电离辐射对放射工作者职业健康的影响

目的 分析放射工作者外周血象、淋巴细胞微核及染色体畸变情况,为放射工作者职业防护和健康监测提供依据。方法 对2015年、2017年和2019年连续3次接受健康检查的127名放射工作者进行淋巴细胞微核、染色体及血象分析,将其设为放射组。另外选取133名无射线接触史的医务人员设为对照组;结果 放射组中淋巴细胞微核率和染色体畸变率高于对照组,白细胞和血小板计数低于对照组,均具有统计学意义（P < 0.05）。127名放射工作者外周血白细胞总数随着接触电离辐射时间的增长逐渐降低,染色体畸变率逐渐增加,均具有统计学意义（P < 0.05）。损害工龄大于20年的放射工作者染色体畸变率高于低工龄组,不同损害工龄之间比较无统计学意义（P > 0.05）。核医学与介入治疗工种染色体畸变率高于其他工种,具有统计学意义（P < 0.05）。结论 长时间接触低剂量电离辐射可使放射工作者白细胞总数降低和淋巴细胞染色体畸变率增加,应加强放射工作者防护措施以备降低电离辐射损伤程度,特别要加强核医学和介入治疗放射工作人员的职业防护。     

慢性肺源性心脏病人血液触变特性

本文用Low Shear 30流变测定仪,测定了55例肺心病患者全血触变特性的变化,分析了这些变化与肺心病发生和发展的关系。结果表明:肺心病患者血液的触变特性发生了异常改变。HCT、τ_o、η_s、μ、(η_s-μ)、A、ARC均升高,并随病情加重而逐渐明显。其原因主要在于肺心病缺氧所致的继发性红细胞增多及血液氧分压降低,和二氧化碳分压升高所致的红细胞变形性降低。血液触交特性的改变又使血液循环外周阻力增大,右心负荷增加,从而进一步加重了病情的发展。     

The arterial blood supply of the pancreas: a review III. The inferior pancreaticoduodenal artery

Summary This article is the third part of a comprehensive review on the pancreatic arterial blood supply and deals with the inferior pancreaticoducdenal a. The aim of this review is to summarise the anatomical studies, starting from Haller's reports, and to supply as far as possible, with original material, angiographic evidences for the classic anatomical notions. For this purpose, the overall research was carried out by picking out and studying 1015 selective angiographies (celiac trunk and its branches, superior mesenteric a.) taken from the angiographic archives of the Institutes of Radiology of Siena, Rome (Catholic University), and Perugia. Angiographically, the authors observed the inferior pancreaticoduodenal a., present in most instances, as arising from the superior mesenteric a., from the right accessory hepatic a., or from a common trunk with the first or the first two jejunal aa. Some variations of the course have been shown. The authors underline and discuss the discordant opinions still existing regarding the incidence of the different ways the inferior pancreaticoduodenal a. arises and the surgical importance of the variation of origin of this artery.

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La vascularisation artérielle du pancréas : une mise au point. III. L'artère pancréatico-duodénale inférieure

Résumé Cet article est la troisième partie d'une étude détaillée de la vascularisation artérielle du pancréas et traite de l'a. pancréatico-duodénale inférieure. Le but de ce travail est de résumer les études anatomiques, depuis la publication de Haller, et de fournir autant qu'il est possible, avec un matériel original, les preuves angiographiques des notions anatomiques classiques. Pour cela, la recherche complète a été menée sur le choix et l'ðude de 1015 angiographies sélectives (tronc coeliaque et ses branches, a. mésentérique supérieure) tirées des archives angiographiques des instituts de radiologie de Sienne, Rome (université catholique) et Pérouse. Sur les angiographies les auteurs ont observé l'a. pancréatico-duodénale inférieure, présente dans la plupart des cas, naissant de l'a. mésentérique supérieure, de l'a. hépatique droite accessoire, ou d'un tronc commun avec la première ou les deux premières aa. jéjunales. Quelques variantes ont été montrées dans son trajet. Les auteurs soulignent et discutent les opinions encore divergentes sur la fréquence des différentes origines de l'a. pancréatico-duodénale inférieure et sur leur importance chirurgicale.

     

Pulse wave reflection at the collapsed segment of an artery in Riva-Rocci's method

Summary The contours of pressure and flow of a pulse wave arriving at the entrance of a collapsed segment of an elastic tube can be described by application of the basic laws of reflection. The collapsed segment acts like a valve. It is opened by the pressure of the pulse wave when the pressure within the tube becomes higher than the collapse pressure, i.e. the pressure exerted on the segment from outside. This opening of the collapsed segment suddenly changes the sign of the pulse wave reflection from positive to negative; thus a typical contour change of the pulse proximal to the segment is observed. The most obvious effect is a reduction of the pulse pressure. The extent of this reduction is a function of the collapse pressure.A typical example of this phenomenon can be observed in an artery proximal to the segment which is collapsed due to the pressure exerted by an inflated Riva-Rocci cuff. The effect is explained by the assumption that the sign of reflection changes when the pressure of the pulse wave crosses the level of the cuff pressure. This explanation is supported by the results of model experiments.     

The Krotkoff sound

As the auscultatory method of blood pressure measurement relies fundamentally on the generation of the Korotkoff sound, identification of the responsible mechanisms has been of interest ever since the introduction of the method, around the turn of the century. In this article, a theory is proposed that identifies the cause of sound generation with the nonlinear properties of the pressure-flow relationship in, and of the volume compliance of the collapsible segment of brachial artery under the cuff. The rising portion of a normal incoming brachial pressure pulse is distorted due to these characteristics, and energy contained in the normal pulse is shifted to the audible range. The pressure transient produced is transmitted to the skin surface and stethoscope through deflection of the arterial wall. A mathematical model is formulated to represent the structures involved and to computer the Korotkoff sound. The model is able to predict quantitatively a range of features of the Korotkoff sound reported in the literature. Several earlier theories are summarized and evaluated.     

血脂与体外血栓形成的关系

应用国产ＤＪＨ－Ｉ型调速单型血栓形成仪，对４７４名４５岁以上成人体外血栓形成进行了检测，同时检查血脂水平。另外对部分隐性体外血栓阳性者及正常人的红细胞膜荧光偏振度（Ｐ）和微粘度（η）进行比较。结果表明：隐性体外血栓阳性者中血脂增高者为５７／１０９（５４．１２％），其中一级血栓３２／７５（４２．６％），二级血栓１１／１６（６８．７％），三级血栓１４／１８（７７．７％）。红细胞膜Ｐ和η在隐性体外血栓阳性者与正常人之间有显著差异（Ｐ＜０．０５）。提示：隐性体外血栓检测对临床心脑血管的血栓性疾病的早期预防、治疗有较大的参考价值     

Functional imaging of the brain using single photon emission computerized tomography (SPECT)

Summary The use of tracers is an important technique available for studying cerebral function. Changes in signal are large, but as a result of its photon limited nature, the measurement of this signal is limited: spatially, temporally and in terms of accuracy. The most commonly used single photon (SPECT) system (as apposed to positron) is that with a rotating gamma camera, although multi-headed devices and special purpose rings are now also commonly available. The problems of obtaining good functional information are however identical. Firstly the devices need to be optimised in terms of resolution and sensitivity. Secondly several sources of error, notably those associated with scatter, attenuation and limited spatial resolution, need to be corrected, with the aim of obtaining quantitative estimates of radioactivity concentration. Finally such quantitative estimates need to be converted into meaningful estimates of physiological variables by use of an appropriate model. The general aim of many SPECT measurements is to estimate blood flow for example using Tc-99m labelled HMPAO as a tracer. Good results have been obtained in many clinical conditions: stroke, dementia, tumour and epilepsy, for example. Many other tracers are also available, for example to measure density of receptor sites. The use of SPECT in conjunction with other techniques after image registration is suggested as being an essential tool in extracting maximal clinical information.     

Studies on subcutaneous fat necrosis of the newborn

Summary Biopsy specimens from the skin and subcutaneous fat tissue of four cases with neonatal subcutaneous fat necrosis were made and investigated by light and electron microscopy at 2, 4, and 6 weeks, and 5 months (Case 2) from the onset of the disease. Three stages of ultrastructural change of fat cells were observed. The evolution of crystal formation in the fat cells was seen and phagocytosis of crystals and fat droplets by macrophages and foreign-body giant cells was also noted. In the light microscope accumulation of calcium concretions in the spaces between and inside the fat cells was found. In the electron microscope we detected foci of highly electrondense granules, which were similar in distribution and structure to calcium salts stained with the von Kossa method. Changes in small and medium size blood vessels were observed.This work was written during a stay supported by Max-Planck-Gesellschaft from Dec. 1. 1973 to March 31. 1975 in the Max-Planck-Institut für Klinische und Physiologische Forschung (W.G. Kerckhoff-Institut), Bad Nauheim, West Germany (Director: Prof. Dr. Wolfgang Schaper)     

Sympathoinhibition by rilmenidine in conscious rabbits: involvement of α2-adrenoceptors

Summary Cardiovascular and sympathetic nervous system effects of the mixed ₂-adrenoceptor and imidazoline receptor agonist rilmenidine were studied in conscious rabbits chronically instrumented for the recording of the firing rate of renal sympathetic fibers. Separate experiments were carried out on pithed rabbits with electrically stimulated (2 Hz) sympathetic outflow. Drugs were administered intravenously in a cumulative manner.In conscious rabbits, rilmenidine 0.1, 0.3 and 1.0 mg kg^–1 dose-dependently lowered blood pressure, renal sympathetic nerve activity, heart rate and the plasma concentration of noradrenaline and adrenaline. The effect on blood pressure and plasma catecholamines was maximal after 0.3 mg kg^–1 whereas heart rate and renal sympathetic nerve activity decreased further after rilmenidine 1.0 mg kg^–1. Yohimbine 0.1 and 0.5 mg kg^–1, when injected subsequently, attenuated and at the higher dose abolished all effects of rilmenidine. The effects of rilmenidine were also antagonized by the ₂-adrenoceptor antagonist 2-(2,3-dihydro-2-methoxy-1,4-benzodioxin-2-yl)-4,5-dihydro-1H-imidazole HCl (RX821002; 0.1 and 0.5 mg kg^–1). Yohimbine 0.1 and 0.5 mg kg^–1 did not attenuate or attenuated only slightly the decrease of heart rate and renal sympathetic nerve activity produced by infusion of vasopressin. In pithed rabbits with electrically-stimulated sympathetic outflow, yohimbine 0.1 submaximally and yohimbine 0.5 mg kg^–1 maximally increased the plasma noradrenaline concentration.The experiments show by direct measurement of sympathetic nerve firing and plasma catecholamines that rilmenidine causes sympathoinhibition in conscious rabbits, presumably through central sites of action. The antagonism by yohimbine, at doses which are selective for ₂-adrenoceptors (vs. imidazoline receptors), demonstrates the involvement of ₂-adrenoceptors in the sympatho-inhibition.Correspondence to: B. Szabo at the above address     

Does calcium balanced heparin affect blood gas and electrolyte analysis?

The effect of calcium-balanced heparin (471896, CIBA CORNING) on blood gas and electrolyte analysis was evaluated, by comparing with that of sodium heparin (Na heparin). One ml of whole blood was collected into a syringe, which contained calcium-balance heparin (Ca balanced heparin) or Na heparin. 122 pairs of blood samples obtained from 15 patients were analyzed for Na, K, ionized calcium (Ca(++)), total hemoglobin, pH, P(CO)(2), and P(O)(2) by an automatic blood gas and electrolyte analyzer, CIBA CORNING model 288. There was a significant difference ( P < 0.05) in pH, P(CO)(2), Na, and Ca(++) between the two different groups. Ca(++) concentration was significantly less in Na heparin group than in Ca balanced heparin group, probably due to more chelation of Ca(++) by Na heparin than Ca balanced heparin. The present study suggests that the Ca balanced heparin has minimal effect on the blood gas and electrolyte analysis, and is a suitable anticoagulant for the Ca(++) measurement.