Linezolid treatment for gram-positive infections: a retrospective comparison with teicoplanin.

In randomized studies linezolid, indicated for Gram-positive infections, was as effective as teicoplanin in critical ill patients or was superior to teicoplanin in skin infection, pneumonia and bacteremia. We performed a 2-year comparative, retrospective study of patients treated with linezolid or teicoplanin in a single hospital for the same indications. We collected information about the type of infection, the responsible pathogen, therapy administered before study drugs, antibiotic associated with the study drugs, length of hospital stay (LOS), adverse events and outcome of the infections. The aim of the study was to evaluate the efficacy of linezolid in this retrospective patients series. Overall we identified 169 patients treated with linezolid and 91 with teicoplanin. Response to therapy, (resolution or improvement of infection) was better in patients treated with linezolid compared to teicoplanin (83.9% versus 69.2%, p=0.002). Response to therapy by type of pathogen showed the superior efficacy of linezolid against Staphylococcus aureus (including MRSA) and enterococci; although not statistically significant because of the small number of patients enrolled, they were close to significance (p<0.056 for S. aureus, p<0.055 for MRSA, p<0.061 for enterococci). Overall LOS in linezolid-treated patients was 4.6 days (p<0.041) less. Empirical use of linezolid reduced lOS by 6 days (p<0.038), especially in VAP and bacteremia patients (p<0.05). Mortality due to infection was 9.8% in both groups, and adverse events were most frequently documented in linezolid-treated patients. Linezolid was clinically superior to teicoplanin in the treatment of Gram-positive infections.

Spatiotemporal integration of light by the cat X-cell center under photopic and scotopic conditions.

Visual responses to stimulation at high temporal frequency are generally considered to result from signals that avoid light adaptive gain adjustment, simply reflecting linear summation of luminance. Under conditions of high photopic illuminance, the center of the receptive field of the cat X-cell has been shown to expand in size when stimulated at high temporal frequency, raising the possibility that there is spatiotemporal interaction in luminance summation. Here we show that this expansion maintains constant the product of the center's luminance summing area and the temporal period of luminance modulation, implying that spatial and temporal integration of luminance can be traded for one another by the X-cell center. As such the X-cell has a spatiotemporal window for luminance integration that fuses the classical concepts of a spatial window of luminance integration (Ricco's Law) with a temporal window of luminance integration (Bloch's Law). We were interested to determine whether this tradeoff between spatial and temporal summation of luminance occurs also at lower light levels, where the temporal-frequency bandwidth of the X-cell is narrower. We found that it does not. Center radius does not expand with temporal frequency under either low photopic or scotopic conditions. These results are discussed within the context of the known retinal circuitry that underlies the X-cell center for photopic and scotopic conditions.

Effects of remote stimulation on the mean firing rate of cat retinal ganglion cells.

Visual stimulation outside the classical receptive field can have pronounced effects on cat retinal ganglion cells. We characterized the effects of such stimulation by varying the contrast, spatial frequency, temporal frequency, and spatial extent of remote drifting sinusoidal gratings. We found that the mean firing rate of some X-cells and most Y-cells increased to remote gratings of low spatial frequency and high temporal frequency and decreased to ones of high spatial frequency and low temporal frequency. At least 10-20% contrast was required to see either effect, which quickly saturated at higher contrasts. Both effects were substantial, raising or lowering the mean rate of some cells by over 40 impulses/sec. Classical receptive field mechanisms were not involved because the remote gratings caused little or no response modulation. We conclude that, in addition to a mean-increasing mechanism known from previous work, a mean-decreasing one operates in the cat retina. This mechanism prefers slower motion and resolves finer patterns than the mean-increasing one. We incorporate these findings into a model consisting of pools of small and large rectifying subunits of opposite polarity. Model estimates of subunit radius were primarily independent of eccentricity and averaged approximately 0.15 and approximately 0.60 degrees for the mean-decreasing and mean-increasing mechanisms, respectively. This makes the subunits approximately the center size of central X- and Y-cells. Because smooth movements of the eyes, head, or body should engage these mechanisms under natural conditions, we propose that the mean rate changes that would ensue are functionally relevant to cat vision.

Binge eating disorder: prevalence and psychopathological features in a clinical sample of obese people in Italy.

Binge eating disorder (BED) is a recently conceptualized eating disturbance, and its clinical features and prevalence are still a matter of debate. This study uses interview methodology to estimate the prevalence of BED in Italy in a sample of 66 obese people presenting for treatment, and examines potential related features typical of patients with anorexia and bulimia nervosa. The lifetime and the 6-month prevalences of BED were 18.1 and 12.1%, respectively. Breaking the group down on the basis of the current as well as lifetime presence of BED, we found that the weight and shape primary to self-esteem, and the interpersonal distress related to body image, were associated with lifetime BED (P<0.05). All-or-none thinking about food and dieting was typical of BED patients as a whole, either current (P<0.01) or remitted (P<0.05). We discuss two important findings from our study: (a) the key role of self-esteem depending upon weight and shape in discriminating the eating-disordered obese from non-eating-disordered individuals; and (b) the need to explore the whole lifespan when screening for BED, so pointing to the state-trait issue.

Cell-based model of the Limulus lateral eye.

We present a cell-based model of the Limulus lateral eye that computes the eye's input to the brain in response to any specified scene. Based on the results of extensive physiological studies, the model simulates the optical sampling of visual space by the array of retinal receptors (ommatidia), the transduction of light into receptor potentials, the integration of excitatory and inhibitory signals into generator potentials, and the conversion of generator potentials into trains of optic nerve impulses. By simulating these processes at the cellular level, model ommatidia can reproduce response variability resulting from noise inherent in the stimulus and the eye itself, and they can adapt to changes in light intensity over a wide operating range. Programmed with these realistic properties, the model eye computes the simultaneous activity of its ensemble of optic nerve fibers, allowing us to explore the retinal code that mediates the visually guided behavior of the animal in its natural habitat. We assess the accuracy of model predictions by comparing the response recorded from a single optic nerve fiber to that computed by the model for the corresponding receptor. Correlation coefficients between recorded and computed responses were typically >95% under laboratory conditions. Parametric analyses of the model together with optic nerve recordings show that animal-to-animal variation in the optical and neural properties of the eye do not alter significantly its response to objects having the size and speed of horseshoe crabs. The eye appears robustly designed for encoding behaviorally important visual stimuli. Simulations with the cell-based model provide insights about the design of the Limulus eye and its encoding of the animal's visual world.

Deciphering a neural code for vision.

Deciphering the information that eyes, ears, and other sensory organs transmit to the brain is important for understanding the neural basis of behavior. Recordings from single sensory nerve cells have yielded useful insights, but single neurons generally do not mediate behavior; networks of neurons do. Monitoring the activity of all cells in a neural network of a behaving animal, however, is not yet possible. Taking an alternative approach, we used a realistic cell-based model to compute the ensemble of neural activity generated by one sensory organ, the lateral eye of the horseshoe crab, Limulus polyphemus. We studied how the neural network of this eye encodes natural scenes by presenting to the model movies recorded with a video camera mounted above the eye of an animal that was exploring its underwater habitat. Model predictions were confirmed by simultaneously recording responses from single optic nerve fibers of the same animal. We report here that the eye transmits to the brain robust "neural images" of objects having the size, contrast, and motion of potential mates. The neural code for such objects is not found in ambiguous messages of individual optic nerve fibers but rather in patterns of coherent activity that extend over small ensembles of nerve fibers and are bound together by stimulus motion. Integrative properties of neurons in the first synaptic layer of the brain appear well suited to detecting the patterns of coherent activity. Neural coding by this relatively simple eye helps explain how horseshoe crabs find mates and may lead to a better understanding of how more complex sensory organs process information.

[Short term assessment of anthropometric indices and metabolic parameters in obese subjects treated with acarbose]. / Valutazione (a breve termine) del comportamento degli indici antropometrici e dei parametri bioumorali in soggetti obesi trattati con acarbosio.

Acarbose represents the first of a new class of oral antidiabetic drugs: the alpha-glucosidases inhibitors. This drug in fact delays the production of monosacchtarides inhibiting the alpha-glucosidases of the small bowel, that are responsible of digestion of complex polysaccharides and sucrose. In patients with insulin dependent diabetes mellitus (IDDM) acarbose, significantly reduces the postprandial blood glucose levels, and improves the symptoms associated with nocturnal hypoglycaemia reducing the daily insulin dosage. Furthermore acarbose ameliorates the glycemic control of obese patients when associated with hypocaloric diet. The aim of our study has been to value the effectiveness of acarbose 300 mg/day for 12 weeks in patients affected by moderate obesity (30 < - BMI < 40) and with impaired glucose tolerance (IGT). We have studied 12 patients, 6 have been treated with acarbose and hypocaloric diet, while the other 6 have been treated only with diet, these last formed the control group. Before and after the treatment, anthropometric indexes and haematologic parameters have been observed. Patients treated with acarbose presented a significative decrement of body weight, BMI, fat free mass, fat mass and of basal and peak glycaemic values after oral glucose tolerance test (OGTT). Serum lipid values, insulin levels during OGTT and blood pressure presented a not significative improvement. Gastrointestinal symptoms such as flatulence and borborygmus have been reported only in the patients treated with acarbose. The incidence of these reactions usually decreases with time.

[Doppler echocardiography in the functional evaluation of patients with pure mitral valve stenosis]. / Ruolo dell'ecocardiografia Doppler nella valutazione funzionale dei pazienti con stenosi mitralica pura.

To evaluate the utility of echo-Doppler (ED; PW, CW and color), 67 patients affected by pure mitral stenosis (20 M, 47 F, mean age 52 years) were submitted to ED examination. Right and left cardiac catheterization were performed in 20 patients within 24 hours before ED. Mitral area obtained by Doppler method (Hatle's formula) correlated highly with both echo-2 dimensional and hemodynamic area (r = 0.93, p less than 0.001; r = 0.95, p less than 0.001 respectively). It was possible to calculate systolic pulmonary pressure, in patients with tricuspid incompetence, (43.9 +/- 14.9 mmHg, range 25-80) which correlated significantly (r = 0.95, p less than 0.001) with hemodynamic data (40.2 +/- 12.7 mmHg, range 20-70). The left atrial-left ventricular pressure gradient was 15.6 +/- 6.9 mmHg, range 6-32; the mean pressure gradient was 8.4 +/- 3.7 mmHg, range 3-17; the pressure half time 170.2 +/- 62.3 ms, range 83-330. We observed different types of direction of transmitral jets: centrally directed (n = 34); forward antero-lateral wall (n = 28); toward interventricular septum (n = 5). The transmitral jets presented 4 different appearances: scimitar-shaped (n = 28); candle flame (n = 24); mushroom (n = 9); double-jets (n = 6). No correlation was observed between the different types of transmitral jets (direction and appearance) and the parameters obtained by Doppler (PW and CW): velocities, pressure half-time, gradients. Thus, Doppler echocardiography permits a complete anatomic and functional evaluation of patients with pure mitral stenosis. We have not observed any correlation between the hemodynamic data and the different types of transmitral jets visualized by color Doppler.