Despite the availability of efficient tear substitutes, many patients with dry eye syndrome experience severe corneal injuries and a subsequent loss of vision. Surgical techniques using mayor salivary glands to provide a substitute for tears have been reported; with this technique the drainage of saliva goes into the conjunctival fornix, permitting corneal and conjunctival humidification. The authors describe a new surgical approach in which minor salivary glands are autotransplanted into the conjunctival fornix by means of a graft of the intraoral mucosa-transporting salivary glands. This approach was used in a 56-year-old woman with a 2-year history of refractory and pharmacologically untreatable dry eye syndrome caused by Sjögren's syndrome. The right eye had more severe corneal and conjunctival lesions than did the contralateral one, so the treatment was planned in the right eye only. A weekly follow-up during the first 6 months confirmed the significant improvement of dry eye symptoms in the surgically treated eye. Three months after surgery, a biopsy was performed in the minor salivary gland graft, and the histologic findings revealed the presence of glandular acinus, duct with mucin content, and lymphocyte infiltration. The significant improvement obtained in this patient suggests that the secretion from the grafted salivary minor glands was better in promoting homeostasis of the ocular surface than are artificial tears. This may be explained by: (1) The lacrimal and salivary secretions contain biologically active constituents that may protect from infection and promote normal growth epithelium; (2) The secreted mucin is thought to coat the epithelial surface, reducing the high surface tension of the eye wetted by aqueous tears; (3) The thick secretions of the minor gland might act in reducing the evaporation of the underlying tear layer and form a hydrophobic barrier along the lid margin that can retain the lid margin tear string and prevent its flow onto the skin. Minor gland salivary autotransplant is a new surgical technique with effectiveness demonstrated in one patient, but the scientific explanation is not clear; additional experience with more cases could confirm the initial success.
The use of domain knowledge for program comprehension has been advocated by many authors. However, as far as we know, most of the analysis techniques using domain knowledge are static, it seems that dynamic analyses have not yet taken full advantage of any domain knowledge. This might be a consequence of ontologies, the most common technique for domain knowledge representation, being static by nature. In this article we present a new kind of dynamic analysis that attempts to use domain knowledge from two ontologies: that of the domain concepts and another one we called the "Ontology of Domain Actions". To take advantage of this later source of knowledge, we had to specify what actions were expected to be performed by the software at any moment in time. This has been done using a variant of the CRC cards formalism. As a result, we are able to match the actions actually performed by the software with expectations using dynamic analysis based on the action ontology.
RESUMENObjetivo: El límite inferior de edad del donante corneal resulta polémico. A pesar de la mayor densidad endotelial neonatal existen problemas quirúr-gicos (anatomía corneal infantil), refractivos (tendencia a miopización) y postoperatorios (mayor inmunogenicidad). Se analizan dos casos con empleo de tejido donante de 4 meses, con resultado refractivo postoperatorio atípico en ambos y desproporcionada respuesta inmune en uno. A propósi-to de los mismos, se realiza una revisión sobre el uso de injertos de donantes pediátricos en la queratoplastia penetrante. Métodos: Se presentan dos pacientes jóvenes con queratocono intervenidos de queratoplastia penetrante con injerto donante de 4 meses y alta densidad endotelial (4.500 cel/mm 2 ). Resultados: En el postoperatorio inmediato presentaron una elevada hipermetropía (se redujo posteriormente) con escaso astigmatismo. En uno aumentó notablemente el astigmatismo tras la excisión de sutura precisando queratotomía arcuata y puntos de refuerzo, mostrando al año y medio injerto transparente, agudeza visual corregida de V=1 y densidad endotelial alta (4.300 cel/mm 2 ). El otro presentó a los 7 meses un rechazo con edema del REVISIÓN ABSTRACT Objective: The lower recommended age of the donor cornea is a controversial matter. Although newborn corneas have a high endothelial cell density, there are anatomical, refractive (myopic shift) and postoperative problems. Two cases are analyzed; one had an atypical refractive result and the other an unexpectedly severe immune response. We also review the use of pediatric donor corneas in penetrating keratoplasty. Methods: Two young patients with keratoconus, in whom a penetrating keratoplasty was done using a 4-month-old newborn corneal donor with high endothelial cell density (4.500 cell/mm 2 ) are reported. Results: In the early postoperative period, both had high hypermetropy with weak astigmatism that improved over the next few months. In one patient a marked increase in the astigmatism after removal of the continuous suture was observed. One and a half years after the penetrating keratoplasty there was V=1 corrected vision and the endothelial population was almost unchanged (4,300 cell/mm 2 ). The other patient suffered an allograft reaction with corneal oedema in the seventh postoperative month, and subsequent rupture of the continuous suture made its early removal necessary. The oedema par-
In this paper we first propose a source code comprehension model built as a hierarchy of three abstraction levels from the source code to the purpose (goal) of the program. The elements belonging to each layer have been precisely defined as well as their links to the elements in the adjacent layers. Consequently this model allows to bridge the semantic gap between the purpose of the program defined in business terms and the code that implements it. The model leverages two ontologies: an action ontology, which is specific to our approach, and a domain concept ontology. Next this model has been implemented as a tool under Eclipse and two experiments have been performed to assess the relevance of our approach in the maintenance of a large-scale program. The results of this experiment are very encouraging. The contribution of the paper is the presentation of our program comprehension model built on a novel approach based on an action ontology, the description of the tool we developed to assess the relevance of model and the testing of the latter with two controlled experiments.
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