Significance of the Application of Special Staining Techniques in Toxicological Evaluation

2021 ◽  
Author(s):  
Mitsuo Ohtsuki ◽  
Michael Sogard

Structural investigations of biological macromolecules commonly employ CTEM with negative staining techniques. Difficulties in valid image interpretation arise, however, due to problems such as variability in thickness and degree of penetration of the staining agent, noise from the supporting film, and artifacts from defocus phase contrast effects. In order to determine the effects of these variables on biological structure, as seen by the electron microscope, negative stained macromolecules of high density lipoprotein-3 (HDL3) from human serum were analyzed with both CTEM and STEM, and results were then compared with CTEM micrographs of freeze-etched HDL3. In addition, we altered the structure of this molecule by digesting away its phospholipid component with phospholipase A2 and look for consistent changes in structure.


Author(s):  
G. R. Mackay ◽  
M. L. Mead

Color contrasting of 1 to 2 micron sections of plastic embedded biological material is an important adjunct to electron microscopy. The procedures in general use today are simple and rapid giving monochromatic results, e.g., toluidine blue. Although many di- and polychromatic histologic staining techniques have been modified to obtain a counterstaining effect with plasticembedded tissue, the methods are usually undesirable for routine work because they are time consuming, complicated and often defy good reproducibility.


Author(s):  
C. N. Sun ◽  
H. J. White ◽  
E. J. Towbin

Diabetes insipidus and compulsive water drinking are representative of two categories of antidiuretic hormone (ADH) lack. We studied a strain of rats with congenital diabetes insipidus homozygote (DI) and normal rats on an isocaloric fortified dilute milk diet. In both cases, the collecting tubules could not concentrate urine. Special staining techniques, Alcian Blue-PAS for light microscopy and lanthanum nitrate for electron microscopy were used to demonstrate the changes in interstitial mucopolysaccharides (MPS). The lanthanum staining was done according to the method of Khan and Overton.Electron microscopy shows cytoplasmic lesions, vacules, swelling and degenerating mitochondria and intercellular spaces (IS) in the collecting tubule cells in DI and rats on milk diet.


Author(s):  
A. C. Reimschuessel ◽  
V. Kramer

Staining techniques can be used for either the identification of different polymers or for the differentiation of specific morphological domains within a given polymer. To reveal morphological features in nylon 6, we choose a technique based upon diffusion of the staining agent into accessible regions of the polymer.When a crystallizable polymer - such as nylon 6 - is cooled from the melt, lamellae form by chainfolding of the crystallizing long chain macromolecules. The regions between adjacent lamellae represent the less ordered amorphous domains into which stain can diffuse. In this process the lamellae will be “outlined” by the dense stain, giving rise to contrast comparable to that obtained by “negative” staining techniques.If the cooling of the polymer melt proceeds relatively slowly - as in molding operations - the lamellae are usually arranged in a radial manner. This morphology is referred to as spherulitic.


2020 ◽  
Vol 77 (2) ◽  
pp. 353-360
Author(s):  
Nadia Malik ◽  
Mahmood Ahmad ◽  
Muhammad Minhas ◽  
Ruqia Tulain ◽  
Ikrima Khalid ◽  
...  

2011 ◽  
Vol 4 (5) ◽  
pp. 26-30 ◽  
Author(s):  
Cherif H.S Cherif H.S ◽  
◽  
Saidi F Saidi F ◽  
Guedioura A Guedioura A

2017 ◽  
Vol 68 (8) ◽  
pp. 1944-1945
Author(s):  
Catalin Stefan ◽  
Gabriel Lostun ◽  
Alexandra Lostun

Head and neck cancer represents 3% of malignancies, and it is associated with high mortality due to advanced stage diagnosis. In early stages, the symptomatology can either be absent or be very common, misleading the patient who often ignores it. Early diagnosis of head and neck neoplasia is essential for a favorable long-term outcome. Lately new in vivo examination techniques were developed, and older ones have been improved. Today, in vivo staining techniques are an important tool in the diagnostic of head and neck cancer. Lugol iodine staining method provides valuable information concerning the tumor, allowing the surgeon to differentiate premalignant and malignant lesions.


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.


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