Lateral canthotomy and cantholysis: emergency management of orbital compartment syndrome.

BackgroundOrbital compartment syndrome is a sight-threatening emergency. Vision may be preserved when timely intervention is performed.ObjectiveTo present a case of orbital compartment syndrome caused by traumatic retrobulbar hemorrhage and the procedure of lateral canthotomy and cantholysis, reviewed with photographic illustration.DiscussionLateral canthotomy and cantholysis are readily performed at the bedside with simple instruments. The procedure may prevent irreversible blindness in cases of acute orbital compartment syndrome.ConclusionsEmergency physicians should be familiar with lateral canthotomy and cantholysis in the management of orbital compartment syndrome to minimize the chance of irreversible visual loss

Lateral canthotomy and cantholysis: emergency management of orbital compartment syndrome.

BackgroundOrbital compartment syndrome is a sight-threatening emergency. Vision may be preserved when timely intervention is performed.ObjectiveTo present a case of orbital compartment syndrome caused by traumatic retrobulbar hemorrhage and the procedure of lateral canthotomy and cantholysis, reviewed with photographic illustration.DiscussionLateral canthotomy and cantholysis are readily performed at the bedside with simple instruments. The procedure may prevent irreversible blindness in cases of acute orbital compartment syndrome.ConclusionsEmergency physicians should be familiar with lateral canthotomy and cantholysis in the management of orbital compartment syndrome to minimize the chance of irreversible visual loss

Tp53 deletion in B lineage cells predisposes mice to lymphomas with oncogenic translocations

Inactivating Tp53 mutations are frequent genetic lesions in human tumors that harbor genomic instability, including B lineage lymphomas with IG translocations. Antigen receptor genes are assembled and modified in developing lymphocytes by RAG/AID-initiated genomic rearrangements that involve the induction of DNA double strand breaks (DSBs). Although TP53 inhibits the persistence of DSBs and induces apoptosis to protect cells from genomic instability and transformation, the development of spontaneous tumors harboring clonal translocations has not been reported in mice that only lack wild-type Tp53 protein or express Tp53 mutants. Tp53-deficient (Tp53-/-) mice succumb to T lineage lymphomas lacking clonal translocations but develop B lymphoid tumors containing immunoglobulin (Ig) translocations upon combined inactivation of DSB repair factors, RAG mutation or AID overexpression; mice expressing apoptosis-defective Tp53 mutants develop B cell lymphomas that have not been characterized for potential genomic instability. As somatic rather than germline inactivating mutations of TP53 are typically associated with human cancers and Tp53 deletion has cellular context dependent effects upon lymphocyte transformation, we generated mice with conditional Tp53 deletion in lineage-committed B lymphocytes to avoid complications associated with defective Tp53 responses during embryogenesis and/or in multi-lineage potential cells and, thereby, directly evaluate the potential physiological role of Tp53 in suppressing translocations in differentiated cells. These mb1-cre:Tp53flox/flox mice succumbed to lymphoid tumors containing Ig gene rearrangements and immuno-phenotypes characteristic of B cells from various developmental stages. Most mb1-cre:Tp53flox/flox tumors harbored clonal translocations, including Igh/c-myc or other oncogenic translocations generated by the aberrant repair of RAG/AID-generated DSBs. Our data indicate that Tp53 serves critical functions in B lineage lymphocytes to prevent transformation caused by translocations in cell populations experiencing physiological levels of RAG/AID-initiated DSB intermediates, and provide evidence that the somatic TP53 mutations found in diffuse large B-cell lymphoma and Burkitt's lymphoma may contribute to the development of these human malignancies