Molecular characterization of a 10-kDa buckwheat molecule reactive to allergic patients' IgE.

BACKGROUND: Using the sera from buckwheat (BW)-allergic patients, several putative causative molecules were reported. However, few molecules were determined on the molecular structure. We demonstrated in 2000 that the major allergen with 24 kDa (BW24KD) is a legumin-like storage protein. OBJECTIVE: The aim of this study was to isolate and characterize further a major allergen with 10 kDa by molecular cloning. METHODS AND RESULTS: Buckwheat allergens were identified by immunoblotting analysis using sera from 14 allergic and two nonallergic individuals. We identified a protein with 10 kDa (BW10KD) that reacted with immunoglobulin E (IgE) more strongly than with IgG and IgA in 57% of the allergic patients but not with IgE in nonallergic individuals. Analyses were performed by N-terminal amino acid sequencing and molecular cloning. Physiological significance was assessed by an immunoblotting experiment showing that the reactivity of an allergic patient's serum IgE to BW10KD was competitively inhibited by natural BW extracts. CONCLUSION: Molecular cloning experiments indicated that BW10KD as a BW allergen was a member of the 2S-albumin multigene family.

p53-dependent hyperthermic enhancement of tumour growth inhibition by X-ray or carbon-ion beam irradiation.

To elucidate p53-dependency on combined treatment with radiation and hyperthermia, growth inhibition and apoptosis were analysed using transplantable human tumour. Human head and neck squamous cell carcinoma (HNSCC) cells carrying different p53 genes were transplanted into the thigh of nude mice. When the mean diameter of tumour reached 5-6 mm, the tumours were exposed to X-rays (2 Gy) or Carbon-ion (C-) beams (1 Gy) followed by heating at 42 degrees C for 20 min. Tumour growth inhibition was evaluated by measuring the diameters of tumour. The induction of apoptosis and accumulation of apoptosis-related proteins were also analysed by immunohistochemical staining. Synergistic enhancement of tumour growth inhibition by hyperthermia was observed in wild-type p53 tumours treated with X-rays or C-beams but not in mutant p53 tumours. The incidence of apoptotic cells and activated-caspase-3-positive cells after combined treatment with them were significantly high in wild-type p53 tumours compared with that in mutant p53 tumours. The hyperthermic enhancement of tumour growth inhibition by X-ray- or C-beam-irradiation was p53-dependent, suggesting that it might be highly correlated with p53-dependent apoptosis.

Changes in blood flow in locally heated intestine of rats.

Male Fischer rats were surgically castrated through a lower midline incision and a 5-8 cm long segment of small intestine was fixed to the interior of the right scrotum. Two weeks after the surgery, the herniated intestine was heated by immersing the scrotum into a water bath at different temperatures and the blood flow in the intestine was measured with the radioactive microsphere method. The blood flow in the herniated intestine increased 1.5-2.0 times when the scrotum was heated with 42.5 and 43.5 degrees C water baths for 60-90 min, but began to decrease when heated longer, although the blood flow after heating for 120 min at these temperatures was still slightly larger than the blood flow before heating. Upon heating the scrotum with 44.5 degrees C water bath, the blood flow in the herniated intestine increased to 3-fold of control by 90 min and then rapidly recessed. Massive histological damage was observed 24 h after heating with 44.5 degrees C water bath for 60 min. The blood flow in the intestine measured 1 day after 60 min heating with 43.5 degrees C and 44.5 degrees C water bath was found to be only slightly decreased. Given the relatively small decrease in blood flow, the severe damage in the intestine 24 h after heating may be attributed to direct damage to parenchymal cells.

Tumor response to neoadjuvant chemotherapy correlates with the expression of P-glycoprotein and PCNA but not GST-pi in the tumor cells of cervical carcinoma.

OBJECTIVE: To identify the clinicopathological and chemoresistant factors predicting the response to neoadjuvant chemotherapy and the patient prognosis in high-risk cervical carcinomas. METHODS: We retrospectively reviewed 47 patients with locally advanced or bulky cervical carcinoma treated with two courses of intraarterial infusion of cisplatin, doxorubicin, mitomycin C, and 5-fluorouracil (5-FU), followed by radical hysterectomy at our hospital between 1988 and 1995. Expressions of the chemoresistance-related proteins, such as P-glycoprotein, glutathione S-transferase pi (GST-pi), and proliferating cell nuclear antigen (PCNA) in the tumor cells, were examined by immunohistochemistry using pretreatment biopsy specimens. These results were compared with the chemotherapeutic response, which was evaluated by magnetic resonance imaging (MRI) and histopathology. Outcome of the patients was also studied. RESULTS: Chemotherapeutic effect of either complete (CR) or partial (PR) response on MRI was obtained in 36 of the 47 (86%) patients. Poor response to chemotherapy was significantly correlated with P-glycoprotein expression (P < 0.005) and low PCNA labeling (P < 0. 05), but not GST-pi expression in the tumor cells. Independent prognostic factors for patient survival were parametrial involvement and lymph node metastasis. Neither the expression of GST-pi nor PCNA was correlated with the patient survival. CONCLUSION: Assessment of the expression of P-glycoprotein and PCNA is potentially useful for the prediction of tumor response to neoadjuvant chemotherapy for cervical carcinomas.

Increased heating efficiency of hyperthermia using an ultrasound contrast agent: a phantom study.

It is known that there are large temperature elevations in proximity to air bubbles during US (ultrasound) heating. The existence of tiny air bubbles in the target tissue may enhance the temperature elevation in US hyperthermia. To examine this hypothesis, phantom tissue experiments using an US contrast agent consisting of tiny air bubbles surrounded by a 5% (w/v) human albumin shell (Alb) were performed. As a phantom tissue, a 2 cm cube of beef was used. The phantom tissue was heated with or without the US contrast agent by an US hyperthermia device for 3 min. The heating device was operated at 1.5 MHz with the US intensity of 0.9 W/cm2. Physiological saline solution, iodized oil, and ethanol were used for control experiments. The effect of multiple needle punctures to the beef phantom was also examined. The temperature elevation rate (TER) was defined as the ratio of temperature elevation by heating with Alb or control materials to the temperature elevation by US heating alone. The TER of Alb was 1.7, whereas the TERs of the control materials and of the multiple needle punctures were approximately 1. The administration of Alb significantly increased the temperature in US hyperthermia. In addition, the heating efficiency of Alb was compared to the effect of an increase in the US intensity. Phantom tissue was heated at various US intensities. When the US intensity was increased from 0.9 to 1.8 W/cm2, the temperature elevated by approximately 1.7-fold. Thus, the effect of the administration of Alb was almost equivalent to the effect of increase in US power intensities from 0.9 to 1.8 W/cm2 in the present experimental settings. The results suggest that the US contrast agent can be a potential enhancer in US hyperthermia.

A placebo-controlled, single-blind study to determine the appropriate alendronate dosage in postmenopausal Japanese patients with osteoporosis. The Alendronate Research Group.

Alendronate (4-amino-1-hydroxybutylidene-1,1-bisphosphonate) is a potent inhibitor of bone resorption. The efficacy and safety of 36 weeks of treatment with alendronate were evaluated in Japanese women with osteoporosis, osteoporotic osteopenia or artificial menopause. The bone mineral density (BMD) of the lumbar vertebrae, markers of bone and calcium metabolism and clinical symptoms were monitored. A total of 113 randomly selected patients with osteoporosis or osteopenia were enrolled in the study, of whom 12 were excluded from the analyses because of lack of data. As a result, 101 patients were evaluated for the safety of the drug. Since eight patients were excluded from the efficacy analysis, 93 were evaluated. The incidence of adverse effects in the placebo (P), alendronate 2.5 mg/day (L) and alendronate 10 mg/day (H) groups increased with increasing dose of alendronate, being 6.1, 14.3 and 18.2%, respectively. The most common adverse effects were gastrointestinal symptoms, none of which was serious. Lumbar BMD increased after 36 weeks of drug administration to 5.21%, 5.64% and -0.90% in the L, H and P groups, respectively (P < 0.001, L vs. P and H vs. P). Serum alkaline phosphatase activity, serum osteocalcin and urinary deoxypyridinoline excretion were significantly decreased in a dose-related manner. Serum calcium and phosphorus were also significantly decreased after alendronate administration. Serum intact PTH was transiently increased. The present results indicate that alendronate effectively decreases bone turnover in a dose-related manner and increases lumbar BMD at a dosage of 2.5 mg/day, the lowest dose used in this study, in Japanese patients with osteoporosis.

Clinical results of radiofrequency hyperthermia for malignant liver tumors.

PURPOSE: To evaluate thermometry and the clinical results of radiofrequency (RF) hyperthermia for advanced malignant liver tumors. METHODS AND MATERIALS: One hundred seventy-three patients with malignant liver tumors treated between 1983 and 1995 underwent hyperthermia. The 173 tumors consisted of 114 hepatocellular carcinomas (HCCs) and 59 non-HCCs (47 metastatic liver tumors and 12 cholangiocarcinomas). Eight-megahertz RF capacitive heating equipment was used for the hyperthermia. Two opposing 25-cm electrodes were generally used for heating the liver tumors. Our standard protocol was to administer hyperthermia 40-50 min twice a week for a total of eight sessions. The liver tumor temperature was measured by microthermocouples when possible. Transcatheter arterial embolization, radiotherapy, immunotherapy, and chemotherapy were combined with hyperthermia treatment in accordance with each patient's liver function. RESULTS: One hundred forty (81%) of the 173 patients who underwent more than four sessions of hyperthermia were evaluated in this study. Thermometry was performed in 77 (55%) of these 140 patients. The maximum tumor temperature, average tumor temperature, and minimum tumor temperature in the HCC were (mean +/- standard error) 41.2 +/- 0.2 degrees C, 40.3 +/- 1.3 degrees C, and 40.1 +/- 0.2 degrees C, respectively. The same thermometry results for non-HCC were 42.3 +/- 0.2 degrees C, 41.2 +/- 0.2 degrees C, and 40.9 +/- 0.2 degrees C, respectively. The maximum and minimum temperatures (41.8 +/- 0.2 degrees C and 40.3 +/- 0.4 degrees C) in the patients with a complete or partial response (CR or PR) were higher than those in the patients with no response or progressive disease (NR or PD) (41.3 +/- 0.5 degrees C and 39.8 +/- 0.4 degrees C), but the difference was not significant. Of the 73 cases with HCC who were evaluated by computed tomography (CT), CR was achieved in 7 (10%), PR in 15 (21%), NR in 37 (51%), and PD in 14 (19%). Of the 45 cases involving liver metastases evaluated by CT, CR was achieved in 3 (7%), PR in 17 (38%), NR in 12 (27%), and PD in 13 (29%). The 1-year cumulative survival rate for HCC patients was 30.0%, and the 5-year survival rate was 17.5%. The 1-year survival of non-HCC patients was 32.5%, and the longest survival was 30 months. The sequelae of hyperthermia included focal fat necrosis in 20 patients (12%), gastric ulceration in 4 (2%), and liver necrosis in 1 (1%). The sequelae of thermometry were severe peritoneal pain in seven patients (11%), intraperitoneal hematoma in one (1%), and pneumothorax in one (1%). CONCLUSION: Even though the thermometry results for liver tumors were not satisfactory, the treatment results are promising. Further clinical trials of RF capacitive hyperthermia for the treatment of advanced liver tumors should be encouraged.

A phase I and II clinical trial of a newly developed ultrasound hyperthermia system with an improved planar transducer.

PURPOSE: The clinical usefulness of a newly developed ultrasound hyperthermia system was evaluated. METHODS AND MATERIALS: The hyperthermia system uses a modified planer transducer operated at frequencies of 0.5, 1.0, and 1.5 MHz. The transducer has a nonvibrating part at the center to reduce the central hot spot. Frequency sweeping technique is also used to eliminate the annular hot spot around the center. Thirty-eight tumors in 29 patients were examined in this study. In 35 tumors, hyperthermia was given in conjunction with irradiation and/or chemotherapy, and in the remaining 3 tumors, hyperthermia alone was given. In all, a total of 153 hyperthermia sessions were performed. RESULTS: The number of hyperthermia sessions per tumor ranged from 1 to 7 (mean, 4.0 +/- 1.3). The number of intratumor thermometry points per session ranged from 1 to 8 (mean, 4.3 +/- 1.5). The average intratumor temperature for tumors with a maximum depth of <3 cm, 3-6 cm, and >6 cm was 42.1 +/- 1.2, 41.7 +/- 1.4, and 39.9 +/- 2.0 degrees C, respectively. The percentage of monitored intratumor points with temperature exceeding 42 degrees C was 56 +/- 31%, 43 +/- 34%, and 21 +/- 24%, respectively. Of the 30 evaluable tumors treated with combined irradiation, 12 showed complete response, 14 partial response, and 4 no change. Observed complications included pain at the treatment site in 13 of the 153 treatment sessions and vesicle formation in 3 of the 38 treatment sites. No serious complication was seen. CONCLUSIONS: These results indicate that the newly developed ultrasound hyperthermia system is clinically useful for the treatment of localized superficial and subsurface tumors with a maximum tumor depth of no more than 6 cm.

Clinical usefulness of determining the rate of thermal clearance within heated tumors.

Between June 1987 and June 1988, 28 patients (28 tumors) with liver, retroperitoneal, intrapelvic, or superficial tumors were treated with hyperthermia combined with radiotherapy and/or chemotherapy. Hyperthermia was administered once or twice a week for 30-60 min per session, up to a total of 2-11 sessions, with an 8-MHz RF capacitive heating device. Blood flow in the tumors was evaluated from the rate of thermal clearance (TCR) using the bio-heat transfer equation. The TCR was measured in the middle of the first heating session and at the end of the last heating session by turning off the output power of the heating device. For 9 patients, contrast-enhanced CT scans were taken and CT numbers at the centers of tumors were measured before and after the entire course of hyperthermia. Changes in TCR were closely related to average tumor center temperature, changes in CT number, and tumor response. When smaller and more superficial tumors were treated by hyperthermia combined with radiotherapy and/or chemotherapy that consisted of many heating sessions and during which a high average tumor center temperature was achieved, a better tumor response was obtained. The better the tumor response, the higher the local control rate became. The cause-specific survival rate of patients who achieved good tumor responses was higher than that of patients who showed poor tumor responses. Changes in TCR and CT number in heated tumors were useful and important indicators of tumor response to hyperthermia.

Targeted hyperthermia using dextran magnetite complex: a new treatment modality for liver tumors.

BACKGROUND/AIMS: Dextran magnetite complex (DM) is a colloidal suspension of subdomain magnetite particles ('magnetic fluid'). It has been reported that DM generates a great amount of heat in an AC magnetic field. MATERIAL AND METHODS: In this experimental study on Japanese white rabbits, a new treatment modality for liver tumors was examined in which the tumor is selectively heated with an intravascularly administered DM-containing embolic material followed by external application of an AC magnetic field. RESULTS: The heat generation of DM in vitro was found to be more than 3-fold greater than that with magnetite particles of 40-micron diameter. As a DM-containing embolic material, we developed a DM/Lipiodol emulsion. When DM/Lipiodol emulsion was injected into the hepatic arteries of the rabbits following VX2 tumor transplantation into the liver, embolization of the artery and selective heating of the embolized liver were successfully attained following exposure to a 100-kHz AC magnetic field of approximately 15000 A/m. Histological examination of the embolized liver disclosed that DM had accumulated in the hypervascular, viable part of the tumor. CONCLUSION: These results demonstrate the potential feasibility of using a DM-containing embolic material for targeted hyperthermia of liver tumors.

Evaluation of angiogenic inhibitors with an in vivo quantitative angiogenesis method using agarose microencapsulation and mouse hemoglobin enzyme-linked immunosorbent assay.

In the present work, using a previously reported in vivo quantitative tumor-angiogenesis model, we attempted to ascertain whether this animal model is suitable for practical use in monitoring inhibitors of tumor angiogenesis. Mouse sarcoma-180 cells, human A431 cells or rat C6 cells microencapsulated in agarose beads were implanted s.c. into C57BL/6 mice. The level of blood vessel induction at the agarose pellet site was evaluated using mouse hemoglobin enzyme-linked immunosorbent assay on day 10 after implantation. Hydrocortisone, tetrahydro-S, medroxyprogesterone acetate, pentosan polysulfate and suramin inhibited blood vessel growth in our in vivo tumor-angiogenesis assay system, and heparin enhanced the antiangiogenic effects of hydrocortisone and tetrahydro-S. These results are almost entirely consistent with those observed in common assay systems, and suggest that this method may be useful for the identification and quantitative evaluation of inhibitors of tumor angiogenesis.

Effects of calcium gluconate on the utilization of magnesium and the nephrocalcinosis in rats fed excess dietary phosphorus and calcium.

The effects of calcium gluconate on the utilization of magnesium and nephrocalcinosis in male Wistar rats made magnesium-deficient by adding excess dietary phosphorus (1.195 g of phosphorus/100 g of diet) and calcium (1.04 g of calcium/100 g of diet) were compared with the effects of calcium carbonate. The effects of dietary magnesium concentration on the magnesium status and nephrocalcinosis were also examined. Adding excess dietary phosphorus and calcium decreased the apparent magnesium absorption ratios and the concentrations of magnesium in the serum and femur and increased the deposition of calcium in the kidney, and the low magnesium condition (0.024 g of magnesium/100 g of diet) aggravated the deposition of calcium and the low magnesium status. The apparent magnesium absorption ratios and femur magnesium concentration in the rats fed a calcium gluconate diet (an equimolar mixture of calcium gluconate and calcium carbonate was used as a source of calcium) were significantly higher than in the rats fed a calcium carbonate diet (only calcium carbonate was used as a source of calcium), irrespective of dietary magnesium concentration. Dietary calcium gluconate lessened the accumulation of calcium in the kidney and increased the serum magnesium concentration compared with dietary calcium carbonate, when the rats were fed the normal magnesium diet (0.049 g of magnesium/100 g of diet) but not the low magnesium diet. We speculate that the increased utilization of magnesium by feeding the calcium gluconate diet to a limited extent prevented the low magnesium status and the severity of nephrocalcinosis caused by adding excess dietary phosphorus and calcium.

A high linoleate and a high alpha-linolenate diet induced changes in learning behavior of rats. Effects of a shift in diets and reversal of training stimuli.

Rats fed from weaning on semi-purified diets supplemented either with linoleate-rich safflower oil (S) or alpha-linolenate-rich perilla oil (P) were mated. Half of the progeny were weaned to the original diet of the dams (SS and PP), the other two groups were shifted to diets enriched in the other fatty acid (SP and PS). Brightness-discrimination learning ability was tested daily for 30 d beginning at 11 weeks of age, with a bright light as the positive stimulus. The learning performance was inferior in the group fed the safflower diet through two generations (SS) as compared with groups fed the perilla diet through two generations (PP) or for which the diets were shifted at weaning (PS and SP). The docosahexaenoate content of brain phospholipids was significantly less in the SS group compared with the three other groups. After 30 d of the learning test, the effect of shifting the stimulus was tested for another 30 d, this time using a dim light as the positive stimulus. The learning performance was superior in the PP group to the SS group throughout the latter 30 sessions, the difference being even more obvious than during the first 30 d. These results indicate that the decrease in the discrimination-learning ability induced by alpha-linolenate deficiency is a relatively reversible process; both the docosahexaenoate content in brain and the learning performance were restored by supplementing alpha-linolenate after the weaning.

[Recent progress of thermoradiotherapy in cancer therapy].

The recent progress of thermoradiotherapy for cancer is reviewed. Several biological methods for increasing the effects of heat on tumors have been developed, and some of them are being clinically investigated. Physical progress includes two new heating devices developed in Japan. One is an ultrasound heating system and the other is an intracavitary RF heating applicator in which simultaneous intracavitary irradiation is possible. The negative results of RTOG trial in USA caused a great impact in clinical hyperthermia. Careful analysis of this trial, however, demonstrated the advantages of the use of hyperthermia for those cases in which ther was good quality assurance of hyperthermia. Recent results of ESHO trials in Europe clearly demonstrated the superiority of thermoradiotherapy over radiotherapy alone for several tumors. Various site-specific clinical trials are expected to clarify the indications of thermoradiotherapy in future.

Clinical experiences in the thermoradiotherapy for advanced gastric cancer.

Recurrent and/or inoperable gastric cancer has been treated by thermoradiotherapy at Kyoto University Hospital since 1983. In the present study, the efficacy of hyperthermia (using radiofrequency capacitive heating) plus radiotherapy for gastric cancer was evaluated in 21 patients with local recurrence, abdominal wall metastases, peritonitis carcinomatosis or paraaortic node metastases. The intratumour temperature was measured using a microthermocouple thermometer. The means of the maximum, average, and minimum intratumour temperature were 43.5, 42.1, and 41.1 degrees C respectively. The local tumour response was evaluated using computed tomography (CT). The local response rate (complete regression plus partial regression/all tumours) was 88.9%, which seemed to be higher than that of other reports using thermochemotherapy or radiotherapy alone. The one-year cumulative survival rate was 39.1%.

Clinical results of thermoradiotherapy for soft tissue tumours.

Thirty-one unresectable and/or recurrent soft tissue tumours in 27 patients underwent hyperthermia in combination with radiation therapy. Locoregional hyperthermia was administered once or twice a week for 40-60 min to a total of 2-14 sessions using RF capacitive or microwave heating equipment. Radiation therapy was given 10-20 min before hyperthermia at doses of 20.8 to 70 Gy. The mean +/- SD of the maximum, average, and minimum intratumour temperatures was 44.0 +/- 2.9 degrees C, 42.3 +/- 1.6 degrees C, 40.1 +/- 1.1 degree C respectively, and that of the percentage of the intratumour points that exceeded 41 and 43 degrees C was 66.0 +/- 33.6, and 31.0 +/- 26.1 respectively. Of the 31 tumours treated, 13 (42%) showed CR (complete regression), 10 (32%) PR (> 50 and < 100% regression) and 8 (26%) NC (< 50% regression). Since intratumour low density areas on post-treatment CT scans have been demonstrated to be a useful parameter for assessing tumour response to thermoradiotherapy, the presence of low density areas was also assessed. Low density areas were classified into the following three categories according to the percent area occupied in the maximal cross-section of the tumour: type I, < 50%, type II, 50-80%; type III, > 80%. Of 20 tumours evaluable, 6 (30%) exhibited type III change, 11 (55%) type II and 3 (15%) type I. All of the type III tumours demonstrated a marked response on follow-up or histopathological examination. The major complication associated with treatment was skin ulcer in two patients. The five-year survival of the total 27 patients and 18 patients who had no distant metastases at the start of treatment was 32 and 48% respectively. These results indicate the clinical benefit of thermoradiotherapy using RF capacitive or microwave equipment for locally advanced and/or recurrent soft tissue tumours.

Effect of dietary antioxidants on the susceptibility to hepatic microsomal lipid peroxidation in the rat.

The inhibitory effect of probucol on ferrous-iron-induced microsomal lipid peroxidation was compared to that of alpha-tocopherol and butylated hydroxytoluene (BHT). Male Wistar rats were fed with diets containing 1% probucol, 0.2% BHT or 0.1% alpha-tocopherol for 30 days. There were no effects of dietary antioxidants on growth parameters, although liver weight was significantly higher in the BHT-fed rats. Probucol reduced serum levels of total and free cholesterol, while BHT feeding increased the concentrations of serum thiobarbituric-acid-reactive substances, HDL cholesterol and hepatic phospholipid. alpha-Tocopherol had no effect on these parameters. Incorporation of both, probucol and alpha-tocopherol, decreased the susceptibility of microsomes to lipid peroxidation in vitro, while BHT incorporation increased hepatic microsomal lipid peroxidation. These results suggest the possible usefulness of probucol for treatment of both hypercholesterolemia and elevated hepatic microsomal lipid peroxidation, while alpha-tocopherol decreases only an elevated lipid peroxidation. BHT works as a prooxidant.

Clinical evaluation of 430 MHz microwave hyperthermia system with lens applicator for cancer therapy.

The clinical efficacy of a microwave (MW) hyperthermia system using an electric-field converging (lens) applicator is evaluated for 42 malignant tumours with a maximum tumour depth of less than 7 cm. The mean of the maximum, average and minimum tumour temperature of the 42 tumours are 44.5, 42.5 and 40.7 C, respectively. The thermal parameters are higher for tumours in the chest, abdominal walls and hip than for those in the neck, groin and extremities. No apparent difference in thermal parameters according to the depth of tumour is shown. Of 40 tumours treated by hyperthermia in combination with radiotherapy, 20 (50%) showed complete regression, 14 (35%) showed partial regression, and six (15%) showed no change. This phase I and II study indicates clinical feasibility of the newly developed MW heating apparatus, and strongly suggests the usefulness of thermoradiotherapy in the treatment of localised superficial and subsurface malignancies.

Development of intra-arterial hyperthermia using a dextran-magnetite complex.

Dextran-magnetite complex (DM) is a colloidal sol of subdomain magnetite particles (i.e. a 'magnetic fluid'). The specific absorption rate of DM in an AC magnetic field is much higher than those of multidomain ferrite particles due to its different mechanism of heat generation. We designed two DM-containing embolic materials (a DM/Lipiodol emulsion and a DM/degradable starch microsphere suspension) to heat target tissues with the use of an external AC magnetic field. In vitro experiments showed that the heat-generating capacity of DM was not reduced in these mixtures. When these materials were injected into the renal arteries of Japanese white rabbits, they both achieved embolization of the artery and selective heating of the embolized kidney by exposure to a 100 kHz AC magnetic field of approximately 15,000 A/m. Histological examination showed a homogeneous distribution of DM in the embolized kidney. These results suggest the possibility of using DM-containing embolic materials for inductive hyperthermia.