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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.
Efficacy of Human Cell-Seeded Muscle-Stuffed Vein Conduit in Rat Sciatic Nerve Repair

Ramli K, Gasim AI, Ahmad AA, Htwe O, Mohamed Haflah NH, Law ZK, et al.

Tissue Eng Part A, 2019 10;25(19-20):1438-1455.
PMID: 30848172 DOI: 10.1089/ten.TEA.2018.0279

We investigated the efficacy of a muscle-stuffed vein (MSV) seeded with neural-transdifferentiated human mesenchymal stem cells as an alternative nerve conduit to repair a 15-mm sciatic nerve defect in athymic rats. Other rats received MSV conduit alone, commercial polyglycolic acid conduit (Neurotube®), reverse autograft, or were left untreated. Motor and sensory functions as well as nerve conductivity were evaluated for 12 weeks, after which the grafts were harvested for histological analyses. All rats in the treatment groups demonstrated a progressive increase in the mean Sciatic Functional Index (motor function) and nerve conduction amplitude (electrophysiological function) and showed positive withdrawal reflex (sensory function) by the 10th week of postimplantation. Autotomy, which is associated with neuropathic pain, was severe in rats treated with conduit without cells; there was mild or no autotomy in the rats of other groups. Histologically, harvested grafts from all except the untreated groups exhibited axonal regeneration with the presence of mature myelinated axons. In conclusion, treatment with MSV conduit is comparable to that of other treatment groups in supporting functional recovery following sciatic nerve injury; and the addition of cells in the conduit alleviates neuropathic pain. Impact Statement It is shown that pretreated muscle-stuffed vein conduit is comparable to that of commercial nerve conduit and autograft in supporting functional recovery following peripheral nerve injury. The addition of neural-differentiated mesenchymal stem cells in the conduit is shown to alleviate neuropathic pain.
Unusual form of superficial spreading microinvasive squamous cell carcinoma of uterine cervix involving the endometrium of uterus

Tan GC, Isa MR, Ng SP, Jamil YM

J Obstet Gynaecol Res, 2004 Oct;30(5):363-7.
PMID: 15327449

Microinvasive squamous cell carcinoma of the uterine cervix is a recognized entity and is defined as carcinoma with invasion of less than 5 mm penetration of the stroma and seldom metastasized. Our patient was a 70-year-old, multiparous woman who had a microinvasive, cervical, squamous cell carcinoma. The tumor had spread superficially into the entire endometrial cavity up to the fundus, totally replacing the columnar epithelium. This is an extremely rare phenomenon, with fewer than 20 cases reported so far in the literature.
Endocan expression in placenta of women with hypertension

Chew BS, Ghazali R, Othman H, Ismail NAM, Othman AS, Laim NMST, et al.

J Obstet Gynaecol Res, 2018 Oct 10.
PMID: 30306675 DOI: 10.1111/jog.13836

AIM: The aim of our study was to determine the endocan-1 expression in placenta of hypertensive women, and its association with maternal and fetal outcomes.
METHODS: This was a cross-sectional study consisted of 21 pregnant women with hypertension and 23 without hypertension. The gestational age ranged from 28 to 39 weeks (hypertensive) and 32 to 40 weeks (normotensive). The paraffin embedded formalin fixed placenta tissue blocks were retrieved from the pathology archives. Endocan immunohistochemistry was performed on tissue sections of full thickness and maternal surface of the placenta. The endocan expression was determined in fetal endothelial cells, maternal endothelial cells, cytotrophoblasts, syncytiotrophoblasts and decidual cells. The differences in endocan expression in placenta between hypertensive and normotensive subjects were evaluated by Pearson chi-square test and t-test were used in the statistical analysis.
RESULTS: The endocan expression was significantly higher in fetal endothelial cells (P
Fulltext Tracheal agenesis: a rare cause of unsuccessful tracheal intubation during resuscitation

Iszuari M, Mazita A, Tan GC, Hayati AR, Shareena I, Cheah FC

Med J Malaysia, 2010 Dec;65(4):317-8.
PMID: 21901957

Tracheal agenesis is a rare congenital airway anomaly that usually results in a fatal outcome. The diagnosis is usually made through post-mortem examination. In the current literature, there has been no reported long-term survival although a few reports claimed prolongation of life of several hours to days. This condition is commonly associated with premature birth, polyhydramnios and a male predominance. In 90% of the cases, it is associated with multiple cardiovascular, gastrointestinal and genitourinary tract anomalies which are incompatible with life. We report a case of a premature newborn with severe respiratory distress, absent cry and cyanosis soon after birth. Attempts at endotracheal intubation failed as it was no possible to negotiate the tube beyond the vocal cords. Needle cricothyrotomy and attempted tracheostomy also failed to secure the airway. The diagnosis was confirmed at post-mortem examination.
Fulltext Evaluation of DNA and RNA extraction methods

Edwin Shiaw CS, Shiran MS, Cheah YK, Tan GC, Sabariah AR

Med J Malaysia, 2010 Jun;65(2):133-7.
PMID: 23756798 MyJurnal

This study was done to evaluate various DNA and RNA extractions from archival FFPE tissues. A total of 30 FFPE blocks from the years of 2004 to 2006 were assessed with each modified and adapted method. Extraction protocols evaluated include the modified enzymatic extraction method (Method A), Chelex-100 extraction method (Method B), heat-induced retrieval in alkaline solution extraction method (Methods C and D) and one commercial FFPE DNA Extraction kit (Qiagen, Crawley, UK). For RNA extraction, 2 extraction protocols were evaluated including the enzymatic extraction method (Method 1), and Chelex-100 RNA extraction method (Method 2). Results show that the modified enzymatic extraction method (Method A) is an efficient DNA extraction protocol, while for RNA extraction, the enzymatic method (Method 1) and the Chelex-100 RNA extraction method (Method 2) are equally efficient RNA extraction protocols.
Fulltext MTHFR C677T polymorphism as a risk factor of neural tube defects in Malay: a case control study

Hayati AR, Zainal AI, Tan GC, Ong LC, Khoo TB

Med J Malaysia, 2008 Dec;63(5):379-83.
PMID: 19803295 MyJurnal

Major congenital malformations occur in about 3% of newborn. Several studies have suggested that homozygosity for the C677T methylenetetrahydrofolate reductase (MTHFR) variant is a potential risk factor for neural tube defects (NTDs). It has been hypothesized that the maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme. This association has not been found in some ethnic groups. In this study, we attempted to assess the association between NTDs and MTHFR C677T in Malaysian Malay population. Results show that MTHFR 677TT genotype was absent in both patient and control groups.
Augmentation of angiogenic and endothelial associated gene expression by EDM50 in human chorion-derived stem cells

Manzor NF, Chua KH, Tan GC, Tan AE, Abdul Rahman H

Med J Malaysia, 2008 Jul;63 Suppl A:11-2.
PMID: 19024960

The objective of this study was to investigate the angiogenic potential of human chorion-derived stem cells (CDSC) cultured in medium containing bFGF and VEGF (EDM50). Total RNA was extracted from cells cultured in FD+10% FBS and EDM50. Quantitative RT-PCR was carried out to score the differential mRNA expression of genes involve in angiogenesis and endothelial differentiation. Our finding demonstrated that all angiogenic and endothelial associated genes were expressed higher in EDM50. Expression level of ANG-1, eNOS and VEGFR2 were significantly higher in EDM50 compared to FD+10% FBS. Our results suggested that human CDSC cultured in EDM50 can be used for angiogenesis purpose in regenerative medicine.
Fulltext Small cell variant of anaplastic large cell lymphoma with positive immunoreactivity for CD99

Shiran MS, Tan GC, Sabariah AR, Chye PC, Pathmanathan R

Med J Malaysia, 2008 Jun;63(2):150-1.
PMID: 18942305 MyJurnal

A 13 year old boy presented with a huge mass on his right arm of 6 months duration. Histopathological examination revealed sheets of malignant small round blue cells with immunopositivity for LCA, CD43, CD45Ro, CD30, EMA, ALK-1 and CD99, and negativity for CD20, TdT, myogenin, myoD1, NSE, bcl-6, bcl-2 and CD10. Fluorescent In-Situ Hybridization (FISH) testing excluded the diagnosis of Ewing's sarcoma/PNET. Pathologists need to be aware of the diagnosis of a small cell variant of ALCL, as well as of the fact that CD99 expression commonly occurs in cases of ALK-positive ALCL, in order to distinguish this entity from Ewing's sarcoma/PNET.
The stemness gene expression of cultured human amniotic epithelial cells in serial passages

Simat SF, Chua KH, Abdul Rahman H, Tan AE, Tan GC

Med J Malaysia, 2008 Jul;63 Suppl A:53-4.
PMID: 19024980

The aim of the study is to evaluate the stemness gene expression of cultured human amniotic epithelial cells (HAECs) in serial passages. HAECs obtained from human term placentae were cultured in F12:DMEM(1:1) + 10% FBS +10ng/ml EGF in serial passages (P0, P1, P2 and P4). Quantitative RT-PCR was used to assess the gene expression analysis. The results showed that cultured HAECs expressed and downregulated the stemness genes expression for Oct-4, Sox-2, Nanog3, FGF4, Rex-1, FZD-9, BST-1 ABCG2. However, vimentin and nestin gene expression were upregulated. The results suggested that cultured HAECs may have pluripotent and multipotent properties.
Quantitative RT PCR approach to evaluate the neurogenic and gliagenic gene expression of cultured human amniotic epithelial cells

Tan GC, Simat SF, Abdul Rahman H, Tan AE, Chua KH

Med J Malaysia, 2008 Jul;63 Suppl A:51-2.
PMID: 19024979

The aim of the study is to determine the neuronal and glial gene expression of cultured human amniotic epithelial cells (HAECs) in serial passages. HAECs obtained from human term placentae were cultured in F12:DMEM (1:1) + 10% FBS +10ng/ml EGF in serial passages. Quantitative RT-PCR was used to assess the gene expression analysis. The results showed that the cultured HAECs expressed the neural stem cell genes (Nestin, NSE and Vimentin), mature neuronal genes (TH, MAP-2, beta-III-tubulin and NFM) and glial genes (CNPase, MBP and Olig). These neural stem cell genes increased with serial passages while the genes expression for mature neuronal and glial cells were downregulated. These results suggested that HAECs may promote or involve in neurogenesis and gliagenesis.
Upregulation of SOX-2, FZD9, Nestin, OCT-4 and FGF-4 expression in human chorion derived-stem cells after angiogenic induction

Abdul Rahman H, Manzor NF, Tan GC, Tan AE, Chua KH

Med J Malaysia, 2008 Jul;63 Suppl A:57-8.
PMID: 19024982

Angiogenic induction was made to promote angiogenesis by differentiating stem cells towards endothelial cells. However, the stemness property of induced cells has not been revealed yet. Hence, we aim to evaluate the differential mRNA expression of stemness genes in human chorion-derived stem cells (CDSC) after being cultured in EDM50 comprised bFGF and VEGF. Results indicated that CDSC cultured in EMD50 expressed significantly higher mRNA level of Sox-2, FZD9, BST-1 and Nestin. In addition Oct-4, FGF-4 and ABCG-2 were also upregulated. Our finding suggested that CDSC after angiogenic induction enhanced its stem cell properties. This could be contributed for the mechanism of stem cell therapy in ischemic problem.
Fulltext p63 as a complimentary basal cell specific marker to high molecular weight-cytokeratin in distinguishing prostatic carcinoma from benign prostatic lesions

Shiran MS, Tan GC, Sabariah AR, Rampal L, Phang KS

Med J Malaysia, 2007 Mar;62(1):36-9.
PMID: 17682568 MyJurnal

The diagnosis of prostatic carcinoma (Pca) on routine biopsies may be challenging, and to date the commonly used marker to distinguish prostate carcinoma from benign prostatic lesions has been High Molecular Weight-Cytokeratin (HMW-CK). However, the antigen of HMW-CK is susceptible to the effect of formalin fixation and causes frequent loss or patchy staining in the obviously benign glands. More recently, antibodies to p63 have been reported to be more sensitive than HMW-CK for the detection of prostatic basal cells. p63, a homologue of tumour suppressor gene p53, is essential for prostate development and is selectively expressed in the nuclei of basal cells of normal prostate glands. The objective of this study is to compare the sensitivity and specificity of HMW-CK and p63 in distinguishing prostatic carcinomas from benign prostatic lesions, as well as determining their positive predictive values. Seventy-two cases from HUKM (comprising 29 prostatic carcinomas and 43 benign prostatic hyperplasias) were stained for both HMW-CK and p63. The sensitivity of p63 and HMW-CK in identifying basal cells in benign glands was 88.37% and 90.70% respectively. The specificity of both reagents was 100%, and the positive predictive value for both reagents was also 100%. Thus, p63 is a useful complementary basal cell specific stain to HMW-CK, and would be very helpful to practicing pathologists in dealing with difficult cases.
Fulltext NK/T cell lymphoma associated with peripheral eosinophilia

Yap E, Wan Jamaluddin WF, Tumian NR, Mashuri F, Mohammed F, Tan GC, et al.

Malays J Pathol, 2014 Dec;36(3):201-5.
PMID: 25500520 MyJurnal

NK/T cell lymphoma, nasal type is an aggressive and uncommon malignancy. Disease that occurs outside of the aerodigestive tract exhibits an even more aggressive clinical behaviour and does not respond as well to conventional therapy compared to its nasal counterpart. We report such a case of NK/T cell lymphoma, nasal type, that presented as an anterior chest wall mass, arising from the left pectoralis muscle. An interesting feature we wish to highlight is the associated eosinophilia that corresponded to disease activity, exhibiting fluctuations with surgical resection and chemotherapy. To the best of our knowledge this is the third reported case of NK/T cell lymphoma that is associated with peripheral eosinophilia. Our case highlights the role of certain NK cell subsets that play a major role in eosinophilic activation in NK/T lymphomas and calls for more research into further classification of this disease by virtue of its NK cell subsets.
Fulltext An immunohistochemical study of Toll-like receptors 2 and 4 in placenta with and without infection

Hayati AR, Mohamed AE, Tan GC

Malays J Pathol, 2010 Jun;32(1):13-9.
PMID: 20614721 MyJurnal

The placenta constitutes a physical and immunological barrier against infectious agents. Toll-like receptors (TLRs) are essential components for the induction of innate immunity responses in different human tissues including the placenta. We investigated the expressions of TLR2 and TLR4 in the decidua and amniotic cells in non-inflamed placenta and placenta with infection.
Fulltext Multifocal nodal and extranodal Rosai-Dorfman disease initially diagnosed as histiocytic lymphoma

Shiran MS, Tan GC, Kenali MS, Sabariah AR, Pathmanathan R

Malays J Pathol, 2008 Jun;30(1):63-5.
PMID: 19108414 MyJurnal

Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy (SHML), is a systemic disease involving nodal and extranodal tissues. We report a 48-year-old female with recurrent nasal obstruction due to polypoidal masses involving the nasal sinuses, turbinates and septum bilaterally, and lumps in the right infra-orbital region and region of the right lacrimal sac. A 4 cm right upper neck mass was also noted, which was initially diagnosed as histiocytic lymphoma. Histopathology of the nasal and infraorbital lesions revealed fibro-inflammatory masses containing histiocytic cells with large vesicular nuclei and abundant foamy cytoplasm exhibiting emperipolesis and lymphophagocytosis, admixed with scattered plasma cells and lymphocytes. These histiocytes revealed immunohistochemical positivity for S-100 protein and CD68, but were negative for CDla. The findings supported a diagnosis of RDD. This report serves to remind pathologists and clinicians of the extranodal manifestations of RDD and its potential confusion with lymphomas.
Clear cell "sugar" tumour of the lung: a case report

Shiran MS, Tan GC, Arunachalam N, Sabariah AR, Pathmanathan R

Malays J Pathol, 2006 Dec;28(2):113-6.
PMID: 18376801

We report a case of clear cell "sugar" tumour of the lung (CCTL) occurring in a 26-year-old lady. The patient was asymptomatic and the lesion was picked up in the course of a pre-employment medical examination. A well-defined 5 cm nodule in the right lower lobe was detected on routine chest X-Ray. Microscopical examination of the coin lesion showed clear cells containing abundant diastase-sensitive intracytoplasmic glycogen, as demohstrated with periodic acid-Schiff stains. Tumour immunoreactivity for HMB-45 and non-reactivity for cytokeratin support the histological diagnosis. To our knowledge, this is the first reported case of CCTL in Malaysia.
Fulltext IsomiRs have functional importance

Tan GC, Dibb N

Malays J Pathol, 2015 Aug;37(2):73-81.
PMID: 26277662 MyJurnal

Since the inception of deep sequencing, isomiRs are consistently observed to be produced by most miRNA genes in a variety of cell types. IsomiRs appear as a variation in length from the canonical sequence annotated in miRBase, due to an addition or deletion of one or more nucleotides at the 5(') or 3(') ends or both. As the seed sequence is located at the 5(') end of the microRNA, the target mRNA will be theoretically different. Therefore, 5(')isomiRs might potentially target a new set mRNA compared to their canonical counterpart. This article gives an overview of investigations that explored the functional potential of isomiRs such as their ability to incorporate into Argonaute protein, the differential expression of isomiRs in various tissue types and cell lines, and the differences of mRNA targets between isomiR and its canonical microRNA. In addition, this article provides a brief introduction of RNA sponges as a potential way to inhibit isomiRs.
Gardnerella vaginalis in perinatology: An overview of the clinicopathological correlation

Wong YP, Tan GC, Wong KK, Anushia S, Cheah FC

Malays J Pathol, 2018 Dec;40(3):267-286.
PMID: 30580358

Gardnerella vaginalis (GV) is a facultatively anaerobic gram-variable bacillus and is the major organism involved in bacterial vaginosis. GV-associated bacterial vaginosis has been associated with adverse pregnancy outcomes include preterm parturition and subclinical chorioamnionitis. Inflammatory response induced by GV presents paediatric problems as well. Studies had shown that increased levels of proinflammatory cytokines include TNF-α, IL-1β and IL-6 following fetal inflammatory response syndrome secondary to GV-induced intrauterine infection may result in the development of periventricular leukomalacia and bronchopulmonary dysplasia in the infected fetus. There is increasing evidence that GV-associated BV infection serves as a risk factor for long-term neurological complications, such as cerebral palsy and learning disability. GV is fastidious and could elude conventional detection methods such as bacterial cultures. With current more sophisticated molecular biology detection methods, its role and pathogenic effects have been shown to have a greater impact on intrauterine inflammation and fetal/neonatal infection. This review gives an overview on the characteristics of GV and its virulence properties. Its detrimental role in causing unfavourable GV-related perinatal outcomes, with emphasis on the possible mechanistic pathways is discussed. The discovery of disease mechanisms allows the building of a strong platform where further research on innovative therapies can be based on, for instance, an anti-TLR monoclonal antibody as therapeutic agent to halt inflammation-precipitate adverse perinatal outcomes.
Androgen receptor expression in triple negative breast carcinoma and its association with the clinicopathological parameters

Teoh PY, Tan GC, Mahsin H, Wong YP

Malays J Pathol, 2019 Aug;41(2):125-132.
PMID: 31427547

INTRODUCTION: Androgen receptor (AR) is the most frequently expressed biomarker in all subtypes of breast carcinoma. Triple negative breast carcinoma (TNBC) is breast carcinoma that lacks oestrogen and progesterone receptors immunoexpression as well as absence of HER2/neu gene amplification. This makes targeted therapy not feasible in this cancer and hence has poorer prognosis. Detecting AR expression could be another milestone in the management of TNBC, as AR is a prognostic, predictive marker and potential index for targeted treatment. This study aimed to assess expression of AR in TNBC by immunohistochemistry and its association with clinicopathological parameters.
METHODS: We analysed the expression of AR in 97 TNBC cases from Penang General Hospital for a period of 3 years (2014 to 2017). Androgen receptor immunoreactivity was considered positive if ≥ 1% of tumour cells nuclei were stained irrespective of staining intensity.
RESULTS: The prevalence of AR expression in TNBC was 31% (30/97), with the proportion of AR-positive tumour cells ranged from 1% to 90%. These include 23 invasive carcinomas, no special type (NST) and 7 other invasive carcinoma subtypes (papillary, lobular, clear cell and medullary carcinomas). Sixty-seven cases (69%) that showed AR immunonegativity were invasive carcinomas, NST (n=60), clear cell carcinoma (n=1) and metaplastic carcinoma (n=6). Androgen receptor immunoexpression was inversely correlated with tumour grade (p=0.016), but not the tumour stage, tumour size and nodal status.
CONCLUSION: AR is expressed in about one-third of TNBC and loss of AR immunoexpression does not predict adverse clinical outcomes. Larger cohorts for better characterisation of the role of AR immunoexpression in TNBC are warranted.

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