Increase In Frequency Of Abnormalities Research Articles

Flow Cytometric Analysis of TCR Vβ Repertoire in Patients with 22q11.2 Deletion Syndrome

In 22q11.2 deletion patients, the normal decrease in T lymphocyte counts after 1-2 years is blunted such that relatively T lymphocyte numbers increase over early childhood, probably via post-thymic expansion of peripheral lymphocytes. This may leave less T lymphocyte receptor (TCR) diversity than when derived from naive thymic emigrants. We analysed TCR Vβ repertoire on 27 22q11.2 chromosome deletion patients. No patient had infection at sampling. CD3(+) CD4(+) recent thymic emigrants (RTEs) were identified by CD45RA and CD31 expression. TCR Vβ repertoire was determined using four-colour flow cytometry. Patients and controls showed significant TCR Vβ family usage differences between CD3(+) CD4(+) and CD3(+) CD4(-) T lymphocyte subpopulations. Vβ family abnormalities (±3 SD of controls) were identified in 18/27 (67%) patients and 12/47 (25%) controls. In patients, the magnitude of expansions was increased, with some Vβ families representing 37% of the cells present in the subpopulations. There was a significant increase in frequency of abnormalities in CD3(+) CD4(+) (P < 0.001) and CD3(+) CD4(-) T lymphocytes (P < 0.05) in patients. A total of 11/16 patients had an abnormal CD4(+) CD25(Bright) TCR Vβ repertoire. There was no difference in expansions/contractions between CD4(+) CD25(Bright) and CD4(+) T lymphocyte repertoires (P = 0.575) for individual patients but significant differences in expansions/contractions between CD4(+) CD25(Bright) and CD8(+) T lymphocytes repertoires (P = 0.011). There was bias in Vβ usage between CD3(+) CD4(+) and CD3(+) CD4(-) T lymphocyte subsets. A total of 67% patients had TCR Vβ repertoire abnormalities, with a trend towards increased repertoire abnormalities with fewer RTEs, suggesting thymic output plays an important role in TCR repertoire diversity. There was no correlation between skewed repertoire and symptoms of infection or autoimmunity.

Cytology of Development of Abnormal Endosperm in Philippine Makapuno Coconuts

SUMMARYThe cytology of development of the buttery kernel (endosperm) in the Philippine makapuno coconuts has been studied. Though the first formed cellular endosperm is predominantly triploid, higher levels and grades of ploidy like 6 n, 9 n, 12 n, 24 n and 48 n (and above) characterise the maturing endosperm. The cytological situation in early stages of the makapuno endosperm is comparable to that in other coconut varieties, particularly the dwarf coconuts with which they share the relatively higher levels of polyploidy, presence of 2 n and 9 n nuclei and the greater frequency of mitotic abnormalities including considerable stickiness of chromosomes.The later stages of development of the makapuno endosperm characterised by unlimited growth and proliferation, accompanied by high polyploidy, increase in frequency of abnormalities, cessation of normal mitosis, onset of amitosis, attainment of high nuclear polymorphism, appearance of characteristic cell inclusions, etc. followed by degeneration of the nuclei...