[Effects of culture conditions in vitro on apoptosis of leukemic cells].
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Apoptosis↗
Biomedical subjects
D Jiang
Publications and source records attributed to D Jiang.
[A study of gene expression of PDGFBB and PDGFR as well as level of PDGFR activity in human glioma cells].
OBJECTIVE: To investigate the effect of PDGFBB autocrine loop on the development and progression of human gliomas. METHODS: 73 human glioma specimens of different stages were studied using in situ hybridization and immunohistochemical techniques. RESULTS: 62 (84.9%) of 73 cases expressed PDGFB mRNA. The positive rate and the amount of PDGFB mRNA increased correspondingly with the degree of malignancy. All of 73 gliomas expressed PDGFR alpha, PDGFR beta and phosphotyrosine protein (P-Tyr). The positive cell densities of PDGFR alpha, PDGFR beta and P-Tyr correlated positively with one another and increased with the malignancy as well as the expression level of PDGFB mRNA in the gliomas. However, there was no significant difference between positive cell densities of PDGFR alpha and PDGFR beta in any glioma group with different grading. CONCLUSIONS: PDGFBB autocrine loop existed generally in the glioma cells, the expression levels of PDGFBB and PDGFRs were well correlated with the tumor grading and the positive cell density of P-Tyr which could objectively reflect the activity of PDGFRs and the signal pathways. It's suggested that abnormally increased activity of PDGFBB autocrine loop might play an important role in the development and progression of gliomas.
Adolescent↗
[A study on the relationship among activity of PDGFBB autocrine loop, cell proliferation and apoptosis in human glioma cells].
OBJECTIVE: To investigate the relationship between activity of autocrine loop of platelet-derived growth factor BB (PDGFBB), cell proliferation and apoptosis in gliomas. METHODS: 73 human gliomas with different degrees of malignancy were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry. RESULTS: The activity of PDGFBB autocrine loop and cell proliferation in gliomas correlated positively with each other and increased with the degree of tumor malignancy. Apoptosis decreased with the increase of malignancy and correlated negatively with the activity of PDGFBB autocrine loop as well as proliferation in glioma cells. CONCLUSION: These results suggest that all the above parameters have referential value in the evaluation of biological behavior of gliomas. Abnormal increase of activity of PDGFBB autocrine loop in glioma cells may be an important factor which stimulates cell proliferation and inhibits cell apoptosis and plays an important role in the development and progression of gliomas.
Adolescent↗
[The role of nitric oxide and nitric oxide synthase in the pathogenesis of asthma].
OBJECTIVE: To investigate the role of nitric oxide (NO) and nitric oxide synthase (NOS) in the pathogenesis of asthma. METHOD: 52 guinea pigs were randomly divided into four groups of 13 each: (1) asthmatic group (Group A): Dunkin-Hartley guinea-pigs were injected celiacly with 1 ml of 10% ovalbumin (OA). After 14 days, the animals were inhaled with an aerosol of 1% OA for 40-60 seconds for 10 days every other day; (2) Corticosteroid prevention group (Group CT): As above, just before the animals were inhaled with an aerosol, 0.5 mg/kg dexamethasone were injected celiacly; (3) N-nitro-L arginine prevention group (Group L): As Group A, just before the animals were inhaled with an aerosol, 0.4 mg/kg LNNA were injected celiacly; (4) Controls (Group C): and nitrate (NO2.-/NO3.-) levels in plasma, nitrite bronchoalveolar lavage fluid (BALF) and lung tissues were examined. At the same time, inducible nitric oxide synthase (iNOS) and constitute nitric oxide synthase (cNOS) activity levels in the lung tissues were examined, and the changes of cNOS in the guinea pig asthma model lung tissues were observed using histochemical detection. RESULT: All groups had no significant alteration of NO2.-/NO3.- in the plasma (P > 0.05). Group A had increased amounts of NO2.-/NO3.- in the BALF and in the lung tissues compared with the other groups (BALF: Group A 10.2 +/- 1.3, Group CT 7.2 +/- 1.1, Group L 7.3 +/- 1.3, Group C 6.2 +/- 0.8 mumol/L respectively, all of P < 0.01; the lung tissues: Group A 0.89 +/- 0.07, Group CT 0.16 +/- 0.09, Group L 0.24 +/- 0.09, Group C 0.18 +/- 0.05 nmol/mg respectively, all of P < 0.01). Group A also showed increased amounts of iNOS levels in the lung tissues than the other groups (Group A 59 +/- 18, Group CT 10 +/- 5, Group L 12 +/- 7, Group C 10 +/- 5 pmol/mg respectively, all of P < 0.01). Group L showed decreased amounts of cNOS levels in the lung tissues than the Group C (0.8 +/- 0.4, 1.2 +/- 0.4 fmol/mg, P < 0.05). While there were no significant alterations in the other groups (P > 0.05). Elevation of iNOS in the lung tissues was correlated with NO2-/NO3- in the BALF and in the lung tissues (r = 0.714, 0.842, respectively, P < 0.05, 0.01 respectively). NADPHd was found to be a histochemical marker reflecting cNOS activity. It was found that there was no marked alteration of cNOS activity in the Group A, Group CT and Group C, but lower in the Group L. CONCLUSION: There is increased production of iNOS in asthmatic guinea pigs, the iNOS produced could cause increased production of NO, and probably cause cytotoxicity and mediate airway hyperresponsiveness. NO and NOS may play an important role in the pathogenesis of asthma.
Animals↗
[Limbal epithelial autograft transplantation for treatment of pterygium].
OBJECTIVE: To observe the therapeutic effects of limbal epithelial autograft transplantation for treatment of pterygium. METHODS: Limbal epithelial autograft transplantation was performed on 68 cases (76 eyes) with pterygium or its recurrent lesion. The post-operative follow-up periods ranged from 6 to 18 months (mean, 9.8 months). RESULTS: Of 68 cases (76 eyes), there were 56 cases (62 eyes) with stable epithelial healing, recovery of corneal transparency and no abnormal proliferation of pterygium-like tissue, and 12 cases (14 eyes) loss of follow-up. CONCLUSION: To provide new stem cell source for injured limbus with limbal epithelial autograft transplantation is a reasonable therapeutic method for treatment of pterygium.
Adult↗
[Studies on trigonometric transform enhancement of chest radiograph based on its anatomical feature].
In this paper, we present a novel trigonometric transform contrast enhancement method for digital chest radiograph, which is based on the anatomical feature of the image processed. With automatic segmenting chest image into a lung region and a non-chest region, a positive linear transform and a negative one are used in lung region and the other region respectively. Therefore, it can enhance the contrast both in lung regions and in mediastinum region up to entire dynamic range of display device.
Algorithms↗
[Simulation study of selectively stimulating nerve fibers using biphasic pulses].
Biphasic selective stimulation is an effective electrical stimulation mode for preventing nerve fibers against electrochemical damage, for muscle to contract smoothly, and decreasing muscle's fatigue. By use of computer simulation, this paper presents three biphasic stimulation modes respectively using monopolr, bipolar and tripolar electrodes, which can effectively stimulate nerve fibers in a selective way. The results are helpful to the clinical application of neuroelectrical stimulation.
Computer Simulation↗
[An automatic method segmenting lung regions from digital chest radiograph].
It is difficult to process digital chest image with ordinary method because of the wide dynamic range of chest radiograph. Anatomically adaptive processing is a better method for chest image, but it needs automatic segmentation of the image. In this paper, an effective method for segmenting lung regions from digital chest radiograph is presented. This method automatically calculates the lung/mediastinum-subdiaphragmatic threshold according to the histogram of chest image processed.
Humans↗
[Assessment of diagnostic result for medical image by receiver operating characteristic and forced choice].
Two methods for diagnostic image evaluation, the receiver operating characteristic (ROC) and the forced choice, are introduced in this paper. The concepts of ROC and forced choice are described firstly, then the experiment design consideration and data analysis are discussed.
Choice Behavior↗
Characterization of Escherichia coli endonuclease VIII.
Escherichia coli endonuclease VIII (endo VIII) was identified as an enzyme that, like endonuclease III (endo III), removes radiolysis products of thymine including thymine glycol, dihydrothymine, beta-ureidoisobutyric acid, and urea from double-stranded plasmid or phage DNA and cleaves the DNA strand at abasic (AP) sites (Melamede, R. J., Hatahet, Z., Kow, Y. W., Ide., H., and Wallace, S. S. (1994) Biochemistry 33, 1255-1264). Using apparently homogeneous endo VIII protein, we now show that endo VIII removes from double-stranded oligodeoxyribonucleotides the stable oxidative products of cytosine, 5-hydroxycytosine and 5-hydroxyuracil. Endo VIII cleaved the damage-containing DNA strand by beta,delta-elimination as does formamidopyrimidine DNA glycosylase (Fpg). Like Fpg, endo VIII also excised the 5'-terminal deoxyribose phosphate from an endonuclease IV (endo IV) pre-incised AP site. Thus, in addition to amino acid sequence homology (Jiang, D., Hatahet, Z., Blaisdell, J., Melamede, R. J., and Wallace, S. S. (1997) J. Bacteriol. 179, 3773-3782), endo VIII shares a number of catalytic properties with Fpg. In addition, endo VIII specifically bound to oligodeoxynucleotides containing a reduced AP site with a stoichiometry of 1:1 for protein to DNA with an apparent equilibrium dissociation constant of 3.9 nM. Like Fpg and endo III, the DNase I footprint was small with contact sites primarily on the damage-containing strand; unlike Fpg and endo III, the DNA binding of endo VIII to DNA was asymmetric, 3' to the reduced AP site.
DNA↗
Detectability index measures of binaural masking level difference across populations of inferior colliculus neurons.
In everyday life we continually need to detect signals against a background of interfering noise (the "cocktail party effect"): a task that is much easier to accomplish using two ears. The binaural masking level difference (BMLD) measures the ability of listeners to use a difference in binaural attributes to segregate sound sources and thus improve their discriminability against interfering noises. By computing the detectability of tones from rate-versus-level functions in the presence of a suprathreshold noise, we previously demonstrated that individual low-frequency delay-sensitive neurons in the inferior colliculus are able to show BMLDs. Here we consider the responses of a population of such neurons when the noise level is held constant (as conventionally in psychophysical paradigms). We have sampled the responses of 121 units in the inferior colliculi of five guinea pigs to identical noise and 500 Hz tones at both ears (NoSo) and to identical noise but with the 500 Hz tone at one ear inverted (NoSpi). The result suggests that the neurons subserving detection of So tones in No (identical noise at the two ears) noise are those neurons with best frequencies (BFs) close to 500 Hz that respond to So tones with an increase in their discharge rate from that attributable to the noise. The detection of the inverted (Spi) signal is also attributable to neurons with BFs close to 500 Hz. However, among these neurons, the presence of the Spi tone was indicated by an increased discharge rate in some neurons and by a decreased discharge rate in others.
Animals↗
Innate control of the early course of infection in mice inoculated with Trypanosoma musculi.
Infections of mice with Trypanosoma musculi result in marked suppression of acquired humoral immunity but rapid activation of splenic NK cell cytotoxicity. We show that both NK cells and activated peritoneal space (PS) macrophages (MP) participate in the innate immune control of T. musculi infections preceding escape of curative antibody production from suppression. Splenic NK cytotoxicity reaches a peak on Days 3-4 of infection and then rapidly declines. Rising cytotoxicity is paralleled by a rising number of NK cells. The decline in cytotoxicity occurs even though the number of splenic NK cells continues to rise. The critical role of NK cells in the control of the early course of T. musculi infection was demonstrated by the effects of either depleting NK cells (antiasialo GM1 treatment) or maintaining them in an activated state (poly(I:C) injections). The importance of MP in controlling the infection was suggested by studies involving proteose peptone elicited MP both in vivo and in culture. The results presented here strongly suggest that innate immunity involving NK cells and MP can control, but not cure, T. musculi infections. Whether this early innate response influences the subsequent acquired, curative response remains to be studied. Detailed analyses of innate immunity in this experimental infection should suggest new approaches to intervention in early pathogenic infections.
Animals↗
Elevated expression of glutathione peroxidase in PC12 cells results in protection against methamphetamine but not MPTP toxicity.
In vivo administration of either 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or methamphetamine (MA) produces damage to the dopaminergic nervous system which may be due in part to the generation of reactive oxygen species (ROS). The resistance of superoxide dismutase (SOD) over-expressing transgenic mice to the effects of both MPTP and MA suggests the involvement of superoxide in the resulting neurotoxicity of both compounds. Superoxide can be converted by SOD to hydrogen peroxide, which itself can cause cellular degeneration by reacting with free iron to produce highly reactive hydroxyl radicals resulting in damage to proteins, nucleic acids and membrane phospholipids. Hydrogen peroxide has also been reported to be produced via inhibition of NADH dehydrogenase by MPP + formed during oxidation of MPTP by MAO-B and by dopamine auto-oxidation following MA-induced dopamine release from synaptic vesicles within nerve terminals. To test whether hydrogen peroxide is an important factor in the toxicity of either of these two neurotoxins, we created clonal PC12 lines expressing elevated levels of the hydrogen peroxide-reducing enzyme glutathione peroxidase (GSHPx). Elevation of GSHPx levels in PC12 was found to diminish the rise in ROS levels and lipid peroxidation resulting from MA but not MPTP treatment. Elevated levels of GSHPx also appeared to prevent decreases in transport-mediated dopamine uptake produced via MA administration as well as to attenuate toxin-induced cell loss as measured by either MTT reduction or LDH release. Our data, therefore, suggest that hydrogen peroxide production likely contributes to MA toxicity in dopaminergic neurons.
Animals↗
Escherichia coli endonuclease VIII: cloning, sequencing, and overexpression of the nei structural gene and characterization of nei and nei nth mutants.
Escherichia coli possesses two DNA glycosylase/apurinic lyase activities with overlapping substrate specificities, endonuclease III and endonuclease VIII, that recognize and remove oxidized pyrimidines from DNA. Endonuclease III is encoded by the nth gene. Endonuclease VIII has now been purified to apparent homogeneity, and the gene, nei, has been cloned by using reverse genetics. The gene nei is located at 16 min on the E. coli chromosome and encodes a 263-amino-acid protein which shows significant homology in the N-terminal and C-terminal regions to five bacterial Fpg proteins. A nei partial deletion replacement mutant was constructed, and deletion of nei was confirmed by genomic PCR, activity analysis, and Western blot analysis. nth nei double mutants were hypersensitive to ionizing radiation and hydrogen peroxide but not as sensitive as mutants devoid of base excision repair (xth nfo). Single nth mutants exhibited wild-type sensitivity to X rays, while nei mutants were consistently slightly more sensitive than the wild type. Double mutants lacking both endonucleases III and VIII exhibited a strong spontaneous mutator phenotype (about 20-fold) as determined by a rifampin forward mutation assay. In contrast to nth mutants, which showed a weak mutator phenotype, nei single mutants behaved as the wild type.
Amino Acid Sequence↗
Simian virus 40 T antigen can regulate p53-mediated transcription independent of binding p53.
A simian virus 40 (SV40) T-antigen mutant containing only the N-terminal 136 amino acids, able to bind to Rb and p300 but not p53, partially inhibited p53-mediated transcription without affecting the ability of p53 to bind DNA. These results suggest that SV40 T antigen can regulate p53-mediated transcription either directly through protein-protein association or indirectly through interaction with factors which may function to confer p53-mediated transcription.
Animals↗
Responses of neurons in the inferior colliculus to binaural masking level difference stimuli measured by rate-versus-level functions.
The psychophysical detection threshold of a low-frequency tone masked by broadband noise is reduced by < or = 15 dB by inversion of the tone in one ear (called the binaural masking level difference: BMLD). The contribution of 120 low-frequency neurons (best frequencies 168-2,090 Hz) in the inferior colliculus (ICC) of the guinea pig to binaural unmasking of 500-Hz tones masked by broadband noise was examined. We measured rate-level functions of the responses to identical signals (So) and noise (No) at the two ears (NoSo) and to identical noise but with the signal inverted at one ear (NoS pi): the noise was 7-15 dB suprathreshold. The masked threshold was estimated by the standard separation, "D". The neural BMLD was estimated as the difference between the masked thresholds for NoSo and NoS pi. The presence of So and S pi tones was indicated by discharge rate increases in 55.3% of neurons. In 36.4% of neurons, the presence of So tones was indicated by an increase in discharge rate and S pi tones by a decrease. In 6.8% of neurons, both So and S pi tones caused a decrease in discharge rate. In only 1.5% of neurons was So indicated by a decrease and S pi by an increase in discharge rate. Responses to the binaural configurations were consistent with the neuron's interaural delay sensitivities; 34.4% of neurons showing increases in discharge rate to both So and S pi tones gave positive BMLDs > or = 3 dB (S pi tones were detected at lower levels than So), whereas 37.3% gave negative BMLDs > or = 3 dB. For neurons in which So signals caused an increase in the discharge rate and S pi a decrease, 72.7% gave positive BMLDs > or = 3 dB and only 4.5% gave negative BMLDs > or = 3 dB. The results suggest that the responses of single ICC neurons are consistent with the psychophysical BMLDs for NoSo versus NoS pi at 500 Hz, and with current binaural interaction models based on coincidence detection. The neurons likely to contribute to the psychophysical BMLD are those with BFs near 500 Hz, but detection of So and S pi tones may depend on different populations of neurons.
Animals↗
[Effects of lithium chloride and harringtonine on the differentiation, proliferation and c-myc proto-oncogene expression of HL-60 cells].
This research was to observe the effects of lithium chloride (LiCl) and Harringtonine (HT) on the proliferation and differentiation of HL-60 leukemia cells. The results obtained by liquid suspension culture, semi-solid colony culture and 3H-TdR incorporation into HL-60 cells indicated that different concentrations of LiCl (5-20 mmol/L) and HT (10(-8)-10(-5)mol/L) exerted the inhibitory effects in a dose-dependent manner on HL-60 cell proliferation respectively. When LiCl (10 mmol/L) and HT (10(-7) mol/L) were added together in the liquid culture or semi-solid culture of HL-60 cells, they showed much greater inhibitory effect than that by each agent separately. It was discovered that there was induction of the differentiation of HL-60 cells by lithium and HT and the induction of HL-60 cells differentiation by HT was markedly enhanced by the addition of low concentration of lithium. This work also showed that by treating HL-60 cells with lithium and HT, the expression of the c-myc proto-oncogene was markedly decreased as measured by RT/PCR-mRNA (P < 0.01). These findings provide some evidence of the mechanismcausing leukemic change and of the potential use of lithium and HT in the treatment of leukemia and in vitro purging of leukemic cells for autologous bone marrow transplantation.
Antineoplastic Agents↗
[The expression of hsp70 and BCL-2 genes in hippocampus of the rats exposed to cerebral ischemia and reperfusion].
In order to study the molecular mechanism of the selective vulnerability in central nervous system, the expression and distribution of hsp70 and BCL-2 gene were detected by using Northern blot analysis, in situ hybridization and histochemistry method in transient forebrain ischemia and reperfusion rats. It was found that hsp70 gene expression occurred and the synthesis of BCL-2 protein was inhibited in hippocampalCA1 region vulnerable to ischemia, while BCL-2 protein was stained strongly and the signals of hsp70 were not observed in CA3 region resistant to ischemia. The results indicate that the expression of hsp70 gene may be not only as a marker for neuron ischemia, but also play a protective role in the neuronal injury. BCL-2, meanwhile, may have neuro-protective effect on the ischemic neurons.
Animals↗