INFUSION PORT SITE TUMOR SEEDING AFTER PARS PLANA VITRECTOMY-ASSISTED BIOPSY OF CHOROIDAL MELANOMA

PURPOSE

To report a rare case of infusion port site tumor seeding of choroidal melanoma after pars plana vitrectomy-assisted biopsy and successful treatment with second plaque brachytherapy.

METHODS

Observational case report with clinical data and diagnostic images.

RESULTS

A 55-year-old White woman diagnosed with choroidal melanoma of the left eye was found to have a second intraocular tumor 30 months after plaque brachytherapy and pars plana vitrectomy-assisted tumor biopsy. The second melanoma developed at the 5 o'clock vitrectomy infusion port site. The tumor regressed after plaque brachytherapy, and the patient has not developed systemic metastasis 5 years after diagnosis of intraocular seeding.

CONCLUSION

Intraocular seeding into the infusion port site, although rare, may be encountered after pars plana vitrectomy-assisted biopsy of choroidal melanoma.

Fundus imaging features of congenital rubella retinopathy

PURPOSE

To evaluate the clinical characteristics of congenital rubella retinopathy (CRR) with modern fundus imaging.

METHODS

Single-center case series. Eleven patients (2005-2020) at the Emory Eye Center with known or presumed CRR. Trained image readers reviewed fundus imaging (color fundus photography, widefield pseudocolor imaging, near-infrared reflectance imaging, autofluorescence imaging, and spectral-domain optical coherence tomography) for pre-specified features suggestive of CRR.

RESULTS

Eleven patients with confirmed (63.6%) or presumed (36.3%) CRR were identified. All were female with median (range) age of 53 (35-67) years. Six (54.5%) were born during the 1964-1965 United States rubella epidemic. All had congenital hearing loss. Two (18.2%) had a congenital heart defect. Eleven (50.0%) eyes had salt-and-pepper retinal pigmentary changes. Twenty-two eyes (100.0%) had irregularly distributed regions of speckled hypoautofluorescence. One eye (4.5%) had a presumed macular neovascularization.

CONCLUSION

Modern fundus imaging demonstrates characteristic features of CRR, even when pigmentary changes are not readily apparent on examination. Widefield autofluorescence findings of irregularly distributed speckled hypoautofluorescence are particularly revealing. This series of newly diagnosed adults with CRR may represent the milder end of the phenotypic spectrum of this condition, highlighting imaging findings that may aid in diagnostically challenging cases of CRR.

Development and validation of a questionnaire to assess owner and canine quality-of-life and treatment satisfaction in canine allergic dermatitis

BACKGROUND

Animal and owner quality-of-life (QoL) is pivotal in treatment decisions. Accurate measurement of owner-reported QoL and treatment satisfaction (TS) supports disease burden and treatment benefit evaluation.

OBJECTIVES

Develop and evaluate an owner-completed canine dermatitis QoL and TS questionnaire (CDQoL-TSQ) in allergic dogs.

MATERIALS AND METHODS

The CDQoL-TSQ was drafted following review of existing measures and expert input. Content validity was assessed through interviews with owners of allergic dogs. Psychometric properties of the QoL domains (Canine QoL, Owner QoL) were evaluated. Score interpretation was derived.

RESULTS

Twenty dog owners were interviewed. Item wording was amended following the first 10 interviews. Data from 211 owners were used in the psychometric evaluation. The Canine QoL domain demonstrated strong internal consistency (α = 0.89), test-retest reliability (ICC2,1  = 0.844), moderate convergent validity (r = 0.41) and moderate-high known-groups validity (effect size 0.37-0.64). The Owner QoL domain demonstrated strong internal consistency (α = 0.73), high convergent validity (r = 0.63) and moderate-high known-groups validity (0.43-0.63). Test-retest reliability approached moderate strength (ICC2,1  = 0.490). Group-level interpretation analysis showed minimal important difference of 7.0-13.6 points for dogs and 13.0-13.6 for owners. For individual dogs a change of 6.3 or 12.5 points for dogs, and 12.5 or 18.8 for owners indicates a response.

CONCLUSIONS AND CLINICAL RELEVANCE

The CDQOL-TSQ is a two-part assessment to evaluate QoL and TS in canine allergic dermatitis. The QoL questionnaire demonstrated validity and reliability, and interpretation of scores was derived, making it suitable for use in research and practice. The TS module is suitable for clinical setting use to improve owner-veterinarian communication.

IODINE-125 PLAQUE BRACHYTHERAPY FOR DIFFUSE CHOROIDAL HEMANGIOMA

PURPOSE

To report 6 cases of diffuse choroidal hemangioma in children treated with iodine-125 plaque brachytherapy at a single tertiary care center.

METHODS

Retrospective case series.

RESULTS

Six pediatric patients diagnosed with diffuse choroidal hemangioma were included in the study. Preplaque visual acuity ranged from 20/150 to no light perception. All patients had extensive serous retinal detachment at presentation. An iodine-125 radioactive plaque was placed on the affected eye to administer a dose of 34.2-42.1 Gy to the tumor apex over a median of 4 days. Tumor regression and subretinal fluid resolution were observed in all eyes within 17 months of treatment. Visual acuity improved in two patients. Radiation-induced cataract and subretinal fibrosis were documented in one case, and one patient developed radiation retinopathy. No patients developed neovascular glaucoma within the follow-up time of 12-65 months.

CONCLUSION

Iodine-125 plaque radiotherapy is an effective option for diffuse choroidal hemangioma, although there is a risk for radiation-induced complications.

Unusual conjunctival melanocytic proliferations. Report of five cases and review of the literature

Indeterminate melanocytic proliferations of the conjunctiva have both benign and malignant features that previously made these lesions nearly impossible to categorize in existing classification schemes. With the evolution of immunohistochemistry and molecular genetics, however, subclassifications have emerged that allow for a more tailored diagnosis and management. These conjunctival melanocytic proliferations include deep penetrating nevus, granular cell nevus, and nevoid melanoma. There remains a small subset of conjunctival melanocytic proliferations that defy precise characterization as nevi, primary acquired melanosis, or melanomas despite currently available ancillary diagnostic modalities and remain indeterminate. We highlight these unusual types of nevi and melanomas, with an update on their morphologic, immunohistochemical, and molecular genetic characteristics.

Use of the European Organisation for Research and Treatment of Cancer multiple myeloma module (EORTC QLQ-MY20): a review of the literature 25 years after development

The European Organisation for Research and Treatment of Cancer Quality of Life Multiple Myeloma Questionnaire (EORTC QLQ-MY20) was developed in 1996 to assess health-related quality of life (HRQoL) in patients with multiple myeloma. Since its development new therapies have prolonged survival in patients with myeloma and new combination agents are likely to impact HRQoL outcomes and its measurement.The aim of this review was to explore the use of the QLQ-MY20 and reported methodological issues.An electronic database search was conducted (1996-June 2020) to identify clinical studies/research that used the QLQ-MY20 or assessed its psychometric properties. Data were extracted from full-text publications/conference abstracts and checked by a second rater.The search returned 65 clinical and 9 psychometric validation studies. The QLQ-MY20 was used in interventional (n = 21, 32%) and observational (n = 44, 68%) studies and the publication of QLQ-MY20 data in clinical trials increased over time. Clinical studies commonly included relapsed patients with myeloma patients (n = 15, 68%) and assessed a range of combinations therapies.QLQ-MY20 subscales (disease symptoms [DS], side effects of treatment [SE], future perspectives [FP], body image [BI]) were defined as secondary (n = 12, 55%) or exploratory (n = 7, 32%) trial endpoints, particularly DS (n = 16, 72%) and SE (n = 16, 72%). Validation articles demonstrated that all domains performed well regarding internal consistency reliability (>0.7), test-reset reliability (intraclass correlation coefficient > =0.85), internal and external convergent and discriminant validity. Four articles reported a high percentage of ceiling effects in the BI subscale; all other subscales performed well regarding floor and ceiling effects.The EORTC QLQ-MY20 remains a widely used and psychometrically robust instrument. While no specific problems were identified from the published literature, qualitative interviews are ongoing to ensure new concepts and side effects are included that may arise from patients receiving novel treatments or from longer survival with multiple lines of treatment.

Foreign body giant cell reaction to silicone oil presenting as a salmon-patch conjunctival lesion

Purpose

To describe a case of foreign body giant cell reaction to silicone oil that presented as a salmon-patch conjunctival lesion.

Observations

An elderly female with prior retinal surgery and oil tamponade was referred for a salmon-patch lesion in the conjunctiva. Biopsy revealed multiple vacuolations and foreign body giant cells in the substantia propria, consistent with a foreign body reaction to silicone oil.

Conclusion and importance

Silicone oil can elicit an inflammatory reaction in the conjunctiva that could mimic a neoplasm. Excessive leakage of oil into the subconjunctival space should be avoided to prevent this complication.

Unilateral Xanthocoria and Retinal Vascular Anomalies in a 3-Year-Old Boy: Retinoblastoma or Coats Disease?

The authors describe a challenging case of unilateral retinoblastoma in a patient referred for xanthocoria. A 3-year-old boy was referred for unilateral xanthocoria and disordered retinal vasculature, suggestive of Coats disease. Further investigation revealed diffuse subretinal tumor seeding and areas of calcification, consistent with retinoblastoma. Enucleation was performed and histopathology confirmed exophytic retinoblastoma. This case highlights that xanthocoria, although often encountered in patients with Coats disease, can sometimes be associated with retinoblastoma. As such, retinoblastoma should be considered in the differential diagnosis for children with both leukocoria and xanthocoria. [J Pediatr Ophthalmol Strabismus. 2022;59(X):e32-e34.].

Intraocular Lens and Lens Capsule Spread of Iridociliary Melanoma: Clinical and Histopathologic Features of 2 Cases

Purpose: To describe two patients with intraocular lens (IOL) and lens capsule spread of iridociliary melanoma. Methods: Two pseudophakic patients with iridociliary body melanoma that spread onto the surface of their IOL and remaining lens capsule were included. Their eyes were enucleated and the histopathologic features were evaluated. Results: Case 1 was an 82-year-old woman with diffuse primary iridociliary melanoma affecting the iris, lens capsule, IOL surface, and ciliary body. Case 2 was a 68-year-old female who developed melanoma recurrence in the anterior segment after plaque brachytherapy for iridociliary melanoma. The melanoma in both cases grew as a pigmented membrane onto the surface of the IOL. Conclusions: Intraocular lens and lens capsule spread of iridociliary melanoma can occur primarily or develop secondarily after plaque brachytherapy of a pseudophakic eye. Since the extent of the melanoma may be uncertain and there is a high likelihood of glaucoma, enucleation is a reasonable option.

Cell Phone Selfies: Clinching the Diagnosis of Iris Microhemangiomatosis

Four patients presented with a history of "blood" or a "dark spot" in the eye captured on cell phone photos. These episodes prompted presentation to an ophthalmologist where they all had normal slit lamp exams without a hyphema at initial evaluation. With evidence of a spontaneous hyphema seen on photos, further testing was performed including iris fluorescein angiography which revealed hyperfluorescent iris margin vascular tufts, confirming the diagnosis of iris microhemangiomatosis in each patient. All cases were managed conservatively, and only 1 needed topical antihypertensives. Without these patient-initiated photos, the diagnosis of iris microhemangiomatosis would likely remain elusive as slit lamp exam was normal at the time of initial examination in all 4 cases. Ophthalmologists should be aware of this rare diagnosis in the event a patient comes with a cell phone selfie documenting a spontaneous hyphema, especially when emanating from pupillary border.

Clinical and Histopathological Features of Corneal Primary Acquired Melanosis and Melanoma

Aim

The aim of this study is to describe the clinical and pathologic features of corneal primary acquired melanosis (PAM) and melanoma.

Methods

We describe 3 cases in total: two cases of corneal melanomas and 1 case of corneal PAM. The eyes were processed routinely for histopathological examination. Clinical histories, treatments, and outcomes were reviewed.

Results

Corneal melanomas arose from recurrence of conjunctival melanoma or conjunctival PAM at the limbus. One patient had a recurrence after excision of a limbal melanoma, another had a de novo corneal melanoma, and the last patient had corneal PAM in the setting of conjunctival PAM with atypia. All lesions were excised with adjuvant alcohol debridement and cryotherapy with no recurrence ranging from 1 week to 8 years.

Conclusions

Corneal melanomas arise at the limbus from corneal PAM or conjunctival atypia. They can appear after excisional removal of a conjunctival melanoma. Surgical excision with alcohol debridement and adjuvant cryotherapy is successful.

Secondary ocular malignancies: A review

Secondary ocular malignancies most commonly spread to the choroid. Previously, the prognosis was poor however, with newer treatments including immunotherapy, patient's life expectancy have increased. It is therefore, important that ophthalmologists diagnose this condition in a timely manner and offer treatment to maximize visual potential and refer them on to oncology colleagues in order to optimize their systemic treatment for their primary cancer.

Indoor Surface Chemistry: Developing a Molecular Picture of Reactions on Indoor Interfaces

Chemical reactions on indoor surfaces play an important role in air quality in indoor environments, where humans spend 90% of their time. We focus on the challenges of understanding the complex chemistry that takes place on indoor surfaces and identify crucial steps necessary to gain a molecular-level understanding of environmental indoor surface chemistry: (1) elucidate key surface reaction mechanisms and kinetics important to indoor air chemistry, (2) define a range of relevant and representative surfaces to probe, and (3) define the drivers of surface reactivity, particularly with respect to the surface composition, light, and temperature. Within the drivers of surface composition are the roles of adsorbed/absorbed water associated with indoor surfaces and the prevalence, inhomogeneity, and properties of secondary organic films that can impact surface reactivity. By combining laboratory studies, field measurements, and modeling we can gain insights into the molecular processes necessary to further our understanding of the indoor environment.

Approach to Cataract Surgery in an Ebola Virus Disease Survivor with Prior Ocular Viral Persistence

A 46-year-old patient with previously documented Ebola virus persistence in his ocular fluid, associated with severe panuveitis, developed a visually significant cataract. A multidisciplinary approach was taken to prevent and control infection. Ebola virus persistence was assessed before and during the operation to provide safe, vision-restorative phacoemulsification surgery.

Treatment of presumed Nocardia endophthalmitis and subretinal abscess with serial intravitreal amikacin injections and pars plana vitrectomy

A 64-year-old man with a past medical history of liver transplantation on chronic immunosuppressive therapy presented with gradual worsening of vision over 2 months in his right eye. His recent history of Aspergillus and Nocardia pneumonia with positive bronchoalveolar lavage, in concert with vitritis and subretinal abscess, were concerning for endogenous endophthalmitis. A sputum culture and transbronchial lung biopsy stains grew Nocardia farcinica although aqueous humor sampling was negative. He was treated with four serial amikacin intravitreal injections over the course of 4 weeks. Pars plana vitrectomy for worsening macular traction and subsequent cataract surgery resulted in significant clinical and anatomic improvement of vision to 20/60 and consolidation of the subretinal abscess.

Intravitreous Cutaneous Metastatic Melanoma in the Era of Checkpoint Inhibition: Unmasking and Masquerading

PURPOSE

Cutaneous melanoma metastatic to the vitreous is very rare. This study investigated the clinical findings, treatment, and outcome of patients with metastatic cutaneous melanoma to the vitreous. Most patients received checkpoint inhibition for the treatment of systemic disease, and the significance of this was explored.

DESIGN

Multicenter, retrospective cohort study.

PARTICIPANTS

Fourteen eyes of 11 patients with metastatic cutaneous melanoma to the vitreous.

METHODS

Clinical records, including fundus photography and ultrasound results, were reviewed retrospectively, and relevant data were recorded for each patient eye.

MAIN OUTCOME MEASURES

Clinical features at presentation, ophthalmic and systemic treatments, and outcomes.

RESULTS

The median age at presentation of ophthalmic disease was 66 years (range, 23-88 years), and the median follow-up from diagnosis of ophthalmic disease was 23 months. Ten of 11 patients were treated with immune checkpoint inhibition at some point in the treatment course. The median time from starting immunotherapy to ocular symptoms was 17 months (range, 4.5-38 months). Half of eyes demonstrated amelanotic vitreous debris. Five eyes demonstrated elevated intraocular pressure, and 4 eyes demonstrated a retinal detachment. Six patients showed metastatic disease in the central nervous system. Ophthalmic treatment included external beam radiation (30-40 Gy) in 6 eyes, intravitreous melphalan (10-20 μg) in 4 eyes, enucleation of 1 eye, and local observation while receiving systemic treatment in 2 eyes. Three eyes received intravitreous bevacizumab for neovascularization. The final Snellen visual acuity ranged from 20/20 to no light perception.

CONCLUSIONS

The differential diagnosis of vitreous debris in the context of metastatic cutaneous melanoma includes intravitreal metastasis, and this seems to be particularly apparent during this era of treatment with checkpoint inhibition. External beam radiation, intravitreous melphalan, and systemic checkpoint inhibition can be used in the treatment of ophthalmic disease. Neovascular glaucoma and retinal detachments may occur, and most eyes show poor visual potential. Approximately one quarter of patients demonstrated ocular disease that preceded central nervous system metastasis. Patients with visual symptoms or vitreous debris in the context of metastatic cutaneous melanoma would benefit from evaluation by an ophthalmic oncologist.

Exploring the science, safety, and benefits of air care products: perspectives from the inaugural air care summit

Seventy-one percent of US households purchase air care products. Air care products span a diverse range of forms, including scented aerosol sprays, pump sprays, diffusers, gels, candles, and plug-ins. These products are used to eliminate indoor malodors and to provide pleasant scent experiences. The use of air care products can lead to significant benefits as studies have shown that indoor malodor can cause adverse effects, negatively impacting quality of life, hygiene, and the monetary value of homes and cars, while disproportionately affecting lower income populations. Additionally, studies have also shown that scent can have positive benefits related to mood, stress reduction, and memory enhancement among others. Despite the positive benefits associated with air care products, negative consumer perceptions regarding the safety of air care products can be a barrier to their use. During the inaugural Air Care Summit, held on 18 May 2018 in the Washington, DC, metropolitan area, multidisciplinary experts including industry stakeholders, academics, and scientific and medical experts were invited to share and assess the existing data related to air care products, focusing on ingredient and product safety and the benefits of malodor removal and scent. At the Summit's completion, a panel of independent experts representing the fields of pulmonary medicine, medical and clinical toxicology, pediatric toxicology, basic science toxicology, occupational dermatology and experimental psychology convened to review the data presented, identify potential knowledge gaps, and suggest future research directions to further assess the safety and benefits of air care products.

Evaluation of emissions and exposures at workplaces using desktop 3-dimensional printer

There is a paucity of data on additive manufacturing process emissions and personal exposures in real-world workplaces. Hence, we evaluated atmospheres in four workplaces utilizing desktop "3-dimensional" (3-d) printers [fused filament fabrication (FFF) and sheer] for production, prototyping, or research. Airborne particle diameter and number concentration and total volatile organic compound concentrations were measured using real-time instruments. Airborne particles and volatile organic compounds were collected using time-integrated sampling techniques for off-line analysis. Personal exposures for metals and volatile organic compounds were measured in the breathing zone of operators. All 3-d printers that were monitored released ultrafine and fine particles and organic vapors into workplace air. Particle number-based emission rates (#/min) ranged from 9.4 × 109 to 4.4 × 1011 (n = 9samples) for FFF3-d printers and from 1.9 to 3.8 × 109 (n = 2 samples) for a sheer 3-d printer. The large variability in emission rate values reflected variability from the printers as well as differences in printer design, operating conditions, and feedstock materials among printers. A custom-built ventilated enclosure evaluated at one facility was capable of reducing particle number and total organic chemical concentrations by 99.7% and 53.2%, respectively. Carbonyl compounds were detected in room air; however, none were specifically attributed to the 3-d printing process. Personal exposure to metals (aluminum, iron) and 12 different organic chemicals were all below applicable NIOSH Recommended Exposure Limit values, but results are not reflective of all possible exposure scenarios. More research is needed to understand 3-d printer emissions, exposures, and efficacy of engineering controls in occupational settings.

Scleral Thinning after Transscleral Biopsy for Uveal Melanoma Using Lamellar Scleral Flap

Purpose

The purpose of the study is to describe the clinical history and histopathologic findings of three cases of scleral thinning after lamellar scleral flap, including one case with confirmed extraocular tumor extension.

Methods

The medical records and pathology specimens of three patients with scleral thinning after biopsy and plaque brachytherapy and lamellar scleral flap performed during a transscleral biopsy were reviewed.

Results

The first two patients developed scleral thinning and visible pigmentation, but had tumors that were regressing in size on ultrasound. The two patients were followed by serial observation. The third patient exhibited scleral thinning and evidence of tumor growth on ultrasound, raising the suspicion for extraocular tumor extension. Histopathologic examination of the enucleated eye confirmed extrascleral tumor extension and showed necrotic and intact melanoma with associated pigmented macrophages.

Conclusions

Patients with scleral flaps created for biopsy of uveal melanoma are at risk for scleral thinning and extrascleral extension of tumor recurrence through the flap.

Trends in Radiation Practices for Female Ocular Oncologists in North America: A Collaborative Study of the International Society of Ocular Oncology

Background

The aim of this study was to determine the known radiation exposure, attitudes, and consequent risk modifications among female ocular oncologists in North America who routinely administer radioactive plaque brachytherapy treatment and are members of the International Society of Ocular Oncology.

Methods

Nineteen female ocular oncologists completed an anonymous 17-question radiation exposure survey.

Results

Eleven of the participants chose to routinely wear lead protection during surgery; 8 did not. Fifteen of 19 participants reported using an unloaded "nonactive" template to prepare for plaque implantation. During pregnancy, 11 of 13 participants continued to perform plaque brachytherapy. Eight of these 11 undertook measures to decrease radiation exposure self-reported as lead wear and other. The average reported anxiety regarding fertility was 2.1 (SD, 2.2) on a scale from 1 to 10.

Conclusion

This study corroborates prior literature that surgeons' exposure to radiation during plaque brachytherapy is minimal. Nonetheless, there remains some anxiety regarding exposure risk to women, due to potential effects on fertility and fetal health. We found variability in exposure monitoring, required training, and precautions during pregnancy amongst this group of surgeons. Improved education and clearer pregnancy guidelines may equip female ocular oncologists with optimal knowledge regarding risk of radiation exposure.

Reactive indoor air chemistry and health-A workshop summary

The chemical composition of indoor air changes due to the reactive nature of the indoor environment. Historically, only the stable parent compounds were investigated due to their ease of measurement by conventional methods. Today, however, scientists can better characterize oxidation products (gas and particulate-phase) formed by indoor chemistry. An understanding of occupant exposure can be developed through the investigation of indoor oxidants, the use of derivatization techniques, atmospheric pressure detection, the development of real-time technologies, and improved complex modeling techniques. Moreover, the connection between exposure and health effects is now receiving more attention from the research community. Nevertheless, a need still exists for improved understanding of the possible link between indoor air chemistry and observed acute or chronic health effects and long-term effects such as work-related asthma.

Identification and quantification of carbonyl-containing α-pinene ozonolysis products using O-tert-butylhydroxylamine hydrochloride

The yields of carbonyl-containing reaction products from the ozonolysis of α-pinene have been investigated using concentrations of ozone found in the indoor environment ([O₃] ≤ 100 ppb). An impinger was used to collect gas-phase oxidation products in water, where the derivatization agent O-tert-butylhydroxylamine hydrochloride (TBOX) and gas chromatography-mass spectrometry were used to identify carbonyl-containing species. Seven carbonyl-containing products were observed. The yield of the primary product, pinonaldehyde was measured to be 76 %. Using cyclohexane as a hydroxyl radical (OH) scavenger, the yield of pinonaldehyde decreased to 46 %, indicating the influence secondary OH radicals have on α-pinene ozonolysis products. Furthermore, the use of TBOX, a small molecular weight derivatization agent, allowed for the acquisition of the first mass spectral data of oxopinonaldehyde, a tricarbonyl reaction product of α-pinene ozonolysis. The techniques described herein allow for an effective method for the collection and identification of terpene oxidation products in the indoor environment.

Uveal Melanoma Nuclear BRCA1-Associated Protein-1 Immunoreactivity Is an Indicator of Metastasis

PURPOSE

To examine the BRCA1-associated protein-1 (BAP1) expression of primary uveal melanomas without and with metastasis, and to analyze the correlation between the BAP1 immunoreactivity of primary uveal melanoma and other clinicopathologic features.

DESIGN

Retrospective case series.

PARTICIPANTS

Forty patients with uveal melanoma (mean age, 57.98±14.75 years) were included in this analysis, of whom 20 had no metastatic disease and 20 had metastasis.

METHODS

Medical records and histology slides of patients with primary uveal melanoma treated by enucleation were reviewed. BAP1 expression was evaluated by immunohistochemical staining of formalin-fixed, paraffin-embedded sections. Immunoreactivity in the nucleus and cytoplasm were graded by estimating the percentage of primary tumor cells showing a positive staining of their nucleus or cytoplasm per 1 high-power field 200× (grades 0-3).

MAIN OUTCOME MEASURES

Tumor size, histologic features, nuclear and cytoplasmic BAP1 immunoreactivity grade, and patient outcome, including development of metastasis.

RESULTS

Significantly lower (P = 0.025) nuclear BAP1 immunoreactivity was observed in the metastatic melanoma group. Greater tumor thickness, basal diameter, and more advanced TNM stage were associated with an increased odds ratio of developing metastasis (P < 0.05). In addition, tumors with a higher proportion of cells expressing nuclear BAP1 had decreased odds of developing metastatic disease in a multivariate model (P = 0.042). Metastasis-free survival was significantly longer in patients with uveal melanoma with high nuclear BAP1 stain (P = 0.004).

CONCLUSIONS

Time to metastasis differs in patients with primary uveal melanoma with different grades of nuclear BAP1 immunoreactivity. Nuclear BAP1 stain is the only significant independent predictor of metastatic disease in this study. Our data support the role of BAP1 immunohistochemical staining of primary uveal melanoma to evaluate metastatic risk.

Retinoinvasive Uveal Melanoma: Report of 2 Cases and Review of the Literature

Purpose

To describe the clinical history and histopathologic findings of 2 cases of retinoinvasive uveal melanoma.

Methods

The medical records and pathology specimens of 2 patients with retinoinvasive uveal melanoma were reviewed.

Results

The first patient had an iris/ciliary body melanoma that was treated and the second patient had suspected iridocorneal endothelial syndrome. Both patients developed a blind, painful eye; the first patient's right eye was enucleated and the left eye of the second patient underwent evisceration. Histopathologic examination of the enucleated eye showed a tumor composed of minimally pigmented spindle-shaped cells with fusiform nuclei and prominent nucleoli and round cells with prominent nucleoli. The tumor cells invaded into the retina where they formed perivascular aggregates. Examination of the evisceration specimen showed a proliferation of pigmented tumor cells within the stroma of one iris leaflet. The tumor cells extended onto the ciliary body and vitreous base and invaded the retina. The pathologic diagnosis in both patients was retinoinvasive uveal melanoma.

Conclusions

Careful funduscopic and imaging examination should be performed in eyes with unilateral glaucoma with iris/ciliary body lesions, and enucleation, rather than evisceration, should be performed, as retinoinvasive melanoma is in the differential diagnosis.

Mechanisms of Optic Nerve Invasion in Primary Choroidal Melanoma

Aim

The aim of this study was to assess morphological risk factors associated with optic nerve invasion of choroidal melanoma and to identify possible mechanisms of optic nerve invasion.

Methods

Medical charts and histology slides of patients with primary choroidal melanoma who were treated by enucleation/exenteration and whose pathology showed optic nerve invasion were reviewed.

Results

Twenty-one patients (mean age: 65.67 ± 14.72 years) with primary uveal melanoma arising from the choroid were included in this analysis. A peripapillary location was present in 86% of the cases. Four types of optic nerve invasion were identified: transvitreal invasion (10%); retinal invasion (23%); direct peripapillary invasion (57%); and a combined mechanism (10%). Optic nerve invasion was prelaminar in 67%, laminar in 10%, and retrolaminar in 23% of the cases. Significantly higher largest basal diameter (p = 0.021) and tumor thickness values (p = 0.017) and higher rates of vortex vein (p = 0.022) and retinal invasion (p = 0.007) were observed in the transvitreal/retinal invasion groups when compared to the direct peripapillary invasion group.

Conclusions

A peripapillary tumor location was the most common mechanism of optic nerve invasion of choroidal melanoma. In 43% of the cases, other mechanisms including transvitreal and retinal invasion resulted in optic nerve invasion.

Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents

Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance,we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity.We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (Rt) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na+ transport,without affecting Cl- transport or Na+,K+-pump activity. Rt was unaffected. Na+ transport recovered 18 h after exposure. Concentrations (100-360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro.

Histopathologic grading of anaplasia in retinoblastoma

PURPOSE

To determine whether the degree of tumor anaplasia has prognostic value by evaluating its correlation with high-risk histopathologic features and clinical outcomes in a series of retinoblastoma patients.

DESIGN

Retrospective clinicopathologic study.

METHODS

The clinical and pathologic findings in 266 patients who underwent primary enucleation for retinoblastoma were reviewed. The histologic degree of anaplasia was graded as retinocytoma, mild, moderate, or severe as defined by increasing cellular pleomorphism, number of mitoses, nuclear size, and nuclear hyperchromatism. Nuclear morphometric characteristics were measured. The clinical and pathologic data of 125 patients were compared using Kaplan-Meier estimates of survival. Fisher exact test and multivariate regression were used to analyze the association between anaplasia grade and high-risk histologic features.

RESULTS

Increasing grade of anaplasia was associated with decreased overall survival (P = .003) and increased risk of metastasis (P = .0007). Histopathologic features that were associated with anaplasia included optic nerve invasion (P < .0001), choroidal invasion (P < .0001), and anterior segment invasion (P = .04). Multivariate analysis considering high-risk histopathology and anaplasia grading as predictors of distant metastasis and death showed that high-risk histopathology was statistically significant as an independent predictor (P = .01 for metastasis, P = .03 for death) but anaplasia was not (P = .63 for metastasis, P = .30 for death). In the absence of high-risk features, however, severe anaplasia identified an additional risk for metastasis (P = .0004) and death (P = .01).

CONCLUSION

Grading of anaplasia may be a useful adjunct to standard histopathologic criteria in identifying retinoblastoma patients who do not have high-risk histologic features but still have an increased risk of metastasis and may need adjuvant therapy.

Evaluation of the hypersensitivity potential of alternative butter flavorings

Concern has been raised over the association of diacetyl with lung disease clinically resembling bronchiolitis obliterans in food manufacturing workers. This has resulted in the need for identification of alternative chemicals to be used in the manufacturing process. Structurally similar chemicals, 2,3-pentanedione, 2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione, used as constituents of synthetic flavoring agents have been suggested as potential alternatives for diacetyl, however, immunotoxicity data on these chemicals are limited. The present study evaluated the dermal irritation and sensitization potential of diacetyl alternatives using a murine model. None of the chemicals were identified as dermal irritants when tested at concentrations up to 50%. Similar to diacetyl (EC3=17.9%), concentration-dependent increases in lymphocyte proliferation were observed following exposure to all four chemicals, with calculated EC3 values of 15.4% (2,3-pentanedione), 18.2% (2,3-hexanedione), 15.5% (3,4-hexanedione) and 14.1% (2,3-heptanedione). No biologically significant elevations in local or total serum IgE were identified after exposure to 25-50% concentrations of these chemicals. These results demonstrate the potential for development of hypersensitivity responses to these proposed alternative butter flavorings and raise concern about the use of structurally similar replacement chemicals. Additionally, a contaminant with strong sensitization potential was found in varying concentrations in diacetyl obtained from different producers.

Toxicological analysis of limonene reaction products using an in vitro exposure system

Epidemiological investigations suggest a link between exposure to indoor air chemicals and adverse health effects. Consumer products contain reactive chemicals which can form secondary pollutants which may contribute to these effects. The reaction of limonene and ozone is a well characterized example of this type of indoor air chemistry. The studies described here characterize an in vitro model using an epithelial cell line (A549) or differentiated epithelial tissue (MucilAir™). The model is used to investigate adverse effects following exposure to combinations of limonene and ozone. In A549 cells, exposure to both the parent compounds and reaction products resulted in alterations in inflammatory cytokine production. A one hour exposure to limonene+ozone resulted in decreased proliferation when compared to cells exposed to limonene alone. Repeated dose exposures of limonene or limonene+ozone were conducted on MucilAir™ tissue. No change in proliferation was observed but increases in cytokine production were observed for both the parent compounds and reaction products. Factors such as exposure duration, chemical concentration, and sampling time point were identified to influence result outcome. These findings suggest that exposure to reaction products may produce more severe effects compared to the parent compound.

M2/M1 ratio of tumor associated macrophages and PPAR-gamma expression in uveal melanomas with class 1 and class 2 molecular profiles

Macrophages have been found to be negative predictors of outcome in patients with uveal melanoma. In particular, recent studies point toward a disease-progressing role of proangiogenic M2 macrophages in melanomas with monosomy 3. Although most studies implicate a protective effect of PPAR-gamma activation in tumors, PPAR-gamma has also been shown to promote the polarization of M1 macrophages toward the M2 phenotype. The purpose of this investigation was first, to characterize the phenotype of tumor infiltrating macrophages and second, to study PPAR-gamma expression in uveal melanomas with molecular gene expression profile as prognostic predictors for patients' outcome. Twenty specimens from patients with uveal melanoma were analyzed for clinical and histologic tumor characteristics. The molecular RNA profile (class 1 or class 2) was commercially determined. Using immunohistochemical techniques, the specimens were dual labeled for CD68 and CD163. CD68 + CD163- M1 macrophages and CD68 + CD163+ M2 macrophages were analyzed in ten high power fields sparing macrophage-poor areas and a mean value was calculated for each tumor. The tumors were immunostained for von Willebrand factor and the micro vascular density (MVD) was analyzed according to Foss. To assess the proliferative rate of each tumor, Ki67 expression was evaluated in ten high power fields followed by calculation of a mean value. Expression of PPAR-gamma was evaluated using a score from 0 (no staining) to 3 (tumor entirely stained). Statistical analysis and a respective correlation were made between histologic characteristics, molecular profile, type of tumor infiltrating macrophages (M1 vs. M2), MVD, proliferative rate, and PPAR-gamma expression. Our results showed a correlation between the ratio of M2/M1 macrophages and the molecular profile with a ratio of approximately 1 corresponding to molecular class 1 and a ratio of approximately 2 corresponding to molecular class 2 (p = 0.01). The ratio of M2/M1 macrophages was higher in tumors with extraocular extension (p = 0.01). PPAR-gamma was predominantly expressed in the cytoplasm of tumor cells. Its expression showed no association with the molecular RNA profile (p = 0.83). This study confirmed that the ratio of M2/M1 macrophages is another prognostic factor in uveal melanoma. Thus, polarization of macrophages plays an important role for patients' outcome. PPAR-gamma is expressed in uveal melanoma tumor cells and further studies are warranted to determine its role in tumor biology.

[Clinico-pathological correlations: posterior compartment of the eye and orbit]

Diseases of the posterior compartment and the orbit are characterised by histological findings, most of which can be reproduced clinically. Examples are the examination of calcifications in retinoblastoma by ultrasonography. In the present review, histological findings of tumour and other diseases of the posterior ocular compartment and the orbit are presented and correlated with the clinical pictures and imaging techniques: uveal melanoma, choroidal nevus, choroidal metastases, choroidal hemangioma, retinoblastoma, Coat's disease, sympathetic ophthalmia, pleomorphic adenoma (benign mixed tumour) of the lacrimal gland, dacryoadenitis, lymphoma, rhabdomyosarcoma, Langerhans cell histiocytosis, orbital metastases, and phthisical eyes. Histopathology is usually the gold standard for a definitive diagnosis. It is very important for residents and those in training to become familiar with clinico-pathological correlations as these provide insight in pathophysiological processes. Regarding ophthalmic surgery, ophthalmic pathology offers the possibility to study wound healing and complications. A close collaboration between clinicians and ocular pathologists allows for an optimised processing of the submitted tissue and diagnosis. Thus, pre- and postoperative care can also be improved. This outstanding knowledge that ophthalmologists have gained over the last decades and beyond, should be preserved and passed on to the next generations in order to maintain a high standard in ophthalmological care.

2-Butoxyethanol and Benzyl Alcohol Reactions with the Nitrate Radical: Rate Coefficients and Gas-Phase Products

The bimolecular rate coefficients [Formula: see text] and [Formula: see text] were measured using the relative rate technique at (297 ± 3) K and 1 atmosphere total pressure. Values of (2.7 ± 0.7) and (4.0 ± 1.0) × 10^-15 cm³ molecule^-1 s^-1 were observed for [Formula: see text] and [Formula: see text], respectively. In addition, the products of [Formula: see text] and [Formula: see text] gas-phase reactions were investigated. Derivatizing agents O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and N, O-bis (trimethylsilyl)trifluoroacetamide and gas chromatography mass spectrometry (GC/MS) were used to identify the reaction products. For [Formula: see text] reaction: hydroxyacetaldehyde, 3-hydroxypropanal, 4-hydroxybutanal, butoxyacetaldehyde, and 4-(2-oxoethoxy)butan-2-yl nitrate were the derivatized products observed. For the [Formula: see text] reaction: benzaldehyde ((C₆H₅)C(=O)H) was the only derivatized product observed. Negative chemical ionization was used to identify the following nitrate products: [(2-butoxyethoxy)(oxido)amino]oxidanide and benzyl nitrate, for [Formula: see text] and [Formula: see text], respectively. The elucidation of these products was facilitated by mass spectrometry of the derivatized reaction products coupled with a plausible 2-butoxyethanol or [Formula: see text] reaction mechanisms based on previously published [Formula: see text] gas-phase mechanisms.

Irritancy and allergic responses induced by exposure to the indoor air chemical 4-oxopentanal

Over the last two decades, there has been an increasing awareness regarding the potential impact of indoor air pollution on human health. People working in an indoor environment often experience symptoms such as eye, nose, and throat irritation. Investigations into these complaints have ascribed the effects, in part, to compounds emitted from building materials, cleaning/consumer products, and indoor chemistry. One suspect indoor air contaminant that has been identified is the dicarbonyl 4-oxopentanal (4-OPA). 4-OPA is generated through the ozonolysis of squalene and several high-volume production compounds that are commonly found indoors. Following preliminary workplace sampling that identified the presence of 4-OPA, these studies examined the inflammatory and allergic responses to 4-OPA following both dermal and pulmonary exposure using a murine model. 4-OPA was tested in a combined local lymph node assay and identified to be an irritant and sensitizer. A Th1-mediated hypersensitivity response was supported by a positive response in the mouse ear swelling test. Pulmonary exposure to 4-OPA caused a significant elevation in nonspecific airway hyperreactivity, increased numbers of lung-associated lymphocytes and neutrophils, and increased interferon-γ production by lung-associated lymph nodes. These results suggest that both dermal and pulmonary exposure to 4-OPA may elicit irritant and allergic responses and may help to explain some of the adverse health effects associated with poor indoor air quality.

Use of denuder/filter apparatus to investigate terpene ozonolysis

A denuder/filter apparatus was used to collect the gaseous and particulate reaction products from ozonlysis of α-pinene, limonene and α-terpineol in an effort to develop sampling techniques for characterizing indoor environment chemistry. Carboxylic acids found in the particulate phase were derivatized to 2,2,2-trifuoroethylamides by reaction with 3-ethyl-1-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC) and 2,2,2-trifluoroethylamine hydrochloride (TFEA). Carbonyl compounds collected in both gas phase and particulate phase were derivatized to their respective oximes by reaction with O-(2,3,4,5,6-pentafluoro-benzyl)hydroxylamine hydrochloride (PFBHA). The ozonolysis of α-pinene yielded the carboxylic acids: cis-pinonic acid and pinic acid and the proposed carboxylic acids methanetricarboxylic acid and terpenylic acid; the carbonyls: 4-oxopentanal, norpinonaldehyde, pinon aldehyde and the proposed carbonyl methylidenepropanedial. The ozonolysis of limonene yielded the carboxylic acids: limonic acid and pinic acid and the carbonyls: 1-(4-methylcyclohex-3-en-1-yl)ethanone (4AMCH), glyoxal, methyl glyoxal, 4-oxopentanal and 6-oxo-3-(prop-1-en-2-yl)heptanal (IPOH). The ozonolysis of α-terpineol yielded the proposed carboxylic acids: terpenylic acid and homoterpenylic acid and the carbonyls: (5E)-6-hydroxyhept-5-en-2-one, methyl glyoxal and 4-oxopentanal.

Conjunctival stromal tumor: report of 4 cases

PURPOSE

To describe the clinical, histopathologic, immunohistochemical, and ultrastructural features of a case series of benign stromal tumors in the bulbar conjunctiva.

DESIGN

Observational case series.

PARTICIPANTS

Four patients with a conjunctival lesion that were classified histologically as low-grade stromal tumors consisting of spindle-shaped cells with occasional pseudonuclear inclusion and multinucleated cells in a partly myxoid matrix.

METHODS

Four cases of low-grade conjunctival stromal tumors were retrospectively identified in an ophthalmic pathology laboratory database. Patients' records were analyzed for demographic data, clinical appearance, and the postoperative course. Formalin-fixed, paraffin-embedded specimens were routinely processed and stained with hematoxylin and eosin and periodic acid Schiff. Immunohistochemical stains for vimentin, S100, CD34, smooth muscle actin (SMA), CD68, and factor XIIIa were performed. Transmission electron microscopy (TEM) was performed on 3 of the cases.

MAIN OUTCOME MEASURES

Histopathologic evaluation (including immunostains and TEM) and clinical correlation.

RESULTS

All 4 tumors occurred in the bulbar conjunctiva of patients between 41 to 53 years of age. None of the patients developed recurrence after excisional biopsy. Histologically, all tumors exhibited spindle-shaped cells with pseudonuclear inclusions and occasional multinuclear cells. Mitotic figures were not observed. The stroma seemed to be myxoid to collagenous. Immunohistochemical stains were positive for CD34, vimentin, and focally for CD68, but were negative for S100 and SMA.

CONCLUSIONS

We propose to classify these benign lesions, which share distinct histopathologic features, as "conjunctival stromal tumors." A reactive/inflammatory component needs to be considered in the pathogenesis of this lesion.

Hydroxyl radical yields from reactions of terpene mixtures with ozone

Chamber studies were conducted to quantify hydroxyl radical (OH·) yields and to determine whether water vapor affected OH· formation in the reactions of ozone (O(3)) with a single terpene, two-component terpene mixtures, and a commercial pine oil cleaning product (POC). Solid-phase microextraction fibers (SPME) were used for sampling the terpenes and the 2-butanone formation from the hydroxyl reaction with 2-butanol as a measure of OH· yields. Analyses were performed using gas chromatography with flame ionization detection. The individual terpenes' OH· yields from α-terpineol, limonene, and α-pinene were 64 ± 8%, 64 ± 6%, and 76 ± 6%, respectively. OH· yields were also measured from two-component mixtures of these terpenes. In each mixture that contained α-terpineol, the overall OH· yield was lower than the modeled OH· yields of the individual components that comprised the reaction mixture. Reactions of a commercial POC with O(3) were also studied to determine how the individual terpenes react in a complex mixture system, and an OH· formation yield of 51 ± 6% was measured. Relative humidity did not have a significant effect on the OH· formation in the mixtures studied here.

PRACTICAL IMPLICATIONS

The data presented here demonstrate that mixtures may react differently than the sum of their individual components. By investigating the chemistry of mixtures of chemicals in contrast to the chemistry of individual compounds, a better assessment can be made of the overall impact cleaning products have on indoor environments.

Reaction rates of ozone and terpenes adsorbed to model indoor surfaces

Reaction rates and reaction probabilities have been quantified on model indoor surfaces for the reaction of ozone with two monoterpenes (Δ(3) -carene and d-limonene). Molar surface loadings were obtained by performing breakthrough experiments in a plug-flow reactor (PFR) packed with beads of glass, polyvinylchloride or zirconium silicate. Reaction rates and probabilities were determined by equilibrating the PFR with both the terpene and the ozone and measuring the ozone consumption rate. To mimic typical indoor conditions, temperatures of 20, 25, and 30°C were used in both types of experiments along with a relative humidity ranging from 10% to 80%. The molar surface loading decreased with increased relative humidity, especially on glass, suggesting that water competed with the terpenes for adsorption sites. The ozone reactivity experiments indicate that higher surface loadings correspond with higher ozone uptake. The reaction probability for Δ(3) -carene with ozone ranged from 2.9 × 10(-6) to 3.0 × 10(-5) while reaction probabilities for d-limonene ranged from 2.8 × 10(-5) to 3.0 × 10(-4) . These surface reaction probabilities are roughly 10-100 times greater than the corresponding gas-phase values. Extrapolation of these results to typical indoor conditions suggests that surface conversion rates may be substantial relative to gas-phase rates, especially for lower volatility terpenoids.

PRACTICAL IMPLICATIONS

At present, it is unclear how important heterogeneous reactions will be in influencing indoor concentrations of terpenes, ozone and their reaction products. We observe that surface reaction probabilities were 10 to 100 times greater than their corresponding gas-phase values. Thus indoor surfaces do enhance effective reaction rates and adsorption of terpenes will increase ozone flux to otherwise low-reactivity surfaces. Extrapolation of these results to typical indoor conditions suggests that surface conversion rates may be substantial relative to gas-phase rates, especially for lower volatility terpenoids.

THE SPECIFICITY OF KERATINS

Kerateine and metakeratin were prepared from wool, chicken feathers and human hair. Chemical analyses revealed that the compounds are closely related. The results of serological studies disclose that species specificity is an individual characteristic of the keratins employed and that the specificity observed is dependent on the redox state of the sulfhydryl groupings in the protein molecule.

Evaluation of dicarbonyls generated in a simulated indoor air environment using an in vitro exposure system

Over the last two decades, there has been increasing awareness regarding the potential impact of indoor air pollution on health. Exposure to volatile organic compounds (VOCs) or oxygenated organic compounds formed from indoor chemistry has been suggested to contribute to adverse health effects. These studies use an in vitro monitoring system called VitroCell, to assess chemicals found in the indoor air environment. The structurally similar dicarbonyls diacetyl, 4-oxopentanal (4-OPA), glyoxal, glutaraldehyde, and methyl glyoxal were selected for use in this system. The VitroCell module was used to determine whether these dicarbonyls were capable of inducing inflammatory cytokine expression by exposed pulmonary epithelial cells (A549). Increases in the relative fold change in messenger RNA expression of the inflammatory mediators, interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha) were identified following exposure to diacetyl, 4-OPA, glyoxal, glutaraldehyde, and methyl glyoxal when compared to a clean air control. Consistent results were observed when the protein levels of these cytokines were analyzed. Exposure to 4-OPA significantly elevated IL-8, IL-6, GM-CSF, and TNF-alpha while glutaraldehyde caused significant elevations in IL-6, IL-8, and TNF-alpha. IL-6 and IL-8 were also significantly elevated after exposure to diacetyl, glyoxal, and methyl glyoxal. These studies suggest that exposure to structurally similar oxygenated reaction products may be contributing to some of the health effects associated with indoor environments and may provide an in vitro method for identification and characterization of these potential hazards.

Investigating ozone-induced decomposition of surface-bound permethrin for conditions in aircraft cabins

The reaction of ozone with permethrin can potentially form phosgene. Published evidence on ozone levels and permethrin surface concentrations in aircraft cabins indicated that significant phosgene formation might occur in this setting. A derivatization technique was developed to detect phosgene with a lower limit of detection of 2 ppb. Chamber experiments were conducted with permethrin-coated materials (glass, carpet, seat fabric, and plastic) exposed to ozone under cabin-relevant conditions (150 ppb O(3), 4.5/h air exchange rate, <1% relative humidity, 1700 ng/cm(2) of permethrin). Phosgene was not detected in these experiments. Reaction of ozone with permethrin appears to be hindered by the electron-withdrawing chlorine atoms adjacent to the double bond in permethrin. Experimental results indicate that the upper limit on the reaction probability of ozone with surface-bound permethrin is approximately 10(-7). Extrapolation by means of material-balance modeling indicates that the upper limit on the phosgene level in aircraft cabins resulting from this chemistry is approximately 1 microg/m(3) or approximately 0.3 ppb. It was thus determined that phosgene formation, if it occurs in aircraft cabins, is not likely to exceed relevant, health-based phosgene exposure guidelines.

PRACTICAL IMPLICATIONS

Phosgene formation from ozone-initiated oxidation of permethrin in the aircraft cabin environment, if it occurs, is estimated to generate levels below the California Office of Environmental Health Hazard Assessment acute reference exposure level of 4 microg/m(3) or approximately 1 ppb.

Surface chemistry reactions of alpha-terpineol [(R)-2-(4-methyl-3-cyclohexenyl)isopropanol] with ozone and air on a glass and a vinyl tile

The surface-phase reaction products of alpha-terpineol [(R)-2-(4-methyl-3-cyclohexenyl)isopropanol] with ozone (O(3)), air or nitrogen (N(2)) on both a glass and vinyl flooring tile were investigated using the recently published FLEC Automation and Control System (FACS). The FACS was used to deliver O(3) (100 ppb), air or N(2) to the surface at a specified flow rate (300 ml/min) and relative humidity (50%) after application of a 1.6%alpha-terpineol solution in methanol. Oxidation products were detected using the derivatization agents: O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine and N,O-bis(trimethysilyl)trifluoroacetamide. The positively identified reaction products were glyoxal, methylglyoxal and 4-oxopentanal. The proposed oxidation products based on previously published VOC/O(3) reaction mechanisms were: 4-methylcyclohex-3-en-1-one, 6-hydroxyhept-en-2-one, 3-(1-hydroxy-1-methylethyl)-6-methylcyclohex-2-en-1-one) and one surface-enhanced reaction product: 5-(1-hydroxy-1-methylethyl)-2-methylcyclohex-2-en-1-one. Though similar products were observed in gas-phase alpha-terpineol/O(3) reactions, the ratio of the reaction products were different suggesting stabilization of larger molecular weight species by the surface. Emission profiles of these oxidation products over 72 h are also reported.

PRACTICAL IMPLICATIONS

Volatile organic compounds (VOCs) can interact with indoor initiators [such as hydroxyl radicals (OH*), ozone and nitrate radicals (NO(3)*)] to form a number of oxygenated by-products in the gas-phase. However, when VOCs are applied to or are present on the surface, heterogeneous chemistry with indoor initiators can also occur. The surface can influence the reaction mechanism to produce new surface reaction products. The work, described here, shows the interaction of alpha-terpineol (major component of pine oil) with ozone and air on both glass and vinyl flooring. These results demonstrated emissions of oxygenated organic compounds as a result of reaction and that further investigations of this chemistry are required to accurately estimate indoor occupant exposures.

Feasibility of detection and quantification of gas-phase carbonyls in indoor environments using PFBHA derivatization and solid-phase microextraction (SPME)

Solid-phase microextraction (SPME) was evaluated for the detection and quantification of the gas-phase carbonyls: citronellal, glyoxal, methylglyoxal, and beta-ionone. Prepared air samples containing the carbonyl compounds were collected at a flow rate of 2.8 L min(-1) in an impinger containing a 25% reagent water/75% methanol collection liquid. The aqueous samples were then derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), extracted with a PDMS/DVB coated SPME fiber, and analyzed by GC-MS. Detection limits with a sample air volume of 76 L were calculated to be 0.03 ppbv, 0.34 ppbv, 0.12 ppbv, and 0.28 ppbv for citronellal, glyoxal, methylglyoxal, and beta-ionone, respectively.