A case series of dengue fever with altered consciousness and electroencephalogram changes in Sri Lanka

We describe six serology-positive dengue patients presenting sporadically over 8 years, who lapsed into coma and showed generalized irregular slow waves in consecutive electroencephalograms (EEG) in the absence of any structural brain damage. The mean age was 41 years (range 16-65). All had fever, headache and vomiting for 3 days (range 2-4) on admission and developed coma after 24 h. Five patients developed generalized convulsions and two showed generalized paroxysmal spike-wave discharges in the EEG. All regained normal consciousness within 36 h. In two patients, slow waves in the EEG persisted for 6 and 18 months.

A novel reverse transcriptase-polymerase chain reaction based-liquid hybridisation (RT-PCR-LH) assay for early diagnosis of dengue infection

BACKGROUND

Early definitive laboratory diagnosis of dengue is difficult with the tests in routine use at present.

OBJECTIVE

To develop a reverse transcriptase-polymerase chain reaction based liquid hybridisation (RT-PCR-LH) technique for the rapid and early diagnosis of dengue.

RESEARCH DESIGN

RT-PCR products of the NS3 gene of dengue virus prototypes and of a few positive sera for dengue virus by culture, were allowed to hybridise in liquid phase with a mixture of dengue specific radiolabelled oligonucleotides. The products were separated by PAGE and visualised by autoradiography. 78 suspected dengue sera were also tested by RT-PCR-LH method, and by IgM-ELISA and HAI tests, for comparison.

RESULTS

Two DNA bands (approximately equal to 470 bp and approximately equal to 455 bp) specific to dengue virus, were observed. RT-PCR-LH assay takes only 24 h. Of the 78 suspected dengue acute sera tested, 45/78 were positive by RT-PCR-LH, 31/78 were positive by IgM-ELISA, and 14/78 had a HAI titre > or = 2560. Duration of fever was known in 72 cases, and infection was detected by RT-PCR-LH in 11/22 of cases with < 5 d fever and by IgM-ELISA in 1/22. In cases with 5 to 15 d fever RT-PCR-LH and IgM-ELISA/HAI titre > or = 2560 detected infection in 30/50 and 27/50 respectively. The 10 sera which were negative by RT-PCR-LH, but were positive by either IgM-ELISA or HAI titre > or = 2560 were all > 5 d fever cases. RT-PCR-LH together with IgM-ELISA were capable of detecting dengue infection in 56/78 of the suspected cases.

CONCLUSION

RT-PCR-LH assay developed in this study appears to have an advantage over other diagnostic techniques for the early detection of dengue.

Expression of cathepsins B, L, S, and D by gastric epithelial cells implicates them as antigen presenting cells in local immune responses

Helicobacter pylori infection is linked to chronic gastritis, peptic ulcer and gastric carcinoma. During H. pylori infection, class II MHC expression by the gastric epithelium increases, as does the number of local CD4(+) T cells, which appear to be important in the associated pathogenesis. These observations suggested that the epithelium might present antigens to T cells. Thus, we sought to determine whether gastric epithelial cells process antigens to establish their function as local antigen presenting cells (APC). We examined a panel of gastric epithelial cell lines for expression of the antigen processing cathepsins B (CB), L (CL), S (CS), and D (CD). The mRNA for these enzymes were detected by RT-PCR and the enzymes in the gastric epithelial cells were identified by various independent methods. We corroborated the expression of CB and CD on gastric epithelial cells from human biopsy samples. The functions of these proteases were confirmed by assessing their ability to digest ovalbumin, a conventional dietary antigen, and proteins from H. pylori. In summary, multiple lines of evidence suggest gastric epithelial cells process antigens for presentation to CD4(+) T cells. To our knowledge, these are the first studies to document the antigen processing capacity of human gastric epithelial cells.

Relative frequency of VP4 gene alleles among human rotaviruses recovered over a 10-year period (1982-1991) from Japanese children with diarrhea

The relative frequencies of the Wa (corresponding to serotype P1A), DS-1(P1B), M37(P2), and AU-1(P3) alleles of the VP4 gene from rotaviruses collected from the stools of individuals in Japan between 1982 and 1991 were determined to be 83.1, 15.6, 0, and 1.3%, respectively, by a polymerase chain reaction-based typing assay.