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Biomedical subjects

Li Lin

Publications and source records attributed to Li Lin.

At least 55 records · Page 3Linked to original sources
PubMed2005

[The effect of fibula flap graft on the restoration of the extremities with traumatic compound tissue defects].

OBJECTIVE: To evaluate the clinical effects of fibula flap grafts on the repair of the extremities with traumatic compound tissue defects. METHODS: In 12 cases, the fibula flap grafts were employed to restore the extremities with traumatic compound tissue defects. Of the 12 patients, 9 were males, 3 were females; their ages ranged from 12 to 45. There were 2 cases of tibia defect combined with fibula fracture, 2 cases of tibia defect, 2 cases of radius defect, 3 cases of ulna defect, 1 case of calcaneus defect, and 2 cases of first-metatarsus defect. The bone defect length ranged from 4.2 to 10.6 cm, 7.8 cm in average. The skin defect area ranged from 10.0 cm x 4.5 cm to 27.0 cm x 15.0 cm. The free transplantation of fibular flaps were used in 9 cases, the lapse operation were used in 2 cases, retrograde shift were used in 1 case. RESULTS: Post-operational vein crisis and common peroneal nerve traction injury were observed in category mentioned above respectively. All the 12 fibula flaps survived after proper treatments such as removal of great saphenous vein. Follow-ups were done for 6 to 24 months. Both the transferred fibula and the recipient broken end reflected bones were healed. Four patients underwent the second-phase reconstruction operation of tendon moving power. One wrist and 1 ankle underwent arthrodesis in 3 to 6 months. All the effects were satisfactory. CONCLUSION: The fibula flap grafts provide a relatively better alternative to repair the extremities with long bone compound tissue defects. In addition, the sensory function reconstruction of fibula flaps should be given full attention.

Adolescent↗
PubMed2005

[Effect of captopril on the nervous function in rabbits exposed to vibration].

OBJECTIVE: To study the effect of captopril on the nervous function in rabbits exposed to vibration. METHODS: Rabbits were divided into vibration group, intervention group, and control group. Vibration group and intervention group were exposed to (tested by) vibration. Captopril was given to intervention group from the 11th day of vibration exposure. Somatosensory evoked potential (SEP) and motor nervous conduction function (MCF) were measured and analyzed in each group before and after vibration exposure. RESULTS: The latent periods of N1, P1 and N2 of SEP in vibration group after vibration exposure were (30.76 +/- 4.26), (41.91 +/- 6.67), and (45.29 +/- 5.81) ms respectively, and in intervention group after vibration exposure were (27.00 +/- 3.04), (35.07 +/- 4.20) and (41.15 +/- 3.19) ms respectively. Compared with intervention group before and after exposure, and control group, the latent periods of each wave of SEP were delayed significantly (P < 0.05). The nervous conduction velocity, the distant wave amplitude, and the distant potential period of sciatic nerve in vibration group after vibration exposure were significantly different from those in intervention group [(35.69 +/- 4.37) m/s, (1.55 +/- 0.73) microV, (8.16 +/- 0.71) ms respectively vs (52.20 +/- 5.13) m/s, (2.89 +/- 0.36) microV, (7.26 +/- 0.77) ms respectively (P < 0.01)]. CONCLUSION: Captopril may improve the impairment of nervous functions to a certain degree in rabbits exposed to vibration.

Animals↗
PubMed2005

[Study on heavy metals in growing area soils and young fruit of Citrus grandis 'Tomentosa'].

OBJECTIVE: To determine the status of heavy metals contamination in growing area soils and young fruits of Citrus grandis. METHOD: Application of Nemerow's index for heavy metals assessment of soil and young fruit of Citrus grandis, as well as according to national environmental quality standard for soils and green trade standards of importing & exporting medicinal plants & preparations. RESULT: The heavy metals content of most of the growing area soils of Citrus grandis rates as first, and of the rest ones rates as second. The heavy metals content in young fruits of Citrus grandis is within the limitation of quantity of criteria. CONCLUSION: The environmental quality of growing area soils of Citrus grandis in Huazhou City is totally in good.

Arsenic↗
PubMed2005

[Detection of porphyromonas gingivalis in buccal epithelial cells and subgingival plaque].

OBJECTIVE: To detect Porphyromonas gingivalis (P. gingivalis) in buccal epithelial cells and subgingival plaque from periodontally healthy subjects and patients with chronic periodontitis. METHODS: 40 subjects were included in the healthy group and 39 subjects were included in the diseased group in this study. Cells and subgingival plaque samples were collected. The extracted DNA was amplified with universal primers and P. gingivalis species-specific primer. RESULTS: P. gingivalis was detected in 37.5% of subgingival plaque samples and 32.5% of buccal mucosa samples in the healthy subjects, but 69.23% of subgingival plaque samples and 46.15% of buccal mucosa samples in the periodontitis group. Highly statistically significant differences were observed between healthy and periodontitis groups in the detections of P. gingivalis of subgingival plaque samples. CONCLUSION: P. gingivalis may be one of oral flora because it can be detected in the healthy population and not lead to destruction of supporting structures of the teeth.

Adult↗
PubMed2005

Genetic variation within exon 2 of the MHC B-LB // gene in Tibetan chicken.

Genetic variation within exon 2 of chicken major histocompatibility complex B-LB // genes was investigated by PCR amplification, cloning and sequencing of a 374 bp fragment of the indigenous Tibetan chicken genomic DNA. Fifteen novel B-LB // alleles were found. Alignment and comparison of 18 allelic sequences from the individuals sampled revealed a total of 62 variable sites (total of 80 mutations) in exon 2, of which 41 were parsimony informative sites. The nucleotide diversity (pi) within the sequence of exon 2 was calculated to be 0.0718. Analysis of nucleotide variation confirmed a lower level of divergence (0.056 +/- 0.008) as estimated by average pairwise distance within the Tibetan chicken population than the five exotic breeds detected. The relative frequencies of synonymous and non-synonymous nucleotide substitutions within the region were 3.25 +/- 0.94% and 15.61 +/- 2.69% , respectively. These results indicated that the genetic variation within exon 2 seemed to have arisen largely by gene recombination and balancing selection. Alignment of the deduced amino acid sequences of beta1 domain coded by exon 2 revealed 11 synonymous mutations and 27 non-synonymous substitutions at the 38 separate sites. Fifty percent (12/24) of the proposed peptide-binding sites were variable within beta1 domain of chicken MHC B-LB // molecules, of which 11 were unique non-synonymous amino acid substitutions. These particular non-synonymous substitutions are considered to be associated with immunological specificity of MHC B-LB // molecule in Tibetan chicken, and they can provide a molecular biological basis for the study of disease resistance in chicken.

Animals↗
PubMed2005

[Semen quality and sperm morphologic study of infertile men with varicocele].

OBJECTIVE: To examine the semen quality and the sperm morphology in infertile men with varicocele. METHODS: Semen from 98 infertile men with varicocele were studied and those of 130 normal semen donors were taken as the control. Semen analysis was performed based on the methods described in the WHO manual and sperm morphology was evaluated by WHO criteria. RESULTS: A significantly reduced percentage of normal morphologic sperm and of forward progression were found in patients with varicocele comparing with those of the control (P <0.001). The head defects were observed as the predominant type of sperm malformation. CONCLUSION: The varicocele increases malformed sperm in ejaculates, which may result from impaired male fertility by varicocele. Sperm morphologic assessment with WHO criteria provides a sensitive and practical measurement of sperm damage in infertile men with varicocele.

Adult↗
PubMed2004

Preparation and property analysis of a hepatocyte targeting pH-sensitive liposome.

AIM: To develop a hepatocyte targeting pH-sensitive liposome for drug delivery based on active targeting technology mediated by asialoglycoprotein receptors. METHODS: Four types of targeting molecules with galactose residue were synthesized and mixed with pH-sensitive lipids DC-chol/DOPE to prepare liposome with integrated property of hepatocyte specificity and pH sensitivity. Liposome 18-gal was selected with the best transfection activity through cellular uptake experiment. Property analysis was made through experiments of competitive inhibition of receptors, red blood cell hemolysis, in vitro cytotoxicity test by MTS assay and mediation of inhibitory effects of antisense phosphorothioate ODN on gene expression, etc. RESULTS: Liposome 18-gal had the desired properties of hepatocyte specificity, pH sensitivity, low cytotoxicity, and high transfection efficiency. CONCLUSION: Liposome 18-gal can be further developed as a potential hepatocyte- targeting delivery system.

Cell Line, Tumor↗
PubMed2004

A p105-based inhibitor broadly represses NF-kappa B activities.

An IkappaBalpha-based NF-kappaB super repressor (sr) has been used widely for studying genes regulated by NF-kappaB transcription factors. Repression of NF-kappaB by IkappaBalpha(sr) also facilitates tumor necrosis factor alpha-induced apoptosis in the cell. However, IkappaBalpha primarily targets RelA and c-Rel-containing complexes, leaving other NF-kappaB/Rel protein complexes, such as p50 and p52 homodimers, and RelB heterodimers uninhibited. Because these atypical NF-kappaB complexes also contribute to gene regulation and are activated in pathological conditions, broad inhibition of all NF-kappaB species is of significant pharmacological and clinical interests. We have designed, generated, and tested a p105-based NF-kappaB super repressor. We showed that p105(sr), which no longer generates p50 and undergoes signal-induced degradation, effectively inhibits all NF-kappaB activities. In addition, we also demonstrated that p105(sr) significantly enhances tumor necrosis factor alpha-mediated killing of MT1/2 skin papilloma cells where p50 homodimer activity is elevated. Our results suggest that p105(sr) is a broader range and effective NF-kappaB super repressor and can potentially be used in cells where a noncanonical NF-kappaB activity is dominant or multiple NF-kappaB activities are activated.

Animals↗
PubMed2004

Platinum particles-modified electrode for HPLC with pulsed amperometric detection of thiols in rat striatum.

A new chemically modified electrode based on the immobilization of Pt particles is fabricated and exhibits electrocatalytic oxidation for L-cysteine (L-Cys), glutathione (GSH) and penicillamine (PEN) with relatively high sensitivity. It is also adaptable to HPLC for pulsed amperometric detection (PAD) of these thiols. PAD largely improves the detection sensitivity because the alternated polarizations can effectively clean and reactivate the electrode surface. It is shown that the peak currents of L-Cys, GSH and PEN are linear to their concentrations, with the calculated detection limit of 1.1 x 10(-7), 1.8 x 10(-7) and 3.8 x 10(-7) mol L(-1), respectively (S/N = 3). The method has been successfully applied to assess the contents of L-Cys and GSH in rat striatal microdialysates. The average contents of the two analytes in rat striatum are 2.6 x 10(-6) and 2.8 x 10(-6) mol L(-1), respectively.

Animals↗
PubMed2004

Detection of C677T mutation in methylenetetrahydrofolate reductase gene by denaturing high performance liquid chromatography.

In this paper, we described an assay for the detection of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene using denaturing high-performance liquid chromatography (DHPLC). The conditions for DHPLC analysis were systematically investigated based on a general HPLC instrument (Prostar VARIAN). A 225 bp DNA fragment covering the 677 site of MTHFR gene was amplified by PCR technology using the purified DNA from whole blood or whole blood as template DNA. PCR products were directly injected without the need for purification. The C677T mutation could be clearly distinguished by DHPLC technology. Our data demonstrated that DHPLC was a powerful and alternative tool for detection of genetic variants and single-nucleotide polymorphisms to electrophoresis technology.

Base Sequence↗
PubMed2004

Experimental study of adenovirus vector mediated-hVEGF165 gene on prevention of restenosis after angioplasty.

This study evaluated the effects of adenovirus vector mediated human vascular endothelial growth factor-165 (hVEGF165) gene on prevention of restenosis after angioplasty. Rabbit models of bilateral carotid artery injury were established by balloon denudation. The recombinant adenoviruses containing hVEGF165 cDNA was directly injected into left side of the injured carotid arteries. On day 3 and week 3 after transfection the expression of VEGF was observed by RT-PCR and immunohistochemistry. The thrombokinesis, reendothelialization (rET) and intimal hyperplasia in carotid arteries were evaluated by computerized image analysis system 3 weeks after gene transfer. The changes in the VEGF gene-treated side were compared with the control side. Our results showed that 3 days and 3 weeks after hVEGF165 gene transfer the VEGF mRNA and antigen expression were detected in vivo. 3 weeks after the transfer, the carotid artery rET was markedly better in the VEGF gene-treated group compared with the control. The thrombokinesis, intima area/media area (I/M), maximal intimal and medial thicknesses (ITmax and MTmax) demonstrated a statistically significant decrease in arteries treated with VEGF gene as compared with the control group. It is concluded that VEGF gene transfer could be achieved by intra-arterial injection of recombinant adenoviruses. It might accelerate the restoration of endothelial integrity, inhibit thrombokinesis and attenuate intimal hyperplasia in the injured arteries after VEGF gene transfer. This procedure could be useful in preventing restenosis after angioplasty.

Adenoviridae↗
PubMed2004

Down-regulation of beta catenin inhibits the growth of esophageal carcinoma cells.

INTRODUCTION: Esophageal cancer remains a highly lethal malignancy, with therapeutic options of limited efficacy in the majority of patients. Understanding the molecular events involved in the pathogenesis of esophageal cancer offers insight into potential targets for treatment. Beta catenin and Wnt signaling abnormalities are involved in the development of both adenocarcinoma and squamous carcinoma of the esophagus. We hypothesized that down-regulation of beta catenin would inhibit the growth of human esophageal cancer. METHODS: A human esophageal squamous cell carcinoma cell line (TE10) was treated with phosphorothioate antisense oligonucleotides to beta catenin. The cells were subsequently assayed for beta catenin mRNA and protein by real-time polymerase chain reaction and Western blot. Beta catenin transcriptional activity was determined by TOPFlash assay. Cell viability and growth was assessed by methyl-thiazol-diphenyl-tetrazolium assay and trypan blue exclusion. A colorimetric assay was employed to assess caspase 3 activity, and flow cytometry was done to determine percentage of cells in a given phase of the cell cycle. RESULTS: Following antisense treatment, beta catenin mRNA and protein concentration were decreased. There was corresponding decrease in beta catenin-transcription factor-dependent transcription. Treatment with beta catenin antisense resulted in significantly decreased cell viability and proliferation. The mechanism appears to be increased induction of apoptosis. CONCLUSIONS: These data suggest a potential role for the targeting of beta catenin in the treatment of esophageal cancer.

Analysis of Variance↗
PubMed2004

Urotensin-II activates L-arginine/nitric oxide pathway in isolated rat aortic adventitia.

Urotensin-II (U-II), a cyclic peptide widely expressed in blood vessels, has diverse vascular actions that range from potent vasoconstriction to vasodilation. Although, U-II-induced vasodilation has been shown to be partially dependent on nitric oxide (NO), the involvement of vascular adventitia-derived NO, remains unknown. The present study aimed to elucidate the activation of U-II on L-arginine/NO pathway in isolated rat aortic adventitia. In adventitia of thoracic and abdominal aortas, the l-arginine/NO pathway was similarly characterized: the uptake of l-[(3)H]arginine was Na(+)-independent, with the peak occurring over around 40 min incubation; the total NO synthase (NOS) activity was mostly calcium-independent (>90%), and significantly inhibited by a specific iNOS inhibitor AMT; the production of NO metabolites nitrate and nitrite (NO(x)) was stimulated by L-arginine but not by D-arginine. In aortic adventitia exposed to rat U-II (10(-9) and 10(-8)M) for 6 h, the V(max) of l-[(3)H]arginine uptake over 40 min incubation was significantly increased, while the K(m) of l-[(3)H]arginine uptake showed no significant change. Besides, the iNOS mRNA level was up-regulated, the total NOS activity, largely calcium-independent, was significantly induced, and the NO(x) production was significantly stimulated by U-II. According to the same protocol as U-II, the positive control lipopolysaccharide (LPS, 10 microg/ml), which had been established to activate adventitial L-arginine/NO pathway, increased l-[(3)H]arginine uptake, iNOS activity and NO(x) production to a greater extent than U-II. In addition, the total NOS activities induced by 3 and 6h incubation of U-II and LPS were significantly inhibited by a specific inhibitor of protein synthesis, actinomycin D. In conclusion, the results showed that rat U-II activated L-arginine/NOS/NO pathway in rat aortic adventitia, suggesting a potential contributive role of adventitia-derived NO in the vasodilator response of U-II.

Animals↗
PubMed2004

HSP70 and GRP78 induced by endothelin-1 pretreatment enhance tolerance to hypoxia in cultured neonatal rat cardiomyocytes.

The heat shock protein 70 and glucose-regulated protein 78 have been shown to protect cells against deleterious stimuli. This study was performed to determine whether endothelin-1 pretreatment could increase cardiomyocyte tolerance to hypoxia and induce heat shock protein 70 and glucose-regulated protein 78 expression. Cultured cardiomyocytes were treated with endothelin-1 at doses of 0.01, 0.1 and 1.0 nmol/L for 10 minutes followed by 10 minutes endothelin-1-free normal medium prior to 12 hours hypoxia. Lactate dehydrogenase activity and malondialdehyde level in the medium were determined at the end of hypoxia, and myocyte heat shock protein 70 and glucose-regulated protein 78 were assayed with Western blot. Lactate dehydrogenase activity and malondialdehyde content in the medium were significantly elevated after hypoxia (P < 0.01, n = 6). Heat shock protein 70 and glucoseregulated protein 78 expression in cardiomyocytes also increased significantly after hypoxia (P < 0.01 vs control, n = 3). Endothelin- 1 pretreatment reduced lactate dehydrogenase and malondialdehyde after hypoxia, and increased heat shock protein 70 and glucoseregulated protein 78 levels during normal culture and hypoxia. Glucose-regulated protein 78 antisense oligodeoxynucleotide partially abrogated the protective effect of endothelin-1 pretreatment on hypoxic cardiomyocyte injury. This study indicated that endothelin-1 pretreatment could protect hypoxic cardiomyocytes and might exert this effect through upregulation of heat shock protein 70 and glucose-regulated protein 78.

Animals↗
PubMed2004

Itinerary of hepatitis B viruses: delineation of restriction points critical for infectious entry.

Little is known about cellular determinants essential for human hepatitis B virus infection. Using the duck hepatitis B virus as a model, we first established a sensitive binding assay for both virions and subviral particles and subsequently elucidated the characteristics of the early viral entry steps. The infection itinerary was found to initiate with the attachment of viral particles to a low number of binding sites on hepatocytes (about 10(4) per cell). Virus internalization was fully accomplished in less than 3 h but was then followed by a period of unprecedented length, about 14 h, until completion of nuclear import of the viral genome. Steps subsequent to virus entry depended on both intact microtubules and their dynamic turnover but not on actin cytoskeleton. Notably, cytoplasmic trafficking of viral particles and emergence of nuclear covalently closed circular DNA requires microtubules during entry only at and for specific time periods. Taken together, these data disclose for the first time a series of steps and their kinetics that are essential for the entry of hepatitis B viruses into hepatocytes and are different from those of any other virus reported so far.

Actins↗
PubMed2004

Polarographic determination of total iron content using a Fe(2+/3+)-Methylthymol Blue-NO2- system.

In the buffer solution of NH3-NH4Cl (pH = 8.5, 0.04 mol l(-1)), iron-Methylthymol Blue (MTB) can produce a sensitive polarographic wave at -1.10 V (vs. SCE) in the NaNO2. The peak current is linear with the concentration of the iron in the range of 3 x 10(-8)-5 x 10(-6) mol l(-1), and the detection limit is 1 x 10(-8) mol l(-1). By studying the characteristics of the wave and the electrode reaction mechanism, we can prove that the catalytic wave is an adsorption wave and that the peak current comes from the reduction of Fe(II). The molar ratio of iron to ligand was found to be 1:1. Adsorption particles are neutral molecules, the saturated adsorption quantity of the complex on the mercury electrode is 1.92 x 10(-9) mol cm(-2), according with the Frumkin isothermal formula. In the experiments, the adsorption coefficient (beta) is 4.05 x 10(5); the adsorption factor (gamma) is 0.70: the electron transfer number (n) is 2; the free energy (deltaG(o)) is 31.99 kJ mol(-1); the transfer coefficient of the irreversible adsorption is 0.42-0.45; and the reaction velocity constant (Ks) is 1.35 s(-1). This method, whose result is satisfying, can be applied to the detection of trace total iron contents in medicinal products.

Journal Article↗