Behavioral conditioning of endotoxin-induced plasma iron alterations

The cascade of physiologic mechanisms in response to infection, the acute-phase response, is recognized as playing a major role in host defence. One such response is the hypoferremia that is consistently reported to occur during bacterial infection. This study aimed to determine whether the alterations in plasma iron were conditionable using the conditioned taste aversion (CTA) paradigm. The regime involved the pairing of a novel-tasting saccharin solution with bacterial endotoxin. Seven days after the initial pairing of these stimuli (the test day), the saccharin solution was represented. Animals exposed to this condition displayed a significant reduction in the level of plasma iron. Animals treated with an intraperitoneal dose of 400 μg/Kg lipopolysaccharide (LPS) displayed lower conditioned iron levels than rats infused with 100 μg/Kg LPS; however, this difference was not significant. These results showed that in addition to other acute-phase responses (fever and anorexia), plasma iron alterations are able to be manipulated through behavioral manipulations.     

饮用水中过量铁和锰对蚕豆根尖细胞微核率的影响

目的 探讨饮用水中过量的铁和锰的致突变作用。方法 采用蚕豆根尖细胞微核技术。结果 当水中铁含量超过饮用水卫生标准3～10倍时，蚕豆根尖细胞微核率升高，且微核率与铁剂量间存在着明显的剂量-反应关系。锰对蚕豆根尖细胞微核率升高的作用不明显，只有在剂量高达卫生标准1000倍时，才会使蚕豆根尖细胞微核率有所增加。结论 过量的铁有致突变作用。     

Nutritional Anemias

Prevention of nutritional deficiencies should be attained by the consumption of a good diet. Unfortunately, in the case of iron, this is not always possible, and it is advantageous to fortify food with iron. Milk-based formulas and cereals are the most commonly used iron-fortified products in infancy and early childhood. Bioavailability of iron from cereals is low and more clinical studies on the field are necessary to demonstrate the effectiveness of iron-fortified cereals in infants and children of developing countries. Infections and excessive blood loss in infancy related to the use of fresh, pasteurized or powdered cow milk result in much of the anemia we currently see in industrialized countries. Vitamin A deficiency interacts with iron metabolism and recent intervention studies have shown that anemia in Vitamin A deficient children can be successfully treated with oral supplements.     

An alternative method of nitrous oxide delivery into a minimal-flow circle breathing system

We have sought to define a way in which nitrous oxide can be safely and universally used at minimal to low flows by utilising a circle system with a controlled leak provided by a standard gas analyser sampling line and a fresh gas supply of 50% nitrous oxide in oxygen, entering from a trunk interposed between the ventilator and the circle system. Although preliminary calculations suggested that this arrangement was likely to work, it was found that 13 of 23 patients studied prospectively developed an inspired oxygen fraction below 0.3. We conclude that, although this arrangement provides a new means of introducing nitrous oxide into the circle breathing system, it does not appear inherently safer or more convenient than the conventional route.     

Isoflurane for removal of chest drains after cardiac surgery

Thirty-five patients who had undergone uncomplicated cardiac surgery were randomly allocated to receive either Entonox or isoflurane 0.25% in Entonox as inhalational analgesia for the removal of their two chest drains. The gases were presented premixed in high-pressure cylinders and were self-administered by means of a demand valve. The removal of the second drain was more painful than the first but that pain was better controlled by isoflurane 0.25% in Entonox than by Entonox alone.     

A porcine model for sequential assessments of cerebral haemodynamics and metabolism

We present a physiologically stable porcine model designed for sequential assessments of pharmacological effects on mean hemispheric cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) at sustained normocapnia. The dynamic influence of continuously administered fentanyl (0.040 mg.kg-1.h-1 i.v.), nitrous oxide (70%) and pancuronium (0.30 mg.kg-1.h-1 i.v.) on these variables was studied in eight normoventilated pigs. CBF was reliably assessable at 10-min intervals by clearance of intra-arterially injected 133Xe, monitored by an extracranial scintillation detector. CMRO2 was calculated from CBF and the simultaneously measured cerebral arteriovenous difference in blood oxygen content. The intracerebral distribution of a contrast medium injected into the external and internal carotid arteries was studied by angiography, and the cerebral venous outflow was investigated by measurements of the distribution of an intra-arterially administered non-diffusible tracer, [99mTc]pertechnetate, to the internal and external jugular veins. After a 3-h equilibration period, CBF and CMRO2 were determined on six occasions over a study period lasting 1 h 40 min. The mean ranges of these variables were 56-60 and 1.9-2.0 ml.100 g-1.min-1, respectively. We conclude that the model enables repeated assessments of CBF and CMRO2 under stable physiological background conditions and thus valid cerebral pharmacodynamic investigations of drugs given for anaesthesia.     

阻塞性黄疸患者并发肾功能损害时血清一氧化氮的变化及其临床意义

目的　探讨阻塞性黄疸患者并发肾功能损害时血清一氧化氮 (NO)的变化及其临床意义。方法　对 2 5例阻塞性黄疸并发肾功能损害患者的血清NO、一氧化氮合成酶 (NOS)活性、BUN和Cr值进行检测 ,并以 2 6例健康者作为正常对照。结果　阻塞性黄疸组BUN和Cr高于正常对照组 (P<0 .0 1 ) ,而NO和NOS则低于正常对照组 (P<0 .0 1 )。相关分析显示 ,NO与BUN和Cr呈负相关关系 ,其相关系数分别为 - 0 .41 9和 - 0 .553(P<0 .0 1 )。结论　阻塞性黄疸并发肾功能损害时其血清NO和NOS下降 ,提示NO在阻塞性黄疸时对肾功能有一定保护作用     

The effect of 2,4-diamino-6-hydroxy-pyrimidine on postburn Staphylococcus aureus sepsis in rats

GTP-cyclohydrolase I (GTP-CHI) is the first and rate-limiting enzyme for the de novo biosynthesis of biopterin. The present study was to observe the effect of 2,4-diamino-6-hydroxy-pyrimidine (DAHP),an inhibtor of GTP-CHI, on the development of postburn Staphylococcus aureus sepsis. Methods: 56 male Wistar rats were randomly divided into four groups as follows: normal control group (n= 10), scald control group(n= 10),pos tburn sepsis group (n= 20) and DA HP treatment group (n= 16). In the scald control group, rats were subjected to a 20% total body surface area (TBSA) Ⅲ° scald injury, then sacrificed at 24 hrs. In the postburn sepsis group (n=20), rats were inflicted with 20% TBSA Ⅲ° scald followed by Staphylococcus aureus challenge, and they were further divided into 2 and 6 hrs groups. In the DAHP treatment group (n= 16), animals were intraperitoneally injected with a dose of 1g/kg DAHP prior to Staphylococcus aureus challenge, and then further divided into 2, 6 hrs groups. Tissue samples from liver, kidneys, lungs and heart were collected to determine GTP-CHI, inducible nitric oxide synthase (iNOS) and tumor necrosis factor-α (TNF-α) mRNA expression. Meanwhile, biopterin and nitric oxide (NO) levels in these tissues were also measured. Results: After the scald injury followed by Staphylococcus aureus challenge, GTP-CHI mRNA expression and biopterin levels significantly elevated in various tissues such as liver, heart, kidneys and lungs, so did the values of iNOS mRNA expression and NO formation (P＜0.01). Pretreatment with DAHP could significantly reduce GTP-CHI/biopterin induction (P＜0. 05～0. 01), and the up-regulation of iNOS/NO was also suppressed. Furthermore, DAHP administration could also inhibit the gene expression of TNF-α. 2 hrs after septic challenge, TNF-α mRNA expression in liver, kidneys and lungs in DAHP-treated group were 35.7%, 37.3% and 33.0% of those in postburn septic group, respectively. Additionally, in animals without DAHP treatment, the 6-hour mortality was 55.6% (20/36), while it was only 25.0% in DAHP-treated animals (4/16, P=0. 08). Conclusions: Early treatment with DAHP might be a potential strategy to prevent the development of postburn Staphylococcal sepsis, which appears to be associated with down-regulation of biopterin and NO formation by DAHP.     

变应性鼻炎患者血清一氧化氮水平变化及临床意义

目的 :通过 5 6例变应性鼻炎患者血清一氧化氮 (NO)浓度的观察 ,研究内源性NO水平的变化与变应性鼻炎病理过程的关系及其临床意义。方法 :血清NO水平采用硝酸还原酶比色法测定。结果 :变应性鼻炎组血清NO水平显著高于正常对照组 (q =2 7.2 3,P <0 .0 1)及慢性鼻炎组 (q =15 .2 3,P<0 .0 1)。慢性鼻炎组与正常对照组血清NO浓度差异无显著性 (q =1.89,P >0 .0 5 )。结论 :变应性鼻炎患者血清中NO水平显著高于正常对照组及慢性鼻炎组 ,提示NO在变应性鼻炎的发病过程中可能起重要作用 ,对其机理的研究为变应性鼻炎的治疗提供新的方法。