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Biomedical subjects

Y M Xu

Publications and source records attributed to Y M Xu.

At least 19 recordsLinked to original sources
PubMed2006

Reduced semen quality in chronic prostatitis patients that induce the release of apoptotic protein Omi/HtrA2 from spermatozoa.

The relationship between chronic prostatitis and fertility has been disputed for many years. Several groups have shown infection and autoimmune response against prostate antigens could have a deleterious effect on semen quality and fertility. This study was conducted to test the hypothesis that Omi/HtrA2-induced apoptosis in chronic prostatitis could be a mechanism underlying the observed clinical benefit. The Omi/HtrA2 serine protease is a nuclear-encoded mitochondrial protein, which can be released from mitochondria into the cytosol after apoptosis stimuli, inducing apoptosis in caspase-dependent and independent manners. Forty-one patients diagnosed as suffering from chronic prostatitis were included. Healthy normal individuals were included as controls. Human spermatozoa in the semen were purified by Percoll-gradient technique to separate the seminal plasma and other round cells. Measurements for sperm concentration, motility, morphology, proinflammatory cytokines, Omi/HtrA2 mRNA and protein levels in spermatozoa of chronic protatitis patients, were performed accordingly. Significantly increased levels of proinflammatory cytokines were detected in seminal plasma from these prostatitis patients. Omi/HtrA2 mRNA and protein levels were significantly higher in prostatitis men than in normal men. This study shows that chronic prostatitis patients present important alterations in their semen quality parameters, Omi/HtrA2 mRNA and protein levels of spermatozoa. We speculate that the inflammatory process involved may affect male fertility by release of proapoptotic protein Omi/HtrA2.

Adolescent↗
PubMed2006

One-step preparation of MgO hollow spheres and hexagonal cylinders via Zn template.

Polycrystalline hollow spheres and single crystalline hexagonal cylinders of MgO have been fabricated by chemical vapor deposition using ZnO and Mg as the starting materials. The Zn produced during the chemical reaction serves as template material, and vaporization of which leads to the formation of the hollow structures. The presence of trace amount of Si in the source material is identified to be critical for the existence of the stable MgO hollow structures, which otherwise would be damaged during the Zn template removal process. The same principle can be readily adopted in many other material systems and result a variety of hollow structures for catalyst, sensor and medical applications.

Magnesium Oxide↗
PubMed2005

Antibody response to four secretory proteins from Mycobacterium tuberculosis and their complex antigen in TB patients.

OBJECTIVE: To evaluate antibody responses to a panel of four protein antigens secreted from Mycobacterium tuberculosis, CFP-21, ESAT-6, MPT-63 and MPT-64, and their complex antigen. DESIGN: Seventy-eight samples of serum and cerebral spinal fluid were tested by ELISA. RESULTS: Serum IgM antibody positive rates of protein antigens CFP-21, ESAT-6, MPT-63 and MPT-64 and their multi-antigen complex were respectively 34.6%, 60.3%, 52.6%, 78.2% and 96.2%; IgG antibody positive rates were respectively 46.2%, 64.1%, 93.6%, 57.7% and 84.6%. The specificity of the antibodies to the four proteins secreted from M. tuberculosis and its mixture antigen was 100%; sensitivity to the multi-antigen complex was higher than for the four single antigens. Among the IgM positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6, MPT-63 and MPT-64 were significant (P < 0.01); among the IgG positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6 and MPT-64 were significant (P < 0.01). Although the IgG positive rate for MPT-63 was higher than for the multi-antigen complex, the difference was not significantly different (P > 0.05). CONCLUSION: These findings indicate that the multi-antigen complex composed of CFP-21, ESAT-6, MPT-63 and MPT-64 may be useful in the diagnosis of TB.

Adult↗
PubMed2001

Lewis base effects in the Baylis-Hillman reaction of imines with cyclohex-2-en-1-one and cyclopent-2-en-1-one.

In the Baylis-Hillman reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one or cyclopent-2-en-1-one, we found that, in the presence of a catalytic amount of DMAP, the Baylis-Hillman reaction can be greatly accelerated to give the normal Baylis-Hillman adduct 1 or 3 in good or very high yields: moreover, using PBu3 as a Lewis base in the reaction of N-benzylidene-4-methylbenzenesulfonamide with cyclopent-2-en-1-one, the normal Baylis-Hillman adducts 3 could be obtained in very high yields within 5 h, however, using PBu3 or DBU as a Lewis base in the reaction of N-benzylidene-4-methyl-benzenesulfonamide with cyclohex-2-en-1-one, beside the normal Baylis-Hillman adduct 1 abnormal Baylis-Hillman adduct 3-aryl-2-[(4-methylphenyl)sulfonyl]-2-azabicyclo[2.2.2]octan-5-one 2 was formed at the same time; the substituent's effects were also examined.

Journal Article↗
PubMed2001

Seven new sesquiterpene glycosides from the root bark of Dictamnus dasycarpus.

From the water-soluble constituents of the root bark of Dictamnus dasycarpus, six new eudesmane-type sesquiterpene glycosides, dictamnosides H-M (1-6), and a new trinorguaiane-type sesquiterpene glycoside, dictamnoside N (7), together with four known sesquiterpene glycosides, dictamnosides A (8), B (9), D (10), and G (11), were isolated. Their structures were elucidated by spectroscopic analyses and chemical evidence. In vitro tests for immunological activity showed dictamnoside A (8) to possess remarkable activity in stimulating the proliferation of T-cells.

Animals↗
PubMed2001

Enhanced continent mechanism of tapered ileum by extramural support from the pouch and abdominal walls: a preliminary report of a clinical study.

PURPOSE: We constructed a reliable continent tube that is easy to catheterize and surgically simple. MATERIALS AND METHODS: Eight patients with bladder cancer underwent a procedure in which ileal segment was tapered as an efferent tube, of which a part was placed between the back surface of the rectus muscle and the ileal pouch wall. The internal orifice of the tapered ileum was anastomosed to the ileal pouch and its external orifice was anastomosed to the umbilicus. Urodynamic and radiological studies were done postoperatively in 7 cases. RESULTS: The stoma was easily catheterized with a 16Fr catheter in all cases. One patient died of heart disease 55 days postoperatively, while 6 of the remaining 7 were completely continent day and night. Urodynamic study of the efferent tubes showed that maximum close pressure with the pouch full was significantly higher than with the pouch empty (p <0.001). Retrograde radiography of the efferent tubes demonstrated perfect canalization without stenosis. CONCLUSIONS: This study indicates that the continent mechanism of tapered ileum may be greatly enhanced by fixing it between the abdominal and pouch walls. This maneuver also provides easy catheterization and surgical simplicity.

Abdominal Muscles↗
PubMed2000

Free radical scavenging and inhibition of lipid peroxidation by magnesium lithospermate B.

AIM: To study the effect of magnesium lithospermate B (MLB) on the lipid peroxidation and on its free radical scavenging activity. METHODS: MLB was incubated in rat tissue homogenate or in a free radical generating system. MLB induced inhibition of lipid peroxidation and its scavenging activity on superoxide anions and hydroxyl radicals was studied using colorimetric estimation. RESULTS: MLB inhibited the lipid peroxidation induced by either an auto-oxidant or Fe2+/VitC in vitro, in the liver homogenate, the inhibitory rate of MLB (10 mg/L) being 69.2% and 57.7%, respectively. MLB (25 and 50 mg/kg) decreased the amount of thiobarbituric acid reactive substances (TBARS) in rat serum, liver, kidney, and heart. However, it did not inhibit the lipid peroxidation of brain homogenate ex vivo. MLB scavenged superoxide anions generated from xanthine/xanthine oxidase system and iron-dependent hydroxyl radicals. CONCLUSION: MLB is an inhibitor of lipid peroxidation and scavenge superoxide anions and hydroxyl radicals both in vitro and ex vivo.

Animals↗
PubMed2000

Effects of magnesium lithospermate B on aggregation and 5-HT release in rabbit washed platelets.

AIM: To study the effects and mechanism of magnesium lithospermate B(MLB) on rabbit platelet aggregation and 5-HT release. METHODS: The platelet aggregation was determined by Born's method. Release of serotonin (5-HT) and formation of thromboxane A2 (TXA2) were measured by fluorophotometry and radioimmunoassay (RIA) respectively. Cytoplasmic free Ca2+ concentration ([Ca2+]i) in platelets was measured by Fura 2-AM fluorescence technique. RESULTS: In washed platelets, thrombin (200 U/L) or arachidonic acid (AA) (30 mumol/L)-induced aggregation was inhibited by MLB 50-800 mg/L in a concentration-dependent manner. In addition, MLB had more inhibitory effects on platelet aggregation in the absence of extracellular calcium with IC50 of 102 mg/L than in the presence of CaCl2 1 mmol/L with IC50 of 194 mg/L. MLB concentration-dependently decreased the thrombin-activated release of 5-HT, whereas it did not affect the formation of TXA2 in platelets. Furthermore, MLB not only inhibited the rise of [Ca2+]i in thrombin stimulated platelets, but decreased the [Ca2+]i in resting platelets. CONCLUSION: MLB inhibited the aggregation and 5-HT release in rabbit platelets and it is probably by attenuating intracellular calcium concentration.

Animals↗
PubMed1999

[Diagnosis of skull base dieases using three dimensional computed tomography]

OBJECTIVE:To explore the value of three-dimensional (3D) computed tomography (CT) to diseases of the skull base.METHODS:Twenty-five cases with various skull base diseases were examined with 3D CT.All cases received surface shaded display (SSD) method for reconstruction and analysis of 3D reconstruction images in showing the change of skull base bones.RESULTS:In 4 cases with skull base fractures,3D CT demonstrated the fracture lines which were not showed by skull plain films,and provided more informations than those in axial scans.In 15 cases with skull base diseases and 6 cases with trigeminal neuralgia,3D CT helped plan the preoperative approach or the postoperative follow up evaluation,treatment. CONCLUSION:3D CT which based on two dimensional CT scan was very useful for skull baseimaging.

Journal Article↗
PubMed1999

Enhanced continent mechanism of tapered ileum by extramural support from pouch-abdominal wall: an experimental study in dogs.

PURPOSE: To construct a reliable continent tube, which is easy to catheterize, we created and evaluated a new continent cutaneous diversion using a tapered ileum combined with extramural support from the pouch-abdominal wall. MATERIALS AND METHODS: Six dogs underwent a procedure in which two ileal segments were tapered and anastomosed to the ileal pouch. One of the segments (continent) was placed between the back surface of the rectus muscle and the wall of the ileal pouch creating a continent tube. The other segment (control) was brought out into the abdominal skin directly without any support from the pouch-abdominal wall. Urodynamic and radiological studies were carried out postoperatively in all dogs. RESULTS: In the continent tubes, the maximum closure pressure with a full pouch was significantly higher than those with an empty pouch (p<0.01). The maximum closure pressures of the continent tubes were significantly higher than those of the control tubes when the pouch was empty (p<0.01). The leak point pressures of the continent tubes were significantly higher than those of the control tubes (p<0.001). In all dogs, the retrograde radiogram of the continent tubes showed perfect canalization without stenosis. CONCLUSION: This study suggests that the continent mechanism of tapered ileum can be greatly enhanced by fixing it between the abdominal and pouch walls, also allowing easy catheterization in contrast to the submucosal tunnel technique.

Abdominal Muscles↗
PubMed1998

A drug-lipid interaction model: atropine induces interdigitated bilayer structure.

X-ray diffraction and fluorescence methods have been carried out to examine the effects of a drug, atropine, on the structure of model membranes: dipalmitoylphosphatidylglycerol(DPPG) multilamella vesicles(MLVs). A structural analysis by small angle x-ray diffraction shows that, with incorporation of atropine, the lamella repeating period of DPPG MLV is decreased from 5.89 nm to 4.52 nm. Using fluorescence probe 1,6-diphenyl-1,3,5-hexatriene(DPH) we find that the fluorescence intensity of DPH reduces largely at a narrow scope of atropine concentration. The experiments of fluorescence polarization of n-(9-anthroyloxyl)-stearic acid (nAS) and 16-(9-anthroyloxyl)-palmiticacid (16AP) discover that the normal polarization gradient almost disappears in DPPG/atropine system. By colligating the above results, we can draw a conclusion that atropine induces the transition from non-interdigitated to interdigitated stricture of DPPG vesicles in gel phase, which provides a sound model of drug-lipid interaction.

Atropine↗
PubMed1996

Total replacement of urethral mucosa with oral mucosa in dogs.

PURPOSE: If the urethral mucosa is replaced by another mucosa, urethral recurrence might decrease in patients who undergo neobladder construction for bladder cancer. We determined whether such replacement is possible. MATERIALS AND METHODS: Six dogs underwent an operation consisting of a longitudinal urethral incision at its full length and immediate closure. In 6 other dogs, after the urethral mucosa was totally removed, a tubularized sublingual mucosa was closely set inside the urethral lumen. Postoperatively, the urinary stream and external meatus were observed every day. To measure urine leakage, a 10-minute pad test was performed once a month. All dogs were sacrificed 3 to 12 weeks after the operation for histological examination of the urethra. The excised urethras were examined with a 12F catheter for urethral patency. RESULTS: All dogs were continent postoperatively. The results of the 10-minute pad test showed no significant difference in the weight increase of the pad among the control, sham-operated and mucosa-replaced dogs. Urethral stricture developed in 1 mucosa-replaced dog. Histological examination revealed that all of the grafted oral mucosa survived in the urethra. CONCLUSION: These results indicate that the urethral mucosa can be replaced by oral mucosa without damaging the continence mechanism in female dogs.

Animals↗
PubMed1995

Three diterpene dilactone glycosides from Podocarpus nagi.

Three water-soluble constituents, nagilactosides C-E, were isolated from Podocarpus nagi. Their structures were determined by chemical and spectroscopic methods, respectively. Nagilactoside C was identified as 1-deoxy-nagilactone A-2 alpha-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranoside, nagilactoside D as 1-deoxy-nagilactone A-2 alpha-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside, and nagilactoside E as nagilactone A-1 beta-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyransoide.

Carbohydrate Conformation↗
PubMed1994

[Relationship between syndrome differentiation and blood total fibrinolytic activity, superoxide dismutase and albumin in nephrosis syndrome].

Relationship between the Syndrome Differentiation and total fibrinolytic activity (TFA), superoxide dismutase (SOD), serum albumin (Alb) was observed in 118 pediatric patients with nephrosis syndrome. The results suggested that there was significant difference between Damp-Heat type and Spleen Deficiency type in terms of blood TFA, SOD and serum Alb. Very significant positive correlation was found between serum Alb and TFA, P < 0.01. The level of TFA in pediatric patients with edema was significantly lower than that in normal children, the more the degree of edema, the more the level of TFA activity. It was shown that there would be possibility to find intrinsic connection between Syndrome Differentiation and laboratory findings.

Adolescent↗
PubMed1993

Urethral carcinosarcoma following total cystectomy for bladder carcinoma.

A patient with carcinosarcoma of the urethra occurring 15 years after a radical cystoprostatectomy for transitional cell carcinoma is presented. The tumor arose from the penile urethra and invaded the glans penis and penile corpus cavernosum. The tumor was composed of mixed carcinoma (squamous cell carcinoma, adenocarcinoma and transitional cell carcinoma) and rhabdomyosarcoma. Biopsy of the right inguinal lymph node showed simultaneous metastasis of sarcomatous and transitional cell carcinoma elements.

Adenocarcinoma↗
PubMed1993

Molecular mechanism of high energy proton radiation--Raman spectroscopic character of microcosmic damage in the space structure of DNA.

High energy proton is an important type of the space radiation. The paper investigates the radiation effect of high energy proton (27.9 MeV) on DNA aqueous solution in the field of the molecular mechanism. The following information about the microcosmic damage to the space structure of DNA was obtained: (i) breakage of a part of interbase hydrogen bonds which maintained double helical structure of DNA; (ii) damage on four bases, in which the damage on adenine ring was the most serious; (iii) obvious change of deoxyribose; (iv) serious damage on backbone phosphate ion (PO2-) and phosphate diester (PO2) and the occurrence of scissions of double-stranded and single-stranded DNAs; (v) obvious decrease in the amount of B-form conformation.

Animals↗