Biomedical subjects

A Gratias

Publications and source records attributed to A Gratias.

3 recordsLinked to original sources

PubMed1994

[Modern imaging of atheromatous aneurysms of the abdominal aorta].

Radiologic imaging advances, during the last decade, deeply modified diagnosis, follow up and preoperative staging of aortic abdominal atheromatous aneurysms. When congenital, infectious and inflammatory aneurysms are rare, atheroma is the most frequent etiology of aneurysms. Ultrasonography is actually very reliable for aneurysms diagnosis. Inexpensive, it is the best exam for early screening in a risk population (arterial hypertension). If ultrasonography is adequate for diagnosis and follow up, two tests are necessary for pretherapeutic staging: arteriography and computed tomography (CT). CT is more accurate than ultrasonography. It is realized just after arteriography without any other contrast media injection. Angiography of aorta and limbs vessels shows the whole arterial system and allows the adaptation of surgical procedure. IRM is more expansive and less accessible, it has not proved it superiority versus CT. It is realized only when CT is unwise (allergy, renal failure). Helicoidal CT will be in the future the best exam to study the whole vascular system and will probably take the place of arteriography and CT.

Aortic Aneurysm, Abdominal↗

PubMedDate not supplied

Developmentally programmed excision of internal DNA sequences in Paramecium aurelia.

The development of a new somatic nucleus (macronucleus) during sexual reproduction of the ciliate Paramecium aurelia involves reproducible chromosomal rearrangements that affect the entire germline genome. Macronuclear development can be induced experimentally, which makes P. aurelia an attractive model for the study of the mechanism and the regulation of DNA rearrangements. Two major types of rearrangements have been identified: the fragmentation of the germline chromosomes, followed by the formation of the new macronuclear chromosome ends in association with imprecise DNA elimination, and the precise excision of internal eliminated sequences (IESs). All IESs identified so far are short, A/T rich and non-coding elements. They are flanked by a direct repeat of a 5'-TA-3' dinucleotide, a single copy of which remains at the macronuclear junction after excision. The number of these single-copy sequences has been estimated to be around 60,000 per haploid genome. This review focuses on the current knowledge about the genetic and epigenetic determinants of IES elimination in P. aurelia, the analysis of excision products, and the tightly regulated timing of excision throughout macronuclear development. Several models for the molecular mechanism of IES excision will be discussed in relation to those proposed for DNA elimination in other ciliates.

Animals↗

PubMedDate not supplied

[Perception errors in detecting advanced colorectal cancers using a double-contrast enema].

The authors provide a didactic analysis of the errors in perception that can lead to false-negative findings in the detection of advanced rectocolonic cancers with double-contrast enema. They consider 5 categories of images as typical, ie. transverse or horizontal linear opacities, abnormal lumen due to haustral folds on semiaxial views, "pool sign", amputation of the cecum and irregular hypertrophy of the ileocolic valve. These mistakes will become exceptional if the double-contrast images are studied thoroughly using precise rules, and the percentage of false-negative findings in the detection of rectocolonic cancers should thus be reduced to 1%.

Aged↗