Clinical outcomes of endoscopic submucosal dissection for esophageal squamous cell carcinoma with esophageal varices: Multicenter retrospective study

OBJECTIVES

Clinical outcomes of endoscopic submucosal dissection (ESD) for esophageal squamous cell carcinoma (ESCC) with esophageal varices (EVs) are obscure. We aimed to elucidate the clinical outcomes of ESD for ESCC with EVs in a multicenter, retrospective study.

METHODS

We established a retrospective cohort of 30 patients with ESCC complicating EVs, who underwent ESD at 11 Japanese institutions. Rates of en bloc resection and R0 resection, procedure time, and adverse events were evaluated as indicators of the feasibility and safety of ESD. Additional treatment, recurrence, and metastasis of the lesions were evaluated as indicators of the long-term efficacy of ESD.

RESULTS

Portal hypertension was caused by cirrhosis, of which alcohol was the most common cause. En bloc resection was achieved in 93.3% and R0 resection in 80.0% of the patients. The median procedure time was 92 min. Adverse events included a case of uncontrolled intraoperative bleeding leading to discontinuation of ESD and a case of esophageal stricture due to extensive resection. During the follow-up period of a median for 42 months, a patient with local recurrence and another patient with liver metastasis were observed. One patient died of liver failure after receiving chemoradiotherapy as an additional treatment after ESD. No patient died of ESCC.

CONCLUSION

This multicenter, retrospective cohort study demonstrated the safety and efficacy of ESD for ESCC with EVs. Further studies are needed to establish appropriate treatment methods for EVs before ESD and additional treatments for patients with insufficient ESD.

Helicobacter pylori Eradication Does Not Adversely Affect the Clinical Course of Gastric Cancer: A Multicenter Study on Screening Endoscopic Examination in Japan

BACKGROUND

Since gastric cancers (GCs) detected after Helicobacter pylori (HP) eradication present with different morphological characteristics from conventional HP-positive GCs, delayed detection of early-stage GCs may be observed. This study aimed to investigate the clinical impact of HP eradication on diagnosing GC during screening endoscopy.

METHODS

Eleven health checkup institutions in Japan participated in the present study. All GC cases newly diagnosed by screening endoscopy between January 2016 and December 2020 were included. After propensity score matching, multivariable regression analysis was performed to estimate the effect of HP eradication on deep tumor invasion among HP-eradicated and HP-positive GC cases.

RESULTS

A total of 231 patients with GCs (134 HP-eradicated and 97 HP-positive cases) were enrolled. After propensity score matching, there were 81 cases in each group. The distribution of the depth of tumor invasion (pT1a, pT1b1, pT1b2, and pT2) between the HP-eradicated group and HP-positive group was similar (p = 0.82). In the propensity analysis, with HP-positive as the reference value, HP eradication was not significantly associated with T1b-T4-GCs and T1b2-T4-GCs, with odds ratios (95% confidence intervals) of 1.16 (0.48-2.81) and 1.16 (0.42-3.19), respectively.

CONCLUSIONS

HP eradication does not adversely affect the clinical course of GCs, supporting the recommendation of HP eradication in screening programs to reduce the total number of GC cases without delaying diagnosis.

Feasibility of Endoscopic Screening for Upper Gastrointestinal Malignancy in a Comprehensive Health Checkup

Objective In an effort to reduce mortality from gastric cancer, endoscopic screening was introduced in 2016 as a nationwide screening program in Japan. Recent developments in high-definition endoscopic imaging and diagnostic strategies have enabled the simultaneous detection of other upper gastrointestinal (U-GI) malignancies. Therefore, we conducted a study to evaluate the feasibility of endoscopic screening for U-GI malignancy in a comprehensive health checkup. Methods We retrospectively reviewed the data of 13,120 participants who had received a comprehensive health checkup in a single institution between April 2012 and March 2018. Participants were divided into two groups [gastrointestinal endoscopy (GIE) group (n=9,142) and gastrointestinal X-ray (X-ray) group (n=3,978)] and compared with regards to the screening results, adverse events, and detection rate of U-GI malignancies (gastric cancer or other) using a propensity-score matched analysis. Results The gastric cancer detection rate was significantly higher in the GIE group [34/9,142 (0.48%)] than in the X-ray group [3/3,978 (0.08%)] (p=0.003). Other U-GI malignancies were found only in the GIE group and comprised two hypopharyngeal cancers, five esophageal cancers, two duodenal cancers, and one duodenal gastrointestinal stromal tumor. Adverse events occurred in 6/9,142 (0.07%) participants in the GIE group and 18/3,978 (0.45%) participants in the X-ray group (p<0.0001). A propensity-score matched analysis yielded 1,551 matched pairs, and the detection rate of gastric cancer and other U-GI malignancies remained significantly higher in the GIE group than in the X-ray group. Conclusion This study indicated that not only gastric cancer but also other U-GI malignancies can be detected by endoscopic screening.

Feasibility of gastric endoscopic submucosal dissection without using proton pump inhibitor injection: a propensity score analysis

Purpose: Endoscopic submucosal dissection is a promising method for the resection of superficial gastric neoplasms. To date, several institutions have used proton pump inhibitor injections over the perioperative period. However, there is very little evidence regarding their efficacy. To overcome this limitation, we compared procedural outcomes and the prevention of adverse events of proton pump inhibitor injection with an orally administered active potassium-competitive acid blocker alone. Participants and Methods: We enrolled a total of 150 patients treated for superficial gastric neoplasms at a single institution between April 2015 and December 2018. Patients treated for 2 days with proton pump inhibitor injections following 12 days of oral potassium-competitive acid blocker (proton pump inhibitor group=80) were compared with patients treated for 14 days orally with potassium-competitive acid blocker alone (potassium-competitive acid blocker group=70) using propensity score analysis. We evaluated intragastric pH levels prior to endoscopic submucosal dissection, frequency of intraoperative major bleeding, procedure time, en bloc resection rate, curability, ulcer reduction rate 14 days after endoscopic submucosal dissection, and adverse events (including perforation and postoperative bleeding). Results: Propensity score analysis yielded 43 matched pairs. The comparison demonstrated similar values for the outcomes. For all cases, we observed intragastric pH levels >6.4 prior to endoscopic submucosal dissection. Postoperative bleeding rates were 2.3% (1/43) in the proton pump inhibitor group and 0.0% (0/43) in the potassium-competitive acid blocker group (P=0.315). Conclusions: Oral potassium-competitive acid blocker alone was as effective as proton pump inhibitor injection, with a low incidence of adverse events. Based on these results, proton pump inhibitor injection might be omitted during gastric endoscopic submucosal dissection.

Hemorrhage control during gastric endoscopic submucosal dissection: Techniques using uncovered knives

Since the last decade, endoscopic submucosal dissection (ESD) has been used as the standard treatment for superficial gastrointestinal neoplasms. Trainees learning ESD frequently encounter difficulties such as vascularity, peristalsis, and fibrosis during the procedure. Because individual vascularity differs, it generally cannot be consistently avoided. Given that massive hemorrhages can prolong the procedure time and diminish treatment efficacy and that insufficient vessel handling may also increase postoperative bleeding, hemorrhage control during ESD becomes important to ensure procedure safety. This article discusses methods for controlling hemorrhage during gastric ESD. Endoscopists should have a basic understanding of the vascular architecture and the high‐density areas in blood vessels, which are susceptible to intraoperative hemorrhage. Efficient preventative coagulation should be performed in addition to mastering the techniques for hemorrhage control using hemostatic forceps. Techniques useful for preventing intraoperative hemorrhage at every step (e.g. submucosal injection, mucosal incision, and dissection) should be learned. Gaining procedural competence and learning hemorrhage control techniques not only during ESD but also in daily work would help provide safe and effective treatment.

Effect of Continued Administration of Low-dose Aspirin for Intraoperative Bleeding Control in Gastric Endoscopic Submucosal Dissection

BACKGROUND

The use of antithrombotic agents for the prevention of cerebro-cardioembolic events has increased, and recent guidelines have recommended the continued administration of low-dose aspirin (LDA) during endoscopic procedures with a high risk of bleeding. However, the influence of LDA on intraoperative bleeding control status during Endoscopic submucosal dissection (ESD) remains unclear.

METHODS

We examined 293 consecutive patients who underwent ESD for gastric cancers between January 2014 and February 2018. Patients administered with LDA (n = 52) were compared with those without antithrombotic therapy (n = 241; control) by propensity-score matching (PSM) concerning outcomes of ESD.

RESULTS

PSM analysis yielded 50 matched pairs. Comparison showed similar values for frequency of intraoperative major bleeding: 1 (0-4) times (median [range]) in the LDA group and 0 (0-5) in the control group respectively (p = 0.710). Others (frequency of preventive coagulation, procedure time, decrease of hemoglobin levels, en bloc resection, complete resection) were the same with a few adverse events including perforation (0%), and thromboembolism (0%). Postoperative bleeding rate was 1.9% in LDA group. Multivariate analysis indicated that location U and circumference on the posterior wall were associated with for multiple major intraoperative bleeding.

CONCLUSION

The study suggests that gastric ESD can be safely accomplished without cessation of LDA.

Short-term efficacy of potassium-competitive acid blocker following gastric endoscopic submucosal dissection: a propensity score analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) is a promising method for the resection of superficial gastric neoplasms. Vonoprazan is a novel potassium-competitive acid blocker (P-CAB) that is currently considered as a potential alternative to proton pump inhibitors (PPIs) for the treatment of acid-related diseases. However, the utility of vonoprazan in ESD-related ulcers is unclear. Therefore, we compared the short-term efficacies of vonoprazan and the PPI lansoprazole in ESD-related ulcer healing during the first two weeks following intervention.

METHODS

This study included 115 superficial gastric neoplasms that were treated by ESD at Hiraka General Hospital between April 2015 and January 2017. Patients treated with P-CAB (20 mg vonoprazan, n = 62) or PPI (30 mg lansoprazole, n = 53) were compared using propensity-score matching analysis. Primary outcome was rate of ulcer reduction at two weeks after ESD. Secondary outcomes were coverage ratio of ulcer base by granulation tissue and incidence of postoperative bleeding.

RESULTS

The rate of ulcer reduction was significantly higher (median [range], 80.6% [67.6%-94.5%] vs. 62.7% [33.4%-85.2%]; p < .0001) and coverage ratio of the ulcer base by granulation tissue was significantly accelerated (median [range], 84.1% [67.7%-95.3%] vs. 61.9% [12.1%-90.1%]; P < 0.0001) in the P-CAB group compared with the PPI group. Postoperative bleeding was not observed in either group.

CONCLUSIONS

P-CAB achieved rapid artificial ulcer healing with promotion of granulation tissue formation. However, conventional PPI with initial intravenous infusion might be sufficient for prevention of postoperative bleeding following gastric ESD.

Feasibility of Knife-Coagulated Cut in Gastric Endoscopic Submucosal Dissection: A Case-Control Study

BACKGROUND/AIMS

Intraoperative bleeding remains a challenge during endoscopic submucosal dissection (ESD). Forceps-coagulated cut (FCC) was found to be effective to reduce this bleeding. However, this involved frequent device replacement, and therefore, knife-coagulated cut (KCC) might ensure an easier and smoother procedure. We aimed to assess the effectiveness of KCC with Flushknife-BT at a super-low-output setting.

METHODS

In this prospective study, we compared the hemostasis condition during ESD in 40 pairs of gastric lesions treated by FCC (Group F) or KCC (Group K). The primary outcome was frequency of major bleeding with an analysis by tumor location. The secondary outcomes included frequency of exchanging devices, procedure time, en bloc resection rate, and adverse event rate.

RESULTS

In terms of the frequency of major bleeding, there was no significant difference between Group F and K (0.95 ± 0.12 vs. 0.88 ± 0.17, p = 0.282). Lesions located on the upper third of the stomach involved repeated hemostasis (p = 0.012). The frequency of exchanging devices was higher in Group F than in Group K (6.95 ± 0.42 vs. 0.88 ± 0.17, p = 0.000). Procedure time was reduced in Group K by 15.6%. Other aspects were the same in both groups.

CONCLUSION

KCC prevented intraoperative bleeding just as FCC did. But it decreased device replacement and saved time and only a low risk was involved. This technique could ensure the conduct of a smooth and safe procedure during gastric ESD. UMIN000017229.

Young persimmon ingestion suppresses lipid oxidation in rats

Persimmon is widely eaten in Asia and the nutritional components of young and mature persimmons differ. Although raw young persimmon has a strong bitter taste and is difficult to eat, the beneficial health effects of young persimmon powder have attracted attention in recent years. Young persimmon has been suggested to have hypolipidemic activity as well as other biological effects. However, there has been little investigation of the beneficial effects of young persimmon. In the present study, we investigated the antioxidative effects of persimmon in an animal study and compared the effects of young persimmon and mature persimmon. Six-week-old male F344 rats were divided into three groups and fed a standard diet, young persimmon diet, or mature persimmon diet for 4 wk. The young persimmon and mature persimmon groups were fed a diet containing 5% (w/w) freeze-dried young or mature persimmon. We analyzed phosphatidylcholine hydroperoxide (PCOOH) levels in the rats as a biomarker of membrane lipid peroxidation. Our study showed that plasma PCOOH levels were significantly lower in the young persimmon group (36.1 ± 28.5 pmol/mL plasma) than in the control group (120 ± 66 pmol/mL plasma). No significant difference was observed between the mature persimmon group (57.3 ± 15.6 pmol/mL plasma) and the control group. It is possible that ascorbic acid and soluble tannin contribute to the difference in the antioxidant effects of young and mature persimmons. These results indicated that intake of young persimmon contributes to the reduction of plasma phospholipid hydroperoxide levels in rats.

An autopsy case of intravascular malignant lymphoma presenting with intracranial B-cell type malignant lymphoma

This report concerns a 79-year-old man with intravascular malignant lymphoma who was admitted to our hospital for slight right side hemiparesis. Radiological examinations showed a mass in the left parietal lobe, and a brain biopsy revealed a B-cell type malignant lymphoma. The tumor could not be detected on magnetic resonance images following focal radiotherapy, but the patient died of acute progressive pneumonia about 3 months after the onset of symptoms. An autopsy was performed. Microscopic examinations disclosed proliferation of neoplastic cells in the small and medium-sized blood vessels of the adrenal glands, liver, spleen, pancreas, kidneys and epididymis. A diagnosis of intravascular malignant lymphoma was established on the bases of these autopsy findings.

[Chondrosarcoma of the skull base associated with fatal intratumoral hemorrhage : report of an autopsy case and review of the literature]

We report a case of intracranial chondrosarcoma of the skull base with fatal intra- and peritumoral hemorrhage. A 75-year-old woman complained of right blepharoptosis and diplopia in 1989. An initial diagnosis of Tolosa-Hunt syndrome was made, and the patient was treated with steroid hormone therapy at a local hospital. Because the symptoms had not been relieved, she was admitted to our hospital. Computed tomography (CT) scan and magnetic resonance (MR) images demonstrated a large mass extending from the right side of the clivus to the parasellar region and petrous apex. The mass was partially calcified and had destroyed the base of the middle cranial fossa. The lesion had homogeneous enhancement with contrast medium. Preoperative diagnosis was chordoma or chondroma. A biopsy of the tumor was made. The pathological diagnosis of biopsy specimen was chondroid chordoma. The patient was followed up but no palliative treatment such as radiotherapy was given. On June 25, 1991, she suffered from cerebral infarction. On June 29, 1993, she died of sudden respiratory failure. Autopsy was performed. It revealed intra- and peritumoral hematoma compressing the medulla oblongata, pons and midbrain. Histologically immature chondroid cells proliferated in a myxoid-rich extracellular matrix. The tumor cells were composed of hyperchromatic nuclei and eosinophilic cytoplasm, but there was no evidence of notochordal differentiation. Compared with biopsy findings, the tumor showed high cellular density. Immunohistochemically, the tumor cells reacted positively for S - 100 protein, vimentin and cytokeratin, but negatively for epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA). In view of these histopathological findings, the diagnosis of low-grade myxoid chondrosarcoma was established. Intratumoral hemorrhage often occurs in malignant brain tumors such as glioblastoma and metastatic brain tumor, but chondroid tumors rarely develop a fatal type of intratumoral hemorrhage. Only 8 cases have been reported in detail to date. We discuss the immunohistochemical features and spontaneous intratumoral hemorrhage of chondrosarcoma.

Distribution of DNA cleavages induced by bleomycin and neocarzinostatin in a defined sequence of rat glioma cells

We have demonstrated the usefulness of a highly reiterated sequence of rat DNA as a probe sequence for evaluating the effect of bleomycin (BLM) and neocarzinostatin (NCS) at the level of individual nucleotides. The 370 base pairs (bp) DNA fragment, purified from rat glioma C6 cells after Hind III digestion, was labeled with 32P at either the 3'- or the 5'-ends and then divided into 167 bp and 203 bp by Hae III. These end-labeled DNA fragments were reacted in vitro with BLM or NCS, and electrophoresed on the denaturating 8% polyacrylamide gels according to Maxam and Gilbert's sequencing protocol. BLM created DNA strand breaks at the guanine-cytosine and guanine-thymine (5'----3') sequences, and NCS cleaved DNA at the position of thymines and adenines. The highly reiterated sequence of rat brain tumor DNA therefore provides adequate knowledge of DNA damages induced by BLM and NCS.

Primary pituitary carcinoma with spinal cord metastasis--case report

The authors report a rare case of non-functioning pituitary carcinoma with spinal cord metastasis. A 37-year-old female presented with a 2-month history of right retro-orbital ache and vomiting. She had a pituitary adenoma removed 3 years prior to admission. Neuroradiologically, a mass lesion was demonstrated in the right middle cranial fossa. The tumor was removed through craniotomy and was histologically diagnosed as pituitary carcinoma. One week after the operation, tetraplegia developed and CT scans demonstrated a spinal canal lesion. Although the tumor was removed through C3-C7 laminectomies, she gradually deteriorated and died. At autopsy, a tumor was disclosed in the right temporal lobe and basal ganglia. Moreover, the tumor invaded into the middle cranial fossa and the parasellar region.

Linkage between O6-methylguanine-DNA methyltransferase (O6-MT) activity and cellular resistance to antitumour nitrosoureas in cultured rat brain tumour cell strains

We have examined O6-methylguanine-DNA methyltransferase (O6-MT) activity of rat brain tumour cell strains with reference to cellular resistance to antitumour nitrosoureas, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (nimustine, ACNU) and methyl-6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyrano side (ramustine, MCNU). The values of O6-MT activity were 52 and 160 fmol/mg protein extract in 9L and C6 rat brain tumour cells, respectively; while HeLa S3 cells, as a methyl excision repair positive (Mer+) cell strain, revealed a rather high value of 488 fmol/mg. 9L cells indicative of a low O6-MT activity showed 13 microM for ACNU and 18 microM for MCNU at a 10% survival dose (SD10), determined by a clonogenic cell assay as an index of cellular resistance. In contrast to this, C6 cells revealed a SD10 value of 67 microM and 36 microM for ACNU and MCNU, respectively, indicating higher resistance than 9L cells. HeLa S3 cells showed the highest SD10 value as follows: 84 microM for ACNU and 73 microM for MCNU. The relationship between the O6-MT activity and the cellular resistance was almost linear, with relatively resistant cell lines exhibiting the higher levels of the O6-MT activity. This correlation between the O6-MT activity and the cellular resistance to nitrosoureas as ACNU and MCNU was not observed among other antitumour drugs, which included bleomycin (BLM), neocarzinostatin (NCS), cis-diamminedichloroplatinum (II) (CDDP), and etoposide (VP-16) in clinical use for brain tumour chemotherapy. This indicates that O6-MT activity can be an indicator of cellular resistance to antitumour nitrosoureas in the chemotherapy of brain tumours.

Studies on a new herbicidal antibiotic, homoalanosine

Homoalanosine having a herbicidal activity was isolated from the culture filtrate of a soil isolate SC-1688 which was classified as Streptomyces galilaeus. The chemical structure of homoalanosine was determined to be L-2-amino-4-nitrosohydroxyaminobutyric acid by analyses of spectral and biological data. The antibiotic has high herbicidal activity at low concentrations against especially common cocklebur and ladysthumb among the tested weeds and crops. Foliar application of this antibiotic inhibited the growth of roots and buds. This result indicated that homoalanosine had a systemic herbicidal activity.

[Chemotherapeutic strategy in rat brain tumor cells resistant to ACNU using an in vitro colony formation assay]

Nitrosourea compounds have been widely used in the chemotherapy of malignant brain tumors, because of their blood-brain barrier permeability. However, drug resistance to nitrosoureas has been recently a major concern. Using an in vitro colony formation assay, intrinsic and acquired resistances to an anticancer nitrosourea, 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), were analyzed in rat 9L and C6 glioma cells. 9L and C6 cells were treated with varying doses of ACNU for 2 hours. Ten days after, the cells were fixed and stained with crystal violet. Colonies consisting more than 50 cells were counted. The survival fraction following treatment is the ratios of colony efficiency of treated cells to the colony efficiency of untreated control cells. The dose-response curve for ACNU indicated the existence of a shoulder (Dq, quasithreshold dose) at doses and an exponential cell-killing at higher doses with D0(37% survival dose). Based on dose-response curves corresponding to multitarget single-hit model, 9L cells showed 7.4 microM, 2.9 microM, and 14 microM at Dq, D0, and SD10 (10% survival dose) values, respectively, whereas C6 cells showed respective values of 6.4 microM, 30 microM, and 75 microM. 9L cells had significantly less intrinsic resistance to ACNU than C6 cells at the p less than 0.005 level by a covariance analysis of the curves. As with changes of drug susceptibility after ACNU treatment, both parent cells were treated every other day (1, 5, and 10 repeated times) with various doses up to approximately 1% survival dose of the parent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on new phosphate ester antifungal antibiotics phoslactomycins. I. Taxonomy, fermentation, purification and biological activities

New antibiotics phoslactomycins A, B, C, D, E and F, which contain alpha, beta-unsaturated delta-lactone, phosphate ester, conjugated diene and cyclohexane ring moieties, were isolated from the culture broth of a soil isolate actinomycete. Morphological, cultural and physiological studies revealed that the isolate is a strain of Streptomyces nigrescens. Phoslactomycins were obtained by butanol extraction, gel filtration and reverse phase chromatography. The antibiotics show strong activity against various fungi, particularly phytopathogenic fungi (Botrytis cinerea and Alternaria kikuchiana).

Studies on new phosphate ester antifungal antibiotics phoslactomycins. II. Structure elucidation of phoslactomycins A to F

Phoslactomycins A to F are new antifungal antibiotics produced by Streptomyces nigrescens SC-273. On the basis of physico-chemical properties and NMR studies, their structures have been determined as shown in Fig. 6. They are characterized by possessing alpha, beta-unsaturated delta-lactone, phosphate ester, conjugated diene and cyclohexane ring moieties. The structural difference between them is ascribed to a substituent bound to the cyclohexane ring.

Microspectrofluorometric evaluation of single- and double-stranded DNA in short-term cultured human glioma cells

Seven cerebral gliomas in short-term culture were studied by microspectrofluorometry and acridine orange staining to assess their nuclear content of single- and double-stranded DNA. Benign gliomas showed a diploid DNA pattern, whereas malignant gliomas revealed a higher frequency of DNA aneuploidy and hyperploidy. The content of single-stranded DNA remained relatively low in benign gliomas; however, that in malignant gliomas varied widely. After ACNU treatment, the double-stranded DNA histograms showed S-phase-specific accumulation in all cases but 1 with increasing concentrations of ACNU. The single-stranded DNA content decreased considerably in 2 cases, which responded well to chemotherapy and showed clinical amelioration.

[Circumvention of ACNU-resistance in rat glioma cells by pretreatment with O6-methylguanine]

The chemotherapy of malignant brain tumors has been, only partially successful yet. Recently major concern is drug resistance, one of possible mechanisms of such drug resistance stems from inducible repair enzyme, especially in case of chloroethylnitrosoureas as ACNU or BCNU. We examined the changes of acquired resistance to ACNU in rat glioma cells by pretreatment with O6-methylguanine, which is a substrate for O6-methylguanine methyltransferase. ACNU-resistant (9L/AC) cells had established after 10 times treatments of ACNU. 9L/AC cells were pretreated with 2 mM O6-methylguanine for 2 hours, and subsequently challenged with increasing doses of ACNU for 2 hours. In vitro colony formation assay the survival fraction of 9L and 9L/AC cells ranged from 0.39 to 0.63 by 2-hour reaction of 1-3 mM O6-methylguanine. Based on the dose-response curve for ACNU in 9L/AC cells, by O6-methylguanine pretreatment (2 mM), ACNU-resistance decreased markedly to one-third, one-fifth, and one-two hundredth at 12, 24, 36 microM ACNU, respectively. In contrast, the survival of 9L cells against ACNU was similar under O6-methylguanine pretreatment or nontreatment condition. Therefore, ACNU-resistance is considerably related to DNA repair enzyme induction, and the substrates may potentiate the cell-killing effect of ACNU in the resistant glioma cells.

DNA lability induced by nimustine and ramustine in rat glioma cells

The DNA labile sites induced by two nitrosoureas, nimustine (ACNU) and ramustine (MCNU) synthesised in Japan, have been examined in highly reiterated DNA sequences of rat glioma cells. Reiterated fragments of 167 and 203 base pairs (bp), obtained after Hind III and Hae III restriction endonuclease digestion of rat glioma cells DNA, were used as target DNA sequences to determine the labile sites. In vitro reaction with ACNU and MCNU resulted in scission products corresponding to the locations of guanine. Subsequent piperidine hydrolysis produced more frequent breaks of the phosphodiester bonds at guanine positions, thus forming alkali-labile sites.

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.

[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.

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.

[A case of trigeminal neurinoma with marked extracranial extension]

A case of trigeminal neurinoma with marked extracranial extension is reported with a review of the literature. A 60-year-old female noticed numbness over the left side of the face during the proceeding 15 years. Two years prior to admission, she began to complain of itching and lancinating pain at the left lateral aspect of the nose. Neurologic examination on admission revealed diminished corneal reflex on the left side and hypesthesia in the distribution of the left trigeminal nerve. There was no weakness or atrophy of the ipsilateral masticatory muscles. The remaining cranial nerves and cerebellar functions were normal. Craniograms showed destruction of the left petrous apex, enlargement of the left superior orbital fissure and an extensive bone defect in the floor of the left middle cranial fossa. CT disclosed a huge heterogeneously enhancing mass lesion in the left middle cranial fossa, which extended posteriorly into the left cerebellopontine angle and inferiorly into the pterygoid and infratemporal fossae. Cerebral angiograms revealed medial displacement of the left internal cerebral artery in the ganglionic, cavernous and supraclinoid portions, and elevation of the left middle cerebral artery in the sphenoidal portion. Although the left meningohypophyseal trunk was dilated, no tumor stain was observed. A transantral biopsy specimen provided the diagnosis of neurinoma with Antoni type A tissue. The patient was followed up at the outpatient clinic as radical operations were not agreed upon. Eight cases of trigeminal neurinoma with extracranial extension are reviewed including the presented case. There were two males and six females, and the age varied from 16 to 65 years.(ABSTRACT TRUNCATED AT 250 WORDS)