内皮细胞条件培养液诱导单核细胞分化为内皮细胞的实验研究

目的研究ECV-304条件培养液诱导单核细胞分化为内皮细胞的可能性.方法贴壁法分离培养外周血单核细胞并进行鉴定.用购买的ECV-304细胞株制备条件培养液和M-CSF诱导单核细胞分化,观察细胞形态变化,收集细胞,用免疫组化与异植物血凝素结合试验鉴定.结果获得的单核细胞具有CD14阳性细胞占84.3%;刺激一周后的单核细胞形态发生改变并且Ⅷ因子、异植物血凝素结合试验阳性.结论 ECV-304条件培养液能诱导单核细胞分化为内皮细胞,提示内皮细胞来源的一条途径.     

Feeding and selection of saccharin after injections of bombesin, LiCl, and NaCl

Rats injected with bombesin of LiCl showed similar suppression of food-deprivation-induced liquid diet intake, but only rats receiving LiCl avoided water-deprivation-induced consumption of a novel saccharin solution paired with injection. The data demonstrate that bombesin reduces feeding but does not induce conditioned aversion, and suggest that bombesin does not act to suppress food intake by production of gastrointestinal malaise.     

Lipophosphoglycan Antigen Shedding By Leishmania Donovani

ABSTRACT. The biochemical characterizations of lipophosphoglycans from various Leishmania species reported by other workers may or may not contain several types of lipophosphoglycan molecules. This is the first report in which a specific lipophosphoglycan has been defined by both its antigenie and electrophoretic properties. Furthermore, a purification procedure for this specific lipophosphoglycan is described and some biochemical characterizations are presented. Phospholipase C and the so-called phosphatidylinositol-specific phospholipase C of Bacillus cereus convert the amphipathic form of the lipophosphoglycan antigen to the hydrophilic form. Under equivalent incubation conditions, other phospholipases tested were not effective in conversion of the amphipathic to the hydrophilic form. Since the amphipathic form is present in conditioned media, antigen shedding cannot be explained by phospholipase C digestion of the amphipathic form, which would result in the release of only the hydrophilic form into the medium. Both the pellet and the supernatant fractions of conditioned media contained both forms of the antigen and did not differ in the relative amounts of the two. This observation rules out membrane blebbing as the major mechanism for the release of the amphipathic form.     

Estimating primate divergence times by using conditioned birth-and-death processes

The fossil record provides a lower bound on the primate divergence time of 54.8 million years ago, but does not provide an explicit estimate for the divergence time itself. We show how the pattern of diversification through the Cenozoic can be combined with a model for speciation to give a distribution for the age of the primates. The primate fossil record, the number of extant primate species, and information about the structure of the primate phylogenetic tree are combined to provide an estimate for the joint distribution of the primate and anthropoid divergence times. To take this information into account, we derive the structure of the birth-and-death process conditioned to have a subtree originate at a particular point in time. This process has a size-biased law and has an immortal line running from the root of the tree to the root of the subtree, with species on the spine having modified offspring and length distributions. We conclude that it is not possible, with this model, to rule out a Cretaceous origin for the primates.     

Cardiovascular component of the context signal memory in the crab Chasmagnathus

Research on diverse models of memory in vertebrates demonstrates that behavioral, autonomic and endocrine responses occur together during fear conditioning. With invertebrates, no similar studies have been performed despite the extensive study of fear memory paradigms, as the context signal memory (CSM) of the crab Chasmagnathus granulatus, usually assessed by a behavioral parameter. Here, we study the crab’s CSM, considering both the behavioral response and the concomitant neuroautonomic adjustments resulting in a heart rate alteration. Results show that upon the first presentation of the visual danger stimulus, a heart arrest followed by bradycardia is triggered together with a conspicuous escape response. The latter declines throughout training, while heart arrests become sporadic and bradycardia tends to deepen along the session. At test, 24 h after training, the outcome clearly contrasts with that shown at training, namely, stimulus presentation in the same context induces lower escape, no heart arrests and quick suppression of bradycardia. These results support the view that the same memory process brings about the changes in both responses. High escape, heart arrest and bradycardia are considered three parameters of the unconditioned response while minor escape, no heart arrests and bradycardia attenuation are three parameters of the learned response.     

Increased conditioned immobility and weight loss in rats following mechanical impacts to the skull that do not produce loss of consciousness

Rats either received a single vertical impact (15 km/h) of mechanical energy to their right dorsal skulls over the parietal region or served as handled controls. About 50% of the rats appeared normal after the impact. Thirty days later there were conspicuous areas containing neurons with shrunken and darkly stained somas within the cortices beneath the impact site and within the amygdala and entorhinal cortices. These neurons, occupying an average total area that ranged from 0.50 mm² to 5 mm², were evident even in rats that showed no stunning following the impact. These neurons were not seen in control rats. Subsequent decreases in body weight for rats that received the impact (even with no obvious stunning) were attenuated by oral access to 10% glucose but not by treatment with acetaminophen or ketamine. The rats that sustained the impact also displayed increased immobility within settings with which an aversive stimulus had been associated. Post-impact injection with ketamine did not normalize this behaviour. These results show that quantitative changes in some neuronal soma remain weeks after a single impact of mechanical energy that is not associated with immediate changes in behaviour. Concomitant with these neuronal alterations was increased emotional responsiveness to contexts associated with a single aversive episode and transient decreases in body weights.     

Vasopressin's effects on acquisition and extinction of conditioned avoidance response to smoking

Lysine-8-vasopressin (LVP) 5 I.U. or NaCl was administered intranasally daily for 5 days in a double blind study to 14 women and 7 men volunteers, 30 minutes prior to aversive conditioning sessions designed to assist them to stop smoking. Subjects were asked to record the number of urges to smoke, the strength of their strongest urge to smoke and the number of cigarettes smoked on a daily basis. Adequate data was obtained from 17 subjects for the Lead-in (pretreatment) week and for the Treatment week. Of these, 10 continued to supply sufficient responses through the sixth week of follow-up. During the week of aversive conditioning those subjects receiving LVP smoked significantly fewer cigarettes than the saline treatment group (p<0.01). During the Follow-up period the LVP group had significantly more urges to smoke than the saline group (p<0.01). The LVP group also smoked significantly more cigarettes than the saline group 4 weeks (p<0.05) and 6 weeks (0.01) after the Treatment week. LVP was associated with a facilitation of the acquisition of the avoidance response to smoking followed by an apparent acceleration of the extinction of the avoidance response compared to saline.     

Neurochemical changes associated with the action of acute administration of diazepam in reversing the behavioral paradigm conditioned emotional response (CER)

Neurotransmitter turnover of biogenic monoamines (dopamine, norepinephrine, and serotonin) and amino acids (glutamate, aspartate, and gamma-aminobutyric acid) was evaluated in rats exposed to the conditioned emotional response (CER) paradigm in the absence (total suppression) or presence of acute 5 mg/kg i.p. diazepam (which reversed suppression and restored normal responding). Based on previous studies of CER, with controls for shock and stimulus histories, the results with respect to the anxiolytic could be divided into several categories: changes in turnover which are associated only with the CER behavior; changes associated only with the drug, diazepam; changes which augmented the effects of the behavior; or changes which were the reverse of those associated with the behavior. Due to the multitude and complexity of the results, not all observations have clear explanations at this time. However, for the CER behavior per se, it is apparent that a combination of neurotransmitters, including some implications about acetylcholine, act in concert to bring about the behavioral suppression. The action of diazepam is more complex, involving the full spectrum of neurotransmitters to bring about its direct and indirect effects.In honor of Distinguished Professor Morris Herman Aprison     

Effects of an endothelial cell-conditioned medium on the hematopoietic and endothelial differentiation of embryonic stem cells

We have examined the effect of mouse bone marrow endothelial cell-conditioned medium (mEC-CM) on hematopoietic and endothelial differentiation of mouse embryonic stem cells (mESCs). mEC-CM can efficiently promote the differentiation of mESCs into Flk⁺ cells and hematopoietic colony-forming cells. mEC-CM proved to be as potent as a cytokine cocktail comprised of VEGF, bFGF, IGF and EGF. After inducing mESCs with mEC-CM, cobblestone-like cells were mechanically selected and identified which had the ability to incorporate DiI-Ac-LDL. DiI-Ac-LDL-positive cells were endothelial-like cells due to their expression of CD31 and Flk1, ability to bind to UEA1 and capacity to form capillary-like tube structures on matrigel. In conclusion, mEC-CM can efficiently promote the differentiation of mESCs into endothelial cells and hematopoietic colony-forming cells. The differentiated endothelial-like cells can be isolated by using DiI-Ac-LDL labeling and mechanical selection.     

Effect of Co-culturing both placenta-derived mesenchymal stem cells and their condition medium in the cancer cell (HepG2) migration,damage through apoptosis and cell cycle arrest

Human placental-derived mesenchymal stem cells (hPMSCs) are a promising candidate to inhibit the proliferation of hepatocellular carcinoma (HCC) cell lines such as HepG2. The effects of hPMSCs and their conditioned media on HepG2 are, however, still a mystery. As a result, the goal of this study was to look into the effects of hPMSCs and their conditioned media on HepG2 and figure out what was going on. Fluorescence-activated cell sorting and the MTT test were used to determine the percentage of cells that died (early apoptosis, late apoptosis). The DIO and DID colors were used to detect cell fusion and cell death in both cells. HepG2 cells were co-treated with hPMSCs or hPMSCs-conditioned medium (hPMSCs-CM) to reduce growth and promote apoptosis. Morphological changes were also seen in the 30 percent, 50 percent, and 60 percent cases. The secretion of cytokine was determined by the ELISA. Flow cytometry, caspase 9 immunofluorescence, qPCR (detection of Bax, Bcl-2, and β-catenin genes), western blot, and immunophenotyping revealed that treatment with hPMSCs or hPMSCs-CM caused HepG2 cell death through apoptosis (detection of caspase 9, caspase 3 protein). HepG2 cell cycle arrest could be induced by hPMSCs and hPMSCs-CM. Following treatment with hPMSCs or hPMSCs-CM, HepG2 cell development was stopped in the G0/G1 phase. These treatments also inhibited HepG2 cells from migrating, with the greatest effect when the highest ratio/concentration of hPMSCs (70%) and hPMSCs-CM were used (90%). Our findings indicated that hPMSCs and hPMSCs-CM could be promising treatment options for liver cancer. To elucidate the proper effect, more research on liver cancer-induced rat/mice is needed.