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Fulltext Measuring pH of the Plasmodium falciparum digestive vacuole by flow cytometry

Abu Bakar N

Trop Biomed, 2015 Sep;32(3):485-93.
PMID: 26695209 MyJurnal

Studies show that the pH of the malaria parasite's digestive vacuole (DV) plays a key role in the physiological functions of this organelle and antimalarial drug accumulation, and yet is technically difficult to measure. In this study, a flow cytometry-based technique was developed to measure the DV pH using a ratiometric pH indicator, FITC-dextran loaded into the DV of saponin-permeabilized parasites. To calculate the DV pH, a standard pH calibration curve was generated by incubating the saponin-permeabilized cells in buffers with different pH in the presence of an ionophore, CCCP. The measured average pH of the DV was 5.27 ± 0.03 that is approximately the same in the parasites observed microscopically by Hayward et al. (2006) (5.50 ± 0.14) using the same probe. The removal of glucose from the medium, causing a rapid depletion of parasite ATP, resulted in an alkalization of the DV. The DV was reacidified upon restoration of glucose to the medium. This technique provides a rapid, simple and quantitative measurement of the DV pH on a large number of cells. It will also be useful in future attempts to evaluate the effect of antimalarial drugs (i.e. chloroquine and artemisinin-based drugs) in pH changes of the DV.

Matched MeSH terms: Staining and Labeling/methods
Detection of influenza A and B neutralizing antibodies in vaccinated ferrets and macaques using specific biotin-streptavidin conjugated antibodies

Sirskyj D, Weltzin R, Golshani A, Anderson D, Bozic J, Diaz-Mitoma F, et al.

J Virol Methods, 2010 Feb;163(2):459-64.
PMID: 19913054 DOI: 10.1016/j.jviromet.2009.11.014

Several critical factors of an influenza microneutralization assay, utilizing a rapid biotin-streptavidin conjugated system for detecting influenza virus subtypes A and B, are addressed within this manuscript. Factors such as incubation times, amount of virus, cell seeding, sonication, and TPCK trypsin were evaluated for their ability to affect influenza virus neutralization in a microplate-based neutralization assay using Madin-Darby canine kidney (MDCK) cells. It is apparent that the amount of virus used in the assay is the most critical factor to be optimized in an influenza microneutralization assay. Results indicate that 100xTCID(50) of influenza A/Solomon Islands/03/2006 (H1N1) virus overloads the assay and results in no, to low, neutralization, in both ferret and macaque sera, respectively, whereas using 6xTCID(50) resulted in significantly improved neutralization. Conversely, strong neutralization was observed against 100xTCID(50) of B/Malaysia/2506/04 virus. In this manuscript the critical factors described above were optimized and the results indicate that the described biotin-streptavidin conjugated influenza microneutralization assay is a rapid and robust method for detecting the presence of functional, influenza virus-neutralizing antibodies.

Matched MeSH terms: Staining and Labeling/methods
Prevalence of microsporidia in an indigenous Orang Asli community in Pahang, Malaysia

Lono A, Kumar GS, Chye TT

Trans R Soc Trop Med Hyg, 2010 Mar;104(3):214-8.
PMID: 19716577 DOI: 10.1016/j.trstmh.2009.07.006

Microsporidia are ubiquitous parasites thought to be closely related to fungi. Their presence in the environment means that humans are frequently exposed to infection. Stool samples were collected from 151 indigenous villagers from the eastern state of Pahang in 2005. The samples were concentrated with water-ether sedimentation, stained with modified trichrome stain and examined under oil-immersion microscopy. Thirty-two specimens (21.2%) were positive for microsporidia. Microsporidia were observed as ovoid or rounded ovoid shapes measuring approximately 1mum, with a bright pink outline containing a central or posterior vacuole. PCR amplification with specific primers on microscopy-positive specimens amplified Encephalitozoon intestinalis DNA from five of the ten specimens used.

Matched MeSH terms: Staining and Labeling/methods
Modified fields' stain: ideal to differentiate Dientamoeba fragilis and Blastocystis sp

Ragavan AD, Govind SK

Parasitol Res, 2015 Mar;114(3):1163-6.
PMID: 25614298 DOI: 10.1007/s00436-014-4296-8

Dientamoeba fragilis, a trichomonad parasite is usually found in the gastrointestinal tract of human, and it is known to be the cause for gastrointestinal disease. The parasite is globally distributed and mostly found in rural and urban areas. The parasite is found in humans and nonhuman primates such as the macaques, baboons, and gorillas. Often, the parasite is confused with another largely found organism in stools called Blastocystis sp. especially when seen directly under light microscopy on culture samples containing both parasites. Both sometimes are seen with two nuclei with sizes tending to be similar which complicates identification. Stools were collected fresh from nine previously diagnosed persons infected with D. fragilis who also were found to be positive for Blastocystis sp. Samples were then cultured in Loeffler's medium and were stained with Giemsa, iron hematoxylin, and modified Fields' (MF) stain, respectively. D. fragilis was differentiated from Blastocystis sp. when stained with MF stain by the presence of a thinner outer membrane with clearly demarcated nuclei in the center of the cell whilst Blastocystis sp. had a darker and thicker stained outer membrane with the presence of two nuclei. The staining contrast was more evident with modified Fields' stain when compared with the other two. The simplicity in preparing the stain as well as the speed of the staining procedure make MF stain an ideal alternate. The modified Fields' stain is faster and easier to prepare when compared to the other two stains. MF stain provides a better contrast differentiating the two organisms and therefore provides a more reliable diagnostic method to precisely identify one from the other especially when cultures show mixed infections.

Matched MeSH terms: Staining and Labeling/methods*
Fulltext Computer-assisted quantification of CD3+ T cells in follicular lymphoma

Abas FS, Shana'ah A, Christian B, Hasserjian R, Louissaint A, Pennell M, et al.

Cytometry A, 2017 06;91(6):609-621.
PMID: 28110507 DOI: 10.1002/cyto.a.23049

The advance of high resolution digital scans of pathology slides allowed development of computer based image analysis algorithms that may help pathologists in IHC stains quantification. While very promising, these methods require further refinement before they are implemented in routine clinical setting. Particularly critical is to evaluate algorithm performance in a setting similar to current clinical practice. In this article, we present a pilot study that evaluates the use of a computerized cell quantification method in the clinical estimation of CD3 positive (CD3+) T cells in follicular lymphoma (FL). Our goal is to demonstrate the degree to which computerized quantification is comparable to the practice of estimation by a panel of expert pathologists. The computerized quantification method uses entropy based histogram thresholding to separate brown (CD3+) and blue (CD3-) regions after a color space transformation. A panel of four board-certified hematopathologists evaluated a database of 20 FL images using two different reading methods: visual estimation and manual marking of each CD3+ cell in the images. These image data and the readings provided a reference standard and the range of variability among readers. Sensitivity and specificity measures of the computer's segmentation of CD3+ and CD- T cell are recorded. For all four pathologists, mean sensitivity and specificity measures are 90.97 and 88.38%, respectively. The computerized quantification method agrees more with the manual cell marking as compared to the visual estimations. Statistical comparison between the computerized quantification method and the pathologist readings demonstrated good agreement with correlation coefficient values of 0.81 and 0.96 in terms of Lin's concordance correlation and Spearman's correlation coefficient, respectively. These values are higher than most of those calculated among the pathologists. In the future, the computerized quantification method may be used to investigate the relationship between the overall architectural pattern (i.e., interfollicular vs. follicular) and outcome measures (e.g., overall survival, and time to treatment). © 2017 International Society for Advancement of Cytometry.

Matched MeSH terms: Staining and Labeling/methods
Detection and differentiation of velogenic and lentogenic Newcastle disease viruses using SYBR Green I real-time PCR with nucleocapsid gene-specific primers

Tan SW, Ideris A, Omar AR, Yusoff K, Hair-Bejo M

J Virol Methods, 2009 Sep;160(1-2):149-56.
PMID: 19447142 DOI: 10.1016/j.jviromet.2009.05.006

SYBR Green I real-time PCR was developed for detection and differentiation of Newcastle disease virus (NDV). Primers based on the nucleocapsid (NP) gene were designed to detect specific sequence of velogenic strains and lentogenic/vaccine strains, respectively. The assay was developed and tested with NDV strains which were characterized previously. The velogenic strains were detected only by using velogenic-specific primers with a threshold cycle (C(t)) 18.19+/-3.63 and a melting temperature (T(m)) 86.0+/-0.28 degrees C. All the lentogenic/vaccine strains, in contrast, were detected only when lentogenic-specific primers were used, with the C(t) value 14.70+/-2.32 and T(m) 87.4+/-0.21 degrees C. The assay had a dynamic detection range which spans over a 5log(10) concentration range, 10(9)-10(5) copies of DNA plasmid/reaction. The velogenic and lentogenic amplifications showed high PCR efficiency of 100% and 104%, respectively. The velogenic and lentogenic amplifications were highly reproducible with assay variability 0.45+/-0.31% and 1.30+/-0.65%, respectively. The SYBR Green I real-time PCR assay detected successfully the virus from tissue samples and oral swabs collected from the velogenic and lentogenic NDV experimental infection, respectively. In addition, the assay detected and differentiated accurately NDV pathotypes from suspected field samples where the results were in good agreement with both virus isolation and analysis of the fusion (F) cleavage site sequence. The assay offers an attractive alternative method for the diagnosis of NDV.

Matched MeSH terms: Staining and Labeling/methods
Expression of multidrug resistance (MDR) proteins and in vitro drug resistance in acute leukemias

Fazlina N, Maha A, Jamal R, Zarina AL, Cheong SK, Hamidah H, et al.

Hematology, 2007 Feb;12(1):33-7.
PMID: 17364990

The expression of the multidrug resistance (MDR) proteins may influence the outcome of treatment in patients with acute leukemia. The aim of this study was to determine the IC50 of cytotoxic drugs (cytosine arabinoside, ara-C and daunorubicin, dnr) using the in vitro 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)2H-tetrazolium, inner salt (MTS) assay method. A total of 82 newly diagnosed acute leukemia cases (43 adult myeloid leukaemia, AML cases and 39 acute lymphoblastic leukaemia, ALL cases) and 16 relapsed cases (8 AML cases and 8 ALL cases) were studied. The MTS assay was performed using two cytotoxic drugs, dnr and ara-C. Cells were incubated with different concentrations of drugs for 4 days and the IC50 was extrapolated from the viability curve. In newly diagnosed cases, we found that childhood ALL samples showed higher IC50 values of dnr (0.040 +/- 2.320) compared to adult AML samples (0.021 +/- 0.158). In contrast, newly diagnosed adult AML samples showed higher IC50 values of ara-C (0.157 +/- 0.529) compared to childhood ALL samples (0.100 +/- 2.350). In relapsed cases, two samples of childhood ALL showed IC50 values of dnr (0.910 +/- 1.760) and ara-C (1.310 +/- 2.390), which was higher compared to childhood AML samples (0.129 +/- 0.214 and 0.210 +/- 0.003, respectively). However, there was no correlation between IC50 values of these drugs tested with clinical outcome. In conclusion, we found that MTS assay is an easy, rapid and non laborious method to study in vitro drug resistance in acute leukaemia cases.

Matched MeSH terms: Staining and Labeling/methods
Fulltext Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods

Ning TZ, Kin WW, Mustafa S, Ahmed A, Noordin R, Cheong TG, et al.

Asian Pac J Trop Biomed, 2012 Jan;2(1):61-5.
PMID: 23569836 DOI: 10.1016/S2221-1691(11)60191-3

To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster.

Matched MeSH terms: Staining and Labeling/methods*
Comparative analysis between multilevel sectioning with conventional haematoxylin and eosin staining and immunohistochemistry for detecting nodal micrometastases with stage I and II colorectal cancers

Wong YP, Shah SA, Shaari N, Mohamad Esa MS, Sagap I, Isa NM

Asian Pac J Cancer Prev, 2014;15(4):1725-30.
PMID: 24641399

Management of patients with stage II colorectal carcinomas remains challenging as 20 - 30% of them will develop recurrence. It is postulated that these patients may harbour nodal micrometastases which are imperceptible by routine histopathological evaluation. The aims of our study were to evaluate (1) the feasibility of multilevel sectioning method utilizing haematoxylin and eosin stain and immunohistochemistry technique with cytokeratin AE1/AE3, in detecting micrometastases in histologically-negative lymph nodes, and (2) correlation between nodal micrometastases with clinicopathological parameters. Sixty two stage I and II cases with a total of 635 lymph nodes were reviewed. Five-level haematoxylin and eosin staining and one-level cytokeratin AE1/AE3 immunostaining were performed on all lymph nodes retrieved. The findings were correlated with clinicopathological parameters. Two (3.2%) lymph nodes in two patients (one in each) were found to harbour micrometastases detected by both methods. With cytokeratin AE1/AE3, we successfully identified four (6.5%) patients with isolated tumour cells, but none through the multilevel sectioning method. Nodal micrometastases detected by both multilevel sectioning and immunohistochemistry methods were not associated with larger tumour size, higher depth of invasion, poorer tumour grade, disease recurrence or distant metastasis. We conclude that there is no difference between the two methods in detecting nodal micrometastases. Therefore it is opined that multilevel sectioning is a feasible and yet inexpensive method that may be incorporated into routine practice to detect nodal micrometastases in centres with limited resources.

Matched MeSH terms: Staining and Labeling/methods*
Fulltext Antiproliferative property and apoptotic effect of xanthorrhizol on MDA-MB-231 breast cancer cells

Cheah YH, Nordin FJ, Tee TT, Azimahtol HL, Abdullah NR, Ismail Z

Anticancer Res, 2008 Nov-Dec;28(6A):3677-89.
PMID: 19189649

Xanthorrhizol is a natural sesquiterpenoid compound isolated from the rhizome of Curcuma xanthorrhizza Roxb (Zingerberaceae). Recent studies of xanthorrhizol in cell cultures strongly support the role of xanthorrhizol as an antiproliferative agent. In our study, we tested the antiproliferative effect of xanthorrhizol using different breast cancer cell lines. The invasive breast cancer cell line, MDA-MB-231, was then selected for further investigations. Treatment with xanthorrhizol caused 50% growth inhibition on MDA-MB-231 cells at 8.67 +/- 0.79 microg/ml as determined by sulforhodamine B (SRB) assay. Hoechst 33258 nuclear staining assay showed the rate of apoptosis of MDA-MB-231 cells to increase in response to xanthorrhizol treatment. Immunofluorescence staining using antibody MitoCapture and fluorescein isothiocyanate (FITC)-labeled cytochrome c revealed the possibility of altered mitochondrial transmembrane potential and the release of cytochrome c respectively. This was further confirmed by Western-blotting, where cytochrome c was showed to migrate from mitochondrial fraction to the cytosol fraction of treated MDA-MB-231 cells. Caspase activity assay showed the involvement of caspase-3 and caspase-9, but not caspase-6 or caspase-8 in MDA-MB-231 apoptotic cell death. Subsequently, cleavage of PARP-1 protein is suggested. These data suggest treatment with xanthorrhizol modulates MDA-MB-231 cell apoptosis through the mitochondria-mediated pathway subsequent to the disruption of mitochondrial transmembrane potential, release of cytochrome c, activation of caspase-3 and caspase-9, and the modulation of PARP-1 protein.

Matched MeSH terms: Staining and Labeling/methods
Fulltext Improvement of malaria diagnostic system based on acridine orange staining

Kimura M, Teramoto I, Chan CW, Idris ZM, Kongere J, Kagaya W, et al.

Malar J, 2018 Feb 07;17(1):72.
PMID: 29415724 DOI: 10.1186/s12936-018-2214-8

BACKGROUND: Rapid diagnosis of malaria using acridine orange (AO) staining and a light microscope with a halogen lamp and interference filter was deployed in some malaria-endemic countries. However, it has not been widely adopted because: (1) the lamp was weak as an excitation light and the set-up did not work well under unstable power supply; and, (2) the staining of samples was frequently inconsistent.
METHODS: The halogen lamp was replaced by a low-cost, blue light-emitting diode (LED) lamp. Using a reformulated AO solution, the staining protocol was revised to make use of a concentration gradient instead of uniform staining. To evaluate this new AO diagnostic system, a pilot field study was conducted in the Lake Victoria basin in Kenya.
RESULTS: Without staining failure, malaria infection status of about 100 samples was determined on-site per one microscopist per day, using the improved AO diagnostic system. The improved AO diagnosis had both higher overall sensitivity (46.1 vs 38.9%: p = 0.08) and specificity (99.0 vs 96.3%) than the Giemsa method (N = 1018), using PCR diagnosis as the standard.
CONCLUSIONS: Consistent AO staining of thin blood films and rapid evaluation of malaria parasitaemia with the revised protocol produced superior results relative to the Giemsa method. This AO diagnostic system can be set up easily at low cost using an ordinary light microscope. It may supplement rapid diagnostic tests currently used in clinical settings in malaria-endemic countries, and may be considered as an inexpensive tool for case surveillance in malaria-eliminating countries.

Matched MeSH terms: Staining and Labeling/methods*
Fulltext A P. falciparum NF54 Reporter Line Expressing mCherry-Luciferase in Gametocytes, Sporozoites, and Liver-Stages

Marin-Mogollon C, Salman AM, Koolen KMJ, Bolscher JM, van Pul FJA, Miyazaki S, et al.

Front Cell Infect Microbiol, 2019;9:96.
PMID: 31058097 DOI: 10.3389/fcimb.2019.00096

Transgenic malaria parasites expressing fluorescent and bioluminescent proteins are valuable tools to interrogate malaria-parasite biology and to evaluate drugs and vaccines. Using CRISPR/Cas9 methodology a transgenic Plasmodium falciparum (Pf) NF54 line was generated that expresses a fusion of mCherry and luciferase genes under the control of the Pf etramp10.3 gene promoter (line mCherry-luc@etramp10.3). Pf etramp10.3 is related to rodent Plasmodium uis4 and the uis4 promoter has been used to drive high transgene expression in rodent parasite sporozoites and liver-stages. We examined transgene expression throughout the complete life cycle and compared this expression to transgenic lines expressing mCherry-luciferase and GFP-luciferase under control of the constitutive gapdh and eef1a promoters. The mCherry-luc@etramp10.3 parasites express mCherry in gametocytes, sporozoites, and liver-stages. While no mCherry signal was detected in asexual blood-stage parasites above background levels, luciferase expression was detected in asexual blood-stages, as well as in gametocytes, sporozoites and liver-stages, with the highest levels of reporter expression detected in stage III-V gametocytes and in sporozoites. The expression of mCherry and luciferase in gametocytes and sporozoites makes this transgenic parasite line suitable to use in in vitro assays that examine the effect of transmission blocking inhibitors and to analyse gametocyte and sporozoite biology.

Matched MeSH terms: Staining and Labeling/methods*
Modified Field's staining--a rapid stain for Trichomonas vaginalis

Afzan MY, Sivanandam S, Kumar GS

Diagn Microbiol Infect Dis, 2010 Oct;68(2):159-62.
PMID: 20846588 DOI: 10.1016/j.diagmicrobio.2010.06.005

Trichomonas vaginalis, a flagellate protozoan parasite commonly found in the human genitourinary tract, is transmitted primarily by sexual intercourse. Diagnosis is usually by in vitro culture method and staining with Giemsa stain. There are laboratories that use Gram stain as well. We compared the use of modified Field's (MF), Giemsa, and Gram stains on 2 axenic and xenic isolates of T. vaginalis, respectively. Three smears from every sediment of spun cultures of all 4 isolates were stained, respectively, with each of the stains. We showed that MF staining, apart from being a rapid stain (20 s), confers sharper staining contrast, which differentiates the nucleus and the cytoplasm of the organism when compared to Giemsa and Gram staining especially on parasites from spiked urine samples. The alternative staining procedure offers in a diagnostic setting a rapid stain that can easily visualize the parasite with sharp contrasting characteristics between organelles especially the nucleus and cytoplasm. Vacuoles are more clearly visible in parasites stained with MF than when stained with Giemsa.

Matched MeSH terms: Staining and Labeling/methods*
Field's stain--a rapid staining method for Acanthamoeba spp

Pirehma M, Suresh K, Sivanandam S, Anuar AK, Ramakrishnan K, Kumar GS

Parasitol Res, 1999 Oct;85(10):791-3.
PMID: 10494803

Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba sp. using the modified Field's staining technique. A. castellanii, which was used in the present experiment, is maintained in our laboratory in mycological peptone medium (Gibco). The cultures were pooled together and smears were made on glass slides for staining purposes. Different types of stains such as Field's stain, modified Field's stain, Wright's stain, Giemsa stain, Ziehl-Neelsen stain, and trichrome stain were used to determine the best stain for the identification of this amoeba. The concentration of various stains and the duration of staining were varied to provide the best color and contrast for each stain. Acanthamoeba was also obtained from the brain of experimentally infected mice and was stained with various stains as mentioned above to determine the best stain for use in identifying the presence of this parasite in experimentally infected animals. The modified Field's stain gives a very good color contrast as compared with other stains. Furthermore, it takes only 20 s to be carried out using the least number of reagents, making it suitable for both laboratory and field use.

Matched MeSH terms: Staining and Labeling/methods*
Fulltext Identification of Entamoeba histolytica trophozoites in fresh stool sample: comparison of three staining techniques and study on the viability period of the trophozoites

Tan ZN, Wong WK, Nik Zairi Z, Abdullah B, Rahmah N, Zeehaida M, et al.

Trop Biomed, 2010 Apr;27(1):79-88.
PMID: 20562817 MyJurnal

Entamoeba histolytica causes about 50 million infections worldwide with a death rate of over 100,000 annually. In endemic developing countries where resources are limited, microscopic examinations based on Wheatley trichrome staining is commonly used for diagnosis of intestinal amoebiasis. Other than being a time-consuming method, it must be performed promptly after stool collection as trophozoites disintegrate rapidly in faeces. The aim of this study was to compare the efficacies of Eosin-Y, Wheatley trichrome and Iodine stains in delineating the diagnostic features of the parasite, and subsequently to determine the suitable microscopy observation period for detection of erythrophagocytic and non-erythrophagocytic trophozoites spiked in semi-solid stool sample. Wheatley trichrome staining technique was performed using the standard method while the other two techniques were performed on the slides by mixing the respective staining solution with the spiked stool sample. One million of axenically cultured non-erythrophagocytic E. histolytica and erythrophagocytic E. histolytica were separately spiked into 2 g of fresh semisolid faeces. Percentage viability of the trophozoites in the spiked stool sample was determined at 30 minute intervals for eight hours using the 0.4% Trypan blue exclusion method. The results showed that Eosin-Y and Wheatley trichrome stained the karyosome and chromatin granules better as compared to Iodine stain. The percentage viability of non-erythrophagocytic trophozoites decreased faster than the erythrophagocytic form in the first 5 hours and both dropped to ~10% in the 6th hour spiked sample. In conclusion, Eosin-Y staining technique was found to be the easiest to perform, most rapid and as accurate as the commonly used Wheatley trichrome technique; Eosin-Y stained slide sealed with DPX could also be kept as a permanent record. A period not exceeding 6 hours after stool collection was found to be the most suitable in order to obtain good microscopy results of viable trophozoites.

Matched MeSH terms: Staining and Labeling/methods*
Morphological characteristics of developmental stages of Acanthamoeba and Naegleria species before and after staining by various techniques

Ithoi I, Ahmad AF, Mak JW, Nissapatorn V, Lau YL, Mahmud R

Southeast Asian J. Trop. Med. Public Health, 2011 Nov;42(6):1327-38.
PMID: 22299400

Seven stains were studied to determine the best color and contrast for staining the developmental stages of free living pathogenic Acanthamoeba and Naegleria species. The acid-fast bacilli stain (AFB) produced a blue color without contrast; trichrome-eosin and modified Field's showed various color contrasts; Giemsa, iron-hematoxylin, modified AFB and Gram produced only one color which distinguished the nucleus, nucleolus, cytoplasm, food- and water-vacuoles. The motile organs (acanthopodia, pseudopodia, lobopodia and flagella) were also clearly differentiated but produced a similar color as the cytoplasm. These motile organelles were first induced by incubating at 37 degrees C for at least 15 minutes and then fixing with methanol in order to preserve the protruding morphology prior to staining. The trichrome-eosin and iron-hematoxylin stains showed good color contrast for detecting all three stages, the trophozoite, cyst and flagellate; Giemsa and Gram stained the trophozoite and flagellate stages; the modified Field's and modified AFB stains stained only the trophozoite stage. Depending on the purpose, all these stains (except the AFB stain) can be used to identify the developmental stages of Acanthamoeba and Naegleria for clinical, epidemiological or public health use.

Matched MeSH terms: Staining and Labeling/methods*
Comparison of the sensitivity and specificity of p16/Ki-67 dual staining and HPV DNA testing of abnormal cervical cytology in the detection of histology proven cervical intraepithelial neoplasia grade 2 and above (CIN 2+)

Tay TKY, Lim KL, Hilmy MH, Thike AA, Goh ST, Song LH, et al.

Malays J Pathol, 2017 Dec;39(3):257-265.
PMID: 29279588

INTRODUCTION: Human papillomavirus (HPV) testing is used as a means of triaging cervico-vaginal smears with low grade squamous abnormalities or as part of co-testing with cytology. While HPV testing has a high sensitivity, it has a low specificity in detecting cervical intraepithelial neoplasia grade 2 and above (CIN 2+) leading to unnecessary colposcopy referrals. We investigate the accuracy of the p16/Ki-67 dual immunocytochemical stain in determining the presence of CIN 2+ lesions on histology and its potential as a superior biomarker for triage.
METHODS: Liquid based cervico-vaginal cytology specimens with squamous abnormalities and corresponding histology from 97 women with subsequent colposcopy and biopsy were included. The specimens were then subjected to the dual stain and Roche Cobas 4800 multiplex real time PCR HPV DNA testing. The sensitivity and specificity of the dual stain and HPV testing were calculated using CIN 2+ on histology as a reference standard.
RESULTS: The sensitivity and specificity of the dual stain in detecting histology proven CIN 2+ was 93.7% and 76.5% while HPV testing was 85.7% and 14.7% respectively. Of the 44 women with ASCUS or LSIL on cytology, the dual stain also reduced the number of unnecessary colposcopy referrals from 27 to 7 when used as a triage marker compared to HPV testing.
CONCLUSION: p16/Ki-67 dual stain was more sensitive and specific than HPV testing in determining the presence of CIN 2+ on histology. It could triage low grade cervico-vaginal specimens more effectively and potentially help women avoid unnecessary colposcopies. Future studies are needed to further evaluate its role in cervical cancer screening programmes.

Matched MeSH terms: Staining and Labeling/methods
Wintergreen oil: a novel method in Wheatley's trichrome staining technique

Salleh FM, Anuar TS, Yasin AM, Moktar N

J Microbiol Methods, 2012 Oct;91(1):174-8.
PMID: 22986100 DOI: 10.1016/j.mimet.2012.08.004

Permanent staining of faecal smears by Wheatley's trichrome technique has been used by many scientists for the detection of parasites in the past and it was found to be highly sensitive. This study was conducted to evaluate the use of Wintergreen oil in comparison with xylene in Wheatley's trichrome staining technique, as the reference technique. In a blind comparison study, 500 collected faecal samples from aboriginal communities were examined. Wintergreen oil was found to be more superior than xylene as a clearing agent in the Wheatley's trichrome staining of polyvinyl alcohol-fixed faecal smears for the identification of intestinal protozoa. Elimination of toxic, carcinogenic, and fire hazards makes Wintergreen oil the preferred choice in routine parasitology examinations.

Matched MeSH terms: Staining and Labeling/methods*
Evaluation of gram-chromotrope kinyoun staining technique: its effectiveness in detecting microsporidial spores in fecal specimens

Salleh FM, Al-Mekhlafi AM, Nordin A, Yasin 'M, Al-Mekhlafi HM, Moktar N

Diagn Microbiol Infect Dis, 2011 Jan;69(1):82-5.
PMID: 21146718 DOI: 10.1016/j.diagmicrobio.2010.08.028

This study was conducted to evaluate the modification of the usual Gram-chromotrope staining technique developed in-house known as Gram-chromotrope Kinyoun (GCK) in comparison with the Weber Modified Trichrome (WMT) staining technique; as the reference technique. Two hundred and ninety fecal specimens received by the Microbiology Diagnostic Laboratory of Hospital Universiti Kebangsaan Malaysia were examined for the presence of microsporidial spores. The sensitivity and specificity of GCK compared to the reference technique were 98% and 98.3%, respectively. The positive and negative predictive values were 92.5% and 99.6%, respectively. The agreement between the reference technique and the GCK staining technique was statistically significant by Kappa statistics (K = 0.941, P < 0.001). It is concluded that the GCK staining technique has high sensitivity and specificity in the detection of microsporidial spores in fecal specimens. Hence, it is recommended to be used in the diagnosis of intestinal microsporidiosis.

Matched MeSH terms: Staining and Labeling/methods*
Evaluation of formalin-ether sedimentation and trichrome staining techniques: its effectiveness in detecting Entamoeba histolytica/dispar/moshkovskii in stool samples

Anuar TS, Al-Mekhlafi HM, Abdul Ghani MK, Abu Bakar E, Azreen SN, Salleh FM, et al.

J Microbiol Methods, 2013 Mar;92(3):344-8.
PMID: 23361047 DOI: 10.1016/j.mimet.2013.01.010

This study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round PCR assay as the reference technique to detect Entamoeba histolytica/dispar/moshkovskii. Examination was performed on 500 stool samples obtained from Orang Asli communities in different states of Malaysia using formalin-ether sedimentation, trichrome staining and single-round PCR techniques. Ninety-three stool samples were detected E. histolytica/dispar/moshkovskii positive by routine microscopy, while single-round PCR detected 106 positive samples. Additional positives detected by PCR assay were eventually confirmed to be negative by both microscopic techniques. Detection rate of E. histolytica/dispar/moshkovskii was highest in combination techniques (18.6%), followed by trichrome staining (13.4%) and formalin-ether sedimentation (11.2%) techniques. Single-round PCR detected 21.2% of the stool samples. The sensitivity and specificity of formalin-ether sedimentation and trichrome staining techniques compared to the reference technique were 31.1% (95% CI: 29.0-36.0) and 94.2% (95% CI: 89.8-98.9), and 53.8% (95% CI: 46.0-76.2) and 97.5% (95% CI: 92.8-99.1), respectively. However, the sensitivity [59.4% (95% CI: 48.9-78.5)] of the method increased when both techniques were performed together, but the specificity decreased to 92.4% (95% CI: 81.0-98.0). The agreement between the reference technique, trichrome staining and combination techniques were statistically significant by Kappa statistics (trichrome staining: K = 0.592, p < 0.05; combination techniques: K = 0.543, p < 0.05). Hence, the combination technique is recommended to be used as a screening method in the diagnosis of E. histolytica/dispar/moshkovskii infections either for clinical or epidemiological study.

Matched MeSH terms: Staining and Labeling/methods

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