Quantification of in-vitro post-antibiotic effect based on the mean recovery-time. II: A comparison of colony counting versus photometric methods for the determination of bacterial growth

1991 ◽  
Vol 28 (4) ◽  
pp. 515-521 ◽  
Author(s):  
Xu Meng ◽  
Charles H. Nightingale ◽  
Kevin R. Sweeney
Keyword(s):  
Bacterial Growth ◽  
Recovery Time ◽  
Antibiotic Effect ◽  
Colony Counting ◽  
The Mean ◽  
Post Antibiotic Effect

High-resolution capillary electrophoresis for the determination of carbamylated albumin

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Julien Favresse ◽  
Joris Delanghe
Keyword(s):  
Separation Efficiency ◽  
Theoretical Plate ◽  
Clinical Routine ◽  
Negative Prognostic Factor ◽  
Symmetry Factor ◽  
Primary Amino ◽  
The Mean ◽  
Dose Dependent

Abstract Objectives Carbamylation is a non-enzymatic post-translational reaction of a primary amino group of a protein with isocyanate. The albumin carbamylation is a negative prognostic factor in chronic kidney disease (CKD) patients and induce charge difference implying an observed shift in electrophoretic mobility that can be measured through a symmetry factor (SF). Methods The Helena V8 and the Sebia Capillarys 2 systems were used for all experiments. The effect of in vitro carbamylation on the SF by spiking increasing concentrations of potassium isocyanate (KCNO) in serum of three healthy volunteers was investigated. Theoretical plate numbers (N) as a surrogate of separation efficiency were also calculated and correlations between SF and renal function biomarkers were performed on 284 patients. Results A dose-dependent impact of KCNO on the SF was observed for both methods with the Helena V8 being more sensitive. The mean N was significantly higher on the Helena V8 as compared to the Sebia Capillarys 2 (2,972 vs. 444.1, p<0.0001). The SF correlated significantly with eGFR (r=0.50, p<0.0001), creatinine (r=−0.31, p<0.0001) and urea (r=−0.34, p<0.0001) on the Helena V8. On the Sebia Capillarys 2, a significant correlation was only observed with eGFR (r=0.17, p=0.004). A better discrimination between CKD stages was also observed using the Helena V8. Conclusions Thanks to a higher mean N, the Helena V8 might offer new possibilities, including detection of carbamylated albumin through SF calculation. Further studies are still needed to confirm the interest of using this type of assays in clinical routine.

scholarly journals Post-antibiotic effect of marbofloxacin, enrofloxacin and amoxicillin against selected respiratory pathogens of pigs

2019 ◽  
Vol 64 (No. 02) ◽  
pp. 67-77 ◽  
Author(s):  
K Nedbalcova ◽  
M Zouharova ◽  
D Sperling
Keyword(s):  
Bacterial Infections ◽  
Pasteurella Multocida ◽  
Clinical Samples ◽  
Respiratory Pathogens ◽  
Minimal Inhibitory Concentrations ◽  
Antibiotic Effect ◽  
Significant Difference ◽  
Effect Duration ◽  
Post Antibiotic Effect

The post-antibiotic effect is defined as the period of bacterial growth suppression that persists after a limited exposure of organisms to antimicrobials and knowledge of its duration is important in establishing and optimising current dosing schedules for the treatment of bacterial infections. The post-antibiotic effect of marbofloxacin, enrofloxacin and amoxicillin were evaluated in vitro for Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida strains which originated from clinical samples of diseased pigs and were confirmed as susceptible to all tested antimicrobials based on determination of minimal inhibitory concentrations. The post-antibiotic effect for individual antimicrobials was monitored at five and ten times minimum inhibitory concentrations for one and two hours. The duration of the post-antibiotic effect for tested antimicrobials was found to exhibit the following order for all tested pathogens: marbofloxacin &gt; enrofloxacin &gt; amoxicillin. The longest duration of post-antibiotic effect of all tested antimicrobials was found in A. pleuropneumoniae and the shortest post-antibiotic effect duration was detected in P. multocida. No statistical differences in post-antibiotic effect duration were found within marbofloxacin and enrofloxacin in A. pleuropneumoniae and H. parasuis strains. In P. multocida strains there was a statistically significant difference (P = 0.0189). On the other hand, the differences between amoxicillin and marbofloxacin or enrofloxacin were statistically significant in all cases (P-values ranged between 0.0058 and 0.008). The prolonged post-antibiotic effect of fluoroquinolones and amoxicillin on important Gram-negative swine pathogens was confirmed. The results can be used to clarify the effect and mechanism of action of antimicrobial drugs in veterinary medicine.

scholarly journals Determination of Diclofenac Sodium in Eagle's Minimum Essential Medium with Earle's Balanced Salt Solution

2003 ◽  
Vol 86 (4) ◽  
pp. 681-684
Author(s):  
Patrícia S Lopes ◽  
Telma M Kaneko ◽  
Carolina Y Takano ◽  
Aurea C L Lacerda ◽  
Leandro R Latorre ◽  
...  
Keyword(s):  
Salt Solution ◽  
Diclofenac Sodium ◽  
Reversed Phase ◽  
Minimum Essential Medium ◽  
In Vitro Permeation ◽  
Hydrophilic Drug ◽  
Permeation Studies ◽  
The Mean

Abstract A validated method was developed for determination of diclofenac sodium, considered a model hydrophilic drug for in vitro permeation studies, in Eagle's Minimum Essential Medium (MEM) with Earle's balanced salt solution. Liquid chromatography was used to determine diclofenac sodium. This method was developed with a reversed-phase column Supercosil LC 18, DB 25 cm × 4.5 mm; the mobile phase was methanol with 3% (v/v) acetic acid–Milli-Q water (74 + 26), and detection was at 283 nm. The detection and quantitation limits were 2.41 × 10–8 and 3.31 × 10–5 μg/μL, respectively. The accuracy within-day (n = 3) and day-to-day (n = 7) was 98.83%; the mean variation coefficient for inter- (n = 7) and intraday precision (n = 3) was 12.20%, thus, not exceeding 15%. This method can be used as an analytical procedure for the determination of diclofenac sodium in MEM for in vitro permeation studies.

scholarly journals Effect of mupirocin in Helicobacter pylori in vitro

2021 ◽  
Vol 8 (1) ◽  
pp. 160-165
Author(s):  
Masaaki Minami ◽  
Takafumi Ando ◽  
Hidemi Goto ◽  
Michio Ohta
Keyword(s):  
Helicobacter Pylori ◽  
Bactericidal Effect ◽  
Dependent Manner ◽  
Antibiotic Effect ◽  
Resistant Strains ◽  
Kill Curve ◽  
H Pylori ◽  
Time Kill ◽  
Post Antibiotic Effect

Mupirocin (MUP) is an effective antibiotic against MRSA. Its bactericidal effect is stable under acid condition. By validating its antibacterial effect of Helicobacter pylori, we try to clarify MUP effect on H. pylori. The present study was conducted to investigate the effect of MUP on clarithromycin (CLR) / metronidazole (MNZ) -resistant and -susceptible strains of H. pylori, the time-kill effect of MUP, and the post antibiotic effect (PAE). We investigated the minimal inhibitory concentration (MIC) and the minimal bactericidal effect (MBC) of MUP against 140 H. pylori, which include clinical strains, ATCC43504, 26695 and J99. Ten of them were CLR -resistant strains and 3 were MNZ-resistant strains. The MIC90 and MBC of MUP on all 140 strains is 0.064 μg / ml, and 0.1 μg / ml, respectively. There were no differences of MUP effect between susceptible and resistant strains either for CLR or MNZ. Time-kill curve test and PAE test of MUP on ATCC43504 were performed. By adding MUP, time-kill curve showed that bacterial quantities decreased in dose and time-dependent manner. No viable colony was found after 12-hour culture with 0.1 μg / ml MUP. The value of PAE is 12. MUP is a potential effective antibiotic for H. pylori even those for CLR / MNZ -resistant strains.

Optimized steps in fluorometric determination of thiobarbituric acid-reactive substances in serum: importance of extraction pH and influence of sample preservation and storage

1993 ◽  
Vol 39 (12) ◽  
pp. 2522-2526 ◽  
Author(s):  
W Wasowicz ◽  
J Nève ◽  
A Peretz
Keyword(s):  
Thiobarbituric Acid ◽  
Thiobarbituric Acid Reactive Substances ◽  
Fluorometric Method ◽  
C Storage ◽  
Insulin Dependent ◽  
The Mean ◽  
Optimized Conditions ◽  
And Storage

Abstract A simple, reliable, and reproducible fluorometric method for measuring thiobarbituric acid-reactive substances (TBARS) in serum is proposed, based on the reaction between malondialdehyde (MDA) and thiobarbituric acid. Formation of TBARS was complete at pH 2.4-2.6, but extraction with n-butanol proved complete only at lower pH, i.e., 1.6-1.7. Analytical recoveries of MDA added to serum were 94%-101%; within- and between-run CVs were 2.4-3.6% and 4.6-5.5%; and the detection limit for TBARS in serum was 0.10 mumol/L. Optimized conditions included: (a) collection of either serum or heparinized plasma, (b) preservation from in vitro autoxidation by glutathione and EDTA, and (c) storage at -20 degrees C up to 35 days. The mean (+/- SD) TBARS concentration in 47 healthy adults was 1.01 (0.21) mumol/L; no sex-related difference was observed. Higher concentrations were measured in patients with renal insufficiency undergoing hemodialysis and in patients with insulin-dependent diabetes, chronic pancreatitis, or liver cirrhosis.

Evaluation of Potential Analytical Approach for Determination of Polychlorinated Biphenyls in Serum: Interlaboratory Study

1983 ◽  
Vol 66 (4) ◽  
pp. 956-968
Author(s):  
Virlyn W Burse ◽  
Larry L Needham ◽  
Chester R Lapeza ◽  
Margaret P Korver ◽  
John A Liddle ◽  
...  
Keyword(s):  
Polychlorinated Biphenyls ◽  
Ethyl Ether ◽  
Analytical Approach ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Coefficients Of Variation ◽  
The Mean

Abstract Forty-four laboratories participated in evaluation of a method for determining polychlorinated biphenyls (PCBs) as AR 1254 in serum at the parts per billion level. The method involves deproteinating serum with methanol, extracting with hexane-ethyl ether, and eluting PCBs from deactivated silica gel for gasliquid chromatographic determination with electron capture detection. Compounds are quantitated by using the Webb-McCall factors. Five serum pools, 4 containing in vivo-fortified PCBs (as AR 1254) or 8 in vitro-f ortif ied chlorinated hydrocarbons (CHs), or both, were used. For PCB fortification levels of 9.89 (EP 2), 24.74 (EP 3), and 74.20 ppb (EP 4), interlaboratory coefficients of variation (CVs) for collaborators that adhered to protocol were 92.7, 67.6, and 25.8%, respectively. CVs on the same pools analyzed by the Centers for Disease Control (CDC) were 7.4, 7.8, and 4.6%, respectively. Average interlaboratory recoveries for pools EP 2, EP 3, and EP 4 were 138.1,111.2, and 91.1%, respectively, and 99.8,89.6, and 90.4%, respectively, for CDC on the same pools. There was a general decrease in the mean error for those laboratories that had participated in an earlier study in which they were allowed to use their own methods.

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