Biomedical subjects

Eduardo Castillo

Publications and source records attributed to Eduardo Castillo.

4 recordsLinked to original sources

PubMed2006

An efficient method for the micropropagation of Agave species.

Despite their economic importance, the Agave spp. have not been genetically improved. This is probably owing to the fact that they have very long life cycles and many of them have an inefficient sexual reproduction mechanism. Micropropagation offers an alternative to this problem through the efficient cloning of selected high-yielding "elite" plants. We report here an efficient method to micropropagate agaves and a strategy for the management of large scale production that has been successfully applied to several Agave spp.

Agave↗

PubMed2005

Continent ileostomy: current experience.

PURPOSE: This study was designed to review our recent experience with continent ileostomies and evaluate patient outcomes. METHODS: Retrospective chart reviews and phone interviews of patients who underwent a continent ileostomy operation from 1993 to 2003 at the Ochsner Clinic Foundation were performed. RESULTS: Twenty-four patients (19 females; age range, 22-73 years) had construction of continent ileostomies (modified Kock pouch). There were no intraoperative mortalities or stoma-related deaths. The mean operating room time for primary construction was 3.9 +/- 0.57 hours with a mean length of stay of 7 +/- 2 days. The average follow-up period was 66 (range, 6-134) months. The most common underlying indication for the construction of a continent ileostomy was ulcerative colitis (71 percent). Thirteen patients had a continent ileostomy created for conversion of a Brooke ileostomy and seven for a failed ileoanal pouch. Other indications included colonic inertia and incontinence in three patients and one patient who had failed multiple operations for Hirschsprung's disease. A total of 28 revisions were performed in 14 patients (58 percent). Six patients required multiple procedures. Operative revisions included 12 skin level revision for stenosis, 11 operations for valve repairs, and 1 each for peristomal hernia repair, stomal relocation, and pouch repair for fistulas. Two patients had their pouches removed (Crohn's disease and inability to manage pouch). The need for revision by 12 months was 29 percent, and the average time period before the first revision was 24 months (range, 4 days to 109 months). The overall failure rate (converted to conventional ileostomy) was only 8.3 percent. Ninety percent of the patients have continent pouches and are satisfied with their pouch function. CONCLUSIONS: Continent ileostomies continue to have a high rate of reoperations, reasonable functional results, and are a viable option for failed ileal pouch-anal pouch patients. Surgeons electing to perform continent ileostomies must carefully select their patients and advise them of the high potential for reoperations. Despite a high reoperation rate, patients are pleased with their continent ileostomies.

Adult↗

PubMed2004

Magnetoencephalography (MEG) and magnetic source imaging (MSI).

BACKGROUND: Real-time, direct assessment of brain electrophysiology is critical for noninvasive functional mapping and for the identification of paroxysmal epileptiform abnormalities in the evaluation of patients for epilepsy surgery. Historically, electroencephalography (EEG) and evoked potentials (EPs) have performed these functions. However, both often required direct intracranial recording for precise localization. Magnetoencephalography (MEG) takes advantage of the fact that neuromagnetic signals penetrate the skull and scalp without distortion. The magnetic source image (MSI) is created when the MEG data is superimposed on a magnetic resonance image (MRI). REVIEW SUMMARY: MEG performs noninvasive functional imaging by recording the magnetic flux on the head surface associated with electrical currents in activated sets of neurons. MEG has rapidly evolved in the last 2 decades because of the introduction of whole head systems and advances in computer technology. MEG is now the imaging modality of choice where a precise and high degree of localization is required. MEG can be used to localize the primary sensory cortices (visual, auditory, or somatosensory), areas involved with receptive language function, the irritative zone in epilepsy patients, and identify children with anomalous language development. This article reviews the basis of MEG, the instrumentation used, the clinical applications and current limits of the technology. CONCLUSION: MEG studies can now be performed on a routine basis as a clinical tool. MEG is now indicated for: 1) localization of the irritative zone in lesional and nonlesional epilepsy surgery patients, 2) functional mapping of eloquent cortex, and 3) assessment of normal and abnormal language development. In the future MEG may help the understanding of normal development and reorganization after brain injury. The neurologist can use MEG data to complement structural and metabolic imaging techniques.

Brain Mapping↗

PubMed2003

Differential brain activation patterns during perception of voice and tone onset time series: a MEG study.

Evoked magnetic fields were recorded from 18 adult volunteers using magnetoencephalography (MEG) during perception of speech stimuli (the endpoints of a voice onset time (VOT) series ranging from /ga/ to /ka/), analogous nonspeech stimuli (the endpoints of a two-tone series varying in relative tone onset time (TOT), and a set of harmonically complex tones varying in pitch. During the early time window (approximately 60 to approximately 130 ms post-stimulus onset), activation of the primary auditory cortex was bilaterally equal in strength for all three tasks. During the middle (approximately 130 to 800 ms) and late (800 to 1400 ms) time windows of the VOT task, activation of the posterior portion of the superior temporal gyrus (STGp) was greater in the left hemisphere than in the right hemisphere, in both group and individual data. These asymmetries were not evident in response to the nonspeech stimuli. Hemispheric asymmetries in a measure of neurophysiological activity in STGp, which includes the supratemporal plane and cortex inside the superior temporal sulcus, may reflect a specialization of association auditory cortex in the left hemisphere for processing speech sounds. Differences in late activation patterns potentially reflect the operation of a postperceptual process (e.g., rehearsal in working memory) that is restricted to speech stimuli.

Adult↗