Elucidation of the full genetic information of Japanese rubella vaccines and the genetic changes associated with in vitro and in vivo vaccine virus phenotypes.

Rubella is a mild disease characterized by low-grade fever, and a morbilliform rash, but causes congenital defects in neonates born from mothers who suffered from rubella during the pregnancy. After many passages of wild-type rubella virus strains in various types of cultured cells, five live attenuated rubella vaccines were developed in Japan. An inability to elicit anti-rubella virus antibodies in experimentally infected animals was used as an in vivo marker phenotype of Japanese rubella vaccines. All Japanese rubella vaccine viruses exhibit a temperature-sensitive (ts) phenotype, and replicate very poorly at a high temperature. We determined the entire genome sequences of three Japanese rubella vaccines (Matsuba, TCRB19, and Matsuura), thereby completing the sequencing of all five Japanese rubella vaccines. In addition, the entire genome sequences of three vaccine progenitors were determined. Comparative nucleotide sequence analyses revealed mutations that were introduced into the genomes of the TO-336 and Matsuura vaccines during their production by laboratory passaging. Analyses involving cellular expression of viral P150 nonstructural protein-derived peptides revealed that the N1159S mutation conferred the ts phenotype on the TO-336 vaccine, and that reduced thermal stability of the P150 protease domain was a cause of the ts phenotype of some rubella vaccine viruses. The ts phenotype of vaccine viruses was not necessarily correlated with their inability to elicit humoral immune responses in animals. Therefore, the molecular mechanisms underlying the inability of these vaccines to elicit humoral responses in animals are more complicated than the previously considered mechanism involving the ts phenotype as the major cause.

[The present situation and limitation of antibody assays for diagnosis of rubella virus infection in pregnant women].

Rubella virus infection during early stages of pregnancy often results in a number of developmental disorders referred to as congenital rubella syndrome(CRS). Both clinical and laboratory diagnosis of suspect cases of CRS can be made with relative ease, particularly when expectant mothers show the typical rubella-specific rash. Serological diagnosis of CRS is accomplished using hemagglutination inhibition (HI) and enzyme-linked immunosorbent(IgM-EIA) assays. Antibody titers as determined by these assays are generally very high following acute apparent rubella infections, thus making serological diagnosis relatively easy in most cases. However, the detection of possible CRS cases can be hampered by clinically inapparent rubella infections during early pregnancy. As much as 30 percent of all acute rubella cases are inapparent infections, and there is the very real potential for such inapparent infections to occur during pregnancy, to result in fetal infections, and consequently to cause CRS. Detection of CRS becomes extremely difficult in such settings. Complicating CRS detection even more are rare rubella re-infections that might occur in early pregnancy, and unknown risk of fetal infection and CRS. In re-infection cases, HI antibody titer becomes elevated due to a secondary immune response, and IgM antibody is produced in a significant number of cases. To determine directly the fetal infection, virus genome detection was developed and applied clinically for the past decade. Using a combination of serological and genomic detection methods, the results of the investigation suggest that when rubella infection during early pregnancy occurs 1) there is a significant risk of fetal infection that results from acute apparent rubella infection, 2) there is a measurable risk of fetal infection resulting from inapparent infections as defined by HI antibody titers > or = 256 and with and IgM-EIA index > or = 7, and 3) high HI antibody titers with low IgM-EIA indices or no detectable IgM antibody in cases of inapparent rubella infections may represent rubella re-infections and result in a low risk of fetal infections.

[Estimated production by the official inspection of tar colors (including aluminum lakes) in fiscal year 2001].

There were 162 official inspections of tar colors and their lakes in fiscal year 2001, and 162 samples were qualified. Total production amount of tar colors that passed inspection in Japan in fiscal year 2001 reached 134.8 tons. Tar color production amounts were described by month and by manufacturer. The food tar color produced in the largest amount was Food Yellow No. 4, accounting for 43.9% during this period. Their yearly total productions were decreased from 238.7 to 134.8 tons during 12 years.

[Determination and survey of hexachlorobenzene in food red nos. 104 (phloxine) and 105 (rose bengale) by GC/MS].

The contents of hexachlorobenzene (HCB) in Food Red Nos. 104 and 105 samples certified in fiscal years 1998-2001 were determined by GC/MS. All 32 samples contained HCB ranging from 0.2 to 32.9 mg/kg. The daily intakes of HCB based on the production of food colors was estimated to be from 0.018 to 1.456 ng, and their average (0.441 ng) corresponded to 0.0052% of the ratio for the Tolerable Daily Intake (8.5 micrograms for 50 kg body weight) of HCB developed by the IPCS.