Mechanism of action and therapeutic indication of prosthetic mandibular advancement in obstructive sleep apnea syndrome

Abstract Prosthetic mandibular advancement (PMA) was applied to nine patients with obstructive sleep apnea syndrome (OSAS) and its therapeutic usefulness, mechanism of action, and clinical indication were discussed based on polysomnographic findings and serial examination of upper airway before and during PMA treatment. Apnea hypopnea index significantly decreased during PMA treatment compared with the value before treatment ( P < 0.01) and the rate of the treatment responder counted 78.1%. Cephalometric variables indicated forward and inferior advancement of mandible in our subjects. Magnetic resonance imaging of the upper airway during sleep revealed a marked improvement of velopharyngeal obstruction in most subjects. In addition, intraesophageal negative pressure during sleep decreased significantly. Our results confirmed the high therapeutic efficacy of PMA for OSAS and indicated forward advancement of the mandible and decrease of negative pressure loading on upper airway with PMA might suppress velopharyngeal collapse. Thus, PMA was regarded as one of the treatments of choice for OSAS occurring based on with velopharyngeal narrowing.     

Nitrogen dioxide production in a nitric oxide inhalation system using the Servo Ventilator 900C

During nitric oxide (NO) inhalation therapy, toxicity may be produced by the reactive metabolite nitrogen dioxide (NO₂). The purpose of the present study was to determine the NO₂ concentration in a NO inhalation system used for respiratory failure in children at relatively low concentrations of NO (< 20 ppm). The production of NO₂ in the NO inhalation system using the Servo Ventilator 900C connected to the test lung under each of 30 combinations of NO concentrations (0, 4, 8, 12, 16, and 19 ppm) and inspired oxygen (O₂) concentrations (21, 40, 60, 80, and 100%). Pressure controlled ventilation was used with a respiratory rate of 20 breaths/min. NO and NO₂ measurements were obtained on the inspiratory side of the Y-piece connected to the test lung. At a given NO level, increases in the concentration of inspired O₂ resulted in increases in the concentration of NO₂ produced, as did increases in the amount of NO at a given concentration of O₂. The mean NO₂ concentration at the inspiratory site of the Y-piece did not exceed 0.05 ppm (the limit of NO₂ as an outdoor air pollutant in the United States) when the NO concentration did not exceed 8 ppm, regardless of the O₂ concentration. NO inhalation therapy for children with severe respiratory failure using the Servo Ventilator 900C can be performed safely when the concentration of NO does not exceed 8 ppm.     

Resistance to activated protein C activity of an anti-/2 -glycoprotein I antibody in the presence of β-glycoprotein I

Some researchers claim that lupus anticoagulant-positive plasma may cause a false-positive reaction in the test for activated protein C (APC) resistance, a hereditary thrombophilic state characterized by abnormal factor V, which frequently causes venous thrombosis, We investigated whether anti-/3₂ -glycoprotein I antibody (aGPI), which has recently come to be regarded as an anti-cardiolipin antibody (aCL) itself, might have an effect on the APC resistance test.     

Arrhythmias in Centenarians

Background: Many studies have shown an increase in the prevalence of arrhythmias with advancing age. However, little is known about arrhythmias in centenarians. Method and Results: Thirty-two Japanese centenarians aged 100–106 years (14 males, 18 females) were studied. All of them had 12-lead EGGs, and 22 also had 24-hour ambulatory monitoring. As controls, 89 healthy Japanese elderly from the same geographic area underwent 12-lead ECG. Their mean age was 75 ± 6 years with a range of 63–93 years, and there were 28 males and 61 females. Twenty-three of them also had Holter ECGs. On the 12-lead ECG, the heart rate was slightly, but significantly, higher in the centenarians (76.8 ± 12.7 beats/min) than that in the elderly subjects (74.9 ± 5.9 beats/min, P < 0.005). PQ and QT_C were significantly longer in the centenarians (174 ± 29 and 439 ± 33 msec, respectively) compared with the elderly subjects (158 ± 23 and 417 ± 31 msec, P < 0.005 and P < 0.001, respectively). Supraventricular premature beats (SVPBs) were observed in 31% of the centenarians and in 4% of the elderly subjects (P < 0.001). First- and second-degree AV block was recorded in 25% of the centenarians and 1% of the elderly subjects (P < 0.001). Right bundle branch block was found in 19% of the centenarians and 7% of the elderly subjects (P < 0.05). There were no differences in the frequency of ventricular premature beats (VPBs) or QRS voltage. On the Holter ECG, there were no significant differences in average heart rate, maximum heart rate, minimum heart rate, or the longest RR interval. A subgroup of centenarians had frequent SVPBs. However, none of them had > 1,000 VPBs/day as opposed to four elderly subjects (P < 0.01). Atrial fibrillation was not observed in any records of the centenarians despite the presence of frequent SVPBs. Conclusion: These data suggest that conduction disturbances of the AV nodal—His-Purkinje system and frequent SVPBs are common in centenarians, whereas very frequent VPBs and atrial fibrillation seem less common.     

Neural substrates of emotional habituation: A PET study using film stimuli

Abstract  While external stimuli are given repeatedly, the level of emotional response gradually decreases. This study aims to reveal the neural substrates of such emotional habituation. Fifteen healthy male volunteers were examined using [¹⁵O]-H₂O-PET scanning. Subjects were required to watch two film clips, a horror scene (emotional task) and a calm scene (non-emotional task). Each film clip was repeatedly presented six times during 12 PET scans. The regional cerebral blood flow (rCBF) in the first two scans of each task was compared with that in the last two scans. On the emotional task, the right retrosplenial cortex (Brodmann's areas 30 and 23) was activated during the former scans, and the bilateral occipital cortices (BA19 and 37) were activated during the latter scans. As for the non-emotional task, the bilateral occipital cortices (BA19 and 37) were activated during the first two scans, and the bilateral prefrontal cortices (BA10) were activated during the last two scans. The activated cerebral region by emotional experience reciprocally transferred from the paralimbic region (the retrosplenial cortex) to the neocortical region (the bilateral occipital cortices) as the experience was repeated. This finding is consistent with the theory that the process of emotional habituation is promoted by the process of conceptualization.     

Risk factors for SIDS in Japan: A record-linkage study based on vital statistics

This study examines the effect of items as reported on birth certificates on sudden infant death. We linked infant death certificates with birth certificates for the infants born in 1989 to residents of the Tohoku, Tokai and Kyushu regions in Japan (n = 409 679), that is, about one-third of the infants born in Japan that year. The mortality rate from sudden infant death, including 88 deaths from sudden infant death syndrome (SIDS) and 17 deaths from instantaneous death, was 25.6 per 100 000 live births. Elevated risk of sudden infant death was associated with low birthweight, late birth order, illegitimacy, male gender and young maternal age. These results correspond to previous studies from Western countries, suggesting a similar pattern for SIDS in Japan.     

A case of bacterial meningitis complicated by posttraumatic cerebrospinal fluid rhinorrhea

This paper reports an 11 year old boy with bacterial meningitis accompanied by post-traumatic cerebrospinal fluid (CSF) rhinorrhea. Streptococcus pneumoniae was cultured from CSF. The clinical course was very rapid before admission and his age relatively high for usual bacterial meningitis. Consequently, we examined the cause in detail. Immunological findings were within normal limits. Although routine graphic examinations, such as cranial X-ray photography, horizontal cranial computed tomography (CT) and magnetic resonance imaging, could not demonstrate a bone defect, both coronal thin-section cranial CT scanning and radioactive isotope counting by means of cotton packed into the nasal cavity were useful for detecting CSF rhinorrhea. In a case of atypical meningitis, the past history should be examined with caution and coronal thin-section CT should be performed.