RESUMEN
The genotoxic potential of the carcinogenic mycotoxin of ochratoxin A (OTA) has been investigated by means of an in vitro micronucleus assay, an endpoint for genotoxicity which has not been studied previously for OTA. OTA was found to induce dose-dependently micronuclei (MN) in cytokinesis-blocked binucleated ovine seminal vesicle (OSV) cell cultures, which had been treated with mycotoxin (12-30 microM) for 6 h in medium containing 10% fetal calf serum. For comparison, OSV cells were treated with colcemid (0.02-0.06 micrograms/ml), or 4-nitroquinoline N-oxide (NQO; 0.5 microM), a typical aneugen and clastogen, respectively. All test compounds increased the frequency of MN in OSV cells, the highest level being induced by 10 microM OTA. When MN were characterized by indirect immunofluorescence microscopy using anti-kinetochore (CREST) antibodies, the majority of MN in colcemid-treated cells was CREST-reactive (> 70% kinetochore positive); as expected, this fraction was < 10% for the NQO-treatment group. In cells treated with OTA the fraction of kinetochore positive MN was similar (33-40%) to that observed in solvent controls (38%). These data indicate that OTA induces MN apparently by a mixed, although predominantly clastogenic mode of action. OSV cells lack monooxygenase activity but express high prostaglandin H synthase (PGHS) activity. When cells were treated with OTA in the presence of indomethacin (10 and 10 microM), a well known inhibitor of PGHS, the frequency of MN induced by OTA was not decreased, but rather increased. This indicates that metabolic activation of OTA by PGHS seems not to be required for genotoxicity. The increased MN induction in OSV cell cultures is most likely due to competition in indomethacin with OTA for binding to serum proteins thus raising the fraction of free mycotoxin.
Asunto(s)
Carcinógenos/toxicidad , Micronúcleos con Defecto Cromosómico/efectos de los fármacos , Micotoxinas/toxicidad , Ocratoxinas/toxicidad , Vesículas Seminales/efectos de los fármacos , 4-Nitroquinolina-1-Óxido/toxicidad , Animales , Anticuerpos Monoclonales , Antineoplásicos Fitogénicos/toxicidad , Células Cultivadas , Inhibidores de la Ciclooxigenasa/toxicidad , Demecolcina/toxicidad , Relación Dosis-Respuesta a Droga , Indometacina/toxicidad , Masculino , Micronúcleos con Defecto Cromosómico/metabolismo , Microscopía Fluorescente , Mutágenos/toxicidad , Prostaglandina-Endoperóxido Sintasas/metabolismo , Vesículas Seminales/citología , Ovinos , Coloración y EtiquetadoRESUMEN
The performance of 38 male third- and fourth-grade reading disabled/poor decoders and above-average readers/good decoders was compared on a series of six measures of phonological awareness, including tasks that required the ability to segment, blend, and manipulate phonemes. Performance on these tasks was also correlated with phonetic decoding of pseudowords. Significant but varying intercorrelations were obtained among tasks in both groups. For the poor decoders, deletion was the most highly correlated with the other tasks. However, all good decoders performed at ceiling level on this task. For the poor decoders, deletion was significantly correlated with phonetic decoding (r = .74 and r = .78 for timed and untimed decoding measures, respectively). While all good decoders had good phonological awareness, not all those with good phonological awareness were good decoders. The results suggest that tasks that require blending and manipulation of phonemes, in addition to segmentation, may predict decoding ability best.
Asunto(s)
Concienciación , Cognición , Dislexia/rehabilitación , Educación Especial , Fonética , Lectura , Niño , Curriculum , Humanos , MasculinoRESUMEN
This article reviews the Tenth Annual Report to Congress on the Implementation of The Education of the Handicapped Act (EHA), covering the 1986-1987 school year. In addition to reporting the current status of services (i.e., numbers of students served, their placement, resources allocated and needed for their support), the report also discusses and cites data pertinent to (a) transition from secondary education; (b) state and federal efforts anticipating full implementation of preschool special education services under Public Law 99-457; and (c) the classification of students with learning disabilities. Some directions for research on special education at a national level are suggested.
Asunto(s)
Educación Especial/legislación & jurisprudencia , Adolescente , Adulto , Niño , Preescolar , Humanos , Discapacidades para el Aprendizaje/diagnóstico , Abandono Escolar , Estados UnidosRESUMEN
From 1981-1988, 3433 women were fitted with a cavity-rim cervical cap in a Food and Drug Administration-approved study. The estimated first-year pregnancy risk was 11.3% (95% confidence limits 10.0-12.8), with risks of 8.3 and 3.8% for user and method failures, respectively. Women who were younger, less educated, and more sexually active, and who intended to have children in the future, had higher pregnancy risks. "Near-perfect" users, ie, individuals who wore the cap for a maximum of 72 hours, used spermicide 100% of the time, and did not report unprotected sexual intercourse, had half the first-year pregnancy risk of others (6.1 versus 11.9%). There were no serious medical or gynecologic complications associated with cap use, although over 20% of users reported problems with cap dislodgment during or after intercourse, cap malodor, or partner discomfort.