Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 379 records · Page 21Linked to original sources

PubMed1998

[The relationship of vascular endothelial growth factor and angiogenesis to the progression of gastric carcinoma].

OBJECTIVE: To investigate the relationship of vascular endothelial growth factor (VEGF) and angiogenesis to the progression of gastric carcinoma (GC). METHODS: VEGF protein expression and microvessel density (MVD) in 56 cases of human GC and VEGF mRNA expression in some cases were examined by use of immunohistochemical staining and in situ hybridization technique respectively. MVD and VEGF expression were analysed together with their relation to histologic types, depth of invasion, growth pattern, lymph node metastasis, distant metastasis and relapsing rate of GC. RESULTS: MVD was significantly higher in VEGF-positive GC than in VEGF-negative GC (P < 0.01). MVD and VEGF positively correlated with depth of invasion (P < 0.01), lymph node metastasis (P < 0.05) and distant metastasis (P < 0.05), but their relation to the histologic types and growth pattern of GC was not significant. The 5 year survival rate was significantly lower in GC patients with positive expression of VEGF or with MVD > or = 43. The expression of VEGF mRNA was consistent with that of VEGF protein, but the distribution is different. CONCLUSION: VEGF is highly related to angiogenesis of GC and promotes growth, invasion and metastasis of GC. VEGF expression or MVD is one of the predictors for the biological behavior of GC.

Adenocarcinoma↗

PubMed1998

[Lecture of principles and applications of capillary electrophoresis (VI) Applications of CE in DNA analysis, carbohydrate analysis and capillary ion analysis].

A review with 87 references on the application and new development of CE in DNA analysis, carbohydrate analysis and capillary ion analysis is presented. The DNA analysis included determinations of nucleotide, nucleoside and bases by CZE and MECC. It also includes dsDNA, PCR products analysis, purity control of oligonucleotide and DNA sequencing by CGE. Sometimes LIF detector needs to be introduced into DNA analysis. The carbohydrate analysis includes the methods for chemical derivatization and direct determination of carbohydrates by different CE modes. The capillary ion analysis includes the principle and determination of anions and cations.

Animals↗

PubMed1998

[Reconstruction of circumferential defect of cervical esophagus with platysma myocutaneous flaps after resection of hypopharyngeal carcinoma].

OBJECTIVE: To show the results of reconstruction of circumferential defect of cervical esophagus with platysma myocutaneous flaps after resection of hypopharyngeal carcinoma in 11 cases. METHODS: Total larynx, pharynx and cervical esophagus were resected and a permanent tracheostomy was made in the patients, because the cancer had invaded the larynx and cervical esophagus. Two platysma myocutaneous flaps were designed and dissected at both anteror-lateral neck, which was about 3.5-4 cm x 7-10 cm respectively. The flaps were made into a skin tube. The upper edge of the skin tube was sutured to the cut end of the pharynx and the lower sutured to the end of the esophagus. RESULTS: All of the flaps survived and there was no death after operation. There was fistula in 2 cases. The fistula healed after 14 days and 18 days respectively. All cases were normal in swallowing food. CONCLUSIONS: The operative methods, advantages and experiences are also descussed.

Aged↗

PubMed1998

[Coexisting pheochromocytoma and renal artery stenosis].

OBJECTIVE: To improve the diagnosis of coexisting pheochromocytoma and renal artery stenosis. METHOD: Four patients with coexisting pheochromocytoma and renal artery stenosis were treated. RESULT: After removal of the pheochromocytoma, the blood pressure became normal in two patients combined with resection of kidney with renal artery stenosis, and one patient with local adhesion loosened. The hypertension, however, persisted in another patient after the resection of pheochromocytoma even though the long segment of renal artery stenosis was relieved. CONCLUSION: After pheochromocytoma was diagnosed with its known position, coexisting renal artery stenosis should be suspected according to one of the following conditions: (1) Vascular murmurs are noted at the area of the upper abdomen or back; (2) One of the kidneys becomes less sized; (3) Using the inhibitor of receptor alpha only has no effect lowering blood pressure and it is necessary to add the inhibitor of angiotension; (4) Postoperative hypertension does not resolve when no remaining pheochromocytoma is present. the renal artery stenosis can be reversed after both removal of pheochromocytoma and loosening of adhesion in case of stenosis due to the pressure of the tumor and adhesion caused renal artery angling and local stricture. Extensive stenosis or closure, however, can not be corrected with severe atrophy of renal parenchyma due to pheochromocytoma, and the resection of kidney should be indicated.

Adolescent↗

PubMed1998

[Prognostic value of tumor vascularity in gastric carcinoma].

OBJECTIVE: To determine whether tumor angiogenesis correlates with progression of gastric carcinoma. METHOD: Microvessel counts (MVC) of 131 specimens resected from patients with gastric carcinoma were investigated by immunohistological staining with a monoclonal antibody against F-VIII RAg, counting the mean number of microvessels in the five areas of highest vascular density under 200 times magnification microscopy. Correlation among MVC, various clinicopathologic factors, and prognosis was studied. RESULT: MVC increased with TNM stage, the MVC of patients with advanced stage disease was significantly higher than that of early stage patients (P < 0.01). MVC was significantly higher in tumors with deep penetration (P < 0.05), lymph node metastasis (P < 0.001) and distant metastasis (P < 0.05) than in those without invasion and such metastasis. The recurrence rate after curative resection in hypervascular group (MVC > or 16) was 58.4%, which was significantly higher (P < 0.05) than that in the hypovascular group (MVC < 16). Moreover, the prognosis of patients with a high MVC was significantly poorer than that of those with a low MVC. The probability of 5 year survival rate was estimated by P = e(1.6231-0.1036 x MVC)/1 + e(1.6231-0.1036 x MVC). Multivariate analysis indicated that MVC is an independent prognostic factor in gastric cancer. CONCLUSION: Angiogenesis within gastric cancer is an indicator of tumor behavior and may identify patients at higher risk for recurrence and poorer prognosis.

Adult↗

PubMed1998

[Treatment of portal hypertension by using pericardial vascular disconnection and mesocaval side-to-side shunting].

OBJECTIVE: To prevent post-operative bleeding, to maintain the blood supply to the liver from the portal vein and to reduce the incidence of hepatic encephalopathy. METHOD: The blood vessel was cut around the cardial opening and the venae cavae was anastomosed in 37 patients with portal hypertension. RESULT: The success rate of surgery was 100%. The free portal pressure (FPP) was 3.16 +/- 0.581 kPa, which was lower than the FPP (3.91 +/- 0.642 kPa) before operation (P < 0.01). Follow-up for 5 to 22 months showed that liver function recovered from III to I in 5 patients, and from III to II in 7. Ascites disappeared in all and varix improved in 82.9% patients. CONCLUSION: Cutting flow combined with fraction flow can effectively maintain the blood supply to the liver in treating portal hypertension.

Adolescent↗

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

[Peripheral corneal edema after cataract extraction].

OBJECTIVE: To report a rare type of corneal edema, i.e. peripheral corneal edema after cataract extraction---Brown-Mclean syndrome. METHODS: Clinical charts of 8 affected eyes in 5 patients were reviewed. Ultrasound pachymetry was used to determine central corneal thickness. Cell densities were measured by specular microscopy. The clinical characteristics and pathogenesis were discussed. RESULTS: The average time from operation to initial diagnosis was 10.5 years. The typical edema started inferiorly and progressed circumferentially, but central portion of the cornea was clear. The corneal thickness at edematous area was increased. The cell counts of endothelium was decreased in our patients. Additionally, the edema was associated with a punctate orange-brown pigmentation on the endothelium. CONCLUSIONS: So far this new syndrome of corneal edema has not been reported in china. Its clinical characteristics are not similar to that of conventional edema after intracapsular cataract extraction. The pathogenesis of this curious condition is still unknown. It may be associated with an aphakic eye, chronic uveitis and hereditary factors.

Adult↗

PubMed1998

[Hemorrheologic analyses of anterior ischemic optic neuropathy].

OBJECTIVE: To find the pathogenic factor of non-temporal arteritis anterior ischemic optic neuropathy (AION). METHODS: Several items of hemorheology in 39 cases (19 males and 20 females) of acute non-temporal arteritis AION at papilloedema stage were examined and compared with that of the control group including normal comparable 20 males and 20 females. RESULTS: The results showed that hematocrit (HCT), fibrinogen, low shearing viscosity, aggregation index, erythrocyte electrophoresis time were higher in the AION group than that of the control group (P < 0.01 or P < 0.05). Besides, high shearing viscosity and plasma viscosity in the female patient group are also higher than that of the control group (P < 0.01). CONCLUSION: The high blood viscosity is closely related to the pathogenesis of non-temporal arteritis AION.

Blood Viscosity↗

PubMed1998

[Research and development of the surface EMG detection and analysis system].

To meet the requirement of developing myoelectric controller for a man-machine systems, a surface electromyography (EMG) detection and analysis system is discussed in this paper. This system consists of two parts--data acquisition hardware and signal processing software. In the surface EMG acquisition system both wire and wireless TELEMG are available. In the surface EMG processing system various methods are integrated such as the methods in time domain, the methods for frequency analysis, and also including some newly developed methods, e.g., wavelet transform and fractal analysis. This system provides a useful platform for research and development of the myoelectric controller that is widely used in rehabilitation engineering products.

Electromyography↗

PubMed1998

[Study on the surface EMG pattern classification with BP neural networks].

This paper presents a surface electromyography (EMG) motion pattern classifier which combines Neural Network (NN) with parametric model such as autoregressive (AR) model. This motion pattern classifier can successfully identify four types of movement of human hand, wrist flexion, wrist extension, forearm pronation and forearm supination, by using of the surface EMG detected from the flexor carpi radialis and the extensor carpi ulnaris. The result shows that it has a great potential application to the control of bionic man-machine systems such as prostheses because of its fast calculating speed, high recognition ability, and good robust.

Arm↗

PubMed1998

[Researches on the nucleotide sequencing of the recombinant Sj 22.6 kDa antigen gene of Schistosoma japonicum].

AIM: To sequence the cloned gene in pGSj24 and to identify the encoded protein. METHODS: The cloned gene in pGSj24 was digested from the recombinant plasmid by EcoRI, ligated into the M13mp19 vector and sequenced by automatic sequencer. The sequence was analyzed by Goldkey DNA and Protein Analytical Program and DNASIS Program. RESULTS: The pGSj24 cloned gene was demonstrated to be 840 bp containing one opened reading frame (ORF) with an initiation codon ATG at position 23 nt and a termination codon TAA at position 596 nt, encoding a protein with a molecular weight of 22.6 kDa. At the upstream and downstream of the ORF there were termination codons, so the encoded protein was unable to be larger. However, there was a termination codon TAA at position 11 nt, suggesting why the 22.6 kDa protein expressed separately. The nucleotide sequence of the pGSj24 cloned gene shared 95% identity with that of the corresponding part of S. japonicum 22.6 kDa antigen gene, and 99.7% identity in the encoding part. The deduced amino acid sequence analysis showed a sequence motif known as EF-Hand calcium binding domain, several endoplasmic reticulum targeting sequences and microbodies C-terminal targeting signals. The possible antigen determinants were predicted within the amino acid fragments of 29-32aa, 63-68aa and 87-101aa. CONCLUSIONS: The cloned gene in pGSj24 is the gene that encodes Sj22.6 kDa antigen.

Amino Acid Sequence↗

PubMed1998

[Screening and characterization of Schistosoma japonicum reinfection-related cDNA clones].

AIM: To obtain cDNA clones coding for S. japonicum (Sj) reinfection-related specific immunologic molecules for vaccination or diagnosis. METHODS: An adult S. japonicum cDNA library, of which the cloning efficiency is 3.13 x 10(6), with directional inserts in the vector lambda gt11, was screened with pooled serum from 43 reinfected human cases in a schistosomiasis-endemic area with high level of Sj specific-lgG4 antibodies. Primers located several bases away from the insert position on the lambda gt11 arm were used to amplify the insert fragments by standard PCR. SILVER SEQUENCE (PCR-silver) DNA sequencing system was then used to sequence selected positive clones with relatively large inserts and homology comparison with GenBank database was also carried out. RESULTS AND CONCLUSION: Eleven phage plaques were defined as positive out of the 8.6 x 10(4) phage plaques immunoscreened by human specific lgG4 antibody. GenBank database retrieval showed that 4 new Sj gene clones including Sj reinfection-related specific protein-encoding gene and Sj mitochondrial protein-coding gene have been obtained.

Adolescent↗

PubMed1998

[The study on detection of human parvovirus B19 DNA in spontaneous abortion tissues].

116 spontaneous abortion tissues were detected for human parvovirus B19 (HPV B19) DNA by nested polymerase chain reaction. Of the abortion tissues detected, 66 were paraffin embedded and 50 were fresh abortion tissues, At the same time, 25 abortion tissues from healthy artificial abortion women were collected as control. The results showed that 27.3% (34/116) of 116 spontaneous abortion tissues were positive for HPV B19 DNA, and only 4% (1/25) were positive in the control group, the discrepancy was significant chi 2 = 5.769(P < 0.05). It suggests that there is a relationship between spontaneous abortion and HPV B19 infection. HPV B19 infection may be an important factor in spontaneous abortion.

Abortion, Spontaneous↗

PubMed1998

[Studies on the chemical constituents of Quercus mongolica].

Seven compounds were isolated from Quercus mongolica Fisch., six (1-VI) of them were identified as fridelin (I), beta-amyrin (II), 1-octadecanol (III), beta-sitosterol (IV), daucosterol (V) and gallic acid (VI) by means of chemical, physical and spectrosopic evidiences.

Fatty Alcohols↗

PubMed1997

Partial signaling by cytokines: cytokine regulation of cell cycle and Fas-dependent, activation-induced death in CD4+ subsets.

Fas-dependent, activation-induced death (AID) of T cells has been implicated in the regulation of peripheral T cell populations. We have previously reported that IL-2 plays a unique role in regulating sensitivity to AID in primary CD4+ cells. In this report we have compared the capacity of IL-2, IL-4, and IL-7 to increase entry into cell cycle vs their capacity to increase sensitivity to AID. Our data indicate that IL-2 plays a unique role in the regulation of AID in both Th1 and Th2 subsets and that with a given AID stimulus, cell cycle progression is necessary, but not sufficient, for AID. Interestingly, induction of cell cycle entry and sensitivity to AID can be dissociated (partial signaling) not only with different cytokines, but even with point mutations in IL-2 itself. This provides the first evidence that cytokine variants or pharmacological agents that mimic their action will be useful in enhancing selective elements of pleiotropic cytokine actions.

Animals↗

PubMed1997

Dissociation of cytokine signals for proliferation and apoptosis.

Cytokines such as IL-2 or IL-3 prevent cell death through apoptosis, either by preventing apoptosis directly or by sensitizing cells to survival factors present in serum. We demonstrate herein that BAF-B03 cells transfected with the wild-type IL-2R beta-chain undergo apoptosis when stimulated with IL-2 or IL-3 in the absence of serum. IL-2 also induced apoptosis in normal IL-2-responsive human T cell blasts in the absence of serum, and furthermore, epidermal growth factor and fibroblast growth factor induced increased rates of apoptosis in fibroblasts in the absence of serum, suggesting that cytokine-induced apoptosis in the absence of serum survival factors might represent an important biologic phenomenon. In the presence or the absence of serum, IL-2 and IL-3 induced expression of both c-Myc and Bax. In contrast, optimal cytokine-induced expression of Bcl-2 requires serum. Constitutive expression of Bcl-2 prevented cytokine-induced apoptosis. Transferrin mimicked serum by inducing an increase in Bcl-2 expression levels and concurrently prevented apoptosis. These results suggest that the balance between cytokine- and serum-induced Bcl-2 expression and cytokine-induced Bax expression may determine whether a cell undergoes cytokine-induced apoptosis. In BAF/BO3 cells expressing a mutant IL-2Rbeta with a deletion of the acidic domain, IL-2 did not induce either Bax expression or apoptosis. This suggests that the acidic domain of the IL-2R beta-chain plays an essential role in regulating IL-2-mediated Bax expression and apoptosis. Cytokine-induced apoptosis and its counterbalance by survival factors present in serum may play an important role in the regulation of cellular homeostasis during pathophysiologic processes.

Animals↗

PubMed1997

GA-binding protein-dependent transcription initiator elements. Effect of helical spacing between polyomavirus enhancer a factor 3(PEA3)/Ets-binding sites on initiator activity.

Many eukaryotic RNA polymerase II promoters contain initiator elements which direct accurate transcription in a TATA-independent manner. The PEA3/Ets-binding site (PEA3/EBS) is a common enhancer element in eukaryotic genes and is also found near the transcriptional start sites of many TATA-less promoters. We demonstrate that two PEA3/EBSs driving expression of the luciferase reporter gene, function as a minimal transcriptional initiator element. Maximal levels of transcription was achieved when two PEA3/EBSs, in either orientation, were located on the same face of the DNA helix, and the sites could be separated by up to three helical turns. In vitro transcription start sites directed by PEA3/EBS elements were clustered on either side of the upstream PEA3/EBS and were abolished by immunodepletion of GA-binding protein (GABP) from FM3A cell nuclear extracts. In vivo, co-transfection of GABPalpha and GABPbeta expression vectors enhanced reporter gene expression driven from PEA3/EBS initiator elements. Like other initiator elements, the PEA3/EBS elements were activated synergistically by upstream Sp1-binding sites. Thus, our results establish GABP as both a transcriptional activator factor and as an initiator factor.

3T3 Cells↗