Retroviral infection and selection of culture-derived platelets allows study of the effect of transgenes on platelet physiology ex vivo and on thrombus formation in vivo

Background- We recently reported the development of culture-derived (CD) platelets with the aim to express any protein of interest in these platelets. We now report a specific protocol of retroviral infection into the progenitor cells and subsequent selection, which allows to generate large amounts of highly homogenous transgene-expressing CD platelets and to study transgene function rapidly and reliably at large-scale ex vivo and in vivo settings. METHODS AND RESULTS: After retroviral infection and selection, the activation-dependent expression profile of surface markers, aggregation, and granule release were investigated. The function of transgene-expressing CD platelets, the precursor cells of which had been retrovirally infected, compared well to noninfected CD platelets or freshly isolated platelets. Hence, the retroviral infection protocol did not alter platelet physiology. In contrast, adenoviral infection of precursors to CD platelets resulted in marked functional alterations that obviated their use in analytic experiments. Additionally, sufficient amounts of selected CD platelets were generated to warrant intravenous injections into living mice. This approach permitted study of their adhesive profile at endothelial lesions and their effect on thrombus formation in vivo by intravital videofluorescence microscopy. CONCLUSIONS: The novel selection method allowed us to produce recombinant transgene-expressing platelets in sufficient amounts to study genetically modified platelets in vitro and in vivo.     

Secretory products from human adipocytes impair endothelial function via nuclear factor kappaB

Hyperplasia and hypertrophy of fat cells can be found in obesity, and increased adiposity is associated with endothelial dysfunction as an early event of atherosclerosis. However, it is unclear whether human adipocytes directly influence endothelial function. To study the crosstalk between fat and endothelial cells, human umbilical venous endothelial cells (HUVECs), and human coronary artery endothelial cells (HCAECs) were cultured in infranatants (Adipo) of primary differentiated human adipocytes. Interestingly, incubation of HUVECs and HCAECs with Adipo significantly increased monocyte adhesion 7.3 and 2.2-fold, respectively. VCAM-1, ICAM-1, and E-selectin in HUVECs were upregulated 3.9, 3.0, and 9.5-fold, respectively, under these conditions. Furthermore, Adipo significantly stimulated NFkappaB activity 1.9-fold. The NFkappaB inhibitor MG-132 and heat inactivation significantly reversed Adipo-stimulated monocyte adhesion. TNFalpha-neutralizing antibodies partly reversed Adipo-induced monocyte adhesion. In contrast, thiazolidinedione-pretreatment of human adipocytes did not alter the effects of Adipo. Adipo did not show cytotoxic effects. Taken together, we demonstrate that endothelial dysfunction is induced by adipocyte-secreted factors via NFkappaB partly dependent on TNFalpha.     

Prospective pilot evaluation of a new needle prototype for endoscopic ultrasonography-guided fine-needle aspiration: comparison of cytology and histology yield

OBJECTIVES: Endoscopic ultrasonography (EUS) with the adjunct of EUS-guided fine needle aspiration has become an important diagnostic modality in gastroenterologic oncology. EUS-guided fine needle aspiration mainly relies on cytology; data are scarce that compare cytology and histology. While testing a 22-gauge prototype needle, we prospectively compared the yield for both. METHODS: Forty-two consecutive patients (27 male, 15 female; mean age 59.2 years, range: 17-90 years) were included. In each patient we aimed to make two needle passes, and if the material acquired appeared insufficient macroscopically (no in-room cytopathology was available), further passes were done. The material was sent for cytological and histological assessment. RESULTS: A median number of two passes (range: 2-3) were uneventfully performed for pancreatic lesions (n=30), mediastinal and other lymph nodes/masses (n=8) and various other lesions (n=4) and yielded adequate material for cytology, histology or at least one of the two investigations in 62, 67 and 74% of patients, respectively. No false positive results were found (specificity 100%). Sensitivities were 58.6 and 65.5%, respectively, for cytology and histology alone; combined assessment increased sensitivity to 79.3%. When adjusted values were calculated, based only on those cases with adequate material, sensitivity was 89.5% for cytology and 85.7% for histology, and increased to 100% with combined assessment. CONCLUSION: The new needle achieves sensitivities similar to those previously reported with no significant differences in sensitivity between cytology and histology. More effective tissue acquisition methods must be sought to improve overall results.     

Safety and Pharmacokinetics of Isavuconazole as Antifungal Prophylaxis in Acute Myeloid Leukemia Patients with Neutropenia: Results of a Phase 2, Dose Escalation Study

Isavuconazole is a novel broad-spectrum triazole antifungal agent. This open-label dose escalation study assessed the safety and pharmacokinetics of intravenous isavuconazole prophylaxis in patients with acute myeloid leukemia who had undergone chemotherapy and had preexisting/expected neutropenia. Twenty-four patients were enrolled, and 20 patients completed the study. The patients in the low-dose cohort (n = 11) received isavuconazole loading doses on day 1 (400/200/200 mg, 6 h apart) and day 2 (200/200 mg, 12 h apart), followed by once-daily maintenance dosing (200 mg) on days 3 to 28. The loading and maintenance doses were doubled in the high-dose cohort (n = 12). The mean ± standard deviation plasma isavuconazole areas under the concentration-time curves for the dosing period on day 7 were 60.1 ± 22.3 μg · h/ml and 113.1 ± 19.6 μg · h/ml for the patients in the low-dose and high-dose cohorts, respectively. The adverse events in five patients in the low-dose cohort and in eight patients in the high-dose cohort were considered to be drug related. Most were mild to moderate in severity, and the most common adverse events were headache and rash (n = 3 each). One patient in the high-dose cohort experienced a serious adverse event (unrelated to isavuconazole treatment), and two patients each in the low-dose and high-dose cohorts discontinued the study due to adverse events. Of the 20 patients who completed the study, 18 were classified as a treatment success. In summary, the results of this analysis support the safety and tolerability of isavuconazole administered at 200 mg and 400 mg once-daily as prophylaxis in immunosuppressed patients at high risk of fungal infections. (This study is registered at ClinicalTrials.gov under registration number {"type":"clinical-trial","attrs":{"text":"NCT00413439","term_id":"NCT00413439"}}NCT00413439.)     

Single-ring ablation compared with standard circumferential pulmonary vein isolation using remote magnetic catheter navigation

Purpose

In ablation of atrial fibrillation, the single-ring method aims for isolation of the posterior wall of the left atrium (LA) including the pulmonary veins (PVs) but avoiding posterior LA lesions. The aim of this randomized prospective study was to evaluate safety and efficacy of remote magnetic navigation (RMN)-guided single-ring ablation strategy as compared to standard RMN-guided circumferential PV ablation (PVA).

Methods

Eighty consecutive patients undergoing PVA were enrolled prospectively and randomized equally into two study groups. RMN using the Stereotaxis system and open-irrigated 3.5-mm ablation catheters were used with a 3D mapping system in all procedures. Forty patients underwent RMN-guided single-ring ablation, and 40 patients received RMN-guided circumferential PVA.

Results

In the circumferential group, 3.3?±?1.1 PVs were successfully isolated at the end of the procedure as compared to 3.1?±?1.3 in the single-ring (box) group (p?=?0.38). All patients in the box group required additional posterior lesions in order to achieve electrical isolation of the PVs. Single-ring ablation was associated with longer procedure duration (p?=?0.01) and ablation time (p?=?0.001). After a single procedure, the proportion of patients free of any atrial tachycardia (AT)/atrial fibrillation (AF) episode at 12-month follow-up was 57 % in the box group and 58 % in the circ group. Using RMN, only minor complications have been observed.

Conclusions

RMN-guided single-ring PVA provides comparable acute and long-term success rates as compared to RMN-guided circumferential PVA but requires additional posterior lesions to achieve PV isolation and increased procedure and ablation time. Procedural complication rates are low when using RMN.     

Anandamide produced by Ca2+-insensitive enzymes induces excitation in primary sensory neurons

The endogenous lipid agent N-arachidonoylethanolamine (anandamide), among other effects, has been shown to be involved in nociceptive processing both in the central and peripheral nervous systems. Anandamide is thought to be synthesised by several enzymatic pathways both in a Ca²⁺-sensitive and Ca²⁺-insensitive manner, and rat primary sensory neurons produce anandamide. Here, we show for the first time, that cultured rat primary sensory neurons express at least four of the five known Ca²⁺-insensitive enzymes implicated in the synthesis of anandamide, and that application of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-arachidonoyl, the common substrate of the anandamide-synthesising pathways, results in anandamide production which is not changed by the removal of extracellular Ca²⁺. We also show that anandamide, which has been synthesised in primary sensory neurons following the application of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-arachidonoyl induces a transient receptor potential vanilloid type 1 ion channel-mediated excitatory effect that is not inhibited by concomitant activation of the cannabinoid type 1 receptor. Finally, we show that sub-populations of transient receptor potential vanilloid type 1 ion channel-expressing primary sensory neurons also express some of the putative Ca²⁺-insensitive anandamide-synthesising enzymes. Together, these findings indicate that anandamide synthesised by primary sensory neuron via a Ca²⁺-insensitive manner has an excitatory rather than an inhibitory role in primary sensory neurons and that excitation is mediated predominantly through autocrine signalling. Regulation of the activity of the Ca²⁺-insensitive anandamide-synthesising enzymes in these neurons may be capable of regulating the activity of these cells, with potential relevance to controlling nociceptive processing.