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.     

应用准分子激光行屈光性板层角膜移植术的实验研究

目的：探索准分子激光角膜屈光手术联合板层角膜移植术可行性，为临床研究提供理论依据。方法：对12只实验兔（均右眼）采用联合经植片内皮面准分子激光治疗性角膜切削术（phototherapeutic keratectomy,PTK)，准分子激光屈光性角膜切削术（photorefractive keratectomy,PRK)的板层角膜移植术，结果：观察12周，实验眼的屈光状态改变值在预定的范围内；植片透明，病理组织学证明，植片，植床的交界面胶原纤维排列整齐，炎症反应及排斥反应轻。结论：可以联合屈光手术及板层角膜移植术，有些问题须进一步研究。     

A prospective study investigating the long-term stability of changes in astigmatism following arcuate lamellar keratotomy (ALK): 3-year results

Introduction: The correction of low to moderate astigmatism is possible today by means of photoablation (PRK), while the treatment of moderate and higher astigmatism still involves refractive keratotomy. Experience has shown that cataract surgery, using modern tunnel techniques with self-healing incisions, results in earlier stability in both the refractive outcome and wound healing. In this study, we attempted to combine the advantages of lamellar keratotomy with those of a pair-wise T-incision as arcuate lamellar keratotomy (ALK). Patients and methods: The clinical outcome of 41 patients who underwent ALK was investigate in a prospective study over a period of 3 years. The pre- and postoperative investigations undertaken included the measurement of astigmatism using a Zeiss keratometer, uncorrected visual acuity, and corrected glare vision using a Humphrey autorefractor. All patients had astigmatism between 2.0 and 7.0 D. Together with a uniform arcuate incision, we used 7 mm (n = 26) and 8 mm (n = 15) mm zones for correction. Results: The average preoperative astigmatism was 4.01 ± 1.90 (median, 3.50) D. After a 3-year follow-up the average postoperative astigmatism was 1.59 ± 1.29 (median, 1.38) D. The astigmatic change induced (Jaffé) after 3 years was about 3.23 ± 2.23 (median, 3.16) D. The average uncorrected visual acuity (log MAR) before ALK was 0.20 ± 0.12 (median, 0.22) and after follow-up, 0.41 ± 0.14 (median, 0.39). Corrected glare vision before surgery was 0.23 ± 0.19 (median, 0.10) and afterwards, 0.25 ± 0.22 (median, 0.14). Conclusions: Arcuate lamellar keratomy (ALK) stood the test as a routine clinical procedure for correction of moderate astigmatism with stable postoperative functional outcomes. We did not find impairment of glare vision following this procedure.      

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.     

飞秒激光辅助的大气泡法深板层角膜移植术治疗圆锥角膜后视觉质量

目的 观察飞秒激光辅助的大气泡法深板层角膜移植术(deep anterior lamellar keratoplasty,DALK)治疗圆锥角膜的视觉质量.方法 使用自身对照观察法,纳入30例(50眼)圆锥角膜患者,均行飞秒激光下大气泡法DALK治疗,随访1 a观察疗效.结果 30例(50眼)患者均顺利完成手术,术后早期术眼角膜植片均透明,角膜生理厚度恢复,植片与植床后弹力层贴合较好;术后7d、1个月、6个月、1 a患眼裸眼视力、最佳矫正视力均高于术前(均为P＜0.05),术后不同时间点间差异均无统计学意义(均为P＞0.05).术后不同时间点角膜曲率、角膜散光均较术前显著降低,角膜最薄点厚度较术前显著增加(均为P＜0.05),术后7d、1个月、6个月、1 a间各指标差异均无统计学意义(均为P＞0.05).术前内皮细胞密度为(2989.34±294.52)个·mm.,术后1 a为(2821.19±325.51)个·mm-2,角膜内皮细胞丢失率为(5.62±0.56)％,术后7d、1个月、6个月、1 a间差异不显著(均为P＞0.05).术中未见并发症发生;术后1眼伤口哆开,1眼缝线松弛,1眼发生基质层免疫排斥反应,未见其他并发症发生.结论 圆锥角膜行飞秒激光辅助的大气泡法DALK治疗,疗效确切,安全性高,是中晚期患者较佳的术式选择.     

Congenital ichthyosis in a Libyan child with ophthalmic manifestations

This report presents a Libyan child with congenital ichthyosis of the recessive lamellar variety complicated by severe ectropion of both upper and lower eyelids. Over a period of 12 months the degree of ectropion diminished and the anterior segments of the eyes were preserved using regular lubricating drops, vitamin A ointment and intermittent topical antibiotic therapy. Despite the pronounced initial upper eyelid ectropion no surgery was required to relieve the ectropion or prevent corneal exposure.     

Structural and biochemical basis for the UVB-induced alterations in epidermal barrier function

Ultraviolet light (UVR) induces a myriad of cutaneous changes, including delayed disruption of the permeability barrier with higher doses. To investigate the basis for the UVB-induced barrier alteration, we assessed the epidermal lamellar body secretory system at various time points before and after barrier disruption with a single high dose of UVB (7.5 MED) to murine epidermis. Morphological data were correlated with changes in epidermal proliferation and lipid synthesis, indicative of lamellar body generation. Twenty-four hours following UVB, the stratum corneum (SC) is normal, but a layer of abnormal, vacuolated, and lamellar body (LB)-deficient cells is present, immediately beneath the stratum granulosum (SG)/SC interface. Immediately subjacent to this band of damaged cells, normal keratinocytes that contain intact LBs are present. By 72 h, concomitant with the appearance of a barrier abnormality, extensively damaged cells persist at the SC/SG interface, and abnormal lamellar membrane structures appear in the lower SC. Upper stratum spinosum (SS) and lower SG cells appear normal, with increased numbers of LBs. A barrier abnormality is still present at 96 h, in association with membrane abnormalities in the lower SC interstices, but up to four normal-appearing, subjacent SG cell layers are present. By 120 h, accelerated LB formation and precocious LB extrusion occur throughout the thickened SG; normal lamellar membranes are present in the lower SC; and barrier recovery is almost complete. Whereas, epidermal synthesis of the major barrier lipid species (i.e., cholesterol, fatty acids, and ceramides, including acylceramides) is reduced or unchanged at 24 and 48 h, it increases significantly 72 h after exposure to UVB. Therefore, the delayed disruption of the permeability barrier following acute UVB exposure results from the arrival of a band of lamellar body-incompetent (i.e., damaged) cells at the SG/SC interface. The subsequent, rapid recovery of the barrier, in turn, results from compensatory hyperplasia of subjacent, undamaged SS/SG cells, generating increased numbers and contents of LB. These results underscore the critical role of the stratum compactum in mediating barrier function, and suggest that beneficial therapeutic effects of UV exposure may be due to enhanced lipid production and barrier regeneration.     

颅眶沟通瘤B超诊断与临床治疗

目的：探索颅眶沟通瘤的Ｂ超诊断方法，以利于临床的诊断及治疗。方法：直接经上眼睑向眶内、颅内、副鼻窦内探查颅眶沟通瘤的声像图表现，有颞骨破坏者经颞部皮肤向眶内、颅内探查颅眶沟通瘤的声像图表现。结果：按肿瘤的主要部分所在的部位及侵袭范围将４６例颅眶沟通瘤分为５型，即：颅眶型１９例，颅眶鼻型３例，眶颅型７例，颅眶 颅内外型１６例，鼻眶颅型１例。手术切除３２例，依肿瘤的分类不同采用不同的手术入路，肿瘤全切除３０例，次全切除２例。结论：Ｂ超诊断颅眶沟通瘤结果可靠，依据Ｂ超诊断按肿瘤的主要部分所在部位及侵袭范围分类，有利于手术方法的选择，提高了肿瘤的全切率。