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Santiago J, Karl G, Florez C, Molina Y, Castro J, Hurtado A, García V. Infectious endarteritis in aortic coarctation: two spectra of an infrequent disease. Rev Paul Pediatr 2023; 42:e2023084. [PMID: 38126604 PMCID: PMC10742369 DOI: 10.1590/1984-0462/2024/42/2023084] [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: 05/15/2023] [Accepted: 09/14/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE To describe two different degrees of clinical commitment and results in the evolution of infectious endarteritis in patients without a previous diagnosis of aortic coarctation. CASE DESCRIPTION Two male patients aged 13 and 9 years old were admitted. The first due to a fever for 2 months, which started after dental cleaning, and the second due to high blood pressure, both patients with asthenia and weight loss. In the first case, the transthoracic echocardiogram showed aortic coarctation, and the transesophageal echocardiogram showed the presence of vegetations in the post-coarctation area, without pseudoaneurysms, with blood culture positive for Streptococcus mitis. This patient was treated for six weeks with crystalline penicillin, resolving the infection without complications. The second case was assessed for high blood pressure with a history of fever, and was treated with antibiotics. When performing a transthoracic echocardiogram, aortic coarctation was observed with a saccular image classified as a pseudoaneurysm by angiography and tomography. Blood culture was negative, and the patient developed an episode of hematemesis whose initial etiology could not be determined. Before surgical repair, he had a second episode of copious hematemesis with hypovolemic shock and death. COMMENTS We need to have a high index of clinical suspicion to establish the diagnosis of aortic coarctation complicated by endarteritis and start the appropriate antibiotic treatment, always maintaining surveillance for the early detection of pseudoaneurysms.
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Affiliation(s)
- Justo Santiago
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Gabriela Karl
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Claudia Florez
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Yudisay Molina
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Javier Castro
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Alexandra Hurtado
- Cardiovascular Foundation of Colombia, Bucaramanga, Santander, Colombia
| | - Valeria García
- Santander University Hospital, Bucaramanga, Santander, Colombia
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Salgado-Almario J, Vicente M, Molina Y, Martinez-Sielva A, Vincent P, Domingo B, Llopis J. Calcium, contraction, and hemodynamic alterations induced by arrhythmogenic drugs in the zebrafish larvae. Cardiovasc Res 2022. [DOI: 10.1093/cvr/cvac066.112] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – EU funding. Main funding source(s): MCIN/AEI/ 10.13039/501100011033 and “ERDF A way of making Europe” by the European Union
Background
Ca2+ ion is pivotal in excitation-contraction coupling. The dysregulation of Ca2+ fluxes is at the core of inherited and acquired arrhythmias. In recent years zebrafish have become an attractive vertebrate model to study heart development, cardiotoxicity, and heart diseases. We recently reported that the transgenic zebrafish line Tg(myl7:Twitch-4) expressing the ratiometric Ca2+ indicator Twitch-4 in the heart, allowed imaging Ca2+ transients (CaT) simultaneously with heart contraction in zebrafish larvae, thus maintaining the physiological mechano-electrical feedback.
Purpose
This study aimed to detect subtle disturbances in Ca2+ cycling, contractility, and hemodynamics induced by arrhythmogenic drugs in zebrafish larvae.
Methods
We have used the zebrafish transgenic line Tg(myl7:Twitch-4) and a custom software to acquire and analyze fluorescence emission ratio images of the heart. Larvae of 3- and 5-days post-fertilization (dpf) were incubated with arrhythmogenic drugs, and their effects on the systolic and diastolic Ca2+ and the CaT amplitude in the atrium and ventricle were determined. As the ventricular diameter was assessed in the same fluorescence images, a simultaneous, real-time, measurement of contraction correlated with Ca2+ was obtained. The systolic and diastolic areas, measured independently, were used to estimate hemodynamic parameters.
Results
Dofetilide caused time-dependent bradycardia and ultimately a 2:1 arrhythmia in 3 and 5 dpf larvae, with an increase in the CaT amplitude. the ejection fraction and the stroke volume increased, but the cardiac output decreased due to the low heart rate (2:1 arrhythmia). The T-type Ca2+ channel antagonist ML218 induced bradycardia and decreased systolic and diastolic Ca2+ levels in 3 dpf larvae, but the CaT amplitude did not change. Interestingly, some larvae (3 out of 14) displayed a progressive lengthening of the time between the start of atrial and ventricular CaT, analogous to increased PR interval of the electrocardiogram, until a ventricular systole failed. This is reminiscent of a second-degree atrioventricular block in humans. At higher ML218 concentration, a 2:1 arrhythmia was observed and increased ventricular CaT amplitude in all larvae.
Conclusions
We characterized Ca2+ changes induced by arrhythmogenic drugs and correlated them with contractility and hemodynamic parameters. The zebrafish line Tg(myl7:Twitch-4) allowed investigating drug-induced arrhythmias in this animal model with unprecedented detail. This transgenic line will serve to screen cardiotoxicity during drug development and to study conduction and rhythm defects in zebrafish, and their correlation with human disease.
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Affiliation(s)
- J Salgado-Almario
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
| | - M Vicente
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
| | - Y Molina
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
| | - A Martinez-Sielva
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
| | - P Vincent
- Sorbonne University, CNRS , Paris , France
| | - B Domingo
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
| | - J Llopis
- University of Castilla-La Mancha, Faculty of Medicine , Albacete , Spain
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Sánchez-Díaz CT, Strayhorn S, Tejeda S, Vijayasiri G, Rauscher GH, Molina Y. What mediates the racial/ethnic disparity in psychosocial stress among breast cancer patients? Cancer Causes Control 2021; 32:357-367. [PMID: 33559770 PMCID: PMC7946668 DOI: 10.1007/s10552-021-01392-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Prior studies have observed greater levels of psychosocial stress (PSS) among non-Hispanic (nH) African American and Hispanic women when compared to nH White patients after a breast cancer diagnosis. We aimed to determine the independent and interdependent roles of socioeconomic position (SEP) and unmet support in the racial disparity in PSS among breast cancer patients. METHODS Participants were recruited from the Breast Cancer Care in Chicago study (n = 989). For all recently diagnosed breast cancer patients, aged 25-79, income, education, and tract-level disadvantage and affluence were summed to create a standardized socioeconomic position (SEP) score. Three measures of PSS related to loneliness, perceived stress, and psychological consequences of a breast cancer diagnosis were defined based on previously validated scales. Five domains of unmet social support needs (emotional, spiritual, informational, financial, and practical) were defined from interviews. We conducted path models in MPlus to estimate the extent to which PSS disparities were mediated by SEP and unmet social support needs. RESULTS Black and Hispanic patients reported greater PSS compared to white patients and greater unmet social support needs (p = 0.001 for all domains). Virtually all of the disparity in PSS could be explained by SEP. A substantial portion of the mediating influence of SEP was further transmitted by unmet financial and practical needs among Black patients and by unmet emotional needs for Hispanic patients. CONCLUSIONS SEP appeared to be a root cause of the racial/ethnic disparities in PSS within our sample. Our findings further suggest that different interventions may be necessary to alleviate the burden of SEP for nH AA (i.e., more financial support) and Hispanic patients (i.e., more emotional support).
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Affiliation(s)
- C T Sánchez-Díaz
- Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, 1603 West Taylor Street, Chicago, IL, 60612, USA.
| | - S Strayhorn
- Institute for Health Research and Policy, University of Illinois at Chicago, Chicago, USA
| | - S Tejeda
- Institute for Health Research and Policy, University of Illinois at Chicago, Chicago, USA
| | - G Vijayasiri
- Institute for Health Research and Policy, University of Illinois at Chicago, Chicago, USA
| | - G H Rauscher
- Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, 1603 West Taylor Street, Chicago, IL, 60612, USA
- Division of Community Health Sciences, School of Public Health, University of Illinois at Chicago, Chicago, USA
| | - Y Molina
- Division of Community Health Sciences, School of Public Health, University of Illinois at Chicago, Chicago, USA
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Diaz Gavela A, Del Cerro E, Marcos F, Counago F, Molina Y, Sanz I, Henríquez A, Hornedo J. EP-1285: Immediate breast reconstruction followed by adjuvant radiotherapy. Aesthetics and Quality of life. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)31595-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
<span>Los trastornos del sueño en el adulto mayor son un problema manifestado con frecuencia, que afecta la calidad de vida y tiene impacto en los costos y el cuidado de salud. La actual forma de manejo de estos problemas se relaciona con prescripciones de fármacos, los cuales tienen efectos secundarios y aumenta su vulnerabilidad. En este contexto, el objetivo de esta investigación es evaluar la efectividad de una intervención cognitivo y conductual, que pretende mejorar el sueño mediante el cambio de los hábitos deficientes, así como el desafío de los pensamientos, las actitudes y las creencias negativas acerca del mismo. El método incluyó intervenciones conductivo-conductuales grupales, con evaluaciones pre y post intervención. Los resultados indican una media de 9 (Pittsburgh) al inicio del programa y 4.9 al finalizar. Se concluye que la intervención a corto plazo consigue cambios significativos en hábitos e higiene del sueño. Esta investigación orienta a los profesionales de enfermería en la aplicación de estrategias hacia el bienestar del adulto mayor y el desarrollo de la disciplina en el marco del fortalecimiento de cuidados esenciales y fundamentales en procesos vitales.</span>
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Molina Y, San Miguel LG, Tamayo L, Sanchez-Diaz C, Robledo C, Peña K, Lucio A, Hernandez O, Arroyo J, Medina M, Coronado N, Irma V. Empowering Latinas to Obtain Breast Cancer Screenings: Comparing Intervention Effects, Part 2. Cancer Epidemiol Biomarkers Prev 2018. [DOI: 10.1158/1055-9965.epi-18-0048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
We compare the effects of breast cancer education and empowerment approaches on non-adherent Latinas' breast health behaviors and dissemination of health information. Methods: The setting for this ongoing, quasi-experimental trial is two Latino, lower income communities in Chicago. Women were recruited via two community-based organizations and snowball sampling. Eligibility criteria were: 1) age of 52–74; 2) lack of screening within past 2 years; 3) no previous breast cancer diagnosis; and, 4) no health volunteerism experience. Women were assigned to a three week group intervention (3 2 hour sessions). The education intervention is administered in East Side/South Chicago and the empowerment intervention is administered in Pilsen/Little Village to avoid contamination effects. The education intervention has 3 sessions focused on early detection and prevention (diet, physical activity). The empowerment intervention has 3 sessions focused on early detection, sharing information with family/friends, and health volunteerism. Navigation is provided if women wish to obtain mammograms. Three questionnaires are given at baseline, post-intervention, and a 6 month follow-up. Results: Among our 68 participants (34 education; 34 empowerment), 87% were born in Mexico; 59% had <9th grade education; 52% had a median household income of <$10K; and, 51% were uninsured. The average age was 61.21 (SD = 6.20). Relative to education participants, more empowerment participants have scheduled mammograms (94% vs. 74%; P = 0.05) and obtained mammograms (77% vs. 38%, P = 0.001). Empowerment participant also spoke to more individuals about breast health relative to education participants (M = 6.24, SD = 5.30 vs. M = 3.00, SD = 3.04, P = 0.003). A greater proportion of engagement participants also spoke about specific types of breast cancer screening (58% vs. 38%, P = 0.01) and discussed breast cancer across multiple settings (58% vs. 24%, P = 0.003). Discussion: The empowerment approach may be particularly effective in changing non-adherent Latinas' screening behaviors and promoting them to become agents of change in their communities. Limitations concern generalizability due a non-probability based sample, and limited ability for causal inferences due to a lack of randomization.
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Reyes Y, Paoli M, Camacho N, Molina Y, Santiago J, Lima-Martínez MM. Epicardial adipose tissue thickness in children and adolescents with cardiometabolic risk factors. ACTA ACUST UNITED AC 2015; 63:70-8. [PMID: 26654426 DOI: 10.1016/j.endonu.2015.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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: 06/15/2015] [Revised: 09/07/2015] [Accepted: 09/08/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To assess the relationship of epicardial adipose tissue (EAT) thickness with cardiometabolic risk factors (CRFs) in children and adolescents. METHODS Seventy-seven subjects of both sexes aged 7-18 years were selected. Medical history, clinical parameters, and glucose, insulin, and lipid levels were collected. EAT thickness was measured using transthoracic echocardiography. Study subjects were divided into two groups based on whether they had less than two or two or more CRFs. RESULTS The group with two or more CRFs had higher EAT thickness, insulin, and HOMA-IR values (P<.05). EAT thickness showed a statistically significant positive correlation with body mass index (BMI) (r=0.561, P=.0001), waist circumference (r=.549, P=.0001), systolic blood pressure (SBP) (r=.256, P=.028), insulin (r=0.408, P=.0001), and HOMA-IR (r=.325, P=.005). However, these correlations were not significant after adjustment for BMI. The cut-off point for EAT thickness as predictor of two or more CRFs was 3.17mm. The risk (odds ratio) of having two or more CRFs if EAT thickness was >3.17mm was 3.1 (95% CI: 1.174-8.022). BMI was the independent variable that most affected EAT thickness and the presence of two or more CRFs. CONCLUSION In this group of children and adolescents, the relationship of EAT thickness with CRFs was found to be dependent on BMI.
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Affiliation(s)
- Yubriangel Reyes
- Unidad de Endocrinología, Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela
| | - Mariela Paoli
- Unidad de Endocrinología, Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela.
| | - Nolis Camacho
- Unidad de Nutrición, Crecimiento y Desarrollo Infantil, Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela
| | - Yudisay Molina
- Instituto de Investigaciones Cardiovasculares, Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela
| | - Justo Santiago
- Instituto de Investigaciones Cardiovasculares, Instituto Autónomo Hospital Universitario de los Andes, Mérida, Venezuela
| | - Marcos M Lima-Martínez
- Departamento de Ciencias Fisiológicas, Universidad de Oriente, Núcleo Bolívar, Ciudad Bolívar, Venezuela
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Abstract
Despite the increased interest in HIV/AIDS stigma and its negative effects on the health and social support of people living with HIV/AIDS (PLWHA), little attention has been given to its assessment among Latino gay/ bisexual men and transgender women (GBT) living with HIV/AIDS. The purpose of this paper is twofold: to develop a multidimensional assessment of HIV/AIDS stigma for Latino GBT living with HIV/AIDS, and to test whether such stigma is related to self-esteem, safe sex self-efficacy, social support, and alcohol, and drug use. The sample included 170 HIV+ Latino GBT persons. The results revealed three dimensions of stigma: internalized, perceived, and enacted HIV/AIDS stigma. Enacted HIV/AIDS stigma comprised two domains: generalized and romantic and sexual. Generalized enacted HIV/AIDS stigma was related to most outcomes. Internalized HIV/AIDS stigma mediated the associations between generalized enacted HIV/AIDS stigma and self-esteem and safe sex self-efficacy. In addition, romantic and sexual enacted HIV/AIDS stigma significantly predicted drug use. Perceived HIV/AIDS stigma was not associated with any outcome. These findings expand the understanding of the multidimensionality of stigma and the manner in which various features impact marginalized PLWHA.
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Affiliation(s)
- Y. Molina
- Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - J. Ramirez-Valles
- Community Health Sciences University of Illinois-Chicago, Chicago, IL, USA
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Molina Y, Harris RM, O'Donnell S. Brain organization mirrors caste differences, colony founding and nest architecture in paper wasps (Hymenoptera: Vespidae). Proc Biol Sci 2009; 276:3345-51. [PMID: 19553252 DOI: 10.1098/rspb.2009.0817] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The cognitive challenges that social animals face depend on species differences in social organization and may affect mosaic brain evolution. We asked whether the relative size of functionally distinct brain regions corresponds to species differences in social behaviour among paper wasps (Hymenoptera: Vespidae). We measured the volumes of targeted brain regions in eight species of paper wasps. We found species variation in functionally distinct brain regions, which was especially strong in queens. Queens from species with open-comb nests had larger central processing regions dedicated to vision (mushroom body (MB) calyx collars) than those with enclosed nests. Queens from advanced eusocial species (swarm founders), who rely on pheromones in several contexts, had larger antennal lobes than primitively eusocial independent founders. Queens from species with morphologically distinct castes had augmented central processing regions dedicated to antennal input (MB lips) relative to caste monomorphic species. Intraspecific caste differences also varied with mode of colony founding. Independent-founding queens had larger MB collars than their workers. Conversely, workers in swarm-founding species with decentralized colony regulation had larger MB calyx collars and optic lobes than their queens. Our results suggest that brain organization is affected by evolutionary transitions in social interactions and is related to the environmental stimuli group members face.
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Affiliation(s)
- Y Molina
- Animal Behavior Program, Department of Psychology, University of Washington, Seattle, WA 98195, USA.
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Molina Y, O'Donnell S. A developmental test of the dominance-nutrition hypothesis: linking adult feeding, aggression, and reproductive potential in the paperwaspMischocyttarusmastigophorus. ETHOL ECOL EVOL 2008. [DOI: 10.1080/08927014.2008.9522533] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Verma S, Molina Y, Lo YY, Cropp CB, Arai S, Nakano CM, Yanagihara R, Nerurkar VR. Role of Oxidative Stress in West Nile Virus (WNV)‐ induced Apoptosis. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1073-b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Saguna Verma
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - Y. Molina
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - Y. Y. Lo
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - C. B. Cropp
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - S. Arai
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - C. M. Nakano
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - R. Yanagihara
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
| | - V. R. Nerurkar
- Dept. of Trop MedicineUniv. of Hawaii3675 Kilauea AveHonoluluHI96816
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Cianelli R, Ferrer L, Bernales M, Miner S, Irarrázabal L, Molina Y. [Not Available]. Horiz Enferm 2006; 17:15-22. [PMID: 21197380 PMCID: PMC3011817] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND: Epidemiological characterization in Chile points to the feminization, pauperization and heterosexualization of the HIV epidemic, which indicates increased risk for socially disadvantaged women. When the use of substances is added to this, the vulnerability of this group in terms of HIV is magnified. OBJECTIVE: To describe the use of substances in socially disadvantaged women and to identify HIV/AIDS risk factors associated with the use or consumption of substances. MATERIAL AND METHOD: 52 women were interviewed as part of the project "Testing an HIV prevention intervention in Chilean women" GRANT # RO1 TW 006977. Socio-demographic and substance use variables are described through descriptive statistics, and the relationship between variables is analyzed using correlation tests. RESULTS: The results reveal a socio-demographic profile that places women in a vulnerable situation regarding transmission of HIV/AIDS, with high indices of substance use amplifying risk. CONCLUSIONS: These finding indicate the need for interventions focusing on HIV prevention in women that incorporate the risks associated with the consumption of substances.
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Affiliation(s)
- R. Cianelli
- PhD, Académico Escuela de Enfermería Pontificia Universidad Católica de Chile, Adjunt Professor University of Miami, University of Illinois at Chicago
| | - L Ferrer
- PhD, Académico Escuela de Enfermería Pontificia Universidad Católica de Chile, Adjunt Professor University of Miami, University of Illinois at Chicago
| | - M. Bernales
- MP, Académico Escuela de Enfermería Pontificia Universidad Católica de Chile
| | - S. Miner
- BSN, Académico Escuela de Enfermería Pontificia Universidad Católica de Chile
| | - L. Irarrázabal
- BSN, Académico Escuela de Enfermería Pontificia Universidad Católica de Chile
| | - Y. Molina
- Ps, Candidato Magíster Escuela de Psicología Pontificia Universidad Católica de Chile
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Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that synthesizes and catabolizes inositol. This study demonstrates inositol synthesis from glucose-6-phosphate via inositol-1-phosphate synthase and catabolism to glucuronic acid via inositol oxygenase in this organism. These inositol synthetic and catabolic pathways are regulated in opposition; repressing conditions for one are inducing conditions for the other. An inositol-requiring strain was generated by UV mutagenesis. Without inositol, this mutant strain undergoes 'inositol-less' death, during which time the phosphatidylinositol composition of the membranes decreases without alteration of the proportion of other phospholipids. The mutation on this strain results in no detectable inositol synthetic activity but normal (wild-type) inositol catabolic activity. This inositol-requiring mutant strain reverted at a high frequency. Classical genetic experiments revealed that the majority of the reverting mutations are at second sites. Interestingly, the revertants exhibited unusual morphological phenotypes when deprived of inositol, while provision of inositol restored wild-type morphology. Inositol metabolism is clearly important for growth and development of C. neoformans and may be involved in this organism's mechanism for survival as both a saprophyte in soil and a parasite in humans.
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Affiliation(s)
- Y Molina
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA
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Nagpal S, Ghosn C, DiSepio D, Molina Y, Sutter M, Klein ES, Chandraratna RA. Retinoid-dependent recruitment of a histone H1 displacement activity by retinoic acid receptor. J Biol Chem 1999; 274:22563-8. [PMID: 10428834 DOI: 10.1074/jbc.274.32.22563] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Targeted recruitment of histone acetyltransferase (HAT) activities by sequence-specific transcription factors, including the retinoic acid receptors (RARs) and retinoid X receptors (RXRs), has been proposed to lead to destabilization of nucleosomal cores by acetylation of core histones. However, biochemical evidence indicates that destabilization and depletion of linker H1 histones must also occur at the promoter regions of actively transcribing genes. Mechanisms by which nuclear receptors and other transcription factors affect the removal of histone H1 from transcriptionally silent chromatin have not been previously described. In this report, we show that RARs interact in a ligand-dependent manner with HMG-I, which is known to displace histone H1 from chromatin. We further show that HMG-I and a novel related protein, HMG-R, also interact with other transcription factors. Using sense and antisense constructs of HMG-I/R in transient transfection assays with a retinoid responsive reporter, we also demonstrate that HMG-I/R is important for retinoid dependent transcriptional activity of RAR. These findings suggest a step wise mechanism by which RARs and other transcription factors can cause a targeted unfolding of compact chromatin as a first step in transcriptional activation, which would then be followed by recruitment of HAT activity and subsequent events.
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Affiliation(s)
- S Nagpal
- Retinoid Research, Allergan Inc., Irvine, California 92713, USA.
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