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Biomedical subjects

E Blanc

Publications and source records attributed to E Blanc.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Real space refinement of acto-myosin structures from sectioned muscle.

We have adapted a real space refinement protocol originally developed for high-resolution crystallographic analysis for use in fitting atomic models of actin filaments and myosin subfragment 1 (S1) to 3-D images of thin-sectioned, plastic-embedded whole muscle. The rationale for this effort is to obtain a refinement protocol that will optimize the fit of the model to the density obtained by electron microscopy and correct for poor geometry introduced during the manual fitting of a high-resolution atomic model into a lower resolution 3-D image. The starting atomic model consisted of a rigor acto-S1 model obtained by X-ray crystallography and helical reconstruction of electron micrographs. This model was rebuilt to fit 3-D images of rigor insect flight muscle at a resolution of 7 nm obtained by electron tomography and image averaging. Our highly constrained real space refinement resulted in modest improvements in the agreement of model and reconstruction but reduced the number of conflicting atomic contacts by 70% without loss of fit to the 3-D density. The methodology seems to be well suited to the derivation of stereochemically reasonable atomic models that are consistent with experimentally determined 3-D reconstructions computed from electron micrographs.

Actins↗
PubMedDate not supplied

[Ultrasound and CT study of duodenal pathology].

The radiological evaluation of the duodenum has traditionally been based on barium transit studies; however, ultrasound (US) and computed tomography (CT) are becoming more important in the assessment of this portion of the intestine and the structures that surround it. This report describes and illustrates the CT and US findings for different entities that affect the duodenum, including diseases of the duodenum itself and those of neighboring organs that affect this portion of the small intestine. We classify the pathologies by etiology into congenital, traumatic, iatrogenic and foreign bodies, bezoars, hematologic, inflammatory and neoplastic. Moreover, we present the incidental duodenal and periduodenal findings in US and CT that radiologists should be familiar with given the widespread use of these techniques.

Duodenal Diseases↗
PubMedDate not supplied

[Endo-surgical dissection of the upper urinary tract through the retroperitoneal and transperitoneal route: an experimental study with pigs and cadavers].

In order to define the best method for endosurgical dissection of the upper urinary tract, an experimental study comparing the retroperitoneal and transperitoneal approaches was performed. Between September 1991 and February 1992, 15 female pigs and 8 human cadavres underwent endosurgical dissection of the upper urinary tract. The retroperitoneal approach was used in 8 pigs and 5 cadavres. In the lateral supine position, the retroperitoneum was insufflated at the lower pole of the kidney, via a 2 cm cutaneo-muscular incision, followed by a blind dissection with the finger to create a space in the retroperitoneal fat. Four trocars were inserted into the retroperitoneal space allowing dissection of the ureter, kidney and its vascular pedicle. The renal vessels and the ureter were then clipped or stapled with the endo-GIA then sectioned. The operation was successfully performed in all of the pigs with a mean operating time of 2 hours. Complications were limited to two peritoneal effractions. Retroperitoneal endosurgical dissection was much longer and more difficult to perform on the cadavre (mean operating time: 3 hours). Satisfactory retropneumoperitoneum was never able to be obtained due to the large amount of retroperitoneal fat and the proximity of the twelfth rib and posterior iliac crest interfered with the insertion of the trocars and made dissection more difficult. The transperitoneal approach was performed in 7 pigs and three cadavres. In the lateral supine position, after creating pneumoperitoneum using a Veress needle, 4 trocars were inserted into the peritoneal cavity. Toldt's fascia was gripped and incised allowing retraction of the colon towards the midline, thereby exposing the renal region. The ureter and the renal vessels were dissected. The renal artery and vein were then clipped or stapled with the endo-GIA then sectioned, while the ureter was clipped and sectioned. The complications of the transperitoneal route were: an injury to the small intestine during insertion of a trocar and haemorrhage due to accidental section of a lower pole renal artery, which was able to be controlled by application of clips. In the pig, the transperitoneal approach was as simple to perform as the retroperitoneal approach and the mean operating time was the same (two hours).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗