Smears from rat liver suspension as modified substrate for antinuclear antibody test.

Immunofluorescence still remains a standard method for documenting antinuclear antibodies (ANA). Cryostat cut sections of rodent liver or Hep2 cell nuclei have been used as substrate in the test but are often difficult to arrange in laboratories in developing countries. Hence, a modification was developed using smears from rat liver suspensions. The smears were compared with the cryostat cut sections over 338 sera samples of suspected cases of collagen diseases, rheumatoid arthritis, thyroid disorders, hepatitis B, enteric fever, tuberculosis and normal subjects. The sera from suspected collagen diseases cases were also compared with ANA test using Hep2 cells. The modified smear technique was well comparable and the clarity of the immunofluorescence was even better than for cryostat cut sections. Using the modified smear technique 272 sera out of 2,851 sera gave positive test for ANA. The homogenous, speckled and peripheral patterns were seen for 203, 66 and 3 samples respectively. To conclude: The smears prepared from homogenised rat liver suspension and fixed like bacterial smears offer a very convenient and reliable tissue substrate for ANA test.

Immunogenicity of low dose hepatitis B vaccine by the intradermal route & persistence of anti-HBs after three years.

Plasma derived hepatitis B vaccine given intradermally (0.2 ml; 4 micrograms HBsAg) at 0, 1, 6 months to 200 health care workers, produced seroconversion in 97.5 per cent. Antibody levels to hepatitis B surface antigen (anti-HBs) crossed 1000 mIU/ml in 62 per cent while 26.5 per cent had levels of 100 to 1000 mIU/ml. Anti-HBs levels persisted in the same range in 41.7 per cent but dropped by a log in 58.3 per cent subjects at the end of 3 yr. Protective antibodies above 10 mIU/ml were documented in 93.3 per cent vaccinees after 3 yr. The 0.2 ml vaccine by intradermal (id) route was also found to give a good booster effect in another group of 27 persons who had received full dose vaccine 5 yr earlier. Thus, 0.2 ml vaccine by id route was safe, gave high seroconversion and persistent antibody levels over 3 yr and could offer effective protection at an economic cost.

Amino acids: modifiers of xanthine oxidase activity.

L-Glutamic acid has been found to be a positive and L-lysine a negative modifier of the xanthine oxidase activity at the optimum pH (7.4) of the enzyme. Increase in pH was observed to be associated with a progressive decrease in the inhibition produced by L-lysine.