Displaying publications 21 - 40 of 43 in total

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  1. Human cytokeratin 1 plays a role in the interaction of Pteropine orthoreovirus with Hek293 cells but not HeLa cells
    Siew ZY, Tan YF, Iswara RP, Wong SF, Wong ST, Tan BK, et al.
    Microbes Infect, 2024;26(1-2):105243.
    PMID: 38380604 DOI: 10.1016/j.micinf.2023.105243
    Pteropine orthoreovirus (PRV) causes respiratory tract infections in humans. Despite its emergence as a zoonotic and respiratory virus, little is known about its cell tropism, which hampers progress in fully understanding its pathogenesis in humans. Hek293 cells are most susceptible to PRV infection, while HeLa cells are the least. Human cytokeratin 1 (CK1) was identified as the protein that interacts with PRV. The immunofluorescence assay and qPCR results revealed prior treatment with anti-CK1 may provide Hek293 cells protection against PRV. The KRT1-knockout Hek293 cells were less susceptible to PRV infection. Further study into the pathogenesis of PRV in humans is needed.
    Matched MeSH terms: Keratins
  2. Odontogenic keratocyst: a clinical experience in Singapore
    Chow HT
    Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1998 Nov;86(5):573-7.
    PMID: 9830650
    The odontogenic keratocyst has been well documented and extensively studied. It is of particular interest because of its high recurrence rate and aggressive nature. The material for this study consisted of 70 cases of odontogenic keratocysts in predominantly ethnic Chinese patients who were treated from 1981 to 1996. The cases were retrospectively studied to compare characteristics of the lesion in this population with those in previous reports. Most of the patients in this series were 21 to 30 years of age. Association with an impacted mandibular third molar was found in more than 50% of the cases. The recurrence rate was 20% for 35 patients with a follow-up period of at least 5 years. The follow-up period for the whole series ranged from 1 to 16 years. Treatment was surgical enucleation with peripheral ostectomy. There were no significant differences in characteristics with respect to presentation and prognosis between this series and those described in previous publications.
    Matched MeSH terms: Keratins/analysis
  3. Clear cell sarcoma of kidney: report of the first Malaysian case
    Looi LM, Cheah PL, Lin HP
    Pathology, 1992 Jan;24(1):34-6.
    PMID: 1374551
    Clear cell sarcoma of kidney (CCSK) is a rare but distinct tumor of childhood frequently confused with Wilms' tumor (nephroblastoma). It has a characteristic histology, a marked predilection for metastasis to bone, and an aggressive clinical course with a high relapse rate in spite of surgical excision, chemotherapy and radiotherapy. We report the first histologically proven CCSK in a Malaysian patient. This was an 8-mth-old Malay boy who was clinically diagnosed to have stage I Wilms' tumor. Despite treatment, he developed multiple metastases 10 mths after initial presentation and died soon after. Emphasis is placed on recognizing this entity in view of (1) its naturally aggressive behaviour and (2) the prospect of improving prognosis with currently recommended intensified chemotherapeutic regimes. Its immunohistochemical profile of vimentin-positivity and negativity for epithelial membrane antigen, cytokeratin and Factor-8 related antigen is more in favour of a mesenchymal or glomerular origin than a tubular or vascular origin.
    Matched MeSH terms: Keratins/analysis
  4. Fulltext Potential use of human hair shaft keratin peptide signatures to distinguish gender and ethnicity
    Mohamed Nasir N, Hiji J, Jayapalan JJ, Hashim OH
    PeerJ, 2020;8:e8248.
    PMID: 32030317 DOI: 10.7717/peerj.8248
    Background: Most human hairs collected at old crime scenes do not contain nuclear DNA and are therefore of less value for forensic investigations. In the present study, hair shaft proteins were extracted from 40 healthy subjects between the ages of 21 to 40 years and profiled using gel electrophoresis-based proteomics to determine if they can be used to distinguish gender and ethnicity.

    Methods: Extraction of the human hair shaft proteins was performed using a newly developed alkaline solubilisation method. The extracts were profiled by 2-dimensional electrophoresis and resolved protein spots were identified by mass spectrometry and queried against the human hair database. The study was then followed-up by immunoblotting of the identified hair shaft keratin of interest using commercially available antibodies.

    Results: Separation of the human hair shaft proteins by 2-dimensional electrophoresis generated improved and highly resolved profiles. Comparing the hair shaft protein profiles of 10 female with 10 male subjects and their identification by mass spectrometry and query of the human hair database showed significant altered abundance of truncated/processed type-II keratin peptides K81 (two spots), K83 (one spot) and K86 (three spots). The 2-dimensional electrophoresis profiling of 30 hair shaft samples taken from women of similar age range but from three distinctive ethnic subpopulations in Malaysia further showed significant altered abundance of one type-I and four type-II truncated/processed keratin peptides including K33b, K81, K83 and K86 (2 spots) between at least two of the ethnic groups. When a followed-up immunoblotting experiment was performed to detect the relative expression of the K86 peptides using commercialised antibodies, similar trends of expression were obtained. The present data, when taken together, demonstrated the potential use of keratin peptide signatures of the human hair shaft to distinguish gender and ethnicity although this needs to be further substantiated in a larger scale study.

    Matched MeSH terms: Keratins; Keratins, Type II
  5. Fulltext A High-Yield Two-Hour Protocol for Extraction of Human Hair Shaft Proteins
    Wong SY, Lee CC, Ashrafzadeh A, Junit SM, Abrahim N, Hashim OH
    PLoS One, 2016;11(10):e0164993.
    PMID: 27741315 DOI: 10.1371/journal.pone.0164993
    Proteome analysis of the human hair remains challenging due to the poor solubility of hair proteins and the difficulty in their extraction. In the present study, we have developed a rapid extraction protocol for hair shaft protein using alkaline-based buffer. The new protocol accelerated the procedure by reducing the extraction time from at least a day to less than two hours and showed a protein recovery of 47.3 ± 3.72%. Further analyses of the extracted protein sample through sodium dodecyl sulfate polyacrylamide gel electrophoresis and Quadrupole-time-of-flight mass spectrometry analysis unveiled a total of 60 proteins, including 25 that were not previously reported. Identification of these proteins is anticipated to be crucial in helping to understand the molecular basis of hair for potential applications in the future.
    Matched MeSH terms: Keratins/analysis; Keratins/isolation & purification; Keratins/metabolism
  6. Fulltext Development of high-performance two-dimensional gel electrophoresis for human hair shaft proteome
    Wong SY, Hashim OH, Hayashi N
    PLoS One, 2019;14(3):e0213947.
    PMID: 30889197 DOI: 10.1371/journal.pone.0213947
    The primary components of human hair shaft-keratin and keratin-associated proteins (KAPs), together with their cross-linked networks-are the underlying reason for its rigid structure. It is therefore requisite to overcome the obstacle of hair insolubility and establish a reliable protocol for the proteome analysis of this accessible specimen. The present study employed an alkaline-based method for the efficient isolation of hair proteins and subsequently examined them using gel-based proteomics. The introduction of two proteomic protocols, namely the conventional and modified protocol, have resulted in the detection of more than 400 protein spots on the two-dimensional gel electrophoresis (2DE). When compared, the modified protocol is deemed to improve overall reproducibility, whilst offering a quick overview of the total protein distribution of hair. The development of this high-performance protocol is hoped to provide a new approach for hair analysis, which could possibly lead to the discovery of biomarkers for hair in health and diseases in the future.
    Matched MeSH terms: Keratins/analysis; Keratins/isolation & purification
  7. Fulltext NTCU induced pre-malignant and malignant stages of lung squamous cell carcinoma in mice model
    Zakaria MA, Rajab NF, Chua EW, Selvarajah GT, Masre SF
    Sci Rep, 2021 Nov 18;11(1):22500.
    PMID: 34795360 DOI: 10.1038/s41598-021-01988-8
    Mice have served as an excellent model to understand the etiology of lung cancer for years. However, data regarding dual-stage carcinogenesis of lung squamous cell carcinoma (SCC) remain elusive. Therefore, we aim to develop pre-malignant (PM) and malignant (M) lung SCC in vivo using N-nitroso-tris-chloroethylurea (NTCU). BALB/C mice were allotted into two main groups; PM and M groups which received treatment for 15 and 30 weeks, respectively. Then, the mice in each main group were allotted into three groups; control, vehicle, and cancer (n = 6), which received normal saline, 70% acetone, and 0.04 M NTCU by skin painting, respectively. Histopathologically, we discovered a mix of hyperplasia, metaplasia, and dysplasia lesions in the PM group and intracellular bridge; an SCC feature in the M group. The M group was positive for cytokeratin 5/6 protein which confirmed the lung SCC subtype. We also found significantly higher (P 
    Matched MeSH terms: Keratins/metabolism
  8. 'Combined ameloblastoma and odontogenic keratocyst' or 'keratinising ameloblastoma'
    Siar CH, Ng KH
    Br J Oral Maxillofac Surg, 1993 Jun;31(3):183-6.
    PMID: 7685634
    Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.
    Matched MeSH terms: Keratins/analysis
  9. Orthokeratinised odontogenic keratocysts in Malaysians
    Siar CH, Ng KH
    Br J Oral Maxillofac Surg, 1988 Jun;26(3):215-20.
    PMID: 2456095
    The records of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, Malaysia, were reviewed for the incidence of odontogenic keratocysts of the orthokeratinised variety, during the 20-year-period, 1967 to 1986. Nine cases were found. The clinical, histological and radiological features of these cases are reported. Many features were similar to previous reports of this entity but a peak incidence in the second decade of life, an almost even distribution in the maxilla and mandible, and a distinct predilection for the Chinese were observed. It is suggested that these features may be peculiar to Malaysians.
    Matched MeSH terms: Keratins
  10. An immunohistochemical study of the lining epithelium of odontogenic keratocyst
    Siar CH, Ng KH
    J Nihon Univ Sch Dent, 1995 Sep;37(3):163-9.
    PMID: 7490610
    The lining epithelium of 15 cases of odontogenic keratocyst (OKC) was evaluated immunohistochemically. The peroxidase-antiperoxidase technique was applied to study the distribution of polyclonal keratin and S-100 protein while the indirect method was used to examine monoclonal vimentin and desmin reactivity. Consistent positive keratin staining was revealed in the lining epithelium of all 15 OKCs with additional intense staining in the stratum corneum. None of the cases showed vimentin or desmin reactivity within the lining epithelium elements. One of the 15 cysts studied showed positive S-100 protein staining in the nuclei of the lining epithelial cells. The pertinent literature on the immunophenotyping of the lining epithelium of OKC is reviewed.
    Matched MeSH terms: Keratins/analysis
  11. An immunohistochemical study of two cases of either peripheral odontogenic fibroma (WHO type) or peripheral ameloblastoma
    Chong Huat Siar, Kok Han Ng
    J Nihon Univ Sch Dent, 1996 Mar;38(1):52-6.
    PMID: 8648412
    Two cases of either peripheral odontogenic fibroma (POF) (WHO type) or peripheral ameloblastoma are reported. Their immunohistochemical characteristics were investigated in an attempt to clarify their histogenesis. The results showed that the epithelial component of this neoplasm tended to retain its distinct odontogenic character and expressed a keratin profile different from that of the overlying oral epithelium from which both cases most probably originated. The connective tissue element of these tumors was vimentin-positive and S-100 protein negative, confirming their mesodermal nature but precluding the possibility of ectomesenchymal derivation. No reactivity for desmin was noted.
    Matched MeSH terms: Keratins/analysis
  12. Unusual granular cell odontogenic tumor. Report of two undescribed cases with features of granular cell ameloblastoma and plexiform granular cell odontogenic tumor
    Siar CH, Ng KH
    J Nihon Univ Sch Dent, 1993 Jun;35(2):134-8.
    PMID: 7692017
    Granular cell ameloblastoma (GCA) is a well recognized variant of follicular ameloblastoma with extensive granular cell change. In contrast, plexiform granular cell odontogenic tumor (PGCOT) is a rare and recently described lesion characterized histologically by a monophasic plexiform pattern of granular cells. In this paper, two cases of an unusual granular cell odontogenic tumor exhibiting combined features of these two entities are described along with their immunohistochemical characteristics. The granular cells of both the GCA and PGCOT areas showed similar patterns of expression for keratin and S-100, which differed from those of typical ameloblastoma. No reactivity for desmin or vimentin was noted. The histomorphologic and immunohistochemical features of these hybrid tumors suggest that the granular cells present have a common origin, most probably the odontogenic epithelium.
    Matched MeSH terms: Keratins/analysis
  13. Patterns of expression of intermediate filaments and S-100 protein in desmoplastic ameloblastoma
    Siar CH, Ng KH
    J Nihon Univ Sch Dent, 1993 Jun;35(2):104-8.
    PMID: 7692015
    Seventeen cases of desmoplastic ameloblastoma were examined immunohistochemically. Immunoperoxidase techniques were applied for detection of keratin, desmin, vimentin and S-100 protein expression in these tumors. The tumor epithelium of desmoplastic ameloblastoma exhibited weak, focal, inconstant keratin staining, weak, variable expression of S-100 protein, desmin immunoreactivity of mild to moderate intensity and vimentin non-reactivity. The pertinent literature on the immunohistochemistry of ameloblastomas is briefly reviewed.
    Matched MeSH terms: Keratins/analysis
  14. A clinicopathological and immunohistochemical study of the calcifying epithelial odontogenic tumour (Pindborg tumour) in Malaysians
    Ng KH, Siar CH
    J Laryngol Otol, 1996 Aug;110(8):757-62.
    PMID: 8869610
    We reviewed the clinicopathological characteristics of 13 cases of calcifying epithelial odontogenic tumour (CEOT) (Pindborg tumour) diagnosed in the Division on Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period. There were eight female and five male patients. These consisted of eight (61.5 per cent) Malays, three (23.1 per cent) Chinese, one (7.7 per cent) Indian and one (7.7 per cent) Melanau. Their ages at presentation ranged from 19-61 years (mean age, 31.8 years). There were 12 central and one peripheral CEOT. Of these, 76.9 per cent of cases were located in the maxilla, the remaining in the mandible. The commonest clinical diagnosis was a dentigerous cyst (66.7 per cent). Enucleation was the main mode of treatment. Histologically, sheets and strands of polyhedral epithelial cells containing eosinophilic, homogeneous globules with Liesegang rings were observed. One case also showed extensive calcification and clear cell differentiation. Immunohistochemistry revealed a variable keratin staining of the CEOT epithelium, confirming its heterogeneity.
    Matched MeSH terms: Keratins/analysis
  15. Calcifying and keratinizing ameloblastoma of the maxilla
    Siar CH, Ng KH
    J Laryngol Otol, 1991 Nov;105(11):971-2.
    PMID: 1722237
    A case is described of ameloblastoma of maxilla presenting with numerous calcified keratin pearls. The significance of cellular variation in relation to the behavioural potential of the ameloblastoma in general is briefly discussed.
    Matched MeSH terms: Keratins
  16. Phenotypic and molecular dissection of metaplastic breast cancer and the prognostic implications
    McCart Reed AE, Kalaw E, Nones K, Bettington M, Lim M, Bennett J, et al.
    J Pathol, 2019 02;247(2):214-227.
    PMID: 30350370 DOI: 10.1002/path.5184
    Metaplastic breast carcinoma (MBC) is relatively rare but accounts for a significant proportion of global breast cancer mortality. This group is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including spindle, squamous, chondroid, osseous, and rhabdomyoid features. Clinically, patients are more likely to present with large primary tumours (higher stage), distant metastases, and overall, have shorter 5-year survival compared to invasive carcinomas of no special type. The current World Health Organisation (WHO) diagnostic classification for this cancer type is based purely on morphology - the biological basis and clinical relevance of its seven sub-categories are currently unclear. By establishing the Asia-Pacific MBC (AP-MBC) Consortium, we amassed a large series of MBCs (n = 347) and analysed the mutation profile of a subset, expression of 14 breast cancer biomarkers, and clinicopathological correlates, contextualising our findings within the WHO guidelines. The most significant indicators of poor prognosis were large tumour size (T3; p = 0.004), loss of cytokeratin expression (lack of staining with pan-cytokeratin AE1/3 antibody; p = 0.007), EGFR overexpression (p = 0.01), and for 'mixed' MBC, the presence of more than three distinct morphological entities (p = 0.007). Conversely, fewer morphological components and EGFR negativity were favourable indicators. Exome sequencing of 30 cases confirmed enrichment of TP53 and PTEN mutations, and intriguingly, concurrent mutations of TP53, PTEN, and PIK3CA. Mutations in neurofibromatosis-1 (NF1) were also overrepresented [16.7% MBCs compared to ∼5% of breast cancers overall; enrichment p = 0.028; mutation significance p = 0.006 (OncodriveFM)], consistent with published case reports implicating germline NF1 mutations in MBC risk. Taken together, we propose a practically minor but clinically significant modification to the guidelines: all WHO_1 mixed-type tumours should have the number of morphologies present recorded, as a mechanism for refining prognosis, and that EGFR and pan-cytokeratin expression are important prognostic markers. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
    Matched MeSH terms: Keratins/analysis
  17. Cytokeratin immunoreactivity in Ewing sarcoma/ primitive neuroectodermal tumour
    Elbashier SH, Nazarina AR, Looi LM
    Malays J Pathol, 2013 Dec;35(2):139-45.
    PMID: 24362477
    Ewing sarcoma (ES)/ primitive neuroectodermal tumour (PNET) is an aggressive malignant neoplasm affecting mainly children and young adults. The tumour is included with other primitive neoplasms under the category of small round cell tumour. Cytokeratin expression in ES/PNET has been described in sporadic case reports as well as a few systemic series. We studied this feature in Malaysian patients diagnosed in University Malaya Medical Centre on the basis of typical morphology and immunohistochemical assays. Immunohistochemical staining for AE1/AE3 and MNF116 were performed in 43 cases. Cytokeratin was expressed in 17 cases (39.5%) in focal, intermediate or diffuse patterns. There was no significant association between cytokeratin immunoreactivity and the following parameters: patient age, sex, skeletal and extraskeletal primary location as well as primary, metastastic or recurrent tumours or chemotherapy treatment. A significant association between cytokeratin and neuron specific enolase (NSE) expression was demonstrated. Our study supports evidence of epithelial differentiation in ES/PNET and emphasizes that the expression of cytokeratin does not exclude ES/PNET in the differential diagnosis of small round cell tumours.
    Matched MeSH terms: Keratins/analysis; Keratins/biosynthesis*
  18. Fine needle aspiration cytology of undifferentiated embryonal sarcoma of the liver: a case report
    Sharifah NA, Muhaizan WM, Rahman J, Zulfikar A, Zahari Z
    Malays J Pathol, 1999 Dec;21(2):105-9.
    PMID: 11068415
    The cytological features of a rare case of undifferentiated (embryonal) sarcoma of the liver are presented. The cytology smears showed singly dispersed polygonal and spindle cells as well as loose clusters of cells held together in myxoid material. Neoplastic cells were generally large with round, oval or lobulated nuclei. The cytoplasm was variable in amount with ill-defined borders. Occasional multinucleated cells were also present. Hyaline globules were present on sections of the cell block. Immunohistochemical studies performed showed positivity for vimentin, cytokeratin and alpha-1-antitrypsin (AAT) in the tumour cells.
    Matched MeSH terms: Keratins/analysis
  19. Malignant rhabdoid tumour of the kidney: report of a case showing focal glomeruloid differentiation
    Jayaram G, Looi LM
    Malays J Pathol, 1994 Jun;16(1):83-7.
    PMID: 16329582
    A five-month-old male baby presented with an abdominal mass which was found on computerised tomography (CT) to be involving the left kidney. Nephrectomy and histopathological study showed morphological featues of a malignant rhabdoid tumour. The tumour cells stained strongly for cytokeratin and epithelial membrane antigen and less intensely for vimentin. Electron microscopy revealed concentric whorled arrays of intermediate filaments within the tumour cell cytoplasm. The child was put on post-operative chemotherapy and radiotherapy but developed bilateral lung metastases and died three months after surgery.
    Matched MeSH terms: Keratins/analysis
  20. Nasopharyngeal undifferentiated carcinoma with sarcomatoid features: Pitfalls in the immunohistochemistry
    Lee M, Son HJ, Kim NY, Kim SJ, Yu IK
    Malays J Pathol, 2019 Aug;41(2):201-206.
    PMID: 31427557
    We present a case of an undifferentiated subtype of non-keratinizing squamous cell carcinoma (NK-SCC) with sarcomatoid features in the nasopharynx in a 69-year-old man who was difficult to diagnose due to spindle-shaped malignant cells. He was admitted because of a right nasal obstruction and right headache, and imaging revealed a heterogeneously enhanced irregularly shaped mass at the nasopharynx. Histopathologically, the tumour was partially organised, and the tumour cells were epithelioid or spindle-shaped. Initially, we erroneously diagnosed the tumour as an angiosarcoma owing to its false-negative immunoreaction for cytokeratins and a mistaken interpretation for CD31. After in situ hybridization for Epstein-Barr virus was positive, a consultation and additional immunostaining (including re-staining for cytokeratin with varying dilutions) were performed, and the diagnosis was revised to NK-SCC with sarcomatoid features. We believe that sarcomatoid features may be observed in nasopharyngeal carcinoma and in this case, immunostaining using various epithelial markers is necessary and careful attention should be paid to the interpretation of immunostaining.
    Matched MeSH terms: Keratins
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