DISCRIMINATION METHOD FOR GAMMA RAY DOSES IN NEUTRON FIELDS USING AN IONIZATION CHAMBER WITH ATTENUATION FILTERS.

Neutron fields produced by an accelerator-driven neutron source are generally mixed radiation fields that consist of fast neutrons and gamma rays. To estimate the biological effects of fast neutrons precisely, the gamma ray dose contamination must be evaluated in neutron fields. In this work, we developed a discrimination technique for absorbed doses (60Co gamma-ray equivalent) of fast neutrons and gamma rays using an ionization chamber. The filter thickness dependences of the absorbed doses of fast neutrons and gamma rays are different for a given filter material. Thus, the absorbed doses of each type of radiation were distinguished by fitting the dose attenuation curve, which was measured with an ionization chamber and attenuation filters, with a two-component exponential function. The absorbed dose of fast neutrons and gamma rays with no attenuation filter was evaluated from the y-intercept of the fitting function. This technique was demonstrated in two neutron fields produced by 4 MeV proton and deuteron bombardment of a 9Be target. The thicknesses of the polyethylene attenuation filters were 0-350 mm. The dose attenuation coefficients of fast neutrons obtained by the two-component exponential fitting function for the 9Be(p,n)9 and 9Be(d,n) reactions showed differences of 1.5 and 1.7%, respectively, from the reference measurements using a CR-39 plastic nuclear track detector. The absorbed dose contributions of gamma rays in neutrons fields of the 9Be(p,n)9B and 9Be(d,n) reactions were evaluated as 30.2 ± 3.24% and 20.4 ± 5.16%, respectively, without polyethylene filters.

Nucleotide sequence of the FAD synthetase gene from Corynebacterium ammoniagenes and its expression in Escherichia coli.

The nucleotides of a bifunctional enzyme FAD synthetase gene, which showed both flavokinase and ATP:FMN adenylyltransferase activities, from Corynebacterium ammoniagenes were sequenced. The FAD synthetase gene product consisted of 338 amino acids and had a calculated molecular weight of 37,712. The deduced protein sequence of the FAD synthetase shared a homology with those of the protein X of Escherichia coli, which has been reported to have both flavokinase and ATP:FMN adenylyltransferase activities like the FAD synthetase of C. ammoniagenes, and the protein X of Pseudomonas fluorescens. From the analysis of the flanking sequences of the FAD synthetase gene, the gene organization and the operon structure around the FAD synthetase gene of C. ammoniagenes were thought to be different from those of Gram-negative bacteria. An over-expression system of the FAD synthetase of C. ammoniagenes was constructed in E. coli to study the structure and function of the protein. Under the tandem tryptophan promoter, the FAD synthetase activity increased 2231 times compared to that of non-transformed C. ammoniagenes.

Cloning of FAD synthetase gene from Corynebacterium ammoniagenes and its application to FAD and FMN production.

The cloning of a bifunctional FAD synthetase gene, which shows flavokinase and FMN adenylyltransferase activities, from Corynebacterium ammoniagenes was tried by hybridization with synthetic DNAs corresponding to the N-terminal amino acid sequence. The cloned PstI-digested 4.4 x 10(3)-base (4.4-kb) fragment could not express the FAD synthetase activity in E. coli, but could increase the two activities by the same factor of about 20 in C. ammoniagenes. The FAD-synthetase-gene-amplified C. ammoniagenes cells were applied to the production of FAD from FMN or riboflavin. The productivity of FAD from FMN was increased four to five times compared with the parent strain, and reached a 90% molar yield. The productivity of FAD from riboflavin was increased about eight times, with a 50% molar yield. The addition of Zn2+ to the reaction mixtures for the conversion from riboflavin to FAD brought about the specific inhibition of adenylyl-transferase activity and resulted in the accumulation of FMN.

Nicardipine may impair glucose metabolism in hypertensive diabetic patients.

The respective effects of 6 month's administration of beta-blockers (atenolol, metoprolol, carteolol and arotinolol), calcium-channel blockers (nicardipine, diltiazem) and angiotensin converting enzyme inhibitor (enalapril) on hemoglobin A1c (HbA1c) levels were evaluated in hypertensive patients with non-insulin-dependent diabetes mellitus (NIDDM), using a retrospective method. NIDDM patients with stable HbA1c and body weight were selected for this study. The following results were obtained. (1) The administration of nicardipine or beta-blockers significantly elevated HbA1c levels. (2) The administration of diltiazem or enalapril did not have any influence on HbA1c levels. These findings suggest that not only beta-blocker but nicardipine (dihydropyridine type calcium-channel blocker) may cause deterioration in glucose metabolism in NIDDM patients.

Regional lymph node metastasis of early gastric cancer.

Of 122 patients hospitalized for early gastric cancer in 1974-1989, 15 were histologically found to have regional lymph node metastases. Tumor invasion was limited to the mucosa in 3 cases and to the submucosa in 12. An ulcer or ulcer scar was found in the tumor in 12 cases. Metastasis had occurred only to the perigastric nodes in 13 cases and also along the left gastric and/or common hepatic arteries in two. Preoperative endoscopic injection of Chinese ink into the submucosa revealed a high rate of uptake in regional lymph nodes along the left gastric, splenic and common hepatic arteries. Patients with early cancer should undergo gastrectomy with lymphadenectomy, particularly if the cancer contains an ulcer or has invaded the submucosa. If the patient's general health and life expectancy are poor, restricted surgery or endoscopic treatment should be considered.

[The relation of the DNA ploidy pattern to lymphatic permeation in pure-type diffuse infiltrative carcinomas of the stomach].

Lymphatic permeation (ly) is considered an important prognostic factor, even in the case of a diffuse infiltrative carcinoma (DICA) of the stomach, which generally has the poorest prognosis among the various types of gastric carcinomas. Our previous study has revealed that the ly in DICA is strongly related to the histological type of carcinoma that infiltrates the tumor tissue: the "mixed type", i.e., a type that includes tubular/trabeculoacinar element in 10% or more of the tumor tissue presents a significantly higher incidence of ly than the "pure type", i.e., a type that consists almost exclusively of anaplastic/mucocellular carcinoma. However, even in the "pure type" cases, some show a high ly incidence. To clarify this discrepancy, the DNA ploidy pattern in the "pure type" DICA was investigated, since the DNA ploidy has been reported to correlate well with the invasiveness or the metastatic tendency of the tumor. Although most of the cases (70%) showed a heteroploidy, such an incidence was significantly higher in the cases with a marked ly (86%) than in the cases without ly. (60%). As a result, we have concluded that in cases of a DICA, the lymphatic permeation (ly) is remarkably influenced not only by the histological type seen but also by the DNA ploidy pattern of the carcinoma.

[The histological type and lymphatic permeation of diffuse infiltrative carcinoma of the stomach].

Although diffuse infiltrative carcinomas of the stomach are mostly composed of anaplastic/mucocellular type, some cases show tubular/trabeculoacinar carcinoma in a large or small part of the tumor. We have subdivided diffuse infiltrative carcinoma into two subtypes, mixed type and pure type, from the viewpoint of the carcinoma's histological structure and lymphatic permeation (LP). The former, or mixed type, includes a tubular/trabeculoacinar element in at least 10% of the tumor tissue, and shows a high tendency for LP. On the other hand, the latter, or pure type, consists almost exclusively of anaplastic/mucocellular carcinoma with a low tendency for LP. No difference in the frequency of LP between males and females was found in the pure type carcinomas, but a significantly higher frequency and grade of LP was observed in males in the mixed type carcinomas. Further, even in the pure type, the LP was rather frequent in people 60 or more years old. Thus, lymphatic permeation seems to be influenced not only by the histological type of the carcinoma but also by sex and age.

Subcellular localization of two long-chain acyl-coenzyme-A synthetases in Candida lipolytica.

Studies have been made on the subcellular localization of two long-chain acyl-coenzyme-A synthetases as well as glycerolphosphate acyltransferase and the acyl-CoA-oxidizing system in Candida lipolytica grown on oleic acid. Acyl-CoA synthetase I is distributed among different subcellular fractions, including microsomes and mitochondria where glycerolphosphate acyltransferase is located. On the other hand, acyl-CoA synthetase II is localized in microbodies where the acyl-CoA-oxidizing system is located. These results support our previous conclusion that acyl-CoA synthetase I is responsible for the production of acyl-CoA to be utilized for the synthesis of cellular lipids, while acyl-CoA synthetase II provides acyl-CoA that is exclusively degraded via beta-oxidation.

Analysis of serum immunoglobulins in hereditary sensory radicular neuropathy.

Serum and salivary immunoglobulins were studied in 11 members of a family including 3 patients with hereditary sensory radicular neuropathy (HSRN) in 1 of whom serum immunoglobulins were measured over a period of about 6 years. It was confirmed that serum IgA and IgG levels rose as the disease progressed. Although our results do not agree, in part, with the findings of Whitaker et al. (1974) who reported an increase in IgA alone, the present study suggested that such dysimmunoglobulinaemia deserves further study. Whether dysimmunoglobulinaemia is a primary phenomenon related to the development of HSRN or simply a secondary change remains to be further explored.