A Targeted Deep Sequencing Method to Quantify Endogenous Retrovirus Gag Sequence Variants and Open Reading Frames Expressed in Nonobese Diabetic Mice

Endogenous retroviruses (ERVs) are involved in autoimmune diseases such as type 1 diabetes (T1D). ERV gene products homologous to murine leukemia retroviruses are expressed in the pancreatic islets of NOD mice, a model of T1D. One ERV gene, Gag, with partial or complete open reading frames (ORFs), is detected in the islets, and it contains many sequence variants. An amplicon deep sequencing analysis was established by targeting a conserved region within the Gag gene to compare NOD with T1D-resistant mice or different ages of prediabetic NOD mice. We observed that the numbers of different Gag variants and ORFs are linked to T1D susceptibility. More importantly, these numbers change during the course of diabetes development and can be quantified to calculate the levels of disease progression. Sequence alignment analysis led to identification of additional markers, including nucleotide mismatching and amino acid consensus at specific positions that can distinguish the early and late stages, before diabetes onset. Therefore, the expression of sequence variants and ORFs of ERV genes, particularly Gag, can be quantified as biomarkers to estimate T1D susceptibility and disease progression.

[Association study between the KCNE family gene polymorphisms of potassium channel gene and the susceptibility of atrial fibrillation]

Objective: To investigate the relationship between KCNE family gene polymorphisms of potassium channel gene and the susceptibility of atrial fibrillation (AF). Methods: In the case-control study, a total of 648 subjects were studied, of which 338 patients with atrial fibrillation were selected from the Department of Cardiovascular Medicine, Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from January 2019 to December 2019, and 310 healthy people were selected from the physical examination population during the same period. DNA sequencing technology and polymerase chain reaction (PCR) were used to detect the genotype and allele frequency of rs1805127 of KCNE1, rs9984281 of KCNE2, rs9516, rs626930 of KCNE3 and rs12621643 of KCNE4. Results: The ages of subjects in atrial fibrillation group and control group were (69±13) and (73±8) years, respectively (P=0.077). Men subjects accounted for 57.70% (195 men) and 40.00% (124 men) in the two groups, respectively (P=0.092). The distribution frequencies of the allele C at rs1805127 of gene KCNE1, the allele A at rs9984281 of gene KCNE2 and the allele G at rs12621643 of gene KCNE4 were significantly different between groups (P<0.05). After adjustment for sex, smoking, hypertension, cardiac insufficiency and other factors, it was found that the increase in the frequency of the above three loci would increase the risk of atrial fibrillation (rs1805127 OR=7.064, 95%CI:1.559-31.997; rs9984281 OR=4.210, 95%CI:1.118-15.850; rs12621643 OR=2.679, 95%CI:1.025-6.998). Conclusion: The rs1805127 of KCNE1, the rs9984281 of KCNE2,the rs12621643 of KCNE4 were significantly associated with the susceptibility to atrial fibrillation.

[A multicenter randomized prospective study of concurrent chemoradiation with 60 Gy versus 50 Gy for inoperable esophageal squamous cell carcinoma]

Objective: To determine whether 60 Gy is superior to standard 50 Gy for definitive concurrent chemoradiation(CCRT) in esophageal squamous cell carcinoma (ESCC) using modern radiation technology in a phase Ⅲ prospective randomized trial. Methods: From April 2013 to May 2017, 331 patients from 22 hospitals who were pathologically confirmed with stage ⅢA-ⅣA ESCC were randomized to 60 Gy or 50 Gy with random number table. Total of 305 patients were analyzed, including 152 in 60 Gy group and 153 in 50 Gy group. The median age was 63 years, 242(79.3%) males and 63(20.7%) females. The median length of primary tumor was 5.6 cm. The clinical characteristics between two groups were comparable. All patients were delivered 2 Gy per fraction, 5 fractions per week. Concurrent weekly chemotherapy with docetaxel (25 mg/m(2)) and cisplatin (25 mg/m(2)) and 2 cycles consolidation chemotherapy with docetaxel (70 mg/m(2)) and cisplatin (25 mg/m(2), d1-3) were administrated. The primary endpoint was local/regional progression-free survival (LRPFS). The data were compared with Pearson chi-square test or Fisher's exact test. Results: At a median follow-up of 27.3 months, the disease progression rate was 37.5% (57/152), 43.8% (67/153) in the high and standard-dose group, respectively (χ(2)=1.251, P=0.263). The 1, 2, 3-year LRPFS rate was 75.4%, 56.8%, 52.1% and 74.2%, 58.4%, 50.1%, respectively (HR: 0.95, 95%CI: 0.69-1.31, P=0.761). The 1, 2, 3-year overall survival rate was 84.1%, 64.8%, 54.1% and 85.4%, 62.9%, 54.0%, respectively (HR: 0.98, 95%CI: 0.71-1.38, P=0.927). The 1, 2, 3-year progression-free survival rate was 70.8%, 54.2%, 48.5% and 65.5%, 51.9%, 45.1%, respectively (HR: 0.93, 95%CI: 0.68-1.26, P=0.621). The incidence rates in toxicities between the two groups were similar except for higher rate of severe pneumonitis in high dose group (χ(2)=11.596, P=0.021). Conclusions: The efficacy in disease control is similar between 60 Gy and 50 Gy using modern radiation technology concurrent with chemotherapy for ESCC. The 50 Gy should be recommended as the regular radiation dose with CCRT for ESCC.

Endogenous retrovirus Gag antigen and its gene variants are unique autoantigens expressed in the pancreatic islets of non-obese diabetic mice

Endogenous retrovirus (ERV) are remnants of ancient retroviruses that have been incorporated into the genome and evidence suggests that they may play a role in the etiology of T1D. We previously identified a murine leukemia retrovirus-like ERV whose Env and Gag antigens are involved in autoimmune responses in non-obese diabetic (NOD) mice. In this study, we show that the Gag antigen is present in the islet stromal cells. Although Gag gene transcripts were present, Gag protein was not detected in diabetes-resistant mice. Cloning and sequencing analysis of individual Gag genes revealed that NOD islets express Gag gene variants with complete open-reading frames (ORFs), in contrast to the diabetes-resistant mice, whose islet Gag gene transcripts are mostly non-ORFs. Importantly, the ORFs obtained from the NOD islets are extremely heterogenous, coding for various mutants that are absence in the genome. We further show that Gag antigens are stimulatory for autoreactive T cells and identified one islet-expressing Gag variant that contains an altered peptide ligand capable of inducing IFN-gamma release by the T cells. The data highlight a unique retrovirus-like factor in the islets of the NOD mouse strain, which may participate in key events triggering autoimmunity and T1D.

[Effects of interleukin-35 on the balance of helper T cell 17/regulatory T cell in peripheral blood of patients with oral lichen planus]

Objective: To investigate the effects of exogenous interleukin (IL)-35 on the balance of helper T cell 17 (Th17) and regulatory T cell (Treg) in peripheral blood of patients with oral lichen planus (OLP). Methods: Totally 12 peripheral blood samples of OLP patients (OLP group, one male and 11 female, 26-68 years old; four cases of reticular OLP and eight cases of erosive OLP) were collected from patients of Department of Oral Mucosal Specialist of the Affiliated Hospital of Guizhou Medical University from October to December 2016. During the same period, thirteen normal peripheral blood samples were collected from the Physical Examination Center of the Affiliated Hospital of Guizhou Medical University (normal control group, one male and 12 female, 20-68 years old). The peripheral blood mononuclear cells (PBMC) were extracted in sterile condition and CD4+ T cells were sorted by flow cytometry (FCM). Quantitative real-time PCR (qPCR) technique was used to detect the mRNA expression levels of retinoid-related orphan nuclear γt (RORγt) and forkhead box3 (Foxp3). The CD4+ T cells were divided into experimental group and control group. The CD4+ T cells of experimental group were cultured in vitro by adding rhIL-35, and the CD4+ T cells of control group were cultured with the same volume of phosphate buffered saline (PBS). After the completion of the culture, the cells were collected. The expression levels of the same factors were detected by qPCR. Results: The expression [M(Q(25), Q(75))] of Foxp3 [0.15 (0.09, 0.30)] and RORγt mRNA [1.04 (0.45, 2.15)] in the CD4+ T cells of OLP were significantly higher than those in normal control group [0.04 (0.02, 0.06), 0.10 (0.05, 0.11)] (Z=-4.134, P<0.01; Z=-3.699, P<0.01). The ratio of ROR γt/Foxp3 mRNA in OLP group [6.22(3.67, 15.34)] was higher than that in normal control group [2.50 (1.24, 5.23)] (Z=-2.665, P=0.007). In the CD4+ T cells of OLP patients, the expression of Foxp3 mRNA in the experiment group [0.40 (0.21, 1.22)] was higher than that in the control group [0.15 (0.11, 0.26)](Z=-2.510, P=0.012), and the expression of ROR γt mRNA between two groups showed no significant difference (P>0.05). The ROR γt/Foxp3 mRNA ratio [3.44 (1.55, 8.16)] of the experiment group was lower than that in the control group [6.22 (4.43, 12.21)] (Z=-2.746, P=0.006). Conclusions: There was a Th17/Treg imbalance with predominated by Th17 cells in the peripheral blood of patients with OLP. Exogenous rhIL-35 had an immunomodulatory effect on the balance of Th17/Treg.

Peptides of endogenous retrovirus Gag gene variants are not agonistic ligands for autoreactive T cells in non-obese diabetic mice

Endogenous retroviruses (ERV) have been isolated from the pancreatic islets of non-obese diabetic (NOD) mice. We previously demonstrated that a murine leukemia retrovirus–like ERV Gag protein was secreted together with exosomes by an insulinoma and by primary islet mesenchymal stem cells. Here, we further demonstrated that Gag is an effective antigen to stimulate IFN-gamma production by autoreactive T cells using recombinant Gag protein or virus-like particles (VLPs) expressing the Gag gene. However, candidate peptides of this Gag protein were not effective in stimulating the T cells. Upon analyses of ERV Gag genes expressed in the islets of prediabetic NOD mice, we were surprised to find multiple Gag gene variants with complete open-reading frames. These results suggested the expression of different endogenous proviruses, or alternatively, the detection of point mutations incurred during viral replication. A new batch of altered peptides was synthesized reflecting the variations among the Gag gene variants, and a few of them induced detectable amount of cytokine secretion from the T cells. But, the levels of IFN-gamma induced by the peptides were much lower than that induced by the Gag protein and the VLPs, suggesting a low affinity activation. This weak T-cell-stimulating activity of the Gag peptides was further confirmed by testing diabetogenic T-cell clones, as well as by using MHC tetramers loaded with candidate peptides. The data suggest that ERV Gag or its gene variants may trigger autoimmunity via a pathway that could be independent from direct presentation of viral peptides to autoreactive T cells.

Shock wave propagation, plasticity, and void collapse in open-cell nanoporous Ta

We systematically investigate the wave propagation, plasticity and void collapse, as well as the effects of porosity, specific surface area and impact velocity, in a set of open-cell nanoporous Ta, during shock compression, via performing large-scale non-equilibrium molecular dynamics simulations. The shock wave propagation presents an impedance, sensitive to porosity, but not to specific surface area. Such surprising phenomena are due to the similar sensitivities in density and stress variations to porosity or specific surface area. Upon impact, shock front shapes change from ramped to steep ones, with increasing porosity, specific surface area or impact velocity, owing to the transition from the heterogeneous to homogeneous plasticity along transverse directions. This transition of plasticity arises by (i) the strong impedance on large deformation bands as porosity increases; and (ii) the transition from deformation twinning to dislocation slips, and to amorphization, as the specific surface area or impact velocity increases. Shock-induced plasticity, including their nucleation, growth and interactions, also facilitates the collapse of voids.

miR-30 disrupts senescence and promotes cancer by targeting both p16INK4A and DNA damage pathways

miR-30 is a microRNA frequently overexpressed in human cancers. However, the biological consequence of miR-30 overexpression in cancer has been unclear. In a genetic screen, miR-30 was found to abrogate oncogenic-induced senescence, a key tumor-suppressing mechanism that involves DNA damage responses, activation of p53 and induction of p16^INK4A. In cells and mouse models, miR-30 disrupts senescence and promotes cancer by suppressing 2 targets, CHD7 and TNRC6A. We show that while CHD7 is a transcriptional coactivator essential for induction of p16^INK4A in senescent cells, TNRC6A, a miRNA machinery component, is required for expression and functionality of DNA damage response RNAs (DDRNAs) that mediate DNA damage responses and p53 activation by orchestrating histone modifications, chromatin remodeling and recruitment of DNA damage factors at damaged sites. Thus, miR-30 inhibits both p16^INK4A and p53, 2 key senescence effectors, leading to efficient senescence disruption. These findings have identified novel signaling pathways mediating oncogene-induced senescence and tumor-suppression, and revealed the molecular and cellular mechanisms underlying the oncogenic activity of miR-30. Thus, the miR-30/CHD7/TNRC6A pathway is potentially a novel diagnostic biomarker and therapeutic target for cancer.

Surface premelting/recrystallization governing the collapse of open-cell nanoporous Cu via thermal annealing

We systematically investigate the collapse of a set of open-cell nanoporous Cu (np-Cu) materials with the same porosity and shape but different specific surface areas, during thermal annealing, by performing large-scale molecular dynamics simulations. Two mechanisms govern the collapse of np-Cu. One is direct surface premelting, facilitating the collapse of np-Cu, when the specific surface area is less than a critical value (∼2.38 nm-1). The other is recrystallization followed by surface premelting, accelerating the sloughing of ligaments and the annihilation of voids, when the critical specific surface area is exceeded. Surface premelting results from surface reconstruction by prompting localized "disordering" and "chaos" on the surface, and the melting temperature reduces linearly with the increase of the specific surface area. Recrystallization is followed by surface premelting as the melting temperature is below the supercooling point, where a liquid is unstable and instantaneously recrystallizes.

Type 1 diabetes pathogenesis is modulated by spontaneous autoimmune responses to endogenous retrovirus antigens in NOD mice

Secreted microvesicles (MVs) are potent inflammatory triggers that stimulate autoreactive B and T cells, causing Type 1 Diabetes in non-obese diabetic (NOD) mice. Proteomic analysis of purified MVs released from islet cells detected the presence of endogenous retrovirus (ERV) antigens, including Env and Gag sequences similar to the well-characterized murine leukemia retroviruses. This raises the possibility that ERV antigens may be expressed in the pancreatic islets via MV secretion. Using virus-like particles produced by co-expressing ERV Env and Gag antigens, and a recombinant gp70 Env protein, we demonstrated that NOD but not diabetes-resistant mice developed anti-Env autoantibodies that increase in titer as disease progresses. A lentiviral-based RNA interference knockdown of Gag revealed that Gag contributes to the MV-induced T-cell response, whose diabetogenic function can be demonstrated via cell-transfer into immune-deficient mice. Finally, we observed that Gag and Env are expressed in NOD islet-derived primary mesenchymal stem cells (MSCs). However, MSCs derived from the islets of diabetes-resistant mice do not express the antigens. Taken together, abnormal ERV activation and secretion of MVs may induce anti-retroviral responses to trigger autoimmunity.

[Clinicopathologic features of hepatocellular carcinoma patients surviving more than 10 years after radical hepatectomy]

Objective: To clarify the clinicopathologic features of hepatocellular carcinoma (HCC) patients survived more than 10 years after radical hepatectomy. Methods: Two hundreds and fifty-two patients who underwent curative resection for HCC between January 1999 and March 2006 at Department of Hepatopancreatobiliary Surgery, Affiliated Hospital of Qingdao University were included.There were 217 male cases and 35 female cases aging from 17 to 82 years with median age of (53.8±10.5)years. Followed by March 31 2016, clinicopathologic factors in 10-year survivors and patients who died within 10 years were compared by χ(2) test, Kaplan-Meier survival analysis and Cox proportional hazards model and the prognostic factors affecting survival were identified. Results: All patients were followed-up for 4.0 to 205.7 months with median time of 53.4 months. The 10-year overall survival rate was 26%, there were 62 cases(26.2%) who survived for more than 10 years after initial hepatectomy. In survival >10-year group, the paitents with ALT<40 U/L, gamma-glutamyl transpeptidase<64 U/L, albumin≥35 g/L, without liver cirrhosis and portal hypertension, Child-Pugh grade A, no blood transfusion, AFP≤20 μg/L, tumor size ≤5.0 cm, single tumor, high differentiation, TNM stage Ⅰ and TACE negative after resection were more than the patients in survival <10-year group (P<0.05). In multivariate analysis, Child-Pugh grade A, the tumor size ≤5.0 cm and TACE negative after resection were favorable independent factors associated with 10-year survival (P<0.05). Conclusion: Based on the results of the study, Child-Pugh grade A, tumor size ≤5.0 cm and TACE negative after resection at initial hepatectomy might be biologically favorable conditions for patients surviving more than 10 years.

Media influence on drive for thinness, body satisfaction, and eating attitudes among young women in Hong Kong and China

The present study examined the impact of thin-ideal media exposure on Chinese women's drive for thinness, attitudes towards body shape, and eating attitude. Women were assigned to one of two video conditions, which portrayed the thin-ideal (experimental) or was neutral (control group), in terms of content. A total of 83 young women from Hong Kong (N = 38) and Shanghai (N = 45), aged between 18 and 25 years (M_age = 22.7) participated in the study. A significant interaction was observed between the experimental video condition and location. Hong Kong women in the experimental group experienced greater levels of body dissatisfaction than Shanghai women exposed to the same condition. Exposure to thin-ideal media produced an increase in drive for thinness, body dissatisfaction and problematic eating attitudes regardless of location, with a greater immediate impact shown in Hong Kong women.

The epithelial-mesenchymal transition mediator S100A4 maintains cancer-initiating cells in head and neck cancers

Cancer-initiating cells (CIC) comprise a rare subpopulation of cells in tumors that are proposed to be responsible for tumor growth. Starting from CICs identified in head and neck squamous cell carcinomas (HNSCC), termed head and neck cancer-initiating cells (HN-CIC), we determined as a candidate stemness-maintaining molecule for HN-CICs the proinflammatory mediator S100A4, which is also known to be an inducer of epithelial-mesenchymal transition. S100A4 knockdown in HN-CICs reduced their self-renewal capability and their stemness and tumorigenic properties, both in vitro and in vivo. Conversely, S100A4 overexpression in HNSCC cells enhanced their stem cell properties. Mechanistic investigations indicated that attenuation of endogenous S100A4 levels in HNSCC cells caused downregulation of Notch2 and PI3K (phosphoinositide 3-kinase)/pAKT along with upregulation of PTEN, consistent with biological findings. Immunohistochemical analysis of HNSCC clinical specimens showed that S100A4 expression was positively correlated with clinical grading, stemness markers, and poorer patient survival. Together, our findings reveal a crucial role for S100A4 signaling pathways in maintaining the stemness properties and tumorigenicity of HN-CICs. Furthermore, our findings suggest that targeting S100A4 signaling may offer a new targeted strategy for HNSCC treatment by eliminating HN-CICs.

The miR-17-92 cluster of microRNAs confers tumorigenicity by inhibiting oncogene-induced senescence

In mammalian cells, activation of oncogenes usually triggers innate tumor-suppressing defense mechanisms, including apoptosis and senescence, which are compromised by additional mutations before cancers are developed. The miR-17-92 gene cluster, a polycistron encoding six microRNAs (miRNA), is frequently overexpressed in human cancers and has been shown to promote several aspects of oncogenic transformation, including evasion of apoptosis. In the current study, we show a new role of miR-17-92 in inhibiting oncogenic ras-induced senescence. Further dissection of the miRNA components in this cluster reveals that the miR-17/20a seed family accounts for this antisenescence activity. miR-17 and miR-20a are both necessary and sufficient for conferring resistance to ras-induced senescence by directly targeting p21(WAF1), a key effector of senescence. By contrast, these components are not essential for the ability of miR-17-92 to evade Myc-induced apoptosis. Moreover, disruption of senescence by miR-17-92 or its miR-17/20a components leads to enhanced oncogenic transformation by activated ras in primary human cells. Taken together with previous reports that miR-17-92 inhibits apoptosis by suppressing Pten via the miR-19 components, our results indicate that this miRNA cluster promotes tumorigenesis by antagonizing both tumor-suppressing mechanisms, apoptosis, and senescence, through the activities of different miRNA components encoded in this cluster.

Tid1 functions as a tumour suppressor in head and neck squamous cell carcinoma

Human tumourous imaginal disc (Tid1), a human homologue of the Drosophila tumour suppressor protein Tid56, is involved in multiple intracellular signalling pathways such as apoptosis, cell proliferation, and cell survival. Here, we investigated the anti-tumourigenic activity of Tid1 in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo. Firstly, the clinical association between Tid1 expression and progression of HNSCC was explored. It was found that expression of Tid1 was negatively associated with tumour status, recurrence, and survival prognosis using immunohistochemical analysis of primary HNSCC patient tumour tissue. Secondly, ectopic expression of Tid1 in HNSCC cells was shown to significantly inhibit cell proliferation, migration, invasion, anchorage-independent growth, and xenotransplantation tumourigenicity. Thirdly, we showed that overexpression of Tid1 attenuated EGFR activity and blocked the activation of AKT in HNSCC cells, which are known to be involved in the regulation of survival in HNSCC cells. On the other hand, ectopic expression of constitutively active AKT greatly reduced apoptosis induced by Tid1 overexpression. Together, these findings suggest that Tid1 functions as a tumour suppressor in HNSCC tumourigenesis.

Good death study of elderly patients with terminal cancer in Taiwan

OBJECTIVES

Over half of all terminal cancer patients in Taiwan are 65 or older, thus demonstrating the importance of terminal care for elderly people. This study investigates the good death status of elderly patients with terminal cancer, comparing the differences in the degree of good death among elderly and younger groups, and exploring the factors related to the good death score.

METHODS

Three hundred and sixty-six patients with terminal cancer admitted to a palliative care unit were enrolled. Two structured measurements, the good death scale and the audit scale for good death services, were used as the instruments in the study.

RESULTS

The scores of individual items and of the good death scale were increased significantly in both elderly (n = 206, 56.3%) and younger (n = 160, 43.7%) groups from the time of admission to just prior to death. However, the elderly group had significantly lower scores in 'awareness' (t = -3.76, P < 0.001), 'propriety' (t = -2.92, P < 0.01) and 'timeliness' (t = -2.91, P < 0.01) than the younger group prior to death. Furthermore, because of a lack of truth-telling, the elderly group also had significantly lower scores than the younger group in both 'respect for autonomy' and 'decision-making participation' (t = -2.17, P < 0.05; t = -2.21, P < 0.05, respectively). Multiple regression analysis revealed that 'respect for autonomy' (OR = 1.22, 95% CI = 0.76-1.67) and 'verbal support '(OR = 0.93, 95% CI = 0.34-1.51) were two independent correlates of the good death score in the elderly group.

CONCLUSION

The dilemma of truth-telling compromises the autonomy of the elderly patients with terminal cancer and consequently affects their good death scores. The palliative care team should emphasize the issue of truth-telling in the process of caring for terminally ill cancer patients, especially elderly patients.

Hydroxyapatite/titania sol-gel coatings on titanium-zirconium alloy for biomedical applications

A simple sol-gel method was developed for hydroxyapatite/titania (HA/TiO(2)) coatings on non-toxic titanium-zirconium (TiZr) alloy for biomedical applications. The HA/TiO(2)-coated TiZr alloy displayed excellent bioactivity when soaked in a simulated body fluid (SBF) for an appropriate period. Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectrometry were used to characterize the phase transformations and the surface structures and to assess the in vitro tests. The HA/TiO(2) layers were spin-coated on the surface of TiZr alloy at a speed of 3000rpm for 15s, followed by a heat treatment at 600 degrees C for 20min in an argon atmosphere sequentially. The TiO(2) layer exhibited a cracked surface and an anatase structure and the HA layer displayed a uniform dense structure. Both the TiO(2) and HA layers were 25microm thick, and the total thickness of the HA/TiO(2) coatings was 50microm. The TiZr alloy after the above HA/TiO(2) coatings displayed excellent bone-like apatite-forming ability when soaked in SBF and can be anticipated to be a promising load-bearing implant material.

RNA interference against retroviruses

Bang and Ellerman, and later Peyton Rous, reported the first identification of transmissible cancer-causing agents, which later turned out to be avian retroviruses. Today avian retroviruses are important models for study of retrovirus replication and pathogenesis, and also important pathogens of domestic fowl. Here we describe the use of RNA interference (RNAi) in live chick embryos to block replication of an avian retrovirus. We also describe inhibition of ASLV and HIV replication in cell culture with RNAi.

Inhibition of retroviral pathogenesis by RNA interference

BACKGROUND

RNA interference (RNAi) is a newly discovered cellular defense system that is known to suppress replication of genomic parasites in model organisms. It has been widely conjectured that RNAi may also serve as an antiviral system in vertebrates.

RESULTS

Retroviral infection could be initiated by electroporation of cloned Rous sarcoma virus (RSV) proviral DNA into the developing chick neural tube. Coelectroporation of proviral DNA and short double-stranded RNAs matching sequences of avain retroviruses, which were designed to induce RNAi against RSV, inhibited viral replication. Replication of RSV after electroporation resulted in disruption of embryonic development and early death, but this, too, could be suppressed by RNAi against the RSV genome. RNAi could also inhibit the growth of RSV and HIV in cell culture. Analysis of the step of the retroviral life cycle that is inhibited by RNAi revealed that it primarily prevented accumulation of the viral RNAs synthesized late during infection. RNA genomes introduced in viral particles early during infection were less sensitive.

CONCLUSIONS

RNAi can block retroviral infection in vertebrates. The tissue electroporation method described here should allow RNAi to be used widely to study gene function and control of infection in vertebrate animals.

Determination of 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP) and its metabolite 2-hydroxyamino-PhIP by liquid chromatography/electrospray ionization-ion trap mass spectrometry

2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is the most abundant heterocyclic aromatic amine found in cooked meat. It is metabolically activated by the human cytochrome P450 enzymes to form the carcinogenic metabolite N2-OH-PhIP. PhIP has been found to induce tumors in rats and is a suspected human carcinogen. In the present work, we have developed and validated a liquid chromatography-electrospray ionization/ion trap mass spectrometry (LC-ESI/ITMS) method for the determination of PhIP and N2-OH-PhIP. PhIP was incubated with microsomes prepared from the human liver; the PhIP and N2-OH-PhIP formed were isolated from the biomatrices by solid-phase extraction using C18 cartridges, with recoveries greater than 86%. Subsequently, the products were separated on a microbore reversed-phase C18 liquid chromatograph coupled to an ESI-ITMS. The ESI interface and the ITMS were tuned for various parameters, and data acquisition was performed in selective ion monitoring mode. The detection limit of PhIP and N2-OH-PhIP was 1 and 10 pg, respectively. The method is highly sensitive and selective, has simple sample preparation protocols, and should be applicable to the study of the metabolic activation of PhIP in various human tissues.

Hammerhead ribozyme targeting human platelet-derived growth factor A-chain mRNA inhibited the proliferation of human vascular smooth muscle cells

Platelet-derived growth factor (PDGF) A-chain contributes to the pathogenesis of cardiovascular proliferative diseases, such as hypertensive vascular disease, atherosclerosis, and re-stenosis of an artery after angioplasty. To develop a ribozyme against human PDGF A-chain mRNA as a gene therapy for human arterial proliferative diseases, we designed and synthesized a 38-base hammerhead ribozyme to cleave human PDGF A-chain mRNA at the GUC sequence at nucleotide 591. In the presence of MgCl(2), synthetic hammerhead ribozyme to human PDGF A-chain mRNA cleaved the synthetic target RNA to two RNA fragments at a predicted size. Doses of 0.01-1.0 microM hammerhead ribozyme to human PDGF A-chain mRNA significantly inhibited angiotensin II (Ang II) and transforming growth factor (TGF)-beta(1)-induced DNA synthesis in vascular smooth muscle cells (VSMC) from human in a dose-dependent manner. One micromolor of hammerhead ribozyme to human PDGF A-chain mRNA significantly inhibited Ang II-induced PDGF A-chain mRNA and PDGF-AA protein expressions in VSMC from humans. These results indicate that the designed hammerhead ribozyme to human PDGF A-chain mRNA effectively inhibited growth of human VSMC by cleaving the PDGF A-chain mRNA and inhibiting the PDGF-AA protein expression in human VSMC. This suggests that the designed hammerhead ribozyme to PDGF A-chain mRNA is a feasible gene therapy for treating arterial proliferative diseases.

Endogenous angiotensin II suppresses insulin signaling in vascular smooth muscle cells from spontaneously hypertensive rats

BACKGROUND

Angiotensin II (Ang II) has been reported to inhibit insulin signaling at multiple levels in vascular smooth muscle cells (VSMC) in vitro. We have demonstrated that VSMC from spontaneously hypertensive rats (SHR) produce Ang II in a homogeneous culture.

OBJECTIVE

In the current study, we investigated influences of endogenous Ang II on insulin signaling in VSMC from SHR.

DESIGN AND METHODS

Phosphatidylinositol 3-kinase (PI3-kinase) activity, insulin receptor substrate-1 (IRS-1) associated tyrosine phosphorylation, and p85 subunit of PI3-kinase were measured in VSMC from SHR and normotensive Wistar-Kyoto (WKY) rats in the absence and presence of Ang II type 1 receptor antagonist RNH6270 and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) inhibitor U0126.

RESULTS

Insulin treatment increased PI3-kinase activity in VSMC from WKY rats in a dose-dependent manner. In contrast, insulin treatment of VSMC from SHR did not affect PI3-kinase activity. However, co-treatment of VSMC from SHR with RNH6270 and insulin, increased PI3-kinase activity. PI3-kinase activity, IRS-1-associated tyrosine phosphorylation and p85 subunit of PI3-kinase in VSMC from WKY rats decreased in response to treatment with Ang II and returned to control levels upon co-treatment with U0126. Basal levels of PI3-kinase activity, IRS-1-associated tyrosine phosphorylation, and p85 subunit of PI3-kinase were significantly lower in VSMC from SHR than in cells from WKY rats. U0126 treatment of VSMC from SHR significantly increased levels of PI3-kinase activity, IRS-1-associated tyrosine phosphorylation, and p85 subunit of PI3-kinase.

CONCLUSION

These results indicate that endogenous Ang II suppresses insulin signaling in VSMC from SHR by activating extracellular signal-regulated kinase. These findings suggest that tissue Ang II may play a role in insulin resistance in hypertension.

Use of the Alberta Stroke Program Early CT Score (ASPECTS) for assessing CT scans in patients with acute stroke

BACKGROUND AND PURPOSE

Clinicians are insecure reading CT scans by using the one-third rule for acute middle cerebral artery stroke (1/3 MCA rule) before treating patients with recombinant tissue plasminogen activator. The 1/3 MCA rule is a poorly defined volumetric estimate of the size of cerebral infarction of the MCA. A 10-point quantitative topographic CT scan score, the Alberta Stroke Program Early CT Score (ASPECTS), is described and illustrated. A sharp increase in dependence and death occurs with an ASPECTS of 7 or less. We describe how to use ASPECTS and why it works with CT scans obtained on all commonly used axial baselines. We also describe interobserver reliability among clinicians from different specialties and with different experience in reading CT scans in the context of acute stroke.

METHODS

The six physicians who developed ASPECTS answered a questionnaire on precisely how they interpret and use ASPECTS. The ASPECTS areas as interpreted by these physicians were compared with one another and with standards in the literature. kappa statistics were used to assess the interobserver reliability of ASPECTS versus the 1/3 MCA rule.

RESULTS

The exact methods of interpretation varied among the six individual observers, with either a 3:3 or 4:2 split on the specific questions. The overall interobserver agreement was good compared with that of the 1/3 MCA rule. Normal anatomic vascular and interobserver variations explain why ASPECTS can be applied with different CT axial baselines.

CONCLUSION

ASPECTS is a systematic, robust, and practical method that can be applied to different axial baselines. Clinician agreement is superior to that of the 1/3 MCA rule.

Effects of the L- and N-type calcium channel blocker cilnidipine on growth of vascular smooth muscle cells from spontaneously hypertensive rats

Cultured vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) show exaggerated growth compared with cells from Wistar-Kyoto (WKY) rats. Calcium antagonists have recently been reported to have an in vivo antiproliferative effect on hypertensive cardiovascular organs. We investigated the effects of the calcium antagonist cilnidipine that blocks both L- and N-type calcium channels on the growth of VSMC from SHR. Cilnidipine (1 and 10 microM) significantly inhibited basal DNA synthesis in VSMC from both rat strains; the inhibition was significantly larger in VSMC from SHR than in cells from WKY rats, and was significantly greater than effects of nifedipine. Cilnidipine (1 microM) significantly inhibited serum-stimulated DNA synthesis in VSMC from both rat strains. The inhibition was more marked in VSMC from SHR than in cells from WKY rats. Angiotensin II, platelet-derived growth factor (PDGF)-AA, and phorbol-12-myristate-13-acetate dose-dependently increased DNA synthesis in VSMC from SHR but not in cells from WKY rats. Cilnidipine (1 microM) significantly suppressed this increase in DNA synthesis in VSMC from SHR. Expression of basic fibroblast growth factor (bFGF), transforming growth factor-beta1, and PDGF A-chain mRNAs was markedly greater in VSMC from SHR than in cells from WKY rats. Cilnidipine (1 microM) significantly inhibited the expression of TGF-beta1 mRNA in VSMC from SHR but not in cells from WKY rats. These findings suggest that cilnidipine exerts its antiproliferative effects through the inhibition of DNA synthesis induced by growth-promoting factors and by inhibiting the expression of TGF-beta1 mRNA in VSMC from SHR.

Sedation for refractory symptoms of terminal cancer patients in Taiwan

This study assessed sedation in terminal cancer patients in terms of three characteristics: frequency; relationship to intractable symptoms; and the extent to which medical staff, family, and patients found sedation to be ethically acceptable and efficacious. Two hundred seventy-six consecutive patients, who were admitted to the palliative care unit of National Taiwan University Hospital in Taiwan between August 1998 and the end of May 1999, were enrolled. A recording form was completed every day. This included demographic data, pain and common symptom scores, and the use of sedation in the terminal phase. Seventy (27.9%) of 251 patients who died received sedation. Sedation was administered to relieve agitated delirium in 40 (57.1%), dyspnea in 16 (22.8%), severe pain in 7 (10%) and insomnia in 5 (7.2%). The drugs used for sedation were haloperidol in 35 (50%), midazolam in 17 (24.3%), and rapidly increasing dosage of morphine in 9 (12.9%). In fewer than half (42.9%) of the patients, sedation was with the consent of both patient and family, and half (50%) had the consent of family alone. The overwhelming majority of medical staff and family felt the decision to use terminal sedation was ethically acceptable. There was no significant difference in survival time between sedated and non-sedated patients (28.49 vs. 24.71 days, t = -0.791, P = 0.430). Positive ethical acceptability and higher satisfaction with symptom control with terminal sedation were found in both medical staff and family in this study. Further work is needed to find the most appropriate time of intervention and to improve management of refractory symptoms in dying patients.

Anatomy of a preferred target site for the bacterial insertion sequence IS903

Like many transposons the bacterial insertion sequence IS903 was thought to insert randomly. However, using both genetic and statistical approaches, we have derived a target site for IS903 that is used 84% of the time. Computational and genetic analyses of multiple IS903 insertion sites predicted a preferred target consisting of a 21 bp palindromic pattern centered on the 9 bp target duplication generated during transposition. Here we show that targeting can be dissected into four components: the 5 bp flanking sequences, the most important sequences required for site-specific insertion; the 7 bp palindromic core within the target duplication; the dinucleotide pair at the transposon-target junction; and the local DNA context. Finally, using a substrate with multiple target sites we show that a target site is more likely found by a local bind-and-slide model and not by extended DNA tracking.

Inhibition of vascular smooth muscle cell proliferation by DNA-RNA chimeric hammerhead ribozyme targeting to rat platelet-derived growth factor A-chain mRNA

BACKGROUND

Spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells (VSMC) show exaggerated growth and increasingly express platelet-derived growth factor (PDGF) A-chain mRNA compared to VSMC from normotensive Wistar-Kyoto (WKY) rats.

OBJECTIVE

To investigate the effects of designed DNA-RNA chimeric hammerhead ribozyme to rat PDGF A-chain on exaggerated growth of VSMC from SHR.

DESIGN AND METHODS

We designed and synthesized a 38-base DNA-RNA chimeric hammerhead ribozyme with two phosphorothioate linkages at the 3' terminal to cleave rat PDGF A-chain mRNA at the GUC sequence at nucleotide 921. We confirmed the cleavage activity of designed ribozyme by in vitro cleavage reaction and by lipofectin-mediated transfection of ribozyme into VSMC.

RESULTS

Doses of 0.1 and 1 micromol/l DNA-RNA chimeric ribozyme dose-dependently inhibited basal DNA synthesis in VSMC from SHR. A dose of 1 micromol/l DNA-RNA chimeric ribozyme time-dependently inhibited basal DNA synthesis in VSMC from SHR. However, the same doses of all-RNA ribozyme had no effects on DNA synthesis in VSMC from SHR. Fluorescein isothiocyanate-labeled DNA-RNA chimeric ribozyme was recognized in cytosol at 30 min, and in nucleus at 60 min after lipofectin transfection. A dose of 1 micromol/l DNA-RNA chimeric ribozyme significantly inhibited expressions of both PDGF A-chain mRNA and PDGF-AA protein in VSMC from SHR, but not from WKY rats.

CONCLUSION

These results indicated that the designed DNA-RNA chimeric ribozyme to PDGF A-chain mRNA effectively and specifically inhibited the exaggerated growth of VSMC from SHR at low concentrations, which were mediated by the reduction of PDGF A-chain mRNA and PDGF-AA protein expressions.

Role of endogenous angiotensin II in the increased expression of growth factors in vascular smooth muscle cells from spontaneously hypertensive rats

In culture, vascular smooth muscle cells (VSMC) derived from spontaneously hypertensive rats (SHR) show exaggerated growth compared with cells from normotensive Wistar-Kyoto (WKY) rats. SHR-derived VSMC express higher levels of transforming growth factor (TGF)-beta1, platelet-derived growth factor (PDGF) A-chain, and basic fibroblast growth factor (bFGF) mRNAs than cells from WKY rats. We have recently observed production of angiotensin II (Ang II) in homogeneous cultures of VSMC from SHR. In the current study we investigated the contribution of endogenous Ang II to increased expression of the above-mentioned growth factors in VSMC from SHR. The levels of mRNAs encoding TGF-beta1, PDGF A-chain, and bFGF were determined by reverse transcription-polymerase chain reaction and were much higher in VSMC from SHR than in cells from WKY rats. The basal level of Ang II-like immunoreactivity (LI) in conditioned medium as determined by radioimmunoassay was significantly higher in VSMC from SHR than in cells from WKY rats. Isoproterenol is known to induce angiotensinogen gene significantly increased Ang II-LI in VSMC from both WKY rats and SHR. Isoproterenol also increased angiotensinogen, TGF-beta1, PDGF A-chain, and bFGF mRNAs in VSMC from SHR. An angiotensin-converting enzyme inhibitor delapril significantly decreased Ang II-LI in VSMC from WKY rats and SHR. Delapril considerably decreased the levels of TGF-beta1, PDGF A-chain, and bFGF mRNAs in VSMC from SHR. An Ang II type 1 receptor antagonist CV 11974 decreased the levels of TGF-beta1, PDGF A-chain, and bFGF mRNAs, and the levels of TGF-beta1, PDGF-AA, and bFGF proteins in VSMC from SHR. These findings suggest that increased generation of Ang II is associated with enhanced expression of TGF-beta1, PDGF A-chain, and bFGF, and the increases in the levels of these growth factors by endogenous Ang II may contribute to the exaggerated growth of VSMC from SHR.

Ribozyme to human TGF-beta1 mRNA inhibits the proliferation of human vascular smooth muscle cells

Transforming growth factor-beta (TGF-beta) has been reported to be involved in the pathogenesis of cardiovascular proliferative diseases such as hypertensive vascular disease, atherosclerosis, and arterial restenosis after angioplasty. We designed a 38-base DNA-RNA chimeric hammerhead ribozyme to cleave human TGF-beta1 mRNA as a gene therapy for human arterial proliferative diseases. In the presence of MgCl(2), synthetic ribozyme to human TGF-beta1 mRNA cleaved the synthetic target RNA into two RNA fragments of predicted size. A control mismatch ribozyme, with one different base in the catalytic loop region, was inactive. DNA-RNA chimeric ribozyme (0. 01-1.0 microM) significantly inhibited angiotensin II (Ang II)-stimulated DNA synthesis in a dose-dependent manner in human vascular smooth muscle cells (VSMC). The mismatch ribozyme did not affect Ang II-stimulated DNA synthesis in the cells. DNA-RNA chimeric ribozyme (1.0 microM) inhibited the proliferation of human VSMC in the presence of Ang II. DNA-RNA chimeric ribozyme (1.0 microM) significantly inhibited Ang II-stimulated TGF-beta1 mRNA and protein expression in human VSMC. These results indicate that the designed DNA-RNA chimeric hammerhead ribozyme targeted to human TGF-beta1 mRNA can effectively and potentially inhibit growth of human VSMC by cleaving the TGF-beta1 mRNA. This finding suggests that this ribozyme will be useful in the gene therapy of arterial proliferative diseases.

Ethical dilemmas in palliative care: a study in Taiwan

OBJECTIVES

To investigate the incidence and solution of ethical dilemmas in a palliative care unit.

DESIGN

Health care workers recorded daily all dilemmas in caring for each patient.

SETTING

Palliative care unit of National Taiwan University Hospital in Taiwan.

PATIENTS

Two hundred and forty-six consecutive patients with terminal cancer during 1997-8.

MAIN MEASUREMENT

Ethical dilemmas in the questionnaire were categorised as follows: telling the truth; place of care; therapeutic strategy; hydration and nutrition; blood transfusion; alternative treatment; terminal sedation; use of medication, and others.

RESULTS

The type and frequency of ethical dilemmas encountered were: place of care (33.3%); truth-telling (32.1%); hydration and nutrition (25.2%); therapeutic strategy (24.8%), and use of medication (19.1%). Ethical problems relating to the place of care and to therapeutic strategy were unlikely to be solved with increased hospital stay and some ethical dilemmas remained unsolved even in the final week in hospital, including place of care (23.2%), truth-telling (17.1%) and therapeutic strategy (11.4%). Problems of truth-telling occurred in nearly half (42.6%) of patients over sixty-five-years-old. Conflicts about blood transfusion were experienced in all patients below 18-years-old, and the dilemmas concerning the place of care occurred most frequently with head and neck cancer patients (43.8%).

CONCLUSIONS

The solution of ethical dilemmas required refocusing by medical professionals on the importance of continuing communication. Improved ethical training for professionals would contribute to solving the moral dilemmas of palliative care.

Instrumental and bioanalytical measures of persistent organochlorines in blue mussel (Mytilus edulis) from Korean coastal waters

Blue mussels (Mytilus edulis) collected from 34 locations along the south and east coast of Korea were analyzed for polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides. Maximum concentrations of PCBs and total OC pesticides were 98.5 and 20.5 ng/g, wet weight, respectively. Extracts were fractionated by Florisil chromatography and each fraction was screened for dioxin-like activity in vitro, using recombinant rat hepatoma cells (H4IIE-luc). Fraction 2 (F-2), which contained hexachlorocyclohexanes, chlordanes, p,p'-DDD, and p,p'-DDT, generally elicited significant dioxin-like activity compared to control, whereas Fraction 1 (F-1), which contained PCBs, p,p'-DDE, and hexachlorobenzene, did not. The greatest magnitude of dioxin-like response observed was 44% of the maximum response elicited by a 2,000 pM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) standard. The relatively low magnitudes of dioxin-like response observed for F-1 samples were consistent with the relatively low PCB concentrations. At concentrations equal to the maximum observed in the mussel samples, neither individual OC pesticides nor a mixture of OC pesticides yielded a significant dioxin-like response in the H4IIE-luc assay. Thus, the concentrations of OC pesticides in F-2 did not appear to have accounted for the dioxin-like activity observed. This suggests the presence of unidentified and/or unknown, acid-stable, dioxin-like compounds in F-2. This study suggests that in vitro bioassays are useful in assessing the contamination of mussels collected from coastal marine locations.

DNA-RNA chimeric hammerhead ribozyme to transforming growth factor-beta(1) mRNA inhibits the exaggerated growth of vascular smooth muscle cells from spontaneously hypertensive rats

OBJECTIVE

The purpose of this study was to develop DNA-RNA chimeric hammerhead ribozyme against transforming growth factor-beta(1) (TGF-beta(1)) mRNA as a gene therapy agent for arterial proliferative diseases.

METHODS

A 38-base hammerhead ribozyme against rat TGF-beta(1) mRNA, to produce cleavage at the GUC sequence at nucleotide 825 according to the secondary structure of rat TGF-beta(1) mRNA was designed. To enhance its stability, we synthesized a DNA-RNA chimeric ribozyme with two phosphorothioate linkages at the 3'-terminal. We also synthesized a mismatch ribozyme with single base change in the catalytic loop region as a control. These ribozymes were delivered into rat vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats by lipofectin-mediated transfection, and their biological effects were investigated.

RESULTS

According to in vitro cleavage studies, the synthetic ribozyme can cleave the synthetic substrate RNA into two RNA fragments. Chimeric ribozyme significantly inhibited DNA synthesis in VSMC from SHR but not in cells from WKY rats. Mismatch ribozyme showed only a little effect on growth of VSMC from SHR. Chimeric ribozyme significantly inhibited proliferation of VSMC from SHR; in contrast, the proliferation of VSMC from WKY rats was significantly increased by this chimeric ribozyme. Mismatch ribozyme did not affect proliferation of VSMC from either rat strain. Chimeric hammerhead ribozyme to rat TGF-beta(1) dose-dependently inhibited TGF-beta(1) mRNA expression detected by reverse transcription and polymerase chain reaction analysis in VSMC from both rat strains. Chimeric hammerhead ribozyme to rat TGF-beta(1) also dose-dependently inhibited TGF-beta(1) protein production detected by Western blot analysis.

CONCLUSIONS

The present results demonstrated that our designed DNA-RNA chimeric hammerhead ribozyme to TGF-beta(1) mRNA might be a useful gene therapy agent for hypertensive vascular diseases.

Prevalence and severity of symptoms in terminal cancer patients: a study in Taiwan

This paper reports a prospective study conducted between September 1997 and July 1998 in 232 consecutive patients with terminal cancer. A structured data collection form was used daily to evaluate symptoms, which were analyzed at the time of admission, 1 week after admission and 48 h before death. Terminal cancer patients in this study were polysymptomatic. There were no statistically significant differences in the prevalence of most symptoms with the primary site of cancer. The majority of symptoms improved at the end of the 1st week after admission, but many symptoms worsened just before death. The high prevalence of symptoms and lack of significant difference among primary tumor sites may be related to shorter survival times caused by late referral, which is common in Taiwan.

Phenotypic modulation by fibronectin enhances the angiotensin II-generating system in cultured vascular smooth muscle cells

We previously demonstrated that homogeneous cultures of vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats produce angiotensin II (Ang II) in response to increases in the levels of angiotensinogen, cathepsin D, and angiotensin-converting enzyme (ACE). The change of VSMCs from the contractile to the synthetic phenotype increased the amount of synthetic organelles, resulting in the production of proteases and growth factors. To evaluate the contribution of the synthetic phenotype to the generation of Ang II, we examined the effect of fibronectin (FN), which reportedly induces the synthetic phenotype, on the Ang II-generating system in VSMCs. Cultured VSMCs from Wistar-Kyoto rats were incubated with an active fragment of FN, Arg-Gly-Asp-Ser, for 24, 48, or 72 hours after synchronization of the cell cycle with 0. 2% calf serum for 48 hours. Immunofluorescence and protein levels of alpha-smooth muscle (SM) actin and expression of SM22alpha mRNA, apparent in the contractile phenotype, were suppressed by FN, whereas expression of matrix Gla mRNA and osteopontin mRNA and protein, apparent in the synthetic phenotype, was increased. FN (1 to 1000 microg/mL) dose-dependently increased DNA synthesis in the VSMCs, which was inhibited by the Ang II type 1 receptor antagonist CV-11974. Ang II-like immunoreactivity as determined by radioimmunoassay was significantly increased in conditioned medium from the VSMCs. In addition, mRNA for the Ang II-generating proteases cathepsin D and ACE was increased by FN. Expression of transforming growth factor-beta1, platelet-derived growth factor A-chain, and basic fibroblast growth factor mRNAs was also increased by FN. These results indicate that the changes accompanying the alteration to the synthetic phenotype in homogeneous cultures of VSMCs increase expression of proteases such as cathepsin D and ACE, which then produce Ang II, and that these changes increase expression of growth factors that then induce growth of VSMCs.

Polyoxygenated bipyridine, pyrrolylpyridine, and bipyrrole alkaloids from Speranskia tuberculata

Five novel polyoxygenated alkaloids, speranculatines A-C (3-5), speranskilatine A (6), and speranberculatine A (7), have been isolated from Speranskia tuberculata. Compounds 3-5, 6, and 7, have bipyridine, pyrrolylpyridine, and bipyrrole skeletons, respectively. This is the first time that these three alkaloid structural types have been reported. The structures of 3-7 were elucidated by spectroscopic methods, including 2D NMR techniques and X-ray crystallographic analysis.

Effect of methylene methylimino linkage of antisense oligonucleotide to the platelet-derived growth factor A-chain on growth of vascular smooth muscle cells from spontaneously hypertensive rats

Spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells show exaggerated growth and increased expression of platelet-derived growth factor (PDGF) A-chain mRNA. We examined the effect of methylene methylimino linkage of antisense oligodeoxynucleotide, a novel modification of antisense oligodeoxynucleotide designed to increase nuclease resistance, to PDGF A-chain on the exaggerated growth of vascular smooth muscle cells from SHR. Methylene methylimino-linked oligodeoxynucleotide provided complete resistance against S1 nuclease. Methylene methylimino linkage of antisense oligodeoxynucleotide to PDGF A-chain resulted in a rapid inhibition of basal DNA synthesis of vascular smooth muscle cells from SHR. This inhibition was much greater than that produced by phosphorothioate linkage of antisense oligodeoxynucleotide to PDGF A-chain. The methylene methylimino linkage of antisense oligodeoxynucleotide to PDGF A-chain may prove useful in the treatment of arterial proliferative diseases including hypertension.

Angiotensin II upregulates transforming growth factor-beta type I receptor on rat vascular smooth muscle cells

Angiotensin II (Ang II) and transforming growth factor-beta (TGF-beta) modulate cell growth and metabolism. Our objective was to evaluate the effect of Ang II on the characteristics and expression of TGF-beta receptors on vascular smooth muscle cells (VSMC) from Wistar-Kyoto rats. The addition of TGF-beta1 elicited a biphasic response on DNA synthesis in cultured VSMC in the absence of Ang II, but TGF-beta1 did not stimulate DNA synthesis in the presence of Ang II. TGF-beta binding data showed that Ang II increased the specific binding of 125I-TGF-beta1 by enhancing the expression of lower affinity receptors and increasing the number of binding sites. Ang II alone did not stimulate DNA synthesis in these cultures. However, Ang II significantly stimulated DNA synthesis after the inhibition of endogenous TGF-beta with a neutralizing antibody. The DNA synthesis stimulated by phorbol ester milisterol (PMA) was not affected by the TGF-beta neutralizing antibody. Affinity labeling data revealed receptor-ligand complexes of 280, 85, and 70 kDa, corresponding to TGF-beta type III, II, and I receptors, respectively. Incubation of VSMC with Ang II but not with PMA markedly increased the expression of the TGF-beta type I receptor. Reverse transcription and polymerase chain reaction data also indicated that Ang II, but not PMA, significantly increased the expression of TGF-beta type I receptor mRNA. Results suggest that Ang II increases the binding of TGF-beta with upregulation of TGF-beta type I receptor via a C-kinase-independent pathway. The enhanced expression of the TGF-beta type I receptor may counteract Ang II-promoted growth of VSMC.

Retirement planning and long-term risk

Many defined contribution plan participants have available to them various measures of short-term risk. However, some of these participants don't understand that reducing short-term risk comes at the cost of increasing the risk of not reaching their retirement income goal. This article looks at the relationship between short- and long-term risk and their impact on retirement savings.

Low dose of eicosapentaenoic acid inhibits the exaggerated growth of vascular smooth muscle cells from spontaneously hypertensive rats through suppression of transforming growth factor-beta

OBJECTIVE

To evaluate effects of eicosapentaenoic acid (EPA), an n-3 polyunsaturated fatty acid, on the exaggerated growth of vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR).

DESIGN

Cultured VSMC were prepared by an explant method from thoracic aortas in 8-week-old male Wistar-Kyoto (WKY)/Izumo rats and SHR/Izumo. Effects of EPA on basal DNA synthesis, expression of growth factors and cyclin-dependent kinase 2 (cdk2) activity were examined in VSMC from WKY rats and SHR.

METHODS

The cell cycles were synchronized with serum deprivation, then DNA synthesis in VSMC was measured by [3H]-thymidine incorporation. Fatty acid composition of the phospholipid fraction in VSMC was measured by gas chromatography. Expression of platelet-derived growth factor (PDGF) A-chain, transforming growth factor (TGF)-beta1 and basic fibroblast growth factor (bFGF) mRNAs was evaluated by reverse-transcription and polymerase chain reaction analysis. Cdk2 activity was determined by autoradiography after polyacrylamide gel electrophoresis of VSMC extracts that had been immunoprecipitated with anti-cdk2 antibody and protein A sepharose, and then incubated with 32P-ATP and histone H1.

RESULTS

High concentrations (40 and 80 micromol/I) of EPA significantly inhibited basal DNA synthesis in VSMC from both rat strains. Low dose (20 micromol/l) of EPA significantly inhibited basal DNA synthesis in VSMC from SHR, whereas the same dose of EPA stimulated DNA synthesis in VSMC from WKY rats. In analysis of fatty acid composition, low dose of EPA was considerably incorporated in VSMC. Low dose of EPA significantly inhibited angiotensin II- and phorbol ester milisterol-stimulated DNA synthesis in VSMC from both rat strains, whereas EPA did not affect PDGF-AA-stimulated DNA synthesis in VSMC from either rat strain. Low dose of other polyunsaturated fatty acids such as docosahexaenoic acid, arachidonic acid and linoleic acid did not significantly affect basal DNA synthesis in VSMC from either strain. Low dose of EPA significantly inhibited expression of TGF-beta1 mRNA in VSMC from SHR, whereas EPA did not affect expression of PDGF A-chain and bFGF mRNAs in VSMC from SHR. Cdk2 activity in VSMC from SHR was higher than that from WKY rats. Low dose of EPA inhibited cdk2 activity in VSMC from SHR, whereas it stimulated the activity in VSMC from WKY rats.

CONCLUSION

Low dose of EPA exerted specific inhibition of the exaggerated growth of VSMC from SHR through the suppression of TGF-beta.

Metabolism of methyl tert-butyl ether and other gasoline ethers by human liver microsomes and heterologously expressed human cytochromes P450: identification of CYP2A6 as a major catalyst

To reduce the production of carbon monoxide and other pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Previously, we demonstrated that human liver is active in metabolizing MTBE to tert-butyl alcohol (TBA) and that cytochrome P450 (CYP) enzymes play a critical role in the metabolism of MTBE. The present study demonstrates that human liver is also active in the oxidative metabolism of ETBE and TAME. A large interindividual variation in metabolizing these gasoline ethers was observed in 15 human liver microsomal samples. The microsomal activities in metabolizing MTBE, ETBE, and TAME were highly correlated among each other (r, 0.91-0. 96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the liver microsomes showed that the highest degree of correlation was with human CYP2A6 (r, 0. 90-0.95), which is constitutively expressed in human livers and known to be polymorphic. CYP2A6 displayed the highest turnover number in metabolizing gasoline ethers among a battery of human CYP enzymes expressed in human B-lymphoblastoid cells. Kinetic studies on MTBE metabolism with three human liver microsomes exhibited apparent Km values that ranged from 28 to 89 microM and the V(max) values from 215 to 783 pmol/min/mg, with similar catalytic efficiency values (7.7 to 8.8 microl/min/mg protein). Metabolism of MTBE, ETBE, and TAME by human liver microsomes was inhibited by coumarin, a known substrate of human CYP2A6, in a concentration-dependent manner. Monoclonal antibody against human CYP2A6 caused a significant inhibition (75% to 95%) of the metabolism of MTBE, ETBE, and TAME in human liver microsomes. Taken together, these results clearly indicate that in human liver, CYP2A6 is the major enzyme responsible for the metabolism of MTBE, ETBE, and TAME.

Contribution of synthetic phenotype on the enhanced angiotensin II-generating system in vascular smooth muscle cells from spontaneously hypertensive rats

OBJECTIVE

We have demonstrated that cultured vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR), but not from normotensive Wistar-Kyoto (WKY) rats, produce angiotensin II (Ang II) in a homogeneous culture with increased levels of angiotensinogen, cathepsin D and angiotensin converting enzyme (ACE) at early passages. In the current study, we investigated how changes in the cell phenotype affect the Ang II-generating system and the growth of VSMC from SHR.

DESIGN AND METHODS

We evaluated basal DNA synthesis by [3H]thymidine incorporation, immunofluorescence of alpha-smooth muscle (SM) actin, mRNA expression of phenotype markers such as SM22alpha appeared by contractile phenotype, Ang II-generating system components and growth factors by reverse transcription and polymerase chain reaction analysis, and Ang II levels by radioimmunoassay in quiescent VSMC from WKY/Izumo rats and SHR/Izumo at passages 4, 8 and 12.

RESULTS

Basal DNA synthesis in VSMC from WKY rats increased with increasing passage number, whereas in cells from SHR it was markedly higher at early passages and was not affected by the passages. At early passage numbers, immunofluorescence of alpha-SM actin was stronger in VSMC from WKY rats than in cells from SHR, but decreased after several passages. Expression of SM22alpha mRNA was higher in VSMC from WKY rats than in cells from SHR at early passages, and decreased after several passages in cells from both rat strains. Expression of matrix Gla mRNA was higher in VSMC from SHR than in cells from WKY rats at early passage, and increased after several passages in cells from both rat strains. Ang II was not detected at early passages but increased in VSMC from WKY rats with increasing passage, whereas it was detected in VSMC from SHR at early passages and did not change with the passages. Expression of angiotensinogen mRNA was higher in VSMC from SHR than in cells from WKY rats, and was not affected by the passages. Expressions of cathepsin D and ACE mRNA were higher in VSMC from SHR than in cells from WKY rats at early passage, and were increased by the passages in VSMC from WKY rats. Expressions of transforming growth factor-beta1, platelet-derived growth factor A-chain, and basic fibroblast growth factor mRNA were significantly higher in VSMC from SHR than in cells from WKY rats, and were increased by the passages.

CONCLUSION

These data indicate that early in culture VSMC from SHR have the synthetic phenotype, whereas VSMC from WKY rats have the contractile phenotype which then changes to the synthetic phenotype after increased passage numbers, with increased expression of cathepsin D and ACE, which produce Ang II, and increased expression of Ang II-related growth factors, which induce the exaggerated growth observed in VSMC from SHR.

Acetone catabolism by cytochrome P450 2E1: studies with CYP2E1-null mice

Previous experiments in vitro have suggested that cytochrome P450 2E1 (CYP2E1) is involved in acetone catabolism by converting acetone to acetol and then to methylglyoxal, both intermediates in the gluconeogenic pathway. In the present study, CYP2E1-null mice were used to demonstrate the role of CYP2E1 in acetone catabolism in vivo. The blood acetone level in male CYP2E1-null mice was 3.3 +/- 0.9 microg/mL, which was similar to levels of their sex- and age-matched parental lineage strains C57BL/6N (2.3 +/- 0.2 microg/mL) and 129/Sv (3.5 +/- 0.3 microg/mL) mice (both are CYP2E1 wild-type). After fasting for 48 hr, the blood acetone levels in the CYP2E1 wild-type mice were increased by 2.5- to 4.4-fold, but that in the CYP2E1-null mice increased 28-fold. These results clearly demonstrate that CYP2E1 plays a vital role in the catabolism of acetone under fasting conditions.

Production of angiotensin II by homogeneous cultures of vascular smooth muscle cells from spontaneously hypertensive rats

Production of angiotensin II (Ang II) in spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells (VSMC) has now been investigated. A nonpeptide antagonist (CV-11974) of Ang II type 1 receptors inhibited basal DNA synthesis in VSMC from SHR, but it had no effect on cells from Wistar-Kyoto (WKY) rats. Ang II-like immunoreactivity, determined by radioimmunoassay after HPLC, was readily detected in conditioned medium and extracts of SHR-derived VSMC, whereas it was virtually undetectable in VSMC from WKY rats. Isoproterenol increased the amount of Ang II-like immunoreactivity in conditioned medium and extracts of SHR-derived VSMC, whereas the angiotensin-converting enzyme inhibitor delapril significantly reduced the amount of Ang II-like immunoreactivity in conditioned medium and extracts of these cells. Reverse transcription-polymerase chain reaction analysis revealed that the abundance of mRNAs encoding angiotensinogen, cathepsin D, and angiotensin-converting enzyme was greater in VSMC from SHR than in cells from WKY rats. The abundance of cathepsin D protein by Western blotting was greater in VSMC from SHR than in cells from WKY rats. Ang I-generating and acid protease activities were detected in VSMC from SHR, but not in cells from WKY rats. These results suggest that SHR-derived VSMC generate Ang II with increases in angiotensinogen, cathepsin D, and angiotensin-converting enzyme, which contribute to the basal growth. Production of Ang II by homogeneous cultures of VSMC is considered as a new mechanism of hypertensive vascular disease.