严重PDR玻璃体切除术和全视网膜光凝的视力对比

目的：观察严重增殖性糖尿病视网膜病变（proliferative diabetic retinopathy,PDR）患者玻璃体手术和全视网膜光凝的视力对比。方法：将我院93例严重PDR患者随机分为两组,一组接受玻璃体切除＋剥膜＋全视网膜光凝＋黄斑光凝;另一组接受全视网膜光凝＋黄斑光凝,随访1a。结果：术后1a,第一组,视力提高12眼（27.9%）,不变11眼（25.6%）,下降20眼（46.5%）。第二组,提高14眼（28.0%）,不变24眼（48.0%）,下降12眼（24.0%）。两组间视力提高比例无差异。但不变和下降比例差异有显著意义。结论：对于严重的PDR患者,玻璃体切除术可能会带来更高视力下降的风险。     

Intraocular pressure changes following 20G pars‐plana vitrectomy

Purpose: To observe the excursions of short‐term intraocular pressure (IOP) after 20‐G pars‐plana vitrectomy (ppV). Material and methods: In a prospective study, 851 patients (age: mean 63 ± 15 years) underwent unilateral ppV for various vitreoretinal diseases using different endotamponades [Balanced Salt Solution (BSS) 33.1%, Air 7.2%, SF₆ 33.6%, silicon oil 5000 cst 26.1%]. Intraocular pressure was measured in all patients before and at 3, 6, 24 and 48 hr after surgery. Survival analysis was performed to determine the cumulative hazard of IOP changes depending on endotamponade and time point after ppV (Log‐Rang ‐ Mantel Cox; p < 0.0001). Results: At baseline, IOP ranged from 0 to 50 mmHg (mean IOP: 15.3 ± 5.3 mmHg). Mean IOP after surgery revealed a slight elevation (3 hr: 16.5 ± 11.0 mmHg; 6 hr 16.9 ± 9.8 mmHg; 24 hr 19.7 ± 8.0 mmHg; 48 hr 17.3 ± 6.2 mmHg; range: 0–64 mmHg). Silicon oil filling revealed highest mean values at already 3 hr after surgery (21.8 mmHg). Also, BSS filling showed a peak after 3 hr; however, mean values were lower. Equivalent high IOP values as for silicon oil tamponade were found for gas filling; however, maximal peak was reached after 24 hr but not after 3 hr post‐treatment. The cumulative hazard in all patients to reach IOP ≥ 30 mmHg after 24 hr was 23.9%; (IOP ≥ 40 mmHg = 8.2%). Herein, oil filling revealed highest risk at all time points after surgery. The risk of suffering from IOP < 5 mmHg lasting longer than 6 hr was only 1.2% after 20 G vitrectomy. Conclusion: Intraocular pressure measurements after ppV are important to prevent unintentional high IOP, especially within the early phase (3 hr post‐treatment) in eyes with silicon oil filling. Gas filling leads to prolonged IOP increase (24 hr post‐treatment). Long‐lasting hypotony (≥6 hr) is very rare after 20G vitrectomy.     

Endoscopic vitreoretinal surgery: Review of current applications and future trends

Endoscopy provides unique optical properties to circumvent anterior segment opacities and visualize difficult-to-access anatomical regions, including retroirideal, retrolental, ciliary body, and anterior retinal structures. We summarize the basic principles and utilization of endoscopic vitreoretinal surgery, along with recent technological advances in the field base on a structured literature search in Pubmed, Embase, and Google Scholar database up to February, 2020. Endoscopy has been used in the management of retinal detachment, ischemic retinopathies with neovascular glaucoma, severe ocular trauma, endophthalmitis, lens-related disorders in the posterior segment, pediatric vitreoretinal diseases, and implantation of retinal prostheses. Ongoing development of endoscopic technology aims to provide higher resolution images with endoscopes of smaller diameter. New surgical techniques supported by the adoption of endoscopy are available to manage challenging surgical scenarios. Endoscopy can be a useful adjunct to microscope wide-angle viewing systems in the management of complex vitreoretinal diseases.     

玻璃体腔注射康柏西普辅助PPV治疗PDR合并玻璃体积血的疗效

目的：探究玻璃体腔注射康柏西普辅助玻璃体切割术(PPV)治疗增殖型糖尿病视网膜病变(PDR)合并玻璃体积血(VH)的疗效及安全性。

方法：前瞻性随机对照研究。选取2017-02/2019-09本院眼科收治的PDR合并VH患者作为研究对象,随机分为观察组(39例39眼)及对照组(38例38眼)。两组患者均行经睫状体平坦部标准27G PPV治疗,观察组在术前6～7d进行玻璃体腔内注射康柏西普。收集围手术期指标,随访最佳矫正视力(BCVA)、眼压、黄斑中心凹视网膜厚度(CMT),统计手术相关并发症发生情况。

结果：观察组手术时间(74.18±15.26 vs 96.17±14.27min)、出血眼数(8% vs 37%)、硅油填充比例(18% vs 53%)、医源性裂孔发生率(15% vs 47%)少于对照组(P<0.05); 观察组术后1mo(0.33±0.10 vs 0.60±0.21)、3mo(0.29±0.08 vs 0.59±0.30)、6mo(0.28±0.10 vs 0.66±0.25)时BCVA(LogMAR)显著优于对照组(P<0.05); 观察组术后3mo(252.15±56.96 vs 278.41±57.48μm)、6mo(239.65±41.52 vs 268.59±33.71μm)时CMT显著优于对照组(P<0.05); 随访期间观察组及对照组玻璃体出血发生率为5%、21%(P<0.05); 对照组术后3眼(8%)出现牵拉性视网膜脱离,观察组未发生牵拉性视网膜脱离(P>0.05)。

结论：对于PDR合并VH患者,PPV术前辅助使用玻璃体腔注射康柏西普可缩短手术时间,减少术中出血,减轻黄斑水肿,获得更好的视力,有较好的疗效及安全性。     

Organization of the nigrothalamocortical system in the rhesus monkey

The nigrothalamocortical connections and their topography were analyzed by autoradiography and double or triple retrograde labeling with the fluorescent dyes Fast Blue, Diamidino Yellow, and Propidium Iodide. Injections of tritiated leucine into different parts of the substantia nigra (SN) revealed that the medial SN projects to the medial magnocellular subdivisions of the ventral anterior (VAmc) and mediodorsal (MDmc) nuclei of the thalamus while the lateral SN projects to the more lateral and more posterior part of the VAmc, and the paralaminar, parvicellular, and densocellular subdivisions of the mediodorsal nucleus (MDmf, MDpc, and MDdc). With the exception of the MDmf, terminal areas observed in the mediodorsal nucleus were in the form of scattered clusters of grains. Analysis of the thalamus in cases with fluorescent dye injections into the lateral orbital gyrus (Walker's area 11), principal sulcus (area 46), anterior bank of the arcuate gyrus (areas 8 and 45), supplementary motor area (area 6), and motor cortex (area 4) revealed topographic organization of the nigrothalamocortical projection system. The parts of the VAmc and MDmc which receive afferents from the medial part of the SN in turn project to the most anterior regions of the frontal lobe including principal sulcus and orbital cortex. The lateral posterior VAmc, MDmf, MDpc, and MDdc, all of which receive afferents from the lateral part of the SN; project to more posterior regions of the frontal lobe including, in addition to the principal sulcus, the frontal eye field and also areas of the premotor cortex. These findings indicate that the SN has preferential targets in the thalamus and cerebral cortex which are segregated from those of the globus pallidus and cerebellum. Whereas the motor cortex is the primary target of cerebellar output (Asanuma et al., '83b), and the premotor cortex is the target of pallidal output (Schell and Strick, '84), the SN output appears to be directed more anteriorally--to the prefrontal cortex.     

Topographic organization of the ventral striatal efferent projections in the rhesus monkey: An anterograde tracing study

The ventral striatum is considered to be that portion of the striatum associated with the limbic system by virtue of its afferent connections from allocortical and mesolimbic areas as well as from the amygdala. The efferent projections from this striatal region in the primate were traced by using 3H aminoacids and Phaseolus vulgaris-leucoagglutinin (PHA-L). Particular attention was paid to the topographic organization of terminal fields in the globus pallidus and substantia nigra, the projections to non-extrapyramidal areas, the relationship between projections from the nucleus accumbens and the other parts of the ventral striatum, and the comparison between ventral and dorsal striatal projections. This study demonstrates that in monkeys a circumscribed region of the globus pallidus receives topographically organized efferent fibers from the ventral striatum. The ventral striatal fibers terminate in the ventral pallidum, the subcommissural part of the globus pallidus, the rostral pole of the external segment, and the rostromedial portion of the internal segment. The more central and caudal portions of the globus pallidus do not receive this input. This striatal output appears to remain segregated from the dorsal striatal efferent projections to pallidal structures. Fibers from the ventral striatum projecting to the substantia nigra are not as confined to a specific region as those projecting to the globus pallidus. Although the densest terminal fields occur in the medial portion, numerous fibers also extend laterally to innervate the dorsal stratum of dopaminergic neurons of the substantia nigra and the retrorubral area. Furthermore, they project throughout the rostral-caudal extent of the substantia nigra. Projections from the medial part of the ventral striatum reach the more caudally located pedunculopontine tegmental nucleus. Thus unlike the above described terminals in the globus pallidus, the ventral striatum project widely throughout the substantia nigra, a fact that indicates that they may contribute to the integration between limbic and other output systems of the striatum. Finally, the ventral striatum projects to non-extrapyramidal regions including the bed nucleus of the stria terminals, the nucleus basalis magnocellularis, the lateral hypothalamus, and the medial thalamus.     

Tonic Activation of NMDA Receptors Causes Spontaneous Burst Discharge of Rat Midbrain Dopamine Neurons In Vivo

Midbrain dopamine neurons in vivo discharge in a single-spike firing pattern or in a burst-firing pattern. Such activity in vivo strikingly contrasts with the pacemaker activity of the same dopamine neurons recorded in vitro. We have recently shown that burst activity in vivo of midbrain dopamine neurons is due to the local activation of excitatory amino acid receptors, as microapplication of the broad-spectrum antagonist of excitatory amino acids, kynurenic acid, strongly regularized the spontaneous firing pattern of these dopamine neurons. In the present study, we investigated which subtypes of excitatory amino acid receptors are involved in the burst-firing of midbrain dopamine neurons in chloral hydrate-anaesthetized rats, Iontophoretic or pressure microejections of 6-cyano,7-nitroquinoxaline-2,3-dione (CNQX), a non- N -methyl- d -aspartate (NMDA) receptor antagonist, did not alter the spontaneous burst firing of dopamine neurons ( n = 36). In contrast, similar ejections of (±)2-amino,5-phos-phonopentanoic acid (AP-5), a specific antagonist at NMDA receptors, markedly regularized the firing pattern by reducing the occurrence of bursts ( n = 52). In addition, iontophoretic ejections of NMDA, but not kainate or quisqualate, elicited a discharge of these dopamine neurons in bursts ( n = 20, 12 and 14, respectively). These data suggest that burst-firing of midbrain dopamine neurons in vivo results from the tonic activation of NMDA receptors by endogenous excitatory amino acids. In view of the critical dependency of catecholamine release on the discharge pattern of source neurons, excitatory amino acid inputs to midbrain dopamine neurons may constitute a major physiological substrate in the control of the dopamine level in target areas.     

Prefrontal Lobe-Substantia Nigra Projection in Human Cerebrum

Abstract: A PF-SN projection in the human cerebral neocortex was studied and the following results obtained. The PF-SN projection tract originates mainly from areas 9 and 10 and probably also from areas 46 and 47, and passes through the ipsilateral frontopontine tract. The main projecting area is the intermedial region of the pars compacta in the SN in a medio-lateral direction. The PF-SN projection fibers exist in quantities, possibly equal to those of the striatum-SN projection fibers. Fibers projecting from areas of the cerebral neocortex other than the PF to the pars compacta in the SN are likely to be absent.     

The apparent autoxidation rate of catechols in dopamine-rich regions of human brains increases with the degree of depigmentation of substantia nigra

Summary The concentrations of the 5-S-cysteinyl adducts of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylalanine (DOPA) and the levels of noradrenaline (NA), DA, DOPAC and DOPA were determined in the putamen (PUT), caudate nucleus (CN) and substantia nigra (SN) of human post mortem brains with or without depigmentation and degeneration of the SN. The levels of DA, DOPAC and DOPA decreased with the degree of depigmentation and degeneration in the three brain regions while NA levels only decreased in SN and PUT. In general, the concentrations of the 5-S-cysteinyl adducts did not differ, but the ratios of 5-S-cysteinyl-DA/DA, 5-S-cysteinyl-DOPAC/DOPAC and 5-S-cysteinyl-DOPA/DOPA were higher in patients with a more depigmentated and degenerated SN, except for the 5-S-cysteinyl-DA/DA ratio in the PUT. Higher ratios were also found in the cell body areas compared to the neuron terminal areas.Thus depigmentation and degeneration of dopaminergic SN neurons, seem to be correlated to enhanced rates of autoxidation, possibly due to an impaired antioxidant capacity.     

γ-Aminobutyric acid release in the globus pallidus in vivo after a 6-hydroxydopamine lesion in the substantia nigra of the rat

This experiment was designed to determine whether the release of γ-aminobutyric acid (GABA) in the globus pallidus (GP) is affected by a lesion of the nigrostriatal pathway. Rats were lesioned with 6-hydroxydopamine 4 weeks prior to study of the in vivo release of GABA. A microdialysis probe was stereotaxically implanted in halothane-anesthetized animals in a vertical position on both GPs. The perfusates were analyzed for their GABA content with a high performance liquid chromatography technique. Compared to unlesioned controls, a marked decrease in the overflow of GABA was observed in the GP contralateral to the lesion, whereas the ipsilateral GP showed a slight increase. The differences between the sides were exaggerated after KCl (100 mmol) administration. The results are discussed in terms of a possible bilateral influence of dopamine terminals in the striatum on GABA transmission.