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At least 19 recordsLinked to original sources
PubMed1978

Quantitative studies on the arrangement of human metaphase chromosomes. V. The association pattern of acrocentric chromosomes in human meningiomas after the loss of G and D chromosomes.

The association pattern was studied in 2715 mitoses of 90 meningiomas with different numbers of acrocentric chromosomes. In cells with monosomy 22, a significant increase of mitoses with associations was observed in comparison to cells with a normal karyotype. The number of associating acrocentric chromosomes was highly significantly increased. This surplus was not only caused by a highly significant increase of associating G chromosomes but also of D chromosomes. The loss of further acrocentric chromosomes had no significant influence on the number of mitoses with associations or the number of associating chromosomes. Based on the well-known correlations between the nucleolus organization and the association pattern, the results seem to indicate a compensation mechanism among the nucleoles organizing regions (NOR's) which keeps the supply of nucleolar material constant and simultaneously causes a higher association tendency between the remaining acrocentric chromosomes. The increase of associations in the 22 monosomic cells was interpreted as a overcompensation after the loss of only one NOR.

Cell Cycle↗
PubMed1979

Quantitative studies on the arrangement of human metaphase chromosomes. VII. The association pattern of acrocentric chromosomes in carriers of Robertsonian translocations and in their relatives with normal karyotypes.

The pattern of association of acrocentric chromosomes was examined in ten and five carriers of a 15/21 and a 13/14 Robertsonian translocation, respectively, and was compared with that of the same numbers of relatives with normal karyotypes. In the carriers of 15/21 translocation, the number of large associations (involving more than two acrocentrics) and the association frequencies for individual acrocentric chromosomes, were significantly higher than in the control group. The mean number of associations of the single homologs of the translocation chromosomes was much higher than that of the other acrocentrics. In the carriers of 13/14 translocations, only the association frequency for chromosome 13 was higher than in the normal relatives. The uninvolved chromosomes homologous to those involved in translocation showed an insignificant increase in associations in comparison with the other acrocentrics. These results suggest that some mechanism within the cells compensates for the effect of missing acrocentrics or of acrocentrics lacking NORs on the number of associations. The possible relations of this phenomenon to the activity of the nucleolus organizing regions are discussed.

Chromosome Banding↗
PubMed1979

Quantitative studies on the arrangement of human metaphase chromosomes. VI. The association pattern of acrocentric chromosomes in patients with trisomy 13.

The association pattern was studied in 1182 mitoses of 21 patients with trisomy 13 and in a control group. In addition, 173 trisomic mitoses were compared with the same number of diploid mitoses in a case of mosaicism. The number of mitoses with associations was no higher in the trisomic cells than in cells with normal karyotypes. Some differences were observed in the frequency of associations per cell and of the types of associations in the patient group and in the trisomic cells of the mosaic case. The number of associations in which more than two acrocentric chromosomes were involved was unexpectedly low in the cells with a supernumerary chromosome 13. The results are interpreted as suggesting the existence of a compensatory mechanism activated by the additional acrocentric chromosome.

Cell Nucleolus↗
PubMed1976

[Sequential staining for G- and C-banding of chromosomes in the analysis of the morphology of the short arms of human acrocentric chromosomes].

Sequential staining for G- and C-banding of acrocentric chromosomes of 8 persons showed that the large heterochromatin region occurred more frequently in chromosome 15 than in chromosomes 13 and 14, and in chromosome 22 more frequently than in chromosome 21. There proved to be no correlation between the size of the heterochromatic region and the short arm of the acrocentric chromosomes. The frequency of occurrence of the satellites in the 8 persons was approximately the same for all the acricentric pairs. The C-banded satellite region of the homologous chromosomes is often heteromorphic.

Chromosome Aberrations↗
PubMedDate not supplied

[Human acrocentric chromosomal associations in old age].

Associations of satellite chromosome fibres of acrocentric chromosomes of the DD, GG and DG types were studied in persons aged from 80 to 114 years. It was found that the value of P (probability of joining of satellite fibres of two chromosomes in a group) is considerably less than the corresponding value for persons aged from 20 to 48 years. It is supposed that the decrease of the frequency of association at senile age is caused by heterochromatization of satellite fibres in the 13th and 14 chromosome pairs.

Adult↗
PubMed1979

[Incorporation of H3-uridine in vitro into normal lymphocytes and those in cases of aberration of acrocentric chromosomes].

Literature data indicate that the formation of ribosomes is a basic function of the nucleolus. The formation of the nucleolus depends upon the function of the nucleolus organizing region (NOR). It was shown that in man the NOR locus is situated in secondary constrictions and adjacent segments of the short arms of acrocentric chromosomes of the D and G group. The presence of DNA sequences coding for 18 S and 28 S RNA i.e. ribosomal RNA (r-RNA), was demonstrated in the secondary constriction of acrocentric chromosomes using the RNA-DNA hybridization in situ method. The genes coding for 5 S RNA which is also a component of ribosomes, are located on other chromosomes. Therefore ribosome production should be considered a polygenic process, the genes situated in the NOR locus playing a basic role in its initiation. In cases of acrocentric chromosome aberration NOR "dosage" changes; in cases of regular trisomy there are 11 NOR "doses" instead of the normal 10, occurring in 5 pairs of group D and G chromosomes, in cases of translocation trisomy there are 9 such "doses" and in cases of balanced translocation carriers there are 8 "doses". Hence the following question: do changes in the NOR "dose" cause changes in ribosome production? Eventual changes should influence the intensity and/or the time course of r-RNA synthesis in cells stimulated to growth and differentiation . An approximate index for the study of this phenomenon is the 3H-uridine incorporation in an adequate experimental system. It seems that the most convenient model to study this phenomenon is the blastic transformation of lymphocytes induced by phytohaemagglutinin. This process has already been investigated in depth and is well known, the material being easily accessible. Venous blood was taken from 10 patients with 21 regular trisomy, 2 cases of 21 translocation trisomy and from 21 carriers of balanced translocations. Lymphocytes from 12 healthy persons with a normal karyotype served as controls. Lymphocytes in plasma were separated from whole blood and a routine macroculture was set up adding phaseoline of standardized mitogenic activity in the quantity 0.02 ml/ml of medium. The cells were incubated for 3, 6, 12, 24 and 48 hours. One hour before termination of the incubation period 1 microCi/ml 3H-uridine was added to the medium.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1977

Frequency of Ag-stained nucleolus organizer regions in the acrocentric chromosomes of man.

The Ag-stainability of the nucleolus organizer region (NOR) was studied in the acrocentric chromosomes identified by Q-banding of cultured lymphocytes in 51 karyotypically normal persons (31 males and 20 females). A consistent pattern of Ag-positive NORs was found in each individual. Ninety percent of individuals have a model number of 8--10 Ag-positive NORs per cell. The frequency of Ag-positive NORs is similar in all five acrocentrics. A statistically nonsignificant lower frequency is found in chromosome 22. Ag-negative NORs on both homologues were found in four cases. The observed frequency distribution of individuals with homozygous NOR-positive, heterozygous, and homozygous negative acrocentric chromosomes was in accordance with the Hardy-Weinberg law in all five pairs of the acrocentric chromosomes as well as in total. No sex difference was observed on our material.

Cell Nucleolus↗
PubMed1977

[Intersatellite connections of the human acrocentric chromosomes that participate in associations].

Intersatellite connections between acrocentric chromosomes in associations were revealed by the method of thermal ammoniacal silver staining. The associations were allotted to the corresponding groups on the basis of the number of chromosomes. Distribution of D- and G-chromosomes in associations was studied on the basis of 714 associations from 500 metaphase plates of 10 normal individuals. The hypotheses of hypergeometric, binomial, Poisson, uniform and exponential distribution laws of D- and G-chromosomes in associations were rejected. The hypothesis of normal distribution was not rejected. The principal characteristics of normal distribution law were found. The distribution law of the number of D- and G-chromosomes in associations was written analytically; the central moments and other characteristics were presented.

Adult↗
PubMed1977

N-band polymorphism of human acrocentric chromosomes and its relevance to satellite association.

With the aid of Q- and N-banding techniques we investigated the relationship between the length of satellite stalks, the appearance of N-bands and the frequency of satellite association of individual acrocentric chromosomes in the cells of seven individuals, including one male with a satellited and small Y-chromosomes. The appearance of N-bands, seemed to be a constant and characteristic property of individual acrocentric chromosomes, independent of the status of concentration of the chromosomes at metaphase. The homolog with longer satellite stalks had larger N-bands and participated in satellite association at a higher frequency than the one with shorter stalks. It appeared that N-bands were present along the whole length of the satellite stalk, the size of which could possibly reflect the amount of rDNA present in the nucleolar organizers in human chromosomes.

Chromosomes↗
PubMed1978

Satellite associations of human acrocentric chromosomes identified by trypsin treatment at metaphase.

In the present work 2526 metaphase plates were prepared from 28 normal adult individuals (12 male and 16 female) and then treated with the trypsin method in order to recognize the acrocentric chromosomes involved in the satellite associations. From our data it can be inferred that while the pattern of association of D--D, D--G and G--G groups seems to be random, there exists some preferential association, particularly between the pairs 13--14, 13--13, 13--21 and 21--21. This non-random participation of the acrocentric chromosomes could fit with the new concepts of interphase/metaphase organization of the chromatin fibre.

Adult↗
PubMed1979

Populational polymorphisms in silver staining of nucleolus organizer regions (NORs) in human acrocentric chromosomes.

The Ag stainability of the nucleolus organizer region (NOR) was studied in the acrocentric chromosomes identified by Q banding of cultured lymphocytes in 41 karyotypically normal persons (33 males and 8 females) originating from southeast Estonia. The data obtained are compared with those established earlier for a combined Vienna-Ulm population of 51 karyotypically normal persons (see Mikelsaar et al., 1977a). Significant differences between the two populations in the frequency and patterns of Ag-positive NORs were found. The following findings were most striking: the frequency of Ag-positive NORs in chromosome 14 and in the totals was significantly lower in the Estonian population than in the Vienna-Ulm population (P less than 0.01). The average modal number of Ag-positive NORs per individual was 7.8 in the Estonian population and 8.7 in the Vienna-Ulm sample (P less than 0.01). If the data of the two populations were combined the frequency of positive NORs was significantly (P less than 0.05) lower in chromosome 22 than in 13, 15, and 21, but not 14.

Cells, Cultured↗
PubMed1979

Prominent acrocentric chromosome satellites in child patients with mental retardation or psychiatric disorders; no IQ-satellite size correlation.

Child patients with mental retardation or psychiatric disorders were selected for the presence of prominent acrocentric chromosome satellites and highest or lowest IQ scores. No correlation was found between IQ scores, of which eleven were below IQ 54 and 16 above IQ 68, and the length of acrocentric short arm, satellite, stalk, or short arm material below the stalk. Conventional staining, quinacrine fluorescence, C banding and ammoniacal silver staining revealed the apparent same acrocentric short arm variation between patient and one parent in eight families studied. These findings suggest that the satellite variants were truly normal variants and not etiologically related to the developmental disorders seen in the patients.

Child↗
PubMed1975

Variation in human acrocentric chromosomes with acridine orange reverse banding.

Twenty-five normal subjects were studied by acridine orange reverse (RFA) banding in order to obtain a preliminary estimate of the type and frequency of variations in color and length. Color variations were classified into 1 of 6 colors and size variations into 1 of 5 levels. The same cells were also studied by Q banding. Acridine orange reverse banding was found to be more useful than Q banding for characterizing variations in chromosomes 14, 15, 21 and 22. In addition, it was found that there was no consistent relationship between pale or bright Q banding and the various colors observed with RFA banding. For the optimal characterization of a chromosomal variation, multiple banding technics, including RFA banding, are necessary.

Acridines↗
PubMed1977

Frequency of RFA colour polymorphisms of human acrocentric chromosomes in caucasians: interrelationship with QFQ polymorphisms.

One hundred normal caucasians were studied by sequential QFQ and RFA in order to estimate the type and frequency of variation. Colour variants were classified into 1 of 6 colours by RFA and intensity variations into 1 of 5 levels by QFQ. The interrelationship between QFQ and RFA variants was also examined. It was found that there was no consistent relationship between negative or brilliant QFQ variants and the various colours observed with RFA. RFA colour polymorphisms for chromosomes 13, 14, 15, 21 and 22 were 33.0, 38.0, 28.0, 50.0 and 24.5% while QFQ frequencies were 56.5, 10.0, 10.0, 15.5 and 10.0% respectively. RFA is especially useful in studying the inheritance of chromosome 21.

Adult↗