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Biomedical subjects

O J Miller

Publications and source records attributed to O J Miller.

At least 91 records · Page 5Linked to original sources
PubMed1978

Nucleolus organizer activity and the origin of Robertsonian translocations.

Chromosomes with active nucleolus organizer regions (NOR's) were identified by combined Q-banding (in some cases), and silver staining in mouse cell lines. NOR-bearing chromosomes were overrepresented among the chromosomes involved in Robertsonian translocations in LM(TK-), A9, and RAG cell lines. Usually only one NOR-bearing chromosome was seen in any biarmed chromosome; relatively few contained two NOR-bearing chromosomes. Thus the nucleolus plays an important role, but nucleolar fusion is relatively unimportant, in the origin of Robertsonian translocations in the mouse.

Animals↗
PubMed1978

Human tumor and rodent-human hybrid cells with an increased number of active human NORs.

A human fibrosarcoma line, HT1080-6TG, with a near diploid number of chromosomes, has an average of 7.3 chromosomes with an Ag-stained nucleolus organizer region (NOR). Cells of this line with an increased number of chromosomes have an increased number of Ag-stained NORs. This cell line has been used as the human parent in constructing mouse-human and rat-human hybrids that segregate rodent chromosomes. The hybrid ccell lines, which have 100 or more chromosomes per cell, show a proportionate increase in the number of Ag-stained NORs (means, 11.4--16.8). The frequency of association of acrocentric chromosomes increases in a similar fashion. There is no evidence of inactivation of human NORs in these cells.

Animals↗
PubMed1978

Congenital chromosome anomalies.

The introduction of chromosome banding techniques has led to the detection of a greatly increased number of congenital chromosome anomalies, especially those involving duplication and/or deficiency of short segments of chromosomes. Of most widespread use are the general banding techniques: Q-, G- and R-banding. Special staining methods provide help in certain cases. These include C-banding, G11 staining of some C-bands, Ag-staining of active ribosomal RNA gene clusters, differential staining of sister chromatids and differential staining of early or late replicating bands. Every banding method that can be produced by a fluorescent or nonfluorescent dye can be duplicated by the use of antinucleoside antibodies, providing strong support for the idea that the organization of DNA of particular nucleotide base composition and sequence is responsible for chromosome banding. As a result of the application of banding methods, a wealth of structural chromosmoe changes have been detected. In the balanced form, as translocations or inversions, these may have no effect on their carrier. However, such carriers have a markedly increased risk of having children with congenital chromosome anomalies. Most of these can be diagnosed prenatally using the generally available banding techniques.

Chromosome Aberrations↗
PubMed1977

Preferential derivation of abnormal human G-group-like chromosomes from chromosome 15.

The marked binding of antibodies specific for 5-methylcytidine to the short arm of chromosome 15 distinguishes this chromosome from the other human acrocentrics. This method has been used to study over 60 individuals including 12 who did not have Down's syndrome, but who did have an extra G-group sized acrocentric chromosome. In six cases the extra chromosome did not show intensive binding of anti-5-methylcytidine. In the other six cases, the extra chromosome contained a 5-methylcytidine rich band at each end indicating that both ends were derived from chromosome 15 and contained centromeric heterochromatin normally present on the short arm of chromosome 15. The duplication of short arm material in the abnormal chromosomes was confirmed in all cases by quinacrine staining, nucleolar organizer (Ag-AS) staining or C-banding. In three cases, the abnormal chromosome appeared to arise from two different chromosomes 15. Several possible mechanisms for the production of the abnormal chromosome are discussed. The individuals with this abnormal chromosome all showed some degree of mental retardation, but few common physical findings.

Adult↗
PubMed1977

Increased intracellular phosphoribosylpyrophosphate and accelerated orotic acid decarboxylation in a mouse cell line resistant to purine and pyrimidine ribonucleosides.

A line of mouse fibroblasts (A9AU-1), originally selected for growth in the presence of 6-azauridine, has been found to be resistant to cytotoxic concentrations of adenosine, guanosine, and thymidine. A9AU-1 cells convert orotic acid to uridine 5'-monophosphate at twice the rate of the A9P line from which the A9AU-1 clone was selected. The resistant cells also excrete purines, synthesized de novo, into the medium at an increased velocity. The average intracellular 5-phosphoribosyl-1-pyrophosphate (PRPP) concentration of the resistant line is 45% higher than that of the parental line. The elevated PRPP concentration is likely to be responsible for both the apparent acceleration of pyrimidine synthesis and the increased excretion of purines into the growth medium; it might also account, by one of the several possible mechanisms, for the resistance of the cells to cytotoxic concentrations of the various nucleosides.

Adenine Phosphoribosyltransferase↗
PubMed1977

Suppression of production of mouse 28S ribosomal RNA in mouse-human hybrids segregating mouse chromosomes.

Mouse-human somatic cell hybrids that lose (segregate) human chromosomes produce only mouse 28S ribosomal RNA even when they retain copies of the human chromosomes that contain the genes for 28S ribosomal RNA. In contrast, mouse-human hybrid cells that segregate mouse chromosomes produce only human 28S ribosomal RNA even when they have retained copies of mouse chromosomes that contain the 28S ribosomal RNA genes.

Animals↗
PubMed1977

Analysis of human Y-chromosome-specific reiterated DNA in chromosome variants.

A number of individuals with aberrant Y chromosomes have been tested for the presence of Y-chromosome-specific reiterated DNA. These studies locate Y-chromosome-specific reiterated sequences on the long arm of the Y chromosome. Correlation with phenotype and other known Y chromosome markers establish that the Y-chromosome-specific reiterated DNA discussed here has no evident role in male determination.

Base Sequence↗
PubMed1977

Ag-staining of nucleolus organizer regions of chromosomes after A-,C-, G-, or R-banding procedures.

Metaphase chromosome preparations were made from leukocyte cultures of normal individuals. The cells were fixed in methanol:acetic acid (3:1 v/v), then dropped on cold, wet slides which were air-dried before storage at 4 degrees C. The slides were stained to identify the chromosomes by one of the following procedures: (1) Quinacrine. Slides were stained for 10 min in quinacrine mustard solution, rinsed in running tap water for 2 min, and mounted in Tris-maleat buffer, pH 5.6.

Animals↗
PubMed1977

Banded chromosomes of the owl monkey, Aotus trivirgatus.

Chromosomes of the owl monkey, Aotus trivirgatus, with 2n=54, 53, or 52, have been stained to show quinacrine (Q-) and Giemsa (G-) bands, and a karyotypic arrangement has been proposed based on lengths, centrometric index, and banding pattern. C-bands were present at the centromeric region of every chromosome and over the entire short arm of certain acrocentric chromosomes; 5-methylcytosine was concentrated in the same regions. Bright Q-bands at the telomeric ends of the short arms of some chromosomes probably represent a second type of repetitive DNA. Ag-staining showed that only the chromosomes bearing a secondary constriction are nucleolus organizer chromosomes.

Animals↗
PubMed1977

Chromosome analysis and alkaline phosphatase of C41, a cell line of human cervical origin distinct from HeLa.

The C41 cell line, which was derived from a human squamous carcinoma of the uterine cervix, has been characterized by analysis of quinacrine-banded metaphase chromosomes and study of alkaline phosphatase. C41 cells have a distinctive karyotype. They are hypodiploid, with a highly characteristic series of marker chromosomes, most of them derived by translocation or deletion. They contain no HeLa cell marker chromosomes, and the cell line shows no evidence of HeLa cell contamination. Nevertheless, the C41 and the HeLa cell line, both derived from cervix cancer, although of a different histological type, produce similar alkaline phosphatases. The enzyme is heat stable (placental type), is inhibited by L-phenylalanine, and responds to the inducing effects of prednisolone and/or hyperosmolality.

Alkaline Phosphatase↗
PubMed1977

Nucleolus organizers in Mus musculus subspecies and in the RAG mouse cell line.

Silver staining has been used to detect active nucleolus organizer regions (NOR's). By this criterion six mouse chromosomes, numbers 12, 15, 16, 17, 18 and 19, can have an NOR. The number and distribution of chromosomes with NOR's vary among inbred strains of Mus musculus musculus (C57BL/6J, BALB/cJ, C3H/HeJ and C3H/StCpr1BR) and in M. musculus molossinus. In a musculus X molassinus F1 hybrid, nucleolus organizers from each parent are silver stained.--Chromosomes which have NOR's in diploid cells also show them in tetraploid cells and in established cell lines. The BALB/cJ strain shows Ag-staining of NOR's on chromosomes 12, 15, 18 and occasionally 16. In the RAG cell line, which was derived from BALB/c, active NOR's are seen on 12, 15 and 18, even after these chromosomes have undergone structural rearrangements in the cell line. Some correlation exists between the amount of Ag-stain and the size of a secondary construction region, with a large amount of Ag-stain present on a chromosome which has a prominent secondary constriction. There is no correlation between the amount of Ag-stain and the presence or absence of C-band material.

Animals↗
PubMed1977

Frequency of satellite association of human chromosomes is correlated with amount of Ag-staining of the nucleolus organizer region.

Methaphase chromosomes from karyotypically normal adult humans (three males, six females) and one male with a 13p - chromosome were stained by quinacrine and then by the Ag-AS silver staining method to reveal nucleolus organizer regions (NORs). Each person had a characteristic number of Ag-stained chromosomes per cell, always fewer than 10. Determination of the mean Ag-size of each chromosome showed that each of the 10 individuals had a unique distribution of Ag-stain. Within each individual, there was some variation from cell to cell in the number of acrocentric chromosomes that were Ag-stained; this was not random, and the same chromosomes (those that had at most a small amount of Ag-stain) tended to be unstained in every cell. Satellite associations were scored on the same cells. Chromosomes that had no Ag-stain were involved in satellite association less than 20% as often as those that had some Ag-stain. Chromosomes that had a small amount of Ag-stain were involved in association about 50% as often as those that had a large amount of stain. Regression analysis of the 50 (of a total of 100) acrocentric chromosomes which could be individually identified by quinacrine markers showed that the frequency with which a chromosome was involved in satellite association was strongly correlated with the amount of Ag-stained material in the NOR.

Cell Nucleolus↗