探讨血小板计数在血泵离体实验中的意义

为了探讨血小板计数在血泵离体实验中的意义。我们用两种滚压泵分成两组，作5对16小时离体长时间转流实验，血样本为转前作对照组、转流4h后每隔2h抽1次。测定项目：血小板计数、游离血红蛋白。结果：两组血小板计数值均随转流时间延长而呈线性逐渐增加，各时点值与前时点比（P＜0．05），有显著差异，两组游离血红蛋白量也随转流时间延长而呈线性增加。血小板计数与游离血红蛋白呈直线回归相关关系。结论；在血泵离体转流实验中，血小板计数可反映血细胞碎片的数量，因此可作为一项评价血泵离体溶血性能的客观指标。     

Cytokines induce selective granulocyte chemotactic responses

Neutrophils, eosinophils and cytokines are important in allergic airway inflammatory responses. However, it is unclear how cytokines selectively influence neutrophils versus eosinophils to migrate to an inflammatory site. The cytokines, transforming growth factor-1 (TGF-1), interleukin (IL)-1, IL-5, IL-8, granulocyte macrophage-colony stimulating factor (GM-CSF) and tumor necrosis factor- (TNF-), are released subsequent to allergic reactions and affect both neutrophil and eosinophil functions. We studied whether these cytokines differed in capacity to induce human neutrophil versus eosinophil migration through naked filters and human umbilical vein endothelial cell (HUVEC) and human pulmonary type II-like epithelial (A549) cell monolayers grown on filters. Dose-response experiments using all barriers were performed for each granulocyte and cytokine. TGF-1 did not induce granulocyte migration. IL-5 induced eosinophil migration only through naked filters. IL-1 stimulated neutrophil migration through cellular barriers, but not through naked filters. TNF- and GMCSF induced neutrophil and eosinophil migration through filters, but only neutrophil migration through cellular monolayers. Only IL-8 induced significant neutrophil and eosinophil migration; however, there were clear-cut differences between the neutrophilotactic and eosinophilotactic responses through all barriers emploved. Thus, our data show that these cytokines induce distinct chemotactic responses for neutrophils versus eosinophils. Moreover, by using relevant cellular barriers versus naked filters, our data better examines the capability of these cytokines to induce selective granulocyte migration to an inflammatory site in lung diseases such as asthma.accepted by G. W. Carter     

The effect of exhaustive exercise on the antioxidant enzyme system in skeletal muscle from calcium-deficient rats

 The aim of the current study was to elucidate the synergism of dietary calcium restriction and exhaustive exercise in the antioxidant enzyme system of rat soleus muscle, and to investigate the involvement of neutrophils in exercise-induced muscle damage. Forty-eight male Wistar rats were assigned to the following groups: control (C) or calcium-restricted [1 month (1 M) or 3 months (3 M)]. Each group was subdivided into acutely exercised or non-exercised groups. Soleus muscle from each rat was analysed to determine the levels of antioxidant enzymes [Mn-superoxide dismutase (SOD), Cu,Zn-SOD, glutathione peroxidase (GPX), and catalase (CAT)]. Dietary calcium restriction resulted in calcium deficiency and upregulated the antioxidant enzymes examined except GPX. Conversely, exhaustive exercise significantly decreased GPX and CAT, but not SODs activities in the calcium-restricted (1 M and/or 3 M) rats. Contents of immunoreactive Mn-SOD and Cu,Zn-SOD were only increased in the 3 M rats. During calcium restriction, the mRNA expression of both forms of SOD showed initial upregulation, followed by downregulation. Exhaustive exercise significantly increased the mRNA expressions only in the 3 M rats. Moreover, exhaustive exercise markedly increased myeloperoxidase activity in soleus muscles from the 1 M and 3 M rats compared with the C rats, and significantly enhanced the ability of neutrophils to generate superoxide in the 3 M rats. The results demonstrate that dietary calcium restriction upregulates certain antioxidant enzyme activities in rat soleus muscle, indicating an enhanced resistance to potential increases in intracellular reactive oxygen species. The results also suggest that exhaustive exercise may cause oxidative damage in soleus muscle of calcium-deficient rats through the activation of neutrophils. Received: 4 August 1997 / Received after revision: 29 September 1997 / Accepted: 26 November 1997     

Rapid non-genomic inhibitory effects of glucocorticoids on human neutrophil degranulation

Background: Glucocorticoids acting as anti-inflammatory or immunosuppressive drugs have been shown to exert most of their effects genomically. Recent findings suggest that non-genomic activity might be relatively more important in mediating the therapeutic effects of high-dose pulsed glucocorticoid. However, few non-genomic anti-inflammatory effects were reported, much less non-genomic mechanisms.Objective: This study was performed to investigate the nongenomic effects of glucocorticoids on human neutrophil degranulation.Methods: Purified human neutrophils were pretreated with 6 -methylprednisolone or hydrocortisone for 5 min, and then primed with N-formyl-methionyl-leucyl-phenylalanine (fMLP) (10^–6 M) or phorbol myristate acetate (PMA) (50 ng/ml) in the presence of cytochalasin B. The release of two markers of neutrophil granules, lactoferrin and myeloperoxidase, was measured by ELISA and enzymology methods respectively.Results: Both 6 -methylprednisolone (10^–5–10^–4 M) and hydrocortisone (10^–4 M) showed significant inhibitory effects on neutrophil degranulation within 5 min after fMLP administration. For PMA stimulated degranulation, 6 -methylprednisolone (10^–4 M) showed significant inhibitory effects (p < 0.01), while hydrocortisone (10^–4 M) only showed an inhibitory tendency (P > 0.05). Neither RU486 (10^–5 M) nor cycloheximide (10^–4 M) could alter the inhibitory effects of glucocorticoids.Conclusion: Our results demonstrate that megadoses of glucocorticoids exert rapid inhibitory effects on human neutrophil degranulation at the cellular level via a new mechanism that is independent of corticosteroid type II receptor occupation or protein synthesis. We infer that these effects may be very important when glucocorticoids act as anti-inflammatory drugs during pulse therapy.Received 20 May 2004; returned for revision 21 July 2004; accepted by M.J. Parnham 23 September 2004L. Liu and Y. X. Wang contributed equally to this work.     

Shielding Effect of Mineral Schungite during Electromagnetic Irradiation of Rats

We studied the effect of nonthermal 37-GHz radiation on hemopoiesis in schungite-shielded Wistar rats. Radiation with right-handed or left-handed rotation of the polarization plane of electromagnetic wave was used. Shielding with schungite decreased the severity of damage produced by high-frequency electromagnetic radiation.     

Increased migration of neutrophils to granulocyte-colony stimulating factor in rat carrageenin-induced pleurisy: Roles of complement,bradykinin, and inducible cyclooxygenase-2

Administration of human recombinant granulocyte colony-stimulating factor (G-CSF, 100 g/kg/day, s.c) to rats for 4 days significantly increased circulating neutrophil counts (by 1130%), together with an increase in mononuclear leukocyte counts (by 119%). Infiltrated pleural neutrophil counts in G-CSF-treated rats (G-CSF-r) 5h after the intrapleural injection of zymosanactivated serum were significantly higher (by 155%) than those in control rats (Vehicle-r). In carrageenin-induced pleurisy, counts of infiltrated pleural neutrophils in G-CSF-r 5 and 7h after carrageenin were significantly higher (by 119% and 116%) than those in Vehicle-r. G-CSF treatment increased the volume of pleural exudate and the plasma exudation rate by 122% and 226%, compared to values in Vehicle-r 5h after carrageenin. Cobra venom factor (75 g/kg, i.v.) significantly reduced pleural neutrophil migration in G-CSF-r (by 53%) and Vehicle-r (by 49%). Bromelain (10 mg/kg, i.v.) and aspirin (100 mg/kg, p.o.) reduced pleural neutrophil migration and reduced exudate volume and plasma exudation. Intrapleural bradykinin-(1–5) and prostaglandin E₂ levels were significantly higher in G-CSF-r than in Vehicle-r. The increased neutrophil migration in G-CSF-r may be atributed to enhanced activation of the complement system facilitated by increased plasma exudation due to bradykinin and prostaglandins.accepted by M. J. Parnham     

Mobilization and oxidative burst of neutrophils are influenced by carbohydrate supplementation during prolonged cycling in humans

Prolonged, strenuous exercise may lead to suppressive effects on the immune system, which might be responsible for a greater susceptibility to opportunistic infections. The aim of this study was to examine the influence of carbohydrate substitution (CHS) during prolonged, strenuous exercise on neutrophil granulocytes and their oxidative burst (intracellular oxidation of dihydrorhodamine₁₂₃ to rhodamine₁₂₃ after induction by formylized 1-methionyl-1-leucyl-1-phenylalanin) using flow cytometry. In three trials different concentrations of CHS (placebo compared to 6% and 12% CHS; 50 ml·kg^–1) were given randomly to 14 endurance trained cyclists [mean (SD) age 25 (5) years, maximal oxygen uptake 67 (6) ml·min^–1·kg^–1] cycling for 4 h in a steady state at 70% of their individual anaerobic threshold. Blood samples were taken before, immediately after cessation, 1 h and 19 h after exercise. A significant rise in neutrophil counts was observed immediately after cessation and 1 h after exercise with a return to normal rest values 19 h after exercise for all three conditions (P<0.001). The relative proportions of rhodamine₁₂₃+ neutrophils were significantly diminished in all three conditions 1 h after exercise (P<0.01), while the mean fluorescence intensity was lowest in the placebo trial and differed significantly to the 12% CHS trial (P=0.024) and almost significantly to the 6% CHS trial (P=0.052). In conclusion, these data suggest a beneficial effect of CHS on the neutrophil oxidative burst and a possible attenuation of the susceptibility to infections, presumably due to the reduction of metabolic stress in prolonged, strenuous exercise. Electronic Publication     

Hemoglobin levels in Tibet: different effect of age and gender for Tibetans vs Han

Tibetans form a population which has resided on the Qinghai–Tibetan plateau for thousands of years, and are reported to have less hemoglobin than Han Chinese lowlanders who have migrated to the plateau. However, for various altitudes, detailed comparisons of hemoglobin in the two ethnic groups has not been reported. We investigated the hypothesis that the effects of altitude, age, and gender on hemoglobin concentration would differ between Han and Tibetan residents of the plateau. Hematological parameters for both genders were determined in healthy Tibetan adults (n=3,000) and children (n=332), and healthy Han Chinese adults (n=2,612) and children (n=275), aged 5–60 years living at four different altitudes (mean altitude of 2,664, 3,813, 4,525, and 5,200 m). Hemoglobin values increased with altitude for all ages in both ethnic groups and in both genders. The gain in hemoglobin with altitude had the rank order: Han males > Han females > Tibetan males and females. Even before puberty, Han children had more hemoglobin than Tibetan children. An effect of age on hemoglobin was seen at the time of puberty in men, but not in women. A positive correlation was found between hemoglobin concentration and age in adult Han males and females, but not in Tibetan males, and only at the higher altitudes, in Tibetan females. In both Tibetans and Hans, males had higher hemoglobin values than females at each altitude, but the gender differences increased with altitude in Han, whereas it either decreased or did not change in Tibetans. Examination of hemoglobin levels by histogram showed non-Gaussian distributions: Tibetan men and women had skewing to higher values, whereas Han men and women had skewing in the opposite direction. We conclude that increasing age and the effect of gender in Tibetans are associated with different hemoglobin responses to altitude than in Han, and we speculate that genetic influences may be involved.     

Total lymphocyte count of 1200 is not a sensitive predictor of CD4 lymphocyte count among patients with HIV disease in Kampala, Uganda

Introduction

Total Lymphocyte Count (TLC) has been found to be an inexpensive and useful marker for staging disease, predicting progression to AIDS and death and monitoring response to ART. However, the correlation between TLC and CD4 has not been consistent. Access to HAART is expanding in Kampala, Uganda, yet there are no published data evaluating the utility of TLC as inexpensive surrogate marker of CD4 cell count to help guide therapeutic decisions.

Objective

To evaluate clinical illnesses and total lymphocyte count (TLC) as surrogate markers of the CD4 cell count in HIV infected persons being considered for ART.

Methods

A total of 131 patients were enrolled and evaluated by clinical assessment, TLC and CD4 count. Clinical illnesses and TLC dichotomized at various cut-point values were used to determine the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) for the diagnosis of CD4 count <200 cells/mm³ among 100 participants fulfilling criteria for WHO clinical stage 2 and 3.

Results

A strong correlation was observed between TLC and CD4 (r = 0.73, p<0.0001). For all clinical syndromes, except pulmonary tuberculosis, the positive predictive values (PPV) for a CD4 count <200 cells/mm³ were high (>80%) but the negative predictive values (NPV) were low. Using the WHO recommended TLC cut-off of 1200 cells/mm³ to diagnose a CD4 less than 200 cells/mm³, the PPV was 100%, and the NPV was 32%.

Conclusion

Our data showed a good correlation between TLC and CD4 cell count. However, the WHO recommended TLC cutoff of 1200 did not identify the majority of WHO stage 2 and 3 patients with CD4 counts less than 200 cells/mm³. A more rational use of TLC counts is to treat all patients with WHO stage 2 and 3 who have a TLC <1200 and to limit CD4 counts to patients who are symptomatic but have TLC of >1200.     

Control of fluid shear response in circulating leukocytes by integrins

Recent evidence shows that circulating leukocytes respond not only to humoral inflammatory mediators but also to fluid stresses. Application of fluid shear stress (of the order of 1–10 cm² to fresh migrating leukocytes leads to initial retraction of pseudopods, an important step to facilitate normal passage of leukocytes through the microcirculation and to prevent spreading on the endothelium. The ability to respond to fluid shear stress, however, may be regulated under different physiological conditions. In the current study, we examine the role of integrins in the fluid shear response as measured by pseudopod retraction with the use of antibodies against human neutrophil ₁ and ₂ integrins. Neutrophils adhering via ₂ integrins exhibit normal ability to project pseudopods and to migrate. Such cells show normal response to fluid shear with rapid pseudopod retraction. In contrast, attachment via ₁ integrins leads to firmly adhesive leukocytes, spreading and almost no cell migration. Such leukocytes exhibit a significantly attenuated ability for pseudopod retraction under fluid shear. These results suggest that integrins may serve as a regulating mechanism for fluid shear response in human leukocytes. Attachment via ₁ integrins may lead to an abolishment of the fluid shear response. © 2002 Biomedical Engineering Society. PAC2002: 8716-b, 8719Tt