Biomedical subjects

J Attia

Publications and source records attributed to J Attia.

23 records · Page 2Linked to original sources

PubMed1989

[Anesthesia and bone marrow harvesting in children].

Allogeneic bone marrow transplantation is increasingly used to treat a great variety of disorders which range from genetic conditions to leukaemia. Most often, the donor is a healthy sibling of the patient. Bone marrow harvesting in young children is a very painful procedure requiring anaesthesia; this presents yet more risk for the donor. In order to analyse the specific problems related to this procedure, a retrospective study was carried out on 30 anaesthetic records of marrow-harvesting procedures performed between January 1980 and December 1987. The 30 harvests were carried out in 28 patients (15 boys, 13 girls). Mean age of donors was 6 +/- 0.8 yr (range: 13 months to 17 yr). Twenty-seven patients were classed ASA I and one ASA II. The harvests were all carried out in prone and intubated patients. The volume of removed marrow was 350 +/- 80 ml (range 170 to 600 ml). This was equivalent to a mean 21% estimated blood volume (6-37%). Blood transfusion with phenotyped irradiated blood was carried out in 18 patients, and with autologous blood in one. Mean duration of the procedure was 88 +/- 6 min and the mean stay in hospital was three days. The potential risks for the children are discussed, as well as the related legal problems.

Adolescent↗

PubMed1989

Modulated adhesion: a proposal for the role of myelin-associated glycoprotein in myelin wrapping.

Myelin-associated glycoprotein (MAG) is a 100-kDa integral membrane glycoprotein expressed by oligodendrocytes and Schwann cells in the central and peripheral nervous systems, respectively. It is found first in loosely wrapped myelin and then periaxonally after compaction. Clinical findings, structural analysis, and cell assays indicate a role for MAG in adhesion. We propose that the phosphorylation state of MAG modulates its adhesion and that a minimum spatial requirement for the separation of the kinase and phosphatase activities postulated by this model may explain the correlation between axon size and myelination state.

Cell Adhesion↗

PubMed1987

Studies of adenosine incorporation in Langendorff rat heart and rat heart mitochondria.

The acid-insoluble product isolated from well-oxygenated Langendorff rat heart after perfusion with [14C]adenosine was purified by phenol extraction and subjected to specific phosphorolysis by pure polynucleotide phosphorylase. TLC analysis of the reaction mixture showed that ADP was the only radioactive product, proving that the original substance was a polyribonucleotide. Studies of the time course of labelling and of the distribution of the acid-insoluble product between the mitochondrial and nuclear fractions showed that both are labelled even after 1 min at 25 degrees C, but at short times and low temperature more radioactivity is found in the mitochondria. The kinetics of adenosine incorporation resemble those expected for the labelling of hnRNA and mRNA. Isolated, respiring mitochondria incorporate adenosine and adenine nucleotides into acid insoluble form by a process dependent on oxidative phosphorylation and the adenine nucleotide translocase that is specific for adenine derivatives. The results are discussed in terms of the hypothesis that the polyribonucleotide might be a storage form of adenine nucleotides: it is concluded that the bulk of the labelled product is unlikely to play a major role in energy metabolism.

Adenine Nucleotides↗

PubMed1986

Epidural morphine in children: pharmacokinetics and CO2 sensitivity.

The effects of epidural morphine (50 micrograms X kg-1) after abdominal and urologic surgery were studied in 20 children ranging in age from 2 to 15 yr and weighing between 9 and 54 kg. The onset and the duration of analgesia were 30 +/- 12 min and 19.5 +/- 8 h, respectively (mean +/- SD). Side effects were pruritus (4/20), nausea and vomiting (8/20), and urinary retention (4/14). No apnea was observed. Ventilation control was studied in seven children. No significant change in resting respiratory variables occurred after both surgery and epidural morphine injection. However, the slope of the ventilatory response to CO2 was significantly (P less than 0.05) decreased after surgery but before morphine, as compared with its preoperative control value (0.84 +/- 0.44 versus 1.51 +/- 0.72 l X min-1 X mmHg-1), and remained low for 22 h after epidural morphine (0.90 +/- 0.57 l X min-1 X mmHg-1). Sixty minutes after morphine injection, the plasma morphine concentration was always less than 12 ng X ml-1 in the seven children studied. Pharmacokinetic parameters were similar to those observed after epidural injection of morphine in adults, except for a shorter terminal half-life (73.8 +/- 41.6 min) attributed to a greater total body clearance of morphine in the children (28.3 +/- 3.4 ml X min-1 X kg-1). It is concluded that epidural morphine provides effective and prolonged analgesia in children after abdominal and urologic surgery and that it is associated with prolonged respiratory depression that requires close monitoring for at least 24 h.

Adolescent↗

PubMedDate not supplied

A graphic framework for teaching critical appraisal of randomized controlled trials.

Students of evidence-based medicine often try unsuccessfully to commit to memory a particular critical appraisal framework (often lengthy), or they have to depend on pocket cards and are lost without them. We have described a pedagogic aid: a flow diagram of an RCT, which has been developed over years of teaching residents. This diagram focuses on the steps in an RCT, and by drawing arrows, it highlights the biases possible at each step. This diagram serves as a framework on which the list of critical appraisal questions can be hung and is easy to remember.

Audiovisual Aids↗