The detection methods currently available for protein aggregation in neurological diseases

Protein aggregation is a pathological feature in various neurodegenerative diseases and is thought to play a crucial role in the onset and progression of neurological disorders. This pathological phenomenon has attracted increasing attention from researchers, but the underlying mechanism has not been fully elucidated yet. Researchers are increasingly interested in identifying chemicals or methods that can effectively detect protein aggregation or maintain protein stability to prevent aggregation formation. To date, several methods are available for detecting protein aggregates, including fluorescence correlation spectroscopy, electron microscopy, and molecular detection methods. Unfortunately, there is still a lack of methods to observe protein aggregation in situ under a microscope. This article reviews the two main aspects of protein aggregation: the mechanisms and detection methods of protein aggregation. The aim is to provide clues for the development of new methods to study this pathological phenomenon.

Quantitative assessment of H&E staining for pathology: development and clinical evaluation of a novel system

BACKGROUND

Staining tissue samples to visualise cellular detail and tissue structure is at the core of pathology diagnosis, but variations in staining can result in significantly different appearances of the tissue sample. While the human visual system is adept at compensating for stain variation, with the growth of digital imaging in pathology, the impact of this variation can be more profound. Despite the ubiquity of haematoxylin and eosin staining in clinical practice worldwide, objective quantification is not yet available. We propose a method for quantitative haematoxylin and eosin stain assessment to facilitate quality assurance of histopathology staining, enabling truly quantitative quality control and improved standardisation.

METHODS

The stain quantification method comprises conventional microscope slides with a stain-responsive biopolymer film affixed to one side, called stain assessment slides. The stain assessment slides were characterised with haematoxylin and eosin, and implemented in one clinical laboratory to quantify variation levels.

RESULTS

Stain assessment slide stain uptake increased linearly with duration of haematoxylin and eosin staining (r = 0.99), and demonstrated linearly comparable staining to samples of human liver tissue (r values 0.98-0.99). Laboratory implementation of this technique quantified intra- and inter-instrument variation of staining instruments at one point in time and across a five-day period.

CONCLUSION

The proposed method has been shown to reliably quantify stain uptake, providing an effective laboratory quality control method for stain variation. This is especially important for whole slide imaging and the future development of artificial intelligence in digital pathology.

Comparison of different lipid staining methods in human meibomian gland epithelial cells

This study aimed to compare the utility of four different dyes for intracellular lipid detection in immortalized human meibomian gland epithelial cells (IHMGECs). IHMGECs were cultured in a serum-containing medium for 10 days in the presence or absence of Roxadustat (Roxa), a known inducer of IHMGEC differentiation. Cells were then fixed and stained with Oil Red O (ORO), Sudan III (SIII), LipidTOX green (LT), or Nile Red (NR). IHMGECs were evaluated for the number, size, and area of stained intracellular lipid vesicles or the intensity of staining using bright field (ORO, SIII) or fluorescence (LT, NR) microscopy. Data were captured with ImageJ and analyzed with Student's two-tailed t-test. Our findings demonstrate that different staining methods can yield significantly different patterns of intracellular lipid quantity and/or distribution in IHMGECs. ORO and SIII significantly increased the size and area of lipid-containing vesicles in Roxa-treated cells. Neither stain showed a change in the number of vesicles during IHMGEC differentiation. Vesicle size was significantly greater in cells stained with ORO, as compared to SIII. In addtion, LT, but not NR, showed a significant increase in intracellular lipid intensity in IHMGECs following Roxa -induced differentiation. Our results demonstrate significant differences in the distribution patterns and intensities of lipid-containing vesicles in IHMGECs after staining with ORO, SIII, LT, and NR. ORO, SIII, and LT, but not NR staining, are helpful methods to help identify and quantitate the extent of intracellular lipid accumulation during IHMGEC differentiation.

Routine elastin staining improves venous invasion detection in colorectal carcinoma

BACKGROUND

Colorectal carcinoma is the second most common cause of cancer-related deaths in North America. Invasion of tumor cells into lymphatic and blood vessels is an imperative step in the metastatic progression of colorectal carcinoma.

OBJECTIVES

This is a before-and-after study conducted by the Department of Pathology and Laboratory Medicine of Mount Sinai Medical Center of Florida to assess the impact on venous invasion (VI) detection by implementing routine elastin staining on all tumor-containing blocks per case, where feasible, in colorectal carcinoma (CRC) resection specimens.

METHODS

Clinicopathological parameters of CRC specimens were collected from January until December 2021 (n = 93) for the pre-implementation cohort and from January until December 2022 (n = 61) for the post-implementation cohort.

RESULTS

VI detection was significantly increased in the post-implementation cohort at a rate of 50.8 % compared to only 18.6 % in the pre-implementation cohort. The majority of VI identified in the pre-implementation cohort was extramural (61.5 %), whereas in the post-implementation cohort it was intramural (41.9 %). On univariate analysis, implementation of routine elastin stain was associated with strikingly increased VI detection rates (OR = 4.5, p-value < 0.001). On multivariate analysis, after adjusting for other clinicopathologic variables, elastin staining retained its independent statistically significant impact on VI detection (OR = 2.6, p-value = 0.034). Of note, there were no significant differences in the pre- and post-implementation cohorts in the frequency of nodal metastases, tumor extent, histologic grade, perineural invasion, T stage or M stage.

CONCLUSION

Based on our results and what has been published recently, we confirm an increase in the VI detection rate after implementing routine elastin staining on all tumor-containing blocks in CRC resection specimens.

Crude extracts from Allium cepa skin and Sorghum bicolor seed can provide as non-toxic and eco-friendly cytoplasmic stains

Introduction

Staining is an important histological process; however, the use of non-toxic and environmentally friendly products is generally required. We explored the staining quality of two natural plants, Allium cepa skin and Sorghum bicolor seed extract on the cytoplasm.

Materials and methods

Distilled water at 37 °C and 1% acid-ethanol were respectively used to extract the dyes from Allium cepa skin and Sorghum bicolor seed.

Result

The application of these two dyes on rodent tissue showed an excellent cytoplasmic histomorphology.

Conclusion

Allium cepa skin and Sorghum bicolor seed extracts are good cytoplasmic dyes when used as counterstain for haematoxylin.

•

At acidic pH (3.5), Allium cepa skin extract stains cytoplasm and shows comparable result to eosin application.

•

Similarly, at a pH of 7.0, crude extract from Sorghum bicolor seed stains the cytoplasm with clear cellular features.

•

These extracts can serve as non-toxic and eco-friendly natural dyes for the demonstration of cellular and tissue morphology.

Optical detection of the potential for tooth discoloration from children's beverages by quantitative light-induced fluorescence technology

BACKGROUND

Some beverages are known to cause extrinsic staining on the tooth. This study investigated the degree of pigmentation caused by children's acidic beverages, and to confirm the possibility of the quantitative light-induced fluorescence (QLF) technology in assessing staining of the tooth.

METHODS

Bovine tooth specimens were subjected to an 8-day pH-cycling model, using six children's beverages (experimental groups) and a cola (control group), and a remineralizing solution. Before and after the pH-cycling, white-light and fluorescence images of the enamel surface were photographed with a QLF to evaluate color change (ΔE_after) and fluorescence loss (ΔF_after), respectively. Paired t-test was used to compare the tooth colors obtained before and after the pH-cycling. Spearman correlation analysis was performed to examine the correlation between the ΔE_after and ΔF_after values.

RESULTS

Median ΔE_after values of all the beverages ranged from 1.33 to 20.42, showing the greatest value in Koal-Koal Koala™ (KKK, p < 0.001). The ΔE_after was correlated with ΔF_after value negatively (ρ=-0.611, p < 0.001). The median ΔF_after varied by beverages (-38.86-0.00) and KKK caused the greatest value.

CONCLUSIONS

The cola and 6 children's beverages showed the possibility for discoloration on the tooth. The QLF technology may enable monitoring the discoloration induced on the tooth surface by acidic beverage.

Efficiency of tooth bleaching agent on staining and discoloration characteristics of nicotine stained dental enamel model

Background

Surface staining and deeper discoloration characteristics of peroxide-based bleaching agents in the nicotine stain in dental enamel model were evaluated in the present study.

Methods

Nicotine stained dental enamel fragments (n = 36) were prepared and were subjected to the bleaching ingredients for a fixed treatment time of 30 min. The bleaching agents were composed of limonene, coconut diethanolamide, and carbamide peroxide served as solvent, nonionic surfactant, and oxidizer, respectively. Optical analysis was carried out considering color stability via colorimeter and UV-Vis spectrometer.

Results

Degrees of color variations were significantly influenced by nicotine content and bleaching ingredient factors. They varied in the range of approximately 3.00 and 5.00 units for all tooth-bleaching agents. The most prominent degrees of color variation elevations were obtained in the tooth bleaching formulae set #2 (1.0% limonene + 20% coconut diethanolamide) in the stained tooth model in comparison to set #1 (0.5% limonene + 10% coconut diethanolamide) and set #3 (1.5% limonene + 30% coconut diethanolamide), partly due to the perceptible color changes. The lowest degree of color variation under a dose limitation was found in the tooth bleaching formulae set #2 + 10% carbamide peroxide formulation. Absorbance spectra were also evaluated after the interaction of bleaching treatment. They confirmed a relationship between nicotine content and discoloration characteristics of the tooth bleaching formulae set #2 + 10% carbamide peroxide.

Conclusions

Carbamide peroxide is considered as generator of free radicals. It converts the color of stains to clear by oxidizing the organic compounds in the stained dental enamel model, achieving whiteness enhancement.

Effects of stabilized stannous fluoride dentifrice on dental calculus, dental plaque, gingivitis, halitosis and stain: A systematic review

Objectives

The aim of the present systematic review was to examine the scientific evidence for the efficacy of stabilized stannous fluoride (SnF₂) dentifrice in relation to dental calculus, dental plaque, gingivitis, halitosis and staining.

Data and sources

Medline OVID, Embase.com, and the Cochrane Library were searched from database inception until June 2017. Six researchers independently selected studies, extracted data, and assessed methodological quality. A meta-analysis of the 6-month gingivitis studies was done. Risk of bias was estimated using a checklist from the Swedish Agency for Health Technology Assessment (SBU, 2018).

Study selection

Two studies on dental calculus, 21 on dental plaque and gingivitis, 4 on halitosis, and 5 on stain met the inclusion criteria. Risk of bias was high for the studies on dental calculus, halitosis, and stain, and varied for the dental plaque and gingivitis studies. Significant reductions in dental calculus and in halitosis were reported for the SnF₂ dentifrice; no differences in stain reduction were noted. A meta-analysis on gingivitis found better results for the SnF₂ dentifrice compared to other dentifrices, though the results of the individual trials in the meta-analyses showed a substantial heterogeneity.

Conclusions

The present review found that stabilized SnF₂ toothpaste had a positive effect on the reduction of dental calculus build-up, dental plaque, gingivitis, stain and halitosis. A tendency towards a more pronounced effect than using toothpastes not containing SnF2 was found. However, a new generation of well conducted randomized trials are needed to further support these findings.

Clinical relevance

Adding a SnF₂ toothpaste to the daily oral care routine is an easy strategy that may have multiple oral health benefits.

Efficacy of Three Toothpastes in Iron Stain Removal from Primary Teeth

Aim

This study aimed to assess the iron stain removal efficacy of three toothpastes in extracted primary teeth.

Materials and methods

In this in vitro study, 60 extracted sound primary teeth were selected, decoronated at the cementoenamel junction, and their pulp chambers were filled with a composite. The teeth were then immersed in ferrous sulfate solution and brushed 3,000 times in an automatic tooth-brushing machine using Colgate, whitening Crest, and conventional Crest dentifrices. Stain removal was done in four groups using a prophylaxis paste. Digital images were obtained from the teeth before and after brushing with dentifrices and the changes in color parameters were measured using Photoshop and iColor software programs. Changes in color parameters were statistically analyzed using one-way ANOVA while multiple comparisons were done by Tukey's test.

Results

The greatest change in chroma was observed in the prophylaxis group and then in the whitening Crest, Colgate, and conventional Crest (mean values of −65.2, −31.07, −21.27, and −0.73, respectively). Prophylaxis completely removed the stains. The greatest reduction in value occurred in conventional Crest, Colgate, and whitening Crest (−18.07, −12.23, and −0.4, respectively). In the L*a*b* system, the least reductions were noted in the whitening Crest, Colgate, and conventional Crest (mean values of −1.96, −3.92, and −3.37, respectively). Prophylaxis significantly improved tooth brightness (a mean increase of 4.26).

Conclusion

None of the toothpastes in this study were capable of effectively removing iron stains. Crest whitening toothpaste was slightly effective in this regard.

Clinical significance

Iron drops are routinely prescribed for children younger than 2 years of age to prevent iron deficiency and iron deficiency anemia. However, iron stains on teeth are a common concern for many parents. Finding toothpastes with greater efficacy for iron stain removal can help in this respect.

How to cite this article

Heidari A, Shahrabi M, et al. Efficacy of Three Toothpastes in Iron Stain Removal from Primary Teeth. Int J Clin Pediatr Dent 2019;12(1):10–14.

Finally an evidence-based indication for injectable phloroglucinol!

BACKGROUND

While phloroglucinol is widely prescribed in European countries for its antispasmodic properties, recent high quality data failed to demonstrate its superiority to placebo in alleviating abdominal pain. Rumors suggest that injectable presentation of phloroglucinol may erase povidone-iodine stains. We thus aimed to evaluate its efficacy in this new indication.

METHODS

In this double-blind, controlled trial, we randomly assigned 9 squares of fabric obtained from common white coat to receive injectable phloroglucinol (experimental arm), stain remover (active control arm) or water (placebo arm). The primary efficacy endpoint was the change in stain intensity 10 min after the intervention.

RESULTS

In placebo and active control arms, povidone-iodine stains remained unchanged 10 min after treatment application. In contrast, the stain disappeared completely in the experimental arm.

CONCLUSION

Injectable phloroglucinol was more effective than usual stain remover and water to remove povidone-iodine stains from white coats.

Review and analysis of grading scales for ocular surface staining

Vital dye staining has been used for over a century to assess the severity of ocular surface disease. However, despite common usage, a universally accepted "gold standard" grading scale does not exist for corneal and conjunctival staining, which can impact the ability to diagnose and monitor ocular surface conditions such as dry eye. The Food and Drug Administration (FDA) and other international regulatory agencies rely on ocular surface staining as a primary endpoint for new drug approvals, so that absence of a "gold standard" scale may affect approval of new drug treatments. To begin to address this problem, we review existing, published grading scales in an integrated fashion, highlighting their differences and similarities to emphasize common themes and the methods and elements that are important in creating a standardized scale. Our goal is to aid the field in moving towards an accepted standardized grading scale for ocular surface staining that can be applied in clinic and research settings for a variety of ocular conditions.

Effective cellulose nanocrystal imaging using transmission electron microscopy

Characterization of cellulose nanocrystals (CNCs) is often complex and tedious. With their increased use for biological materials, polymer reinforcing agents, and other applications, better characterization methods of CNCs are needed to ensure product quality. However, because of their small size, hydrogen bonding, and low electron density, individual CNCs are difficult to image with high resolution and magnification using electron microscopy. Methods to help counter these challenges include staining for increased contrast and techniques to increase dispersion. This work tested several stains, dispersing agents, and sample supports to find a consistent method of individualizing CNCs and providing good contrast for imaging in transmission electron microscopy (TEM). The most consistent method found uses a low concentration of CNCs, bovine serum albumin as a dispersing agent, and Nanovan^® as the contrasting stain on a silicon monoxide-coated Formvar TEM grid.

Metal stain on monolithic zirconia restoration: A case report

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.

Diagnostic guide enabling distinction between taphonomic stains and enamel hypomineralisation in an archaeological context

OBJECTIVE

Molar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown with or without surface breakdown. The possibility of finding MIH in 'ancient populations' could downplay several current aetiological hypotheses (e.g., dioxin derivatives, bisphenols, antibiotics) without excluding the possible multifactorial aspect of the anomaly. In an archaeological context, chemical elements contained in the burial ground can stain teeth yellow or brown and therefore might create a taphonomic bias. The purpose of the present study is to test a proposed diagnostic guide enabling determination of the pathological or taphonomic cause of enamel discolouration and defects that resemble MIH present on 'ancient teeth'.

DESIGN

Two sample groups including MIH discoloration (n=12 teeth) from living patients, taphonomic discoloration (n=9 teeth) and unknown discoloration (n=2 teeth) from medieval specimens were tested. Three non-destructive methods-Raman spectroscopy, X-ray micro-computed tomography and X-ray fluorescence were utilised.

RESULTS

Hypomineralised enamel has decreased mineral density (p<0.0001) and increased phosphate/β-carbonate ratio (p<0.01) compared to normal enamel whereas relative concentrations of manganese, copper, iron and lead are similar. In taphonomic discoloration, relative concentrations of these elements are significantly different (p<0.05) to normal enamel whereas mineral density and Raman spectra profile are comparable.

CONCLUSIONS

Enamel hypomineralisation can be distinguished from taphonomic staining in archaeological teeth.

A randomised clinical trial to evaluate the effect of a 67 % sodium bicarbonate-containing dentifrice on 0.2 % chlorhexidine digluconate mouthwash tooth staining

Background

Gingivitis can develop as a reaction to dental plaque. It can be limited by curtailing plaque build-up through actions including tooth brushing and the use of medicinal mouthwashes, such as those containing chlorhexidine digluconate (CHX), that can reach parts of the mouth that may be missed when brushing. This study aimed to compare dental stain control of twice-daily brushing with a sodium fluoride (NaF) dentifrice containing 67 % sodium bicarbonate (NaHCO₃) or a commercially available NaF silica dentifrice without NaHCO_3, while using a mouthwash containing 0.2 % CHX.

Methods

This was a 6-week, randomised, two-site, examiner-blind, parallel-group study in healthy subjects with at least ‘mild’ stain levels on the facial surfaces of ≥4 teeth and ≥15 bleeding sites. Assessment was via modified Lobene Stain Index (MLSI), the score being the mean of stain intensity multiplied by area (MLSI [IxA]).

Results

One hundred and fifty of 160 randomised subjects completed the study. There were no significant differences in Overall (facial and lingual) MLSI (IxA) scores between dentifrices. The Facial MLSI (IxA) was statistically significant at 6 weeks, favouring the 67 % NaHCO₃ dentifrice (p = 0.0404). Post-hoc analysis, conducted due to a significant site interaction, found significant differences for all MLSI scores in favour of the 67 % NaHCO₃ dentifrice at Site 1 (both weeks) but not Site 2.

Conclusions

No overall significant differences were found between a 67 and 0 % NaHCO₃ dentifrice in controlling CHX stain; a significant difference on facial surfaces suggests advantage of the former on more accessible surfaces.

Trial registration

This study was registered at ClinicalTrials.gov (NCT01962493) on 10 October 2013 and was funded by GSK Consumer Healthcare.

[Technical recommendations and best practice guidelines for May-Grünwald-Giemsa staining: literature review and insights from the quality assurance]

May-Grünwald-Giemsa (MGG) stain is a Romanowsky-type, polychromatic stain as those of Giemsa, Leishman and Wright. Apart being the reference method of haematology, it has become a routine stain of diagnostic cytopathology for the study of air-dried preparations (lymph node imprints, centrifuged body fluids and fine needle aspirations). In the context of their actions of promoting the principles of quality assurance in cytopathology, the French Association for Quality Assurance in Anatomic and Cytologic Pathology (AFAQAP) and the French Society of Clinical Cytology (SFCC) conducted a proficiency test on MGG stain in 2013. Results from the test, together with the review of literature data allow pre-analytical and analytical steps of MGG stain to be updated. Recommendations include rapid air-drying of cell preparations/imprints, fixation using either methanol or May-Grünwald alone for 3-10minutes, two-step staining: 50% May-Grünwald in buffer pH 6.8 v/v for 3-5minutes, followed by 10% buffered Giemsa solution for 10-30minutes, and running water for 1-3minutes. Quality evaluation must be performed on red blood cells (RBCs) and leukocytes, not on tumour cells. Under correct pH conditions, RBCs must appear pink-orange (acidophilic) or buff-coloured, neither green nor blue. Leukocyte cytoplasm must be almost transparent, with clearly delineated granules. However, staining may vary somewhat and testing is recommended for automated methods (slide stainers) which remain the standard for reproducibility. Though MGG stain remains the reference stain, Diff-Quik(®) stain can be used for the rapid evaluation of cell samples.

Improving acid-fast fluorescent staining for the detection of mycobacteria using a new nucleic acid staining approach

Acid fast staining of sputum smears by microscopy remains the prevalent method for detecting Mycobacterium tuberculosis. The sensitivity of microscopy using acid fast stains requires 10(4) bacilli per ml of sputum. Although fluorescent acid fast stains, such as Auramine-O, show improved sensitivity, almost half of culture-positive TB cases are currently estimated to remain smear-negative. These current diagnosis problems provide impetus for improving staining procedures. We evaluated a novel fluorescent acid-fast staining approach using the nucleic acid-binding dye SYBR(®) Gold on mycobacterial in vitro cultures. The SYBR(®) Gold stain detected 99% of MTB in both actively replicating aerobic and non-replicating hypoxic cultures. Transmission light microscopy with Ziehl-Neelsen fuchsin, and fluorescence microscopy with Auramine-O or Auramine-rhodamine detected only 54%-86% of MTB bacilli. SYBR(®) Gold fluoresces more intensely than Auramine-O, and is highly resistant to fading. The signal to noise ratio is exceptionally high due to a >1000-fold enhanced fluorescence after binding to DNA/RNA, thereby reducing most background fluorescence. Although cost and stability of the dye may perhaps limit its clinical use at this time, these results warrant further research into more nucleic acid dye variants. In the meantime, SYBR(®) Gold staining shows great promise for use in numerous research applications.

Improved staining of phosphoproteins with high sensitivity in polyacrylamide gels using Stains-All

An improved Stains-All (ISA) staining method for phosphoproteins in SDS-PAGE was described. Down to 0.5-1 ng phosphoproteins (α-casein, β-casein, or phosvitin) can be successfully selectively detected by ISA stain, which is approximately 120-fold higher than that of original Stains-All stain, but is similar to that of commonly used Pro-Q Diamond stain. Furthermore, unlike the original Stains-All protocol that was time consuming and light unstable, ISA stain could be completed within 60 min without resorting to protect the gels from light during the whole staining procedure. According to the results, it is concluded that ISA stain is a rapid, sensitive, specific, and economic staining method for a broad application to the research of phosphoproteins.