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Biomedical subjects

C Sun

Publications and source records attributed to C Sun.

At least 73 records · Page 4Linked to original sources
PubMed2000

Formation and characterization of phosphatidylethanolamine/lysophosphatidylcholine mixed vesicles.

The lipid aggregates formed by adding lysophosphatidylcholine (lysoPC) solution to phosphatidylethanolamine (PE) dispersion at 4 degrees C followed by incubating it at 37 degrees C were proved to be a vesicle system judged from the negatively stained electron micrographs and the latency of calcein fluorescence. The results obtained are analogous to those described for phosphatidylcholine (PC) vesicles. The chromatography results showed that the incorporation of PE and lysoPC into the PE/lysoPC vesicles was in a molar ratio of 5 to 2. The PE/lysoPC membrane was found to have similar barrier potentials for Cl- or calcein efflux to the PC membrane. 1H Nuclear magnetic resonance measurement suggested that lysoPC dominated the external monolayer of the vesicles. Furthermore, it was found that PE/lysoPC vesicles and micelles could coexist when a large amount of lysoPC was added to the PE/lysoPC vesicle suspension. The formation of PE/lysoPC vesicles is discussed in combination with the inhibition of interlayer attachment by lysoPC from the PE membrane.

Chromatography, Gel↗
PubMed2000

Characterization and transcriptional profiles of two rice MADS-box genes.

The plant MADS-box gene family plays a key role in plant development, especially in flower development. We designed degenerate primer according to the MADS-box conserved region and isolated two cDNA from rice, FDRMADS6 and FDRMADS7, which are homologous to AP1. RT-PCR expression analyses by using total RNA isolated from root, shoot and flower showed that the FDRMADS6 transcript was detectable only in flower while FDRMADS7 was expressed in all three tissues. In situ hybridization experiments indicated that at the early stage of rice flower development, the transcripts of FDRMADS6 and FDRMADS7 were detected in the spikelet apical meristem, which were same as AP1. At the late stage, when flower organ primordia started differentiating, the expression of FDRMADS6 appeared to be specifically localized in developing stamens and the pistil primordia, while the transcripts of FDRMADS7 were detectable abundantly throughout the organ primordia. Our results suggest the two MADS-box genes may be members of the AP1 family, but may have different functions.

Journal Article↗
PubMed2000

Interstitial deletion of 11q13 sequences in HeLa cells.

Previous cytogenetic and molecular genetic studies have shown that the HeLa (cervical carcinoma) cell line D98/AH-2 contains two apparently normal copies of chromosome 11 and additional 11q13-25 material translocated onto a chromosome 3 marker. To determine the 11q13 breakpoint, we performed fluorescence in situ hybridization (FISH) using 18 different 11q13 specific BAC (bacterial artificial chromosome) and cosmid probes spanning a 5.6 Mb interval. Markers localized to the multiple endocrine neoplasia type 1 (MEN1) gene (menin) were also included in the analysis. The FISH study identified an interstitial deletion between markers D11S449 and GSTP1, an interval of 2.3 Mb, in the marker chromosome. This deletion did not include the MEN1 gene. Because point mutations and methylations can inactivate the MEN1 gene, single stranded conformational polymorphism (SSCP) and Northern and Western blot analyses were performed with MEN1 specific probes and antibody. SSCP did not reveal mutations of the MEN1 gene in HeLa or in seven other cervical cancer cell lines. Northern and Western blot studies revealed normal levels of expression of this gene in the cervical cancer cell lines as well as in HeLa cell derived tumorigenic hybrids. Because deletions of tumor suppressor genes often occur in cancer progression, we hypothesize that the inactivation of a tumor suppressor gene other than MEN1, localized to the 2.3 Mb interval on 11q13, might play a role in the abnormal growth behavior of HeLa cells in vitro or in vivo.

Cell Transformation, Neoplastic↗
PubMed2000

Polychlorinated organic compounds in Yangtse River sediments.

Polychlorinated organic compounds (PCOCs) were analyzed in Yangtse River sediments. The results show that the concentrations of PCOCs in Yangtse River sediments followed the order of DDTs > HCB > HCHs > PCBs. High PCOCs concentrations were detected in sediments from station Y02a and Y02b, which are located in the main input of the Yangtse River (Nanjing section). Results also show that the PCOCs values were highly correlated with organic carbon content and heavy metal contamination.

China↗
PubMed2000

The Nrf2 transcription factor contributes both to the basal expression of glutathione S-transferases in mouse liver and to their induction by the chemopreventive synthetic antioxidants, butylated hydroxyanisole and ethoxyquin.

An overview is provided of the cancer chemoprevention actions of phenolic antioxidants and 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (ethoxyquin). These agents principally appear to exert their beneficial effects through induction of phase II drug-metabolizing enzymes such as glutathione S-transferase (GST). The requirement for oxidative metabolism of the synthetic antioxidants to carbonyl-containing compounds, including quinones, in order that they can induce gene expression is discussed. Previous work has shown that the basic leucine zipper transcription factor Nrf2 is involved in induction of GST by the phenolic antioxidant butylated hydroxyanisole (BHA). Evidence is provided from a mouse possessing a targeted disruption of the Nrf2 gene that, in murine liver, the transcription factor regulates basal expression of several class Alpha and class Mu GST subunits, but not class Pi GST. In the Nrf2 knock-out mouse, hepatic induction of class Alpha and class Mu GST by BHA and the synthetic antioxidant ethoxyquin is similarly impaired, suggesting that these agents affect gene activation by a related mechanism. Significantly, residual induction of GST by antioxidants is apparent in the Nrf2 mutant mouse, indicating the existence of an alternative mechanism of gene activation.

Animals↗
PubMed2000

A gain-of-function phenotype conferred by over-expression of functional subunits of the COP9 signalosome in Arabidopsis.

The COP9 signalosome is a conserved cellular regulator present in diverse organisms. To understand the structural and functional relationship of the COP9 signalosome with its subunits, we expressed in wild-type and mutant Arabidopsis backgrounds two orthologues of subunit 1, rice FUS6 (rFUS6) and human GPS1, and Arabidopsis subunit 8 (COP9). In Arabidopsis, rFUS6 can functionally replace Arabidopsis endogenous FUS6 to form the COP9 signalosome complex and rescue the null fus6-1 mutant phenotype. Moreover, light-grown rFUS6 over-expression seedlings displayed longer hypocotyls and reduced anthocyanin accumulation in comparison to wild-type seedlings, which is opposite to the fus6/cop11 mutant phenotype. The long-hypocotyl phenotype was also observed in transgenic seedlings over-expressing Arabidopsis COP9. This finding indicates that over-expression of a functional subunit 1 or subunit 8 of the COP9 signalosome confers a gain-of-function phenotype relative to the complex. Human GPS1, when expressed in the fus6-1 null mutant of Arabidopsis, can assemble into a chimeric COP9 signalosome at low efficiency, demonstrating the structural conservation of the complexes between human and Arabidopsis. This low-abundancy chimeric complex is insufficient to fully rescue the mutant but is able to attenuate the mutant severity.

Amino Acid Sequence↗
PubMed2000

The influence of human intervertebral disc tissue on the metabolism of osteoblast-like cells.

Extensive studies have been performed to evaluate different factors that may affect on spinal interbody fusion, but the role of intervertebral disc tissue in the fusion process remains unclear. To study the influence of intervertebral disc tissue on osteoblast metabolism, we harvested disc tissue from patients who had undergone spinal surgery. The nucleus pulposus and annulus fibrosus were separately co-cultured with osteoblast-like cells SaOS-2 by means of culture inserts or organ culture. We assayed alkaline phosphoatase activity, 3H-thymidine incorporation into the DNA, and production of collagen type I, IL-1beta, IL-6, IL-10, and TNF-alpha. Exposure of the nucleus pulposus (NP) to osteoblast-like cells revealed stimulation of alkaline phosphatase production, 3H-thymidine incorporation and collagen type I production. Exposure of the annulus fibrosus (AF) stimulated 3H-thymidine incorporation and collagen type I production, but did not affect ALP activity. IL-6 was detected after application of NP and AF. Interleukin IL-10, IL-1beta and TNF-alpha were all below detection levels after application of disc tissue. Our findings show that frozen disc tissue stimulates the metabolism of osteoblast-like cells in vitro.

Adolescent↗
PubMed2000

Seeds induced to germinate rapidly by mentally projected 'qi energy' are apparently genetically altered.

Mentally controlled qi energy can induce crop seeds to sprout and root for several cm within about 20 min. The RAPD method was used to compare treated groups of wheat and pea seeds and their controls using 11 selected primers. Seven primers amplified polymorphisms in wheat seeds and 5 in pea seeds. It was thought preliminarily that qi energy changed the structure of a germination-correlated gene site speeding up expression and advancing it in time.

Germination↗
PubMed2000

Conditioned immunosuppressive effect of cyclophosphamide on delayed-type hypersensitivity response and a preliminary analysis of its mechanism.

In the present study, camphor odor and intraperitoneal (i.p.) injection of cyclophosphamide (CY) were used as conditioned stimulus (CS) and unconditioned stimulus (US), respectively. In the unconditioned group, mice were exposed to camphor odor for 1 h followed by an i.p. injection of CY (75 mg/kg). On the next day, the above CS/US association trial session was repeated followed by smearing dinitrochlorobenzene (DNCB) on mouse abdominal skin for sensitizing the animal for delayed-type hypersensitivity (DTH) response. Five days after DNCB sensitization, mice were exposed to camphor odor (1 h), followed by an i.p. injection of CY, and then DNCB was smeared on the left ear of mice for the challenge of DTH response. Both the left/right ear weight ratio and the activity of leukocyte migration inhibitory factor (LMIF) were used as the index of DTH response, which was done 24 h after DNCB challenge. In the conditioned group, the treatment was the same as that in the unconditioned group, except that normal saline was injected on day 5 instead of CY. Furthermore, in order to analyze the mechanism of the conditioned response (CR), the mouse serum from the conditioned group (CR serum) was injected into normal mice 6 h prior to DNCB challenge. Results showed that in the conditioned group, left/right ear weight ratio and LMIF activity were statistically lower than that in the DTH group, and there was no difference between conditioned and unconditioned groups. Thus, an animal model of conditioned immunosuppressive response had been established. The results also showed that after CR serum was injected into normal mice, DTH response was also significantly suppressed. However, if CR serum was treated with dialysis (10,000 molecular weight cut-off), the suppressive effect of CR serum on DTH response disappeared. Taken together, the data suggested that a chemical compound(s) in serum, with a molecular weight less than 10,000, was important in mediating the conditioned immunosuppressive response. This may be a very important molecule(s) that could be very critical to our understanding of the interaction between the central nervous system and immune function.

Animals↗
PubMed2000

[Improved liposome encapsulated hemoglobin by electret technology and its influence on the blood rheologic behavior in vitro].

To study the influence of different electret properties of Liposome Encapsulated Hemoglobin(LEH) on the blood rheologic behavior in vitro, four kinds of LEH have been prepared. Their electret properties have been determined by using Thermally Stimulated Depolarization Current(TSDC). The results show that 4# LEH, whose Ta is 12 degrees C and Ia is -5.6 x 10(-9) A, has the best electret property, furthermore, the results of the thrombus formation in vitro also show that the addition of 4# LEH induces the lightest thrombus figuration in vitro. It is obvious that the rational improvement of the electret property of LEH can meliorate the surface charge of blood and effectively inhibit the formation of thrombus.

Blood Viscosity↗
PubMed2000

[Is Gly460Trp variant of alpha-adducin associated with essential hypertension in the Hans of Chinese population].

OBJECTIVE: To determine whether the variant of adducin alpha subunit (alpha-adducin) is in association with essential hypertension in the Hans of Chinese population. METHODS: One hundred and eighty-three patients with essential hypertension and 129 normotensive subjects were included in this study. Genomic DNA was isolated from 3 ml of whole blood. Polymerase chain reaction, single-strand conformational polymorphism and DNA sequencing analysis techniques were used to detect the variant in the exon 10 of alpha-adducin gene. The clinical data of height, weight and blood pressure were also measured in all subjects. RESULTS: A G-->T substitution at nucleotide 614 in exon 10 of alpha-adducin gene which resulted in the Gly460Trp variant was found in the Hans. The distribution of Gly/Gly, Gly/Trp and Trp/Trp genotypes was coincident with Hardy-Weinberg equilibrium and there were no statistical differences in the three genotypes and Trp allele frequencies between hypertensive and normotensive subjects (P>0.05). The variant of alpha-adducin genotypes was not associated with any significant differences in age, body mass index and blood pressure. CONCLUSION: A G-->T substitution at nucleotide 614 in exon 10 of alpha-adducin gene is found, but there is lack of the association between the variant of alpha-adducin gene and essential hypertension in the Hans of Chinese population.

Adult↗
PubMed2000

[The effect of adding cefobid upon the physiochemical properties of calcium phosphate cement].

This study was conducted to analyze the physiochemical properties of different mass ratio compounds of cefobid-load calcium phosphate cement(CPC). The compounds of 0%, 2.9%, 4.8% and 7.4% mass ratio cefobid-load CPC were made respectively. The setting time was observed; the compressive strength of compounds was measured by a material testing machine; the construction of compounds was observed by scanning electron microscopy(SEM) and analyzed by EIG. The results showed that both the setting time and the ratio of hole did not change obviously after the addition of cefobid, but the ultimate compressive strength decreased slowly and the results of the four groups were (21.98 +/- 1.06)MPa, (21.38 +/- 0.95)MPa, (19.22 +/- 1.11)MPa and (13.5 +/- 1.65)MPa respectively. These data indicate there is no obvious effect on the physicochemical properties of calcium phosphate cement after the addition of cefobid between 0% and 4.8%. The compounds have irregular holes and hence a good ability of compressive strength. It might be a new bone grafting material for the reparation of infection-related bone defects.

Biomechanical Phenomena↗
PubMed2000

[Study on family aggregation of esophageal cancer in Linzhou city].

OBJECTIVE: To investigate family aggregation of esophageal cancer (EC) in Linzhou city, a high risk area for EC. METHODS: A hospital based case-control study were conducted, which included relatives of 118 EC cases and 168 controls. EC incidences in relatives of cases and controls were compared by chi 2 test and risk ratio (RR) was calculated. Heritability (h2) was estimated using the Falconer method. RESULTS: EC incidence of case relatives was significantly higher than that in control relatives. The RR was 3.15 (2.15-4.61) in the first degree relatives and 1.87 (1.26-2.79) in the second degree relatives. The heritability was (53.39 +/- 5.93)% for the first degree relatives and (50.21 +/- 10.75)% for the second degree relatives, while the weighted h2 was (52.26 +/- 3.82)%. CONCLUSION: The genetic factor plays an important role the occurrence of EC in Linzhou city; however, environmental factors should not be ignored.

Adult↗
PubMed2000

[Soil moisture dynamics in forest land and wasteland of Loess Plateau].

The dynamics of soil moisture stored in a wasteland and in a forest land in the sub-humid climate region of the Loess Plateau was measured with neutron moisture meter for three successive years. Within the depth of 0-320 cm, the increment of soil water in the test 3 years was respectively -165.7 mm, -15.2 mm and -115.2 mm at the upper and lower position on north slopes and the lower position on south slope of the wasteland. Soil water increased by 17.2 mm at the upper position on north slope of the Chinese pine forest land, after > 380 mm water was consumed yearly by tree transpiration. It is suggested that forest land is essentially different from wasteland in soil water income/expense. The necessity of conducting the approaches for gaining available water of forest land was put forward.

Seasons↗
PubMed2000

Gonadotropin-releasing hormone agonists and laparoscopy in the treatment of adenomyosis with infertility.

OBJECTIVE: To study the role and value of gonadotropin-releasing hormone agonists (GnRH-a) and laparoscopy for the treatment of adenomyosis with infertility. METHODS: Four cases were seen with adenomyosis and infertility, 3 of these cases also presented local adenomyomata in the posterior uterine wall. GnRH-a Triptorelin (decapeptyl) or Goserelin (Zoladex) therapy was instituted for six months before laparoscopic surgery for coexisting pelvic pathologic infertility factors in one case and after laparoscopic surgery in three cases. RESULTS: All cases remained amenorrheic during GnRH-a therapy. After the GnRH-a therapy, all enlarged uterus (7-10 weeks gestation size) all decreased to normal or near normal size; menstruation returned in 80-90 days and three cases conceived within four menstrual periods after cessation of treatment. In the 4 cases one pregnancy resulted in the birth of a healthy 3150 g male newborn at 38 weeks gestation by cesarean section; one pregnancy was terminated after adenomyomectomy by emergency cesarean section at 30 weeks gestation because of threatened rupture of uterus; one case was then normal at 28 weeks pregnancy; the last case had 2 resumptive menstrual periods and was still being followed up. CONCLUSIONS: GnRH-a is markedly efficient in reducing adenomyotic uterine size, facilitates uterine or endometrial receptivity for embryos and enhances uterine ability to maintain pregnancy. For adenomyomata associated with infertility, GnRH-a instead of surgical removal of lesions, which are deep in the myometrium, may avoid uterine rupture when pregnancy occurs. For infertility, GnRH-a treatment before laparoscopic surgery greatly decreases surgical difficulties and blood loss in certain cases.

Adult↗
PubMed2000

[Evaluation of exercise performance and quality of life after lung volume reduction surgery for severe emphysema].

OBJECTIVE: To evaluate grade of dyspnea, exercise performance and quality of life pre and post-lung volume reduction surgery in patients with severe emphysema. METHODS: Serial measurement of lung function, cardiopulmonary exercise test and 6-minute walk distance, and the dyspnea grade assessment by modified dyspnea scale of English Medical Research Council and quality of life by Notting-ham Health Profile were all done before and at 3, 6, 12 months after surgery. RESULTS: FVC, FEV1, MVV increased (P < 0.01) and RV, TLC, RV/TLC decreased at 3, 6, 12 months after surgery (P < 0.01), WATT, TET, VO2max, VO2max/HR, VEmax, VTmax, 6MWD were all improved (P < 0.01), and the dyspnea grade was declined as well as the NHP score(P < 0.01 or < 0.05). CONCLUSION: Lung volume reduction surgery in patients with severe emphysema may improve patient's exercise performance and quality of life.

Evaluation Studies as Topic↗