The influence of posture upon cardiovascular dynamics throughout pregnancy

Systemic blood pressure (measured with a zero-randomized sphyngmomanometer), stroke volume and heart-rate (measured with a Minnesota Impedance Cardiograph), hematocrit and their derivatives — cardiac output, pulse pressure, mean arterial blood pressure and peripheral vascular resistance, were assessed in 19 nonpregnant women of child-bearing age and in 27 patients who were examined at regular intervals on 12 to 15 occasions from 8 to 11 wk of pregnancy until 6-wk postpartum. Readings were made with the subjects in each of six positions: supine, reclining, left and right lateral, left and right tilt. The purpose of this paper is to compare the results of these different postures.Systolic and diastolic blood pressure readings were lowest in the left lateral and second lowest in the left tilt. We suggest that this reflects a hydrostatic pressure difference. Stroke volume and cardiac output were lowest in the right lateral and second lowest in the right tilt. Thus, the derived values of peripheral resistance were lowest when subjects were turned towards the left and highest when turned towards the right.The rank orders of values were maintained with impressive consistency between subjects (pregnant and nonpregnant) and throughout pregnancy, reaching levels of statistical significance in almost all instances. No evidence was found that aortocaval compression led to a change in the measured attributes of central cardiovascular dynamics. For the ‘normal unembarrassed parturient’ it is suggested that aortocaval compression is rapidly succeeded by a restabilization of these attributes to their previous levels, reflecting the prompt establishment of a suitably diminished circulating blood volume within a reduced vascular capacity. It is nevertheless likely that aortocaval compression will interfere markedly with uteroplacental vascular dynamics and hence pose a hazard to the fetus.     

Postural and Time-Dependent Effects on Body Height and Scoliosis Angle in Adolescent Idiopathic Scoliosis

Changes in body height and scoliosis angle under the influence of gravity were studied in 40 patients with adolescent scoliosis. The average decrease in body height was 1% during a day. There were no significant changes in the mean angles of the scoliosis curves during the day. The patients were grouped according to age, standing and sitting heights, weight and skeletal maturation. A decrease in the scoliosis angles occurred in younger, more skeletally immature and lighter individuals, while an increase occurred in older, more skeletally mature and heavier individuals.

The difference between the scoliosis angles measured from standing and supine views was also analyzed. The correction of the scoliosis angle in the supine position was on average 19%. No correlation was found between the change in angle and any of the growth factors studied. There was also no correlation between the change in angle and the degree of curvature.     

Effects of body posture on local sweating and sudomotor outflow as estimated using sweat expulsion

To estimate the effects of changes in body posture on sudomotor function, sweat rates on the forearm, chest and thigh, tympanic temperature (Tty), and skin temperatures were recorded in an upright sitting and a supine position under a hot environment of 40 degrees C Ta and 40% relative humidity for 60 min. Sweat expulsions were identified on sweat rate curves and their rates (Fsw) were calculated. Tty was higher, and its initial fall was greater, in the supine position than in the sitting position. On the forearm and the chest, the regression line relating sweat rate to mean body temperature (Tmb) had a gentler slope in the supine position, whereas on the thigh, it showed a steeper slope. The regression line relating Fsw to Tmb had a steeper slope in the supine position than in the sitting position, suggesting that the gain in the mechanisms for central integration and rhythm-generation was enhanced in the supine position. The parameter of sweat rate divided by Fsw was lower on the forearm and the chest, whereas it was higher on the thigh in the supine position than in the sitting position, suggesting that sudomotor outflow was modified at the spinal cord in association with skin pressure. It was concluded that body posture affects sudomotor functions through both brain and spinal mechanisms.     

Maintenance of equilibrium during tracing eye movements

Horizontal tracing movements of eyes modify the type of vertical posture maintenance decreasing the role of the lower segment in the regulation of the position of the pressure center. The relationship between fluctuations of the pressure center in the frontal and sagittal planes increases. Periodicity of eye movements corresponds to fluctuations of the pressure center and these signals were phase shifted relatively to each other. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 138, No. 8, pp. 152–158, August, 2004 The study was supported by the Russian Foundation for Basic Research (grant No. 01-04-49489).     

Maintenance of Equilibrium during Tracing Eye Movements

Horizontal tracing movements of eyes modify the type of vertical posture maintenance decreasing the role of the lower segment in the regulation of the position of the pressure center. The relationship between fluctuations of the pressure center in the frontal and sagittal planes increases. Periodicity of eye movements corresponds to fluctuations of the pressure center and these signals were phase shifted relatively to each other.     

Diaphragmatic motion in the sitting and supine positions: Healthy subject study using a vertically open magnetic resonance system

PURPOSE: To determine the postural difference of diaphragmatic motion between the sitting and supine positions. MATERIALS AND METHODS: A total of 10 healthy men were examined using a vertically open 0.5-T magnetic resonance (MR) system. A total of 40 sequential MR images were obtained in both the sitting and supine positions during two to five respiratory cycles. The diaphragmatic excursions (DEs) were measured on three diaphragmatic points of six sagittal planes for both positions. The differences in DEs between the anterior and posterior parts of the diaphragm were also determined. RESULTS: DEs in the supine position were significantly greater than those in the sitting position at 15 of the 18 points. In five of the six sagittal planes, the difference of DE between posterior and anterior points was significantly larger in the supine position than in the sitting position. CONCLUSION: Diaphragmatic movement in the supine position is greater than that in the sitting position, especially in the posterior part of the diaphragm.     

Intrinsic activity and comparative molecular dynamics of buspirone analogues at the 5-HT(1A) receptors

In CNS, the 5-hydroxytryptamine(1A) (5-HT(1A)) receptors exist in two different populations with different behavioural and physiological effects: (1) somatodendritic autoreceptors located pre-synaptically of 5-HT containing neurons and (2) receptors located post-synaptic to 5-HT containing neurons. Clinical studies have shown that 5-HT(1A) partial agonists have anxiolytic properties, while antagonists of pre-synaptical autoreceptors shorten the onset time of selective serotonin reuptake inhibitors (SSRIs). In the present study, the pre- and post-synaptic activity of structural analogues of buspirone was evaluated in animal models. A three dimensional model of the 5-HT(1A) receptor was used to study their interaction modes and helical displacements upon receptor binding. The predicted receptor-ligand interactions indicated similarities in the receptor binding modes for all buspirone analogues, and no clear relationship between receptor contact residues and activity at pre- and post-synaptic receptors. Comparative molecular dynamics (MD) simulations for 650ps indicated that pre-synaptic antagonistic behaviour is connected to large displacements of transmembrane helix (TMH) 7 upon binding, while pre-synaptic agonistic behaviour is connected to large displacements of TMH2 and small displacements of TMH7. Post-synaptic partial agonist behaviour is connected to large displacements of TMH4 and TMH5 upon binding, while post-synaptic antagonists only slightly displace these helices.     

坐位及仰卧位人眼屈光状态的改变

目的 探讨在坐位及仰卧位人眼球镜度数及散光轴向的改变.设计 前瞻性病例系列.研究对象 拟行LASIK手术的近视患者52例(96眼),屈光度-2.50D～-10.00 D,散光-0.75D～-4.50 D.方法 对所有患者用手持自动验光仪分别测量坐位及仰卧位时的球镜度数、柱镜度数及其轴向,并对坐位及仰卧位球镜度数、柱镜度数及散光轴向的改变进行统计学分析.主要指标 球镜、柱镜度数及散光轴.结果 仰卧位球镜度数(-5.31±3.43)D与坐位球镜度数(-5.27±3.24)D相比略增高,但差异无统计学意义(P=0.25).散光度数坐位平均(-2.27±1.24)D,仰卧位平均(-2.35±1.19)D,差异无统计学意义(P=0.20).眼球散光轴向改变在-16°～ 18°之间,其中0°～2°者52.1%,6°～10°者5.2%,>10°者3.1%.散光轴向右眼在旋转方向上更倾向于逆时针旋转,而左眼更倾向于顺时针旋转.结论 患者坐位及仰卧位眼球的球镜和柱镜度数无明显变化,但眼球旋转引起的散光轴向改变,可能是影响某些患者LASIK术后效果的主要原因之一.     

西洋参质量的化学模式识别

运用模糊动态聚类分析法对来源于美国,加拿大及我国的共１４种不同产地的西洋参样品质量进行了模糊识别研究,经与权威部门认定的具有法定地位的西洋以磁地进行验证,核对,取得了较为一致的结果,为西洋参的质量评价提供了依据。     

佘山羊奶子的某些营养成分分析

<正>佘山羊奶子(Elaeagnus argyi Levl),胡颓子科(Elaeagnaceae),胡颓子属(elaeagnus),常绿或落叶小灌木。佘山羊奶子野生资源非常丰富,常生于海拔100～300 m山坡树林下或林缘灌丛的阴湿环境下,耐干旱瘠薄,适应性强,对土壤要求不严,繁殖容易,结果早,加之营养价值高,开发利用前景非常广阔。我国佘山羊奶子主要分布于江苏、安徽、浙江、江西、河南、湖北、湖南、上海等地[1]。佘山羊奶子果实酸甜爽