Rheological properties and function of blood cells in stored bank blood and salvaged blood

The technique involving filtration of diluted blood enables the separate analysis of the flow properties of different cell subpopulations. This study was designed to assess the changes occurring in the flow properties and function of blood cells in stored bank blood and salvaged blood compared to patient blood in a given clinical situation. We measured hydrogen peroxide production by neutrophils and the filterability, through 5 μm Nucleopore filters, of isolated red blood cells and of diluted blood. Samples were obtained from patients undergoing aortic surgery and blood intended for transfusion: either salvaged during surgery or stored bank blood. Both salvaged and bank blood were much less filterable than patient blood, with reduced deformability of both red and white blood cells. However, salvaged blood contained highly activated neutrophils with a prolonged transit time of the 'fast-flowing' cells in the analysis compared to bank blood. Bank blood contained significantly more particles which acted as pore-blockers. Cells in bank and salvaged blood therefore have markedly abnormal flow and biochemical properties compared to patient blood.     

The inhibition of TNF‐α‐induced leucocyte apoptosis by melatonin involves membrane receptor MT1/MT2 interaction

The pro‐apoptotic signalling cascades induced by tumour necrosis factor‐alpha (TNF‐α) have been intensively studied in multiple cellular systems. So far, it is known that TNF‐α can simultaneously activate survival and apoptotic cell death responses. The balance between these signals determines the ultimate response of the cell to TNF‐α. Moreover, emerging evidence suggests that melatonin may be involved in the protection of different cell types against apoptosis. Thus, the objective of this study was to evaluate the effect of melatonin on TNF‐α‐induced apoptosis in human leucocytes. Cells were treated with TNF‐α alone or in the presence of cycloheximide (CHX), which promotes caspase‐8 activation by eliminating the endogenous caspase‐8 inhibitor, c‐FLIP. Treatment with TNF‐α/CHX led to apoptotic cell death, as ascertained by annexin V/propidium iodide (PI) staining. Likewise, in the presence of CHX, TNF‐α stimulation produced cFLIP down‐regulation and subsequent caspase‐8 activation, thus directly triggering caspase‐3 activation and causing Bid truncation and subsequent caspase‐9 activation. Conversely, pre‐incubation of cells with melatonin inhibited TNF‐α‐/CHX‐evoked leucocyte apoptosis. Similarly, pretreatment of leucocytes with melatonin increased cFLIP protein levels, thereby preventing TNF‐α‐/CHX‐mediated caspase processing. Blockade of melatonin membrane receptor MT1/MT2 or extracellular signal‐regulated kinase (ERK) pathway with luzindole or PD98059, respectively, abolished the inhibitory effects of melatonin on leucocyte apoptosis evoked by TNF‐α/CHX. In conclusion, the model proposed by these findings is that the MT1/MT2 receptors, which are under the positive control of melatonin, trigger an ERK‐dependent signalling cascade that interferes with the anti‐apoptotic protein cFLIP modulating the cell life/death balance of human leucocytes.     

Leucocyte Subset Redistribution in a Human Model of Physical Stress

This study has investigated, under controlled conditions, peripheral mononuclear cells (PMNC) subset redistribution in a human experimental stress model consisting of cycloergometer activity in healthy male volunteers exposed to a stressful stimulus. After stressful stimuli, leucocyte subpopulations undergo a stereotyped redistribution peculiar for each PMNC cytotype. PMNC subpopulations involved to a greater extent were natural killer (NK) cells and lymphocytes T “memory” cells. The post-stress period was characterized by a decrease of the NK subpopulation. Our findings confirm the view of a sensible functional reduction of immunocompetence in stress conditions. This brings to the opening, even if for a short time, an “immunological window.”. This window remains open throughout the time of the stimulus, probably representing the basis of the progressive reduction of the competency of immune system. Catecholamines support the acute effects of stress influencing the anatomical redistribution of lymphocyte subpopulation and intermediating acute effects on PMNC. Cortisol, acting for longer time, contributes to create and maintain both the neutrocytosis and lymphopenia in the post-stress period following lymphocytosis.     

Operation-associated neutrophils in a percutaneous liver biopsy: effect of prior transjugular procedure

A young man with chronic active hepatitis was heavily sedated during an attempted transjugular liver biopsy. The procedure was abandoned after 3 h and an immediate percutaneous liver biopsy was performed. This showed features of chronic active hepatitis but, in addition, groups of polymorphonuclear leukocytes in the parenchyma. These were similar to the operation associated neutrophils encountered in liver biopsies taken during the course of abdominal surgery. In a review of 78 liver biopsies from patients with chronic active hepatitis, this type of infiltrate was seen in four of eight surgically resected specimens but not in 70 percutaneous biopsies. The neutrophilic infiltrate in the present case appears to be an unique occurrence in a percutaneous liver biopsy. It was probably related to hypoperfusion during the preceding prolonged sedation and illustrates the ease with which an already diseased liver can be further damaged.     

P-cresylsulphate, the main in vivo metabolite of p-cresol, activates leucocyte free radical production.

BACKGROUND: Chronic renal insufficiency is associated with the retention of solutes normally excreted by healthy kidneys. P-cresol, a prototype protein-bound uraemic retention solute, has been shown to exert toxic effects in vitro. Recently, however, it has been demonstrated that p-cresol in the human body is conjugated, with p-cresylsulphate as the main metabolite. METHODS: The present study evaluates the effect of p-cresylsulphate on the respiratory burst activity of leucocytes. RESULTS: P-cresylsulphate significantly increased the percentage of leucocytes displaying oxidative burst activity at baseline. Oxidative burst activity of stimulated leucocytes was however not affected. In contrast, p-cresol had no effect on the leucocytes at baseline, but inhibited leucocytes burst activity after stimulation. CONCLUSION: The present study demonstrates, for the first time, that p-cresylsulphate, the main in vivo metabolite of p-cresol, has a pro-inflammatory effect on unstimulated leucocytes. This effect could contribute to the propensity to vascular disease in the uraemic population.     

VASOCONSTRICTOR RESPONSES TO POLYMORPHONUCLEAR LEUCOCYTES FROM ATHEROSCLEROTIC RABBITS

1. The vascular contractile effects of polymorphonuclear leucocytes (PMN) isolated from control rabbits and from rabbits made atherosclerotic by 1% cholesterol feeding for 8 weeks were examined. 2. Rings of control rabbit thoracic aorta with or without endothelium were mounted at 2g tension in 10 mL organ baths and were submaximally contracted by phenylephrine (0.1 μmol/L). After 30 min incubation at 37° C, the supernatant of PMN (5X10⁷/mL, in Tyrode solution containing 0.25% bovine serum albumin) was obtained by centrifugation for addition to the vascular preparation. 3. Control PMN supernatant (443 μL) caused contraction (0.58±0.15g, n= 11) of phenylephrine-contracted aortic rings, which was prevented by removal of the endothelium (0.11 ± 0.07g, n= 5, P<0.05). However, the control PMN supernatant had no contractile effect on aortic rings at resting tension (0.00 ± 0.00g, n= 8). 4. By comparison, atherosclerotic PMN supernatant (443 μL) caused a significantly greater contraction of the aortic rings (1.41± 0.13g, n= 9, P<0.05 vs control PMN supernatant) that was only partly inhibited by removal of the endothelium (0.45 ± 0.20g, n= 9, P<0.05). Moreover, PMN supernatants from four of seven atherosclerotic rabbits contracted aortic rings at resting tension (3.5 ±1.4g, n= 7). 5. These results suggest that the release of a stable vasoconstrictor substance(s) by PMN is enhanced under conditions of atherosclerosis. The constrictor action of this substance(s) appears to be greater in the presence of a functional endothelium, and part of its action may involve inactivation of endothelium-derived nitric oxide.     

The pathogenesis of inflammatory disease: Surgical shock and multiple system organ failure

Chronic inflammatory disease, embracing rheumatoid arthritis (RA), inflammatory bowel disease (IBD), hepatitis, asthma, atherosclerosis, multiple system organ failure (MSOF), etc., is mediated by reactive oxygen species (ROS). These ROS originate from activated neutrophils in infections and in immune and autoimmune reactions, from tissue deposits of ferritin, and from futile cycling of cytochrome P450 (CYP) following exposure to persistent chemicals, and may be perpetuated by the actions of complement, cytokines and eicosanoids. Acute inflammation is normally arrested by removal of ROS by tissue glutathione (GSH) and the antioxidant vitamins, A, C and E, all of which are regenerated by NADH and NADPH. Failure of this antioxidant defence system can lead to oxidative stress and to chronic inflammatory disease, including surgical shock and MSOF. The roles of oxidative stress and microcirculatory arrest in promoting MSOF, and of GSH, the antioxidant defence system, and fibronectin in preventing this, are reviewed in the light of recent experimental studies of surgical shock, including fasting, anaesthesia, hepatic ischaemia and reperfusion.     

聚合酶链反应技术检测儿童肺结核效果初探

目的 评价聚合酶链反应（polymerase chain reaction,PCR)技术在儿童结核中的检测效果。方法 应用PCR技术同时检测106例可疑儿童肺结核胃抽出液和外周血白细胞标本中的结核杆菌DNA（TB－DNA0，比较两种方法在临床上对儿童肺结核病诊断的应用价值。结果 对PCR技术检测儿童肺结核胃抽出液和外周血白细胞检出率进行了比较，胃抽出液检出率为45.0%，外周血白细胞检出率为75.0%。结论 用PCR技术检测外周血白细胞，可能是临床儿童肺结核的一种较好的诊断，而胃抽出液PCR检测不仅会使儿童带来痛苦，而且诊断价值有限。     

Local immune responses in sensitized sheep following challenge infection with Teladorsagia circumcincta

Sheep were sensitized by weekly infections with Teladorsagia circumcincta over a 9-week period. After a 12-week rest, sheep were divided into four groups and killed without challenge or 3, 5 and 10 days post challenge (DPC) with 50000 L3. Recovery of challenge larvae from abomasal scrapings was highest at 3 DPC while no parasites were recovered by 10 DPC. Abomasal lymph nodes (ALN) of challenged sheep were significantly larger at 5 DPC, coinciding with an increase in the proportion of CD4 T cells and a decrease in CD21+ cells, probably reflecting the loss of CD21 from terminally differentiated antibody secreting cells. A significant increase was observed in gammadelta-TCR+ cells at 3 DPC in the ALN, while their number slightly decreased in the abomasal tissues throughout the challenge period. The number of tissue eosinophils was dramatically increased after challenge compared with the unchallenged controls, with a peak at 3 DPC, coinciding with the peak in larval recovery. CD4+ cells significantly increased in the abomasal tissues at 5 DPC, while no changes in globule leucocytes were observed until 10 DPC. Antibody-secreting cell probes (ASC-probes) generated from the ALN showed highest reactivity against larval antigens at 5 DPC. This reactivity was predominantly directed against regions between 90 and 100 kDa and 30-35 kDa in the L3 preparation and lower molecular weight antigens in the L4. No reactivity was observed against the adult extract. The 30-35 kDa antigen seemed to exist as a high molecular weight complex in L3 homogenate and was not susceptible to protease K treatment, suggesting it may be non-protein in nature.     

Leucocyte subpopulations in the seminal plasma and their effects on fertilisation rates in an IVF cycle

Controversy exists on the role of leucocytospermia on fertilisation rates and IVF outcomes. The aim of our study was to identify the effect of leucocytes and leucocyte subpopulations on fertilisation rates in an IVF cycle. A prospective comparative study of the leucocyte subpopulations of seminal fluid of partners of women attending an IVF cycle was conducted. The samples underwent immunocytochemical staining. The monoclonal antibodies used in this study include CD3, CD4, CD8 (T Cells), CD14 (monocytes/macrophages), CD16 (granulocytes), CD20 (B Cells), CD45 (Pan Leucocytes), CD56 (natural killer cells) and CD69 (activated T and B Cells). Of 21 patients who were recruited into the study, seven were identified as poor fertilisers (<35%) and 14 were identified as good fertilisers (>60%). Data were analysed with SPSS version 14. The total leucocyte counts (CD45) between the poor and good fertilisers were not statistically significant. The macrophages and the monocytes (CD14) were significantly elevated in the good fertilisers group in comparison with the poor fertilisers (P < 0.05). We also found that T cells (CD2, CD4, CD8) and CD14 (macrophages) correlated significantly (r = 0.47, P value < 0.01) with the fertilisation rate. Our study confirms that the presence of leucocytes does not adversely affect the fertilisation rates and the outcome of an IVF cycle. However, macrophages and the monocytes (CD14) were significantly elevated in the good fertilisers group. The increased phagocytic activity in these individuals might increase their fertilising potential by removing spermatozoa with abnormal morphology.