Serological approaches to distinguish immune response to hepatitis A vaccine and natural infection

Currently, the immune status of an individual exposed to hepatitis A virus (HAV) is determined by assays which measure antibodies against the capsid proteins. These assays indicate exposure to the viral capsid that could result from either infection or from vaccination. Recent data indicate that proteins from the non-structural genome region of the virus (P2 or P3), which are only produced during active virus replication, generate antibodies after clinical disease. A sub-genomic cDNA segment of HAV corresponding to the P2 region was used for in vitro transcription-translation followed by immune precipitation of the translated products under non-denaturing conditions. Serial serum specimens from experimentally infected chimpanzees and humans naturally infected with hepatitis A verified the development of antibodies to P2 proteins following infection. A serosurvey of individuals positive for antibodies to the HAV capsid (HAV AB assay, Abbott Laboratories) revealed that 50-60% of children and 16-32% of adults had no detectable antibodies to the P2 antigen by immune precipitation. These results may reflect subclinical infections resulting in a lower level of antibodies against the non-structural antigens or may represent a greater sensitivity of the competitive assay (HAV AB) used to detect capsid antibodies compared to the immunoprecipitation assay used to detect non-structural antigens.

Physical and molecular genetic analysis of Qa-2 antigen expression: multiple factors controlling cell surface levels

We have examined the surface expression of Qa-2 on lymphocyte subpopulations and on splenocytes from inbred mouse strains by a radioactive binding assay using purified anti-Qa-2 antibodies and antibody fragments (Fab). Quantitative measurements by Scatchard analysis revealed that spleen cells from Qa-2high mice express (4-5) x 10(4) Qa-2 molecules/cell, whereas T lymphocytes have as high as (7-8) x 10(4) molecules/cell. In addition, it was determined that B lymphocytes express (5-6) x 10(3) molecules on their cell surface. The Qa-2 levels on anti-CD3-activated T cells is 1.0 x 10(5) molecules/cell. Previous experiments have shown that the quantity of Qa-2 varies in a strain-specific fashion and may be classified into three groups: Qa-2high, Qa-2medium and Qa-2low. Our results indicated that Qa-2high strains express (4-5) x 10(4) Qa-2 molecules/cell, Qa-2medium strains (B6-K2, B10.A, A/J, BALB/c and DBA/2) express (1-1.7) x 10(4) molecules/cell, and Qa-2low strains (SWR/J and DBA/1) express no more than 6 x 10(3) molecules/cell. Detection of Q7 or Q9 mRNA by the polymerase chain reaction revealed that Qa-2high strains express two functional Qa-2 enconding genes, Q7 and Q9, whereas Qa-2medium and Qa-2low strains express either Q7 or Q9. These results strongly suggest that Qa-2 gene dosage contributes in part to the variation of Qa-2 levels on the cell surface.

[Quantitative analysis of calcium bilirubin in calculus bovis by infrared spectrometry]

This paper reports the method of quantitative analysis of calcium bilirubin in calculus bovis by infrared spectrometry. This method is simple and quick, requiring no separation and only small amount of sample, not destroying the sample and having few interferences.

[Malondialdehyde-modified-low density lipoprotein in diabetes mellitus]

Malondialdehyde-modified-low density lipoprotein (MDA-LDL), lipid peroxide (LPO), lipid and fasting blood glucose (FBG) were studied in 42 diabetic patients and 20 age-matched controls. The results revealed that both MDA-LDL per L serum and MDA-LDL per mol LDL-C of diabetics were higher than those of controls. MDA-LDL/L tended to be much higher in diabetic patients with vascular disease and hyperlipidemia. There was a positive correlation between MDA-LDL/L and LPO, LDL-C, TC, respectively.

[Glycosylated hemoglobin in the diagnosis of diabetes mellitus]

Blood glucose at fasting and 1, 2, and 3 hours after meals GHb (glycosylated hemoglobin) were determined in 66 subjects. Based on WHO criterion, 34 of them were diabetics, and 32 were nondiabetics, in whom impairing of glucose tolerance (IGT) and diabetes were ruled out. The results showed that the concentrations of blood glucose, at fasting, and 1, 2, and 3 hours after meals, blood glucose area, and GHb in diabetic patients were significantly higher than those in the controls. There was a significant positive correlation between GHb and blood glucose at fasting and 2 hours after meal, and between GHb and blood glucose area in all subjects. Relative sensitivity of GHb for detecting diabetes mellitus was 88%, and relative specificity was 93.75%.

[Relation of Fourier transform infrared spectroscopic characteristics of pilose antler and its traditional quality grade]

The relationship between FTIR characteristics of Pilose Antler and its traditional quality grade was studied and a rule governing its quality value "Z" was found. We have thus advanced a new objective target for preparing Pilose Antler tablets and powder.

[Studies on calculus bovis by FTIR-PAS]

This article reports the characteristics of different colour layers of Calculus Bovis by FTIR-PAS. It is unnecessary to treat the sample before analysis, and the sample can be reused after analysis. The method is fast accurate and easy to operate.