Papers by Roberto Machado
Current Agricultural Science and Technology, 1996
Estudou-se o trabalho desenvolvido por escarificador em planossolo, operando tres hastes na profu... more Estudou-se o trabalho desenvolvido por escarificador em planossolo, operando tres hastes na profundidade media de 0,2m, quanto a esforco de tracao, area transversal de solo mobilizado, resistencia especifica operacional e potencia na barra de tracao, em dois niveis de teor de agua no solo (Ug1=7,2% e Ug2=12,0%) e tres velocidades de trabalho (V1=2,6km/h, V2=3,6km/h e V3=4,8km/h). Os resultados obtidos mostram que, tanto a velocidade de trabalho quanto o teor de agua no solo, dentro das faixas estudadas, nao influenciam significativamente o esforco de tracao, a area transversal de solo mobilizado e a resistencia especifica operacional. A potencia exigida na barra de tracao esta influenciada significativamente pela velocidade de trabalho, sendo que o teor de agua no solo nao influenciou a mesma. O menor valor para resistencia especifica operacional (Reo=141,08kN/m2) foi obtido na condicao de velocidade igual a 4,8km/h e teor de agua no solo de 7,2%.
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American Journal of Hematology, 2021
The six‐minute walk test (6MWT) has been used in patients with sickle cell disease (SCD), in conj... more The six‐minute walk test (6MWT) has been used in patients with sickle cell disease (SCD), in conjunction with tricuspid regurgitant velocity (TRV) and plasma N‐terminal pro‐brain natriuretic peptide (NT‐pro BNP), to assess risk of having pulmonary hypertension. Exercise‐induced vital sign changes (VSCs) are predictors of clinical outcomes in other diseases. In this study, we assess the predictors and prognostic value of 6MWT VSC in adult SCD patients. Data from a multinational study of SCD patients (Treatment of Pulmonary Hypertension with Sildenafil: walk‐PHaSST) were used to calculate the 6MWT VSC. Predictors of VSC were identified by a multivariable analysis, and a survival analysis was conducted by the Cox proportional hazard method. An increase in heart rate was observed in 90% of the 630 SCD adults, 77% of patients had an increase in systolic blood pressure (SBP), and 50% of patients had a decrease in oxygen saturation. TRV (odds ratio [OR] = 1.82, p = .020), absolute reticulocyte count (OR = 1.03, p < .001), and hemoglobin (OR = 0.99, p = .035) predicted oxygen desaturation ≥ 3% during the 6MWT. In the adjusted analysis, SBP increase during the 6MWT was associated with improved survival (hazards ratio = 0.3, 95% confidence interval: 0.1–0.8). Increases in heart rate and blood pressure, as well as oxygen desaturation, are common in adults with SCD during the 6MWT. VSC is associated with markers of anemia and TRV and can be used for risk stratification. Any increase in SBP during the 6MWT was associated with improved survival and may be indicative of a patient's ability to increase stroke volume.
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Journal of the Neurological Sciences, 2021
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BackgroundDelirium incidence, duration and severity in patients admitted to the intensive care un... more BackgroundDelirium incidence, duration and severity in patients admitted to the intensive care unit (ICU) due to COVID-19 is not known.MethodsWe conducted an observational study at two large urban academic Level 1 trauma centers. Consecutive patients admitted to the ICU with a positive SARS-CoV-2 nasopharyngeal swab polymerase chain reaction test from March 1st, 2020 to April 27, 2020 were included. Individuals younger than 18 years of age, without any documented delirium assessments (CAM-ICU), or without a discharge disposition were excluded. The primary outcomes were delirium rates and delirium duration and the secondary outcome was delirium severity. Outcomes were assessed for up to the first 14 days of ICU stay.ResultsOf 243 consecutive patients with confirmed COVID-19 admitted to the ICU, 144 met eligibility criteria and were included in the analysis. Delirium occurred in 73.6% (106/144) and delirium or coma occurred in 76.4% (110/144). Sixty-three percent of patients were posi...
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Blood, 2004
We and others have published biochemical and physiological evidence supporting a model in which i... more We and others have published biochemical and physiological evidence supporting a model in which intravascular hemolysis and oxidant stress in patients with sickle cell disease (SCD) results in impaired nitric oxide (NO) bioavailability, with an associated reduction in NO-dependent blood flow. This reduced bioavailability is characterized by NO destruction and thus a resistance to both endogenous and exogenous (nitroprusside, nitroglycerin, NONOates) NO. A crucial regulator of endothelial cell homeostasis, NO regulates basal vasodilation, inhibits platelet aggregation, and tonically inhibits expression of cell adhesion molecules by endothelial cells, including vascular cell adhesion molecule (VCAM-1). Statins have been reported to both improve NO-dependent blood flow and reduce oxidant stress in patients with hypercholesterolemia and in normal subjects. We therefore investigated whether atorvastatin has similar effects in patients with SCD. Five patients have completed the study (tar...
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American Journal of Hematology, 2019
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Blood, 2007
Nitric oxide- and cyclic nucleotide-linked pathways have been proposed to regulate fetal hemoglob... more Nitric oxide- and cyclic nucleotide-linked pathways have been proposed to regulate fetal hemoglobin expression in sickle cell disease (SCD), and phosphodiesterase-5 (PDE5) inhibition and arginine supplementation can enhance these pathways. In an open-label gender-biased study (due to earlier concerns about sildenafil-induced priapism), we examined HbF and markers of disease activity in 12 patients with SCD (HbSS,) who had confirmed hematologic stability on hydroxyurea therapy and who had been treated with three months of thrice daily L-arginine supplementation (0.1–0.2 g/Kg, n=6, 4 male) or sildenafil (PDE5 inhibitor, 25–100 mg, n=6, all female). An additional 12 patients received study drug but did not have stable lead-in HbF levels; their data, where available, is included in analyses of amino acid levels, tricuspid regurgitant (TR) jet measurements, and 6-minute walk (6MW) distance. 25 mg of sildenafil increased cGMP by an average of 2 pM/ml at 2 hours (n=5). Statistics between g...
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Blood, 2012
2869 Chuvash polycythemia (CP) is characterized by homozygosity for the R200W mutation in the von... more 2869 Chuvash polycythemia (CP) is characterized by homozygosity for the R200W mutation in the von Hippel Lindau gene (VHL). This rare genetic disorder causes elevated levels of hypoxia inducible factor (HIF)-1 and HIF-2 that trigger constitutive hypoxia responses at normoxia. Hypoxia is a recognized cause of pulmonary hypertension. We recently reported that systolic pulmonary artery pressure (SPAP) estimated by echocardiography-determined tricuspid regurgitation velocity (TRV) was elevated in 120 CP patients compared to 31 Chuvash controls (P = 0.005), and that increasing age (P = 0.001), increasing systemic pulse pressure (P = 0.003) and lower serum ferritin concentration (P = 0.009) were independent predictors of higher estimated SPAP in CP patients [Sable et al., 2012]. In this study, we profiled gene expression for 16,642 genes in peripheral blood mononuclear cells (PBMCs) derived from a cohort of 43 CP patients, and measured the TRV for these individuals. Based on a prospective...
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Revista de la CEPAL, 2005
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American Journal of Respiratory and Critical Care Medicine, 2018
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American journal of physiology. Lung cellular and molecular physiology, Mar 22, 2017
Sphingosine Kinase 1 (SphK1) upregulation is associated with pathologic pulmonary vascular remode... more Sphingosine Kinase 1 (SphK1) upregulation is associated with pathologic pulmonary vascular remodeling in pulmonary arterial hypertension (PAH), but the mechanisms controlling its expression are undefined. In this study, we sought to characterize the regulation of SphK1 expression by microRNAs (miRs). In silico analysis of the SphK1-3'UTR identified several putative miR binding sites, with miR-1-3p (miR-1) being the most highly predicted target. Therefore, we further investigated the role of miR-1 in modulating SPhK1 expression and characterized its effects on the phenotype of pulmonary artery smooth muscle cells (PASMCs) and the development of experimental pulmonary hypertension in vivo. Our results demonstrate that miR-1 is downregulated by hypoxia in PASMCs and can directly inhibit SphK1 expression. Overexpression of miR-1 in human PASMCs inhibits basal and hypoxia-induced proliferation and migration. Human PASMCs isolated from PAH patients exhibit reduced miR-1 expression. We...
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Chest, Jan 31, 2017
Pre-clinical studies have demonstrated that low-dose carbon monoxide (CO) can abrogate experiment... more Pre-clinical studies have demonstrated that low-dose carbon monoxide (CO) can abrogate experimental lung fibrosis. To test the therapeutic role of inhaled CO, we designed a clinical study in patients with idiopathic pulmonary fibrosis (IPF). We conducted a multicenter, phase IIa, double-blinded, sham-controlled, clinical trial. IPF patients were randomized to treatment with inhaled CO at 100 - 200 parts per million (ppm) or to inhaled 21% oxygen for 2 hours daily, twice weekly, for 12 weeks. The primary study endpoint was the difference in change in metalloproteinase-7 (MMP7) serum concentration following 12 weeks of treatment. Secondary endpoints included pulmonary function test measures, six-minute walk distance, rates of adverse events, acute exacerbation, hospitalization and death and quality of life measures. Fifty-eight subjects were randomized to treatment with inhaled CO (n = 29) or placebo (n = 29). Despite modest increases in CO blood levels, the change in MMP7 concentrati...
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Sarcoidosis, vasculitis, and diffuse lung diseases : official journal of WASOG, Jan 23, 2016
Pulmonary hypertension (PH) is a feared complication in patients with sarcoidosis.It is an import... more Pulmonary hypertension (PH) is a feared complication in patients with sarcoidosis.It is an important negative prognostic factor which is reflected as a priority given to these subjects for orthotopic lung transplantation. We evaluated the relationship between BNP, 6MWD test, DLCO% values and the severity of sarcoidosis-associated pulmonary hypertension. A retrospective chart review was conducted between January 2010 and January 2015 on consecutive confirmed adult subjects diagnosed with sarcoidosis. Demographics, medical comorbidities, clinical features, pulmonary function tests (PFTs), 6MWD test, transthoracic echocardiography, laboratory investigations, radiographic findings, treatment and outcome data were collected from medical records. Subjects with suspicion for PH (i.e. those with PASP ≥ 25 mmHg) were included in the study. PH severity was classified using PASP into mild (PASP 25-49 mmHg), moderate (50-69 mmHg) and severe (≥70 mmHg). We evaluated the strength of correlation b...
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Revista Brasileira de Oftalmologia, 2016
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Sarcoidosis, vasculitis, and diffuse lung diseases : official journal of WASOG / World Association of Sarcoidosis and Other Granulomatous Disorders, Jan 29, 2016
There is no known marker to screen patients with sarcoidosis to determine the risk of progression... more There is no known marker to screen patients with sarcoidosis to determine the risk of progression to pulmonary fibrosis. We aimed to identify potential noninvasive biomarkers for early detection of pulmonary fibrosing sarcoidosis. A case-control study was performed on African Americans with confirmed sarcoidosis included 31 subjects with pulmonary fibrosis vs. 36 without pulmonary fibrosis. Plasma samples were analyzed by liquid chromatography-mass spectrum. Multivariate statistical analysis models were developed in a training set based on 50 age- and sex-matched samples to identify metabolites involved in the discrimination. Principal component analysis and orthogonal partial least squares-discriminant (OPLS) analysis coupled to the most influential variables were used to derive significant metabolic discriminations. Of the datasets from 171 feature peaks, 14 features including p-coumaroylagmatine and palmitoylcarnitine showed significant differences between fibrosing and non-fibr...
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Hospital Practice, 1998
The clinical stereotype that divides diabetic patients into those who are thin and need insulin a... more The clinical stereotype that divides diabetic patients into those who are thin and need insulin and those who are obese and do not need insulin can be misleading. Some patients with type 2 diabetes present with ketoacidosis and require insulin treatment. Many of them can be weaned from insulin, although they may require hypoglycemic therapy.
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Blood, Jan 12, 2016
Pulmonary hypertension (PH) affects approximately 10% of adult patients with sickle cell disease ... more Pulmonary hypertension (PH) affects approximately 10% of adult patients with sickle cell disease (SCD), particularly those with the homozygous genotype. An increase in pulmonary artery systolic pressure, estimated noninvasively by echocardiography, helps identify SCD patients at risk for PH but definitive diagnosis requires right heart catheterization. About half of SCD-related PH patients have pre-capillary PH with potential etiologies of 1) an NO deficiency state and vasculopathy consequent to intravascular hemolysis, 2) chronic pulmonary thromboembolism, or 3) upregulated hypoxic responses secondary to anemia, low O2 saturation and microvascular obstruction. The remainder have post-capillary PH secondary to left ventricular dysfunction. Though the pulmonary artery pressure in SCD patients with PH is only moderately elevated, they have a markedly higher risk of death than patients without PH. Guidelines for diagnosis and management of SCD-related PH were published recently by the ...
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Growing teratoma syndrome consists of germ cell tumors that grow following chemotherapy despite c... more Growing teratoma syndrome consists of germ cell tumors that grow following chemotherapy despite complete eradication of the malignant cells and normalization of the tumor markers. They can metastasize to any site, particularly the retroperitoneum, mediastinum and cervical region. Here we report our experience with this rare syndrome and stress the need for early recognition and treatment to avoid the subsequent morbidity and mortality associated with it. We reviewed the hospital records of patients suffering from testicular tumors with retroperitoneal metastasis treated at our hospital between January 2002 and December 2006. We included those who underwent radical orchiectomy, followed by chemotherapy and retroperitoneal lymphadenectomy for persistence of post-treatment large tumor, but whose tumor markers had normalized. In this period, fourteen patients underwent retroperitoneal lymphadenectomy for persistence of tumor masses and normalization of tumor markers. Of these, the resul...
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Nuclear Medicine and Molecular Imaging, 2015
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Papers by Roberto Machado