Reduced Synchronization in the Visual Cortex of Cats with Strabismic Amblyopia

Synchronous firing of spatially separate neurons was studied with multi-electrode recordings in area 17 of the visual cortex of strabismic cats which had developed behaviourally verified amblyopia of the deviated eye. Responses of neurons were evoked with moving light bars or gratings of different spatial frequency. Neurons driven by the normal eye displayed stronger synchronization of their responses than neurons dominated by the amblyopic eye. These interocular differences were highly significant and particularly pronounced for grating stimuli of high spatial frequency. No interocular differences were noted with respect to the amplitudes of responses to the light bars and gratings. These results suggest reduced synchronization of population responses as a neurophysiological correlate of strabismic amblyopia and underline the importance of correlated firing of spatially separate cortical neurons for normal processing of visual information.     

Quality of life in GERD patients: Medical treatment versus antireflux surgery

Medical and surgical treatments are able to improve symptoms in patients with gastroesophageal reflux disease (GERD). The aim of this study was to evaluate the outcome in GERD patients without therapy, under continuous medical treatment, and after laparoscopic antireflux surgery. Five hundred seventy-nine consecutive patients underwent medical or surgical treatment for GERD-induced symptoms. Patients were studied in detail before and after treatment by means of a symptom questionnaire, endoscopy, esophageal manometry, 24-hour esophageal pH monitoring, and a barium esophagogram. In addition, quality of life was measured by the means of the Gastrointestinal Quality of Life Index (GIQLI) and the Health-Related Quality of Life (HRQL) questionnaire. Surgery was indicated and performed in 351 patients with persistent or recurrent GERD symptoms and/or complications, and in patients preferring surgery to medical treatment, despite the use of an adequate medication. The remaining 228 patients were treated with proton pump inhibitors (PPI) in the standard dose, or if required, the double dose. The outcome was assessed 3 and 12 months after treatment. While symptoms and quality of life were highly impaired in GERD patients without therapy compared with normal people, a significant improvement was obtained by PPI therapy. Following surgery, quality of life was normalized in all subsections and was significantly higher compared with the medically treated group. These results stayed constant in short-term and intermediate follow-up. Medical and surgical therapies are both able to improve symptoms and quality of life in GERD patients. Nevertheless, the outcome is significantly better following surgery. It can be suggested that surgical treatment may be the more successful therapy in the long-term. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–19, 2005 (poster presentation).     

Hemagglutination assay for human serum fibronectin

A hemagglutination assay for human serum fibronectin (Fn) is described. The assay is based on the capacity of Fn to bind to gelatin. Purified and human serum Fn agglutinate chromic chloride treated sheep red cells coated with gelatin in a quantitative and reproducible manner. The lowest Fn concentration giving positive hemagglutination was found to be 7 micrograms/ml, a sensitivity making it suitable for measurement of Fn in both normal and pathologic sera. The assay is simple and rapid and does not require specialized equipment.     

Temporal instability in the perception of strabismic amblyopia

Amblyopia is a developmental disorder of spatial vision resulting from an abnormal visual stimulation in early childhood. The aim of our study was to investigate the spatial and temporal distortions that occur in strabismic and anisometropic amblyopic vision. The main focus was on the temporal instability of amblyopic perception of low and high spatial frequencies. Our results indicate that temporal instability is perceived mainly by strabismic and strabismic-anisometropic amblyopes and occurs only at high spatial frequencies. We found two categories of temporal distortions in high spatial frequency patterns: a) the whole pattern is perceived as jittering, b) single lines or parts in a pattern are perceived as moving. Our data suggest that strabismus, in addition to amblyopia, is needed to elicit significant temporal distortions.     

Risks and difficulties in the treatment of malignant tumors of the lower face

The extensive malignant tumors of the face impose numerous problems regarding the surgical treatment due to, on one hand to their extension and on the other hand, to the aggressivity of the histological entity. The histopathology and the grading of these tumors are very helpful in orientating the specialist to choose the best therapeutic protocol in each case.     

Nanoencapsulation of a crystalline drug

The aim of this work was to assess the influence of various formulation parameters on the incorporation of a poorly water-soluble crystalline drug into nanoparticles. For this purpose, the influence of the polymer (polylactic acid, polysebacic acid terminated with lithocholic acid, and polysebacic acid-co-lithocholic acid) as well as the effect of the dispersion medium (aqueous phases at different temperatures, saline medium and ethanol) on the encapsulation was investigated. 3H-labelled drug was used in order to determine the loading efficiency by liquid scintillation counting. The solubility of the drug in the various polymer materials was assessed by differential scanning calorimetry (DSC). The solubility of the drug in the different dispersion media was then determined by gas chromatographic-mass spectrometric measurements. The highest loading ratios were obtained using poly (lactic acid) (PLA). However, the drug solubility in the polymers, determined by DSC analysis, cannot be considered as predictive for encapsulation efficiency. The study of the influence of the liquid outer phase showed that the encapsulation efficiency increased when the drug solubility in the dispersion medium (before acetone evaporation) decreased. These experiments made it possible to propose a mechanism to account for the leakage of the crystalline drug during the nanoprecipitation process. So, when acetone is eliminated by evaporation, the drug solubility in the dispersion medium decreases, leading to the formation of crystals. During nanoparticles storage, the crystals continue to grow, the nanoparticles serving as drug reservoirs. These findings highlight the importance of using a polymer with a specific affinity for the drug, and a dispersion medium with the lowest drug solubility to achieve an efficient encapsulation of a crystalline drug.     

Air bubbles pass the security system of the dialysis device without alarming

During hemodialysis microembolic findings have been noted after the venous chamber (subclavian vein). The aim of this study was to evaluate if air could pass the venous chamber and, if so, if it passes the safety-system detector for air-infusion without triggering an alarm.Various in vitro dialysis settings were performed using regular dialysis devices. A dextran fluid was used instead of blood to avoid the risk of development of emboli. Optical visualization as well as recirculation and collection of eventual air into an intermediate bag were investigated. In addition, a specifically designed ultrasound monitor was placed after the venous air trap to measure the presence of eventual microbubbles. Speed of dialysis fluid was changed, as was the level of the fluid in the air trap. Thereby a fluid level was considered "high" if it was close to the top of the air trap and "low" if it was around the mid part of the air trap. By optical vision microbubbles were seen at the bottom of the air trap and could pass the air trap towards the venous line without alarming. During recirculation several mL of air were collected in an intermediate bag after the venous line. Ultrasound monitoring exhibited the presence of microbubbles of the size of approximately 5 microm upwards passing to the venous line in all runs performed. Amount of bubbles differed between devices and in general an increased fluid speed correlated significantly with the increased counts of microbubbles/min. No alarming of the detector occurred. A more concentrated fluid allowed higher counts/min when flow was increased to 600 mL/min. Data revealed that air passes the safety-sensor in the air trap without alarming. The presence of air increased in general with fluid speed and a lower fluid level in the air trap. Differences were present between devices. If this affects the patients has to be elucidated.     

DNA vaccination and gene therapy: optimization and delivery for cancer therapy

This review will focus on DNA vaccine approaches for the prevention or treatment of cancer and its complications. DNA vaccine therapies are a relatively novel method of cancer treatment with the goal to induce immunity against tumor-associated antigens. Both viral and nonviral vaccines have been tested in preclinical and clinical models with variable success. However, the development of new delivery methods, such as electroporation, as well as the use of agents that improve antigen uptake or presentation, and the optimization of the transgene sequences, are overcoming historical drawbacks. Efficacy and safety issues of the in vivo use of DNA-based vaccines, as well as data from preclinical and recent clinical studies, are discussed. Novel developments will improve clinical efficacy, with the potential for DNA vaccination to enter in to the arsenal of cancer therapies in the near future.