Ultrasound Physics
Debbie Peet, Emma Chung in Practical Medical Physics, 2021
QC tests for image quality are typically performed using a well-characterised commercially available Tissue Equivalent Test Object (TETO). This contains a series of targets embedded in an ultrasound tissue mimic. The targets and surrounding “tissue” are carefully selected to mimic the acoustic properties of soft tissue and other biological structures. The speed of sound of the tissue-mimicking material is usually 1540 m/s with impedance and attenuation similar to those of soft tissue. Different regions and objects within the phantom are used to quantify the axial, lateral and contrast resolution, maximum penetration depth, smallest cyst-like object that can be detected, tissue elasticity and calliper accuracy. The design and imaging appearance of a typical general ultrasound TETO for assessment of ultrasound image quality is shown in Figure 3.9.
Effects of Environmental Factors on the Endocrine System
George H. Gass, Harold M. Kaplan in Handbook of Endocrinology, 2020
Under specific conditions, some environmental factors may evoke toxic responses from the organism. In a recent review by Iatropoulos,31 the role of the endocrine system was emphasized in toxicological pathology. The toxic response may involve multiple endocrine malfunctions detrimental to the internal environment of the organism. The mechanism of the endocrine toxic response is often difficult to determine. One hormone may act on a wide variety of tissues, and one target tissue can be affected by several hormones. Also, the intimate relationship of the endocrine system with the neural and immune systems has further created complications in studying these toxic responses. As suggested by Iatropoulos, knowledge of comparable endocrinology across different species, biochemistry, and hormonal rhythmicity and secretion patterns is imperative. Endocrine toxicology thus encompasses broad research areas including the regulation of general energy metabolism, the maintenance of the internal environment, and the coordination of growth and reproduction. The ultimate goal is to establish the causality link between a specific toxic dose and the effect of a toxic substance with corresponding endocrine responses in most species studied including humans.
Features of Lipid Metabolism in Diabetes Mellitus and Ischemic Heart Disease
E.I. Sokolov in Obesity and Diabetes Mellitus, 2020
Numerous biochemical studies showed that the tissues most sensitive to insulin include the skeletal muscles, myocardium, adipose tissue, liver, cortical substance of the kidneys, connecting tissue, mammary glands, skin, adrenal glands, uterine, and lungs. In the central and peripheral nervous system and in the erythrocytes, insulin does not affect glucose metabolism. The degree of sensitivity of the tissues to insulin is probably determined by the activity of hexokinase or the presence of glucokinase. The tissues absolutely dependent on insulin include the myocardium, skeletal muscles, adipose tissue, liver, and island apparatus of the pancreas. In the myocardium, skeletal muscles, and adipose tissue, up to 96% of the total enzyme activity falls to the share of hexokinase II. The latter is absent or is present in miserable amounts in tissues independent of insulin. At the same time for tissues not sensitive to insulin (the brain, erythrocytes, medullary substance of the kidneys), glucose is the only energy substrate and 95% of it is oxidized by the glycolytic path or lactate with the maximum rate of transportation.
Recent advances in the combination delivery of drug for leukemia and other cancers
Published in Expert Opinion on Drug Delivery, 2020
Thikrayat Al-Attar, Sundararajan V. Madihally
When individual drugs are used, it has been recognized that higher doses are required, which carries the burden of side effects. An approach to reducing the dosage is to explore a combination of two drugs with the intent of reducing the dosage of each drug. One drug can be administrated systemically in series with local drug delivery, where cells are primed for the targeted treatment [78]. When selecting a delivery method, it is advantageous to consider the following steps: Define the target tissue/organ/cells, and have an understanding of the target microenvironment.Define the chemical and physical properties- such as molecular weight, size, charge, and hydrophilicity of the therapeutic agents.Select the required scale; nanosystems or microsystems can be selected based on medical needs, drug loading requirements, and level of release control.
Protein tyrosine phosphatase 1B (PTP1B) inhibitors as potential anti-diabetes agents: patent review (2015-2018)
Published in Expert Opinion on Therapeutic Patents, 2019
Hidayat Hussain, Ivan R Green, Ghulam Abbas, Sergazy M Adekenov, Wahid Hussain, Iftikhar Ali
Insulin is a crucial hormone which performs multiple functions to control a number of cellular activities including glucose homeostasis, protein synthesis, gene transcription, and substrate metabolism. In relation to nutrient metabolism, the main insulin targets are liver, muscle, and adipose tissue to sustain glucose homeostasis by stimulating glucose uptake in adipose skeletal muscle followed by suppressing glucose production fromthe liver. Current treatment remedies for type-2 diabetes are based on exercise and dietary management in order to enhance insulinsecretion and to improve insulin sensitivity [6]. Presently, different types of oral hypoglycemic drugs are accessible for the treatment of type-2 diabetic patients which are manily classified as (i) sulfonylureas (ii) α-glucosidase inhibitors (iii) biguanides (iv) dipeptidyl peptidase-4 (DPP-4) inhibitors, (v) GLP-1 receptor agonists (vi) amylin analogs (vii) aSGLT2 inhibitors (viii) thiazolidinediones (ix) meglitinides (x) dopamine-2 agonists, and (xi) bile acid sequestrants [2,9]. On the other hand, hypoglycemic agents exhibited a number of limitations/side effects such as weight gain, gastrointestinal complaints, headache, peripheral edema, and hypotension [2,6]. Moreover, the therapies being used currently are limited, costly and some are in fact unproductive, due to drug resistance and therefore there is an urgent need for new approaches for more potent drugs with different modes of action for the management of this life-threatning disease.
Bioactivity and mechanisms of flavonoids in decreasing insulin resistance
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Min Zhou, William H. Konigsberg, Canhua Hao, Yinbo Pan, Jie Sun, Xiaojing Wang
IR is the result of a complex combination of metabolic disorders, lipotoxicity, glucotoxicity and inflammation. The ultimate embodiment of IR lies in altered insulin signal transduction mechanisms (Figure 2). Insulin plays a role in target organs or target tissues through signal transduction, particularly liver, skeletal muscle and adipose tissue, which play unique roles in regulating human metabolism3. IR occurs when the body does not respond adequately to normal levels of insulin. IR involves multiple molecular and pathophysiological mechanisms, the cause of which may be formed through both innate and acquired factors4. Common genetic factors include mutations and polymorphisms in insulin receptors, glucose transporters and signalling proteins involved in insulin signalling. Acquired causes of IR include obesity, lack of exercise, chronic inflammation, advanced glycation end products (AGEs), excess free fatty acids (FFAs), psychological stress, smoking, alcohol consumption or certain drugs3. Flavonoids alleviate IR by acting on target proteins in the insulin signalling pathway. The biological activities of flavonoids such as anti-inflammatory, lipid-lowering and oxidative stress relief play a vital role in decreasing IR and managing metabolic syndrome (Figure 3).