Peptidergic regulation of plasminogen activator inhibitor-1 gene expression in vivo

BACKGROUND

The mechanisms by which PAI-1 biosynthesis is altered during stress have not been fully elucidated. Studies suggest a major role for neuro-peptidergic modulation of the stress response by PACAP (pituitary adenylate cyclase-activating polypeptide), a member of the VIP/secretin/glucagon family.

OBJECTIVE

We tested the hypothesis that PACAP regulates PAI-1 biosynthesis during stress in vivo.

METHODS

PAI-1 gene expression was monitored by RT-PCR in adrenal glands harvested from C57BL/6J mice that were unstressed, or subjected to restraint stress for 2 h, or treated with PACAP.

RESULTS

PAI-1 mRNA expression was markedly increased in adrenals from stressed mice. Restraint stress resulted in much smaller increments in adrenal tPA mRNA, suggesting that local adrenal tPA/PAI-1 biosynthetic balance is markedly altered by stress. The observed increases in PAI-1mRNA during stress were substantially blunted (55 ± 4%, P < 0.001) by pretreatment with the specific PACAP receptor antagonist, PACAP6-38, compared with pretreatment with vehicle. Administration of the agonist PACAP1-38 alone resulted in a dose-dependent increase in tissue PAI-1 mRNA. PACAP1-38 administration also resulted in substantial increases in plasma PAI-1 antigen and active PAI-1 concentrations that were significantly greater in male mice than in female mice.

CONCLUSIONS

We conclude that adrenal PAI-1 mRNA expression is markedly increased by stress, and that the PACAP peptidergic signaling pathway plays a major role in mediating the stress-induced increase in PAI-1 biosynthesis.

Regulation of decidualization in human endometrial stromal cells through exchange protein directly activated by cyclic AMP (Epac)

INTRODUCTION

Human endometrial stromal cells (ESCs) undergo differentiation during the decidualization process. Decidualization is characterized by their enhanced production of IGF binding protein-1 (IGFBP-1), prolactin (PRL), and the forkhead transcriptional factor FOXO1, and transformation into more rounded cells, during the secretory phase of the menstrual cycle and subsequent pregnancy. Protein kinase A (PKA)-mediated cAMP signaling is crucial for this process. The present study was undertaken to examine the involvement of a mediator of cAMP signaling, exchange protein directly activated by cAMP (Epac), in decidualization of cultured ESCs.

RESULTS

Treatment of ESCs with the Epac-selective cAMP analog 8-CPT-2-OMe-cAMP (CPT) had no effect on IGFBP-1, PRL, and FOXO1 mRNA expression. However, CPT potentiated IGFBP-1 and PRL expression stimulated by the PKA-selective cAMP analog N(6)-Phe-cAMP (Phe) and activated Rap1, a downstream regulator of Epac signaling. Knock-down of Epac1, Epac2, or Rap1 significantly inhibited the Phe- or Phe/CPT-induced increase in IGFBP-1 and PRL expression, as well as Rap1 activation. Furthermore, CPT enhanced IGFBP-1 and PRL expression and the morphological differentiation induced by ovarian steroids, whereas Epac1, Epac2, or Rap1 knock-down suppressed these events.

CONCLUSION

These data provide evidence for the involvement of the Epac/Rap1 signaling pathway in cAMP-mediated decidualization of human ESCs.

Identification and expression analysis of components involved in rice Xa21-mediated disease resistance signalling

Rice Xa21 gene encodes a receptor-like kinase that confers broad-spectrum resistance against Xanthomonas oryzae pv. oryzae (Xoo). Recently, a number of genes involved in the Xa21-mediated disease resistance pathway have been identified. Based on our previous data and the literature, we chose 16 candidate proteins and made corresponding antibodies. Using Western blotting, we systematically investigated the expression profile of the proteins in Xa21-mediated disease resistance response. We found nine proteins with altered expression. We further compared their expression in resistance, susceptible and mock responses, and found that GST expression was up-regulated during the resistance process, indicating GST is a positive regulator in resistance responses. ATPsB expression was down-regulated during both the resistance and susceptible response processes, although it was higher in the resistance response than that in the susceptible response. The total amount of MYB, GAPDH, CatB, Trx and NB-ARC proteins was lower in the resistance than in the susceptible response, but their abundance per unit bacteria in the resistance response was still higher than in the susceptible response, suggesting that these proteins might be positive regulators in the resistance response. In addition, expression of another ERF was induced by inoculation with bacterial blight pathogen, and expression of Zf-LSD1 was activated by wounding stress alone. Interestingly, most proteins showed similar altered expression patterns in the resistance and susceptible responses, but differed to some extents, implying that both responses might share common molecular mechanisms. This study revealed evidence of resistance-related protein expression, providing a foundation for better understanding of their functions.

Thermodynamic estimation of minor element distribution between immiscible liquids in Fe-Cu-based metal phase generated in melting treatment of municipal solid wastes

Waste electrical and electronic equipment (WEEE) has become an important target in managing material cycles from the viewpoint of not only waste management and control of environmental pollution but also resource conservation. This study investigated the distribution tendency of trace elements in municipal solid waste (MSW) or incinerator ash, including valuable non-ferrous metals (Ni, Co, Cr, Mn, Mo, Ti, V, W, Zr), precious group metals (PGMs) originated from WEEE (Ag, Au, Pd, Pt), and others (Al, B, Pb, Si), between Fe-rich and Cu-rich metal phases by means of simple thermodynamic calculations. Most of the typical alloying elements for steel (Co, Cr, Mo, Nb, Ni, Si, Ti, V, and W) and Rh were preferentially distributed into the Fe-rich phase. PGMs, such as Au, Ag, and Pd, were enriched in the Cu-rich phase, whereas Pt was almost equally distributed into both phases. Since the primary metallurgical processing of Cu is followed by an electrolysis for refining, and since PGMs in crude copper have been industrially recovered from the resulting anode slime, our results indicated that Ag, Au, and Pd could be effectively recovered from MSW if the Cu-rich phase could be selectively collected.

Class A scavenger receptor promotes cerebral ischemic injury by pivoting microglia/macrophage polarization

Class A scavenger receptor (SR-A) is primarily expressed in microglia/macrophages and plays an important role in immune responses. However, whether SR-A can influence microglia/macrophage polarization in cerebral ischemic injury is not known. To this end we monitored the phenotypic alteration of microglia/macrophages in an animal model of cerebral ischemia injury. SR-A was up-regulated in mouse brains 24h after permanent occlusion of middle cerebral artery (MCAO). SR-A-deficient mice displayed reduced infarct size and improved neurological function compared with wild-type mice littermate controls. Furthermore, a decrease in inflammatory F4/80(+)CD11b(+)CD45(high)CD11c(+) microglia/macrophages and attenuated nuclear factor-kappaB (NF-κB) activation was found in ischemic brains in the SR-A null mice. This was accompanied by alleviation of classically activated M1 macrophage markers and preservation of alternatively activated M2 macrophage markers. These data suggest that SR-A contributes to cerebral ischemic injury by pivoting the phenotype of microglia/macrophages to a skewed M1 polarization.

Selenoprotein dSelK in Drosophila elevates release of Ca2+ from endoplasmic reticulum by upregulating expression of inositol 1,4,5-tris-phosphate receptor

dSelK (G-rich), a homolog of human and mouse SelK, is one of three selenoproteins in Drosophila melanogaster. It is the only trans-membrane selenoprotein in D. melanogaster integrated into both the endoplasmic reticulum (ER) membrane and the Golgi apparatus. The gene expression profile of Drosophila Schneider 2 (S2) cells after the dsRNA interference (dsRNAi) targeting of dSelK was examined with the GeneChip Drosophila Genome 2.0 Array (Affymetrix), a high-density oligonucleotide microarray encompassing nearly the full Drosophila genome. The results showed that the transcriptional expression of eight genes whose proteins are located on (or related to) the ER or the Golgi apparatus was highly induced or repressed by the dsRNAi treatment. The mRNA levels of the inositol 1,4,5-tris-phosphate receptor (IP3 receptor), whose gene product is integrated into the ER membrane and regulates the release of Ca2+ from the ER to the cytosol, were significantly downregulated. In contrast, the expression of inositol 1,4,5-tris-phosphate kinase 1, which is a cytosolic protein with opposing functions to the IP3 receptor, was significantly upregulated. Quantitative real-time PCR verified these results. The concentration of intracellular free Ca2+ of the Drosophila S2 cells was significantly decreased after the knockdown of dSelK, whereas overexpression of dSelK significantly increased the intracellular free Ca2+ concentration. These results indicate that dSelK in D. melanogaster is involved in regulating the release of Ca2+ from the ER to the cytosol and may play important roles in the signal transduction pathways involving Ca2+ mobilization.

Wld(S) protects against peripheral neuropathy and retinopathy in an experimental model of diabetes in mice

AIMS/HYPOTHESIS

We aimed to evaluate the effect of the mutant Wld(S) (slow Wallerian degeneration; also known as Wld) gene in experimental diabetes on early experimental peripheral diabetic neuropathy and diabetic retinopathy.

METHODS

The experiments were performed in four groups of mice: wild-type (WT), streptozotocin (STZ)-induced diabetic WT, C57BL/Wld(S) and STZ-induced diabetic C57BL/Wld(S). In each group, intraperitoneal glucose and insulin tolerance tests were performed; blood glucose, glycated haemoglobin and serum insulin were monitored. These mice were also subjected to the following behavioural tests: grasping test, hot-plate test and von Frey aesthesiometer test. For some animals, sciatic-tibial motor nerve conduction velocity, tail sensory nerve conduction velocity and eye pattern electroretinogram were measured. At the end of the experiments, islets were isolated to detect glucose-stimulated insulin secretion, ATP content and extent of apoptosis. The NAD/NADH ratio in islets and retinas was evaluated. Surviving retinal ganglion cells were estimated by immunohistochemistry.

RESULTS

We found that the Wld(S) gene is expressed in islets and protects beta cells against multiple low doses of STZ by increasing the NAD/NADH ratio, maintaining the ATP concentration, and reducing apoptosis. Consistently, significantly higher insulin concentrations, lower blood glucose concentrations, and better glucose tolerance were observed in Wld(S) mice compared with WT mice after STZ treatment. Furthermore, Wld(S) alleviated abnormal sensory responses, nerve conduction, retina dysfunction and reduction of surviving retinal ganglion cells in STZ-induced diabetic models.

CONCLUSIONS/INTERPRETATION

We provide the first evidence that expression of the Wld(S) gene decreases beta cell destruction and preserves islet function in STZ-induced diabetes, thus revealing a novel protective strategy for diabetic models.

Consistency between K-ras mutation in peripheral blood and matched tumor tissues detected by PCR-RFLP in Chinese patients with advanced NSCLC and its clinical significance analysis

8090

Background: To explore the consistency between K-ras mutation in peripheral blood and matched tumor tissues detected by PCR-RFLP and analyze the prognostic effects of K-ras mutation in peripheral blood in Chinese NSCLC patients (pts) treated by epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). Methods: Plasma free DNA and matched tumor samples were collected from 264 hospitalized pts in Department of Thoracic Oncology, Peking University School of Oncology between Jan 2005 and Feb 2008. K-ras mutations were detected in coden 12 and 13 of exon 1 by PCR-RFLP and then verificated by sequencing. We compared the mutations in plasma samples and matched tumor tissues which determined an association between K-ras mutation status and clinical outcomes. Results: In 264 pts, K-ras mutation rates in codon 12 and 13 of exons 1 in peripheral blood were 11.36% (30/264) and 0.75% (2/264), also 9.84% (26/264) and 1.13% (3/264) in matched tumor tissues, respectively. Consistency of mutation in codon 12 between in tissues and plasma was 94%(248/264) (Kappa=0.686,P<0.001). Among 107 pts who received EGFR-TKIs treatment, the effective rate(RR), progression-free survival (PFS) and median survival time (MST) in pts with K-ras mutation in plasma DNA were 6.7.%, 2.7 months and 20.5 months, respectively, all which were lower than those of pts with wild type K-ras (32.5%, 23.7 months, 31.5 months; P=0.001, P=0.001, P=0.278, respectively). Conclusions: There is a high consistency of K-ras mutation rate between plasma DNA and matched tumor tissues. K-ras mutation in plasma is able to predict both response and PFS of NSCLC pts with EGFR-TKIs treatment.

No significant financial relationships to disclose.

Association of plasma EGFR mutations with response to first-line chemotherapy and prognosis in Chinese patients with advanced non-small cell lung cancer

e19017

Background: To investigate associations of plasma EGFR mutations of advanced non-small cell lung cancer (NSCLC) patients with response to the first-line chemotherapy and prognosis. Methods: Plasma EGFR mutations from 145 chemotherapy-naive patients with advanced or metastatic NSCLC were examined by using denaturing high- performance liquid chromatography (DHPLC), and associations of EGFR mutations with tumor response to chemotherapy and clinical outcomes were evaluated. Results: 37.2% (54/145) of the patients was detected to have EGFR mutations in their plasma DNA. The response rate of mutated EGFR carriers to the chemotherapy was 37% (20/54), similar to that of 31.9% (29/91) of wild-type EGFR carriers to the chemotherapy (P= 0.323). Stage IV NSCLC patients with mutated EGFR had a longer PFS than those with wild-type EGFR (4 vs 3 months, P=0.043) after the first-line chemotherapy. The median survival time and 1-, 2- year survival rate for the patients with EGFR mutations (24 months and 85.7%,43.7%) were increased than those with wild-type EGFR (18 months and 65.7%,25.9%) (p=0.0468). Cox multivariate regression analysis showed that clinical stage (IV vs IIIb), response to the first-line chemotherapy (PR vs PD), and EGFR mutations were independent prognostic factors (P=0.008, 0.000 and 0.000 respectively). Conclusions: We conclude that plasma EGFR mutations in the Chinese patients with advanced NSCLC were not associated with response to the first-line chemotherapy, but Stage IV NSCLC patients with mutated EGFR had a longer PFS after the chemotherapy.

No significant financial relationships to disclose.

Effects of immediate compared with delayed gefitinib after front-line chemotherapy in Chinese with advanced non-small cell lung cancer

8069

Background: To compare therapeutic effects of immediate vs. delayed gefitinib used for advanced non-small cell lung cancer (NSCLC) patients who obtained disease control (DC) after front-line chemotherapy in Chinese population. Methods: The study included 121 Chinese with advanced NSCLC treated with standard chemotherapy and obtained DC followed by either immediate gefitinib (66 cases) or delayed gefitinib, i.e. when tumors progressed (55 cases). The disease control rate (DCR), median progression-free survival time (PFS), median overall survival time (OS) of the two groups were analyzed. The impact of EGFR mutation status on the treatments was also evaluated. Results: The median PFS of patients treated in the immediate treatment setting was significantly longer than that of patients without gefitinib treatment (15.23 months versus 8.13 months,P<0.001). However, the overall median PFS was similar in patients treated with either immediate or delayed settings (15.23 months and 16.23 months respectively, P=0.450). There was no significant difference in OS between the two groups. Although patients whose tumors had EGFR mutation showed a longer median PFS compared to those without the mutation in both treatment groups, similar overall PFS was observed between the groups for patients with EGFR mutation (18.75 months and 18.30 months for maintenance and second-line groups, respectively). Conclusions: Immediate gefitinib use may improve PFS for Chinese patients with advanced NSCLC after front-line chemotherapy. However, similar PFS may be achieved by delayed use of gefitinib.

No significant financial relationships to disclose.

A preliminary study on investigating the attachment of soft tissue onto micro-arc oxidized titanium alloy implants

Intraosseous transcutaneous amputation prostheses (ITAP) rely on the integrity of the soft tissue-implant interface as a barrier to exogenous agents, and in the prevention of avulsion and marsupilization. This experimental work aimed at the in vivo evaluation of soft tissue attachment to Ti alloy (Ti6Al4V) transcutaneous custom-made screws treated by a micro-arc oxidation (MAO) method. Prior to implantation, the surface of the MAO treated implants was analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). The experimental model comprised implantation of 16 transcutaneous screws (two groups: MAO and machined (control); total eight implants/group) in the medial aspect of the left tibia of eight female goats. The animals were euthanized at eight weeks and the samples harvested and processed for histological and histomorphometrical analysis of soft tissue attachment to the implant surface. Significant higher soft tissue attachment was observed in the MAO-modified group compared to the control. The in vivo data indicated that MAO-modified Ti alloy could be a useful biomaterial for tissue engineering and benefit applications where bone-anchored transcutaneous implants are used.

Effect of therapeutic immunization using Ad5/35 and MVA vectors on SIV infection of rhesus monkeys undergoing antiretroviral therapy

Antiretroviral therapy (ART) effectively slows the progression of AIDS. However, drug resistance and/or toxicity can limit the utility of ART in many patients. In this study, we assessed whether a viral vector-based vaccine can be used as a therapeutic vaccine in simian immunodeficiency virus (SIV)-infected monkeys. The effect of vaccinating SIVmac239-infected rhesus monkeys with an SIV gag and gp120-expressing adenovirus (Ad) vector vaccine and a modified vaccinia Ankara (MVA) vaccine was explored while being treated with ART. Rhesus monkeys were intravenously infected with 10 and 1000 TCID(50) (50% tissue culture infectious dose) of SIVmac239. Two months after SIV infection, the monkeys received a 4-month treatment with ART. Some of the monkeys were immunized with adenovirus-based vaccine and MVA-based vaccine with 2 months interval during ART. Viral load, CD4 count and SIV-specific immune responses were observed for 7 months after interruption of ART. The vaccinated animals had higher (i) CD4 counts, (ii) SIV-specific cell-mediated immune responses and (iii) anti-SIV-neutralizing antibody (Ab) titers than monkeys treated with ART alone. More importantly, the vaccination significantly reduced the SIV RNA load from animals infected with a low dose of SIV (10 TCID(50)). The anti-SIV cell-mediated and humoral responses induced by the vaccination was inversely correlated with a reduction in SIV viral load and positively correlated with an increase in CD4(+) T cell counts. These results suggest that vaccination can improve antiviral cell-mediated and humoral immunity, which may contribute to controlling viral replication.

Transcription factor broad suppresses precocious development of adult structures during larval-pupal metamorphosis in the red flour beetle, Tribolium castaneum

Broad (br), a transcription factor containing the Broad-Tramtrack-Bric-a-brac (BTB) and zinc finger domains was shown to mediate 20-hydroxyecdysone (20E) action and pupal development in Drosophila melanogaster and Manduca sexta. We determined the key roles of br during larval-pupal metamorphosis using RNA interference (RNAi) in a coleopteran insect, Tribolium castaneum. Two major peaks of T. castaneum broad (Tcbr) mRNA, one peak at the end of feeding stage prior to the larvae entering the quiescent stage and another peak during the quiescent stage were detected in the whole body and midgut tissue dissected from staged insects. Expression of br during the final instar larval stage is essential for successful larval-pupal metamorphosis, because, RNAi-mediated knock-down of Tcbr during this stage derailed larval-pupal metamorphosis and produced insects that showed larval, pupal and adult structures. Tcbr dsRNA injected into the final instar larvae caused reduction in the mRNA levels of genes known to be involved in 20E action (EcRA, E74 and E75B). Tcbr dsRNA injected into the final instar larvae also caused an increase in the mRNA levels of JH-response genes (JHE and Kr-h1b). Knock-down of Tcbr expression also affected 20E-mediated remodeling of midgut during larval-pupal metamorphosis. These data suggest that the expression of Tcbr during the final instar larval stage promotes pupal program while suppressing the larval and adult programs ensuring a transitory pupal stage in holometabolous insects.

Directing human embryonic stem cells to generate vascular progenitor cells

Pluripotent human embryonic stem cells (hESCs) differentiate into most of the cell types of the adult human body, including vascular cells. Vascular cells, such as endothelial cells and vascular smooth muscle cells (SMCs) are significant contributors to tissue repair and regeneration. In addition to their potential applications for treatment of vascular diseases and stimulation of ischemic tissue growth, it is also possible that endothelial cells and SMCs derived from hESCs can be used to engineer artificial vessels to repair damaged vessels and form vessel networks in engineered tissues. Here we review the current status of directing hESCs to differentiate to vascular cells.

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.

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.

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).

[The MRI diagnosis of aortic dissection]

OBJECTIVE

To analyze and address the MRI manifestations and diagnostic importance of aortic dissection.

METHODS

The MRI manifestations in 31 cases of aortic dissection were analyzed retrospectively. Sixteen cases were proved by operation and pathology.

RESULTS

MRI depicted an intimal flap and a double lumen in all 31 patients. The site of intimal tear was located in 7 cases. Also demonstrated were the complications: aortic dilation in 15 cases, aortic branches involvement in 5, thrombus formation in the false lumen in 5, aortic regurgitation in 10, left ventricle hypertrophy in 10, and leak into thorax in 2.

CONCLUSION

As a non-invading imaging method, MRI can demonstrate the site, range and complications of aortic dissection; it is very valuable in the diagnosis of aortic dissection.

[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.

[Spiral CT study of superior vena cava syndrome: correlation between collateral pathways and obstruction site and degree]

BACKGROUND

To study the collateral pathways of superior vena cava syndrome ( SVCS) .

METHODS

Thirty-one spiral CT phlebograms of patients with SVCS were obtained. Superior vena cava was divided into upper and lower segment by azygos arch, and the collateral pathways were divided into anterior and posterior groups according to their sites in the chest wall. The distribution of collateral pathways and obstruction site and degree of SVC were observed and analysed statistically . The drainage of SVCS was determined.

RESULTS

Anterior group of collateral pathways, vertebral venous plexus and posterior intercostal veins were related to obstruction of upper segment of SVC ( P < 0. 05) . Obstruction of the lower part of SVC has relation to the hemiazygos vein ( P < 0. 05) . The correlation between obstructive degree and distribution of collateral pathways was not distinct in this study ( P > 0. 05) . When obstruction of upper segment of SVC occurred, blood could return to heart through azygos vein or anterior group vessels. While lower segment of SVC was occluded, blood could reflux through azygos vein and hemiazygos vein to right atrium.

CONCLUSIONS

Distribution of collateral pathways in SVCS is closely related to the obstruction site of SVC, but not to the degree of obstruction.

[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.

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.

[The paraoxonase Gln-Arg192 polymorphism in patients with coronary heart disease in Chinese population]

OBJECTIVE

To investigate the 192 Gln-Arg polymorphism of paraoxonase (PON) gene and its relationship with serum lipids levels in patients with coronary heart disease in Chinese population.

METHODS

The genotype and allele frequency of paraoxonase gene 192 Gln-Arg polymorphism was assayed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Serum lipids were measured by enzymatic kits in 118 CHD patients and 128 healthy subjects whose fasting serum TG levels were < 1.82 mmol/L and TC levels < 6.2 mmol/L from a population of Chinese Han nationality in Chengdu area.

RESULTS

Both in CHD group and control group, the QR genotype of PON gene was the major one, and its frequencies were 0.578 and 0.525 respectively. No differences were found in PON gene Gln-Arg polymophism in the CHD group when compared with the control group. The frequency of R allele of PON gene in Chinese was significant higher than that in European and American Caucasians (0.51 vs. 0.26-0.31, P < 0.01) and Indian (0.51 vs. 0.17, P < 0.01), and significantly lower than that in Japanese (0.51 vs. 0.65, P < 0.01).

CONCLUSION

These results suggested that the Gln-Arg192 polymorphism of the PON1 gene was not associated with coronary heart disease in Chinese population.

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.

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.

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.

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).

[Study on apoE gene polymorphism in Chinese type II b hyperlipidemia]

OBJECTIVE

To study apolipoprotein(apo) E polymorphism and its relationship with plasma lipids and apolipoproteins levels in Chinese patients with type II b hyperlip oproteinemia.

METHODS

apoE genotypes were assayed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method, serum lipids were determined by enzyme method, and apolipoproteins were measured by radial immunodiffusion assay in 74 type II b hyperlipidemia patients whose fasting serum lipids levels were TG > or = 2.26 mmol/L, TC > or = 6.21 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 control group, the serum TG, TC, LDLC, nHDLC, apoA II, apoB100, apoC II, apoC III, apoE levels and TG/HDLC ratio in patients with type II b hyperlipidemia were significantly increased(P < 0.001), and the serum HDLC levels and apoE/apoC III ratio were significantly decreased (P < 0.05). ApoE3/3 genotype and allele epsilon 3 frequency in type II b hyperlipidemia group and control group were both the highest. In type II b hyperlipidemia group, allele epsilon 2 frequency tended to increase and allele epsilon 4 frequency tended to decrease as compared with those in the control group (P > 0.05). In type II b hyperlipidemia group the genotype of apoE2 was associated with higher serum TG, apoC II, apoE levels and apoE/apoC III ratio when compared with the genotype of apoE3; the genotype of apoE4 was associated with higher serum TC, nHDLC and apoE levels when compared with the genotypes E3 and E2 (P < 0.001).

CONCLUSION

The alleles epsilon 2 and epsilon 4 are associated with serum TG, TC, nHDLC, apoC II and apoE levels to some extent in type II b hyperlipide in Chinese population.