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Biomedical subjects

M Bonnin

Publications and source records attributed to M Bonnin.

At least 37 records · Page 2Linked to original sources
PubMed1996

The weight-bearing knee after anterior cruciate ligament rupture. An in vitro biomechanical study.

Unilateral weight bearing was simulated on 12 cadaver knees to quantitate anterior tibial translation (ATT) after anterior cruciate ligament (ACL) transection and to asses the role of the posteromedial structure and the hamstrings in controlling laxity. With the ACL intact, ATT was 3.5 +/- 2.8 mm in extension and 4.3 +/- 3.6 mm at 60 degrees flexion. After sectioning the ACL, ATT was 6.5 +/- 4.7 mm in extension and 17.5 +/- 10 mm at 60 degrees flexion (P = 0.001). Applying a force in the hamstrings was unable to correct the pathological ATT observed after ACL section. Partial medial meniscectomy did not increase ATT after the ACL section. Disinsertion of the posterior horn of the medial meniscus and total medial meniscectomy increased ATT significantly compared to isolated ACL section. After ACL transection, sectioning the meniscotibial fibers or posteromedial capsule significantly increased ATT (6.5 +/- 0.5 mm in extension). Section of the postero-oblique ligament or popliteus tendon had no effect on ATT.

Aged↗
PubMed1996

[Representations, discourses and practices about drug substitution with opiates. Apropos of a survey conducted in cooperation with 97 French physicians].

In order to analyse the various factors which determine physician's position on the use of opiates in a substitution treatment--as a harm-reducting and heroin dependence treatment tool-, 97 French physicians (i.e. 47 general practioners, 36 psychiatrists, 10 internists, 4 emergency care practioners) answered anonymously 103 closed questions, in presence of a single investigator. Among these 97 physicians, 40 were choosed at random from a list of addiction treatment's practioners, 19 were choosed nominatively for their explicit point of view toward substitution, and 38 were choosed at random from the Herault physicians register. In this latter sample, the survey showed a majority of physicians took an ambivalent position towards substitution, or were favourable without being prescriptors themselves--even though meeting drug users-. General practioners were more favourable to drug substitutes than specialists (50% vs 22%). This practice appeared as legitimate for 70% of physicians; AIDS helped justify this attitude for 26% of the specialists and 5% of the general practioners. Individual or socio-professional factors, the representations of the drug-addict and of his suffering, the perceptions of AIDS contamination risk and the standards of knowledge on the substitution treatments did not differ significatively (p < 0.02) between the groups, determinated according to the expressed practioners point of view toward substitution. Using a method exploring opinion structuration, no description of the typical doctor can be drawn from his position towards substitution. Militant discourses were rare; the main disagreements concerned the status, the negotiation around "the product ... or the medicament" within the drug addict-physician relationship should have. Substitution was considered by some as a mere shift from one object of dependence to another; and to others, as a means of setting up a therapeutic relationship. Ambivalent opinions frequently noticed in the physician's point of view towards substitution appears as a multifactorial phenomenon. Not only does it reveal the physician's difficultie in adapting previous patterns of treatment which are not longer adequate to a critical situation, but it also questions the foundations of the very relationship between the practioner and the drug addict.

Attitude↗
PubMed1995

CT and MRI evaluation of tenosynovitis of the rheumatoid hindfoot.

Thirty-nine patients with rheumatoid arthritis who had presented with tarsitis before, were investigated at the level of the rearfoot. The first 17 patients had CT with previous tenography when it was possible; the following 22 patients had MRI with gadolinium injection. Tendon involvement appeared in 52.9% of the cases on CT, and in 90% of the feet on MRI; therefore, in case of clinical or radiological signs of tarsitis, it appears that tendon involvement must be suspected. With the two procedures the tibialis posterior tendon lesions were very predominant. In the majority of the patients (31/39), there was associated involvement of two or more tendons. If there is a ruptured tendon, the authors think that one must be cautious with surgical tendinous transfer; indeed, the long-term results of this surgical procedure present a strong probability of being compromised in rheumatoid arthritis which is a progressive disease.

Adult↗
PubMed1995

[Arthrodesis of the ankle under arthroscopy. Apropos of 10 cases reviewed after a year].

PURPOSE OF THE STUDY: The technique, results and indications for arthroscopic ankle fusion are detailed and compared with open technics. MATERIAL AND METHODS: 10 arthroscopic ankle fusions were performed between 1991 and 1993. This procedure was used in 4 cases of rheumatoid arthritis, 5 cases of osteoarthritis and 1 case of joint destruction consecutive to hemophilia. All patients were followed until fusion with an average follow-up of 12 months. The quality and position of the fusion were analyzed clinically and on radiograms. RESULTS: 9 patients obtained fusion in a neutral position and were able to walk with normal shoes. The average time to fusion was 14.5 weeks (8 to 40). 1 case failed and required reoperation after 15 months. No local complications were observed. DISCUSSION: Arthroscopic ankle fusion is a safe procedure with good results in cases with relatively little deformities. Its main interest lies in the low rate of complications. The technique does not increase the rate of fusion when compared to open technics. CONCLUSION: Arthroscopic fusion is recommended in cases with little to moderate deformities in the presence of poor wound healing factors.

Adult↗
PubMed1994

Tibial translation after anterior cruciate ligament rupture. Two radiological tests compared.

Anterior tibial translation was measured in both knees using the radiological Lachman test and the lateral monopodal stance tests in 281 patients with unilateral anterior cruciate ligament (ACL) rupture. Measurements of translation in the medial compartment were more useful than those in the lateral compartment. Measurement of anterior tibial translation in the medial compartment using the radiological Lachman test showed ACL rupture in 92% of cases compared with 70% for the lateral monopodal stance test. In normal and in ACL-ruptured knees the monopodal stance test showed that every 10 degrees increase in posterior inclination of the tibial plateau was associated with a 6 mm increase in anterior tibial translation; the radiological Lachman test showed a 3 mm increase for every 10 degrees increase in tibial slope.

Adolescent↗
PubMed1993

Estradiol modulation of GNRH-stimulated LH release in rat anterior pituitary cells: involvement of dihydropyridine-sensitive calcium channels.

Although enhancement of GnRH-stimulated luteinizing hormone (LH) release by estradiol (E2) has been established, it is not known at what stages of the process of transduction E2 acts. We investigated the release of LH in response to GnRH and to Bay K 8644, an activator of L-type calcium channels, in a culture of pituitary cells obtained from ovariectomized females, these cells having being treated or not with E2 (OVX + E2 and OVX). We studied the effects of D600, an antagonist of T- and L-type calcium channels, and PN 200-110, an antagonist of L-type calcium channels. The effects of the latter were studied in protein kinase C-depleted cells in order to investigate the possible phosphorylation of these channels. D600 caused a decrease in GnRH-stimulated LH release in OVX and OVX + E2 cells. However, this decrease was greater in OVX + E2 cells, suggesting that at least one type of calcium channels may be involved as a result of treatment with E2. We confirmed the involvement of L-type calcium channels in the action of GnRH since the GnRH-stimulated LH release was enhanced in the presence of Bay K 8644 in OVX cells. Bay K 8644 alone increased basal LH in a dose-dependent manner only in OVX + E2 cells. PN 200-110 induced a decrease of GnRH-stimulated LH release only in OVX + E2 cells. These results suggest that L-type calcium channels are activated in E2-treated cells. The dose-dependent decrease caused by PN 200-110 in OVX + E2 cells disappeared in the OVX + E2 PKC-depleted cells. This result was confirmed with Bay K 8644 and suggests a phosphorylation of dihydropyridine-sensitive calcium channels by protein kinase C.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Gonadotropin-releasing hormone-induced changes of intracellular pH in pituitary gonadotrophs: influence of estradiol.

Using the pH indicator, seminaphtorhodafluor, we studied the effects of GnRH on intracellular pH (pHi) in single gonadotroph cells, obtained from 3-week ovariectomized rats, treated or not with estradiol (E2) (OVX + E2, OVX). In a majority of cells (77.7% for OVX cells and 93.7% for OVX + E2 cells), GnRH induced acidification. A biphasic change of pHi, acidification followed by alkalinization, was observed in about 44% of the cells tested. In E2-treated cells, amplitude of acidification and duration of alkalinization were increased. Acidification and Ca2+ mobilization were related in time with a short delay (4-5 sec.). Depolarization with KCl and ionomycin, a Ca2+ ionophore, induced acidification. Taken together these observations suggest that acidification was caused by [Ca2+]i increase. When the Na+/H+ exchanger was blocked by amiloride or in Na(+)-free medium, GnRH-induced alkalinization was inhibited. Alkalinization disappeared completely when the cells were depleted in protein kinase C (PKC). Nevertheless, acute application of phorbol myristate acetate, known to activate PKC, was not sufficient to induce alkalinization. We conclude that PKC is necessary but not sufficient for alkalinization. In contrast, the GnRH response can be mimicked by a simultaneous application of phorbol myristate acetate and KCl. To further explore the putative role of pHi in the secretory process, LH release was studied. Using Na(+)-free medium or amiloride, we show that basal LH was not dependent upon the Na+/H+ exchanger activity. Conversely, GnRH-induced LH release was significantly decreased; this decrease was greater in E2-treated cells but prevented by bicarbonate. These data show that pHi and the Na+/H+ exchanger play an important role in the stimulus secretion coupling process of gonadotrophs. E2, which is an important factor in the regulation of gonadotropic hormone release, participates also in the pHi variations.

Amiloride↗
PubMed1992

Transient but not oscillating component of the calcium mobilizing response to gonadotropin-releasing hormone depends on calcium influx in pituitary gonadotrophs.

Gonadotropin-releasing hormone (GnRH)-stimulated changes in the cytosolic free Ca2+ concentration ([Ca2+]i) were studied in gonadotrophs cultured from 3-week ovariectomized rat pituitaries. One animal was used per cell preparation. [Ca2+]i was monitored in individual gonadotrophs by dual emission microspectrofluorimetry, using Indo-1 as the intracellular fluorescent Ca2+ probe. A short stimulation with GnRH evoked a complex concentration-dependent Ca2+ response in individual gonadotrophs. 0.1-1 nM GnRH triggered a series of sinusoidal-like [Ca2+]i oscillations superimposed upon a modest slow [Ca2+]i rise--the oscillating response mode--while 10-100 nM GnRH caused a biphasic increase in [Ca2+]i consisting of a monophasic transient and oscillations--the transient/oscillating response mode. Despite the consistency of Ca2+ responses, an inter-preparation heterogeneity of [Ca2+]i oscillations frequency was noticed. Moreover, we observed that, within a given cell preparation, the frequency of [Ca2+]i oscillations was independent of GnRH concentration whereas both peak [Ca2+]i and area under the [Ca2+]i versus time curve were concentration-dependent. Thus, in gonadotrophs, the presence of the GnRH signal would lead to [Ca2+]i oscillations, while the amplitude of the [Ca2+]i responses would code for the concentration of agonist. Both transient and oscillating components of GnRH responses depended on releasing activity of Ca(2+)-sequestering pools in as much as GnRH responses were unaffected by brief removal of external Ca2+, but suppressed by chelating intracellular free Ca2+ with BAPTA. However, prolonged exposure to a Ca(2+)-free medium suppressed the transient component while leaving the oscillating component unaffected. We therefore propose that gonadotrophs employ Ca(2+)-sequestering pools, whose maintenance depends on a slow Ca(2+)-entry, to give an amplitude-coded Ca2+ rise in response to a short GnRH stimulation.

Animals↗
PubMed1992

Identification and susceptibility testing for obligate anaerobic bacteria using a semi-automated API ATB plus system.

We evaluated the reliability of the API systems, Rapid ID 32 A and ATB ANA, for the identification and susceptibility testing of obligate anaerobic bacteria in a clinical laboratory that does not possess either an anaerobic chamber or a chromatograph. Tested were 105 clinical isolates. Identifications were compared with those obtained according to the criteria of the Virginia Polytechnic Institute Manual using the API 20 A system with incubation in an anaerobic chamber and gas chromatography. Identifications were concordant in 86.3% of cases. The Rapid ID 32 A system was inaccurate in distinguishing Bacteroides of the fragilis group. Susceptibility to 10 antibiotics of the ATB ANA system was compared to that obtained by MIC determination on Wilkins Chalgren agar. Overall, concordance was 78.2%. Disagreements were mostly minor (16.4%): resistant strains classified as intermediate or intermediate classified as susceptible. When the ATB ANA strip cannot be inoculated in an anaerobic chamber, it is possible that a denser inoculum would decrease the percentage of minor disagreements.

Anti-Bacterial Agents↗
PubMed1991

[Total hip prosthesis after high femoral osteotomy].

This study reviews a series of 75 total hip prosthesis (THP) after high femoral osteotomy operated on between 1968 and 1986. The mean delay between osteotomy and THP was 14 years. 53 prosthesis were available for long term follow-up with a mean follow up of 7 years. It was included in the category of total hip prosthesis operations considered as difficult. The lateral view is indispensable to plan the operation. Valgus intertrochanteric osteotomies and moderate internal translations posed no problems. Trochanteric osteotomy did not have to be systematic; it's inconveniences were not neglectible. It was reserved for isolated varizations for it modifies the axis of entry of the stem. The reamer was used in cases of narrowing of the femoral canal; notably after significant medializations. Derotation osteotomy was the last resort when it was impossible to position the stem secondary to a subtrochanteric osteotomy or significant angulation in the sagittal plane. An intertrochanteric osteotomy, when correctly realised, posed few problems during placement of a total hip prosthesis and licits a continued use in young subjects. Results of THP after intertrochanteric osteotomy compared well with primary THP, with 77.5 per cent good results and 15 per cent loosening. In addition to problems posed by etiologies (congenital dislocations), subtrochanteric osteotomies rendered cementing extremely difficult, even impossible. At long term, only 14.5 per cent of the results were good and the loosening rate was 45 per cent. Fortunately subtrochanteric osteotomies are practically abandoned.

Adolescent↗
PubMed1990

Estrogen modulated gonadotropin release in relation to gonadotropin-releasing-hormone (GnRH) and phorbol ester (PMA) actions in superfused rat pituitary cells.

The involvement of protein kinase C (PKC) in GnRH action is still a matter of controversy. We have conducted a comparative study of LH and FSH release in response to GnRH and to phorbol ester myristate acetate (PMA), an activator of PKC, by rat pituitary cells maintained in culture. The effect of E2 pretreatment coupled or not with PKC depletion was also studied. Different kinetics in the response of LH and FSH to GnRH were observed, suggesting that the intracellular pathways involved in the release process of the two hormones were somewhat different. Moreover, PMA (10 nM) stimulated LH release greatly and FSH release only slightly. Intracellular PKC depletion, obtained by a prolonged treatment (18 h) of the cells with PMA (1 microM), produced different results according to the endocrine status of the pituitary cells. GnRH (10 nM)-induced LH release was significantly decreased in PKC-depleted cells from proestrous females. For PKC-depleted cells from OVX females, it was decreased significantly only when cells had been pretreated by E2. These results suggest that the modulation of LH secretion by E2 involves PKC activation. FSH release was poorly stimulated by PMA; but, under any conditions, PKC depletion did not affect GnRH-induced FSH release.

Animals↗
PubMed1990

[Modulation of LH release by estradiol. Involvement of protein kinase C in the action mechanism of GnRH].

The involvement of PKC in GnRH action is still controversial. Discrepancies between different results could be due to the endocrine status of cells used for the studies. In order to determine a putative role for PKC in GnRH action and if gonadal steroids could be implicated in the PKC contribution to GnRH action, we have conducted a study of LH release in response to GnRH and to PMA, an activator of PKC, using an anterior pituitary cell culture system. The direct effects of E2 were considered coupled or not with the effect of PKC depletion. GnRH and PMA induced LH releases in a dose-dependent manner. Both are increased by E2. The PKC depletion had no effect on GnRH stimulated LH release in cells deprived of gonadal steroid influence but induced a significant decrease in cells which had been treated by E2. These results indicate that E2 alters cell sensitivity to GnRH by affecting post-receptor intracellular pathways such as PKC activation.

Animals↗
PubMed1990

[Total hip prosthesis in coxarthrosis following congenital hip dislocation (65 hips reviewed at 5 years)].

In 45 patients, 65 hips with CDH were given a THR after 5 years or more, with an average follow up of 8.5 years. The results and the technical problems are discussed. Of those 65 hips, there were 46 anterior dislocations, 15 intermediate dislocations and 4 cases of posterior dislocation. The mean shortening was 58.3 mm. In all cases, the authors performed a total arthroplasty on the original acetabulum, after lowering and reconstruction of the acetabulum by grafts taken from the femoral head. There are some immediate postoperative complications: 12 thromboembolic complications, hematomas and 2 cases of paralysis of the peroneal nerve. There was loosening in 8 patients (12%), with 3 infections. The functional results were good in 85% and poor in 7.5%. Nevertheless, the limp was maintained in 49 patients. There was residual low back pain in 7 patients. In 14% a second operation on the homolateral knee was performed after an average time of 2 years. The technical problems are discussed: the cup should be placed in the original acetabulum and in evaluating the lowering of the acetabulum, the condition of the lumbar spine should be considered. Posterior luxation is discussed as well; the authors recommend prudence in the indication for THR operations with lowering of the acetabulum shell.

Adult↗
PubMed1987

[Brachymetapodies: diagnostic and therapeutic aspects. Apropos of 3 cases].

The authors present 3 cases of brachymetapody (or "hereditary type E brachydactyly"). These conditions are defined by an abnormal shortness of some metacarpals and metatarsals, sometimes associated with other malformations and short stature. The feet may require a surgical correction with different alternatives, adapted to the type of malformations: lengthening of the short rays if they are the least numerous, shortening of one single "long" ray. Surgical indications depend upon pain, more than upon aesthetic considerations. In one of the reported cases, bilateral shortening osteotomy of the first metatarsal and proximal phalanx was performed.

Adolescent↗
PubMed1986

Long term management of hemorrhagic esophagitis with cimetidine and omeprazole.

We report a patient whose severe recurrent anemia was due to overt and occult hemorrhage from peptic esophagitis. Cimetidine treatment was successful for seven years but dose reduction was followed by intractable hemorrhage which did not respond to H2-receptor antagonists. Omeprazole therapy produced dramatic remission of symptoms and anemia.

Anemia↗
PubMed1986

[LHRH and LH release in the red fox Vulpes vulpes L].

Pituitary responsiveness to exogenous LHRH was studied in vivo and in vitro in the female red fox, a mono-oestrous species. In vivo, the ability of the pituitary to release LH in response to a single injection of LHRH (2 micrograms/kg) was determined at various stages of the reproductive cycle. The greatest responsiveness is observed during the preovulatory period, the lowest during the luteal phase. During the anoestrus phase, the responsiveness is reduced by more than 50% in lactating females compared to non lactating females. In vitro, dispersed fox anterior pituitary cells were exposed four times to LHRH (10(-9) M), hourly, for 8 min. Pituitary cells were taken from lactating and non lactating females. The cells are not sensitive to LHRH in lactating females but become more and more sensitive after weaning. It is suggested the inhibitory influence of lactation could be the result of prolactin-ovarian steroids-gonadotrophins interactions.

Animals↗