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1.
GA 12-aldehyde obtained from mevalonate via ent-kaurene, ent-kaurenol, ent-kaurenoic acid and ent-7α-hydroxykaurenoic acid in a cell-free system from immature seeds of Cucurbita maxima was converted to GA 12 by the same system. When Mn 2+ was omitted from the system GA 12-aldehyde and GA 12 were converted further to several products. Among these GA 15, GA 24, GA 36 and GA 37 were conclusively identified by GC-MS. With the exception of GA 37 these GAs have not previously been found in higher plants. Another biosynthetic pathway led from ent-7α-hydroxykaurenoic acid to very polar products via what was tentatively identified as ent-6α, 7α-dihydroxykaurenoic acid. An unidentified component with an MS resembling that of a dihydroxykaurenolide was also obtained from incubations with mevalonate. 相似文献
2.
The effect of different prostaglandins and prostaglandin-metabolites on the growth and differentiation of Friend erythroleukemia cells (FLC) was evaluated. The prostaglandin-metabolites, thromboxane B 2 and 6-keto PGF 1α, were completely inactive, while PGE 1 inhibited slightly and PGF 2α stimulated the replication of FLC. PGA 1 was found to be the most active compound. It profoundly inhibited the replication of both DMSO-treated and undifferentiated FLC. Most importantly, PGA 1 alone induced differentiation in FLC, stimulating hemoglobin production over a five-day period. PGA 1-stimulated differentiation was completely suppressed by the addition of 10 −6M hydrocortisone. Finally, treatment of DMSO-differentiated cells with PGA 1 (but no DMSO) prevented the return to the undifferentiated state. 相似文献
3.
Summary The expression of the intermediate filament protein, vimentin, was studied in skeletal muscle during a cycle of degeneration
and regeneration. Venom from the Australian tiger snake, Notechis scutatus scutatus, was used to initiate the breakdown of the soleus muscle of young, mature rats in vivo. Cryosections and Western blots of muscle samples were labelled using antibodies to vimentin, and examined at fixed time
points after venom injection. Vimentin was absent in control adult muscle fibres, but was identified in activated satellite
cells 12 h after venom assault. The amount of this protein rose during the early stages of regeneration, reaching its peak
at 2–3 days. At this time, the expression of muscle-specific intermediate filament protein, desmin, began. As the abundance
of desmin increased with the maturation of the regenerating myofibres, the abundance of vimentin declined until it was no
longer detectable in mature regenerated fibres. It is suggested that vimentin plays an important role during satellite cell
activation in the early stages of regeneration, and that the expression of vimentin may act as a stimulus for the expression
of desmin at later stages of regeneration. 相似文献
4.
Aqueous solutions of highly stable supramolecular donor–acceptor complexes of chemically nonmodified pristine C 60 fullerene molecules with H 2O molecules (hydrated C 60 fullerene–C 60HyFn) and their labile nano-sized clusters were examined for their antioxidant effects on removal of hydroxyl radicals (OH) and protecting DNA against oxidative damage induced by ionizing radiation in vitro. The suppressing influence of C 60HyFn on the formation of OH-radicals in water exposed to X-rays at doses of 1–7 Gy was assessed by determination of oxidation levels of coumarin-3-carboxylic acid. C 60HyFn demonstrates apparent antiradical activity in vitro in the range of concentrations of 10 −11–10 −6 M. Paradoxically, the OH-removing efficacy of C 60HyFn was in reverse correlation with fullerene concentration. It was hypothesized that the antiradical action of C 60HyFn in water medium generally is due to a “nonstoichiometric” mechanism, supposedly to a hydrated free radical recombination (self-neutralization), which is catalyzed by specific water structures ordered by C 60HyFn. With the use of 8-oxoguanine as a marker of oxidative damage to DNA, it has been demonstrated that C 60HyFn in concentrations of 10 −7–10 −6 M protects nucleic acids against radical-induced damage. The second part of the present study was aimed to evaluate the overall radioprotective efficacy of C 60HyFn in doses of 0.1 or 1 mg/kg b.w. injected intraperitoneally to mice either 1 h before or 15 min after lethal dose exposure of the X-ray (7 Gy) irradiation. Survival rate of the mice was observed at 30 day intervals after irradiation, while the weight gains of experimental animals were monitored as well. The most significant protective effect was demonstrated when 1 mg/kg dosage of C 60HyFn was administered before irradiation. The outcome of the substance testing is 15% survival rate of irradiated animals at 30 days of observation, and prevention of noticeable weight loss characteristic for radiation impact, versus unprotected control animals. In conclusion, results of the study obviate that the apparent protective action of C 60HyFn in vivo is determined by its considerable ability to decrease X-ray-generated reactive oxygen species. Based on the results and that neat C 60 is nontoxic, actually in the hydrated form, without side effects and with sufficient radioprotective effects in low doses, C 60HyFn may be considered as a novel antioxidant agent, which substantially diminishes the harmful effects of ionizing radiation. 相似文献
5.
Spontaneous and evoked secretion of acetylcholinesterase from the hippocampus in vivo has been demonstrated by the use of push-pull cannulae. Local perfusion with 10 −5M carbachol evoked an increase of 104% in acetylcholinesterase release with no accompanying change in butyrylcholinesterase or lactic dehydrogenase. Local or systemic atropine sulphate blocked the carbachol-evoked increase in acetylcholinesterase release, whilst gallamine had no effect. Local perfusion of γ-aminobutyric acid (10 −4M) also blocked the carbachol-evoked release of acetylcholinesterase but had no effect on the spontaneous release. It is concluded that a soluble form of acetylcholinesterase is secreted from the hippocampus in response to stimulation of muscarinic receptors; this secretion can be influenced by γ-aminobutyric acid, which is present in interneurones in the hippocampus. 相似文献
6.
To determine if hormone-induced events leading to ovulation an granulosa cell luteinization might be associated with changes in the surface configuration of granulosa cells we have studied the morphology of granulosa cells from the preovulatory follicles both in vivo and in vitro. In vivo, granulosa cells in follicles from rats primed with estradiol and FSH developed bulbous protrusions termed blebs in response to injected hCG. The blebs were restricted to the adluminal granulosa cells which possess the least number of receptors for hCG. When granulosa cells from follicles of rats primed with estradiol and FSH were cultured in vitro, in the absence of serum, approximately 10% of the cells formed blebs. In the presence of 10% rat or fetal calf serum, nearly 90% of the cells formed blebs by 18 hr. Serum-induced bleb formation was prevented by 1 mM dibutyryl cycle-AMP plus 0.5 mM methyl isobutyl xanthine and by cytochalasin B (25 mug/ml), while 0.1 muM colchicine had no effect. Fibronectin at 25 mug/ml increased bleb formation three-fold over control values in serum-free medium. When hCG was included in serum containing medium, the majority of the cells remained smooth without any blebs. Thus, in contrast to its action in vivo, hCG inhibited the formation of blebs in vitro. When the cells incubated in the presence of dbcAMP plus methyl isobutyl xanthine in serum-containing medium, none of the cells formed blebs. One explanation for the seemingly opposite actions of hCG in vivo and in vitro is that hCG might act to alter the permeability of the pre-ovulatory follicles, and thereby allow the admission of serum. The admitted serum component(s) could then induce the formation of blebs on receptor-deficient adluminal cells that did not have elevated cAMP concentrations. The results suggest that fibronectin and/or other serum components, act to induce microfilament-dependent, cAMP-inhibited bleb formation on granulosa cells in vivo and in vitro. 相似文献
7.
Twenty five patients booked for induction of labour, at 38 weeks or more gestation, were administered a controlled release vaginal polymer pressary containing 10mg prostaglandin E 2(PGE 2), designed to release 0.6mg per hour in vivo. The release profile from the polymer was linear throughout the eight hour observation period with a correlation coefficient of 0.81, and regression slope of 0.93 mg/hr. with 95% confidence intervals of 0.63mg/hr. to 1.23 mg/hr. This compared with a concomitatnt release profile in vitro which was uniform with time for the first five hours, but then continued at a decreasing rate with a correlation coefficient of 0.98. The relationship between PGE 2 release and cervical score change was linear, with a correlation coefficient of 0.65. The results show that PGE 2 release from the pessary in vivo is predictable, and suggest that the controlled release pessary offers the advantages of greater control of cervical ripening than alternative vehicles currently available. 相似文献
8.
Summary Immunoreactive alpha-transforming growth factor (-TGF) was shown by immunocytochemistry to be present in the rat mammary gland at various stages of development, the staining being most intense in mature myoepithelial cells. -TGF was also detected in the secretions of the mammary glands of pregnant and lactating rats. -TGF in the extracts of rat mammary glands at each stage of development, and in several rat mammary cell lines and in culture medium in which they had been grown, was shown by Western blotting to consist primarily of a protein of molecular weight 50 kDa. The amount of this protein was greater in the mammary gland of the lactating rat than in resting or involuting glands. -TGF was also found in some, but not all, human breast carcinomas, and in benign hyperplastic breast diseases. 相似文献
9.
Autoradiographic studies were carried out on regenerating muscles of adult chickens. Three different muscles of hens were injured, and tritiated thymidine (1 μCi/g) was injected at various times after injury to label replicating muscle precursors. Detailed comparisons of grain counts over premitotic nuclei in samples removed one hour after injection of tritiated thymidine, and of postmitotic myotube nuclei in samples removed 10 days after injury (when labeled precursors had fused to form myotubes), revealed how many times some labeled precursors had divided before fusing into myotubes. DNA synthesis in muscle precursors was initiated 30 h after injury. Grain counts of myotube nuclei indicated that many muscle precursors labeled at the onset of myogenic cell proliferation had divided only once, or twice, before fusing into myotubes. The relationship of these in vivo results to the cell lineage model of myogenesis is discussed. 相似文献
10.
The promoters, PTH4 and P-TH270 involved in the regulation of Streptomyces coelicolor differentiation were subcloned into Streptomyces promoter, i.e. probe plasmid pIJ4083, and the recombinant plasmids, pIJ4470 and pIJ4471, were constructed. Two promoters could drive the expression of reporter gene encoding catechol dioxygenase when pIJ4470 and pIJ4471 were introduced into some white mutants (C85, C70, C71, C17 and C119). The total RNA was isolated from these strains containing recombinant plasmid. Probes were prepared by labelling 5 -ends of PTH4 AND PTH270 DNA fragments using radioisotope. DNA - RNA hybridization was carried out with the probes and RNAs isolated from different strains. The S1 mapping result showed that all RNAs from strains of C85/pIJ4470, C85/4471, C70/pIJ4470, C70/pIJ4471 and C17/pIJ4470 as well as C17/pIJ4471 gave rise to strong positive hy-bridization signal, whereas RNAs from C71/pIJ4470 and C71/pIJ4471 did not give any positive signal. RNAs from C119/pIJ4470 and C119/pIJ4471 gav 相似文献
11.
目的探讨国产西罗莫司与原研品对移植宿主外周血中免疫细胞的影响效果。方法体外实验:人膀胱癌T24细胞体外培养,分别加入国产西罗莫司和原研品,CKK-8法检测并比较细胞增殖活性受抑制的情况。体内实验:建立小鼠异位心脏移植模型,设立对照无手术组(对照组)、移植无治疗组(Tx组)、移植+国产西罗莫司组(Tx+YXK组)、移植+原研品组(Tx+RAPA组)。观察移植心脏搏动情况,受者脾脏的流式细胞学检测,以及脾脏及移植物中免疫细胞浸润的病理检查。流式细胞检测树突状细胞(DC),CD8+细胞和调节性T细胞(Treg),病理组织学检测及免疫组化染色比较两组免疫细胞浸润情况。两组间比较采用独立样本t检验,多组间比较采用单因素方差分析,两两比较采用LSD-t检验。结果体外实验结果显示,国产西罗莫司与原研品对T24细胞活力影响的差异无统计学意义(P>0.05)。体内实验结果显示,Tx组移植心脏于第7天停止搏动,Tx+YXK组和Tx+RAPA组在第10天心脏搏动仍有力、节律正常。(1)脾脏流式细胞检测显示,与对照组、Tx组比较,Tx+RAPA组、Tx+YXK组CD11c+I-A+CD86+DC细胞(15.88±4.73、22.90±3.86比4.51±1.57、5.40±2.54)、CD8+淋巴细胞数量(6.32±0.98、6.75±1.34比3.03±1.12、3.23±0.97)均降低,而Tx+RAPA组CD4+CD25+Foxp3+阳性细胞数量(15.06±3.42比7.87±1.95,10.88±2.08)升高(P均<0.05)。Tx+YXK组和Tx+RAPA组3种免疫细胞数量差异均无统计学意义(P>0.05)。(2)移植心脏病理免疫细胞组化染色灰度分析,Tx组、Tx+YXK组和Tx+RAPA组CD4,CD8,IDO和CD11b数量差异无统计学意义(P>0.05),与Tx组比较,Tx+RAPA组和Tx+YXK组CD11c(25143.52±3525.12比12936.30±766.94、14240.60±3124.67)、Foxp3阳性细胞浸润数量(500.78±238.33比46.05±68.16、49.22±25.82)降低(P均<0.05),Tx+YXK组和Tx+RAPA组比较差异无统计学意义(P>0.05)。(3)模型动物脾脏病理免疫细胞组化染色灰度分析,Tx组CD 4和CD8阳性细胞浸润数量较Tx+YXK组和Tx+RAPA组少,但差异无统计学意义(P>0.05),Tx+YXK组和Tx+RAPA组比较,各种细胞染色的IOD值差异均无统计学意义。结论使用国产西罗莫司与原研品两种药物后受者移植心脏和脾脏中的细胞浸润变化一致;在体外对细胞增殖、移植后抗排斥作用和体内免疫细胞的影响表现均一致。 相似文献
12.
When aggregates of HM-1 embryonal carcinoma (EC) cells were exposed to 10(-6) M retinoic acid for 2 days and cultured in medium lacking retinoic acid, they differentiated to nerve cells, endoderm cells, and myoblasts. Cells 2 days after initial exposure to retinoic acid were not significantly different from the parental EC cells, as judged by cell-surface architecture and by reactivity to lectins. On the fourth day, the surface of the aggregates was covered with two kinds of cells distinguishable from the parental cells. The round cells with short villi seemed to be precursors to endoderm cells. Receptors for Dolichos biflorus agglutinin (DBA) newly appeared and receptors for peanut agglutinin (PNA) were still expressed on their surfaces. The other cells, which were round cells with a few processes, might be precursors to nerve cells. PNA receptors had disappeared from their surfaces, and DBA receptors were not expressed. On the sixth day of differentiation, possible precursors to myoblasts were detected; they were flat cells with smooth surfaces. These cells lacked cell-surface receptors for the two lectins, while the precursor cells and the myoblasts excreted intercellular fibers reacting with PNA. HM-1 cells synthesized much embryoglycan, the structure of which was similar to that of the glycan isolated from quasinullipotent F9 cells. The only difference was that the glycan from HM-1 cells lacked DBA binding sites. Synthesis of fucosylated embryoglycan mainly decreased between the second and fourth day of differentiation. As above, cell-surface changes occurred mainly between the second and fourth day. The period seems to be important in determining the fate of the cells, since endoderm cells were scarcely seen among differentiated cells which had been continuously exposed to 10(-6) M retinoic acid during the period. 相似文献
13.
Inflammatory liver diseases are associated with oxidative stress mediated particularly by neutrophilic granulocytes. At inflammatory loci, hypochlorous acid (HOCl) is generated by myeloperoxidase. HOCl reacts with a large variety of molecules and induces (among other reactions) the formation of lysophosphatidylcholine (LPC) from polyunsaturated phosphatidylcholines (PC).As liver tissue contains huge amounts of polyunsaturated PC species enhanced LPC concentrations are detectable under these conditions. However, human liver contains also major amounts of polyunsaturated phosphatidylethanolamine (PE). It is so far widely unknown, if PE oxidation by HOCl leads to the generation of LPE in a similar way as observed in the case of PC. Using MALDI-TOF mass spectrometry (MS) and 31P NMR spectroscopy, LPC generation from unsaturated PC could be verified in the presence of HOCl. In contrast, unsaturated PE led exclusively to chlorohydrins and other oxidation products but not to LPE.Although these data were obtained with a quite simple model system, it is obvious that LPC is a much more suitable biomarker of oxidative stress than LPE: LPC is more readily generated and also more sensitively detectable by means of mass spectrometry and other spectroscopic methods. Nevertheless, it will also be shown that the nitrile of LPE is also generated. However, this compound is exclusively detectable as negative ion. 相似文献
14.
The effects of prostacyclin (PGI 2) and its breakdown product 6-oxo-PGF 1α on various aspects of gastric function were investigated in the rat. PGI 2 increased mucosal blood flow when infused intravenously. PGI 2 was a more potent inhibitor of gastric acid secretion in vivo than PGE 2. Like PGE 2, PGI 2 inhibited acid secretion from the rat stomach in vitro. PGI 2 had comparable activity to PGE 2 in inhibiting indomethacin-induced gastric erosions. Thus prostacyclin shares several of the activities of PGE 2, and may be involved in the regulation of gastric mucosal function. 相似文献
15.
Autoimmune diseases that are resistant to conventional treatment cause severe morbidity and even mortality. In the present study we demonstrate that complete remissions can be achieved in refractory polychondritis and systemic lupus erythematosus (SLE), even at advanced stage, with the use of autologous stem-cell transplantation (SCT). Remissions persisted after reconstitution of the immune system. In the treatment of advanced systemic sclerosis (SSc), stable disease may be achieved with autologous SCT. 相似文献
16.
Prostaglandin (PG) and thromboxane B 2 (TXB 2) biosynthesis was studied in cultured astrocytes from neonatal rat brain hemispheres. After two weeks of cultivation, prostanoids were formed with the spectrum: PGD 2 > TXB 2 > PGF 2 > PGE 2, as measured by specific radioimmunoassays. Under basal conditions PGD 2 biosynthesis (9.55 ng/mg protein/15 min) was in the same order of magnitude as the sum of the other prostanoids. The formation of prostanoids was stimulated in a concentration dependent manner (up to 6–10 fold) by the calcium ionophore A 23187 (0.01–10 μM) as well as by melittin (0.01–5 μg/ml), phospholipase A 2 (10–40 U/ml) and phospholipase C (0.01–1 U/ml). Basal and evoked PG and TXB 2 biosynthesis depended on the availability of Ca 2+, as demonstrated in Ca 2+ free incubation medium containing Na 2EDTA (1 μM), or with verapamil (100 μM) and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)-octylester-HCl (TMB-8, 1–100 μM). Indomethacin (10 μM), mepacrine (100 μM) and p-bromophenacylbromide (50 μ M) inhibited basal and evoked PG formation. Thin-layer chromatography (TLC) detection after incubation of the cells with [ 3H]arachidonic acid (1 μCi/ml, for 60 min) confirmed the results obtained by radioimmunoassay. Incubation of [ 3H]arachidonic acid labelled cells with inonophore or phospholipases, followed by lipid extraction and TLC, showed that A 23187 liberated [ 3H]arachidonic acid predominantly from phosphatidylethanolamine, whereas phospholipase A 2 and C reduced mainly the labelling of the phosphatidyl-inositol/-choline fraction. Potassium depolarization of the cells did not enhance prostanoid formation. Similarly, drugs with affinity to - or β-adrenoceptors, or to dopamine-, 5-hydroxytryptamine-, muscarine-, histamine-, glutamate-, aspartate-, GABA, adenosine- and opioid-receptors failed to stimulate prostanoid biosynthesis. Also compounds like angiotensin, bradykinin and thrombin were ineffective in this respect. In conclusion, our results confirm that cultured astrocytes possess the complete pattern of enzymes necessary for prostanoid formation and hence might play a crucial role in brain prostanoid biosynthesis. Stimulation of prostanoid biosynthesis involves Ca2+-dependent activation of phospholipase A2, cyclooxygenase reaction and further PG metabolism. However, the endogenous stimulus for enhanced prostanoid synthesis in the brain still has to be established. 相似文献
17.
Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewal and multi-directional differentiation. Recent
reports showed that BMSCs could differentiate into endocrine cells of pancreas. However, the differentiation is not efficient
enough to produce insulin-producing cells for the future therapeutic use. Pdx-1 is a crucial regulator for pancreatic development. Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determine the effect of Pdx-1 expression on differentiation of BMSCs in vitro. The results showed that BMSCs could self-assemble to form functional pancreatic islet-like structures after differentiation
in vitro. The proportion of insulin-producing cells differentiated from Pdx-1 +BMSCs was 28.23%±2.56%, higher than that from BMSCs transfected with vacant vector and Pdx-1 − BMSCs (7.23%±1.56% and 4.08%±2.69% respectively) by flow cytometry. Immunocytochemical examination also testified the expression
of multiple β-cells-specific genes such as insulin, glucagons, somatostatin in differentiated BMSCs. The results also revealed
that the expressions of genes mentioned above in Pdx-1 +BMSCs were higher than that in Pdx-1 −BMSCs, which was confirmed by Western blotting analysis and RT-PCR. Glucose-induced insulin secretion from Pdx-1 +BMSCs in 5mmol/L and 25mmol/L glocuse was (56.61±4.82) μU/mL and (115.29±2.56) μU/mL respectively, which were much higher
than those from Pdx-1 −BMSCs((25.53±6.49) μU/mL and (53.26±7.56) μU/mL respectively). Grafted animals were able to maintain their body weight and
survive for relatively longer periods of time than hyperglycemic sham-grafted controls, which demonstrated an overall beneficial
effect of the grafted cells on the health of the animals. These findings thus suggested that exogenous expression of Pdx-1 should provide a promising approach for efficiently producing islet-like cells from BMSCs for the future therapeutic use
in diabetic patients. 相似文献
18.
量子点表面经生物分子或药物分子修饰而具有生物功能.功能化量子点具有独特的光学性质和生物相容性,在生物医学光学诊断和治疗领域具有广泛的应用.本文简要介绍了功能化量子点制备及修饰方法,综合评述了量子点在肿瘤活体诊断和治疗中的应用,包括活体淋巴结成像、血管动态成像、肿瘤成像和抗肿瘤药物示踪等,讨论了功能化量子点在肿瘤活体诊断和治疗中的应用前景以及面临的挑战. 相似文献
19.
Experiments were performed on two patients with custom-made instrumented massive proximal femoral prostheses implanted after tumour resection. In vivo axial forces transmitted along the prostheses were telemetered during level walking, single- and double-leg stance, and isometric exercises of the hip muscles. These activities varied the lever arms available to the external loads: minimum for double-leg stance and maximum for hip isometric exercises. Kinematic, force plate, EMG and telemetered force data were recorded simultaneously. The force magnification ration (FMR; the ratio of the telemetered axial force to the external force) was calculated. The FMRs ranged from 1.3 (during double-leg stance) to 29.8 (during abductors test), indicating that a major part of the axial force in the long bones is a response to muscle activity, the strength of which depends on the lever arms available to the external loads. From these results, it was shown that the bulk of the bending moment along limbs is transmitted by a combination of tensile forces in muscles and compressive forces in bones, so moments transmitted by the bones are smaller than the limb moments. It was concluded that appropriate simulation of muscle forces is important in experimental or theoretical studies of load transmission along bones. 相似文献
20.
The native gibberellin A 4 (GA 4), in radioactive form ([1,2- 3H]GA 4, 1.06 Ci/mmol), was fed to carrot somatic cell cultures (suspension and immobilized cell systems) and its metabolism over a 48 hr period was investigated. It was found that the [ 3H]GA 4 was metabolized to at least two GAs, [ 3H]GA 1 and [ 3H]GA 8, six GA glucosyl conjugates, [ 3H]GA 1-0(3)-glucoside, [ 3H]GA 1-0(13)-glucoside, [ 3H]GA 1-glucosyl ester, [ 3H]GA 4-glucoside, [ 3H]GA 4-glucosyl ester, a [ 3H]GA 8 glucosyl conjugate(s) and a previously unknown [ 3H]GA 1 glucosyl conjugate ([ 3H]GA 1-0(3,13)-diglucoside-like compound). The GA 1-diglucoside-like compound was found only in extracts of cells and was present in significant amounts (33 % of total extractable radioactivity). All other metabolites were present in both cells and medium. For extracts of the medium, no differences between the suspension and immobilized cultures existed in types of [ 3H]GA 4 metabolites although quantitative differences were apparent. 相似文献
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