Study of nitrogen implantation in Ti surface using plasma immersion ion implantation & deposition technique as biocompatible substrate for artificial membranes.

The present investigation reports the modification of Ti substrates by a plasma technique to enhance their physio-chemical properties as biocompatible substrates for the deposition of artificial membranes. For that purpose, nitrogen ions are implanted into Ti substrate using the plasma immersion ion implantation & deposition (PIII&D) technique in a capacitively coupled radio frequency plasma. The plasma was characterized using optical emission spectroscopy, together with radio frequency compensated Langmuir probe, while the ion current towards the substrate was measured during the implantation process using an opto-electronic device. X-ray photoelectron spectroscopy (XPS) was used for chemical analysis of the surface, confirming the presence of δ-TiN. The penetration depth of the nitrogen ions into the Ti substrate was measured using secondary ions mass spectroscopy (SIMS) while the morphological changes were observed using atomic force microscopy (AFM). A calorimetric assay was used to prove that the TiN samples maintain the biocompatibility of the untreated Ti surface with its native oxide layer. The ion implantation increases the load bearing ability of Ti surface by the formation of α-Ti(N) and δ-TiN phases on the sub-surface of Ti, and maintains the bio compatibility of Ti surface. After the plasma treatment a thin layer of chitosan (CH) was deposited in order to provide a moisturizing matrix for the artificial membrane of 1,2-dipalmitoyl-sn-3- phosphor glycerocholine (DPPC). The CH and subsequently the DPPC were deposited on the plasma deposited TiN substrate by using physical vapor deposition. The formation of artificial membranes was confirmed by AFM, measuring the topography at different temperatures and performing force curves.

[HPV contamination of endocavity vaginal ultrasound probes]. / Contamination des sondes d'échographie endovaginale par les papillomavirus humains.

While the use of endovaginal ultrasound probes is increasing, the risk of contamination of women with endocavity vaginal probes was not assessed. In particular, the clinical significance of detection of human papillomavirus (HPV) infection, the most common sexually transmitted viral infection, on endovaginal ultrasound probes is uncertain. The recommendations of good practice for decontamination of these probes developed by the High Council for Public Health and the Academy of Medicine have not been evaluated. The objective of this article was to review recent publications concluding to the detection of HPV and human cellular DNA after gynecological examination and disinfection of vaginal ultrasound probes.

Cleaning of conveyor belt materials using ultrasound in a thin layer of water.

Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.

Prospective study of cutaneous side-effects associated with the BRAF inhibitor vemurafenib: a study of 42 patients.

BACKGROUND: BRAF inhibitors are being developed for the treatment of metastatic melanoma harboring a V600E mutation. The use of vemurafenib significantly increases progression-free survival (PFS) and overall survival (OS) in this population of patients, but is associated with numerous adverse skin reactions. PATIENTS AND METHODS: We carried out a systematic dermatologic study of 42 patients treated with vemurafenib. We collected detailed dermatologic symptoms, photos and biopsy specimens of the skin lesions which enabled us to classify the side-effects. The management and evolution of the skin symptoms are also reported. RESULTS: All patients presented with at least one adverse skin reaction. The most common cutaneous side-effects consisted in verrucous papillomas (79%) and hand-foot skin reaction (60%). Other common cutaneous toxic effects were a diffuse hyperkeratotic perifollicular rash (55%), photosensitivity (52%) and alopecia (45%). Epidermoid cysts (33%) and eruptive nevi (10%) were also observed. Keratoacanthomas (KA) and squamous cell carcinoma (SCC) occurred in 14% and 26% of the patients, respectively. CONCLUSIONS: These cutaneous side-effects are cause of concern due to their intrinsic potential for malignancy or because of their impact on patients' quality of life. Management of this skin toxicity relies on symptomatic measures and sun photoprotection.

EVER2 protein binds TRADD to promote TNF-α-induced apoptosis.

EVER1 and 2 confer resistance to cutaneous oncogenic human papillomavirus infections by downregulating the activating protein 1 (AP-1) signaling pathway. Defects in their expression are associated with susceptibility to epidermodysplasia verruciformis, which is characterized by persistent ß-HPV infection, tumor necrosis factor alpha (TNF-α) overproduction in keratinocytes and the development of skin cancers. TNF-α-induced apoptosis is a key defense strategy, preventing the persistence of the virus within cells, but the role of EVER proteins in this cell death mechanism triggered by extrinsic stimuli is unknown. We show here that EVER2 induces TNF-α- and TRAIL-dependant apoptosis. It interacts with the N-terminal domain of TRADD, impairs the recruitment of TRAF2 and RIPK1 and promotes apoptosis. The skin cancer-associated EVER2 I306 allele results in an impaired TRADD-EVER2 interaction, with lower levels of cell death following treatment with TNF-α. These data highlight a new, critical function of EVER2 in controlling cell survival in response to death stimuli.

Force spectroscopy of barnase-barstar single molecule interaction.

Results of the single molecule force spectroscopy study of specific interactions between ribonuclease barnase and its inhibitor barstar are presented. Experimental data obtained for the force loading rate ranging 2-70 nN/s are well approximated by a single straight line, from which the dissociation barrier of the width of 0.12 nm and height of 0.75-0.85 × 10(-19)J can be inferred. The measured value of specific interaction does not depend on the NaCl concentration. This apparently contradicts the well-known dependence of the binding energy of this pair on the salt concentration, but such a "contradiction" is explained by the insensitivity of the force spectroscopy data to the relatively long-range electrostatic interaction. The latter essentially contributes to the value of barnase-barstar binding energy revealed by biochemical measurements, and it is exactly this electrostatic interaction which is influenced by the salt concentration.

Fast plasma discharge capillary design as a high power throughput soft x-ray emission source.

We present the experimental details and results from a low energy but high repetition rate compact plasma capillary source for extreme ultraviolet and soft x-ray research and applications. Two lengths of capillary are mounted in two versions of a closely related design. The discharge operates in 1.6 and 3.2 mm inner diameter alumina capillaries of lengths 21 and 36 mm. The use of water both as dielectric and as coolant simplifies the compact low inductance design with nanosecond discharge periods. The stored electrical energy of the discharge is approximately 0.5 J and is provided by directly charging the capacitor plates from an inexpensive insulated-gate bipolar transistor in 1 µs or less. We present characteristic argon spectra from plasma between 30 and 300 Å as well as temporally resolved x-ray energy fluence in discrete bands on axis. The spectra also allow the level of ablated wall material to be gauged and associated with useful capillary lifetime according to the chosen configuration and energy storage. The connection between the electron beams associated with the transient hollow cathode mechanism, soft x-ray output, capillary geometry, and capillary lifetime is reported. The role of these e-beams and the plasma as measured on-axis is discussed. The relation of the electron temperature and the ionization stages observed is discussed in the context of some model results of ionization in a non-Maxwellian plasma.

ViralORFeome: an integrated database to generate a versatile collection of viral ORFs.

Large collections of protein-encoding open reading frames (ORFs) established in a versatile recombination-based cloning system have been instrumental to study protein functions in high-throughput assays. Such 'ORFeome' resources have been developed for several organisms but in virology, plasmid collections covering a significant fraction of the virosphere are still needed. In this perspective, we present ViralORFeome 1.0 (http://www.viralorfeome.com), an open-access database and management system that provides an integrated set of bioinformatic tools to clone viral ORFs in the Gateway(R) system. ViralORFeome provides a convenient interface to navigate through virus genome sequences, to design ORF-specific cloning primers, to validate the sequence of generated constructs and to browse established collections of virus ORFs. Most importantly, ViralORFeome has been designed to manage all possible variants or mutants of a given ORF so that the cloning procedure can be applied to any emerging virus strain. A subset of plasmid constructs generated with ViralORFeome platform has been tested with success for heterologous protein expression in different expression systems at proteome scale. ViralORFeome should provide our community with a framework to establish a large collection of virus ORF clones, an instrumental resource to determine functions, activities and binding partners of viral proteins.

Force-clamp spectroscopy with a small dithering of AFM tip, and its application to explore the energy landscape of single avidin-biotin complex.

We have recently developed a new method for directly measuring the spring constant of single molecules and molecular complexes on a real-time basis [L.A. Chtcheglova, G.T. Shubeita, S.K. Sekatskii, G. Dietler, Biophys. J. 86 (2004) 1177]. The technique combines standard force spectroscopy with a small dithering of tip. Changes in the amplitude of the oscillations are measured as a function of the pulling-off force to yield the spring constant of the complex. In this report, we present the first results of combination of this approach with the force-clamp spectroscopy. The standard atomic-force microscope has been supplemented with an electronic unit, which is capable of realizing an arbitrary force function, and permits the force-loading regime to be interrupted at any time. Using this method, the time needed to rupture a single bond can be measured as a function of the force that is required to maintain the complex in a stretched condition. The energy landscape of the avidin-biotin complex is explored and discussed.

Interactive measurement and characterization of DNA molecules by analysis of AFM images.

BACKGROUND: In the past few years, computer-based analysis of atomic-force microscopic images has acquired increasing importance for studying biomolecules such as DNA. On the one hand, fully automated methods do not allow analysis of complex shapes; on the other hand, manual methods are usually time consuming and inaccurate. The semiautomated approach presented in this report overcomes the drawbacks of both methods. METHODS: Two kinds of images were analyzed: computer-generated filaments that modeled circular DNA molecules on a surface and real atomic-force microscopic images of DNA molecules adsorbed on an appropriate substrate surface. RESULTS: The algorithm was tested on a group of 140 simulated and 189 real plasmids with a nominal length of 913 nm. The accuracy of the length measurement was statistically evaluated on the ensemble of molecules, with particular attention to the influence of the noise. Mean contour lengths of 912 +/- 5 nm and 910 +/- 47 nm were found for simulated and real plasmids, respectively. The measured end-to-end distance of lambda-DNA molecules as a function of their contour length is reported, from which it is possible to estimate the stiffness of the DNA molecules adsorbed onto a surface; the value obtained for the DNA persistence length (42 +/- 5 nm) is consistent with values measured by other imaging techniques. CONCLUSIONS: An interactive algorithm for DNA molecule measurements based on the detection of the filament ridge line in a digitized image is presented. The simulation of artificial filaments combined with the experimental data demonstrates that the proposed method can be a valuable tool for the DNA contour length evaluation, especially in the case of complex shapes where the use of automatic methods is not possible.

High frequency of detection of human papillomaviruses associated with epidermodysplasia verruciformis in children with psoriasis.

BACKGROUND: Psoriasis is a T-cell-mediated immunological disease characterized by epidermal proliferation. The nature of the antigen(s) responsible for T-cell activation is still unknown. It has been suggested that the human papillomaviruses (HPVs) associated with epidermodysplasia verruciformis (EV), including the oncogenic HPV5, may contribute to the pathogenesis of psoriasis. OBJECTIVES: To determine whether EV-HPVs may play a role early in the disease, we searched for these viruses in children with psoriasis. The influence of clinical data on EV-HPV infection was investigated. METHODS: We studied scrapings of involved skin from 26 children aged 1.5-13 years with psoriasis. As controls, we analysed scrapings from 28 adults with psoriasis and 15 children with atopic dermatitis, as well as scrapings from normal skin of 28 adults with no known history of HPV infection. We searched for EV-HPV DNA sequences with a nested polymerase chain reaction method using degenerate primers specific for EV-HPVs and primers specific for HPV5 and HPV36, two EV-HPVs frequently detected in adults with psoriasis. RESULTS: Similar high prevalences were observed in children and adults with psoriasis for EV-HPVs (38.5% vs. 35.7%), HPV5 (46.2% vs. 46.4%) and HPV36 (15.4% vs. 25.0%). As in adults, we found several EV-HPV genotypes and HPV5 and HPV36 variants. A novel HPV36 subtype, HPV36b, was identified. Lower prevalences were observed in children with atopic dermatitis and in adults from the general population (6.7-10.1%). No correlation was observed between frequency of detection of HPVs and clinical data. It is noteworthy that HPV5 was identified in an 18-month-old girl and in a boy with psoriasis developing for only 1 week. CONCLUSIONS: The early detection of several EV-HPV genotypes in children further supports the link between psoriasis and EV-HPVs and suggests a putative role for these viruses in the pathogenesis of psoriasis.

Lithium dose prediction based on 24 hours single dose levels: a prospective evaluation.

The authors present the results of the utilization of a pharmacokinetic prediction test for lithium posology. Based on a single point (plasma lithium determination 24 h after a single dose) such a test aims to adapt the posology as soon as the second day of treatment rather than after one week as clinicians must wait for a steady state to be achieved. Built on the previous work of Perry, the test targeted the plasma lithium level at 0.8 +/- 0.1 mmol l(-1). Thirty-one patients took part in the study. There were two drop-out cases and the results were available for 29 patients: among them, 51% had their plasma level in the targeted zone. Although there was no control group, the prediction test often allowed us to use a higher dose than the usual fixed dose whose amount is limited by the risk of overdosing for the slower metabolizers.

[Exercise test and evaluation of exertional dyspnoea in former coal miners]. / Test d'exercice et évaluation de la dyspnée d'effort des anciens mineurs de charbon.

The decrease in pulmonary function tests (PFTs) in retired coal miners who complain of increased exercise dyspnoea does not precisely reflect exercise tolerance. PFTs and a maximal cardiopulmonary exercise test in order to determine peak were performed in thirty-eight patients (69.7 +/- 6.7 years old). They also completed a six-minute walk test (6MWD) in order to evaluate its sensibility to detect a limitation of peak. Quality of life was assessed by the Saint George's Hospital Respiratory Questionnaire (SGRQ). PFTs were within normal values in 21 patients whereas 8 patients showed an obstructive pattern, 4 a restrictive one and 5 gas exchange abnormalities only. We found a mild decrease in peak at 70.4 +/- 15.9% of reference value. Exercise limitation was explained by a poor ventilatory adaptation in 36.8% of cases, cardiac abnormalities in 23.7% and both in 7.7%. 6MWD was within normal at 83.7 +/- 15.6% of reference value. Neither peak, maximal workload nor 6MWD correlated with the results of PFTs. In patients with normal pulmonary function, the 6MWD had an 80% sensitivity at predicting a decrease in peak. The total SGRQ index of 51% represents the effect of dyspnoea on quality of life. We conclude that there is moderate impairment of maximal exercise capacity in one third of retired coal miners complaining of exercise dyspnoea, irrespective of PFTs results. We suggest that 6MWD could be used to detect a decreased exercise tolerance in these patients with normal PFTs, but should be followed up with a maximal cardiopulmonary exercise test if found to be abnormal.

Widespread cutaneous carcinomas associated with human papillomaviruses 5, 14 and 20 after introduction of methotrexate in two long-term PUVA-treated patients.

BACKGROUND: PUVA treatment for patients with severe psoriasis has been demonstrated to be highly effective. However, an increased risk of nonmelanoma and melanoma skin cancers has been reported. It is generally accepted that the risk of squamous-cell carcinoma (SCC) is significantly increased in patients with long-term PUVA therapy. The role of methotrexate (MTX) and infection with oncogenic human papillomaviruses which may act as cocarcinogens is poorly documented. CASE REPORTS: Two cases of multiple SCCs associated with numerous PUVA keratoses and PUVA freckles after long-term PUVA therapy and subsequent treatment with MTX are presented. In 1 case, the tumor progressed to metastatic SCC. Tumors and scrapings of psoriatic skin lesions were analyzed for the presence of oncogenic human papillomavirus (HPV) genotypes. The genotype of HPV-5, -14 and -20 was detected in scrapings and skin tumors using PCR amplification. CONCLUSION: These observations support the concept that long-term PUVA treatment is carcinogenic and rise questions concerning an additional influence of MTX in the development and progression of skin cancer. The risk of metastatic SCC seems to be underestimated in high-dose PUVA-treated patients due to longer latency for developing metastases and the small number of studies with long-term follow-up. Treatment with MTX should be considered cautiously in patients previously exposed to high doses of PUVA. The presence of oncogenic HPVs in carcinomas and psoriatic skin lesions detected only with the highly sensitive nested PCR method is not necessarily a proof of their implication in skin carcinogenesis.