Surgical punctal occlusion with a high heat-energy releasing cautery device for severe dry eye with recurrent punctal plug extrusion.

PURPOSE: To report the rate of recanalization and the efficacy of punctal occlusion surgery with a high heat-energy-releasing cautery device in patients with severe dry eye disease and recurrent punctal plug extrusion. DESIGN: Prospective, interventional case series. METHODS: Seventy puncta from 44 eyes of 28 dry eye patients underwent punctal occlusion with thermal cautery. All patients had a history of recurrent punctal plug extrusion. A high heat-energy-releasing thermal cautery device (Optemp II V; Alcon Japan) was used for punctal occlusion surgery. Symptom scores, best-corrected visual acuity, fluorescein staining score, rose bengal staining score, tear film break-up time, and Schirmer test values were compared before and 3 months after the surgery. Rate of punctal recanalization also was examined. RESULTS: Three months after surgical cauterization, symptom score decreased from 3.9 ± 0.23 to 0.56 ± 0.84 (P < .0001). Logarithm of the minimal angle of resolution best-corrected visual acuity improved from 0.11 ± 0.30 to 0.013 ± 0.22 (P = .003). Fluorescein staining score, rose bengal staining score, tear film break-up time, and the Schirmer test value also improved significantly after the surgery. Only 1 of 70 puncta recanalized after thermal cauterization (1.4%). CONCLUSIONS: Punctal occlusion with the high heat-energy-releasing cautery device not only was associated with a low recanalization rate, but also with improvements in ocular surface wetness and better visual acuity.

Interferometry in the evaluation of precorneal tear film thickness in dry eye.

PURPOSE: To compare tear film thickness between normal subjects and aqueous tear deficiency dry eye patients by tear interferometry. DESIGN: Prospective case-control study. METHODS: Central precorneal tear film thickness was measured noninvasively using an interference thin-film thickness measurement device (Quore MSPA1100; Mamiya-OP). Tear film thickness of 14 eyes from 14 normal subjects and of 28 eyes from 28 aqueous tear deficiency dry eye patients were compared along with noninvasively measured tear meniscus height, DR-1 (Kowa) dry eye severity grading, fluorescein and rose bengal staining scores, tear film break-up time, and Schirmer test results. Among dry eye patients, 13 eyes underwent punctal occlusion, and tear film thickness was compared before and after the surgery. RESULTS: Tear film was significantly thinner in dry eye patients (2.0 ± 1.5 µm) than normal subjects (6.0 ± 2.4 µm; P < .0001). Tear film thickness showed good correlation with other dry eye examinations. After punctal occlusion, tear film thickness increased significantly from 1.7 ± 1.5 µm to 4.9 ± 2.8 µm (P = .001) with the improvement of tear meniscus height, fluorescein and rose bengal staining scores, tear film break-up time, and Schirmer test values. CONCLUSIONS: Interferometric tear film thickness measurement revealed impaired precorneal tear film formation in aqueous tear deficiency dry eyes and was useful for showing the reconstruction of tear film after punctal occlusion surgery. Interferometry of precorneal tear film may be helpful for the evaluation of aqueous tear deficiency in conjunction with other dry eye examinations.

Establishment of a kit-negative cell line of melanocyte precursors from mouse neural crest cells.

We previously established a mouse neural crest cell line named NCCmelb4, which is positive for Kit and negative for tyrosinase. NCCmelb4 cells were useful to study the effects of extrinsic factors such as retinoic acids and vitamin D(3) on melanocyte differentiation, but in order to study the development of melanocytes from multipotent neural crest cells, cell lines of melanocyte progenitors in earlier developmental stages are needed. In the present study, we established an immortal cell line named NCCmelb4M5 that was derived from NCCmelb4 cells. NCCmelb4M5 cells do not express Kit and are immortal and stable in the absence of Kit ligand. They are positive for melanocyte markers such as tyrosinase-related protein 1 and DOPAchrome tautomerase and they contain stage I melanosomes. Interestingly, glial fibrillary acidic protein, which is a marker for glial cells, is also positive in NCCmelb4M5 cells, while NCCmelb4 cells are negative for this protein. Immunostaining and a cell ELISA assay revealed that 12-O-tetradecanoylphorbol 13-acetate (TPA) and cholera toxin (CT) induce Kit expression in NCCmelb4M5 cells. Real-time polymerase chain reaction analysis also demonstrated the induction of Kit mRNA by TPA and CT. Microphthalmia-associated transcription factor mRNA is simultaneously enhanced by the same treatment. Kit induced by TPA/CT in NCCmelb4M5 cells disappeared after the cells were subcultured and incubated without TPA/CT. These findings show that NCCmelb4M5 cells have the potential to differentiate into Kit-positive melanocyte precursors and may be useful to study mechanisms of development and differentiation of melanocytes in mouse neural crest cells.

Effects of ultraviolet light on melanocyte differentiation: studies with mouse neural crest cells and neural crest-derived cell lines.

To evaluate the etiologic role of ultraviolet (UV) radiation in acquired dermal melanocytosis (ADM), we investigated the effects of UVA and UVB irradiation on the development and differentiation of melanocytes in primary cultures of mouse neural crest cells (NCC) by counting the numbers of cells positive for KIT (the receptor for stem cell factor) and for the L-3,4-dihydroxyphenylalanine (DOPA) oxidase reaction. No significant differences were found in the number of KIT- or DOPA-positive cells between the UV-irradiated cultures and the non-irradiated cultures. We then examined the effects of UV light on KIT-positive cell lines derived from mouse NCC cultures. Irradiation with UVA but not with UVB inhibited the tyrosinase activity in a tyrosinase-positive cell line (NCCmelan5). Tyrosinase activity in the cells was markedly enhanced by treatment with alpha-melanocyte-stimulating hormone (alpha-MSH), but that stimulation was inhibited by UVA or by UVB irradiation. Irradiation with UVA or UVB did not induce tyrosinase activity in a tyrosinase-negative cell line (NCCmelb4). Levels of KIT expression in NCCmelan5 cells and in NCCmelb4 cells were significantly decreased after UV irradiation. Phosphorylation levels of extracellular signal-regulated kinase 1/2 in cells stimulated with stem cell factor were also diminished after UV irradiation. These results suggest that UV irradiation does not stimulate but rather suppresses mouse NCC. Thus if UV irradiation is a causative factor for ADM lesions, it would not act directly on dermal melanocytes but may act in indirect manners, for instance, via the overproduction of melanogenic cytokines such as alpha-MSH and/or endothelin-1.