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Biomedical subjects

M Pierrot

Publications and source records attributed to M Pierrot.

30 records · Page 2Linked to original sources
PubMed1982

Crystal structure and electron transfer properties of cytochrome c3.

The crystal structure of cytochrome c3 from the sulfate-reducing bacteria Desulfovibrio desulfuricans, Norway strain, has been determined through the fitting of the recently completed primary structure to a 2.5 A resolution electron density map. The phase calculations were based on three mercurial derivatives; anomalous scattering data were used to refine the four heme iron positions. A preliminary refinement of the molecular model has led to a conventional crystallographic R factor of 34%. Cytochrome c3 is folded in two structural domains with one heme in each, the two other heme moieties lying in a large groove dividing the molecule. The core of the protein is the compact four-heme cluster which presents a relatively high degree of solvent exposure. The structural pattern of redox centers suggests that electron transfer might occur through direct contacts between some of the heme groups, via the overlapping system of pi oribitals or via intervening amino acid side chains or both.

Cytochrome c Group↗
PubMed1982

Pancreatic colipase: crystallographic and biochemical aspects.

A detailed study of the crystallization of hog and horse colipases has been undertaken. Several crystallographic varieties have been obtained and a 0.3-nm resolution structure determination is actually in progress. The sequence of the A form of horse colipase (one methionine) is given. From spectrophotometric experiments and sequence comparisons, the involvement of the aromatic residue in position 52 in the micelle binding site has been demonstrated.

Amino Acid Sequence↗
PubMed1982

[Peridural analgesia with high doses of fentanyl: failure of the method for early postoperative kinesitherapy in knee surgery].

Following orthopedic surgery of the lower limb, ten patients were given fentanyl 5 micrograms . kg-1 in a single epidural injection. Almost complete analgesia (P less than 0.001) was rapidly obtained. The total period of analgesia was rather short (182.3 +/- 32.1 min). The maximal analgesia period was 87 +/- 8.34 minutes. Despite this high dose of fentanyl (245 to 450 micrograms), in five patients the passive mobilization of the knee following surgery was extremely painful and, for that matter, impossible in three of them. Such high doses of fentanyl entail the risk of respiratory depression as respiratory rate is decreased (P less than 0.01) and the Pco2 is increased (P less than 0.01). Fentanyl should not be used at such high dosage and should probably not be preferred to morphine, considering that the duration of analgesia is short, that the analgesic score is identical to that obtained with lower doses or with longer lasting narcotics, that it does not prevent passive mobilization pains and that it entails a definite risk of respiratory depression.

Adult↗
PubMed1981

[A technique for sampling uncontaminated peripheral bronchial secretions in patients wih intubation or tracheostomy (author's transl)].

Sixty patients were studied during non cardiac thoracic surgery. In 21,6 p. cent a culture of organism was isolated and for 53.8 p. cent of them developed a pneumonic process during postoperative period. The organism'role was confirmed by clinical correlation and an abnormal chent radiograph. The same organism was isolated in blood culture sputum or empyema. On the other side the patients with sterile cultures had always a favorable course. The results confirmed the interest of the method which would permit a prophylactic antibiotherapy.

Aged↗
PubMed1981

[Early acute pulmonary oedema happening during peritoneovenous by pass (author's transl)].

The authors report the cases of two cirrhotic patients without cardiac failure who underwent peritoneo-venous bypass (Leveen valve). On the two cases an acute pulmonary oedema (APE) serious but not fatal was noted at the 36e hour. This one was associated with a rise of cardiac output and a moderate rise of the pulmonary wedge pressure (15-18 mm Hg). The administration of thiamine did not correct these perturbations but small doses of furosemide corrected the APE. Despite the low frequency of the cases of APE after Leveen bypass and their mechanism not definitevely known, the authors recommend in pre-, per- and post-operative period the monitoring of cardiac function with a right catheterism.

Acute Disease↗
PubMed1981

[Acute pneumonia without pyosis among adults. Outcome of seventy-transtracheal aspirations (author's transl)].

Seventy transtracheal aspirates (T.T.A.) have been achieved with patients having an acute pneumonia; 42 had a chronic respiratory failure; 25 had received a previous antibiotherapy; 49 presented negatives delayed hypersensitivity skin reactions. No major accident was noticed and the T.T.A. were positive in 87 p. cent of the cases. The results show the predominance of the Cocci Gram + especially pneumococcus. These cases are associated with Hemophilus influenzae in 19 p. cent of the cases. Negative skin tests show the frequency of this association. Infections with Bacilles Gram -- are found as well in this circumstance. The previous antibiotherapy alters microflora and leads to a B.G. -- as well predominance. At last, the evolution is not influenced by the discovery of an organism in the T.T.A. The authors compare the results with those found in previous work and conclude in the interest of that method which enable a quick identification of the organism and the starting of a well adapted antibiotherapy.

Acute Disease↗
PubMed1980

[Assessment of left ventricular function in patients with aortic regurgitation using dynamic investigation (author's transl)].

To assess accurately left ventricular function (LVF) in patients with aortic regurgitation (AR pts), isometric exercise (IE) was used in association with postextrasystolic potentiation (PESP) during diagnostic heart catheterization including left cineventriculography in 16 pts with pure moderate or severe AR. The results were compared with those observed in 8 control pts (C pts). IE resulted in a significant increase in heart rate by 15 p. cent and in an increase in mean aortic pressure by 29 p. cent (p < 0.001). During IE, LV end diastolic pressure (EDP) remained unchanged in C pts and in 6 AR pts whereas this value was increased by 49 p. cent (p < 0.01) in 7 AR pts without a significant change in LV end diastolic volume. Ejection fraction (EF) was decreased in each AR pt (mean 14 p. cent; p < 0.001) and remained unchanged in C pts. A negative correlation was evidenced between the decrease in EF and the increase in LVEDP (r = 0.76). PESP resulted in a increase in EF in both C pts and AR pts (+ 25 and + 29 p. cent respectively; p < 0.001). PESP under IE resulted in a lower increase in EF than PESP under basal conditions (+ 19 and + 24 p. cent respectively) mainly due to the increase in after load provided by IE. Dynamic investigation of the LVF in AR pts is a physiological method of investigation easy to perform which may assess both LV contractile reserve and cardiac reserve. Such a method of investigation may help to select AR pts for surgery.

Adult↗
PubMedDate not supplied

Structure and sequence of the multihaem cytochrome c3.

The molecular structure of cytochrome c3 isolated from Desulfovibrio desulfuricans has been solved on the basis of its crystallographic determination at 2.5 A resolution and of an essentially complete sequence. The molecule consists of a single polypeptide chain wrapped around a very compact core of four non-parallel haems which present a relatively high degree of exposure to the solvent. Alignment of the amino acid sequences of cytochrome c3 from several species suggests that the structure reported here is characteristic of the cytochrome c3 group.

Amino Acid Sequence↗