Resistance of disposable drapes to bacterial penetration

PURPOSE

To test the bacterial penetrability of disposable non-woven drapes used specifically for total hip arthroplasty.

METHODS

12 round agar plates were inoculated with 107 colony-forming units/ml of coagulase-negative staphylococci (CNS) and incubated in air at 37 degrees Celsius for 18 hours to obtain a semi-confluent growth of organisms. Six brands of disposable drapes were tested; each was assigned to 2 plates. Each disposable drape was placed between a round agar plate and an inverted square agar plate filled with blood agar. After 30 and 90 minutes, the square agar plates were removed and incubated for 48 hours and inspected for growth of CNS.

RESULTS

Bacterial penetration was time dependant. Certain brands of drapes were more impenetrable than others; none was impenetrable at all time points, but most remained so or allowed passage of fewer than 100 colony-forming units at 90 minutes.

CONCLUSION

It is recommended that drapes be rigorously tested with regard to their resistance to bacterial penetration.

[Digital mammography: performance evaluation parameters and available systems in France]

The purpose of this article is to review the features of digital mammography systems available in France. This article includes three parts: definition of the different components of a digital mammography system, description of different performance evaluation parameters, and review of systems currently available in France. Data from the literature as well as questionnaires from different manufacturers were used. The following vendors agreed to participate: Agfa, Fujifilm, GE Healthcare, Hologic-Lorad, IMS, Kodak, Konica Minolta, Philips, Planmed, Sectra, Siemens. For each vendor, the type of detector, type of available mammographic units and workstation, optional features (CAD), archival and printing possibilities (when vendors specifically offer dedicated solutions).

Equivalent uniform dose concept evaluated by theoretical dose volume histograms for thoracic irradiation

BACKGROUND AND PURPOSE

The goal of our study was to quantify the limits of the EUD models for use in score functions in inverse planning software, and for clinical application.

MATERIALS AND METHODS

We focused on oesophagus cancer irradiation. Our evaluation was based on theoretical dose volume histograms (DVH), and we analyzed them using volumetric and linear quadratic EUD models, average and maximum dose concepts, the linear quadratic model and the differential area between each DVH.

RESULTS

We evaluated our models using theoretical and more complex DVHs for the above regions of interest. We studied three types of DVH for the target volume: the first followed the ICRU dose homogeneity recommendations; the second was built out of the first requirements and the same average dose was built in for all cases; the third was truncated by a small dose hole. We also built theoretical DVHs for the organs at risk, in order to evaluate the limits of, and the ways to use both EUD(1) and EUD/LQ models, comparing them to the traditional ways of scoring a treatment plan. For each volume of interest we built theoretical treatment plans with differences in the fractionation.

CONCLUSION

We concluded that both volumetric and linear quadratic EUDs should be used. Volumetric EUD(1) takes into account neither hot-cold spot compensation nor the differences in fractionation, but it is more sensitive to the increase of the irradiated volume. With linear quadratic EUD/LQ, a volumetric analysis of fractionation variation effort can be performed.

Guidelines on the standards for the training of specialised health professionals dealing with breast cancer

According to EUSOMA position paper 'The requirements of a specialist breast unit', each breast unit should have a core team made up of health professionals who have undergone specialist training in breast cancer. In this paper, on behalf of EUSOMA, authors have identified the standards of training in breast cancer, to harmonise and foster breast care training in Europe. The aim of this paper is to contribute to the increase in the level of care in a breast unit, as the input of qualified health professionals increases the quality of breast cancer patient care.

Expression of a disintegrin and metalloprotease (ADAM and ADAMTS) enzymes in human non-small-cell lung carcinomas (NSCLC)

A Disintegrin and Metalloprotease (ADAM) are transmembrane proteases displaying multiple functions. ADAM with ThromboSpondin-like motifs (ADAMTS) are secreted proteases characterised by thrombospondin (TS) motifs in their C-terminal domain. The aim of this work was to evaluate the expression pattern of ADAMs and ADAMTS in non small cell lung carcinomas (NSCLC) and to investigate the possible correlation between their expression and cancer progression. Reverse transcriptase–polymerase chain reaction (RT–PCR), Western blot and immunohistochemical analyses were performed on NSCLC samples and corresponding nondiseased tissue fragments. Among the ADAMs evaluated (ADAM-8, -9, -10, -12, -15, -17, ADAMTS-1, TS-2 and TS-12), a modulation of ADAM-12 and ADAMTS-1 mRNA expression was observed. Amounts of ADAM-12 mRNA transcripts were increased in tumour tissues as compared to the corresponding controls. In sharp contrast, ADAMTS-1 mRNA levels were significantly lower in tumour tissues when compared to corresponding nondiseased lung. These results were corroborated at the protein level by Western blot and immunohistochemistry. A positive correlation was observed between the mRNA levels of ADAM-12 and those of two vascular endothelial growth factor (VEGF)-A isoforms (VEGF-A₁₆₅ and VEGF-A₁₂₁). Taken together, these results providing evidence for an overexpression of ADAM-12 and a lower expression of ADAMTS-1 in non-small-cell lung cancer suggest that these proteases play different functions in cancer progression.

Development of educational image databases and e-books for medical physics training

Medical physics education and training requires the use of extensive imaging material and specific explanations. These requirements provide an excellent background for application of e-Learning. The EU projects Consortia EMERALD and EMIT developed five volumes of such materials, now used in 65 countries. EMERALD developed e-Learning materials in three areas of medical physics (X-ray diagnostic radiology, nuclear medicine and radiotherapy). EMIT developed e-Learning materials in two further areas: ultrasound and magnetic resonance imaging. This paper describes the development of these e-Learning materials (consisting of e-books and educational image databases). The e-books include tasks helping studying of various equipment and methods. The text of these PDF e-books is hyperlinked with respective images. The e-books are used through the readers' own Internet browser. Each Image Database (IDB) includes a browser, which displays hundreds of images of equipment, block diagrams and graphs, image quality examples, artefacts, etc. Both the e-books and IDB are engraved on five separate CD-ROMs. Demo of these materials can be taken from www.emerald2.net.

Smooth muscle cell matrix metalloproteinases in idiopathic pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) results from persistent vasoconstriction, smooth muscle growth and extracellular matrix (ECM) remodelling of pulmonary arteries (PAs). Matrix metalloproteinases (MMPs) are matrix-degrading enzymes involved in ECM turnover, and in smooth muscle cell (SMC) and endothelial cell migration and proliferation. MMP expression and activity are increased in experimental PAH. Therefore, this study investigated whether similar changes occur in idiopathic PAH (IPAH; formerly known as primary pulmonary hypertension). Both in situ and in vitro studies were performed on PAs from patients undergoing lung transplantation for IPAH and from patients treated by lobectomy for localised lung cancer, who served as controls. In IPAH, MMP-tissue inhibitor of metalloproteinase (TIMP) imbalance was found in cultured PA-SMCs, with increased TIMP-1 and decreased MMP-3. MMP-2 activity was markedly elevated as a result of increases in both total MMP-2 and proportion of active MMP-2. In situ zymography and immunolocalisation showed that MMP-2 was associated with SMCs and elastic fibres, and also confirmed the MMP-3-TIMP-1 imbalance. In conclusion, the findings of this study were consistent with a role for the matrix metalloproteinase-tissue inhibitor of metalloproteinase system in pulmonary vascular remodelling in idiopathic pulmonary arterial hypertension. The matrix metalloproteinase-tissue inhibitor of metalloproteinase imbalance may lead to matrix accumulation, and increased matrix metalloproteinase-2 activity may contribute to smooth muscle cell migration and proliferation. Whether these abnormalities are potential therapeutic targets deserves further investigation.

Membrane type-matrix metalloproteinases and tumor progression

Matrix metalloproteinases (MMPs) are a family of zinc endopeptidases that process growth factors, growth factor binding proteins, cell surface proteins, degrade extracellular matrix (ECM) components and thereby play a central role in tissue remodeling and tumor progression. Membrane-type matrix metalloproteinases (MT-MMPs) are a recently discovered subgroup of intrinsic plasma membrane proteins. Their functions have been extended from pericellular proteolysis and control of cell migration to cell signaling, control of cell proliferation and regulation of multiple stages of tumor progression including growth and angiogenesis. This review sheds light on the new functions of MT-MMPs and their inhibitors in tumor development and angiogenesis, and presents recent investigations that document their influence on various cell functions.

Digital detectors for mammography: the technical challenges

This paper reviews the different techniques available and competing for full-field digital mammography. The detectors are described in their principles: photostimulable storage phosphor plates inserted as a cassette in a conventional mammography unit, dedicated active matrix detectors (i.e., flat-panel, thin-film transistor-based detectors) and scanning systems, using indirect and direct X-ray conversion. The main parameters that characterize the performances of the current systems and influence the quality of digital images are briefly explained: spatial resolution, detective quantum efficiency and modulation transfer function. Overall performances are often the result of compromises in the choice of technology.

Influence of detector collimation on SNR in four different MDCT scanners using a reconstructed slice thickness of 5�mm

The purpose of this paper is to compare the influence of detector collimation on the signal-to-noise ratio (SNR) for a 5.0 mm reconstructed slice thickness for four multi-detector row CT (MDCT) units. SNRs were measured on Catphan test phantom images from four MDCT units: a GE LightSpeed QX/I, a Marconi MX 8000, a Toshiba Aquilion and a Siemens Volume Zoom. Five-millimetre-thick reconstructed slices were obtained from acquisitions performed using detector collimations of 2.0-2.5 mm and 5.0 mm, 120 kV, a 360 degrees tube rotation time of 0.5 s, a wide range of mA and pitch values in the range of 0.75-0.85 and 1.25-1.5. For each set of acquisition parameters, a Wiener spectrum was also calculated. Statistical differences in SNR for the different acquisition parameters were evaluated using a Student's t-test (P<0.05). The influence of detector collimation on the SNR for a 5.0-mm reconstructed slice thickness is different for different MDCT scanners. At pitch values lower than unity, the use of a small detector collimation to produce 5.0-mm thick slices is beneficial for one unit and detrimental for another. At pitch values higher than unity, using a small detector collimation is beneficial for two units. One manufacturer uses different reconstruction filters when switching from a 2.5- to a 5.0-mm detector collimation. For a comparable reconstructed slice thickness, using a smaller detector collimation does not always reduce image noise. Thus, the impact of the detector collimation on image noise should be determined by standard deviation calculations, and also by assessing the power spectra of the noise.

Membrane associated proteases and their inhibitors in tumour angiogenesis

Cell surface proteolysis is an important mechanism for generating biologically active proteins that mediate a range of cellular functions and contribute to biological processes such as angiogenesis. Although most studies have focused on the plasminogen system and matrix metalloproteinases (MMPs), recently there has been an increase in the identification of membrane associated proteases, including serine proteases, ADAMs, and membrane-type MMPs (MT-MMPs). Normally, protease activity is tightly controlled by tissue inhibitors of MMPs (TIMPs) and plasminogen activator inhibitors (PAIs). The balance between active proteases and inhibitors is thought to determine the occurrence of proteolysis in vivo. High concentrations of proteolytic system components correlate with poor prognosis in many cancers. Paradoxically, high (not low) PAI-1 or TIMP concentrations predict poor survival in patients with various cancers. Recent observations indicate a much more complex role for protease inhibitors in tumour progression and angiogenesis than initially expected. As knowledge in the field of protease biology has improved, the unforeseen complexities of cell associated enzymes and their interaction with physiological inhibitors have emerged, often revealing unexpected mechanisms of action.

Radiothérapie conformationnelle avec modulation d'intensité des cancers des voies aérodigestives supérieures avec irradiation bilatérale du cou : résultats préliminaires

PURPOSE

To report preliminary results of a prospective study of intensity-modulated radiotherapy (IMRT) for head and neck squamous cell carcinoma (HNC) with bilateral irradiation of the neck.

PATIENTS AND METHODS

At the Alexis Vautrin Cancer Center, 23 patients have been treated with IMRT for HNC since January 2002-August 2003. The first 10 patients with a minimum follow-up of 3 months were analyzed. All tumors were oropharyngeal. There were four females and six males, with a mean age of 50 years (range 39-66). Stages were I-II in eight and III-IV in two. CTV1 was microscopic disease and N0 neck (prescribed dose : 50 Gy) and CTV2 was macroscopic disease and the volume at risk (prescribed dose: 66-70 Gy). PTV were CTV + 5 mm. Patient's immobilization consisted of a five-point head neck shoulder thermoplastic mask. Set-up verifications were done by semi-automatically matching portal images and digitized reconstructed radiographs. IMRT used dynamic multileaf collimation. Five patients (group A) received 50 Gy IMRT (two post-operative and three with a brachytherapy boost with a mean dose: 27.5 Gy), and five patients (group B) received 66-70 Gy IMRT (four post-operative). Acute and late normal tissue effects were graded according to the RTOG-EORTC radiation morbidity scoring criteria.

RESULTS

With a median follow-up of 7.4 months (range 3-18.5), no patient died or had loco-regional relapse. The displacements were <4 mm in 98% cases. CTV1 and 2 received 95% of the prescribed dose in 100% of the volume. On average the mean dose to the contralateral parotid was 25.5 Gy for group A vs. 31 Gy for group B (P = 0.09). Mean doses <26 Gy were obtained in three of five patients in group A vs. zero of five patients in group B (P = 0.04). Acute skin toxicities were grade 1 in five patients, grade 2 in four and grade 3 in one. Acute mucositis cases were grade 1 in three patients, grade 2 in five and localized grade 3 in two. At 3 months, 50% of the patients had a grade 0-1 late xerostomia.

CONCLUSION

The 26 Gy dose limit constraint to the contralateral parotid was easier to satisfy when IMRT was prescribed at a maximum dose of 50 Gy. Acute toxicity is low. The displacements in the mask indicate that it is possible to define the PTV as CTV + 4 mm. This reduction should decrease the mean dose to the parotids. At 3 months, a 50% rate of grade 0-1 late xerostomia encourages the hope of a very low rate at 2 years.

Crystal structure of the catalytic domain of MMP-16/MT3-MMP: characterization of MT-MMP specific features

Membrane-type matrix metalloproteinases (MT-MMPs) have attracted strong attention, because four of them can activate a key player in the tumor scenario, proMMP-2/progelatinase A. In addition to this indirect effect on the cellular environment, these MT-MMPs degrade extracellular matrix proteins, and their overproduction is associated with tumor growth. We have solved the structure of the catalytic domain (cd) of MT3-MMP/MMP-16 in complex with the hydroxamic acid inhibitor batimastat. CdMT3-MMP exhibits a classical MMP-fold with similarity to MT1-MMP. Nevertheless, it also shows unique properties such as a modified MT-specific loop and a closed S1' specificity pocket, which might help to design specific inhibitors. Some MT-MMP-specific features, derived from the crystal structures of MT-1-MMP determined previously and MT3-MMP, and revealed in recent mutagenesis experiments, explain the impaired interaction of the MT-MMPs with TIMP-1. Docking experiments with proMMP-2 show some exposed loops including the MT-loop of cdMT3-MMP involved in the interaction with the proMMP-2 prodomain in the activation encounter complex. This model might help to understand the experimentally proven importance of the MT-loop for the activation of proMMP-2.

Pathogenic role of matrix metalloproteases and their inhibitors in asthma and chronic obstructive pulmonary disease and therapeutic relevance of matrix metalloproteases inhibitors

Matrix metalloproteinases (MMPs) are an at least 23 member family of calcium and zinc dependent enzymes implicated in many physiological and pathological processes. Asthma, chronic obstructive pulmonary disease (COPD) and emphysema are diseases associated with an inflammation of the airways and lung parenchyma. In this review, we focus on the role played by MMPs in the pathogenesis of inflammation, airway remodelling and alveolar destruction, depicting the observational studies in humans and the experimental studies in animal models. During the course of asthma, MMP-2,-8,-9 and TIMP-1 are expressed at baseline and the allergen exposure or exacerbations of the disease lead to an increase of MMP-9 secretion being at this time much higher than that of TIMP-1, allowing temporarily a matrix damage, possibly followed by abnormal repair. Animal models suggest a predominant role for MMP-9 and MMP-12 in the pathogenesis of pulmonary inflammation and link an absence of MMP-2 to an increased parenchymal inflammation. In COPD and emphysema, human studies indicate an over-secretion of MMP-2,-8,-9 and animal models pointout MMP-1 and MMP-12 as being key players in the pathogenesis of emphysema. Taken together, these data identify specific MMP inhibition as appropriate target for therapeutic intervention in asthma or COPD/emphysema They also strongly argue against the widespread use of large spectrum non specific inhibitors that could be detrimental.