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Biomedical subjects

W Fang

Publications and source records attributed to W Fang.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Effect of TNF-alpha monoclonal antibody on tissue lipopolysaccharide-binding protein mRNA expression in rats after thermal injury].

OBJECTIVE: To explore the effects of tumor necrosis factor-alpha (TNF-alpha) monoclonal antibody (MAb) on tissue TNF-alpha and lipopolysaccharide-binding protein (LBP) mRNA expression, and multiple organ dysfunction in rats after thermal injury. METHOD: 24 male Wistar rats were subjected to a 35% total body surface area full-thickness thermal injury. RESULT: The tissue TNF-alpha and LBP mRNA expressions of liver, lung, intestine, and kidney were markedly increased (P < 0.05 approximately equal 0.01) after thermal injury. Treatment with TNF-alpha MAb could significantly lower TNF-alpha mRNA expression of lung, intestine and kidney, but had no effect on liver TNF-alpha mRNA expression (P > 0.05). Similarly, the tissue LBP mRNA expression also decreased significantly (36.0% - 72.9%), and returned to normal in lung, intestine and kidney. In addition, biochemical parameters including GPT, TBiL, BUN, CK-MB, and LDH were markedly elevated after thermal injury, and decreased significantly after treatment with TNF-alpha MAb. CONCLUSION: The increase of tissue TNF-alpha gene expression caused by thermal injury might be associated with a marked elevation of tissue LBP mRNA expression, which could contribute to the development of multiple organ dysfunction. The early use of TNF-alpha MAb seems to be effective in inhibiting significant LBP mRNA expression in various tissues and ameliorating multiple organ damage after major thermal injury.

Acute-Phase Proteins↗
PubMed1998

[Studies on the fine stereostructure of taxoids].

The anticancer drug taxol is a new type antimicrotubular drug. The structure-activity relationship study on taxol and its analogs has indicated the importance of the C13 side chain and the C4-C5-C20 epoxypropane group. The crystal structures of 4 taxoids having the basic skeleton with 5/7/6 membered ring and three types of 10 taxoids having the basic skeleton with 6/8/6 membered ring have been analyzed. The effects of the induction by different substructures at C4 on the stereostructures of taxoids were studied, and the relationship between the 6/8/6/4 skeleton and the anticancer activity was discussed from the crystallographic point.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[A study on the spectra of L-fucose].

The concentration of L-fucose will extraordinarily increase in urine in patients with early stage of cancer. It seems that this is a significant clue for early phase diagnosis of cancer. Unfortunately the sensitive detection of L-fucose is difficult. Thus we carried out researches on IR-spectrum, Raman spectrum, ultraviolet absorption spectrum and ultraviolet fluorescence spectrum. We compared the results from patients and healthy subjects. It is confirmed that the spectroscopic method, especially ultraviolet fluorescence spectrophotometry, may be suitable for early stage screening of some kinds of cancer. This test is rapid, inexpensive and painless.

Absorption↗
PubMed1997

Methyl-directed repair of mismatched small heterologous sequences in cell extracts from Escherichia coli.

The methyl-directed DNA repair efficiency of a set of M13mp18 heteroduplexes containing 1-8 or 22 unpaired bases was determined by using an in vitro DNA mismatch repair assay. The unpaired bases of each heteroduplex residing at overlapping recognition sites of two restriction endonucleases allow independent assay of repair on either DNA strand. Our results showed that the repair of small nucleotide heterologies in Escherichia coli extracts was very similar to base-base mismatch repair, being strand-specific and highly biased to the unmethylated strand. The in vitro activity was also dependent on products of mutH, mutL, mutS, and uvrD loci and was equally efficient on nucleotide insertions and deletions. The repair levels of small heterologies were affected by base composition of the heterologies. However, the extent of repair of heteroduplexes containing small heterologous sequences was found to decrease with an increase in the number of unpaired bases. Heteroduplexes containing an extra nucleotide of 22 bases provoked very low level of methyl-directed repair.

Bacterial Proteins↗
PubMed1997

Childhood-onset autosomal-dominant limb-girdle muscular dystrophy with cardiac conduction block.

We report childhood-onset autosomal-dominant limb-girdle muscular dystrophy (LGMD) in a Chinese family with complete atrioventricular conduction block in the adult members. Six patients, including 5 men and 1 woman with an age of onset from 3 to 7 years, were affected. The grandfather had exercise intolerance since childhood and complete heart block with pace-maker placement at age 52. Three siblings had proximal muscle weakness and/or wasting since age 5 and heart block in their 40s. Two grandsons at the ages 7 and 3 showed exercise intolerance, and proximal muscle weakness and wasting. Sinus bradycardia was present in the elder grandson. Muscle enzymes were elevated in 3, particularly in childhood. Muscle biopsies from the proband showed myopathic changes with fatty degeneration, whorled fibers, and rimmed vacuoles. In adult patients, muscle magnetic resonance imaging scans disclosed atrophic changes and fatty degeneration in the gluteal, quadriceps, adductors, hamstrings, gastrocnemius, and soleus muscles, while in child probands the early atrophic changes were seen in the gluteal and hamstrings muscles. We conclude that this distinct family is characterized by childhood-onset autosomal-dominant LGMD with heart block and that prevention of sudden death in these patients is important.

Adolescent↗
PubMed1997

Spontaneous spinal epidural haematomas with repeated remission and relapse.

We present a case of spontaneous spinal epidural haematoma (SSEH) with a rare clinical course of repeated spontaneous recovery and relapse. The patient suffered three episodes of upper-back pain of sudden onset followed by sensory and motor dysfunction after weight lifting. In the first two episodes, the neurological deficits recovered spontaneously and completely. In the last episode, paraplegia persisted even after emergency surgery. Serial studies with computed tomographic (CT) myelography and magnetic resonance imaging (MRI) demonstrated the remitting and relapsing course of the SSEHs. The possible causes of the SSEHs and the mechanisms of spontaneous recovery are discussed.

Diagnosis, Differential↗
PubMed1997

Giving selenium supplements to dairy cows strengthens the inflammatory response to intramammary infection and induces a growth-suppressing effect on mastitis pathogens in whey.

Supplementing the feed of selenium-deficient diary cows with selenium (Se)-yeast or selenite at a level of 0.2 p.p.m. induced self-cure of subclinical mastitis; the prevalence of quarters harbouring subclinical mastitis (bacteriological criteria) decreased to about one half during the 8 week supplementation period. Three phenomena became apparent to explain the beneficial effect of selenium on mastitis: 1. The recruitment of phagocytes to the infected milk compartment of the udder was improved due to Se-supplementation; the correlation between infection and the respective inflammatory response, as indicated by the somatic cell count (SCC) and the N-acetyl-beta-D-glucosaminidase activity (NAGase) of milk, was poor in selenium-deficient cows. Selenium supplementation significantly improved the correlation; 2. Selenium supplementation induced an unspecified antibacterial activity in milk lactoserum (whey), restricting in vitro growth of the mastitis pathogens Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae and Streptococcus uberis, bacterial growth rates in whey samples became inversely correlated with the respective blood glutathione peroxidase activities (GSH-Px); and 3. Selenium supplementation had an effect on redox activities and sulfhydryl activities in whey. These changes were correlated with in vitro bacterial growth rates.

Animals↗
PubMed1997

CD40 inhibits B cell apoptosis by upregulating bcl-xL expression and blocking oxidant accumulation.

Signaling through the CD40 receptor on human and murine B lymphocytes is necessary for germinal center formation and immunoglobulin class switching in vivo and rescues B cells from apoptosis triggered by cross-linking of surface immunoglobulin M in vitro. Ligation of CD40 on the immature mouse B cell line WEHI-231 with recombinant CD40 ligand (CD40L) was found to protect cells from apoptosis after gamma irradiation, as well as that following treatment with the sphingomyelin ceramide or compounds that deplete intracellular glutathione. CD40 signaling led to a rapid increase in the expression of the apoptosis inhibitory protein Bcl-xL. In addition, the apoptosis-induced accumulation of intracellular oxidants in WEHI-231 B cells was rapidly diminished by CD40 crosslinking. This antioxidant response was observed within 1 h and coincided with a preservation of intracellular thiols. These findings indicate that CD40 signaling induces a generalized cellular resistance to apoptosis characterized by an upregulation of Bcl-xL and changes in the intracellular redox potential.

Animals↗
PubMed1997

Peripheral neuropathy in mitochondrial encephalomyopathies.

Seven patients with mitochondrial encephalomyopathies were studied for peripheral neuropathy by clinical, electrophysiological and pathological examinations. The clinical manifestation of neuropathy varied from asymptomatic to mild and moderate sensorimotor symptoms with painful paresthesia. Five patients (2 with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, and 3 with myoclonic epilepsy and ragged-red fibers, MERRF) had clinical symptoms and signs of polyneuropathy associated mainly with decreased amplitudes of the compound muscle or nerve action potentials in an electrophysiological study indicating axonal degeneration. Sural nerve biopsy from 1 MERRF patient, also confirmed an axonal degeneration with reduction of large myelinated fibers. Mitochondrial DNA analysis of the sural nerve from this patient showed a point mutation from A to G transition at the nucleotide position 8344 with 80% mtDNA mutation. The results of this study suggest that peripheral neuropathy is not uncommon in mitochondrial encephalomyopathies and is predominantly due to axonal degeneration.

Adolescent↗
PubMed1997

[Interleukin-6 behaves as an autocrine growth stimulator for a human lung giant cell carcinoma cell line].

OBJECTIVE: To study the effect of interleukin-6 (IL-6) on the growth of human pulmonary giant cell carcinoma cell line PG in vitro. METHODS: IL-6 mRNA level was detected by means of reverse transcriptase polymerase chain reaction (RT-PCR) and IL-6 receptor (IL-6R) mRNA was analyzed using Northern blotting hybridization. The production of IL-6 was detected by bioactive assay. The biological role of IL-6 produced by PG cells was assessed with anti-IL-6 neutralizing antibodies. RESULTS: PG cells expressed IL-6R mRNA. Recombinant human IL-6 promoted the proliferation of PG cells. PG cells also expressed IL-6 mRNA and produced bioactive IL-6. Treatment of PG cells with anti-IL-6 antibodies resulted in reduced growth of PG cells. CONCLUSION: The results indicate that IL-6 behaves as an autocrine growth stimulator for PG cells in vitro.

Antibodies↗
PubMed1997

[Regulatory effects of cAMP analogs on growth and differentiation of metastatic human lung cancer cells].

OBJECTIVE: To study the effects of two cAMP analogs with different site-selectivity on growth and differentiation of metastatic human lung cancer cells. METHODS: The methods used include cell culture, in vitro invasion assay, soft agar colony formation assay, immunocytochemistry and electron microscopy. A metastatic human lung cancer cell line gwas treated with dibutyryl cAMP (db-cAMP, non-site-selective) or 8-chloro-cAMP (8-Cl-cAMP, site-selective for type II PKA). RESULTS: Treatment of PG cells with 1 mmol/L of db-cAMP for 7 days resulted in 48% growth inhibition, while treatment with 20 mumol/L of 8-Cl-cAMP gave 70% growth inhibition. The growth inhibitory effect of db-cAMP was shown to be reversible, while that of 8-Cl-cAMP was not. The ability of PG cells to penetrate matrigel-coated membrane and to form colonies in soft agar was also significantly inhibited by treatment with these two drugs. Microscopic observation showed that cells formed elongated cytoplasmic processes and increased expression of neuron-specific enolase as well as chromogranin after treatment. CONCLUSION: The objective to inhibit malignancy could be reached by activation of specific PKA with site-selective cAMP analogs.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1997

[Mutation and methylation of CDKN2 gene in human head and neck carcinomas].

OBJECTIVE: To study mutations of CDKN2 gene in human head and neck carcinomas (HNC) and to elucidate the role of this gene in tumorigenesis. METHODS: PCR-SSCP and sequencing techniques were used to detect mutations in fresh specimens from 36 HNC cases. Specimens from 20 cases were further analysed for methlyation status of the CpG islands in the first exon of the gene using restriction enzyme digestion plus Southern blotting analysis. RESULTS: CDKN2 gene mutations were detected in 4 HNC cases of which 2 were missense mutation and the other 2 were frameshift mutation. Methylation status analysis revealed that 8 out of 20 HNC cases had de novo methylation of CpG island within the first exon of CDKN2 gene. CONCLUSION: The results shown here suggest that in addition to gene mutation and deletion, de novo methylation of the CpG island may be a frequent event in human carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed1997

[Differential expression and response of growth factors in metastatic variants of human pulmonary giant cell carcinoma cell line].

OBJECTIVE: To study the difference in expression and response of certain growth factors between the two metastatic variants PGbE1 and PGLH7 of human pulmonary giant cell carcinoma, and the action of these growth factors on the metastasis of tumor cells. METHODS: RT-PCT was conducted to detect the expression of TGF alpha, TGF beta 1, IL-6, IL-8, bFGF and ANG, and the expression of receptors EGFR, IL-6R and IL-8R; 3H-TdR incorporation assay was used to determine the effects of recombinant TGF alpha, TGF beta 1 and IL-6 on the proliferation of the two cells. RESULTS: TGF alpha, EGFR, IL-6 and IL-6R were expressed at a higher level in PGbE1 cells than in PGLH7 cells. No significant differences were found in the expression of TGF beta 1, bFGF, IL-8, IL-8R and ANG between the two cells. Recombinant TGF alpha and IL-6 stimulated the proliferation of both cells, while TGF beta 1 had dual effects. CONCLUSION: TGF alpha, TGF beta 1, bFGF, IL-6, IL-8 and ANG may be involved in the autocrine regulation of the growth and proliferation of pulmonary giant cell carcinoma, TGF alpha and IL-6 may play an important role in the metastasis of the tumor cells.

Carcinoma, Giant Cell↗
PubMed1997

[Interleukin-6 functions as an autocrine growth stimulator for a human lung adenocarcinoma cell line PAa].

OBJECTIVE: To study the effect of interleukin-6(IL-6) on the growth of a human lung adenocarcinoma cell line PAa in vitro. METHODS: IL-6 receptor (IL-6R) mRNA level was detected by means of reverse transcription polymerase chain reaction (RT-PCR) and IL-6 mRNA was analyzed using Northern blotting hybridization. The production of IL-6 was detected by bioassay. The biological effect of IL-6 released by PAa cells was assessed with anti-IL-6 neutralizing antibodies. RESULTS: PAa cells expressed IL-6R mRNA. Recombinant human IL-6 stimulated the proliferation of PAa cells. PAa cells also expressed IL-6 mRNA and produced bioactive IL-6. Treatment of PAa cells with anti-IL-6 antibodies resulted in decreased growth of PAa cells. CONCLUSION: These results demonstrate that IL-6 acts as an autocrine growth stimulator for PAa cells in vitro.

Adenocarcinoma↗
PubMed1997

Resazurin reduction as a function of respiratory burst in bovine neutrophils.

OBJECTIVE: To determine whether the respiratory burst of neutrophils from bovine blood and milk can be analyzed by use of a fluorometric resazurin reduction assay. SAMPLE POPULATION: Neutrophils were obtained from EDTA-anticoagulated blood of 7 dairy cows. Neutrophils also were isolated from milk samples of a cow intramammarily challenge exposed with Escherichia coli lipopolysaccharide. PROCEDURE: The respiratory burst of neutrophils was analyzed in parallel, using the conventional luminol-enhanced luminometric procedure and a novel fluorometric procedure with resazurin as the fluorogenic substrate. Opsonized zymosan and phorbol myristate acetate were used as stimulants. The mechanism of the fluorescent response was analyzed, using metabolic inhibitors to various cell functions. Luminometry and fluorometry were carried out in parallel, using microtitration tray-reading instruments. RESULTS: Stimulation of neutrophils induced resazurin reduction to resorufin and a fluorescent response. The luminescent response was transient, but the fluorescent response (build-up of fluorescent resorufin) was cumulative. Therefore, a single end-point measurement can be used for the fluorometric assay. CONCLUSIONS: The proposed fluorometric microtitration tray technology is simple and has a high throughput capacity. The fluorometric and luminometric assays seem to have similar potential in the analysis of phagocyte functions.

Animals↗
PubMed1997

[Effects of TIMP-2 gene transfection on biological behaviors of a metastatic human lung carcinoma cell line].

OBJECTIVES: To explore the suppressive effects of tissue inhibitor of metalloproteinase 2 (TIMP-2) on malignant phenotype of human carcinoma cells and to evaluate its potential application in cancer gene therapy. METHODS: A man malian expression vector containing TIMP-2 cDNA was constructed and transfected into a metastatic human lung carcinoma cell line PG. In vitro and in vivo tests such as Northern blotting, immunohistochemistry as well as x enografting in nude mice experiment were used to analyse expression levels of TIMPs and MMPs, in vitro and in vivo behaviors of the tumor cells before and after the gene transfection. RESULTS: After transfection, the TIMP-2 mRNA expression was upregulated significantly. Changes, in some malignant phenotypes of the transfectants were seen. For instance, the abilities of in vitro invasion through Matrigel, colony formation on soft agar, tumorigenecity as well as spontaneous metastasis in nude mice were remarkably decreased. Immunohistochemical staining and in situ hybrydization showed that MMP2, MMP9, TIMP-1 and TIMP-2 were expressed by both tumor cells and stromal cells, with stronger staining at the site of tumor invasion. CONCLUSION: Up-regulation of TIMP-2 in tumor cells could suppress their expression of malignant phenotype and could be used for cancer therapy.

Animals↗
PubMed1996

Differential regulation of bcl-2 and bcl-x by CD3, CD28, and the IL-2 receptor in cloned CD4+ helper T cells. A model for the long-term survival of memory cells.

In this study, we examined the molecular signals that control apoptosis in cloned CD4+ helper T cells. Resting T cells were highly resistant to spontaneous death in the absence of exogenous stress, and they expressed low levels of bcl-x protein and no detectable bcl-2. Upon exposure to gamma radiation, resting cells rapidly underwent apoptotic death. Incubation with IL-2 prevented this cell death and led to a large increase in bcl-2 protein expression and only a modest up-regulation in bcl-x. The combination of anti-CD3 and anti-CD28 mAbs was also effective in protecting the cells against radiation-induced apoptosis; however, this protection was associated predominantly with bcl-x up-regulation, and only a small induction of bcl-2 protein was observed. Finally, cyclosporin A blocked both IL-2 secretion and bcl-2 induction in response to CD3 plus CD28 stimulation, suggesting a role for endogenous lymphokine production in the induction of bcl-2. These data support a model in which memory T cells remain resistant to apoptosis because intermittent contact with Ag-bearing APC and IL-2R occupancy result in the expression of the life-proteins bcl-2 and bcl-x.

Animals↗