Studies of the Epitopes of Amoxicillin by Monoclonal Antibodies.

Four different mice monoclonal antibodies to amoxicillin (AX) were studied (AO 25.2, AO 6.2, AO 21.1, and AO 3.2). The specificity was determined by enzyme-linked immunosorbent assay inhibition using in the fluid phase free and conjugated monomers of AX, ampicillin, and benzylpenicillin with ε-aminocaproic acid. The monoclonal AO 25.2 (IgM isotype) recognized a chemical structure common to all penicillins used, presumably the thiazolidine ring. AO 6.2 (IgE) and AU 3.2 (IgG2a recognized mainly the side chain of AX and the clone AO 21.1 (IgG3) required for optimal inhibition of the conjugated monomer of AX, indicating that both the side chain and the new antigenic determinant were required for optimal inhibition. These results indicate that there are differences in the specificities of these antibodies and that the different parts of the AX molecule contribute to a different extent to the antigen-binding site.

Comparison of the effects of nerve growth factor and superoxide dismutase on vascular extravasation in experimental burns.

Superoxide dismutase (SOD), a free-radical scavenger, inhibits the increase of vascular permeability in experimental burn lesions in rats. In this study the aim was to determine whether Nerve Growth Factor (NGF), which has been implicated in the modulation of some inflammatory reactions, behaves in an analogous way. The study compares the haematocrit (Ht) and haemoglobin (Hb) variations in three groups of rats treated respectively with saline solution, SOD and NGF, immediately after causing a 25 per cent dermal burn injury. Statistical comparison (Student's t test) of the Ht and Hb variations between the Control group (Ht and Hb increase) and the NGF group (Ht and Hb decrease), shows significant differences in the intervals between 15 and 60 min (P < 0.01) and between 60 and 120 min (P < 0.05). Although SOD is able to control extravasation in the immediate postburn period (basal-15 min), NGF has a comparable effect in subsequent periods. The overall action of NGF shows that this agent is able to maintain Ht and Hb values at basal levels even after 120 min postburn. These results seem to be the first evidence of an inhibitory effect of NGF on the vascular permeability in burn lesions.

Role of mast cells in the pathogenesis of postburn inflammatory response: reactive oxygen species as mast cell stimulators.

Thermal trauma has a direct effect on mast cells, triggering the secretion of histamine. This secretion leads to an enhanced xanthine oxidase activity and an increased production of reactive oxygen species (ROS), the latter being produced after burns through differing mechanisms. As ROS have been shown to have deleterious effects on cellular membranes, a lesion of the mast cell membrane could close the circle of autoinjury due to the vasoactive actions of mast cell mediators. Our studies were designed to assess the potentiality of ROS as stimulators of mast cell degranulation after burns by comparing two groups of rats treated, respectively, with SOD and saline solution after a scald injury. Plasma levels of tryptase and histamine were analyzed as markers of mast cell activity. A comparison of the mean increases of tryptase between baseline and 3-h postburn levels in the two groups shows significant differences (p < 0.001) (control: 0.13+/-0.04, SOD: 0.03+/-0.01). When comparing the mean increases between the baseline and 3 h postburn levels of histamine in the two groups, significant differences were also found (p < 0.001) (control group: 2.70+/-0.57. SOD group: 1.22+/-0.32). The lower levels of histamine and tryptase induced by SOD provides indirect evidence that ROS are involved in the process, causing the release of such mediators by mast cells, which may in turn suggest that ROS can act as stimulators of mast cell degranulation in burns.

Obstrucción intestinal producida por la larva de Anisakis / Intestinal obstruction produced by Anisakis larvae

Introducción. Se presentan 8 casos de obstrucción intestinal mecánica simple producidos por Anisakis, diagnosticados en nuestro hospital durante los últimos 2 años. Pacientes y método. Los enfermos fueron diagnosticados, en el servicio de urgencias, de obstrucción intestinal mecánica simple; todos ellos referían ingestión de pescado crudo 36-48 h antes del comienzo del cuadro clínico. En un enfermo era el tercer cuadro de obstrucción intestinal que padecía durante los últimos 6 meses. El diagnóstico se realizó por la clínica, antecedentes de ingesta de pescado crudo y presencia en el hemograma de una leucocitosis moderada (12.000- 14.500). En 4 casos destacaba una eosinofilia superior al 8 por ciento. Las pruebas inmunológicas realizadas fueron: in vivo, la prueba cutánea llevada a cabo mediante el test de Prick, y la prueba in vitro, mediante la determinación de IgE específica e IgE total. Todas fueron positivas. Las pruebas de imagen realizadas fueron: radiología simple de abdomen en la que se apreciaban niveles hidroaéreos dependientes de asas de intestino delgado dilatadas y ecografía abdominal, que se realizó en 6 pacientes en los que se observaron signos de enfermedad inflamatoria en el íleon terminal. Resultados. El tratamiento de la obstrucción intestinal fue en todos los casos conservador. Una vez pasado el cuadro agudo se instauró tratamiento preventivo para la larva del Ani sakis. Conclusiones. La larva de Anisakis, que era rara en España, comienza a ser más frecuente como se demuestra en el número de trabajos que se han publicado en los últimos 2 años. Se puede concluir que Anisakis simple es un factor etiológico de la obstrucción intestinal mecánica simple y sugerimos tenerlo en consideración en los servicios de cirugía de urgencia ante la presencia de enfermos con cuadros de obstrucción intestinal, especialmente después de la ingestión de pescado (AU)