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D Rawlins

Publications and source records attributed to D Rawlins.

8 recordsLinked to original sources
PubMed2001

Ancient chronology. Astronomical orientation of the pyramids.

Spence speculates that Egypt's pyramid builders found true north by using a plumb line: when the stars Kochab and Mizar were seen on the same vertical, one was facing north. As evidence in support of this hypothesis, she points to the proposed interstar-line precession past the north celestial pole at a rate of 27' per century (cy). We argue that a mathematical error affects this result, which when corrected points more strongly to a different pair of stars. This suggests that the conventional ancient chronology, instead of being compressed, may actually have to be expanded slightly.

Journal Article↗
PubMed1991

Microtubules rich in post-translationally modified alpha-tubulin form distinct arrays in frog lens epithelial cells.

Isolated frog lens epithelia were stained with antibodies against tyrosinated, detyrosinated or acetylated alpha-tubulin and observed by several means including a scanning confocal microscope. The most prominent feature of Rana pipiens lens cells was a primary cilium close to the apical surface of the cells above the centrosome. This structure was associated with microtubules rich in modified alpha-tubulin. The cilium was less pronounced but still discernible in the cells of another species R. ridibunda. In both species, the modified (acetylated or detyrosinated) microtubules formed arrays spatially distinct from the unmodified (tyrosinated) microtubules. The modified microtubules formed a basket of microtubules with a curly distribution around the nucleus while the tyrosinated array consisted predominantly of rather straighter microtubules running from the apical centrosome to the cell periphery, down the lateral sides of the cells and across the basal surface adjacent to the lens capsule and basement membrane. It is concluded that the organization of modified microtubules previously described for several types of cultured cells may represent a remnant of the three-dimensional perinuclear array of such microtubules described here for the cells of an intact epithelium.

Animals↗
PubMed1986

The metabolic effects of thiazide therapy in the elderly: a population study.

The metabolic consequences of thiazide diuretics are well known. The elderly to whom these agents are widely prescribed may be particularly susceptible. To quantify this metabolic risk, plasma and intracellular electrolytes and plasma glucose were measured in the elderly population of a Somerset village. Highly significant reductions in both plasma and cellular magnesium and potassium were found in the 47 thiazide-treated people. Forty-eight per cent of the thiazide-treated group were hypomagnesaemic and 28% were hypokalaemic. Thus, magnesium and potassium depletion are commonly associated with thiazide therapy in the elderly. These metabolic effects should be considered carefully prior to the use of these agents.

Aged↗
PubMedDate not supplied

High-affinity binding site for a specific nuclear protein in the human IgM gene.

Proteins binding to specific regions of DNA with high affinity frequently govern or regulate reactions at the gene level. We have identified a high-affinity binding site in the immunoglobulin mu gene that binds a specific nuclear protein, and have now characterized it fully using nuclear factor 1 (NF-1), a protein purified from the nuclei of HeLa cells and required for the in vitro replication of adenovirus (Ad) DNA. NF-1 protects a 25-base pair (bp) double-stranded segment of DNA which shares a consensus sequence, 5' TGGA/CNNNNNGCCAA 3', with similar binding sites in the Ad-5 terminal repeat and the human c-myc gene. Although this site differs from the enhancer region, a biological function is suggested by the fact that it is DNase I hypersensitive in immunoglobulin-producing lymphoblastoid cells. The binding site for the NF-1 protein in the mu gene, by analogy with the site in the Ad-5 terminal repeat, may represent one component of a cellular origin of replication; alternatively, it may be responsible for the activation of the chromatin in this region.

Base Sequence↗