Biomedical subjects
Publications and source records attributed to P Xia.
DCK lactam analogues were synthesized and evaluated for anti-HIV activity against HIV-1 replication in H9 lymphocyte cells. 4-Methyl-DCK lactam (11a) exhibited potent anti-HIV activity with EC50 and therapeutic index values of 0.00024 microM and 119,333, respectively.
New 4',5',2,3,4-substituted 2'-amino chalcones were synthesized and evaluated for cytotoxicity against a panel of human tumor cell lines. Several compounds displayed significant cytotoxicity. The most promising lead molecule (10) also had high activity toward multi-drug resistant KB-VIN, and ovarian 1A9 cell lines. 2'-Amino chalcones demonstrated significantly increased antitumor activity compared with the corresponding chalcones, while, the epoxide derivatives generally showed greatly reduced activity.
The objective of this study was to investigate the relationship between oocyte morphology and follicular fluid steroid concentrations in patients being treated with intracytoplasmic sperm injection. A total of 82 IVF cycles were evaluated in patients aged 24-40 years. Oocytes at metaphase II were graded into four groups according to the status of the first polar body and the size of the perivitelline space. The proportion of oocytes at the germinal vesicle and germinal vesicle breakdown stages, and the proportion of degenerated oocytes and oocytes with a large polar body were compared with different concentrations of oestradiol, progesterone and testosterone in the follicular fluid. The association between these oocyte characteristics and the ratio of oestradiol:testosterone and oestradiol:progesterone was also analysed. The results showed that oocyte morphology, as assessed by the status of the first polar body and the size of the perivitelline space, is associated with the ratio of oestradiol:testosterone and oestradiol:progesterone but not with the absolute concentrations of oestradiol, progesterone and testosterone in the follicular fluid. A ratio of oestradiol:testosterone > 200 is the best indicator for a small proportion of grade 1 and 2 oocytes (poor quality), a large proportion of grade 3 and 4 oocytes (good quality), and a small proportion of oocytes with cytoplasmic inclusions. These results will be of clinical use in evaluating oocyte quality.
OBJECTIVE: To establish a new method of detecting mycobacteria and their L-forms in blood. METHODS: 65 samples of peripheral blood from patients with pulmonary tuberculosis were cultivated directly or cultivated with hemolyzed-centrifugated blood sediments in 92-3TB and 92-3TBL liquid medium, and the cultures were staining with immunoenzyme technique (ABC method). RESULTS: In 65 specimens, the positive rates of mycobacteria and their L-forms were 15%, 26% respectively with total isolation rate of 32%. In cultivating with hemolyzed-centrifugated blood the positive rate was much higher than direct cultural method (P < 0.05). In sputum the positive rates of acid-fast bacilli and their L-forms were 38% and 20% respectively, with total isolation rate of 52%, higher than that in peripheral blood (P < 0.05), and the total positive rate of combinative detection of blood and sputum salmples was 65%. CONCLUSIONS: Mycobacteria and their L-forms exist in peripheral blood of patients with pulmonary tuberculosis, and mainly in L-forms. Cultivation with hemolyzed-centrifugated blood in liquid medium and staining with immunoenzyme technique are valuable in routine detection of mycobacteria and their L-forms in peripheral blood. The positive rate of bacterial culture of pulmonary tuberculosis could be increased in combination with sputum mycobacteria and their L-forms examination.
This study aimed to investigate the mechanism of Staphylococcus aureus' resistance to fluoroquinolones. The uptake of lomefloxacin, ofloxacin by Staphylococcus aureus and the effect of CCCP on the uptake were studied by the fluorescence method. The uptake of lomefloxacin, ofloxacin by sensitive organisms is higher than that by resistant organisms; CCCP had different influences on different organisms, but no significant difference between the effects of CCCP on sensitive strains and on resistant strains was noted. The uptake of lomefloxacin, ofloxacin by SA2-16 was much lower than that by SA2-16's parent, and after the addition of CCCP, the uptake of both quinolones by SA2-16 increased rapidly, but the concentration did not reach its parent's concentration in stable condition. These results indicate that the decreasing of the uptake of fluoroquinolones is one of the mechanisms responsible for Staphylococcus aureus to resistance fluoroquinolones, and as a mechanism of resistance to drugs, it plays different roles in different strains.
AIM: To investigate a feasible synthetic procedure of droloxifene and study on its new bioactivities. METHODS AND RESULTS: Droloxifene was synthesized using methoxybenzene and phenylacetic acid as starting materials, via Friedel-Crafts acylation, alkylation, demethylation, etherification, Grignard addition, elimination-dehydration, conversing configuration and forming citrate, totally 8 steps, overall yield 14.7% (9.2%). By pharmacological test, droloxifene citrate shows two new bioactivities: (1) obvious effect on reversing the MDR of K562/A02 cells and modulating mdrl, GST pi and TopoII alpha expression. (2) inducing apoptosis in cultured rat luteal cell. CONCLUSION: The improved synthetic procedure is shorter than the reported method by two steps and has advantages of simple separation, purification and conversion of configuration; easily available starting materials and reagents; concise operation. Two new bioactivities on reversing MDR and inducing apoptosis of luteal cell offered a clue in new drugs research and widened clinic application of droloxifene.
In order to find the effective components and new pharmaceutical effect of Alpinia officinarum, and further exploit it, we extracted its essential oils with the technique of Supercritical-CO2 fluid, then confirmed there were 27 components in Pot I And 111 components in Pot II by using the chemical component analysis and the computer information retrieval in the GC-MS system.
By using the extraction technique of supercritical-CO2 fluid on Amomum villodum Lour, essential oil could be got and then be applied to GC-MS online computer retrieval analysis, after a study on essential oil both in isolated pot I and II, 24 and 71 components were identified respectively.
By using the extraction technique of supercritical CO2 fluid on Amomum tsaoko Crevost et Lemaire, essential oil could be got and then be applied to GC-MS online computer retrieval analysis. After a study on essential oil both in isolated pot I and II, 65 and 93 components were identified respectively.
By using the extraction technique of supercritical CO2 fluid on Alpinia katsumada Hayata, essential oil could be got and then be applied to GC-MS online computer retrieval analysis. After a stuy on essential oil both in isolation pot I and II, 95 peaks and 126 peaks were recorded respectively, and 81 and 120 components were identified respectively.
Essential oil Components of Alpinia oxphylla were analyzed by way of applying gas chromatography, mass spetrography and computer interpretation; essential oil was abtained by supercritical CO2 fluid, thus we got 193 peaks in oil from Pot I and 210 peaks in oil from Pot II as well as identify 139 and 155 compounds respectively.
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PURPOSE: To compare and evaluate treatment plans for the fan-beam intensity modulated radiotherapy and the Gamma Knife radiosurgery for treating medium-size intracranial lesions (range 4-25 cm3). METHODS AND MATERIALS: Treatment plans were developed for the Leksell Gamma Knife and a fan-beam inverse treatment planning system for intensity modulated radiotherapy. Treatment plan comparisons were carried out using dose-volume histogram (DVH), tissue-volume ratio (TVR), and maximum dose to the prescription dose (MDPD) ratio. The study was carried out for both simulated targets and clinical targets with irregular shapes and at different locations. RESULTS: The MDPD ratio was significantly greater for the Gamma Knife plans than for the fan-beam IMRT plans. The Gamma Knife plans produced equivalent TVR values to the fan-beam IMRT plans. Based on the DVH comparison, the fan-beam IMRT delivered significantly more dose to the normal brain tissue than the Gamma Knife. The results of the comparison were found to be insensitive to the target locations. CONCLUSION: The Gamma Knife is better than the fan-beam IMRT in sparing normal brain tissue while producing equivalent tumor dose conformity for treating medium-size intracranial lesions. However, the target dose homogeneity is significantly better for the fan-beam IMRT than for the Gamma Knife.
Human umbilical vein endothelial cells (HUVEC), like most normal cells, are resistant to tumor necrosis factor-alpha (TNF)-induced apoptosis in spite of TNF activating sphingomyelinase and generating ceramide, a known inducer of apoptosis. Here we report that TNF activates another key enzyme, sphingosine kinase (SphK), in the sphingomyelin metabolic pathway resulting in production of sphingosine-1-phosphate (S1P) and that S1P is a potent antagonist of TNF-mediated apoptosis. The TNF-induced SphK activation is independent of sphingomyelinase and ceramidase activities, suggesting that TNF affects this enzyme directly other than through a mass effect on sphingomyelin degradation. In contrast to normal HUVEC, in a spontaneously transformed endothelial cell line (C11) TNF stimulation failed to activate SphK and induced apoptosis as characterized by morphological and biochemical criteria. Addition of exogenous S1P or increasing endogenous S1P by phorbol ester markedly protected C11 cell line from TNF-induced apoptosis. Conversely, N, N-dimethylsphingosine, an inhibitor of SphK, profoundly sensitized normal HUVEC to killing by TNF. Thus, we demonstrate that the activation of SphK by TNF is an important signaling for protection from the apoptotic effect of TNF in endothelial cells.
The ability of high density lipoproteins (HDL) to inhibit cytokine-induced adhesion molecule expression has been demonstrated in their protective function against the development of atherosclerosis and associated coronary heart disease. A key event in atherogenesis is endothelial activation induced by a variety of stimuli such as tumor necrosis factor-alpha (TNF), resulting in the expression of various adhesion proteins. We have recently reported that sphingosine 1-phosphate, generated by sphingosine kinase activation, is a key molecule in mediating TNF-induced adhesion protein expression. We now show that HDL profoundly inhibit TNF-stimulated sphingosine kinase activity in endothelial cells resulting in a decrease in sphingosine 1-phosphate production and adhesion protein expression. HDL also reduced TNF-mediated activation of extracellular signal-regulated kinases and NF-kappaB signaling cascades. Furthermore, HDL enhanced the cellular levels of ceramide which in turn inhibits endothelial activation. Thus, the regulation of sphingolipid signaling in endothelial cells by HDL provides a novel insight into the mechanism of protection against atherosclerosis.
Several substituted 8,8-dimethyl-2H,8H-pyrano[6,5-h]quinoline-2-ones and related compounds were synthesized and evaluated for their in vitro cytotoxicity against a panel of human tumor cell lines. The most active compound (3) showed significant cytotoxic activity with GI50 values in the micromolar range.
3,4-Dihydroxyphenylglycolaldehyde (DOPEGAL) is the neurotoxic monoamine oxidase A (MAO-A) metabolite of norepinephrine (NE). NE neurons in the locus ceruleus (LC) die in Alzheimer's disease (AD). To determine if DOPEGAL could contribute to NE neuron death in AD we measured levels of DOPEGAL, NE and their synthesizing enzymes in LC from AD and matched controls. We found 2.8- and 3.6-fold increases in DOPEGAL and MAO-A in AD LC neuronal cell bodies compared to controls. NE and dopamine beta-hydroxylase were increased by 3.8- and 10.7-fold, respectively. Implications for the mechanism of neuron death in AD are discussed.
In our search for novel anti-HIV agents, seven 17-carboxylated steroid derivatives were synthesized and evaluated as potential anti-HIV agents. Compound 13 exhibited potent anti-HIV activity in acutely infected H9 lymphocytes with EC50 and therapeutic index values of 0.8 microM and 300, respectively.