WILLIAM OMAR CONTRERAS LOPEZ

(Fonte: Lattes)
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  • article 5 Citação(ões) na Scopus
    Effects of sexed semen and interactive effects on commercial in vitro embryo production when oocytes are collected from cows of Bos indicus, and Bos taurus breeding and crossbred cows of these subspecies
    (2015) LOPEZ, William Omar Contreras; ALVIS-MIRANDA, Hernando Raphael; GAMARRA, Andres Felipe; RENDON, Bibiana; BORDA, Diego Armando Vega; ALBICKER, Ulrich; FONOFF, Erich Talamoni; MARTINEZ-DIAZ, Mario
    A large scale commercial in vitro embryo production and in vitro fertilization record is reported when there was use of oocytes from Bos taurus (BT), Bos indicus (BI), and Bos Taurus/indicus (BT/BI) crossbred subspecies fertilized with sexed (SS) and conventional (CS) semen. The aim of the study was to analyze the impacts of use SS in a commercial embryo production center in Colombia. Non-pregnant (n = 800), healthy, and estrous cycling BT, BI, and BI/BT crossbred cows were selected to be used as oocyte donors. Viable oocytes from 733 ovum pick up sessions in cows of the BT (4663) and BI (7305), BT/BI (3605) groups were matured and fertilized with frozen thawed semen from commercial sires. Of all cultured oocytes (n = 15,573), 52.3% of the embryos (n = 8607) underwent cleavage while 3062(19.7%) developed to the blastocyst stage. For cows of the BT, SS and CS groups, there were similar cleavage rates; however, use of SS decreased blastocyst formation (15.6% versus 18.9%). In the BI group, use of SS increased cleavage rates (59.1% versus 53%, respectively) although there was no effect on blastocyst rate development (22.9% versus 21.9). In the BI/BT groups, use of SS decreased cleavage (44.4% versus 57.1%, respectively) and blastocyst rate development compared with the CS group (15.3% versus 20.1%, respectively). Data from this study indicate embryos from cows of the BT purebred or BI/BT crossbred had less in vitro developmental capacity compared to embryos derived from oocytes of cows that were purebred BI in tropical-subtropical regions.
  • article 8 Citação(ões) na Scopus
    Microendoscopy-guided percutaneous cordotomy for intractable pain: case series of 24 patients
    (2016) FONOFF, Erich Talamoni; LOPEZ, William Omar Contreras; OLIVEIRA, Ywzhe Sifuentes Almeida de; TEIXEIRA, Manoel Jacobsen
    OBJECTIVE The aim of this study was to show that microendoscopic guidance using a double-channel technique could be safely applied during percutaneous cordotomy and provides clear real-time visualization of the spinal cord and surrounding structures during the entire procedure. METHODS Twenty-four adult patients with intractable cancer pain were treated by microendoscopic-guided percutaneous radiofrequency (RF) cordotomy using the double -channel technique under local anesthesia. A percutaneous lateral puncture was performed initially under fluoroscopy guidance to localize the target. When the subarachnoid space was reached by the guiding cannula, the endoscope was inserted for visualization of the spinal cord and surrounding structures. After target visualization, a second needle was inserted to guide the RF electrode. Cordotomy was performed by a standard RF method. RESULTS The microendoscopic double -channel approach provided real-time visualization of the target in 91% of the cases. The other 9% of procedures were performed by the single -channel technique. Significant analgesia was achieved in over 90% of the cases. Two patients had transient ataxia that lasted for a few weeks until total recovery. CONCLUSIONS The use of percutaneous microendoscopic cordotomy with the double-channel technique is useful for specific manipulations of the spinal cord. It provides real-time visualization of the RF probe, thereby adding a degree of safety to the procedure.
  • article 2 Citação(ões) na Scopus
    Aesthetically optimal deep brain stimulation technique in patients with alopecia
    (2015) FONOFF, Erich Talamoni; TEIXEIRA, Manoel Jacobsen; NASCIMENTO, Clarissa Nobrega Gambarra; LOPEZ, William Omar
  • article 4 Citação(ões) na Scopus
    Mystery Case: Brown-Sequard syndrome caused by idiopathic spinal cord herniation
    (2016) FONOFF, Erich Talamoni; LOPEZ, William Omar Contreras; TEIXEIRA, Manoel Jacobsen
    A 48-year-old man developed numbness in the left leg, which progressed gradually to paresis and urinary incontinence. Neurologic examination revealed a left Brown-Sequard syndrome with leg paresis, mild spasticity, reduced proprioception, and contralateral thermal and painful hypoesthesia below T6. MRI revealed a thoracic spinal cord herniation (SCH) (figure). Idiopathic SCH is relatively rare. Pathogenesis involves a dura mater defect (see video on the Neurology (R) Web site at Neurology.org); herniation develops over a progressive pressure gradient through the dural fissure.(2) Surgical reduction is typically performed if symptoms progress, but mild symptoms may be eligible for conservative treatment and monitoring. Surgical spinal reduction and dural repair usually reverses neurologic deficits.
  • article 6 Citação(ões) na Scopus
    Simultaneous bilateral stereotactic procedure for deep brain stimulation implants: a significant step for reducing operation time
    (2016) FONOFF, Erich Talamoni; AZEVEDO, Angelo; ANGELOS, Jairo Silva dos; MARTINEZ, Raquel Chacon Ruiz; NAVARRO, Jessie; REIS, Paul Rodrigo; SEPULVEDA, Miguel Ernesto San Martin; CURY, Rubens Gisbert; GHILARDI, Maria Gabriela dos Santos; TEIXEIRA, Manoel Jacobsen; LOPEZ, William Omar Contreras
    OBJECTIVE Currently, bilateral procedures involve 2 sequential implants in each of the hemispheres. The present report demonstrates the feasibility of simultaneous bilateral procedures during the implantation of deep brain stimulation (DBS) leads. METHODS Fifty-seven patients with movement disorders underwent bilateral DBS implantation in the same study period. The authors compared the time required for the surgical implantation of deep brain electrodes in 2 randomly assigned groups. One group of 28 patients underwent traditional sequential electrode implantation, and the other 29 patients underwent simultaneous bilateral implantation. Clinical outcomes of the patients with Parkinson's disease (PD) who had undergone DBS implantation of the subthalamic nucleus using either of the 2 techniques were compared. RESULTS Overall, a reduction of 38.51% in total operating time for the simultaneous bilateral group (136.4 +/- 20.93 minutes) as compared with that for the traditional consecutive approach (220.3 +/- 27.58 minutes) was observed. Regarding clinical outcomes in the PD patients who underwent subthalamic nucleus DBS implantation, comparing the preoperative off-medication condition with the off-medication/on-stimulation condition 1 year after the surgery in both procedure groups, there was a mean 47.8% +/- 9.5% improvement in the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) score in the simultaneous group, while the sequential group experienced 47.5% +/- 15.8% improvement (p = 0.96). Moreover, a marked reduction in the levodopa-equivalent dose from preoperatively to postoperatively was similar in these 2 groups. The simultaneous bilateral procedure presented major advantages over the traditional sequential approach, with a shorter total operating time. CONCLUSIONS A simultaneous stereotactic approach significantly reduces the operation time in bilateral DBS procedures, resulting in decreased microrecording time, contributing to the optimization of functional stereotactic procedures.
  • article 5 Citação(ões) na Scopus
    Intrathecal Morphine Therapy in the Management of Status Dystonicus in Neurodegeneration Brain Iron Accumulation Type 1
    (2014) LOPEZ, William Omar Contreras; SCHROEDER, Humberto Kluge; NEVILLE, Iuri Santana; TEIXEIRA, Manoel Jacobsen; BARBOSA, Danilo Costa; MONACO, Bernardo Assumpcao de; FONOFF, Erich Talamoni
    Neurodegeneration with brain iron accumulation type 1 (NBIA-1) is a rare disorder characterized by progressive extrapyramidal dysfunction and dementia. NBIA-1 encompasses typical iron brain accumulation, mostly in the globus pallidus with secondary dementia, spasticity, rigidity, dystonia, and choreoathetosis. Treatment remains mostly symptomatic and is challenging. We present the case of a 14-year-old boy diagnosed with NBIA-1, presenting intractable progressive generalized dystonia leading to unresponsive status dystonicus (SD). The patient received a SynchroMed II (model 8637) programmable system pump (Medtronic (R), Inc.) implant with an Ascenda intrathecal catheter for intrathecal morphine therapy (IMT). The initial dose of morphine was 1.0 mg/day. Overall, we observed no complications with IMT treatment and important improvement of the patient's motor function with stabilization of his incapacitating dystonia and his quality of life. On the Global Dystonia Severity Rating Scale, he presented 52% improvement, 30% improvement on the Unified Dystonia Rating Scale, and 38% improvement on the Fahn-Marsden Rating Scale after 10 months, when the dose was 1.7 mg/day. IMT should be considered as a potential palliative treatment in the management of intractable dystonia and SD secondary to NBIA-1. (C) 2015 S. Karger AG, Basel
  • article 44 Citação(ões) na Scopus
    Listenmee (R) and Listenmee (R) smartphone application: Synchronizing walking to rhythmic auditory cues to improve gait in Parkinson's disease
    (2014) LOPEZ, William Omar Contreras; HIGUERA, Carlos Andres Escalante; FONOFF, Erich Talamoni; SOUZA, Carolina de Oliveira; ALBICKER, Ulrich; MARTINEZ, Jairo Alberto Espinoza
    Evidence supports the use of rhythmic external auditory signals to improve gait in PD patients (Arias 82 Cudeiro, 2008; Kenyon & Thaut, 2000; McIntosh, Rice & Thaut, 1994; McIntosh et al., 1997; Morris, lansek, & Matyas, 1994; Thaut, McIntosh, 82 Rice, 1997; Suteerawattananon, Morris, Etnyre, Jankovic, & Protas, 2004; Willems, Nieuwboer, Chavert, & Desloovere, 2006). However, few prototypes are available for daily use, and to our knowledge, none utilize a smartphone application allowing individualized sounds and cadence. Therefore, we analyzed the effects on gait of Listenmee (R), an intelligent glasses system with a portable auditory device, and present its smartphone application, the Listenmee app (R), offering over 100 different sounds and an adjustable metronome to individualize the cueing rate as well as its smartwatch with accelerometer to detect magnitude and direction of the proper acceleration, track calorie count, sleep patterns, steps count and daily distances. The present study included patients with idiopathic PD presented gait disturbances including freezing. Auditory rhythmic cues were delivered through Listenmee (R). Performance was analyzed in a motion and gait analysis laboratory. The results revealed significant improvements in gait performance over three major dependent variables: walking speed in 38.1%, cadence in 28.1% and stride length in 44.5%. Our findings suggest that auditory cueing through Listenmee (R) may significantly enhance gait performance. Further studies are needed to elucidate the potential role and maximize the benefits of these portable devices.