Biomedical subjects

Lan Zhang

Publications and source records attributed to Lan Zhang.

At least 37 records · Page 2Linked to original sources

PubMed2006

[Assessment of taste development in 62 newborn infants].

OBJECTIVE: To study the differential facial responses to four basic tastes of the newborns and the gender-related different taste sensitivity. METHODS: Sixty-two newborns (31 females and 31 males) born in the Department of Obstetrics, First Hospital of the Chongqing University of Medical Sciences were tested for responses to four solutions, including 25% sucrose (sweet), 5% sodium chloride (salt), 1.43% citric acid (sour), and 0.025% berberine (bitter) 90 minutes after birth. The inclusion criteria were: (1) medically uncomplicated full-term pregnancy; (2) medically uncomplicated spontaneous vaginal delivery; (3) Apgar score of at least 8 at 1 and 5 min. All the infants were found to be normal and healthy on pediatric examination. The facial responses of the newborns were recorded by video. The facial responses were divided into nine facial action units and expressions from A1 to C3, which are also expressed as the 1 - 9 grades of intensity, crying was included as grade 9 and nausea was defined as grade 10 intensity. The distinctions of the facial responses were analyzed by chi-square test. The distinctions of sex in the facial responses were analyzed by the Wilcoxon test. RESULTS: All the newborns were full term, excluding the medical conditions. The average birth weight of the newborns was 3324.3 g. The data from the study indicated that absence of distinctive mouth action or sucking was the major facial response of the infants to sucrose solution (P < 0.01). There were no special expressions when the newborns were given the salt solution (P > 0.01). The lip pursing with negative brow and middle face actions were major response of the infants to the sour solution (citric acid) (P < 0.01). The expressions in response to the bitter solution of the infants were the mouth gaping with negative brow and middle face actions (P < 0.01). The facial responses to the sweet and bitter solutions in the boys were more sensitive than those in the girls (P < 0.01). There was no sex difference in the intensities of the facial responses to the salt and sour solutions (P > 0.05). CONCLUSIONS: The newborns had distinct responses to the four solutions shortly after birth. The facial expression to sweet and bitter solutions in the boys were more sensitive than in the girls.

Berberine↗

PubMed2006

[Bcl-XL antisense oligodeoxynucleotide sensitizes human esophageal cancer cell line to 5-fluorouracil].

OBJECTIVE: To investigate the effects of the Bcl-XL antisense oligodeoxynucleotides (ASODN) in suppressing the Bcl-XL expression and increasing the sensitivity of esophageal cancer cell line EC9706 to 5-fluorouracil (5-Fu). METHODS: The proliferation inhibitory rate of EC9706 was assessed by MTT, the expression of Bcl-XL was detected by RT-PCR and Western blot, and the apoptotic changes were examined by acridine orange (AO) fluorescent staining and flow cytometry, respectively. RESULTS: In the group of ASODN combined with 5-Fu, the proliferation inhibitory rate of esophageal cancer cells was 71.58%, the expression inhibitory rate of Bcl-XL mRNA was 81.25%, the expression of Bcl-XL protein was decreased significantly. The apoptosis rates detected by AO fluorescent staining and flow cytometry were 69.5% and (63.32 +/- 9.23)%, respectively. There were significant differences as compared with the cell control group, the vacuity control group, the N-ODN group, the ASODN group and the 5-Fu group, respectively (P < 0.05). CONCLUSION: Bcl-XL ASODN combined with 5-Fu can effectively inhibit the proliferation of esophageal cancer cells in vitro. Bcl-XL ASODN can significantly increase the sensitivity of esophageal cancer cells to 5-Fu through suppressing the expression of Bcl-XL.

Antimetabolites, Antineoplastic↗

PubMed2006

[Modern biological basis of Chinese medical theory that "kidney nourishes marrow and brain is sea of marrow"].

The theory that "the kidney nourishes marrow and brain is the sea of marrow" has been instructing traditional Chinese medical doctors in preventing and treating dementia in aged people for thousands of years. However, the modern biological basis of this theory has not been systemically studied. In this review, we summarized our serial pharmacological studies on the treatment of Alzheimer's disease (AD) with Chinese medicinal herbs, using multiple kinds of AD-like animal and cell models. The results show that "kidney-reinforcing" herbs of traditional Chinese medicine play a very important role in the anti-AD effects; and different "kidney-reinforcing" herbs have different effects in brain functions. The common effects of "kidney-reinforcing" herbs are improving cellular energy metabolism, increasing neurotrophic factors and the number of cholinergic neurons, and decreasing neurotoxin production. Based on above results, we propose that the essence of "brain marrow" is the neurons and neurotrophic factors in the brain; "the deficiency of brain marrow" is induced by the decrease in neurotrophic factors and the atrophy and loss of neurons in the brain, thus resulting in cognitive impairment and dementia. The modern biological basis of "reinforcing kidney to replenish marrow" by traditional Chinese medicine includes improving cellular energy metabolism and utilization, enhancing endogenous neurotrophic effects and decreasing neurotoxin production, thus reducing the cell death and increasing the survival and regeneration of neurons.

Alzheimer Disease↗

PubMed2005

Two independent pathways traffic the intraperoxisomal peroxin PpPex8p into peroxisomes: mechanism and evolutionary implications.

Among peroxins involved in peroxisome biogenesis, only Pex8p is predominantly intraperoxisomal at steady state. Pex8p is necessary for peroxisomal matrix protein import via the PTS1 and PTS2 pathways. It is proposed to bridge two peroxisomal membrane subcomplexes comprised of the docking (Pex13p, Pex14p, Pex17p) and RING (Pex2p, Pex10p, Pex12p) peroxins and is also implicated in cargo release of PTS1 proteins in the matrix. We show that Pichia pastoris Pex8p (PpPex8p) enters the peroxisome matrix using two redundant pathways in a Pex14p-dependent, but Pex2p-independent, manner, showing that the intact importomer and RING subcomplex are not required for its import. One pathway depends on the TPR motifs in Pex5p, the C-terminal PTS1 sequence (AKL) in PpPex8p, and the intraperoxisomal presence of this peroxin. The alternative pathway uses the PTS2 receptor, Pex7p, its accessory protein, Pex20p, and a putative PTS2 motif in PpPex8p, but does not require intraperoxisomal PpPex8p. Pex20p interaction with PpPex8p is independent of Pex7p, but the interaction of PpPex8p with Pex7p requires Pex20p. These data suggest a direct interaction between PpPex8p and Pex20p. Our studies shed light on the mechanism and evolution of the dual import pathways for PpPex8p.

Amino Acid Motifs↗

PubMed2005

Gigaxonin interacts with tubulin folding cofactor B and controls its degradation through the ubiquitin-proteasome pathway.

Gigaxonin is mutated in human giant axonal neuropathy (GAN), an autosomal recessive neurodegenerative disorder. The presence of generalized cytoskeletal abnormalities , including few microtubules and accumulated intermediate filaments (IFs), in GAN suggests an essential role of gigaxonin in cytoskeletal organization and dynamics. However, the molecular mechanisms underlying the cytoskeletal pathology remain to be elucidated. Over the years, the ubiquitin-proteasome system (UPS) of intracellular protein degradation has been implicated in the control of many fundamental cellular processes. Defects in this system seem to be directly linked to the development of human diseases, including cancers and neurodegenerative diseases . Here, we show that gigaxonin controls protein degradation of tubulin folding cofactor B (TBCB) , a function disrupted by GAN-associated mutations. The substantial TBCB protein accumulation caused by impaired UPS may be a causative factor of cytoskeletal pathology in GAN. Our study provides important insight into pathogenesis of neurodegenerative diseases associated with cytoskeletal abnormalities.

Animals↗

PubMed2005

Determination of the hydrolysis rate constants and activation energy of aesculin with capillary electrophoresis end-column amperometric detection.

Aesculetin is the product of the hydrolysis reaction of aesculin. A high sensitivity and good repeatability method based on capillary electrophoresis with amperometric detection (CE-AD) was developed for simultaneous determination of aesculin and aesculetin in the hydrolysate of aesculin. Under the optimum condition: 10mmol/L KH(2)PO(4)-5mmol/L Na(2)B(4)O(7) (pH 6.0) buffer, separation at 18kV and +900mV (versus Ag/AgCl) as the detection potential, the hydrolysis rate constants of aesculin hydrolysis at 25, 30, 35, 40 and 45 degrees C in 0.1mol/L KOH were obtained as 1.45x10(-2)min(-1), 2.01x10(-2)min(-1), 2.93x10(-2)min(-1), 3.76x10(-2)min(-1) and 5.05x10(-2)min(-1), respectively. It was calculated that the activation energy for aesculin hydrolysis was 49.4kJ/mol.

Buffers↗

PubMed2005

Synthesis of 2,3-diaryltetrazole-5-thiones and theoretical studies on atomic charge distributions of 2,3-diphenyltetrazole-5-thione.

Four 2,3-diaryltetrazole-5-thiones have been synthesized in high yields using a new synthetic method under mild reaction conditions. Theoretical calculations of the structure, vibrational frequencies, and natural population analysis (NPA) of atomic charge distributions on 2,3-diphenyltetrazole-5-thione 1 have been performed by DFT-B3LYP, HF, and MP2 methods using several basis sets. According to the NPA results a new resonance hybrid structure of 1 has been proposed with an exocyclic sulfur atom and a tetrazole ring carrying negative charges and two phenyl rings having positive charges. On the basis of this new proposed structure, the calculated results can explain experimental facts logically. In addition, a new chemical property of 1 has been predicted: the protonation should occur not only on the exocyclic S atom, but also on the N atoms having negative charges.

Journal Article↗

PubMed2005

Expression of heparanase mRNA in anti-sense oligonucleotide-transfected human esophageal cancer EC9706 cells.

AIM: To investigate the effects of anti-sense oligonucleotides (ASODNs) on mRNA expression of heparanase in human esophageal cancer EC9706 cells. METHODS: One non-sense oligonucleotide (N-ODN) and five ASODNs against different heparanase mRNA sites were transfected into EC9706 cells, then the expression of heparanase mRNA in EC9706 cells was studied by in situ hybridization. RESULTS: The expression of heparanase mRNA could be inhibited by ASODNs. There was no significant difference among five ASODNs (P>0.05), but there was a significant difference between ASODNs and N-ODN or non-transfected group (ASODN1: 2.25+/-0.25, ASODN2: 2.21+/-0.23, ASODN3: 2.23+/-0.23, ASODN4: 2.25+/-0.24 vs N-ODN: 3.47+/-2.80 or non- transfected group: 3.51+/-2.93 respectively, P<0.05). CONCLUSION: The expression of heparanase mRNA in EC9706 cells can be inhibited by ASODNs in vivo, and heparanase ASODNs can inhibit metastasis of esophageal squamous cell carcinoma or other tumors by inhibiting the expression of heparanase.

Cell Line, Tumor↗

PubMed2005

L-arginine administration ameliorates serum and pulmonary cytokine response after gut ischemia-reperfusion in immature rats.

AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats. METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor alpha (TNFalpha) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage. RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17+/-42.93 micromol/L) when compared with IR group (87.57+/-23.17 micromol/L, t = 3.190, P = 0.008<0.01). Serum MDA reduced significantly in IR+L-arg group (8.93+/-1.50 nmol/L) when compared with SHAM (23.78+/-7.81 nmol/L, t = 3.243, P = 0.007<0.01) and IR (25.54+/-9.32 nmol/L, t = 3.421, P = 0.006<0.01). ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81+/-7.84 pg/mL) than that in SHAM (35.52+/-10.82 pg/mL, t = 2.571, P = 0.03<0.05) and IR (50.83+/-22.05 pg/mL, t = 3.025, P = 0.009<0.01) groups. MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73+/-1.99 nmol/L) than in SHAM (16.62+/-2.28 nmol/L, t = 3.280, P = 0.007<0.01) and IR (21.90+/-4.82 nmol/L, t = 3.322, P = 0.007<0.01) groups. Serum and lung TNFalpha concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50+/-8.92, 33.20+/-16.59, and 22.50+/-6.09 in SHAM, IR, and IR+L-arg groups, respectively. CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats. Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group. L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).

Age Factors↗

PubMed2005

Separation and determination of L-tryptophan and its metabolites by capillary micellar electrokinetic chromatography with amperometric detection.

A high-performance method of capillary micellar electrokinetic chromatography (CMEKC) with amperometric detection (AD), using a newly designed pre-aligned electrochemical cell, has been developed for the separation and determination of L-tryptophan (Trp) and its eight metabolites including 3-hydroxy-L-kynurenine (3-HK), 5-hydroxy-L-tryptophan (5-HTP), L-kynurenine (KN), 5-hydroxyindole-3-acetic acid (5-HIAA), xanthurenic acid (XA), indole-3-pyruvic acid (IPA), 5-hydroxytryptamine (5-HT), and tryptamine (Tryp). A carbon disk electrode was used as the working electrode and the optimal detection potential was 0.85 V (versus Ag/AgCl). At 24 kV of applied voltage, the nine compounds were completely separated, within 23 min, in a 10 mol/L Na(2)HPO(4)-NaOH buffer (pH 11.0) containing 40 mmol/L sodium dodecyl sulfate (SDS) and 3% methanol (v/v). A good linear relationship was obtained for all analytes in this paper and the detection limits of 3-HK, 5-HTP, KN, Trp, 5-HIAA, XA, IPA, 5-HT, and Tryp were 7.42, 5.18, 34.6, 3.99, 15.1, 12.7, 260, 6.72, and 8.01 nmol/L, respectively. This method has been applied to analyze the metabolism of Trp in rabbit urine.

Animals↗

PubMed2005

Features of reovirus outer capsid protein mu1 revealed by electron cryomicroscopy and image reconstruction of the virion at 7.0 Angstrom resolution.

Reovirus is a useful model for addressing the molecular basis of membrane penetration by one of the larger nonenveloped animal viruses. We now report the structure of the reovirus virion at approximately 7.0 A resolution as obtained by electron cryomicroscopy and three-dimensional image reconstruction. Several features of the myristoylated outer capsid protein mu1, not seen in a previous X-ray crystal structure of the mu1-sigma3 heterohexamer, are evident in the virion. These features appear to be important for stabilizing the outer capsid, regulating the conformational changes in mu1 that accompany perforation of target membranes, and contributing directly to membrane penetration during cell entry.

Algorithms↗

PubMed2005

Degradation of Alyssum murale biomass in soil.

The Ni-hyperaccumulating plant Alyssum murale accumulates exceptionally high concentrations of nickel in its aboveground biomass. The reasons for hyperaccumulation remain unproven; however, it has been proposed that elemental alelopathy might be important. High-Ni leaves shed by the plant may create a "toxic zone" around the plant where germination or growth of competing plants is inhibited. The efficacy of this argument will partially depend upon the rate at which leaves degrade in soil and free metals are released, and the subsequent rate at which metals are bound to soil constituents. To test the degradation of biomass of hyperaccumulators, A. murale was grown on both high- and low-Ni soils to achieve high- (12.0 g Ni/kg) and low- (0.445 g Ni/kg) Ni biomass. Shredded leaf and stem biomass were added to a serpentine soil from Oregon that was originally used to grow high-Ni biomass and a low-Ni control soil from Maryland. Biomass Ni was readily soluble and extractable, suggesting near immediate release as biomass was added to soil Extractable nickel in soil amended with biomass declined rapidly over time due to Ni binding in soil These results suggest that Ni released from biomass of Ni hyperaccumulators may significantly affect their immediate niche only for short periods of time soon after leaf fall, but repeated application may create high Ni levels under and around hyperaccumulators.

Biodegradation, Environmental↗

PubMed2005

[The relationship between intrathyroidal dendritic cells and humoral immune disorder in Graves' disease].

OBJECTIVE: To investigate the relationship between intrathyroidal dendritic cells and humoral immune disorder in Graves' disease. METHODS: With the use of S-100 protein antibodies and the help of SP immunohistochemical method, the number and distribution of S-100 protein positive dendritic cells were observed in thyroid glands from 34 patients with Graves' disease and 5 controls. Serum thyroid stimulating antibodies (TSAb) before operation were measured with human embryo-kidney cells expressing the recombinant thyrotrophin receptor. The correlation between the infiltrating degree of intrathyroidal dendritic cells and the values of serum TSAb was analyzed in patients with Graves' disease. RESULTS: In normal thyroid glands, no S-100 protein positive dendritic cells were found. Dendritic cells were seen in all observed thyroid glands from patients with Graves' disease. Most of the dendritic cells were seen in close contact with the adjacent thyroid epithelial cells or infiltrating lymphocytes. The infiltrating degree of intrathyroidal dendritic cells in Graves' disease correlated closely with the values of serum TSAb (r = 0.4461, P < 0.01). CONCLUSION: It is suggested that the intrathyroidal dendritic cells have a close relation with humoral immune disorder and play an important role in the initiation and/or maintenance of thyroid autoimmune reaction in Graves' disease.

Adult↗

PubMed2005

[Capillary electrophoresis with end-column electrochemical detection for hydrochlorothiazide and triamterene diuretics].

A method based on capillary electrophoresis with end-column electrochemical detection (HPCE-ED) was developed for the determination of the diuretics of hydrochlorothiazide (HCT) and triamterene (TAT) simultaneously. The detection electrode was a 300 microm carbon disc electrode at a working potential of +1.1 V versus Ag/AgCl electrode. The two analytes could be well separated within 8 min in a 50 cm long capillary at a separation voltage of 24 kV with a 10 mmol/L phosphate buffer (pH 7.5). Under optimum conditions, the current response was linear over about two orders of magnitude with detection limits (S/N = 3) of 0.29 and 0.25 mg/L for triamterene and hydrochlorothiazide, respectively. The proposed method was successfully applied to determine the synthetic urine and real pharmaceuticals samples. The recoveries were found to be in the range of 93.5%-97.2%.

Diuretics↗

PubMed2005

[Simultaneous determination of 7-methylguanosine and mitomycin C by capillary electrophoresis with amperometric detection].

A method based on capillary electrophoresis with amperometric detection (CE-AD) has been developed for the simultaneous determination of 7-methylguanosine and mitomycin C. The detection electrode was a 0.3 mm carbon disc electrode at a working potential of 950 mV (versus Ag/AgCl electrode). A suitable electrolyte consists of 20 mmol/L phosphate buffer (pH 9.4), with the separation voltage of 18 kV, the injection time of 10 s, and the injection voltage of 18 kV. Under optimum conditions, the two analytes could be well separated within 10 min in a 60 cm length capillary. The current responses were linear over about two orders of magnitude (0.50 - 50 mg/L) with detection limits (S/N = 3) of 0. 050 and 0.025 mg/L for 7-methylguanosine and mitomycin C, respectively. The proposed method was successfully applied to determine the synthetic urine and serum samples. The recoveries were found in the range of 93.0% - 97.2%.

Alkylating Agents↗

PubMed2005

[Inhibitory effects of transfected Bcl-XL antisense oligodeoxynucleotide on proliferation of esophageal cancer cells and growth of human esophageal carcinoma in nude mice].

OBJECTIVE: To investigate the biologic effects of Bcl-XL antisense oligodeoxynucleotide (ASODN) transfected into cultured esophageal carcinoma cells and human esophageal carcinoma xenograft in nude mice. METHODS: Cationic liposome-mediated ASODN was used to transfect esophageal carcinoma cells. RT-PCR, Western blot, MTT assay, flow cytometry and in-situ apoptosis cells detection (TUNEL detection) were used to systematically study the biological effects of the transfected cells in vitro and in vivo. RESULTS: MTT assay showed that the proliferation of esophageal carcinoma cells in the ASODN group decreased significantly as compared with control (P < 0.05), along with a 57.3% inhibitory rate of Bcl-XL mRNA, a significant decrease of Bcl-XL protein and the apoptosis rates of (31.1 +/- 5.8)% and 35.0% by flow cytometry and TUNEL assay, respectively (P < 0.01, as compared with controls). The growth of human esophageal carcinoma in nude mice was also significantly inhibited in the ASODN group (P < 0.05), along with a significant decrease of Bcl-XL mRNA and protein expression, and also an enhanced apoptosis of the tumor cells in nude mice. CONCLUSIONS: Bcl-XL ASODN can effectively inhibit the proliferation of esophageal carcinoma cells in vitro and the growth of the tumor in vivo. The suppression of Bcl-XL expression by ASODN may offer both a therapeutic approach and an important theoretic foundation for gene therapy against esophageal carcinoma.

Animals↗

PubMed2004

[Endothelial nitric oxide synthase gene transfected endothelial cells inhibit smooth muscle cell proliferation and platelet aggregation early in vitro].

OBJECTIVE: To test the function of endothelial cells transfected eNOS gene. METHODS: To test the function of eNOS-overexpressing endothelial cells inhibiting smooth muscle cell proliferation and platelet aggregation in vitro by colorimetry, MTT and (3)H-TdR permeate, respectively, in four different endothelial cells groups. RESULTS: The platelet aggregation is significantly decreasing between the groups of EC and eNOS at the different time (P < 0.05), is 42.2 and 32.6 separately at the time of 120 h. The SMC proliferation is significantly decreasing between the groups of EC and eNOS at the different time (P < 0.05). It is 0.28 and 0.22 by MTT test, 4691 and 3995 by (3)H-TdR permeate separately at the time of 120 h. CONCLUSIONS: eNOS-overexpressing endothelial cells inhibited significantly smooth muscle cells proliferation and platelet aggregation in vitro; which shows powerful effect 48 hours post transfection and lasts up to 120 hours at the least; and were held back by L-NAME.

Animals↗

PubMed2004

Simultaneous determination of allantoin, choline and L-arginine in Rhizoma Dioscoreae by capillary electrophoresis.

A rapid, easy and reproducible capillary electrophoresis (CE) method for the simultaneous determination of allantoin, choline and arginine in Rhizoma Dioscoreae was developed first time. Under the optimum condition, the three analytes could be well separated within 5 min in a 70 cm (60 cm effective length) x 75 microm i.d. capillary. The relative standard deviations for both migration time and peak height were less than 3.20%. The linear response range was 5.0-150, 0.9-100 and 1.0-200 microg/ml for arginine, choline and allantoin, respectively. The detection limit of three components was 2.0, 0.4 and 0.5 microg/ml for arginine, choline and allantoin, respectively. Contents of arginine, choline and allantoin in the crude drug of Rhizoma Dioscoreae could be easily determined by the proposed method with satisfactory results.

Allantoin↗