Epstein-Barr virus (EBV) preparations from both NPC-KT cells (NPC-EBV) and P3HR-1 cells (HR-1-EBV) can induce cell fusion between EBV receptor (EBVR)-positive Raji cells and EBVR-negative cells, but other strains of EBV cannot induce cell fusion. The effect of these two EBV isolates on ability of cells to fuse has been studied to determine if there are differences in the biological properties of the different EBV isolates, particularly the isolates obtained from nasopharyngeal carcinoma such as NPC-EBV. The frequency of cell fusion between NPC-EBV-superinfected Raji cells and EBVR-negative epithelial cells (Ad-AH) was increased more than 30-fold in the presence of medium containing 1% dimethylsulfoxide (DMSO). However, the frequency of cell fusion between HR-1-EBV-superinfected Raji cells and Ad-AH cells was unaffected under the same conditions. The data show that differences in the ability of cells to fuse are induced by variants of EBV in response to DMSO. These differences may be important in elucidating the different biological properties of EBV isolates and might have implications for the pathophysiology of EBV-associated illness.

The association of Epstein-Barr virus (EBV) with nasopharyngeal carcinoma (NPC) has been shown by various methods. The purpose of this study is to identify the most useful method to detect EBV in NPC. Both polymerase chain reaction (PCR) for EBV-DNA and in situ hybridization for EBV-encoded small RNAs (EBERs) were examined in formalin-fixed, paraffin-embedded NPC specimens. In situ hybridization was performed in 56 cases, and PCR for EBV-DNA was performed in 42 cases. EBV-DNA was detected in 0 of 3 keratinizing squamous cell carcinomas (KSCC), 22 of 24 nonkeratinizing carcinomas (NKC), all 13 undifferentiated carcinomas (UNPC), and 0 of 2 adenocarcinomas (AC). EBERs were detected in 0 of 5 KSCC, 30 of 32 NKC, 16 of 17 UNPC, and 0 of 2 AC. Among them, EBERs was detected in 35 of 42 cases in which PCR was also performed, 0 of 3 KSCC, 22 of 24 NKC, all 13 UNPC, and 0 of 2 AC, respectively. Both results were consistent in 40 of 42 cases. We conclude that both PCR and in situ hybridization are useful to detect EBV in NPC. In situ hybridization has a particular advantage because it can demonstrate the localization of EBV in neoplastic cells. In addition, close association of NKC and UNPC but not KSCC and AC with EBV is suggested.

Pseudoaneurysms of the extracranial carotid arteries are rarely seen following irradiation for cancers of the head and neck. We present a patient with a pseudoaneurysm of the common carotid artery following a radical neck dissection and irradiation for thyroid carcinoma 20 years earlier. Following oesophagoscopical examination, a pseudoaneurysm of the right common carotid artery ruptured into the piriform sinus. The common carotid artery was embolized with multiple coils and the bleeding was halted. The relationship between the carotid artery aneurysm and irradiation, and the treatment of carotid artery aneurysm, is discussed.

We have previously shown that guinea pig (G.P.) cells can be abortively infected with human cytomegalovirus (CMV) and that although no viral particles are formed, virusspecific early antigen is synthesized and cellular DNA is stimulated (1, 2).Recently Albrecht and Rapp described a strain of hamster embryo fibroblasts transformed by ultraviolet-irradiated CMV that was oncogenic after inoculation into weanling Syrian hamsters (3). St. Jeor and Rapp also demonstrated that human CMV stimulated cellular DNA in both permissively infected and abortively infected human fibroblast cells that had been pretreated with Iodeoxyuridine (IudR) (4). We have also previously observed that human CMV infection of human fibroblast cells induced cellular RNA synthesis (2). RNA species synthesized in infected cells included 28S, 18s ribosomal and 4s RNA. Since cellular DNA stimulation may be related to oncogenicity, it was of interest to study this system further, including studies of RNA metabolism. In this paper we provide data showing a similar stimulation of RNA in abortively infected G.P. cells, and confirm the increased synthesis of cellular DNA.Materials and Methods, Viruses. Towne, a strain of human CMV isolated in our laboratory from an infant and serially passaged on WI-38 human fibroblasts (5), was used throughout the experiments.Cells. Guinea pig cells were obtained by trypsinization of skin and muscle from 4-wkold embryos and were used between the first and twentieth culture passage levels.For some experiments, primary embryo cells were purchased from Flow Laboratories.WI-38 human diploid cells were obtained 1 Supported by Smith, Nine and French, Inc. and by USPHS research grant RR 05540 from the Division of Research Resources.from Leonard Hayflick (Stanford University). Medium. Eagle's minimal essential medium (MEM) supplemented with penicillin (100 units/ml), streptomycin (100 pg/ml) and fetal calf serum (10 % for growth or 2 7% for maintenance) was used.Infectivity assays. Viral infectivity titers were determined in tube cultures of WI-38 cells. The 50% end points were calculated by the method of Reed and Muench.Autoradiography. Two ml of MEM containing 3H-thymidine (2 pCi/ml) were replaced into infected and control petri dishes (3 cm Falcon) at the indicated times after discarding the old medium. The cultures were incubated at 37" for 1 hr. Then coverslips were rinsed twice with cold phosphate buffered saline (PBS) and fixed with Carnoy's solution.After washing with 95% alcohol, coverslips were air-dried. Emulsion was applied for autoradiography according to the dipping method.Exposure time was usually 7 days at 4". After development, the cells were stained with hemat oxylinosin.DNA and RNA analysis. Cells used for DNA and RNA studies were grown in 3 cm Falcon petri dishes and then infected with CMV at an input multiplicity of approximately 10 tissue culture infectious doses (TCID)50 per cell. After virus adsorption, the cultures were covered with 3 ml MEM containing 2 % fetal calf serum.Infected and control cultures ...

The linear form of Epstein-Barr virus (EBV) DNA has homologous direct tandem repeats of approximately 500 bp at each terminus (TR). After infection, EBV DNA circularizes via the TR to form the intracellular episomal DNA. To analyze the mechanism of the synthesis of linear DNA through possible replicative intermediates, the terminal fragments were identified in the total intracellular DNA and the covalently closed circular DNA from a productively infected cell line after induction of replication or after treatment with an inhibitor of viral DNA synthesis. These studies indicate that some of the fused terminal fragments detected in the total intracellular DNA are replication-dependent forms which are selectively excluded from the covalently closed circular fraction and are eliminated after treatment with acyclovir. The EBV terminal restriction enzyme fragments were identified in three producer cell lines, each with a characteristic number of TR in the intracellular episomal DNA. Identification of the termini in cell lines established with the three virus strains revealed that the newly transformed cell lines had a greater number of TR than did the template DNA in the producer cell line. The increase in the number of TR in progeny episomes indicates that linear DNA is produced from concatameric replicative intermediates rather than from amplified catenated circular intermediates.