Epstein-Barr virus DNA in nasopharyngeal carcinoma in Thai patients at Ramathibodi Hospital, Bangkok.

Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in Thailand. The association of Epstein-Barr virus (EBV) and NPC, especially undifferentiated type, has been documented. There is, however, conflicting evidence with regard to the squamous cell type. We have therefore investigated EBV-DNA in all the three types of NPC to assess the association of EBV and NPC in Thai patients. EBV-DNA was detected in formalin-fixed paraffin-embedded tissues from the patients of Ramathibodi Hospital, Bangkok using polymerase chain reaction. A primer pair that amplified EBV nuclear antigen gene was used in the reactions and the amplification products were hybridized with a specific EBV probe. EBV-DNA was identified in 24 of 28 of tissue samples from patients with undifferentiated NPC, 25 of 40 samples from patients with squamous cell NPC and 3 of 4 samples with nonkeratinizing NPC. None of 12 nasopharyngeal tissue samples without NPC contained detectable EBV-DNA. Our results indicated a strong association of EBV with undifferentiated as well as non-keratinizing NPC. EBV-DNA was demonstrated in most cases of squamous cell NPC but the association of EBV in this type of carcinoma was not as frequent as in the other two types of NPC.

Incidence of Mycoplasma pneumoniae, Chlamydia trachomatis, and viral infections in pneumonia cases under six months of age, Bangkok, Thailand.

The incidence of infections by Mycoplasma pneumoniae, Chlamydia trachomatis and respiratory viruses was investigated in 76 pneumonic patients aged under 6 months who attended Ramathibodi and Siriraj Hospitals in Bangkok during two study periods. M. pneumoniae infection was not found in any case from either hospital by serological diagnosis. By the isolation method, C. trachomatis infection was found in 7(16.7%) of 42 patients from Ramathibodi Hospital and 5(21.7%) of 23 patients from Siriraj Hospital with the average male:female ratio of 2.6:1; and 91.7% of the infected cases were under 3 months old. Laboratory diagnosis of respiratory virus infection was performed by indirect immunofluorescence (IIF), isolation, and by antibody detection. Data from Ramathibodi Hospital showed that 11 (24.4%), 4 (8.9%), 3 (6.7%) of the 45 patients were infected by respiratory syncytial virus (RSV), adenoviruses, parainfluenza virus type 3, and some other viruses, respectively; infection rates of 10 (32.3%), 4 (12.9%), 1 (3.2%) and 1 (3.2%) by those viruses respectively, were observed in the 31 patients from Siriraj Hospital.

Detection of human immunodeficiency virus type 1 (HIV-1) proviral DNA in breast milk and colostrum of seropositive mothers.

There is increasing evidence of vertical transmission of HIV-1 to infants through breast feeding of milk from HIV-1 infected mothers. It has been postulated that transmission occurs mainly via ingestion of infected cells in breast milk and colostrum. In this study, detection of HIV-1 proviral DNA was used to prove that cells from colostrum and milk do contain HIV. DNA were extracted from these cells of colostrum and milk of 18 seropositive mothers and amplified by nested PCR for HIV-1 gag and pol and 44 per cent were positive mostly by two primers. All ten negative control samples from seronegative mothers were negative. This study demonstrated the infectivity of breast milk and colostrum. Nevertheless, recommendation against breast-feeding should be weighed against poor alternatives in low socioeconomic families.