Biomedical subjects

G Sun

Publications and source records attributed to G Sun.

At least 127 records · Page 7Linked to original sources

PubMed1999

[Experimental study and preliminary clinical application of bacterial collagenase in catabolizing scars].

OBJECTIVE: To investigate the mechanism of collagenase in degradation of hypertrophic scars and observe the clinical effects of this therapy. METHODS: Both animal experiment and clinical trial were conducted. RESULTS: The injection of collagenase into the hypertrophic scar tissues in nude mice resulted in 86% volume reduction after two injections within two weeks, while the control tissues reduced only by 35% during the same time. Clinically, 13 cases were treated with intralesional injection of bacterial collagenase. The volume reduction rate was 46.92% in average within two weeks. The volume reduction in 4 of 13 cases was above 50%. Three to sixteen months' follow-up of five patients revealed that only one case of keloid recurred after treatment in the second month. Examinations of histological sections and TEM showed the dissolved collagen fiber clearly. CONCLUSION: Collagenase can degrade collagen fiber directly. The prompt significant effects and the mild complications make it a prospective therapy.

Adolescent↗

PubMed1999

[Diagnosis and treatment of true hermaphroditism: a report of 3 cases and a review of literature].

OBJECTIVE: This paper evaluates the importance of early diagnosis and systemic treatment of true hermaphroditism. METHODS: Three patients with true hermaphroditism, because of inaccurate diagnosis and improper treatment at their early ages, were put in a dilemma when they grew up. After correct diagnosis, they accepted sex determinative operations according to their selective gender role. RESULTS: Through plastic operations, the three patients turned to be a male and two females, with their long time depression being released. CONCLUSION: True hermaphroditism is a rare deformity of ambiguous genitalia characterised by the presence of both ovarian and testicular tissues in the same individual. It is a key point for the patient to form normal sex psyche and adapt society through early precise diagnosis, appropriate gender option and successful operation according to clinical appearances and tissue pathological examination.

Adult↗

PubMed1999

Significant reduction of T-cell chemotaxis to MCP-1 in patients with primary and metastatic melanoma.

OBJECTIVE: To address whether circulating T-cells from the patients with primary and metastatic malignant melanoma show altered chemotaxis to monocyte-chemotactic protein 1 (MCP-1) and its relation to tumor infiltrating lymphocyte (TIL) and metastasis. METHODS: Chemotactic response of T-cells towards MCP-1 and immuno-histochemistry study of TIL and tumor-associated-macrophages (TAM) were investigated in patients with primary and metastatic melanoma compared to patients with basal cell carcinoma and healthy persons. RESULTS: T-cells from patients with primary and metastatic melanoma showed a significantly decreased chemotactic migration towards MCP-1 and T-cells from patients with basal cell carcinoma showed normal chemotactic response. Immuno-histochemistry study showed that there was no correlation between the number of TIL and the decreased chemotaxis of circulating T-cells to MCP-1 in patients with primary melanoma. CONCLUSIONS: Circulating T-cells from patients with primary and metastatic melanoma showed a MCP-1-specific decrease in chemotactic migration. This may be due to abnormal expression or modulation of MCP-1-receptor expression on these cells.

Adult↗

PubMed1999

[Effects of As2O3 on the BCR/ABL protein tyrosine phosphorylation in K562 cells].

OBJECTIVE: To explore the mechanisms of As2O3 inducing apoptosis and growth inhibition in K562 cells and provide theoretical basis for clinical application. METHODS: The effects of As2O3 on BCR/ABL protein tyrosine phosphorylation(PTP) and its signal transduction as well as the expression of apoptosis-related genes were studied by means of immunoprecipitation, Western blot, biochemical method and immunofluorescence. RESULTS: Tyrosine phosphorylation of several cellular proteins especially BCR/ABL protein was decreased by 1 mumol/L As2O3, but not by 0.1 mumol/L As2O3. As2O3 had no effect on PTP activity, downregulated the expression of JAK2 protein, but did not affect the expressions of STAT1 and STAT2 proteins and the STAT1 protein tyrosine phosphorylation. As2O3 had no effect on the expression of the apoptosis-related genes like Bcl-2, Bcl-xL/S, Bax, ICH-1L, p53, PARP, either, but downregulated PML protein expression in K562 cells. CONCLUSION: As2O3 might induce K562 cell apoptosis and inhibit its growth by reducing tyrosine phosphorylation of cellular proteins especially BCR/ABL protein and/or by downregulating JAK2 protein expression to interfere with the BCR/ABL protein signal transduction.

Antineoplastic Agents↗

PubMed1999

[The effects of sera of acute promyelocytic leukemia patients and culture supernates of NB4 cells on normal granulo-macrophage hematopoiesis].

OBJECTIVE: To explore the inhibitory activity of sera from acute promyelocytic leukemia(APL) patients on the growth of granular-macrophage progenitors(CFU-GM) and factors affecting the inhibitory activity. METHODS: Sera of 24 APL patients on the all-trans retinoic acid(ATRA) therapy course were kinetically obtained for cellular culture assay. Meanwhile, granulocyte-colony-stimulating-factor(G-CSF), interferon gamma and tumor necrosis factor(TNF) activities in the patient serum and supernate of NB4 cell culture were detected. RESULTS: Before treatment, there was an inhibitory activity on CFU-GM growth in the sera of APL patients and it was statistically higher than that in remission patients and controls(P < 0.01). As the treatment going on the activity was gradually increased, reached its maximum 3-6 days prior to the peak of white blood cell(WBC) and declined to normal when bone marrow remission was obtained. It was positively correlated with the number of CFU-L and the percentage of promyelocyte in bone marrow, negatively with the number of CFU-GM but not with serum G-CSF and TNF activity. Serum G-CSF level was positively correlated with the number of WBC (P < 0.05). No serum IFN-gamma activity was detected in the sera. CONCLUSIONS: 1. One of the therapeutic mechanisms of ATRA on APL is that ATRA induces APL cell maturation thus reduces the serum inhibitory activity on normal hematopoiesis. 2. The inhibitory activity of APL patient serum on normal hemopoiesis consists of complicated factors.

Antineoplastic Agents↗

PubMed1999

The relationship between the levels of granulocyte colony-stimulating factor and leukocytosis induced by all-trans retinoic acid in acute promyelocytic leukemia.

OBJECTIVE: To explore the mechanism of leukocytosis. METHODS: Enzyme linked immunosorbent assay (ELISA) method was used for detecting levels of serum granulocyte colony-stimulating factor (G-CSF) in 47 cases of acute promyelocytic leukemia (APL) during the treatment with all-trans retinoic acid (ATRA). RESULTS: The peak of increased serum G-CSF level occurred on the 9th day, and WBC number was the highest on the 11th day. After ATRA treatment, both serum G-CSF level and WBC number increased in 68.1% of the cases. In 19.2% of the cases treated, serum G-CSF level was increased but without obvious change in WBC number, and the reverse was true in 12.7% of the cases. CONCLUSION: Serum G-CSF level was statistically correlated to the number of WBC, promyelocytes and its late stage by Spearman's rank-order correlation coefficient.

Adolescent↗

PubMed1999

Differentiation therapy for acute promyelocytic leukemia with all-trans retinoic acid: 10-year experience of its clinical application.

PURPOSE: To summarize the experiences in using all-trans retinoic acid (ATRA) for the differentiation therapy for acute promyelocytic leukemia (APL) since our introduction of its use in clinic in 1986. DATA RESOURCES: Data resources came from Chinese Journal of Hematology, English-language literature using MEDLINE (1988-1998), book entitled "Treatment of Malignancies by Inducing Differentiation and Apoptosis" published by Shanghai Publishing House on Sciences and Technology, and our recent data to be published. STUDY SELECTION: Thirty-five articles related to the purpose of this review were reviewed. DATA EXTRACTION: Data were checked for their quality, reliance and originality. RESULTS: ATRA combined with chemotherapy can decrease the incidence of retinoic acid syndrome and produce a very high remission rate (90%-95%). Post-remission treatment should include chemotherapy and ATRA, the 5-year survival probability was able to attain 0.71 +/- 0.06. The main problem in the treatment is early tolerance to ATRA and relapse of the disease. The most effective treatments for relapsed APL is to use arsenic trioxide. CONCLUSION: The combination of ATRA, chemotherapy and arsenic oxide in the treatment of APL for elevating the remission rate and prolonging survival time deserves further study.

Antineoplastic Agents↗

PubMed1999

[The relationship of lung function and heart function of RHD patients in different period].

OBJECTIVE: To investigate the relationship of heart function and lung function in RHD patients. METHODS: We compared heart posterior-anterior film, lung function test results, PaO(2) and O(2) Sat of blood gas analysis before and after motion before operation, early postoperation, late postoperation, according to heart function and cardiothoracic ratio in 98 RHD patients. RESULTS: With worsening of heart function and enlargement of cardiothoracic ratio, lung function worsened too. PaO(2) and O(2) Sat did not change apparently. The lung function of early postoperation did not improve significantly. The lung function improved gradually with better heart function and shortening of heart in later postoperation. But small air way obstruction and diffuse function and function residue volume changed slowly. CONCLUSIONS: Heart function affects the lung function directly. They were positively correlated.

Adolescent↗

PubMed1999

[Prevalence of blindness among adults aged 50 years or above in Shunyi county of Beijing].

OBJECTIVE: To estimate the prevalence of blindness among older adults aged >or= 50 years in Shunyi county of Beijing, China. METHODS: Cluster sampling was used in randomly selecting individuals aged >or= 50 years in 28 villages in Shunyi county in fall, 1996. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. RESULTS: 5,555 individuals were enumerated. The response rate was 91.5%. In this population, the prevalence of blindness was 1.7% defined as pinhole visual acuity < 0.05 in both eyes; or 2.8% were blind, defined as presenting visual acuity < 6/60 in both eyes. Blindness was associated with older age and female gender. The principal cause of blindness in eyes was cataract. CONCLUSIONS: The prevalence of blindness was decreased 35.8% after ten year active eye-care program in the survey area. However, cataract blindness continues as a significant problem among elderly, especially females, in this population sample of rural area.

Age Factors↗

PubMed1998

[Identification of adhalin gene mutation in limb-girdle muscular dystrophy in Chinese].

OBJECTIVE: Limb-girdle muscular dystrophy (LGMD) is a group of severe genetic heterogeneity muscular diseases characterized by proximal muscular weakness of the pelvis and shoulder, affecting both male and female. This group of diseases involves four gene loci (13q12, 17q21,4q12,5q33). Up till now there is no research report about LGMD in Chinese. This study was intended to identify the pathogenic genes of LGMD in Chinese by mutation detecting. METHODS: The exons 2 and 3 of adhalin gene were analyzed in 13 Chinese LGMD patients and 20 controls by using PCR-SSCP and DNA sequencing. RESULTS: The R77C (Arg77Cys) missense mutation was found at the two alleles of a 9-year-old LGMD girl, which had not been found in the 40 wild type chromosomes. This is the first report on adhalin mutation that exists in LGMD in Chinese. CONCLUSION: Our results suggest that adhalin gene is one of the predisposing genes in LGMD in Chinese.

Child↗

PubMed1998

In search of the first flower: A jurassic angiosperm, archaefructus, from northeast china

Angiosperm fruiting axes were discovered from the Upper Jurassic of China. Angiosperms are defined by carpels enclosing ovules, a character demonstrated in this fossil. This feature is lacking in other fossils reported to be earliest angiosperms. The fruits are small follicles formed from conduplicate carpels helically arranged. Adaxial elongate stigmatic crests are conspicuous on each carpel. The basal one-third of the axes bore deciduous organs of uncertain affinities. No scars of subtending floral organs are present to define the individual fertile parts as floral units, but the leaf-like structures subtending each axis define them as flowers. These fruiting axes have primitive characters and characters not considered primitive.

Journal Article↗

PubMed1998

Autophosphorylation of Src and Yes blocks their inactivation by Csk phosphorylation.

Csk phosphorylates Src family protein tyrosine kinases on a tyrosine residue near their C-terminus and downregulates their activity. We previously observed that this regulation requires a stoichiometric ratio of Csk:Src in a time-independent manner. In this report we examined this unusual kinetic behavior and found it to be caused by Src autophosphorylation. First, pre-incubation of Src with ATP-Mg led to time-dependent autophosphorylation of Src, activation of its kinase activity and loss of its ability to be inactivated by Csk. However, the autophosphorylated Src can still be phosphorylated by Csk. The SH2 binding site for phospho-Tyr of this hyperactive and doubly phosphorylated form of Src is not accessible. Second, dephosphorylation of autophosphorylated Src by protein tyrosine phosphatase 1B allowed Src to be inactivated by Csk. Third, protein tyrosine phosphatase 1B preferentially dephosphorylates the Src autophosphorylation site and allows for Src regulation by Csk. Finally, Yes, another member of the Src family, was also only partially inactivated when a sub-stoichiometric amount of Csk was used. Mutation of the tyrosine autophosphorylation site of Yes to a phenylalanine resulted in a mutant Yes enzyme that can be fully inactivated by a sub-stoichiometric amount of Csk in a time-dependent manner. These results demonstrate that Csk phosphorylation inactivates Src and Yes only when they are not previously autophosphorylated and Src autophosphorylation can block the inactivation by Csk phosphorylation. This conclusion suggests a dynamic model for the regulation of the Src family protein tyrosine kinases, which is discussed in the context of previously reported observations on the regulation of Src family protein tyrosine kinases.

CSK Tyrosine-Protein Kinase↗

PubMed1998

Identification of a novel growth factor-like lipid, 1-O-cis-alk-1'-enyl-2-lyso-sn-glycero-3-phosphate (alkenyl-GP) that is present in commercial sphingolipid preparations.

Lysophosphatidic acid, a member of the acidic phospholipid autacoid (APA) family of lipid mediators, elicits diverse cellular effects that range from mitogenesis to the prevention of programmed cell death. Sphingosine 1-phosphate and sphingosylphosphorylcholine have also been proposed to be ligands of the APA receptors. However, key observations that provide the foundation of this hypothesis have not been universally reproducible, leading to a controversy in the field. We provide evidence that 1-O-cis-alk-1'-enyl-2-lyso-sn-glycero-3-phosphate (alkenyl-GP) is present in some commercial sphingolipid preparations and is responsible for many of their APA-like effects, which were previously attributed to sphingosylphosphorylcholine. Alkenyl-GP was generated by acidic and basic methanolysis from ethanolamine lysoplasmalogen, which was present in the sphingomyelin fraction that is used to manufacture sphingosylphosphorylcholine. We present the structural identification of alkenyl-GP, using 1H and 13C NMR, Fourier transform infrared spectrometry, and mass spectrometry. Alkenyl-GP was a potent activator of the mitogen-activated protein kinases ERK1/2 and elicited a mitogenic response in Swiss 3T3 fibroblasts. In contrast, sphingosylphosphorylcholine at a concentration of 10 microM was only a weak mitogen and only weakly activated the extracellular signal-regulated protein kinases. Alkenyl-GP has recently been detected as an injury-induced component in the anterior chamber of the eye (Liliom, K., Guan, Z., Tseng, H., Desiderio, D. M., Tigyi, G., and Watsky, M. (1998) Am. J. Physiol. 274, C1065-C1074), indicating that this lipid is a naturally occurring member of the APA mediator family.

3T3 Cells↗

PubMed1998

Design and synthesis of enantiomers of 3,5-dinitro-o-tyrosine: alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid (AMPA) receptor antagonists.

The R- and S-isomers of 3,5-dinitro-o-tyrosine (6a,b) have been synthesized through the use of chemoenzymatic synthesis and shown to bind differentially with the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid (AMPA, 3) receptors. The phenolic functional group of these o-tyrosine analogues was designed to act as a bioisostere of the gamma-carboxyl group of glutamate. The S-isomer of 3,5-dinitro-o-tyrosine (6b) was 6.5 times more potent than the R-isomer (6a) in inhibiting [3H]AMPA binding with IC50 values of 13 +/- 7 and 84 +/- 26 microM, respectively. The phenolic group was important for binding affinity since the methoxy compound 7 was less potent than the phenolic compound 6 in inhibiting the binding of AMPA. The free amino group was also shown to be important since the N-acetyl analogue 15 and the N-t-BOC compounds 16 and 17 exhibited very low affinity for the AMPA receptors. AMPA receptor functional tests showed that the o-tyrosine analogues are antagonists and that the S-isomer 6b (IC50 = 630 +/- 140 microM) was more potent than the racemate 6 (IC50 = 730 +/- 88 microM) while the R-isomer 6a was inactive up to 1 mM concentration, which is consistent with the S-isomer having higher binding affinity than the R-isomer.

Animals↗

PubMed1998

Molecular features associated with polyamine modulation of NMDA receptors.

The effect of 1,3-diamines on basal and spermine-stimulated [3H]MK-801 binding was investigated. Systematic variations in the molecular parameters revealed that, in general, lipophilic 1,3-diamines inhibited and hydrophilic 1,3-diamines enhanced [3H]MK-801 binding in the nominal absence of glutamate and glycine. Furthermore, 1,3-diamines which were highly monoprotonated at physiologic pH were more effective in modulating basal binding (at 100 microM 1,3-diamine) than analogues which were mostly diprotonated or unprotonated. Finally, the internuclear distance between the amino nitrogens and the extent of modulation of basal [3H]MK-801 binding were correlated. Similar, but more modest, effects were seen for spermine-enhanced [3H]MK-801 binding. These results are consistent with the existence of two polyamine binding sites associated with the NMDA receptor complex. One of the sites appears to preferentially recognize lipophilic substances while the other favors hydrophilic materials. Both sites appear to recognize polyamines with at least one charged (protonated) amino group and one uncharged amino group. The distance between amino groups is a determining factor as well.

Animals↗

PubMed1998

Toxicity of intraocular lidocaine and bupivacaine.

PURPOSE: To study the toxicity of intraocular lidocaine, bupivacaine, and a combination of the two anesthetics. METHODS: The right eyes of 34 rabbits were divided into eight groups, and each was injected intravitreally with 0.2 ml of lidocaine hydrochloride in a 2%, 1%, 0.5%, or 0.25% concentration, or bupivacaine hydrochloride in a 0.75%, 0.5%, or 0.25% concentration, or a 1:1 mixture of lidocaine 2% and bupivacaine 0.75%. The left eyes of four of these rabbits received an injection of balanced saline solution. Electroretinograms were recorded before injection and 30 minutes, 90 minutes, 3 hours, 6 hours, 24 hours, and 1 week after injection. The amplitude and the implicit time were analyzed. The rabbits were killed 1 week after injection and the eyes evaluated histologically. RESULTS: No adverse clinical reaction and no histologic abnormality was observed in any of the nine groups after injection. The a- and b-waves of the electroretinograms in the control group injected with balanced saline solution, and the a-waves of the experimental groups that received injections of lidocaine, bupivacaine, or the mixture, were normal. The b-waves of the experimental groups demonstrated a marked decrease in the amplitude and an increase (P < .05) in the implicit time after intravitreal injection. Electroretinogram responses recovered within 24 hours. CONCLUSIONS: Intravitreal injection of 0.2 ml of lidocaine up to 2%, or of bupivacaine up to 0.75%, and the mixture of lidocaine 2% and bupivacaine 0.75%, induced reversible electroretinogram changes in the rabbit retina. No histologic abnormalities were observed.

Anesthetics, Local↗

PubMed1998

Kinetics of eotaxin expression and its relationship to eosinophil accumulation and activation in bronchial biopsies and bronchoalveolar lavage (BAL) of asthmatic patients after allergen inhalation.

We investigated the kinetics of allergen-induced eotaxin expression and its relationship to eosinophil accumulation and activation in the airways of patients with allergic asthma. Twenty-four patients with allergic asthma and late asthmatic responses to allergen inhalation were randomly allocated into three groups of eight patients each, who received bronchoscopy with bronchial biopsies and BAL at 2, 4 and 24 h, respectively, after the inhalation of the diluent and the allergen. The expression of eotaxin mRNA and protein and eotaxin release were evaluated by in situ hybridization, immunohistochemistry, immunocytochemistry, and radioimmunoassay. Increased transcription from the eotaxin gene preceded the appearance of the late asthmatic response and the influx of activated eosinophils in bronchial tissue and BAL fluid (BALF). This was followed by increased cell expression of eotaxin protein (P<0.001) and increased eotaxin release (P<0.001), which correlated with the numbers of total and activated eosinophils and the level of airflow obstruction at 4 h after allergen exposure (P<0.05 for all correlations). At 24 h after allergen inhalation, enhanced eotaxin expression declined without a similar reduction in the numbers of eosinophils in bronchial biopsies and when there was a further increase in the number of these cells in BALF (P<0.05). These results indicate that eotaxin contributes to the early phase of allergen-induced recruitment of activated eosinophils into the airways of patients with allergic asthma and that other factors are implicated in the persistence of eosinophil infiltration.

Administration, Inhalation↗

PubMed1998

Cellular and molecular characteristics of inflammation in chronic bronchitis.

METHODS: To examine the inflammatory process in chronic bronchitis, we evaluated the cell and cytokine profile in bronchoalveolar lavage fluid from 12 chronic bronchitis patients who smoked, six chronic bronchitis patients who did not smoke, 10 subjects control subjects without pulmonary diseases who smoked and eight control subjects who did not smoke. RESULTS: Chronic bronchitis patients who smoked had increased numbers of macrophages, neutrophils, eosinophils, mast cells and activated CD8+ T lymphocytes and predominantly expressed interleukin-8, tumour necrosis factor alpha and interleukin-2 genes and proteins. The number of macrophages and neutrophils and the expression of interleukin 8 were also increased in control subjects who smoked compared with healthy subjects who did not smoke. Chronic bronchitis patients who did not smoke had increased numbers of eosinophils, mast cells and activated CD4+ T lymphocytes and predominantly expressed interleukin-5 and granulocyte-macrophage colony-stimulating factor genes and proteins. CONCLUSION: Thus, the cellular and molecular characteristics of the inflammatory process in chronic bronchitis patients who smoke and do not smoke are different, suggesting a different pathogenesis of the disease.

Adult↗