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Biomedical subjects

G Lin

Publications and source records attributed to G Lin.

At least 19 recordsLinked to original sources
PubMed2006

The complete mitochondrial genome sequence and characterization of single-nucleotide polymorphisms in the control region of the Asian seabass (Lates calcarifer).

We determined the complete mtDNA nucleotide sequence of Lates calcarifer using the shotgun sequencing method. The mitochondrial DNA (mtDNA) was 16,535 base pairs (bp) in length, and contained 13 protein coding genes, 22 transfer RNAs, 2 ribosomal RNAs, and one major noncoding control region (CR). The CR was unusually short at only 768 bp. A striking feature of the mitochondrial genome was the high G+C content (46.1%), which is among the highest in fish. The gene order was identical to that of a typical vertebrate. Phylogenetic analyses using concatenated amino acid sequences of 12 protein-coding genes of 30 fish species representing 14 suborders clearly showed Lates calcarifer was located in the cluster of fish species from the order Perciformes, supporting the traditional systematic classification. We characterized single-nucleotide polymorphisms (SNPs) in the CR by sequencing the complete CR of 25 individuals obtained from Australia and Singapore. A total of 68 SNPs were detected. Eighteen SNPs were fixed with alternative nucleotides in Australian and Singapore seabass, and these SNPs could be used for differentiating fish from the two countries.

Animals↗
PubMed2006

Probing structure-function relationships of serine hydrolases and proteases with carbamate and thiocarbamate inhibitors.

Benzene-1,3-di-N-n-octylcarbamate (1), benzene-1-hydroxyl-3-N-n-octylcarbamate (2), benzene-1,3-di-N-n-ocztylthiocarbamate (3), and benzene-1-hydroxyl-3-N-n-octylthiocarbamate (4) are synthesized from 1,3-benzene-diol and are characterized as the pseudo-substrate inhibitors of acetylcholinesterase, butyrylcholinesterase, cholesterol esterase, lipase, trypsin, and chymotrypsin. For these six enzyme inhibitions by 1-4, the pKi values are linearly correlated with their log ki values - Brønsted plots. Therefore, 1-4 inhibit these enzymes through a common mechanism. Moreover, both pKi and log ki values for the inhibitions by 1,3, and 4 are linearly correlated with both pKi and log ki values for the inhibitions by 2, respectively. Thus, the pKi values for the inhibitions by 2 are defined as the nucleophilicity constants of these enzymes (nenzyme). The log k2 values for the inhibitions by 1-4 are also linearly correlated with the nenzyme values. Therefore, the nucleophilicity for serine hydrolases and proteases toward 1-4 also applies the Swain-Scott correlations.

Animals↗
PubMed2006

Characterization of two parvalbumin genes and their association with growth traits in Asian seabass (Lates calcarifer).

Parvalbumins are extremely abundant in fish muscle and play an important role in muscle relaxation. In this study, two parvalbumin genes (PVALB1 and PVALB2) were cloned from Asian seabass (Lates calcarifer). The cDNAs for PVALB1 and PVALB2 were 840 and 667 bp respectively. Both genes consisted of five exons and four introns, encoded 109 amino acids, and were of beta lineage. Using real-time polymerase chain reaction, expression of PVALB1 was detected in all 10 tissues tested, with expression in brain, kidney, muscle and small intestine being 15- to 322-fold higher than in the other tissues. Expression of PVALB2 was detected only in muscle, brain and intestine, and was up to 10-fold lower than PVALB1 expression. A (CT)(17) microsatellite in the 3'-untranslated region of PVALB1 and three single nucleotide polymorphisms (SNPs) in the third intron of PVALB2 were identified. The microsatellite in PVALB1 was significantly associated with body weight and body length at 90 days post-hatch (P < 0.01), whereas the SNPs in PVALVB2 were not associated with these traits.

3' Untranslated Regions↗
PubMed2006

Impact of dynamic airflow on human thermal response.

UNLABELLED: Airflow fluctuation is an important factor affecting indoor thermal environments and human thermal response. In this study, dynamic airflows with different fluctuation characteristics were generated by a dynamic air supply terminal. The influence of three different kinds of airflows, constant airflow, simulated natural airflow and sinusoidal airflow, on thermal comfort was studied. Subjective experiments indicated that a dynamic airflow can cause a stronger cold sensation, and that air movement with 1/f fluctuations similar to natural wind is more acceptable than other dynamic airflows in warm environments. Moreover, the impact of draughts in dynamic airflows on human thermal response is different in neutral-warm (30 degrees C) and cool-neutral (26 degrees C) thermal environments. PRACTICAL IMPLICATIONS: By means of a dynamic air supply terminal it is possible to generate artificial airflows that simulate natural wind indoors. This kind of airflow with higher velocity is more comfortable and causes less draught sensation than the constant airflows supplied by conventional fans. While the cooling effect of this airflow is utilized in the built environment, the design temperature of air-conditioning system can be increased and the amount of energy consumption can be reduced dramatically.

Adult↗
PubMed2006

Isolation, characterization, and linkage analyses of 74 novel microsatellites in Barramundi (Lates calcarifer).

Barramundi (Lates calcarifer) is an important marine food fish species in Southeast Asia and Australia. Seventy-four novel microsatellites were isolated from a genomic DNA library enriched for CA repeats and were characterized in 24 unrelated individuals. Among the 74 microsatellites, 71 were polymorphic, with an average allele number of 7.0 +/- 3.6/locus. The average expected heterozygosity of these polymorphic markers was 0.66. Sixty-three of the 71 polymorphic microsatellites conformed to Hardy-Weinberg equilibrium. Linkage analyses were conducted in a reference family, leading to the assignment of 34 novel microsatellites and 16 published markers in 16 linkage groups. The novel microsatellites developed in this study will contribute significantly to the construction of a first-generation linkage map for mapping of quantitative trait loci in Barramundi, and supply a large choice of markers for studies on population genetics, stock management, and pedigree reconstruction.

Animals↗
PubMed2005

Activity of the new quinolone WCK 771 against pneumococci.

The activity of WCK 771, a new experimental quinolone being developed to overcome quinolone resistance in staphylococci, against quinolone-susceptible and -resistant pneumococci was determined. Comparative activities of ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, clinafloxacin, vancomycin, linezolid, amoxycillin, cefuroxime, azithromycin and clarithromycin were determined with MIC and time-kill experiments. Animal experiments were also performed to test the in-vivo anti-pneumococcal activity of WCK 771 compared to levofloxacin. WCK 771 MIC50/90 values for 300 quinolone-susceptible Streptococcus pneumoniae isolates (108 penicillin-susceptible, 92 penicillin-intermediate and 100 penicillin-resistant) were 0.5/0.5 mg/L; the MICs of beta-lactams and macrolides rose with those of penicillin G, and all isolates were susceptible to vancomycin and linezolid. WCK 771 MIC50/90 values for 25 quinolone-resistant pneumococcal isolates were 4/8 mg/L, compared to 0.5/1 mg/L for clinafloxacin, 2/4 mg/L for gatifloxacin and moxifloxacin, 8/16 mg/L for levofloxacin, and 16/>32 mg/L for ciprofloxacin. Time-kill studies showed that WCK 771 was bactericidal against pneumococci after 24 h at 4 x MIC, as were the other quinolones tested. Animal model studies showed that WCK 771 had efficacy comparable to that of levofloxacin, by both the oral and subcutaneous routes, for systemic infection caused by three quinolone-susceptible isolates of pneumococci. Overall, WCK 771 was potent both in vivo and in vitro against quinolone-susceptible, but not quinolone-resistant, S. pneumoniae, regardless of penicillin susceptibility.

Animals↗
PubMed2005

Activity of five quinolones, three macrolides and telithromycin against 12 Haemophilus influenzae strains with different resistance phenotypes.

Gemifloxacin MICs for 12 Haemophilus influenzae strains with different resistance phenotypes were 0.001-0.015 mg/L. Gemifloxacin was bactericidal against all 12 strains after 24 h at 2 x MIC. Ciprofloxacin, levofloxacin, gatifloxacin and moxifloxacin had MICs of 0.008-0.03 mg/L and similar kill kinetics. Macrolides and telithromycin had unimodal MICs (1.0-8.0 mg/L), except for two strains without efflux systems (0.0125-0.5 mg/L) and two with efflux systems and ribosomal protein mutations (> 64.0 mg/L), and were bactericidal against eight to ten strains tested at 2 x MIC after 24 h.

Anti-Bacterial Agents↗
PubMed2004

The stochastic piston problem.

We obtain analytical solutions for the perturbed shock paths induced by time-varying random motions of a piston moving inside an adiabatic tube of constant area. The variance of the shock location grows quadratically with time for early times and switches to linear growth for longer times. The analytical results are confirmed by stochastic numerical simulations, and deviations for large random piston motions are established.

Journal Article↗
PubMed2003

Isolation of two isoforms of phosphodiesterase 5 from rat penis.

Inhibition of cGMP-specific phosphodiesterase type 5 (PDE5) has been shown to improve penile erection in patients with erectile dysfunction. We have reported previously the cloning of three PDE5 isoforms from human penile tissues. Here we report the cloning of two PDE5 isoforms from rat penile tissues. The similarity between rat and human PDE5A1-specific sequences were 68 and 88% at the nucleotide and amino-acid levels, respectively. Like the bovine and canine PDE5A1 sequences, the rat PDE5A1 sequence lacks the polyglutamine tract that appears to be unique to the human PDE5A1 sequence. The similarity between rat and human PDE5A2-specific sequences were 64 and 100% at the nucleotide and amino-acid levels, respectively. The equivalent of human PDE5A3-specific sequence was identified in the rat PDE5A gene; however, repeated efforts to clone the putative rat PDE5A3 isoform were not successful. Expression of PDE5A1 and A2 mRNA in various tissues was examined by Northern blotting and reverse transcription-polymerase chain reaction. Results from the two experimental procedures were largely in good agreement and indicated that PDE5A1 and A2 mRNA were expressed in a tissue-specific manner with PDE5A2 being the dominant isoform. International Journal of Impotence Research (2003) 15, 129-136. doi:10.1038/sj.ijir.3900983

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2003

Neurotrophic effects of vascular endothelial growth factor and neurotrophins on cultured major pelvic ganglia.

OBJECTIVE: To investigate the feasibility of using a ganglial culture system to screen various growth factors as potential therapeutic agents for pelvic nerve injuries. MATERIALS AND METHODS: The major pelvic ganglia (MPG) were isolated from male rats and attached to culture dishes with the aid of Matrigel (Becton Dickinson, Mountain View, CA, USA). Alternatively, the dorso-caudal region (DCR) of MPG, from which the cavernous nerves originate, was dissected and then attached to a Matrigel-coated coverslip. The MPG or DCR was cultured in serum-free medium supplemented with phosphate-buffered saline (PBS, control), 50 ng/mL of vascular endothelial growth factor (VEGF), 20 ng/mL of a neurotrophin (BDNF, NT3, or NT4), or combinations of these growth factors. After 2 days of incubation, the ganglial tissues with their outgrowing nerve fibres were stained for the expression of NADPH-diaphorase, tyrosine hydroxylase (TH) and acetylcholinesterase (AChE). The length and staining intensity of nerve fibres were analysed. RESULTS: The outgrowing fibres were significantly longer in MPG treated with any of the four tested growth factors than in PBS-treated MPG. The combination of VEGF and NT3 induced the best fibre growth. Improvements to the culturing conditions allowed a histological examination of the outgrowing fibres for the expression of nitric oxide synthase (NOS), TH and AChE. VEGF and BDNF were equally capable of inducing NOS- and TH-expressing fibres. BDNF was much weaker than VEGF for inducing AChE-expressing fibres. CONCLUSIONS: This improved culturing system is potentially useful for screening nerve-regenerating factors; VEGF had neurotrophic effects comparable with BDNF, NT3, or NT4.

Animals↗
PubMed2003

Wogonin suppresses cellular proliferation and expression of monocyte chemoattractant protein 1 in Peyronie's plaque-derived cells.

OBJECTIVE: To test the effect of wogonin on cellular proliferation and expression of monocyte chemoattractant protein 1 (MCP-1) in cells derived from normal and diseased tunica albuginea (TA), as related to Peyronie's disease (PD). MATERIALS AND METHODS: Cells with characteristics of fibroblasts were isolated from three tissue sources. Those from the plaque of patients with PD were designated as P cells, those from the adjacent, normal-appearing tissue as C cells, and those from the TA of patients without PD as N cells. These cells were treated with wogonin at doses of 0, 10, 20 and 40 micromol/L for 24 h or treated at a fixed dose of 40 micromol/L for 1, 8 and 24 h. Cell proliferation was assayed with a commercial kit, MCP-1 mRNA expression by reverse transcription-polymerase chain reaction, and secreted MCP-1 by enzyme-linked immunosorbent assay. RESULTS: Wogonin suppressed cell proliferation in a dose-dependent manner; the effect was more pronounced against P cells at 8 and 24 h. Wogonin down-regulated MCP-1 mRNA expression, especially in P cells. Wogonin suppressed the level of secreted MCP-1 by 59-88%. P cells, which secreted far more MCP-1 than N and C cells at 1 h, were suppressed by 88%. C cells were the least suppressed at all three times. CONCLUSIONS: Wogonin suppressed the proliferation, the expression of MCP-1 mRNA, and the expression of secreted MCP-1 in TA-derived cells. In most cases, the effect of wogonin was greatest against cells derived from the plaque. Wogonin appears to be a worthy candidate for preclinical trials in men with PD.

Anti-Inflammatory Agents↗
PubMed2002

Intracavernosal injection of vascular endothelial growth factor induces nitric oxide synthase isoforms.

OBJECTIVE: To identify genes that are affected by vascular endothelial growth factor (VEGF), as an intracavernosal injection with VEGF improved the recovery of erectile function in a rat model of arteriogenic impotence, specifically examining the three nitric oxide synthase (NOS) genes, nNOS, eNOS, and iNOS. MATERIALS AND METHODS: Male rats had their pudendal arteries ligated or underwent a sham operation. They were then treated by an intracavernosal injection with 4 microg of VEGF in phosphate-buffered saline (PBS) or PBS alone. At 6 and 24 h after treatment electrostimulation was applied to the cavernosal nerve and the intracorporal pressure measured. The erectile tissue was then harvested for RNA isolation and cryo-sectioning. The isolated RNA was used for microarray and reverse transcription-polymerase chain reaction (RT-PCR) analyses, and the tissue sections for immunohistochemical analysis. RESULTS: Microarray analysis detected nNOS, eNOS and iNOS at very low expression levels in PBS-treated rats; expression levels were higher for eNOS and iNOS in all VEGF-treated rats. These results were further confirmed by RT-PCR analysis. Immunohistochemical analysis identified the cavernosal endothelium and smooth muscle as the tissue types where eNOS and iNOS were up-regulated, respectively. CONCLUSIONS: This is the first report of the induction of both eNOS and iNOS in the penis after intracavernosal VEGF. These events may help support a significant recovery of erectile function after interrupting the blood supply to the penis.

Animals↗
PubMed2001

[Retrospective analysis of 102 cycles of intracytoplasmic single sperm injection in treating severe male infertility and fertilization failure].

The aim of this study is to retrospectively analyze 102 cycles which received intracytoplasmic single sperm injection (ICSI) in our lab from January 1998 to December 2000. With the improvements of the technique and environment of the microscopic manipulation from February 2000, the survival rate (90.6%). fertilization rate (73.3%) and embryo development rate (97.3%) of the later stage were significantly higher than those of the previous (68.8%, 39.0%, 78.7% respectively). The clinical pregnancy rate reached a higher level (41.3% and 21.4% respectively). The ICSI technique established currently in our lab can effectively treat the severe male infertility and fertilization failure.

Adult↗
PubMed2001

Chromatographic analysis of Fritillaria isosteroidal alkaloids, the active ingredients of Beimu, the antitussive traditional Chinese medicinal herb.

Bulbus Fritillariae derived from plants of various Fritillaria species is the most commonly used antitussive traditional Chinese medicinal herb and is called Beimu. Herbs derived from similar and/or different species of Fritillaria are also used in Japan and Turkey as traditional or folk medicines. Isosteroidal alkaloids are the main bioactive ingredients in Fritillaria species. As the contents and structure types of these bioactive alkaloids vary in different Fritillaria species, quality control of these active principles in herbal Beimu is very important to ensure its safe and effective clinical use. This review describes the development of chromatographic analyses for the simultaneous qualitative and quantitative determination of the main bioactive Fritillaria isosteroidal alkaloids in herbal and biological samples. The recently developed direct HPLC-evaporative light scattering detection method is the most simple, selective and sensitive assay, and is readily used as a suitable quality control method for the analysis of the active principles of herbal Beimu.

Alkaloids↗
PubMed2001

Essential role for Gab2 in the allergic response.

Dos/Gab family scaffolding adapters (Dos, Gab1, Gab2) bind several signal relay molecules, including the protein-tyrosine phosphatase Shp-2 and phosphatidylinositol-3-OH kinase (PI(3)K); they are also implicated in growth factor, cytokine and antigen receptor signal transduction. Mice lacking Gab1 die during embryogenesis and show defective responses to several stimuli. Here we report that Gab2-/- mice are viable and generally healthy; however, the response (for example, degranulation and cytokine gene expression) of Gab2-/- mast cells to stimulation of the high affinity immunoglobulin-epsilon (IgE) receptor Fc(epsilon)RI is defective. Accordingly, allergic reactions such as passive cutaneous and systemic anaphylaxis are markedly impaired in Gab2-/- mice. Biochemical analyses reveal that signalling pathways dependent on PI(3)K, a critical component of Fc(epsilon)RI signalling, are defective in Gab2-/- mast cells. Our data identify Gab2 as the principal activator of PI(3)K in response to Fc(epsilon)RI activation, thereby providing genetic evidence that Dos/Gab family scaffolds regulate the PI(3)K pathway in vivo. Gab2 and/or its associated signalling molecules may be new targets for developing drugs to treat allergy.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Potential new antitumor agents from an innovative combination of demethylcantharidin, a modified traditional Chinese medicine, with a platinum moiety.

A combination of demethylcantharidin, a modified component of a traditional Chinese medicine (TCM), with a platinum moiety has produced a series of TCM-based platinum compounds [Pt(C(8)H(8)O(5))(NH(2)R)(2)] 1-5, which demonstrate selective cytotoxicity toward SK-Hep-1 (human liver) cell line, and circumvention of cross-resistance. The inclusion of demethylcantharidin rendered the compounds highly active as protein phosphatase (PP2A) inhibitors. The new TCM-Pt compounds may possess a novel dual mechanism of antitumor action: inhibition of PP2A and platination of DNA.

Animals↗