Biomedical subjects

X Wu

Publications and source records attributed to X Wu.

At least 631 records · Page 35Linked to original sources

PubMed1998

Effects of acute moderate hypoxia on human performance of arithmetic.

To observe the effects of acute moderate hypoxia on human performance of arithmetic, the continuous calculation test, addition-subtraction test and mental arithmetic tests were made in 16 health young male subjects during exposure to altitude of 300 m (control), 3600 m, 4400 m and 5000 m by mean of hypobaric cabin simulation. Error rate of the continuous calculation test and reaction time of addition-subtraction test increased significantly and performance decreased significantly (P < 0.05) after exposure to 3600 m for 1 h. Reaction time, total number and performance of all tests decreased significantly (P < 0.05) during exposure to 4400 m. Performance of all tests decreased (P < 0.01) after exposure to 5000 m for 30 min.

Adolescent↗

PubMed1998

[Effect of repeated cerebral ischemia induced by lower body negative pressure on neuronal morphology and ions contents, ATPase activity of brain tissue in rats].

To investigate the effect of repeated + Gz-induced loss of consciousness on the brain and its mechanism, we observed the changes of ions contents, ATPase activity of brain tissues and neuronal morphology after repeated cerebral ischemia induced by lower body negative pressure(LBNP) in rats. Thirty male Sprague-Dawley rats were divided into 3 groups randomly. Rats were anesthetized and exposed to LBNP of -4 kPa at a rate of 0.67 kPa/s. The pressure rapidly returned to control level 2 min after EEG becomes isoelectric. Cortical Na(+)-K(+)-ATPase activity decreased significantly lh after one LBNP exposure (P < 0.05), While Na+, K+ and water contents of brain tissues showed a tendency to increase (P > 0.05). Na(+)-K(+)-ATPase activity decreased significantly while Na+, K+ and water contents increased significantly 1 h after three LBNP exposures, and ischemic changes were found in a few neurons. It suggested that three cerebral ischemia exposure induced by LBNP can result in disturbance of ion homeostasis and neuronal damage.

Animals↗

PubMed1998

[Influence of transjugular intrahepatic portosystemic stent shunts on portal and systemic hemodynamics of patients with portal hypertension].

OBJECTIVE: To determine the influence of transjugular intrahepatic portosystemic stent shunts (TIPSS) on portal and systemic hemodynamics of patients with portal hypertension. METHODS: Fifteen patients who had undergone TIPSS with 10 mm stents were studied. The parameters of portal, systemic and pulmonary hemodynamics were measured with Doppler sonography, direct portal pressure measurement, blood-gas analysis and Swan-Ganz catheter before and 30 min and 2 weeks after TIPSS. RESULT: Portal pressure decreased by 34% and 55.4%, and PO(2), SatO(2) increased by 67.7%, 21.3% and 68%, 20.4% respectively 30 min and 2 weeks after TIPSS. Portal blood velocity increased by 1.4 times 2 weeks after TIPSS. CO, CI, SI increased (P < 0.01) and SVR, PVR decreased (P < 0.01) after TIPSS. Also, RAP, PAP increased (P < 0.05). Renal blood flow increased (P < 0.01) and renal function significantly improved. CONCLUSION: TIPSS can not only decrease portal pressure and improve renal function, but also worsen portal and systemic hemodynamics. Cardiac and liver function should be monitored before and after TIPSS.

Blood Circulation↗

PubMed1998

[Surgical treatment of the hypopharyngeal and cervical esophageal carcinoma].

OBJECTIVE: To review the experience of surgical treatment of hypopharyngeal and cervical esophageal carcinoma. METHOD: Seventy-six patients with squamous-cell carcinoma of the hypopharynx and cervical esophagus underwent surgery in our department from 1980 to June 1997. The site of the tumour was in hypopharynx in 31 patients and in cervical esophagus in 45. RESULT: The resectability rate of hypopharyngeal carcinoma (HPC) was 98.6% (30/31). The types of the esophageal reconstruction included pharyngo-esophageal anastomosis (3 patients) platysmamyocutaneous flaps reconstruction (PMFR) (12) free jejunal interposition (3) and gastric tube transposition following total pharyngolaryngo esophagectomy (12). The resectability rate of cervical esophageal carcinoma (CEC) was 91% (41/45). The esophageal construction applied gastric tube after esophagectomy without thoracotomy except one. The postoperative morbidity was 36.5% for gastric tube reconstruction (including one died of heart failure), 33.3% (1/3) for free jejunal interposition and zero for PMFR. The overall follow-up was from 2 to 108 months (median: 56.5 months) and the 1-, 3-, 5-year survival rates were 79.3%, 60% and 31.6% respectively for HPC and 68.3%, 9.5%, 0% respectively for CEC. CONCLUSION: Our data demonstrated that the resectability rate of the HPC and CEC was quite high but the long-term result of HPC was better than that of CEC. The PMFR after pharyngolaryngo-cervicalesophagectomy was a safe, effective operation with low morbidity and excellent long-term results.

Adult↗

PubMed1998

[Hard nucleus cataract extraction by phacoemulsification with intraocular lens implantation].

OBJECTIVE: To investigate the technique of phacoemulsification for hard nucleus cataract extraction and evaluate its therapeutic effects. METHODS: Three methods of phacoemulsification, the improved divide and conquer, the reserve lens cortex spin and no lens cortex spin, were performed on 62 eyes according to the type of nucleus hardness. RESULTS: With foldable or 5.5 mm PMMA intraocular lens implantation, the improved divide and conquer phacoemulsification was performed on 26 eyes, the reserve lens cortex spin phacoemulsification on 23 eyes and no cortex spin phacoemulsification on 13 eyes. At postoperative 3 days, 5 days and 30 days, the visual acuities without correction 0.5 or better were obtained respectively in 46 eyes (74.2%), 60 eyes (96.8%) and 61 eyes (98.4%). The major complications were corneal edema and posterior capsular rupture. CONCLUSION: The technique of phacoemulsification for hard nucleus cataract is worthy to be spread due to safety, easiness and minimum complication.

Aged↗

PubMed1998

[Intraocular pressure rise early after phacoemulsification with posterior chamber lens implantation].

OBJECTIVE: To investigate intraocular pressure (IOP) changes early after phacoemulsification with posterior chamber lens implantation. METHODS: The IOP was measured in 49 patients 53 eyes before and 10 - 12, 22 - 24, 46 - 48 hours after the operation. RESULTS: The IOP increased obviously in all eyes 10 - 12 hours after the operation, and rose more significantly from the baseline to the maximum 10 - 12 hours after surgery in 20 sutured eyes than that in 33 unsutured eyes (t = 4.41 and 3.32, P = 0.0001 and 0.0020, respectively). It was higher than 3 kPa in 16 eyes, 10 (10/20, 50.0%) in the sutured group, 6 (6/33, 18.2%) in the unsutured group, respectively, and the difference was significant between the two groups (chi2=5.9820, P=0.014). The IOP decreased markedly 22 - 24 hours, and returned to the baseline level 46 - 48 hours after the operation. CONCLUSION: These results indicate that IOP increases early after phacoemulsification with posterior chamber lens implantation, especially in sutured eyes. Therefore, to apply corresponding management properly in time and obtain better therapeutic effects of the operation, IOP should be measured regularly.

Adult↗

PubMed1998

[Determination of trace 4,4'-diaminobiphenyl, 4-nitrophenol and phenol in environmental water by high performance liquid chromatography].

A method for simultaneous determination of trace 4,4'-diaminobiphenyl, 4-nitrophenol and phenol in waste water by high performance liquid chromatography with spectrophotometric detection is reported. These components were separated on a Phenomenex Spherex C18 column with V(acetonitrile): V(ether): V(50 mmol.L-1 acetate) = 12:10:78 buffer (pH 6.0) as mobile phase and UV detection at 275 nm. The detection limits were 0.14, 0.19 and 0.08 ng for 4,4'-diaminobiphenyl, 4-nitrophenol and phenol, respectively, when the ratio of signal to noise was 2. The relative standard deviation was < 2.2 (n = 6). This method is sensitive and has been applied to the analysis of environmental water samples with satisfactory results.

Bibenzyls↗

PubMed1998

[The time-frequency analysis of the exercise ECG signal].

Exercise ECG indicates information about the heart load status in the exercise test. It is very significant to represent the characteristics of the exercise ECG for evaluating the exercise load test. This article introduces the principle of Winger-Ville Distribution time-frequency analysis and its implementation. By applying this method to analyse exercise ECG, some results were acquired. It is a promising method to do research of the exercise ECG in the time-frequency plane.

Algorithms↗

PubMed1998

[Exploration on statistical method for calculating intensity of the infection in residents in nationwide sampling survey of schistosomiasis].

AIM: To set up statistical methods for calculation of intensity of schistosome infection in residents in nationwide sampling survey of schistosomiasis. METHODS: Based on the epidemiological survey of schistosomiasis and according to the medical statistics for multiple stratifying and clustering random sampling, the calculation method on intensity of schistosome infection was inferred. RESULTS AND CONCLUSION: Nine formulas were worked out for the calculation of the intensity of schistosome infection in different endemic provinces with different ecotypes. These formulas are of practical value.

China↗

PubMed1998

[The study of multi-phrase multi-criterion steretactic radiotherapy treatment planning].

Steretactic radiotherapy treatment planning is an important part of X-knife radiosurgery. In this paper the theory of multi-phrase-multi-criterion steretactic radiotherapy treatment planning is proposed, which is composed of three phrases. In the first stage, linear programming is used to reduce the resolution space. A kind of quadriatic programming is used in the second phrase in order to get high and well-distributed dose distribution. In the third phrase, an improved method of constrained simulated annealing is used to get the effect of conforming with the clinical practice. In correspondence with three-phrases optimization, three criterions are used respectively. The experiment results show that the theory proposed is correct.

Humans↗

PubMed1998

[Antisense oligodeoxynucleotide targeted at the pre-s region of DHBV could inhibit virus replication in vivo].

To study the antiviral effect of antisense oligodeoxynucleotide (AS-ODN), AS-ODN phosphotioates targeted to DHBV Pre-S region (951-968nt) (5'-TATCTCCTCCATTGTTTG-3') was synthesized. Two day-old ducklings were infected i.p. with 150 microliters of DHBV (3 x 10(8) copies/ml DHBV). After 12 days, 6 DHBsAg and DHBV DNA positive ducks were divided into two groups. In treated group, each duck was injected i.v. AS-ODN 20 micrograms/gram weight/day for 10 dyas successively, while in the control group, each duck received the same volume of normal saline for 10 days. Sera from ducks prior to treatment and treated after 6, 10 days were collected, and after 10 days ducks were sacrificed and livers were examined. DHBsAg was significantly decreased in all three treated ducks after 10 days of AS-ODN treatment. One of these ducks showed decreased DHBsAg even 6 days after treatment. Two out of three treated ducks showed decreased serum DHBV DNA, while one remained unchanged. In contrast, none of the control group showed decreased DHBsAg and DHBV DNA did not change. By Southern blot, DHBV DNA in the liver significantly decreased in 2/3 of the treated ducks and decreased in the other duck. In all control ducks, DHBV DNA remained strongly positive. Data indicated that AS-ODN targeting at Pre-S region could partly inhibit the replication of DHBV.

Animals↗

PubMed1998

[A novel gene delivery system targeting to epidermal growth factor receptor overexpressing cancer cells].

A polypeptide with 33 amino acid residues was designed and synthesized. Its C terminal was composed of multiple lysine residues, which played as a DNA condensing agent, whereas the N terminal was the receptor binding domain of Epidermal Growth Factor(N32-K48). Through a spontaneous self-assembly process with electrostatic interaction, the synthetic peptide combined with a luciferase expression vector, pEBluc, to form an EGF receptor targeting nucleic acid complex. Significant luciferase activity was detected 48 hours after adding this complex directly to the culture medium of the A431 cells. This synthetic peptide could be used to construct a gene transfer system mediated by the endocytosis via EGF receptor. It promoted a very possibility of the gene therapy for the cancers such as glioma, melanoma and squamous carcinoma which are known of epidermal growth factor receptor overexpression.

Carcinoma↗

PubMed1998

[Correlation noise detection in encephaloblood-fluidity signal].

The aim of this study was to remove random white noise which mixes with encephaloblood fluidity signal. Based on the principles of correlation detection and a priori knowledge of encephaloblood fluidity, the authors adopted the coherent averaging method and obtained pure encephaloblood fluidity signal. The result of practical use has demonstrated that the more times the averaging progresses, the more distinctly the wave shows up.

Algorithms↗

PubMed1998

[Application of constrained simulated annealing to 3D stereotactic radiotherapy treatment planning].

In this paper, linear programming and constrained simulated annealing are combined to optimize X-knife stereotactic radiotherapy treatment planning. In the first phase, linear programming reduces the resolution space, which is favourable to the adoption of little granularity in the second phase. Our experiment demonstrates that after the two-phase optimization, we attain the expected result.

Algorithms↗

PubMed1998

[Studies on target localization of Parkinson's disease treated with gamma knife].

Ninety cases of Parkinson's disease were treated in our center from Dec. 1993 to Aug. 1997. Based on our work, we have developed a method for the MR localization in the treatment of Parkinson's disease with Gamma knife, including the fixing of stereotactic frame, the selection of target, and the correction of the target's coordinates. In this paper, the effects of fixing of coordinate frame on the localization of target have been analyzed. Also presented are the errors of the coordinates of the selected targets, compared with those corrected. The method reflects a new idea for target localization.

Algorithms↗

PubMed1998

[Effect of aqueous extract of Lepidium apetalum on dog's left ventricular function].

Left ventricular myocardial contractility, function of pump-blood and coronary flow in dog were increased by i.v. aqueous extract of Lepidium apetalum (AELA) 0.2 ml/kg (containing crude medicinal herb 2 g/ml). The effects were similar to i.v. isoperaline 10 micrograms/kg, but AELA did not obviously change heart rate, arterioveno-oxygen partial pressure difference and arteriovenooxygen solubility. The results indicated the AELA had advantages of cordial effect and increasing coronary flow instead of enhancing oxygen consumption of cardiac muscle.

Animals↗

PubMed1998

[A preliminary report of the effect of levodopa and carbidopa for childhood amblyopia].

PURPOSE: To explore the short-term effect of levodopa and carbidopa in 36 children (4.5-14 years) with refractory amblyopia. METHODS: 36 cases of incurable childhood amblyopia treated with occlussion with visual acuity stably for 6 months were retreated by levodopa and carbidopa 1.5 mg/kg, 0.38 mg/kg respectively for 3 months. Visual acuity, fusional and stereoscopic function, retinal light sensitivity and scotomas were observed at 1 and 3 months after tablet taken. Medicine side effects were observed. RESULTS: At 3 months, the visual acuity of 88.89% eyes were improved(average 2.27 +/- 1.26 line), fusional and stereoscopic function were restored in 10 and 6 cases respectively. Retinal light sensitivity significantly increased, scotomas disappeared in 19 eyes and contracted in 6 eyes. The basic cure rate was 42.86% Less side effect were found. CONCLUSION: Average dose levels(1.5/0.38 mg/kg) of levodopa and carbidopa were an effective and secuity method to improve visual function of refractory childhood amblyopia.

Adolescent↗

PubMed1998

[Effect of AHMED valve implantation surgery for the treatment of neovascular glaucoma].

PURPOSE: To evaluate the efficacy of the valve implantation for the treatment of neovascular glaucoma. METHODS: 15 cases (15 eyes) neovascular glaucoma were treated with AHMED valve implantation surgery, and followed up for 6 to 42 months. RESULTS: The IOP of the cases is lowered from 6.01 +/- 1.28 kPa (1 kPa = 7.5 mmHg) preoperatively to 1.96 +/- 0.68 kPa postoperatively. The success rate was 80.0% (The criteria of success is 0.80 kPa < or = IOP < or = 2.80 kPa and without severe complication that influence the visual acuity). The common postoperative complications included hyphema, shallow anterior chamber. CONCLUSION: The AHMED valve implantation surgery can lower the IOP, increase the operative success rate and preserve the visual function effectively. It is regarded to be an effective, safe method to treat neovascular glaucoma.

Adult↗