Toll-like receptors (TLRs) play pivotal roles in the innate immune system and control inflammatory responses and adaptive immunity. We previously evaluated associations between TLR7 and TLR8 gene SNPs and susceptibility to hepatitis C virus (HCV) infection. Our results suggested that TLR7IVS2-151G and TLR8-129G alleles were present at higher frequency in males of an HCV-infected group as compared to a control group (24.1% vs. 14.4%, p = 0.028; 17.6% vs. 6.8%, p = 0.004, respectively). Based upon their recognition of single stranded viral RNA, this suggested that TLR7 and TLR8 played a significant role in anti-HCV immune responses. Here, we studied the functional effects of these polymorphisms by analyzing the mRNA expressions of TLR7 and TLR8 and cytokine production induced ex vivo by TLR7- and TLR8-specific agonists using whole blood of subjects with different genotypes. The percentage of CD14+ cells from those with an AG haplotype that expressed TLR7 and TLR8 was significantly lower, but higher in intensity compared to cells from those with GG and AC haplotypes. Cells from those with an AG haplotype produced more IFN-α and less amounts of pro-inflammatory cytokines upon stimulation. This suggests that variations in TLR7 and TLR8 genes might impair immune responses during HCV infection.

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Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v) reappeared in Taiwan in 1990 and 1994, following the first two epidemics of 1985--86 and 1988--89. To analyze the genetic diversity of recent CA24v in Taiwan, 7 Taiwanese strains isolated during the 1990--94 period were studied together with one Japanese and two Thai strains isolated in 1993. A fragment of 674 nucleotides between the carboxy terminal 3A and the amino terminal 3D polymerase, including the entire 3C protease (3C(pro)), was amplified by a reverse transcription-polymerase chain reaction (RT-PCR) and the nucleotide sequences were determined. In the 549 nucleotides (183 amino acids) of the entire 3C(pro), we found nucleotide differences at 80 positions between 10 strains and the prototype strain, EH24/70, one of the earliest strains of CA24v. Most of the nucleotide changes were synonymous substitutions and only nine amino acid changes were found. The nucleotide sequence homologies among 71 strains worldwide were 88-100%. These 71 nucleotide sequences were then analyzed by Neighbor-joining method and phylogenetically separated into three distinct genotypes. Genotype I consisted of early strains isolated in 1970--71 from Singapore and Hong Kong. Genotype II included isolates from Singapore and Thailand obtained in 1975. Genotype III comprised strains from the eastern hemisphere isolated in 1985--94 from Japan, Taiwan, China, Hong Kong, Thailand, Singapore, Pakistan and Ghana. They were further divided chronologically into six clusters. The recent isolates from Taiwan obtained in 1985/1986, 1988/1989 and 1990--94 were classified into genotype III Clusters 1, 5, and 6 respectively. The evolutionary rate was re-estimated to be 3 x 10(- 3) 30 years after the emergence of the virus.

Intracameral injection (ICI) of antibiotics and steroid is an effective method to deliver drugs into eyeballs, and rapidly achieve therapeutic concentrations. The high intraocular concentrations, however, that occur by such injections can harm the corneal endothelium. The MTT assay, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], has been used to test cytotoxicity of five antibiotics (including amphotericin-B, colistin-M, sulbenicillin, amikacin, cephradine) and a steroid, betamethasone, to cultured porcine corneal endothelial cells. The third passage of porcine corneal endothelial cells were plated into 96-well microtitration plates for drugs exposure. Cytotoxicities of the six drugs in different concentrations were compared, using exposure time as an independent variable. In its original and 10-fold ICI dose, only amphotericin-B among the six tested drugs showed significant cytotoxicity; the other drugs were considered safe. In a 100-fold ICI dose, amphotericin-B, colistin-M, and sulbenicillin were all toxic. Although a cell culture system utilizing the MTT assay is an in vitro method of testing for drug toxicity to the corneal endothelium, it nevertheless offers the advantages over in vivo methods. It is rapid, convenient, and economical. Large numbers of toxic compounds can be compared simultaneously, so that relative toxicities among different drugs and concentrations can be obtained, and be a guide for determining ICI dose, or as a reference for further in vivo testing.

Little is known about any consequences of swallowing tobacco-free betel-quid (TF-BQ) juice/remnants following chewing and its carcinogenic impact on the upper aerodigestive tract (UADT) to gastrointestinal tract (GIT). We investigated the neoplastic impact of TF-BQ on different anatomical locations along UADT and GIT, and differences according to their histological categories. We conducted a multicenter case-control study examining patients with 2,163 pathology-proven UADT and GIT cancers, comparing them with 2,250 control subjects. Generalized additive models, piecewise regression and polytomous logistic models were applied to identify possible dose-dependent structures and cancer risks. Contrary to nonsignificant GIT-adenocarcinoma risk (aOR 5 0.9), TF-BQ users experienced a 1.7-to 16.2-fold higher risk of UADT-squamous cell carcinomas than nonusers, with the peak risk discovered in oral neoplasms. We separately observed a curvilinear and linear TF-BQ dose-risk relationship in oral/pharyngeal/esophageal and laryngeal cancers. Chewers of betel inflorescence were generally at a greater UADT cancer risk. A higher first-piecewise increased risk of esophageal cancer was recognized among areca-fluid swallowers than among nonswallowers (continuous aOR 5 1.12 vs. 1.03). TF-BQ use accounted for 66.1-78.7% and 17.8-33.2% of the cases of oral/pharyngeal and esophageal/laryngeal cancers, respectively. However, a reduction from heavy TF-BQ consumption to low-to-moderate consumption only reduced 11.3-34.6% of etiologic fraction of oral/pharyngeal cancers. Alcohol supra-additively modified the risk of TF-BQ in determining the development of oral, pharyngeal and esophageal cancers. In conclusion, the interplay of TF-BQ and alcohol/tobacco use, combined with how chewing habit is practiced, influences carcinogenic consequences on anatomically diverse sites of UADT and GIT cancers, and histologically different types.