533 research outputs found
Eco-friendly facile synthesis of Co3O4-Pt nanorods for ethylene detection towards fruit quality monitoring
Ethylene, a biomarker widely employed for evaluating fruit ripening during storage, exists at extremely low concentrations. Therefore a gas sensor with high sensitivity and a sub-ppm detection limit is needed. In this work, porous Co3O4 nanorods were synthesized through a hydrothermal method involving Co(NO3)2, Na2C2O4, H2O and ethylene glycol (EG), followed by annealing at 400 degrees C in air. The surface of the porous Co3O4 nanorods was functionalized with Pt nanoparticles to enhance the ethylene sensing performance. The effect of Co3O4 surface functionalisation with Pt nanoparticles was investigated by adding different amounts of nanoparticles. The sensor's outstanding performance at the optimum working temperature of 250 degrees C is attributed to the synergy between the high catalytic activity of Pt nanoparticles and the extensive surface area of the porous Co3O4 nanorods. Compared to pure Co3O4, the 0.031 wt% Pt sensor showed better ethylene sensing performance with a response 3.4 times that of pristine Co3O4. The device also demonstrated high selectivity, repeatability, long-term stability and a detection limit of 0.13 ppm for ethylene, which is adequate for fruit quality monitoring. The gas sensing mechanism of porous Co3O4 nanorods and the influence of Pt decoration on sensor performance are discussed
Evaluation of the MODS Culture Technique for the Diagnosis of Tuberculous Meningitis
Tuberculous meningitis (TBM) is a devastating condition. The rapid instigation of appropraite chemotherapy is vital to reduce morbidity and mortality. However rapid diagnosis remains elusive; smear microscopy has extremely low sensitivity on cerebrospinal fluid (CSF) in most laboratories and PCR requires expertise with advanced infrastructure and has sensitivity of only around 60% under optimal conditions. Neither technique allows for the microbiological isolation of M. tuberculosis and subsequent drug susceptibility testing. We evaluated the recently developed microscopic observation drug susceptibility (MODS) assay format for speed and accuracy in diagnosing TBM.Two hundred and thirty consecutive CSF samples collected from 156 patients clinically suspected of TBM on presentation at a tertiary referal hospital in Vietnam were enrolled into the study over a five month period and tested by Ziehl-Neelsen (ZN) smear, MODS, Mycobacterial growth Indicator tube (MGIT) and Lowenstein-Jensen (LJ) culture. Sixty-one samples were from patients already on TB therapy for >1day and 19 samples were excluded due to untraceable patient records. One hundred and fifty samples from 137 newly presenting patients remained. Forty-two percent (n = 57/137) of patients were deemed to have TBM by clinical diagnostic and microbiological criteria (excluding MODS). Sensitivity by patient against clinical gold standard for ZN smear, MODS MGIT and LJ were 52.6%, 64.9%, 70.2% and 70.2%, respectively. Specificity of all microbiological techniques was 100%. Positive and negative predictive values for MODS were 100% and 78.7%, respectively for HIV infected patients and 100% and 82.1% for HIV negative patients. The median time to positive was 6 days (interquartile range 5-7), significantly faster than MGIT at 15.5 days (interquartile range 12-24), and LJ at 24 days (interquartile range 18-35 days) (P<0.01).We have shown MODS to be a sensitive, rapid technique for the diagnosis of TBM with high sensitivity, ease of performance and low cost (0.53 USD/sample)
Community, Family, and Partner-Related Stigma Experienced by Pregnant and Postpartum Women with HIV in Ho Chi Minh City, Vietnam
Pregnant and postpartum women with HIV often face stigma and discrimination at home and in the community. In Vietnam, associations between HIV and the “social evils” of drug use and sex work contribute to stigmatization of people with HIV. We conducted a qualitative study to explore discrimination experienced by HIV-positive pregnant and postpartum women in Ho Chi Minh City at home and in the community. We conducted 20 in-depth interviews and two focus group discussions. Participants described managing disclosure of their HIV infection because of fear of stigma and discrimination, particularly to the wider community. In cases where their HIV status was disclosed, women experienced both discrimination and support. The findings highlight the need for targeted interventions to support pregnant and postpartum women with HIV, particularly during this period when they are connected to the healthcare system and more readily available for counseling
COX inhibitors and breast cancer
There is considerable evidence to suggest that prostaglandins play an important role in the development and growth of cancer. The enzyme cyclo-oxygenase (COX) catalyses the conversion of arachidonic acid to prostaglandins. In recent years, there has been interest in a possible role for COX inhibitors in the prevention and treatment of malignancy. Cyclo-oxygenase-2 (COX-2) is overexpressed in several epithelial tumours, including breast cancer. Preclinical evidence favours an antitumour role for COX inhibitors in breast cancer. However, the epidemiological evidence for an association is conflicting. Trials are being conducted to study the use of COX inhibitors alone and in combination with other agents in the chemoprevention of breast cancer, and in the neo-adjuvant, adjuvant, and metastatic treatment settings. In evaluating the potential use of these agents particularly in cancer chemoprophylaxis, the safety profile is as important as their efficacy. Concern over the cardiovascular safety of both selective and nonselective COX-inhibitors has recently been highlighted
Zebrafish Krüppel-Like Factor 4a Represses Intestinal Cell Proliferation and Promotes Differentiation of Intestinal Cell Lineages
BACKGROUND:Mouse krüppel-like factor 4 (Klf4) is a zinc finger-containing transcription factor required for terminal differentiation of goblet cells in the colon. However, studies using either Klf4(-/-) mice or mice with conditionally deleted Klf4 in their gastric epithelia showed different results in the role of Klf4 in epithelial cell proliferation. We used zebrafish as a model organism to gain further understanding of the role of Klf4 in the intestinal cell proliferation and differentiation. METHODOLOGY/PRINCIPAL FINDINGS:We characterized the function of klf4a, a mammalian klf4 homologue by antisense morpholino oligomer knockdown. Zebrafish Klf4a shared high amino acid similarities with human and mouse Klf4. Phylogenetic analysis grouped zebrafish Klf4a together with both human and mouse Klf4 in a branch with high bootstrap value. In zebrafish, we demonstrate that Klf4a represses intestinal cell proliferation based on results of BrdU incorporation, p-Histone 3 immunostaining, and transmission electron microscopy analyses. Decreased PepT1 expression was detected in intestinal bulbs of 80- and 102-hours post fertilization (hpf) klf4a morphants. Significant reduction of alcian blue-stained goblet cell number was identified in intestines of 102- and 120-hpf klf4a morphants. Embryos treated with γ-secretase inhibitor showed increased klf4a expression in the intestine, while decreased klf4a expression and reduction in goblet cell number were observed in embryos injected with Notch intracellular domain (NICD) mRNA. We were able to detect recovery of goblet cell number in 102-hpf embryos that had been co-injected with both klf4a and Notch 1a NICD mRNA. CONCLUSIONS/SIGNIFICANCE:This study provides in vivo evidence showing that zebrafih Klf4a is essential for the repression of intestinal cell proliferation. Zebrafish Klf4a is required for the differentiation of goblet cells and the terminal differentiation of enterocytes. Moreover, the regulation of differentiation of goblet cells in zebrafish intestine by Notch signaling at least partially mediated through Klf4a
Myc regulates programmed cell death and radial glia dedifferentiation after neural injury in an echinoderm
Repeated cycles of Clostridium-directed enzyme prodrug therapy result in sustained antitumour effects in vivo
The unique properties of the tumour microenvironment can be exploited by using recombinant anaerobic clostridial spores as highly selective gene delivery vectors. Although several recombinant Clostridium species have been generated during the past decade, their efficacy has been limited. Our goal was to substantially improve the prospects of clostridia as a gene delivery vector. Therefore, we have assessed a series of nitroreductase (NTR) enzymes for their capacity to convert the innocuous CB1954 prodrug to its toxic derivative. Among the enzymes tested, one showed superior prodrug turnover characteristics. In addition, we established an efficient gene transfer procedure, based on conjugation, which allows for the first time genetic engineering of Clostridium strains with superior tumour colonisation properties with high success rates. This conjugation procedure was subsequently used to create a recombinant C. sporogenes overexpressing the isolated NTR enzyme. Finally, analogous to a clinical setting situation, we have tested the effect of multiple consecutive treatment cycles, with antibiotic bacterial clearance between cycles. Importantly, this regimen demonstrated that intravenously administered spores of NTR-recombinant C. sporogenes produced significant antitumour efficacy when combined with prodrug administration
Endothelin 1 levels in relation to clinical presentation and outcome of Henoch Schonlein purpura
<p>Abstract</p> <p>Background</p> <p>Henoch Schonlein purpura (HSP) is a common vasculitis of small vessels whereas endothelin-1 (ET-1) is usually reported elevated in vasculities and systematic inflammation. The aim of the present study was to investigate whether ET-1 levels are correlated with the clinical presentation and the outcome of HSP.</p> <p>Methods</p> <p>The study sample consisted of thirty consecutive patients with HSP. An equal number of healthy patients of similar age and the same gender were served as controls. The patients' age range was 2–12.6 years with a mean ± SD = 6.3 ± 3 years. All patients had a physical examination with a renal, and an overall clinical score. Blood and urinary biochemistry, immunology investigation, a skin biopsy and ET-1 measurements in blood and urine samples were made at presentation, 1 month later and 1 year after the appearance of HSP. The controls underwent the same investigation with the exception of skin biopsy.</p> <p>Results</p> <p>ET-1 levels in plasma and urine did not differ between patients and controls at three distinct time points. Furthermore the ET-1 were not correlated with the clinical score and renal involvement was independent from the ET-1 measurements. However, the urinary ET-1 levels were a significant predictor of the duration of the acute phase of HSP (HR = 0.98, p = 0.032, CI0.96–0.99). The ET-1 levels did not correlate with the duration of renal involvement.</p> <p>Conclusion</p> <p>Urinary ET-1 levels are a useful marker for the duration of the acute phase of HSP but not for the length of renal involvement.</p
Serum Uric Acid Levels Are Associated with Polymorphism in the SAA1 Gene in Chinese Subjects
OBJECTIVE: Serum uric acid (SUA) is a cardiovascular risk marker associated with inflammation. The serum amyloid A protein (SAA) is an inflammatory factor and is associated with cardiovascular disease (CVD). However, the relationship between genetic polymorphisms of SAA and SUA levels has not been studied. The objective of this study was to investigate the association between SUA levels and SAA genetic polymorphisms. METHODS: All participants were selected from subjects participating in the Cardiovascular Risk Survey (CRS) study. The single nucleotide polymorphism (SNP) rs12218 of the SAA1 gene was genotyped by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The association of SUA levels with genotypes was assessed by using the general liner mode. RESULTS: The SNP rs12218 was associated with SUA levels by analyses of a dominate model (P = 0.002) and additive model (P = 0.005), and the difference remained significant after adjustment of sex, age, obesity, ethnicity, HDL-C, alcohol intake, smoking, and creatinine (P = 0.006 and P = 0.023, respectively). The TT genotype was associated with an increased SUA concentration of 39.34 mmol/L (95% confidence interval [CI], 3.61-75.06, P = 0.031) compared with the CC genotype, and the TT genotype was associated with an increased SUA concentration of 2.48 mmol/L (95% CI, 6.86-38.10; P = 0.005) compared with the CT genotype. CONCLUSIONS: The rs12218 SNP in the SAA1 gene was associated with SUA levels in Chinese subjects, indicating that carriers of the T allele of rs12218 have a high risk of hyperuricemia
In silico transcriptional regulation and functional analysis of dengue shock syndrome associated SNPs in PLCE1 and MICB genes
YesSingle nucleotide polymorphisms (SNPs) in PLCE1
and MICB genes increase risk for the development of dengue
shock syndrome (DSS). We used Bioinformatics tools to predict
alterations at the transcriptional and posttranslational levels
driven by PLCE1 and MICB SNPs associated with DSS.
Functional and phenotypic analysis conducted to determine
deleterious SNPs and impact of amino acid substitution on
the structure and function of proteins identified rs2274223
(H1619R) as deleterious to protein coding as it induces structural
change in the C2 domain of PLCε, with the mutant residue
more positively charged than the wild-type residue (RMSD
score, 1.75 Å).Moreover, rs2274223 condenses the chromatinrepressing
PLCε expression in DSS. Briefly, this study presents
the impact of a single nucleotide transition at SNPs associated
with DSS on differential protein binding patterns with PLCE1
and MICB genes and on protein structure modification and their
possible role in the pathogenesis of DSS
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