Examinando por Autor "Silva Sieger, Federico Arturo"
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- PublicaciónAcceso abiertoAsociación entre niveles de proteína C-reactiva y oxido nítrico con el pronostico de pacientes con enfermedad cerebro vascular isquémica(2015-04) García, Ronald G.; Rosso, Pedro; García, Zaira M.; Álvarez Camacho, Julie; Suárez, Uriel; Gómez Arbeláez, Diego; Lopez-Jaramillo, Patricio; Silva Sieger, Federico ArturoIntroduction: Inflammation and alterations in the bioavailability of nitric oxide (NO) have been involved in the pathophysiology of cerebrovascular disease. Objective: The aim of the study was to determine the prognostic value of measuring NO metabolites and inflammatory markers in patients with acute ischemic stroke. Materials and methods: A total of 158 patients with acute ischemic stroke were included in an observational cohort study. Between 48 and 72 hours post admission, a fasting blood sample was taken to determine the biochemical profile, inflammatory markers (CRP, IL1-β, IL6, TNF-α) and nitrites/nitrates plasma levels. The cohort’s follow-up was conducted for two years to determine the occurrence of a new event (stroke, myocardial infarction, heart failure) or death of vascular origin. Comparisons between groups were made using the log-rank test. A Cox multivariate regression analysis permitted to determine factors independently associated with the outcome. Results: The mean age was 70.5 ± 12.8 years. 39.2% of the subjects presented the outcome during the first 24 months of follow-up. CRP levels > 12 mg/L (HR 2.22, 95% CI 1.07-4.59) and a score > 13 on the NIHSS scale at admission (HR 2.81 95% CI 1.46-5.41) were significantly associated with an increased risk of a new event. The combination of CRP levels < 12 mg/L and nitrites/nitrates levels < 35.5 mmol/L was identified as a protective factor (HR 0.21, 95% CI 0.06-0.71). Conclusion: This study demonstrates that the determination of CRP and NOx levels could be beneficial in clinical practice to stratify the risk of future events or death of vascular origin in acute ischemic stroke patients.
- PublicaciónRestringidoDouble blind, randomized controlled trial, to evaluate the effectiveness of a controlled nitric oxide releasing patch versus meglumine antimoniate in the treatment of cutaneous leishmaniasis [NCT00317629](2006-05-15) Silva, Sandra Y.; Rueda, Ligia C.; López Casillas, Marcos; Vélez, Iván D.; Rueda Clausen, Christian F.; Smith, Daniel J.; Muñoz, Gerardo; Mosquera, Hernando; Silva Sieger, Federico Arturo; Buitrago, Adriana; Díaz, Holger; Lopez-Jaramillo, PatricioBackground: Cutaneous Leishmaniasis is a worldwide disease, endemic in 88 countries, that has shown an increasing incidence over the last two decades. So far, pentavalent antimony compounds have been considered the treatment of choice, with a percentage of cure of about 85%. However, the high efficacy of these drugs is counteracted by their many disadvantages and adverse events. Previous studies have shown nitric oxide to be a potential alternative treatment when administered topically with no serious adverse events. However, due to the unstable nitric oxide release, the topical donors needed to be applied frequently, making the adherence to the treatment difficult. The electrospinning technique has allowed the production of a multilayer transdermal patch that produces a continuous and stable nitric oxide release. The main objective of this study is to evaluate this novel nitric oxide topical donor for the treatment of cutaneous leishmaniasis. Methods and design: A double-blind, randomized, double-masked, placebo-controlled clinical trial, including 620 patients from endemic areas for Leishmaniasis in Colombia was designed to investigate whether this patch is as effective as meglumine antimoniate for the treatment of cutaneous leishmaniasis but with less adverse events. Subjects with ulcers characteristic of cutaneous leishmaniasis will be medically evaluated and laboratory tests and parasitological confirmation performed. After checking the inclusion/exclusion criteria, the patients will be randomly assigned to one of two groups. During 20 days Group 1 will receive simultaneously meglumine antimoniate and placebo of nitric oxide patches while Group 2 will receive placebo of meglumine antimoniate and active nitric oxide patches. During the treatment visits, the medicationswill be daily administered and the presence of adverse events assessed. During the follow-up, the research group will visit the patients at days 21, 45, 90 and 180. The healing process of the ulcer, the health of the participants, recidivisms and/or reinfection will also be assessed. The evolution of the ulcers will be photographically registered. In case that the effectiveness of the patches is demonstrated, a novel and safe therapeutic alternative for one of the most important public health problems in many countries will be available to patients.
- PublicaciónRestringidoDouble blind, randomized, placebo controlled clinical trial for the treatment of diabetic foot ulcers, using a nitric oxide releasing patch : PATHON(2007-09-26) Silva, Sandra Y.; Rueda, Ligia C.; Márquez, Gustavo; López Casillas, Marcos; Smith, Daniel J.; Calderón, Carlos A.; Castillo, Juan C.; Matute, Jaime; Rueda Clausen, Christian F.; Orduz, Arturo; Silva Sieger, Federico Arturo; Kampeerapappun, Piyaporn; Bhide, Mahesh; Lopez-Jaramillo, PatricioBackground: Diabetes Mellitus constitutes one of the most important public health problems due to its high prevalence and enormous social and economic consequences. Diabetic foot ulcers are one of the chronic complications of diabetes mellitus and constitute the most important cause of non-traumatic amputation of inferior limbs. It is estimated that 15% of the diabetic population will develop an ulcer sometime in their lives. Although novel therapies have been proposed, there is no effective treatment for this pathology. Naturally produced nitric oxide participates in the wound healing process by stimulating the synthesis of collagen, triggering the release of chemotactic cytokines, increasing blood vessels permeability, promoting angiogenic activity, stimulating the release of epidermical growth factors, and by interfering with the bacterial mitochondrial respiratory chain. Topically administered nitric oxide has demonstrated to be effective and safe for the treatment of chronic ulcers secondary to cutaneous leishmaniasis. However, due to their unstable nitric oxide release, the topical donors needed to be applied frequently, diminishing the adherence to the treatment. This difficulty has led to the development of a multilayer polymeric transdermal patch produced by electrospinning technique that guarantees a constant nitric oxide release. The main objective of this study is to evaluate the effectiveness and safety of this novel nitric oxide releasing wound dressing for the treatment of diabetic foot ulcers. Methods and design: A double-blind, placebo-controlled clinical trial, including 100 diabetic patients was designed. At the time of enrollment, a complete medical evaluation and laboratory tests will be performed, and those patients who meet the inclusion criteria randomly assigned to one of two groups. Over the course of 90 days group 1 will receive active patches and group 2 placebo patches. The patients will be seen by the research group at least every two weeks until the healing of the ulcer or the end of the treatment. During each visit the healing process of the ulcer, the patient's health status and the presence of adverse events will be assessed. Should the effectiveness of the patches be demonstrated an alternative treatment would then be available to patients.
- PublicaciónAcceso abiertoFisiopatología y tratamiento del dolor de miembro fantasma(2013-12-12) Malavera Angarita, Mayra Alejandra; Carrillo Villa, Sandra; Gomezese Ribero, Omar Fernando; García, Ronald G.; Silva Sieger, Federico ArturoIntroduction: Phantom limb pain may be present in up to 80% of patients subjected to amputation because oftrauma or peripheral vascular disease. Severalfactors have been associated with its occurrence, including pre-amputation pain, the etiology, and the amputation level. Objective: To review the current status of the pathophysiological mechanisms, treatment options and their efficacy for the management of phantom limb pain. Method: Non-systematic review ofthe literature in PubMed and Cochrane, of articles describing the pathophysiology and treatment of phantom limb pain. Results and conclusions: The proposed pathophysiological mechanisms are still in research and include peripheral, central and psychologicalfactors. Treatment options are still limited, and less than 10% of patients report long-term improvement.
- PublicaciónAcceso abiertoFundamentos y aplicaciones clínicas de la estimulación magnética transcraneal en neuropsiquiatría(2014) Malavera Angarita, Mayra Alejandra; Silva Sieger, Federico Arturo; García, Ronald G.; Rueda, Ligia C.; Carrillo Villa, SandraTranscranial Magnetic Stimulation (TMS) is a non-invasive method for stimulation of brain that is based on the ability of a generated magnetic field to penetrate skull and brain meninges, inducing an electric current in the brain tissues that produces neuronal depolarization. TMS can be applied as single pulse of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Its mechanism of action is currently unknown. Repetitive TMS can modify the excitability of the cerebral cortex, and has been postulated as a diagnostic and therapeutic tool in the area of neuropsychiatry. The aim of this article is to review the knowledge of the TMS as regards its basic principles, pathophysiological mechanism, and its usefulness in clinical practice.
- PublicaciónAcceso abiertoIncreased plasma levels of total homocysteine but not asymmetric dimethylarginine in hispanic subjects with ischemic stroke frecvi(2012-03) Rueda Clausen, Christian F.; Córdoba Porras, A.; Bedoya, G.; Silva Sieger, Federico Arturo; Zarruk, Juan G.; Lopez-Jaramillo, Patricio; Villa, L.A.BACKGROUND AND PURPOSE:Despite sharing some metabolic and pathological mechanisms, the reported association between total homocysteine (tHcy), asymmetric dimethylarginine (ADMA) and stroke remains controversial, particularly in Hispanic populations from developing countries in which genetic, socioeconomic, and nutritional factors are different to those described in developed countries. Our objectives were to determine the relationships of these factors to stroke and to each other independent of other cardiovascular risk factors, and to explore potential sex differences. METHODS: This national (Colombia) multicenter case-control study included 238 cases and 238 controls to evaluate traditional and emerging risk factors for ischemic stroke including tHcy and ADMA plasma levels. RESULTS: The median plasma levels of tHcy were 8.48 μM for controls and 10.01 μM for cases (P<0.0001). Plasma levels of tHcy between 12 and 50μM were considered moderate hyperhomocysteinemia (HtHcy). There were no differences in plasma ADMA concentration between groups (P=0.40). Plasma levels of ADMA and creatinine were not correlated (P=0.47). After adjusting for confounding factors, the presence of HtHcy was strongly associated with stroke (OR 8.97; P<0.0001). The adjusted association between HtHcy and stroke in men (OR 9.98) was comparable to that in women (OR 8.98) (P=0.41). CONCLUSIONS: In this Hispanic population, with relatively normal renal function, plasma levels of tHcy but not ADMA were associated with stroke independent of other cardiovascular risk factors.
- PublicaciónRestringidoA randomized, double blind, cross-over, placebo-controlled clinical trial to assess the effects of Candesartan on the insulin sensitivity on non diabetic, non hypertense subjects with dysglyce mia and abdominal obesity. "ARAMIA"(2006-09-07) Lopez-Jaramillo, Patricio; Pradilla, Lina P.; Lahera, Vicente; Silva Sieger, Federico Arturo; Rueda Clausen, Christian F.; Márquez, GustavoBackground: The raising prevalence of type-2 diabetes mellitus and obesity has been recognized as a major problem for public health, affecting both developed and developing countries. Impaired fasting plasma glucose has been previously associated with endothelial dysfunction, higher levels of inflammatory markers and increased risk of developing insulin resistance and cardiovascular events. Besides life-style changes, the blockade of the renin-angiotensin system has been proposed as a useful alternative intervention to improve insulin resistance and decrease the number of new type-2 diabetes cases. The aim of this clinical trial is to study the effect of the treatment with Candesartan, an angiotensin II receptor antagonist, on the insulin resistance, the plasma levels of adipoquines, oxidative stress and prothrombotic markers, in a group of non diabetic, non hypertensive, dysglycemic and obese subjects. Methods and design: A randomized, double blind, cross-over, placebo-controlled, clinical trial was designed to assess the effects of Candesartan (up to 32 mg/day during 6 months) on the Homeostasis Model Assessment (HOMA) index, lipid profile, protrombotic state, oxidative stress and plasma levels of inflammatory markers. The participants will be recruited in the "Fundación Cardiovascular de Colombia". Subjects who fullfil selection criteria will receive permanent educational, nutritional and exercise support during their participation in the study. After a 15 days-run-in period with placebo and life-style recommendations, the patients who have a treatment compliance equal or greater than 80% will be randomlly assigned to one of the treatment groups. Group A will receive Candesartan during 6 months and placebo during 6 months. Group B will receive placebo during the first 6 months, and then, Candesartan during the last 6 months.Control visits will be programed monthly and all parameters of interest will be evaluated every 6 months. Hypothesis: Treatment with Candesartan, could improve the HOMA index, the response to the oral glucose tolerance test and reduce the plasma levels of adipoquines, oxidative stress and prothrombotic markers, in non diabetic, non hypertense subjects with dysglycemia and abdominal obesity, recruited from a population at high risk of developing insulin resistance. These effects are independent of the changes in arterial blood pressure. Trial registration: NCT00319202.
- PublicaciónAcceso abiertoRepetitive transcranial magnetic stimulation for phantom limb pain in land mine victims : A double-blinded, randomized, sham-controlled trial(2016-08) Malavera Angarita, Mayra Alejandra; Silva Sieger, Federico Arturo; Fregni, Felipe; Carrillo Villa, Sandra; García, Ronald G.We evaluated the effects of repetitive transcranial magnetic stimulation (rTMS) in the treatment of phantom limb pain (PLP) in land mine victims. Fifty-four patients with PLP were enrolled in a randomized, double-blinded, placebo-controlled, parallel group single-center trial. The intervention consisted of real or sham rTMS of M1 contralateral to the amputated leg. rTMS was given in series of 20 trains of 6-second duration (54-second intertrain, intensity 90% of motor threshold) at a stimulation rate of 10 Hz (1,200 pulses), 20 minutes per day, during 10 days. For the control group, a sham coil was used. The administration of active rTMS induced a significantly greater reduction in pain intensity (visual analogue scale scores) 15 days after treatment compared with sham stimulation (−53.38 ± 53.12% vs −22.93 ± 57.16%; mean between-group difference = 30.44%, 95% confidence interval, .30–60.58; P = .03). This effect was not significant 30 days after treatment. In addition, 19 subjects (70.3%) attained a clinically significant pain reduction (>30%) in the active group compared with 11 in the sham group (40.7%) 15 days after treatment (P = .03). The administration of 10 Hz rTMS on the contralateral primary motor cortex for 2 weeks in traumatic amputees with PLP induced significant clinical improvement in pain. Perspective High-frequency rTMS on the contralateral primary motor cortex of traumatic amputees induced a clinically significant pain reduction up to 15 days after treatment without any major secondary effect. These results indicate that rTMS is a safe and effective therapy in patients with PLP caused by land mine explosions.