Biomedical subjects

S Tang

Publications and source records attributed to S Tang.

At least 73 records · Page 4Linked to original sources

PubMed2000

Novel action of pituitary adenylate cyclase-activating polypeptide. Stimulation of extracellular acidification in rat pituitary GH4C1 cells.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the vasoactive intestinal peptide/secretin family. Using microphysiometry, we have found that PACAP acutely (1 min) increased the extracellular acidification rate (ECAR) in GH4C1 cells approximately 40% above basal in a concentration-dependent manner. ECAR, maximally induced by PACAP, can be increased further by thyrotropin-releasing hormone (TRH), indicating that the signalling pathways for these two neuropeptides are not identical. In studies on the mechanism of PACAP-enhanced ECAR, we found that maximum stimulation of the cAMP/PKA pathway by treatment with FSK, or the PKC pathway with PMA, did not inhibit the ECAR response to PACAP. The PKC inhibitor calphostin C and the MAP kinase inhibitor PD98059 had no effect on the ECAR response to PACAP. Furthermore, PACAP induced little or no change in cytosolic Ca(2+) ([Ca(2+)](i)), while TRH induced a large increase in [Ca(2+)](i). However, the tyrosine kinase inhibitor genistein completely blocked PACAP-induced ECAR, suggesting involvement of tyrosine kinase(s). We conclude that PACAP causes an increase in ECAR in GH4C1 rat pituitary cells, which is not dependent on the PKA, PKC, MAP kinase or Ca(2+) signalling pathways, but does require tyrosine kinase activity.

Animals↗

PubMed2000

Comparison of the hypersensitive response induced by the tomato Cf-4 and Cf-9 genes in Nicotiana spp.

We have previously shown that tomato Cf-9 induces an Avr9-dependent hypersensitive response (HR) in Nicotiana tabacum and potato. We show here that Cf-4 also induces an Avr4-dependent HR in two tobacco species (N. tabacum and N. benthamiana). The HR induced by Cf-4 and Cf-9 was compared in stable tobacco transgenics by a seedling lethal assay and resistance to recombinant Potato virus X expressing Avr4 or Avr9. We also compared HR induction with Agrobacterium-mediated transient expression. The Cf-4/Avr4 combination induced a more rapid HR than Cf-9/Avr9. Sensitive assays for Cf-9 and Cf-4 function should prove useful for structure/function analyses of these resistance proteins in tobacco.

Agrobacterium tumefaciens↗

PubMed2000

Patient-held shared care records for individuals with mental illness. Randomised controlled evaluation.

BACKGROUND: Few formalized shared care schemes exist within psychiatry and the evidence base for sharing psychiatric care is weak. AIMS: To evaluate the utility of patient-held shared care records for individuals with long-term mental illness. METHOD: Cluster-randomised controlled parallel-group 12-month trial involving 90 patients with long-term mental illness drawn from 28 general practices. RESULTS: Carrying a shared care record had no significant effect on mental state or satisfaction with psychiatric services. Compared with controls, patients in the shared care group were no more likely to be admitted (relative risk 1.2, 95% CI 0.86-1.67) and attend clinic (relative risk 0.96, 95% CI 0.67-1.36) over the study period. Uptake of the shared care scheme was low by patients and professionals alike. Subjects with psychotic illness were significantly less likely to use their records (relative risk 0.51, 95% CI 0.27-0.99). CONCLUSIONS: Patient-held records may not be helpful for patients with long-term mental illness.

Adolescent↗

PubMed2000

The pH-dependent interaction of cinnamomin with lipid membranes investigated by fluorescence methods.

Cinnamomin, a new type II ribosome-inactivating protein (RIP), was found to be able to induce the release of calcein loaded in lecithin small unilamellar vesicles and the fusion or aggregation of the lecithin liposomes. Such induction could be promoted severalfold by a pH 5.0 environment, a condition similar to that in endocytic vesicles. Lowering the pH from 7.5 to 5.0 evoked conformational changes of cinnamomin and unmasked its hydrophobic areas, including the exposure of 1-anilino-8-naphthalenesulfonate (1,8-ANS) binding sites of the molecule. Some tryptophan residues with affinity to acrylamide were demonstrated to participate in the lipid-protein interaction. The pH dependent fusogenicity of type II RIP might suggest its in vivo function as a fusogen to exert its cytotoxicity.

Algal Proteins↗

PubMed2000

Non-specific depurination activity of saporin-S6, a ribosome-inactivating protein, under acidic conditions.

Among five ribosome-inactivating proteins tested only saporin-S6 could efficiently release the adenine from adenosine 20 of the synthetic oligoribonucleotide (SRD RNA) mimic of the sarcin/ricin domain of rat 28S rRNA with a Km of 9 microM and a kcat of approximately 0.4 min(-1) at pH 7.6. The optimal pH for the depurination activity of saporin-S6 is 5.0. However, saporin-S6 lost its site-specificity of depurination on SRD RNA around the optimal pH. The non-specific depurination activity of saporin-S6 was dependent on the enzyme concentration and pH conditions. These results are valuable to understand the diversity and the depurination mechanism of ribosome-inactivating proteins.

Adenine↗

PubMed2000

[Differentiation of embryonic stem cells into neuronal cells in vitro].

OBJECTIVE: To investigate the probabilities of embryonic stem (ES) cells differentiating into neuronal cells in vitro. METHODS: Mouse ES-D3 cells were cultured on the ES conditioned media without mLIF (mouse leukemic inhibitory factor, mLIF) for 4 days until ES cell aggregations was formed (embryonic bodies, EBs). The EBs were dissociated with trypsin and exposed to retinoic acid (RA) for another 4 days, and then replated onto adhesive substrate. Immunohistochemistry and RT-PCR assay were performed to identify the properties of the differentiated cells. RESULTS: The treated cells expressed neuronal proteins such as MAP-2 and GFAP. RT-PCR assay further identified that the induced cells expressed transcripts for neural associated genes including GABA-gamma subunit receptor, brain factor-1 and tyrosine hydroxylase (TH). CONCLUSION: ES cells can be successfully induced into neuronal cells expressing multiple properties of neurons in vitro, which could provide resourceful materials for neural transplantation.

Animals↗

PubMed2000

Health insurance and hospitalisation in urban China: bending to the wind of change.

The transformation from a planned economy to a market-oriented one in China has had profound impact on access to health care for a vast majority of the Chinese population. This article used the data from the national household health surveys conducted in 1993 and 1998 to show that the coverage of health insurance declined significantly from 54% to 39% among the urban population over the period, while rate of hospital admission came down from 45 inpatients per 1,000 people in 1992 to 30 inpatients per 1,000 people in 1997. It concludes that the declined coverage of health insurance and the rapid rise of medical care costs were the major factors affecting the access of the Chinese population to hospital care services.

China↗

PubMed2000

[Study on human sensitivity of extremely low frequency electromagnetic field].

In this paper, the action potential through membrane is calculated and analyzed based on the crowd model. The analysis shows that membrane action potential will be amplified if the coefficient k1, k2 meet some certain conditions. This effect could cause ionic current increase and even results in electroporation, membrane broken. The result can be used to explain some athermal bioeffect of living beings in weak EMF and is helpful for biomedicine application.

Cell Membrane↗

PubMed2000

[A study on the expressions and the correlation of TGF-beta and alpha-SMA in scars].

OBJECTIVE: To detect the expressions of TGF-beta(TGF-beta 1, TGF-beta 2, TGF-beta 3) and alpha-SMA and to investigate the probable effects of TGF-beta in the formation of hypertrophic scars as well as the expression of alpha-SMA in the scars. METHODS: 28 samples of hypertrophic scars, 19 samples of flat scars and 16 samples of normal skin have been examined immunohistochemically for the expressions of TGF-beta and alpha-SMA. Then a statistical and correlative analysis was carried out among the groups based on patient age, sex and scarring time. RESULTS: 1. TGF-beta and alpha-SMA have no expression in normal skin, but have varied expressions in hypertrophic scars and flat scars. 2. TGF-beta 1, TGF-beta 2 and alpha-SMA expressed highly in hypertrophic scar in comparison with normal skin and flat scar with a significantly statistical difference (P < 0.01). 3. There was a high expression of TGF-beta 3 in the flat scar and some hypertrophic scar that were from the female group or the scar over one year. 4. There was no statistical difference between the groups of teenage and adults. 5. The correlative analysis of TGF-beta to alpha-SMA demonstrated that the algebraic value of TGF-beta 1 + TGF-beta 2 - TGF-beta 3 correlates positively to alpha-SMA (r = 0.57). TGF-beta 3 correlates negatively to alpha-SMA(r = -0.80). CONCLUSIONS: 1. The formation and contraction of scar result from the synergic effects of TGF-beta 1, TGF-beta 2 and TGF-beta 3. TGF beta 1, TGF-beta 2 correlate the hyperplasia and contraction of scar, whereas TGF-beta 3 correlates the maturing of scar. To suppress the expression of TGF-beta 1, TGF-beta 2 or promote the expression of TGF-beta 3 would be beneficial to prevention of hyperplasia and contraction of scar. 2. It is reasonable to postulate that the female have stronger resistance to scar hyperplasia in that they have stronger expression of TGF-beta 3, which deserves further clinical observation and investigation. 3. The age has no influence on the expression of TGF-beta and alpha-SMA.

Actins↗

PubMed2000

Platelet-derived growth factor and basic fibroblast growth factor immunolocalized in proliferative retinal diseases.

OBJECTIVE: To study the role of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) in the development of proliferative vitreoretinopathy (PVR). METHODS: Immunohistochemical localization was performed on frozen sections of the epiretinal or subretinal membranes from 21 PVR patients using! monoclonal antibodies against PDGF and bFGF and the streptavidin peroxidase system. RESULTS: PDGF was expressed in 15 of 21 specimens (71.4%), and bFGF was expressed in 14 specimens (66.7%). Different cell density was seen in different types of epiretinal membranes. The cell density of vascular membranes induced by PDR and Eales disease was the highest (> or = 61 cells/field, x 1000); nonvascular membranes induced by PVR or traumatic PVR had moderate cell density (31-60 cells/field); and the macular membrane had the lowest cell density (< or = 30 cells/field). CONCLUSION: The presents of PDGF and bFGF in PVR tissues suggest that PDGF and bFGF may play an important role in the development of PVR.

Epiretinal Membrane↗

PubMed2000

[Minimal residual disease in bone marrow in patients with Ewing's sarcoma detected by RT-PCR amplification of EWS-FLI-1 fusion gene transcript].

OBJECTIVE: To set up a system for sensitively detecting minimal Ewing's sarcoma cells in bone marrow. METHODS: Ewing's sarcoma cell line T1 cells were serially diluted with normal bone marrow cells so that the concentration of tumor cells was 10(-3), 10(-4), 10(-5), 10(-6), 10(-7), and 0, respectively. Total RNA was isolated from these samples and cDNA was synthesized. EWS-FLI-1, a fusion gene formed due to chromosome translocation, was amplified with PCR. Bone marrow samples from five patients with Ewing's sarcoma patients with tumor metastasis were examined for EWS-FLI-1 transcript. RESULTS: T1 cells could be detected when one was present in 10(6) normal bone marrow cells. Thus the sensitivity of detection was 10(-6). A 434 bp EWS-FLI-1 transcript was detected in five Ewing's sarcoma patients examined at the time of diagnosis. After complete remission, EWS-FLI-1 was still positive on RT-PCR in 3 patients, although BM pathological examination was negative in all cases. CONCLUSION: RT-PCR for EWS-FLI-1 is sensitive enough to detect minimal residual Ewing's sarcoma cells in the bone marrow. It can identify residual tumor cells in pathologically negative bone marrow specimens.

Bone Marrow Cells↗

PubMed2000

[An experimental investigation between osseointegration and stability of implants used as orthodontic anchorage in dogs].

OBJECTIVE: To investigate the relation between osseointegration and stability of three kinds of implants used as orthodontic anchorage in dogs. METHODS: HA-coated, titanium coated, and uncoated titanium implants were inserted into each femur of two dogs. After heal period of three months, the orthodontic force of 200 g was applied by means of Ni-Ti springs, which were connected to the two adjacent implants, for two months. The position change of implants was measured and calculated. The shear bond strength of interface between implant and bone was measured with push-test. The interface was observed with scanning electronic microscope. RESULTS: The distance changes of HA-coated, T-coated and uncoated groups were (-0.50 +/- 1.78) mm, (-0.05 +/- 1.76) mm and (0.29 +/- 1.77) mm, respectively, which showed no statistical difference. The shear strength values were (2.88 +/- 0.55) MPa, (1.89 +/- 0.81) MPa and (2.14 +/- 0.49) MPa, respectively. HA-coated implant contacted with bone closely and the bond strength was the highest. The other two implants were found no significant difference in bond strength. CONCLUSION: The osseointegration was found at the interface among all three kinds of implants and bone and no displacement was found during application of clinical orthodontic force.

Animals↗

PubMed2000

[Clinical study on zhenjian granule in improving essential hypertension and insulin resistance].

OBJECTIVE: To observe the effect of Zhenjian granule (ZJG) on lowering the blood pressure and improving the essential hypertension (EH) and insulin resistance (IR). METHODS: Fifty-two hypertensive patients were randomly divided into the treated group (30 patients) with ZJG and the control group (22 patients) with captopril for 4 weeks, then the variation of levels of blood pressure, blood glucose, blood insulin (radioimmunoassay), insulin sensitivity index (ISI) and blood lipid before and after treatment were determined, and compared with the normal group (17 healthy subjects). RESULTS: Fasting insulin, blood glucose and insulin 2 hours after meal were significantly higher than those of the normal control, but the ISI was significantly lower than that of the normal control (P < 0.01), the insulin resistance existed; after treatment, not only the blood pressure obviously lowered (P < 0.05, P < 0.01), and the fasting insulin, blood glucose and insulin 2 hours after meal obviously lowered (P < 0.05, P < 0.01), ISI markedly raised (P < 0.05, P < 0.01). The IR of both groups was improved, the blood lipid of the treated group was also improved. CONCLUSION: ZJG was effective in reducing blood pressure, it also had significant effect on improving metabolic disorder, particularly on IR in EH patients.

Adult↗

PubMed2000

[The expression and effects of isoforms of macrophage colony stimulating factor in human leukemic cell lines].

OBJECTIVE: To explore the expression and effects of isoforms of macrophage colony-stimulating factor (M-CSF) in human leukemic cell lines. METHODS: Three normal human peripheral blood mononuclear cells (PBMCs) and 4 human myelomonocytic leukemic cell lines including J6-1, J6-2, K562 and HL-60 were studied using ABC immunoperoxidase assay, indirect immunofluorescence staining, flow cytometry, Western blot and reverse enzyme-linked DNA-protein interaction assay (reverse ELDIA). RESULTS: M-CSF was noticed to be localized in the cytoplasm, nucleus and at the cell membrane in 4 human leukemic cell lines; expression of M-CSF was not detected in normal human PBMCs without PHA stimulation. Human PBMCs stimulated by PHA expressed a low level of M-CSF. Frequencies of membrane bound M-CSF expression in J6-1, J6-2, K562 and HL-60 were 71.6%, 69.7%, 42.7% and 57.4% respectively. Frequencies of cytoplasm and nucleus associated M-CSF were 65.7%, 45.4%, 36.5% and 72.5% respectively. The cytosolic bound M-CSF was expressed in J6-1 cell as four isoforms with a molecular weight of 14,000, 16,000, 20,000 and 44,000. While nucleus associated M-CSF expressed as two isoforms with a molecular weight of 16,000 and 20,000. Anti-M-CSF monoclonal antibody could dramatically inhibit proliferation of leukemic cells and its inhibitory effect was related to the levels of membrane bound M-CSF expression in leukemic cells. Reverse ELDIA showed that M-CSF could bind with DNA in vitro. CONCLUSIONS: Expression of M-CSF isoforms is heterogeneous and polymorphous in leukemic cells. Membrane bound M-CSF is crucial for the proliferation of leukemic cells, which might be a DNA-bound protein and could be involved in the transformation and tumorigenesis of hematopoietic cells.

Antibodies, Monoclonal↗

PubMed2000

[Detection of minimal residual disease in childhood hematological malignancies and its clinical significance].

OBJECTIVE: Exploring the detection of minimal residual malignant cells in bone marrow from children with hematological malignancies to predict the prognosis. METHODS: Seventy-five patients with acute lymphoblastic leukemia (ALL), stage IV non-Hodgkin's lymphoma or stage IV neuroblastoma were studied. Complete remission was maintained for over 3 months before the detection. Minimal residual disease was detected by polymerase chain reaction (PCR) for IgH and TcRgamma rearrangements in lymphoid tumors by reverse transcriptase-polymerase chain reaction (RT-PCR) for neuroblastoma patients. RESULTS: Thirty five patients were positive for minimal residual disease, and 21 of them (60%) relapsed 3 - 40 months later, while only 7 (17%) negative patients relapsed (chi(2) = 12.59, P < 0.01). CONCLUSION: Minimal residual disease detection in bone marrow by PCR might predict prognosis in some childhood hematological malignancies.

Adolescent↗

PubMed2000

Quantitative study of basic fibroblast growth factor in vitreous with proliferative vitreoretinopathy.

OBJECTIVE: To quantitatively study basic fibroblast growth factor (bFGF) in the vitreous of proliferative vitreoretinopathy (PVR) in order to understand the role of bFGF in the development of PVR. METHOD: High sensitive sandwich enzyme immunoassay technique (ELISA) was used to measure bFGF level in vitreous of normal eyes, the eyes of PVR-C or PVR-D grade, eyes of vitreous hemorrhage and the serum levels of bFGF in PVR-D patients. RESULTS: The levels of bFGF in the vitreous were: median 5.20 ng/L, quartile 15.47 ng/L in 20 normal eyes; median 3.12 ng/L, quartile 10.48 ng/L in 35 PVR-C eyes; median 46.56 ng/L, quartile 113.96 ng/L in 26 PVR-D eyes; median 1.40 ng/L, quartile 6.25 ng/L in 25 vitreous hemorrhage eyes. The vitreous bFGF level in PVR-D group was significantly higher than that in the normal group, PVR-C group and vitreous hemorrhage group (P < 0.01). The mean of serum-bFGF level was 18.33 +/- 3.39 ng/L. The vitreous bFGF level of PVR-D group was significantly higher than serum-bFGF level (P < 0.01). And the vitreous-bFGF level in PVR-D group was significantly higher in larger retinal tear subgroup. CONCLUSION: The results suggested that bFGF is involved in the development of PVR.

Adult↗

PubMed2000

[Culture and identification of human vascular endothelial cells].

PURPOSE: To investigate the culture technigue of human vascular endothelial cells in vitro and improve the success rate of culture. METHODS: Human vascular endothelial cells were isolated from umbilical cords by "Irrigative digestion" technique with 0.2% collagenase III and were digested by 0.0625% tripsin when the cells confluent. The cells were identified by morphologic and immunohistochemical assays. RESULTS: The cultured human umbilical vein endothelial cells attached completely after 24 hours in vitro, reached confluence in 3-5 days with the typical appearance of "stone of pave road" and were passaged on time; Immunohistochemically these cells were stained positively by CD34 monoclonal antibody. CONCLUSION: "Irrigative digestion" technique was a reliable method to obtain human umbilical vascular endothelial cells with high success rate. It can be widely used to the culture and researches of human vascular endothelial cells.

Antibodies, Monoclonal↗

PubMed2000

[Detection of bcl-2/JH gene rearrangement by semi-nested polymerase chain reaction from fresh tumor samples in patients with laryngeal squamous cell carcinomas].

OBJECTIVE: To evaluate the clinical implications of bcl-2/JH gene rearrangement in laryngeal squamous cell carcinomas (LSCC). METHODS: Bcl-2/JH gene rearrangement analysis in fresh tumor samples was performed in 60 patients with LSCC by semi-nested polymerase chain reaction(PCR). RESULTS: The results showed that bcl-2/JH gene rearrangement was found in 37 out of 60 patients. The breakpoint was located within the major breakpoint region(mbr) in 33 of the 60 patients and the remaining patients had bcl-2 translocation within the minor cluster region(mcr). The results of the study showed that the rearrangement rate of bcl-2 gene was not related to the grade of differentiation, clinical stage, and neck lymph-node metastasis (P > 0.05), and it was related to heavy smoking (P < 0.05). CONCLUSION: Detection of bcl-2/JH gene rearrangement could reveal that bcl-2/JH fusion gene in LSCC is an important molecular biological marker and has a significant role in occurrence and development of LSCC.

Adult↗