Isolation and characterization of a monoclonal anti-P30 antibody resistant mutant of Toxoplasma gondii

Of the possible iodine-labelled Toxoplasma gondii surface proteins, P30 (apparent Mr 30,000) is the principal one recognized by acute and convalescent anti-toxoplasma sera. This protein which comprises from 3 to 5% of the total parasite protein was used to raise a panel of parasiticidal monoclonal anti-P30 antibodies. One of these monoclonal antibodies was able to select a resistant mutant from a large population of chemically mutagenized wild-type P strain parasites. This mutant retained the wild type sensitivity to other non-P30 parasiticidal monoclonal antibodies as well as polyclonal anti-P30 rabbit sera. Analysis of surface radioiodinated wild type and mutant parasites showed that the mutant had a quantitative reduction in the amount of P30. A comparison of surface biotin labelled wild type and resistant parasites by two dimensional electrophoresis showed that the mutant lacked one and possibly two of several proteins that make up wild type P30. Western blot analysis indicated that the mutant was devoid of antigenically reactive P30. These findings further support the hypothesis that antigenic variants of T. gondii can be induced and may involve the major surface membrane antigens of the parasite.     

Detection of traumatic myocardial injury by means of simultaneous T1-201/Tc-99m pyrophosphate tomography--report of three cases

Trauma to the chest can result in cardiac damage, which maybe missed by clinical examination because of associated injuries.Routinely performed non-invasive tests may also be non-diagnostic.Tc-99m pyrophos-phate (PPi) tomography, in this study combinedwith T1-201, is a promising addition to non-invasive evaluation.In three patients with cardiac injury, this technique successfullydetected and localized myocardial necrosis.     

Haemophilia management: time to get personal?

Summary. The possibility of alloimmunization in patients receiving protein replacement therapy depends on (at least) three risk factors, which are necessary concomitantly but insufficient alone. The first is the degree of structural difference between the therapeutic protein and the patient’s own endogenous protein, if expressed. Such differences depend on the nature of the disease mutation and the pre‐mutation endogenous protein structure as well as on post‐translational changes and sequence‐engineered alterations in the therapeutic protein. Genetic variations in the recipients’ immune systems comprise the second set of risk determinants for deleterious immune responses. For example, the limited repertoire of MHC class II isomers encoded by a given person’s collection of HLA genes may or may not be able to present a ‘foreign’ peptide(s) produced from the therapeutic protein – following its internalization and proteolytic processing – on the surface of their antigen‐presenting cells (APCs). The third (and least characterized) variable is the presence or absence of immunologic ‘danger signals’ during the display of foreign‐peptide/MHC‐complexes on APCs. A choice between existing therapeutic products or the manufacture of new proteins, which may be less immunogenic in some patients or patient populations, may require prior definition of the first two of these variables. This leads then to the possibility of developing personalized therapies for disorders due to genetic deficiencies in endogenous proteins, such as haemophilia A and B. [Correction made after online publication 11 July 2011: several critical corrections have been made to the abstract].     

CARBOHYDRATE-DEFICIENT TRANSFERRIN AS A MARKER OF ALCOHOL INTAKE: A STUDY WITH HEALTHY SUBJECTS

This paper reports the results of a 3-week drinking experimentin 51 healthy male subjects, examining the value of %CDT (carbohydrate-deficienttransferring in the context of different levels of alcohol intake.All healthy persons were urine-tested drug-free and underwentdaily breath alcohol tests for the 7 days preceding, and duringthe whole 3 weeks of, the experiment. Subjects were dividedinto five groups, consuming different amounts of alcohol dailyover a 3-h period in the presence of the investigators. Thefive groups consisted of 10, 9, 10, 16 and 6 subjects respectivelyand consumed a daily dose of ethanol of 20, 40, 60, 80 and 80g respectively for 3 weeks. No significant changes in %CDT weredetected in most subjects, even in the 80 g alcohol-consuminggroups. The results suggest that CDT is not sensitive for thedetection of short-term heavy drinking by healthy subjects.     

Mosaics and haemophilia

Summary.  Some mosaic conditions may affect the haemophilia phenotype. Well-known instances include chromosomal mosaicism because of aneuploidy and pseudo-mosaicism because of varying patterns of X-chromosome inactivation. Chromosomal mosaicism in a chimera is a potential source of phenotypic variation. Gene mosaicism is commonplace. Its pattern and effect depend on the stage of development at which a mutation occurs. Proven or possible genetic mosaicism is an important consideration when predicting the likelihood of transmission of haemophilia to a future generation. A mosaic is an individual who has two or more cell lines, genetically different with regard to chromosomes or genes. As techniques improve and studies accumulate, mosaics are being found to be more common than hitherto believed. Some mosaic conditions may affect the phenotype of haemophilia in males and of the carrier state in females. Cells may be mosaic with regard to chromosomes , as in some instances of aneuploidy, and in chimeras, and in females owing to the pattern of X-chromosome inactivation. Cells may be mosaic with regard to new gene mutations . The pattern of mosaicism depends upon the stage in embryogenesis or in germ-cell formation in which the mutation arose.     

Conduct of clinical trials in developing countries

Research subjects in developing countries may be especially vulnerable to exploitation. Scrupulous care should be taken to maintain the basic principles of ethical trial conduct: the right of participants to make their own informed decisions, a favorable balance of benefit to risk, good trial design, candour about results, and, above all, use of honourable investigators. Involvement of local participants in planning a trial helps ensure both culturally-sensitive protocols and consents and also maximum benefit to patients and to local research infrastructure.     

CARBOHYDRATE-DEFICIENT TRANSFERRIN AS A SCREENING MARKER FOR DRINKING IN A GENERAL HOSPITAL POPULATION

We investigated the usefulness of the laboratory marker of alcoholconsumption carbohydrate-deficient transferrin (CDT) in 101consecutively admitted patients in a surgical and internal medicalward of a hospital in a rural wine-growing area. Four majoraspects were considered: the influence of liver disease, themethod of expression of CDT values (relative % vs absolute units/1),level and pattern of alcohol consumption and comparison with