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Biomedical subjects

C Fontaine

Publications and source records attributed to C Fontaine.

At least 19 recordsLinked to original sources
PubMed2007

Relevance of the determination of serum-specific IgE antibodies in the diagnosis of immediate beta-lactam allergy.

BACKGROUND: Allergic reactions to beta-lactams are the most frequent cause of adverse drug reactions mediated by specific immunologic mechanisms. They can be explored by in vivo and/or in vitro tests. The measurement of serum-specific immunoglobulin E (IgE) presents several advantages: safety, simplicity, and availability to nonallergologist physicians. OBJECTIVES: To establish the diagnostic value of specific IgE determination in the diagnosis procedure of immediate beta-lactam allergy. METHODS: The in vitro determination of beta-lactam-specific IgE antibodies was compared in three well-defined groups of patients (n=45): one with negative skin tests and a positive drug provocation test, another with positive skin tests, and a third control exposed population with good tolerance. Two techniques were used: the CAP-FEIA system (Phadia) commercially available and a homemade radioallergosorbent test (RAST). RESULTS: The specificity of CAP-FEIA ranged from 83.3% to 100% and sensitivity from 0% to 25% depending on initial clinical manifestations. The specificity of RAST was between 66.7% and 83.3% and sensitivity 42.9% and 75%. In the subgroup of patients with an anaphylactic shock and negative skin tests, the sensitivity and specificity of RAST were 75%. Positive and negative predictive values were 45.5% and 77.1% with CAP-FEIA and 38.5% and 81.5% with RAST, respectively. CONCLUSION: These results indicate that, although the specificity of beta-lactam-specific IgE measurement is good, sensitivity is low. Immunoglobulin E measurement should be limited to patients with a clinical history of anaphylactic shock and negative skin tests in order to avoid a drug provocation test. More sensitive assays should be developed.

Adolescent↗
PubMed2006

Anatomic bases of vascularized elbow joint harvesting to achieve vascularized allograft.

In order to later make precise the operative technique of free vascularized elbow allograft transfer, the anatomic conditions necessary for the success of such an operation are reviewed. The exact topography of the nutrient foramina of the humerus, radius, and ulna has been specified on 102 dry bones. The osseous resection at the recipient will have to be carried out on these aspects: nutrient foramina of the three bones of the elbow (at 9 cm from medial epicondyle for the humerus; at 8 cm for the two bones of forearm) in order to preserve diaphysary vascularization of the recipient. A study of arterial and venous vascularization carried out on 18 anatomic specimens showed that the osseous ends were irrigated by a periosteal arterial network and were drained in the centromedullary cavities. Systematization of the arteriovenous blood supply of the distal end of the humerus and proximal ends of the two forearm bones is proposed after dissection of 18 anatomic specimens. Arterial periosteal territories are defined. The importance of each peri articular arteriole is estimated according to the surface of its respective section. A radial, constant, and musculoperiosteal collateral artery from the brachial artery is described. It accounts for 12% (+/- 3%) of the total contribution. The recurrent radial artery is the most significant: 31% (+/- 9%) of the total contribution. The profunda brachii artery is negligible: 4% (+/- 2%) of the total contribution. As well for vascular as mechanical reasons, osteosynthesis will have to be carried out using screwed plates, the optimal location of which is specified according to the arterial periosteal cartography. Ulnar and radial nerves and, to a lesser extent, the median nerve can be harvested "en bloc" preserving their vascular supply in order to make vascularized grafts of them. Free vascularized elbow allograft transfer is technically possible, if one respects these anatomic bases.

Arterioles↗
PubMed2006

IL-10 promoter and IL4-Ralpha gene SNPs are associated with immediate beta-lactam allergy in atopic women.

BACKGROUND: Allergic reactions to beta-lactam antibiotics represent the most frequent cause of immunological drug reactions. OBJECTIVE: This study evaluates the involvement of genetic susceptibility factors in patients with immediate allergic reactions to beta-lactams. We examined 15 single nucleotide polymorphisms (SNP) of genes coding proteins implicated in immunoglobulin (Ig)E synthesis regulation. METHODS: We performed a case-control study involving 44 patients with immediate beta-lactam allergy and 44 control subjects, all matched for sex and atopy. Interleukin (IL)-4, IL-13, IL-4Ralpha, signal transducer and activator of transcription 6 (STAT6), interferon (IFN)-gammaR1, IFN-gammaR2 and FcepsilonRIbeta gene polymorphisms were determined using polymerase chain reaction (PCR) restriction fragment length polymorphism, and IL-21R gene and IL-10 promoter polymorphisms by direct sequencing. RESULTS: Our analysis did not reveal differences in the distribution of the 15 SNPs between allergic patients and controls. However, among atopic subjects, we found two distinct significant associations between immediate beta-lactam allergy in women and the Ile75Val variant of IL-4Ralpha gene (P = 0.012, OR = 5.4, CI: 1.16-27.7), and two linked IL-10 promoter gene polymorphisms, -819C>T and -592 C>A (P = 0.023, OR = 17.5, CI: 1.26-533.07). In contrast, we observed no association in allergic male subjects in the atopic population. Interestingly, the IL-4Ralpha Ile75Val variant could have a paradoxal protective effect in atopic male patients (P = 0.004, OR = 0.07, CI: 0.01-0.66). CONCLUSION: Our findings suggest that polymorphisms in the IL-10 promoter and IL-4Ralpha genes are genetic factors that favour beta-lactam immediate allergies in female patients with atopy.

Adolescent↗
PubMed2005

Liver X receptor activation controls intracellular cholesterol trafficking and esterification in human macrophages.

Liver X receptors (LXRs) are nuclear receptors that regulate macrophage cholesterol efflux by inducing ATP-binding cassette transporter A1 (ABCA1) and ABCG1/ABCG4 gene expression. The Niemann-Pick C (NPC) proteins NPC1 and NPC2 are located in the late endosome, where they control cholesterol trafficking to the plasma membrane. The mobilization of cholesterol from intracellular pools to the plasma membrane is a determinant governing its availability for efflux to extracellular acceptors. Here we investigated the influence of LXR activation on intracellular cholesterol trafficking in primary human macrophages. Synthetic LXR activators increase the amount of free cholesterol in the plasma membrane by inducing NPC1 and NPC2 gene expression. Moreover, ABCA1-dependent cholesterol efflux induced by LXR activators was drastically decreased in the presence of progesterone, which blocks postlysosomal cholesterol trafficking, and reduced when NPC1 and NPC2 mRNA expression was depleted using small interfering RNA. The stimulation of cholesterol mobilization to the plasma membrane by LXRs led to a decrease in cholesteryl ester formation and Acyl-coenzyme A cholesterol acyltransferase-1 activity. These data indicate that LXR activation enhances cholesterol trafficking to the plasma membrane, where it becomes available for efflux, at the expense of esterification, thus contributing to the overall effects of LXR agonists in the control of macrophage cholesterol homeostasis.

ATP Binding Cassette Transporter 1↗
PubMed2005

Fibrates.

Atherosclerosis of the large arteries is the main origin of cerebro- and cardiovascular diseases, the leading causes of mortality and morbidity in industrialized countries. The pathophysiology of coronary and cerebrovascular atherosclerosis is multifactorial and complex. Fibrates are hypolipidemic drugs that lower progression of atherosclerotic lesions mainly through activation of the nuclear receptor peroxisome-proliferator activated receptor-alpha. In addition, fibrates exert pleiotropic and anti-inflammatory actions. In this chapter, we will focus on the different effects of fibrates impacting on the development of atherosclerosis.

Animals↗
PubMed2005

The role of the orphan nuclear receptor Rev-Erb alpha in adipocyte differentiation and function.

Lipid and carbohydrate homeostasis in higher organisms is governed by an integrated system that has a capacity to rapidly respond to metabolic changes. Numerous signals reciprocally convey information about body fat status from the periphery to central nervous system in the attempt to maintain body weight nearly stable throughout life. The role of adipocyte in energy homeostasis extends its function as a simple energy storage cell. Indeed, adipose tissue not only secretes fatty acids, but is also an active endocrine and paracrine organ due to the production of secreted proteins and lipid indicators collectively called adipokines. These observations have spurred interest in the identification of the transcriptional and other regulatory pathways of adipocyte differentiation. The nuclear receptor, peroxisome proliferator-activated receptor gamma (PPAR gamma) (NR1C3) and members of the CCAAT enhancer-binding protein (C/EBP) family are central mediators controlling adipocyte differentiation and function. Rev-erb alpha (NR1D1) is an orphan nuclear receptor encoded on the opposite strand of the thyroid receptor alpha gene. Rev-erb alpha acts as a negative regulator of transcription binding to the same response element than another orphan nuclear receptor, ROR alpha. Rev-erb alpha is highly expressed in adipose tissue, skeletal muscle, heart, liver and brain. Rev-erb alpha expression increases during adipocyte differentiation of 3T3-L1 cells and is induced by PPAR gamma activation in both 3T3-L1 cells in vitro and in rat adipose tissue in vivo via a direct repeat (DR2) in the Rev-erb alpha promoter. Ectopic expression of Rev-erb alpha potentiates the adipocyte differentiation in 3T3-L1 cells. Recent results in vascular smooth muscle cells (VSMCs) indicate that Rev-erb alpha also controls inflammation by regulating NF-kappa B responsive genes, such as IL-6 and COX-2. Future studies on a potential role of Rev-erb alpha on glucose homeostasis and/or inflammation control are thus warranted.

Adipocytes↗
PubMed2005

[Osteoma osteoid of the trapezoid bone: a case-report and review of the literature].

Osteoid osteomas are often localised in long bones but only rarely in the carpus. This is a case report of an osteoid osteoma in the trapezoid. Diagnosis was difficult and established late, due to misleading initial symptoms. Radiological examination allowed localisation of the nidus. For osteoid osteoma localised in a carpal bone, we recommend total removal without bone-graft or arthrodesis.

Adult↗
PubMed2005

[Scaphocapitate arthrodesis for chronic scapholunate instability: a retrospective study of 13 cases].

The management of chronic instability of the scapholunate joint is controversial. We have opted for scaphocapitate arthrodesis in such cases. The aim of this study was to analyse the clinical and radiological results of this procedure. Between 1997 and 2001, 13 scaphocapitate arthrodesis were performed for this indication. Eleven using two screws, one using a single screw plus a staple, and one using a single staple alone. The average age of the patients was 40 years. There were 8 sport accidents and 5 work accidents. The average follow-up was 26 months. We analysed the functional results and measured the height of the carpus and the radio-lunar angle radiographically. We noticed a mobility loss of between 20 and 40%, especially for radial tilt and flexion. The grip strength was improved. All the patients except one have some residual pain. We noted three non-unions which required revision with eventual final consolidation. The height of the carpus was improved. The average radio-lunar angle at follow-up was 16 degrees. Only one wrist remained in DISI. The mobility of the wrist was decreased by this procedure. In all these cases the dorsal approach to the wrist which we employed was bound to decrease the mobility. The radial tilt was decreased due to the partial arthrodesis. This procedure restore the height of the carpus and partially corrects the DISI. As we were not able to obtain a pain free wrist through our procedure, we raise the question as to whether a total neurectomy of the wrist should be performed at the same time.

Adult↗
PubMed2005

[Surgical anatomy of the dorsal face of the hand and the wrist].

The anatomical knowledge of the dorsal aspect of the hand has been enriched these last years by a more surgically applied approach, especially of that of its integument and blood supply. The vascularization of the superficial nerves, the anastomoses between the dorsal and palmar arterial networks has allowed designing new flaps, ante- and retrograde, usable in the coverage of more and more distal defects. The extensor apparatus shows many anatomic variations, often asymptomatic, except the extensor digitorum brevis manus muscle, which can mimic a mass at the dorsal aspect of the hand.

Blood Vessels↗
PubMed2005

[Long-term outcome of non-vascularized grafts for carpal scaphoid nonunion: 58 cases with 8.8 year follow-up].

PURPOSE OF THE STUDY: We conducted this retrospective study to analyze outcome obtained in 58 cases of carpal scaphoid nonunion treated with a non-vascularized corticocancellous graft. Our objective was to search for factors influencing outcome and identify appropriate indications. MATERIAL AND METHODS: Between 1984 and 1999, 103 patients were treated with a non-vascularized corticocancellous graft. Fifty-seven patients (58 wrists) were retained for analysis (4 deaths, 30 not attending follow-up consultation far from their residence, and 12 lost to follow-up). Mean follow-up was 106 months (range 19-212). Mean age was 36 years (20-62). Mean time to diagnosis of fracture was 35 months (6-252); the fracture was not recognized initially in 45 patients. According to the Schernberg classification, fractures were localized in zone II (n = 11), zone III (n = 40), and zone IV (n = 7). Using the Alnot classification, nonunion was grade I (n = 13), grade IIA (n = 20), grade IIB (n = 22), grade IIIA (n = 2), and grade IIIB (n = 1). Mean immobilization after grafting was 2.7 months. RESULTS: At three months, bone healing was achieved in 42 wrists. Thirty-six patients were very satisfied, 18 satisfied and four not satisfied. Twenty-seven patients presented significant pain at the graft harvesting site which regressed in all. There were no harvesting sequelae. Compared with the healthy wrist, we noted reduced flexion (8.7 degrees on average), extension (12.8 degrees on average), and radial inclination (10.5 degrees on average). Other wrist motions were not affected, particularly pronation and supination. The index of carpal height was 0.54 on average (range 0.47-0.57); carpal height was diminished in nine wrists. The radiolunate angle was 4.8 degrees on average (-17 degrees to +27 degrees). Dorsal intercalated segmental instability (DISI) was noted in twenty wrists. Bone healing was not achieved in eleven wrists, seven of which presented initial necrosis of the proximal pole. Pain improved in all patients. Persistence of DISI favored osteoarthritic degeneration. DISCUSSION: With this technique, we achieved bone healing in 81% of the cases. Non-vascularized grafting cannot provide cure in the event of advanced osteoarthrtic degeneration. Correction of DISI appears to be an indispensable element for the prevention of osteoarthritis. This technique should not be proposed for patients with a necrotic proximal pole, a vascularized graft would be preferable.

Adolescent↗
PubMed2004

The abductor pollicis longus: relation between innervation, muscle bellies and number of tendinous slips.

The aim of this study was to assess the relation between the insertions of the distal tendinous slips, the muscle bellies and the innervation pattern of the abductor pollicis longus (APL) muscle and of the extensor pollicis brevis (EPB). The upper extremities of 31 frozen cadavers were dissected under magnifying lenses to describe the distribution of the posterior interosseous nerve (PION). The number and the distribution of distal tendinous slip insertions of the APL muscle were variable. Two superficial and deep distal tendon groups were noted. The separation into superficial and deep muscular parts of the APL was frequent (87%). The EPB muscle was generally constituted by one muscle belly and one tendinous slip (93.5%). The innervation by the PION to the APL and EPB muscles was classified into five types. The specific innervation between superficial and deep muscular parts of the APL muscle, the specific innervation of the deep muscle bellies and the independence of the superficial and deep distal tendon groups of the APL muscle are arguments in favor of a complex functional role of the APL motor unit in thumb mechanics. However, no independence of the tendinous slips in the two distal tendon groups and no correlation between the number of tendinous slips and muscle bellies or innervation were observed. These limit the functional role of the two independent superficial and deep musculotendinous APL motor units. The use of the APL tendon for interposition arthroplasty, for tendon transfer or tendon translocation seems logical, particularly if using one of the two distal tendon groups.

Aged↗
PubMed2004

Intracarpal synovitis related to Dacron interposition after trapeziectomy: a report of three cases.

To prevent the mechanical consequences of trapeziectomy, interposition devices are promoted, such a Dacron spacer. We report three cases of osteolysis and synovitis related to the use of such a device. This phenomenon occurred 4 months after insertion and required revision surgery after 9 months of follow-up because of pain and extensive osteolysis of the carpal bones. Revision consisted of an extended synovectomy, removal of the broken Dacron followed by a ligamentoplasty using the Flexor Carpi Radialis. Two years after revision surgery the result was satisfactory, with no recurrence of pain or osteolysis. The Dacron device did not demonstrate improvement in clinical results after short-term follow-up when compared to conventional ligamentoplasty. We recommend cautious use of the Dacron device at trapeziectomy and attention must be paid to follow up of the patient.

Carpal Bones↗
PubMed2004

Genetic diversity of the shea tree (Vitellaria paradoxa C.F. Gaertn), detected by RAPD and chloroplast microsatellite markers.

RAPDs and chloroplast microsatellites were used to quantify the genetic variation of Vitellaria paradoxa (an economically important tree species in sub-Saharan Africa, north of the equator) and to analyse the geographic distribution of diversity in relation to the refuge theory. A total of 13 locations were sampled in eight countries, covering most of the natural range from Senegal to Uganda. A total of 67 polymorphic and 15 monomorphic RAPD loci were detected in 179 individuals. No relationship was identified between diversity and longitude or latitude. An unrooted neighbour-joining tree suggested a western group and an eastern group, representing 7% (P = 0.000) of the total variation. A Mantel test suggested that genetic distances between populations were correlated to geographic distances (R = 0.88, P = 0.001). The three-chloroplast microsatellite primers, assayed in 116 individuals, revealed 10 different alleles and seven chlorotypes. Most of the populations comprised a single haplotype. It is proposed from these results that the difference between western and eastern populations results from putative refugia separated by the current 'Dahomey Gap' (a semiarid zone that meets the coast around the Ghana-Togo-Benin-Nigeria borders), an area that may have been exceptionally dry during glacial periods. In addition, it is suggested that the haplotype distribution and frequency in the western populations could be due to the more recent impact of humans, particularly shea tree selection and dispersal during traditional agroforestry.

Chloroplasts↗
PubMed2004

Inhibition of both Trypanosoma brucei bloodstream form and related glycolytic enzymes by a new kolavic acid derivative isolated from Entada abyssinica.

A new kolavic acid derivative known from spectroscopic analyses as monomethyl ester-15-kolavic acid was isolated from the stem bark of Entada abyssinica, a plant traditionally used in West and East Africa for the management of sleeping sickness. The new derivative showed a strong and selective inhibitory activity on the GAPDH enzyme of Trypanosoma brucei with an IC50 value of 0.012 mM.

Animals↗
PubMed2003

Concurrent aberrant right gastric vein directly draining into the liver and variations of the hepatic artery.

We report an autopsy on a 46-year-old man, a case that presented the concurrence of two rare vascular variations of the lesser omentum: aberrant right gastric vein draining directly into the liver, and multiple hepatic arteries. Although the left gastric vein emptied into the left aspect of the portal vein, the right one was found to ascend from the gastric lesser curvature along the right aspect of the common bile duct and to reach directly the porta hepatis. A left hepatic artery originating from the left gastric artery entered the porta hepatis in conjunction with the left ramus of the portal vein. A predominant right hepatic artery arose from the superior mesenteric artery and entered the porta hepatis in conjunction with the right ramus of the portal vein. The proper hepatic artery originating from the celiac artery entered the porta hepatis in conjunction with the aberrant right gastric vein. The possibility of a common underlying mechanism for these rare vascular variations is discussed.

Abnormalities, Multiple↗