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PubMedDate not supplied

The single-point method of dosage prediction: pharmacokinetic basis and method optimization.

Based on the principle of superposition an expression has been established relating a drug concentration at steady-state to a concentration after a single dose. This relationship applies for drugs with linear pharmacokinetics given at equal dosage intervals and it is independent of the route of administration. The relationship provides theoretical justification for the single-point method of dosage prediction reported in the literature. The test conditions in the method can therefore be optimized and the limits of the method defined. The expression can also be used for individualized prediction of maintenance dose after estimation of drug half-life in the patient with no limit to half-life values to which it can be applied.

Half-Life↗
PubMed1984

Accurate, wide-range, automated, high-performance liquid chromatographic method for the estimation of octanol/water partition coefficients I: Effect of chromatographic conditions and procedure variables on accuracy and reproducibility of the method.

A high-performance liquid-chromatographic (HPLC) procedure is reported for estimation of the logarithm of the octanol/water partition coefficient, log P(o/w). This automated log P(o/w) measurement (ALPM) circumvents many inherent difficulties with the shake-flask method, yet gives high reproducibility and excellent overall correlation with shake-flask results. Partition coefficients for numerous structurally diverse chemicals, ranging from approximately 0 to approximately 8 log P(o/w) units, can be determined; however, values for zwitterionic compounds cannot be obtained. Additional advantages of ALPM include lower cost and greater safety when compared with other HPLC or shake-flask procedures. Chromatographic conditions (i.e., flow rate and temperature) and variables (i.e., column length and solvent composition) affecting this method are discussed in detail. ALPM may also find application in quality control of HPLC columns, qualitative-quantitative analysis, and in computer-controlled method development and analysis.

Chemical Phenomena↗
PubMed1984

Determination of heparin activity by a new laser nephelometric method and comparison to the USP method.

A new method for the determination of heparin activity in solutions has been developed, based on the increase in light scattering observed during the clotting of plasma. The recalcification clotting time (RCT) of sheep plasma is measured in the presence of heparin, using a laser nephelometer. The activity of heparin in the sample is determined from a standard curve of the logarithm of RCT versus heparin activity. The results indicate that this method is simpler, faster, and more reproducible than the current USP grading method.

Animals↗
PubMed1996

Candidate reference method for determining serum cortisol based on isotope dilution-gas chromatography/mass spectrometry using heptafluorobutyrilation as derivatization method.

We present a new candidate reference method for determining cortisol in serum. The method is based on isotope dilution-gas chromatography/mass spectrometry and makes use of derivatization with heptafluorobutyric anhydride and selected ion monitoring at m/z 489 and 491. A detection limit of 0.08 pmol (30 pg) was achieved. Twenty-four structurally related steroids were tested for interference and found negative. Verification of the analytical quality specifications was done from measurement in two laboratories of the certified reference materials 192 and 193 of the Bureau Communautaire de Référence and a number of commercial quality control materials. The maximum systematic error was estimated to be 1.0% and the mean imprecision was 1.0%. The total error was lower than 2.05%. The method was applied for target-setting in external quality assessment and internal accuracy control and for measurement of patient samples.

Fluorocarbons↗
PubMed2001

Gene transfer methods for CNS organotypic cultures: a comparison of three nonviral methods.

Organotypic slice cultures from postnatal day 12 mouse cerebellum were transfected using three nonviral methods: biolistics (gene gun), lipotransfection, and electroporation. The plasmid transferred, pHD17-25Q-GFP, encoded a fusion protein with a green fluorescent protein (GFP) component. Optimal conditions for both lipotransfection and electroporation are the same as those previously found in live animal models. Electroporation (26 +/- 6) and biolistics (34 +/- 4.4) provide a better rate of transfer than lipotransfection (15 +/- 2.2) in slice cultures and are comparable to each other. Each of the transfer methods produced positive signals in a heterogeneous population of glial and neuronal cells. These data provide a base for optimal transfection of slice cultures, allowing the development of therapeutic constructs, and support the idea that successful refinement of nonviral delivery methods for in vivo use is possible using brain slice cultures.

Animals↗
PubMed2006

Positive selective brain cooling method: a novel, simple, and selective nasopharyngeal brain cooling method.

Brain damage is worsened by hyperthermia and prevented by hypothermia. Conventional hypothermia is a non-selective brain cooling method that employs cooling blankets to achieve surface cooling. This complicated method sometimes induces unfavorable systemic complications. We have developed a positive selective brain cooling (PSBC) method to control brain temperature quickly and safely following brain injury. Brain temperature was measured in patients with a ventriculostomy CAMINO catheter. A Foley balloon catheter was inserted to direct chilled air (8 to 12 L/min) into each side of the nasal cavity. The chilled air was exhaled through the oral cavity. In most patients, PSBC maintained normal brain temperature. This new technique provides quick induction of brain temperature control and does not require special facilities.

Adult↗
PubMed1984

Methods for evaluating the taste of paediatric formulations in children: a comparison between the facial hedonic method and the patients' own spontaneous verbal judgement.

The aim of the study was to evaluate two essentially different methods of assessing differences in children's taste preferences with regard to five different paediatric penicillin formulations. The study was performed with a parallel group design comparing five groups. A taste evaluation was recorded in 103 children with upper respiratory tract infections after a single therapeutic test dose. First the patient's own spontaneous verbal judgement was recorded then a judgement was arrived at using a hedonic scale of facial expressions. Both judgements were passed immediately and also 3-4 minutes after the test dose. In the children who were 6 years of age or younger, a better discrimination of taste differences between formulations was achieved by using the patients' own spontaneous verbal judgements instead of the facial hedonic method. Both methods seem appropriate in older children, but the hedonic scale is preferable since its use implies a more standardised procedure.

Ampicillin↗
PubMed1982

Comparison of an HPLC method with a RIA, EMIT and FIA method for the assay of serum gentamicin with extensive statistical evaluation.

A high performance liquid chromatography (HPLC) assay, a radioimmunoassay (RIA), an enzyme immunoassay (EMIT) and a fluorescence immunoassay (FIA) method for assaying serum gentamicin were compared in terms of accuracy and precision. Spiked human serum samples in the range of 0-11.6 mg.1(-1) gentamicin were used in all the tests. Regression analysis and analysis of variance were performed. The Performance Index (PI) was used to qualify the different methods. Other aspects of performance were also compared: simplicity, speed, cost, application in relation to workload. After extensive statistical evaluation the FIA method gives the best results.

Chromatography, High Pressure Liquid↗
PubMed1996

A comparison of a Bayesian population method with two methods as implemented in commercially available software.

In this paper we describe and discuss three specific estimation procedures that are available within commercially available population software packages. The first version of NONMEM (l) was released in 1979 and later versions are the standard analysis tools in both industry and academia. Recently, two commercially available pieces of software have become available. PPHARM was released during 1994 and POPKAN was released in 1995. We provide descriptions and critique the FOCE method within NONMEM, the two-step algorithm within PPHARM and the Markov chain Monte Carlo method that is utilized by POPKAN. We use simulated data generated from a monoexponential model to evaluate the parameter estimation capabilities of these methods within the three software tools. In particular we investigate the effect on parameter estimation of increasing both interindividual and intraindividual variability.

Bayes Theorem↗
PubMed2003

Temperature measurement in intensive care patients: comparison of urinary bladder, oesophageal, rectal, axillary, and inguinal methods versus pulmonary artery core method.

OBJECTIVE: Comparisons of urinary bladder, oesophageal, rectal, axillary, and inguinal temperatures versus pulmonary artery temperature. DESIGN: Prospective cohort study. SETTING: Intensive Care Unit of a University-Hospital. PATIENTS: Forty-two intensive care patients requiring a pulmonary artery catheter (PAC). INTERVENTION: Patients requiring PAC and without oesophageal, urinary bladder, and/or rectal disease or recent surgery were included in the study. Temperature was simultaneously monitored with PAC, urinary, oesophageal, and rectal electronic thermometers and with axillary and inguinal gallium-in-glass thermometers. Comparisons used a Bland and Altman method. MEASUREMENTS AND MAIN RESULTS: The pulmonary arterial temperature ranged from 33.7 degrees C to 40.2 degrees C. Urinary bladder temperature was assessed in the last 22 patients. A total of 529 temperature measurement comparisons were carried out (252 comparisons of esophageal, rectal, inguinal, axillary, and pulmonary artery temperature measurements in the first 20 patients, and 277 comparisons with overall methods in the last patients). Nine to 18 temperature measurement comparisons were carried out per patient (median = 13). The mean differences between pulmonary artery temperatures and those of the different methods studied were: oesophageal (0.11+/-0.30 degrees C), rectal (-0.07+/-0.40 degrees C), axillary (0.27+/-0.45 degrees C), inguinal (0.17+/-0.48 degrees C), urinary bladder (-0.21+/-0.20 degrees C). CONCLUSION: In critically ill patients, urinary bladder and oesophageal electronic thermometers are more reliable than the electronic rectal thermometer which is better than inguinal and axillary gallium-in-glass thermometers to measure core temperature.

Aged↗
PubMed2003

The approximate planimetric method: a simple, rapid and reliable method for estimation of lesion size in acute ischemic stroke.

Magnetic resonance imaging is increasingly used in stroke trials for early diagnosis and follow-up of lesion size. Since volumetric measurement remains a laborious and time-consuming task, a rapid and reliable method for the assessment of lesion size has been developed and validated in diffusion weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR) sequences. These were serially obtained in 40 patients less than 8 h after the onset of symptoms of a middle cerebral artery territory stroke (day 1), as well as on days 3 and 18. For each of 16 (DWI) or 20 (FLAIR) transverse sections obtained on each occasion, lesion size was estimated as a percentage of the total hemisphere. Percentage values from all sections were summed up and expressed as arbitrary units. Results obtained using this approximate planimetric method (APM) were compared with those from a standard volumetric approach. Lesion volumes as determined by both methods were highly correlated (DWI: r = 0.966, FLAIR: r = 0.979, p < 0.001). To conclude, the APM is simple, rapid and reliable for the estimation of lesion size in acute ischemic stroke. It can be recommended for broader application in clinical trials.

Anthropometry↗
PubMed2003

Comparison of the sodium dodecyl sulfate-sodium hydroxide specimen processing method with the C18-carboxypropylbetaine specimen processing method using the MB/BacT liquid culture system.

The ability of physicians to diagnose tuberculosis is impacted by the use of smear and culture techniques combined with specimen processing methods. The objective of this study was to evaluate the effects of specimen processing on smear and culture sensitivity by comparing the specimen processing method that uses C(18)-carboxypropylbetaine with the method that combines sodium dodecyl sulfate and sodium hydroxide. A total of 1,201 specimens were entered into this study. Specimens were split approximately equally such that one-half of each specimen was processed with sodium dodecyl sulfate-sodium hydroxide, while the other half was processed with C(18)-carboxypropylbetaine. All sediments were subjected to acid-fast staining and then analyzed using the MB/BacT liquid culture system (bioMérieux, France) and solid media. The sensitivity of smear following processing with sodium dodecyl sulfate-sodium hydroxide and C(18)-carboxypropylbetaine was 61.2% and 58.6% (P>0.05), respectively, while the specificities were identical (99.7%). The sensitivity of culture was 84.2% and 96.1% (P<0.05), respectively. The time to detection in the MB/BacT liquid culture system was 13.2+/-5.6 and 15.0+/-8.8 days (P>0.05), respectively, and 20.0+/-7.6 and 15.7+/-8.9 days (P<0.05), respectively, on solid media. The contamination rates in the MB/BacT system were 0.8% and 8.7%, respectively, whereas the contamination rates on solid media were 2.6% and 4.3%, respectively. C(18)-carboxypropylbetaine specimen processing was less labor-intensive than sodium dodecyl sulfate-sodium hydroxide processing and improved the ability of laboratory staff to detect the presence of mycobacteria by culture.

Bacteriological Techniques↗
PubMed1989

A simple colorimetric assay method for pyrophosphate in the presence of a 1000-fold excess of orthophosphate: application of the method to the study of pyrophosphate metabolism in mitochondria.

A sensitive colorimetric method for the assay of inorganic pyrophosphate with excess of orthophosphate is described. The principle of this method lies in the formation of phosphomolybdate and PPi-molybdate complexes with subsequent extraction of the phosphomolybdate complex by organic solvents and reduction of the PPi-molybdate complex by dithiothreitol and Eikonogen. The sensitivity of the method was from 5 to 120 nmol of PPi in a 2.0-ml sample.

Animals↗
PubMed1985

Entorhinal and prepiriform cortices of the European hedgehog. A histochemical and densitometric study based on a comparison between Timm's sulphide silver method and the selenium method.

The Timm and selenium staining techniques, based on silver amplification of endogenous zinc, produce an electron-dense precipitate in boutons. The staining characteristics of the two methods were compared by examining two allocortical regions, prepiriform cortex and entorhinal cortex, in the brain of the European hedgehog. In the 3 layers of prepiriform cortex and the 6 layers of entorhinal cortex the methods revealed sublayers, which allows a precise delimitation of areas 28M, 28L, a short transition zone, and the prepiriform cortex. The lamination of the entorhinal cortex of the hedgehog is similar to that found in the rat, but appears less distinct. This may point to a lower degree of afferent organization. For light microscopical investigations, the selenium technique appears superior to Timm's method because it produces a more distinct zonation pattern.

Animals↗
PubMed1985

Effects of cryopreservation on human lymphocyte functions: comparison of programmed freezing method by a direct control system with a mechanical freezing method.

The effects of cryopreservation with a new-type programmed freezer (TNP-82) were examined on natural killer (NK) activity and cell recovery of lymphocytes. This instrument is controlled by a sensor which directly detects the temperature in the samples, enabling easy setting of the temperature curve. Comparing results obtained by the new method to those from a less sophisticated mechanical method, cell recovery after cryopreservation was improved (95.3%) in the new compared to the older (about 80%) method. Furthermore, NK activity, percentage of Leu7+ cells and other lymphocyte functions were unaltered.

Antigens, Surface↗
PubMed1985

Rapid methods for counting mycobacteria--comparison of methods for extraction of mycobacterial adenosine triphosphate (ATP) determined by firefly luciferase assay.

A comparison of 5 different methods of extraction of adenosine 5'-triphosphate (ATP) from mycobacterial cells was carried out using Mycobacterium bovis, BCG as a model. ATP was measured using the luciferin-luciferase bioluminescence reaction. Boiling buffer extraction was the best method. The amount of ATP extracted correlated with the number of colony forming units over a wide range of count. Although great sensitivity in terms of number of bacilli detectable was not achieved the method was rapid and appears suitable for drug sensitivity testing of tubercle bacilli.

Adenosine Triphosphate↗
PubMed1988

Method for evaluating mutagenicity of water. I. A new method of preparing samples for mutagenicity test.

A sample preparation method for a convenient and quantitative mutagenicity test of water was developed using two new superior resinous adsorbents. One, CSP800, is a small particle size and highly porous polystyrene resin, and the other, CHPA25, is a small particle size and highly porous anion-exchange resin. CSP800 adsorbed more nonionic compounds from water than conventional resins, and CHPA25 adsorbed anionic compounds not adsorbed by conventional resins. Sample water (10 l) at pH 5 was fed at 550 ml h-1 into two columns in series, one containing 5 ml of CSP800 and the other 2 ml of CHPA25. The adsorbed substances were subsequently desorbed by DMSO from CSP800 and by 4 N NaNO3 from CHPA25, at 10 ml h-1. Various organic substances, which were measured by different indices such as total trihalomethanes (THM), total organic halogen (TOX) and the absorbence at 260 nm, could be recovered by this method much more efficiently and conveniently than by conventional methods.

Chromatography, Ion Exchange↗
PubMed1989

A method for exposing primates to marihuana smoke that stimulates the method used by human marihuana smokers.

A method was developed for exposing rhesus monkeys to marihuana smoke under conditions simulating those used by human marihuana smokers. An ADL II smoking machine was used to generate puffs of smoke of constant volume from marihuana or placebo cigarettes at a constant rate. The outlet of the smoking machine was connected by Tygon tubing to an airtight face mask covering the monkey's nose and mouth. The monkey was seated in an airtight Plexiglas chamber with only its head protruding. When a puff of smoke was generated, a vacuum was imposed on the chamber causing the monkey to inhale deeply and hold its breath. After 6 seconds, the vacuum was removed and the monkey was allowed to exhale and breathe fresh air freely until the next puff. Delivery of smoke to the monkey by this method was more efficient than allowing the monkey to voluntarily inhale the smoke. The method was used in acute dose-effect experiments and, subsequently, in long-term experiments. It may be useful with other animal species and for efficiently delivering other airborne substances of abuse.

Animals↗