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。     

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.     

Society stress and peptic ulcer perforation

To examine the relationship between society stress and peptic ulcer perforation, time-trend analysis was performed on the annual incidence of perforated peptic ulcer per 100 000 population in Hong Kong during the years 1962–85, when Hong Kong, as a developing city, went through significant socio-economic and political changes, and the trend was correlated with specially designed and validated society stress scores estimated annually during the same period. The society stress scores were derived independently by two expert panels blinded to the purpose of the study, one selecting and categorizing negative news events for Hong Kong during this period, and the other weighing the categories and scoring the impact of the news on Hong Kong. The incidence of perforation increased significantly during the years and manifested three distinct peaks, which coincided with the worst economic recession in Hong Kong, the influx of mainlander Chinese and Vietnamese boat people, and the Sino-British negotiation on the sovereignty of Hong Kong after 1997. Both linear and autoregression analysis, the latter taking into consideration point fluctuations in rates, showed that perforation rates correlated significantly with the society stress scores (r= 0.57, P < 0.002). The peak effects and the significant correlations indicate that an association exists between society stress and peptic ulcer perforation, and suggest that chronic society stress plays an important role in the aetiology of this condition, although the relatively low r value also suggests the presence of other aetiological factors.     

Thrombospondin interaction with plasminogen. Evidence for binding to a specific region of the kringle structure of plasminogen

Platelet thrombospondin interacts with plasminogen in a specific and saturable manner. Thrombospondin was found to specifically bind to plasminogen and the nonenzyme chain of plasmin. Preincubation of 125I- labeled thrombospondin with 30 mmol/L lysine was without effect in the binding of thrombospondin to immobilized plasminogen; preincubation of 125I-labeled plasminogen with 30 mmol/L lysine, on the other hand, significantly reduced the binding of plasminogen to immobilized thrombospondin, suggesting that the interaction of thrombospondin with plasminogen is not the direct result of the lysine binding sites of plasminogen. Arginine and benzamidine, ligands known to specifically bind to the kringle 5 domain of plasminogen, blocked the binding of thrombospondin to plasminogen. Limited elastase proteolysis of plasminogen and plasmin resulted in the generation of two distinct thrombospondin binding domains, one of which was retained on lysine- agarose. The isolation and amino-terminal analysis of these domains following elastase proteolysis of plasminogen identified them, respectively, as a domain containing kringle structures 4 and 5 and plasmin and the other domain consisting of kringle 5-plasmin. A 16- residue synthetic peptide, which represents the amino acids linking kringle 4 to kringle 5 (residues 435-450 of native plasminogen), was without effect in either binding to thrombospondin or blocking the binding of thrombospondin to plasminogen. Plasminogen, therefore, possesses a single thrombospondin interactive site that is independent of, but influenced by, the lysine binding site containing kringle structures and most likely is located within the kringle 5 domain.     

Spectrin Nice (beta 220/216): a shortened beta-chain variant associated with an increase of the alpha I/74 fragment in a case of elliptocytosis

We describe a new spectrin variant with a truncated beta-chain. It was discovered in a 17-year-old white boy presenting with intermittent jaundice and spleen enlargement. He also displayed numerous smooth elliptocytes. On sodium dodecyl sulfate-polyacrylamide gel, the truncated beta-chain (beta'-chain) appeared as an additional band of approximately 216 kilodaltons, migrating between spectrin beta-chain and ankyrin. It represented 30% of total beta-chain. The beta'-chain reacted with an antispectrin beta-chain monoclonal antibody. It failed to become phosphorylated when ghosts were incubated in the presence of [gamma-32P] adenosine triphosphate. Whole spectrin tetramerization was defective since the amount of spectrin dimer was increased in spectrin crude extract and the association constant of the spectrin dimer self- association was decreased. Spectrin whole tetramer isolated from spectrin crude extracts contained small quantities of beta'-chain. Spectrin tryptic peptides showed an increase of the 74,000-dalton fragment at the expense of the 80,000-dalton fragment. So far, the latter abnormality has been used to characterize a number of cases of hereditary elliptocytosis or pyropoikilocytosis with no other apparent change. In the present case, we consider that the abnormality is a consequence of the beta-chain alteration. The parents seemed asymptomatic. As a result, we regard this new spectrin variant as deriving from a de novo mutation.     

Collection of peripheral blood hematopoietic progenitors (PBHP) from patients with severe aplastic anemia (SAA) after prolonged administration of granulocyte colony-stimulating factor

The aim of this study was to test whether prolonged administration of granulocyte colony-stimulating factor (G-CSF) would allow the collection by leukapheresis of PBHP in patients with SAA. For this purpose, nine SAA patients, 7 to 46 years old, six of whom were enrolled at diagnosis of their disease and three after previous immunosuppression had failed, were treated with antilymphocyte globulin (ALG) (day 1 to 5), cyclosporin A (5 mg/kg/d orally) (day 6 to 90) and G-CSF 5 micrograms/kg/d (day 6 to 90). A total of 40 leukaphereses were performed, (range 2 to 7 per patient), between days +10 and +168 from G- CSF treatment. White blood cell count at the time of harvest ranged from 1.2 to 18.1 x 10(9)/L. Results can be summarized as follows: the median number of cells collected per patient was 5.0 x 10(8)/kg (range 2.6 to 18.7), the median number of CD34+ cells was 1.8 x 10(6)/kg (range 0.27 to 3.8) and the median number of colony-forming units granulocyte-macrophage (CFU-GM) was 3.9 x 10(4)/kg (range 0 to 39). Twenty leukaphereses performed between days +33 and +77 of G-CSF treatment grew granulocyte macrophages and erythroid colonies in vitro. No colony growth was obtained from 20 leukaphereses performed before day +33 or after day +80. In six patients the total number of CFU-GM recovered were in the range described for autologous peripheral blood stem cell grafts. (2.6 to 39 x 10(4)/kg). In conclusion, this study suggests that circulating hematopoietic progenitors can be recovered after ALG priming and after at least 1 month of G-CSF treatment in a proportion of patients with SAA. Whether these cells will be suitable for autologous transplantation remains to be determined.