Induction of mutations in mouse FM3A cells by treatment with riboflavin plus visible light and its possible relation with formation of 8-hydroxyguanine (7,8-dihydro-8-oxoguanine) in DNA

Photosensitized formation of 8-hydroxyguanine (oh⁸Gua; 7,8-dihydro-8-oxoguanine,oxo⁸Gua) in cellular DNA and its repair was examined in mouseFM3A cells. oh⁸Gua was generated 7-fold above the backgroundlevel by 10 min irradiation with visible light in the presenceof riboflavin (160 µM) and repaired to 60–70% ofinitial level after 2 h post-incubation. By this treatment,mutation frequency that was measured by counting ouabain-resistantcolonies, was increased 7-fold above the background frequency.The accumulation of unrepaired oh⁸Gua in DNA generated by treatmentwith riboflavin plus visible light correlates to induction ofmutations. Thus, oh⁸Gua will contribute to the mutation inducedby visible light as well as spontaneous mutations.     

Advanced primary non-Hodgkin's lymphoma of the small intestine in childhood: Report of four cases

Primary non-Hodgkin's lymphoma of the small intestine (PLI) is an uncommon malignancy in childhood which carries a poor prognosis. Consideration of the possible diagnosis of PLI is important when children have vague abdominal symptoms, since thoughtful multidisciplinary treatment can result in a better prognosis. This paper reports the cases of four children who have presented to our hospital since 1985 with advanced stage III or IV PLI. All the children had a huge abdominal mass but none of them had complete intestinal obstruction. Regarding the diagnosis, ultrasonography frequently reveals a hypoechoic thickening of the intestinal wall with dilated intestinal loops. A delayed primary or second-look operation may be the treatment of choice following adequate chemotherapy, while total parenteral nutritional support may prevent gastrointestinal complications. Three of the four patients have been in complete remission for 2 to 4 1/2 years since their initial treatment.     

Serum CEA levels facilitate detection of recurrences of cancer in patients after gastrectomy

In an attempt to assess the usefulness of carcinoembryonic antigen (CEA) for predicting the progression of gastric cancer, CEA productivity was evaluated according to serum CEA levels, at the time of recurrence or relapse. In cases of a recurrence, abnormal CEA levels were observed in 14 of 17 (82.4 per cent) with differentiated carcinoma and in 9 of 21 (42.9 per cent) with undifferentiated carcinoma. Preoperative abnormal CEA levels were observed in only 6 of 41 patients (14.6 per cent). A median lead time of manifestation of recurrence was 5 months. In those with relapse, 9 of 11 (81.8 per cent) patients with differentiated carcinoma and 13 of 18 (72.2 per cent) with an undifferentiated carcinoma had abnormal CEA levels. Preoperative abnormal CEA levels were observed in 24 of these 89 patients (27.0 per cent). Postoperative monitoring of CEA seems to be useful for early recognition of gastric cancer progression, irrespective of the preoperative CEA levels.     

Laser thermal angioplasty for early repair of anastomotic stenosis after lower extremity arterial reconstruction: initial experience

Laser thermal angioplasty with a sapphire hot-tip Nd-YAG laser system was effectively used for five grafts with anastomotic stenotic lesions which occurred after femoro-popliteal arterial reconstructions. Stenotic lesions were detected by a combination of Doppler flow waveform analysis and ankle/brachial index measurement in 32 femoro-popliteal and five femoro-tibial arterial bypass grafts in the postoperative period. The laser probe used was 3 to 4 mm in diameter. There were no perforations of the arterial wall caused by thermal ablation, even with repeated pulses of 40 watts of laser energy for 3 s. Contact Nd-YAG laser thermal angioplasty using this rounded, 3-4 mm hot-tip facilitated effective widening of the lumen of the anastomotic stenotic lesion. All patients remain well at follow-up from 9 to 20 months after laser thermal angioplasty.     

Clinicopathological features of elevated lesions of the duodenal bulb

We present here our findings on patients with an elevated lesion of the duodenal bulb. All these patients were treated in our clinics between the years 1984 and 1988. These lesions were present in 36 of 8,802 patients who underwent upper gastrointestinal pan-endoscopy. Two patients had a duodenal carcinoma, 2 an adenoma, and 1 a Brunner's gland adenoma. There were 15 with a hyperplastic polyp, 3 with a heterogenic gastric mucosa, 3 with Brunner's gland hyperplasia, 6 with duodenitis, and 4 with regenerative mucosa. Among these 36 lesions, only 69% (25 lesions) were evident on the upper gastrointestinal X-ray series. Adenoma and Brunner's gland adenoma were of a pedunculated form of the gross type and had an irregular surface mucosa. Both duodenal carcinomas were detected by endoscopic biopsy and were resected. Histologically, these lesions were limited to the submucosal layer and were of the non-pedunculated polypoid form, but there were no other characteristic endoscopic features, in comparison with other elevated lesions. Thus, upper gastrointestinal endoscopy with routine observations of the duodenal bulb plus endoscopic biopsy will lead to a definite diagnosis of these elevated lesions and to the early detection and treatment of this rare malignant lesion.     

Comparison of DNA content in gastric cancer cells between primary lesions and lymph node metastases

Cytophotomtric DNA contents of tumor cells in primary lesions and the corresponding metastatic lymph nodes were compared in 61 cases of gastric cancer to determine whether the DNA content remains stable during lymph node metastasis. The DNA distribution patterns were grouped into three types, according to the proportion of aneuploid cell population. Changes in DNA patterns between primary and metastatic lesions were evident in 36 of 61 patients (59.0%); in the remaining 25 (41.0%), the same DNA distribution patterns were noted for both lesions. In 33 of these 36, DNA pattern in the primary carcinoma was transformed into a more narrowly scattered one in the metastatic lesion of the lymph node. Mean and modal values and the frequency of cells over tetraploid (4c) or hexaploid (6c) were significantly higher in the primary lesion compared with findings in the metastatic lesions. This reduction in DNA content in the metastatic lesions was a more frequent occurrence in differentiated (18 of 23) than in undifferentiated adenocarcinoma (15 of 35) (P less than 0.01). Therefore, in primary lesions with a widely scattered DNA ploidy, the tumor cells with a smaller DNA ploidy frequently metastasized to lymph nodes, particularly in cases of a differentiated carcinoma. Such observations may be pertinent in future designing of treatment protocols.     

Synergistic effect of K-18 and concomitant hyperthermia for treatment of lewis lung carcinoma in mice

We investigated the synergistic anti-tumor effects of K-18 (conjugate of human γ-globulin and melphalan) and concomitantly administered hyperthermia on Lewis lung carcinoma in mice. The antitumor effect of a subeffective dose of K-18 or an equivalent dose of melphalan alone was enhanced by local hyperthermia. K-18 administration demonstrated a greater potentiation for inhibition of tumor growth than that of melphalan alone. Local hyperthermia plus K-18 reduced the dose of melphalan required for tumor growth inhibition by melphalan alone. The combined application of K-18 and hyperthermia for treating cancer warrants further study.     

Mercuric chloride induces the production of leukotriene B4 by rabbit alveolar macrophages

The effects of HgCl₂ on the production of leukotriene B₄ (LTB₄) by rabbit alveolar macrophages were investigated. Alveolar macrophages synthesized only a small amount of LTB₄ when incubated in Hanks’ balanced salt solution (HBSS) in the absence of stimuli or chemical reagents (0.2±0.1 ng/10⁶ cells). The amount of LTB₄ synthesized was greatly enhanced when macrophages were incubated with 5×10^?6 M HgCl₂ (5.3±0.2 ng/10⁶ cells). Increases in levels of free arachidonic acid (20∶4), a precursor of eicosanoids, were also observed on treatment of [³H]20∶4-labeled cells with HgCl₂ in a concentration-dependent manner. We confirmed that [³H]20∶4 was mainly liberated from the alkenyl subclass of ethanolamine glycerophospholipids (EGP). Degradation of alkenyl-EGP was also observed when HgCl₂ and [³H]20∶4-labeled lipids were incubated in HBSS, resulting in an increase in the level of [³H]20∶4-labeled lysoEGP. When a microsomal fraction prepared from macrophages was added to the same mixture, [³H]20∶4 was liberated from [³H]20∶4-containing lysoEGP. These results suggest that the alkenyl linkage of EGP was degraded in the presence of HgCl₂ with resultant formation of lysoEGP which was subsequently hydrolyzed by lysophospholipase. As a consequence, the level of free 20∶4 in and the rate of production of LTB₄ by alveolar macrophages were elevated.