Asymptomatic adrenal tumor; 386 cases in Japan including our 7 cases

To clarify the indication of surgery in incidentally discovered asymptomatic adrenal masses, we analyzed 386 Japanese cases, 379 cases reported in Japan during the past 25 years (from 1964 to 1988) and 7 cases from our own experience. From a total of 460 patients, we carefully selected 379 patients satisfying our criterion of the absence of symptoms and signs suggestive of active hormone over-secretion as described in each case report. From the Japanese series, there was a high incidence of pheochromocytoma patients (20 of 37 patients) who had no symptoms and signs but had high plasma or urine catecholamines. Scintigraphy with 131I-meta-iodo-benzyl-guanidine was useful in the diagnosis of pheochromocytoma. For the other asymptomatic adrenal tumors, except for myelolipoma and adrenal cyst, differential diagnosis between malignant and benign adrenal lesions by imaging procedures such as whole body computed tomography (CT), ultrasonography (US), adrenocortical scintigraphy, and angiography was not always possible. In addition, among the 109 patients with cortical tumors whose hormonal data were reported, no clear-cut differentiation of malignant tumor from benign by means of these data could be obtained. Since 1980 whole body CT scanner and high resolution US scanner have become widely available, and there have been 283 cases of asymptomatic adrenal tumors who satisfied our criterion. Cortical carcinomas smaller than 3 cm and 6 cm in diameter account for 3.8% and 6.6%, respectively, of the total of 101 cases of cortical carcinoma, cortical adenoma, ganglioneuroma, and hemangioma during this period. The size of the smallest cortical carcinoma with metastasis was 2 cm in diameter in this series. Pre-operatively, an adrenocortical carcinoma 2.8 cm in diameter in our patient could not be diagnosed as such by imaging techniques and measurement of plasma hormones. These findings suggest that an adrenal mass larger than 3 cm should be removed and a patient with a smaller cortical tumor should be carefully followed up.     

提高免疫毒素DT386-GMCSF在E.coli中表达量的研究

以人粒细胞-巨噬细胞集落刺激因子（GM-CSF）受体（GM-CSFR）为靶向的白喉毒素（DT）与GM-CSF免疫毒素DT386-GMCSF为急性髓系白血病提供了一种新的替代治疗途径,但该蛋白在E.coli中的表达量很低,难以进行工业化生产。为探索造成其低表达的关键影响因素,对DT386-GMCSF中的GM-CSF进行了C端的截短表达,发现GM-CSF中L114编码序列可明显影响融合蛋白的表达量。在此基础上,构建了一系列突变体,发现保留1-123位氨基酸且将L114L115V116突变为G114V115T116的突变体DF123GVT的表达量高于DT386-GMCSF,且对来源于高表达GM-CSF受体的HL60细胞的肿瘤单细胞具有相似的细胞毒作用。DF123GVT突变体的获得为GM-CSFR靶向的免疫毒素的开发应用打下了基础。     

Activity and structure of the active-site mutants R386Y and R386F of Escherichia coli aspartate aminotransferase

Arginine-386, the active-site residue of Escherichia coli aspartate aminotransferase (EC 2.6.1.1) that binds the substrate alpha-carboxylate, was replaced with tyrosine and phenylalanine by site-directed mutagenesis. This experiment was undertaken to elucidate the roles of particular enzyme-substrate interactions in triggering the substrate-induced conformational change in the enzyme. The activity and crystal structure of the resulting mutants were examined. The apparent second-order rate constants of both of these mutants are reduced by more than 5 orders of magnitude as compared to that of wild-type enzyme, though R386Y is slightly more active than R386F. The 2.5-A resolution structure of R386F in its native state was determined by using difference Fourier methods. The overall structure is very similar to that of the wild-type enzyme in the open conformation. The position of the Phe-386 side chain, however, appears to shift with respect to that of Arg-386 in the wild-type enzyme and to form new contacts with neighboring residues.     

Genetic analysis of phenylacetic acid catabolism in <Emphasis Type="Italic">Arthrobacter oxydans</Emphasis> CECT386

Arthrobacter oxydans CECT386 is a Gram-positive bacterium able to use either phenylacetic acid or phenylacetaldehyde as the sole carbon and energy source for aerobic growth. Genes responsible for the catabolism of these compounds have been located at two chromosomal regions and were organized in one isolated paaN gene and two putative paa operons, one consisting of the paaD, paaF, tetR and prot genes, and one consisting of the paaG, paaH, paaI, paaJ, paaK and paaB genes. The identity of the paaF and paaN genes was supported by functional complementation experiments. A comparison with the paa catabolic genes and/or gene clusters of other bacteria that degrade these aromatic compounds is presented. The results of this study broaden the knowledge regarding the range of metabolic potential of this strain and eventually make it attractive for environmental applications.     

The role of anti‐PAc (361–386) peptide SIgA antibody in professional oral hygiene of the elderly

Objective: Measurement of salivary IgA antibody (PAc‐peptide antibody, PPA) to amino acid residues 361–386 of Streptococcus mutans PAc, which possess a multiple binding motif to various HLA‐DR molecules and a B‐cell epitope that recognises the inhibiting antibody to S. mutans, is an indicator for the population numbers of mutans streptococci (MS) in human saliva. The purpose of this study was to clarify the role of PPA in infection control of MS after professional oral hygiene care. Materials and methods: Thirty‐nine dependently living institutionalised elderly subjects (75.9 ± 7.5 years; 10 males, 29 females) participated in the study. The measurements of PPA, MS, total streptococci (TS) and lactobacilli (LB) were performed by ELISA and culture techniques from saliva, plaque and tongue samples from the elderly. Results: After treatment using professional oral care, the numbers of MS decreased significantly at 6 months in saliva and tongue samples from the group not having PPA in comparison with the primary data; whereas in the PPA‐detected group, a significant decrease in MS number was shown immediately following professional care at 1–12 months in all samples. There was little difference in the numbers of LB at any of the time points. The numbers of TS decreased rapidly in PPA‐not detected group in comparison with the PPA‐detected group. Conclusion: PPA may be more effective for controlling MS number in the oral cavity after professional treatment. The measurement of PPA may be used for preventive instruction to dental caries at the chair side in the clinical setting.     

白喉毒素DT386片段的表达纯化及细胞毒性研究

基于白喉毒素 (diphtheriatoxin ,DT)的免疫毒素在临床试验中普遍发现毒性反应 ,但机制尚不清楚。据推测 ,免疫毒素的细胞毒性源自DT的酶活性区和跨膜转运区 (N端 386～ 388个氨基酸 ,DT₃₈₆)。为考察DT₃₈₆毒素片段与毒性反应的关系 ,将DT₃₈₆在E .coli中进行了表达、纯化 ,并初步观察了其细胞毒性。经Q SepharoseFF离子交换层析 ,获得纯度达 95 %的DT₃₈₆蛋白。DT₃₈₆杀伤HL60细胞的IC50 为 2× 1 0 -6mol L ,比免疫毒素的特异杀伤毒性低 1 0 0倍以上 ;但在高浓度下 ,DT₃₈₆可非特异性杀伤多种细胞。小鼠体内实验初步结果表明 ,给药剂量高则体内毒性反应强烈。结果提示免疫毒素的剂量限制毒性与DT₃₈₆的非特异细胞毒性有一定相关性 ,为进一步开展免疫毒素毒性相关研究提供了有益线索。