The application of a sequential procedure with elimination as a method for the screening for metabolic diseases

A sequential classification procedure with early elimination, for the screening for metabolic diseases, is presented. Asymptotic properties of the procedure are derived in the Appendix and it is shown that the procedure is asymptotically distribution-free under certain assumptions, and asymptotically at least as efficient as a comparable fixed-sample procedure. With the use of data obtained from 36 mentally retarded patients, the procedure was evaluated by means of a bootstrap simulation. The procedure was then applied to this set of data, with satisfactory results and a considerable economy in observations.     

Increased permeability-oedema and atelectasis in pulmonary dysfunction after trauma and surgery: a prospective cohort study

We have developed a two-step procedure for preparing the skin before peripheral venous catheter (PVC) insertions. This procedure involves two successive swabbings with wipes soaked in alcoholic antiseptic. We investigated whether this two-step procedure was as effective and safe as the standard four-step procedure – washing with detergent, rinsing, drying, applying antiseptic – by carrying out a multicentre randomised equivalence study comparing the frequency of precursor signs of infection at the site of insertion for the two skin preparation procedures. The study was carried out over an eight-month period, and 248 PVC insertion sites were evaluated. The two-step procedure was used for 130 subjects and the standard procedure for 118. Taking into account all the confounding factors predisposing patients to the complications studied, the characteristics of the two groups of patients were found to be similar, with no significant differences noted. The incidence of precursor signs of infection was 11 % 24 hours after PVC insertion (27/248), 25 % at 48 hours (50/203) and at 29 % at 72 hours (34/119). Eleven patients had complications necessitating the withdrawal of the PVC: sensitivity of the insertion site, with redness and/or slight swelling and/or a palpable venous cord. No major complications were observed in this study. The frequency of local complications associated with PVCs reported in this study, whether simple or severe, was not affected by the skin preparation procedure used for PVC insertion (two-step or four-step procedure).     

Displacement imprinted polymer receptor analysis (DIPRA) for chlorophenolic contaminants in drinking water and packaging materials

The preparation of a molecularly imprinted polymer (MIP) for pentachlorophenol is described together with two alternative reporter derivatives for use in a displacement imprinted polymer receptor analysis (DIPRA) format procedure. In this procedure, alternative reporter molecules were rebound to the synthetic receptor sites and their displacement by the target analyte was employed as the basis of a simple procedure for the measurement of chlorophenols in water and packaging material samples. Water samples were extracted using the standard procedure (EPA 528) and a detection limit of 0.5 microg l(-1) was achieved using the DIPRA detection method, with good agreement between the displacement technique and GC-ECD analysis. A variety of packaging materials, extracted using a buffered detergent solution were also analysed using the DIPRA procedure and showed good agreement with GC results. In addition, investigation of the cross-reactivity of a range of pesticides and materials commonly encountered in environmental analysis indicated the procedure gave good discrimination between pesticides bearing a chlorophenolic moiety and other materials. The procedure is considered highly suitable for use as a rapid field-test method or for incorporation into a test kit device.     

A simultaneous procedure facilitates acquisition under an optimal interstimulus interval in artificial neural networks and rats

In a computer simulation, a neural network first received a simultaneous procedure, where the interstimulus interval (ISI) was 0 time-steps (ts). Output activations were near zero under this procedure. The network then received a forward-delay procedure where the ISI was 8 ts. Output activations increased to the near-maximum level faster than those of a control network that first received an explicitly unpaired procedure. Comparable results were obtained with rats that first received trials where a retractable lever was presented for 3s concurrently with access to water. Low-lever pressing was observed under this procedure. The rats then received trials where the lever was followed 15s after by water. Lever pressing appeared faster than a control group that received the 15-s ISI after an explicitly unpaired procedure. The model used in the simulation explains these results as connection-weight increments that promote little output activations in a simultaneous procedure, but facilitate acquisition in an optimal ISI.     

Application of Sequential Classification of Prey/Predator Ratio Test to Tetranychus urticae and Phytoseiulus persimilis System in Greenhouse Roses

A sequential sampling procedure for classifying the ratio of prey/predators developed by Nyrop (1988) was examined to implement for a biological control in the greenhouse roses. The procedure was combined with a sequential density classification procedure for use in monitoring a phytophagous mite, Tetranychus urticae Koch, and a phytoseiid predator, Phytoseiulus persimilis Athias-Henriot. This procedure was required four parameters: Means and variances for T. urticae and P. persimilis, correlation coefficient between densities of prey and predator and critical ratio of prey and predator. The parameter values used in this study were 0.725 for the correlation coefficient and 10 for the critical ratio. The variances for each species were estimated using a Taylor's power law model. The procedure is proven to be successfully applicable to T. urticae and P. persimilis system in greenhouse roses at two action threshold levels of 5 and 10 T. urticae per three-leaflet leave. The limitations and implementation of this procedure is also discussed.     

Simple preparation of parapoxvirus genome DNA for endonuclease analysis

We compared five methods for improved extraction of very-large parapoxvirus DNA from infected cells: (i) alkaline-lysis procedure followed by phenol extraction; (ii) modified Hirt procedure, which was a neutral lysis procedure followed by phenol extraction; (iii) Hirt procedure; (iv) method used for extraction of vaccinia virus DNA; and (v) standard procedure using virus purification with an ultracentrifuge and protease-sodium dodecyl sulfate-phenol treatment. The alkaline-lysis procedure was more rapid, inexpensive and simpler than the other methods. Moreover, with this method it is not necessary to prepare any special facilities, reagents and kits. Although the extracted DNA was still crude, we could reproducibly prepare viral DNA from 2 X 10(6) infected cells in less than 2 hr and it could be readily digested by restriction endonuclease. This method will aid rapid genetic classification of parapoxvirus.     

Comparison of Methods for Coccidioidomycosis Complement Fixation

A Laboratory Branch Task Force of the National Communicable Disease Center has proposed a standardized complement fixation procedure (LBCF) and an adaptation of this to microtitration techniques (MT) as uniform methods for performing complement fixation (CF) tests. A common procedure should make CF results from one laboratory more comparable to another. In addition, it would be preferable if the common procedure reproduced the titer levels of a testing procedure which is to be replaced, particularly when valid clinical interpretations have been derived from the latter. Replicated sets of sera were tested by the LBCF, MT, and the standard Smith CF procedure for coccidioidomycosis. Results with all three procedures were highly reproducible within an acceptable one-tube variation of a twofold dilution series, but the frequency of one-tube variations was greater with the MT method than with the other two. There was no statistical difference in the titers obtained with the Smith and LBCF procedures, but there was a significant difference when the MT results were compared to those with the Smith method. The LBCF method should be acceptable as a standardized and uniform CF procedure for coccidioidomycosis, subject to comparative testing between different laboratories.     

Isolated transmembrane helices arranged across a membrane: computational studies.

A computational procedure for predicting the arrangement of an isolated helical fragment across a membrane was developed. The procedure places the transmembrane helical segment into a model triple-phase system 'water-octanol-water'; pulls the segment through the membrane, varying its 'global' position as a rigid body; optimizes the intrahelical and solvation energies in each global position by 'local' coordinates (dihedral angles of side chains); and selects the lowest energy global position for the segment. The procedure was applied to 45 transmembrane helices from the photosynthetic reaction center from Rhodopseudomonas viridis, cytochrome c oxidase from Paracoccus denitrificans and bacteriorhodopsin. In two thirds of the helical fragments considered, the procedure has predicted the vertical shifts of the fragments across the membrane with an accuracy of -0.15 +/- 3.12 residues compared with the experimental data. The accuracy for the remaining 15 fragments was 2.17 +/- 3.07 residues, which is about half of a helix turn. The procedure predicts the actual membrane boundaries of transmembrane helical fragments with greater accuracy than existing statistical methods. At the same time, the procedure overestimates the tilt values for the helical fragments.     

Modified enrichment-serology procedure for detection of salmonellae in soy products.

A modified enrichment-serology (MES) procedure was used to reduce the time necessary for salmonella analysis. Naturally contaminated samples of soy products were preenriched in 1% proteose peptone for 6 h at 37 degrees C followed by inoculation into tetrathionate broth for 18 h at 37 degrees C. Two drops of the tetrathionate sample were inoculated into M broth. After incubation at 37 degrees C for 6 h, 0.85 ml of the mixture was formolized, and 0.1 ml of polyvalent H antiserum was added. After incubation in water bath at 50 degrees C for 1 h, the appearance of a typical floccular flagellar precipitate was observed in tubes positive for salmonellae. Over 3,000 samples were subjected to standard biochemical and serological procedures, and the results were compared with those of the MES method with a 96.7% correlation. Eleven of the samples (0.3%) were false-negative with the MES procedure, and 3% were false-negative with the U.S. Food and Drug Administration Bacteriological Analytical Manual procedure. The 3% negative samples by this latter procedure were subsequently found to be positive by the MES procedure. The MES procedure reduced the time required for salmonella analysis from 4 days to 32 h.     

A method to test large numbers of bovine semen samples for viral contamination and results of a study using this method

A procedure to test large numbers of semen samples for viral contamination is described. The procedure has the advantages of being simple to perform, sensitive and a relatively inexpensive method to test pooled semen samples, but it has the disadvantage of requiring serologically negative calves and sheep, isolation facilities to prevent environmental contamination during the testing procedure and relatively long times to obtain results. Using this in vivo procedure called the "Cornell Semen Test", it was found that of 40,000 ejaculates tested during a four year period none contained Infectious Bovine Rhinotracheitis Virus, Bovine Herpes Mammalitis Virus, Bovine Leukemia Virus nor Bluetongue Virus at infectious levels. The only virus that was found in a limited number of pools of semen was Bovine Virus Diarrhea Virus. It is recommended that if large volumes of pooled semen are to be tested for viral contamination that this procedure be used.     

The use of the maharanobis and modified distances for the improvement of simulation of glutamic acid production

A modified simulation procedure based on a statistical approach was investigated. The procedure predicts the time course of fed-batch culture for glutamic acid production by a temperature-sensitive strain of Brevibacterium flavum. The statistical approach requires only a data base of state points obtained in experiments, and not perfect identification of fermentation models. The simulation procedure is based on regression analysis to estimate specific rate parameters of system equations using the data points selected with reference to the Euclid distance. It was modified in that the data selection procedure included the use of the Maharanobis distance as well as a modified distance defined in this study. Simulation results using the modified procedure allow reasonable prediction of the time course of fed-batch culture for glutamic acid compared to that involving the Euclid distance alone.     

Simplified Procedure for Recovery of Lignin Acidolysis Products for Determining the Lignin-Degrading Abilities of Microorganisms

A simplified procedure for the identification and measurement of single-ring aromatic products of lignin acidolysis is described. The procedure employed a 6-h hydrolysis of spruce milled wood lignin in acidic dioxane at 87°C, followed by a series of organic extractions to recover acidolysis products which were quantified by gas chromatography of trimethylsilyl derivatives. Complex gel permeation chromatography procedures utilized by other workers were avoided in the modified procedure, but equivalent results were obtained. The simplified procedure was utilized to hydrolyze sound and actinomycete-decayed spruce milled wood lignins and was shown to be useful as a technique for the rapid screening of microorganisms for their ability to alter lignin.     

Properties of Mitochondria Prepared by Two Different Isolation Procedures From the Cotyledons of Germinating Bean Seedlings

Mitochondria from 1-day-old bean cotyledons were isolated bya ‘slow’ isolation procedure involving a wash andby a ‘rapid’ procedure. The mitochondria isolatedby the ‘rapid’ procedure were more tightly coupledthan those isolated by the ‘slow’ procedure. Anexogenous supply of cytochrome c or NAD was shown to improvethe activity of mitochondria isolated by the ‘slow’procedure, but not those isolated by the ‘rapid’procedure. The phosphorylative abilities of the latter weremuch greater than the former and were retained for longer periods.It was found that there was a leakage of NAD out of the mitochondria.     

Efficiency of a smooth desorption procedure for the purification of barley beta-amylase using immunoaffinity chromatography

Immunoaffinity chromatography was used for a one step purification procedure of beta-amylase from the G25 Sephadex gel filtrated fraction of whole barley protein extracts. The immunoglobulin G (IgG) fraction of an anti-barley beta-amylase immune serum was immobilized on Ultrogel. A gentle desorption procedure was used, combining distilled water elution with an interrupted elution. The quality of the purification was assayed by using cross immunoelectrophoresis with a polyspecific anti-barley protein immune serum. The extent of the damaging effect of this procedure was evaluated on the specific activity of the enzyme and on its polymorphism, as displayed by isoelectric focusing. The results underline the efficiency of the purification procedure and its low denaturing effect on the beta-amylase. This opens new possibilities for some aspects of the enzyme study and for the purification of other biologically active proteins.     

Normalizing upper trapezius EMG amplitude: Comparison of ramp and constant force procedures

The present study compared three procedures for normalization of upper trapezius surface electromyographic (EMG) amplitudes: (a) a ramp procedure (providing data in per cent of maximal voluntary contraction, MVC); (b) a constant force procedure based on two reference contractions (two-force procedure) (%MVC) and (c) a procedure expressing muscle activation in per cent of a reference voluntary electrical activity (%RVE). The study also evaluated the repeatability of the ramp and the RVE procedures and estimated the force exertion (%MVC) corresponding to the RVE. To illustrate the ergonomic effect of different normalization procedures, trapezius EMG during two work tasks was compared after normalization by the two-force and the RVE procedures. Fifteen subjects participated in the whole study. We found that force estimates obtained by the ramp procedure equation could be translated to force estimates obtained by the two-force procedure by the equation: %MVC_2force = − 0.6 + 0.9*%MVC_ramp, although with a considerable imprecision due to large inter-individual differences. In the ramp procedure, the intra-individual test-retest coefficient of variation (CV) depended on the force level; it was 45% at 5% MVC and 10% at 30% MVC. The CV of the RVE was 15%. The reference contraction used in the RVE procedure corresponded from 13–79% MVC (median 33%MVC). The load reducing effect of an ergonomic intervention was less obvious with the RVE procedure than with the two-force procedure due to a larger inter-individual variation. The advantages and disadvantages of the different procedures are discussed.     

Extraction of DNA from Phytophthora infestans Using QIAGEN Columns

High molecular weight DNA of Phytophthora infestans was extracted using a modification of the commercial QIAGEN column procedure. Both a 'maxi' and 'mini' procedure are described. The maxi procedure utilizes a QIAGEN-tip 500 column while the mini procedure utilizes a QIAGEN-tip 20 column. When fungal protoplasts were used as starting material from 9 g (fresh weight) of mycelium, nearly 500 μg of DNA in the size range of 20–200 kb was obtained and the product was successfully used in construction of a lambda genomic library. The modified QIAGBN method can replace the more timeconsuming, and expensive cesium chloride density gradient centrifugation for extraction of ultra-pure DNA from P. infestans .     

A micro liquid column chromatography procedure for twelve anticonvulsants and some of their metabolites

Solvent extracts of 50 μl volumes of serum were sufficient for the determination of twelve anticonvulsant drugs. The liquid chromatography procedure utilized a C-18 reversed-phase column and isocratic elution with 15% acetonitrile in water. No derivatization was required. Eluted anticonvulsants were detected by UV absorption at 195 nm and quantitated by drug—internal standard peak area ratios. The procedure provided linear working curves over the concentration range from 1 to 100 mg/l of drug in the serum. The procedure for serum provided recoveries of the drugs from 92 to 101%. Within-day precision was about 4% and day-to-day precision was about 6.5%. The procedure has been applied to urine samples to facilitate bioavailability studies. Data are also given for several metabolites. There is a discussion of many practical aspects of the procedure to improve the reliability of the results.     

A one-step technique for the subcellular fractionation of total cell homogenates

A procedure was developed for the rapid, analytical subcellular fractionation of entire homogenates from the Chinese hamster ovary and HeLa cell lines. The procedure avoids a nuclear sedimentation step and the losses that accompany such a step. A key to the development of this procedure was the addition to homogenates of either micrococcal nuclease or DNase I. Nuclease-treated homogenates were fractionated on self-forming Percoll gradients. The entire procedure from cell harvesting through collecting gradient fractions took only 2.5 h. The position of marker enzymes in the gradient fractions indicated clear resolution of plasma membranes, Golgi apparatus, endoplasmic reticulum, and lysosomes. This procedure should facilitate many studies requiring subcellular fractionation of cultured cells.     

Does it matter what a hospital is “high volume” for? Specificity of hospital volume-outcome associations for surgical procedures: analysis of administrative data

Objective To determine whether the improved outcome of a surgical procedure in high volume hospitals is specific to the volume of the same procedure.Design and setting Analysis of secondary data in Ontario, Canada.Participants Patients having an oesophagectomy, colorectal resection for cancer, pancreaticoduodenectomy, major lung resection for cancer, or repair of an unruptured abdominal aortic aneurysm between 1994 and 1999.Main outcome measures Odds ratio for death within 30 days of surgery in relation to the hospital volume of the same surgical procedure and the hospital volume of the other four procedures. Estimates were adjusted for age, sex, and comorbidity and accounted for hospital level clustering.Results With the exception of colorectal resection, 30 day mortality seemed to be inversely related not only to the hospital volume of the same procedure but also to the hospital volume of most of the other procedures. In some cases the effect of the volume of a different procedure was stronger than the effect of the volume of the same procedure. For example, the association of mortality from pancreaticoduodenectomy with hospital volume of lung resection (odds ratio for death in hospitals with a high volume of lung resection compared with low volume 0.36, 95% confidence interval 0.23 to 0.57) was much stronger than the association of mortality from pancreaticoduodenectomy with hospital volume of pancreaticoduodenectomy (0.76, 0.44 to 1.32).Conclusion The inverse association between high volume of procedure and risk of operative death is not specific to the volume of the procedure being studied.