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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 127 records · Page 7Linked to original sources
PubMed2001

Transcriptional activation of deoxyribonucleic acid polymerase alpha gene expression in MCF-7 cells by 17 beta-estradiol.

Treatment of MCF-7 human breast cancer cells with 17beta-estradiol (E(2)) results in increased DNA synthesis and cell proliferation and enhanced enzyme activities associated with purine/pyrimidine biosynthesis. The mechanism of enhanced DNA polymerase alpha activity was investigated by analysis of the promoter region of this gene. E(2) induced luciferase (reporter gene) activity in MCF-7 cells transfected with pDNAP1, pDNAP2, and pDNAP3 containing -1515 to +45, -248 to +45 and -116 to +45 inserts from the DNA polymerase alpha gene promoter, whereas no induction was observed with pDNAP4 (-65 to +45 insert). The induction response was dependent on cotransfection with estrogen receptor alpha (ER(alpha)), and transactivation was also observed with a mutant ER(alpha) that did not express the DNA-binding domain. Subsequent functional, DNA binding, and DNA footprinting studies showed that a GC-rich region at -106 to -100 was required for E(2)-mediated transactivation, and Sp1 protein, but not ER(alpha), bound this sequence. Transcriptional activation of DNA polymerase alpha by E(2) is associated with ER(alpha)/Sp1 action at a proximal GC-rich promoter sequence, and this gene is among a growing list of E(2)-responsive genes that are induced via ER(alpha)/Sp1 protein interactions that do not require direct binding of the hormone receptor to DNA.

Breast Neoplasms↗
PubMed2001

Multimeric connexin interactions prior to the trans-Golgi network.

Cells that express multiple connexins have the capacity to form heteromeric (mixed) gap junction hemichannels. We used a dominant negative connexin construct, consisting of bacterial beta-galactosidase fused to the C terminus of connexin43 (Cx43/beta-gal), to examine connexin compatibility in NIH 3T3 cells. Cx43/beta-gal is retained in a perinuclear compartment and inhibits Cx43 transport to the cell surface. The intracellular connexin pool induced by Cx43/beta-gal colocalized with a medial Golgi apparatus marker and was readily disassembled by treatment with brefeldin A. This was unexpected, since previous studies indicated that Cx43 assembly into hexameric hemichannels occurs in the trans-Golgi network (TGN) and is sensitive to brefeldin A. Further analysis by sucrose gradient fractionation showed that Cx43 and Cx43/beta-gal were assembled into a subhexameric complex. Cx43/beta-gal also specifically interacted with Cx46, but not Cx32, consistent with the ability of Cx43/beta-gal to simultaneously inhibit multiple connexins. We confirmed that interactions between Cx43/beta-gal and Cx46 reflect the ability of Cx43 and Cx46 to form heteromeric complexes, using HeLa and alveolar epithelial cells, which express both connexins. In contrast, ROS osteoblastic cells, which differentially sort Cx43 and Cx46, did not form Cx43/Cx46 heteromers. Thus, cells have the capacity to regulate whether or not compatible connexins intermix.

3T3 Cells↗
PubMed2001

Transcriptional activation of heat shock protein 27 gene expression by 17beta-estradiol and modulation by antiestrogens and aryl hydrocarbon receptor agonists.

Heat shock protein 27 (Hsp 27) is expressed in mammary tumors and may play a role in tumor growth and response to anti-neoplastic drug therapy. 17beta-Estradiol (E2) induces Hsp 27 mRNA levels in MCF-7 human breast cancer cells, and we have investigated the comparative inhibitory mechanisms using the aryl hydrocarbon receptor (AhR) agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the direct-acting antiestrogen ICI 164,384. TCDD inhibited E2-induced Hsp 27 gene expression and analysis of the Hsp 27 gene promoter showed that the inhibitory response was associated with AhR interactions with a pentanucleotide motif at -3 to +2 in the promoter that corresponded to the core sequence of a dioxin responsive element. In contrast, ICI 164,384 induced Hsp 27 gene expression and reporter gene activity in MCF-7 cells and this represents one of the few examples of the estrogen receptor-alpha (ERalpha) agonist activity of the 'pure' antiestrogen ICI 164,384.

Base Sequence↗
PubMed2001

Cloning of deleted sequences (CODE): A genomic subtraction method for enriching and cloning deleted sequences.

The deletion of specific genomic sequences is believed to influence the pathogenesis of certain diseases such as cancer. Identification of these sequences could provide novel therapeutic avenues for the treatment of disease. Here, we describe a simple and robust method called cloning of deleted sequences (CODE), which allows the selective cloning of deleted sequences from complex human genomes. Briefly, genomic DNA from two sources (human normal and tumor samples) was digested with restriction enzymes (e.g., BamHI, BglII, and BclI), then ligated to special linkers, and amplified by PCR. Tester (normal) DNA was amplified using a biotinylated primer and dNTPs. Driver (tumor) DNA was amplified using a non-biotinylated primer, but with dUTP instead of d7TP After denaturation and hybridization, all the driver DNA was destroyed with uracil-DNA glycosylase (UDG), and all imperfect hybrids were digested with mung bean nuclease. Sequences deleted from the driver DNA but present in the tester DNA were purified with streptavidin magnetic beads, and the cycle was repeated three more times. This procedure resulted in the rapid isolation and efficient cloning of genomic sequences homozygously deleted from the driver DNA sample, but present in the tester DNA fraction.

Base Sequence↗
PubMed2001

Islet amyloid develops diffusely throughout the pancreas before becoming severe and replacing endocrine cells.

Islet amyloid occurs in >90% of type 2 diabetic patients and may play a role in the pathogenesis of this disease. To determine whether islet amyloid occurs diffusely throughout the pancreas, whether it affects islets equally, and whether it decreases islet endocrine cells, we characterized islet amyloidosis by computerized fluorescence microscopy in transgenic mice that develop typical islet amyloid. These mice produce the unique amyloidogenic component of human islet amyloid, human islet amyloid polypeptide (hIAPP). The prevalence of amyloid (number of islets containing amyloid/total number of islets x 100) and the severity of amyloid (Sigmaamyloid area/Sigmaislet area x 100) were found to be uniform throughout the pancreas. Furthermore, a high prevalence of amyloid was observed in islets when the severity of amyloid was only 1.5% of the islet area, suggesting a diffuse distribution of amyloid from the very early stages of islet amyloidosis. In 12 hIAPP transgenic mice with an amyloid severity of 9.6 +/- 3.4%, the proportion of islets composed of beta- and delta-cells was reduced in the transgenic mice compared with 6 nontransgenic mice that do not develop amyloid (beta-cells: 62.9 +/- 3.1% vs. 75.5 +/- 0.9%, P = 0.02; delta-cells: 2.8 +/- 0.5% vs. 4.4 +/- 0.4%, P = 0.05), whereas the proportion of islets composed of alpha-cells did not significantly differ between the two groups of mice. In the individual islets in these transgenic mice, amyloid severity was inversely correlated with beta-cell, (r = -0.59, P < 0.0001), alpha-cell (r = -0.32, P < 0.0001), and delta-cell (r = -0.25, P < 0.0001) areas. In conclusion, islet amyloidosis occurs uniformly throughout the pancreas, affecting all islets before becoming severe. A reduction in islet endocrine mass starts at this early stage of islet amyloid development and progresses as amyloid mass increases.

Amyloid↗
PubMed2001

[Effects of heat shock protein 70 overexpression on apoptosis of K562 cell caused by hyperthermia].

In order to observe the effects of heat shock protein 70(HSP70) on the apoptosis of K562 cell caused by hyperthermia, HSP70 was induced by pre-heating K562 cells at 40 degrees C and the levels of HSP70 were detected by RT-PCR. Cell apoptosis caused by hyperthermia at 43 degrees C was observed by Fluid cytometry (FCM) DNA content analyses. The results showed that HSP70 increased with the prolong of pre-heating time and reached the top level on pre-heating for 120 min and lasted for several hours. A lower apoptosis rate and less DNA ladder forming in the pre-heated cells than those not pre-heated. It is concluded that the higher expression of HSP70 induced by pre-heating treatment could inhibited the apoptosis caused by hyperthermia.

Apoptosis↗
PubMed2001

Assessing sediment contamination in estuaries.

Historic and ongoing sediment contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine sediments cannot be treated as either fresh or marine sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, sediment quality values, interstitial water chemistry), biological surveys, and whole sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine sediment toxicity tests available. Specific recommendations are made to address these and other issues.

Animals↗
PubMed2001

[Genotype polymorphism and its implications of mannose-binding protein allele in 5 Chinese nationalities].

OBJECTIVE: To detect the genotypes and sequences of the exon 1 of human mannose-binding protein (MBP) allele in 5 Chinese nationalities. METHODS: The genotypes of MBP gene of 5 Chinese nationalities were detected by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The exon 1 of the MBP gene of 22 Chinese Hans was analyzed by using ABI 310 genetic analyzer. RESULTS: The DNA sequences of exon 1 of Chinese MBP gene were acquired. The allele frequencies of the codon 54 of the MBP gene (MBP-54) of 5 Chinese nationalities were 0.181(Hans), 0.128(Uygurs), 0.181(Mongols), 0.179(Tibetans) and 0.181(Yis). The allele distribution for MBP-54 mutation of 5 Chinese nationalities was in good agreement with Hardy-Weinberg equilibrium. Compared with the Hans, Uygurs had a lower MBP-54 mutation rate. There were no differences in the allele frequencies between the chronic hepatitis B patients and health controls in Chinese Hans. The mutations of the codons 52 and 57 were not detected in this study. CONCLUSION: A higher prevalence of MBP-54 mutation was found in 5 Chinese nationalities, MBP-54 mutation was not associated with the persistence of hepatitis B.

Adolescent↗
PubMed2001

[Cloning and expressing of an anti-CD5 single chain antibody].

Novel anti-CD5 single-chain fragment of variable domain (ScFv) was cloned and expressed. Anti-CD5 ScFv was constructed with cDNA fragments of heavy and light variable regions (VH and VL) which were reverse-translated from poly (A) mRNA of hybridoma cells producing anti-CD5 McAb. By phage displaying, ScFv in form of ScFv-g3p fusion protein was panned based on its binding capacity to the CD5 antigens on the cell surface of Molt-4 cells. Assayed by the cell-ELISA, 4 clones were found to have high affinity to CD5 antigen. DNA sequencing confirmed that the VH fragment is 339 base pairs, the VL 300 bp, and the ScFv belongs to the mice gene family. In E. coli HB2151 the soluble ScFv-CD5 was expressed mainly in the periplasm.

Animals↗
PubMed2001

[Effects of chemical agents on the prevention of fungal contamination during household wheat storage in Cixian county].

OBJECTIVE: To evaluate the effectiveness of several commercial chemical agents (DMF, AP and Chumeijing) on the prevention of fungal contamination in household storage of wheat in Cixian county. METHODS: The antifungal agents tested include dimethyl fumarate, DMF, aluminium phosphide, AP and Chumeijing (a Chinese product comprised of propionic acid, formic acid, sorbic acid and fumaric acid). The chemicals were applied in the wheat containers in the rural households. The fungal contamination and the inhibitory effects on fungal growth in wheat were measured by fungal isolation, culture, identification and count. RESULTS: The fungal contamination in the household wheat before using fungicides were quite common, with an overall contamination rate of 67.5% to 100%. The application of the three chemical fungicides effectively reduced fungal contamination in household stored wheat, and the effective rate for DMF, AP, AMF + AP and Chumeijing was 91.2%, 85.2%, 100% and 100% respectively, while the rate of fungi growth inhibition was (61.9 +/- 21.6)%, (64.0 +/- 21.6)%, (72.5 +/- 18.0)% and (63.1 +/- 24.3)% respectively. CONCLUSION: DMF, AP and Chumeijing are all effective in the prevention of fungal contamination for household stored wheat in Cixian county. AP is not recommended owing to its higher toxicity, compared with the other chemicals tested.

Acids, Acyclic↗
PubMed2001

[Genotyping of HIV resistant alleles in indigenous Tibetan ethnic group of China: low frequency of CCR5triangle32 and high frequency of CCR2b-64I alleles].

OBJECTIVE: To investigate the allelic polymorphism of CCR5triangle32, CCR5m303, CCR2b-64I and SDF1-3'A in Tibetan population in Lasa area of China. METHODS: The genomic DNA samples from 330 Tibetan subjects' whole blood samples were purified by use of QIAgen Blood Kit and identified by PCR or PCR-RFLP analyses. RESULTS: The mutation frequencies of CCR5triangle32 and CCR5m303 alleles were lower than 0.15%, and those of CCR2 b-64I and SDF1-3'A alleles were 29.42% and 19.24% respectively in the study samples. The allelic polymorphisms of the four alleles of Tibetan population were similar to those of Chinese Han population. Genotype distribution of the four alleles was in accordance with Hardy-Weinberg equilibrium. The above results suggest that Tibetan population may be relatively susceptive to HIV-1. CONCLUSION: The Chinese Tibetan may have a lower frequency of CCR5triangle32 and a higher frequency of CCR2b-64I allele, compared with Caucasian.

Adolescent↗
PubMed2001

[Adenovirus-mediated transfer of human wild-type p53, GM-CSF, and B7-1 genes efficiently produces growth suppression and apoptosis of hepatocellular cells in vitro].

OBJECTIVE: To investigate the tumor suppressor activity of recombinant adenovirus vector expressing the human wild-type p53, GM-CSF, and B7-1 proteins (designated as BB-102) in human hepatocellular carcinoma cells (HCC) in vitro. METHODS: The wild-type p53 BEL-7402, mutant p53 HLE, and HuH-7 HCC cell lines were infected with BB-102 at MOI of 50 in vitro. Immunohistochemical assay was used to determine p53 expressed by BB-102. Tumor suppressor activity of the expressed p53 was identified by terminal deoxynucleotidy I transferase (TdT) assay in BB-102-infected HCC cell lines. RESULTS: p53 protein was found to express in a dose-dependent manner in BB-102-infected HCC cell lines. The proliferation of HCC cell lines were suppressed significantly at the average rates of 58.5%, 81.5%, and 71.1% for BEL-7402, HLE, and HuH-7 respectively from 4 to 10 days, accompanying inducing apoptosis in BB-102-infected HCC cell lines. CONCLUSIONS: Besides the expression of B7-1 and GM-CSF, BB-102 is able to express p53 protein in independent manner and exerts its anti-tumor activity, which suggests that BB-102 may be useful for gene therapy against HCC in vivo.

Adenoviridae↗
PubMed2001

Genotypes and polymorphisms of mutant CCR5-delta 32, CCR2-64I and SDF1-3' a HIV-1 resistance alleles in indigenous Han Chinese.

OBJECTIVE: To evaluate the frequencies and polymorphisms of CCR5-delta 32, CCR2-64I and SDF1-3' A alleles conferring resistance to HIV-1 infection in Chinese population from Han ethnic origin. METHODS: This cohort was comprised of 1251 subjects (915 men and 336 women) aged 15-80 years and none was HIV-1 positive. Genotyping of allelic CCR5-delta 32, CCR2-64I and SDF1-3' A variants was performed using PCR or PCR/RFLP assay, and further confirmed by direct DNA sequencing. RESULTS: Our finding shows that the delta 32 deletion mutation in the CCR5 gene does occur in this population and can be inherited in a Mendelian fashion in indigenous Han Chinese at a very low frequency of 0.00119 (n = 1254). The frequencies of mutant CCR2-64I and SDF1-3' A alleles were 0.20023 (n = 1251) and 0.2873 (n = 893), in this population, which are higher than those found in American Caucasians. Furthermore the polymorphisms of CCR2-64I and SDF1-3' A alleles in the Han Chinese population were different from those in American Caucasians. Statistical analysis showed that the genotype distribution of CCR5-delta 32, CCR2-64I and SDF1-3' A alleles was in equilibrium according to the Hardy-Weinberg equation. CONCLUSION: The CCR5-delta 32 mutation may not be a major resistant factor against HIV-1 infection in indigenous Han Chinese. The significance of higher frequencies of CCR2-641 and SDF1-3' A alleles (0.20023 and 0.2791) in the Han population remains to be clarified in HIV-1-positive carriers and AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Mortality patterns in Malaysian systemic lupus erythematosus patients.

A retrospective analysis of the case records of 494 systemic lupus erythematosus (SLE) patients under follow-up at University Hospital, Kuala Lumpur during 1976-1990 was performed. Overall mortality was 20.2% (100 patients). The causes of death were infection (30%), renal (15%), respiratory (14%), neurological (5%), cardiovascular (7%), other causes (2%) and unknown (27%). Active SLE was a contributing factor in 19% of the deaths. The patients who died had significantly more renal disease, neurological disease, serositis or thrombocytopenia by the end of the first year of disease compared to the survivors. As in other series, infection and active SLE remain important causes of death.

Adult↗
PubMed2001

Effect of phenolic alkaloids from Menispermum dauricum on myocardial-cerebral ischemia-reperfusion injury in rabbits.

AIM: To explore the mechanism underlying the effect of phenolic alkaloids from Menispermum dauricum (PAMd) on simultaneous myocardial-cerebral ischemia-reperfusion injury in rabbits. METHODS: Both left anterior descending coronary artery and bilateral carotid arteries were occluded to induce myocardial-cerebral ischemia-reperfusion injury in rabbits. At 30 min after ischemia, the occlusion was removed and shed blood was rapidly reinfused. Two mL of blood was taken fr om femoral artery at 10 min before ischemia, 1, 10, and 30 min after ischemia, and 1, 10, 30, 60, 120, 180, and 240 min after reperfusion. Each rabbit was sacrificed at the end of reperfusion, and left ventricle, hippocampus, cortex, and cerebellum were taken out. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined. RESULTS: At 10 min after reperfusion, MDA content in serum was significantly higher and SOD activity was lower in ischemia-reperfusion (I-R) group than those of control group (P < 0.05). After administration of PAMd, MDA content was lower and SOD activity was higher in serum than those of I-R group (P < 0.05). Both MDA content and SOD activity in tissues had the similar results with those in serum. CONCLUSION: PAMd could attenuate the injury induced by lipid peroxidation and enhance the activity of SOD, thus PAMd might play a protective role in simultaneous myocardial-cerebral ischemia-reperfusion injury.

Alkaloids↗
PubMed2001

[Microsurgical anatomy of intracranial segment of facial nerve].

OBJECTIVE: To study the microsurgical anatomy of intracranial segment of facial nerve so as to provide anatomic parameters for clinical operation. METHODS: Ten adult cadavers were fixed and perfused with color silicon. Facial nerves of these cadavers were observed and measured under operative microscope according to lateral cranial base operative approach. Ten dry skulls were dissected to observe the relationships of osseous structures. The anatomic relationship and data of different segment of facial nerve were obtained respectively. RESULTS: The facial nerve was divided into five segments, namely, cerebellopontine angle segment, internal acoustic meatus segment, labyrinthine segment, tympanum segment and mastoid segment. The cerebellopontine angle segment and internal acoustic meatus segment paralleled the vestibulocochlear nerve. The labyrinthine aegment is the finest and shortest with the lebgth of 3.8 mm +/- 0.7 mm. The tympanum segment is closely related with osseous labyrinth. The mastoid segment, 15.5 mm +/- 1.9 mm long, leaves the cranium from stylomastoid foramen. CONCLUSION: Facial nerve can be located with choroid plexus of the fourth ventricle in retrosigmoid approach. Arcuate eminence and greater superficial petrosal nerve are important mark to locate internal acoustic meatus segment and labyrinthine segment in antepetrosal approach. Tympanum segment may be exposed on the surface of petrous bone in some cases. The line between lateral semicircular canals and crista of digastric muscle is the mark of mastoid segment.

Adult↗