Optical Fluorescence and Its Application to an Intravascular Blood Gas Monitoring System

Optical fluorescence has an extensive history of application in the laboratory to the measurement of ionic concentrations and the partial pressures of oxygen and carbon dioxide. The use of optical fluorescence based sensors to fulfill a recognized need for continuous invasive monitoring of arterial blood gases offers a number of inherent advantages. However, the requirements placed upon a blood gas probe and supporting instrumentation appropriate for use in the clinical environment result in significant design challenges in selection of suitable fluorescent dyes, maintenance of mechanical integrity while obtaining required miniaturization of sensors, and in the transmission, acquisition, and processing of low level light signals. An optical fluorescence based intravascular blood gas monitoring system has been developed which is particularly suited for the critical care and surgical settings and which has a sensor probe that can be introduced into the patient via a radial artery catheter. This system has shown an excellent agreement of measured with true values of pH, pCO2, and P02 in both in vitro and animal studies. Linear regression analysis of typical in vitro data, where true levels were established via tonometry and standardization to a high accuracy laboratory pH measuring instrument, shows slope/intercept values very close to 1.0/0.0 and correlation coefficients of greater than 0.99 for all three parameters.     

Somatosensory evoked potentials in adrenomyeloneuropathy

Adrenomyeloneuropathy (AMN) is an X-linked metabolic disorder causing accumulation of very-long-chain fatty acids with multifocal nervous system demyelination of the peripheral nerves, spinal cord, and cerebrum. The extent to which the disorder affects upper versus lower limbs or peripheral versus CNS has not been electrophysiologically defined in a large population nor differentiated in men and women. To determine patterns of nervous system demyelination and define gender differences, we studied 83 AMN patients with short latency median and posterior tibial nerve somatosensory evoked potentials (SSEPs). Most women (10/16) had abnormal median SSEPs all involving central pathways, whereas most men (59/67) had abnormal median SSEPs involving both peripheral and central pathways. Tibial SSEPs were abnormal in both sexes (14/15 women, 67/67 men), with either peripheral or central pathway involvement. This study demonstrates the frequent widespread involvement of both peripheral nerve and central somatosensory pathways in men with AMN and the predominantly central involvement in women.     

C?N Coupling of Indoles and Carbazoles with Aromatic Chlorides Catalyzed by a Single‐Component NHC‐Nickel(0) Precursor

A new and efficient nickel‐based protocol for the N‐arylation of indoles and carbazoles with aromatic chlorides, the least expensive of the aryl halides, is described. The procedure provides selectively N‐(hetero)arylation products in good to high yields, in short reaction times and without adding an excess of ligands.

     

From the viewpoint of a client

Collaboration between choreographers and architects still usually takes the traditional form of the latter designing sets for the former, while research on the relationship between architecture and dance is scant. One of the few examples of a choreographer working with then-current architectural concerns is William Forsythe and the Ballett Frankfurt in the late 1980s, particularly in Enemy in the Figure (1989) and Limb's Theorem (1990). These pieces show a profound understanding of and engagement with architectural issues then being addressed by Daniel Libeskind. Forsythe's interest in Libeskind was not his ‘deconstruction’, as has often been asserted, but in his operations on drawing. Their coincidence of intellectual interests and resulting friendship allows us to see clearly how concerns in architecture were also explored through the medium of ballet. It is a reminder too of a period, postmodernism, when architecture led theoretical discussions.     

Phage Display-based Strategies for Cloning and Optimization of Monoclonal Antibodies Directed against Human Pathogens

In the last two decades, several phage display-selected monoclonal antibodies (mAbs) have been described in the literature and a few of them have managed to reach the clinics. Among these, the anti-respiratory syncytial virus (RSV) Palivizumab, a phage-display optimized mAb, is the only marketed mAb directed against microbial pathogens. Palivizumab is a clear example of the importance of choosing the most appropriate strategy when selecting or optimizing an anti-infectious mAb. From this perspective, the extreme versatility of phage-display technology makes it a useful tool when setting up different strategies for the selection of mAbs directed against human pathogens, especially when their possible clinical use is considered. In this paper, we review the principal phage display strategies used to select anti-infectious mAbs, with particular attention focused on those used against hypervariable pathogens, such as HCV and influenza viruses.     

The Hedgehog-GLI Pathway Regulates MEK5-ERK5 Expression and Activation in Melanoma Cells

Malignant melanoma is the deadliest skin cancer, with a poor prognosis in advanced stages. We recently showed that the extracellular signal-regulated kinase 5 (ERK5), encoded by the MAPK7 gene, plays a pivotal role in melanoma by regulating cell functions necessary for tumour development, such as proliferation. Hedgehog-GLI signalling is constitutively active in melanoma and is required for proliferation. However, no data are available in literature about a possible interplay between Hedgehog-GLI and ERK5 pathways. Here, we show that hyperactivation of the Hedgehog-GLI pathway by genetic inhibition of the negative regulator Patched 1 increases the amount of ERK5 mRNA and protein. Chromatin immunoprecipitation showed that GLI1, the major downstream effector of Hedgehog-GLI signalling, binds to a functional non-canonical GLI consensus sequence at the MAPK7 promoter. Furthermore, we found that ERK5 is required for Hedgehog-GLI-dependent melanoma cell proliferation, and that the combination of GLI and ERK5 inhibitors is more effective than single treatments in reducing cell viability and colony formation ability in melanoma cells. Together, these findings led to the identification of a novel Hedgehog-GLI-ERK5 axis that regulates melanoma cell growth, and shed light on new functions of ERK5, paving the way for new therapeutic options in melanoma and other neoplasms with active Hedgehog-GLI and ERK5 pathways.     

A fluorescent chemosensor for sodium based on photoinduced electron transfer

A new optical sensor suitable for practical measurement of sodium in serum and whole blood samples is described. The optical sensor is based on a novel PET (photoinduced electron transfer) fluoroionophore immobilized in a hydrophilic polymer layer. The design concept of the fluoroionophore follows the receptor-spacer-fluorophore approach to sensor design using intramolecular PET-based signal transduction. Key to the development of this sensor is the identification of a nitrogen-containing, sodium-binding ionophore, coupled with a fluorophore having the correct spectral and electron-accepting properties. The slope of the sensor is approximately 0.5%/mM in the typical clinically significant range of 120-160 mM. This sensor has been implemented into a disposable cartridge, used for a commercially available critical care analyzer (Roche OPTI CCA) with precision better than +/- 1 mM (1 SD). The sensor displays excellent stability against hydrolysis and oxidation, leading to slope changes <5% after 9 months wet storage at 30 degrees C. On the basis of this design concept, fluoroionophores for other cations such as potassium, calcium and magnesium can be prepared by substitution of the ionophore.