Biomedical subjects

F Bai

Publications and source records attributed to F Bai.

At least 37 records · Page 2Linked to original sources

PubMed2001

[High concentration ethanol continuous fermentation using yeast flocs].

Continuous ethanol fermentation using yeast flocs was carried out in 4 air-lift suspended-bed bioreactors operated in series. Drafted by CO2, with complete recycle of ethanol distilled effluent broth and at the dilution rate of 0.2/h, the average ethanol concentration of the fermentation broth was 96.6 g/L, while the average concentration of residual total sugar was 4.1 g/L and residual reducing sugar was 1.2 g/L.

Bioreactors↗

PubMed2001

[The comparisons of fluorescence quenching between perylene and pyrene].

The fluorescence quenching of perylene and pyrene by dimethyl terephthalate (DMTP) and N,N-dimethylaniline (DMA) have been investigated. The results show that pyrene can form exciplex with DMTP or DMA at room temperature and perylene can only form exciplex with DMA. The fluorescence quenching date is in conformity with the Stern-Volmer equation: F0/F = 1 + KSV[Q] = 1 + Kq.tau 0[Q], the F0/F-[Q] straight lines are drawn. The Stren-Volmer constants and fluorescence quenching rate constants (KSV and Kq) are obtained. The Stern-Volmer quenching constants of pyrene is larger than that of perylene. The differences is due to the molecular structure of perylene which is not a typical large conjugated system and less coplanar configuration than pyrene.

Aniline Compounds↗

PubMed2000

Seeds induced to germinate rapidly by mentally projected 'qi energy' are apparently genetically altered.

Mentally controlled qi energy can induce crop seeds to sprout and root for several cm within about 20 min. The RAPD method was used to compare treated groups of wheat and pea seeds and their controls using 11 selected primers. Seven primers amplified polymorphisms in wheat seeds and 5 in pea seeds. It was thought preliminarily that qi energy changed the structure of a germination-correlated gene site speeding up expression and advancing it in time.

Germination↗

PubMed2000

Polycyclic aromatic hydrocarbon carcinogens increase ubiquitination of p21 protein after the stabilization of p53 and the expression of p21.

Polycyclic aromatic hydrocarbon carcinogens (PAHs) and their metabolites have been found to result in a rapid accumulation of p53 gene product in human and mouse cells. However, the induced p53 protein was reported to be transcriptionally inactive. In the present study, the induction of p53 target gene expression after the treatment with either benzo(a)pyrene (B[a]P) or 1-nitropyrene (1-NP) was investigated. A marked induction of messenger RNA (mRNA) expressions of Mdm2, Bax, and p21 was detected in wild-type p53-expressing cells after the treatment with either B[a]P or 1-NP, whereas no significant change in mRNA expression of these genes was observed in p53-negative and mutant cells. 1-NP activated the p21 promoter in a p53-dependent manner. Binding activity of p53 to a p53 consensus sequence increased after the treatment in wild-type p53-expressing cells. Nevertheless, the induced mRNA levels of the p21 did not result in a proportional p21 protein increase, indicating the possibility of post-transcriptional regulation of the protein. With the addition of MG-132, a proteasome inhibitor, to B[a]P or 1-NP treatments, both p21 and p53 protein levels were increased; however, the increase in p21 protein levels was significantly larger than the increase in p53 protein levels. PAHs treatment increased the level of ubiquitinated p21. These results suggest that the p21 product is degraded by the ubiquitin-proteasome system. We conclude that PAHs-induced p53 protein is transcriptionally active.

Benzo(a)pyrene↗

PubMed2000

[Treatment of bacterial peritonitis with dachengqi decoction and rhubarb in mice].

OBJECTIVE: To observe the antiseptic effect of Dachengqi Decoction (DCQD) or rhubarb, one of the ingredients of DCQD in mice. METHODS: The model mice were established by peritoneal injection of Escherichia coli (10(8)/ml) or Proteus vulgaris (10(6)/ml) respectively. DCQD or rhubarb was given from 2 days before to 2 days after modelling for preventing and treating. RESULTS: The mortality and bacteremia occurrence of the treatment group were significantly lower than those of the control group (P < 0.05). Both DCQD and rhubarb showed protective effect on Escherichia. coli or Proteus vulgaris infection in mice. The cardiac blood smear and culture of survival mice in prevention plus treatment group and model group showed negative (bacteria) results but those of dead mice showed positive result. CONCLUSION: DCQD and rhubarb have excellent bactericidal effect.

Animals↗

PubMed2000

[An ultrastructural observation on rat retina after photoreceptor cell implantation].

OBJECTIVE: To further study the retinal neuronal signal. METHODS: The Wistar/RCS (RCS rats are rats with hereditary photoreceptor degeneration) rats were respectively as donors/acceptors, and the retinal pathway was reconstructed with the technique of pure photoreceptor transplantation. The photoreceptor layer of the retina was obtained with the technique of retinal whittle by manual method or excimer laser. The specimens were got separately at 2 weeks and 1 month after the transplantation and studied under the light and transmission electron microscopes. RESULTS: Most transplanted photoreceptors with physical poles were lined up regularly between the retinal pigment epithelium (RPE) and inner nuclear layer. It was shown that in the new outer plexiform layer the relatively integral synapse and its interconnection were seen. CONCLUSION: The retinal neuronal pathway can be reconstructed by retinal transplantation.

Animals↗

PubMed2000

[Reclassification of Saccharomyces strains by comparative electrophoretic karyotyping].

The strains of Saccharomyces Meyen ex Reess preserved in China General Microbiological Culture Collection Center (CGMCC) were recharacterized and reidentified according to recent taxonomic improvement of the genus. The strains AS 2.100 (originally classified in S. cerevisiae), AS 2.1158(from former USSR and originally classified in S. exiguus) and AS 2.1555(from Australia and originally classified in S. uvarum) were found to be different from the standard descriptions of the species concerned in some physiological properties. Comparative CHEF electrophoretic karyotype analysis showed that the chromosomal DNA banding pattern of AS 2.100 was similar to that of the type strain of S. bayanus, while the electrophoretic karyotypes of AS 2.1158 and AS 2.1555 were similar to those of the type and authentic strains of S. cerevisiae. Therefore, AS 2.100 was reidentified as S. bayanus, and AS 2.1158 and AS 2.1555 were reclassified in the species S. cerevisiae.

Chromosome Banding↗

PubMed1999

Benzo[a]pyrene activates the human p53 gene through induction of nuclear factor kappaB activity.

p53 is known to be recruited in response to DNA-damaging genotoxic stress and plays an important role in maintaining the integrity of the genome. In the present study, the effect of a potent lung cancer carcinogen, benzo[a]pyrene (B[a]P) on p53 expression was investigated. We showed that exposure of A549 and NIH 3T3 cells to B[a]P resulted in an increase in p53 mRNA levels and in p53 promoter activation, indicating that B[a]P-induced p53 expression is partly regulated at the transcriptional level. The p53 promoter region which extends from -58 to -43, overlapping the kappaB motif, is essential for both the p53 basal promoter activity and p53 promoter activation induced by B[a]P. Nuclear factor kappaB (NF-kappaB) proteins have been revealed to be activated in B[a]P-induced p53 expression. Activated NF-kappaB complexes were shown to contain predominantly p50 and p65 subunit components in A549 cells and p65 subunit in NIH 3T3 cells. In addition, the overexpression of IkappaBalpha completely inhibited NF-kappaB activation, p53 promoter transactivation and the stimulatory effect on p53 transcription induced by B[a]P. We therefore conclude that B[a]P transcriptionally activates the human p53 gene through the induction of NF-kappaB activity.

3T3 Cells↗

PubMed1999

Glutathione and N-acetylcysteine conjugates of alpha-methyldopamine produce serotonergic neurotoxicity: possible role in methylenedioxyamphetamine-mediated neurotoxicity.

Direct injection of either 3,4-(+/-)-methylenedioxymethamphetamine (MDMA) or 3,4-(+/-)-methylenedioxyamphetamine (MDA) into the brain fails to reproduce the serotonergic neurotoxicity seen following peripheral administration. The serotonergic neurotoxicity of MDA and MDMA therefore appears to be dependent upon the generation of a neurotoxic metabolite, or metabolites, the identity of which remains unclear. alpha-Methyldopamine (alpha-MeDA) is a major metabolite of both MDA and MDMA. We have shown that intracerebroventricular (icv) injection of 2,5-bis(glutathion-S-yl)-alpha-methyldopamine [2, 5-bis(glutathion-S-yl)-alpha-MeDA] causes decreases in serotonin concentrations in the striatum, cortex, and hippocampus, and neurobehavioral effects similar to those seen following MDA and MDMA administration. In contrast, although 5-(glutathion-S-yl)-alpha-methyldopamine [5-(glutathion-S-yl)-alpha-MeDA] and 5-(N-acetylcystein-S-yl)-alpha-methyldopamine [5-(N-acetylcystein-S-yl)-alpha-MeDA] produce neurobehavioral changes similar to those seen with MDA and MDMA, and acute changes in brain 5-HT and dopamine concentrations, neither conjugate caused long-term decreases in 5-HT concentrations. We now report that direct intrastriatal or intracortical administration of 5-(glutathion-S-yl)-alpha-MeDA (4 x 200 or 4 x 400 nmol), 5-(N-acetylcystein-S-yl)-alpha-MeDA (4 x 7 or 4 x 20 nmol), and 2, 5-bis(glutathion-S-yl)-alpha-MeDA (4 x 150 or 4 x 300 nmol) causes significant decreases in striatal and cortical 5-HT concentrations (7 days following the last injection). Interestingly, intrastriatal injection of 5-(glutathion-S-yl)-alpha-MeDA or 2, 5-bis(glutathion-S-yl)-alpha-MeDA, but not 5-(N-acetylcystein-S-yl)-alpha-methyldopamine, also caused decreases in 5-HT concentrations in the ipsilateral cortex. The same pattern of changes was seen when the conjugates were injected into the cortex. The effects of the thioether conjugates of alpha-MeDA were confined to 5-HT nerve terminal fields, since no significant changes in monoamine neurotransmitter levels were detected in brain regions enriched with 5-HT cell bodies (midbrain/diencephalon/telencephalon and pons/medulla). In addition, the effects of the conjugates were selective with respect to the serotonergic system, as no significant changes were seen in dopamine or norepinephrine concentrations. The results indicate that thioether conjugates of alpha-MeDA are selective serotonergic neurotoxicants. Nonetheless, a role for these conjugates in the toxicity observed following systemic administration of MDA and MDMA remains to be demonstrated, and requires further experimentation.

3,4-Methylenedioxyamphetamine↗

PubMed1999

Granulocyte, granulocyte-macrophage, and macrophage colony-stimulating factors can stimulate the invasive capacity of human lung cancer cells.

We and other researchers have previously found that colony-stimulating factors (CSFs), which generally include granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF), promote invasion by lung cancer cells. In the present study, we studied the effects of these CSFs on gelatinase production, urokinase plasminogen activator (uPA) production and their activity in human lung cancer cells. Gelatin zymographs of conditioned media derived from human lung adenocarcinoma cell lines revealed two major bands of gelatinase activity at 68 and 92 kDa, which were characterized as matrix metalloproteinase (MMP)-2 and MMP-9 respectively. Treatment with CSFs increased the 68- and 92-kDa activity and converted some of a 92-kDa proenzyme to an 82-kDa enzyme that was consistent with an active form of the MMP-9. Plasminogen activator zymographs of the conditioned media from the cancer cells showed that CSF treatment resulted in an increase in a 48-55 kDa plasminogen-dependent gelatinolytic activity that was characterized as human uPA. The conditioned medium from the cancer cells treated with CSFs stimulated the conversion of plasminogen to plasmin, providing a direct demonstration of the ability of enhanced uPA to increase plasmin-dependent proteolysis. The enhanced invasive behaviour of the cancer cells stimulated by CSFs was well correlated with the increase in MMPs and uPA activities. These data suggest that the enhanced production of extracellular matrix-degrading proteinases by the cancer cells in response to CSF treatment may represent a biochemical mechanism which promotes the invasive behaviour of the cancer cells.

Adenocarcinoma↗

PubMed1999

Expression of p53 and glutathione S-transferase-pi relates to clinical drug resistance in non-small cell lung cancer.

To determine the predictive value of the expression of p53 and glutathione S-transferase-pi (GST-pi) with respect to chemotherapy response, immunostaining was performed on transbronchial biopsy specimens from previously untreated patients with non-small cell lung cancer. Of the 54 patients, 34 patients (63%) and 37 patients (69%) were positive for p53 and GST-pi, respectively. The response rates in the p53-positive and p53-negative group were 15 and 45%, and those in GST-pi-positive and GST-pi-negative groups were 16 and 47%, respectively. A multiple logistic regression analysis revealed that positive immunostaining for GST-pi was a significant risk factor for clinical chemotherapy resistance. The combination of these two markers was the most important independent factor in predicting a response to chemotherapy in multiple logistic regression analysis. Immunohistochemical expression of p53 and GST-pi was independently related to clinical chemoresistance in patients with non-small cell lung cancer. Combined use of these two biomarkers may be a useful predictor of clinical chemoresistance.

Adult↗

PubMed1999

[Effect of PCBs on mouse lung tumorigenesis induced by 1-nitropyrene: a preliminary report].

We have analyzed the effect of polychlorinated biphenyls (PCB, Kanechlor-400) on 1-nitropyrene (1-NP) induced lung tumor. Male A/J mice (6 weeks old) were used for the experiment. A total of 2.5 mg/kg PCB was administered intraperitoneally (PCB group), a total of 0.38 mmol/kg 1-NP was administered intraperitoneally for 17 times (1-NP group), PCB was administered followed by i.p. injection of 1-NP (PCB + 1-NP group), and only vehicle was administered (control group). The lung lesions induced were examined 18 weeks after the final treatment with 1-NP or vehicle. In control group, no neoplastic lesion in the lung was induced. In PCB group, only one lesion with adenoma was induced. In 1-NP group, various kinds of lung neoplastic lesions including hyperplasia, adenoma and adenocarcinoma were induced. In PCB + 1-NP group, both the number and size of tumors induced were significantly more than those in 1-NP group. In addition, the number of adenocarcinoma formed was more in PCB + 1-NP group than in 1-NP group. Each lesion was microdissected to collect and analyze DNA of the targeted tissue. K-ras gene mutation was detected in part of adenoma lesions and all the carcinoma lesions. The mutation was found in either 1-NP or PCB + 1-NP group, but not in control and PCB group. The pattern of K-ras mutation was CAA to CGA in codon 61 or GGT to GAT in codon 12. There was no difference in the pattern of K-ras mutation despite of the pretreatment with PCB. Although the present data are from small sample size, it was suggested that PCB may promote (but not initiate) 1-NP induced lung tumorigenesis, and may not induce K-ras mutation directly in the experimental system.

Adenocarcinoma↗

PubMed1999

[A study on transplantation of rat photoreceptor cell layer].

OBJECTIVE: To study the relationship between photoreceptors and other layers of the retina in the aspects of anatomical structure, physiology, pathology, etc. METHODS: RCS rats were used as host animals, and the pure cone and rod layer of the donor retina was prepared from Wistar rat and was transplanted under the host retina where the cones and rods were degenerated. RESULTS: After 2 weeks of transplantation, the retinas of the host rats were reattached, and the transplanted cells were survival. The transplanted cells were in the subretinal space between the retinal pigment epithelium (RPE) and the inner unclear layer, and they had the staining characteristics similar to that of the normal control photoreceptors. CONCLUSION: In the animal model of photoreceptor cell layer transplantation, the transplanted cells possess normal anatomical location and are connected with RPE and inner nuclear layer. The results provide a new route to investigate the re-establishment of anatomical association with the optic nerve and the physiological activity of the nerve.

Animals↗

PubMed1999

[Industrial scale-up of continuous ethanol fermentation using yeast flocs].

Inducing yeast cells to self-flocculate as a cell immobilization method, an industrial scale-up plant composed of 4 air-lift suspended-bed bioreactors in parallel and with a total volume of 400 m3 was established and operated. During a more than 6 months continuous operation, the effluent contained ethanol of 70-80 g/L and residual sugar less than 5 g/L and the ethanol productivity of 7-8 g/L.h-1 was achieved.

Bioreactors↗

PubMed1998

Promoter activation and following induction of the p21/WAF1 gene by flavone is involved in G1 phase arrest in A549 lung adenocarcinoma cells.

Flavonoids are present in many plants including edible fruits and vegetables. Recently, many of the biological activities of flavonoids have been elucidated. Flavone is a well known flavonoid, and many of its derivatives have been shown to have anti-proliferative effects on several cancer cells. We report here that flavone can effectively inhibit the cell growth of human lung adenocarcinoma A549 cells in a dose-dependent manner, and 100 microM flavone causes cell cycle arrest at the G1 phase. As a mechanism underlying the cell cycle arrest, flavone markedly increases the mRNA and protein levels of a universal inhibitor of cyclin-dependent kinase, p21/WAF1, and inhibits phosphorylation of retinoblastoma (RB) protein. Although A549 cells possess wild-type p53, flavone does not induce the p53 protein, suggesting that p21/WAF1 induction is p53-independent. In addition, 100 microM flavone significantly increases the promoter activity of the p21/WAF1 gene by 5-fold. These results suggest that the G1 phase arrest by flavone is due to p53-independent transcriptional induction of the p21/WAF1 gene and the subsequent dephosphorylation of RB protein.

Adenocarcinoma↗

PubMed1998

[A study of genetic patterns of idiopathic epilepsy].

OBJECTIVE: To explore genetic patterns of idiopathic epilepsy (IEP). METHODS: Using familial analysis, tests for multifactorial inheritance and segregation analysis, we studied 210 pedigrees with IEP found in a population survey in Shangdong province. RESULTS: The genetic pattern of IEP is not polygenic but is mainly influenced by autosomal recessive disorders. The results of segregation analysis indicate that the genetic pattern of U*U multiplex families and U*A group is autosomal recessive. Only a few cases in U*U group may accept the assumption of autosomal recessive inheritance while the other are sporadic cases. The frequency of sporadic cases is approximately 78.5%. Genetic heterogeneity may influence U*U(f) group and U*U group. CONCLUSION: Further and careful empirical scrutiny of U*U(f) group and the sporadic cases in U*U group offers the best hope for getting a clear understanding of genetic patterns and mechanisms in IEP.

Epilepsy↗

PubMed1998

Ki-ras mutation and cell proliferation of lung lesions induced by 1-nitropyrene in A/J mice.

In this study, lung lesions were found in male A/J mice 24 wk after intraperitoneal injection of 1-nitropyrene (1-NP). The lesions were classified into three categories: alveolar/bronchiolar hyperplasia, adenoma, and adenocarcinoma. The proliferation kinetics of cells in the lesions were evaluated by assessing proliferating cell nuclear antigen (PCNA) expression and silver-staining nucleolar organizer regions (AgNORs). Furthermore, the role of the Ki-ras gene in tumorigenesis was studied by detecting point mutations in Ki-ras codons 12, 13, and 61 by polymerase chain reaction and sequence analysis. The PCNA-positive rates (+/- standard deviations) in various samples were as follows: 0% for specimens from six untreated animals and six uninvolved areas, 4.26 +/- 3.94% for 19 hyperplasias (hyperplasias vs normal lung tissue, P < 0.01), 13.24 +/- 6.35% for 25 adenomas (adenomas vs hyperplasias, P < 0.01), and 38.0 +/- 9.63% for four adenocarcinomas (adenocarcinomas vs adenomas, P < 0.01). The corresponding mean AgNOR scores were as follows: 1.10 +/- 0.05 for the untreated animals, 1.32 +/- 0.09 for the uninvolved areas, 1.72 +/- 0.59 for the hyperplasias (hyperplasias vs normal lung tissue, P > 0.05), 2.74 +/- 0.70 for the adenomas (adenomas vs hyperplasias, P < 0.01), and 5.22 +/- 0.62 for the adenocarcinomas (adenocarcinomas vs adenomas, P < 0.01). Ki-ras gene mutations were identified in three of four (75%) adenocarcinomas, six of 23 (26%) adenomas, and two of 17 (12%) hyperplasias. No mutations were found in normal lung tissue. The most frequent Ki-ras mutation was an arginine (CGA)AT --> GC transition at codon 61 in exon 2. The PCNA-positive rates and AgNOR scores of cases with Ki-ras mutations were higher than those without an identified mutation (P < 0.05). Ki-ras mutations at codon 61 (Arg) may therefore influence the growth or development of 1-NP-induced lung lesions in A/J mice.

Adenoma↗

PubMed1998

G-CSF increases secretion of urokinase-type plasminogen activator by human lung cancer cells.

We reported previously that granulocyte colony-stimulating factor (G-CSF) can promote the invasion of human lung cancer cell lines in vitro. However, the exact mechanism of its stimulatory effect on invasion remains to be elucidated. In the present study we mainly focused our attention on the components of the plasminogen activation system in human lung cancer cell lines, because of the central role that plasminogen activators play in regulating extracellular proteolysis. We showed that G-CSF induced a dose-dependent increase in the urokinase-type plasminogen activator (uPA) activity in the conditioned medium of a PC-9 lung cancer cell line. When the amounts of uPA activity were quantitated by densitometry, we found that even at a concentration of 0.01 microg/ml, G-CSF had a stimulatory effect on the uPA release, while high concentrations caused a 3.6-fold increase at a maximum concentration of 1 microg/ml. A Western blot analysis of the conditioned medium confirmed the findings observed in a zymographic analysis. The observed increase in uPA protein was paralleled by a significant increase in the uPA mRNA levels after treatment with G-CSF. However, our experiments failed to identify any alteration in the plasminogen activator inhibitor (PAI) secretion caused by G-CSF. In addition, we also found the expression of G-CSF receptor by PC-9 cells, suggesting the possible pathway activated by G-CSF.

Dose-Response Relationship, Drug↗