The active site of carboxypeptidase Taq possesses the active-site motif His-Glu-X-X-His of zinc-dependent endopeptidases and aminopeptidases

Carboxypeptidase (CPase) Taq possesses the His–Glu–X–X–Hissequence, which is the consensus sequence in the active siteof zinc-dependent endopeptidases and amino-peptidases, at positions276–280. Amino acid replacement of the conserved His andGlu drastically diminished the activity of CPase Taq, and thezinc content of the enzyme was also greatly reduced when eitherof the two His residues was replaced with Arg or Tyr. The resultsindicate that this sequence actually functions as the activesite in CPase Taq, showing that CPase Taq is a novel type ofzinc-dependent CPase that possesses the His–Glu–X–X–Hisactive-site motif.     

Participation of NK1.1+ T cells in the rejection of lpr alphabetaT cells when bone marrow cells of lpr mice are transplanted into B6 mice

BACKGROUND: Cause-of-death statistics are widely used for comparing health characteristics of European Community (EC) countries. Before attempting to interpret between-country differences, it is essential to assess the biases affecting the comparability of the data. EUROSTAT decided to address globally this problem with the objective to improve the quality and comparability of cause-of-death data within the EC. METHODS: The material is based on a review of results of international comparative cause-of-death studies and on specific inquiries among EC. Both cause-of-death certification and codification practices are analysed. Certification is studied comparing the models of death certificates, the type of information captured, certifiers training and querying practices. The different coding systems are analysed (International classification of diseases (ICD) in use, interpretation of the ICD rules, implementation of automated coding systems). RESULTS: International studies on comparability of certification and coding practices between countries are rare. These studies are based on certification of cases histories and recoding of samples of death certificates. Recent studies on respiratory diseases, cancers and diabetes outline differences that influenced on the reported level of mortality. The specific EUROSTAT investigation (1997) outline general discrepancies: models of death certificates, nature and amount of information entered, way to establish the diagnosis, degree of consistency of the certification process, autopsy practices, certifiers practices, implementation of ICD-10 and implementation of automated coding systems. CONCLUSION: EUROSTAT studies are now focused on causes of death requiring special attention for comparability (e.g. suicide, accidental deaths, drug and alcohol related deaths, unknown and ill-defined causes), on procedures to improve the homogeneity of certifiers training and querying practices, on the effect of the transition to ICD-10. The international model of death certificate recommended by the World Health Organization should be adopted as widely as possible. Uniform complementary information (e.g. surgery, pregnancy, autopsy, place of occurrence of accidental deaths, work accident) should also be adopted. The EUROSTAT investigations must result in definitions of common recommendations and guidelines to EC.     

Possibility of different cancer development between the proximal and distal colon: comparison of the distribution between adenomatous polyps and cancer

BACKGROUND/AIM: The aim of this study was to compare the distribution of adenomatous polyps with that of cancer in the colon by using adenomatous polyps removed by colonoscopy. METHODOLOGY: 1223 adenomatous polyps removed by an endoscopic polypectomy were compared with 226 colon cancers with regard to their distribution, size and age. RESULTS: With patients over 65 years of age, the incidence of adenomatous polyps was lower in the proximal colon than in the distal colon, however, the incidence of cancer was higher in the proximal colon than in the distal colon (p<0.05). The distribution of adenomatous polyps according to size was also significantly different between the proximal and distal colon (p<0.05). CONCLUSION: These results thus suggest that some difference may exist in cancer development between the proximal and distal colon.     

Spinal and femoral bone mass accumulation during normal adolescence: comparison with female patients with sexual precocity and with hypogonadism

Since the attainment of higher bone mineral density (BMD) is a crucial strategy in preventing age-related bone loss and consequent fracture, we determined when bone mass of the lumbar spine (L2-L4) (g/cm2) and femoral neck (g/cm2) reaches its peak in healthy Japanese subjects and examined the influence of early exposure to estrogen and estrogen deficiency on BMD. We also determined the volumetric BMD, termed bone mineral apparent density (BMAD), of the lumbar spine and femoral neck. Using dual-energy x-ray absorptiometry (DXA) (Hologic QDR-1000), we measured BMD of both the lumbar spine and the femoral neck in 31 healthy children aged 2-11 yr, 269 children (138 males and 131 females) aged 13-19 yr, 12 men and 12 women aged 20-34 yr as adult controls, 11 patients with female central sexual precocity, and 3 patients with female primary hypogonadism. Because the densitometric data obtained from DXA are strongly influenced by the size of the bone in growing subjects, the volumetric BMAD (g/cm3) of the vertebral cube (L2-L4) and femoral neck were determined: BMAD (g/cm3) = BMD (g/cm2)/square root of scanned area (cm2) for the lumbar spine and by BMAD = BMD/width for the femoral neck. The BMD, both lumbar spine and femoral neck, nearly reached its peak at age 14.5-15 yr in girls and 16.5-17 yr in boys when compared with adult normal values. The difference in this age between sexes is identical to the difference in age at sexual maturation. BMD in patients with sexual precocity was high compared to age-matched controls, whereas patients with primary hypogonadism showed lower lumbar apparent BMD, and the increase in lumbar BMAD (g/cm3) was noted after the progression of puberty in healthy children, probably suggesting the importance of sex steroids in the increase of BMD and lumbar BMAD in both sexes. The girls with earlier menarche showed higher lumbar BMD at age 18 and 19 yr. For the femoral BMAD, there was no significant relationship between this value and age in girls. We conclude that peak bone mass is mainly achieved by late adolescence in Japanese as in Caucasians and that pubertal progression and probably estrogen itself play a crucial role in accumulation of bone mass in females.     

Long-term forecast of Ca leaching from mortar and associated degeneration

The purpose of this study is the long-term forecast of Ca leaching from mortar and degeneration with Ca leaching. First, a technique for long-term forecasting of Ca leaching from mortar was constructed. Here, Ca is made to dissolve out by combining the electrochemical acceleration test with the diffusion test; it was converted on the basis of Ca leaching rate in real time and was carried out to a long-term forecast of Ca leaching. Next, the long-term forecast technique of mortar degeneration with Ca leaching was constructed. Here, Ca is made to dissolve out by the electrochemical acceleration test, and the mortar was evaluated experimentally. The result of the accelerated degeneration test was checked with the real time conversion result obtained by the long-term forecast of Ca leaching. Finally, predicted results of the degradation with Ca leaching were compared with the survey result of existing structures used for 30 years.     

Tensile behavior change depending on the microstructure of a Fe–Cu alloy produced from rapidly solidified powder

The relationship between consolidating temperature and the tensile behavior of iron alloy produced from Fe–Cu rapidly solidified powder is investigated. Fe–Cu powder fabricated by high-pressure water atomization was consolidated by heavy rolling at 873–1273 K. Microstructural changes were observed and tensile behavior was examined. Tensile behavior varies as the consolidating temperature changes, and these temperature-dependent differences depend on the morphology of the microstructure on the order of micrometers. The sample consolidated at 873 K shows a good strength/elongation balance because the powder microstructure and primary powder boundaries are maintained. The samples consolidated at the higher temperatures have a microstructure of recrystallized grains, and these recrystallized samples show the conventional relationship between tensile behavior and grain size in ordinal bulk materials.     

Serous cystadenoma of the pancreas with invasive growth: benign or malignant?

We describe a case of serous cystadenoma, that invaded a lymph node and adipose tissue. Preoperatively, the cystic lesion of the pancreas was diagnosed as a serous cystadenoma and subsequently the patient, a 71-yr-old woman, underwent distal pancreatectomy with splenectomy. Macroscopically, a greyish white, externally lobulated and partly ovoid tumor, measuring 12 x 8.5 x 5 cm, occupied the pancreatic body and tail extensively. In cross-section, multiple nodules were observed, which measured from 0.5 to 3 cm in diameter, were separated by hyalinized fibrous septa and were filled with numerous microcysts. Light microscopic findings were consistent with those for serous cystadenoma. At the splenic hilus, the tumor was found to have invaded the lymph node and adipose tissue. Based on the clinicopathological features of the six reported cases, including the present case (which behaved in a malignant fashion in terms of pathological findings of invasion or metastasis), serous cystadenoma should be regarded as having the potential for malignant growth.     

Glutathione concentration may be a useful predictor of response to second-line chemotherapy in patients with ovarian cancer

BACKGROUND: No useful predictor of resistance or sensitivity to second-line chemotherapy is known for ovarian cancer. The objective of this prospective study was to determine the utility of tumor glutathione S-transferase-pi (GST-pi) expression or glutathione (GSH) concentration in predicting ovarian cancer patients' responses to second-line chemotherapy. METHODS: Tumor samples were obtained from 26 patients with relapsed epithelial ovarian cancer 3-4 weeks before the initiation of second-line chemotherapy with etoposide (daily on Days 1-5) and cisplatin (on Day 5). The expression of GST-pi in tumor samples was determined by immunohistochemical staining and Western blot analysis. GSH concentration was measured by an enzymatic assay. RESULTS: The response rate was 38.4%. The estimated 3-year survival rate for the responders (66.7%) significantly exceeded that for the nonresponders (9.1%). Expression of GST-pi by immunohistochemical staining was more frequently observed in nonresponders (2 of 10 responders vs. 11 of 16 nonresponders). Western blot analysis detected GST-pi in all cases. There was no significant difference in the relative density values of the GST-pi Western blot analysis between the two groups. The mean value of GSH concentration in nonresponders was significantly higher than in responders (18.4 +/- 9.7 vs. 7.5 +/- 8.2 microg/mg protein). GSH concentration was below the cutoff point (10.3 microg/mg protein) in all responders except one. CONCLUSIONS: Second-line chemotherapy consisting of etoposide and cisplatin is effective in the treatment of relapsed epithelial ovarian cancer. In addition, tumor concentration of GSH may be a useful predictor of the response to this therapy.     

Preparation of magnetic fluid having active-gas resistance and ultra-low vapor pressure for magnetic fluid vacuum seals

The magnetic fluid, having an ultra-low vapor pressure property of 7·0×10⁻¹⁰ Pa at 293 K, was prepared. Hexafluoropropylene oxide polymer oil having high molecular weight was used as base oil. Magnetic particles were dispersed by using two types of new designed and synthesized hexafluoropropylene oxide acid derivative surfactants. The obtained magnetic fluid had a saturation magnetization of 35·0 mT, its magnetite particles were dispersed stably and showed a superior resistance to active gasses. It was ascertained that the magnetic fluid vacuum seal using the prepared fluid had the ultra high vacuum performance.