Selective determination of an ovarian cancer biomarker at low concentrations with surface imprinted nanotube based chemosensor

In this study, an electrochemical chemosensor that utilizes a conductive polymer-based molecularly imprinted polymer (MIP) surface for rapid and reliable determination of CA125 was devised. A novel method has been applied to fabricate CA125 imprinted polypyrrole nanotubes (MI-PPy NT) via vapor deposition polymerization (VDP) as a recognition element for highly selective and sensitive determination of CA125. The chemosensor was prepared by immobilizing MI-PPy NT onto screen-printed gold electrodes (Au-SPE) and the performance of the sensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in terms of selectivity, sensitivity, linear dynamic concentration range (LDR) and limit of detection (LOD). The MI-PPy NT@Au-SPE sensor exhibited high sensitivity (68.57 μA per decade) to the CA125 concentration ranging from 0.1 U mL-1 to 100 U mL-1 at an LOD of 0.4 U mL-1 with a correlation coefficient of 0.9922. The developed chemosensors with their novel design combined with a facile fabrication method, prove to be promising as future state-of-the-art biosensors.

Nitric oxide and nitrite removal by partial denitrifying hollow-fiber membrane biofilm reactor coupled with nitrous oxide generation as energy recovery

Nitrogen oxide (NOx) emissions cause significant impacts on the environment and must therefore be controlled even more stringently. This requires the development of cost-effective removal strategies which simultaneously create value-added by-products or energy from the waste. This study aims to treat gaseous nitric oxide (NO) by hollow-fibre membrane biofilm reactor (HFMBfR) in the presence of nitrite (NO2-) and evaluate nitrous oxide (N₂O) emissions formed as an intermediate product during the denitrification process. Accumulated N₂O can be utilised in methane oxidation as an oxidant to produce energy. In the first stage of the study, the HFMBfR was operated by feeding only gaseous NO as the nitrogen source. During this period, the best performance was achieved with 92% NO removal efficiency (RE). In the second stage, both NO gas and NO2- were supplied to the system, and 91% NO and 99% NO2- reduction were achieved simultaneously with the maximum N₂O generation of 386 ± 31 ppm. Lower influent carbon to nitrogen (C/N) ratios, such as 4.5 and 2.0, and higher NO2--N loading rate of 158 mg N day^-1 favoured N₂O generation. An improved NO removal rate and N₂O accumulation were seen with the increasing amount of PO43- in the medium. The 16S rDNA sequencing analysis revealed that Alicycliphilus denitrificans and Pseudomonas putida were the dominant species. The study shows that an HFMBfR can be successfully used to eliminate both NO2- and gaseous NO and simultaneously generate N₂O by adjusting the system parameters such as C/N ratio, NO2- and PO43- loading.

The effect of urgent blood pressure lowering on left atrial mechanics in patients with hypertensive episode in emergency setting

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial (LA) dilatation and dysfunction are early manifestation of hypertension and represent end-organ damage. Hypertension is a well-known risk factor for atrial fibrillation. Long term effect of hypertension on the left ventricle and left atrium was well-studied before. In this study, we aimed to investigate the acute effect of urgent blood pressure reduction on the left atrial strain.

Methods

We prospectively enrolled 52 consecutive patients (age: 67.5 ± 8.9 years, 48.1% male) (Fig1) admitted to our emergency department with a hypertensive attack. All patients underwent baseline standard echocardiographic evaluation. 2D images from apical 4-chamber view were recorded for offline analysis. Reservoir (PALS) and contractile (PACS) left atrial strain measurements were performed by automated software using the onset of QRS as a reference point. Patients with systolic dysfunction, acute coronary syndrome and any rhythym other than sinus or with poor echogeneicity were excluded. All measurements were repeated after achieving target blood pressure reduction and analyzed.

Results

Urgent blood pressure reduction result in improvement in LA contractile strain (PACS) and LVEF and increase in heart rate and RV systolic function while LV dimensions, LA volumes and LAVI were decreased. There is a statistically significant negative moderate relationship between absolute change of DBP and absolute change of PALS (r=-0.423; p = 0.002). There is a statistically significant negative and weak correlation between the absolute change in SBP and the absolute change in PACS (r=-0.280; p = 0.044).

Conclusion

Assessment of LA strain by 2D speckle tracking echocardiography is easy to apply and noninasive method to quantify LA function even in emergency setting. This study showed that LA contractile strain (PACS) rather than LA reservoir strain (PALS) was significantly affected from LV end diastolic pressure. Abstract Figure 1  Abstract Figure 2

Thermodynamically designed target-specific DNA probe as an electrochemical hybridization biosensor

Applications of molecular techniques to elucidate identity or function using biomarkers still remain highly empirical and biosensors are no exception. In the present study, target-specific oligonucleotide probes for E. coli K12 were designed thermodynamically and applied in an electrochemical DNA biosensor setup. Biosensor was prepared by immobilization of a stem-loop structured probe, modified with a thiol functional group at its 5' end and a biotin molecule at its 3' end, on a gold electrode through self-assembly. Mercaptopropionic acid (MPA) was used to optimize the surface probe density of the electrode. Hybridization between the immobilized probe and the target DNA was detected via the electrochemical response of streptavidin-horseradish peroxidase in the presence of the substrate. The amperometric response showed a linear relationship with the target DNA concentration, ranging from 10 and 400 nM, with a correlation coefficient of 0.989. High selectivity and good repeatability of the biosensor showed that the thermodynamic approach to oligonucleotide probe design can be used in development of electrochemical DNA biosensors.

Broad spectrum antibacterial photodynamic and photothermal therapy achieved with indocyanine green loaded SPIONs under near infrared irradiation

Antimicrobial photodynamic therapy (aPDT) and antimicrobial photothermal therapy (aPTT) are promising local and effective alternative therapies for antibiotic resistant bacterial infections and biofilms.

Different patterns of hepatocellular carcinoma-related malign thrombosis in 18F-FDG PET/CT

Tumor thrombus is an intravascular malign tumor extension that may occur in various types of cancer. Hepatocellular carcinomas (HCC) are common causes of malign thrombus. The presence of a malign thrombus due to HCC has a dismal prognosis, which affects treatment choices. We present three cases of tumor thrombi due to advanced HCC detected by ¹⁸F-FDG PET/CT.

The Role of AcrAB-TolC Efflux Pumps on Quinolone Resistance of E. coli ST131

Escherichia coli ST131 is a cause for global concern because of its high multidrug resistance and several virulence factors. In this study, the contribution of acrAB-TolC efflux system of E. coli ST131 to fluoroquinolone resistance was evaluated. A total of nonrepetitive 111 ciprofloxacin-resistant E. coli isolates were included in the study. Multilocus sequence typing was used for genotyping. Expressions of acrA, acrB, and TolC efflux pump genes were measured by RT-PCR. Mutations in marA, gyrA, parC, and aac(6')-lb-cr positivity were studied by Sanger sequencing. Sixty-four (57.7%) of the isolates were classified as ST131, and 52 (81.3%) of the ST131 isolates belonged to H30-Rx subclone. In ST131, CTX-M 15 positivity (73%) and aac(6')-lb-cr carriage (75%) were significantly higher than those in non-ST131 (12.8% and 51%, respectively) (P < 0.05). The ampicillin-sulbactam (83%) resistance was higher, and gentamicin resistance (20%) was lower in ST131 than that in non-ST131 (64% and 55%, respectively) (P = 0.001 and P = 0.0002). Numbers of the isolates with MDR or XDR profiles did not differ in both groups. Multiple in-dels (up to 16) were recorded in all quinolone-resistant isolates. However, marA gene was more overexpressed in ST131 compared to that in non-ST131 (median 5.98 vs. 3.99; P = 0.0007). Belonging to H30-Rx subclone, isolation site, ciprofloxacin MIC values did not correlate with efflux pump expressions. In conclusion, the marA regulatory gene of AcrAB-TolC efflux pump system has a significant impact on quinolone resistance and progression to MDR profile in ST131 clone. Efflux pump inhibitors might be alternative drugs for the treatment of infections caused by E. coli ST131 if used synergistically in combination with antibiotics.

Rapid emergence of colistin resistance and its impact on fatality among healthcare-associated infections

This article describes the emergence of resistance and predictors of fatality for 1556 cases of healthcare-associated Gram-negative bloodstream infection in 2014 and 2015. The colistin resistance rate in Klebsiella pneumoniae was 16.1%, compared with 6% in 2013. In total, 660 (42.4%) cases were fatal. The highest fatality rate was among patients with Acinetobacter baumannii bacteraemia (58%), followed by Pseudomonas aeruginosa (45%), Klebsiella pneumoniae (41%), Enterobacter cloacae (32%) and Escherichia coli (28%). On multi-variate analysis, the minimum inhibitory concentrations for carbapenems [odds ratio (OR) 1.02, 95% confidence interval (CI) 1.01-1.04; P = 0.002] and colistin (OR 1.1, 95% CI 1.03-1.17; P = 0.001) were found to be significantly associated with fatality.

Study of the remarkable reactivity of HNCO/urea with NO2 in the NOx SCR by urea process over an oxide-based catalyst

An exceptional reactivity between NO₂ and the reductant species was demonstrated during NO₂-SCR experiments with urea, when only NO₂ was used as NO_x.

Healthcare-associated Gram-negative bloodstream infections: antibiotic resistance and predictors of mortality

This article describes the prevalence of antibiotic resistance and predictors of mortality for healthcare-associated (HA) Gram-negative bloodstream infections (GN-BSI). In total, 831 cases of HA GN-BSI from 17 intensive care units in different centres in Turkey were included; the all-cause mortality rate was 44%. Carbapenem resistance in Klebsiella pneumoniae was 38%, and the colistin resistance rate was 6%. Multi-variate analysis showed that age >70 years [odds ratio (OR) 2, 95% confidence interval (CI) 1.22-3.51], central venous catheter use (OR 2.1, 95% CI 1.09-4.07), ventilator-associated pneumonia (OR 1.9, 95% CI 1.1-3.16), carbapenem resistance (OR 1.8, 95% CI 1.11-2.95) and APACHE II score (OR 1.1, 95% CI 1.07-1.13) were significantly associated with mortality.

Primary extranodal non-Hodgkin's lymphoma presenting as painful gingival swelling

Primary extra-nodal non-Hodgkin's lymphomas (NHL) constitute 25-40% of NHL but less than 1% arises in oral cavity. Here in 53-year-old man with stage IE gingival diffuse large B cell lymphoma who was treated successfully with chemotherapy and radiotherapy was presented.

Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode

This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44-1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N=3) with a relative standard deviation (RSD) of 5.4% (n=7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 μg/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday.

Glucose oxidase-polypyrrole electrodes synthesized in p-toluenesulfonic acid and sodium p-toluenesulfonate

Amperometric glucose biosensors have been developed based on entrapment on platinum (Pt) electrode using cyclic voltammetry technique in glucose oxidase (GOD) and pyrrole containing p-toluenesulfonic acid (pTSA) or sodium p-toluenesulfonate (NapTS) as supporting electrolyte solutions. Both of electrolyte solutions were suitable media for the formation and deposition of polypyrrole-GOD (PPy-GOD) layers on Pt substrate. Pt/PPy-GOD electrodes brought about in different morphological properties as well as different electrochemical and biochemical response. The highest responses obtained in pTSA and NapTS electrolytes were observed at pH of 4.5 and 7.0 for Pt/PPy-GOD electrodes, respectively. While linearity was observed between 0.0-1.0 mM glucose substrate for both electrodes, I(max) value of Pt/PPy-GOD(NapTS) electrode was approximately twice as high as that of Pt/PPy-GOD(pTSA) electrode as 25.4 and 14.2 microA, respectively. Five commercial drinks were tested with enzyme electrodes and compared with results obtained spectrophotometrically using glucose kit. Results revealed that Pt/PPy-GOD(NapTS) electrode exhibited better biosensor response.

Determining in vitro synergistic activities of tigecycline with several other antibiotics against Brucella melitensis using checkerboard and time-kill assays

Antimicrobial therapy of Brucella spp. infection is difficult because there are relatively few effective treatment regimens, and single-agent therapy has generally been considered inadequate due to unacceptably high relapse rates. tigecycline, the first in a new class of antimicrobials, the glycylcyclines, is a 9-t-butylglycylamido derivate of minocycline. in this study, the in vitro activity of tigecycline in combination with gentamicin, streptomycin, rifampin, co-trimoxazole, levofloxacin, and minocycline was investigated using the checkerboard method to evaluate 16 Brucella melitensis isolates. The time-kill method was used to determine the bactericidal activities of combinations of tigecycline with rifampin, gentamicin, and levofloxacin, which were found (via the checkerboard method) to have a synergistic effect in combinations with tigecycline. Using the checkerboard method, combinations of rifampin, gentamicin, and levofloxacin with tigecycline showed synergistic effects against 5 (31.2%), 3 (18.9%), and 8 (50%) of the isolates. No synergy was observed with tigecycline in combination with minocycline, streptomycin, or co-trimoxazole. tigecycline with gentamicin achieved the earliest complete killing at 4x miC (in 6 h), while complete killing with the other combinations was delayed up to 24 h. the time-kill method showed that the combination of tigecycline and levofloxacin had an antagonistic effect, while the checkerboard method detected synergy and no interaction effects. these data suggest that a combination regimen of tigecycline with gentamicin and rifampin may be a good choice for treating brucellosis.

In vitro antifungal susceptibility patterns of dermatophyte strains causing tinea unguium

BACKGROUND

Dermatophytes are the major responsible organisms in onychomycosis. Although recent antifungal agents have high success rates in treating this condition, lack of clinical response may occur in 20%. Antifungal drug resistance may be one of the causes of treatment failure. The need for in vitro antifungal drug resistance in daily practice is still under discussion.

OBJECTIVE

We aimed to determine the in vitro susceptibility patterns of dermatophytes causing onychomycosis, against the traditionally available systemic antifungal agents terbinafine, itraconazole and fluconazole.

METHODS

In total, 100 otherwise healthy patients with suspected onychomycosis were included. Nail clippings were cultured on Sabouraud dexrose agar, mycobiotic agar and dermatophyte test medium. Antifungal susceptibility tests were carried out, mainly following The National Committee for Clinical and Laboratory Standards (M38-P) protocol standard for filamentous fungi. Different concentrations of terbinafine (0.008-8 microg/mL), itraconazole (0.015-16 microg/mL) and fluconazole (0.06-64 microg/mL) were tested. Minimum inhibitory concentration end-point determination was chosen as 100% growth inhibition for terbinafine and 80% for azoles.

RESULTS

Of the 100 nail samples, 43% grew dermatophytes. The main causative organism was Trichophyton rubrum (91%) followed by Trichophyton mentagrophytes (9%). Terbinafine had the lowest minimum inhibitory concentration (0.008 microg/mL) followed by itraconazole. Fluconazole showed the greatest variation in minimum inhibitory concentration (0.03-2 microg/mL) and had different susceptibility patterns for the two species.

CONCLUSIONS

Of the three antifungals tested, terbinafine had the most potent in vitro antifungal activity against dermatophytes. Antifungal susceptibility tests would be useful to screen antifungal-resistant dermatophyte strains.

Apoptosis and proliferation in gastric epithelium due to Helicobacter pylori: an immunohistochemical and ultrastructural study

The effect of H. pylori infection on gastric epithelial cell apoptosis and proliferation is contradictory. Using immunohistochemistry and electron microscopy, this study sought to demonstrate gastric epithelial changes (ie, apoptosis and proliferation) due to chronic H. pylori infection.

METHODS

Eighteen female 6- to 8-week old Swiss Albino mice were inoculated intragastrically with 3 doses of 10(9) CFU/mL H. pylori prepared in a Brucella Broth in 5 days. Nine others served as a control group. At the end of 28 weeks, tissue specimens from the gastric antrum were excised and examined immunohistochemically (epithelial growth factor for regeneration and Caspase-3 for apoptosis) and electron microscopically. Immunohistochemical assessment was performed using the indirect peroxidase-antiperoxidase method.

RESULTS

In the H. pylori-infected group, EGF staining in gastric epithelium was found to be decreased significantly compared to that in control group (P < 0.001). Caspase-3 reactivity was commonly observed in surface epithelial cells and glandular epithelial cells in H. pylori-infected group and totally it was statistically significant compared to Caspase-3 staining in control group (P < 0.001). Electron micrograph images demonstrated numerous apoptotic cells with condensed chromatin.

CONCLUSION

Chronic H. pylori infection of 28 weeks' duration increases apoptosis in gastric epithelium; however, increased apoptosis does not induce proliferation.

Control of Yellowmargined Leaf Beetle on Turnip, 1995

Insecticide treatments were applied at labeled rates on 11 May and 18 May at the Burden Research Plantation, Baton Rouge, LA, 1995 on turnip. A CO2 powered backpack sprayer calibrated to deliver 40 gallons per acre at 30 psi through a spray boom with three nozzles was used. Experimental plots consisted of single rows (30 ft long, 4 ft wide) arranged in a RCB design with 4 replications. Insect counts were made with beat sheets (3 X 2) on 10 and 17 May (pre-treatment counts) and 12 and 19 May (post-treatment counts). Three samples were taken from each plot and the number of insects present of each species was recorded.