Freezing Biological Samples

Scouten, Charles W.; Cunningham, Miles G.

doi:10.1017/s1551929500055218

Cited by 10 publications

(5 citation statements)

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“…Liquid nitrogen is commonly used for freezing biological samples because it can rapidly achieve extremely low temperatures (-210 • C) (Umrath, 1974). However, liquid nitrogen, having an extremely low specific heat constant, boils locally at the contact point with any warmer surface, resulting in a vapor barrier that acts as an insulator and slows the penetration of the cold front within the tissue unpredictably (Scouten and Cunningham, 2006). This unequal cooling makes the tissue and the surrounding embedding medium susceptible to cracking.…”

Section: Optimal Freezing Rate With DI Erent Freezing Mediamentioning

confidence: 99%

A technology platform for standardized cryoprotection and freezing of large-volume brain tissues for high-resolution histology

Kumarasami,

Verma,

Pandurangan

et al. 2023

Front. Neuroanat.

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Understanding and mapping the human connectome is a long-standing endeavor of neuroscience, yet the significant challenges associated with the large size of the human brain during cryosectioning remain unsolved. While smaller brains, such as rodents and marmosets, have been the focus of previous connectomics projects, the processing of the larger human brain requires significant technological advancements. This study addresses the problem of freezing large brains in aligned neuroanatomical coordinates with minimal tissue damage, facilitating large-scale distortion-free cryosectioning. We report the most effective and stable freezing technique utilizing an appropriate choice of cryoprotection and leveraging engineering tools such as brain master patterns, custom-designed molds, and a continuous temperature monitoring system. This standardized approach to freezing enables high-quality, distortion-free histology, allowing researchers worldwide to explore the complexities of the human brain at a cellular level. Our approach combines neuroscience and engineering technologies to address this long-standing challenge with limited resources, enhancing accessibility of large-scale scientific endeavors beyond developed countries, promoting diverse approaches, and fostering collaborations.

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Section: Optimal Freezing Rate With DI Erent Freezing Mediamentioning

confidence: 99%

A technology platform for standardized cryoprotection and freezing of large-volume brain tissues for high-resolution histology

Kumarasami,

Verma,

Pandurangan

et al. 2023

Front. Neuroanat.

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“…It is also possible to use other cooling media, such as isopentane, which provides better penetration of cold into the tissue. Another suggested way to prevent the formation of ice crystals is to saturate the samples with a sucrose solution before freezing [7]. However, this step extends the duration of the whole procedure, which is why the first option was chosen in this study.…”

Section: Discussionmentioning

confidence: 99%

Microscopic Imaging to Visualize the Distribution of Dietary Nucleic Acids in Food Products of Various Origins

Kościelak,

Koziara,

Maria

et al. 2023

Foods

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Dietary nucleic acids (dietNAs) are being increasingly recognized as important food components with nutritional value. However, the precise dietary recommendations for dietNAs are limited, because established methods for determining the quantity and nutritional role of dietNAs are still lacking. One of the tools to narrow this gap could be microscopic imaging, as a convenient approach to visualize the abundance and distribution of dietNAs in food products. With the aid of appropriate bioinformatic elaboration, such images may in future enable the direct semiquantitative estimation of these macromolecules in food products. In the presented study, two methods of preparing microscopic sections and staining them with DNA-specific fluorochromes were used for microscopic imaging of dietNAs in food products of plant and animal origin. Procedures for preparing formalin-fixed paraffin-embedded sections and cryosections were compared in terms of their usefulness for routine food analysis. Both methods turned out equally suitable for visualizing dietNA distribution in animal and plant products. However, the use of cryosections allowed a significantly shorter analysis time and reduced the consumption of organic solvents. Both of these advantages make the cryosection method preferable while establishing a dedicated methodology for routine assessment of dietNAs in the food industry.

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“…Snap-frozen section studies using liquid nitrogen, which has a boiling temperature of minus 195.79 °C, describe that the interaction between the fresh tissue and the liquid nitrogen creates a vapor barrier that leads to an unpredictable freezing pattern that causes cracking of the tissue and OCT making it inadequate for intraoperative frozen section . 12 This could be avoided by using a liquid cooling medium for efficient homogeneous heat extraction such as isopentane, as is usually done for muscle biopsies; however, since this method requires freezing and thawing of the isopentane, which will lead to increased turn-around time, it is not practical for intraoperative use.…”

Section: Discussionmentioning

confidence: 99%

Qualitative Comparison of Cryostat- versus Snap-Frozen Neurosurgical Intraoperative Consultations

et al. 2022

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Background: Frozen sections (FS) are common in neurosurgery to address varied clinical concerns. Artifacts in central nervous system (CNS) FS can be severe and affect or hinder interpretation. We performed a case-control study using a semiquantitative scale: the Histologic Preservation Score (HPS), and a quantitative scale: the Ice Crystal Vacuolization Score (ICVS), to compare the histologic quality yielded by snap- versus cryostat freezing techniques. Material and Methods: All specimens were sectioned in 2 halves, one half was used for FS and the other for permanent evaluation. HPS assigns a distortion score to the FS sample using the non-frozen half as the comparator: 1 = minimal, 2 = slight, 3 = moderate, 4 & 5 = severe. The ICVS is the average size in µm of the 5 largest vacuoles/0.05 mm2, evaluated on digitized slides. Results: 86 CNS-FS were collected: 22 snap- and 64 cryostat-FS. Significant differences in HPS: 2.28 versus 2.84 ( p <0.05) and ICVS 7.47 versus 14.56 ( p < 0.001) were obtained for snap- versus cryostat-FS, respectively. HPS and ICVS showed a strong correlation: R2 = 0.63, p < 0.0001. Histologic distortion was worse for neuroglial than mesenchymal tissue by both methods; however, a significant difference was only observed in cryostat-FS: HPS: 3.23 versus 2.33, p < 0.001; ICVS: 16.86 μm versus 10.26 μm, p < 0.001. Conclusion: Snap-FS yields better histologic quality than cryostat-FS for CNS-FS, and the difference is more pronounced in neuroglial samples. HPS and ICVS correlate strongly, indicating that the histologic quality is inversely proportional to water-crystallization. These results may apply to other areas of surgical pathology.

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Freezing Biological Samples

Cited by 10 publications

References 0 publications

A technology platform for standardized cryoprotection and freezing of large-volume brain tissues for high-resolution histology

A technology platform for standardized cryoprotection and freezing of large-volume brain tissues for high-resolution histology

Microscopic Imaging to Visualize the Distribution of Dietary Nucleic Acids in Food Products of Various Origins

Qualitative Comparison of Cryostat- versus Snap-Frozen Neurosurgical Intraoperative Consultations

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