Carriers for precipitating nucleic acids

One hundred and forty nine patients underwent thyroid and parathyroid surgery over a nine year period. The most common indications for surgery were the presence of a solitary thyroid nodule (56%) or the onset of pressure symptoms (30%). Carcinoma was found in 7.4% of cases. Wound complications occurred in 5%. The permanent nerve injury rate was 0.67%. The incidence of permanent hypothyroidism after surgery was 4%. No patients developed permanent hypoparathyroidism.     

分析仪器长期稳定性表征方法研究

仪器的长期稳定性影响测量准确性。仪器长时间测量产生漂移,将导致测量结果超出允许限度。通常采用长时间内测量结果的标准偏差或不同时段测量平均值的标准偏差来衡量仪器的长期稳定性。但如何准确判定仪器长期稳定性能否满足测量标准要求,未见报道。长期稳定性测量本质是监控分析结果的精密度和正确度。基于标准中重复性和时间变化的再现性数据,通过检验长期稳定性试验中每个时段测量结果的精密度和正确度,并检验时段内精密度、时段间总精密度、总平均值的正确度,给出了系统表征长期稳定性的方法,得到仪器不进行任何校正即可保证测量准确的时限TMAX。在TMAX时间内,实验室无需使用标样或控样,节约时间和成本。     

Comparison of plasmid- and chromosome-based polymerase chain reaction assays for detecting Chlamydia trachomatis nucleic acids

Several laboratories have demonstrated that the polymerase chain reaction (PCR) is more sensitive than culture or enzyme immunoassay (EIA) for detecting Chlamydia trachomatis in genitourinary tract specimens when various DNA targets are used for amplification, including the cryptic plasmid, major outer membrane protein (MOMP), or rRNA genes. We compared the performances of five different PCR assays, including assays with two plasmid, two MOMP, and one rRNA targets, by amplifying serial dilutions of C. trachomatis DNA and testing genitourinary tract specimens. By using published procedures, two different plasmid primers had sensitivities of 0.1 fg for C. trachomatis plasmid DNA and 10 fg for total cellular DNA. The sensitivities of the assays with the two MOMP primers were 0.1 and 10 pg, and the sensitivity for the assay with the rRNA primers was 1 pg for cellular DNA. Both plasmid-based assays detected 38 of 38 confirmed Chlamydiazyme-positive specimens, whereas the assays with the MOMP and rRNA primers detected 36 of 38 and 29 of 38 confirmed Chlamydiazyme-positive specimens, respectively. Six of 18 Chlamydiazyme-negative specimens collected from individuals whose specimens were positive by culture or immunofluorescence were positive by both plasmid-based PCRs; 4 of these were positive by PCR with the MOMP primers and 3 were positive by PCR with the rRNA primers. The results obtained with both purified DNA and genitourinary tract specimens indicated that the plasmid-based PCRs are more sensitive than bacterial chromosome-based PCRs for detecting C. trachomatis.     

A new heat shock protein that binds nucleic acids

Familial acromegaly/gigantism occurring in the absence of multiple endocrine neoplasia type I (MEN-1) or the Carney complex has been reported in 18 families since the biochemical diagnosis of GH excess became available, and the genetic defect is unknown. In the present study we examined 2 unrelated families with isolated acromegaly/gigantism. In family A, 3 of 4 siblings were affected, with ages at diagnosis of 19, 21, and 23 yr. In family B, 5 of 13 siblings exhibited the phenotype and were diagnosed at 13, 15, 17, 17, and 24 yr of age. All 8 affected patients had elevated basal GH levels associated with high insulin-like growth factor I levels and/or nonsuppressible serum GH levels during an oral glucose tolerance test. GHRH levels were normal in affected members of family A. An invasive macroadenoma was found in 6 subjects, and a microadenoma was found in 1 subject from family B. The sequence of the GHRH receptor complementary DNA in 1 tumor from family A was normal. There was no history of consanguinity in either family, and the past medical history and laboratory results excluded MEN-1 and the Carney complex in all affected and unaffected screened subjects. Five of 8 subjects have undergone pituitary surgery to date, and paraffin-embedded pituitary blocks were available for analysis. Loss of heterozygosity on chromosome 11q13 was studied by comparing microsatellite polymorphisms of leukocyte and tumor DNA using PYGM (centromeric) and D11S527 (telomeric), markers closely linked to the MEN-1 tumor suppressor gene. All tumors exhibited a loss of heterozygosity at both markers. Sequencing of the MEN-1 gene revealed no germline mutations in either family, nor was a somatic mutation found in tumor DNA from one subject in family A. The integrity of the MEN-1 gene in this subject was further supported by demonstration of the presence of MEN-1 messenger ribonucleic acid, as assessed by RT-PCR. These data indicate that loss of heterozygosity in these affected family members appears independent of MEN-1 gene changes and suggest that a novel (tissue-specific?) tumor suppressor gene(s) linked to the PYGM marker and expressed in the pituitary is essential for regulation of somatotrope proliferation.     

A simple procedure for solid-phase synthesis of peptide nucleic acids with N-terminal cysteine

Problems were encountered during attempts to prepare N-terminal cysteine-substituted peptide nucleic acids (PNAs) from commercially available, Fmoc-protected monomers. These problems have been surmounted by the use of an S-t-butylmercapto protecting group on the cysteine moiety. The solid-phase syntheses are carried out via a simplified procedure which should be generally useful for manual PNA synthesis.     

A general procedure for locating and analyzing protein-binding sequence motifs in nucleic acids

In the last decade, two tools, one drawn from information theory and the other from artificial neural networks, have proven particularly useful in many different areas of sequence analysis. The work presented herein indicates that these two approaches can be joined in a general fashion to produce a very powerful search engine that is capable of locating members of a given nucleic acid sequence family in either local or global sequence searches. This program can, in turn, be queried for its definition of the motif under investigation, ranking each base in context for its contribution to membership in the motif family. In principle, the method used can be applied to any binding motif, including both DNA and RNA sequence families, given sufficient family size.     

Resistance of materials based on silicon nitride to corrosion by solutions of some acids and alkalis

Conclusions Hot-pressed silicon nitride parts of 1.5–4% porosity containing a 10 wt. % activating addition of MgO are resistant to corrosion by nitric acid at room temperature and by 1% NaOH solution at 100°C under steady-state conditions. The presence of 1–20 wt. % CaF₂ added with the aim of improving antifriction properties results in corrosion in nitric acid, obeying the law m²=K, where K 5.5·10^–5· C³ %²/h). The corrosion is due to attack on specimens by hydrofluoric acid forming during the reaction between the CaF₂ and HNO₃.Translated from Poroshkovaya Metallurgiya, No. 1(205), pp. 70–72, January, 1980.     

A miniature mechanical ventilator for newborn mice

Transgenic/knockout mice with pre-defined mutations have become increasingly popular in biomedical research as models of human diseases. In some instances, the resulting mutation may cause cardiorespiratory distress in the neonatal or adult animals and may necessitate resuscitation. Here we describe the design and testing of a miniature and versatile ventilator that can deliver varying ventilatory support modes, including conventional mechanical ventilation and high-frequency ventilation, to animals as small as the newborn mouse. With a double-piston body chamber design, the device circumvents the problem of air leakage and obviates the need for invasive procedures such as endotracheal intubation, which are particularly important in ventilating small animals. Preliminary tests on newborn mice as early as postnatal day O demonstrated satisfactory restoration of pulmonary ventilation and the prevention of respiratory failure in mutant mice that are prone to respiratory depression. This device may prove useful in the postnatal management of transgenic/knockout mice with genetically inflicted respiratory disorders.     

Recent progress on analytical chemistry and biochemistry of D-amino acids

Recent findings that D-amino acids, especially D-aspartic acid and D-serine, exist in vivo in the mammalian tissues (brain and peripheries), prompted us now to investigate their biological and pathological roles in mammals. In this review, the overview of the progress of analytical chemistry and biochemistry of D-amino acids is described.     

Secretory immunoglobulins A from human milk possess affinity to oligonucleotides and nucleic acids

Dreams provide access to underlying personality structure, defensive and adaptive functions, and they elucidate the psychological forces that lead to overt symptomatic behavior. Two hundred three dreams of 39 personality disordered patients were factor analyzed and compared with Hall and Van de Castle's normative data (Hall C, Van de Castle RI [1966] The content analysis of dreams. New York: Appleton-Century-Crofts). Results included a five-factor solution that sheds light on some core issues of the dreamers. Comparisons between the groups resulted in the personality-disordered group demonstrating more estrangement in their dreams, fewer interactions, and more emotionality. In their interactions, they demonstrated a lower ratio of aggressive interactions yet a higher tendency to view themselves as the aggressor. Results are related to theoretical literature on personality and defensive styles, mostly from a psychodynamic perspective.     

Recommendations for the presentation of NMR structures of proteins and nucleic acids

The recommendations presented here are designed to support easier communication of NMR data and NMR structures of proteins and nucleic acids through unified nomenclature and reporting standards. Much of this document pertains to the reporting of data in journal articles; however, in the interest of the future development of structural biology, it is desirable that the bulk of the reported information be stored in computer-accessible form and be freely accessible to the scientific community in standardized formats for data exchange. These recommendations stem from an IUPAC-IUBMB-IUPAB inter-union venture with the direct involvement of ICSU and CODATA. The Task Group has reviewed previous formal recommendations and has extended them in the light of more recent developments in the field of biomolecular NMR spectroscopy. Drafts of the recommendations presented here have been examined critically by more than 50 specialists in the field and have gone through two rounds of extensive modification to incorporate suggestions and criticisms.     

A method for a selective local application of radioactive precursors of nucleic acids to the cow ovary

OBJECTIVE: To determine whether genetic polymorphism of cytochrome P450 (CYP) 2C9 affects the in vivo metabolism of warfarin enantiomers. METHODS: Eighty-six Japanese patients heart disease who were given warfarin participated in the study. Plasma unbound concentrations of warfarin enantiomers and urinary (S)-7-hydroxywarfarin concentrations were measured by means of a chiral HPLC and ultrafiltration technique to calculate the unbound oral clearance (CLpo,u) for the enantiomers and the formation clearance (CLm) for (S)-warfarin 7-hydroxylation. Genotyping for CYP2C9 (the wild type [wt], Arg144/Cys, and I1e359/Leu) and for CYP2C19 (wt, ml, and m2) was performed with a polymerase chain reaction method. RESULTS: Three patients were heterozygous for the CYP2C9 Leu359 mutation but none were homozygous for the mutation (the allele frequency of 0.017). None had a CYP2C9 Cys144 allele. The medians for (S)-warfarin CLpo,u and its 7-hydroxylation CLm obtained from heterozygotes of CYP2C9 Leu359 were significantly less than those obtained from homozygotes of the wt allele, as follows: 234 ml/min (range, 156 to 269 ml/min) versus 632 ml/min (range, 180 to 2070 ml/min) (p < 0.001) and 0.20 ml/min (range, 0.05 to 0.77 ml/min) versus 0.80 ml/min (range, 0.05 to 14.9 ml/min) (p < 0.05), respectively. In contrast, no difference was observed in (R)-warfarin CLpo,u between the groups. The allele frequencies for CYP2C19 m1 and CYP2C19 m2 were 0.26 and 0.14, respectively, indicating 15% of patients were genotypically poor metabolizers of CYP2C19. No difference in CLpo,u for warfarin enantiomers was observed between the assumed CYP2C19 phenotypes. CONCLUSION: Heterozygotes for CYP2C9 I1e359/Leu allele have reduced in vivo metabolism of (S)-warfarin but not (R)-warfarin. Because (S)-warfarin has a greater anticoagulant potency than its (R)-congener, the genetic polymorphism of CYP2C9 may partly account for the large interpatient variability in therapeutic dosages of warfarin.     

基于避险设施的火灾救援及避灾路线算法

以VC#.net、SQL Server 2008和地理信息系统为平台,对矿井地图进行了具有地理属性开发的研究,建立了图形库、数据库、方法库和知识库,并构建了基于避险设施的矿井火灾应急救援系统。对矿井火灾进行了实时在线模拟,分析和预测了火灾动态发展趋势,实现了矿井火灾烟流传播和最佳避灾路线的动态可视化显示功能。引入安全性、通行效率等因素对灾后巷道通行能力的变化进行修正,制定了基于避险设施的最优避灾路线选择原则和\     

A spectrofluorometric method for determining plasma allantoin based on the glyoxylate reductase reaction

Messenger RNA has been isolated from rat lens tissue. The mRNA species which codes for the A2 chain of alpha-crystallin, revealed the same extremely high sedimentation value (14S) as the corresponding messenger from calf lens. However, it has been shown that in rat lens the 14-S messenger preparation directs the synthesis of an additional alpha-crystallin chain, designated as alpha-X with an approximate molecular weight of 24000. For comparative purpose crystallin synthesis has also been studied as well in cultured rat lens cells as in the rat lens cell-free system.     

An abrasive material based on silicon nitride for grinding unhardened steels

Conclusions A study was made of the strength of abrasive grains of silicon nitride and of the wear resistance of silicon nitride material under conditions simulating the operation of abrasive grains in a grinding wheel. It is shown that in grain strength the new silicon nitride material is superior to diamond, Kubonit, and El'bor and inferior to Geksanit-A, while in wear resistance in the microcutting of unhardened steel it is comparable with Geksanit-A. On the basis of an electron microscopical examination of the surface structure of a worn microtool a mechanism is proposed for the wear of a material based on silicon nitride in the grinding of unhardened steel. A material based on silicon nitride could be successfully used in abrasive tools for the rough grinding of unhardened ferrous alloys.Translated from Poroshkovaya Metallurgiya, No. 5(173), pp. 34–37, May, 1977.