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Biomedical subjects

T E Denton

Publications and source records attributed to T E Denton.

16 recordsLinked to original sources
PubMed1992

The use of instant moiré photographs to reduce exposure from scoliosis radiographs.

A total of 258 patients with some degree of idiopathic scoliosis was monitored with both radiographs and moiré photography to determine the degree of progression of spinal curvature. The use of polaroid photography to document moiré fringe patterns proved to be a rapid and useful process for placing an instant photographic record in patient charts while conducting routine physical examinations. Standardization of procedures for making and evaluating moiré photographs reduced patient exposure to X-rays.

Adolescent↗
PubMed1981

The relationship between aging and ribosomal gene activity in humans as evidenced by silver staining.

Silver selectively stains nucleolar organizer regions (NORs) distributed on the D and G chromosomes of man. The number of NORs is fairly constant for a given individual but is highly variable within populations. When 2540 metaphases from lymphocytes were examined from 127 normal subjects, a mean NOR number of 7.3 was obtained with a mode of 7. No significant difference was found in mean NOR number between females and males. However, regression lines do show a decrease in NOR number with aging for both sexes but the rate of decline is more evident in females. Also, G chromosome NORs appear more stable than those in D chromosomes. Since silver--NOR staining is indicative of ribosomal gene activity, it is proposed that lymphocyte rDNA becomes less sensitive to phytohemagglutinin stimulation during aging. It is unique that this gene repression can be visualized with conventional staining and light microscopy.

Adolescent↗
PubMed1981

Variation in nucleolar organizer activity in lymphocytes of females with adenocarcinoma.

With the use of Ag staining and conventional light microscopy, a difference is visualized in the frequency of nucleolar organizer regions between PHA-stimulated lymphocytes from normal females and females with various types of adenocarcinoma. This difference in NOR activity is more pronounced in G chromosome than D chromosomes. It is feasible that rDNA gene activity in PHA-stimulated lymphocytes is augmented in patients with adenocarcinoma due to the presence of plasma mediators arising from cellular malignancies. The NOR regions located on G chromosomes are considered to be more sensitive to these mediators than those on D chromosomes.

Adenocarcinoma↗
PubMed1977

Distribution patterns of satellite associations in human lymphocytes relative to age and sex.

Using ammoniacal silver for differential staining of satellites, associations from 1,668 human metaphases were studied from lymphocyte cultures of 167 normal individuals and were correlated with age and sex. There is a peak in satellite association frequency up to age 20 years in males and to 25 in females. With older ages there is a decline in association frequencies. No associations with four or more chromosomes were found in newborns. Furthermore, association in newborns, as well as in individuals older than 50 years, are significantly low compared to in-between age groups. Females have a higher frequency of satellite associations than males between the ages of 3 and 50 years. Typically, females have greater multiple associations, while males have more single associations. Randomness or non-randomness of occurrence of associations fluctuates for different age groups within and between the two sexes.

Adolescent↗
PubMed1976

Negative silver staining in A-T and satellite DNA-rich regions of human chromosomes.

Human metaphase chromosomes were stained with silver following a pretreatment with a heated alkaline solution. The most conspicuous feature of the stained metaphases was the omission of silver staining in the secondary constrictions of chromosomes 1,9 and 16, and on the distal Yq. Our evidence indicates that the negative silver binding is due to the preferential removal or alteration of non-histone proteins associated with these regions. The cytochemical significance of these findings is discussed.

Adenine Nucleotides↗
PubMed1976

Human nucleolar organizer chromosomes: satellite associations.

The D and G group chromosomes from cultured human lymphocytes exhibit single and multiple satellite associations when stained with silver. Unlike earlier methods this simple and highly repeatable procedure shows physical attachments between satellited regions of various acrocentric autosomes. After studying 1,000 satellite associations from 118 normal individuals, it was found that both single and multiple associations occur with frequencies that correlate with random expectancies.

Cell Nucleolus↗
PubMed1976

Inclusion of satellites in an 18/21 translocation chromosome shown by ammonical-silver staining (sat-banding) in case of partial trisomy 18.

A male infant with a partial trisomy 18 and a 46,XY, --21, t(18;21)(18qter replaced by 18q12::21 p13 replaced by 21 qter) chromosome complement is described. The translocation chromosome is of special interest because it includes the satellites of chromosome 21. This was shown by differential satellite staining with the ammoniacal-silver technique.

Ammonia↗
PubMed1974

Chromosomes of the chocolate gourami: a cytogenetic anomaly.

The chocolate gourami, Sphaerichthys osphromonoides, has the lowest chromosome number reported for fishes, with 2n = 16 and n = 8. Other members of the family Belontiidae have somatic numbers of 42 to 48. Chromosome instability is demonstrated by the presence of somatic abnormalities and meiotic multivalents.

Animals↗