| 释义 |
insulin pump
insulin pumpn. A portable device that injects insulin at programmed intervals in order to regulate blood sugar levels in people with diabetes.EncyclopediaSeepumpinsulin pump
insulin [in´su-lin] 1. the major fuel-regulating hormone of the body, a double-chain protein formed from proinsulin in the beta cells of the islets of Langerhans in the pancreas. Insulin promotes the storage of glucose and the uptake of amino acids, increases protein and lipid synthesis, and inhibits lipolysis and gluconeogenesis. Secretion of insulin is a response of the beta cells to a stimulus; the primary stimulus is glucose, and others are amino acids and hormones such as secretin, pancreozymin, and gastrin. These chemicals play an important role in maintaining normal blood glucose levels by triggering insulin release after a meal. After insulin is released from the beta cells, it enters the blood stream and is transported to cells throughout the body. The cell membranes have insulin receptors to which the hormone becomes bonded or “fixed.” An interaction between the insulin and its receptors leads to biochemical processes that include (1) the transport of glucose, amino acids, and certain ions across the membrane and into the cell body; (2) the storage of glycogen in liver and muscle cells; (3) the synthesis of triglycerides and storage of fat; (4) the synthesis of protein, RNA, and DNA, and (5) inhibition of gluconeogenesis, degradation of glycogen and protein, and lipolysis. Although insulin increases the transport of glucose across the cell membrane of most cells, in the brain glucose enters the cells by simple diffusion through the blood--brain barrier.2. a preparation of the hormone, first discovered in 1921, used in treatment of diabetes mellitus; it may be bovine or porcine in origin (prepared from the pancreas of the animals) or a recombinant human type, although insulin of bovine origin is no longer available in the United States. Recombinant human types may duplicate exactly the human insulin protein sequence, or may be analogues with small differences in sequence. Commercially prepared insulin is available in various types that differ in the speed with which they act and in the duration of their effectiveness. There are several different types of insulin, usually classified by their onset and duration of action. (See table.)
Patients with diabetes react differently in the rate at which they absorb and utilize exogenous insulin; therefore, the duration of action varies from person to person. Moreover, the site of injection, volume of injection, and the condition of the tissues into which the insulin is injected can alter its rate of absorption and peak action times, and exercising the limb which has been injected immediately after injection can increase the speed of absorption. Insulin is measured in units.Problems of Insulin Therapy. The problem of either too much or too little insulin is always a potential hazard for the person on insulin therapy. The causes, symptoms, and treatment of hypoglycemic or insulin reaction and hyperglycemia are discussed under diabetes mellitus. Other problems of insulin therapy include insulin allergy, insulin resistance, insulin rebound due to the somogyi effect, and lipodystrophies or other localized tissue changes at injection sites.
Lipodystrophies are localized manifestations of disordered fat metabolism at the sites of insulin injection. Tissue hypertrophy can be seen as a mass of fibrous scar tissue and is sometimes called “insulin tumor.” atrophy of the tissues at the injection site appears as dimpling and pitting of the skin and underlying tissues. These problems are more common in adult females and in children. Atrophy of the tissues is relatively harmless, but hypertrophy can cause malabsorption of the insulin and a possible misdiagnosis of insulin resistance. Measures that can help prevent lipodystrophies include (1) systematic rotation of injection sites, (2) warming insulin to room temperature before injection, (3) pinching the skin when injecting the insulin so that it is deposited between fat and muscle tissue, and (4) use of human insulin.insulin allergy a hypersensitivity reaction to insulin, usually a reaction to its protein components. More purified insulins have now been developed that are less likely to cause an allergic reaction and other complications. Human insulin, prepared by recombinant genetic engineering, eliminates many problems associated with repeated insulin injections, because of reduced antibody concentrations.insulin pump a device consisting of a syringe filled with a predetermined amount of short-acting insulin, a plastic cannula and a needle, and a pump that periodically delivers the desired amount of insulin. The basal rate of insulin delivery usually is one pulse every 8 minutes, but the pump can deliver as many as 60 pulses at a time. Before each meal or snack the patient manually administers a bolus of insulin by adjusting the pump setting to the desired one-time dose. Some insulin pumps will automatically reset themselves to the basal rate of infusion after each bolus. Research is ongoing regarding implantable pumps that release insulin in response to the pump's glucose sensor. This method could potentially administer insulin in a manner resembling the normal absorption from the pancreas. Insulin pumps are worn externally and connected to an indwelling subcutaneous needle, usually inserted in the abdomen. From Black and Matassarin-Jacobs, 2001.insulin rebound extreme fluctuations in blood sugar levels owing to overreaction of the body's homeostatic feedback mechanisms for control of glucose metabolism. When exogenous insulin is given, the hypoglycemia triggers an outpouring of glucagon and epinephrine, both of which raise the blood sugar concentration markedly. Although the patient may actually have periods of hypoglycemia, urine and blood glucose tests will show hyperglycemia. Treatment is aimed at modifying the extremes by gradually lowering the insulin dosage so as to reduce stimulation of the feedback system of glucose regulation. The patient may need to take smaller doses of insulin or take it at more frequent intervals and at different times during the dayinsulin resistance impairment of the normal biologic response to insulin, which may result from abnormalities in the B-cell products, binding of insulin to antagonists such as anti-insulin antibodies, defects in or reduced numbers of receptors, and defects in the insulin action cascade in the target cell. Diabetic persons with this problem require more than 100 units daily, and some may need as much as 500 or 1000 units daily. Besides diabetes, the condition has also been associated with diseases such as obesity, acromegaly, uremia, and certain rare, possibly genetic, autoimmune diseases.insulin sensitivity test a test used to differentiate diabetes mellitus from pituitary and adrenal diabetes. A test dose of exogenous insulin will produce a rapid and marked decrease in blood glucose if the pancreas is not secreting sufficient quantities of insulin. A much less dramatic response is produced if hyperglycemia is due to excessive secretion of either pituitary or adrenocortical hormones rather than insufficient insulin production.
pump [pump] 1. an apparatus for drawing or forcing liquid or gas.2. to draw or force liquids or gases.blood pump a machine used to propel blood through the tubing of extracorporeal circulation devices.breast pump a pump for taking milk from the breast.calcium pump the mechanism of active transport of calcium (Ca2+) across a membrane, as of the sarcoplasmic reticulum of muscle cells, against a concentration gradient; the mechanism is driven by hydrolysis of ATP.enteral feeding pump an infusion pump specifically designed for administration of a solution through a tube" >feeding tube.insulin pump see insulin pump.intra-aortic balloon pump see intra-aortic balloon pump.muscle pump compression of veins by the contraction of skeletal muscles, forcing blood towards the heart against the flow of gravity; seen particularly in the deep veins of the lower limbs. Called also venous pump.Na+-K+ pump sodium-potassium pump.proton pump a system for transporting protons across cell membranes, often exchanging them for other positively charged ions.sodium pump (sodium-potassium pump) the mechanism of active transport driven by the energy generated by Na+,K+-ATPase, by which sodium (Na+) is extruded from a cell and potassium (K+) is brought in, so as to maintain the low concentration of sodium and the high concentration of potassium within the cell with respect to the surrounding medium. A high concentration of intracellular potassium is necessary for vital processes such as protein biosynthesis, certain enzyme activities, and maintenance of the membrane potential of excitable cells. Called also Na+-K+ pump.stomach pump see stomach pump.venous pump muscle pump.insulin pumpdevice used to deliver insulin subcutaenously by continuous basal infusion and intermittent bolus injections.insulin pumpn. A portable device that injects insulin at programmed intervals in order to regulate blood sugar levels in people with diabetes.insulin pump Insulin infusion device Endocrinology A device used for timed insulin delivery in DM Basic components Insulin reservoir, a pump, a power source, electronic controls, a glucose sensor; IPs are either portable or implantable. Cf Biohybrid artificial pancreas, Islet cell transplantation. in·su·lin pump (in'sŭ-lin pŭmp) Device used to deliver insulin subcutaneously by continuous basal infusion and intermittent bolus injections. INSULIN PUMPinsulin pumpA small battery-driven pump that delivers insulin subcutaneously into the abdominal wall. The pump can be programmed to deliver varying doses of insulin as a patient's need for insulin changes during the day (e.g., before exercise or meals, when physical or psychological levels of stress change). See: illustrationSee also: pump |