Intestinal Translocation of Live Porphyromonas gingivalis Drives Insulin Resistance

Periodontitis has been emphasized as a risk factor of insulin resistance-related systemic diseases. Accumulating evidence has suggested a possible "oral-gut axis" linking oral infection and extraoral diseases, but it remains unclear whether periodontal pathogens can survive the barriers of the digestive tract and how they play their pathogenic roles. The present study established a periodontitis mouse model through oral ligature plus Porphyromonas gingivalis inoculation and demonstrated that periodontitis aggravated diet-induced obesity and insulin resistance, while also causing P. gingivalis enrichment in the intestine. Metabolic labeling strategy validated that P. gingivalis could translocate to the gastrointestinal tract in a viable state. Oral administration of living P. gingivalis elicited insulin resistance, while administration of pasteurized P. gingivalis had no such effect. Combination analysis of metagenome sequencing and nontargeted metabolomics suggested that the tryptophan metabolism pathway, specifically indole and its derivatives, was involved in the pathogenesis of insulin resistance caused by oral administration of living P. gingivalis. Moreover, liquid chromatography-high-resolution mass spectrometry analysis confirmed that the aryl hydrocarbon receptor (AhR) ligands, mainly indole acetic acid, tryptamine, and indole-3-aldehyde, were reduced in diet-induced obese mice with periodontitis, leading to inactivation of AhR signaling. Supplementation with Ficz (6-formylindolo (3,2-b) carbazole), an AhR agonist, alleviated periodontitis-associated insulin resistance, in which the restoration of gut barrier function might play an important role. Collectively, these findings reveal that the oral-gut translocation of viable P. gingivalis works as a fuel linking periodontitis and insulin resistance, in which reduction of AhR ligands and inactivation of AhR signaling are involved. This study provides novel insight into the role of the oral-gut axis in the pathogenesis of periodontitis-associated comorbidities.

Bioinformatics-based design of a fusion vaccine with CTLA-4 variable region to combat Brucella

Brucellosis has become a global zoonotic disease, seriously endangering the health of people all over the world. Vaccination is an effective strategy for protection against Brucella infection in livestock in developed countries. However, current vaccines are pathogenic to humans and pregnant animals, which limits their use. Therefore, it is very important to improve the safety and immune protection of Brucella vaccine. In this study, different bioinformatics approaches were carried out to predict the physicochemical properties, T/B epitope, and tertiary structure of Omp2b and Omp31. Then, these two proteins were sequentially linked, and the Cytotoxic T lymphocyte associated antigen-4 (CTLA-4) variable region was fused to the N-terminal of the epitope sequence. In addition, molecular docking was performed to show that the structure of the fusion protein vaccine had strong affinity with B7 (B7-1, B7-2). This study showed that the designed vaccine containing CTLA-4 had high potency against Brucella, which could provide a reference for the future development of efficient brucellosis vaccines.

A generalized l 2,p-norm regression based feature selection algorithm

Feature selection is an important data dimension reduction method, and it has been used widely in applications involving high-dimensional data such as genetic data analysis and image processing. In order to achieve robust feature selection, the latest works apply the l 2 , 1 or l 2 , p -norm of matrix to the loss function and regularization terms in regression, and have achieved encouraging results. However, these existing works rigidly set the matrix norms used in the loss function and the regularization terms to the same l 2 , 1 or l 2 , p -norm, which limit their applications. In addition, the algorithms for solutions they present either have high computational complexity and are not suitable for large data sets, or cannot provide satisfying performance due to the approximate calculation. To address these problems, we present a generalized l 2 , p -norm regression based feature selection ( l 2 , p -RFS) method based on a new optimization criterion. The criterion extends the optimization criterion of ( l 2 , p -RFS) when the loss function and the regularization terms in regression use different matrix norms. We cast the new optimization criterion in a regression framework without regularization. In this framework, the new optimization criterion can be solved using an iterative re-weighted least squares (IRLS) procedure in which the least squares problem can be solved efficiently by using the least square QR decomposition (LSQR) algorithm. We have conducted extensive experiments to evaluate the proposed algorithm on various well-known data sets of both gene expression and image data sets, and compare it with other related feature selection methods.

[CFTR gene variations and phenotypes in seven children]

Objective: To analyze the cystic fibrosis transmembrane conductance regulator (CFTR) gene variations and phenotypes in 7 Chinese children. Methods: In this retrospective study, the data of 7 children with CFTR gene variations admitted to Children's Hospital of Chongqing Medical University from December 2013 to October 2020 were extracted. The general information, clinical manifestations, gene variations, diagnosis and treatment were summarized. Results: Among the 7 children, 2 were males and 5 were females, aged 5.2(0.5-11.3) years. Main clinical manifestations included malnutrition (5 cases), recurrent respiratory infection (4 cases), bronchiectasis (3 cases), steatorrhea (3 cases), vomiting in infancy (2 cases), liver cirrhosis (2 cases), meconium ileus (1 case), metabolic alkalosis and hypochloremia (1 case). A total of 15 variations were found by whole exon sequencing and Sanger sequencing, among which 3 were newly discovered, and 7 were missense mutations. Four children were diagnosed as CF, and the other 3 were diagnosed as CFTR related disease (CFTR-RD). Compared with CF patients, the pancreatic insufficiency and typical CF lung disease were relatively mild in CFTR-RD patients. After treatment, 6 children were clinically improved, while the rest one withdrew treatment due to critical pulmonary infection and disturbance of water-electrolyte metabolism. Conclusions: The loci and phenotypes of CFTR gene variants vary hugely and the pathogenicity of some variations are not clear. Whole exon sequencing can facilitate the identification of CF-and CFTR-RD-causing variaions. For the cases not compatible with CF, CFTR-RD should be considered and evaluated by timely gene detection, so as to carry out appropriate long term management.

Microsurgical treatment for spinal epidural angiolipomas

Spinal epidural angiolipomas are rare lesions composed of mature lipomatous and angiomatous elements. In this paper, the authors review a surgical series of ten patients with epidural angiolipomas. All patients had performed preoperative and postoperative magnetic resonance imaging. The diagnosis of angiolipoma was based on pathology. All the follow-up data were obtained during office visits. There were 5 males and 5 females with a mean age of 53.6 years. One tumor was located in the cervicothoracic, six in the thoracic, and three in the lumbar spine. The most common symptom was progressive motor deficit. Gross total resection of the tumor was achieved in nine cases, and subtotal resection was obtained in one case. No recurrence or regrowth of the residual tumor was observed during a follow-up period of 50.8 months. At the last follow-up, 90% of patients experienced improvement in the neurological function. Epidural angiolipomas are benign but clinically progressive lesions. Early surgery should be performed to prevent irreversible neurological deficits. Postoperative radiotherapy is not recommended. The risk of long-term recurrence/regrowth of the lesions is low, and a good clinical outcome after total or subtotal removal can be expected.

Exogenous 6-benzyladenine application affects root morphology by altering hormone status and gene expression of developing lateral roots in Malus hupehensis

Malus hupehensis is an extensively used apple rootstock in China. In the current study, M. hupehensis seedlings were treated with exogenous 2.2 µm 6-benzyladenine (6-BA) so as to investigate the mechanism by which 6-BA affects lateral root development. The results indicate that 6-BA treatment promotes elongation and thickening of both root and shoot in M. hupehensis, but reduces the number of lateral roots, as well as reducing the auxin level after 6-BA treatment. Moreover, MhAHK4, MhRR1 and MhRR2 were also significantly up-regulated in response to 6-BA treatment. Expression levels of auxin synthesis- and transport-related genes, such as MhYUCCA6, MhYUCCA10, MhPIN1 and MhPIN2, were down-regulated, which corresponds with lower auxin levels in the 6-BA-treated seedlings. A negative regulator of auxin, MhIAA3, was induced by 6-BA treatment, leading to reduced expression of MhARF7 and MhARF19 in 6-BA-treated seedlings. As a result, expression of MhWOX11, MhWOX5, MhLBD16 and MhLBD29 was blocked, which in turn inhibited lateral root initiation. In addition, a lower auxin level decreased expression of MhRR7 and MhRR15, which repressed expression of key transcription factors associated with root development, thus inhibiting lateral root development. In contrast, 6-BA treatment promoted secondary growth (thickening) of the root by inducing expression of MhCYCD3;1 and MhCYCD3;2. Collectively, the changes in hormone levels and gene expression resulted in a reduced number of lateral roots and thicker roots in 6-BA-treated plants.

Two linked TBXT (brachyury) gene polymorphisms are associated with the tailless phenotype in fat-rumped sheep

T‐box transcription factor T (TBXT), encoding the brachyury protein, is an embryonic nuclear transcription factor involved in mesoderm formation and differentiation. Previous studies indicate that TBXT mutations are responsible for the tailless or short‐tailed phenotype of many vertebrates. To verify whether the tailless phenotype in fat‐rumped sheep is associated with TBXT mutations, exon 2 of the TBXT gene for 301 individuals belonging to 13 Chinese and Iranian sheep breeds was directly sequenced. Meanwhile, 380 samples were used to detect the genotypes of the candidate variations by mapping to their reads databases in the Sequence Read Archive repository of GenBank. The results showed that one missense mutation, c.334G>T (GGG>TGG) with a completely linked synonymous variant c.333G>C (CCG>CCC) was found to be associated with the ‘tailless’ characteristic in typical fat‐rumped sheep breeds. The c.334G>T transversion led to the conversion of glycine to tryptophan at the 112th amino acid in the T‐box domain of the brachyury protein. In addition, crossbreeding experiments for long‐tailed and tailless sheep showed that CT/CT allele of nucleotides (nt) 333 and 334, a recessive mutation, would cause sheep tails to be shorter, suggesting that these two linked variants at nucleotides 333 and 334 in TBXT are probably causative mutations responsible for the tailless phenotype in sheep.

Vitamin A maintains the airway epithelium in a murine model of asthma by suppressing glucocorticoid-induced leucine zipper

BACKGROUND

The effects of glucocorticoids (GCs) on the repair of the airway epithelium in asthma are controversial, and we previously reported that the GC dexamethasone (Dex) inhibits the repair of human airway epithelial cells and that this process is mediated by glucocorticoid-induced leucine zipper (GILZ) through MAPK-ERK signaling in vitro. Vitamin A (VA) is involved in the regulation of the MAPK-ERK pathway but has not been widely supplied during asthma treatment. It is unclear whether VA attenuates the negative regulation of GILZ on the MAPK-ERK pathway and maintains airway epithelium integrity during asthma treatment.

METHODS

Female BALB/c mice were sensitized and challenged with ovalbumin (OVA) and subsequently treated with Dex, VA or intranasal inhalation of adenovirus sh-GILZ vectors. Indexes of airway epithelium integrity, including pathological alterations, pulmonary EGFR expression and airway hyperresponsiveness (AHR), were then measured. The expression of GILZ and key components of activated MAPK-ERK signals (p-Raf-1, p-MEK, and p-Erk1/2) were also detected.

RESULTS

Dex failed to relieve OVA-induced asthma airway epithelium injury, as assessed through H&E staining, EGFR expression and AHR. Moreover, in the OVA-challenged mice treated with Dex, GLIZ expression was increased, whereas the ratios of p-Raf-1/Raf-1, p-MEK/MEK and p-Erk1/2/Erk1/2 were significantly decreased. Further study indicated that GILZ expression was decreased and that the ratios of p-Raf-1/Raf-1, p-MEK/MEK and p-Erk1/2/Erk1/2 were up-regulated in the GILZ-silenced OVA-challenged mice and VA-fed OVA-challenged mice, independent of Dex treatment. The airway epithelium integrity of the OVA-challenged mice was maintained by treatment with both VA and Dex.

CONCLUSIONS

Vitamin A maintained the Dex-treated asthma airway epithelium via the down-regulation of GILZ expression and the activation MAPK-ERK signaling, and these effects might contribute to improving the effects of GC therapeutics on asthma.

Apical stress distribution under vertical compaction of gutta-percha and occlusal loads in canals with varying apical sizes: a three-dimensional finite element analysis

AIM

To investigate and compare the effects of two apical canal instrumentation protocols on apical stress distribution at the root apex under vertical compaction of gutta-percha and occlusal loads using finite element analysis.

METHODOLOGY

Three finite element analysis models of a mandibular first premolar were reconstructed: an original canal model, a size 35, .04 taper apical canal enlargement model and a Lightspeed size 60 apical canal enlargement model. A 15 N compaction force was applied vertically to the gutta-percha 5 mm from the apex. A 175 N occlusal load in two directions (vertical and 45° to the longitudinal axis of the tooth) was simulated. Stresses in the apical 2 mm of the root were calculated and compared among the three models.

RESULTS

Under vertical compaction, stresses in the apical canal instrumented by Lightspeed size 60 (maximal 3.3 MPa) were higher than that of the size 35, .04 taper model (maximal 1.3 MPa). In the case of the two occlusal forces, the Lightspeed size 60 apical enlargement was associated with the greatest stress distribution in the apical region. The greatest stress and the most obvious stress difference between the models appeared at the tip of the root when occlusal and vertical compaction loads were applied.

CONCLUSIONS

Apical enlargement caused stress distribution changes in the apical region of roots. The larger apical size led to higher stress concentration at the root apex.

Characterizations, relationship, and potential sources of outdoor and indoor particulate matter bound polycyclic aromatic hydrocarbons (PAHs) in a community of Tianjin, Northern China

Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. However, because there are unsubstantial data on indoor and outdoor particulate PAHs, efforts in assessing inhalation exposure and cancer risk to PAHs are limited in China. This study measured 12 individual PAHs in indoor and outdoor environments at 36 homes during the non-heating period and heating period in 2009. Indoor PAH concentrations were comparable with outdoor environments in the non-heating period, but were lower in the heating period. The average indoor/outdoor ratios in both sampling periods were lower than 1, while the ratios in the non-heating period were higher than those in the heating period. Correlation analysis and coefficient of divergence also verified the difference between indoor and outdoor PAHs, which could be caused by high ventilation in the non-heating period. To support this conclusion, linear and robust regressions were used to estimate the infiltration factor to compare outdoor PAHs to indoor PAHs. The calculated infiltration factors obtained by the two models were similar in the non-heating period but varied greatly in the heating period, which may have been caused by the influence of ventilation. Potential sources were distinguished using a diagnostic ratio and a mixture of coal combustion and traffic emission, which are major sources of PAHs.

Patient preference: a comparison of electronic patient-completed questionnaires with paper among cancer patients

In this study, we compared cancer patients preference for computerised (tablet/web-based) surveys versus paper. We also assessed whether the understanding of a cancer-related topic, pharmacogenomics is affected by the survey format, and examined differences in demographic and medical characteristics which may affect patient preference and understanding. Three hundred and four cancer patients completed a tablet-administered survey and another 153 patients completed a paper-based survey. Patients who participated in the tablet survey were questioned regarding their preference for survey format administration (paper, tablet and web-based). Understanding was assessed with a 'direct' method, by asking patients to assess their understanding of genetic testing, and with a 'composite' score. Patients preferred administration with tablet (71%) compared with web-based (12%) and paper (17%). Patients <65 years old, non-Caucasians and white-collar professionals significantly preferred the computerised format following multivariate analysis. There was no significant difference in understanding between the paper and tablet survey with direct questioning or composite score. Age (<65 years) and white-collar professionals were associated with increased understanding (both P = 0.03). There was no significant difference in understanding between the tablet and print survey in a multivariate analysis. Patients overwhelmingly preferred computerised surveys and understanding of pharmacogenomics was not affected by survey format.

First Report of Sclerotinia Stem Rot of Canola Caused by Sclerotinia sclerotiorum in Texas

During the past several years, canola (Brassica napus L.) has been grown experimentally in different areas of Texas to evaluate its potential as a crop, particularly for use as a biofuel source. In early April 2007, symptoms typical of Sclerotinia stem rot were observed in a canola variety trial that was flowering in Wharton County, Texas. Stems had white mycelia growing on the outside, or a bleached appearance, near the soil surface and plants were lodging. Inside bleached stems, there were spherical to cylindrical, black sclerotia that were 3 to 10 mm. Isolations from surface-disinfested stems onto potato dextrose agar (PDA) consistently yielded white, fluffy colonies with sclerotia typical of Sclerotinia sclerotiorum (Lib.) de Bary (1). Sequence analyses were conducted on two replicates of mycelium by extracting fungal DNA with the Qiagen DNeasy Plant Mini Kit (Valencia, CA). PCR amplification was performed using two primer sequences (92-4 AF377919: TCGCCTCAGAAGAATGTGC/AGCGGGTTACAAGGAGATGG; and 119-4 AF377925: GTAACAAGAGACCAAAATTCGG/TGAACGAGCTGTCATTCCC) (2) that have previously been used to characterize S. sclerotiorum (3). The BLAST search revealed that the sequences were 99 and 98% homologous with S. sclerotiorum Accession Nos. AF377919 and AF377925 over 376 and 377 bp of aligned sequence, respectively. Agar segments (1 cm²) from a 5-day-old culture grown on PDA were placed in the leaf axils of 15 2-month-old canola plants ('Wichita') growing in pots. Plants were placed in a humid chamber under fluorescent lights at 16 to 22°C. After 2 days, water soaking and necrosis occurred on petioles and stems adjacent to the inoculum, but not on plants treated with sterile PDA. S. sclerotiorum was consistently reisolated from symptomatic tissue plated on acidified PDA. The inoculations were repeated once with similar results. To our knowledge, this is the first report of Sclerotinia stem rot of canola in Texas. Currently, there is no significant canola production in Texas; however, interest in biofuels could lead to an increase in planted acres. Sclerotinia stem rot of canola could become a significant disease problem in areas of Texas where canola is planted as a winter crop. References: (1) L. M. Kohn. Phytopathology 69:881, 1979. (2) C. Sirjusingh and L. M. Kohn. Mol. Ecol. Notes 1:267, 2001. (3) J. E. Woodward et al. Plant Dis. 92:1468, 2008.

Antifungal Activity in Transgenic Peanut (Arachis hypogaea L.) Conferred by a Nonheme Chloroperoxidase Gene

A nonheme chloroperoxidase gene (cpo-p) from Pseudomonas pyrrocinia, a growth inhibitor of mycotoxin-producing fungi, was introduced into peanut via particle bombardment. The expression of the cpo-p gene is predicted to increase pathogen defense in peanut. Embryogenic peanut tissues were bombarded with gold particles coated with plasmid pRT66 carrying the cpo-p and hygromycin phosphotransferase (hph) genes, under the control of a double CaMV 35S and a single CaMV 35S promoter, respectively. Selection for hygromycin-resistant somatic embryos was performed on a liquid medium containing 10–20 mg/L hygromycin 3–4 days after bombardment. The integration and expression of the cpo-p gene was confirmed by Southern, Northern and Western blot analyses. In vitro bioassay using crude protein extracts from transgenic T0, T1, and T4 plants showed inhibition of Aspergillus flavus hyphal growth, which could translate to a reduction in aflatoxin contamination of peanut seed.

Repression of NFAT3 transcriptional activity by estrogen receptors

Nuclear factor of activated T cells 3 (NFAT3) activities have been implicated in many biological processes, such as breast cancer, cardiac hypertrophy, learning and memory, and adipocyte differentiation. However, how protein factors regulate NFAT3 transcriptional activity is poorly understood. Here, we report that regardless of estrogen, overexpression of estrogen receptor alpha and beta (ERalpha and ERbeta) suppresses NFAT3 transcriptional activity, whereas knockdown of endogenous ERalpha and ERbeta enhances the activity. Estrogen further enhances ER inhibition of NFAT3-dependent transcription. ERalpha and ERbeta interact with NFAT3 independently of the NFAT agonists phorbol myristate acetate (PMA) and ionomycin, and ERalpha is recruited to an NFAT3 target gene promoter. Phosphorylation of ERalpha at different sites differentially affects ERalpha modulation of NFAT3 transcriptional activity. These results suggest that ER may play a critical role in regulation of NFAT3 transcriptional activity.

Subinhibitory concentrations of cinnamaldehyde interfere with quorum sensing

AIMS

To investigate the effect of cinnamaldehyde (CA) on transcription from selected quorum sensing (QS) promoters.

METHODS AND RESULTS

The action of CA on QS was assayed using three E. coli green fluorescent protein (GFP) based bioreporters (two inducible and the other constitutive) and two Vibrio harveyi bioluminescent reporter strains. LuxR-mediated transcription from the P(luxI) promoter, which is induced by 3-oxo-C6-homoserine lactone (HSL), was reduced by 70 per cent following exposure to 200 micromol l(-1) CA (26 ppm). The bioluminescence of Vibrio harveyi BB886, which is mediated by 3-hydroxy-C4-HSL, was reduced by 55 per cent after exposure to 60 micromol l(-1) CA (8 ppm), and 100 micromol l(-1) CA (13 ppm) inhibited the bioluminescence of the autoinducer-2 (AI-2) responsive reporter strain V. harveyi BB170 by nearly 60 per cent. CA did not inhibit the growth of the bioreporter strains at these concentrations. CA had a minimal effect on LasR promoter activity, induced by 3-oxo-C12-HSL.

CONCLUSIONS

Low concentrations of CA were effective at inhibiting two types of acyl homoserine lactone mediated QS, and also autoinducer-2 mediated QS.

SIGNIFICANCE AND IMPACT OF STUDY

Because CA is widely used in the food and flavour industries, its potential to affect bacterial QS regulated processes should be recognized.

Colorimetric method for identifying plant essential oil components that affect biofilm formation and structure

The specific biofilm formation (SBF) assay, a technique based on crystal violet staining, was developed to locate plant essential oils and their components that affect biofilm formation. SBF analysis determined that cinnamon, cassia, and citronella oils differentially affected growth-normalized biofilm formation by Escherichia coli. Examination of the corresponding essential oil principal components by the SBF assay revealed that cinnamaldehyde decreased biofilm formation compared to biofilms grown in Luria-Bertani broth, eugenol did not result in a change, and citronellol increased the SBF. To evaluate these results, two microscopy-based assays were employed. First, confocal laser scanning microscopy (CLSM) was used to examine E. coli biofilms cultivated in flow cells, which were quantitatively analyzed by COMSTAT, an image analysis program. The overall trend for five parameters that characterize biofilm development corroborated the findings of the SBF assay. Second, the results of an assay measuring growth-normalized adhesion by direct microscopy concurred with the results of the SBF assay and CLSM imaging. Viability staining indicated that there was reduced toxicity of the essential oil components to cells in biofilms compared to the toxicity to planktonic cells but revealed morphological damage to E. coli after cinnamaldehyde exposure. Cinnamaldehyde also inhibited the swimming motility of E. coli. SBF analysis of three Pseudomonas species exposed to cinnamaldehyde, eugenol, or citronellol revealed diverse responses. The SBF assay could be useful as an initial step for finding plant essential oils and their components that affect biofilm formation and structure.

Acetylenic TACE inhibitors. Part 1. SAR of the acyclic sulfonamide hydroxamates

The SAR of a series of potent sulfonamide hydroxamate TACE inhibitors, all bearing a butynyloxy P1' group, was explored. In particular, compound 5j has excellent in vitro potency against isolated TACE enzyme and in cells, good selectivity over MMP-1 and MMP-9, and oral activity in an in vivo model of TNF-alpha production and a collagen-induced arthritis model.

[Immunoregulation of IL-2 in Trichinella-infected mice]

AIM

To study the immunoregulation of IL-2 in Trichinella-infected mice.

METHODS

Mice infected respectively with HL strain and AM strain larvae of Trichinella spiralis were treated i.p. with IL-2 from the second day postinfection for 3 days. Serum IgG antibody levels were determined by ELISA and the infection capacity was determined using reproductive capacity index (RCI).

RESULTS

In HL, higher dosage of IL-2 injection induced lower RCI and showed apparent anti-Trichinella effect. In AM, both low and high dose of IL-2 had no measurable effect on RCI, however, high dose of IL-2 reduced the infectivity of newborn larvae.

CONCLUSION

IL-2 exhibits apparent suppressive effect on the infectivity of T. spiralis of HL strain.

[Sensitivity and specificity of nested polymerase chain reaction in detecting Plasmodium vivax in infected mosquitoes]

AIM

To study the sensitivity and specificity of nested polymerase chain reaction for detection of Plasmodium vivax in infected mosquitoes.

METHODS

Two pairs of primers specific to small subunit ribosomal DNA of P. vivax were used to amplify the specific SSUrDNA 121 bp fragment of P. vivax for detecting P. vivax-infected mosquitoes with nested PCR.

RESULTS

Nested PCR could detect as few as 3 sporozoites in one mosquito or 1 infected mosquito mixed with a group of 99 normal ones. In contrast, no such specific 121 bp DNA band was detected in P. falciparum, P. cynomolgi, P. yoelii yoelii infected samples, nor in normal mosquito.

CONCLUSION

The nested PCR technique we established showed high sensitivity and specificity.

Gene expression in CD34(+) cells from normal bone marrow and leukemic origins

INTRODUCTION

To address the molecular regulation of hematopoiesis and the complex mechanism in leukemogenesis, we established the first catalogs of genes expressed in normal bone marrow and leukemia CD34(+) cells.

MATERIALS AND METHODS

CD34(+) cell cDNA libraries were constructed using mRNA from adult bone marrow and from a case of acute myeloid leukemia-M5 transformed from myelodysplastic syndrome (MDS-AML). Expressed sequence tags (ESTs) and full-length cDNAs were generated by sequencing and were annotated using bioinformatic tools.

RESULTS

From a total of 4142 ESTs obtained from normal bone marrow, 3424 meaningful tags were integrated into 1630 clusters, representing 622 known genes, 522 dbEST entries and 486 novel sequences. Out of 5382 ESTs from MDS-AML, 1985 clusters were produced based on the analysis of 4321 useful ESTs, including 711 known genes, 657 known ESTs and 617 novel sequences. Among 251 transcripts found in both bone marrow and MDS-AML EST datasets and those present in only one dataset, 58 showed statistically significant differences in EST copy numbers between the two tissues (P<0.05). Twenty putative full-length cDNAs for novel genes were also cloned from the MDS-AML library.

CONCLUSION

The distinct gene expression patterns in MDS-AML-CD34(+) cells as compared to normal control cells may contribute to the development and/or maintenance of the malignant phenotypes of leukemia cells.

DNA transfer by highly asymmetric somatic hybridisation in Medicago truncatula (+) Medicago rugosaand Medicago truncatula(+) Medicago scutellata

A regenerable line of Medicago truncatula(Jemalong 2HA) as a recipient species, was fused with the sexually incompatible species Medicago scutellataor Medicago rugosa.The treatments described maintain the chromosome number of the recipient but enable the transfer of small amounts of DNA of the donor species, probably by intergenomic recombination. Without a chromosome number-change fusion products can readily regenerate to produce fertile plants; and potentially a library with a diverse array of new genetic material. The selection of fused cells is based on treatment of the recipient cells with iodoacetamide (IOA), a non-regenerable donor, gamma-irradiation of the donor, and regeneration on a medium favouring the recipient. DNA transfer was demonstrated by amplified fragment length polymorphism (AFLP), Southern hybridisation and changed morphology.

Molecular cytogenetic characterization and clinical relevance of additional, complex and/or variant chromosome abnormalities in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is characterized by typical morphological manifestation, t(15;17) translocation and active response to all-trans retinoic acid (ATRA) in the great majority of patients. However, a subset of APL cases may present atypical phenotypic, cytogenetic or molecular features at different stages of the disease. The biological and clinical significance of these features sometimes remains obscure. In this study, 284 APL patients were cytogenetically analyzed and precise diagnosis was performed according to the molecular cytogenetic results. Twenty-six APL patients were identified as having additional, complex and/or variant chromosomal abnormalities at diagnosis or at relapse, 16 of them being further analyzed using fluorescence in situ hybridization (FISH) or chromosome painting (CP). Interestingly, some of these chromosomal aberrations were found to be associated with atypical morphology and/or drug response, indicating a genotype-phenotype correlation. Analysis of the complex karyotype may also allow a better understanding of the levels of cellular origin of the leukemogenesis. Examination of the remission induction and survival data showed that the presence of the additional/complex chromosome abnormalities was related to the prognosis in both primarily diagnosed and relapsed patients in this series.

Novel (4-piperidin-1-yl)-phenyl sulfonamides as potent and selective human beta(3) agonists

A series of novel (4-piperidin-1-yl)-phenyl sulfonamides was prepared and evaluated for their biological activity on the human beta(3)-adrenergic receptor (AR). Replacement of the 3,4-dihydroxyl group of the catechol moiety with 4-hydroxyl-3-methyl sulfonamide on the left-hand side of the compounds resulted in a number of potent full agonists at the beta(3) receptor. Modification of the right-hand side of the compounds by incorporation of a free carboxylic acid resulted in a few potent human beta(3) agonists with low affinities for beta(1)- and beta(2)-ARs. N-Alkyl substitution on the 4-piperidin-1-yl-phenylamine further increased the beta(3) potency while maintaining the selectivity. For example, sulfonamide 48 is a potent full beta(3) agonist (EC(50)=0.004 microM, IA=1.0) with > 500-fold selectivity over beta(1)- and beta(2)-ARs.

Studies on the clinical efficacy and pharmacokinetics of low-dose arsenic trioxide in the treatment of relapsed acute promyelocytic leukemia: a comparison with conventional dosage

Twenty cases of patients with relapsed acute promyelocytic leukemia (APL) were entered into this study for evaluating the clinical efficacy and pharmacokinetics of low-dose arsenic trioxide (As2O3). As2O3 was given at a daily dose of 0.08 mg/kg intravenously for 28 days. Pharmacokinetic study was carried out in eight patients. 16/20 (80%) patients achieved CR. The occurrence of some toxic events including gastrointestinal disturbance, facial edema and cardiac toxicity seemed reduced in the low-dose group than those in the standard-dose group. Differentiation changes were observed in peripheral blood, as well as in bone marrow (BM). Pharmacokinetic study showed that the plasma concentration increased soon after administration of As2O3 with the peak values of 1.535-3.424 micromol/l. After infusion, the plasma concentration was around 0.1-0.5 micromol/l. The arsenic concentration of the plasma of BM aspirates 24 h after administration in five patients was close to the level needed for differentiation-inducing effect. The estimated 2-year OS and RFS were 61.55+/-15.79% and 49.11+/-15.09% respectively, with no difference as compared with those in patients treated with conventional dose (P = 0.2865 and 0.7146, respectively). In conclusion, we demonstrated that low-dose As2O3 had the same effect as the conventional dosage and the mechanism of low-dose arsenic seemed to primarily induce differentiation of APL cells.

Nested polymerase chain reaction in detection of Plasmodium vivax sporozoites in mosquitoes

OBJECTIVE

To detect malaria DNA in mosquitoes.

METHODS

A nested polymerase chain reaction (nested PCR) procedure which amplifies a 121 bp DNA of a SSUrRNA gene specific to Plasmodium vivax was used.

RESULTS

In laboratory-infected mosquitoes, nested PCR could detect as few as 3 sporozoites or 1 infected mosquito mixed in a group of 99 normal ones. Furthermore, no specific 121 bp band was seen with DNA templates from other malaria parasites or negative mosquitoes.

CONCLUSION

Sensitivity and specificity obtained indicated an advantage of the nested PCR over DNA probes or direct PCR for the detection of Plasmodium vivax sporozoites in mosquitoes with low-grade parasitic infections.

Feasibility and clinical significance of real-time quantitative RT-PCR assay of PML-RARalpha fusion transcript in patients with acute promyelocytic leukemia

INTRODUCTION

To study the relationship between the expression level of the PML-RARalpha fusion transcripts and the clinical status and efficiency of the therapy in acute promyelocytic leukemia (APL) patients, we applied a very sensitive and specific real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR) system to quantify the dose of PML-RARalpha fusion transcripts in a series of APL patients at distinct disease stages.

MATERIALS AND METHODS

A total of 31 APL patients (19 males and 12 females; aged from 8 to 74 years) from eight hospitals in Shanghai were analysed. Real-time Quantitative RT-PCR was used to measure the normalized dose (DoseN) of PML-RARalpha fusion transcripts.

RESULTS

A wide range of PML-RARalpha DoseN above 1 x 10(3) was noted in 25 newly diagnosed patients. PML-RARalpha DoseN was significantly decreased after remission induction with ATRA, ATRA/chemotherapy or As2O3 and further reduced after consolidation. The fact that all patients with long disease free survival had a constantly low PML-RARalpha DoseN below 2 x 10(2) and a higher level predicted impending relapse suggests that this value could serve as a 'threshold' for molecular remission. PML-RARalpha DoseN was also of prognostic value in a group of relapsed patients, since good response to As2O3 reinduction was accompanied by a remarkable reduction of fusion transcript level, whereas patients with high PML-RARalpha Dose(N) after the second CR tended to relapse again rapidly.

CONCLUSION

These results confirm that real-time RT-PCR assay for PML-RARalpha transcripts in APL patients is useful in reflecting leukemic burden, assessing response to treatment and indicating the ultimate clinical outcome or curability of disease.

Characterization of enterovirus isolates from patients with heart muscle disease in a selenium-deficient area of China

An association of enterovirus infection with endemic cardiomyopathy (Keshan disease [KD]) and outbreaks of myocarditis in selenium-deficient rural areas of southwestern China has been established. Enteroviruses have been isolated from patients with KD or during outbreaks of myocarditis in last two decades. Six of these isolates grew readily in cell lines (Vero or HEp-2) and were investigated by a novel molecular typing method apart from serotyping and pathogenicity. A neutralization assay identified two isolates from KD as coxsackievirus serotype B2 (CVB2) and two isolates from myocarditis as coxsackievirus serotype B6 (CVB6) but failed to type the remaining two isolates, also from myocarditis. Direct nucleotide sequencing of reverse transcription-PCR products amplified from the 5' nontranslated region (5'NTR) of these viruses confirmed that they belong to a phylogenetic cluster consisting of coxsackie B-like viruses, including some echovirus serotypes. Sequence analysis of the coding region for viral capsid protein VP1 showed that two isolates serotyped as CVB2 have the highest amino acid sequence homology with CVB2 and that the remaining four isolates, two CVB6 and the two unknown serotypes, are most closely related to the sequence of CVB6. Sequences among these isolates varied from 82.3 to 99% in the 5'NTR and from 69 to 99% in VP1, indicating no cross contamination. The pathogenicity of these viruses in adult and suckling mice was assessed. None caused pathologic changes in the hearts of adult MF-1 or SWR mice, although pancreatitis was evident. However, the four CVB6-like viruses caused death in suckling mice, similar to a virulent coxsackievirus group B3 laboratory strain. In conclusion, the sequence data confirm that coxsackievirus group B serotypes are predominant in the region in which KD is endemic and may be the etiological agents in outbreaks of myocarditis. VP1 genotyping of enteroviruses is accurate and reliable. Animal experiments indicate that isolates may differ in pathogenicity.

High prevalence of enteroviral genomic sequences in myocardium from cases of endemic cardiomyopathy (Keshan disease) in China

OBJECTIVE

To verify the aetiological involvement of enterovirus and identify the viral genomic sequences in Keshan disease.

DESIGN

Formalin fixed, paraffin embedded myocardial necropsy tissue samples were collected in Keshan disease endemic regions. Fourteen cases with a histologically confirmed diagnosis of subacute or chronic Keshan disease were studied. Control tissue included 10 samples of myocardium from cases of cerebral trauma and one from accidental acid intoxication. One sample from a case of enteroviral myocarditis was used as a positive control. The presence of viral genomic RNA was investigated using an established reverse transcription nested polymerase chain reaction (PCR) coupled with direct nucleotide sequencing. Further investigations of PCR positive samples included in situ antigen detection or hybridisation to confirm positive results.

RESULTS

Nine of 14 myocardial samples from Keshan disease cases and the positive control were positive for the enteroviral RNA. All the controls were negative. Six of the PCR positive samples were investigated further by in situ enteroviral antigen or RNA detection and all were positive. DNA sequencing of six representative PCR products confirmed that they were homologous to the 5' non-translated region of enteroviral genomic RNA. Five had highest homology to coxsackievirus B genotypes and one was identical to poliovirus type 3.

CONCLUSIONS

These results support an aetiological role for enteroviral infection in Keshan disease. Nucleotide sequence data suggest that coxsackievirus B or coxsackie B like viruses are often involved in Keshan disease.

Two cases of AML (M2) with a t(8;19)(q22;q13): a new cytogenetic variant

"Simple" variants of the t(8;21) translocation involving chromosome 8 and a chromosome other than number 21 are rare. To our knowledge, only t(3;8)(q29;q22), t(8;11)(q22;q13), t(8;16)(q22;q24), t(8;20)(q22;p13), and t(8;22) have been reported in the literature. This paper describes for the first time two patients with acute myelogenous leukemia with a consistent t(8;19)(q22;q13) translocation. Their myelograms were compatible with the FAB-M2 subtype. The blasts from case 2 expressed CD34, CD33, CD13, and CD19. Karyotype analyses were performed on bone marrow cells using R- and G-banding at presentation. A t(8;19)(q22;q13) translocation was found in 28/30 metaphases for case 1 and in 23/25 metaphases for case 2. The latter case also had a deletion of chromosome 9, del(9)(q12q22) as an additional abnormality. Reverse transcriptase-polymerase chain reaction study revealed no AML1/ETO fusion transcript in case 2. Dual-color fluorescence in situ hybridization (FISH) assay using two probes (BAC92 and YAC412A4) convincingly demonstrated that the chromosomal material from 8q was translocated onto 19q rather than 19p in case 2. Thus, we consider t(8;19)(q22;q13) a true "simple" variant of t(8;21), and assume that a fusion gene resulting from the t(8;19) may contain the ETO gene located at 8q22 and an unknown partner gene from 19q13, which probably is a new transcription factor, whose molecular entity warrants further study.

Isolation and identification of metabolites of porfiromycin formed in the presence of a rat liver preparation

The isolation and identification of the major metabolites of porfiromycin formed in the presence of a rat liver preparation under aerobic conditions were performed with high-performance liquid chromatography and electrospray ionization mass spectrometry. Porfiromycin was extensively metabolized by the rat liver preparation in an aqueous 0.1 M potassium phosphate buffer (pH 7.4) containing an NADPH generating system at 37 degrees C. A total of eight metabolites was identified as mitosene analogs. Of these, three primary metabolites are 2-methylamino-7-aminomitosene, 1,2-cis and 1,2-trans-1-hydroxy-2-methylamino-7-aminomitosene, which are consistent with those previously observed in hypoxia using purified rat liver NADPH-cytochrome c reductase. Interestingly, 2-methylamino-7-aminomitosene is a reactive metabolite, which undergoes further activation at the C-10 position by the loss of carbamic acid and then links with the 7-amino group of the primary metabolites to yield two dimeric adducts. In addition, three phosphate adducts, 10-decarbamoyl-2-methylamino-7-aminomitosene-10-phosphate, 1,2-cis and 1,2-trans-2-methylamino-7-aminomitosene-1-phosphate, were also identified in the incubation system. The configurations of the diastereoisomeric metabolites were determined with (1)HNMR and phosphatase digestion. On the basis of the metabolite profile, we propose in vitro metabolic pathways for porfiromycin. The findings provide direct evidence for understanding the reactive nature and hepatic metabolism of the drug currently in phase III clinical trials.

Studies on treatment of acute promyelocytic leukemia with arsenic trioxide: remission induction, follow-up, and molecular monitoring in 11 newly diagnosed and 47 relapsed acute promyelocytic leukemia patients

Fifty-eight acute promyelocytic leukemia (APL) patients (11 newly diagnosed and 47 relapsed) were studied for arsenic trioxide (As2O3) treatment. Clinical complete remission (CR) was obtained in 8 of 11 (72.7%) newly diagnosed cases. However, As2O3 treatment resulted in hepatic toxicity in 7 cases including 2 deaths, in contrast to the mild liver dysfunction in one third of the relapsed patients. Forty of forty-seven (85.1%) relapsed patients achieved CR. Two of three nonresponders showed clonal evolution at relapse, with disappearance of t(15;17) and PML-RARalpha fusion gene in 1 and shift to a dominant AML-1-ETO population in another, suggesting a correlation between PML-RARalpha expression and therapeutic response. In a follow-up of 33 relapsed cases over 7 to 48 months, the estimated disease-free survival (DFS) rates for 1 and 2 years were 63.6% and 41.6%, respectively, and the actual median DFS was 17 months. Patients with white blood cell (WBC) count below 10 x 10(9)/L at relapse had better survival than those with WBC count over 10 x 10(9)/L (P =.038). The duration of As2O3-induced CR was related to postremission therapy, because there was only 2 of 11 relapses in patients treated with As2O3 combined with chemotherapy, compared with 12 of 18 relapses with As2O3 alone (P =.01). Reverse transcription polymerase chain reaction (RT-PCR) analysis in both newly diagnosed and relapsed groups showed long-term use of As2O3 could lead to a molecular remission in some patients. We thus recommend that ATRA be used as first choice for remission induction in newly diagnosed APL cases, whereas As2O3 can be either used as a rescue for relapsed cases or included into multidrug consolidation/maintenance clinical trials.

[Complications of PPP: prevention and management strategies]

OBJECTIVE

In order to minimize the complications of palatopharyngoplasty (PPP).

METHOD

Perioperative complications of PPP of 110 cases were analysed.

RESULT

In our series, the complications included velopharyngeal insufficiency (28 cases), hypertensive crisis (12 cases), respiratory embarrassment (12 cases), wound dehiscence (2 cases), local hemorrhage (1 cases), hypovolemic shock (1 cases) and nasopharyngeal stricture (1 cases).

CONCLUSION

It is concluded that prevention is important. Prevention strategies included: 1. Preoperative careful examination; 2. Using local anesthesia; 3. Intraoperative monitor ECG, blood pressure and oxygen saturation; 4. Intraoperative inbreathing oxygen; 5. Staunch blood thoroughly; 6. Postoperative proper treatment with steroid; 7. CPAP treatment should be applied before PPP in the severe OSAS.

[Study of TEL-AML1 fusion gene in childhood B-lineage acute lymphoblastic leukemia]

OBJECTIVE

To determine the incidence of TEL-AML1 fusion gene and its role in clinical diagnosis and prognosis of childhood B-lineage acute lymphoblastic leukemia (B-ALL), and to compare the two techniques: nested RT-PCR and dual-color fluorescence in situ hybridization (FISH).

METHODS

Nested RT-PCR and dual-color FISH techniques were used to detect TEL-AML1 fusion gene.

RESULTS AND CONCLUSION

TEL-AML1 fusion transcript was found in 22.5%(9/40) of patients with B-ALL by RT-PCR. The prognosis of these TEL-AML1 positive patients was relatively good and the complete remission rate was 100%. Both RT-PCR and FISH techniques were proved to be useful for detecting TEL-AML1 fusion gene and suitable for clinical diagnosis and prognosis evaluation.

Chromosomal aberrations during progression of chronic myeloid leukemia identified by cytogenetic and molecular cytogenetic tools: implication of 1q12-21

To study the genomic abnormality underlying the acute transformation of chronic myeloid leukemia (CML), 15 CML patients in blast crisis (BC), 3 in accelerated phase (AP), and 20 in chronic phase (CP) were analyzed by conventional cytogenetics, comparative genomic hybridization (CGH), and dual-color chromosomal painting. Philadelphia (Ph) chromosome was identified in every case studied. Only 5 among 20 CP patients had additional abnormalities while 13 of 18 patients with disease progression (BC + AP) showed extra numerical and/or structural chromosomal aberrations. Cytogenetically, the most common chromosome gains during BC and AP were double or triple Ph chromosomes (5 of 14 cases) and trisomy 8 (5 of 14 cases). Trisomies 7 and 17 (1 of 14 cases each) were also observed. CGH analysis detected genetic imbalances in eight cases. Gains of chromosome 20 (3 cases) and 17q (2 cases) were observed, respectively. The recurrent chromosome loss was the deletion of the short arm of chromosome 17, seen in one case with i(17)(q10) and one case with an unbalanced translocation (1;17). In one case, a very complex chromosomal rearrangement, del(3),del(6),der(6)t(17;3;6),der(17)t(6;17), was seen. A novel finding of this work is the involvement of chromosome 1(q12-21qter) in CML disease progression. Overrepresentation of 1(q12-21qter) region was detected by CGH in one case which had a derivative chromosome 17. This abnormal chromosome was later confirmed by fluorescence in situ hybridization (FISH) painting to be a fusion between chromosome 1 and 17 to form the der(17)t(1;17) (q12-21;p11). Two other cases showed the same region being involved in translocations, t(1;10)(q12-21;q26) and t(1;11)(q12-21;p15). It is possible that one or more genes residing on chromosome 1q12-21 may be important in the acute transformation of CML. In conclusion, we find that the combined use of CGH, chromosome painting, and classic cytogenetic analysis allows a better evaluation of the genomic aberration involved in CML blastic transformation, and offers new directions for its further molecular investigations.

[Studies on complex chromosomal translocation and their relevance to clinical prognosis in acute promyelocytic leukemia]

OBJECTIVE

To study the relationship between the complex chromosome translocation in acute promyelocytic leukemia(APL, M3) and clinical therapy and prognosis.

METHODS

Chromosome translocation and PML-RAR fusion transcript in three APL patients were studied by using karyotypic analysis, fluorescence in situ hybridization and reverse transcriptase/polymerase chain reaction.

RESULTS

The findings revealed that all these cases had PML/RAR A gene rearrangement. Apart from the chromosomes 15 and 17 involved in the translocation, other multiple chromosomes including 5, 11, 16, 22 were also implicated in complex translocations, which to some extent seemed to be related with clinical prognosis.

CONCLUSION

This study provides additional information for monitoring clinical therapy and prognostic evaluation.

Detection of chromosome over- and underrepresentations in hyperdiploid acute lymphoblastic leukemia by comparative genomic hybridization

Chromosomal analysis of acute lymphoblastic leukemia (ALL) is often difficult because of the suboptimal in vitro growth of the immature lymphoid cell and the poor morphology obtained. In this study, we describe the application of comparative genomic hybridization (CGH) to investigate the genomic abnormalities in 14 patients with ALL, all of whom had cytogenetically identified numerical aberrations or gross chromosomal structural alteration. With the use of CGH, regional or whole chromosome overrepresentation or both were found to be more frequent than underrepresentation (52 gains vs. 6 losses), the most common gains being chromosomes 21 and X. The results of the comparison between CGH and conventional R-banding analysis could be classified into three categories: (1) in three cases, including two with trisomy, CGH and banding analysis gave identical results; (2) in six cases with hyperdiploidy and two cases presenting chromosome structural abnormalities, the results were consistent but with minor discrepancies; (3) in three cases, including two with triploidy and tetraploidy and one with chimeric karyotype together with +22, the data from CGH and cytogenetical analysis were discrepant. CGH could not find the triploidy and tetraploidy. Our results suggest that CGH has certain value in the detection of gains or losses of chromosome materials in hyperdiploid ALL. Nevertheless, the combination of CGH and conventional karyotyping provides more precise information on the genomic imbalance in ALL.

[Detection of bcr gene rearrangement in chronic myeloid leukemia by fluorescence in situ hybridization]

OBJECTIVE

To detect bcr gene rearrangement in chronic myeloid leukemia (CML).

METHODS

Bcr rearrangement was detected by fluorescence in situ hybridization (FISH), using 765E3, a yeast artificial chromosome (YAC)-derived probe flanking the breakpoint within bcr gene.

RESULTS

Nine patients with CML were examined, bcr gene rearrangement was revealed in 5 cases in chronic phase, 2 in blastic phase, and one after interferon-alpha therapy. The karyotype of 1 case after autologous bone marrow transplantation (ABMT) was chimera with normal and bcr gene rearrangement chromosomes.

CONCLUSION

YAC765E3 is a useful probe for detecting bcr gene rearrangement. FISH technique is likely an important tool for monitoring of treatment and revealing minimal residual disease in CML.

Use of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL): I. As2O3 exerts dose-dependent dual effects on APL cells

Recent clinical studies in China showed that As2O3 is an effective and relatively safe drug in the treatment of acute promyelocytic leukemia (APL). We found previously that As2O3 can trigger apoptosis of APL cell line NB4 cells, which is associated with downregulation of bcl-2 gene expression and modulation of PML-RAR alpha chimeric protein. To further understand the mechanisms of this alternative therapy for APL, we investigated in this report the effects of a wide range of concentrations of As2O2 on cultured primary APL cells, all-trans retinoic acid (ATRA)-susceptible (NB4 cells) and ATRA-resistant (MR2 subclone) APL cell lines. The results indicated that As2O3 had dose-dependent dual effects on APL cells: inducing preferentially apoptosis at relatively high concentrations (0.5 to 2 micromol/L) and inducing partial differentiation at low concentrations (0.1 to 0.5 micromol/L). The rapid modulation and degradation of PML-RAR alpha proteins, which was induced by As2O3 at 0.1 to 2 micromol/L, could contribute to these two effects. Bone marrow and peripheral blood examination showed that myelocyte-like cells, probably as a result of partial in vivo differentiation, and degenerative cells increased after 2 to 3 weeks of continuous in vivo As2O3 treatment when leukemic promyelocytes decreased. In conclusion, combination of induction of apoptosis and partial differention could be the main cellular mechanisms of As2O3 in the treatment of APL, and PML-RAR alpha could play an important role in determining the specific effects of As2O3 on APL cells.