Urine homogentisic acid and tyrosine: simultaneous analysis by liquid chromatography tandem mass spectrometry.

Alkaptonuria (AKU) is a rare debilitating autosomal recessive disorder of tyrosine metabolism. Deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid (HGA) which although excreted in gram quantities in the urine, is deposited as an ochronotic pigment in connective tissues, especially cartilage. Ochronosis leads to a severe, early-onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, Nitisinone, an inhibitor of the enzyme 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of HGA, resulting in accumulation of the upstream pre-cursor, tyrosine. Using reverse phase LC-MS/MS, a method has been developed to simultaneously quantify urinary HGA and tyrosine. Using matrix-matched calibration standards, two product ion transitions were identified for each compound and their appropriate isotopically labelled internal standards. Validation was performed across the AKU and post-treatment concentrations expected. Intrabatch accuracy for acidified urine was 96-109% for tyrosine and 94-107% for HGA; interbatch accuracy (n=20 across ten assays) was 95-110% for tyrosine and 91-109% for HGA. Precision, both intra- and interbatch was <10% for tyrosine and <5% for HGA. Matrix effects observed with acidified urine (12% decrease, CV 5.6%) were normalised by the internal standard. Tyrosine and HGA were proved stable under various storage conditions and no carryover, was observed. Overall the method developed and validated shows good precision, accuracy and linearity appropriate for the monitoring of patients with AKU, pre and post-nitisinone therapy.

Anesthesia for intraocular surgery.

Surgeons must decide on the type of anesthesia to use when performing cataract surgery. These "viewpoints" articles provide a well-balanced discussion offering the pros and cons of both topical anesthesia and retrobulbar/peribulbar injection. Dr. Dutton gives an overview of both techniques, focusing on relevant orbital anatomy. Drs. Hassan, Edelhauser and Kim, review the various types of topical anesthesia currently in use, and Drs. Spriggs and Broocker examine retrobulbar and peribulbar injections. Both techniques are associated with advantages and risks, so each surgeon must decide which technique is best suited for his or her own practice.

Bovine pericardium as a wrapping for orbital implants.

PURPOSE: We report the use of bovine pericardium as an alternative wrapping for porous orbital implants after enucleation. METHODS: We retrospectively reviewed the records of all patients who received a bovine pericardium-wrapped orbital implant after enucleation by the authors between August 1, 1996, and December 1, 1999. RESULTS: Eighty patients underwent placement of bovine pericardium-wrapped orbital implants. The average age at the time of implantation was 49.3 years (range, 5 years to 83 years). The mean follow-up interval was 11.8 months (range, 2 to 41 months). There were no intraoperative complications. No patient had secondary systemic infection or showed evidence of rejection. There was no clinical evidence to suggest that vascularization of the porous implant was unusually delayed, and there were no complications after secondary drilling and placement of a coupling post. Four (5%) of 80 patients had complications requiring removal of the spherical implant. All 4 patients had hydroxyapatite implants. Two patients had significant exposure requiring removal of the implant at 2 months after surgery; 1 patient had a chronic fistulous tract with secondary infection 3 years after surgery: and 1 patient had chronic orbital pain requiring removal of the implant at 1 year after surgery. CONCLUSIONS: The incidence of implant exposure was less than 4%. This compares favorably to the incidence of exposure of 9% to 21% reported in recent literature. Other complications were few and of minimal clinical significance. The authors conclude that bovine pericardium is a viable option to sclera as a wrapping for porous orbital implants.

Multiple recurrences in malignant peripheral nerve sheath tumor of the orbit: a case report and a review of the literature.

PURPOSE: To report the onset of malignant peripheral nerve sheath tumor of the orbit 8 years after irradiation in a patient with neurofibromatosis type-1. METHODS: Case report of a young man with neurofibromatosis type-1 who received irradiation for presumed bilateral optic nerve and chiasmal gliomas and in whom a malignant peripheral nerve sheath tumor later developed. Exenteration with extirpation of the entire contents of the orbit was performed 6 times. RESULTS: Complete recurrence of the tumor occurred after each surgical procedure until the patient died of malignancy. CONCLUSIONS: Our case underscores the risk of irradiation, especially in children with neurofibromatosis type-1, and emphasizes that radiotherapy should never be given as an empirical therapy. The authors believe that irradiation and neurofibromatosis type-1 may, in combination, pose a significant risk for the development of malignancies. Clear-cut indications and a precise tissue diagnosis are desirable before the initiation of radiotherapy, particularly in the pediatric population. We recommend that if irradiation is necessary in persons with neurofibromatosis type-1, regular follow-up is imperative. In view of the hostile nature of malignant peripheral nerve sheath tumor, early aggressive treatment appears to be the only viable alternative at present.

Localized conjunctival argyrosis: a late sequela of strabismus surgery.

We describe a case of focal argyrosis of the conjunctiva clinically simulating a melanoma. An 82-year-old woman was referred for an asymptomatic pigmented conjunctival lesion. Her only significant past ocular history was strabismus surgery 76 years earlier. Biopsy of the conjunctiva and lateral rectus muscle revealed the discoloration was pigment granules. Energy-dispersive x-ray microanalysis revealed the pigmentation to be silver deposits. The patient had strabismus surgery probably using a silver clip. Argyrosis should be considered in the differential diagnosis of focal pigmented conjunctival lesions.

Orbital Ewing's sarcoma of the orbit.

PURPOSE: Ewing's tumor is a primary tumor of bone in childhood that only rarely involves the orbit. Most such cases are metastatic from distant sites. This tumor may be confused with other small round cell malignancies of childhood, and immunohistochemical studies are essential in making the diagnosis. METHODS: We present two cases of Ewing's tumor of the orbit. One was in a 22-year-old boy with an occult primary tumor in the frontal bone that became symptomatic after forehead trauma. The other example was in a 7-year-old boy with a known Ewing's primary of the clavicle. The clinical manifestations and diagnostic criteria are discussed. RESULTS: In most cases with orbital involvement, ophthalmic symptoms consist of proptosis, pain, and occasionally visual loss and motility restriction. The diagnosis is typically unsuspected before histologic evaluation. Electron microscopic and immunohistochemical analyses are essential in making the diagnosis and are necessary for all such small round cell tumors. CONCLUSIONS: Ewing's sarcoma is a rare orbital tumor of bone mainly affecting children. Local treatment relying on surgical extirpation and radiotherapy alone has proven inadequate, with 5-year survival rates of <10%. The addition of chemotherapy has improved survival rates significantly to approximately 50%.

Anterior tarsal V-wedge resection for cicatricial entropion.

PURPOSE: To determine the effectiveness of using a radiofrequency instrument to resect a V-shaped tarsal wedge for the correction of cicatricial upper eyelid entropion. METHODS: Prospective evaluation of 16 upper eyelids of 11 consecutive patients. RESULTS: The operation was successful in all 16 eyelids, with excellent cosmetic and functional outcomes. CONCLUSIONS: Tarsal V-wedge resection is an effective alternative to other complicated techniques in the management of upper eyelid cicatricial entropion.

Direct internal eyelash bulb extirpation for trichiasis.

PURPOSE: To evaluate the success of internal eyelash bulb extirpation in the management of trichiasis. METHODS: The procedure was performed on 26 consecutive eyelids. RESULTS: Our technique was successful in all cases, with no recurrence of signs or symptoms. CONCLUSIONS: Internal eyelash bulb extirpation is a safe and effective technique to remove trichiatic lashes, while avoiding injury to the conjunctiva.

A comparative study of bovine pericardium (periguard) and homologous sclera as lower eyelid spacer graft analogs in New Zealand white rabbits.

PURPOSE: To compare bovine pericardium (Periguard; Bio-Vascular, Inc., St. Paul, MN, U.S.A.) and homologous sclera as spacer graft analogs in a rabbit model. METHODS: A nonrandomized experimental animal study was conducted. Elliptical subconjunctival implants were placed in one lower eyelid each of 10 rabbits. Five rabbits received homologous sclera implants, and five received bovine pericardium implants. The rabbits were killed 7 weeks later, and the lower eyelids were examined clinically and histopathologically. RESULTS: Rabbit eyelids implanted with Periguard had a more marked inflammatory reaction and more significant collagen lamellar disruption than eyelids implanted with homologous sclera, although clinically they appeared quite similar. CONCLUSIONS: Although bovine pericardium elicited a more intense inflammatory response at the histopathologic level, both implants were similarly tolerated at the clinical level. These findings are consistent with animal and human investigations of bovine pericardium in other parts of the body, and warrant further studies into its potential use in the human eyelid.

The influence of hyperbaric oxygen therapy and irradiation on hydroxyapatite ocular implant exposure and fibrovascular ingrowth in New Zealand white rabbits.

PURPOSE: Lack of adequate fibrovascular ingrowth has been implicated as a cause of exposure of hydroxyapatite (HA) implants in anophthalmic sockets. We investigated the vasculopathic effects of external beam irradiation, and the fibrovascular-enhancement effects of hyperbaric oxygen (HBO), on HA implant exposure and fibrovascular ingrowth in a rabbit model. METHODS: Eighteen rabbits underwent enucleation with implantation of a 12-mm HA sphere. Six rabbits received 20 Gy of external beam orbital irradiation prior to enucleation. Three irradiated and 6 nonirradiated rabbits received postoperative HBO. Three weeks postoperatively, all rabbits were evaluated clinically for evidence of implant exposure. Implants were then removed, and histopathologic analysis of fibrovascular ingrowth was performed. RESULTS: The amount of vascularization as measured by the depth of ingrowth was greater for nonirradiated (89% ingrowth) than for irradiated (71% ingrowth) animals. HA implant exposure occurred in 1 of 12 (8%) of the nonirradiated, and 4 of 6 (67%) of the irradiated rabbit orbits. HBO did not protect irradiated rabbits from exposure, but did enhance fibrovascular ingrowth in nonirradiated rabbits (100% ingrowth vs. 77% ingrowth). CONCLUSION: Impaired orbital vascularization from prior irradiation appears to retard fibrovascular ingrowth into HA implants, and is associated with an increased incidence of exposure. While HBO did not diminish the likelihood of exposure in irradiated sockets, HA fibrovascular ingrowth in normal orbits appeared to increase with HBO. This may have beneficial clinical application in cases of exposure in nonirradiated orbits.

Bovine pericardium versus homologous sclera as wrapping materials for hydroxyapatite ocular implants: an animal study.

PURPOSE: We compared bovine pericardium and homologous sclera as wrapping materials for hydroxyapatite (HA) ocular implants in enucleated New Zealand white rabbits. METHODS: Eighteen rabbits were unilaterally enucleated and the sockets implanted with 10-mm HA spherical implants. Six implants were wrapped with homologous sclera, 6 with bovine pericardium, and 6 were not wrapped. The rabbits were killed 7 weeks later and the sockets were examined clinically for inflammation and implant exposure. Exenterated specimens were assessed histopathologically for inflammation and vascularization. RESULTS: No clinical evidence of implant exposure or extrusion was detected in rabbits receiving sclera or bovine pericardium wrapped implants. Histopathologically, the bovine pericardium displayed more inflammation in its outer portion, as well as more disruption of its lamellar arrangement than did the sclera. Fibrovascular in-growth was complete in all wrapped implants. CONCLUSION: Bovine pericardium behaves similar clinically to homologous sclera as a wrapping material for spherical HA ocular implants in a rabbit model, and may represent a reasonable alternative to sclera in such procedures in humans.

Hard palate mucosal grafts in the treatment of the contracted socket.

PURPOSE: The treatment of the traumatic contracted anophthalmic socket is challenging. The ability to wear an ocular prosthesis may require multiple operations to replace orbital volume, mucosa, or both. Hard palate mucosal grafts are a logical choice to augment mucosa and volume in the reconstruction of a contracted socket. METHODS: Ten patients with severely contracted sockets underwent socket reconstruction using hard palate mucosal grafts. The mucosal surface lining the contracted sockets was undermined and recessed toward the lid margins. Hard palate mucosal grafts that were harvested freehand and by using a radiofrequency instrument were placed in the socket fundus and sutured to the recessed mucosal edges. Forniceal sutures were placed full thickness through the lids, and custom conformers were placed in the sockets. In six patients, fixation sutures were passed through the conformer, fornices, and full thickness through the lid. In four patients, temporary tarsorrhaphies were placed for a minimum of 4 weeks postoperatively. RESULTS: Postoperatively, 8 of the 10 patients were able to wear an ocular prosthesis comfortably. Cosmesis was acceptable. Two patients had recurrent socket contracture and were unable to wear a prosthesis. CONCLUSIONS: Hard palate mucosal grafts are a useful option in the surgical rehabilitation of contracted sockets. A mucosal surface, resistance to contracture, ease of harvesting, and ability for additional harvesting are advantages over other graft materials.

Decrease in intraocular pressure after orbital decompression for thyroid orbitopathy.

BACKGROUND: The effect of thyroid orbitopathy on intraocular pressure (IOP) remains controversial. We carried out a study to determine the effect of orbital decompression surgery on the IOP in patients with advanced thyroid orbitopathy. METHODS: The records of 12 consecutive patients (22 eyes) who underwent decompression surgery for severe thyroid orbitopathy between 1985 and 1996 were reviewed. All patients were maintained on essentially the same medications before and after surgery. The IOP readings, obtained by means of applanation tonometry in primary gaze, from the pre- and postoperative visits were recorded, and the net change was calculated. RESULTS: The mean preoperative and postoperative IOP values were 19.8 mm Hg and 16.8 mm Hg respectively, a significant difference (p = 0.008). Seven of eight eyes with an IOP of 21 mm Hg or greater preoperatively had a postoperative IOP less than 21 mm Hg; these eyes showed a mean decrease in IOP of 5.6 mm Hg. The degree of preoperative IOP elevation was found to be a strong predictor of the amount of IOP lowering after surgery (p = 0.014). INTERPRETATION: Our results support the concept that orbital congestion associated with thyroid orbitopathy produces an increase in IOP by elevation of episcleral venous pressure (EVP) and that orbital decompression may reduce the IOP by decreasing EVP. Decompression surgery may obviate the need for more aggressive management of glaucoma in patients with severe thyroid orbitopathy.

Sebaceous gland carcinoma: a subtle second malignancy following radiation therapy in patients with bilateral retinoblastoma.

BACKGROUND: Second primary malignancies are common after bilateral retinoblastoma; their estimated incidence has been as high as 51% 50 years after diagnosis. Fifteen patients who developed sebaceous gland carcinoma after radiation therapy have been reported in the literature, five of whom were treated for bilateral retinoblastoma. METHODS: The authors conducted a retrospective chart review of patients treated for bilateral retinoblastoma at Duke University Medical Center who later developed sebaceous gland carcinoma. RESULTS: This article reports two patients who developed sebaceous gland carcinoma after radiation therapy for bilateral retinoblastoma. CONCLUSIONS: Delay in diagnosis is often associated with sebaceous gland carcinoma. Because high mortality is observed with metastatic disease, the recognition of this association is important for anyone who follows patients with a history of bilateral retinoblastoma or prior cranial radiation therapy.

Changes in astigmatism after ptosis surgery measured by corneal topography.

A computerized topographic analysis system (EyeSys [EyeSys Technologies, Houston, TX, U.S.A.]) was used to evaluate corneal astigmatic changes (central corneal power and astigmatic axis) after blepharoptosis surgery on 29 eyelids (22 patients). Fifteen nonoperated eyelids of study patients undergoing unilateral ptosis repair were used as controls. All patients were evaluated preoperatively and again 6 weeks after surgery. Fifteen operated eyelids and five controls were also examined 12 months after surgery to evaluate the stability of these measurements. In 72.4% of operated eyes, corneal topography demonstrated increased with-the-rule astigmatism 6 weeks after surgery, 13.8% of surgical eyes showed increasing against-the-rule astigmatism, and in 13.8%, no change was noted from preoperative measurements. None of the 15 control eyes demonstrated any change in corneal astigmatic axis or significant change in central corneal power. By 12 months after surgery, all of the operated eyes showed a regression toward the amount and pattern of preoperative astigmatism. Only two of 15 eyes maintained a difference of > 0.3 D of central corneal power greater than their preoperative measurement at 1 year. These data suggest that corneal topography may be altered by changes in eyelid position, although the changes appear to be temporary in most patients.

Rate of vascularization of coralline hydroxyapatite spherical implants pretreated with saline/gentamicin, rTGF-beta 2, and autogenous plasma.

Several authors have reported significant exposure rates using the hydroxyapatite orbital implant in the treatment of the anophthalmic socket. Histologic studies by ourselves and others have suggested that lack of fibrovascular ingrowth into the implants may contribute to conjunctival breakdown and exposure. Recently, much attention has been given to angiogenic factors, such as rTGF-beta 2 and those found in plasma, in accelerating wound healing and fibrovascular ingrowth. This pilot study compares the rate of vascularization of hydroxyapatite orbital implants pretreated with plasma, rTGF-beta 2, and a saline/gentamicin solution with that in untreated controls ina population of New Zealand albino rabbits. Hydroxyapatite orbital spheres were implanted subcutaneously and in enucleated orbits. Untreated implants were used as a control. Implants pretreated with plasma, rTGF-beta 2, and a saline/gentamicin solution were removed and examined histologically at weekly intervals for the first 3 weeks after implantation. Histologic studies demonstrated that the rate of vascularization significantly increased between 2 and 3 weeks postoperatively in all study groups. Pretreating the implants with rTGF-beta 2 in phosphate buffered solution (PBS) or autogenous plasma did not significantly increase the rate of vascularization in comparison with controls at weeks 1 and 2. However, pretreating the implants with a saline/gentamicin solution or PBS alone was associated with an increased rate of vascularization at weeks 2 and 3. No statistically significant difference in vascularization was noted between the subcutaneous and orbital implants at any week. Hydroxyapatite implants pretreated with saline/gentamicin or phosphate buffered solutions underwent more rapid vascularization at weeks 2 and 3 in comparison with controls. Additionally, all groups were noted to have a more rapid rate of ingrowth between weeks 2 and 3 than between weeks 1 and 2. Plasma and rTGF-beta 2 (at the dose used) did not significantly alter the rate of vascularization of hydroxyapatite implants during the first 2 to 3 weeks. The significance of these findings is discussed.

Double choroidal malignant melanoma in an eye with apparent clinical regression.

Multicentric melanomas in the same eye are rare, with few cases substantiated by histology and serial sectioning. We report a patient with two documented choroidal malignant melanomas in one eye. The initial tumor spontaneously decreased in size for over 2 years before a second tumor appeared in a noncontiguous location in the same eye. After enucleation, serial sections showed that the two lesions were independent choroidal melanomas. We review the literature regarding multiple, independent intraocular choroidal malignant melanomas.

Age-related changes in type-I collagen synthesis in human eyelid skin.

PURPOSE: This study was to determine whether age-related decrements in type I collagen synthesis occur in human eyelid skin. METHODS: Using an antibody to procollagen I, we investigated collagen synthetic activity in skin removed for cosmetic purposes from 10 white patients between the ages of 4 and 77 years. Eleven masked referees graded the immunostaining on a scale of 1 (most intense) to 10 (least intense). RESULTS: The multiple range test for rank by group demonstrated more intense staining in younger patients compared with older patients. An average correlation coefficient of 0.8432 (p < 0.05) existed between each of the referee's rankings. CONCLUSION: Type I collagen synthesis diminishes with age in eyelid skin.