Effectiveness of a computer tailored physical activity intervention in adolescents compared to a generic advice

Objective

To investigate the differences in effects of a computer tailored physical activity advice as compared to generic information in adolescents.

Methods

Students (mean age, 14.6 ± 1.2) out of 90 classes from six different Flemish schools were randomly assigned to the tailored intervention (n = 563) or the generic non-tailored intervention (n = 608) condition. Both interventions included information on public health recommendations and tips on becoming more active. Participants in both groups received their assessment and feedback at baseline, at 4 weeks and at 3 months during school hours. Physical activity levels were determined using an adolescent adaptation of the International Physical Activity Questionnaire (IPAQ).

Results

After 4 weeks, almost all physical activity scores increased over time in both the generic and the tailored intervention group. No differences between groups were found (all F ≤ 0.07). After 3 months, the generic intervention was more effective for increasing ‘walking in leisure time’ among students not complying with recommendations. For all other physical activity scores, no differences between groups were found (all F ≤ 2.3).

Conclusions

In contrast to the expectations, changes in physical activity scores did not differ between the tailored and the non-tailored intervention group. For most of the physical activity scores increases were found in both groups.     

Blood pressure changes validate phase related external suction,a controlled method for stimulation of human baroreceptors

Summary Phase related external suction (PRES), a new controlled method for manipulating activity in human baroreceptors, applies precisely timed bursts of suction and pressure within the cardiac cycle through an external neck cuff. Seven healthy adult men participated in 32 pseudo-random trials of baroreceptor stimulation and inhibition. Blood pressure was assessed both intra-arterially and with a noninvasive device. In the present study, PRES baroreceptor stimulation elicited invasively measured blood pressure decreases of about 2.5 mmHg (0.33 kPa) and heart rate decreases of about 5 beats · min^–1, while baroreceptor inhibition increased invasively measured blood pressure by about 1.5 mmHg (0.20 kPa) and heart rate about 2.5 beats · min^–1. It was concluded that PRES is an effective method for baroreceptor manipulation with weaker size effect but better control of nonspecific factors in human subjects than other baroreceptor manipulation techniques. The noninvasive blood pressure measurement device was less sensitive to experimental variation than was the invasive device.     

Interaction of peripheral and central respiratory drives in cats I. Effects of sodium cyanide as a peripheral chemoreceptor stimulus at different levels of CSF pH

In cats anesthetized with chloralose-urethane, the central respiratory chemoreceptors were exposed to mock CSF of pH 7.02, 7.20, or 7.57. The right carotid body was simultaneously stimulated by intracarotid injections of 40, 80, or 160 μg sodium cyanide in 200 μl Ringer solution. The left carotid nerve and, in some animals, both vagosympathetic truncs were dissected. It could be demonstrated the the increase in ventilation produced by application of NaCN to the peripheral chemoreceptors is significantly larger at high than at low mock CSF pH (i.e. at low than at high central stimulus intensity). In vagotomized cats the responses of V_T and gelai to NaCN similarly depend upon CSF pH; they are somewhat larger, though, than in intact animals. These results are discussed as compared with results reported by different authors. Supported by the Deutsche Forschungsgemeinschaft (Be 477)     

Modelization of a self-opening peripheral neural interface: a feasibility study

In this paper a self-opening intrafascicular neural interface (SELINE) has been modeled using both a theoretical approach and a Finite Element (FE) analysis. This innovative self opening interface has several potential advantages such as: higher selectivity due to its three-dimensional structure and efficient anchorage system. Mechanical, structural and micro-technological issues have been considered to obtain an effective design of the electrode, as a feasibility study of the self-opening approach. A simple framework has been provided to model the insertion and partial retraction into peripheral nerves, resulting in the opening of wings.This integrated approach results in a rational procedure to optimize kinematics, geometry, and structural properties of peripheral interfaces. The design and feasibility study carried out in this work can potentially assure a correct behavior and dimensioning of the neural interface: in this way anomalous breakage should be avoided while mechanical and geometrical biocompatibility should increase.     

AAQUANT: A computer program for quantitative amino acid analysis of proteins and peptides

Quantitative amino acid analysis is an important tool used in the characterization and structural determination of peptides and proteins. A new computer program, AAQUANT, has been developed specifically to aid researchers in analyzing amino acid composition data. AAQUANT calculates amino acid recoveries, including 95% confidence intervals, following acid hydrolysis of peptides and proteins, and also includes useful routines to locate regions of a specified amino acid composition in known protein sequences, compute amino acid composition reports of known protein sequences, generate proteolytic digestion maps of proteins, and create and edit protein sequence data files. This report describes the AAQUANT routines, and demonstrates the use of the program.     

Control analysis of the Rose-Hindmarsh model for neural activity

It is well known that vasopressin cells fire action potentialsin bursts, but also have the ability to continuously dischargeor have long periods of silence. Experimentally, various externalstimuli can be applied to the vasopressin cell in order tomanipulate the patterns of discharge observed. In this paper, the Rose–Hindmarsh model is used to describe the dischargingof a single vasopressin cell. The range of parameter valueswhich makes the model display the various patterns observedin vivo are described. It is shown that the model can be controlledto follow desired patterns of discharge and thus mimic externalstimulation.     

Characteristics of fasting and fed myoelectric activity in rat small intestine: evaluation by computer analysis

Evaluation of gastrointestinal myoelectric activity has been limited by the assessment techniques and the complexity of the recorded myoelectric signal. Commonly, myoelectric activity is evaluated as motor patterns, which only gives a semiquantitative measure of myoelectric events within the bowel wall. Using myoelectric recordings from the proximal small intestine in rats, a computerized system for acquisition, storage, display and calculation of characteristics for the myoelectric activity was developed. The software was tested in myoelectric recordings from nine rats in fasting and fed states. All migrating myoelectric complexes (MMCs) during fasting and fed myoelectric patterns were recognized in both digital and analog recordings. Reproduction of myoelectric recordings by the computerized system was indistinguishable from that of the analog system. Employing an appropriate cut-off trigger level and a high sampling frequency, spike potentials were recorded in the proximal jejunum with 0.4 (0.3–0.5) spikes 10 s^-1 during phase 1 of MMC, 19.5 (15.1–23.9) (P<0.001) during phase 2, and 103.8 (97.2–110.5) (P<0.001) during phase 3. In fasted state, MMCs were most frequent in the proximal jejunum whereas fewer were found in the duodenum and distal jejunum. To achieve stable values for MMC cycle length at least four MMCs had to be calculated. After feeding in phase 1, the myoelectric activity increased to 23.8 (13.6–33.9) spikes 10 s^-1 (P< 0.001), whereafter the spiking activity decreased over a period of 2 h until a fasting motor pattern was resumed. It is concluded that computerized technology enables evaluation not only of myoelectric patterns, but also of spiking activity per time unit, i.e. the intensity of myoelectric activity in the gut.     

多视场多参数形态定量分析模块在神经研究领域中的应用

缺血性神经元损伤的性质是神经研究关注的热点。但目前用于区分凋亡与坏死细胞的ＴＵＮＥＬ技术,较易受主观因素的影响。本实验和图像分析技术对缺血动物脑的ＴＵＮＥＬ染色切片进行多场多参数形态定量分析,即细胞形态这亘参数（核面积、周长、直径、形状因子）和含 密度（平均光密度、积分光密度）。本实验结果显示图像分析能提高ＴＵＮＥＬ鉴别凋亡与坏死的灵敏度和精确性,并提供了一种简便快捷的形态定量方法,是在神经研究中     

Evidence for endothelial nitric oxide as a negative regulator of Schwann cell dedifferentiation after peripheral nerve injury

The loss of intimate contact with axons triggers Schwann cells (SCs) to switch from a myelin-producing phenotype to a dedifferentiated, proliferating non-myelin-forming state after nerve injury. SC dedifferentiation is required for effective nerve regeneration. Negative regulators of SC dedifferentiation are promising targets to accelerate function recovery in acquired peripheral neuropathies. We recently reported that nitric oxide (NO) synthesized by endothelial NO synthase (eNOS) slows down functional recovery and axon regeneration after XIIth nerve crushing. This harmful action could be effected by a NO-delaying action on SC dedifferentiation. Adenoviral vectors directing the expression of a dominant negative mutant for eNOS (AVV-TeNOS) or the enhanced green fluorescent protein (AVV-eGFP) were individually injected into the distal stump just after XIIth nerve crushing. Growth-associated protein 43 (GAP-43), strongly over-expressed in dedifferentiated SCs and regenerating axons, was up-regulated in AVV-TeNOS-transduced nerves relative to AVV-eGFP-treated nerves. AVV-TeNOS increased the number of GAP-43-positive cells and bands of Bungner but did not alter the number of Hoechst-positive nuclei relative to AVV-eGFP. These results signal endothelial NO as a negative regulator of the SC dedifferentiation process, but not of SC proliferation rate, after nerve injury. Vascular-derived factors should be taken into account as feasible extrinsic regulators of SC plasticity.     

Verification of the two-dimensional disector, a method for the unbiased estimation of density and number of myelinated nerve fibers in peripheral nerves

Quantification of the number of myelinated fibers in peripheral nerves is a common requirement in quantitative morphology. This parameter provides important information on the consequences of various physiological, pathological and experimental conditions on the nerve structure and is one of the main indicators of success of peripheral nerve repair. In this paper, the theoretical rationale for the application of stereological principles to obtain unbiased estimates of the density and total number of myelinated fibers in peripheral nerves is discussed and a simple stereological method is described. The method is applied together with a systematic random sampling scheme, that was optimized for the purposes of the present study, and with sampling scheme analysis by calculating the coefficient of error (CE). The stereological method, which consists of a two-dimensional variation of the classical disector procedure (two-dimensional disector), and the sampling scheme are verified by comparing estimates with the true density and total number of myelinated fibers in peripheral nerve trunks where true values have been accurately determined by extensive counting. The verification of the 2-D disector method, both of normal and regenerated nerves, showed that estimates of density and total number of myelinated nerve fibers are unbiased. The method also proved to be efficient (time-saving): Estimation of density and total number of myelinated fibers in a single nerve takes about 2-3 hours.     

Artificial neural networks as a method to improve the precision of subcutaneous adipose tissue thickness measurements by means of the optical device LIPOMETER

The LIPOMETER is an optical device for measuring the thickness of a subcutaneous adipose tissue layer. It illuminates the interesting layer, measures the backscattered light signals and from these, it computes absolute values of subcutaneous adipose tissue layer thickness (in mm). Previously, these light pattern values were fitted by nonlinear regression analysis to absolute values provided by computed tomography. Nonlinear regression analysis might provide slight limitations for our problem: a selected curve type cannot be changed afterwards during the application of the measurement device. Artificial neural networks yield a more flexible approach to this fitting problem and might be able to refine the fitting results. In the present paper we compare nonlinear regression analysis with the behaviour of different architectures of multilayer feed forward neural networks trained by error back propagation. Specifically, we are interested whether neural networks are able to yield a better fit of the LIPOMETER light patterns to absolute subcutaneous adipose tissue layer thicknesses than the nonlinear regression techniques. Different architectures of these networks are able to surpass the best result of regression analysis in training and test, providing higher correlation coefficients, regression lines with absolute values obtained from computed tomography closer to the line of identity, decreased sums of absolute and squared deviations, and higher measurement agreement.     

交感神经放电特征分析的研究进展

对交感神经电活动的分析方法进行分类,介绍国外各小组在交感神经放电特征的统计学分析、功率谱分析、非线性动力学分析以及和其它生理指标的多变量耦合分析方面所取得的研究进展,总结当今交感神经电活动分析上存在的问题和缺陷,并展望这一工作的发展趋势。     

A simple method for the evaluation of antiseptic and disinfectant virucidal activity

A simple method for evaluating the virucidal activity of water-soluble antiseptic and disinfectant products using poliovirus type 1 (Sabin strain) is described. Using a commercial concentrator, kinetic studies of four products were carried out. It was shown that 2% glutaraldehyde and 5% povidone iodine are rapidly virucidal. 0.2% glutaraldehyde and 2.5% noxythiolin (37 degrees C) are considerably less effective. 0.05% chlorhexidine digluconate has no virucidal activity.     

Determination of activity of sperm by the light scattering method

The possibility of determining the activity of sperm by means of spectra of scattered light was studied. A homodyne laser optical mixing spectrometer was used for the measurements. Solutions of bovine sperm were used as the test object. The activity of the sperm, determined from the motility of the spermatozoa, may be determined from the half-width of the spectrum of scattered light.All-Union Research and Testing Institute of Medical Engineering, Ministry of Health of the USSR, Moscow. K. I. Skryabin Moscow Veterinary Academy, Ministry of Agriculture of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR L. S. Persianinov). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 240–242, February, 1978.     

Development of a new dynamic method for quantitative evaluation of in vitro hemocompatibility of biomedical materials

In this study a new dynamic method is introduced allowing the estimation of blood cell adhesion on flat test surfaces by measuring the cell loss in the bulk phase of surface contacting test blood under defined rheological conditions. This was achieved by constructing a novel test chamber permitting the contact of small amounts of blood with a large geometrical test surface. The construction consists of a spiral-shaped flow channel of 0.3 cm width, 0.02 cm height and 78 cm length covered with the biomaterials to be tested from both sides. Laminarity of blood flow in the conduit was confirmed theoretically by the calculation of an equivalent to the Reynolds number for curved systems the so-called Dean number. Furthermore, flow laminarity was proved experimentally finding that the flow rate of blood with different hematocrit values was proportional to the hydrostatic pressure applied. The applicability of the novel 'spiral method' for the estimation of hemocompatibility was demonstrated by evaluation of platelet adhesion onto different polymers in comparison to siliconized and fibrinogen coated glass as reference surfaces. Additionally, it was possible under distinct conditions to determine the adhesion of leucocytes and the detachment of platelet aggregates. Therefore, it was concluded that the spiral method can be used for the assessment of the hemocompatibility of flat biomedical polymers. As main advantages of the new method can be considered the high time efficiency and accuracy without labelling or optical detection of adherent cells.     

Initial expiratory activity as a test of respiratory center function

Laboratory of Physiology of Respiration, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR B. I. Tkachenko.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 4, pp. 319–321, April. 1990.