HISTONE DEACETYLASE19 Controls Ovule Number Determination and Transmitting Tract Differentiation.

The gynoecium is critical for the reproduction of flowering plants as it contains the ovules and the tissues that foster pollen germination, growth, and guidance. These tissues, known as the reproductive tract (ReT), comprise the stigma, style, and transmitting tract (TT). The ReT and ovules originate from the carpel margin meristem (CMM) within the pistil. SHOOT MERISTEMLESS (STM) is a key transcription factor for meristem formation and maintenance. In all above-ground meristems, including the CMM, local STM downregulation is required for organ formation. However, how this downregulation is achieved in the CMM is unknown. Here, we have studied the role of HISTONE DEACETYLASE 19 (HDA19) in Arabidopsis (Arabidopsis thaliana) during ovule and ReT differentiation based on the observation that the hda19-3 mutant displays a reduced ovule number and fails to differentiate the TT properly. Fluorescence-activated cell sorting coupled with RNA-sequencing revealed that in the CMM of hda19-3 mutants, genes promoting organ development are downregulated while meristematic markers, including STM, are upregulated. HDA19 was essential to downregulate STM in the CMM, thereby allowing ovule formation and TT differentiation. STM is ectopically expressed in hda19-3 at intermediate stages of pistil development, and its downregulation by RNA interference alleviated the hda19-3 phenotype. Chromatin immunoprecipitation assays indicated that STM is a direct target of HDA19 during pistil development and that the transcription factor SEEDSTICK is also required to regulate STM via histone acetylation. Thus, we identified factors required for the downregulation of STM in the CMM, which is necessary for organogenesis and tissue differentiation.

Assessing the role of REM13, REM34 and REM46 during the transition to the reproductive phase in Arabidopsis thaliana.

REM (reproductive meristem) transcription factors have been proposed as regulators of plant reproductive development mainly based on their specific expression patterns in reproductive structures, but their roles are still largely unknown probably because of their redundancy. We selected three REM genes (REM13, REM34 and REM46) for functional analysis, based on their genome position and/or co-expression data.Our results suggest that these genes have a role in flowering time regulation and may modulate cell cycle progression. In addition, protein interaction experiments revealed that REM34 and REM46 interact with each other, suggesting that they might work cooperatively to regulate cell division during inflorescence meristem commitment.Previous attempts of using co-expression data as a guide for functional analysis of REMs were limited by the transcriptomic data available at the time. Our results uncover previously unknown functions of three members of the REM family of Arabidopsis thaliana and open the door to more comprehensive studies of the REM family, where the combination of co-expression analysis followed by functional studies might contribute to uncovering the biological roles of these proteins and the relationship among them.

The Importance of Cytokinins during Reproductive Development in Arabidopsis and Beyond.

Fertilization and seed formation are fundamental events in the life cycle of flowering plants. The seed is a functional unit whose main purpose is to propagate the plant. The first step in seed development is the formation of male and female gametophytes and subsequent steps culminate in successful fertilization. The detailed study of this process is highly relevant because it directly impacts human needs, such as protecting biodiversity and ensuring sustainable agriculture to feed the increasing world population. Cytokinins comprise a class of phytohormones that play many important roles during plant growth and development and in recent years, the role of this class of phytohormones during reproduction has become clear. Here, we review the role of cytokinins during ovule, pollen and seed formation at the genetic and molecular levels. The expansion of knowledge concerning the molecular mechanisms that control plant reproduction is extremely important to optimise seed production.

Cytokinin response factors integrate auxin and cytokinin pathways for female reproductive organ development.

The developmental programme of the pistil is under the control of both auxin and cytokinin. Crosstalk between these factors converges on regulation of the auxin carrier PIN-FORMED 1 (PIN1). Here, we show that in the triple transcription factor mutant cytokinin response factor 2 (crf2) crf3 crf6 both pistil length and ovule number were reduced. PIN1 expression was also lower in the triple mutant and the phenotypes could not be rescued by exogenous cytokinin application. pin1 complementation studies using genomic PIN1 constructs showed that the pistil phenotypes were only rescued when the PCRE1 domain, to which CRFs bind, was present. Without this domain, pin mutants resemble the crf2 crf3 crf6 triple mutant, indicating the pivotal role of CRFs in auxin-cytokinin crosstalk.

Live and let die: a REM complex promotes fertilization through synergid cell death in Arabidopsis.

Fertilization in flowering plants requires a complex series of coordinated events involving interaction between the male and female gametophyte. We report here molecular data on one of the key events underpinning this process - the death of the receptive synergid cell and the coincident bursting of the pollen tube inside the ovule to release the sperm. We show that two REM transcription factors, VALKYRIE (VAL) and VERDANDI (VDD), both targets of the ovule identity MADS-box complex SEEDSTICK-SEPALLATA3, interact to control the death of the receptive synergid cell. In vdd-1/+ mutants and VAL_RNAi lines, we find that GAMETOPHYTIC FACTOR 2 (GFA2), which is required for synergid degeneration, is downregulated, whereas expression of FERONIA (FER) and MYB98, which are necessary for pollen tube attraction and perception, remain unaffected. We also demonstrate that the vdd-1/+ phenotype can be rescued by expressing VDD or GFA2 in the synergid cells. Taken together, our findings reveal that the death of the receptive synergid cell is essential for maintenance of the following generations, and that a complex comprising VDD and VAL regulates this event.

Genetic insights into the modification of the pre-fertilization mechanisms during plant domestication.

Plant domestication is the process of adapting plants to human use by selecting specific traits. The selection process often involves the modification of some components of the plant reproductive mechanisms. Allelic variants of genes associated with flowering time, vernalization, and the circadian clock are responsible for the adaptation of crops, such as rice, maize, barley, wheat, and tomato, to non-native latitudes. Modifications in the plant architecture and branching have been selected for higher yields and easier harvests. These phenotypes are often produced by alterations in the regulation of the transition of shoot apical meristems to inflorescences, and then to floral meristems. Floral homeotic mutants are responsible for popular double-flower phenotypes in Japanese cherries, roses, camellias, and lilies. The rise of peloric flowers in ornamentals such as snapdragon and florists' gloxinia is associated with non-functional alleles that control the relative expansion of lateral and ventral petals. Mechanisms to force outcrossing such as self-incompatibility have been removed in some tree crops cultivars such as almonds and peaches. In this review, we revisit some of these important concepts from the plant domestication perspective, focusing on four topics related to the pre-fertilization mechanisms: flowering time, inflorescence architecture, flower development, and pre-fertilization self-incompatibility mechanisms.

CUP-SHAPED COTYLEDON1 (CUC1) and CUC2 regulate cytokinin homeostasis to determine ovule number in Arabidopsis.

Seeds derive from ovules upon fertilization and therefore the total number of ovules determines the final seed yield, a fundamental trait in crop plants. Among the factors that co-ordinate the process of ovule formation, the transcription factors CUP-SHAPED COTYLEDON 1 (CUC1) and CUC2 and the hormone cytokinin (CK) have a particularly prominent role. Indeed, the absence of both CUC1 and CUC2 causes a severe reduction in ovule number, a phenotype that can be rescued by CK treatment. In this study, we combined CK quantification with an integrative genome-wide target identification approach to select Arabidopsis genes regulated by CUCs that are also involved in CK metabolism. We focused our attention on the functional characterization of UDP-GLUCOSYL TRANSFERASE 85A3 (UGT85A3) and UGT73C1, which are up-regulated in the absence of CUC1 and CUC2 and encode enzymes able to catalyse CK inactivation by O-glucosylation. Our results demonstrate a role for these UGTs as a link between CUCs and CK homeostasis, and highlight the importance of CUCs and CKs in the determination of seed yield.

Transcriptomic Signature of the SHATTERPROOF2 Expression Domain Reveals the Meristematic Nature of Arabidopsis Gynoecial Medial Domain.

Plant meristems, like animal stem cell niches, maintain a pool of multipotent, undifferentiated cells that divide and differentiate to give rise to organs. In Arabidopsis (Arabidopsis thaliana), the carpel margin meristem is a vital meristematic structure that generates ovules from the medial domain of the gynoecium, the female floral reproductive structure. The molecular mechanisms that specify this meristematic region and regulate its organogenic potential are poorly understood. Here, we present a novel approach to analyze the transcriptional signature of the medial domain of the Arabidopsis gynoecium, highlighting the developmental stages that immediately proceed ovule initiation, the earliest stages of seed development. Using a floral synchronization system and a SHATTERPROOF2 (SHP2) domain-specific reporter, paired with FACS and RNA sequencing, we assayed the transcriptome of the gynoecial medial domain with temporal and spatial precision. This analysis reveals a set of genes that are differentially expressed within the SHP2 expression domain, including genes that have been shown previously to function during the development of medial domain-derived structures, including the ovules, thus validating our approach. Global analyses of the transcriptomic data set indicate a similarity of the pSHP2-expressing cell population to previously characterized meristematic domains, further supporting the meristematic nature of this gynoecial tissue. Our method identifies additional genes including novel isoforms, cis-natural antisense transcripts, and a previously unrecognized member of the REPRODUCTIVE MERISTEM family of transcriptional regulators that are potential novel regulators of medial domain development. This data set provides genome-wide transcriptional insight into the development of the carpel margin meristem in Arabidopsis.

Activities Performed by ASCO-Sponsored Oncology Student Interest Groups in Latin America: Assessing Members' Preferences and Leaders' Challenges.

PURPOSE: In response to the worldwide shortage of oncologists, ASCO established Oncology Student Interest Groups (OSIGs) to increase oncology exposure at medical schools. However, there is limited guidance on the activities they should undergo. The main purposes of this study were (1) to assess the preferences and perceptions of OSIG members about their group events and (2) to describe the difficulties faced by leaders to carry out OSIGs' tasks. METHODS: In this multicenter, cross-sectional study, group members and leaders from five active Latin American OSIGs were invited to answer anonymous web-based surveys exploring members' attitudes toward group activities and leaders' challenges when carrying them out. Data collection was conducted from March to June 2021. RESULTS: Responses from 142 medical students and four OSIGs leaders were analyzed. In total, 83% of student members considered that lectures with an oncology-related expert was very useful for increasing their overall interest in oncology. For increasing interest in cancer research, 87% deemed that participating in oncology research projects was very useful. Shadowing oncology professionals was very useful for at least 70% of members to increase their oncology knowledge and their interest in following an oncology-related career. Moreover, leaders' main challenges were having a high academic load, little response from members, lack of interesting ideas and protected time for OSIGs' events, and limited support from their school. CONCLUSION: OSIGs' leaders, medical schools, and international oncology organizations should work together to design activities that increase medical students' exposure to oncology-related professionals and encourage their participation in international oncological events. These schools and organizations should actively support OSIG leaders when facing difficulties to prevent members' disengagement and groups' discontinuation.

Alternative Splicing Generates a MONOPTEROS Isoform Required for Ovule Development.

The plant hormone auxin is a fundamental regulator of organ patterning and development that regulates gene expression via the canonical AUXIN RESPONSE FACTOR (ARF) and AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) combinatorial system. ARF and Aux/IAA factors interact, but at high auxin concentrations, the Aux/IAA transcriptional repressor is degraded, allowing ARF-containing complexes to activate gene expression. ARF5/MONOPTEROS (MP) is an important integrator of auxin signaling in Arabidopsis development and activates gene transcription in cells with elevated auxin levels. Here, we show that in ovules, MP is expressed in cells with low levels of auxin and can activate the expression of direct target genes. We identified and characterized a splice variant of MP that encodes a biologically functional isoform that lacks the Aux/IAA interaction domain. This MP11ir isoform was able to complement inflorescence, floral, and ovule developmental defects in mp mutants, suggesting that it was fully functional. Our findings describe a novel scenario in which ARF post-transcriptional regulation controls the formation of an isoform that can function as a transcriptional activator in regions of subthreshold auxin concentration.

[Wolff Parkinson white syndrome in a young infant]. / Síndrome de wolff parkinson white en un lactante menor.

Wolff Parkinson White Syndrome occurs due to the presence of accessory pathways that abnormally communicate the atria with the ventricles. It is one of the main causes of paroxysmal supraventricular tachycardia in young people and adolescents, in whom the ideal management is catheter ablation. This syndrome can also occur in younger patients such as neonates and infants, where the therapeutic options are different. We present the case of a 47-day-old patient who was admitted to a public pediatric hospital in Peru due to vomiting. Upon admission, she showed a heart rate of 250 beats per minute; wide QRS complex tachycardia was documented; later, on the electrocardiogram in sinus rhythm, signs of pre-excitation were evident.

Effectiveness of steroids versus placebo in preventing upper airway obstruction after extubation in critically ill children: rationale and design of a multicentric, double-blind, randomized study.

BACKGROUND: Post-extubation upper airway obstruction (UAO) is a frequent complication causing stridor and respiratory distress, which occasionally require reintubation, thereby increasing morbidity and mortality rates. Contradictory results have been obtained in studies assessing the effectiveness of steroids in preventing post-extubation UAO, and the available evidence is limited. We designed a multicentric randomized, placebo-controlled study to explore the effectiveness of dexamethasone in preventing post-extubation UAO in children. METHODS: A multicentric, prospective, double-blind, randomized, placebo-controlled, phase IV clinical trial has been designed. The sample will include pediatric patients who are between 1 month and 16 years of age and who have been intubated for more than 48 h. Patients who have airway disorders or who have received steroids within the previous seven days will be excluded. Patients will be randomly assigned to receive either placebo or a therapy with dexamethasone 0.25 mg/kg every 6 h to be started 6 to 12 h prior to extubation (to a total of four doses). Randomization will be performed at a 1:1 ratio. Follow-up of patients will be carried out for 48 h after extubation. The main objective of this study is to access the reduction in the incidence of moderate to severe UAO symptoms following extubation. Secondary objectives include assessing the decrease in the incidence of reintubation, evaluating the use of additional therapies for UAO, and monitoring potential side effects of dexamethasone. DISCUSSION: The results of this study will contribute to the existing evidence on prophylaxis for post-extubation airway obstruction. TRIAL REGISTRATION: EudraCT identifier: 2009-016596-30. Registered on May 11, 2010.

Production of cecropin A in transgenic rice plants has an impact on host gene expression.

Expression of the cecropin A gene in rice confers resistance to the rice blast fungus Magnaporthe oryzae. In this study, a polymerase chain reaction-based suppression subtractive hybridization approach was used to generate a cDNA macroarray from the elite japonica rice (Oryza sativa L.) cultivar 'Senia'. Gene expression studies revealed that the expression of components of the protein secretory and vesicular transport machinery is co-ordinately activated at the pre-invasive stage of infection of rice by the blast fungus. Comparisons of gene expression between wild-type and cecropin A plants revealed the over-expression of genes involved in protection against oxidative stress in transgenic plants in the absence of the pathogen, which correlated well with the tolerance of these plants to oxidative stress. A subcellular fractionation analysis suggested that cecropin A accumulates in the endoplasmic reticulum in cecropin A rice. Moreover, a large number of genes related to the processes of synthesis, folding and stabilization of proteins that enter into the secretory pathway are over-expressed in cecropin A rice, confirming that these plants constitutively express the unfolded protein response. Transgenic expression of cecropin A in rice has an effect on the transcriptional reprogramming that accompanies plant adaptation to fungal infection. Overall, this study provides evidence for transgene-induced changes in gene expression in cecropin A rice under both optimal growth conditions and stress conditions imposed by fungal infection. The data also indicate that resistance to blast in cecropin A rice may be the consequence of a combination of the antifungal activity of cecropin A and cecropin A-mediated over-expression of rice genes.

Tratamiento intervencionista de las cardiopatías congénitas con hiperflujo pulmonar / Interventional treatment of congenital heart defects with pulmonary hyperflow

Resumen Introducción: En los últimos años se han desarrollado diversos dispositivos oclusores que permiten evitar la cirugía cardíaca en los pacientes con cardiopatías congénitas con hiperflujo pulmonar. Objetivo: Describir la experiencia en el cierre percutáneo de las cardiopatías con hiperflujo. Método: Mediante un estudio descriptivo y retrospectivo se revisaron las historias clínicas de los pacientes sometidos a intervencionismo cardíaco de 2016 a 2020. Resultados: De 706 procedimientos realizados en el periodo, el 35% fueron terapéuticos. De ellos, 189 correspondieron a nuestra serie de pacientes intervenidos con diagnósticos de persistencia del conducto arterioso (PCA) (n = 164), comunicación interauricular (CIA) (n = 21) y comunicación interventricular (CIV) (n = 4). Los datos clínicos y demográficos fueron en PCA 3.4 años (0.7-15) y 10.2 kg (6.1-46), en CIA 7.2 años (6-15) y 17.5 kg (15-38), y en CIV 7.25 años (6-9) y 20.75 kg (16-27). Referente al tamaño de los defectos cardíacos, el promedio fue para PCA 4.3 mm, para CIA 19.1 mm y para CIV 6.75 mm. Los dispositivos más utilizados fueron Amplatzer PDA y ASD, y Occlutech PDA. La tasa de éxito fue adecuada: PCA 95%, CIA 90% y CIV 75%. Reportamos una baja incidencia de complicaciones y generalmente menores, como shunt residual y hemólisis. Conclusiones: El manejo intervencionista de las cardiopatías congénitas con hiperflujo pulmonar es cada vez más frecuente con la disponibilidad de oclusores en nuestro medio, así como por el desarrollo de nuevos centros y el mayor entrenamiento de cardiólogos intervencionistas, lo que ha permitido mejores tasas de éxito y menor índice de complicaciones.

Abstract Introduction: In recent years, various occlusive devices have been developed that make it possible to avoid cardiac surgery in patients with congenital heart disease with pulmonary hyperflow. Objective: To describe the experience in percutaneous closure in heart disease with hyperflow. Material and methods: Through a descriptive, retrospective study, the medical records of patients undergoing cardiac intervention were reviewed, from 2016 to 2020. Results: Of 706 procedures performed in this time, 35% corresponded to various therapeutic cases. Of these, 189 corresponded to our series of operated patients with diagnoses of PDA (n = 164), ASD (n = 21) and VSD (n = 4). The clinical and demographic data were: in PDA 3.4 years (0.7-15) and 10.2 kg (6.1-46), in ASD 7.2 years (6-15) and 17.5 kg (15-38), and in VSD 7.25 years (6-9) and 20.75 kg (16-27). Regarding the size of the heart defects, the average was 4.3 mm PDA, 19.1 mm ASD and 6.75 mm VSD. The most used occluding devices were Amplatzer PDA and ASD, and Occlutech PDA. The success rate was adequate, PDA 95%, ASD 90% and VSD 75%. We report a low incidence of complications and generally minor ones such as residual shunt and hemolysis. Conclusions: The interventional management of the congenital heart diseases with pulmonary hyperflow is increasingly frequent with the availability of occlusive as well as the development of new centers and more training of interventional cardiologists, which has allowed better success rates and lower complication rate.

SUMOylation Inhibition Mediated by Disruption of SUMO E1-E2 Interactions Confers Plant Susceptibility to Necrotrophic Fungal Pathogens.

Protein modification by SUMO modulates essential biological processes in eukaryotes. SUMOylation is facilitated by sequential action of the E1-activating, E2-conjugating, and E3-ligase enzymes. In plants, SUMO regulates plant development and stress responses, which are key determinants in agricultural productivity. To generate additional tools for advancing our knowledge about the SUMO biology, we have developed a strategy for inhibiting in vivo SUMO conjugation based on disruption of SUMO E1-E2 interactions through expression of E1 SAE2UFDCt domain. Targeted mutagenesis and phylogenetic analyses revealed that this inhibition involves a short motif in SAE2UFDCt highly divergent across kingdoms. Transgenic plants expressing the SAE2UFDCt domain displayed dose-dependent inhibition of SUMO conjugation, and have revealed the existence of a post-transcriptional mechanism that regulates SUMO E2 conjugating enzyme levels. Interestingly, these transgenic plants displayed increased susceptibility to necrotrophic fungal infections by Botrytis cinerea and Plectosphaerella cucumerina. Early after fungal inoculation, host SUMO conjugation was post-transcriptionally downregulated, suggesting that targeting SUMOylation machinery could constitute a novel mechanism for fungal pathogenicity. These findings support the role of SUMOylation as a mechanism involved in plant protection from environmental stresses. In addition, the strategy for inhibiting SUMO conjugation in vivo described in this study might be applicable in important crop plants and other non-plant organisms regardless of their genetic complexity.

Diversification of SUMO-activating enzyme in Arabidopsis: implications in SUMO conjugation.

Sumoylation is an essential posttranslational modification that participates in many biological processes including stress responses. However, little is known about the mechanisms that control Small Ubiquitin-like MOdifier (SUMO) conjugation in vivo. We have evaluated the regulatory role of the heterodimeric E1 activating enzyme, which catalyzes the first step in SUMO conjugation. We have established that the E1 large SAE2 and small SAE1 subunits are encoded by one and three genes, respectively, in the Arabidopsis genome. The three paralogs genes SAE1a, SAE1b1, and SAE1b2 are the result of two independent duplication events. Since SAE1b1 and SAE1b2 correspond to two identical copies, only two E1 small subunit isoforms are present in vivo: SAE1a and SAE1b. The E1 heterodimer nuclear localization is modulated by the C-terminal tail of the SAE2 subunit. In vitro, SUMO conjugation rate is dependent on the SAE1 isoform contained in the E1 holoenzyme and our results suggest that downstream steps to SUMO-E1 thioester bond formation are affected. In vivo, SAE1a isoform deletion in T-DNA insertion mutant plants conferred sumoylation defects upon abiotic stress, consistent with a sumoylation defective phenotype. Our results support previous data pointing to a regulatory role of the E1 activating enzyme during SUMO conjugation and provide a novel mechanism to control sumoylation in vivo by diversification of the E1 small subunit.

Resultados imediatos e de médio prazo da intervenção com stent ductal em recém-nascidos e lactentes / Immediate and medium-term outcomes of ductal stenting in neonates and infants

O implante de stents para manter o ducto arterial patente na cardiopatia congênita cianótica éuma alternativa à cirurgia de Blalock-Taussig modificada (BTm) em pacientes de alto risco. Descrevemos osresultados imediatos e de médio prazo do implante de stent em neonatos e lactentes com circulação pulmonarducto-dependente. Métodos: Trata-se de estudo descritivo e prospectivo, que incluiu diferentes cardiopatias congênitas cianóticas tratadas entre 2014 e 2015.Resultados: Avaliamos 14 pacientes, com média de idade de 46 dias e pesando 4,5 kg, sendo a atresia pulmonar associada à comunicação interventricular a cardiopatia mais tratada. A abordagem pela artéria femoral ocorreu em 70% dos procedimentos e, nos demais, por via carotídea. Stents de 3,5 × 12 mm foram usados na maioria dos casos, e o sucesso do implante foi obtido em 78% das intervenções (11/14). Os casos de insucesso foram encaminhados para cirurgia − uma delas em situação de urgência, que resultou em óbito. Ocorreu espasmo ductal < 48 horas em três pacientes que necessitaram de BTm, com evolução favorável. Complicações após a alta e nos primeiros 30 dias incluíram trombose de stent (2/11), uma delas controlada com redilatação e outra que evoluiu para óbito, e uma morte súbita (1/11). A mortalidade total foi de 21,4% (3/14). A patência do ducto arterial nos primeiros 6 meses foi obtida em 5 casos que foram submetidos à cirurgia paliativa.Conclusões: A experiência inicial de implante de stent ductal mostrou resultados imediatos favoráveis, e, emmédio prazo, mais de um terço dos pacientes com circulação pulmonar ducto-dependente manteve seus canaispatentes...

The implantation of stents to keep the ductus arteriosus patent in cyanotic congenital heart disease is an alternative to the modified Blalock-Taussig surgery (mBT) in high-risk patients. This study describes theimmediate and medium-term outcomes of stent implantation in neonates and infants with duct-dependentpulmonary circulation. Methods: This was a descriptive and prospective study including different cyanotic congenital heart diseases treated between 2014 and 2015. Results: Fourteen patients with a mean age of 46 days, and mean weight of 4.5 kg were assessed, andpulmonary artresia with interventricular communication was the most treated condition. The femoral artery approach was used in 70% of procedures; carotid approach was used in the remaining cases. Stents of 3.5 x 12 mm were used in most cases, and implant success was achieved in 78% of interventions (11/14). The failed cases were referred to surgery – one of them was an emergency, which resulted in death. Ductal spasm occurred in < 48 hours in three patients who required mBT, with favorable outcome. Complicationsafter discharge and within the first 30 days included stent thrombosis (2/11), one of which was controlled with redilation, another progressed to death, and one sudden death (1/11). The overall mortality was 21.4% (3/14). A patent ductus arteriosus in the first 6 months was present in five cases, which underwent palliative surgery.Conclusions: The initial experience of ductal stenting showed favorable immediate outcomes, but in the mediumterm, little more than a third of the cases maintained a patent ductus arteriosus within 6 months...

Ritmo circadiano e infarto de miocardio / Circadian rhytm and miocardial infarction

OBJETIVO: Determinar la variación circadiana del inicio del infarto de miocardio así como la población en riesgo en nuestro medio. DISEÑO: Se incluyeron los pacientes con infarto de miocardio admitidos a la Unidad de Cuidados Intensivos Coronario del Hospital Alberto Sabogal del IPSS, desde Enero de 1985 a febrero de 1991. Metodología retrospectiva desde enero 85 a febrero 90, y metodología prospectiva desde marzo 1990 a febrero 1991. RESULTADOS: De 103 pacientes estudiados, se determinó que el factor de riesgo más importante asociado fue Hipertensión arterial y Tabaquismo. Así mismo se determinó que entre las 00 y las 12 hs se presentaron el mayor número de infartos de miocardio. CONCLUSIONES: En nuestra serie estudiada, Hipertensión arterial y Tabaquismo constituyen los factores de riesgo más importante, y las horas de la mañana, es el momento en que se presenta con mayor frecuencia el mayor número de casos