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Biomedical subjects

F Lu

Publications and source records attributed to F Lu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Is the endogenous peroxyl-radical scavenging capacity of plasma protective in systemic inflammatory disorders in humans?

Systemic inflammatory response syndrome (SIRS) in humans is associated with heightened intravascular oxidative stress. The clinical significance of plasma endogenous antioxidative capability in SIRS remains undetermined. Time-sequence changes of plasma total radical-trapping antioxidant parameter (TRAP) and its components were measured in 135 patients with various clinical conditions leading to SIRS. The results were correlated with clinical parameters. Plasma TRAP significantly depressed upon diagnosis of SIRS (SIRS vs. healthy subjects (n = 50), 605.7 +/- 20.4 vs. 803.4 +/- 30.8 microM Trolox equivalent, p <.001). In survivors (n = 86), TRAP declined further during the course of SIRS, followed by a mild recovery at the end of follow-up. General linear mixed model analysis revealed that uric acid, vitamin C, vitamin E and unidentified antioxidants contributed to most of the changes in TRAP (each factor p <.001). In nonsurvivors (n = 49), TRAP increased steadily until death, and the increase was predominantly the result of the increased contribution of bilirubin (p <.01). Higher TRAP levels were not correlated with diminished blood oxidants formation (r = -0.13, p.05), lower intensity of lipid peroxidation (r = 0.261, p <.05) or lesser disease severity of SIRS. The results do not support the hypothesis that the endogenous peroxyl radical scavenging ability of plasma plays a protective role in the course of SIRS.

Aged↗
PubMed2000

Epidemiologic study of type 2 diabetes in Taiwan.

Diabetes mellitus (DM) in adults is a global health problem, although its prevalence varies widely between different populations and the rate has generally increased worldwide. In Taiwan, the mortality rate from DM has almost doubled over the past 10 years. The prevalence of DM in Taiwan was established between 1985 and 1996 and the rates were between 4.9 and 9.2%. The prevalence of impaired glucose tolerance (IGT) was 15.5% (men 15% and women 15.9%). The prevalence of DM and IGT increased significantly with age for both genders. The significant factors associated with newly diagnosed DM were age, BMI, family history of DM, systolic blood pressure (hypertension), physical activity and serum triglyceride levels. The prevalence of large vessel disease (LVD) in DM and non-diabetic subjects were 20.0 and 12.9%, respectively. Among diabetics, 15.8% had ischemic heart disease (IHD), 1.7% leg vessel disease (leg VD), and 2.5% stroke. In non-diabetics, the prevalence of the aforementioned macroangiopathies were 11.5, 0.2 and 1.2%, respectively. The diabetics had a significantly higher prevalence of macrovascular disease than non-diabetic subjects. The most significantly associated with the LVD was serum cholesterol levels. Serum cholesterol and HbA1(c) were significantly associated with the development of IHD. Cigarette smoking and female gender were significantly associated with the leg VD. The prevalence of diabetic retinopathy (DR) was 35.0%. (background DR 30%, preproliferative DR 2.8% and proliferative DR 2.2%, respectively.) The prevalence of DR for previously and newly diagnosed diabetics were 45.2 and 28.3% (men 42.8 vs. 33.3% and women 47.5 vs. 24.8%), respectively. From multiple logistic regression analysis, duration of DM was the most important risk factor related to DR. Diabetic subjects treated with insulin had a higher risk of developing retinopathy than those treated with dietary control. The prevalence of nephropathy and neuropathy were 12.9 and 23.5%, respectively. For those patients with and those without nephropathy and neuropathy, the duration of DM, percentage of insulin treatment, percentage of hypertension, and fasting plasma glucose were significantly different. Diabetic duration, hypertension, insulin treatment and glycemic control consistently correlated with nephropathy and neuropathy. In conclusion, the prevalence of DM in Taiwan was between 4.9 and 9.2%, and the prevalence of IGT was 15.5%. The possible risk factors of newly diagnosed diabetes were age, family history of DM, BMI, SBP (hypertension), physical activity and triglyceride levels. Diabetes in Chinese subjects share many characteristics similar to other Asian populations. The burden imposed by the chronic complications of diabetes is massive. In Taiwan, the mortality rates from DM have increased greatly over the past 10 years. Reduction of the modificable risk factors such as BMI, hypertenion and dyslipidemia, and increase of physical activity and good glycemic control through public health efforts may help to reduce the risk of DM and its chronic complications.

Adult↗
PubMed2000

Is Chlamydia pneumoniae present in brain lesions of patients with multiple sclerosis?

We investigated the presence of Chlamydia pneumoniae in 81 normal and pathological specimens obtained from postmortem brain tissues of patients with multiple sclerosis and with other neurological or nonneurological diseases. The assays used included PCR amplification of all DNA samples in the initial study. Culture and a second PCR amplification of the organism in a subset of 19 brain specimens were also performed in two separate laboratories. All results were negative. Thus, this study on a large number of brain tissues suggests that C. pneumoniae is not involved in inflammatory demyelination.

Brain↗
PubMed2000

Improved PCR-based subtractive hybridization strategy for cloning differentially expressed genes.

An improved PCR-based subtractive hybridization strategy was used to clone apoptosis-related genes induced by all-trans retinoic acid (ATRA) from human promyelocytic leukemia cell line HL-60 cells. The protocol used the cap-finder method, long-distance PCR, streptavidin magnetic bead-mediated subtraction and spin column chromatography. Twenty-seven clones related to apoptosis were identified by reverse dot blot assay. Seventeen were known genes, of which seven have been reported to be apoptosis related. The remaining 10 were unknown genes, five of which were sequenced and named apr-1 to apr-5. apr-1, apr-2, apr-3 and TNF were reidentified by reverse dot blot, and it is suggested that they might be related to apoptosis. The results suggest that this strategy might be efficient for large-scale cloning of differentially expressed genes in target cells.

Apoptosis↗
PubMed2000

[Foundational study of subcritical water chromatography].

AIM: To study the subcritical water chromatographic discipline of compounds with medium and high polarity on the capillary and packed column. METHODS: A packed and capillary subcritical water chromatography-FID detection system was built up. Six alcohols were well separated on a C18 column and the influence of temperature on chromatographic behavior of alcohols with different polarity was studied. The influence of temperature and pressure on chromatographic behavior of benzoic acid and gensenoside Rg1 on a SE-54 capillary column were also studied. RESULTS: Increasing temperature resulted in the decreasing polarity of mobile phase, shortened retention times of components separated, narrowed peak shape and improved tailing as well. CONCLUSION: Temperature programming could be used successfully to separate compounds with various polarity selectively. Thermostable capillary column could enlarge the range of temperature even more.

Chromatography, Liquid↗
PubMed2000

Evidence for voltage-gated potassium channel beta-subunits with oxidoreductase motifs in human and rodent pancreatic beta cells.

Voltage-gated K(+) channel alpha subunits (K(V) alpha) have been previously identified in pancreatic islet beta-cells where it has been suggested they have a role in membrane repolarization and insulin secretion. Here we report the cloning of the three mammalian K(V) beta subunits, including splice variants of these subunits, from both human and rat pancreatic islets and from the rat insulinoma cell line INS-1. Two of the splice variants, K(V) beta1a and K(V) beta3, previously reported to be neuronal tissue specific, are expressed in islets and INS-1 cells. In addition, a splice variant of K(V) beta2 that lacks two potential protein kinase C phosphorylation sites at the amino terminus is present. Immunoblot analysis suggests a high level of K(V) beta2 subunit protein in rat pancreatic islets and immunoprecipitation with anti-K(V) beta2 antibody pulls down a protein from INS-1 cells that reacts with anti-aldose reductase antibody. The K(V) beta subunits, which are attached to the cytoplasmic face of the alpha subunits and are members of the aldose reductase superfamily of NADPH oxidoreductases, may have an as yet undetermined role in the regulation of insulin secretion by the intracellular redox potential. Finally, we suggest that a systematic nomenclature for K(V) beta subunits first proposed by McCormack et al. be adopted for this family of potassium channel subunits as it corresponds with the nomenclature used for their cognate K(V) alpha subunits.

Aldehyde Reductase↗
PubMed2000

Dysregulation of apoptosis: a possible mechanism leading to chronic progressive renal histological changes in lupus nephritis.

OBJECTIVE: To evaluate apoptosis in lupus nephritis and the relationship between the existence of apoptotic cells in renal tissue and histopathological or clinical changes. METHODS: Apoptosis was detected by in situ nick-end labeling techniques (TUNEL) in renal biopsies from 25 patients with type IV lupus nephritis (LN), 12 patients with IgA nephropathy IgAN, 4 patients with idiopathic mesangioproliferative glomerulonephritis (MsPGN) and 3 patients with acute poststreptococcal glomerulonephritis (APGN). Normal renal tissue obtained at nephrectomy for hypernephroma in 4 adults was used as control. Proliferating cells were identified by proliferating cell nuclear antigen (PCNA) in these patients. RESULTS: Compared to other proliferative glomerulonephritis and controls, the patients with lupus nephritis had less apoptotic cells, a higher ratio of PCNA + cells/TdT + cells (P/T) in renal tissues; and their P/T ratio in glomeruli and tubulointerstitium correlated with the chronicity index, r = 0.4983 (P = 0.0132), r = 0.8399 (P < 0.001), r = 0.6614 (P = 0.0033), respectively. P/T ratios in the glomerulus and tubule had a positive correlation with 24-hour urinary protein, r = 0.8554 (P < 0.001) and r = 0.7134 (P = 0.001); and a negative correlation with creatinine clearance (Ccr), r = -0.4880 (P = 0.0133) and r = -0.7229 (P = 0.001), which in tubules positively correlated with serum creatinine (Scr), r = 0.4107 (P = 0.0414). CONCLUSIONS: Apoptosis is reduced in proliferative lupus nephritis. Intense proliferation without a commensurate increase in apoptosis is a possible mechanism that leads to chronic progressive renal histopathological changes.

Adult↗
PubMed2000

[The distrubution of cell cycle on fibrolasts derived from the pathlogical scars and analysis of Fas gene mutations in keloids using polymerse chain Reaction-based single-strand conformation polymorphism].

OBJECTIVE: To explore the concrete mechanism which accounts for the different growth characteristics of normal skins and pathlogical scars and to identify if the mutations of Fas gene exist. METHODS: Six samples of normal skin, hypertrophic scars and keloids were collected. The means of cell culture was used, and only 6 - 10 passages fibroblasts were selected for experiment. The distribution of cell cycle and expression of protein p53 were analysed with flow cytometry, adherant cell analysis and sorting interactive laser coytometry (ACAS 570). Keloids and hypertrophic scar tissue and the peripheral blood of each patient were collected. After DNA was isolated from the samples, we used the single-stranded conformation polymorphism (SSCP) analysis and DNA sequencing to examine the structure of Fas gene. RESULTS: The expression of p53 protein on the fibroblasts derived from normal skin was significantly elevated in comparison to the hypertrophic scars with lowest propagative fibroblasts. A large percent of fibroblasts derived from the peripherial areas of keloids distributed in G(2), S and M periods with low levels of p53 protein. On the other hand, fibroblasts derived from the central areas of keloids distributed mostly in G(0) and G(1) periods with higher expression of p53 protein. Mutation in Fas gene was identified and confirmed in keloid tissue of 20% (2/10) of keloid patient, which may cause loss of function and contribute to the pathogenesis of keloid. A deletion of the nucleotide "A" at the same position was found, which caused a frameshift mutation in exon 9. CONCLUSION: The difference of the distributions of cell cycle and expression of protein p53 may account for the different growth characteristics in pathlogical scar and normal skin. Mutations in Fas gene may lead to abnormal apoptosis of fibroblasts in keloids, and may contribute to the pathogenesis and progression of keloids.

Adult↗
PubMed1999

Myoglobin-containing carbon-paste enzyme microelectrodes for the biosensing of glucose under oxygen-deficit conditions.

The response of first-generation glucose oxidase (GOx) amperometric glucose biosensors is strongly dependent on the concentration of the oxygen cosubstrate. The incorporation of the natural oxygen binder myoglobin into a GOx-containing carbon-paste matrix is shown to satisfy the oxygen demand of the enzymatic reaction and to provide convenient biosensing of glucose in oxygen-free solutions. Such use of myoglobin-containing mineral oil thus offers an attractive alternative to the use of oxygen-rich fluorocarbon pasting liquids. Further improvements are observed upon doping the fluorocarbon oil with myoglobin. Factors affecting the oxygen independence of the new enzyme microelectrodes, including the myoglobin loading or length of the oxygen reservoir, have been optimized. The myoglobin-doped mineral oil or Kel-F-based carbon-paste enzyme microelectrodes display a highly stable glucose response over prolonged (6-7 h) operations in oxygen-free solutions, indicating no depletion of the internal oxygen supply.

Biosensing Techniques↗
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

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↗