Displaying publications 1 - 20 of 26 in total

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  1. Prasad U, Rajamani R
    Singapore Med J, 1972 Oct;13(5):239-44.
    PMID: 4651729
    Papillomas of nose and paranasal sinuses are uncommon tumours. Based on the detailed clinical and
    histopathological examination of seven cases of papillomas, the authors would accept and recommend
    t~e. su~ested unifying name of transitional cell papilloma for these lesions which may further be sub·
    dIvIded onto Type I and Type II. The rationale behind this classification is discussed at length. There is
    a greater tendency for Type II papillomas to recur and undergo malignant change. It is suggested that
    Type I papillomas be managed by relatively simple surgical procedures whereas Type II cases be dealt with more radically.
  2. Simons MJ, Chan SH, Wee GB, Shanmugaratnam K, Goh EH, Ho JH, et al.
    PMID: 730194
    New data are presented concerning the relationship between NPC and HLA antigens among Chinese. When attention is confined to newly diagnosed cases, it can be shown that, apart from the increased risk associated with the joint occurrence of A2 and B-Sin 2, there is also an increased risk associated with BW17 and a decrease in risk associated with A11. Among long-term survivors, however, BW17 is appreciably decreased, whereas A2 in the absence of B-Sin 2 or BW17 is increased. Among Malays, a non-Chinese group, there is an excess among NPC patients of a locus A blank, a blank which is probably associated with the AW19 complex.
  3. Singh AP, Prasad U
    Med J Malaysia, 1982 Sep;37(3):223-6.
    PMID: 7177003
    This paper describes eight cases of successfully treated laryngeal cysts in different age groups with varying presentation problems.
  4. Singh AP, Prasad U, Kumar N
    Singapore Med J, 1983 Dec;24(6):367-73.
    PMID: 6681493
    Clinical synopsis and investigations on fourteen patients with blast injuries of the ear successfully treated at the ENT Unit of the University Hospital, Kuala Lumpur, revealed few interesting observations in addition to usual findings. The most outstanding one was the absence of sensorineural deafness, although it has been claimed as one of the most constant features. Conservative management alone was found to be of significant value.
  5. Yadav M, Prasad U
    PMID: 6095462
    The antibody titres to P. falciparum and Epstein-Barr Virus-associated antigens were assayed in 22 patients with NPC and 43 controls. All, but one patient had antimalarial titres; 14 had titres greater than 80 and 4 patients greater than 640. Compared to controls the mean anti-malarial titre for most age groups were higher in the patients. Those patients with high anti-malarial titres also had high IgA anti-VCA titre, an antibody which has been demonstrated to be diagnostic for NPC. The peak anti-VCA (IgG) and anti-EA (IgG) antibody titres were associated with anti-falciparum titres of 320-640 and 80-160, respectively. The results are discussed in relation to the possible association between malarial infection and etiology of NPC.
  6. Chan SH, Chew CT, Prasad U, Wee GB, Srinivasan N, Kunaratnam N
    Br. J. Cancer, 1985 Mar;51(3):389-92.
    PMID: 3855643
    HLA associations were observed in unrelated Malay patients with nasopharyngeal carcinoma (NPC). HLA-B18 was observed in 18/45 (40%) Malay NPC patients compared to 22/167 (13%) Malay normals (P = 0.0001; Pc = 0.0027, RR = 4.4). The frequency of HLA-B17, one of the antigens associated with Chinese NPC, was also increased among Malay NPC (13/45 29%) compared to controls (18/167 11%; P = 0.003, Pc = 0.07 RR = 3.4). Similar to the findings among Chinese NPC, the frequency of B17 was higher in early onset (less than or equal to 30 years) Malay NPC resulting in a higher relative risk (RR = 5.0).
  7. Jayalakshmi P, Pathmanathan R, Raman R, Prasad U
    Med J Malaysia, 1989 Mar;44(1):58-63.
    PMID: 2626114
    A retrospective study of 1000 cases of microscopically diagnosed head and neck cancers in the University Hospital, Kuala Lumpur was done. Head and neck neoplasms comprise 7.1% of all tumours diagnosed in this Hospital and the commonest sites of involvement are the nasopharynx (29.1%), cervical lymph nodes (22.6%), oral cavity (10.2%), thyroid (8.2%) and skin (6.5%). Histologically, 87% of tumours are epithelial in nature. The results of this study show that nasopharyngeal carcinoma is commonest in Chinese males, while oral and laryngeal malignancies occur more frequently in Indians.
  8. Sam CK, Prasad U, Pathmanathan R
    Eur J Surg Oncol, 1989 Aug;15(4):357-60.
    PMID: 2547665
    The titres of IgA against Epstein-Barr virus, viral capsid antigens and the titres of IgG against early antigen were found to be useful markers for the diagnosis of different histopathological types of nasopharyngeal carcinoma.
  9. Thoe SY, Sam CK, Cheng HM, Prasad U
    J Med Virol, 1989 Dec;29(4):311-4.
    PMID: 2559955
    Serum antibodies against Epstein-Barr virus (EBV)-determined antigens have traditionally been titrated by the indirect immunofluorescence (IIF) technique. The avidin-biotin complex (ABC) immunocytochemical technique was used to determine the serum levels of IgA against EBV viral capsid antigen (IgA/VCA) and IgA against EBV early antigen (IgA/EA) in sera of 106 nasopharyngeal carcinoma (NPC) patients prior to treatment and 100 normal individuals. The sensitivity of the ABC technique is enhanced by an amplification of the antigen-antibody reaction, which involves the binding of the enzyme-linked ABC to the second biotinylated antibody. There was a good correlation (r = 0.9988) between ABC and IIF-determined IgA/VCA-positive titres, with the ABC technique being more sensitive than IIF in the detection of IgA/VCA in NPC sera: 94% (99/106) and 76% (80/106), respectively. The frequency of IgA/EA reactivity in NPC sera was also markedly increased by immunodetection with the ABC technique as compared with IIF technique: 63% (69/106) and 28% (30/106) respectively. Both the immunocytochemical techniques were equally specific in discriminating between elevated serum titres of IgA/VCA and IgA/EA in NPC sera from normal human sera.
  10. Khanijow VK, Prasad U, Chang CM
    Med J Malaysia, 1989 Dec;44(4):329-33.
    PMID: 2520043
    Nasopharyngeal carcinoma (NPC) is one of the commonest presentation of head and neck cancers in Malaysia, especially in the Chinese. The standard treatment is radical radiotherapy to the post-nasal space and the neck. Chemotherapy is given to patients with primary advanced disease and to patients with recurrence. The study reviews results of chemotherapy given to 33 patients at the University Hospital, Kuala Lumpur, over the last four years.
  11. Permeen AM, Sam CK, Pathmanathan R, Prasad U, Wolf H
    J Virol Methods, 1990 Mar;27(3):261-7.
    PMID: 2157729
    The presence of Epstein Barr virus (EBV) DNA in biopsies from the post-nasal space (PNS) of patients suspected of nasopharyngeal carcinoma (NPC) was detected by in situ cytohybridization with an EBV DNA probe labelled with the novel labelling compound digoxigenin. The digoxigenin probe was hybridised to cryostat sections of NPC biopsies and subsequently detected by an enzyme immunoassay procedure. It was found that in situ cytohybridization using the digoxigenin probe was much more rapid and sensitive (96 h compared to five weeks) than the current method of using 3H-labelled probe. Using the digoxigenin EBV probe, it was found that in all the eighteen NPC biopsies tested, EBV DNA was detected in malignant epithelial cells and infiltrating lymphocytes. EBV DNA was also detected in some normal epithelial cells in these NPC biopsies. EBV DNA was not detected in epithelial cells of non-malignant biopsies.
  12. Foong YT, Cheng HM, Sam CK, Dillner J, Hinderer W, Prasad U
    Int J Cancer, 1990 Jun 15;45(6):1061-4.
    PMID: 1693600
    The Epstein-Barr virus nuclear antigen I (EBNA I) is the only latent EBV antigen consistently expressed in malignant tissues of the nasopharynx. A 20-amino-acid synthetic peptide, p107 contains a major epitope of EBNA I. We tested sera from 210 patients with nasopharyngeal carcinoma (NPC) and from 128 normal individuals (NHS) for IgA antibodies to p107 using an enzyme-linked immunosorbent assay (ELISA). Whereas 191/210 (91%) of NPC patients had IgA antibodies to p107, only 17/128 (13.3%) of NHS had such antibodies and only 6/57 (10.5%) of sera from patients with malignancies other than NPC had IgA-p107 reactivity. Thirty-nine salivary samples from 46 NPC patients (84.8%) also contained IgA-p107 antibodies whereas only 3/42 (7.1%) of normal saliva samples were IgA-p107 positive. The results suggest that IgA antibodies to EBNA I may become a useful, easily measurable, marker for NPC.
  13. Prasad U, Doraisamy S
    Eur J Surg Oncol, 1991 Oct;17(5):536-40.
    PMID: 1936303
    Five rare cases of nasopharyngeal carcinoma with optic nerve involvement are reported. Computerised Tomographic Scan (CT Scan) studies were performed in four of them. Evidence of intracranial spread of the tumour, from the roof of the fossa of Rosenmuller to the apex of the orbit through the cavernous sinus, was noted in three patients. In one of them there was extracranial extension of the tumour, to the orbit through the posterior ethmoid.
  14. Prasad U, Rampal L
    Cancer Causes Control, 1992 Mar;3(2):179-82.
    PMID: 1562708 DOI: 10.1007/BF00051659
    Nasopharyngeal carcinoma (NPC) is one of the most common cancers in Malaysia, a country in Southeast Asia with a multiracial population. While hospital-based data on NPC and data from a few states have been reported, a comprehensive study involving every known NPC patient in the whole of Peninsular Malaysia in one particular year had never been done. In the present study, the computed incidence rate was not only adjusted for age, sex, ethnicity, and place of residence, but also direct standardization methods of Rothman and Dever were used to reduce any distortion. The mean age of the 365 new cases of NPC registered in 1988 was 46.8 years (SD +/- 12.2 years). The ages of patients ranged from 10 to 80 years. The incidence in both sexes rose after the age of 20-29 years and reached a plateau between 40 and 49 years. No further rise was exhibited after age 60 years. The Chinese had the highest age-adjusted incidence rates, particularly for the age group 40-49 years, where the incidence rate was 40.1 per 100,000 for males and 14.9 for females. The average age-adjusted male/female ratio was 2.8:1. Age-adjusted incidence varied by place of residence. The pattern that emerged from the data indicated the possibility of interaction between genetic susceptibility and environmental cofactors in the etiology of NPC.
  15. Cheng HM, Foong YT, Mathew A, Sam CK, Dillner J, Prasad U
    J Virol Methods, 1993 Apr;42(1):45-51.
    PMID: 7686558
    An ELISA using the Epstein-Barr virus nuclear antigen 1 (EBNA 1) was found to detect selectively specific IgA in sera from patients with nasopharyngeal carcinoma (NPC). The antigen, p107, was a 20-amino acid synthetic peptide, representing a major epitope of EBNA 1.267/294 (90.8%) of NPC patients had IgA antibodies to p107 but in normal individuals, only 41/577 (7.1%) had IgA/p107. In sera from patients with other cancers, 11/77 (14.3%) had IgA/p107 reactivity. 124 IgA/VCA positive and 86 IgA/VCA negative NPC sera were also tested for IgA/p107 binding in ELISA. The majority of IgA/VCA positive sera (117) also contained IgA/p107 antibodies. Of interest was the detection of 74/86 IgA/p107 reactive sera in the IgA/VCA negative group. The results suggest that the IgA/p107 ELISA could become a useful, complementary screening assay to the IgA/VCA immunofluorescence test for detection of NPC.
  16. Se Thoe SY, Wong KK, Pathmanathan R, Sam CK, Cheng HM, Prasad U
    Gynecol Oncol, 1993 Aug;50(2):168-72.
    PMID: 8397152
    Epstein-Barr virus (EBV) receptors (EBV/C3d receptors) were detected, using the monoclonal antibody HB5, on 23 ectocervical and 5 endocervical biopsies of the uterine cervix. Elevated IgA titers against the viral capsid antigen and early antigen of EBV were also found in the cervical secretions from cervical carcinoma patients (83%), compared with samples from patients with cervical intraepithelial neoplasia (75%), herpes simplex virus-infected patients (0%), and gynecologic patients with nonmalignant conditions (0%). EBV DNA was present in 63% of cervical carcinoma biopsies detected by in situ hybridization. These observations suggest a positive association between EBV and carcinoma of the cervix.
  17. Mathew A, Cheng HM, Sam CK, Joab I, Prasad U, Cochet C
    Cancer Immunol Immunother, 1994 Jan;38(1):68-70.
    PMID: 8299121
    The BamHI Z EBV replication activator (ZEBRA) protein is involved in the switch from latency to productive cycle of Epstein-Barr virus. A recombinant ZEBRA protein was synthesized and assessed in enzyme-linked immunosorbent assay (ELISA) for serum IgG response in nasopharyngeal carcinoma (NPC) patients. In 100 NPC serum samples that were positive for IgA to the EBV viral capsid antigen (VCA), 75% had IgG anti-ZEBRA antibodies. In contrast, only 3/83 (3.6%) serum samples from healthy donors and 2/50 (4%) from other cancers were positive for IgG to ZEBRA. Interestingly, in a selected group of 100 NPC sera negative for IgA to VCA, 25% contained IgG anti-ZEBRA antibodies. This suggests that the ELISA for IgG anti-ZEBRA may also identify earlier cases of NPC not detected by the conventional immunofluorescence test for IgA to VCA.
  18. Mathew A, Cheng HM, Sam CK, Prasad U
    Clin. Immunol. Immunopathol., 1994 May;71(2):164-8.
    PMID: 7514112
    Inhibition studies were carried out to study possible cross-reactivity between a peptide fragment of the Epstein-Barr virus nuclear antigen, EBNA-1, and keratin/collagen. The 20-amino acid peptide (pAG), derived from a glycine-alanine repeat region of EBNA-1, uniquely makes up about one-third of the viral protein and is a dominant IgA antigenic epitope in patients with nasopharyngeal carcinoma (NPC). A small percentage of normal human sera (NHS) also binds pAG and this reactivity is examined in this study. Ten percent (2/20) and 13.4% (2/15) of IgA-pAG-positive NPC sera and NHS, respectively, were significantly inhibited by keratin in a competitive ELISA system. Conversely, 31.6% (6/19) and 30.8% (4/13) of IgA-keratin-positive NPC sera and NHS, respectively, were significantly inhibited by pAG. This indicated minimum cross-reactivity between IgA serum antibodies to EBNA-1 and keratin. Using collagen as inhibitor, none of 18 and only 2/13 IgA-pAG-positive NPC sera and NHS, respectively, were inhibited. In the collagen ELISA system, only 2/19 (10.5%) and 4/25 (16%) of IgA-collagen-positive NPC sera and NHS, respectively, were inhibited with pAG. Therefore, cross-reactivity with collagen was also low. IgA-pAG-positive NHS may therefore not be a false positive phenomenon, but whether it may represent an early serological profile related to NPC carcinogenesis remains to be determined.
  19. Sam CK, Abu-Samah AJ, Prasad U
    Eur J Surg Oncol, 1994 Oct;20(5):561-4.
    PMID: 7926060
    Titers of IgA/VCA from 92 nasopharyngeal carcinoma (NPC) patients were monitored for 3 to 11 years from the time of diagnosis. The fluctuations in the IgA/VCA titers during follow-up did not correlate with the clinical status of the patients, suggesting that IgA/VCA is of marginal significance in the monitoring of NPC patients during follow-up. In addition, the frequency of recurrence of NPC was independent of presence or absence of elevated IgA/VCA at diagnosis.
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