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Biomedical subjects

C Bour

Publications and source records attributed to C Bour.

At least 19 recordsLinked to original sources
PubMed1999

Subcellular localization of meta-tetra (hydroxyphenyl) chlorin in human tumor cells subjected to photodynamic treatment.

Subcellular localization of meta-tetra (hydroxyphenyl) chlorin (mTHPC) in HT29 human colon adenocarcinoma cells has been studied by means of fluorescence microscopy. The observed diffuse intracellular distribution of mTHPC fluorescence outside the nucleus indicates general staining of cellular organelles. No changes in dye fluorescence pattern are evident during and immediately after cell illumination. Alternatively, the changes in mTHPC fluorescence pattern are observed upon subsequent cell incubation, and are characterized by the appearance of distinct bright fluorescence zones. Reaching a maximum 1 h after illumination, modifications of the fluorescence pattern then gradually disappear in parallel with the formation of plasma membrane blebs, suggesting that cell necrotic lysis is taking place. Photosensitized damage to mitochondria and the Golgi apparatus has been studied using fluorescent probes 1 h after irradiation, the stage of extensive cytoplasm vacuolization, and reveal alterations of these organelles. Changes in the mTHPC fluorescence pattern and mTHPC photocytotoxicity, as measured by the MTT test 24 h after illumination, are inhibited by sodium azide, a singlet oxygen quencher.

Fluorescent Dyes↗
PubMed1998

The posterior interosseous nerve and the radial tunnel syndrome: an anatomical study.

Twenty anatomical specimens were carefully studied in order to establish a possible connection between the posterior interosseous nerve and the radial tunnel syndrome. Our results show that the posterior interosseous nerve distal to the supinator muscle may be compressed by various structures. These include the distal border of the supinator muscle, the ramifications of the anterior and posterior interosseous vessels, and the septum between the extensor carpi ulnaris and the extensor digitorum minimi. The posterior interosseous nerve is also stressed during passive supination (elongation and rotation), and during passive pronation (compression). This suggests that the interosseous nerve distal to the supinator muscle should be explored in radial tunnel compression syndromes.

Aged↗
PubMed1998

Intracellular distribution of tamoxifen in resistant human breast adenocarcinoma cells using tamoxifen-eosin association.

A tamoxifen-resistant cell line (MCF7TAM) was established from tamoxifen-sensitive MCF-7 human breast cancer cells expressing estrogen receptors. Though the resistant cell line grows in the presence of tamoxifen, estrogen receptors continue to be expressed at similar levels as in the parental cell line. However, estrogen receptors appeared to be altered in the resistant cell line since important discrepancies are observed between results obtained with ligand binding assays and immunoenzymatic assays, tending to show modifications of estrogen receptor ligand binding capacity. The intracellular distribution of tamoxifen in sensitive and resistant cell lines was investigated using fluorescence of eosin-tamoxifen ionic association. Fluorescence emission spectra of eosin, tamoxifen and eosin-tamoxifen complex (lambda(ex)=480 nm) were analyzed and the maximal fluorescence intensity found for the complex (lambda(em)=540 nm) was four times higher than that of eosin alone, while tamoxifen alone did not emit any fluorescence in this spectral range. In MCF-7 cells, tamoxifen was found to be mainly located surrounding the nucleus, although nuclear fluorescence intensity was significantly lower. No highly fluorescent granules were observed in the resistant cell lines as opposed to sensitive cells. Improvement of this fluorescence microscopy methodology could appear of interest, taking into account the complexity of tamoxifen resistance molecular pathways.

Adenocarcinoma↗
PubMed1998

Influence of SDZ-PSC833 on daunorubicin intracellular accumulation in bone marrow specimens from patients with acute myeloid leukaemia.

The multidrug resistance (MDR) modulating activity of SDZ-PSC833 (PSC), a non-immunosuppressive cyclosporine analogue, was investigated and compared with cyclosporin A (CSA) in bone marrow clinical specimens from 45 patients with acute myeloid leukaemia (AML) taken at diagnosis, using double-labelling flow cytometry with simultaneous determination of P-glycoprotein (PGP) expression and intracellular daunorubicin fluorescence (IDF). On the basis of pre-clinical results in multidrug-resistant K562 leukaemic cells, concentrations leading to iso-effective complete restoration of IDF were used: 5 and 10 micromol/l, respectively for PSC and CSA. In the clinical specimens, PGP expression was correlated with a significant decrease in IDE PSC was found to be significantly more potent than CSA since it was found to induce a significant increase in IDF in a higher number of cases and to a higher extent than CSA. PGP-unrelated activity of PSC was also observed in specimens expressing no PGP but exhibiting low IDF, thus probably expressing alternative resistance mechanisms. The results confirm the potency of PSC as MDR-modulating agent in clinical AML specimens whose resistance pattern differed from that of highly resistant cell models and suggest that the activity of PSC is not limited to P-glycoprotein inhibition.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Scapho-trapezio-trapezoid arthrodesis in the treatment of Kienböck's disease. A study of 16 cases.

Sixteen scapho-trapezio-trapezoid arthrodeses were performed for Kienböck's disease. In ten cases, a prosthetic replacement of the lunate was inserted at the same time. Clinical results were good with regard to pain and fair with regard to grip strength which was improved by an average of 32%. In contrast, the arc of flexion-extension was 38% less than on the unoperated side. Long-term radiographic assessment showed the efficacy of the procedure in maintaining carpal height. Biomechanical observations and a review of poor results showed the limits of the method and the importance of correct positioning of the scaphoid. We concluded that triscaphe arthrodesis was a useful procedure for the treatment of Kienböck's disease in Decoulx's stage 3.

Adult↗
PubMed1992

[Lipofibroma of the median nerve. Apropos of a case].

Lipofibroma is a rare, benign nerve tumour corresponding to diffuse fibroadipose infiltration of the nerve, dissociating the fasciculi without invading them. The authors report a case of lipofibroma of the median nerve in a 32 year old man presenting with a soft swelling of the palmar surface of the thumb. Treatment consisted of intraneurodissection of the tumour arising exclusively from the medial collateral nerve of the thumb. With a follow-up of two years, there has been no recurrence of the tumour, but the patient has persistent decreased sensation of the ulnar half of the thumb pulp. The features of the lipofibroma and the therapeutic options are discussed in the light of the data reported in the literature.

Adult↗
PubMed1991

Human nerve xenografting in nude mouse: experimental study of graft revascularization.

In the nude mouse, the congenital absence of T lymphocytes makes it possible to implant human nerve grafts without rejection or iatrogenic modifications (by immunosuppression) of human and murine tissues. Medial antebrachial cutaneous nerves were harvested from human cadavers 1-18 hours after death. These nerve grafts were implanted using different techniques in nude mice. All the grafts were macroscopically and microscopically revascularized 3 days after implantation. The modifications in time of this vascularization could be studied with precision through the use of repeated biopsies. The absence of human blood group antigens on the neovessel endothelium suggested a murine origin for angiogenesis. In situ DNA hybridizations with human and mouse DNA confirmed this origin. The topography of the revascularization (maximal in the perineurium and endoneurium) and the almost complete absence of human cells other than Schwann cells in the grafts at the peak of angiogenesis (26 days after grafting) suggested that Schwann cells had a determining role in graft vascularization. The irradiation of the nerve grafts with a dose of 30 grays before implantation did not modify significantly their histologic appearance compared to the control group, whereas an irradiation of 60 grays led to massive lesions. The neurotization of murine axons led to chimerical structures of normal histologic appearance, with vascularization similar to that observed in nonneurotized nerves. Through chimerism (human Schwann cells, murine vessels and axons) this model makes it possible to dissociate the respective role of the host and of the nerve graft in angiogenesis and suggests the existence of growth factors produced by the human Schwann cells.

Adult↗
PubMed1991

[Arthrodesis of the wrist in manual workers. Apropos of 36 cases].

We present a review of 36 patients with final radiocarpal arthrodesis done between 1976 and 1987. The series was homogeneous: patients were about 40 years old and lesions were work-related. The most frequent reason for the arthrodesis was fracture of scaphoid bone, followed by Kienbock's disease complex trauma of carpus, severe carpal sprain, and articular fracture of the distal fourth of radial bone. Thirty-one arthrodeses were done by screwed-on iliac graft, 5 by nailing following Mannerfelt technique. The two main factors in functional results were pain and loss of strength. The latter averaged 41 per cent of that of the normal side, and only 8 wrists were completely free of pain. Indications for final radio-carpal arthrodesis are discussed, taking into account the poor functional results and their repercussions on social and professional life of the patient.

Accidents, Occupational↗
PubMed1991

[Partial toe transfers. Functional results: apropos of 26 cases].

We present our results from a series of 26 partial toe transfers (11 pulp transfers and 15 composite tissue transfers) performed in posttraumatic reconstruction of the thumb (22 cases) and fingers II to V (4 cases). There was one failure due to arterial thrombosis. The results for sensitivity were satisfactory after pulp transfer (Weber-average of 9 mm), less satisfactory after composite transfer. Recovery of mobility and strength usually were satisfactory. Problems with the donor foot were mainly slow healing and poor tolerance to cold; the latter was experienced by 1/3 of the patients although functional deficits were rare. Partial toe transfer is used at present for distal reconstruction of the thumb, and leaves the metacarpophalangeal joint intact. There are basically two techniques: "tailored" transfers from the big toe for amputations of the distal phalanx of the thumb, and wrap-around flap of Morrison for amputations proximal to the proximal phalanx.

Adolescent↗
PubMed1991

[Scapho-trapezo-trapezoidal arthrodesis or triscaphe arthrodeses. Study of 36 reviewed cases].

From May 1983 to September 1988, we performed 41 triscaphe arthrodeses, 36 of which underwent clinical and radiologic follow-up examination. The 36 preoperative diagnoses were classified as: Kienböck's disease (16 cases), chronic rotatory subluxation of the scaphoid (static scaphoid-lunate dissociation) (13 cases), degenerative arthritis of the scapho-trapezio-trapezoid joint (4 cases), traumatic lesion of the scapho-trapezio-trapezoid joint (2 cases), 1 case of midcarpal instability with a non-dissociative VISI pattern. Average length of follow-up was 28 months. Analysis of results showed on the whole good improvement on pain and average improvement of strength; range of motion varied greatly with etiology. For example, the range of motion on the fused side in Kienböck's disease averaged 38 per cent of that of the unoperated side, whereas in other conditions it averaged 60 per cent. Radiographic analysis confirmed the efficacy of triscaphe arthrodesis in preserving normal carpal height but revealed radial styloid impingement in 34 per cent of the cases. Use of this procedure should be limited to stage 3 Kienböck's disease and to scaphoid-lunate dissociation without arthritis. Peroperative radiographic study is indispensable to verify appropriate reduction of the scaphoid and to measure the radial-scaphoid angle. Partial radial styloidectomy should be included routinely in the procedure.

Adult↗
PubMed1989

[The socio-economic costs of finger replantation. Apropos of 40 replantations of the thumb].

Microsurgical techniques are becoming increasingly important in the emergency treatment of hand trauma and in secondary reconstructive surgery. In the light of the current concern with financial feasibility, we thought it important to determine whether this surgery, sometimes wrongly described as being luxury surgery, is economically feasible. The cost of 40 reimplantations and revascularisations of the thumb treated in the context of work accidents was studied. Although the short-term cost of reimplantation is higher than that of amputation, in the long-term, a successful reimplantation constitutes a definite economy for society and justifies this type of specialist surgery.

Amputation, Traumatic↗
PubMed1989

[A single-use vascular clamp. An experimental and clinical study].

Twelve rabbit femoral arteries were clamped for one hour with a TKS2 clamp in order to confirm the atraumatic nature of the Tamai disposable clamp. After 15 or 30 minutes of revascularisation, the arteries were excised and studied by light microscopy and scanning electron microscopy. Temporary dilatation of the artery was observed after removal of the clamp, as the patency test was always positive. Light microscopy revealed parietal flattening without any cellular disorganisation and scanning electron microscopy revealed flattening of the endothelial cells without any tearing. On the basis of these favourable results, combined with the ease of use, we now use the Tamai clamp daily.

Animals↗
PubMed1989

[Claw nails. Apropos of 16 cases treated by nail recession flap].

16 patients (75% women) were operated for a claw nail involving one of the three middle fingers. In 14 cases out of 16, a traumatic amputation, treated by directed healing in 60% of cases, was responsible for the deformity. The average loss of bone substance was 49% (range: 0-90%). The average shortening was 5 mm. The loss of substance was repaired by a local flap in 14 cases. Two early recurrences led to one failure and one good result after a second recession flap. One case of arthritis of the distal interphalangeal joint and one case of septic necrosis of the nail bed were also observed. Eleven subjects were reviewed with a mean follow-up of 4 years (1-7 years). The range of movement of the distal interphalangeal joint was always normal. The pinch force and the growth of the nail were normal in 75% of cases. The finger was cumbersome in one half of cases and 60% of patients complained of pain. Recurrences were observed in 50% of cases and the patients were disappointed in 64% of cases. This is a minor operation in terms of vascular elements, but it is associated with a high rate of recurrence and leaves a short finger. Its indications should be limited to losses of bone substance less than 50%.

Adolescent↗
PubMed1989

Tendon transfers for treatment of the paralyzed hand following brachial plexus injury.

The correction of functional deficits of the hand after a brachial plexus lesion is difficult; treatment should be provided by a well-knit team of surgeons and therapists. The patient should be fully aware of the limitations of surgical treatment before surgery, and should be entrusted to the care of a physical therapist during the critical period of nerve regeneration after initial surgical treatment to ensure optimal results. This article presents therapeutic possibilities and discusses specific problems of tendon transfers in brachial plexus palsy.

Brachial Plexus↗
PubMed1988

Effects of cyclosporin A and predegeneration on survival and regeneration of peripheral nerve allografts in rabbits.

Axonal regeneration across 64 median nerve grafts in 34 rabbits was studied histologically to determine the optimal conditions for nerve allografting. Axonal regeneration across allografts in cyclosporin A-treated animals was satisfactory, but it occurred more slowly and with more inflammation and fibrosis than in autografts. Without immunosuppression, fresh allografts were rejected. However, in immunocompetent hosts, allografts rendered less immunogenic by predegeneration were not rejected, and axonal regeneration occurred. The combination of cyclosporin A and nerve graft predegeneration produced the most substantial axonal regeneration, comparable to autografts. The observations suggest that nerve allograft survival may be optimally effected by cyclosporin A treatment coupled with reduction in the immunogenicity of the grafts, such as by predegeneration.

Animals↗