Orbital peripheral nerve sheath tumors.

Peripheral nerve sheath tumors of the orbit and ocular adnexa are a rare group of neoplasms hallmarked by nonspecific clinical presentations, variable tumor locations, challenging therapeutic efforts, and occasional diagnostic dilemmas. We review these tumor types and provide an updated summary on their clinical, histopathologic, radiological, and emerging molecular features.

Congenital pupillary-iris-lens membrane with goniodysgenesis: histopathologic findings in an enucleated eye.

A 10-year-old boy with clinically confirmed congenital pupillary-iris-lens membrane with goniodysgenesis underwent light microscopic examination of the enucleated eye. The anterior segment changes consisted of the absence of the iridial pupillary sphincter muscle and dilator muscle processes. Endothelialization and descemetization of the anterior chamber angle and the anterior surface of the iris covered the original eccentric pupillary opening (occlusio pupillae), but grew around the fibrotic edges of the surgically created, patent pseudopupil, probably secondary responses to surgery. The anterior chamber findings in this case establish a localized syndrome that includes absence of the pupillary sphincter and dilator muscle processes. Incomplete development of the iris may be partly attributable to an abnormality of stromal development and inductions by the anterior neuroectodermal layer, together with anomalies of the pupillo-iridial vasculature.

A case of autoimmune-related retinopathy and optic neuropathy syndrome treated by autologous nonmyeloablative hematopoietic stem cell transplantation.

Autoimmune-related retinopathy and optic neuropathy (ARRON) syndrome is characterized by visual loss and often the presence of antibodies against retinal or optic nerve antigens in the absence of cancer. Limited success has been reported in treatment of ARRON syndrome with medications that suppress the immune system. In many patients, current strategies are insufficient to control the disease. A 47-year-old woman with progressive visual and hearing loss attributed to ARRON syndrome that was resistant to conventional therapies underwent autologous hematopoietic stem cell transplantation (HSCT). Clinical manifestations appeared to stabilize. This report suggests that autologous HSCT may have a therapeutic role in ARRON syndrome.

Basal cell carcinoma of the eyelid with exceptional histomorphologic expressions.

A basal cell carcinoma of the eyelid had unique and potentially confusing histopathologic features. The tumor displayed a carcinoma in situ pattern with replacement of an extensive segment of the tarsal epithelium by neoplastic basaloid cells, a finding to the best of the authors' knowledge that has not been previously documented. Within the infiltrating component of the dermis were classical solid basaloid nests and lobules; they were accompanied, however, by a separate and exceptionally prominent component of duct-like (pseudoglandular) units mimicking a microcystic adnexal carcinoma.

Exaggerated postsurgical inflammation in a patient with insufficiently treated Addison disease.

A patient with Addison disease developed fever, pain, and marked orbital inflammation 3 days after evisceration in the setting of perforated corneal ulcer. He was treated for presumed orbital cellulitis without improvement. Increasing the corticosteroid dose for his Addison disease resulted in complete resolution of the inflammation.

Subepidermal calcified nodule of the eyelid.

Subepidermal calcified nodule, a rare form of calcinosis cutis, is a benign lesion of the eyelid that occurs in children. We report a case of a 9-year-old boy with a nodule of the right upper eyelid simulating Molluscum contagiosum. The histopathologic examination of the excised nodule confirmed the diagnosis.

Kinetic and stability properties of Penicillium chrysogenum ATP sulfurylase missing the C-terminal regulatory domain.

ATP sulfurylase from Penicillium chrysogenum is a homohexameric enzyme that is subject to allosteric inhibition by 3'-phosphoadenosine 5'-phosphosulfate. In contrast to the wild type enzyme, recombinant ATP sulfurylase lacking the C-terminal allosteric domain was monomeric and noncooperative. All kcat values were decreased (the adenosine 5'-phosphosulfate (adenylylsulfate) (APS) synthesis reaction to 17% of the wild type value). Additionally, the Michaelis constants for MgATP and sulfate (or molybdate), the dissociation constant of E.APS, and the monovalent oxyanion dissociation constants of dead end E.MgATP.oxyanion complexes were all increased. APS release (the k6 step) was rate-limiting in the wild type enzyme. Without the C-terminal domain, the composite k5 step (isomerization of the central complex and MgPPi release) became rate-limiting. The cumulative results indicate that besides (a) serving as a receptor for the allosteric inhibitor, the C-terminal domain (b) stabilizes the hexameric structure and indirectly, individual subunits. Additionally, (c) the domain interacts with and perfects the catalytic site such that one or more steps following the formation of the binary E.MgATP and E.SO4(2-) complexes and preceding the release of MgPPi are optimized. The more negative entropy of activation of the truncated enzyme for APS synthesis is consistent with a role of the C-terminal domain in promoting the effective orientation of MgATP and sulfate at the active site.

ATP sulfurylase from the hyperthermophilic chemolithotroph Aquifex aeolicus.

ATP sulfurylase from the hyperthermophilic chemolithotroph Aquifex aeolicus is a bacterial ortholog of the enzyme from filamentous fungi. (The subunit contains an adenosine 5'-phosphosulfate (APS) kinase-like, C-terminal domain.) The enzyme is highly heat stable with a half-life >1h at 90 degrees C. Steady-state kinetics are consistent with a random A-B, ordered P-Q mechanism where A=MgATP, B=SO4(2-), P=PP(i), and Q=APS. The kinetic constants suggest that the enzyme is optimized to act in the direction of ATP+sulfate formation. Chlorate is competitive with sulfate and with APS. In sulfur chemolithotrophs, ATP sulfurylase provides an efficient route for recycling PP(i) produced by biosynthetic reactions. However, the protein possesses low APS kinase activity. Consequently, it may also function to produce PAPS for sulfate ester formation or sulfate assimilation when hydrogen serves as the energy source and a reduced inorganic sulfur source is unavailable.