Influence of solution viscosity and injection protocol on distribution patterns of jet injectors: Application to photodynamic tumour targeting

Photodynamic therapy of deep or nodular skin tumours is currently limited by the poor tissue penetration of the porphyrin precursor 5-aminolevulinic acid (ALA) and preformed photosensitisers. In this study, we investigated the potential of jet injection to deliver both ALA and a preformed photosensitiser (meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate, TMP) into a defined volume of skin. Initial studies using a model hydrogel showed that as standoff distance is increased, injection depth decreases. As the ejected volume is increased, injection depth increases. It was also shown, for the first time, that, as injection solution viscosity was increased, for a given injection setting and standoff distance, both total depth of jet penetration, L-t, and depth at which the maximum width of the penetration pattern occurred, L-m, decreased progressively. For a standoff distance of zero, the maximum width of the penetration pattern, L-w, increased progressively with increasing viscosity at each of the injection settings. Conversely, when the standoff distance was 2.5 mm, L-w decreased progressively with increasing viscosity. Studies with neonate porcine skin revealed that an injection protocol comprising an 8.98 mPas solution, an arbitrary injection setting of 8 and a standoff distance of zero was capable of delivering photosensitisers to a volume of tissue (L-t of 2.91 mm, L-m of 2.14 mm, L-w of 5. 10 mm) comparable to that occupied by a typical nodular basal cell carcinoma. Both ALA and TMP were successfully delivered using jet injection, with peak tissue concentrations (67.3 mg cm(-3) and 5.6 mg cm(-3), respectively) achieved at a depth of around 1.0 mm and substantial reductions in drug concentration seen at depths below 3.0 mm. Consequently, jet injection may be suitable for selective targeting of ALA or preformed photosensitisers to skin tumours. (c) 2007 Elsevier B.V. All rights reserved.

Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma

Background: We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods.
Methods: A nonbronchoscopic bronchoalveolar lavage (BAL) procedure was performed on children presenting for an elective surgical procedure. Eosinophil-derived (eosinophil cationic protein, ECP) and mast cell-derived (histamine/tryptase) mediator concentrations were measured in the BAL fluid. A detailed history and serum immunoglobulin E were used to classify the children into four groups: atopic with and without asthma, viral-associated wheeze and normal controls.
Results: The ECP concentrations in BAL from atopic asthmatic subjects were significantly higher than those measured in BAL from normal controls (P < 0.01), no other groups differed significantly. Histamine concentrations were elevated in both the atopic asthmatic and viral-associated wheeze groups compared with controls (P < 0.02) and additionally higher concentrations were obtained in atopics with asthma compared with atopics without asthma (P < 0.03). Tryptase concentrations did not differ between groups, although the tryptase and histamine concentrations correlated significantly (r = 0.78, P < 0.0001).
Conclusions: Elevated histamine concentrations were found in children with wheeze regardless of the aetiology, whereas ECP was only elevated in those asthmatics with atopy. This suggests that even in relatively quiescent periods, there is some on going activation of airway eosinophils in children with atopic asthma.

Development and validation of a dried blood spot-LC-APCI-MS assay for estimation of canrenone in paediatric samples

A selective and sensitive liquid chromatography (LC)-atmospheric pressure chemical ionisation (APCI)-mass spectroscopic (MS) assay of canrenone has been developed and validated employing Dried Blood Spots (DBS) as the sample collection medium. DBS samples were prepared by applying 30 mu l of spiked whole blood onto Guthrie cards. A 6 mm disc was punched from the each DBS and extracted with 2 ml of methanolic solution of 17 alpha-methyltestosterone (Internal Standard). The methanolic extract was evaporated to dryness and reconstituted in acetonitrile:water (1:9, v/v). The reconstituted solution was further subjected to solid phase extraction using HLB cartridges. Chromatographic separation was achieved using Waters Sunfire C18 reversed-phase column using isocratic elution, followed by a high organic wash to clear late eluting/highly retained components. The mobile phase consisted of methanol:water (60:40, v/v) pumped at a flow rate of 0.3 ml/min. LC-APCI-MS detection was performed in the selected-ion monitoring (SIM) mode using target ions at m/z 341.1 and 303.3 for canrenone and internal standard respectively. The selectivity of the method was established by analysing DBS samples from 6 different sources (individuals). The calibration curve for canrenone was found to be linear over 25-1000 ng/ml (r >0.994). Accuracy (% RE) and precision (% CV) values for within and between day were

Radiocarbon dating of bulk peat samples from raised bogs: nonexistence of a previously reported 'reservoir effect'?

In 1995. an unexpected reservoir effect was reported in sequences of bulk C-14 dates of raised bog peat. In most peat Studies bulk C-14 dates are used for obtaining chronologies. Therefore it is important to confirm and quantify such a C-14 reservoir effect. Five bulk peat samples from the raised bog Engbertsdijksveen were conventionally C-14 dated. The same core had previously been precisely dated by C-14 AMS dates of carefully selected above-ground plant remains. The existence of a reservoir effect in bulk peat C-14 samples could not be confirmed. Other explanations for the reported reservoir effect are discussed. (C) 2004 Elsevier Ltd. All rights reserved.

Detection of glucocorticoid bioactivity in bovine urine samples using a reporter gene assay.

The illegal use of anabolic substances in the meat producing industry is an ongoing problem due to the continual production of new synthetic compounds and/or the practice of low-level cocktail administration to avoid detection by the surveillance schemes of EU member states National Plan surveillance systems.

We present a highly sensitive reporter gene assay and sample extraction procedure based on a two step solid phase extraction and high performance liquid chromatography, developed for the detection of glucocorticoid abuse in bovine urine. The assay is capable of detecting compounds with glucocorticoid bioactivity and is extremely sensitive with an EC50 of 0.79 ng mL-1 for dexamethasone. New or unknown compounds with glucocorticoid bioactivity and low-level cocktail mixtures are detectable by this assay.

Cross-reactivity data for a range of 11ß-hydroxyglucocorticoids has been provided. This assay shows low interference from the 11-keto prohormones and other steroidal hormones. The assay may be suitable for application in other matrices such as hair. In conclusion this screening assay offers advantages over existing analytical techniques.

A preliminary investigation into the use of testate amoebae for the discrimination of forensic soil samples

We present the results of an initial investigation into the efficacy of using testate amoebae for the discrimination of soils from wet ground and puddles, as little attention has been given to these organisms in forensic science. The preservation of testate amoebae in these sediments is generally good, although test concentrations are low. Statistical analysis suggests that restate amoebae assemblages are somewhat spatially distinct and have potential to be used for soil discrimination. A case study is presented where mineralogical (X-ray diffraction) and restate amoebae analyses are used in conjunction to clarify the scene of crime in a 'cold case' murder enquiry. Testate amoebae were recovered from dried sediment residues on clothing 10 years after the murder. Despite these promising results, further experimental work is crucial to examine the spatial and temporal variation of amoebae assemblages in water films, wet ground and puddles before they can be added to the armoury of methods available to the forensic biologist.

Development of ELISAs for detecting domoic acid, okadaic acid, and saxitoxin and their applicability for the detection of marine toxins in samples collected in Belgium

Okadaic acid, a diarrhetic shellfish poison, domoic acid, an amnesic shellfish poison, and saxitoxin, a paralytic shellfish poison, are three of the best-known marine biotoxins. The mouse bioassay is the method most widely used to detect many of these toxins in shellfish samples, but animal welfare concerns have prompted researchers to seek alternative methods of detection. In this study, three direct competitive enzyme-linked immunosorbent assays (ELISAs), each based on antibodies raised in rabbits against a conjugate of the analyte of interest, were developed for marine biotoxin detection in mussel, oyster, and scallop. One assay was for okadaic acid, one for saxitoxin, and one for domoic acid usually detected and quantified by high-performance liquid chromatography-ultraviolet light (HPLC-UV). All three compounds and a number of related toxins were extracted quickly and simply from the shellfish matrices with a 9 : 1 mixture of ethanol and water before analysis. The detection capabilities (CC values) of the developed ELISAs were 150 mu g kg-1 for okadaic acid, 50 mu g kg-1 for domoic acid, and 5 mu g kg-1 or less for saxitoxin. The assays proved satisfactory when used over a 4-month period for the analysis of 110 real samples collected in Belgium.

Development of a recombinant Fab-fragment based electrochemical immunosensor for deoxynivalenol detection in food samples

A reliable and cost-effective electrochemical method for the detection of deoxynivalenol (DON) in cereals and cereal-based food samples based on the use of a novel anti-DON Fab fragment is presented. The analytical system employed, Enzyme-Linked-Immunomagnetic-Electrochemical (ELIME) assay, is based on the use of immunomagnetic beads (IMBs) coupled with eight magnetized screen-printed electrodes (8-mScPEs) as electrochemical transducers.

Effective monitoring for ractopamine residues in samples of animal origin by SPR biosensor and mass spectrometry

Ractopamine (RCT) is a member of the beta-2-agonist (beta-agonist) family. It is licensed for use as an animal growth promoter in more than 20 countries worldwide, including the United States and Canada, but is either not licensed or prohibited by over 150 others, including those within the European Union. The issue of the use of RCT in livestock bound for human consumption has risen to prominence recently following the decision by The People's Republic of China to ban the import of pork from a number of processing plants after finding traces of RCT in shipments from the U.S.A.