Generation of volatiles from heated enzymatic hydrolysates of perilla meal with coconut oil in Maillard reaction system

Perilla meal hydrolysates (PMHs) were prepared by proteases; volatile profiles from heated mixtures of PMH and coconut oil (CO) were evaluated for their application as odor providers. Amino acids composition and degree of hydrolysis, and antioxidant activity in O/W emulsion of PMHs were assessed. PMHs were heated with different concentration of CO or with CO, xylose, and cysteine, which were non-Maillard and Maillard system, respectively. Among PMHs, double enzyme treatment using Alcalase and Flavourzyme showed higher degree of hydrolysis and antioxidant activity compared to PMHs from one type of enzymes. The presence of CO significantly increased oxygen, sulfur, and nitrogen-containing volatiles from PMHs in non-Maillard system. In case of Maillard system, PMHs with 10 % (w/w) CO contributed the formation of oxygen and nitrogen-containing volatiles such as furan and 2-methylpyrazine. PMHs might serve as an odor generator in the presence of edible oils like CO.

Correction to: Effects of association colloidal structures on the oxygen solubility in oil‑in‑water emulsion matrix

[This corrects the article DOI: 10.1007/s10068-023-01338-6.].

Approaches of lipid oxidation mechanisms in oil matrices using association colloids and analysis methods for the lipid oxidation

Lipid oxidation is one of the key chemical reactions in foods containing fats and oils during production and storage. For several decades, many researchers have tried to understand the mechanisms of lipid oxidation and ways to control the rates of lipid oxidation. Theories of autoxidation or free radical chain reaction have been developed to successfully explain the phenomenon observed in oxidized lipids. Many studies have been conducted to explain the other factors that can affect the lipid oxidation such as food matrix, oxidation time and temperature, transition metal ions, pigments with sensitizing abilities, and surface-active compounds such as phospholipids, free fatty acids, monoacylglycerols, and diacylglycerols. Several strategies were developed to evaluate the degree of oxidation and oxidative stability. This review provides crucial information on the mechanism of lipid oxidation affected amphiphilic compounds and association colloids. This review article will extensively discuss about the methods for determining the oxidative stability.

Antioxidant effects and reaction volatiles from heated mixture of soy protein hydrolysates and coconut oil

Soy protein hydrolysates (SPHs) are prepared from soybean meal using commercially available protease enzymes and acid/alkali treatment. The antioxidant properties of SPHs were evaluated by measuring headspace oxygen consumption and conjugated diene formation in oil-in-water (O/W) emulsions. In addition, volatile profiles were analyzed for the heated mixture of SPHs and the coconut oil (SPHCO). Total amino acid content was the highest in double proteases. SPHs prepared from enzymes acted as better antioxidants than those prepared from acid/alkali treatments in O/W emulsions. SPHs prepared from double proteases generated the highest amounts of total volatiles and nitrogen-containing compounds in SPHCO. 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 2-methyl-butanal, benzeneacetaldehyde, and 2,6-dimethylpyrazine were the major volatiles in SPHCO. Enzymatic SPHs act as natural antioxidants in the O/W emulsion matrix, and thermal reaction products from SPHCO may contribute to the production of a unique volatile flavor in plant protein-based foods.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01189-7.

Honeybee Pollen From Southern Chile: Phenolic Profile, Antioxidant Capacity, Bioaccessibility, and Inhibition of DNA Damage

Honeybee pollen (HBP) chemical composition is highly variable conforming to the floral and geographical origin of the pollen grains. The beneficial effects and functional properties of the HBP are well-known and have been mainly attributed to their high content of antioxidant polyphenols. In this work, twelve HBPs samples from the Southern region of Chile (X Región de Los Lagos) were characterized for the first time according to their botanical origin, phenolic composition, and antioxidant activity. The in vitro gastrointestinal digestion assay was done to simulate the human upper digestive tract. Selected honeybee pollen extracts (HBPEs) were assessed as bioaccessible fractions during an in vitro gastrointestinal digestion. Contents of phenolic compounds, antioxidant capacity, and recovery index of quercetin, myricetin, and cinnamic acid were monitored in different steps of gastrointestinal digestion. Furthermore, the protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals was evaluated. The introduced species Brassica rapa L. (Brassicaceae), Lotus pedunculatus Cav. (Fabaceae), and Ulex europaeus L. (Fabaceae) predominated in all the HBPs analyzed, while the native species Buddleja globosa Hope (Scrophulariaceae), Luma apiculata (DC.) Burret (Myrtaceae), Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) and Eucryphia cordifolia Cav. (Cunoniaceae) appeared less frequently. The content of polyphenols and antioxidant capacity in HBPEs achieved full bioaccessibility at the end of the intestinal digestion step. However, results obtained by a state-of-the-art technique (i.e. HPLC-DAD) demonstrated relatively low values of bioaccessible quercetin and cinnamic acid after the digestion process. In contrast, myricetin showed a high bioaccessibility in the intestinal digestion steps. The protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals showed promising results (up to 91.2% protection). In conclusion, HBPs from the X Region de Los Lagos are rich sources of phenolic antioxidants that protect DNA from strand breakage. Therefore, the potential of HBPEs in preventing gastric and/or intestinal cancer should be further considered.

Quercetin and its ester derivatives inhibit oxidation of food, LDL and DNA

Quercetin was esterified with fatty acids (FA) in order to expand its application in a wide range of food and biological systems. The antioxidant potential of the esters were examined using hydroxyl radical scavenging activity, antioxidation in oil-in-water emulsion and bulk oil, inhibition of low-density lipoprotein (LDL) oxidation and deoxyribonucleic acid (DNA) scission. Except for oil-in-water emulsion system, quercetin derivatives demonstrated similar and/or better antioxidant activity than quercetin itself in bulk oil (quercetin with C18:1 and C22:6), hydroxyl radical scavenging assay (quercetin with C3:0-C8:0), DNA scission (quercetin with C3:0-C8:0), and LDL oxidation (quercetin with C14:0-C22:6, except C18:0). These results suggest that esterification did not compromise the antioxidant activity of the parent compound and quercetin derivatives might be useful as possible antioxidants in food and biological systems.

Ellagitannins from jabuticaba (Myrciaria jaboticaba) seeds attenuated inflammation, oxidative stress, aberrant crypt foci, and modulated gut microbiota in rats with 1,2 dimethyl hydrazine-induced colon carcinogenesis

Since dietary factors are thought to be responsible for high colon cancer risk, we investigated the chemopreventive effect of jabuticaba seed extract (LJE) by administering yogurt with or without LJE against 1,2 dimethyl hydrazine (DMH)-induced colon carcinogenesis in rats. Results showed that LJE contained a total phenolic content of 57.16 g/100 g of seed extract in which 7.67 and 10.09 g/100 g represented total flavonoids and ellagitannins, respectively. LJE protected DNA and human LDL against induced in vitro oxidation, which was associated with the ellagitannin content and with the free-radical scavenging and reducing capacities. LJE alone had a non-clastogenicity/aneugenicity property, but in combination with cisplatin, it enhanced the chromosome aberrations in cancer cells. In colon cancer-induced rats, yogurt with or without LJE caused a reduction in pro-inflammatory parameters, decreased the RNA expression of antiapoptotic cytokines and increased the expression of proapoptotic cytokines. Moreover, LJE attenuated colon cancer initiation and progression by decreasing aberrant crypt foci and LJE recovered the gut microbiome. Together, this evidence suggests that LJE provides chemopreventive protection against colon cancer development by reducing inflammation and increasing proapoptotic pathways.

Determination of soluble and insoluble-bound phenolic compounds in dehulled, whole, and hulls of green and black lentils using electrospray ionization (ESI)-MS/MS and their inhibition in DNA strand scission

The soluble and insoluble-bound phenolic fractions of hull, whole, and dehulled black and green lentil extracts were identified and quantified using electrospray ionization (ESI)-MS/MS. Several in vitro antioxidant tests and inhibition of DNA strand scission were conducted to assess different pathways of activity. The most abundant phenolics in the soluble fractions were caffeic acid (412.2 μg/g), quercetin, (486.5 μg/g) quercetin glucoside (633.6 μg/g) luteolin glucoside (239.1 μg/g) and formononetin (920 μg/g), while myricetin (534.1 μg/g) and catechin (653.4 μg/g) were the predominant phenolics in the insoluble bound fraction. Hulls of both lentil cultivars had the highest phenolic content and the strongest antioxidant activity followed by whole and dehulled samples. Thus, lentil hulls would serve as an excellent source for the production of functional foods. Moreover, ESI-MS/MS (direct infusion) analysis was the rapid and high-throughput approach for the determination of bioactives in lentils by reducing the analysis time.

Specialty seeds: Nutrients, bioactives, bioavailability, and health benefits: A comprehensive review

Seeds play important roles in human nutrition and health since ancient time. The term "specialty" has recently been applied to seeds to describe high-value and/or uncommon food products. Since then, numerous studies have been conducted to identify various classes of bioactive compounds, including polyphenols in specialty seeds. This review discusses nutrients, fat-soluble bioactives, polyphenols/bioactives, antioxidant activity, bioavailability, health benefits, and safety/toxicology of commonly consumed eight specialty seeds, namely, black cumin, chia, hemp, flax, perilla, pumpkin, quinoa, and sesame. Scientific results from the existing literature published over the last decade have been compiled and discussed. These specialty seeds, having numerous fat-soluble bioactives and polyphenols, together with their corresponding antioxidant activities, have increasingly been consumed. Hence, these specialty seeds can be considered as a valuable source of dietary supplements and functional foods due to their health-promoting bioactive components, polyphenols, and corresponding antioxidant activities. The phytochemicals from these specialty seeds demonstrate bioavailability in humans with promising health benefits. Additional long-term and well-design human intervention trials are required to ascertain the health-promoting properties of these specialty seeds.

A new analytical concept based on chemistry and toxicology for herbal extracts analysis: From phenolic composition to bioactivity

Studies regarding the bioactivity of teas are mainly based on the phenolic composition and in vitro antioxidant activity of the herbal species used in their preparation. The aim of this study was to compare the in vitro and ex vivo antioxidant activity, cytotoxic/antiproliferative activity against cancer cells, the inhibitory activity of α-amylase, α-glucosidase and angiotensin I-converting enzymes, as well as the inhibition of DNA-induced fission of the peroxyl radical, in relation to aqueous extracts of Camellia sinensis var. sinensis (CS), Ilex paraguariensis (IP), Aspalathus linearis (AL) and an optimised extract (OT) containing the three herb species. A bivariate and multivariate statistical approach was employed to associate functional activities with individual phenolic composition. The CS and OT extracts showed the highest levels of hesperidin, quercetin-3-rutinoside, (-)-epigallocatechin-3-gallate and isoquercitrin. The CS and OT extracts showed the highest antioxidant activity, greater ability to inhibit α-amylase and proliferation of HCT8 cells, and greater ability to reduce Folin-Ciocalteu reagent. The AL extract, which is the major source of quercetin-3-rutinoside, hesperidin and isoquercitrin, showed the highest ability to inhibit α-glucosidase, the inhibition of LDL oxidation and protection of human erythrocytes. The IP extract showed the highest inhibition of lipoperoxidation in brain homogenate of Wistar rats, antihypertensive activity, and A549 cell proliferation; chlorogenic acid was its major phenolic compound. In general, the in vitro functionality of each extract was dependent on its chemical composition and the OT extract presented the most varied phenolic composition, and biological activity similar to the CS sample. In conclusion, the mixture of CS, AL, and IP represents a chemical and functional-based strategy to develop functional teas.

Bioavailability and Metabolism of Food Bioactives and their Health Effects: A Review

Numerous studies have demonstrated the availability of high-quality bioactive compounds in food along with their determination and quantification techniques. Many of these identified compounds have been claimed to possess health benefits such as anti-inflammatory, anti-cancer, antioxidant, anti-allergic, anti-fungal, antimicrobial and cardioprotective spasmolytic properties. However, mere presence of these compounds does not directly correlate with their potential health effects upon consumption. Since any food consumed does not reach the blood stream in the original form and as they are broken down to various compounds it is mandatory to consider their bioavailability and metabolism that takes place upon absorption. Furthermore, the efficacy of these bioactive compounds depends on various factors including the dosage, food matrix and stability of the compound during metabolism. Various bioavailability studies indicate that the parent bioactive compound is broken into various metabolites via oxidation, dehydroxylation, de-esterification, hydrolysis, carboxylation, α- and β-oxidation processes inside the human body. Therefore, this leads to an interesting conundrum that whether the proposed health effects are due to the parent bioactive compound or due to the metabolites formed during absorption. Some details in relation to the metabolism and metabolites of food bioactives are presented in this contribution.

Preparation of Quercetin Esters and Their Antioxidant Activity

Quercetin, a polyphenolic compound, is widely distributed in plants and has numerous health benefits. However, its hydrophilicity can compromise its use in lipophilic systems. For this reason, quercetin was esterified with 12 different fatty acids as their acyl chlorides with varying chain lengths and degrees of unsaturation. Two monoesters (Q-3'-O-monoester and Q-3-O-monoester) and four diesters (Q-7,3'-O-diester, Q-3',4'-O-diester, Q-3,3'-O-diester, and Q-3,4'-O-diester) were the major products as was shown by HPLC-MS and ¹H-NMR data. The lipophilicity of quercetin derivatives was calculated; this was found to increase with fatty acid chain length. The antioxidant potential of quercetin and its derivatives was evaluated by using DPPH radical and ABTS radical cation scavenging activity; quercetin showed the highest radical scavenging activity among all tested samples. Despite the decrease of antioxidant activity in this study, the derivatives may show better antioxidant activity in lipophilic media and display improved absorption and bioavailability in the body once consumed.

Phenolic compounds in agri-food by-products, their bioavailability and health effects

Phenolic compounds constitute a large and diverse group of secondary metabolites derived from phenylalanine and tyrosine and are widely distributed throughout the plant kingdom. They could be divided into different classes such as simple phenol, phenyl acetic acid, hydroxybenzoic acid, hydroxycinnamic acid, and other phenylpropanoids as well as condensed tannins (proanthocyanidins) and hydrolysable tannins, among others, depending on their basic carbon skeleton structure. Phenolic compounds in plant-based foods have been suggested to have a number of beneficial health effects including prevention of cancer, cardiovascular disease, diabetes, immune disorders, neurogenerative disease and others. These properties are largely attributable to the antioxidant activity of the phenolic compounds as well as other mechanisms of action. Therefore, nutraceuticals of plant origin may evolve to be considered a vital aspect of dietary-disease preventive food components. Agri-food industries generate substantial quantities of phenolic rich by-products, which could serve as an attractive and commercially viable source of nutraceuticals. This contribution mainly summarizes the occurrence of phenolic compounds and some other bioactives in various Agri-food by-products, their bioavailability and health benefits.

Antioxidant activity of resveratrol ester derivatives in food and biological model systems

Resveratrol (R) was lipophilized by esterification in order to facilitate its application in a wide range of products and to possibly enhance its bioactivity. Twelve resveratrol derivatives were prepared using acyl chlorides of different chain length (C3:0-C22:6) and their antioxidant activities assessed. While resveratrol showed the highest antioxidant activity in oil-in-water emulsion, its derivatives (RC6:0, RC8:0, RC10:0, RC12:0, RC16:0) showed better antioxidant activity in a bulk oil system. Resveratrol esters RC20:5n-3 (REPA) and RC22:6n-3 (RDHA) showed the highest antioxidant activity when added to ground meat. Meanwhile, resveratrol derivatives (RC3:0-RC14:0) had better hydrogen peroxide scavenging activity than resveratrol. All test compounds except resveratrol and REPA inhibited copper-induced LDL oxidation. Moreover, test compounds effectively inhibited hydroxyl radical induced DNA scission. These results suggest that resveratrol derivatives could potentially serve as functional food ingredients and supplements for health promotion and disease risk reduction.

Lipophilization of Resveratrol and Effects on Antioxidant Activities

Resveratrol (R), a polyphenol, was structurally modified via esterification with selected fatty acids to expand its potential application in lipophilic foods, drugs, and cosmetics. The esterification was carried out using 12 different fatty acids with varying chain lengths and degrees of unsaturation (C3:0-C22:6). Two monoesters, two diesters, and one triester were identified by high-performance liquid chromatography-mass spectrometry, and the monoesters (R-3-O-monodocosahexaenoate and R-4'-O-monodocosahexaenoate) were structurally confirmed by nuclear magnetic resonance. The lipophilicity of resveratrol and its alkyl esters was calculated using ALOGPS 2.1. Resveratrol exhibited greater antioxidant activity in both 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging assays. Resveratrol esters with long-chain fatty acids (C18:0 and C18:1) showed higher antioxidant activity in the DPPH radical scavenging assay, whereas short-chain fatty acid (C3:0, C4:0, and C6:0) showed higher antioxidant activity in the ABTS radical cation scavenging assay. The results may imply that resveratrol derivatives could be used in lipophilic media as health beneficial antioxidants.

A Study on CYP2C19 and CYP2D6 Polymorphic Effects on Pharmacokinetics and Pharmacodynamics of Amitriptyline in Healthy Koreans

We performed a double-blinded, genotype-based stratification study to explore the pharmacokinetics and pharmacodynamics of amitriptyline according to CYP2C19 and CYP2D6 genotype in Korean subjects. Twenty-four healthy adults were grouped by genotype of CYP2C19 and CYP2D6. After a single dose of 25 mg of amitriptyline, blood samples were collected and anticholinergic effects were measured. The extent of N-demethylation of amitriptyline significantly decreased in subjects carrying two nonfunctional alleles of CYP2C19. The extent of hydroxylation of amitriptyline or nortriptyline was significantly reduced in subjects carrying two CYP2D6 decreased functional alleles compared with those with no or one decreased functional allele. The overall metabolic pathway of amitriptyline was more likely to be dominated by CYP2C19 than CYP2D6. The gene variations of CYP2C19 and CYP2D6 did not change the pharmacodynamic effect. The findings of this study will provide useful information on individualized drug treatment with amitriptyline considering both CYP2D6 and CYP2C19 gene variations.

Single-detector polarization-sensitive optical frequency domain imaging using high-speed intra A-line polarization modulation

We demonstrate a novel high-speed polarization-sensitive optical frequency domain imaging system employing high-speed polarization modulation. Rapid and continuous polarization modulation of light prior to illumination of the sample is accomplished by shifting the frequency of one polarization eigenstate by an amount equal to one quarter of the digitization sampling frequency. This approach enables polarization-sensitive imaging with a single detection channel and overcomes artifacts that may arise from temporal variations of the birefringence in fiber-optic imaging probes and spatial variation of birefringence in the sample.

High-speed polarization sensitive optical frequency domain imaging with frequency multiplexing

Polarization sensitive optical coherence tomography (PS-OCT) provides a cross-sectional image of birefringence in biological samples that is complementary in many applications to the standard reflectance-based image. Recent ex vivo studies have demonstrated that birefringence mapping enables the characterization of collagen and smooth muscle concentration and distribution in vascular tissues. Instruments capable of applying these measurements percutaneously in vivo may provide new insights into coronary atherosclerosis and acute myocardial infarction. We have developed a polarization sensitive optical frequency domain imaging (PS-OFDI) system that enables high-speed intravascular birefringence imaging through a fiber-optic catheter. The novel design of this system utilizes frequency multiplexing to simultaneously measure reflectance of two incident polarization states, overcoming concerns regarding temporal variations of the catheter fiber birefringence and spatial variations in the birefringence of the sample. We demonstrate circular cross-sectional birefringence imaging of a human coronary artery ex vivo through a flexible fiber-optic catheter with an A-line rate of 62 kHz and a ranging depth of 6.2 mm.

Angle-resolved optical coherence tomography with sequential angular selectivity for speckle reduction

We present a novel method for rapidly acquiring optical coherence tomography (OCT) images at multiple backscattering angles. By angularly compounding these images, high levels of speckle reduction were achieved. Signal-to-noise ratio (SNR) improvements of 3.4 dB were obtained from a homogeneous tissue phantom, which was in good agreement with the predictions of a statistical model of speckle that incorporated the optical parameters of the imaging system. In addition, the fast acquisition rate of the system (10 kHz A-line repetition rate) allowed angular compounding to be performed in vivo without significant motion artifacts. Speckle-reduced OCT images of human dermis show greatly improved delineation of tissue microstructure.

Ultrahigh-resolution full-field optical coherence microscopy using InGaAs camera

Full-field optical coherence microscopy (FFOCM) is an interferometric technique for obtaining wide-field microscopic images deep within scattering biological samples. FFOCM has primarily been implemented in the 0.8 mum wavelength range with silicon-based cameras, which may limit penetration when imaging human tissue. In this paper, we demonstrate FFOCM at the wavelength range of 0.9 - 1.4 mum, where optical penetration into tissue is presumably greater owing to decreased scattering. Our FFOCM system, comprising a broadband spatially incoherent light source, a Linnik interferometer, and an InGaAs area scan camera, provided a detection sensitivity of 86 dB for a 2 sec imaging time and an axial resolution of 1.9 mum in water. Images of phantoms, tissue samples, and Xenopus Laevis embryos were obtained using InGaAs and silicon camera FFOCM systems, demonstrating enhanced imaging penetration at longer wavelengths.

115 kHz tuning repetition rate ultrahigh-speed wavelength-swept semiconductor laser

We demonstrate an ultrahigh-speed wavelength-swept semiconductor laser using a polygon-based wavelength scanning filter. With a polygon rotational speed of 900 revolutions per second, a continuous wavelength tuning rate of 9200 nm/ms and a tuning repetition rate of 115 kHz were achieved. The wavelength tuning range of the laser was 80 nm centered at 1325 nm, and the average polarized output power was 23 mW.

Radiation treatment in patients with recurrent Kimura's disease

PURPOSE

To assess the benefits of radiotherapy for patients with recurrent Kimura's disease and to document the role of radiation treatment as a successful mode of therapy.

METHODS AND MATERIALS

From 1985 to 1991, a total of 26 patients with Kimura's disease were treated by local excision and/or systemic steroids at Yonsei University, Yonsei Cancer Center Hospital. Seventeen patients among them eventually had local recurrence after surgical excision. The 17 patients with recurrent Kimura's disease were divided into two groups on the basis of those who received radiation treatment and those who did not. Eight patients in the nonradiation group were treated by systemic steroids alone with individualized doses and schedules. The remaining nine patients in the radiation group were treated by external beam irradiation. The prescribed radiation doses varied from 21.6 to 45 Gy. A comparative analysis on treatment results between both groups was undertaken retrospectively.

RESULTS

The majority of the recurrent cases in the nonradiation group treated by steroids alone experienced rapid rerecurrence of the disease. In contrast, all of the patients except one case in the radiation group achieved excellent local control with moderate doses of radiation. There was a significant difference in the rerecurrence rate between the patients of the radiation group (11%) and the nonradiation group (75%). No clear dose-response relationship could be derived from the patients of the radiation group. No secondary malignancies in the irradiated areas have been observed.

CONCLUSION

Our results suggest that radiation treatment is preferable as an alternative option for patients with recurrent Kimura's disease who have failed to achieve local control by other modalities.

Vascular thermal adaptation in tumors and normal tissue in rats

PURPOSE

The vascular thermal adaptation in the R3230 adenocarcinoma, skin and muscle in the legs of Fischer rats was studied.

METHODS AND MATERIALS

The legs of Fischer rats bearing the R3230 AC adenocarcinoma (subcutaneously) were heated once or twice with a water bath, and the blood flow in the tumor, skin and muscle of the legs was measured with the radioactive microsphere method.

RESULTS

The blood flow in control R3230 AC tumors was 23.9 ml/100 g/min. The tumor blood flow increased about 1.5 times in 30 min and then markedly decreased upon heating at 44.5 degrees C for 90 min. In the tumors preheated 16 h earlier at 42.5 degrees C for 60 min, reheating at 44.5 degrees C increased the tumor blood flow by 2.5-fold in 30 min. Contrary to the decline in blood flow following an initial increase during the 44.5 degrees C heating without preheating, the tumor blood flow remained elevated throughout the 90 min reheating at 44.5 degrees C. These results indicated that thermal adaptation or thermotolerance developed in the tumor vasculatures after the preheating at 42.5 degrees C for 60 min. The magnitude of vascular thermal adaptation in the tumors 24 h and 48 h after the preheating, as judged from the changes in blood flow, were smaller than that 16 h after the preheating. Heating at 42.5 degrees C for 60 min induced vascular thermal adaptation also in the skin and muscle, which peaked in 48 h and 24 h, respectively, after the heating.

CONCLUSION

Heating at 42.5 degrees C for 1 h induced vascular thermal adaptation in the R3230 AC tumor, skin, and muscle of rats that peaked 16-48 h after the heating. When the tumor blood vessels were thermally adapted, the tumor blood flow increased upon heating at temperatures that would otherwise reduce the tumor blood flow. Such an increase in tumor blood flow may hinder raising the tumor temperature while it may increase tumor oxygenation.