Brain Sample Preparation After Performing in Utero Electroporation to Proliferating and Differentiated Cells in the Developing Mouse Neocortex

In utero electroporation (IUE) enables labeling and manipulating specific types of cells by introducing DNA plasmids with desired promoters. After the surgery, mouse brains are fixed at any stage and analyzed after staining using specific antibodies. Here, we describe the flow of the IUE experiment from the preparation to microscopic observations.

Sticker method for preparation of frozen section using adhesive film

BACKGROUND

In basic research, especially animal experiments, tissue histology with preserved organ morphology is essential, and the reliability of experiments depends on the quality of tissue sections. Frozen sections adequately maintain the antigenicity of tissues and are suitable for immunohistochemistry. However, thin frozen sections are often difficult to prepare from specimens. Therefore, a simple and fast method with a high success rate of specimen preparation is desired.

NEW METHOD

In this study, we propose the "Sticker method," for preparing frozen sections using adhesive film, which is easy and maintains the whole organ morphology even in frozen section.

RESULTS

This method requires a simple adhesive film, and other components of general tissue fixation method with embedding medium. The present sticker method showed a higher success rate than the conventional method in preparing frozen sections.

COMPARISON WITH EXISTING METHOD

Fragile frozen sections can be prepared with intact whole organ morphology without wrinkles. The advantage of the present method is that tissues can be embedded using only a common embedding medium and besides the adhesive film, no other special equipment is required. Furthermore, this method can be easily used by virtually every lab performing cryosections.

CONCLUSIONS

The sticker method using adhesive films is characterized by a shortened preparation time and increased success rate of frozen section compared with conventional method.

Large Angle Optical Access in a Sub-Kelvin Cryostat

The development of lens-antenna-coupled aluminum-based microwave kinetic inductance detectors (MKIDs) and on-chip spectrometers needs a dedicated cryogenic setup to measure the beam patterns of the lens-antenna system over a large angular throughput and broad frequency range. This requires a careful design since the MKID has to be cooled to temperatures below 300 mK to operate effectively. We developed such a cryostat with a large opening angle θ = ± 37 . 8 ∘ and an optical access with a low-pass edge at 950 GHz . The system is based upon a commercial pulse tube cooled 3 K system with a 4 He - 3 He sorption cooler to allow base temperatures below 300 mK . A careful study of the spectral and geometric throughput was performed to minimize thermal loading on the cold stage, allowing a base temperature of 265 mK . Radio-transparent multi-layer-insulation was employed as a recent development in filter technology to efficiently block near-infrared radiation.

Pre- and Post-embedding Immunogold Labeling of Tissue Sections

Despite the improved resolution capacities of fluorescence microscopy over the last 20 years, localization of specific proteins at the ultrastructural level with gold-conjugated antibodies remains a valuable technique in the cell biological tool chest. Ultrastructural immunolocalization of specific proteins in tissues rather than in cultured cells is often advantageous because, in tissues, the interactions between different cell types and with the extracellular matrix are maintained. Here, we describe two immunogold labeling procedures to localize at the ultrastructural level one or more proteins. In the first procedure (pre-embedding), micrometer-thick tissue cryostat sections are immunostained prior to embedding for obtaining ultrathin sections suitable for TEM, while in the second procedure (post-embedding), tissues are embedded in a hydrophobic resin such as Lowicryl K4M and ultrathin sections are first obtained and then immunolabeled. While the former method is better at generating strong immunolabeling, the latter is better at preserving ultrastructure.

Intra-operative Diagnosis of Breast Lesions by Imprint Cytology and Frozen Section with Histopathological Correlation

INTRODUCTION

The most common malignant tumour among women is breast carcinoma. Early lesions of the breast including carcinoma are potentially curable if treated properly in the era of breast conservative therapy. For this purpose different diagnostic strategies are in practice. Intra operative Imprint Cytology (IC) and Frozen Section (FS) have a role in spite of the intense recognition of aspiration cytology in the following settings: inconclusive cytological/core biopsy findings; for evaluation of lumpectomy margins and intra operative nodal status. Both IC and FS are dependable intra operative diagnostic consultation modalities and provide accurate results in minutes thereby making appropriate therapeutic decision.

AIM

To study the IC and FS features of breast lesions with correlation of final Histopathologic (HP) diagnosis and to determine its diagnostic accuracy.

MATERIALS AND METHODS

This was a descriptive cross-sectional study conducted in the Department of Pathology, JSS Medical College, JSS University, Mysuru over a period of two years (October 2011-September 2013). A total of 62 cases of surgically resected breast specimens were evaluated for features of IC, FS and correlation with HP diagnosis. After describing gross features, representative tissue fragment was taken, three imprint smears were made and same tissue fragment was subjected to FS and later for routine HP processing. Slides prepared by IC, FS were interpreted and later correlated with HP diagnosis. Statistical analysis was done with SPSS for windows (version 16.0) by applying appropriate tests.

RESULTS

Out of 62 cases, 33(53.23%) were malignant and 29(46.77%) were benign. Sensitivity, specificity and accuracy of IC were 100%, 96.43% and 98.36% and for FS were 100%, 96.55% and 98.39% respectively. p-value for both were <0.001 indicating significant correlation with HP study.

CONCLUSION

IC is a simple, accurate, rapid and cost effective diagnostic tool intra operatively where services for FS are not available. It preserves crisp cellular and nuclear detail. FS tissue architecture strongly approximates permanent HP sections but is frequently hampered by freezing artifact. But FS is able to differentiate carcinoma in situ and infiltrative lesions from benign breast lesions. Thus, IC and FS together offer a more reliable diagnosis; hence, it is always useful to prepare both the slides intra operatively. HP study still remains the gold standard in final diagnosis of any breast lesion. In surgical pathology, the correlation of intra operative IC and FS diagnosis with the final HP diagnosis form an essential part of quality assurance activity.

Optimization and validation of cryostat temperature conditions for trans-reflectance mode FTIR microspectroscopic imaging of biological tissues

In Fourier transform infrared (FTIR) microspectrocopy, the tissue preparation method is crucial, especially how the tissue is cryo-sectioned prior to the imaging requires special consideration. Having a temperature difference between the cutting blade and the specimen holder of the cryostat greatly affects the quality of the sections. Therefore, we have developed an optimal protocol for cryo-sectioning of biological tissues by varying the temperature of both the cutting blade and the specimen holder. Using this protocol, we successfully cryo-sectioned four different difficult-to-section tissues including white adipose tissue (WAT), brown adipose tissue (BAT), lung, and liver. The optimal temperatures that required to be maintained at the cutting blade and the specimen holder for the cryo-sectioning of WAT, BAT, lung, and liver are (−25, −20 °C), (−25, −20 °C), (−17, −13 °C) and (−15, −5 °C), respectively. The optimized protocol developed in this study produced high quality cryo-sections with sample thickness of 8–10 μm, as well as high quality trans-reflectance mode FTIR microspectroscopic images for the tissue sections.

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Use of cryostat technique to make thin sections of biological samples for FTIR microspectroscopy imaging.

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Optimized cryostat temperature conditions by varying the temperatures at the cutting blade and specimen holder to obtain high quality sections of difficult-to-handle tissues.

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FTIR imaging is used to obtain chemical information from cryo-sectioned samples with no interference of the conventional paraffin-embedding agent and chemicals.

Conceptual design of the superconducting magnet for the 250 MeV proton cyclotron

BACKGROUND

The superconducting cyclotron is of great importance to treat cancer parts of the body. To reduce the operation costs, a superconducting magnet system for the 250 MeV proton cyclotron was designed to confirm the feasibility of the superconducting cyclotron.

FINDINGS

The superconducting magnet system consists of a pair of split coils, the cryostat and a pair of binary high temperature superconductor current leads. The superconducting magnet can reach a central magnetic field of about 1.155 T at 160 A. The three GM cryocooler with cooling capacities of 1.5 W at 4.5 K and 35 W at 50 K and one GM cryocooler of 100 W at 50 K were adopted to cool the superconducting magnet system through the thermosiphon technology.

CONCLUSION

The four GM cryocoolers were used to cool the superconducting magnet to realize zero evaporation of the liquid helium.