Biomedical subjects

Li Xu

Publications and source records attributed to Li Xu.

At least 91 records · Page 5Linked to original sources

PubMed2005

[Prophylaxis and clinical treatment for surgical margin recurrence of small primary hepatocellular carcinoma].

BACKGROUND & OBJECTIVE: Along with the advance of medical technology and instruments, many patients with small primary hepatocellular carcinoma (HCC) had been found, who are mainly treated with surgical resection with high postoperative recurrence rate of over 60%. This study was to explore prophylaxis and clinical treatment for these patients to reduce postoperative recurrence rate. METHODS: Clinicopathologic data of 283 patients with small HCC, treated in Central Hospital of Kaiping and Cancer Center of Sun Yat-sen University from 1991 through May 2003, were analyzed. Over 85% patients suffered cirrhosis with liver reserve dysfunction, and were mainly treated with irregular hepatectomy. Of the 283 patients, 140 received application of anhydrous alcohol injection or alcohol-soaked gelatin sponge on surgical margin (test group), 143 received no application of alcohol on surgical margin (control group). The 2 groups were comparable in age, gender, tumor location, clinical stage, and Child-Pugh stage. RESULTS: The 1-year surgical margin recurrence rate was significantly higher in test group than in control group (21.4% vs. 4.4%, P0.05). Intrahepatic metastasis or recurrence rate, 5-year overall survival rate, and tumor-free survival rate were not different between the 2 groups. Both groups had no severe complications. CONCLUSIONS: Application of anhydrous alcohol on surgical margin or anhydrous alcohol injection in remnant liver after irregular hepatectomy may benefit to reduce postoperative recurrence in surgical margin for small PLC, but has no impact on intrahepatic metastases and recurrence in remnant liver.

Carcinoma, Hepatocellular↗

PubMed2005

[Isobaric and hyperbaric local anesthetic used in spinal anesthesia].

OBJECTIVE: To reveal the advantages and disadvantages of the application of isobaric and hyperbaric local anesthetic in spinal anesthesia so as to provide reference for clinical practice. METHODS: One hundred and sixty ASA patients (physical status I - II) undergoing lower abdominal surgery within 3 hours under spinal anesthesia (using CSEA technique via spinal needle in epidural needle) were allocated to 2 groups with 80 cases each. In lateral decubitus, patients randomly received a subarachnoid injection of 3.0 mL (15 mg) isobaric (Group I) or hyperbaric (Group H) bupivacaine and then turned supine. Hemodynamic changes and patients' responses were perioperatively observed. After subarachnoid injection, we recorded the time of onset and motor block, the peak sensory blocked level, the time of regression of 2 dermatomes, the time of the first administration of analgesics for a significant pain of the incision, the time of the regression of motor block to modified Bromage scale 2, and the time of recuperating the function of urination. RESULTS: Both isobaric and hyperbaric 0.5% bupivacaine solutions in a volume of 3.0 mL provided effective sensory and motor block for the operations. The time of onset and complete motor block were similar in the two groups. Compared with Group I, the time of peak sensory block in Group H was shorter, the peak sensory block level was higher (more maximal dermatomes of blocked sensory nerves), the time of regression of sensory and motor block were shorter, the time of recuperating the function of urination was longer, and the incidence of feeling sick, nausea, vomiting and hypotension was higher. CONCLUSION: Isobaric solution is superior to hyperbaric solution in spinal anesthesia.

Aged↗

PubMed2005

Co-expression of the complement regulatory proteins human DAF and CD59 with an IRES-mediated dicistronic mammalian vector enhances their cell protective effects.

The human complement regulatory proteins (hCRPs) decay accelerating factor (DAF/CD55) and protectin CD59 transfected into non-human cells could confer protection against human complement. The combination of DAF and CD59 would be an effective strategy to help overcome host complement-induced hyperacute rejection in xenotransplantation. We constructed a dicistronic mammalian expression vector pcDNA3-CD59IRESDAF by using the internal ribosomal entry sites (IRES) of the encephalomyocarditis virus (EMCV). RT-PCR, Western blotting and immunofluorescence microscopic analysis demonstrated that the EMCV IRES allowed for efficient co-expression of hCD59 and hDAF on the surface of NIH/3T3 cells transfected stably with pcDNA3-CD59IRESDAF. Human complement-mediated cytolysis assays showed that co-expressed DAF and CD59 proteins could provide more significant protection against complement-mediated cytolysis than either hCD59 or hDAF alone. These results suggest that IRES containing polycistronic vector should improve the efficiency and effectiveness of multi-gene delivery and that the construct pcDNA3-CD59IRESDAF vector has potential therapeutic value for effectively controlling complement activation and for preventing hyperacute rejection in clinical gene therapy.

Animals↗

PubMed2005

[Genetic polymorphism of D6S477, D9S1118, D18S865, D19S400, and D20S161 short tandem repeat loci in Qingdao Han population].

OBJECTIVE: To illuminate the preliminary genotype and allele frequency distribution of D6S477 and the other four short tandem repeat(STR) loci in Chinese Han population in Qingdao area and to probe the possibility of their genetic application. METHODS: Two hundred ACD-blood specimens were collected from the unrelated individuals in Qingdao. The DNA samples were extracted with Chelex method and were amplified by polymerase chain reaction technique. The PCR products were analyzed by polyacrylamide gel electrophoresis and displayed using silver staining. RESULTS: The authors obtained the allele frequency distribution and preliminary genotype of D6S477, D9S1118, D18S865, D19S400 and D20S161 STR loci. No deviation from Hardy-Weinberg equilibrium was observed in the five loci. CONCLUSION: All the five loci have higher chance of exclusion and discriminating power, and they will be useful markers for researches in genetics.

Asian People↗

PubMed2005

[Interleukin-1 polymorphisms in patients with aggressive periodontitis].

PURPOSE: To study whether interleukin-1 (IL-1) genotypes and/or alleles were associated with aggressive periodontitis (AgP). METHODS: Anti-coagulated peripheral blood samples were obtained from 122 AgP patients and 95 healthy controls. Genomic DNA was extracted from each sample. Single nucleotide polymorphisms (SNPs) at IL-1A +4845 and IL-1B +3954 were analyzed by standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The polymorphism of a variable number tandem repeat (VNTR) in intron 2 of IL-1RN was detected by PCR amplification and fragment size analysis. The genotypes and/or alleles distribution differences between two groups were analyzed by logistic regression analysis. RESULTS: The frequencies of A2+ genotype and allele 2 at IL-1A +4845 were significantly increased in male AgP patients compared with male controls (genotype: 18.0% vs 4.3%, adjusted OR=5.58, 95% CI=1.09-28.68, P=0.039; allele: 9.0% vs 2.2%, adjusted OR=4.97, 95% CI=1.01-24.50, P=0.049). CONCLUSIONS: The IL-1A +4845 polymorphism may be associated with AgP susceptibility in Chinese males.

Aggressive Periodontitis↗

PubMed2005

[Experimental study of the total flavonoid in Hypericum perforatum on depression].

OBJECTIVE: To investigate pharmacological effects of the total flavonoid in Hypericum perforatum on depression. METHOD: Experimental depression was induced by subcutaneous injection of reserpine in mice. The concentration of monoamine transmitters including 5-HT and NE, the activity of monoamine oxidase (MAO) in brain and reserpine-induced symptoms of depression, such as ptosis, attenuation of autonomous activity, behavioral despair, acquired helplessness and sleep, were measured respectively to evaluate the effects of the total flavonoid in H. perforatum on the depression. RESULT: The total flavonoid in H. perforatum significantly decreased the activity of MAO, inhibited the ptosis and the attenuation of autonomous behavior induced by reserpine respectively. The levels of 5-HT and NE were also attenuated by the total flavonoid in H. perforatum remarkably. In addition, the total flavonoid in H. perforatum was shown to inhibit behavioral despair and acquired helplessness and to prolong the sleep time in the mice. Following the treatment with the total flavonoid in H. perforatum, 5-THP, at the dosage without any side-effects, caused the tremble in the mice. CONCLUSION: The results indicate that total flavonoid in H. perforatum can significantly inhibit the depression.

Animals↗

PubMed2005

[Induction of nicotinic acid hydroxylase activity of Pseudomonas putida NA-1 and optimization of transformation conditions].

Some features of Pseudomonas putida NA-1 strain in cultivation and enzyme production were different from S. marcescens IFO 12648 and P. fluorescens TN5 stains which could transform nicotinic acid to 6-hydroxynicotinic acid reported by other scientists, such as optimal carbon and its optimal concentration, optimal inducer concentration, and optimal cultivation temperature. The ideal transformation condition was nicotinic acid 3%, temperature 35 degrees C and pH 7.0. Under an appropriate condition, in a 4 liter fermenter, production yield of 6-hydroxynicotinic acid by Pseudomonas putida NA-1 was 108.39 g/L.

Biotransformation↗

PubMed2005

[Studies on extracellular virulent factors produced by potential pathogenic bacteria isolated from abalone postlarvae and biofilms].

To find out the potential pathogen(s) that caused massive death of abalone postlarvae( Haliotis diversicolor supertesta ) in Southern China, 105 bacterial strains were isolated from the water, whitened postlarvae and their biofilms of an abalone farm in Guangdong Province. Extra-cellular protease, gelatinase, lipase as well as haemolysis tests were performed on them. Lysophospholipase (Tlh)-targeted PCR was also carried out in order to reveal if the haemolysis caused by bacterial strains were related to Tlh. Results showed that 35 out of 105 strains possessed extra-cellular enzymatic abilities and strains 1, 2, 3, 5, 9 and 16 were the most powerful ones of all. Among these 35 strains, 85.6% strains (30/35) possessed haemolytic activities on goat blood agar and specific PCR revealed that 16 strains were PCR positive, indicating that they contained Tlh genes. In order to identify these strains, API 20 E strips were employed and results indicated that 50% were vibrios, among them Vibrio alginolyticus composed 70% of the vibrio population. In conclusion, compared to other strains, 6 Vibrio alginolyticus (strain 1, 2, 3, 5, 13, and 16 ) and 2 Vibrio parahaemolyticus (strain 9 and 21) which all were isolated from whitened abalone postlarvae, warrant further studies due to their better abilities in extra-cellular enzyme(s) production and/or haemolytic activities.

Animals↗

PubMed2005

[The effect of the photoelectric detector on the accuracy of the spectrometer].

An optimized photoelectric detector will increase the precision of a spectrometer, thus indicates an important way to develop high performance spectrometer. With an eye to this, a model describing the process that spectrogram is integrated and sampled by photoelectric detector and restored after low-pass filtering is developed. Based on the model, the influence of the characteristic parameters of the detector on the spectral line in the frequency domain is analyzed and the relation between the full width half maximum (FWHM) of the spectra line and the integral interval, sampling space and sensitivity of the detector is deduced. The conclusion indicates that both the integral interval and sampling space should be 1/6 of the FWHM for a spectral line with gaussian profile as a result of compromise between accuracy and feasibility. Moreover, the critical point deciding the right situation for scanner and array detector is given. Other guide line to optimize the photoelectric detector and increase accuracy is suggested also.

Algorithms↗

PubMed2005

Forced-air warming and fluid warming minimize core hypothermia during abdominal surgery.

OBJECTIVE: To evaluate the effect of intraoperative combined forced-air warming and fluid warming system on patient's core temperature, blood loss, transfusion demand, extubation time, and incidence of postoperative shivering. METHODS: Forty patients with American Society of Anesthesiologists physical status I and II, aged 18-70 years, scheduled for elective abdominal surgery were randomly assigned to receive intraoperative warming from a forced-air blanket and fluid warming system or conventional cotton blanket, 20 in each group. The core temperature was recorded every 20 minutes during the operation, as well as the blood loss, blood transfusion, extubation time, and incidence of postoperative shivering. RESULTS: The core temperature at the end of the surgery in the warming group was significantly different from that in the control group (36.4 +/- 0.4 degrees C vs. 35.3 +/- 0.5 degrees C, P < 0.001). Application of intraoperative warming significantly shortened the time between the end of the surgery and extubation (P < 0.01). Postoperative shivering occurred in 30% of the patients in the control group compared to no patient in the warming group (P < 0.01). CONCLUSION: Active warming with air-forced blanket and fluid warming system provides sufficient heat to prevent hypothermia during abdominal surgery.

Abdomen↗

PubMed2005

[The safety and efficacy of Cypher drug-eluting stent: results from a six months follow-up study in patients with ST-segment elevation myocardial infarction].

OBJECTIVE: To investigate the feasibility, safety and efficacy of Cypher drug-eluting stent implanted after the emergency percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: From Nov. 2002 to Dec. 2004, 186 patients with STEMI treated by emergency PCI were included into this study. The incidence of major adverse cardiovascular event (MACE), stent thrombosis and restenosis were evaluated during 6 months follow-up after PCI. RESULTS: One hundred and sixty-eight patients were successfully treated by emergency PCI and there were no complication during the procedure. The rates of successful treatment were 100%. One hundred and seventy-five Cypher drug-eluting stents were successfully implanted into 171 target lesions. There was one case with acute stent thrombosis among 186 patients, and the MACE and mortality were 2.4% and 1.8%, respectively, during the first one month follow up. Six months later, the MACE was 4.2% and the mortality was 2.4%. The in-stent thrombosis and restenosis rates were 1.2% and 1.8%, respectively, when evaluated by angiography and clinic follow up at six months after PCI. CONCLUSION: Implanting a Cypher drug-eluting stent in STEMI patients during emergency PCI is as safe and effective as a conventional bare stent. Cypher drug-eluting stent can reduce restenosis rate and MACE in STEMI patients treated with emergency PCI.

Adult↗

PubMed2004

Chemo-enzymatic synthesis of tripeptide RGD diamide in organic solvents.

The tripeptide BzArgGlyAsp(NH(2))(2) was synthesized by a combination of chemical and enzymatic methods in this study. First of all, GlyAsp(NH(2))(2) was synthesized by a novel chemical method in three steps including chloroacetylation of L-aspartic acid, esterification of chloroacetyl L-aspartic acid and ammonolysis of chloroacetyl L-aspartic acid diethyl ester. Secondly, kinetically controlled synthesis of BzArgGlyAsp(NH(2))(2) catalyzed by trypsin in organic solvent was conducted. The optimum conditions are pH 8.0, 30 degrees C in ethanol/Tris-HCl buffer system (85:15, v/v) for 80 min in the maximum yield of 74.4%.

Amides↗

PubMed2004

Analgesic effect of extracts of Chinese medicinal herbs Moutan cortex and Coicis semen on neuropathic pain in mice.

Neuropathic pain arising from peripheral nerve injury is a clinical disorder characterized by a combination of spontaneous pain, hyperalgesia and tactile pain (allodynia), and remains a significant clinical problem since it is often poorly relieved by conventional analgesics. To seek an analgesic compound(s) in Chinese herbs, we examined the effect of seven Chinese herbs that are routinely prescribed for pain management in two neuropathic pain models: allodynia induced by intrathecal administration of prostaglandin F2alpha (PGF2alpha) and by selective L5 spinal nerve transection. The extracts of Moutan cortex and Coicis semen dose-dependently alleviated the PGF2alpha-induced allodynia by oral administration 1 h before intrathecal injection of PGF2alpha. When orally administrated every day for 7 days, these extracts attenuated neuropathic pain in the ipsilateral side, but not in the contralateral side, day 7 after L5 spinal nerve transection. The increase in NADPH diaphorase activity in the spinal cord associated with neuropathic pain was also blocked by these extracts. These results suggest that Moutan cortex and Coicis semen contain substances effective in neuropathic pain.

Anesthesia↗

PubMed2004

Radiocarbon apportionment of fossil versus biofuel combustion sources of polycyclic aromatic hydrocarbons in the Stockholm metropolitan area.

Source-diagnostic markers and the isotopic composition of polycyclic aromatic hydrocarbons (PAHs) were examined in surface sediments from the greater Stockholm waterways to deduce the contribution from biomass sources to the environmental PAH load. The summed concentration of 20 PAHs ranged from 0.8 to 45.1 microg/g (dry weight) and exhibited a steep decline with increasing distance from the city center evidencing that sources within the metropolitan area of Stockholm dominate its PAH burden. Several diagnostic PAH ratios indicated an overwhelming predominance of pyrogenic sources over the petrogenic ones, while retene and 1,7-dimethylphenanthrene were unable to correctly evaluate the contribution from biomass combustion. The stable carbon isotope composition (delta13C) of individual PAHs ranged from -24.8 to -27.0% but also was proved inefficient to discriminate between different types of fuels due to the overlapping signals in various sources. The delta14C values of PAHs ranged between -550.4 and -934.1%, indicating a clear predominance of fossil fuel sources. By using an isotopic mass balance approach, we estimated that on average 17+/-9% of PAHs derived from biomass combustion. This radiocarbon apportionment, in conjunction with detailed energy statistics for the Stockholm region, revealed that the ambient PAH burden is roughly similar, per unit energy produced, from fossil fuels and biofuels. Societies' shifting energy policies toward a larger reliance on biofuels may thus not lead to further deterioration of air quality and respiratory ailments for the urban population.

Bioelectric Energy Sources↗

PubMed2004

Across-site threshold variation in cochlear implants: relation to speech recognition.

Functional implications of across-site variation in detection thresholds in subjects with cochlear implants were evaluated by comparing thresholds to speech recognition performance. Detection thresholds for bipolar (BP) and monopolar (MP) stimulation of all available stimulation sites were assessed in 21 subjects with Nucleus CI24M and CI24R(CS) implants. We found significant negative correlations between speech recognition and within-subject across-site threshold variance for both BP and MP stimulation, but no significant correlation of speech recognition with mean threshold levels. These results suggest that across-site variance of detection thresholds could provide a useful early indication of the prognosis for speech recognition and might serve as an indicator for specific therapeutic approaches in individual subjects.

Adult↗

PubMed2004

[The effect of intraoperative warming on patient core temperature].

OBJECTIVE: To investigate the influence of using fluid warming and forced-air warming system on patient core temperature, blood loss, blood transfusion, extubation time, and postoperative shivering. METHODS: Forty ASA (American Society of Anesthesiologists' Physical Status) I-II patients, aged 21-69 years, scheduled for elective abdominal surgery under general anesthesia, were enrolled in the study. The patients were premedicated with intramuscular dolantin 50 mg and atropine 0.5 mg. Anesthesia was induced with midazolam 1 mg, fentanyl 50-100 microg and propofol 1.5-2.0 mg/kg. Tracheal intubation was facilitated with vecuronium 1mg and succinylcholine 1.5-2.0 mg/kg. The patients were mechanically ventilated and anesthesia was maintained with isoflurane 1.5-2.0%, 50% N2O in oxygen and intermittent iv boluses of fentanyl (total dose 5-6 microg/kg). Vecuronium was used for muscle relaxation during maintenance of anesthesia. The patients were randomly divided into 2 groups: control group (n = 20) and warming group (n = 20). In both groups, the patients were covered with surgery blanket. In the warming group, patients were additionally warmed with fluid warming device and forced-air warming system during the operation. The core temperature was recorded every 20 minutes during the operation, as well as the blood loss, blood transfusion, extubation time and postoperative shivering. RESULTS: The core temperature at the end of the surgery was (36.4 +/- 0.4) degrees C in the warming group and (35.3 +/- 0.5) degrees C in the control group. The difference was statistically significant (t = 7.547, P < 0.001). There was no significant difference of blood loss and blood transfusion between two groups. The extubation time was significantly shorter in the warming group [(18 +/- 6) vs (26 +/- 10) min, t = -3.364, P = 0.002]. 6 patients shivered postoperatively in the control group and none in the warming group (chi2 = 7.059, P = 0.008). CONCLUSION: Fluid warming system and forced-air warming system can effectively maintain normothermia during the surgery and then help to reduce the extubation time and postoperative shivering.

Abdomen↗

PubMed2004

Identification of a functional variant of estrogen receptor beta in an African population.

In this study, we identified five novel polymorphisms in the estrogen receptor beta (ERbeta) gene in an African population. Interestingly, two of these variants are expected to change the amino acid sequence of the ERbeta protein. These changes correspond to an isoleucine to valine substitution at amino acid position 3 (I3V) and a valine to glycine substitution at position 320 (V320G), respectively. The functional consequences of these amino acid substitutions were determined in different in vitro assays. The I3V mutation displayed no differences with regard to transcriptional activity in a reporter assay, as compared with the wild-type receptor. The V320G mutation, however, showed significantly decreased maximal transcriptional activity in a reporter assay, although its binding affinity for 17beta-estradiol was not affected. A pull-down assay indicated that the interaction of full-length TIF2 with hERbetaV320G was weaker than with hERbetawt. Moreover, surface plasmon resonance analysis revealed reduced interaction of the V320G ERbeta variant with the NR box I and II modules of TIF2. To our knowledge, this represents the first identification of a functional polymorphism in the ERbeta gene. This novel polymorphism provides a tool for human genetic studies of diseases in the African population.

Amino Acid Sequence↗

PubMed2004

Abrupt tropical vegetation response to rapid climate changes.

Identifying leads and lags between high- and low-latitude abrupt climate shifts is needed to understand where and how such events were triggered. Vascular plant biomarkers preserved in Cariaco basin sediments reveal rapid vegetation changes in northern South America during the last deglaciation, 15,000 to 10,000 years ago. Comparing the biomarker records to climate proxies from the same sediment core provides a precise measure of the relative timing of changes in different regions. Abrupt deglacial climate shifts in tropical and high-latitude North Atlantic regions were synchronous, whereas changes in tropical vegetation consistently lagged climate shifts by several decades.

Atmosphere↗