Eight-year follow-up of photorefractive keratectomy for myopia

PURPOSE: We evaluated 8-year results of excimer laser photorefractive keratectomy (PRK) for myopia in terms of stability and late complications. METHODS: Ninety-two myopic eyes of 55 patients were treated with a single-step method using an Aesculap-Meditec MEL 60 excimer laser with a 5.0-mm ablation zone. Treated eyes were divided into three groups according to preoperative refraction: low myopes (< or = -6.00 D), medium myopes (-6.10 to -10.00 D), and high myopes (>-10.00 D). RESULTS: Change in myopic regression stabilized in all myopia groups within 12 months, although a small myopic shift occurred up to 8 years after PRK. Mean change in refraction between 2 and 8 years was -0.42 +/- 0.48 D for low myopes, -0.37 +/- 0.34 D for medium myopes, and -0.41 +/- 0.50 D for high myopes. The percentage of eyes within +/- 1.00 D of emmetropia 8 years after PRK was 78.3% in the low myopia group, 68.8% in the medium myopia group, and 57.1% in the high myopia group. One eye lost 2 lines of best spectacle-corrected visual acuity due to irregular astigmatism. In 13.0% of eyes, a residual trace corneal haze was observed, which had no effect on visual acuity. Apart from the loss of 2 lines of BSCVA in one eye, there were no other late complications during the study period. CONCLUSIONS: The mean change in refraction between 2 and 8 years was less than -0.50 D, regardless of preoperative refraction, and may be attributed to natural age-related refractive change. The appearance of residual corneal haze after 8 years correlated with the amount of myopic correction. PRK was a safe and stable surgical procedure in this group of patients.     

Diminished callus size and cartilage synthesis in alpha 1 beta 1 integrin-deficient mice during bone fracture healing

Integrins mediate cell adhesion to extracellular matrix components. Integrin alpha 1 beta 1 is a collagen receptor expressed on many mesenchymal cells, but mice deficient in alpha 1 integrin (alpha1-KO) have no gross structural defects. Here, the regeneration of a fractured long bone was studied in alpha1-KO mice. These mice developed significantly less callus tissue than the wild-type (WT) mice, and safranin staining revealed a defect in cartilage formation. The mRNA levels of nine extracellular matrix genes in calluses were evaluated by Northern blotting. During the first 9 days the mRNA levels of cartilage-related genes, including type II collagen, type IX collagen, and type X collagen, were lower in alpha1-KO mice than in WT mice, consistent with the reduced synthesis of cartilaginous matrix appreciated in tissue sections. Histological observations also suggested a diminished number of chondrocytes in the alpha 1-KO callus. Proliferating cell nuclear antigen staining revealed a reduction of mesenchymal progenitors at the callus site. Although, the number of mesenchymal stem cells (MSCs) obtained from WT and alpha 1-KO whole marrow was equal, in cell culture the proliferation rate of the MSCs of alpha 1-KO mice was slower, recapitulating the in vivo observation of reduced callus cell proliferation. The results demonstrate the importance of proper collagen-integrin interaction in fracture healing and suggest that alpha1 integrin plays an essential role in the regulation of MSC proliferation and cartilage production.     

Prevention of experimental corneal allograft rejection in rabbits using cyclosporin-collagen shields

Topical administration of cyclosporin A, a highly hydrophobic cyclic undecapeptide, has been relatively ineffective in preventing corneal allograft rejections due to poor drug penetration. Therefore, we investigated a new continuous-delivery system for cyclosporin A using collagen bandage shields fabricated from porcine scleral tissue. Collagen bandage shields containing 4 mg cyclosporin A were used for the treatment of four corneal allografts embedded in prevascularized rabbit corneas. Four controls were treated with shields containing no cyclosporin A. The shields were changed every 2nd day and signs of rejection were recorded. All controls were rejected by the end of the experiment. Treatment with collagen shields containing cyclosporin A effectively prevented such rejection. The clinical examinations were also confirmed with histopathological analysis. The results indicate that collagen shields can slowly release cyclosporin A and increase the penetration time for the drug. Thus, they are excellent delivery systems for hydrophobic drugs with poor penetration properties.This work was financially supported by the Paulo Foundation, Helsinki, Finland, and by Bausch & Lomb, Inc., Clearwater, Fla, USA     

Successful Percutaneous Balloon Valvuloplasty for Combined Congenital Tricuspid and Pulmonary Stenosis

Percutaneous balloon valvuloplasty was successfully performed in a 13-month-old symptomatic infant with congenital tricuspid and pulmonic valve stenosis. Both valves were dilated in the same setting, resulting in a significant hemodynamic and clinical improvement.     

Hepatitis C virus infection in chronic liver disease and hepatocellular carcinoma in Saudi Arabia

The prevalence of antibody to hepatitis C virus (HCV) was determined in 139 patients with chronic liver disease (CLD) and 42 patients with hepatocellular carcinoma (HCC) during one year at the Riyadh Military Hospital, Saudi Arabia. The anti-HCV was detected in 36 of 96 (37.5%) HBsAg-negative patients with chronic liver disease and six of 43 (13.9%) HBsAg-positive patients with chronic liver disease. In addition, 11 (42.3%) HBsAg-negative hepatocellular carcinoma patients and two of 16 (12.5%) HBsAg-positive hepatocellular patients had antibody to HCV. The anti-HCV prevalence was 1.5% in 4818 healthy blood donors and 1% in 385 antenatal patients. The overall HCV seropositivity of 30.4% in 181 liver disease patients (CLD and HCC) in Saudi Arabia is lower than that reported from European countries.     

中药对过敏性紫癜肾炎患儿血浆内皮素和免疫功能的影响

用中药加雷公藤治疗过敏性紫癜肾炎患儿23例，观察其急性期、缓解期的血浆内皮素和免疫功能，并与单纯应用雷公藤的15例比较，结果中药加雷公藤组缓解或血浆内皮素和IGG、IGA均明显低于雷公藤组；T3细胞明显高于雷公藤组；T4/T8比值明显低于雷公藤组。提示中药加用雷公藤比单独使用雷公藤治疗过敏性紫问肾炎更有利于患儿血浆内皮素水平和免疫功能的恢复。