Prevalence of sodium-glucose transporter 2 inhibitor-associated diabetic ketoacidosis in real-world data: A systematic review and meta-analysis

BACKGROUND

The U.S. Food and Drug Administration (FDA) revised the labels of sodium-glucose transporter 2 (SGLT2) inhibitors in December 2015 to inform users regarding the risk of diabetic ketoacidosis (DKA). As more drugs of this class are approved and their indications are expanded, this serious adverse effect has been increasingly reported.

OBJECTIVE

This review evaluated observational studies to inform the prevalence of SGLT2-inhibitor-associated DKA compared with other antihyperglycemic agents.

METHODS

A systematic review was conducted in PubMed and EMBASE until 19 July 2022 (PROSPERO: CRD42022385425). We included published retrospective cohort active comparator/new user (ACNU) and prevalent new user studies assessing SGLT2-inhibitor-associated DKA prevalence in adult patients with type 2 diabetes mellitus (T2DM) against active comparators. We excluded studies which lacked 1:1 propensity score matching. The JBI Checklist for Cohort Studies guided the risk-of-bias assessments. Meta-analysis was conducted based on the inverse variance method in R software.

RESULTS

Sixteen studies with a sample of 2,956,100 nonunique patients met the inclusion criteria. Most studies were conducted in North America (n = 9) and adopted the ACNU design (n = 15). Meta-analysis of 14 studies identified 33% higher DKA risk associated with SGLT2 inhibitors (HR = 1.33, 95% CI: 1.14-1.55, P < 0.01). Meta-regression analysis identified the study location (P = 0.02), analysis principle (P < 0.001), exclusion of chronic comorbidities (P = 0.007), and canagliflozin (P = 0.04) as significant moderator variables.

CONCLUSIONS

Despite limitations related to heterogeneity, generalizability, and misclassification, the results of this study show that SGLT2 inhibitors increase the prevalence of DKA among adult T2DM patients in the real world. The findings supplement evidence from randomized controlled trials (RCTs) and call for continued vigilance.

Age at menopause and lifetime cognition: Findings from a British birth cohort study

OBJECTIVE

We investigated whether cognitive performance between ages 43 and 69 years was associated with timing of menopause, controlling for hormone replacement therapy, childhood cognitive ability, and sociobehavioral factors.

METHODS

We used data from 1,315 women participating in the Medical Research Council National Survey of Health and Development (a British birth cohort study) with known age at period cessation and up to 4 assessments of verbal memory (word-learning task) and processing speed (letter-cancellation task) at ages 43, 53, 60-64, and 69. We fitted multilevel models with linear and quadratic age terms, stratified by natural or surgical menopause, and adjusted for hormone replacement therapy, body mass index, smoking, occupational class, education, and childhood cognitive ability.

RESULTS

Verbal memory increased with later age at natural menopause (0.17 words per year, 95% confidence interval [CI]: 0.07-0.27, p = 0.001); an association remained, albeit attenuated, after full adjustment (0.09, 95% CI: 0.02-0.17, p = 0.013). Verbal memory also increased with later age at surgical menopause (0.16, 95% CI: 0.06-0.27, p = 0.002), but this association was fully attenuated after adjustment. Search speed was not associated with age at menopause.

CONCLUSION

Our findings suggest lifelong hormonal processes, not just short-term fluctuations during the menopause transition, may be associated with verbal memory, consistent with evidence from a variety of neurobiological studies; mechanisms are likely to involve estrogen receptor β function. Further follow-up is required to assess fully the clinical significance of these associations.

[AUFRAP therapy: combined modality treatment of malignant gliomas with intraarterial infusion of ACNU]

A method of combination therapy was proposed for the treatment of malignant gliomas, and the clinical results were reported. This combination consisted of ACNU (nimustine), UFT (tegafur + uracil), Radiation, vitamin A and PSK (krestin), and was named AUFRAP therapy. Intracarotid infusion of ACNU (100 or 150 mg/body) was done after the administration of vitamin A (100,000 units), in the first and last week of radiation therapy with a total dose of 60-70 Gy. UFT (400-600 mg/day) and PSK (3g/day) were also given orally. After the induction of remission, patients were treated in the outpatient clinic under a similar maintaining protocol. Two patients who received 150 mg of ACNU and daily 600 mg of UFT in combination with radiation therapy showed severe myelosuppression in the early stage of treatment, and the combination therapy was aborted. Two of four patients who received 100mg of ACNU and daily 400mg of UFT did not show such severe side effects and two showed transient, moderate myelosuppression and vomiting. The serum phenitoin concentration doubled and was thought to be a side effect of tegafur. All four patients completed the induction protocol and follow-up CT scans disclosed shrinkage of the remained tumors, decreased contrast enhancement or no evidence of recurrence. Interactions of these drugs and radiation were discussed and the literature was reviewed.

[Multidisciplinary treatment of advanced neuroblastoma--experience in treatment with the protocol of a group study supported by a grant from Ministry of Health and Welfare]

Ten patients in stages III or IV of neuroblastoma have been receiving treatment on the basis of a group study protocol that is supported by grant from the Ministry of Health and Welfare. Their chemotherapy regimen has consisted of a combination of cyclophosphamide, vincristine, THP-adriamycin, cisplatin, nimustine and dacarbazine. Surgery has been performed on all patients and in 7 patients their primary tumors were resected either as a delayed primary operation or a second look operation. Radiotherapy has been used for four patients at a total dose of 22-40 Gy. Six patients still survive (survival time: 5-27 months) with time spans that have ranged from 2-19 months of complete response. Major complications have been renal insufficiency, hearing loss, cardiac insufficiency, and bone marrow suppression, We focus mainly on the problems of this multidisciplinary treatment protocol.

Instability of Mex- phenotype in human lymphoblastoid cell lines

Three lymphoblastoid cell lines (LCLs) had extremely low activities of O6-alkylguanine-DNA alkyltransferase (O6-AGT), and were classified as Mex-. They were highly sensitive to cell killing by 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosoure a hydrochloride (ACNU), whereas NMO2, a Mex+ LCL with a high O6-AGT activity, was resistant to the agent. Small fractions of these Mex- LCLs survived the treatment with 10 micrograms/ml of ACNU for 24 h, and the surviving cells were found to be resistant to subsequent treatments with the agent. In addition, they contained O6-AGT activities comparable to that of NMO2 and were therefore regarded as Mex+. These results suggest that the Mex- phenotype in LCLs is unstable.

In vitro damage of isolated DNA from two brain tumor cell lines induced by a water-soluble antitumor nitrosourea

We report the DNA sites damaged by the antitumor drug, nimustine hydrochloride (ACNU), in highly reiterated DNA sequences of rat glioma cells. A reiterated fragment of 370 base pairs (bp), obtained after Hind III restriction endonuclease digestion of rat glioma C6 or 9L cells DNA, was divided into 167 and 203 bp by subsequent Hae III enzyme reaction. The reaction of end-labelled 167 and 203 bp fragments with ACNU resulted in scission breaks corresponding to the locations of guanine. Moreover, ACNU and subsequent piperidine hydrolysis produced more frequent breaks of the phosphodiester bonds at the guanine positions, thus forming alkali-labile sites. These results indicate that the preferred site of DNA strand scission induced by ACNU is at guanine positions.

Combination chemotherapy for multiple myeloma with melphalan, ifosfamide, prednisolone, nitrosourea and vincristine

Melphalan, ifosfamide, prednisolone, nitrosourea [1-(4-amino-2-methyl-5-pyrimidyl)-3-(2-chloroethyl)-3-nitrosourea hydrochloride, ACNU or 1, 3-bis (2-chloroethyl)-1-nitrosourea, BCNU] and vincristine (MIP-NV) were given in combination to 48 patients with multiple myeloma. The response rate was 57% in previously untreated patients, and 39% in previously treated patients. The median survival time of previously untreated patients in stage IA + IIA was 49 months, and that of patients in stage IIIA + B was 27 months. The median survival time of stage III patients depended significantly on the duration of remission. The duration of remission and survival time of patients with relief of pain and improvement in daily activity were significantly longer than those of patients without such effects. Age, sex, blood hemoglobin concentration and bone lesion were important prognostic factors. As for the side effects, leukopenia (less than 1,000/microliter) and thrombocytopenia (less than 5 X 10(4)/microliter) occurred in 10.4% and 2.1% of the patients, respectively. It was concluded that multiple drug combination therapy with MIP-NV (MIP-NV therapy) was effective for patients with multiple myeloma at all clinical stages, because it resulted in long survival with low toxicity.

Increased O6-methylguanine-DNA methyltransferase activity and reduced mutability in 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2- chloroethyl)-3-nitrosourea-resistant HeLa S3 cells

To clarify the involvement of O6-methylguanine (O6-MeG) in mutagenesis, we have been trying to isolate Mer+ cells from a HeLa S3 Mer- cell line, and to compare the mutation frequencies between the cell lines. We previously isolated the N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-resistant cells, MR10-1, from HeLa S3 Mer- cells. However, the MR10-1 cells still had only a little O6-MeG-DNA methyltransferase (MT) activity. In the present study, we have isolated two 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU)-resistant cells, ACr41 and ACr42, from the MR10-1 cells. The two ACr cells had increased MT activities. The ACr cells were also significantly more resistant to 1-(2-chloroethyl)-1-nitrosourea and slightly more resistant to MNNG than the MR10-1 cells. When the mutation frequencies were tested at the hypoxanthine-guanine phosphoribosyl transferase and ouabain loci in these cell lines, the two ACr cells were more resistant to the mutagenic effect of MNNG than the MR10-1 cells. These results show the linkage between the resistance to the cytotoxic effect of nitrosourea compounds and MT activity, and strongly support the hypothesis that O6-MeG is the main pre-mutagenic lesion induced by MNNG.

[Mechanisms of cellular resistance to chloroethylnitrosourea in cell lines derived from human brain tumors]

The cytotoxic and cytogenetic effects 1-(4-amino-2-methyl 1-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and 1, 3-bis (2-chloroethyl)-1-nitrosourea (BCNU) treatments on five cell lines derived from human malignant glioma were studied. Compared to sensitive cell line SF-126, SF-188 cells were 3- to 6.9 fold more resistant to the cytotoxic effect and 8 to 14 fold more resistant to the induction of sister chromatid exchanges (SCEs). Cytotoxic effects and induction of SCEs were intermediate for SF-268, SF-210 and SF-295 cell lines compared with SF-126 and SF-188. There was a good correlation between susceptibility to the cytotoxic effects and formation of DNA interstrand crosslinks for cells treated with ACNU and BCNU. The effects of cis-diamminedichloroplatinum (II) (cis-Pt) and nitrogen mustard (HN2) in these cells were also studied. Cis-Pt was equally cytotoxic and induced the same number of SCEs and DNA interstrand cross-links in all five cel lines. In contrast to the results obtained by treatment with chloroethylnitrosoureas (CENUs), SF-126 cells treated with HN2 were more resistant to the cytotoxic effects, the induction of SCEs, and the induction of DNA interstrand cross-links than were SF-188 cells. The repair of O6-methylguanine after treatment of these cell lines with (3H) methylnitrosourea were quantitated. SF-126 cells showed no detectable repair of O6-methylguanine, SF-268, SF-210 and SF-295 cells had intermediate levels of repair, and SF-188 had very high level of repair. These results suggest that cellular resistance to CENUs dose not result in cross-resistance to HN2 or cis-Pt, and that one of mechanisms of cellular resistance to CENUs is increased repair of O6-alkylguanine derivatives in DNA, which prevents DNA interstrand cross-links and then reduces both cytotoxic effects and the induction of SCEs in cell resistant to CENUs.

Cell killing action of cell cycle phase-non-specific antitumor agents is dependent on concentration--time product

Based on a pharmacokinetic model proposed by Jusko, which assumes that the cell killing action of cell cycle phase-non-specific agents occurs as a bimolecular reaction depending on drug concentration and cell density, we derived a cell kill kinetic equation for these drugs, including the decomposition constant in culture medium. This equation revealed that the cell killing activity of these drugs depends on the value of concentration x exposure time or the area under the drug concentration--time curve (AUC). It was also clarified that the curves for concentration--exposure time necessary for 90% cell kill on a log scale simulated on the basis of the equation differ according as whether drugs are stable or unstable in the culture medium, being expected to be linear with a slope of -1 in the former case, and to take the form of an asymptotic curve in the latter. For three cell cycle phase-non-specific agents, mitomycin C (MMC), 1-(4-amino-2-methylpyrimidine-5-yl)-methyl-3-(2-chloroethyl)3-nitrosoure a hydro-chloride (ACNU), and nitrogen mustard (HN2), we assessed the concentrations necessary for 90% cell kill (IC90) with various exposure times and the degradation rate constants under the culture conditions used. MMC was quite stable during the incubation, while ACNU and HN2 were unstable. When IC90's and exposure times were plotted on the above-mentioned graph, a linear relationship with a slope of -1 was seen for MMC, while for ACNU and HN2 the anticipated asymptotic curves resulted. We also ascertained that the decomposition constants for ACNU and HN2 expected on the basis of these curves showed a good agreement with the corresponding experimentally observed values. These results indicate that the cell killing action of cell cycle phase-non-specific drugs can be well described by a pharmacodynamic model and equation employing their decomposition constants and are dependent on the concentration-time product.

Preliminary experimental results with the nitrosourea derivative ACNU in the treatment of malignant gliomas

Comparative studies were carried out to evaluate the cytotoxic effectiveness of the nitrosureas ACNU (Nimustine) and BCNU (Carmustine) at equitoxic dose levels in xenografts from two astrocytomas grades III/IV (Li, Re) and one oligodendroglioma grade III (Oe) on nude mice. Growth delay was measured as the endpoint. All tumours were characterized initially and at regular intervals in later passages as to their histomorphologic pattern, expression of glial fibrillary acid protein and DNA-content by means of flow cytometry. These characteristics were shown to be unchanged in our xenografts over more than 27 passages. Growth delays of 18.7 days (ACNU) and 2.4 days (BCNU) for the Li-xenograft (p less than 0.01) were observed at an LD10 for both drugs. For the Re- and Oe-xenografts, growth delays of 18.0 vs. 14.0 days (p less than 0.001) and greater than 27.0 vs. 14.2 days (p less than 0.02) were observed at an equitoxic dose of 33 mg/kg ACNU or BCNU i.p., respectively. These preclinical data suggest a therapeutic advantage with ACNU for these high grade gliomas and should encourage further experimental and clinical investigations.

Pharmacokinetic approach to rational therapeutic doses for human tumor-bearing nude mice

To improve clinical predictability from therapeutic results of various antitumor agents in human tumor/nude mouse models it seems to be important to use a dose pharmacokinetically equivalent to the clinical dose. Thus, we attempted to find the dose of a given drug that can reproduce in the nude mouse a plasma level similar to that seen in human patients treated with an effective dose of the drug based on comparative pharmacokinetic studies between man and nude mouse. As a result, those of 3 alkylating agents, mitomycin C, 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosourea (ACNU) and cyclophosphamide, and those of 2 antimitotic agents, vincristine and vinblastine, were estimated to be one-fourth or one-fifth of their maximum tolerated doses (MTD's). On the other hand, in the case of adriamycin, its MTD was approximately equivalent to its clinical dose pharmacokinetically. In contrast, clinically equivalent doses of 2 antimetabolites tested, 5-fluorouracil and methotrexate, were significantly greater than their MTD's; i.e., their plasma levels did not reach the effective clinical ones even when their MTD's were administered to the nude mice. These results suggest that the antitumor effects of most antitumor agents are over- or underestimated in this model when MTD's are used as a therapeutic dose, and indicate that the use of clinically equivalent doses determined pharmacokinetically is desirable.

[Randomized comparative study of CE (CDDP plus etoposide) and CE-AVN (ACNU, VCR plus procarbazine) as combined anticancer chemotherapy in small cell cancer of the lung]

A randomized comparative study of anticancer chemotherapy CE (CDDP plus etoposide) and CE-AVN (ACNU, VCR plus procarbazine) was carried out on 27 patients with small cell lung cancer (SCLC) without previous chemotherapy. In CE therapy, 12 patients received injection of CDDP (80 mg/m2 on day 1) and etoposide (75 mg/m2 on day 1-5) every 4 weeks (Protocol 1). Fifteen patients received 2 courses of CE and 1 course of AVN therapy (ACNU 100 mg/m2 on day 1, vincristine 0.7 mg/m2 once a week and procarbazine 50 mg/day, daily) for 6 to 8 weeks (Protocol 2). One patient (8%) and 2 patients (20%) achieved complete response with Protocol 1 and 2, respectively. Seven patients (58%) and 9 patients (60%) achieved partial response with Protocol 1 and 2, respectively. The median survival time (MST) was 12 and 14 months, and duration of remission was 4.5 and 7 months in patients treated with Protocol 1 and 2, respectively. No significant difference in MST and duration of remission in each group was observed. However, 2 patients (13%) treated with Protocol 2 survived more than 3 years. Both protocols were well tolerated with only moderate gastrointestinal symptoms, mild bone marrow toxicity and alopecia.

Responsiveness of human gastric tumors implanted in nude mice to clinically equivalent doses of various antitumor agents

To reproduce clinical effects of various antitumor agents in the human tumor/nude mouse model, we investigated the responsiveness of 11 lines of human gastric tumor xenografts to doses of the agents pharmacokinetically equivalent to the respective clinical doses, which we designated the "rational dose" (RD). We found that the response rates to mitomycin C, 3-[(4-amino-2-methyl-5-pyrimidinyl]methyl-1-[2-chloroethyl]-1- nitrosourea (ACNU), adriamycin, 5-fluorouracil were 18%, and that to vinblastine was 30%; on the other hand, those to vincristine, methotrexate, and cyclophosphamide were poor. In contrast, in our previous study using the maximum tolerated doses, response rates to mitomycin C, ACNU, and vinblastine were as high as 64-82%, and those to adriamycin and 5-fluorouracil were 18%. When these results were compared with the clinical response rates of gastric tumors, as a whole, the results with RD's exhibited much better coincidence with the clinical data in terms of relative therapeutic potency, indicating the validity of the use of clinically equivalent doses instead of maximum tolerated doses in the human tumor model.

[Response to antitumor agents of human transplantable glioma implanted into chorioallantoic membrane of chick embryo]

In case of chemotherapy against brain tumors, it is most important to choose suitable drugs for brain tumors, since human tumors have different drug sensitivity and growth. Heretofore, the nitrosourea-induced rat glioma cell, such as C6, or immunodeficient mice were usually used for predicting the drug sensitivity of brain tumors. We took notice of Murphy's system for the chemosensitivity test, in which a human tumor is transplanted into the chorioallantoic membrane (CAM) of a chick embryo. By modifying the conventional Murphy's system, we studied the efficiency of this system in predicting the drug sensitivity of brain tumors. First, we compared the result of a drug sensitivity test using CAM of a chick embryo with that using nude mice. Next we studied the effect of chemotherapeutic agents against brain metastasis of a chick embryo caused by the intravenous injection of mouse B16 melanoma cells. The tumor reduction rate of the sensitivity test using a chick embryo tended to agree with that using nude mice. In the drug sensitivity test against brain metastasis, ACNU was the most effective. This result supports the result of the clinical study. In conclusion, the drug sensitivity test using a chick embryo is thought to be useful and the advantages or disadvantages of this system are discussed.

[The role of radiotherapy in small cell lung cancer]

From 1974 to 1984, we have treated 70 patients with SCLC using radiotherapy (RT) alone or in combination with chemotherapy (CT). It was demonstrated that a heavy CT regimen causing a severe toxicity did not always cause good results. On the other hand, there was a long-term survivor in those patients who were treated with RT alone. Considering from our results as well as from reviews of literatures, it is evident that RT can reduce a significant number of local relapses but has little effect on systemic disease. Therefore, RT added to CT seems to improve a long-term survival specifically in those patients in whom CR is induced from CT. The characteristics of the long-term survivors treated with combined treatment are: limited disease, thoracic RT, good PS, only single site of metastases. In conclusion, there is no doubt that CT plays an important role in the management of SCLC. However, its efficacy is still far from desired, and a new type of CT is warranted.

Immunogenic potential of tumor cells after treatment with antitumor chemotherapeutic agents

Mouse EL-4 lymphoma cells exposed in vitro for short periods to 4-hydroperoxycyclophosphamide, an in vitro active derivative of cyclophosphamide, and to another alkylating agent, cis-diamminedichloroplatinum(II), as well as to mitomycin C, induced development of antitumor immunity in syngeneic mice co-administered with OK-432, an immunostimulator prepared from streptococci. The anthracyclines (adriamycin and daunomycin) were very slightly effective. The efficacy of the alkylating agents in inducing tumor immunity was also demonstrated by their ability to stimulate secondary in vitro generation of splenic cytotoxicity. These data supported the proposed explanation for effectiveness of chemoimmunotherapy against poorly immunogenic tumors.

[Induction and intensive combined therapy of acute myeloid leukemia in adults]

In a prospective multicenter study the efficacy and toxicity of an induction therapy with daunorubicin, cytosine-arabinoside and VP 16-213, followed by an intensified consolidation with high-dose cytosine-arabinoside and daunorubicin, is evaluated in adult patients with acute myelogenous leukemia. The upper age limit for inclusion in the study was 50 years. Within the first two years of this study 91 patients were enrolled. In 84 patients who have finished the remission induction therapy the rate of complete remissions is 67%. The median survival time of all patients is 22 months and the probability of survival is 46% after 24 months. So far 34 patients in complete remission have been given one or two courses of the intensified consolidation therapy with high-dose cytosine-arabinoside and daunorubicin. The probability of relapse-free survival in these patients is 46% after 22 months and the median remission duration is 20 months.

[Analysis of DNA damage induced by nitrosourea derivatives in rat brain tumor cells using a sequencing procedure]

DNA damages caused by various anticancer nitrosourea compounds such as ACNU and MCNU were studied. Reiterated fragments of 167 and 203 base pairs (bp) were obtained after Hind III and Hae III restriction endonuclease digestion of 9L rat brain tumor DNA. The end-labeled reiterated fragments were reacted with ACNU and MCNU, which resulted in the scission breaks corresponding to the locations of guanine on an extended Maxam-Gilbert sequencing gel. Subsequent piperidine hydrolysis yielded scission products more frequently. These results indicate that nitrosoureas such as ACNU and MCNU generate DNA scission breaks and/or alkali-labile sites preferentially at the position of guanine moieties in rat brain tumor DNA.

Carcinogenicity of 1-(4-amino-2-methylpyrimidine-5-yl)-methyl-3-(2-chloroethyl)-3- nitrosoureahydrochloride and three related N-nitroso derivatives following repeated intravenous administration to male Wistar rats

Long-term toxic evaluation of 1-(4-amino-2-methylpyrimidine-5-yl)-methyl-3- (2-chloroethyl)-3-nitrosoureahydrochloride (ACNU), 1-(2-chloroethyl)-1-nitroso-3-(methylene-2-pyridylium)-urea- hydrochloride (CNMPU), 1-(2-chloroethyl)-1-nitroso-3-(4-thiomorpholino)-urea (CNTMU) and 4-[N-(2-chloroethyl)-N-nitrosocarbamoyl]-morpholine (CNCM) which were administered each at five dosages, adapted to the clinical situation, revealed significantly increased tumor risks for the first three agents in the lung and the adrenal gland. Additionally, CNTMU and ACNU induced a significant rise in the tumor load of the neurogenic tissue; the latter compound, being in clinical use, was associated with a significantly increased number of mammary tumors as well. CNCM, however, did not exhibit significantly elevated carcinogenic activity, although the overall tumor load was up to 2.4-fold increased compared to controls. The results indicate no advantage of the newly developed ACNU with respect to its inherent carcinogenic risk as compared to clinically established 2-chloroethyl-N-nitroso derivatives.

[UFT + MMC and UFT + ACNU therapy in advanced gastric cancer]

The effects of UFT + MMC and UFT + ACNU therapy on advanced gastric cancer were compared by randomized controlled trial in 12 institutions. Unresectable and postoperatively recurrent patients were divided into PS 0-2 and 3-4 groups. After classification according to cancer spread, such as localized type, hepatic metastatic type, ascitic type and distant metastatic type, regimens of (A) UFT 375 mg/m2/day + MMC 5 mg/m2 for 1-2 W or (B) UFT + ACNU 60 mg/m2/W/x2 (with a 4-week interval) were administered for as long as possible. As a result, among a total of 104 cases, responses were recognized in 7 out of 32 cases (21.9%) treated with regimen A and in 5 out of 25 cases (20.0%) treated with regimen B, giving a total of 57 evaluable cases excluding 33 incompletely evaluated cases and 14 ineligible cases. This study therefore demonstrated no significant difference between the two regimens. The median survival of patients treated with regimen A was 120 days, and that of patients treated with regimen B, 155 days. There was no significant difference between the two regimens. As side effects, UGI symptoms were recognized in 35.4% of regimen A patients and in 37.1% of regimen B patients. Bone marrow suppression appeared in 39.6% of regimen A patients and in 54.3% of regimen B patients.

Protective effect of nimustine hydrochloride against radiation-induced pulmonary injury in mice

Female C3H/HeN mice were irradiated in the thorax at a dose ranging from 10 to 25 Gy with or without ACNU (nimustine hydrochloride) treatment in order to determine whether the chemotherapeutic agent would lead to an enhancement of radiation-induced lung damage. ACNU given intravenously at 15 mg/kg immediately prior to irradiation reduced the mortality of mice irradiated with a low dose; mortality with either radiation alone or radiation plus ACNU was 4/10 (40%) or 0/10 (0%) at 13.1 Gy, and 9/10 (90%) or 6/10 (60%) at 15 Gy, respectively. The presence of ACNU during thoracic irradiation also prolonged the survival time of mice approximately 2-fold over that of animals given radiation alone. Histological examination of mice sacrificed 80 days after treatments revealed that the combination of drug and irradiation produced no radiation pneumonitis, which was predominant in mice given radiation alone. It is unexpectedly concluded that ACNU may have a protective effect against radiation-induced lung injury.

Detection of DNA sites damaged by 1-(4-amino-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) using a DNA sequencing procedure

A DNA sequencing technique was applied to the highly reiterated DNA from HeLa S3 cells in order to detect DNA damage induced by the antitumor drug, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU). A DNA reiterated fragment of 92 base pairs (bp) was isolated by gel electrophoresis after EcoRI and EcoRI restriction endonuclease digestion. In the defined sequence of the 92 bp fragment, ACNU caused damage and modifications primarily at guanine moieties, leading to alkali-labile sites as determined by subsequent piperidine reaction on an extended Maxam-Gilbert sequencing gel. These results indicate that guanine moieties in double-stranded DNA are preferentially vulnerable to ACNU over other base moieties.

O6-methylguanine methyltransferase activity and sensitivity of Japanese tumor cell strains to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)- 3-nitrosourea hydrochloride

Using 40 tumor cell strains derived from various organs of Japanese tumor patients and also 12 normal cell strains, we have measured the activity of O6-methylguanine-DNA methyltransferase (MT), which can repair O6-methylguanine produced in DNA by alkylating agents. Then, the lethal sensitivities of the strains to the anti-tumor drug 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-)2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) were measured. The MT activity was assayed by measuring the 3H radioactivity transferred from the substrate DNA containing [methyl-3H]-O6-methylguanine to acceptor molecules in the cell extracts. Extracts from the majority of tumor strains and all normal cell strains contained substantial MT activity of varying degree, while the extracts of 6 tumor strains showed virtually undetectable MT activity. Hence these 6 strains were assigned as Mer-, the phenotype which is characterized by the inability to repair O6-methylguanine in DNA due to the lack of MT. The Mer- tumor strains were much more sensitive to ACNU than the rest of Mer+ strains, as measured by colony-forming ability. Furthermore, with all the tumor and normal strains tested, a good correlation was observed between MT activity and cellular resistance to ACNU. These results indicate that the frequency of Mer- strain is about 15% among Japanese tumor cell strains so far analyzed, and further suggest that MT may be the only system able to repair lethal DNA damage induced by ACNU.

Experimental combination chemotherapy of ACNU and 5-FU against cultured glioma model (spheroid) and subcutaneous rat glioma

The effects of combination chemotherapy of ACNU and 5-FU on cells grown exponentially as monolayers, cells in multi-cell spheroids and in s.c. transplanted tumors of rat glioma clone-6 cells were analyzed by the colony-forming assay. The cytotoxic effect of ACNU on cells in spheroids was enhanced by continuous 5-FU pretreatment for several hours, but further enhancement was obtained only if the 5-FU pretreatment lasted for more than 12 hr. The combined effect was decreased by a drug-free interval due to recovery from potentially lethal 5-FU damage, but ACNU treatment immediately after 5-FU treatment suppressed PLD recovery. Analysis with sequential trypsinization of spheroids indicated that ACNU showed more marked cytotoxicity on cells in the deeper layers in spheroids than on those in the outer layers, whereas the effect of 5-FU decreased towards the deeper cell layers. Enhancement of treatment with ACNU combined with 5-FU was evident for cells in the outer layers, but was more remarkable in the deeper layers. The combined effect of ACNU and 5-FU on s.c. tumors was similar to that in spheroids. The effect of combined treatment of ACNU with 5-FU on increase in body weight was within the additive range of both drugs acting independently, but was more than additive for the growth delay of s.c. tumors.

Specific induction of ACNU-resistance in V79 Chinese hamster cells and C6 rat glioma cells

The antitumor compound ACNU (1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride) is widely used for treatment of malignant brain tumors. The authors have investigated the mechanism of acquisition of ACNU resistance at the cellular level by isolating ACNU-resistant mutants from V79 Chinese hamster cells and C6 rat glioma cells after treatment of the cells with ACNU or other alkylating agents. In V79 Chinese hamster cells, ACNU at 1 to 4 micrograms/ml caused dose-dependent induction of drug-resistant mutants to ACNU (10 micrograms/ml) and 8-azaguanine (20 micrograms/ml), but not to ouabain (1 mM). Values for the mean lethal dose of ACNU-resistant mutants were 2.4 to 17.2 times those of the parent V79 cells. The ACNU-resistant phenotype was stable during an observation period of 13 weeks. The ACNU seemed to have a specific effect in inducing ACNU-resistant mutations, because no ACNU-resistant mutations were induced by treatment of the cells with other known mutagens, such as N-methyl-N'-nitro-N-nitrosoguanidine, methylmethanesulfonate, and ethylmethanesulfonate. The C6 rat glioma cells also showed a significant mutagenic response to ACNU, producing ACNU- and 5-fluorouracil-resistant mutants. The present results have the important therapeutic and mechanistic implication that ACNU is a potent mutagen and induces mutants that are resistant to ACNU and to other drugs.

Acquisition of resistance to 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride in V79 cells through increased removal of O6-alkylguanine

The molecular mechanism of acquisition of resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride (ACNU) was investigated using ACNU-resistant clones (ACNUr-1-4) isolated from the V79 cell line. The binding level of alkyl cyanate, a decomposition product of ACNU, to protein in ACNUr-1 cells was not less than that in the parental V79 cells, indicating that the acquired resistance was not due to a reduced intracellular concentration of ACNU. Because O6-chloroethylguanine, an intermediate in cytotoxic interstrand cross-link formation by ACNU, is known to be repaired by the same mechanism as O6-ethyldeoxyguanosine (O6-EtdGuo), we quantitated O6-EtdGuo by radioimmunoassay at various times after exposure of cells to 100 micrograms/ml N-ethyl-N-nitrosourea for 20 min. In V79 cells, elimination of O6-EtdGuo was negligible, but in all four resistant clones, 30 to 59% of the O6-EtdGuo was removed within 24 hr after exposure. This increased removal of O6-EtdGuo among the resistant clones was associated with the activity of O6-alkylguanine DNA alkyltransferase (O6-AGT) determined using cell extracts. The present results indicate that increased removal of O6-chloroethylguanine in ACNU-resistant clones by O6-AGT is mechanistically linked to the acquisition of resistance to ACNU.

The mechanism and overcoming of resistance in ACNU-resistant sublines of C6 and 9L rat glioma

In order to study the mechanism of the resistance to chemotherapeutic agents, especially ACNU [1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride), two variant cell lines (C6/ACNU and 9L/ACNU) resistant to ACNU were selected in vivo from rat C6 and 9L glioma, respectively. Uptake and efflux of ACNU in these resistant cells were studied with Ethylene[14C]ACNU. The result indicated that the resistance exhibited by both sublines were due to both the reduced uptake of the drug and the increased efflux. The study of the effects of oxidative phosphorylation inhibitor, DNP (2,4-dinitrophenol), on the uptake and retention of ACNU suggested that there is an active outward transport mechanism for ACNU in both glioma sublines and that enhanced activity of this efflux mechanism renders cells highly resistant to the cytotoxic action of ACNU. In an attempt to clarify the more detailed biochemical mechanisms of this active efflux system, we surveyed various membrane-modifying agents which potentiate the sensitivity of these resistant cells to ACNU. Among a number of membrane-modifying agents, reserpine was found to retain ACNU in the resistant cells and to enhance the action of ACNU on these resistant cell lines. It may be concluded that drugs such as reserpine may overcome a mechanism of ACNU resistance.

Comparative analysis of O6-methylguanine methyltransferase activity and cellular sensitivity to alkylating agents in cell strains derived from a variety of animal species

Using 26 cultured cell lines derived from 17 different animal species, we have measured both the activity of O6-methylguanine (O6-MeG) methyltransferase (MT) in cell extracts and the sensitivity of the strains to the lethal effects of the alkylating agents, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU). The MT activity was assayed by measuring the amount of 3H radioactivity transferred from methyl-[3H]-labeled O6-MeG in DNA to acceptor protein molecules in the extracts. In all the 21 mammalian cell strains, lethal sensitivity to ACNU as measured by colony-forming ability correlated well with cellular MT activity, indicating that the major lethal ACNU damage is reparable by the MT. On the other hand, MNNG sensitivity did not necessarily correlate with the MT activity.

Intracarotid infusion of ACNU and BCNU as adjuvant therapy of malignant gliomas. Clinical aspects and critical considerations

Thirty patients with malignant gliomas were treated by operation, radiotherapy and additional intracarotid infusions of ACNU and BCNU. Positive results were obtained in the treatment of oligodendrogliomas and astrocytomas grade III and IV. On the contrary, the results in cases of glioblastoma multiforme were disappointing: neither survival time nor quality of life had been significantly improved. The protective effect of phenobarbitone against systemic toxicity by ACNU was not always confirmed in this study. Based on literature reports and our own experience the indications, technical aspects, unexpected complications and results of this therapeutic approach are discussed.

[An autopsy case of neurocutaneous melanosis associated with intracerebral malignant melanoma]

The authors reported the clinical course and the postmortem examination of a unique case of neurocutaneous melanosis with numerous anomalies and complications, which included congenital dislocation of lenses, hypogonadism, ectopia of prostatic duct, genuine phimose, retentio testis, psina bifida and neurogenic bladder. This 13-year-old boy with a large hairy nevus in a bathing trunk configulation and multiple small nevi over the whole body since his birth was admitted to our hospital for evaluation of headache and vomiting. Neurological examination showed bilateral papilledema and slight left hemiparesis. A CT scan revealed a large right frontal mass and craniotomy was performed with subtotal removal of this tumor which was confirmed as a malignant leptomeningeal melanoma. He initially made uneventful postoperative recovery, and two courses of chemotherapy with DTIC, ACNU and VCR were given; however, the currence of brain tumor ensued shortly thereafter, and he died in approximately six months after the onset of intracranial symptoms despite of the third course of chemotherapy. Thirty five cases of neurocutaneous melanosis associated with or without malignant melanoma have been reported in Japan. Twenty-eight cases were male and 7 female. Two cases showed the evidence of primary malignant melanoma outside of the central nervous system, whereas twenty eight leptomeningeal melanoma, in which 22 were solid and 6 diffuse, were shown intracranially. Other 5 cases had epileptic seizure and/or hydrocephalus caused by wide spreaded leptmeningeal melanosis. This high incidence of intracranial malignant melanoma in this disorder was remarkable compaired with the previous reports in other countries. Mean duration between deaths and the onset of symptoms of intracranial hypertension or focal neurological signs was 7 months, ranging from 1 to 24 months, showing the rapidly deteriorating course in this disorder.(ABSTRACT TRUNCATED AT 250 WORDS)

The prognostic value of response to the first cycle of chemotherapy in small cell lung cancer. Results of a multicenter German trial

The prognostic significance of evaluation of response according to chest X-ray after only one cycle of treatment was investigated in patients with small cell lung cancer (SCLC). Three hundred and six patients entered a multicenter randomized German trial testing alternating vs. sequential chemotherapy. Decrease of tumor size after the first cycle was seen to be 78% in the alternating group and 70% in the sequential group. Stable disease occurred in 25% of the sequentially treated and 19% of the alternatingly treated patients. No substantial differences in pretreatment characteristics were noticed between patients with stable disease in sequential and alternating treatment. In sequential therapy, median survival was 323 days for patients with decrease of tumor size after the first cycle and 219 days for patients with no change. Only five out of 21 patients with no change after one cycle responded to continuous administration of this regimen including one complete remission. In alternating therapy, median survival was 347 days for patients with decrease in tumor size after the first cycle and 378 days for patients with no change indicating no difference in prognosis. Twelve out of 18 patients with no change responded to continuous administration of alternating treatment including six complete remissions. We concluded that response to the first cycle according to chest X-ray is a reliable and prognostically valid response criterion if sequential therapy is used. In this treatment modality no change in tumor size after the first cycle indicates poor prognosis, and improvement of the patients' outcome may be achieved by a switch to a second non-cross resistant drug combination.

Temperature-dependence of cytotoxicity of several genotoxicants in Chinese hamster V79 cells: bleomycin, paraquat, and some N-alkyl-N-nitrosoureas

Chinese hamster V79 cultured cells were treated with bleomycin (BLM), paraquat (PQ), N-methyl-N-nitrosourea (MNU), and ACNU (an anti-cancer agent) at 30-43 degrees C. The survival fractions normalized by those released from heat-death were plotted vs. the integrated doses of the chemical. Arrhenius analysis of the cell inactivation by the chemical was made. The results revealed that BLM and PQ exerted synergistic cytotoxicity with hyperthermia, whereas MNU and ACNU exerted temperature-dependent cytotoxicities obeying the Arrhenius law.

Significance of DNA cross-links on 1-(4-amino-2-methylpyrimidin-5-yl)methyl-3-(2-chloroethyl)-3- nitrosourea (ACNU)-induced cytotoxicity against ACNU-sensitive and -resistant lines of 9L rat glioma cells

The formation and removal of DNA cross-links caused by treatment with 1-(4-amino-2-methylpyrimidin-5-yl)-methyl-3-(2-chloroethyl)-3-nitr osourea (ACNU) were assayed by the technique of alkaline elution for DNA in comparison with the cytotoxicities in ACNU-sensitive rat 9L cells or ACNU-resistant subclones of 9L cells (9L/R cells). The ACNU-resistant 9L/R cells appeared to be about 16 times more resistant against ACNU than were the 9L cells. The DNA cross-links immediately after the treatment with ACNU were not detectable in 9L or 9L/R cells. Although the level of cross-links for 9L cells had reached a maximum at 6 hours and then persisted at almost the same level as that at 24 hours after the treatment with ACNU, the level for 9L/R cells was very low at 6 hours and then gradually decreased at 24 hours after treatment with ACNU. Inhibition of the formation of DNA interstrand cross-links caused by the treatment with ACNU might be a factor for the ACNU resistance in 9L/R cells. Also, the capacity for the repair of DNA interstrand cross-links might participate in the mechanisms of the ACNU resistance in 9L/R cells.

Cell cycle perturbation of cultured C6 glioma cells following short-term contact with a low dose of ACNU

The purpose of this study was to investigate the cell cycle perturbation of cultured C6 rat glioma cells induced by 1-(4-amino-2-methyl-5-pyrimidyl)methyl-3-(2-chloroethyl)3-nitrosourea hydrochloride (ACNU) using simultaneous flow cytometric measurements of DNA and bromodeoxyuridine (BrdU) content. A new graphic computer program permitted the quantification of cell density in hexagonal subareas and allowed the fraction of BrdU-labeled cells with mid-S phase DNA content (FLS) to be defined in a narrow window. The cell kinetic parameters such as cell cycle time (Tc) and S phase time (Ts) were estimated from a manually plotted FLS curve at 18 and 6 hr, respectively. The major effect of ACNU on the cell cycle was an accumulation of the cells in the G2M phase 12 to 24 hr posttreatment when compared to G2M traverse of untreated cells. For the two-dimensional analysis, cells were labeled with BrdU and then treated with ACNU, or treated with ACNU and then labeled with BrdU. It was concluded that the cells in the S and G2M phases at the time of ACNU administration progressed to mitosis but that the G1 phase cells accumulated in the subsequent G2M phase. Two-dimensional FCM analysis using BrdU provided a useful tool in studying cell cycle perturbation.

Effects of combined treatment with nimustine hydrochloride and radiation on solid FM3A tumor in mice

Female C3H/HeN mice bearing solid FM3A tumors were treated with a combination of ACNU (or Nimustine hydrochloride) and radiation in order to investigate the antitumor effects and also to determine the optimal treatment schedule of ACNU in such combined therapy. ACNU was intravenously injected either twice with an interval of 2 weeks and a dose of 30 mg/kg (intermittent large-dose treatment), or as 4 weekly doses of 15 mg/kg (fractionated small-dose treatment). Local irradiation (5 Gy) at the tumor site was performed twice with an interval of 2 weeks between the doses. Synergistic effects were obtained by the combination of ACNU and radiotherapy in terms of tumor growth inhibition and prolongation of survival. Histology also revealed much greater reduction of viable tumor cells in the case of combination treatment. With either treatment with ACNU alone or in combination with irradiation, the intermittent large-dose injections resulted in better inhibition of tumor growth than did the fractionated small-dose injections, but the survival times with the intermittent treatments were not as prolonged as would be expected from the direct effects. Loss of body weight and depression of WBC number were also much more severe in the intermittent treatment group. Thus, it may be concluded that when ACNU is combined with radiotherapy, the intermittent large-dose regimen is not necessarily superior to the fractionated small-dose one.

[Controlled multimodality treatment of brain stem gliomas]

Thirty-eight children were diagnosed as having a brain stem glioma at Nagoya University. Thirty-three patients in our previous series from 1957 to 1983, were treated traditionally with radiation and at late stage with shunting operation for hydrocephalus and/or suboccipital decompression, but not with direct operation for tumors. In general, tumors constantly grew regardless histology and their mean survival time was only 7.0 months even with transient neurological remission. On the other hand, recent five patients since 1984 were treated with prospective multimodality treatment. According to neuroradiological studies by X ray and/or NMR, CT scanning, the brain stem glioma cases were classified into subgroups of intrinsic and exophytic. Then the former were treated non-surgically with adjuvant therapy of Interferon-ACNU-Radiation (IAR) and the latter were treated surgically at first by resection of the tumor followed by adjuvant therapy of IAR or interferon-CDDP. Four out of five patients responded to adjuvant therapy (complete response = 2, partial response = 2, response rate = 80%) and they are all alive after 7-28 months follow-up period. It is concluded from our results that CT scanning can diagnose the accurate location and nature of brain stem gliomas, surgical therapy benefits at least in exophytic cases, and IAR adjuvant therapy may prolong the survival time of patients.

Difference in O6-methylguanine methyltransferase activity among transformed NIH3T3 cell clones

We examined the sensitivity to the lethal effects of methylating agents and the O6-methylguanine methyltransferase (MTR) activities of in vitro transformed NIH3T3 cell clones. The sensitivities to the lethal effects of MNNG were not different among all 49 transformed cell clones examined and do not correlate with the MTR activities. All 8 spontaneously transformed cell clones showed the same sensitivities to ACNU as the parental cell line. 2 of 20 transformants induced by UV or MNNG showed higher sensitivities to the ACNU although the MTR activity was normal. One cell clone transformed by UV was sensitive to ACNU and showed about half MTR activity. 5 of 19 cell clones transformed by oncogenes (Ha-ras or SV40 ori-) were sensitive to the lethal effects of ACNU and showed the low MTR activities, but were not as much sensitive as a Ha-MuSV transformed cell clone, Ha821.

Involvement of cytotoxic T-lymphocytes in the antitumor activity of spergualin against L1210 cells

Spergualin exhibited a strong antitumor effect against L1210(IMC), a tumor cell line which has been maintained in BALB/c X DBA/2 F1 (hereafter called CD2F1) mice in the Institute of Microbial Chemistry. Mice inoculated i.p. with 10(5) cells of L1210(IMC) survived more than 60 days by daily i.p. administration of spergualin for 9 days at 5 mg/kg/day, which was started 1 day after the tumor inoculation. These cured mice rejected a second inoculation of 10(6) cells of L1210(IMC), but they did not reject the inoculation of 10(2) P388 cells. In Winn's tumor neutralization assay and in the 51Cr release assay, the T-cell fraction prepared from the spleens of the cured mice had higher cytotoxic activity against L1210(IMC) than whole spleen cells. The cytotoxic activity of spleen cells was diminished by treatment with anti-Thy-1.2 or anti-Lyt-2.1 antibody and complement. Therefore, the effector cells involved in the immunological rejection should be regarded as cytotoxic T-lymphocytes. The cytotoxic activity of these T-lymphocytes was measured during and after the spergualin administration for 9 days, and high activity was observed from 1 day after the final spergualin administration. The antitumor effect of spergualin against L1210(IMC) was much lower in T-cell-deficient athymic mice. These results suggest that cytotoxic T-lymphocytes are involved in the antitumor action of spergualin against L1210(IMC) in vivo.

[Experimental studies on the treatment of recurrent gliomas]

For the purpose to study reasonable treatment for recurrent gliomas, in vitro immunochemosensitivity tests were performed by using human malignant glioma cell line (ONS-12) and its ACNU-resistant cell line (ONS-12/ACNU), which were established in our laboratory. ONS-12/ACNU cells showed a cross-resistance to Ara-C, but not for cisplatin and methotrexate. The lymphokine-activated killer (LAK) cells induced in vitro from the peripheral blood lymphocytes (PBL) of healthy subjects, showed stronger cytotoxicity to ONS-12/ACNU than ONS-12 cells. From these data, selection of appropriate anti-tumor agents on the in vitro sensitivity tests was a most useful method for the treatment of recurrent gliomas, and the adoptive immunotherapy with LAK cells may be useful for ACNU-resistant gliomas.

[Results of supratentorial low-grade astrocytoma--effects of combined radiochemotherapy]

The retrospective analysis of 53 cases with supratentorial low-grade (grade 1 or 2 due to WHO grading) astrocytomas included the years 1965-84. The 5-year and 10-year survival rates were 61.9% and 52.1%, respectively. The recurrence of tumors occurred in 15 cases (28.3%), almost within 3 years after the initial treatment, and early recurrent cases indicated poor results. Among them, 6 cases were noticed increasing malignancy of histological findings. According to our investigations, the factors which influence to the survival rate were age of patients, duration of symptoms before treatment, presence of neurological deficits and degree of surgical removal of tumor. The patients with good prognosis were under 20-year old, over 6 months of duration, with no neurological signs and with total or subtotal removal. But, 5-year survival rate was not so improved by postoperative radiation therapy. Analysis on the effects of chemotherapy for low-grade astrocytoma was little reported. We treated 26 patients with RAFP therapy (Radiation + ACNU + FT-207 + PSK). Only 2 cases out of 26 showed the recurrence till now. The rate of reduction of their tumors was 46.2% by CT scan. So, it was considered that RAFP therapy was effective for supratentorial low-grade astrocytoma.

[Assessment of functional status in children with brain tumors]

Thirty children treated for brain tumors between 1978-1985 at Kurume university hospital were evaluated for alternation in intellectual, emotional, and social function. They were 15 males and 15 females, aged 3 to 16 years, on the averaged 1.7 years after treatment. Twenty-eight children had no neurological deficits and 2 children had slight neurological deficits. It was possible for twenty-eight children to be evaluated for intelligence quotient by Wechsler Intelligence Scale for Children-revised and Tanaka-Binet. The median score and standard deviation of intelligence quotient (IQ) test in children with brain tumors were as follows; verbal IQ: 84 +/- 16, performance IQ: 77 +/- 20, full scale IQ: 80 +/- 20. There children with brain tumors obtained significant low IQ scores than children (t-test, P less than 0.01). Twenty-one (72%) children showed subnormal IQ scores (IQ less than 90) and 7 children showed normal IQ scores (IQ greater than or equal to 90). Concerning social and emotional function, twelve children (45.7%) showed abnormal behaviour. The median scores and standard deviation of IQ scores in cranial irradiated patients were as follows; verbal IQ: 79 +/- 13, performance IQ: 71 +/- 15, full scale IQ: 71 +/- 14. Especially, ten of twelve cranial irradiated patients showed subnormal IQ scores. Also, cranial irradiated patients obtained significant low IQ scores than non-cranial irradiated patients (t-test, P less than 0.05). Serial evaluation of three cranial irradiated patients revealed further deterioration without recurrence of tumor and hydrocephalus, The results are discussed to: (1) the effects and mechanism of cranial irradiation on cognitive development.(ABSTRACT TRUNCATED AT 250 WORDS)