Procedure for Collection, Preservation and Forwarding of Biological Sample for Toxicological Analysis

Author(s):  
AK Jaiswal ◽  
Tabin Millo
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.


2019 ◽  
Vol 26 (1) ◽  
pp. 177-196 ◽  
Author(s):  
Mateusz Kacper Woźniak ◽  
Marek Wiergowski ◽  
Jacek Namieśnik ◽  
Marek Biziuk

Background:Ethyl alcohol is the most popular legal drug, but its excessive consumption causes social problems. Despite many public campaigns against alcohol use, car accidents, instances of aggressive behaviour, sexual assaults and deterioration in labor productivity caused by inebriated people is still commonplace. Fast and easy diagnosis of alcohol consumption is required in order to introduce proper and effective therapy, and is crucial in forensic toxicology analysis. The easiest method to prove alcohol intake is determination of ethanol in body fluids or in breath. However, since ethanol is rapidly metabolized in the human organism, only recent consumption can be detected using this method. Because of that, the determination of alcohol biomarkers was introduced for monitoring alcohol consumption over a wider range of time.Objective:The objective of this study was to review published studies focusing on the sample preparation methods and chromatographic or biochemical techniques for the determination of alcohol biomarkers in whole blood, plasma, serum and urine.Methods:An electronic literature search was performed to discuss possibilities and limitations of application of alcohol biomarkers in toxicological analysis.Results:Authors described the markers of alcohol consumption such as: ethanol, its nonoxidative metabolites (ethyl glucuronide, ethyl sulfate, phosphatidylethanol, ethyl phosphate, fatty acid ethyl esters) and oxidative metabolites (acetaldehyde and acetaldehyde adducts). We also discussed issues concerning the detection window of these biomarkers, and possibilities and limitations of their use in routine analytical toxicology for monitoring alcohol consumption or sobriety during alcohol therapy.


2019 ◽  
Vol 19 (5) ◽  
pp. 667-676
Author(s):  
José R. Santin ◽  
Gislaine F. da Silva ◽  
Maria V.D. Pastor ◽  
Milena F. Broering ◽  
Roberta Nunes ◽  
...  

Background: It was recently demonstrated that the phthalimide N-(4-methyl-phenyl)-4- methylphthalimide (MPMPH-1) has important effects against acute and chronic pain in mice, with a mechanism of action correlated to adenylyl cyclase inhibition. Furthermore, it was also demonstrated that phthalimide derivatives presented antiproliferative and anti-tumor effects. Considering the literature data, the present study evaluated the effects of MPMPH-1 on breast cancer bone metastasis and correlated painful symptom, and provided additional toxicological information about the compound and its possible metabolites. Methods: In silico toxicological analysis was supported by in vitro and in vivo experiments to demonstrate the anti-tumor and anti-hypersensitivity effects of the compound. Results: The data obtained with the in silico toxicological analysis demonstrated that MPMPH-1 has mutagenic potential, with a low to moderate level of confidence. The mutagenicity potential was in vivo confirmed by micronucleus assay. MPMPH-1 treatments in the breast cancer bone metastasis model were able to prevent the osteoclastic resorption of bone matrix. Regarding cartilage, degradation was considerably reduced within the zoledronic acid group, while in MPMPH-1, chondrocyte multiplication was observed in random areas, suggesting bone regeneration. Additionally, the repeated treatment of mice with MPMPH-1 (10 mg/kg, i.p.), once a day for up to 36 days, significantly reduces the hypersensitivity in animals with breast cancer bone metastasis. Conclusion: Together, the data herein obtained show that MPMPH-1 is relatively safe, and significantly control the cancer growth, allied to the reduction in bone reabsorption and stimulation of bone and cartilage regeneration. MPMPH-1 effects may be linked, at least in part, to the ability of the compound to interfere with adenylylcyclase pathway activation.


1997 ◽  
Vol 3 (S2) ◽  
pp. 1081-1082
Author(s):  
I. Angert ◽  
W. Jahn ◽  
K.C. Holmes ◽  
R.R. Schröder

Understanding the contrast formation mechanism in the EM is one of the prerequisites for artefact-free reconstruction of biological structures from images. We found that the normally used correction of contrast formation applied to zero energy loss filtered images corrupted spatial resolution. Therefore the contribution of contrast formed by inelastic electrons was reconsidered, including partial coherence of inelastically scattered electrons and lens aberrations of the microscope. Based on this, a complete description of the zero-loss contrast transfer function (CTF) is now possible.We used tobacco mosaic virus (TMV), a biological sample known at atomic resolution, for definition of optimum CTF-parameters to reconstruct defocus series from an EFTEM LEO 912. CTF theory as known so far describes image contrast in the weak phase approximation as a linear sum of amplitude and phase contrast. The contribution of amplitude contrast (ratio of amplitude to phase contrast A/P) was determined to be between 7% and 5 % for unfiltered images and 12-14 % for zero-loss filtered images. However, in a filter microscope we remove electrons from the image, so we expect a higher amplitude contrast than in non-filtered images.


2020 ◽  
Vol 24 ◽  
pp. 101002 ◽  
Author(s):  
Tássia Venga Mendes ◽  
Lidiane Silva Franqui ◽  
Mariane Gonçalves Santos ◽  
Célio Wisniewski ◽  
Eduardo Costa Figueiredo

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