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Biomedical subjects

Lei Wang

Publications and source records attributed to Lei Wang.

At least 343 records · Page 19Linked to original sources
PubMed2004

Spectrofluorimetric determination of trace amounts of europium(III) ion with lutetium(III)-sparfloxacin-sodium dodecyl sulfate luminescence enhancement system.

A new luminescence-enhancement system based on complex formation between europium and sparfloxacin in the presence of lutetium in a sodium dodecyl sulfate solution has been discovered. By adding a suitable amount of Lu3+ to the Eu-sparfloxacin-sodium dodecyl sulfate system, the luminescence can be enhanced by approximately 5-fold compared with that of the system without Lu3+. Under the optimum conditions, the luminescence intensity of the system is a linear function of the concentration of europium in the range of 1.0 x 10(-10) - 5.0 x 10(-7) mol L(-1). The detection limit of europium is 2.0 x 10(-13) mol L(-1) (S/N = 3). The system was used for the determination of trace amounts of europium in rare earth samples with satisfactory results.

Journal Article↗
PubMed2004

[A study of the dynamic relationship between AVP mRNA expression in PVN and immuno-responsiveness in rats].

OBJECTIVE: To investigate the proper dynamic relationship between AVP mRNA expression in PVN and immune response. METHODS: Through the establishment of the immuno-enhancement and immunosuppression rat models, the in situ hybridization histochemical methods and the images analytical techniques were used to detect the dynamic variations of AVP mRNA content of PVN during different periods of immune response. RESULTS: 1. The average area of AVP mRNA positive signal in single cell of PVN in the immune suppression group was significantly smaller than that in the immune enhancement group and control group (P < 0.05). 2. The average gray degree of AVP mRNA positive signal in single cell of PVN in the maximum period of immune response was lower than that in the incipient enhancement period of immune response (P < 0.05). On the other hand, the average gray degree was clearly higher in the minimum period of immune response than that in the incipient suppression period of immune response (P < 0.05). 3. The total area that the AVP mRNA-positive signal occupied in the whole PVN in the maximum enhancement period of immune response was significantly larger than that in the incipient enhancement period response and the control group (P < 0.05). Conversely, it was evidently smaller in the minimum suppression period than in the incipient suppression period of immune response (P < 0.05). 4. The average gray degree of AVP mRNA positive signal in the whole PVN in the maximum enhancement period of immune response was significantly lower than that in the incipient enhancement period and the control group (P < 0.05). In turn, it was obviously higher in the minimum suppression period than in the incipient suppression period of immune response and the control group (P < 0.05). CONCLUSION: There is a positive relationship between the AVP mRNA content of PVN and the intensity of immune responsiveness, indicating that the situation of AVP gene transcription varies with the variation of immune responsiveness.

Animals↗
PubMed2004

[Early prediction of efficaciousness after first course of chemotherapy in de novo acute leukemia].

To achieve the complete remission (CR), acute leukemia (AL) patient must get through the period of myeloid ablation after chemotherapy that the white blood cell (WBC) count in peripheral blood decreases rapidly. To observe the relationship of WBC count with therapeutic effectiveness after chemotherapy in previously untreated AL, eighty cases of previously untreated acute leukemia who took the first induction chemotherapy course were analyzed. Blood routine was carried out 2 to 3 times every week while the bone marrow pictures on 12th and 20th day after chemotherapy were observed. 80 patients were divided into 3 groups based on the lowest value of WBC count after chemotherapy: 0.9 x 10(9)/L group. The results showed that the complete remission rates after the first course of chemotherapy were 60 vs 55.6 vs 27.3% respectively in the three groups which WBC counts were 0.9 x 10(9)/L. The total efficaciousness rates were 90 vs 92.6 vs 66.7 respectively in the three groups. The efficaciousness rate of the first two groups significantly differed from the third group (P < 0.01). However, no significant difference was shown between the first and second groups. It is concluded that the leukocyte count after the first course of chemotherapy may be an early indicator to predict the efficaciousness of chemotherapy.

Acute Disease↗
PubMed2004

[Effects of a novel recombinant polypeptide from the sea anemone Anthopleura sp. on left ventricular function in New Zealand rabbits with chronic congestive heart failure].

OBJECTIVE: To observe the effects of recombinant hk2a, a novel neurotoxin from the sea anemone Anthopleura sp. on the left ventricular function in New Zealand rabbits with chronic congestive heart failure(CCHF). METHODS: CHF model was established using New Zealand rabbits by abdominal aortic coarctation. The left ventricular ejection fraction (LVEF) was measured by Acuson ultrasound systems (Sequoia 512) at 0, 5, 15, 30, 45 and 60 min respectively after intravenous injection with a single dose of recombinant hk2a (20 microg/kg x b x w.). The response of the rabbits to hk2a treatment was observed in comparison with that of the control group. RESULTS: Recombinant hk2a immediately and significantly increased the left ventricular ejection fraction of the rabbit models of CCHF after intravenous injection (P<0.05), and its effects were maintained for more than 1 h without affecting the heart rate. CONCLUSION: recombinant hk2a significantly increases the left ventricular ejection fraction in New Zealand rabbits with CCHF.

Animals↗
PubMed2004

The supraorbital keyhole approach with eyebrow incisions for treating lesions in the anterior fossa and sellar region.

BACKGROUND: Keyhole surgery has developed since the 1990s as a less invasive therapeutic strategy for intracranial lesions, initially for the treatment of intracranial aneurysms. The purpose of this study was to describe and evaluate the results of surgical treatment of lesions in the anterior fossa and sellar region via a supraorbital keyhole approach using eyebrow incisions. METHODS: Between April 1994 and July 2003, 54 patients with lesions in the anterior fossa and sellar region were operated on via the supraorbital keyhole approach. The surgical results were studied retrospectively and compared with that of patients with lesions at the same locations but treated via a conventional subfrontal approach. RESULTS: No significant difference in curative effect was found between the conventional subfrontal approach and the supraorbital keyhole approach. However, the supraorbital approach required a much smaller skin incision, causing less surgical trauma, while achieving excellent surgical exposure and good recovery. CONCLUSION: The supraorbital keyhole approach using an eyebrow incision is safe, effective, and both suitable and convenient for treating lesions in the anterior fossa and sellar region, with almost no adverse consequences on the facial features of patients.

Adolescent↗
PubMed2004

[Study of the effect of the low dosage endotoxin damage on the expression of the organic cation transporter (OCT1) mRNA in hepatocytes].

OBJECTIVE: To elucidate the effect of the low dosage endotoxin damage on the expression of the organic cation transporter 1 (OCT1) mRNA in hepatocytes and make an approach to the probable effect of dexamethasone on the expression of the OCT1 mRNA after endotoxin damage. METHODS: (1) The endotoxin damage model was established in rats; (2) The change of the expression of OCT1 mRNA in hepatocytes after endotoxin damage was observed by in situ hybridization method; (3) The change of the ultra structure of hepatocytes after endotoxin damage was observed with the electron microscope; (4) Dexamethasone was injected intraperitoneally before endotoxin damage in order to determine the influence of dexamethasone on the expression of OCT1 mRNA after endotoxin treatment. RESULTS: The expression of OCT1 mRNA decreased until 16 hours (0.5745+/-0.012, P<0.01) after endotoxin treatment and then increased after this time point, which was still lower than the normal control; The expression of OCT1 mRNA in rat hepatocytes increased at each time point after endotoxin damage with dexamethasone treatment. It was highest at 16 hours (0.6327+/-0.007, P<0.01) after endotoxin damage, but it was still lower than that of the normal control. CONCLUSION: Endotoxin could repress the expression of OCT1 mRNA even before the low dosage endotoxin inducing serious damage to the structure of hepatocytes; Dexamethasone could not induce the expression of OCT1 mRNA in normal hepatocytes, but could lighten the repression of endotoxin on the expression of OCT1 mRNA. And then the expression of OCT1 mRNA could increase at some extent after endotoxin damage with dexamethasone treatment.

Animals↗
PubMed2004

[Effects of aminoguanidine in different dosages on renal function in endotoxin induced rabbits shock model].

OBJECTIVES: To explore the effects of aminoguanidine (AG) in different dosages on renal function in endotoxin induced rabbits shock model in the early stage and to approve the effects of dose-depended and time-depended of AG. METHODS: Fourty New Zealand rabbits under anaesthesia were randomly divided into 5 groups: sham group, LPS group, the first group of AG, the second group of AG, the third group of AG. Each rabbits from the four groups received Escherichia Coli O55B5 LPS 400 micro g/kg to induce endotoxic shock except sham group. Edotoxic shock was diagnosed when the mean arterial pressure (MAP) decreased to 30%. Each rabbits in sham group and LPS group received 5ml NS, in the other three groups were infused with AG 30 mg/kg (the first group of AG), 50 mg/kg (the second group of AG), 100 mg/kg (the third group of AG) in 5ml NS, respectively. Urine output was recorded at the following time points, before injecting IPS (T(0)), shock (T), 1 h (T(1)), 2 h (T(2)), 3 h (T(3)), 4 h (T(4)), 5 h (T(5)) and 6 h (T(6)) after shock. Plasma nitrate and nitrite (NO(3)(-)/NO(2)(-), stable products of NO), BUN, Scr, RBP were determined at the time points of T, T(2), T(4) and T(6). RESULTS: LPS increased NO(3)(-)/NO(2)(-), BUN, Scr, RBP [from (47 +/- 5) micro mol/L, (5.8 +/- 1.5) mmol/L, (41 +/- 10) micro mol/L, (240 +/- 61) ng/L (T(0)) to (160 +/- 18) micro mol/L, (15.5 +/- 1.8) mmol/L, (166 +/- 23) micro mol/L, (1580 +/- 180) ng/L (T(6)), respectively, P < 0.01]; Urine output decreased significantly [from (17.6 +/- 2.8) ml (T(0)) to (1.3 +/- 0.6) ml (T(6)), P < 0.01]. AG attenuates the increasing of NO(3)(-)/NO(2)(-), BUN, Scr and RBP, and decreasing of urine output. NO(3)(-)/NO(2)(-) of the first, second and third group of AG at T(6) were (58 +/- 8), (50 +/- 14) and (46 +/- 9) micro mol/L, respectively. Compared to LPS group, there was a significant difference (P < 0.01). BUN was (8.2 +/- 2.9), (7.5 +/- 1.9) and (5.5 +/- 1.8) mmol/L, respectively at T(6). Compared to LPS group, there was a significant deference (P < 0.01). RBP was (350 +/- 60), (272 +/- 72) and (248 +/- 103) ng/L, respectively at T(6) (compared to LPS group, there was a significant deference. P < 0.05, < 0.05, < 0.01). Urine output was (11. 1 +/- 2.4), (12. 1 +/- 1. 3) and (17.1 +/- 2. 4) ml, respectively on T(6) (compared to LPS group, there was a significant deference, P < 0.01). AG of 100 mg/kg showed the best effect among three AG groups. CONCLUSION: AG inhibited NO formation in dose-depended and time depended way. AG attenuated the changes of renal function induced by NO.

Animals↗
PubMed2004

Ionic mechanisms of a novel neurotoxin from the sea anemone Anthopleura sp. in rat ventricular myocytes.

OBJECTIVE: To determine the ionic mechanisms of a novel neurotoxin rhk2a obtained from the sea anemone Anthopleura sp. in rat ventricular myocytes. METHODS: Whole-cell patch-clamp recording technique was used to record the sodium, calcium, and sodium-calcium exchange currents (I(Na), I(Ca, L), and I(Na-Ca), respectively) in the isolated single rat ventricular myocytes with or without rhk2a treatment. RESULTS: The current-voltage (I-V) relationship for whole-cell I(Na) in the non-treated and rhk2a-treated (at the dose of 1 micromol/L) myocytes showed no significant difference (P>0.05), but the time constants for inactivation (tau(h)) were significantly greater (P<0.05) for the treated cells over the entire course of the experiment, while the time constants for activation (tau(m)) exhibited no significant difference between the two cells. The inactivation curve of I(Na) of rhk2a-treated cells was similar to that of the non-treated cells, as with the I-V relationship for whole-cell L-type calcium current (I(Ca, L) and I(Na-Ca)). CONCLUSIONS: Delayed inactivation of Na(+) channel plays an important role in the positive inotropic effect of rhk2a, possibly resulting from the alteration in Na(+) channel kinetics induced by rhk2a. rhk2a does not directly affect I(Ca, L), or I(Na-Ca).

Animals↗
PubMed2004

[Systematic assessment on randomized controlled trials for treatment of stable angina pectoris by compound salvia pellet].

OBJECTIVE: To assess the therapeutic effect and safety of compound salvia pellet (CSP) in treating stable angina pectoris (SAP). METHODS: Literatures regarding randomized clinical trials of CSP versus nitrate ester preparation in treating SAP, without any language limitation, were reviewed. Jadad scale was used to assess the methodological quality of the inclusive trials, and Cochrane systematic evaluation was applied for it. RESULTS: Seventeen randomized trials conformed to the inclusion criteria were reviewed, all in Chinese language. The combined results of the two comparing groups on therapeutic effect in symptom of angina and electrocardiogram (ECG) showed that the relative risk (RR) was 1.12 (1.06, 1.19) and the 95% credibility interval (CI) was 1.42 (1.20, 1.57). CONCLUSION: Based on the Cochrane systematic review, CSP showed the therapeutic effect in treating SAP on relieving angina and improving ECG better than that of nitrate ester preparation, and with less adverse reaction and good tolerance. However the conclusion cannot be reached yet due to the low methodological quality of the trials collecting and lacking in some important final markers and relevant criteria for quality of life, more rationally designed and strictly executed randomized trials with large samples are necessary.

Angina Pectoris↗
PubMed2004

Diagnosis and treatment of malignant pancreatic endocrine tumour.

OBJECTIVE: To summarize our experience in the diagnosis and treatment of malignant pancreatic endocrine tumour. METHODS: We retrospectively reviewed 36 cases of malignant pancreatic endocrine tumours in our hospital from July 1987 to April 2002, and summarized its clinical features. RESULTS: Liver metastasis was the main malignant manifestation of malignant pancreatic endocrine tumours (incidence rate 72.2%). Removals of primary lesion and isolated hepatic metastatic lesion were means of curative therapy. Interventional chemotherapy was an important adjuvant treatment. CONCLUSION: Comprehensive therapy plays an important role in improving the prognosis of malignant pancreatic endocrine tumour.

Adult↗
PubMed2004

Brain hyaluronan binding protein inhibits tumor growth.

BACKGROUND: Great efforts have been made to search for the angiogenic inhibitors in avascular tissues. Several proteins isolated from cartilage have been proved to have anti-angiogenic or anti-tumour effects. Because cartilage contains a great amount of hyaluronic acid (HA) oligosaccharides and abundant HA binding proteins (HABP), therefore, we speculated that HABP might be one of the factors regulating vascularization in cartilage or anti-angiogenesis in tumours. The purpose of this research was to evaluate the effects of hyaluronan binding protein on inhibiting tumour growth both in vivo and vitro. METHODS: A unique protein termed human brain hyaluronan (HA) binding protein (b-HABP) was cloned from human brain cDNA library. MDA-435 human breast cancer cell line was chosen as a transfectant. The in vitro underlying mechanisms were investigated by determining the possibilities of MDA-435/b-HABP colony formation on soft agar, the effects of the transfectant on the proliferation of endothelial cells and the expression levels of caspase 3 and FasL from MDA-435/b-HABP. The in vivo study included tumour growth on the chorioallantoic membrane (CAM) of chicken embryos and nude mice. RESULTS: Colony formation assay revealed that the colonies formed by MDA-435/b-HABP were greatly reduced compared to mock transfectants. The conditioned media from MDA-435/b-HABP inhibited the growth of endothelial cells in culture. Caspase 3 and FasL expressions were induced by MDA-435/b-HABP. The size of tumours of MDA-435/b-HABP in both CAM and nude mice was much smaller than that of MDA-435 alone. CONCLUSIONS: Human brain hyaluronan binding protein (b-HABP) may represent a new kind of naturally existing anti-tumour substance. This brain-derived glycoprotein may block tumour growth by inducing apoptosis of cancer cells or by decreasing angiogenesis in tumour tissue via inhibiting proliferation of endothelial cells.

Animals↗
PubMed2004

[Influence of additives on decomposition of PCDD/Fs during MSWI fly ash melting process].

The melting process of municipal solid waste incinerator (MSWI) fly ash was investigated in order to study the influence of additives on decomposition characteristics of dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans, PCDD/Fs). The melting treatment of MWSI fly ash was performed at a batch-melting furnace with two types of additives, CaO and liquid ceramic (LC), at different melting temperatures, melting atmospheres and treatment times. The results demonstrate that the effect of CaO on PCDD/Fs' decomposition changed with the type of atmosphere. The decomposition and removal efficiency (DRE) of dioxins increased slightly with 20% CaO in an oxidative atmosphere, while it decreased obviously in an inert atmosphere. There is an important influence by liquid ceramic on the decomposition of PCDD/Fs. The DRE of PCDD/Fs in MSWI fly ash increased from 99.997% to 100% with the addition of LC increasing from zero to 10% at 1400 degrees C. The temperature, in which the PCDD/Fs were completely decomposed, decreased from 1460 degrees C to 1100 degrees C when 10% LC was added into fly ash.

Benzofurans↗
PubMed2004

[Construction and screening of the human phage antibody library from a patient with melanoma].

AIM: To construct and screen the human phage antibody library from a patient with melanoma. METHODS: Total RNA was extracted from the peripheral blood mononuclear cells (PBMCs) of a patient with melanoma who has survived for twenty years. The heavy chain Fd fragments and kappa light chains were amplified by RT-PCR. The amplified products were cloned into phagemid vector to construct Fab antibody library. The library was panned with two kinds of melanoma cells for 4 rounds. RESULTS: Antibody library contained 1.2 x 10(8) different clones. Specific phage antibodies against one of the two melanoma cells were obtained after 4 rounds of panning. CONCLUSION: Specific human phage antibodies against melanoma cells were obtained.

Antibodies, Neoplasm↗
PubMed2004

Octreotide inhibits proliferation and induces apoptosis of hepatocellular carcinoma cells.

AIM: To study the effect of octreotide on cell proliferation and apoptosis in different hepatocellular carcinoma (HCC) cells and hepatocytes. METHODS: The proliferation of HCC cells (HepG2, SMMC-7721) and hepatocytes (L-02) was determined by MTT assay. Apoptosis was detected either by fluorescent staining, transmission electron microscopy or flow cytometry. The content of AFP in the supernatant of cultured HCC cells was determined by electrochemiluminescence immunoassay. The expression of SSTR subtypes was identified by RT-PCR. RESULTS: The proliferation of HCC cells and L-02 cells was inhibited significantly by octreotide (0.25, 0.5, 1.0, 2.0 and 4.0 mg/L). However, the apoptosis of HCC cells markedly increased in a concentration-dependent manner. Both the apoptosis index and the percentage of apoptotic cells in L-02 cells were significantly lower than those of HepG2 and SMMC-7721 cells. The content of AFP in the supernatant of cultured HepG2 cells treated with octreotide was also statistically reduced. Furthermore, SSTR2 and SSTR4 were positive in both the hepatocellular carcinoma cells and in the L-02 cells. SSTR3 was only expressed in the two heptatocellular carcinoma cells, and SSTR5 was found in the SMMC-7721 cells. No SSTR1 was detected either in HCC cells or L-02 cells. CONCLUSIONS: Apoptosis induction is a major mechanism of octreotide inhibition on hepatocellular cells. SSTR3 is expressed in the HCC cells, but not in the L-02 cells, which suggests a molecular basis for the HCC-selective effects of octreotide.

Antineoplastic Agents, Hormonal↗
PubMed2004

[Positional analysis of a gene related to salt tolerance in Sinorhizobium meliloti by transposon rescue].

Salt sensitive mutant 042BML-2 was obtained by mutating Sinorhizobium meliloti 042BM with transposon Tn5 carried on the plasmid pRL1063a. By transposon rescue, a 1.179 kb of DNA sequence of S. meliloti flanking the Tn5 insertion site was obtained. The sequence similarity analysis through BLAST analysis in GenBank revealed the transposon was inserted into a functionally unknown gene, which is 6 270 bp in length, of S. meliloti, and the gene was named rtsC. This study indicated that rtsC was associated with salt tolerance in S. meliloti 042BM. Hydrophobicity profile analysis of the putative amino acid sequence showed that two predicted transmembrane domains existed in N-terminal portion of RtsC. The significance of RtsC protein in the salt-tolerance in S. meliloti was discussed.

Amino Acid Sequence↗
PubMed2004

[Occurrence and predictive factors of hepatitis B virus polymerase YMDD variation among patients with chronic hepatitis B and liver cirrhosis during lamivudine therapy].

OBJECTIVE: To study the incidence and the predictive factors of HBV polymerase YMDD variation among patients with chronic hepatitis B and liver cirrhosis during lamivudine therapy. METHODS: The clinical data and serial sera of 313 chronic HBV infected patients (249 chronic hepatitis B and 64 liver cirrhosis) treated with lamivudine were collected. YMDD variations were determined by mispairing PCR-RFLP assay. The data were analyzed using SPSS software. RESULTS: The cumulative rates of variation among patients with chronic hepatitis B and liver cirrhosis were 8.84% and 17.19%, 20.91% and 32.40%, 26.92% and 39.56%, 26.92% and 58.79% after 12, 24, 36 and 48 months of lamivudine treatment, respectively. The results of log-rank test and Cox's proportional hazard model analysis indicated that lamivudine monotherapy, low ALT level, high HBV DNA level, and the patients with liver cirrhosis at baseline were significantly related to an occurrence of YMDD variation. CONCLUSION: This study suggests that lower ALT and higher HBV DNA levels at baseline before lamivudine treatment, lamivudine monotherapy without combining alpha-interferon, and the patients with liver cirrhosis seem to be statistically significant for predicting the occurrence of YMDD variation.

Adolescent↗