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1.
Ann Oncol ; 34(2): 200-211, 2023 02.
Article de Anglais | MEDLINE | ID: mdl-36423745

RÉSUMÉ

BACKGROUND: Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)]. PATIENTS AND METHODS: c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961). RESULTS: Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance. CONCLUSIONS: c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.


Sujet(s)
Antinéoplasiques immunologiques , ADN tumoral circulant , Maladie résiduelle , Tumeurs du sein triple-négatives , Humains , Marqueurs biologiques tumoraux/sang , Mutation , Récidive tumorale locale/sang , Récidive tumorale locale/diagnostic , Récidive tumorale locale/traitement médicamenteux , Récidive tumorale locale/génétique , Études prospectives , Tumeurs du sein triple-négatives/sang , Tumeurs du sein triple-négatives/diagnostic , Tumeurs du sein triple-négatives/traitement médicamenteux , Tumeurs du sein triple-négatives/génétique , Maladie résiduelle/sang , Maladie résiduelle/diagnostic , Maladie résiduelle/traitement médicamenteux , Maladie résiduelle/génétique , Antinéoplasiques immunologiques/usage thérapeutique , ADN tumoral circulant/sang
2.
Eur J Surg Oncol ; 40(7): 824-9, 2014 Jul.
Article de Anglais | MEDLINE | ID: mdl-24742589

RÉSUMÉ

PURPOSE: To evaluate the efficacy of a BLES procedure as a primary excisional biopsy rather than a surgical wide local excision for treatment of a high risk or a malignant lesion. METHODS: 41 patients underwent a BLES procedure in order to attempt to remove a small breast lesion using a 15 mm or 20 mm wand from August 2007 to January 2009. The lesions were either proven on prior core biopsy to show high risk or malignant pathology or were considered to be indeterminate or suspicious on ultrasound or mammography. The pathology was reviewed to include the final status of lesion excision. If margin involvement was demonstrated then a formal surgical excision was subsequently recommended. Follow up mammography or ultrasound was performed annually in patients following the final pathological diagnosis. RESULTS: 9 patients had a primary diagnosis of atypia (columnar cell change with atypia or atypical ductal hyperplasia (ADH)), 23 patients had ductal carcinoma in situ (DCIS) and 9 had an invasive carcinoma (IC) at the original BLES pathology. Clear BLES margins of >1 mm were obtained in 3/9 atypia lesions, 15/23 DCIS and 0/9 IC. 12/13 low grade DCIS were completely excised. Subsequent surgical margin excisions were undertaken in 20 patients. After at least 5 years of follow up (mean 66 months), 1 lesion had recurred on imaging. CONCLUSION: A BLES excision has potential as an alternative technique to traditional surgical wide local excision in the management of certain small breast lesions with high risk and low grade malignant potential.


Sujet(s)
Tumeurs du sein/anatomopathologie , Tumeurs du sein/chirurgie , Carcinome canalaire du sein/anatomopathologie , Carcinome canalaire du sein/chirurgie , Carcinome intracanalaire non infiltrant/anatomopathologie , Carcinome intracanalaire non infiltrant/chirurgie , Chirurgie assistée par ordinateur/instrumentation , Adulte , Biopsie/instrumentation , Biopsie/méthodes , Biopsie au trocart/instrumentation , Biopsie au trocart/méthodes , Tumeurs du sein/imagerie diagnostique , Carcinome canalaire du sein/imagerie diagnostique , Carcinome intracanalaire non infiltrant/imagerie diagnostique , Études de cohortes , Conception d'appareillage , Sécurité du matériel , Femelle , Études de suivi , Humains , Biopsie guidée par l'image/instrumentation , Biopsie guidée par l'image/méthodes , Adulte d'âge moyen , États précancéreux/imagerie diagnostique , États précancéreux/anatomopathologie , États précancéreux/chirurgie , Radiographie , Études rétrospectives , Appréciation des risques , Sensibilité et spécificité , Techniques stéréotaxiques/instrumentation , Chirurgie assistée par ordinateur/méthodes , Facteurs temps
3.
Transpl Infect Dis ; 15(2): E64-9, 2013 Apr.
Article de Anglais | MEDLINE | ID: mdl-23387927

RÉSUMÉ

Initial presentation of invasive fungal infections such as histoplasmosis can include non-specific clinical manifestations, especially in immunocompromised patients. A high index of suspicion is required to identify atypical manifestations of these diseases, which carry a high risk of mortality, if the diagnosis is delayed or missed. We describe a case of a kidney transplant recipient with cutaneous lesions as initial manifestation of progressive disseminated histoplasmosis where a skin biopsy was crucial to an early diagnosis.


Sujet(s)
Mycoses cutanées/diagnostic , Histoplasmose/diagnostic , Transplantation rénale , Adulte , Antifongiques/usage thérapeutique , Mycoses cutanées/traitement médicamenteux , Femelle , Histoplasmose/traitement médicamenteux , Humains , Sujet immunodéprimé , Itraconazole/usage thérapeutique , Ohio , Complications postopératoires , Facteurs temps , Résultat thérapeutique ,
4.
Breast ; 22(1): 78-82, 2013 Feb.
Article de Anglais | MEDLINE | ID: mdl-22789490

RÉSUMÉ

We aim to identify preoperative factors at diagnosis which could predict whether women undergoing wide local excision (WLE) would require further operations. 1593 screen-detected invasive and non-invasive breast cancers were reviewed. Age, presence of ductal carcinoma in situ (DCIS), invasive cancer size on mammography, mammographic sign, tumour type, grade and confidence of the radiologist in malignancy were compared. 83%(1315/1593) of women had a WLE. Of these, 70%(919/1315) had a single operation, and 30%(396/1315) multiple operations. These included repeat WLE to clear margins (60%(238/396)), mastectomy (34%(133/396)) and axillary dissection (6%(25/396)). The presence of mammographic microcalcification, lobular carcinoma and grade 2 malignancy on core biopsy were independent risk factors for multiple operations on multivariate analysis. Women with mammographic DCIS >30 mm were 3.4 times more likely to undergo repeat surgery than those with smaller foci. The multidisciplinary team should pay particular attention to these factors when planning surgery.


Sujet(s)
Tumeurs du sein/chirurgie , Carcinome canalaire du sein/chirurgie , Carcinome intracanalaire non infiltrant/chirurgie , Carcinome lobulaire/chirurgie , Lymphadénectomie/statistiques et données numériques , Mastectomie/statistiques et données numériques , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Biopsie au trocart , Région mammaire/anatomopathologie , Tumeurs du sein/diagnostic , Carcinome canalaire du sein/imagerie diagnostique , Carcinome canalaire du sein/anatomopathologie , Carcinome intracanalaire non infiltrant/imagerie diagnostique , Carcinome intracanalaire non infiltrant/anatomopathologie , Carcinome lobulaire/imagerie diagnostique , Carcinome lobulaire/anatomopathologie , Techniques d'aide à la décision , Dépistage précoce du cancer , Femelle , Humains , Modèles logistiques , Mammographie , Mastectomie/méthodes , Adulte d'âge moyen , Analyse multifactorielle , Grading des tumeurs , Réintervention/statistiques et données numériques , Facteurs de risque , Charge tumorale
5.
Br J Radiol ; 82(980): 640-4, 2009 Aug.
Article de Anglais | MEDLINE | ID: mdl-19332521

RÉSUMÉ

The purpose of this study was to assess the pattern and significance of tumour calcification in ovarian carcinoma. Patients with calcifying ovarian carcinoma were identified from radiological reports. Their tumour characteristics, serum calcium levels, treatment and survival were compared with a control group of patients with non-calcifying disease. Patterns and distribution of calcification were assessed. Available serial CT scans were reviewed for changes in both soft-tissue and calcified disease according to RECIST (response evaluation criteria in solid tumours) criteria where feasible. Temporal changes in calcification were correlated with changes in soft tissue disease and CA125 levels. The calcified group numbered 122 (22 other patients had calcifying tumour but insufficient clinical data). Calcification in ovarian carcinoma had a prevalence of 8% (144/1721) in our series. There was a significant difference (p<0.001) between the two groups in the distribution of histological type, with serous tumours being more common in the calcified group (74/122 (61%)) than in the controls (509/1498 (34%)). The calcified tumour patients tended to have lower grade disease (p<0.001). No differences between the groups were found for age, treatment or serum calcium levels. Distribution of calcification was diffusely peritoneal in 34 patients, in association with a pelvic mass in 15, nodal in 11 and within the anterior abdominal wall in 2. There was no correlation between changes in calcification on serial CT scans and corresponding CA125 levels. In conclusion, calcification tends to occur most commonly in serous cystadenocarcinomata and in tumours of lower grade. Changes in calcification cannot be used as a marker of disease response.


Sujet(s)
Calcinose , Tumeurs de l'ovaire , Adolescent , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Antigènes CA-125/sang , Calcinose/imagerie diagnostique , Calcinose/anatomopathologie , Calcium/sang , Études cas-témoins , Enfant , Angleterre , Femelle , Humains , Adulte d'âge moyen , Stadification tumorale , Tumeurs de l'ovaire/imagerie diagnostique , Tumeurs de l'ovaire/anatomopathologie , Études rétrospectives , Tomodensitométrie , Résultat thérapeutique , Jeune adulte
6.
Br J Radiol ; 82(980): 632-9, 2009 Aug.
Article de Anglais | MEDLINE | ID: mdl-19221182

RÉSUMÉ

This study aims to compare the sensitivity of whole-body MRI with bone scintigraphy in the detection of bone metastases in patients with renal cancer. A prospective study was carried out in 47 patients with renal cancer (mean age 62 years, range 29-79 years). All patients had assessment of the skeleton with whole-body bone scintigraphy (with technetium-99m methylene diphosphonate) and whole-body MRI (coronal T(1) weighted and short tau inversion recovery sequences). The number and sites of bony metastases were assessed on each imaging investigation independently. Sites of extra-osseous metastasis on MRI were also noted. The imaging findings were correlated with other imaging modalities and follow-up. 15 patients (32%) had bone metastases at 34 different sites. Both scintigraphy and MRI were highly specific (94% and 97%, respectively), but the sensitivity of MRI (94%) was superior (p = 0.007) to that of scintigraphy (62%). MRI identified more metastases in the spine and appendicular skeleton, whereas scintigraphy showed more lesions in the skull/facial and thoracic bones. MRI identified extra-osseous metastases in 33 patients (70%), these were mainly lung and retroperitoneal in site. Whole-body MRI is a more sensitive method for detection of bone metastases in renal cancer than bone scintigraphy, and also allows the assessment of soft-tissue disease.


Sujet(s)
Tumeurs osseuses/diagnostic , Tumeurs osseuses/secondaire , Néphrocarcinome/diagnostic , Néphrocarcinome/secondaire , Tumeurs du rein , Imagerie du corps entier/méthodes , Adulte , Sujet âgé , Tumeurs osseuses/imagerie diagnostique , Néphrocarcinome/imagerie diagnostique , Femelle , Humains , Imagerie par résonance magnétique/méthodes , Mâle , Adulte d'âge moyen , Études prospectives , Scintigraphie , Radiopharmaceutiques , Sensibilité et spécificité , Médronate de technétium (99mTc)
7.
Eur Radiol ; 18(5): 903-10, 2008 May.
Article de Anglais | MEDLINE | ID: mdl-18193234

RÉSUMÉ

To compare the diagnostic accuracy of MnDPDP MR imaging and diffusion-weighted imaging (DWI), alone and in combination, for detecting colorectal liver metastases in patients with suspected metastatic disease. Thirty-three consecutive patients with suspected colorectal liver metastases underwent MR imaging. Three image sets (MnDPDP, DWI and combined MnDPDP and DWI) were reviewed independently by two observers. Lesions were scored on a five-point scale for malignancy and the areas (Az) under the receiver operating characteristic curves were calculated for each observer and image set. The sensitivity and specificity for lesion detection were calculated for each image set and compared. There were 83 metastases, 49 cysts and 1 haemangioma. Using the combined set resulted in the highest diagnostic accuracy for both observers (Az=0.94 and 0.96), with improved averaged sensitivity of lesion detection compared with the DWI set (p=0.01), and a trend towards improved sensitivity compared with the MnDPDP set (p=0.06). There was no difference in the averaged specificity using any of the three image sets (p>0.5). Combination of MnDPDP MR imaging and DWI resulted in the highest diagnostic accuracy and can increase sensitivity without loss in specificity.


Sujet(s)
Tumeurs colorectales/anatomopathologie , Imagerie par résonance magnétique de diffusion , Tumeurs du foie/diagnostic , Imagerie par résonance magnétique/méthodes , Sujet âgé , Produits de contraste , Acide édétique/analogues et dérivés , Femelle , Humains , Tumeurs du foie/secondaire , Mâle , Adulte d'âge moyen , Biais de l'observateur , Études prospectives , Phosphate de pyridoxal/analogues et dérivés , Courbe ROC , Sensibilité et spécificité
8.
Br J Radiol ; 80(952): 242-7, 2007 Apr.
Article de Anglais | MEDLINE | ID: mdl-17005514

RÉSUMÉ

The purpose of this study was to assess the variability in the volume of the mesorectum in patients with rectal carcinoma. A retrospective review was made of pelvic MRI studies in 30 patients (mean age 64 years, range 34-88 years, 18M:12F) with histologically proven rectal carcinomas that were confined to the mesorectum. The outer low signal margin of the mesorectum was traced, over at least 10 consecutive 10 mm contiguous slices, until its disappearance. The visceral fascial compartment, body cross-sectional area and body mass index were measured, on a solitary slice, at the level of the L5/S1 disc. Linear regression was calculated for independent determinants of the mesorectal volume. Mean mesorectal volume in males was 227.5 cm3 (95%CI 191.6-263.4), and in females was 157.5 cm3 (95%CI 129.3-185.7). The difference in mesorectal volume between men and women was statistically significant (p<0.001). Mean visceral compartment area in males was 18.4 cm2 (95%CI 16.3-20.5) and in females was 14.6 cm2 (95%CI 12.8-16.4). Visceral compartment area correlated with mesorectal area and volume in females (p<0.05), and extremely well in males (p<0.005). Body cross-sectional area, body mass index and age did not correlate with mesorectal size. The correlation of visceral compartment area with mesorectal volume and mean area suggests that the mesorectum is determined in a similar way to other body fat compartments, with a similar anatomical variation. This significant variation in size and volume may have an important prognostic implication in patients with rectal carcinoma. This volume can be measured and reported on pre-operative MRI scanning and may be communicated to surgeons and radiotherapists.


Sujet(s)
Graisse abdominale/anatomopathologie , Tumeurs du rectum/anatomopathologie , Rectum/anatomopathologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Indice de masse corporelle , Fascia/anatomopathologie , Femelle , Humains , Imagerie par résonance magnétique/méthodes , Mâle , Adulte d'âge moyen , Soins préopératoires/méthodes , Pronostic , Tumeurs du rectum/chirurgie , Études rétrospectives , Facteurs sexuels
9.
Br J Radiol ; 80(957): 757-65, 2007 Sep.
Article de Anglais | MEDLINE | ID: mdl-16728414

RÉSUMÉ

Wegener's granulomatosis is an uncommon multisystemic disorder of unknown aetiology. It is characterized histopathologically by necrotizing granulomatous vasculitis. Most commonly this involves the upper and lower respiratory tract, with pulmonary involvement occurring at some stage of the disease in almost all patients. However, many other organ systems can also be affected including the kidneys, orbits and central nervous system. For this pictorial review, we have assessed the imaging of 155 patients over a 10-year period in order to illustrate characteristic and some of the more unusual imaging features of Wegener's granulomatosis.


Sujet(s)
Granulomatose avec polyangéite , Tomographie à rayons X , Adulte , Sujet âgé , Maladies osseuses/complications , Maladies osseuses/imagerie diagnostique , Maladies du système nerveux central/complications , Maladies du système nerveux central/imagerie diagnostique , Maladies des oreilles/complications , Maladies des oreilles/imagerie diagnostique , Femelle , Granulomatose avec polyangéite/complications , Granulomatose avec polyangéite/imagerie diagnostique , Cardiopathies/complications , Cardiopathies/imagerie diagnostique , Humains , Maladies du rein/complications , Maladies du rein/imagerie diagnostique , Imagerie par résonance magnétique , Mâle , Adulte d'âge moyen , Maladies du nez/complications , Maladies du nez/imagerie diagnostique , Maladies de l'orbite/complications , Maladies de l'orbite/imagerie diagnostique , Maladies de la rate/complications , Maladies de la rate/imagerie diagnostique
10.
Clin Radiol ; 61(4): 301-13, 2006 Apr.
Article de Anglais | MEDLINE | ID: mdl-16546459

RÉSUMÉ

Gestational trophoblastic neoplasia (GTN) encompasses a broad spectrum of placental lesions from the pre-malignant hydatidiform mole (complete and partial) through to the malignant invasive mole, choriocarcinoma and rare placental site trophoblastic tumour (PSTT). Ultrasound remains the radiological investigation of choice for initial diagnosis, and it can also predict invasive and recurrent disease. Magnetic resonance imaging is of invaluable use in assessing extra-uterine tumour spread, tumour vascularity, and overall staging. Positron emission tomography and computed tomography undoubtedly have a role in recurrent and metastatic disease, while angiography has a place in disease and complication management. This review will describe the relevant pathophysiology and natural history of GTN, and the use of imaging techniques in the diagnosis and management of these conditions.


Sujet(s)
Maladie trophoblastique gestationnelle/diagnostic , Femelle , Maladie trophoblastique gestationnelle/imagerie diagnostique , Maladie trophoblastique gestationnelle/secondaire , Humains , Soins de longue durée/méthodes , Imagerie par résonance magnétique , Tomographie par émission de positons , Grossesse , Tomodensitométrie , Échographie
11.
J Pept Res ; 65(6): 591-604, 2005 Jun.
Article de Anglais | MEDLINE | ID: mdl-15885118

RÉSUMÉ

Cognate interactions between immune effector cells and antigen-presenting cells (APCs) govern immune responses. Specific signals occur between the T-cell receptor peptide and APCs and nonspecific signals between pairs of costimulatory molecules. Costimulation signals are required for full T-cell activation and are assumed to regulate T-cell responses as well as other aspects of the immune system. As new discoveries are made, it is becoming clear how important these costimulation interactions are for immune responses. Costimulation requirements for T-cell regulation have been extensively studied as a way to control many autoimmune diseases and downregulate inflammatory reactions. The CD28:B7 and the CD40:CD40L families of molecules are considered to be critical costimulatory molecules and have been studied extensively. Blocking the interaction between these molecules results in a state of immune unresponsiveness termed 'anergy'. Several different strategies for blockade of these interactions are explored including monoclonal antibodies (mAbs), Fab fragments, chimeric, and/or fusion proteins. We developed novel, immune-specific approaches that interfere with these interactions. Using experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis mediated by central nervous system (CNS)-specific T-cells, we developed a multi-targeted approach that utilizes peptides for blockade of costimulatory molecules. We designed blocking peptide mimics that retain the functional binding area of the parent protein while reducing the overall size and are thus capable of blocking signal transduction. In this paper, we review the role of costimulatory molecules in autoimmune diseases, two of the most well-studied costimulatory pathways (CD28/CTLA-4:B7 and CD40:CD40L), and the advantages of peptidomimetic approaches. We present data showing the ability of peptide mimics of costimulatory molecules to suppress autoimmune disease and propose a mechanism for disease suppression.


Sujet(s)
Anticorps bloquants/usage thérapeutique , Maladies auto-immunes/thérapie , Biomimétique , Activation des lymphocytes/immunologie , Peptides/usage thérapeutique , Séquence d'acides aminés , Animaux , Maladies auto-immunes/immunologie , Humains , Données de séquences moléculaires , Lymphocytes T/immunologie
12.
Eur J Clin Microbiol Infect Dis ; 24(5): 319-24, 2005 May.
Article de Anglais | MEDLINE | ID: mdl-15891914

RÉSUMÉ

Clostridium clostridioforme shows much variability in phenotypic and antimicrobial susceptibility tests, suggesting it may be more than a single species even though all strains share unique morphology. This study was designed to determine if there are multiple species and, if so, to demonstrate the differences that exist between them. A total of 107 strains of C. clostridioforme were investigated by sequencing of the 16S rRNA gene, phenotypic studies, and antimicrobial susceptibility testing. In addition, clinical data from patients whose infections yielded an organism identified as C. clostridioforme was reviewed. Data from the above studies revealed three principal species in what has been called C. clostridioforme: Clostridium bolteae, C. clostridioforme, and Clostridium hathewayi. Each species may be distinguished by certain phenotypic tests. All three species were involved in infections, including bacteremia. C. clostridioforme appears to be associated with more serious or invasive human infections than the other two species in the group. Resistance to penicillin G is common and is due to beta-lactamase production. Resistance to clindamycin and moxifloxacin is also seen. The three species differ in terms of virulence and antimicrobial resistance. "C. clostridioforme" actually represents three distinct species that are different in terms of 16S rRNA sequences, phenotypic characteristics, and antimicrobial susceptibility. It is important for microbiology laboratories to distinguish between these species and for clinicians to be aware of the differences between them.


Sujet(s)
Antibactériens/pharmacologie , Clostridium/classification , Clostridium/effets des médicaments et des substances chimiques , Clostridium/génétique , Clostridium/pathogénicité , Infections à Clostridium/microbiologie , Résistance bactérienne aux médicaments , Humains , Phénotype , ARN ribosomique 16S/génétique
13.
Clin Radiol ; 58(11): 845-52, 2003 Nov.
Article de Anglais | MEDLINE | ID: mdl-14581007

RÉSUMÉ

Intra-articular osteoid osteoma accounts for approximately 13% of all osteoid osteomas and presents as a monoarthropathy. Radiographs commonly do not identify the nidus, and in this event, MRI is likely to be the next imaging investigation. MRI may show a variety of appearances depending upon the age of the lesion. This article illustrates the imaging features of intra-articular osteoid osteoma, with emphasis on MRI. CT remains the investigation of choice for identifying the nidus.


Sujet(s)
Tumeurs osseuses/diagnostic , Maladies articulaires/diagnostic , Ostéome ostéoïde/diagnostic , Adolescent , Adulte , Tumeurs osseuses/imagerie diagnostique , Enfant , Femelle , Humains , Maladies articulaires/imagerie diagnostique , Imagerie par résonance magnétique/méthodes , Mâle , Adulte d'âge moyen , Ostéome ostéoïde/imagerie diagnostique , Scintigraphie , Tomodensitométrie/méthodes
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 56A(12): 2423-30, 2000 Nov 01.
Article de Anglais | MEDLINE | ID: mdl-11075684

RÉSUMÉ

Infrared and Raman spectroscopies have been used to monitor the [2 + 2] photodimerisation reactions of alpha-trans-cinnamic acid and of a number of its derivatives. The principal changes observed in the spectra upon dimerisation are decay of a band around 1637 cm(-1), which is assigned to v(C=C) of the ethene bond of the monomer, and growth of bands just above 3000 cm(-1), which result from v(C-H) of saturated carbon atoms of the dimer. The use of microscope attachments has allowed us to follow the reactions of single crystals and we conclude that the reactions are topotactic in nature. We have carried out preliminary kinetic experiments in which spectra of one single crystal are recorded after sequential periods of photolysis. We find that the rates of dimerisation of differently substituted cinnamic acids are similar, with physical effects, such as the thickness of an individual crystal, outweighing any observed electronic effects (inductive or mesomeric).


Sujet(s)
Cinnamates/composition chimique , Photochimie/méthodes , Dimérisation , Microscopie/méthodes , Spectroscopie infrarouge à transformée de Fourier , Analyse spectrale Raman , Vibration
15.
J Clin Microbiol ; 38(1): 241-5, 2000 Jan.
Article de Anglais | MEDLINE | ID: mdl-10618094

RÉSUMÉ

The nucleotide sequences of internal transcribed spacer (ITS) regions of rRNA genes of 24 isolates of Histoplasma capsulatum were examined. The results indicate that the sequences of ITS regions in different isolates are not identical. Sequence variations were found at 20 positions in the 496 bp that were sequenced. Ten different sequence patterns, designated types A through H, were observed when the sequences from the 24 isolates were aligned. Twelve isolates from Indianapolis were classified into four different types. Two isolates from New York belonged to type G. Three isolates from different cities were type F. The remaining six isolates were of different types.


Sujet(s)
Gènes fongiques , Histoplasma/classification , ARN ribosomique/génétique , Syndrome d'immunodéficience acquise/complications , Syndrome d'immunodéficience acquise/microbiologie , Séquence nucléotidique , Clonage moléculaire , Histoplasma/génétique , Histoplasmose/complications , Histoplasmose/microbiologie , Humains , Données de séquences moléculaires , Réaction de polymérisation en chaîne , ARN ribosomique 5.8S/génétique , Analyse de séquence d'ADN
16.
Clin Infect Dis ; 30(1): 141-5, 2000 Jan.
Article de Anglais | MEDLINE | ID: mdl-10619742

RÉSUMÉ

Pneumocystis carinii pneumonia (PCP) is an important cause of morbidity and death among persons with human immunodeficiency virus (HIV) infection. Polymerase chain reaction (PCR) analysis of respiratory specimens has been investigated as a rapid diagnostic method. We have previously reported on the utility of this technique for diagnosing PCP in HIV-infected patients. In this report we evaluate PCR used in a blinded study design to avoid biases inherent to retrospective and nonblinded studies. The diagnosis of PCP was established on the basis of clinical findings and morphological studies of bronchoalveolar lavage (BAL) and/or lung biopsy specimens before PCR testing. PCR was performed without knowledge of the diagnosis. PCR results were graded from "negative" to 3+ on the basis of intensity of the banding pattern. Forty-seven patients were enrolled in the study, including 18 with proven PCP and 29 with other conditions. PCR was positive at grade 1 or higher for all 18 patients with PCP (100% sensitivity), at grade 2 or higher for 13 patients (72.2% sensitivity), and at grade 1 or higher for 4 of the 29 control patients (specificity of 86.2%). If a grade 2 or higher was required for diagnosis, the specificity improved to 100%. Results were reproducible with testing of a second aliquot for 46 of 47 patients (97.8%). Our findings confirm that PCR is a sensitive and reproducible test for detection of P. carinii in BAL specimens. Problems with false-positive results for control patients, however, limit the applicability of this method.


Sujet(s)
Infections opportunistes liées au SIDA/diagnostic , Pneumocystis/isolement et purification , Pneumonie à Pneumocystis/diagnostic , Réaction de polymérisation en chaîne/méthodes , Infections opportunistes liées au SIDA/microbiologie , Liquide de lavage bronchoalvéolaire/cytologie , Liquide de lavage bronchoalvéolaire/microbiologie , Études d'évaluation comme sujet , Humains , Poumon/microbiologie , Pneumocystis/génétique , Pneumonie à Pneumocystis/microbiologie , Études prospectives , Reproductibilité des résultats , Sensibilité et spécificité , Méthode en simple aveugle
17.
J Antibiot (Tokyo) ; 51(8): 743-9, 1998 Aug.
Article de Anglais | MEDLINE | ID: mdl-9766466

RÉSUMÉ

Syringomycin E (SR-E), a new antifungal produced by the bacterium Pseudomonas syringae pv. syringae, was evaluated in a murine vaginal candidiasis model. In one study, mice were treated intravaginally b.i.d. for 4 days with drug carrier, SR-E 2% in either PEG-400 or PEG-ointment, or 1% clotrimazole as a positive control. Quantitative vaginal cultures were taken prior to treatment on day 1 and on days 5, 6, and 7. Both formulations showed a reduction of yeast colonization in the vaginas on day 5 (P< or =0.06 and P< or =0.03 for SR-E/PEG-400 and SR-E/PEG ointment, respectively) and SR-E/PEG ointment reduced the colonization on day 7 (P< or =0.06) when compared to carrier treated controls. In a second study, SR-E was formulated in Aquaphor at three higher concentrations of SR-E [3%, 6%, or 12% (w/v)]. SR-E showed dose-dependent efficacy. The 3% dose showed no effect while the 6% and 12% doses reduced the number of yeasts. The 12% dose showed a significant reduction on days 5 (P< or =0.01), 6 (P< or =0.06), and 7 (P< or =0.03) when compared with the drug carrier controls and on day 5 was more effective than clotrimazole (P< or =0.03). Clotrimazole did not significantly reduce the yeasts in the vagina until days 6 (P< or =0.01) and 7 (P< or =0.01) when compared to the drug carrier controls. No vaginal inflammatory response was evident by histological examination in uninfected animals treated with SR-E. No SR-E could be detected in plasma, kidney, or liver. SR-E (12%) was an effective treatment when compared to 1% clotrimazole.


Sujet(s)
Antifongiques/usage thérapeutique , Candidose vulvovaginale/traitement médicamenteux , Peptides cycliques/usage thérapeutique , Animaux , Antifongiques/sang , Chromatographie en phase liquide à haute performance , Clotrimazole/usage thérapeutique , Modèles animaux de maladie humaine , Relation dose-effet des médicaments , Vecteurs de médicaments , Femelle , Foie/effets des médicaments et des substances chimiques , Souris , Souris de lignée ICR , Peptides cycliques/sang
18.
Diagn Microbiol Infect Dis ; 28(1): 27-9, 1997 May.
Article de Anglais | MEDLINE | ID: mdl-9218915

RÉSUMÉ

Collaborative studies documented the reproducibility of broth microdilution susceptibility tests of Streptococcus pneumoniae against nine antimicrobial agents and of disk diffusion tests with six of those drugs. Replicate tests of Streptococcus pneumoniae ATCC 49619 in five different laboratories led to the following provisional quality control limits: cefdinir--0.03 to 0.25 microgram/ml and 26 to 31 mm; cefetamet--0.5 to 2 micrograms/ml and 20 to 25 mm; ciprofloxacin--0.25 to 1 microgram/ml and 20 to 26 mm; clinafloxacin--0.03 to 0.125 microgram/ml and 28 to 34 mm; grepafloxacin--0.06 to 0.5 microgram/ml and 21 to 28 mm; PD131628--0.125 to 0.5 microgram/ml and 24 to 29 mm; clindamycin--0.03 to 0.12 microgram/ml; cefpodoxime--0.03 to 0.12 microgram/ml; and trospectomycin--1 to 4 microgram/ml (disk tests were not evaluate for the latter three drugs).


Sujet(s)
Antibactériens/pharmacologie , Tests de sensibilité microbienne , Streptococcus pneumoniae/effets des médicaments et des substances chimiques , Tests de sensibilité microbienne/méthodes , Tests de sensibilité microbienne/normes , Reproductibilité des résultats
19.
Appl Opt ; 36(10): 2217-21, 1997 Apr 01.
Article de Anglais | MEDLINE | ID: mdl-18253196

RÉSUMÉ

We have developed a simple, noncontact, fiber-optic proximity sensor, using a laser micromachined tap on a single multimode optical fiber. The fiber end is placed near a target surface, and a beam of light is incident from the fiber onto the target. Some fraction of this light is reflected or scattered by the target and coupled back into the fiber. The amount recoupled into the fiber is dependent on the distance between the fiber end and the target surface as well as on other parameters such as the target's surface roughness. The fiber-optic tap allows us to monitor both the initial amount of light launched down the fiber toward the target and the amount of backreflected light from the target. For a known environment and target surface, variations in source intensity can be compensated for by monitoring the ratio of the two counterpropagating beams.

20.
J Clin Microbiol ; 35(1): 281-3, 1997 Jan.
Article de Anglais | MEDLINE | ID: mdl-8968926

RÉSUMÉ

We have developed a novel method for the preparation of fecal specimens for PCR assays. Approximately 100 mg of solid stool or 200 microliters of liquid fecal sample was thoroughly suspended in 1 ml of water. Fecal debris was removed by low-speed centrifugation (2,800 x g for 2 min). The supernatant was then boiled for 10 min in a water bath and further clarified by high-speed centrifugation (12,000 x g for 5 min). Fifty microliters of the clarified supernatant was then purified by Sepharose CL-6B spin column chromatography, and a portion of the purified supernatant was used for PCR. By this method, stools containing enterotoxigenic Escherichia coli H10407 were amplified by colonization factor antigen I fimbrial gene PCR, with a sensitivity of 100 organisms per reaction. The method was also effective for processing stool specimens for Clostridium difficile toxin A and B gene PCRs. This method is rapid, effective, and simple to perform and will improve the applications of PCR to stool specimens for diagnostic purposes.


Sujet(s)
Techniques de typage bactérien , Fèces/microbiologie , Réaction de polymérisation en chaîne/méthodes
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