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Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 433 records · Page 24Linked to original sources
PubMed1998

[Study on mechanisms of T lymphocyte function changes in mice under simulated weightlessness in terms of IL-2 and Bcl-2 gene transcription].

To understand the mechanisms of T lymphocyte function changes under simulated weightlessness T lymphocyte proliferation (MTT assay), IL-2 production (biological assay), IL-2 gene (dot blot) and Bcl-2 oncogene (RT-PCR) transcription of splenic cell were observed in mice. The results showed that on the 7 th and 14 th day of simulated weightlessness T lymphocyte proliferation and IL-2 production decreased and significant on the 14 th day; on the 7 th and 14 th day of simulated weightlessness IL-2 and Bcl-2 gene transcription decreased, significant on the 14 day. It demonstrated that simulated weightlessness inhibits IL-2 production by decreasing IL-2 gene transcrition. IL-2 and Bcl-2 gene may be regulators of lymphocyte function under simulated weightlessness.

Animals↗
PubMed1998

[Effect of noise on human mental rotation performance].

To investigate the effect of moderate level low frequency noise on human mental rotation performance, letter rotation and compass orientation tests were performed in 24 healthy young male subjects during 2 h exposure to 85-95dB (A), it was found that during 120 min exposure to noise of 85dB (A), the mean reaction time increased (P<0.05), performance of reaction time and total performance decreased (P<0.01) significantly as compared with control in letter rotation test, meanwhile, performance of reaction time and total performance at 120 min exposure were significantly higher than that at 30 min (P<0.05). During 120 min exposure to noise of 95dB (A), the mean reaction time increased (P<0.01), the performance of reaction time and total performance decreased (P<0.01) significantly as compared with control in compass orientation test, meanwhile, performance of reaction time at 120 min were significantly higher than that at 30 min(P<0.05). The results show that exposures to 85 dB(A) and 95 dB(A) noise for 2 h have certain effect on the performance of human mental rotation and may affect performance of complex tasks with a higher workload.

Adolescent↗
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 dentin inorganic material during dentin bond].

OBJECTIVE: In order to investigated the effect of dentin inorganic material during dentin bond. METHODS: This study investigated the tensile bond strength (TBS) between 4-META/MMA-TBB resin and dentin treated with several dentin treating methods. RESULTS: When the dentin was treated with acid-salt pretreating solution system (APSS) consisting of 10% citric acid and 3% ferric chloride to remove smear layer, and then re-treated with NaOCl to resolve dentin collagen and reveal dentin inorganic material, TBS of the dentin was 5.93 MPa, and higher than that of control group (3.71 Mpa) (P < 0.05) whose dentin was treated with distilled water only. CONCLUSION: It was suggested that dentin inorganic material did play a proper role in dentin bond.

Acrylic Resins↗
PubMed1998

[Effect of the pH value of acid-salt pretreating solution system on dentin-bonding strength].

OBJECTIVE: In order to investigate the mechanism of dentin bond promoted by acid-salt pretreating solution system (APSS). METHODS: The tensile bonding strength (TBS) of 4-META/MMA-TBB resin to the dentin, which was treated by acid and retreated by APSS with different pH value, was tested. RESULTS: The TBS of dentin rose gradually from 10.41 MPa to 15.73 MPa with the decreasing of the pH value of APSS. The metallic salt solution containing acid or not, apparently affected the TBS of dentin. CONCLUSION: This study showed that the form of metallic ion in APSS correlated with the TBS of dentin.

Acrylic Resins↗
PubMed1998

[Surgical injuries influence on release of endothelin-1 and local blood perfusion of amputated extremities].

OBJECTIVE: To observe influence of amputations and surgical injuries on synthesis and release of endothelium-derived endothelin-1, and local blood perfusion of amputated extremities. METHOD: The plasma endothelin-1 concentrations of 18 patients preoperatively and postoperatively and the endothelin-1 concentrations of femoral artery wall in 80 SD rats were determined using radioimmunoassay technique before and after amputation. Local blood perfusion of amputated extremities in rats were determined using laser Doppler flowmetry. RESULT: The plasma endothelin-1 concentrations in the patients with surgical injuries increased obviously, reached peak value at fourth hour postoperatively, being approximately 3 times of that of the control group. The endothelin-1 concentrations of femoral artery wall in amputated rats also increased, reached peak value at second hour after amputation, being approximately 2 times of that of the control group, and then decreased gradually, at the same time the local blood perfusion decreased, reached its lowest value at second hour after amputation, being only 25 percent of the control value. The endothelin-1 concentration of rat femoral artery wall was negatively relative to local blood perfusion (r = -0.83). CONCLUSION: Injuries enhance synthesis and release of endothelin-1. It is probably one of the main causes of vasospasm after injuries.

Adolescent↗
PubMed1998

[Nontypical limited resection of the lung].

OBJECTIVE: To evaluate the role of limited resection in the treatment of lung disease. METHOD: From 1989 to 1996, 46 limited resections were performed on 35 patients with lung diseases. All patients were followed up for 0.5 to 7 years (mean 29.3 months). RESULT: There were no operative deaths and operative complications. In 16 patients with benign lung diseases, no recurrences and late complications were found. In 5 patients with primary lung cancers, 2 died 1.5 and 2 years after operation, respectively, and 3 are still living well for 2.5, 4 and 5 years postoperatively. In 14 patients with metastatic lung diseases (10 with bilateral multiple metastases), 216 metastatic lesions were excised. 1-, 3-, and 5-year survival rates were 78.5%, 50% and 21.4% respectively. CONCLUSION: Limited lung resection could be an additional option and a surgical alternative to conventional lung resection for some compromised patients.

Adolescent↗
PubMed1998

[An ultrasound biomicroscopic study on changes of the structure of ocular anterior segment after topical application of cycloplegia].

OBJECTIVE: To observe the changes of ocular anterior segment and the relation between the intraocular pressure (IOP) and these changes after the topical application of cycloplegia using ultrasound biomicroscope (UBM), especially to observe the changes of ciliary body thickness and ciliary body-lens distance. METHODS: The quantitative measurement of UBM and the measurement of IOP had been done in 48 normal eyes before and after the topical use of 2% homatropine solution. The results were statistically analyzed. RESULTS: In the parameter reflecting the change of the anterior chamber angle after using 2% homatropine, the trabecular iris angle decreased, the angle open distance 250 decreased, the iris thickness 1 increased, the anterior chamber became deeper and the iris-lens contact distance became shorter, and all these differences were statistically significant (P < 0.05). In the parameter reflecting the changes of ciliary body, the ciliary body thickness and the ciliary process thickness decreased, the scleral ciliary body angle increased, the iris-zonule distance decreased and the ciliary body-lens distance increased, and all these differences were significant statistically (P < 0.05). The IOP increased from 2.35 +/- 0.46 kPa to 2.43 +/- 0.47 kPa after the topical use of 2% homatropine, but the differences were not statistically significant (P > 0.05). CONCLUSIONS: After the topical application of cycloplegia, the anterior chamber becomes deeper, the anterior chamber angle becomes narrower, the ciliary body becomes thinner and moves backward and the ciliary body-lens distance increases. By using UBM the structure of ocular anterior segment in its moving state can be observed and these structures can be measured quantitatively. The ultrasound biomicroscopic imaging has its advantages in the morphological study of ocular anterior segment.

Adult↗
PubMed1998

[Studies of mechanism of malignant glaucoma using ultrasound biomicroscope].

OBJECTIVE: To study the mechanism of malignant glaucoma using ultrasound biomicroscope (UBM) combined with general A scan and to observe the conditions of cilio-lens block in living eyes at the realtime when malignant glaucoma is occurring. METHODS: 31 eyes from 27 patients with malignant glaucoma were evaluated and 54 normal eyes and 72 eyes of primary angle-closure glaucoma were studied as the controls. RESULTS: Of the 31 eyes, close attachments between the ciliary body and the lens were found in 18 eyes (58.1%) and slits between them were found in 13 eyes (41.9%) during the onset of malignant glaucoma. Ciliary body thickness increased significantly (P < 0.05). Fluid in the supraciliary space was found in 11 eyes. CONCLUSIONS: The mechanism of malignant glaucoma is associated with the abnormal relationship among anterior vitreous, ciliary process and lens periphery. Fluid in the supraciliary space makes the ciliary process closer to the lens periphery. It is one of the factors causing cilio-lens block. The ultrasound biomicroscopic image is a new better practicable method to diagnose malignant glaucoma during its onset compared with other methods at present used in the clinical work. It is much more valuable to differentiate the pupillary block glaucoma from malignant glaucoma by using ultrasound biomicroscopy.

Adult↗
PubMed1998

[Studies of mechanism of primary angle closure glaucoma using ultrasound biomicroscope].

OBJECTIVE: To investigate the mechanism of primary angle closure glaucoma (PACG) especially the role of the changes of ciliary body using ultrasound biomicroscope (UBM) combined with general A scan. METHOD: 99 eyes with PACG, including 50 eyes with acute and 49 eyes with chronic PACG, were evaluated and 58 normal eyes were in the control group. RESULTS: Compared with the normal eyes the PACG eyes had their anatomic features. They had a smaller corneal diameter, shorter axial length, shallower anterior chamber, thicker lens, more relative anterior location of lens, swelling of ciliary process and anterior rotation of ciliary body. All these differences were significant statistically (P < 0.05). Compared with the chronic PACG eyes the acute PACG eyes had a shallower anterior chamber and a more anteriorly situated lens position. The differences were significant statistically (P < 0.01). Compared with the normal eyes the acute PACG eyes had a shorter ciliary body - lens distance and the difference was significant (P < 0.05); the chronic PACG eyes also had a shorter ciliary body-lens distance, but the difference was not significant (P > 0.05). CONCLUSIONS: The PACG eyes have their anatomic features. Among these factors the pupillary block caused by the anterior displacement of lens and the narrow angle induced consequently are the common mechanism. The swelling ciliary process, the positional changes of the ciliary body and age-related thicker lens are possibly the initial causes causing the forward movement of lens, and the pupillary block plays a more important role in the pathogenesis of acute PACG.

Adult↗
PubMed1998

[Mandibular swing procedure for resection of pharyngeal and skull base tumors].

OBJECTIVE: To seek for a better approach for the resection of pharyngeal and skull base tumors. METHODS: The overall tumor distribution for the entire group was nasopharyngeal 2 cases, oropharyngeal 4, parapharyngeal space 5 and parapharyngeal infratemporal area 2 cases. All 13 cases of pharyngeal and skull base tumors had their tumors thoroughly resected via mandibular swing approaches. Five cases had retropharyngeal node dissections, 2 cases had unilateral modified radical neck dissections, 5 cases with defect oropharynx were reconstructed with the pectoralis major myocutaneous flap, 10 cases with malignant tumors had received adjutant radiotherapy after surgical procedures. RESULTS: Of the 13 cases, 10 were malignant, 3 were benign. The incision in 12 cases healed primarily, one case with malignant fibrocystic tumor got infective necrosis of pectoralis major myocutaneous flap, this case healed completely after more than two months. One case developed dysphagia postoperatively and was recovered by swallow training. One case had minimal occlusion disorder. All patients were followed up from 15 months to 3 years. Three cases with benign tumors achieved good clinical results and are living well. In the malignant group, one died of recurrence at 6 months postoperatively, one died of lung metastasis, 2 cases survived for 3 years, 2 for two years, 4 for one year. CONCLUSION: This procedure provides good exposure of the base of the skull, the pharynx and the parapharyngeal space as well as the clivus and upper cervical vertebrae; it allows dissection along the internal carotid artery and facilitates resection of the tumor en bloc. It provides operative safety and minimal morbidity.

Adolescent↗
PubMed1998

[The anti-ischemic effect of O, O-acetyldaurisoline].

O, O-acetyldaurisoline(Adau) is a derivative of daurisoline (Dau). In cultured PC12 cells, Adau was found to inhibit K+, Bay K8644 and norepinephrine induced intracellular free calcium concentration increase. Adau was also shown to protect PC12 cells from hypoxia-reoxygenation injury with EC50 of 64.3 +/- 12.5 mumol.L-1 by MTT assay. Adau (2.5, 5 and 10 mg.kg-1, i.v.) administrated 30 min before ischemia in bilateral carotid artery occlusion and four-vessel occlusion rats, attenuated the increase of lipid peroxide content and the decrease of SOD activity. These results show that Adau have significant protective effects against ischemic injury.

Alkaloids↗
PubMed1998

[Identification of a sulfhydryl-reducing agent-inducible protein highly homologous to protein synthesis elongation factor Tu in Bacillus subtilis].

It was examined that the effect of beta-mercaptoethanol and dithiothreitol treatments, which should affect disulfide bond formation of proteins, on cellular protein components of Bacillus subtilis. In LB medium, the treatments induced the synthesis of a 50 kD protein (P50), which is synthesized constitutively under normal growth condition and is a major cytoplasmic protein. P50 was also induced by heat shock, but not by sporulation. In Schaeffer's sporulation medium, however, P50 was not induced by the sulfhydryl-reducing agents. This suggests that the sulfhydryl-reducing agent-inducibility of P50 might depent on specific physiological condition(s). The amino terminal sequences of two of the four main V8 protease fragments of P50 were determined. A search in databases revealed that P50 was highly homologous to protein synthesis elongation factor Tu of B. subtilis.

Amino Acid Sequence↗
PubMed1998

[Subcloning and expression of coding region for cellulase binding domain of CBH I from P. janthinellum in E. coli].

The in vitro DNA manipulations, included the nested deletions, of cbh1 from P. janthinellum inserted into pUC18-181 were carried out. The two ends of fragments were modified into blunt ends and the fragments were self-ligated. Then, the encircled plasmids were transformed to E. coli JM109. Utilizing the characterization of CBD binding to crystalline cellulose, one catalytic domain deletion transformant producing active LacZ-CBD fusion protein was isolated from 24 transformants randomly picked from 400 transformants. The molecular weight of the LacZ-CBD fusion protein is 21 kD. The plasmid was designated pUC 18C. The LacZ-CBD fusion protein produced by JM109(pUC18C) was able to be purified by procedure of adsorption-desorption to cellulose. The pNPC activity of crude enzyme solution of JM109(pUC18C) induced by IPTG were zero, identified the JM109(pUC18C) has no CBHI activity.

Adsorption↗
PubMed1998

[Self-organization neural network based ultrasonic heart image segmentation].

Segmentation is one of the most difficult problems in multidimensional reconstruction of ultrasonic heart image. In the present paper, a segmentation method of ultrasonic heart image using the self-organization neural network has been studied. This is an unsupervised segmentation method, which can segment images through clustering automatically. The results show that the present method has significant benefits over the traditional K-means algorithm.

Algorithms↗
PubMed1998

Platelet endothelial cell adhesion molecule-1 expression modulates endothelial cell migration in vitro.

Endothelial cell migration is an important process that occurs during embryonic vasculogenesis and angiogenesis, wound healing, and tumor growth and metastasis, and after denudation injury following angioplasty and bypass grafting. Mechanisms regulating this process involve a complex interplay of cytoskeletal reorganization, cell-cell adhesion, and cell-extracellular matrix interactions. Platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is constitutively expressed in endothelial cells, leukocytes, monocytes, lymphocytes, and platelets. PECAM-1 undergoes dynamic dephosphorylation during endothelial cell migration in vitro and during vasculogenesis in the murine conceptus. In transfected 3T3 cells, in cultured endothelial cells, and in the murine conceptus undergoing vasculogenesis, the tyrosine phosphorylation state of PECAM-1 Y686 correlates with the migratory state of the cells. In the present study, we investigate the role of PECAM-1 in modulating endothelial cell migration in vitro using retroviral transduction of c-myc epitope-tagged, wild-type, Y686 to F-mutated PECAM-1 and extracellular domain-deleted PECAM-1 constructs in endothelial cells devoid of endogenous PECAM-1 (ECV304 cells) and in endothelial cells expressing high levels of endogenous PECAM-1 (bovine aortic endothelial cells, BAEC). In ECV304 cells, the expression of wild-type PECAM-1 inhibited migration rates, whereas in BAEC, overexpression of wild-type PECAM-1 had no effect. Expression of Y686 to F-mutated PECAM-1 or extracellular domain-deleted PECAM-1 in BAEC increased migration rates. These data support the concept that endothelial cell migration is modulated, in part, by a balance between PECAM-1 cytoplasmic domain-mediated "inside-out" and "outside-out" signaling resulting from PECAM-1-mediated cell-cell interactions and integrin-extracellular matrix interactions.

Animals↗