Biomedical subjects

Rui Ma

Publications and source records attributed to Rui Ma.

30 records · Page 2Linked to original sources

PubMed2005

[Study on the descriptive epidemiology of pregnancy-induced hypertension from 1995 - 2000 in Jiaxing of Zhejiang province, China].

OBJECTIVE: To describe the epidemiological characters of pregnancy-induced hypertension (PIH) in Jiaxing areas of Zhejiang province of China between 1995 and 2000. METHODS: We analyzed the perinatal health surveillance data that was collected as part of the Sino-American cooperative project on neural tube defects prevention established in 1992. The study population consisted of 136 070 pregnant women with at least 20 weeks of gestational age. National diagnostic criteria were used to identify the cases which were divided into three subgroups: mild, moderate and severe. RESULTS: 15 127 cases were identified and the overall incidence rate of PIH was 11.1% (95% CI : 11.0% - 11.3%). Among all the cases, mild, moderate and severe PIH were accounted for 71.4%, 22.3% and 6.3%, respectively. The proportions of PIH cases that occurred in the second trimester, third trimester and during delivery appeared to be 4.2%, 34.4% and 61.4%, respectively. There was a significant fall in the trend of PIH occurrence every year, which dropped from 10.7% in 1995 to 8.6% in 2000 by 19.6%. More risk of PIH seemed to be related to those mothers living in the urban areas with age under 20 or above 35, being peasants and having little educational, having had multiple gestations, conceiving in spring/summer or delivering in winter or spring etc. Compared with the results of national survey in 1988, the incidence rate of PIH was higher by 18.1%, while the proportion of severe PIH was much lower by 68.8%. Although the incidence rates of PIH in urban and rural areas were somehow similar, the proportion of severe PIH in rural areas was much higher than that in urban areas. CONCLUSION: Overall incidence rate and distribution of PIH were reported. Compared with the results in 1988, incidence rate of PIH was much higher, particularly for mild cases.

Adult↗

PubMed2004

Homologous up-regulation of androgen receptor expression by androgen in vascular smooth muscle cells.

OBJECTIVE: Androgens play an important role in the arterial vascular system, and androgen receptors (AR) have been identified in vascular smooth muscle cells (VSMCs). This study examined the effects of testosterone exposure on AR gene expression in cultured rat aortic smooth muscle cells. METHODS: Changes in AR protein and messenger RNA (mRNA) levels after androgen exposure were determined using immunoblotting and Northern blotting analysis respectively. RESULTS: Treatment of synchronized VSMCs with testosterone increased both cytoplasmic and nuclear AR protein expression in a dose- and time-dependent fashion, whereas exposure of VSMCs to androgen for 10 min induced a transient down-regulation of AR protein. Meanwhile, AR mRNA level was also up-regulated, but to a much smaller extent. Pretreatment with transcription inhibitor and translation inhibitor repressed cytoplasmic AR protein levels to 46 and 12% (means) of the androgen treatment control level respectively. Furthermore, androgen up-regulation of intracellular AR protein was partially inhibited by androgen antagonist. CONCLUSIONS: Androgen increases AR expression in VSMCs at the level of both transcription and non-transcription.

Animals↗

PubMed2004

Systemic induction of traumatic resin ducts and resin flow in Austrian pine by wounding and inoculation with Sphaeropsis sapinea and Diplodia scrobiculata.

The potential role of the resin system in the response of Austrian pine (Pinus nigra Arn.) seedlings to mechanical injury and fungal infection was studied in greenhouse experiments. Anatomical observations were performed on 2-year-old plants wounded at collar level and inoculated with Sphaeropsis sapinea (Fr.: Fr.) Dyko & Sutton in Sutton or Diplodia scrobiculata (J. de Wet, B. Slippers & M. J. Wingfield, sp. nov.; sensu de Wet et al. 2003), two fungal pathogens that cause shoot blight and canker on conifers, and that are characterized by different levels of aggressiveness. Histological examination of host tissue taken from the stem at 0, 8, and 12 cm above the treatment site revealed significant treatment- and time-dependent effects on the course of locally and systemically induced traumatic resin duct (TRD) development. Occurrence of TRDs was observed after 4 days only in seedlings inoculated with D. scrobiculata. At 12 days, TRDs were present also in mock-inoculated controls. No TRDs appeared in seedlings inoculated with S. sapinea. However, S. sapinea caused loss of vacuolar phenolics, severe disruption of cambial tissue and invaded the host xylem quickly and apparently unimpeded, whereas D. scrobiculata was never detected in the host xylem. Five-year-old Austrian pines subjected to the same stem base treatments were used to determine the resin mass flowing from the stem 30 cm above the treatment sites. Wounding and/or inoculation induced a significant, 8.3-fold average increase in systemic resin flow over the untreated trees 3 weeks after basal treatment, suggesting that wounding is the sole prerequisite for systemic induction of resin flow. The results are discussed in the context of current disease resistance models.

Ascomycota↗

PubMed2004

[Testosterone regulation of androgen receptor protein expression in cultured vascular smooth muscle cells].

OBJECTIVE: To investigate the effects of testosterone exposure on androgen receptor (AR) protein expression in vascular smooth muscle cells (VSMC) and the possible mechanisms mediating the effects. METHODS: VSMC were cultured from thoracic aorta of male Sprague-Dawley rats by using the explant method. Cytoplasmic and nuclear extracts were prepared by means of cell lysis and high salt extraction respectively, and subjected to western blotting analysis for determination of AR protein level. RESULTS: Treatment of synchronized VSMC with testosterone increased both cytoplasmic and nuclear AR protein expression in a dose (0 - 4 micro mol/L) and time (1 - 48 h)-dependent fashion, whereas exposure of VSMC to testosterone at a physiologically relevant concentration of 40 nmol/L for 10 min induced a transient down-regulation of AR protein. Pretreatment with transcription inhibitor actinomycin D and translation inhibitor cycloheximide repressed cytoplasmic AR protein leves to 46% and 12% (means) of the androgen treatment control level respectively. Furthermore, androgen up-regulation of intracellular AR protein was partially inhibited (50%) by nonsteroidal androgen antagonist, flutamide. CONCLUSION: Homologous up-regulation of AR protein expression exist in synchronized VSMC, and the auto-regulation is time and testosterone dose dependent, accompanied by nuclear translocation of AR protein, and requires functional AR protein. In addition, our present data suggest that testosterone increases AR protein expression in VSMC at the level of both transcription and translation.

Androgens↗

PubMed2004

Apoptosis of human carcinoma cells in the presence of inhibitors of glycosphingolipid biosynthesis: I. Treatment of Colo-205 and SKBR3 cells with isomers of PDMP and PPMP.

Apoptosis, or programmed cell death, plays an important role in many physiological and diseased conditions. Induction of apoptosis in cancer cells by anti-cancer drugs and biosynthetic inhibitors of cells surface glycolipids in the human colon carcinoma cells (Colo-205) are of interest in recent years. In our present studies, we have employed different stereoisomers of PPMP and PDMP (inhibit GlcT-glycosyltransferase (GlcT-GLT)) to initiate apoptosis in Colo-205 cells grown in culture in the presence of (3)H-TdR and (3)H/or (14)C-L-Serine. Our analysis showed that the above reagents (between 1 to 20 microM) initiated apoptosis with induction of Caspase-3 activities and phenotypic morphological changes in a dose-dependent manner. We have observed an increase of radioactive ceramide formation in the presence of a low concentration (1-4 microM) of these reagents in these cell lines. However, high concentrations (4-20 microM) inhibited incorporation of radioactive serine in the higher glycolipids. Colo-205 cells were treated with L-threo-PPMP (0-20 microM) and activities of different GSL: GLTs were estimated in total Golgi-pellets. The cells contained high activity of GalT-4 (UDP-Gal: LcOse3Cer beta 1-4galactosyltransferase), whereas negligible activity of GalT-3 (UDP-Gal: GM2 beta 1-3galactosyltransferase) or GM2-synthase activity of the ganglioside pathway was detected. Previously, GLTs involved in the biosynthetic pathway of SA-Le(x) formation had been detected in these colon carcinoma (or Colo-205) cells (Basu M et al. Glycobiology 1, 527-35 (1991)). However, during progression of apoptosis in Colo-205 cells with increasing concentrations of L-PPMP, the GalT-4 activity was decreased significantly. These changes in the specific activity of GalT-4 in the total Golgi-membranes could be the resultant of decreased gene expression of the enzyme.

Antineoplastic Agents↗

PubMed2004

Apoptosis of human breast carcinoma cells in the presence of disialosyl gangliosides: II. Treatment of SKBR3 cells with GD3 and GD1b gangliosides.

Apoptosis, or programmed cell death, plays an important role in many physiological and diseased conditions. Induction of apoptosis in cancer cells has been monitored during the cells' progression to apoptosis by anti-cancer drugs and inhibitors of the cell surface glycolipids, gangliosides and SA-Le(x) biosyntheses [Basu, S (1991) Glycobiology, 1, 469-475; and ibid, 427-435] in animal tissues and human carcinoma cells, respectively. Induction of apoptosis in cancer cells by cell surface glycolipids in the human breast cancer (SKBR3) cells is the aim in this study. We have employed the disialosyl gangliosides (GD3 and GD1b) to initiate apoptosis in SKBR3 cells grown in culture in the presence of (14)C-L-Serine. At lower concentrations (0-20 microM) of exogenously added non-radioactive GD3, GD1b, or bovine ganglioside mixture (GM1:GD1a:GD1b:GT1a 2:4:4:2), the incorporation of radioactivity in both (14)C-sphingolipid and (14)C-ceramide was higher. However, at higher concentrations (20-100 microM), wherein apoptosis occurred in high frequency, the (14)C-incorporation decreased in both GSLs and ceramide. Apoptosis induction was monitored by the concomitant appearance of caspase-3 activation and the binding of a fluorescent dye PSS-380 to the outer leaflet of phosphatidyl-serine. These results indicated that, in addition to many unknown cell surface glycoconjugates GD3 or GD1b (disialosyl ganglioside) could play an important role in the regulation of breast carcinoma cell death.

Animals↗

PubMed2004

Apoptosis of human carcinoma cells in the presence of potential anti-cancer drugs: III. Treatment of Colo-205 and SKBR3 cells with: cis -platin, Tamoxifen, Melphalan, Betulinic acid, L-PDMP, L-PPMP, and GD3 ganglioside.

Breast cancer is the most common type of cancer, predominantly among women over 20, whereas colo-rectal cancer occurs in both men and women over the age of 50. Chemotherapy of both cancers affect rapidly growing normal as well as cancer cells. Cancer cells are non-apoptotic. Seven anti-cancer agents (cis -platin, Tamoxifen, Melphalan, Betulinic acid, D-PDMP, L-PPMP, and GD3) have been tested with human breast (SKBR3) and colon (Colo-205) carcinoma cells for their apoptotic effect and found to be positive by several assay systems. Colo-205 cells were obtained from ATCC, and the SKBR3 cells were a gift from the Cleveland Clinic. All of these six agents killed those two cell lines in a dose-dependent manner. In the early apoptotic stage (6 h), these cells showed only a flopping of phosphatidylserine on the outer lamella of the plasma membranes as evidenced by the binding of a novel fluorescent dye PSS-380. After 24 h of the treatment, those apoptotic cells showed damage of the plasma as well as the nuclear membrane as evidenced by binding of propidium iodide to the nuclear DNA. DNA laddering assay viewed further breakdown of DNA by 1% agarose gel electrophoresis analysis. It is concluded that during apoptosis the signaling by Mitochondrial Signaling Pathway (MSP) is stimulated by some of these agents. Caspase 3 was activated with the concomitant appearance of its p17 polypeptide as viewed by Westernblot analyses. Incorporation of radioactivity from [U-(14)C]-L-serine in total sphingolipid mixture was observed between 2 and 4 micromolar concentrations of most of the agents except ci s-platin. However, apoptosis in carcinoma cells in the presence of cis -platin is induced by a caspase 3 activation pathway without any increase in synthesis of ceramide.

Antineoplastic Agents↗

PubMed2004

Phylogenetic relationships among genotypes of worldwide collection of spring and winter ryes (Secale cereale L.) determined by RAPD-PCR markers.

Genetic similarities among 20 spring and 22 winter accessions of agronomically different ryes from fourteen countries were estimated by employing random amplified polymorphic DNA (RAPD) techniques. Cluster analysis of genetic distance data showed that 42 genotypes were readily classifiable into two main groups: spring and winter groups. Within the spring group, cultivars fell into a North European and an American-Chinese group. Cultivars of winter rye fell into four groups: Northern European, Russian, American and Chinese lines. A UPGMA-dendrogram based on genetic distances of cultivars of rye within the winter and spring groups showed that the clusters corresponded well to their geographical locations. The results indicated that isolation has played an important role in the evolution of rye, and that temporal isolation has influenced the genetic diversity of rye more than geographical isolation. In this experiment, RAPD proved to be a rapid, reliable and practicable method of revealing polymorphisms in rye populations.

Ecosystem↗

PubMed2004

[Role of leptin in development of peripubertal boys].

OBJECTIVES: To study the role of leptin in the development boys during their puberty and its relationship with insulin (INS), growth hormone (GH), estradiol (E2) and testosterone (T). METHODS: One hundred and fifty boys with simple obese aged 7 to 17 years, 150 normal healthy boys and 150 boys with malnutrition matched for age (+/- 3 months) and height (+/- 2 cm) were selected. Serum levels of leptin, INS, GH, E2 and T were measured for them. RESULTS: Serum level of leptin in obese group was significantly higher than that in normal group, and that in normal group was significantly higher than that in malnourished group. In the all three groups, serum level of leptin increased with age first until peak value, then began to decrease, with peak value of 6.96 microg/L at ages of 10-11 y in obese group, 10.25 microg/L at ages of 11-12 y in normal group and 5.08 microg/L at ages of 11-12 y in malnourished group. Serum level of leptin increased steadily from Tanner stages G1 to G2, then began to decrease steadily in G2 to G4. Serum level of leptin increased again in stage G5. Serum level of INS in boys increased steadily with age from 7 to 17 years old. Serum levels of GH, T and E2 in boys began to increase since 10-11 years old. Serum level of leptin positively correlated with serum level of INS and negatively correlated with serum levels of GH and T, but not correlated with serum level of E2. CONCLUSIONS: Leptin may promote pubertal development of boys, but not the determinant factor in triggering and maintaining their pubertal development. Re-increase in level of leptin during stage G5 could inhibit secretion of GH, and signalize the end of puberty in boys.

Adolescent↗

PubMed2003

[A comparative study of root smear layer removal using different pH EDTA salts].

OBJECTIVE: To evaluate the effect of different pH EDTA salts on removing root canal smear layers. METHODS: Sixty human teeth with single root were instrumented using step-back technique, then were irrigated with several irrigating solutions including A: 0.9% saline; B: 5.25% NaOCl +3% H2O2; C: 15% EDTA (pH = 6.5); D: 15% EDTA (pH = 13); E: 15% EDTA (pH = 6.5) 25% NaOCl +3% H2O2; F: 15% EDTA (pH = 13) 25% NaOCl +3% H2O2. After the teeth were split, the root canal walls were examined with scanning electron microscopy at the coronal, middle and apical thirds for smear layer removal. RESULTS: Except A and B group, all the groups were effective on removing smear layer at the coronal, middle thirds of the root canal, group C had a stronger effect to remove smear layer than group D (P < 0.05), group E was the most effective among these groups. However, these groups were all ineffective on removing smear layer at the apical thirds of root canal. CONCLUSIONS: 15% EDTA (pH = 6.5) 25% NaOCl +3% H2O2 was the most effective irrigation on removing smear layer.

Edetic Acid↗

PubMed2002

Requirement of mitogen-activated protein kinase kinase 3 (MKK3) for activation of p38alpha and p38delta MAPK isoforms by TGF-beta 1 in murine mesangial cells.

Transforming growth factor-beta1 (TGF-beta1) is a potent inducer of extracellular matrix (ECM) synthesis that leads to renal fibrosis. Intracellular signaling mechanisms involved in this process remain incompletely understood. Mitogen-activated protein kinase (MAPK) is a major stress signal-transducing pathway, and we have previously reported activation of p38 MAPK by TGF-beta1 in rat mesangial cells and its role in the stimulation of pro-alpha1(I) collagen. In this study, we further investigated the mechanism of p38 MAPK activation by TGF-beta1 and the role of MKK3, an upstream MAPK kinase of p38 MAPK, by examining the effect of targeted disruption of the Mkk3 gene. We first isolated glomerular mesangial cells from MKK3-null (Mkk3-/-) and wild-type (Mkk3+/+) control mice. Treatment with TGF-beta1 induced rapid phosphorylation of MKK3 as well as p38 MAPK within 15 min in cultured wild-type (Mkk3+/+) mouse mesangial cells. In contrast, TGF-beta1 failed to induce phosphorylation of either MKK3 or p38 MAPK in MKK3-deficient (Mkk3-/-) mouse mesangial cells, indicating that MKK3 is required for TGF-beta1-induced p38 MAPK activation. TGF-beta1 selectively activated the p38 MAPK isoforms p38alpha and p38delta in wild-type (Mkk3+/+) mesangial cells, but not in MKK3-deficient (Mkk3-/-) mesangial cells. Thus, activation of p38alpha and p38delta is dependent on the activation of upstream MKK3 by TGF-beta1. Furthermore, MKK3 deficiency resulted in a selective disruption of TGF-beta1-stimulated up-regulation of pro-alpha1(I) collagen expression but not TGF-beta1 induction of fibronectin and PAI-1. These data demonstrate that the MKK3 is a critical component of the TGF-beta1 signaling pathway, and its activation is required for subsequent p38alpha and p38delta MAPK activation and collagen stimulation by TGF-beta1.

Activating Transcription Factor 2↗

PubMed2002

[The role of dead bacteria in streptococcus sanguis biofilm reformation].

OBJECTIVE: To investigate the role of dead bacteria in Streptococcus sanguis biofilm reformation. METHODS: Vital fluorescent staining technique and Confocal laser Scanning Microscopy (CLSM) were combined to observe Streptococcus sanguis biofilm on the saliva-coated glass (SCG) in an artificial mouth model, the thickness and bacterial density were compared between biofilm reformed on saliva covered slide with dead cells (test group) and biofilm reformed on saliva coated slide without dead cells (control group) at different times. RESULTS: At 30 min, the bacterial density rather than biofilm thickness of test group was significantly higher than that of control group (P<0.05), whereas at 60 min, 120min, 240min, the biofilms were significantly thicker in test group than that (P<0.05). CONCLUSION: The dead cells may help biofilm reformation during the formation of biofilm.

English Abstract↗