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Biomedical subjects

S Zheng

Publications and source records attributed to S Zheng.

At least 109 records · Page 6Linked to original sources
PubMed1999

Wnt signaling induces GLT-1 expression in rat C6 glioma cells.

The regulation of glial and neuronal Na+-dependent glutamate/aspartate transporters is of interest because abnormal glutamate transport may be responsible for certain neurological diseases. Because expression of the Wnt-1 protooncogene results in induction of the glial-type glutamate transporter GLAST in PC12 neuron-like cells, we have evaluated the effect of Wnt-1-induced signaling on glutamate transporter expression in rat C6 glioma cells. C6 cells are known normally to express EAAC1, a neuronal glutamate transporter, but not the GLAST or the GLT-1 glutamate transporter. C6 cells that ectopically expressed Wnt-1 contained a GLT-1 RNA species similar in size (>10 kb) to the GLT-1 transcript present in rat brain, and they also contained a previously unreported 3.3-kb GLT-1 RNA species. Both GLT-1 RNAs contain large parts of the coding region. However, the 3.3-kb GLT-1 species contains at least one small deletion within the coding region. The Wnt-1-expressing C6 cells contained little, if any, GLT-1 protein as determined by immunological techniques. We suggest that one or both of the GLT-1 RNA species induced by Wnt-1 either fail to be translated or yield abnormal translation products that are quickly degraded. Wnt-1-expressing C6 cells may thus represent a novel in vitro system for studying GLT-1 transporter expression at the transcriptional and/or posttranscriptional levels.

ATP-Binding Cassette Transporters↗
PubMed1999

Subcellular distribution and tissue expression of phospholipase Dalpha, Dbeta, and Dgamma in Arabidopsis.

Three phospholipase Ds (PLDs; EC 3.1.4.4) have been cloned from Arabidopsis, and they exhibit two distinct types of activities: polyphosphoinositide-requiring PLDbeta and PLDgamma, and polyphosphoinositide-independent PLDalpha. In subcellular fractions of Arabidopsis leaves, PLDalpha and PLDgamma were both present in the plasma membrane, intracellular membranes, mitochondria, and clathrin-coated vesicles, but their relative levels differed in these fractions. In addition, PLDgamma was detected in the nuclear fraction. In contrast, PLDbeta was not detectable in any of the subcellular fractions. PLDalpha activity was higher in the metabolically more active organs such as flowers, siliques, and roots than in dry seeds and mature leaves, whereas the polyphosphoinositide-dependent PLD activity was greater in older, senescing leaves than in other organs. PLDbeta mRNA accumulated at a lower level than the PLDalpha and PLDgamma transcripts in most organs, and the expression pattern of the PLDbeta mRNA also differed from that of PLDalpha and PLDgamma in different organs. Collectively, these data demonstrated that PLDalpha, PLDbeta, and PLDgamma have different patterns of subcellular distribution and tissue expression in Arabidopsis. The present study also provides evidence for the presence of an additional PLD that is structurally more closely related to PLDgamma than to the other two PLDs.

Arabidopsis↗
PubMed1999

Aberrant methylation of p16INK4a in anatomic and gender-specific subtypes of sporadic colorectal cancer.

Colorectal cancer (CRC) occurring in the proximal colon and among women may represent a distinct subtype of the disease. In the present study of 120 sporadic CRCs, we used methylation-specific PCR to test whether methylation of the CpG island in the 5' region of the p16INK4a tumor suppressor gene was associated with anatomical location, gender, or other clinicopathological characteristics. Overall, 18.3% of the tumors had detectable p16INK4a methylation. A marked preponderance of methylated tumors occurred within the proximal colon; cancers occurring proximal to the sigmoid colon were 13.1 times more likely to contain methylated p16INK4a compared with distal tumors. In addition, female patients were 8.8 times more likely than males to have methylation-positive cancers, and p16INK4a methylation was also associated with poorly differentiated tumors. The localization of tumors with p16INK4a methylation within the proximal colon and among female patients specifically adds to a growing database of molecular alterations that define important subtypes of sporadic CRC. The potentially reversible nature of CpG methylation may provide novel therapeutic opportunities for this increasing subtype of the disease, which, due to anatomical location, presents a great challenge for early detection.

Aged↗
PubMed1999

[Effect of conjugated estrogen and Org OD14 on serum lipoprotein and apolipoprotein in perimenopausal and postmenopausal women].

OBJECTIVE: To determine the effect of conjugated estrogen and Org OD14 on serum lipoprotein and apolipoprotein in perimenopausal women. METHOD: 74 patients were divided into 2 groups: 46 were given conjugated estrogen 0.625 mg and medroxyprogesterone acetate 4 mg daily according to the continuous sequential, regimen 28 were given Org OD14 2.5 mg every two days. Serum lipoprotein and apolipoprotein estradiol and follicle stimulating hormone were measured before and (one and two years) after treatment. RESULTS: Total Cholesterol (TC), Triglycerin (TG), high density lipoprotein (HDL-C), Apolipoprotein AI (Apo AI), Apolipoprotein AII (Apo AII), Apolipoprotein B(Apo B), Apolipoprotein CII(Apo CII), Apolipoprotein CIII(Apo CIII), Lipoprotein(a)[Lp(a)] increased significantly (P < 0.05), while ApoB/AI, ApoCII/CIII decreased significantly(P < 0.05) in conjugated estrogen group. ApoCIII, E decreased, while ApoAI/AII increased significantly (P < 0.05) in Org OD14 group. After two years treatment, TC, HDL-C, ApoAI, ApoCIII, ApoE, TC, HDL-C, ApoAI, ApoCIII, ApoE of conjugated estrogen group were higher than those of Org OD14 group(P < 0.05), ApoCII/CIII of Conjugated estrogen was lower than that of Org OD14 group(P < 0.05). CONCLUSION: Postmenopausal hormone replacement therapy regulates the constitution of serum lipoprotein and apolipoprotein.

Adult↗
PubMed1999

Regulatory roles of IL-12, IL-4 and IFN-gamma on IgE synthesis in atopic patients.

OBJECTIVE: To investigate the mechanism of cytokine regulation in atopy by analyzing the effects of three major cytokines, IL-4, IL-12 and IFN-gamma on in vitro IgE synthesis of human peripheral blood mononuclear cell (PBMC) from normal individuals and atopic patients. METHODS: We investigated 5 normal individuals and 22 atopic patients including 12 allergic asthma, 8 allergic rhinitis and 2 atopic dermatitis. Human PBMCs were separated and incubated in 96-wells culture plates with different cytokines. Cultured for 7 days, the supernatant was collected and the contents of IgE synthesized in vitro were detected. RESULTS: There was no IgE synthesis in vitro of PBMC from all the normal individuals and 7 patients, however, other 15 patients' PBMC could produce IgE in vitro. We found that rhIL-4 could induce in vitro IgE synthesis of PBMC from all the normal individuals and 22 patients. rhIL-12 could inhibit IgE synthesis induced by rhIL-4. Further investigation of cytokine effects on IgE synthesis was conducted in 15 patients whose PBMCs did produce IgE in vitro (average level was 714 +/- 1105 ng/L). The following effects were observed: (1) 10 micrograms/L rhIL-4 could augment in vitro IgE synthesis from 714 +/- 1105 ng/L to higher level of 1483 +/- 1396 ng/L; (2) 20 micrograms/L rhIL-12 could inhibit in vitro IgE synthesis from 714 +/- 1105 ng/L to lower level of 452 +/- 969 ng/L; (3) rhIL-12 could block IgE synthesis induced by rhIL-4 to the level of 583 +/- 1084 ng/L; (4) 50 micrograms/L IFN-gamma could inhibit in vitro IgE synthesis from 714 +/- 1105 ng/L to the level of 461 +/- 1063 ng/L. CONCLUSIONS: rhIL-4 could induce in vitro IgE synthesis, rhIFN-gamma could inhibit the in vitro IgE synthesis and rhIL-12 could antagonize rhIL-4 effect on in vitro IgE synthesis of PBMC from atopic patients.

Adult↗
PubMed1999

[Mutations of hMLH1 and hMSH2 genes in suspected hereditary nonpolyposis colorectal cancer].

OBJECTIVE: To analyze the molecular characteristics of 29 ICG-HNPCC families and 34 suspected HNPCC families. METHODS: Genomic DNAs were prepared from peripheral blood samples of probands for DNA test. PCR-SSCP and DNA sequencing analysis were employed to screen the germline mutations of hMLH1 and hMSH2 genes. RESULTS: In 29 ICG-HNPCC families, 9 mutations in the hMLH1 gene were detected, while no mutation was found in the hMSH2 gene. The total mutation rate was 31.0% (9/29). In 34 suspected HNPCC families, 8 mutations in the hMLH1 gene and 2 mutations in the hMSH2 gene were detected. The total mutation rate in this group was 29.4% (10/34), including hMLH1 gene 23.5% (8/34) and hMSH2 gene 5.9% (2/34). hMLH1 gene was proven to be the main responsible gene in both ICG-HNPCC and suspected HNPCC families, and no obvious difference was found between the mutation rate in the two kinds of families (P > 0.05). As for the mutation type and location, similar characteristics were also detected. Almost all mutations located in the latter half of both genes, and mutation leading to protein truncation was the commonest type. CONCLUSION: The similarity of mutation rate, mutation type and mutation location between ICG-HNPCC and suspected HNPCC suggested the similarity of molecular basis and genetic background between these two groups, and also strongly indicated our criteria for suspected HNPCC is reasonable, and useful in the clinical diagnosis and management of HNPCC.

Adaptor Proteins, Signal Transducing↗
PubMed1999

[Gene detection and localization by FISH with short DNA fragment cloned in plasmid].

OBJECTIVE: To establish a method of detecting and localizing newly cloned gene by FISH using short DNA fragment. METHODS: Bio-14-dATP was incorporated into the target gene cloned in plasmid by nick translation followed by conventional FISH with some modification. By Means of this method, c-met, c-erbB2, 1A6, APC and Rb genes were examined in ovarian and gastric cancer cell lines. RESULTS: 1A6, a newly isolated gene was located at the long arm of one of the C group chromosomes. Oncogene c-met, c-erbB2 and trmor suppressor gene APC, Rb were shown to produce clear-cut hybridization signals in ovarian and gastric cancer cells. CONCLUSION: Short DNA fragment cloned in plasmid is useful for studies of gene localization, gene deletion and amplification by FISH.

Chromosome Mapping↗
PubMed1999

[Study of APC, Rb, c-met gene copy numbers of human gastric mucosa epithelial cell line GES-1].

OBJECTIVE: To study the copy number of oncogene/tumor suppressor genes in GES-1 cell line to identify its characteristics. METHODS: Bio-14-dATP was incorporated into APC, Rb, c-met gene cloned in plasmid by nick translation. Fluorescence in situ hybridization (FISH) of interphase nuclei of GES-1 cells was performed. RESULTS: Two copies of APC were shown in 48% interphase nuclei and 3 copies in 22%; 71% and 80% cells had normal copies of Rb and c-met genes in their nuclei, respectively. CONCLUSION: GES-1 cell line is a relatively normal gastric mucosa epithelial cell line and can be used as a human in vitro model system for the study of carcinogenesis.

Cell Line↗
PubMed1999

[The value of "occult blood bead" in detection of upper digestive tract disorders with bleeding].

OBJECTIVE: To evaluate the usefulness of "occult blood bead" (OBB) test in the screening of gastric and esophageal cancers. METHODS: In the study, subjects with upper gastro-intestinal (GI) symptoms received gastric OBB test before gastroscopic examination. OBB test was scored as +(-)+++ according to the intensity of reactions. The sensitivity, specificity, and likelihood ratio of OBB test were evaluated according to results of gastroscopic and/or pathological examination. RESULTS: Among 5,217 subjects, 2,403 showed positive OBB test (46.1%). In this series, 202 cases of malignant disorders were detected (gastric cancer in 155 and esophageal cancer in 47). There were 69 cancer cases among 1847 subjects presenting "+" OBB test, with a cancer detection rate of 3.7%. In 393 subjects presenting "++" OBB test, 28 were cancer (7.1%); while in 163 subjects presenting "+++" OBB test, 34 were diagnosed as gastric or esophageal cancer with a detection rate of 20.9%. The sensitivity of OBB test in detection of gastric and esophageal cancer was 0.65, the specificity was 0.55, likelihood ratio was 1.43 and the Youden Index was 0.2. CONCLUSION: OBB test provides a new, simple and non-invasive method for detection of upper digestive tract bleeding. For detection of upper GI carcinomas it presents a reasonable sensitivity and specificity in a group of subjects with upper GI symptoms. OBB test can be used as a prelimnary screening tool for gastric and esophageal cancer in asymptomatic general population.

Adolescent↗
PubMed1999

[Study of microsatellite instability of colotectal cancer and its clinical significance].

OBJECTIVE: To evaluate microsatellite instability (MI) of colorectal cancer in China. METHOD: Replication error (RER) status was examined by using 6 microsatellite loci D2S123, D2S119, D13S160, D8S282, D3S1293 and D18S58. The loci were amplified by PCR technique. The PCR products were separated on denatured polyacrylamide gel and then silver stained. RESULTS: Of the 60 cases of colorectal cancer studied, 20 (33.3%) showed MI, 11 cases (18.3%) were RER positive. In 11 RER-positive cases, 4(36.4%) had family history of malignant tumor, while only 8.2% had positive family history in RER-negative cases (P < 0.05). The RER-positive patients were younger, and their cancer occurred more frequently in the colon with invasive type of growth. There were more cancers in Dukes III and IV in the REF-positive patients. In 5 colorectal cancer cases associated with adenoma, MI was detectable in 4 adenomas. CONCLUSION: MI phenotype might be present ubiquitously in sporadic colorectal cancers in China. Its frequency is comparable to that of other reports. MI is a relatively early molecular event in the genesis of colorectal cancers. RER is a useful sign of susceptibility to the development of colorectal cancer.

Adult↗
PubMed1999

[Mutation of human mismatch repair genes in hereditary nonpolyposis colorectal cancer (HNPCC) families].

OBJECTIVE: To investigate germline mutations of mismatch repair genes hMLH1 and hMSH2 in 29 HNPCC families. METHODS: Mutations were detected by PCR-SSCP analysis, and confirmed by DNA sequencing. RESULTS: (1) In 29 families, the overall mutation rate of these two genes was 31.0% (9/29). Mutation detected in all of the 9 families was located in the hMLH1 gene, indicating that the hMLH1 gene was the main responsible gene in these families. An obvious difference was observed when compared to the mutation rate in the control group (P < 0.01); (2) All of the 10 family members who developed colorectal cancer (CRC) harbored the same mutation as detected in their proband, indicating a strong association between gene mutation and development of CRC. In 29 healthy family members, 5 asymptomatic carriers of mutation were found who were considered as the high-risk populations of CRC. CONCLUSION: A certain number of HNPCC families can be benefited from the genetic screening for mutation of the mismatch repair genes.

Adaptor Proteins, Signal Transducing↗
PubMed1999

[Experimental study of yishou tiaozhi tablet on free radical metabolism in aging model mice].

OBJECTIVE: To observe the effect of Yishou Tiaozhi tablet (YSTZT) on the metabolism of free radical in mice of aging model. METHODS: Using the aging model induced by hypodermic injection of 5% D-Galactose in mice for forty days. The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in serum, activity of monoamine oxidase B (MAO-B), Na(+)-K(+)-ATPase in brain were investigated after the treatment. RESULTS: In comparing to the aging model group, it showed that YSTZT could obviously inhibit the increase of level of MDA in serum and the activities of MAO-B in brain; and enhance the activities of SOD, GSH-Px in serum, and the activities of Na(+)-K(+)-ATPase in brain. Furthermore, YSTZT could obviously elevate the tolerance to fatigue and hypoxia in mice. CONCLUSIONS: YSTZT can effectively improve the free radical metabolism of senile body, it is an ideal and effective medicine in preventing aging, which is also one of the experimental basis in proving the theory of "Spleen and Kidney deficiency complicated with stasis and phlegm cause aging".

Animals↗
PubMed1999

[Atypical pheochromocytoma].

OBJECTIVE: To improve the diagnosis and treatment of atypical pheochromocytoma. METHODS: 51 cases of pheochromocytoma were treated from July 1985 to August 1998. RESULTS: Of the 51 cases, 19 were atypical, and were characterized by silent tumor, pheochromocytoma in pregnancy, bilateral tumor, extraadrenal tumor, malignant tumor, and recurrent tumor. Open operation was performed for all kinds of cases in accordance with their special characteristics. CONCLUSIONS: Surgical extirpation is the only means for the treatment of atypical pheochromocytoma and meticulous perioperative management is essential.

Adrenal Gland Neoplasms↗
PubMed1999

[Lutembacher's syndrome].

OBJECTIVE: To compare classical and acquired Lutembacher's syndrome (mitral restenosis after percutaneous balloon mitral valvuloplasty) in attempt to know their different in pathophysiology, diagnosis, and surgical treatment. METHODS: The data from 22 cases of classical and acquired Lutembacher's syndrome who underwent surgical treatment in the same period were analyzed. RESULTS: No death occurred in the classical group. In the acquired group the mortality however was 42.8% for those highly complicated with pulmonary hypertension and right heart failure. CONCLUSIONS: Classical Lutembacher's syndrome can be corrected satisfactorily. The acquired one deteriorates rapidly with severe pulmonary hypertension and right heart failure, and needs early surgical intervention reduce the operation mortality.

Adult↗
PubMed1999

[Studies on appropriate methods for dust scrubbing from dust-laden gas in shaft kilns of small-sized cement plants].

OBJECTIVE: To study an appropriate method for dust scrubbing from dust-laden gas in the shaft kilns of small-sized cement plants. METHODS: Characteristics of dust-laden gas, including its temperature, dew point, dust concentration, diameters of dust particles and their distribution, as well as fractional dust collection efficiencies of the dust precipitator settling chamber, cyclone, impinging scrubber, impinging-spray scrubber, were measured according to the National Standards for Measurement of Particulate in Exhaust Gas Emitted from the Stationary Pollution Sources and Sampling Methods of Gaseous Pollutants (GB/T16157 - 1996), with a WY-1 In-stack 7-Stage Cascade Impactor for fractional dust collection. RESULTS: The fractional dust collection efficiency of the settling chamber for the particles greater than 12 microm was 72%, while that of the cyclone for the particles of 2 microm, 5 microm and 10 microm were 40.0%, 72.5% and 88.9%, respectively, and that of impinging scrubber was 55.0%, 91.0% and 98.9%, respectively; and that of impinging-spray scrubber were 96.0%, 99.2% and 99.6%, respectively. Results showed that 81% of the dust (by weight) from the shaft kilns were greater than 10 microm, so the settling chamber was effective for the removal of this fraction of dust. But dust particles behind the settling chamber were finer, and about 59% - 69% of them were less than 2 microm in diameters. In that case, the cyclone, impinging scrubber and impinging-spray scrubber could give an overall collection efficiency of 54%, 57% and 96%, respectively. Based on this, the following combination of dust collectors were adopted to meet the national standards for exhaust emission: a settling chamber plus an electrostatic precipitator, a settling chamber plus an impinging-spray scrubber and a settling chamber plus an impinging scrubber. The cement plants could select appropriate dust collectors according to their technical and economical conditions. CONCLUSION: Based on the results of the studies, appropriate dust collectors used to treat dust-laden gas from shaft kilns to meet the national standards for exhaust emission were recommended.

Air Pollutants, Occupational↗
PubMed1999

[Analysis on chemical composition of genus Pueraria stems from China].

OBJECTIVE: To provide scientific basis for developing and utilizing Pueraria stems. METHOD: The contents of total flavonoid were determined by means of UV spectrophotometry. The isoflavones in stems and roots of nine species of genus Pueraria were analyzed by TLC. RESULTS: The stems and roots are similar in chemical composition. CONCLUSION: Pueraria stems as a potential resource could be used as a substitute for Pueraria roots.

Chromatography, Thin Layer↗
PubMed1999

[Gas-sensing transmittivity spectrum of two-dimension SnO2: TiO2 compound film in ammonia vapor].

In this paper, we studied the gas-sensing transmittivity spectrum of the two-dimension SnO2: TiO2 compound film in ammonia vapor. It was observed that when the gas concentration was relatively low the transmittivity decreased as the gas concentration decreased, and when the gas concentration was relatively high, the transmittivity increased as the gas concentration increased. We considered the effect of the wet vapor, and explained this phenomenon.

English Abstract↗