Regulation of rRNA gene expression in a human familial 14p+ marker chromosome.
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Biomedical subjects
Publications and source records attributed to D A Miller.
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In the KOP translocation, t(X;14)(q13;q32), virtually the entire long arm of the X has been translocated to the end of the long arm of chromosome 14. Meiotic secondary nondisjunction in a female balanced carrier of the translocation has led to a son with two der(14) or 14-X chromosomes. The normal X chromosome is late replicating in the mother. One of the two 14-X chromosomes is late replicating in the son, with heavy terminal labeling of all but the centromeric end of the chromosome. This suggests that genetic inactivation has spread from the Xq segment of the translocation chromosome to at least two thirds of the segment derived from chromosome 14, and that the remaining proximal segment of chromosome 14 is possibly still genetically active. These findings provide an explanation for the phenotype: Klinefelter syndrome plus a few mild malformations that are sometimes seen in this syndrome but are also seen in duplication of the proximal portion of chromosome 14. Although the proband has a duplication of virtually an entire chromosome 14, 14(pter leads to q32), the phenotypic effect of the autosomal duplication has been mostly nullified by the spread of inactivation.
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Aotus monkeys, which are generally killed when infected with the human malaria parasite Plasmodium falciparum, have been identified and grouped by karyotype. These animals were immunized with parasite material obtained from P. falciparum cultivated in vitro which had been maintained in culture for over a year. When sufficient amounts of this antigenic material were used with a synthetic muramyl dipeptide (MDP), protective immunity was induced without presenting the antigen in complete Freund's adjuvant.
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.
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.
Human and higher primate chromosomes have been compared by general and regional banding methods, including hybridization in situ. The general banding patterns of the chromosomes of gorilla, chimpanzee, and orangutan, but not gibbon, are similar to those of the human. Preliminary results show that chromosomes with similar banding patterns in different species often carry the same genes. Repetitious DNA's have undergone changes in structure and distribution which are reflected in changes in the regional banding patterns. These studies confirm that the evolutionary distance between the gibbon and the orangutan is relatively great compared to the distance between the orangutan and the other great apes, and suggest that man is more closely related to the gorilla than to the chimpanzee.
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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.
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.
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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.
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.
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.
Joint crepitation after chamber air dives to 188 fsw. Undersea Biomed. Res. 4(1):89-94.-Joint crepitation was observed in all subjects (8) who were decompressed from 188 fsw (gauge) dry chamber air dives with a bottom time of 45 min. Crepitation was elicited by bending a joint as far as comfortably possible, and intensity of the sound was rated on a scale of 0 to +4. Fingers, wrists, and shoulders of both arms were examined immediately postdive, 1-4, 6- 10, and 20-24 hours postdive. Typically, the intensity and/or the number of joints affected increased during the 1-4 hour postdive period and then disappeared over the next 6-24 hours. The typical "squishy" sound heard in these joints may be due to bubble formation, although radiographic evidence was inconclusive. Closer examination for crepitance in future dives and the reporting of its occurrence may help to elucidate the mechanisms responsible for these joint sounds.
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