Plasmonic nanocone arrays for rapid and detailed cell lysate surface enhanced Raman spectroscopy analysis.

In this work, we develop, fabricate, and characterize a plasmonic nanocone array surface enhanced Raman spectroscopy (SERS) substrate with a uniform enhancement factor on the micron scale for qualitative and quantiative cell and cell lysate analysis. This work demonstrates how SERS substrates can be used as cell-based biosensors given that the enhancement factor of the substrate is sufficient for Raman detection and that the uniformity is high over the applicable surface area. These requirements allow accurate and quantitative comparisons between nonuniform samples under varying biochemical conditions. We apply the developed SERS substrate for Raman measurements and mapping of HeLa cells and cell lysate. This method is used for identification of UV-induced damage and detection of nanomolar concentrations of methylated guanine spiked in cell lysate samples.

Placental transfer of SSRI and SNRI antidepressants and effects on the neonate.

INTRODUCTION: We investigated placental transfer and neurobehavioural effects in neonates exposed to citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine or sertraline (SSRI's), or to venlafaxine (an SNRI). METHODS: Women receiving antidepressants during pregnancy and their neonates were studied. Cord and maternal drug concentrations were measured at birth and in the neonates plasma on day 3. Neonates were also assessed using a range of neurobehavioral tests and compared to controls. RESULTS: Median cord/maternal distribution ratio was 0.7-0.86 (range) for SSRIs, 0.72 for the SNRI venlafaxine and 1.08 for the O-desmethyl metabolite. Neonatal abstinence scores were significantly higher (p<0.05) in exposed infants than controls on day 1. Brazelton scores for habituation, social-interactive, motor and autonomic clusters, and serotonin scores were significantly greater (p<0.05) in exposed infants. DISCUSSION: Transfer of SSRIs and SNRIs across the placenta was substantial. Neonates developed mild behavioral symptoms in the early perinatal period but these were self-limiting and similar for both SSRIs and the SNRI venlafaxine.

Pharmacokinetics of quetiapine in overdose and the effect of activated charcoal.

The aim of the study was to investigate the pharmacokinetics of quetiapine overdose and the effect of charcoal. The data set included 204 concentration-time points from 54 quetiapine overdose events (median dose 2,700 mg (300-24,000 mg)). Charcoal was administered 0.5-6 h after 19 overdoses. A fully Bayesian methodology for population pharmacokinetic analysis was used and data were modelled using WinBUGS. Uncertainty in the dose history was considered in model building by estimating dose amount and dose time within a possible range. Inclusion of informative priors stabilized the model and population parameter values could be estimated well. A one-compartment model with first-order input and first-order elimination described the data. The final model included uncertainty in dose time. The median and interquartile range of the half-life for individual patients was 6.6 h (4.9-8.4 h). Charcoal was estimated to reduce fraction absorbed by 35%. Co-ingested CYP3A4 inhibitors appeared to decrease clearance and CYP3A4 inducers increase clearance. Charcoal administration may be beneficial after quetiapine overdose.

Label-free cell-substrate adhesion imaging on plasmonic nanocup arrays.

Cell adhesion is a crucial biological and biomedical parameter defining cell differentiation, cell migration, cell survival, and state of disease. Because of its importance in cellular function, several tools have been developed in order to monitor cell adhesion in response to various biochemical and mechanical cues. However, there remains a need to monitor cell adhesion and cell-substrate separation with a method that allows real-time measurements on accessible equipment. In this article, we present a method to monitor cell-substrate separation at the single cell level using a plasmonic extraordinary optical transmission substrate, which has a high sensitivity to refractive index changes at the metal-dielectric interface. We show how refractive index changes can be detected using intensity peaks in color channel histograms from RGB images taken of the device surface with a brightfield microscope. This allows mapping of the nonuniform refractive index pattern of a single cell cultured on the plasmonic substrate and therefore high-throughput detection of cell-substrate adhesion with observations in real time.

Antidepressant toxicity and the need for identification and concentration monitoring in overdose.

Antidepressant drugs are among the most commonly encountered causes of self-poisoning. These drugs include tricyclics, tetracyclics, bicyclics and monocyclics, as well as monoamine oxidase (MAO) inhibitors and selective serotonin reuptake inhibitors (SSRIs). Of these, the tricyclic antidepressants (TCAs) are generally more toxic in overdose, with major toxicity usually manifesting within the first 6 hours after overdose. Various studies indicate that patients at risk of toxicity from TCA overdose may be identified by neurological, cardiovascular and electrocardiography status, together with a quantitative estimate of the plasma drug concentration. While there are various methods available for such chemical estimations, the most satisfactory appears to be fluorescence polarisation immunoassay which gives rapid quantitative results for a variety of TCAs. The selective MAO-A inhibitor antidepressants and the SSRIs are relatively nontoxic when taken alone. However, overdoses of combinations of MAO inhibitors and either SSRIs or TCAs with serotonin reuptake blocking activity may result in a serotonin syndrome with a severe or fatal outcome. Features of this syndrome include hyperpyrexia, disseminated intravascular coagulation, convulsions, coma and muscle rigidity, which may not develop until 6 to 12 hours after overdose. While quantitative chemical identification of these drugs following overdose is helpful in confirming the diagnosis, it is not mandatory. The increasing use of MAO-A inhibitors and SSRIs in the treatment of depression suggests that careful clinical observation is required when combination overdoses are suspected.

Application of a multi-faceted approach for the assessment of treatment response in falciparum malaria: a study from Malaysian Borneo.

Thirty-two patients reporting to the Lundu District Hospital, Sarawak, Malaysian Borneo, with uncomplicated falciparum malaria were recruited into a multifaceted study to assess treatment response. Following combined chloroquine and sulphadoxine/pyrimethamine treatment the patients were followed for 28 days according to the World Health Organisation in vivo drug response protocol. The in vivo study revealed that 13 (41%) of the patients had a sensitive response to treatment, five (16%) cleared asexual stage parasites but had persistent gametocytes, 11 (34%) had RI type resistance and three (9%) had RII type resistance requiring quinine intervention before day 7 for parasite clearance. Although clinically insignificant, patients with persistent gametocytes, surviving chloroquine and sulphadoxine/pyrimethamine treatment during maturation, were placed in the reduced response to treatment group for analysis. Allelic typing detected 100% prevalence of the pfcrt K76T marker associated with chloroquine resistance and 78% prevalence of the pfdhfr NRNL haplotype associated with sulphadoxine/pyrimethamine treatment failure. High serum chloroquine levels and pfdhfr haplotypes with

Gas-liquid chromatographic determination of ibuprofen in human plasma.

A gas-liquid chromatographic method for the estimation of Ibuprofen in human plasma is described. The procedure is rapid with the free drug being analysed thus eliminating the need for any derivatisation steps. The method allows the drug concentrations to be analysed down to a level of 2 mg/l using 2 ml plasma.

Determination of paracetamol in human serum.

A procedure is described that gives quantitative extraction of paracetamol from serum. This, together with derivatisation and gas chromatography, provides a simple method that facilitates the rapid estimation of the drug in serum in the range 5--500 mg/litre.

Cyclosporin immunosuppression of sheep: pharmacokinetics and allograft survival.

A chronically immunosuppressed sheep model was established using a regimen of cyclosporin A (CsA; 2-3mg/kg twice daily) and ketoconazole (10mg/kg twice daily). Blood CsA concentrations reached a steady-state after 17 days of treatment. The clearance of CsA decreased from a mean (95% CI) of 9.47 (6.2-12.7)ml/min/kg after a single (first) dose (3mg/kg i.v.) to 1.62 (1.38-1.86)ml/min/kg after 18 days of CsA (3mg/kg i.v. twice daily) co-administration with ketoconazole. These data indicated that the combination of CsA and ketoconazole could be used to give stable high concentrations of CsA in the sheep. Using this regimen in the sheep, the long-term survival of skin allografts was monitored as an indicator of effective immunosuppression. CsA in blood was measured daily and CsA dose adjusted to various target concentration ranges. Provided that the trough concentration of blood CsA was maintained between 1500-2500 mg/l, long-term healthy skin allografts were maintained on the sheep without significant adverse effects on haematological or biochemical parameters.

Simultaneous determination of lidocaine, mexiletine, disopyramide, and quinidine in plasma by high performance liquid chromatography.

A high performance liquid chromatographic method is described for the simultaneous quantitation of four commonly prescribed antiarrhythmic drugs: lidocaine, mexiletine, disopyramide, and quinidine. An isocratic system using a reverse phase column was used to separate these compounds. Coefficients of variation were less than 4%.

The analysis of several nonopiate narcotic analgesics and cocaine in serum using high-performance liquid chromatography.

This paper describes a procedure for the quantitative determination of methadone, meperidine, normeperidine, pentazocine, propoxyphene, norpropoxyphene, and dextromoramide in serum down to levels of 10 micrograms/L and of cocaine down to 25 micrograms/L. The procedure involves a simple extraction technique and high-performance liquid chromatography and is suitable for use in overdose drug screening, forensic toxicology, therapeutic drug monitoring, and pharmacokinetic studies.

Cardiovascular and neurological toxicity of venlafaxine.

1. We report a case of venlafaxine overdose and describe pharmacokinetic data on drug disposition. 2. Case report. Serial venlafaxine levels were measured and drug half-life calculated and compared to data at therapeutic concentrations. Metabolite concentrations were also measured and the potential for toxicity described with reference to individual variation in such metabolism 3. Venlafaxine can cause significant cardiac and neurotoxicity. Its potential for causing such toxicity may be dependent on whether an individual has the extensive metaboliser cytochrome CYP2D6 phenotype or the poor metaboliser phenotype

The use of buffered celite columns in drug extraction techniques and their proposed application in forensic toxicology.

The recoveries of acidic, basic, and neutral drugs through buffered celite columns are reported. The methods are rapid, simple, clean, and efficient, especially with compounds having a high volatility.

A comparison of the borate-celite column screening technique with other extraction methods in forensic toxicology.

The comparison of five different extraction techniques from postmortem tissues was reported. The borate/celite column chromatography technique generally gave the best yields and its use as a screening method in forensic toxicology was discussed.

Extraction procedures for some common drugs in clinical and forensic toxicology.

The results of four extraction systems for 86 drugs are reported. These systems were investigated with the view to obtaining a rapid, reliable, and efficient extraction technique in clinical and forensic toxicology.

The effect of decontamination procedures on the pharmacokinetics of venlafaxine in overdose.

The aim of this work was to investigate the pharmacokinetics (PK) of venlafaxine in overdose and the effects of single-dose activated charcoal (SDAC) and whole-bowel irrigation (WBI), alone or in combination, as methods of decontamination. The data included 339 concentration-time points from 76 venlafaxine overdose events (median dose 2,625 (150-13,500 mg)); 69 were slow-release doses. SDAC, WBI, a combination of both, or no decontamination were administered to patients as decided by the treating clinician. The data were modeled using WinBUGS (Windows Bayesian Inference Using Gibbs Sampling). A one-compartment model with first-order input and elimination provided an adequate description of the data. SDAC increased clearance (CL) of venlafaxine by 35%, and SDAC and WBI combined reduced the fraction absorbed by 29%. However, the latter produced a greater reduction in maximum plasma concentration (C(max)) for a similar drop in area under the plasma concentration-time curve (AUC). Both SDAC alone, and a combination of SDAC and WBI, decreased the AUC after venlafaxine overdose, but the combination may be more beneficial because it reduces peak concentrations to a greater extent.

Effect of open-chest surgery in the lateral position on blood propofol concentration during target-controlled infusion of propofol.

Our research hypothesis was that single lung ventilation during thoracic surgery in the lateral position increases the blood concentration of propofol during target-controlled infusion. Thirty adult patients in two tertiary referral hospitals undergoing open-chest surgery were studied. Anaesthesia was induced and maintained with propofol using a Diprifusor (Graseby 3500) computer-controlled pump set to deliver a blood concentration of 4 tg.ml(-1). Blood samples were taken with the patient positioned in (1) the supine position 20 minutes after induction (supine); (2) the lateral position just prior to one-lung ventilation (lateral); (3) the lateral position five minutes after commencing one-lung ventilation (OLV5) and (4) the lateral position 20 minutes after commencing one-lung ventilation (OLV20). Propofol concentrations were determined by high performance liquid chromatography. The target-controlled infusion target level was maintained at 4 microg.ml(-1) during the study period for all cases. The mean (SD) propofol blood concentration (microg.ml(-1)) at each stage was 5.5 (1.5) supine, 5.3 (1.1) lateral, 5.3 (1.2) OLV5 and 5.1 (1.2) OLV20. Repeated measures ANOVA showed an F value 1.9, lambda 5.5 and P value 0.15. Post hoc analysis did not identify a significant difference between the sample times. During target-controlled infusion of propofol, mean blood propofol concentrations did not change significantly from those obtained with the patient supine after up to 50 minutes in the lateral position during thoracic surgery, or 20 minutes after commencing one-lung ventilation.