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Biomedical subjects

Hui Xu

Publications and source records attributed to Hui Xu.

At least 109 records · Page 6Linked to original sources
PubMed2004

Tempol lowers blood pressure and sympathetic nerve activity but not vascular O2- in DOCA-salt rats.

This study tested the hypothesis that depressor responses caused by tempol are not associated with reductions in vascular O2- levels in urethane-anesthetized deoxycorticosterone acetate (DOCA)-salt hypertensive rats. We compared the effects of intravenous (IV) administration of tempol, apocynin, superoxide dismutase-polyethylene glycol (PEG-SOD), and SOD on mean arterial blood pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA). In DOCA-salt rats, tempol (30 to 300 micromol/kg) dose-dependently decreased RSNA, MAP, and HR. Tempol (300 micromol/kg) decreased MAP from 140+/-5 to 83+/-4 mm Hg (P<0.05). HR decreased from 435+/-15 to 390+/-12 bpm (P<0.05). RSNA was reduced by 54%+/-6% from baseline. However, in the same rats, tempol did not reduce dihydroethidium-induced fluorescent signals in the aorta and vena cava. Apocynin (200 micromol/kg) did not lower MAP (142+/-5 mm Hg versus 140+/-6 mm Hg) or HR (428+/-15 bpm versus 420+/-13 bpm) and apocynin did not potentiate depressor responses caused by tempol. PEG-SOD (10 000 U/kg, bolus or 5000 U/kg bolus followed by a 30-minutes infusion of 500 U/kg/min) or SOD (25 000 U/kg, bolus or 10 000 U/kg bolus followed by a 30-minutes infusion of 1000 U/kg per minute) did not alter MAP or HR. It is concluded that depressor responses and decreases in HR and RSNA caused by acute tempol treatment are caused by direct sympathetic nerve activity inhibition that is not accompanied by SOD-mimetic action in the aorta or vena cava.

Acetophenones↗
PubMed2004

Origin of the murine implantation serine proteinase subfamily.

The S1 serine protease family is one of the largest gene families known. Within this family there are several subfamilies that have been grouped together as a result of sequence comparisons and substrate identification. The grouping of related genes allows for the speculation of function for newly found members by comparison and for novel subfamilies by contrast. Analysis of the evolutionary patterns of genes indicates whether or not orthologs are likely to be identified in other species as well as potentially indicating that hypothesized orthologs are in fact not. Looking at subtle differences between subfamily members can reveal intricacies about function and expression. Previously, we have described genes encoding two novel serine proteinases, ISP1 and ISP2, which are most closely related to tryptases. The ISP1 gene encodes the embryo-derived enzyme strypsin, which is necessary for blastocyst hatching and invasion in vitro. Additionally both ISP1 and ISP2 are co-expressed in the endometrial gland during the time of hatching, suggesting that they may also both participate in zona lysis from within the uterine lumen. Here, we demonstrate that the ISPs are tandemly linked within the tryptase cluster on 17A3.3. We suggest that remarkable similarities within the 5'-untranslated and first intron regions of ISP1 and ISP2 may explain their intimate co-regulation in uterus. We also suggest that ISP genes have evolved through gene duplication and that the ISP1 gene has also begun to adopt an additional new function in the murine preimplantation embryo.

Amino Acid Sequence↗
PubMed2004

New aminocoumarin antibiotics formed by a combined mutational and chemoenzymatic approach utilizing the carbamoyltransferase NovN.

Five new aminocoumarin antibiotics were produced by a combined mutational and chemoenzymatic approach. For this purpose, the 3"-carbamoyltransferase NovN from the novobiocin producer Streptomyces spheroides was overexpressed in the heterologous host S. lividans as an N-terminal His(6) fusion protein and purified by nickel affinity chromatography. Five different 3"-unsubstituted aminocoumarin derivatives were isolated from mutants of the clorobiocin producer S. roseochromogenes, carrying single or multiple gene defects. All five compounds were readily accepted as substrates by NovN, and the 3"-carbamoylated products were isolated on a preparative scale. Their structures were elucidated by (1)H-NMR and mass spectroscopy, and their inhibitory activity on gyrase in vitro as well as their antibacterial activity was determined. The results give further insight into the structure-activity relationships of aminocoumarin antibiotics.

Animals↗
PubMed2004

An evaluation of the curve of Spee in the maxilla and mandible of human permanent healthy dentitions.

STATEMENT OF PROBLEM: The characteristics of the curve of Spee in the mandibular arch have been extensively investigated. However, few studies have examined the characteristics of the curve of Spee in the maxillary arch. PURPOSE: The purpose of this study was to examine the differences in the curve of Spee between the maxillary and mandibular arches. The effects of gender on the curve of Spee were also investigated. Material and methods Fifty Japanese adults (25 men and 25 women) with permanent healthy dentitions participated. Standardized digital pictures of the right side of maxillary and mandibular dental casts were made with a digital camera. The cusp tips of the molars, premolars, and canines of the maxilla and mandible were identified. The radius and the depth of the curve of Spee were measured on the dental casts by means of computer software (Occlcircle). The Mann-Whitney test and the Wilcoxon signed rank test were used to test the statistical significance (alpha=.05). RESULTS: The curve of Spee showed a mean radius of approximately 106.4 mm in the maxillary arch and 83.4 mm in the mandibular arch. Radii of the curves of Spee in the maxillary arch were significantly larger than those in the mandibular arch (P <.0001) and had a depth of approximately 1.6 mm in the maxillary arch and 1.9 mm in the mandibular arch. The depth of the curve of Spee in the mandibular arch was significantly deeper than that in the maxillary arch (P =.0326). CONCLUSIONS: The curve of Spee was not influenced by the gender of the subjects investigated. The shape of the curve of Spee in the maxillary arch was significantly flatter than that in the mandibular arch.

Adult↗
PubMed2004

Oncolytic vaccinia virus expressing the human somatostatin receptor SSTR2: molecular imaging after systemic delivery using 111In-pentetreotide.

Oncolytic vaccinia viruses (VV) have demonstrated tumor specificity, high levels of transgene expression, and anti-tumor effects. The ability to visualize vector biodistribution noninvasively will be necessary as gene therapy vectors come to clinical trials, and the creation of a VV that can both treat tumors and permit noninvasive imaging after systemic delivery is therefore an exciting concept. To facilitate imaging, a VV expressing the human somatostatin receptor type 2 (SSTR2) was created. Cells infected with the SSTR2-expressing VV or controls were incubated with the somatostatin analog 111In-pentetreotide with or without an excess of nonradiolabeled pentetreotide. The SSTR2-infected cells bound 111In-pentetreotide sixfold more efficiently than control virus-infected cells and this binding was specifically blocked by nonradiolabeled pentetreotide. Nude mice bearing subcutaneous murine colon CA xenografts were injected intraperitoneally with the SSTR2-expressing VV or control VV. After 6 days, mice were injected with 111In-pentetreotide and imaged. Mice were sacrificed and organs collected and counted in a gamma counter. The uptake of radioactivity in tumors and normal tissues (percentage injected dose per gram) and tumor-to-normal tissue ratios were determined. Tumors infected with the SSTR2-expressing VV accumulated significantly higher concentrations of radioactivity compared to tumors in animals receiving the control virus. SSTR2-infected tumors were visible on imaging 6 days after VV injection and could be visualized for up to 3 weeks post-viral injection using repeat injections of 111In-pentetreotide. This reporter gene imaging strategy could be a very effective method to visualize vector distribution, expression, and persistence over time and enhances the potential of VV as a novel anti-cancer therapeutic.

Animals↗
PubMed2004

Multichannel electrogastrography (EGG) in normal subjects: a multicenter study.

The aim of this study was to record gastric myoelectric activity using multichannel electrogastrography (EGG) and to determine if there are differences due to age, gender, body mass, and study location. In 61 normal subjects from four centers, fasting multichannel EGG was recorded for 1 h, followed by two 1-h postprandial recordings after a test meal. Variables assessed included dominant frequency (DF) and its power, percentage time in 2- to 4-cpm frequency, and percentage slow-wave coupling (%SWC). There were no significant differences in EGG parameters with respect to gender or age. Subjects with a BMI > 25 had a decrease in the absolute DF power but a similar increase in the postprandial DF power. Subjects with a BMI > 25 had a postprandial decrease in the %SWC compared to those with a BMI < 25. There was a decrease in postprandial %SWC in European/Asian centers compared to American centers. In conclusion, multichannel EGG provides assessment of electrical slow-wave coupling in addition to determining dominant frequency, power, and percentage normal rhythm. This multicenter study of normal subjects shows similar multichannel EGG values among different genders and ages. Body mass and ethnicity may impact on some of the EGG values.

Adolescent↗
PubMed2004

Development of dermatitis in CD18-deficient PL/J mice is not dependent on bacterial flora, and requires both CD4+ and CD8+ T lymphocytes.

CD18-deficient PL/J mice develop dermatitis characterized by hyperkeratosis, and a mixed dermal and epidermal inflammatory infiltrate. The development of this disease requires low-level CD18 expression and at least two PL/J loci. Currently, the mechanisms by which decreased beta(2) integrin expression on leukocytes promotes skin inflammation in PL/J mice are unknown. In these studies, we investigated the role of microbial infection and T lymphocytes in the pathogenesis of this disease. We found that germ-free CD18(-/-) PL/J mice developed dermatitis indistinguishable from that of mice raised in pathogen-free conditions. Adoptive transfer of CD18(-/-) PL/J splenocytes into skin disease-resistant CD18(+/-) PL/J mice failed to induce skin inflammation. However, transfer of CD18(+/-) splenocytes blocked the progression and ultimately led to resolution of skin disease in the majority of CD18(-/-) recipients. Depletion of both CD4(+) and CD8(+) T cells mice prior to onset of the disease significantly delayed the appearance of inflammatory skin disease. In contrast, single depletions of these T cells did not inhibit disease development. These studies show that dermatitis in CD18-deficient PL/J mice is not the consequence of infection, does not require bacterial superantigens, and is mediated by both CD4(+) and CD8(+) T lymphocytes. Furthermore, they suggest that one possible mechanism for skin disease development in these mice may involve the absence or dysfunctional activity of a regulatory T cell population. These mice may therefore be useful in identifying potential mechanisms of pathogenesis and genetic predisposition in human inflammatory skin diseases.

Adoptive Transfer↗
PubMed2004

The effects of total-body irradiation on the survival and skin wound healing of rats with combined radiation-wound injury.

To investigate the effects of total body irradiation on the healing of skin wounds, rats were irradiated with a (60)Co gamma-ray source, in which single doses ranged from 1 to 8 Gy. After irradiation, two whole-thickness circular skin wounds, 22 mm in diameter and covering 2.5% of the total body surface area, were made immediately on the back of each animal. The average healing time for the simple wound was 18.3 +/- 2.1 days, whereas when the wound was combined with 1, 2, 3, 4, 5, and 6 Gy of radiation, the average wound healing time was delayed by 0.3, 0.8, 1.1, 3.5, 6.2, and 9.5 days, respectively. The average healing time was significantly decreased with irradiation doses exceeding 4 Gy, as compared with the healing time for the simple wound without irradiation (p < 0.05). The statistical results showed that the percentage of the unclosed wound with the increased doses in combined radiation injury was significantly proportional to the recovery time kinetics.

Animals↗
PubMed2004

Grafting of deproteinized bone particles inhibits bone resorption after maxillary sinus floor elevation.

OBJECTIVES: To evaluate the value of deproteinized bone particles on bone resorption in the augmented space after maxillary sinus floor elevation in rabbits. MATERIAL AND METHODS: A total of 20 rabbits underwent bilateral grafting, using blood clots (control group) and deproteinized bone particles (experimental group), and followed with histologic and histomorphometric analysis. RESULTS: Two weeks after grafting, the augmented space was almost completely obliterated by both newly formed bone and fibrous connective tissue in the control group. Some osteoclasts were found on the surface of newly formed bone, especially near the elevated sinus membrane. In the experimental group, newly formed bone was found along the elevated sinus membrane, the cortical wall of the augmented space, and the surface of deproteinized bone particles near the cortical wall. Some osteoclasts were found along the deproteinized bone particles and a few adhered to the surface of the newly formed bone. Eight to 10 weeks after implantation in the control group, most of the newly formed bone had been resorbed. In the experimental group, newly formed bone was found in most parts of the convex augmented space. Histomorphometrical analysis showed that the augmented height was significantly higher in the experimental group than in the control group at all evaluation times. Bone area was significantly higher in the experimental group than in the control group at 6, 8, and 10 weeks after implantation. The area of grafted deproteinized bone particles did not change significantly from 2 to 10 weeks. CONCLUSION: Slowly resorbed deproteinized bone particles contribute to stable augmentation of the maxillary sinus floor by inhibiting bone resorption.

Animals↗
PubMed2004

Mitochondrial enzymes in schizophrenia.

The responses of brain metabolism and blood flow to stimulation are diminished in the dorsolateral prefrontal cortexes (DLPFCs) of schizophrenic patients. Reductions in mitochondrial enzymes underlie diminished metabolism in several neurodegenerative diseases. Thus, we tested whether reductions in selected mitochondrial enzymes could underlie the changes in schizophrenia. The activities of the pyruvate dehydrogenase complex (PDHC), aconitase, isocitrate dehydrogenase (ICDH), and the alpha-ketoglutarate dehydrogenase complex (KGDHC) were determined on DLPFCs from patients with schizophrenia (n=26) and normal nonpsychiatric disease controls (n=13). The enzyme activities (mU/mg protein; mean +/- SEM) were similar (values for controls and schizophrenic patients, respectively) for PDHC (11.36 +/-1.5, 10.33 +/- 0.8), aconitase (1.06 +/- 0.1, 1.35 +/- 0.2), ICDH (31.70 +/- 2.7, 32.00 +/- 2.6), and KGDHC (2.62 +/- 0.4, 3.09 +/- 0.3). Separate analyses of the patients matched for age or postmortem interval gave similar conclusions. Cognitive dementia rating scores correlated poorly with activities of PDHC, aconitase, ICDH, and KGDHC. In one schizophrenic patient, activity of aconitase was undetectable, and in two others KGDHC activity was very low. Both had low activities of ICDH. A reduced activity of these enzymes in a subgroup is consistent with other data, suggesting that some patients with schizophrenia have abnormalities in brain mitochondria. However, in schizophrenia, unlike a number of neurodegenerative diseases, reductions in the activities of the key mitochondrial enzymes KGDHC and PDHC are not frequent.

Aconitate Hydratase↗
PubMed2004

Transplantation of dermal multipotent cells promotes survival and wound healing in rats with combined radiation and wound injury.

Combined radiation and wound injury occurs after severe nuclear accidents that accompany explosions or nuclear attacks. High doses of ionizing radiation can cause bone marrow aplasia and delay wound healing. Combined radiation and wound injury is very complex and is more difficult to deal with than single injuries. Multipotent stem cells that have self-renewal potential and multilineage differentiation capacity are the relevant cells in regenerative medicine. To determine whether multipotent stem cells can have multiple therapeutic effects in vivo, systemic transplantation of cultured dermal multipotent cells was performed in rats with combined radiation and wound injury. The results showed that dermal multipotent cell transplantation promoted survival and accelerated both hematopoietic recovery and wound healing in rats with combined radiation and wound injury. FISH analysis using a Y-chromosome-specific probe indicated that donor dermal multipotent cells could engraft into recipient skin and bone marrow after transplantation. FACS analysis of the proportions of CD2- and CD25-positive peripheral lymphocytes indicated that dermal multipotent cell transplantation did not induce an obvious activation of allogeneic lymphocytes in vivo in 3 weeks. These data indicate that dermal multipotent cell transplantation may provide a new tool for the treatment of combined radiation and wound injuries.

Animals↗
PubMed2004

Enantiomeric separation of basic drugs with partially filled serum albumin as chiral selector in capillary electrophoresis.

A reliable method is presented for the chiral separation of three basic drugs (mexiletine, chlorpheniramine and propranolol) with serum albumins (human and porcine, HSA and PSA) as chiral selectors by capillary electrophoresis in combination with the partial filling technique. Based on the systematic optimization of operation variables, the chiral separation of mexiletine, chlorpheniramine and propranolol was achieved in the pH 7.4 phosphate buffer by using HSA, PSA and PSA as selectors, respectively. The chiral recognition ability of HSA and PSA was compared. HSA and PSA show a different chiral recognition ability for each of the three drugs. In addition, the association constants between enantiomeric drugs and proteins were determined to be 2.00 and 3.80 x 10(2) M(-1) for mexiletine and HSA, 0.59 and 1.12 x 10(3) M(-1) for chlorpheniramine and PSA, and 0.87 and 1.42 x 10(3) M(-1) for propranolol and PSA. The method for the chiral separation and determination of association constants possesses the advantages of simple performance, effective avoiding of the interference of the UV detection from protein, and lowering of the reagent consumption.

Adrenergic beta-Antagonists↗
PubMed2004

[Effects of high-volume hemofiltration on serum levels of tumor necrosis factor and its receptors in patients with multiple organ dysfunction syndromes].

OBJECTIVE: To investigate whether serum tumor necrosis factor-alpha (TNF-alpha) and its receptors can be removed by high-volume hemofiltration (HVHF) or continuous veno-venous hemofiltration (CVVH). METHODS: The study was performed in 12 multiple organ dysfunstion syndrome (MODS) patients with acute renal failure (ARF). They were randomized to receive either CVVH (n=10) or HVHF (n=8). TNF-alpha and soluble tumor necrosis factor-receptor (sTNF-R1 and sTNF-R2) concentrations were measured in serum by enzyme-linked immunoadsorbent assay (ELISA). RESULTS: Compared with that before the therapy, the average concentrations of plasma creatinine and urea were decreased significantly 8 hours after HVHF or CVVH in MODS patients with ARF (P<0.001). In patients on HVHF, the serum TNF-alpha concentrations were significantly lower 8 hours after treatment (P<0.01) compared with that before treatment, 1 hour and 4 hours after treatment. There were not significant changes in the serum TNF-alpha concentrations in patients on CVVH and the serum sTNF-R1 and sTNF-R2 concentrations in patients on CVVH or HVHF. CONCLUSION: In MODS patients with ARF undergoing HVHF, the serum TNF-alpha concentrations dropped significantly, but the serum sTNF-R1 and sTNF-R2 concentrations do not change significantly. Our study suggests that HVHF may be the better option for the treatment of MODS patients.

Adult↗
PubMed2004

[Effect of lipopolysacharide on the biological features and growth factor secretion power of U937 cell line].

OBJECTIVE: To investigate the effect of lipopolysacharide (LPS) in different concentrations on the biological features and growth factor secretion power of U937 cell line. METHODS: In vitro cultured U937 cells were stimulated by 0 (as control), 0.1, 1.0, 10.0, 50.0 and 100 micro g/ml LPS respectively for 24 hours. Thereafter, the cell proliferation ability was determined by MTT method. The cell apoptosis rate was determined by flow cytometry. The changes in the contents of transforming growth factor beta(1) (TGFbeta(1)) and vascular endothelial growth factor (VEGF) of the supernatant of the cell culture were assessed by ELISA. RESULTS: Apoptosis and TGFbeta(1) secretion could be induced by LPS in dose of 0.1 to 100 micro g/ml when compared with that without LPS challenge (P < 0.05 - 0.01). In detail, LPS in lower dose (0.1, 1.0 and 10.0 micro g/ml) could promote the proliferation of U937 (P < 0.05 - 0.01) but exerted no effect on VEGF secretion. In contrary, LPS in high dose (50 and 100 micro g/ml) could promote VEGF secretion (P < 0.01) but exerted no effects on the proliferation of U937 cells. CONCLUSION: U937 cells could be activated to increase the secretion of TGFbeta(1) by LPS in optimal dose of 0.1 - 10.0 micro g/ml, but the secretion of VEGF could only be promoted by LPS in higher concentration.

Apoptosis↗
PubMed2004

[The effect of recombinant human erythropoietin on postoperative anemia in orthognathic patients].

PURPOSE: To observe the effect of rhEPO on postoperative anemia in orthognathic patients. METHODS: 31 patients had 500-1200 ml blood loss during orthognathic operation, who were divided into two groups randomly, the experiment group and the control group. The patients in the experiment group received rhEPO 6000IU subcutaneously for 3 times in a week and Ferrost sulfatis Et vitamini-medtech 1 tablet per day via oral administration for 12 days after operation, while the patients in the control group only received the same dose of Ferrost sulfatis Et vitamini-medtech. The loss of blood of the patients during operation were estimated and recorded. Their Hb and Hct were mensured before operation, and in the first, third, seventh-twelfth day after operation. RESULTS: In the twelfth day after operation, the Hb and Hct of the patients in the experiment group had a significantly higher increase than that in the control group (P<0.05). CONCLUSIONS: rhEPO combined Ferrost sulfatis Et vitamini-medtech are suitable to apply in orthognathic patients with anemia after operation, which may effectively accelerate the recovery of their anemia, and avoid transfusion of blood.

Adolescent↗
PubMed2004

[Successful tracheal intubation in a child with facial multi-clefts and difficult airway: case report.].

A male patient, aged 7 years, was intended to undergo plastic surgery under general anesthesia with tracheal intubation for his severe facial abnormities as a result of 5, 6, 7 combined facial clefts. Because of his severe facial abnormities and preoperative undetected bilateral antiadoncus, during the period of induction, dyspnoea and dysventilation took place, which were relieved by inserting a medium-sized oropharyngeal airway with difficulty; during euthyphoirally exploring his endolarynx with direct laryngoscope, laryngospasm occurred, which was relieved through inserting airway and pressurizing ventilation; repetitively attempted to blindly insert tracheal intubation through nostril, but failed. Finally, his intubation was achieved by blindly intubating through oral cavity under the assistance of direct laryngoscope.

Anesthesia, General↗