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B He

Publications and source records attributed to B He.

At least 37 records · Page 2Linked to original sources
PubMed1996

Analysis of the cellular origin of hepatocellular carcinoma by p53 genotype.

The polymerase chain reaction and HaeIII enzymatic digestion were used to study the seventh exon of the p53 gene in 29 primary and recurrent hepatomas in paraffin-embedded samples from 11 patients. The mutation rate of the p53 gene and its genotypes in samples of primary and recurrent tumours and multiple nodules were investigated. The cellular origins of hepatocellular carcinoma were analysed by p53 genotype. p53 mutation rates were found to be 69.0% (20/29) in the primary and recurrent tumours, 58.8% (10/17) in tumours with a single nodule and 83.3% (10/12) in tumours with multiple nodules. The p53 genotypes were found to be different in 6 pairs of primary and recurrent tumours, and another 5 pairs had the same p53 genotypes. The samples with multiple nodules in the same patients had the same p53 genotypes. Seven recurrences were of multicentric origin and four were of unicentric origin. It is suggested that the recurrent lesions developed from both unicentric and multicentric origins.

Adult↗
PubMed1996

Augmented expression of tumour necrosis factor-alpha and lymphotoxin in mononuclear cells in multiple sclerosis and optic neuritis.

The involvement of proinflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and lymphotoxin (LT) in multiple sclerosis is suggested by the parallel occurrence of these proinflammatory cytokines in acute and chronic active multiple sclerosis brain lesions. We describe the use of in situ hybridization with radiolabelled cDNA oligonucleotide probes to detect and enumerate TNF-alpha and LT mRNA expressing mononuclear cells without culture, and after culture in the presence of myelin basic protein (MBP), control antigens or without antigen. Compared with patients with aseptic meningo-encephalitis, non-inflammatory neurological diseases and healthy controls, the multiple sclerosis patients had elevated numbers of TNF-alpha and LT mRNA expressing mononuclear cells in blood when enumerated without previous culture, and also after culture with MBP. The MBP-induced upregulation of TNF-alpha and LT was major histocompatibility complex (MHC) class II molecule dependent. Tumour necrosis factor-alpha mRNA expressing mononuclear cells were further enriched in the multiple sclerosis patients' CSF. Positive correlations were observed in multiple sclerosis between TNF-alpha and LT mRNA expressing blood mononuclear cells, MBP-reactive TNF-alpha and LT mRNA expressing cells, and TNF-alpha and interferon-gamma (INF-gamma) mRNA expressing mononuclear cells. Upregulation of TNF-alpha correlated positively with exacerbation, enhanced disability and the secondary progressive phase of multiple sclerosis. Patients with optic neuritis, in many instances representing very early multiple sclerosis, had TNF-alpha and LT positive blood mononuclear cells that were elevated to the same extent as patients with clinically definite multiple sclerosis. The findings support the hypothesis that TNF-alpha and LT play a harmful role in the development of multiple sclerosis and suggest that TNF-alpha could be useful as a disease activity marker in multiple sclerosis.

Adult↗
PubMed1996

Induction of interleukin (IL)-8 gene expression by respiratory syncytial virus involves activation of nuclear factor (NF)-kappa B and NF-IL-6.

Respiratory syncytial virus (RSV) preferentially infects respiratory epithelium and is an important cause of lower respiratory tract infections in young children. RSV induces the production of interleukin (IL)-8 in airway epithelial cells; however, the mechanism of this induction is not known. To define the mechanism by which RSV induces IL-8 gene activation, A549 epithelial cells were transfected with plasmids containing serial deletions of the 5'-flanking region of the IL-8 gene and then exposed to RSV for 24 h. A positive cooperative effect of the binding sites for the transcription factors, nuclear factor (NF)-kappa B and NF-IL-6, was observed. Mutations in either region abates responsiveness of the promoter to RSV infection. RSV also increases activation of the NF-kappa B and NF-IL-6 transcription factors. These data suggest that RSV may increase IL-8 production in airway epithelium partly via activation of the transcription factors NF-kappa B and NF-IL-6.

Base Sequence↗
PubMed1996

The carboxyl terminus of the murine MyD116 gene substitutes for the corresponding domain of the gamma(1)34.5 gene of herpes simplex virus to preclude the premature shutoff of total protein synthesis in infected human cells.

The herpes simplex virus 1 mutants from which both copies of the gamma(1)34.5 gene had been deleted trigger total shutoff of protein synthesis in human neuroblastoma cells and human foreskin fibroblasts but not in African green monkey (Vero) cells. The carboxyl-terminal 64 amino acids of gamma(1)34.5 are homologous to the corresponding domain of MyD116, a murine myeloid differentiation primary responsive gene. The carboxyl-terminal domain of gamma(1)34.5 is required to preclude the shutoff of protein synthesis (J. Chou and B. Roizman, Proc. Natl. Acad. Sci. USA 91:5247-5251, 1994). We report that in-frame substitution of the carboxyl terminus of gamma(1)34.5 with the corresponding domain of MyD116 in the context of the viral genome restored the ability of gamma(1)34.5 to preclude premature shutoff of protein synthesis in both neuroblastoma cells and in human foreskin fibroblasts. The results suggest that (i) in the course of its evolution, the virus "borrowed" a gene fragment to preclude a cell response to infection and (ii) the carboxyl terminus of MyD116 and its family of genes known as GADD34 may have a similar function(s) in cells stressed by growth arrest, DNA damage, and differentiation and in herpes simplex virus infection.

Animals↗
PubMed1996

The chemical modification of E. coli L-asparaginase by N,O-carboxymethyl chitosan.

E. coli L-asparaginase was modified with N,O-carboxymethyl chitosan in the presence of normal product L-aspartic acid, which protected the active site of the enzyme. The modified enzyme remained high catalytic activity, showed greater stability against trypsin and alpha-chymotrypsin, but lost its activity more rapidly at high temperature (> 45 degrees C) than did the native enzyme. When tested in vivo, the plasma half-life of the modified enzyme (t1/2 = 40 hr) was over 33 times longer than that of the native enzyme (t1/2 = 1.6 hr). The results showed that the modified L-asparaginase may be much more useful than did the native enzyme for clinical treatments of tumors.

Animals↗
PubMed1996

Gallium-67 scanning for detection of alveolitis in idiopathic pulmonary fibrosis and sarcoidosis.

OBJECTIVE: To investigate 67Gallium scanning for the detection of alveolitis in idiopathic pulmonary fibrosis and sarcoidosis. PATIENTS AND METHODS: 67Ga scintigraphy was performed in 14 patients with IPF (age: mean +/- s = 58.3 +/- 10.3 years), 13 patients with sarcoidosis (age: mean +/- s = 46.9 +/- 9.0 years) and 11 controls (age: mean +/- s = 44.0 +/- 10.5 years). RESULTS: Lung/thigh ratio was respectively 3.18 +/- 0.07 in IPF, 3.12 +/- 0.94 in sarcoidosis and 2.11 +/- 0.26 in controls. IPF and sarcoidosis groups had a significantly higher lung/thigh ratio comparing with the control group (P < 0.05). Three patients received 67Ga scanning examination after corticosteroid therapy and the 67Ga uptake decreased. CONCLUSIONS: The 67Ga scintigraphy is useful in monitoring the activity and extent of alveolitis.

Aged↗
PubMed1996

Expression of TGF-beta 1, PDGF and IGF-1 mRNA in lung of bleomycin-A5-induced pulmonary fibrosis in rats.

OBJECTIVE: To investigate the influence of alveolar macrophages (AMs), fibroblasts and interstitial cells on development of lung fibrosis, and the interactions among TGF-beta 1 PDGF and IGF-1 and these cytokines-effects on lung fibrosis. MATERIAL AND METHODS: Expressions of TGF-beta 1, PDGF and IGF-1 mRNA in the lung cells and lung tissues in different stages of Bleomycin-A5-induced pulmonary fibrosis in rats were studied through Northern hybridization. RESULTS: The expressions of TGF-beta 1 and PDGF mRNA reached their peaks in AMs of pulmonary fibrosis in rats on the 7th day after Bleomycin-A5 instillation. It was similar with that in the lung tissues. IGF-1 mRNA remained relatively stable in AMs during the course. PDGF and IGF-1 mRNA increased gradually in fibroblasts, and reached the highest expressions in the interstitial cells. There was almost no TGF-beta 1 mRNA expression in all groups of fibroblasts. CONCLUSIONS: AMs are the main sources of TGF-beta 1 and PDGF in the lung tissues with fibrosis induced by Bleomycin-A5 AMs are activated in the first weekend and secrete TGF-beta 1 and PDGF to promote fibroblasts proliferation and fibrosis. As fibrosis developed, fibroblasts have established PDGF and IGF-1 autocrine and these three cytokines paracrine nets combined with the interstitial cells to promote lung fibrosis.

Animals↗
PubMed1995

Tumor necrosis factor alpha-308 alleles in multiple sclerosis and optic neuritis.

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, is believed to play an important role in multiple sclerosis (MS) pathogenesis. A bi-allelic polymorphism in the TNF-alpha promoter region (TNF alpha-308), has been reported to influence levels of TNF-alpha production. In the present study, we investigated the TNF alpha-308 polymorphism in 93 patients with MS, 17 patients with optic neuritis (ON) and 95 healthy individuals using an allele-specific PCR technique. Allelic genotype was compared with TNF-alpha mRNA expression levels and HLA class II phenotypes. No significant difference regarding the TNF alpha-308 polymorphism was observed between MS patients and controls. Specifically, the less common allele, TNF2, which is associated with higher expression levels of TNF-alpha, was somewhat less frequent among MS patients. In fact, analysis of 19 patients homozygous for the MS associated HLA-DR-DQ haplotype HLA-Dw2 showed that this haplotype does not carry the TNF2 allele. In addition, in 47 patients, the TNF-alpha alleles did not correlate with expression levels measured as numbers of TNF-alpha expressing cells. Thus, we found no evidence for an important role of TNF alpha-308 polymorphism for genetic susceptibility to MS.

Alleles↗
PubMed1995

Phage RNA polymerase vectors that allow efficient gene expression in both prokaryotic and eukaryotic cells.

We have developed expression vectors that direct the synthesis of proteins from a common set of signals in both prokaryotic and eukaryotic cells. To allow transcription from a common promoter the vectors rely upon a phage RNA polymerase (RNAP). To direct initiation of translation to the same start codon the vectors utilize an internal ribosome entry site (IRES) from encephalomyocarditis virus (EMCV) that has been modified to include a prokaryotic ribosome-binding site (RBS) at an appropriate distance upstream from the desired start codon. These vectors provide levels of expression in eukaryotic cells that exceed those of a conventional RNAP-II-based system by 7-fold, and expression in bacterial cells at levels comparable to other phage RNAP-based systems. Inclusion of a lac repressor and a phage promoter/lac operator fusion element allows tight regulation. Cotransfection of eukaryotic cells with the expression vector and a vector that encodes the phage RNAP provides high-level transient expression without the need to construct specialized stable cell lines.

Alkaline Phosphatase↗
PubMed1995

Preparation of probe-modified RNA with 5-mercapto-UTP for analysis of protein-RNA interactions.

We report a modified synthesis for 5-mercapto-UTP (5-SH-UTP) and its use for analysis of protein-RNA interactions utilizing Escherichia coli and T7 RNA polymerases and yeast RNA polymerases I and III. 5-SH-UTP did not affect transcriptional pausing, Rho-independent termination or recognition of the E. coli transcription complex by NusA. RNA containing 5-SH-UMP did not crosslink to polymerase when irradiation was 302 or 337 nm. Transcription complexes containing RNA substituted with 5-SH-UMP were post-transcriptionally modified to attach a photocross-linking group to thiol-tagged nucleotides in the RNA on the surface of the polymerase of free in solution. The pKa for 5-SH-UTP was determined to be 5.6, so modification of the thiol groups in the RNA with p-azidophenacyl bromide could be carried out at pH 7. Addition of the transcription termination factor Rho, a RNA binding protein, to E. coli transcription complexes resulted in RNA crosslinking to Rho and to the beta and beta' subunits of polymerase. Using 5-SH-UTP, one can distinguish RNA binding domains on the surface of RNA polymerases or other RNA binding proteins from those buried within the protein.

Base Sequence↗
PubMed1995

Increased bile acid concentration in liver tissue with cholesterol gallstone disease.

Patients with cholesterol gallstone disease have a reduced pool of bile acids. Overly sensitive feedback inhibition of bile acid synthesis has been postulated to explain this size reduction. To test this hypothesis, hepatic bile acid concentration and the activity of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme for bile acid biosynthesis, were determined in ten patients with cholesterol gallstones and ten patients without gallstones. The bile acids present in liver tissue are the sum of those returning to liver and those newly synthesized in liver. If an overly sensitive feedback inhibition truly existed in our gallstone patients, a decreased concentration of hepatic bile acids would have been expected. However, patients with cholesterol gallstones had significantly higher total (143.3 +/- 25.5 vs 64.5 +/- 10.8 nmol/g liver, P < 0.01), chenodeoxycholic (64.1 +/- 9.9 vs 29.8 +/- 5.4, P < 0.01), deoxycholic (22.8 +/- 10.9 vs 2.0 +/- 0.7, P < 0.05), and ursodeoxycholic acid (6.2 +/- 1.4 vs 1.5 +/- 0.6, P < 0.01) concentrations than patients without gallstones. The activity of cholesterol 7 alpha-hydroxylase did not differ significantly between the two groups. Impaired hepatic transport or secretion of bile acids is strongly suspected in cholesterol gallstone patients. The findings of the present study showed no evidence of overly sensitive feedback inhibition of bile acid synthesis in cholesterol gallstone patients. Bile acid pool size may be affected by the inappropriate increase of hepatic bile acids rather than by overly sensitive feedback inhibition.

Bile↗
PubMed1995

Inactivation and unfolding of aminoacylase during denaturation in sodium dodecyl sulfate solutions.

During denaturation by sodium dodecyl sulfate (SDS), aminoacylase shows a rapid decrease in activity with increasing concentration of the detergent to reach complete inactivation at 1.0 mM SDS. The denatured minus native-enzyme difference spectrum showed two negative peaks at 287 and 295 nm. With the increase of concentration of SDS, both negative peaks increased in magnitude to reach maximal values at 5.0 mM SDS. The fluorescence emission intensity of the enzyme decreased, whereas there was no red shift of emission maximum in SDS solutions of increasing concentration. In the SDS concentration regions employed in the present study, no marked changes of secondary structure of the enzyme have been observed by following the changes in far-ultraviolet CD spectra. The inactivation of this enzyme has been followed and compared with the unfolding observed during denaturation in SDS solutions. A marked inactivation is already evident at low SDS concentration before significant conformational changes can be detected by ultraviolet absorbance and fluorescence changes. The inactivation rate constants of free enzyme and substrate-enzyme complex were determined by the kinetics method of the substrate reaction in the presence of inactivator previously described by Tsou [Tsou (1988), Adv. Enzymol. Related Areas Mol. Biol. 61, 381-436]. It was found that substrate protects against inactivation and at the same SDS concentrations, the inactivation rate of the free enzyme is much higher than the unfolding rate. The above results show that the active sites of metal enzyme containing Zn2+ are also situated in a limited and flexible region of the enzyme molecule that is more fragile to denaturants than the protein as a whole.

Amidohydrolases↗
PubMed1995

Accumulation of 7 alpha-hydroxycholesterol in liver tissue of patients with cholesterol gallstones.

Patients with cholesterol gallstones have a reduced pool of bile acids. This study was undertaken to clarify the mechanism by which bile acid biosynthesis does not increase to supranormal levels to cause a reexpansion of the pool. We investigated the first two steps of the bile acid biosynthesis pathway by assaying the activities of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme in this pathway, and 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase, and by measuring the concentrations of 7 alpha-hydroxycholesterol and 7 alpha-hydroxy-4-cholesten-3-one in liver specimens from ten patients with cholesterol gallstones and ten gallstone-free controls. In the patients with gallstones, cholesterol 7 alpha-hydroxylase activity, 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity, and hepatic 7 alpha-hydroxy-4-cholesten-3-one concentration did not significantly different from levels in controls, but hepatic 7 alpha-hydroxycholesterol concentration was more than twofold that of controls (12.9 +/- 2.6 vs 5.3 +/- 1.2 nmol/g liver, P < 0.01). The concentration of 7 alpha-hydroxycholesterol positively correlated with the ratio of cholesterol 7 alpha-hydroxylase activity to 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase/isomerase activity (r = 0.93; P < 0.005) in the gallstone-free controls. In contrast, this correlation disappeared in the patients with gallstones. These results suggest a derangement of the normal 7 alpha-hydroxycholesterol metabolism in the patients with gallstones. The reason for the accumulation of 7 alpha-hydroxycholesterol remains unclear; however, it is possible that, in patients with cholesterol gallstone, the accumulated 7 alpha-hydroxycholesterol causes inappropriate suppression of cholesterol 7 alpha-hydroxylase activity by product inhibition.

3-Hydroxysteroid Dehydrogenases↗
PubMed1995

B cell responses to acetylcholine receptor in rats orally tolerized against experimental autoimmune myasthenia gravis.

Oral administration of acetylcholine receptor (AChR) to Lewis rats prior to myasthenogenic immunization with AChR and complete Freund's adjuvant (CFA) results in the prevention of experimental autoimmune myasthenia gravis (EAMG), and decreased serum levels of anti-AChR antibodies. Using an ELISPOT assay, we have now determined numbers of cells in the popliteal, inguinal and mesenteric lymph nodes, spleen and thymus secreting anti-AChR IgG antibodies. Except for mesenteric lymph nodes, a marked diminution of such cells was detected in these lymphoid organs in rats orally tolerized with AChR compared to buffer-fed or vehicle-fed control rats with EAMG. Of note is that, after AChR feeding, the B cell response to AChR in thymus was diminished to the same low level as in CFA-injected, buffer-fed control rats. The relative affinity of serum anti-AChR IgG antibodies measured by KSCN-ELISA was lower in the orally tolerized rats compared to buffer-fed or vehicle-fed rats. The observations showed that oral administration of AChR, besides preventing clinical EAMG, also counteracts the development of AChR-specific B cells, especially those with high affinity antibody production, in most lymphoid organs.

Administration, Oral↗
PubMed1995

Transforming growth factor-beta 1 suppresses autoantigen-induced expression of pro-inflammatory cytokines but not of interleukin-10 in multiple sclerosis and myasthenia gravis.

Multiple sclerosis (MS) is associated with high levels of circulating T lymphocytes that respond to the myelin antigens myelin basic protein (MBP) and proteolipid protein (PLP) by producing various cytokines including interferon-gamma (IFN-gamma) that makes MS worse and transforming growth factor-beta (TGF-beta), an endogenously produced immunosuppressant that might act beneficially. To further define the role of TGF-beta in MS, we examined the effects of recombinant TGF-beta 1 (rTGF-beta 1) on autoantigen-mediated regulation of cytokines in MS and myasthenia gravis (MG). Blood mononuclear cells (MNC) were cultivated with or without rTGF-beta 1, and with or without autoantigen or the recall antigen PPD. MNC expressing cytokine mRNA were detected after in situ hybridization with radiolabeled cDNA oligonucleotide probes. Femtogram concentrations of rTGF-beta 1 suppressed MBP-, PLP- and PPD-induced upregulation of IFN-gamma, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha), TNF-beta and perforin in MS, and acetylcholine receptor (AChR)-induced augmentation of these pro-inflammatory cytokines in MG, but had no effects on autoantigen- or PPD-induced expression of IL-10 or TGF-beta itself. rTGF-beta 1 also suppressed numbers of myelin antigen-reactive IFN-gamma- and IL-4-secreting cells in MS and AChR-reactive IFN-gamma and IL-4 secreting cells in MG. The selective suppressive effects of TGF-beta 1 on autoantigen-induced upregulation of pro-inflammatory cytokines makes TGF-beta 1 attractive as a treatment alternative in MS and MG.

Adult↗
PubMed1995

Suppression of experimental autoimmune myasthenia gravis and experimental allergic encephalomyelitis by oral administration of acetylcholine receptor and myelin basic protein: double tolerance.

Oral administration of acetylcholine receptor (AChR) or myelin basic protein (MBP) to Lewis rat prior to immunization with AChr or MBP and complete Freund's adjuvant (CFA) has previously been shown to prevent or delay the onset of experimental autoimmune myasthenia gravis (EAMG) or experimental allergic encephalomyelitis (EAE), which represent animal models of myasthenia gravis and multiple sclerosis, respectively. Here we show that Lewis rats immunized with AChr+MBP+CFA developed both signs of muscular weakness seen in EAMG and paresis characteristic for EAE. This disease was associated with high levels of anti-AChR and anti-MBP antibody secreting cells and of AChR- and MBP-reactive INF-gamma secreting Th1-like cells in lymph nodes. The diseased rats also showed upregulation of AChR- and MBP-induced mRNA expression of IFN-gamma in lymph node cells. Oral tolerization with AChR and MBP in combination prior to immunization with AChR+MBP+CFA alleviated clinical disease as well as AChR- and MBP-specific B cell node cells. The results implicate that oral tolerization simultaneously to more than one autoimmune disease-related autoantigen is feasible, and that suppression of autoantigen-induced IFN-gamma and augmentation of TGF-beta are pivotal in tolerance induction.

Administration, Oral↗
PubMed1995

Secondary structure of holo- and apo-aminoacylase from prediction, circular dichroism, and FT-Raman spectroscopy.

The secondary structures of native (Holo-) and Zn(2+)-free (Apo-) aminoacylase were examined by circular dichroism (CD) and Fourier transform Raman (FT-Raman) spectroscopic techniques and prediction methods. Quantitative analysis of the conformationally sensitive amide I band indicates that Holo- and Apo-enzyme contain 19.3 and 17.2% helical structure, respectively. Far-UV CD spectra of Holo- and Apo-enzyme show that they contain 20.1 and 17.6% alpha-helix, respectively. Secondary structure prediction of aminoacylase indicates that it contains approximately 20.9% alpha-helical structure including 10 alpha-helix segments. The results show that after removal of Zn2+ in aminoacylase, the extent of ordered structure was decreased markedly. The conformation at or near the active site of aminoacylase may contain more ordered structure and the presence of Zn2+ may help to maintain the catalytically active conformation at the active site.

Amidohydrolases↗