Variations of homovanillic acid levels in ventricular cerebrospinal fluid

We studied the nycterohemeral variations of homovanillic acid (HVA) in ventricular cerebrospinal fluid (CSF) in 24 patients undergoing monitoring of intracranial pressure as part of the normotensive hydrocephalus (NTH) work-up. CSF samples were obtained every 4 h in each patient. The mean individual values of HVA in the ventricular CSF ranged from 133 to 421 ng/ml, and they could not be correlated to any clinical feature. The intraindividual levels of HVA were stable throughout 24 hours, with a variation coefficient inferior to 10% in 63% of cases, and inferior to 20% in all the patients.     

Reduced pathogenicity associated with a small plaque variant of the Egyptian strain of Rift Valley fever virus (ZH501)

Variants of Rift Valley fever virus producing plaques in CER cells of four different sizes are described. A plaqueforming unit (PFU) variant forming minute plaques was isolated and purified. Virus derived from this variant was not pathogenic to adult Swiss albino mice by the intraperitoneal (i.p.) route and was less pathogenic than the parent strain (ZH501) to adult Sprague Dawley rats by i.p. route, but produced typical severe liver necrosis in adult Syrian hamsters with intranuclear and intracytoplasmic eosinophilic inclusions. Antigen and antiserum to the minute variant prepared in mice reciprocally cross-reacted with antisera and antigens of the original strain (ZH501) in the complement fixation test. Plaque size of the minute variant remained constant after serial passages in cell culture and in suckling mouse brain. When the minute plaque variant was passaged i.p. in hamsters, virus which formed large plaques in CER cells was recovered from the hamster sera.     

Kinetic investigation of photopolymerizations induced by laser beams

Real time infrared (RTIR) spectroscopy was used to study the kinetics of the polymerization of acrylic monomers exposed to the 337,4 nm continuous emission of a Kr⁺ laser. Conversion versus time curves were directly recorded in the millisecond timescale, thus allowing a precise evaluation of the polymerization rate and of the induction period due to O₂ inhibition. The influence of the type and concentration of photoinitiator and of the laser beam intensity on the polymerization profile was examined for a 20 μm thick polyurethane-acrylate (Actilane 20) coating. The growth of the radical concentration and its dependence on the initiation rate was determined from the kinetics of the dark polymerization which develops just after the laser exposure. Pulsed laser irradiation proved to be very effective in initiating the polymerization, the overall quantum yield reaching values up to 2500 mol · photon^?1.     

Lithotripsy for calculi in caliceal diverticula?

There is continuing debate about the optimum management of patients with calculi in caliceal diverticula. Extracorporeal piezoelectric lithotripsy (EPL) has the advantage of being non-invasive, whereas endourological management can treat the underlying anatomical problem. A total of 20 patients with calculi in caliceal diverticula were treated with EPL. Twelve of 16 patients with symptoms (75%) were rendered symptom-free but only 5 (25%) became stone-free. This information should be of value in counselling patients before selecting the appropriate treatment.     

Effects of simvastatin, pentoxifylline and spironolactone on hepatic fibrosis and portal hypertension in rats with bile duct ligation

Aims/Methods: Our aim was to the antifibrotic and hemodynamic effects of simvastatin (SMV), pentoxifylline (PTX) and spironolactone (SPN), three drugs which may have antifibrotic and/or portal hypotensive properties, in a model of hepatic fibrosis and portal hypertension induced in rats by bile duct ligation. A blind study was performed in five groups of 53 Sprague-Dawley rats: sham, placebo (PL), SMV (2.5 mg·kg⁻¹·J⁻¹, PTX (50 mg·kg⁻¹·J⁻¹) and SPN (100 mg·kg⁻¹·J⁻¹). Drugs were administered by daily gavage over a 4-week period as soon as bile duct ligation was performed. At day 28, the following parameters were evaluated: area of hepatic fibrosis by image analysis after staining collagen with picrosirius and plasma concentrations of hyaluronate, splanchnic and systemic hemodynamics (radiolabeled microspheres).Results: Portal venous pressure (PL: 15.5±1.5, SMV: 15.8±2.5, PTX: 15.9±1.8, SPN: 13.5±2.1 mmHg, p<0.05) and porto-systemic shunts (PL: 30±31, SMV: 18±27, PTX: 25±24, SPN: 5±4%, p<0.05) were significantly reduced in the SPN group; other hemodynamic parameters were not significantly altered. There was a significant correlation between porto-systemic shunts and portal pressure (r_s=0.47, p<0.01). The area of fibrosis was not significantly different among the four groups of bile duct ligated rats (PL: 8.7±3.9, SMV: 7.1±3.6, PTX: 7.8±2.7, SPN: 6.6±3.3%) but was higher than in sham rats (1.5±0.5%, p<0.001). Hyaluronate was significantly higher in bile duct ligated rats (from 374±162 to 420±131 μg/l, among the four groups) than in sham rats (52±16 μg/l, p<0.0001).Conclusions: In this model, none of the drugs prevented hepatic fibrosis. On the other hand, spironolactone decreased portal pressure and prevented porto-systemic shunts. Therefore, this drug may have beneficial effect in patients with early portal hypertension.