Cholesteryl-grafted functional amphiphilic poly(N-isopropylacrylamide-co-N-hydroxylmethylacrylamide): synthesis, temperature-sensitivity, self-assembly and encapsulation of a hydrophobic agent

A thermally responsive amphiphilic grafted copolymer comprised of hydroxyl-containing random poly(N-isopropylacrylamide-co-N-hydroxylmethylacrylamide) as the hydrophilic chain and cholesteryl groups as hydrophobic side arms was developed for the controlled release of hydrophobic drugs. The polymer was temperature-sensitive with a lower critical solution temperature of 40.5 degrees C and a critical micelle concentration of 4 mg/l. Dynamic light-scattering studies showed that the amphiphilic polymer self-assembled into micelles in aqueous media with their mean sizes in the range of 25-34 nm. Transmission electron microscope studies showed that the nanoparticles prepared from the micelle solutions exhibited multiple morphologies including unusual cubic and cuboids-like shapes, and normal spherical shapes, which could be controlled by the formation conditions. Wide-angle X-ray scattering studies showed that these nanoparticles were amorphous in nature but a small crystalline phase existed and the crystallinity of particles increased with the decrease of initial formation concentration. Pyrene was employed as a model hydrophobic agent to examine the encapsulation ability of the polymer with respect to hydrophobic agents in aqueous media. The loading level of the polymer with respect to pyrene was 4.4 mg/g, indicating that the thermally responsive amphiphilic polymer would be able to be used for the encapsulation of hydrophobic drugs.     

Optimization of combined electron and photon beams for breast cancer

Recently, intensity-modulated radiation therapy and modulated electron radiotherapy have gathered a growing interest for the treatment of breast and head and neck tumours. In this work, we carried out a study to combine electron and photon beams to achieve differential dose distributions for multiple target volumes simultaneously. A Monte Carlo based treatment planning system was investigated, which consists of a set of software tools to perform accurate dose calculation, treatment optimization, leaf sequencing and plan analysis. We compared breast treatment plans generated using this home-grown optimization and dose calculation software for different treatment techniques. Five different planning techniques have been developed for this study based on a standard photon beam whole breast treatment and an electron beam tumour bed cone down. Technique 1 includes two 6 MV tangential wedged photon beams followed by an anterior boost electron field. Technique 2 includes two 6 MV tangential intensity-modulated photon beams and the same boost electron field. Technique 3 optimizes two intensity-modulated photon beams based on a boost electron field. Technique 4 optimizes two intensity-modulated photon beams and the weight of the boost electron field. Technique 5 combines two intensity-modulated photon beams with an intensity-modulated electron field. Our results show that technique 2 can reduce hot spots both in the breast and the tumour bed compared to technique 1 (dose inhomogeneity is reduced from 34% to 28% for the target). Techniques 3, 4 and 5 can deliver a more homogeneous dose distribution to the target (with dose inhomogeneities for the target of 22%, 20% and 9%, respectively). In many cases techniques 3, 4 and 5 can reduce the dose to the lung and heart. It is concluded that combined photon and electron beam therapy may be advantageous for treating breast cancer compared to conventional treatment techniques using tangential wedged photon beams followed by a boost electron field.     

2,8-Dihydroxyadenine urolithiasis in a patient with considerable residual adenine phosphoribosyltransferase activity in cell extracts but with mutations in both copies of APRT

We have examined the mutational basis of adenine phosphoribosyltransferase (APRT, EC 2.4.2.7) deficiency (MIM 102600) in a patient of Polish origin who has been passing 2,8-dihydroxyadenine (DHA) stones since birth, but has considerable residual enzyme activity in lymphocyte extracts. The five exons and flanking regions of APRT were amplified by PCR and then sequenced. A single T insertion was identified at the intron 4 splice donor site (TGgtaa to TGgttaa:IVS4+2insT) in one allele from the proband, his mother, and brother. A G-to-T transversion in exon 5 (GTC-to-TTC:c.448G>T, V150F) was identified in the other allele, and this mutation was also present in one allele from the father and the paternal grandmother. Tru91 and AvaII digestions of PCR products spanning exons 4 and 5, respectively, confirmed the mutations. The mother was heterozygous for an intragenic TaqI site, but all other family members were homozygous for the presence of this site. IVS4+2insT, located on the allele containing the TaqI site, has been identified previously in several families from Europe, suggesting a founder effect, but the substitution in exon 5 is a novel mutation. IVS4+2insT is known to result in complete loss of enzyme activity, and our results suggest that V150F produces an enzyme that is nonfunctional in vivo but has considerable residual activity in vitro.     

Urea permeation and hydrolysis through hollow fiber dialyzer immobilized with urease

The surface of commercial polyacrylonitrile hollow fibers was hydrolyzed and covalently bonded with urease by using glutaraldehyde. Mini-modules assembled with these modified hollow fibers were then used to study the effect of concentration of glutaraldehyde, pH, and temperature on the catalysis of urea. The immobilized amount increased with the concentration of glutaraldehyde. However, urease immobilized with 5% glutaraldehyde had higher activity (0.38 micromol/min/mg-urease) than with other concentrations. The activity of the immobilized urease remained at above 0.32 micromol/min/mg-urease over wider applicable ranges of temperature (4-70 degreesC) and pH (5-8) compared to free urease. For comparison, the activity of immobilized urease was 0.35 micromol/min/mg-urease, while that for non-immobilized urease was 0.33 micromol/min/mg-urease at pH 7 and 20 degreesC. The removal of urea using urease-immobilized dialyzer was demonstrated with in-vitro dialysis and showed faster removing rate of urea than a regular dialyzer by 2.7 times.     

Human surfactant protein a suppresses T cell-dependent inflammation and attenuates the manifestations of idiopathic pneumonia syndrome in mice

We have previously shown an association between growth factor-induced upregulation of surfactant protein (SP)-A and suppression of alveolar inflammation in our murine model of donor T cell-dependent lung dysfunction after bone-marrow transplantation, referred to as idiopathic pneumonia syndrome (IPS). We hypothesized that SP-A protects the lung in vivo from IPS injury by downregulation of alveolar inflammation. Human SP-A (100 microg), purified by n-butanol extraction or preparative isoelectric focusing, was transtracheally instilled on Day 4 after BMT during a time of in vivo donor T-cell activation. At 48 h after treatment, immunohistochemical staining of lung sections showed that SP-A did not alter T cell- dependent cellular infiltration. However, macrophages from SP-A-instilled mice were less injured and spontaneously produced less tumor necrosis factor-alpha than did cells from buffer-instilled mice. Although exogenous SP-A did not significantly alter bronchoalveolar lavage fluid (BALF) high levels of total protein (TP), an inverse correlation between BALF SP-A and TP concentrations (r = -0.65; P = 0.02) was observed in SP-A-treated but not in buffer-instilled mice. The only difference between the effects of the two sources of SP-A was that butanol-extracted SP-A, but not isoelectric focusing-purified SP-A, suppressed the interferon-gamma/nitric oxide pathway. We conclude that SP-A downregulates T cell-dependent alveolar inflammation by multiple pathways leading to decreased IPS injury.     

聚醚型聚氨酯材料表面纤维蛋白原的吸附性研究

本文采用放射性同位素标记的方法研究了嵌段聚醚型聚氨酯在纯纤维蛋白原溶液中和稀释血浆中的表面纤维蛋白原吸附性规律，考察了聚醚型聚氨酯的特性粘数及溶液体系中的ＮａＣｌ浓度对材料表面纤维蛋白原吸附性的影响，结果表明，随着聚合物特性粘数的增大，材料表面的纤维蛋白原吸附量呈降低的趋势；溶液体系中盐浓度的降低导致纤维蛋白原凝固性增强，在纯纤维蛋白原溶液中，材料表面纤维蛋白原的吸附量相应增多，而在稀释血浆中，纤维蛋白原的吸附量相应减少，在达到最低值后又有上升的趋向，表明纤维蛋白原在材料表面的吸附还受血浆中其它大分子的影响。     

Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini- chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re- arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini- chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.      

脑内源性β-内啡肽对应激诱发促肾上腺皮质激素和催乳素释放的调节

在预先埋植第三脑室导管和预置颈外静脉导管的SD大鼠中,脑室内微量注射β-内啡肽抗血清,并与脑室内注射正常兔血清的大鼠对比。看到注射β-内啡肽抗血清后,ACTH和催乳素因限制性应激的释放,分别被抑制了46.1％和71.2％。说明中枢内源性β-内啡肽可能是ACTH和催乳素在某种应激时相伴释放的重要调节因素之一。     

不同导联系统记录体表心室碎裂电位效果对比研究

本文分别应用标准１２导联系统，Ｆｒａｎｋ正交导联系统和改良Ｆｒａｎｋ正交导联系统记录健康人３６例、陈旧性心肌梗塞４２例的心室碎裂电位，通过分析这些导联系统中相互垂直或近似垂直的导联上ＶＦＰ的形态，数量关系，发现改良Ｆｒａｎｋ正导联系统记录ＶＦＰ较其它导联系统更科学，合理，且操作方便。     

CM1 ligation initiates apoptosis in a caspase 8-dependent manner in Ramos cells and in a mitochondria-controlled manner in Raji cells

Burkitt lymphoma (BL) is a tumor with the characteristics of germinal center B cells. We previously reported that the CM1 (centrocyte/-blast marker 1) molecule is expressed only in germinal center B cells, specifically, in a subpopulation of centroblasts and centrocytes. In the present study, we investigated the apoptosis induced by anti-CM1 in the Ramos and Raji human BL cell lines. The Ramos is protected from apoptosis by the crosslinking of sIgM and the calcium ionophore by the ligation of CD40 with anti-CD40 monoclonal antibodies (mAb) or soluble CD40 ligand (sCD40L). In this investigation on the effect of CM1 on apoptosis in BL cell lines, we found that cellular signaling by CM1 induces apoptosis and decreases cell viability, in BL cell lines cultured for 24 hours with protein-G agarose beads conjugated anti-CM1 mAb. Stimulation by CD40 ligated with sCD40L protected Raji cells from CM1-induced apoptosis, but did not protect Ramos cells. Furthermore, after anti-CM1 mAb stimulation, CD95 expression was upregulated and CD40 expression was unaltered or slightly decreased in Ramos cells, whereas CD95 was downregulated and CD40 was slightly upregulated in Raji cells. The engagement of CD40 by sCD40L enhanced CD95 expression, but the level of CM1 expression was unchanged in Ramos. However, sCD40L downregulated both CD95 and CM1 expression in Raji. In addition, the caspase-8 specific inhibitor blocked CM1-induced apoptosis in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization was observed only in Raji cells. Moreover, the effector caspase inhibitor, z-DEVD, blocked CM1-mediated apoptosis in both cell lines. We found that CM1-induced apoptosis is achieved via different initiation pathways, which are cell-type dependent.