Biosafe alternative to xylene: A comparative study

Dietary Supplementation of Flaxseed (Linum usitatissimum L.) Alters Ovarian Functions of Xylene-Exposed Mice

The aim of the performed study was to examine the ability of xylene, flaxseed, and their combinations to affect morphological and endocrine indexes of murine ovaries. The 72 indexes of secondary and tertiary follicular cells, oocytes, corpora lutea, and ovarian stroma have been quantified: diameter, markers of proliferation PCNA and apoptosis caspase 3, receptors to FSH, oxytocin, estrogen (alpha and beta), and progesterone. In addition, concentrations of the ovarian hormones progesterone, estradiol, and IGF-I in the blood, as well as their production by isolated ovaries cultured with and without gonadotropins (FSH + LH mixture), were determined using histological, immunohistochemical, and immunoassay analyses. The character of xylene and flaxseed effects on ovarian functions in mice depended on the stage of ovarian folliculogenesis. It was shown that flaxseed could mitigate and prevent the major (63%) effects of xylene on the ovary. In addition, the ability of gonadotropins to affect ovarian hormone release and prevent its response to xylene has been shown. The effects of these additives could be mediated by changes in the release and reception of hormones. These observations suggest that flaxseed and possibly gonadotropins could be natural protectors of a female reproductive system against the adverse effects of xylene.

Cedarwood oil as an alternative to xylene as a clearing agent in histopathological tissue processing - A comparative study

Background:

Clearing in histopathological tissue processing should be able to make the tissues translucent and clear for the tissues to be visible under light microscopy and should render the clearing agent to be miscible with the dehydrant and the impregnation wax in the preceding and following processing steps. Xylene is a gold standard clearing agent but increasing concerns about the potential carcinogenicity, implementing eco-friendly agents in routine histopathology is necessary.

Aim:

The aim of the study is to assess the clearing ability of Cedarwood oil as an alternative to Xylene in routine tissue processing.

Materials & Methods:

The study was carried out in the Department of Oral Pathology and Microbiology. Formalin fixed 50 tissue samples of size 3-7mm were taken and subsequent dehydration done with acetone and alcohol. The dehydrated tissue is later processed using 90ml of Cedarwood oil with few drops of Xylene and Thymol. After clearing the tissues were subjected to impregnation and embedded in paraffin wax, later which sections were made and stained using H & E stain.

Results:

The results of our study on comparison showed better outcome in tissues processed with cedarwood oil than xylene. Statistical Significant correlation was observed in nuclear staining (p value = 0.001) ; cytoplasmic staining (p value = 0.08) and background staining ( p value = 0.045) indicating a positive results on using cedarwood oil as clearing agent.

Conclusion:

The cedarwood oil can be considered as a safer natural alternative to xylene in laboratories. The cedarwood oil is eco - friendly and easily available with enhanced tissue processing qualities.

Biofriendly Substitutes for Xylene in Deparaffinization

Background

Xylene is an aromatic hydrocarbon that is routinely used in histopathological laboratories. It is biohazardous and produces many toxic effects like carcinogenesis. A safer substitute for xylene is necessary to minimize its usage.

Aim

The aim of this study was to evaluate the effectiveness of 1.7% dishwashing solution, 95% lemon water, and 100% coconut oil when compared to xylene as a deparaffinizing agent during hematoxylin and eosin (H&E) staining.

Materials and Methods

Fifteen paraffin-embedded tissue blocks were selected. Four sections were made from each block. One section was stained with conventional H&E method using xylene (group A) as deparaffinizing agent and other three sections were stained with xylene-free H&E method using 1.7% dishwashing solution (group B), 95% lemon water (group C), and 100% coconut oil (group D), respectively. Slides were scored blindly by a single pathologist considering the parameters such as nuclear and cytoplasmic staining; uniformity, clarity, and crispness of staining; and presence or absence of wax retention.

Results

Adequate nuclear staining was noted in 100% of sections of groups A, B, C, and D (P < 0.001), whereas adequate cytoplasmic staining was noted in 93.33% each in groups A, C, and D when compared with 100% in group B (P > 0.05). Uniform staining was present in 80% of groups A and B and in 73.33% of groups C and D (P > 0.05). Clarity of staining was present in 86.66% of groups A and B and in 80% of groups C and D (P > 0.05), whereas crispness of staining was seen in 73.33% of groups A and D, 86.66% of group B, and 80% of group C (P > 0.05). Wax retention was noted in 20% of groups A and B, and 26.66% of groups C and D (P > 0.05). Adequate staining for diagnosis was noted in 100% of group A sections followed by 93.33% in group B, 86.66% in group C, and 80% in group D as compared with 90% in group B (P > 0.05).

Conclusion

Dishwashing solution, lemon water, and coconut oil can be used as safer and cost-effective substitutes to xylene for deparaffinization in H&E staining procedure.

Thyroid cytology smear slides: An untapped resource for ThyroSeq testing

BACKGROUND

Molecular testing of thyroid nodules with indeterminate fine-needle aspiration (FNA) cytology is commonly used to guide patient management and is typically performed on freshly collected FNA samples. In this study, the authors evaluated the performance of the ThyroSeq test in cytology smear slides.

METHODS

Air-dried Diff-Quik (DQ)-stained and alcohol-fixed Papanicolaou (Pap)-stained smears were used to determine required cellularity and sensitivity of mutation detection and to compare ThyroSeq v3 Genomic Classifier (GC) results obtained in cytology smears and fresh FNA samples from the same nodules.

RESULTS

ThyroSeq testing of 31 cytology smears revealed that 25 smears (81%) were adequate for ThyroSeq analysis, including 14 Pap-stained smears (100%) and 11 DQ-stained smears (65%), whereas 6 DQ-stained smears (35%) failed RNA sequencing. The overall accuracy for detecting molecular alterations was 98%, with 100% concordance for mutations and gene expression alterations, 96% concordance for fusions, and 94% concordance for copy number alterations. Cytology smears were adequate for ThyroSeq analysis when at least 200 to 300 cells were present in 1 to 3 slides. ThyroSeq detected all studied mutations down to 5% allele frequency and BRAF mutations down to 1% allele frequency. Testing of smears yielded a positive ThyroSeq GC result in all nodules originally classified as positive.

CONCLUSIONS

Thyroid FNA cytology smear slides with adequate cellularity can be successfully used for ThyroSeq GC testing in approximately 80% of cases, with an even higher success rate in Pap-stained smears. Compared with FNA samples collected into preservative solution, 94% to 100% of different genetic alterations could be accurately detected in smears, validating cytology smears as an alternative for ThyroSeq testing in patients with indeterminate thyroid cytology.

A substitute to xylene in deparaffinization and clearing prior to coverslipping in histopathology

INTRODUCTION:

Deparaffinization and clearing prior to coverslipping are important steps in all staining methods in histopathology. Xylene is the most commonly used agent worldwide. However, xylene is toxic. We evaluated safer alternative dewaxing and clearing agents prior to coverslipping in a histopathology laboratory.

MATERIALS AND METHODS:

Thirteen different fresh surgical tissues were cut into two halves. One half processed using xylene and the other half processed using UltraClear™. Five groups were designed. For each Group of A, B, C, and D, 100 slides were cut from xylene-processed blocks. For Group E, 100 slides were cut from UltraClear™-processed blocks. Group A is the standard method. Group B evaluates UltraClear™ as a dewaxing agent only. Group C evaluates UltraClear™ as a clearing agent prior to coverslipping only. Group D evaluates UltraClear™ as both dewaxing and clearing agents prior to coverslipping. Group E evaluates UltraClear™ as both dewaxing and clearing agents prior to coverslipping. Six parameters were evaluated: nuclear staining, cytoplasmic staining, cell morphology, clarity of staining, uniformity of staining, and cost.

RESULTS:

Groups B, C, and D showed 79% (P = 0.054), 83% (P = 0.221), and 80% (P = 0.079) adequacy when compared with Group A (89%), respectively. However, Group E showed only 76% (P = 0.016) adequacy. UltraClear™ is more expensive than xylene.

CONCLUSION:

UltraClear™ is a promising dewaxing agent. It is also a good clearing agent for use prior to coverslipping in histopathology laboratory. Cost-benefit balance between safety of laboratory workers, good quality staining, and cost-effective strategy needs to be further studied.

Kerosene as an Alternative to Xylene in Histopathological Tissue Processing and Staining: An Experimental Study

Background

Conventional tissue processing is as old as 100 years and still remains the gold standard. Tissue processing involves many steps, of which one of the important steps is clearing. Xylene is one of the common clearing agents used in laboratory, but it is carcinogenic and teratogenic.

Aim

The aim of this study was to substitute conventionally used xylene with kerosene in tissue processing and staining.

Materials and Methods

Thirty bits of chicken tissue samples were collected; each was randomly separated into two groups: tissue processing and staining. Instead of conventional xylene, we used kerosene. The tissue blocks were subjected to sectioning and staining, and finally, they were observed under light microscope.

Results

Tissue samples that were processed and cleared with kerosene showed equal clearing and staining without any alterations of the tissue morphology and cellular details with that of xylene.

Conclusion

Kerosene can be used as a substitute to xylene without posing any health risk or compromising the cellular integrity.

Residual tissue repositories as a resource for population-based cancer proteomic studies

BACKGROUND

Mass spectrometry-based proteomics has become a powerful tool for the identification and quantification of proteins from a wide variety of biological specimens. To date, the majority of studies utilizing tissue samples have been carried out on prospectively collected fresh frozen or optimal cutting temperature (OCT) embedded specimens. However, such specimens are often difficult to obtain, in limited in supply, and clinical information and outcomes on patients are inherently delayed as compared to banked samples. Annotated formalin fixed, paraffin embedded (FFPE) tumor tissue specimens are available for research use from a variety of tissue banks, such as from the surveillance, epidemiology and end results (SEER) registries' residual tissue repositories. Given the wealth of outcomes information associated with such samples, the reuse of archived FFPE blocks for deep proteomic characterization with mass spectrometry technologies would provide a valuable resource for population-based cancer studies. Further, due to the widespread availability of FFPE specimens, validation of specimen integrity opens the possibility for thousands of studies that can be conducted worldwide.

METHODS

To examine the suitability of the SEER repository tissues for proteomic and phosphoproteomic analysis, we analyzed 60 SEER patient samples, with time in storage ranging from 7 to 32 years; 60 samples with expression proteomics and 18 with phosphoproteomics, using isobaric labeling. Linear modeling and gene set enrichment analysis was used to evaluate the impacts of collection site and storage time.

RESULTS

All samples, regardless of age, yielded suitable protein mass after extraction for expression analysis and 18 samples yielded sufficient mass for phosphopeptide analysis. Although peptide, protein, and phosphopeptide identifications were reduced by 50, 20 and 76% respectively, from comparable OCT specimens, we found no statistically significant differences in protein quantitation correlating with collection site or specimen age. GSEA analysis of GO-term level measurements of protein abundance differences between FFPE and OCT embedded specimens suggest that the formalin fixation process may alter representation of protein categories in the resulting dataset.

CONCLUSIONS

These studies demonstrate that residual FFPE tissue specimens, of varying age and collection site, are a promising source of protein for proteomic investigations if paired with rigorously verified mass spectrometry workflows.

Experimental Granulomatous Pulmonary Nocardiosis in BALB/C Mice

Pulmonary nocardiosis is a granulomatous disease with high mortality that affects both immunosuppressed and immunocompetent patients. The mechanisms leading to the establishment and progression of the infection are currently unknown. An animal model to study these mechanisms is sorely needed. We report the first in vivo model of granulomatous pulmonary nocardiosis that closely resembles human pathology. BALB/c mice infected intranasally with two different doses of GFP-expressing Nocardia brasiliensis ATCC700358 (NbGFP), develop weight loss and pulmonary granulomas. Mice infected with 10⁹ CFUs progressed towards death within a week while mice infected with 10⁸ CFUs died after five to six months. Histological examination of the lungs revealed that both the higher and lower doses of NbGFP induced granulomas with NbGFP clearly identifiable at the center of the lesions. Mice exposed to 10⁸ CFUs and subsequently to 10⁹ CFUs were not protected against disease severity but had less granulomas suggesting some degree of protection. Attempts to identify a cellular target for the infection were unsuccessful but we found that bacterial microcolonies in the suspension used to infect mice were responsible for the establishment of the disease. Small microcolonies of NbGFP, incompatible with nocardial doubling times starting from unicellular organisms, were identified in the lung as early as six hours after infection. Mice infected with highly purified unicellular preparations of NbGFP did not develop granulomas despite showing weight loss. Finally, intranasal delivery of nocardial microcolonies was enough for mice to develop granulomas with minimal weight loss. Taken together these results show that Nocardia brasiliensis microcolonies are both necessary and sufficient for the development of granulomatous pulmonary nocardiosis in mice.