Orbital Reconstruction via Deformable Titanium Mesh Following Spheno-Orbital Meningioma Resection: Ophthalmic Presentation and Outcomes.

PURPOSE: To present a surgical approach to reconstruction of the bony orbit following resection of spheno-orbital meningioma utilizing deformable titanium mesh while emphasizing the ophthalmic presentation and outcomes of the repair. METHODS: A retrospective chart review received International Review Board approval, and 20 patients met the inclusion criteria. All patients underwent resection of spheno-orbital meningioma followed by orbital reconstruction with deformable titanium mesh. Pre- and postoperative ophthalmic exam findings were recorded. Outcome measures include Snellen visual acuity, performance on automated Humphry 30-2 perimetry, extraocular motility, Hertel exophthalmometry, associated complications, and recurrence. A literature review of the use of titanium to reconstruct the orbit following resection of spheno-orbital meningioma was performed. RESULTS: Visual acuity improved (9/20) or remained the same (8/20) in 85% of patients. Fifteen of the 20 patients had pre- and postoperative visual fields performed, and 93% (14/15) experienced substantial improvement or no change with full fields. Of the 12 patients who had extraocular motility disturbance following surgery, 25% (3/12) had preexisting defects that did not change, 58% (7/12) returned to normal, and 17% (2/12) had new onset dysfunction that did not improve. Proptosis was reduced by a mean of 4.4 mm. Complications were rare and inconsequential, and recurrence was observed in 20% (4/20) at an average of 43 months following surgery. CONCLUSIONS: Orbital reconstruction using deformable titanium mesh is both safe and effective in the setting of resection of spheno-orbital meningioma. This study is the largest known report of orbits reconstructed with deformable titanium mesh in the available literature.The ophthalmic presentation of spheno-orbital meningioma and postoperative results are presented following description of orbital reconstruction utilizing deformable titanium mesh.

Evisceration With Injectable Hydrogel Implant in a Rabbit Model.

PURPOSE: To determine the safety, durability, and biocompatibility of 2.5% polyacrylamide hydrogel (Aquamid, Specialty European Pharma, Ltd., London, UK) as an injectable viscoelastic implant following evisceration in a rabbit model. METHODS: The protocol was reviewed and approved by the Wake Forest Institutional Animal Care and Use Committee. Adult New Zealand rabbits underwent cornea-sparing evisceration of the right eye with injection of 2.5% polyacrylamide hydrogel implant. The rabbits were sacrificed after 2 weeks (n = 1), 5 weeks (n = 2), 12 weeks (n = 3), 25 weeks (n = 3), and 1 year (n = 3) to evaluate the implant volume and host reaction to the implant. Both eyes were enucleated and their diameters were measured. The eviscerated eyes were fixed in formalin and processed using routine histopathologic methods to assess inflammatory reaction and vascularization. RESULTS: The implant material was well tolerated with a moderate giant cell reaction seen at 6 weeks that improved over time. Extensive vascularization of the implant was noted starting at 6 weeks. There was excellent maintenance of globe volume that did not diminish over time. The relative diameters of the eviscerated eyes compared with control were 89 ± 6% (mean% ± SD) at 12 weeks (n = 3), 94 ± 2% at 25 weeks (n = 3), and 93 ± 4% at 1 year (n = 3). CONCLUSION: With further study, injectable 2.5% polyacrylamide hydrogel may provide an excellent alternative to solid orbital implants. The implant material was universally well tolerated and maintained appropriate volume in the orbit for the study period of 1 year. Extensive vascularization of the implant was noted indicating biointegration.

Incidence of, risk factors for, and combined mechanism of late-onset open-angle glaucoma after vitrectomy.

PURPOSE: To estimate the incidence of and identify the risk factors for late-onset open-angle glaucoma (OAG) after uncomplicated pars plana vitrectomy (PPV). METHODS: All patients who underwent PPV at the Edward Harkness Eye Institute between January 1998 and January 2004 had at least 6 months of follow-up and did not have preexisting glaucoma or reason for secondary development of glaucoma were included. Retrospective cohort and matched case-control study designs were used. RESULTS: Of 285 vitrectomized eyes that met enrollment criteria, 11.6% (n = 33) developed glaucoma after vitrectomy. In the matched case-control analysis, the only variable that had a statistically significant association with the development of OAG was cataract extraction (CE), as compared with phakic status at the last follow-up (odds ratio = 16.4; 95% confidence interval, 2.1-127.4; P = 0.007). There was no difference in OAG development between eyes that had CE before or at the time of PPV and those that had it after PPV. The overall incidence of OAG development after PPV among all eyes, phakic eyes, and nonphakic eyes was 11.6%, 1.4%, and 15.0%, respectively. The difference in incidence between phakic and nonphakic eyes was statistically significant (P = 0.001). CONCLUSION: Lens extraction is a strong risk factor for the development of late-onset OAG after uncomplicated PPV. While the overall incidence of OAG development after PPV is substantial, it is more so among eyes that have had CE. The absence of substantial OAG incidence in phakic patients points toward a combined mechanism for late-onset post-PPV OAG involving PPV and CE at any time. Preoperative PPV counseling should include the risk of glaucoma development in addition to cataract development and the connection between the two. Patients who have undergone PPV, and especially those who also had CE in the same eye, should be carefully monitored for glaucoma.

Nondiagnostic conjunctival map biopsies for sebaceous carcinoma.

OBJECTIVE: To compare the prevalence of nondiagnostic conjunctival map biopsies in patients with extensive pagetoid sebaceous carcinoma (defined as involvement of 3 or 4 quadrants of the ocular surface) and in patients without extensive pagetoid tumor (defined as involvement of 1 or 2 quadrants of the ocular surface). METHODS: Retrospective medical record and pathologic specimen review of 20 patients treated for sebaceous carcinoma at a tertiary care center. Biopsies with artifactual loss of or damage to the epithelium were categorized as nondiagnostic. RESULTS: One hundred forty-four map biopsies were reviewed, an average of 7.2 (standard deviation [SD], 4.4) biopsies per patient. Sixteen patients had extensive pagetoid tumor, 4 did not. Fifteen percent of biopsies were nondiagnostic. The frequency of nondiagnostic biopsies in patients with and without extensive pagetoid tumor was 37% and 10%, respectively. The odds ratio of nondiagnostic biopsy in the setting of extensive pagetoid tumor was 5.9 (95% confidence interval, 2.3-15.6; P = .004). Six of the sixteen patients (38%) without extensive pagetoid tumor had at least 1 nondiagnostic biopsy, with an average of 1.8 (SD, 1.6) nondiagnostic biopsies per patient (22% of biopsies). Two of the 4 patients (50%) with extensive pagetoid tumor had at least 1 nondiagnostic biopsy, with an average of 5.5 (SD, 3.5) nondiagnostic biopsies per patient (57% of biopsies). CONCLUSIONS: Nondiagnostic, de-epithelialized conjunctival map biopsies are more common in patients with extensive pagetoid tumor than in those with limited or no pagetoid tumor. Artifactual epithelial loss may result from disruption of epithelial adhesion to the basement membrane by infiltrating tumor cells.

Anterior lamellar recession with buccal mucous membrane grafting for cicatricial entropion.

PURPOSE: To evaluate the use of anterior lamellar recession with buccal mucous membrane grafting for treatment of cicatricial entropion. METHODS: A retrospective interventional case series of 26 patients (35 eyelids) who underwent anterior lamellar recession with buccal mucous membrane grafting for cicatricial entropion. RESULTS: Thirty-five eyelids of 26 patients were treated for moderate to severe cicatricial entropion between 1992 and 2005. The most common underlying etiologies were ocular cicatricial pemphigoid (13 eyelids), blepharitis (7 eyelids), and Stevens-Johnson syndrome (5 eyelids). Treatment was defined as an anatomic success if no keratinized eyelid margin tissue was touching the ocular surface. The success rate of primary repair was 77% (27 of 35 eyelids) with a mean follow-up time of 2.5 +/- 1.9 years. Four eyelids (11%) underwent repeat grafting for recurrent entropion secondary to graft shrinkage (3 eyelids) and graft dislocation (1 eyelid) for a cumulative success rate of 89%. The remaining 4 eyelids (11%) had recurrent entropion that was managed surgically with a technique other than repeat grafting. The postoperative complications consisted of 1 case of wound site infection that was successfully treated with topical antibiotics and 1 case of mouth wound infection. Overall, there was a reduction in the frequency of patients reporting discomfort/foreign body sensation, tearing, photosensitivity, and pain following treatment. Corneal fluorescein staining improved postoperatively in 66% of eyes, stayed the same in 17%, and worsened in 17%. CONCLUSIONS: Anterior lamellar recession with buccal mucous membrane grafting is an effective surgical approach for the treatment of moderate to severe cicatricial entropion.

Tarsal dermoid cyst: clinical presentation and treatment.

The authors present 2 cases of eyelid dermoid cyst attached to tarsus in pediatric patients. Both patients were infants who presented with a firm, nontender upper eyelid mass firmly adherent to tarsus. In both cases, the lesion was excised en bloc, and histopathology revealed a dermoid cyst. To the authors' knowledge, there are no previously reported cases of tarsal dermoid cyst. These cases demonstrate the importance of including dermoid cyst in the differential diagnosis of a tarsus-based eyelid mass. Misdiagnosis may lead to incision and curettage, resulting in spillage of cyst contents and the risk of severe inflammation and scarring.

Primary cutaneous anaplastic large cell lymphoma of the medial canthus and orbit.

A 59-year-old man sought evaluation for a rapidly enlarging, nontender, ulcerated right medial canthal lesion unresponsive to antibiotics. Biopsy revealed CD30+ anaplastic large cell lymphoma. CT demonstrated contiguous spread in the orbit. Systemic evaluation for lymphoma was negative, and he underwent local radiotherapy. The lesion regressed completely, and he has remained disease free for 7 months. CD30+ anaplastic large cell lymphoma of the periocular skin and orbit are usually distinct, exceedingly rare entities; no reported cases had simultaneous involvement of both tissues. The authors present the first reported case, to their knowledge, of simultaneous skin and orbital involvement by anaplastic large cell lymphoma.

Heteromeric, but not homomeric, connexin channels are selectively permeable to inositol phosphates.

Previous work has shown that channels formed by both connexin (Cx)26 and Cx32 (heteromeric Cx26/Cx32 hemichannels) are selectively permeable to cAMP and cGMP. To further investigate differential connexin channel permeability among second messengers, and the influence of connexin channel composition on the selectivity, the permeability of inositol phosphates with one to four phosphate groups through homomeric Cx26, homomeric Cx32, and heteromeric Cx26/Cx32 channels was examined. Connexin channels were purified from transfected HeLa cells and from rat, mouse, and guinea pig livers, resulting in channels with a broad range of Cx26/Cx32 aggregate ratios. Permeability to inositol phosphates was assessed by flux through reconstituted channels. Surprisingly, myoinositol and all inositol phosphates tested were permeable through homomeric Cx32 and homomeric Cx26 channels. Even more surprising, heteromeric Cx26/Cx32 channels showed striking differences in permeability among inositol phosphates with three or four phosphate groups and among isomers of inositol triphosphate. Thus, heteromeric channels are selectively permeable among inositol phosphates, whereas the corresponding homomeric channels are not. There was no discernible difference in the permeability of channels with similar Cx26/Cx32 ratios purified from native and heterologous sources. The molecular selectivity of heteromeric channels among three inositol triphosphates could not be accounted for by simple connexin isoform stoichiometry distributions and therefore may depend on specific isoform radial arrangements within the hexameric channels. Dynamic regulation of channel composition in vivo may effectively and efficiently modulate intercellular signaling by inositol phosphates.

Isoelectric points and post-translational modifications of connexin26 and connexin32.

The isoelectric points of the gap junction proteins connexin26 (Cx26) and connexin32 (Cx32) were determined by isoelectric focusing in free fluids. The isoelectric points were significantly more acidic than predicted from amino acid sequences and different from each other, allowing homomeric channels to be resolved separately. The isoelectric points of the homomeric channels bracketed the isoelectric points of heteromeric Cx26/Cx32 channels. For heteromeric channels, Cx26 and Cx32 were found in overlapping, pH-focused fractions, indicating quaternary structure was retained. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to identify post-translational modifications of Cx26 and Cx32 cytoplasmic domains, including the first reported post-translational modifications of Cx26. Suspected modifications were hydroxylation and/or phosphorylation near the amino terminus of both connexins, gamma-carboxyglutamate residues in the cytoplasmic loop of both connexins, phosphorylation in the carboxyl-terminal domain of Cx32, and palmitoylation at the carboxyl-terminus of Cx32. These modifications contribute to the measured acidic isoelectric points of Cx26 and Cx32, whereas their low molecular masses would not appreciably change connexin SDS-PAGE mobility. Most of these modifications have not previously been identified for connexins and may be instrumental in guiding and understanding novel aspects of channel trafficking and molecular mechanisms of channel regulation.

Comparative sequencing of the serine-aspartate repeat-encoding region of the clumping factor B gene (clfB) for resolution within clonal groups of Staphylococcus aureus.

Molecular techniques such as spa typing and multilocus sequence typing use DNA sequence data for differentiating Staphylococcus aureus isolates. Although spa typing is capable of detecting both genetic micro- and macrovariation, it has less discriminatory power than the more labor-intensive pulsed-field gel electrophoresis (PFGE) and costly genomic DNA microarray analyses. This limitation hinders strain interrogation for newly emerging clones and outbreak investigations in hospital or community settings where robust clones are endemic. To overcome this constraint, we developed a typing system using DNA sequence analysis of the serine-aspartate (SD) repeat-encoding region within the gene encoding the keratin- and fibrinogen-binding clumping factor B (clfB typing) and tested whether it is capable of discriminating within clonal groups. We analyzed 116 S. aureus strains, and the repeat region was present in all isolates, varying in sequence and in length from 420 to 804 bp. In a sample of 36 well-characterized genetically diverse isolates, clfB typing subdivided identical spa and PFGE clusters which had been discriminated by whole-genome DNA microarray mapping. The combination of spa typing and clfB typing resulted in a discriminatory power (99.5%) substantially higher than that of spa typing alone and closely approached that of the whole-genome microarray (100.0%). clfB typing also successfully resolved genetic differences among isolates differentiated by PFGE that had been collected over short periods of time from single hospitals and that belonged to the most prevalent S. aureus clone in the United States. clfB typing demonstrated in vivo, in vitro, and interpatient transmission stability yet revealed that this locus may be recombinogenic in a primarily clonal population structure. Taken together, these data show that the SD repeat-encoding region of clfB is a highly stable marker of microvariation, that in conjunction with spa typing it may serve as a DNA sequence-based alternative to PFGE for investigating genetically similar strains, and that it is useful for analyzing collections of isolates in both long-term population-based and local epidemiologic studies.

Tetracycline-regulated expression enables purification and functional analysis of recombinant connexin channels from mammalian cells.

Intercellular coupling mediated by gap junction channels composed of connexin protein underlies numerous physiological processes, such as cellular differentiation, tissue synchronization and metabolic homoeostasis. The distinct molecular permeability of junctional channels composed of different connexin isoforms allows cellular control of coupling via regulation of isoform expression. However, the permeability properties of most connexin isoforms have not been well characterized due to the difficulty of manipulating and measuring the diffusible concentrations of cytoplasmic messenger molecules and metabolites, and to a lack of control over channel isoform composition, in vivo. Here we present a method to express and purify active connexin hemichannels of a single isoform or a consistent ratio of two isoforms from cultured cells using the Tet-On inducible expression system and one-step anti-haemagglutinin immunoaffinity purification. The procedure yields 10-20 microg of pure connexin protein from 2.5x10(8) HeLa cells. The purified channels are shown to be useful for in vitro permeability analysis using well established techniques. This method has substantial advantages over existing methods for heterologous connexin expression, such as the ease of co-expression of two isoforms at a constant ratio, consistently high expression levels over many passages, and the ability to study channel properties in situ as well as in purified form. Furthermore, the generic cloning site of the new pBI-GT vector and the commercial availability of anti-haemagglutinin (clone HA-7)-agarose make this affinity tagging and purification procedure easily applicable to other proteins.

Reversible pore block of connexin channels by cyclodextrins.

Cyclodextrins (CDs), a series of hollow cyclic glucosaccharides, can reversibly block molecular permeation through channels formed by connexin-32 and/or connexin-26 reconstituted into liposomes. The character of the block changes as a function of the size of the CD relative to the connexin pore diameter, suggesting that the block occurs via entry of the CD into the pore lumen and occlusion of the permeability pathway. The block occurs only when the CD is applied to the side of the pore that is normally cytoplasmic and not from the side that is normally extracellular. The block is potentiated when organic analytes are sequestered in the hydrophobic interior of the CDs. CDs may be useful as molecular tools with which to explore the structure of the connexin pore and to alter molecular movement through connexin channels.