Does blue-violet filtering in contact lenses improve contrast sensitivity?

PURPOSE: The work is aimed at (i) comparing photopic contrast sensitivity (CS) of healthy subjects in an indoor environment with either blue-violet filtering (BVF) or clear contact lenses (CLs) and (ii) investigating a possible dependence of the CS variation on the subjects' intrinsic CS, measured with clear CLs. METHODS: Optical transmittance of BVF and clear CLs was measured by a spectrophotometer. Photopic CS was measured monocularly on forty-one subjects (nineteen in the age range 20-36 years and twenty-two in the age range 44-66 years) by a digital optotype system at spatial frequencies from 1.5 to 18 cpd, wearing either clear or BVF CLs. The results are indicated as CSclear and CSBVF, respectively. RESULTS: Transmittance curves in the visible range of the two CLs are very similar, despite an absorption band in the BVF CL spectrum with the minimum of transmittance at 428 ± 4 nm equal to about 79%. For both CSclear and CSBVF, no significant CS difference was found between younger and older adults. The difference [log(CSBVF) - log(CSclear)] showed a decreasing trend and changed sign from positive to negative as a function of log(CSclear) with correlation Spearman's Rho coefficients ranging from 0.80 to 0.88 (p < 0.01 at all spatial frequencies). CONCLUSION: In the choice of a BVF CL, practitioners should take into consideration that it can influence photopic CS, improving it for subjects who have a relatively low CS with clear CLs, and worsening it for subjects who have a relatively high CS with clear CLs. BVF can affect positively the CS by reducing intraocular scattering. However, it can also cause a reduction in light intensity, which contributes to the formation of the retinal image. The positive or negative influence of BVF CLs compared to clear ones on CS is attributed to a balance among these effects.

Nutrient depletion modifies cell wall adsorption activity of wine yeast.

Yeast cell wall is a structure that helps yeasts to manage and respond to many environmental stresses. The mannosylphosphorylation is a modification in response to stress that provides the cell wall with negative charges able to bind compounds present in the environment. Phenotypes related to the cell wall modification such as the filamentous growth in Saccharomyces cerevisiae are affected by nutrient depletion. The present work aimed at describing the effect of carbon and/or nitrogen limitation on the aptitude of S. cerevisiae strains to bind coloured polyphenols. Carbon- and nitrogen-rich or deficient media supplemented with grape polyphenols were used to simulate different grape juice conditions-early, mid, 'adjusted' for nitrogen, and late fermentations. In early fermentation condition, the R+G+B values range from 106 (high adsorption, strain Sc1128) to 192 (low adsorption, strain Σ1278b), in mid-fermentation the values range from 111 (high adsorption, strain Sc1321) to 258 (low adsorption, strain Sc2306), in 'adjusted' for nitrogen conditions the values range from 105 (high adsorption, strain Sc1321) to 194 (low adsorption, strain Sc2306) while in late fermentation conditions the values range from 101 (high adsorption, strain Sc384) to 293 (low adsorption, strain Sc2306). The effect of nutrient availability is not univocal for all the strains and the different media tested modified the strains behaviour. In all the media the strains show significant differences. Results demonstrate that wine yeasts decrease/increase their parietal adsorption activity according to the nutrient availability. The wide range of strain variability observed could be useful in selecting wine starters.

Viability of commercial wine yeasts during freezer storage in glycerol-based media.

Glycerol-based medium (BM) with and without the addition of 1 g/L ascorbic acid (Asc) and/or 100 mg/L (+/-)-catechin (Cat) was tested for the storage of three commercial wine yeasts at -20 degrees C. The medium supplemented with Asc was also used to store 706 strains to verify the maintenance of the liquid state. A decline in survival throughout the storage period was observed. The media containing Asc maintained viability better than the other three. The BM caused a loss of viability of 7 orders for one strain and of 6 orders for the other two. All three strains exhibited a loss of viability of 4 orders when stored in BM+Asc. Two strains decreased viability by 5 orders while one strain by 4 orders, when stored in BM+Cat. Two strains decreased viability by 6 orders while one strain by 5 orders, when stored in BM+Asc+Cat. Regarding the physical state of the medium tested on 706 yeast strains, three cases were observed: completely liquid (56.5 %), liquid with only the upper part frozen (40.4 %) without involving the yeast biomass settled at the bottom, and completely frozen (3.12 %). It is practicable to prepare a BM that remains liquid at -20 degrees C enhancing yeast viability when Asc is added as cryoprotectant.

Wine colour adsorption phenotype: an inheritable quantitative trait loci of yeasts.

AIMS: In this work, a population of 88 descendants derived from three wine strains of Saccharomyces cerevisiae was tested for the enological trait 'wine colour adsorption' (WCA) to evaluate its inheritability. METHODS AND RESULTS: The WCA phenotype was tested on plate agar medium specifically formulated for the purpose. After 10 days of anaerobic incubation at 28 degrees C, a computer-assisted assessment of WCA aptitude of the yeasts was carried out. The biomass colour -- ranging from white to dark brown -- reflects the adsorption of grape pigments: white and dark brown biomass colour corresponds to low and high adsorption, respectively. In order to confirm biomass colour results, microvinification trials using red must were performed, and the obtained wines were analysed. CONCLUSIONS: The analysis of the progeny demonstrated that the enological trait WCA is inheritable and polygenic. SIGNIFICANCE AND IMPACT OF THE STUDY: A way to describe the polygenic effect of the WCA trait has been found, also showing that this trait is inheritable. The impact of the work revolves more around the large-scale screening method, which could then assist in breeding wine yeast, and can also be used as a scientific tool to investigate WCA trait.

HPLC determination of phenolics adsorbed on yeasts.

An analytical HPLC method was developed to determine monomeric anthocyans as catechin (CA), flavonols as rutin (RU) and phenol acids as gallic acid (GA) adsorbed on the cell wall of 23 Saccharomyces cerevisiae strains grown on two media containing high levels of phenolic compounds, from grape seeds and grape skins, and on one control medium. Microbial biomass purification by liquid-liquid extraction of the phenolics is followed by reversed-phase chromatographic separation and CA, RU and GA detection by ultraviolet detector. The method was linear over the studied range of concentrations: GA at 0.12-0.96 microg/ml, CA at 0.25-20.00 microg/ml and RU at 0.02-0.20 microg/ml. The correlation coefficient for each analyte was greater than 0.9983. The recovery was greater than 85% for both GA and RU, and greater than 94% for CA. The detection limits for GA, CA and RU were determined to be 0.015, 0.025 and 0.029 microg/mg of biomass, respectively. The proposed method is highly responsive for the determination of different phenolics, and seems to be useful to evaluate their adsorption profile on yeasts.

Selection of Escherichia coli-inhibiting strains of Lactobacillus paracasei subsp. paracasei.

The aim of this study was to select Escherichia coli-inhibiting strains among lactic acid bacteria. On the basis of phenotypical and technological characteristics, 20 strains of lactic acid bacteria were screened from a total of 225 isolates, obtained from nine samples of artisanal Caprino d'Aspromonte cheese, made from raw goats' milk. The antagonistic activity of these 20 strains was detected in plates against three different strains of E. coli. Two strains of Lactobacillus paracasei subsp. paracasei showed a marked anti-E. coli activity against all three strains tested; the other lactic acid bacteria did not exhibit inhibiting activity. The E. coli inhibition can be ascribed to production of bacteriocin-like compounds. The use of L. paracasei subsp. paracasei strains to increase the safety of the cheeses made from raw milk is recommended because these cultures strongly inhibit E. coli, without foreseeable adverse sensory changes.

Winemaking from Gaglioppo grapes with hybrid strains of Saccharomyces.

The fermentative behavior of two hybrid wine yeast strains (first-generation hybrid-strain 12,233 x 6167--obtained by hybridization of the cryotolerant strain S. bayanus 12,233 with the mesophilic strains S. cerevisiae 6167, and TT254 x 6392 arising by hybridization of the thermotolerant strain S. cerevisiae TT254 with the mesophilic strain S. cerevisiae 6392) was compared with that of a commercial wine yeast strain S. cerevisiae K1 in must from black grapes of the Calabrian variety Gaglioppo. The goal was to obtain wines with a high content of 'polyphenols' from a grape must with a limited phenolic content such as the Gaglioppo must. The progress of the winemaking was estimated according to residual sugars; at the end of fermentation, the wines were decanted, bottled and principal physico-chemical characteristics determined. Our results point to the possibility to select wine yeasts (significantly differing in the above parameters) by their ability to interact with phenolic compounds.

Protective agents used to reverse the metabolic changes induced in wine yeasts by concomitant osmotic and thermal stress.

AIMS: The reversion of the metabolic changes induced in wine yeasts by stressors. METHODS: Six strains of Saccharomyces were inoculated in grape must containing over 400 g l-1 of sugar and incubated at 35 degrees C, both with and without the addition of 100 mg l-1 of catechin, inositol or SO2. RESULTS: Significant correlations between addition of the stress-protectants and change in the metabolic behaviour of the wine yeasts were observed. Depending on strain and protectant, and expressing data as a percentage of increase or decrease compared to the control, fermentation vigour after 3 d increased by up to 10%, titratable acidity of the wines increased by up to 7%, ethanol content increased by up to 20%, unitary acetic acid production decreased by up to 35%, and unitary glycerol production decreased by up to 20%. IMPACT OF STUDY: By using protective agents it is possible to minimize the abnormal fermentation performance that wine yeasts exhibit under thermal and osmotic stress.

[Transient osteoporosis of the hip in magnetic resonance imaging]. / Aspetti dell'osteoporosi transitoria dell'anca con Risonanza Magnetica.

This study was aimed at assessing the MR patterns of transient osteoporosis of the hip and, consequently, the role of MRI in the diagnosis and follow-up of this condition. Even though this condition was originally observed in pregnant women, young or middle-aged men are most frequently affected. There is a spontaneous onset of pain, usually progressing over several weeks. The patients have no risk factors for osteonecrosis; they may have a history of minor trauma and there is a possible relationship to the third trimester of pregnancy. Laboratory values are negative. Pain may be severe enough to cause the patient to limp and to impair joint function. The possible causes of transient osteoporosis have been debated by many authors and include trauma, synovitis, neurovascular dysfunction and transient or reversible ischemia. Transient osteoporosis is a self-limiting disease which does not require surgical treatment. The differential diagnosis of transient osteoporosis of the hip is very important because this condition may simulate cancer, septic arthritis, osteomyelitis or avascular necrosis. We report the initial and follow-up features of transient osteoporosis of the hip on the MR images of 6 patients (M/F = 5/1; age: 37-49 years, mean: 41.8 years). The right side was involved in 3 patients, the left side in 2 patients. The patient with bilateral transient osteoporosis was a woman in the 3rd trimester of pregnancy. In all patients, MRI was performed with an 0.5 T MR unit. The MR changes in our 6 patients were rather uniform and included heterogeneous decrease in the signal intensity of the affected bone marrow on T1-weighted images and increased signal intensity on T2-weighted and STIR images, with no evidence of focal lesions. This pattern is known as the "bone marrow edema" (BME) pattern. All the patients received conservative treatment. The clinical symptoms and the MR abnormalities regressed completely within 6-10 months, with no late sequelae. To conclude, this follow-up MR study demonstrates the transient, reversible character of transient osteoporosis of the hip. Until the natural history of the BME pattern is better understood, we suggest a conservative management of this condition, especially in the patients with no risk factors for osteonecrosis. Radiographic and MR follow-up is recommended.

Ritmo circadiano y accidente cerebrovascular / Stroke and circadian rhythm

La variación diaria en la aparición de Accidente Cerebro Vascular (ACV) fue examinada en 255 pacientes. Estos incluyeron 173 isquemias y 82 hemorragias intraparenquimatosas (HI). Los pacientes fueron ordenados en despiertos y dormidos, y distribuidos en 4 períodos de 6 horas cada uno. La frecuencia de aparición de ACV isquémico fue significativa (p<0,001) para el período de 08 a 14 horas (46,6%); para las HI también fue significativa (p<0,001) para el mismo período (46,3%). Se analizaron otras variables: edad, sexo y tipo de lesión relacionándolas con el estado del paciente (despierto-dormido) y con el momento (día-noche) en que ocurrió el ACV. El análisis de los pacientes con ACV isquémico y hemorrágico con manifestación al despertar mostró una frecuencia significativa (p<0,001) para las isquemias (81,3%) que para las HI (18,7%)

Ritmo circadiano y accidente cerebrovascular / Stroke and circadian rhythm

La variación diaria en la aparición de Accidente Cerebro Vascular (ACV) fue examinada en 255 pacientes. Estos incluyeron 173 isquemias y 82 hemorragias intraparenquimatosas (HI). Los pacientes fueron ordenados en despiertos y dormidos, y distribuidos en 4 períodos de 6 horas cada uno. La frecuencia de aparición de ACV isquémico fue significativa (p<0,001) para el período de 08 a 14 horas (46,6%); para las HI también fue significativa (p<0,001) para el mismo período (46,3%). Se analizaron otras variables: edad, sexo y tipo de lesión relacionándolas con el estado del paciente (despierto-dormido) y con el momento (día-noche) en que ocurrió el ACV. El análisis de los pacientes con ACV isquémico y hemorrágico con manifestación al despertar mostró una frecuencia significativa (p<0,001) para las isquemias (81,3%) que para las HI (18,7%)

[Anticipatory anxiety and interpersonal relations with the radiologist of patients undergoing diagnostic imaging]. / Ansia anticipatoria e rapporto interpersonale con il medico radiologo nei pazienti sottoposti a diagnostica per immagini.

A pilot study has been carried out with the aim of evaluating the impact of updated imaging techniques (CT and MRI) versus "simple" examinations (tomography, X-rays, US, and nuclear medicine) on the anticipatory anxiety of the patients, as well as on the radiologist-patient relationship. Ninety consecutive patients undergoing diagnostic imaging modalities were examined according to the following schedule: 1) preliminary interview and anxiety assessment according to HRSA; 2) diagnostic imaging investigation, and 3) filling out an "ad hoc" questionnaire. The collected data have been divided into two groups: the "simple" group (52 patients submitted to X-rays, tomography, US, and nuclear medicine), and the "complex" group (38 patients submitted to CT and MRI). Anticipatory anxiety was observed in all subjects and attained psychopathological rates in more than half of them. Anxiety proved to be related to the completion of the examination rather than to its complexity. The questionnaire has pointed out the need for a more interactive relationship between radiologist and patient during diagnostic imaging examinations.