No abstract

A closed-loop glycemic control system using an artificial pancreas has been applied with many clinical benefits in Japan since 1987. To update this system incorporating user-friendly features, we developed a novel artificial pancreas (STG-55). The purpose of this study was to evaluate STG-55 for device usability, performance of blood glucose measurement, glycemic control characteristics in vivo in animal experiments, and evaluate its clinical feasibility. There are several features for usability improvement based on the design concepts, such as compactness, display monitor, batteries, guidance function, and reduction of the preparation time. All animal study data were compared with a clinically available artificial pancreas system in Japan (control device: STG-22). We examined correlations of both blood glucose levels between two groups (STG-55 vs. control) using Clarke's error grid analysis, and also compared mean glucose infusion rate (GIR) during glucose clamp. The results showed strong correlation in blood glucose concentrations (Pearson's product-moment correlation coefficient: 0.97; n = 1636). Clarke's error grid analysis showed that 98.4% of the data fell in Zones A and B, which represent clinically accurate or benign errors, respectively. The difference in mean GIRs was less than 0.2 mg/kg/min, which was considered not significant. Clinical feasibility study demonstrated sufficient glycemic control maintaining target glucose range between 80 and 110 (mg/dL), and between 140 and 160 without any hypoglycemia. In conclusion, STG-55 was a clinically acceptable artificial pancreas with improved interface and usability. A closed-loop glycemic control system with STG-55 would be a useful tool for surgical and critical patients in intensive care units, as well as diabetic patients.

Previously, one of the authors developed a noninvasive measurement method of acceleration and deceleration during the expansion process of the blood vessel wall under pulsatile pressure flow by measuring the strain rate of the blood vessel wall using a supersonic Doppler effect sensor aided by computer analysis (DPC method). In this paper, on the basis of the analysis of chaos theory, that is, the complexity of science, the unstable behavior of the blood vessel wall with an aneurysm was investigated by identifying the characteristic DPC wave forms induced by the onset and progression of aneurysm. These results showed that unstable dynamic behavior of the blood vessel wall occurs due to the progression of the aneurysm. Furthermore, using the theoretical analysis of chaos, this unstable behavior of the blood vessel wall was quantified and the fundamental principle of a noninvasive diagnostic method of the progressive degree of aneurysm was proposed. IntroductionThe supersonic Doppler effect sensor has been used to measure blood flow velocity as a non-invasive method 1, 2) and some researches into its clinical application have been conducted [3][4][5] . However, whether the output from the Doppler effect sensor really detects blood flow velocity remains a problem.Theoretically, when the Doppler effect sensor is set perpendicular to the blood flow direction, that is, perpendicular to the blood vessel, the output will correspond to the expansion velocity of the blood vessel wall, because it detects the frequency of Doppler-shifted supersonic scattered from the blood vessel wall.One of the authors developed a noninvasive measurement method of acceleration and deceleration of the blood vessel wall during its expansion process under pulsatile pressure flow by measuring the strain rate of the blood vessel wall using a supersonic Doppler effect sensor 6) . On the basis of this method, a noninvasive quantitative diagnostic method of the progressive degree of atherosclerosis has been developed by obtaining accelerating and decelerating responses of the blood vessel wall under pulsatile pressure flow (DPC method) 7,8) . Furthermore, if noninvasive diagnosis of the onset and the progressive degree of the aneurysm becomes possible, the progressive degree of aneurysm can be shown quantitatively together with that of atherosclerosis and it will be useful in clinical application from the viewpoint of predicting the rupture time of the aneurysm, because not only the aneurysm itself Until now, researches into aneurysms, the clarification of blood flow behavior around an aneurysm have focused on treatment using fluid dynamics [9][10][11][12] . On the other hand, under pulsatile conditions, since the analysis of the deformation behavior of the blood vessel wall with an aneurysm is not feasible, there is little research into the dynamic behavior of the blood vessel wall with an aneurysm which is useful for clinical matters.Therefore, in this paper, on the basis of an chaos theory analysis 13) , that is, the complexity of science, the...

A 20-year-old woman with Kearns-Sayre syndrome (KSS) suddenly experienced two episodes of diabetic coma. She was studied to determine whether diabetes mellitus (DM) resulted from insulin resistance or from an insulin secretion abnormality, using the euglycemic glucose clamp technique and the glucagon tolerance test. She had a deficiency of insulin secretion from beta cells. It is important to recognize in practice the onset of DM in patients with mitochondrial myopathy. We would suggest that a genetic linkage or mitochondrial dysfunction may be responsible for the association of both disease states.

This clinical study aimed to compare a novel and conventional artificial pancreas (AP) used in surgical patients for perioperative glycemic control, with respect to usability, blood glucose measurements, and glycemic control characteristics. From July in 2010 to March in 2015, 177 patients underwent perioperative glycemic control using a novel AP. Among them, 166 patients were eligible for inclusion in this study. Intensive insulin therapy (IIT) targeting a blood glucose range of 80-110 mg/dL was implemented in 82 patients (49 %), and the remaining 84 patients (51 %) received a less-intensive regime of insulin therapy. Data were collected prospectively and were reviewed or analyzed retrospectively. A comparison study of 324 patients undergoing IIT for glycemic control using a novel (n = 82) or conventional AP (n = 242) was conducted retrospectively. All patients had no hypoglycemia. The comparison study revealed no significant differences in perioperative mean blood glucose level, achievement rates for target blood glucose range, and variability in blood glucose level achieved with IIT between the novel AP and conventional AP groups. The usability, performance with respect to blood glucose measurement, and glycemic control characteristics of IIT were comparable between novel and conventional AP systems. However, the novel AP was easier to manipulate than the conventional AP due to its smaller size, lower weight, and shorter time for preparation. In the near future, this novel AP system might be accepted worldwide as a safe and useful device for use in perioperative glycemic control.