Comparative efficacy of cedarwood oil and xylene in hematoxylin and eosin staining procedures: An experimental study

MALDI-TOF imaging analysis of benzalkonium chloride penetration in ex vivo human skin

Benzalkonium chloride (BZK), alkyldimethylbenzlamonium chloride, is a cationic surfactant that is used as an antiseptic. BZK is classified as a quaternary ammonium compound composed of molecules of several alkyl chains of differing lengths, that dictate its effectiveness towards different microbes. As a result, BZK has become one of the most used preservatives in antibacterial solutions. Despite its widespread use, it is not clear whether BZK penetrates human skin. To answer this question, BZK treated skin was analyzed using matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry imaging. Solutions containing BZK and differing excipients, including citric acid, caprylyl glycol, and vitamin E, were applied ex vivo to excised human skin using Franz diffusion cells. Treated skin was embedded in gelatin and sectioned prior to MALDI-TOF imaging. BZK penetrates through the epidermis and into the dermis, and the penetration depth was significantly altered by pH and additives in tested solutions.

Evaluation of the efficacy of hematoxylin and eosin stain when xylene is completely replaced by turpentine or kerosene oil - A comparative study for oral tissues

Background

Microscopic examination of cells and tissues requires the preparation of very thin and good-quality sections mounted on glass slides and appropriately stained to demonstrate normal and abnormal structures. Before this step, the tissue must undergo preparatory treatment known as tissue processing. The various stages of tissue processing are dehydration, clearing, impregnation, and embedding, each with a particular duration for proper completion of the process. Xylene is the most frequently used clearing agent whose carcinogenic potential is well documented. Hence, attempts were made to substitute xylene with a biosafe clearing agent. The present study aimed to evaluate and compare the efficacy of hematoxylin and eosin stain (H and E stain) when xylene is completely replaced by turpentine or kerosene oil.

Materials and Methods

A total number of 50 tissue samples were taken in the study, which included 40 study samples and 10 controls. All the samples were randomly separated into three groups and routine tissue processing and H and E staining were performed. The result was further subjected to statistical analysis by using Fisher's exact test. Group-1: Ten tissue samples were processed and H and E staining was done in xylene. Group-2: Twenty tissue samples were processed and H and E staining was done in turpentine oil. Group-3: Twenty tissue samples were processed and H and E staining was done in kerosene oil.

Results

Nuclear staining, cell morphology, and uniformity of staining were better in kerosene sections, while cytoplasmic and clarity of staining of turpentine sections were comparable with xylene sections.

Conclusion

Turpentine and kerosene as clearing agents can be used in the future with certain modifications in their concentration and routine staining protocol.

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.

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.

Natural Alternatives for Chemicals Used in Histopathology Lab- A Literature Review

Histopathology lab is the place where the specimen gets processed and stained to view under microscope for interpretation. Exposure to the chemicals used in these processes cause various health hazards to the laboratory technicians, pathologists, and scientists working in the laboratory. Hence, there is a dire need to introduce healthy and bio-friendly alternatives in the field. This literature review explores the natural products and their efficiency to be used as alternatives for chemicals in the histopathology lab.

Using wintergreen oil for mounting mosquito larvae: a safer alternative to xylene

Permanent mounting of fourth instar mosquito larvae is essential for identifying Aedes spp. This procedure requires extensive exposure to xylene, a clearing agent in the mounting process. We investigated wintergreen oil as a substitute for xylene. Five hundred larvae were mounted on slides to evaluate shrinkage or expansion of specimens after clearing using xylene or wintergreen oil. We examined the ventral brush and siphonal hair tufts for species identification and for preservation of morphological characteristics after clearing specimens in xylene or wintergreen oil. Shrinkage of the length of whole larvae and width of the head, thorax and abdomen after mounting was significantly greater after clearing with xylene than with wintergreen oil. The length of the comb scale nearest the ventral brush was similar for both clearing agents. The clarity of the specimens after mounting was improved by clearing with wintergreen oil, but the integrity of the ventral brush and siphonal hair tufts were similar for both clearing agents.