Biomedical subjects

Gang Liu

Publications and source records attributed to Gang Liu.

At least 163 records · Page 9Linked to original sources

PubMed2004

Anti-epitope antibody, a novel site-directed antibody against human acetylcholinesterase.

AIM: To construct synthetic antigens using the epitope of human brain acetylcholinesterase (hbAChE) for induction and detection of the specific antibody against the epitope, and to analyse the immunogenicity of the antibody. METHODS: The epitope (RTVLVSMNYR, amino acids 143-152) of hbAChE was chemically synthesized, coupled with the carrier protein keyhole limpet hemocyanin (KLH) to construct an artificial immunogen (KLH-epitope), and injected into rabbits to raise antibody. The epitope conjugated with bovine serum albumin (BSA) was used as the detection antigen. The specificity of the antibody was tested by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The immunoreaction between the anti-recombinant human butyrylcholinesterase (rhBChE) polyclonal antibody and the biotinylated-epitope was examined by indirect ELISA. RESULTS: The erythrocyte AChE, the hbAChE, rhBChE and the BSA-epitope all immunoreacted with the anti-epitope antibody against the epitope (143-152) of hbAChE, whereas the torpedo AChE did not. CONCLUSION: The hbAChE, the human erythrocyte AChE and hBChE share the conservative antigenic epitope RTVLVSMNYR, hence they can all immunoreact with the anti-epitope antibody. Since the epitope of hbAChE is less similar with the aligned amino acid sequences of AChE of Torpedo californica or Torpedo marmorata, there is not any immunoreactivity between them. The R, M, and N residues in the epitope seem to be necessary radicals for the conservation of antigenicity.

Acetylcholinesterase↗

PubMed2004

[The clinic significance of urinary podocytes in patients with focal segmental glomerulosclerosis].

OBJECTIVE: To address the significance of urinary podocytes in the diagnosis of human focal segmental glomerulosclerosis(FSGS). METHODS: Twelve patients with FSGS and 20 patients with minimal change disease (MCD) were diagnosed by routine renal biopsy, and 8 healthy persons as controls. Morning urinary sediments was collected and centrifuged onto glass slides. Urinary podocytes were identified by immunofluorescent staining of podocyte specific protein Podocalyxin(PCX). The state of podocytes in glomeruli was observed using immunofluorescence. RESULTS: Urinary podocytes were found in 8 out of 12 FSGS patients(66.67%), whereas none of 20 patients with MCD and control had podocytes in their urine. FSGS patients with positives urinary podocytes had prominent manifestation of nephropathy syndrome, whereas no nephrotic syndrome in patients with negative urinary podocytes. Focal absence of the expression of PCX, a marker protein of podocytes in glomeruli was found in FSGS patients, and the locations of absence were consistent with the lesions of focal sclerosis in glomeruli. In contrast, PCX was expressed integrally in MCD patients. CONCLUSION: Appearances of podocytes in urine of patients with nephropathy may be used as one of the reliable, convenient and unharmful accessorial methods for distinguished diagnosis of FSGS and MCD.

Adult↗

PubMed2004

The morphological characteristics and expression of cell cycle regulatory proteins in cellular variants of idiopathic focal segmental glomerulosclerosis.

OBJECTIVE: To investigate the morphological characteristics and expression of cell cycle regulatory proteins in cellular variants of idiopathic focal segmental glomerulosclerosis (FSGS). METHODS: Seventeen cases of cellular variants of FSGS were studied by light microscopy, immunofluorescence (IF), and electron microscopy (EM). The immunohistochemistry and immunoelectron microscopy for the detection of cyclins (cyclin D1, cyclin E, cyclin A, cyclin B1) and cyclin dependent kinase inhibitors (CKIs, including p21, p27, p57) were performed in these cases. RESULTS: The hypertrophy and hyperplasia of epithelial cells overlying sclerotic or collapsed glomerular tufts were the prominent characteristics of cellular variants of FSGS; IF showed segmental deposits of IgM; hyperplastic epithelial cells possessed the features of both podocyte and parietal epithelial cells ultrastructurally. Hyperplastic epithelial cells of cellular lesions showed positive staining for cyclin E, cyclin A, cyclin B1 and p21, and negative staining for cyclin D1, p27 and p57. CONCLUSION: The hyperplastic epithelial cells in cellular variants of FSGS may be derived from damaged podocytes, which mimic the immature podocytes, re-engage the cell cycle to proliferate and form the cellular lesions. The up-regulation of cyclins (cyclin E, cyclin A, cyclin B1) concurrent with the loss of CKIs (p27, p57) contributes to the cell cycle regulation of cellular lesions of FSGS.

Adolescent↗

PubMed2004

[An analysis of the clinical and pathological manifestations of adult idiopathic focal segmental glomerulosclerosis].

OBJECTIVE: To investigate the relative frequency of idiopathic focal segmental glomerulosclerosis (FSGS) in renal biopsy-proven diseases, and its criteria and significance of clinicopathological diagnosis. METHODS: We reviewed all the inpatients that were diagnosed by renal biopsies from 1990 to 2001, of whom 65 were identified as idiopathic FSGS. Their histological characteristics were analyzed together with their clinical findings. RESULTS: (1) The incidence of idiopathic FSGS accounted for 2.2% of all the renal biopsies, 3.2% of primary glomerular diseases, and 5.8% of patients with massive proteinuria. (2) The subtypes of idiopathic FSGS were hilar lesion (12.3%), peripheral lesion (23.1%), mixture lesion (60.0%), collapsing lesion (3.1%), and tip lesion (1.5%), which were frequently accompanied by other morphologic variants, such as synechia of Bowman's capsule, podocyte hyperplasia and hypertrophy, segmental endothelial and mesangial proliferation, and interstitial fibrosis, etc. As the sclerotic lesions distributed segmentally and overlapped by other variants, it was difficult to get the correct diagnosis. (3) Most of the patients with segmental endothelial and mesangial proliferation had massive proteinuria. CONCLUSION: Idiopathic FSGS was not a common glomerular disease in our study. Podocyte lesion, segmental endothelial and mesangial proliferation may play an important role in the formation of segmental sclerosis in idiopathic FSGS.

Adult↗

PubMed2004

[Changes of serum total PSA and free PSA in patients with prostate carcinoma and benign prostate hyperplasia].

BACKGROUND & OBJECTIVE: Total prostate-specific antigen (TPSA) is considered the best marker in diagnosis of carcinoma of prostate (Pca), and FPSA (free prostate specific antigen)/TPSA can improve its specificity in diagnosis of PCa. This study was designed to compare the level of serum TPSA and FPSA/TPSA between PCa and benign prostate hyperplasia (BPH) patients, providing reference for diagnosis of PCa. METHODS: Values of serum TPSA and FPSA of 66 BPH cases, 29 BPH with acute urinary retention (AUR) cases, 22 PCa cases were determined by enzyme linked immunosorbent assay (ELISA). The differences of serum TPSA and FPSA/TPSA of the three groups were compared and analyzed. RESULTS: There were significant differences of serum TPSA concentration among the three groups (P< 0.05), when the serum TPSA in the patients with BPH, BPH and AUR, PCa were 4.1+/-1.39 microg/L, 15.5+/-3.34 microg/L, 55+/-13.5 microg/L, respectively. Serum TPSA concentration overlapped in the three groups especially in AUR group when the TPSA level in the three groups were less than 4.0 microg/L, 4.0-10.0 microg/L, and more than 10.0 microg/L. There was no significant difference between BPH group and AUR group when the FPSA/ TPSA of BPH group was 0.32+/-0.13, AUR group was 0.30+/-0.09 (P >0.05). However, there were significant differences between BPH and Pca group, between AUR and PCa group when the FPSA/TPSA of Pca group was 0.11+/-0.05 (P< 0.05). FPSA/TPSA level also overlapped in these three groups when FPSA/TPSA level was less than 0.15, 0.15-0.25, and more than 0.25. CONCLUSIONS: The serum TPSA and the level of FPSA/TPSA overlapped in these three groups. They can only be regarded clinically as reference index.

Acute Disease↗

PubMed2004

[Study on the relationship between hepatitis C virus infection and sharing injection equipment, sexual behavior among injecting drug users].

OBJECTIVE: To study hepatitis C virus (HCV) transmission through different modes of sharing injection equipment and sexual behavior among injecting drug users (IDUs) in Liangshan of Sichuan province. METHODS: A community-based survey was conducted to investigate past and current demographic data, injection equipment sharing patterns and sexual behavior of IDUs. Blood samples were also taken to test for HCV. The survey was conducted between Nov 8 and Nov 29, 2002. 379 subjects were screened through outreach recruitment and peer informing. SPSS (11.5) was used for data analysis. RESULTS: HCV prevalence was 71.0% (269/379). Needles or syringes sharing in the past three months and past syphilis infection were strongly associated with HCV transmission after univariate analysis using chi-square test. Trend analysis indicated that HCV infection rate increased along with the increase of needles or syringes sharing, sharing of rinse water and the number of peers sharing the equipments. Data from multivariate logistic regression showed that sharing of needles or syringes and history of syphilis infection were significantly associated with HCV transmission. No significant difference was found between HCV infection and sexual behavior after univariate analysis using chi-square test. CONCLUSION: Further sero-epidemiological prospective cohort studies should be conducted to clarify the relationship between different modes of sharing injection equipment, sexual behavior and HCV infection.

Adult↗

PubMed2004

Technology evaluation: ISIS-113715, Isis.

Isis is developing ISIS-113715, an antisense inhibitor of the PTP1B gene, for the potential treatment of type 2 diabetes and obesity. ISIS-113715 is undergoing phase II clinical trials.

Animals↗

PubMed2004

[Application of M-RAPD technique to obtain the genomic fingerprints of various pathogenic microbials].

OBJECTIVE: To obtain genomic fingerprints of different pathogenic microbials and make certain whether their patterns can be used in the identification of microbials by means of multiplex random amplified polymorphic DNA analysis (M-RAPD). METHODS: Arbitrary primers of 10 oligonucleotides were randomly grouped, and various microbials chromosomal DNA were amplified with three combinatorial primers at a special higher annealing temperature. The products were detected by 15 g/L agarose electrophoresis and the patterns were analyzed by the software of Gelworks 1d Intermediate. RESULTS: Specific and resistant DNA fingerprints for different pathogenic microbials with combinatorial primers were gained. The profiles were clear, well-distributed and the number was great. The products of the three primers included most products of every two primers and would appear with no relation to their length, but small products had more opportunity; three primers could provide information contents half as many again as that two primers could provide for the same pathogenic microbials. There were obvious differences among different drug-resistant strains and between the drug-resistant strains and the corresponding reference strains, but different strains of the same microorganism had more similarity than discrepancy. The analytic data of the software of Gelworks 1d Intermediate also support our results. CONCLUSION: M-RAPD is a simple and rapid technique for the identification of different kinds of pathogenic microbials, and it can provide rich genetic information.

DNA Fingerprinting↗

PubMed2004

[Studies on the change of intercellular connection and the appearance and function of ectodesmata-like structure in garlic clove during the dormancy development].

The characteristics of intercellular connection have been observed during the dormancy development of garlic by the transmission electron microscope (TEM). The results indicated that the appearances of the different states of intercellular connection were physiological adaptation to the development of garlic clove during storage. Ectodesmata-like existed at the wall boundary between the declining tissue and the living cells in the garlic during germination period. By Confocal Laser Scanning Microscopy (CLSM) combined with fluorescence probe, 457Da Lucifer Yellow (LYCH) which was impermeable to the membrane, could enter the living parenchyma cell through symplastic route. The result proved that ectodesmata-like structure, which may be recognized as the modified plasmodesata, still retained physiological activity during a certain time and function as the channels of the symplastic transport of nutrient.

Garlic↗

PubMed2004

[Molecular cloning and expression analysis of a novel human testis-specific gene].

Digital Differential Display (DDD) of the National Center for Biotechnology Information (NCBI) is a quantitative method that enables the user to determine the fold differences between the libraries being compaired, using a statistical method to quantitate the transcript levels. In this study, DDD program was performed between nine testis libraries ('tester') and seventy-six libraries derived from other tissues ('driver'). We identified a new contig of expression sequence tags (ESTs) HS. 129794 which were from testis libraries. To validate the use of bioinformatics approaches in gene discovery, the ESTs HS. 129794, which was predicted to be testis -specific, was chosen for further study. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis of mRNA from different normal tissues indicated that HS. 129794 was specifically expressed in human testis. By querying EST and Unigene datagases, a full-length cDNA sequence of novel gene in human were identified, it was 2 430 bp in length, located in chromosome 3p21.1. The sequence of the open reading frame was 676 approximately 1 248 bp, as was confirmed by RT-PCR and sequencing in human testis. The cDNA encodes a novel protein of 190 amino acids with a theoretical molecular weight of 20 417.8 and isoelectric point of 5.23. The sequence shares no significant homology with any known protein in databases. Semi-quantitative RT-PCR analysis of multiple tissues further showed that the novel gene is expressed significantly in different stage of human testis and sperm. We hypothensize that its functions as a testis-specific and spermatogenesis related gene that plays some roles in spermatogenesis, and named it SRG5 (Testis Spermatogenesis Related Gene 5, SRG5) (GeneBank accession number: AY221117). Identification of SRG5 using DDD approaches validates gene discovery using computational approaches.

Amino Acid Sequence↗

PubMed2004

[Cloning of cDNA of SRG4, a mouse spermatogenesis related gene and expression in mouse different developing stages].

Spermatogenesis required lots of genes taking part in this process. In prevision studies, Odf1, Odf2, Sak57, Spag4, Spag5 were identified in mouse and rat sperm tail developing. Two ESTs, BG101130 and BG100990, which coded amino acid sequences with high homology to rat Spag4, were found from mouse spermatocytes. By electrical hybridization, a 1 155 bp sequence was obtained and named as SRG4 (Spermatogenesis Related Gene 4) (GenBank accession number: AY307077), which included the full-length sequence of mouse testis hypothetical gene AK006225. The opening reading frame of SRG4 was 87 approximately 1 133 bp, and was proved by RT-PCR in mouse testis. The information analysis showed SRG4 gene was located in 2H1-H2, and the putative protein was 348-amino acid with a coiled-coil region, suggesting SRG4 might function as a transmembrane protein. The homologies of amino acid sequences were 74% between TSARG4 and SRG4 gene and 45% between SRG4 and rat Spag4 gene, respectively. RT-PCR and Northern blot results showed SRG4 gene expressed specifically in mouse testis. Changes of SRG4 expression in mouse different developing stages were observed. The results showed SRG4 gene expressed slightly in two weeks postpartum, and expressed abundantly from three weeks, and reached the top at 4 -5 weeks. This indicted SRG4 gene may play an important role in mouse spermatogenesis.

Amino Acid Sequence↗

PubMed2004

Effect of type I collagen on the adhesion, proliferation, and osteoblastic gene expression of bone marrow-derived mesenchymal stem cells.

OBJECTIVE: To investigate the effects of porous poly lactide-co-glycolide (PLGA) modified by type I collagen on the adhesion, proliferation, and differentiation of rabbit marrow-derived mesenchymal stem cells (MSCs). METHODS: The third generation MSCs isolated from mature rabbits by density gradient centrifugation were cultured at different initial concentrations on 0.3 cm x 1.2 cm x 2.0 cm 3-D porous PLGA coated by type I collagen in RPMI 1640 containing 10% fetal calf serum, while cultured on PLGA without type I collagen as control. The cells adhesive and proliferative behavior at 7, 14, and 21 days after inoculation was assessed by determining the incorporation rate of [(3)H]-TdR. In order to examine MSCs differentiation, the expression of osteoblasts marker genes, osteocalcin (OCN), alkaline phosphatase (ALP), osteopontin (OPN) mRNA, were evaluated by reverse transcription-polymerase chain reaction (RT-PCR), and further more, the cell morphology at 21 days was also observed by scanning electron microscope (SEM). RESULTS: Type I collagen promoted cell adhesion on PLGA. The valve was significantly higher than controls (6 h, 2144 cpm+/-141 cpm vs. 1797 cpm+/-118 cpm, P=0.017; 8 h, 2311 cpm+/-113 cpm vs. 1891 cpm+/-103 cpm, P=0.01). The cells which cultured on PLGA coated with type I collagen showed significantly higher cell proliferation than controls on the 7 th day (1021 cpm+/-159 cpm vs. 451 cpm+/-67 cpm, P=0.002), the 14th day (1472 cpm+/-82 cpm vs. 583 cpm+/-67 cpm, P<0.001) and 21 th day (1728 cpm+/-78 cpm vs. 632 cpm+/-55 cpm, P<0.001). Osteoblasts markers, OCN, ALP, OPN mRNA, were all detected on PLGA coated by type I collagen on the 21 th day, but OCN, OPN mRNA could not be found in controls. Spindle and polygonal cells well distributed on the polymer coated by type I collagen while cylindric or round cells in controls. CONCLUSIONS: Type I collagen is effective in promoting the adhesion, proliferation and differentiation of MSCs on PLGA.

Biocompatible Materials↗

PubMed2004

[Identification of gastrodia elata blume by Fourier transform infrared spectroscopy].

In this paper, a method of rapid and undamaged identification of wild and cultivated Gastrodia elata Blume, and one of its fakes by Fourier transform infrared spectroscopy (FTIR) is reported. The results show that Gastrodia elata Blume and its fake have different characteristic infrared spectra, by which Gastrodia elata Blume can be identified from its fake. Wild winter, wild spring, and cultivated Gastrodia elata Blume can be discriminated by FTIR, according to the differences of their spectral peaks and absorbance ratios. By the differences of absorbance ratios of several peaks, different grade of Gastrodia elata Blume may be classified. FTIR has proved to be a rapid, simple and nondestructive method for the identification of Gastrodia elata Blume.

DNA, Plant↗

PubMed2004

[Identification of edible mushrooms by Fourier transform infrared spectroscopy].

In this paper, Fourier transform infrared spectroscopy (FTIR) was used to identify edible mushrooms belonging to Auriculariales, Aphyllophorales, and Agaricales of Basidiomycotina. Vibrational spectra of fruiting bodies of ten species belonging to nine different genera of mushrooms (one is cultivated, and the others are wild growing) were recorded. The spectra were divided into five regions, i.e. 3 050 to 2 800 cm(-1), 1 750 to 1 500 cm(-1), 1 500 to 1 200 cm(-1), 1 200 to 950 cm(-1), and 950 to 700 cm(-1). These regions contain characteristic bands among different mushrooms. According to the characteristic bands in the five regions, different species of mushrooms can be identified. Vibrational spectra in the interval between 950 and 700 cm(-1) could serve as fingerprints to discriminate different genera of mushrooms.

Agaricales↗

PubMed2004

[Clinical value of PET/CT for the diagnosis and management of lung nodules].

OBJECTIVE: To investigate the clinical value of 18F-fluorodeoxyglucose positron emission tomography (FDG PET)/CT for the diagnosis and management of lung nodules. METHODS: Twenty patients were evaluated: 15 with suspected cancer and 5 confirmed cancer. PET/CT scans were performed by discovery LS-PET/CT system. RESULTS: (1) The diagnostic accuracy of PET/CT was 100% in these 20 patients. Of 15 patients with suspected cancer, 7 were diagnosed as having benign disease and 8 malignant. All the 5 patients with confirmed cancer were all FDG positive. Of 11 single lesions on CT, 3 were positive by PET/CT images, 6 of 8 with positive CT images were diagnosed as having metastasis to the tissue outside the lung and the other 2 were metastatic. (2) After PET/CT scanning, the therapy scheme of 16 out of 20 patients were changed, and continual observation was practiced in 2, 3 were treated by anti-inflammation regimen, 2 by operation, 4 by local radiotherapy, 3 by chemotherapy only, 4 by radiotherapy plus chemotherapy or operation. (3) The radiotherapists made use of PET/CT fusion imaging for positioning in 8 patients who were indicated for radiotherapy. One of them who had received MM50 one course of intensity medulated conformal radiotherapy was re-examined by PET/CT after one and half months, the former parenchymal nodule disappeared and the glucose metabolism returned to normal. Two of them were finally operated after the surgeons have decided an operative approach on estimation of extent of lesion by the PET/CT fusion images. Pathological results showed no cancer cell involvement in the specimen margin or the local lymph nodes. CONCLUSION: (1) PET/CT is better in discriminating malignant from benign lung nodules than CT only. (2) PET/CT scanning facilitates an accurate assessment of response in clinical staging and neoadjuvant therapy scheme of lung cancer. (3) PET/CT fusion imaging provides an accurate biological target for radiotherapy and confirms the operation plan and extent of surgery.

Adult↗

PubMed2004

[FTIR study on the finger nail with carcinoma of nasopharynx].

Finger nails from twenty normal people and three with carcinoma of nasopharynx were studied by Fourier Transform Infrared (FTIR) technique. The results showed that there are obvious differences between FTIR spectra of them in spectral parameters such as frequency, intensity and band shape etc. The most striking differences in the spectra were observed in the change of amide II, the disappearance of delta(s) (CH3) peak, and at 874.0 cm(-1) whether appeared an absorption peak. The changes involving the phosphate symmetric stretching nu(s, PO2-) and asynmmetric stretching nu(as, PO2-) modes, the CH3 and CH2 groups stretching (v(s, CH2), nu(as, CH3)) bending (delta (CH3)) modes and the C-O stretching nu (C-O) mode were discussed. In addition, the changes of structure of hydrogen-bonding of nucleic acid and cell proteins and the packing and the conformational structure of the membrane lipids were analysed. The average wave number of band of nu(s) (PO2-) shifted from 1080.0 to 1077.6 cm(-1) and that of nu(as) (PO2-) shifted from 1239.4 to 1238.4 cm(-1), which indicated that the degree of hydrogen-bonding formed by oxygen atom of the phosphodiester groups of nucleic acids was weakened. The average wave number of band of delta (CH2) of membrane lipids shifted from 1453.1 to 1453.7 cm(-1), and its peak intensity was slightly enhanced, which suggested that the conformational structure of the methylene chains of membrane lipids is more disordered than in normal nail.

Carcinoma↗

PubMed2003

In vivo temporal and spatial distribution of depolarization and repolarization and the illusive murine T wave.

This study assessed in vivo temporal and spatial electrophysiological properties of murine hearts and the effect of manipulation of transmural action potential durations (APDs) on T wave morphology. Monophasic action potentials (MAPs) were acquired from multiple left ventricular sites. All MAPs exhibited a plateau phase, with a spike and dome appearance being present in epicardial recordings. Activation occurred from endocardial apex to epicardial apex and apex to base while repolarization occurred from base (shortest 90 eta0 level of repolarization (MAP90), 95.4 +/- 8.9 ms) to apex and epicardium to endocardium (longest MAP90, 110.77 +/- 10.6 ms). The peak of phase 0 of the epicardial base MAP correlated with the return to baseline of the initial and usually dominant waveform of the QRS and the onset of the second usually smaller wave, which clearly occurred in early repolarization, thus establishing where depolarization ended and repolarization began on the murine ECG. This second waveform was similar to the J wave seen in larger animals. Despite temporal and spatial electrophysiological similarities, a T wave is frequently not seen on a murine ECG. There are several determinants of T wave morphology, including transmural activation time, slope of phase 3 repolarization and differences in epicardial, endocardial and M cell APDs. Experimental manipulation of murine transmural gradients by shortening epicardial MAP(90) to 84% of endocardial MAP90 the epicardial/endocardial ratio in larger mammals when a positive T wave is present, resulted in a positive murine T wave. Thus, manipulation of the transmural gradients such that they are similar to larger mammals can result in T waves with similar morphology.

Action Potentials↗

PubMed2003

Optical feedback laser with a quartz crystal plate in the external cavity.

We studied the optical feedback characteristics of a single-mode He-Ne laser with a quartz crystal plate in the external cavity. The fringe frequency of the laser system can be doubled when the quartz crystal plate is positioned at a certain angle between the crystalline axis and the beam in the crystal plate. Theoretical analysis shows that the birefringent effect of the quartz crystal plate and the laser beam's second pass through the external cavity result in this phenomenon. The experimental results are in good agreement with the theoretical analysis. A quartz crystal plate can double the resolution of a self-mixing sensing system.

Journal Article↗