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At least 19 recordsLinked to original sources
PubMed1984

Insulin hypoglycaemia test guided by a glucose controlled insulin infusion system.

Insulin hypoglycaemia test (IHT) for assessment of hypothalamic-pituitary-adrenocortical (HPA) function in patients with pituitary tumours is usually performed by bolus injection of insulin, a procedure which includes the risk of overdosage and/or the need of repeated administration. This study describes that a glucose controlled insulin infusion system (GCIIS) permits to perform the IHT with standardized hypoglycaemia. Ten healthy volunteers and 10 patients with pituitary tumours were studied using the GCIIS (Biostator) on static control (Mode 1:1, BI 35, QI 10, RI 20, FI 300). Insulin administration was discontinued and the GCIIS used only for monitoring of blood glucose (BG), when BG had fallen below 40 mg/dl and initial clinical symptoms for hypoglycaemia were observed. In controls, the GCIIS guided IHT achieved a sufficient degree of hypoglycaemia (BG 27.6 +/- 2.0 mg/dl; mean +/- SEM) and physiological responses for GH (peak 49.4 +/- 6.7 ng/ml), Prl (peak 1766 +/- 614 microU/ml), ACTH (peak 76.0 +/- 8.7 pg/ml) and cortisol (peak 252 +/- 15 ng/ml). The total amount of insulin given was 0.115 +/- 0.012 U/kg. In the patients with pituitary tumours however, the required insulin dose varied markedly from 0.090 (pituitary insufficiency) to 0.340 U/kg (Cushing's syndrome). Minimum BG obtained was 32.5 +/- 1.9 mg/dl. Partial impairment of hypothalamic-pituitary function and, in particular, patients requiring exogenous cortisol supplementation during stress, could be identified. In conclusion, special advantages of the GCIIS-guided IHT are: Optimal insulin dosage with standardized hypoglycaemia due to automatic adjustment to the individual insulin sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1988

Intravenous insulin infusion system to determine insulin regimen in diabetics.

An algorithm for insulin infusion system to control blood glucose was derived from results of intravenous (i.v.) insulin infusion performed on 10 diabetics. I.v. insulin infusion was done on 14 diabetics for 24 hr using the algorithm, and blood glucose was controlled within the proper range in all cases; mean blood glucose was 130 +/- 42 mg/100 ml. During the examination, 4 of 14 cases did not need insulin infusion from midnight to the morning (type A) and 7 cases needed insulin infusion from midnight to the morning (type B). In 3 cases, insulin infusion was not needed at midnight, but blood glucose rose markedly in the early morning followed by insulin infusion (type C). The insulin regimen was determined according to the amount of insulin infused during the examination, dividing insulin dosages into two separate doses using semilente in the morning and a mixture of regular and lente insulin in the evening. In all the cases of type A and B, blood glucose was controlled well on the calculated regimen of insulin. However, good control of blood glucose was not obtained in 3 diabetics of type C. It is concluded that the algorithm is reliable in the estimation of the insulin infusion rate to control blood glucose in the diabetics, and the insulin regimen calculated from the result of intravenous insulin infusion is proper in about 78% of the diabetics.

Adult↗
PubMedDate not supplied

Comparison of porcine insulin and human insulin (Novo) using the glucose-controlled insulin infusion system, glucose-insulin dose-response curves, and the outpatient effectiveness of human insulin (Novo) in insulin-dependent diabetes.

The usefulness of human insulin (Novo) in the treatment of diabetes was studied in eight insulin-dependent diabetic patients. Evaluation was carried out through three methods: (1) glucose-controlled insulin infusion system on two separate days during the patients' ingestion of mixed meals; (2) euglycemic clamp method; and (3) evaluation of patients for 3 mo using short- and intermediate-acting insulins. Employing the glucose-controlled insulin infusion system resulted in mean daily insulin requirements of 84 +/- 9 U and 85 +/- 6 U SEM for porcine and human insulin, respectively (P = NS). Plasma glucose levels attained during the euglycemic clamp were 96 +/- 3 mg/dl. At each insulin infusion rate, the steady-state glucose infusion rates for porcine insulin were 1.12 +/- 0.22, 1.90 +/- 0.58, 4.28 +/- 0.61, and 9.37 +/- 0.66 mg/kg/min compared with 1.27 +/- 0.42, 2.38 +/- 0.20, 4.25 +/- 0.43, and 8.87 +/- 0.67 mg/kg/min for human insulin. No complications of either insulin preparation were observed in the 3-mo patient evaluation. Human insulin was associated with lower levels of circulating insulin antibody (P less than 0.03). In addition, hemoglobin A1c levels decreased from 8.4 to 6.9% (P less than 0.035), and normal hemoglobin A1c levels were maintained in patients using portable insulin infusion pumps.

Adult↗
PubMedDate not supplied

Comparison of the biologic activity of porcine and semisynthetic human insulins using the glucose-controlled insulin infusion system in insulin-dependent diabetes.

Semisynthetic human insulin is prepared from porcine pancreas by chemical methods involving the substitution of porcine B-30 alanine with threonine. To compare the effectiveness of porcine and semisynthetic human insulins, eight insulin-dependent diabetic patients were evaluated during two separate periods using a glucose-controlled insulin infusion system. During each 36-h period, patients received either porcine or semisynthetic human insulin. Patients ingested mixed meals. The mean daily insulin requirements for porcine and semisynthetic human insulins were 84 +/- 9 U and 85 +/- 6 U (+/- SEM), respectively (P = NS). Mean blood glucose values were similar at 95 +/- 1 mg/dl for porcine and 101 +/- 3 mg/dl with semisynthetic human insulin (P = NS). Prior metabolic control or insulin antibody levels did not correlate with intravenous insulin requirements. These studies indicate that semisynthetic human insulin is as effective as porcine insulin in maintaining near-normal blood glucose control in short-term intravenous studies using artificial pancreas techniques in insulin-dependent diabetes.

Adult↗
PubMed1998

Insulin levels after portal and systemic insulin infusion differ in a dose-dependent fashion.

The role of the liver in the regulation of systemic insulin levels is not well understood. The reported extraction rates vary between 0 to 85%, and extraction of a constant fraction of 50% of the portally delivered insulin is generally assumed. In the present study, we have investigated the role of the liver in the regulation of systemic insulin levels in the normal rat. Insulin was infused into the portal vein of conscious and freely moving rats in doses of 20, 40, 80 pmol/min during 15 min to mimic the gradual release of insulin by the native endocrine rat pancreas. The profiles of plasma insulin and glucose levels in the systemic circulation were compared to those obtained after direct infusion into the systemic circulation. The effect of intraportal and direct systemic infusion on plasma insulin and blood glucose levels were virtually similar where 20 pmol/min was applied. But, these effects were different if the dose was 40 pmol/min, and this difference increased when the dose was increased to 80 pmol/min, since hypoglycemia was less severe and normoglycemia was restored more rapidly with portal than with systemic infusion. Thus, our results show that the fraction of intraportally infused insulin reaching the systemic circulation decreases with higher doses of insulin. This suggests that the liver contains adaptable mechanisms to reduce the systemic insulin levels.

Animals↗
PubMed1981

Effects of somatostatin added to insulin in a glucose-controlled insulin infusion system.

Five insulin treated diabetics were studied on three consecutive days. Overnight variable intravenous insulin infusions were used before each study to maintain normoglycaemia and to calculate the optimal basal insulin infusion rate (1.1 +/- 0.1 U/h) which ws then kept constant throughout the study day. A standard 400 kCal breakfast with 25 g xylose was given at 0800 h. When the blood glucose rose above 4.1 mmol/l, an external artificial pancreas was used to infuse either extra insulin (day INS) or somatostatin for either 3h (day som) or the entire 8h experimental period (day SOM). Peak post-prandial blood glucose values were similar on all three days. The blood glucose rebounded after the cessation of the somatostatin infusion on day som. Post-prandial blood xylose peaks were lowered by somatostatin on both days but rebounded after the cessation of the somatostatin infusion on day som. The area under the plasma and urinary xylose curves was lowered by somatostatin only on day SOM. Growth hormone and glucagon levels were not statistically different on all 3 days. Thus somatostatin, when added to an optimal insulin infusion, minimised the insulin requirements by slowing intestinal absorption, but led to rebound hyperglycaemia if not feed-back controlled.

Adult↗
PubMed1979

Feedback control dynamics for glucose controlled insulin infusion system.

Miles Laboratories has developed a Glucose Controlled Insulin Infusion System (GCIIS) designated by the Trademark (BIOSTATOR) as a tool to investigate the physiologic control parameters of carbohydrate metabolism and regulatory deficiencies in diabetes. It consists, in principle, of a rapid on-line glucose analyzer, a computer/controller for the calculation and control of insulin or dextrose infusion, and a multichannel infusion system. A silent printer records, on a minute-by-minute basis, the glucose value measured, the insulin and/or dextrose infusion rates, and the cumulative total of the insulin infused. The on-line glucose analyzer employs an electrochemical sensor with immobilized glucose oxidase and measures the hydrogen peroxide produced. Its linearity extends beyond 700 mg/dl glucose; it permits a rapid two-point calibration of the sensor and the overall calibration of the on-line analyzer without disconnecting the catheter from the patient. The system's response time, including blood sample transport from the patient, is less than 90 seconds with a blood loss of approximately 50 ml per 24 h. The insulin and dextrose infusions are governed by control algorithms; various mathematical models have been developed and employed toward improved feedback control dynamics. The rapid glucose analyzer eliminates the need for the calculation of a "predicted" glucose value and permits, instead, the use of a derivative function for dynamic control. A multichannel infusion system combines the principles of a peristaltic pump with the advantages of a precision pump performance and individual computer control for each of the pump channels.

Blood Glucose↗
PubMedDate not supplied

Developmental and application of insulin infusion profiles for therapy of type-I diabetics with portable insulin infusion systems.

We studied the insulin requirements of seven insulin-dependent diabetics applying a glucose controlled insulin infusion system. The data were transformed into individually programmed and rectangular profiles. The MAGE, a measure of blood sugar fluctuations, was significantly lower when individually programmed step profiles were used (P less than 0.005) than it was when rectangular profiles were applied: 57.7 +/- 24.8 mg/dl vs 89.0 +/- 42.9 mg/dl. The average of measured blood glucose levels was significantly lower in individually programmed infusion profiles (P less than 0.025). The combination of individually programmed profiles and preprandial insulin bolus significantly reduced the postprandial blood glucose level and increase (P less than 0.001). Our investigations suggest that individually programmed insulin infusion profiles are able to smooth blood glucose fluctuations. When combined with an initial insulin bolus they may lead to a reduced insulin consumption after meals.

Adult↗
PubMed1982

Glucose control in mobile type 1 (insulin-dependent) diabetic patients by means of a semi-automatic feedback controlled insulin infusion system.

A portable insulin dosing device (Siemens) was used together with a programmable pocket calculator and a glucose analyzer for short-term adaptation of continuous intravenous insulin infusion to blood glucose alterations. A special algorithm was developed which utilizes a given blood glucose value and the glucose rate of change obtained from two to four consecutive samples as input variables. In contrast to current techniques of feedback-regulation, which require continuous glucose monitoring, intermittent blood sampling allows greater mobility of patients. With the semi-automatic feedback system, euglycaemic control was obtained for 12-h periods in ten Type 1 (insulin-dependent) diabetic patients (maximum value 9.50 mmol/l, minimum value 2.83 mmol/l). Severe hypoglycaemia occurred in no case and additional control by glucose infusion appeared to be unnecessary. Light exercise after termination of insulin dose for standard meals led to glycaemic excursions with a rapid decrease (mean 1.08 +/- 0.09 mmol/l), followed by a rebound (0.59 +/- 0.07 mmol/l) in each patient. The amplitude of these excursions decreased with increasing distance from the peak of the meal dose. Comparison of feedback-control alone with feedback by glucose plus preprogrammed dose (4 U/h) at the onset of the test meal revealed lower post-prandial glucose levels (post-prandial maximum +/- SEM: 6.49 +/- 0.18 versus 7.71 +/- 0.79 mmol/l) and a lower infusion rate of insulin for the combined regimen (mean post-prandial maximum +/- SEM: 8.4 +/- 1.2 versus 12.0 +/- 0 IU/h). The system is useful for programming of portable infusion devices and studies based on euglycaemic control in unrestrained patients.

Adult↗
PubMed1997

Stability of insulin lispro in insulin infusion systems.

OBJECTIVE: To test stability of insulin lispro in two insulin infusion systems over 48 h. RESEARCH DESIGN AND METHODS: We used reverse-phase and size-exclusion high-performance liquid chromatography (HPLC) to determine the purity, potency, and degree of polymerization of U100 insulin lispro (Humalog) after 24- and 48-h pump cycles conducted at 37 degrees C in five Disetronic H-TRON V100 and five MiniMed 504 pumps. Pumps were set to deliver a basal rate of 0.5 U/h and 6-U boluses at t = 0, 4, 8, 24, 24.5, 28.5, 32.5, and 48 h during each cycle. The effluent was collected into 1-ml vials, pooled at 24 or 48 h, and stored at 4 degrees C until assay. After each 48-h run period of insulin delivery, assays for potency, polymer, and purity were performed on the pooled samples from each individual cycle. m-cresol content and the pooled reservoir content were assayed in the 48-h pooled samples. RESULTS: Insulin lispro retained full HPLC potency (delta < or = 4%) at 48 h, with no degradation of insulin lispro to des-amidoinsulin forms (24 or 48 h). No increase in pumped insulin polymer concentration was observed following 24 h of pump flow. Nonsignificant increases of < or =0.09% (Disetronic) and < or =0.15% (MiniMed) from initial concentrations of 0.18% (polymer divided by total insulin) were detected in three of five pump cycles at 48 h when compared with 37 degrees C paired controls. Nonsignificant decreases (<5 and 10%, Disetronic and MiniMed, respectively) of m-cresol content occurred in both systems following 48 h storage in each device, but sterility was not compromised by this decrease (initial m-cresol concentration, 3.15 mg/ml). Pump performance was without mechanical or electrical fault throughout the study Basal and bolus insulin delivery was evaluated three times daily and remained as expected. Occlusion of catheters by insulin precipitation did not occur, and no change in pH was observed following delivery. CONCLUSIONS: We conclude that insulin lispro is suitable for prolonged infusion in these two medical devices when syringes and catheters are replaced at 48-h intervals.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Comparison of biosynthetic human insulin and pork insulin during rest, food ingestion, and physical work in insulin-dependent diabetic subjects using a glucose controlled insulin infusion system.

In six insulin-dependent diabetic subjects, we investigated whether differences between biosynthetic human insulin (BHI) and pork insulin are present as measured by an automatic glucose controlled insulin infusion system (GCIIS) (Biostator). The parameters measured were basal insulin requirement and food-dependent insulin requirement, as well as the blood sugar-lowering and insulin-saving effect of standardized physical work. The results show that BHI does not reveal any differences with regard to the basal food-independent and food-dependent insulin requirement compared to pork insulin in insulin-requiring diabetic subjects. Delayed food-dependent initial rise in blood sugar and insulin during physical work, which was observed with BHI, does not show any differences in the integral over 180 min. These investigations confirm the results found in vitro and in animal experiments. At the same time, they indicate discrete differences in the activity spectrum.

Animals↗
PubMed1978

Development and evaluation of a glucose analyzer for a glucose controlled insulin infusion system ((Biostator).

The Glucose-Controlled Insulin Infusion System (Biostator) is a modular, computerized, feedback control system for dynamic control of blood glucose concentrations in diabetics. This on-line glucose analyzer for use with whole blood utilizes a novel enzyme (glucose oxidase)-membrane configuration and an electrochemical cell to measure the H202 generated. The analyzer exhibits both short- and long-range stability, and instrument response and analyte concentration are linearly related over the full range of clinical interest. The response is fast, accurate, and precise, and permits determination of blood glucose within 2 min from the moment the blood leaves the patient. Correlation studies were completed to show the agreement between the Biostator Glucose Analyzer and the FDA's recommended hexokinase/glucose-6-phosphate dehydrogenase procedure on whole blood (e.g., average per cent recovered for 11 concentrations between 250 and 900 mg/liter was: hexokinase, 95.6%, Biostator Analyzer, 95.9%; bias and SDd, respectively, at low, normal, and high glucose values were: 12 and 41 mg/liter at the 500 mg/liter level; 4 and 52 mg/liter at the 1000 mg/liter level, and 4 and 128 mg/liter at the 4000 mg/liter level). No appreciable interference is observed with above-normal concentrations of bilirubin, uric acid, creatinine, sodium salicylate, or dextran. Platelet adhesion, which tends to decrease the useful life of the membrane, has been significantly decreased.

Autoanalysis↗
PubMed1984

A comparison of the artificial pancreas (glucose controlled insulin infusion system) and a manual technique for assessing insulin sensitivity during euglycaemic clamping.

Two main methods are available for assessing insulin sensitivity with the hyperinsulinaemic euglycaemic clamp technique: one employs a glucose-controlled insulin infusion system (the Biostator) with automatic feedback control; the second depends on frequent glucose measurement and the use of an algorithm and a pocket calculator ('manual') to determine the glucose infusion rate. The amount of glucose infused is a measure of insulin sensitivity. The efficiency of the two methods was compared in nine normal subjects (seven lean, two obese). After an overnight fast subjects were infused with insulin at 50 mU X kg-1 X h-1 for 2 h; this rate was doubled during the first 10 min for the manual technique. Blood glucose averaged 4.7 +/- 0.1 and 4.8 +/- 0.1 mmol/l from 0 to 120 min for Biostator and manual techniques and did not deviate significantly from the desired level. Variability of the clamp was also similar over the same period (coefficient of variation 5.1 +/- 0.6% and 6.4 +/- 0.7%, Biostator and manual). Glucose infused to maintain steady state from 60 to 120 min was higher, however, with the manual than the Biostator method (5.7 +/- 0.6 versus 4.4 +/- 0.6 mg X kg-1 X min-1, p less than 0.01) even when the loading dose was omitted, although the two methods correlated closely (p less than 0.05). Glucose infusion rate varied more from minute to minute with the Biostator (coefficient of variation 28.8 +/- 3% versus 12.2 +/- 2.1%). Steady-state serum insulin levels (30-120 min) were the same during both methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Use of a glucose-controlled insulin infusion system in children and adolescents with insulin-dependent diabetes.

Seven children and adolescents (aged 8 to 23 years, mean 16 years) with poorly controlled insulin-dependent diabetes mellitus were evaluated with a glucose-controlled insulin infusion system (GCIIS) to determine whether its use could help define appropriate long-term insulin treatment regimens and increase patient understanding and compliance with such regimens. The GCIIS-derived insulin regimen was characterized by a mean insulin requirement of 1.0 +/- 0.1 units/kg/day, with 55% of the total insulin dose given in the morning and 45% in the evening. Forty-eight percent of the total insulin was short acting. Both clinical and biochemical indices of metabolic control (HbA1c levels) improved after insulin dose readjustment based on GCIIS data. The continuous documentation of blood glucose levels provided by the GCIIS was valuable in educating patients about the interrelationship between insulin, exercise, and diet. Using GCIIS data, patients were taught to apply the new regimen flexibly to variations in activity and diet. Thus, the GCIIS can aid in the management of selected children and adolescents with insulin-dependent diabetes millitus. Insulin patterns derived from its use suggest that a flexible, twice daily regimen characterized by nearly equal proportions of short- and intermediate-acting preparations may be beneficial for other pediatric patients.

Adolescent↗
PubMed1979

Metabolic studies during normoglycaemic clamping of insulin-dependent diabetics using a glucose-controlled insulin infusion system.

Metabolic rhythms have been studied in six insulin-dependent diabetics during subcutaneous insulin therapy, and during control of blood glucose concentration by a glucose-controlled insulin infusion system (GCIIS). In none of the subjects was blood glucose concentration consistently within the normal range during subcutaneous insulin therapy. In contrast, blood glucose concentration was within the normal range after 3.5 h of insulin delivery by the glucose-controlled insulin infusion system and remained in the normal range for the following 8 h through lunch and dinner. Mean blood glucose concentration during this time ranged from 5.31 to 7.90 mM. Following normalisation of blood glucose concentration, blood lactate and pyruvate were similar with both the GCIIS and subcutaneous insulin therapy. Post-prandial lactate peaks were delayed with the GCIIS. Alanine levels were consistently higher during control with the GCIIS compared with subcutaneous therapy, while blood ketone body and plasma NEFA levels were lower, and the premeal peaks in the lipid metabolites were delayed. It is not possible to conclude that attainment of normoglycaemia with the present generation of glucose-controlled insulin infusion systems in insulin-dependent diabetics is accompanied by total normalisation of intermediary metabolism.

Adult↗
PubMedDate not supplied

A semi-closed loop computer-assisted insulin infusion system. Hospital use for control of diabetes in patients.

Closed loop insulin delivery systems are impractical for widespread hospital use. Thus, a semi-closed loop computer-assisted insulin infusion system (CAIIS) was developed for the intravenous delivery of insulin. In its basal program, insulin delivery is determined by blood glucose measurements at intervals of three hours, while the open-loop meal program delivers 7.5 units over three hours. Control of meal-induced hyperglycaemia was satisfactory in six subjects with diabetes tested over two to four days, as was mean glycaemic control in the four non-obese subjects (7.1 +/- 0.8 mmol/L). To allow for variations in insulin sensitivity, an adjustment incrementing or decrementing the basal insulin delivery rate was applied according to the progressive blood glucose response. Empirical use of this adjustment resulted in good control (mean blood glucose level, 4.1-7.5 mmol/L) in 10 additional subjects with diabetes. This study demonstrates the potential usefulness of a semi-closed loop insulin infusion system.

Adult↗
PubMed1984

A double-blind study of the efficacy of neutral human and porcine insulin in type I diabetes using a glucose-controlled insulin infusion system.

The comparative potency of equimolar amounts of soluble porcine and semisynthetic human insulin were studied in ten patients with type 1 diabetes in acute experimental situations. In both situations residual subcutaneous insulin depots were eliminated by intramuscular treatment exclusively with soluble insulin four days before the experiments. Then, practically identical metabolic states were achieved by connecting the patients to a glucose-controlled insulin infusion system (Biostator) 12 hours before the study. In one study, 0.5 g/kg body weight of glucose was administered intravenously as a bolus, and thereafter insulin was infused at a rate of 1.0 mU/kg/min. The decline in blood glucose was rectilinear and identical for the two insulins: y = -1.18x + 206 and y = -1.17x + 205. The insulin effect is well below maximum, and a 10% increase in the infusion rate of insulin was easily detected. Although changes in blood glucose and pancreatic glucagon were identical, a significantly lower plasma growth hormone level was noted after human insulin infusion. In the second study, 24 hours of near-normoglycemia was attained by the glucose-controlled insulin infusion system, the patients being supine and having identical meals at identical intervals. The diurnal blood glucose, plasma growth hormone, and pancreatic glucagon patterns were identical and the total 24 hour insulin consumption was 47.7 +/- 3.5 units and 47.7 +/- 3.7 units for the two insulins.

Adult↗
PubMed1978

A glucose-controlled insulin infusion system for diabetic women during labour.

A glucose-controlled insulin infusion system was used to control blood glucose concentration during labour or caesarean section in six insulin-dependent diabetics. The mean blood glucose concentration during the four hours of labour immediately before delivery was 4.6-5.2 mmol/1 (82.9-93.7 mg/100 ml). Feedback control of insulin delivery by blood glucose concentration should decrease the risk of postpartum hypoglycaemia in the infant and allow normal obstetric management for the insulin-dependent diabetic in labour.

Adult↗