干性型老年黄斑变性60例随访观察

探刊干性型老年黄斑变性（age-related macular deganeration，AMD)的病变发展特征并 寻找监测AMD病情进展的较敏感指标。 方法：用眼底彩色照相和眼底荧光血管造影(FFA)、明视视网膜电囤(ERG)、FM100-hue 色彩试验及视力检查，对60例(111眼)50~80岁、视力≤1.0的干性型AMD患者进行3～74个月(平均30.2个月)的随访观察。 结果：本组68眼经FFA检查、平均25.6个月随访，其中25%的患眼病灶损害有快慢不一的发展．全部111眼视力在平均30.2个月随访中有18%患眼的视力下降2行以下，且与病灶进展相符，FM100-hue 色彩试验的被随访者中，随访2年以后，其总错误分明显的增加(P<0.01)．63眼的明视ERG在随访过程中无明显变化。 结论：大部分干性AMD患眼的病灶损害和视力可以在较长时间内维持稳定。FM100—hue的总错误分可能为监测AMD病情进展的较敏感指标． （中华眼底病杂志，1997，13：150-152）     

Effect of KB-2796, a new diphenylpiperazine Ca antagonist, on voltage-dependent Ca currents and oxidative metabolism in dissociated mammalian CNS neurons

The effects of KB-2796, 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine-2HCl, on the low- and high-voltage activated Ca²⁺ currents (LVA and HVA I_Ca, respectively) and on oxidative metabolism were studied in neurons freshly dissociated from rat brain. KB-2796 reduced the peak amplitude of LVA I_Ca in a concentration-dependent manner with a threshold concentration of 10⁻⁷ M when the LVA I_Ca was elicited every 30 s in the external solution with 10 mM Ca²⁺. The concentration for half-maximum inhibition (IC₅₀) was 1.9 × 10⁻⁶M. At 10⁻⁵ M or more of KB-2796, a complete suppression of the LVA I_Ca was observed in the majority of neurons tested. There was no apparent effect on the current-voltage (I-V) relationship and the current kinetics. KB-2796 delayed the reactivation and enhanced the inactivation of the Ca²⁺ channel for LVA I_Ca voltage- and time-dependently, suggesting that KB-2796 preferentially binds to the inactivated Ca²⁺ channel. KB-2796 at a concentration of3.0 × 10⁻⁶M also decreased the peak amplitude of the HVA I_Ca without shifting the I-V relationship. In addition, KB-2796 reduced the oxidative metabolism (the formation of reactive oxygen species) of the neuron in a concentration-dependent manner with a threshold concentration of3 × 10⁻⁶M. It is suggested that the inhibitory action of KB-2796 on the neuronal Ca²⁺ influx and the oxidative metabolism, in combination with a cerebral vasodilatory action, may reduce ischemic brain damage.     

高频超声检测颈动脉内膜-中层厚度及外周血管内皮功能评价动脉粥样硬化

目的 探讨高频超声检测颈动脉内膜-中层厚度与肱动脉内皮依赖性舒张功能在动脉粥样硬化中的诊断价值.方法 冠状动脉造影的老年患者69例及青年志愿者20例,分别行颈动脉超声检查,同时采用充气加压法测定肱动脉血流介导的内径扩张值,超声测值与冠脉造影结果对照分析.结果 ①颈动脉内膜-中层厚度值随粥样硬化斑块的增多、冠脉狭窄程度的加重而增高;②动脉粥样硬化患者在内膜-中层厚度值增高之前即可出现内皮功能损伤,肱动脉内径扩张值降低早于内膜-中层厚度值增高之前出现,内径扩张值随冠脉狭窄程度加重而下降.结论 高频超声检测颈动脉内膜-中层厚度、内径扩张值诊断早期动脉粥样硬化敏感性高,并且有助于对冠脉狭窄程度作出判断.     

Moving beyond empiric continuous positive airway pressure (CPAP) trials for central sleep apnea: a multi-modality titration study

There is no universally accepted method to determine effective therapy for central sleep apnea (CSA). Continuous positive airway pressure (CPAP) applied acutely most often does not eliminate apneas and hypopneas. We hypothesized that the application of two or more therapeutic modalities after the diagnostic phase of polysomnography, a multi-modality titration study (MMTS), would identify a successful CSA treatment more often than a standard split-night study (SNS) and obviate the need for additional polysomnograms to determine a successful therapy. We retrospectively analyzed polysomnograms of patients diagnosed with CSA at our Sleep Disorders Center. We defined a therapy trial that resulted in an apnea–hypopnea index < 10 with at least one treatment modality as a therapeutic success. One hundred fifteen patients with CSA were studied. Sixty-six patients (57.4%) underwent a SNS, and 49 patients (42.6%) underwent a MMTS. SNS yielded only 8/66 (12.1%) successes on the first night, whereas a MMTS yielded 19/49 (38.8%) successes (p = 0.001, two-tailed Fishers exact). Patients who underwent a SNS eventually had similar rate of success as patients studied with MMTS (60.6 vs 63.3%, NS), but required more testing. Adaptive servo-ventilation was the most successful modality tested, yielding 36/46 (78.3%) successes. Trials of additional modalities following a failed trial of CPAP often produce a successful option that may guide therapy in patients with CSA. This approach may lead to establishing the diagnosis and treatment plans faster, while reducing unnecessary testing.     

Thickness effects of a carbon-supported platinum catalyst layer on the electrochemical reduction of oxygen in sulfuric acid solution

The influence of the thickness of a carbon-supported platinum catalyst layer on the oxygen reduction reaction (orr) has been studied in sulfuric acid solution by means of a thin-film rotating disk electrode. Pronounced changes in the Pt utilization, electrode activity and the orr kinetics have been observed upon varying the catalyst layer thickness. The thicker film electrode exhibits a higher Pt utilization efficiency and higher activity, and promotes the orr kinetics at potentials relevant to fuel cell operations. The participation of Pt surfaces not in contact with the electrolyte solution in electrochemical reactions via the spillover of adsorbed hydrogen and oxygen species, is proposed to be responsible for the changes. The thicker catalyst layer is likely to modify the Pt particle–particle distance by providing shared Pt sites between adjacent carbon supports, to improve the surface density of active catalyst particles per single carbon support by sharing adjacent catalyst sites, and to increase the ratio of the particle surfaces free of blocking anions to the catalyst|electrolyte interface surfaces. The carbon-supported platinum catalyst layer becomes active at 0.90 V vs RHE only when the catalyst layer is thicker than 1 μm. To provide reasonable activity, the minimum catalyst layer thickness should be around 2–4 μm. These results should be considered in the design of the cathode catalyst layer of polymer electrolyte membrane fuel cells.     

Carotid intima-media thickness in Parkinson's disease.

There have been a few studies and inconsistent results regarding the coincidence of Parkinson's disease (PD) and atherosclerotic diseases, such as cerebrovascular disease. Carotid intima-media thickness (IMT) is a known marker for subclinical atherosclerosis. The aim of this study was to investigate the carotid IMT between PD patients and controls. We studied 43 patients with PD and 86 matched controls. The carotid IMT in PD patients was significantly smaller than in controls (0.796 +/- 0.179 mm vs. 0.913 +/- 0.237 mm, P < 0.05). In multivariate analysis, the carotid IMT was inversely associated with the duration of levodopa medication and the severity of PD. These results suggest that PD patients have a lower risk of atherosclerosis.     

Female patients complaining about hair loss: documentation of defective scalp hair dynamics with contrast-enhanced phototrichogram

BACKGROUND: The complaint of chronic hair loss frequently affects female subjects and there is little or no objective technology available in the general dermatology or even in the hair clinics to guide the observer in the management of the patient. The purpose of this report is to share the results of refined hair growth measurements that were collected in 92 female subjects complaining about hair loss. METHODS: Clinically they were classified as having a patterned hair loss according to Ludwig (L; n=50), diffuse hair loss (D; n=13) or no visible hair loss but complaining of hair shedding (N; n=29). Two scalp sites on the top of the head and one occipital site were investigated after clipping by close-up photography before and after a hair dye (contrast enhancement, CE). Forty-eight hours later a new photograph was taken after CE in view of phototrichogram analysis (CE-PTG). Finally a last hair clip was performed 30 days later and hair thickness and length determined for linear growth measurements (LHGR). RESULTS: Herein we confirm that the top of the head shows usually a higher hair density than occipital sites, a physiological observation that applies both to men and women. From the technological perspective, we also document that CE improves hair detection in all sites. Interestingly, in affected patients (L and D) the relative increase of hair counts after CE was much higher (range +22.4% to +28.3%) compared with apparently unaffected females (N; range +8.2% to +9.7%). This increase in hair counts was only due in part to the presence of less pigmented thinning hair (thickness less than 40 microm). Such thin hairs were found in statistically significantly higher proportions in younger patients with mildly severe (grade I) patterned alopecia (Ludwig: L). In other patients with hair loss and in more severe forms of patterned alopecia - especially in older patients - the thin hair is not detected in abnormal proportions. In all sites slower growth rates and decreased anagen percentages indicate a defective hair replacement programme distinguishing L patterns from diffuse hair loss and from apparently unaffected patients complaining of chronic hair loss. Globally, we also noted that increasing age is associated with significant regression of scalp hair (decreased hair counts, thinner hair and slower LHGR). CONCLUSION: On the basis of the present data together with female data from the literature and our own studies in male subjects, we suggest a three-step mechanism leading to hair loss 1.Shortening of growth phase the hair cycle with maintained thick hair, i.e. more frequent hair cycling that leads to more hair shedding. 2.Intermittent production of short thin hair, i.e. morphological evidence of miniaturisation. 3.Very occasional or almost no hair production, i.e. dormant follicles or irreversible follicular atrophy. Depending on the genetic background, hormonal microenvironment in the scalp and conditioning of individual hair follicle bio-responses, female and male patterned hair loss may end up into different phenotypes.     

病理证实的原发性中枢神经系统淋巴瘤40例临床分析

目的探讨原发性中枢神经系统淋巴瘤（PCNSL）的临床与影像学特点，治疗与预后。方法对40例病理证实的PCNSL的临床与影像学表现、治疗和预后情况进行回顾性分析。结果PCNSL好发于50～60岁男性，急性或亚急性起病。肿瘤单发者占75．0％，多发者占25．0％，多位于脑脊液循环通路附近，即深部结构近脑室（57．5％）或靠近皮质的浅表部位（32．5％）。病理均为B细胞型，有特征性的“血管周围淋巴套”和“星空现象”。临床不具有特异性。头颅MRI多为T1低信号，T2高信号，界限清晰，水肿明显，显著均匀强化占67．6％，厚壁环形强化占13．5％。采用大剂量甲氨蝶呤（HDMTX）化疗者，存活率（75．0％）较未采用者（48．1％）高。平均生存时间14．8个月，复发后69．2％的患者存活不足6个月。结论PCNSL临床表现无特异性，确诊需靠穿刺活体组织检查。治疗首选HDMTX为基础的综合化疗，预后差。     

颅内原发性中枢神经系统淋巴瘤的MRI研究

目的研究颅内原发性中枢神经系统淋巴瘤（PCNSL）的MRI表现特点。资料与方法回顾性分析23例颅内PCNSL的MRI表现。抽取恶性胶质瘤30例、颅内转移瘤30例，共60例归为非PCNSL组作为对照。观察肿瘤部位、分布、信号、形态，并进行统计学分析。结果颅内PCNSL好发于深部脑组织，如胼胝体、丘脑及基底节区，多发病灶多呈区域性分布；肿瘤T2WI多呈等或稍高信号，甚至低信号，扩散加权像（DWI）呈均匀高信号；增强扫描多呈均匀明显强化，肿瘤周围可见“尖突征”。与非PCNSL组之间差异有统计学意义（P〈0．01）。结论颅内PCNSL影像表现多样，但具有一定特征。