A high-performance system for automation of the polymerase chain reaction.

A high-performance PCR system has been developed which reduces the time required for PCR, increases the throughput, reduces reagent consumption and ensures reproducibility of amplification. Integration of sophisticated temperature control with optimally designed vessels has resulted in an amplification system which produces unique benefits. These include rapid amplification, the elimination of the need for oil, even for small volumes, and a microplate format which provides liquid handling automation benefits.

A high-sensitivity electrochemiluminescence-based detection system for automated PCR product quantitation.

A high-sensitivity nonisotopic system has been developed for post-PCR product detection. The probe-based detection system exploits a chemiluminescent reaction that takes place on the electrode surface in an electrochemical cell. The detection system incorporates a biotin-streptavidin capture reaction onto a solid support that permits fast post-PCR product detection at the attomole level. The system precision is within 5% relative standard deviation over a linear dynamic range of greater than three orders of magnitude. In this paper, the principles and features of the electrochemiluminescent-based detection system, together with its application to PCR product quantitation, are described in detail.

Detection of bacterial mRNA using polymerase chain reaction.

A method was developed for the detection of bacterial mRNAs using reverse transcriptase followed by the polymerase chain reaction (PCR) and Southern blot analysis. The method involves brief inhibition of protein synthesis with chloramphenicol, followed by reverse transcription, PCR amplification of cDNA and Southern blot hybridization. Detection of mRNAs by reverse transcription-PCR-Southern blot analysis is orders of magnitude more sensitive than Northern blot hybridization.

Prospective economic evaluation accompanying a trial of GM-CSF/IL-3 in patients undergoing autologous bone marrow transplantation for Hodgkin's and non-Hodgkin's lymphoma. IL-3 BMT Study Team.

Our objective was to assess the economic impact of a new cytokine therapy that was being compared to standard therapy as supportive care in patients receiving autologous bone marrow transplantation for treatment of lymphoma. We performed an economic study accompanying a multicenter, randomized, controlled clinical trial in academic medical centers. One hundred and fifteen patients consented to participate in a parallel economic study of a randomized controlled trial of sequential IL-3 followed by GM-CSF vs GM-CSF alone after autologous bone marrow transplantation. We measured costs and quality-adjusted survival over a 13-month follow-up period. For the 13-month study period, the total cost estimates were $79892 (95% CI $69343 to $90544) for patients receiving GM-CSF alone and $89651 (95% CI $79769 to $102114) for patients receiving IL-3/GM-CSF. The difference was not statistically significant. During the 13-month study period, the total number of quality-adjusted life-months in the GM-CSF arm was 6.67 (95% CI 5.75 to 7.56) months, while the total number of quality-adjusted life-months in the IL-3 arm was 6.26 (95% CI 5.34 to 7.15) months. The difference in quality-adjusted life-months between the two treatment arms was not statistically significant. We conclude that economic analysis of a phase III clinical trial of IL-3/GM-CSF compared with GM-CSF alone showed no significant effect of IL-3 on the costs of care for patients undergoing bone marrow transplantation for a period of up to 13 months after the procedure. This study demonstrates the feasibility of prospective economic evaluation within phase III trials of new cancer therapies. Data from this type of economic protocol could be used to help physicians, patients and managed care organizations understand the effect of new treatments from both a clinical and an economic perspective.

Evaluation of EMIT methods for the determination of the five major antiepileptic drugs on an automated kinetic analyser.

We have evaluated the performance of enzyme-multipled immunoassay methods for the five major antiepileptic drugs on an automated system, the Perkin-Elmer Model KA-150 Kinetic Analyzer. The precision in the normal duplicate mode was found to be in the range of 6% to 10% for all five tests over a typical working day. All EMIT methods were compared to gas-liquid chromatographic procedures and, in addition, the phenytoin and phenobarbital assays were compared to a liquid-chromatographic method. The phenytoin assay was also compared to RIA and to a manual spectroscopic method. In general, most of the comparison studies resulted in acceptable correlation, although one gas chromatographic method did not correlate very well with the phenytoin and phenobarbital immunoassays.

Preparation of pentachlorophenol derivatives and development of a microparticle-based on-site immunoassay for the detection of PCP in soil samples.

Pentachlorophenol (PCP) is used as a herbicide in agriculture and as an insecticide for termite control. Because of the apparent hazard associated with its usage, there is a need for an efficient and economic on-site screening method. A 5-min on-site test has been developed for the detection of PCP based on the OnTrak format, a successful Roche on-site test format for drugs of abuse, utilizing the principle of latex agglutination immunoassay. The test detects 1 ppm of PCP in soil samples.

Otimum kinetic enzymatic procedures for glucose and triglycerides in plasma and serum.

I describe optimum kinetic procedures for measuring glucose and triglycerides in plasma and serum by enzymatic techniques. Glucose was measured by the hexokinase method at a 1000-fold sample dilution. Absorbance and concentration are linearly related for concentrations up to 4 g/liter. Results are reproducible to about 25 mg/liter (standard error). Comparisons between the kinetic glucose method described here and an automated o-toluidine and a manual end-point method showed no apparent bias between the methods; correlation coefficients were 0.998 and 0.991, respectively. Triglycerides (triacylglycerols) were measured in a fully enzymatic system by measuring free glycerol after hydrolysis with lipase. Absorbance and concentration are linearly related to greater than 2.5 g/liter at a 300-fold sample dilution. Repeatability was about 30 mg/liter (standard error). Compared with a manual method, the correlation coefficient was 0.978, with a slope of 0.93.

Making enzymatic methods optimum for measuring compounds with a kinetic analyzer.

Kinetic enzymatic methods for analysis of substrates can be made optimum for a sensitive photometric analyzer by adjusting the activity of the triggering (catalyzing) enzyme so that the reaction rate is maximum at the time of measurement. tat this optimum activity, the exponential time constant for exhaustion of substrate equals the time between triggering and rate measurement. The scale factor (defined as measured activity divided by sample concentration in the reaction mixture) is the same for all tests. Sensitivity to substrate concentration is predictable from instrumental absorbance uncertainty and molar absorptivity of the absorbing species. These predictions from Michaelis theory were verified experimentally for pyruvate and lactate triggered with lactate dehydrogenase, for glucose triggered with hexokinase, and for triglycerides triggered with glycerol kinase, the reaction rate being measured 30 s after triggering. Sensitivities of 1.5 times 10(-7) mol/liter were achieved. Serum diluted 1000-fold and analyzed for glucose gave a repeatability of 25 mg/liter with linearity to 4.0 g/liter. Samples diluted 300-fold and analyzed for triglycerides gave 30 mg/liter repeatability, with linearity to concentrations exceeding 3.0 g/liter.

Automated turbidimetry of amylase activity by use of a discrete kinetic analyzer.

We adopted an automated turbidimetric rate method for determining amylase activity to the KA-150 Kinetic Analyzer. In the method, an insoluble amylopectin substrate is used with activity determined by the rate of decrease in turbidity. Run-to-run CV for 59 samples with activities up to 400 units (arbitrary amylase units per 100 ml of sample) was 2.8%. A comparison with a similar method, performed by nephelometry, for 104 sera, showed a correlation coefficient (r) of 0.992, with a slope of 1.02. In an additional comparison with an amyloclastic method, for 52 sera r was 0.997, with a slope of 1.01. Day-to-day precision for control sera with activities near the upper limit of normal (279 and 216 units) averaged 2.5% during two months. Measured and calculated activity were linearly related to well above the upper limit of normal (normal range, 60-200 arbitrary units), showing a deviation from linearity of about 10% at 450 units. Commercial reagents available for the Perkin-Elmer Model 91 Amylase Lipase Analyzer can be used with the KA-150.

A prospective economic evaluation of basiliximab (Simulect) therapy following renal transplantation.

BACKGROUND: Immunoprophylaxis with basiliximab (Simulect), an anti-interleukin-2-receptor (anti-IL-2R; CD25) chimeric monoclonal antibody, has been demonstrated to significantly reduce the incidence of acute cellular rejection in adult renal allograft recipients (32% vs. placebo, p < 0.01). METHODS: An economic evaluation was conducted as part of a U.S. multi-center, randomized, double-blind, placebo-controlled clinical trial comparing basiliximab plus dual immunosuppressive therapy (cyclosporine modified [Neoral] and corticosteroids) to dual therapy alone. Healthcare resources utilized by the 346 subjects in the 'intent-to-treat' population were prospectively collected over the 1-yr study period. Direct medical costs were determined for all hospitalizations, outpatient provider visits, procedures (excluding the initial transplant procedure), laboratory and diagnostic tests, and immunosuppressants, including basiliximab when administered. RESULTS: Total first-year medical costs were lower for the basiliximab group than for the placebo group ($28 927 vs. $32 300, difference = $3373). although this difference was not statistically significant. First-year hospital costs for treating acute rejection were also lower for the basiliximab group ($9328 vs. $10761, difference = $1433); however, this difference did not achieve statistical significance. Importantly, the efficacy analysis demonstrated a significant reduction in the incidence of acute rejection (38 vs. 55%, p < 0.01) in the basiliximab arm, and this was accomplished without increasing the overall cost of care. Fewer basiliximab-treated patients (8 vs. 15%,, p = 0.03) were hospitalized. This observation suggested less serious illness and reduced treatment costs among basiliximab-treated patients, because the overall incidence of infection was similar between the groups. The adverse event profile of patients receiving basiliximab was clinically and economically indistinguishable from that of those treated with placebo. CONCLUSION: Induction immunosuppression with basiliximab, combined with cyclosporine modified and corticosteroids, was therapeutically beneficial and contained medical costs during the initial post-transplant year.

Polymerase chain reaction-gene probe detection of microorganisms by using filter-concentrated samples.

To detect low levels of microorganisms in environmental samples by using polymerase chain reaction (PCR)-gene probe detection, samples were concentrated by filtration. Fluoropore (Millipore Corp.) filters were compatible with PCR DNA amplification, whereas various other filters including nitrocellulose and cellulose acetate filters inhibited PCR amplification. By concentrating cells on Fluoropore filters and releasing the DNA by freeze-thaw cycling, PCR DNA amplification could be performed without removing the filter. Concentration with Fluoropore FHLP and FGLP filters permitted the detection of single cells of microorganisms in 100-ml samples by PCR-gene probes.

Detection of Escherichia coli and Shigella spp. in water by using the polymerase chain reaction and gene probes for uid.

A method was developed for the detection of the fecal coliform bacterium Escherichia coli, using the polymerase chain reaction and gene probes, based on amplifying regions of the uid gene that code for beta-glucuronidase, expression of which forms the basis for fecal coliform detection by the commercially available Colilert method. Amplification and gene probe detection of four different regions of uid specifically detected E. coli and Shigella species, including beta-glucuronidase-negative strains of E. coli; no amplification was observed for other coliform and nonenteric bacteria.

Quality of life in persons with irritable bowel syndrome: development and validation of a new measure.

How irritable bowel syndrome (IBS) and its treatment affect quality of life (QOL) is important. To develop a quality-of-life measure specific to irritable bowel syndrome, items were generated using a conceptual model and qualitative interviews with persons diagnosed using the Rome criteria. Symptom frequency and bothersomeness indices were created. Psychometric evaluation methods involved an initial cross-sectional survey followed by a repeat survey. The resulting 34-item measure demonstrated high internal consistency (Cronbach's alpha = 0.95) and high reproducibility (ICC = 0.86) with average time of seven days (SD = 1). For discriminant validity: number of symptoms (P < 0.05), self-reported severity of symptoms (P < 0.001), and the functional bowel disorder severity index (P < 0.001) significantly predicted IBS-QOL scores. Convergent validity and analyses confirmed predictions that scores are more closely related to psychological well-being (0.45) than to function (0.36). We conclude this measure meets established psychometric criteria for reliability and validity; testing of its responsiveness is warranted.

Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay.

Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoassay, enzyme immunoassay, and liquid chromatography. The essay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods.

Detection of coliform bacteria in water by polymerase chain reaction and gene probes.

Polymerase chain reaction (PCR) amplification and gene probe detection of regions of two genes, lacZ and lamB, were tested for their abilities to detect coliform bacteria. Amplification of a segment of the coding region of Escherichia coli lacZ by using a PCR primer annealing temperature of 50 degrees C detected E. coli and other coliform bacteria (including Shigella spp.) but not Salmonella spp. and noncoliform bacteria. Amplification of a region of E. coli lamB by using a primer annealing temperature of 50 degrees C selectively detected E. coli and Salmonella and Shigella spp. PCR amplification and radiolabeled gene probes detected as little as 1 to 10 fg of genomic E. coli DNA and as a few as 1 to 5 viable E. coli cells in 100 ml of water. PCR amplification of lacZ and lamB provides a basis for a method to detect indicators of fecal contamination of water, and amplification of lamB in particular permits detection of E. coli and enteric pathogens (Salmonella and Shigella spp.) with the necessary specificity and sensitivity for monitoring the bacteriological quality of water so as to ensure the safety of water supplies.

Identification of the factors affecting the rate of deactivation of hypochlorous acid by melatonin.

It has been found that melatonin reacts rapidly with hypochlorous acid in phosphate-buffered, ethanol-water solutions to produce 2-hydroxymelatonin. The rate law, d[2 - HOMel]/dt - kHOCl[Mel][HOCl] - kOCl-[Mel][OCl-], was obtained. At 37 degrees C and at a water concentration of 23.5 M, kOCl- = 6.0 x 10(2) L. mol-1. s-1, and kHOCl was found to be a function of the water concentration, kHOCl = 11 +/- 3 L3. mol-3. s-1. [H2O]2, indicating that the availability of water at the site of the reaction plays a significant role. The part that the structural components of melatonin play in determining the reaction pathway was examined by comparing the rate of deactivation of HOCl by melatonin to that of the model compounds indole, 5-methoxyindole, and 3-methylindole. The relative reactivity is explained in terms of steric and electronic effects, and it was found that the presence of the substituent at the 3-position influences the nature of the oxidation product. Melatonin and 3-methylindole yielded hydroxylated products, whereas indole and 5-methoxyindole produce chlorinated products.

Multiplex PCR amplification and immobilized capture probes for detection of bacterial pathogens and indicators in water.

Detection of pathogens (Legionella species) and indicator bacteria (coliform bacteria) was achieved by multiplex (simultaneous) PCR amplification of diagnostic gene sequences and by hybridization to immobilized poly-dT-tailed capture probes using a dot- or slot-blot approach. Complex manipulations of primer concentrations and staggered additions of primers were required in order to achieve equal amplification of multiple genes. Multiplex PCR amplification of two different Legionella genes, one specific for L. pneumophila (mip) and the other for the genus Legionella (5S rRNA), was achieved by staggered amplification. Multiplex PCR amplification using differing amounts of primers specific for lacZ and lamB genes permitted the detection of coliform bacteria and those associated with human faecal contamination, including the indicator bacterial species E. coli and enteric pathogens Salmonella and Shigella. Hybridization of biotin-labelled amplified DNA, in which the biotin was incorporated during PCR amplification from biotinylated-dUTP, to immobilized 400-dT-tailed capture probes permitted specific and sensitive detection of target gene sequences. The sensitivity of colorimetric detection achieved by PCR amplification of target DNA was at a level equivalent to 1-2 bacterial cells, which is the same level of sensitivity obtained with radioactive detection. The simultaneous amplification of several genes and hybridization to immobilized capture probes with colorimetric detection is an effective, efficient and rapid detection method for various human bacterial pathogens.