Intraocular penetration of toxic substances
West Indian med. j
; West Indian med. j;48(suppl.3): 16, July 1999.
Article
em En
| MedCarib
| ID: med-1213
Biblioteca responsável:
JM3.1
Localização: JM3.1; R18.W4
ABSTRACT
PURPOSE:
The seriousness of ocular alkali burns has been linked to the rapidity with which the alkali enters the eye. The authors report the results of an experimental study on intraocular ammonia penetration. MATERIALS ANDMETHODS:
23 eyes of New Zealand albino rabbits were burned by applying for one minute 100 ul of a solution titrating 15.3 percent of ammonia. A pH meter probe was inserted into the anterior chamber beforehand to permit pH measurements every 5 seconds. Experiments were carried out after 1,3,5,10 and 30 minutes. The ammonia concentration was measured at the end of the experiment by puncturing the anterior chamber.RESULTS:
The pH increased 1 to 3 minutes after applying ammonia on the cornea, reaching a maximum (mean) of 10 five to six minutes later, before an exponential decrease. After 30 minutes, the pH was always more than the physiological pH. The penetration ratio of ammonia through the cornea is about 11 percent. At 30 minutes, the concentration of ammonia is low. The pH observed differs from the calculated pH.DISCUSSION:
The difference between observed and calculated pH indicates increases with an intervening plateau, showing the existence of two successive acid-base chemical reactions between ammonia and two types of acid. In addition, the amount of protein destroyed by ammonia can be calculated.CONCLUSIONS:
These data show for the time the possibility of calculating the density of proteins destroyed in vivo by a base penetrating the anterior chamber. This opens the possibilty of interesting research work, because it is possible to relate the density of proteins destroyed in the eye to the pK of this base, and to forecast the potential danger of a base of biological tissues.(AU)
Buscar no Google
Coleções:
01-internacional
Base de dados:
MedCarib
Assunto principal:
Queimaduras Químicas
/
Queimaduras Oculares
/
Substâncias Tóxicas
Tipo de estudo:
Observational_studies
Limite:
Humans
Idioma:
En
Revista:
West Indian med. j
Ano de publicação:
1999
Tipo de documento:
Article