Background: Continuous positive airway pressure (CPAP) is considered as the standard therapy for obstructive sleep apnea syndrome (OSAS), but some patients with OSAS are unable to accept CPAP due to nasal obstruction and poor nasal airflow. Objectives: We assessed the influence of nasal resistance before beginning CPAP treatment on the initial acceptance of CPAP in OSAS patients. Methods: The study subjects comprised 77 patients (74 males, 3 females) with primary OSAS, all of whom received CPAP treatment with nasal masks. Before trials, all subjects underwent overnight polysomnography, and nasal resistance was measured with active anterior rhinomanometry in the seated position on the first day of CPAP trial. Results: The CPAP treatment was accepted by 56 patients after the initial trials with overnight polysomnography. Body mass index, the number of apnea/hypopnea episodes per hour (apnea/hypopnea index; AHI), and the number of episodes per hour with an oxygen desaturation of >3% (oxygen desaturation index) were significantly higher (p < 0.01) and nasal resistance was lower (p = 0.003) in patients who accepted CPAP than in those who did not. Logistic regression analysis, with patient age, body mass index, Epworth sleepiness scale score, AHI, oxygen desaturation index, and nasal resistance before CPAP treatment as explanatory variables, showed that nasal resistance (OR + 0.1 Pa/cm3/s: 1.48; p = 0.002) and AHI (OR + 1 event/h: 0.93; p = 0.003) were significant factors for CPAP non-acceptance. Conclusions: Nasal resistance before the beginning of CPAP treatment has a significant effect on the acceptance of CPAP in OSAS patients, and hence, could be a predictive parameter for the initial acceptance of CPAP.
The pathological changes of Alzheimer's disease include the deposition of amyloid β protein (Aβ) as senile plaques in the brain. We hypothesized that the rapid removal of Aβs from the blood may act as a peripheral Aβ drainage sink from the brain. In this study, the plasma Aβ concentrations and the cognitive functions were investigated for in 57 patients on hemodailysis (69.4 ± 3.8 years), 26 renal-failure patients without hemodialysis (66.6 ± 14.7 years), and 17 age-matched healthy controls (66.6 ± 4.1 years). The concentrations of plasma Aβs increased along with the decline of renal functions. Moreover, the renal-failure patients without hemodialysis and with poorer renal functions showed lower cognitive functions. The plasma concentrations of Aβ(1-42) correlated with serum creatinine (P < 0.001) and Mini-Mental-State Examination scores (P = 0.017). The dialyzers effectively removed Aβs in the blood during hemodialysis sessions. The plasma Aβ concentrations showed steady or slightly decreasing along with duration of hemodialysis. The total amount of Aβs removed during a hemodialysis session was calculated to be comparable to the Aβs dissolved in the blood and the cerebrospinal fluid. The MMSE scores of the hemodialysis patients showed no clear decrease in longer hemodialysis duration. Therefore, the therapeutic approach for Alzheimer's disease by removing Aβs from the blood is worthy of further investigation, including whether or not Aβs in the brain decrease.
To obtain the proof of concept of a novel therapy for Alzheimer's disease (AD), we conducted two prospective studies with hemodialysis patients who had amyloid β protein (Aβ) removed from their blood three times a week. One major pathological change in the brain associated with AD is Aβ deposition, mainly 40 amino acids Aβ1-40 and 42 amino acids Aβ1-42. Impaired Aβ clearance is proposed to be one cause of increased Aβ in the AD brain. Thus, we hypothesized that an extracorporeal removal system of Aβ from the blood may remove brain Aβ and be a useful therapeutic strategy for AD. In the first prospective study, plasma Aβ levels and the cognitive function of 30 hemodialysis patients (65-76 years old) were evaluated at baseline as well as 18 or 36 months after. Although plasma Aβ1-40 levels either decreased or remained unchanged, levels of Aβ1-42 either remained unchanged or increased at the second time point. Mini-Mental State Examination scores of most subjects increased or were maintained at the second time point. Aβ1-40 influx into the blood correlated with MMSE at the second time point. In the second prospective study, five patients (51-84 years old) with renal failure were evaluated before and after the initiation of hemodialysis. Plasma Aβ levels decreased, while cognitive function improved after initiating blood Aβ removal. Therefore, long-term hemodialysis, which effectively removes blood Aβ, might alter Aβ influx and help maintain cognitive function.
There is no relatively hypovascular region in the nerve root that is vulnerable in the course of degenerative changes in the lumbosacral spine. Therefore, it is unlikely that the watershed represents a weak point of the blood flow in the nerve root.
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