介入治疗激素性股骨头坏死的实验研究

目的：探讨介入治疗激素性股骨头坏死的作用机制。方法：将24只兔子随机分为对照组、模型组、介入组。于介入前后行血管造影检查，并于治疗后8周，分别进行血液流变学、血脂及病理学观察。结果：介入组血管中断现象改善，终末小血管数目增我。全血粘度、血浆粘度，红细胞聚集指数、总胆固醇、甘油三脂，股骨头空骨陷窝率均明显低于模型组（P＜0．05），软骨下区血管数目增多（P＜0．01）。结论：介入、静脉注射治疗股骨头坏死，可以降低血脂，改善血液循环，通过改善股骨头血供，降低骨内压，促进坏死骨修复和新骨再生。     

Two new triterpene esters from the twigs of Brachylaena ramiflora from the Madagascar rainforest

Bioassay-guided fractionation of a CH(2)Cl(2)/MeOH extract of the small twigs of Brachylaena ramiflora var. ramiflora resulted in the isolation of the two new triterpene esters 1 and 2 and five known triterpenoids, alpha-amyrin palmitate (3), beta-amyrin palmitate (4), beta-amyrin acetate (5), lupeyl acetate (6), and lupeol (7). The structures of the two new compounds were established as kairatenyl palmitate (1) and hopenyl palmitate (2) on the basis of 1D and 2D NMR spectroscopic data interpretation and chemical conversions. All the isolated compounds showed weak cytotoxicity against the A2780 human ovarian cancer cell line.     

SAR, pharmacokinetics, safety, and efficacy of glucokinase activating 2-(4-sulfonylphenyl)-N-thiazol-2-ylacetamides: discovery of PSN-GK1

Allosteric activators of the glucose-sensing enzyme glucokinase (GK) are currently attracting much interest as potential antidiabetic therapies because they can achieve powerful blood glucose lowering through actions in multiple organs. Here, the optimization of a weakly active high-throughput screening hit to (2 R)-2-(4-cyclopropanesulfonylphenyl)- N-(5-fluorothiazol-2-yl)-3-(tetrahydropyran-4-yl)propionamide (PSN-GK1), a potent GK activator with an improved pharmacokinetic and safety profile, is described. Following oral administration, this compound elicited robust glucose lowering in rats.     

Cytotoxic clerodane diterpenoids and their hydrolysis products from Casearia nigrescens from the rainforest of Madagascar

Bioassay-guided fractionation of the cytotoxic leaf and flower extract of Casearia nigrescens led to the isolation of four new clerodane diterpenoids, designated caseanigrescens A-D (1-4). These compounds were subject to hydrolysis to dialdehydes when stored in CDCl3. The structures of compounds 1-4 were determined using 1D and 2D NMR spectroscopy. All four compounds showed moderate cytotoxicity to the A2780 human ovarian cancer cell line, with an IC50 range of 0.83-1.4 microM.     

Antiproliferative xanthones of Terminalia calcicola from the Madagascar rain forest

A bioassay-guided fractionation of the EtOH extract of the Madagascan plant Terminalia calcicola led to the isolation of two new cytotoxic xanthones, termicalcicolanone A (1) and termicalcicolanone B (2). The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopic data. Both compounds showed modest antiproliferative activity toward the A2780 human ovarian cancer cell line.     

Comparison of the mutagenic potency of 1,3-butadiene at the hprt locus of T-lymphocytes following inhalation exposure of female B6C3F1 mice and F344 rats

1,3-Butadiene (BD) is an indirect alkylating agent that has greater cancer potency in the mouse than in the rat. The purpose of the present study was to compare the mutagenic potency of BD at the hprt locus of T- lymphocytes of exposed mice and rats and to determine whether mutations induced in this marker gene can be used as a quantitative indicator for species differences in susceptibility to cancer. To this end, experiments were conducted to define the effects of exposure duration and the time elapsed after exposures on the frequency of hprt mutations (Mf) in T-cells from female B6C3F1 mice and F344 rats of similar age (4- 5 weeks) when exposed to BD by inhalation. The accumulation of hprt mutations in T-cells from thymus was assessed in animals necropsied 2 weeks after exposure to 0 or 1250 ppm BD for 1 or 2 weeks, while the time course for the appearance of hprt mutant T-cells (i.e., the phenotypic expression and cell migration) in thymus and spleen was evaluated in animals necropsied at weekly/biweekly intervals up to 10 weeks after exposure for 2 weeks. At necropsy, T-cells were isolated from thymus and spleen and cultured in the presence of IL-2, concanavalin A, and 6-thioguanine (Walker and Skopek, Mutat. Res., 288, 151-162, 1993). BD exposures of 1 and 2 weeks led to mutagenic effects in mouse thymus, with the average Mfs being 3- and 5-fold greater than background values, respectively. In rat thymus, there was only a 1.7- fold increase in Mfs after 2 weeks of BD exposure. In the mutant expression experiment, hprt Mfs in thymus and spleen of both species increased for several weeks post-exposure and then declined. Hprt Mfs in thymus reached maximum levels at 2 weeks post-exposure in mice (Mfs = 11.3 +/- 2.4 x 10(-6)) and at 3 weeks post-exposure in rats (4.9 +/- 1.2 x 10(-6)), while hprt Mfs in spleen reached peak levels at 5 weeks post-exposure in mice (19.7 +/- 1.9 x 10(-6)) and 4 weeks post-exposure in rats (10.1 +/- 1.8 x 10(-6)). Background Mfs for mouse and rat thymus and spleen ranged from 1.6 +/- 0.3 x 10(-6) to 3.0 +/- 1.1 x 10(- 6). Statistical analyses of the hprt Mf data for spleen demonstrated that, under these exposure conditions, the mutagenic potency of BD (represented by the difference in the areas under the phenotypic expression curves of treated versus control animals) was 5-fold greater in mice than in rats. The magnitude of the species differences in mutagenic potency, observed after 2 weeks of BD exposure, resembles the species differences in metabolism more closely than the species differences in cancer potency.      

Murine yolk sac endoderm- and mesoderm-derived cell lines support in vitro growth and differentiation of hematopoietic cells

The mechanisms involved in the induction of yolk sac mesoderm into blood islands and the role of visceral endoderm and mesoderm cells in regulating the restricted differentiation and proliferation of hematopoietic cells in the yolk sac remain largely unexplored. To better define the role of murine yolk sac microenvironment cells in supporting hematopoiesis, we established cell lines from day-9.5 gestation murine yolk sac visceral endoderm and mesoderm layers using a recombinant retrovirus vector containing Simian virus 40 large T- antigen cDNA. Obtained immortalized cell lines expressed morphologic and biosynthetic features characteristic of endoderm and mesoderm cells from freshly isolated yolk sacs. Similar to the differentiation of blood island hematopoietic cells in situ, differentiation of hematopoietic progenitor cells in vitro into neutrophils was restricted and macrophage production increased when bone marrow (BM) progenitor cells were cultured in direct contact with immortalized yolk sac cell lines as compared with culture on adult BM stromal cell lines. Yolk sac- derived cell lines also significantly stimulated the proliferation of hematopoietic progenitor cells compared with the adult BM stromal cell lines. Thus, yolk sac endoderm- and mesoderm-derived cells, expressing many features of normal yolk sac cells, alter the growth and differentiation of hematopoietic progenitor cells. These cells will prove useful in examining the cellular interactions between yolk sac endoderm and mesoderm involved in early hematopoietic stem cell proliferation and differentiation.     

DNA Index in childhood acute lymphoblastic leukaemia: a karyotypic method to validate the flow cytometric measurement

The DNA index (DI) is a prognostic factor in childhood acute lymphoblastic leukemia (ALL). The accuracy of DI measurement is important for treatment stratification: hyperdiploidy with DI ≥ 1.16 is predictive of favorable prognosis whereas hypodiploidy is associated with poor prognosis. The aim of this study was to validate the accuracy of the DI measured by flow cytometry (FCM) by comparison with the karyotype. From samples of 112 childhood ALL, we created a formula to calculate a theoretical DNA index (tDI) based on the blast cell karyotype, taking into account the additional or missing chromosome material of the major clone. FCM DI correlated with tDI calculated from karyotype (R = 0.987) and with modal chromosome number (DI = 0.0202 × Modal NB + 0.0675 and R = 0.984). In three cases a hypodiploid blast cell population was detected by FCM, while only the duplicated clone was identified by the karyotype. The strong correlation between tDI and DI validates the accuracy of FCM quantification, which is technically fast on fresh or frozen samples. If the karyotype is essential to analyze chromosomal abnormalities, FCM provides complementary information in aneuploid ALLs, either by confirming the cytogenetic data or by detecting additional clones not identified when only using cytogenetic data.     

Homozygous alpha6 integrin mutation in junctional epidermolysis bullosa with congenital duodenal atresia

Junctional epidermolysis bullosa with congenital pyloric or duodenal atresia is a distinct variant within this group of autosomal recessive blistering skin diseases. In this study we demonstrate, for the first time, a homozygous mutation in the alpha6 integrin gene (ITGA6) in a family with three affected individuals. For this purpose, we first determined the genomic organization of ITGA6, and placed the gene on chromosome 2q by high resolution radiation hybrid mapping. Heteroduplex analysis of PCR products containing the individual exons of ITGA6, followed by direct nucleotide sequencing, revealed that the proband was homozygous for a G-to-T transversion in the +1 position of intron 12. This mutation, 1856+1G-->T, affects an invariant base of the 5' donor splice site predicting aberrant splicing involving exon 12. The mutation was verified in the proband's DNA by restriction enzyme digestion which also confirmed that the parents were heterozygous carriers of this mutation. Altered expression of alpha6 integrin, which forms a heterodimer with the beta4 subunit at the dermal-epidermal junction, would explain fragility and blistering as a result of minor trauma to the skin.