scholarly journals Studies on the Stability of Drugs in Biological Media. IV. Disappearance of Nitrofurans in Culture Media inoculated with Staphylococci

1972 ◽  
Vol 20 (6) ◽  
pp. 1131-1138
Author(s):  
KIKUO IWAMOTO ◽  
KOICHIRO ODA ◽  
SHOZO MURANISHI ◽  
HITOSHI SEZAKI ◽  
KIICHIRO KAKEMI
1968 ◽  
Vol 16 (8) ◽  
pp. 1481-1486 ◽  
Author(s):  
KIICHIRO KAKEMI ◽  
HITOSHI SEZAKI ◽  
NORIO TAKASUGI ◽  
KIKUO IWAMOTO

2012 ◽  
Vol 610-613 ◽  
pp. 215-219
Author(s):  
Yun Xiao He ◽  
Xiao Ming Chen

The stability factors for Cr6+ and Cr3+ in microbiological media, including temperature, preservation conditions and medium components were studied in this research project, through potassium permanganate oxidation and DPC (Diphenylcarbazide) spectrophotometry. It shows that the protein component mainly influences Cr6+ content changes at pre- and post- heat sterilization to the chromium ionic liquid medium, other than being impacted basically by inorganic salt ions. It also indicates that the method can be introduced into experiment researches for microbe dechromisation i.e. Chromium ion aqueous solution and fluid medium are sterilized separately, and then are made into the chrome ions liquid as per a certain concentration. The concentration of hexavalent chromium ions is affected by preservation time and temperature also. For this reason, chromium ionic liquid medium is kept at low temperature, and as quickly as possible for the test.


Author(s):  
Mohd Amin Marwan Mohamad ◽  
Muhammad Alif Mazlan ◽  
Muhammad Ibrahim ◽  
Afzan Mat Yusof ◽  
Shamsul Azlin Ahmad Shamsuddin ◽  
...  

Stem cells provide various potential applications in regenerative medicine through its ability of self-renewal and differentiation. Among the various stem cells, dental pulp stem cells (DPSCs) have shown encouraging results in their ability to regenerate. Honey has been used in traditional culture as a natural medicine in supporting wound healing. Yet, very few studies on honey were conducted for its potential as a proliferative agent for stem cells. The aim of this study is to evaluate the stability of two Trigona spp. honeys (1 and 2) added in culture media and its proliferative effect on DPSCs. Both honeys were diluted with standard culture medium through dilution process to prepare the concentrations of 0.01%, 0.04%, 0.10% and 0.25%. DPSCs were treated with the diluted honeys for 24 hours. The proliferative activity was determined through the images taken using an inverted microscope for every six hours. In addition, the MTT assay was conducted to determine the cell viability of DPSCs when treated with both honey 1 and 2 at various concentrations. The results showed a stable culture media added with honey for three days and a dose-dependent proliferative effect of both Trigona spp. honey samples on DPSCs. Optimum proliferative effects were observed at 24 hours for both Trigona spp. honey 1 and 2 on DPSCs. The optimum concentration of Trigona spp. honey 1 was from 0.04% to 0.10% and Trigona spp. honey 2 was below 0.01%. It is concluded that Trigona spp. honey has a promising proliferative effect on DPSCs.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Mark Taylor ◽  
Simone Santopietro ◽  
Andrew Baxter ◽  
Nicole East ◽  
Damien Breheny ◽  
...  

Abstract Objectives Cigarette smoke aqueous aerosol extracts (AqE) have been used for assessing tobacco products, particularly with in vitro models such as oxidative stress and inflammation. These test articles can be generated easily, but there are no standardised methods for the generation and characterisation or stability. We investigated the effects of pro-oxidant smoke-derived chemicals by using 3R4F AqE generated under standardised conditioning and smoking regimes and assessed the stability over 31-week timeframe. Twenty batches generated from ten puffs per cigarette bubbled through 20 ml cell culture media were used fresh and thawed from frozen aliquots stored at – 80 ºC. Results Nicotine levels quantified by gas chromatography/mass spectrometry and optical density at 260 nm showed chemical and physical stability from week 0 (fresh sample) to weeks 1, 4, 8 and 31 (frozen samples). No significant change in H292 human bronchial epithelial cell viability or oxidative stress were observed between fresh AqE at week 0 and frozen AqE at 31 weeks. AqEs generated by our protocol were stable for up to 31 weeks for all tested end points, suggesting that it may not be necessary to use freshly generated AqE for each study, thus reducing batch-to-batch variability.


2020 ◽  
Author(s):  
Sandra Westhaus ◽  
Marek Widera ◽  
Holger F. Rabenau ◽  
Sebastian Hoehl ◽  
Denisa Bojkova ◽  
...  

SummaryThe novel coronavirus SARS-CoV-2 is the causative agent of the acute respiratory disease COVID-19, which has become a global concern due to its rapid spread. Laboratory work with SARS-CoV-2 in a laboratory setting was rated to biosafety level 3 (BSL-3) biocontainment level. However, certain research applications in particular in molecular biology require incomplete denaturation of the proteins, which might cause safety issues handling contaminated samples. In particular, it is critical to provide proof of inactivation before samples can be removed from the BSL-3.In this study, the stability of the virus in cell culture media at 4°C and on touch panel surfaces used in laboratory environment was analyzed. In addition, we evaluated common lysis buffers that are used in molecular biological laboratories for their ability to inactivate SARS-CoV-2. We have found that guanidine thiocyanate and most of the tested detergent containing lysis buffers were effective in inactivation of SARS-CoV-2, however, the M-PER lysis buffer containing a proprietary detergent failed to inactivate SARS-CoV-2. Furthermore, we compared chemical and non-chemical inactivation methods including ethanol, acetone-methanol mixture, PFA, UV-C light, and heat inactivation.In conclusion, careful evaluation of the used inactivation methods are required and additional inactivation steps are necessary before removal of lysed viral samples from BSL-3.


mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Jennifer Biryukov ◽  
Jeremy A. Boydston ◽  
Rebecca A. Dunning ◽  
John J. Yeager ◽  
Stewart Wood ◽  
...  

ABSTRACT Coronavirus disease 2019 (COVID-19) was first identified in China in late 2019 and is caused by newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Previous studies had reported the stability of SARS-CoV-2 in cell culture media and deposited onto surfaces under a limited set of environmental conditions. Here, we broadly investigated the effects of relative humidity, temperature, and droplet size on the stability of SARS-CoV-2 in a simulated clinically relevant matrix dried on nonporous surfaces. The results show that SARS-CoV-2 decayed more rapidly when either humidity or temperature was increased but that droplet volume (1 to 50 μl) and surface type (stainless steel, plastic, or nitrile glove) did not significantly impact decay rate. At room temperature (24°C), virus half-life ranged from 6.3 to 18.6 h depending on the relative humidity but was reduced to 1.0 to 8.9 h when the temperature was increased to 35°C. These findings suggest that a potential for fomite transmission may persist for hours to days in indoor environments and have implications for assessment of the risk posed by surface contamination in indoor environments. IMPORTANCE Mitigating the transmission of SARS-CoV-2 in clinical settings and public spaces is critically important to reduce the number of COVID-19 cases while effective vaccines and therapeutics are under development. SARS-CoV-2 transmission is thought to primarily occur through direct person-to-person transfer of infectious respiratory droplets or through aerosol-generating medical procedures. However, contact with contaminated surfaces may also play a significant role. In this context, understanding the factors contributing to SARS-CoV-2 persistence on surfaces will enable a more accurate estimation of the risk of contact transmission and inform mitigation strategies. To this end, we have developed a simple mathematical model that can be used to estimate virus decay on nonporous surfaces under a range of conditions and which may be utilized operationally to identify indoor environments in which the virus is most persistent.


2020 ◽  
Vol 906 ◽  
pp. 121059 ◽  
Author(s):  
Sarah Keller ◽  
Yih Ching Ong ◽  
Yan Lin ◽  
Kevin Cariou ◽  
Gilles Gasser

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3833 ◽  
Author(s):  
Arianna Marucco ◽  
Elisabetta Aldieri ◽  
Riccardo Leinardi ◽  
Enrico Bergamaschi ◽  
Chiara Riganti ◽  
...  

The dispersion protocol used to administer nanomaterials (NMs) in in vitro cellular tests might affect their toxicity. For this reason, several dispersion procedures have been proposed to harmonize the toxicological methods, allowing for the comparison of the data that were obtained by different laboratories. At the same time, several techniques and methods are available to monitor the identity of the NMs in the cell media. However, while the characterization of suspensions of engineered NMs having narrow size distribution may be easily performed, the description of aggregated NMs forming polydispersions is still challenging. In the present study, sub-micrometric/nanometric TiO2, SiO2, and CeO2 were dispersed in cell media by using two different dispersion protocols, with and without albumin (0.5%) and with different sonication procedures. Dynamic Light Scattering (DLS) was used to characterize NMs in stock solutions and culture media. Pitfalls that affect DLS measurements were identified and, guidance on a critical analysis of the results provided. The NMs were then tested for their cytotoxicity (LDH leakage) toward murine macrophages (RAW 264.7) and PMA-activated human monocytes (THP-1). As markers of pro-inflammatory response, nitric oxide (NO) and cytokine IL-1β production were measured on RAW 264.7 and THP-1 cells, respectively. The pre-treatment with albumin added to a strong sonication treatment increases the stability and homogeneity of the suspensions of nanometric samples, but not of the submicrometric-samples. Nevertheless, while TiO2 and CeO2 were non-cytotoxic in any conditions, differences in cytotoxicity, NO, and IL-1β releases were found for the SiO2, depending upon the protocol. Overall, the results suggest that there is no one-fits-all method valid for all NMs, since each class of NMs respond differently. The definition of validated procedures and parameters for the selection of the most appropriate method of dispersion for each class of NM appears to be a more efficacious strategy for the harmonization of the dispersion protocols.


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