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Biomedical subjects

Q Huang

Publications and source records attributed to Q Huang.

At least 145 records · Page 8Linked to original sources
PubMed1999

Purification of human chorionic gonadotrophin from urine by membrane filtration affinity chromatography with a positively charged membrane.

UNLABELLED: A new method of affinity chromatography, termed membrane filtration affinity chromatography (MFAC), has been developed and applied to purify HCG from urine. By filtrating urine through ZBM (HCG in urine would bind to the antibody on ZBM) and by dissociating the HCG from the antibody on ZBM in purified form, we developed the MFAC and purified HCG from urine of pregnant women by MFAC. The purified HCG showed a single band in polyacrylamide gel electrophoresis. ZBM (1 cm(2)) could harvest 90.3 microg HCG, which showed immunoactivity of 8554 IU/mg. The rate of recovery was 87%. CONCLUSION: MFAC with ZBM is an effective method, which is much easier and cheaper than conventional affinity chromatography for purification of proteins from solution, especially from highly diluted solution.

Chorionic Gonadotropin↗
PubMed1999

T grafts with the right internal thoracic artery to left internal thoracic artery versus the left internal thoracic artery and radial artery: flow dynamics in the internal thoracic artery main stem.

OBJECTIVE: Complete arterial coronary artery bypass grafting with 2 grafts can be achieved even in triple vessel disease by use of a T configuration. There is still uncertainty whether the coronary flow reserve in the main stem of the left internal thoracic artery is sufficient to supply more than 1 anastomosed coronary vessel. METHODS: Between March 1996 and February 1999, 251 patients with multivessel coronary artery disease underwent complete arterial revascularization with T grafts, using either the left internal thoracic artery with the free right internal thoracic artery graft (n = 73, group I) or the left internal thoracic artery and radial artery (n = 178, group II). A mean of 4.0 (group I) versus 4.3 (group II) coronary vessels were anastomosed per patient. One week (n = 92) and 6 months (n = 28) after the operation, flow was measured in the proximal left internal thoracic artery with a Doppler guide wire. Maximum flow was determined after injection of adenosine (30 microg). RESULTS: The in-hospital mortality was 2.7% (group I) versus 2.3% (group II). At angiography (n = 142, 56.6%) the patency rate was 96.3% (group I) versus 98.2% (group II). There was no significant difference between baseline flow, maximum flow, and coronary flow reserve between the 2 groups. Coronary flow reserve increased in both groups within the first 6 postoperative months (group I, 1.85 +/- 0.31 vs 2.77 +/- 0.77, P =.0002; group II, 1.82 +/- 0.4 vs 2.53 +/- 0.73, P =.009). CONCLUSION: Both variants of T grafts allow for complete arterial revascularization with good perioperative results. The flow reserve of the proximal internal thoracic artery is adequate for multiple coronary anastomoses irrespective of the choice of the second arterial graft.

Blood Flow Velocity↗
PubMed1999

Reducing degradation of azo dye by zero-valent iron in aqueous solution

The reducing degradation kinetics of five azo dyes, Acid orange II, Acid orange IV, Acid orange GG, Acid red 3B and Orange I, by zero-valent iron powder in aqueous solution were studied. It showed that the degradation is a two-step reaction, with the first step being reversible. Solution acidity and iron surface area are the factors greatly influencing the degradation rates, and with increasing of acidity and iron surface area, the degradation rates increase.

Journal Article↗
PubMed1999

Free flow capacity of skeletonized versus pedicled internal thoracic artery grafts in coronary artery bypass grafts.

OBJECTIVE: The internal thoracic artery (ITA) is the ideal conduit for coronary artery bypass grafting (CABG). The skeletonization technique of this arterial conduit has been proposed to reduce chest wall trauma, increase graft length and facilitate construction of sequential anastomoses. Nevertheless, some surgeons decline this technique because of potentially increased trauma to the ITA with impairment of flow. In this investigation we compared the free flow of skeletonized with that of pedicled ITA grafts. METHODS: Two surgeons operated on 80 consecutive patients with coronary artery disease for elective CABG. In group I (n = 40), the left ITA was dissected using the skeletonization technique. In group II (n = 40), it was harvested as a pedicled graft. In 23 patients of group I both ITA's were dissected in skeletonized fashion for complete arterial revascularization. Diluted papaverine was instilled into the lumen of the ITA after distal transection of the vessel in both groups. Free flow of the ITA was registered before and 15 min after intraluminal application of diluted papaverine. Mean arterial pressure was maintained at 70 mmHg. RESULTS: Before the application of papaverine, free flow of skeletonized and pedicled ITA grafts was identical between the two groups. After treatment with papaverine maximum free flow was significantly higher in the skeletonized ITA's (group I 197.2 (+/-66.6) ml/min; group II 147.1 (+/-70.5) ml/min; P < 0.05). There was no significant difference between free flow after dilatation of the left and right ITA in group I (left 197.2 (+/-66.6) ml/min; right 198.9 (+/-61.8) ml/min). CONCLUSIONS: Preparation of the ITA with the skeletonization technique results in significantly, higher free flow capacity than in pedicled grafts. This may increase the safety of arterial revascularization by reducing the risk of ITA hypoperfusion syndrome.

Aged↗
PubMed1999

Enhanced antitumor activity of sarCNU in comparison to BCNU in an extraneuronal monoamine transporter positive human glioma xenograft model.

A novel analogue of nitrosoureas, 2-chloroethyl-3-sarcosinamide-1-nitrosourea (SarCNU), has demonstrated increased anticancer effects in vitro and in vivo. Our previous work suggested that SarCNU enters cells via the extraneuronal monoamine transporter (EMT), that contributes to its enhanced cytotoxicity. In the present study, comparative activities of SarCNU and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) were evaluated in an EMT positive human glioma xenograft model. Athymic nude mice implanted subcutaneously or intracranially with human glioma SHG-44, a cell line that has been confirmed EMT positive by using reverse-transcription polymerase chain reaction (RT-PCR) assay, were treated with SarCNU at an optimal dose of 167 mg/kg, or BCNU at 20 mg/kg or 30 mg/kg, q4d x 3 intraperitoneally (i.p.). In 17 animals with subcutaneous tumor grafts treated with SarCNU, 9 animals became tumor free and 8 demonstrated tumor regression. While in the BCNU treated group, there were only 2 out of 10 mice in the 20 mg/kg group and 2 out of 7 in the 30 mg/kg group, which demonstrated some tumor regression. There were 4 drug related deaths in the BCNU (30 mg/kg) group, while there were no drug related deaths in the SarCNU group. In the intracranially implanted mice, the median survival time in the SarCNU group was more than 130 days, while in the BCNU treated group it was only 22 days which was similar to the control group (18 days). This is the first demonstration that SarCNU, in comparison to BCNU, has enhanced anticancer activity in an EMT positive human glioma xenograft model.

Animals↗
PubMed1999

Crystal structure of the complex formed between bovine beta-trypsin and MCTI-A, a trypsin inhibitor of squash family, at 1.8-A resolution.

The stoichiometric complex formed between bovine beta-trypsin and Momordica charantia, Linn. Cucurbitaceae trypsin inhibitor A (MCTI-A) was crystallized and its X-ray crystal structure was refined to a final R value of 0.179 using data of 7.0- to 1.8-A resolution. Combination with results on the complex of MCTI-A with porcine trypsin gives the sequence of MCTI-A definitely, of which 13 residues are conserved compared with other squash family trypsin inhibitors. Its spatial structure and the conformation of its primary binding segment from Cys3I (P3) to Glu7I (P3'), which contains a reactive scissile bond Arg5I C-Ile6I N, were found to be very similar to the other squash family proteinase inhibitors.

Amino Acid Sequence↗
PubMed1999

Brain distribution of UCP2 mRNA: in situ hybridization histochemistry studies.

Uncoupling protein-2 (UCP2) is expressed in large amounts in several tissues. In the mouse brain, in situ hybridization studies have revealed an abundant expression of UCP2 mRNA in the ventral septal region, the hypothalamus, the hindbrain (medulla), the ventricular regions and the cerebellum. In the hypothalamus, a very highly intense hybridization signal is apparent in the suprachiasmatic nucleus, in the medial parvicellular and magnocellular lateral parts of the paraventricular hypothalamic nucleus, and in the arcuate nucleus. In the brainstem, UCP2 is found to be strongly expressed in the dorsal motor nucleus of the vagus nerve. The expression of UCP2 mRNA is also clearly noticeable in the choroid plexuses and in the cerebellum. The expression of UCP2 mRNA in specific regions of the brain as well as its presence in neurons with a known chemical identity suggest that UCP2 mRNA is expressed in neurons. It is as yet premature to conclude about a specific function of UCP2 in the brain. The brain distribution pattern of its transcript suggests that this mitochondrial protein could be part of neuronal circuitries involved in the control of neuroendocrine functions and autonomic responses. Assuming that the UCP2 mRNA encodes a functional uncoupling protein, it can be argued that UCP2 contributes to the metabolic rate and thermoregulation of the neuronal structures to which it is associated. In addition, by elevating oxygen consumption in the brain, UCP2 could in specific regions control the production of reactive oxygen species and thereby influence the process of neural degeneration.

Animals↗
PubMed1999

Identification of novel chromosomal rearrangements in acute myelogenous leukemia involving loci on chromosome 2p23, 15q22 and 17q21.

Chromosomal translocations are frequently linked to multiple hematological malignancies. The study of the resulting abnormal gene products has led to fundamental advances in the understanding of cancer biology. This is the first report of t(2;15)(p23;q22) and t(2;17)(p23;q21) translocations in human malignancy. Patient 1, a 73-year-old male, was diagnosed with myeloblastic (FAB M1 sub-type) AML. Cytogenetic analysis showed a 47,XY,t(2;15)(p23;q22),+13 karyotype. Fluorescent in situ hybridization (FISH) showed that the PML gene was transferred intact to the short arm of chromosome 2 while the ALK gene on chromosome 2p23 was passively transferred to the long arm of chromosome 15. Patient 2 was a 60-year-old male diagnosed with monocytic (FAB M4-type) AML. Cytogenetic analysis showed 46,XY,t(2;17)(p23;q21) karyotype. FISH analysis showed that neither RARalpha nor ALK were disrupted by the translocation. None of the coding region of the three genes studied were translocated in these patients. This raises the possibilities that other neighboring genes could be involved or that noncoding regulatory sequences of the studied genes could be put in contact and deregulate expression of other genes. Alternatively, displacement of ALK, RARalpha and PML to novel positions could lead to loss of their normal regulation

Acute Disease↗
PubMed1999

Crystal structure of mung bean inhibitor lysine active fragment complex with bovine beta-trypsin at 1.8A resolution.

The crystal structure of the complex of mung bean inhibitor lysine active fragment with bovine beta-trypsin has been determined by X-ray crystallographic analysis at a resolution of 1.8 A. Refinement of the model of the complex converged at a final R value of 0.16. From the resulting electron density map, about one-third of the residues of the inhibitor were identified and two residues, at position P4 and P2' respectively, were found to be inconsistent with the sequence reported previously. The peptide chain of the inhibitor at the trypsin active site turns back sharply at Pro23I and forms a 9-residue reactive loop, which interacts with trypsin in a similar manner to the other families of inhibitors, suggesting an important and common role of these regions in exhibiting inhibitory activity.

Amino Acid Sequence↗
PubMed1999

Intestinal cytokine response after gut ischemia: role of gut barrier failure.

OBJECTIVE: To investigate the effect of intestinal ischemia with and without a reperfusion injury on intestinal cytokine production and gut permeability. SUMMARY BACKGROUND DATA: In humans and in animal models, the gut has been implicated as a cytokine-producing organ after ischemia/reperfusion (I/R)-type injuries. Because of the limitations of in vivo models, it has been difficult to demonstrate directly that the gut releases cytokines after an I/R injury or whether there is a relation between the magnitude of the ischemic process and the cytokine response. METHODS: Ileal mucosal membranes from rats subjected to sham or 45 or 75 min of superior mesenteric occlusion (SMAO) or 45 minutes of SMAO and 30 minutes of reperfusion (SMAO 45/30) were mounted in the Ussing chamber system. Levels of tumor necrosis factor-alpha and interleukin-6 were serially measured in the mucosal and serosal reservoirs of the Ussing system, as was mucosal permeability as reflected by the passage of bacteria or phenol red across the ileal membrane. In a second group of experiments, Escherichia coli C25 was added to the mucosal reservoir to determine if the cytokine response would be increased. RESULTS: Mucosal and serosal levels of tumor necrosis factor-alpha were equally increased after SMAO, with the highest levels in the 75-minute SMAO group. The highest levels of interleukin-6 were found in rats subjected to 75 minutes of SMAO or SMAO 45/30; the serosal levels of interleukin-6 were four to sixfold higher than the mucosal levels. The addition of E. coli C25 resulted in a significant increase in the amount of interleukin-6 or tumor necrosis factor-alpha recovered from the mucosal reservoir. Increased ileal membrane permeability was observed only in rats subjected to 75 minutes of SMAO or SMAO 45/30. CONCLUSION: These results directly document that the levels of tumor necrosis factor-alpha and interleukin-6 released from the gut increase after an ischemic or I/R injury, such as SMAO, and that there is a relation between the magnitude of the gut ischemic or I/R insult and the cytokine response.

Animals↗
PubMed1999

Effects of leptin on melanin-concentrating hormone expression in the brain of lean and obese Lep(ob)/Lep(ob) mice.

The effect of leptin on the expression of melanin-concentrating hormone (MCH) was investigated in lean and genetically obese Lepob/Lepob mice. Murine leptin was subcutaneously infused using osmotic minipumps. The treatment period extended to 7 days and the daily dose of leptin delivered was 100 microgram/kg of body weight. In situ hybridization was used to assess the effects of leptin infusion on the expression of MCH mRNA. MCH levels in the brain (hypothalamus/thalamus and the remaining part), spleen and testis were measured by radioimmunoassay coupled to HPLC of selected tissue extracts. Leptin significantly reduced final body weight, weight of brown adipose tissue, daily food intake in obese mice but not in lean animals. In obese mice, leptin led to a rapid reduction in food intake which reached statistical significance after only 24 h and which led to a significant reduction in the body weight after 3 days of treatment. Leptin restored the normal circulating levels of glucose and insulin in obese mice. The present results mainly provide evidence for a stimulating effect of leptin infusion on the MCH neuronal system. The hypothalamic/thalamic levels of MCH mRNA and peptide were higher in mice treated with leptin than in mice infused with phosphate-buffered saline. The stimulation of MCH neurons appeared particularly intense in obese mice, in which the effects of leptin infusion led to the reduction in MCH content of neuron fibers and terminals. Leptin did not affect spleen and testis MCH contents. In the light of the acknowledged orexigenic effects of MCH, the results of this study questioned the direct role of MCH in the action of leptin on energy balance. The increase in MCH expression following leptin could occur as a mechanism to compensate the decrease in energy deposition led to by leptin. It may also indicate that MCH mediates the metabolic actions of leptin indirectly or else that leptin influences actions of MCH other than those related to the regulation of energy balance.

Adipose Tissue, Brown↗
PubMed1999

Studies of molecular pharmacophore/receptor models for GABAA/benzodiazepine receptor subtypes: binding affinities of substituted beta-carbolines at recombinant alpha x beta 3 gamma 2 subtypes and quantitative structure-activity relationship studies via a comparative molecular field analysis.

Binding affinities of a series of 44 beta-carbolines with various substituents at the 3-, 4-, 6- and 7-positions are reported at 5 distinct recombinant GABAA/benzodiazepine receptor (BzR) subtypes [alpha x beta 3 gamma 2 (x = 1-3, 5, 6)]. Many of these ligands displayed better selectivity for the alpha 1 containing GABAA isoform. The most selective BCCT 2 and SPH 195 (17) displayed potent affinity (Ki = 0.72 and 7.2 nM for the alpha 1 beta 3 gamma 2 receptor subtype, respectively) and an overall selectivity of 20 and 23 fold, respectively, for the alpha 1 beta 3 gamma 2 receptor subtype. These are the most selective ligands in vitro for the alpha 1 containing GABAA/Bz receptor isoform reported to date to our knowledge. QSAR studies of these ligands for each receptor subtype have been carried out via a Comparative Molecular Field Analysis (CoMFA) and an included volume analysis. Geometries and charge distributions of these ligands have been optimized using ab initio methods (J. Med. Chem., 1992, 35, 4001-4010). Active conformations of flexible 3-alkoxylated beta-carbolines have been examined via a CoMFA approach. QSAR studies via CoMFA support the previous hypothesis that beta-carbolines with different intrinsic activities may follow an alternative alignment rule when they bind into the pharmacophore/receptor site of the BzR. Examination of binding affinities of beta-carbolines by this modeling strategy has established some of the differences, in particular, topologic differences between the lipophilic pockets in the alpha 1 beta 3 gamma 2, alpha 2 beta 3 gamma 2, alpha 3 beta 3 gamma 2, alpha 5 beta 3 gamma 2 and alpha 6 beta 3 gamma 2 subtypes as well as some of the similarities among the pharmacophore/receptor models of these five distinct GABAA/Bz receptor subtypes.

Binding Sites↗
PubMed1999

Studies of molecular pharmacophore/receptor models for GABAA/BzR subtypes: binding affinities of symmetrically substituted pyrazolo[4,3-c]quinolin-3-ones at recombinant alpha x beta 3 gamma 2 subtypes and quantitative structure-activity relationship studies via a comparative molecular field analysis.

A series of symmetrically substituted pyrazoloquinolinones was synthesized to probe the BzR binding site of different GABAA/Bz receptor subtypes. The affinities of the ligands for different BzR subtypes have been determined by radioligand binding assays on 5 distinct recombinant GABAA receptor isoforms [alpha x beta 3 gamma 2 (x = 1,2,3,5, or 6)]. Most of the ligands synthesized exhibited potent biological activity in vitro. Among them, 3 ligands exhibited enhanced affinity for the alpha 2 beta 3 gamma 2 subtype in comparison to the other subtypes, six ligands demonstrated higher affinity for the alpha 3 beta 3 gamma 2 subtype, while 2 ligands showed some enhanced affinity for the alpha 5 beta 3 gamma 2 subtype. The remainder of the ligands exhibited relatively higher affinities at the alpha 1 containing subtype. To map out the steric and electronic differences between the benzodiazepine binding subtypes, a QSAR analysis by the method of Comparative Molecular Field Analysis (CoMFA) of each receptor subtypes was carried out.

Binding Sites↗
PubMed1999

Relationship between bone mineral density and polymorphism of the estrogen receptor gene in healthy postmenopausal women in China.

OBJECTIVE: To investigate the possible relationship between bone mineral density and polymorphism of the estrogen receptor (ER) gene in Shanghai healthy postmenopausal women. METHODS: 250 unrelated healthy postmenopausal women were selected for bone mineral density (BMD) determination by Dual energy X-ray absorptiometry (DEXA) and polymorphism of estrogen receptor gene analyses by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Pvu II polymorphisms of ER gene was associated with low Troch BMD (P = 0.0153) while there was no significant relationship between Xba I polymorphism of ER gene and BMD at any of skeletal sites included in the present study, and the combination of Pvu II and Xba I polymorphisms of ER gene was significantly associated with both low Lumbar 2-4 (P = 0.0369) and Troch (P = 0.0384) BMD. Multiple stepwise regression analysis also indicated that two combined polymorphisms were correlated significantly with Lumbar 2-4 BMD (P = 0.0254) while this correlation was not revealed at any other skeletal sites. CONCLUSION: There is significant relationship between the polymorphism of ER gene and both Lumbar 2-4 BMD and Troch BMD. It is significant to explore the pathogenesis of osteoporosis and to prevent the development of osteoprosis by use of molecular genetics.

Absorptiometry, Photon↗
PubMed1999

[The study on COPD rat model produced by bacterial infection].

OBJECTIVE: To observe the role of bacterial infection in pathogenesis of COPD. METHODS: The COPD animal model was developed by intranasal repeated injecting Klebsiella pneumoniae(K) or pneumococcal pneumoniae(P) into rat respiratory tract. Histomorphyological changes were observed, PaO2, PaCO2 and right ventricular systolic pressure (RVSP) were analysed. RESULTS: 1 week after injecting K and 4 week after injecting P, the epithelia of bronchioles showed obvious injury. From the 4th week there was severe chronic inflammatory process of bronchioles in 2 experimental groups including thickened wall, narrowed lumen and developed emphysema. In addition, the walls of arterioles accompanying bronchioles were also thickened obviously. Right ventricular systolic pressure raised in 2 experimental groups (P < 0.01). From the 16th week, PaO2 dropped and PaCO2 raised in K group. CONCLUSIONS: Repeated injecting intranasally of the proper amount of klebsiella pneumoniae or pneumococcal pneumoniae into rats' lungs can induce rat small airway inflammation and emphysema. Combining with PaO2, PaCO2 and RVSP analysis, we suggest the model established shows main features of COPD.

Animals↗
PubMed1999

[Mutations of several tumor suppressor genes in primary retinoblastoma].

OBJECTIVE: To study the status of several tumor suppressor genes in primary retinoblastoma. METHODS: Single stranded conformation polymorphism (SSCP) analysis associated with direct DNA sequencing was used to identify point mutations in the coding sequence of Rb, p53, p16, p15 and p21 tumor suppressor genes, and multiplex PCR was used to detect big deletion in p16 and p15 genes. RESULTS: Rb gene point mutation was detected in 74% of retinoblastoma and p16 gene big deletions in 16% of retinoblastoma with or without Rb gene mutation. However, despite polymorphism, no real mutation was detected in p53 or p21 gene in retinoblastoma. CONCLUSION: The evidence from this study suggests that retinoblastoma is resulted exclusively from alterations of genes in Rb pathway.

Cell Cycle Proteins↗
PubMed1999

[Digital subtraction angiography of cerebrum for diagnosis of cavernous sinus fistula and its intravascular treatment].

OBJECTIVE: To evaluate the diagnosis of digital subtraction angiography (DSA) of cerebral arteries and the intravascular treatment for carotid artery-cavernous sinus fistula (CCF) mainly manifesting as pulsating exophthalmos. METHODS: Digital subtraction angiography (DSA) of cerebral arteries was carried out for 15 patients with pulsating exophthalmos. Of them, detectable balloon and tungsten filament microcoil were used for intravascular embolism treatment in 12 cases, and the 3 cases with CCF of the branch of external carotid artery were not treated. RESULTS: Of the 15 cases, 12 were fallen in the CCF of high flow type of unilateral internal carotid artery, and 3 in the CCF of low flow type of unilateral external carotid artery. The symptoms and signs of intravascular embolism disappeared after treatment in 11 cases. CONCLUSION: Cerebral artery DSA and intravascular therapy are the ideal methods for the diagnosis and treatment of CCF mainly manifesting as pulsating exophthalmos.

Adult↗