Biomedical subjects

P Simon

Publications and source records attributed to P Simon.

At least 19 recordsLinked to original sources

PubMed2006

[Hereditary pancreatitis].

Hereditary pancreatitis should be assumed if other risk factors for the disease can not been identified and if the patient has a family history for recurrent pancreatitis, chronic pancreatitis or pancreatic cancer. Since patients with chronic pancreatitis due to mutations in the cationic trypsinogen-gene have a much higher lifetime risk of developing pancreatic cancer, specifically if they are smokers, an adequate long-term follow up in specialized centers is recommended. The most frequent genetic changes in patients with hereditary pancreatitis are mutations in the cationic trypsinogen gene. Mutations in the CFTR-gene or SPINK1-gene have been reported in patients with idiopathic pancreatitis. The clinical relevance and the therapeutic consequences of these mutations is still controversial. Genetic testing is recommended when a patient with idiopathic pancreatitis is under 25 years at diagnosis or when one or more family members have either pancreatitis or pancreatic cancer. Genetic analysis of asymptomatic family members should only be offered after adequate genetic counselling. Prenatal diagnostic is not recommended.

Adult↗

PubMed2006

Kinin-dependent hypersensitivity reactions in hemodialysis: metabolic and genetic factors.

Although the association of angiotensin I-converting enzyme inhibitors (ACEis) with a negatively charged membrane is thought to be responsible for hypersensitivity reactions (HSRs) during hemodialysis, we hypothesize that these complications are due to changes in plasma aminopeptidase P (APP) activity and genotype. To test this hypothesis, we measured plasma APP activity in 14 patients who suffered HSR (HSR+) while dialyzed with an AN69 membrane and simultaneously treated with an ACEi. APP activity was also studied in a control group (n=39) dialyzed under the same conditions, but who did not suffer any side effect (HSR-). We found significantly decreased plasma APP activity (P=0.013) in HSR+ subjects as well as altered degradation of endogenous des-Arginine(9)-bradykinin, with a significantly lower beta value (P<0.001). The same analytical approach was taken in 171 relatives of HSR+ patients. Variance component analysis suggested that genetic differences may explain 61% of the phenotypic variability of plasma APP activity (P<0.001) and the kinetic parameters that characterized kinin degradation. We also showed that the C-2399A single-nucleotide polymorphism at the XPNPEP2 locus was a significant predictor of APP activity in the 39 HSR- controls (P=0.029). Furthermore, a recessive genetic model for the A allele disclosed a significant difference in mean APP activity by genotype (P<0.001). Finally, our study defined the nonspecific inhibition of recombinant APP by some ACEis. In conclusion, this paper highlights the complexity of HSR in hemodialysis, suggesting, as with angioedema, that these rare, but life-threatening adverse events are governed by several metabolic and genetic factors.

Adult↗

PubMed2006

Anomalous increase in carbon capacitance at pore sizes less than 1 nanometer.

Carbon supercapacitors, which are energy storage devices that use ion adsorption on the surface of highly porous materials to store charge, have numerous advantages over other power-source technologies, but could realize further gains if their electrodes were properly optimized. Studying the effect of the pore size on capacitance could potentially improve performance by maximizing the electrode surface area accessible to electrolyte ions, but until recently, no studies had addressed the lower size limit of accessible pores. Using carbide-derived carbon, we generated pores with average sizes from 0.6 to 2.25 nanometer and studied double-layer capacitance in an organic electrolyte. The results challenge the long-held axiom that pores smaller than the size of solvated electrolyte ions are incapable of contributing to charge storage.

Journal Article↗

PubMed2006

Tissue microarrays: applications in urological cancer research.

Tissue microarrays (TMAs) are used to simultaneously study the expression of proteins in hundreds of tissue samples, offering the important advantage to screen large tissue banks for biomarker expression and to simultaneously examine serial sections obtained from the same tumor specimen by a time- and cost-effective analytical approach. This review article presents an overview of the importance and the impact of this technique in cancer research with increasing number of investigations using TMAs in its eighth anniversary. Its application, limitations, and selected previous study results regarding urologic malignancies are presented and discussed.

Biomarkers, Tumor↗

PubMed2006

High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery applications.

All battery technologies are known to suffer from kinetic problems linked to the solid-state diffusion of Li in intercalation electrodes, the conductivity of the electrolyte in some cases and the quality of interfaces. For Li-ion technology the latter effect is especially acute when conversion rather than intercalation electrodes are used. Nano-architectured electrodes are usually suggested to enhance kinetics, although their realization is cumbersome. To tackle this issue for the conversion electrode material Fe3O4, we have used a two-step electrode design consisting of the electrochemically assisted template growth of Cu nanorods onto a current collector followed by electrochemical plating of Fe3O4. Using such electrodes, we demonstrate a factor of six improvement in power density over planar electrodes while maintaining the same total discharge time. The capacity at the 8C rate was 80% of the total capacity and was sustained over 100 cycles. The origin of the large hysteresis between charge and discharge, intrinsic to conversion reactions, is discussed and approaches to reduce it are proposed. We hope that such findings will help pave the way for the use of conversion reaction electrodes in future-generation Li-ion batteries.

Journal Article↗

PubMed2006

3-Hydroxybenzo[a]pyrene in the urine of smokers and non-smokers.

The people studied were male volunteers without occupational and dietary exposure to PAH: 27 smokers (10 cigarettes or more) and 27 non-smokers matched for age and socio-professional category. For each person, all the 24h voided urine samples were reassembled in a single sample. 1-Hydroxypyrene (1-OHPy) and 3-hydroxybenzo[a]pyrene (3-OHBaP) were then determined by automated column-switching high-performance liquid chromatography. Urinary 1-OHPy ranged from 0.041 to 0.530 micromol/molCreatinine (arithmetic mean 0.144, median 0.115) for smokers and from 0.01 to 0.148 mmol/molCreatinine (arithmetic mean 0.044, median 0.032) for non-smokers. These values are close to those of some other studies. Urinary 3-OHBaP ranged from <0.01 to 0.084 nmol/molCreatinine (arithmetic mean 0.030, median 0.023) for smokers and from <0.01 to 0.045 nmol/molCreatinine (arithmetic mean 0.014, median 0.011) for non-smokers. Considering more particularly the urinary 3-OHBaP values, the influence of smoking could be important among workers exposed to low levels of BaP (<100 ng/m(3)) and the concentrations for smokers were equivalent to most of the preshift values of exposed workers. The dietary BaP intake was slightly lower than the BaP intake for an average smoker. From the present study, temporary basic reference levels may be proposed for urinary 3-OHBaP.

Adult↗

PubMed2006

[Plate fixation with locking screw for distal fractures of the radius].

PURPOSE OF THE STUDY: Fractures of the distal radius are common. No one implant has demonstrated superior efficacy in terms of maintaining the reduction over time. We report our experience with plate fixation using a locking screw. MATERIAL AND METHODS: Between September 2003 and June 2004, 67 displaced fractures of the distal radius were treated by plate fixation using the LCP-DRP 2.4 (Synthès). Three different plates (anterior, posterior, and external) were used. The patients wore a removable anatomic brace for three weeks. Self-controlled rehabilitation exercises began directly after surgery with mobilization of the digital chains. The Fernandez, Castaing and AO classifications were noted. Ulnar variance, anteversion of the radial glenoid, radial slope and the alpha angle were measured intraoperatively and at last follow-up to assess maintenance of reduction over time. The DASH test and Green and O'Brien and PRWE scores were used to assess clinical outcome. RESULTS: Mean follow-up was eight months. Mean age was 55.8 years. Eight patients were lost to follow-up. The analysis included 59 patients who could respond to the questionnaires. Bone healing was achieved at six weeks. There were no cases of secondary displacement nor loss of reduction. The Green and O'Brien score was good or very good for 85%. The mean DASH was 20.6 and the mean PRWE 32.8. DISCUSSION: The appropriate fixation method for distal fractures of the radius remains a controversial issue, leading to a variety of materials and fixation methods. Primary stability achieved with the locking screw in a plate enables early mobilization associated with more rapid recovery of function. The absence of secondary displacement, irrespective of the quality of the underlying bone enabled us to achieve equivalent results in young patients and older patients with osteoporotic bone. This study also confirmed the preference for the anterior approach, irrespective of the direction of the displacement. To date, no other material has enabled equivalent results. This is a major achievement in terms of fixation stability.

Adult↗

PubMed2006

The use of nutritional supplements among master athletes.

We assessed the use of nutritional supplements among master athletes focusing on their source of information and source of supply of nutritional supplements. 1560 standardized, anonymous questionnaires were distributed among participants of the World Masters Athletics Championships Indoors 2004. These questions were related to biometric parameters, social indicators, training parameters, illicit drugs, and nutritional supplements. Chi2-tests were computed to reveal meaningful associations between basic information (age, gender, family status, children, education, country of origin, disciplines, training years, smoking, and the use of alcohol, illicit drugs, and doping) and the intake of nutritional supplements. Descriptive information on the history of their use of nutritional supplements was also provided. 60.5 % of all participants reported the actual use of nutritional supplements. We found no significant differences between nutritional supplement users and non-users with regard to basic information. The substances predominantly used were vitamins (35.4 %) and minerals (29.9 %). In contrast to elite athletes who use nutritional supplements to increase their athletic performance, master athletes use these substances predominantly for health reasons and, thus, have a closer contact to the health care system. Physicians are their preferred source of information about nutritional supplements. More than half of the interviewed athletes obtain their nutritional supplements from pharmacies or physicians. The results of this study indicate that nutritional supplement users in master athletics show no specific user profile. Since it is not rare for nutritional supplements to contain trace contaminations of anabolic androgenic steroids or pro-hormones, physicians should also inform master competitive athletes of the dangers of testing positive for doping substances due to their intake of nutritional supplements and advise them accordingly.

Adult↗

PubMed2006

Integration of zinc oxide nanoparticles into transparent poly(butanediolmonoacrylate) via photopolymerisation.

A new method for the preparation of transparent ZnO/PBDMA nanocomposites (PBDMA = poly(butanediolmonoacrylate)) is reported. Zinc oxide nanocrystals (4-10 nm) were synthesized in ethanol and then transferred into butanediolmonoacrylate (BDMA) to obtain a transparent and stable colloidal suspension. No further growth or aggregation of the particles could be observed, after dispersing the particles in the monomer. Effective size control in the range of 6-10 nm and concentrations up to 10 wt% zinc oxide were demonstrated for these systems. The particles and suspensions were characterized by transmission electron microscopy, X-ray diffraction, UV-VIS spectroscopy and dynamic light scattering. The addition of trimethylolpropane triacrylate (TMPTA) and a photoinitiator to the ZnO/BDMA suspension lead to a UV-curable liquid. Photoinduced polymerization was used to produce transparent nanocomposites containing the nanoparticles. The material exhibits a strong UV absorption below 360 nm, a high transmission (90%) in the visible spectral range and a green photoluminescence.

Acrylates↗

PubMed2006

[Screening for cervical cancer].

Cervical cancer incidence and mortality are falling off since the introduction of pap smear in the early 60's. In Belgium, however, there is no controlled screening politics. Oncogenic papillomaviruses are implicated in cervical cancer. Their identification is possible on thin layer technique, which allows the clinician to adapt his follow-up whether they are present or not, notably in case of borderline or low grade lesions. Cervical cancer is progressing slowly, the peak incidence happening more or less ten years after first lesions. Therefore, screening starting age, frequency and ending age are still debated. In Belgium, it is still not organised and may miss the most exposed populations. Furthermore, screening frequency is decreasing rapidly after age of 50 even though there is another incidence peak of cervical cancer at the age of 70. Pap smears' evolution in Belgium is unsure since there will be soon HPV vaccines available. But these will not be active against all oncogenic types and though they will be given to young girls before their first sexual experiences, the rest of the female population will require pap smear for a few years.

Belgium↗

PubMed2006

[Anti-HPV vaccination: preventing cervical cancer].

Two anti-HPV vaccine will soon be registered on the Belgian market. Providing immunity against the L1 protein of several oncogenic types of Papilloma virus, they aim at protecting against cervical cancer and several precancerous lesions. It has been known for years that oncogenic HPV infection of the uterine cervix is a prerequisite to the development of cervical cancer. This is supported by epidemiological has well as biological observations. That is why vaccines against capsid protein of these viruses had been developed. Two of these vaccines are about to be registered in Belgium. Cervarix (GSK) is directed against HPV 16 and 18 which are associated to ca 70% of the cervical cancers in the world. Gardasil (Sanofi Pasteur MSD) propose a vaccination against L1 protein of HPV 16 and 18, but also against HPV 6 and 11 which are responsible of benign lesions of the ano genital area (condylomas). The results obtained so far are very promising considering their preventive efficacy on persistant infections and cervical dysplasias. Two recent publications must be discussed: first, the protection offered by Cervarix is maintained for 4.5 years at least, second, vaccination by Gardasil of patients already infected by one of the HPV types (16, 18, 6, 11) provides a 100% efficacy in preventing diseases caused by the remaining types. It is therefore probable that HPV vaccination will not only concerns naive patients from any contact with HPV but also patients having already be in contact with these viruses.

Female↗

PubMed2005

SPE-GC-MS for the sampling and determination of unmetabolized styrene in urine.

The urinary excretion of unmetabolized styrene can be a very good indicator for biomonitoring styrene in occupationally exposed people. The use of a new urine sampling system, involving a solid-phase extraction cartridge, offers several advantages for determining styrene. The advantages are especially related to the pre-analytical phase of styrene determination, which may be influenced by many variables. The effect on styrene recovery of sorbent type, eluting solvent, elution volume, elution flow-rate, and the addition of methanol to the washing solvent, was evaluated by experimental design methodology. As a result, Oasis HLB cartridges were selected for urine sampling, as well as 1.5 mL of ethyl acetate at 0.5 mL/min for eluting the retained styrene. These conditions were then applied to the validation of the solid-phase extraction combined with GC-MS method for the sampling and analysis of unmetabolized styrene in urine. The overall uncertainty was in the 12-22% range and the limit of detection was 2.2 microg/L for a 4 mL urine sample. The stability of styrene has been studied both in cartridges and in vials under different storage periods. After 1 month period the styrene stored on cartridges at room temperature remained stable, whereas this is not the case for styrene recovery from vials. The results obtained indicate that on-site solid-phase extraction of urine can provide a simple, accurate and reproducible sampling and analytical method for the biomonitoring of styrene in urine.

Chromatography, Liquid↗

PubMed2005

Exotic Kondo effect from magnetic trimers.

Motivated by the recent experiments of Jamneala et al. [Phys. Rev. Lett. 87, 256804 (2001)] by combining ab initio and renormalization group methods, we study the strongly correlated state of a Cr trimer deposited on gold. Internal orbital fluctuations of the trimer lead to a huge increase of T(K) compared to the single ion Kondo temperature explaining the experimental observation of a zero-bias anomaly for the trimers. The strongly correlated state seems to belong to a new yet hardly explored class of non-Fermi-liquid fixed points.

Journal Article↗

PubMed2005

Complete cystic fibrosis transmembrane conductance regulator gene sequencing in patients with idiopathic chronic pancreatitis and controls.

BACKGROUND: Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene-many of which cause cystic fibrosis-have also been reported in patients with chronic pancreatitis. The authors examine whether mild or severe CFTR mutations, homozygous or compound heterozygous CFTR mutations, or even simple cystic fibrosis carrier status alone increases the risk of developing pancreatitis. METHODS: After exclusion of patients with trypsinogen (PRSS1) mutations, cystic fibrosis, or pulmonary disease, and with known risk factors for pancreatitis 67 patients with idiopathic chronic pancreatitis (ICP) from northwest Germany and 60 geographically and ethnically matched controls were recruited. The entire coding region of the CFTR gene was sequenced in all patients and controls. ICP patients were also analysed for serine protease inhibitor Kazal type 1 (SPINK1) gene mutations. RESULTS: Abnormal CFTR alleles were found to be twice as frequent in ICP patients as in controls (25/134 v 11/120; p<0.05). Three of four severe CFTR mutations detected in patients were compound heterozygous with another abnormal CFTR allele, whereas among controls three severe CFTR mutations were found in heterozygous cystic fibrosis carriers. In ICP patients 19 uncommon/mild mutations, including combinations of the 5T allele with 12TG repeats, were identified compared with only five in controls (p = 0.012). Heterozygous SPINK1 mutations were detected in eight ICP patients (15% v 1% in controls) but only one also carried an additional mild CFTR mutation. CONCLUSIONS: These data show that not only compound heterozygosity, but also cystic fibrosis carrier status for different types of CFTR mutations, including uncommon/mild mutations, significantly increase the risk of developing pancreatitis. Although 45% of the study's ICP patients carried predisposing genetic risk factors (for example, mutations in CFTR or SPINK1), the authors found no evidence that the risk conveyed by CFTR mutations depends on co-inherited SPINK1 mutations.

Adolescent↗

PubMed2005

Diminished production of proinflammatory cytokines in patients with Alzheimer's disease.

Cerebral inflammation as well as systemic immunological alterations have been reported in Alzheimer's disease (AD). We examined the production of the proinflammatory cytokines interleukin-6, interleukin-12, interferon-gamma, and tumor necrosis factor-alpha in whole blood cell cultures of AD patients and age-matched controls. The production of all measured cytokines after mitogen stimulation is significantly decreased in the AD group compared to controls. The results reflect an attenuated secretory activity of monocytes/macrophages, but also of T-helper cells. The data sustain the assumption that a systemic, possibly age-related alteration of immune mechanisms may play a pathogenetic role in the development of AD.

Aged↗

PubMed2005

[Rupture of the flexor tendons on an anterior plate for distal radial fracture: four cases and a review of the literature].

We report four cases of flexor tendon ruptures which occurred after distal radial fracture and reviewed the 25 other cases reported in the literature since 1932. Analysis of these 29 cases disclosed the causes of these ruptures. A deformed callus after distal radial fracture or presence of an anterior osteosynthesis plate can under certain conditions lead to secondary flexor tendon tears. It was also found that tears of the flexor pollicis longus rupture predominate, followed by injury to the flexor digitorum profundis and superficialis of the index finger. Other tendons have only been involved in only a few cases. In order to avoid this complication, we propose systematic removal of anterior plates or secondary replacement if the reduction is not totally anatomic. Surgeons should recall the importance of anatomic reduction of distal radial fractures.

Aged↗

PubMed2005

[Clear-cell sarcoma of tendons and aponeuroses: three case reports].

Clear-cell sarcoma (CCS) of tendons and aponeuroses is a rare malignant tumor representing about 1% of soft tissue tumors. Preferentially observed in young adults in the second or third decade, the tumor generally develops in the limbs. Only 2% of SCC of tendons and aponeuroses have been reported in children less than 10 years of age. This slowly progressive tumor usually forms a painless mass. The tumor increases in size followed by metastatic dissemination to lymph nodes and the lungs. The prognosis is related to tumor size. At the present time, the recognized limit is greater than 5 cm. Early diagnosis must be achieved to enable effective treatment by carcinological surgical resection. We report the three cases of CCS of tendons and aponeuroses observed at the Strasbourg University hospital over a 35-year period. Each case had a special clinical presentation. The first patient, treated in 1967, presented tumor bone lysis on the plain x-ray, an observation rarely reported in the literature. In the second patient, treated in 2002, the tumor was discovered after trauma. This patient developed skin ulceration associated with paraplegia secondary to metastatic thoracic cord compression. The third case occurred in a 12-year-old girl, treated in 2002.

Adult↗

PubMed2005

[Not Available].

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Journal Article↗