Temporal and spatial variabilities of atmospheric polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and polycyclic aromatic hydrocarbons (PAHs) in the Canadian Arctic: results from a decade of monitoring.

The Northern Contaminants Program (NCP) baseline monitoring project was established in 1992 to monitor for persistent organic pollutants (POPs) in Arctic air. Under this project, weekly samples of air were collected at four Canadian and two Russian arctic sites, namely Alert, Nunavut; Tagish, Yukon; Little Fox Lake, Yukon; Kinngait, Nunavut; Dunai Island, Russia and Amderma, Russia. Selected POPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides, were analyzed in both the gas and particulate phases. This paper summarizes results obtained from this project in the past 5 years. Temporal trends were developed for atmospheric PCBs and OCs observed at Alert using a digital filtration (DF) technique. It was found that trends developed with 5 years of data (1993-1997) did not differ significantly from those determined with 7 years of data (1993-1999). This implies that with the DF technique, long-term trends can still be developed with less than 10 years of data. An acceleration in decline of OC and PCB air concentrations was noted in 1999 for some compounds, although the reason is unknown. Monitoring efforts must continue to assess the effect of this decline on the long-term trends of POPs in the Canadian Arctic. Occasional high trans-/cis-chlordane ratios and heptachlor air concentrations measured at Alert between 1995 and 1997 suggests sporadic fresh usage of chlordane-based pesticides. However, significant decreasing trends of chlordanes along with their chemical signatures has provided evidence that emission of old soil residues is replacing new usage as an important source to the atmosphere. Measurements of OC air concentrations conducted at Kinngait in 1994-1995 and 2000-2001 indicated faster OC removal at this location than at Alert. This may be attributed to the proximity of Kinngait to temperate regions where both biotic and abiotic degradation rates are faster. The PAH concentrations observed at Alert mimic those at mid-latitudes and are consistent with long-range transport to the Arctic, particularly for the lighter PAHs. A decline in particulate PAH was observed, similar to atmospheric sulphate aerosol and can be attributed to the collapse of industrial activity in the former Soviet Union between 1991 and 1995. Spatial comparisons of OC seasonality at Alert, Tagish, Dunai and Kinngait show elevated air concentrations of some compounds in spring. However, elevated spring concentrations were observed for different compounds at different sites. Potential causes are discussed. Further investigation in the atmospheric flow pattern in spring which is responsible for the transport of POPs into the Arctic is required. OC and PCB air concentrations at Alert were found to be influenced by two climate variation patterns, the North Atlantic Oscillation (NAO) and the Pacific North American (PNA) pattern. Planetary atmospheric patterns must be taken into account in the global prediction and modelling of POPs in the future.

Sticky windows: chemical and biological characteristics of the organic film derived from particulate and gas-phase air contaminants found on an urban impervious surface.

A novel environmentally derived mixture that integrates exposure to atmospherically derived gas- and particle-phase compounds in urban areas-namely, the organic film that develops as a thin layer on urban impervious surfaces-was investigated for its ability to induce gene expression via the aryl hydrocarbon receptor (AhR). The organic film on window glass from 21 sites in downtown Toronto (Ontario, Canada) was found to contain a complex mixture of environmental contaminants typical of urban environments, notably PAHs, n-alkanes, PCBs, organochlorine (OC) pesticides, and polar constituents. Using a stably transfected reporter cell line, we found that the crude extract of organic film induces AhR-dependent gene expression in a dose-dependent fashion. Three subfractions of the crude extract induced significant luciferase expression: nonpolar aromatic > polar aromatic > nonpolar aliphatic. Recombination of the fractions did not lead to recovery of the full activity of the crude extract, which may indicate that some of the compounds lost during fractionation were significant contributors to the induction observed with the crude extract. The interactions between a tonic dose of B[ a]P (10(-7) M) and each of the aromatic fractions were determined to be antagonistic following analysis by the method of isoboles. Our results suggest that organic film makes up a diverse array of compounds active at the AhR and that these compounds may not interact in a strictly additive manner.

Analysis of C(14)-C(17) Polychloro-n-alkanes in Environmental Matrixes by Accelerated Solvent Extraction-High-Resolution Gas Chromatography/Electron Capture Negative Ion High-Resolution Mass Spectrometry.

A method for quantifying medium-chain (C(14)-C(17)) polychloroalkanes (mPCAs) in environmental matrixes by accelerated solvent extraction high-resolution gas chromatography/electron capture negative ion high-resolution mass spectrometry in the selected ion monitoring mode is presented. The formula group abundance profiles of industrial mPCA mixtures, which are used as standards, and of samples are first determined by monitoring [M - Cl](-) ions of specific m/z values corresponding to the molecular formulas present and by correcting the integrated ion signals for the fractional abundance of the specific m/z value monitored and the number of chlorine atoms in the formula group. mPCA concentrations in environmental samples are then determined by comparing the response of a specific m/z peak in the sample to that in the standard. Extraction recoveries of mPCAs from spiked fish and sodium sulfate (in place of sediment) were >79%. Method detection limits were 13 ng/g for fish and 1.4 ng/µL for sediment, while the analytical detection limit was ∼200 pg, at a signal-to-noise ratio of 4:1. By this method, mPCAs were detected in biota and sediment from the mouth of the Detroit River (MI) and ranged from 70 to 900 ng/g. The simultaneous quantitation of C(10)-C(13) (sPCAs) and C(14)-C(17) PCAs, based on monitoring two specific m/z peaks, one characteristic of sPCAs and the other of mPCAs, is also demonstrated.

Effect of pterygium excision on induced corneal topographic abnormalities.

PURPOSE: To determine the effect of successful pterygium surgery on astigmatism and other corneal topographic indices. METHODS: Preoperative and postoperative refraction and corneal-topography analysis were performed on 16 consecutive eyes of 12 patients who underwent successful pterygium surgery, with statistical comparison of the pre- and postoperative visual acuity, refractive astigmatism, topographic astigmatism, Surface-Regularity Index, and Surface-Asymmetry Index. RESULTS: Successful pterygium surgery caused statistically significant improvements in visual acuity, refractive and topographic astigmatism, the Surface-Regularity Index, and the surface asymmetry index. CONCLUSION: Corneal-topography analysis is an important component of the evaluation of patients with pterygium, revealing significant abnormalities that are improved by successful removal of the pterygium.

Diagnosis and successful medical treatment of Acanthamoeba keratitis.

OBJECTIVE: To identify the methods that result in timely diagnosis and effective treatment of Acanthamoeba keratitis. METHODS: We retrospectively reviewed the medical records of 12 consecutive patients whom we treated for culture-proved Acanthamoeba keratitis in 14 eyes. RESULTS: Contact lenses were worn in 13 of 14 affected eyes and substandard methods were often used to care for them. The diagnosis was established in all patients by laboratory analysis of corneal scrapings; corneal biopsies were not required. Acanthamoeba organisms were identified on smears from 12 of 14 eyes with use of standard, nonfluorescent stains and recovered in culture from all patients by inoculating scrapings on nonnutrient agar overlaid with Escherichia coli. Eleven of 14 eyes were medically cured with a combination of antiamebic drugs, most commonly propamidine isethionate, neomycin sulfate, and clotrimazole. Topical corticosteroids were used in only one patient. Two of the three eyes that required therapeutic keratoplasty were not treated before surgery according to our usual protocol; the third required keratoplasty for treatment of a severe bacterial superinfection. Twelve of 14 eyes recovered 20/50 or better visual acuity. Bacterial superinfections were a serious problem, with a total of six superinfections occurring in three treated eyes. CONCLUSION: With timely diagnosis and medical treatment with a combination of antiamebic drugs and avoidance of topical corticosteroids, most cases of Acanthamoeba keratitis can be cured, with an excellent prognosis for visual recovery.

Teaching ophthalmology to primary care physicians. The Association of University Professors of Ophthalmology Education Committee.

The evolution of our health care system toward managed care has placed primary care "gatekeeper" physicians in a position where they must examine and treat patients with diseases that are ordinarily treated by medical and surgical subspecialists. Many of these physicians may be poorly prepared to accept this new responsibility. The Association of University Professors of Ophthalmology (AUPO) has published a Policy Statement on Medical Student Education that suggests the minimum level of competence expected of general physicians when dealing with ophthalmologic problems. A recent survey of directors of residency programs in family practice, internal medicine, and pediatrics revealed that the training of primary care physicians (as opposed to academicians or subspecialists) has become a nearly universal programmatic goal. Most program directs believe that less than half of their residents meet the AUPO standard at the completion of medical school, and a significant minority do not meet the AUPO standard at the completion of their residency. An overwhelming majority of program directors believe that additional training in ophthalmology and other subspecialties should be incorporated into the training programs of primary care physicians. Ophthalmologists and other subspecialists should develop programs at the medical student level directed toward the education of primary care physicians, and should participate in the training of primary care physicians, as well as their own subspecialty residents. In the future, the primary care physician must be considered part of the "eye care team." Enhancing the ophthalmologic education of primary care physicians is in the best interest of quality patient care.

Drainage tube implants in the treatment of glaucoma following penetrating keratoplasty.

A retrospective review was undertaken to compare outcomes in 26 eyes that underwent penetrating keratoplasty (PKP) and drainage tube surgery (Molteno double-plate implant or Schocket procedure). Drainage tube surgery was performed either before PKP (10 eyes), after PKP (7 eyes), or at the same time as PKP (9 eyes). Mean follow up was 22 months. The average preoperative intraocular pressure (IOP) for all of the eyes was 31 mm Hg; 96% of them achieved a final IOP of less than 18 mm Hg (average, 14 mm Hg on a mean of 0.8 medications). Graft failure occurred in 11/26 (42%). Eight of these eyes were regrafted, and six of these eight have remained clear at a mean follow up of 22 months after regrafting. The overall PKP success rate, including the eyes that underwent repeat PKP, was 81%. Visual acuity remained stable or improved in 70% of the eyes.

Intraepithelial sebaceous carcinoma of the conjunctiva and skin of the eyelid.

The authors report a 65-year-old woman with a 10-year history of conjunctivitis and progressive loss of lashes due to widespread intraepithelial sebaceous carcinoma of the conjunctiva and skin of the eyelid. After surgery, serial sections of the entire conjunctiva and eyelids showed a single focus of invasive carcinoma in the bulbar conjunctiva, which probably arose from the epithelium. The absence of cilia on the affected lower lid was associated with neoplastic obliteration of the cilial orifices and low-grade, smoldering lipogranulomatous inflammation. This type of tumor-related alopecia is likely to masquerade as blepharitis because there is no identifiable tumefaction or clinical evidence of recurrent chalazia to suggest an underlying sebaceous carcinoma. The 10-year history of "conjunctivitis" before diagnosis indicates that intraepithelial sebaceous carcinoma may have a prolonged clinical course.

Indications for and results of intraocular lens explantation.

We reviewed the medical records of 97 patients who had 101 consecutive intraocular lens (IOL) explantation procedures, with or without exchange, at the University of Florida Eye Center from January 1, 1983, to December 31, 1987. The majority of the removed IOLs were anterior chamber styles (53.9%), followed by iris-fixated lenses (33.7%). The most common indications for surgery included pseudophakic bullous keratopathy (PBK)--69%, uveitis-glaucoma-hyphema (UGH) syndrome--9%, and IOL instability--7%. The best visual outcome was seen in patients with IOL instability; 50% achieved 20/40 or better visual acuity. Forty one percent of patients with PBK, who had IOL explantation/exchange combined with penetrating keratoplasty, achieved 20/40 or better visual acuity. The poorest visual outcome was seen in patients with the UGH syndrome; 83% had a final acuity of 20/200 or worse. However, these patients achieved resolution of their pain and inflammation and better control of their intraocular pressure as a result of the surgery. Complications leading to IOL explantation tended to occur months to years after the original surgery in patients with closed-loop, semi-flexible anterior chamber lenses and iris-fixated lenses. Posterior chamber lenses were most often removed because of complications unrelated to the implant.

Immunophenotypic characterization of an unusual T-cell lymphoma presenting as anterior uveitis. A clinicopathologic case report.

A 54-year-old woman presented with a unilateral, anterior uveitis that progressed to hypopyon over 4 months despite treatment with steroids. One hundred percent of the cells collected from aspirates of the anterior chamber of the affected eye were morphologically large granular lymphocytes. The aspirated cells were demonstrated by flow cytometry to be a uniform population of T lymphocytes with a diploid genome and an S fraction of 2.3%. On further investigation, the patient was found to have an extensive abdominal malignant lymphoma with the same immunophenotype but different morphologic features than the anterior chamber lymphoid infiltrate. In contrast to the cells in the anterior chamber, the abdominal tumor was highly aggressive as indicated by the cellular morphologic features and the S fraction of 43%. DNA hybridization studies of the abdominal lymphoma demonstrated a T beta 2 T-cell receptor gene rearrangement. The use of these modern diagnostic methods should facilitate the diagnosis of intraocular lymphomas and may have important therapeutic and prognostic implications in the future.

Corneal amyloidosis associated with keratoconus.

Nodular, gray-white, central corneal opacities which extended from the subepithelial zone through the anterior four fifths of the stroma developed in a 50-year-old man with a longstanding history of hard contact lens wear for keratoconus. Results of histopathologic analysis of the corneal button obtained at the time of penetrating keratoplasty disclosed that the opacities were composed of amyloid. Corneal amyloidosis is rarely found in association with keratoconus. Although there were some similarities in the pattern of amyloid deposition to that seen in primary familial amyloidosis of the cornea, the authors believe that their patient is more likely to have had a secondary amyloidosis. Corneal amyloidosis should be considered in keratoconus patients with development of unusual forms of central corneal opacification.

Serious corneal complications of glaucoma filtering surgery with postoperative 5-fluorouracil.

We studied four patients who, having received postoperative 5-fluorouracil after glaucoma filtering operations, developed serious corneal complications. All four patients had preexisting corneal abnormalities including keratoconjunctivitis sicca, exposure keratopathy, and bullous keratopathy. All of the patients developed epithelial defects in the postoperative period. The complications included bacterial corneal ulceration (two patients), sterile corneal ulceration and corneal perforation (one patient), and a keratinized corneal plaque with underlying sterile stromal infiltrate (one patient). The use of 5-fluorouracil, which is an antimetabolite with considerable corneal epithelial toxicity, after glaucoma filtering surgery frequently causes corneal epithelial defects that may lead to secondary complications. Patients receiving this drug should have their corneal status closely monitored. In patients with corneal epithelial disease, 5-fluorouracil should be used with caution.

The effect of enzymatic contact lens cleaning on adherence of Pseudomonas aeruginosa to soft contact lenses.

Previous studies have demonstrated that Pseudomonas aeruginosa adheres more readily to soft contact lenses with a mucin coating than to unworn contact lenses. The mucin coatings that develop on soft contact lenses may, therefore, play a significant role in the pathogenesis of contact lens-associated Pseudomonas corneal ulceration. We tested the ability of a variety of enzymatic contact lens cleaners and other enzyme solutions to decrease the adherence of Pseudomonas to mucin-coated soft contact lenses. Of the commercially available solutions that were tested, cleaning with Optizyme and Extenzyme significantly reduced the adherence of Pseudomonas to the lenses, whereas cleaning with the Softmate Weekly Cleaning System had no effect. Optizyme and Extenzyme were as effective as a 10% solution of acetylcysteine and more effective than a 0.25% trypsin solution. Neuraminidase at pH 5 was the most effective solution at reducing the adherence of Pseudomonas to the lenses, supporting the finding that sialic acid is a specific receptor for Pseudomonas aeruginosa. Soft contact lenses should be cleaned frequently with an effective enzymatic cleaner to reduce the likelihood of Pseudomonas adhering to the lens and thereby reduce the incidence of Pseudomonas corneal ulceration in soft contact lens wearers.

Chromobacterium violaceum infection of the eye. A report of two cases.

We report what we believe to be the first two known cases of Chromobacterium violaceum infection of the eye. One patient had conjunctivitis as the initial manifestation of an ultimately fatal infection. In the second patient, who suffered from chronic granulomatous disease of childhood, orbital cellulitis developed as part of a disseminated C violaceum infection from which he subsequently recovered. Infections caused by C violaceum may involve the eye and orbit. These infections are frequently fatal, but early recognition and aggressive treatment may result in a higher cure rate.

Variables in McCarey-Kaufman corneal storage. Their effect on corneal graft success.

The results of 297 penetrating keratoplasties performed over a four-year period were reviewed retrospectively and correlated with eyebank data to determine the effect of the following corneal storage variables on corneal graft clarity: (1) donor age; (2) death-to-preservation interval; (3) death-to-surgery interval; and (4) eyebank grading of donor corneal tissue. The death-to-preservation interval (including a group of corneas preserved 12-19 hours after death) and death-to-surgery interval up to four days had no effect on corneal graft success. Transplants performed with corneas from younger donors had a higher likelihood of success than grafts from older donors (less than 35 years vs greater than 35 years, P less than 0.01; less than 50 years vs greater than 50 years, P less than 0.005). Transplants using tissue rated excellent or good by the eyebank were more successful than those using tissue rated fair (P less than 0.005). In both instances, these results were most apparent in patients believed to have a good prognosis for graft success. Thirteen cases (4.3%) of primary donor failure were identified. None of the corneal storage variables studied could be correlated with primary donor failure.

Histopathology of meibomian gland dysfunction.

We conducted a histopathologic study of he meibomian glands of seven patients (all men, ranging in age from 58 to 83 years) who had severe or moderately severe meibomian dysfunction and who were undergoing ectropion or entropion repair. Abnormal features included signs of obstruction and dilatation of ducts, enlargement of acini with cystic degeneration and squamous metaplasia, foreign-body reaction and granuloma formation, a mild increase in inflammatory cells, and abnormal keratinization. Demodex organisms were found in both acini and ducts of one patient. These findings were similar to those reported in other entities involving meibomian duct obstruction, probably related to abnormalities of keratinization, plays an important role in the pathogenesis of meibomian gland dysfunction.

Hybridoma antibodies to insoluble antigens of the corneal epithelium.

Human corneal epithelial water insoluble proteins were used to immunize mice. Immune splenocytes were fused with Sp 2/0-Ag14 mouse myeloma cells by 40% PEG. Hybridoma antibodies obtained by somatic cell fusion were tested by radioimmunoassay. Supernatants from antibody positive hybrid colonies were used in immunofluorescence and crossreaction assays to locate and characterize corneal epithelial antigens. At least three distinct epithelial cell antigens were detected, one of which cross-reacts with rabbit corneal epithelial cells.