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1.
Int J Biol Macromol ; 269(Pt 2): 132188, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38723808

ABSTRACT

Biodegradable polylactic acid (PLA)/nano­zinc oxide (ZnO)/additives non-woven slices were prepared by melt blending method. The effects of antibacterial agent nano-ZnO, antioxidant pentaerythrityl tetrakis-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (1010), and chain extender multi-functional epoxy (ADR), on the melt flow rate, mechanical properties, thermal stabilities and micromorphology of the slices were investigated. The melt flow rate decreased from 26.94 g/10 min to 17.76 g/10 min, and the tensile strength increased from 10.518 MPa to 30.427 MPa with the increase of nano-ZnO and additives content. The slices were further spunbonded. The wettability and antibacterial properties of PLA/nano-ZnO/additives antibacterial non-wovens were studied, and the antibacterial action mechanism was clarified. The results showed that the biodegradable PLA/nano-ZnO/additives antibacterial non-wovens were prepared continuously successfully. The prepared non-woven fabrics exhibited good hydrophobicity and antibacterial properties. The mechanism study shows that zinc ion produced by nano-ZnO and photocatalytic reaction make the fabrics have good antibacterial activity at low nano-ZnO content. When nano-ZnO concentration reaches 1.5 wt%, the antibacterial rate against Escherichia coli and Staphylococcus aureus reaches 98.52 % and 98.13 %, respectively.


Subject(s)
Anti-Bacterial Agents , Polyesters , Zinc Oxide , Zinc Oxide/chemistry , Zinc Oxide/pharmacology , Polyesters/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Staphylococcus aureus/drug effects , Escherichia coli/drug effects , Microbial Sensitivity Tests , Tensile Strength , Wettability
2.
Sci Rep ; 14(1): 9857, 2024 04 29.
Article in English | MEDLINE | ID: mdl-38684835

ABSTRACT

The aim of this study was to investigate the value of diffusion-weighted imaging (DWI) as a potential non-gadolinium alternative for promptly assessing the hyperacute outcome of magnetic resonance-guided focused ultrasound (MRgFUS) treatment for uterine fibroids. In this retrospective study we included 65 uterine fibroids from 44 women, who underwent axial DWI (b-value: 800 s/mm2) and contrast-enhanced (CE) MR within 15 min post-ablation. Two blinded observers independently reviewed the DWI findings of ablated necrotic lesions and measured their volumes on DWI and CE images. The post-ablation DWI images revealed clear depiction of ablative necrotic lesions in all fibroids, which were classified into two types: the bull's eye sign (type 1) and the bright patch sign (type 2). The inter-observer intraclass correlation coefficient for classifying DWI signal types was 0.804 (p < 0.001). Volumetric analysis of ablated necrosis using DWI and CE T1-weighted imaging showed no significant variance, nor did the non-perfused volume ratios (all p > 0.05). Bland-Altman analysis revealed a mean difference of 2.38% and 1.71% in non-perfused volume ratios between DWI and CE, with 95% limits of agreement from - 19.06 to 23.82% and - 18.40 to 21.82%, respectively. The findings of this study support the potential of DWI as a viable non-gadolinium alternative for evaluating the hyperacute outcomes of MRgFUS ablation in uterine fibroids.


Subject(s)
Diffusion Magnetic Resonance Imaging , High-Intensity Focused Ultrasound Ablation , Leiomyoma , Humans , Female , Leiomyoma/diagnostic imaging , Leiomyoma/surgery , Leiomyoma/pathology , Diffusion Magnetic Resonance Imaging/methods , Adult , Middle Aged , Retrospective Studies , High-Intensity Focused Ultrasound Ablation/methods , Treatment Outcome , Uterine Neoplasms/diagnostic imaging , Uterine Neoplasms/surgery , Uterine Neoplasms/pathology , Contrast Media
3.
PLoS One ; 18(6): e0287090, 2023.
Article in English | MEDLINE | ID: mdl-37310940

ABSTRACT

OBJECTIVE: The purpose of this study was to investigate the relationship between bedtime at night and the risk of diabetes in adults. METHODS: We extracted data from 14,821 target subjects from the NHANES database for a cross-sectional study. The data on bedtime came from the question in the sleep questionnaire: "What time do you usually fall asleep on weekdays or workdays?". Diabetes was defined as fasting blood sugar ≥ 126mg/dL, or glycohemoglobin ≥ 6.5%, or 2-hour Oral Glucose Tolerance Test blood sugar ≥ 200mg/dL, or taking hypoglycemic agent and insulin, or self-reported diabetes mellitus. A weighted multivariate logistic regression analysis was conducted to explore the relationship between bedtime at night and diabetes in adults. RESULTS: From 19:00 to 23:00, a significantly negative association can be found between bedtime and diabetes(OR, 0.91 [95%CI, 0.83, 0.99]). From 23:00 to 02:00, The relationship between the two was positive(OR, 1.07 [95%CI, 0.94, 1.22]), nevertheless, the P values was not statistically significant(p = 0.3524). In subgroup analysis, from 19:00-23:00, the relationship was negative across genders, and in males, the P-values were still statistically significant(p = 0.0414). From 23:00-02:00, the relationship was positive across genders. CONCLUSION: Earlier bedtime (before 23:00) increased the risk of developing diabetes. And this effect was not significantly different between male and female. For bedtime between 23:00-2:00, there was a trend of increasing the risk of diabetes as the bedtime was delayed.


Subject(s)
Diabetes Mellitus , Sleep , Adult , Female , Humans , Male , Cross-Sectional Studies , Diabetes Mellitus/epidemiology , Nutrition Surveys , United States/epidemiology , Time Factors , Risk Factors , Middle Aged
4.
Commun Biol ; 6(1): 457, 2023 04 25.
Article in English | MEDLINE | ID: mdl-37100819

ABSTRACT

In rice (Oryza sativa) tissue culture, callus can be induced from the scutellum in embryo or from the vasculature of non-embryonic organs such as leaves, nodes, or roots. Here we show that the auxin signaling pathway triggers cell division in the epidermis of the scutellum to form an embryo-like structure, which leads to callus formation. Our transcriptome data show that embryo-, stem cell-, and auxin-related genes are upregulated during scutellum-derived callus initiation. Among those genes, the embryo-specific gene OsLEC1 is activated by auxin and involved in scutellum-derived callus initiation. However, OsLEC1 is not required for vasculature-derived callus initiation from roots. In addition, OsIAA11 and OsCRL1, which are involved in root development, are required for vasculature-derived callus formation but not for scutellum-derived callus formation. Overall, our data indicate that scutellum-derived callus initiation is regulated by an embryo-like development program, and this is different from vasculature-derived callus initiation which borrows a root development program.


Subject(s)
Oryza , Plant Roots/metabolism , Indoleacetic Acids/pharmacology , Indoleacetic Acids/metabolism , Signal Transduction
5.
STAR Protoc ; 4(2): 102156, 2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36917608

ABSTRACT

We present a protocol to establish a synthetic symbiosis between the mCherry-expressing Sodalis praecaptivus and the grain weevil host, Sitophilus zeamais. We describe steps to isolate grain weevil eggs, followed by microinjecting the bacterial symbiont into insect eggs using a modified Drosophila injection protocol, which leads to localization of bacteria in female insect ovaries. We then detail larval transplantation and visualization of bacteria in live insects using a fluorescence dissection microscope to assess the transgenerational transmission to offspring in weevils. For complete details on the use and execution of this protocol, please refer to Su et al. (2022).1.

6.
Curr Biol ; 32(18): 3925-3938.e6, 2022 09 26.
Article in English | MEDLINE | ID: mdl-35963240

ABSTRACT

Many insects maintain mutualistic associations with bacterial endosymbionts, but little is known about how they originate in nature. In this study, we describe the establishment and manipulation of a synthetic insect-bacterial symbiosis in a weevil host. Following egg injection, the nascent symbiont colonized many tissues, including prototypical somatic and germinal bacteriomes, yielding maternal transmission over many generations. We then engineered the nascent symbiont to overproduce the aromatic amino acids tyrosine and phenylalanine, which facilitate weevil cuticle strengthening and accelerated larval development, replicating the function of mutualistic symbionts that are widely distributed among weevils and other beetles in nature. Our work provides empirical support for the notion that mutualistic symbioses can be initiated in insects by the acquisition of environmental bacteria. It also shows that certain bacterial genera, including the Sodalis spp. used in our study, are predisposed to develop these associations due to their ability to maintain benign infections and undergo vertical transmission in diverse insect hosts, facilitating the partner-fidelity feedback that is critical for the evolution of obligate mutualism. These experimental advances provide a new platform for laboratory studies focusing on the molecular mechanisms and evolutionary processes underlying insect-bacterial symbiosis.


Subject(s)
Symbiosis , Weevils , Amino Acids, Aromatic , Animals , Bacteria/genetics , Insecta/microbiology , Phenylalanine , Phylogeny , Tyrosine , Weevils/genetics
7.
Front Microbiol ; 12: 714409, 2021.
Article in English | MEDLINE | ID: mdl-34456895

ABSTRACT

Dengue virus (DENV) is a small envelope virus of Flaviviridae that is mainly transmitted by Aedes aegypti and Aedes albopictus. It can cause dengue fever with mild clinical symptoms or even life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). At present, there are no specific drugs or mature vaccine products to treat DENV. microRNAs (miRNAs) are a class of important non-coding small molecular RNAs that regulate gene expression at the post-transcriptional level. It is involved in and regulates a series of important life processes, such as growth and development, cell differentiation, cell apoptosis, anti-virus, and anti-tumor. miRNAs also play important roles in interactions between host and viral genome transcriptomes. Host miRNAs can directly target the genome of the virus or regulate host factors to promote or inhibit virus replication. Understanding the expression and function of miRNAs during infection with DENV and the related signal molecules of the miRNA-mediated regulatory network will provide new insights for the development of miRNA-based therapies.

8.
Biomed Res Int ; 2021: 4853632, 2021.
Article in English | MEDLINE | ID: mdl-33623781

ABSTRACT

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is an accurate and convenient method for mRNA quantification. Selection of optimal reference gene(s) is an important step in RT-qPCR experiments. However, the stability of housekeeping genes in spinach (Spinacia oleracea) under various abiotic stresses is unclear. Evaluating the stability of candidate genes and determining the optimal gene(s) for normalization of gene expression in spinach are necessary to investigate the gene expression patterns during development and stress response. In this study, ten housekeeping genes, 18S ribosomal RNA (18S rRNA), actin, ADP ribosylation factor (ARF), cytochrome c oxidase subunit 5C (COX), cyclophilin (CYP), elongation factor 1-alpha (EF1α), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone H3 (H3), 50S ribosomal protein L2 (RPL2), and tubulin alpha chain (TUBα) from spinach, were selected as candidates in roots, stems, leaves, flowers, and seedlings in response to high temperature, CdCl2, NaCl, NaHCO3, and Na2CO3 stresses. The expression of these genes was quantified by RT-qPCR and evaluated by NormFinder, BestKeeper, and geNorm. 18S rRNA, actin, ARF, COX, CYP, EF1α, GAPDH, H3, and RPL2 were detected as optimal reference genes for gene expression analysis of different organs and stress responses. The results were further confirmed by the expression pattern normalized with different reference genes of two heat-responsive genes. Here, we optimized the detection method of the gene expression pattern in spinach. Our results provide the optimal candidate reference genes which were crucial for RT-qPCR analysis.


Subject(s)
Genes, Plant/genetics , Real-Time Polymerase Chain Reaction/standards , Spinacia oleracea/genetics , Stress, Physiological/genetics , DNA, Plant/genetics , Gene Expression Profiling/methods , Gene Expression Profiling/standards , Genes, Essential/genetics , Real-Time Polymerase Chain Reaction/methods , Transcriptome/genetics
9.
J Microbiol ; 59(3): 324-331, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33624269

ABSTRACT

As a special type of noncoding RNA, circular RNAs (circRNAs) are prevalent in many organisms. They can serve as sponges for microRNAs and protein scaffolds, or templates for protein translation, making them linked to cellular homeostasis and disease progression. In recent years, circRNAs have been found to be abnormally expressed during the processes of viral infection and pathogenesis, and can help a virus escape the immune response of a host. Thus, they are now considered to play important functions in the invasion and development of viruses. Moreover, the potential application of circRNAs as biomarkers of viral infection or candidates for therapeutic targeting deserves consideration. This review summarizes circRNAs in the transcriptome, including their classification, production, functions, and value as biomarkers. This review paper also describes research progress on circRNAs in viral infection (mainly hepatitis B virus, HIV, and some human herpes viruses) and aims to provide new ideas for antiviral therapies targeting circRNAs.


Subject(s)
RNA, Circular/genetics , RNA, Viral/genetics , Virus Diseases/genetics , Viruses/genetics , Animals , Genome, Viral , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , RNA, Circular/metabolism , RNA, Viral/metabolism , Virus Diseases/metabolism , Virus Diseases/virology , Viruses/metabolism
10.
J Econ Entomol ; 114(1): 225-230, 2021 02 09.
Article in English | MEDLINE | ID: mdl-33295959

ABSTRACT

In recent years, Protaetia brevitarsis Lewis has gradually become an important pest of several crops including grape (Vitis vinifera L.) and peach (Amygdalus persica L.) in Xinjiang, China. Toward improving trapping efficacy as part of a management program, various colors, types, and placement of traps and the use of an attractant were evaluated in field and laboratory studies. Laboratory color-choice tests and field tests indicated that P. brevitarsis adults preferred red. In trap placement tests, more adults were captured on traps placed 1 or 1.5 m above the ground and on top of the horizontal grape canopy. Before grape ripening, more adults were captured in traps placed in a 0.5-m border around the outside edge of the vineyard; during grape ripening, more were caught within the vineyard. Newly designed traps that were red, with a triangular baffle and a landing plate, were more efficient than traditional bucket-shaped traps. When P. brevitarsis adults were trapped and killed from June to July 2018, the population of P. brevitarsis adults in August to early September 2018 was significantly lower than in August to early September 2017, when adults had not been trapped and killed in the prior 2 mo.


Subject(s)
Coleoptera , Animals , China , Color , Insect Control
11.
Mol Plant ; 14(2): 285-297, 2021 02 01.
Article in English | MEDLINE | ID: mdl-33221411

ABSTRACT

Auxin plays a critical role in lateral root (LR) formation. The signaling module composed of auxin-response factors (ARFs) and lateral organ boundaries domain transcription factors mediates auxin signaling to control almost every stage of LR development. Here, we show that auxin-induced degradation of the APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factor ERF13, dependent on MITOGEN-ACTIVATED PROTEIN KINASE MPK14-mediated phosphorylation, plays an essential role in LR development. Overexpression of ERF13 results in restricted passage of the LR primordia through the endodermal layer, greatly reducing LR emergence, whereas the erf13 mutants showed an increase in emerged LR. ERF13 inhibits the expression of 3-ketoacyl-CoA synthase16 (KCS16), which encodes a fatty acid elongase involved in very-long-chain fatty acid (VLCFA) biosynthesis. Overexpression of KCS16 or exogenous VLCFA treatment rescues the LR emergence defects in ERF13 overexpression lines, indicating a role downstream of the auxin-MPK14-ERF13 signaling module. Collectively, our study uncovers a novel molecular mechanism by which MPK14-mediated auxin signaling modulates LR development via ERF13-regulated VLCFA biosynthesis.


Subject(s)
Arabidopsis Proteins/metabolism , Fatty Acids/biosynthesis , Indoleacetic Acids/metabolism , Mitogen-Activated Protein Kinase 14/metabolism , Plant Roots/growth & development , Signal Transduction , Transcription Factors/metabolism , Phosphorylation , Plant Roots/metabolism , Protein Binding , Proteolysis
12.
J Exp Bot ; 71(20): 6555-6570, 2020 10 22.
Article in English | MEDLINE | ID: mdl-32725150

ABSTRACT

Reactive oxygen species (ROS) are plant metabolic and signaling molecules involved in responses to various external stresses, but the existence of ROS receptors and how plants respond to ROS remain largely unknown. Here we report that the plasma membrane-localized phospholipase D δ (PLDδ) protein is crucial for sensing heat shock-induced ROS to initiate reorganization of guard cell microtubules in Arabidopsis cotyledons. Heat shock of wild-type Arabidopsis cotyledons stimulated ROS production which disrupted microtubule organization and induced stomatal closure, whereas this process was markedly impaired in pldδ mutants. Moreover, wild-type PLDδ, but not the Arg622-mutated PLDδ, complemented the pldδ phenotypes in heat shock-treated plants. ROS activated PLDδ by oxidizing cysteine residues, an action that was required for its functions in ROS-induced depolymerization of guard cell microtubules, stomatal closure, and plant thermotolerance. Additionally, lipid profiling reveals involvement of microtubule organization in the feedback regulation of glycerolipid metabolism upon heat stress. Together, our findings highlight a potential mechanosensory role for PLDδ in regulating the dynamic organization of microtubules and stomatal movement, as part of the ROS-sensing pathway, during the response to external stresses.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Abscisic Acid , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Heat-Shock Response , Microtubules , Phospholipase D , Plant Stomata , Reactive Oxygen Species
13.
Plant Cell Rep ; 39(6): 825-837, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32219503

ABSTRACT

KEY MESSAGE: AGC1-4 kinase plays a crucial role in the regulation of seeds by mediating cell proliferation and embryo development in Arabidopsis. Seed size is a crucial factor to influence final seed yield in plants. However, the molecular mechanisms that set final seed size still need to be investigated. Here, we identified a novel AGC protein kinase AGC1-4, which encodes a serine-threonine kinase, belongs to the AGC VIIIa subfamily. The seeds of agc1-4 mutant were significantly larger than that in the wild type. Overexpression of the AGC1-4 gene reduced seed size. Regulation of AGC1-4 seed size is dependent on embryonic cell number. To further determine AGC1-4 functions in seed size, we analyzed AGC1-4 phosphoproteins using label-free quantitative phosphoproteomics coupled to the transcriptome of agc1-4 using RNA sequencing (RNA-seq). The RNA-seq analysis showed 1611 differentially expressed genes (DEGs), which cover a wide range of functions, such as cell cycle and embryo development. The 262 unique phosphoproteins were detected by phosphoproteomics analysis. The differentially phosphorylated proteins were involved in cell cycle and post-embryo development. Overlay of the RNA-seq and phosphoproteomics results demonstrated AGC1-4 as an important factor that influences seed size by mediating cell proliferation and embryo development. The results in this study provide novel data on the serine-threonine kinase AGC1-4 mediating seed size in Arabidopsis.


Subject(s)
Arabidopsis/genetics , Arabidopsis/metabolism , Protein Kinases/genetics , Protein Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Seeds/genetics , Seeds/metabolism , Arabidopsis/embryology , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Cell Cycle , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Plants, Genetically Modified , Seeds/cytology , Seeds/growth & development , Sequence Analysis, RNA , Transcriptome
14.
aBIOTECH ; 1(3): 194-204, 2020 Jul.
Article in English | MEDLINE | ID: mdl-36303567

ABSTRACT

Plant stem cells are a small group of cells with a self-renewal capacity and serve as a steady supply of precursor cells to form new differentiated tissues and organs in plants. Root stem cells and shoot stem cells, which are located in the root apical meristem and in the shoot apical meristem, respectively, play a critical role in plant longitudinal growth. These stem cells in shoot and root apical meristems remain as pluripotent state throughout the lifespan of the plant and control the growth and development of plants. The molecular mechanisms of initiation and maintenance of plant stem cells have been extensively investigated. In this review, we mainly discuss how the plant phytohormones, such as auxin and cytokinin, coordinate with the key transcription factors to regulate plant stem cell initiation and maintenance in root and shoot apical meristems. In addition, we highlight the common regulatory mechanisms of both root and shoot apical meristems.

15.
Mol Microbiol ; 103(6): 958-972, 2017 03.
Article in English | MEDLINE | ID: mdl-27987256

ABSTRACT

Many bacteria utilize two-component systems consisting of a sensor kinase and a transcriptional response regulator to detect environmental signals and modulate gene expression for adaptation. The response regulator PhoP and its cognate sensor kinase PhoQ compose a two-component system known for its role in responding to low levels of Mg2+ , Ca2+ , pH and to the presence of antimicrobial peptides and activating the expression of genes involved in adaptation to host association. Compared with their free-living relatives, mutualistic insect symbiotic bacteria inhabit a static environment where the requirement for sensory functions is expected to be relaxed. The insect symbiont, Sodalis glossinidius, requires PhoP to resist killing by host derived antimicrobial peptides. However, the S. glossinidius PhoQ was found to be insensitive to Mg2+ , Ca2+ and pH. Here they show that Sodalis praecaptivus, a close non host-associated relative of S. glossinidius, utilizes a magnesium sensing PhoP-PhoQ and an uncharacterized MarR-like transcriptional regulator (Sant_4061) to control antimicrobial peptide resistance in vitro. While the inactivation of phoP, phoQ or Sant_4061 completely retards the growth of S. praecaptivus in the presence of an antimicrobial peptide in vitro, inactivation of both phoP and Sant_4061 is necessary to abrogate growth of this bacterium in an insect host.


Subject(s)
Antimicrobial Cationic Peptides/pharmacology , Bacterial Proteins/genetics , Enterobacteriaceae/growth & development , Weevils/microbiology , Animals , Bacterial Proteins/metabolism , Base Sequence , Calcium/metabolism , Enterobacteriaceae/genetics , Enterobacteriaceae/metabolism , Gene Expression Regulation, Bacterial , Gene Knockout Techniques , High-Throughput Nucleotide Sequencing , Magnesium/metabolism , Sequence Analysis, DNA , Signal Transduction/physiology , Symbiosis , Transcription, Genetic/physiology
16.
Can J Ophthalmol ; 47(1): 11-5, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22333844

ABSTRACT

OBJECTIVE: The relationship between cataract surgery wait times and rates of surgery was investigated to determine whether wait times correlate with rates of surgery. DESIGN: Cross-sectional study. PARTICIPANTS: We collected 2 Ontario registries for cataract surgeries: (i) Cancer Care Ontario wait time registry; and (ii) The Ontario Health Insurance Plan billing records. METHODS: Both registries were used to determine whether wait times correlated with rates of surgery, and the data were then stratified by region of the province, priority (severity) of cases, age, and sex. RESULTS: The total number of surgeries performed between April 2, 2007, and March 31, 2008, was 65,520. The overall mean number of wait days was 69.8 days; the mean patient age was 72.5 years; and the surgery rate was 540.3 per 100,000 members of the population. For high-priority cases (priorities 1 and 2), there was a very weak inverse correlation (p = -0.27 and -0.21) between wait time and surgery rate, whereas the overall correlation between wait time and surgical rate was close to zero in both databases, regardless of the region, the patients' ages, and the patients' genders. CONCLUSIONS: This study demonstrates a very weak correlation between wait times for and rates of cataract surgery, and this should be a concern for policy makers. Further study is needed to see whether this null relationship persists over time and whether it exists for other monitored wait time procedures. Reasons for this null relationship will have to be determined and remedied as the use of wait times becomes a more widespread outcome in Canadian Healthcare.


Subject(s)
Cataract Extraction/statistics & numerical data , Outcome Assessment, Health Care , Waiting Lists , Aged , Aged, 80 and over , Cataract/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Ontario/epidemiology , Patient Acceptance of Health Care/statistics & numerical data , Registries , Retrospective Studies
17.
Mol Plant ; 4(4): 616-25, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21357646

ABSTRACT

Plant hormones regulate many aspects of plant growth and development. Both auxin and cytokinin have been known for a long time to act either synergistically or antagonistically to control several significant developmental processes, such as the formation and maintenance of meristem. Over the past few years, exciting progress has been made to reveal the molecular mechanisms underlying the auxin-cytokinin action and interaction. In this review, we shall briefly discuss the major progress made in auxin and cytokinin biosynthesis, auxin transport, and auxin and cytokinin signaling. The frameworks for the complicated interaction of these two hormones in the control of shoot apical meristem and root apical meristem formation as well as their roles in in vitro organ regeneration are the major focus of this review.


Subject(s)
Arabidopsis/metabolism , Cytokinins/metabolism , Indoleacetic Acids/metabolism , Meristem/growth & development , Plant Growth Regulators/metabolism , Arabidopsis/growth & development , Meristem/metabolism , Signal Transduction
18.
Mol Ther ; 17(6): 1109-15, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19352324

ABSTRACT

Despite the promise of proangiogenic gene therapy most clinical trials have failed to show benefit for the primary end point analysis. The NOGA angiogenesis Revascularization Therapy: assessment by RadioNuclide imaging (NORTHERN) trial was a double-blind, placebo-controlled study of intramyocardial vascular endothelial growth factor (VEGF165) gene therapy versus placebo, involving seven sites across Canada, designed to overcome major limitations of previous proangiogenic gene therapy trials. A total of 93 patients with refractory Canadian Cardiovascular Society (CCS) class 3 or 4 anginal symptoms were randomized to receive 2,000 microg of VEGF plasmid DNA or placebo (buffered saline) delivered via the endocardial route using an electroanatomical NOGA guidance catheter. There was no difference between the VEGF-treated and the placebo groups in the primary end point of change in myocardial perfusion from baseline to 3 or 6 months, assessed by single photon emission tomography (SPECT) imaging, although a significant reduction in the ischemic area was seen in both groups. Also, similar improvements in exercise treadmill time and anginal symptoms were seen in the VEGF and the placebo groups at 3 and 6 months, although again there were no differences between these groups. Despite the intramyocardial administration of a high "dose" of plasmid DNA using a percutaneous guidance catheter system, there was no benefit of VEGF gene therapy at 3 or 6 months for any of the end points studied.


Subject(s)
Coronary Disease/pathology , Coronary Disease/therapy , Genetic Therapy/methods , Vascular Endothelial Growth Factor A/physiology , Aged , Enzyme-Linked Immunosorbent Assay , Humans , Middle Aged , Myocardial Perfusion Imaging , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism
19.
J Crit Care ; 23(1): 82-90, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18359425

ABSTRACT

PURPOSE: The aim of this study was to determine the safety of targeted antibiotic therapy (TT) in ventilator-associated pneumonia (VAP). MATERIALS AND METHODS: This was a secondary analysis from a multicenter trial of 740 patients with suspected VAP randomized to bronchoscopy or endotracheal aspirate cultures; all received empirical broad-spectrum antibiotics. Patients were grouped by whether they received TT, defined as tailoring or discontinuing antibiotics in response to enrolment culture results. RESULTS: For patients with a positive culture (n = 412), baseline demographics, clinical progression of infection and multiple organ dysfunction scores (MODS), and mortality were similar for those on TT (n = 320) or those who did not receive TT (NoTT) (n = 92). The TT group had more days alive and off broad-spectrum antibiotics (14.5 vs 13.2, P = .04). In patients with a negative culture (n = 327), those on TT (n = 230) had similar baseline demographics, less frequent final adjudicated diagnosis of VAP (63.0% vs 76.3%, P = .02), and less severe clinical progression of infection and MODS compared with NoTT (n = 97). The TT group had more days alive and off broad-spectrum antibiotics (15.9 vs 13.1, P < .001), lower delta MODS (2.0 vs 3.0, P = .01), fewer mechanical ventilation days (9.8 vs 14.7, P = .03), and similar mortality compared to NoTT. CONCLUSIONS: Targeted therapy is associated with less antibiotic use and no evidence of harm in the management of patients with VAP.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Pneumonia, Ventilator-Associated/drug therapy , Bronchoalveolar Lavage Fluid/microbiology , Bronchoscopy , Canada , Chi-Square Distribution , Female , Humans , Intensive Care Units , Male , Middle Aged , Pneumonia, Ventilator-Associated/microbiology , Sputum/microbiology , Statistics, Nonparametric , Suction , Treatment Outcome , United States
20.
Nephrol Dial Transplant ; 23(7): 2299-303, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18281722

ABSTRACT

BACKGROUND: Our centre uses a modification of the Moncrief technique of embedding peritoneal dialysis (PD) catheters. We undertook this study to test the hypothesis that catheter survival on PD is a function of the time a catheter is left embedded prior to use. METHODS: Data were retrospectively abstracted from review of patient records of those who received a first PD catheter over a 5-year period. Patients were divided into tertiles based on the number of days between insertion of the catheter and exteriorization to create three equal groups representing early (group 1, 11-47 days), mid (group 2, 48-133 days) and late (group 3, 134-2041 days) exteriorization strategies. RESULTS: 435 embedded PD catheters were inserted, 349 were exteriorized and total observation period was 5624 patient-months. Time to catheter loss was shortest in group 1 and longest in group 2 (P = 0.04). The overall rate of primary catheter failure was 6% and was significantly different in the three groups (6.9% in group 1, 1.7% in group 2 and 9.4% in group 3, P = 0.04). The time to first episode of peritonitis was longest in group 3 and shortest in group 1 (group 1 versus group 3, P = 0.009; group 2 versus group 3, P = 0.03). Adjusted peritonitis rates, however, were not different between the three groups. CONCLUSIONS: Mechanical complications and catheter loss are associated with the length of time a catheter is embedded. We recommend insertion 6 weeks to 5 months ahead of the need for PD to maximize catheter survival.


Subject(s)
Catheters, Indwelling/adverse effects , Equipment Failure , Kidney Failure, Chronic/therapy , Peritoneal Dialysis/instrumentation , Peritonitis/epidemiology , Adult , Aged , Catheters, Indwelling/microbiology , Female , Humans , Incidence , Male , Middle Aged , Multivariate Analysis , Peritoneal Dialysis/methods , Peritonitis/microbiology , Retrospective Studies , Risk Factors , Time Factors
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