Mutational effects of γ-rays and carbon ion beams on Arabidopsis seedlings

To assess the mutational effects of radiation on vigorously proliferating plant tissue, the mutation spectrum was analyzed with Arabidopsis seedlings using the plasmid-rescue method. Transgenic plants containing the Escherichia coli rpsL gene were irradiated with γ-rays and carbon ion beams (320-MeV ¹²C⁶⁺), and mutations in the rpsL gene were analyzed. Mutant frequency increased significantly following irradiation by γ-rays, but not by 320-MeV ¹²C⁶⁺. Mutation spectra showed that both radiations increased the frequency of frameshifts and other mutations, including deletions and insertions, but only γ-rays increased the frequency of total base substitutions. These results suggest that the type of DNA lesions which cause base substitutions were less often induced by 320-MeV ¹²C⁶⁺ than by γ-rays in Arabidopsis seedlings. Furthermore, γ-rays never increased the frequencies of G:C to T:A or A:T to C:G transversions, which are caused by oxidized guanine; 320-MeV ¹²C⁶⁺, however, produced a slight increase in both transversions. Instead, γ-rays produced a significant increase in the frequency of G:C to A:T transitions. These results suggest that 8-oxoguanine has little effect on mutagenesis in Arabidopsis cells.     

SLOW GROWING FLAT‐TYPE PRIMARY MALIGNANT MELANOMA OF THE ESOPHAGUS TREATED WITH CAP‐ASSISTED EMR

We report a rare case of flat‐type primary malignant melanoma of the esophagus treated with endoscopic mucosal resection (EMR). A 64‐year‐old woman was referred for examination of a small pigmented lesion located in the mid esophagus. On endoscopy, the lesion exhibited almost no change in size over the year. Cap‐assisted EMR was performed en bloc. The histopathological findings showed atypical melanocyte proliferation in the basal layer, spindle cells, and epithelioid cell proliferation with nuclear enlargement and a few mitotic figures. Histopathological examination confirmed the diagnosis of primary malignant melanoma. Immunostaining for S‐100 protein and HMB‐45 antibody were positive, and the Ki‐67 index was low. The patient was discharged without additional surgical resection and/or chemotherapy. The patient had no symptoms and no signs of recurrence 20 months after EMR. There has been no report on a slow growing esophageal melanoma. It is difficult to estimate the malignant behavior of this case.     

Comparison of endoscopic findings with symptom assessment systems (FSSG and QUEST) for gastroesophageal reflux disease in Japanese centres

Background and Aim: We compared endoscopic findings of the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG), a written questionnaire developed in Japan, to that for the questionnaire for the diagnosis of reflux esophagitis (QUEST) for the diagnosis of reflux esophagitis. Methods: We registered 475 patients with untreated symptoms of upper abdominal pain (male/female: 252/223, average age 52.4 ± 17.8 years). Subjects were assessed first with the FSSG and QUEST questionnaires, then by endoscopy, before allocation to a gastric ulcer (GU), duodenal ulcer (DU), gastroesophageal reflux disease (GERD) or functional dyspepsia (FD) group. Results: On the basis of the endoscopic findings the diagnoses for the 475 subjects were as follows: FD 52.2%, DU 7.6%, GU 7.8%, and GERD 32.4% (Grade M 10.1%, Grade A + B 20.2%, Grade C + D 2.3%). There was no difference between the FSSG and QUEST in sensitivity, specificity or accuracy for any condition. The FSSG score rose with increasing endoscopic severity of GERD, but there was no correlation between the QUEST score and endoscopic severity. The FSSG total score was inferior to QUEST in terms of distinguishing GERD from other conditions, but when only the questions relating to reflux symptoms were used, the FSSG was able to distinguish GERD from other conditions as well as QUEST. Conclusions: The FSSG score reflects the severity of the endoscopic findings of GERD.     

Captopril improves impaired endothelium-dependent vasodilation in hypertensive patients.

Animal studies suggest that some angiotensin converting enzyme inhibitors augment endothelium-dependent vasorelaxation. We aimed to determine if captopril augments endothelium-dependent vasodilation in middle-aged hypertensive patients. By using strain-gauge plethysmography, forearm vasodilation evoked with intra-arterial acetylcholine (4, 8, 16, and 24 micrograms/min) or nitroprusside (0.2, 0.4, 0.8, and 1.2 micrograms/min) was examined before and after captopril administration (25 mg per os). Before captopril, forearm vasodilation with acetylcholine was less in hypertensive patients (n = 12) than in age-matched (n = 7) or young (n = 7) normotensive subjects, but forearm vasodilation with nitroprusside did not differ among the three groups. Captopril improved forearm vasodilation in hypertensive patients (n = 7) with acetylcholine but nitroprusside did not. In contrast, nifedipine (10 mg per os) did not alter forearm vasodilation with acetylcholine or nitroprusside in hypertensive patients (n = 5). The decreases in mean blood pressure caused by captopril and nifedipine in hypertensive subjects were comparable. Captopril did not alter forearm vasodilation with acetylcholine or nitroprusside in young normotensive subjects (n = 7). These results suggest that captopril in hypertensive patients may acutely improve impaired endothelium-dependent forearm vasodilation that does not result from reduction in blood pressure per se.     

Attenuated forearm vasodilative response to intra-arterial atrial natriuretic peptide in patients with heart failure

It has been shown that renal responses to atrial natriuretic peptide (ANP) are markedly attenuated in patients with heart failure. This study aimed to determine if vasodilative response to ANP is altered in patients with heart failure. In patients with heart failure (n = 7) and age-matched normal subjects (n = 7), forearm blood flow was measured using a strain-gauge plethysmograph during intra-arterial infusion of alpha-human ANP (50, 100, 200, and 400 ng/min) or nitroglycerin (100, 200, 400, and 600 ng/min). Forearm vasodilatation evoked with intra-arterial alpha-human ANP in patients with heart failure was considerably less (p less than 0.01) than that in normal subjects. In contrast, nitroglycerin produced comparable forearm vasodilatation in the two groups. Plasma ANP and cyclic guanosine monophosphate (GMP) levels at rest were higher in patients with heart failure than in normal subjects (p less than 0.05 for both), but the increases in plasma ANP and cyclic GMP in the venous effluents during intra-arterial ANP infusion did not differ between the two groups. These results indicate that the direct vasodilative effect of ANP on forearm vessels was attenuated in patients with heart failure as compared with that in normal subjects. The mechanisms responsible for this alteration are not clear but might involve mechanisms other than down-regulation of the ANP receptors because the increases in venous plasma cyclic GMP caused by intra-arterial ANP were comparable between patients with heart failure and normal subjects.     

Mycoplasma pneumoniae isolation and IHA antibody detection in patients with M. pneumoniae infection

Throat swab culture was compared with indirect hemagglutination (IHA) antibody detection for diagnosis of Mycoplasma pneumoniae infection. These two methods were tried on the patients several times for a long term after onset of the disease. For five years from 1982 to 1986 in Kanagawa prefecture, a total of 566 patients were tested and 141 (25%) were diagnosed as M. pneumoniae infection by either of the two test methods. Both culture and antibody detection were performed on 110 patients out of 141, revealing that 96 patients (87%) were positive by culture and 89 (81%) were positive by antibody detection. Most of the patients with M. pneumoniae infection showed positive culture within a week after onset of the disease, and half of the patients treated with antibiotics such as macrolides or tetracyclines showed positive for two or three months after the onset. Positive rate of IHA antibody detection in the patients with M. pneumoniae infection was 43% within a week after onset of the disease and reached the maximum (92%) in 15 to 21 days after the onset. The rate did not decrease to less than 70% three months after the onset. Geometric mean titer of the antibody reached the maximum at the same time as the antibody positive rate. Both antibody positive rate and geometric mean titer declined significantly four months after the onset. In general, IHA antibody of infants with M. pneumoniae infection increased satisfactorily day by day after onset of the disease. Nine percent of the patient with M. pneumoniae infection developed otitis media with effusion, and M. pneumoniae was isolated from two of six patient effusions.