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INTRODUCTION: This study analyzed the impact of patients' age, sex, vaccination, immunosuppressive treatment, and previous comorbidities on the risk of developing persistent COVID-19 or SARS-CoV-2 virus reinfection. METHOD: Population-based observational retrospective study of a cohort of 110,726 patients aged 12 years or older, who were diagnosed with COVID-19 between June 1st, 2021 and February 28th, 2022 in the island of Gran Canaria. RESULTS: 340 patients suffered reinfection. The combination of advanced age, female sex and lack of complete or incomplete vaccination against COVID-19 was strongly predictive of reinfection (p<0.05). In the 188 patients who developed persistent COVID-19, the persistence of symptoms was more frequent in adult patients, women, and patients with a diagnosis of asthma. Complete vaccination was associated with a lower risk of reinfection ([OR] 0.05, 95%CI 0.04-0.07; p<0.05) and of developing persistent COVID-19 ([OR] 0.07, 95%CI 0.05-0.10; p<0.05). None of the patients with reinfection or persistent COVID-19 died during the period of the study. CONCLUSIONS: This study confirmed the link between age, sex, asthma and risk of persistent COVID-19. It was not possible to define the patient's comorbidities as a factor that influences the development of reinfection, but its association with age, sex, type of vaccine and hypertension was demonstrated. Higher vaccination coverage was associated with a lower risk of persistent COVID-19 or SARS-CoV-2 reinfection.
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Asma , COVID-19 , Adulto , Humanos , Feminino , SARS-CoV-2 , COVID-19/epidemiologia , Espanha/epidemiologia , Reinfecção , Estudos Retrospectivos , Asma/epidemiologiaRESUMO
OBJECTIVE: To analyze the frequency of influenza and SARS-CoV-2 co-infections, as well as the differences in the course of disease (risk of mortality, hospital and intensive care admissions) in patients infected with the SARS-CoV-2 virus in relation to flu vaccination status in the 2021-2022 season. METHODS: Population-based observational retrospective study in a cohort of 19,850 patients diagnosed with COVID-19 between June 1, 2021 and February 28, 2022 on the island of Gran Canaria. RESULTS: A total of 1,789 patients (9%) diagnosed with COVID-19 had received flu vaccinations. 13,676 people (68.9%) had a full course of COVID-19 vaccinations. In the period between June 1, 2021 and February 28, 2022, 8 cases of flu and COVID-19 coinfection were recorded. Hypertension (18.5%), asthma (12.8%) and diabetes (7.2%) were the most frequent comorbidities. There were 147 deaths (0.7%). Older patients ([OR] 1.11 95% CI 1.09-1.13) and people with cancer ([OR] 4.21 95% CI 2.58-6.89) had a higher risk of dying from COVID-19 (p<0.05). Female sex was noted as a protective factor ([OR] 0.61 95% CI 0.40-0.92). CONCLUSIONS: Old age, male sex and cancer were independent prognostic factors for mortality. Three doses of SARS-CoV-2 vaccines and influenza vaccines were highly effective in preventing COVID-19-related deaths and hospital admissions. These findings suggest that flu vaccination can help control the pandemic.
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COVID-19 , Coinfecção , Vacinas contra Influenza , Influenza Humana , Feminino , Humanos , Masculino , Vacinas contra COVID-19 , Progressão da Doença , Influenza Humana/prevenção & controle , Estudos Retrospectivos , SARS-CoV-2 , Espanha , VacinaçãoRESUMO
The effect of the ZrO2 content on the performance (activity, selectivity, stability) of In2O3-ZrO2 catalyst has been studied on the hydrogenation of CO2/CO mixtures. This effect is a key feature for the viability of using In2O3-ZrO2/SAPO-34 tandem catalysts for the direct conversion of CO2 and syngas into olefins via oxygenates as intermediates. The interest of co-feeding syngas together with CO2 resides in jointly valorizing syngas derived from biomass or wastes (via gasification) and supplying the required H2. The experiments of methanol synthesis and direct synthesis of olefins, with In2O3-ZrO2 and In2O3-ZrO2/SAPO-34 catalysts, respectively, have been carried out under the appropriate conditions for the direct olefins synthesis (400 °C, 30 bar, H2/COX ratio = 3) in an isothermal fixed bed reactor at low space time values (kinetic conditions) to evaluate the behavior and deactivation of the catalysts. The Zr/In ratio of 1/2 favors the conversion of CO2 and COX, attaining good oxygenates selectivity, and prevents the sintering attributable to the over-reduction of the In2O3 (more significant for syngas feeds). The improvement is more remarkable in the direct olefins synthesis, where the thermodynamic equilibrium of methanol formation is displaced, and methanation suppressed (in a greater extent for feeds with high CO content). With the In2O3-ZrO2/SAPO-34 tandem catalysts, the conversion of COx almost 5 folds respect oxygenates synthesis with In2O3-ZrO2 catalyst, meaning the yield of the target products boosts from â¼0.5% of oxygenates to >3% of olefins (selectivity >70%) for mixtures of CO2/COX of 0.5, where an optimum performance has been obtained.
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Alcenos , Dióxido de Carbono , Biomassa , Catálise , MetanolAssuntos
Lasers de Gás , Líquen Escleroso e Atrófico , Doenças da Vulva , Feminino , Humanos , Lasers de Gás/uso terapêutico , LuzRESUMO
PURPOSE: To assess the feasibility of performing same-day vascular flow redistribution and Yttrium-90 radioembolization (90Y-RE) for hepatic malignancies. MATERIALS AND METHODS: From November 2015 to February 2019, patients undergoing same-day hepatic flow redistribution during work-up angiography, 99mTechnetium-labeled macroaggregated albumin (99mTc-MAA) SPECT/CT and 90Y microsphere-RE, were recruited. Within 18 h following the delivery of 90Y resin microspheres, an 90Y-PET/CT study was performed. According to patients' vascular anatomy, flow redistribution was performed by microcoil embolization of extrahepatic branches (group A), intrahepatic non-tumoral vessels (group B) and intrahepatic tumoral arteries (group C). The accumulation of 99mTc-MAA particles and microspheres in the redistributed areas was qualitatively evaluated using a 5-point visual scale (grade 1 = < 25% accumulation; grade 5 = 100% accumulation). Differences in the distribution of microspheres among groups were assessed with Mann-Whitney U test. RESULTS: Twenty-two patients were treated for primary (n = 17) and secondary (n = 5) hepatic malignancies. The MAA-SPECT/CT showed uptake in all the redistributed areas. Regarding the accumulation of microspheres within the redistributed segments in all the groups, perfusion patterns were classified as 2 in 1 case, 4 in 6 cases and 5 in 15 cases. No statistically significant differences were observed between groups A and B-C (U value = 34, p = 0.32) and between groups B and C (U value = 26, p = 0.7). Mean predicted absorbed doses by the tumoral and normal hepatic tissues were 163.5 ± 131.2 Gy and 60.4 ± 69.3 Gy, respectively. Mean total procedure time (from work-up angiography to 90Y delivery) was 401 ± 0.055 min. CONCLUSION: Performing same-day redistribution of the arterial hepatic flow to the target and 90Y-microsphere delivery is feasible in the treatment of liver tumors. Clinical Trials Registry NCT03380130.
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Angiografia , Embolização Terapêutica/métodos , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/radioterapia , Fígado/irrigação sanguínea , Agregado de Albumina Marcado com Tecnécio Tc 99m/uso terapêutico , Radioisótopos de Ítrio/uso terapêutico , Adulto , Idoso , Albuminas , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluxo Sanguíneo Regional/fisiologia , Tomografia Computadorizada de Emissão de Fóton Único/métodosRESUMO
By GWAS studies on celiac disease, gene expression was studied at the level of the whole intestinal mucosa, composed by two different compartments: epithelium and lamina propria. Our aim is to analyse the gene-expression and DNA methylation of candidate genes in each of these compartments. Epithelium was separated from lamina propria in biopsies of CeD patients and CTRs using magnetic beads. Gene-expression was analysed by RT-PC; methylation analysis required bisulfite conversion and NGS. Reverse modulation of gene-expression and methylation in the same cellular compartment was observed for the IL21 and SH2B3 genes in CeD patients relative to CTRs. Bioinformatics analysis highlighted the regulatory elements in the genomic region of SH2B3 that altered methylation levels. The cREL and TNFAIP3 genes showed methylation patterns that were significantly different between CeD patients and CTRs. In CeD, the genes linked to inflammatory processes are up-regulated, whereas the genes involved in the cell adhesion/integrity of the intestinal barrier are down-regulated. These findings suggest a correlation between gene-expression and methylation profile for the IL21 and SH2B3 genes. We identified a "gene-expression phenotype" of CeD and showed that the abnormal response to dietary antigens in CeD might be related not to abnormalities of gene structure but to the regulation of molecular pathways.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Doença Celíaca/patologia , Metilação de DNA , Epigenômica/métodos , Perfilação da Expressão Gênica/métodos , Interleucinas/genética , Adolescente , Biópsia , Doença Celíaca/genética , Criança , Pré-Escolar , Duodeno/química , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Mucosa Intestinal/química , Masculino , Proteínas Proto-Oncogênicas c-ret/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genéticaRESUMO
OBJECTIVE: Interventional oncology (IO) is an emergent field in interventional radiology that can be considered the fourth pillar of oncology. Interventional oncology has the unique capability to treat malignancy in a loco-regional fashion enabling curative (percutaneous ablation), disease stabilization (intra-arterial chemo/radioembolization), and palliative treatment (such as biliary drainage or nephrostomy). The whole arsenal of IO acts by inducing necrosis and apoptosis, with interactions with the tumour's microenvironment potentially crucial for oncological outcomes. Considering that tumour's microenvironment is a pivotal target for both immuno-oncology and interventional-oncology, the interactions between these two anti-tumour weapons must be investigated to understand their synergy. Interestingly, substantial efforts have been directed to understand which technique combinations are best for specific tumours. This review article summarizes the latest scientific evidence highlighting the future prospective of this winning combination, integrating evidence-reported literature and experience-based perceptions.
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Técnicas de Ablação/métodos , Antineoplásicos Imunológicos/administração & dosagem , Oncologia/métodos , Neoplasias/terapia , Radiologia Intervencionista/métodos , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/imunologia , Ensaios Clínicos como Assunto , Humanos , Oncologia/tendências , Neoplasias/imunologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Intervalo Livre de Progressão , Radiologia Intervencionista/tendências , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia , Microambiente Tumoral/efeitos da radiaçãoRESUMO
Percutaneous liver ablation has become a cornerstone of the recently developed subspecialty of radiology - that is, interventional oncology. Thermal ablation technology has evolved rapidly during the past decades, with substantial technical and procedural improvements that can help obtain better clinical outcomes and safety profiles. Due to the widespread use of percutaneous ablation, a comprehensive review of the methodologic and technical considerations seems to be mandatory. This article summarizes the expert discussion and report from Mediterranean Interventional Oncology Live Congress (MIOLive 2017) that was held in Rome, Italy, integrating evidence-reported literature and experience-based perceptions, to assist not only residents and fellows who are training in interventional radiology but also practicing colleagues who are approaching to this locoregional treatment.
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Técnicas de Ablação/métodos , Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Humanos , Radiologia IntervencionistaRESUMO
Sorafenib is a multi-kinase inhibitor and a vascular endothelial growth factor (VEGF) inhibitor approved to treat patients with advanced hepatocellular carcinoma, renal cell carcinoma and differentiated thyroid carcinoma. Its most common side effects are asthenia/fatigue, skin toxicity, diarrhea and arterial hypertension. Reported respiratory adverse reactions include dyspnea, cough, pleural effusion and hoarseness. The aim of this report is to describe for the first time the occurrence of pneumatocele in two patients treated with Sorafenib. Patients had no respiratory symptoms and alternative diagnoses were ruled out. Primary tumors were different (liver metastases from a pancreatic neuroendocrine tumor and hepatocellular carcinoma) but both patients had been treated with yttrium 90 radioembolization 9 and 17 months before starting on Sorafenib, respectively. No complications occurred and Sorafenib withdrawal was followed by radiologic improvement.
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Transarterial therapies in the setting of primary and secondary liver malignancies are becoming an essential part of the oncology landscape. The mechanism of action of c-TACE is the induction of tumor necrosis due to the high concentration of the chemotherapeutic that is delivered only locally and to the embolic effect that causes ischemia and increased dwell time of the chemotherapeutic in the tumor. Recently, DEB-TACE has emerged as a variation of c-TACE with the potential for the selective delivery of large amounts of drugs to the tumor for a prolonged period, thereby decreasing plasma levels of the chemotherapeutic agent and related systemic effects. There is an increasing consensus that compared with conventional lipiodol-based regimen, DEB-TACE offers standardized methodology, is more reproducible and is associated with improved response and significantly better safety profile. Using an easy to access point by point format, this manuscript summarizes the expert discussion from the Mediterranean Interventional Oncology Live Congress (MIOLive 2017) about the role of TACE in the treatment of liver tumors.
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Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica , Neoplasias Hepáticas/terapia , Carcinoma Hepatocelular/patologia , Quimioembolização Terapêutica/efeitos adversos , Congressos como Assunto , Óleo Etiodado/química , Humanos , Neoplasias Hepáticas/patologia , Recidiva Local de Neoplasia , Seleção de PacientesRESUMO
Percutaneous and endovascular techniques take an important role in the therapeutic management of patients with hepatocarcinoma. Different techniques of percutaneous ablation, especially indicated in tumors up to 2cm diameter offer, at least, similar results to surgical resection. Taking advantage of double hepatic vascularization and exclusive tumor nutrition by the artery, several endovascular techniques of treating the tumor have been developed. Intra-arterial administration of embolizing particles, alone or charged with drug (chemoembolization), will produce ischemia and consequent necrosis with excellent results in selected patients. Certain types of particles may exclusively be carriers of a therapeutic agent when they incorporate a radioisotope that facilitates the direct intratumoral selective irradiation (radioembolization). This technique has demonstrated its efficacy in lesions not susceptible to be treated with other methods and should be considered, together with ablation and chemoembolization, in the therapeutic algorithms of hepatocarcinoma.
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Técnicas de Ablação , Carcinoma Hepatocelular/terapia , Embolização Terapêutica , Neoplasias Hepáticas/terapia , Idoso , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Microsphere and particle technology represent the next-generation agents that have formed the basis of interventional oncology, an evolving subspecialty of interventional radiology. One of these platforms, yttrium-90 microspheres, is increasingly being used as a treatment modality for primary and secondary liver tumors. Due to the widespread use of radioembolization, a comprehensive review of the methodologic and technical considerations seems to be mandatory. This article summarizes the expert discussion and report from Mediterranean Interventional Oncology Live Congress (MIOLive 2017) that was held in Rome, Italy, integrating evidence-reported literature and experience-based perceptions, to assist not only residents and fellows who are training in interventional radiologists but also practicing colleagues who are approaching to this intra-arterial treatment.
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Embolização Terapêutica , Neoplasias Hepáticas/terapia , Meios de Contraste/química , Humanos , Itália , Fígado/anatomia & histologia , Fígado/diagnóstico por imagem , Fígado/patologia , Neoplasias Hepáticas/patologia , Microesferas , Radioisótopos de Ítrio/químicaRESUMO
BACKGROUND: Osteosarcoma paediatric patients are usually treated with intra-arterial chemotherapy (QTia) which is admi-nistered directly to the tumour. This procedure exposes patients to ionizing radiation. Paediatric patients are especially sensitive to this exposure. METHODS: The total amount of ionizing radiation received from QTia administration was quantified in a group of 16 osteo-sarcoma paediatric patients from the Clínica Universidad de Navarra. RESULTS: The median of the total radiation received per patient was 33.4 Gy·cm2 (IQR: 43.33 Gy·cm2), and the median number of procedures performed per subject was 10 (IQR: 6.5). CONCLUSIONS: The study highlights the importance of quantifying the radiation received by a group of children and adoles-cents affected by osteosarcoma during treatment with QTia. Long-term side effects of this radiation should be considered in pae-diatric patients. Currently, there are no previous studies that provide data of the amount of ionizing radiation received through this procedure.
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Neoplasias Ósseas/tratamento farmacológico , Osteossarcoma/tratamento farmacológico , Exposição à Radiação/estatística & dados numéricos , Radiação Ionizante , Radiografia Intervencionista , Adolescente , Angiografia , Artérias , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estudos RetrospectivosRESUMO
In a small percentage of patients, sound, touch and even nociceptive stimulation in the presence of a light anaesthetic depth does not cause an electroencephalogram wave pattern of cortical activation (α, ß waves) as would be expected, but leads to a slowed electroencephalogram pattern instead. We report the case of a patient who on emerging from anaesthesia showed very slowed brain activity on the electroencephalogram and reduced algorithmic value, that lasted approximately 5min coinciding with sound and tactile stimulation. After keeping her under observation for 24h during the postoperative period she did not present any brain disorder that could justify that event.
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Monitores de Consciência , Recuperação Demorada da Anestesia/fisiopatologia , Eletroencefalografia , Idoso , Nível de Alerta , Recuperação Demorada da Anestesia/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Hipóxia-Isquemia Encefálica/diagnóstico , Histerectomia , Estimulação Física , Neoplasias Uterinas/cirurgiaRESUMO
Tigecycline is a broad spectrum antimicrobial agent, structurally similar to minocycline and that shares some tetracycline-related side effects. A case report is presented on a 68-year-old female who received tigecycline for a sepsis of unknown origin and who, in the following 5days, developed abdominal pain and elevated pancreatic enzymes, which suggested acute pancreatitis. After ruling out other origins, and according to the Naranjo adverse drug reaction probability scale, tigecycline was the probable cause of the acute pancreatitis, a complication that has been reported 5 times in the database of the Spanish pharmacosurveillance system since 2009. Close monitoring of abdominal signs and symptoms is recommended during treatment with tigecycline, since adverse effects affecting the digestive system are the most prevalent ones when using this drug.
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Antibacterianos/efeitos adversos , Cuidados Críticos , Minociclina/análogos & derivados , Pancreatite/induzido quimicamente , Doença Aguda , Idoso , Antibacterianos/uso terapêutico , Substituição de Medicamentos , Evolução Fatal , Feminino , Humanos , Minociclina/efeitos adversos , Minociclina/uso terapêutico , Insuficiência de Múltiplos Órgãos/etiologia , Sepse/tratamento farmacológico , TigeciclinaRESUMO
OBJECTIVES: To analyze the safety and efficacy of percutaneous placement of coated self-expanding metallic stents (SEMS) in patients with biliary leaks. MATERIAL AND METHODS: This ethics committee at our center approved this study. We retrospectively reviewed all coated SEMS placed between October 2008 and September 2015. We analyzed patient-related factors such as the primary underlying disease, prior hepatic procedures, and clinical outcome. We evaluated the location, the number and type of leak (anastomotic or non-anastomotic), and the characteristics of the interventional procedure (number of stents deployed, location of the stents, technical success, and primary functionality). We recorded the complications registered. RESULTS: We studied 14 patients (11 men and 3 women). The mean follow-up period was 375.5 days (range 15-1920 days). Leaks were postsurgical in 12 patients. One patient developed an arteriobilioportal fistula. In another, the biliary leak occurred secondary to the rupture of the common bile duct after ERCP. A total of 23 coated SEMS were placed, including 21 Fluency® stents (Bard, Tempe, AZ, USA) and 2 Wallflex® stents (Boston Scientific, Galway, Republic of Ireland). The technical success of the procedure was considered total in 11 (78.6%) patients, partial in 2 (14.3%) patients, and null in 1 (7.2%) patient. The clinical outcome was good in 13 of the 14 patients. The mean period of primary functionality of the coated SEMS was 331 days (range 15-1920 days). No major complications were observed in 11 (78.6%) patients. CONCLUSIONS: Percutaneous placement of coated SEMS for the treatment of benign biliary leaks is safe and efficacious, with a high rate of technical and clinical success and a moderate rate of complications.
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Bile , Extravasamento de Materiais Terapêuticos e Diagnósticos/cirurgia , Stents Metálicos Autoexpansíveis , Idoso , Idoso de 80 Anos ou mais , Materiais Revestidos Biocompatíveis , Feminino , Humanos , Fígado , Masculino , Pessoa de Meia-Idade , Implantação de Prótese/métodos , Estudos RetrospectivosRESUMO
OBJECTIVE: To review the principal findings on computed tomography angiography for segmental arterial mediolysis, and to emphasize the points that help to differentiate it from other vasculopathies such as vasculitis. We also review the protocols for follow-up and the various treatment options. CONCLUSION: Segmental arterial mediolysis is a rare disease that is defined as a non-atherosclerotic, non-hereditary, and non-inflammatory vasculopathy characterized by lysis of the medial layer of the arterial wall. It should be suspected in middle-aged patients with aneurysms, dissections, or spontaneous ruptures of visceral arteries of unknown etiology who do not fulfill the clinical and laboratory criteria for vasculitis. The arteries of the abdominal organs are the most commonly affected, including the arteries of the celiac trunk and the superior and inferior mesenteric arteries. Radiologically, segmental arterial mediolysis can present as arterial dilation; single or multiple, saccular or fusiform aneurysms; stenoses; or dissections.
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Artérias , Angiografia por Tomografia Computadorizada , Túnica Média/diagnóstico por imagem , Doenças Vasculares/diagnóstico por imagem , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade , Túnica Média/patologia , Doenças Vasculares/patologiaRESUMO
OBJECTIVES: To evaluate the safety and patency of self-expanding stents to treat hepatic venous outflow obstruction after orthotopic liver transplantation. To evaluate differences in the response between patients with early obstruction and patients with late obstruction. MATERIAL AND METHODS: This is a retrospective analysis of 16 patients with hepatic venous outflow obstruction after liver transplantation treated with stents (1996-2011). Follow-up included venography/manometry, ultrasonography, CT, and laboratory tests. We did a descriptive statistical analysis of the survival of patients and stents, technical and clinical success of the procedure, recurrence of obstruction, and complications of the procedure. We also did an inferential statistical analysis of the differences between patients with early and late obstruction. RESULTS: The mean follow-up period was 3.34 years (21-5,331 days). The technical success rate was 93.7%, and the clinical success rate was 81.2%. The rate of complications was 25%. The survival rates were 87.5% for patients and 92.5% for stents. The rate of recurrence was 12.5%. The rate of primary patency was 0.96 (95% CI 0.91-1) at 3 months, 0.96 (95% CI 0.91-1) at 6 months, 0.87 (95% CI 0.73-1) at 12 months, and 0.87 (95% CI 0.73-1) at 60 months. There were no significant differences between patients with early and late obstruction, although there was a trend toward higher rates of primary patency in patients with early obstruction (P=.091). CONCLUSIONS: Treating hepatic venous outflow obstruction after orthotopic transplantation with self-expanding stents is effective, durable, and effective. There are no significant differences between patients with early obstruction and those with late obstruction.
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Veias Hepáticas , Transplante de Fígado , Complicações Pós-Operatórias/cirurgia , Stents Metálicos Autoexpansíveis , Adulto , Idoso , Constrição Patológica/cirurgia , Procedimentos Endovasculares , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
STUDY QUESTION: Why are female mice that lack a functional p27 protein infertile? SUMMARY ANSWER: The absence of a functional p27 leads to a dramatic increase in the number of multi-oocyte follicles (MOFs) in juvenile female mice; p27 would promote the individualization of follicles favoring the development of fertile eggs. WHAT IS KNOWN ALREADY: p27-/- female mice are infertile. p27 suppresses excessive follicular endowment and activation and promotes follicular atresia in mice. MATERIALS AND METHODS: Ovaries from wild type (WT) and p27Kip1 mutant mice aged 2, 4 and 12 weeks were subjected to immunohistochemistry/immunofluorescence. The slides with whole organs serially sectioned were scanned and examined by image analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Compared with WT, p27Kip1 mutant pre-pubertal mice had a greater number of oocytes, a greater number of growing follicles and a greater number of MOFs. These differences were statistically significant (P < 0.05), particularly in the case of MOFs (P > 0.001). The unusually large number of MOFs in juvenile p27-deficient mice is a novel observation. In WT mice p27 protein remains present in the oocyte nucleus but gradually decreases in the ooplasm during follicular growth, while granulosa cells show dynamic, follicle stage-related changes. LIMITATIONS, REASONS FOR CAUTION: These results have been obtained in mice and they cannot be directly extrapolated to humans. WIDER IMPLICATIONS OF THE FINDINGS: The dramatic increase in the numbers of MOFs in juvenile p27 mutants has not been previously reported. The number of MOFs declines sharply as the mice become sexually mature, pointing to their negative selection. These findings open a new approach to the study of sterility. STUDY FUNDING/COMPETING INTERESTS: This study has been funded by the Basque Government, Dept. of Health grant 2007111063 and Dept. of Industry (Saiotek) grant S-PC11UN008. Jairo Perez-Sanz was the recipient of a grant from Fundación Jesús de Gangoiti Barrera. The authors have no conflicts of interest to declare.