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Biomedical subjects

F E León-S

Publications and source records attributed to F E León-S.

10 recordsLinked to original sources

[Prions, infections and confusions in the "transmissible" spongiform encephalopathies. The other evidence-based science. III. Review].

There are some neurological disorders with a pathological hallmark called spongiosis which include Creutzfeld-Jakob disease and its new variant, the Gertsmann-Straussler-Scheinker Syndrome and the Fatal Familial Insomnia in humans; and Scrapie and Bovine Spongiform Encephalopathy, among others, in animals. The etiological agent has been considered either transmissible or hereditary or both. Curiously, this agent has no nucleic acids, is impossible to filter, is resistant to inactivation by chemical means, has not been cultured and is unobservable at electron microscopy. All of these facts have led to some researches to claim that these agents are similar to viruses appearing in computers. However, after almost fifty years of research, is still not possible to explain why and how such elements produce the diseases commented about. On the contrary, during these years have been possible to know that these entities called slow viral infections, transmissible amyloidosis, transmissible dementia, transmissible spongiform encephalopathies or prion diseases appear in individuals with genetical predispositions exposed to several worldwide immunological stressors. The possibility that prions are the consequence and not the cause of these diseases in animals and man is day by day more reliable, and supports the suggestion that a systematic intoxication due to pesticides as well as mycotoxin ingestion, produced mainly by different molds such as Aspergillus, Penicillium or Fusarium, seem to be the true etiology of these neurodegenerative disorders.

Adolescent↗

[Anatomical and pathological study of the temporomandibular joint disk in Colombian individuals].

BACKGROUND: The temporomandibular joint is an oval fibrous plate that completely divides the joint and accommodates irregularities existent in the bone articular surfaces. AIM: To study the frequency of temporomandibular joint disk abnormalities among Colombian subjects. MATERIAL AND METHODS: We studied 120 temporomandibular joint disks obtained from fresh cadavers arrived in the Instituto de Medicina Legal, in Cali Colombia. These were analyzed according to subject's dental status and age. RESULTS: Nineteen percent of disks had small erosions. In 7.5% of disks there were wider erosions or perforations. Twenty six percent of discs were very thin and this alteration was seen mostly in people aged 50 years or older. CONCLUSIONS: These results are intermediate between those who claim that disk perforations are rare and those who had shown tile opposite. The loss of dental pieces seems to be a risk factor leading to such disk perforation.

Adult↗

Recent concepts in the pathophysiology and evaluation of spasticity.

Spasticity is still a challenge to clinicians and scientists. The participation of Ia, Ib, II, III and IV afferents pathways, as well as those related with presynaptic inhibition. Renshaw cells modulation, and alpha and gamma motoneurons hyperexcitability, in this medical problem are reviewed. A brief overview on the more common neurophysiological tests performed during the evaluation of human spasticity is presented.

Afferent Pathways↗

[The possible transpacific travel of the adult T-cell leukemia virus I].

Genetical and archeological similarities in both Japanese and South American populations have been described. These facts along with the recent seroepidemiological studied on retroviruses performed in some of those racial groups, and published up to 1993, allow us to suggest that these retroviruses likely arrived to South America, not only from Africa, but also from The Far East since 6000 years ago or earlier. It could occur following the sea-currents directly.

Archaeology↗

[Tropical spastic paraparesis (HAM/TSP) in different regions of the world. Subclinical and geographic differences in neurophysiologic studies].

Tropical spastic paraparesis is the same clinical entity all over the world. It has been suggested that some clinical presentation differences are due to not well defined environmental factors that act along with the virus, modifying the start and progression of the disease. We analyzed 25 publications on the disease coming from different parts of the world, aiming to unravel regional differences. In these reports, we found different degrees of subclinical abnormalities in visual and somatosensory evoked potentials, nerve conduction studies, superior and inferior limb F wave and electromyography. It is concluded that genetic, environmental and even cultural factors may influence the clinical presentation of tropical spastic paraparesis and explain the detected differences in the reports analyzed in this study.

Electromyography↗

Antero-posterior localization of the pyramidal tract in the internal capsule in a living patient.

A lacunar infarction occurred in the posterior limb of the internal capsule in a 33-years-old Colombian woman, showed an antero-posterior (A-P) course of the corticospinal pathway. Anatomical and histological studies had suggested this course, but to the author's knowledge, this could be the first reported case of a living patient with such features, confirming those previous reports about them.

Adult↗

[Chronic myasthenia gravis mimicking muscular dystrophy, in eastern Colombia].

INTRODUCTION. Myasthenia gravis is an apparently well-defined neuromuscular disease with some variants, including one recently described as chronic myasthenia gravis. CASE REPORT. We present a 22 year old Columbian woman who complained of progressive weakness for the previous four years, affecting her pelvic and shoulder girdles but with no clinical involvement of the extra-ocular muscles. Repetitive stimulation of the neuro-muscular junction of the abductor digiti quinti muscle was negative, but positive for myasthenia gravis in the trapezius muscle and the right orbital eye muscles. Her symptoms improved and the clinical neurophysiological studies were normal again after treatment with pyridostigimine, which confirmed the diagnosis.

Adult↗