A histochemical comparison of methylene-blue/acid fuchsin with hematoxylin and eosin for differentiating calcification of stromal tissue

An off-the-shelf decellularized and sterilized human bone-ACL-bone allograft for anterior cruciate ligament reconstruction

Approximately 1% of active individuals participating in sports rupture their anterior cruciate ligaments (ACL) every year, which is currently reconstructed using tendon autografts. Upon reconstruction, clinical issues of concern are ACL graft rupture, persistent knee instability, limited return to sports, and early onset of osteoarthritis (OA). This happens because tendon autografts do not have the same compositional, structural, and mechanical properties as a native ACL. To overcome these problems, we propose to use decellularized bone-ACL-bone allografts in ACL reconstruction (ACLR) as a mechanically robust, biocompatible, and immunologically safe alternative to autografts. Here, a decellularization protocol combined with sterilization using supercritical carbon dioxide (scCO₂) was used to thoroughly decellularize porcine and human ACLs attached to tibial and femoral bone blocks. The specimens were named ultrACLean and their compositional, structural, and mechanical properties were determined. Our results indicate that: 1) decellularization of ultrACLean allografts leads to the removal of nearly 97% of donor cells, 2) ultrACLean has mechanical properties which are not different to native ACL, 3) ultrACLean maintained similar collagen content and decreased GAG content compared to native ACL, and 4) ultrACLean is not cytotoxic to seeded tendon-derived cells in vitro. Results from an in vivo pilot experiment showed that ultrACLean is biocompatible and elicits a moderate immunological response. In summary, ultrACLean has proven to be a mechanically competent and biocompatible graft with the potential to be used in ACLR surgery.

A novel rat model of interbody fusion based on anterior lumbar corpectomy and fusion (ALCF)

BACKGROUND

Rats have been widely used as experimental animals when performing fundamental research because they are economical, rapidly reproducing, and heal quickly. While the rat interbody fusion model has been applied in basic studies, existing rat models generally have shortcomings, such as insufficiently simulating clinical surgery. The purpose of this study was to develop a novel rat model of interbody fusion which more closely represents clinical surgery.

METHODS

The internal fixation was designed based on physical measurements of the rats' lumbar spine. Then, ten rats divided into two groups (A and B) underwent anterior lumbar corpectomy and fusion of the L5 vertebrae. Groups A and B were sacrificed four and 8 weeks post-surgery, respectively. Micro-CT and histological examination were used to evaluate the model. Fusion rate, bone volume fraction (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th), and the area ratio of newly formed bone (NB) were calculated for quantitative analysis.

RESULTS

Based on the L5 body dimensions of individual rats, 3D-printed titanium cage of the appropriate size were printed. The operations were successfully completed in all ten rats, and X-ray confirmed that internal fixation was good without migration. Micro-CT suggested that fusion rates in group B (100%) were greater than group A (40%, P < 0.05). The BV/TV (B: 42.20 ± 10.50 vs. A: 29.02 ± 3.25, P < 0.05) and Tb.N (B: 4.66 ± 1.23 vs. A: 1.97 ± 0.40, P < 0.05) were greater in group B than A, and the Tb.Th in group B was lower than group A (B: 0.10 ± 0.04 vs. A: 0.15 ± 0.02, P < 0.05). Histomorphometry results demonstrated that the area ratio of NB in group B were greater than group A (B: 35.72 ± 12.80 vs. A: 12.36 ± 16.93, P < 0.05).

CONCLUSION

A rat interbody fusion model based on anterior lumbar corpectomy and fusion has successfully been constructed and verified. It could provide a new choice for fundamental research using animal models of spinal fusion.

Natural stain (Kumkum) formulated by the extract of Curcuma aromatica and slaked lime in histostaining of oral tissues: An observational study

Background

The pharmacological actions of Curcuma aromatica (wild turmeric) such as anti-inflammatory, antitumor, antifungal, antimicrobial and wound healing have been recognized since ages. However, its role as a natural histological stain has not been explored till date.

Aim

To evaluate the efficacy of natural substance-Kumkum prepared from the extract of C. aromatica and slaked lime in staining the biopsied oral tissues.

Materials and Methods

A cohort study that used 60 formalin fixed paraffin embedded soft and hard tissue specimens from institutional archives were subjected to sectioning and stained using Kumkum and hematoxylin and eosin (H and E). The slides were evaluated for their staining efficacy and results were statistically analyzed using Wilcoxon signed-rank test and Independent 't' test.

Results

The mean of the overall parameters assessed for staining efficacy did not show statistically significant difference between the study groups in normal and pathological specimens for tooth (P = 0.410 and 0.484), bone (P = 0.133 and 0.157) and soft tissues (P = 0.186 and 0.113), respectively. This suggests that Kumkum staining efficacy is equivalent to that of routine H and E for oral tissues. Structures such as dentinoenamel junction, dentinal tubules, incremental lines of cementum, reversal and resting lines, osteocytic canaliculi, mature and immature bone could be appreciated better in Kumkum stained slides, thereby rendering a special staining property to Kumkum stain.

Conclusion

To our knowledge, this study is the first of its kind to have used Kumkum stain obtained from C. aromatica for the differentiation of the components of tooth, bone and soft tissue structures in histostaining of oral tissues. The naturally prepared Kumkum stain possesses dual staining property both in routine and differential staining. This facilitates diagnosis of fibro-osseous lesions, bony, collagen and muscular pathologies. The natural stain also finds application in forensic odontology for age estimation.

Specific Oxide Nanoclusters Enhance Intracellular Reactive Oxygen Species for Cancer-Targeted Therapy

Bio-nanotechnology based cancer therapeutics exponentially increase every year. A therapeutic strategy to induce intracellular reactive oxygen species (ROS) has received promising success in oncotherapy. In this study, the new strategy has been exploited by the treatment of iridium (Ir) and Fe²⁺ ions with cancer cells to biosynthesize the biocompatible fluorescent iridium oxide (IrO₂) and iron oxide nanoclusters (NCs) under the specific redox heterogeneous microenvironment of these diseased cells and tumors. The hydroxyl radical produced by the presence of Fe²⁺ and H₂O₂ in cancer cells apparently increased the ROS level in cancer cells during the process of biosynthesized NCs and, hence, simultaneously instigated apoptosis of relevant cells. Therefore, intracellular ROS-mediated in situ biosynthesis of IrO₂ and iron oxide NCs may also act as anticancer agents and provide a promising pathway for targeted cancer therapy.

Staining efficacy assessment of a differential routine and special stains for pathological stromal calcifications in maxillofacial lesions

Head and neck connective tissue lesions may have diverse calcifications within the fibrous connective tissue stroma. The perplexity involved in the identification and determination of the nature or degree of calcification through routine hematoxylin and eosin (H&E) stains necessitates the usage of a specific, simple, and cost- and time-effective differential staining techniques. The aim of the present study was to develop criteria to distinguish bone formation from bone resorption using methylene blue-acid fuchsin (MB/AF) stain and the role of collagen fibers in the identification of stromal calcifications using polarizing microscopy with picrosirius red stain. Twenty cases with pathological diagnoses for various stromal calcifications in maxillofacial lesions were retrieved from the departmental archives. Decalcified formalin fixed paraffin embedded tissue sections were stained with hematoxylin and eosin, Masson's trichrome (MT), methylene blue-acid fuchsin (MB/AF), and picrosirius red. The stained sections were assessed to identify the calcifications found in the surrounding connective tissue stroma. It was observed that most cases showed maximum staining intensity with MB/AF stain as compared to the other staining methods. Moreover, the results suggested that contrast between calcification and stromal soft tissue was best distinguished with the MB/AF stain except in the case of dystrophic calcifications. Along with this, polarizing microscopy with picrosirius red enables better characterization of stromal components. Although the H&E stain and a connective tissue stain i.e. Masson's trichrome, are employed routinely in histopathology; the use of special stains such as MB-AF and picrosirius red facilitates the identification of calcifications from the stromal tissues.

Comparison of Hematoxylin and Eosin Stain with Modified Gallego's Stain for Differentiating Mineralized Components in Ossifying Fibroma, Cemento-ossifying Fibroma, and Cementifying Fibroma

Objective

The nature of calcifications in fibro-osseous lesions is difficult to differentiate under hematoxylin and eosin (H and E) stain and could be misleading. Special stains could be used. Modified Gallego's stain is a differential stain for hard tissues, which has been discussed recently in the literature.

Methods

Retrospective study was done from June to December 2015 to differentiate various types of mineralized tissues in ossifying fibroma (OF), cemento-OF (COF), and cementifying fibroma (CF), using modified Gallego's stain and its correlation with H and E stain. Control group comprised of decalcified section of bone, tooth, and odontoma, stained with modified Gallego's stain. Study group comprised of 30 lesions (10 OF, 10 COF, and 10 CF) stained with both modified Gallego's stain and H&E stain. This study did not have any numerical data; therefore, no appropriate statistical test could be performed. Hence, cross tabulation of the categorical data was used followed by descriptive statistical analyses. Results were presented on continuous measurements using mean ± standard deviation, and results on categorical measurements were presented in number (%).

Results

Modified Gallego's staining showed that, out of 10 cases of OF, 9 cases were interpreted as OF; one case of juvenile psammomatoid OF was interpreted as juvenile psammomatoid COF. Out of 10 cases of COF, 4 cases were interpreted as OF. Out of 10 cases of CF, 2 cases were interpreted as COF and 3 cases as OF.

Conclusions

Fibro-osseous lesions are difficult to diagnose using H and E staining alone. Modified Gallego's stain could be a best adjunct.

Real-Time Multimodal Bioimaging of Cancer Cells and Exosomes through Biosynthesized Iridium and Iron Nanoclusters

Multimodal bioimaging is a powerful tool for visualizing the abnormal state at the target site of the related disease. In this study, we used multimodal imaging techniques such as computed tomography, fluorescence, and magnetic resonance imaging to improve early and precise diagnosis of tumor. Herein, we reported the facile in situ biosynthesis of iridium and iron oxide nanoclusters (NCs) in cancer cells or tumor tissue. These NCs are used as a multimodal bioimaging probe to improve the image sensitivity and specificity toward the tumor. These NCs are applied for the in vivo multimodal imaging in the form of an imaging probe capable of enhancing the sensitivity of the image and specificity toward the tumor tissue. Our observation demonstrates that highly luminescent and magnetic NCs are not only biocompatible but also tumor-targeted because NC formation does not take place in normal cells and tissues. In addition, we isolated exosomes and the biosynthesized NCs internalized within exosomes, and these exosomes can be used as cancer biomarkers.