Multidimensional scaling of emotional responses to music in patients with temporal lobe resection.

The present study investigated emotional responses to music by using multidimensional scaling (MDS) analysis in patients with right or left medial temporal lobe (MTL) lesions and matched normal controls (NC). Participants were required to evaluate emotional dissimilarities of nine musical excerpts that were selected to express graduated changes along the valence and arousal dimensions. For this purpose, they rated dissimilarity between pairs of stimuli on an eight-point scale and the resulting matrices were submitted to an MDS analysis. The results showed that patients did not differ from NC participants in evaluating emotional feelings induced by the musical excerpts, suggesting that all participants were able to distinguish refined emotions. We concluded that the ability to detect and use emotional valence and arousal when making dissimilarity judgments was not strongly impaired by a right or left MTL lesion. This finding has important clinical implications and is discussed in light of current neuropsychological studies on emotion. It suggests that emotional responses to music can be at least partially preserved at a non-verbal level in patients with unilateral temporal lobe damage including the amygdala.

Antidepressants for patients with tinnitus.

BACKGROUND: Tinnitus is described as the perception of sound or noise in the absence of real acoustic stimulation. It has been compared with chronic pain, and may be associated with depression or depressive symptoms which can affect quality of life and the ability to work. Antidepressant drugs have been used to treat tinnitus in patients with and without depressive symptoms. OBJECTIVES: To assess the effectiveness of antidepressants in the treatment of tinnitus and to ascertain whether any benefit was due to a direct tinnitus effect or a secondary effect due to treatment of concomitant depressive states. SEARCH STRATEGY: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) The Cochrane Library Issue 1, 2006); MEDLINE (January 1951 to 2006); EMBASE (1974 to 2006), CINAHL (to 2006), PSYCINFO (to 2006), LILACS (to 2006), and Cambridge Scientific Abstracts. The date of the most recent search was March 2006. SELECTION CRITERIA: Randomised controlled clinical studies of antidepressant drugs versus placebo in patients with tinnitus. DATA COLLECTION AND ANALYSIS: The studies retrieved were critically appraised and data extracted independently by two authors. Where necessary study authors were contacted for further information. MAIN RESULTS: Five trials involving 525 patients were included. Four of these trials looked at the effect of tricyclic antidepressants on tinnitus, investigating 405 patients. One trial investigated the effect of a selective serotonin reuptake inhibitor (SSRI) in a group of 120 patients. No trials involving other antidepressant agents met the inclusion criteria. Only the trial using the SSRI drug met the highest quality standard. None of the other included trials met the highest quality standard, due to use of inadequate outcome measures, large drop out rates or failure to separate the effects on tinnitus from the effects on symptoms of anxiety and depression. All the trials assessing tricyclic antidepressants suggested that there was a slight improvement in tinnitus but these effects may have been attributable to methodological bias. The trial that investigated the SSRI drug found no overall improvement in any of the validated outcome measures that were used in the study although there was possible benefit for a subgroup that received higher doses of the drug. This observation merits further investigation. Reports of side effects including sedation, sexual dysfunction and dry mouth were common. AUTHORS' CONCLUSIONS: There is insufficient evidence to say that antidepressant drug therapy improves tinnitus.

Macroscopic growth of filamentous fungi on solid substrate explained by a microscopic approach.

A quantitative model predicting biomass growth on solid media has been developed. The model takes into account steric interactions between hyphae and tips at the microscopic level (competition for substrate and tip-hypha collisions). These interactions effect a slowing down of the hyphal, population-averaged extension rate and are responsible, at the microscopic level, for the distribution of tip orientations observed at the colony border. At the macroscopic level, a limiting value of the colony radial extension rate is attained. A mathematical model that combines hyphal branching, tip diffusion, and biomass growth was proposed to explain such behavior. Experiments using Gibberella fujikuroi were performed to validate the model; good agreement between experiments and simulations was achieved. Most parameters can be measured by simple image analysis on the peripheral growth zone, and they have clear physical meaning; that is, they correspond to properties of single, leading hyphae. The model can be used to describe two-dimensional (2D) solid media fermentation experiments under varying culture conditions; the model can also be extended to consider growth in three-dimensional (3D), complex geometry substrates.

Determination of cells' water membrane permeability: unexpected high osmotic permeability of Saccharomyces cerevisiae.

Water permeability (Lp), calculated from the volume variations of cells subjected to an osmotic shock, is classically used to characterize cell membrane properties. In this work, we have shown the importance of the kind of mixing reactor used to measure the Lp parameter. A mathematical model including the mixing time constant has been proposed allowing an accurate Lp estimation even though the mixing time constant is higher than the cell time constant obtained in response to a perfect shock. The estimated Lp values of human leukemia K562 cells were found to be the same whatever the mixing time constant. The Lp value of Saccharomyces cerevisiae could not be exactly estimated. However, S. cerevisiae has unexpectedly high water permeability, implying that this yeast may contain water channels in the membrane.

Modeling of continuous Ph-stat stirred tank reactor with Lactococcus lactis ssp. lactis bv. diacetylactis immobilized in calcium alginate gel beads.

A dynamic diffusion-reaction-growth model is proposed for the study of lactic fermentation, the bioconversion of citric acid, and cell release in an immobilized cell reactor [pH-stat continuous stirred tank-reactor (CSTR)]. The model correctly simulates the onset of fermentation and colonization of the gel, followed by the steady state. External diffusion is nonlimiting and internal diffusion is limited by high cell densities at the periphery of the gel beads. Lactose-citrate cometabolism in the gel is related to the distribution of active included biomass within the gel and to gradients of substrates (lactose, citrate) and products (lactate, pH) in the beads. The utilization of lactose is limited by reaction, whereas that of citrate is limited by diffusion. Cell release from gel to the liquid medium occurs in the external spherical cap of the beads. In this peripheral zone viability is maintained at around 90%. (c) 1995 John Wiley & Sons Inc.

Effects of the kinetics of osmotic pressure variation on yeast viability.

The variation rate of the osmotic pressure increase was found to have a great effect on the viability of yeasts subjected to hyperosmotic stress. A low intensity of the increase rate of osmotic pressure could maintain an important viability of the cells (about 90 to 100%) even for very high levels of osmotic pressure (about 10(8) Pa). The viability level was found to be highly dependent on the physiological state of the cells: Variations in the properties of the cell membrane were supposed to be involved in such a dependence.

Direction of hyphal growth: a relevant parameter in the development of filamentous fungi.

Macroscopic and microscopic measurements of the growth of Trichoderma viride and Rhizopus oligosporus were compared at different values of water activity of the solid medium. The relationship between radial extension rate and hyphal growth rate was found to be dependent on water activity. The observed difference between these two parameters was explained by the distribution of apical directions. The validity of the radial extension rate as a growth criterion could be discussed. The angular distribution of apical axes of growth in the front of the colony was observed at different water activity levels of the solid medium, and a model which links radial growth rate to hyphal growth rate and direction of apex growth was proposed and experimentally validated.

Influence of the water activity of a solid substrate on the growth rate and sporogenesis of filamentous fungi.

The water activity (a(w)) of substrates has been related to the mycelial growth and the sporogenesis of two molds. In the absence of other limiting factors, optimal a(w) values were determined for growth and sporogenesis as 0.99 and 0.98, respectively, for Trichoderma viride TS and 0.97 and 0.96 for Penicillium roqueforti. In all cases, the accuracy of the optimal value would justify the regulation of this parameter. A model was proposed which establishes a relationship between the mycelial growth and the water activity value of the substrate.