The influence of tobacco retailers on adolescent smoking: prevention and policy implications

BACKGROUND

Smoking rates are higher among adolescents in South Korea than among those in other Asian countries. Researchers have reported associations between the presence of licensed tobacco retailers and adolescent smoking rates. However, few researchers have examined the factors that influence adolescent smoking including those that are intrapersonal, interpersonal or related to the tobacco retailers' environment.

AIM

The purpose of this study was to describe factors related to the students, the licensed tobacco retailers and the schools and how those factors are associated with adolescent smoking outcomes such as tobacco marketing receptivity, lifetime smoking and current smoking.

METHODS

The survey data were gathered from 740 South Korean adolescents, and geographic data for 3488 licensed tobacco retailers were also used. Geographic Information Systems and multilevel modeling were used to describe the variables and determine the factors associated with smoking outcomes in the sample.

RESULTS

The factors that influenced receptivity to tobacco marketing included the presence of peers who smoke and the frequencies of licensed tobacco retailers passed on the way to school. The factors that influenced lifetime smoking included gender, perceived economic status, weekly income, the presence of siblings or peers who smoke and frequencies of licensed tobacco retailers passed on the way to school. The factors that influenced current smoking included gender, weekly income, and the presence of siblings or peers who smoke.

CONCLUSIONS

These factors will guide adolescent tobacco prevention programs and policies.

IMPLICATIONS FOR NURSING PRACTICE AND HEALTH POLICY

The study's implications for nursing practice and health policy are that school nurses and public health nurses need to be encouraged to use retailer-related factors in adolescent smoking-prevention programs. There is also a need for zoning and licensing regulations to restrict licensed tobacco retailers in areas that adolescents frequent, including schools.

Developing a Real-Time PCR Assay for Direct Identification and Quantification of Pratylenchus penetrans in Soil

The root-lesion nematode Pratylenchus penetrans is a major pathogen of potato worldwide. Yield losses may be exacerbated by interaction with the fungus Verticillium dahliae in the potato early dying disease complex. Accurate identification and quantification of P. penetrans prior to planting are essential for developing effective integrated pest control measures. However, distinction between P. penetrans and other Pratylenchus spp. based on morphology is a tedious task. A SYBR Green I-based qPCR assay was developed to discriminate, identify, and quantify P. penetrans in field soil. P. penetrans-specific qPCR primers were designed from the D2-D3 region of the 28S rDNA. The specificity of the assay was evaluated using eight isolates of P. penetrans populations and 31 isolates of other nematode species. A standard curve relating threshold cycle and log values of nematode number was generated from artificially infested soils. There was a high correlation between the P. penetrans numbers artificially added to soil or estimated from naturally infested field soils by conventional methods, and the numbers quantified using the qPCR assay. Grinding the field soil prior to DNA extraction improved P. penetrans detection from soil. The qPCR assay will not only be useful for differentiating P. penetrans from mixed populations of Pratylenchus spp., but also for efficient detection and quantification of P. penetrans from field soil. The assay requires no expertise in nematode taxonomy and morphology, and may serve as a useful diagnostic tool in research, diagnostic labs, and extension services for pest management.

CHIP/Stub1 regulates the Warburg effect by promoting degradation of PKM2 in ovarian carcinoma

Tumor cells preferentially adopt aerobic glycolysis for their energy supply, a phenomenon known as the Warburg effect. It remains a matter of debate as to how the Warburg effect is regulated during tumor progression. Here, we show that CHIP (carboxyl terminus of Hsc70-interacting protein), a U-box E3 ligase, suppresses tumor progression in ovarian carcinomas by inhibiting aerobic glycolysis. While CHIP is downregulated in ovarian carcinoma, induced expression of CHIP results in significant inhibition of the tumor growth examined by in vitro and in vivo experiments. Reciprocally, depletion of CHIP leads to promotion of tumor growth. By a SiLAD proteomics analysis, we identified pyruvate kinase isoenzyme M2 (PKM2), a critical regulator of glycolysis in tumors, as a target that CHIP mediated for degradation. Accordingly, we show that CHIP regulates PKM2 protein stability and thereafter the energy metabolic processes. Depletion or knockout of CHIP increased the glycolytic products in both tumor and mouse embryonic fibroblast cells. Simultaneously, we observed that CHIP expression inversely correlated with PKM2 levels in human ovarian carcinomas. This study reveals a mechanism that the Warburg effect is regulated by CHIP through its function as an E3 ligase, which mediates the degradation of PKM2 during tumor progression. Our findings shed new light into understanding of ovarian carcinomas and may provide a new therapeutic strategy for ovarian cancer.

Use of Chemical Flocculation and Nested PCR for Heterodera glycines Detection in DNA Extracts from Field Soils with Low Population Densities

The soybean cyst nematode (SCN) Heterodera glycines is a major pathogen of soybean worldwide. Distinction between SCN and other members of the H. schachtii sensu stricto group based on morphology is a tedious task. A molecular assay was developed to detect SCN in field soils with low population densities and to differentiate SCN from other species. Various numbers of SCN eggs or juveniles were inoculated into 10 g of sterilized soil from which soil DNA was extracted using the PowerSoil DNA Isolation Kit. A specific amplicon was amplified using published SCN-specific primers SCNF1/SCNR1. This primer set was evaluated for the first time to detect SCN directly in soil DNA extracts. The specificity of the primers was confirmed by testing 36 isolates of other nematode species. The PCR assay detected one SCN egg or juvenile added to 10 g of soil. The assay was validated using 35 field soil samples. Grinding the field soil coupled with PCR inhibitor removal by AlNH₄(SO₄)₂0.12H₂O treatment of soil DNA extracts followed by nested PCR enabled SCN detection as low as 12 SCN eggs/200 g soil. The PCR assay not only provides a sensitive method for SCN detection at low densities but also provides a discrimination method for SCN from other closely related nematodes.

Development of Real-Time and Conventional PCR Assays for Identifying Stubby Root Nematode Paratrichodorus allius

Paratrichodorus allius is an important pest on many crops, particularly on potato due to its ability to transmit Tobacco rattle virus causing corky ringspot disease on tubers. Detection and identification of P. allius are important for effective disease management. In this study, a rapid and reliable molecular diagnosis of this nematode targeting internal transcribed spacer ribosomal DNA was established. The specificity of the designed primers was evaluated using 29 nematode species and results showed that a single amplicon was produced from DNA of P. allius only. Detection sensitivity analysis indicated that a 9.6 × 10^-4 ng of DNA template could be detected by conventional PCR and 1.92 × 10^-4 ng of DNA by real-time PCR. The PCR assays amplified DNA of stubby root nematodes isolated from 18 soil samples in North Dakota and Minnesota, which were confirmed as P. allius by sequencing. Both conventional PCR and real-time PCR assays amplified target nematodes from complex nematode communities, supporting the success of this molecular diagnosis of P. allius. This is the first report of P. allius identification using the real-time PCR method and from nematode communities with other nematodes using conventional PCR. The new PCR assays provide rapid species identification and are suitable for use in diagnostic laboratories and detection of field infestations with P. allius.

First Report of the Spiral Nematode Helicotylenchus microlobus Infecting Soybean in North Dakota

Spiral nematodes (Helicotylenchus spp.) are common plant-parasitic nematodes in fields of many crops. In June 2015, two soil samples were collected from a soybean field in Richland County, ND. Nematodes were extracted from soil using the sugar centrifugal flotation method (Jenkins, 1964). Plant-parasitic nematodes were identified to genus based on morphological features and counted. Both samples contained spiral nematodes from 1,500 to 3,300 per kilogram of soil. In June and August 2016, 10 soil samples were collected from the same field. Nematodes were extracted, and nine of the samples had spiral nematodes ranging from 125 to 3,065 per kilogram of soil. One soil sample with 1,500 spiral nematodes per kilogram was used to inoculate two soybean cultivars Sheyenne and Barnes each in four replicates. After 15 wk of growth at 22°C in a greenhouse room, the population of spiral nematodes was found to have increased greatly. The final density was 9,300 ± 1,701 spiral nematodes per kilogram of soil for Sheyenne and 9,451 ± 2,751 for Barnes. The reproductive factor in Sheyenne and Barnes was 6.2 and 6.3, respectively, indicating that this spiral nematode infects and reproduces well on these two soybean cultivars. Infected soybean roots had small brown lesions on the surface. Individual spiral nematodes were handpicked and examined morphologically and molecularly for species identification. Morphological measurements of adult females (n = 15) included body length (mean = 708.5 μm, range = 600.0-812.0 μm), stylet (27.6, 26.0-29.0), body width (28.3, 25.0-33.0), lip region end to posterior end of pharyngeal glands (142.5, 130.0-152.0), anal body width (15.8, 14.0-17.5), tail length (20.3, 15.0-25.0), tail annules (11.6, 10.0-14.0), a (25.0, 21.4-27.1), b (5.0, 4.4-5.7), c (35.4, 30.2-41.7), c' (1.3, 1.0-1.6), and V (61.8%, 60.0-63.7). The spiral nematode was identified as Helicotylenchus microlobus according to morphological and morphometric characteristics (Subbotin et al., 2015). DNA was extracted from single nematodes (n = 8) using the Proteinase K method (Kumari and Subbotin, 2012). The internal transcribed spacer (ITS) region of rDNA was amplified with the primers rDNA2/rDNA1.58S (Cherry et al., 1997). The PCR products were then purified and sequenced. The consensus ITS rDNA sequence (accession no. KY271078, 822 bp) that was deposited into the GenBank shared 99% identity with two isolates of H. microlobus from California (KM506860.1 and KM506859.1) and one isolate of H. microlobus from Spain (KM506862.1) (Subbotin et al., 2015). It had only 91% sequence identity with seven isolates of H. pseudorobustus (KM506875.1, KM506880.1, KM506876.1, KM506874.1, KM506872.1, KM506879.1, and KM506878.1) from California, Switzerland, and New Zealand, a spiral nematode species very closely related to H. microlobus in morphology. The molecular tests confirmed the identity of this spiral nematode as H. microlobus. The H. microlobus nematode was reported as one of the most commonly observed spiral nematodes in soil samples in the state of Minnesota, and all 13 soybean cultivars tested except Hawkeye were rated as hosts (Taylor, 1960). To our knowledge, this is the first report of H. microlobus in North Dakota.

Specific Detection of the Root-Lesion Nematode Pratylenchus scribneri Using Conventional and Real-Time PCR

Pratylenchus scribneri is a plant-parasitic root-lesion nematode causing economic damage to various crops worldwide. Identifying root-lesion nematodes to species using traditional morphological methods is an arduous task requiring extensive training on nematode taxonomy and years of experience. Thus, molecular methods for P. scribneri detection and identification were developed. Conventional and real-time polymerase chain reaction (PCR) assays with new species-specific primers were used in this study, which exclusively amplified DNA of P. scribneri but not DNA from other Pratylenchus spp. or non-Pratylenchus spp. tested. Compared with conventional PCR that was able to detect an equivalent to 1/4 of the DNA of a single nematode, real-time PCR was more sensitive and could amplify an equivalent to 1/128 of the DNA of one nematode. Both conventional and real-time PCR assays successfully identified P. scribneri and distinguished it from P. penetrans and P. neglectus isolated from field samples collected from various locations in North Dakota and Minnesota. The Blast-search based on the sequence information confirmed the reliability of the PCR assays for species identification. This is the first report of P. scribneri identification using a real-time PCR assay. The developed PCR assays are suitable for use in diagnostic laboratories and detection of field infestations with this nematode species.

Quantification of Paratrichodorus allius in DNA extracted from soil using TaqMan Probe and SYBR Green real-time PCR assays

The ectoparasitic stubby root nematode,Paratrichodorus allius, transmits tobacco rattle virus, which causes corky ringspot disease resulting in significant economic losses in the potato industry. A diagnostic method for direct quantification ofP. alliusfrom soil DNA using TaqMan probe and SYBR Green real-time PCR assays was developed to assist the potato industry in management of this important vector. Specificity of primers/probe designed from the internal transcribed spacer of ribosomal DNA ofP. alliuswas demonstrated byin silicoanalysis and experimental PCR tests with no cross reactions using non-target nematode species and nematode communities. The SYBR Green method was more sensitive than the TaqMan probe method during detection using serial diluted DNA templates. Standard curves were generated from serial dilutions of DNA extracted from autoclaved soil with artificially inoculatedP. alliusindividuals and were validated by high correlations between the numbers of target nematodes quantified by the assays and added to the soil. Moreover, the numbers ofP. alliusdetermined by the real-time PCR assays and estimated by the microscopic method in 17 field soil samples presented positive correlation relationships (). Although the quantification using TaqMan probe overestimated the target nematodes compared to using SYBR Green in eight out of ten field soil samples, results of the two methods correlated well (). This is the first report ofP. alliusquantification from soil DNA extracts using real-time PCR, providing a rapid and sensitive diagnostic method obviating time-consuming manual nematode extraction from soil and microscopic identification and quantification.

Clinical characteristics and long-term outcome of acute kidney injury in patients with HBV-related acute-on-chronic liver failure

Acute kidney injury (AKI) is a common complication in patients with decompensated cirrhosis and is also an important cause for poor outcome. This study aimed at investigating the clinical characteristics and long-term prognosis of AKI in patients with hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF). A total of 1167 patients with HBV-related ACLF from January 2010 to January 2015 were enrolled and divided into two groups, AKI group (n=308) and non-AKI group (n=859). All patients were followed up to investigate clinical characteristics, long-term overall survival (OS) and risk factors. AKI occurrence was found to be 26.4% in patients with HBV-related ACLF. The patients in the AKI group and the non-AKI group had a 30-day OS of 44.8% and 70.3%, 90-day OS of 17.9% and 55.4%, and 1-year OS of 15.6% and 51.2%, respectively. Significant differences were observed in the 30-day, 90-day and 1-year OS among subgroups with different AKI stages. It was found that high WBC, neutrophil, ALT and MELD score were risk factors for 30-day mortality, whereas hepatic encephalopathy, high MELD score, mean arterial pressure and PLT were risk factors for 90-day mortality. Two criteria, the KDIGO and AKIN, showed parallel results in staging AKI in patients with HBV-related ACLF (κ=0.807, P<.001). AKI is closely associated with increased short-term mortality in Chinese HBV-related ACLF patients, particularly in those with infection and high MELD score. Both KDIGO and AKIN criteria can be used for staging AKI in patients with HBV-related ACLF.

Genome-wide association studies identify susceptibility loci affecting respiratory disease in Chinese Erhualian pigs under natural conditions

Prevalence of swine respiratory disease causes poor growth performance in and serious economic losses to the swine industry. In this study, a categorical trait of enzootic pneumonia-like (EPL) score representing the infection gradient of a respiratory disease, more likely enzootic pneumonia, was recorded in a herd of 332 Chinese Erhualian pigs. According to their EPL scores and the disease effect on weight gains, these pigs were grouped into controls (EPL score ≤ 1) and cases (EPL score > 1). The weight gain of the case group reduced significantly at days 180, 210, 240 and 300 as compared to the control group. The heritability of EPL score was estimated to be 0.24 based on the pedigree information using a linear mixed model. All 332 Erhualian pigs and their nine sire parents were genotyped with Illumina Porcine 60K SNP chips. Two genome-wide association studies were performed under a generalized linear mixed model and a case-control model respectively. In total, five loci surpassed the suggestive significance level (P = 2.98 × 10^-5 ) on chromosomes 2, 8, 12 and 14. CXCL6, CXCL8, KIT and CTBP2 were highlighted as candidate genes that might play important roles in determining resistance/susceptibility to swine EP-like respiratory disease. The findings advance understanding of the genetic basis of resistance/susceptibility to respiratory disease in pigs.

Keratin-associated protein 5-5 controls cytoskeletal function and cancer cell vascular invasion

Cancer cell vascular invasion is a crucial step in the malignant progression towards metastasis. Here we used a genome-wide RNAi screen with E0771 mammary cancer cells to uncover drivers of endothelial monolayer invasion. We identified keratin-associated protein 5-5 (Krtap5-5) as a candidate. Krtap5-5 belongs to a large protein family that is implicated in crosslinking keratin intermediate filaments during hair formation, yet these keratin-associated proteins have no reported role in cancer. Depletion of Krtap5-5 from cancer cells led to cell blebbing and a loss of keratins 14 and 18, in addition to the upregulation of vimentin intermediate filaments. This intermediate filament subtype switching induced dysregulation of the actin cytoskeleton and reduced the expression of hemidesmosomal α6/β4-integrins. We further demonstrate that knockdown of keratin 18 phenocopies the loss of Krtap5-5, suggesting that Krtap5-5 crosstalks with keratin 18 in E0771 cells. Disruption of the keratin cytoskeleton by perturbing Krtap5-5 function broadly altered the expression of cytoskeleton regulators and the localization of cell surface markers. Krtap5-5 depletion did not impact cell viability but reduced cell motility and extracellular matrix invasion, as well as extravasation of cancer cells into tissues in zebrafish and mice. We conclude that Krtap5-5 is a previously unknown regulator of cytoskeletal function in cancer cells that modulates motility and vascular invasion. Thus, in addition to its physiologic function, a keratin-associated protein can serve as a switch towards malignant progression.