Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 20 de 209
Filtrer
1.
Mult Scler J Exp Transl Clin ; 10(1): 20552173231226106, 2024.
Article de Anglais | MEDLINE | ID: mdl-38222025

RÉSUMÉ

Background: Siponimod is approved for use in people with secondary progressive multiple sclerosis (pwSPMS). An integrated digital platform, MSGo, was developed for pwSPMS and clinicians to help navigate the multiple steps of the pre-siponimod work-up. Objective: To explore real-world onboarding experiences of siponimod amongst pwSPMS in Australia. Methods: Retrospective, non-interventional, longitudinal, secondary analysis of data extracted from MSGo (20 April 2022). The primary endpoint was the average time for siponimod onboarding; secondary endpoints were adherence and sub-group analyses of variables influencing onboarding. Results: Mixed-cure modelling estimated that 58% of participants (N = 368, females 71%, median age of 59 years) registered in MSGo would ever initiate siponimod. The median time to initiation was 56 days (95% CI [47-59] days). Half of the participants cited 'waiting for vaccination' as the reason for initiation delay. Cox regression analyses found participants with a nominated care partner had faster onboarding (HR 2.1, 95% CI [1.5-3.0]) and were more likely to continue self-reporting daily siponimod dosing than were those without a care partner (HR 2.2, 95% CI [1.3-3.7]). Conclusions: Despite the limitations of self-reported data and the challenges of the COVID-19 pandemic, this study provides insights into siponimod onboarding in Australia and demonstrates the positive impact of care partner support.

2.
Behav Brain Res ; 399: 112974, 2021 02 05.
Article de Anglais | MEDLINE | ID: mdl-33144178

RÉSUMÉ

Animals organize reward seeking around aversive events. An abundance of research shows that foot shock, as well as a shock-associated cue, can elicit freezing and suppress reward seeking. Yet, there is evidence that experience can flip the effect of foot shock to facilitate reward seeking. Here we examined cue suppression, foot shock suppression and foot shock facilitation of reward seeking in a single behavioural setting. Male Long Evans rats received fear discrimination consisting of danger, uncertainty, and safety cues. Discrimination took place over a baseline of rewarded nose poking. With limited experience (1-2 sessions), all cues and foot shock suppressed reward seeking. With continued experience (10-16 sessions), suppression became specific to shock-associated cues, foot shock briefly suppressed, then facilitated reward seeking. Our results provide a means of assessing positive properties of foot shock, and may provide insight into maladaptive behaviour around aversive events.


Sujet(s)
Comportement animal/physiologie , Apprentissage discriminatif/physiologie , Peur/physiologie , Récompense , /physiologie , Animaux , Signaux , Stimulation électrique , Mâle , Rats , Rat Long-Evans
3.
Ann Oncol ; 24(4): 924-30, 2013 Apr.
Article de Anglais | MEDLINE | ID: mdl-23233650

RÉSUMÉ

BACKGROUND: This phase II, open-label, multicentre study aimed to evaluate changes in cell proliferation and biomarkers, as well as efficacy of lapatinib in treatment-naïve patients with HER-2-negative primary breast cancer. PATIENTS AND METHODS: Patients received 1500 mg lapatinib for 28-42 days before surgery with repeat biopsies and measurements. The primary end point was inhibition of cell proliferation measured by Ki67; the secondary end points included clinical response, adverse events and changes in FOXO3a, FOXM1, p-AKT and HER-3. RESULTS: Overall, there was no significant reduction in Ki67 with treatment (assessment carried out in 28 of 31 subjects enrolled). However, four patients (14%) showed a reduction in Ki67 ≥50%. Four of 25 patients (16%) had a partial response to treatment judged by sequential ultrasound measurements. Response, in terms of either Ki67 or ultrasound, did not relate to changes in any biomarker assessed at baseline, including the estrogen receptor (ER) and epidermal growth factor receptor (EGFR). However, all four clinical responders were HER-3 positive, as were three of four Ki67 responders. CONCLUSIONS: Overall, a pre-surgical course of lapatinib monotherapy had little effect on this group of patients; however, in subsets of patients, especially those with HER-3-positive tumors, we observed either reduction in proliferation (Ki67) or tumor size; EGFR/ER status had no impact.


Sujet(s)
Tumeurs du sein/traitement médicamenteux , Prolifération cellulaire/effets des médicaments et des substances chimiques , Régulation de l'expression des gènes tumoraux/effets des médicaments et des substances chimiques , Quinazolines/administration et posologie , Adulte , Sujet âgé , Biopsie , Tumeurs du sein/génétique , Tumeurs du sein/anatomopathologie , Récepteurs ErbB/métabolisme , Femelle , Protéine M1 à motif en tête de fourche , Protéine O3 à motif en tête de fourche , Facteurs de transcription Forkhead/métabolisme , Humains , Antigène KI-67/métabolisme , Lapatinib , Adulte d'âge moyen , Protéine oncogène v-akt/métabolisme , Récepteur ErbB-2/génétique , Récepteur ErbB-3/métabolisme , Récepteurs des oestrogènes/métabolisme
4.
J Clin Pathol ; 64(8): 649-53, 2011 Aug.
Article de Anglais | MEDLINE | ID: mdl-21690244

RÉSUMÉ

These guidelines supplement existing guidelines on HER2 testing by immunohistochemistry and in-situ hybridisation(ISH) methods in the UK. They provide a specific focus on aspects of guidance relevant to HER2 ISH testing methods, both fluorescent and chromogenic. They are formulated to give advice on methodology, interpretation and quality control for ISH-based testing of HER2 status in common tumour types, including both breast and gastric tumours. The aim is to ensure that all ISH-based testing is accurate, reliable and timely.


Sujet(s)
Tumeurs du sein/diagnostic , Hybridation in situ/méthodes , Récepteur ErbB-2/métabolisme , Tumeurs de l'estomac/diagnostic , Tumeurs du sein/génétique , Femelle , Gènes erbB-2 , Humains , Hybridation in situ/normes , Formation en interne , Corps médical/enseignement et éducation , Techniques de sonde moléculaire , Assurance de la qualité des soins de santé , Contrôle de qualité , Plan de recherche , Manipulation d'échantillons , Tumeurs de l'estomac/génétique
5.
Br J Cancer ; 104(8): 1342-8, 2011 Apr 12.
Article de Anglais | MEDLINE | ID: mdl-21427727

RÉSUMÉ

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is amplified and overexpressed in 20-25% of breast cancers. This study investigated circulating free DNA (cfDNA) for detection of HER2 gene amplification in patients with breast cancer. METHODS: Circulating free DNA was extracted from plasma of unselected patients with primary breast cancer (22 before surgery and 68 following treatment), 30 metastatic patients and 98 female controls using the QIAamp Blood DNA Mini Kit (Qiagen). The ratio of HER2 to an unamplified reference gene (contactin-associated protein 1 (CNTNAP1)) was measured in cfDNA samples by quantitative PCR (qPCR) using SK-BR-3 cell line DNA as a positive control. RESULTS: We validated the qPCR assay with DNA extracted from 23 HER2 3+ and 40 HER2-negative tumour tissue samples; the results agreed for 60 of 63 (95.2%) tumours. Amplification was detected in cfDNA for 8 of 68 patients following primary breast cancer treatment and 5 of 30 metastatic patients, but was undetected in 22 patients with primary breast cancer and 98 healthy female controls. Of the patients with amplification in cfDNA, 10 had HER2 3+ tumour status by immunohistochemistry. CONCLUSIONS: The results demonstrate for the first time the existence of amplified HER2 in cfDNA in the follow-up of breast cancer patients who are otherwise disease free. This approach could potentially provide a marker in patients with HER2-positive breast cancer.


Sujet(s)
Tumeurs du sein/génétique , Carcinomes/génétique , ADN/sang , Amplification de gène , Récepteur ErbB-2/génétique , Tumeurs du sein/sang , Tumeurs du sein/métabolisme , Tumeurs du sein/anatomopathologie , Carcinomes/sang , Carcinomes/métabolisme , Carcinomes/anatomopathologie , Études cas-témoins , Lignée cellulaire tumorale , ADN/analyse , Analyse de mutations d'ADN , Femelle , Études de suivi , Humains , Métastase tumorale , Phénotype , Récepteur ErbB-2/sang , Récepteur ErbB-2/métabolisme , Études rétrospectives
6.
Breast Cancer Res Treat ; 114(1): 63-9, 2009 Mar.
Article de Anglais | MEDLINE | ID: mdl-18368476

RÉSUMÉ

In a previous investigation reduced apoptosis was identified in normal breast tissue from cancer-containing breasts away from the cancer in comparison to age-matched normal breast from women without cancer. The hypothesis for this study was that defects in expression of apoptotic regulatory and DNA repair proteins would facilitate persistence of genetic alterations and predispose to breast cancer development. Using immunohistochemistry normal breast from 120 age-matched women (58 with breast cancer, 62 without) was analysed for proliferation, apoptosis, bcl2, BAX, caspase 3, Hsp27, Hsp70, BRCA1, ATM and BARD1. All assessments were performed without knowledge as to whether it was a cancer case or control. A significant difference was found for apoptotic index which was higher in controls (P < 0.02). There was no change in apoptotic and proliferation index with age for cancer cases unlike controls. Higher expression of bcl2 (P = 0.001) and Hsp27 (P = 0.001) was found in normal breast from cancer-containing breast in comparison to controls. There were no differences in the other proteins. Apoptosis has been found to be reduced in normal breast in a separate cohort of women with breast cancer, along with increased expression of the anti-apoptotic proteins bcl2 and Hsp27. These alterations in apoptotic regulation would enhance tumour development. Further studies are needed to examine the value of these proteins as risk markers.


Sujet(s)
Protéines régulatrices de l'apoptose/génétique , Tumeurs du sein/génétique , Adulte , Protéines régulatrices de l'apoptose/biosynthèse , Marqueurs biologiques tumoraux , Région mammaire/anatomopathologie , Tumeurs du sein/métabolisme , Tumeurs du sein/anatomopathologie , Femelle , Expression des gènes , Prédisposition génétique à une maladie , Humains , Immunohistochimie , Adulte d'âge moyen
7.
J Clin Pathol ; 61(7): 818-24, 2008 Jul.
Article de Anglais | MEDLINE | ID: mdl-18381380

RÉSUMÉ

These guidelines update the previous UK HER2 testing guidelines and have been formulated to give advice on methodology, interpretation and quality assurance to ensure that HER2 testing results are accurate, reliable and timely with the expansion of testing to all patients with breast cancer at the time of primary diagnosis. The recommendations for testing are the use of immunohistochemistry but with analysis of equivocal cases by in situ hybridisation to clarify their HER2 status or the use of frontline fluorescence in situ hybridisation (FISH) testing for those laboratories wishing to do so; the inclusion of a chromosome 17 probe is strongly recommended. Laboratories using chromogenic or silver in situ hybridisation should perform an initial validation against FISH. For immunohistochemistry and in situ hybridisation there must be participation in the appropriate National External Quality Assurance scheme.


Sujet(s)
Marqueurs biologiques tumoraux/métabolisme , Tumeurs du sein/diagnostic , Gènes erbB-2 , Récepteur ErbB-2/métabolisme , Tumeurs du sein/génétique , Tumeurs du sein/métabolisme , Femelle , Humains , Immunohistochimie , Hybridation fluorescente in situ/méthodes , Assurance de la qualité des soins de santé , Manipulation d'échantillons/méthodes , Manipulation d'échantillons/normes
8.
J Clin Pathol ; 61(6): 689-96, 2008 Jun.
Article de Anglais | MEDLINE | ID: mdl-18037665

RÉSUMÉ

Breast cancer is the predominant malignancy where oncologists use predictive markers clinically to select treatment options, with steroid receptors having been used for many years. Immunohistochemistry has taken over as the major assay method used for assessing markers. Despite its extensive use there are still issues around tissue fixation, methodology, interpretation and quantification. Although many markers have been evaluated, the oestrogen receptor remains the most reliable and best example of a predictor of treatment response. It is of major importance clinically that those undertaking interpretation of predictive markers understand the technical pitfalls and are aware of how expression of a particular marker relates to breast cancer pathology. A false negative or a false positive result will impact on patient management.


Sujet(s)
Marqueurs biologiques tumoraux/analyse , Tumeurs du sein/diagnostic , Récepteurs des oestrogènes/analyse , Tumeurs du sein/traitement médicamenteux , Femelle , Humains , Immunohistochimie , Sélection de patients , Pronostic , Récepteurs à la progestérone/analyse , Fixation tissulaire/méthodes
9.
J Colloid Interface Sci ; 311(2): 587-94, 2007 Jul 15.
Article de Anglais | MEDLINE | ID: mdl-17448492

RÉSUMÉ

Irganox 1076 (IN1076) and Irganox 1010 (IN1010), phenol containing species often used as antioxidant additives in food packaging polymers have both hydrophilic and hydrophobic functional groups. Consequently these additives are likely to absorb to surfaces where their free energy is minimized. Experiments described in this work examine the two-dimensional phase behavior and vibrational structure of IN1076 and IN1010 films adsorbed to the air/water interface. Surface pressure isotherms show that repeated compression of these films leads to continued irreversible loss of molecules and that on a per molecule basis, this loss is more pronounced for IN1076 than for IN1010. Differences in the surface properties of these two antioxidant additives are interpreted based on differences in molecular structure. Surface specific vibrational measurements of these organic films show very little conformational order, implying that even when closely packed, both antioxidant species have little affinity for forming highly organized domains. These findings have important ramifications for mechanisms that reduce antioxidant activity in polymers as well as descriptions of antioxidant blooming on polymer surfaces.


Sujet(s)
Additifs alimentaires/composition chimique , Polymères/composition chimique , Tension superficielle , Antioxydants/composition chimique , Butylhydrotoluène/analogues et dérivés , Phénols , Spectrophotométrie IR
10.
Br J Cancer ; 96(4): 639-45, 2007 Feb 26.
Article de Anglais | MEDLINE | ID: mdl-17285125

RÉSUMÉ

Established clinico-pathological factors can place patients with breast cancer into good and poor prognostic categories, but even within these groups behaviour and response to treatment can differ. This study examined the value of cell cycle and apoptotic regulatory proteins in predicting behaviour in a poor prognostic group. A total of 165 patients, all of whom had died of breast cancer with duration of survival 12-127 months, median 38 months, were examined using immunohistochemistry for proliferation, apoptosis, p53, phosphorylated p53, p21, checkpoint kinase 2 (Chk2), bcl-2, bax, survivin and XIAP. All had received chemotherapy and/or hormonal therapy and were predominantly T2, node positive, grade III with only half oestrogen-receptor (ER) positive. High proliferation, phosphorylated p53, Chk2 and survivin expression correlated with grade III and lack of ER, whereas low proliferation, p21 and bcl-2 related to better grade and presence of ER. On univariate analysis grade, proliferation, phosphorylated p53, bcl-2, ER and survivin related to duration of survival. In multivariate analysis, grade (P=0.001) and survivin (P=0.005) were independent prognostic factors, grade III and presence of survivin relating to shorter survival. The latter was particularly for those patients receiving neoadjuvant therapy and adjuvant chemo- and hormonal therapy. The presence of the inhibitor of apoptosis protein survivin is a highly significant independent predictor of shorter duration of survival of patients with poor prognostic features, and merits investigation as a marker in other prognostic groups.


Sujet(s)
Tumeurs du sein/diagnostic , Tumeurs du sein/métabolisme , Protéines associées aux microtubules/métabolisme , Protéines tumorales/métabolisme , Adulte , Sujet âgé , Apoptose , Tumeurs du sein/thérapie , Cycle cellulaire , Prolifération cellulaire , Traitement médicamenteux adjuvant , Femelle , Humains , Protéines IAP , Adulte d'âge moyen , Analyse multifactorielle , Valeur prédictive des tests , Pronostic , Récepteur ErbB-2/métabolisme , Récepteurs des oestrogènes/métabolisme , Analyse de survie , Survivine , Protéine p53 suppresseur de tumeur/métabolisme
11.
J Pathol ; 211(2): 232-40, 2007 Jan.
Article de Anglais | MEDLINE | ID: mdl-17200937

RÉSUMÉ

There is a clear association between the development of breast cancer and increasing age, with 80% of cancers occurring in women more than 50 years of age and one-third in women over 70 years. Following the menopause the breast undergoes involution, with the main changes affecting the terminal ductal lobular unit. There is an increase in oestrogen receptor alpha (ERalpha)-positive cells, a decrease in proliferation but, in comparison to premenopausal breasts, a greater number of ERalpha-proliferating cells. The breast cancers that occur in women >/= 75 years are more likely to be ER-positive, with a low growth rate and limited expression of HER-2 and p53. It is proposed that uneven involution of the breast, the persistence of at-risk lesions, the presence of ERalpha-proliferating cells and local oestrogen metabolism in breast adipose tissue are factors in the development of breast cancers with a well-differentiated phenotype.


Sujet(s)
Vieillissement/physiologie , Tumeurs du sein/physiopathologie , Région mammaire/physiopathologie , Tissu adipeux/physiologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Vieillissement/anatomopathologie , Région mammaire/anatomopathologie , Tumeurs du sein/étiologie , Tumeurs du sein/anatomopathologie , Épithélioma in situ/anatomopathologie , Épithélioma in situ/physiopathologie , Division cellulaire/physiologie , Récepteur alpha des oestrogènes/analyse , Femelle , Humains , Adulte d'âge moyen , Invasion tumorale/anatomopathologie , Invasion tumorale/physiopathologie , Post-ménopause/physiologie , Récepteur ErbB-2/analyse
12.
J Pathol ; 211(5): 499-506, 2007 Apr.
Article de Anglais | MEDLINE | ID: mdl-17236182

RÉSUMÉ

Oestrogen receptor (ER) is arguably the single most important biological predictive factor that exists today. In the last 10 years or so, however, our understanding of ER biology has undergone a paradigm shift following the identification of a second ER, ERbeta, with the original ER being renamed ERalpha. A number of isoforms have additionally been described, especially for ERbeta. Our knowledge of ER signalling has also increased with the recognition of accessory co-regulatory proteins, which help direct the transcriptional cascade. Here we outline these changes and discuss what biological and clinical implications these could have in the mammary gland.


Sujet(s)
Tumeurs du sein/génétique , Récepteurs des oestrogènes/physiologie , Animaux , Région mammaire/physiopathologie , Tumeurs du sein/physiopathologie , Résistance aux médicaments antinéoplasiques/physiologie , Récepteurs ErbB/physiologie , Récepteur alpha des oestrogènes/génétique , Récepteur alpha des oestrogènes/physiologie , Récepteur bêta des oestrogènes/génétique , Récepteur bêta des oestrogènes/physiologie , Femelle , Humains , Souris , Souris knockout , Phosphorylation , Récepteurs des oestrogènes/génétique , Récepteurs à la progestérone/physiologie , Transduction du signal/génétique , Transduction du signal/physiologie , Transcription génétique/génétique
13.
Histopathology ; 49(4): 406-10, 2006 Oct.
Article de Anglais | MEDLINE | ID: mdl-16978204

RÉSUMÉ

Immunohistochemistry is no longer a technique used only for research but is employed increasingly for diagnosis and for the assessment of therapeutic biomarkers. The latter, in particular, often require a semiquantitative evaluation of the extent of their presence. There are many factors that can affect this that relate to the method: fixation of tissue, duration and type of antigen retrieval, antibody specificity, antibody dilution and detection systems. Other complexities relate to assessment. Different scoring systems are used for either the same or different antigens. Cut-off levels for assessing whether a tissue is 'positive' or 'negative' can vary for the same antigen. Whilst there are quality assurance schemes for the methodology that have improved standards of staining, there are no similar schemes that relate to interpretation, although errors here can create as many problems. There have been improvements in automated analysis but availability is limited and it is still predominantly a research tool. In order for quantification of immunohistochemistry to be a reliable and reputable tool, there must be easy to use, reproducible, standardized protocols for assessment which are international. Improvements in automated analysis with wider applicability could lead to standardization.


Sujet(s)
Marqueurs biologiques/analyse , Immunohistochimie/méthodes , Immunohistochimie/normes , Anatomopathologie chirurgicale/normes , Expertise , Humains , Traitement d'image par ordinateur , Contrôle de qualité , Reproductibilité des résultats
14.
J Clin Pathol ; 59(2): 130-7, 2006 Feb.
Article de Anglais | MEDLINE | ID: mdl-16443726

RÉSUMÉ

BACKGROUND: The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology, and assess the consistency of pathology reporting of breast disease in the UK. AIMS/METHODS: To examine the performance (scores) of pathologists participating in the scheme in recent years. The scheme has evolved to help identify poor performers, reliant upon setting an acceptable cutpoint. Therefore, the effects of different cutpoint strategies were evaluated and implications discussed. RESULTS/CONCLUSIONS: Pathologists who joined the scheme improved over time, particularly those who did less well initially. There was no obvious association between performance and the number of breast cancer cases reported each year. This is not unexpected because the EQA does not measure expertise, but was established to demonstrate a common level of performance (conformity to consensus) for routine cases, rather than the ability to diagnose unusual/difficult cases. A new method of establishing cutpoints using interquartile ranges is proposed. The findings also suggest that EQA can alter a pathologist's practice: those who leave the scheme (for whatever reason) have, on average, marginally lower scores. Consequently, with the cutpoint methodology currently used (which is common to several EQA schemes) there is the potential for the cutpoint to drift upwards. In future, individuals previously deemed competent could subsequently be erroneously labelled as poor performers. Due consideration should be given to this issue with future development of schemes.


Sujet(s)
Tumeurs du sein/anatomopathologie , Assurance de la qualité des soins de santé , Médecine d'État/normes , Compétence clinique , Formation médicale continue comme sujet/méthodes , Femelle , Humains , Dépistage de masse/normes , Anatomopathologie clinique/enseignement et éducation , Anatomopathologie clinique/organisation et administration , Anatomopathologie clinique/normes , Charge de travail/statistiques et données numériques
15.
J Clin Pathol ; 59(2): 138-45, 2006 Feb.
Article de Anglais | MEDLINE | ID: mdl-16443727

RÉSUMÉ

BACKGROUND: This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology. AIMS/METHODS: The major objectives were to monitor and improve the consistency of diagnoses made by pathologists and the quality of prognostic information in pathology reports. The scheme is based on a twice yearly circulation of 12 cases to over 600 registered participants. The level of agreement was generally measured using kappa statistics. RESULTS: Four main situations were encountered with respect to diagnostic consistency, namely: (1) where consistency is naturally very high-this included diagnosing in situ and invasive carcinomas (and certain distinctive subtypes) and uncomplicated benign lesions; (2) where the level of consistency was low but could be improved by making guidelines more detailed and explicit-this included histological grading; (3) where consistency could be improved but only by changing the system of classification-this included classification of ductal carcinoma in situ; and (4) where no improvement in consistency could be achieved-this included diagnosing atypical hyperplasia and reporting vascular invasion. Size measurements were more consistent for invasive than in situ carcinomas. Even in cases where there is a high level of agreement on tumour size, a few widely outlying measurements were encountered, for which no explanation is readily forthcoming. CONCLUSIONS: These results broadly confirm the robustness of the systems of breast disease diagnosis and classification adopted by the NHSBSP, and also identify areas where improvement or new approaches are required.


Sujet(s)
Tumeurs du sein/anatomopathologie , Assurance de la qualité des soins de santé , Carcinome canalaire du sein/anatomopathologie , Carcinome intracanalaire non infiltrant/anatomopathologie , Compétence clinique , Femelle , Humains , Dépistage de masse/normes , Invasion tumorale , Pronostic , Médecine d'État/normes , Royaume-Uni
16.
Food Addit Contam ; 22(10): 1023-31, 2005 Oct.
Article de Anglais | MEDLINE | ID: mdl-16227186

RÉSUMÉ

Perfluorochemicals are widely used in the manufacturing and processing of a vast array of consumer goods, including electrical wiring, clothing, household and automotive products. Furthermore, relatively small quantities of perfluorochemicals are also used in the manufacturing of food-contact substances that represent potential sources of oral exposure to these chemicals. The most recognizable products to consumers are the uses of perfluorochemicals in non-stick coatings (polytetrafluoroethylene (PTFE)) for cookware and also their use in paper coatings for oil and moisture resistance. Recent epidemiology studies have demonstrated the presence of two particular perfluorochemicals, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in human serum at very low part per billion levels. These perfluorochemicals are biopersistent and are the subject of numerous studies investigating the many possible sources of human exposure. Among the various uses of these two chemicals, PFOS is a residual impurity in some paper coatings used for food contact and PFOA is a processing aid in the manufacture of PTFE used for many purposes including non-stick cookware. Little information is available on the types of perfluorochemicals that have the potential to migrate from perfluoro coatings into food. One obstacle to studying migration is the difficulty in measuring perfluorochemicals by routine conventional analytical techniques such as GC/MS or LC-UV. Many perfluorochemicals used in food-contact substances are not detectable by these conventional methods. As liquid chromatography-mass spectrometry (LC/MS) develops into a routine analytical technique, potential migrants from perfluoro coatings can be more easily characterized. In this paper, data will be presented on the types of perfluoro chemicals that are used in food packaging and cookware. Additionally, research will be presented on the migration or potential for migration of these chemicals into foods or food simulating liquids. Results from migration tests show mg kg(-1) amounts of perfluoro paper additives/coatings transfer to food oil. Analysis of PTFE cookware shows residual amounts of PFOA in the low microg kg(-1) range. PFOA is present in microwave popcorn bag paper at amounts as high as 300 microg kg(-1).


Sujet(s)
Polymères de fluorocarbone/composition chimique , Contamination des aliments , Emballage alimentaire , Caprylates/analyse , Chromatographie en phase liquide/méthodes , Ustensiles de cuisine et de table , Exposition environnementale/effets indésirables , Conception d'appareillage , Fluorocarbones/analyse , Articles ménagers , Humains , Micro-ondes , Papier , Polytétrafluoroéthylène/analyse , Spectrométrie de masse ESI/méthodes
17.
Faraday Discuss ; 129: 69-80; discussion 89-109, 2005.
Article de Anglais | MEDLINE | ID: mdl-15715300

RÉSUMÉ

Resonance enhanced second harmonic generation (SHG) coupled with novel solvatochromic surfactants has been used to explore solvation across liquid/liquid interfaces in the presence of excess surface charge in the aqueous phase. The surfactants--dubbed "molecular rulers"--consist of hydrophobic, solvatochromic chromophores connected to charged headgroups via variable length alkyl spacers. Interfacial dipolar width is monitored as a function of chromophore/headgroup separation. Data show that cationic and anionic surfactants of equivalent lengths sample very different environments across a water/cyclohexane interface. The effective excitation wavelengths of cationic surfactants are shifted persistently to higher energies than in bulk cyclohexane while anionic surfactants solvation converges smoothly from the aqueous to the organic limit with increasing spacer length. To further evaluate the effect of surface charge on interfacial solvation, SHG was used to probe the environment surrounding molecular ruler chromophores adsorbed to the aqueous liquid/vapor interface in the presence of densely packed monolayers of 1-octanol. These monolayer systems are shown to reproduce qualitatively many of the features associated with bulk water/alkane interfaces and are logistically easier to assemble. Changing the ionic strength of the underlying aqueous sub-phase suggests that the headgroup of cationic molecular ruler surfactants alters the electronic structure of the chromophore rather than properties of the surrounding nonpolar environment.

19.
J Antimicrob Chemother ; 53(5): 729-38, 2004 May.
Article de Anglais | MEDLINE | ID: mdl-15056636

RÉSUMÉ

OBJECTIVES: To ascertain the agreement between MICs determined at a central laboratory, and susceptible, intermediate and resistant categorizations based on zone diameters recorded at diagnostic laboratories using the BSAC standardized method. METHODS: Standardized disc susceptibility tests were performed at sentinel laboratories in three surveys, with MIC tests performed on the collected isolates at a reference laboratory. The organisms comprised over 3300 Enterobacteriaceae, Acinetobacter spp., pseudomonads, staphylococci and enterococci, with over 29 000 antibiotic/organism tests in total. RESULTS: More than 90% of the antibiotic/organism combinations classed as susceptible by disc tests in the sentinel laboratories were confirmed by MIC testing. Disagreements were more frequent where disc tests indicated resistance, with half of the piperacillin/tazobactam resistance and one-third of the cephalosporin resistance found in Enterobacteriaceae by disc tests not being confirmed, and with three-quarters of teicoplanin resistance in enterococci not confirmed. None of the few apparent cases of meropenem resistance in Enterobacteriaceae or linezolid, quinupristin/dalfopristin or vancomycin resistance in staphylococci were confirmed by MIC testing. When disagreements were found between disc- and MIC-based categorization, MICs were commonly, although not invariably, one to three doubling dilutions above or below the breakpoint. However, many of the disagreements where MICs were three or more dilutions from the breakpoint were not seen when disc tests were repeated in the central laboratory. CONCLUSIONS: The BSAC disc method seems adequate for confirming susceptibility to guide therapy and to monitor resistance trends. Nevertheless, there must be concern about the over-estimation of many resistances, and frequent zone:MIC disagreements for isolates with borderline susceptibility.


Sujet(s)
Bactéries/effets des médicaments et des substances chimiques , Tests de sensibilité microbienne/normes , Infections bactériennes/microbiologie , Collecte de données , Humains , Laboratoires , Tests de sensibilité microbienne/méthodes , Normes de référence , Reproductibilité des résultats , Royaume-Uni
20.
Int J Antimicrob Agents ; 22(6): 622-5, 2003 Dec.
Article de Anglais | MEDLINE | ID: mdl-14659662

RÉSUMÉ

Mutations in gyrA in strains of Salmonella enterica serotypes Typhi and Paratyphi A have been characterised by a LightCycler-based PCR-hybridisation gyrA mutation assay (GAMA) and by DNA sequencing. Four mutations (Ser-83 to Phe, Asp-87 to Asn, Ser-83 to Tyr and Asp-87 to Gly) have been identified in 13 strains of Typhi and three strains of Paratyphi A resistant to nalidixic acid (=nal(r)) and with decreased susceptibility to ciprofloxacin (=Cp(L)), with the mutation Ser-83 to Phe predominating. The results have demonstrated heterogeneity in gyrA in nal(r) Cp(L) strains of Typhi and Paratyphi A and may be useful for epidemiological investigations. No mutations in gyrA were identified in four Cp(L) strains of S. Typhi that were sensitive to nalidixic acid. The mechanism of decreased susceptibility to ciprofloxacin in these strains is under investigation.


Sujet(s)
Antibactériens/pharmacologie , Ciprofloxacine/pharmacologie , DNA gyrase/génétique , Mutation , Salmonella paratyphi A/effets des médicaments et des substances chimiques , Salmonella paratyphi A/génétique , Salmonella typhi/effets des médicaments et des substances chimiques , Salmonella typhi/génétique , Lysotypie , Analyse de mutations d'ADN , ADN bactérien/génétique , Résistance bactérienne aux médicaments , Gènes bactériens , Humains , Techniques in vitro , Réaction de polymérisation en chaîne/méthodes , Salmonella paratyphi A/classification , Salmonella paratyphi A/enzymologie , Salmonella typhi/classification , Salmonella typhi/enzymologie , Sérotypie
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE
...