Mitsushi Okazawa

Functional Changes in Aging Polymorphonuclear Leukocytes

BACKGROUND Previous studies from our laboratory have shown that the expression of L-selectin on polymorphonuclear neutrophils (PMN) decreases as the cell ages in the circulation and that these older PMN have more fragmented DNA and show morphological features of apoptosis. METHODS AND RESULTS The present study was designed to compare the functional capabilities of PMN expressing low levels of L-selectin (L-selectin[low]) and the total population of PMN they were isolated from (L-selectin[mixed]). The results show no difference of the baseline filamentous actin (F-actin) content between PMN expressing low and high levels of L-selectin. However, the ability of L-selectin(low) PMN to assemble F-actin was impaired after stimulation by n-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) (1 nmol/L fMLP: P<.02, 10 nmol/L fMLP: P<.01). The ability of L-selectin(low) PMN to change shape when stimulated (10 nmol/L fMLP) was also decreased (P<.05). Filtration studies showed no difference in baseline deformability between L-selectin(low) and L-selectin(mixed) leukocytes, but the L-selectin(low) cells showed a decreased ability to stiffen after fMLP stimulation (P<.05). L-selectin(low) cells demonstrated a decreased ability to migrate toward a chemoattractant (1, 3, and 10 nmol/L fMLP) (P<.004) but have an enhanced ability to upregulate CD18 (P<.00002) and produce hydrogen peroxide (P<.00004). CONCLUSIONS We conclude that PMN undergo substantial functional changes as they age in the circulation.

Fast Fourier transform analysis of dynamic data: sine wave stress - strain analysis of biological tissue

We propose an improvement to the dynamic oscillation method using as an example the measurement of the tensile stiffness of the rabbit tracheal mucosal membrane. A sine wave oscillation technique was used to study the tissue mechanical properties. A mathematical model was developed using fast Fourier analysis. After mathematically eliminating the machine response, this analysis reveals the tissue frequency response over a wide range of frequencies. This study addresses the advantages of using Fourier analysis to interpret dynamic properties of biological tissue and provides a complete description of how to obtain the pure tissue response.

Gender Differences in the Clinical Features of Sleep Apnea Syndrome

Objective Sleep apnea syndrome is more prevalent among men than women and is frequently accompanied by metabolic syndrome (MetS). However, gender differences in the effect of sleep-disordered breathing (SDB) leading to the risk of MetS remain unclear. The aim of our study was to investigate the clinical characteristics of SDB in women and the differential influence of SDB on MetS between genders. Methods In a single-center retrospective study, we compared the data of 1,809 consecutive SDB patients by gender to clarify the characteristics of sleep disorders in women. We also compared the prevalence of MetS and its related abnormalities by gender. A logistic regression analysis was used to determine the contributory factors for MetS. Results The mean age and proportion of patients over 50 years of age were higher in women than in men. SDB was milder in women than in men according to polysomnography findings. Elevated Hemoglobin A1c levels and hyperlipidemia were less frequent in women than in men. The MetS prevalence was similar in women and men (30.0% vs. 35.2%). A logistic regression analysis showed that the apnea-hypopnea index (AHI) was an independent risk factor for MetS in both genders, but that female gender was independently associated with a decreased prevalence of MetS and its related abnormalities. Conclusion Female SDB patients tend to be older with milder apnea and sleepiness than male SDB patients. A higher AHI is a significant risk factor for MetS in both genders, although female gender is an independent inhibitory factor for developing MetS in SDB patients.

Increased airway hyperresponsiveness to adenosine in patients with aspirin intolerant asthma

Age (mean ± SD) 42.6 ± 17.0 42.1 ± 14.9 n.s. Male 4 5 n.s. Atopy (þ/ ) 6/3 12/6 n.s. Severity (mild/moderate) 5/7 7/10 n.s. FVC (ml, mean ± SD) 3006 ± 586 3085 ± 722 n.s. FEV1.0 (ml, mean ± SD) 2430 ± 537 2365 ± 602 n.s. FEV1.0% (%, mean ± SD) 81.4 ± 9.2 77.2 ± 6.8 n.s. %FEV1.0 (%, mean ± SD) 90.3 ± 14.3 85.5 ± 13.3 n.s. WBC (/ml, mean ± SD) 6300 ± 1500 6900 ± 2200 n.s. Eosinophil (%, mean ± SD) 9.2 ± 6.3 6.5 ± 2.9 n.s. IgE (U/ml, mean ± SD) 285.5 ± 272.4 421.3 ± 404.9 n.s. Therapy n.s. ICS (mg, mean ± SD) 420 ± 261 360 ± 214 n.s. LABA (n) 6 5 n.s. Theophylline (n) 9 13 n.s. Dear Editor,