Delayed Auditory Brainstem Responses (ABR) in children after sight-recovery.

Studies in non-human animal models have revealed that in early development, the onset of visual input gates the critical period closure of some auditory functions. The study of rare individuals whose sight was restored after a period of congenital blindness offers the rare opportunity to assess whether early visual input is a prerequisite for the full development of auditory functions in humans as well. Here, we investigated whether a few months of delayed visual onset would affect the development of Auditory Brainstem Responses (ABRs). ABRs are widely used in the clinical practice to assess both functionality and development of the subcortical auditory pathway and, provide reliable data at the individual level. We collected Auditory Brainstem Responses from two case studies, young children (both having less than 5 years of age) who experienced a transient visual deprivation since birth due to congenital bilateral dense cataracts (BC), and who acquired sight at about two months of age. As controls, we tested 41 children (sighted controls, SC) with typical development, as well as two children who were treated (at about two months of age) for congenital monocular cataracts (MC). The SC group data served to predict, at the individual level, wave latencies of each BC and MC participant. Statistics were performed both at the single subject as well as at the group levels on latencies of main ABR waves (I, III, V and SN10). Results revealed delayed response latencies for both BC children compared with the SC group starting from the wave III. Conversely, no difference emerged between MC children and the SC group. These findings suggest that in case the onset of patterned visual input is delayed, the functional development of the subcortical auditory pathway lags behind typical developmental trajectories. Ultimately results are in favor of the presence of a crossmodal sensitive period in the human subcortical auditory system.

Nanocrystalline lanthanide-doped Lu3Ga5O12 garnets: interesting materials for light-emitting devices.

Nanocrystalline Lu(3)Ga(5)O(12), with average particle sizes of 40 nm, doped with a wide variety of luminescent trivalent lanthanide ions have been prepared using a sol-gel technique. The structural and morphological properties of the powders have been investigated by x-ray powder diffraction, high resolution transmission electron microscopy and Raman spectroscopy. Structural data have been refined and are presented for Pr(3+), Eu(3+), Gd(3+), Ho(3+), Er(3+) and Tm(3+) dopants, while room temperature excited luminescence spectra and emission decay curves of Eu(3+)-, Tm(3+)- and Ho(3+)-doped Lu(3)Ga(5)O(12) nanocrystals have been measured and are discussed. The Eu(3+) emission spectrum shows typical bands due to 5D(0)-->7F(J) (J = 0, 1, 2, 3, 4) transitions and the broadening of these emission bands with the non-exponential behaviour of the decay curves indicates the presence of structural disorder around the lanthanide ions. Lanthanide-doped nanocrystalline Lu(3)Ga(5)O(12) materials show better luminescence intensities compared to Y(2)O(3), Gd(3)Ga(5)O(12) and Y(3)Al(5)O(12) nanocrystalline hosts. Moreover, the upconversion emission intensity in the blue-green region for the Tm(3+)- and Ho(3+)-doped samples shows a significant increase upon 647.5 nm excitation with respect to other common oxide hosts doped with the same lanthanide ions.

[Exposure to low levels of solvents and noise, ear canal volume and audiometric pattern]. / Esposizione a bassi livelli di solventi e rumore volume del condotto uditivo e pattern audiometrico.

We described a case of a male worker, 62 years old, with a combined exposure to low noise levels (80-85 dB Leq,A) and organic solvents mixture for more than 30 years in the automobile industry as a painter. His ear canal has a diameter of more than 1.3 cm. and determine a peculiar pattern of hearing loss, similar to the noise induced one, but chiefly in the speech frequencies. According to experimental and human studies we speculate that in this patient the peculiar morphology of the audiogram, with the low or mean frequencies maximally affected, may been explained by a synergistic effect of solvents mixture in conjunction with noise exposure and a high ear canal volume.

Exhaled nitric oxide and impaired oxygenation in cirrhotic patients before and after liver transplantation.

BACKGROUND: Nitric oxide may be involved in the impaired oxygenation of cirrhotic patients, a condition that improves in most patients after liver transplantation. OBJECTIVE: To compare oxygenation and nitric oxide concentrations before and after liver transplantation. DESIGN: Before-and-after observational study. SETTING: Academic medical center. PATIENTS: 18 patients with cirrhosis and no obvious cardiopulmonary disease who underwent successful orthotopic liver transplantation. INTERVENTION: Orthotopic liver transplantation. MEASUREMENTS: Blood gas analysis, measurement of exhaled nitric oxide, contrast-enhanced echocardiography, and pulmonary function tests. RESULTS: Before transplantation, the mean (+/- SD) exhaled nitric oxide concentration was higher in patients than in normal controls (13 +/- 4.9 parts per billion [ppb] compared with 5.75 +/- 1.9 ppb; P < 0.001). After transplantation, the alveolar-arterial oxygen gradient significantly decreased (from 17.3 +/- 7.1 mm Hg to 9 +/- 5.2 mm Hg; P < 0.001), as did the exhaled nitric oxide concentration (from 13 +/- 4.9 ppb to 6.2 +/- 2.8 ppb; P < 0.001). The decrease in the exhaled nitric oxide concentration was significantly correlated with the decrease in the alveolar-arterial oxygen gradient (r = 0.56; P = 0.014). Five patients met the criteria for the diagnosis of the hepatopulmonary syndrome before transplantation; the syndrome was cured by transplantation. CONCLUSIONS: The correlation between the decrease in exhaled nitric oxide concentration after liver transplantation and the improvement in oxygenation reinforces the hypothesis that nitric oxide is an important mediator of impaired oxygenation in patients with cirrhosis.

Exhaled nitric oxide and oxygenation abnormalities in hepatic cirrhosis.

Impaired arterial oxygenation, ranging from increased alveolar-arterial oxygen gradient (AaDo2) to hypoxemia, is commonly present in patients with cirrhosis. Nitric oxide (NO), through pulmonary vasodilatation, may play a major role in the oxygen abnormalities of cirrhosis. Our aim was to study the relationship between NO production and O2 abnormalities in 45 nonsmoking patients with cirrhosis and without major cardiovascular and respiratory diseases. Intrapulmonary shunting was detected by contrast-enhanced (CE) echocardiography. Lung volumes and diffusion, arterial blood gas analysis, serum NO2-/NO3-, NO output in the exhaled air, and cardiac index by the echocardiographic method were determined in all patients. Twenty-seven (60%) patients had an abnormally increased (> 15 mm Hg) AaDo2. The mean values of exhaled NO output and serum NO2-/NO3- were significantly higher in cirrhotic patients than in controls (252 +/- 117 vs. 75.2 +/- 19 nL/min/m2, P < .0001; and 47.5 +/- 29.4 vs. 32.9 +/- 10.1 micromol/L, P < .02, respectively). In all patients, there was a significant correlation between exhaled NO and AaDo2 (r = .78, P < .0001). Twelve patients (26.6%) were found to have CE-echocardiographic evidence of intrapulmonary shunting (positive CE-echo). Nine patients were considered to have hepatopulmonary syndrome (HPS) on the basis of an AaDo2 > 15 mm Hg and positive CE-echo. These 9 patients had a mean value of exhaled NO significantly higher than patients without HPS (331 +/- 73.2 vs. 223 +/- 118.4 nL/min/m2, P < .05). In all patients, cardiac index was positively correlated with exhaled NO (r = .47, P < .001) and with serum NO2-/NO3- (r = .43, P < .01). The results suggest an important role of NO in the oxygenation and circulatory abnormalities of patients with cirrhosis.

Increased nitric oxide in exhaled air of patients with systemic lupus erythematosus.

OBJECTIVE: In experimental animals, elevated nitric oxide (NO) production has been implicated in the pathogenesis of a lupus-like syndrome. Abnormalities of lung function tests are reported in a high proportion of patients with systemic lupus erythematosus (SLE). We investigated whether NO output in exhaled air might be increased in patients with SLE and whether it is related to disease activity and to respiratory function abnormalities. METHODS: Lung volume, maximal expiratory flow at 50 and 25% of vital capacity (MEF50 and MEF25), diffusion coefficient for carbon monoxide (KCO), and NO in the exhaled air were measured in 27 outpatients with SLE (23 women, age 39.2 +/- 16.3). NO in exhaled air was also measured in 30 healthy control subjects. Disease activity was assessed by the European Consensus Lupus Activity Measurement (ECLAM) scoring system. RESULTS: Mean values of peak concentrations of NO exhaled air were 64.8 +/- 27.9 parts per billion (ppb) in patients and 31.6 +/- 7.7 ppb in controls, p < 0.001. Peak NO concentration was directly related to ECLAM activity score (p < 0.05) and inversely related to MEF25 (p < 0.05). CONCLUSION: NO in exhaled air is significantly increased and correlated with disease activity in patients with SLE. Whether increased NO output depends on respiratory tract inflammation, as the relationship with MEF25 may suggest, or on circulating cytokines produced elsewhere remains to be investigated.

Pentoxifylline attenuates LPS-induced bronchial hyperresponsiveness but not the increase in exhaled nitric oxide.

BACKGROUND: Inhaled endotoxin (LPS) may cause a transient increase in airway responsiveness, possibly through a cytokine-mediated airway inflammation, which is associated with an increase in nitric oxide synthesis and release. OBJECTIVE: We wondered whether pentoxifylline (PTX), which may attenuate cytokine release induced by LPS, could inhibit LPS-induced increase in airway responsiveness. METHODS: Methacholine (Mch) bronchial responsiveness was assessed 2 and 24 h after saline or LPS inhalation in eight subjects with bronchial hyperresponsiveness (PD20FEV1 610 +/- 53 micrograms), treated with iv saline or PTX, in a double-blind crossover design. Nitric oxide (NO) in the exhaled air, which was expected to increase after LPS inhalation, and PEFR values were also measured at baseline, hourly for 6 h and 24 h later. RESULTS: After LPS inhalation PEFR decreased significantly compared with placebo inhalation, reaching a maximum decrease of 11.25 +/- 1.05 and 4.5 +/- 0.84% of baseline, at 2 h, respectively during saline and PTX infusion, P < 0.001. Exhaled NO were elevated after LPS compared with placebo inhalation at 1 h (35.6 +/- 4.8 vs 18 +/- 2.8 ppb, P < 0.001), with no difference during saline or PTX infusion. Exhaled NO remained elevated until the 6th hour. PD20FEV1 2h after LPS inhalation was significantly lower than after placebo inhalation both during saline infusion (234 +/- 29 vs 625 +/- 62 micrograms, P < 0.001) and during PTX infusion (441 +/- 47 vs 616 +/- 48 micrograms, P < 0.001), the difference between saline and PTX being significant (P < 0.01). At 24 h no difference in PEFR, PD20FEV1 and exhaled NO was observed in comparison with pre-study values. CONCLUSION: PTX attenuates both the decrease in airway patency and the increase in bronchial responsiveness induced by LPS inhalation, without any significant change in exhaled NO, which is increased by LPS inhalation.

Myocardial ischemia alters immunoregulatory cell traffic and function in the rat independent of exogenous catecholamine administration.

Recent investigation has suggested there is an adrenergically-driven efflux of beta 2-receptor rich lymphocyte subsets into the circulation with altered function following either exercise or infusion of exogenous catecholamines. Myocardial ischemia, like exercise, is associated with generalized sympathoadrenal activation. To determine whether ischemia influences immunoregulatory cell traffic and function in a manner comparable to beta 2-adrenergic stimulation via isoproterenol, rats underwent thoracotomy with or without coronary ligation. Another group of rats received either isoproterenol (1 mg/kg) or vehicle (10 mM HCl) intraperitoneally. Thoracotomy, regardless of whether or not myocardial ischemia was induced, led to lymphocytosis, reflected primarily by an increase in Thelper (Th) cells and, to a lesser degree, in Tsuppressor/cytotoxic (Ts/c) and natural killer (NK) cells, with a tendency toward an increased Th/Ts/c ratio. To the contrary, isoproterenol injection resulted in a relative lymphopenia characterized by diminished B and Th cell numbers, preserved Ts/c and increased NK cell numbers leading to a significant decrease in the Th/Ts/c ratio. With respect to splenic composition, 60 but not 15 min of myocardial ischemia led to diminished Th and B cell numbers compared to sham operated controls, whereas isoproterenol appeared to stimulate an efflux of only NK cells. Both ischemia and isoproterenol enhanced basal splenocyte function; however, only ischemia significantly boosted splenocyte responsiveness to the mitogen Concanavalin A. Surgically induced myocardial ischemia leads to alterations in immunoregulatory cell migration and function which are distinct from those found with beta 2-adrenergic stimulation via isoproterenol.

Prolonged isoproterenol treatment alters immunoregulatory cell traffic and function in the rat.

The mechanisms by which the sympathetic nervous system modulates functional parameters of the immune system have not been fully defined. In vivo, acute and chronic beta 2-adrenergic stimulation have been shown to have dramatic but opposing effects on circulating lymphocyte number and subset distribution in humans. In vitro studies have suggested impairment of numerous lymphocyte effector functions in the presence of catecholamines. To better define the effects of short and long term beta-adrenergic stimulation on lymphocyte migration patterns between circulating and splenic pools, as well as function, we infused rats with either low or high doses of isoproterenol over various time intervals. Specifically, we determined the number and subset composition of peripheral blood and splenic lymphocytes in addition to assessing responsivity to the T cell mitogen concanavalin A and antibody production. As a measure of in vivo lymphocyte proliferation, we also monitored the effect of these infusions on the number of peripheral blood lymphocytes and splenocytes and the splenic weight. Isoproterenol led to dose-dependent, short-lived decrements in mitogen-induced lymphocyte proliferation with concomitant decreases in circulating and splenic lymphocyte number in a subset-specific manner. Analysis of the distribution of circulating and splenic subtypes with isoproterenol treatment suggests definite but limited influences on beta-adrenergic stimulation on immunoregulatory cell traffic. We conclude that beta-adrenergic stimulation in the rat model leads to a dose-dependent, transient effect on lymphocyte proliferation and migration patterns. The relative lack of functional beta-receptors on rat lymphocytes and the propensity for early sustained receptor desensitization on exposure to agonist may account for qualitative differences seen between rats and humans.

Does verapamil act as an immunomodulatory drug in vivo?

Based on in vitro data, previous investigators have hypothesized that Ca2+ entry blockers might affect lymphocyte activation, proliferation and effector function. We have tested this hypothesis by comparing the in vitro and in vivo effects of the Ca2+ entry blocker verapamil on human lymphocytes. In vitro high concentrations of verapamil (100 microM) inhibited mitogen-stimulated Ca2+ influx, inositol phosphate generation, and proliferation; similar effects were observed with diltiazem and nifedipine. In vivo treatment of healthy volunteers with verapamil (2-4 times 240 mg per day for 7 days) did not affect the number of circulating lymphocytes or their subset distribution. Moreover, we did not observe any effect of in vivo treatment with verapamil on mitogen-stimulated lymphocyte proliferation or expression of interleukin-2 receptors in vitro. We conclude that the inhibitory effects of verapamil on lymphocyte activation in vitro are unlikely to be of therapeutic relevance and may not be related to the Ca2+ entry blocking effects of this drug.

Short-term respiratory changes in polyurethane foam workers exposed to low MDI concentration.

Our study included 27 polyurethane foam workers exposed to MDI only at low concentrations (ranging from 0.0005 to 0.001 ppm) and 27 clerks from the same factory matched by age. Respiratory function tests were performed on a Monday and Friday of the same week at shift onset, 4 h later and at shift end. The subjects under study were asymptomatic for asthma. The two groups had quite similar spirometric values with minimal functional impairment. A statistical analysis was carried out by Student's t-test for matched pairs and two-way analysis of variance (ANOVA), in order to take into account both occupational exposure and smoking habits. No significant differences between the two groups were observed with paired t-tests in the respiratory parameter trend during both the Monday and Friday work shift. Nor were differences observed within the two groups when Friday's and Monday's results were compared. No significant differences between the two groups were found in paired comparisons between Friday and Monday for respiratory parameters. ANOVA demonstrated that the FEV1 and FEF25-75 reduction present on Friday, when compared to Monday, was related to smoking and not to occupational exposure. In conclusion our findings showed no short-term respiratory changes in subjects exposed to low MDI concentration.

[Functional compromise of the small airways in subjects exposed to SiO2]. / Compromissione delle piccole vie aeree nei soggetti esposti a SiO2.

Aims of our study were: to evaluate small airway function of subjects with past or present silica dust exposure and normal spirometric values; to investigate whether small airway disease is related to radiographic signs of silicosis, to cumulative dust exposure (ES) and to cigarette smoking. Maximal expiratory flow at 50% (MEF50) and 25% (MEF25) of forced expired vital capacity were measured in 112 subjects, 69 with radiographic signs of silicosis, group I, and the remaining 43 with normal chest X-rays. Even if age and ES were significantly higher in group I, no significant difference in respiratory function tests and in prevalence of small airway disease was found between the two groups. In both groups small airway function was significantly negatively related to smoking habits, while it was independent of the other variables considered. Multiple regression analysis with MEF50 and MEF25 as dependent variables did not show any significant relationship. We conclude that small airway disease due to encroachment of bronchiolar walls by SiO2 deposition is masqued by the damage produced by cigarette smoking, even in the presence of radiographic signs of silicosis.

Site of airway obstruction after rapid saline infusion in healthy subjects.

Static and dynamic lung volumes, flow-volume curve in air and after He-O2 were carried out in 5 normal subjects baseline, immediately after rapid infusion of 2 litres of normal saline, and then 15, 30 and 60 min after. At the end of the infusion, a marked reduction of delta MEF50, FVC, FEV1, MEF50, MEF25 and an increase of Viso V and CV/VC were observed in all the subjects. The poor response to He-O2 suggests a predominant increase of small airway resistance after rapid infusion. In the recovery phase, He-O2 tests promptly returned to control values, while an increased CV/VC was detectable until 30 min after the infusion.