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.