Biomedical subjects

X Shen

Publications and source records attributed to X Shen.

At least 127 records · Page 7Linked to original sources

PubMed1999

Relationship between remodeling and function of left ventricle and angiotensin II AT1 receptor expression after myocardial infarction in rats.

OBJECTIVE: To determine the relationship between remodeling and dysfunction of left ventricle (LV) and the expression of the angiotensin II AT1 receptor mRNA after myocardial infarction (MI) in rats. METHODS: Nine MI rats (Group A) and 8 sham-operated rats (Group B) were studied by both Doppler echocardiography and Dot blot using Digoxingenin-labelled cDNA probes. RESULTS: Compared with Group B, Group A showed the increase in LV internal diastolic diameter (0.87 +/- 0.06 mm vs 0.66 +/- 0.03 mm, respectively, P < 0.01) and volume (0.73 +/- 0.09 ml vs 0.51 +/- 0.05 ml, P < 0.01). In addition, thinning of anterior wall, thickening of posterior wall, increasing of peak early filling velocity (peak E), decreasing of late filling velocity (peak A) and increasing of the E/A were demonstrated in MI rats 7 weeks after MI. The levels of the cardiac angiotensin II AT1 receptor mRNA in Group A were higher than those of Group B (2.2-fold). CONCLUSIONS: Seven weeks after MI in rats, character of LV remodeling and dysfunction were developed and the expression of cardiac angiotensin II AT1 receptor mRNA was increased.

Animals↗

PubMed1999

[Comparison of children's blood lead levels in Shanghai before and after the introduction of lead free gasoline].

OBJECTIVE: To determine the blood lead levels of children before and after the introduction of lead free gasoline in Shanghai. METHODS: We measured the blood lead levels in 1972 children in Shanghai before the introduction of lead free gasoline in Shanghai. The blood lead levels of those children were re-determined 6 months after the leaded gasoline was phased out. RESULTS: After leaded gasoline was phased out, geometric mean of blood lead levels was decreased significantly from 83 micrograms/L to 80 micrograms/L. The prevalence rate of childhood lead poisoning (blood lead level equal to or more than 100 micrograms/L) decreased from 37.8% to 25.7%. CONCLUSIONS: The introduction of lead free gasoline could decrease children's blood lead levels in Shanghai. However, the magnitude of decrease is not as great as expected, suggesting that more environmental interventions, such as industry emission control, are needed to prevent childhood lead poisoning.

Child↗

PubMed1999

[Detection and evaluation of bcl-x and bcl-2 gene expression in blasts from patients with acute leukemia].

OBJECTIVE: To investigate the expression of bcl-x and bcl-2 genes in bone marrow cells of acute leukemia and their effects on response to chemotherapy. METHODS: Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the mRNA expressions of bcl-xL, bcl-xs and bcl-2 in blast cells from 34 acute leukemia(AL) patients. RESULTS: The expression of bcl-xL and bcl-2 or both in blast cells from 34 AL patients was higher than that in complete remission patients and normal subjects. The expression of bcl-xL and bcl-2 in relapsed patients was increased by 1.8 and 1.9 fold, respectively, compared with that in the newly diagnosed patients(P < 0.01). However, no relationship was found between the expression of bcl-xs and the relapse and chemotherapeutic response of the AL patients. There were positive correlations between the expression of bcl-xL and bcl-2 or bcl-xL and bcl-xs. The expression level of bcl-xL and bcl-2 in the patients with poor response to chemotherapy was significantly higher than that in the patients with better response. Treatment failure occurred in 80.0%, 91.7% and 100.0% of the patients with overexpression of bcl-xL and bcl-2 and both, respectively. CONCLUSION: Overexpression of bcl-xL and bcl-2 may imply the lower sensitivity of the leukemic cells to chemotherapy and higher risk of relapse.

Adolescent↗

PubMed1999

[Effect of tongbiling on synoviocyte function in adjuvant arthritis rats].

OBJECTIVE: To study the effect of Tongbiling (TBL) on the proliferation of synovial fibroblast and interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha) and postaglandin E2(PGE2) secretion by synoviocytes in adjuvant arthritis (AA) rats. METHODS: Synovial fibroblasts was derived from culture of tissue piece. The effect of primary synoviocyte culture supernatants on the fibroblast proliferation were assayed and IL-1, TNF-alpha bioactivity and PGE2 content of supernatants of cultured synoviocytes were measured. RESULTS: TBL could inhibit significantly the synovial fibroblast proliferation (P < 0.001), and down-regulated IL-1, TNF-alpha and PGE2 productions (P < 0.01); indomethacin could promote obviously the synovial fibroblast proliferation (P < 0.001). It inhibited significantly PGE2 production, but further up-regulated the IL-1 and TNF-alpha secretion by synoviocytes (P < 0.01). CONCLUSION: The therapeutical effect of TBL on AA might be associated with its down-regulating the secretory function of synoviocyte, then restoring the abnormal proliferation of fibroblast to normal levels.

Animals↗

PubMed1999

[Surgical treatment of dissecting aneurysm of the interventricular septum].

OBJECTIVE: To report a kind of extremely rare disease, dissecting aneurysm of the interventricular septum. METHODS: Between May 1992 and January 1998, 4 patients underwent surgical treatment of dissecting aneurysm of the interventricular septum in Fuwai Hospital, Beijing. The cause of the disease was different in these four patients. Two patients may be attributable to the aneurysm of coronary sinus of valsava, 1 to the result of trauma, and the other to big perforation (diameter: 2 cm) in the bottom of the right coronary sinus of valsava, through which the blood rushed into the cavity of dissecting aneurysm of the interventricular septum. The aneurysm was resected or repaired in these patients. Three of them were subjected to aortic valve replacement and one received repair of the perforation of the right vaslava sinus. RESULTS: Two patients had successful reoperation and the other 2 suceeded in the first operation. All of them were uneventfully recovered. CONCLUSIONS: The development of dissecting aneurysm of the interventricular septum is rapid. Its prognosis is poor. Early diagnosis and operation are necessary. The pathogenic mechanism of dissecting aneurysm of the interventricular septum is unknown, but echocardiogram, electrocardiogram and nuclear magnetic resonance (NMR) are valuable for diagnosis. Surgical operation should involve the treatment of aortic valve disease. The wall of the aneurysm should be resected and the interventricular septum should be reconstructed. Good exposure can be obtained from the incision of the ascending aorta and right ventricular outflow tract. The A-V block should be treated simultaneously.

Adult↗

PubMed1999

[A study on relationship between blood lead level and physical growth and development of babies and young children in Shanghai].

OBJECTIVE: To study the effects of low level lead exposure on physical growth and development in young children. METHODS: Blood lead level and indicators for physical growth and development, such as body height and weight, and head and chest circumferences were measured in randomly sampled 1,969 children aged 1 - 6 years in Shanghai. Z scores for these indicators were calculated for each of them based on their age and sex-specific norms for children in urban and suburban Shanghai. And, regression analysis of blood lead level was conducted on them. RESULTS: Geometric mean of blood lead level was 0.400 micromol/L in young children of Shanghai, and 744 (37.8%) of 1,969 children were equal to or higher than 0.483 micromol/L. Geometric mean of blood lead level correlated in reverse to the Z scores for their body height, weight and head circumference, even if adjusted for the potential confounding factors. CONCLUSION: Low level lead exposure could cause adverse effects on their physical growth and development in young children of Shanghai.

Body Height↗

PubMed1999

[Effect of fluoride exposure on synaptic structure of brain areas related to learning-memory in mice].

The learning-memory behavior was tested in mice on a Y-maze after drinking different concentration of sodium fluoride. The impairment on the structure of Gray 1 synaptic interface in the CA3 area of mice hippocampus were quantitatively analyzed by electron microscopy and computer image processing appliance. The main results are as follows: the learning ability of mice drinking high concentration of fluoride presented remarkable deterioration, the thickness of post-synaptic density (PSD) was decreased, and the width of synaptic cleft was remarkably increased. The results suggested that the impairment on the learning capability induced by fluorosis may be closely related with the pathological changes of synaptic structure in the brain of mice.

Animals↗

PubMed1999

[Single-catheter approach to radiofrequency current ablation of accessory pathway in Wolff-Parkinson-White syndrome with recurrent rapid atrial fibrillation].

Twelve patients with WPW were treated by single-catheter ablation. Eight patients had the histories of recurrent rapid atrial fibrillation(Af) and refractory to antiarrhythmic agents. Ventricular rate varied between 250-300 bpm. Defibrillation was needed in three patients, and one had syncope. All patients were treated successfully by ablation of accessory pathway with single-catheter approach and no Af occurred during the procedures. This result suggests that the single-catheter ablation may be an effective and feasible treatment for these patients with WPW and may be helpful in avoiding Af in multiple-catheter introducing procedure.

Adult↗

PubMed1999

[Study on combined clinical manifestation and myocardial perfusion imaging with 99mTc-MIBI SPECT for diagnosing myocarditis].

In 568 cases suffering from upper-respiratory tract infection with sore throat and more than one of following clinical manifestations: arrhythmia, heart failure and chest pain or oppressive sensation over the chest(Group A), and another 108 cases without above clinical manifestations(Group B), myocardial perfusion imaging with 99mTc-MIBI SPECT was studied. The results revealed that the imaging in 404 cases (71.12%) of Group A supported diagnosis of myocarditis, but only 6 cases(5.56%) did so in Group B. Because of lacking the clinical manifestations of myocarditis but positive finding of CVB-IgM antibody was detected in their sera, we considered that the positive SPECT imaging in these six cases of Group B belonged to myocardial reaction due to virus infection. It was possible that some of them were suffering from subclinical type of myocarditis.

Adolescent↗

PubMed1999

[Analysis of 16 cases with aggressive fungal maxillary sinusitis].

OBJECTIVE: To improve the diagnosis and treatment level of aggressive fungal maxillary sinusitis. METHOD: 16 cases were diagnosed with CT. Caldwell-Luc's surgery was done in 13 cases and Lima surgery in 3 cases. None of them were treated by antifungal agents. RESULT: It showed osteolytic damage with bony defect which was different from expanded bony defect caused by benign tumor, but similar to malignant tumor. No recurrence occurred as followed from 6 months to 2 years. CONCLUSION: Computed tomography is very important in its diagnosis. Early explorative operation is useful in making definite diagnosis.

Adult↗

PubMed1999

[The relationship between fMLP induced neutrophil respiratory burst and the apoptosis of neutrophil].

The relationship between apoptosis of neutrophils and the change of their intracellular free Ca2+ concentration [Ca2+]i was studied. FMLP and A23187 were used to elevate the [Ca2+]i while BAPTA was used to deplete it. Fluorescence microscope, flow cytometry and gel electrophoresis were used to study the percentage of cell apoptosis and the change of f-actin during apoptosis. The results showed that the apoptosis was obviously inhibited by fMLP and A23187, while accelerated by BAPTA. The detection of f-actin showed that the f-actin depolymerized obviously during apoptosis. The elevation of [Ca2+]i inhibit the actin depolymerization while depletion of [Ca2+]i accelerated it. This result indicated that the apoptosis of neutrophil was obviously inhibited by [Ca2+]i elevation but accelerated by [Ca2+]i depletion.

Apoptosis↗

PubMed1999

[Expression of Schistosoma japonicun fatty acid binding protein gene in silkworm cells and larvae].

AIM: To express the fatty acid binding protein (Sj14FABP) gene of Schistosoma japonicun in the silkworm cells and larvae. METHODS: A 600 bp DNA fragment containing Sj14FABP gene was cloned into baculovirus transfer vector of pBacPAK His1 to construct recombinant transfer vector Sj14-pBac PAK His1. Coinfection was accomplished with this vector and Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA in BmN cells. The recombinant virus of Bm-Sj14 was screened using dot-blotting. The BmN cells and silkworm larvae were infected with Bm-Sj14 to express Sj14FABF gene. Western blotting and ELISA were used to identify the antigenicity of the recombinant protein. RESULTS: Sj14FABP gene was successfully expressed in the BmN cells and silkworm larvae infected with Bm-Sj14. The product was a 18 kDa fusion protein. The yield in BmN cells was about 100 micrograms/1 x 10(6) cells and 33 micrograms/ml cell supernatant. In silkworm larvae, the product yield was 4 mg/ml haemolymph as well as 4.6 mg/g silkworm tissue. The recombinant protein could be recognized by Western blotting and ELISA using the sera from mice immunized with SWAP. CONCLUSION: Sj14FABP gene has been successfully expressed in BmNPV system and the product has high antigenicity.

Animals↗

PubMed1999

GnRH agonist. Increasing the pregnancy rate after combined treatment with hMG/hCG and direct intraperitoneal insemination.

OBJECTIVE: To evaluate the efficacy of the GnRH agonist (GnRHa) administered in conjunction with human menopausal gonadotropin/human chorionic gonadotropin hMG/hCG and direct intraperitoneal insemination (DIPI) in women with long-standing unexplained infertility. STUDY DESIGN: A prospective, randomized, non-blind analysis. During the period May 1995-December 1996, couples with unexplained infertility who failed to conceive following superovulation combined with IUI for at least seven cycles were prospectively enrolled and followed. Pregnancy rates per cycle and per patient of DIPI were compared between groups of hMG/hCG with (GnRHa[+] controlled ovarian hyperstimulation [COH] group) or without (GnRHa[-] COH group) GnRHa. RESULTS: Thirty-four women (59 cycles) underwent COH with hMG and GnRHa, and 31 women (49 cycles) received hyperstimulation with hMG alone. The pregnancy rates for the women administered GnRHa significantly exceeded those of the patients who did not receive GnRHa both per treatment cycle (35.6% versus 14.3%) and per couple (55.9% versus 22.5%). CONCLUSION: The use of GnRHa with hMG/hCG and DIPI treatment significantly increased the pregnancy rate in women with long-standing infertility.

Adult↗

PubMed1998

Selection and function of CD4+ T lymphocytes in transgenic mice expressing mutant MHC class II molecules deficient in their interaction with CD4.

Interactions of the T cell coreceptors, CD4 and CD8, with MHC molecules participate in regulating thymocyte development and T lymphocyte activation and differentiation to memory T cells. However, the exact roles of these interactions in normal T cell development and function remain unclear. CD4 interacts with class II MHC7 molecules via several noncontiguous regions in both the class II MHC alpha- and beta-chains. We have introduced a double mutation that disrupts interaction with CD4 into the I-A(beta)k gene and used this construct to generate transgenic mice expressing only mutant class II MHC. Although CD4+ thymocytes matured to the single-positive stage in these mice, their frequency was reduced by threefold compared with that of wild-type transgenics. Positive selection of CD4+ T cells in the mutant transgenic mice may have been mediated by TCRs with a higher than usual affinity for class II MHC/Ag complexes. In A(beta)k mutant transgenics, peripheral CD4+ lymphocytes promoted B cell differentiation to plasma cells. These CD4+ T cells also secreted IFN-gamma in response to various stimuli (e.g., protein Ag, bacterial superantigen, and alloantigen), but were deficient in IL-2 secretion. Interactions between CD4 and class II MHC molecules appeared to regulate lymphokine production, with a strong bias toward IFN-gamma and against IL-2 in the absence of these interactions. Our results have implications for the manipulation of T cell-dependent immune responses.

Amino Acid Substitution↗

PubMed1998

Extracellular Ca2+ regulates the respiratory burst of human neutrophils.

The role of extracellular calcium in the activation of respiratory burst in human neutrophils was studied by using the receptor agonist, N-formyl-methionyl-leucyl-phenylalanine (fMLP), and the activator of protein kinase C phorbol myristate acetate (PMA). The level of intracellular free calcium was measured by using both cell suspensions and single cells in the presence and absence of extracellular calcium. The Ca2+-ATPase inhibitor, thapsigargin, was used to activate higher Ca2+ influx, while a novel calcium channel blocker, panax notoginseng saponins (PNGS) was used to block the Ca2+ entry from extracellular space during the responding period of cells. It was found that about two-thirds of the activation of respiratory burst initiated by the receptor agonist were attributed to the Ca2+ influx under normal physiological conditions. The higher Ca2+ influx resulted in tremendous enhancement of the intensity of respiratory burst initiated by fMLP and marked acceleration of the onset of the respiratory burst stimulated by PMA. It is evident that both intra- and extracellular Ca2+ are required for full activation of the respiratory burst of human neutrophils, and the Ca2+ influx from extracellular space plays an important role either in generation of reactive oxygen metabolites or in activation of protein kinase C.

Calcium↗

PubMed1998

Characterization of carbohydrates using a combination of derivatization, high-performance liquid chromatography and mass spectrometry.

A combination of derivatization methods, chromatographic techniques and mass spectrometric ionization modes have been explored for the characterization of small sugars and medium-size oligosaccharides. Derivatization using 1-phenyl-3-methyl-5-pyrazolone (PMP) was preferred over pyridylamination (PA) owing to the simplicity of the reaction method, and also to enhanced ionization efficiency of the PMP derivatives relative to aminopyridyl sugars. The good quality and ease of separation of PMP derivatives by high-performance liquid chromatography were also advantages of using PMP derivatization rather than pyridylamination. PMP- and PA-monosaccharides produced abundant ions by either fast atom bombardment (FAB), electrospray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI). The PA and PMP derivatives of lactose, fucosyllactose and sialyllactose yielded FAB spectra with low S/N ratios, whereas ESI and MALDI produced better spectra with a hundredth of the material used for FAB. In general, PMP derivatives of these di- and trisaccharides gave rise to stronger signals than PA analogs. For Oligosaccharides containing more than three sugar rings, only PMP was used for derivatization, FAB was dropped and only ESI and MALDI were utilized.

Carbohydrates↗

PubMed1998

Sp1, but not Sp3, functions to mediate promoter activation by TGF-beta through canonical Sp1 binding sites.

Transforming growth factor beta (TGF-beta) causes growth arrest at the G1 phase of the cell cycle in most cell types. Both the cyclin dependent kinase inhibitor p15(INK4B) and p21(Cip1/WAF1) genes have been found to be induced by TGF-beta in human keratinocyte HaCaT cells. Analyses of the human p15 and p21 promoters have led to the identification of GC-rich sequences capable of binding to Sp1 transcription factors as necessary elements for the TGF-beta induction of both promoters. We report here that canonical Sp1 binding sites derived from the SV40 21 bp repeat could also support promoter induction by TGF-beta when placed upstream of a minimal luciferase reporter construct containing only the TATA and Inr elements. Gel retardation assays identified Sp1, Sp3 and DeltaSp3 as major factors binding to the canonical Sp1 sites in HaCaT cells and that TGF-beta treatment did not change their binding activities over a 24 h period. More importantly, GAL4-Sp1, but not GAL4-Sp3, chimeric protein supported TGF-beta mediated gene induction from a luciferase reporter construct driven by five GAL4 DNA binding sites. Our results suggest that Sp1 binding site can function as a distinct TGF-beta responsive element for TGF-beta mediated promoter expression and Sp1 per se can mediate this response.

Adenovirus E1A Proteins↗

PubMed1998

Attachment, morphology, and protein expression of rat marrow stromal cells cultured on charged substrate surfaces.

Although surface charge has been shown to affect the adhesion and morphology of a variety of cell types, the interactions of bone marrow stromal cells with charged surfaces still remain unclear. A novel electrical stimulation system was used to investigate the interactions between rat bone marrow stromal cells and charged substrates in this study. A conductive and transparent indium tin oxide (ITO) coating was used as an electret substrate. Rat marrow stromal cells were cultured on positive, negative, and uncharged ITO surfaces. Cell attachment, morphology, alkaline phosphatase activity, and expression of osteopontin and collagen type III were assessed using histochemical staining, immunolabeling, and fluorescence microscopy. Voltages of 0.7, 0.8, 0.9, and 1.0 V applied to the substrates created surface potentials but were insufficient to decompose the media. On positively charged ITO, cell attachment was enhanced in serum-supplemented and serum-free media. Furthermore, decreases in cell spreading, alkaline phosphatase activity, and osteopontin were observed in cells grown on the positively charged ITO. These data indicate that positively charged surfaces enhance cell attachment but suppress cell spreading and differentiation of rat marrow stromal cells.

Alkaline Phosphatase↗