Biomedical subjects

H Wei

Publications and source records attributed to H Wei.

At least 55 records · Page 3Linked to original sources

PubMed2001

Gene expression profiling in human fetal liver and identification of tissue- and developmental-stage-specific genes through compiled expression profiles and efficient cloning of full-length cDNAs.

Fetal liver intriguingly consists of hepatic parenchymal cells and hematopoietic stem/progenitor cells. Human fetal liver aged 22 wk of gestation (HFL22w) corresponds to the turning point between immigration and emigration of the hematopoietic system. To gain further molecular insight into its developmental and functional characteristics, HFL22w was studied by generating expressed sequence tags (ESTs) and by analyzing the compiled expression profiles of liver at different developmental stages. A total of 13,077 ESTs were sequenced from a 3'-directed cDNA library of HFL22w, and classified as follows: 5819 (44.5%) matched to known genes; 5460 (41.8%) exhibited no significant homology to known genes; and the remaining 1798 (13.7%) were genomic sequences of unknown function, mitochondrial genomic sequences, or repetitive sequences. Integration of ESTs of known human genes generated a profile including 1660 genes that could be divided into 15 gene categories according to their functions. Genes related to general housekeeping, ESTs associated with hematopoiesis, and liver-specific genes were highly expressed. Genes for signal transduction and those associated with diseases, abnormalities, or transcription regulation were also noticeably active. By comparing the expression profiles, we identified six gene groups that were associated with different developmental stages of human fetal liver, tumorigenesis, different physiological functions of Itoh cells against the other types of hepatic cells, and fetal hematopoiesis. The gene expression profile therefore reflected the unique functional characteristics of HFL22w remarkably. Meanwhile, 110 full-length cDNAs of novel genes were cloned and sequenced. These novel genes might contribute to our understanding of the unique functional characteristics of the human fetal liver at 22 wk.

Cloning, Molecular↗

PubMed2001

Stable inversion method for a polarized-lidar: analysis and simulation.

A new inversion inhomogeneous atmosphere (IA) method that is more stable than Fernald's method for two-component (molecule and aerosol) scattering analysis of polarized Mie lidar signals is proposed and examined. The backscattering coefficient and the extinction-to-backscattering ratio (EBR) can be calculated for specified regions at which the depolarization ratio is less than that of molecule without further assumptions. The inversion procedure can be extended to both inward stepwise and outward stepwise integration algorithms. Simulation results indicate that a higher precision was achieved with the IA method than with Fernald's method in terms of error and random noise in estimating boundary value and EBR. Experimental results were also better with the IA method than with Fernald's method.

Journal Article↗

PubMed2001

Treatment effects on carbon dioxide retention in patients with obstructive sleep apnea-hypopnea syndrome.

OBJECTIVES: This study was designed to examine respiratory control in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), with or without CO(2) retention. METHODS: We recruited 10 body mass index-matched, apnea-hypopnea index-matched, age-matched, and lung function-matched OSAHS patients, according to their awake PaCO(2). Five patients were hypercapnic (PaCO(2), > or = 45 mm Hg), and five patients were eucapnic. Hypoxic responses (the ratio of the change in minute ventilation [DeltaV(E)] to the change in arterial oxygen saturation [DeltaSaO(2)] and the ratio of the change in mouth occlusion pressure over the first 100 ms of inspiration against an occluded airway [DeltaP(0.1)] to DeltaSaO(2)) and hypercapnic responses (DeltaV(E)/DeltaPCO(2) ratio and DeltaP(0.1)/DeltaPCO(2) ratio) were tested during wakefulness before treatment in all 10 patients, and before and during treatment (at 2, 4, and 6 weeks) with pressure support in the hypercapnic group. RESULTS: Hypercapnic patients had lower mean (+/- SD) DeltaV(E)/DeltaSaO(2) ratio than eucapnic patients (-0.17 +/- 0.04 vs -0.34 +/- 0.04 L /min/%SaO(2), respectively), lower mean DeltaP(0.1)/DeltaSaO(2) ratio (-0.04 +/- 0.02 vs -0.14 +/- 0.03 cm H(2)O/%SaO(2), respectively), and lower DeltaP(0.1)/DeltaPCO(2) ratio (0.23 +/- 0.1 vs 0.49 +/- 0.1 cm H(2)O/mm Hg, respectively) [p < 0.05]. After receiving noninvasive ventilation treatment, the hypercapnic and hypoxic responses of the hypercapnic patients increased. At 4 to 6 weeks, values for both responses had increased to within the normal range and PaCO(2) had fallen to < 45 mm Hg, while weight was unchanged. CONCLUSIONS: Depressed chemoresponsiveness plays a role that is independent of obesity in the development of CO(2) retention in some OSAHS patients, and it may be a response to sleep-disordered breathing.

Adult↗

PubMed2001

[The study of genetic variability of mtDNA in common laboratory inbred strains of mice].

The genetic variation of mtDNA among 7 common laboratory inbred strains of mice was analyzed by PCR-RFLP and PCR-SSCP techniques. D-loop, tRNA(Met + Glu + Ile) and ND3 fragments of mtDNA from the mices showed no variation in 46 endonuclease sites; Deeply analyzed by PCR-SSCP, the D-loop 5' fragment and 3' fragment of mtDNA from these mice also show no genetic variation. Because of maternal mode of inheritance of mtDNA, the results indicate that only one female lineage contributed to the formation of all these common inbred strains of mice.

Animals↗

PubMed2001

[Genetic analysis of 35 microsatellite loci in 5 lineages of xishuangbanna miniature pig inbred line].

The polymorphism of 35 microsatellites in 5 lineages of Xishuangbanna small-ear miniature pig inbred line (XMI) was analysed. Nmuber of alleles of each lineage was counted, and rates of homozygote for 35 microsatellite loci in 5 lineages were calculated. According to gene frequencies of 35 microsatellites polymorphism information content (PIC) and mean heterozygosity were calculated for each lineage, and genetic distances between these lineage were estimated. The dendrograms were obtained based on genetic distances. The results suggest that rates of homozygote in these lineage are all high, and that is the highest in lineage 151. The results also suggest that polymorphism information content and mean heterozygosity in all the lineages are low. Composition of alleles of each lineage was quite different and the genetic relationship between lineages accorded with the process of inbred line. So it is suggested that the inbreeding degree of 5 lineages of XMI are all high, and the richness of genetic diversity is lower than general commercial pig breeds. It also shows each lineage has been different groups with individual genes.

Alleles↗

PubMed2001

Pharmacodynamic and pharmacokinetic characterization of poly(ethylene glycol) conjugation to met-enkephalin analog [D-Pen2, D-Pen5]-enkephalin (DPDPE).

Poly(ethylene glycol), or PEG, conjugation to proteins and peptides is a growing technology used to enhance efficacy of therapeutics. This investigation assesses pharmacodynamic and pharmacokinetic characteristics of PEG-conjugated [D-Pen2,D-Pen5]-enkephalin (DPDPE), a met-enkephalin analog, in rodent (in vivo, in situ) and bovine (in vitro) systems. PEG-DPDPE showed increased analgesia (i.v.) compared with nonconjugated form (p < 0.01), despite a 172-fold lower binding affinity for the delta-opioid receptor. [125I]PEG-DPDPE had a 36-fold greater hydrophilicity (p < 0.01) and 12% increase in the unbound plasma protein fraction (p < 0.01), compared with [(125)I]DPDPE. [125I]PEG-DPDPE had a 2.5-fold increase in elimination half-life (p < 0.01), 2.7-fold decrease in volume of distribution (p < 0.01), and a 7-fold decrease in plasma clearance rate (p < 0.01) to [125I]DPDPE. Time course distribution showed significant concentration differences (p < 0.01) in plasma, whole blood, liver, gallbladder, gastrointestinal (GI) content, GI tract, kidneys, spleen, urine, and brain (brain, p < 0.05), between the conjugated and nonconjugated forms. Increased brain uptake of [(125)I]PEG-DPDPE corresponded to analgesia data. [125I]PEG-DPDPE in brain was shown to be 58.9% intact, with 41.1% existing as [125I]DPDPE (metabolite), whereas [125I]DPDPE was 25.7% intact in the brain (at 30 min). In vitro P-glycoprotein affinity was shown for [125I]DPDPE (p < 0.01) but not shown for [125I]PEG-DPDPE. In vitro saturable uptake, with 100 microM DPDPE, was shown for [125I]PEG-DPDPE (p < 0.05). In this study, PEG-conjugated DPDPE seems to act as a prodrug, enhancing peripheral pharmacokinetics, while undergoing hydrolysis in the brain and allowing nonconjugated DPDPE to act at the receptor.

Analgesics, Opioid↗

PubMed2001

[Effect of temperature on biodegradation of the petrochemicals in contaminated soil].

Temperature is a significant factor of the natural attenuation of the polluted soil. The effect of the temperature on the biodegradation rates and the half-life of the petrochemicals in contaminated soil were evaluated in this paper by the simulative experiments in laboratory. The results showed that the relationship between the temperature and the biodegradation rates was consistent with the exponential equation: K = 3145exp(-5233/T). According to the prediction of half-life of the biodegradation rates by the equation, the half-life at 5 degrees C, 10 degrees C, 20 degrees C and 30 degrees C were 1499 days, 1075 days, 572 days and 317 days respectively.

Biodegradation, Environmental↗

PubMed2001

[Effects of emodin on hepatic fibrosis in rats].

OBJECTIVE: To investigate the effect of emodin on hepatic fibrosis in rats and study its possible mechanism. METHODS: The rat hepatic fibrotic model was induced by the subcutaneous injection of 40% CCl(4) (twice a week for 6 weeks). The fibrotic rats were treated with low-dose, mediate-dose and high-dose emodin (20, 40 and 80 mg/kg body weight, once a day for 42 days). Liver function, serum hyaluronic acid, laminin, and liver hydroxyproline were determined, Histopathological changes were examined by optical microscopy. The expression of alpha-smooth muscle actin (alpha-SMA) in liver tissue were detected by immunohistochemical techniques. RESULTS: Compared with model group, it revealed that in emodin-treated rats: (1) Liver functions was improved, alanine transaminase (ALT) and alkaline phosphatase (AKP) obviously reduced (P<0.05 or <0.01), total protein (TP) and albumin (ALB) significantly increased (P<0.05 or <0.01). (2) Serum hyaluronic acid and laminin markedly reduced (P<0.05 or <0.01). (3) Liver hydroxyproline were significantly decreased (P<0.05 or <0.01). (4) The degrees of fibrosis were reduced (P<0.05). (5) The expression of alpha-SMA in liver tissue were ameliorated. CONCLUSIONS: Emodin has an effect on hepatic fibrosis in rats. The effect may be related to slowing hepatocyte injury and inhibiting liver alpha-SMA expressions.

Actins↗

PubMed2001

[Muscle pigment epithelium-derived factor gene associating with tumorigenesis of B16 melanoma].

OBJECTIVE: Random amplified polymorphic DNA (RAPD) analysis was used to detect the genomic variant in B16 melanoma, and to seek the tumor related DNA fragments. METHODS: Genomic DNA from B16 melanoma and C57BL/6J mouse normal tissues were amplified by RAPD with 105 random primers, the significantly different DNA fragments were isolated, cloned and sequenced. DNA sequences were analyzed with GenBank data. RESULTS: 24 of the 105 primers generated polymorphic profiles when the B16 melanoma RAPD profile was compared to that of its normal tissue DNA. By amplification of the primer AB8-5, a tumor band showing loss with respect to normal band was detected and this DNA fragment was designated as B8-5. B8-5 was a 610 bp fragment, the sequencing result of B8-5 showed 99% homology with muscle pigment epithelium-derived factor (PEDF) gene, and 100% homology with muscle pigment epithelium-derived factor mRNA. B8-5 was therefore regarded as PEDF gene. CONCLUSION: Our result found that allelic losses exist in PEDF gene, and therefore suggest that PEDF is associated with tumorigenesis of B16 melanoma.

Alleles↗

PubMed2001

The expression of AT1 receptor on hepatic stellate cells in rat fibrosis induced by CCl4.

OBJECTIVES: To assess the effect of an ACE inhibitor and an Ang II type 1 (AT1) receptor antagonist on preventing hepatic fibrosis induced by CCl4 in rats and to investigate whether there is the expression of AT1 receptors on hepatic stellate cells. METHODS: Studies were conducted in male Sprague-Dawley rats. Except for model group and control group, in three treated groups, either enalapril (5 mg/kg), or losartan (10 mg/kg), or enalapril + losartan were given to the fibrotic rats (daily gavage). Saline vehicle was given to the control group. After 6 weeks, liver fibrosis was assessed directly by hepatic morphometric analysis. The expression of AT1 receptors and alpha-smooth muscle actin (alpha-SMA) in liver tissue and isolated hepatic stellate cells (HSC) were detected by immunohistochemical techniques. RESULTS: Compared with the fibrosis in rats of the model group, rats treated with either enalapril or losartan, or a combination of two drugs, showed a limited expansion of the interstitium (P < 0.05), but no significant difference was observed among the three treated groups (P > 0.05). The expression of AT1 receptors was found in abundance in the fibrotic interstitium of the fibrotic rats, whereas in the normal control rats they were limited to the vascular wall. AT1 receptors were also expressed on activated HSC in culture plates. CONCLUSIONS: Angiotensin-converting enzyme inhibitors and AT1 blockers might slow the progression of hepatic fibrosis. Activated HSCs expressed AT1 receptors. Activation of RAS might be related to hepatic fibrogenesis induced by CCl4.

Alanine Transaminase↗

PubMed2001

[Changes of microarousal in OSAS patients during CPAP].

OBJECTIVE: To study the mechanism of microarousal, its clinical meaning and value in the diagnosis and treatment of sleep apnea-hypopnea syndrome (SAHS). METHODS: 270 snorers (218 men, 58 women) mean aged 48 years underwent standard polysomnography (PSG), from which AHI, sleep latency (SL), number of oxygen desaturation >/= 4% per hour (ODI(4)) and microarousal index (MAI) were calculated. The overnight PSG recordings were also repeated during nCPAP in 28 patients, who have filled in the Epworth Sleep Score (ESS) before and after the treatment to evaluate the improvement of daytime sleepiness. RESULTS: Of the 270 snorers, there were 247 SAHS patients. Their AHI, ODI(4), MAI and SL were (43 +/- 27)/h, (44 +/- 23)/h, (29 +/- 16)/h and (12 +/- 17) min, respectively. AHI and MAI, ODI(4) and MAI were both positively correlated (r = 0.38, both P < 0.001). MAI and SL were negatively correlated (r = -0.15, P = 0.02), while AHI and SL, ODI(4) and SL were not correlated (r = -0.09, -0.02, P > 0.1). Of the 28 patients after CPAP, ODI(4) decreased from (48 +/- 25)/h to (4 +/- 9)/h, MAI decreased from (27 +/- 18)/h to (15 +/- 9)/h. The ESS and SL indicated that subjective and objective sleepiness improved. CONCLUSIONS: Microarousals with at least 3 seconds EEG changes can be scored by computerized EEG analysis. MAI can reflect the severity of daytime sleepiness. MAI is complementary to AHI in the diagnosis and treatment of SAHS. After nCPAP, the patients' MAIs decreased and daytime sleepiness improved.

Adult↗

PubMed2001

[Modeling of feeling institution in pilot structural model].

Objective. To improve a structural pilot model proposed by R. A. Hess, in which element of observation feeling institution was neglected. Method. Real simulation results showed that there was a blind region for small observation signal, and pilot made no response in this region. So we knew that the basic characteristics of the observation feeling institution were observation threshold and observation noise. A Neural Network (NN) receptor model was augmented in the structural pilot model to describe the characteristics of human observation feeling institution. Furthermore, using the augmented model, the affection of the pilot model on the characteristics of the closed-loop system of pilot and controlled element was studied. Result. The affection of NN perception on the closed-loop system was that the stable gain region of the human pilot was extended. Conclusion. The proposed model was reasonable for the element of human feeling institution.

Aerospace Medicine↗

PubMed2001

[The effect of viper venom on the attachment, migration and proliferation of Tenon's capsular fibroblasts].

OBJECTIVES: To observe the effect of viper (Ahylysantipfarciasi) venom on attachment to collagen, migration and proliferation of rabbit Tenon's capsular fibroblast (TFs) in tissue culture. METHODS: Anti-adhesion experiment: The 3 -- 5 passage TFs suspended in DMEM medium were pre-incubated for 30 minutes in the presence of various concentrations of viper venom (0, 2.5 x 10(-4), 5.0 x 10(-4), 1.0 x 10(-3) and 5.0 x 10(-3) U/ml) at 37C, 5% CO(2), then inoculated in 24-well plate coated with rat-tail collagen. After incubation for 90 minutes, the floating cells were removed. The attached cells in each well were enumerated microscopically and determined by the value of absorption (A) of 3-(4, 5-dimethylthiazolzyl)-2, 5-diphenyl tetrazodium bromide (MTT). Anti-migration experiment: A denuded area was made when the 3rd passage of TFs was confluent into a monolayer. Cells were then exposed to viper venom (0 -- 5.0 x 10(-3) U/ml) at 37C, 5% CO(2), and the cells having migrated into the denuded area were enumerated every 6 hours. Anti-proliferative experiment: Two hours after the 3rd passage of TFs was incubated in the 24-well plate at 37C, 5% CO(2), they were exposed to different concentrations of viper venom drug (0 -- 5.0 x 10(-3) U/ml). Twenty-four and 48 hours later, the number of cells was determined by MTT method. RESULTS: Viper venom inhibited TFs from attaching to collagen in a dose-dependent manner and the ID(50) was 1.0 x 10(-3) U/ml. Only did 5.0 x 10(-3) U/ml of viper venom show significant difference from the control during 6 -- 48 hours. The difference of A value was not significant among all groups at 24 and 48 hr. CONCLUSIONS: In vitro, viper venom (> 1.0 x 10(-3) U/ml) can significantly inhibit the attachment of TFs to collagen, and 5.0 x 10(-3) U/ml can inhibit the migration, but can not affect their proliferation.

Animals↗

PubMed2001

[Analysis of genetic diversity of Bama miniature pigs and Guizhou miniature pigs by RAPD].

RAPD analysis was performed with 31 selected single primers to study genetic diversity of two strains of miniature pigs, The percentages of polymorphisic loic in or between two strains of miniature pigs were 30.9%, 29.2% and 25.7% respectively, and the average genetic distances in and between two strains of miniature pigs were 0.120, 0.072, and 0.067 respectively. These results suggested that genetic diversity and genetic variability were poorer in and between two strains of miniature pigs than ordinary breeds' pigs.

Animals↗

PubMed2001

Dexamethasone modulation on cultured human retinal pigment epithelial cell.

PURPOSE: Dexamethasone(DEX) was tested for its ability to modulate human retinal pigment epithelium(hRPE) cell proliferation in cell culture. METHODS: DEX in different concentrations was added to cultured hRPE cells. The effects were measured with MTT method, 3H-thymidine(3H-TdR) incorporation and flow cytometry. RESULTS: DEX increased survival rate and DNA synthesis from 32 mg/L to 320 mg/L under hRPE culture conditions, but paradoxically reduced them at 1,000 mg/L and 3,200 mg/L in dose and time dependent fashion by both MTT assay and 3H-TdR incorporation. The cell numbers in S phase and G2/M phase increased 28.32% at DEX concentration 320 mg/L, in contrast, reduced 41.84% at 1,000 mg/L. CONCLUSION: DEX increased proliferation from 32 mg/L to 320 mg/L, and inhibited proliferation at concentrations greater than 320 mg/L. The inhibiting effect of DEX may happen in s phase and G2/M phase.

Anti-Inflammatory Agents↗

PubMed2001

[Clinical significance of antibiotic prophylaxis for transrectal prostate biopsy].

OBJECTIVE: To evaluate the efficacy and safety of single-dose oral antibiotic prophylaxis in the METHODS: Between prevention of post-procedure infections in patients undergoing transrectal prostate biopsy. September 1998 and March 2001, a total of 192 patients who had an abnormal digital rectal examination and/or prostate specific antigen 4 ng/ml or greater underwent transrectal ultrasound guided systematic 13 cores prostate biopsy. The patients were randomly divided into three groups. Group A (62) received a placebo (Vit C) tablet twice a day for 3 days, group B (64) a single dose of ciprofloxacin (0.5 g) and metronidazole (0.4 g), and group C (66) the same combination twice a day for 3 days. Urine cultures were obtained 48 h after the biopsy and blood cultures when patients who developed fever. RESULTS: Noninfective complications included were rectal bleeding, haematuria and pain. Infective complications included urinary tract infection and fever. There was no significant difference among the three groups in noninfective complications but the incidence of infective complications in group A was significantly higher than in groups B and C (P < 0.01). There was no significant difference among group B and C in infective complications (P > 0.05). CONCLUSIONS: Our study shows single-dose oral antibiotic prophylaxis is effective and safe to prevent infectious complications follow transrectal prostate biopsy.

Aged↗

PubMed2000

Stimulation of the mitogen-activated protein kinase cascade and tyrosine phosphorylation of the epidermal growth factor receptor by hepatopoietin.

Hepatopoietin (HPO) is a novel human hepatotrophic growth factor, which specifically stimulates proliferation of cultured primary hepatocytes in vitro and liver regeneration after liver partial hepatectomy in vivo. Recently, the identification of the mitogenic effect of HPO on hepatoma cell lines and the existence of HPO-specific receptors indicate that HPO acts via its specific cell surface receptor. However, the molecular mechanism of HPO action is not fully elucidated. In this report, we examined the signal transduction events induced by HPO in hepatoma cell line (HepG2). Our results demonstrated that HPO induces phosphorylation of mitogen-activated protein kinase kinase and mitogen-activated protein kinase (MAPK) in a rapid and transient manner. HPO stimulates tyrosine phosphorylation of epidermal growth factor receptor (EGFR). Furthermore, we observed that both MAPK activation and the mitogenic effect of HPO on HepG2 cells were completely blocked by AG1478, a specific inhibitor of EGFR tyrosine kinase activity. However, the effects of HPO were not antagonized by an EGFR-blocking antibody, mAb528, which blocks the interaction between epidermal growth factor and EGFR, indicating that stimulation of tyrosine phosphorylation of EGFR by HPO was not mediated by epidermal growth factor. In contrast, genistein, a general tyrosine kinase inhibitor, significantly attenuated the tyrosine phosphorylation of EGFR in response to HPO. In conclusion, our results suggest that tyrosine phosphorylation of EGFR may play a critical role in MAPK activation and mitogenic stimulation by HPO.

Enzyme Inhibitors↗

PubMed2000

Identification and characterization of differentially expressed genes in the early response phase during liver regeneration.

It has been suggested that the early response was a critical regulator of the remaining quiescent liver cells reentering the cell cycle after partial hepatectomy. The identification of genetic factors and function important in the early response phase during liver regeneration after partial hepatectomy will help in understanding the underlying molecular mechanisms of hepatic injuries. Through the application of complementary DNA representational difference analysis (RDA), we have identified genes that are up-regulated in early response phase during liver regeneration. Results from slot blot and Northern blot analysis confirmed that the RDA products were truly differentially expressed. In addition to well-characterized up-regulated genes during liver regeneration, including IGFBP-1, LRF-1, and metallothionein, we demonstrate the differential expression of at least 6 genes previously not known to be associated with liver regeneration. PC3 and TEC genes were identified as immediate-early response genes and were dramatically increased following partial hepatectomy. Ribosomal protein L6, ribosomal protein S7, chaperonin 10, and cytochrome oxidase I were identified to be up-regulated 4- to 5-fold after 70% partial hepatectomy. In addition to the known genes, 7 novel genes were isolated. Among them, two genes showed their up-regulation in liver regeneration by Northern blot analysis. One was exclusively expressed in liver, and no expression was observed in other tissues. Peak expression, 30-fold above baseline, occurred 60 min after 70% hepatectomy. Cycloheximide pretreatment could not suppress the induction of this gene, indicating that this gene as a novel immediate-early response gene following partial hepatectomy. The novel gene, which was represented three times in the differential clones, may be one of the highly up-expressed genes in regenerating liver. Its transcript is undetectable in normal liver; its level of mRNA increased by 0.5 h after 2/3 partial hepatectomy, reaching a maximum at 2 h. This gene is similar to human alpha-1-beta-glycoprotein (40%). These results suggest a role of these genes in the early response phase of liver regeneration.

Animals↗