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Andrade-Molina DA, Morey-León GA, Muñoz-Mawyin KE, Cruz-Fatuly FF, Fernández-Cadena JC, Cárdenas P. First sequenced cases of Omicron BA.2 sublineage in Ecuador. Virus Res 2023; 334:199169. [PMID: 37406934 PMCID: PMC10410591 DOI: 10.1016/j.virusres.2023.199169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 07/01/2023] [Accepted: 07/02/2023] [Indexed: 07/07/2023]
Abstract
The largest wave of infection with SARS-CoV-2 virus in Ecuador was observed in mid-December 2021 and early January 2022, driven by B.1.1.529/BA (Omicron) variant. During the second half of March, an increase in the number of daily cases was observed and coincided with the emergence of the BA.2 variant, which we describe in the present study. The first sequenced five cases of SARS-CoV-2 21L/BA.2 in Ecuador were identified using variant specific genotyping by qPCR and confirmed by whole genome sequencing (WGS). The first sequenced Ecuadorian BA.2 isolate was obtained from a person with international travel history who became symptomatic 3 days after travelling, whereas in the other cases no travel history was recorded.
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Affiliation(s)
- D A Andrade-Molina
- Omics Sciences Laboratory, Faculty of Health Sciences, Universidad Espíritu Santo, Samborondón, Ecuador.
| | - G A Morey-León
- Faculty of Health Sciences, Universidad de Guayaquil, Guayaquil, Ecuador
| | - K E Muñoz-Mawyin
- Omics Sciences Laboratory, Faculty of Health Sciences, Universidad Espíritu Santo, Samborondón, Ecuador
| | - F F Cruz-Fatuly
- Omics Sciences Laboratory, Faculty of Health Sciences, Universidad Espíritu Santo, Samborondón, Ecuador
| | | | - P Cárdenas
- Institute of Microbiology, Universidad San Francisco de Quito, Quito, Ecuador
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2
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Casado-Barragán F, Lazcano-Páez G, Larenas PE, Aguirre-Delgadillo M, Olivares-Aravena F, Witto-Oyarce D, Núñez-Allimant C, Silva K, Nguyen QM, Cárdenas P, Kassan M, Gonzalez AA. Increased Renal Medullary NOX-4 in Female but Not Male Mice during the Early Phase of Type 1 Diabetes: Potential Role of ROS in Upregulation of TGF-β1 and Fibronectin in Collecting Duct Cells. Antioxidants (Basel) 2023; 12:antiox12030729. [PMID: 36978977 PMCID: PMC10045926 DOI: 10.3390/antiox12030729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/08/2023] [Accepted: 03/11/2023] [Indexed: 03/18/2023] Open
Abstract
Chronic diabetes mellitus (DM) can lead to kidney damage associated with increased reactive oxygen species (ROS), proteinuria, and tubular damage. Altered protein expression levels of transforming growth factor-beta 1 (TGF-β1), fibronectin, and renal NADPH oxidase (NOX-4) are associated with the profibrotic phenotype in renal tubular cells. NOX-4 is one of the primary sources of ROS in the diabetic kidney and responsible for the induction of profibrotic factors in collecting duct (CD) cells. The renal medulla is predominantly composed of CDs; in DM, these CD cells are exposed to high glucose (HG) load. Currently there is no published literature describing the expression of these markers in the renal medulla in male and female mice during the early phase of DM, or the role of NOX-4-induced ROS. Our aim was to evaluate changes in transcripts and protein abundances of TGF-β1, fibronectin, and NOX-4 along with ROS levels in renal medullary tissues from male and female mice during a short period of streptozotocin (STZ)-induced type 1 DM and the effect of HG in cultured CD cells. CF-1 mice were injected with or without a single dose of STZ (200 mg/kg) and euthanized at day 6. STZ females showed higher expression of fibronectin and TGF-β1 when compared to control mice of either gender. Interestingly, STZ female mice showed a >30-fold increase on mRNA levels and a 3-fold increase in protein levels of kidney medullary NOX-4. Both male and female STZ mice showed increased intrarenal ROS. In primary cultures of inner medullary CD cells exposed to HG over 48 h, the expression of TGF-β1, fibronectin, and NOX-4 were augmented. M-1 CD cells exposed to HG showed increased ROS, fibronectin, and TGF-β1; this effect was prevented by NOX-4 inhibition. Our data suggest that at as early as 6 days of STZ-induced DM, the expression of profibrotic markers TGF-β1 and fibronectin increases in renal medullary CD cells. Antioxidants mechanisms in male and female in renal medullary tissues seems to be differentially regulated by the actions of NOX-4.
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Affiliation(s)
- Felipe Casado-Barragán
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Geraldine Lazcano-Páez
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Paulina E. Larenas
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | | | | | - Daniela Witto-Oyarce
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Camila Núñez-Allimant
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Katherin Silva
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Quynh My Nguyen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Pilar Cárdenas
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
| | - Modar Kassan
- College of Dental Medicine, Lincoln Memorial University, Knoxville, TN 37917, USA
| | - Alexis A. Gonzalez
- Institute of Chemisry, Pontificia Universidad Católica de Valparaíso, Valparaíso 2950, Chile
- Correspondence:
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3
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Ortiz A, Cárdenas P, Peralta M, Rodríguez H, Ortiz J, Vazquez E. Central retinal artery occlusion as an ophthalmic complication after snakebite. Arch Soc Esp Oftalmol (Engl Ed) 2022; 97:587-592. [PMID: 36088246 DOI: 10.1016/j.oftale.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Snakebite causes 421.000-1.200.000 poisonings per year due to and hematotoxicity, neurotoxicity y vasculotoxicity. Ophthalmological manifestations secondary to snake bites are rare. If the snake belongs to the Viperidae family, the most frequent ophthalmologic manifestations are macular infarction, chronic open-angle glaucoma, and retinal or vitreous hemorrhage. Central retinal artery occlusion is an extremely rare ocular complication. We report the case of a 30-year-old patient, who consulted due to poor vision in her left eye weeks after suffering a snake bite (Bothrops atrox) in her left lower limb. The diagnosis was a central retinal artery occlusion in the left eye with abnormal findings in the ophthalmological physical examination and in complementary retinal and neuro-ophthalmological tests.
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Affiliation(s)
- A Ortiz
- Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia; Clínica Oftalmológica Aljaorza, Machala, Ecuador.
| | - P Cárdenas
- Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia
| | - M Peralta
- Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia; Clínica Oftalmológica Aljaorza, Machala, Ecuador
| | - H Rodríguez
- Fundación Oftalmológica de Santander (FOSCAL), Floridablanca, Colombia
| | - J Ortiz
- Clínica Oftalmológica Aljaorza, Machala, Ecuador
| | - E Vazquez
- Clínica Oftalmológica Aljaorza, Machala, Ecuador
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4
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Fernandez-Cadena JC, Carvajal M, Muñoz E, Prado-Vivar B, Marquez S, Proaño S, Bayas R, Guadalupe JJ, Becerra-Wong M, Gutierrez B, Morey-Leon G, Trueba G, Grunauer M, Barragán V, Rojas-Silva P, Andrade-Molina D, Cárdenas P. First case of within-host co-infection of different SARS-CoV-2 variants in Ecuador. New Microbes New Infect 2022; 48:101001. [PMID: 35818397 PMCID: PMC9259011 DOI: 10.1016/j.nmni.2022.101001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 06/24/2022] [Indexed: 11/28/2022] Open
Abstract
Background COVID-19 infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause mild symptoms to severe illness and death. Co-infections of SARS-CoV-2 with other respiratory viruses have been described. However, two SARS-CoV-2 lineage co-infection have been rarely reported. Methodology A genotyping analysis and two different types of whole genome sequencing were performed (Illumina MiniSeq and ONT MinION). When examining the phylogenetic analysis in NextClade and Pangolin webservers, and considering the genotyping findings, conflicting results were obtained. Results The raw data of the sequencing was analyzed, and nucleotide variants were identified between different reads of the virus genome. B.1 and P.1 lineages were identified within the same sample. Conclusions We concluded that this is a co-infection case with two SARS-CoV-2 lineages, the first one reported in Ecuador.
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Affiliation(s)
| | - M Carvajal
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - E Muñoz
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - B Prado-Vivar
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - S Marquez
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - S Proaño
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - R Bayas
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - J J Guadalupe
- Universidad San Francisco de Quito, COCIBA, Laboratorio de Biotecnología Vegetal, Ecuador
| | - M Becerra-Wong
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - B Gutierrez
- Universidad San Francisco de Quito, COCIBA, Laboratorio de Biotecnología Vegetal, Ecuador.,Departament of Zoology, University of Oxford, UK
| | | | - G Trueba
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - M Grunauer
- Universidad San Francisco de Quito, COCSA, Escuela de Medicina, Ecuador.,Unidad de Cuidados Intensivos, Hospital de los Valles, Quito, Ecuador
| | - V Barragán
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | - P Rojas-Silva
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
| | | | - P Cárdenas
- Universidad San Francisco de Quito, COCIBA, Instituto de Microbiología, Ecuador
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5
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Guerrero A, Visniauskas B, Cárdenas P, Figueroa SM, Vivanco J, Salinas-Parra N, Araos P, Nguyen QM, Kassan M, Amador CA, Prieto MC, Gonzalez AA. α-Ketoglutarate Upregulates Collecting Duct (Pro)renin Receptor Expression, Tubular Angiotensin II Formation, and Na + Reabsorption During High Glucose Conditions. Front Cardiovasc Med 2021; 8:644797. [PMID: 34179130 PMCID: PMC8220822 DOI: 10.3389/fcvm.2021.644797] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/13/2021] [Indexed: 11/22/2022] Open
Abstract
Diabetes mellitus (DM) causes high glucose (HG) levels in the plasma and urine. The (pro)renin receptor (PRR) is a key regulator of renal Na+ handling. PRR is expressed in intercalated (IC) cells of the collecting duct (CD) and binds renin to promote angiotensin (Ang) II formation, thereby contributing to Na+ reabsorption. In DM, the Kreb's cycle is in a state of suppression in most tissues. However, in the CD, expression of glucose transporters is augmented, boosting the Kreb's cycle and consequently causing α-ketoglutarate (αKG) accumulation. The αKG receptor 1 (OXGR1) is a Gq-coupled receptor expressed on the apical membrane of IC cells of the CD. We hypothesize that HG causes αKG secretion and activation of OXGR1, which increases PRR expression in CD cells. This effect then promotes intratubular AngII formation and Na+ reabsorption. To test this hypothesis, streptozotocin (STZ)-induced diabetic mice were treated with or without montelukast (ML), an OXGR1 antagonist, for 6 days. STZ mice had higher urinary αKG and PRR expression along with augmented urinary AngII levels and Na+ retention. Treatment with ML prevented all these effects. Similarly, primary cultured inner medullary CD cells treated with HG showed increased PRR expression, while OXGR1 antagonist prevented this effect. αKG increases PRR expression, while treatments with ML, PKC inhibition, or intracellular Ca2+ depletion impair this effect. In silico analysis suggested that αKG binds to mouse OXGR1. These results indicate that HG conditions promote increased levels of intratubular αKG and OXGR1-dependent PRR upregulation, which impact AngII formation and Na+ reabsorption.
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Affiliation(s)
- Aarón Guerrero
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Bruna Visniauskas
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States
| | - Pilar Cárdenas
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Stefanny M. Figueroa
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Jorge Vivanco
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Nicolas Salinas-Parra
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Patricio Araos
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Quynh My Nguyen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA, United States
| | - Modar Kassan
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Cristián A. Amador
- Laboratory of Renal Physiopathology, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Minolfa C. Prieto
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, United States
| | - Alexis A. Gonzalez
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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6
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Pinto C, Cárdenas P, Osses N, Henríquez JP. Characterization of Wnt/β-catenin and BMP/Smad signaling pathways in an in vitro model of amyotrophic lateral sclerosis. Front Cell Neurosci 2013; 7:239. [PMID: 24348333 PMCID: PMC3847560 DOI: 10.3389/fncel.2013.00239] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/13/2013] [Indexed: 12/11/2022] Open
Abstract
Different pathways activated by morphogens of the early embryonic development, such as the Wnt and the Bone Morphogenetic Protein (BMP) ligands, are involved in diverse physiological and pathological conditions of the nervous system, including neurodegeneration. In this work, we have analyzed the endogenous activity of the canonical Wnt/β-catenin and BMP/Smad-dependent pathways in an in vitro model of amyotrophic lateral sclerosis (ALS), given by motor neuron-like NSC34 cells stably expressing wild-type or G93A mutated forms of human Cu/Zn superoxide dismutase-1 (SOD1). As ALS-derived motor neurons, NSC34 cells expressing mutated hSOD1 show a decreased proliferation rate, are more susceptible to oxidation-induced cell death and display Golgi fragmentation. In addition, they display an impaired ability to induce the expression of the motor neuronal marker Hb9 and, consistently, to morphologically differentiate into a motor neuronal phenotype. Regarding signaling, our data show that the transcriptional activity associated to the Wnt/β-catenin pathway is decreased, a finding possibly associated to the cytosolic aggregation of β-catenin. In turn, the BMP-dependent phosphorylation of Smad1 and the transcriptional activation of the BMP/Smad pathway is increased in the pathologic model. Together, these findings suggest that Wnt/β-catenin and the BMP-dependent pathways could play relevant roles in the neurodegeneration of motor neurons in the context of ALS.
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Affiliation(s)
- Cristina Pinto
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
| | - Pilar Cárdenas
- Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de Valparaíso Valparaiso, Chile
| | - Nelson Osses
- Institute of Chemistry, Faculty of Sciences, Pontificia Universidad Católica de Valparaíso Valparaiso, Chile
| | - Juan P Henríquez
- Laboratory of Developmental Neurobiology, Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy, Universidad de Concepción Concepción, Chile
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7
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Abstract
Systematics is nowadays facing new challenges with the introduction of new concepts and new techniques. Compared to most other phyla, phylogenetic relationships among sponges are still largely unresolved. In the past 10 years, the classical taxonomy has been completely overturned and a review of the state of the art appears necessary. The field of taxonomy remains a prominent discipline of sponge research and studies related to sponge systematics were in greater number in the Eighth World Sponge Conference (Girona, Spain, September 2010) than in any previous world sponge conferences. To understand the state of this rapidly growing field, this chapter proposes to review studies, mainly from the past decade, in sponge taxonomy, nomenclature and phylogeny. In a first part, we analyse the reasons of the current success of this field. In a second part, we establish the current sponge systematics theoretical framework, with the use of (1) cladistics, (2) different codes of nomenclature (PhyloCode vs. Linnaean system) and (3) integrative taxonomy. Sponges are infamous for their lack of characters. However, by listing and discussing in a third part all characters available to taxonomists, we show how diverse characters are and that new ones are being used and tested, while old ones should be revisited. We then review the systematics of the four main classes of sponges (Hexactinellida, Calcispongiae, Homoscleromorpha and Demospongiae), each time focusing on current issues and case studies. We present a review of the taxonomic changes since the publication of the Systema Porifera (2002), and point to problems a sponge taxonomist is still faced with nowadays. To conclude, we make a series of proposals for the future of sponge systematics. In the light of recent studies, we establish a series of taxonomic changes that the sponge community may be ready to accept. We also propose a series of sponge new names and definitions following the PhyloCode. The issue of phantom species (potential new species revealed by molecular studies) is raised, and we show how they could be dealt with. Finally, we present a general strategy to help us succeed in building a Porifera tree along with the corresponding revised Porifera classification.
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Affiliation(s)
- P Cárdenas
- Département Milieux et Peuplements Aquatiques, Muséum National d'Histoire Naturelle, UMR 7208 "BOrEA", Paris, France
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8
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Bustamante M, Carvajal C, Gottlieb B, Contreras JE, Uribe M, Melkonian E, Cárdenas P, Amadori A, Parra JA. [A new instrument for the evaluation of the medical profession. Use of the OSCE method]. Rev Med Chil 2000; 128:1039-44. [PMID: 11349493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND Objective structured clinical examination has advantages over traditional oral examination of medical student. However, it is not routinely used in Chile. AIM To describe the objective structured clinical examination system and report the results of its first use with Chilean medical students. MATERIAL AND METHODS Thirteen interns ware evaluated at the end of their surgical rotation, using the objective structured clinical examination. Thirteen stations were structured for this examination: one for history taking, two for physical examination, four for problem solving and knowledge, one for radiological interpretation, one for instrumental recognition, one for skills and one for text comprehension. There were a total of 88 questions. RESULTS All students exceeded 60% of requirements. Mean approval score was 73%. The higher score was 80% and the lower 61%. Ten students had a score over 70%. The method was well accepted by teachers and students. CONCLUSIONS This first local experience with the objective structured clinical examination was successful.
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Affiliation(s)
- M Bustamante
- Departamento de Cirugía, Campus Oriente, Facultad de Medicina, Universidad de Chile
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9
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Chacín J, Cárdenas P, Lobo P, Hernández I. Secretory and metabolic effects of ethanol in the isolated amphibian gastric mucosa. Gastroenterology 1991; 100:1288-95. [PMID: 1901555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The effects of pure ethanol and some alcoholic beverages on acid secretion and metabolism were examined in the isolated toad gastric mucosa. Pure ethanol applied to the luminal side or to the submucosal side at low concentrations (2%-10%) was a potent stimulant of acid secretion, whereas high concentrations (greater than or equal to 20%) were inhibitory. Cimetidine and calcium-free solutions did not abolish the secretory effect of ethanol. Beer and wine, but not rum and whisky, caused a significant stimulation of acid secretion. Respiration was progressively increased by ethanol at concentrations between 2% and 20%. This effect was not affected by cimetidine or by SCH 28080, an inhibitor of the gastric hydrogen-potassium-stimulated adenosine triphosphatase. Ethanol (10%) significantly increased by 46% the tissue lactate-pyruvate ratio. The oxidations of glucose, butyrate, and acetate were progressively reduced by low concentrations of ethanol (5% and 10%). The results indicate that (a) low concentrations of ethanol and alcoholic beverages with low ethanol content are direct stimulants of acid secretion and (b) the secretory and metabolic effects of low concentrations of ethanol seem to be mediated via its oxidation.
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Affiliation(s)
- J Chacín
- Laboratorio de Investigaciones Gastrointestinales, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela
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10
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Cárdenas P, Riveros B, Martínez V. [Chronic active hepatitis induced by nitrofurantoin]. Rev Med Chil 1988; 116:1172-6. [PMID: 3267901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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11
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Chacín J, Cárdenas P, Lobo P, Subero O. Role of calcium in secretory and metabolic effects of substrates in the gastric mucosa. Am J Physiol 1986; 251:G161-8. [PMID: 3090895 DOI: 10.1152/ajpgi.1986.251.2.g161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The role of extracellular Ca2+ in the effects and oxidation of metabolic substrates was investigated in the isolated toad gastric mucosa. In the presence of lipoate, the stimulating effect of 10 mM glucose on spontaneous acid secretion was significantly reduced by 76% in Ca2+-free solutions. The inhibition was overcome by addition of 5 mM Ca2+. The increment in respiration induced by glucose was also blocked in the absence of external Ca2+. The effect of 10 mM pyruvate on acid secretion was inhibited by 37% in Ca2+-free solutions. The secretory responses induced by 10 mM butyrate and 10 mM octanoate were not significantly affected by Ca2+-free solutions. The rates of oxidation of [14C]-glucose and [14C]pyruvate were significantly reduced by incubating in Ca2+-free solutions containing 0.1 mM of EGTA. When O2 uptake and glucose oxidation were measured simultaneously in the same preparation, the increment in the rate of glucose oxidation accounted for by 43% of the total increase of respiration observed in the presence of Ca2+. The rates of oxidation of [14C]butyrate and [14C]acetate were not significantly affected by Ca2+-free solutions. The rate of oxidation of [14C]glucose exhibited saturation kinetics versus concentration and was lower in the absence of external Ca2+ under a range of glucose concentrations. Similar results were observed when the experiments were performed in the absence of external potassium to block the acid secretory process. Ca2+ stimulated the rate of glucose oxidation in a dose-dependent manner. The kinetics of 45Ca2+ efflux and 45Ca2+ uptake were not significantly affected by glucose and butyrate.(ABSTRACT TRUNCATED AT 250 WORDS)
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12
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Abstract
The substrate-level energy dependence of acid secretion was investigated in the human gastric mucosa in vitro using biopsy specimens obtained during fiberoptic gastroscopy in symptomatic patients. The oxygen consumption and the accumulation of aminopyrine were used as indexes of secretory activity. Basal and histamine-stimulated oxygen uptake by fundic biopsy specimens were not affected by medications (pethidine and diazepam) administered during gastroscopy. Under substrate-depleted conditions, the oxygen consumption and the aminopyrine accumulation of fundic mucosa were not significantly increased by histamine. Stimulation of functional activities by gastric secretagogues was observed only in the presence of exogenous substrates. The ability of various substrates to support acid formation in the presence of gastric secretagogues was evaluated. Carbohydrates were found to be effective substrates in supporting the functional responses of the tissue, with glucose being the most effective. Propionate, butyrate, beta-hydroxybutyrate, and octanoate were ineffective as substrates. Glucose by itself, but not butyrate, significantly increased oxygen uptake and aminopyrine accumulation. The results suggest that the human gastric mucosa, in vitro, has an absolute requirement for metabolic substrates to support secretory responses and that carbohydrates seem to be the preferential substrates.
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13
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Chacín J, Cárdenas P. Inhibition by cimetidine of the secretory and respiratory responses induced by theophylline and cyclic AMP in the amphibian gastric mucosa. Comp Biochem Physiol C Comp Pharmacol Toxicol 1983; 74:195-9. [PMID: 6132765 DOI: 10.1016/0742-8413(83)90174-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. The effects of cimetidine, a histamine H2-receptor antagonist, on acid secretory and respiratory responses induced by histamine, theophylline and dibutyryl cyclic AMP were investigated in the in vitro toad gastric mucosa. 2. Histamine- and theophylline-stimulated acid secretion was competitively inhibited by cimetidine. A significant but lesser degree of inhibition was observed on oxygen uptake. 3. Cimetidine significantly inhibited acid secretion and oxygen uptake stimulated by dibutyryl cyclic AMP. 4. The results may suggest that cimetidine may have an additional action beyond the point of cyclic AMP in the oxyntic cells.
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