Evaluation of different adjuvants for foot-and-mouth disease vaccine containing all the SAT serotypes.

Foot-and-mouth disease (FMD) is an economically important disease of cloven-hoofed animals that is primarily controlled by vaccination of susceptible animals and movement restrictions for animals and animal-derived products in South Africa. Vaccination using aluminium hydroxide gel-saponin (AS) adjuvanted vaccines containing the South African Territories (SAT) serotypes has been shown to be effective both in ensuring that disease does not spread from the endemic to the free zone and in controlling outbreaks in the free zone. Various vaccine formulations containing antigens derived from the SAT serotypes were tested in cattle that were challenged 1 year later. Both the AS and ISA 206B vaccines adjuvanted with saponin protected cattle against virulent virus challenge. The oil-based ISA 206B-adjuvanted vaccine with and without stimulators was evaluated in a field trial and both elicited antibody responses that lasted for 1 year. Furthermore, the ISA 206 adjuvanted FMD vaccine protected groups of cattle against homologous virus challenge at very low payloads, while pigs vaccinated with an emergency ISA 206B-based FMD vaccine containing the SAT 1 vaccine strains were protected against the heterologous SAT 1 outbreak strain.

New developments in the Peterson olefination reaction.

Noteworthy developments of the Peterson olefination reaction are reviewed. Evidence for both concerted and stepwise mechanisms for the Peterson olefination reaction is presented. The strong affinity of the oxygen anion for the silyl moiety is emphasised when the Peterson olefination reaction takes preference over both the Julia and Wittig reactions in the presence of S- and P-stabilised silyl carbanions. Cerium-mediated Peterson methylenation reactions are discussed.

A unique segment of the hepatitis B virus group A genotype identified in isolates from South Africa.

The preS2/S genes of hepatitis B virus isolated from 29 acutely or chronically infected individuals in the Gauteng province of South Africa were sequenced. Phylogenetic analysis of these sequences in comparison with global isolates from the GenBank database showed that 24 sequences clustered with genotypic group A, three with genotypic group D and one each with genotypic groups B and C. Group A isolates had greater identity with groups D (variation of 6.6%) and E (6.8%) than with the Eastern groups B (7.4%) and C (8.1%) and were most different from group F (11.0%). Of the South African group A specimens, 59.1% clustered with two global sequences to form a discrete segment which we have called subgroup A. The amino acid differences that set these isolates apart from the rest of group A tended to cluster in the preS2 region (amino acids 7, 10, 32, 35, 47, 48, 53 and 54), with a few changes occurring in the major surface antigen (amino acid sites 207 and 209). Analysis of isolates showed that there was a 9-fold higher prevalence of the ay determinant in South Africa than previously reported.

Serum alpha-fetoprotein concentrations in urban and rural Southern African blacks with hepatocellular carcinoma.

The reason why only some hepatocellular carcinomas synthesize alpha-fetoprotein is not known. Both the frequency with which this foetal globulin is produced and the major aetiological associations of hepatocellular carcinoma vary between populations with high and low incidences of the tumour, raising the possibility that re-expression of the gene for alpha-fetoprotein is determined, or influenced by, the molecular genetic events that occur during hepatocellular carcinogenesis. This hypothesis could be tested by comparing serum alpha-fetoprotein concentrations in populations in which the major risk factors for hepatocellular carcinoma differ. Two such populations are urban and rural southern African blacks. We measured serum alpha-fetoprotein concentrations by radioimmunoassay in 234 southern African blacks with hepatocellular carcinoma: 78 of the patients were urban and they were age-matched with 156 patients born in rural areas, one-half of whom had remained in a rural environment (rural), whereas the others had migrated to the cities in adulthood (rural-urban). Urban patients were more likely than rural-born patients to have a normal serum alpha-fetoprotein value [23.1% (18/78) compared with 10.2% (16/156); p = 0.02]. There was no significant difference between the concentrations in rural and rural-urban patients. The absolute values of the raised serum alpha-fetoprotein values did not differ between urban (69,558 +/- 176,737 ng/ml; and rural-born patients (53,998 +/- 125,681 ng/ml), or between rural (69,207 +/- 159,975 ng/ml) and urban-rural patients (40,434 +/- 83,028 ng/ml). These findings are compatible with the hypothesis that re-expression of the alpha-fetoprotein gene in hepatocellular carcinoma is related to the aetiology or pathogenesis of the tumour.

Differential lectin reactivities of alpha-fetoprotein in hepatocellular carcinoma: diagnostic value when serum alpha-fetoprotein levels are slightly raised.

The specificity and sensitivity of alpha-fetoprotein (AFP) binding to Concanavalin-A (Con-A) and Lens culinaris agglutinin (LCA) in 26 South African blacks with advanced symptomatic hepatocellular carcinoma (HCC) but only slightly raised serum AFP concentrations (20-500 ng/mL) was compared with that in patients with similar serum AFP levels from diseases that might be mistaken clinically for HCC (seven 'benign' liver disease [BLD] patients and six with metastatic liver disease [MLD] from gastrointestinal tumours). Con-A-Sepharose-4B affinity chromatography did not differentiate between the different groups: fucosylation rations for the HCC patients were 0.81 +/- 0.60, compared with 0.63 +/- 0.27 and 0.54 +/- 0.32 in patients with BLD and MLD, respectively. Electrophoresis of AFP serum and fraction in the presence or absence of Con-A and LCA showed an increase in the AFP C2 band. Rank correlation analysis of the AFP L2 and L3 bands combined could distinguish between patients with HCC and other hepatic diseases (P less than 0.05).

The pathogenesis of raised serum alpha-fetoprotein levels in amoebic and pyogenic hepatic abscesses.

Serum alpha-fetoprotein (AFP) concentrations may be slightly raised in patients with amoebic hepatic abscesses. In an attempt to learn more about the pathogenesis of the raised levels, we studied 74 patients with amoebic and six with pyogenic hepatic abscesses. Serum (AFP) levels were slightly elevated (24-72 ng/ml) on admission in four patients and markedly raised (2000 ng/ml) in one, who had hepatocellular carcinoma in addition to a pyogenic hepatic abscess. The pattern of the early rise in AFP levels could not be determined because these four patients were lost to follow-up. However, serial serum AFP estimations were obtained in 29 patients with a normal value on admission and in none of these did the concentration rise during recovery. Our findings do not support the prevailing hypothesis that regenerating hepatocytes are responsible for the raised serum AFP levels in non-neoplastic hepatic disorders, including hepatic abscesses.