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Biomedical subjects

P Mercier

Publications and source records attributed to P Mercier.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Evaluation of transfusion strategies during craniosynostosis repairs].

OBJECTIVE: To evaluate the changes in transfusion practices during craniosynostosis surgery in children, with consideration of the transfusion-associated risks. STUDY DESIGN: Retrospective study. PATIENTS: The study included 64 consecutive craniosynostosis repairs by the same neurosurgical and anaesthetic team, over a period of 17 years. METHODS: The children were allocated into two groups. In group I (1980-1991), blood loss was compensated precisely from scalp incision on. In group II (1992-1996), transfusion was only started when blood loss crossed a calculated limit considered as acceptable. The mean criterion of judgment was the quantity of transfused blood in comparison with the theoretical blood volume. Mean preoperative and postoperative haemoglobin concentrations, estimated blood losses, volume of replaced blood and number of transfused patients were compared between the two groups with a two tailed Student's t test. RESULTS: The rate of non transfused children increased from 6% before 1991 to 39% after 1992%; conservely the rate of postoperative transfusions increased from 3 to 39%. CONCLUSION: The risks of blood transfusion favoured the development of new of more restrictive transfusion practices, even in haemorrhagic surgery. To limit blood transfusion in craniosynostosis surgery, a harmonious cooperation between surgeons and anaesthetists is essential and blood replacement must be based on a definite determination of the acceptable blood losses.

Blood Loss, Surgical↗
PubMed2000

lacZ sequences prevent regulated expression of housekeeping genes.

In order to dissect the MHC class I H-2K gene regulatory sequences, we p reviously generated transgenic mice containing various H-2K/lacZ fusion genes. However contrary to transgenes where H-2K sequences were fused to other coding sequences, none of the lacZ fusion transgenes was widely ex pressed like H-2K gene. We now show that this silencing also occurs when lacZ is inserted into a larger H-2K genomic construct including promoter and other regulatory elements. Because the 5'H-2K region contains a CpG island, we suspected that the presence of lacZ coding sequences was inte rfering with the mechanism by which the H-2K promoter region is normally unmethylated and transcriptionally active. Indeed, we show that in high ( >10) copy number transgenic mice, insertion of lacZ sequences in the v icinity of the H-2K promoter results in partial or complete methylation of the H-2K CpG island. However, in low (1-3) copy number transgenic mic e no methylation was observed but the transgene was still silent, sugges ting that the silencing effect of lacZ does not only rely on abnormal CpG methylation. Intriguingly, when the H -2/lacZ construct was introduced via embryonic stem (ES) cells, regulate d transgene expression was observed in several chimaeric embryos derived from independent ES clones, but never in adult chimeras. Combined with t he fact that, despite much effort, it has been very difficult to generat e 'blue' mice, our results highlight the transcription-silencing effect of lacZ sequences when they are associated with regulatory sequences of ubiquitously expressed genes.

5' Untranslated Regions↗
PubMed2000

[Incidence of grasping and its relationship to cerebral lesions].

Grasping is associated with frontal lobe pathology. Nevertheless, there is lack of precise anatomical correlations and very few studies are published. The aim of the study was to determine the incidence of the grasping and its relationship to cerebral lesions. We studied 236 patients admitted to the Neurology Department (108 women and 128 men; mean age 65.3), and tested with a standardized procedure (De Renzi and Barbieri, 1992). A score of grasping was determined for each patient. The locations of the cerebral lesions were assessed by two neurologists using the method of Damasio and Damasio (1989). Grasping was found in 38 patients (16.1p.100) with dementia or cerebral damage. In all cases, the lesion affected the frontal lobe. The patients with grasping showed a significant higher number of lesioned areas particularly for the frontal and the parietal regions. The score of right grasping was significantly higher with a lesion in the right paraventricular frontal and in the left parietal paraventricular areas. The score of left grasping was significantly higher with a lesion in the left frontal paraventricular area. These results are discussed in relationship with motor control.

Age Factors↗
PubMed1999

Local and sustained delivery of 5-fluorouracil from biodegradable microspheres for the radiosensitization of glioblastoma: a pilot study.

BACKGROUND: The authors have developed a new method of drug delivery into the brain using implantable biodegradable microspheres. In this study, this method was used to provide localized and sustained delivery of 5-fluorouracil (5-FU) after the surgical resection of glioblastoma. This antimetabolite and radiosensitizing drug was selected in an attempt to decrease the rate of local recurrence of the tumor. METHODS: Eight patients with newly diagnosed glioblastoma were included in the study and 2 increasing amounts of 5-FU were studied (70 mg and 132 mg). After surgical resection of the tumor, poly(D-L lactide-co-glycolide) 5-FU-loaded microspheres with an average dimension of 45 microm were implanted in the wall of the surgical bed. External beam radiation (59.4 grays) was initiated before the seventh postsurgical day. Patients were followed by clinical examination, magnetic resonance imaging, and 5-FU assays in the blood and cerebrospinal fluid (CSF). RESULTS: 5-FU assays confirmed sustained concentrations in the CSF for at least 1 month. Concentrations of 5-FU in the blood were lower and transitory. Systemic tolerance to the treatment was good; one case of recurrent brain swelling was observed at the higher dose studied. At the time of last follow-up the overall median survival time was 98 weeks from the time of implantation and 2 patients had achieved disease remission at 139 and 153 weeks, respectively. CONCLUSIONS: This study demonstrates that biodegradable microspheres are efficient systems for drug delivery into the brain and may have future application in the treatment of brain tumors. Further studies are needed to confirm the potential of 5-FU-loaded microspheres for the radiosensitization of glioblastoma. [Please see editorial on pages 197-9, this issue].

Adolescent↗
PubMed1999

Arterial supply of the duodenal bulb: an anatomoclinical study.

An anatomic and radio-anatomic study of 15 specimens enabled us to reconsider the arterial vascularization of the duodenal bulb and to propose a new classification based on anatomoclinical criteria. The two arterial pedicles (infra- and supraduodenal) reach the bulb on its posterior aspect; each pedicle is made up of two sorts of blood currents (right and left); the posterior aspect of the bulb seems to be the most vascularized one, explaining, apart from bleeding from gastroduodenal a. erosion, the hemorrhagic character of ulcers of the posterior aspect of the bulb. The predominance of the left-hand currents explains the possible ischemia of the duodenal bulb and/or rupture of the duodenal stump after their interruption.

Aged↗
PubMed1999

High and low lateral approaches to the popliteal artery.

Using a series of 20 dissections and two anatomic transverse sections of a lower limb, the authors investigated the lateral approaches to the popliteal artery. The high lateral approach (above the knee) is not very aggressive and gives access to the retro-genicular part of the popliteal artery. After cutaneous and fascial incision, a simple gap between the vastus lateralis and biceps femoris mm. allows easy exposure of the popliteal vessels after backward retraction of the sciatic nerve. The low lateral approach to the artery (below the knee) is very aggressive for the vessels, nerves, and ligaments of the area. It involves the resection of the upper fourth of the fibula and the isolation and protection of the common peroneal nerve Nevertheless, these lateral approaches must be known and used when classic approaches (medial and posterior) are impossible.

Dermatologic Surgical Procedures↗
PubMed1999

Descriptive anatomic study of the fourth perforating artery of the femoral system.

The existence of the fourth perforating artery of Paturet [7], a collateral branch of the superficial femoral artery in its lower third, is the subject of much debate. This artery has so far only been the subject of radio-anatomic descriptions based on arteriographies carried out within the context of arteriopathy of the lower limbs. We present a descriptive anatomic study of this artery based on 14 observations on 32 dissections. Three types of approach were carried out: exposure of the artery of the femoral quadriceps muscle up to its ending in the vastus lateralis; a lateral "orthopaedic" approach to the lower third of the femur; and a "vascular" approach by a medial incision to the femoro-popliteal axis in the lower third of the thigh. Its main relations are described, passing in front of the superficial femoral vein and then behind the femur before ending at the vastus lateralis muscle. These relations explain the possibility of anastomoses with collateral or terminal branches of the deep femoral artery (vastus lateralis artery, third perforating artery). The fourth perforating artery of Paturet [7] must be protected in traumatologic and vascular surgery. It is the main collector of vascular anastomoses between the deep femoral artery and the femoro-popliteal axis in the event of proximal occlusion of the superficial femoral artery. Its removal, in such a case, can aggravate an underlying arteriopathy.

Aged↗
PubMed1999

Anatomic and radioanatomic study of the lateral genicular arteries: application to prevention of postoperative hemarthrosis after arthroscopic lateral retinacular release.

Arthroscopic lateral retinacular release can be complicated by hemarthrosis in 10 to 18% of cases. The vascular structures involved are the lateral vascular pedicles of the knee. This study examines the topography of these pedicles. Anatomic and radioanatomic studies carried out in 50 specimens defined the route of the vascular pedicles at the lateral aspect of the knee. From the measurements carried out, we noted the relative homogeneity of the routes taken by the different proximo-lateral vascular pedicles, which are highly vulnerable, and the variability of the disto-lateral arterial routes. A tracing-paper study identified two distinct routes for the disto-lateral vascular pedicle and evaluated the risk of injury to it in surgical approaches to the lateral aspect of the knee. Finally, the topographic data of the study suggest the possibility of preventive hemostasis of the proximo-lateral pedicle via a minimal approach close to the patella. Furthermore, it seems possible to avoid cutting the disto-lateral pedicle if it is localised by cutaneous trans-illumination at the beginning of the operation.

Arthroscopy↗
PubMed1999

Persistent sciatic artery: report of an original aneurysm-associated case.

Persistent sciatic artery (PSA) is a rare embryologic abnormality and can sometimes be bilateral. It may be discovered because of a gluteal aneurysm or ischemic or embolic complications in the lower limb. The case we report was a unilateral type III aneurysm-associated PSA. Since the abnormal artery may be the only source of blood supply to the lower limb, a thorough knowledge of the artery and its embryologic origins is essential.

Adult↗
PubMed1999

Dermal sinus and intramedullary spinal cord abscess. Report of two cases and review of the literature.

Intramedullary abscesses of the spinal cord are uncommon. Most of them occur in association with heart, pulmonary or urogenital infections. We report two cases of intramedullary spinal cord abscesses secondary to congenital dermal sinus. Only 14 cases of such an association have previously been reported. In our cases, dermal sinus was associated with an epidermoid tumour. The clinical presentation, pathogenesis, magnetic resonance imaging findings, surgical management and outcome are discussed.

Abscess↗
PubMed1999

Ventral transdural herniation of the thoracic spinal cord: surgical treatment in four cases and review of literature.

BACKGROUND: A specific cause of progressive Brown-Sequard syndrome has been identified: a ventral herniation of the thoracic spinal cord through the dural sleeve on one side. METHOD: Four female patients who were affected by a progressive Brown Sequard syndrome related to a transdural spinal cord herniation have been investigated and were submitted to surgery and postoperative evaluation. FINDINGS: The MRI scan showed atrophy and forward displacement of the spinal cord on one side and adhesion of the spinal cord to the dura mater. CT myelography demonstrated the disappearance of the premedullar rim at the level of the herniation and the shadow of the extradural herniation. Surgical treatment consisted in the excision of the arachnoid cyst when there was one, section of the dentate ligament, release of the adhesions, detachment of the spinal cord from the hernial orifice, and lastly suture of the dural tear or placement by a patch. Follow-up examination showed motor improvement with persistent sensory deficit in two cases and stabilisation in two cases. INTERPRETATION: The cause of the dural tear, either traumatic or congenital could not be confirmed in the four cases. Symptoms probably occur when herniation fills the orifice and strangulation happens which explains the late appearance and progressive evolution of this myelopathy. Mobilisation of the herniated spinal cord back into the intradural space can be achieved by surgery and may stop the evolution of the symptoms and signs.

Adult↗
PubMed1999

HLA DRB1, DMA, and DMB gene polymorphisms in rheumatoid arthritis.

OBJECTIVE: To study the influence of DMA and DMB genes on susceptibility to Rheumatoid Arthritis (RA). METHODS: HLA-DRB1, DMA and DMB polymorphisms were defined by PCR SSOP in 203 European Mediterranean RA patients and 181 unrelated healthy controls. RESULTS: No significant difference in the phenotype frequencies of DMA and DMB alleles was observed between patients and controls. We found decreased frequencies of DMA*0102 and DMB*0104 in patients but this did not reach significance. These decreased frequencies could be due to a positive linkage disequilibrium with DRB1*0701, an allele which is underrepresented in RA patients. In stratified analysis with RA susceptibility Epitope positive (SE) DRB1 alleles, there was no significant difference in DMA and DMB phenotype frequencies between SE/SE, SE/X, and X/X patients versus controls. Among SE/X subjects, no significant difference in DM distribution frequencies was observed in DRB1*0101/X, 0102/X, 0401/X, 0404/X and 0405/X groups. CONCLUSION: DMA and DMB polymorphism does not seem to influence susceptibility to develop RA. Differences in DMA phenotype frequencies between patients and controls are secondary to linkage disequilibrium with DRB1 alleles.

Adult↗
PubMed1999

A "case control" study on the rôle of HLA DR4 in severe periodontitis and rapidly progressive periodontitis. Identification of types and subtypes using molecular biology (PCR.SSO).

HLA DR4 antigens have been considered as a risk factor in periodontal disease. The aim of this "case control" study was to verify and to provide fuller clarification of such data. "Cases" or patients had to be aged between 20 and 48 years. They presented at least 5 sites spread over several teeth with an attachment loss equal or greater than 6 mm, and 10 sites spread over several teeth with periodontal pockets equal to or greater than 5 mm. Verification with a WHO probe showed an individual CPITN score of 4. Moreover, subjects whose average CPITN score for the 6 sextants was less than 3 were excluded from the study. Among these "severe periodontitis" patients, a subgroup was distinguished composed of subjects aged 20-35 years who presented, in accordance with the cases by Katz and co-workers, 5 or more teeth showing pocket depths of 6 mm or more. The dental chartings of these subjects showed an attachment loss of more than 3 mm on certain teeth over an inter-exam period of 1-3 years. They all displayed obvious loss of bony support in the affected sites. This constituted the "rapidly progressive periodontitis" subgroup. The "controls" were all over 20 years of age, and it was clinically verified that they were free of periodontal disease. There were 48 "cases" and 55 "controls". HLA typing of patients and controls was performed using "sequence oligoprobe hybridization after polymerase chain reaction" in accordance with the 11th International Workshop. This method allowed the detection of DR4 alleles as well as DR4 subtypes. The ethno-geographic origin of the subjects, considered as a confounding variable, was neutralized by stratified analysis. Subtypes 0401, 0404, 0405 and 0408 tended to be more frequent (p=0.08) in the cases (Severe Periodontitis). Focusing on analysis of "rapidly progressive periodontitis" in subjects aged 20-35 years, a very significant Mantel-Haenszel chi2 was obtained (p=0.0058) which led to a Mantel-Haenszel standardized odds ratio (OR) equal to 17. The 95% confidence interval was 1.03<0.R.<180.10. In conclusion, this supports previous reports and gives further clarification: in particular subtypes 0401, 0404, 0405 and 0408 can be considered as a risk factor for "rapidly progressive periodontitis". It should be noted that these determinants have been implicated in rheumatoid arthritis.

Adult↗
PubMed1999

Relationship between HLA-DQ and -DR genotypes and clinical characteristics in a French population of Type 1 diabetic patients.

AIMS: The present study was designed to look for a heterogeneity in the association between Type 1 diabetes mellitus (DM) and class II alleles of major histocompatibility complex (MHC) according to clinical presentation and C-peptide secretion during the first year of the disease, in a population living in south of France. METHODS: HLA DRB1 and DQB1 genotypes were determined in 129 Caucasoid patients with Type 1 DM and compared to a control group (n = 88). In a subgroup of 46 young adult diabetic patients, basal and postglucagon C-peptide secretion was followed during the first year of the disease (at 0, 1, 3, 6, 9 and 12 months). RESULTS: The two main haplotypes associated with Type 1 DM were DRB1*04DQB1*0302 and DRB1*03DQB1*02. The genotypes DRB1* 04DQB1 *0302/DRB1*04DQB1*0302 and DRB1 *03DQB1*02/DRB1*04DQB1* 0302 were associated with an early onset of diabetes, while homozygosity for DRB1*03DQB1*02 was characterized by later onset. Levels of residual insulin secretion in patients genotyped DRB1*03DQA1*0501DQB1* 02/DRB1* 04DQA1*0301DQB1*0302 were higher than in patients genotyped DRB1* 3DQA1*0501DQB1*02/DRB1*XDQA1*XDQB1*X or DRB1* XDQA1* XDQB1*X/DRB1*XDQA1*XDQB1*X. CONCLUSIONS: This study confirms some clinical heterogeneity of Type 1 DM linked to HLA DR and DQ genotypes, and leads to a paradoxical finding: DQB1*02/ DQB1*0302 combination predisposes to an early onset in the whole population but residual secretion of insulin disappears more slowly in a subgroup of young adults with recently diagnosed diabetes. These data suggest that interrelations between MHC genotype and diabetogenic process could be different at various ages of life.

Adolescent↗
PubMed1999

Subclavian steal syndrome and flow-related aneurysm. Another reason to treat.

A 48-year-old woman presented with a symptomatic right subclavian steal syndrome due to proximal subclavian artery stenosis. Anatomically the innominate artery was absent. Collateral circulation followed the vertebro-vertebral pathway with reversal of blood flow in the ipsilateral vertebral artery. There was also multiple dilated intervertebral collaterals and an associated saccular aneurysm on one of them. Surgical carotid-subclavian transposition permitted relief of clinical symptoms, disappearance of collateral circulation and subtotal regression of the aneurysm. This spontaneous evolution confirmed the role of high-flow in the pathogenesis of some aneurysms and the habitually good prognosis of flow-related aneurysms with correction of the cause. Arteriography still appears essential in diagnosis, pretherapeutic assessment and sometimes post-treatment evaluation in subclavian steal syndrome.

Aneurysm↗
PubMed1999

Low incidence of severe adverse effects after mandibular ridge reconstruction using hydroxylapatite.

The short and long term adverse effects after ridge reconstruction using hydroxylapatite (HA) are presented in this study. The HA was inserted using a modified tunnelling technique, followed by a lowering of the floor of the mouth and a vestibuloplasty using split thickness skin graft, 4-6 weeks later. The study comprised 637 patients followed for a period of 1 to 10 years (mean 6.0+/-2.6 years). Major loss of HA was seen in 17 patients (2.7%). Donor site visibility (skin graft) appeared to improve greatly over the years from 29.2% to 8.8% at the latest follow-up. Neurosurgery deficits also improved from 11.6% (paraesthesia and dysaesthesia) to 4.6%. Long term follow-up revealed a high percentage of patient satisfaction (97%), indicating that the low incidence of severe adverse effects of the procedure does play a significant role in the appreciation of the procedure and prosthetic care.

Adult↗
PubMed1999

[The lumbar vein at L2 and the reno-azygo-lumbar arch: anatomic and radiologic studies].

The lumbar vein at L2 was described by C. Gillot and B. Singer (1974). On the right side, after drawing off the 12th intercostal vein, it forms the lateral root of the azygos vein. Its way is as a frame, transverse going along the body of the 2nd lumbar vertebra, then upward along the spine after having integrated the veins of the L2-L3 intervertebral foramen. In its typical form, the vein is at L2 but it can be at L1 or L3. It takes the name of lateral root of the azygos vein only after receiving the 12th intercostal vein. Because of its diameter (5 mm), it forms a cavo-caval anastomosis via the azygos vein. The renal azygo-lumbar arch of Lejars is the equivalent on the left side of the right vein at L2. This arch contributes to the formation of the lateral root of the hemi-azygos vein. The right vein at L2 and the reno-azygo-lumbar arch were studied by dissections and by radiologic protocols. The radiologic studies (CT, MRI, 3D reconstructions) were carried out after injections of gelatin-gadolinium-minimum and altufix-minimum mixtures. The results showed the numerous variations of origin of the azygos system. The use of multiple and complementary technics are very helpful to describe these variations.

Azygos Vein↗