Quantitative proteome analysis using D-labeled N-ethylmaleimide and 13C-labeled iodoacetanilide by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A new methodology for quantitative analysis of proteins is described, applying stable-isotope labeling by small organic molecules combined with one- or two-dimensional electrophoresis and MALDI-TOF-MS, also allowing concurrent protein identification by peptide mass fingerprinting. Our method eliminates fundamental problems in other existing isotope-tagging methods requiring liquid chromatography and MS/MS, such as isotope effects, fragmentation, and solubility. It is also anticipated to be more practical and accessible than those LC-dependent methods.

[Epidemiological study of snoring--a questionnaire survey in factory workers]

There has been no epidemiological study of snoring in Japan, and we therefore performed a questionnaire survey (in about 7,000 adult men working at a steel-making factory at the time of the yearly health examination, and investigated the relationship between the severity of snoring and 17 items including age, obesity, family history of snoring, daytime hypersomnolence, hypertension, smoking, alcohol intake and traffic accidents. We classified all the subjects into three groups, no snoring, mild snoring, and severe snoring group. We defined severe snorers as persons who snored loudly in both inspiratory and expiratory phases and those who snored loudly with apnea. We found that aging, obesity, smoking and alcohol intake are risk factors for snoring. Compared with non-snorers, severe snorers were found to have a high incidence of family history of snoring, daytime hypersomnolence, and history of treatment of hypertension. No relationship was found between the severity of snoring and the occurrence of automobile accidents. The proportion of severe snorers over 40 years old with obesity, daytime hypersomnolence and morning headache was 0.25%, representing the group that may have obstructive sleep apnea syndrome. The probable incidence of sleep apnea syndrome in men may be considerably lower in Japan compared with that in either U.S.A. or Europe.

S-100-immunoreactive giant macrophages in lymphoid tissues of the guinea pig

Giant cells containing S-100 protein of the lymphoid tissues in the guinea pig were studied by immunohistochemistry using S-100 antiserum. S-100-immunoreactive giant cells were dendritic in shape, contained one or two irregular-shaped, euchromatic nuclei, phagosomes of various diameter, numerous mitochondria and microfilaments in the perikaryon, and extended cell processes free of cell organelles. These cells predominantly lined the superficial cortex facing the subcapsular sinus, were less numerously scattered in the medulla of lymph nodes and located at the marginal zone of the spleen. They also stained with S-100 alpha monoclonal antiserum and showed active phagocytosis for aldehyde-fixed red cells or colloidal carbon in the popliteal lymph node and spleen. S-100-immunoreactive giant cells also appeared in the corticomedullary zone of the thymus and in the interfollicular area of the Peyer's patches of the gut. Small sinus macrophages, which exhibited active phagocytosis for colloidal carbon but were less active for red cells in the popliteal lymph node and spleen, were not stained with S-100 antiserum. These findings indicate that S-100-immunoreactive giant cells of the lymph node and spleen are a subpopulation of macrophages different from S-100-negative cells of the small type.

[A case of obstructive sleep apnea syndrome remarkably improved by gastric restriction surgery]

A 23-year-man with morbid obesity and obstructive sleep apnea syndrome (OSAS) was admitted. He was 170 cm in height and 170 kg in weight. He underwent dietary treatment several times, but his weight returned to its original level, or even higher, within a short period. A diagnosis of OSAS was made by nocturnal polysomnography. In this morbidly obese patient with OSAS a nocturnal sleep apnea study was performed before and after weight reduction surgery (gastric restriction). The postoperative findings revealed a dramatic body weight reduction. At the same time, the results of apnea and oxygen desaturation were remarkably improved too. These results indicate that weight reduction surgery is a definitely effective treatment for morbid obesity associated with OSAS.

[Indications for home oxygen therapy in cases of sleep oxygen desaturation]

Home oxygen therapy is now considered indicated in cases of severe sleep oxygen desaturation. To explore whether we could choose cases with severe sleep desaturation by measurement of waking physiological parameters, we examined the relationship between arterial blood gases, lung functions and pulmonary artery pressure while awake and the degree of sleep oxygen desaturation in 21 patients with chronic obstructive pulmonary disease and 22 cases with a past history of pulmonary tuberculosis. There were significant correlations between waking PaO2, PaCO2 and pulmonary artery mean pressure and sleep lowest SaO2, respectively, whereas no significant relation was found between %VC or FEV1.0% and sleep lowest SaO2. However, we found wide ranges of PaO2 and PaCO2 in cases who had 10 min or more with SaO2 below 85% during sleep. This was also true in the patients who underwent 60 min or more with SaO2 below 85% while a sleep. These results suggest that it may be difficult to find out the indications for cases with severe sleep desaturation by evaluation of arterial blood gases while awake.

[Prediction of the degree of nocturnal oxygen desaturation in sleep apnea syndrome by estimating the testosterone level]

We studied the influence of hypoxia due to sleep apnea on testosterone (T) secretion. It was conducted on the basis of an idea that sustained hypoxia may depress T secretion. The subjects consisted of 15 male patients with no drug administration whose complaints were snoring and/or obesity. The subjects participated in a sleep study on two consecutive nights. During the first night we collected blood samples starting every 4 hours from 10 PM via a catheter and measured T. From the data of the second night, we calculated total desaturation time with more than 4% from the baseline SaO2. According to the amount of this desaturation time, the subjects were divided into 2 groups; desaturation time less than 80 min in group 1 and longer in group 2, respectively. The peak value was seen at 6 AM in group 1 and at 10 AM in group 2. We investigated the correlation between the ratio of T10/T6, which is the ratio of T level at 10 AM to that at 6 AM, and parameters of sleep disorders related to oxygen desaturation. Total 4% desaturation time in total sleep period and non REM period significantly correlated with this ratio. From the diagram illustrating the correlation between the ratio and total 4% desaturation time in total sleep period, we could assume that if the ratio is beyond 1, the subject may have had more than about 80 min of total 4% desaturation time.