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Biomedical subjects

R Lemaire

Publications and source records attributed to R Lemaire.

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

Selective induction of the secretion of cathepsins B and L by cytokines in synovial fibroblast-like cells.

We have investigated the potent influence of some cytokines, tumour necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and interferon-gamma (IFN-gamma), on the secretion of cysteine proteinases (cathepsins B and L) by cultured synovial fibroblast-like cells from patients with rheumatoid arthritis (RA). After treatment of synovial fibroblast-like cells with cytokines, culture media were evaluated for cathepsins B and L by enzyme immunoassays, and for cathepsin B and L activities using the enzymatic substrates. Z-Phe-Arg-AMC and Z-Arg-Arg-AMC, and specific inhibitors. Treatment of synovial fibroblast-like cells with TNF-alpha or PDGF resulted in a marked increase in cathepsin B secretion. Moreover, after prolonged PDGF treatment, the amount of secreted cathepsin B returned to the low control level. In contrast, bFGF led to increased cathepsin L secretion. IFN-gamma induced both cathepsin B and L secretion. Our results show that cytokines induce a selective secretion of cathepsins B and L by synovial fibroblast-like cells. This selective effect of cytokines on the secretion of cysteine proteinases suggests that synovial fibroblast-like cell-mediated articular degradation is a highly regulated process.

Arthritis, Rheumatoid↗
PubMed1996

"Telepsychometry": a remote psychometry consultation in clinical gerontology: preliminary study.

OBJECTIVE: Evaluation of the clinical feasibility of remote psychometric consultation with elderly patients. METHODS: Remote consultation with six women and four men (average age 87) was compared with a standard consultation. An interview and two psychometric tests were used: the Mini-Mental Status Examination (MMSE) and the Clock Face Test (CFT), which were administered by a clinical psychologist and controlled by a psychologist observer who remained in the room with the patient. The experimental setting consisted of two rooms linked by a coaxial cable. Each room was equipped with a camera, television screen, and microphone. The clinician was able to operate the mobile camera in the patient's room by remote control. The clinician was assisted by a computer, which helped to focus on standardized points. A video camera recorded the consultation for documentation purposes. RESULTS: Decreased performance was observed in the remote versus the standard consultation for both tests (MMSE: p = 0.008; CFT: p = 0.006). Physiologic hearing loss may have been responsible for a fall in the patients' attention. CONCLUSION: Remote psychometric consultation can be applied successfully to the psychological examination of elderly patients provided that communication problems are solved.

Aged↗
PubMed1996

[Radiological study of the migration of prosthetic implants following hip arthroplasty].

Migration of the acetabular and femoral implants after THR is a better index of the stability of the bone-implant interfaces than are clinical or radiological results. Roentgenstereophotogrammetry (RSA) studies 3-D migration of the implants with high accuracy (0.15 to 0.28 mm for linear migrations). RSA presents several drawbacks which restrict its use to prospective studies on small numbers of patients. Simpler methods have therefore been developed to assess 2-D migration on standard films in retrospective studies. The precision of these "simple" methods is limited, due to several factors: the difficulty to define reliable landmarks on femur or pelvis, sometimes even on implants, measurement errors, related to variations in radiographic technique (focal distance, beam centering, patient positioning). Sutherland, Wetherell and Nunn have proposed methods with an accuracy around 2-3 mm. It appears impossible to correct migration measurements for distorsions due to patient positioning; the EBRA method was therefore developed to reject non-comparable films using a comparability algorithm. A precision of 0.20 to 0.32 mm can thus be reached for the study of cup migration. The same pitfalls are encountered in assessment of migration of the femoral implant; a preliminary theoretical study is mandatory for every implant studied. The data presently available show that migration at 2 years is predictive of the long-term evolution of an implant; for the cup, migration of 1 mm or more at 2 years is predictive of late failure, and similar conclusions can be drawn regarding the femoral implant. The 2-D assessment of implant migration using a correct "simple" method provides a mean to evaluate a new implant or an innovative technical modification in a reasonable amount of time, on a limited number of patients.

Acetabulum↗
PubMed1994

High-dose aprotinin reduces blood loss in patients undergoing total hip replacement surgery.

BACKGROUND: Aprotinin, a proteinase inhibitor, has been reported to reduce blood loss significantly during cardiac surgery. The mechanisms of this effect remain unclear. We studied the effect of aprotinin on blood loss and transfusion requirement during total hip replacement. Potential mechanisms of action and side effects also were investigated. METHODS: Forty patients scheduled for primary total hip replacement were randomized to receive, in double-blind fashion, either aprotinin given as a bolus of 2 x 10(6) kallikrein inactivator units (KIU) followed by an infusion of 5 x 10(5) KIU/h until the end of surgery or an equivalent volume of normal saline. Anesthesia and surgical techniques were standardized and systematic deep venous thrombosis prophylaxis was used. Peri- and postoperative blood loss and transfusion were measured. Fibrinolysis, coagulation pathways, and platelet function were assessed. Renal and hepatic function as well as the incidence of deep venous thrombosis also were assessed. RESULTS: Aprotinin reduced total blood loss from 1,943 +/- 700 ml to 1,446 +/- 514 ml (P < 0.05). This reduction of blood loss occurred during surgery (P < 0.05) and postoperatively (P < 0.001). Total amounts of blood transfused were 3.4 +/- 1.3 units/patient in the control group and 1.8 +/- 1.2 units/patient in the aprotinin group (P < 0.001). The activated partial thromboplastin time was significantly prolonged by aprotinin immediately after surgery, at 50.6 +/- 12.4 versus 32.3 +/- 4.6 s in control patients (P < 0.001), but results of the other coagulation tests were not different between the two groups. No side effects were observed in the aprotinin group. The incidence of deep venous thrombosis in the two groups was not significantly different. CONCLUSIONS: The use of high-dose aprotinin during total hip replacement results in a reduction in both blood loss and the amount of blood transfused. Aprotinin's mode of action, however, remains to be elucidated.

Aged↗
PubMed1994

Synovial fibroblast-like cell transfection with the SV40 large T antigen induces a transformed phenotype and permits transient tumor formation in immunodeficient mice.

OBJECTIVE: To understand the intracellular signals leading to transformed-like growth of synovial fibroblast-like cells from patients with rheumatoid arthritis (RA). METHODS: Cell lines stably transfected with one or both of 2 complementary oncogenes, the SV40 large T antigen and the ras oncogene, were studied for phenotypic changes. RESULTS: Synovial fibroblast-like cells stably transfected with the SV40 large T antigen, but not the ras oncogene, showed high levels of growth factor independent proliferation, grew under anchorage independent conditions, expressed cathepsin L mRNA, and formed transient tumors in immunodeficient mice. Synovial fibroblast-like cells stably transfected with both oncogenes appeared phenotypically similar to synovial fibroblast-like cells transfected with the large T antigen alone. CONCLUSION: The SV40 large T antigen confers a phenotype on synovial fibroblast-like cells similar to that stimulated by growth factors, suggesting that it stimulates the same intracellular signalling pathway leading to cytokine induced, transformed synovial fibroblast-like cell growth. When injected into immunodeficient mice these transfected cells formed tumors characterized by rapid, transient growth, central necrosis, and neutrophil infiltration.

Animals↗
PubMed1994

[Larsen syndrome: multicenter study of 12 new cases. Diagnosis, planning and results of treatment].

Larsen's syndrome is characterized by the association of congenital knee, hip and elbow dislocations, characteristic facial abnormalities, joint hyperlaxity, and other inconstant malformations. A review is made after description of 12 new cases from a multicenter study. A partial modification of diagnostic criteria is proposed, based on the analysis of the frequency and localization of the deformities. Radiological aspects, surgical indications, clinical evolution, complications and late results are presented, with emphasis on lower extremity problems. Good clinical results are more remarkable in the children treated early. Periodic follow-up is obligatory for good therapeutic results.

Abnormalities, Multiple↗
PubMed1993

[Prosthetic knee arthroplasty: current status and future perspectives].

Prosthetic replacement of the knee-joint has become an accepted method of treatment for osteo-arthritis and various inflammatory, metabolic or hematologic conditions of the knee-joint. It usually makes use of semi-constrained resurfacing prostheses which belong to several types differing by their degree of constraint and their intrinsic stability which are related to implant geometry and implantation technique. Ancillary instruments have been developed which make it possible, provided the rationale of the operation is well understood, to reproducibly attain the goals of the operation, i.e. limb realignment, ligament balance in flexion and extension, adjustment of joint-line level and correct patellar tracking. Improvement in the clinical outcome of the operation has also resulted from better rehabilitation and postoperative treatment, particularly to prevent local and systemic complications.

Aged↗