Antioxidant and glutathione-related enzymatic activities in rat sciatic nerve

The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutamyl transpeptidase. The relevance of the results obtained and its possible relationship with different neuropathies is discussed. It is concluded that the peripheral nervous tissue is by far less protected than the liver against oxidative damage.     

中心性浆液性脉络膜视网膜病变的PERG．PVEP

用自制的银氯化银钩形电极记录PERG,同步记录PVEP,对照组各波潜伏时,波幅与国外报告结果近似。中浆患眼40%P_m波下降,且与视力下降相关(r>r.05)。b波下降者仅15%,与视力不相关。两者反应的不同,提示PERG较少受外层视网膜病变的影响,能够直接反映内层视网膜的机能状态。但P_m波延迟者,b波多不延迟,未能证明视网膜内传导迟滞。     

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.     

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.     

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.     

Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation

Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg^-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg^-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.     

Sympathetic control of spontaneous defibrillation of the heart

Department of Normal Physiology, Russian National Medical University, Moscow. (Presented by Academician of the Russian Academy of Medical Sciences V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 10, pp. 339–340, October, 1992.     

交感神经亢进引起的心电图改变

植物神经功能失调多见于一些中青年女性 ,临床症状表现为心悸、心前区不适、脉压差小、心电图示 T波异常 ,口服硝酸甘油可缓解 ,体格检查未发现异常