572例近视眼患者中央角膜厚度测量报告

本文作者在572例(1144只眼)近视眼患者拟行角膜放射状切开(RK)手术前,对角膜不同部位厚度进行了测量,对其值作统计学处理,均值及标准差为0.527±0.037mm,标准误为0.002,说明我国95％的近视眼患者中央角膜厚度范围为0.455—0.600mm。提示我国成人各年龄组左、右眼角膜厚度与左、右眼屈光度、性别、眼别无关。强调RK手术前对角膜厚度测量的重要性,但手术预后优劣为多因素所致。     

A New Approach to Percutaneous Subclavian Venipuncture to Avoid Lead Fracture or Central Venous Catheter Occlusion

Pacemaker and defibrillator leads and central venous catheters placed by commonly recommended techniques have been found to pass through the subclavius muscle, the costocaracoid ligament, or the costoclavicular ligament before entering veins medial to the first rib. Entrapment by these soft tissues subjects leads and catheters to stresses imposed by movements of the ipsilateral upper extremity. Accordingly, a new approach has been developed that introduces the lead or catheter into the subciavian vein near the lateral border of the first rib. This placement avoids soft tissue entrapment and may extend the longevity of leads and catheters.     

Angiography and magnetic resonance imaging of aortic dissection

This review article describes and illustrates the role of angiography and magnetic resonance imaging in the evaluation of aortic dissection. Clinical findings, complications, classification, and treatment of dissection are reviewed as well.     

Primary orthostatic tremor is an exaggeration of a physiological response to instability.

Primary orthostatic tremor (POT) is a rare disorder characterised by an intense sense of unsteadiness upon standing and a 16-Hz tremor in which the timing between tremor bursts in different muscles (unilateral and bilateral) remains constant. Hitherto, similar EMG activity has not been described in healthy subjects and it has been postulated that the oscillations seen in POT are primarily pathological. In this study, EMG was recorded from tibialis anterior in healthy subjects who were made unsteady through vestibular galvanic stimulation or leaning backwards. Under these conditions, a peak at approximately 16 Hz was seen in the coherence between the left and right tibialis anterior. This bilateral coherence was absent when the subjects activated the same muscles when not unsteady. These data indicate the existence of a physiological system involved in organising postural responses under circumstances of imbalance and characterised by a highly synchronised output at approximately 16 Hz. In addition, the results suggest that the core abnormality in POT may be an exaggerated sense of unsteadiness when standing still, which then elicits activity from a 16-Hz oscillator normally engaged in postural responses.     

Surgical results of performing R4 gastrectomy for gastric cancer located in the upper third of the stomach

Because gastric cancers located in the upper third of the stomach are difficult to detect at an early stage, the surgical results remain poor. We performed R4 gastrectomy as a radical procedure for 25 patients, involving complete resection of the latero-aortic and interaorticovenous lymph modes above and below the left renal vein, in combination with the ordinary R2 or R3 gastrectomy (the R4 group). These patients were compared with 156 others who underwent R2 gastrectomy alone (the R2 group). There were no significant differences in operation time, blood loss, or the incidence of complications between the two groups; however, when the survival rates of the patients with tumors invading beyond the subserosa were compared, the 5-year survival rate was found to be significantly higher in the R4 group than in the R2 group. Furthermore, in patients with para-aortic nodal involvement, a significant survival advantage was observed in the R4 group, as compared with the R2 group. These results suggest that the R4 gastrectomy is a rational approach for patients with advanced gastric cancer located in the upper third of the stomach.     

Left internal carotid artery dissection presenting with headache, Collet-Sicard syndrome and sustained hypertension

The baroreflex maintains blood pressure through the glossopharyngeal (IX) cranial nerve. We report a 54-year-old man who developed a left sided headache, hoarseness, dysarthria, dysphagia, and sustained hypertension from a left internal carotid artery dissection. We hypothesise that interruption of the left IX nerve caused hypertension in this patient.     

A群脑膜炎多糖菌苗接种前后流脑流行规律的改变及今后预防对策

本文研究了在使用菌苗预防前后的流行性脑脊髓膜炎流行强度的变迁，年龄、地区及季节分布特点，人群的易感性及带菌率之间的关系，并讨论了今后的预防措施。     

Ultrastructure of the periaqueductal grey matter of the rat: an electron microscopical and horseradish peroxidase study.

The neurons of the mesencephalic periaqueductal grey substance (PAG) in the rat are small and medium sized. The cells are frequently located in small clusters, without interdigitating glial elements and may be connected by direct membrane appositions or by gap junctions. The inner zone of the PAG is cell poor. In many cases, the cytoplasm of the cells is filled with extensive rough endoplasmic reticulum, free ribosomes, Golgi apparatus, and large lysosome-like granules. The nuclei show large indentations. The cells have a high nucleus-cytoplasm ratio. The neuropil is very extensive and particularly rich in large numbers of small unmyelinated axons, dendrites, axonal varicosities, and synaptic connections. Myelinated fibres are relatively scarce. The orientation of the fibres was studied in transverse and horizontal sections, in combination with HRP track tracing experiments. It appeared that throughout the PAG most of the fibres were orientated longitudinally. Quantitation showed that most fibres were present in the inner zones of the PAG. Moreover, the diameter of the fibres adjacent to the aqueduct was smaller than that of the fibres in the peripheral parts of the PAG. The thin unmyelinated fibres made extensive synaptic connections within the PAG. Many synaptic varicosities were found in the neuropil of the PAG. There were four types of synaptic varicosities, characterized by different populations of clear and dense-core secretory granules and by the different morphology of the synaptic specializations. In general, the different types of varicosity were homogeneously distributed in the different parts of the PAG. Electron dense secretory granules, when present, were located at some distance from the synaptic junction. Serial sections revealed varicosities which contained only dense-core secretory granules, without synaptic specializations. The dendrites of PAG neurons generally lacked synaptic spines. Many dendrites, particularly those of neurons located in the peripheral parts of the PAG, were directed toward the aqueduct. The present study shows that the PAG is a very complex brain area. The crisscrossing of axons and dendrites with synaptic connections at considerable distances from the cell bodies render it very difficult to unravel the relationships between the possible sources and destinations of ongoing information. This structure complicates the search for relationships between the functional organization and the cytoarchitectural borders in the PAG area.     

运动性中枢疲劳及乳酸对大鼠大脑皮质神经细胞MCT mRNA表达的影响

目的:探讨运动性中枢疲劳时大鼠大脑皮质MCT1、MCT2mRNA表达的变化以及乳酸对大鼠大脑皮质神经元MCT2mRNA表达的影响。方法:12只Wistar大鼠随机分为对照组和力竭训练1周组,每组6只。通过7天力竭训练建立中枢疲劳模型,观察中枢疲劳时大鼠大脑皮质MCT1、MCT2mR-NA表达变化;采用原代培养的大鼠大脑皮质神经元,观察不同浓度乳酸作用后大鼠大脑皮质神经元MCT2mRNA表达的变化。采用Trizol法提取大脑皮质和神经元总RNA;用SYBRAgreenI荧光定量RT-PCR测定MCT1及MCT2mRNA表达变化。结果:整体水平:力竭训练1周组MCT1mRNA表达无明显变化,而MCT2mRNA表达较对照组显著升高6·35±3·54倍(P<0·05)。细胞水平:乳酸作用后,神经元MCT2mRNA表达在pH=7·25时较对照组(pH=7·35组)升高3·08±2·38倍(P<0·05)。但随着乳酸浓度进一步升高,MCT2mRNA表达无明显增加。结果提示,中枢疲劳可能引发大脑皮质神经元MCT2mRNA表达升高,MCT2基因表达可能与乳酸在中枢疲劳中的作用有关。