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Biomedical subjects

Mei Wang

Publications and source records attributed to Mei Wang.

At least 91 records · Page 5Linked to original sources
PubMed2005

Abscisic acid and 14-3-3 proteins control K channel activity in barley embryonic root.

Germination of seeds proceeds in general in two phases, an initial imbibition phase and a subsequent growth phase. In grasses like barley, the latter phase is evident as the emergence of the embryonic root (radicle). The hormone abscisic acid (ABA) inhibits germination because it prevents the embryo from entering and completing the growth phase. Genetic and physiological studies have identified many steps in the ABA signal transduction cascade, but how it prevents radicle elongation is still not clear. For elongation growth to proceed, uptake of osmotically active substances (mainly K(+)) is essential. Therefore, we have addressed the question of how the activity of K(+) permeable ion channels in the plasma membrane of radicle cells is regulated under conditions of slow (+ABA) and rapid germination (+fusicoccin). We found that ABA arrests radicle growth, inhibits net K(+) uptake and reduces the activity of K(+) (in) channels as measured with the patch-clamp technique. In contrast, fusicoccin (FC), a well-known stimulator of germination, stimulates radicle growth, net K(+) uptake and reduces the activity of K(+) (out) channels. Both types of channels are under the control of 14-3-3 proteins, known as integral components of signal transduction pathways and instrumental in FC action. Intriguingly, 14-3-3 affected both channels in an opposite fashion: whereas K(+) (in) channel activity was fully dependent upon 14-3-3 proteins, K(+) (out) channel activity was reduced by 14-3-3 proteins by 60%. Together with previous data showing that 14-3-3 proteins control the activity of the plasma membrane H(+)-ATPase, this makes 14-3-3 a prime candidate for molecular master regulator of the cellular osmo-pump. Regulation of the osmo-pump activity by ABA and FC is an important mechanism in controlling the growth of the embryonic root during seed germination.

14-3-3 Proteins↗
PubMed2005

Pial arterial response to topical verapamil in acute closed cranial windows in rabbits.

We have previously observed that intraarterial verapamil increases cerebral blood flow, whereas nitric oxide donors, such as nitroglycerin, do not. Clinically, both verapamil and nitroglycerin dilate large cerebral arteries. Therefore, we hypothesized that topical verapamil would dilate both the large proximal and the small distal cerebral arteries, whereas nitroglycerin would preferentially dilate only the large proximal arteries. We tested our hypothesis in acute cranial windows implanted in 10 New Zealand White rabbits. After predrug measurements, we superfused 4 increasing concentrations of verapamil or nitroglycerin (10(-8), 10(-6), 10(-4), and 10(-3) M) in the cranial windows for 5 min each. The maximum increase in diameter was expressed as a percentage change from predrug diameters. There was a 30-min period of rest between the two drug challenges. Topical verapamil increased the arterial diameter of the larger proximal arterioles (>60 microm) by 32% +/- 18% and that of the smaller distal arterioles (<60 microm) by 62% +/- 42%. A modest increase in arterial diameters of 11% +/- 11% was observed after topical nitroglycerin that was significant only for the large-proximal arterioles. Within the 10(-8) to 10(-3) M range, topical verapamil, compared with nitroglycerin, proved to be a more potent cerebral vasodilator and had a more robust vasodilator effect on the distal small pial arteries.

Administration, Topical↗
PubMed2005

Reducing cerebral blood flow increases the duration of electroencephalographic silence by intracarotid thiopental.

The effects of IV anesthetics are enhanced by increased cerebral blood flow (CBF) because of a greater delivery of drugs to the brain. In contrast, mathematical simulations suggest that a decrease in CBF, by increasing regional drug uptake and decreasing drug washout, enhances the efficacy of intraarterial drugs. We hypothesized that administrating intracarotid anesthetics during cerebral hypoperfusion will significantly prolong the duration of electroencephalographic (EEG) silence. We tested our hypothesis on New Zealand White rabbits. In the first group of 7 animals, we observed that decreasing CBF by approximately 70% attenuated, but did not abolish, EEG activity. Subsequently, 9 animals received 3 intracarotid injections of 3 mg of thiopental (thiopental-1, thiopental + hypoperfusion, and thiopental-2). The first and third injections were made under physiological conditions. The second drug injection was made during cerebral hypoperfusion. Compared with injection of thiopental-1 and -2, thiopental + hypoperfusion resulted in a profound increase in EEG silence (from 45 +/- 5 and 67 +/- 27 s, to 206 +/- 46 s, respectively, n = 9, P < 0.0001). The EEG recovery profile was similar during all three thiopental challenges. The study suggests that modulation of CBF is an important tool for enhancing intraarterial drug delivery to the brain.

Adenosine↗
PubMed2005

Histologic and mechanical evaluation of impaction grafting for femoral component revision in a goat model.

A goat model of revision hip arthroplasty was used to examine the histology and mechanical performance of impaction grafting using two femoral stems varying in stem surface finish. There were no significant mechanical or qualitative histologic differences between smooth, tapered, polished stems and step-cut, grit-blasted stems. Allograft distribution, bone incorporation, and cement mantle thickness were not uniform within the femoral canal. Efforts to improve the impaction grafting technique may be more important than stem design.

Animals↗
PubMed2005

[Comparative study on various subpopulations in mesenchymal stem cells of adult bone marrow].

To explore the difference of biological characteristics between two subpopulations of adult bone marrow mesenchymal stem cells (MSC), this study was designed to observe the morphological feature and immunophenotype of the adult MSC in the ex vivo culture, the mononuclear cells isolated from normal adult bone marrow were cultured in DMEM with 10% fetal bovine serum. Cell morphology, immunophenotype and cell cycle of two different subgroups were investigated. Cells from 80% confluence were passed through a 10 microm filter, then the fillered cells were cultured in the semisolid methylcellulose medium. The results showed that (1) two different subpopulations were observed in the ex vivo culture. The fibro-like cell was called mature MSC (mMSC) and the smaller round cell was defined rapidly as MSC self-renewing cells (RS cells); (2) the average proportion of cells in G(0)/G(1) of RS cells was approximately 99%, but that of mMSCs was 90%; (3) both of the two populations were negative on the lineage-committed antigen (such as CD34, CD45, CD3, CD19, CD33, HLA-DR, CD38), while positive on the expression of CD90, CD105, C166, CD29, CD44, CD49e, CD54, CD13. However, the expression of these antigens on RS cells was weaker than that on mMSC, but CD117 and KDR were higher expressed when compared with the mMSC; (4) after 4 to 5 week semisolid culture, no hematopoietic progenitor cell colonies were observed. It is concluded that adult MSCs are heterogeneous in that distinct morphological populations exist. The RS cells appear to be the more primitive with greater potential for self-renewal and multilineage differentiation.

Adult↗
PubMed2005

Comparisons between oral pulse alfacalcidol therapy and daily therapy in maintenance hemodialysis patients with secondary hyperparathyroidism: a randomized, controlled, and multicenter study.

OBJECTIVE: To investigate the efficacy and safety of 1alpha-(OH)-D3 high-dose pulse therapy or daily low-dose therapy in secondary hyperthyroidism in maintenance hemodialysis patients in China. METHODS: Maintenance hemodialysis patients of both gender with intact parathyroid hormone (iPTH) level above 200 pg/mL were randomly divided into a pulse group and a daily group. They were treated for 20 weeks, with 2 microg oral Alfacalcidol twice weekly or thrice weekly in the pulse group, and 0.5 microg oral Alfacalcidol per day in the daily group. The therapeutic end point was parathyroid hormone level < 200 pg/ mL. The iPTH levels during the study were monitored, and parameters representative of calcium and phosphate metabolism and side effects were also observed. RESULTS: One hundred and fifty-eight patients were initially enrolled, 91 in the pulse therapy group and 67 in the daily therapy group. There was no significant difference in age, hemodialysis duration, proportion of diabetic nephropathy and systemic diseases, proportion of patients who had received active vitamin D therapy previously, mean initial iPTH level (pulse group 570.47 +/- 295.86 pg/mL; daily group 498.33 +/- 207.84 pg/mL), serum calcium, serum phosphate, alkaline phosphatase (AKP), and albumin between two groups. In the pulse therapy group there were more patients with iPTH levels of 500 to approximately 1,000 pg/mL and > 1,000 pg/mL, so stratified analysis according to iPTH level was used. In therapeutic end point, iPTH levels in both groups were significantly lower compared with those before therapy (pulse group 261.29 +/- 234.97 pg/mL, P < .01; daily group 262.17 +/- 274.82 pg/mL, P < .01). After 4 weeks, the ratio of reaching end point in the pulse group was 35.2%, which was significantly higher than that (19.4%) in the daily group (P < .05). More obvious change was seen in the 200 to approximately 500 pg/mL subgroup by stratified analysis (P < .05), whereas there was no significant difference between the 500 to approximately 1,000 pg/mL and > 1,000 pg/mL subgroup (P > .05). At therapeutic end point, the total ratio of reaching end point did not differ between the two groups, and there were no obvious differences between each subgroup. In the iPTH 200 to approximately 500 pg/mL subgroup, mean iPTH%/week in the pulse group was significantly higher than that in the daily group, and no obvious difference was seen in other subgroups. AKP levels decreased significantly in both groups at therapeutic end point (pulse group 98.42 +/- 54.52 vs. 74.21 +/- 30.68 IU/L, P < .01; daily group 103.3 +/- 68.04 vs. 75.40 +/- 34.12 IU/L, P < .01). On the 4th week, AKP level in pulse group (82.39 +/- 35.23 IU/L) was significantly lower than the initial level (98.42 +/- 54.52 IU/L, P < .05), whereas in the daily group there was no difference between each week. The mean serum calcium, phosphate, and [Ca2+] x [P3+] levels in both groups did not change greatly. Nine patients in the pulse group (9.9%) and 8 patients in the daily group (11.9%) suffered hypercalcemia at least once. Persistent hypercalcemia occurred in 8 patients in the pulse group (8.8%) and 9 patients in the daily group (13.4%), but the difference in proportion did not show statistical significance. The serum phosphate in the daily group was higher after the therapy (1.74 +/- 0.36 vs. 1.89 +/- 0.36 mmol/L, P < .05), whereas that in the pulse group remained unchanged. At therapeutic end point, [Ca2+] x [P3+] level in the daily group was higher than that before the therapy (48.04 +/- 11.71 vs. 55.46 +/- 12.66, P < .05), whereas in the pulse group there was no significant difference. Side effects for both groups were minimal and well tolerated. CONCLUSIONS: Alfacalcidol [1alpha-(OH)-D3] has good and safe effects on secondary hyperparathyroidism in maintenance hemodialysis patients. The efficacy and early effects of pulse therapy are superior to those of daily therapy in moderate hyperparathyroidism patients.

Administration, Oral↗
PubMed2005

[The application of glomerular filtration rate estimation equations in different stages of chronic kidney disease].

OBJECTIVE: To understand the applicability of MDRD equation in Chinese patients with chronic kidney disease (CKD). Glomerular filtration rate (GFR) estimated with MDRD equation, abbreviated MDRD equation and Cockcroft-Gault equation was compared with (99m)Tc-DTPA plasma clearance by dual plasma sampling method in different stages of CKD. METHODS: CKD were diagnosed according to K/DOQI guideline.298 patients with CKD were selected. Patients'sex, age, height and body weight were recorded and plasma creatinine, urea nitrogen and albumin were measured in a single clinical laboratory. (99m)Tc-DTPA plasma clearance was calculated and standardized by body surface area (sGFR). GFRs estimated with MDRD equation 7, abbreviated MDRD equation and Cockcroft-Gault equation (7GFR, aGFR and cGFR) were compared with sGFR in different stages of CKD. RESULTS: There were 165 male and 133 female in the selected 298 patients with CKD;the average age was (52.5 +/- 15.5) years. There was significant difference between the GFRs of the 3 equations with sGFR in different stages of CKD (P < 0.001). 7GFR, aGFR and cGFR were significantly higher than sGFR in CKD stages 5-4; the lower the sGFR, the more the differences. 7GFR, aGFR and cGFR were significantly lower than sGFR in CKD stage 2-1; the higher the sGFR, the more the differences. CONCLUSION: Our results showed that in Chinese population with CKD, MDRD equation 7, abbreviated MDRD equation and Cockcroft-Gault equation overestimate actual GFR in CKD stages 4-5 and underestimate GFR in CKD stages 1-2. These results indicate that MDRD equation and its modifications for estimation of GFR should be amended when applying to Chinese patients with CKD in clinical practice.

Adult↗
PubMed2005

[Ex vivo expansion of Valpha24 natural killer T cells with alpha-galactosylceramide].

OBJECTIVE: To evaluate the method for expanding Valpha24 natural killer T (NKT) cells with alpha-galactosylceramide (alpha-GalCer) ex vivo. METHODS: Mononuclear cells (MNCs) isolated from adult peripheral blood or umbilical cord blood (UCB) were divided into three groups. In Group A1 (n = 5), CD34+ progenitorderived dendritic cells were differentiated in a cytokine-supplemented culture system from cord blood and acted as antigen presenting cells (APC) to induce the expansion of cord blood Valpha24 NKT cells in presence of alpha-GalCer; in Group A2 (n = 5), adult peripheral monocyte-derived dendritic cells (Mo-DC) were used as APC to induce the expansion of adult peripheral NKT cells in presence of alpha-GalCer; whereas in Group B (n = 16), alpha-GalCer was added into adult peripheral MNCs culture system without additional DCs. Cytokine-produce were measured by ELISA, and NKT cells' proliferation ability, cytotoxicity, and suppressive effect on mixed lymphocyte reaction (MLR) were examined by MTT assays. RESULTS: Valpha24 NKT cells in Group A1, A2, and B were expanded up to 128 (95-207), 250.5 (179.6-790.6), and 326 (101-2 136) -fold by day 12, respectively. Adult NKT cells expanded in Group B were markedly better than those in Group A1 (P = 0.038). When stimulating by PMA, the NKT cells had a 3-day stimulate index of 1.80 +/- 0.41; and the secretion ratio of IL-4 to IFN-gamma of UCB or adult peripheral blood NKT cells were 0.30 +/- 0.13 and 0.28 +/- 0.18; and the ex vivo antitumor effect of expanded NKT cells were found in cell line HL60, KG1a, and Raji except for K562; and the suppressive effect of expanded NKT cells or the culture supernatant on MLR were confirmed. CONCLUSIONS: Alpha-GalCer can facilitate the rapid shorttime expansion of Valpha24 NKT cells in presence of IL-2 and IL-15. These expanded NKT cells, kill tumor cell lines, and inhibit can massively excret IL-4 and IFN-gamma allogeneic T-cell response.

Antigens, CD34↗
PubMed2005

[HLA-identical sibling allogeneic hematopoietic stem cell transplantation for chronic myelogenous leukemia in first chronic phase. Analysis of 51 cases].

OBJECTIVE: To evaluate the treatment outcome of HLA-identical sibling allogeneic hematopoietic stem cell transplantation (allo-HSCT) for chronic myelogenous leukemia (CML) patients in first chronic phase (CP(1)). METHODS: Fifty-one patients with CML-CP(1) received HLA-identical sibling allo-HSCT with conditioning regimens of TBI plus Cy or Bu plus Cy. Allogeneic peripheral blood stem cell transplantation (PBSCT) and bone marrow transplantation (BMT) were performed for 28 and 23 patients, respectively. The median follow-up duration was 1434 (60 - 4062) days. RESULTS: Fifty (98.0%) patients were successfully engrafted. Transplant-related mortality occurred in 8 (15.7%) patients. Acute graft-versus-host disease (aGVHD) occurred in 35 (68.6%) patients and 11 (21.6%) patients were grade II-IV, while chronic GVHD (cGVHD) did in 17 (37.8%) patients. Five (7.4%) patients relapsed. The 5-year probability of disease-free survival (DFS) was (79.2 +/- 6.4)%. There was no significant difference in 5-year DFS, death rate and treatment related syndromes between the two conditioning regimens (P > 0.05), and in 5-year DFS, relapse rate and death rate between two transplant choices (P > 0.05). However, the rate of relapse was lower in Bu/Cy group (P < 0.01) and the rate of cGVHD was higher in allo-PBSCT group (P < 0.05). CONCLUSIONS: Allo-HSCT can cure a significant proportion of patients with CML-CP(1). There was no significant difference in DFS between the two different conditioning regimens and between the different transplant choices. Donor lymphocyte infusion is a therapeutic alternative for CML patients relapsed after transplantation.

Adult↗
PubMed2005

[Effects of mesenchymal stem cells on expansion potential and adhesion molecules expression of cord blood CD34+ cells].

OBJECTIVE: To explore the effects of bone marrow mesenchymal stem cells (MSCs) on in vitro expansion potential, the adherent molecules expression of cord blood (CB) CD34(+) cells. METHODS: MSCs were obtained from human bone marrow and their differentiation function and phenotype were identified. CB CD34(+) cells were expanded in culture systems with or without MSC layer. Hematopoietic progenitor cells and adhesion molecules expression were assessed by semisolid culture assay and flow cytometry. RESULTS: Thy-1, SH2, SB10, CD44, CD13, CD49e and CD29 were highly expressed on MSCs with no expressions of CD34, CD45, HLA-DR, CD14 and CD31. The MSCs could differentiate into adipocytes and osteoblasts under specific induction conditions. After culturing on MSCs layer with supplement of cytokines for 8 days, the absolute numbers of nuclear cells, CD34(+), CD34(+)CD38(-), CD34(+)CD62L(+) cells and CFU-Cs were increased by 145.57 +/- 17.89, 37.47 +/- 13.78, 69.78 +/- 50.07, 10.74 +/- 5.89 and 20.73 +/- 5.54-folds, respectively, being significantly higher than that cultured with cytokines alone. The expression of ALCAM, VLA-alpha4, VLA-alpha5, VLA-beta1, HCAM, PECAM and LFA-1 on CD34(+) cells remained unaffected. The expressions of ICAM-1 and L-selectin were downregulated during expansion, while the absolute numbers of CD34(+)CD62L(+) and CD34(+)CD54(+) cells were increased. CONCLUSIONS: MSCs layer improves expansion of CB CD34(+) cells while inhibiting their differentiation and retaining their homing ability.

Antigens, CD34↗
PubMed2005

[Survey on prevalence of 1 526 children with sleep disturbances in age of 2 to 12 years old in Chengdu].

OBJECTIVE: To find out the prevalence of sleep disturbances for children aged 2 to 12 years old in Chengdu. METHODS: Totally 1 600 children aged 2-12 years old were selected from 5 districts in Chengdu and investigated by using questionnaire. RESULTS: All 1 526 survey papers were returned. The average time of every day sleep in each age group (infant group, pre-school age group and school age group) were 12.12 hours, 10.42 hours and 9.47 hours. The sleep time of the children in those three groups were much less than the standard one. The proportion of the prevalence of sleep disturbance was 37.88%. Among them, there were snoring in 5.57%, choke/gargling in 1.25%, sleep inquietude in 7.86%, mouth breathing in 4.59%, sweating in 21.36%, member spasm in 2.82%, molar teeth in 8.26%, night talking in 4.02%, somnambulate in 0.2%, bedwetting in 1.95%, and difficulty falling asleep in 10.75%. There were significant differences shown in different sexes and ages, and in incidence of symptoms of some sleep disturbances. The affecting factors were the co-sleeping, tonsillitis, bronchitis, pollen allergy and their parent's snore. CONCLUSION: The prevalence of sleep disturbances being higher and more severe than before might be due to the less sleeping time in Chengdu in children aged 2 to 12 years old. More attention should be paid by parents, the Ministry of Education and the children's doctors.

Child↗
PubMed2004

Mechanical evaluation of posterior wiring as a supplement to anterior cervical plate fixation.

STUDY DESIGN: An in vitro experimental study was performed to examine 3-dimensional biomechanical stability of cervical fixations. OBJECTIVES: To determine whether posterior interspinous wiring contributes to the rigidity of a single-level motion segment that has been plated anteriorly, and to determine the effects of this combined fixation on intradiscal pressure and spinal motion at the adjacent segments. SUMMARY OF BACKGROUND DATA: Combined anterior and posterior column fixation is being increasingly used in a variety of clinical situations that do not involve complete disruption of the motion segment. The biomechanical validity of combined anterior posterior fixation in the absence of overt posterior ligamentous disruption has not been studied. METHODS: Six human fresh-frozen cadaveric cervical spines (C3-T1) were used. Three-dimensional intersegmental motion and intradiscal pressure were measured while the spine was loaded in flexion, extension, lateral bending, and torsion (up to 2.5 Nm). Fixation stability at the operative level (C5-C6) and influence of the fixation on adjacent segments were evaluated after an anterior plating procedure and combined anterior plating and posterior wiring. RESULTS: Comparing the combined approach with anterior plating alone, significant reductions in C5-C6 motion was noted: 49% in flexion (P <0.05), 48% in extension (P <0.003), and 33% and 39%, respectively, in left and right torsion (P <0.05). Reduction in the left and right lateral bending was not significant (18% and 12%, respectively). The improved fixation had minimal influence on the adjacent segments. CONCLUSIONS: Combined anterior posterior fixation further reduces the segmental motion by almost 50% in flexion and extension, 33% and 39% in torsion, and does not significantly alter intradiscal pressure and spinal motion at adjacent segments.

Aged↗
PubMed2004

Time-lapse tracking of barley androgenesis reveals position-determined cell death within pro-embryos.

Following abiotic stress to induce barley (Hordeum vulgare L.) androgenesis, the development of 794 enlarged microspores in culture was monitored by time-lapse tracking. In total, 11% of the microspores tracked developed into embryo-like structures (type-I pathway), 36% formed multicellular structures (type-II pathway) and 53% of the microspores followed gametophytic divisions, accumulated starch and died in the first days of tracking (type-III pathway). Despite the microspore fate, enlarged microspores showed similar morphologies directly after stress treatment. Ultrastructural analysis, however, revealed two morphologically distinct cell types. Cells with a thin intine layer and an undifferentiated cytoplasm after stress treatment were associated with type-I and type-II pathways, whereas the presence of differentiated amyloplasts and a thick intine layer were associated with the type-III pathway. Tracking revealed that the first morphological change associated with embryogenic potential was a star-like morphology, which was a transitory stage between uninucleate vacuolated microspores after stress and the initiation of cell division. The difference between type-I and type-II pathways was observed during the time they displayed the star-like morphology. During the transition phase, embryo-like structures in the type-I pathway were always released out of the exine wall at the opposite side of the pollen germ pore, whereas in the type-II pathway multicellular structures were unable to break the exine and to release embryo-like structures. Moreover, by combining viability studies with cell tracking, we show that release of embryo-like structures was preceded by a decrease in viability of the cells positioned at the site of exine wall rupture. These cells were also positively stained by Sytox orange, a cell death indicator. Thereby, we demonstrate, for the first time, that a position-determined cell death process marks the transition from a multicellular structure into an embryo-like structure during barley androgenesis.

Cell Death↗
PubMed2004

Synthesis, structures and electrochemical properties of nitro- and amino-functionalized diiron azadithiolates as active site models of Fe-only hydrogenases.

Complex [[(mu-SCH2)2N(4-NO2C6H4)]Fe2(CO)6] (4) was prepared by the reaction of the dianionic intermediate [(mu-S)2Fe2(CO)6](2-) and N,N-bis(chloromethyl)-4-nitroaniline as a biomimetic model of the active site of Fe-only hydrogenase. The reduction of 4 by Pd-C/H2 under a neutral condition afforded complex [[(mu-SCH2)2N(4-NH2C6H4)]Fe2(CO)6] (5) in 67 % yield. Both complexes were characterized by IR, 1H and 13C NMR spectroscopy and MS spectrometry. The molecular structure of 4, as determined by X-ray analysis, has a butterfly 2Fe2S core and the aryl group on the bridged-N atom slants to the Fe(2) site. Cyclic voltammograms of 4 and 5 were studied to evaluate their redox properties. It was found that complex 4 catalyzed electrochemical proton reduction in the presence of acetic acid. A plausible mechanism of the electrocatalytic proton reduction is discussed.

Aza Compounds↗
PubMed2004

Important differentiation of factors that predict outcome in peritoneal dialysis patients with different degrees of residual renal function.

BACKGROUND: Residual renal function (RRF) is an important predictor of outcome in peritoneal dialysis (PD) patients. Whether results from survival studies in dialysis patients with RRF can also be extrapolated to anuric patients remains uncertain. In this observational study, we examined the characteristics of PD patients with a residual glomerular filtration rate (GFR) > or =1 ml/min per 1.73 m2 vs those with complete anuria and differentiated factors that predict outcome in the two groups of patients. METHODS: Two hundred and forty-six continuous ambulatory peritoneal dialysis (CAPD) patients (39% being completely anuric) were recruited from a single regional dialysis centre. Assessments of haemodynamic, echocardiographic, nutritional and biochemical parameters and indices of dialysis adequacy were done at study baseline and were related to outcomes. RESULTS: During the prospective follow-up of 30.8+/-13.8 (mean+/-SD) months, 28.0% of patients with residual GFR > or =1 ml/min per 1.73 m2 vs 50.5% of anuric patients had died (P = 0.005). The overall 2 year patient survival was 89.7 and 65.0% for patients with GFR > or =1 ml/min per 1.73 m2 and anuric patients, respectively (P = 0.0012). Compared with patients with GFR > or =1 ml/min per 1.73 m2, anuric patients were dialysed for longer (P<0.001), were more anaemic (P<0.005), and had higher calcium-phosphorus product (P<0.01), higher C-reactive protein (P<0.001), lower serum albumin (P<0.05), greater prevalence of malnutrition according to subjective global assessment (P<0.05) and more severe cardiac hypertrophy (P<0.001) at baseline. Using multivariable Cox regression analysis, serum albumin, left ventricular mass index and residual GFR were significant factors associated with mortality in patients with GFR > or =1 ml/min per 1.73 m2, while increasing age, atherosclerotic vascular disease and higher C-reactive protein were associated with greater mortality in anuric PD patients. CONCLUSIONS: Our study demonstrates more adverse cardiovascular, inflammatory, nutritional and metabolic profiles as well as higher mortality in anuric PD patients. Furthermore, factors associated with mortality are also not equivalent for PD patients with and without RRF, suggesting that patients with and without RRF are qualitatively different.

Cohort Studies↗
PubMed2004

Carbon-nanotube/copper composite electrodes for capillary electrophoresis microchip detection of carbohydrates.

The preparation of carbon nanotube (CNT)/copper composite electrodes, based on co-mixing CNT and Cu powders within mineral oil, is described. The new composite electrode is used for improved amperometric detection of carbohydrates following their capillary electrophoresis (CE) microchip separations. The CNT/Cu composite electrode detector displays enhanced sensitivity compared to detectors based on copper or CNT alone. The marked catalytic action of the CNT/Cu composite material permits effective low potential (+0.5 V vs. Ag/AgCl) amperometric detection, and is coupled to the renewability, bulk modification and versatility advantages of composite electrodes. The CNT/Cu composite surface also leads to a greater resistance to surface fouling compared to that observed at the copper electrode. Factors affecting the electrocatalytic activity and the CE microchip detection are examined and optimized. The CNT/Cu composite electrode is also shown to be useful for the detection of amino acids as indicated from preliminary results. While the present work has focused on the enhanced CE microchip detection of carbohydrates and amino acids, the CNT/metal-composite electrode route should benefit the detection of other important groups of analytes.

Amino Acids↗