[Principle of the supramolecular stacking of the cellular deoxyribonucleoprotein complex]. / O printsipe nadmolekulianoi ukladki dezoksiribonukleoproteidnogo kompleksa kletki.

Using cytofluorimetry with acridine orange staining and a modified thermal denaturation technique of cellular DNP, it has been shown that chromatin melting profiles of normal human nuclei (from lymphocytes and granulocytes) have distinct regularities. It is believed that these regularities reflect specific supramolecular chromatin organization. Parallel comparative analysis performed using electrophoretic fractionation and isoelectric focussing of nuclear proteins has revealed that: 1) peculiarities of chromatin melting profiles are independent of the quantity and molecular weights of chromatin proteins; 2) the lack of principal differences in chromatin melting profiles and the data on isoelectric points of nuclear proteins of granulocytes and lymphocytes from the same patient indicate that specific supramolecular organization of DNP-complex depends on the chromatin protein charge.

[Structure of the interphase chromatin in the peripheral blood cells of children with acute lympholeukemia and in their healthy parents]. / Struktura interfaznogo khromatina kletok perfericheskoi krovi u detei s ostrym limfoleikozom i u ikh zdorovykh roditelei.

It has been shown using labelled modified AO cytofluorometry of DNP cellular thermal denaturation that the melting profiles of peripheral blood cellular chromatin in children with acute lympholeukemia (ALL) were of strictly individual, "unclassifiable" nature and were similar to those of their mothers but different from those of their fathers and healthy people, which seems in favour of a possible connection between the disease under study and the peculiarities of the mother's genotype. Similar types of deviations have been found in the structure of interphase chromatin of healthy parents of children with ALL. Such a combination of changes in the parents' genotype may prove unfavourable, increasing the birth rate of neonates with a genetic predisposition to the disease in question.

[Interphase chromatin of the peripheral blood cells of patients with a chronic form of myeloid leukemia (Ph+)]. / Interfaznyi khromatin kletok perifericheskoi krovi u bol'nykh s khronicheskoi formoi mieloidnogo leikoza (Ph+).

It was shown with labeled AO cytofluorometry using the authors' modification of DNP cell thermal denaturation that in untreated patients with chronic myeloid leukemia (CML) in the blast crisis phase, the melting profiles of peripheral blood cell chromatin were "unclassified", strictly individual in nature (unlike the identical parameter in healthy subjects) that may attest to regulatory disturbances of the genetic apparatus. The demonstration of the "normalization" of the melting profiles of chromatin in CML patients during the clinico-hematological compensation of the disease makes it possible to suggest that luminescent fluorometry (in the authors' modification of DNP cell thermal denaturation) should be used for the treatment of hemoblastoses in order to study the genesis and time-course of the diseases running their course with remissions and as criterion of drug therapy of these diseases.

[Interphase chromatin in lymphocytes in sex differentiation disorders]. / Interfaznyi khromatin limfotsitov u bol'nykh s narushennoi differentsirovkoi pola.

Interphase chromatin of peripheral lymphocytes was studied in patients aged 6 to 20 years with Turner and Morris's syndromes by AO labeled fluorometry using the authors' modification of DNP cell thermal denaturation. It was shown that the lymphocyte chromatin melting profiles represent the curves with seven maxima at the following temperatures: 47 degrees, 55 degrees, 65 (+/- 2)degrees, 78 (+/- 1)degrees, 82, 88 (+/- 1)degrees, 92 (+/- 2)degrees C (P less than 0.01). There were no statistically significant differences between clinically and karyotypically different groups either in the parallelism of the melting profiles or in the fluorescence intensity of AO connected with cell DNP. In the male control group, the similar curve was obtained for lymphocyte chromatin in 25 and for normal human spermatozoa in 100% of cases, i.e. deviation specificity was revealed in the lymphocyte melting profiles, from a "classical" normal variant to the so-called male variant with sex differentiation breaks (Turner, Morris and Klinefelter's syndromes). Possible cytogenetic mechanisms of breaks are discussed.

[Interphase chromatin of human cells with diploid and haploid genomes]. / Interfaznyi khromatin kletok cheloveka s diploidnym i gaploidnym genomom.

A study was made of the chromatin structure of mature sperm cells from healthy males aged 25 to 40 using fluorescent microscopy and acridine orange staining according to the DNP cell thermal denaturation technique modified by the authors. It was shown that normal human sperm cell chromatin melting profiles represent uniform curves with maxima in the following temperature ranges: 43 (+/- 2) degrees, 55 (+/- 1) degrees, 67 (+/- 2) degrees, 77 (+/- 1) degrees, 82 (+/- 0.5) degrees, 89 (+/- 1) degrees, 92 (+/- 2) degrees (P less than 0.01), that are identical to those obtained with lymphocytes of healthy males with certain deviations from the standard normal variant. No heteromorphism was revealed in the sperm cell chromatin. Marked polymorphism in the chromatin structure occurs but at the diploid cell level. A 10-time decrease in the fluorescence of AO bound with sperm cell chromatin as compared to F530 AO bound with lymphocyte chromatin structure of the same individual supports the data on the over condensation of sperm cell nuclear chromatin as compared to that in lymphocytes.

Lymphocyte interphase chromatin in healthy subjects, patients with Down's syndrome, and their parents and sibs.

A study of the interphase chromatin structure of lymphocytes in healthy subjects, patients with Down's syndrome, and their parents and sibs was carried out by AO labelled fluorometry using our modification of DNP cell thermal denaturation. Analysis by the Sperry Univac 90/30-B computer showed that in 40% of healthy subjects the lymphocyte chromatin melting profiles had a regularly repeated curve with six (seven) maxima at definite temperatures. In the remaining 60% some regularly repeated deviations were present and were correlated with the sex of the subject examined. There were five subgroups in the female group and seven subgroups in the male group. In 97% of patients with Down's syndrome the lymphocyte chromatin melting profiles gave curves with three maxima at temperatures of 65, 85, and 92 degrees C (+/- 2 degrees). Maxima at 78 and 45 degrees C were absent. In 80% of the mothers of probands with Down's syndrome and in 30% of female sibships, lymphocyte melting profiles also produced curves with three maxima: 65, 85, and 92 degrees C (+/- 2 degrees). In view of the fact that similar changes were observed in mothers and female sibs only, we propose that some women may have genotypical peculiarities which may possibly contribute to the origin of this chromosome pathology.

[Structure of interphase chromatin of diploid and trisomal human cells studied by the technic of thermal denaturation in media of low ionic strength]. / Struktura interfaznogo khromatine diploidnykh i trisomnykh kletok cheloveka, issledovannaia metodom termicheskoí denaturatsii v sredakh s nizkoi ionnoi siloi.

Fluorescent microscopy with the use of acridine orange has shown on a short-term human cell culture that the melting profiles of intact lymphocytes from normal subjects present the curves with maxima (F530) within a definite temperature range: 45, 65, 78, 85, 88 and 92 degrees C (+/- degrees C). The melting profiles of lymphocytes from patients with the Down syndrome present the curves with maxima at 65, 85, 88 and 92 degrees C. The melting of human cells in low ionic strength media as compared with physiological one causes the disappearance of the maxima on the chromatin melting curve and disappearance of the difference in the melting profiles of cell chromatin from normal subjects and patients. The data obtained allowed the conclusion that the use of acridine orange reveals the specificity of supermolecular organization of cell DNA complexes which is retained only under the conditions of physiological ionic strength medium. The organization of chromatin structure in patients with the Down syndrome was found to be changed as compared with controls.

[Computer classification of the fusion profiles of human lymphocyte interphase chromatin]. / Klassifikatsiia profilei plavleniia interfaznogo khromatina limfotsitov cheloveka, poluchennaia s pomoshch'iu EVM.

AO fluorescent microscopy coupled with thermal denaturation of DNP cells as modified by the authors was used to study the structure of lymphocyte interphase chromatin from 164 normal persons. Analysis of the data processed by means of a Sperry Univac Computer 90/30 has demonstrated that in 40% of the cases, the melting profiles of DNP cells from normal persons represent, irrespective of the sex, a complicated but consistently repeated curve with 6 peaks at certain temperatures, i.e. that different test subjects have a pronounced "similarity" in the characteristics discussed. In the remaining cases, there have been recorded diverse but consistent deviations that correlated with the sex of the test subjects. No peak at a temperature of 85 degrees and its appearance at 82 degrees C were the most frequent deviations seen in the male group. There have been obtained altogether 5 subgroups for females and 7 subgroups for males. Thus an attempt has been made to classify for the first time the melting profiles of DNP cells from normal persons with the use of computer.

[Melting profiles for lymphocyte chromatin of healthy subjects and Down's disease patients obtained by the technic of cellular DNA absorption in ultraviolet light]. / Profili plavleniia khromatina limfotsitov zdorovykh liudei i bol'nykh bolezn'iu Dauna, poluchennye metodom pogloshcheniia DNK kletok v ul'trafiolete.

Integral values of optical density (E260) were obtained for lymphocyte nuclei from normal people and those suffering from Down's syndrome during the melting of cells in media of varying ionic strength (0.15 M NaCl - control; 0.015, 0.0015 and 0.00015 M NaCl - experimental). The differences in E260 were obtained only during the melting of cells in 0.15 M NaCl. In lymphocytes from normal people, the distinctly reproducible hyperchromic effect was detected from 78 degrees (up to 35--40%), reaching the plateau by 96 degrees C (P less than 0.01). In identical conditions, the hyperchronic effect on aneuploid cells was revealed only after 98 degrees C (P less than 0.01). The data presented confirm the authors' concept of the greater condensation of aneuploidic genome.

[Change in the structure of fibroblast chromatin in a patient with Down's disease and his mother]. / Izmenenie struktury khromatina fibroblastov u bol'nogo bolezn'iu Dauna i ego materi.

A clear-cut difference between chromatin melting curves of cells from the patient with Down's disease and his mother and ones from healthy individuals and the proband's father was shown by fluorescence microscopy and acridine orange staining on human fibroblasts incubated in autologous serum. These data suggest the presence of an obvious genetic correlation between phenotypically healthy mother and her sick child. The identity of the chromatin structure of the patients detected both on lymphocytes and other type of cells, human fibroblasts, allows a suggestion that the phenomenon of the altered chromatin structure is typical generally of the given individual's tissues. Certain changes in the cell chromatin structure are mediated by the effect of autologous serum.

[Blood serum as a factor of chromatin condensation in trisomy-21 (Down's syndrome)]. / Syvorotka krovi kak faktor kontsentratsii khromatina pri trisomii-21 (sindrom Dauna).

The influence of blood sera from patients with Down's syndrome and healthy ones, and different serum fractions on the structure of the deoxyribonucleoprotein systems (DNP-system) has been studied. It was demonstrated that non-fractionated sera of the patients produce a condensation effect on the DNP-system in contradistinction to the sera from healthy people. The analysis of the action of single serum fractions showed that different condensation effect results from the activity of high molecular nondialysable thermosensitive components whose action disappears at gel-filtration of serum proteins. A possibility of the humoral control over chromatin structural organization in vivo is discussed in terms of the evidence on the similarity of serum proteins and chromosomal nonhistone proteins.

[State of cerebral neuronal nuclear chromatin during multimodal stimuli to the body]. / Sostoianie iadernogo khromatina neironov golovnogo mozga pri raznomodal'nykh vozdeistviiakh na organizm.

The state of nuclear DNA, revealed by the microfluorometric method, changed unequally in conditions of dissimilar afferentation in different classes of the neurones in the neocortex and the hippocampal dentate fascia. It may be assumed that the examined classes of cells (large pyramids and stellate neurones of the sensorimotor zone of the cerebral cortex and the granular cells of the dentate fascia of the hippocampus) possess a different structural functional organization of genome. This probably accounts for the peculiarities of their functioning.

[Analysis of changes in the structural state of chromatin in Down's disease]. / K analizu izmenennogo strukturnogo sostoianiia khromatina pri bolezni Dauna.

Dependence of optic density (lambda = 260 nm) of human lymphocyte nuclear chromatin on temperature under normal conditions and in Down's disease was studied. The low temperature (t approximately 70 degrees C) absorption maximum, absent in the nuclei of lymphocytes in patients with Down's disease, was characteristic of the lymphocyte nuclei of healthy donors. Analysis of the mentioned correlation for individual regions of the nucleus demonstrated the presence of at least two types of regions, i.e. with and without the low temperature absorption maximum. There were more regions of the latter type in Down's disease in comparison with the normal.

The structure of the human cell interphase chromatin in the mosaic form of Down's disease.

In an earlier publication we reported that, by using fluorescent microscopy with acridine orange (AO), we detected certain changes in the structure and function of interphase nuclear chromatin of peripheral blood lymphocytes of subjects with Down's disease (Fedorova, Inshakova and Spitkovsky, 1975). By employing the same method with additional thermal action on the cells studied it was shown that some of these changes were conditioned by the effect of the blood serum from a person with Down's syndrome (Fedorova and Spitkovsky, 1976). The purpose of the present work was to investigate the structure of the interphase chromatin of both disomic and trisomic human cells residing in the same serum, that is, in mosaic subjects. Small lymphocytes in the peripheral blood of mosaic mongols were selected for study, complete trisomic mongols and healthy subjects being used as controls.

[Structure of interphase chromatin in patients with Down's syndrome and their mothers]. / Strukture interfaznogo khromatina u bol'nykh s sindromom Dauna i ikh materei

A method of fluorescent microscopy with the aid of acridine orange was applied in these studies; some features of the changes in the structure of interphasic chromatin characteristic of their sick children were revealed on the short-term cultures of lymphoyctes obtained from the mothers with children suffering from Down's syndrome. Sibling girls also displayed deviations similar to the changes revealed in their mothers. The data obtained permit to suppose the existence of a definite population of women, peculiarities of whose genotype promoted the appearance on the structural chromatin organization was revealed only in the mothers and sibling girls it is suggested that the mentioned genotype peculiarities were hereditary and connected with genes (or certain chromatin areas) limited by sex.

[Reversibility of structural changes in the chromatin of peripheral blood lymphocyte interphase nuclei in patients suffering Down's disease under influence of serum from healthy subjects]. / Obratimost' pod vliianiem syvorotki zdorovog cheloveka strukturnykh izmenenii khromatina interfaznykh iader limfotsitov perifericheskoi krovi u bol'nykh, stradaiushchikh bolezn'iu Dauna

By using fluorescent microscopy and acridine orange staining it has been shown in the studies on a short-term human cell culture that the cellular chromatin DNA melting curve at the temperature range of 78--85 degrees C depends on changing conditions of the environment, i. e. on the composition of the blood serum.

[Lymphocyte chromatin changes in Down's disease detected by heat denaturation]. / Izmeneniia khromatina limfotsitov pri bolezni Dauna, vyiavlennye metodom termicheskoi denaturatsii

By using fluorescent microscopy and acridine orange staining it was shown in the studies on short-term culture of human cells that the melting patterns of chromatin DNA of intact lymphocytes of healthy individuals represented the curves with 6 maxima (F530) at the temperature ranges of 45 degrees C, 65 degrees C, 85 degrees C, and 92 degrees C (P less than 0.01). The melting patterns of lymphocytes from patients with Down's disease represented curves with 4 maxima at the temperature ranges of 65 degrees C, 85 degrees C, 88 degrees C, 92 degrees C (P less than 0.01). No decline in the fluorescence intensity at the temperature intervals of 78 degrees C-85 degrees C was apparently due to a greater degree of condensation of definite regions of the trisomal cell chromatin complex. Possible mechanisms accounting for structural readjustments of the interphasic human lymphocyte chromatin occurring under thermal effects are discussed.

Chromatin structure in Down's syndrome.

In the chromatin of patients with Down's syndrome, changes are shown to occur in a short-term lymphocyte culture of the human peripheral blood. Some of them are induced by the patient's blood serum and are reversible when this is replaced by normal serum. A 100-fold dilution of the blood serum taken in subjects with Down's syndrome does not produce any changes in the structure of the lymphocyte chromatin of the patients. A similar procedure with the blood serum of healthy donors resulted in a drastic activation of their lymphocyte chromatin. These experiments, and investigations on the effect produced by the blood serum on the model desoxyribonucleoprotein systems, support the suggestion that the changed state of the chromatin in subjects with Down's syndrome is caused by a complex set of components contained in the blood serum, whose degree of dissociation deviates from the normal.

[The comparative analysis of interaction between acridine orange and DNA-containing systems]. / Sravnitel'nyi analiz vzaimodeistviia akridinovogo oranzhevogo s DNK-soderzhashchimi sistemami

The interaction between acridine orange (AO) and diluted and concentrated solutions of DNA, DNP systems and chromatin suspension at the physiologic ionic strength was investigated. The effect of AO on DNP systems was also investigated. It was shown that highest possible number of AO molecules bound to DNA made up 70% of the total number of nucleotides. The model of AO binding to DNA is proposed and used for calculation of constants of stronger and weaker AO-binding capacities equal to 6-10(6) M-1 and 1,7-10(5) M-1, respectively. The AO-DNA binding constants in DNP-complex are five as low. The primary number of binding sites in chromatin suspension made up 10% of the corresponding sites in DNA and increased as AO was adsorbed. AO induced the supercontraction of oriented DNP systems at the physiologic ionic strength and the appearance of the low-temperature melting hump.