OBJECTIVEAttempts to build an artificial pancreas by using subcutaneous insulin delivery from a portable pump guided by an subcutaneous glucose sensor have encountered delays and variability of insulin absorption. We tested closed-loop intraperitoneal insulin infusion from an implanted pump driven by an subcutaneous glucose sensor via a proportional-integral-derivative (PID) algorithm.RESEARCH DESIGN AND METHODSTwo-day closed-loop therapy (except for a 15-min premeal manual bolus) was compared with a 1-day control phase with intraperitoneal open-loop insulin delivery, according to randomized order, in a hospital setting in eight type 1 diabetic patients treated by implanted pumps. The percentage of time spent with blood glucose in the 4.4–6.6 mmol/l range was the primary end point.RESULTSDuring the closed-loop phases, the mean ± SEM percentage of time spent with blood glucose in the 4.4–6.6 mmol/l range was significantly higher (39.1 ± 4.5 vs. 27.7 ± 6.2%, P = 0.05), and overall dispersion of blood glucose values was reduced among patients. Better closed-loop glucose control came from the time periods excluding the two early postprandial hours with a higher percentage of time in the 4.4–6.6 mmol/l range (46.3 ± 5.3 vs. 28.6 ± 7.4, P = 0.025) and lower mean blood glucose levels (6.9 ± 0.3 vs. 7.9 ± 0.6 mmol/l, P = 0.036). Time spent with blood glucose <3.3 mmol/l was low and similar for both investigational phases.CONCLUSIONSOur results demonstrate the feasibility of intraperitoneal insulin delivery for an artificial β-cell and support the need for further study. Moreover, according to a semiautomated mode, the features of the premeal bolus in terms of timing and amount warrant further research.

Glioblastoma multiform (GBM) are devastating brain tumors containing a fraction of multipotent stem-like cells which are highly tumorigenic. These cells are resistant to treatments and are likely to be responsible for tumor recurrence. One approach to eliminate GBM stem-like cells would be to force their terminal differentiation. During development, neurons formation is controlled by neurogenic transcription factors such as Ngn1/2 and NeuroD1. We found that in comparison with oligodendrogenic genes, the expression of these neurogenic genes is low or absent in GBM tumors and derived cultures. We thus explored the effect of overexpressing these neurogenic genes in three CD133(+) Sox2(+) GBM stem-like cell cultures and the U87 glioma line. Introduction of Ngn2 in CD133(+) cultures induced massive cell death, proliferation arrest and a drastic reduction of neurosphere formation. Similar effects were observed with NeuroD1. Importantly, Ngn2 effects were accompanied by the downregulation of Olig2, Myc, Shh and upregulation of Dcx and NeuroD1 expression. The few surviving cells adopted a typical neuronal morphology and some of them generated action potentials. These cells appeared to be produced at the expense of GFAP(+) cells which were radically reduced after differentiation with Ngn2. In vivo, Ngn2-expressing cells were unable to form orthotopic tumors. In the U87 glioma line, Ngn2 could not induce neuronal differentiation although proliferation in vitro and tumoral growth in vivo were strongly reduced. By inducing cell death, cell cycle arrest or differentiation, this work supports further exploration of neurogenic proteins to oppose GBM stem-like and non-stem-like cell growth.

We aimed to examine whether long-term use of benzodiazepines is associated with an accelerated decline of cognitive performances by using a statistical model specifically adapted to multivariate longitudinal bounded quantitative outcomes. The data came from the "Threecity" study, a French population based study. All the subjects were 65 years old or older at inclusion and had been followed-up for 7 years. The use of benzodiazepines and cognitive functioning were assessed at each examination phase (baseline, 2, 4 and 7 years). Cognitive decline was analyzed using a nonlinear multivariate mixed model with a latent process. This model makes it possible to assess change over time of the latent cognitive process underlying several neuropsychological tests: Mini Mental Status Examination, Isaacs Set test, Benton Visual Retention Test, and Trail Making Test (A and B), and to describe and account for their metrological properties. Analyses were adjusted for age, center, gender, education, socioprofessional status, depression, insomnia, high blood pressure, hypercholesterolemia, alcohol, tobacco consumption and physical activity. 969 subjects who reported taking benzodiazepines for 2, 4 or 7 consecutive years were compared to 4226 subjects who were non benzodiazepine users. Chronic use of benzodiazepine was significantly associated with a lower latent cognitive level (β=-1.79 SE=0.25 p=<0.001), but no association was found between chronic use and an acceleration of cognitive decline, neither on the latent cognitive process (β*time=0.010 SE=0.04 p=0.81), nor on specific neuropsychological tests. Our results suggest that chronic benzodiazepine use is associated with poorer cognitive performance but not with accelerated cognitive decline with age.