Preliminary study on immunotoxin for the prevention of Schistosomiasis japonica.
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Animals↗
Biomedical subjects
X Guan
Publications and source records attributed to X Guan.
Effect of batroxobin on expression of neural cell adhesion molecule in temporal infarction rats and spatial learning and memory disorder.
The effect of Batroxobin expression of neural cell adhesion molecule (NCAM) in left temporal ischemic rats with spatial memory disorder was investigated by means of Morri's water maze and immunohistochemical methods. The results showed that the mean reaction time and distance of temporal ischemic rats for searching a goal were significantly longer than those of sham-operated rats and at the same time NCAM expression of left temporal ischemic region was significantly increased. However, the mean reaction time and distance of Batroxobin-treated rats were shorter and they used normal strategies more often and earlier than those of ischemic rats. The number of NCAM immune reactive cells of Batroxobin-treated rats was more than that of ischemic group. In conclusion, Batroxobin can improve spatial memory disorder of temporal ischemic rats and the regulation of the expression of NCAM is probably related to the neuroprotective mechanism.
Animals↗
Chlorocatechol detection based on a clc operon/reporter gene system.
A sensitive and selective sensing system for chlorocatechols (3-chlorocatechol and 4-chlorocatechol) was developed based on Pseudomonas putida bacteria harboring the plasmid pSMM50R-B'. In this plasmid, the regulatory protein of the clc operon, ClcR, controls the expression of the reporter enzyme beta-galactosidase. When bacteria containing components of the clc operon are grown in the presence of chlorocatechols, ClcR activates the clcA promoter, which is located upstream from the beta-galactosidase gene. Thus, the concentration of chlorocatechols can be related to the production of beta-galactosidase in the bacteria. The concentration of beta-galactosidase expressed in the bacteria was determined by measuring the chemiluminescence signal emitted with the use of a 1,2-dioxetane substrate. ClcR has a high specificity for chlorocatechols and provides the sensing system with high selectivity. This was demonstrated by evaluating several structurally related organic compounds as potential interfering agents. Both 3-chlorocatechol and 4-chlorocatechol can be detected with this sensing system at concentrations as low as 8 x 10(-10) and 2 x 10(-9) M, respectively, using a 2-h induction period. In the case of 3-chlorocatechol, a highly selective sensing system was developed that can detect this species at concentrations as low as 6 x 10(-8) M after a 5-min induction period; the presence of 4-chlorocatechol at concentrations as high as 2 x 10(-4) M did not interfere with this system.
Arabidopsis Proteins↗
Estrogen-induced activation of the mitogen-activated protein kinase cascade in the cerebral cortex of estrogen receptor-alpha knock-out mice.
We have shown previously in the developing cerebral cortex that estrogen elicits the rapid and sustained activation of multiple signaling proteins within the mitogen-activated protein (MAP) kinase cascade, including B-Raf and extracellular signal-regulated kinase (ERK). Using estrogen receptor (ER)-alpha gene-disrupted (ERKO) mice, we addressed the role of ER-alpha in mediating this action of estrogen in the brain. 17beta-Estradiol increased B-Raf activity and MEK (MAP kinase/ERK kinase)-dependent ERK phosphorylation in cerebral cortical explants derived from both ERKO and their wild-type littermates. The ERK response was stronger in ERKO-derived cultures but, unlike that of wild-type cultures, was not blocked by the estrogen receptor antagonist ICI 182,780. Surprisingly, both the ER-alpha selective ligand 16alpha-iodo-17beta-estradiol and the ER-beta selective ligand genistein failed to elicit ERK phosphorylation, suggesting that a different mechanism or receptor may mediate estrogen-induced ERK phosphorylation in the cerebral cortex. Interestingly, the transcriptionally inactive stereoisomer 17alpha-estradiol did elicit a strong induction of ERK phosphorylation, which, together with the inability of the ER-alpha- and ER-beta-selective ligands to elicit ERK phosphorylation, and of ICI 182,780 to block the actions of estradiol in ERKO cultures, supports the hypothesis that a novel, estradiol-sensitive and ICI-insensitive estrogen receptor may mediate 17beta-estradiol-induced activation of ERK in the brain.
Animals↗
A study on producing monoclonal antibody with one diagnostic marker screened electrophoretically from the urine of individuals infected with Schistosoma japonicum.
One diagnostic marker (a glycoprotein with 30kDa) from the urine of individuals infected with S. japonicum was screened with electrophoresis, and used as antigen to produce McAbs. Two lines of McAbs, named NP56 and NP54,were obtained. McAb NP56 was of better immunoreactivity and its immunoglobulin isotype was IgG(2b.) McAb NP56 could react with SEA (soluble egg antigen) and AWA (adult worm antigen) and express on miracidia in eggs of S. japonicum. When determined with NP56 as a probe in indirect ELISA, the sensitivity and specificity of positive urine samples (EPG median 69) was 50% and 80% in original urine samples, and 90% and 100% in concentrated urine samples, respectively. The results above indicated that with established means it is feasible to produce McAb with the diagnostic marker screened electrophoretically from the metabolic product of the individuals infected with this pathogen, and that McAb-NP56 is of potential value in the diagnosis of chronic cases and individuals with light infection with S. japonicum.
Animals↗
Engraftment and growth of patient-derived retinoblastoma tumour in severe combined immunodeficiency mice.
The development of an in vivo model of retinoblastoma could be important for studying its biological behaviour and developing novel therapeutic strategies. We examined the ability of patient-derived retinoblastoma cells to grow and disseminate in severe combined immunodeficiency CB-17-SCID mice after subcutaneous (s.c.) inoculation without conditioning treatment. 24/30 (80%) of patient-derived tumours engrafted and grew as s.c. nodules in SCID mice. Whilst most xenografted tumours appeared to be localised, by PCR assay a positive DNA band of human minisatellite region (YNZ.22) was determined in the bone marrow of 19/25 (76%), in the spleen of 14/25 (56%) and in the liver of 16/25 (64%) mice, respectively, indicating dissemination to distant organs. Cytogenetic analysis demonstrated i(6p) in 5/12 (42%) and trisomy 1 or 1q abnormalities in 8/12 (67%) of the xenografted tumour samples studied, respectively, suggesting that retinoblastoma tumour cells maintain their cytogenetic abnormalities following adoptive growth in SCID mice. In this report we demonstrate the ability to propagate human primary retinoblastoma cells in SCID mice after s.c. inoculation and suggest the possibility of using the SCID mouse model to study the intrinsic biological behaviour of human retinoblastoma and to develop novel therapeutic strategies in the treatment of this disease.
Animals↗
High chromium yeast supplementation improves glucose tolerance in pigs by decreasing hepatic extraction of insulin.
Twenty Landrace x Yorkshire cross pigs (body wt, 47.9+/-2.9 kg) were used to evaluate effects of dietary high chromium (Cr) yeast supplementation on plasma kinetics of glucose, insulin and C-peptide. Pigs were provided free access to either a control diet (C) containing 204 microg Cr/kg or a diet supplemented with an additional 200 microg Cr/kg as high Cr yeast (CR) for between 23 and 30 d. After overnight food deprivation, dextrose (500 g/L) was infused through a jugular vein catheter at a dose of 0.5 g glucose/kg body weight with an infusion rate of 10 g glucose/min within 6 min. High Cr yeast supplementation did not affect body weight gain or food intake. There were no differences in fasting plasma concentrations of either glucose or C-peptide, although basal plasma concentration of insulin tended to be higher in pigs fed CR (P<0.10). Plasma glucose concentrations were lower (P<0.01) at postinfusion times 5, 10, 15 and 20 min in pigs fed CR. Plasma insulin concentrations in pigs fed CR were higher (P<0.05) at 2 and 0 min before the completion of dextrose infusion. However, the increase in plasma insulin concentrations was not accompanied by a comparable elevation in plasma C-peptide concentrations. The 30-min (postinfusion) area of plasma glucose concentrations tended to be lower (P<0.10) in pigs fed CR, but there were no differences in 30-min areas of either plasma insulin or plasma C-peptide concentrations between treatments. Plasma clearance rates of glucose, insulin and C-peptide were higher and their half-lives shorter (P<0.05) in pigs fed CR. In conclusion, dietary high Cr yeast supplementation improved glucose tolerance, possibly through a decrease in hepatic extraction of insulin.
Animals↗
[The application of fluorescence in situ hybridization performed on the decolorized G-banding chromosomes in detecting the marker chromosomes of gastric cancer].
OBJECTIVE: Using a rapid, accurate method that detects the marker chromosomes of gastric cancer and enhancing the ability of discriminating complicated chromosome rearrangements of gastric cancer. METHODS: The improved method of fluorescence in situ hybridization(FISH) performed on the decolorized G-banding chromosome was used. RESULTS: The changes of two marker chromosomes (M1, M2) of the cell line(SGC-7901) of gastric cancer and one marker chromosomes(M3) of one primary gastric cancer were respectively analyzed by this method. The M1, M2 and M3 had complicated structural chromosome aberrations: del(7)(p15)/del(7)(q22), t(1;3)(p11;q11) and del(7)(q32). CONCLUSION: This method showed strong signals, low backgrounds and well-repetitions. It may play an important part in exploring the chromosome rearrangements in the process of pathogenesis and development of gastric cancer.
Chromosome Aberrations↗
Anti-fecundity immunity in mice immunized with anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum.
OBJECTIVE: To observe the effects of anti-fecundity and anti-embryonation immunity of anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum on female adult worm. METHODS: The active immunization of C57BL/6 mice was conducted by means of three intraperitoneal injections of NP30. The control group was injected with SP2/0 ascites intraperitoneally. RESULTS: On the twenty-seventh day after challenge infection, the number of eggs in the liver tissue and in uterus of the group immunized with NP30 decreased by 30.91% and by 38.55%, respectively. On the thirty-ninth day after the challenge infection, the number of mature eggs in the liver tissue of the group immunized with NP30 decreased by 66.63% and the number of dead eggs increased by 60.66%. CONCLUSIONS: NP30, with which mice were actively immunized, possesses double effects of anti-fecundity and anti-embryonation immunity on female adult worm of Schistosoma japonicum, therefore it can be used as a promising candidate of anti-pathologic vaccine molecule against Schistosomiasis japonica.
Animals↗
[Clinical observation of taxotere in the treatment of advanced non-small-cell lung cancer and breast cancer].
OBJECTIVE: To observe the response rate and toxic reaction of taxotere in the treatment of advanced NSCLC and breast cancer. METHODS: A total of 24 cases was included in the study. Taxotere 75 mg/m2 i.v. drip for 1 hour; dexamethasone 8 mg bid 24 hour before taxotere, and continued for 3 days. For NSCLC, the taxotere was combined with DDP 90 mg/m2; for breast cancer, it was combined with ADM 40 mg/m2. The second treatment cycle was given after 3 weeks. At last 2 cycles were given. RESULTS: In 15 NSCLC patients, there were 6 PR, 7 NC and 2 PD. In 9 breast cancer patients, there were 2 CR, 6 PR and 1 NC. The major toxic reactions were neutropenia, diarrhea, fatigue, muscle pain and alopecia. Grade 3 and grade 4 neutropenia occurred in 9 and 4 cases, respectively. Decrease in hemoglobin and thrombocytopenia were mild. Diarrhea occurred in 19 cases and allergic reaction in 1 case. CONCLUSION: Taxotere is effective in the combined treatment of advanced NSCLC and breast cancer. The toxic reactions are tolerable.
Adult↗
[Induction of apoptosis in various cancer cell lines by human soluble TRAIL expressed in Escherichia coli].
OBJECTIVE: To investigate the induction of apoptosis by human soluble TRAIL expressed in Escherichia coli and analyze its relationship with p53 in various cancer cell lines, especially the solid tumor. METHODS: TRAIL codons 114 approximately 281 were amplified by polymerase chain reaction. The soluble segment was expressed in Escherichia coli JF1125, refolded and purified. Induction of apoptosis was assessed by examination of morphological changes under electron microscope and quantified by FACS analysis. The mutation of p53 in employed cell lines was detected by immunohistochemistry. RESULTS: By multi-step purification, the purity of human soluble TRAIL exceeded 90%. Induction of apoptosis by the product exhibited a marked increase in human breast cancer cell line MCF-7, HeLa cervical carcinoma cells and hepatocellular carcinoma cell lines SMMC7721, BEL7402, and BEL7405. The mutation of p53 in employed cell lines was positive in aforementioned cell lines. CONCLUSION: The human soluble TRAIL expressed in Escherichia coli has similar activity to that generated in cells to induce apoptosis in various cancer cell lines, and acts independently of p53.
Apoptosis↗
[Relationship of bcl-2 gene expression with cell proliferation and apoptosis in human gliomas].
OBJECTIVE: To investigate the relationship of bcl-2 gene expression level in human gliomas with the malignant degree, cell proliferative activity and apoptosis of the tumors. METHODS: The expression of bcl-2 mRNA, bcl-2 protein and proliferating cell antigen, and the apoptosis in sixty-nine human glioma specimens with different malignant grades were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry. RESULTS: Of the 69 gliomas, 64 (92.8%) and 60 (87.0%) expressed bcl-2 mRNA and bcl-2 protein, respectively. The expression levels of bcl-2 mRNA and bcl-2 protein were correlated positively with each other (r(s) = 0.999, P < 0.01). The expression levels of bcl-2 mRNA and bcl-2 protein were both higher in WHO grade IV gliomas than in grade III gliomas, and the expression was lowest in grade I-II gliomas (P < 0.02 approximately 0.001). With the increase in the expression of bcl-2 protein, the cell proliferating activity increased and apoptosis decreased in the tumor cells. There was significant difference of cell proliferation and apoptosis between + + + group and + + group of bcl-2 protein expression (P < 0.05) as well as between both the former groups, and the negative and + group (P < 0.01) respectively. CONCLUSIONS: Over-expression of bcl-2 gene inhibits apoptosis of glioma cells, and the inhibitory intensity increases with the ascending of bcl-2 gene expression level in glioma cells. Both the decrease in apoptosis caused by bcl-2 gene over-expression and the excessive cell proliferation promoted by other gene abnormalities may result in unlimited cell accumulation, which may play an important role in the development and malignant progression of gliomas.
Adolescent↗
[The devitalization of tumor suppressor genes in oral squamous cell carcinoma].
OBJECTIVE: To study the expression of anti-oncogenes nm23, P16, P53 of squamous cell carcinoma within one sample. METHODS: A total of 27 cases of oral squamous cell carcinoma came from our the First Clinical College, China Medical University from 1997 to 1998, and none of them had the history of radioactivity therapy or chemical therapy. In them, 8 cases were in the early period, and 19 cases were in the late period. 15 cases were male and 12 cases were female. The samples were fixed in formaldehyde solution, embedded with paraffin, sliced in 5 microns, and analysed by ABC immunohistochemistry staining. The first antibodies were anti-P16, anti-nm23, anti-P53 respectively. The criteria of judgment were the following: For nm23, the case that cytoplasm or nucleus were buffy particles or ball was positive. For P16, the case that nucleus were brown was positive, while the case with the light brown cytoplasm and unstained nucleus was negative. The stained nucleus of interstitial cells were treated as the control. For p53, the positive protein product was assembled in the carcinoma cell nucleus, so the nucleus with buffy or brown particles was positive. According to the criteria, 5 high power sights were selected from each case, more than one hundred cells were counted. The case that the positive cells was more than 30 percentage was high expression, and less than 30 percentage was low expression. Two doctors completed the procedure respectively, and only the same results could be qualified. RESULTS: In the 27 cases, the devitalization of nm23 and p16 was showed in low expression, p53 in high expression. The devitalization rate: p16 was 66.7%, nm23 was 48.1%, and p53 was 25.9%. In 14 cases, combined mutation of two inhibitory genes were seen. 9 cases were p16 and nm23, among them, 4 cases had transferred to cervical lymph nodes (In all the cases, there were 6 cases who had cervical lymph node transference). CONCLUSION: p16 genetic changes are more often detected in oral squamous cell carcinoma than the other genetic changes; In a large portion of cases, there were combined genetic changes instead of single gene mutation.
Adult↗
[Interaction between biofilm formed by Pseudomonas aeruginosa and antibacterial agents].
UNLABELLED: We hypothesized that bacterial biofilm formation could be an important factor that make some infection intractable. Interaction of P. aeruginosa biofilm with antibactial agents was examined in vitro. METHODS: P. aeruginosa incubated for 6 days in a saline-teflon system formed biofilm on the surfaces of the teflon piece. The biofilm were characteried by dense colonization of bacteria and thick membranous structure that covered the colonies, it was observed with a scanning electron microscopy. CPFX, CAM, ROX and Herba Andrographitis were added to the biofilm bacteria. RESULTS: The rate of survial of the floating bacteria decreased to 0.02% after 4 hours of contact with 2MIC of Ciprofloxacin (CPFX), but that of biofilms was 41% When 10 micrograms/mL of Clarithromycin (CAM per mL was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.2%. When 12 micrograms/mL of Roxithromycin (ROX) was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.5%. When 0.05 g of Burm. f. per mL was combined with CPFX the survial rate for the biofilm bacteria decreased to 2.7%. CONCLUSION: We conclude that biofilm bacteria are much more resistant to CPFX than the floating bacteria. The combination of CPFX and CAM, ROX HA were more effective in decreasing the biofilm bacteria survial rate than CPFX alone. The results suggest that the combination of CPFX and CAM, ROX, HA can be one of the therapeutic manauvers against biofilm bacteria.
Anti-Bacterial Agents↗
Restricting the mobility of Gs alpha: impact on receptor and effector coupling.
The alpha-subunit of the stimulatory G protein, Gs, has been shown to dissociate from the plasma membrane into the cytosol following activation by G protein-coupled receptors (GPCR) in some experimental systems. This dissociation may involve depalmitoylation of an amino-terminal cysteine residue. However, the functional significance of this dissociation is not known. To investigate the functional consequence of Gs alpha dissociation, we constructed a membrane-tethered Gs alpha (tetGs alpha), expressed it in Sf9 insect cells, and examined its ability to couple with the beta(2) adrenoceptor and to activate adenylyl cyclase. Compared to wild-type Gs alpha, tetGs alpha coupled much more efficiently to the beta 2 adrenoceptor and the D1 dopamine receptor as determined by agonist-stimulated GTP gamma S binding and GTPase activity. The high coupling efficiency was abolished when Gs )alpha was proteolytically cleaved from the membrane tether. The membrane tether did not prevent the coupling of tetGS alpha to adenylyl cyclase. These results demonstrate that regulating the mobility of Gs alpha relative to the plasma membrane, through fatty acylation or perhaps interactions with cytoskeletal proteins, could have a significant impact on receptor-G protein coupling. Furthermore, by enabling the use of more direct measures of receptor-G protein coupling (GTPase activity, GTP gamma S binding), tetGS alpha can facilitate the study for receptor-G protein interactions.
Adenylyl Cyclases↗
Arachidonic acid amide inhibitors of gap junction cell-cell communication.
A series of arachidonic acid amides including anandamide and arachidonamide that act as potent inhibitors of the rat glial cell gap junction is described.
Animals↗
Estrogen-induced activation of mitogen-activated protein kinase in cerebral cortical explants: convergence of estrogen and neurotrophin signaling pathways.
We have shown that estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing CNS. We subsequently demonstrated widespread colocalization of estrogen and neurotrophin receptors (trk) within developing forebrain neurons and reciprocal transcriptional regulation of these receptors by their ligands. Using organotypic explants of the cerebral cortex, we tested the hypothesis that estrogen/neurotrophin receptor coexpression also may result in convergence or cross-coupling of their signaling pathways. Estradiol elicited rapid (within 5-15 min) tyrosine phosphorylation/activation of the mitogen-activated protein (MAP) kinases, ERK1 and ERK2, that persisted for at least 2 hr. This extracellular signal-regulated protein kinase (ERK) activation was inhibited successfully by the MEK1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780, and did not appear to result from estradiol-induced activation of trk. Furthermore, we also found that estradiol elicited an increase in B-Raf kinase activity. The latter and subsequent downstream events leading to ERK activation may be a consequence of our documentation of a multimeric complex consisting of, at least, the ER, hsp90, and B-Raf. These novel findings provide an alternative mechanism for some of the estrogen actions in the developing CNS and could explain not only some of the very rapid effects of estrogen but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation.
Animals↗
Geranoyl-CoA carboxylase: a novel biotin-containing enzyme in plants.
Geranoyl-CoA carboxylase (EC 6.4.1.4) is a biotin-containing enzyme previously described in two genera of bacteria. Here we report the presence of geranoyl-CoA carboxylase in kingdom Plantae. Geranoyl-CoA carboxylase was purified 180-fold from maize leaves. The enzyme has a biotin-containing subunit of 122 kDa. The pH optimum for activity is 8.3. The apparent Km values for the substrates geranoyl-CoA, bicarbonate, and ATP are 64 +/- 5 microM, 0. 58 +/- 0.04 mM, and 8.4 +/- 0.4 microM, respectively. Subcellular fractionations indicate that geranoyl-CoA carboxylase is located in plastids. Geranoyl-CoA carboxylase activity is ubiquitous in organs of monocots and dicots and varies with development. We postulate that geranoyl-CoA carboxylase plays an important role in isoprenoid catabolism in plants, in a pathway analogous to that shown in Psuedomonas sp. In plants, this catabolic pathway would require the interaction of at least three subcellular compartments (plastids, microbodies, and mitochondria) and two biotin-containing enzymes, geranoyl-CoA carboxylase and 3-methylcrotonyl-CoA carboxylase.
Biotin↗