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Biomedical subjects

A Barthélémy

Publications and source records attributed to A Barthélémy.

12 recordsLinked to original sources
PubMed2006

Co-doped (La, Sr)TiO(3-delta) : a high Curie temperature diluted magnetic system with large spin polarization.

We report on tunneling magnetoresistance (TMR) experiments that demonstrate the existence of a significant spin polarization in Co-doped (La, Sr)TiO(3-delta) (Co-LSTO), a ferromagnetic diluted magnetic oxide system (DMOS) with high Curie temperature. These TMR experiments have been performed on magnetic tunnel junctions associating Co-LSTO and Co electrodes. Extensive structural analysis of Co-LSTO combining high-resolution transmission electron microscopy and Auger electron spectroscopy excluded the presence of Co clusters in the Co-LSTO layer and thus, the measured ferromagnetism and high spin polarization are intrinsic properties of this DMOS. Our results argue for the DMOS approach with complex oxide materials in spintronics.

Journal Article↗
PubMed2005

Spin-polarized tunneling spectroscopy in tunnel junctions with half-metallic electrodes.

We have studied the magnetoresistance (TMR) of tunnel junctions with electrodes of La(2/3)Sr(1/3)MnO3 and we show how the variation of the conductance and TMR with the bias voltage can be exploited to obtain precise information on the spin and energy dependence of the density of states. Our analysis leads to a quantitative description of the band structure of La(2/3)Sr(1/3)MnO3 including the energy gap delta between the Fermi level and the bottom of the t(2g) minority-spin band, in good agreement with data from spin-polarized inverse photoemission experiments. This shows the potential of magnetic tunnel junctions with half-metallic electrodes for spin-resolved spectroscopic studies.

Journal Article↗
PubMed1999

[Severe air embolism after surgical irrigation with hydrogen peroxide].

BACKGROUND: Hydrogen peroxide is widely used for its antiseptic properties. In certain circumstances, however the risk of air embolism can create a life-threatening situation. CASE REPORT: A 16-year-old adolescent required surgical treatment for femorotibial trauma. During the surgical procedure, cardiac arrest suddenly occurred when hydrogen peroxide was being used to irrigate the wound. A central catheter was inserted and aspiration of air bubbles in the line led to the diagnosis of air embolism. Outcome was unfavorable despite successful resuscitation. A chronic neurovegatative state ensued and the patient died 8 months later. DISCUSSION: Several cases of air embolism have been described due to hydrogen peroxide in surgical, medical and accidental circumstances. Our case emphasizes the potential danger of using hydrogen peroxide in certain situations, including orthopedic surgery. Clinicians should be aware that hydrogen peroxide is not a perfectly safe product.

Adolescent↗
PubMed1992

[Non-malignant esophagotracheal fistulas in adults. Experience with 35 cases].

Esophagotracheal fistula always constitutes a serious, life-threatening complication. Fistulae occurring during medical intensive care with mechanical ventilation are currently the most frequent. Their diagnosis was strongly suspected by clinical examination of the patient, but was always confirmed by endoscopy which revealed their exact site in relation to the vocal cords or carina, essential information for the choice of incision when it is decided to perform surgery. Twenty-five patients were treated medically. Treatment was always combined with gastrointestinal resting, control of gastro-oesophageal reflux and broad-spectrum systemic antibiotics. There were 19 deaths and 6 fistulae closed spontaneously. Three of these 6 patients developed a secondary tracheal stenosis, 2 of which were treated surgically by resection-anastomosis. Ten fistulae were closed surgically with a good long-term result. The indication for surgery was essentially based on the patients general and infectious status and on his or her respiratory autonomy. Technically, we always combined direct suture of the two organs with interposition of muscular or pleural tissue.

Adult↗
PubMed1992

[Gangrene of the perineum. Plea for a standardized therapeutic management apropos of 50 cases].

From 1988 to 1992, 50 cases of perineal gangrene were treated with a therapeutic protocol combining: a) repeated extensive excisions, b) hyperbaric oxygen therapy, even before surgery if this was possible, and c) intensive care. The mortality rate was 24% (12/50). It was even higher in patients admitted more than 6 hours after diagnosis. The average stay in hospital was of 20 (+/- 2) days. Four patients presented with residual signs. Twenty-eight (56%) had had colostomy for lesions originating in the rectum or threatening the anal margin; 9 of these patients died, while gastrointestinal continuity was restored in another 17 cases. There were three predictive factors of survival in this series: a) early diagnosis and treatment, b) severity index on admission, c) some associations of bacteria.

Adult↗
PubMed1985

[Open heart cardiac surgery in severe renal insufficiency and dialysis patients].

Surgically remediable cardiovascular complications are common in patients with renal failure treated by dialysis. 20 such patients were operated in our department (16 men and 4 women), aged 27 to 61 years (mean 44.5 years). 12 patients had undergone haemodialysis for 1 to 84 months; 4 patients were treated by peritoneal dialysis; the remaining four patients all had severe renal failure with creatinine clearances of less than 10 ml per minute. All patients were operated immediately after a session of dialysis. Particular attention was paid to preserving the peripheral arterial and venous vessels during anaesthesia and cardiopulmonary bypass. The jugular veins were used whenever possible to spare the upper limb veins and the dorsalis pedis arteries were used for the monitoring of systemic blood pressure to spare the radial arteries for eventual arteriovenous fistulae. Weight gain during the operation was limited by cardiopulmonary bypass techniques. The circuit was filled with 200 cc of B 21, 500 cc of isotonic bicarbonate solution and 800 cc of frozen plasma with potassium supplements. Mean weight gain was moderate (1.1 +/- 0.4 kg). 12 patients underwent valve replacement. The surgical indication was acute endocarditis in 6 cases. The aortic valve was replaced in 10 cases and the mitral valve in 2 cases by mechanical valve prostheses because of the high risk of calcification of bioprostheses in severe renal failure. 8 patients underwent coronary bypass graft surgery. Arterial blood pressure was maintained at over 60 mmHg and large doses of heparin were used to protect the arteriovenous shunts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1980

[Pes anserinus transfer and medial transplantation of the tibial tubercle in the treatment of rotary instability of the knee (author's transl)].

23 cases of rotary instability of the knee have been reviewed with an average follow up of 5 years. They have been treated by a combination of pes anserinus transfer using Slocum's technique with medial transposition of the tibial tubercle. Functionally the results were satisfactory and there was no antero-posterior instability. No secondary patello-femoral arthrosis was seen. All the knees seemed to be more stable but most cases showed some degree of effusion, quadriceps wasting and some pain. It is concluded that this type of surgical procedure may provide a satisfactory knee for lighter sporting activities but not for competitive sport.

Adolescent↗
PubMedDate not supplied

[Progressive bone lengthening using Wagner's technique (author's transl)].

The authors have reviewed the results of 30 surgical procedures of progressive bone lengthening using the Wagner's technique. In 28 cases, internal fixation was applied at the end of the lengthening period. There were 17 femora and 13 tibae operated on. In 6 cases, lengthening was associated with a correction of the alignment of the femur, and in 2 cases was associated with the treatment of a non-union of the tibia. Complications are described; they were found to be relatively rare.

Adolescent↗