Effect of thrombopoietin and granulocyte colony-stimulating factor on platelets and polymorphonuclear leukocytes

Thrombopoietin (TPO) and granulocyte colony-stimulating factor (G-CSF) may be administered together in aplastic patients. We evaluated the effect of both cytokines alone or combined on platelets and polymorphonuclear leukocytes (PMN) functional responses. TPO, G-CSF, or the combination of both cytokines, induced neither platelet nor PMN activation. TPO but not G-CSF synergized with threshold ADP concentrations to induce maximal aggregation and ATP release. The synergistic effect of TPO with ADP was not modified by the presence of G-CSF. Flow cytometry studies have shown that thrombin-induced loss of GPIb from platelet surface was significantly increased by pretreatment of platelets with TPO, G-CSF, or both cytokines. P-selectin expression induced by thrombin was augmented by TPO, but not by G-CSF. Coincubation of the cells with TPO and G-CSF did not modify the values obtained with TPO alone. Expression of CD11b on PMN surface was augmented by G-CSF or fMLP. G-CSF-treated PMN increased the effect of fMLP on CD11b expression. TPO did not modify either basal levels of CD11b or the increased expression induced by G-CSF or fMLP. Incubation of PMN with both cytokines showed no differences compared to G-CSF alone. Platelet-PMN aggregates induced by thrombin in whole blood were augmented by TPO. G-CSF alone neither synergized with thrombin nor changed the results observed with TPO. These data show that in vitro functional responses of platelets, or PMN induced by TPO or G-CSF alone, were neither further increased nor inhibited by treatment of the cells with both cytokines.     

Atherosclerosis potentiates constrictor responses of cerebral and ocular blood vessels to thromboxane in monkeys

The goal of our study was to examine the effects of infusion of serotonin and the thromboxane A2 analogue U46619 into one carotid artery to stimulate their release from platelets during aggregation. We measured blood flow to the brain and eye using microspheres and cerebral microvascular pressure in the pial arteries of normal and atherosclerotic cynomolgus monkeys. Unilateral intracarotid infusion of 10-30 micrograms/min serotonin did not affect cerebral blood flow in normal or atherosclerotic monkeys; serotonin did not alter blood flow to the eye in normal monkeys but decreased flow to the retina and choroid in atherosclerotic monkeys by 39 +/- 11% and 44 +/- 10% (mean +/- SEM), respectively. Infusion of 30 ng/min U46619 did not alter cerebral blood flow but increased the pressure gradient from the aorta to the pial artery, which is an index of large-artery resistance, in atherosclerotic monkeys. U46619 had no effect on blood flow to the eye in normal monkeys but decreased blood flow to the retina and choroid by 71 +/- 14% and 53 +/- 13%, respectively, in atherosclerotic monkeys. Thus, atherosclerosis potentiates the constrictor responses of large cerebral arteries to thromboxane and the responses of blood vessels of the eye to thromboxane and serotonin.     

Effects of nicardipine on cerebral vascular responses to hypocapnia and blood flow velocity in the middle cerebral artery

We noninvasively evaluated the effects of nicardipine on cerebral vascular responses to hypocapnia and blood flow velocity in the middle cerebral artery of 10 patients aged 17-60 (mean +/- SD 46.1 +/- 11.8) years. During fentanyl/diazepam/nitrous oxide anesthesia, mean blood flow velocity in the middle cerebral artery was measured and cerebral vascular reactivity to hypocapnia induced by hyperventilation was assessed before and during the administration of nicardipine. Mean blood flow velocity was measured using transcranial Doppler ultrasonography, and the cerebral vascular reactivity was expressed as the percentage change in mean blood flow velocity per unit change in end-tidal PCO2. During the administration of 5.1 +/- 1.3 micrograms/kg/min nicardipine, which caused a 26% reduction in mean arterial blood pressure, mean blood flow velocity increased significantly from 57.2 +/- 19.2 to 64.2 +/- 21.6 cm/sec (p less than 0.01, paired t test), whereas cerebral vascular reactivity showed no significant change (4.0 +/- 1.2% and 4.9 +/- 2.5%, respectively). In conclusion, during fentanyl/diazepam/nitrous oxide anesthesia in patients, cerebral vascular reactivity to hypocapnia was maintained and nicardipine-induced hypotension resulted in increased middle cerebral artery blood flow velocity with maintenance of carbon dioxide reactivity to hypocapnia.     

脑出血患者急性期血小板活化的临床意义

目的探讨脑出血(ICH)急性期血小板活化的临床意义。方法33例行微创手术的ICH患者,术前经头颅CT测量血肿周围脑水肿带的大小,术中留取血肿液及静脉血,用流式细胞术(FCM)检测其血小板表面糖蛋白P-选择素(CD62p)和血小板膜凝血酶敏感蛋白(TSP)的表达,并与所测水肿带大小进行相关性分析。结果CD62p、TSP在ICH组的表达显著高于健康对照组,ICH组血肿液中其表达量显著高于静脉血中的表达;血肿液中血小板CD62p、TSP的表达与血肿周围脑水肿程度呈显著正相关(r=0.4781,r=0.5183,均P<0.005);静脉血中血小板CD62p、TSP表达量与血肿周围脑水肿程度呈显著正相关(r=0.4058,r=0.4193,均P<0.05),前者比后者相关性更为显著。结论ICH急性期血小板活化,活化的血小板可能参与了血肿周围脑水肿的形成。     

老龄大鼠慢性脑灌注不足脑内白细胞和T细胞的入侵

目的 探讨白细胞和Ｔ细胞在慢性脑灌注不足脑损害中的活动。方法 ７０只老龄Ｗｉｓｔａｒ大鼠持久性双侧颈总动脉结扎（２ＶＯ）,其中１２只接受环孢霉素Ａ（ＣｓＡ）治疗。免疫组化法检测白细胞和Ｔ细胞。实现研究为持久性２Ｖ０１～４月。结果 大鼠慢性脑灌注不足造成了明显的脑损害与白细胞和Ｔ细胞的入侵。１～４月,白细胞在皮层、白质和海马的活动均减少,而Ｔ细胞的活动在皮层下白质增多,在皮层和海马减少。同时脑损害加重。ＣｓＡ治疗后白细胞和Ｔ细胞的活动明显减弱,脑损害减轻。结论 慢性脑灌注不足的病理损害,尤其白质损害中,Ｔ细胞伴有重要作用,白细胞仅起次要作用。ＣｓＡ能抑制白细胞和Ｔ细胞的活动,从而防治了脑损害。     

Circulating platelets show increased activation in patients with acute cerebral ischemia

Platelet activation plays a central role in acute arterial stenosis as has been shown in coronary heart disease. Likewise it can be assumed to be of importance in the evolution of acute cerebral ischemia (ACI), particularly in patients with large vessel disease. Flow cytometric detection of platelet adhesion molecules as a marker of platelet activation in a group of patients with ACI and different etiologies has not been evaluated. In 72 patients with ACI and 72 controls, the exposure of activation-dependent adhesion molecules was determined using flow cytometry after immunostaining with monoclonal antibodies against CD 62, CD 63 and thrombospondin. The extent of platelet activation differed as a function of the etiology of ACI: platelets from patients with atherosclerosis of brain-supplying arteries expressed significantly more activation markers than did controls, whereas patients with cardioembolic stroke did not. By analyzing platelet adhesion molecules it is possible to describe platelet activation profiles in patients with acute cerebral ischemia. This diagnostic procedure will be useful for monitoring individualized anti-platelet therapy and may enable distinguishing different subgroups of stroke patients.     

高血压对大鼠脑缺血区白细胞浸润及梗死体积的影响

目的观察高血压这一中风危险因素对脑缺血区白细胞浸润及梗死体积的影响。方法采用大鼠肾性高血压模型及MCA闭塞／再通模型,测定正常血压大鼠及高血压大鼠脑缺血区的MPO活性及梗死体积百分比。结果高血压大鼠循环血白细胞总数、脑缺血区MPO活性及梗死体积百分比分别为23．73±4．32×109／L、3．4     

Impaired cerebral vascular and metabolic responses to parametric N-back tasks in subjective cognitive decline

Previous studies reported abnormally increased and/or decreased blood oxygen level-dependent (BOLD) activations during functional tasks in subjective cognitive decline (SCD). The neurophysiological basis underlying these functional aberrations remains debated. This study aims to investigate vascular and metabolic responses and their dependence on cognitive processing loads during functional tasks in SCD. Twenty-one SCD and 18 control subjects performed parametric N-back working-memory tasks during MRI scans. Task-evoked percentage changes (denoted as δ) in cerebral blood volume (δCBV), cerebral blood flow (δCBF), BOLD signal (δBOLD) and cerebral metabolic rate of oxygen (δCMRO₂) were evaluated. In the frontal lobe, trends of decreased δCBV, δCBF and δCMRO₂ and increased δBOLD were observed in SCD compared with control subjects under lower loads, and these trends increased to significant differences under the 3-back load. δCBF was significantly correlated with δCMRO₂ in controls, but not in SCD subjects. As N-back loads increased, the differences between SCD and control subjects in δCBF and δCMRO₂ tended to enlarge. In the parietal lobe, no significant between-group difference was observed. Our findings suggested that impaired vascular and metabolic responses to functional tasks occurred in the frontal lobe of SCD, which contributed to unusual BOLD hyperactivation and was modulated by cognitive processing loads.     

Effect of an impermeant arginine-modifying reagent on the responses of rabbit platelets to agonists

The importance of surface arginyl residues in platelet aggregation was investigated by studying the effects of an impermeant arginine-modifying reagent, p-sulfonylphenylglyoxal (PSPG), on platelet responses to various agonists. Pretreatment of resuspended rabbit platelets with 2-15 mM PSPG resulted in complete inhibition of aggregation responses to ADP and 5-HT, and a concentration-dependent inhibition of the preceding shape change. Aggregation responses to thrombin also were inhibited in a concentration-dependent manner. The protective effects of antagonists of these three agonists (beta, gamma-methylene ATP for ADP, hirudin for thrombin and phentolamine for 5-HT) during pretreatment of platelets with PSPG indicated that intact arginine residues form part of the receptor sites for ADP and for thrombin. Arginine residues are not part of the 5-HT receptor site itself, but seem to be important for the maintenance of the functional integrity of this site.     

A systematic review of cerebral hemodynamic responses to neural activation following stroke

The aim of this study was to systematically review CBF studies, assess their methodological quality, and identify trends in the association between task-related brain activation patterns and CBF changes in ischemic stroke (IS) patients. We searched the MEDLINE, EMBASE, CINAHL, and Web of Sciences databases for studies of functional recovery with quantification of CBF responses to brain activation paradigms after IS. Titles, abstracts and full text of articles were scrutinised according to pre-defined selection criteria. Two independent reviewers (AS, VH) undertook the methodological quality screening and data extraction of the included studies. Sixteen of the 1,521 identified studies were relevant. Studies showed weaknesses in key methodological criteria (e.g. population size, discussion of limitations), and only seven studies compared responses with a control population. Overall, there was no agreement between CBF responses in either the affected or unaffected hemisphere and prediction of post-IS recovery. Some studies have shown a higher CBF increase in the unaffected hemisphere when the affected hemisphere was stimulated compared to the healthy control responses. However, CBF responses in the affected hemisphere were inconsistent. Many post-IS CBF studies are of poor methodological quality, and do not demonstrate a consistent response post-IS or a relationship with recovery. Further longitudinal studies assessing the natural history of CBF responses to brain paradigms following IS should be undertaken to determine prognostic significance, and to inform future therapeutic strategies.     

Effect of kynurenine 3-hydroxylase inhibition on the dyskinetic and antiparkinsonian responses to levodopa in Parkinsonian monkeys.

Homeostatic interactions between dopamine and glutamate are central to the normal physiology of the basal ganglia. This relationship is altered in Parkinsonism and in levodopa-induced dyskinesias (LID), resulting in an upregulation of corticostriatal glutamatergic function. Kynurenic acid (KYNA), a tryptophan metabolite with antagonist activity at ionotropic glutamate receptors and the capability to inhibit glutamate release presynaptically, might therefore be of therapeutic value in LID. To evaluate this hypothesis, we used a pharmacological tool, the kynurenine 3-hydroxylase inhibitor Ro 61-8048, which raises KYNA levels acutely. Ro 61-8048 was tested in MPTP cynomolgus monkeys with a stable parkinsonian syndrome and reproducible dyskinesias after each dose of levodopa. Serum and CSF concentrations of KYNA and its precursor kynurenine increased dose-dependently after Ro 61-8048 administration, alone or in combination with levodopa. Coadministration of Ro 61-8048 with levodopa produced a moderate but significant reduction in the severity of dyskinesias while maintaining the motor benefit. These results suggest that elevation of KYNA levels through inhibition of kynurenine 3-hydroxylase constitutes a promising novel approach for managing LID in Parkinson's disease.     

EEG and ERP responses to naloxone and ethanol in monkeys

1. EEG and auditory event related potentials (ERPs) were recorded in monkeys following administration of water, naloxone (1, 10 mg/kg), or ethanol (0.75, 1.5 g/kg) plus naloxone (1 mg/kg). 2. Significant increases in EEG slow waves in the 2-8 Hz frequencies were seen following the 10 mg dose of naloxone. No significant EEG effects were observed at the 1 mg dose. 3. Naloxone was found to decrease the amplitude of the N1 component at the low doses and increase the N1 amplitude at the higher doses, whereas both doses reduced the latency of the P2 and P3 components of monkey auditory ERPs. 4. Low doses of ethanol (0.75 g/kg) and Naloxone (1 mg/kg) were found to produce a decrease in amplitude of the P3 response when compared to administration of naloxone alone. Whereas higher ethanol doses reversed some of the actions of naloxone on the latency of the P2 and P3 component of the ERP. 5. These studies suggest that opioid systems may participate in some aspects of attention or stimulus evaluation in the squirrel monkey.     

牛磺酸治疗高同型半胱氨酸脑梗死患者动脉粥样硬化的临床观察

Objective To investigate the therapeutic effect of taurine on atherosclerosis in patients with hyperhomocysteinemia (Hhcy)-induced cerebral infarction (CI). Methods Forty patients with CI induced by Hhcy were randomizod into two equal groups to receive taurine injections or folacin plus vitamin B12 treatment for 6 months. Color Doppler ultrasound was performed to examine the intima-media thickness (IMT) and the plaques in the carotid artery before and after the treatment. Blood samples were obtained from the patients to determine the changes in plasma homocysteic acid (Hcy) level using high-pressure liquid chromatography. Results Both taurine injections and folacin plus vitamin BI2 treatment for 6 months resulted in a significant reduction in the IMT of the carotid artery (P<0.05), but taurine caused a significantly greater reduction (0.551 mm vs 0.372 mm, P<0.05). Taurine also showed a better effect than folacin plus vitamin B12 in decreasing the number of atherosclcrotic plaques (P<0.05). Taurine treatment significantly decreased the plasma Hcy level as compared with the level before treatment (19.316±2.240 μmol/L v, 29.832±7.750 μmol/L, P<0.05). Conclusions Taurine has better therapeutic effect than folacin plus vitamine B12 oil atherosclerosis and helps control plasma Hcy level in patients with Hhcy-induced CI.     

牛磺酸治疗高同型半胱氨酸脑梗死患者动脉粥样硬化的临床观察

目的 探讨牛磺酸对高同型半胱氨酸脑梗死患者动脉粥样硬化的治疗作用. 方法选择自2006年9月至2006年12月哈尔滨医科大学附属第一医院神经内科住院的40例高同型半胱氨酸脑梗死患者,按随机数字表法分为牛磺酸治疗组和叶酸、维生素治疗组,相应的药物治疗6个月.治疗前后分别检查颈动脉彩超,观察颈动脉内膜中层厚度(IMT)和斑块变化情况,采血分离血清,采用高压液相色谱分析仪及相应试剂盒测定血浆同型半胱氨酸水平. 结果经治疗6个月后,叶酸、维生素组颈动脉IMT平均厚度减小0.372 mm,牛磺酸治疗组减小0.551 mm,两组在治疗前后颈动脉IMT比较差异均有统计学意义(P<0.05),且牛磺酸治疗组对颈动脉IMT的控制要优于叶酸、维生素治疗组,差异有统计学意义(P<0.05).牛磺酸治疗组治疗前后血浆同型半胱氨酸水平[(29.832±7.750)μmol/Lvs(19.316±2.240)μmol/L]比较差异有统计学意义(P<0.05). 结论牛磺酸对高同型半胱氨酸脑梗死患者动脉粥样硬化的治疗有效且优于叶酸、维生素,并对血浆同型半胱氨酸水平有控制作用.     

Effect of diabetes mellitus on responses of the basilar artery in rats to products released by platelets.

BACKGROUND AND PURPOSE: Aggregation and adherence of platelets to vascular endothelium are increased during diabetes mellitus, and thus responses of cerebral arteries to products released by platelets may have important implications for the pathogenesis of stroke during diabetes. The goal of this study was to determine whether responses of the basilar artery to products released by platelets are altered during diabetes. METHODS: A craniotomy was performed over the ventral medulla to expose the basilar artery. Diameter of the basilar artery was measured using intravital microscopy in nondiabetic and diabetic (50-60 mg/kg i.p. streptozotocin) rats in response to adenosine 5'-diphosphate, serotonin, and the thromboxane analogue U-46619. RESULTS: Topical application of 10 and 100 microM adenosine 5'-diphosphate produced only minimal changes in diameter of the basilar artery that were similar in nondiabetic and diabetic rats (p greater than 0.05). At 0.01, 0.1, and 1.0 microM serotonin produced dose-related constriction of the basilar artery that was similar in nondiabetic and diabetic rats (p greater than 0.05). At 0.1 and 1.0 microM U-46619 also produced similar dose-related constriction of the basilar artery in nondiabetic and diabetic rats (p greater than 0.05). CONCLUSIONS: These findings suggest that responses of the basilar artery to products released by platelets are not altered by diabetes mellitus. Thus, it does not appear that alterations in reactivity of the basilar artery to products released by platelets contribute to the pathogenesis of stroke during diabetes.