Elevated nocturnal and morning blood pressure in patients with obstructive sleep apnea syndrome / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The nocturnal nondipping and elevated morning blood pressure (BP) in patients with obstructive sleep apnea syndrome (OSAS) have not yet been well investigated in Chinese patients. This study aimed to describe the BP profile, and to elucidate the relationships between daytime BP and nighttime BP, and between evening BP and morning BP in patients with OSAS.</p><p><b>METHODS</b>Twenty teaching hospital sleep centers in China were organized by the Chinese Medical Association to participate in this study and 2297 patients were recruited between January 2004 and April 2006. BP assessments were made at four time points (daytime, evening, nighttime and morning) and polysomnography (PSG) was performed and subjects were classified into four groups by their apnea-hypopnea index (AHI): control, n = 213 with AHI < 5; mild, n = 420 with AHI ≥ 5 and < 15; moderate, n = 460 with AHI ≥ 15 and < 30; and severe, n = 1204 with AHI ≥ 30. SPSS 11.5 software package was used for statistical analysis and figure drawing.</p><p><b>RESULTS</b>All the average daytime, nighttime, evening and morning BPs were positively correlated with AHI and negatively correlated with nadir nocturnal oxygen saturation. The ratios of nighttime/daytime and morning/evening average BP were positively correlated with AHI. The ratio of nighttime/daytime systolic BP became a "reversed BP dipping" pattern until the classification reached severe, while the ratio of nighttime/daytime diastolic BP became reversed at moderate. Similarly, the ratio of morning/evening diastolic BP becomes reversed even at mild.</p><p><b>CONCLUSIONS</b>OSAS may result in higher BP levels at all four time points. The ratios of nighttime/daytime and morning/evening BP increase with increased AHI. The increasing of diastolic BP, which is inclined to rise more quickly, is not parallel with increasing systolic BP.</p>

Chronic intermittent hypoxia aggravates cardiomyocyte apoptosis in rat ovariectomized model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The prevalence of obstructive sleep apnea (OSA) increases after menopause in women, but remains under diagnosed because of social or lifestyle factors. It is important to evaluate the hazards of OSA on cardiovascular disease in menopausal women. We tested the hypothesis that chronic intermittent hypoxia (CIH) may aggravate cardiomyocyte apoptosis in ovariectomized (OVX) Sprague Dawley (SD) rats; the changes of anti-oxidation ability in cardiac muscles may be one of the reasons for cardiomyocyte apoptosis.</p><p><b>METHODS</b>Forty-eight 60-day old female SD rats were randomly divided into a CIH group, OVX group, OVX+CIH (OC) group, and handled control (HC) group, and the rats were exposed either to CIH (nadir O2 6%) or handled normoxic controls. The changes of body weight and whole heart weight were measured. Super oxide dismutase (SOD) and malonaldehyde (MDA) were used to evaluate the level of oxidative stress. TdT-mediated dUTP nick end labeling (TUNEL) was used to measure apoptosis in each rat. Western blotting was used to measure apoptosis associated proteins in cardiac muscle samples from each rat.</p><p><b>RESULTS</b>When compared with the HC and CIH groups, the levels of oxidative stress in the OC and OVX groups were significantly higher. The levels of SOD in the HC, CIH, OC, and OVX groups were (47.99 ± 4.89), (53.60 ± 4.47), (20.99 ± 2.72), and (30.64 ± 3.79) mmol/mg protein; significantly increased in the CIH group (P < 0.05) and significantly decreased in the OC (P < 0.01) and OVX (P < 0.05) groups. The levels of MDA in the HC, CIH, OVX, and OC groups were (1.63 ± 0.20), (1.93 ± 0.77), (3.30 ± 0.39), and (1.95 ± 0.20) mmol/mg protein; it significantly increased in the CIH (P < 0.05), OC (P < 0.01), and OVX (P < 0.05) groups compared with the HC group. Bax protein expression was significantly increased and bcl-2 protein expression was significantly reduced after CIH compared with HC rats (P < 0.05). The protein expression of bax and bcl-2 in the OC group was not significantly different from the CIH group, but the ratio of bax/bcl-2 was significantly increased in the OC group (P < 0.05); this was associated with severe cardiomycyte apoptosis in the OC group. TUNEL confirmed this observation.</p><p><b>CONCLUSIONS</b>This study found that CIH may induce oxidative stress in OVX rats but not in CIH rats, and cause more severe cardiomyocyte apoptosis in OVX rats compared with CIH rats. This means that OVX rats exposed to CIH suffered more severe cardiac injury compared with CIH rats due to reduced antioxidation. These findings may partly explain the reason why OSA has a worse cardiovascular impact on menopausal women, and emphasize the importance of detection and early treatment of OSA in menopausal patients.</p>

Relationship of daytime blood pressure and severity of obstructive sleep apnea among Chinese: a multi-center investigation in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Epidemiologic studies have shown an independent and definite association between obstructive sleep apnea (OSA) and hypertension. This study aimed to define the association between daytime blood pressure and severity of OSA in Chinese population in mainland of China.</p><p><b>METHODS</b>Twenty university hospital sleep centers in mainland of China were invited by the Chinese Medical Association (CMA) to participate in this epidemiologic study and 2297 consecutive patients (aged 18 - 85 years; 1981 males and 316 females) referred to these twenty sleep centers for evaluation of OSA between January 2004 and April 2006 were prospectively enrolled. Nocturnal polysomnography was performed in each patient, and disease severity was assessed based on the apneahypopnea index (AHI). These patients were classfied into four groups: nonapneic control (control, n = 257) with AHI < or = 5 episodes/hour; mild sleep apnea (mild, n = 402) with AHI > 5 and < or = 15 episodes/hour; moderate sleep apnea (moderate, n = 460) with AHI > 15 and < or = 30 episodes/hour and severe sleep apnea (severe, n = 1178) with AHI > 30 episodes/hour. Daytime blood pressure measurements were performed under standardized conditions in each patient at 10 a.m. in office on the day of referring to sleep centers for getting average value. All the patients were requested to quit medications related to blood pressure for three days before the day of assessing.</p><p><b>RESULTS</b>Both daytime systolic blood pressure and diastolic blood pressure values were significantly related to AHI positively (r = 0.201 and 0.276, respectively; both P values < 0.001) and to nadir nocturnal oxygen saturation negatively (r = -0.215 and -0.277, respectively; both P values < 0.001), which were the parameters of OSA severity. In two special designed mean plots, means of daytime systolic and diastolic blood pressure increased gradually with increasing AHI. Beyond AHI of 61 - 65, this increasing trend reached a plateau.</p><p><b>CONCLUSIONS</b>The results showed that OSA severity was associated with daytime blood pressure until AHI of 61 - 65, providing evidence for early OSA management, especially in OSA patients with concomitant hypertension.</p>

Chronic intermittent hypoxia from pedo-stage decreases glucose transporter 4 expression in adipose tissue and causes insulin resistance / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The persistence of sleep disordered breathing (SDB) symptoms after tonsil and/or adenoid (T&A) surgery are common in children with obstructive sleep apnea (OSA). We tested the hypothesis that disturbances of glucose transporters (GLUTs) in intraabdominal adipose tissue caused by chronic intermittent hypoxia (CIH) from the pedo-period could facilitate the appearance of periphery insulin resistance in Sprague-Dawley (SD) rats. We tested the hypothesis that the changes of GLUTs in adipose tissue may be one of the reasons for persistent SDB among clinical OSA children after T&A surgery.</p><p><b>METHODS</b>Thirty 21-day-old SD rats were randomly divided into a CIH group, a chronic continuous hypoxia (CCH) group, and a normal oxygen group (control group) and exposed for 40 days. The changes of weight, fasting blood glucose and fasting blood insulin levels were measured. Hyperinsulinemic-euglycemic clamp techniques were used to measure insulin resistance in each animal. Real-time quantitative PCR and Western blotting were used to measure GLUT mRNA and proteins in intraabdominal adipose tissue. Additional intraabdomial white adipose tissue (WAT) was also processed into paraffin sections and directly observed for GLUTs1-4 expression.</p><p><b>RESULTS</b>When compared with control group, CIH increased blood fasting insulin levels, (245.07 +/- 53.89) pg/ml vs. (168.63 +/- 38.70) pg/ml, P = 0.038, and decreased the mean glucose infusion rate (GIR), (7.25 +/- 1.29) mg x kg(-1) x min(-1) vs. (13.34 +/- 1.54) mg x kg(-1) x min(-1), P < 0.001. GLUT-4 mRNA and protein expression was significantly reduced after CIH compared with CCH or normal oxygen rats, 0.002 +/- 0.002 vs. 0.039 +/- 0.009, P < 0.001; 0.642 +/- 0.073 vs. 1.000 +/- 0.103, P = 0.035.</p><p><b>CONCLUSIONS</b>CIH in young rats could induce insulin resistance via adverse effects on glycometabolism. These findings emphasize the importance of early detection and treatment of insulin insensitivity in obese childhood OSA.</p>

Epidemiologic study on the relationship between smoking and sleep apnea/hypopnea syndrome / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate how smoking was affecting the prevalence of sleep apnea/ hypopnea syndrome (SAHS) among adults aged over 30 years in Chengde city of Hebei province.</p><p><b>METHODS</b>1168 subjects, over 30 years of age were derived from a random sample from a community-based population in Shuangqiao district of Chengde city. All subjects responded to a questionnaire at their own houses regarding their habits of snoring and smoking. 1168 subjects (95.2%) answered the questions satisfactorily.</p><p><b>RESULTS</b>(1) Among the smoking groups, the prevalence of snoring was 69.09%, higher than that in the nonsmoking groups 45.07% (P = 0.000). (2) In males, the smoking group had a higher prevalence (69.72%) of snoring than in the nonsmoking group (60.80%, P = 0.033). (3) Females in the smoking group had a higher prevalence of snoring (61.80%) than in the nonsmoking group (39.70%, P = 0.011). (4) The prevalence of snoring in males (60.80%) was significantly higher than that in females (39.70%, P = 0.000). (5) The prevalence (69.72%) of snoring in smoking males was similar to that in smoking females (61.80%, P = 0.336). (6) Data from logistic regression analysis indicated that smoking was one of the factors affecting snoring. (7) According to the degree of snoring, 127 moderate and severe snorers were measured by portable PSG for a whole night and the prevalence of SAHS was estimated. According to the AHI > or = 5 and the ESS > or = 9 cutoff-points, the prevalence rates of SAHS in smoking groups were both significantly higher than that in nonsmoking groups (P < 0.001).</p><p><b>CONCLUSION</b>Smoking and snoring among adults aged over 30 years had correlation in our city.</p>

Validity of Asthma Control Test in Chinese patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>So far, in China, there has been no effective or easy procedure to define the control of asthma. This study assesses the validity of Asthma Control Test in Chinese patients.</p><p><b>METHODS</b>Three questionnaires (Asthma Control Test, Asthma Control Questionnaire and the 30 second asthma test) were administered to 305 asthma patients from 10 teaching hospitals across China. Spirometry was also used. Asthma specialists rated the control of asthma according to patients' symptoms, medications and forced expiratory volume in first second. The patients were divided into noncontrolled group and controlled group according to the specialists' rating. Reliability, empirical validity and screening accuracy were conducted for Asthma Control Test scores. Screening accuracy was compared among 3 questionnaires. The patients' self rating and the specialists' rating were also compared.</p><p><b>RESULTS</b>The internal consistency reliability of the 5-item Asthma Control Test was 0.854. The correlation coefficient between Asthma Control Test and the specialists' rating was 0.729, which was higher than other instruments. Asthma Control Test scores discriminated between groups of patients differing in the percent predicted forced expiratory volume in first second (F = 26.06, P < 0.0001), the specialists' rating of asthma control (F = 88.24, P < 0.0001) and the Asthma Control Questionnaire scores (F = 250.57, P < 0.0001). Asthma Control Test showed no significant difference with Asthma Control Questionnaire in the percent correctly classified, while the percent correctly classified by Asthma Control Test was much higher than 30 second asthma test. The patients' self rating was the same as assessment of the specialists (t = 0.65, P = 0.516).</p><p><b>CONCLUSION</b>The Asthma Control Test is an effective and practicable method for assessing asthma control in China.</p>

An analysis for 23 cases of Marfan syndrome complicated with thoracic, pulmonary and diaphragmatic diseases / 中华全科医师杂志

0.05),including seven with spinal kyphosis,seven with thoracic deformity,five with pleural effusion,five with emphysema diagnosed by chest X-ray film,three with spontaneous pneumothorax,two with diaphragmatic hernia,and one developed severe respiratory failure and the other developed cot pulmonale.Conclusions The thorax,lungs and diaphragm were more easily involved in the patients with Marfan syndrome,and pulmonary specialists should keep an eye on them.

Study on matrix metalloproteinase 1, 9, 12 polymorphisms and susceptibility to chronic obstructive pulmonary disease among Han nationality in northern China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the association between the functional polymorphism of matrix metalloproteinases (MMPs) and the development of chronic obstructive pulmonary disease (COPD).</p><p><b>METHODS</b>147 COPD patients and 120 healthy smoking controls were selected. Spirometry and chest X-rays had been taken. Questionnaires including sex, age, smoking history, occupational exposure were completed. MMP-9 (-1562 C/T), MMP-1(-1607 1G/2G), MMP-12 (-82 A/G), MMP-12(-357 Asn/ Ser) alleles were determined using PCR-RFLP method. Independent samples T test analysis was carried out to compare patients' age, smoking index, FEV1 /FVC, FEV1 % pred with that of healthy controlled group. The frequencies of genotypes and alleles between groups were analyzed by chi-square tests and multilogistic regression.</p><p><b>RESULTS</b>MMP12 Asn/Asn, CT/AsnAsn were risk factors for smoking-induced COPD. The ORs were 2.361 (95% CI: 1.369-4.017) and 2.433(95% CI: 1.159-5.342) respectively while CC/1G1G/ SerSer seemed to be a protective factor for smoking-induced COPD, with OR as 0.457 and 95% CI as 0.231-0.911.</p><p><b>CONCLUSION</b>Asn/Asn, CT/AsnAsn might be susceptible genotypes while CC/GG/SerSer might serve as protective genotype.</p>

Influence of different sleep stages on respiratory regulation in normal humans / 中国医学科学院学报

<p><b>OBJECTIVE</b>To understand the influence of different sleep stages on respiratory regulation in normal people.</p><p><b>METHODS</b>We measured ventilation (VE) and occlusion pressure (P0.1) responses to hyperoxia hypercapnia (deltaVE/deltaPaCO2, deltaP0.1/deltaPaCO2) and isocapnic hypoxia (deltaVE/deltaSaO2 and deltaP0.1/deltaSaO2) in eleven non-snoring healthy people during wakefulness and during non-rapid eye movement (NREM) I + II, NREM III+IV, and rapid eye movement (REM) sleep stages.</p><p><b>RESULTS</b>During NREM I + II and NREM III+IV, the normal subjects showed no significant decrease in P0.1, deltaP0.1/deltaSaO2 and deltaP0.1/deltaPaCO2 (P > 0.05), but deltaVE/ deltaSaO2 and deltaVE/ deltaPaCO2 decreased significantly (P < 0.05). During REM sleep, P0.1 maintained the level during wakefulness, but both hypoxic and hypercapnic responses decreased significantly (P < 0.05).</p><p><b>CONCLUSIONS</b>Sleep has significant influence on respiratory regulation in normal people. The respiratory drive (P0.1) in both NREM and REM sleep stages could maintain the awake level due to an effective compensation to the increase of upper airway resistance. The P0.1 responses to both hypoxia and hypercapnia decrease only in REM sleep stage, which is in consistent with the clinical phenomenon that sleep disordered breathing occurs in REM in normal people.</p>