Magnetic resonance spectroscopy findings in a case of hyperglycaemic hemianopia.

INTRODUCTION: Patients with nonketotic hyperglycaemia may present with neurological manifestations, including hemianopia. Thus far, the pathophysiology of such neurological events remains unknown, although the findings on magnetic resonance imaging (MRI) may help to elucidate the underlying mechanisms. CASE REPORT: This report describes a patient who had an episode of homonymous hemianopia, which coincided with a state of nonketotic hyperglycaemia. Initial MRI showed hypointense areas on T2-weighted and FLAIR sequences, involving the internal portion of the right occipital cortex and adjacent white matter, with mild hyperintensity on diffusion-weighted imaging. Magnetic resonance spectroscopy revealed significant increases in cerebral metabolites. Dramatic clinical and neuroimaging improvements were progressively observed over 3 weeks, following rehydration and normalization of blood glucose levels with insulin therapy. CONCLUSION: In this patient, magnetic resonance spectroscopy was used in combination with other neuroimaging methods and clinical evidence to suggest that hyperosmolality leading to intracellular dehydration in localized brain regions should be considered a potential underlying mechanism responsible for reversible neurological symptoms in nonketotic hyperglycaemia.

[Diagnosis and treatment of tearing in infancy]. / Larmoiement du nourrisson : conduite à tenir et thérapeutique.

Tearing in infancy is a very frequent symptom, particularly during the first year of life. A definite diagnosis can be made easily, only by questioning the parents about the characteristics and the evolution of the tearing since the birth and with a simple examination. The main causes are congenital nasolacrimal duct obstruction account of his high frequency in infant and congenital glaucoma account of his seriousness.

[Usefulness of voriconazole in treatment of Phoma glomerata after penetrating injury]. / Endophtalmie à Phoma glomerata après plaie du globe et efficacité du traitement par voriconazole en intravitréen.

We report the first case of endophthalmitis caused by Phoma glomerata. A 32-year-old man who underwent retinal detachment surgery consecutive to a penetrating globe injury presented with endophthalmitis 7 days after surgery. Anterior chamber tap and intravitreal injection of antibiotics (ceftazidime and vancomycin) were performed systematically. Fungus was observed at microscopic examination of the aqueous humor and treatment with intravitreal injection of amphotericin B was decided. The patient failed to improve with intravitreal amphotericin B but responded clinically to intravitreal voriconazole. The fungus was identified after culture as Phoma glomerata. The MIC for amphotericin B was 1microg/ml, for caspofungin was 2microg/ml, and for itraconazole was 8microg/ml or more. The MIC for voriconazole was up to 8microg/ml. The clinical response after intravitreal injection may be related to the high concentrations reached in the vitreous. Because of severity and ominous prognosis of intraocular fungal infections and posttraumatic Phoma ocular infections, aggressive management is required by intravitreal voriconazole administration.

Study of optimal separation of two circular phased-array coils via an equivalent circuit.

The coil separation of phased-array coils is an important issue if a wide area of interest is to be imaged. An equivalent circuit of two circular-shaped coils was used to compute the optimal distance in a two phased-array coil. This circuit included the mutual inductance of two circular coils. An expression for the mutual inductance was derived and the resulting values included in the circuit. With all these elements an equivalent circuit of two overlapped circular coils was built to simulate a phased-array coil. To find a solution to this circuit, specifically written programmes in Spice Opus Light were used. Optimal separations were calculated from separation-vs-attenuation for different coil radii. Results compare very well with those reported in the literature.

A Comparative Study on the Adsorption of Triton X-100 and Tween 20 onto Latexes with Different Interfacial Properties

In this paper we have studied the adsorption of two nonionic surfactants, Triton X-100 and Tween 20 (polyoxyethylene (20) sorbitan monolaurate) onto latexes with different interfacial properties. Four different samples of polystyrene beads were used in this study. A hydrophobic sample was prepared by conventional emulsion polymerization of styrene. Hydrophilic polymer colloids were prepared by the emulsifier-free emulsion copolymerization of styrene and 2-hydroxyethylmethacrylate in different proportions and acrylic acid. In all cases potassium persulfate was used as initiator. In order to consider the mechanism of the adsorption at the different liquid-solid interfaces, adsorption isotherms under different pH and ionic strength conditions were performed. Electrokinetic characterization and colloidal stability of bare hydrophobic and hydrophilic latexes and the surfactant-latex complexes were compared to understand the effect of the nonionic surfactant on the electric double layer structure. The results showed that Tween 20 and Triton X-100 are adsorbed in the same way on surfaces with different polarity but in different amounts. Hydrophobic interaction is the main driving force in the adsorption. The effect of the adsorption on the electrokinetic properties and stability of the latexes was found to be different for hydrophobic and hydrophilic latexes as a consequence of the dissimilar interfacial properties of these two latex samples.

Colloidal Stability of Polymer Colloids with Different Interfacial Properties: Mechanisms

An investigation is presented into the effects of interfacial properties on the colloidal stability of monodisperse polymer colloids using a sulfonate polystyrene (PS) and a styrene-hydroxyethyl methacrylate copolymer (PSHEMA) latex. Both latexes were prepared by emulsion copolymerization in the absence of surfactant. The experimental stability of these colloidal dispersions was studied in relation to the concentration (Ce) of an indifferent electrolyte. Results are compared to current models, relating the stability ratio (W) to intermolecular forces between particles. The Hamaker constant (A) obtained from the log W-log Ce plots and using the DLVO theory is much lower than the theoretical value given by the Lifshitz theory. To achieve good agreement between the experimental and theoretical A values, different corrections to the DLVO theory were introduced. First, the modified stability factor (W) was numerically estimated taking into account the hydrodynamic effect as given by L. A. Spielman [J. Colloid Interface Sci. 33, 562 (1970)]. Next, the real size of the hydrated ions was also considered. With these modifications only, small discrepancies remained between the theoretical and experimental values of the Hamaker constant in the case of the PS latex; however, the A value obtained for the PSHEMA latex studied is rather low. As HEMA is a nonionic and polar monomer, a new correction was made to the DLVO theory: the effect of electrosteric stabilization. Both steric repulsion and the electrostatic effect are shown to play a significant role in maintaining dispersion stability for the PSHEMA latex.

Neural networks and fuzzy logic in clinical laboratory computing with application to integrated monitoring.

We present an analysis of the computational features of neural networks and fuzzy logic architectures which attempts to explain their recent popularity as well as their drawbacks. Based upon many reports in several fields, we identify the key computational requirements in the clinical laboratory setting, and review several classical tools. In particular we make the observation that all of these needs may be viewed as a search for an appropriate mathematical mapping. We suggest that the neural networks promise as a universal function approximant is the main source of its apparent attractivity. We then describe a customized neural network architecture as a non-linear, adaptive signal processor for integrated monitoring. This architecture is employed in the Adaptive Real-Time Anesthesiologist Associate (ARTAA) system, which has been developed as a joint project at the Department of Anesthesiology, Albert Einstein Medical Center and the Electrical and Computer Engineering Department, Drexel University in Philadelphia, USA. In this application the neural network realizes a non-linear scalar map from the set of physiological signals to a vital function status (VFS) indicator. The system is now under clinical testing.

Sleep apnea syndromes (SAS) of specific etiology: review and incidence from a sleep laboratory.

Sleep apnea syndrome (SAS) results from modification in the control of respiration and of upper airway caliber during sleep. Although there is some overlap between central (CSAS) and obstructive (OSAS) sleep apnea syndromes, each syndrome has specific pathological associations. The first part of this review concerns the pathophysiology of OSAS, including periodic breathing and upper airway collapse. In the second part, each specific etiology is examined, and the respective contribution of anatomic narrowing and neuromuscular dysfunction of the upper airway is mentioned. Our experience with about 375 patients with sleep-related breathing disorders is also reported, with regard to the specific etiologies of CSAS and OSAS.

Graded-index surface or buried waveguides by ion exchange in glass.

Graded-index surface or buried waveguides have been realized by thermal or electrically induced ionic exchange in glass. Deep waveguides can be obtained up to 200 microm when Li(+) ions are used. Using Ag(+) ions, buried waveguides can be obtained with a maximum index at 80 microm into the substrate. Typical losses for these devices are 0.5 dB/cm. Maximum index variations can be tuned from 0 to 0.11.