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Ultrasound and Microwave Hyperthermia in the Treatment of Superficial Human Cancerous Tumors
Published in Leopold J. Anghileri, Jacques Robert, Hyperthermia in Cancer Treatment, 2019
C. Marchal, P. Bey, S. Hoffstetter, J. Robert
Since the beginning of clinical trials using ultrasound or microwave heating, many temperature curves have been stored on disks or on paper. From this information, we observed that between 5 to 10 min are necessary to achieve the desired thermal level, but that in a few minutes, a temperature over 40°C is still achieved. Figure 9 presents some examples of temperature evolution during treatment courses; it can be seen that the skin thermal gradient induced by the water-cooling cuff in ultrasound heating resulted in a partial cooling of the superficial part of the tumors. Microwave heating did not induce such an important inverted thermal gradient in our treatment conditions. Moreover, different comparative studies of thermal distributions induced in depth by ultrasound or microwaves on the same patient with similar applicators revealed many more inhomogeneities with ultrasound heating than with microwaves (Figure 10). These heterogeneities of thermal dose even in superficial heating could partially explain the lower clinical results obtained with ultrasound heating.
Physical technology and biological basis of hyperthermia in oncology
Published in Clifford L. K. Pang, Kaiman Lee, Hyperthermia in Oncology, 2015
Clifford L. K. Pang, Kaiman Lee
The microwave heating of tissues depends mainly on molecular friction, followed by the electrolytic effect of tissues. It has a selective heating effect on water and water-containing substances that can absorb microwaves. Microwave heating can generate heat through consumption of the electric field by the dielectric material itself, and can generate thermal effects on the living beings. The substances composed of polar molecules can soundly absorb the microwaves. The water molecule has a strong polarity, so the sweat substances can absorb microwaves. Water-rich tissues, such as muscle tissue, brain tissue, skin, and viscera, have strong absorption capacity of microwaves but penetrate shallowly, whereas tissues that lack water, such as fat and bone, absorb less heat. Cancer cells contain abundant water; therefore, microwaves are converted into heat energy after irradiation on the cancer tissue. When the cancer cell is heated to 41.4°C–43°C, the cell RNA and DNA syntheses are depressed, resulting in its death. The heat production and temperature rise under microwave effect are influenced by cancer cell electric field distribution and tissue properties. Its thermal properties and nerve–blood circulation cooling mechanism determine the temperature distribution of tissues. When hyperthermia is applied, cancer cells and normal tissues are heated to different extents. However, the blood circulation of normal tissues is faster and the heat dissipates quickly. Although the low oxygen tension of the cancer cell determines its lower pH value, sensitivity to heat, faster temperature rise, and relatively poor intratumoral blood circulation result in higher local temperature in the cancer tissue, hence it is more susceptible to thermal destruction and necrosis.
High Consumption of Monounsaturated Fat and Low Consumption of Saturated Fat
Published in John J.B. Anderson, Marilyn C. Sparling, The Mediterranean Way of Eating, 2014
John J.B. Anderson, Marilyn C. Sparling
Several kinds of olive oils exist, each with unique characteristics. All are graded in respect to their level of acidity, with lower acidity being more desirable. The best-quality olive oils are also cold-pressed, a process that does not involve the use of chemicals or heat. A list of definitions of the different types of olive oils follows: Extra-virgin olive oil (EVOO), a cold-pressed oil, comes from the first pressing of the olives and has the lowest level of acidity content (i.e., no more than 1% acid). It has a deep color, usually gold to golden green, with an intense flavor and aroma. The type of olives used also affects the color, flavor, and aroma of the oil. EVOO is usually the most expensive, but because it has such a strong flavor, only a small amount is needed to flavor foods.Virgin olive oil, also a first-pressed oil, has a higher level of acidity than EVOO, up to a maximum of 3%.Olive oil, sometimes called pure olive oil, results from a combination of refined olive oil and virgin or EVOO.Light olive oil is highly refined. The term light refers only to color and fragrance. It has about the same amount of fat (14 g) and calories (120) per tablespoon as all other olive oils and about the same amount of MFAs. During refining, however, healthful substances (e.g., some polyphenols and vitamin E) may be reduced or totally removed. Compared to unrefined oils, refined oils have a higher smoke point and so can be used in high-heat frying. EVOO and virgin olive oil are best used in cooking at low-to-medium heat, such as sautéing, and in uncooked foods, such as salad dressings and marinades, which benefit from a pronounced flavor. Microwave heating also retains more of the beneficial phenolic compounds compared to cooking with high heat.
Riboflavin immobilized Fe3O4 magnetic nanoparticles carried with n-butylidenephthalide as targeting-based anticancer agents
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Fe3O4 MNPs (∼0.1 mg) were mixed with RFMP (10−4 M, 0.2 mL) in aqueous solution containing 6 × 10−3% trifluoroacetic acid (TFA) (pH ∼3). Microwave-heating was used to facilitate sample preparation [45,46]. To accelerate the binding of RFMP onto the surface of Fe3O4 MNPs, the mixture was incubated in a microwave oven (540 W) and heated for 3 min. The resultant Fe3O4@RFMP MNPs were magnetically isolated and rinsed with aqueous solution containing 6 × 10−3% TFA (pH ∼3, 0.2 mL × 4). The supernatants containing RFMP obtained before and after microwave-heating were analyzed by fluorescence spectroscopy. The fluorescence intensity at 530 nm (λex = 450 nm) resulting from RFMP was recorded and used to estimate the binding amount of RFMP onto the surface of Fe3O4 MNPs.
Synthesis and biological evaluation of 3-arylcoumarin derivatives as potential anti-diabetic agents
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Yuheng Hu, Bing Wang, Jie Yang, Teng Liu, Jie Sun, Xiaojing Wang
The common synthetic strategies for the target compounds 3-arylcoumarin derivatives are summarised in (Scheme 2). Substituted phenylacetic acid 2a–2k were synthesised with acetophenone derivatives 1a–1k. The substituted phenylacetic acid and substituted salicylaldehyde 3a–3h were used as starting materials to obtain the corresponding compounds 4–47 by Perkin reaction. Details on the chemical and spectroscopic characterizations of compounds 4-47 were described in the Supporting Information. In order to confirm the optimal reaction conditions, 4-hydroxyphenylacetic acid 2b with 2,4-dihydroxybenzaldehyde 3a were chosen as model substrates. This paper screened different microwave power and reaction time. It was found that this reaction had the highest yield of 96% could be achieved at microwave power of 100 W reaction time of 70 min (Table 1). The previous reaction by heating in an oil bath required a reaction for 6 h, and now the reaction time was shortened to 70 min by microwave heating. Some of the crude product can be obtained by a recrystallisation purification method with a high yield (Table 2). The results showed that microwave heating method had such advantages as low cost, low-toxicity, and good commercial availability, rendering the synthetic process more environmental friendly and economical.
Submyometrial vasopressin injection before microwave ablation of vascular-rich submucosal myomas: a preliminary case study
Published in International Journal of Hyperthermia, 2019
Direct necrosis occurs at temperatures above 60 °C because most tissue proteins denature within a few seconds. In addition to direct tissue necrosis within the 60 °C isotherm, extended necrosis caused by heat conduction occurs in neighboring tissue depending on both temperature and duration when cooling by blood flow is negligible. However, vascular-rich tumors, such as hepatocellular carcinomas are resistant to microwave heating. Similar to the refrigerant cooling system of a car radiator, blood flow efficiently cools vascular-rich tissues. As an example of blood flow affecting necrotized tissue volume, microwave ablation treatment in hepatocellular carcinomas, using combined hepatic arterial embolization and temporary hepatic venous flow interruption, necrotizes significantly larger tumor volumes than those treated with hepatic arterial embolization alone [11]. Similarly, interstitial microwave irradiation cannot develop large necrotized volumes in vascular-rich myomas.