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Biomedical subjects

P Gillet

Publications and source records attributed to P Gillet.

At least 19 recordsLinked to original sources
PubMed2002

MRI morphometric study and correlation with cognitive functions in young adults shunted for congenital hydrocephalus related to spina bifida.

We studied the morphometric MRI findings and their correlation with cognitive functions in a population of 10 young adults shunted for congenital hydrocephalus related to spina bifida. Morphometric MRI analysis included measurement of the ventricular dilatation index, frontal and occipital parenchymal thickness and the size of the corpus callosum. The neuropsychological status was evaluated, notably to look for a discrepancy between verbal and performance skills, a finding which has previously been described in hydrocephalic children. We also investigated whether there was a correlation between cognitive function and cerebral morphometric indexes. In each case, MRI demonstrated the structural changes associated with the Chiari II malformation. The size of the lateral ventricles varied, ranging from important dilatation to small ventricles. Six patients had only partial development of the corpus callosum. All patients had a normal global IQ. In our population of young adults, we did not observe any discrepancy between verbal and visuospatial performances as has been described in children with hydrocephalus. We found no relationship between cognitive function and ventricle dilatation or parenchymal thickness or between the size of the corpus callosum and callosal transfer.

Adolescent↗
PubMed2002

[BREV: a rapid clinical scale for cognitive function evaluation in preschool and school-age children].

BREV, standing for the French "Batterie Rapide d'Evaluation des Fonctions Cognitive", is a rapid test to screen children with disorders of higher functions and to define the patterns of these disorders. We describe here two phases of the validation procedure. The first phase consisted in measuring the internal validity of the scale by testing 500 normal school children free of disability. The validation process provided appropriate values for each of the 18 subtests assessing cognitive functions (oral language, non-verbal abilities, attention and memory, education and memory, educational achievment) in ten age groups from 4 to 8 years. All subtests with the same content for any revealed values which increased significantly with age. Inter-reliability was tested by retesting 70 children. The second phase of validation, comparing BREV results and those from a large classical neuropsychological battery, tested specificity and sensitivity. Each of the BREV subtests were correlated with the similar subtest of the classical battery. Correlations between verbal and non-verbal scores and verbal and performance intellectual quotient (Weschler scale) were very significant. Sensitivity and specificity of BREV were above 75p.100;. This confirms the reliability of this battery for children, with good sensitivity and specificity. BREV is a reliable test, with carefully established norms, appropriate for preschool and school-age children.

Attention↗
PubMed2001

Secular increase in the incidence of hip fractures in Belgium between 1984 and 1996: need for a concerted public health strategy.

OBJECTIVE: To determine the incidence of hip fractures (at the proximal end of the femur) in Belgium from 1984 to 1996. METHODS: Use was made of information from the national database on hospital bills, which fully covers the annual hospital stays in the whole of the country. FINDINGS: The mean annual incidence of hip fractures increased from 107.8 to 140.5 per 100,000 inhabitants between 1984 and 1996. The incidence of fractures of the femoral shaft (diaphysis), taken as a control, remained stable. The female to male ratio of these hip fractures was 2.3:1. Although the incidence by age group was identical for males and females, the fractures occurred approximately seven years earlier in women than in men. The demographic changes observed in Belgium during this period accounted for only 10% of the observed increase in the number of hip fractures. CONCLUSION: If no comprehensive preventive policy is set up promptly, there will be a sevenfold increase in the incidence of hip fractures between now and the year 2050 in Belgium.

Age Factors↗
PubMed2001

An ultradense polymorph of rutile with seven-coordinated titanium from the Ries crater.

We report the discovery of an ultradense post-rutile polymorph of titanium dioxide in shocked gneisses of the Ries crater in Germany. The microscopic diagnostic feature is intense blue internal reflections in crossed polarizers in reflected light. X-ray diffraction studies revealed a monoclinic lattice, isostructural with the baddeleyite ZrO2 polymorph, and the titanium cation is coordinated with seven oxygen anions. The cell parameters are as follows: a = 4.606(2) angstroms, b = 4.986(3) angstroms, c = 4.933(3) angstroms, beta (angle between c and a axes) = 99.17(6) degrees; space group P2(1)/c; density = 4.72 grams per cubic centimeter, where the numbers in parentheses are standard deviations in the last significant digits. This phase is 11% denser than rutile. The mineral is sensitive to x-ray irradiation and tends to invert to rutile. The presence of baddeleyite-type TiO2 in the shocked rocks indicates that the peak shock pressure was between 16 and 20 gigapascals, and the post-shock temperature was much lower than 500 degrees C.

Journal Article↗
PubMed2001

Structural evaluation of articular cartilage: potential contribution of magnetic resonance techniques used in clinical practice.

OBJECTIVE: To determine whether routine magnetic resonance imaging (MRI) techniques can detect age-related structural modifications of bovine articular cartilage. METHODS: The cartilage of 3-month-old, 3-year-old, and 13-year-old animals was studied. T1- and T2-weighted MR sequences were performed using a 1.5T clinical imager and a 3-inch surface coil. Histologic slices (5 microm) of cartilage specimens were stained with picrosirius red (for collagen) and toluidine blue (for glycosaminoglycans [GAGs]). A polarized light study was performed to determine the collagen network organization. Except for the 13-year-old animal cartilage, the biochemical content was studied on slices cut parallel to the surface to determine GAG and hydroxyproline (collagen) content. Cartilage profiles were performed to determine the MR pixel intensity and the histologic color intensity. RESULTS: On T1-weighted images, the cartilage was homogeneous, with pixel intensity profiles presenting low variations. On T2-weighted images, the cartilage was laminar in the 3-month-old animals and became homogeneous thereafter. The pixel intensity varied through the cartilage depth with a profile that depended on the age of the animal. The collagen and GAG staining showed abrupt transitions in the 3-month-old animal, while in older animals the cartilage became more homogeneous with a mild gradient of matrix constituents with depth. These results were confirmed by findings of a biochemical study. In addition to these matrix content variations, the bovine cartilage presented modifications of its collagen network organization with aging. CONCLUSION: The MR T2-weighted sequences depicted signal variations with age in bovine cartilage concomitant with modifications in its structure. If confirmed in clinics, these observations will reinforce the place of MRI in characterizing cartilage with aging and pathologic processes.

Aging↗
PubMed2001

The prevalence of mycotoxins in Kashin-Beck disease.

Mycotoxins are naturally occurring toxic chemical compounds produced by fungi infesting agricultural crops both during their growth and storage. Such secondary metabolites, when ingested, can produce toxic syndromes in humans. As it has been suggested that mycotoxins might be involved in the development of Kashin-Beck disease (KBD), we undertook a survey of barley grains of KBD-affected families and non-affected families in that country. We found, by thin layer chromatography, a hitherto unknown metabolite of Alternaria sp. This was especially common on the barley grains of KBD-affected families.

Alternaria↗
PubMed2001

[BREV: a new clinical scale for the evaluation of cognitive function in school-age and preschool-age children].

BREV (Batterie Rapide d'Evaluation des fonctions cognitives) is a new evaluation test for the screening of cognitive disorders in 4-9-year-old children, based on a neuropsychological process. It is made up of 17 subtests which have been carefully standardized. It is not an intelligence test but a tool for children' health professionals to use as a rapid neuropsychological screening test. It is particularly recommended for any child with a school learning disorder or neurological history with a high risk of cognitive disturbances such as epilepsy. It may also be used as a systematic screening test.

Child↗
PubMed2001

Assessment of rat articular cartilage maturation using 50-MHz quantitative ultrasonography.

OBJECTIVE: The objective was to assess the relationship between maturation-related structural changes of articular cartilage and variations of acoustic parameters estimated using high frequency ultrasonography. DESIGN: Patellae taken from 48 immature Wistar male rats and divided into six age groups (from five to 11 weeks old) were explored in vitro using 50-MHz scanning acoustic microscopy, then assessed by histology for the analysis of the cartilage cell distribution and fibrillar collagen organization. The variation of cartilage proteoglycan and collagen content with age was evaluated. Thickness measurements performed on both B-scan images and histologic sections were compared. Ultrasonic radiofrequency signals reflected by the cartilage surface and backscattered from its internal matrix were processed to estimate the integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB). RESULTS: One-way ANOVA indicated that acoustic parameters and thickness change significantly (P < 0.05) as the animal matures because of age-related changes in cartilage composition and morphology. A moderate correlation was found between IRC and the animal age. The parameter decreased slightly but significantly over time. However, a good correlation was observed between the rat age and the AIB, which decreased significantly over time. The parameter variation was mostly related to the changes in collagen fiber orientation, and/or to a change in cell size, density and organization. CONCLUSIONS: Current results indicate that acoustic properties of cartilage are affected by maturation-related cartilage changes. This suggests that high frequency ultrasonography may serve as a useful means for the investigation of cartilage matrix structural changes occurring under various clinical circumstances, like those observed during osteoarthritis, and for the evaluation of the efficacy of specific therapeutics.

Aging↗
PubMed2001

Neurophysiological basis for neurogenic-mediated articular cartilage anabolism alteration.

This study was designed to investigate the pathways involved in neurogenic-mediated articular cartilage damage triggered by a nonsystemic distant subcutaneous or intra-articular inflammation. The cartilage damage was assessed 24 h after subcutaneous or intra-articular complete Freund's adjuvant (CFA) injection measuring patellar proteoglycan (PG) synthesis (ex vivo [Na(2)(35)SO(4)] incorporation) in 96 Wistar rats. Unilateral subcutaneous or intra-articular injection of CFA induced significant decrease (25-29%) in PG synthesis in both patellae. Chronic administration of capsaicin (50 mg. kg(-1). day(-1) during 4 days), which blunted the normal response of C fiber stimulation, prevented the bilateral significant decrease in cartilage synthesis. Similarly, intrathecal injection of MK-801 (10 nmol/day during 5 days), which blocked the glutamatergic synaptic transmission at the dorsal horn of signal originating in primary afferent C fibers, eliminated the CFA-induced PG synthesis decrease in both patellae. Chemical sympathectomy, induced by guanethidine (12.5 mg. kg(-1). day(-1) during 6 wk), also prevented PG synthesis alteration. Finally, compression of the spinal cord at the T3-T5 level had a similar protective effect on the reduction of [Na(2)(35)SO(4)] incorporation. It is concluded that the signal that triggers articular cartilage synthesis damage induced by a distant local inflammation 1) is transmitted through the afferent C fibers, 2) makes glutamatergic synaptic connections with the preganglionic neurons of the sympathetic system, and 3) involves spinal and supraspinal pathways.

Afferent Pathways↗
PubMed2001

Piroxicam concentrations in plasma and synovial fluid after a single dose of piroxicam-beta-cyclodextrin.

AIMS: The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) in rheumatic diseases depends on their concentrations within the joint. We determined piroxicam concentrations in plasma and synovial fluid (SF) after a single oral dose of 20 mg in the form of one tablet of piroxicam-beta-cyclodextrin. METHODS: 45 patients, aged 21 to 84 years, presenting with an effusion of the knee, related to degenerative or inflammatory joint disease, were included in this study after having given their written consent. One blood and one SF sample were drawn concomitantly in each patient from 0.5 to 48 h after NSAID administration. Piroxicam assays were performed by high performance liquid chromatography. Pharmacokinetic parameters were obtained from the mean plasma and synovial concentrations measured at various sampling times. RESULTS: The peak concentration was higher in plasma (2.51+/-0.25 microg/ml) than in SF (1.31+/-0.76 microg/ml), but the elimination half-life was much longer in SF (90.7 h) than in plasma (32.5 h). The SF/plasma area under the concentration-time curve ratio (evaluating the quantity of NSAID transferred from the blood to the joint) was equal to 0.39. CONCLUSIONS: Piroxicam contained in piroxicam-beta-cyclodextrin diffused well into the SF where its pharmacokinetic profile corresponded to that of a long half-life NSAID.

Administration, Oral↗
PubMed2001

[Familial articular chondrocalcinosis: study of an Alsatian family].

Familial articular chondrocalcinosis is a chronic articular disease characterized by acute intermittent attacks of arthritis, presence of calcium pyrophosphate dihydrate crystal in synovial fluid, cartilage and periarticular soft tissue and by x rays calcium deposition in articular cartilage. A family originating from Alsace, with an autosomal dominant transmission has been studied. As in English and Argentinean families, a linkage to the short arm of chromosome 5p has been found. These results suggest that a defective gene at this location may be related to the chondrocalcinosis in these families.

Adult↗
PubMed2001

[Evaluation of tolerance to endovesical BCG treatment in France: analysis of severe adverse effects notified in 3 years].

OBJECTIVES: Intravesical BCG therapy remains the first-line prophylactic treatment for recurrences of superficial bladder tumours. However, necessary the safety of this medicinal product, for which a potential risk of complications was demonstrated during development, needs to be evaluated. MATERIAL AND METHODS: Based on spontaneous notifications of adverse events reported according to good pharmacovigilance practice and in the context of a survey conducted jointly with Health Authorities, the authors present an analysis of adverse event notifications received by the manufacturer over a three-year period. A summary of serious adverse events (SAE) was established and hypotheses concerning factors predisposing to these adverse events were discussed. Finally, practice guidelines were formulated. RESULTS: During this period, 97 SAEs were reported spontaneously, including 12 local SAEs, 12 regional SAEs and 73 systemic SAEs. 46 of the 73 systemic SAEs were suspected to be due to BCG infection, 18 were related to immune disorders and the cause of 9 SAEs could not be determined. Several hypotheses are formulated concerning the circumstances leading to the onset of these SAEs and practice guidelines are proposed. CONCLUSION: Pharmacovigilance has allowed a better understanding of the qualitative and quantitative safety of BCG-IT in France. Hypotheses concerning factors predisposing to adverse effects were formulated and practice guidelines were proposed. It is essential to continue this collaboration between practitioners, Health Authorities and the manufacturer to ensure optimal use of this medicinal product.

Adjuvants, Immunologic↗
PubMed2001

[Neuropsychology and academic achievement of epileptic children: executive-functions tests].

Children with epilepsy are exposed to learning disabilities. In young children, still not taught reading, spelling or mathematics, the standardized psychometric evaluation provides a usefull assessment tool enabling identification of the structural disturbances that will affect the learning process. For school-age children, assessment can be made in regard to the DSM IV criteria of specific learning disabilities, and within a neuropsychological framework that pays a particular attention to the executive functions.

Attention↗
PubMed2001

Cognitive function in adolescents and young adults in complete remission from benign childhood epilepsy with centro-temporal spikes.

Benign childhood epilepsy with centrotemporal spikes (BECTS) is a frequent, benign childhood epilepsy with a good prognosis. However, neuropsychological deficits have been reported during its active phase. In this study, we evaluate the long-term neuropsychological consequences of this reputedly benign epilepsy, particularly the relation between paroxysmal abnormalities and cerebral language lateralization. The neuropsychological outcomes concerning both overall cognitive and lateral hemispheric functions were studied in twenty-three adolescents and young adults in total recovery from BECTS, in thirty-three controls without any significant past neurological history and in ten adolescents and young adults with complete resolution of generalized idiopathic epilepsy (childhood absence epilepsy or CAE). Language lateralization was evaluated using classical neuropsychological procedures (dichotic listening tasks, dual-task procedure). No difference was seen in the three populations with respect to overall cognitive function: memory, language and the executive functions. Although the Performance IQ was lower in patients in remission from CAE, the results were within normal limits. However, qualitative analysis of the dual-task procedure suggested a different organizational pattern for cerebral language in adolescents and young adults in remission from BECTS as compared to controls and patients in remission from CAE. The different organization in cerebral pattern in BECTS patients appeared to be related to the initial epileptic focus as determined by the EEG and/or the sleep-recording. We discuss the relationship between the presence of paroxysmal anomalies in childhood and subtle functional lateralized hemispheric abnormalities in adulthood.

Adolescent↗
PubMed2000

Raman spectroscopy of iron to 152 gigapascals: implications for Earth's inner core

Raman spectra of hexagonal close-packed iron (varepsilon-Fe) have been measured from 15 to 152 gigapascals by using diamond-anvil cells with ultrapure synthetic diamond anvils. The results give a Gruneisen parameter gamma(0) = 1.68 (+/-0.20) and q = 0.7 (+/-0.5). Phenomenological modeling shows that the Raman-active mode can be approximately correlated with an acoustic phonon and thus provides direct information about the high-pressure elastic properties of iron, which have been controversial. In particular, the C(44) elastic modulus is found to be lower than previous determinations. This leads to changes of about 35% at core pressures for shear wave anisotropies.

Journal Article↗
PubMed2000

40K-(40)Ar constraints on recycling continental crust into the mantle

Extraction of potassium into magmas and outgassing of argon during melting constrain the relative amounts of potassium in the crust with respect to those of argon in the atmosphere. No more than 30% of the modern mass of the continents was subducted back into the mantle during Earth's history. It is estimated that 50 to 70% of the subducted sediments are reincorporated into the deep continental crust. A consequence of the limited exchange between the continental crust and the upper mantle is that the chemistry of the upper mantle is driven by exchange of material with the deep mantle.

Journal Article↗