scholarly journals Control Limitations in Models of T1DM and the Robustness of Optimal Insulin Delivery

2018 ◽  
Vol 12 (5) ◽  
pp. 926-936 ◽  
Author(s):  
Christopher Townsend ◽  
Maria M. Seron ◽  
Graham C. Goodwin ◽  
Bruce R. King
Keyword(s):  
Clinical Practice ◽  
Blood Glucose ◽  
Glucose Metabolism ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Glucose Concentration ◽  
Artificial Pancreas ◽  
Parameter Uncertainties ◽  
Optimal Input ◽  
Glucose Profiles

Background: In insulin therapy, the blood glucose level is constrained from below by the hypoglycemic threshold, that is, the blood glucose level must remain above this threshold. It has been shown that this constraint fundamentally limits the ability to lower the maxima of the blood glucose level predicted by many mathematical models of glucose metabolism. However, it is desirable to minimize hyperglycemia as well. Hence, a desirable insulin input is one that minimizes the maximum glucose concentration while causing it to remain above the hypoglycemic, or higher, threshold. It has been shown that this input, which we call optimal, is characterized by glucose profiles for which either each maximum of the glucose concentration is followed by a minimum or each minimum is followed by a maximum. Methods: We discuss the implication of this inherent control limitation for clinical practice and test, through simulation, the robustness of the optimal input to a number of different model and parameter uncertainties. We further develop guidelines on how to design an optimal insulin input that is robust to such uncertainties. Results: The optimal input is in general not robust to uncertainties. However, a number of strategies may be used to ensure the blood glucose level remains above the hypoglycemic threshold and the maximum blood glucose level achieved is less than that achieved by standard therapy. Conclusions: An understanding of the limitations on the controllability of the blood glucose level is important for future treatment improvements and the development of artificial pancreas systems.

Simulation Work for the Control of Blood Glucose Level in Type 1 Diabetes Using Hovorka Equations

2015 ◽  
Vol 1113 ◽  
pp. 739-744 ◽  
Author(s):  
Nur Farhana binti Mohd Yusof ◽  
Ayub Md Som ◽  
Sherif Abdulbari Ali ◽  
Aqilah Liyana binti Abdul Halim Anuar
Keyword(s):  
Type 1 Diabetes ◽  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Artificial Pancreas ◽  
Parametric Programming ◽  
Diabetes Patient ◽  
Simulation Software ◽  
Time Dynamic

Recently, diabetes is known as one of non-communicable diseases that can lead to fatal if there is no further cure is to be taken especially in South-East Asia regions. An artificial pancreas is introduced to help diabetes patient controls their blood glucose level but the current device is not functioning as fully automated yet. In order to have fully automated artificial pancreas, a controller needs to be improved as the current controller is 33% less accuracy than required. This improvement will help Type 1 diabetes patient in managing their blood glucose level at recommended range. Besides, the presence of controller will help the patient to live normally as non-diabetes people. This research is done to study behaviours of variables in Hovorka model for Type 1 diabetes and to simulate the Hovorka equations. gPROMS software is used due to its speciality in real-time dynamic simulation, fast calculation in complex mathematical equations and capable to adapt multi-parametric programming and Model Predictive Control (MPC). The study is conducted using simulation software based on previous studies experimental data; focusing on the algorithm of the controller. The results illustrate the most active parameter in the model is the administration (bolus & infusion) of insulin.

scholarly journals Blood glucose level in rats with different behavioral activity in the dynamics of repeated stress exposures

2019 ◽  
Vol 27 (1) ◽  
pp. 10-19
Author(s):  
Anastasiya Yu. Abramova ◽  
Elena V. Koplik ◽  
Irina V. Alekseyeva ◽  
Sergey S. Pertsov
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Stress Factors ◽  
Behavioral Activity ◽  
Glucose Content ◽  
Control Measurement ◽  
Repeated Stress

Aim. To study the effect of repeated stress on blood glucose level in rats with various behavioral characteristics and with different resistance to the development of adverse consequences of negative emotiogenic exposures. Materials and Methods. The animals were initially subjected to open field test to calculate the index of activity. Daily 4-h immobilization of rats in individual plastic cages for 8 days was used as a model of stress. Blood glucose concentration was measured with a glucometer (control measurement and on the 1st, 3rd and 8th days of repeated stress). Results. The basal level of glucose in behaviorally active (stress-resistant) rats was lower than in passive (stress-predisposed) specimens. Repeated exposure of rats to stress resulted in development of hyperglycemia. However, the dynamics of blood glucose concentration was different in specimens with different parameters of behavior. The increase in glucose concentration in active animals was most pronounced after a single exposure. By the 3rd and 8th days of stress exposures, glucose level in these rats progressively decreased (as compared to the 1st day), but remained above the basal level. Passive specimens were characterized by the increase in blood glucose concentration after a single and, particularly, after three-time restraint stress. Glucose content in these animals slightly decreased by the 8th day (as compared to the previous periods), but was above the basal level. Conclusion. The dynamics of abnormalities in carbohydrate metabolism (in particular, changes in blood glucose level) during chronic emotiogenic exposures differed in specimens with different resistance to stress factors. These data illustrate the importance of an indivi-dual approach to studying the pathophysiological mechanisms of progression and development of stress-induced disorders.

scholarly journals Lipid Profile and Blood Glucose Level of Hypertensive Population in Rural Regions of West China.

2020 ◽  
Author(s):  
Lihong Fan ◽  
Xiaojing Hu ◽  
You Li ◽  
Tiao Bai ◽  
Longfei Pan ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glucose Metabolism ◽  
Blood Glucose Level ◽  
Lipid Profile ◽  
Glucose Level ◽  
Rural Regions ◽  
Hypertensive Patients ◽  
West China ◽  
Abnormal Glucose Metabolism ◽  
Hypertensive Population

Abstract Background: In rural regions of West China, there was almost no intervention on dyslipidemias and abnormal glucose metabolism of individuals with hypertension because of no literature reporting the lipid profile or blood glucose of these patients. This study was designed to investigate the lipid profile and blood glucose level of the hypertensive population in these regions. Methods: A cross-sectional community survey was carried out in Xunyi county of Shaanxi province in West China. The study enrolled 1425 hypertensive patients. The lipid profile and blood glucose levels were assessed. Diet and physical activity were also investigated by questionnaire. Results: 54% of the population had dyslipidemias. The hypercholesterolemia (hyper-TC) and hypertriglyceridemia (hyper-TG) were the main dyslipidemias (hyper-TC:25%; hyper-TG: 33% ). The prevalence of abnormal glucose metabolism was 37%. 16% of the population had hyperglycemia. Despite of low-fat intake, the diet was unbalanced by excess salt consumption and seriously insufficient intake of vegetables, fruits and protein. Conclusion: Dyslipidemias and abnormal glucose metabolism were common in the hypertensive patients in rural areas of West China. They were needed to be invented to reduce the risks of atherosclerotic cardiovascular diseases of hypertensive patients in these regions. Unbalanced diet here may be needed to be modified.

scholarly journals Control of Blood Glucose Level for Type 1 Diabetes Mellitus using Improved Hovorka Equations: Comparison between Clinical and In-Silico Works

2020 ◽  
Author(s):  
Nur’Amanina Mohd Sohadi ◽  
Ayub Md Som ◽  
Noor Shafina Mohd Nor ◽  
Nur Farhana Mohd Yusof ◽  
Sherif Abdulbari Ali ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Blood Glucose ◽  
Blood Glucose Level ◽  
Type 1 Diabetes Mellitus ◽  
Glucose Level ◽  
In Silico ◽  
Artificial Pancreas ◽  
The Body

AbstractBackgroundType 1 diabetes mellitus (T1DM) occurs due to inability of the body to produce sufficient amount of insulin to regulate blood glucose level (BGL) at normoglycemic range between 4.0 to 7.0 mmol/L. Thus, T1DM patients require to do self-monitoring blood glucose (SMBG) via finger pricks and depend on exogenous insulin injection to maintain their BGL which is very painful and exasperating. Ongoing works on artificial pancreas device nowadays focus primarily on a computer algorithm which is programmed into the controller device. This study aims to simulate so-called improved equations from the Hovorka model using actual patients’ data through in-silico works and compare its findings with the clinical works.MethodsThe study mainly focuses on computer simulation in MATLAB using improved Hovorka equations in order to control the BGL in T1DM. The improved equations can be found in three subsystems namely; glucose, insulin and insulin action subsystems. CHO intakes were varied during breakfast, lunch and dinner times for three consecutive days. Simulated data are compared with the actual patients’ data from the clinical works.ResultsResult revealed that when the patient took 36.0g CHO during breakfast and lunch, the insulin administered was 0.1U/min in order to maintain the blood glucose level (BGL) in the safe range after meal; while during dinner time, 0.083U/min to 0.1 U/min of insulins were administered in order to regulate 45.0g CHO taken during meal. The basal insulin was also injected at 0.066U/min upon waking up time in the early morning. The BGL was able to remain at normal range after each meal during in-silico works compared to clinical works.ConclusionsThis study proved that the improved Hovorka equations via in-silico works can be employed to model the effect of meal disruptions on T1DM patients, as it demonstrated better control as compared to the clinical works.

Insulin secretion: mechanism of the stimulation by glucose

1975 ◽  
Vol 8 (1) ◽  
pp. 1-41 ◽  
Author(s):  
Erol Cerasi
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Insulin Secretion ◽  
Blood Glucose ◽  
Food Intake ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Glucose Concentration ◽  
The Central Nervous System ◽  
The Stability

Glucose is one of the substrates that is controlled with the most efficient hormonal mechanisms in higher organisms. The presence of tissues such as the central nervous system which, under normal conditions, depend solely on glucose as substrate, and the sporadic type of food intake with periods of fasting of various lengths in the mammalians necessitate that the distribution of energy-rich substrates among various tissues be continuously adjusted by changes in the secretion of a number of hormones. The efficiency of this system is evidenced by the stability of the blood glucose level in man, in whom after a carbohydrate-rich meal more than 70% of the glucose that has been ingested will be retained in the liver during a single passage of portal blood, resulting in only small changes of the glucose concentration in peripheral blood. Likewise, periods of fasting up to24–36 h are followed by modest to minimal reductions of the blood glucose level, the liver now supplying the circulation with the hexose.

An artificial pancreas provided a novel model of blood glucose level variability in beagles

2015 ◽  
Vol 18 (4) ◽  
pp. 387-390 ◽  
Author(s):  
Masaya Munekage ◽  
Tomoaki Yatabe ◽  
Hiroyuki Kitagawa ◽  
Yuka Takezaki ◽  
Takahiko Tamura ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Artificial Pancreas ◽  
Novel Model

Electrophoretically Determined Haemoglobin A1 Concentrations during Short-Term Changes in Glucose Concentration

1982 ◽  
Vol 19 (5) ◽  
pp. 350-353 ◽  
Author(s):  
Raija Puukka ◽  
Marjatta Leppilampi
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Glucose Level ◽  
Glucose Concentration ◽  
Isotonic Saline ◽  
Diabetic Patients ◽  
Intermediate Form ◽  
Electrophoretic Method

In our experience, electrophoresis on agar gel is a very satisfactory alternative to the more widely used chromatographic methods for the determination of haemoglobin A1 (HbA1). Like the chromatographic method, the electrophoretic method is unable to detect any difference between the labile intermediate form of HbA1, which changes rapidly with acute changes in blood glucose level, and the more stable end-product, which reflects long-term glucose levels. In vitro at 37°C the electrophoretically determined HbA1 concentration increases with increasing glucose concentration and with time in both normal and diabetic erythrocytes, but decreases to the preincubation concentration during further incubation of the erythrocytes in a glucose-free medium at 37°C. Similarly, if normal or diabetic erythrocytes are incubated with isotonic saline before the HbA1 assay, the labile fraction is eliminated. In diabetics, the decrease in HbA1 concentration correlates with both the blood glucose level and the preincubation HbA1 concentration. Thus for HbA1 to be an accurate indicator of long-term glucose control in diabetic patients saline incubation of the erythrocytes may be necessary before HbA1 assay by the electrophoretic method, otherwise the assay results will also reflect recent changes in the blood glucose level.

THE CRITICALLY ILL CHILD: SALICYLATE INTOXICATION

PEDIATRICS ◽  
1969 ◽  
Vol 44 (3) ◽  
pp. 440-444
Author(s):  
William E. Segar
Keyword(s):  
Blood Glucose ◽  
Blood Glucose Level ◽  
Carbohydrate Metabolism ◽  
Glucose Level ◽  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Co2 Concentration ◽  
Pharmacologic Agent ◽  
Peripheral Tissues ◽  
Salicylate Intoxication

Salicylate is a potent pharmacologic agent, and the rational therapy of salicylate intoxication must be based on an understanding of its pharmacologic actions and consequent pathophysiologic effects.l Because it acts to uncouple oxidative phosphorylation in a manner analogous to that of 2,4-dinitrophenol, salicylate is, first of all, a general metabolic stimulant.2 Oxygen consumption, carbon dioxide formation, and heat production are increased by its action; consequently, oxygen requirement, blood CO2 concentration, and the need to eliminate heat are also increased. Respiration, heart rate, and cardiac output must increase to satisfy the demands imposed by the acceleration of metabolic processes. Second, saiicylate interferes in a complex manner with the normal metabolism of carbohydrate.3 Many factors seem to be involved, some tending to decrease and others to increase the blood glucose concentralion, and, clinically, either hyperglycemia or hypoglycemia may be observed. Hyperglycemia may be partially explained by the release of epinephrmne due to activation of hypothalamic sympathetic centers. However, large doses of salicyiate also decrease aerobic metabolism and increase glucose-6-phosphatase activity, effects which tend to increase the blood glucose level. Hypoglycemia, on the other hand, may be caused by an increased utilization of glucose by peripheral tissues or by interference with gluconeogenesis by salicylates. Recent studies suggest that brain glucose concentration may be decreased despite minimal alterations in blood glucose level.4 As a result of these salicylate-mnduced alterations in carbohydrate metabolism, organic acids, particularly lactic, pyruvic, and acetoacetic, accumuiate.5 Infants appear to be particularly susceptible to the toxic effects of salicylate on carbohydrate metabolism and are more likely to have disturbances in blood glucose concentration and metabolic acidosis than are older children.

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