Analysis of three restriction fragment length polymorphisms in the human type II procollagen gene

Cloned genomic DNA sequences corresponding to various regions of the human type II procollagen gene were used to analyze the DNA from 78 normal volunteers. Southern hybridization experiments detected polymorphic HindIII, BamHI, and EcoRI sites. The presence of the polymorphic HindIII site results in a 7.0-kilobase (kb) band, and the absence of this site results in a 14.0-kb band. When present, the BamH1 polymorphic site yields a 4.8-kb band, and when absent, yields a 7.2-kb band. The presence of the EcoRI polymorphic site results in a 3.7-kb band, and its absence results in a 7.0-kb band. Each polymorphic site was mapped. Analyses of the data demonstrated that the sites are present in overall gene frequencies of .39 for HindIII, .04 for BamHI, and .02 for EcoRI. Gene frequencies of the polymorphic sites were also studied with respect to race. The polymorphic sites are present in a Hardy-Weinberg distribution in the study population. Study of an extended family demonstrated that the segregation of the HindIII polymorphic site is consistent with Mendelian inheritance.     

Accurate wavelength measurements of a putative standard for near-infrared diffuse reflection spectrometry

The diffuse reflection (DR) spectrum of a sample consisting of a mixture of rare earth oxides and talc was measured at 2 cm-1 resolution, using five different accessories installed on five different Fourier transform near-infrared (FT-NIR) spectrometers from four manufacturers. Peak positions for 37 peaks were determined using two peak-picking algorithms: center-of-mass and polynomial fitting. The wavenumber of the band center reported by either of these techniques was sensitive to the slope of the baseline, and so the baseline of the spectra was corrected using either a polynomial fit or conversion to the second derivative. Significantly different results were obtained with one combination of spectrometer and accessory than the others. Apparently, the beam path through the interferometer and DR accessory was different for this accessory than for any of the other measurements, causing a severe degradation of the resolution. Spectra measured on this instrument were removed as outliers. For measurements made on FT-NIR spectrometers, it is shown that it is important to check the resolution at which the spectrum has been measured using lines in the vibration-rotation spectrum of atmospheric water vapor and to specify the peak-picking and baseline-correction algorithms that are used to process the measured spectra. The variance between the results given by the four different methods of peak-picking and baseline correction was substantially larger than the variance between the remaining five measurements. Certain bands were found to be more suitable than others for use as wavelength standards. A band at 5943.13 cm-1 (1682.62 nm) was found to be the most stable band between the four methods and the six measurements. A band at 5177.04 cm-1 (1931.61 nm) has the highest precision between different measurements when polynomial baseline correction and polynomial peak-picking algorithms are used.     

Spill behaviour using REACTPOOL. Part II. Results for accidental releases of silicon tetrachloride (SiCl(4))

Silicon tetrachloride is a toxic, corrosive water reactive substance that is used widely in the process industries. On spillage from containment it creates liquid pools that can either boil or evaporate. The main feature of the pool behaviour is the exothermic reaction with water. There are three sources of water available for reaction: free ground water, substrate water and atmospheric moisture. Hydrogen chloride gas and ortho-silicic acid solid (or silica gel) are produced by the hydrolysis reaction. The purpose of this paper is to describe the dangers involved in cases of accidental releases of silicon tetrachloride, to report its properties, referring to toxicity data, major accidents and mitigation tests. It also describes pool behaviour using REACTPOOL [1]. Model results indicate that the pool behaviour is governed mainly by the amount of water available for reaction. Surface roughness and wind speed also have a significant effect on the results. Results are compared with those for other water reactive chemicals in Part III of this series of papers [3]. The generated cloud will initially contain silicon tetrachloride and hydrogen chloride with numerous processes taking place.Although silicon tetrachloride has been involved in many major hazard incidents, there are no experimental data relevant to the modelling requirements.     

Low-dispersion turns and junctions for microchannel systems

Numerical methods are employed to optimize the geometry of two-dimensional microchannel turns such that the turn-induced spreading of a solute band is minimized. An inverted numerical method is first developed to compute the electric potential and local species motion in turns of arbitrary geometry. The turn geometry is then optimized by means of a nonlinear least-squares minimization algorithm using the spatial variance of the species distribution leaving the turn as the object function. This approach yields the turn geometry producing the minimum possible dispersion, subject only to prescribed constraints. The resulting low-dispersion turns provide an induced variance 2-3 orders of magnitude below that of a comparable conventional turns. Sample results are presented for 180 and 90 degrees turns, and the use of these turns to form wyes and tees is discussed. A sample 45 degrees wye is presented. The use of low-dispersion turns in folding separation columns is also discussed, and sample calculations are presented for folding a column 100 microm in width and up to 900 mm in length onto a region of only 10 by 10 mm. These low-dispersion geometries are applicable to electroosmosis, electrophoresis, and some pressure-driven flows.     

The activation of mechanisms linking judgements of work design and management with musculoskeletal pain

The report of work-related musculoskeletal pain may be related to worker evaluations of the design and management of work through two mechanisms: one biomechanical and the other stress-related. This study of engineering workers (n = 204) explored the validity of these mechanisms using sequential logistic regression. Analyses suggested that workers' ratings of the adequacy of the design and management of their work were related to their report of work-related musculoskeletal pain. However, the mechanisms appeared to be activated in certain conditions. The reporting of pain in the upper body was both biomechanically- and stress-related, whereas that in the lower body was only biomechanically-related. It is argued that the mechanism activated appeared to be determined by the anatomical location of the pain, and probably the variance shared between the different aspects of work design and management, on the one hand, and the mechanical load of the job, on the other.     

Media for the aerobic resuscitation of Campylobacter jejuni

The microaerophilic nature of Campylobacter jejuni has complicated its recovery from human and animal sources. In this study, enhancement of the growth and aerotolerance of C. jejuni ATCC 35921 in nutrient broth no. 2 (NB2) was investigated. The efficiency of recovery of C. jejuni in NB2 containing FBP (0.025% [each] ferrous sulfate, sodium metabisulfite, and sodium pyruvate), 5% laked horse blood, hemin, Oxyrase, or activated charcoal in an aerobic atmosphere was compared with that obtained under microaerophilic incubation. The shortest lag time (lamda) for cells grown aerobically was observed with NB2 supplemented with FBP, 5% laked horse blood, 0.01 g/liter of hemin, or 0.15 U/ml of Oxyrase. The efficacy of these media to resuscitate C. jejuni cells in late exponential phase, as well as cells subjected to stress induced by cold, heat, starvation, or acid, was determined in aerobic or microaerobic atmospheres. The h of cells grown aerobically in NB2 containing both FBP and blood was similar to that obtained in the same medium incubated in a microaerobic environment (P > 0.05). However, the X was longer during aerobic growth when low numbers of cells (approximately 1 log CFU/ml) in late exponential phase were used as the initial inoculum. The best recovery of stressed C. jejuni was observed in NB2 supplemented with FBP and blood and incubated aerobically. Enrichment in media incorporating FBP and 5% laked horse blood is a simple, convenient, and time-saving method to replace microaerophilic incubation methods for the resuscitation of C. jejuni.     

Human autoantibodies reveal titin as a chromosomal protein

Assembly of the higher-order structure of mitotic chromosomes is a prerequisite for proper chromosome condensation, segregation and integrity. Understanding the details of this process has been limited because very few proteins involved in the assembly of chromosome structure have been discovered. Using a human autoimmune scleroderma serum that identifies a chromosomal protein in human cells and Drosophila embryos, we cloned the corresponding Drosophila gene that encodes the homologue of vertebrate titin based on protein size, sequence similarity, developmental expression and subcellular localization. Titin is a giant sarcomeric protein responsible for the elasticity of striated muscle that may also function as a molecular scaffold for myofibrillar assembly. Molecular analysis and immunostaining with antibodies to multiple titin epitopes indicates that the chromosomal and muscle forms of titin may vary in their NH2 termini. The identification of titin as a chromosomal component provides a molecular basis for chromosome structure and elasticity.     

Expression of topoisomerase II, bcl-2, and p53 in three human brain tumor cell lines and their possible relationship to intrinsic resistance to etoposide

We characterized three human brain tumor cell lines (D54, HBT-20, and HBT-28) with respect to resistance to etoposide (VP-16), a topoisomerase II-reactive drug. All three cell lines were inherently resistant to VP-16 when compared to other human cell lines, with D54 showing the greatest resistance using colony formation assays. Resistance to VP-16 has been attributed to decreased drug uptake and changes in topoisomerase II; however, drug uptake and topoisomerase II protein levels (immunoblot) were no lower in D54 than in HBT-20 and HBT-28, cell lines relatively more sensitive to VP-16. More to the point, measurement of topoisomerase II-mediated DNA cleavage of cellular DNA after treatment with VP-16 showed that the topoisomerase II in these cells was active. These data indicate mechanisms other than those attributable to decreased drug uptake or altered topoisomerase II exist for clinical resistance to VP-16. VP-16-induced DNA cleavage has been associated with apoptosis in some cell lines; however, neither DNA laddering nor morphological changes characteristic of apoptosis were detected in these cell lines after treatment with VP-16. Bcl-2 and mutant p53 were present in these cells. Either of these conditions can prevent apoptosis and could explain a dissociation between the proximal mediator of VP-16-induced cytotoxicity (topoisomerase II-DNA complex formation) and cellular death.