Biomedical subjects

M Mesbah

Publications and source records attributed to M Mesbah.

At least 19 recordsLinked to original sources

PubMed2007

A matching pursuit-based signal complexity measure for the analysis of newborn EEG.

This paper presents a new relative measure of signal complexity, referred to here as relative structural complexity (RSC), which is based on the matching pursuit (MP) decomposition. By relative, we refer to the fact that this new measure is highly dependent on the decomposition dictionary used by MP. The structural part of the definition points to the fact that this new measure is related to the structure, or composition, of the signal under analysis. After a formal definition, the proposed RSC measure is used in the analysis of newborn electroencephalogram (EEG). To do this, firstly, a time-frequency decomposition dictionary is specifically designed to compactly represent the newborn EEG seizure state using MP. We then show, through the analysis of synthetic and real newborn EEG data, that the relative structural complexity measure can indicate changes in EEG structure as it transitions between the two EEG states; namely seizure and background (non-seizure).

Algorithms↗

PubMed2004

Blindness, low vision, and other handicaps as risk factors attached to institutional residence.

AIMS: To estimate the risk of living in an institution and being visually impaired. METHODS: Two national surveys were pooled: (1) 2075 institutions (for children or adults with handicaps, old people, and psychiatric centres) were selected randomly, in 18 predefined strata, from the French health ministry files. From these institutions, 15 403 subjects were selected randomly and handicap was documented by interview in 14 603 (94.9%) of them; (2) level of handicap was documented in a randomised, stratified sample of 356 208 citizens living in the community; from this sample, 21 760 subjects were further selected at random and 16 945 people were interviewed. Data on handicaps (visual, auditory, speech, brain, visceral, motor, and other) and activities of daily living (ADL) were extracted. The odds ratio (OR) of living in an institution was estimated, using stepwise logistic regressions with age, geographical area, handicaps, and ADL as co-variables. RESULTS: Subjects in institutions, compared to those living at home, were, respectively, more often female (64.3% v 52.4%) and older (68.7 v 38.0 years); they more often had handicaps (ORs: speech, 6.59; brain, 10.17; motor, 8.86; visceral, 3.49; auditory, 2.66; other, 1.53); and were less often able to perform their ADL (46.2% v 97.1%) without assistance. Below 80 years, blind people were more often in institutions (ORs 0.239 to 0.306); whereas in older people the association was reversed (OR: 3.277). Low vision was always significantly associated with institutional residence (ORs from 0.262 to 0.752). CONCLUSION: Visual handicap was associated with institutional residence. The link persisted after adjustment for known confounding factors.

Activities of Daily Living↗

PubMed2003

Putative membrane receptor for 1,25(OH)2 vitamin D3 in human mineralized tissues during prenatal development.

The calciotropic hormone, 1,25(OH)2vitamin D3[1,25(OH)2D3], controls the formation of dental and bone mineralized tissues. The role of nuclear 1,25(OH)2D3 receptor has been extensively studied in the diverse secretory cells, i.e., osteoblasts, chondrocytes, ameloblasts, and odontoblasts. A nongenomic pathway also has been characterized and related to the interactions of 1,25(OH)2D3 ligand with a putative cell membrane receptor. This recognition moiety called 1,25(OH)2vitamin D3 membrane-associated, rapid-response steroid-binding [1,25D3-MARRS] protein is investigated here in the craniofacial skeleton of human embryos and fetuses. Immunolocalization using a specific Ab099 against chick intestinal basolateral 1,25D3-MARRS protein was performed. The data show a complementary expression pattern of the membrane receptor when compared with published data on the nuclear receptor, notably during amelogenesis. In mandible, membrane receptors for 1,25(OH)2D3 were identified in the heterogenous bone cell population, including osteoblasts and osteoclasts. Differential 1,25D3-MARRS protein levels were observed in distinct developmental stages and anatomical sites of tooth and bone, suggesting the existence of cross-talk between local factors and 1,25D3-MARRS protein expression.

Gestational Age↗

PubMed2002

Investigation of osteocalcin, osteonectin, and dentin sialophosphoprotein in developing human teeth.

Biochemical investigations in rodents have shown that numerous mineralized matrix proteins share expression in bone, dentin, and cementum. Little information is available regarding the expression pattern of these proteins in human tissues, particularly during tooth formation. The aim of this study was to identify the expression pattern of the two major noncollagenous proteins of bone and dentin, osteocalcin (OC) and osteonectin (ON), in comparison to the dentin-specific protein, dentin sialophosphoprotein (DSPP). Mandibles from fetuses (5-26 weeks), neonate autopsies, forming teeth from 10-12-year-old patients, third molars extracted for orthodontic reasons, and bone tumors were collected with approval from the National Ethics Committee. Human OC, ON, and DSPP mRNAs were detected by reverse transcription-polymerase chain reaction (RT-PCR) in fetal mandibles (5-11 weeks) and in primary cell cultures of dental pulp. In addition, OC, ON, and DSPP proteins were localized in forming human mineralized tissues using immunohistochemistry. In vivo, DSPP expression was associated with tooth terminal epithelial-mesenchymal interaction events, amelogenesis and dentinogenesis. Transient DSPP expression was seen in the presecretory ameloblasts with continuous expression in the odontoblasts. In contrast, both osteoblasts and odontoblasts showed a temporal gap between OC and ON expression in early development. ON was expressed in the initial stages of cytodifferentiation, whereas OC was expressed only during the later stages, especially in the teeth. At the maturation stage of enamel formation, both proteins were detected in odontoblasts and their processes within the extracellular matrix. In contrast to bone, OC was not localized extracellularly within the collagen-rich dentin matrix (predentin or intertubular dentin), but was found in the mature enamel. ON was present mostly in the nonmineralized predentin. These results demonstrate for the first time that both OC and ON are produced by human odontoblasts and determine the expression pattern of DSPP in human teeth, and suggest that OC and ON move inside the canalicule via odontoblast cell processes becoming localized to specific extracellular compartments during dentin and enamel formation. These distinct extracellular patterns may be related to the nature of DSPP, OC, and ON interactions with other matrix-specific macromolecules (i.e., amelogenin, dentin matrix protein-1) and/or to the polarized organization of odontoblast secretion as compared with osteoblasts.

Adult↗

PubMed2002

Msx1 is a regulator of bone formation during development and postnatal growth: in vivo investigations in a transgenic mouse model.

The present study is devoted to Msx1 distribution and function from birth to 15 months, events and periods still unexplored in vivo using Msx1 knock in transgenic mice. The study is focused on the mandible, as an exemplary model system for Msx1-dependent neural crest-derived skeletal unit. The transgenic line enabled study of morphological abnormalities in Msx1 null mutation mice and Msx1 protein expression in Msx1+/- heterozygous mice. In Msx1 null mutation, the most striking feature was an inhibition of the mandibular basal convexity, the absence of teeth and alveolar bone processes, and absence of endochondral ossification in the mandibular condyle. At birth, in Msx1+/- heterozygous animals, we identified for the first time a double Msx1 aboral-oral and disto-proximal gradient field developmental pattern located in the low border of the mandibular bone in relation with this bone segment modeling. Msx1 expression involved both osteoblast and osteoclast cells. A distinct pattern characterized bone surfaces: Periosteum osteoblast differentiation was related to Msx1 down-regulation, while in the endosteum both differentiated osteoblasts and osteoclasts expressed the homeoprotein. In postnatal stages, Msx1 expression was maintained in the alveolar bone processes and dento-alveolar cells in relation with tooth function. Our data suggest that Msx1 play a role in a site-specific manner not only in early patterning but also in skeletal growth and modeling by acting on heterogenous bone cell populations.

Animals↗

PubMed2002

Cross-talk between Msx/Dlx homeobox genes and vitamin D during tooth mineralization.

Rickets is associated with site-specific disorders of enamel and dentin formation, which may reflect the impact of vitamin D on a morphogenetic pathway. This study is devoted to potential cross-talk between vitamin D and Msx/Dlx transcription factors. We raised the question of a potential link between tooth defects seen in mice with rickets and Msx2 gene misexpression, using mutant mice lacking the nuclear vitamin D receptor as an animal model. Our data showed a modulation of Msx2 expression. In order to search for a functional impact of this Msx2 misexpression secondary to rickets, we focused our attention on osteocalcin as a target gene for both vitamin D and Msx2. Combining Msx2 overexpression and vitamin D addition in vitro, we showed an inhibitory effect on osteocalcin expression in immortalized MO6-G3 odontoblasts. Finally, in the same cells, such combinations appeared to modulate VDR expression outlining the existence of complex cross-regulations between vitamin D and Msx/Dix pathways.

Animals↗

PubMed2001

Postnatal Msx1 expression pattern in craniofacial, axial, and appendicular skeleton of transgenic mice from the first week until the second year.

Phenotypes associated with Msx1 mutations have established the prominent role of this divergent homeogene in skeletal patterning. Previous studies have been achieved during antenatal development in relation with the early death of null mutant mice. Therefore, the present study is devoted to Msx1 homeogene in the postnatal craniofacial, axial, and appendicular skeleton. A knock-in transgenic mouse line was studied from the first postnatal week until 15 months. Whole-mount beta-galactosidase enzymology identified Msx1 protein expression pattern. Maintained expression of Msx1 was observed in growing and adult mice, specifically in the sites where Msx1 plays an early morphogenetic role during initial skeletal patterning. These included the craniofacial sutures, autopodium, mandible, and alveolar bone. Furthermore, active membranous and endochondral bone formation involved Msx1 in the entire skeleton. Histologic sections showed that progenitor as well as differentiating and differentiated cells of all the bone cell lineages could express the Msx1 protein (chondrocytes, osteoblasts, tartrate-resistant acid phosphatase positive osteoclasts and chondroclasts). Recent developments in the genetic and developmental biology of skeletal morphogenesis demonstrate that genes critical for development are jointly expressed in discrete embryonic signalling and growth centers, the enamel knot in teeth, the cranial suture in skull morphogenesis, and the progress zone in the limb buds. The present study suggests that these signalling pathways are jointly important throughout the entire lifetime with an exquisite site-specificity spatially related to early patterning.

Animals↗

PubMed2000

Prevention of recurrent depressive episodes with milnacipran: consequences on quality of life.

BACKGROUND: Depression is now seen as a chronic disabling condition that spans the patient's lifetime and creates significant medical, economic and quality of life consequences. METHODS: 500 depressed patients were treated with milnacipran for 6 months. A total of 214 recovered patients were randomised to receive either milnacipran (50 mg bid) or a matching placebo for a 1-year recurrence prevention phase. Recurrence rate was the primary criteria; quality of life (QoL) consequences were evaluated through a shortened version of the French Sickness Impact Profile (SIP), the Depression Impact Profile (DIP). RESULTS: Milnacipran demonstrated its ability to reduce recurrences (Odds-Ratio=1.5; P<0.05), with a more marked effect in recovered patients with few residual symptoms (Odds-Ratio=3.0). Responders who continued treatment with milnacipran had a dramatic improvement in their quality of life, although patients with residual symptoms still experienced some deterioration in their QoL (recreation, emotional, social, alertness and home assistance scores). Even recovered patients having zero scores on the Hamilton Depression Rating Scale-21 items (HDRS) had some QoL deterioration. The DIP emotional score was found to be more predictive of recurrence than the HDRS. Overall, the QoL was improved for those in the milnacipran group in comparison to placebo on the mobility, communication, psycho-social and total scores. LIMITATIONS: The QoL evaluation was a secondary criteria; no a priori sample size estimate was performed. The choice of a generic QoL instrument might have reduced the sensitivity to clinical changes in depression. CONCLUSIONS: Prevention of recurrence in MDD with milnacipran contributes to an improvement in the QoL.

Adolescent↗

PubMed2000

FISH to mitotic chromosomes and extended DNA fibres of Beta procumbens in a series of monosomic additions to beet (B. vulgaris).

The physical localization and organization of a Procumbentes-specific repetitive DNA sequence, PB6-4, on the chromosomes of Beta procumbens (2n = 18) were studied, using FISH (fluorescence in situ hybridization) to mitotic chromosomes and extended DNA fibres. The chromosomes of B. procumbens were studied in metaphase complements of the species itself, as well as in preparations of a series of eight different B. procumbens-derived monosomic additions to B. vulgaris (2n = 18). FISH to chromosome spreads of B. procumbens revealed that PB6-4 hybridizes to all chromosomes, predominantly in the pericentromeric regions, but with differences in size and brightness of the signals. Hybridization of PB6-4 to metaphase complements of B. vulgaris revealed no signals, indicating that cross-hybridization with the genome of this species was negligible. Consequently, hybridization of PB6-4 to metaphase complements of the monosomic additions yielded fluorescent signals on the alien chromosomes only. The previously observed differences in size and brightness of the fluorescent spots were confirmed using the single alien chromosomes. FISH of PB6-4 to extended DNA fibres of the monosomic additions indicated differences in the fluorescent track lengths between the alien chromosomes. Measurements of the fluorescent tracts allowed classification into discrete groups, varying from one to three groups per B. procumbens chromosome. The data revealed that the brightness or size of the signal at mitotic metaphase and the length of the fluorescent tracks on the DNA fibres were correlated.

Chenopodiaceae↗

PubMed2000

Cloning, characterization and immunolocalization of human ameloblastin.

Amelogenesis imperfecta is a broad classification of hereditary enamel defects, exhibiting both genetic and clinical diversity. Most amelogenesis imperfecta cases are autosomal dominant disorders, yet only the local hypoplastic form has been mapped to human chromosome 4q between D4S242 1 and the albumin gene. An enamel protein cDNA, termed ameloblastin (also known as amelin and sheathlin), has been isolated from rat, mouse and pig. Its human homolog has been mapped to chromosome 4q21 between markers D4S409 and D4S400, flanking the local hypoplastic amelogenesis imperfecta critical region. Therefore, ameloblastin is a strong candidate gene for this form of amelogenesis imperfecta. To facilitate genetic studies related to this dental disease, we isolated and characterized a human ameloblastin cDNA. A human third molar cDNA library was screened and two ameloblastin clones identified. Nucleotide sequencing of these cDNAs indicated alternative splicing of the putative open reading frame, use of different polyadenylation signals, and a high degree of similarity to reported rat, mouse and porcine cDNAs. Immunohistochemistry studies on embryonic human teeth using an antibody to recombinant ameloblastin indicated ameloblastin expression by ameloblasts with localization in the enamel matrix associated with the sheath structures.

Alternative Splicing↗

PubMed1999

Construction of a scale measuring inpatients' opinion on quality of care.

OBJECTIVE: To develop a reliable and valid measure of patient opinions on quality of hospital care. DESIGN: Issues of importance to patients and possible scale items were generated by literature review and non-structured interviews of patients, former patients, health care providers and researchers. Semi-structured interviews with inpatients and pilot studies were conducted to modify or remove ambiguous questions and reduce skewed responses. A study was then made to select from these questions relevant items and variables correlated to patient evaluation of quality of care. A principal-components analysis was performed to select items and assess construct validity. Cronbach's alpha coefficients were calculated to estimate the reliability of the scale. Time reliability and concurrent validity were also considered. SETTING: An 800-bed French short-stay teaching hospital in Paris. STUDY PARTICIPANTS: Five-hundred and thirty-four consecutive patients hospitalized in eight medical and surgical wards. RESULTS: A 26-item scale was developed. Component analysis indicated two subscales: 'medical information' and 'relationship with staff and daily routine'. Levels of reliability were satisfactory: Cronbach's alpha coefficient exceeded 0.87 for overall scale and subscales. Concurrent validity and time reliability were also satisfactory. Multivariate analysis showed that, taking into account patients and hospitalization characteristics linked to scores (age, health status, number of hospitalizations, comorbidity, time since diagnosis, admission pattern, private patient and difficulties reported by staff), these scores differed among departments. CONCLUSION: A reliable, valid measure of inpatients' opinions on quality of care has been developed in a French hospital and variables that have to be taken into account to compare hospital departments have been selected. Items selected in the scale emphasized the importance that patients give to receiving medical information.

Aged↗

PubMed1999

[Internal statistical validation of a quality of life questionnaire].

In this paper we present two different statistical approaches to evaluate the psychometric properties of a quality of life questionnaire. First the study of the factorial structure is briefly exposed. Then we present the unidimensional classical models. They are based on the linear relationship between the observed score and the true score. The definition of the reliability was first addressed in this classical framework. Its estimation with the Cronbach alpha coefficient is one important feature of the evaluation of an instrument. More recently, modern response theory gives a better statistical framework to deal with unidimensional latent traits. These models describe the probability of positive answer to an item as a function of the actual value of the latent trait and an item parameter. We expose the principles of the Rasch model: hypothesis, estimations methods and fit tests. Finally practical applications to the validation process of a questionnaire are explored with data from a study of a short French version of the SIP questionnaire.

Evaluation Studies as Topic↗

PubMed1998

French cross-cultural adaptation of the Health Utilities Indexes Mark 2 (HUI2) and 3 (HUI3) classification systems. Clinical and Economic Working Groups.

The McMaster Health Utilities Indexes Mark 2 (HUI2) and 3 (HUI3) are multiattribute health classification systems, for which multiattribute preference functions have been developed in Canada. They provide a comprehensive instrument for use in economic evaluations and population health survey studies. This paper reports on the first results on the adaptation of the HUI2 and HUI3 systems cross-culturally and the assessment of the validity and reliability of the French self-report questionnaire in different patient populations. The cross-cultural adaptation included translation, backtranslations, an expert consensus meeting and pre-test with a few patients and healthy subjects in order to produce a conceptually equivalent French version of the 15 question self-report questionnaire and the HUI2 and HUI3 classification systems. Different groups of patients attending specialized clinics (n = 709) completed the questionnaire and another generic questionnaire (the Sickness Impact Profile (SIP)) for validity assessment. Physicians and patients were also asked for a global subjective assessment of the patient's health status. The French questionnaire was well received by the patients. The criterion and convergent validities of both classification systems (correlations with the patients' and physicians' assessments and with the responses to the SIP questionnaire) were satisfactory. The internal consistency was acceptable too (Cronbach's alpha = 0.81), as was the 3 day test-retest reproducibility. These first results authorize careful use of the 15 question self-report questionnaire in French. An assessment of the multiattribute preference function for the HUI3 system in France will be the study's next objective.

Adolescent↗

PubMed1998

Heterotopic triplet pregnancy. Report of a case with successful twin intrauterine gestation.

BACKGROUND: Reports of coexisting multiple intrauterine pregnancies and ectopic pregnancy are extremely rare. We present one case with early sonographic diagnosis of heterotopic pregnancy, successful laparoscopic treatment and a subsequent normal pregnancy course and outcome of the intrauterine twin gestation. CASE: A 29-year-old woman, gravida 1, para 0, presented for her first prenatal visit at 5 weeks of gestation with pelvic pain. She had conceived with 75 IU leutinizing hormone and follicle-stimulating hormone and homologous intrauterine insemination. The sonogram confirmed a dichorionic twin intrauterine pregnancy and left tubal pregnancy at 7 weeks of gestation. The patient underwent a laparoscopic left salpingostomy and removal of the ectopic pregnancy. Level II sonogram showed a grossly unremarkable twin gestation at 20 weeks. Labor was induced at 37 weeks of gestation due to mild preeclampsia and underwent vaginal delivery without difficulties. The first twin was a girl, weighing 2,722 g, with Apgar scores of 9/9. The second twin, a boy, was delivered 10 minutes later, weighing 2,863 g, with Apgar scores of 9/9. CONCLUSION: Early sonography is essential for the diagnosis of heterotopic pregnancy, and timely surgical intervention can save the intrauterine twin gestation, with a subsequent normal pregnancy course and outcome.

Adult↗

PubMed1997

Handedness scale: how many and which items?

A stepwise analysis of the Cronbach Alpha Coefficient (CAC) was performed on five large samples of adults and young children, in order to choose the ''minimum'' set of items of a handedness scale which gives the maximum reliability. In adults, a handedness scale with 12 items has nearly the same or even a better CAC than other scales with more items; so, a choice of 10 to 12 items seems to be adequate. For children, a scale with eight items seems to be quite reliable but it is not impossible that a scale including more items would lead to a slight increase of CAC. The controversial usefulness of a precise assessment of the ''general handedness factor'' (the first principal component) generated by handedness questionnaires and its J-shaped distribution in the general population are discussed.

Journal Article↗

PubMed1996

The Asthma Impact Record (AIR) index: a rating scale to evaluate the quality of life of asthmatic patients in France.

Asthma is a chronic disease, which affects patients' daily lives. The goal of this study was the development of a disease-specific scale to evaluate quality of life in asthmatic patients in France: The Asthma Impact Record Index (AIR Index). The study was conducted with the participation of 486 asthmatic patients using the following steps: 1) selection of dichotomous items; 2) reduction of the number of items; 3) study of reproducibility of the questionnaire; 4) weighting of items; 5) study of the reliability and validity of the final version of the AIR Index. The final version of the AIR Index contains 63 unweighted items. The items were classified into subscales representing the main dimensions of quality of life: 1) physical, which was itself split into two subscales: a) physical activities; and b) symptoms; 2) psychological; and 3) social or relational. The internal consistency, measured by Cronbach's alpha coefficients, was found to be high, for the global scale and all subscales (range 0.79-0.94). The concurrent validity, evaluated by studying the relationship between the score values on the global scale and the subscales, and the parameters reflecting disease severity, was also high. We conclude that the AIR Index might represent a useful evaluative and discriminant instrument in studying quality of life in asthma in French populations.

Adult↗

PubMed1995

[Preliminary analysis of the psychometric properties of the French version of an international questionnaire measuring the quality of life: the MOS SF-36 (version 1.1)].

The International Quality of Life Assessment (IQOLA) Project is a 4 year project initiated in 1991 to translate and adapt the Medical Outcome Study Short Form 36 item Health Survey (SF-36) in at least 15 countries. This paper reports on the preliminary psychometric assessment of the SF-36 in French (version 1.1). The validation data come from two studies: a phase IV study of 121 patients with arthritis and a phase IV study of 159 patients with angina. In both cases, the patients were surveyed using the SF-36 and a disease specific module. The main objective of this analysis was to determine how well the scaling assumptions (summated rating or Likert type scaling construction) of the SF-36 were satisfied. Item convergent validity was supported as items-scale correlation range from 0.47-0.87. Item discriminant validity was supported as all items were more correlated with their hypothesised scales than with scales measuring other concepts. Our data support the assumption that the items measuring the same concept had approximately equal variance. Items in a given scale contained about the same proportion of information about the concept being measured, as most items of any given dimension had approximately the same correlation with that dimension. The Cronbach alpha coefficient ranged between 0.79 and 0.95. The correlation between two scales was less than the reliability coefficient for those scales, and these correlations adjusted for attenuation were less than 1. These preliminary results are encouraging. They indicate that the items are linearly related to the underlying concept being measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Prevalence of non-insulin dependent diabetes as perceived by general practitioners in France.

A representative, random sample of French general practitioners, reported the number of diabetic patients they treated in their practices. The resulting NIDDM prevalence rate for France was 1.71% (SE +/- 0.03), compatible with the rates found in other studies. Prevalence rates for NIDDM were also calculated by region and a multivariate covariance model was used to correlate the prevalence with known risk factors. The three significant factors were: the quantity of wine consumed, the female/male sex ratio of people over 45 years of age, both positively correlated, and the consumption of animal fats, which was negatively correlated with NIDDM prevalence.

Aged↗