RNase P ribozymes selected in vitro to cleave a viral mRNA effectively inhibit its expression in cell culture

An in vitro selection procedure was used to select RNase P ribozyme variants that efficiently cleaved the sequence of the mRNA encoding thymidine kinase of herpes simplex virus 1. Of the 45 selected variants sequenced, 25 ribozymes carried a common mutation at nucleotides 224 and 225 of RNase P catalytic RNA from Escherichia coli (G(224)G(225) --> AA). These selected ribozymes exhibited at least 10 times higher cleavage efficiency (k(cat)/K(m)) than that derived from the wild type ribozyme. Our results suggest that the mutated A(224)A(225) are in close proximity to the substrate and enhance substrate binding of the ribozyme. When these ribozyme variants were expressed in herpes simplex virus 1-infected cells, the levels of thymidine kinase mRNA and protein were reduced by 95-99%. Our study provides the first direct evidence that RNase P ribozyme variants isolated by the selection procedure can be used for the construction of gene-targeting ribozymes that are highly effective in tissue culture. These results demonstrate the potential for using RNase P ribozymes as gene-targeting agents against any mRNA sequences, and using the selection procedure as a general approach for the engineering of RNase P ribozymes.

Surface modification using silanated poly(ethylene glycol)s

Surface-grafted poly(ethylene glycol) (PEG) molecules are known to prevent protein adsorption to the surface. The protein-repulsive property of PEG molecules are maximized by covalent grafting. We have synthesized silanated monomethoxy-PEG (m-PEG) for covalent grafting of PEG to surfaces with oxide layers. Two different trialkoxysilylated PEGs were synthesized and characterized. The first trialkoxysilylated PEG was prepared by direct coupling of m-PEG with 3-isocyanatopropyltriethoxysilane through a urethane bond (silanated PEG I). The other silanated PEG (silanated PEG II) containing a long hydrophobic domain between PEG and a silane domain was prepared by reacting m-PEG with 1,6-diisocyanatohexane and 10-undecen-1-ol in sequence before silylation with 3-mercaptopropyl trimethoxysilane. Silanated PEGs I and II were grafted onto glass, a model surface used in our study. The PEG-grafted glass surfaces were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Although contact angle did not change much as the bulk concentration of silanated PEG used for grafting increased from 0.1 to 20 mg/ml for both PEGs I and II, the surface atomic concentrations from XPS measurements showed successful PEG grafting. Surface PEG grafting increased concentration of surface carbon but decreased silicone concentration. The high resolution C1s spectra showed higher ether carbon with lower hydrocarbon compositions for the PEG-grafted surfaces compared to the control surface. AFM images showed that more PEG molecules were grafted onto the surface as the bulk concentration used for grafting was increased. AFM images of the dried surfaces showed that the surfaces were not completely covered by PEG molecules. After hydration, however, the surface appears to be covered completely probably due to the hydration of the grafted PEG chains. Glass surfaces modified with silanated PEGs reduced fibrinogen adsorption by more than 95% as compared with the control surface. Silanated PEGs provides a simple method for PEG grafting to the surface containing oxide layers.

Treatment of superficial esophageal cancer by external radiation therapy alone: results of a multi-institutional experience

PURPOSE

To assess the effectiveness and toxicity of external radiation therapy for superficial esophageal cancer.

METHODS AND MATERIALS

During the period from March 1979 to November 1996, 78 patients with superficial esophageal cancer received radiation therapy without intracavitary irradiation at nine radiotherapy institutions in Japan. All patients had histologically-proven squamous cell carcinoma. Endoscopic ultrasonography was performed in 34 patients to discriminate mucosal from submucosal cancer. Most of the patients had received radiation therapy using conventional fractionation at an average dose of 65.5 Gy.

RESULTS

The survival rates at 1, 2, and 5 years were 88%, 73%, and 45%, respectively. The local control rates at 1, 2, and 5 years were 85%, 79%, and 66%, respectively. Although the difference was not significant, the survival rate of cancer patients with a tumor invading the submucosa was lower than that of the other patients. In 6 mucosal cancer patients, local recurrence was observed in 1 patient with extensive cancer. Regional lymph node recurrence and distant failure were not observed in mucosal cancer patients, while in 28 submucosal cancer patients, the 5-year survival rate and relapse free rate were only 49% and 43%, respectively. Univariate and multivariate analysis identified age as the only significant prognostic factor. Severe late injury, such as esophageal ulcer, perforation, and bleeding, was not observed.

CONCLUSION

External radiation therapy is effective for mucosal cancer. However, further investigation is needed to establish a better standard treatment protocol for submucosal cancer.

Surface modification with PEO-containing triblock copolymer for improved biocompatibility: in vitro and ex vivo studies

Poly(ethylene oxide) (PEO) has been frequently used to modify biomaterial surfaces for improved biocompatibility. We have used PEO-polybutadiene-PEO triblock copolymer to graft PEO to biomaterials by gamma-irradiation for a total radiation dose of 1 Mrad. The molecular weight of PEO in the block copolymer was 5000. In vitro study showed that fibrinogen adsorption to Silastic, polyethylene, and glass was reduced by 70 to approximately 95% by PEO grafting. On the other hand, the reduction of fibrinogen adsorption was only 30% on expanded polytetrafluoroethylene (e-PTFE). In vitro platelet adhesion study showed that almost no platelets could adhere to PEO-coated Silastic, polyethylene, and glass, while numerous platelet aggregates were found on the ePTFE. The platelet adhesion in vitro corresponded to the fibrinogen adsorption. When the PEO-grafted surfaces were tested ex vivo using a series shunt in a canine model, the effect of the grafted PEO was not noticeable. Platelet deposition on ePTFE was reduced by PEO grafting from 8170 +/- 1030 to 5100 +/- 460 platelets 10(-3) microm2, but numerous thrombi were still present on the PEO-grafted surface. The numbers of platelets cumulated on Silastic, polyethylene, and glass were 100 +/- 80, 169 +/- 35, and 24 +/- 22 platelets 10(-3) microm2, respectively. This is about 35% reduction in platelet deposition by PEO grafting. While the numbers of deposited platelets were small, the decreases were not as large as those expected from the in vitro study. This may be due to a number of reasons which have to be clarified in future studies, but it appears that in vitro platelet adhesion and fibrinogen adsorption studies may not be a valuable predictor for the in vivo or ex vivo behavior of the PEO-grafted surfaces.

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.

A statistical feedforward/fedback buffer control for the transmission of digital video signals compressed by DCT-based intrafield coding

A new buffer-control policy for intrafield coding of video signals is presented. This method employs two statistical bit rate predictors-feedback and feedforward. It uses a feedback predictor in stationary portions of an image sequence and a feedforward predictor at scene changes. It is shown that this buffer-control policy is reasonably simple to implement and can effectively control output bit rate even at scene changes.

Phase I/II trial of preoperative thermoradiotherapy in the treatment of urinary bladder cancer

Between April 1984 and September 1988, preoperative radiotherapy or thermoradiotherapy was administered to 49 patients with bladder cancer (T1-4N0M0; UICC classification, 1987). Twenty-one patients were preoperatively treated by radiotherapy alone, with 4 Gy per fraction and three fractions per week to a total dose of 24 Gy (TDF = 53, group 1). The other 28 patients were treated by the same radiotherapy regimen in combination with hyperthermia (group 2). Regional hyperthermia was administered for 35-60 min immediately after irradiation (two sessions per week to a total of four sessions) using an 8 MHz RF capacitive heating device. Group 2 was divided into group 2 (high), in which the average intravesical temperature (T(av)) was > 41.5 degrees C, which was the mean value, and group 2 (low) with a T(av) < 41 x 5 degrees C. Group 2 (high) showed a significantly higher incidence of down-staging and tumour degeneration than both group 1 and group 2 (low). In addition, the local recurrence rate was lower and survival time was longer in group 2 than in group 1, although not significantly so. In particular, the patients with T3-4 or grade 3 bladder cancer in group 2 had a longer average survival than those in group 1, although the difference was not significant. The toxicity associated with hyperthermia was pain during treatment, and complications were not serious.

Regional hyperthermia combined with radiotherapy in the treatment of lung cancers

Twenty locally advanced lung cancers were treated by hyperthermia in combination with radiotherapy between November 1980 and January 1990. All tumors selected had invaded or were in contact with the chest wall, so that transcutaneous insertion of thermal probes into the tumor was possible. Using an 8 or 13.56 MHZ RF capacitive heating device, hyperthermia was given once or twice a week after irradiation for 30-60 min per session (1-12 sessions in total). Radiotherapy was delivered at dose of 13.6-70 Gy. The thermal parameters analyzed were a) maximum, average, and minimum intratumor temperatures (Tmax, Tav, and Tmin), which were recorded at the termination of each treatment, and b) the percentages of the intratumor points that exceeded 41 C (%T greater than or equal to 41 C). The mean +/- SD for Tmax, Tav, Tmin, and %T greater than or equal to 41 C was 42.9 +/- 1.7 C, 41.6 +/- 1.2 C, 39.7 +/- 1.1 C, and 56.2 +/- 25.8, respectively. Larger tumors showed higher thermal parameters than the smaller tumors. Of the 12 tumors treated by definitive therapy, 2 (17%) achieved CR, 7 (58%) PR, and 3 (25%) NR. Four of 10 tumors that did not achieve CR showed large intratumor low density areas on post-treatment CT, reflecting massive coagulation necrosis. Higher thermal parameters were closely related to the appearance of low-density areas but not to changes in tumor size. Four tumors treated preoperatively were successfully resected 2 weeks after thermoradiotherapy, whereas four palliatively-treated tumors showed no regression. The side effects associated with hyperthermia were pain in 12 patients (60%) and dyspnea in 3 (15%), all of which resolved after termination of treatment. A skin abscess and a pneumothorax attributed to thermal probe insertion were observed in one patient each. These results indicate that regional RF capacitive hyperthermia is clinically feasible for local treatment of selected lung cancers.

Hyperthermia combined with radiation therapy for primarily unresectable and recurrent colorectal cancer

The value of adjuvant hyperthermia to radiotherapy in the treatment of locally advanced colorectal cancers was investigated. Between 1981 and 1989, 71 primarily unresectable or recurrent colorectal tumors were treated with radiotherapy at the Department of Radiology, Kyoto University Hospital. Of the 71 tumors, 35 were treated with radiotherapy plus hyperthermia (group I), while 36 tumors (group II) were unsuitable for hyperthermia mainly because of difficulties with the insertion of temperature probes or the thickness of the patient's subcutaneous fat (greater than 2 cm). The mean total radiation dose was 58 Gy and 57 Gy for groups I and II, respectively. Thirty deep-seated pelvic tumors were treated with an 8 MHz radiofrequency capacitive heating device, and five subsurface tumors were treated with a 430 MHz microwave hyperthermia system. Hyperthermia was given following radiotherapy for 30-60 min for a total of 2-14 sessions (mean 5.7). In 32 of the 35 tumors heated, direct measurement of tumor temperature was performed. For the five tumors treated with the microwave heating device, the means of the mean maximum, average, and minimum measured intratumoral temperatures were 45.4 degrees C, 43.3 degrees C, and 40.6 degrees C, respectively. The corresponding values were 42.2 degrees C, 41.3 degrees C, and 40.3 degrees C for the 27 tumors treated with the capacitive heating device. Effective heating of deep-seated pelvic tumors was more difficult than heating of abdominal wall or perineal tumors. The local control rate at 6 months after the treatment, which was defined as absence of local progression of the tumors, was 59% (17/29) and 37% (11/30) for groups I and II, respectively. The objective tumor response rate (complete regression plus partial response) evaluated by computed tomography was 54% (19/35) in group I, whereas it was 36% (10/28) in group II. A better response rate of 67% was obtained in the 15 tumors with a mean average tumor temperature of greater than 42 degrees C. Although limitation of our current heating devices exist, the combination of hyperthermia with radiotherapy is a promising treatment modality in the treatment of locally advanced colorectal cancer.

Radiofrequency thermotherapy for malignant liver tumors

Inoperable malignant liver tumors have been treated by radiofrequency hyperthermia at Kyoto University Hospital since 1983. In this study, clinical hyperthermia for malignant liver tumor was evaluated for 67 tumors in which we could measure intratumor temperatures. Of the 67 tumors, 41 were hepatocellular carcinomas (HCC), six cholangiocarcinomas, and 20 metastatic tumors. Cholangiocarcinoma and metastatic tumors were more susceptible to this treatment than HCC. Of the three types of HCC, higher intratumor temperatures were achieved in the diffuse type than in the nodular or massive types. The minimum tumor temperature of HCC stayed below 40 degrees C in 46% of cases, especially in larger tumors. The local response rates (complete remission plus partial remission/all) were 28% and 11% for HCC and non-HCC, respectively, for thermochemotherapy; 86% and 33%, for thermoradiotherapy; and 33% and 89%, for thermotherapy with embolization. No apparent relationship was observed between the intratumor temperatures and local response rate.

Monitoring liver tumor therapy with [18F]FDG positron emission tomography

Positron emission tomography (PET) with [18F]-2-flurodeoxy-glucose (FDG) can be utilized as a functional imaging modality for monitoring liver tumor therapy. We report three cases in which PET-FDG was more useful for this purpose than other imaging methods and tumor markers.

Clinical results of thermoradiotherapy for locally advanced and/or recurrent breast cancer--comparison of results with radiotherapy alone

From August 1979 until 1988, 26 breast cancer patients with 30 tumours were treated by hyperthermia in combination with radiotherapy. Of the 30 tumours, 11 were locally advanced primary tumours (group 1), six were locally advanced recurrent tumours after operation (group 2) and 13 were locally recurrent tumours after radiotherapy (group 3). The thermal profiles showed that the capability of an RF capacitive heating device is comparatively high for large breast tumours with a volume of more than 100 cm3, and that of a 430 MHz microwave device with a single-lens applicator is excellent for localized tumours. The response rate of group 1 and 2 tumours was excellent, and superior to that of historically controlled tumours that were treated by radiotherapy alone from July 1962 until August 1979. In group 3 the tumour response to thermoradiotherapy was not different from that to radiotherapy, but the possibility of significantly reducing total irradiation dose was indicated. More than one good heating session led to a significantly high local response, and factors having a tendency to influence local response were average minimum tumour temperature, tumour volume, and number of effective heat treatments.

Treatment of murine SCC VII tumors with localized hyperthermia and temperature-sensitive liposomes containing cisplatin

The release of cisplatin (CDDP) encapsulated in temperature-sensitive unilamellar liposomes to murine SCC VII carcinoma by localized hyperthermia and the effects of the treatment on tumor growth were studied. A transition temperature of the temperature-sensitive liposomes containing cisplatin (LIP-CDDP) was 41 degrees C. Twenty-four hours after injection of LIP-CDDP, the heated tumors (42 degrees C, 60 min) contained 3.3 times more CDDP than the unheated tumors receiving free CDDP. Although the uptake of liposome-associated CDDP by liver was approximately threefold greater at 1.5 h after injection than uptake of free CDDP, it decreased about 50% over a 24-h period. No difference in uptake of the two forms of CDDP by kidney was observed. The combination of LIP-CDDP and localized heating at 42 or 43 degrees C was more effective relative to the amount of CDDP in delaying tumor growth than that of free CDDP and hyperthermia. Treatment with LIP-CDDP plus local heating resulted in a dose-modifying factor of 5.3 when compared with free CDDP and no hyperthermia. The dose-modifying factor was 2.8 when treatment with LIP-CDDP and heat was compared with treatment with free CDDP and heat. Thus CDDP could be released selectively from the temperature-sensitive liposomes by heat and resulted in both a greater uptake of the drug and a delay in tumor growth.

Radiofrequency thermotherapy for malignant liver tumors

Inoperable malignant liver tumors have been treated by radiofrequency hyperthermia at Kyoto University Hospital since 1983. In this study, clinical hyperthermia for malignant liver tumor was evaluated for 67 tumors in which we could measure intratumor temperatures. Of the 67 tumors, 41 were hepatocellular carcinomas (HCC), six cholangiocarcinomas, and 20 metastatic tumors. Cholangiocarcinoma and metastatic tumors were more susceptible to this treatment than HCC. Of the three types of HCC, higher intratumor temperatures were achieved in the diffuse type than in the nodular or massive types. The minimum tumor temperature of HCC stayed below 40 degrees C in 46% of cases, especially in larger tumors. The local response rates (complete remission plus partial remission/all) were 28% and 11% for HCC and non-HCC, respectively, for thermochemotherapy; 86% and 33%, for thermoradiotherapy; and 33% and 89%, for thermotherapy with embolization. No apparent relationship was observed between the intratumor temperatures and local response rate.

Histopathological changes of human tumors following thermoradiotherapy

Twenty human malignant tumors treated with thermoradiotherapy were examined histopathologically. Hyperthermia was administered regionally with a 13.56-MHz or 8-MHz RF heating device, once or twice a week after irradiation, 2 to 12 sessions in total. Fifteen tumors received a total radiation dose of 26 to 70 Gy in fractions of 1.8 Gy to 2.0 Gy a day, 5 days a week, whereas five tumors received a total dose of 20 to 60 Gy in fractions of 4 Gy each, twice a week. Microscopic examination of 4 of the 20 tumors revealed complete necrosis throughout the cross-section of the entire tumor. All the four tumors had received a total dose of over 60 Gy and a tumor center temperature of over 42 degrees C. In 10 tumors, more than 50% but less than 99% of the cross-section of the entire tumor had massive coagulation necrosis. The remaining six tumors showed relatively little change; the area of intratumor necrosis was less than 50%. The grade of tumor necrosis was dependent on both the temperatures of tumor center and periphery, and a total radiation dose. The small blood vessels and capillaries in the tumor parenchyma were markedly damaged in 16 of the 20 tumors, while the blood vessels in the tumor stroma were damaged in only 2 tumors. Condensation of the destroyed nucleus observed in 15 tumors was considered to be a typical change induced by thermoradiotherapy. Viable tumor cells remained in the tumor central area in only four tumors and around the blood vessels in only three tumors. However, in the tumor peripheral area, viable tumor cells were observed in 16 out of the 20 tumors. These results indicate that histopathological changes induced by thermoradiotherapy are greater in the tumor central area than in the tumor peripheral area, and provide strong rationale for utilizing full dose radiation therapy in combination with hyperthermia as opposed to lower doses for cancer therapy.

[Clinical results of hyperthermia alone in the treatment of refractory human tumors]

Retrospective analysis of patients with refractory tumors which were treated with hyperthermia alone in five institutions was performed. Hyperthermia was applied to 30 refractory tumors including 19 deep-seated tumors for a total of 427 sessions by 8 MHz or 13.56 MHz radiofrequency capacitive heating devices. Of the 30 tumors treated, 3 (10%) showed complete regression and 2 (7%) more than 50% regression. Although tumor regression was observed in small tumors, large deep-seated tumors did not respond to heat alone. Thus, response rate of hyperthermia alone was lower than expected, although subjective improvement by hyperthermia was noted in 53% patients. We consider that hyperthermia should be combined with radiation or chemotherapy whenever possible.

Radiofrequency (RF) capacitive hyperthermia combined with radiotherapy in the treatment of abdominal and pelvic deep-seated tumors

Thermal parameters and tumor response were determined in 33 abdominal and pelvic deep-seated tumors which were treated with hyperthermia in combination with radiation therapy. Hyperthermia was applied regionally for a total of 3-14 sessions (mean; 6.4 sessions), using an 8 MHz radiofrequency (RF) capacitive heating device. An average tumor temperature (Tav) of more than 42 degrees C was achieved in 17 (52%) tumors, and intratumor temperatures above 42 degrees C could be maintained for more than 20 min (effective heat session) in 103 (52%) of the 198 heat sessions. Of the 33 tumors, 4 tumors exhibited complete regression (CR), 7 PRa (80-99% regression), 7 PRb (50-79% regression) and 15 NR (less than 50% regression). Tumor response (CR + PRa) was apparently dependent on the thermal parameters. Tumors with Tav of more than 42 degrees C or those receiving more than three effective heat sessions showed a significantly higher response rate than those heated less effectively. This trend was also noted in minimum tumor temperature. As to radiation dose, most of the responders received a total of 60-70 Gy irradiation. The two characteristic features in tumor response in effectively heated tumors, were slow tumor regression and appearance of an intratumor low density area on post-treatment computed tomography.

Histological analysis of the effect of hyperthermia on normal rabbit hepatic vasculature

The effects of hyperthermia on rabbit hepatic vasculature were studied histologically. To investigate heat-induced vascular damage in the central veins, portal veins, and hepatic arterioles, the left lobes of rabbit liver were heated locally for 30 min in the range of 40-46 degrees C. Hyperthermia was induced by an 8-MHz radiofrequency current heating device using a needle type interstitial applicator. This device allowed application of heat to a central area of 10 x 10 mm no more than 1 degree C below the preset temperature. Within the area of 1 cm2, the percentage of damaged (ruptured or thrombosed) vessels was estimated for each type of hepatic vasculature. Vascular damage following hyperthermia continued up to 24 h after heating for the three types of hepatic vasculature. Central veins were the most thermosensitive followed by portal veins, whereas hepatic arterioles were the most thermoresistant. The temperature causing 50% vascular damage 24 h after heating was 41.5-42.5 degrees C, 42.5-43.5 degrees C, and 44-45 degrees C for central veins, portal veins, and arterioles, respectively. This differential thermal responsiveness of hepatic vasculature may be attributed to the histological structure of the vessels.

Suppression of contact sensitivity by local hyperthermia treatment due to reduced Langerhans cell population in mice

The effects of local hyperthermia treatment on contact sensitivity (CS) and on the number of Langerhans cells (LCs) were studied in mice. CS was significantly suppressed when mice were sensitized in the hyperthermia treated skin I, 2 or 4 days after treatment (43 degrees C for 45 min). This suppressive effect was not observed 7 or 14 days after the treatment. CS was also suppressed when mice were sensitized in non-treated skin I day after the treatment. The density of LCs detected as ATPase-positive cells also decreased significantly 1, 2, 4 and 7 days after the treatment. There appeared to be a positive correlation between the number of LCs and the extent of CS when mice were sensitized at hyperthermia treated skin. It was observed that this suppressive effect on CS was dose- and temperature-dependent. It could be transferred by spleen cells from the hyperthermia treated and DNFB-sensitized donors, and was antigen specific when spleen cells were transferred before sensitization of the recipient mice. This indicated it was, in part, associated with the induction of suppressor cells. These findings suggest that local hyperthermia treatment reduces the number of LCs with subsequent suppression of the induction phase of delayed-type hypersensitivity by the generation of antigen-specific suppressor cells.

[Clinical results of thermoradiotherapy of locally advanced and recurrent breast cancers--comparison of results with radiotherapy alone]

From August 1979 through January 1988, 23 breast cancer patients with 25 tumors supposed to be refractory to conventional treatment were treated by thermoradiotherapy. Of the 25 tumors, 10 were locally advanced primary tumors [Group 1], 4 locally advanced recurrent tumors after operation more than 5 cm in maximum diameter [Group 2], and 11 locally recurrent tumors after radiotherapy [Group 3]. The present study was not a formal randomised-trial, but a historical-controlled study. The results were compared with tumors which were treated by radiation therapy alone between July 1962 and August 1979. The historical control groups comprised 11 tumors for Group 1, 17 for Group 2 and 19 for Group 3. Employing 4 types of heating devices (8, 13.56 MHz capacitive RF, 430, 2450 MHz microwave), hyperthermia was administered once or twice a week after irradiation, for 30-60 minutes per session, up to a total sessions of 2-9. Radiotherapy was delivered in fractions of 180 to 200 cGy per day, 5 days per week, up to 28-74.4 Gy in total, or in fraction of 400 cGy, two times per week, up to 28-60 Gy. Tumor temperatures were measured by inserting thermocouples into the tumors. The tumors that did not recur during follow-up of more than 3 months were regarded as locally controlled tumors, and the local control rate was calculated. The local control rate in Group 2 and the local response rate (CR + PRa) in Group 1 were higher than those of the historically controlled tumors. In Group 3, hyperthermia combined with lower total doses of irradiation showed a high local response rate similar to that by radiation therapy alone. Thus local hyperthermia in combination with radiation therapy seems to be more effective than radiotherapy alone for locally advanced and recurrent breast cancers.

[An evaluation of scalene lymph node metastasis in patients with gynecologic malignancies]

From 1981, through 1985, 90 patients with primary or recurrent gynecologic malignancies underwent a scalene lymph nodes (SLN) biopsy. Pelvic lymph nodes (PN) and paraaortic lymph nodes (PAN) also were examined for metastasis with CT, lymphography, and palpation or were biopsied after a laparotomy. Twenty-three of these 90 patients (25.6%) were found to have positive SLN. In 5 of these 23 (21.7%), their SLN had not been palpable on physical examination. All signs of PN, PAN and SLN were examined in 42 patients. Twenty-one of these 42 (50%) had positive PN, 14 (66.7%) had positive PAN, and 4 (28.6%) had positive SLN. Seven patients with negative PAN had no SLN metastasis. Of twenty-one patients with negative PN, 2 had positive PAN and none had an SLN metastasis. Thus, it has been concluded that an evaluation of SLN is important for the management of a gynecologic malignancy in patients with positive PAN.

Relationship between heat-induced vascular damage and thermosensitivity in four mouse tumors

The relationship between heat-induced vascular damage and thermosensitivity was studied using four mouse transplantable tumors. The tumors used were spontaneous mammary carcinoma, SCC VII carcinoma, EMT6 sarcoma, and B16 melanoma. Under cultured conditions, B16 was more thermosensitive at 43 degrees C and 44 degrees C than SCC VII or EMT6. The in vivo tumor response to heat was evaluated by the growth delay after heating at 44 degrees C for 30 min. Among the four tumors, SCC VII was the most thermosensitive in vivo followed by EMT6, whereas B16 and spontaneous mammary carcinoma were thermoresistant. Vascular damage was studied quantitatively up to 24 h after heating by using microangiography. The order of the four tumors in vascular damage was well correlated with the tumor response in vivo. Histologically, tumor vessels of spontaneous mammary carcinoma were supported by connective tissues, and those of B16 had dense endothelial cells, compared to sparse endothelial cells of SCC VII and EMT6. Our findings suggest that variability in heat sensitivity of tumors is related to variation in the histological structure of tumor vasculature. That is, tumor vasculature with perivascular connective tissues and/or dense endothelial cells is less heat labile than that composed only of sparse endothelial cells.

Microangiographic and histologic analysis of the effects of hyperthermia on murine tumor vasculature

The effects of hyperthermia on murine tumor vasculature were studied by microangiography and histological examination. The tumors used were SCC VII carcinoma and mammary adenocarcinoma of syngeneic C3H/He mice. For the quantitative analysis of microangiographic changes, the percent (%) vascular area, which was defined as the percentage of opacified tumor vessel area to the entire tumor area, was determined in each microangiogram. The % vascular area after heating in a water bath at 44 degrees C for 30 min was minimized 24 hr after heating in both types of tumors. The histologic study revealed that the initial decrease of the % vascular area was due to congestion, thrombosis, and rupture of tumor vessels, and its subsequent increase was due to angiogenesis. SCC VII was more heat sensitive than mammary adenocarcinoma in terms of tumor growth delay, and tumor vessels of SCC VII were more vulnerable to heat than those of mammary adenocarcinoma. Histological examinations showed a marked difference in the architecture of vessels between the two types of tumors. Tumor vessels of mammary adenocarcinoma were supported by a connective tissue band, whereas those of SCC VII consisted of a single endothelial cell layer. Our findings suggest that the tumor vessels supported by a connective tissue band are less sensitive to heat than those without such support. The vascular damage of SCC VII was temperature dependent, and the critical temperature at which dramatic vascular damage appeared was between 42.7 degrees C and 43.7 degrees C.

[Results of thermoradiotherapy of deep-seated tumors and problems in the evaluating its effects]

The results of thermoradiotherapy for deep-seated tumors indicated that 15% of the affected patients achieved CR and that the response rate (CR plus PR) was 58%. However, in some of the tumors which did not regress sufficiently, no regrowth was observed during follow-up. Furthermore, post-treatment CT scan revealed low-density areas occupying as much as 80% of the tumor area in 4 of 13 PRb tumors and 5 of 15 NRs. The appearance of these remarkable low-density areas on CT might be specific to thermotherapy, since it is uncommon following radiation therapy alone. Fifteen PR or NR tumors were resected and subjected to histopathological examination. It was found that cancer cells remained mainly in the tumor periphery in 12 of the 15 tumors while none were present throughout the entire tumor in the remaining 3 (2 PRbs and one NR). It was concluded from these results that it was possible to achieve local tumor control following thermoradiotherapy not only in CR tumors but also in some PRs or NRs which might remain unchanged in size but show prominent low-density areas on CT scan during follow-up. Accordingly, this suggests that the effects of thermoradiotherapy for deep-seated tumors should be evaluated on the basis of not only tumor regression but also the appearance of these low-density areas on post-treatment CT.

Radiofrequency capacitive hyperthermia for deep-seated tumors. II. Effects of thermoradiotherapy

Clinical effects and safety of radiofrequency (RF) capacitive hyperthermia in combination with radiotherapy were evaluated in 40 patients with locally advanced deep-seated tumors. Hyperthermia was administered regionally with an 8-MHz or a 13.56-MHz RF heating device, once or twice a week after irradiation, four to 13 sessions total. Radiotherapy was delivered in fractions of 170 to 200 cGy a day, 5 days a week to 30 to 70 Gy to 33 patients, whereas the remaining seven patients received a total dose of 28 to 60 Gy in fractions of 400 cGy, twice a week. Six of the 40 tumors treated showed CR (100% regression), 6 PRa (80%-100% regression), 13 PRb (50%-80% regression), and 15 NR (less than 50% regression) when assessed by tumor size on computerized tomography (CT) scan. The tumor size before treatment was significantly smaller in CR + PRa tumors than in PRb + NR ones. TDF Time-dose fractionation (TDF) and number of heat treatments, however, did not differ significantly between the both tumors. Greater regression was observed in tumors heated to 41 to 43 degrees C in the maximum temperature than in tumors heated to below 41 degrees C or above 43 degrees C. The minimum tumor temperature was not related to the tumor regression. Posttreatment CT scan revealed remarkable low-density areas in 18 of the 34 tumors that did not regress completely. Histopathologic examinations demonstrated the low-density area to be massive coagulation necrosis and no malignant cell was observed in two tumors examined thoroughly. The types of low-density areas, which were classified according to its percent area in the tumor, correlated with the maximum and minimum tumor temperature. Most of the type III tumors (more than 80% low density) did not regrow in follow-up studies. Complications consisted of subcutaneous fat necrosis in four patients, local edema in four patients, and one abdominal abscess in one patient, all of which eventually resolved. These clinical results strongly suggest the usefulness of RF capacitive hyperthermia combined with radiotherapy for the treatment of refractory deep-seated tumors, and that intratumor low-density areas which appear on posttreatment CT seems to be a good parameter for assessing the tumor response to thermoradiotherapy.

Radiofrequency capacitive hyperthermia for deep-seated tumors. I. Studies on thermometry

The thermometry results of radiofrequency (RF) capacitive hyperthermia for 60 deep-seated tumors in 59 patients are reported. Hyperthermia was administered regionally using two RF capacitive heating equipments which the authors have developed in cooperation with Yamamoto Vinyter Company Ltd., (Osaka, Japan). Intratumor temperatures were measured by thermocouples inserted through angiocatheters which were placed 5 cm to 12 cm deep into the tissues. Tumor center temperatures were measured for 307 treatments in all tumors; thermal distributions within tumors and surrounding normal tissues were obtained for 266 treatments of 53 tumors by microthermocouples. Thermometry results obtained were summarized as follows. A maximum tumor center temperature greater than 43 degrees C and 42 degrees C to 43 degrees C was obtained in 23 (38%) and 14 (23%) of the 60 tumors respectively. The time required to reach 43 degrees C in the tumor center was within 20 minutes after the start of hyperthermia in 87% of tumors heated to more than 43 degrees C. Temperature variations within a tumor exceeded 2 degrees C in 81% of tumors heated to more than 43 degrees C. The lowest tumor temperature greater than 42 degrees C was achieved in six of the 53 tumors (11%). Of 42 tumors in which temperatures of the subcutaneous fat, surrounding normal tissues, and the tumor center were compared, 24 (57%) showed the highest temperature in the tumor center and ten (24%) in the subcutaneous fat. When the heating efficacy was assessed in terms of a maximum tumor center, it great deal depended on the treatment site, tumor size, thickness of subcutaneous fat, and tumor type. Tumors in the head and neck, thorax, lower abdomen, and pelvis could be heated better than tumors in the upper abdomen. Greater heating efficacy was shown in patients with large, hypovascular tumors, and with the subcutaneous fat measuring less than 15 mm thick. The predominant limiting factor for power elevation was pain associated with heating. Systemic signs including increases in pulse rate and body temperature were not serious and seldom became limiting factors for power elevation. Our thermometry results indicate that the advantages of deep RF capacitive heating are its applicability to various anatomic sites and negligible systemic effects. The disadvantages are that its primary usefulness is limited to patients with thin subcutaneous fat and with large or hypovascular tumors.

Radiofrequency capacitive hyperthermia for deep-seated tumors. II. Effects of thermoradiotherapy

Clinical effects and safety of radiofrequency (RF) capacitive hyperthermia in combination with radiotherapy were evaluated in 40 patients with locally advanced deep-seated tumors. Hyperthermia was administered regionally with an 8-MHz or a 13.56-MHz RF heating device, once or twice a week after irradiation, four to 13 sessions total. Radiotherapy was delivered in fractions of 170 to 200 cGy a day, 5 days a week to 30 to 70 Gy to 33 patients, whereas the remaining seven patients received a total dose of 28 to 60 Gy in fractions of 400 cGy, twice a week. Six of the 40 tumors treated showed CR (100% regression), 6 PRa (80%-100% regression), 13 PRb (50%-80% regression), and 15 NR (less than 50% regression) when assessed by tumor size on computerized tomography (CT) scan. The tumor size before treatment was significantly smaller in CR + PRa tumors than in PRb + NR ones. TDF Time-dose fractionation (TDF) and number of heat treatments, however, did not differ significantly between the both tumors. Greater regression was observed in tumors heated to 41 to 43 degrees C in the maximum temperature than in tumors heated to below 41 degrees C or above 43 degrees C. The minimum tumor temperature was not related to the tumor regression. Posttreatment CT scan revealed remarkable low-density areas in 18 of the 34 tumors that did not regress completely. Histopathologic examinations demonstrated the low-density area to be massive coagulation necrosis and no malignant cell was observed in two tumors examined thoroughly. The types of low-density areas, which were classified according to its percent area in the tumor, correlated with the maximum and minimum tumor temperature. Most of the type III tumors (more than 80% low density) did not regrow in follow-up studies. Complications consisted of subcutaneous fat necrosis in four patients, local edema in four patients, and one abdominal abscess in one patient, all of which eventually resolved. These clinical results strongly suggest the usefulness of RF capacitive hyperthermia combined with radiotherapy for the treatment of refractory deep-seated tumors, and that intratumor low-density areas which appear on posttreatment CT seems to be a good parameter for assessing the tumor response to thermoradiotherapy.

Tumor response to thermoradiation therapy: use of CT in evaluation

Seventy-two tumors, mostly in deep locations, were studied retrospectively with computed tomography (CT) before and after thermoradiation therapy. Hyperthermia was administered locally or regionally with radio frequency capacitive heating equipment after irradiation (total dose, 20-70.2 Gy) for 40-60 minutes per session in a total of four to 13 sessions. Sixteen of the 72 tumors showed complete regression. Tumor regression was not related to the average maximum or minimum tumor temperature. CT scans obtained after thermoradiation therapy demonstrated a clear low-density area in 32 of 56 tumors that did not regress completely. Histopathologic examinations, performed in 14 of the 32 tumors, showed the low-density area to be massive coagulation necrosis. The low-density area was classified into three types according to its percentage area in the tumor: type 3 (more than 80%), type 2 (50%-80%), and type 1 (less than 50%). The type correlated with the average maximum and minimum tumor temperature, and follow-up observations and histopathologic examinations showed great effects in most of the type 3 tumors.

Reciprocal regulation of acetylcholinesterase and butyrylcholinesterase in mammalian skeletal muscle

Developmental regulation, from the fetal period to 11 months of age, and the influence of denervation on the appearance and disappearance of the molecular forms of acetylcholinesterase (AchE) and butyrylcholinesterase (BuchE) in rat skeletal muscle were examined. The enzyme forms were extracted from anterior tibialis in 0.01 M sodium phosphate buffer, pH 7.0, containing 1 N NaCl, 0.01 M EGTA, 1% Triton X-100, and a cocktail of antiproteases, and analyzed by velocity sedimentation on 5-20% linear sucrose gradients. Three principal forms, denoted by sedimentation coefficients of 4, 10.8, and 16 S, were observed in muscle from all age groups. The amounts of each of the molecular forms of AchE and BuchE in skeletal muscle exhibited distinct and reciprocal patterns of appearance and disappearance during pre- and postnatal development. In tissue derived from animals less than 2 weeks of age, BuchE represented the predominant component of activity in the 4 S form, was present equally with AchE in the 10.8 S form, and was subordinate to AchE in the 16 S form. Between 1 and 2 weeks of age a progressive increase in AchE activities coincident with a reduction in BuchE activities resulted in inversion in the amounts of the two enzymes present in adult muscle. Denervation of muscle caused a dramatic reduction in the presence of AchE molecular forms with no discernable influence on the presence of BuchE molecular forms. These results indicate that biosynthesis of BuchE is strictly regulated in a reciprocal manner with that of AchE, and that BuchE metabolism is independent of the state of muscle innervation. Increased synthesis of AchE and either reduced synthesis or increased degradation of BuchE can account for the reciprocal regulation of these enzymes. These characteristics of mammalian muscle contrast sharply with characteristics deduced for avian tissue (Silman et al. (1979) Nature (London) 280, 160-162). The innervation-independent metabolism of BuchE and the diverse modes of its regulation in different tissue from different species signify that BuchE function may be unrelated to cholinergic neurotransmission.

Regional hyperthermia combined with blockade of the hepatic arterial blood flow by degradable starch microspheres in pigs

The benefit of hepatic arterial microembolization by degradable starch microspheres (DSM) was investigated in regional hyperthermia of the liver. Hyperthermia with and without blood flow blockade of the hepatic artery using degradable starch microspheres was performed on six pigs. Heat was given for 30 min in each treatment by 8 MHz radiofrequency capacitive heating equipment. To maintain blood flow blockade during hyperthermia, 10 mg/kg of degradable starch microspheres was administered into the hepatic artery as an initial dose and 5 mg/kg of the drug was added periodically under the measurement of hepatic arterial blood flow by an electromagnetic flowmeter. To evaluate the effect of degradable starch microspheres, the temperature increase in the liver and rectum was compared between the treatment with and without DSM. All pigs showed a larger increase in intrahepatic temperature when heated in combination with degradable starch microspheres than without. On the other hand, temperature increase in the rectum as a result of hyperthermia to the liver was suppressed by DSM as compared with hyperthermia alone. These results indicate that hepatic arterial embolization by degradable starch microspheres potentiates radiofrequency capacitive heating of the liver. Although this study was not made with liver tumors, regional hyperthermia may be effective in the control of liver tumors when heat is given after the blockade of the hepatic artery by DSM.

[Gliomatosis peritonei]

Gliomatosis peritonei, the miliary implants of mature glial tissues on the peritoneum or omentum, is a rare complication of solid ovarian teratoma. Our case is reported and 38 previously reported cases are reviewed. The grade of the primary tumors varied from grade 0 to grade 3. Only five cases were composed entirely of mature tissues. Five of the 39 patients died. Despite of varied therapy, the rest of the patients were alive from 3 months to 38 years later. Inspite of intraperitoneal implants, the prognosis in patients with these tumors is good, irrespective of the mode of therapy. On the basis of this study, we recommended a conservative therapy for the primary tumor and therapy for the implants is not required.

Effects of step-up and step-down heating combined with radiation on murine tumor and normal tissues

Radiosensitizing effects of step-up heating (SUH) and step-down heating (SDH) on the tumor and skin were studied by using mammary adenocarcinoma transplanted to the foot of the C3H/He mouse. The tumor and skin responses were assessed by the tumor growth delay method and the skin reaction scoring method, respectively. Neither SDH (44 degrees, 10 min----42 degrees, 30 min) nor SUH (42 degrees, 30 min----44 degrees, 10 min) alone caused a substantial tumor or skin response. When the heat treatment was given immediately after irradiation, the thermal enhancement ratio (TER) was higher in SDH than in SUH for tumors as well as the skin. A therapeutic gain factor (TGF) of 1.2 was obtained in SUH, while no therapeutic benefit was found in SDH. SDH was applied at various times (0 to 3 hr) before or after irradiation. When SDH was given before irradiation, the TER was consistently high to almost the same degree for tumors and the skin regardless of the time interval, resulting in minimal or no therapeutic gain. With SDH after irradiation, the TER for the skin decreased with increase in the time interval, while the TER for the tumor was moderately enhanced. Therefore, the TGF increased with increase in the time interval and reached 2.2 when SDH was given 3 hr after radiation. SUH is slightly advantageous over SDH in terms of the TGF, and SDH should be given 3 hr after irradiation when selective tumor heating is not possible.

Effects of step-up and step-down heating on a transplantable murine tumor

The effects of step-up (42----44 degrees sequence) and step-down (44----42 degrees sequence) heating were studied on a transplantable mammary adenocarcinoma of C3H/He mouse. Tumor-bearing legs were immersed in a water bath and the response to hyperthermia was evaluated in terms of the delay in tumor growth. Tumor growth was delayed greatly with increase in the duration of treatment with 44 degrees hyperthermia, whereas with 42 degrees hyperthermia of up to 180 min, tumor growth was delayed only slightly. The effects of step-up heating were similar to those of 44 degrees hyperthermia alone and the response was enhanced by a factor of 0.9-1.1 with the 60-min treatment at 42 degrees followed by treatment at 44 degrees. Thermal resistance developed when the preheating time at 42 degrees was longer than 30 min. On the other hand, the tumor response was markedly enhanced by step-down heating by a factor of 1.8-2.4 with the treatment at 44 degrees followed by 60-min treatment at 42 degrees. Since the enhancement factor for skin damage found previously was similar to that for the tumor, therapeutic gain cannot be expected by the use of these combined heat treatments.

Histopathological changes in transplanted mouse mammary carcinoma following hyperthermia with or without radiation

The histopathological effects of hyperthermia with or without radiation were investigated in a transplanted mouse mammary carcinoma. Since the histopathological changes following hyperthermia differed greatly between the center and periphery of a tumor, we analyzed the changes in each area separately according to a semi-quantitative method developed by us. Three days after hyperthermia at 44 degrees for 45 min, undamaged tumor cells were found mostly in the tumor periphery adjacent to normal tissues. This phenomenon was observed when the entire tumor could be heated almost homogeneously. When a tumor was treated by heat alone, the thermal damage disappeared 7 days after treatment. On the other hand, treatment with hyperthermia plus radiation caused pronounced damage in the tumor center and tumor periphery 7 and 14 days after treatment. These combination effects depended on the radiation dose. The present findings demonstrate that combination of high doses of irradiation and hyperthermia is very effective for potentiating the thermal damage in the tumor periphery.

[Treatment of epithelial ovarian carcinoma with cisplatin and adriamycin: analysis of factors influencing prognosis in advanced cases]

Thirty previously untreated patients with epithelial ovarian carcinoma were treated with cisplatin and adriamycin (PA). Of eight evaluable patients, six were responders (two CRs and four PRs). The three-year survival rates were 83% for stage I, 67% for stage II, 50% for stage III, and none for stage IV. Toxicities included moderate myelo-suppression, mild nephrotoxicity, alopecia, and severe vomiting in almost all patients. Patients with residual lesions smaller than 2 cm had excellent prognosis when PA was given for more than five courses. Patients with residual lesions larger than 2 cm, however, had poor prognosis irrespective of the number of courses. No specific relation between histological grade and prognosis could be found. From the present data, aggressive cytoreductive surgery followed by PA therapy repeated more than five times is recommended for achieving a good outcome in the treatment of epithelial ovarian carcinoma.

[Clinical results of radiofrequency capacitive hyperthermia in deep-seated tumors]

The advantages of deep radiofrequency (RF) capacitive heating are its applicability to various anatomical sites and negligible systemic effects. The disadvantages are on the other hand, that its primary usefulness is limited to patients with thin subcutaneous fat and with large or hypovascular tumors. Clinical benefits of RF hyperthermia combined with radiotherapy are strongly suggested for deep-seated tumors. Intratumor low density areas on post-treatment CT and histopathological examinations are considered important parameters to assess the tumor response to thermoradiotherapy.

[Clinical evaluation of thermoradiotherapy for deep-seated tumors]

Between October 1981 and February 1985, RF capacitive heating with frequencies of 8 and 13.56 MHz was combined with radiotherapy in the treatment of 28 deep-seated tumors that were previously considered incurable by conventional radiotherapy alone. Intra-tumor temperatures of higher than 42 degrees C were achieved in 69% of overall heat sessions. Clinical evaluation was made by calculating the percentage of tumor regression from pre- and post-treatment CT films. As for the criteria of clinical evaluation, complete regression (CR) was defined as clinical disappearance of any measurable tumor, partial regression a and b (PRa and PRb) as regressions of 80% or more and 50 to less than 80%, respectively, and no response (NR) as less than 50% regression. Of 28 deep-seated tumors, 4 (14%) achieved CR, 5 (18%) PRa, 11 (39%) PRb and 8 (29%) NR. In some NR and PRb tumors, however, CT scan revealed remarkable increases in low density areas that suggested necrosis of tumor tissues. This was proved by subsequent histological examination. Clinical tumor response appeared to decrease as the initial size of the tumor increased and to be independent of any TDF factor for radiotherapy and the number of heat sessions.

Response of mammary tumors of C3H/He mice to hyperthermia and bleomycin in vivo

The cytotoxicity of bleomycin in vitro has previously been shown to be enhanced by hyperthermia. This study demonstrates in vivo a synergistic interaction between local hyperthermia (43 degrees C, 45 min) and bleomycin (15 mg/kg) against implanted mammary tumors of C3H/He mice. Hyperthermia was given by water bath heating. When combined treatments of heat and bleomycin were administered within 30 min of each other, a synergistic effect was observed. In contrast, when the interval between heat and bleomycin injection was longer than 30 min, only an additive effect was obtained. Timing is therefore considered to be a critical factor for the optimal combination of hyperthermia and bleomycin.

Clinical results of radiofrequency hyperthermia combined with radiation in the treatment of radioresistant cancers

Clinical results of radiothermotherapy applied to 40 radioresistant tumors in 36 patients were reported. Hyperthermia was administered locally using two radiofrequency (RF) capacitive heating equipment systems developed in our institution under the collaboration of Yamamoto Vinyter Co. Ltd. Hyperthermia was given twice weekly immediately after irradiation. Intratumor temperatures of 41 degrees C to 44 degrees C were maintained for 30 to 60 minutes. Radiation doses varied from 32 Gy to 60 Gy. Of the 40 tumors treated, 21 (53%) showed complete response, 16 (40%) partial response, and 3 (7%) no response when the tumor response was assessed by tumor size measurement. Of eight patients who had matched tumors treated with either radiation alone or radiation plus hyperthermia, six patients showed better response in tumors treated with radiothermotherapy than in tumors treated with radiation alone. Skin reactions following radiothermotherapy and radiation alone were comparable. The tumor response was greatly dependent on the tumor size. Greater response was observed in small tumors, although histologic examinations and long-term follow-up studies revealed an excellent effect of radiothermotherapy on the large tumors as well as on the small tumors. Tumor responses correlated with tumor center temperatures but not with histologic features. Our clinical results indicate that RF hyperthermia combined with radiation has a therapeutic benefit in the treatment of radioresistant cancers.