Machine learning-based prediction of conversion coefficients for I-123 metaiodobenzylguanidine heart-to-mediastinum ratio

PURPOSE

We developed a method of standardizing the heart-to-mediastinal ratio in 123I-labeled meta-iodobenzylguanidine (MIBG) images using a conversion coefficient derived from a dedicated phantom. This study aimed to create a machine-learning (ML) model to estimate conversion coefficients without using a phantom.

METHODS

210 Monte Carlo (MC) simulations of 123I-MIBG images to obtain conversion coefficients using collimators that differed in terms of hole diameter, septal thickness, and length. Simulated conversion coefficients and collimator parameters were prepared as training datasets, then a gradient-boosting ML was trained to estimate conversion coefficients from collimator parameters. Conversion coefficients derived by ML were compared with those that were MC simulated and experimentally derived from 613 phantom images.

RESULTS

Conversion coefficients were superior when estimated by ML compared with the classical multiple linear regression model (root mean square deviations: 0.021 and 0.059, respectively). The experimental, MC simulated, and ML-estimated conversion coefficients agreed, being, respectively, 0.54, 0.55, and 0.55 for the low-; 0.74, 0.70, and 0.72 for the low-middle; and 0.88, 0.88, and 0.88 for the medium-energy collimators.

CONCLUSIONS

The ML model estimated conversion coefficients without the need for phantom experiments. This means that conversion coefficients were comparable when estimated based on collimator parameters and on experiments.

Effects of an anesthetic mixture of medetomidine, midazolam, and butorphanol and antagonism by atipamezole in rabbits

Medetomidine (MED), midazolam (MID), and butorphanol (BUT) mixed anesthetic (MMB) has been used in laboratory animals since ketamine (KET) was designated as a narcotic in Japan in 2007. We previously reported that MMB produced anesthetic effects in mice and rats. We also demonstrated the efficacy of atipamezole (ATI), an antagonist of MED produced a quick recovery from anesthesia. Anesthetics have various anesthetic effects among different animal species. However, there is little information regarding its effects in rabbits. In the present study, we examined anesthetic effects of MMB compared to KET and xylazine mixed anesthetic (KX). We examined the antagonistic effects of ATI by intramuscular (IM) or intravenous (IV) injection in rabbits. We used the anesthetic score to measure surgical anesthetic duration and recovery time from anesthesia. During the experiments, we measured heart rate, respiratory rate, O₂-saturation, and blood pressure. We found there were no significant differences in anesthetic duration and recovery time between MMB and KX. There were no significant differences in heart rate after administration of MMB or KX. Systolic blood pressure at 10 min after administration of MMB was higher than that of KX. The antagonistic effect of ATI by IV injection worked faster than that by IM injection. Overall, MMB is a useful drug that can induce similar anesthetic effects to KX and has an antagonist of ATI that makes rabbits quickly recover from anesthesia. These results may contribute to the welfare of laboratory animals, especially rabbits.

Effects of an anesthetic mixture of medetomidine, midazolam, and butorphanol in rats-strain difference and antagonism by atipamezole

An anesthetic mixture of medetomidine (MED), midazolam (MID), and butorphanol (BUT) has been used in laboratory animals. We previously reported that this anesthetic mixture produced closely similar anesthetic effects in BALB/c and C57BL/6J strains. We also demonstrated the efficacy of atipamezole (ATI), an antagonist of MED that produced quick recovery from anesthesia in mice. Anesthetics have various anesthetic effects among animal strains. However, the differences in the effects of anesthetic mixtures in rats are unclear. In the present study, we first examined effects of the abovementioned anesthetic mixture using three different rat strains: Wistar (WST), Sprague-Dawley (SD), and Fischer 344 (F344). Second, we examined how different dosages and optimum injection timing of ATI affected recovery from anesthesia in rats. We used the anesthetic score to measure anesthetic duration and a pulse oximeter to monitor vital signs. We found no significant differences in anesthetic duration among the three different strains. However, recovery from anesthesia in the SD strain took significantly longer than in the other strains. The antagonistic effects of ATI (0.15 mg/kg and 0.75 mg/kg) were equivalent when administered at 30 min after anesthetic mixture administration. The antagonistic effects of ATI 0.75 mg/kg were stronger than those of ATI 0.15 mg/kg at 10 min after anesthetic mixture administration. This anesthetic mixture is a useful drug that can induce similar anesthetic effects in three different strains and has an antagonist, ATI, that makes rats quickly recover from anesthesia. These results may contribute to the welfare of laboratory animals.

Development and validation of a direct-comparison method for cardiac (123)I-metaiodobenzylguanidine washout rates derived from late 3-hour and 4-hour imaging

PURPOSE

The washout rate (WR) has been used in (123)I-metaiodobenzylguanidine (MIBG) imaging to evaluate cardiac sympathetic innervation. However, WR varies depending on the time between the early and late MIBG scans. Late scans are performed at either 3 or 4 hours after injection of MIBG. The aim of this study was to directly compare the WR at 3 hours (WR3h) with the WR at 4 hours (WR4h).

METHODS

We hypothesized that the cardiac count would reduce linearly between the 3-hour and 4-hour scans. A linear regression model for cardiac counts at two time-points was generated. We enrolled a total of 96 patients who underwent planar (123)I-MIBG scintigraphy early (15 min) and during the late phase at both 3 and 4 hours. Patients were randomly divided into two groups: a model-creation group (group 1) and a clinical validation group (group 2). Cardiac counts at 15 minutes (countearly), 3 hours (count3h) and 4 hours (count4h) were measured. Cardiac count4h was mathematically estimated using the linear regression model from countearly and count3h.

RESULTS

In group 1, the actual cardiac count4h/countearly was highly significantly correlated with count3h/countearly (r = 0.979). In group 2, the average estimated count4h was 92.8 ± 31.9, and there was no significant difference between this value and the actual count4h (91.9 ± 31.9). Bland-Altman analysis revealed a small bias of -0.9 with 95 % limits of agreement of -6.2 and +4.3. WR4h calculated using the estimated cardiac count4h was comparable to the actual WR4h (24.3 ± 9.6 % vs. 25.1 ± 9.7 %, p = ns). Bland-Altman analysis and the intraclass correlation coefficient showed that there was excellent agreement between the estimated and actual WR4h.

CONCLUSION

The linear regression model that we used accurately estimated cardiac count4h using countearly and count3h. Moreover, WR4h that was mathematically calculated using the estimated count4h was comparable to the actual WR4h.

Anesthetic effects of a three-drugs mixture--comparison of administrative routes and antagonistic effects of atipamezole in mice

The anesthetic mixture of medetomidine (MED), midazolam (MID) and butorphanol (BUT) produced anesthetic duration of around 40 minutes (min) in ICR mice. We reported that this anesthetic mixture produced almost the same anesthetic effects in both male and female BALB/c and C57BL/6J strains. Intraperitoneal (IP) administration of drugs has been widely used in mice. However, various injectable routes of the anesthetic mixture may cause different anesthetic effects. First, we examined effects of the anesthetic mixture by subcutaneous (SC) and intravenous (IV) injection compared to IP injection. After injection of the anesthetic mixture, administration of atipamezole (ATI) induced mice recovery from anesthesia. Secondly, we examined how different dosage and optimum injection timing of ATI affected mice recovery from anesthesia. We used an anesthetic score to measure anesthetic duration and a pulse oximeter to monitor vital signs under anesthesia. Usually, drugs from SC injection work more weakly than IP or IV injection. However, we found no significant differences of anesthetic duration among the three different injection routes. Antagonistic effects of ATI (0.3 mg/kg and 1.5 mg/kg) worked equally when administered at 30 min after injection of the anesthetic mixture. Antagonistic effects of ATI (1.5 mg/kg) were stronger than ATI (0.3 mg/kg) at 10 min after injection of the anesthetic mixture. The anesthetic mixture is a useful drug to induce nearly the same anesthetic effects by different injection routes and has an antagonist of ATI which helps mice quickly recover from anesthesia. These results may contribute to the welfare of laboratory animals.

Anesthetic effects of a mixture of medetomidine, midazolam and butorphanol in two strains of mice

The combination of ketamine and xylazine is a widely used anesthetic for laboratory animals. However, due to an abuse problem in Japan, ketamine has been specified as a narcotic since 2007. Instead of using ketamine, Kawai et al. reported an injectable formula with an equivalent effect to the mixture of ketamine and xylazine [11]. The mixture of 0.3 mg/kg body weight (b.w.) medetomidine (Med.), 4.0 mg/kg b.w. midazoram (Mid.), and 5.0 mg/kg b.w. butorphanol (But.) produced an anesthetic duration of around 40 min in outbred ICR mice. However, the anesthetic effect of the mixture for inbred mice strains remains unknown. Therefore, we examined anesthetic effects of the mixture of Med., Mid., and But. in the BALB/c and C57BL/6J strains. After intraperitoneal injection into mice, right front paw, left hind paw, and tail pinch reflexes as well as corneal and righting reflexes were observed. Every 5 min, we scored each reflex category as 0 for reaction or 1 for no reaction. As long as the total score was at least 4 out of 5, we considered the mixture as putting a mouse in a surgical anesthetic state. The mixture produced an anesthetic duration of more than 45 min in both strains of mice. These results indicate that the mixture of Med., Mid., and But. can be a useful and effective anesthesia for the BALB/c and C57BL/6J strains of inbred mice as well as outbred ICR mice.

Enhancement of morphine analgesic effect with induction of mu-opioid receptor endocytosis in rats

BACKGROUND

Morphine can desensitize mu-opioid receptor (MOR), but it does not cause internalization of the receptor after binding. Acute desensitization of MOR impairs the efficiency of signaling, whereas the receptor internalization restores the cell responsiveness to the agonists. Thereby, the property of morphine may limit the analgesic effects of this opiate drug. It has been shown that [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAMGO), a potent MOR agonist inducing the internalization, facilitates morphine to internalize MOR, suggesting that MOR agonists with low relative activity versus endocytosis (RAVE) values such as DAMGO can potentiate analgesic effects of morphine through stimulating MOR internalization. The authors examined whether the acute analgesic effect of morphine can be potentiated by low relative activity versus endocytosis agonists DAMGO and fentanyl.

METHODS

Rats injected intrathecally with opioids were subjected to a hot plate test for antinociceptive effect. Immunostained spinal dorsal horn was analyzed by confocal microscopy.

RESULTS

Fentanyl induced MOR internalization to a lesser extent than DAMGO at equianalgesic doses. Coadministration of fentanyl promoted morphine-induced MOR internalization. The analgesic effect of morphine was greatly potentiated together with decrease in the relative activity versus endocytosis value when MOR internalization was induced by coadministration of a subanalgesic dose of DAMGO or fentanyl. In contrast, the combination of DAMGO and fentanyl increased neither the analgesic effect nor the internalization of MOR.

CONCLUSIONS

The results suggest that the coadministration of morphine with MOR-internalizing agonist is clinically applicable to develop successful pain-management regimens to achieve satisfactory analgesia using less morphine.

Comparative Somatic and Visceral Antinociception and Neurotoxicity of Intrathecal Bupivacaine, Levobupivacaine, and Dextrobupivacaine in Rats

Background

The current study investigated whether racemic bupivacaine and its S(-)- and R(+)-enantiomers, levobupivacaine and dextrobupivacaine, differ in somatic and visceral antinociception and neurotoxicity when administered intrathecally in rats.

Methods

In experiment 1, rats intrathecally received 15 microl saline or 0.125, 0.25, 0.5, or 1% bupivacaine, levobupivacaine, or dextrobupivacaine. The tail-flick and colorectal distension tests were performed to assess somatic and visceral antinociceptive effects, respectively, for 180 min after injection. In experiment 2, rats given 0.25% anesthetic solutions were evaluated with colorectal distension-induced response in blood pressure and heart rate. In experiment 3, four groups of rats received a 1-h infusion of saline or 2.5% bupivacaine, levobupivacaine, or dextrobupivacaine. Additional rats received either 1.25% bupivacaine or levobupivacaine for 1 h. Four days after infusion, animals were assessed for persistent sensory impairment using the tail-flick test. Spinal cords and nerve roots were obtained for histologic analysis.

Results

In experiment 1, the three drugs produced similar time course effects and dose-effect relations in tail-flick latency. Colorectal distension thresholds and motor paralysis were slightly lower and less apparent, respectively, at some concentrations in rats given levobupivacaine than in those given the other agents. In experiment 2, colorectal distension-induced response in heart rate was less depressed in rats given levobupivacaine than in those given the other anesthetics. In experiment 3, three groups of rats given 2.5% anesthetic solutions developed similar significant increases in tail-flick latency and incurred similar morphologic damage. Two groups of rats receiving 1.25% anesthetic solutions were similar in functional impairment and nerve injury scores.

Conclusions

The results suggest that, when administered intrathecally in rats, bupivacaine and its R(+)- and S(-)-enantiomers are similar for somatic antinociception and neurotoxicity but slightly different in visceral antinociception and motor paralysis, in which levobupivacaine is less potent than the others.

The Comparative Neurotoxicity of Intrathecal Lidocaine and Bupivacaine in Rats

There is a considerable difference in the number of reports of neurologic injury in the literature between lidocaine and other local anesthetics. Few in vivo animal studies have produced convincing results showing a difference in neurotoxicity among anesthetics. We investigated whether lidocaine and bupivacaine differ with respect to sensory impairment and histologic damage when equipotent doses of the two are administered intrathecally in rats. First, to determine relative anesthetic potency, rats intrathecally received 20 muL of saline, 0.625%, 1.25%, 2.5%, or 5% lidocaine, or 0.125%, 0.25%, 0.5%, or 1.0% bupivacaine, and were examined with the tail-flick test for 90 min. The potency ratio calculated was approximately 1:4.70 (95% confidence interval, 3.65-6.07) for lidocaine/bupivacaine. In the next experiment, 45 rats intrathecally received 20 muL of saline, 2.13% bupivacaine (approximately 1.5 mg/kg), or 10% lidocaine (approximately 6.9 mg/kg), and were examined for persistent functional impairment and morphologic damage. Rats given lidocaine developed significantly more prolonged tail-flick latencies than those in other groups 4 days after injection and incurred more morphologic damage than those given saline or bupivacaine. In conclusion, although the doses of anesthetics administered were larger than those used clinically, the present results suggest that bupivacaine is less neurotoxic than lidocaine when administered intrathecally at equipotent concentrations in the rat model.

IMPLICATIONS

Bupivacaine induces less severe functional impairment and morphologic damage than lidocaine when the two anesthetics are intrathecally administered at equipotent concentrations in the rat.

The interaction between gamma-aminobutyric acid agonists and diltiazem in visceral antinociception in rats

To examine whether the gamma-aminobutyric acid (GABA) receptor agonists and L-type voltage-dependent calcium channel blockers potentiate each other on the visceral antinociceptive effects at the spinal cord, we assessed visceral nociception with colorectal distension (CD) test in rats with an intrathecal catheter. The measurements were performed after intrathecal administration of a GABA agonist (muscimol or baclofen), a calcium channel blocker (diltiazem), or the combination of the two. CD threshold did not change after muscimol 0.1 microg, baclofen 0.01 microg, or diltiazem 100 microg, but increased slightly after muscimol 1 microg and baclofen 0.1 microg. When muscimol 0.1 microg or 1 microg was administered with diltiazem, the increase in CD threshold was significantly larger than muscimol alone (at 5 min, 26.2% versus 0.6% MPE (maximum possible effect) or 84.5% versus 19.5%MPE, respectively; P < 0.01). The CD threshold after the combination of baclofen 0.1 microg and diltiazem also showed a significantly larger increase than that seen after baclofen alone (at 5 min, 48.0% versus 14.3% MPE; P < 0.01). Motor paralysis observed with muscimol 1 microg did not increase when muscimol was coadministered with diltiazem. In conclusion, intrathecal diltiazem in combination with a GABA agonist, muscimol or baclofen, potentiated the GABA agonists-induced visceral antinociception without increasing motor paralysis.

IMPLICATIONS

Intrathecal administration of diltiazem in combination with a gamma-aminobutyric acid (GABA) agonist, muscimol or baclofen, potentiated the GABA agonists-induced visceral antinociception but did not affect motor paralysis. The present results indicate that the coadministration of the two types of drugs may be clinically useful.

Comparative Neurotoxicity of Intrathecal and Epidural Lidocaine in Rats

Background

Although there is a considerable difference in the number of clinical reports of neurologic injury between spinal anesthesia and other regional techniques, there are no animal data concerning a difference in the local anesthetic neurotoxicity between intrathecal and epidural administration. In the current study, the functional and morphologic effects of lidocaine administered intrathecally and epidurally were compared in rats.

Methods

Male rats were implanted with an intrathecal or epidural catheter through L4-L5 vertebra in the caudal direction. In experiment 1, to determine relative anesthetic potency, 16 rats received repetitive injections of 2.5% lidocaine into intrathecal or epidural space in different volumes and were examined for tail flick test for 90 min. In experiment 2, to ascertain whether the relative potency obtained in experiment 1 would apply to other concentrations of lidocaine, additional rats received saline, 1%, 2.5%, or 5% lidocaine in a volume of 20 or 100 microl through the intrathecal or epidural catheter, respectively. In experiment 3, additional rats that received saline, 2.5% lidocaine, or 10% lidocaine in a volume of 20 or 100 microl through the intrathecal or epidural catheter, respectively, were examined for persistent functional impairment and morphologic damage.

Results

In experiment 1, the two techniques produced parallel dose-effect curves that significantly differed from each other. The potency ratio calculated was approximately 4.72 (3.65-6.07):1 for intrathecal:epidural lidocaine. In experiment 2, every lidocaine solution produced a similar increase in tail flick latency for the two techniques. In experiment 3, five of eight rats given 10% intrathecal lidocaine incurred functional impairment 4 days after injection, whereas no rats in the other groups did. Significantly more morphologic damage was observed in rats given 10% intrathecal lidocaine than in those given 10% epidural lidocaine.

Conclusions

Persistent functional impairment occurred only after intrathecal lidocaine. Histologic damage in the nerve roots and the spinal cord was less severe after epidural lidocaine than after intrathecal lidocaine. The current results substantiate the clinical impression that neurologic complications are less frequent after epidural anesthesia than after spinal anesthesia.

Spinal coadministration of ketamine reduces the development of tolerance to visceral as well as somatic antinociception during spinal morphine infusion

This study was designed to investigate the effects of ketamine, an N-methyl-D-aspartate receptor antagonist, on the development of tolerance to morphine and morphine antinociception during intrathecal infusion. Two intrathecal catheters were implanted in the subarachnoid space in male rats under pentobarbital anesthesia. One catheter was used for the intrathecal infusion with the following solutions: morphine 1 microg x kg(-1) x hr(-1)(M1) and 5 microg x kg(-1) x hr(-1) (M5);ketamine 250 microg x kg(-1) x hr(-1) (K250); morphine plus ketamine, 1 microg x kg(-1) x hr(-1) plus 250 microg x kg(-1) x hr(-1) (M1 + K250) and 5 microg x kg(-1) x hr(-1) + 250 microg x kg(-1) x hr(-1) (M5 + K250); or saline. The other catheter was used for morphine challenge tests. The responses to noxious somatic and visceral stimuli were measured by tail flick (TF) and colorectal distension (CD) tests, respectively. Measurements were performed once a day for 7 days. Challenge tests with intrathecal morphine were performed to assess the magnitude of tolerance on Day 5 and Day 7. The antinociceptive effect was evaluated by using the percent of maximal possible effect (%MPE). Morphine infusion produced significant increases in %MPEs in TF and CD tests, while the saline and K250 infusions did not show any changes. The M1 + K250 infusion significantly increased the %MPEs in TF and CD tests, although the M1 and K250 infusions alone showed no changes. M5 + K250 enhanced the increases of %MPEs in TF and CD tests compared with the M5 infusion alone. In the challenge tests, the M1 + K250 infusion showed no significant decrease in %MPEs and TF and CD tests. The M5 + K250 infusion significantly inhibited those decreases in %MPEs, although the M5 infusion showed significant decreases in TF and CD tests. We concluded that ketamine attenuated the development of morphine tolerance to antinociceptive effects and increased the somatic and visceral antinociception of morphine.

IMPLICATIONS

Intrathecally coinfused ketamine attenuated morphine tolerance to somatic and visceral antinociception and increased morphine antinociception at the spinal level. These results suggest that a combination of morphine with ketamine may have an advantage in long-term use of opioids for controlling visceral as well as somatic pain.

Positron emission tomography of esophageal carcinoma using (11)C-choline and (18)F-fluorodeoxyglucose: a novel method of preoperative lymph node staging

BACKGROUND

Accurate preoperative staging is an important but difficult problem in determining therapy for patients with esophageal carcinoma. Positron emission tomography (PET) is used with [methyl-(11)C]choline ((11)C-choline) and 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) to detect a variety of malignancies. The authors used PET with both of these agents to detect lymph node metastases in patients with esophageal carcinoma.

METHODS

Lymph node metastases in 33 patients with biopsy-proven esophageal carcinoma (16 patients with tumors classified as T1 and 17 patients with tumors classified as T2-4) was examined by PET using (11)C-choline and (18)F-FDG, and the accuracy of the results was correlated with pathology findings after surgery.

RESULTS

(11)C-choline PET was more effective than (18)F-FDG PET and computed tomography (CT) in detecting very small metastases localized in the mediastinum. It was ineffective, however, in detecting metastases localized in the upper abdomen, because of the normal uptake of (11)C-choline in the liver. (18)F-FDG PET was superior to CT in detecting metastases in the mediastinum and the upper abdomen, whereas (11)C-choline PET was superior to (18)F-FDG PET in detecting metastases in the mediastinum. When (11)C-choline PET and (18)F-FDG PET were used in combination, they were very effective in evaluating the lymph node status in both the mediastinum and the upper abdomen, and detected 85% of the metastatic lymph nodes (n = 46).

CONCLUSIONS

In this study, the combination of (11)C-choline PET and (18)F-FDG PET was very effective in evaluating the lymph node status of patients with esophageal carcinoma preoperatively.

The interaction of antinociceptive effects of morphine and GABA receptor agonists within the rat spinal cord

Previous reports indicate that there may be an interaction between gamma-aminobutyric acid receptors and opioid receptors systems within the spinal cord, the antinociceptive effects of which have not been elucidated. We examined the effects of intrathecally coadministered morphine and muscimol or baclofen on somatic and visceral antinociception in rats. The tail flick (TF) test and colorectal distension (CD) test were used to assess somatic and visceral antinociceptive effects, respectively. Motor function was also assessed. The measurements were performed for 180 min after the intrathecal administration of morphine (0.1-10 micrograms), muscimol (0.2-10 micrograms), baclofen (0.03-1 microgram), combination of morphine and muscimol or baclofen, or saline. Morphine, muscimol, or baclofen increased both TF latency and CD threshold in a dose-dependent fashion. Although morphine 0.1 microgram, muscimol 0.2 microgram, or baclofen 0.03 microgram alone did not significantly increase TF latency and CD threshold, the combination of morphine 0.1 microgram and muscimol 0.2 microgram or baclofen 0.03 microgram significantly increased both TF latency and CD threshold. The coadministration of muscimol or baclofen increased the antinociceptive effects of morphine in intensity and duration. None of the rats showed motor dysfunction after the coadministration of morphine and muscimol 0.2 microgram, although muscimol produced motor paralysis of the lower limbs in a dose-dependent fashion. Those results suggest a clinical relevance of the coadministration of mu-opioids and GABA receptor agonists for pain control.

IMPLICATIONS

We examined the antinociceptive interaction between morphine and muscimol or baclofen at the spinal level in rats. Intrathecal muscimol or baclofen potentiated both somatic and visceral antinociceptive effects of morphine.

[Antinociceptive effects of intrathecally administered GABA agonists at the spinal cord level]

The present study was designed to investigate antinociceptive effect of GABA agonists regarding visceral as well as somatic noxious stimuli. Following the approval by the institutional animal care committee, an intrathecal catheter was implanted in the subarachnoid space at the L 4/5 level in male Sprague-Dawley rats. The tail flick (TF) test and the colorectal distension test (CD) were used to measure responses to somatic and visceral stimuli, respectively. Threshold in TF test and CD test were measured at 5, 10, 15, 20, 30, 60, 90, 120 and 180 min after the intrathecal injection of 0.1, 1, 5, 20 micrograms of muscimol, 0.01, 0.1, 0.3, 1 microgram of baclofen or normal saline. Percent of maximum possible effect (%MPE) and %area under the curve (%AUC) were calculated by transforming response threshold in TF and CD tests. Repeated measure ANOVA followed by Fisher's PLSD test were used for statistical analysis. Muscimol 0.1 microgram increased mean %MPE in TF test at 10 min to 15% but not in CD test. Muscimol 1, 5 and 20 micrograms significantly increased %MPE at 5 min in TF and CD tests. Muscimol 20 micrograms produced 100%MPE for 180 min after drug injection. Baclofen 0.1, 0.3 and 1 microgram significantly increased %MPE at 5 min in TF and CD test. Antinociceptive effect in TF test seems to be greater than that in CD test. Muscimol caused motor disturbance but baclofen did not. It is concluded that intrathecally administered muscimol and baclofen produced somatic and visceral antinociception in a dose dependent fashion.

Regulatory network of mitomycin C action in human colon cancer cells

A network composed of activation and inactivation pathways to regulate mitomycin C (MMC) action is suggested to exist in human cancer cells. COLO201 colon cancer cells were stably transfected with human NQO1 cDNA that encodes NAD(P)H:quinone oxidoreductase (DT-diaphorase, DTD), and a clonal cell line with about 57-fold elevated DTD activity was obtained. Northern analysis revealed that expression of the NADPH:cytochrome P450 reductase (P450 reductase) gene was decreased in the transfectant, COLO201/NQO1, associated with the increase of NQO1 expression. Biochemical characterization of the cells showed a significant increase of the glutathione (GSH) content concomitantly with the decrease of the P450 reductase activity. As a result of these coordinated modulations, sensitivity of COLO201/NQO1 to MMC was not increased as compared to the parent cells. Analyses of inhibition by specific inhibitors of DTD, P450 reductase and glutathione S-transferase (GST) in 5 human colon cancer cell lines including the transfectant showed that DTD and P450 reductase play significant roles in MMC activation in cells with sufficiently high DTD activity and with marginal DTD activity, respectively. In contrast, GST appeared to participate in MMC inactivation in cells with a high level of GST activity. These results indicated that DTD, P450 reductase, GSH and GST may act together compensatively or competitively, depending on their levels in cells, to determine the cellular sensitivity to MMC.

Dihydropyrimidine dehydrogenase, multidrug resistance-associated protein, and thymidylate synthase gene expression levels can predict 5-fluorouracil resistance in human gastrointestinal cancer cells

Gene expression of dihydropyrimidine dehydrogenase (DPD) and newly multidrug resistance-associated protein (MRP) was found to correlate well with primary 5-FU resistance in 7 human gastrointestinal cancer cell lines. Although mRNA and protein levels of thymidylate synthase (TS) did not relate to the resistance, 5-FU treatment revealed a remarkable increase of TS expression. Such enhanced TS expression was more significant than DPD and MRP, and observed less in 5-FU sensitive cells. DPD and MRP expression levels can predict primary 5-FU resistance, and TS may be a potent predictor of cellular 5-FU resistance after 5-FU treatment.

Interaction of intrathecally infused morphine and lidocaine in rats (part I): synergistic antinociceptive effects

BACKGROUND

Synergistic antinociception of opioids and local anesthetics has been established in bolus injections but not in long-term use. The somatic and visceral antinociceptive effects of intrathecally infused morphine or lidocaine were characterized, and the nature of the interaction of those agents in rats was evaluated.

METHODS

Intrathecal catheters were implanted in rats. Morphine (0.3 to 10 microg x kg(-1) x h(-1)), lidocaine (30-1,000 microg x kg(-1) x h(-1)), a combination of those, or saline was infused intrathecally at a constant rate of 1 microl/h for 6 days. The tail flick and colorectal distension tests were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests and motor function tests were repeated on days 1, 2, 3, 4, and 6. Isobolographic analysis was performed on the results of the tail flick test to determine the magnitude of the interaction.

RESULTS

Intrathecally infused morphine produced dose-dependent antinociceptive effects in both the tail flick and the colorectal distension tests. Morphine showed a lower peak percentage maximum possible effect (%MPE) in the colorectal distension test than in the tail flick test. Intrathecal lidocaine also produced dose-dependent antinociceptive effects. Lidocaine infusion at 1,000 microg x kg(-1) x h(-1) caused motor impairment. Coinfusion of morphine 0.3 microg x kg(-1) x h(-1) and lidocaine 200 microg x kg(-1) x h(-1), which had no effects by themselves, significantly increased the percentage maximum possible effects (P < 0.01). Coinfused lidocaine potentiated the duration and the magnitude of morphine antinociception. Isobolographic analysis of the tail flick test on day 1 showed a synergistic interaction between morphine and lidocaine.

CONCLUSIONS

Morphine and lidocaine intrathecally coadministered synergistically potentiated the antinociceptive effects of each other. That coinfusion dramatically potentiated visceral antinociception, whereas the infusion of morphine alone showed little visceral antinociception.

Interaction of intrathecally infused morphine and lidocaine in rats (part II): effects on the development of tolerance to morphine

BACKGROUND

There has been little information regarding the effects of local anesthetics on tolerance to opioids, although chronic use of combination of opioids and local anesthetics is popular for pain control. This study was designed to examine the effects of lidocaine on morphine tolerance to somatic and visceral antinociception.

METHODS

Rats received a continuous intrathecal infusion of morphine (0.3-10 microg x kg(-1) x h(-1)), lidocaine (30-1000 microg x kg(-1). h(-1)), a combination of those, or saline. After 6- day infusion, intrathecal morphine challenge test (5 microg/10 microl) was performed, and time-response curve was constructed to assess the magnitude of tolerance. The tail flick (TF) test and colorectal distension (CD) test were used to measure somatic and visceral antinociceptive effects, respectively.

RESULTS

Antinociceptive effects in the TF and CD tests caused by morphine challenge were reduced (P < 0.01) in the morphine infused groups. The magnitude of the tolerance was inversely associated with the amount of morphine infused. Lidocaine infusion induced no different change in the morphine challenge test from that seen in the saline infusion group. Development of tolerance was greater in morphine 3 microg x kg(-1) h(-1) than in morphine 0.75 microg x kg(-1) x h(-1) + lidocaine 150 microg x kg(-1) x h(-1) despite their similar antinociceptive effects during intrathecal infusion. The infusion of a low dose of morphine (0.3 microg kg(-1) x h(-1)) did not reduce the antinociceptive effects in the challenge test.

CONCLUSION

Lidocaine in combination with morphine does not reduce tolerance to morphine nor develop cross-tolerance. The intrathecal infusion of morphine induced tolerance to somatic and visceral antinociception in a dose-dependent fashion.

Characteristics of tolerance to somatic and visceral antinociception after continuous epidural infusion of morphine in rats

A continuous epidural infusion of morphine may cause a complicated tolerance to develop, depending on the spinal and supraspinal sites. We designed this study to clarify the characteristics of the tolerance to somatic and visceral antinociception after epidural morphine infusion. Rats received epidural infusion of morphine at the rates of 50 or 100 microg kg(-1) h(-1), or isotonic sodium chloride solution for 7 days. The tail-flick (TF) test and colorectal distension (CD) test were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests were performed on Days 1, 2, 3, 4, and 7. After 7 days, time-response curves after epidural morphine (10 microg) or intraperitoneal morphine (3 mg) challenge tests were conducted to assess the magnitude of tolerance. Epidurally infused morphine significantly increased percent maximal possible effects (%MPEs) (P < 0.05) in both the TF and CD tests, depending on the concentration of morphine. In the epidural morphine challenge test, increases in %MPEs were significantly attenuated (P < 0.05) in the morphine-infused group compared with the isotonic sodium chloride solution-infused group. The increases in %MPEs in the intraperitoneal challenge test were also attenuated in the morphine-infused group. We conclude that morphine tolerance to both somatic and visceral antinociception develops rapidly during epidural infusion and is based on the development of tolerance at the systemic, as well as the epidural, level.

IMPLICATIONS

A continuous epidural infusion of morphine rapidly induces tolerance to visceral and somatic antinociception in rats. This development is based on the development of tolerance at the systemic, as well as the epidural, level.

Antinociceptive effects of intrathecal L-type calcium channel blockers on visceral and somatic stimuli in the rat

L-type calcium channels can modulate neuronal transduction in the spinal cord. However, their role in noxious information processing in animals that are physiologically intact has not been elucidated. We evaluated the effects of L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception at the level of the spinal cord. Intrathecal catheters were inserted at the L4-5 level in Sprague-Dawley rats. The tail flick (TF) test and colorectal distension (CD) test were used to assess somatic and visceral antinociceptive effects, respectively. Motor function was assessed by posture and muscle tone in the limbs. TF latency and CD threshold were measured before and for 180 min after the intrathecal administration of verapamil (50, 100, 300, and 500 microg), diltiazem (100, 300, 500, and 1000 microg), or isotonic sodium chloride solution. The percent maximal possible effect (%MPE) was calculated by transforming response threshold in TF and CD tests. Intrathecally administered diltiazem or verapamil increased both TF latency and CD threshold in a dose-dependent fashion. Isotonic sodium chloride solution, diltiazem 100 microg, and verapamil 50 microg did not increase %MPE in either test. Diltiazem 300 or 500 microg or verapamil 300 or 500 microg significantly (P < 0.05) increased %MPE, with the peak effects 5 min after administration and short-duration antinociception. %MPE was 100% until 15 min after the administration of diltiazem 1000 microg, and significant antinociception continued until 180 min in the TF test. Motor paralysis was observed after the administration of the larger dose of each drug. We demonstrated that intrathecally administered L-type calcium channel blockers diltiazem or verapamil produced both somatic and visceral antinociception and motor block dose-dependently.

IMPLICATIONS

We examined the effects of intrathecally administered L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception in rats. L-type calcium channel blockers produced antinociceptive effects, suggesting a possible clinical application to control pain.

[Electron microscopic observations of the conjunctiva in epidermolysis bullosa hereditaria]

A 35-year-old female had been clinically diagnosed as having epidermolysis bullosa hereditaria since her skin formed blisters from the time of her birth. Her left and right corneas become clouded at the age of 17 and 31 years, respectively. She was diagnosed as having bilateral secondary glaucoma at the age of 31 years and was medicated with antiglaucoma drugs. When examined by us, both corneas were invaded by conjunctival tissues and intraocular pressure in both eyes was 38 mmHg. Visual acuity was 0.09 (n.c.) in the right eye and she had no light perception in the left eye. A trabeculectomy OD was performed at our hospital. For confirmatory diagnosis, a pathological examination of the conjunctival and dermal tissues was done. Electron microscopic study demonstrated blister formation beneath the basal lamina and lost anchoring fibrils of both tissues. This finding confirmed that she had a receive form of dystrophic epidermolisis bullosa. This is a rare case of dystrophic epidermolisis bullosa with severe corneal changes and glaucoma diagnosed from electron microscopic observations.

Congenital extension contracture of metacarpophalangeal joints

We report a case of congenital extension contracture of the fifth metacarpophalangeal joints in a 15-year-old boy who had no associated anomalies and was successfully treated by surgery. Congenital extension contracture of bilateral metacarpophalangeal joints has not been reported previously, and the entity can be considered to be a new subgroup of distal arthrogryposis with congenital distal limb contracture.

Antinociceptive effects of ONO-9902, an enkephalinase inhibitor, after visceral stress condition in rats

PURPOSE

The present study was designed to examine the antinociceptive effects of orally administered ONO-9902, an enkephalinase inhibitor, on both somatic and visceral pain after visceral stress conditions.

METHODS

Twenty six male rats were examined. Tail-flick (TF) and colorectal distension (CD) tests were used to determine somatic and visceral antinociceptive effects, respectively. Measurements were performed in rats under immediate post-stress conditions (group ST; n = 14) and in rats nor under stress conditions (group NST; n = 12). In the stressed group, the same device, CD, for visceral antinociceptive effects was used for visceral stress and was applied with an intracolonic pressure of 60 mmHg for 20 min after drug administration. The TF latency and CD threshold were measured before and at 30, 40, 50, 60 and 90 min after administration of ONO-9902 300 mg.kg-1 or distilled water.

RESULTS

Orally administered ONO-9902 did not produce any changes in the % maximum possible effect (%MPE) in either TF or CD tests in the unstressed group. In the stressed group, %MPE in the CD test increased 18% and 31% at 30 and 40 min, respectively, after oral administration of ONO-9902 compared with the control group (P < 0.05). However, %MPE to TF test did not alter even after the CD-induced stress condition.

CONCLUSION

These results suggest that ONO-9902 may have analgesic effects on visceral pain but not on somatic pain under immediate post-stress conditions.

Intrathecal prostaglandin E1 produces a long-lasting allodynic state

The existence of prostaglandin (PG) receptors in the spinal cord has been demonstrated, but their role in sensory processing is not yet well defined. PGE1 is widely used clinically as a vasodilator. The present study was designed to investigate the effects of intrathecally administered PGE1 on the transmission of different types to sensory information, including that associated with noxious somatic, noxious visceral, and non-noxious somatic stimulation. The tail-flick (TF) test was employed to measure responses to noxious somatic stimuli, and the colorectal distension test was used to examine responses to noxious visceral stimuli. Withdrawal response to mechanical pressure produced by Semmes-Weinstein mono-filaments (SWMs) was measured as an assessment of sensitivity to non-noxious mechanical somatic stimulation. TF latencies and colorectal distension thresholds decreased for a short time (10-20 min) following the intrathecal (i.t.) administration of both 100 ng or 500 ng of PGE1. In sharp contrast to these short duration effects, there was a long-lasting increase in agitation scores (allodynia) produced by 3 different intensities of SWMs (0.217, 0.745 and 2.35 g) after administration of PGE1. The changes in agitation scores to SWMs were dependent on the dose of PGE1 and the intensity of stimulation. This increase of agitation score was seen when PGE1 was administered through the i.t. catheter or by direct i.t. puncture and the increase lasted for at least 2 days after drug administration. Intrathecal administration of saline, however, did not produce any changes in TF latencies, colorectal distension thresholds, or agitation scores produced by SWMs. No significant histological difference was seen between spinal cords exposed to 500 ng PGE1 and saline 48 h after drug administration. These results demonstrate that PGE1 may trigger a hypersensitive (allodynic and/or hyperalgesic) state in sensory processing pathways at the spinal level. They also indicate that long-lasting changes in processing of non-noxious, but not noxious, information produced by PGE1 continues after the disappearance of the direct action of PGE1.

Pregnancy enhances the antinociceptive effects of extradural lignocaine in the rat

We have compared the antinociceptive effect of extradural lignocaine on somatic and visceral nociception in pregnant (n = 11) and non-pregnant rats (n = 9). Colorectal distension (CD) threshold and tail flick (TF) latency were measured as visceral and somatic nociception, respectively, for 60 min after extradural injection. On days 19, 20 and 21 of pregnancy, rats received lignocaine 200, 400 or 800 micrograms or normal saline via a chronically implanted lumbar extradural catheter. Extradural lignocaine produced dose-dependent antinociceptive effects on TF latency and CD threshold. Lignocaine 200 or 400 micrograms produced significantly greater peak effects in pregnant than in non-pregnant rats. Although the peak effects with lignocaine 800 micrograms were not different between groups, the duration of the effects were longer in pregnant compared with non-pregnant rats. We conclude that both somatic and visceral antinociceptive effects of extradural lignocaine were potentiated in pregnant rats near term compared with those in non-pregnant rats.

Synergistic antinociceptive interaction after epidural coadministration of morphine and lidocaine in rats

BACKGROUND

Clinically, epidural coadministration of opioids and local anesthetics has provided excellent analgesia for various types of pain. However, information about the interaction of these drugs when administered epidurally is limited. Therefore, we evaluated the antinociceptive interaction between morphine and lidocaine on both somatic and visceral noxious stimuli in the rat.

METHODS

Male Sprague-Dawley rats weighing 300-350 g had epidural catheters implanted at T13-L1. Every rat was tested with both the tail flick test, a somatic noxious stimulus, and the colorectal distension test, a visceral noxious stimulus. In the colorectal distension test, the response threshold was defined by the pressure within the intracolonic balloon required to trigger abdominal contraction. Tail flick latency and colorectal distension threshold were measured before and for 180 min after the administration of morphine, lidocaine, or combinations of those drugs. To characterize the interaction, isobolographic analysis was performed with a fixed morphine: lidocaine dose ratio of 1:1,000.

RESULTS

Epidural morphine (0.1-10 micrograms) and lidocaine (100-800 micrograms) increased the tail flick latency and colorectal distension threshold in a dose- and time-dependent fashion. The epidural injection of morphine (0.1-1 microgram) mixed with lidocaine (100 or 200 micrograms) significantly increased the peak effect and prolonged the duration of effects compared with each drug alone in both nociceptive tests. Areas under the curves, calculated to express overall magnitude and duration of antinociceptive effects, were significantly increased by combinations as compared with each drug alone, especially with morphine 0.1 microgram and lidocaine 100 or 200 micrograms, each of which alone produced no change in the area under the curve. Isobolographic analysis revealed that epidural morphine and lidocaine interact synergistically at 10, 20, and 30 min after injection in both somatic and visceral nociception tests. Both potency ratio analysis and fractional analysis confirmed the finding of the isobolographic analysis. Epidural naloxone antagonized the antinociceptive effects produced by the combination.

CONCLUSION

These data demonstrate that epidurally coadministered morphine and lidocaine produce synergistic analgesia and prolong the duration of analgesia in tests of somatic and of visceral nociception.

[A case of advanced gastric cancer responding to an FAP (5-FU, ADM, platinum compounds) combined chemotherapy]

An experience with an advanced gastric cancer patient with metastases to bilateral breasts, uterus, abdominal lymph nodes, bilateral axillary and supraclavicular lymph nodes, and bone marrow, responded extremely well to an FAP combined chemotherapy as reported here. The patients received four courses of 5-FU (370 mg/m2/day, for five days, continuous infusion), ADM (30 mg/m2 on day 1, i.v.) and CDDP (55 mg/m2 on day 1, i.v.) every 3 weeks in our hospital. This was followed by 7 months of outpatient therapy with 5-FU (550 mg/m2 on day 1, i.v.), ADM (30 mg/m2 on day 1, i.v.) and CBDCA (330 mg/m2 on day 1, i.v.) for every 4 weeks. The complete remission of the primary and metastatic lesions, that was confirmed by the histological examinations, was obtained after 10 months since the initial treatment started. The toxicity was generally moderate, however, the alopecia was severe. The patient has been living for 6 months without any signs of the recurrence after the complete remission obtained.

Clinicopathological and immunohistochemical study of basal cell carcinoma with reference to the features of basement membrane

One hundred and thirty-five cases of basal cell carcinoma (BCC) were investigated, focusing upon factors determining a postoperative prognosis. Out of the 135, nine tumors on the face recurred. All of these nine tumors were insufficiently extirpated at the initial operation, and showed micronodular or infiltrative patterns with stromal fibrosis. Dividing the degree of dermal invasion into four levels, all tumors with recurrence reached levels 3 and 4, the two deeper groups. The immunohistochemical study using anti-laminin and anti-type IV collagen antibodies showed various changes of staining pattern around tumor cell nests, such as attenuation, disruption, and thickening of basement membrane, in contrast with the normal thinly continuous staining around nontumorous control epidermis. The disruption of basement membranes was remarkable around the tumor cells showing a micronodular growth pattern, although the discontinuity of basement membrane was observed in all types of BCCs to a greater or lesser degree. Ultrastructural thickening, multiplication, or discontinuity of basement membranes were found in all 19 cases examined with a greater or lesser degree, although they were most frequently observed around the cell nests showing micronodular growth patterns. It was concluded that deep dermal and marginal invasions were the most ominous signs of recurrence of BCCs. Although the disruption of basement membranes might participate in the local aggressiveness of BCCs, especially in the tumor cells showing micronodular infiltrative growth, other factors may concern the recurrence of BCCs.

[Clinical studies of in vitro chemosensitivity test evaluated by ATP assay of gastrointestinal cancer]

In order to determine the most effective anticancer agent for individual human tumor, we have performed several chemosensitivity tests, such as human tumor clonogenic assay (HTCA), succinic dehydrogenase inhibition test (SDI-T), nude mouse isotope assay (NM-IA) and subrenal capsule assay (SRCA). In this study, an novel in vitro chemosensitivity test (ATP-assay) measuring ATP amounts of cancer cells was carried out in 69 fresh gastro-intestinal tumors obtained at surgery. As the results, the evaluable rate of ATP assay was 87.0%. The positive rate of ATP assay against all tumors were 13.3% in mitomycin-C (MMC), 11.7% in adriamycin (ADM), 13.3% in 5-fluorouracil (5-FU) and 18.3% in cis-diamminedichloroplatinum (CDDP), respectively. Overall predictive accuracy rate was 82.8%. The comparative study of the survival rates of the patients with stage IV gastric cancer, receiving sensitive anticancer agents assayed by ATP assay, and those receiving negative anticancer agents revealed that the survival rate of the patients treated with sensitive drugs was longer with Kaplan-Meier analysis. From these results, it seems reasonable to conclude that ATP assay is of value in determining the chemosensitivity of gastrointestinal cancer in each patient.

Hair follicle nevus with hyperplasia of smooth and striated muscle

We report a peculiar nevus which occurred on the left side of the chin of an 18-year-old male. It had been present for four years and had grown rapidly during the last year. Histologically, many hair follicles, smooth muscles, and striated muscles were found within the reticular dermis. The hair follicles were accompanied by mature sebaceous glands; numerous eccrine glands were seen in the middle and deep dermis. Immunohistochemical stain and phosphotungstic acid hematoxylin stain supported the fact that the muscles seen between the follicles were both smooth and striated. This nevus was considered to be a hair follicle nevus accompanied by hyperplasia of smooth muscles and striated muscles.

Prediction of the resistance of human tumors to adriamycin by chemosensitivity tests and DNA analysis of the multidrug resistance gene

In order to predict natural resistance to Adriamycin (ADM), the amplification of multidrug resistance gene 1 (MDR1) was investigated in 50 human cancer specimens using Southern blot analysis. Genomic DNA was extracted from both human solid tumors and adjacent normal tissues for the analysis. MDR1 gene amplification was not observed in any of the patients tested, including 5 patients in whom ADM was not clinically effective. On the other hand, chemosensitivity tests performed on the tumor cells of these 5 patients indicated resistance to ADM. Our results therefore indicate that MDR1 gene amplification is rarely seen among clinical samples and that conventional chemosensitivity tests might be more useful for the prediction of ADM resistance in cancer patients than the analysis of MDR1 gene amplification.

Antitumor effect of KW2149, a new mitomycin derivative, administered by different modalities

The effectiveness of a new mitomycin derivative, KW2149, against human tumors was evaluated by the 4 days subrenal capsule assay (SRCA) and the nude mice screening assay (NMSA). Evaluation by the SRCA showed a 50% response rate at a maximum dose of 3.8 mg/kg for 3 consecutive days. When evaluated by NMSA, the response rate was 100, 75 and 25% after the intermittent administration of 7.5, 5.6 and 4.5 mg/kg (q4dx3) respectively. Although the efficacy was reduced when mice were administered a single dose equivalent to the intermittent one, the new analog was along more effective than MMC administered by either modality.

The histological assessment and evaluation of a 4 day subrenal capsule assay by the percentage inhibition of DNA/protein

A four day subrenal capsule assay was investigated in order to determine its ability to clinically predict tumor chemosensitivity. To establish more objective and accurate evaluation criteria, a histological assessment and measurement of the DNA and protein content of excised tumor implants was conducted in ddY mice. The histological studies provided qualitative results concerning the percentage of cancer cells in the xenograft, the number of mitoses, the amount of necrosis, and the extent of lymphocytic infiltration. The DNA content was measured by a modified version of the Schmidt-Thannhauser-Schneider method and the protein content was estimated using the Bio-Rad protein assay. The percentage of cancer cells in the xenograft correlated poorly with the relative increase in tumor size, weight and the percentage inhibition of DNA/protein (per cent DNA/protein), however, the per cent DNA/protein correlated well with the clinical effects in 85.7 per cent of the tumors studied. Moreover, the histological assessment information was only consistent with those results obtained for per cent DNA/protein in the control group.

Chemosensitivity tests in colorectal cancer patients

In order to assess the usefulness of chemosensitivity tests in the treatment of colorectal cancer, 71 tumor specimens were tested for chemosensitivity in the following assays: nude mouse isotope assay (NMIA), subrenal capsule assay (SRCA), human tumor clonogenic assay (HTCA) and adenosine triphosphate inhibition assay (ATPA). The agents examined were: mitomycin C (MMC), 5-fluorouracil (5-FU), cyclophosphamide (CPM), adriamycin (ADM) and cis-diamminedichloroplatinum (CDDP). The evaluability rates were 90.8, 93.9 and 92.3 per cent in NMIA, SRCA and ATPA, respectively, but only 42.9 per cent in HTCA. The tumor response rates were 50.8, 45.2, 16.7 and 33.3 per cent in NMIA, SRCA, HTCA and ATPA, respectively. Individual drug sensitivity rates differed among all 4 assays, ranging from 0 to 33.3 per cent. In the arbitrary judgment of the 4 assays, the most sensitive agent was CDDP, followed by CPM, ADM, 5-FU and MMC. In the prospective study, predictive accuracy rates of the clinical responses were 81.3, 66.7, 100, 100 and 76.5 per cent in NMIA, SRCA, HTCA, ATPA and the arbitrary judgment, respectively. A significant correlation between the survival time and the results of SRCA was detected retrospectively. These results suggested that colorectal cancer might not be completely resistant to anticancer agents, and that chemosensitivity tests might be useful in the individual therapy of colorectal cancer patients.

[Comparative study on the anticancer activities of KW2149 and mitomycin C against human tumor xenografts using subrenal capsule assay]

The anticancer activity of KW2149, a new derivative of mitomycin C (MMC), was investigated against 5 human tumor xenografts derived from digestive organs using 4-day subrenal capsule assay (SRCA). Normal immunocompetent mice were used in this assay. For the comparative study, KW 2149 and MMC were administered intraperitoneally for 3 days after implantation, and the anticancer activity and the weight loss of mice were evaluated. The total doses were determined as 1/2, 1/3 and 1/4 of LD50 value of each anticancer agent. The anticancer activities of the two drugs were almost the same with no significant difference in 3 xenografts. Thus, it may be suggested the difference of the anticancer spectrum between the two drugs. The anticancer activity of KW2149 indicated higher correlation with the administered doses as compared with MMC. The toxicity of KW2149 was almost the same as MMC according to the weight loss of mice.

[Comparison of succinic dehydrogenase inhibition test with adenosine triphosphate inhibition assay for human solid tumors as in vitro chemosensitivity tests]

In order to determine the most effective anticancer agents for individual human tumor, succinic dehydrogenase inhibition test (SDI-T) and adenosine triphosphate inhibition assay (ATP-A) as in vitro chemosensitivity tests were performed. Fifty tumors and 57 tumors derived from cancer patients surgically methods were examined by SDI-T and ATP-A respectively. As the results, the evaluable rate was 70% by SDI-T and 94.7% by ATP-A, respectively. With SDI-T, the positive rate against all tumors was 51.4% in mitomycin-C (MMC), 42.9% in adriamycin (ADM), 20.0% in 5-fluorouracil (5-FU), 54.3% in cis-diamminedichloroplatinum (CDDP). On the other hand, with ATP-A, that was 20.4% in MMC, 29.5% in ADM, 20.6% in 5-FU, 20.4% in CDDP, respectively. Retrospective and prospective clinical trials were also carried out to determine the usefulness of both assays. With SDI-T, overall predictive accuracy rate was 57.1% while with ATP-A that was 88.9%. Furthermore, the rates of sensitivity for the same tumors using SDI-T and ATP-A were compared. The rate of the same sensitive cases in both assays were 30% with MMC, 70% with 5-FU, 42.1% with ADM, 36.8% with CDDP, respectively. In conclusion, it is suggested that ATP-A was more useful than SDI-T as in vitro chemosensitivity test to determine the most adequate drug for cancer patients.

[Evaluation and problems of second-look operations in resectable gastric cancer]

During the period from June 1973 to December 1985, one thousand and ninety-seven patients with primary gastric cancer have been operated on in our Dept. of Surgery. Of the 1097 gastric cancer patients, 59 were reoperated and evaluated for chemotherapeutic effects. The cases were 21/548 (3.83%) for absolute curatively resection, 16/202 (7.92%) for relative curatively resection, 9/64 (14.0%) for relatively noncurative resection and 13/283 (4.59%) for absolutely noncurative resection, respectively, The median survival period from primary gastrectomy to second look operation was less than 2 years, and the prognoses were not very good. The factors of relaparotomy were peritoneal dissemination 44/59 (78.6%), invasion to contiguous structures, lymph node metastases and liver metastasis. Those with local recurrence or remnant stomach cancer could be resected in 5 cases, and one patient was well more than 2 years following surgery. The reoperation procedures were reconstruction of artificial anus, intestinal anastomosis or intestinal fistula. Some 7 of 59 patients were found to be entirely beyond surgical aid at the second look operation and were administered large-dose OK-432 or ADM patch method. These methods are suggested for their usefulness for peritoneal dissemination.

[Experimental study of normal liver regeneration in hepatic arterial infusion with degradable starch microspheres (DSM)]

Influence of hepatic arterial infusion with degradable starch microspheres (DSM) or with anti-cancer drug or with both for normal liver regeneration in rat was determined by histological and microautoradiographical examination and liquid scintilation before or after 70% hepatectomy. DSM was seen in interlobular artery in early phase after hepatic arterial infusion, but disappeared into the central vein by degrees for 2 hours later. Adriamycin (ADM) in serum was detected for a long time after hepatic arterial infusion with DSM + ADM. In the heart muscle, a significantly lower concentration of ADM was seen in the DSM + ADM group than in the ADM only group. In the case of hepatic arterial infusion with DSM only after hepatectomy, there was no influence on normal liver regeneration. No significant difference was seen between hepatic arterial infusion and intravenous infusion with ADM only. However, in the case of hepatic arterial infusion with DSM + ADM after hepatectomy, a significant difference was seen in the inhibition of liver regeneration from any other groups.

[Anticancer activities of a new mitomycin derivative KW 2149, against human tumors xenografted into nude mice]

Anticancer activity of KW 2149, a new derivative of mitomycin C (MMC), was investigated using 4 human tumors xenografted into nude mice. The basic methodology was essentially the same with NCI's therapeutic protocol. For the comparative study, KW 2149 or MMC was administered intraperitoneally at a schedule of q4d X 3. Daily doses were determined as a 1/3, 1/4 and 1/5 of LD50 value of each anticancer agent (7.5 mg/kg, 5.6 mg/kg and 4.5 mg/kg for KW 2149, and 2.7 mg/kg, 2.1 mg/kg and 1.7 mg/kg for MMC). Anticancer activity of KW 2149 seemed to be dependent on the doses. Comparing with MMC, KW 2149 produced higher response rates at the doses of 1/3 and 1/4 of LD50 and was less toxic judging from the decrease of the body weight. This study may indicate an utility of KW 2149, as a new anticancer agents, or suggest the difference of anticancer activities between these two agents.

The indications of chemosensitivity tests against various anticancer agents

In order to determine the indications of chemosensitivity tests against various anticancer agents, clinical trials of 4 different assays, namely; nude mouse isotope assay (NMIA), subrenal capsule assay (SRCA), human tumor clonogenic assay (HTCA) and adenosine triphosphate inhibition assay (ATPA), were performed on 391 patients. Analysis of the correlation between assay results and clinical effects presented the possibility of determining the indications as follows; (1) The positive clinical response of mitomycin C (MMC) should be predicted by ATPA; (2) The clinical tumor resistance against MMC should be predicted by SRCA; (3) Concerning 5-fluorouracil (5-FU) the chemosensitivity test (ATPA) should only be used for the detection of tumor resistance in the assay; (4) The poor results of this study indicated the difficulty of correctly estimating the effects of cyclophosphamide (CPM); (5) The perfect prediction of clinical effects in this trial indicated that cis-DDPlatinum (CDDP) should be estimated by SRCA; (6) The positive clinical tumor response against adriamycin (ADM) should be predicted by SRCA, while the negative one should be predicted by HTCA; and (7) ATPA showed good potential for estimating not only time dependent drugs such as 5-FU, but also cytotoxic drugs.

[Inhibition of thymidylate synthetase and antiproliferative effect by 1-hexylcarbamoyl-5-fluorouracil]

In order to estimate tumor chemosensitivity of fluoropyrimidine derivative, inhibition of thymidylate synthetase (TS) was investigated using a nude mouse experimental system. Four human tumors xenografted in nude mice; H-111, SH-8 and SH-10, each established from gastric cancer, and EH-1 from esophageal cancer, were used. When the transplanted tumor volumes reached to approximately 200 mm3, 1-hexylcarbamoyl-5-fluorouracil (HCFU) was given for 5 days. Tumors was removed for the measurement of total and free TS at 0 hr, 6 hrs and 24 hrs after the last administrations. Simultaneously, the anti-proliferative effects were investigated according to the therapeutic protocol of NCI. No positive correlation between the inhibition rate of TS and the anti-proliferative effects was observed, although the absolute values of free TS were similar to the tumor inhibition rates. The measurement of total TS provided a highest concentration in SH-8, while extremely low in EH-1. On the analysis of free TS, a significant increase of the concentration was observed at 24 hrs after the last administration compared with at 6 hrs in SH-8. These results indicate that free TS had a potentiality as a new parameter for predicting tumor chemosensitivity of fluoropyrimidine derivative and the analysis of TS should be affected strongly by the characteristics of enzymic activity of examined tumor.

[Combined effects of interferon alpha-A/D with fluoropyrimidine derivatives in the subrenal capsule assay]

The combined effects of interferon alpha-A/D (IFN alpha-A/D) with 5-fluorouracil and fluoropyrimidine derivatives such as 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur), UFT, 1-hexylcarbamoyl-5-fluorouracil (HCFU) and 5'-deoxy-5-fluorouracil (5'-DFUR), were examined by 4-day subrenal capsule assay. Four human tumor xenografts serially transplanted in athymic mice, H-111, SH-10 established from gastric cancers, CH-4 and CH-5 from colon cancers, were used. In this experiment, the adequate dose of each agent was estimated as 50 mg/kg for 5-FU, 473 mg/kg for tegafur, 433 mg/kg for UFT, 50 mg/kg for HCFU, 185 mg/kg for 5'-DFUR and 1 x 10(5) IU for IFN alpha-A/D, respectively. When synergistic, additive and subadditive effects were defined as positive combined effects, all combinations produced positive combined effects against H-111 and CH-5, while negative ones were observed for all combinations against CH-4. The combinations of 5-FU, HCFU and 5'-DFUR with IFN alpha-A/D produced synergistic effects against SH-10. These results indicate that the combination therapy of 5-FU and fluoropyrimidine derivatives with IFN alpha-A/D would be useful.