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Biomedical subjects

N Li

Publications and source records attributed to N Li.

At least 37 records · Page 2Linked to original sources
PubMed2006

Clinical and serological follow-up studies of endemic pemphigus foliaceus (fogo selvagem) in Western Parana, Brazil (2001-2002).

BACKGROUND: Fogo selvagem (FS) has been described in several regions of Brazil, including the Western regions of the state of Parana. In 1990, Empinotti et al. reported case studies of 213 patients with FS that were collected from 1976 to 1988. The same author (J.C.E.) has observed that the frequency of cases in these regions of Parana has decreased. OBJECTIVES: The purpose of this study was to clinically and serologically evaluate a small group of the patients originally reported in 1990 and compare data with a group of control individuals. These patients were treated at the onset of the disease with systemic steroids. PATIENTS AND METHODS: Patients with FS, their unaffected relatives (n = 80) and genetically unrelated controls (n = 15) were identified during a field study from 1 May 2001 to 30 June 2002. Sera from nine patients with FS and six normal controls that were collected in the 1976-1988 evaluation were available for this study. The sera were tested by indirect immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation using recombinant human desmoglein 1 (Dsg1). RESULTS: Only 16 of the originally identified 213 patients with FS were found during the field studies. Thirteen of the 16 patients were in clinical and serological remission; 20% of normal controls (19 of 95) were positive in the Dsg1 ELISA. The majority of these subjects (17 of 19) were genetically related to FS patients. Six normal controls that were positive in the Dsg1 ELISA in the original survey were found to be negative or weakly positive in this evaluation. CONCLUSION: The reduced frequency of positive serological markers of disease in patients and normal controls from Western Parana, as well as the absence of recurrent disease in previously identified patients, suggest that environmental antigenic stimulation of the population at risk may have decreased in recent years.

Autoantibodies↗
PubMed2006

Functional variants of the lipoprotein lipase gene and the risk of preeclampsia among non-Hispanic Caucasian women.

Hypertriglyceridemia is an important pathophysiologic feature of preeclampsia, a common vascular disorder of pregnancy. Three well-documented functional variants (N291S, S447X, and D9N) of the lipoprotein lipase gene were related to hypertriglyceridemia. Results from the only two studies concerning the relationship between these variants and preeclampsia risk have been inconsistent. We investigated this relationship in a case-control study including 144 preeclamptic and 290 normotensive pregnant women (all non-Hispanic Caucasians). We estimated odds ratios (OR) and 95% confidence intervals (CI) adjusted for maternal age, pre-pregnancy body mass index, and parity. After adjusting for covariates, women with the 291 N/S or S/S genotype had significantly increased risk of preeclampsia (OR 6.9, 95% CI 1.9-25.4) compared with women with the common 291N/N genotype. The 447 S/X or X/X genotype was not significantly associated with preeclampsia risk. The frequency of the 9N variant allele was 1.8% in controls, while this allele was not observed among cases. Haplotype 9D/291S/447S was strongly associated with higher risk of preeclampsia as compared with the most common haplotype 9D/291N/447S (adjusted OR 6.6, 95% CI 1.7-25.0). Results from our study support the thesis that abnormal lipid metabolism is important in the pathogenesis of preeclampsia.

Adult↗
PubMed2006

Cytogenetic mapping of 11 functional genes to chicken chromosomes by fluorescence in situ hybridization.

With chicken bacterial artificial chromosome (BAC) DNA as probes, 11 non-assigned functional genes were localized to chicken chromosomes 1 or 2 by fluorescence in situ hybridization (FISH). The 11 genes and their chromosomal positions are as follows: ALVEB5, 1p26-24; ACO2, 1p16-14; HSP108, 1p14-13; CD4, 1q11; HSD3B; 1q11; SOD1, 1q14-21; LAMP1, 1q24-31; P2Y5, 1q35-36; EN2, 2p31-24; NPY, 2p14-13 and CA2, 2q31-32. Metaphase chromosome spreads used for hybridization were prepared from embryonic chicken fibroblast cultures. The gene position was identified according to the international standardized G-banded karyotype of chicken by measuring the relative fractional length from the telomere of the p-arm to the hybridization signal (FLpter). The 11 genes mapped newly will enrich the cytogenetic map and serve as additional anchor markers for integrating the cytogenetic map with the genetic map of chicken.

Animals↗
PubMed2006

Platelet-lymphocyte conjugation differs between lymphocyte subpopulations.

BACKGROUND: Platelets can bind to, and thereby influence, lymphocyte function. OBJECTIVE: The propensities of different lymphocyte subpopulations to form platelet-lymphocyte conjugates/aggregates (P-Lym) was investigated using four-color whole blood flow cytometry. RESULTS: P-Lym constituted approximately 3% of circulating lymphocytes. Platelet conjugation was most common among large (monocyte-sized) lymphocytes. Platelet activation by ADP slightly increased platelet-T-cell conjugation, mainly to T-cytolytic (Tc) cells, but markedly elevated platelet-natural killer (NK)-cell conjugation. T-cell activation by phytohemagglutinin increased heterotypic conjugation among both T-helper (TH) and Tc cells, whilst NK-cell activation by interleukin-2 affected platelet-NK-cell aggregation little. Neither platelet activation nor lipopolysaccharides-induced B-cell activation enhanced platelet-B-cell aggregation. Activation-dependent heterotypic conjugation was mainly found among large cells, with increased percentages of conjugated cells and more platelets bound per lymphocyte. P-Lym formation initiated by platelet activation was abolished by P-selectin blockade, and tended to be reduced by inhibition of GPIIb/IIIa, CD11b, or CD40L. P-Lym formation initiated by lymphocyte activation was partially inhibited by each of these blocking agents, but more markedly inhibited when the blocking agents were combined. CONCLUSIONS: Platelets selectively bind to larger and activated lymphocytes. T-lymphocyte activation enhances platelet-T-cell aggregation. Platelet activation enhances platelet-Tc aggregation slightly and platelet-NK-cell aggregation markedly, while cellular activation affects platelet-B-cell aggregation little. P-selectin ligation is essential, but GPIIb/IIIa, CD40L, and CD11b also contribute to the heterotypic conjugation.

Adult↗
PubMed2006

cDNA cloning, genomic structure, chromosomal mapping and expression analysis of ADIPOQ (adiponectin) in chicken.

We report sequence, tissue expression and map position data for the adiponectin gene (ADIPOQ) in chicken. This gene is involved in adipocyte differentiation in mammals and may play similar roles in chicken. The complete coding sequence of chicken ADIPOQ encodes a 244 amino acid protein. The coding region of the chicken ADIPOQ is organized in two exons and spans an approximately 2.1 kb genomic region. Domain/motif structures of the adiponectin protein among chicken and mammalian homologs are highly conserved. Reverse transcription-PCR revealed chicken ADIPOQ mRNA displayed high expression levels in fat tissue, heart, stomach and skin and weak expression in muscle. Analysis of a radiation hybrid panel indicated that ADIPOQ showed the most significant linkage to FOXL2 (LOD = 12.63, 12 cR) and ATSV (LOD = 7.53, 3 cR) both of which are located on chicken chromosome 9. Information provided in this study will be useful in further studies to determine the role the adiponectin gene plays in the regulation of glucose and lipid metabolism and body weight in chicken.

Adiponectin↗
PubMed2006

Morphologies of fibroblast cells cultured on surfaces of PHB films implanted by hydroxyl ions.

Polyhydroxybutyrate (PHB) films were implanted with 40 keV hydroxyl ions with fluences ranging from 1 x 10(12) to 1 x 10(15) ions/cm2, respectively. The as-implanted PHB films were characterized by scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA) and water contact angle measurements. The surface structures and properties of the as-implanted PHB films were closely related with hydroxyl ion fluence. They were further investigated by inoculating 3T6 fibroblasts cells on their surfaces. Morphologies of the 3T6 fibroblast cells cultured on surfaces of the as-implanted PHB films were observed by SEM. Characterization of the cultural 3T6 cells was analyzed qualitatively. The preliminary experimental results reveal that the bioactivity of the PHB films modified by hydroxyl ion implantation was improved at different levels, and the fluence of 1 x 10(13) ions/cm2 is optimal for PHB film.

Animals↗
PubMed2006

Effects of high-volume continuous hemofiltration on experimental pancreatitis associated lung injury in pigs.

OBJECTIVE: To investigate the effect of high-volume continuous hemofiltration on experimental pancreatitis associated lung injury (PALI) in pigs. METHODS: Animals had severe acute pancreatitis (SAP) induced by intraductal injection of sodium taurocholate and trypsin and were randomly assigned to three groups: 1) Controls, 2) Low-volume (LV) (20 ml/kg/h) continuous venovenous hemofiltration (CVVH) and 3) High-volume (HV) (100 ml/kg/h) CVVH at the onset of the induction of SAP. Systemic and pulmonary hemodynamic index were monitored intermittently. At the same time, arterial oxygen tension (PaO 2 ), cytokines and activated NF- ê B levels of peripheral blood mononuclear cell were measured. After the animals died, the degree of microscopic lung injury was judged and scored. RESULTS: The median survival times of control, low-volume and high-volume groups were respectively 41 h, 50 h and 65 h. Temperatures in high-volume CVVH group were more steady than in control and LV CVVH groups (p<0.01). MPAP was significantly decreased by 4-5 mmHg in the HV CVVH group after 12 h of treatment. PaO(2) was significantly higher in HV group than in LV group at 6 h , 12 h, 24 h and 48 h (p<0.01). HV CVVH resulted in significant reductions not only in interstitial edema and atelectasis but also hemorrhages, hyaline membranes, microthrombi and total lung injury histology score. Plasma cytokines in the high-volume group were significantly lower than in the LV and control groups. In the HV group, the expression of NF- ê B activation at 6 h, 12 h and 24 h was lower than in the control and LV groups respectively. CONCLUSION: CVVH can reduce pulmonary edema and the severity of PALI in pigs with high-volume CVVH being significantly better than low-volume CVVH. The beneficial effects of CVVH on arterial oxygenation and pulmonary function may be connected with improvements in systemic hemodynamics, reduction in plasma cytokine concentration and decreased activity of NF- ê B in peripheral blood mononuclear cells.

Animals↗
PubMed2006

Development of chitosan-based granular adsorbents for enhanced and selective adsorption performance in heavy metal removal.

Novel chitosan-based granular adsorbents were developed for enhanced and selective separation of heavy metal ions. The research included the synthesis of chitosan hydrogel beads, the cross-linking of the hydrogel beads with ethylene glycol diglycidyl ether (EGDE) in a conventional and a novel amine-shielded method, the functionalization of the chitosan beads through surface grafting of polyacrylamide via a surfaceinitiated atom transfer radical polymerization (ATRP) method, and the examination of the adsorption performance of the various types of chitosan beads in the removal of heavy metal ions. It was found that chitosan beads were effective in heavy metal adsorption, the conventional cross-linking method improved the acidic stability of the beads but reduced their adsorption capacity, the novel amine-shielded cross-linking method retained the good adsorption capacity while it improved the acidic stability of the beads, and the grafting of polyacrylamide on chitosan beads not only enhanced the adsorption capacity but also provided the beads with excellent selectivity for mercury over lead ions. XPS analyses indicated that the adsorption of metal ions on chitosan beads was mainly attributed to the amine groups of chitosan, the novel amine-shielded cross-linking method preserved most of the amine groups from being consumed by the cross-linking process and hence improved the adsorption capacity of the cross-linked chitosan beads, and the many amide groups from the polyacrylamide grafted on the chitosan beads increased the adsorption capacity and also made possible selective adsorption of mercury ions because the amide groups can form covalent bonds with mercury ions.

Adsorption↗
PubMed2006

Cloning of pig parotid secretory protein gene upstream promoter and the establishment of a transgenic mouse model expressing bacterial phytase for agricultural phosphorus pollution control.

This study examined the feasibility of using the promoter of the pig parotid secretory protein (PSP) gene for expression of the phytase transgene in mouse models. The pig parotid secretory protein gene is specifically expressed at high levels in the salivary glands. The 10-kb upstream promoter region of the gene necessary for tissue-specific expression has been identified. We have constructed phytase transgenes composed of the appA phytase gene from Escherichia coli driven by the upstream promoter region of the pig PSP gene with a 3' tail of either bovine growth hormone or the pig PSP gene polyadenylation signal. Transgenic mouse models with the construct showed that the upstream region of the pig PSP gene is sufficient for directing the expression of phytase transgenes in the saliva. Expression of salivary phytase reduced fecal phytate by 8.5 and 12.5% in 2 transgenic mouse lines, respectively. These results suggest that the expression of phytase in salivary glands of monogastric animals offers a promising biological approach to relieve the requirement for dietary phosphate supplements and to reduce phosphorus pollution from animal agriculture.

6-Phytase↗
PubMed2006

Expression and bioactivity of recombinant human lysozyme in the milk of transgenic mice.

Human milk lysozyme is an important protein for innate immunity, but human breast milk is a fairly poor source for commercial production of this enzyme. Research on the expression of recombinant human lysozyme (rHlys) is therefore potentially valuable to the dairy industry. In this study, 2 different kinds of transgenic mice, PBC-hLY and PBC-sighLY, were generated and used as system models to express rHlys. Six lines of PBC-hLY transgenic mice with human lysozyme genomic DNA-based constructs were generated, and a maximum expression level of rHlys approaching 0.154 mg/mL was achieved. Antibacterial activity of the whey from PBC-hLY female transgenic mice was determined by a turbidimetric assay. Results showed that antibacterial activity of the whey was strongly enhanced, and confirmed that rHlys retained full activity. For rHlys to be secreted efficiently into the milk of transgenic mice, 5 lines of mice were also generated, in which the signal peptide DNA of bovine beta-casein was substituted for that of lysozyme in PBC-hLY transgenic mice. Compared with PBC-hLY transgenic mice, both the expression levels of rHlys and the antibacterial activity of the whey were much higher in the PBC-sighLY transgenic mice. The concentration of rHlys in one of these mice amounted to 1.405 mg/mL-3 times higher than the level in human whey. The antibacterial activity of the whey was also 3 times higher than that of human whey. The rHlys from both PBC-hLY and PBC-sighLY transgenic mice had the same antibacterial activity as human milk lysozyme. The effect of the signal peptide and copy numbers of the transgene on expression of rHlys was also evaluated. This work will certainly permit a better understanding of how mammary gland bioreactor systems can be applied to produce rHlys in other mammals, such as cattle.

Animals↗
PubMed2006

Molecular variability of the coat protein gene of Potato virus Y from tobacco in China.

Thirty-three tobacco samples showing typical symptoms of Potato virus Y (PVY) infection were obtained from tobacco fields in various regions of China. The results of indirect ELISA confirmed the infection with PVY. All the isolates had a capacity to infect tobacco systemically in greenhouse, causing either of two main symptoms: veinal necrosis and mosaic. The nucleotide and amino acid sequences of the coat protein (CP) gene and protein, respectively, of the isolates were determined. Comparison of the isolates revealed a high conservation of the CP gene with an identity of 83.2%. A phylogenetic tree of 41 Chinese isolates of PVY, based on complete CP gene, showed 3 groups corresponding to the strains PVYNTN (A group), PVYO (C group) and a putative new strain similar to PVYN (B group). The amino acid sequences of complete CP protein of the isolates showed an identity of 87.6%. The highest identity was observed in the C-terminal half of the CP protein, where only 11 amino acid differences could be observed, in contrast to the N-terminal half with 22 differences.

Amino Acid Sequence↗
PubMed2005

Analgesic effect of electroacupuncture on complete Freund's adjuvant-induced inflammatory pain in mice: a model of antipain treatment by acupuncture in mice.

Electroacupuncture (EA) was applied bilaterally to the acupoints of Zu-san-li (ST-36) and Kun-lun (BL-60) in the hindlimbs of mice. The therapeutic effect of EA on inflammatory pain induced by an ipsilateral injection of complete Freund's adjuvant (CFA) into the right paw of the mouse was investigated in this study. The time of paw-withdrawal latency (PWL) was used as an indicator for judging the intensity of the pain induced by the CFA injection. The EA effects were divided into immediate (PWL tests within 2 h after EA treatment) and cumulative (PWL tests during and after repetitive EA treatments for 3 weeks) effects. As immediate effects, PWL was significantly shortened in the CFA-injected paw, but was again prolonged 20 min after an EA treatment and lasted until 30 min after. As cumulative effects, PWL was significantly shortened in the CFA-injected paw, but recovered from the 2nd to the 8th day during repetitive EA treatments. No such effects could be observed after sham EA treatment, which resulted in behavior similar to that in untreated animals. These results demonstrate that the CFA-induced inflammatory pain in mice is an ideal model system for the investigation of EA effects and may serve as a valuable reference for the clinical treatment of inflammatory pain in human beings. Furthermore, the mouse pain model opens the possibility to apply the investigation also to transgenic mice.

Acupuncture Points↗
PubMed2005

Interpretation of the ultrasonic effect on induction time during BaSO4 homogeneous nucleation by a cluster coagulation model.

The effects of power ultrasound on the induction time of BaSO4 are studied experimentally and theoretically. In the experiments, barium sulfate is precipitated by mixing aqueous BaCl2 solution and Na2SO4 solution. The induction time is identified and measured by recording the change of turbidity in solution. Various energy inputs are used to investigate the effect of energy on nucleation. The results show that the induction time decreases with increasing supersaturation and increasing energy input. Employing the classical nucleation theory, the interfacial tension is estimated. In addition, the ultrasonic effects on nucleation order (n) and the nucleation coefficient (kN) are also investigated. A cluster coagulation model, which brings together the current nucleation models and the theories describing the behavior of colloidal suspensions, was applied to estimate the induction time under various energy inputs. A comparison between the results of model and the results of experiments shows that the number of monomers in dominating clusters (g) in the solution remains constant with increasing of energy input.

Journal Article↗
PubMed2005

Polyunsaturated eicosapentaenoic acid changes lipid composition in lipid rafts.

BACKGROUND: Polyunsaturated fatty acids (PUFAs) modulate immune responses particularly by affecting T cell function and are applied clinically as adjuvant immunosuppressants in the treatment of various inflammatory diseases. However, the molecular mechanisms of PUFA-induced immunosuppressive effects are not yet elucidated. Membrane lipid rafts are functional plasma membrane microdomains characterized by a unique lipid environment. Since lipid interactions are crucial for the formation of lipid rafts, the immunomodulatory effects of PUFAs may be due to changes of fatty acid composition in lipid rafts. AIM OF THE STUDY: We investigated the effects of eicosapentaenoic acid (EPA, 20:5 n - 3) supplementation on modulating lipid composition and fatty acyl substitution in their cytoplasmic and exoplasmic lipid leaflet in lipid rafts. METHODS: The human Jurkat E6-1 T cells were cultured in EPA-supplemented medium and the cells treated with stearic acid served as a control. Lipid rafts were isolated by discontinuous sucrose density gradient ultracentrifugation. The lipids in raft and soluble fractions from EPA-treated and control T cells were extracted and separated by gas chromatography. Raft phospholipids were analyzed by mass spectrometry. RESULTS: Our results showed that EPA treatment could alter lipid composition resulting in a considerable increase of unsaturated fatty acyl chains in lipid rafts from EPA-treated T cells compared with control cells. Effective incorporation of EPA to rafts was not only in the exoplasmic but also in the cytoplasmic membrane lipid leaflet. EPA treatment altered the lipid environment in lipid rafts. EPA presented an inhibiting effect on Jurkat T cells proliferation and inhibited IL-2Ralpha expression on the surface of T cells. CONCLUSIONS: Our data provided evidence for an important modification in lipid composition of membrane lipid rafts and T cell function by EPA supplementation.

Cell Division↗
PubMed2005

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats.

The subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.

Administration, Oral↗
PubMed2005

Trophic effect of enteral rehabilitative therapy in rat small bowel transplantation.

INTRODUCTION: We aimed to observe the trophic effects on graft structure and recipient metabolism of enteral rehabilitative therapy in rat small bowel transplantation (SBT). METHODS: Forty-eight recipients of rat allogeneic heterotopic SBT (Sprague-Dawley to Wistar rat) were divided into four groups randomly according to the presence of glutamine or growth hormone in the nutritional support regimen. We compared the histologic indices of graft mucosa and metabolic variables, including changes in body weight, nitrogen balance, urinary 3-methyl histidine excretion, and plasma albumin levels during 14 days after transplantation. RESULTS: Glutamine and growth hormone promoted recovery of graft structure and improved recipient protein metabolism, as evidenced by indices of the enteral rehabilitative therapy. CONCLUSIONS: Glutamine and growth hormone potentiated their effects in enteral rehabilitative therapy, which produced potent trophic effects on graft structure and recipient metabolism in rat SBT.

Animals↗