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Biomedical subjects

L Xue

Publications and source records attributed to L Xue.

At least 73 records · Page 4Linked to original sources

[Ultrastructural changes after space flight in Platycodon grandiflorum (Jacq.) DC].

OBJECTIVE: To substantiate the effect of space conditions on medicinal plants. METHOD: The seeds of platycodon grandiflorumg were set up in retrievable satellites. After returning to earth, the ultrastructural changes of leaves were studied. RESULT: Under light microscope, the leaf tissue structure of the flight group and the earth controlled group were alike and under electron microscope, some differences could be found in the nucleus and choloroplasts between the two groups. CONCLUSION: Space environment has some effect on Platycodon grandiflorum, and the effect needs to be further explored.

Cell Nucleus↗

[Studies on the effects of space flight on Carthamus tinctorius L].

OBJECTIVE: To substantiate the effects of space condition of medicinal plants. METHODS: The seeds of Carthamus tinctorius were sent to space in retrievable satellites. After returning to earth, the seeds were stored at 0-4 degrees C, and cultured in the test field in the spring of next year. The peroxidases, soluble proteins and ultrastructure of leaves were studied in flowering stage. RESULTS: The peroxidase activity of the flight group was lower than that of the earth controlled group, and the protein content of the flight group was higher than that of the earth controlled group. The main bands in electrophoresis patterns of peroxidases and proteins were alike, and some bands were different. Some changes could be observed in the ultrastructure of chloroplast between the flight group and the earth controlled group. CONCLUSION: Space environments have some effect on Carthamus tinctorius. The results of this experiment are consistent with those of the previous experiment.

Carthamus tinctorius↗

[Effect of space flight on ultrastructure in medicinal plant Datura innoxia Mill].

OBJECTIVE: To substantiate the effect of space environment on medicinal plants. METHOD: The seeds of Datura innoxia were set up in retrievable satellites. After returning to earth, the ultrastructural changes were observed by means of electron microscope. RESULTS: In cells of weightless group and hit group, some changes were found in chloroplast grana, starch grains and vesicles in chloroplasts. No obvious changes were observed in nuclei. CONCLUSION: Space environment has some effect on the ultrastructure in D. innoxia, and chloroplast is more sensitive to space environment than other organs.

Chloroplasts↗

[Analysis of the relationship between the facial skin temperature and blood flow].

The relationship between the blood flow of temperal or facial artery and facial skin temperature was studied in 30 patients with facial nerve paralysis. The facial skin temperature was recorded by infrared thermography, and the blood flow was measured by ultrasonic Doppler flowetry. The results showed, in the same facial region, the greater the volume of blood flow was, the higher the skin temperature stood. After acupuncture on the facial points, the facial blood flow increased and the facial skin temperature rose. The ratios between the increase in facial skin temperature and the in increase in blood flow were 0.9538-1.2835(degrees:ml/second) in four facial regions. These indicate the presence of certain quantitative relationship between the facial blood flow and the skin temperature.

Adult↗

[Efficient, stable expression of human interleukin-15 cDNA in Chinese hamster oval cells].

OBJECTIVE: To express the human interleukin 15(IL-15) cDNA in Chinese hamster oval (CHO) cells, which would benefit to the further research in the biological activities and the clinical applications of IL-15. METHODS: The entire human interleukin-15(IL-15) coding region, deleted of all the uncoding fragments, was amplified by PCR. The amplified products were subcloned into the EcoR I and Xba I sites of the pcDNA3 plasmid, forming the recombinant eukaryotic expressing vector, pcDNA3-IL-15, which was then identified by the Bg1 II enzymatic digestion, PCR amplification and the sequence analysis. The construct was transfected into CHO cells by means of lipofectamine, followed by a series of determinations to screen the positive cell colonies, such as RT-PCR, SDS-PAGE, ELISA and CTLL-2 proliferation assay. RESULTS: 8 positive cell colonies highly expressed human IL-15 were obtained after G418 selection. The bioassay showed that the mean activities of the supernatants from the CHO-IL-15 cells were (318.54 +/- 32.76) U/(10(6) cells.d) and maintained stable after 6 months culture. CONCLUSIONS: Human IL-15 cDNA was expressed efficiently and persistently in CHO cells.

Animals↗

[Effect of space flight on ultrastructure of chloroplast in Agastache rugosa].

OBJECTIVE: To substantiate the effects of space condition on medicinal plants, the seeds of Agastache rugosa were set up in retrievable satellites. METHODS: After returning to earth, the ultrastructural changes of chloroplasts were examined by means of electron microscope. RESULTS: Vesicles could be seen in the chloroplasts in the cells of earth controlled group, it was few and could not be found in the chloroplasts in the cells of weightless group and hit group. Some chloroplasts were degrading in the cells of weightless group, but this phenomenon was not observed in the cells of the other two groups. CONCLUSIONS: These results showed that space environment had some effect on the ultrastructure of chloroplasts in Agastache rugosa.

Agastache↗

Alteration of the properties of gastric smooth muscle in the genetically hyperglycemic OLETF rat.

Membrane responses were recorded from isolated gastric smooth muscle of Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) rats, using microelectrode techniques. At the age of 68-76 weeks, the blood sugar level was 181 mg/dl in LETO rats and 350 mg/dL in OLETF rats. In both rats, the membrane potential was stable in fundus muscle and spontaneously active with generation of slow waves in antrum muscle. The resting membrane potential was about - 46 mV in fundus and - 55 mV in antrum muscles of LETO rats, and the values were 3-7 mV lower in OLETF rats. The slow waves were generated regularly in LETO rats, while they were irregular and of small amplitude in OLETF rats. Transmural nerve stimulation evoked a cholinergic excitatory junction potential and following inhibitory junction potential in LETO rats, and only an inhibitory junction potential of smaller size was generated in most of OLETF rats. The acetylcholine-induced depolarization was greater in OLETF than in LETO rats. The level of hyperpolarization produced by noradrenaline was similar between OLETF and LETO rats. Thus, the reduction of the resting membrane potential, weakening of spontaneous activity, impairment of cholinergic transmission and cholinergic supersensitivity were associated with hyperglycemia. These alterations were considered due to the development of diabetes mellitus.

Acetylcholine↗

ERK2 signalling from internalised epidermal growth factor receptor in broken A431 cells.

Activation of extracellular signal-regulated kinase 2 (ERK2) signalling from epidermal growth factor receptors (EGFRs) is widely assumed to originate in the plasma membrane. Using an in vitro assay, we investigated whether EGF/EGFR complexes internalised by endocytosis in A431 cells can initiate signalling in the ERK2 pathway. At 0 degrees C, binding of EGF induced tyrosine phosphorlyation of EGFR and, when the cells were subsequently broken by scraping and warmed in the presence of exogenous cytosol, activation of ERK2 occurred. At 0 degrees C, washes with pH 4.5 media reversed EGF binding, tyrosine phosphorylation and ERK-2 activation in exogenous cytosol, providing conditions in which signalling from the cell surface and internalised EGFRs could be distinguished. When cells containing internalised EGF/EGFR complexes were first washed in low pH media at 0 degrees C and then broken and incubated in exogenous cytosol, substantial activation of ERK2 occurred. This activation reached a maximum after a 5-min internalisation and was almost completely prevented by incubation in 0.45 M sucrose, a known inhibitor of receptor-mediated endocytosis. These data are consistent with activation of the ERK2 signalling pathway by internalised EGRFs situated in endosomal compartments. Our observation that EGFR tyrosine dephosphorylation is incomplete above pH 5.5 suggests that signalling is initiated in early endosomes.

Calcium-Calmodulin-Dependent Protein Kinases↗

A novel Na+/HCO3--codependent choline transporter in the syncytial epithelium of the cestode Hymenolepis diminuta.

Absorption of exogenous choline by the cestode Hymenolepis diminuta was found to be both Na+- and HCO3--dependent and, at pH 6 to 7, accounted for up to 65% of the total choline uptake. Na+/HCO3- dependent choline uptake was activated at approximately 6 mM HCO3- (EC50 approximately 9 mM), and, above 100 mM Na+, the rate of uptake was directly proportional to the Na+ concentration. Atempts to uncouple Na+-dependent uptake from HCO3--dependent uptake were not successful: K+-depolarization was without effect on HCO3--dependent choline uptake, and use of valinoomycin to hyperpolarize the brush-border membrane resulted in inhibition of uptake. Na-/HCO3--dependent choline uptake was not associated with solvent drag. The Na+/HCO3--dependent choline uptake displayed a Q10 of 6.4 (27 degrees to 37 degrees) and a relatively high activation energy of 126 kJ x mol(-1). At pH 6.0 and 7.0, Na-/HCO3--dependent choline uptake rates were similar, but Na+/HCO3--dependent choline uptake was reduced at pH 5.0. The Na+/HCO3--dependent choline uptake, at pH 7.0, displayed a Kt of approximately 500 microM and a Vmax of 4.01 pmol x mg wet weight(-1) x min(-1). The Na+/HCO3--dependent choline uptake was hemicholinium-3 sensitive, but not significantly inhibited by 200 microM bumetanide, 100 microM amiloride, benzamil, or EIPA or by 1 mM 4,4'-diisothiocyano-2,2'-stilbene disulfonate (DIDS) or 4-acetamido-4'-isothiocvanostilbene-2,2'-disulfonic acid (SITS). Although it remains to be shown that HCO3- uptake is coupled directly to both choline and Na+ uptake, the data suggest that choline up take occurs via choline/Na+/HCO3--co-trans porter.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

The spatial and temporal concentrations of choline in the lumen contents of the small intestine of uninfected and Hymenolepis diminuta infected rats.

The spatial and temporal concentrations of free choline in the lumen of the small intestine of the uninfected and Hymenolepis diminuta-infected rat were investigated. In the unfed infected or uninfected rat, the choline concentrations ranged from approximately 500 microM in the duodenum to approximately 20 microM in the posterior ileum, with some segments in infected rats containing significantly higher choline levels than in uninfected rats. Following feeding, choline levels were significantly elevated to approximately 3 mM by 6 h, although these concentrations fell rapidly in transit down the intestine. By 12 h the choline levels were similar to those in the unfed rat. An initial small shift in the worm biomass toward the duodenum after feeding was followed by a redistribution of biomass along the length of the small intestine. The worm biomass, however, had little or no effect on the choline levels. The high concentrations of free choline observed in the anterior regions of the intestine are postulated to be predominantly determined by nutritional intake while the concentrations in the posterior region may in part be determined by blood choline levels. The high levels of choline indicate that choline is not limiting to support the growth of the worms.

Animals↗

Effects of suramin on electrical and mechanical activities in antrum smooth muscle of the guinea-pig stomach.

The effects of suramin on electrical and mechanical responses produced by adenosine triphosphate (ATP), acetylcholine and transmural nerve stimulation were observed in antrum smooth muscle isolated from the guinea-pig stomach. Suramin (>10(-6) M) inhibited the non-adrenergic non-cholinergic inhibitory junction potential, with no alteration of the resting membrane potential, slow wave and the ATP-induced responses (hyperpolarization and inhibition of slow waves). The amplitude, but not the frequency, of spontaneous rhythmic contraction was inhibited by suramin (>10(-5) M), with no alteration of electrical responses of the membrane. Transmural nerve stimulation elicited cholinergic excitatory and non-adrenergic non-cholinergic inhibitory responses on the spontaneous contraction, and suramin inhibited only the latter. Suramin did not alter the ATP-induced inhibition of spontaneous contraction. The contractions produced by low concentrations (<10(-7) M), but not high concentrations (10(-6) - 10(-5) M), of acetylcholine were inhibited by suramin. It is concluded that in smooth muscle of the guinea-pig antrum, suramin inhibits contractions produced spontaneously and by low concentrations of acetylcholine, with no relation to the electrical responses of the membrane. Parallel inhibition by suramin of the electrical and mechanical responses elicited by excitation of non-adrenergic non-cholinergic inhibitory nerves may not be causally related to the inhibition of ATP-receptors.

Acetylcholine↗

Homologous recombination and DNA-end joining reactions in zygotes and early embryos of zebrafish (Danio rerio) and Drosophila melanogaster.

A linear DNA with partial sequence redundancy can be recircularized in cells by either nonhomologous end joining (NEJ) or by homologous recombination (HR). We have studied the relative contributions of these processes in zygotes or early embryos of species that serve as model organisms for developmental genetics. Thus, we have microinjected a linearized plasmid substrate into zygotes of zebrafish (Danio rerio) or into the posterior end of Drosophila melanogaster early embryos before pole cell formation. Similar to the situation observed previously in Xenopus zygotes/early embryos, we detected a large preponderance of DNA-end joining over homologous recombination. A comparison of end-joined junctions revealed that from the three species tested, zebrafish introduced the least number of sequence distortions upon DNA-end joining, while Drosophila produced the largest deletions (average 14 bp) with occasional nucleotide patch insertions, reminiscent of the N nucleotides at V(D)J junctions in mammalian immune receptor genes. Double-strand gap repair by homologous sequences ('homologous recombination') involving a bimolecular reaction was readily detectable in both zebrafish and Drosophila. This involved specifically designed recombination substrates consisting of a mutagenized linear plasmid and DNA fragments carrying the wild-type sequence. Our results show that the basic machinery for homologous recombination is present at early developmental stages of these two genetic model organisms. However, it seems that for any experimental exploitation, such as targeted gene disruption, one would have to inhibit or bypass the overwhelming DNA-end joining activity.

Animals↗

[Adaptive response of CHL to hydrogen peroxide induced oxidative stress and the mechanism].

OBJECTIVE: To study peroxidative adaptive response of eukaryocyte and its mechanisms. METHODS: Chinese hamster fibroblast cells (CHL) pretreated with low concentration of hydrogenperoxide (H2O2) were retreated by the following high concentration of H2O2. Cellular viability (MTT method) and DNA strand break (FADU method), as adaptive-acting indicators were selected. Meanwhile, CAT activity and PARP were separately determined on the adaptive response to DNA strand break. RESULTS: There were peroxidative adaptive responses to non-lethal damage of high concentration H2O2 in both cellular viability and DNA strand break levels; but adaptive models (conditions) between the two levels were different. The CAT activity induced by the low level of H2O2 was enhanced and related to peroxidative adaptation to DNA break. Furthermore, PARP blocker, 3-AB, markedly inhibited the adaptive response to DNA-strand break. CONCLUSION: Two models adaptation may be via different inducible adaptive pathways. CAT and PARP participated in the induction of peroxidative adaptation to DNA strand break.

Adaptation, Physiological↗

Study on delay two-phase multiple organ dysfunction syndrome.

OBJECTIVE: To study the injury factors, pathogenic process and clinical features of delay two-phase multiple organ dysfunction syndrome (MODS) in severe burned patients and to replicate a standardized animal model that would accurately imitate the clinical features of MODS. METHODS: Forty-five human patients with burn size larger than 30% total body surface area (TBSA) were analyzed. All of them underwent severe burn shock in early stage and sepsis in late stage. Thirty-two goats were randomly divided into three groups: 1) hemorrhagic shock (group H, n = 6); 2) endotoxemia (group E, n = 6); and 3) hemorrhagic shock plus endotoxemia (group M, n = 20). Hemorrhagic shock was produced according to the method of Wigger (6.7 kPa for an hour, 1 kPa = 7.5 mmHg). Endotoxin (E. coli O111 B4) was given via the portal vein 24 hours after the resuscitation of hemorrhagic shock, in a dose of 30 ng/kg/min for 5 consecutive days. During the observation period of 10 days, all animals were hemodynamically monitored, given standard metabolic support and due cardiac and pulmonary support according to human intensive care. RESULTS: All the patients showed burn shock at 1-3 days and hyperdynamic circulation, hypermetabolism and systemic inflammatory responses over two weeks post-injury. Thirteen cases were found to develop MODS according to the prevailing diagnostic criteria, and 10 of them died with a mortality of 77%. Eighteen animals died in group M with a mortality of 90%, 12 of the 18 developed MODS, with overall incidence of 60%. Most animals in group M showed changes similar to that observed in human cases. The experimentation proved that in the pathogenic process of MODS, there was a two-hit phenomenon in the dvelopment of the syndrome. To prevent the development of MODS, it therefore was imperative to blunt the first hit or the second hit, so that an excessive inflammatory response was alleviated. This postulation has been verified in the treatment of extensive burns. Two patients with burn extent reaching 100% TBSA survived with only mild acute respiratory distress syndrome (ARDS) and renal dysfunction after comprehensive treatment of burn shock, including adequate fluid resuscitation, drugs to remove oxygen free radicals, rapid restoration of pHi, and early extensive excision of burn eschars. CONCLUSION: Both in human patients or animal experimentation, the typical delay two-phase MODS is shown to be produced by two successive insults in the forms of hypovolemic shock and sepsis. This postulation is helpful in formulating the prevention and treatment modality of MODS.

Adult↗

[The characteristics and significance of oncogenes expression in oval cells cultivated in vitro].

OBJECTIVE: To study the relationship between expression characteristics of oncogenes and transformation of the oval cells cultivated in vitro. METHODS: Liver oval cells of SD rats induced by feeding with chemical carcinogen 3'-Me-DAB for four weeks were isolated using Percoll density gradient centrifugation. The cells were continuously cultivated in vitro and the dynamic characteristics of Ha-ras, Ki-ras and c-myc genes expression in the oval cells were detected using RNA-DNA slot blot hybridization. RESULTS: During long term cultivation, the population doubling time of the cells became shorter and the percentage of aneuploidy chromosomes and colonies grown in soft agar increased. Ha-ras Ki-ras and c-myc were synchronically expressed in the oval cells from different passages. CONCLUSION: The activation and synergistic over-expression of Ha-ras Ki-ras and c-myc had an important role in the proliferation and transformation of oval cells in vitro.

Animals↗

[Effect of space environment on germination and vegetation growth in Carthamus tinctorius L].

OBJECTIVE: To substantiate the effects of space condition on medicinal plants. METHOD: The seeds of medicinal plant Carthamus tinctorius were carried on board a retrievable satellite during 3-18 July, 1994. After returing to earth, the seedling rate, state of growth and development were observed. RESULT: The seeding rates, plant heights and branch quantities of weightless seeds and the seeds which were penetrated once and less than once by the heavy ion rays were higher than those of the seeds which were kept on earth, but these indexes of the seeds which were penetrated 2-3 times by the heavy ion rays were higher than those of the ground controlled seeds. CONCLUSION: Weightlessness and little penetration promote the growth and development of Carthamus tinctorius, but much penetration functions the other way round.

Carthamus tinctorius↗

[Gastroenteric absorptive kinetic study on strychine in Jiufensan].

After P. O. Jiufensan, the rest curve of strychine in stomach and intestines of mice per kg was determined by TLC scanning. And the gastroenteric absorptive kinetic rule of strychine in rivo was studied, As a result, the strychine in stomach and intestine of mice accorded with pharmacokinetic model of one room. Also the main pharmacokinetic parameters of this preparation were examined.

Animals↗