Biomedical subjects

G Luo

Publications and source records attributed to G Luo.

At least 19 recordsLinked to original sources

PubMed2006

Short-term administration of ACTH improves plasma lipid profile and renal function in kidney transplant patients.

The present study investigated effects of short-term administration of adrenocorticotrophic hormone (ACTH) on blood lipid profile and renal function in kidney transplant patients. Six patients who had kidney transplantations 2 to 10 years earlier received ACTH intramuscularly (1 mg/d) for 4 days. We analyzed serum levels of lipids, lipoproteins, apolipoproteins, blood creatinine, and other parameters. Short-term ACTH treatment significantly decreased serum apolipoprotein B and apolipoprotein AI, whereas it significantly increased plasma high-density lipoproteins (HDL). Interestingly, creatinine level moderately decreased and creatinine clearances moderately increased among five of six patients. Hepatic function and serum concentration of cyclosporine did not change. There were no serious side effects during ACTH treatment. It was concluded that ACTH treatment had beneficial effects on serum lipoprotein profile, potentially improving renal function in kidney transplant patients. Further observations are needed to confirm these effects.

Adrenocorticotropic Hormone↗

PubMed2006

Effects of ischemia-reperfusion injury on apolipoprotein M expression in the liver.

The present study investigated the expression pattern of apolipoprotein M (apoM) mRNA in a rat model of hepatic ischemia-reperfusion injury (IRI). Animals were ischemic for 1 hour followed by various reperfusion times. As expected, serum alanine aminotransferase levels were significantly increased under IRI, which indicated the severity of liver injury. Hepatic mRNA levels of HSP70, which is the most common characterized protein within the family of heat-shock proteins (HSP), were significantly increased after 0.5 to 3 hours of IRI. Plasma C-reactive protein, high-density lipoprotein-cholesterol, and lipoprotein (a) levels were significantly increased after 1-hour ischemia followed by 0.5 to 3 hours of reperfusion. Interestingly, similar to HSP70, apoM mRNA levels in the liver were gradually increased after 0.5 to 3 hours of IRI, whereas it returned to a lower level after 6 or 24 hours of IRI, which indicated that hepatic apoM expression was significantly influenced by the acute phase of IRI. However, plasma apoM levels were not increased in parallel, even slightly decreasing after 0.5 or 1 hour of IRI. We concluded that apoM mRNA expression pattern, like HSP70, in the liver showed rapid, significant changes during hepatic local IRI.

Animals↗

PubMed2006

Relationship between PTEN gene expression and differentiation of human glioma.

OBJECTIVE: To investigate the relationship between PTEN gene expression and differentiation of glioma. MATERIAL AND METHODS: The quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) method was applied to detect PTEN mRNA levels in glioma tissues. Tumor-adjacent normal tissues and benign brain tumors were used as controls. Relative PTEN mRNA levels were determined as the ratio of PTEN and GAPDH, which were correlated with the clinical-pathological results. RESULTS: PTEN mRNA levels were significantly lower in the glioma tissues than in the benign brain tumors and tumor-adjacent normal tissues, whereas there were no statistical differences between benign brain tumor and the tumor-adjacent normal tissues. According to the pathological examinations, PTEN mRNA levels were higher in the high differential glioma than the low differential glioma. CONCLUSIONS: PTEN gene expression was suppressed in the glioma, which is related to the clinical-pathological results. It is suggested that determination of PTEN mRNA levels by RT-PCR could be a novel marker of disease classification.

Adolescent↗

PubMed2006

Metformin-diet ameliorates coronary heart disease risk factors and facilitates resumption of regular menses in adolescents with polycystic ovary syndrome.

BACKGROUND: In 35 adolescent females (17 +/- 2 years) with polycystic ovary syndrome (PCOS), median body mass index (BMI) 30.8 kg/m2, we assessed effeicacy of metformin-diet for 1 year for reduction of weight, insulin, HOMA insulin resistance (IR), cholesterol, triglycerides, and resumption of regular menses. METHODS: Calories (26% protein, 44% carbohydrate) were targeted to 1,500-1,800/day if BMI was <25 or to 1,200-1,500/day if BMI was > or = 25, along with 2,550 mg metformin. RESULTS: Median weight fell from 82.7 to 79.1 kg (p = 0.009), insulin 16.7 to 13.3 microU/ml (p <0.0001), HOMA IR 3.41 to 2.74 (p = 0.0004), total cholesterol 164 to 151 mg/dl (p = 0.002), and triglyceride 103 to 85 mg/dl (p = 0.006). The percentage of cycles with normal menses rose from a pre-treatment mean of 22% to 74%, p < 0.0001. CONCLUSIONS: In adolescents with PCOS, metformin-diet reduces weight, insulin, IR, cholesterol, and triglycerides, and facilitates resumption of regular menses.

Adolescent↗

PubMed2005

Desorption/ionization on silicon nanowires.

Dense arrays of single-crystal silicon nanowires (SiNWs) have been used as a platform for laser desorption/ionization mass spectrometry of small molecules, peptides, protein digests, and endogenous and xenobiotic metabolites in biofluids. Sensitivity down to the attomole level has been achieved on the nanowire surfaces by optimizing laser energy, surface chemistry, nanowire diameter, length, and growth orientation. An interesting feature of the nanowire surface is that it requires lower laser energy as compared to porous silicon and MALDI to desorb/ionize small molecules, therefore reducing background ion interference. Taking advantage of their high surface area and fluid wicking capabilities, SiNWs were used to perform chromatographic separation followed by mass analysis of the separated molecules providing a unique platform that can integrate separation and mass spectrometric detection on a single surface.

Chromatography↗

PubMed2004

Prospective study of relationship between cytomegalovirus pneumonia and viral load in renal transplant recipients.

The present study prospectively examined the relationship between cytomegalovirus interstitial pneumonia (CMV-IP) and viral load among 56 renal transplant recipients. We sought to identify the cutoff of viral load to predict CMV-IP. Blood samples were obtained weekly within the first 2 months and every second week during 2 to 6 months after kidney transplantations. A commercial real-time polymerase chain reaction (PCR)-method was applied to quantify CMV-DNA in plasma or in leukocytes. Among 54 renal transplant recipients who were analyzed for CMV-DNA in the blood (96.4%), 8 experienced CMV-IP (14.3%) and 2 died (3.6%). After kidney transplantation, CMV-DNA loads were near 0 in plasma before the week 4 and before the week 3 in leukocytes among both groups. From week 5 (week 4, in leukocytes), plasma CMV-DNA loads in the CMV-IP group increased, the peak value reached at week 8 in plasma and the week 9 in leukocytes. Whereas, the CMV-DNA loads both in plasma and in leukocytes in the non-CMV-IP group fluctuated at lower levels, those in plasma were significantly different between the 2 groups at the weeks 5, 7, and 9. For CMV-DNA in leukocytes, there were significant differences between 2 groups from week 6 to week 11. The present study demonstrated that dynamic determination of CMV-DNA may predict the occurrence of CMV-IP. Viral loads over 10(4) copies/mL plasma continuing for 3 weeks may serve as a cutoff to predict CMV-IP.

Cytomegalovirus↗

PubMed2004

Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion.

The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

Aerosols↗

PubMed2003

Development of novel oligonucleotide probes for seven Actinomyces species and their utility in supragingival plaque analysis.

OBJECTIVE: The traditional, biochemical and enzymatic methods of identifying Actinomyces species are frequently confounded by the similar phenotypic characteristics shared by the different members of this genus. Therefore, we developed novel species-specific oligonucleotide probes to accurately speciate seven pathogenic Actinomyces species, namely, Actinomyces bovis, A. gerencseriae, A. israelii, A. meyeri, A. naeslundii, A. odontolyticus and A. viscosus. METHODS: A pair of universal primers and seven 15- to 19-base oligonucleotide probes with a tail of 20 thymidines on the 5' end were developed. The variable regions of 16S ribosomal DNA of 36 strains of Actinomyces belonging to the above species were amplified and labeled with digoxigenin, and an oligonucleotide-DNA hybridization assay was performed to examine the specificity and sensitivity of these probes. RESULTS: All seven, newly developed probes were specific and sensitive, and accurately detected 36 reference and wild type strains belonging to Actinomyces species, without cross-reactions. The probe for A. naeslundii detected all strains belonging to the genospecies 1 (12 strains) and catalase-negative genospecies 2 (four strains); it failed to detect catalase-positive A. naeslundii genospecies 2 (previous A. viscosus serotype II) (two strains). However, the latter strains of catalase-positive A. naeslundii genospecies 2 were correctly detected by the probe developed for A. viscosus. The new probes were then field tested using supragingival plaque samples from 28 healthy preschool children. Whilst A. odontolyticus was detected in almost all samples (96.4%), A. gerencseriae, A. meyeri, catalase-negative A. naeslundii and catalase-positive A. naeslundii genospecies 2 were detected in < 50% samples. CONCLUSION: We conclude that the developed oligonucleotide probes, complementary to the variable regions of 16S rDNA, would be of potential value for differentiating Actinomyces spp. in clinical samples from the oral cavity and other ecosystems where such species may abound.

5' Flanking Region↗

PubMed2002

Candida glabrata, an emerging fungal pathogen, exhibits superior relative cell surface hydrophobicity and adhesion to denture acrylic surfaces compared with Candida albicans.

Oral candidosis is a common opportunistic infection in debilitated individuals and Candida glabrata is the second most frequently isolated species from this condition, after Candida albicans. Candidal adherence to various biological or non-biological surfaces is considered a prerequisite for colonization, and pathogenesis of candidal infections, and their relative cell surface hydrophobicity (CSH) is likely to be a possible contributory force involved in this process. Whereas a large body of data on the latter features of C. albicans is available, there is surprisingly little information on C. glabrata. As a comprehensive database on the relative adhesion and CSH of Candida spp. is instructive and useful, we investigated in vitro the latter attributes of 34 oral isolates of C. glabrata and 15 isolates of C albicans. There were remarkable intraspecies differences in both the CSH and the adhesive ability of C. glabrata strains (p < 0.001). Compared with C. albicans, C glabrata demonstrated a four-fold greater CSH value (30.63 +/- 11.20% vs 7.23+/-3.56%, p < 0.0001) and a two-fold greater tendency to adhere to denture acrylic surfaces (75.18 +/- 39.96 vs 30.36+/-9.21, p < 0.0001). A significant positive correlation between CSH and adhesion was also noted for both C. glabrata (r=0.674, p < 0.0001) and C. albicans ( r = 0.636, p < 0.05). When the effect of different incubation conditions on the relative CSH and adherence of C. glabrata was examined, CSH and the adherence to acrylic surfaces of four of six C. glabrata isolates were significantly affected by a reduction of the culture temperature (from 37 degrees C to 25 degrees C). A positive relationship also emerged when the temperature-induced variations in the adherence values were correlated with their relative CSH. These data provide hitherto unavailable archival information on important pathogenic attributes of the two most common oral Candida species that may help explain their predominance in this milieu.

Acrylic Resins↗

PubMed2001

Generation of three selenium-containing catalytic antibodies with high catalytic efficiency using a novel hapten design method.

A novel strategy for design of haptens that were used to produce catalytic antibodies was developed and three monoclonal antibodies, 3G5, 2F3, and 5C9, were generated using this strategy. These monoclonal antibodies were converted into selenium-containing abzymes by chemically modifying the hydroxyl group of serines followed by sodium hydrogen selenide displacement. These selenium-containing abzymes exhibited remarkable glutathione peroxidase activity, which surpasses the activity of some native glutathione peroxidases. The activities of the selenium-containing abzymes Se-3G5, Se-2F3, and Se-5C9 which catalyzed reduction of hydroperoxides by glutathione were 2.23, 4.20, and 3.79 times that of rabbit liver glutathione peroxidase, respectively. Detailed steady-state kinetics study on Se-2F3 was carried out and the value of k(cat)/K(m) (H(2)O(2)) was found to be 2.11 x 10(7) M(-1) min(-1) which was supposed to be one of the highest among the known catalytic antibodies. The data of association constants and glutathione peroxidase activities of these catalytic antibodies and the steady-state kinetics of Se-2F3 showed that the method might be a remarkably efficient one for generating catalytic antibodies with glutathione peroxidase activity.

Amino Acid Sequence↗

PubMed2001

A novel dicyclodextrinyl ditelluride compound with antioxidant activity.

Reactive oxygen species (ROS) primarily arise from products of normal metabolic activities and are thought to be the etiology of many diseases. A novel dicyclodextrinyl ditelluride (2-TeCD) compound was designed to be a functional mimic of the glutathione peroxidase that normally removes ROS. 2-TeCD exhibited highly catalytic efficiency and good water solubility. Antioxidant activity was studied by using ferrous sulfate/ascorbate-induced mitochondria damage model system. 2-TeCD protected the mitochondria against oxidative damage in a dose-dependent manner and exhibited also great antioxidant ability in comparison with 2-phenyl-1,2-benziososelenazol-3(2H)-one. The mimic may result in better clinical therapies for the treatment of ROS-mediated diseases.

Animals↗

PubMed2001

Cloning and expression of a single-chain catalytic antibody that acts as a glutathione peroxidase mimic with high catalytic efficiency.

Glutathione peroxidase (GPX) has a powerful role in scavenging reactive oxygen species. In previous papers we have developed a new strategy for generating abzymes: the monoclonal antibody with a substrate-binding site is first prepared, then a catalytic group is incorporated into the monoclonal antibody's binding site by using chemical mutation [Luo, Zhu, Ding, Gao, Sun, Liu, Yang and Shen (1994) Biochem. Biophys. Res. Commun. 198, 1240-1247; Ding, Liu, Zhu, Luo, Zhao and Ni (1998) Biochem. J. 332, 251-255]. Since then we have established a series of catalytic antibodies capable of catalysing the decomposition of hydroperoxides by GSH. The monoclonal antibody 2F3 was raised against GSH-S-2,4-dinitrophenyl t-butyl ester and exhibited high catalytic efficiency, exceeding that of rabbit liver GPX, after chemical mutation. To produce pharmaceutical proteins and to study the reason why it exhibits high catalytic efficiency, we sequenced, cloned and expressed the variable regions of 2F3 antibody as a single-chain Fv fragment (2F3-scFv) in different bacterial strains. The amounts of 2F3-scFv proteins expressed from JM109 (DE3), BL21 (DE3), and BL21 (coden plus) were 5-10%, 15-20% and 25-30% of total bacterial proteins respectively. The 2F3-scFv was expressed as inclusion bodies, purified in the presence of 8 M urea by Co(2+)-immobilized metal-affinity chromatography (IMAC) and renatured to the active form in vitro by gel filtration. The binding constants of the active 2F3-scFv for GSH and GSSG were 2.46 x 10(5) M(-1) and 1.03 x 10(5) M(-1) respectively, which were less by one order of magnitude than that of the intact 2F3 antibody. The active 2F3-scFv was converted into selenium-containing 2F3-scFv (Se-2F3-scFv) by chemical modification of the reactive serine; the GPX activity of the Se-2F3-scFv was 3394 units/micromol, which approaches the activity of rabbit liver GPX.

Amino Acid Sequence↗

PubMed2001

Identification and determination of glucuronides and their aglycones in Erigeron breviscapus by liquid chromatography-tandem mass spectrometry.

A novel, speedy and reliable LC-MS-MS method for the search, identification and quantitation of O-glycosides and their aglycones from plant resources was established by analyzing the extract of Erigeron breviscapus. The extract was directly infused to a triple-quadrupole MS-MS and major glucuronides in the extract were screened out with high confidence by a neutral loss scan for the loss of a gluconic acid. The identity of these glucuronides and their aglycones was further confirmed with LC-MS-MS. In addition to scutellarin, apigenin 7-O-glucuronide, quercetin-3-O-glucuronide and their aglycones that were previously reported by others, we also confirmed by LC-MS-MS that remarkable amount of baicalin, an isomer of apigenin 7-O-glucuronide, presented in the extract of this plant, which had not been reported before. A satisfying quantitation of three glucuronides was also made by LC-MS-MS.

Asteraceae↗

PubMed2001

An approach to the identification of potent inhibitors of influenza virus fusion using parallel synthesis methodology.

Structure-activity studies associated with the salicylic acid-derived inhibitor of influenza fusion, BMY-27709, were examined using a parallel synthesis approach. This SAR survey led to the discovery of potent influenza inhibitory activity in a series of aromatic amides and thioamides derived from 1,3,3-trimethyl-5-hydroxycyclohexylmethylamine. Select compounds were characterized as inhibitors of the H1 subtype of influenza A viruses that act by preventing the pH-induced fusion process, thereby blocking viral entry into host cells. In a plaque-reduction assay, the most potent inhibitors displayed EC(50) values of 0.02-0.14 microg/mL.

Amines↗

PubMed2001

Kinetics study of a selenium-containing ScFv catalytic antibody that mimics glutathione peroxidase.

The steady-state kinetics study and some enzymatic characterization of a selenium-containing scFv catalytic antibody (Se-scFv2F3) were carried out. A novel reaction formula of this abzyme-catalyzed reaction was proposed and a rate equation was obtained according to the formula. The constants in the equation were compared with Dalziel's parameters and the exact meanings of these constants were analyzed. The obtained kinetics parameters from the kinetics study of Se-scFv2F3 were analyzed and compared with those of native glutathione peroxidase.

Antibodies, Catalytic↗

PubMed2001

Kinetics study of a selenium-containing ScFv catalytic antibody that mimics glutathione peroxidase.

The steady state kinetic study and some enzymic characterization of a selenium-containing scFv catalytic antibody (Se-scFv2F3) was carried out. A novel reaction formula of this abzyme-catalyzed reaction was proposed and a rate equation was gotten according to the formula. The constants in the equation were compared with Dalziel's parameters and the exact meanings of these constants were analyzed. The gotten kinetics parameters from the kinetics study of Se-scFv2F3 were analyzed and compared with that of native glutathione peroxidase.

Antibodies, Catalytic↗

PubMed2001

Determination of scutellarin in Erigeron breviscapus extract by liquid chromatography-tandem mass spectrometry.

A quantitative assay for scutellarin by LC-MS-MS (negative ion mode) was developed. The scutellarin was extracted from dry Erigeron breviscapus. Significant ion suppression was observed, which could be eliminated by increasing the turboionspray interface temperature to 350 degrees C and by 1000-fold dilution of the extract with solvent. The calibration curve of scutellarin showed excellent linearity over a wide concentration range (0.01-100 microg/ml) (r=0.998), and the limit of detection was 15 pg/ml using a 10-microl injection volume. The analysis time was 4 min/sample.

Asteraceae↗

PubMed2001

A novel glutathione peroxidase mimic with antioxidant activity.

Many diseases are associated with the overproduction of hydroperoxides that inflict cell damage. A novel cyclodextrin derivative, 6A,6B-diseleninic acid-6A',6B'-selenium bridged beta-cyclodextrin (6-diSeCD), was synthesized to be a functional mimic of glutathione peroxidase (GPX) that normally removes these hydroperoxides. The mimic had high catalytic GPX activity of 13.5 U/micromol, which is 13.6-fold higher than ebselen (PZ51), and was chemically and biologically stable in vitro. Antioxidant activity was studied by ferrous sulfate/ascorbate-induced mitochondria damage model system. These data show that the mimic has great antioxidant activity. Such mimics may result in better clinical therapies for diseases mediated by hydroperoxides.

Animals↗