Effect of biological factors on latency of pattern-reversal visual evoked potentials associated with cathode ray tubes and liquid crystal display monitors in normal young subjects.

PURPOSE: Owing to several factors, peak latencies of pattern-reversal visual evoked potentials (p-VEP) are delayed when viewing liquid crystal display (LCD) monitors compared to those evoked when viewing cathode ray tube (CRT) monitors. However, few studies have examined whether biological factors affect latency in LCD. This study aimed to investigate whether biological factors caused latency changes in LCD among young subjects. METHODS: Twenty-eight subjects (56 eyes) aged 21-29 years (mean ± SD, 22.7 ± 1.7) participated in this study. We recorded output from each eye twice for both CRT and LCD monitors under the same conditions for monocular p-VEP. The peak latencies of three components (N75, P100, and N145) were compared between these two monitors. RESULTS: All peak latencies recorded with LCD were delayed compared to those recorded with CRT: N75, 9.7 ± 2.5 ms; P100, 10.1 ± 3.0 ms; and N145, 8.4 ± 6.2 ms (all p < 0.001). The degree of latency delay varied depending on the components. Moreover, all peak latencies of CRT appeared earlier than standard values of N75, P100, and N145. CONCLUSIONS: These findings suggest that the following aspects should be considered when assessing biological factors that may affect latency: components might influence latency changes; a young age could be related to an early appearance of peak latencies; inter-individual differences might cause latency change. These biological factors should be considered as possible causes for the varying latencies in an LCD monitor. Further studies should include healthy adults with a wider age range to assess the effects of age on latency.

A new noninvasive method for measurement of dynamic lung compliance from fluctuations on photoplethysmography in respiration.

Lung compliance is important in interstitial lung disease (ILD). However, the measurement requires placement of an esophageal pressure probe and is therefore not done in routine clinic practice. This study was performed to develop and verify a new noninvasive method for estimation of dynamic lung compliance (Cdyn) with a photoplethysmograph (PPG) of pulse wave represented as the changes of absorbance of green LED for hemoglobin and to examine its usefulness. A system for measuring Cdyn in combination with changes in estimated pleural pressure (Ppl) from the fluctuations on PPG with respiration and lung volume measured simultaneously by spirometry was developed and verified to show correspondence with the estimated Ppl and the esophageal pressure (Pes), estimated Cdyn, and Cdyn measured with an esophageal balloon. Furthermore, the estimated percentage of predicted Cdyn (%Cdyn) was compared among healthy subjects (HS) (n = 33) and patients with chronic obstructive pulmonary disease (COPD) (n = 31) and ILD (n = 30). Both estimated Ppl and Cdyn were significantly correlated with Pes (r = 0.89) and measured Cdyn (r = 0.63), respectively. The estimated %Cdyn in ILD showed significantly lower values than those in HS and COPD. The estimated %Cdyn was significantly related to percentage of predicted vital capacity (VC) (r = 0.57, P < 0.01) and percentage of predicted diffusion capacity of carbon monoxide (DlCO) (r = 0.50, P < 0.01) in patients with ILD. These findings suggested that the newly developed noninvasive and convenient method for Cdyn estimation using a combination of PPG and spirometry may be useful for the assessment of lung fibrosis in ILD.NEW & NOTEWORTHY Our newly developed method for measuring dynamic lung compliance (Cdyn) in combination with changes in estimated intrathoracic pressure from fluctuations on photoplethysmography with respiration and lung volume measured simultaneously by spirometry showed good linear regression between the estimated Cdyn and the Cdyn measured with an esophageal balloon, and the estimated percentage of predicted Cdyn (%Cdyn) showed significantly lower values in patients with interstitial lung disease (ILD) than in healthy subjects and chronic obstructive pulmonary disease (COPD) patients and significant correlations with vital capacity and lung diffusion capacity.

Comparison of impedance measured by the forced oscillation technique and pulmonary functions, including static lung compliance, in obstructive and interstitial lung disease.

Objective: To examine whether the parameters of impedance measured by the broadband frequency forced oscillation technique (FOT) were reflected by changes in lung compliance induced by emphysema and fibrosis, we retrospectively compared the parameters of FOT and pulmonary functions, including static lung compliance (Cst), in obstructive lung disease (OLD) and interstitial lung disease (ILD). Patients and methods: The data of 18 patients with OLD (16 with COPD, two with asthma COPD overlap), 11 with ILD, and 24 healthy volunteers, whose respiratory impedance was measured using a MostGraph-01 and other pulmonary functions including Cst and lung resistance (RL) were measured on the same day and were retrospectively collected and compared. Results: The parameters of resistance, reactance, and resonant frequency showed good correlations with ventilation unevenness (r=0.63, -0.89, 0.77, respectively) and lung elastic resistance (r=0.59, -0.80, 0.73, respectively) in all groups (N=53). These indices were significant determinants of increased respiratory resistance and more negative shift of respiratory reactance (Xrs) at lower frequency (P<0.001). Decreased functional residual capacity was also a determinant of Xrs at 5 Hz (X5) (P<0.05). The differences in mean X5 in the expiratory phase relative to those in the inspiratory phase (within-breath changes in X5) were associated with airflow obstruction (P<0.002) and lung elastic resistance (P<0.001). However, no significant correlations between Cst and any parameters of respiratory impedance were observed. Conclusions: These findings suggest that the impedance parameters measured by FOT are reflected by airway obstruction, ventilation unevenness, and lung resistance, but hardly reflected by changes in lung compliance due to emphysema or fibrosis in both CLD and ILD.

Instability of nocturnal parasympathetic nerve function in patients with chronic lung disease with or without nocturnal desaturation.

Objective/background: This study was performed to evaluate the association of nocturnal autonomic nerve (AN) dysfunction, especially parasympathetic nerve (PN) function instability, and nocturnal oxygen desaturation (NOD) in patients with chronic lung diseases (CLD). Patients and methods: Twenty-nine stable CLD patients with irreversible pulmonary dysfunction and mild-to-moderate daytime hypoxemia, 13 CLD patients receiving long-term oxygen therapy (LTOT) with maintained SpO2 >90%, and 17 senior healthy volunteers underwent two-night examinations of nocturnal AN function by pulse rate variability (PRV) instead of heart rate variation using a photoelectrical plethysmograph simultaneously monitoring SpO2 and the presence of sleep disordered breathing at home. AN function was examined by instantaneous time-frequency analysis of PRV using a complex demodulation method. Results: There were no significant differences in mean low frequency/high frequency (HF) ratio (index of sympathetic nerve activity) or mean HF amplitude (index of PN activity) among controls and CLD patients with and without NOD (defined as SpO2 <90% for at least 3% of total recording time at night). However, the relative times over which the same main HF peak was sustained for at least 20 seconds (%HF20sec) and 5 minutes in total recording time, indexes of PN function stability, were significantly reduced in CLD patients compared with controls, and further decreased in CLD patients with NOD compared with non-NOD. %HF20sec was significantly higher in the LTOT group than the NOD group. Furthermore, PaO2 at rest and nocturnal hypoxia were significantly correlated with PN function instability in CLD patients. Conclusion: PN function is unstable at night associated with nocturnal hypoxemia in CLD patients, which may reflect poor quality of sleep.

Efficacy of tiotropium and indacaterol monotherapy and their combination on dynamic lung hyperinflation in COPD: a random open-label crossover study.

BACKGROUND AND OBJECTIVE: The difference in efficacy of long-acting muscarinic antagonists (LAMAs) and long-acting ß2-agonists (LABAs) for dynamic lung hyperinflation (DLH) in COPD is unclear. The purpose of this study was to elucidate the difference in efficacy of LAMA and LABA alone and the combination thereof for DLH. SUBJECTS AND METHODS: Thirty stable patients were enrolled and randomly divided into two groups following baseline measurements. One group was treated with 5 µg tiotropium (Respimat inhaler) for 4 weeks following a 4-week treatment with 150 µg indacaterol, while the other group was treated with indacaterol for 4 weeks following a 4-week treatment with tiotropium. For both groups, these treatments were followed by a combination of the two drugs for 4 weeks. Pulmonary function tests, including DLH evaluated by metronome-paced incremental hyperventilation and exercise tolerance evaluated by the shuttle-walk test, were performed at the end of each treatment period. RESULTS: In total, 23 patients completed this study. Both tiotropium and indacaterol alone significantly increased forced expiratory volume in 1 second, exercise tolerance, and improved health status. Tiotropium significantly improved DLH, but indacaterol did not. The combination therapy resulted in further improvements in lung function and exercise tolerance, but not in DLH. CONCLUSION: The efficacy of tiotropium in inhibiting DLH following metronome-paced incremental hyperventilation may be superior to that of 150 µg indacaterol, although the effects on airflow obstruction were the same, and the combination therapy showed further improvement in airflow obstruction, but not in DLH.

[Value of Fractional Exhaled Nitric Oxide after Using a Beta-2 Bronchodilator in the Differential Diagnosis of Bronchial Asthma and Chronic Obstructive Pulmonary Disease].

It has been established that an increase in fractional exhaled nitric oxide (FeNO) is one of the indicators of bronchial asthma (BA) in clinical settings. However, the differential diagnosis of BA and chronic obstructive pulmonary disease (COPD) is difficult due to pathological similarities. Therefore, to determine if FeNO may be utilized in the differential diagnosis of BA and COPD, we compared FeNO values before and after inhalation of a short-acting beta-2 agonist (SABA). There were 3 groups of subjects recruited to this study: (1) 23 normal healthy controls, (2) 36 patients with BA, and (3) 13 patients with COPD. We measured FeNO, forced vital capacity, forced expiratory volume in 1 second (FEV1), and FEV1%, calculated using spirometry. Then, after the subjects inhaled the SABA, we measured these data after 10 and 30 minutes. Here we found that after inhalation of a SABA, 8 cases in the BA group who showed reversibility of airway obstruction demonstrated significantly increased FeNO values compared to the BA patients with non-reversible airway obstruction, those with COPD, and healthy subjects. This finding may be because the obstructed pulmonary peripheral airway was expanded by inhaling a SABA, and nitric oxide, which had been produced in the peripheral airway, was then exhaled. These results suggest the possibility that FeNO may be utilized in the differential diagnosis of BA and COPD.

Clinical features of four cases with cashew nut allergy and cross-reactivity between cashew nut and pistachio.

BACKGROUND: Few cases of cashew nut (CN) allergy have been reported in Japan. We evaluated the clinical features of 4 cases with CN allergy and investigated the allergens involved. METHODS: In order to investigate the cross-reactivity between CN and pistachios, we performed ImmunoCAP inhibition tests using sera of 4 cases with positive histories of CN allergy and positive results of specific IgE measurement (ImmunoCAP) and skin prick tests. Furthermore, we analyzed the molecular weights of allergens of CN and pistachios by IgE-immunoblotting. RESULTS: Of the 4 cases (male : female = 1:3), there were 3 cases (patient #2-4) and 1 case (patient #1) of anaphylaxis and oral allergy syndrome, respectively. The initial symptom was an oropharyngeal symptom in 3 of the 4 cases, of which 2 cases developed anaphylaxis within 10 minutes after eating only a few pieces of CN. All 4 cases reacted positively to the skin prick test with CN, although 1 case of anaphylaxis tested negatively for CN by ImmunoCAP. Additionally, in 2 cases, IgE-binding to CN and pistachio were inhibited with both pistachios and CN, indicating cross-reactivity between CN and pistachios. IgE-immunoblotting of CN using sera from the 4 cases revealed 2 bands at molecular weights of approximately 33 kd and 42 kd, whereas that of pistachios showed a single band at 36 kd. However, IgE in all 4 sera did not bind to rAna o 2. CONCLUSIONS: In CN allergy, a small amount of CN could induce a severe anaphylactic reaction. Moreover, in cases of suspected CN allergy, reactions to not only CN but also pistachio, which could be cross-reactive to CN, should be examined.

[Oral allergy syndrome due to plant-derived foods: a clinical review of 63 patients over a period of 6 years].

BACKGROUND: The clinical features of many patients with oral allergy syndrome (OAS) due to plant-derived foods have rarely been reported in Japan. OBJECTIVES: We aimed to determine the causative foods of OAS due to plant-derived foods based on clinical features and skin prick tests (SPTs). Furthermore, we aimed to elucidate the association between causative foods and sensitized pollens in patients with OAS due to plant-derived foods. METHODS: SPTs and specific IgE measurements (CAP-FEIA: CAP) were performed in relation to foods and pollens in 118 patients with positive histories of OAS due to plant-derived foods. Patients with positive histories and with positive skin test responses were identified as having type I allergy to the causative foods. RESULTS: The mean age of 63 patients with positive histories and positive skin test responses was 29.2 years (range, 2-61 years), and there were twice as many females as male. The most frequent causative foods were found to be apple, peach, kiwi, and melon in 13, 12, 12, and 11 patients, respectively. CAP frequency was shown to be similar to that of SPT regarding apple, whereas it was less than that of SPT regarding melon, peach, and kiwi. A significant correlation between the frequencies of SPT and CAP was found regarding apple (r=0.39, p<0.05) but not peach, kiwi, and melon. Forty-one of 63 patients with OAS (66.1%) had pollinosis and/or allergic rhinitis. In patients with OAS due to apple, the positive ratio of CAP response against alder pollen was higher than that in patients with OAS due to melon. In patients with OAS due to melon, the positive ratio of CAP responses against ragweed pollen, grass pollen, and mugwort pollen was higher than that in patients with OAS due to apple. CONCLUSION: In this study, positive ratios of SPT and CAP tended to differ according to the causative food, showing a smaller potential for reaction than might be suggested by patient history. Therefore, for the time being it would be more accurate to use a skin test for the diagnosis of OAS due to plant-derived foods.