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Menéndez CA, Verde AR, Alarcón LM, Accordino SR, Appignanesi GA. Influence of docosahexaenoic acid on the interfacial behavior of cholesterol-containing lipid membranes: Interactions with small amphiphiles and hydration properties. Biophys Chem 2023; 301:107081. [PMID: 37542837 DOI: 10.1016/j.bpc.2023.107081] [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: 05/30/2023] [Revised: 07/11/2023] [Accepted: 07/30/2023] [Indexed: 08/07/2023]
Abstract
Cholesterol is known to significantly modify both the structural and the dynamical properties of lipid membranes. On one side, the presence of free cholesterol molecules has been determined to stiffen the membrane bilayer by stretching the hydrophobic tails. Additionally, recent experimental and computational findings have made evident the fact that cholesterol also alters the dynamics and the hydration properties of the polar head groups of DPPC model lipid membranes. In turn, we have recently shown that the Omega-3 fatty acid docosahexaenoic acid, DHA, counteracts the effect of cholesterol on DPPC membrane's mechanical properties by fluidizing the bilayer. However, such behavior represents in fact a global outcome dominated by the larger lipid hydrophobic tails that neither discriminates between the different parts of the membrane nor elucidates the effect on membrane hydration and binding properties. Thus, we now perform molecular dynamics simulations to scrutinize the influence of DHA on the interfacial behavior of cholesterol-containing lipid membranes by characterizing their hydration properties and their binding to amphiphiles. We find that while cholesterol destabilizes interactions with amphiphiles and slightly weakens the lipid's hydration layer, the incorporation of DHA practically restores the interfacial behavior of pure DPPC.
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Affiliation(s)
- C A Menéndez
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina.
| | - A R Verde
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - L M Alarcón
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - S R Accordino
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - G A Appignanesi
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
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Pedroni VI, Sierra MB, Alarcón LM, Verde AR, Appignanesi GA, Morini MA. A certain proportion of docosahexaenoic acid tends to revert structural and dynamical effects of cholesterol on lipid membranes. Biochim Biophys Acta Biomembr 2021; 1863:183584. [PMID: 33571481 DOI: 10.1016/j.bbamem.2021.183584] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/29/2021] [Accepted: 02/05/2021] [Indexed: 12/19/2022]
Abstract
This work investigates how docosahexaenoic acid (DHA) modifies the effect of Cholesterol (Chol) on the structural and dynamical properties of dipalmitoylphosphatidylcholine (DPPC) membrane. We employ low-cost and non-invasive methods: zeta potential (ZP), conductivity, density, and ultrasound velocity, complemented by molecular dynamics simulations. Our studies reveal that 30% of DHA added to the DPPC-Chol system tends to revert Chol action on a model lipid bilayer. Results obtained in this work shed light on the effect of polyunsaturated fatty acids - particularly DHA - on lipid membranes, with potential preventive applications in many diseases, e.g. neuronal as, Alzheimer's disease, and viral, as Covid-19.
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Affiliation(s)
- V I Pedroni
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - M B Sierra
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - L M Alarcón
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - A R Verde
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - G A Appignanesi
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina
| | - M A Morini
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Buenos Aires, Argentina.
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Pérez HA, Alarcón LM, Verde AR, Appignanesi GA, Giménez RE, Disalvo EA, Frías MA. Effect of cholesterol on the hydration properties of ester and ether lipid membrane interphases. Biochim Biophys Acta Biomembr 2020; 1863:183489. [PMID: 33075308 DOI: 10.1016/j.bbamem.2020.183489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 01/07/2023]
Abstract
Fluorescence spectroscopy and Molecular Dynamics results show that cholesterol reduces water along the chains in ether lipids by changing the water distribution pattern between tightly and loosely bound water molecules. Water distribution was followed by emission spectra and generalized polarization of 6-dodecanoyl-2-dimethyl aminonaphthalene (Laurdan) inserted in 1,2-dimiristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (14: 0 Diether PC) membranes. Molecular Dynamics simulations indicate that the action of cholesterol could be different in ether PC in comparison to ester PC. In addition, Cholesterol seems to act "per se" as an additional hydration center in ether lipids. Regardless of the phase state, cholesterol both in DMPC and 14:0 Diether PC vesicles, changed the distribution of water molecules decreasing the dipole relaxation of the lipid interphase generating an increase in the non-relaxable population. Above 10% Cholesterol/14:0 Diether PC ratio vesicles' interphase present an environment around Laurdan molecules similar to that corresponding to ester PC.
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Affiliation(s)
- H A Pérez
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), RN 9 - Km 1125, 4206 Santiago del Estero, Argentina
| | - L M Alarcón
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - A R Verde
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - G A Appignanesi
- Laboratorio de Fisicoquímica, INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - R E Giménez
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), RN 9 - Km 1125, 4206 Santiago del Estero, Argentina
| | - E A Disalvo
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), RN 9 - Km 1125, 4206 Santiago del Estero, Argentina
| | - M A Frías
- Applied Biophysics and Food Research Center (Centro de Investigaciones en Biofisica Aplicada y Alimentos, CIBAAL, National University of Santiago del Estero and CONICET), RN 9 - Km 1125, 4206 Santiago del Estero, Argentina.
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Ríos A, López-Navas A, Gutiérrez PR, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Fernández A, De Jesús MT, Lana A, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Carrillo J, Sánchez Á, Alarcón LM, Parrilla P, Ramírez P. What Reasons Lead Spanish Medical Students Not to Be in Favor of Organ Donation? Transplant Proc 2020; 52:443-445. [PMID: 32057503 DOI: 10.1016/j.transproceed.2019.11.040] [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: 08/29/2019] [Accepted: 11/06/2019] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Despite sensitization of medical students toward the donation of organs, a non-negligible percentage of students are not in favor of donation. OBJECTIVE To analyze the reasons of Spanish medical students who do not have a favorable attitude toward the donation of their own organs after death. METHOD The population under study is medical students in Spanish universities, using the database of the International Donor Collaborative Project, stratified by geographic area and academic year. The questionnaire completion was anonymous and self-administered. The study group is medical students with an unfavorable attitude toward organ donation. The assessment instrument used is a validated questionnaire of attitude toward the donation of organs for transplant, "PCID-DTO-Ríos." The reasons against the donation are valued in the questionnaire through a question. RESULTS Of the participants included in the PCID, students who are not in favor of organ donation were selected (n = 1899). Of them, 8.1% (n = 154) are against and 91.1% (n = 1745) are doubtful. The main reasons indicated are the fear of apparent death in 11.4% of respondents, fear of possible mutilation after donation in 11.1%, and religious reasons in 2.6%. Of those, 6.9% indicate other reasons but do not clearly specify the reasons, using words such as "fear" (2.5%) or "doubts about the process" (4.1%); 66.2% (n = 1257) indicated an "assertive refusal" ("I don't want to express my reasons"). CONCLUSION Twenty percent of Spanish medical students are not in favor of donating their organs and are not in favor of showing their reasons.
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Affiliation(s)
- A Ríos
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain.
| | - A López-Navas
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Psychology, Catholic University of Murcia (UCAM), Murcia, Spain
| | - P R Gutiérrez
- Urology Service (University Hospital Complex of the Canary Islands, CHUC) and Department of Surgery (University of La Laguna, ULL) San Cristóbal de La Laguna, Tenerife, Spain
| | - F J Gómez
- University of Granada, Granada, Spain
| | - J Iriarte
- University of Navarra, Navarra, Spain
| | - R Herruzo
- Autonomous University of Madrid, Madrid, Spain
| | - G Blanco
- BPH Surgery and Liver Transplant Service, Badajoz University Hospital Complex, Infanta Cristina Hospital, Badajoz, Spain
| | - F J Llorca
- University of Cantabria, Santander, Spain
| | - A Asunsolo
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, Universidad de Alcalá Scientific-Technological Campus, Alcalá de Henares, Madrid, Spain
| | - P Sánchez
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - A Fernández
- Department of Basic Biomedical Sciences, Faculty of Biomedical Sciences, Universidad Europea de Madrid, Madrid, Spain
| | | | - A Lana
- Faculty of Medicine and Health Sciences, Area of Preventive Medicine and Public Health, University of Oviedo, Oviedo, Spain
| | - L Fuentes
- Department of Pharmacology and Physiology School of Health and Sports Sciences, University of Zaragoza, Huesca, Spain
| | - J R Hernández
- University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - J Virseda
- University of Castilla La Mancha, Albacete, Spain
| | - J Yelamos
- Endocrinology and Nutrition Service, Virgen de la Arrixaca University Clinical Hospital, El Palmar, Murcia Health Service, Murcia, Spain
| | - J A Bondía
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - J Carrillo
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain
| | - Á Sánchez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain
| | - L Martínez Alarcón
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Parrilla
- Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Ramírez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain
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Ríos A, López-Navas A, Gutiérrez PR, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Fernández A, De Jesús MT, Lana A, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Carrillo J, Sánchez Á, Alarcón LM, Parrilla P, Ramírez P. Are Medical Students of Non-Spanish Nationality Studying in Spain as Sensitized to Transplantation as Those of Spanish Nationality? Transplant Proc 2020; 52:435-438. [PMID: 32057498 DOI: 10.1016/j.transproceed.2019.11.039] [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: 08/29/2019] [Accepted: 11/06/2019] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Awareness of organ donation among Spanish doctors and medical students is very positive. However, the emerging group of professionals of non-Spanish nationality studying in Spain has not been analyzed. OBJECTIVE To analyze the differences in the attitudes toward the different types of donation among medical students, according to their nationality. METHODS The population under study is medical students in Spanish universities using the database of the International Collaborative Donor Project, stratified by geographic area and academic year. Groups under study include students of non-Spanish nationality as group 1 (n = 1570) and students of Spanish nationality as Group 2 (n = 7705). Instruments are validated questionnaires of attitude toward donation "PCID-DTO-Ríos," "PCID-DVR-Ríos," "PCID-DVH-Ríos," and "PCID-XenoTx-Ríos." RESULTS The attitude toward the donation of own organs after death is similar in both groups (P = .703). Non-Spaniards are 79.2% in favor compared to 79.6% of Spaniards. Living kidney donation, both unrelated (33.3% vs 29.3% in favor; P = .001) and related (91.2% vs 89, 6% in favor; P = .047), is more favorable among non-Spanish students. There are no differences regarding non-related living liver donation (29.7% vs 29.3% in favor; P = .063), but there are differences in the results for related living liver donation (94.1% vs 88%; P < .001). The attitude toward xenotransplantation of organs is similar (80.8% vs 80.8%; P = .999). CONCLUSIONS Awareness of the donation of organs among Spanish medical students is similar to non-Spanish students studying in Spain, except the attitude toward living donation.
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Affiliation(s)
- A Ríos
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain.
| | - A López-Navas
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Psychology, Catholic University of Murcia (UCAM), Murcia, Spain
| | - P R Gutiérrez
- Urology Service (University Hospital Complex of the Canary Islands, CHUC) and Department of Surgery (University of La Laguna, ULL) San Cristóbal de La Laguna, Tenerife, Spain
| | - F J Gómez
- University of Granada, Granada, Spain
| | - J Iriarte
- University of Navarra, Navarra, Spain
| | - R Herruzo
- Autonomous University of Madrid, Madrid, Spain
| | - G Blanco
- BPH Surgery and Liver Transplant Service. Badajoz University Hospital Complex, Infanta Cristina Hospital, Badajoz, Spain
| | - F J Llorca
- University of Cantabria, Santander, Spain
| | - A Asunsolo
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, Universidad de Alcalá Scientific-Technological Campus, Alcalá de Henares, Madrid, Spain
| | - P Sánchez
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - A Fernández
- Department of Basic Biomedical Sciences, Faculty of Biomedical Sciences, Universidad Europea de Madrid, Madrid, Spain
| | | | - A Lana
- Faculty of Medicine and Health Sciences, Area of Preventive Medicine and Public Health, University of Oviedo, Oviedo, Spain
| | - L Fuentes
- Department of Pharmacology and Physiology School of Health and Sports Sciences, University of Zaragoza, Huesca, Spain
| | - J R Hernández
- University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - J Virseda
- University of Castilla La Mancha, Albacete, Spain
| | - J Yelamos
- Endocrinology and Nutrition Service. Virgen de la Arrixaca University Clinical Hospital, El Palmar, Murcia Health Service, Murcia, Spain
| | - J A Bondía
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - J Carrillo
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain
| | - Á Sánchez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain
| | - L Martínez Alarcón
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Parrilla
- Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Ramírez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain
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Ríos A, López-Navas A, Gutiérrez PR, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Fernández A, De Jesús MT, Lana A, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Carrillo J, Sánchez Á, Alarcón LM, Parrilla P, Ramírez P. Information About Donation and Organ Transplantation Among Spanish Medical Students. Transplant Proc 2020; 52:446-448. [PMID: 32057497 DOI: 10.1016/j.transproceed.2019.11.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/06/2019] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Health professionals are asked to promote health, especially organ transplantation; however, they do not always have specific training. OBJECTIVE To analyze information about donation and organ transplantation among Spanish medical students. METHOD The population under study is medical students in Spanish universities using the database of the International Donor Collaborative Project, stratified by geographic area and academic year (n = 9275). The instrument used is the attitude questionnaire for organ donation for "PCID-DTO-Ríos" transplantation, validated with an explained variance of 63.203% and α = 0.834. The Student t test was applied together with the χ2 test, complemented by an analysis of the remainders, and Fisher's exact test was applied. RESULTS Of the students, 74% indicate that they have received information from university professors about organ transplant. Concerning specific issues with the donation, it is notable that only 66.7% (n = 6190) know and accept the concept of brain death as the death of a person. However, only 22% consider themselves as having good information, and 35.3% indicate that their information is scarce or void. Students indicate having received information about transplant from other extra-university sources, such as television and Internet (80.9%), books and magazines (73.2%), and the press (66.9%). From the information obtained in the sociofamilial field, 60.7% have obtained information from the family and 58.1% from friends. Of this information, 9% has been negative from friends, 7.5% from family, 6% from the Internet and television, and 4% from university professors. CONCLUSION Spanish medical students believe they have little information about organ transplantation and have received negative information.
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Affiliation(s)
- A Ríos
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain.
| | - A López-Navas
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Psychology, Catholic University of Murcia (UCAM), Murcia, Spain
| | - P R Gutiérrez
- Urology Service (University Hospital Complex of the Canary Islands, CHUC) and Department of Surgery (University of La Laguna, ULL) San Cristóbal de La Laguna, Tenerife, Spain
| | - F J Gómez
- University of Granada, Granada, Spain
| | - J Iriarte
- University of Navarra, Navarra, Spain
| | - R Herruzo
- Autonomous University of Madrid, Madrid, Spain
| | - G Blanco
- BPH Surgery and Liver Transplant Service, Badajoz University Hospital Complex, Infanta Cristina Hospital, Badajoz, Spain
| | - F J Llorca
- University of Cantabria, Santander, Spain
| | - A Asunsolo
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, Universidad de Alcala Scientific-Technological Campus, Alcala de Henares, Madrid, Spain
| | - P Sánchez
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - A Fernández
- Department of Basic Biomedical Sciences, Faculty of Biomedical Sciences, Universidad Europea de Madrid, Madrid, Spain
| | | | - A Lana
- Faculty of Medicine and Health Sciences, Area of Preventive Medicine and Public Health, University of Oviedo, Oviedo, Spain
| | - L Fuentes
- Department of Pharmacology and Physiology School of Health and Sports Sciences, University of Zaragoza, Huesca, Spain
| | - J R Hernández
- University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - J Virseda
- University of Castilla La Mancha, Albacete, Spain
| | - J Yelamos
- Endocrinology and Nutrition Service. Virgen de la Arrixaca University Clinical Hospital, El Palmar, Murcia Health Service, Murcia, Spain
| | - J A Bondía
- Faculty of Medicine, University of Málaga, Málaga, Spain
| | - J Carrillo
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, University of Murcia, Murcia, Spain
| | - Á Sánchez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain
| | - L Martínez Alarcón
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Parrilla
- Department of Surgery, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain
| | - P Ramírez
- International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante"), Murcia, Spain; Department of Surgery, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB - Virgen de la Arrixaca University Clinical Hospital, Murcia, Spain; Regional Transplant Center, Ministry of Health and Consumer Affairs of the Region of Murcia, Murcia, Spain
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7
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Ríos A, López-Navas A, López-López A, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Gutiérrez PR, Fernández A, de Jesús MT, Martínez Alarcón L, Lana A, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Hernández AM, Ayala MA, Ramírez P, Parrilla P. A Multicentre and stratified study of the attitude of medical students towards organ donation in Spain. Ethn Health 2019; 24:443-461. [PMID: 28665141 DOI: 10.1080/13557858.2017.1346183] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [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: 09/04/2016] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Medical students represent a new generation of medical thought, and if they have a favourable attitude towards organ donation this will greatly encourage its promotion. OBJECTIVE To analyse the attitude of medical students in Spanish universities towards the donation of their own organs and to determine the factors affecting this attitude. MATERIAL AND METHODS Type of study: A sociological, interdisciplinary, multicentre, and observational study in Spain. STUDY POPULATION Students studying a degree in medicine enrolled in Spain (n = 34,000). SAMPLE SIZE A sample of 9598 students (confidence of 99% and precision of ±1%), stratified by geographical area and academic year. Instrument of measurement: A validated questionnaire of attitude towards organ donation and transplantation (PCID-DTO RIOS) was self-administered and completed anonymously. RESULTS The questionnaire completion rate was 95.7% (n = 9.275). 80% were in favour of donation, 2% against and 18% were undecided. The following main variables were related to a favourable attitude: being of the female sex (Odds Ratio = 1.739); being in the sixth year of the degree (OR = 2.506); knowing a donor (OR = 1.346); having spoken about the subject with one's family (OR = 2.132) and friends (OR = 1.333); having a family circle that is in favour, more specifically, having a father (OR = 1.841), mother (OR = 2.538) or partner in favour (OR = 2.192); being a blood donor (OR = 2.824); acceptance of the mutilation of the body if it were necessary (OR = 2.958); and being an atheist or an agnostic (OR = 1.766). CONCLUSIONS Spanish medical students generally have a favourable attitude towards organ donation, although 20% are not in favour.
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Affiliation(s)
- A Ríos
- a International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante") , Murcia , Spain
- b Department of Surgery, Paediatrics, Obstetrics and Gynaecology , University of Murcia , Murcia , Spain
- c Transplant Unit, Surgery Service , IMIB - Virgen de la Arrixaca University Hospital , Murcia , Spain
- d Regional Transplant Centre , Consejería de Sanidad y Consumo de la Región de Murcia , Murcia , Spain
| | - A López-Navas
- a International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante") , Murcia , Spain
- e Department of Psychology , Universidad Católica San Antonio (UCAM) , Murcia , Spain
| | - A López-López
- f Department of Urology , San Juan University Hospital of Alicante , Alicante , Spain
| | - F J Gómez
- g Facultad de Medicina, Universidad de Granada , Granada , Spain
| | - J Iriarte
- h Facultad de Medicina, Universidad de Navarra , Navarra , Spain
| | - R Herruzo
- i Facultad de Medicina, Universidad Autónoma de Madrid , Madrid , Spain
| | - G Blanco
- j Servicio de Cirugía HBP y Trasplante Hepático , Complejo Hospitalario Universitario de Badajoz, Hospital Infanta Cristina , Badajoz , Spain
| | - F J Llorca
- k Facultad de Medicina, Universidad de Cantabria , Santander , Spain
| | - A Asunsolo
- l Departamento de Cirugía, Ciencias Médicas y Sociales, Facultad de Medicina y Ciencias de la Salud , Universidad de Alcalá Campus Científico-Tecnológico , Alcala de Henares , Spain
| | - P Sánchez
- m Facultad de Medicina , Universidad de Málaga , Málaga , Spain
| | - P R Gutiérrez
- n Servicio de Urología (Complejo Hospitalario Universitario de Canarias, CHUC) y Departamento de Cirugía (Universidad de La Laguna, ULL) San Cristóbal de La Laguna , Tenerife , Spain
| | - A Fernández
- o Departamento de Ciencias Biomédicas Básicas, Facultad de Ciencias Biomédicas , Universidad Europea de Madrid , Madrid , Spain
| | - M T de Jesús
- p Facultad de Medicina, Universidad Rey Juan Carlos , Madrid , Spain
| | - L Martínez Alarcón
- a International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante") , Murcia , Spain
- c Transplant Unit, Surgery Service , IMIB - Virgen de la Arrixaca University Hospital , Murcia , Spain
| | - A Lana
- q Facultad de Medicina y Ciencias de la Salud, Área de Medicina Preventiva y Salud Pública , Universidad de Oviedo , Oviedo , Spain
| | - L Fuentes
- r Departamento de Farmacología y Fisiología Facultad de Ciencias de la Salud y del Deporte , Universidad de Zaragoza , Huesca , Spain
| | - J R Hernández
- s Facultad de Medicina, Universidad de las Palmas de Gran Canaria , Las Palmas de Gran Canaria , Spain
| | - J Virseda
- t Facultad de Medicina, Universidad de Castilla La Mancha , Albacete , Spain
| | - J Yelamos
- u Department of Immunology , Hospital del Mar , Barcelona , Spain
| | - J A Bondía
- m Facultad de Medicina , Universidad de Málaga , Málaga , Spain
| | - A M Hernández
- v Endocrinology and Nutrition Service , Hospital Clínico Universitario Virgen de la Arrixaca, El Palmar, Servicio Murciano de Salud , Murcia , Spain
| | - M A Ayala
- w Hospital Regional de Alta Especialidad del Bajío , León , Mexico
- x HGSZ No. 10 del Instituto Mexicano del Seguro Social Delegación Guanajuato , Guanajuato , Mexico
| | - P Ramírez
- a International Collaborative Donor Project ("Proyecto Colaborativo Internacional Donante") , Murcia , Spain
- b Department of Surgery, Paediatrics, Obstetrics and Gynaecology , University of Murcia , Murcia , Spain
- c Transplant Unit, Surgery Service , IMIB - Virgen de la Arrixaca University Hospital , Murcia , Spain
- d Regional Transplant Centre , Consejería de Sanidad y Consumo de la Región de Murcia , Murcia , Spain
| | - P Parrilla
- b Department of Surgery, Paediatrics, Obstetrics and Gynaecology , University of Murcia , Murcia , Spain
- c Transplant Unit, Surgery Service , IMIB - Virgen de la Arrixaca University Hospital , Murcia , Spain
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Ríos A, López-Navas A, Gutiérrez PR, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Fernández A, de Jesús MT, Martínez Alarcón L, Lana A, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Hernández AM, Ayala MA, Flores-Medina J, Carrillo J, Sánchez Á, Ramírez P, Parrilla P. Sensitization Toward Organ Donation Among Medical Students in Spanish Regions With More Than 50 Donors Per Million Population. Transplant Proc 2019; 51:261-264. [PMID: 30879516 DOI: 10.1016/j.transproceed.2018.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/23/2018] [Indexed: 12/24/2022]
Abstract
The awareness of organ donation among health professionals is important at the time of transplant promotion. In this sense, the training and awareness of the professionals in training is fundamental. OBJECTIVE To analyze the differences in the attitude toward organ donation and the factors that condition it among medical students of regions with donation rates >50 donors per million population (pmp) with respect to those with rates <40 donor pmp. METHOD Population under study: medical students in Spanish universities. Database of the Collaborative International Donor Project, stratified by geographic area and academic course. The completion was anonymous and self-administered. Groups under study: Group 1 (n = 1136): students in universities of regions with >50 donors pmp. Group 2 (n = 2018): university students in regions with <40 donors pmp. Assessment instrument: attitude questionnaire for organ donation for transplant PCID-DTO-Ríos. RESULTS The attitude toward organ donation for transplantation is similar among students from the autonomous communities with >50 donors pmp and with <40 donors pmp. In group 1, 79% (n = 897) of students are in favor compared with 81% (n = 1625) of group 2 (P=.29). The psychosocial profile toward donation is similar in both groups relating to the following variables (P < .05): sex, having discussed transplantation with family and as a couple, considering the possibility of needing a transplant, involvement in prosocial activities, attitude toward the manipulation of corpses, knowledge of the brain death concept, and religion. CONCLUSIONS The awareness of organ donation in Spanish medical students is quite homogeneous and is not related to the local donation rates of each region.
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Affiliation(s)
- A Ríos
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics, y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB-Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain; Regional Transplant Centre, Consejería de Sanidad y Consumo de la Región de Murcia, Murcia, Spain.
| | - A López-Navas
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Department of Psychology, Catholic University of Murcia (UCAM), Murcia, Spain
| | - P R Gutiérrez
- Servicio de Urología (Complejo Hospitalario Universitario de Canarias, CHUC) y Departamento de Cirugía (Universidad de La Laguna, ULL) San Cristóbal de La Laguna, Tenerife, Spain
| | - F J Gómez
- Universidad de Granada, Granada, Spain
| | - J Iriarte
- Universidad de Navarra, Navarra, Spain
| | - R Herruzo
- Universidad Autónoma de Madrid, Madrid, Spain
| | - G Blanco
- Servicio de Cirugía HBP y Trasplante Hepático, Complejo Hospitalario Universitario de Badajoz, Hospital Infanta Cristina, Badajoz, Spain
| | - F J Llorca
- Universidad de Cantabria, Santander, Spain
| | - A Asunsolo
- Departamento de Cirugía, Ciencias Médicas y Sociales, Facultad de Medicina y Ciencias de la Salud, Universidad de Alcalá Campus Científico-Tecnológico, Alcala de Henares, Madrid, Spain
| | - P Sánchez
- Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - A Fernández
- Servicio de Urología (Complejo Hospitalario Universitario de Canarias, CHUC) y Departamento de Cirugía (Universidad de La Laguna, ULL) San Cristóbal de La Laguna, Tenerife, Spain
| | - M T de Jesús
- Departamento de Ciencias Biomédicas Básicas, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, Spain
| | - L Martínez Alarcón
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Transplant Unit, Surgery Service, IMIB-Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
| | - A Lana
- Universidad Rey Juan Carlos, Madrid, Spain
| | - L Fuentes
- Facultad de Medicina y Ciencias de la Salud, Área de Medicina Preventiva y Salud Pública, Universidad de Oviedo, Oviedo, Spain
| | - J R Hernández
- Departamento de Farmacología y Fisiología Facultad de Ciencias de la Salud y del Deporte, Universidad de Zaragoza, Huesca, Spain
| | - J Virseda
- Universidad de las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - J Yelamos
- Universidad de Castilla La Mancha, Albacete, Spain
| | - J A Bondía
- Department of Immunology, Hospital del Mar, Barcelona, Spain
| | - A M Hernández
- Endocrinology and Nutrition Service, Hospital Clínico Universitario Virgen de la Arrixaca, El Palmar, Servicio Murciano de Salud, Murcia, Spain
| | - M A Ayala
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Hospital Regional de Alta Especialidad del Bajío, León, Guanajuato, México; Hospital Regional no. 58 del IMSS, Delegación Guanajuato, México; Escuela de Medicina de la Universidad de Quetzalcoatl en Irapuato, Irapuato, México
| | - J Flores-Medina
- Department of Psychology, Catholic University of Murcia (UCAM), Murcia, Spain
| | - J Carrillo
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics, y Gynaecology, University of Murcia, Murcia, Spain
| | - Á Sánchez
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain
| | - P Ramírez
- Proyecto Colaborativo Internacional Donante (International Collaborative Donor Project), Murcia, Spain; Department of Surgery, Paediatrics, Obstetrics, y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB-Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain; Regional Transplant Centre, Consejería de Sanidad y Consumo de la Región de Murcia, Murcia, Spain
| | - P Parrilla
- Department of Surgery, Paediatrics, Obstetrics, y Gynaecology, University of Murcia, Murcia, Spain; Transplant Unit, Surgery Service, IMIB-Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
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Ríos A, López-Navas A, Gutiérrez P, Gómez F, Iriarte J, Herruzo R, Blanco G, Llorca F, Asunsolo A, Sánchez P, Fernández A, de Jesús M, Martínez Alarcón L, Lana A, Fuentes L, Hernández J, Virseda J, Yelamos J, Bondía J, Hernández A, Ayala M, Flores-Medina J, Carrillo J, Sánchez Á, Ramírez P, Parrilla P. Do Religious Factors Influence the Attitude Toward Organ Donation Among Medical Students? A Spanish Multicenter Study. Transplant Proc 2019; 51:250-252. [DOI: 10.1016/j.transproceed.2018.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/24/2018] [Accepted: 11/26/2018] [Indexed: 11/30/2022]
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10
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Ríos A, López-Navas A, López-López A, Gómez FJ, Iriarte J, Herruzo R, Blanco G, Llorca FJ, Asunsolo A, Sánchez P, Gutiérrez PR, Fernández A, de Jesús MT, Alarcón LM, del Olivo M, Fuentes L, Hernández JR, Virseda J, Yelamos J, Bondía JA, Hernández AM, Ayala MA, Ramírez P, Parrilla P. Do Spanish Medical Students Understand the Concept of Brain Death? Prog Transplant 2018; 28:77-82. [DOI: 10.1177/1526924817746687] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objective: To analyze the level of understanding of the brain death concept among medical students in universities in Spain. Methods: This cross-sectional sociological, interdisciplinary, and multicenter study was performed on 9598 medical students in Spain. The sample was stratified by geographical area and academic year. A previously validated self-reported measure of brain death knowledge (questionnaire Proyecto Colaborativo Internacional Donante sobre la Donación y Transplante de Organos) was completed anonymously by students. Results: Respondents completed 9275 surveys for a completion rate of 95.7%. Of those, 67% (n = 6190) of the respondents understood the brain death concept. Of the rest, 28% (n = 2652) did not know what it meant, and the remaining 5% (n = 433) believed that it did not mean that the patient was dead. The variables related to a correct understanding of the concept were: (1) being older ( P < .001), (2) studying at a public university ( P < .001), (3) year of medical school ( P < .001), (4) studying at one of the universities in the south of Spain ( P = .003), (5) having discussed donation and transplantation with the family ( P < .001), (6) having spoken to friends about the matter ( P < .001), (7) a partner’s favorable attitude toward donation and transplantation ( P < .001), and (8) religious beliefs ( P < .001). Conclusions: Sixty-seven percent of medical students know the concept of brain death, and knowledge improved as they advanced in their degree.
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Affiliation(s)
- Antonio Ríos
- International Collaborative Donor Project (“Proyecto Colaborativo Internacional Donante”), Murcia, Spain
- Department of Surgery, Paediatrics, Obstetrics and Gynaecology, University of Murcia, Murcia, Spain
- Transplant Unit, Surgery Service, IMIB—Virgen de la Arrixaca University Hospital, Murcia, Spain
- Regional Transplant Centre, Consejería de Sanidad y Consumo, Murcia, Spain
| | - A. López-Navas
- International Collaborative Donor Project (“Proyecto Colaborativo Internacional Donante”), Murcia, Spain
- Department of Psychology, Universidad Católica San Antonio (UCAM), Murcia, Spain
| | - A. López-López
- San Juan University Hospital of Alicante, Alicante, Spain
| | | | | | - R. Herruzo
- Universidad Autónoma de Madrid, Madrid, Spain
| | - G. Blanco
- Liver Transplant Unit, Hospital Infanta Cristina, Badajoz, Spain
| | | | - A. Asunsolo
- Department of Surgery, Universidad de Alcalá de Henares, Madrid, Spain
| | - P. Sánchez
- Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - P. R. Gutiérrez
- Department of Surgery, Universidad de La Laguna, Tenerife, Spain
| | - A. Fernández
- Departamento de Ciencias Biomédicas Básicas, Universidad Europea de Madrid, Madrid, Spain
| | | | - L. Martínez Alarcón
- International Collaborative Donor Project (“Proyecto Colaborativo Internacional Donante”), Murcia, Spain
- Transplant Unit, Surgery Service, IMIB—Virgen de la Arrixaca University Hospital, Murcia, Spain
| | - M. del Olivo
- Medicine Faculty, Universidad de Oviedo, Oviedo, Spain
| | - L. Fuentes
- Department of Pharmacology and Physiology, Universidad de Zaragoza, Huesca, Spain
| | - J. R. Hernández
- Universidad de las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Islas Canarias, Spain
| | - J. Virseda
- Universidad de Castilla La Mancha, Albacete, Spain
| | - J. Yelamos
- Department of Immunology, Hospital del Mar, Barcelona, Spain
| | - J. A. Bondía
- Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - A. M. Hernández
- Endocrinology and Nutrition Service, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
| | - M. A. Ayala
- Hospital Regional de Alta Especialidad del Bajío, León, Guanajuato, Mexico
- HGSZ No. 10 del Instituto Mexicano del Seguro Social Delegación Guanajuato, Guanajuato, Mexico
| | - P. Ramírez
- International Collaborative Donor Project (“Proyecto Colaborativo Internacional Donante”), Murcia, Spain
- Department of Surgery, Paediatrics, Obstetrics and Gynaecology, University of Murcia, Murcia, Spain
- Transplant Unit, Surgery Service, IMIB—Virgen de la Arrixaca University Hospital, Murcia, Spain
- Regional Transplant Centre, Consejería de Sanidad y Consumo, Murcia, Spain
| | - P. Parrilla
- Department of Surgery, Paediatrics, Obstetrics and Gynaecology, University of Murcia, Murcia, Spain
- Transplant Unit, Surgery Service, IMIB—Virgen de la Arrixaca University Hospital, Murcia, Spain
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Accordino SR, Malaspina DC, Rodriguez Fris JA, Alarcón LM, Appignanesi GA. Temperature dependence of the structure of protein hydration water and the liquid-liquid transition. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 85:031503. [PMID: 22587099 DOI: 10.1103/physreve.85.031503] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/12/2012] [Indexed: 05/31/2023]
Abstract
We study the temperature dependence of the structure and orientation of the first hydration layers of the protein lysozyme and compare it with the situation for a model homogeneous hydrophobic surface, a graphene sheet. We show that in both cases these layers are significantly better structured than bulk water. The geometrical constraint of the interface makes the water molecules adjacent to the surface lose one water-water hydrogen bond and expel the fourth neighbors away from the surface, lowering local density. We show that a decrease in temperature improves the ordering of the hydration water molecules, preserving such a geometrical effect. For the case of graphene, this favors an ice Ih-like local structuring, similar to the water-air interface but in the opposite way along the c axis of the basal plane (while the vicinal water molecules of the air interface orient a hydrogen atom toward the surface, the oxygens of the water molecules close to the graphene plane orient a lone pair in such a direction). In turn, the case of the first hydration layers of the lysozyme molecule is shown to be more complicated, but still displaying signs of both kinds of behavior, together with a tendency of the proximal water molecules to hydrogen bond to the protein both as donors and as acceptors. Additionally, we make evident the existence of signatures of a liquid-liquid transition (Widom line crossing) in different structural parameters at the temperature corresponding to the dynamic transition incorrectly referred to as "the protein glass transition."
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Affiliation(s)
- S R Accordino
- Sección Fisicoquímica INQUISUR-UNS-CONICET and Departamento de Química, Universidad Nacional del Sur, Bahía Blanca, Argentina
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12
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Schulz EP, Alarcón LM, Appignanesi GA. Behavior of water in contact with model hydrophobic cavities and tunnels and carbon nanotubes. Eur Phys J E Soft Matter 2011; 34:114. [PMID: 22015681 DOI: 10.1140/epje/i2011-11114-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 09/19/2011] [Indexed: 05/31/2023]
Abstract
By means of molecular dynamics simulations we analyze the behavior of water in contact with model hydrophobic cavities and tunnels. We study the hydration and filling propensity of cavities and tunnels carved in alkane monolayers and, for comparison, we also study single-walled carbon nanotubes of similar size. Our results will determine the dependence of the filling propensity as a function of cavity size while revealing the dynamical nature of the process with alternation of filled and dry states. Concerning the tunnels built across the monolayer, we shall show that the minimum diameter in order to get filled is about twice as large as that for the carbon nanotubes, thus evidencing a more hydrophobic behavior. The existence of water-water hydrogen bonds, a necessary condition for penetration, will also be made evident.
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Affiliation(s)
- E P Schulz
- Sección Fisicoquímica, INQUISUR-UNS-CONICET and Departamento de Química, Universidad Nacional del Sur, Avenida Alem 1253, 8000-Bahía Blanca, Argentina
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13
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Malaspina DC, Schulz EP, Alarcón LM, Frechero MA, Appignanesi GA. Structural and dynamical aspects of water in contact with a hydrophobic surface. Eur Phys J E Soft Matter 2010; 32:35-42. [PMID: 20524031 DOI: 10.1140/epje/i2010-10594-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 02/12/2010] [Accepted: 04/19/2010] [Indexed: 05/29/2023]
Abstract
By means of molecular dynamics simulations we study the structure and dynamics of water molecules in contact with a model hydrophobic surface: a planar graphene-like layer. The analysis of the distributions of a local structural index indicates that the water molecules proximal to the graphene layer are considerably more structured than the rest and, thus, than the bulk. This structuring effect is lost in a few angstroms and is basically independent of temperature for a range studied comprising parts of both the normal liquid and supercooled states (240K to 320K). In turn, such structured water molecules present a dynamics that is slower than the bulk, as a consequence of their improved interactions with their first neighbors.
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Affiliation(s)
- D C Malaspina
- Departamento de Química, Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Avenida Alem 1253, 8000 Bahía Blanca, Argentina
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14
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Alarcón LM, Frechero MA, Montani RA, Appignanesi GA. Determining the heterogeneity in time of the dynamics within a slowly relaxing region of a supercooled liquid: Role of sharp relaxation events. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:026127. [PMID: 19792220 DOI: 10.1103/physreve.80.026127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 06/24/2009] [Indexed: 05/28/2023]
Abstract
Supercooled liquids have been shown to be dynamically heterogeneous with different regions of the system presenting dynamics that vary from each other even by orders of magnitude. Computer simulations have confirmed such a picture by detecting that the mobile particles in model glass formers are not homogeneously distributed within the system but arranged in clusters. More recently, the dynamics of small systems has been characterized by demonstrating that their structural relaxation is not homogeneous in time, in the sense that it does not evolve gradually but it is signed by rapid bursts of mobility characterized by relative compact clusters of mobile particles. These events (which have been named d clusters) are fast and sparse and trigger the transitions the system experiences between metabasins (MB) of its potential-energy surface. The MB residence times are much larger than the time scales of occurrence of the d clusters, and it has been suggested that the events that occur within them scarcely contribute to the structural relaxation of the system. Thus, the picture of glassy relaxation that emerges would indicate that at any time a supercooled liquid may present different spatial regions, each one characterized by different structural relaxation times. In turn, each of such regions would not relax smoothly or gradually but by means of sporadic sharp relaxation events. Here, we assess for a model glass former the relative relevance of the MB exploration events and of the d clusters both in small systems and within regions of large systems, to show that the structural relaxation at the region level is indeed extremely heterogeneous in time and utterly governed by the latter.
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Affiliation(s)
- L M Alarcón
- Sección Fisicoquímica, INQUISUR-UNS-CONICET and Departamento de Química, Universidad Nacional del Sur, Avenida Alem 1253, 8000 Bahía Blanca, Argentina
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15
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Rodriguez Fris JA, Alarcón LM, Appignanesi GA. Do short-time fluctuations predict the long-time dynamic heterogeneity in a supercooled liquid? Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:011502. [PMID: 17677445 DOI: 10.1103/physreve.76.011502] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 05/26/2007] [Indexed: 05/16/2023]
Abstract
Recent investigations have demonstrated that the short-time fluctuations in a supercooled liquid can be used as predictors of the long-time dynamic propensity (that is, the regions of the sample with enhanced tendency to be mobile within time scales on the order of the alpha -relaxation time). This could mean that the long-time dynamics (the actual mobility of the particles at such long times) would be implicit in the short-time dynamics or else, that the long-time dynamic propensity [as defined in A. Widmer-Cooper and P. Harrowell, Phys. Rev. Lett. 96, 185701 (2006)], while providing a measure of the degree of jamming of the local structure, would only be sensitive to the short time behavior. The first scenario is in clear disagreement with our recent finding that the influence of the local structure on dynamics (as determined by the propensity for motion) is only local in time, fading out at times close to the metabasin lifetime, much before the alpha -relaxation time. Thus, in this work we show that the short-time fluctuations in supercooled liquids do in fact represent precursors to the dynamics at intermediate times commensurate with the metabasin lifetime (being thus able to predict the regions of the sample that will present high propensity for motion at such stage) but that the dynamical behavior at later times of the alpha relaxation is unpredictable, in agreement with a metabasin random walk scenario.
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Affiliation(s)
- J A Rodriguez Fris
- Fisicoquímica, Departamento de Química, Universidad Nacional del Sur, Avenida Alem 1253, 8000 Bahía Blanca, Argentina
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Frechero MA, Alarcón LM, Schulz EP, Appignanesi GA. Connections between structural jamming, local metabasin features, and relaxation dynamics in a supercooled glassy liquid. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 75:011502. [PMID: 17358155 DOI: 10.1103/physreve.75.011502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Indexed: 05/14/2023]
Abstract
Dynamics in glass-forming liquids in the supercooled regime vary considerably from one point of the sample to another suggesting the existence of regions with different degrees of jamming. In fact, the existence of relatively compact regions with particles with an enhanced propensity for motion has been detected in model glassy systems. In turn, the structural relaxation has been shown to be accomplished by means of a series of fast transitions between metabasins in the potential energy landscape involving the collective motion of a substantial number of particles arranged in relatively compact clusters (democratic clusters or d clusters). In this work we shall complete this picture by identifying the connections between local structural jamming, metabasin confining strength, and d clusters. Thus we shall demonstrate that the degree of jamming of the local structure dictates the confining strength of the local metabasin and that the local high propensity regions and the d clusters are not only similar in nature but that they share a significant amount of particles.
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Affiliation(s)
- M A Frechero
- Fisicoquímica, Departamento de Química, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina
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Appignanesi GA, Alarcón LM, Rodríguez Fris JA, Frechero MA, Montani RA. Activated dynamics and timescale separation within the landscape paradigm: signature of complexity, diversity and glassiness. Biophys Chem 2005; 115:129-34. [PMID: 15752594 DOI: 10.1016/j.bpc.2004.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Revised: 10/29/2004] [Accepted: 12/10/2004] [Indexed: 10/26/2022]
Abstract
The landscape paradigm has become a widespread picture within the realm of complex systems. Complex systems include a great variety of systems, ranging from glasses to biopolymers, which display a common dynamical behavior. Within this framework, the dynamics of a such a system can be envisioned as the search it performs on its (potential energy) landscape. This approach rests on the belief that the relaxation behavior depends only on generic features, irrespective of specific details and lies on the validity of a timescale separation scenario computationally corroborated but not properly validated yet form first principles. In this work we shall show that the prevalence of activated dynamics over other kinds of mechanisms determines the emergence of complex dynamical behavior. Thus, complexity and diversity are not intrinsic properties of a system but depend on the kind of exploration of the landscape. We shall focus mainly on an ample generic context (complex hierarchical systems which have been used as models of glasses, spin glasses and biopolymers) and a specific one (model glass formers). For the last case we shall be able to reveal (in mechanistic terms) the microscopic rationale for the occurrence of timescale separation. Furthermore, we shall explore the connections between these two up to now mostly unrelated contexts and the relation to a variational principle, and we shall reveal the conditions for the applicability of the landscape approach.
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Affiliation(s)
- G A Appignanesi
- Departamento de Química, Universidad Nacional del Sur, Bahía Blanca, Argentina.
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