Measurement of airway resistance in anesthetized and paralyzed subjects: Proposal for evaluation of K1 values

The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflatoins decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K₁ + K₂X. K₁, calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K₂ value of the endotracheal tube used in this study (Portex^® I.D. 8mm, length 26cm) was quite high (5.0cmH₂O·1^–2·sec²), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K₁ measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.(Sakai T, Yoshida H, Yano H et al.: Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K₁ values. J Anesth 2: 139–145, 1988)     

基于贝叶斯多变量联合模型的体检人群脑卒中发病风险因素的纵向研究

背景 脑卒中是目前影响人类健康的主要公共卫生问题之一;健康体检纵向数据累积了大量的健康信息,由于缺失数据多、样本量小等诸多问题,导致其利用率低、重要信息未能得到充分挖掘,进而对常见慢性病的有效防控等工作带来一定困难。目的 基于贝叶斯多变量联合模型,探讨体检人群脑卒中发病风险因素,为慢性病风险因素分析提供新的方法。方法 本研究使用空军军医大学西京医院健康医学中心2008—2015年的体检资料。随访情况：以首次发生脑卒中为结局事件,发生结局事件立即停止随访;若未发生,到2015年体检信息收集完成后结束随访;体检间隔时间为1年。依据随访过程中是否发生脑卒中分为脑卒中组和非脑卒中组。纵向观察变量包括总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）、体质指数（BMI）和收缩压（SBP）。采用多因素Cox回归模型分析基线情况对脑卒中结局事件的影响;采用贝叶斯多变量联合模型,分析随访过程中TC、TG、LDL-C、HDL-C、BMI和SBP的纵向变化轨迹对脑卒中发病的影响。结果 本研究共纳入234例研究对象,1 581条纵向随访记录,平均随访时间为...     

The inheritance of microstructure variation in the song of four generations of Roller canaries

The microstructure of the calls and songs of four generations of Roller canaries was analyzed and compared. Many of the characteristics of the internal structure of the syllable show distributions in the progeny that suggest quantitative inheritance. The presence or absence of an underharmonic and the presence of a block underharmonic show a qualitative type of inheritance.     

Blood volume and right heart haemodynamics in abrupt hypotension following sublingual isosorbide dinitrate in acute myocardial infarction

Arterial blood pressure and heart rate were measured in 43 patientswith acute myocardial infarction and a systolic blood pressure120 mmHg during sublingual administration of 5 mg of isosorbidedinitrate. In 25 of them right heart haemodynamics were alsomeasured. Severe (25%) hypotension developed in 12 patients(Group 1, systolic blood pressure 158 ± 28 to 78 ±17 mmHg, mean ± SD) but not in the remaining 31 (Group2) and was accompanied by a fall in heart rate (82 ±20 to 70 ± 22beats min^-1, P<0.05), in cardiac output(4.3 ± 0.3 to 3.2 ± 0.4l mm^-1, P<0.02, n =5) and in systemic vascular resistances (2326 ± 463 to1532 ± 442 dynes sec^-1 cm^-5, P<0.02) not present inGroup 2. The reduction in right (Group 1,8 ± 3 to 3 ±1, vs. Group 2,10 ± 3 to 6± 3 mmHg, V <0.005)and in left ventricular filling pressures (Group 1,15 ±4 to 8 ± 2, vs. Group 2,18 ± 6 to 13 ±5 mmHg, P<0.001) was more remarkable in Group 1. In thisgroup there was also a high incidence of anterior infarction(9/12, 75%). Blood volume measured in 30 patients was lowerin Group 1 but differences were not significant. A second doseof 5 mg of isosorbide dinitrate 36–48 h later producedneither symptomatic hypotension (Group 1, 147 ± 29 to129 ± 24 mmHg) nor a fall in cardiac output in any patient,whereas changes infilling pressures were comparable to thoseof the first dose. Thus, severe isosorbide dinitrate-induced hypotension in myocardialinfarction is limited to the acute phase and seems more prevalentin anterior infarction but can not be clearly predicted fromresting haemodynamic or blood volume measurements, at leastin non-hypotensive patients. Moreover, it appears to be causedby an excessive ventricular emptying due to a striking venousand arterial vasodilation, probably during a stage of a particularlydepressed ventricular compliance.     

Carcinoma of the alimentary canal — A statistical study based on autopsy data from 1928 to 1972

Summary An analysis of autopsy data shows that during the period 1928–1972 the relative frequency of carcinoma of the stomach has remained practically unchanged. A similar trend is apparant from the mortality statistics for Vienna from 1955 to 1972. Whereas for the lower and middle age groups there is a real decrease during the period 1928–1952, an opposite trend is visible for the highest age group. The stomach and the lower parts of the large intestine are the most frequent sites of carcinoma of the alimentary canal. The frequency distribution is explained on the basis of the contact hypothesis.     

Airway responses to antigen challenge in allergic rhinitis and allergic asthma

The density dependence of the maximum expiratory flow-volume curve, functional residual capacity (FRC), and specific airway conductance (SGaw) were determined before and during bronchial provocation with ragweed extract in 27 subjects with ragweed hypersensitivity and a history of either bronchial asthma (16 subjects) or allergic rhinitis (11 subjects). Mean baseline SGaw was significantly lower while mean volume of isoflow (Visov) and FrC were significantly higher in subjects with bronchial asthma. During antigen challenge, 10 of 16 subjects with bronchial asthma (63%) and five of 11 subjects with allergic rhinitis (45%) showed a greater than 35% decrease in SGaw ("reactors"): mean relative decreases in SGaw from baseline were 46% and 53%, respectively. The remaining subjects showed a less than 35% decrease in SGaw ("nonreactors") with mean relative decreases of 9% (allergic asthma) and 6% (allergic rhinitis). Mean Visov increased in all subjects with bronchial asthma and in eight of 11 subjects with allergic rhinitis. A significant increase in FRC (6%) was seen only in the "reactors" with bronchial asthma. Following antigen challenge, the beta adrenergic agonist, isoetharine, increased SGaw and decreased Visov. We conclude that in asymptomatic subjects with ragweed hypersensitivity, (1) central and peripheral airway function is more abnormal in subjects with bronchial asthma than in subjects with allergic rhinitis, (2) subjects of both groups show quantitatively and qualitatively comparable airway responses during antigen challenge with a decrease in SGaw or an increase in Visov, possibly representing increase in central and/or peripheral airflow resistance, respectively, (3) Visov may be a more sensitive indicator of airway response to antigen challenge than SGaw, and (4) the bronchodilator effects of a beta adrenergic agonist on antigen-induced bronchospasm are similar in both groups.     

Hormone changes induced by 37.5-h head-down tilt (−6°) in humans

Endocrine regulation of hormones and electrolytes during 37.5 h of –6° head down tilt (HDT) was studied in 13 men. The acute effects of simulated weightlessness are today well documented, but no study has been made concerning the hormone changes between 12 h and 2 days of HDT. Plasma volume showed a maximal increase of 9.23 (SEM 1.97) % after 6.5 h (P<0.01) and had returned to prestudy levels after 13.5 h of HDT. From 1.5 h to 4 h of HDT, C-terminus and N-terminus atrial natriuretic peptide (ANP) concentrations in plasma were increased by about 50% (P<0.01) and thereafter declined to pre-HDT levels. Plasma renin activity (PRA) was decreased by 47% (P<0.05) after 4 h of HDT; PRA increased after 23.5 h to 60%; noradrenaline concentration decreased immediately and remained low up to 37.5 h. Diuresis and natriuresis were evident during the 1st day of HDT, resulting in a marked increase in the urinary Na⁺. These results showed that the initial hormone (ANP, PRA) changes during HDT did not last more than 13.5 h and that after 24 h a new state would seem to have been established to adapt the body to hypovolaemia.     

Role of H+ ions in volume and voltage of epithelial cell nuclei

Condensation of chromatin depends upon the ion composition in the cell nucleus. We tested in isolated nuclei of Madin-Darby canine kidney cells the influence of various ions on nuclear volume (i. e. DNA packing) and intranuclear voltage. After isolation, nuclei were superfused with cytosolic solutions in which Na⁺, K⁺, Ca²⁺ and H⁺ ions were varied. With video-imaging and microelectrode techniques nuclear volume and intranuclear potential were measured in response to the various ions. In control cytosolic solution, isolated nuclei exhibited an intranuclear electrical potential of –6.5±0.5 mV (relative to a reference electrode in the cytosolic solution) corresponding to a nuclear volume of 250±10 fl (n=104). Changing the Na⁺, K⁺ or free Ca²⁺ concentration in the superfusate in the physiological range resulted in minor changes of volume and intranuclear potential whereas pH altered both parameters dramatically. Nuclear swelling and intranuclear negative voltage increased with alkalinization and decreased when pH was reduced. An intact nuclear envelope was found to be no prerequisite for maintaining intranuclear negativity, indicating that the composition and functional state of nuclear chromatin rather than specific ion permeabilities of the nuclear envelope determine nuclear electrical potential. We present a model that explains nuclear volume and voltage on the basis of interaction between negatively charged DNA and positively charged histones of the nuclear chromatin.     

Early effects of aldosterone on the basolateral potassium conductance of A6 cells

Summary Aldosterone increases the basolateral conductance in target epithelia. The basolateral membrane of tight epithelia contains two different types of K⁺ conductances (G_K), a resting and a volume-activated G_K. We have studied the early effects (at 4 hours) of 500 nmol/l aldosterone on the basolateral membrane G_k of A6 cells (a Xenopus laevis kidney cell line), after the permeabilization of the apical membrane with amphotericin B. In the presence of a 97 to 3 mmol/l apical to basolateral K⁺ gradient, the resting, inward rectifying G_K was similar in control and aldosterone treated cells. In contrast, aldosterone induced a 2-fold increase of the volume-activated quinidine sensitive G_K.