Quantitative measurements of the nuclear localisation of the ABL and BCR genes and the distance between them were performed in randomly oriented bone marrow cells of control donors and patients with chronic myeloid leukaemia (CML). Most ABL and BCR genes (75%) are located at a distance of 20-65% of the local radius from the nuclear centre to the nuclear membrane. A chimeric BCR-ABL gene located on a derivative chromosome 22 resulting from t(9;22)(q34;q11) [the so-called Philadelphia (Ph) chromosome] as well as the intact ABL and BCR genes of patients suffering from chronic myeloid leukaemia are also located mostly in this region, which has a mean thickness of 2 microns in bone marrow cells. We have not found any significant differences in the location of the two genes in the G1 and G2 phases of the cell cycle, nor between bone marrow cells and stimulated lymphocytes. Irradiation of lymphocytes with a dose of 5 Gy of gamma-rays results in a shift of both genes to the central region of the nucleus (0-20% of the radius distant from the nuclear centre) in about 15% of the cells. The minimum distance between one ABL and one BCR gene is less than 1 micron in 47.5% of bone marrow cells of control donors. Such a small distance is found between homologous ABL and between homologous BCR genes in only 8.1% and 8.4% of cells, respectively. It is possible that the relative closeness of nonhomologous ABL and BCR genes in interphase nuclei of bone marrow cells could facilitate translocation between these genes. In 16.4% of bone marrow cells one ABL and one BCR gene are juxtaposed (the distance between them varies from 0-0.5 micron) and simulate the Ph chromosome. This juxtaposition is the result of the projection of two genes located one above another into a plane, as follows from the probability calculation.
The case presented here illustrates a protothecal infection caused by Prototheca
wickerhamii in a paediatric haematopoietic stem cell recipient followed by a review of the
literature of all 13 paediatric cases published since 1980. Protothecosis is a rare disease caused
by algae, not described in this setting before. Infection was proven additionally post-mortem from
peritoneal dialysis fluid. Even though no death of a paediatric patient due to this infection has
been reported and the mortality rate associated with protothecosis is low, our patient died from
multiorgan failure as a result of numerous post-transplant complications and a strain of cultivated
alga that was highly resistant to antifungal agents. Prototheca spp. show various
susceptibility profiles, and there is no direct correlation between in vitro
activity and clinical response. There are different treatment regimens described but there are no
clear published guidelines of specific therapy of protothecosis. Paediatric cases were successfully
treated mostly with amphotericin B and azoles. As the number of immunocompromised patients
increases, it is necessary to think more about unusual pathogens such as
Prototheca.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.