[Curative effect of percutaneous microwave ablation therapy on hepatocellular carcinoma survival: a 15-year real-world study]

Objective: To evaluate the long-term efficacy of percutaneous microwave ablation (MWA) therapy for hepatocellular carcinoma. Methods: 2054 cases with Barcelona Clinic Liver Cancer (BCLC) stage 0~B at the Fifth Medical Center of the Chinese People's Liberation Army General Hospital from January 2006 to September 2020 were retrospectively collected. All patients were followed up for at least 2 years. The primary endpoint of overall survival and secondary endpoints (tumor-related survival, disease-free survival, and postoperative complications) of patients treated with ultrasound-guided percutaneous MWA were analyzed. Kaplan-Meier method was used for stratified survival rate analysis. Fine-and-Gray competing risk model was used to analyze overall survival. Results: A total of 5 503 HCC nodules [mean tumor diameter (2.6±1.6) cm] underwent 3 908 MWAs between January 2006 and September 2020, with a median follow-up time of 45.6 (24.0 -79.2) months.The technical effectiveness rate of 5 375 tumor nodules was 97.5%. The overall survival rates at 5, 10, and 15-years were 61.6%, 38.8%, and 27.0%, respectively. The tumor-specific survival rates were 67.1%, 47.2%, and 37.7%, respectively. The free tumor survival rates were 25.8%, 15.7%, and 9.9%, respectively. The incidence rate of severe complications was 2.8% (108/3 908). Further analysis showed that the technical effectiveness and survival rate over the passing three time periods from January 2006-2010, 2011-2015, and 2016-September 2020 were significantly increased, with P < 0.001, especially for liver cancer 3.1~5.0 cm (P < 0.001). Conclusion: Microwave ablation therapy is a safe and effective method for BCLC stage 0-B, with significantly enhanced technical efficacy and survival rate over time.

Advancing Glucose Conjugated Gibberellins Discovery: A Structure-Oriented Screening and Identification Method for Unraveling Gibberellin Metabolites in Plants

Gibberellins (GAs) play a pivotal role in modulating plant growth and development. Glucose-conjugated gibberellins (Glc-GAs), a prevalent conjugated form of GAs, regulate intracellular GA levels by the coupling and decoupling of glucose groups. However, the diversity of Glc-GAs identified within individual species remains limited, hinting at a multitude of yet undiscovered gibberellin metabolites. This lacuna poses considerable impediments to research efforts dedicated to comprehensively delineating the GA metabolic pathway. In this study, we developed a structure-oriented screening and identification method for Glc-GAs in plant species by employing LC-MS/MS coupled with chemical derivatization. Through the application of chemical derivatization technique, carboxyl groups on Glc-GAs were labeled which effectively enhanced the sensitivity and selectivity of mass spectrometry detection for these compounds. Concurrently, the integration of mass spectrometry fragmentation and chromatographic retention behavior facilitated the efficient screening and identification of potential Glc-GAs. With this strategy, we screened and identified 12 potential Glc-GAs from six plant species. These findings expand the Glc-GA diversity in plants and contribute to understanding GA metabolic pathways.

The feedback regulation of carbohydrates intake on food intake and appetite in grass carp (Ctenopharyngodon idella)

Improving carbohydrate utilization can contribute to sustainability of aquaculture. In order to explore the feedback mechanism of glucose homeostasis in fish, one control diet (25% carbohydrate and 40% protein), one relatively high carbohydrate diet named HG (42% carbohydrate and 40% protein), and one high dietary carbohydrate coupled with relatively low protein diet named HGP (42% carbohydrate and 25% protein) were fed to grass carp for 40 days. After the feeding trial, HG group impeded the food intake and growth performance of fish compared with the other two groups. Meanwhile, the serum glucose and insulin level were both significantly elevated under the condition of high carbohydrates intake when compared HG with control group. However, although no significant difference was observed in peripheral glucose or insulin between HG and HGP groups, fish fed with HGP diet increased growth performance and food intake compared with the HG group. Gene expression data indicated that fish selectively regulated the expressions of the cerebral anorexigenic genes (cart and pomc) to adapt to the HG and HGP intake. Therefore, the HGP diet with high carbohydrate and low protein was more suitable for grass carp feeding and growth when compared with the other two diets, possibly because the diet composition was closer to the natural food of this fish. In addition, the serum leptin level was highly consistent with changes in food intake and anorexigenic gene expressions when comparing the three experimental diets, indicating that leptin might be the key to mediate the feedback regulation of carbohydrates intake on food intake and appetite in fish.

A structure-guided screening strategy for the discovery and identification of potential gibberellins from plant samples using liquid chromatography-mass spectrometry assisted by chemical isotope labeling

Gibberellins (GAs) play crucial roles in plant growth and development, and their regulatory functions rely on complex metabolic networks and signaling pathways. Therefore, the exploration of GAs metabolic network is of great importance. However, limited GAs have been found in given plant species, which makes it difficult to comprehensively study the GAs metabolic network. Herein, a structure-guided strategy for GAs screening based on liquid chromatography-mass spectrometry analysis assisted by chemical isotope labeling (CIL-LC-MS) was developed. In the proposed strategy, N,N-dimethyl ethylenediamine (DMED) and its isotopologue d₄-DMED were used to label GAs. In light of the characteristic fragmentation patterns exhibited by the labeled GAs, four principles were summarized to screen the potential GAs from plant tissues. Subsequently, the MS/MS fragmentation behavior and quantitative structure-retention relationship (QSRR) model were employed to assist in deciphering structures of GA candidates. With this strategy, thirty potential GAs were screened out and identified from five plant species. Seven of them were confirmed by the authentic standards. Twenty-two of them have not been reported before in the five plant species used in this study, including thirteen that have been reported in other plant species and nine that have never been reported in any plant species. Noteworthily, a total of nine potential GAs were speculated to be novel 16, 17-double hydrated GAs, which indicated that the 16, 17-double hydration may be a ubiquitous metabolic pathway of GAs in plants. This study was the first attempt to establish a structure-guided screening strategy for GAs. Our findings have enriched the GA species in plants and expanded the GAs family, which may be helpful for study of the metabolic pathway and physiological function of GAs.

Rapid Analysis of Monosaccharides in Sub-milligram Plant Samples Using Liquid Chromatography-Mass Spectrometry Assisted by Post-column Derivatization

Monosaccharides play important roles in plant growth and development, and their biofunctions are closely related to their endogenous contents. Therefore, the determination of monosaccharides is beneficial for the further study of monosaccharide biofunction. In this work, we developed a liquid chromatography-mass spectrometry analytical method assisted by a post-column derivatization technique (LC-PCD-MS) for the fast and automatic determination of 16 monosaccharides in samples. Post-column chemical derivatization of monosaccharides was performed by a reaction of monosaccharides with 4-benzylaminobenzeneboronic acid (4-PAMBA) through boronate ester formation in a three-way connector. 4-PAMBA worked as a derivatization reagent to improve the selectivity and sensitivity of monosaccharide detection by MS. The developed LC-PCD-MS method integrates LC separation, chemical derivatization, and MS detection in one run, thus greatly reducing the analysis time for each sample. The limits of detection and limits of quantification for 16 monosaccharides were in the range of 0.002-0.1 and 0.007-0.5 ng/mL, respectively. Good linearity was obtained from the linear regression, with a determination coefficient (R²) ranging from 0.9928 to 1.0000. The relative recoveries were in the range of 80.7-117.8%, with the intra- and interday relative standard deviations less than 19.7 and 16.5%, respectively, indicating good accuracy and acceptable reproducibility of the method. Finally, the method was successfully applied to investigate the spatial and temporal distribution of 16 monosaccharides in the developing flower and germinating seed of Arabidopsis thaliana.

Two SLENDER AND CRINKLY LEAF dioxygenases play an essential role in rice shoot development

It is clear that 2-oxoglutarate-dependent dioxygenases have critical functions in salicylic acid (SA) metabolism in plants, yet their role in SA biosynthesis is poorly understood. Here, we report that two dioxygenase-encoding genes, SLENDER AND CRINKLY LEAF1 (SLC1) and SLC2, play essential roles in shoot development and SA production in rice. Overexpression of SLC1 (SLC1-OE) or SLC2 (SLC2-OE) in rice produced infertile plants with slender and crinkly leaves. Disruption of SLC1 or SLC2 led to dwarf plants, while simultaneous down-regulation of SLC1 and SLC2 resulted in a severe defect in early leaf development. Enhanced SA levels in SLC1-OE plants and decreased SA levels in slc1 and slc2 mutants were observed. Accordingly, these lines all showed altered expression of a set of SA-related genes. We demonstrated that SLC1 interacts with homeobox1 (OSH1), and that either the knotted1-like homeobox (KNOX1) or glutamate, leucine, and lysine (ELK) domain of OSH1 is sufficient for accomplishing this interaction. Collectively, our data reveal the importance of SLC1 and SLC2 in rice shoot development.

Expansion of sweet taste receptor genes in grass carp (Ctenopharyngodon idellus) coincided with vegetarian adaptation

BACKGROUND

Taste is fundamental to diet selection in vertebrates. Genetic basis of sweet taste receptor in the shaping of food habits has been extensively studied in mammals and birds, but scarcely studied in fishes. Grass carp is an excellent model for studying vegetarian adaptation, as it exhibits food habit transition from carnivory to herbivory.

RESULTS

We identified six sweet taste receptors (gcT1R2A-F) in grass carp. The four gcT1R2s (gcT1R2C-F) have been suggested to be evolved from and paralogous to the two original gcT1R2s (gcT1R2A and gcT1R2B). All gcT1R2s were expressed in taste organs and mediated glucose-, fructose- or arginine-induced intracellular calcium signaling, revealing they were functional. In addition, grass carp was performed to prefer fructose to glucose under a behavioral experiment. Parallelly, compared with gcT1R2A-F/gcT1R3 co-transfected cells, gcT1R2C-F/gcT1R3 co-transfected cells showed a higher response to plant-specific fructose. Moreover, food habit transition from carnivory to herbivory in grass carp was accompanied by increased gene expression of certain gcT1R2s.

CONCLUSIONS

We suggested that the gene expansion of T1R2s in grass carp was an adaptive strategy to accommodate the change in food environment. Moreover, the selected gene expression of gcT1R2s might drive the food habit transition from carnivory to herbivory in grass carp. This study provided some evolutional and physiological clues for the formation of herbivory in grass carp.

Differential Roles of Two Leptin Gene Paralogues on Food Intake and Hepatic Metabolism Regulation in Mandarin Fish

Leptin affects food intake regulation and energy homeostasis in mammals, as opposed to mammals who have a single leptin gene, fish have duplicated leptin gene paralogues. Until now, most functional studies on fish focused on the first reported paralogue without much explanation on specific gene paralogue. This study successfully expressed two homologous recombinant mandarin fish leptin genes (LepA and LepB) for the first time. To explore the differential roles of these two gene paralogues involved in food intake and energy homeostasis, mandarin fish were treated with homologous recombinant LepA and LepB proteins by acute IP administration. The results showed that LepB inhibited the food intake of mandarin fish after acute IP administration through modifying the expressions of hypothalamic orexigenic genes, while LepA had no significant effect on its food intake. In addition, LepB administration decreased the hepatic glycogen level through regulating the gene expressions of glycogen synthase and glycogen phosphorylase in mandarin fish until 4 d, while LepA did not change the hepatic glycogen level as it failed to change the expressions of these regulatory genes. Moreover, LepA and LepB downregulated the expressions of key gluconeogenic genes (phosphofructokinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase), indicating both mandarin fish leptins could regulate the rate of glucose production. However, these two gene paralogues presented secondary effects on lipid metabolism as they only enhanced the triglyceride level by modifying the gene expressions of adipose triglyceride lipase or acetyl CoA carboxylase just for 1 d after IP. Therefore, LepB played an important role in food intake and glucose homeostasis regulation, while LepA showed a limited role in gluconeogenesis and lipid metabolism.

Performance enhancement of oxygen evolution reaction through incorporating bimetallic electrocatalysts in two-dimensional metal–organic frameworks

We designed and synthesized a series of bimetallic and monometallic 2D metal–organic framework electrocatalysts with excellent stability, discussing their different electrochemical catalysts for oxygen evolution reaction (OER).

Changes of DNA Methylation Pattern in Metabolic Pathways Induced by High-Carbohydrate Diet Contribute to Hyperglycemia and Fat Deposition in Grass Carp (Ctenopharyngodon idellus)

Although studies have determined that epigenetics plays an essential role in regulating metabolism in mammals, research on nutrition-related DNA methylation remains to be lacking in teleosts. In the present study, we provided a hepatic whole-genome DNA methylation analysis in grass carp fed with moderate- or excessive-carbohydrate-level diet. Although a high-carbohydrate (HC) diet significantly changed the mRNA expression levels of metabolic genes, it did not affect the global genomic DNA methylation levels in grass carp liver. However, compared with the control group, 3,972 genes were hyper-methylated and 2,904 genes were hypo-methylated in the promoter region. Meanwhile, 10,711 genes were hyper-methylated and 6,764 genes were hypo-methylated in the gene body region in the HC group. These differentially methylated genes (DMGs) were enriched in multiple pathways, including carbohydrate metabolism, insulin pathway, lipid metabolism, and adipocytokine signaling pathway. In addition, the variations in DNA methylation significantly regulated the transcription levels of key genes of metabolism, which could affect the glucose concentrations and the lipid deposition of grass carp. Furthermore, we compared the DNA methylation alterations of genes in glucose metabolism and obesity pathways of grass carp with those of mammalian models in different nutritional states. The results showed that most of the DMGs in grass carp were also regulated by DNA methylation in mammals when the nutritional state changed. The findings revealed more differentially methylated regions and candidate genes for glucose metabolism and broken species boundaries.

Stable isotope labeling combined with liquid chromatography-tandem mass spectrometry for comprehensive analysis of short-chain fatty acids

Short-chain fatty acids (SCFAs) are one class of bacterial metabolites mainly formed by gut microbiota from undigested fibers and proteins. These molecules are able to mediate signal conduction processes of cells, acting as G protein-coupled receptors (GPR) activators and histone deacetylases (HDAC) inhibitors. It was reported that SCFAs were closely associated with various human diseases. However, it is still challenging to analyze SCFAs because of their diverse structures and broad range of concentrations. In this study, we developed a highly sensitive method for simultaneous detection of 34 SCFAs by stable isotope labeling coupled with ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS/MS) analysis. In this respect, a pair of isotope labeling reagents, N-(4-(aminomethyl)benzyl)aniline (4-AMBA) and N-(4-(aminomethyl)benzyl)aniline-d₅ (4-AMBA-d₅), were synthesized to label SCFAs from the feces of mice and SCFA standards, respectively. The 4-AMBA-d₅ labeled SCFAs were used as internal standards to compensate the ionization variances resulting from matrix effect and thus minimize quantitation deviation in MS detection. After 4-AMBA labeling, the retention of SCFAs on the reversed-phase column increased and the separation resolution of isomers were improved. In addition, the MS responses of most SCFAs were enhanced by up to three orders of magnitude compared to unlabeled SCFAs. The limits of detection (LODs) of SCFAs were as low as 0.005 ng/mL. Moreover, good linearity for 34 SCFAs was obtained with the coefficient of determination (R²) ranging from 0.9846 to 0.9999 and the intra- and inter-day relative standard deviations (RSDs) were <17.8% and 15.4%, respectively, indicating the acceptable reproducibility of the developed method. Using the developed method, we successfully quantified 21 SCFAs from the feces of mice. Partial least squares discriminant analysis (PLS-DA) and t-test analysis showed that the contents of 9 SCFAs were significantly different between Alzheimer's disease (AD) and wide type (WT) mice fecal samples. Compared to WT mice, the contents of propionic acid, isobutyric acid, 3-hydroxybutyric acid, and 3-hydroxyisocaleric acid were decreased in AD mice, while lactic acid, 2-hydroxybutyric acid, 2-hydroxyisobutyric acid, levulinic acid, and valpronic acid were increased in AD mice. These significantly changed SCFAs in the feces of AD mice may afford to a better understanding of the pathogenesis of AD. Taken together, the developed UHPLC-ESI-MS/MS method could be applied for the sensitive and comprehensive determination of SCFAs from complex biological samples.

A new boronic acid reagent for the simultaneous determination of C27-, C28-, and C29-brassinosteroids in plant tissues by chemical labeling-assisted liquid chromatography-mass spectrometry

Brassinosteroids (BRs) are endogenous plant growth-promoting hormones affecting growth and development during the entire life cycle of plants. Naturally occurring BRs can be classified into C₂₇-, C₂₈-, or C₂₉-BRs based on the nature of the alkyl groups occupying the C-24 position in the side chain of the 5a-cholestane carbon skeleton. However, while C₂₇-BRs exhibit similar bioactivities to C₂₈- and C₂₉-BRs, the biosynthetic pathways of C₂₇-BRs in plants have not yet been clearly characterized. In addition to a lack of biochemical and enzymatic evidence regarding the biosynthetic pathways of C₂₇-BRs, even most of the intermediate compounds on their pathways have not been explored and identified due to the lower endogenous levels of C₂₇-BRs. Therefore, the development of highly sensitive analytical methods is essential for studying the biosynthetic pathways and physiological functions of C₂₇-BRs. Accordingly, this study establishes qualitative and quantitative methods for identifying and detecting C₂₇-, C₂₈-, and C₂₉-BRs using a newly synthesized boronic acid reagent denoted as 2-methyl-4-phenylaminomethylphenylboronic acid (2-methyl-4-PAMBA) in conjunction with liquid chromatography-mass spectrometry (LC-MS). Labeling with 2-methyl-4-PAMBA provides derivatives with excellent stability, and the detection sensitivities of BRs, particularly for C₂₇-BRs, are dramatically improved. The limits of detection (with a signal-to-noise ratio of 3) for six BRs, including 2 C₂₇-BRs (28-norCS and 28-norBL), 3 C₂₈-BRs (CS, BL, and TY), and a single C₂₉-BR (28-homoBL), are found to be 0.10-1.68 pg/mL after labeling with 2-methyl-4-PAMBA. Finally, the proposed analytical method is successfully applied for the detection of endogenous BRs in small mass samples of Oryza sativa seedlings, Rape flowers, Arabidopsis shoots, and Arabidopsis flowers. In addition, a method for profiling potential BRs in plants is also developed using LC-MS in multiple reaction monitoring scan mode assisted by 2-methyl-4-PAMBA and 2-methyl-4-PAMBA-d₅ labeling. The developed method is able to identify 10 potential BRs in a Rape flower extract. The proposed quantitative and qualitative methods established by 2-methyl-4-PAMBA labeling are helpful for facilitating an understanding of the physiological functions and biosynthetic pathways of BRs, particularly for C₂₇-BRs. Graphical abstract.

Metabolic analysis of the melatonin biosynthesis pathway using chemical labeling coupled with liquid chromatography-mass spectrometry

Characterization of the melatonin (MLT) biosynthesis pathway in plants is still limited. Additionally, a metabolomic analysis of MLT biosynthesis in plants is still a challenge due to analyte structural and chemical diversity, low analyte abundances, and plant matrix complexities. Herein, a sensitive liquid chromatography-mass spectrometry (LC-MS) method enabling the simultaneous determination of seven plant MLT biosynthetic metabolites was developed. In the proposed strategy, the targeted metabolites, which included tryptophan (Trp), tryptamine (TAM), 5-hydroxytryptophan (5HTP), serotonin (5HT), N-acetylserotonin (NAS), 5-methoxytryptamine (5MT), and MLT, were purified from plant extracts using a one-step dispersive solid-phase extraction (DSPE). The samples were then chemically labeled with dansyl chloride (DNS-Cl), followed by analysis using LC-MS. The limit of detection (LOD) values ranged from 0.03 to 1.36 pg/mL and presented a 22- to 469-fold decrease when compared to the unlabeled metabolites. Due to the high sensitivity of the proposed method, the consumption of plant materials was reduced to 10 mg FW. Ultimately, the established method was utilized to examine the distributions of MLT and its intermediates in rice shoots and roots with or without cadmium (Cd) stress. The results suggested that under normal condition, MLT may also be generated via a Trp/TAM/5HT/5MT/MLT path (Pathway II) in addition to the previously reported Trp/TAM/5HT/NAS/MLT path (Pathway I), although Pathway I was shown to be dominant. During Cd stress, MLT was also shown to be produced through these two pathways, with Pathway II shown to be dominant in rice shoots and roots.

Macular integrity assessment to determine the association between macular microstructure and functional parameters in diabetic macular edema

AIM

To respectively evaluate macular morphological features and functional parameters by using spectral-domain optical coherence tomography (SD-OCT) and macular integrity assessment (MAIA) in patients with diabetic macular edema (DME).

METHODS

This prospective, non-controlled, open study included 61 eyes of 38 consecutive patients with DME. All patients underwent best-corrected visual acuity (BCVA) measurement, MAIA microperimetry, and SD-OCT. DME morphology, including central retinal thickness (CRT) and central retinal volume (CRV); integrity of the external limiting membrane (ELM) and photoreceptor inner segment/outer segment (IS/OS) junction; and the deposition of hard macular exudates were assessed within a 1000-µm central subfield area. MAIA microperimetry parameters evaluated were average threshold (AT)-retinal sensitivity, macular integrity index (MI), fixation points within a circle of radius 1° (P1) and 2° (P2), and bivariate contour ellipse area considering 63% and 95% of the fixation points (A63 and A95, respectively).

RESULTS

MI was significantly higher in eyes with disrupted ELM or IS/OS, compared with eyes with intact ELM and IS/OS. Values of BCVA (logMAR), total AT, AT within 1000-µm diameter, P2, A63, A95, and CRT were significantly worse in eyes with disrupted IS/OS, compared with eyes with intact IS/OS. The values of BCVA (logMAR), AT within 1000-µm diameter, and CRT were significantly worse in eyes with disrupted ELM, compared with eyes with intact ELM. These parameters were not significantly different between eyes with or without hard macular exudate deposition. CRV was not significantly different in the presence or absence of the integrity of ELM, IS/OS, or deposition of hard macular exudates. At the center, nasal and temporal sectors of the fovea, significant negative correlations were observed between retinal thickness and AT of the corresponding area. At the inferior and superior sectors of the fovea, no correlations were observed between retinal thickness and AT of the corresponding area. In the intact IS/OS group, significant negative correlations were observed between CRT and central AT. There was no correlation between retinal sensitivity and thickness when the IS/OS layer was disrupted. Multiple linear regression analyses revealed that IS/OS integrity was an independent factor affecting MI.

CONCLUSION

Functional (BCVA and visual field) and morphological parameters (retinal thickness) were significantly associated with an intact IS/OS. Local photoreceptor integrity was a strong predictor of local visual function throughout the retina. MI revealed the functional status in DME, reflecting the IS/OS juction status in the macula.

Spatio-temporal profiling of abscisic acid, indoleacetic acid and jasmonic acid in single rice seed during seed germination

Abscisic acid (ABA), indoleacetic acid (IAA) and jasmonic acid (JA) are plant hormones that were reported to play indispensable roles during seed germination. However, the interactions between these plant hormones during rice seed germination have still not been explored clearly. A sensitive method for determination of these plant hormones would be beneficial for the exploration of such interactions. Herein, we present a liquid chromatography coupled with mass spectrometry (LC-MS) method for the quantification of ABA, IAA and JA in a single tissue of rice seed to investigate the spatio-temporal distribution of these plant hormones during rice seed germination. To this end, an in silico strategy was developed in order to select a derivatization reagent with an ideal sensitivity of MS detection. This strategy was confirmed with experimental studies on three reagents N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC), N,N-dimethylethylenediamine (DMED), and N-(acridin-9-yl)-2-bromoacetamide (AYBA) and their formic acid derivatives. Our results from the in silico and LC-MS experiments show that AYBA is a good derivatization reagent for ABA, IAA and JA due to its reasonable ionization efficiency in electrospray ionization mass spectrometry (ESI-MS) and excellent hydrophobicity. Finally, a sensitive LC-MS method upon AYBA was established for the determination of ABA, IAA and JA in germinated seeds. Good linearities for ABA, IAA, and JA were obtained with correlation coefficients greater than 0.99. The limits of detection (LODs) were in the range of 0.14-0.16 pg mL^-1. The method exhibits good precisions with RSD 1.5%-13.8% (intra-day) and 1.2%-7.3% (inter-day) and acceptable recoveries (88.6%-102.9%, n = 6). Finally, the method was successfully employed in the spatio-temporal profiling of ABA, IAA and JA in a single tissue of rice seed during rice seed germination.

Two isostructural Ln-MOFs showing luminescent sensing (Eu) and slow magnetic relaxation (Dy) properties

Two isostructural lanthanide-based MOFs are reported. The Eu-MOF exhibiting luminescence properties can be utilized in ion detection and the Dy-MOF displays SMM behavior with an energy barrier (ΔU_eff) of 54 K.

Profiling of potential brassinosteroids in different tissues of rape flower by stable isotope labeling - liquid chromatography/mass spectrometry analysis

Brassinosteroids (BRs) play crucial roles in a variety of physiological processes in plants. The full elucidation of the functions of RBs relies on sensitive detection and accurate measurement of BRs in plants. However, the identification and quantification of BRs are challenging due to their low abundance as well as poor ionization efficiencies during mass spectrometry-based analysis. Herein, we developed a highly sensitive and selective strategy for profiling potential BRs in plants by stable isotope labeling liquid chromatography multiple reaction monitoring scan mass spectrometry (SIL-LC-MRM-MS) analysis. In the strategy, we used a pair of stable isotope labeling reagents 4-phenylaminomethyl-benzeneboronic acid (4-PAMBA) and d₅-4-phenylaminomethyl-benzeneboronic acid (4-PAMBA-d₅) that can react with C22-C23 cis-diol on BRs for profiling potential BRs in plant tissues. The 4-PAMBA and 4-PAMBA-d₅ labeled BRs could generate two characteristic neutral loss under collision induced dissociation (CID), respectively, which is used to establish the MRM-based detection and screening. The precursor ions of BRs labeled with 4-PAMBA and 4-PAMBA-d₅ were set according to the reported structures of BRs, and the corresponding product ions were predicted by subtracting the lost neutral loss. In this respect, corresponding precursor ions and product ions in MRM transitions are formed. The peak pairs with a fixed mass difference, similar retention times and intensities were assigned as potential BRs. Using the developed SIL-LC-MRM-MS strategy, we successfully found 13 potential BR in different tissues of rape flower. Taken together, the SIL-LC-MRM-MS analytical strategy is promising for profiling potential BRs as well as other compounds that have the same functional moiety from complex biological samples.

Comprehensive Profiling of Phytohormones in Honey by Sequential Liquid-Liquid Extraction Coupled with Liquid Chromatography-Mass Spectrometry

Honey exhibits various nutritional and medicinal functions, which are highly related to the active components; thus, the exploration of new compounds in honey is of great importance. Because honey is a byproduct of flower nectar, which is rich in phytohormones, the existence of phytohormones in honey is anticipated. In this research, a method for comprehensive profiling of 49 phytohormones in honey was developed by sequential liquid-liquid extraction (LLE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Good linearities for 49 phytohormones were obtained with correlation coefficients (R) larger than 0.9913. The limits of detection (LODs) were in the range of 0.2-628.2 pg/mL. Satisfied reproducibility and reliability were achieved by evaluation of the intra- and interday precisions with relative standard deviations (RSDs) less than 15.8% and relative recoveries ranging from 80.4 to 123.7%. The method was further applied to analyze the phytohormones in 14 monofloral raw honey samples and 3 commercial honey samples. The existence of 34 phytohormones was confirmed, including 14 cytokinins (CKs), 8 gibberellins (GAs), 5 brassinosteroids (BRs), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), jasmonoyl-leucine (JA-Leu), and jasmonoyl-phenylalanine (JA-Phe). In addition, the content and species of phytohormones varies in different kinds of honey. The study is beneficial to fully illustrate the phytohormone profile of honey and contributive to elucidate the mechanism of its nutritional and medicinal functions.

Pyrroloquinoline quinone enhances the resistance to oxidative stress and extends lifespan upon DAF-16 and SKN-1 activities in C. elegans

Pyrroloquinoline quinone (PQQ) is linked to fundamental biological processes such as mitochondrial biogenesis and lipid metabolism. PQQ may also function as an essential micronutrient during animal development. Recent studies have shown the therapeutic potential of PQQ for several age-related diseases due to its antioxidant capacity. However, whether PQQ can promote longevity is unknown. Here, we investigate the effects of PQQ on oxidative stress resistance as well as lifespan modulation in Caenorhabditis elegans. We find that PQQ enhances resistance to oxidative stress and extends the lifespan of C. elegans at optimal doses. The underlying molecular mechanism involves the increased activities of the primary lifespan extension transcriptional factors DAF-16/FOXO, the conserved oxidative stress-responsive transcription factor SKN-1/Nrf2, and upregulation of daf-16, skn-1 downstream targets including sod-3, hsp16.2, gst-1 and gst-10. Our findings uncover a novel role of PQQ in longevity, supporting PQQ as a possible dietary supplement for overall health improvement.

A rapid approach to investigate spatiotemporal distribution of phytohormones in rice

BACKGROUND

Phytohormones play crucial roles in almost all stages of plant growth and development. Accurate and simultaneous determination of multiple phytohormones enabled us to better understand the physiological functions and the regulatory networks of phytohormones. However, simultaneous determination of multiple phytohormones in plant is still a challenge due to their low concentrations, structural and chemical diversity, and complex matrix of plant tissues. Therefore, development of a simple and selective method for the simultaneous determination of multiple phytohormones is highly needed.

RESULTS

We developed a clean-up strategy for profiling of multiple phytohormones, which can overcome the challenge of structural and chemical diversity. By using a one-step dispersive solid-phase extraction (DSPE) combined with UPLC-MS/MS, 54 phytohormones including auxins, ABA, SA, JA, GAs and CKs were simultaneously analyzed from a single rice sample extract. Using the developed method, we investigated the spatiotemporal distribution of phytohormones in rice. The profiling of various tissues of rice at different growth stages revealed the complexity of metabolic regulation and allocations of phytohormone species.

CONCLUSION

A rapid one-step method was developed for the simultaneous analysis of six groups of phytohormones, including cytokinins, auxins, salicylic acid, jasmonates, abscisic acid and gibberellins in a single run, using UPLC-ESI-MS/MS. The proposed method was successfully applied to investigate spatiotemporal distribution of multiple phytohormones in rice. The spatiotemporal information obtained may be helpful for better understanding of phytohormones functions throughout life cycle of rice when integrated into transcriptome and other omics data.

Transcriptome analysis of grass carp (Ctenopharyngodon idella) fed with animal and plant diets

Numerous studies have been focused on the replacement of fish meal by other alternative protein sources. However, little is currently known about the molecular mechanism of utilization of diets with different protein sources in fish. Grass carp is a typical herbivorous fish. To elucidate the relationship between gene expression and utilization of animal and plant diets, transcriptome sequencing was performed in grass carp fed with chironomid larvae and duckweed. Grass carp fed with duckweed had significantly higher relative length of gut than those fed with chironomid larvae. 4435 differentially expressed genes were identified between grass carp fed with chironomid larvae and duckweed in brain, liver and gut, involved in cell proliferation and differentiation, appetite control, circadian rhythm, digestion and metabolism pathways. These pathways might play important roles in utilization of diets with different protein sources in grass carp. And the findings could provide a new insight into the replacement of fish meal in artificial diets.

Determination of Phytochelatins in Rice by Stable Isotope Labeling Coupled with Liquid Chromatography-Mass Spectrometry

A highly sensitive method was developed for the detection of phytochelatins (PCs) in rice by stable isotope labeling coupled with liquid chromatography-electrospray ionization-tandem mass spectrometry (IL-LC-ESI-MS/MS) analysis. A pair of isotope-labeling reagents [ω-bromoacetonylquinolinium bromide (BQB) and BQB-d(7)] were used to label PCs in plant sample and standard PCs, respectively, and then combined prior to LC/MS analysis. The heavy labeled standards were used as the internal standards for quantitation to minimize the matrix and ion suppression effects in MS analysis. In addition, the ionization efficiency of PCs was greatly enhanced through the introduction of a permanent charged moiety of quaternary ammonium of BQB into PCs. The detection sensitivities of PCs upon BQB labeling improved by 14-750-fold, and therefore, PCs can be quantitated using only 5 mg of plant tissue. Furthermore, under cadmium (Cd) stress, we found that the contents of PCs in rice dramatically increased with the increased concentrations and treatment time of Cd. It was worth noting that PC5 was first identified and quantitated in rice tissues under Cd stress in the current study. Taken together, this IL-LC-ESI-MS/MS method demonstrated to be a promising strategy in detection of PCs in plants with high sensitivity and reliability.

Transcriptome analysis of food habit transition from carnivory to herbivory in a typical vertebrate herbivore, grass carp Ctenopharyngodon idella

BACKGROUND

Although feeding behavior and food habit are ecologically and economically important properties, little is known about formation and evolution of herbivory. Grass carp (Ctenopharyngodon idella) is an ecologically appealing model of vertebrate herbivore, widely cultivated in the world as edible fish or as biological control agents for aquatic weeds. Grass carp exhibits food habit transition from carnivory to herbivory during development. However, currently little is known about the genes regulating the unique food habit transition and the formation of herbivory, and how they could achieve higher growth rates on plant materials, which have a relatively poor nutritional quality.

RESULTS

We showed that grass carp fed with duckweed (modeling fish after food habit transition) had significantly higher relative length of gut than fish before food habit transition or those fed with chironomid larvae (fish without transition). Using transcriptome sequencing, we identified 10,184 differentially expressed genes between grass carp before and after transition in brain, liver and gut. By eliminating genes potentially involved in development (via comparing fish with or without food habit transition), we identified changes in expression of genes involved in cell proliferation and differentiation, appetite control, circadian rhythm, and digestion and metabolism between fish before and after food habit transition. Up-regulation of GHRb, Egfr, Fgf, Fgfbp1, Insra, Irs2, Jak, STAT, PKC, PI3K expression in fish fed with duckweed, consistent with faster gut growth, could promote the food habit transition. Grass carp after food habit transition had increased appetite signal in brain. Altered expressions of Per, Cry, Clock, Bmal2, Pdp, Dec and Fbxl3 might reset circadian phase of fish after food habit transition. Expression of genes involved in digestion and metabolism were significantly different between fish before and after the transition.

CONCLUSIONS

We suggest that the food habit transition from carnivory to herbivory in grass carp might be due to enhanced gut growth, increased appetite, resetting of circadian phase and enhanced digestion and metabolism. We also found extensive alternative splicing and novel transcript accompanying food habit transition. These differences together might account for the food habit transition and the formation of herbivory in grass carp.

Role of fascin in the proliferation and invasiveness of esophageal carcinoma cells

Fascin, an actin-bundling protein, induces membrane protrusions and increases cell motility in various transformed cells. The overexpression of fascin in esophageal squamous cell carcinoma (ESCC) has been described only recently, but the roles and mechanism still remained unclear. Here, by using RNA interference (RNAi), we have stably silenced the expression of the fascin in EC109 cells, an ESCC cell line. Down-regulation of fascin resulted in a suppression of cell proliferation and as well as a decrease in cell invasiveness. Furthermore, we revealed that fascin might have functions in regulating tumor growth in vivo. The effect of fascin on cell invasiveness correlated with the activation of matrix metalloproteases such as MMP-2 and MMP-9. We examined that fascin down-expression also led to a decrease of c-erbB-2 and beta-catenin at the protein level. These results suggested that fascin might play crucial roles in regulating neoplasm progression of ESCC.

Arteriogenesis, a new concept of vascular adaptation in occlusive disease

The formation of collateral arteries as a process adaptive to arterial occlusion is now called 'arteriogenesis' to emphasize the difference to angiogenesis, the formation of capillaries by sprouting from pre-existent ones (W. Schaper, I. Buschmann. Cardiovasc Res 1999; 43: 835-7; I. Buschmann, W. Schaper. J Pathol 2000; 190: 338-42; D. Scholz et al. Virchows Arch 2000; 436: 257-70). The differences are that collaterals develop from pre-existing arterioles and that circulating monocytes adhere to endothelium that had been activated by the high shear stress generated by the large pressure differences between perfusion territories. Monocytes are the major producers of growth factors and of proteolytic enzymes that enable smooth muscle cells to migrate and divide. The nature of the growth factors remains uncertain. Neither FGF-1/2 nor VEGF is expressed on the transcriptional or translational level in collaterals proper and in the tissue surrounding them. Only FGF receptor 1 has a brief window of upregulation shortly after arterial occlusion. While transgenic overexpression of FGF-1 increases number and branching of arterioles, targeted disruption of FGF-1/2 does not negatively influence arteriogenesis. Cytokines that attract monocytes or prolong the life span of monocytes (MCP-1, GM CSF) are strong arteriogenic factors. Collateral vessels exhibit the same morphology whether they had formed in the heart, limbs or brain or in dogs, rabbits or mouse. They are tortuous because they also increase lengthwise in a restricted space. In animals larger than the mouse, they develop an intima, and initially, many arterioles participate in arteriogenesis, but only a few mature into large arterial channels which, when arterial occlusion had proceeded slowly enough, can replace the occluded artery to a significant proportion. Therapy with a single growth factor in animals with occluded femoral arteries significantly increases the speed of arteriogenesis but does not significantly increase the level of adaptation. It appears that the mastergene for arteriogenesis still awaits discovery.

A comparative study of telomerase activity and malignant phenotype in multistage carcinogenesis of esophageal epithelial cells induced by human papillomavirus

To examine certain characteristics of multistep carcinogenesis, we studied telomerase activity and malignant phenotypes in the immortal, premalignant and malignant stages of esophageal epithelial cells induced by HPV. An immortalized human fetal esophageal epithelial cell line (SHEE) was induced by E6E7 genes of human papillomavirus (HPV) type 18. Cells in the 10th passage, (SHEE10), 31st passage (SHEE31), 61st passage (SHEE61) and SHEE61A which were selected and expanded from anchorage-independent growth colonies of SHEE61, were examined as follows: cell morphology by electron-microscopy; the cell cycle by flow cytometry, telomerase activity by TRAP assay, tumorigenic detection including anchorage-independent growth by soft agar culture and tumor formation by inoculating cells into SCID and nude mice, and detection of HPV18 E6E7 oncoprotein by Western blot. The morphology of the SHEE10 cells exhibited good differentiation, the SHEE60 and SHEE61A cells were relatively poorly differentiated, and the SHEE31 cells were differentiated in two distinct ways. The telomerase was activated in SHEE31, SHEE61 and SHEE61A, but not in SHEE10 cells. SHEE61 and SHEE61A cells were weakened in contact-inhibition and increased in anchorage-independent growth. Inoculated into SCID and nude mice, the cells of the earlier two passages could not develop tumors; the SHEE61 developed one tumor in four SCID mice, but not in nude mice, and the SHEE61A cells developed tumors in both strains of immunodeficient mice. HPV18 E6E7 DNA detection by Western blotting was positive in all cell passages. In the process of carcinogenesis by HPV, the cells of SHEE31 are in an immortalized state with telomerase activity. The fact that SHEE61 cells remained immortalized and also demonstrated anchorage-independent growth, reveals premalignant character; the cells of SHEE61A exhibited malignant transformation with tumor formation in mice. The results revealed that the telomerase activity, anchorage-independent growth and tumor formation in nude mice are the indicators for immortalization, premalignancy and malignancy, respectively.

The genetic events of HPV-immortalized esophageal epithelium cells

We studied cytogenesis, telomere and telomerase, and c-myc, ras, bcl-2, and p53 genes of cells in the progressive process of immortal epithelial cells from embryonic esophagus induced by human papillomavirus (HPV). The SHEE cell line, established by us, consist of immortalized epithelial cells from the embryonic esophagus induced by genes E6E7 of HPV type 18. It was in initial malignant transformation when cultivated over 60 passages without co-carcinogens. Cells of the 10th, 31st, and 60th passages were represented in the progressive process within the immortal period. In these three stages of the cell line, the modal number of chromosome and karyotypes were analyzed. The telomere length was assayed by Southern blot methods, and the telomerase activity was analyzed by hTR and hTERT assay. C-myc, p53, bcl-2, ras genes were assayed by the multi-PCR method. The morphology of the 10th passage cells exhibited good differentiation, the 60th passage cells were relatively poorly differentiated, and the 31st passage cells differentiated in two distinct ways. The growth characteristics of the 31st and 60th passage cells were weakened at contact-inhibition and anchorage-dependent growth. Karyotypes of three cell passages belonged to hyperdiploid and hypotriploid with abnormal chromosomes +1, +3, +7, +9, +17, +18; del(1)(p32); der(4), t(4;?)(q31;?); der(5),t(5;?)(q31;?); der(13),t(13;13)(p11;q11) and others. Bimodal distribution of chromosomes with more aberrant chromosomes appeared in the 31st and 60th passage cells. Telomere length sharply shortened from normal fetal esophagus to the 10th and 31st passage step by step, but was stable from the 31st to the 60th passage and the telomerase activities measured were expressed at late two passages. p53 mutant was positive in three passages, c-myc was positive in the 31st and the 60th passage K-ras only in the last. The results reveal that changes of chromosomes, telomere length, telomerase activity and certain gene expressions are important events of HPV-immortalized esophageal epithelium cells. All of these changes occurred in dynamic progressive process. This cell line may be useful for the elucidation of the genetic mechanism of cellular immortalization.

[Cloning and the basic characteristics of a novel cDNA induced by ischemia and reperfusion]

OBJECTIVE

To identify and clone genes induced by ischemia and reperfusion.

METHODS

cDNA fragments responding to ischemia and reperfusion in porcine myocardium were isolated by mRNA differential display and then the cDNA library from porcine heart was screened. After cloning, sequencing, and hybridization, the basic characteristics of the gene were analyzed.

RESULTS

One cDNA fragment from a novel gene up-regulated by ischemia and reperfusion was identified and cloned subsequently; a novel full-length cDNA containing an open reading frame encoding 608 amino acid was obtained by screening the library. Sequencing results revealed that both DNA and amino acid sequences had no substantial homology to previously described DNA or protein sequences. Northern blot analysis confirmed that this gene expression in ischemia and reperfusion myocardium was significantly increased, and the expression was also able to be detected in normal porcine heart, liver, lung, kidney, spleen, intestine, brain, and skeletal muscle. Southern blot analysis clearly showed that this novel gene had high evolutional conservation in human beings, pigs, rabbits, and mice.

CONCLUSION

The cloned gene is a novel one induced by ischemia and reperfusion, and it may play a very important role in the response to ischemia and reperfusion.

[Expression and cloning of two novel genes induced by ischemia and reperfusion]

OBJECTIVE

To identify and clone the differentially expressed genes in brief ischemia and reperfusion myocardium.

METHODS

Ischemia and reperfusion were induced by repeated brief ligation of the porcine left anterior descending coronary artery. Total RNA which was isolated from myocardium subjected ischemia and reperfusion was used for mRNA differential display. After cloning and sequencing the cDNA fragments which showed change in expression, their expression were further confirmed by Northern-Blot analysis.

RESULTS

Two differentially expressed cDNAs (W12 and W28) were identified and cloned. Their expression were subsequently confirmed to be truly differentially expressed. The expression of both genes in ischemia and reperfusion myocardium was obvious higher than that in nonischemia and reperfusion: W12 expression level was 2-fold (P < 0.05), and W28 expression level 1.9-fold (P < 0.05). In addition, mRNAs of W12 and W28 were existed in all tested organs including heart, liver, lung, kidney, spleen, intestine, brain and skeletal muscle. DNA sequencing analysis showed that there was no homology between W12, W28 and known genes, implying that they would represent novel gene respectively.

CONCLUSION

Two novel genes induced by ischemia and reperfusion are identified, cloned and confirmed.

Connexin37, not Cx40 and Cx43, is induced in vascular smooth muscle cells during coronary arteriogenesis

W.-J. Cai, S. Koltai, E. Kocsis, D. Scholz, W. Schaper and J. Schaper. Connexin37, not Cx40 and Cx43, is Induced in Vascular Smooth Muscle Cells During Coronary Arteriogenesis. Journal of Molecular and Cellular Cardiology (2001) 33, 957-967. The hypothesis that an altered expression of gap junction (GJ) proteins, connexin37 (Cx37), Cx40 and Cx43 will contribute to adaptive arteriogenesis was tested in growing coronary collateral vessels (CV) of the dog heart by immunoconfocal microscopy and transmission electron microscopy (TEM). We found that: (1) in the normal coronary system Cx37 and Cx40 were only expressed in endothelial cells (EC) from artery to capillary; (2) during collateral growth Cx37 was significantly induced in smooth muscle cells (SMC) from small-large arteries to precapillary arterioles (Ø=15 microm), while Cx40 was still only present in EC; (3) both homogeneous and heterogeneous distribution of Cx37 was observed in normal vessels (NV) and growing vessels (GV); (4) in mature vessels (MV), Cx37 was downregulated, similar to NV; (5) dual immunostaining revealed an inverse correlation between expression of Cx37 and desmin in GV occurring prior to downregulation of alpha-smooth actin and calponin; (6) Cx43 was undetectable in any vascular cells, both in NV and GV; (7) GJ were not found in SMC by TEM. Our data for the first time show the profile of connexin expression in the coronary system and provide evidence for existence of GJ proteins in capillaries. It is a novel finding that an altered expression of Cx37 is characteristic of adaptive arteriogenesis in the dog heart and may be used as a marker of vascular growth. Induced Cx37 may be an early signal indicating that SMC are responding to haemodynamic changes, i.e. increased shear stress.

The alteration of mitochondria is an early event of arsenic trioxide induced apoptosis in esophageal carcinoma cells

It is accepted that inorganic arsenic trioxide is an inducer of apoptosis for many types of cancer. Our previous studies have demonstrated that arsenic trioxide induces apoptosis of esophageal carcinoma cells. Administration of arsenic trioxide results in the inhibition of growth and survival of tumor cells. Esophageal carcinoma cells treated with arsenic trioxide for 3 days demonstrated a typical morphological appearance of apoptosis. To further examine molecular mechanism of arsenic trioxide induced apoptosis of esophageal carcinoma cells, we have investigated the early changes of the apoptotic cell induced by arsenic trioxide. Our results indicated that arsenic trioxide induced apoptosis of esophageal carcinoma cells occurs as early as 2 h after treatment. Annexin-v staining has further proved that the phosphatidylserine is exposed at 2 h. The early morphological change of arsenic trioxide treated cells was in the mitochondria. Arsenic trioxide treated cells displayed aggregated mitochondria. It induces accumulation of high electron-density amorphous substances, swollen and disruption of mitochondria in oesophageal carcinoma cells after 2 h treatment. The alteration of mitochondria induced by arsenic trioxide seems to occur before the condensation of chromatin. Thus, our data demonstrated that the primary target of arsenic trioxide induced apoptosis of esophageal carcinoma cells may be the mitochondria. It is possible that arsenic trioxide is a mitochondriotoxic agent.

Estrogen receptor immunoreactivity within subregions of the rat forebrain: neuronal distribution and association with perikarya containing choline acetyltransferase

Administration of the neuroactive steroid hormone estrogen has been shown to effect cholinergic basal forebrain neuronal function. Antibodies directed against the estrogen receptor alpha (ERalpha) revealed dark (type 1) and light (type 2) nuclear positive neurons within the islands of Calleja, endopiriform nucleus, lateral septum, subfields of the cholinergic basal forebrain, bed nucleus of the stria terminalis, striohypothalamic region, medial preoptic region, periventricular, ventromedial, arcuate and tuberal mammillary nuclei of the hypothalamus, reuniens and anterior medial thalamic nuclei, amygdaloid complex, piriform cortex and subfornical organ. In contrast, only a few scattered ERalpha labeled neurons were found in cortex and hippocampus. ERalpha stained cell bodies were not seen in the striatum. Counts of ERalpha labeled neurons in intact female rats revealed significantly more type 2 neurons within the basal forebrain subfields. Quantitation of ERalpha immunoreactive neurons revealed a significant decrease in the relative number of type 1 neurons within the medial septum (MS), horizontal limb of the diagonal band (HDB) and substantia innominata/nucleus basalis (SI/NB) following ovariectomy. Quantitation following choline acetyltransferease (ChAT) immunohistochemistry revealed a significant decrease in the number of ChAT positive neurons within the MS, HDB and SI/NB, but not VDB following ovariectomy. Following ovx, the percentage of double labeled cholinergic basal forebrain neurons also declined significantly within the MS, VDB, HDB and SI/NB. These observations suggest that estrogen effects a subpopulation of cholinergic basal forebrain neurons and may provide insight into the biologic actions of this steroid in Alzheimer's disease.

Arsenic trioxide induces apoptosis of oesophageal carcinoma in vitro

The arsenic compounds in traditional Chinese medicine have been recorded to have therapeutic effects on the treatment of psoriasis, syphilis, rheumatosis and a number of malignant tumours. Recent studies showed that arsenic trioxide can induce clinical remission in patients with acute promyelocytic leukemia, including those who have relapsed after retinoic acid treatment. however, the mechanism of how arsenic trioxide targets tumour cells is not clearly understood. We have examined the effects of arsenic trioxide on oesophageal carcinoma cell line EC8712. Our results demonstrated that the growth and survival of tumour cells were markedly inhibited by arsenic trioxide. The half dose effect (ED50) was at the concentration of 1 microM. Electron microscopic study demonstrated that EC8712 tumour cells treated with arsenic trioxide display a typical morphological appearance of apoptosis, including chromatin condensation and fragmentation of the nuclei. In contrast, no apoptotic features were observed in tumour cells without arsenic trioxide treatment. TUNEL assay also showed the biological features of apoptosis in cells treated with arsenic trioxide. Flow cytometry analyses showed that apoptotic peak was identified in arsenic trioxide treated cells but not in the control. Apoptotic cells in arsenic trioxide treated group account for 35% of total cell populations after three days treatment at a dose of 3 microM. In short, our results suggested that the anticancer effect of arsenic trioxide is due, at least in part, to the induction of apoptosis in cancer cells.

Vascular remodeling and altered protein expression during growth of coronary collateral arteries

The cellular mechanism of growth of coronary collateral vessels (adaptive arteriogenesis) is still poorly understood. To define a possible role of an altered expression pattern of cellular and matrix proteins in this process we implanted a constricting device around the left circumflex artery in 25 canine hearts and sacrificed the animals at the time of initiation (3 weeks), high activity (6 weeks) and discontinuation (8 weeks) of vessel growth. Methods were electron microscopy, labeling with Ki-67, the TUNEL method and immunofluorescence with confocal laser microscopy. As described earlier, the collateral vessels increased in wall thickness by the formation of a neointima without luminal narrowing. We report here for the first time that extensive vascular remodeling including migration, proliferation and apoptosis in all cell types takes place during the growth phase but not in more mature vessels. The most obvious difference with normal vessels is the reiteration of an embryonal expression pattern in smooth muscle cells of the neointima which includes a significant reduction of desmin and alpha-smooth muscle actin, calponin and vinculin. Fibronectin as a promoter of migration and adhesion was abundant, its antagonist tenascin and chondroitin sulfate showed patchy localization. A completely new finding in arteriogenesis is the involvement of mast cells releasing histamine and serotonin and probably cytokines. Vascular protein expression returned to almost normal at 8 weeks indicating cessation of remodeling. We conclude that in collateral vessel development an altered cellular and matrix protein expression is involved in a drastic case of positive vascular remodeling finally resulting in mature vessels 20-fold increased in size which are capable of maintaining the functional and structural integrity of the myocardium at risk.

Hibernating myocardium: an incomplete adaptation to ischemia

BACKGROUND

We tested the hypothesis that hibernating myocardium represents an incomplete adaptation to a reduced myocardial oxygen supply.

METHODS AND RESULTS

In 38 patients, areas of hibernating myocardium were identified by angiography, multigated radionuclide ventriculography, thallium scintigraphy with reinjection, and low-dose dobutamine echocardiography. Biopsies removed at cardiac surgery showed structural degeneration characterized by a reduced protein and mRNA expression and disorganization of the contractile and cytoskeletal proteins myosin, actin, desmin, titin, alpha-actinin, and vinculin by electron microscopy, immunohistochemistry, and in situ hybridization. Additionally, an increased amount of extracellular matrix proteins resulting in a significant degree of reparative fibrosis was present. Dedifferentiation, ie, expression of fetal proteins, was absent. Apoptosis indicating suicidal cell death was found by the terminal deoxynucleotidyl transferase end-labeling method and electron microscopy. Radionuclide ventriculography showed improvement of regional function at 3 months postoperatively compared with preoperative values (mean values, 23.5% and 48%, respectively), and the echocardiographic wall-motion score index decreased from 3.4 to 1.8. The degree of severity of the morphological changes (three stages) correlated well with the extent of postoperative functional recovery: more advanced clinical improvement was observed in patients with slight and moderate morphological degeneration (stages 1 and 2), but recovery was only partial in severe degeneration (stage 3).

CONCLUSIONS

Cellular degeneration rather than adaptation is present in hibernating myocardium. The consequence is progressive diminution of the chance for complete structural and functional recovery after restoration of blood flow. The practical consequence from this study should be early revascularization in patients showing areas of hibernating myocardium.

A stable L-arginine-dependent relaxing factor released from cytotoxic-activated macrophages

It has been known that cytotoxic-activated macrophages release an unstable vasorelaxing substance, nitric oxide. We have found that a more stable relaxing factor is released from those cells. This factor seems to be synthesized from L-arginine. It acts through the activation of soluble guanylate cyclase without affecting membrane potential. It has little charge at nearly neutral pH, and its molecular weight is < 500.

Clinical safety of long-term administration of gossypol in 32 cases

Thirty-two men have taken gossypol acetic acid for long periods (6-10 years). The users had side effects during the entire course. Serum glutamate-pyruvate transaminase (SGPT) was increased in 3 cases and persisted for more than a year. There was a downward trend in plasma potassium level during the loading phase. But, hypokalaemic paralysis did not occur. Results of semen analysis showed that the shorter the duration of gossypol administration, the higher the recovery rate. The positive rate of Et formation of peripheral blood lymphocytes was remarkably decreased. After cessation of gossypol for 6-12 months, Et formation of the group stopping drug showed a recovering trend, but had not recovered to normal. The IgG level in the serum of treatment group was decreased, but was still within normal range.