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Biomedical subjects

Min Xu

Publications and source records attributed to Min Xu.

At least 91 records · Page 5Linked to original sources
PubMed2005

Clinical characteristics and mechanism of liver damage in patients with severe acute respiratory syndrome.

BACKGROUND: Abnormal liver function was found in patients with severe acute respiratory syndrome (SARS). This study was undertaken to explore the clinical characteristics and mechanisms of liver damage. METHODS: The serial laboratory data of liver function test and hepatic histological examination from 168 patients with SARS were retrospectively analyzed. RESULTS: The abnormalities of serum alanine aminotransferase (ALT) were 52.5%, 71.8%, 85.7% and 85.2%. The average levels of ALT of the patients were 56.07+/-51.57 U/L, 86.46+/-69.93 U/L, 106.69+/-102.50 U/L and 111.32+/-160.24 U/L, and the average levels of serum albumin were 37.25+/-5.37 g/L, 35.82+/-4.74 g/L, 34.49+/-5.04 g/L, and 34.26+/-4.70 g/L, at the day of admission, the first week, second week, and third week after hospitalization, respectively. Significant correlation was not shown among liver damage, blood oxygen saturation (SaO2), degree of fever, and immune functional disorder in this study. Hepatic histological examination of 4 patients demonstrated that non-specific inflammation existed in the liver. CONCLUSIONS: Liver damage of patients with SARS usually occurs in the early stage of the disease with a high occurrence rate and a prolonged profile, which can be characterized by early, obvious decrease of albumin levels and slightly abnormal levels of ALT. The liver damage induced by SARS seems to be caused by SARS virus directly rather than by low SaO2 or high fever. Hepatotoxic drugs may play a role in increasing the severity of liver damage or prolonging the time of liver function recovery.

Adolescent↗
PubMed2005

[Effects of intervention embolization therapy and intratumor injection with hardener on head and neck gigantic hemangioma].

OBJECTIVE: The goal of this study is to present our experience of transarterial embolization and intratumor injection for the treatment of gigantic hemangioma of the head, face, and neck. METHOD: From 2001 to 2003, 3 patients with gigantic hemangioma were selected to get digital subtraction angiography (DSA) and transarterial embolization and intratumor injection successfully. RESULT: Angiography after embolization showed almost complete obliteration of hemangioma. There were no serious complications such as embolism to other organs and necrosis of a large area in the embolized tissue. Only slight swelling and pain in the embolized area were present. And gradually disappeared by expect and treatment. No recurrence of the symptoms was occurred in a follow-up evaluation of 6- 24 months. CONCLUSION: Using of DSA. transarterial embolization and intratumor injection showed an excellent clinic effect on treatment of hemangioma, reducing the recurrence of the symptoms.

Adult↗
PubMed2005

[Thermal dosimetric study on hyperthermia combined with radiotherapy for deep seated pelvic malignancies].

OBJECTIVE: To ascertain a clinically meaningful thermal dose unit-temperature equivalent minute (TEM) 42.5 degrees C and the relationship between TEM 42.5 degrees C and tumor response rate. METHODS: From August 1998 to December 2002, 49 patients with recurrent or metastatic malignancies in the pelvis were treated with hyperthermia combined with conventional radiotherapy. Direct thermometry with high resistance lead needle was used whenever possible to measure the temperature by inserting Teflon catheter into the tumor. TEM 42.5 degrees C was used as the thermal dose unit and the relationship between TEM 42.5 degrees C and tumor response rate was monitored. RESULTS: There was a positive correlation between response rate TEM 42.5 degrees C and the radiation dose. The tumor volume and number of heat treatment showed no influence on response. CONCLUSION: Both univariate analysis and multivariate logistic regression analysis indicate that there is a positive correlation between the response rate, TEM 42.5 degrees C and the radiation dose. TEM 42.5 degrees C may act as a useful thermal dose unit in the combination of hyperthermia and radiotherapy. To lower the incidence of complications in thermometry, direct thermometry with high resistance lead needle can be used to measure the temperature by inserting Teflon catheter into the deep-seated malignancies.

Adenocarcinoma↗
PubMed2005

[The expression and significance of human beta-defensin 2 in middle ear cholesteatoma epithelium].

OBJECTIVE: To explore the effects of human beta-defensin 2 (hBD-2) in pathologic process of cholesteatoma by observing the expression of hBD-2 and the correlation of hBD-2 and density of Langhans cells(LC) in middle ear cholesteatoma. METHOD: The specimens from 21 cases of acquired middle ear cholesteatoma and 10 cases of external auditory canal skin (EACS) were examined by immunohistochemical method of hBD-2 and Langerhans cells (S-100 positive cells). RESULT: In EACS, hBD-2 staining was faint while in the epithelium of cholesteatoma it was much stronger, there was significant difference between them( P < 0.01). Compared to that in EACS, the number of LC in the epithelium of cholesteatoma was increased. There was a strong correlation between elevated expression of hBD-2 and increased density of LC in the epithelium of cholesteatoma ( P < 0.05). CONCLUSION: hBD-2 may play an important role in the inflammatory status of middle ear cholesteatoma. It maybe display chemotactic activity for LIangerhans cells (LC), and thus serves to link up innate and acquired immunity.

Adolescent↗
PubMed2005

SMYD3-NY, a novel SMYD3 mRNA transcript variant, may have a role in human spermatogenesis.

Identification of genes specifically expressed in adult and fetal testis is important to further our understanding of testis development and function. In this study, a novel SMYD3 transcript variant, termed SMYD3-NY (GenBank Accession No. AY186742), was identified by hybridization of adult and fetal human testis cDNA probes with a human cDNA microarray. SMYD3-NY transcript was expressed at 2.3-fold higher levels in adult human testis than in fetal testis, with a low expression level in human spermatozoa. Bioinformatical analysis showed that SMYD3-NY protein has the SET domain that is involved in histone methyltransferase (HTMase) activity. Southern blotting showed that SMYD3-NY is distributed in several tissues, including testis. In summary, SMYD3-NY is a novel transcript variant of the SMYD3 gene, and SMYD3-NY protein may influence transcriptional regulation during spermatogenesis via HTMase activity.

Adult↗
PubMed2005

[A minimally invasive approach in the treatment of complicated anal fistula through spatium intermuscular of anal sphincter].

OBJECTIVE: To investigate the optimal operative approach for the complicated anal fistula. METHODS: One hundred and ninety-two cases with complicated anal fistula were randomly divided into minimally invasive operation group (through spatium intermuscular of anal sphincter) and fistula resection group. The operation time, bleeding time during and after operation, pain lasting time, healing time of incision, area of anal scar, anal malformation and function and post operative recurrence were observed and compared between the two groups. RESULTS: Compared to those of fistula resection group, the operative time was (36.5+/- 15.3)min, bleeding time during and after operation (2.0+/- 0.5)d, postoperative pain lasting time (1.5+/- 0.5)d, healing time of incision (18.5+/- 5.5)d in minimally invasive operation group. All were shortened (P< 0.05), and the incidence of anal malformation (5.2%, P< 0.01) and partial anal incontinence (2.1%, P< 0.01) was lower. There was no significant difference in postoperative recurrence between the two groups. CONCLUSIONS: The minimally invasive operation through spatium in termuscular of anal sphincter is superior to fistula resection on the management of complicated fistula.

Adult↗
PubMed2005

Application of Bayesian regularized BP neural network model for analysis of aquatic ecological data-a case study of chlorophyll-a prediction in Nanzui water area of Dongting Lake.

Bayesian regularized BP neural network(BRBPNN) technique was applied in the chlorophyll-a prediction of Nanzui water area in Dongting Lake. Through BP network interpolation method, the input and output samples of the network were obtained. After the selection of input variables using stepwise/multiple linear regression method in SPSS 11.0 software, the BRBPNN model was established between chlorophyll-a and environmental parameters, biological parameters. The achieved optimal network structure was 3-11-1 with the correlation coefficients and the mean square errors for the training set and the test set as 0.999 and 0.00078426, 0.981 and 0.0216 respectively. The sum of square weights between each input neuron and the hidden layer of optimal BRBPNN models of different structures indicated that the effect of individual input parameter on chlorophyll-a declined in the order of alga amount > secchi disc depth (SD) > electrical conductivity (EC). Additionally, it also demonstrated that the contributions of these three factors were the maximal for the change of chlorophyll-a concentration, total phosphorus (TP) and total nitrogen (TN) were the minimal. All the results showed that BRBPNN model was capable of automated regularization parameter selection and thus it may ensure the excellent generation ability and robustness. Thus, this study laid the foundation for the application of BRBPNN model in the analysis of aquatic ecological data(chlorophyll-a prediction) and the explanation about the effective eutrophication treatment measures for Nanzui water area in Dongting Lake.

Bayes Theorem↗
PubMed2004

Structure-based design of potent and selective cell-permeable inhibitors of human beta-secretase (BACE-1).

We describe the development of cell-permeable beta-secretase inhibitors that demonstratively inhibit the production of the secreted amino terminal fragment of an artificial amyloid precursor protein in cell culture. In addition to potent inhibition in a cell-based assay (IC50 < 100 nM), these inhibitors display impressive selectivity against other biologically relevant aspartyl proteases.

Amyloid Precursor Protein Secretases↗
PubMed2004

Identification of a small molecule nonpeptide active site beta-secretase inhibitor that displays a nontraditional binding mode for aspartyl proteases.

A small molecule nonpeptide inhibitor of beta-secretase has been developed, and its binding has been defined through crystallographic determination of the enzyme-inhibitor complex. The molecule is shown to bind to the catalytic aspartate residues in an unprecedented manner in the field of aspartyl protease inhibition. Additionally, the complex reveals a heretofore unknown S(3) subpocket that is created by the inhibitor. This structure has served an important role in the design of newer beta-secretase inhibitors.

Acetamides↗
PubMed2004

Percoll gradient-centrifuged capacitated mouse sperm have increased fertilizing ability and higher contents of sulfogalactosylglycerolipid and docosahexaenoic acid-containing phosphatidylcholine compared to washed capacitated mouse sperm.

Although Percoll gradient centrifugation has been used routinely to prepare motile human sperm, its use in preparing motile mouse sperm has been limited. Here, we showed that Percoll gradient-centrifuged (PGC) capacitated mouse sperm had markedly higher fertilizing ability (sperm-zona pellucida [ZP] binding and in vitro fertilization) than washed capacitated mouse sperm. We also showed that the lipid profiles of PGC capacitated sperm and washed capacitated sperm differed significantly. The PGC sperm had much lower contents of cholesterol and phospholipids. This resulted in relative enrichment of male germ cell-specific sulfogalactosylglycerolipid (SGG), a ZP-binding ligand, in PGC capacitated sperm, and this would explain, in part, their increased ZP-binding ability compared with that of washed capacitated sperm. Analyses of phospholipid fatty acyl chains revealed that PGC capacitated sperm were enriched in phosphatidylcholine (PC) molecular species containing highly unsaturated fatty acids (HUFAs), with docosahexaenoic acid (DHA; C22: 6n-3) being the predominant HUFA (42% of total hydrocarbon chains of PC). In contrast, the level of PC-HUFAs comprising arachidonic acid (20:4n-6), docosapentaenoic acid (C22:5n-6), and DHA in washed capacitated sperm was only 27%. Having the highest unsaturation degree among all HUFAs in PC, DHA would enhance membrane fluidity to the uppermost. Therefore, membranes of PGC capacitated sperm would undergo fertilization-related fusion events at higher rates than washed capacitated sperm. These results suggested that PGC mouse sperm should be used in fertilization experiments and that SGG and DHA should be considered to be important biomarkers for sperm fertilizing ability.

Animals↗
PubMed2004

Interparticle interactions in agglomerates of alpha-Fe2O3 nanoparticles: influence of grinding.

We have chemically prepared a sample of antiferromagnetic alpha-Fe2O3 nanoparticles by a gel-sol technique. Mössbauer spectra of the as-prepared sample showed that superparamagnetic relaxation was suppressed due to strong magnetic interparticle interactions even at room temperature. However, subsequent grinding of the sample by hand in a mortar for some minutes resulted in fast superparamagnetic relaxation of some of the particles. The effect was even more dramatic if the alpha-Fe2O3 powder was ground for a longer time or together with nonmagnetic eta-Al2O3 nanoparticles. Similar effects were found after low-energy ball milling. Thus it is found that the agglomeration of the nanoparticles during preparation under wet conditions results in strong magnetic interparticle interaction, but a relatively gentle mechanical treatment is sufficient to break up the agglomerates, resulting in much weaker interactions. We show that these effects can also be seen when a soil sample containing magnetic nanoparticles is ground.

Journal Article↗
PubMed2004

[Effects of continuous early enteral nutrition on the gut barrier function in dogs with acute necrotizing pancreatitis].

OBJECTIVE: To evaluate the effects of continuous early enteral nutrition on the gut barrier function in acute necrotizing pancreatitis (ANP). METHODS: Thirty mongrel dogs underwent laparotomy and 5% mixed solution of sodium taurocholate with trypsin was infused into the pancreatic ducts so as to induce model of ANP. Permanent duodenal and jejunal fistulas were retained. Then the 30 dogs were randomly divided into 6 groups of 5 dogs: total parenteral nutrition (TPN) group, normal saline (NS) group, duodenal nutrison multifibre (DN) group, duodenal PEPTI-2000Varient (DP) group, jejunal nutrison multifibre (JN) group, and jejunal PEPTI-2000Varient (JP) group, the last 4 groups being called enteral nutrition (EN) group together. Infusion of nutritional solutions was performed via the duodenal or jejunal fistulas, beginning 24 hours after the operation and lasting for 5 days. The levels of endotoxin and D-(-)-lactate in the peripheral plasma were measured every day. On the days 2 and 5 after the operation test solution to measure the enteral permeability, containing lactulose and mannitol, was infused via the fistulas and then urine within 6 hours thereafter was collected to detect the concentrations of lactulose and mannitol and calculate the lactulose/mannitol ratio. Seven days after the operation the dogs were killed to take the pancreas and intestines to be examined by microscopy. Feces was collected. ERIC-PCR fingerprint method was used to examine the structure and distribution of ERIC series of the microbial communities in the gut. RESULTS: The plasma D-(-)-lactate of the NS group gradually increased and peaked on the 5th day after the operation, and that of the TPN group gradually increased too, however, lower than that of the NS group at any time points and was significantly lower on the 5th day (P < 0.05). The plasma D-(-)-lactate of the EN groups increased first and then decreased and was lower than those of the TPN and NS groups with significant differences on the 4th and 5th days (all P < 0.05). Five days after the operation the lactulose/mannitol ratio decreased in every groups and with significant differences between the EN groups and TPN and NS groups and between the TPN and NS groups (all P < 0.05). The plasma endotoxin level increased in every groups, however, the endotoxin levels of the EN groups at any time points were all lower than those of the TPN group and much more lower than those in the NS group with significant differences between the EN groups and TPN group and NS group on specific days after operation (all P < 0.05). The pathological changes of the intestinal mucosa were more severe in the NS group than in the TPN group, and much more severe than in the EN groups. The makeup and distribution of intestinal microbial in the EN groups were similar to those of the normal dogs. However, the makeup and distribution of intestinal microbial in the TPN groups were quite different from those of the normal dogs. CONCLUSION: EN helps maintain gut mucosal barrier, decreases endotoxin translocation, and decreases the extent of mucosal atrophy in ANP.

Animals↗
PubMed2004

CD154 signaling regulates the Th1 response to herpes simplex virus-1 and inflammation in infected corneas.

Approximately 7 days after HSV-1 corneal infection, BALB/c mice develop tissue-destructive inflammation in the cornea termed herpes stromal keratitis (HSK), as well as periocular skin lesions that are characterized by vesicles, edema, and fur loss. CD4(+) T cells and Th1 cytokines contribute to both the immunopathology in the cornea and the eradication of viral replication in the skin. We demonstrate that disruption of CD40/CD154 signaling does not impact the initial expansion of CD4(+) T cells in the draining lymph nodes, but dramatically reduces the persistence and Th1 polarization of these cells. Despite the reduced Th1 response, CD154(-/-) mice developed HSK and periocular skin disease with similar kinetics and severity (as assessed by clinical examination) as wild-type (WT) mice. However, when the composition of the inflammatory infiltrate was examined by flow cytometric analysis, CD154(-/-) mice exhibited significantly fewer CD4(+) and CD8(+) T cells and neutrophils than WT mice at the peak of HSK. Moreover, CD4(+) T cells from infected corneas of CD154(-/-) mice produced significantly less IFN-gamma than those of WT mice when stimulated with viral Ags in vitro. The IFN-gamma production of cells from infected corneas of WT mice was not affected by addition of anti-CD154 mAb to the stimulation cultures. This suggests that CD154 signaling is required at the inductive phase, but not at the effector phase, of the Th1 response within the infected cornea. We conclude that local disruption of CD40/CD154 signaling is not likely to be a useful therapy for HSK.

Animals↗
PubMed2004

A signal-arrest-release sequence mediates export and control of the phage P1 endolysin.

The Lyz endolysin of bacteriophage P1 was found to cause lysis of the host without a holin. Induction of a plasmid-cloned lyz resulted in lysis, and the lytic event could be triggered prematurely by treatments that dissipate the proton-motive force. Instead of requiring a holin, export was mediated by an N-terminal transmembrane domain (TMD) and required host sec function. Exported Lyz of identical SDS/PAGE mobility was found in both the membrane and periplasmic compartments, indicating that periplasmic Lyz was not generated by the proteolytic cleavage of the membrane-associated form. In gene fusion experiments, the Lyz TMD directed PhoA to both the membrane and periplasmic compartments, whereas the TMD of the integral membrane protein FtsI restricts Lyz to the membrane. Thus, the N-terminal domain of Lyz is both necessary and sufficient not only for export of this endolysin to the membrane but also for its release into the periplasm. The unusual N-terminal domain, rich in residues that are weakly hydrophobic, thus functions as a signal-arrest-release sequence, which first acts as a normal signal-arrest domain to direct the endolysin to the periplasm in membrane-tethered form and then allows it to be released as a soluble active enzyme in the periplasm. Examination of the protein sequences of related bacteriophage endolysins suggests that the presence of an N-terminal signal-arrest-release sequence is not unique to Lyz. These observations are discussed in relation to the role of holins in the control of host lysis by bacteriophage encoding a secretory endolysin.

Amino Acid Sequence↗
PubMed2004

Identification of a specific self-reactive IgM antibody that initiates intestinal ischemia/reperfusion injury.

Reperfusion injury of ischemic tissue represents an acute inflammatory response that can cause significant morbidity and mortality. The mechanism of injury is not fully elucidated, but recent studies indicate an important role for natural antibody and the classical pathway of complement. To test the hypothesis that injury is initiated by specific IgM, we have screened a panel of IgM-producing hybridomas prepared from peritoneal cells enriched in B-1 cells. One clone, CM22, was identified that could restore pathogenic injury in RAG-1(-/-) mice in an intestinal model of ischemia/reperfusion (I/R). In situ activation of the classical pathway of complement was evident by deposition of IgM, complement C4, and C3 in damaged tissue after passive transfer of CM22 IgM. Sequence analysis of CM22 Ig heavy and light chains showed germ-line configurations with high homology to a V(H) sequence from the B-1 repertoire and a V(K) of a known polyreactive natural IgM. These data provide definitive evidence that I/R injury can be initiated by clonally specific natural IgM that activates the classical pathway of complement. This finding opens an avenue for identification of I/R-specific self-antigen(s) and early prevention of injury.

Animals↗
PubMed2004

A spermatogenesis-related gene expression profile in human spermatozoa and its potential clinical applications.

Spermatogenesis is an essential stage in the human reproductive process. In a previously study aiming to determine which genes might be involved in spermatogenesis, we compared the gene expression profiles of adult and fetal testes by hybridizing cDNA probes prepared from adult and fetal testes to membranes dotted with gene clones derived from a commercial human testis library. We identified 266 differentially expressed genes that showed higher expression levels in adult testes, indicating their potential roles in spermatogenesis. In the present study, we applied the same cDNA microarray technique to the analysis of gene expression in the spermatozoa of normal fertile men and found 149 genes that were expressed at higher levels in adult testis. A further study of five sperm motility-related genes selected from this profile by real-time PCR revealed that there was significant difference in the expression levels of two genes ( TPX-1, testis-specific protein 1 and LDHC, lactate dehydrogenase C, transcript variant 1) between normal ( n=29) and motility impaired ( n=24) semen samples, indicating that these genes are involved in sperm function. Our results demonstrated that spermatogenesis-related gene profiling could help to assess sperm quality in humans, and further study of these genes will help us to elucidate the mechanisms involved in spermatogenesis and diseases relating to human infertility.

A Kinase Anchor Proteins↗