PubMed Health⌕ Search

Biomedical subjects

J Nicolas

Publications and source records attributed to J Nicolas.

At least 19 recordsLinked to original sources
PubMed2006

Platysma suspension and platysmaplasty during neck lift: anatomical study and analysis of 30 cases.

BACKGROUND: The authors developed a technique for the treatment of the cervical area during face lifts. The authors called this technique platysma suspension and platysmaplasty rather than plication. METHODS: After an anatomical study on 10 corpses on which the authors tested the various platysma suspension techniques, they carried out platysma suspension associated with platysmaplasty in 30 patients. RESULTS: This technique consists of suspending the free edge of the platysma muscle and fixing it to a resistant tissue close to the earlobe (Loré's fascia or tympanoparotid fascia). The anterior triangle of the neck was well defined, and there was no need to undermine the platysma muscle because of a perfect sliding plane between the platysma and sternocleidomastoid muscles. CONCLUSIONS: This technique is both simple and effective. It generates long-lasting results, without the inconveniences or complications associated with other techniques.

Aged↗
PubMed2005

[Quality of life in HIV-infected children and adolescents under highly active antiretroviral therapy: change over time, effects of age and familial context].

OBJECTIVE: To evaluate Quality of life (QoL) of HIV-infected children under highly active antiretroviral therapies, and its change over 18 months. MATERIALS AND METHODS: QoL was evaluated by self-administred questionnaires (french versions of AUQUEI, OK-ado, and compilation of both) in 23 young living with HIV/AIDS (6-15 yrs), under antiretroviral multitherapies, and re-evaluated 18 months later in 19 of them. RESULTS: At baseline, QoL in HIV-infected children-adolescents was relatively good. The answers given to each items and the mean score from infected children were similar to those obtained in uninfected healthy children. Moreover, infected adolescents distinguished definitly from healthy adolescents, describing higher QoL. The mean satisfaction score from the whole group decreased between M0 and M18 (mainly in the youngests), and mainly concerned 3 fields (self-esteem, health and school) while their somatic health remained stable or improved. An effect of the familial context was also observed for these 3 fields. CONCLUSION: The progressive decline of QoL in HIV-infected children, and the surprising high and steady level of satisfaction over-time provided by the adolescents, underlined the frailty of this population and the need for a psychologic management associated to the medical follow-up. Such a multidisciplinary approach should take into account the preoccupations and difficulties of each age-class, those linked to the diagnosis itself, and to the familial or scolar contexts, in order to preserve QoL of this pediatric population, as far as possible, in a long term.

Adolescent↗
PubMed2005

Estimation of odor emission rate from landfill areas using the sniffing team method.

The monitoring of the odor annoyance generated by a landfill area is difficult, since it is a multi-area-sources problem, with a discontinuous odor emission. This paper proposes an adaptation of the method of sniffing team campaigns to the particular case of fresh waste odors. The method is based on the field determination of odor perception points, followed by data processing with a bi-Gaussian-type model, adapted to handle the odors. In a first step, field observers delineate the region in which odor impact is experienced and then the emission rate is manipulated in a dispersion model until the predicted size of the impact zone matches that observed in the field. In a second step the adjusted emission rate is entered into the model to calculate the percentiles corresponding to the average annoyance zone. The originality of the proposed method is the introduction of all observation points and of all recorded meteorological data into the model. The paper discusses the method limitations and the errors induced on the results, i.e. the odor emission rate and the percentile lines (or iso-concentration lines) which are used to describe the odor concentrations on a map of the surroundings of the plant. The proposed method proves to be reliable for diffuse sources, such as landfill areas. The obtained results are coherent with other results found in the literature with other techniques.

Air Movements↗
PubMed2005

[Detection of the sentinal node in squamous-cell carcinoma of the oral cavity and oropharynx. Preliminary study].

INTRODUCTION: The sentinel lymph node is defined as the first relay of the lymphatic drainage of the tumor. Isotopic detection of the sentinel lymph node and absence of its metastatic invasion should theoretically be predictive of total drainage of the tumor. The goal of this study was to evaluate sentinel lymph node detectability by lymphoscintigraphy in N0 and/or N1 squamous-cell carcinoma of oral cavity and oropharynx and to determine its negative predictive value. MATERIAL AND METHOD: Lymphoscintigraphy was used for sentinel lymph node detection. The procedure required peritumoral injection of technicium-labeled colloids to enable anatomical and cutaneous location of the sentinel lymph node. A one-way Tyco-Mallinckrodt probe was used for intraoperative detection of the sentinel lymph node. This prospective study included 21 patients with N0 or N1 squamous-cell carcinoma of the oral cavity and the oropharynx. The surgical attitude based on T and N was not modified in this prospective study without direct individual benefit for the patient. Neck dissection was achieved without difficulty. RESULTS: The sentinel lymph node was identified in 20 out of 21 subjects. The sentinel lymph node was not identified in one patient with recurrence T2N0M0 squamous-cell carcinoma of the oropharynx radiated 3 years earlier. The percentage of false-negatives was 12.5% (1 false-negative out of 8 positive patients), giving a sensibility of the detection method of 87.5% (IC (95%)=[47.35-99.68]). This false-negative patient had a T3N0M0 squamous-cell carcinoma of the oropharynx with a sentinel lymph node removed in territory III. Neck dissection revealed 1 N + R- in the sub-mandibular territory associated with 27 N-R-. The probability of not finding a metastatic node at neck dissection when the sentinel lymph node is not metastatic (negative predictive value) was 92.3% (12/13) (IC (95)=[63.97-99.81]). The specificity of the method was 100%, as was the positive predictive value, because no sentinel node was diagnosed positive wrongly on frozen sections among patients without true histological node metastasis. DISCUSSION: For routine care of patients with squamous-cell carcinoma of the oral cavity and the oropharynx detection of the sentinel lymph node is proposed primarily for patients with T1T2N0 staging. Larger tumors can modify the architecture and flow within the lymphatic ducts, and consequently even the concept of a sentinel lymph node. Systematic neck dissection is required or T3T4, even when N0. Our series of T1T2N0 tumors is too small to enable statistically significant conclusions. A low level of false-negative in a larger series would be necessary to propose this technique instead of convention neck dissection for T1T2 tumors of the oral cavity and oropharynx.

Carcinoma, Squamous Cell↗
PubMed2005

[Anhidrotic ectomermal dysplasia (AED): four cases].

INTRODUCTION: Anhidrotic ectodermal dysplasia (AED) or Christ-Siemens-Touraine syndrome is a rare, hereditary genodermatosis, classically X-linked recessive disorder. MATERIAL AND METHODS: [corrected] We report the cases of 3 children and a male adult. RESULTS: The mode of diagnosis, the clinical signs and the therapeutic option are detailed. DISCUSSION: AED is characterized by a malformative state derived from the ectodermal layer of the embryo which results in the triad: anhidrosis (or hypohidrosis), hypotrichosis, anodontia (or hypodontia). Hypohidrosis causes thermoregulation disorders, which in the infant, can be life threatening. It is important to recognize the affection early to avoid accidents of hyperthermia. Once the diagnosis is established, family investigations are necessary to determine whether it is a family form or a new sporadic case. Carrier mothers must be informed of the high risk recurrence for future male infants. Symptomatic maxillo-facial treatment strives to improve masticatory function and facial growth and thus limit the psychological impact and improve patient comfort.

Adult↗
PubMed2005

Gunshot wounds: reconstruction of the lower face by osteogenic distraction.

BACKGROUND: Although osteogenic distraction is a well-established technique, the distraction device still needs to be improved, miniaturized, and made lighter, more flexible, and more adaptable for mandibular reconstruction in adults with gunshot wounds. The authors successively used unidirectional and bidirectional devices, followed by a bone transporter with a horseshoe-shaped trammel. The trammel system was then replaced by an endless screw, and finally by a customized endless screw. METHODS: Eleven adult patients with gunshot injuries underwent mandibular reconstruction using osteogenic distraction with an external device. RESULTS: An average bone gain of 79 mm was achieved. No infectious complications were observed. The authors encountered equipment problems during the study, requiring a change of material. The mean duration of mandibular distraction was 3.5 months. CONCLUSIONS: Distraction of bone fragments facilitates the simultaneous expansion of soft tissues, avoiding free or pedicled myocutaneous flaps, for soft-tissue reconstruction. The alveolar ridge with the attached gum is also recreated by distraction, allowing dental reconstruction by osseointegrated implants.

Adult↗
PubMed2005

Maillard reaction products derived from thiol compounds as inhibitors of enzymatic browning of fruits and vegetables: the structure-activity relationship.

Some thiol-derived Maillard reaction products (MRPs) may exert antioxidant activity, depending on the reaction conditions as well as on the sugar and the sulphydryl compound. Recently, we reported that MRPs derived from glucose or fructose with cysteine (CSH) or glutathione (GSH) mixtures greatly inhibited polyphenoloxidases (PPOs), oxidoreductases responsible for discoloration of fresh or minimally processed fruits and vegetables. Glucose and GSH were shown to be the most active in producing inhibitory MRPs. Therefore, we examined the way in which the nature of the reactants affected their synthesis, in order to establish a structure-activity relationship for the inhibitory products. Various aqueous (0.083 M, 0.125 M, or 0.25 M) mixtures of a sugar (hexose, pentose, or diholoside) with either a CSH-related compound (CSH, GSH, N-acetyl-cysteine, cysteamine, cysteic acid, methyl-cysteine, cysteine methyl ester), an amino acid (gamma-glutamic acid, glycine, methionine), or other sulfur compound (thiourea, 1,4-dithiothreitol, 2-mercaptoethanol) were heated at 103 degrees C for 14 h. Soluble MRPs were compared for their ability to inhibit apple PPO activity. In the presence of CSH, the rated sugars (same molar concentration) ranked as to inhibitory effect were pentoses > sucrose > hexoses > or = maltose. In the presence of glucose, the simultaneous presence of an amino group, a carboxyl group, and a free thiol group on the same molecule seemed essential for the production of highly inhibitory compounds.

Cysteine↗
PubMed2004

Threshold extraction in metabolite concentration data.

MOTIVATION: Continued development of analytical techniques based on gas chromatography and mass spectrometry now facilitates the generation of larger sets of metabolite concentration data. An important step towards the understanding of metabolite dynamics is the recognition of stable states where metabolite concentrations exhibit a simple behaviour. Such states can be characterized through the identification of significant thresholds in the concentrations. But general techniques for finding discretization thresholds in continuous data prove to be practically insufficient for detecting states due to the weak conditional dependences in concentration data. RESULTS: We introduce a method of recognizing states in the framework of decision tree induction. It is based upon a global analysis of decision forests where stability and quality are evaluated. It leads to the detection of thresholds that are both comprehensible and robust. Applied to metabolite concentration data, this method has led to the discovery of hidden states in the corresponding variables. Some of these reflect known properties of the biological experiments, and others point to putative new states. AVAILABILITY: An implementation of this approach can be obtained from the authors upon request.

Algorithms↗
PubMed2004

[Rhytidectomy and Raynaud's phenomenon: about two cases].

Raynaud's phenomenon is a currently vascular syndrome (8 to 10% of women and 3 to 5% of men). It was defined as episodic ischaemia of the fingers, toes, nose, ears and nipples, which presents clinically as pallor, cyanosis, and often rubor of the skins, in response to cold, emotional stimuli and vasoconstriction agents. The phenomenon is caused by a vasoconstriction of arterials skin. In severe forms of the phenomenon, we can see ulcerations and necrosis. We report here two cases of rhytidectomy flap necrosis in Raynaud's Phenomenon. After review of literature, we explain the elements of physiopathology whose can explain these complications and we try to establish recommendations to these complications.

Female↗
PubMed2003

[HIV-1 infection in children in African countries].

The prognosis of HIV infection is dramatic for children living in poor countries. Over 50% die within two years. The World Health Organization has estimated that 1500 children will be infected daily until large-scale national programs for prevention of mother-to-child transmission are implemented. A better understanding of the causes underlying early morbidity could lead to a substantial reduction in mortality pending use of antiretroviral drugs which have demonstrated promising results in preliminary tests on children in poor countries.

Adult↗
PubMed2002

Genome-wide distribution and potential regulatory functions of AtATE, a novel family of miniature inverted-repeat transposable elements in Arabidopsis thaliana.

A study of transgenic promoter::beta-glucuronidase lines showed that the promoters of the two Arabidopsis ARGININE DECARBOXYLASE paralogues, ADC1 and ADC2, exhibited extremely different patterns of activity. One major feature of the promoter of ADC1 was the presence of a novel transposable element, which was shown to possess all of the characteristics of Miniature Inverted-repeat Transposable Elements (MITEs), and to be present in 26 full-length copies and 1617 partial copies and fragments distributed throughout the Arabidopsis genome. TRANSFAC analysis showed that this transposable element possesses a significant number of transcription-factor binding motifs. A bioinformatics approach based on a suffix-tree compilation was used to obtain an exhaustive description of exact copy numbers and positions of the element in the Arabidopsis genome. The distribution among the chromosomes was non-random, and a significant number of copies were found in regions flanking genes. Full-length copies of the transposable element were detected in the immediate vicinity of 22 genes, either upstream or downstream.

Arabidopsis↗
PubMed2001

Environmental xenoestrogens, antiandrogens and disorders of male sexual differentiation.

Over the past 20 years, the documented increase in the disorders of male sexual differentiation, such as hypospadias, cryptorchidism, and micropenis, has led to the suspicion that environmental chemicals are detrimental to normal male genital development in utero. Male sexual differentiation is critically dependent on the normal action of androgens, and unbalanced androgen/estrogen ratios can disturb it. Environmental xenoestrogens (such as herbicides, pesticides, PCBs, plasticizers, and polystyrenes) that mimic estrogens or environmental antiandrogens (such as polyaromatic hydrocarbons, linuron, vinclozolin, and pp'DDE) that disturb endocrine balance, cause demasculinizing effects in the male foetus. These environmental chemicals are often referred to as endocrine disruptors: they are thought to mimic endogenous estrogens by entering the cell, binding to the receptor and activating transcription, they may also antagonize normal androgen action. We have established numerous cell lines to assess the estrogenicity and antiandrogenicity of compounds found in the environment and to identify new products present in wastewater effluents that are able to disrupt endocrine functions. Several cell lines responding to estrogens have been obtained in our group, including cells with different enzymatic equipment and cells expressing chimeric receptor or natural estrogen receptors alpha and beta. These cell lines have proved to be useful for assessing the biological activity of pesticides, fungicides, and chemicals found in plastic or discarded in the environment. In order to generate a powerful tool for the investigation of androgen action and the rapid screening of potential antagonists, we developed a new stable prostatic cell line. The PALM cell line is an original cellular model to characterize the response of hAR, and it provides an easy and rapid bioluminescent test to identify new antagonists. We also developed a model based on a fusion protein between the androgen receptor (AR) and the green fluorescent protein (GFP) to study the intracellular dynamics of AR. The GFP-AR model was applied to define the ability of several xenoestrogens and antiandrogens to inhibit the nuclear transfer of AR. The ubiquitous presence of endocrine disruptors in the environment and the increased incidence of neonatal genital malformation support the hypothesis that disturbed male sexual differentiation may in some cases be caused by increased exposure to environmental xenoestrogens and/or antiandrogens.

Androgen Antagonists↗
PubMed2001

[Family socioeconomic deprivation and vulnerability in the pediatric emergency room: evaluation and management].

OBJECTIVE: The aim of this study was to evaluate the importance of socioeconomic deprivation and other forms of vulnerability in families attending the pediatric emergency unit (PEU). It was based on a five-level classification of family types and an analysis of responses provided by the French healthcare system. METHOD: The prospective study involved 150 families admitted to the PEU on the basis of open-response interviews that analyzed demographic and socio-economic characteristics, motivations for consultation, the child's quality of life, family problems experienced by the parents, and their support network. RESULTS: Five categories of families were defined as follows: complete destitution necessitating immediate social measures (0.7%); acknowledged and well-managed economic deprivation (13.3%), unacknowledged and/or complex economic deprivation with a significant deterioration in the quality of life (22.2%), familial psychological vulnerability without economic deprivation (30.4%), and families without any apparent problems (33.7%). Consultation at the PEU appears to be a multifactorial phenomenon motivated by socioeconomic, psychological and cultural factors. This phenomenon is connected with the present-day imbalance in the healthcare system, which does not adequately respond to the needs of vulnerable families. CONCLUSION: This survey contributes to the current reflection on the integration of psychosocial factors in child healthcare at both the hospital and local community level. The method described herein has determined the factors of vulnerability and the risks of economic deprivation. It can contribute to the development of improved communication and cooperation between practitioners, the hospital and local social workers.

Adult↗
PubMed2001

Lingual ultrastructure of the long-finned pilot whale (Globicephala melas).

Microscopic studies on the cetacean tongue are limited and, to date, only a few ultrastructural reports on dolphins have been published. This report presents the initial description of the lingual ultrastructure of the long-finned pilot whale. The lingual integumental surface was smooth, lacking papillae, although flaking of outer stratum corneum cells could be observed at high resolution. The keratinocytes of the stratum spinosum of the epidermis resembled those of cetacean skin on other regions of the body. The similarities included the presence of cytoplasmic lipid droplets around the nuclei of stratutm spinosum cells, a lingual feature not seen in terrestrial mammals. Keratin intermediate filaments were numerous and occasionally formed aggregates of circular whorls. At cell surfaces, bundles of keratin intermediate filaments were frequently observed inserting into desmosomal plaques. Pigment granules were not evident and organelles were sparse. Stratum corneal cells contained nuclear remnants (parakeratosis) and small multivesicular bodies, and the corneal layer was approximately 18 cells thick. The nuclei of the stratum basale keratinocytes possessed exceptionally numerous and deep clefts. The dermis was nondistinctive. The skeletal muscle of the tongue was arranged in widely separated fasiculi containing small numbers of muscle fibres. Typical fine structure of skeletal muscle bands and tubular elements was observed by transmission electron microscopy.

Animals↗
PubMed2001

Sensor arrays: an inspired idea or an objective measurement of environmental odours?

The measure of annoyance odours from sewage tratment, landfill and agricultural practise has become highly significant in the control and prevention of dorous emissions from existing facilities and its crucial for new planning applications. Current methods (such as GC-MS analysis, H2S and NH3 measurements) provide an accurate description of chemical compositions or act as surrogates for odour strength, but tell us very little about the perceived effect, whereas olfactometry gives the right human response but is very subjective and expensive. The use of non-specific sensor arrays may offer an objective and on-line instrument for assessing olfactive annoyance. Results have shown that sensor array systems can discriminate between different odour sources (wastewater, livestock and landfill). The response patterns from these sources can be significantly different and that the intensity of sensor responses is proportional to the concentration of the volatiles. The correlation of the sensors responses against odour strengths have also shown that reasonable fits can be obtained for a range of odour concentrations (100-800,000 ou/m3). However, the influence of environmental fluctuations (humidity and temperature) on sensor baselines still remains an obstacle, as well as the need for periodic calibration of the sensory system and the choice of a suitable gas for different environmental odours.

Agriculture↗