准分子激光原位角膜磨镶术后界面性角膜炎的临床观察

目的 :动态观察准分子激光原位角膜磨镶术 (LASIK)后界面性角膜炎 (DLK)的临床变化 ,同时对其角膜瓣下临床特点及处理方法进行分析。　方法 :对 35 0 0例行LASIK后 1 0例 (1 8只眼 )发生DLK患者进行观察。按3、7、1 4天和 1、2、6个月不同时间进行视力、裂隙灯显微镜检查。　结果 :局部用激素、抗生素治疗 1周 ,症状控制 ,1～ 2个月全部吸收。视力恢复至 1 .0～ 1 .5 (1 6只眼 ) ,0 .8～ 1 .0 (2只眼 )。　结论 :LASIK后DLK常发生在术后 1～ 7天内 ,迟发者偶见 ,男性多于女性 ,以局部激素治疗为主 ,严重患者需全身激素加抗生素治疗。DLK早期须与角膜上皮植入、层间感染鉴别     

角膜上皮移植术治疗陈旧性眼部烧伤的临床应用

应用角膜上皮移植术联合干燥板层角膜移植术治疗１６例１６眼曾行新新供眼材料全板层角膜移植术而失败的陈旧性眼部烧伤患者，术后随访３￣１２个月同时，与新鲜供眼材料的板层角膜移植术术后同期结果相比较。ＫＥＰ－ＤＬＫＰ和ＬＫＰ－Ｆ术后，角膜植片透明率分别为８７．５％和３１．２５％，Ｐ〈０．００５，角膜新生儿血管复发率分别为６．２５％和８１．２５％，Ｐ〈０．００５，持续性角膜上皮损发生率分别为０％和８７．５％     

New Insights into Lamellar Twisting in Transcrystalline Polyethylene

Summary: The morphology of the transcrystalline layer grown by nucleating high density polyethylene on fibers of ultra high molecular weight polyethylene was investigated by microbeam synchrotron X‐ray diffraction. Scanning with a 2 micron step size, it was possible to determine that near the fiber surface, the polymer chains of the transcrystalline layer are oriented at an angle of approx. 41° with respect to the fiber axis. This is consistent with the lamellar fold surface (the {201} plane) being close to perpendicular to the fiber axis. The X‐ray data support gradual twisting of the lamellae about the growth direction (the orthorhombic crystallite b‐axis) at a rate of ～0.85° per micron of radial distance from the fiber surface.

Polarized light micrograph of the transcrystalline layer in a PE/PE composite. The width of the fiber is approximately 20 μm.     

Effects of ageing on the alveolar pores of Kohn and on the cytoplasmic components of alveolar type II cells in monkey lungs

The effects of ageing on the numbers of alveolar pores of Kohn and on the cytoplasmic components of alveolar type II cells were studied in monkey lungs by scanning and transmission electron microscopy. Lung tissue from 26 female and three male pigtail macaques whose ages ranged from 1 month to 31 years (life span is 35 years) was analysed. From the age of 1 month to 10 years there was a significant increase in the number of alveolar pores (r = 0.85, p less than 0. 001); however, between the ages of 14 years to 31 years there was no significant change. In seven animals ranging in age from 1 month to 4 years (mean 2.4 years) the number of pores was 5.8 +/- 3.9 (mean +/- S.D.), whereas in 10 animals aged 16 to 31 years (mean 20.3 years) the number of pores was 32.7 +/- 17.5 (mean +/- S.D.) per alveolar profile, a significant difference (p less than 0.002). In older animals (15-20 years) there was a significant decrease, both in the number of lamellar bodies per alveolar type II cell (p less than 0.01) and in the volume density of lamellar bodies to cytoplasmic volume (p less than 0.05) compared with young animals (1 month to 4.8 years). In older animals, there was also a significant increase in the volume density of a vacuole-like dilatation of the endoplasmic reticulum in alveolar type II cells (p less than 0.05) compared with young animals. These findings suggest impaired pulmonary surfactant production with aging. Both the increased number of alveolar pores and the postulated decrease of surfactant production could play a role in the pathogenesis of pulmonary emphysema.     

A new surgical technique for deep stromal, anterior lamellar keratoplasty

AIMS: To describe a new surgical technique for deep stromal anterior lamellar keratoplasty. METHODS: In eye bank eyes and sighted human eyes, aqueous was exchanged by air, to visualise the posterior corneal surface--that is, the "air to endothelium" interface. Through a 5.0 mm scleral incision, a deep stromal pocket was created across the cornea, using the air to endothelium interface as a reference plane for dissection depth. The pocket was filled with viscoelastic, and an anterior corneal lamella was excised. A full thickness donor button was sutured into the recipient bed after stripping its Descemet's membrane. RESULTS: In 25 consecutive human eye bank eyes, a 12% microperforation rate was found. Corneal dissection depth averaged 95.4% (SD 2.7%). Six patient eyes had uneventful surgeries; in a seventh eye, perforation of the lamellar bed occurred. All transplants cleared. Central pachymetry ranged from 0.62 to 0.73 mm. CONCLUSION: With this technique a deep stromal anterior lamellar keratoplasty can be performed with the donor to recipient interface just anterior to the posterior corneal surface. The technique has the advantage that the dissection can be completed in the event of inadvertent microperforation, or that the procedure can be aborted to perform a planned penetrating keratoplasty.     

生物工程角膜移植治疗感染性角膜炎

目的：观察生物工程角膜移植治疗感染性角膜炎的疗效,评价其临床应用价值和意义。

方法：对我院35例35眼需要进行手术治疗的感染性角膜炎患者分为3组：观察组15例,使用生物工程角膜施行板层角膜移植手术。对照组有两组：对照1组10例,使用保存人角膜施行板层角膜移植手术; 对照2组10例,实施自体结膜瓣遮盖手术。随访3～20mo,观察视力、感染控制情况以及角膜透明度。

结果：观察组15眼术后感染控制,视力不同程度提高,除1眼在随访中发生植片混浊外,其余14眼植片均维持基本透明。对照1组,除1眼病毒性角膜炎因病毒复发导致角膜混浊外,其余9眼角膜植片维持透明。对照2组,除1眼真菌性角膜溃疡感染加重,行眼内容物剜除术,其余角膜溃疡瘢痕修复。

结论：生物工程角膜是一种新型的人角膜替代材料,为解决逐年增长的角膜病患者与短缺的角膜供体之间的矛盾发挥了作用。     

Phacoemulsification in eyes with corneal opacities after deep anterior lamellar keratoplasty

To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens (IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty (DALK), twelve eyes of 12 patients with mild to moderate corneal opacities after DALK and coexisting cataracts were analyzed retrospectively. Phacoemulsification and IOL implantation assisted with anterior capsule staining, as well as non-invasive optical fiber illumination, were performed on all eyes. No intraoperative or postoperative complications were noted. Mean corrected distance visual acuity (logMAR) improved from 1.24±0.17 to 0.73±0.22. Post-phaco intraocular pressure was maintained between 13 to 20 mm Hg in all cases throughout the follow-up period. Mean endothelial cell density decreased from 2258.42±205.94 to 1906.25±174.23 cells/mm2. Phacoemulsification and IOL implantation are safe and valid in eyes with mild to moderate corneal opacities after DALK and coexisting cataracts when assisted with anterior capsule staining and non-invasive optical fiber illumination.     

A ‘toxin mantle’ as defensive barrier in a tropical bird: evolutionary exploitation of the basic permeability barrier forming organelles

Birds in the genus Pitohui and Ifrita carry potent neurotoxins that are most abundant in skin and feathers. It was unknown precisely how or where in the skin these chemicals are stored. Here, we report high‐resolution electron microscopy using OsO₄ staining to visualize the location of alkaloids. Our images suggest that toxic alkaloids accumulate in multigranular bodies of epidermal cells and are likely secreted as part of the avian epidermal barrier, where they are made available for chemical defense.