胎儿长骨超声测量准确性的研究

目的探讨不同超声扫查切面及角度对胎儿长骨测值的影响。方法对30例各种原因引产的胎儿，引产前超声测量肱骨长度和股骨长度；把引产后的胎儿放在水盆中模拟宫内环境对每一根长骨进行不同方向、不同切面、不同角度测量；对引产后的胎儿标本经过处理获得裸骨，用游标卡尺对裸骨进行精确物理测量，测量肱骨骨干及股骨骨干长度；对上述测量结果进行统计学分析比较。结果30例胎儿引产前后长骨超声测值差异无统计学意义。对比研究显示：（1）超声声束与长骨骨干成90。检测长骨长度与长骨裸长符合率最高，为96．7％（29／30），其他方向和角度测量符合率均高于80％；（2）四种方向的三个角度对胎儿长骨测值差异无统计学意义；（3）左右侧肱骨及股骨测值差异无统计学意义。结论超声声束与长骨骨干成90。时对长骨长度的测量最为准确，四种方向的三个角度对胎儿长骨测值差异无统计学意义。     

ELISA for measuring porphobilinogen deaminase in human erythrocytes

An ELISA method has been developed to quantitate human porphobilinogen deaminase in erythrocyte lysate. The antiserum used in the assay was raised against the erythropoietic form of human porphobilinogen deaminase. The IgG fraction was characterized by use of immunoblotting technique, rocket immunoelectrophoresis and immunotitration and shown to be monospecific. The measuring range of the method was from 4 ng to 50 pg. Intra- and inter-assay coefficients of variation were 6% and 7%, respectively. Erythrocyte lysates from 97 apparently healthy individuals were assayed giving a mean erythrocyte porphobilinogen deaminase protein concentration of 150 +/- 28 SD (micrograms/g Hb) and a specific enzyme activity of 750 +/- 140 SD (nkat/g). Eight patients with acute intermittent porphyria were also investigated. A decreased concentration of enzyme protein, i.e. 84 +/- 13 SD (micrograms/g Hb) with a normal specific activity, was found.     

Methodology of cultivating human tissue in diffusion chambers

The proliferative activity of human pulmonary carcinoma cells has been examined by autoradiography in 48 cultures in diffuse chambers, incubated with 3H thymidine under various conditions. 3H thymidine has been injected intraperitoneally to one group of animals, in another group the diffuse chambers have been removed from the animals and incubated in culture medium with 3H thymidine in the same concentration. The proliferation intensity of the cell cultures from the same patients has been virtually the same in both modes of incubation. This permits simplifying the autoradiography technique for such experiments, thus helping to avoid the difficulties connected with radioactive waste utilization.     

Standardization of methods for measuring plasminogen activator inhibitor activity in human plasma

We have standardized the measurement of plasminogen activator inhibitor type 1 (PAI-1) activity in plasma. One-chain tissue-type plasminogen activator (t-PA; EC 3.4.21.31; final activity, 5 int. units/mL) was incubated with plasma (final dilutions 1:4 to 1:40) in phosphate buffer (pH 7.4, ionic strength = 0.15) for 15 min at 37 degrees C, followed by acidification and measurement of residual t-PA activity by an amidolytic method. The PAI-1 activity assay was 98% specific for PAI-1 activity in samples from both pregnancy and nonpregnancy, and varied linearly with added plasma volume when the percent inhibition of t-PA was between 8% and 50%. For the standardized method, analytical recovery was 93 +/- 5%, the detection limit was 1.6 arbitrary units per milliliter (1 arb. unit of PAI-1 activity = inhibition of 1 int. unit of t-PA activity), and total imprecision was 10.2 (SD 0.7) arb. units/mL (CV = 7%, n = 20). The average PAI-1 activity in 10 healthy individuals drawn between 0800 and 1000 hours was 23.9 +/- 15.4 arb. units/mL. Compared with the standardized assay, two of three previously described assays underestimated PAI-1 activity in plasma by 77% and 85%, respectively.     

Capillary agar diffusion assay for measuring metronidazole in human gingival crevice fluid.

An agar diffusion assay in capillaries, with Fusobacterium nucleatum M2 as the indicator strain, has been developed to measure metronidazole concentrations in gingival crevice fluid. The assay allows the measurement of 1.9 micrograms of metronidazole per ml in sample amounts of 0.6 microliters.     

Validity of liquid chromatography with electrochemical detection for measuring dopamine in human plasma

We tested the validity of liquid chromatography with electrochemical detection (LCEC) for measuring dopamine levels in human plasma, by adding known amounts of dopamine standard to human plasma, and by comparison with levels obtained using the catechol-O-methyltransferase radioenzymatic (COMT-RE) assay technique. The correlation between the obtained dopamine concentrations and picograms of added standard was 1.00, and the correlation between the two assay techniques across 32 plasma samples was 0.97. These results demonstrate that LCEC validly measures human plasma dopamine.     

Comparison of double- and single-isotope enzymatic derivative methods for measuring catecholamines in human plasma

We directly compared the reliability of a single-isotope enzymatic derivative technique for measurement of plasma catecholamines with that of the well-established double-isotope method. A significant (p less than 0.001) correlation was observed between measurements (n = 52) in the two assays, both for norepinephrine (r = 0.97) and epinephrine (r = 0.80). Means and coefficients of variation for the two analytes in a pooled specimen of plasma, measured repeatedly during six months, were virtually identical by each assay method. Basal plasma catecholamine concentrations in two different groups of apparently healthy subjects were also similar by each method. Dopamine concentrations in plasma were consistently below the limits measurable by either technique. The single-isotope assay requires half the assay time and 1/200th the sample as the double-isotope method. We conclude that this assay is just as reliable as the double-isotope technique and gives virtually identical values for norepinephrine and epinephrine concentrations in the physiological range.     

Nucleotide diversity in the Hsp90 gene in natural populations of Drosophila melanogaster from Australia

Hsp90 is regarded as one of the best candidates for an evolved mechanism that regulates the expression of genetic and phenotypic variability. We examined nucleotide diversity in both the promoter and coding regions of Hsp90, the gene which encodes Hsp90 in Drosophila, in natural populations of Drosophila melanogaster from eastern Australia. We found that Hsp90 is polymorphic for only two nonsynonymous changes in the coding region, both of which are deletions of a lysine residue. One of these lysine deletions was in complete linkage disequilibrium with the inversion In(3L)P, and showed a significant association with latitude. The other lysine deletion reported here for the first time varied from 0 to 15% in natural populations, but did not show a clinal pattern. The regulatory and coding regions of Hsp90 showed very low nucleotide diversity compared to other nuclear genes, and chromosomes containing In(3L)P had lower levels of nucleotide diversity than the standard arrangements. Non‐neutral evolution of Hsp90 was not supported by analyses of either the regulatory or coding regions of the gene. These results are discussed within the context of Hsp90 variation being involved in thermotolerance as well as the expression of genetic and phenotypic variability.     

The diversity of human factors: illustrating the relevance for nursing

This article looks at a selection of human factors tools and activities that may be used in nursing practice to improve the safety of patient care. The Human Factors Walk-Around tool and the Foresight training programme are highlighted as means to raise awareness of systems factors that may compromise safety. Ideas are given on how to improve team skills, to consider risk proactively, and to influence the design of the healthcare system in which care is delivered.