Effect of spark plasma sintering on the microstructure and in vitro behavior of plasma sprayed HA coatings

The crystalline phases and degree of crystallinity in plasma sprayed calcium phosphate coatings on Ti substrates are crucial factors that influence the biological interactions of the materials in vivo. In this study, plasma sprayed hydroxyapatite (HA) coatings underwent post-spray treatment by the spark plasma sintering (SPS) technique at 500 degrees C, 600 degrees C, and 700 degrees C for duration of 5 and 30 min. The activity of the HA coatings before and after SPS are evaluated in vitro in a simulated body fluid. The surface microstructure, crystallinity, and phase composition of each coating is characterized by scanning electron microscopy and X-ray diffractometry before, and after in vitro incubation. Results show that the plasma sprayed coatings treated for 5 min in SPS demonstrated increased proportion of beta-TCP phase with a preferred-orientation in the (214) plane, and the content of beta-TCP phase corresponded to SPS temperature, up to 700 degrees C. SPS treatment at 700 degrees C for 30 min enhanced the HA content in the plasma spray coating as well. The HA coatings treated in SPS for 5 min revealed rapid surface morphological changes during in vitro incubation (up to 12 days), indicating that the surface activity is enhanced by the SPS treatment. The thickest apatite layer was found in the coating treated by SPS at 700 degrees C for 5 min.     

Anti-myeloperoxidase IgG subclass distribution and avidity in sera from patients with propylthiouracil-induced antineutrophil cytoplasmic antibodies associated vasculitis

OBJECTIVE: Propylthiouracil (PTU) could induce MPO-ANCA-positive vasculitis. The aim of this study was to compare the IgG subclass distribution and avidity of MPO-ANCA in sera from patients with primary ANCA-associated vasculitis (AASV) and PTU-induced vasculitis. METHODS: Nineteen patients with primary AASV with MPO-ANCA and thirteen patients with PTU-induced vasculitis were enrolled in the current study. Sera in both active phase and remission were collected. Anti-MPO IgG subclasses were detected by antigen specific ELISAs using specific monoclonal antibodies as second antibodies, and MPO-ANCA avidity was assessed by antigen-inhibition ELISAs. RESULTS: In primary AASV, all four anti-MPO IgG subclasses could be detected in active phase with IgG1 (100%), IgG2 (73.7%), IgG3 (63.2%) and IgG4 (94.7%), and in remission, IgG1 and IgG4 subclasses in most patients remained positive. However, in PTU-induced vasculitis, anti-MPO IgG3 subclass could not be detected, the anti-MPO IgG subclasses in active phase were IgG1 (100%), IgG2 (61.5%) and IgG4 (46.2%). Furthermore, five out of the six patients (88.8%) with PTU-induced vasculitis with positive IgG4 subclass in active phase turned to negative in remission, however, only eight out of the fourteen patients (57.1%) with primary AASV turned to negative. The median avidity constant of MPO-ANCA was 56 (8.96 to >140) x 10(7) mol/l for patients with primary AASV and 0.7 (<0.28 to >140) x 10(7) mol/l for patients with PTU-induced vasculitis respectively. Furthermore, the relative levels of MPO-ANCA avidity were associated with elevation of ESR in primary AASV and were associated with BVAS scores in patients with PTU-induced vasculitis, respectively. CONCLUSION: MPO-ANCA IgG subclass distribution and avidity were different between patients with primary AASV and PTU-induced vasculitis. It was suggested that the mechanism of ANCA production in PTU-induced vasculitis was different from that in primary AASV, and the avidity of MPO-ANCA might be associated with disease activity.     

狗股动脉弹性纤维的扫描电镜观察

用甲酸消化法制取正常股动脉弹性纤维标本，冷冻干燥后进行扫描电镜观察。见到内弹性膜上有许多散分布的窗孔，中膜的弹性经组织呈复杂的网状，外膜的弹性组织以粗大的纵向分层排列的弹性纤维为主。     

单克隆抗体间接荧光法分型检测单纯疱疹病毒的实验研究

本文选择３株抗单纯疱疹病毒型共同性和型特异性单克隆抗体，建立了分型检测单纯疱疹病毒的单克隆抗体间接荧光法（ＭｃＡｂ－１ＦＡ）．特异性试验和重复性试验证实，ＭｃＡｂ－ＩＦＡ特异性强、重复性好．用此法检测了不同部位来源的５１份临床分离株，分型检测结果与ＥＬＩＳＡ法检测结果一致．提示ＭｃＡｂ－ＩＦＡ有可能成为实验室分型检测单纯疱疹病毒可靠的方法．     

Status of hepatitis B virus DNA in hepatocellular carcinoma: a study based on paired tumor and nontumor liver tissues

To investigate the hepatitis B virus (HBV) DNA status in the liver when hepatocellular carcinoma (HCC) has developed, 35 paired nontumorous and tumorous liver tissues from 27 hepatitis B surface antigen (HBsAg)-seropositive and 8 HBsAg-negative patients with HCC were studied by Southern blot analysis. The hybridization patterns of HBV DNA were different in the nontumor and tumor parts in 26 (96.3%) of the 27 HBsAg-positive patients. In the nontumor parts, integration of HBV DNA into the host genome was significantly less when compared to the tumor parts (15/27 vs. 25/27, P less than 0.05), whereas free replicative viral forms were significantly more frequent (17/27 vs. 7/27). The integrated HBV DNA in the nontumor parts showed discrete band patterns in the majority of cases (13/15). Hepatitis B e antigen (HBeAg) was significantly associated with the expression of free replicative forms of HBV DNA in the tumor tissues. An integrated HBV DNA sequence was detected in the tumor part of one HBsAg-negative patient, but not in her nontumor counterpart. Our observation that discrete integrated HBV DNAs are present in the nontumor part, representing subclinical clonal expansion that precedes the development of HCC, suggests the risk of future new tumor growth from these cell clones.     

Role of proliferation and differentiation of hemopoietic precursors in regeneration of hemopoiesis in cytostatic myelodepressions

Quantitative and qualitative composition of hemopoietic tissue and the intensity of proliferation and differentiation of committed hemopoietic precursors are studied in mice treated with adriamycin, cyclophosphane, or 5-fluorouracil. It is shown that intense maturation of colony-forming units results in rapid regeneration of hemopoiesis even under conditions of reduced proliferation of these cells, whereas inhibition of their differentiation suppresses restoration of bone marrow cellularity despite intense proliferation of hemopoietic precursors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 12, pp. 616–620, December, 1997     

Participation of hematopoietic stem cells in formation of the immune response

The effect of different doses of sheep's red blood cells (SRBC) on endogenous colony formation and immunogenesis was studied in CBA and C57BL mice. The absolute and relative numbers of antibody-forming cells (AFC) was shown to increase with an increase in the dose of SRBC from 2×10⁷ to 2×10⁸, and to decrease with a dose of 2×10⁹ in mice of both lines. With an increase in the dose of antigen, the number of endogenous splenic colonies (ESC) of hematopoietic cells also increased. Interlinear differences in the number of ESC persisted. It is suggested that the mechanism of stimulation of the hematopoietic series is based on a unique type of blockade of the reticuloendothelial system by foreign red blood cells, leading to increased proliferative activity of the stem cells.Laboratory of Regulation of Immunopoiesis, Institute of Clinical and Experimental Medicien, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4, pp. 330–332, April, 1979.