Effects of N-acetylcysteine on bacterial clearance

Abstract. The aim of this study was to investigate whether the oxygen radical scavenger N -acetylcysteine ( N -AC) impairs bacterial clearance, thus predisposing the host to increased risk of disease. Blood clearance of Escherichia coli and organ colonization were investigated in anaesthetized rabbits after pretreatment with N -AC (250 mg kg^-1 body weight, n = 16) and in sham-operated animals ( n = 12). To enable quantification of the clearance process, defined numbers of exogenous E. coli [1.3 times 108 colony-forming units (CFUs)] were injected intravenously. Parameters monitored were kinetics of bacterial elimination from the blood, and polymorphonuclear leucocyte (PMN) oxidative burst activity. Samples of liver, kidney, spleen and lung were collected for bacterial counts. Compared with controls, pretreatment with N -AC resulted in delayed bacterial elimination from blood and higher organ colonization with increased numbers of E. coli in liver, lung and kidney ( P < 0.05). N -AC treatment was associated with a suppressed PMN oxidative burst activity. Impaired bacterial clearance and enhanced organ colonization in N -AC-treated animals correlated with reduced oxidative burst activity, suggesting impaired granulocyte-dependent bacterial killing due to N -AC application.     

Cerebral blood flow, cerebral metabolic rate of oxygen and relative CO2 reactivity during neurolept anaesthesia in patients subjected to craniotomy for supratentorial cerebral tumours

In 10 patients subjected to craniotomy for supratentorial cerebral tumours in neurolept anaesthesia, cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured twice peroperatively by a modification of the Kety & Schmidt technique, using 133Xe. The relative CO2 reactivity was assessed indirectly as the % change of the arteriovenous oxygen difference (AVDO2) per mm change in PaCO2. The patients were premedicated with diazepam 10-15 mg perorally. For induction, thiopentone 4-6 mg/kg, droperidol 0.2 mg/kg and fentanyl 5 micrograms/kg were used, and for maintenance N2O 67% and fentanyl 4 micrograms/kg/h. During the first flow measurement the median and range of CBF was 30 ml/100 g/min (range 17-45), of AVDO2 8.0 vol % (range 4.1-9.5), and of CMRO2 2.28 ml O2/100 g/min (range 1.57-2.84). During the second CBF study, AVDO2 increased to 9.3 vol % (range 3.4-11) (P less than 0.05), and CMRO2 increased to 2.51 ml O2/100 g/min (range 1.88-3.00) P less than 0.05, while CBF was unchanged. The CO2 reactivity was present in all studies, median 1.8%/mmHg (range 0.5-15.1). The correlation coefficients between jugular venous oxygen tension/saturation, respectively, and CBF were high at tensions/saturations exceeding 4.0 kPa and 55%, indicating that hyperperfusion is easily unveiled by venous samples from the jugular vein during this anaesthesia.     

Computed tomography features immediately after replacement of haematoma with oxygen through percutaneous subdural tapping for the treatment of chronic subdural haematoma in adults

Summary In an effort to achieve a simple and less invasive method for the treatment of chronic subdural haematoma, replacement of the haematoma with oxygen by percutaneous subdural tapping was employed in 36 patients. This study was conducted on 23 haematomas in 20 patients, whose computed tomography (CT) scans immediately following the treatment were available for evaluation, with particular regard to distinguishing between their findings and those seen with tension pneumocephalus. The CT features werde divided into two patterns according to the location of oxygen; a convexity type (19 haematomas) and an interhemispheric type (4 haematomas). Analysis of the CT appearances revealed the oxygen was exclusively confined to the haematoma cavity, distinguishing it from the findings in tension pneumocephalus. This observation indicates the safety of replacement of the haematoma with oxygen when combined with our percutaneuous subdural tapping technique which prevents lesions of the inner haematoma membrane.     

Computer-Assisted Design of an Implantable, Intrathoracic Artificial Lung

Abstract: A semiempirical mathematical model of convective oxygen transport is used to design a new, low pressure loss, implantable artificial lung that could be used as a bridge to lung transplantation in patients with advanced respiratory failure. The mass transfer and flow friction relations pertinent to the design of a cross–flow hollow fiber membrane lung are described. The artificial lung is designed to transfer over 200 ml/min of oxygen at blood flow rates up to 5 L/min. A compact design and a blood-side pressure loss of <15 mm Hg allows the device to be implanted in the left chest without the need for a prosthetic blood pump. Surgical implantation of the artificial lung would require the creation of inflow and outflow anastomoses. Oxygen would be supplied via an external source. Blood properties, operating conditions, and empirically determined mass transfer and flow properties are all specified and input into a computer program that numerically solves the design equations. Computer–generated values for the device frontal area, blood path length, and fiber surface area are thereby obtained. The use of this computer–assisted design minimizes the need for extensive trial–and–error testing of prototype devices. Results from in vitro tests of a prototype implantable lung indicate that the mathematical model we describe is an accurate and useful tool in the design of hollow fiber artificial lungs.     

高压氧对家兔面神经撞击伤后面神经核内生长相关蛋白变化的影响(论著)

目的：研究面神经撞击伤后面神经核内生长相关蛋白（ＧＡＰ－４３）的变化及高压氧（ＨＢＯ）治疗的影响。方法：利用ＢＩＭ－Ⅱ型生物撞击机致家兔右侧面神经干损伤，应用ＳＰ免疫组化染色法观察损伤后１、３、７、１４和２１天（分别用ＨＢＯ治疗及不用ＨＢＯ为对照）面神经核内ＧＡＰ－４３的变化，并用电镜观察面神经干超微结构变化。结果：面神经损伤第１天，伤侧面神经核区ＧＡＰ－４３样免疫反应性神经元（ＧＬＩＮ）开始增多，第１４天其增多达到高峰，第２１天逐渐下降。ＨＢＯ治疗组伤后不同时期ＧＬＩＮ的增多明显高于对照组。伤后第２１天，与对照组相比ＨＢＯ组面神经干电镜观察可见较多的新生髓鞘。结论：ＨＢＯ治疗可使伤后面神经核内ＧＬＩＮ增多，因而有助于面神经损伤后的修复与再生。     

儿童最大吸氧量与体格发育关系的研究

本文报告了４３６名１０－１９岁男女儿童少年最大吸氧量与休格发育的关系。相关分析可见，ＶＯ２ｍａｘ，ＶＯ２ｍａｘ／身高及ＶＯ２ｍａｘ／最大心率与身高，体重及瘦体重等体格发育变量有高度正相关；ＶＯ２ｍａｘ／体重与各体格变量，男童呈较低的正相关，妇童为较低的负相关；ＶＯ２ｍａｘ／ＬＢＭ与各体格变量，男女童均无相关。按身高，体重及ＬＢＭ分组，将男女儿童分别为发育较好（第１）组及较差（第２）组，比较两组ＶＯ     

Physiological Effects of Mental Stress and Orthostasis in Young Insulin-Dependent Diabetic Patients

ABSTRACT. The effects of procedures which stimulate sympathetic activity, viz. mental stress induced by a colour-word conflict test (CWT) for 20 min, and orthostasis (ORT) for 8 min were studied in 8 young (16-20 yr) insulin-dependent diabetes mellitus (IDDM) patients and 9 age and sex-matched healthy controls. The IDDM patients showed no signs of neuropathy or retinopathy and their mean HbA_1c value was 8.4 ±0.6% (normal value < 5.0 %). Blood pressure and heart rate increased significantly during CWT and ORT in both groups. The changes in systolic blood pressure and heart rate were comparable in both groups during CWT; the IDDM group showed a higher ( p < 0.05) heart rate after 8 min of orthostasis, however. CWT and ORT elicited equivalent increases in noradrenaline in venous plasma in both groups ( p < 0.05), but the IDDM patients had 50% lower values ( p < 0.01) at rest, during CWT and at rest after CWT than controls. CWT and ORT evoked equivalent plasma adrenaline increases in both groups. The lipolysis marker, plasma glycerol, was about 40 % lower ( p < 0.05) in the IDDM group before and after CWT. Yet, mental stress evoked equivalent increases in glycerol levels ( p < 0.01) in both groups. These findings indicate that sympathetic activity in the young diabetic patients without signs of neuropathy may be blunted.     

Transhemation of bovine and human hemoglobin polymers in a simulated circulatory system

All-Union Hematology Research Center, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Vorob'ev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 11, pp. 500–501, November, 1991.