Faculty Bibliography

PURPOSE: To report a case of bilateral iritis and transillumination defects after laser hair removal of the eyebrows with an alexandrite laser. METHODS: A 41-year-old male presented with bilateral eye pain and mild photophobia 2 days after receiving alexandrite (755 nm) laser epilation of both eyebrows. Examination showed visual acuity of 20/20 in both eyes, 2+ conjunctival injection in both eyes, 1+ cells in the anterior chamber of right eye and trace cells in left eye, poor right pupil dilation, and left pupil without movement. Intraocular pressure and fundus examination were normal. He was diagnosed with iritis and iris atrophy, associated with laser epilation. Topical steroids and cycloplegic drops were prescribed for 1 month. RESULTS: After 1 month of treatment, transillumination defects remained in both eyes, but greater in right. In dim light, the right pupil was 4 mm and oval and the left pupil was 6 mm and round. Visual acuity remained 20/20 in both eyes. CONCLUSION: Laser hair removal of the eyebrows can lead to permanent ocular damage even with eye protection, and should be avoided.

This study's purpose was to investigate whether photochemically crosslinking collagen gel to encapsulate chondrocytes (articular, auricular, costal) would permit new cartilage formation in vivo, and to determine whether this neocartilage had the ability to integrate with existing native cartilage. Chondrocytes from swine were embedded in collagen gel that was photochemically crosslinked using riboflavin and visible light. Controls were collagen gels containing cells that were not crosslinked. Cylindrical implants (0.1 cc) were placed in athymic mice for 4 and 8 weeks. To study integration, the constructs were crosslinked within articular cartilage rings and implanted in the mice. Samples were analyzed in terms of macroscopic, microscopic, and biochemical aspects. Photocrosslinking did not affect the amount of glycosaminoglycan and type II collagen produced by the cells. We found that photochemical crosslinking collagen gel enhances the physical parameters of the gel and permits new cartilage formation that can integrate with existing native cartilage.

BACKGROUND: The potential of motor neuron progenitor cell transplants to preserve muscle tissue after denervation was studied in in vivo and in vitro adult mammalian model of peripheral nerve injury. METHODS: Embryonic stem cells were differentiated to induce cholinergic motor neuron progenitors. Flourescent-labeled progenitor cells were injected into the gastrocnemius muscle of Sprague-Dawley rats (n = 10) after denervation by ipilateral sciatic nerve transection. Control rats received injections of either a phosphate-buffered saline solution only (n = 12), murine embryonic fibroblast (STO) cells (n= 6), or undifferentiated embryonic stem cells (n= 6). Muscles were weighed and analyzed at 7 and 21 days using histology, histomorphometry, and immunostaining. RESULTS: Seven days after progenitor cell transplant, both muscle mass and myocyte cross-sectional area were preserved, compared with control muscles, which demonstrated muscle mass reduction to 70 percent and reduction of cross-sectional area to 72 percent of normal. Fluorescent microscopy of transplanted muscles confirmed the presence of motor neuron progenitors. Presynaptic neuronal staining of the transplants overlapped with alpha-bungarotoxin-labeled muscle fibers, revealing the presence of new neuromuscular junctions. By 21 days, muscle atrophy in the experimental muscles was equal to that of controls and no transplanted cells were observed. Co-culture of the motor neuron progenitor cells and myocytes also demonstrated new neuromuscular junctions by immunofluorescence. CONCLUSIONS: Transplanted motor neuron progenitors prevent muscle atrophy after denervation for a brief time. These progenitor cell transplants appear to form new neuromuscular junctions with denervated muscle fibers in vivo and with myocytes in vitro.