Quantitative Analysis of Viral RNA in the Murine Heart and Pancreas with Different Concentration of Coxsackievirus B3

OBJECTIVES

We investigated the clinical features, pathologic changes, and viral RNA kinetics in the course of acute and subacute experimental coxsackievirus B3 (CVB3) infection in a murine model.

METHODS

Five-week-old A/J inbred male mice were divided into 5 groups. Four of those groups were inoculated intraperitoneally with 5 x 10(4) (group 1), 1 x 10(5) (group 2), 5 x 10(5) (group 3), or 1 x 10(6) (group 4) PFU of CVB3. Control mice were inoculated with uninfected Vero cell lysate in DMEM. Mice from each group were sacrificed on days 7 or 14 after inoculation.

RESULTS

Bloody diarrhea, earlier weight loss, perianal swelling, and death were correlated with higher viral load. One of ten mice in group 3 and 5 of 10 mice in group 4 died spontaneously between days 4 and 12 after inoculation. All of the remaining 34 mice of infected groups demonstrated extensive pancreatic inflammation. Focal myocarditis developed in only 4 (11.8%) of those 34 subjects. Amylase and creatine kinase activities in the serum were increased in the mice of infected groups. CVB3 RNA was detected in the heart and pancreatic tissue in all subjects. The CVB3 RNA copy number in pancreatic tissue was not correlated with the severity of inflammation.

CONCLUSIONS

In the murine model, viral loading dose determines the clinical features of CVB3-induced infection, and the severity of pancreatitis is not correlated with the viral loading dose or tissue level of viral RNA. .

Effect of water-soluble reduced chitosan on Streptococcus mutans, plaque regrowth and biofilm vitality

The purpose of the present study was to examine the effects of a newly developed water-soluble reduced chitosan on Streptococcus mutans, plaque regrowth, and biofilm vitality. A 1.0%, water-soluble reduced chitosan, with pH ranging from 6.0 to 6.5, molecular weights between 3,000 and 5,000 Da, and 70% degree of deacetylation, was used. To determine antibacterial and antiplaque potency of chitosan, minimal inhibitory concentrations (MICs) for S. mutans and S. sanguinis (formerly S. sanguis), short-term exposure to S. mutans, and clinical trial of plaque regrowth and biofilm vitality were conducted. Twelve dental students volunteered to participate in the 6-week, double blind, randomized clinical trial using the classical 4-day plaque regrowth design. The MIC of water-soluble reduced chitosan for S. mutans was 1.25 g/l. While the cells exposed to distilled water (DW) grew rapidly, with a maximum turbidity reached by 16 h postinoculation, S. mutans exposed to chitosan (5.0 g/l) exhibited a substantial delay in growth and reached a maximum turbidity by 32 h postinoculation. The chitosan solution reduced the plaque index and the vitality of the plaque flora significantly when compared to DW, but this was less than the reductions found with the positive control of 0.1% chlorhexidine solution. The water-soluble reduced chitosan exhibited potent antibacterial effect on S. mutans, and displayed a significant antibacterial and plaque-reducing action during the 4-day plaque regrowth.

Distribution of Viral RNA in Mouse Tissues during Acute Phase of Coxsackievirus B5 Infection

OBJECTIVE

To investigate histopathological changes and distribution of coxsackievirus B5 (CVB5) RNA in mouse heart, liver, and pancreas during the acute phase of infection.

METHODS

C3H/HeJ male mice, aged 3-4 weeks, were inoculated intraperitoneally with 5 x 10(5) plaque-forming units of CVB5 and sacrificed at 1, 2, 3, 4, 7 and 10 days postinfection (p.i.). Inflammation of the heart, liver, and pancreatic tissue sections was evaluated by hematoxylin and eosin staining, and virus was detected using antibody to viral coat protein VP1. A quantitative real-time RT-PCR method, using primers and probe targeted to the highly conserved sequences in the 5'-untranslated region of the virus, was used to evaluate the kinetics of CVB5 RNA during the development of myocarditis or pancreatitis.

RESULTS

Marginal inflammatory changes were observed in the heart tissues although viral RNA was constantly present between 1 and 10 days p.i., peaking at 4 days p.i. The pancreatic tissues displayed massive lymphocyte infiltration and loss of acinar cells at day 4 p.i. and viral RNA was detected between 1 and 10 days p.i., peaking at 2-3 days p.i. In the liver, viral RNA was detected between 1 and 7 days. No mortality was observed.

CONCLUSIONS

CVB5 induced acute pancreatitis without subsequent development of myocarditis. Clearance of CVB5 RNA from the pancreas and heart was slower than clearance from the liver. Our real-time RT-PCR method, which is more sensitive than conventional plaque assay, may provide valuable insight into viral RNA kinetics during CVB5 infection.

Immunohistochemical characterization of macrophage and dendritic cell subpopulations of the spleen, thymus, tongue and heart in cyclophosphamide-induced immunosuppressed rat

This study was undertaken to investigate the immunohistochemical characterization of different subpopulations of macrophages and dendritic cells (DCs) of the spleen, thymus, tongue and heart in cyclophosphamide (CY)-induced immunosuppressed rat. After CY treatment, remarkably, ED1+, ED2+ and ED3+ macrophage subpopulations, in general exhibited signs of cellular activation such as an increase in number and size of cell, and an upregulation of the ED1, ED2 and ED3 reactive surface molecule expression in all the organs studied, except for some macrophage subpopulations including ED1+ macrophages in the non-lymphoid tissues. Subpopulations of DCs showed a differential sensitivity to CY. Lymphoid DCs were more sensitive to CY than non-lymphoid interstitial DCs. CY induced a conspicuous upregulation of intercellular adhesion molecule-1 (ICAM-1) expression in the vascular endothelial cells, splenic marginal zone and thymic cortex. In this study, we demonstrated the in vivo effects of CY treatment on subpopulations of macrophages and DCs as well as on ICAM-1 expression in the rat spleen, thymus, tongue and heart. Moreover, our results shed more light on the activation effects of CY on certain subpopulations of macrophages, on the differential sensitivity of DCs to CY between the immature and mature ones, on the functional role of different subpopulations of macrophages, and on the significance of upregulated ICAM-1 expression in the splenic marginal zone and thymic cortex after CY treatment.

[The clinical significance of quantitation of HBV DNA in serum-comparison of the branched-DNA assay with the second-generation digene hybrid capture assay and long-term observation]

BACKGROUND/AIMS

Serum levels of hepatitis B virus (HBV) DNA are direct measures of viral replication in hepatocytes. We compared branched-DNA assay (Quantiplex(TM), bDNA) and Hybridization Capture II (HCII), and evaluated the clinical significance of HBV DNA quantitation in the natural course of HBV infection.

METHODS

We analyzed results of bDNA in 324 serum samples from 83 untreated male patients with chronic hepatitis B. Mean follow up period was 11.8 years. HCII was also performed in 157 arbitrarily selected samples.

RESULTS

HBV DNA levels measured with two assays were very similar (r(2)=0.893, p<0.0001). HBV DNA detection rate of HCII was 6.4% higher than that of bDNA in HBeAg positive samples. HBV DNA detection rate was higher in cases with higher ALT. Among 73 patients with initial diagnosis of chronic hepatitis, 38 patients (52.1%) experienced progression to cirrhosis, and hepatocellular carcinoma (HCC) was developed in 9 (12.3%). HCC was developed in 5 (50.0%) of 10 patients with initial diagnosis of cirrhosis. While HBeAg positive rates during chronic hepatitis, cirrhosis and HCC were 57.8%, 55.0% and 14.3%, respectively (p=0.006), HBV DNA detection rates were 70.6%, 64.0% and 42.9%, respectively (p=0.08). Especially in HCC, the discrepancy between HBeAg positive rate and HBV DNA detection rate may suggest the appearance of variants which cannot produce HBeAg.

CONCLUSION

Both HCII and bDNA were similar HBV DNA quantitation assays for clinical use. HBV DNA level correlated with the severity of liver disease. Screening tests for HCC should be recommended in patients whose HBeAg is negative and have detectable HBV DNA.