Cloning and comparison of ten gene sequences of a Chilean H. pylori strain with other H. pylori strains revealed higher variability for VacA and CagA virulence factors.

We have cloned and sequenced ten Helicobacter pylori genes from a Chilean strain (CH-CTX1) including: a cytotoxin VacA fragment, a CagA fragment (A17), a species-specific protein (TsaA), urease subunits (UreA, UreB), a flagellin subunit (FlaB), heat shock proteins (HspA and HspB), adhesin (HpaA) and a lipoprotein (Lpp20). We compared their deduced amino acid sequences with the corresponding sequences from three unrelated H. pylori strains, including fully sequenced strains 26695(UK) and J99(USA), and found that eight of them (UreA, UreB, FlaB, HspA, HspB, Lpp20, TsaA and HpaA) presented more than 97.

Serological response to Helicobacter pylori recombinant antigens in Chilean infected patients with duodenal ulcer, non-ulcer dyspepsia and gastric cancer.

We have previously cloned 10 Helicobacter pylori antigen genes from a Chilean strain including: cytotoxin VacA, a truncated region of CagA (called A17), a species-specific protein (Ag26), urease subunits (UreA, UreB), a flagellin, (FlaB), heat shock proteins (HspA and HspB), an adhesin (HpaA) and a lipoprotein (Lpp20). Immunogenicity of these antigens was tested by immunoblot with sera of Chilean infected patients, revealing that HpaA, A17, HspB and VacA were more frequently recognized (86%, 82%, 68% and 68%, respectively). According to the clinical condition, it was determined that Lpp20 was preferentially recognized by sera from non-ulcer dyspepsia patients (80%), A17 and VacA by patients with duodenal ulcer (92% and 83% respectively), and HspB by patients with duodenal ulcer (83%) and gastric cancer (90%).

An alternative ELISA for T4 determination based on idiotype anti-idiotype interaction and a latex method for anti-idiotype monoclonal antibody selection.

This paper is the first report on the use of an idiotype-anti-idiotype monoclonal antibody reaction to develop an enzyme immunoassay for thyroxine (T4). We have developed a monoclonal antibody against T4, named 1F10 of IgG1 subclass and KA 5.21 x 10(8) M-1 which was used to obtain anti-idiotypic monoclonal antibodies.

Respiratory syncytial virus detection by dot blot hybridization with a nonradioactive synthetic oligo deoxynucleotide probe.

A synthetic oligodeoxynucleotide corresponding to a region of the nucleocapside gene (N) of respiratory syncytial virus (RSV), was used as a DNA probe to develop a nonradioactive hybridization assay for the detection of RSV. The probe was labeled by incorporation of biotin-7-dATP to the 3' end by a reaction catalyzed by terminal deoxynucleotydil transferase. The dot blot hybridization assay was found to be specific for RSV when tested against RSV isolates (subgroups A and B) obtained from cell cultures and isolates of adenovirus, reovirus, rotavirus, and pararotavirus.

Rotavirus detection by dot blot hybridization assay using a non-radioactive synthetic oligodeoxynucleotide probe.

A synthetic oligodeoxynucleotide of 40 nucleotides corresponding to nucleotides 33-72 of the gene coding for the viral protein VP7 of rotavirus, was used as a nucleic acid probe to develop a non-radioactive hybridization method for rotavirus detection. The probe was labelled at the 3' end with biotin-7-dATP. The sensitivity and specificity of the dot blot hybridization assay for rotavirus detection was evaluated with 303 stool specimens.