Biomedical subjects

Qi Zhou

Publications and source records attributed to Qi Zhou.

At least 55 records · Page 3Linked to original sources

PubMed2005

Mesenchymal stem cells participating in ex vivo endothelium repair and its effect on vascular smooth muscle cells growth.

BACKGROUND: Previous studies have shown that mesenchymal stem cells (MSCs) transplantation can promote neovascularization and regenerate damaged myocardium. However, it remains unknown whether MSCs seeding can be used to repair injured cellular components in vascular diseases. In this study we explored the feasibility of applying MSCs to endothelium repair in endothelial damage and vasoproliferative disorders. METHODS: Ex vivo model of endothelium repair was developed in which rabbit vascular smooth muscle cells (SMCs) were inoculated into the upper chamber and rabbit endothelial cells (ECs)/human MSCs into the lower chamber of a co-culture system. 3H-TdR incorporation and PCNA protein expression were assayed and migrated number of SMCs was calculated to evaluate the effect of MSCs seeding on SMCs growth. Flk-1 and vWF protein expressions were observed to analyze the plasticity of the seeded MSCs along endothelial lineage. RESULTS: In this co-culture system, no vWF protein but Flk-1 protein was observed in the 25.71% of MSCs after having been co-cultured with mature rabbit ECs for 5 days. Compared with the control group, the proliferation and migration of SMCs was significantly increased by proliferative ECs but decreased by confluent ECs (n=6, P<0.01). MSCs seeding decreased the proliferation and migration of SMCs compatible with the effect of proliferative ECs (n=6, P<0.001). However, no inhibition on SMCs growth was observed with MSCs seeding in comparison to the effect of confluent ECs. CONCLUSIONS: MSCs seeding can inhibit the proliferation and migration of SMCs. MSCs co-cultured with mature ECs have the ability to undergo milieu-dependent differentiation toward ECs.

Animals↗

PubMed2005

Nuclear transfer of M-phase ferret fibroblasts synchronized with the microtubule inhibitor demecolcine.

The development of reconstructed embryos following nuclear transfer (NT) appears to be dependent upon a variety of factors, including cell cycle synchronization between the donor nucleus and recipient oocyte. Here we use the microtubule inhibitor, demecolcine, to synchronize ferret fibroblasts in metaphase (M-phase) in order to match their cell cycle position with that of the recipient oocyte at the time of NT. The fibroblasts were obtained from 28-day fetuses and cultured for 1-30 days prior to NT. Fibroblast cultures were treated with 0.05 microg/ml of demecolcine for 3 hr or overnight (14-16 hr) after various times in culture to determine the optimal conditions for M-phase synchronization. The percentage of G2/M-phase cells in demecolcine-treated cultures was significantly greater than that found in untreated cultures (P<0.05). Optimally synchronized M-phase fibroblasts were collected by mitotic shake-off and evaluated for their effectiveness in NT. M-phase somatic cell-derived NT embryos reconstituted by electrofusion or microinjection underwent implantation and formed fetuses at similar rates (5.4% vs. 3.4%, and 1.8% vs. 1.2%, respectively); however, no NT embryos developed to term. In summary, these data demonstrate two important points. First, demecolcine treatment effectively synchronizes ferret fibroblasts in M-phase of the cell cycle; and second, these somatic cells are capable of driving embryo development following NT. Our results should facilitate the development of cloned ferrets as an animal model for human lung disease such as influenza and cystic fibrosis.

Analysis of Variance↗

PubMed2005

Randomized trials stopped early for benefit: a systematic review.

CONTEXT: Randomized clinical trials (RCTs) that stop earlier than planned because of apparent benefit often receive great attention and affect clinical practice. Their prevalence, the magnitude and plausibility of their treatment effects, and the extent to which they report information about how investigators decided to stop early are, however, unknown. OBJECTIVE: To evaluate the epidemiology and reporting quality of RCTs involving interventions stopped early for benefit. DATA SOURCES: Systematic review up to November 2004 of MEDLINE, EMBASE, Current Contents, and full-text journal content databases to identify RCTs stopped early for benefit. STUDY SELECTION: Randomized clinical trials of any intervention reported as having stopped early because of results favoring the intervention. There were no exclusion criteria. DATA EXTRACTION: Twelve reviewers working independently and in duplicate abstracted data on content area and type of intervention tested, reporting of funding, type of end point driving study termination, treatment effect, length of follow-up, estimated sample size and total sample studied, role of a data and safety monitoring board in stopping the study, number of interim analyses planned and conducted, and existence and type of monitoring methods, statistical boundaries, and adjustment procedures for interim analyses and early stopping. DATA SYNTHESIS: Of 143 RCTs stopped early for benefit, the majority (92) were published in 5 high-impact medical journals. Typically, these were industry-funded drug trials in cardiology, cancer, and human immunodeficiency virus/AIDS. The proportion of all RCTs published in high-impact journals that were stopped early for benefit increased from 0.5% in 1990-1994 to 1.2% in 2000-2004 (P<.001 for trend). On average, RCTs recruited 63% (SD, 25%) of the planned sample and stopped after a median of 13 (interquartile range [IQR], 3-25) months of follow-up, 1 interim analysis, and when a median of 66 (IQR, 23-195) patients had experienced the end point driving study termination (event). The median risk ratio among truncated RCTs was 0.53 (IQR, 0.28-0.66). One hundred thirty-five (94%) of the 143 RCTs did not report at least 1 of the following: the planned sample size (n = 28), the interim analysis after which the trial was stopped (n = 45), whether a stopping rule informed the decision (n = 48), or an adjusted analysis accounting for interim monitoring and truncation (n = 129). Trials with fewer events yielded greater treatment effects (odds ratio, 28; 95% confidence interval, 11-73). CONCLUSIONS: RCTs stopped early for benefit are becoming more common, often fail to adequately report relevant information about the decision to stop early, and show implausibly large treatment effects, particularly when the number of events is small. These findings suggest clinicians should view the results of such trials with skepticism.

Clinical Trials Data Monitoring Committees↗

PubMed2005

27-Hydroxycholesterol causes remodeling in endothelial cell membrane lipid composition comparable to remodeling in the failed vein grafts of CABG patients.

Our objective is to determine if vascular remodeling in CABG patients is related to oxysterols, therefore, we compared failed vein grafts from 18 patients, available after a second coronary artery bypass grafting (CABG), with human endothelial cells (ECs). The ECs were cultured in minimum essential medium (MEM) with or without 27-hydroxycholesterol (27OHC), one of the oxysterol products of oxidatively modified low density lipoproteins (ox-LDL), as an agent to alter molecular mechanisms in vascular cells. Significant changes in phospholipid composition, in fatty acid profile and in calcium concentration were found in the failed vein compared to the native saphenous vein from the same (CABG) patient. The failed vein contained significantly less phosphatidylethanolamine, more sphingomyelin, less arachidonic acid, more linoleic acid and more calcium than the native saphenous vein. Comparable changes in phospholipid composition, in fatty acid profile and increased calcium influx were reproduced in ECs cultured in medium containing 27OHC indicating that an oxysterol is an agent that can alter the lipid composition of vascular cell membranes. Our study indicates that a lipid agent, as well as protein agents that have previously been linked to the process of vascular remodeling, may be fundamental to many vascular diseases.

Calcium↗

PubMed2005

Transplantable neural progenitor populations derived from rhesus monkey embryonic stem cells.

Cell-based therapies using embryonic stem cells (ESCs) in the treatment of neural disease will require the generation of homogenous donor neural progenitor (NP) populations. Here we describe an efficient culture system containing hepatocyte growth factor (HGF) and G5 supplement for the production of highly enriched (88.3%+/-8.1%) populations of NPs from rhesus monkey ESCs. Additional purification resulted in NP preparations that were 98% nestin positive. Moreover, NPs, as monolayers or neurospheres, could be maintained for prolonged periods of time in media containing HGF+G5 or G5 alone. In vitro differentiation and in vivo transplantation assays showed that NPs could differentiate into neurons, astrocytes, and oligodendrocytes. The kinds and quantities of differentiated cells derived from NPs were closely correlated with their niches in vivo. Glial differentiation was predominant in periventricular areas, whereas cells migrating into the cortex were mostly neurons. Cell counts showed that 2 months after transplantation, approximately 25% of transplanted NPs survived and 65%-80% of the surviving transplanted cells migrated along the ventricular wall or in a radial fashion. Subcloning demonstrated that several clonal lines derived from NPs expressed nestin and differentiated into three neural lineages in vitro and in rat brains in vivo. In contrast, some subcloned lines showed restricted differentiation both in vitro and in vivo in rat brains. These observations set the stage for obtaining highly enriched NPs and evaluating the efficacy of NP-based transplantation therapy in the nonhuman primate and will provide a platform for probing the molecular mechanisms that control neural induction.

Animals↗

PubMed2005

Homologous feeder cells support undifferentiated growth and pluripotency in monkey embryonic stem cells.

In the present study, five homologous feeder cell lines were developed for the culture and maintenance of rhesus monkey embryonic stem cells (rESCs). Monkey ear skin fibroblasts (MESFs), monkey oviductal fibroblasts (MOFs), monkey follicular granulosa fibroblast-like (MFG) cells, monkey follicular granulosa epithelium-like (MFGE) cells, and clonally derived fibroblasts from MESF (CMESFs) were established and compared with the ability of mouse embryonic fibroblasts (MEFs) to support rESC growth. MESF, MOF, MFG, and CMESF cells, but not MFGE cells, were as good as or better than MEFs in supporting undifferentiated growth while maintaining the differentiation potential of the rESCs. In an effort to understand the unique properties of supportive feeder cells, expression levels for a number of candidate genes were examined. MOF, MESF, and MEF cells highly expressed leukemia inhibitory factor, ciliary neurotrophic factor, basic fibroblast growth factor, stem cell factor, transforming growth factor beta1, bone morphogenetic protein 4, and WNT3A, whereas WNT2, WNT4, and WNT5A were downregulated, compared with MFGE cells. Additionally, all monkey feeder cell lines expressed Dkk1 and LRP6, antagonists of the WNT signaling pathway, but not WNT1, WNT8B, or Dkk2. rESCs grown on homologous feeders maintained normal karyotypes, displayed the characteristics of ESCs, including morphology, alkaline phosphatase, Oct4, the cell surface markers stage-specific embryonic antigen (SSEA)-3, SSEA-4, tumor-related antigen (TRA)-1-60, and TRA-1-81, and formed cystic embryoid bodies in vitro that included differentiated cells representing the three major germ layers. These results indicate that the four homologous feeder cell lines can be used to support the undifferentiated growth and maintenance of pluripotency in rESCs.

Animals↗

PubMed2005

Transposon-mediated generation of targeting vectors for the production of gene knockouts.

Vectors used for gene targeting experiments usually consist of a selectable marker flanked by two regions of homology to the targeted gene. In a homologous recombination event, the selectable marker replaces an essential element of the target gene rendering it inactive. Other applications of gene targeting technology include gene replacement (knockins) and conditional vectors which allow for the generation of inducible or tissue-specific gene-targeting events. The assembly of gene-targeting vectors is generally a laborious process requiring considerable technical skill. The procedures presented here report the application of transposons as tools for the construction of targeting vectors. Two mini-Mu transposons were sequentially inserted by in vitro transposition at each side of the region targeted for deletion. One such transposon carries an antibiotic resistance marker suitable for selection in mammalian cells. A deletion is then generated between the two transposons either by LoxP-induced recombination or by restriction digestion followed by ligation. This deletion removes part of both transposons plus the targeted region in between, leaving a transposon carrying the selectable marker flanked by two arms which are homologous to the targeted gene. Targeting vectors constructed using these transposons were electroporated into embryonic stem cells and shown to be effective in gene-targeting events.

Animals↗

PubMed2005

No major effect of the insulin-like growth factor I gene on bone mineral density in premenopausal Chinese women.

Osteoporosis is a major public health problem, mainly characterized by low bone mineral density (BMD). BMD is a complex trait that is determined by multiple genes. Insulin-like growth factor I (IGF-I) is an important growth factor of bone and thus IGF-I gene has been considered as an attractive candidate gene for osteoporosis. A few studies on the relationship between variants of the IGF-I gene and BMD variation, via traditional association and/or linkage methods, have yielded conflicting results. In this study, we simultaneously tested association and/or linkage of a cytosine-adenine (CA) repeat polymorphism at 1 kb upstream of the transcription initiation site of the IGF-I gene with BMD variation in a large cohort of premenopausal Chinese women. A total of 1263 subjects from 402 Chinese nuclear families were examined. Each family consists of both parents and at least one daughter aged between 20 and 45 years. BMDs (g/cm(2)) at the lumbar spine and hip were measured using dual-energy X-ray absorptiometry (DXA). Applying the QTDT (quantitative transmission disequilibrium tests) progam, we did not find significant evidence of association or linkage between the CA repeat polymorphism of the IGF-I gene and BMD variation at any skeletal site. Our data do not support the IGF-I gene having major effect on BMD variation in premenopausal Chinese women.

Alleles↗

PubMed2005

Cytological screening and 15 years' follow-up (1986-2001) for early esophageal squamous cell carcinoma and precancerous lesions in a high-risk population in Anyang County, Henan Province, Northern China.

BACKGROUND: Anyang County and nearby Linzhou (formerly Linxian) in Henan, Northern China have been well recognized as the highest incidence area for esophageal squamous cell carcinoma (SCC) in the world. SCC remains the leading cause of cancer-related death in these areas and the natural history for esophageal precancerous lesions is not clear. METHODS: In the present study, to determine the significance of cytological examination and natural history for SCC, esophageal balloon cytological screening and follow-up studies have been performed 2273 symptom-free subjects in Anyang County since 1986. Based on cellular morphological changes, esophageal epithelial cells were classified as normal (NOR), inflammation (IN), hyperplasia (HYP), dysplasia (grades I and II) (DYS I and DYS II), near squamous cell carcinoma (NSCC) and SCC. RESULTS: The prevalence of NOR, IN, HYP, DYS I, DYS II, and NSCC was 22.7, 3.6, 33.6, 21.5, 10.7, and 3.8%, respectively, in males and 25.8, 5.7, 33, 18.9, 10.4, and 3.8%, respectively in females. No difference was observed between the male and female subjects (p > 0.05). Of the 2273 subjects examined, 2199 subjects entered the final follow-up analysis (97%). During the 15 years' follow-up on these subjects, 94 new cases (4.2%, 94/2199), including 91 with SCC (97%, 91/94, 58 males and 33 females) and 3 with GCA (3%, 3/94, one male and two females) were identified with a mean time of 8 +/- 4.6 years after entry of the follow-up. The incidence for SCC in males was higher than that in females (p < 0.05). The rate for SCC development increased apparently from the groups of NOR (2.4%) to DYS I (5%), DYS II (8.3%), and NSCC (10.3%) (p < 0.001). The prevalence of DYS and NSCC increased significantly with age. CONCLUSIONS: The present results indicate that esophageal balloon cytology is a reliable approach for early SCC and precancerous lesions screening and that DYS and NSCC are important markers for high-risk subjects with predisposition to SCC. Close follow-up to the subjects with HYP, DYS and NSCC may shed light on the natural history for human esophageal carcinogenesis.

Adult↗

PubMed2005

Effect of paclitaxel and mesenchymal stem cells seeding on ex vivo vascular endothelial repair and smooth muscle cells growth.

Late thrombosis and neointima proliferation after paclitaxel-eluting stents implanting may be related to delayed endothelial cells (ECs) regeneration. This study was to investigate whether mesenchymal stem cells (MSCs) seeding can accelerate endothelial repair and attenuate late smooth muscle cells (SMCs) proliferation after paclitaxel intervention. An ex vivo model of endothelium repair was developed in which rabbit smooth muscle cells were inoculated in the upper chamber and rabbit endothelial cells/human mesenchymal stem cells in the lower chamber of a co-culture system. Paclitaxel (10 nmol/L, 20 min) inhibited smooth muscle cell growth of the confluent endothelial cell group during the observed period. However, increased smooth muscle cells growth was observed in the proliferative endothelial cells group 10 days after paclitaxel intervention. Mesenchymal stem cell seeding inhibited late smooth muscle cell growth incompatible with the effect of proliferative endothelial cells. However, no inhibition on smooth muscle cell growth was observed with mesenchymal stem cell seeding in comparison to the effect of confluent endothelial cells. No vWF but Flk-1 protein was observed in the 25.71% of mesenchymal stem cells after having been co-cultured with rabbit endothelial cells for 5 days. These results indicate that late smooth muscle cell proliferation is closely related to the delayed endothelial cells regeneration after paclitaxel application. Mesenchymal stem cell seeding partly attenuates the late smooth muscle cell proliferation. Mesenchymal stem cells co-cultured with mature endothelial cells have the ability to differentiate toward endothelial cells.

Animals↗

PubMed2005

Sonographic and Doppler imaging in the diagnosis and treatment of gestational trophoblastic disease: a 12-year experience.

OBJECTIVE: To evaluate the clinical utility of sonography with Doppler examination in the diagnosis and treatment of gestational trophoblastic disease (GTD). METHODS: A retrospective analysis of 355 cases of GTD seen over a 12-year period in 2 large university referral hospitals in China was performed. Clinical appearances, sonographic findings, Doppler waveforms, and patient outcomes were reviewed. Sonographic and Doppler examinations were performed to diagnose the presence of molar tissue, detect invasive disease, assess disease recurrence, and monitor the efficacy of chemotherapy. Doppler waveforms of 13 patients with normal early pregnancies were also examined for comparison. RESULTS: Of the 355 patients with GTD, 106 had a classic hydatidiform mole (CHM), 33 had a partial hydatidiform mole (PHM), 184 had an invasive hydatidiform mole (IHM), and 32 had choriocarcinoma. Sonography showed abnormal molar tissue confined to the endometrial cavity in all cases of CHM. In cases of IHM and choriocarcinoma, soft tissue invasion and cystic vascular spaces within the myometrium were shown. Cases of PHM had a thickened, hydropic placenta with a concomitant fetus. Doppler waveforms showed resistive indices of 0.55 (SD, 0.06) for CHM, 0.56 (SD, 0.04) for PHM, 0.28 (SD, 0.06) for IHM, 0.25 (SD, 0.05) for choriocarcinoma, and 0.66 (SD, 0.04) for normal pregnancies. The abnormal sonographic and Doppler findings in invasive disease resolved when chemotherapy was successful. CONCLUSIONS: Sonography and Doppler imaging were helpful in diagnosing GTD, in determining whether invasive disease was present, in detecting recurrence of disease, and in following the effectiveness of chemotherapy.

Adult↗

PubMed2005

[Effects of paclitaxel combined with bone marrow stromal stem cells implantation on vascular endothelial repair and smooth muscle cells growth in vitro].

OBJECTIVE: To investigate the effects of paclitaxel combined with bone marrow stromal stem cells (MSCs) implantation on inhibiting the smooth muscle cells (SMCs) growth and promoting endothelial repair by developing an endothelial repair model in vitro. METHODS: In a cell coculture system, rabbit endothelial cells (ECs) and human MSCs were seeded in the lower chamber and rabbit SMCs were seeded in the upper chamber. 3H-TdR incorporation and PCNA protein expression were used to evaluate SMCs proliferation at the 10th day after paclitaxel application (1, 10, 100 nmol/L; 20 min). Fluorescence immunocytochemistry was employed to observe the Flk-1 and vWF protein expression on MSCs. RESULTS: The SMCs 3H-TdR incorporation of the MSCs implant group was significantly lower than that of the proliferative ECs group (1 nmol/L: 12 265 +/- 991 vs. 14 505 +/- 1013 cpm/well; 10 nmol/L: 8401 +/- 783 vs. 10 511 +/- 934 cpm/well; 100 nmol/L: 5880 +/- 569 vs. 7457 +/- 768 cpm/well, n = 6, P < 0.05), but higher than that of the confluent ECs group (1 nmol/L: 12 265 +/- 991 vs. 8671 +/- 642 cpm/well; 10 nmol/L: 8401 +/- 783 vs. 6175 +/- 743 cpm/well; 100 nmol/L: 5880 +/- 569 vs. 4423 +/- 406 cpm/well, n = 6, P < 0.05). The expression of SMCs PCNA protein in MSCs implant group was lower than that of the proliferative ECs group (1 nmol/L: 0.92 +/- 0.06 vs. 1.15 +/- 0.07; 10 nmol/L: 0.97 +/- 0.07 vs. 1.07 +/- 0.08; 100 nmol/L: 0.91 +/- 0.05 vs. 1.18 +/- 0.11, n = 6, P < 0.05), but higher than that of the confluent ECs group (1 nmol/L: 0.92 +/- 0.06 vs. 0.74 +/- 0.07; 10 nmol/L: 0.97 +/- 0.07 vs. 0.78 +/- 0.06; 100 nmol/L: 0.91 +/- 0.05 vs. 0.71 +/- 0.05, n = 6, P < 0.05). The MSCs did not express vWF or Flk-1 protein before coculture. Although none cell expressed vWF, some of the MSCs began to express Flk-1 protein after cocultured with mature ECs for 10 days. CONCLUSION: MSCs implantation can partly inhibit the delayed SMCs proliferation. The MSCs cocultured with paclitaxel-treated mature ECs have the ability to differentiate into ECs.

Bone Marrow Cells↗

PubMed2005

[Clinical evaluation on surgical implant anchorage in orthodontic and prosthodontic therapy].

PURPOSE: To evaluate the clinical effect of implant anchorage in the correction of malocclusion and restoration of dentition defects. METHODS: 14 cases who had Angle II malocclusion as well as dentition defects and whose molars could not serve as anchorage or who had no molars at all were selected. Implants in the maxilla or mandible were served first as anchorage to correct the malocclusion and then to restore the dentition defects. RESULTS: The implant anchorage in the palate didn't move medially after the anterior teeth had been adducted by 6-8 mm. 3 cases of zygo-alveolar ridge implantation failed. 5 cases of adult Angle II division I, II malocclusions as well as Kennedy II dentition defects were orthodontically treated for 8-10 months, the lower anterior teeth were adducted by 6-8mm, aligned and the midline was corrected with no medial movement of the implant anchorage. Then the implants were used to restore the missing teeth. CONCLUSION: It is feasible and effective to use implant as anchorage in orthodontic and prosthodontic treatment in cases without available anchorage.

Dental Implantation, Endosseous↗

PubMed2005

Value of ultrasound in the diagnosis of congenital renal malformations.

OBJECTIVE: To assess the value of ultrasound in diagnosis of congenital renal malformations. METHODS: The records of obstetric ultrasound examinations were reviewed in all the pregnant women admitted in Alta Bates Perinatal Diagnostic center (Oakland, California, USA) during 5 years. RESULTS: Ultrasound examination identified 58 cases of congenital renal malformations of different kinds, including 4 cases of renal agenesis, 8 multicystic dysplastic kidney, 5 cystic renal dysplasia with obstructions, 6 renal and ureteral duplications, 6 ectopic kidneys, 18 hydronephroses, 3 autosomal recessive polycystic kidney diseases, 2 autosomal dominant polycystic diseases, 1 Finnish-type congenital nephrosis, 3 Meckel-Gruber syndromes, and 2 Beckwith-Wiedemann syndromes. Different renal malformations had different ultrasound findings that correlated to abnormalities in embryonic developments. CONCLUSIONS: Urinary tract abnormalities have a profound effect on pregnancy outcome, especially when associated with oligohydramnios. Many urinary anomalies can be readily detected and diagnosed by ultrasound, which provides a useful modality in diagnosis of fetal congenital renal malformations. Clear understanding of the causes of these abnormalities facilitates prognostic evaluation and clinical decision on the treatment protocol.

Adult↗

PubMed2005

[Effects of plants on nitrogen/phosphorus removal in subsurface constructed wetlands].

Effects of plants on nitrogen/phosphorus removal was studied in pilot-scale in subsurface constructed wetland, the main contents included nutrient uptake, effects of harvesting and roots on hydraulic condition. The result show that the amounts of nitrogen and phosphorous removed by plant harvesting is about 5% of the total removed nutrients in SFS wetlands. The best harvesting periods is between 9-10 month every year. Plant harvesting may induce fluctuation of outflow; aboveground biomass can stabilize micro-environmental of roots. The roots can also improve hydraulic condition of SFS system, decreasing dead area 5 % - 10 % and extending hydraulic retention time.

Biodegradation, Environmental↗

PubMed2004

27-Hydroxycholesterol inhibits neutral sphingomyelinase in cultured human endothelial cells.

To study the effect of 27-hydroxycholesterol (27OHC) on the catabolism of sphingomyelin, we cultured endothelial cells (ECs) from human umbilical veins with 27OHC, then measured activities of acid sphingomyelinase (ASMase) and neutral sphingomyelinase (NSMase) and sphingomyelin consumption by using [14C]sphingomyelin, and determined NSMase mRNA expressions by RT-PCR method. The results indicated that [14C]sphingomyelin accumulated in cells treated with 27OHC, and that the activities of both NSMase and ASMase were inhibited in ECs cultured with 27OHC. To further study the effect of 27OHC on NSMase, we used desipramine, an inhibitor of ASMase, to exclude the possible interference of ASMase's residual activity at neutral condition. Also, we observed the significant inhibition of NSMase activity by using glutathione, an inhibitor of NSMase, but found no further impact when 27OHC was added later. To determine whether the inhibition of NSMase activity was directly due to the effect of 27OHC, we exposed cell homogenate to 27OHC, and found no inhibitive effect of 27OHC on the activity of NSMase. All of our data confirmed that 27OHC had only an indirect inhibitive effect on NSMase. Our finding that no change of the NSMase mRNA expression by 27OHC indicated that the inhibitive effect of 27OHC on NSMase activity occurred at a post-transcriptional level. We suggest that an altered membrane fluidity caused by 27OHC could be involved in the inhibited activity of NSMase.

Analysis of Variance↗

PubMed2004

Activation of crystalline cellulose surfaces through the chemoenzymatic modification of xyloglucan.

Cellulose constitutes an important raw material for many industries. However, the superb load-bearing properties of cellulose are accompanied by poor chemical reactivity. The hydroxyl groups on cellulose surfaces can be reacted but usually not without loss of fiber integrity and strength. Here, we describe a novel chemoenzymatic approach for the efficient incorporation of chemical functionality onto cellulose surfaces. The modification is brought about by using a transglycosylating enzyme, xyloglucan endotranglycosylase, to join chemically modified xyloglucan oligosaccharides to xyloglucan, which has a naturally high affinity to cellulose. Binding of the chemically modified hemicellulose molecules can thus be used to attach a wide variety of chemical moieties without disruption of the individual fiber or fiber matrix.

Cellulose↗

PubMed2004

Trans fatty acids in hydrogenated fat inhibited the synthesis of the polyunsaturated fatty acids in the phospholipid of arterial cells.

Our hypothesis that the trans fatty acids in hydrogenated fat inhibited the synthesis of polyunsaturated fatty acids in the phospholipid of arterial cells was tested with five groups each with six pregnant porcine fed from d 35 of gestation and during lactation. The basal diet contained 2% corn oil (control). The other four diets included the control + 10% butter or 10% hydrogenated fat plus two levels of Mg. Plasma, milk and aortic phospholipid fatty acids, phospholipid composition and calcium content of the aorta from the piglets were determined. At 48 +/- 2 d of age, the aorta phospholipid of piglets from porcine fed hydrogenated fat contained a significantly higher concentration of linoleic acid, less arachidonic acid, and less long chain polyunsaturated fatty acid (PUFA) than did piglets from porcine fed either butterfat or the control diet. Mg had no effect. These changes in composition in piglets from porcine fed hydrogenated fat indicate that trans fat inhibits the metabolic conversion of linoleic acid to arachidonic acid and to other n-6 PUFA. The aortic calcium content data showed a significant interaction of calcium concentration with age. We concluded: 1) that dietary trans fat perturbed essential fatty acid (EFA) metabolism which led to changes in the phospholipid fatty acid composition in the aorta, the target tissue of atherogenesis, 2) this inhibition of EFA to PUFA by the isomeric fatty acids in hydrogenated fat is a risk factor in the development of coronary heart disease.

Age Factors↗