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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 379 records · Page 21Linked to original sources
PubMed1998

[Clinical observation of splenectomy on chronic idiopathic thrombocytopenic purpura in 63 patients].

OBJECTIVES: To investigate the effectiveness of splenectomy in patients with idiopathic thrombocytopenic purpura who failed to respond to conservative management. METHOD: Sixty-three patients were treated with splenectomy and followed up for 2 months to 16 years (average 4.7 years). RESULT: The patients had symptoms of bleeding and their platelet count on average was 24 x 10(9)/L. The first, 3rd, 5th and 7th day after operation, the average platelet count was 110 x 10(9)/L, 202 x 10(9)/L, 251 x 10(9)/L and 246 x 10(9)/L. Their platelet recovered to normal during a week in 51 cases (80.9%). The total effective rate was 86.9% after follow-up for 2 months. The recurrence rate was 17.9% in 39 cases after follow-up for longtime. CONCLUSIONS: The curative effect of splenectomy is better in children than in adults. In patients with increased platelet have a favourable prognosis. Splenectomy is safe and effective in the treatment of idiopathic thrombocytopenic purpura.

Adolescent↗
PubMed1998

[Treating portal hypertension by subtotal splenectomy with retroperitoneal splenic transposition and devascularization: clinical study].

OBJECTIVE: To devise a new surgical procedure for improving the operative effect of portal hypertension caused by hepatic cirrhosis. METHOD: In treatment group, subtotal splenectomy with retroperitoneal transposition was performed in 36 patients of cirrhotic hypertensives. In control group, 36 patients were treated by devascularization. The follow-up period ranged from 3 months to 5.5 years (average 26 months). RESULT: In the treatment group, the rates of disappearance, improvement and absence of changes of esophageal varices were 11.5%, 61.5% and 26.9%, respectively, and in the control group those of improvement were 50.0%, absence of change 45.8% and aggravation 4.2%. There was a significant difference between them (P < 0.05). In the treatment group, hypersplenism disappeared in all. There was also significant difference between the two groups in immunological indexes (P < 0.05). DSA showed abundant collateral circulation in the residual spleen and retroperitoneal wall, which enabled the portal blood flow diverting to retroperitoneal tissues. CONCLUSION: This method possesses the advantages of devascularization and decompression shunt. It is of value in retaining part of spleen in surgical treatment of portal hypertension.

Female↗
PubMed1998

[The experimental research of free calcium of the lens epithelial cells in galactose cataract].

OBJECTIVE: To study the changes of free calcium in the lens epithelial cells (LECs) of galactose cataract. METHODS: Wistar rats, 28 days old, were fed with 50% galactose forage to form cataract models. Then the concentration of free calcium of LECs was measured at the 1st, 3rd, 7th, 10th, 14th, 19th days after the galactose diet was given. RESULT: The concentrations of free calcium in LECs of galactose cataract increased apparently and reached the maximum at the 10th day after galactose diet. The maximum was 4 - 5 times higher than that of the normal group. CONCLUSION: The calcium concentration of LECs in galactose cataract increases but the degrees at different phases are not the same. The maximal concentration is at the phase when the cortex is opacified.

Animals↗
PubMed1998

[Effect of dihydroquinghaosu on the development of Plasmodium yoelii yoelii in Anopheles stephensi].

AIM: To observe the effect of dihydro qinghaosu (DQHS) on the development of Plasmodium yoelii yoelii in Anopheles stephensi and to explore the possibility of whether DQHS has preventive effect against malaria. METHODS: Plasmodium yoelii yoelii-infected mice that had been administered with a single dose of different dosages (60 mg/kg, 120 mg/kg, 180 mg/kg and 240 mg/kg) of DQHS were exposed to mosquitoes to suck blood. The development of malaria parasites in the mosquitoes of the control group and the treated group were observed by light microscopy (LM) and transmission electron microscopy (TEM). RESULTS: DQHS exhibited certain inhibitory effect on the infectivity of gametocyte. The degree of inhibition was related to the developmental stages of gametocyte and the drug dosage. Immature gametocytes were more sensitive to DQHS than the mature gametocytes. With the increases in dosage, the positive rate and the density of oocyst and sporozoite decreased. However, the difference in the density of sporozoite between 180 mg/kg and 240 mg/kg treated groups was insignificant. TEM result showed damage of the membrane system and vacuolation in the cytoplasm of the oocysts (12-13 d) on mosquito midgut of 60 mg/kg 16 h treated group. The oocysts in the mosquitoes continued to develop after treated with 120 mg/kg of DQHS for 16 h on 3-day-instar. There was no significant difference (P > 0.05) in the density of oocyst and sporozoite between the control group and the treated group. CONCLUSION: DQHS can affect the infectivity of gametocyte and decrease the malaria transmission but cannot inhibit the sorogonic stage directly.

Animals↗
PubMed1998

[Design and study of carbon fiber tracheal prosthesis].

32 healty adult dogs were selected for this experiment. 10 of them were subjected to the tracheal biomechanics test using indices including the relation between stretcher ratio (lambda) and stress (T), the squeeze stress (delta jy) of medical silk thread on trachea, the side stress (Ts) inducing the tracheal collapse, the functional maximum angle (psi max) of tracheal, and the sever area torsion angle (theta max) of tracheal functional maximum curved. According to the indices measured, two types of tracheal prosthesis were designed, and were made of carbon fiber and silicon. They were the straight tube type tracheal prosthesis and the bifurcate type tracheal prosthesis. The straight tube type tracheal prosthesis was studied with a design of two groups comprising a total of 11 dogs. In the experiment group (n = 6), the outer surface of the tube was not coated with silicon, the average survival period was 379.8 days. In the control group (n = 5), the outer surface of the tube was coated with silicon, the average survival period was 90.4 days. The bifurcate type tracheal prosthesis was studied in 11 dogs, the average survival period was 4.32 days. The main causes of death in the experiment were infection and anastomotic dehiscent.

Animals↗
PubMed1998

[Seeds collecting of Ephedra sinica and treatment before sown].

Seeds collecting of Ephedra sinica and treatment before sown were studied. These results indicated that time collecting seeds and treating such as threshing, washing, drying, storing at low temperature and immersing seeds with chemical were available measures. Which could supply a reference for the culture of E. sinica.

Desiccation↗
PubMed1998

[Assessment accuracy of electronic root canal length measurement]

OBJECTIVE: To see the accuracy of "ROOT ZX" electronic root canal measurement in clinical endodontic practice. METHODS: Root canal length of 176 anterior teeth were measured by "ROOT ZX",after radiographs were taken,the distance between reamer tip and toot apex was measured,and then compared it with the distance between apical foramen and root apex of extracted teeth. RESULTS: Statistical analysis indicated no significant difference between two groups. CONCLUSION: It shows: that the electronic device can measure the root canal length accurately.It is believed that it has a higher value in clinical endodontic practice.

Journal Article↗
PubMed1998

Roles of sphingosine-1-phosphate in cell growth, differentiation, and death.

Recent evidence suggests that branching pathways of sphingolipid metabolism may mediate either apoptotic or mitogenic responses depending on the cell type and the nature of the stimulus. While ceramide has been shown to be an important regulatory component of apoptosis induced by tumor necrosis factor alpha and the Fas ligand, sphingosine-1-phosphate (SPP), a further metabolite of ceramide, has been implicated as a second messenger in cellular proliferation and survival induced by platelet-derived growth factor, neuronal growth factor, and serum. SPP protects cells from apoptosis resulting from elevations of ceramide. Inflammatory cytokines stimulate sphingomyelinase, but not ceramidase, leading to accumulation of ceramide, whereas growth signals also stimulate ceramidase and sphingosine kinase leading to increased SPP levels. We propose that the dynamic balance between levels of sphingolipid metabolites, ceramide, and SPP and consequent regulation of different members of the mitogen-activated protein kinases (JNK versus ERK) family is an important factor that determines whether a cell survives or dies.

Animals↗
PubMed1998

alpha 5 Subunit alters desensitization, pharmacology, Ca++ permeability and Ca++ modulation of human neuronal alpha 3 nicotinic receptors.

Functional effects of human alpha 5 nicotinic ACh receptor (AChR) subunits coassembled with alpha 3 and beta 2 or with alpha 3 and beta 4 subunits, were investigated in Xenopus oocytes. The presence of alpha 5 subunits altered some properties of both alpha 3 AChRs and differentially altered other properties of alpha 3 beta 2 AChRs vs. alpha 3 beta 4 AChRs. alpha 5 subunits increased desensitization and Ca++ permeability of all alpha 3 AChRs. The Ca++ permeabilities of both alpha 3 beta 2 alpha 5 and alpha 3 beta 4 alpha 5 AChRs were comparable to that of alpha 7 AChRs. As we have shown previously, alpha 5 subunits increased the ACh sensitivity of alpha 3 beta 2 AChRs 50-fold but had little effect on alpha 3 beta 4 AChRs. alpha 5 caused only subtle changes in the activation potencies of alpha 3 AChRs for nicotine, cytisine and 1,1-dimethyl-4-plenylpiperazinium (DMPP). However, alpha 5 increased the efficacies of nicotine and DMPP on alpha 3 beta 2 AChRs but decreased them on alpha 3 beta 4 AChRs. Immunoisolation of cloned human AChRs expressed in oocytes showed that alpha 5 efficiently coassembled with alpha 3 plus beta 2 and/or beta 4 subunits. As expected, human AChRs immunoisolated from SH-SY5Y neuroblastoma cells showed that AChRs containing alpha 3 and probably alpha 5 subunits were present, but alpha 4 AChRs were not. In brain, by contrast, alpha 4 beta 2 AChRs were shown to predominate over alpha 3 AChRs. Some of the brain alpha 4 beta 2 AChRs were found to contain alpha 5 subunits.

Animals↗
PubMed1998

Classification of breast cancer cells on the basis of a functional assay for estrogen receptor.

BACKGROUND: The receptor (ER) for estrogen (E2) is routinely assayed as a marker to determine the feasibility of anti-hormone therapy against breast cancer because ER-positive (ER+) tumors are much more likely to respond to anti-hormone therapy than are ER-negative (ER-). However 40% of ER+ breast cancer patients do not respond to anti-hormone therapy. We suggest that this unpredictability of therapeutic responses lies in the current ER assays, which measure only an initial component of the E2-responsive pathway, and that the difference depends upon altered downstream processes. We propose a functional criterion that subclassifies breast cancers on the basis of specific binding of ER to its cognate DNA sequence, the estrogen response element (ERE). MATERIALS AND METHODS: ER was identified in breast cancer cell lines by immunofluorescence assay, Western blot analysis, identification of ER-specific mRNA, and by interaction of the ER-ERE complex with three different ER-specific antibodies. ER-ERE complex formation was measured by electrophoretic mobility shift assay (EMSA). Transactivation of the E2-responsive gene was studied by transfection of cells with fusion gene construct with the promoter-containing ERE sequence and assay of reporter gene activity in the cell extracts. RESULTS: The growth of ER+ T47D cells was sensitive to tamoxifen, ICI-182,780, and ethynyl estradiol (EE2), whereas another ER+ breast cancer cell line, 21 PT, was resistant to these compounds. The estrogen receptor (ER) in the nuclear extracts of MCF-7 and T47D demonstrated hormone-dependent interaction with the response element (ERE) and also downstream transactivation of the E2-responsive PS2 promoter. But in the 21 PT cell line that was designated as ER- on the basis of ligand-binding assay and was found to be ER+ by all the other ER assays, ER-ERE interaction and PS2 promoter transactivation were independent of hormone. CONCLUSIONS: On the basis of the downstream functional assay of ER interaction with ERE, ER+ breast tumor cells can be subclassified into two categories. The first is E2-dependent (ERd+) and these cells should respond to anti-hormone therapy. The second type of ER interacts with ERE independent of E2 (ERi+) and constitutively transactivates responsive genes. It is predicted that the latter type of breast cancers will not respond to antihormone therapy.

Antibodies, Monoclonal↗
PubMed1997

Determination of ammonia in ethylene using ion mobility spectrometry.

A simple procedure to analyze ammonia in ethylene by ion mobility spectrometry is described. The spectrometer is operated with a silane polymer membrane., 63Ni ion source, H+ (H2O)n reactant ion, and nitrogen drift and source gas. Ethylene containing parts per billion (ppb) (v/v) concentrations of ammonia is pulled across the membrane and diffuses into the spectrometer. Preconcentration or preseparation is unnecessary, because the ethylene in the spectrometer has no noticeable effect on the analytical results. Ethylene does not polymerize in the radioactive source. Ethylene's flammability is negated by the nitrogen inside the spectrometer. Response to ammonia concentrations between 200 ppb and 1.5 ppm is near linear, and a detection limit of 25 ppb is calculated.

Air↗
PubMed1997

Fibroblast growth factor receptor 2 limits and receptor 1 accelerates tumorigenicity of prostate epithelial cells.

Progressive loss of the differentiated phenotype and communication with stroma accompanies the transition of nonmalignant rat prostate epithelial cells to anaplastic, malignant tumors. Here we show that cell surface expression of the fibroblast growth factor receptor 2 (FGFR2) tyrosine kinase is reduced in malignant tumor cell populations (type II) and undetectable at the mRNA level in 30% of cells. This is in addition to the irreversible loss by splice switching of the FGFR2 ectodomain that abrogates response to FGF-7 and homologues from the stroma. One hundred % of type II malignant cells express FGFR1, which is normally expressed in the stroma. Expression of the FGFR1 kinase in premalignant type I tumor epithelial cells by transfection accelerated progression to the malignant phenotype. In contrast to the FGFR2 kinase fused to the ectodomain of FGFR1, the FGFR1 kinase failed initially to support a mitogenic response to FGF-2 in type I tumor cells. However, the FGFR1-transfected cells acquired a mitogenic response after extensive proliferation of the cell population. Resident FGFR2 and ectopic FGFR1 appeared to be partitioned in the type I cells, because neither full-length nor truncated isoforms of FGFR1 affected the mitogenic response of the other. Restoration of the FGFR2IIIb kinase to malignant cells expressing FGFR1 depressed tumor growth rates, restored responsiveness to stromal cells, and restored epithelial cell differentiation. These observations reveal that homologous FGFR1 and FGFR2 kinases play very different roles in cell growth and differentiation and in development and support of the malignant phenotype.

Animals↗
PubMed1997

Neuronal cell nuclear factor--a nuclear receptor possibly involved in the control of neurogenesis and neuronal differentiation.

We have cloned from a cDNA library of neuronal derivatives of retinoic-acid-induced embryonic carcinoma cells a nuclear receptor that may be involved in the control of late neurogenesis and early neuronal differentiation. The receptor which is practically identical in sequence with germ cell nuclear factor, has been designated neuronal cell nuclear factor (NCNF). NCNF is exclusively expressed in the neuronal derivatives of PCC7-Mz1 cells, with the expression beginning within hours of exposure to retinoic acid. In the developing mouse brain, NCNF is expressed in the marginal zones of the neuroepithelium which are known to contain young postmitotic neurons. NCNF binds to the DR0 sequence thereby silencing transcription. Because NCNF does not recognize hormone response elements of other nuclear receptors tested and does not heterodimerize with these, it probably binds exclusively as a homodimer. NCNF may induce neuronal differentiation by repressing the activity of genes that permit cell fates other than the neuronal one.

Animals↗
PubMed1997

Effect of islet amyloid polypeptide on somatostatin inhibition of insulin secretion from isolated rat pancreatic islets.

In this study, we investigated the presence of islet amyloid polypeptide (IAPP) in somatostatin cells of rat endocrine pancreas and the effect of exogenous IAPP and somatostatin, separate or combined, on in vitro insulin secretion. By immunocytochemistry, IAPP was found in both B and D cells of rat pancreatic islets. Furthermore, the labeling density of IAPP in D cells was nearly four times higher than in B cells. After a 2-day preincubation in RPMI 1640 (11.1 mM glucose), isolated rat pancreatic islets were exposed to IAPP and/or somatostatin for 90 min in modified Krebs-Ringer bicarbonate (KRB) buffers containing 11.1 or 22.2 mM glucose, or 11.1 mM glucose + 10 mM L-arginine, respectively. At 11.1 mM glucose, insulin secretion was not affected by IAPP and/or somatostatin at concentrations investigated. Insulin response to 22.2 mM glucose was inhibited by exogenous somatostatin. Arginine-stimulated insulin secretion was also inhibited by somatostatin, and the effect was significantly potentiated with additional 10(-5) M IAPP. The study shows that rat pancreatic D cells have higher IAPP density than B cells in the same islets and that IAPP and somatostatin may cooperate on rat pancreatic B cells to regulate the insulin secretion in response to potent stimulation.

Amyloid↗
PubMed1997

The spinal muscular atrophy disease gene product, SMN, and its associated protein SIP1 are in a complex with spliceosomal snRNP proteins.

Spinal muscular atrophy (SMA), one of the most common fatal autosomal recessive diseases, is characterized by degeneration of motor neurons and muscular atrophy. The SMA disease gene, termed Survival of Motor Neurons (SMN), is deleted or mutated in over 98% of SMA patients. The function of the SMN protein is unknown. We found that SMN is tightly associated with a novel protein, SIP1, and together they form a specific complex with several spliceosomal snRNP proteins. SMN interacts directly with several of the snRNP Sm core proteins, including B, D1-3, and E. Interestingly, SIP1 has significant sequence similarity with Brr1, a yeast protein critical for snRNP biogenesis. These findings suggest a role for SMN and SIP1 in spliceosomal snRNP biogenesis and function and provide a likely molecular mechanism for the cause of SMA.

3T3 Cells↗
PubMed1997

A homeo-interaction sequence in the ectodomain of the fibroblast growth factor receptor.

Interaction of fibroblast growth factor receptors (FGFR) sufficient for a trans-phosphorylation event in which one intracellular domain is substrate for the other is essential for signal transduction. By analysis of the direct interaction of recombinant constructions co-expressed in baculoviral-infected insect cells, we identified a 17-amino acid sequence that is required for the stable interaction between ectodomains of FGFR. The sequence 160ERSPHRPILQAGLPANK176 (Glu160-Lys176) connects immunoglobulin modules II and III. In insect cells, the interaction between Glu160-Lys176 domains occurs independently of intact heparin or FGF binding domains. The sequence is not required for the binding of heparin or FGF-1, but is essential for mitogenic activity of the FGFR kinase in mammalian cells. The results support a model in which the homeo-interaction between Glu160-Lys176 in the ectodomain contributes to the interaction between intracellular domains in mammalian cell membranes (Kan, M., Wang, F., Kan, M., To, B., Gabriel, J. L., and McKeehan, W. L. (1996) J. Biol. Chem. 271, 26143-26148). We propose that the Glu160-Lys176 domain plays a pivotal role in restriction of the interaction between kinases by pericellular matrix heparan sulfate proteoglycan and divalent cations. Restrictions are overcome by FGF or constitutively by diverse gain of function mutations which cause skeletal and craniofacial abnormalities.

Amino Acid Sequence↗