Seroprevalence of cytomegalovirus infection in Mauritian volunteer blood donors.

OBJECTIVE: To determine the seroprevalence of CMV antibodies in the Mauritian volunteer blood donor population and to establish a panel of CMV-seronegative blood donors. STUDY SUBJECTS AND METHODS: Five hundred and eighty four apparently healthy blood donors were screened for evidence of CMV infection by the complement fixation test. There were 551 males and 33 females with age ranging from 18 to 60 years. RESULTS: Complement-fixing antibodies were found in 93.5% of the blood donors. The prevalence was 93.1% in males and 100% in females. CONCLUSION: Our findings demonstrate that seroprevalence of CMV in the local blood donors is very high making CMV-seronegative blood very scarce. Therefore leucocyte-depleted blood should be used as an alternative to CMV-seronegative blood during transfusions.

Mutation analysis of a Mauritian hereditary breast cancer family reveals the BRCA2 6503deITT mutation previously found to recur in different ethnic populations.

Mauritius, a small island some 855 km off the east coast of Madagascar, has a multiethnic population of about 1.2 million with a high population density of about 611 per km(2). The recent industrialization of the island seems to have been accompanied, in less than 10 years, by an increase of at least 30% in breast cancer incidence. We have detected the BRCA2 6503delTT mutation in two sisters of the same family of Indian origin but living in Mauritius for at least five generations. This mutation has been found to recur in geographically diverse populations and haplotype analysis has shown a common ancestry. The haplotype of the mutation found in the Mauritian family differs from that found in other populations harbouring the same mutation, suggesting that the BRCA2 6503delTT mutation most likely arose independently.

Detection of cytomegalovirus in urine of hearing-impaired and mentally retarded children by PCR and cell culture.

This study was carried out to determine the prevalence of cytomegalovirus (CMV) excretion in urine among 30 deaf children and 91 mentally retarded children by cell culture and PCR. As a control, urine samples from 121 children without hearing disability or mental retardation were also tested. The study revealed that 15 of 30 (50%) deaf children and 16 of 91 (17.6%) mentally retarded children were excreting CMV in their urine. Among the control group we observed that only 2 of the 121 (1.8%) children were CMV excretors. As CMV excretion in urine is generally considered to indicate a congenital infection, it is very likely that congenital CMV is highly incriminated in mental retardation and deafness among children in Mauritius.

Isolation of a major form of pepsinogen from gastric mucosa of horses.

In mammalian species studied previously, pepsinogen consisted of biochemically different groups of isozymogens. By use of gel filtration chromatography and electrophoresis, we isolated a predominant pepsinogen from the gastric mucosa of a horse. Peptide mapping with V8 protease revealed differences with its porcine homologue. However, porcine and equine pepsinogens, when activated to pepsin, had a similar pattern of activity when hemoglobin was used as substrate. Those results suggest that differences must exist in the primary structure of the pepsinogens of the 2 species.

Role of the nuclear matrix in adenovirus maturation.

The nuclear matrix has been implicated in several important cellular processes. In this paper, we investigate the role of the nuclear matrix in adenovirus type 2 assembly. Electron microscopic examination of nuclear matrices isolated from adenovirus infected Hep-2 cells clearly reveals that late in the lytic cycle, adenovirus capsids are intimately associated with the nuclear matrix. SDS-PAGE analysis showed that the viral core polypeptides V, PVII and 11 kDa were enriched in the nuclear matrix fraction. After a 3 h chase period a constant high ratio of PVII to VII prevailed in the nuclear matrix suggesting that mostly young virions and viral cores are bound to this structure. Most of the virus maturation endoproteinase activity co-purified with the nuclear matrix and the data suggest that the enzyme may be released from fragile young virions or assembly intermediates. Together these experiments suggest that the nuclear matrix is the site of adenovirus assembly and that mature virions may be released from the matrix by the viral endoproteinase.

The role of phosphorylation and core protein V in adenovirus assembly.

The role of phosphorylation and the minor core protein V in adenovirus type 2 assembly was examined. Comparison of the phosphoprotein composition of top components (TC), young virions and mature virions of wild-type and assembly mutants showed specific changes related to virus assembly and maturation. TC were identified as precursors of young virions which contain two molecular weight forms of core protein V, one of which is phosphorylated. Conversion of TC into young virions by DNA encapsidation resulted in the loss of the unphosphorylated form of protein V, and subsequent maturation to old virions resulted in the dephosphorylation of the core protein. This last step is blocked by the tsl mutation which inactivates the viral endoproteinase.

The nature of the DNA associated with incomplete particles of adenovirus type 2.

The nature of the DNA in incomplete particles (IP) synthesized by adenovirus type 2 and the ts4 mutant which accumulates such particles were analysed by agarose gel electrophoresis, restriction endonuclease cleavage and blot hybridization techniques. IP DNA consisted of a heterogeneous population of subgenomic-size DNA (IPSD1) and smaller molecules ranging from about 1000 base pairs to 200 base pairs (IPSD2). IPSD1 from ts4 was more heterogeneous than that from wild-type (wt), but both contained sequences from all parts of the viral genome. IPSD2 contained heterogeneous cellular sequences and viral sequences from the left 4.4% of the genome. An endonuclease activity associated with IP and virions was capable of digesting viral or cellular DNA to IPSD2-like fragments suggesting a possible origin for these molecules.

Genetic Analysis of Adenovirus Type 2 II. Preliminary Phenotypic Characterization of Temperature-Sensitive Mutants.

The properties of temperature-sensitive mutants of adenovirus type 2 representing 12 complementation groups were studied. All mutants were normal with respect to adsorption as measured by viral inclusion formation and viral DNA synthesis as shown by velocity sedimentation in alkaline sucrose gradients. One mutant, however, formed viral inclusions of altered morphology at the nonpermissive temperature. The synthesis of the major capsid proteins was examined by immunodiffusion. On this basis, the complementation groups could be arranged as follows: (i) one group was negative for all three proteins; (ii) three groups failed to synthesize penton bases; (iii) eight groups were positive for hexons, pentons, and fibers. The assembly of virus particles at 39 C was examined by equilibrium sedimentation in CsCl; three groups were found defective, whereas two of the penton-negative groups were positive for virion production. Tests of the thermolability of virions at 50 C revealed eight groups labile whereas the remainder were insensitive to heat inactivation. None of five mutants inoculated in newborn rats induced tumors, although three of them were capable of in vitro transformation.