors show a wide range of values in each category and an important deviation between the experimental values and the corresponding parameterised ones. Fifteen percent of tested vehicles in this study have been identified as gross emitters generating approximately 50% of the total CO emission volume.
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Sánchez-Doblado F, Andreo P, Capote R, Leal A, Perucha M, Arráns R, Núñez L, Mainegra E, Lagares JI, Carrasco E. Ionization chamber dosimetry of small photon fields: a Monte Carlo study on stopping-power ratios for radiosurgery and IMRT beams. Phys Med Biol 2003; 48:2081-99. [PMID: 12894972 DOI: 10.1088/0031-9155/48/14/304] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Absolute dosimetry with ionization chambers of the narrow photon fields used in stereotactic techniques and IMRT beamlets is constrained by lack of electron equilibrium in the radiation field. It is questionable that stopping-power ratio in dosimetry protocols, obtained for broad photon beams and quasi-electron equilibrium conditions, can be used in the dosimetry of narrow fields while keeping the uncertainty at the same level as for the broad beams used in accelerator calibrations. Monte Carlo simulations have been performed for two 6 MV clinical accelerators (Elekta SL-18 and Siemens Mevatron Primus), equipped with radiosurgery applicators and MLC. Narrow circular and Z-shaped on-axis and off-axis fields, as well as broad IMRT configured beams, have been simulated together with reference 10 x 10 cm2 beams. Phase-space data have been used to generate 3D dose distributions which have been compared satisfactorily with experimental profiles (ion chamber, diodes and film). Photon and electron spectra at various depths in water have been calculated, followed by Spencer-Attix (delta = 10 keV) stopping-power ratio calculations which have been compared to those used in the IAEA TRS-398 code of practice. For water/air and PMMA/air stopping-power ratios, agreements within 0.1% have been obtained for the 10 x 10 cm2 fields. For radiosurgery applicators and narrow MLC beams, the calculated s(w,air) values agree with the reference within +/-0.3%, well within the estimated standard uncertainty of the reference stopping-power ratios (0.5%). Ionization chamber dosimetry of narrow beams at the photon qualities used in this work (6 MV) can therefore be based on stopping-power ratios data in dosimetry protocols. For a modulated 6 MV broad beam used in clinical IMRT, s(w,air) agrees within 0.1% with the value for 10 x 10 cm2, confirming that at low energies IMRT absolute dosimetry can also be based on data for open reference fields. At higher energies (24 MV) the difference in s(w,air) was up to 1.1%, indicating that the use of protocol data for narrow beams in such cases is less accurate than at low energies, and detailed calculations of the dosimetry parameters involved should be performed if similar accuracy to that of 6 MV is sought.
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Núñez L, Cubiella J, Moreno C, Díez MS, Sánchez E, Vega M. Retinopatía de Purtscher: complicación infrecuente de la pancreatitis aguda no alcohólica. GASTROENTEROLOGIA Y HEPATOLOGIA 2003; 26:541-4. [PMID: 14642240 DOI: 10.1016/s0210-5705(03)70409-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Purtscher's retinopathy is a rare complication of acute alcoholic pancreatitis that is characterized by the development of cotton-wool exudates and retinal hemorrhages located around the optic disk. Its development is due to ischemic phenomena in the posterior pole of the retina due to microemboli in the retinal arterioles and capillaries. This complication is not related to a poorer prognosis of acute pancreatitis and the retinopathy usually has a favorable outcome with disappearance of the ophthalmic lesions and restoration of visual acuity after 4-6 weeks in most cases. However, some patients may show residual lesions, especially if optical atrophy occurs. We present a 40-year-old woman with loss of visual acuity due to Purtscher's retinopathy during the course of mild acute idiopathic pancreatitis.
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Villalobos C, Núñez L, Chamero P, Alonso MT, García-Sancho J. Mitochondrial [Ca(2+)] oscillations driven by local high [Ca(2+)] domains generated by spontaneous electric activity. J Biol Chem 2001; 276:40293-7. [PMID: 11668185 DOI: 10.1074/jbc.c100465200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria take up calcium during cell activation thus shaping Ca(2+) signaling and exocytosis. In turn, Ca(2+) uptake by mitochondria increases respiration and ATP synthesis. Targeted aequorins are excellent Ca(2+) probes for subcellular analysis, but single-cell imaging has proven difficult. Here we combine virus-based expression of targeted aequorins with photon-counting imaging to resolve dynamics of the cytosolic, mitochondrial, and nuclear Ca(2+) signals at the single-cell level in anterior pituitary cells. These cells exhibit spontaneous electric activity and cytosolic Ca(2+) oscillations that are responsible for basal secretion of pituitary hormones and are modulated by hypophysiotrophic factors. Aequorin reported spontaneous [Ca(2+)] oscillations in all the three compartments, bulk cytosol, nucleus, and mitochondria. Interestingly, a fraction of mitochondria underwent much larger [Ca(2+)] oscillations, which were driven by local high [Ca(2+)] domains generated by the spontaneous electric activity. These oscillations were large enough to stimulate respiration, providing the basis for local tune-up of mitochondrial function by the Ca(2+) signal.
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Alarcón P, Núñez L, García-Sancho J. Direct actions of adrenergic agents on rat anterior pituitary cells. Pflugers Arch 2001; 442:834-41. [PMID: 11680615 DOI: 10.1007/s004240100622] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We studied the effects of adrenergic agents on the five main cell types of the rat anterior pituitary by monitoring the changes of the cytosolic free [Ca2+] ([Ca2+]i) in single cells that were identified by multiple sequential primary immunocytochemistry at the end of the Ca2+ measurements. Adrenaline (100 nM) increased [Ca2+]i in 30% of the cells. Responses were most prominent in somatotrophs and corticotrophs (40-65% of the cells responded) whereas the other three cell types, lactotrophs, thyrotrophs and gonadotrophs, gave poorer responses. Selective agonists and antagonists revealed the presence of both alpha1- and beta-adrenergic receptors. Alpha1-receptors dominated in corticotrophs, beta-receptors in somatotrophs. The alpha1-adrenergic responses increased with culture of the cells. The beta-adrenergic responses were mediated by cAMP and consisted of stimulation of Ca2+ entry through L-type voltage-gated channels. Stimulation of alpha1-receptors released Ca2+ from intracellular stores in corticotrophs and induced cAMP-independent Ca2+ entry in somatotrophs. The effects of alpha1-agonists were additive with those of the releasing factors growth hormone-releasing hormone (GHRH) and corticotropin releasing factor (CRF) whereas those of the beta-agonists were not. Our results suggest that direct effects of plasma catecholamines on AP cells may contribute to the hormonal response to stress.
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Núñez L, Fraga F, Castro A, Núñez M, Villanueva M. TTT cure diagram for an epoxy system diglycidyl ether of bisphenol A/1,2 diamine cyclohexane/calcium carbonate filler. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00712-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Nogales-Gaete J, Núñez L, Arriagada C, Sáez D, Figueroa T, Fernández R, González J, Aragón A, Barrientos N, Varas P, Troncoso B, Cárcamo C, Chávez M, Gumucio M, Holmgrenn P, Beltrán G, San Martín E, Manríquez E, Figueroa C. [Clinical characterization of 450 patients with cerebrovascular disease admitted to a public hospital during 1997]. Rev Med Chil 2000; 128:1227-36. [PMID: 11347510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND In Chile, cerebrovascular diseases are the fifth cause of death among men and the third cause among women. AIM To assess the clinical features and management of patients with cerebrovascular disease admitted to a public hospital during 1997. PATIENTS AND METHODS A retrospective analysis of clinical records of patients discharged with a diagnosis of cerebrovascular disease. Those records in which there was discordance between the discharge diagnosis and the clinical picture were not considered in the analysis. RESULTS Of the 563 discharges from the hospital with the diagnosis of cerebrovascular disease, 487 records were located and 450 were considered in the analysis. Fifty four percent of patients were male and ages ranged from 17 to 96 years old. Fifty-one percent of patients had an ischemic stroke, 34% a cerebral hemorrhage, 12% a subarachnoidal hemorrhage and 3% a transient ischemic attack. There was a history of hypertension in 64% patients and 20% had an adequate treatment. Eighteen percent were diabetics, 34% had a heart disease and 20% had a previous episode of stroke. Mean hospital stay was 6.3 days in the emergency room and 11 days in the neurology ward. Hospital infections appeared in 21% of patients (respiratory in 68% and urinary in 22%), lethality was 30.5% and a CAT scan was done in 94%. At the moment of admission, 10% of patients had an evolution of less than 2 hours, 27% had an evolution between 2 and 6 hours and nine cases were potential eligible for thrombolysis. CONCLUSION This is a picture of the local features of patients with cerebrovascular diseases that can be used as a reference for future studies.
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Núñez L, Villalobos C, Boockfor FR, Frawley LS. The relationship between pulsatile secretion and calcium dynamics in single, living gonadotropin-releasing hormone neurons. Endocrinology 2000; 141:2012-7. [PMID: 10830284 DOI: 10.1210/endo.141.6.7491] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well established that pulsatile release of GnRH regulates the reproductive axis, but little is known about the mechanisms underlying this pulsatility. Recent findings that GT1 cells, a line derived from the mouse embryonic hypothalamus, release GnRH in a pulsatile manner indicates that this rhythmic activity is an intrinsic property of GnRH neurons. In several attempts to uncover the intracellular basis for this pulsatile phenomenon, it was revealed that intracellular calcium concentrations change in a rhythmic fashion in GnRH neurons and that cellular depolarization, which triggers a secretory event, is associated with profound calcium changes in the cells. These findings raised the intriguing possibility that periodic alterations in intracellular calcium concentrations may underlie the phenomenon of pulsatile secretion in GnRH neurons. To address this, we first adapted the use of FM1-43 fluorescence to monitor changes of secretion in individual GT1-7 cells and then combined this approach with simultaneous measurement ofintracellular free calcium ([Ca2+]i, fura 2 method). In initial validation experiments, we found that stimulation of exocytosis with K+ (75 mM) or N-methyl-D-aspartate (NMDA, 100 microM) predictably evoked dynamic increases of both FM1-43 and fura 2 fluorescence. Later measurement of calcium dynamics and exocytotic activity in unstimulated cells revealed that [Ca2+]i underwent transitions from quiescence to high oscillatory behavior, and that these shifts were frequently associated with exocytotic events. Moreover, these calcium oscillatory transitions and associated changes in secretory activity occurred synchronously among most adjacent cells and at a frequency similar to that reported for pulsatile release of GnRH by entire cultures of GnRH neurons. Taken together, these results indicate that the intrinsic secretory pulsatility of GnRH neurons appears to be a consequence of coordinated, periodic changes in the pattern of calcium oscillations within individual cells.
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Rosell R, Calvo R, Sánchez JJ, Maurel J, Guillot M, Monzó M, Núñez L, Barnadas A. Genetic susceptibility associated with rare HRAS1 variable number of tandem repeats alleles in Spanish non-small cell lung cancer patients. Clin Cancer Res 1999; 5:1849-54. [PMID: 10430091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The highly polymorphic HRAS1 variable number of tandem repeats (VNTR), which maps 1 kb downstream from the human H-ras1 gene, has been described as an inherited predisposing factor in many human cancers. Here, we investigated the association between the presence of rare HRAS1 minisatellite alleles and lung cancer in the population studied. Four hundred sixty-six HRAS1 VNTR alleles from 233 lung cancer patients and 892 alleles from 446 unaffected controls were typed using PCR-long agarose gel electrophoresis assay of peripheral blood lymphocyte DNA. Rare alleles were differentiated from common alleles (a1, a2, a3, and a4) by shifts in electrophoretic mobility. Odds ratio was calculated to evaluate increased risk of lung cancer associated to the presence of rare HRAS1 alleles. A higher percentage of rare HRAS1 VNTR alleles in lung cancer patients than in unaffected controls (32.7 versus 21.9%) was confirmed. The presence of rare alleles was associated with an increased risk of lung cancer (odds ratio = 1.68; P < or = 0.0001), indicating a genetic predisposition to lung cancer. No differences based on other clinicopathological variables were observed. Furthermore, a meta-analysis showed a higher distribution of rare alleles in our study of Caucasian Spaniards than was found in other studies of American and Northern European Caucasian populations. We conclude that the presence of rare HRAS1 VNTR alleles may be an inherited predisposing factor in lung cancer. This presence can be easily determined from peripheral blood samples by PCR-based methods. Furthermore, interracial variations in allele frequencies and variations between Caucasian subpopulations suggest that genetic variations may be involved in susceptibility to lung oncogenesis, especially in certain ethnic populations.
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Monzó M, Rosell R, Sánchez JJ, Lee JS, O'Brate A, González-Larriba JL, Alberola V, Lorenzo JC, Núñez L, Ro JY, Martín C. Paclitaxel resistance in non-small-cell lung cancer associated with beta-tubulin gene mutations. J Clin Oncol 1999; 17:1786-93. [PMID: 10561216 DOI: 10.1200/jco.1999.17.6.1786] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The mechanisms that cause chemoresistance in non-small-cell lung cancer (NSCLC) patients have yet to be clearly elucidated. Paclitaxel is a tubulin-disrupting agent that binds preferentially to beta-tubulin. Tubulins are guanosine triphosphate (GTP)-binding proteins. Beta-tubulin is a GTPase, whereas alpha-tubulin has no enzyme activity. We reasoned that polymerase chain reaction (PCR) and DNA sequencing of the beta-tubulin gene could reveal more information regarding the connection between beta-tubulin mutations and primary paclitaxel resistance. PATIENTS AND METHODS Constitutional genomic DNA and paired tumor DNA were isolated from 49 biopsies from 43 Spanish and six American stage IIIB and IV NSCLC patients who had been treated with a 3-hour, 210 mg/m(2) paclitaxel infusion and a 24-hour, 200 mg/m(2) infusion, respectively. Oligonucleotides specific to beta-tubulin were designed for PCR amplification and sequencing of GTP- and paclitaxel-binding beta-tubulin domains. RESULTS Of 49 patients with NSCLC, 16 (33%; 95% confidence interval [CI], 20.7% to 45.3%) had beta-tubulin mutations in exons 1 (one patient) or 4 (15 patients). None of the patients with beta-tubulin mutations had an objective response, whereas 13 of 33 (39.4%; 95% CI, 22.8% to 56%; P = 0.01) patients without beta-tubulin mutations had complete or partial responses. Median survival was 3 months for the 16 patients with beta-tubulin mutations and 10 months for the 33 patients without beta-tubulin mutations (P =.0001). CONCLUSION We have identified beta-tubulin gene mutations as a strong predictor of response to the antitubulin drug paclitaxel; these mutations may represent a novel mechanism of resistance and should be examined prospectively in future trials of taxane-based therapy in NSCLC.
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Miquel JF, Núñez L, Amigo L, González S, Raddatz A, Rigotti A, Nervi F. Cholesterol saturation, not proteins or cholecystitis, is critical for crystal formation in human gallbladder bile. Gastroenterology 1998; 114:1016-23. [PMID: 9558292 DOI: 10.1016/s0016-5085(98)70322-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Biliary proteins are promoters of cholesterol crystallization in artificial model bile. However, their pathogenic importance for cholesterol precipitation in native gallbladder bile (GB) is uncertain. The aim of this study was to evaluate the significance of biliary lipids and proteins on cholesterol crystal detection time (ChCDT) of GB in patients with gallstones. METHODS ChCDT and concentrations of lipids, albumin, mucins, aminopeptidase N, alpha1-acid glycoprotein, haptoglobin, and immunoglobulins (Igs) were measured in GB of 92 patients, 52 of whom had cholesterol gallstones. RESULTS ChCDT was markedly reduced in gallstone patients. Compared with patients without gallstones, they had a significant increase in cholesterol saturation and total protein, albumin, mucin, and IgG biliary concentrations. In univariate analysis, ChCDT of GB was significantly correlated with cholesterol saturation and total lipid, protein, Ig, aminopeptidase N, and alpha1-acid glycoprotein concentrations. However, stepwise logistic regression analysis showed that only cholesterol saturation independently correlated to ChCDT. Gallbladder inflammation correlated with the concentration of Igs, but subtraction of IgG from GB did not modify the ChCDT. CONCLUSIONS Biliary cholesterol transport and saturation, but not proteins, appear critical for the cholesterol crystallization abnormality observed in native bile from patients with gallstones.
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Villalobos C, Núñez L, Frawley LS, García-Sancho J, Sánchez A. Multi-responsiveness of single anterior pituitary cells to hypothalamic-releasing hormones: a cellular basis for paradoxical secretion. Proc Natl Acad Sci U S A 1997; 94:14132-7. [PMID: 9391165 PMCID: PMC28445 DOI: 10.1073/pnas.94.25.14132] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The classic view for hypothalamic regulation of anterior pituitary (AP) hormone secretion holds that release of each AP hormone is controlled specifically by a corresponding hypothalamic-releasing hormone (HRH). In this scenario, binding of a given HRH (thyrotropin-, growth hormone-, corticotropin-, and luteinizing hormone-releasing hormones) to specific receptors in its target cell increases the concentration of cytosolic Ca2+ ([Ca2+]i), thereby selectively stimulating the release of the appropriate hormone. However, "paradoxical" responses of AP cells to the four well-established HRHs have been observed repeatedly with both in vivo and in vitro systems, raising the possibility of functional overlap between the different AP cell types. To explore this possibility, we evaluated the effects of HRHs on [Ca2+]i in single AP cells identified immunocytochemically by the hormone they stored. We found that each of the five major AP cell types contained discrete subpopulations that were able to respond to several HRHs. The relative abundance of these multi-responsive cells was 59% for lactotropes, 33% for thyrotropes, and in the range of 47-55% for gonadotropes, corticotropes, and somatotropes. Analysis of prolactin release from single living cells revealed that each of the four HRHs tested were able to induce hormone release from a discrete lactotrope subpopulation, the size of which corresponded closely to that in which [Ca2+]i changes were induced by the same secretagogues. When viewed as a whole, our diverse functional measurements of multi-responsiveness suggest that hypothalamic control of pituitary function is more complicated than previously envisioned. Moreover, they provide a cellular basis for the so-called "paradoxical" behavior of pituitary cells to hypothalamic hypophysiotropic agents.
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Villalobos C, Alonso-Torre SR, Núñez L, García-Sancho J. Functional ATP receptors in rat anterior pituitary cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1963-71. [PMID: 9435502 DOI: 10.1152/ajpcell.1997.273.6.c1963] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of ATP and other nucleotides on the cytosolic Ca2+ concentration ([Ca2+]i) of single immunocytochemically typed anterior pituitary (AP) cells have been studied. ATP increased [Ca2+]i in a large percentage (60-88%) of all five AP cell types: lactotropes, somatotropes, corticotropes, gonadotropes, and thyrotropes. Additivity experiments suggest the presence of at least two different receptors, one accepting both ATP and UTP (U receptor), producing Ca2+ release from the intracellular stores, and the other preferring ATP (A receptor), producing Ca2+ (and Mn2+) entry. The characteristics of the U and A receptors were consistent with those of P2Y2 and P2X2, respectively, and their distribution in the different AP cell types was not homogeneous. The presence of other ATP receptors such P2Y1 or P2X2/P2X3 heteropolymers in a small fraction of the cells cannot be excluded. Thus functional ionophoric P2X receptors, which are typical of neural tissue, are also present in the pituitary gland and could contribute to regulation of the gland's function.
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MESH Headings
- Adenosine Triphosphate/pharmacology
- Animals
- Calcium/metabolism
- Cells, Cultured
- Kinetics
- Male
- Manganese/metabolism
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/physiology
- Pituitary Hormones, Anterior/metabolism
- Rats
- Rats, Wistar
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2X2
- Receptors, Purinergic P2Y2
- Uridine Triphosphate/pharmacology
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Villalobos C, Núñez L, García-Sancho J. Mechanisms for stimulation of rat anterior pituitary cells by arginine and other amino acids. J Physiol 1997; 502 ( Pt 2):421-31. [PMID: 9263921 PMCID: PMC1159560 DOI: 10.1111/j.1469-7793.1997.421bk.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. Arginine and other amino acids are secretagogues for growth hormone and prolactin in the intact animal, but the mechanism of action is unclear. We have studied the effects of amino acids on cytosolic free calcium concentration ([Ca2+]i) in single rat anterior pituitary (AP) cells. Arginine elicited a large increase of [Ca2+]i) in about 40% of all the AP cells, suggesting that amino acids may modulate hormone secretion by acting directly on the pituitary. 2. Cell typing by immunofluorescence of the hormone the cells store showed that the arginine-sensitive cells are distributed uniformly within all the five AP cell types. The arginine-sensitive cells overlapped closely with the subpopulation of cells sensitive to thyrotrophin-releasing hormone. 3. Other cationic as well as several neutral (dipolar) amino acids had the same effect as arginine. The increase of [Ca2+]i was dependent on extracellular Ca2+ and blocked by dihydropyridine, suggesting that it is due to Ca2+ influx through L-type voltage-gated Ca2+ channels. The [Ca2+]i increase was also blocked by removal of extracellular Na+ but not by tetrodotoxin. The substrate specificity for stimulation of AP cells resembled closely that of the amino acid transport system B0+. We propose that electrogenic amino acid influx through this pathway depolarizes the plasma membrane with the subsequent activation of voltage-gated Ca2+ channels and Ca2+ entry. 4. Amino acids also stimulated prolactin secretion in vitro with a similar substrate specificity to that found for the [Ca2+]i increase. Existing data on the stimulation of secretion of other hormones by amino acids suggest that a similar mechanism could apply to other endocrine glands.
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Lomax RB, Michelena P, Núñez L, García-Sancho J, García AG, Montiel C. Different contributions of L- and Q-type Ca2+ channels to Ca2+ signals and secretion in chromaffin cell subtypes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:C476-84. [PMID: 9124290 DOI: 10.1152/ajpcell.1997.272.2.c476] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this study, we investigated the contribution of different subtypes of voltage-dependent Ca2+ channels to changes in cytosolic free Ca2+ ([Ca2+]i) and secretion in noradrenergic and adrenergic bovine chromaffin cells. In single immunocytochemically identified chromaffin cells, [Ca2+]i increased transiently during high K+ depolarization. Furnidipine and BAY K 8644, L-type Ca2+ channel blocker and activator, respectively, affected the [Ca2+]i rise more in noradrenergic than in adrenergic cells. In contrast, the Q-type Ca2+ channel blocker omega-conotoxin MVIIC inhibited the [Ca2+]i rise more in adrenergic cells. omega-Agatoxin IVA (30 nM), which blocks P-type Ca2+ channels, had little effect on the [Ca2+]i signal. The N-type Ca2+ channel blocker omega-conotoxin GVIA similarly inhibited the [Ca2+]i rise in both cell types. The effects of furnidipine, BAY K 8644, and omega-conotoxin MVIIC on K+-evoked norepinephrine and epinephrine release paralleled those effects on [Ca2+]i signals. However, omega-conotoxin GVIA and 30 nM omega-agatoxin IVA did not affect the secretion of either amine. The data suggest that, in the bovine adrenal medulla, the release of epinephrine and norepinephrine are preferentially controlled by Q- and L-type Ca2+ channels, respectively. P- and N-type Ca2+ channels do not seem to control the secretion of either catecholamine.
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Villalobos C, Núñez L, Garcia-Sancho J. Functional glutamate receptors in a subpopulation of anterior pituitary cells. FASEB J 1996; 10:654-60. [PMID: 8621065 DOI: 10.1096/fasebj.10.5.8621065] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have studied the effects of glutamate receptor agonists on the cytosolic Ca2+ concentration ([Ca/+]i) of single rat anterior pituitary (AP) cells. Ionotropic (NMDA and kainate/AMPA) and, to a smaller extent, metabotropic glutamate receptors were both present in all the five AP cell types, defined by the hormone they store. Cells within all the types responded also to thyrotropin-releasing hormone (TRH). Alternative typing by the response to four well-established hypothalamic releasing hormones (HRHs), GHRH, GnRH, CRH, and TRH, was performed. One-third of the cells were not sensitive to any HRH, another third were sensitive to only one HRH, and the last third were sensitive to more than one HRH, frequently to all four. Only the cells responding to TRH showed functional glutamate receptors. Superimposed to the above association, the strongest responses to glutamate were found in the cells responsive to multiple HRHs. These results suggest that glutamate may act, by a nonsynaptic mechanism, as a new releasing factor for one or, like TRH, several AP hormones. Coexpression of glutamate and TRH receptors in the subpopulation of cells responsive to multiple HRHs might have a functional meaning, perhaps related to phenotypic plasticity and long-term regulation of hormone secretion by the anterior pituitary.
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Jiménez C, Núñez L. Glutamate receptors in the developing cochlear ganglion. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 1996; Suppl 1:159S-160S. [PMID: 9087742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Núñez L, Amigo L, Mingrone G, Rigotti A, Puglielli L, Raddatz A, Pimentel F, Greco AV, González S, Garrido J. Biliary aminopeptidase-N and the cholesterol crystallisation defect in cholelithiasis. Gut 1995; 37:422-6. [PMID: 7590442 PMCID: PMC1382827 DOI: 10.1136/gut.37.3.422] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Several biliary proteins have cholesterol crystallisation promoting activity. One of these glycoproteins is aminopeptidase-N, a canalicular ectoenzyme. This study attempted to localise aminopeptidase-N along the biliary tree, to assess its concentration in a series of 98 patients subjected to abdominal surgery, 40 of them without gall stones, and to correlate its concentration with cholesterol crystal formation time of gall bladder bile. Aminopeptidase-N was isolated from purified native biliary vesicles. A specific polyclonal rabbit anti-aminopeptidase-N antibody was prepared for quantitative immunoblotting and for immunolocalisation. Tissue was obtained from liver biopsy specimens and from gall bladders removed at surgery because of gall stone disease. Aminopeptidase-N was immunolocalised to the apical membranes of hepatocytes and to the apical pole of ductular and gall bladder mucosal cells. The nucleation time of gall bladder bile was mean (SD) 4 (3) days in the gall stone group, compared with 21 (18) days in the control group (p < 0.001). Total absolute biliary protein and aminopeptidase-N concentrations were similar in both the control and gall stone patients. There was a reciprocal significant correlation, however, between the nucleation time and the relative aminopeptidase-N concentration (r = -0.35, p < 0.01) only in the gall stone group of patients. This study shows that this apical transmembrane ectoenzyme with cholesterol crystallisation promoting activity is present along the biliary tree and the hepatocyte. These findings support the concept that high concentrations or qualitative changes of biliary aminopeptidase-N contribute to cholesterol gall stone formation.
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Alonso A, Carvalho J, Alonso-Torre SR, Núñez L, Boscá L, Sánchez Crespo M. Nitric oxide synthesis in rat peritoneal macrophages is induced by IgE/DNP complexes and cyclic AMP analogues. Evidence in favor of a common signaling mechanism. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1995; 154:6475-83. [PMID: 7539021 DOI: pmid/7539021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The production of nitric oxide was studied in rat adherent peritoneal cells stimulated with preformed IgE/DNP-BSA complexes made of IgE obtained from a secreting hybridoma. Stimulation with complexes at equivalence induced both the production of NO and an increased expression of the mRNA of the inducible isoform of NO synthase (iNOS). Production of NO was also elicited by a rabbit polyclonal F(ab')2 anti-CD23 cross-reacting with rat CD23. Because IgE/DNP-BSA complexes did not elicit Ca2+ mobilization and genistein did not influence the production of NO, cyclic AMP was considered as an alternative signaling molecule. Combination of a suboptimal concentration of dibutyryl cyclic AMP and IgE/DNP-BSA complexes showed an additive effect on NO production, whereas this was not observed when the agonists were used at supraoptimal doses. The inhibitor of cyclic AMP-specific phosphodiesterase IV, rolipram, which acts on the enzyme isoform predominantly expressed in inflammatory cells, also induced the production of NO. Furthermore, IgE/DNP-BSA complexes increased intracellular levels of cyclic AMP. Taken together, these data indicate that stimulation of mononuclear phagocytes via the low-affinity receptor Fc epsilon RII or rising intracellular concentrations of cyclic AMP leads to an enhanced expression of iNOS. Evidence in favor of the involvement of cyclic AMP in the signaling pathway linked to Fc epsilon RII is provided by the effect of IgE/DNP-BSA complexes on intracellular cyclic AMP levels and by the additive effect produced by dibutyryl cyclic AMP on NO production elicited by IgE/DNP-BSA complexes.
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Alonso A, Carvalho J, Alonso-Torre SR, Núñez L, Boscá L, Sánchez Crespo M. Nitric oxide synthesis in rat peritoneal macrophages is induced by IgE/DNP complexes and cyclic AMP analogues. Evidence in favor of a common signaling mechanism. THE JOURNAL OF IMMUNOLOGY 1995. [DOI: 10.4049/jimmunol.154.12.6475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The production of nitric oxide was studied in rat adherent peritoneal cells stimulated with preformed IgE/DNP-BSA complexes made of IgE obtained from a secreting hybridoma. Stimulation with complexes at equivalence induced both the production of NO and an increased expression of the mRNA of the inducible isoform of NO synthase (iNOS). Production of NO was also elicited by a rabbit polyclonal F(ab')2 anti-CD23 cross-reacting with rat CD23. Because IgE/DNP-BSA complexes did not elicit Ca2+ mobilization and genistein did not influence the production of NO, cyclic AMP was considered as an alternative signaling molecule. Combination of a suboptimal concentration of dibutyryl cyclic AMP and IgE/DNP-BSA complexes showed an additive effect on NO production, whereas this was not observed when the agonists were used at supraoptimal doses. The inhibitor of cyclic AMP-specific phosphodiesterase IV, rolipram, which acts on the enzyme isoform predominantly expressed in inflammatory cells, also induced the production of NO. Furthermore, IgE/DNP-BSA complexes increased intracellular levels of cyclic AMP. Taken together, these data indicate that stimulation of mononuclear phagocytes via the low-affinity receptor Fc epsilon RII or rising intracellular concentrations of cyclic AMP leads to an enhanced expression of iNOS. Evidence in favor of the involvement of cyclic AMP in the signaling pathway linked to Fc epsilon RII is provided by the effect of IgE/DNP-BSA complexes on intracellular cyclic AMP levels and by the additive effect produced by dibutyryl cyclic AMP on NO production elicited by IgE/DNP-BSA complexes.
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Sánchez-Doblado F, Terrón J, Sánchez-Nieto B, Arráns R, Errazquin L, Biggs D, Lee C, Núñez L, Delgado A, Muñiz J. Verification of an on line in vivo semiconductor dosimetry system for TBI with two TLD procedures. Med Dosim 1995. [DOI: 10.1016/0958-3947(94)01490-f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Sánchez-Doblado F, Terrón JA, Sánchez-Nieto B, Arráns R, Errazquin L, Biggs D, Lee C, Núñez L, Delgado A, Muñiz JL. Verification of an on line in vivo semiconductor dosimetry system for TBI with two TLD procedures. Radiother Oncol 1995; 34:73-7. [PMID: 7792402 DOI: 10.1016/0167-8140(94)01490-t] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This work presents the verification of an on line in vivo dosimetry system based on semiconductors. Software and hardware has been designed to convert the diode signal into absorbed dose. Final verification was made in the form of an intercomparison with two independent thermoluminiscent (TLD) dosimetry systems, under TBI conditions.
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Puglielli L, Amigo L, Arrese M, Núñez L, Rigotti A, Garrido J, González S, Mingrone G, Greco AV, Accatino L. Protective role of biliary cholesterol and phospholipid lamellae against bile acid-induced cell damage. Gastroenterology 1994; 107:244-54. [PMID: 8020668 DOI: 10.1016/0016-5085(94)90083-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND/AIMS Bile salts (BS) are cytotoxic agents, but cell damage is not observed in the hepatobiliary system. We hypothesized that biliary lipid vesicles (unilamellae and multilamellae) could have a protective role against BS-induced cytotoxicity. METHODS Biliary lipid lamellar secretion was induced by feeding rats with 0.5% diosgenin. Cytoprotection was assessed in bile duct-obstructed rats and by incubating human erythrocytes with sodium taurocholate. RESULTS Biliary cholesterol concentration increased > 300% in diosgenin-fed rats; electron microscopic examination showed a great abundance of lipid lamellar vesicles in bile and within the canaliculi. After bile duct obstruction, serum hepatic enzyme activities were significantly lower in diosgenin-fed rats. Histologically severe and confluent hepatocellular necrosis was only observed in control rats. Biliary lamellar lipid material significantly reduced the BS-induced hemolytic effect in vitro in a concentration-dependent manner. This protective effect correlated to a progressive decrease in the intermicellar BS concentration. Phosphatidylcholine or cholesterol, alone or as lamellar structures, also showed cytoprotective effect in vitro but always less than native biliary lamellae. CONCLUSIONS These results support the concept that native biliary cholesterol phospholipid lamellae represent an important cytoprotective factor for hepatocytes and biliary epithelial cells against BS-induced damage.
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