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Biomedical subjects

M Lemieux

Publications and source records attributed to M Lemieux.

At least 37 records · Page 2Linked to original sources
PubMed1988

A new porcine bioprosthesis: design rationale and early clinical experience.

The Medtronic Intact valve is a third-generation porcine bioprosthesis produced using a leaflet fixation process which imposes virtually zero hydrostatic pressure. This fixation method provides optimal preservation of the original leaflet structure and integrity and should result in an improvement in durability compared to conventional preservation techniques. The biomechanical basis for this hypothesis is presented along with early experience with 118 patients (125 valves). There have been no complications related to primary valve failure and the incidence of other valve related events is acceptable.

Aortic Valve↗
PubMed1987

Compartmentation of glucose 6-phosphate in hepatocytes.

Rat hepatocytes were incubated with 14C-labelled hexoses, and the specific radioactivities of glucose 6-phosphate, glucose 1-phosphate and fructose 6-phosphate were determined. (1) When suspensions of freshly isolated hepatocytes were incubated with [14C]glucose, the specific radioactivities of glucose 1-phosphate and fructose 6-phosphate were severalfold higher than that of glucose 6-phosphate. The ratios of the specific radioactivities decreased with time of incubation. These relationships were also found when incubations were carried out with primary cultures of rat hepatocytes or with crude homogenates of hepatocytes, but not with isolated nuclei. (2) When cells were incubated with [14C]fructose, the ratios of the specific radioactivities were higher than with [14C]glucose, and also decreased with time. (3) Paired incubations were carried out with a mixture of galactose and fructose, with one or other sugar being labelled with 14C. The specific radioactivity of glucose released into the medium was greater than that of glucose 6-phosphate when fructose was labelled, but not when galactose was labelled. Furthermore, glucose 6-phosphate and glucose in the medium differed with regard to the distribution of 14C between C-1 and C-6. These results are interpreted as evidence that glucose 6-phosphate in hepatocytes does not exist as a homogeneous pool, but that subcompartments exist which are associated with glucose phosphorylation, gluconeogenesis and glycogenolysis.

Animals↗
PubMed1985

Concentrations of fusidic acid, cloxacillin, and cefamandole in sera and atrial appendages of patients undergoing cardiac surgery.

The concentrations of cefamandole, cloxacillin and fusicid acid were measured in the serum and heart tissue of 100 recipients of these drugs before cardiac surgery. During cardiopulmonary bypass, mean (+/- standard deviation) peak concentrations in serum of all patients were 63.0 +/- 34.0 micrograms of cefamandole per ml, 30.8 +/- 17.7 micrograms of cloxacillin per ml, and 32.4 +/- 10.8 micrograms of fusidic acid per ml. Mean (+/- standard deviation) concentrations in atrial appendages taken 1 h (+/- 15 min) after infusion were 21.3 +/- 11.0 micrograms of cefamandole per g, 23.8 +/- 17.3 micrograms of cloxacillin per g, and 10.7 +/- 4.2 micrograms of fusidic acid per g. No cloxacillin could be detected in 5 of 39 heart specimens. Mean tissue-to-serum ratios at 1 h for cefamandole, cloxacillin, and fusidic acid were respectively 0.35, 0.73, and 0.33. Fusidic acid, a drug which is highly effective in vitro against both methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, was detectable in heart tissue in concentrations which were 12 times higher than the MICs of this agent against these resistant microorganisms.

Adult↗
PubMed1980

Transaxillary pleurectomy for treatment of spontaneous pneumothorax.

In the 16-year period 1962 to 1978, 409 transaxillary apical pleurectomies were carried out for definitive treatment of spontaneous pneumothorax in 362 patients. Surgical indications included recurrence (336), bilaterality of the disease (23), persistent air leak (22), and nonexpansion of the lung (10). There was 1 operative death (unsuspected brain tumor), and 3 patients required reexploration for clot removal. The average postoperative period of hospitalization was 6 days. Three hundred ten patients (86% of all patients) were contacted for follow-up 1 to 16 years after operation (average, 4.5 years). There were two documented episodes of recurrent ipsilateral pneumothorax (0.6%). Postoperative pulmonary function studies were done in 40 patients (unilateral, 29; bilateral, 11) 2 to 5 years after operation. The results indicate that there are no significant abnormalities compared with predicted values.

Adolescent↗
PubMed1978

Value of a cinefluoroscopic assessment of the Lillehei-Kaster prosthetic heart valves.

In order to assess the functioning of the pivoting disc of the Lillehei-Kaster prosthetic valve, a cinefluoroscopic technique using multiple angulations was developed. The disc was detected in 240 (99%) of the 242 valves studied (126 aortic, 107 mitral, and nine tricuspid valves). The maximal-opening angle of the disc was measured in 75% of the aortic but only 20% of the mitral valve prostheses in the 182 valve studies in which this was attempted. Prosthetic dysfunctions were suspected clinically in three aortic and three tricuspid valves and confirmed with the cinefluoroscopic technique. This cinefluoroscopic approach constitutes a rapid, noninvasive, and sensitive evaluation of the function of the Lillehei-Kaster prosthetic valve in the aortic position.

Aortic Valve↗
PubMed1977

[Prevention and chronicity in community psychiatry.].

The author poses the problem of the chronic mental patient in 1977 in light of the commu-nity approach. During the 1950's the discovery of penicillin, the phenothiazines and the anti-depressants; the notion of institutional dementia as well as the rapid growth of physical health costs, formed the basis for a needed reform which took the guise of community psychiatry. The latter created many hopes (eg. the possible elimination of the asylum, the potential for preventive effects). In fact community mental health programs did produce a decrease in the hospitalized psychiatric population, a higher quality of hospital services, a change in the laws relating to the mentally ill, and an improvement in treatment, personnel competence as well as a stability in real health costs. But the 1970's brought disillusionment. The rate of psychotic disorder remains unchanged, the cost-benefit of the program is less than had been anticipated and, in addition, the community approach has transplanted the asylum to the city thus creating a new immigrant - the psychotic individual. Citing this failure, the author argues for a psychiatry focussed on research into the makeup of the internal psychotic dynamic and its treatment.

English Abstract↗
PubMed1976

Mediastinopleuroscopy: a new approach to the diagnosis of intrathoracic diseases.

With the advent of modern therapy, it has become essential to obtain a tissue diagnosis in all cases of pulmonary and mediastinal disease. Since it is often necessary to resort to thoracotomy as a final step in making such a diagnosis, we have sought a procedure that is simpler while capable of providing the same information. Through a standard cervical mediastinoscopy incision, the mediastinum is first explored; if the diagnosis is not obtained, the mediastinal pleura is digitally opened and lung or pleural biopsies are taken. In the course of 1,100 mediastinoscopies since 1969, 275 pleuroscopies have been done. We were able to obtain a tissue diagnosis in 102 (78%) of 131 patients with bronchogenic carcinoma, in 92 (91%) of 102 with benign pulmonary disease, and in all 20 (100%) with pleural disease.

Biopsy, Needle↗