颈肩背轴型反流皮瓣修复儿童颏颈瘢痕挛缩

目的探讨修复儿童颏颈瘢痕挛缩一种实用而较理想的方法.方法以颈横动脉浅支为蒂,利用其与旋肩胛动脉皮支的丰富吻合,反流形成超长的轴型皮瓣,向前旋转修复瘢痕松解后的颈前创面.结果采用本皮瓣修复30例儿童颏颈瘢痕挛缩,其中18例随访2年,颈部活动自如,颌骨发育无明显异常,皮瓣色泽良好,效果令人满意.结论本皮瓣轴型血管恒定,反流灌注动脉压高有保证,供瓣面积充足,供区多可直接拉拢缝合,是修复儿童颏颈瘢痕挛缩的较理想方法.     

带蒂胸腹轴型皮瓣早期修复上肢深度蛇伤溃疡

总结胸腹轴型皮瓣早期修复上肢不同部位的深度蛇伤溃疡的经验，评价其应用价值。本组１６例，胸脐皮瓣２例，侧胸腹皮瓣１例，髂腰皮瓣５例，下腹皮瓣６例，下腹分叶皮瓣１例，髂腰加下腹Ｙ形皮瓣１例。术后１例皮瓣远端坏死，３例轻度感染，１６例断蒂后全部成活。随访３个月～７年，皮瓣质地和弹性均好，手功能基本恢复。认为，带蒂胸腹轴型皮瓣是修复上肢深度蛇伤溃疡理想的方法。     

Axial tissue diffusion can account for the disparity between current models of hepatic elimination for lipophilic drugs

An assumption of previous models of hepatic elimination is that there is negligible axial diffusion in the liver. We show, by construction of a stochastic model and analysis of published data, that compounds which are readily diffusible and partitioned into hepatocytes may undergo axial tissue diffusion. The compounds most likely to be affected by axial tissue diffusion are the lipophilic drugs for which the cell membranes provide little resistance and which are highly extracted, thereby creating steep concentration gradients along the sinusoid at steady state. This phenomenon greatly modifies the availability of the compound under conditions of altered hepatic blood flow and protein binding. For moderately diffusible compounds, these relationships are similar to those predicted by the simplistic venous-equilibrium model. Hence, the paradoxical ability of the venous-equilibrium model to describe the steady-state kinetics of lipophilic drugs such as lidocaine, meperidine, and propranolol may be finally resolved. The effects of axial tissue diffusion and vascular dispersion on hepatic availability of drugs are compared. Vascular dispersion is of major importance to the availability of poorly diffusible compounds, whereas axial tissue diffusion becomes increasingly dominant for highly diffusive and partitioned substances.This study was supported by the National Health and Medical Research Council of Australia.     

Variation of multifocal electroretinogram with axial length

INTRODUCTION: The first-order kernel response of multifocal electroretinogram (mfERG) decreases in myopia. A recent study indicates that the flash ERG is also reduced with increased axial length. The aim of this study was to investigate the variations in the first-order response (K1) and the first slice of second-order response (K2.1) across the retina for different axial lengths. METHODS: Thirty healthy subjects with axial length from 23.72 to 28.13 mm (spherical equivalent refractive errors from plano to -10.50 D) were recruited for mfERG measurement using VERIS 4.0. All subjects were fully corrected after cycloplegic refraction and pupils were dilated prior to mfERG recording. There is one trough, n1, and one peak, p1, in the K1 response and three troughs, n1, n2, n3, and three peaks, p1, p2, p3, in the K2.1 response. The amplitudes and implicit times of K1 and K2.1 responses were analysed to determine the characteristic of the responses across retina and the correlation to axial length. RESULTS: The amplitudes of p1 (in the first-order kernel-K1) decreased in the central region and the paracentral region (ring 3) as the axial length increased. The central retinal region showed high rates of reduction in both n1 and p1 (in K1). The amplitudes of n1p1 and n2p2 (in the first slice of the second-order kernel-K2.1) were reduced in the paracentral region (from ring 2 to ring 5) as axial length increased. The average n1 and p1 in K1, and n1p1 and n2p2 in K2.1 mfERG responses are decreased in amplitude by 6-10% per millimetre elongation of axial length. CONCLUSION: Eyes with longer axial lengths, usually with high myopia, have a weaker mfERG response and this attenuation is across the measured retina (from central to paracentral regions) but different kernel responses show a different pattern of attenuation at different retinal eccentricities. The weaker mfERG responses may be related to the morphological changes associated with increased axial length.     

The relationship between the Stiles–Crawford effect of the first kind (SCE-I) and myopia

The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball.     

Measurement of axial edge lift of rigid corneal lenses*

A simple but reliable method was used to measure the axial edge lift at the total diameter over a range of back optic zone radii of several proprietary designs of rigid gas-permeable corneal lens. One of these was found to have a constant axial edge lift construction.     

巩膜环扎加压术后眼轴与屈光状态的改变

目的：探讨视网膜脱离巩膜环扎加压术后眼部屈光状态的改变。方法：用眼科A超、检影验光等对86例原发性视网膜脱离患者的86只患眼手术前1d及术后1、4、12w时的眼轴长度、眼屈光度等进行测量并将结果进行比较。结果：眼轴长度在术后1、4、12w时均较术前增长(P＜0．01)。眼屈光度在术后1、4、12w时均较术前增加，且向负值偏移(术后1、4w，P＜0．015术后12w，P＜0．05)。结论：巩膜环扎加压术后眼轴长度和屈光状态的变化与眼内嵴有关，术后眼轴增长是眼屈光度负值增加的主要因素。