Interaction of the phospholipid scramblase 1 with HIV-1 Tat results in the repression of Tat-dependent transcription.

Human phospholipid scramblase 1 (PLSCR1) is an interferon (IFN)-stimulated gene and possesses an IFN-mediated antiviral function. We show here that PLSCR1 directly interacts with human immunodeficiency virus type-1 (HIV-1) Tat. This interaction occurs both in vitro and in vivo through amino acids 160-250 of PLSCR1. Overexpression of PLSCR1 efficiently represses the Tat-dependent transactivation of the HIV-1 long terminal repeat (LTR) and reduces the nuclear translocation of Tat. In addition, shRNA-mediated suppression of endogenous PLSCR1 expression enhances the levels of gag mRNA in an HIV-1-infected T-cell line. These findings indicate that PLSCR1 negatively regulates the Tat-dependent transactivation of the HIV-1 LTR during HIV-1 infection.

Development of ultra-super sensitive immunohistochemistry and its application to the etiological study of adult T-cell leukemia/lymphoma.

Antigen retrieval (AR) and ultra-super sensitive immunohistochemistry (ultra-IHC) have been established for application to archival human pathology specimens. The original ultra-IHC was the ImmunoMax method or the catalyzed signal amplification system (ImmunoMax/CSA method), comprising the streptavidin-biotin complex (sABC) method and catalyzed reporter deposition (CARD) reaction with visualization of its deposition. By introducing procedures to diminish non-specific staining in the original ultra-IHC method, we developed the modified ImmunoMax/CSA method with AR heating sections in an AR solution (heating-AR). The heating-AR and modified ImmunoMax/CSA method visualized expression of the predominantly simple present form of HTLV-1 proviral DNA pX region p40Tax protein (Tax) in adult T-cell leukemia/lymphoma (ATLL) cells in archival pathology specimens in approximately 75% of cases. The simple present form of Tax detected exhibited a close relation with ATLL cell proliferation. We also established a new simplified CSA (nsCSA) system by replacing the sABC method with the secondary antibody- and horse radish peroxidase-labeled polymer reagent method, introducing the pretreatments blocking non-specific binding of secondary antibody reagent, and diminishing the diffusion of deposition in the CARD reaction. Combined with AR treating sections with proteinase K solution (enzymatic-AR), the nsCSA system visualized granular immunostaining of the complex present form of Tax in a small number of ATLL cells in most cases, presenting the possibility of etiological pathological diagnosis of ATLL and suggesting that the complex present form of Tax-positive ATLL cells were young cells derived from ATLL stem cells. The heating-AR and ultra-IHC detected physiological expression of the p53 protein and its probable phosphorylation by Tax in peripheral blood mononuclear cells of peripheral blood tissue specimens from HTLV-1 carriers, as well as physiological and pathological expression of the molecules involved with G1 phase progression and G1-S phase transition (E2F-1, E2F-4, DP-1, and cyclin E) in ATLL and peripheral T-cell lymphoma cells. The ultra-IHC with AR is useful for etiological pathological diagnosis of ATLL since HTLV-1 pathogenicity depends on that of Tax, and can be a useful tool for studies translating advanced molecular biology and pathology to human pathology.

Enhanced Autophagy and Reduced Expression of Cathepsin D Are Related to Autophagic Cell Death in Epstein-Barr Virus-Associated Nasal Natural Killer/T-Cell Lymphomas: An Immunohistochemical Analysis of Beclin-1, LC3, Mitochondria (AE-1), and Cathepsin D in Nasopharyngeal Lymphomas.

This study investigated autophagy in 37 cases of nasopharyngeal lymphomas including 23 nasal natural killer (NK)/T-cell lymphomas (NKTCL), 3 cytotoxic T-cell lymphomas (cytotoxic-TML) and 9 B-cell lymphomas (BML) by means of antigen-retrieval immunohistochemistry of beclin-1, LC3, mitochondria (AE-1) and cathepsin D. Peculiar necrosis was noted in EBV(+) lymphomas comprising 21 NKTCL, 2 cytotoxic-TML and 1 BML. Lymphomas without peculiar necrosis showed high expression of beclin-1, macrogranular cytoplasmal stain of LC3 with sporadic nuclear stain, a hallmark of autophagic cell death (ACD), some aggregated mitochondria and high expression of cathepsin D, suggesting a state of growth with enhanced autophagy with sporadic ACD. EBV(+) NKTCL with the peculiar necrosis, showed significantly low level of macrogranular staining of LC3, aggregated mitochondria and low expression of cathepsin D in the cellular areas when degenerative lymphoma cells showed decreased beclin-1, significantly advanced LC3-labeled autophagy, residual aggregated mitochondria and significantly reduced expression of cathepsin D, suggesting advanced autophagy with regional ACD. Consequently it was suggested that enhanced autophagy and reduced expression of lysosomal enzymes induced regional ACD under EBV infection in NKTCL.

Human I-mfa domain proteins specifically interact with KSHV LANA and affect its regulation of Wnt signaling-dependent transcription.

Kaposi's sarcoma-associated herpes virus (KSHV)-encoded latency-associated nuclear antigen (LANA) protein has been reported to interact with glycogen synthase kinase 3beta (GSK-3beta) and to negatively regulate its activity, leading to stimulation of GSK-3beta-dependent beta-catenin degradation. We show here that the I-mfa domain proteins, HIC (human I-mfa domain-containing protein) and I-mfa (inhibitor of MyoD family a), interacted in vivo with LANA through their C-terminal I-mfa domains. This interaction affected the intracellular localization of HIC, inhibited the LANA-dependent transactivation of a beta-catenin-regulated reporter construct, and decreased the level of the LANA.GSK-3beta complex. These data reveal for the first time that I-mfa domain proteins interact with LANA and negatively regulate LANA-mediated activation of Wnt signaling-dependent transcription by inhibiting the formation of the LANA.GSK-3beta complex.

Novel anticytomegalovirus activity of immunosuppressant mizoribine and its synergism with ganciclovir.

Cytomegalovirus (CMV) infection is a prominent infection in transplant recipients. The immunosuppressive drug mizoribine was shown to have anti-CMV activity in vitro and was reported to have an anti-CMV effect in renal transplantation. This study characterized the anti-CMV activity of mizoribine in vitro and its synergistic activity with ganciclovir. Mizoribine suppressed replication and at the EC(50) for plaque inhibition of 12.0 microg/ml. Mizoribine and ganciclovir exerted a strong synergism in anti-CMV activity. Mizoribine depletes guanosine nucleotides by inhibiting inosine monophosphate dehydrogenase and may increase the ratio of ganciclovir to guanosine in treated cells, resulting in a strong synergistic augmentation of the anti-CMV activity of ganciclovir. Two clinical isolates with UL97 mutations were less susceptible to mizoribine than the Towne strain but were equally susceptible in the presence of guanine. Two mizoribine-resistant strains were isolated after culture for 3 months with 100 microg/ml mizoribine, but they were as sensitive to ganciclovir as the parent Towne strain. The anti-CMV activity of mizoribine was antagonized by 2'-deoxyguanosine. Mizoribine inhibited CMV replication directly, and the sequence of mizoribine-resistant mutants of UL97 and UL54 was identical to that of the parent Towne strain, indicating the different anti-CMV action from ganciclovir, foscarnet, and maribavir. Mizoribine as an immunosuppressive and anti-CMV drug in the clinical regimen was suggested to suppress replication of CMV in vivo and control CMV infection in transplant recipients in combination with ganciclovir.

UL146 variability among clinical isolates of human cytomegalovirus from Japan.

Human cytomegalovirus (HCMV) is a herpesvirus associated with serious diseases in immunocompromised subjects. The region between ORF UL133 and UL151 from HCMV, named ULb' is frequently deleted in attenuated AD169 and in highly passaged laboratory strains. However, this region is conserved in low-passaged and more virulent HCMV, like the Toledo strain. The UL146 gene, which is located in the ULb' region, encodes a CXC-chemokine analogue. The diversity of UL146 gene was evaluated among fifty-six clinical isolates of HCMV from Japan. Results show that UL146 gene was successfully amplified by the polymerase chain reaction (PCR) in only 17/56 strains (30%), while the success rate for UL145/UL147 gene was 18/56 strains (32%). After DNA sequencing, the 35 amplified strains were classified into 8 groups. When compared, variability of UL146 ranged from 25.1% to 52.9% at the DNA level and from 34.5% to 67% at the amino acid level. Seven groups had the interleukin-8 (IL-8) motif ERL (Glu-Leu-Arg) CXC and one group had only the CXC motif, suggesting the absence of the IL-8 function of UL146. In conclusion, we found that UL146 gene of HCMV is hyper-variable in clinical strains from Japan suggesting the possibility of a different function in each sequence group.

[Clonal expansion and genomic characterization of the human T-cell lymphotropic virus type I during the integration process in adult T-cell leukemia/lymphoma]. / Expansión clónica y caracterización genómica del proceso de integración del virus linfotrópico humano tipo I en la leucemia/linfoma de células T en adultos.

INTRODUCTION: Although the integration of human T-cell lymphotropic virus type I into the T-cells is not a random process, the mechanistic details are not understood. OBJECTIVES: The characteristics of the flanking host chromatin were evaluated at the integration sites in adult T-cell leukaemia/lymphoma (ATLL) patients infected with the virus. MATERIALS AND METHODS: From seven leukemic Colombian patients positive for the human T-cell lymphotropic virus type I (HTLV-I), lymphocyte DNA samples were extracted and amplified by inverse polymerase chain reaction (IPCR). Clonal expansion and human genome nucleotide composition in an extension of 50 bp was determined. To establish the characteristics of the human genome flanking provirus, 61 IPCR sequences from Colombian and Japanese ATLL patients, were analyzed in silico to obtain insights about the genomic structure, functions and nature of associated chromatin. RESULTS: The clonal expansion of cell clones was predominantly oligoclonal. From 61 IPCR sequences, 155 alignments with homology higher than 95% (e-value < 0.05) were screened. Seventy-five percent of those sequences corresponded to non coding elements that include repetitive and non-repetitive DNA. Fifty percent of the proviral integrations were associated with chromosomes of A and B groups. Viral DNA integration tended to favor exons of genes that replicated early, controlled the cell cycle, or were involved in signal transduction. CONCLUSIONS: The results indicated that HTLV-I integration was preferentially directed towards genomic environments with high C:G content, and toward genes that replicate early, regulate cell cycle or involved with signal transduction.

Epstein-Barr virus associated gastric carcinoma: epidemiological and clinicopathological features.

In this paper, the roles of Epstein-Barr virus (EBV) in gastric carcinogenesis are discussed, reviewing mainly epidemiological and clinicopathological studies. About 10% of gastric carcinomas harbor clonal EBV. LMP1, an important EBV oncoprotein, is only rarely expressed in EBV-associated gastric carcinoma (EBV-GC) while EBV-encoded small RNA is expressed in almost every EBV-GC cell, suggesting its importance for developing and maintaining this carcinoma. In addition, the hypermethylation-driven suppressor gene downregulation, frequently observed in EBV-GC, appears to give a selective advantage for carcinoma cells. EBV reactivation is suspected to precede EBV-GC development since antibodies against EBV-related antigens, including EBV capsid antigen (VCA), are elevated in prediagnostic sera. Interestingly, the average anti-VCA immunoglobulin G antibody titer in EBV-GC patients was significantly higher among men than among women, whereas EBV-negative GC cases did not show such a sex difference. A higher frequency of human leucocyte antigen-DR11 in EBV-GCs suggests that major histocompatibility complex-restricted EBV nuclear antigen 1 epitope recognition may enhance EBV reactivation. EBV infection of gastric cells by lymphocytes with reactivated EBV is suspected to be the first step of EBV-GC development. Male predominance of EBV-GC suggests the involvement of lifestyles and occupational factors common among men. The predominance of EBV with XhoI+ and BamHI type i polymorphisms in EBV-GC in Latin America suggests a possibility of some EBV oncogene expressions being affected by EBV polymorphism. The lack of such predominance in Asian countries, however, indicates an interaction between EBV polymorphism and the host response. In conclusion, further studies are necessary to examine the interaction between EBV infection, its polymorphisms, environmental factors, and genetic backgrounds.

Epstein-Barr virus-associated primary lymphoepitheliomalike carcinoma of the esophagus.

Primary lymphoepitheliomalike carcinomas (LELC) of the esophagus are uncommon, with only 29 previously reported cases in the literature. Primary LELC of the esophagus is associated with Epstein-Barr virus (EBV). We herein report a 52-year-old man who presented with dysphagia and weight loss and was found to have a polypoid mass in the middle esophagus. Pathologic examination showed LELC. EBV infection was demonstrated by immunohistochemical detection of EBNA-1 in neoplastic cells and polymerase chain reaction amplification for EBNA-3C, BamHI-F, and W1/I1 regions but not by in situ hybridization by EBER-1 transcripts. EBV genotyping analysis demonstrated infection by a novel type "i"/XhoI loss recombinant strain. Although it is accepted that polymorphisms at BamHI-W1/I1 region cosegregate with polymorphisms at XhoI restriction site, this novel recombinant EBV has been identified in healthy donors and in nasal NK/T-cell lymphoma. To our knowledge, this is the first report that describes this recombinant type "i"/XhoI loss EBV strain in a primary LELC of the esophagus.

Anticytomegalovirus activity of pristimerin, a triterpenoid quinone methide isolated from Maytenus heterophylla (Eckl. & Zeyh.).

We examined the anticytomegalovirus properties of four compounds: pristimerin, the pristimerin analogue, lupeol and 2-acetylphenol-1-beta-D-glucopyranosyl (1 --> 6)-beta-D-xylpyranoside (acetophenol glycoside), isolated from Maytenus heterophylla, a Kenyan medicinal plant. The effects were studied on human cytomegalovirus (HCMV) replication in the human embryonic fibroblast cell line, MRC-5. In a viral plaque-reduction assay, pristimerin showed dose-dependent inhibitory properties with a 50% inhibitory concentration of 0.53 microg/ml (selective index = 27.9). The cells treated with pristimerin inhibited the cytopathic effects in HCMV-infected cells. Moreover, pristimerin suppressed viral replication without affecting the cell growth. Pristimerin inhibited the synthesis of viral DNA but had no virucidal effect on cell-free HCMV. Furthermore, Western blot analysis demonstrated that pristimerin decreased the amount of immediate early (IE) antigen (especially IE2) expression in the infected cells. These results suggest that pristimerin is a unique compound with potential anti-HCMV activity.

E-cadherin and beta-catenin expression in Epstein-Barr virus-associated gastric carcinoma and their prognostic significance.

AIM: To examine the role of E-cadherin and beta-catenin in carcinogenesis and to assess their prognostic implication in Epstein-Barr virus-associated gastric carcinomas (EBV-GCs). METHODS: We compared the frequency of E-cadherin and beta-catenin expression in 59 EBV-GCs and 120 non-EBV-GCs, and examined the association between patients' prognosis and the expressions of these proteins. RESULTS: Neither the cellular-membranous nor the cytoplasmic E-cadherin expression showed any difference between EBV-GCs and non-EBV-GCs. On the other hand, loss of membranous expression of beta-catenin occurred more frequently in non-EBV-GCs than EBV-GCs [odds ratio = 0.41; 95% confidence interval (CI), 0.19-0.90]. Furthermore, the nuclear and/or cytoplosmic expression of beta-catenin was seen more frequently in EBV-GCs than non-EBV-GCs (odds ratio = 2.23; 95% CI, 0.97-5.09), and was observed in a larger proportion of carcinoma cells of EBV-GCs than non-EBV-GCs (P = 0.024). Survival analysis for non-EBV-GC revealed that lymph node metastasis was significantly associated with poor prognosis (P < 0.001). Among EBV-GCs, the depth of invasion (P = 0.005), lymph node metastasis (P = 0.004) and an intestinal type by Lauren classification (hazard ratio = 9.47; 95% CI, 2.67-33.6) were significantly associated with poor prognosis. On the other hand, nuclear and/or cytoplasmic expression of beta-catenin was associated with a better prognosis in patients with EBV-GC (hazard ratio = 0.32; 95% CI, 0.11-0.93). CONCLUSION: We observed more frequent preservation of beta-catenin in cell membrane and accumulation in nuclei and/or cytoplasm in EBV-GCs than in non-EBV-GCs. Factors involved in the prognosis of EBV-GCs and non-EBV-GCs are different in the two conditions.

Inhibition of ganciclovir-resistant human cytomegalovirus replication by Kampo (Japanese herbal medicine).

We examined the effect of Kampo on the replication of ganciclovir (GCV)-resistant human cytomegalovirus (HCMV) in the human embryonic fibroblast cell line MRC-5. Treatment of HCMV-infected cells with Sho-seiryu-to (SST; Xiao-Qing-Long-Tang in Chinese) resulted in the inhibition of viral replication without affecting the cell growth. SST treatment decreased the synthesis of viral DNA, but had no virucidal effect on cell-free HCMV. However, the inhibitory effect of SST on HCMV replication was ablated by anti-interferon-beta (IFN-beta) antibody suggesting that SST inhibits the replication of GCV-resistant HCMV through the induction of IFN-beta. These results suggest that SST is a novel compund with potential as an anti-HCMV.

Human papillomavirus in lung carcinomas among three Latin American countries.

The presence of human papillomavirus (HPV) genome in lung carcinomas has been reported worldwide but its frequency varies from country to country. We examined HPV genome in 36 lung carcinomas, consisting of 14 squamous cell carcinomas, 13 adenocarcinomas, and 9 small cell carcinomas, collected from Colombia, Mexico and Peru. PCR analysis using GP5+/GP6+ primers, combined with Southern blot hybridization, found the presence of HPV genome in 10 (28%) of 36 cases. This percentage is similar to the value of 22% reported by Syrjänen, who conducted a meta-analysis of nearly 2500 lung carcinomas examined to date. Genotype analysis revealed that the most predominant genotype was HPV-16 (7 cases), followed by HPV-18 (2 cases) and HPV-33 (1 case). HPV-16 was more frequently found among female than male cases (P=0.008) but was not detected in any adenocarcinoma cases. On the other hand, HPV-18 and HPV-33 were detected only among male cases. These HPV genotypes were detected only in adenocarcinomas, and all the HPV genotypes detected in this histological type were HPV-18 or HPV-33. The frequency of HPV-16 positive cases among all the HPV positive cases differed in the sexes (P=0.033) and differed in the three histological types (P=0.017). The presence of HPV tended to be more frequent in well-differentiated tumors when squamous cell carcinomas and adenocarcinomas were combined. However, it was not statistically significant (P=0.093). Neither p16 nor p53 expression in carcinoma cells was related to the proportion of HPV-positive cases. In conclusion, high-risk HPV DNA was detected in 28% of lung carcinomas. The predisposition of HPV-16 to female cases and to non-adenomatous carcinomas warrants further investigation.

Human papillomavirus in esophageal squamous cell carcinoma in Colombia and Chile.

AIM: To examine the presence of human papillomavirus (HPV) in esophageal squamous cell carcinoma (ESCC) specimens collected from Colombia and Chile located in the northern and southern ends of the continent, respectively. METHODS: We examined 47 and 26 formalin-fixed and paraffin-embedded ESCC specimens from Colombia and Chile, respectively. HPV was detected using GP5+/GP6+ primer pair for PCR, and confirmed by Southern blot analysis. Sequencing analysis of L1 region fragment was used to identify HPV genotype. In addition, P16(INK4A) protein immunostaining of all the specimens was conducted. RESULTS: HPV was detected in 21 ESCC specimens (29%). Sequencing analysis of L1 region fragment identified HPV-16 genome in 6 Colombian cases (13%) and in 5 Chilean cases (19%). HPV-18 was detected in 10 cases (21%) in Colombia but not in any Chilean case. Since Chilean ESCC cases had a higher prevalence of HPV-16 (without statistical significance), but a significantly lower prevalence of HPV-18 than in Colombian cases (P = 0.011) even though the two countries have similar ESCC incidence rates, the frequency of HPV-related ESCC may not be strongly affected by risk factors affecting the incidence of ESCC. HPV-16 genome was more frequently detected in p16 positive carcinomas, although the difference was not statistically significant. HPV-18 detection rate did not show any association with p16 expression. Well-differentiated tumors tended to have either HPV-16 or HPV-18 but the association was not statistically significant. HPV genotypes other than HPV-16 or 18 were not detected in either country. CONCLUSION: HPV-16 and HPV-18 genotypes can be found in ESCC specimens collected from two South American countries. Further studies on the relationship between HPV-16 presence and p16 expression in ESCC would aid understanding of the mechanism underlying the presence of HPV in ESCC.

Environmental factors related to gastric cancer associated with Epstein-Barr virus in Colombia.

Epstein-Barr virus (EBV)-encoded small RNA can be detected in about 1-17 % of gastric carcinomas. To elucidate lifestyles and other factors related to such an EBV-associated gastric carcinoma (EBV-GC), we conducted a case-control study in Cali, Colombia. The study subjects were 368 patients with gastric carcinoma newly diagnosed during the period between September 2000 and June 2003, including 42 EBV-GC cases. We obtained information on lifestyles, dietary habits, and occupational exposure by a questionnaire. The frequency of EBV-GC was related to birth order of patients (P for trend =0.025). More precisely, EBV-GC was much less frequent among the patients who were the eldest child in a family (P=0.007). Those findings were contrary to what was reported by the study conducted in Japan, where EBV-GC was more frequently observed among eldest brothers/sisters. A possible explanation for the apparently conflicting results is that EBV-GC risk is related to the age at first EBV infection but its relationship is not monotonic. In addition to the relationship with birth order, the present study showed that high salt intake and metal dust exposure may be related to EBV-GC as reported by the Japanese study although these associations observed in the present study were not statistically significant. No significant association was observed in other factors, including dietary habits. Further studies seem warranted to elucidate the difference between Japan and Colombia with respect to the environmental factors related to EBV-GC cases.

Autocrine growth of Epstein-Barr virus-positive gastric carcinoma cells mediated by an Epstein-Barr virus-encoded small RNA.

Although 5-10% of gastric carcinoma (GC) cases worldwide are associated with EBV, a human herpesvirus, it is still not clear what the precise contribution of the virus is to the pathogenesis of EBV-positive GC. Here we report that EBV infection induces expression of insulin-like growth factor 1 (IGF-I) in the GC-derived EBV-negative cell line NU-GC-3 and that the secreted IGF-I acts as an autocrine growth factor. Transfection of individual EBV latent genes into NU-GC-3 cells revealed that the EBV-encoded small RNA (EBER) was responsible for IGF-I expression. Addition of recombinant IGF-I accelerated growth of NU-GC-3 cells, whereas growth of the EBV-converted NU-GC-3 cells was blocked by treatment with an anti-IGF-I antibody. These results suggest that IGF-I induced by EBER acts as an autocrine growth factor for EBV-positive GC. These findings seem to be operative in vivo, as EBV-positive GC biopsies consistently express IGF-I, whereas EBV-negative GC biopsies do not. EBER is invariably expressed in EBV-associated malignancies including GC. The present findings strongly suggest that EBV directly affects the pathogenesis of EBV-positive GC and underline the importance of RNA molecules on cell growth regulation.

Epstein-Barr virus-associated gastric carcinoma: Evidence of age-dependence among a Mexican population.

AIM: To investigate features of Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) among a Mexican population. METHODS: Cases of primary gastric adenocarcinoma were retrieved from the files of the Departments of Pathology at the Instituto Nacional de Cancerologia and the Instituto Nacional de la Nutricion in Mexico City. The anatomic site of the gastric neoplasia was identified, and carcinomas were histologically classified as intestinal and diffuse types and subclassified as proposed by the Japanese Research Society for Gastric Cancer. EBV-encoded small non-polyadenylated RNA-1 (EBER-1) in situ hybridization was conducted to determine the presence of EBV in neoplastic cells. RESULTS: We studied 330 consecutive, non-selected, primary gastric carcinomas. Among these, there were 173 male and 157 female patients (male/female ratio 1.1/1). EBER-1 was detected in 24 (7.3%) cases (male/female ratio: 1.2/1). The mean age for the entire group was 58.1 years (range: 20-88 years), whereas the mean age for patients harboring EBER-1-positive gastric carcinomas was 65.3 years (range: 50-84 years). Age and histological type showed statistically significant differences, when EBER-1-positive and -negative gastric carcinomas were compared. EBER-1 was detected in hyperplastic- and dysplastic-gastric mucosa surrounding two EBER-1-negative carcinomas, respectively. CONCLUSION: Among Latin-American countries, Mexico has the lowest frequency of EBVaGC. Indeed, the Mexican population >50 years of age was selectively affected. Ethnic variations are responsible for the epidemiologic behavior of EBVaGC among the worldwide population.

[New antivirals for herpesviruses].

The long-term treatment of herpesvirus infections with current antivirals leads to the development of drug-resistant viruses. Because currently available antivirals finally target the viral DNA polymerase, mutant resistant to one drug often shows cross-resistance to other drugs. This evidence highlights the need for the development of new antivirals that have the different viral targets. Recently, high-through-put screening of large compound collections for inhibiting specific viral enzymes, or in vitro cell culture assay, has identified several new antivirals. These include the inhibitors of helicase/primase complex, terminase complex, portal protein and UL97 protein kinase. This review will focus on these new compounds that directly inhibit viral replication.

The comparison of the prognosis between Epstein-Barr virus (EBV)-positive gastric carcinomas and EBV-negative ones.

The relationship between the degree of lymphocytic infiltration into the tumor and the prognosis has not been completely evaluated between Epstein-Barr virus (EBV)-positive and -negative gastric carcinoma (GC). Although the average numbers and the grades of the infiltrating CD8+T cells, natural killer cells, dendritic cells, Ki67-positive cells were significantly greater in EBV-positive GCs than in -negative GCs, there was no significant survival improvement in EBV-positive group. These findings suggest that the infiltration of lymphocytes in the EBV-positive GC does not necessarily meant better prognosis and that the EBV status is not a significant prognostic factor in the patients with gastric cancer.

Envelope sequence variation and phylogenetic relations of human T cell lymphotropic virus type 1 from endemic areas of Colombia.

The HTLV-1 envelope gene of 12 TSP/HAM patients from two endemic areas of southwest Colombia (Tumaco and Buenaventura) was amplified by nested PCR, sequenced, and compared with previously reported HTLV-1 envelope sequences from isolates worldwide. In general, the sequence divergences among all Colombian samples ranged from 0.1 to 1.6%. Some amino acid substitutions, referring to the ATK-1 prototype strain in the surface domain gp46 and in p21, were highly prevalent in southwest Colombia, suggesting a geographical clustering of mutations in the envelope gene. The phylogenetic analysis showed that the Colombian isolates belong to the HTLV-1a lineage with minor subgroups. The genetic distance between Colombian and Japanese isolates ranged from 0.1 to 1.8%; in comparison, the genetic distance between Colombian and Caribbean isolates ranged from 0.4 to 2.2%. Our results strongly suggest that the actual quasispecies populations in southwest Colombia have been generated by separate, differently timed introductions of virus.