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H Bai

Publications and source records attributed to H Bai.

At least 19 recordsLinked to original sources
PubMed2004

Hand-assisted transperitoneal laparoscopic living donor nephrectomy.

OBJECTIVE: We introduced and evaluated the advantages and disadvantages of the hand-assisted transperitoneal laparoscopic technique for living donor nephrectomy. MATERIALS AND METHODS: In December 2001, we started using the technique of hand-assisted transperitoneal laparoscopic living donor nephrectomy (HLDN) in 10 cases. The procedure utilizes a hand-assisted device to increase safety and control of the laparoscopic technique. RESULTS: Only left nephrectomy was performed. The mean total operating and the warm ischemia times were 130 minutes and 3.0 minutes, respectively. Average lengths of renal artery and vein were 1.95 cm and 2.8 cm, respectively. There were no intraoperative or postoperative complications. CONCLUSIONS: HLDN is an easier procedure than the traditional laparoscopic living donor nephrectomy and can greatly mitigate the learning curve. HLDN has shortened warm ischemia time and operating time. It is also good for trocar placement, prevention of torsion of the kidney, control of potential bleeding at the final stage of vascular stapling, and kidney removal. Therefore, HLDN is a promising method for living donor nephrectomy.

Adult↗
PubMed2004

Purification and characterization of a lipopeptide produced by Bacillus thuringiensis CMB26.

AIMS: To isolate an antagonist for use in the biological control of phytopathogenic fungi including Colletotrichum gloeosporioides, then to purify and characterize the biocontrol agent produced by the antagonist. METHODS AND RESULTS: Bacteria that exhibited antifungal activity against the causative agent pepper anthracnose were isolated from soil, with Bacillus thuringiensis CMB26 showing the strongest activity. A lipopeptide produced by B. thuringiensis CMB26 was precipitated by adjusting the pH 2 with 3 n HCl and extracted using chloroform/methanol (2:1, v/v) and reversed-phase HPLC. The molecular weight was estimated as 1447 Da by MALDI-TOF mass spectrometry. Scanning electron and optical microscopies showed that the lipopeptide has activity against Escherichia coli O157:ac88, larvae of the cabbage white butterfly (Pieris rapae crucivora) and phytopathogenic fungi. The lipopeptide had cyclic structure and the amino acid composition was L-Glu, D-Orn, L-Tyr, D-allo-Thr, D-Ala, D-Val, L-Pro, and L-Ile in a molar ratio of 3:1:2:1:1:2:1:1. The purified lipopeptide showed the same amino acid composition as fengycin, but differed slightly in fatty acid composition, in which the double bond was at carbons 13-14 (m/z 303, 316) and there was no methyl group. CONCLUSION: A lipopeptide was purified and characterized from B. thuringiensis CMB26 and found to be similar to the lipopeptide fengycin. This lipopeptide can function as a biocontrol agent, and exhibits fungicidal, bactericidal, and insecticidal activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Compared with surfactin and iturin, the lipopeptide from B. thuringiensis CMB26 showed stronger antifungal activity against phytopathogenic fungi. This lipopeptide is a candidate for the biocontrol of pathogens in agriculture.

Amino Acids↗
PubMed2003

Hydrogen peroxide mediates higher order chromatin degradation.

Although a large body of evidence supports a causative link between oxidative stress and neurodegeneration, the mechanisms are still elusive. We have recently demonstrated that hydrogen peroxide (H(2)O(2)), the major mediator of oxidative stress triggers higher order chromatin degradation (HOCD), i.e. excision of chromatin loops at the matrix attachment regions (MARs). The present study was designed to determine the specificity of H(2)O(2) in respect to HOCD induction. Rat glioma C6 cells were exposed to H(2)O(2) and other oxidants, and the fragmentation of genomic DNA was assessed by field inversion gel electrophoresis (FIGE). S1 digestion before FIGE was used to detect single strand fragmentation. The exposure of C6 cells to H(2)O(2) induced a rapid and extensive HOCD. Thus, within 30 min, total chromatin was single strandedly digested into 50 kb fragments. Evident HOCD was elicited by H(2)O(2) at concentrations as low as 5 micro M. HOCD was mostly reversible during 4-8h following the removal of H(2)O(2) from the medium indicating an efficient relegation of the chromatin fragments. No HOCD was induced by H(2)O(2) in isolated nuclei indicating that HOCD-endonuclease is activated indirectly by cytoplasmic signal pathways triggered by H(2)O(2). The exposure of cells to a synthetic peroxide, i.e. tert-butyrylhydroperoxide (tBH) also induced HOCD, but to a lesser extent than H(2)O(2). Contrary to the peroxides, the exposure of cells to equitoxic concentration of hypochlorite and spermine NONOate, a nitric oxide generator, failed to induce rapid HOCD. These results indicate that rapid HOCD is not a result of oxidative stress per se, but is rather triggered by signaling cascades initiated specifically by H(2)O(2). Furthermore, the rapid and extensive HOCD was observed in several rat and human cell lines challenged with H(2)O(2), indicating that the process is not restricted to glial cells, but rather represents a general response of cells to H(2)O(2).

Animals↗
PubMed2001

Structure-activity studies for a novel series of bicyclic substituted hexahydrobenz[e]isoindole alpha1A adrenoceptor antagonists as potential agents for the symptomatic treatment of benign prostatic hyperplasia.

In search of a uroselective alpha1A subtype selective antagonist, a novel series of 6-OMe hexahydrobenz[e]isoindoles attached to a bicyclic heterocyclic moiety via a two-carbon linker was synthesized. It was found that in contrast to the previously described series of tricyclic heterocycles,(1) this bicyclic series has very specific requirements for the heterocyclic attachments. The most important structural features contributing to the alpha1A/alpha1B selectivity of these compounds were identified. In vitro functional assays for the alpha1 adrenoceptor subtypes were used to further characterize the most selective compounds, and in vivo models of vascular vs prostatic tone were used to assess uroselectivity. Compound 48 showed the highest degree of selectivity in the radioligand binding assays (56-fold), in the in vitro functional tests (80-fold), and for in vivo prostate selectivity (960-fold).

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2001

Effects of adrenalectomy and hormone replacement on B6C3F1 mice fed a high-fat diet.

Bilateral adrenalectomy (ADX) causes decreased circulating leptin in both obese and lean mice. It remains unclear whether the decreased plasma leptin after ADX is due to decreased adipose tissue or is due to decreased circulating glucocorticoids. The present experiment was performed to test the hypothesis that the absence of glucocorticoids from circulation is sufficient to decrease circulating leptin. Sixty-four adult male B6C3F1 mice were individually housed and fed either Purina rat chow or an experimental diet. After 6 weeks, mice fed the experimental diet gained more weight than mice fed the control diet. Each dietary group was then subdivided into four groups: ADX with cholesterol replacement (ADX-CHOL), ADX with corticosterone (CORT) replacement (ADX+CORT), ADX with aldosterone (ALDO) replacement (ADX+ALDO), and sham operation (SHAM). Two days after surgery, mice were killed and exsanguinated and the carcasses were prepared for gravimetric analyses. Blood was collected and centrifuged and the plasma was assayed for leptin, CORT, and ALDO. Blood glucose was determined using whole blood taken before centrifugation. There was no difference in body weight due to ADX after 2 days. Mice fed the experimental diet had higher circulating leptin than those fed the control diet. The ADX+CORT groups (both experimental and control diets) had higher plasma leptin concentrations than the other groups. No differences were observed between ADX-CHOL and SHAM groups. These results suggest that circulating leptin is not directly controlled by glucocorticoids. The effect of ADX on circulating leptin reported by others may be the consequence of decreased adiposity.

Adrenal Cortex Hormones↗
PubMed2001

Higher order chromatin degradation in glial cells: the role of calcium.

Higher order chromatin degradation (HOCD), i.e. the scission of nuclear chromatin loops at the matrix attachment regions (MARs), is a hallmark of programmed cell death. We have previously demonstrated that hydrogen peroxide (H(2)O(2)) induces rapid HOCD in cultured oligodendrocytes generating two subpopulations of DNA fragments of >or=400 and 50-200 kb. In the present study, we examined the involvement of calcium in this process. HOCD was induced in primary rat oligodendrocytes by exposure to 1 mM H(2)O(2) and assessed by field inversion gel electrophoresis with and without S1 endonuclease digestion, to detect single and double stranded fragmentation, respectively. Chelating intracellular calcium with BAPTA/AM prior to H(2)O(2) exposure inhibited HOCD in a dose-dependent manner. Complete inhibition of HOCD was attained with 50 muM BAPTA/AM. The pretreatment of cells with desferroxamine mesylate, which may lower intracellular calcium levels, also resulted in a profound inhibition of HOCD, but the initial chromatin digestion into >or=400 kb single stranded DNA fragments was unaffected. Neither removing extracellular calcium nor blocking calcium release from intracellular stores with TMB-8 affected HOCD. Moreover, increasing intracellular calcium with A23187 calcium ionophore did not induce HOCD. Subsequent study in nuclei purified from C6 glioma cells revealed that the endonuclease responsible for HOCD is calcium-independent, but is magnesium-dependent. Magnesium-induced HOCD was not affected by the removal of calcium from nuclei with EGTA, but was practically abrogated in nuclei prepared from BAPTA/AM-pretreated cells. These results indicate that although H(2)O(2)-induced HOCD is not directly mediated by an increase of intracellular calcium concentration, normal resting levels of intracellular calcium are required for the maintenance of MAR-associated endonuclease in an active form.

Animals↗
PubMed2001

Medial axis reformation: a new visualization method for CT angiography.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate a new method (medial axis reformation [MAR]) for visualizing three-dimensional vascular data at electron-beam computed tomographic (CT) angiography. MATERIALS AND METHODS: MAR was performed automatically with a personal computer-based workstation. After the region of interest was edited, voxels were divided into groups according to their path lengths. Centroids of groups were connected to form the medial axis. Then, the medial axis was refined with multiscale medial response. Bifurcations were also detected and refined. Finally, curved sections were generated through the branches and laid out onto a single image by using a splitting method. The authors performed MAR during electron-beam CT angiography of coronary arteries, common carotid arteries, and iliac arteries. RESULTS: MAR displayed curved sections of branched vessels on one image, cut through the axis of vessels to show the vessel diameter objectively, and allowed the viewing direction to be altered arbitrarily. CONCLUSION: Results of preliminary applications demonstrate that MAR is a valuable new visualization method for CT angiography.

Adult↗
PubMed2001

Effects of window and threshold levels on the accuracy of three-dimensional rendering techniques in coronary artery electron-beam CT angiography.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the effect of window level and gray-scale threshold on the demonstration of coronary artery lumina at three-dimensional electron-beam computed tomographic (CT) angiography. MATERIALS AND METHODS: Forty-four coronary artery branches in postmortem pigs were evaluated with electron-beam CT angiography, and the findings were compared with those from conventional angiography. Images from electron-beam CT angiography were reconstructed with maximal intensity projection (MIP), multiplanar reformation (MPR), and shaded-surface display (SSD). Four categories of window level and gray-scale threshold were evaluated. RESULTS: Three-dimensional electron-beam CT angiography accurately depicted the luminal diameters of the coronary arteries compared with conventional angiography (r = 0.83-0.90, P < .0001). The length of lumina visualized at electron-beam CT angiography was significantly shorter than that visualized with conventional angiography (P < .001). The use of MPR enabled visualization of longer segments of coronary arteries than did the use of MIP or SSD (P < .05). The higher the window level and gray-scale threshold used, the smaller the coronary luminal diameters measured (P < .05). The most accurate window level and gray-scale threshold (82.6 HU +/- 29.8 and 89.5 HU +/- 29.7, respectively) were found to correspond to the attenuation of the lumina (275.8 HU +/- 58.8). Results of simple linear regression showed a strong correlation between luminal attenuation and window level (r = 0.89, P < .0001) or gray-scale threshold (r = 0.95, P < .0001). CONCLUSION: Electron-beam CT angiography shows promise in the visualization of coronary artery lumina. For accurate display of lumina, a proper window level and gray-scale threshold for three-dimensional rendering techniques should be determined and used on the basis of the attenuation of the target vessel.

Animals↗
PubMed2001

Optimal electrocardiographically triggered phase for reducing motion artifact at electron-beam CT in the coronary artery.

RATIONALE AND OBJECTIVES: The authors performed this study to (a) investigate coronary movement with electron-beam computed tomography (CT) and (b) find the optimal electrocardiographic (ECG) triggering phase for eliminating motion artifact. MATERIALS AND METHODS: One hundred fifty-one patients without arrhythmia were examined with electron-beam CT. First, movie scans were obtained to create displacement and velocity graphs of coronary artery movement. Then, a volume scan with an exposure time of 100 msec was obtained with various ECG trigger settings. RESULTS: Movement patterns of coronary arteries varied with heart rate. Optimal triggering phase was before atrial systole (near 71% of the R-R interval) when heart rate was slower than 68 beats per minute and at ventricular end systole when heart rate was fast. Rate of severe motion artifacts decreased from 43% to 0% when triggering was altered from 80% of the R-R interval to the individual optimal value. Experimental values of the optimal phase at different heart rates were derived, and severe motion artifact was only 3.0% with these values. CONCLUSION: ECG triggering set according to the heart rate enables a great reduction in motion artifacts at electron-beam CT with a 100-msec exposure time. The results may have implications for magnetic resonance imaging of the coronary artery.

Adult↗
PubMed2001

Biotreatment of hydrogen sulfide- and ammonia-containing waste gases by fluidized bed bioreactor.

Gas mixtures of H2S and NH3 are the focus of this study of research concerning gases generated from animal husbandry and treatments of anaerobic wastewater lagoons. A heterotrophic microflora (a mixture of Pseudomonas putida for H2S and Arthrobacter oxydans for NH3) was immobilized with Ca-alginate and packed into a fluidized bed reactor to simultaneously decompose H2S and NH3. This bioreactor was continuously supplied with H2S and NH3 separately or together at various ratios. The removal efficiency, removal rate, and metabolic product of the bioreactor were studied. The results showed that the efficiency remained above 95% when the inlet H2S concentration was below 30 ppm at 36 L/hr. Furthermore, the apparent maximum removal and the apparent half-saturation constant were 7.0 x 10(-8) g-S/cell/day and 76.2 ppm, respectively, in this study. The element sulfur as a main product prevented acidification of the biofilter, which maintained the stability of the operation. As for NH3, the greater than 90% removal rate was achieved as long as the inlet concentration was controlled below 100 ppm at a flow rate of 27 L/hr. In the NH3 inlet, the apparent maximum removal and the apparent half-saturation constant were 1.88 x 10(-6) g-N/cell/day and 30.5 ppm, respectively. Kinetic analysis showed that 60 ppm of NH3 significantly suppressed the H2S removal by Pseudomonas putida, but H2S in the range of 5-60 ppm did not affect NH3 removal by Arthrobacter oxydans. Results from bioaerosol analysis in the bioreactor suggest that the co-immobilized cell technique applied for gas removal creates less environmental impact.

Ammonia↗
PubMed2001

Malignant solitary fibrous tumor of the pleura with liposarcomatous differentiation.

Pleural solitary fibrous tumors (SFTs) are uncommon tumors. Although these tumors have been well characterized, malignant pleural SFTs with liposarcomatous differentiation have not been reported. We report an unusual malignant pleural SFT intermixed with foci of well-differentiated liposarcoma. The patient was a 66-year-old, white man with a large, solid right pleural mass that measured 13.5 x 10.3 x 8.5 cm. The tumor was composed of spindle-shaped and plump cells embedded in dense collagenous stroma. The tumor cells were arranged in interlacing fascicles or in a patternless pattern. Marked nuclear atypia, a high mitotic rate (21 mitoses per 10 high-power fields), and areas of prominent necrosis were evident. In addition, numerous adipocytes mixed with typical lipoblasts were seen scattered throughout portions of the tumor. Immunohistochemistry revealed the tumor cells were strongly positive for CD34 and vimentin and negative for cytokeratin, desmin, smooth muscle actin (IA4), and S100. To the best of our knowledge, this case represents the first example of a malignant SFT with liposarcomatous differentiation.

Aged↗
PubMed2001

[Study on apoE gene polymorphism in Chinese endogenous hypertriglyceridemia].

OBJECTIVE: To investigate apolipoprotein(apo) E polymorphism and its relationship with serum lipids and apolipoproteins in Chinese patients with endogenous hypertriglyceridemia(HTG). METHODS: apoE genotype was assayed by polymerase chain reaction- restriction fragment length polymorphism(PCR-RFLP), serum lipids were determined by enzyme method, and apolipoproteins were measured by radial immunodiffusion assay in 225 endogenous HTG patients whose fasting serum TG levels were > or = 2.26 mmol/L and in 230 healthy subjects whose fasting serum lipids levels were TG<1.82 mmol/L, TC<6.21 mmol/L from a population of Chinese Han nationality in Chengdu area. RESULTS: Compared with the controls, the values of BMI, TG, TC, nHDLC, apoB100, CII, CIII, E and TG/HDLC in HTG patients were significantly increased and the values of HDLC, apoAI and apoE/apoCIII were significantly decreased(P<0.001). apoE3/3 genotype and allele epsilon(3) frequency in HTG group and the control group were both the highest, and allele epsilon( 2) frequency in HTG group tended to increase than that in the control group(P>0.05). Both in HTG group and control group, the genotype of apoE2 had higher serum TG and apoE levels, lower LDLC level and decreased apoE/apoCIII ratio as compared with the genotype of apoE3 or apoE4(P<0.001). CONCLUSION: Allele epsilon(2) of apoE gene was associated with higher serum TG and apoE levels and lower serum LDLC level, and the lower ratio of apoE/apoCIII was associated with the higher serum level of TG in endogenous HTG.

Adult↗
PubMed2001

[Analysis of apoA IV gene VNTR polymorphism in Chinese endogenous hypertriglyceridemics].

OBJECTIVE: To search the variation of apoA IV gene and its relation to endogenous hypertriglyceridemia (HTG) in Chinese population. METHODS: Forty- seven endogenous hypertriglyceridemics and 48 healthy subjects from a population of Chinese Han nationality in Chengdu area were studied using sequencing of apoA IV gene amplified by polymerase chain reaction (PCR). RESULTS: The frequency of (CTGT)(3) allele in Chinese control group was significantly different from that reported in German Caucasians (0.253 vs 0.607, P<0.01) and in Italian Caucasians (0.253 vs 0.522, P<0.01), but not different from that reported in Japanese (0.253 vs 0.262, P>0.05). The frequency of (CTGT)(3) allele showed no significant difference between normal control and HTG groups(0.223 vs 0.281,P>0.05). In the healthy control group, the subjects with genotype 3/3 of VNTR site had a higher serum mean concentration of LDLC as compared to those with genotype 3/4 (3.698 +/- 0.67 mmol/L vs 2.974 +/- 0.54 mmol/L, P<0.05). CONCLUSION: The results suggest that VNTR polymorphism in apoA IV gene is associated with healthy control subjects to some extent in Chinese population.

Adult↗
PubMed2001

Down-regulation of four arsenic antagonists on apoptosis and telomerase activity induced by arsenic trioxide in three myelocytic leukemia cell lines.

AIM: To investigate regulative effects of thiol reagents, N-acetyl-l-cysteine (NAC) and natrii dimercaptosussinas (NDMS), catalase (CAT), and calcium chelator 2-[(2-bis-[carboxymethyl]-amino-5-methyl-phenoxy)-met]-6-methoxy-8-bis-[carboxy-methyl]-aminoquinoline (Quin 2) on apoptosis and telomerase activity induced by arsenic trioxide (As2O3) in three myelocytic leukemia cell lines. METHODS: Flow cytometry was used to examine apoptosis and a PCR ELISA kit was used to detect telomerase activity. RESULTS: As2O3 induced about 40 % - 60 % of apoptosis in NB4, K562, and HL-60 cells at the concentration of 0.6, 2.7, and 8.1 micromol/L respectively, as well as down-regulated telomerase activities in three cell lines. NAC 4 mmol/L, NDMS 200 micromol/L, CAT 80 kU/L, and Quin 2 20 micromol/L could down-regulate apoptosis variously induced by As2O3. NAC and CAT alone could decline telomerase activity in three cell lines and further decline telomerase activities that had been decreased by As2O3, whereas Quin 2 antagonized the decline in K562 and HL-60 cells. CONCLUSION: Thiol activity loss, free radical alteration, intracellular calcium changes, and decline of telomerase activity might be involved in As2O3-induced apoptosis. NAC, NDMS, CAT, and Quin 2 antagonized in some extent the effect of As2O3 on the three tested cell lines.

Acetylcysteine↗
PubMed2001

Evaluation of coronary artery bypass graft patency using three-dimensional reconstruction and flow study of electron beam tomography.

OBJECTIVE: To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT). METHODS: Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis. RESULTS: There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5%) of 135 arterial grafts were patent, and 345 (77.7%) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P < 0.001). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7%, 94.1% and 96.7%, respectively) than did EBT flow study (88.4%, 82.4% and 85.2%, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 +/- 2.2 ml.min-1.g-1 and 6.9 +/- 2.8 ml.min-1.g-1, respectively (P < 0.001). CONCLUSION: The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.

Adult↗
PubMed2001

[Changes in Galphaq/11 mediated signal transduction pathway in the aorta of two kidney one clip hypertensive rats].

The objective of this study was to investigate the role of signal transduction pathway mediated by Galphaq/11 of the aorta in blood pressure regulation during the development of two-kidney one clip (2K1C) Glodblatt hypertension in the rat. Levels of Galphaq/11-subunit and extracellular signal regulated kinase 1/2 (ERK1/2) of the aorta were measured by Western blot analysis at week 1, 2, 4 or 8 after operation. Phospholipase C (PLC) activity of the aorta was measured by using (3)H phosphatidylinostol (4,5) bisphosphate as a substrate. Both systolic and diastolic blood pressure increased markedly in 2K1C rats at week 2, 4 or 8, whereas, the increase in Galphaq/11 and ERK1/2 expression of the aorta began at week 1 after operation (increased by 57.53% and 40.16%, respectively), and maintained at a high level during week 2 8 compared with time matched controls (P<0.01). PLC activities in the aorta were also increased significantly in 2K1C groups at week 4 and 8 compared with the time matched controls (P<0.05). The results indicate that Galphaq/11-mediated signal transduction pathway of the aorta is activated in 2K1C hypertension, and may contribute to the initiation and maintenance of renal hypertension.

Animals↗