Contrast agent-enhanced, free-breathing, three-dimensional coronary magnetic resonance angiography.

For free-breathing, high-resolution, three-dimensional coronary magnetic resonance angiography (MRA), the use of intravascular contrast agents may be helpful for contrast enhancement between coronary blood and myocardium. In six patients, 0.1 mmol/kg of the intravascular contrast agent MS-325/AngioMARK was given intravenously followed by double-oblique, free-breathing, three-dimensional inversion-recovery coronary MRA with real-time navigator gating and motion correction. Contrast-enhanced, three-dimensional coronary MRA images were compared with images obtained with a T2 prepulse (T2Prep) without exogenous contrast. The contrast-enhanced images demonstrated a 69% improvement in the contrast-to-noise ratio (6.6 +/- 1.1 vs. 11.1 +/- 2.5; P < 0.01) compared with the T2Prep approach. By using the intravascular agent, extensive portions (> 80 mm) of the native left and right coronary system could be displayed consistently with sub-millimeter in-plane resolution. The intravascular contrast agent, MS-325/AngioMARK, leads to a considerable enhancement of the blood/muscle contrast for coronary MRA compared with T2Prep techniques. The clinical value of the agent remains to be defined in a larger patient series. J. Magn. Reson. Imaging 1999;10:790-799.

Chlamydiaceae and Chlamydia-like organisms in free-living small mammals in Europe and Afghanistan.

Few data are available on the occurrence of chlamydial infections in wild small mammals. We investigated the significance of free-living small mammals as reservoirs or transmission hosts for microorganisms of the phylum/class Chlamydiae. We obtained 3,664 tissue samples from 911 animals in Switzerland, Germany, Austria, the Czech Republic, and Afghanistan. Samples included internal organs (n = 3,652) and feces (n = 12) from 679 rodents (order Rodentia) and 232 insectivores (order Soricomorpha) and were tested by three TaqMan® real-time PCRs specific for members of the family Chlamydiaceae and selected Chlamydia-like organisms such as Parachlamydia spp. and Waddlia spp. Only one of 911 (0.11%) animals exhibited a questionable positive result by Chlamydiaceae-specific real-time PCR. Five of 911 animals were positive by specific real-time PCR for Parachlamydia spp. but could not be confirmed by quantitative PCR targeting the Parachlamydia acanthamoebae secY gene (secY qPCR). One of 746 animals (0.13%) was positive by real-time PCR for Waddlia chondrophila. This result was confirmed by Waddlia secY qPCR. This is the first detection of Chlamydia-like organisms in small wildlife in Switzerland. Considering previous negative results for Chlamydiaceae in wild ruminant species from Switzerland, these data suggest that wild small mammals are unlikely to be important carriers or transport hosts for Chamydiaceae and Chlamydia-like organisms.

Drug uptake in a rodent sarcoma model after intravenous injection or isolated lung perfusion of free liposomal doxorubicin /

Rapport de synthèseDrug uptake in a rodent sarcoma model after intravenous injection or isolated lungperfusion of free/liposomal doxorubicinIntroductionLa distribution de doxorubicine libre et doxorubicin liposomale pegylée (Liporubicin?) a été comparée après administration intraveineuse ou application via perfusion isolée du poumon (ILP) dans le parenchyme pulmonaire et dans la tumeur des poumons de rongeurs, porteurs d'une tumeur sarcomateuse.Matériel et méthodeUne tumeur sarcomateuse unique a été générée dans le poumon gauche de 36 rongeurs (Fisher rats) suivie, 10 jours plus tard, par application de doxorubicine ou Liporubicin? soit par perfusion isolée du poumon (n = 20) ou administration intraveineuse (n = 12). Deux différentes concentrations ont été utilisées (100 μg et 400 pg) à doses équimolaires pour les deux formulations de doxorubicine. La concentration des agents cytostatiques ont été mesurées dans la tumeur et le parenchyme pulmonaire à l'aide de chromatographic (HPLC).RésultatsLes résultats indiquent que pour doxorubicine libre, le taux de concentration dans la tumeur et le parenchyme pulmonaire est 3 fois (dosage de 100 μ§) et 10 fois (dosage de 400 plus élevé après ILP par rapport à l'administration intraveineuse. En revanche, pour Liporubicin , le taux de concentration est similaire dans la tumeur et le parenchyme pulmonaire entre ILP et administration intraveineuse, pour les deux doses appliquées.ConclusionPour ILP et administration intraveineuse, le ratio entre accumulation de l'agent cytostatique dans la tumeur versus dans le parenchyme pulmonaire a été comparé pour les deux formulations de doxorubicine ainsi que pour les deux dosages. Pour les deux formulations et dosages de doxorubicine, ILP aboutit à un ratio plus élevé par rapport à l'administration intraveineuse. Cependant, pour les deux formulations et dosages de doxorubicine, ILP résulte également en une distribution de l'agent cytostatique plus hétérogène dans le parenchyme pulmonaire comparé à l'administration intraveineuse.En résumé, l'application de doxorubicine par ILP aboutit donc à une accumulation tumorale élevée et à une augmentation du ratio tumeur-parenchyme pulmonaire, mais en même temps également à une distribution plus hétérogène dans le parenchyme pulmonaire par rapport à l'application intraveineuse. Ceci a été observé pour les deux formulations de doxorubicine et pour les deux dosages appliqué.

Social organization and mating system of free-ranging, greater white-toothed shrews, Crocidura russula

Indirect evidence from trapping suggests that Crocidura russula is less solitary and territorial than other shrews. To study the social organization and mating system, free-ranging adult and juvenile C. russula were tracked simultaneously throughout the year using a radioactive tracking technique. Coincident rest, coincident activity and home range overlap were measured. During winter, all individuals used the same communal nest and spent on average 84% of their total rest in coincident rest. This led to a large home range overlap (52% on average). Coincident activity was low (2% on average). At the onset of the reproductive season the females became, territorial and shared their nest with only one male. During pair formation, coincident activity and home range overlap were significantly greater between than within sexes. The social organization of C. russula appeared to be strongly influenced by season and differed in this respect from the other species in the genus Sorex which are territorial throughout the year.

Wheat germ cell-free expression: Two detergents with a low critical micelle concentration allow for production of soluble HCV membrane proteins.

Membrane proteins are notoriously difficult to express in a soluble form. Here, we use wheat germ cell-free expression in the presence of various detergents to produce the non-structural membrane proteins 2, 4B and 5A of the hepatitis C virus (HCV). We show that lauryl maltose neopentyl glycol (MNG-3) and dodecyl octaethylene glycol ether (C12E8) detergents can yield essentially soluble membrane proteins at detergent concentrations that do not inhibit the cell-free reaction. This finding can be explained by the low critical micelle concentration (CMC) of these detergents, which keeps the monomer concentrations low while at the same time providing the necessary excess of detergent concentration above CMC required for full target protein solubilization. We estimate that a tenfold excess of detergent micelles with respect to the protein concentration is sufficient for solubilization, a number that we propose as a guideline for detergent screening assays.

Floating arterial thrombus related stroke treated by intravenous thrombolysis.

BACKGROUND: The effects of intravenous thrombolysis on floating thrombi in cervical and intracranial arteries of acute ischemic stroke patients are unknown. Similarly, the best prevention methods of early recurrences remain controversial. This study aimed to describe the clinical and radiological outcome of thrombolyzed strokes with floating thrombi. METHODS: We retrospectively analyzed all thrombolyzed stroke patients in our institution between 2003 and 2010 with floating thrombi on acute CT-angiography before the intravenous thrombolysis. The floating thrombus was diagnosed if an elongated thrombus of at least 5 mm length, completely surrounded by contrast on supra-aortic neck or intracerebral arteries, was present on CT-angiography. Demographics, vascular risk factors, and comorbidities were recorded and stroke etiology was determined after a standardized workup. Repeat arterial imaging was performed by CTA at 24 h or before if clinical worsening was noted and then by Doppler and MRA during the first week and at four months. RESULTS: Of 409 thrombolyzed stroke patients undergoing acute CT Angiography, seven (1.7%) had a floating thrombus; of these seven, six had it in the anterior circulation. Demographics, risk factors and stroke severity of these patients were comparable to the other thrombolyzed patients. After intravenous thrombolysis, the floating thrombi resolved completely at 24 h in four of the patients, whereas one had an early recurrent stroke and one developed progressive worsening. One patient developed early occlusion of the carotid artery with floating thrombus and subsequently a TIA. The two patients with a stable floating thrombus had no clinical recurrences. In the literature, only one of four reported cases were found to have a thrombolysis-related early recurrence. CONCLUSIONS: Long-term outcome seemed similar in thrombolyzed patients with floating thrombus, despite a possible increase of very early recurrence. It remains to be established whether acute mechanical thrombectomy could be a safer and more effective treatment to prevent early recurrence. However, intravenous thrombolysis should not be withheld in eligible stroke patients.

Responsiveness of astrocytes in serum-free aggregate cultures to epidermal growth factor: dependence on the cell cycle and the epidermal growth factor concentration.

Serum-free aggregating cell cultures of fetal rat telencephalon treated with low doses (0.5 nM) of epidermal growth factor (EGF) showed a small, transient increase in DNA synthesis but no significant changes in total DNA and protein content. By contrast, treatment with high doses (13 nM) of EGF caused a marked stimulation of DNA synthesis as well as a net increase in DNA and protein content. The expression of the astrocyte-specific enzyme, glutamine synthetase, was greatly enhanced both at low and at high EGF concentrations. These results suggest that at low concentration EGF stimulates exclusively the differentiation of astrocytes, whereas at high concentration, EGF has also a mitogenic effect. Nonproliferating astrocytes in cultures treated with 0.4 microM 1-beta-D-arabinofuranosyl-cytosine were refractory to EGF treatment, indicating that their responsiveness to EGF is cell cycle-dependent. Binding studies using a crude membrane fraction of 5-day cultures showed a homogeneous population of EGF binding sites (Kd approximately equal to 2.6 nM). Specific EGF binding sites were found also in non-proliferating (and nonresponsive) cultures, although they showed slightly reduced affinity and binding capacity. This finding suggests that the cell cycle-dependent control of astroglial responsiveness to EGF does not occur at the receptor level. However, it was found that the specific EGF binding sites disappear with progressive cellular differentiation.

Should we await IFN-free regimens to treat HCV genotype 1 treatment-naive patients? A cost-effectiveness analysis (ANRS 95141).

BACKGROUND & AIMS: In treatment-naive patients mono-infected with genotype 1 chronic HCV, treatments with telaprevir/boceprevir (TVR/BOC)-based triple therapy are standard-of-care. However, more efficacious direct-acting antivirals (IFN-based new DAAs) are available and interferon-free (IFN-free) regimens are imminent (2015). METHODS: A mathematical model estimated quality-adjusted life years, cost and incremental cost-effectiveness ratios of (i) IFN-based new DAAs vs. TVR/BOC-based triple therapy; and (ii) IFN-based new DAAs initiation strategies, given that IFN-free regimens are imminent. The sustained virological response in F3-4/F0-2 was 71/89% with IFN-based new DAAs, 85/95% with IFN-free regimens, vs. 64/80% with TVR/BOC-based triple therapy. Serious adverse events leading to discontinuation were taken as: 0-0.6% with IFN-based new DAAs, 0% with IFN-free regimens, vs. 1-10% with TVR/BOC-based triple therapy. Costs were euro60,000 for 12weeks of IFN-based new DAAs and two times higher for IFN-free regimens. RESULTS: Treatment with IFN-based new DAAs when fibrosis stage ⩾F2 is cost-effective compared to TVR/BOC-based triple therapy (euro37,900/QALY gained), but not at F0-1 (euro103,500/QALY gained). Awaiting the IFN-free regimens is more effective, except in F4 patients, but not cost-effective compared to IFN-based new DAAs. If we decrease the cost of IFN-free regimens close to that of IFN-based new DAAs, then awaiting the IFN-free regimen becomes cost-effective. CONCLUSIONS: Treatment with IFN-based new DAAs at stage ⩾F2 is both effective and cost-effective compared to TVR/BOC triple therapy. Awaiting IFN-free regimens and then treating regardless of fibrosis is more efficacious, except in F4 patients; however, the cost-effectiveness of this strategy is highly dependent on its cost.

Impact of navigator timing on free-breathing submillimeter 3D coronary magnetic resonance angiography.

The purpose of this study was to investigate the impact of navigator timing on image quality in navigator-gated and real-time motion-corrected, free-breathing, three-dimensional (3D) coronary MR angiography (MRA) with submillimeter spatial image resolution. Both phantom and in vivo investigations were performed. 3D coronary MRA with real-time navigator technology was applied using variable navigator time delays (time delay between the navigator and imaging sequences) and varying spatial resolutions. Quantitative objective and subjective image quality parameters were assessed. For high-resolution imaging, reduced image quality was found as a function of increasing navigator time delay. Lower spatial resolution coronary MRA showed only minor sensitivity to navigator timing. These findings were consistent among volunteers and phantom experiments. In conclusion, for submillimeter navigator-gated and real-time motion-corrected 3D coronary MRA, shortening the time delay between the navigator and the imaging portion of the sequence becomes increasingly important for improved spatial resolution.

Label-free cytotoxicity screening assay by digital holographic microscopy

Abstract We introduce a label-free technology based on digital holographic microscopy (DHM) with applicability for screening by imaging, and we demonstrate its capability for cytotoxicity assessment using mammalian living cells. For this first high content screening compatible application, we automatized a digital holographic microscope for image acquisition of cells using commercially available 96-well plates. Data generated through both label-free DHM imaging and fluorescence-based methods were in good agreement for cell viability identification and a Z'-factor close to 0.9 was determined, validating the robustness of DHM assay for phenotypic screening. Further, an excellent correlation was obtained between experimental cytotoxicity dose-response curves and known IC values for different toxic compounds. For comparable results, DHM has the major advantages of being label free and close to an order of magnitude faster than automated standard fluorescence microscopy.

Marker-free phase nanoscopy

We introduce a microscopic method that determines quantitative optical properties beyond the optical diffraction limit and allows direct imaging of unstained living biological specimens. In established holographic microscopy, complex fields are measured using interferometric detection, allowing diffraction-limited phase measurements. Here, we show that non-invasive optical nanoscopy can achieve a lateral resolution of 90 nm by using a quasi-2 pi-holographic detection scheme and complex deconvolution. We record holograms from different illumination directions on the sample plane and observe subwavelength tomographic variations of the specimen. Nanoscale apertures serve to calibrate the tomographic reconstruction and to characterize the imaging system by means of the coherent transfer function. This gives rise to realistic inverse filtering and guarantees true complex field reconstruction. The observations are shown for nanoscopic porous cell frustule (diatoms), for the direct study of bacteria (Escherichia coil), and for a time-lapse approach to explore the dynamics of living dendritic spines (neurones).

Previous microvascular decompression decreases the chances of pain free in patients treated with Gamma Knife radiosurgery for TIC

Object: The authors sought to establish whether the safety-efficacy of Gamma Knife radiosurgery (GKRS) as a second treatment for intractable trigeminal neuralgia (ITN) are influenced by prior microvascular decompression (MVD) which remains, for some of the authors, the reference technique. Methods: Between July 1992 and November 2010, 737 patients have been operated with GKRS for ITN and prospectively evaluated in Timone University Hospital in Marseille, France. Among these, 54 patients had a previous MVD history. Radiosurgery using a Gamma Knife (model B or C or Perfexion) was performed relying on both MR and CT targeting. A single 4 mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.6 mm (range 3.9- 11.9) anteriorly to the emergence of the nerve (retrogasserian target). A median maximum dose of 85 Gy (range 70-90) was delivered. Are further analyzed only 45 patients with previous MVD and a follow-up longer than one year (the patients with megadolichobasilar artery compression and multiple sclerosis were excluded). Results: The median age in this series was 56.75 years (range 28.09-82.39). The median follow-up period was 39.48 months (range 14.10-144.65). All the patients had a past history of surgery, with at least one previous failed MVD, but also a radiofrequency lesion (RFL) in 16 (35.6%) patients, balloon microcompression in 7 (15.6%) patients and glycerol rhizotomy in 1 case (2.2%). Thirty-five patients (77.8%) were initially pain free in a median time of 14 days (range 0, 180). Patients from this group had less probability of being pain free compared to our global population of essential trigeminal neuralgia without previous MVD history (p=0.010, hazard ratio of 0.64). Their probability of remaining pain free at 3, 5, 7 and 10 years was 66.5%, 59.1%, 59.1% and 44.3%, respectively. Twelve patients (34.3%) initially pain free experienced a recurrence with a median delay of 31.21 months (range 3.40-89.93). The hypoesthesia actuarial rate at 1 year was 9.1% and remained stable till 12 years with a median delay of onset of 8 months (range 8-8). Conclusions: Retrogasserian GKRS proofed to be safe and effective on the long-term basis even after failed previous MVD. Even if the initial result of pain free was of only 77.8%, the toxicity was low with only 9.1% hypoesthesia. No patient reported a bothersome hypoesthesia. The probability of maintaining pain relief in long-term was of 44.3% at 10 years.