An effective method for quantitative evaluation of proteins adsorbed on biomaterial surfaces

An effective method for the quantitative evaluation of proteins adsorbed on biomaterial surfaces has been developed. First, the kinetic behavior of a range of human fibrinogen (Fib) adsorbed onto polystyrene (PS) films was investigated by using a reflectometry interference spectroscopy setup. The specific molecular number of adsorbed proteins, N(p,) was then defined. According to the definition, the numbers of Fib molecules adsorbed on PS films were calculated. An atomic force microscope (AFM) was used to scan the lateral distribution of the Fib molecules adsorbed on the PS films. From the AFM images, the practical specific molecular numbers were obtained by direct counting of the molecules. In order that the adsorbed number of Fib molecules on a unit area of the PS films could be counted easily, the solution concentration of proteins was reduced to 5 ag/mL (10(-18)g/mL). There was good consistency between the numbers calculated with the formula defined by us and the numbers counted from AFM images. Therefore, the results of the present study prove the validity of our definition of the specific molecular number of adsorbed proteins and the effectiveness of the reflectometry interference spectroscopy-based method for quantitative evaluation of adsorptive proteins.     

Neuroendocrine changes in colon of mice with a disrupted IL-2 gene

Neuroendocrine peptides have a variety of physiological functions in the gastrointestinal tract. This study was carried out to investigate the impact of IL-2 deficiency on the neuroendocrine system in normal colon, and the neuroendocrine changes during colonic inflammation. Mice with homozygous disrupted IL-2 gene (IL-2-/-) spontaneously developed a bowel disease with similarities to human ulcerative colitis. Different types of colonic endocrine cells and myenteric nerves were analysed in the IL-2-/- mice using immunomorphometry. The neuropeptide contents in the colonic tissues were determined by radioimmunoassay. Age-matched healthy IL-2+/- and IL-2+/+ mice served as controls and the colonic IL-2 levels were compared between these two groups of mice by ELISA. Our data showed that less than half the amount of IL-2 was synthesized in the colon of IL-2+/- mice compared with the IL-2+/+ wild-type mice. Two major differences in the neuroendocrine colon were found between the mice with an intact and disrupted IL-2 gene. One was age-related. The frequencies of various endocrine cells and myenteric nerves increased with age in the IL-2+/+ mice. However, no such increases were seen in the mice with a disrupted IL-2 gene. Instead, the volume densities of enteroglucagon, serotonin cells and substance P (SP), vasoactive intestinal polypeptide (VIP) and total myenteric nerves were lower in the older IL-2+/- and IL-2-/- mice compared with the wild type. The other was disease-related. Polypeptide YY (PYY) cells and tissue levels of PYY, SP and VIP were significantly decreased in the IL-2-/- mice during the course of bowel inflammation compared with the healthy IL-2+/- and IL-2+/+ controls. These findings indicate that colonic neuroendocrine alterations did occur in the mice with a disrupted IL-2 gene and diminished local IL-2 level, suggesting a role of IL-2 in the regulation of the neuroendocrine system and a prevalent interaction between the immune and neuroendocrine systems in normal colon. On the other hand, there were some changes that seemed to correlate with the bowel inflammatory process. They might be associated with the impaired function in inflamed gut and contribute to the development and/or prolongation of disease.     

大鼠烫伤后早期肝细胞变化的超微结构观察及形态计量分析

用超微结构形态计量方法分析了大鼠30％烫伤后早期肝细胞超微结构的变化规律。烫伤后,肝细胞内精原迅速减少,至6小时,几乎全部消失。烫伤后2小时、6小时。肝细胞内溶酶体的体积密度、数目密度和平均体积均明显增大。线粒体于烫伤后半小时出现基质密度增加、嵴扩张,烫伤后2小时、6小时,线粒体肿胀,其体积密度、平均体积增大。实验结果提示:在严重烧伤后数小时内,肝细胞的超微结构即出现明显的改变。本文对出现这些变化的机制进行了讨论。     

Gene therapy of cancer based on interleukin 12

Tumor formation and growth depends mainly on the inability of the organism to elicit a potent immune response, and on the formation of new blood vessels that enable tumor nutrition. Interleukin-12 (IL-12) therapy can target both processes. And IL-12-based gene therapy may restrict IL-12 production to the relevant site in order to obtain enhanced antitumor activity and reduced toxicity. In the clinical setting, IL-12 gene transfer can be used either to improve the pharmacokinetic/pharmacodynamic profile of the cytokine, to transduce dendritic cells or to enhance the efficiency of antitumor vaccination. It can also synergize with other procedures involving the simultaneous transfer of other transgenes or non-gene based strategies. The strong anti-tumoral power shown in many different animal models has not been found in early clinical trials in which cancer patients were treated by peritumoral injections of autologous fibroblasts producing IL-12, intratumoral injections of an adenoviral vector encoding human IL-12 genes, or intratumoral injection of autologous dendritic cells transduced ex vivo with this same adenoviral vector. However, these trials have set the proof-of-concept that local production of IL-12 inside a tumor can stimulate tumor infiltration by effector immune cells and that in some cases it is followed by tumor regression. From the many questions that arise after these disappointing results the most relevant concerns the duration and intensity of transgene expression and the capability to monitor this topics in vivo. New vectors that might achieve regulated, long-term production of this cytokine might have better results and merit clinical testing.     

Analysis of Electromagnetic Exposure in Wireless Power Transfer System for Endoscopic Micro-robot

A wireless power transfer system for endoscopic micro-robot operating at 36 kHz is presented in this paper. The issue of patient＇ s health and safety regarding exposure to the electromagnetic field is addressed. The specific absorption rate and current density can be used to investigate the electromagnetic influences on the biological tissues surrounded by the wireless power launching coil. In view of this purpose, the limited close-ound solenoid electromagnetic model is built, the relationship between the electric intensity and the specific absorption rate and current density is deduced, and the simulation experiments are done. Experimental results show that the values of SAR and current density related to different tissue catalogs are all very small and do not exceed their own limits respectively when the resonance frequency of operation is 36 kHz.     

Testicular metastasis of primary cecal carcinoid tumor

Testicular carcinoids are rare and the majority are of primary testicular origin. Testicular carcinoids can also be secondary from extra-testicular primary tumors, but the incidence is even less common. The case described here is a patient who initially had an infiltrating cecal carcinoid with hepatic metastasis. Following surgery, he was managed with octreotide and had close monitoring of the levels of serum serotonin and its urinary metabolite. He experienced a fairly indolent clinical course and 5 years after excision of the primary cecal carcinoid, his hepatic lesion has virtually been unchanged. However, he developed a secondary testicular metastasis. He has otherwise remained well, without evidence of metastases elsewhere on imaging studies.     

Divergent effects of prostaglandin receptor signaling on neuronal survival

Induction of cyclooxygenase-2 (COX-2) with production of prostaglandins occurs in a wide spectrum of acute and chronic neurodegenerative diseases and is associated with neuronal death. Inhibition of the COX-2 pathway and downstream production of prostaglandins protect neurons in rodent models of cerebral ischemia and neurodegeneration. Recent studies investigating the functions of selected prostaglandin receptor pathways in mediating COX-2 neurotoxicity have demonstrated both toxic and paradoxically neuroprotective effects of several receptors in models of excitotoxicity. In this study, we investigate the functions of additional prostaglandin receptors not previously characterized in organotypic models of glutamate excitotoxicity. We find that PGD₂, PGI₂, and PGF_2α receptors protect motor neurons in an organotypic spinal cord model of amyotrophic lateral sclerosis (ALS). In addition, PGI₂ and TXA₂ receptors rescue CA1 neurons in an organotypic hippocampal model of N-methyl-d-aspartate excitotoxicity. However, in a model of inflammation induced by lipopolysaccharide, prostaglandin receptors previously found to be protective in excitotoxicity now cause CA1 neuronal death. Taken together, these studies identify novel eicosanoid receptor signaling pathways that mediate neuronal protection in excitotoxic paradigms; these data also support the emerging hypothesis that the toxic/protective effects of eicosanoid signaling on neuronal viability diverge significantly depending on whether excitotoxicity or inflammation predominates as the underlying toxic stimulus.     

Locomotion defects, together with Pins, regulates heterotrimeric G-protein signaling during Drosophila neuroblast asymmetric divisions

Heterotrimeric G proteins mediate asymmetric division of Drosophila neuroblasts. Free Gbetagamma appears to be crucial for the generation of an asymmetric mitotic spindle and consequently daughter cells of distinct size. However, how Gbetagamma is released from the inactive heterotrimer remains unclear. Here we show that Locomotion defects (Loco) interacts and colocalizes with Galphai and, through its GoLoco motif, acts as a guanine nucleotide dissociation inhibitor (GDI) for Galphai. Simultaneous removal of the two GoLoco motif proteins, Loco and Pins, results in defects that are essentially indistinguishable from those observed in Gbeta13F or Ggamma1 mutants, suggesting that Loco and Pins act synergistically to release free Gbetagamma in neuroblasts. Furthermore, the RGS domain of Loco can also accelerate the GTPase activity of Galphai to regulate the equilibrium between the GDP- and the GTP-bound forms of Galphai. Thus, Loco can potentially regulate heterotrimeric G-protein signaling via two distinct modes of action during Drosophila neuroblast asymmetric divisions.     

125I-白细胞介素-8在小鼠体内的分布研究

为了解白细胞介素 - 8的体内行为 ,用 Bolton- Hunter法对 IL- 8进行 1 2 5I标记 ,并测定它在小鼠体内的分布 ;得到了 1 2 5I- IL- 8在小鼠血、心、肝、肺、肾、骨、脾等脏器中的分布以及它在血液中的快相半排期 T1 /2α为 0 .3 2 h和慢相半排期 T1 /2β为 8.0 1h。1 2 5I- IL- 8主要通过肾排除