Factors Affecting the Risk of Blood Bank Specimen Hemolysis

OBJECTIVES: To evaluate simultaneously several possible risk factors for blood bank specimen hemolysis. METHODS: This was a prospective cohort study of emergency department and labor and delivery patients to estimate the effect of various factors on the risk of blood bank specimen hemolysis. Study variables included patient demographics, type and gauge of needle or catheter, anatomic location of venipuncture, and patient care area. Hemolysis was determined by blood bank laboratory technicians. Cox proportional hazards multivariate regression modeling was performed to estimate the adjusted relative risks for hemolysis. RESULTS: Of the 605 subjects with complete data, 194 (32.1%) subjects had blood specimens drawn directly with a steel needle, and 411 (69.1%) had specimens drawn through a Vialon (BD Medical Systems, Inc., Sandy, UT) intravenous (IV) angiocatheter. The overall risk of hemolysis for all was 7%, 10% for Vialon IV angiocatheters and 1.5% for steel needles. In the multivariate analysis, the factors most closely associated with hemolysis were the use of Vialon IV catheters and sampling from an anatomic site other than the antecubital area. CONCLUSIONS: Blood bank specimens drawn from Vialon IV catheters (particularly smaller gauge catheters) and from veins outside the antecubital area are at significantly increased risk to hemolyze.     

原代培养猪甲状腺细胞及甲状腺过氧化物酶活性与氟化钠的影响

目的:流行病学调查结果显示,地方性氟中毒与甲状腺肿的流行有很大的重叠性。探讨氟化钠对原代培养猪甲状腺细胞及甲状腺过氧化物酶活性的影响。方法:实验于2006-10/2007-05在辽宁医学院科学实验室中心完成。①实验方法:在猪死亡1h内取其甲状腺组织,去除甲状腺组织包膜及外层活性差的组织,选取中央活性高的部位,剪成1mm3组织块,用胰蛋白酶、胶原酶Ⅳ消化分离,得到含猪甲状腺细胞的消化液,沉淀悬于含体积分数为0.15的胎牛血清、1U/L牛促甲状腺素、80万U/L庆大霉素的F12培养基中,过滤,调整细胞浓度至5×105L-1,接种培养,每3d更换培养液。常规培养48h的猪甲状腺细胞接种于96孔培养板,按氟化钠终浓度不同分为0,40,80,160mg/L组。②实验评估:染毒48h后,采用噻唑蓝法测定细胞存活量,采用改良愈创木酚法测定甲状腺过氧化物酶活性。结果:①氟化钠对原代培养猪甲状腺细胞存活量的影响:与0mg/L氟化钠比较,40mg/L氟化钠染毒后猪甲状腺细胞的存活量基本相似;80,160mg/L氟化钠染毒后猪甲状腺细胞的存活量均明显下降(P<0.01)。②氟化钠对甲状腺过氧化物酶活性的影响:与0mg/L氟化钠比较,40,80,160mg/L氟化钠染毒后的甲状腺过氧化物酶活性均明显下降(P<0.01),呈剂量-效应关系。结论:氟化钠对原代培养的猪甲状腺细胞及甲状腺过氧化物酶活性均具有抑制作用。     

Cicletanine reverses vasoconstriction induced by the endogenous sodium pump ligand, marinobufagenin, via a protein kinase C dependent mechanism

RATIONALE: Cicletanine (CIC), an anti-hypertensive compound with direct vascular and natriuretic actions, is especially effective in salt-sensitive hypertension, in which dysregulation of the sodium pump plays an important pathogenic role, and digitalis-like cardiotonic steroids contribute to increased vascular tone. The purpose of the present study was to investigate whether, and by what mechanisms, cicletanine antagonizes the vasoconstrictor effects of cardiotonic steroids in isolated human arteries. METHODS: The effects of cicletanine on vascular tone were studied in isolated, endothelium-denuded rings of 2nd-3rd-order branches of human mesenteric arteries pre-contracted with bufodienolide marinobufagenin (MBG), an Na/K-ATPase inhibitor, or endothelin-1 (ET-1). Na/K-ATPase activity was measured in sarcolemmal membranes from the mesenteric artery. Activity of rat brain protein kinase C (PKC) was measured using the PepTag phosphorylation assay. RESULTS: MBG and ET-1 both induced sustained vasoconstriction in human mesenteric artery rings, and cicletanine relaxed rings pre-contracted with either MBG (EC50 = 11 +/- 2 micromol/l) or ET-1 (EC50 = 6.4 +/- 1.1 micromol/l). Although 8-Br-cGMP (100 micromol/l) caused complete vasorelaxation of arterial rings pre-contracted with ET-1, it did not affect the MBG-induced vasoconstriction. An activator of PKC, phorbol diacetate (PDA) (50 nmol/l), attenuated CIC-induced vasorelaxation of mesenteric artery rings pre-contracted with MBG (EC50 > 100 micromol/l), but not rings pre-contracted with ET-1 (EC50 = 6.5 +/- 1.2 micromol/l). In mesenteric artery sarcolemma, 100 nmol/l MBG inhibited the Na/K-ATPase by 68 +/- 5% and cicletanine (100 micromol/l) attenuated this Na/K-ATPase inhibition by 85 +/- 6%. In the PepTag PKC assay, cicletanine produced a concentration-dependent inhibition of rat brain PKC activity (IC50 45 +/- 11 micromol/l). In the presence of 50 nmol/l PDA, 100 micromol/l cicletanine did not antagonize the Na/K-ATPase inhibition by MBG, and did not inhibit the PKC from rat brain. CONCLUSIONS: Cicletanine antagonizes vasoconstriction induced by Na/K-ATPase inhibition via a PKC-dependent mechanism that does not involve inhibition of cyclic GMP phosphodiesterase (cGMP-PDE). This mechanism of action may be relevant to the greater potency of cicletanine in salt-sensitive hypertension in which plasma levels of endogenous digitalis-like cardiotonic steroids are elevated. Our findings also suggest that PKC is an important factor for cardiotonic steroid-Na/K-ATPase interactions on the vascular tone, and is therefore a potential target for therapeutic intervention in hypertension.     

Impact of Ganogerma applanatum extraction on haematological profiles of laboratory rats: a preliminary study in Nigeria

ObjectiveExtracts of Ganoderma species have been widely used as herbal medicines in the treatment of several infections. This study was carried out to ascertain the haematological properties of aqueous Ganoderma applanatum (G. applanatum).MethodsSixty albino rats grouped into six equal groups (10 each) of A to F consisting of tests and controls. Laboratory albino rats in groups A, B and C were infected with Trypanosoma brucei brucei (T. brucei brucei) while groups A and B (test) were treated with aqueous G. applanatum extract; other groups served as control. Microscopy and haematological profiles from the albino rats were monitored on daily basis for blood parasites, packed cell volume (PCV), haemoglobin concentration (HC), total red blood cell count (RBC), mean cell haemoglobin (MCH), mean cell volume (MCV), mean cell haemoglobin concentration (MCHC), and total white blood cell count (WBC).ResultsAlbino rats in groups A, B and C infected with T. brucei brucei and treated with various concentrations of aqueous G. applanatum showed a progressive reduction in PCV, HC, RBC, MCH and MCHC compared to the controls (P<0.05). All the infected rats died by day 14 of the experiment from parasitaemia.ConclusionsG. applanatum lacks ability to boost haematological profiles of anaemic laboratory rats and also of no use in the treatment of African trypanosomiasis. Higher doses of the fungal extract may be required to test on laboratory rats with less lethal biological stimulants of anaemia before proving or otherwise its true haematological properties.     

The Tie receptor tyrosine kinase is expressed by human hematopoietic progenitor cells and by a subset of megakaryocytic cells

Growth factor receptors in human hematopoietic progenitor cells have become the focus of intense interest, because they may provide tools for the monitoring, enrichment, and expansion of stem cells. We have shown earlier that the Tie receptor tyrosine kinase is expressed in erythroid and megakaryoblastic human leukemia cell lines, in the blood islands of the yolk sac, and in endothelial cells starting from day 8.0 of mouse development. Here, the expression of Tie was studied in human hematopoietic cells of various sources. Peripheral blood mononuclear cells were Tie-. However, a large fraction of CD34+ cells from umbilical cord blood (UCB) and bone marrow (BM) expressed tie protein and mRNA. On average, 64% of the fluorescence-activated cell sorting- gated UCB CD34+ cells including CD38- cells and a fraction of cells expressing low levels of c-Kit were Tie+. Also, 30% to 60% of BM CD34+ cells were Tie+, including most of the BM CD34+CD38-, CD34+Thy-1+, and CD34+HLA-DR- cells. Under culture conditions allowing myeloid, erythroid, and/or megakaryocytic differentiation, purified UCB CD34+ cells lost Tie mRNA and protein expression concomitantly with that of CD34; however, a significant fraction of cells expressed Tie during megakaryocytic differentiation. These data suggest that, in humans, the Tie receptor and presumably its ligand may function at an early stage of hematopoietic cell differentiation.