Biomedical subjects

J P Carreau

Publications and source records attributed to J P Carreau.

At least 19 recordsLinked to original sources

PubMed1999

Developmentally regulated changes in phospholipid composition in murine molar tooth.

In order to explore the possibility that phospholipids are differently expressed during the cascade of events leading to tooth formation, we decided to carry out simultaneous biochemical, histological and electron histochemical studies. High performance thin-layer chromatography and gas-liquid chromatography were used to compare the composition of embryonic mouse first molar tooth germs at day 18 of gestation (E18) and at birth (D1), erupting teeth at day 7 (D7) and erupted molars at day 21 (D21). For the latter, non-demineralized and EDTA-demineralized lipid extracts were analysed separately. Moreover, an ultrahistochemical study was carried out using the iodoplatinate reaction which retains and visualizes phospholipids. Developmentally regulated changes occurred and were closely correlated with an increase in cell membrane phospholipids. Gradual accumulation of phospholipids was identified in the extracellular matrix, at an early stage of tooth germ development within the basement membrane and later, as predentine/dentine and enamel components participating in mineralization processes. Matrix vesicles transiently present in dentine were partly responsible for the lipids that were detected. A first group of phospholipids including phosphatidylcholine as the major membrane-associated phospholipid and phosphatidylinositol as the intracellular second messenger increased by a factor of 2.3 between E18 and D21. This increase is probably associated with cell lengthening and was relatively modest compared with the higher increase detected for a second group of phospholipids, namely phosphatidylethanolamine (x4.8), phosphatidylserine (x 5.9) and sphingomyelin (x5.4). This second group of extracellular matrix-associated phospholipids constituted 68% of the demineralized lipid extract and, therefore, contributes to the mineralization of dental tissues.

Aging↗

PubMed1998

[Zona of the cranial nerves. Current aspects].

Recurrence of the chickenpox virus, herpes zoster localizes in cranial nerves in 30% of cases, with a predilection for the ophthalmic nerve. In young patients, clinicians must search for a herpes zoster-HIV association as well as oculomotor proprioception impairment in herpes zoster ophthalmicus. Enhanced MRI allows good objective view of the facial nerve lesions in herpes zoster facial paralysis. Finally, the gravity and aftereffects of cephalic herpes zoster can be decreased by an appropriate therapeutic approach.

AIDS-Related Opportunistic Infections↗

PubMed1997

In vitro culture of human dental pulp cells: some aspects of cells emerging early from the explant.

Cells emerging from a dental pulp explant were studied in order to elucidate the origin of precursor cells implicated in the formation of reparative dentin in vivo. Such cells observed at the very early stage of culture (days 5-10) were different from fibroblast-like cells obtained after one subculture. These early cells were round or elongated, with thin spinous processes, highly mobile, and contained numerous lipid vesicles. Incorporation of 1-[14C]palmitic acid did not show an increased incorporation of radiolabeled total lipids or triglycerides into these early cells compared to cells after four subcultures or control skin fibroblasts, suggesting that the lipids in vesicles were not synthesized by the cells. Since these cells also show a high level of fluid phase uptake via macropinocytosis, it is suggested that these lipids originate from macropinocytosis. Between days 10 and 20, these cells spontaneously start conversion into cells that have a fibroblast-like morphology, are less mobile, and lack lipid vesicles. Their morphology, movement, and macropinocytosis suggest that these cells, which migrate from the pulp explants, are mesenchymal cells related to mononuclear phagocytes/histiocytes.

Adolescent↗

PubMed1997

[Long-term complications of silicone implants used in the repair of fractures of the orbital floor].

A 15 patients series is presented concerning complications following the use of silicone orbital floor implants. The more frequent complications are inferior eyelid swelling, pain and ocular dystopia. Complications may occur very belatedly, 10 years for a patient, 9 years for an other. The mean delay from insertion to removal for complication of the implant is 4.3 years. Sinus troubles are found in 70% patients that may indicate a relationship between sinusal pathology and complications observed. The CT study is described. Precautions in insertion of the implant are given. Suggestions are done to prevent such complications.

Adolescent↗

PubMed1996

Extinction of peroxisomal functions in hepatoma cell-fibroblast hybrids.

Although peroxisomes are ubiquitous, differences in the number of organelles and in the expression of associated metabolic activities are observed, depending on the cell type. To investigate the control of peroxisomal activity in connection with cell differentiation, we constructed hybrids between two types of cells whose histogenetic origins dictate significant differences in peroxisomal activities: hepatoma cells and fibroblasts, with high and low expression, respectively, of peroxisomal functions. In these hybrids, extinction of the elevated activities that characterize liver cells is observed, in parallel with the well-documented extinction of differentiated functions. This suggests the existence in fibroblasts of a negative trans-acting regulation.

Acetyl-CoA C-Acetyltransferase↗

PubMed1996

[Hypoglossia-hypodactylia syndrome: apropos of a case with maxillo-mandibular synostosis, glossopalatine ankylosis and cleft palate].

BACKGROUND: The hypoglossia-hypodactylia syndrome, a combination of limb hypogenesis and micrognathia is exceptionally associated with glossopalatine ankylosis and cleft palate. CASE REPORT: A twin girl from monochorionic pregnancy had hypoglossia and micrognathia with anterior maxillo-mandibular fusion, glossopalatine ankylosis and cleft palate. Her left foot was amputated distal to the talus and calcaneous; her right foot had only one phallange. The second phallange of the second finger was hypoplastic on her right hand. There was no abnormality on left hand. Her sister was unaffected. The maxillo-mandibular fusion was divided on second day. The infant was able to suckle on the tenth day. Episodes of airway obstruction occurred on cardiorespiratory recording and the patient was further monitored at home. CONCLUSION: This case suggests that the hemodynamic disorders due to multiple vascular connections from monochorionic pregnancies may have induced ischemic lesions of hypoglossia-hypodactylia. Other malformations and signs of brain stem dysfunction should be detected.

Abnormalities, Multiple↗

PubMed1996

Radioautographic study of the incorporation of (3H)-choline into the phospholipids of secretory ameloblasts and enamel of normal and essential-fatty-acid-deficient rats.

(3H)-choline, a precursor for phosphatidylcholine (PC) and sphingomyelin (SM), was injected into rats killed after 4, 24, 48, and 96 hrs. Radioautography carried out on malachite-green/aldehyde-fixed tissues demonstrated that labeled choline was incorporated into cells and further released into the extracellular matrix. In predentin, labeling decreased rapidly, whereas in dentin, silver grains formed a stable band. In contrast, labeling was still high at 48 and 96 hrs in secretory ameloblasts as well as in the forming enamel. This indicates that ameloblasts are actively involved in the synthesis of membranes. Membrane remnants of the ameloblasts could be released into the forming enamel. In rats fed with an essential fatty-acid-deficient (EFAD) diet for 42 days, (3H)-choline uptake was delayed and reduced in pulp cells and odontoblasts, and consequently the migration of labeled phospholipids into dentin. The influence of the EFAD diet on secretory ameloblasts was limited. No difference was detected between normally fed and EFAD-fed rats in the forming enamel.

Ameloblasts↗

PubMed1996

[Proposal of a new topographic classification of mandibular fractures].

There has been a certain amount of confusion in publications concerning fractures of the mandible due to the lack of consensus on classification. Starting with the embryological, anatomic, biomechanical, pathogenic and epidemiological features of these fractures, we propose a new terminology and a new distribution of the units and subunits of the mandible in traumatology. The main point is to incorporate the angle subunit into the ramus unit.

Adult↗

PubMed1996

[The value of an osteosynthesis arch-plate combination in the application zone in the treatment of fractures of the body of the mandible].

Fractures of the tooth-bearing part of the mandibular body require both orthopedic stabilization of the maxillomandibular joint and surgical fixation. From an evaluation of the anatomic and biomechanical features of the mandible, we propose the notion of a useful zone for fixation. The useful zone is basically submitted to traction forces and includes both the teeth and the teeth-bearing bone situated above the mandibular canal in the body and the entire symphysis. Applying an arch-plate on the useful zone has the advantage of providing initial stability, progressive loading and reduction in risk of displacement or secondary infection. This therapeutic approach gives better results than simple plate fixation.

Adult↗

PubMed1996

[Mandibular condyle hyperplasia. Therapeutic review].

Excessive cartilage growth on the condyle process of the mandible can result from primary hyperreactivity of the growth cartilage or be a secondary adaptation to an imbalance in occlusive and/or cervicofacial conditions. Treatment depends on the distinction between these two forms. Primary active overgrowth is treated by condylectomy sparing the distal apparatus although conservative surgery to re-centering the temporomandibular joint and re-establish symmetry without condylectomy may be used in quiescent moderately active forms saving the joint. For secondary forms, the joint is re-centering and symmetry is re-established without condylectomy. If started early enough, orthopaedic treatment can avoid the development of secondary forms resulting an imbalance in occlusive and/or cervicofacial conditions.

Diagnosis, Differential↗

PubMed1996

[Melkersson-Rosenthal syndrome. Value of reduction cheiloplasty].

INTRODUCTION: The interest of cheiloplasty is not precisely defined in the treatment of Melkersson-Rosenthal syndrome (MRS). OBSERVATION: The case of a 32-year-old woman, suffering from a typical MRS is reported. The lack of efficacy of various classical molecules (corticoseroids, hydroxychloroquine, dapsone, colchicine, clofazimine) led to a surgical therapy, consisting in cheiloplasty. Systemic corticosteroids were associated. The result was good, with a follow-up of 2 years. COMMENTS: Cheiloplasty is essentially of cosmetical interest, in the MRS, once the inflammatory process has been stopped (almost one year). Medical treatment (corticosteroids), is to be continued after surgery, to avoid recurrence.

Adult↗

PubMed1995

Effects of essential fatty acid deficiency on rat molar pulp cells.

In rats fed an essential fatty acid deficient (EFAD) diet, either during pregnancy (DN) or for 4 wk postnatally (ND), the cell density in the central part of the pulp increased about two- and threefold, respectively, of that in rats who had received a conventional diet containing sunflower oil. Cells were especially numerous around capillaries. The cell density was also increased twofold in the subodontoblastic layer in the outer part of the pulp, cells being smaller in ND compared with DN. In contrast, the odontoblasts were reduced in height, and the Höhl cells formed a thin layer in EFAD rats. This emphasizes some aspects of pulp specificity which reacted differently from odontoblasts. We suggest that the function of killer cells which normally destroy cells at the periphery of the pulp may be impaired by the diet, leading to cell accumulation.

Animals↗

PubMed1995

Lipids in predentine and dentine.

Using two histochemical methods, malachite green-aldehyde and iodoplatinate, phospholipids were visualized in the predentine of rat incisors in the spaces located between collagen fibers and in dentine as needle-like structures located along individual or groups of mineralizing collagen fibers. The same staining pattern was seen with phospholipase A2-gold. Autoradiographic investigation using 3H choline as labelled precursor, visualized the incorporation of membrane-associated and extracellular choline-containing phosphatidyl choline and sphingomyelin. The cell and membrane-associated labelling decreased gradually between 24 and 4 days, whereas incorporation of the labelled precursor as stable extracellular matrix component was seen in dentine. In addition to these investigations, pharmacologically induced (suramine) and genetically (Krabbe's disease) lysosomal storage pathology was investigated. Defects due to lipid metabolism alterations were seen in predentine and/or in dentine. The major differences visualized here between the non-mineralized and mineralized compartments and interactions between phospholipids and proteoglycans, support the view that phospholipids as matrix components play an important role in the mechanisms of dentine formation and mineralization.

Animals↗

PubMed1995

[Palliative treatment of facial paralysis].

Facial nerve palsy disrupts both the static and dynamic equilibrium of the half-face involved. The imbalance worsens with age and senility further aggravates the situation. Palliative surgery can be used in complete intractable facial palsy or rarement for partial palsies or as a temporary treatment. The operation is proposed mostly for elderly patients and does not create other malformations or dysfunctions. Simple and effective reduction, cervicofacial lifting and plicature of the skin muscles is used with ocular protection (passive eyelid circle, lateral de-epidermalized skin flap, blepharorraphia) with or without use of locoregional tissues (orbito-naso-genial and labiogenial flaps) are usually sufficient.

Aged↗

PubMed1995

[The adipose tissue of the orbit. Anatomic classification, therapeutic deductions].

There are two types of adipose tissue in the orbit. The yellow fat and the more abundant white, or orbital fat. Orbital fat cannot be dissociated from the contents of the orbit and plays an important role in ocular physiology and oculomotricity. Orbital fat is essential for aesthetic orbits. Graves' disease and anophthalmia. Adipose tissue in the orbit is particularly important in protecting the ocular globe from lateral wall trauma.

Adipose Tissue↗

PubMed1994

Resistance to erucic acid as a selectable marker for peroxisomal activity: isolation of revertants of an infantile Refsum disease cell line.

A system based on the ability of cells to oxidize very long-chain fatty acids (VLCFA) was developed to select in vitro normal human fibroblasts from fibroblasts of patients suffering from peroxisomal disorders with multienzymatic deficiencies: Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease (IRD). Cells treated with various concentrations of erucic acid (C22:1 n-9) revealed an enhanced toxicity of this fatty acid for the fibroblasts of patients compared with normal cells. This differential toxicity is correlated with variable accumulations of C22:1 n-9 and the absence of beta-oxidation products in the mutants. Revertants from clonal IRD cell lines were isolated in the selective medium at frequencies ranging from 3 x 10(-7) to 4 x 10(-6) depending on the line. After six weeks of growth in the absence of selective pressure, the variants exhibited a resistance level to C22:1 n-9 identical to that of normal cells. Furthermore, beta-oxidation of VLCFA is re-established in these selected cells as well as dihydroxyacetone phosphate acyltransferase activity. Immunoblot experiments also demonstrated a restored pattern of acyl-CoA oxidase molecular forms. Last, immunofluorescence studies revealed the presence of cytoplasmic structures that were absent in the original IRD cells. Thus, both the deficiencies in metabolic pathways and paucity of the organelle are at least partially corrected in the selected clones.

Acyltransferases↗

PubMed1994

[Current surgical approach to masticatory system pain-dysfunction syndrome (except arthroscopy)].

The surgical treatment of SADAM concerns patients with irreversible lesions who continue to complain (disk displacement with pain and limited opening, painful arthrosis) after all the other therapeutic options have been unsuccessful and when no long-lasting improvement can be reasonable expected. Indications for surgery have declined with progress in aetiological treatment, particularly of occlusion, and arthroscopic treatment, but arthrotomy is the only remaining technique feasible in certain cases. SADAM should be a conservative surgery, protecting the disk (repositioning displaced disks, repairing perforated disks) and the articular surfaces (correcting bone irregularities). Anatomic and functional reconstruction of the joint cannot be successful unless the cause of the dysfunction is treated at the same time.

Arthroscopy↗

PubMed1991

Evidence against cytochrome b5 involvement in liver microsomal fatty acid elongation.

This study provides strong evidence against cytochrome b5 participation in the first reduction step-beta-ketoreduction-of rat liver microsomal fatty acid chain elongation. Several lines of evidence led to this conclusion: (a) beta-ketoreductase was not inducible by diet conditions since its activity was the same in microsomes from fasted rats and in rats fed a fat-free diet. Consequently, its activity was appreciable in microsomes from fasted rats. Nevertheless, cytochrome b5 reoxidation rate was not stimulated by adding beta-ketopalmitoyl-CoA to the latter microsomes. This suggests that it is not the activated beta-ketoreductase which stimulates the cytochrome b5 reoxidation rate, but another electron acceptor. (b) The delta 9-desaturase, present in microsomes from rats fed a fat-free diet, was totally inhibited by 4 mM KCN; beta-ketopalmitoyl-CoA or malonyl-CoA stimulated the reoxidation rate of cytochrome b5 but this increase was also inhibited by 4 mM KCN. This suggests that delta 9-desaturase is involved in the stimulation and shows that any inhibitor of delta 9-desaturase, including cytochrome b5 antibodies, may induce elongation inhibition. (c) NADH-dependent beta-ketoreductase activity was partially purified from Triton X-100 solubilised microsomes, in a fraction essentially free of cytochrome b5. Furthermore, when the fraction containing cytochrome b5 and NADH-cytochrome-b5 reductase was added to the fraction containing beta-ketoreductase activity, no increase in beta-ketoreductase activity was observed. Stearoyl-CoA desaturase activity which is also present in microsomes from rats fed a fat-free diet led to the results which have been misinterpreted in the conclusions of previous studies.

Alcohol Oxidoreductases↗