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Biomedical subjects

F Lu

Publications and source records attributed to F Lu.

At least 73 records · Page 4Linked to original sources
PubMed1999

Autoreactive IgG to intracellular proteins in sera of MS patients.

IgG binding to multiple protein constituents in lysates of Jurkat cells was detected by Western blot in sera of patients with multiple sclerosis (MS) and systemic lupus erythematosus (SLE). The distribution patterns of bands with sera tested against protein lysates from normal Jurkat cells or from Jurkat cells exposed to apoptosis or oxidative stress inducing conditions were similar in most patients, but with inter-individual differences. The number of bands with sera of both patient populations far exceeded those (0 or 2 bands) detected with sera of healthy controls. Proteinase K, RNase and DNase pre-treatment of cell lysates suggested a protein nature for all of the antigens and a ribonucleoprotein (RNP) nature for some of the antigens recognized by serum IgG of MS and SLE patients. Only two MS patients had positive anti-nuclear antibody (ANA) titers, while all of them had positive Western blots. In addition to similarities, dissimilarities were also recognized between the humoral immune responses in MS and SLE. No IgG molecules were detected against phosphorylated proteins in the sera of MS patients, while multiple phosphoproteins were recognized by IgG molecules of SLE patients in immunoprecipitation experiments. These data suggest that in addition to ANA, the sera of MS patients contain autoantibodies directed against multiple intracellular proteins. The protein recognition patterns of immunoglobulins in MS share similarities, but also have distinct features when compared to those in SLE. The biological significance of these autoantibodies in MS remains to be understood.

Antibodies, Antinuclear↗
PubMed1999

Arylpropane-1,3-diols in lignins from normal and CAD-deficient pines.

Significant quantities of arylopropane-1,3-diols have been identified in lignins isolated from a CAD-deficient pine mutant; smaller amounts are also present in lignins from normal pine. They arise from dihydroconiferyl alcohol via the action of peroxidases which are responsible for the radical generation steps of lignification. The structures in the complex lignin polymers are proven using 2D and 3D NMR of isolated lignin fractions.

Alcohol Oxidoreductases↗
PubMed1999

Activation of gonadotropin-releasing hormone receptors produces neuronal excitation in the rat hippocampus.

Whole-cell patch-clamp recordings of evoked action potentials were made in CA1 and CA3 pyramidal neurons of rat hippocampal slices. Previously we have demonstrated that activation of gonadotropin-releasing hormone (GnRH) receptors induces a long-lasting enhancement of synaptic transmission mediated by ionotropic glutamate receptors in CA1 pyramidal neurons of rat hippocampal slices. Here, we further studied whether activation of GnRH receptors could modulate intrinsic neuronal excitability in CA1 and CA3 pyramidal neurons of rat hippocampal slices. The use of a specific GnRH analog, leuprolide (10(-8) M), elicited a relatively long-term increase in evoked action potentials in CA1 and CA3 pyramidal neurons, respectively. The GnRH receptor-induced increase in evoked action potentials in both CA1 and CA3 pyramidal neurons could be abolished by a potent GnRH receptor antagonist, [acetyl-3,4-dehydro-Pro1,D-p-F-Phe2,D-Trp(3,6)]-LHRH (10(-8) M). The present study suggests that activation of GnRH receptors can lead to an increase of intrinsic neuronal excitability of both CA1 and CA3 pyramidal neurons in the rat hippocampus, an important integrative region for reproductive process, both endocrinologically and behaviorally.

Action Potentials↗
PubMed1999

[Right bundle branch block, ST segment elevation and sudden cardiac death. A clinical and electrocardiographic syndrome--Brugada syndrome].

The association of an abnormal electrocardiogram (ecg) consisting of right bundle branch block and ST segment elevation in leads V1-V3 and sudden arrhythmic death has been described in patients with no demonstrable structural heart disease. A patient with these ecg findings and aborted sudden death is presented. The patient had no structural heart disease and received an implantable cardioverter-defibrillator which seems to be the treatment of choice.

Adult↗
PubMed1999

Activation of gonadotropin-releasing hormone receptors induces a long-term enhancement of excitatory postsynaptic currents mediated by ionotropic glutamate receptors in the rat hippocampus.

Whole-cell patch-clamp recordings were made from CA1 pyramidal neurons of the rat hippocampus to study the modulation of gonadotropin-releasing hormone (GnRH) on synaptic transmission mediated by ionotropic glutamate receptors. Leuprolide (10(-9)-10(-7) M), a specific GnRH analog, concentration-dependently elicited a long-lasting potentiation of excitatory postsynaptic currents (EPSCs) mediated by ionotropic glutamate receptors. GnRH receptor-induced synaptic potentiation was blocked by 1 microM [Acetyl-3,4-dehydro-Pro1,D-p-F-Phe2,D-Trp3,6]-LHRH, a specific GnRH receptor antagonist. Furthermore, GnRH receptor-induced synaptic potentiation was associated with the stimulation of protein kinase C (PKC), being considerably attenuated by a potent PKC inhibitor (30 microM H-7). The results suggest a long-term enhanced modulation of GnRH on synaptic transmission mediated by ionotropic glutamate receptors, possibly via the actions of PKC in the hippocampus that is an important integrative system in the regulation of reproductive processes.

Animals↗
PubMed1999

Effect of Sinomenine on IL-8, IL-6, IL-2 produced by peripheral blood mononuclear cells.

The effect of Sinomenine on IL-8, IL-6, IL-2 and mIL-2R produced by peripheral blood mononuclear cells was investigated by using cell culture, radioimmunoassay and flow cytometry. It was showed that production of IL-8 and mIL-2R was inhibited, but the levels of IL-6 were enhanced by Sinomenine. Our results also demonstrated that Sinomenine did not have any effect on the production of IL-2. The study demonstrated that Sinomenine was able to regulate the production of cytokines. This may be one of the mechanisms by which Sinomenine works on rheumatoid arthritis.

Antirheumatic Agents↗
PubMed1999

The DFRC method for lignin analysis. 7. Behavior of cinnamyl end groups.

The behavior of cinnamyl end groups of lignins during the derivatization followed by reductive cleavage (DFRC) procedure has been investigated using lignin model compounds. On AcBr treatment, hydroxycinnamyl alcohols give rise mainly to 1-aryl-1, 3-dibromopropanes from which 1-aryl-3-bromopropanes and arylcyclopropanes are formed by zinc reduction. Arylpropene derivatives are also significant among DFRC products of etherified cinnamyl end-group models. Major monomers from DFRC of hydroxycinnamaldehydes are arylcyclopropyl acetates produced by reductive ring closure of 1-acetoxy-3-aryl-1,3-dibromopropanes. Although the reactions are not as clean as the ether-cleaving reactions that form the basis of the DFRC method, end groups produce diagnostic compounds that provide valuable markers for studying end groups in lignins.

Alcohols↗
PubMed1999

Detection and determination of p-coumaroylated units in lignins.

The derivatization followed by reductive cleavage (DFRC) method cleaves alpha- and beta-ethers in lignins but leaves lignin gamma-esters intact. When applied to grasses, which contain p-coumarate esters on their lignins, esterified monolignol derivatives are released. Saturation of the p-coumarate double bond occurs during DFRC, so the released products are 4-acetoxycinnamyl 4-acetoxyphenylpropionates. Synthesis of the esters allowed determination of response factors for the released products. Maize and bamboo lignins released 221 and 38 micromol/g of p-coumarate-derived esters. The sinapyl ester was much more abundant than the coniferyl one. The bamboo and maize lignin S/G ratios in the conjugates were 12 and 38 times greater than those of the normal monomers released by DFRC, evidence of a strong selectivity for acylation of syringyl units. Of three possible biochemical mechanisms for incorporating p-coumarates into lignin, evidence is mounting that the process involves incorporation of preacylated monolignols into the normal lignification process.

Chemistry, Organic↗
PubMed1999

Are lignins optically active?

The accepted derivation of lignins from non(enzymatically)-controlled radical coupling reactions has been recently challenged, and it is relevant to ascertain unequivocally whether lignins are or are not (as normally assumed) optically active. Two approaches were used. First, DFRC (derivatization followed by reductive cleavage) dimers derived from beta-5- and beta-beta-units in pine lignins, which certainly retain unaltered chiral centers (as well as beta-1- and beta-O-4-units where the intactness may be debated), were shown to be optically inactive by circular dichroism (CD) and chiral high-performance liquid chromatography. CD of beta-5-derived dimers following enantiomeric separation readily demonstrated the sensitivity of the method. Second, no optical activity could be detected (above 250 nm to avoid carbohydrate contributions) by CD of lignin isolates from pine, kenaf, maize, or a CAD-deficient pine mutant. Representative lignins are therefore not, within limits of detection by these methods, optically active.

Carbohydrate Conformation↗
PubMed1999

A dominant-negative mutant of c-Jun inhibits cell cycle progression during the transition of CD4(-)CD8(-) to CD4(+)CD8(+) thymocytes.

While Jun/Fos-containing transcription factors are known to be necessary for many TCR-mediated events in mature T cells, relatively little is known about their roles in thymocyte development. We have generated transgenic mice that express a trans-dominant-negative mutant of c-Jun (TAM-67) specifically in thymocytes. Expression of TAM-67 inhibited the up-regulation of AP-1-responsive genes such as c-jun and IL-2 in stimulated thymocytes from transgenic mice. In addition, altered thymocyte development in TAM-67-expressing mice was revealed by a decrease in thymic cellularity ( approximately 50%) which could be accounted for primarily by a reduction in the number of CD4(+)CD8(+) thymocytes, a large percentage of which retained CD25. The decrease in the number of CD4(+)CD8(+) thymocytes did not appear to be due to an enhanced rate of apoptosis but rather to a decrease in the number of CD4(-)CD8(-)CD25(-) cells in the S + G(2)/M stages of the cell cycle. These results indicate that Jun/Fos-containing transcription factors promote the proliferative burst that accompanies the transition from the CD4(-)CD8(-) to the CD4(+)CD8(+) stage of thymocyte development.

Animals↗
PubMed1999

Tracking RPE transplants labeled by retroviral gene transfer with green fluorescent protein.

PURPOSE: To determine whether human retinal pigment epithelium (RPE) can be modified by retroviral-mediated gene transfer and to monitor the human RPE cells in the subretinal space of living rabbits with scanning laser ophthalmoscopy (SLO). METHODS: Cultured human fetal retinal pigment epithelium (HFRPE) was exposed to green fluorescent protein (GFP)-transducing retroviral vectors, Moloney murine leukemia virus, and lentivirus. The cultured cells were followed by fluorescence microscopy. Suspensions of GFP-expressing HFRPE were transplanted into the subretinal space of pigmented rabbits, and the transplant sites were examined by SLO for fluorescence, including fluorescein and indocyanine green angiography. The rabbits were euthanatized at different times after transplantation, and the retinas were studied histologically. RESULTS: Retroviral gene transfer can introduce a foreign gene such as GFP into cultured HFRPE. Gene expression is maintained in cultured RPE for at least 3 months. The lentiviral vector transduced both nondividing and dividing cells; the Moloney vector only transduced the latter. GFP-expressing cells can be followed in the living retina. Their changes reflect the rejection response followed histologically. CONCLUSIONS: Cultured HFRPE could be transduced to express GFP for long periods of time by retroviral gene transfer. GFP allowed retinal transplants and gene expression to be monitored in vivo. These results provide a model for potential ex vivo gene therapy in the subretinal space.

Animals↗
PubMed1999

[Quality evaluation of locally-prepared kits for HIV antibody detection in clinical applications].

OBJECTIVE: To evaluate the quality of eight kinds of locally prepared enzyme-linked immunosorbent assay (ELISA) kits for HIV antibody (anti-HIV) detection and study their current status in clinical applications. METHODS: Two hundred serum specimens were tested with eight kinds of locally prepared ELISA kits for anti-HIV screening, with an imported kit as reference, including 100 specimens with confirmed positive, negative or undetermined anti-HIV and 100 specimens collected from the drug abusers in Xinjiang Region. RESULTS: Anti-HIV could be detected in all the 74 confirmed positive specimens with the imported reference kit, with sensitivity of 100%. But, six to eighteen specimens were false negative detected with local prepared kits, with sensitivities of 81.1%-91.9%, mainly in those collected from the drug abusers with weak positive for anti-HIV. Two of the 107 confirmed negative specimens were false positive by the imported reference kit, with a specificity of 98.2%, and 0-8 specimens were false positive by locally prepared kits, with specificities of 92.5%-100%. CONCLUSION: The sensitivity of locally prepared ELISA kits for anti-HIV screening should be improved further to ensure the safety of blood transfusion and the control of AIDS/HIV.

China↗
PubMed1999

[The changes of plasma endothelin-1 and calcitonin gene-related peptide levels in patients with pregnancy induced hypertension].

OBJECTIVE: To study the changes and clinical significance of plasma endothelin (ET-1) and calcitonin gene-related peptide (CGRP) levels in patients with pregnancy induced hypertension (PIH). METHODS: Plasma ET-1 and CGRP were studied by immunoradiological method in 60 patients with pregnancy induced hypertension (PIH) and 23 normal pregnant women and 20 normal non-pregnant women. RESULTS: The levels of plasma ET-1 in patients with PIH were significantly higher than those in healthy pregnancies (P < 0.01). There was a positive correlation between the plasma ET-1 level and degree of PIH; the higher the ET-1 level, the severer the PIH. The levels of plasma CGRP in patients with moderate and severe PIH decreased significantly than those in healthy pregnancy. There was a negative correlation between the plasma CGRP level and ET-1 level. CONCLUSION: The results suggest that plasma ET-1 and CGRP concentration could be used as indicators for the severity of PIH. CGRP may be one of the antagonists of ET-1 in the pathogenesis of PIH.

Adult↗
PubMed1999

[Mortality of primary liver cancer in China from 1990 through 1992].

OBJECTIVE: To study the geographical distribution and mortality of primary liver cancer (PLC) in China from 1990 through 1992. METHODS: A death survey among one tenth of Chinese population was conducted in 1990-1992 and the data on PLC mortality were analyzed. RESULTS: The crude mortality for PLC was 20.4 per 100,000 population (29.0 per 100,000 for males and 11.2 per 100,000 for females), accounted for 18.8% of the total cancer deaths in 1990-1992. In China, PLC mortality ranked second after stomach cancer. The age-standardized mortality rate (adjusted by the world population) of male Chinese was 33.7 per 100,000 which was 2. 2 times as high as that of male Japanese and 4.6 times as high as that of male Italian. The age-standardized rate of female Chinese was 12.3 per 100,000 which was 3.1 and 5.1 times as high compared to female Japanese and female Italian, respectively. PLC occurred in every age group but the mortality rate was highest in the age group of 30-44 years. The mortality was slightly higher in the rural than in the urban population. The cumulative death rate in the urban population was 3.5% for males and 1.2% for females, while that in the rural population was 4.1% for males and 1.6% for females. PLC showed geographical clustering along the south-east coast of China. CONCLUSION: To prevent primary liver cancer remains to be the major task of cancer control in China.

Adolescent↗
PubMed1999

[Effects of humic acid on lipid peroxidation in arsenosis prevalent areas].

OBJECTIVE: To explore the causes of blackfoot disease in Taiwan. METHODS: Experiments to induce lipid peroxidation by arsenic and humic acid were made in vitro. Arsenic was determined for the water sampled from the arsenosis prevalent areas in Inner Mongolia and blackfoot disease prevalent areas in Taiwan and humic acid determined for the extracts of the coal rich in arsenic sampled from Guizhou Province in China by MDA-TBA colorimetry. RESULTS: Experiments found that humic acid could induce lipid peroxidation caused by sodium salt of unsaturated fatty acids in vitro in a weak and unstable manner, which could be promoted by 0.05 mmol/L of Fe(+ +) and not by 1 mmol/L As(2)O(3). The extent of lipid peroxidation caused depended on the sources, constituents and structure of humic acid samples, those from Inner Mongolia ranked the highest, those from Guizhou and Taiwan the medium and the commercial humic acid (Aldrich Co. in the US) the lowest. The experiments also found that lipid peroxidation caused by commercial humic acid presented a dynamic process in the existence of trace amount of iron, and humic acid could decompose the products of lipid peroxidation. CONCLUSION: The experiments suggested the relations of humic acid and arsenic to iron and other transition elements in the blackfoot disease prevalent areas and areas with an environment rich in arsenic and humic acid.

Arsenic Poisoning↗
PubMed1999

[Relationship of nitric oxide and immunal function of the patients with acute hepatitis and hepatic cirrhosis].

The interleukin-12(IL-12), interleukin-10(IL-10), tumor necrosis factor(TNF) and nitric oxide (NO) levels in serum of 90 patients with hepatitis and cirrhosis were measured by the method of ELISA and colorimeter. The levels of IL-12, IL-10 and NO in serum of the patients with hepatitis were in close proximity to the level of healthy control, but the TNF level was significantly higher than that of healthy control. The IL-12, IL-10, TNF and NO levels in serum of the patients of hepatic cirrhosis were significantly higher than that of healthy control and patients with hepatitis. The results suggested that the NO level was not related with the hepatic damage of acute hepatitis. The dysfunction of immunology in the patients with cirrhosis was related with the increase of NO level.

Adult↗
PubMed1999

[Study on regulators of the cell cycle in cutaneous squamous cell carcinoma].

In order to investigate the relationship between the regulators of cell cycle and cutaneous squamous cell carcinoma(SCC), we used an immunohistochemical staining technique to examine the expression of cyclin D1, p16 and Rb in the paraffin embedded skin cancer tissues of 30 patients with SCC. The positive percentage of cyclin D1, CDK4, p16 and Rb was 66.7%, 53.3%, 33.3%, and 36.7%, respectively. The overexpression of cyclin D1 and CDK4 could be observed frequently in low grade of differentiated cells, especially in marginal cells of the cancer nest. The results indicate that the aberrant expression of positive and negative regulators of the cell cycle may be involved in the carcinogenesis and evolution of SCC.

Carcinoma, Squamous Cell↗