PubMed Health⌕ Search

Biomedical subjects

V T Chow

Publications and source records attributed to V T Chow.

45 records · Page 3Linked to original sources
PubMed1990

Viruses and cancer, with particular focus on human papillomaviruses in neoplastic lesions of the cervix uteri.

Oncogenic viruses serve as useful experimental tools and models of cellular transformation and cancer biology. Tumour virology has made enormous contributions towards the molecular elucidation of malignancy, especially in the concept of oncogenes and anti-oncogenes. Here we consider the criteria, mechanisms and co-factors of viral carcinogenesis. Some viruses associated with cancers in man and animals are reviewed, with special focus on the role of human papillomaviruses (HPV) in cervical cancer. Southern hybridization and polymerase chain reaction (PCR) data demonstrating the presence of genital HPV types 11, 16, 18 and 31 in cervical neoplastic lesions from Singapore patients are presented. Sensitivity standardisation and specificity of the Southern and PCR techniques are emphasised. Common themes in viral oncology are highlighted, such as epidemiological associations; viral type, host and tissue specificities; transforming genetic elements; viral integration; and interaction with co-factors.

Female↗
PubMed1989

Nucleic acid hybridization and the polymerase chain reaction in biology and medicine, with special reference to the detection of human papillomaviruses.

Nucleic acid hybridization, and more recently, gene amplification by the polymerase chain reaction, have contributed immensely to the development of molecular genetics. These powerful tools have been greeted and employed with great enthusiasm, in view of their wide-ranging applications in biological research and clinical diagnosis. Here we review the basic principles and some applications of these techniques, particularly in infectious diseases and oncogenesis. In order to illustrate their use, data on specific methods as applied to the detection of human papillomaviruses is presented. Gene probe and DNA amplification technology will undoubtedly continue to provide critical molecular pathways in the biomedical research endeavour.

Gene Amplification↗
PubMed1986

Bacterial and mycotic otological infections in Singapore.

This paper describes a microbiological study of 84 young adult men with clinical otitic infections. Gram-negative aerobic bacilli were frequently isolated from these patients diagnosed as having otitis externa or chronic suppurative otitis media, of which Pseudomonas species predominated. Staphylococcus aureus, S. epidermidis and aerobic Corynebacterium species (diphtheroids) were also found. About 40% of ear infections were attributed to otomycoses, chiefly from Aspergillus species and Candida parapsilosis. Antimicrobial susceptibility testing of the bacterial isolates revealed that Pseudomonas species were generally resistant to antibiotics commonly employed in general practice: ampicillin, erythromycin, co-trimoxazole, tetracycline and cephaloridine. However, polymyxin B, gentamicin and neomycin were active against some Pseudomonas isolates. Other Gram-negative bacilli were also mainly sensitive to gentamicin, neomycin as well as co-trimoxazole. Disc diffusion and minimum inhibitory concentration studies demonstrated good activity of ceftazidime, cefoperazone, tobramycin and carbenicillin against strains of Pseudomonas species and other Gram-negative rods. Cefotaxime and cefoxitin were active against Gram-negative bacilli other than Pseudomonas species. Beta-lactamase production did not appear to be the main mechanism of resistance in these community-acquired Gram-negative bacillary isolates. The antimicrobial therapy of otological infections is reviewed.

Adult↗
PubMed1986

A recent epidemic of Coxsackie virus type A24 acute haemorrhagic conjunctivitis in Singapore.

A recent epidemic of acute conjunctivitis in Singapore showed again the importance of Coxsackie virus type A24 variant as a causative agent of acute haemorrhagic conjunctivitis (AHC). Although the ocular manifestations appeared similar to those described for the 1970 and 1975 outbreaks, a markedly higher rate of respiratory involvements was noted. Not observed in previous epidemics were herpes-like vesicles in the conjunctiva and eyelids of one patient and vesicles in the buccal mucosa and lips of another from whom Coxsackie virus A24 was isolated. The most interesting finding in this study was the isolation of five wild (non-Sabin) poliovirus type 1 strains. Three strains were obtained from conjunctival and two from throat swabs of patients with mild to severe conjunctivitis. It is conceivable that the rare reports of polio-like paralysis or radiculomyelitis accompanying or following AHC in a few Asian countries could be attributed to concurrent infections with a poliovirus and either enterovirus type 70 or Coxsackie virus type A24.

Adolescent↗
PubMedDate not supplied

Subclinical human papillomavirus infection of the male lower genital tract: colposcopy, histology and DNA analysis.

In 25 partners of women with genital human papillomavirus (HPV) infection or cervical intraepithelial neoplasia, colposcopic examination revealed the existence of subclinical HPV infection of the male lower genital tract in 22 cases. It manifested either as short papillae tipped with acetowhite changes, or flat acetowhite lesions on the foreskin, glans, periurethral region, scrotum, perineum and/or perianal region. Multiple lesions involving several anogenital areas were common. Some of these abnormalities were small and inconspicuous. Of these 22 cases, 17 had histological evidence of HPV infection. Although Southern blot hybridization detected HPV DNA in only one case, polymerase chain reaction (PCR) analysis revealed HPV DNA in 20 cases. There were 10 cases of HPV 16. Subclinical HPV disease is best identified by colposcopy and confirmed by PCR. In treating HPV disease, colposcopic recognition of subclinical HPV disease forms an essential part of the management plan.

Biopsy↗
PubMedDate not supplied

The third zinc finger of the WT1 gene is mutated in Wilms' tumour but not in a broad range of other urogenital tumours.

Aberrations in the WT1 tumour suppressor gene have been documented in a fraction of Wilms' tumours (WTs). Encoding a protein with four zinc fingers, the WT1 gene is expressed in the developing kidney, gonads, uterus, spleen, mesothelium and brain. Using polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing, we analysed 156 diverse tumours for abnormalities of zinc finger 3 (ZF3), a mutational hotspot in WT1. Only one sample (WT) exhibited PCR-SSCP mobility shift. A CGA to TGA nonsense mutation at codon 390 with arginine being substituted with a stop codon was detected and predicted to encode a faulty WT1 protein in this WT, out of 8 WTs studied. Our results are consistent with the presence of WT1 ZF3 mutations in a subset of WTs, but not in other tumours of urogenital nor of WT1-related origin.

Base Sequence↗