Evidence of massive leukemic progenitor expansion in blood during molecular recurrence after TKI discontinuation in chronic myeloid leukemia (CML)

ABSTRACTChronic myeloid leukemia (CML) represents one of the major success stories of targeted therapies of the 21st century with the use of tyrosine kinase inhibitors (TKIs). Following discontinuation of TKIs in deep molecular remission context, at least half of the patients experience molecular relapse. Cellular events occurring during this phase are not yet established. In this work, we show a massive amplification of clonogenic progenitors or CFCs (colony-forming cells) in the peripheral blood of patients in molecular recurrence after a TKI discontinuation. We demonstrate, by qRT-PCR analysis on individual and pooled CFCs, that leukemic clonogenic progenitor expansion in the peripheral blood represents the first cellular event before any evidence of cytological change. These findings also suggest that the amplification of the leukemic clone during the first stages of CML takes place not only in the bone marrow but also in the peripheral blood.

Cytological features of pig oocytes in the process of spontaneous maturation

Aim. The study was aimed at determining the cytological changes, related to the germinal vesicle (GV) of porcine oocyte during the follicular maturation. Methods. The ovaries were classifi ed according to the estrous cycle phase, judging by the status of yellow bodies and follicles. The oocytes were isolated from each animal using dominating and atresiated follicles separately. The oocytes were used to prepare whole mounts by a specially designed express-method, which is thermal fi xation (about 95 °С) and their further transfer into the medium for clarifi cation. The whole procedure of preparing the mount from one oocyte or their group lasted for about 10 min. The microscopic studies were conducted using the phase contrast. A total of 831 oocytes were studied. Results. It was established that sow oocytes had eccentric location of GV which may be found in oocytes from early antral follicles. This condition is kept until the beginning of meiosis restoration and GV destruction. The nucleolus is also located eccentrically. Another relevant cytological change was gradual condensation of chromatin around the nucleolus, starting from separate clots on its surface and further formation of circular structures. Conclusions. Contrary to laboratory rodents, GV in porcine oocytes has eccentric localization, which is set even in early antral follicles and remains until the beginning of meiosis restoration. The process of chromatin transformation was found to be its gradual condensation around the nucleolus which may be defi ned as a nucleolus complex.

Effect of cycloheximide on the freezing tolerance and ultrastructure of cortical parenchyma cells from mulberry twigs

Experiments were performed using cycloheximide (CHI) on cortical parenchyma cells from mulberry twigs (Morus bombyciz cv. Gorogi) to understand the relationship between the sequence of cytological changes suggesting replacement of the plasmamembrane and the rapid increase in freezing tolerance. Cortical cells from twigs collected on October 16 and 27, which were hardy to −10 and −15 °C, respectively, were still alive after cooling to −70 °C if they had been exposed to −3 °C for 10 to 12 days. In these hardened cells, appearance of microvesicles (MVs) in the peripheral cytoplasm and fusion of these MVs with plasmamembrane were characteristically observed. Neither cytological change nor increase of freezing tolerance was observed in cells treated by CHI before their exposure to −3 °C for 10 to 12 days. However, the suppression of such changes by CHI treatment was effective only in cells which were hardy at −10 to −15 °C and not in the cells of twigs collected on November 4, which were hardy to −20 °C. Consequently, synthesis of some functional proteins during hardening was required for the further development of freezing tolerance, and synthesis had been accomplished before the cells became hardy to −20 °C. Ultrastructural changes brought about by CHI treatment suggest that synthesis of some functional proteins related to the presumed changes of plasmamembrane occurs during hardening.

Comparative embryology of Stipa elmeri (Gramineae)

The ovule of Stipa elmeri is bitegmetic, hemianatropous, and pseudocrassinucellate. The micropyle is formed by the inner integument. The inner integument is two cells thick except at the micropyle. Its inner layer is persistent and safraninophilic, and some of its cells develop secondary walls. A cuticle is also present outside the inner integument. The outer integument is two cells thick except for a bump four or five cells thick at the chalazal end. At later stages of development, the outer integument breaks down except at the chalazal end. As the ovule develops, it undergoes changes in orientation as a result of growth pattern changes in the nucellus. A multiple protoderm is present in some parts of the nucellus.The outer layer of the nucellus persists to later stages of development and is covered by a cuticle. Fruit wall changes during development are (1) formation of a thick, unlignified wall on the protoderm, (2) elongation of cells lining the locule, and (3) decrease in number of cells. Megagametophyte development is normal and the antipodals proliferate. Before fertilization, both synergids undergo cytological change and one decreases in size. The pollen tube appears to enter at the base of the larger synergid. The endosperm is free nuclear at first but then becomes cellular. At later stages of development, the outer layer of the endosperm is meristematic. On the basis of embryological data, the following phenetic series can be constructed: S. elmeri → S. lemmonii – S. hendersonii → S. tortilis → Oryzopsis miliacea. Available embryological data does not indicate a close relationship between the Gramineae and the Juncaceae or Cyperaceae.

Adenocarcinomas of the Intestine Induced in Syrian Hamsters by N-methyl-N-nitrosourea

The adenocarcinomas of the intestine induced in Syrian hamsters by N-methyl-N-nitrosourea (NMU) were of two histological types, superficial and intestinal. These types had distinctive characteristics regarding pattern, cytological features, secretion of mucus, and mode of growth. The histological changes induced by NMU in the mucosa of the small intestine differed from what has been described in enzootic intestinal adenocarcinoma and proliferative ileitis of Syrian hamsters. NMU produced alteration in the villous architecture and cytological change in the absorptive cells. There was marked shortening of the villi and reduced thickness of the mucosa. The villous absorptive cells were large and cuboidal with centrally placed nuclei.

A CYTOCHEMICAL DESCRIPTION OF THE MULTIPLICATION OF MENGOVIRUS IN L-929 CELLS

A correlation of cytochemical changes with virus production has been studied in L cells infected with Mengovirus. After a latent period of about 2 hours, virus was produced rapidly, reaching maximum titers of up to 12,000 particles per cell in 6 to 8 hours. The earliest cytological change was in the nucleus and consisted of a slight condensation of chromatin. There is no evidence, however, for the multiplication of either the viral RNA or protein in the nucleus. RNA, of high molecular weight, accumulated in the perinuclear area of the cytoplasm and was later found in inclusions. The perinuclear RNA was digestible with RNase and may be located in or on ribosomes. The inclusion RNA was resistant to RNase but could be removed by pepsin or potassium permanganate; it is probably in completed virus particles. Viral antigen was first observed in a perinuclear location and later in the above-mentioned inclusions. Although the viral protein contains appreciable amounts of arginine and lysine, it is not a basic protein of the histone type. Phase-contrast microscopy of living cells clearly demonstrated the role of the inclusions in release of virus from infected cells. A comparison is made between these cytological changes in Mengo-infected cells and those which have been found by other workers in polio-infected cells. There are many very similar changes.