Rapid generation of functional engineered 3D human neuronal assemblies: network dynamics evaluated by micro-electrodes arrays.

Objective.In this work we adapted a protocol for the fast generation of human neurons to build 3D neuronal networks with controlled structure and cell composition suitable for systematic electrophysiological investigations.Approach.We used biocompatible chitosan microbeads as scaffold to build 3D networks and to ensure nutrients-medium exchange from the core of the structure to the external environment. We used excitatory neurons derived from human-induced pluripotent stem cells (hiPSCs) co-cultured with astrocytes. By adapting the well-established NgN2 differentiation protocol, we obtained 3D engineered networks with good control over cell density, volume and cell composition. We coupled the 3D neuronal networks to 60-channel micro electrode arrays (MEAs) to monitor and characterize their electrophysiological development. In parallel, we generated two-dimensional neuronal networks cultured on chitosan to compare the results of the two models.Main results.We sustained samples until 60 din vitro(DIV) and 3D cultures were healthy and functional. From the structural point of view, the hiPSC derived neurons were able to adhere to chitosan microbeads and to form a stable 3D assembly thanks to the connections among cells. From a functional point of view, neuronal networks showed spontaneous activity after a couple of weeks.Significance.We presented a particular method to generate 3D engineered cultures for the first time with human-derived neurons coupled to MEAs, overcoming some of the limitations related to 2D and 3D neuronal networks and thus increasing the therapeutic target potential of these models for biomedical applications.

A randomized, prospective trial of central venous ports connected to standard open-ended or Groshong catheters in adult oncology patients.

BACKGROUND: Implanted central venous access is practiced extensively in oncology; however, information on the relevance of using the device with a valved catheter (Groshong), compared with an open-ended catheter, is scarce. The authors investigated the two types of catheters in a randomized trial using the same type of subcutaneous port and evaluated efficacy as well as early and late complications. METHODS: Three hundred four patients with malignant disease (solid tumors) who were eligible to receive intravenous chemotherapy were accrued during a 15-month period. After providing informed consent, the patients were assigned randomly to implantation of a titanium and silicone, rubber port (Dome Port; Bard Inc., Salt Lake City, UT) attached either to an 8.0-F silastic Groshongtrade mark catheter tube (experimental group) or to a 9.6-F silastic open-ended catheter tube (control group). Both catheters were manufactured by Bard Inc. Implantation, care, and follow-up followed the same protocol guidelines until removal of the device, death, or ending of the study. Power and color Doppler ultrasound examinations of internal jugular and subclavian veins were performed at 1 month and at 4 months or at anytime when a venous thrombosis was suspected. RESULTS: Three hundred two patients (99.3%) were evaluable, 150 patients in the control group and 152 in the experimental group. The median follow-up was 237 days. There was a trend toward more early complications in the experimental group (5.9%; 95% confidence interval [95% CI], 2.7-10.9%) than in the control group (2.7%; 95% CI, 0.7-6.7%), although the difference was not statistically significant (P = 0.26). There was also a trend toward more late complications in the experimental group (17.1%; 95% CI, 11.5-24.1%) compared with the control group (10.7%; 95% CI, 6.2-16.7%; P = 0.13), although the difference, again, was not statistically significant. The most frequent late complication was the inability to draw blood samples (12.5% in the experimental group and 2% in the control group; P < 0.001). Sepsis was observed in 1 patient and in 3 patients and venous thrombosis was observed in 6 patients and in 11 patients in the experimental and control treatment groups, respectively (P value not significant). CONCLUSIONS: In the tested clinical setting, the use of a Groshong catheter was not superior to a traditional, open-ended device in terms of early and late complications of the implant and its use. The theoretical justification for its superiority for more efficient use of the implantable device could not be substantiated.

Ultrasound guided versus direct vein puncture in central venous port placement.

INTRODUCTION: This study will report our experience on positioning of totally implanted venous catheter system (port-a-cath) as compared to ultrasound guidance versus blind technique. MATERIALS AND METHODS: From July 1996 to November 1999 in the vascular suite of the Europen Institute of Oncology, 427 port-a-cath were implanted in patients with neoplastic disease. All devices were implanted through the subclavian vein. 198 with ultrasound guided puncture and 229 following anatomical landmarks. All patients underwent a close and specific clinical and instrumental follow-up to evaluate possible complications. RESULTS: Use of Ultrasound (US) in subclavian vein catheterization has reduced the number of puncture attempts, with a better patient complicance, allowing a faster procedure and reducing peri-procedural complications. Ultrasound technique has shown reduction in early complications. In fact in our experience we had no pneumothorax events by using ultrasound guidance, versus 11 events with blind technique. US has shown no reduction in late complications: 3 thrombosis versus 6 thrombosis with US guidance, and 3 fractured and embolized catheter versus 2 cases. Fibrin-cuff percentage was the same in the two groups with only 1 case, as the dislocation of the catheter tip in the jugular vein with 2 cases in both groups. Moreover US let us to avoid the arterial puncture and to perform a more peripheral puncture of the subclavian vein, reducing the risk of 'pinch-off' phenomenon and of haematoma, with no cases reported under US guidance versus 1 case respectively in direct vein puncture. CONCLUSIONS: US guided puncture of subclavian vein for the implantation of venous catheter system is faster by reducing procedure time, it is easier for the operator and safer for the patient than blind technique by exposing anatomical structures. Morevover US guidance reduces early complications and limits costs.