高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数

本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4～5.6%,血浓69.6～1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。     

Uptake and intracellular distribution of idarubicin in secondary cultures of normal and neoplastic urothelium

This study analyzes the uptake and endocellular distribution of idarubicin (IDA) in normal and neoplastic urothelial secondary cultures in relation to the changes in concentration and time of exposure. The urothelial lines were isolated by Freshney's method from biopsy fragments taken from five patients with superficial bladder cancer. Pharmacological experiments were carried out on subcultures previously immunophenotypically characterized and did not exceed ten passages. The uptake and endocellular distribution of IDA was analyzed by densitometric image analysis on cells treated for 10, 20, 30 and 60 min and 2 h with scalar dosages from 10 ng/ml to 2430 ng/ml. Microscopic observations and densitometric analyzes revealed that in the cells treated with IDA, fluorescence was higher in the cytoplasm compared to the nucleus and increased with the change in dosage. Moreover, densitometric data showed that IDA uptake in the first 20 min was higher in the neoplastic cells, but after that period its behavior became heterogeneous at 30 and 60 min, while at 2 h there was an inversion of the trend. These results suggest that the in vitro cytotoxicity should be evaluated in order to verify whether the elevated uptake of IDA in the first 20 min of treatment is really correlated to a more elevated toxicity in the neoplastic cells with respect to the normal cells. This is presently under investigation.     

Angiogenic response induced by acellular aortic matrix in vivo

In this study, we investigated the angiogenic response induced by acellular aortic matrices implanted in vivo onto the chick embryo chorioallantoic membrane (CAM), a useful model for such investigation. Results showed that acellular matrices were able to induce a strong angiogenic response comparable to that of fibroblast growth factor 2 (FGF-2), a well-known angiogenic cytokine. The angiogenic response was further increased when exogenous FGF-2 or transforming growth factor beta 1 (TGF-beta1) were added to the matrices and inhibited by the addition of an anti-FGF-2 or anti-TGF-beta1 antibodies. The response may be considered dependent on a direct angiogenic effect exerted by the matrices and in part also by the presence of FGF-2 and TGF-beta1 in the acellular matrices.     

Novel osteoblast-adhesive peptides for dental/orthopedic biomaterials

Next generation dental/orthopedic biomaterials must be designed to enhance and support osteoblast adhesion. The osteoblasts use different ways to adhere, that is, integrin- and proteoglycan-mediated mechanisms. The present study reports on the synthesis and osteoblast-adhesive properties of peptides carrying RGD motifs and of sequences mapped on human vitronectin. Our data suggest that osteoblast adhesion on polystyrene plates modified with a linear peptide, in which the GRGDSP sequence is repeated four times, was significantly higher when compared to the adhesion obtained using branched peptides, interestingly containing the same motif. Osteoblast adhesion assays on acellular bone matrix using this active peptide gave very promising results. We also demonstrated that a novel peptide, carrying the X-B-B-B-X-B-B-X motif (where B is a basic amino acid and X is a nonbasic residue), promotes proteoglycan-mediated osteoblast adhesion more efficiently with respect to the KRSR sequence that was recently proposed as heparan-sulfate binding peptide.     

The UTX gene escapes X inactivation in mice and humans

We recently have identified a ubiquitously transcribed mouse Y chromosome gene, Uty , which encodes a tetratricopeptide repeat (TPR) protein. A peptide derived from the UTY protein confers H-Y antigenicity on male cells. Here we report the characterization of a widely transcribed X-linked homologue of Uty , called Utx , which maps to the proximal region of the mouse X chromosome and which detects a human X-linked homologue at Xp11.2. Given that Uty is ubiquitously transcribed, we assayed for Utx expression from the inactive X chromosome (Xi) in mice and found that Utx escapes X chromosome inactivation. Only Smcx and the pseudoautosomal Sts gene on the mouse X chromosome have been reported previously to escape inactivation. The human UTX gene was also found to be expressed from Xi. We discuss the significance of these data for our understanding of dosage compensation of X-Y homologous genes in humans and mice.      

L1 knockout mice show dilated ventricles, vermis hypoplasia and impaired exploration patterns

L1 is a neural cell adhesion molecule mainly involved in axon guidance and neuronal migration during brain development. Mutations in the human L1 gene give rise to a complex clinical picture, with mental retardation, neurologic abnormalities and a variable degree of hydrocephalus. Recently, a transgenic mouse model with a targeted null mutation in the L1 gene was generated. These knockout (KO) mice show hypoplasia of the corticospinal tract. Here we have performed further studies of these KO mice including magnetic resonance imaging of the brain, neuropathological analysis and behavioral testing. The ventricular system was shown to be abnormal with dilatation of the lateral ventricles and the 4th ventricle, and an altered shape of the Sylvius aqueduct. Additionally, the cerebellar vermis of the KO mice is hypoplastic. Their exploratory behavior is characterized by stereotype peripheral circling reminiscent of that of rodents with induced cerebellar lesions.