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Biomedical subjects

F Lambert

Publications and source records attributed to F Lambert.

At least 37 records · Page 2Linked to original sources
PubMed1997

Effects of angiotensin converting enzyme inhibition on crossbridge properties of diaphragm in cardiomyopathic hamsters of the dilated bio 53-58 strain.

Crossbridge properties of cardiomyopathic Syrian hamster (CSH) diaphragm from the dilated Bio 53-58 strain were analyzed after 5-mo of treatment with the angiotensin converting enzyme (ACE) inhibitor perindopril (1 mg/kg/d by oral gavage). Three groups were studied: control F1B hamsters (C; n = 14); CSH given placebo (PL; n = 11 ); and perindopril-treated CSH (PE; n = 11). Peak isometric tension was lower in PL than in C, in both twitch (21.4 +/- 1.5 versus 46.9 +/- 1.5 mN/mm2; p < 0.001) and tetanus (41.0 +/- 2.7 versus 90.5 +/- 3.3 mN/mm2; p < 0.001). In PE, peak isometric tension was intermediate between C and PL, and was significantly lower than in C and higher than in PL. The single force of one crossbridge (pi), the number (m) of crossbridges, the turnover rate of myosin adenosine triphosphatase (ATPase) (kcat), and peak mechanical efficiency (Effmax) were calculated from A.F. Huxley's equations; m was lower in PL than in C, in both twitch (3.4 +/- 0.2 versus 4.9 +/- 0.2 10(9)/mm2; p < 0.001) and tetanus (4.0 +/- 0.3 versus 8.9 +/- 0.7 10(9)/mm2; p < 0.001); m was higher in PE than in PL, in both twitch 4.3 +/- 0.5 versus 3.4 +/- 0.2 10(9)/mm2; NS) and tetanus (6.2 +/- 0.4 versus 4.0 +/- 0.3 10(9)/mm2; p < 0.01), with no change in pi. In the three groups, Effmax correlated linearly with kcat (r = 0.93; p = 0.001) and showed a negative linear correlation with pi (r = 0.996; p = 0.001). In conclusion, our results show that in experimental cardiomyopathy, ACE inhibitor mainly helps to prevent a decrease in the number of diaphragm muscle crossbridges, resulting in preserved peak isometric tension.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Relaxation is impaired in the diaphragm muscle of the cardiomyopathic Syrian hamster.

Relaxation was examined in diaphragm muscle strips of cardiomyopathic Syrian hamsters and control hamsters. Isotonic lengthening velocity and isometric tension decay were analyzed over the load continuum in response to twitch. For each load level (P), we measured the maximum extent of shortening (deltaL), the peak lengthening velocity (VL), and the peak rate of tension decline (-dP/dtmax). The kinetics of sarcomere length (SL) were simultaneously measured by laser diffraction. In an attempt to account for the influence of shortening and/or load on relaxation, we calculated the slopes of the VL - deltaL and -dP/dtmax - P relationships. In both groups, there was a direct relationship between (1) VL and deltaL and (2) -dP/dtmax and P. In myopathic hamsters, we observed a decrease in the slope of the VL - deltaL relationship (p < 0.05), a decrease in VL at any common value of both muscle and sarcomere extent of shortening, and an increase in the duration of overall lengthening. Isometric tension decay was significantly prolonged in myopathic muscle strips, while the -dP/dtmax - P relationship was not significantly different than in controls. At low-to-medium loads, SLs at the onset of tension decline were greater in myopathy. These data indicate that relaxation of the diaphragm was both slowed and prolonged in myopathic Syrian hamsters.

Animals↗
PubMed1997

Developmental changes in crossbridge properties and myosin isoforms in hamster diaphragm.

The aim of this study was to determine the effects of maturation on crossbridge properties and myosin isoform composition in hamster diaphragm muscle. Diaphragm strips were obtained at postnatal Days 1 and 8 and in adults (10 to 12 wk). Peak isometric tension and maximum unloaded shortening velocity (Vmax) increased with age (p < 0.001). The single crossbridge force (pi), the total number of crossbridges normalized per cross-sectional area (m x 10(9)/mm2), the turnover rate of myosin ATPase (kcat), and peak mechanical efficiency (Effmax) were calculated from Huxley's equations. The value of m increased significantly from birth to adulthood (p < 0.001), with no changes in pi or Effmax; kcat increased significantly only after the first week postpartum. There was a strong linear relationship between peak isometric tension and m (p < 0.001). Conversely, changes in Vmax were not related to kcat. Myosin electrophoresis showed that neonatal bands and slow myosin isoforms (S) were present at birth. The number of fast adult myosin isoforms increased progressively from birth to adulthood, whereas S increased during the first week postpartum. In conclusion, development changes in diaphragm muscle force and myosin isoform composition were associated with changes in crossbridge number and kinetics, with no changes in the average force per crossbridge or in mechanical efficiency.

Age Factors↗
PubMed1997

[Oral Crohn disease. Apropos of a case].

An 18-year-old male patient treated for Crohn's disease for 3 years developed buccal manifestations. The oro-facial symptoms disappeared completely with systemic corticosteroid treatment. Diagnosis, pathological features, treatment and pathogenesis hypotheses are discussed.

Adolescent↗
PubMed1997

[Mechanical vascular clips with an automatic stapler in reconstructive microsurgery. Apropos of 16 clinical cases].

From October 1995 through March 1997, we performed 30 microsurgical reconstructions and achieved microvascular anastomoses in 16 with an automatic stapler (VCS) which allows insertion of titanium clips in the everted vessel walls. The mean age of the patients (15 men, 1 woman) was 42 years. Mean vessel diameter of the donor and recipient sites was 2 mm for the arteries and 3 mm for the veins. Recipient vessels had suffered radiation damage in 3 cases. Micro-anastomoses were performed in 26 cases, with end-to-end sutures in 24 and end-to side sutures in 2. There were 11 arterial procedures including 3 bypasses and 15 venous procedures with 1 bypass. Peroperative thrombosis occurred in 2 cases and were treated by undoing the anastomoses and resuturing manually. There were no early or late postoperative vascular complications. This clinical experience confirms the advantages of this mechanical approach to microanastomotic procedures for small vessels as previously demonstrated in experimental work: a system avoiding transfixation, rapid procedure, reliability.

Adult↗
PubMed1997

[Iatrogenic extravasations of cytotoxic or hyperosmolar aqueous solutions. Value of surgical emergency by aspiration and lavage].

Iatrogenic extravasations are characterized by their unpredictable course, the possible repercussions of functional, cosmetic and psychological sequelae, and the absence of a therapeutic consensus. The authors present the protocol used in Hôpital Saint-Louis, based on a synthesis of current procedures, consisting of emergency conservative surgical aspiration and lavage, performed in a context of close collaboration with oncolosits, intensive care physicians and radiologists. From 1994 to March 1997, fifteen patients were operated following extravasation during seven chemotherapeutic protocols, three radiographic examinations with injection of contrast agents and five resuscitation procedures. This simple protocol, applied systematically, achieved cure without cutaneous or functional sequelae in all patients. Aspiration-lavage during the first twelve hours therefore constitutes the treatment of choice of iatrogenic extravasation with cytotoxic or hyperosmolar aqueous solutions.

Aged↗
PubMed1996

[Fasciocutaneous flap of the posterior surface of the thigh with distal pedicle. Anatomical study and surgical value. A propos of 3 cases].

In the light of previous studies, the authors conducted an anatomical study on 21 cadaveric dissections with injection in order to define the characteristics of the distally based fasciocutaneous flap of the posterior surface of the thigh, described for the first time in 1988 by Maruyama. This leaf-shaped flap extends from the popliteal region to the gluteal sulcus. It possesses an axial arterial network derived from the popliteal artery, reinforced by the perforating arteries derived from the vessel or the profunda femoris artery. The venous return is ensured by venae comitantes and the communicating saphenous vein. The flap raising technique is described. From 1991 to 1994, 3 patients were operated in order to cover a defect of the knee (1 case) and amputation stumps (2 cases). The postoperative course was uneventful and the results were considered to be stable and of excellent quality with a follow-up of 2 to 4 years.

Adult↗
PubMed1996

[The folded fibula flap: anatomical study and clinical application to septic post-traumatic femoral reconstruction. A propos of 6 cases].

The reconstruction of extensive femoral defects, particularly septic, by revascularized free fibula flap has become part of routine practice for many years. Following the demonstration of secondary stress fractures, splitting of the fibula into two vascularized barrels was proposed in 1987 to avoid this complication. The authors conducted an anatomical study on 100 dry bones in order to define the situation of the fibular foramen which is usually found at about 1.45 cm from the midpoint of the fibula. This foramen must be spared during the intermediate splitting osteotomy in order to obtain two bone barrels: one with a double centromedullary and periosteal blood supply which will be used like a contromedullary pin, and the other with only a periosteal blood supply, which will be used as a medial or lateral splint. The deductions concerning the preoperative strategy and splitting technique are explained as a function of the length of the defect. From 1989 to 1993, 6 male patients underwent extensive femoral reconstruction (average length of 9.8 cm). Four free revascularized transfers were performed, including one osteocutaneous flap. In two cases, the osteocutaneous transfer was a proximally based island pedicle flap. Apart from one patient who was subsequently amputated, five patients underwent a secondary autologous bone graft after an average of three months. Consolidation was achieved after a mean of 12.6 months. A secondary stress fracture was observed in one case. With a minimum follow-up of two years, all patients are able to walk with a mean shortening of 2 cm of the reconstructed limb and without any donor site sequelae.

Adult↗
PubMed1995

Relations between myocardial contractility, myosin phenotype, and plasma angiotensin-converting enzyme activity in the cardiomyopathic hamster.

Angiotensin-converting enzyme (ACE) inhibitors have been shown to preserve myocardial contractility in the cardiomyopathic Syrian hamster (CSH). To determine if this was related to changes in myosin heavy-chain (MHC) phenotype, myosin isoform patterns and mechanical properties were studied in the same left ventricular papillary muscle from CSH of the Bio 53.58-dilated strain. From age 1 to 6 months, 22 CSH randomly received either perindopril 1 mg/kg/day in distilled water (PE, n = 11) or distilled water only (PL, n = 11), and seven control golden Syrian hamsters (C) received distilled water by force-feeding. Compared to C, PL had a lower Vmax (p < 0.01), a lower amount of alpha-MHC (p < 0.01), and an unchanged twitch duration. In PE, as compared to PL, there was a higher Vmax (p < 0.05), a higher alpha-MHC (p < 0.05), and an unchanged twitch duration. There was a positive relationship between Vmax and alpha-MHC in the population taken as a whole (p < 0.01), and when muscles from C and PL groups were plotted together (p < 0.001), but neither within each group, nor when PL and PE were plotted together. Our study indicates that in CSH (a) the preserved contractility with ACE-inhibitor treatment is associated with limitation of isomyosin shift induced by the myopathic process, but no cause-to-effect relationship could be demonstrated on the basis of our data, and (b) adaptive changes in twitch duration were not observed either in untreated CSH or in perindopril-treated CSH, despite significant changes in alpha-MHC content.

Animals↗
PubMed1995

Sarcoplasmic reticulum Ca2+ pumps in heart and diaphragm of cardiomyopathic hamster: effects of perindopril.

The polymyopathy of the Syrian hamster is associated with alterations of cellular calcium regulation and contractile performance of cardiac and skeletal muscles and, in particular, the diaphragm. Angiotensin-converting enzyme (ACE) inhibitors have been shown to preserve contractile performance. Therefore we analyzed the expression of the genes coding for the sarco(endo)plasmic reticulum Ca(2+)-adenosinetriphosphatase (SERCA) in heart and diaphragm of the cardiomyopathic Syrian hamster (CSH) from the dilated strain Bio 53-58, and we tested the influence of ACE inhibition on accumulation of the different SERCA mRNAs. In the diaphragm of healthy hamsters, two SERCA mRNA isoforms were present: SERCA 1 and SERCA 2. At 6 mo of age, the myopathic process resulted in decreased levels of SERCA 1, whereas the level of SERCA 2 was unchanged. The ACE inhibitor perindopril (1 mg.kg-1.day-1), administered by force feeding from 1 to 6 mo of age, had no effect on the SERCA 1 mRNA level. In heart, the myopathy was associated with a depressed level of SERCA 2 mRNA in 9- but not in 6-mo-old animals. Perindopril treatment from 6 to 9 mo reversed cardiac hypertrophy and the relative decrease in SERCA 2 mRNA level. Preventive treatment with perindopril from 1 to 9 mo tended to prevent (not significantly) the development of cardiac hypertrophy and reduction in SERCA gene expression. In conclusion, the myopathic process affects SERCA gene expression in the diaphragm and subsequently in the heart. Perindopril treatment can prevent SERCA mRNA loss in heart but not in diaphragm.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

[Posterolateral sural fasciocutaneous island flap with proximal aponeurotic pedicle. Anatomical study and use for cutaneous cover of the knee. Apropos of 9 clinical cases].

The authors propose an elaborate variant of the classical saphenous or lateral leg fascio-cutaneous flap with a proximal pedicle for the cover of post-traumatic skin defects of the knee. The original feature of this flap resides in the purely aponeurotic or adipo-fascial pedicle which increases the arc of rotation, while minimizing cutaneous sequelae of the donor site. Twenty four injected cadaveric dissections were used to define the neurovascular content of the lateral sural fascia: the lateral and medial superficial sural arteries and their territory of perfusion, accompanying veins and the short saphenous vein, as well as the lateral and medial sural cutaneous nerves. The technique of harvesting of the island flap is described. Nine patients were operated between 1991 and 1994, with an uncomplicated postoperative course in terms of flap vitality and donor site. The skin cover of the knee was considered to be of excellent quality, stable and sensitive, with a follow-up ranging from 6 months to 3 years four months.

Adult↗
PubMed1994

[Reconstruction of the long fingers using toe transfers].

The authors review 29 toes transfers on 24 patients with injury of long fingers between 1985 and 1990. The series contains 16 complete toes and 13 partial toes transfers. The results, inconvenience and indications are discussed.

Adolescent↗
PubMed1994

[Fascia superficialis temporalis in facial reconstructive surgery. Apropos of 35 cases].

The fascia superficialis temporalis (FST), one of the planes of cranial cover, can be raised to form an axial pedicle flap or a vascular island flap on superficial temporal vessels. Its fibrovascular structure, the area able to be raised and the possible addition of other superficial tissues (scalp, forehead skin) and deep tissues (calvarial bone) mean that this flap can be used in surgery of the external and intracavitary facial contours and shapes. The authors report their experience of 35 facial reconstructions: 7 ear reconstructions, 5 suspensions of a paralysed labial commissure, 10 conjuctivo-palpebral revisions, repair of 5 subcutaneous defects, 3 haired resurfacings, 1 inferior labial, 1 cheela, 1 orbitomalar reconstruction, 1 malo-commissuro-labial repair, 1 prefabricated free flap. The donor site sequelae were considered to be negligible: 1 case of temporal anaesthesia with dysaesthesiae, 4 cases of band alopecia. The analysis of these 35 reconstructions reveals the quality of all cases of defect repair, especially palpebral; the ease and persistence of suspensions of the labial commissure; the value of FST as a conjunctival and buccal mucosal substitute; the density of the hair contribution. However, total or partial ear reconstruction using this technique constitutes a more limited indication.

Adolescent↗
PubMed1994

[Reformatting 3-dimensional medical images. Application to MRI and scanners].

Several kinds of images, each giving a different information, are now available to radiologists. The MRI images have excellent contrast resolution and enable soft tissues to be differentiated, but they do not distinguish structures with low water content, notably air and bone, whereas these are easily recognized by CT. The aim of this study is to present a simple, entirely radiologist-supervised method to examine the radiological data of any patient, obtained from several kinds of images. MRI is performed using a GEMS Signa, 1.5 Tesla, 4.9 version magnet. Acquisitions are T1- or T2-weighted spin-echo or gradient sequences, with a 256 or 512 matrix, on axial sections, with of without contrast injection. CT is performed using a GEMS Hi Speed scanner. Acquisitions are obtained on a 512 matrix and with a "Soft" or "Bone" filter, without contrast injection. The two series of sections are transmitted, through an Etherne network, to a Sun console where the two corresponding volumes are reconstructed on a GEMS Voxtol by means of a 3-dimensional soft ware for image treatment. At least 3 couples define the rotation and translation required for one of the two volumes to reset it in the guide mark of the other. The soft ware then looks for the best transformation, in terms of least square, between the two 3-dimensional volumes. The calculation demands only a few seconds. One of the two objects is then recalculated in the guide mark of the other. The cursor positioned by the user on any point of the object is linked to a second cursor which will automatically position itself on the corresponding point of the other object. The accuracy obtained (about one millimeter) is specified by the soft ware which indicates how to improve resetting. In addition to its teaching value, this superimposition image can help in the diagnosis and can be used for surgical stimulation because it is possible to mix the images. This mixing gives access to a new type of imaging, since the images spared can be reconstructed in volume, and treated in all planes, as a CT or MRI examination. The term "Anatomical Reconstruction Images" may be suggested for this new type of examination. Beside intermodal comparison, one may also imagine that the soft ware can be used to follow up the patient over time (repeat MRI) or to make comparisons between several objects, although the elastic resetting method is more often appropriate in the second case.

Contrast Media↗
PubMed1993

Myocardial effects of early therapy with perindopril during experimental cardiomyopathy.

The effects of chronic angiotensin-converting enzyme (ACE) inhibition on intrinsic myocardial contractility of the failing myocardium have been poorly documented. In the present study, inotropy, lusitropy, and economy of force generation were studied in vitro in papillary muscles from cardiomyopathic Syrian hamster (CSH) under early perindopril therapy, i.e., therapy begun at a stage when experimental heart failure was not yet observed. One-month-old CSH from the dilated strain Bio 53.58 were randomly treated over a 5-month period with either the ACE inhibitor perindopril 1 mg/kg/day (n = 11) or placebo (n = 11), and 7 age-matched controls were given placebo. Compared with control, placebo had a lower maximum shortening velocity (Vmax) (p < 0.01) and normalized total force (p < 0.05), and a lower curvature of the force-velocity relationship (p < 0.01). It has been shown that the higher the value of the curvature, the better the myothermal economy of force generation. Compared with placebo, perindopril had a 68% inhibition of plasma ACE activity and a greater Vmax (p < 0.05), whereas total force/mm2 was similar. This resulted in a lesser decrease of the curvature compared to control (p < 0.05). Placebo had a decreased peak lengthening velocity and rate of force decline. However, compared to control, no intrinsic abnormalities of the relaxation phase were observed in either placebo or perindopril when relaxation parameters were corrected for the lower systolic performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Sarcoplasmic reticulum calcium transport and Ca(2+)-ATPase gene expression in thoracic and abdominal aortas of normotensive and spontaneously hypertensive rats.

Increased intracellular Ca2+ concentration has been associated with the elevation of vascular tone in hypertensive animals. The increase in free cytosolic Ca2+ may partially result from a reduced activity of the sarcoplasmic reticulum (SR) calcium pump. Accordingly we investigated the Ca2+ transport function and the expression of the Ca(2+)-ATPase gene in thoracic and abdominal aortas of normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). Total SR Ca2+ pump activity was estimated by measuring the oxalate-stimulated Ca2+ transport rate on crude homogenates. Ca2+ transport was also measured on highly active microsomal fractions. Our data indicate that the Ca2+ uptake rate, expressed per mg of protein or per g of muscle, is greater in homogenates from aortas of SHR when compared with that of WKY rats. In microsomal fractions isolated from thoracic aortas of SHR compared with WKY rats, the activity and density of SR Ca2+ pump were only slightly increased. The SR Ca2+ transport rate and the amount of each SR Ca(2+)-ATPase mRNA isoform, i.e. SERCA 2a and SERCA 2b, normalized to 18 S ribosomal RNA, were greater in thoracic than in abdominal aorta in both strains. When compared with WKY rats, the level of each SERCA mRNA isoform is higher in the abdominal aorta of SHR but appears similar in the thoracic aorta. Thus, in contrast to previously published data that documented a depressed SR Ca2+ transport activity in the aorta of SHR, the present data indicate that the SR function is increased. These changes in SR activity are accompanied by quantitative changes in expression of the SR Ca(2+)-ATPase gene without alterations in the SR Ca(2+)-ATPase mRNA isoforms pattern.

Animals↗