Effects of pulsed ultrasound on embryonic development: an in vitro study

Precursor CD4+ T cells develop into effector Th1 and Th2 cells that play a central role in the immune response. We show that the JNK MAP kinase pathway is induced in Th1 but not in Th2 effector cells upon antigen stimulation. Further, the differentiation of precursor CD4+ T cells into effector Th1 but not Th2 cells is impaired in JNK2-deficient mice. The inability of IL-12 to differentiate JNK2-deficient CD4+ T cells fully into effector Th1 cells is caused by a defect in IFNgamma production during the early stages of differentiation. The addition of exogenous IFNgamma during differentiation restores IL-12-mediated Th1 polarization in the JNK2-deficient mice. The JNK MAP kinase signaling pathway, therefore, plays an important role in the balance of Th1 and Th2 immune responses.     

Contribution of pulsed Doppler echocardiography to ultrasound diagnosis of congenital heart diseases

The authors document the importance of echocardiograhy (ECHO) with special respect to the pulsed Doppler technique (PDE) in the diagnosis of congenital heart diseases. Typical ECHO and PDE findings in atrial and ventricular septal defects, patent ductus arteriosus, valvular stenosis and insufficiency, absence of pulmonary valves, tricuspid and pulmonary atresia, Fallot's tetralogy, arterial trunk, double-outlet right ventricle, transposition of the great arteries, total anomalous pulmonary venous drainage and hypoplastic left-heart syndrome are described. The authors conclude that a combination of M-mode, cross-sectional and pulsed Doppler echocardiography permits a comparatively detailed non-invasive diagnosis of the entire spectrum of congenital heart diseases.     

Effects of pulsed Nd:YAG laser radiation on action potential conduction in nerve fibres inside teeth in vitro

OBJECTIVE: This study aimed to simulate the effects of lasing dentine on pulpal nerve function. METHODS: Rat spinal nerve roots were threaded through the prepared pulp canal of a 10 mm long tooth root segment which was mounted in a perspex bath. The protruding ends of the nerve were placed on platinum wire electrodes used to elicit and to record compound nerve action potentials (CAPs). Laser energy (average power = 0.3-3.0 W) was applied to the surface of the root segment using a pulsed Nd:YAG dental laser (dLase 300). RESULTS: With the laser probe tip placed in static contact with the tooth surface, the nerve CAP was irreversibly abolished within 60 s of lasing at 1.0-3.0 W power. When the laser tip was moved to and fro over the root surface in a scanning mode, similar levels of radiation produced less marked effects. In the latter mode, CAP attenuation increased with increasing power and duration of lasing. After 60 s lasing at 0.3 W, the CAP size was 95% (+/- 5, S.D.) of the prelasing controls value; with 2.0 W the CAP was reduced to 54% (+/- 33). The CAP recovered to 90% of control levels after lasing at powers up to 1.5 W, but reached only 72% of control values after lasing at 2.0 W power. CONCLUSIONS: Laser radiation applied to dentine caused a dose-dependent block of action potential conduction in nerve fibres in the underlying pulp chamber.     

The isolated and perfused working heart of the frog, Rana esculenta: an improved preparation

The present study describes extraction fraction and uptake measurements of the [11C]methyl triphenyl phosphonium (11C-MTP), a promising positron emission tomography (PET) agent for cardiac imaging. PET imaging was performed in mongrel dogs. Under physiological flow conditions 11C-MTP uptake reached a maximum within the first 10 minutes after injection and remained constant during the entire observation period of 80 minutes. Over the same time period, the heart/blood ratio was 46-106:1, and the heart/lung ratio 14:1. Following permanent occlusion of the left anterior descending coronary artery, 11C-MTP uptake in the normally perfused myocardium also reached a maximum at 10 minutes after injection, whereas in the infarcted area there was no significant accumulation of 11C-MTP. For a time period of 80 minutes the noninfarcted/infarcted myocardium ratio was 12:1. Extraction was measured in anesthetized dogs with a double isotope method using 99mTc-HSA as the reference tracer. The extraction fraction was 91% at a flow of 69 mL/min/100g. As flow increased to five-fold (342 mL/min/100g) following administration of adenosine, extraction fell to 61%. Following coronary artery occlusion, the 11C-MTP content in the myocardium was highly correlated (r = 0.93, p < 0.01; y = 10.46 + 0.92x) with the microsphere determined regional myocardial blood flow.     

Effects of electromagnetic radiation of various modes on heart activity (in experiments)

On spinal cord frogs and isolated interauricle to a partition of heart in vivo and in vitro influence the MICROWAVES of a radiation in continuous and modulated modes on function of heart (9.3 Hz is investigated; 0.348-0.16 and 0.016 mV/sm2, modulation from 1 up to 100 Hz). A possibility of influence of an electromagnetic exposure on heart frequency and rhythm is revealed. Pointing of heart in vitro by a neutral red resulted in large number of % of experience in a stop of irradiated heart.     

Effect of pulsed laser radiation on the microstructure of polycrystalline carbides and borides

Translated from Poroshkovaya Metallurgiya, No. 10(322), pp. 52–57, October, 1989.     

Oxidation of porous nanocrystalline titanium nitride. III. Oxidation mechanism

The air oxidation mechanism of nanocrystalline TiN at 500 to 900 °C is examined. It is shown that at t ≤ 800 °C the oxidation of titanium nitride is controlled by the diffusion of oxygen and at t > 800 °C the interdiffusion of titanium ions is observed. The oxidation properties of porous TiN are determined by the chemical interaction of oxygen and the reaction surface, which includes the external surface of samples and the internal surface of the pores into which oxygen penetrates. The time and temperature dependence of the weight increment complies with the porous material oxidation model. Active initial oxidation is due to the interaction of oxygen and large internal surface. Short-term self-heating of porous samples is also possible. At t ≤ 800 °C, the pores are obliterated with oxides with time, the internal reaction surface reduces, an external oxide film is formed, the oxygen diffusion and weight increment slow down, and the process stabilizes. With temperature increase, these processes are activated and lead to a smaller weight increment at the final stage (2 to 4 h) at 800 °C as compared with 600 °C. At t > 800 °C the pore obliteration rate increases, but due to the interaction of oxygen and titanium ions that diffuse into the external scale surface, weight increment continuously increases with both time and oxidation temperature. The phase composition of the scale also affects the oxidation mechanism of porous TiN. Oxynitride of terminal composition plays a protective role; the transformation of anatase into rutile is accompanied by a decrease in the oxygen diffusion rate; Ti₂O₃ formed in pores accelerates their obliteration. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 95–104, 2007.     

A general mechanism of martensitic nucleation: Part III. Kinetics of martensitic nucleation

The growth of martensitic fault embryos in the fault plane, the development of their in-terfacial structure, and the thickening of the embryos normal to the fault plane are ex-amined as possible rate limiting steps in the total martensitic nucleation process. Growth of the embryos in the fault plane appears the most probable rate limiting step, capable of accounting for both the observed isothermal and athermal kinetic behavior depending on the parameters (such as activation volume) which control the motion of the transformational dislocations. The thermally activated nucleation of dislocation loops responsible for lattice invariant deformations is a possible rate limiting step for some isothermal transformations, though such deformations are not required for all marten-sitic transformations. Embryo thickening by the nucleation of discrete loops of trans-formation dislocations appears improbable in bulk material; instead, a plausible pole mechanism for embryo thickening is presented which incorporates existing “forest≓ dislocations intersected by embryos growing in the fault plane. Lattice softening phe-nomena may lower the critical chemical driving force for nucleation, but are not essen-tial for martensitic nucleation by the proposed faulting mechanism. This paper is Part III of a three-part series based on a thesis sub-mitted by G. B. Olson for the degree of Sc.D. in Metallurgy at the Massachusetts Institute of Technology in June 1974.     

A general mechanism of martensitic nucleation: Part III. Kinetics of martensitic nucleation

The growth of martensitic fault embryos in the fault plane, the development of their interfacial structure, and the thickening of the embryos normal to the fault plane are examined as possible rate limiting steps in the total martensitic nucleation process. Growth of the embryos in the fault plane appears the most probable rate limiting step, capable of accounting for both the observed isothermal and athermal kinetic behavior depending on the parameters (such as activation volume) which control the motion of the transformational dislocations. The thermally activated nucleation of dislocation loops responsible for lattice invariant deformations is a possible rate limiting step for some isothermal transformations, though such deformations are not required for all martensitic transformations. Embryo thickening by the nucleation of discrete loops of transformation dislocations appears improbable in bulk material; instead, a plausible pole mechanism for embryo thickening is presented which incorporates existing “forest” dislocations intersected by embryos growing in the fault plane. Lattice softening phenomena may lower the critical chemical driving force for nucleation, but are not essential for martensitic nucleation by the proposed faulting mechanism. This paper is Part III of a three-part series based on a thesis submitted by G. B. Olson for the degree of Sc.D. in Metallurgy at the Massachusetts Institute of Technology in June 1974.     

Dopamine and preparatory behavior: III. Effects of metoclopramide and thioridazine.

The effects of metoclopramide and thioridazine on feeding behaviors of male hooded rats were investigated in 2 experiments. Metoclopramide (2.5–7.5 mg/kg) attentuated conditioned preparatory responses to a conditional stimulus signaling delivery of a meal. However, consummatory responses were affected only by the highest dose. Similar effects had previously been observed following administration of pimozide (J. R. Blackburn et al; see record 1987-30709-001). Thioridazine (10–30 mg/kg) had no significant effect on any measure of feeding behavior. The different effects of the drugs may be related to their preferential actions at dopamine terminals in anatomically distinct regions of the forebrain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anabolic-androgenic steroids: Effects on social behavior and baseline heart rate.

Examined effects of anabolic androgenic steroids on behavior, baseline heart rate (HR), and stress-induced HR responses in 24 monkeys. Ss received 8 wks of im injections of testosterone and were assigned to 4 mixed social groups of both treated and sham control Ss. Testosterone disrupted the social milieu such that all dominant Ss exhibited increased submission. These changes returned to pretest levels 8 wks after termination of the drug intervention. Affiliative behaviors decreased for all Ss as a function of testosterone and, with the exception of play behavior, failed to return to pretest levels after the 8-wk recovery period. Testosterone increased baseline HR, particularly among dominant Ss; subordinate Ss treated with testosterone experienced a decrease in baseline HR from pre- to posttest. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of increased heart rate on intellectual performance.

A significant correlation found in a pilot study between heart rate and digit Symbol performance was utilized to investigate effects of type of arousal induction on performance. 60 Ss were arranged in a 3 X 2 factorial design, divided into high and low drive via heart rate. Ss first performed on a Digit Symbol task; followed by a frustrating experience, physical exertion, or nonfrustrating task; followed by readministration of an alternate form of the 1st Digit Symbol problem. The results showed that the relation between activation and performance, in most instances followed the hypothetical inverted U function. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of response force and intertrial interval on extinction in children.

Gave 64 4-yr-old boys acquisition and extinction training on a lever-pressing task. The 2 * 2 * 2 * 2 design employed 2 force requirements (4 and 80 oz.) and 2 ITIs (5 and 20 sec.) in both acquisition and extinction. The ITI values had no effect on extinction performance, but number of responses to extinction was an inverse function of the force requirements of both acquisition and extinction. Results are discussed in terms of several theories which are pertinent to the effect of force and ITI on extinction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of ionizing radiation on cartilage: emphasis on effects on the extracellular matrix

In this report, we review data dealing with radiation effects on cartilage. More specifically, we emphasize on alterations caused in the extra-cellular cartilage matrix. Although radiation studies predominantly describe the effect on the structure of DNA and on the mitotic activity of cells, alterations caused by the effect on the non-mitotic activity can also be important. Cartilage, having an extracellular matrix composed of 2 major components, aggrecan and collagen, provides a good model to study this kind of radiation effects. The following topics concerning literature data are summarized: effects on the amount of matrix synthesized, effects on the activity of certain enzymes and effects on the structure and morphology of the matrix. Some new findings concerning the radiation effect on the size distribution of aggrecan-aggregate populations, de novo synthesized by chondrocyte cultures, either derived from calcifying or from non-calcifying cartilage, are given.     

Combining B-mode ultrasound with pulsed wave Doppler for the assessment of tubal patency

This study was conducted to determine whether the additional use of pulsed wave Doppler improves the diagnostic capacity in assessing tubal patency by hysterosalpingo contrast sonography (HyCoSy). A total of 210 women with a history of infertility were included in this study. HyCoSy was performed after intrauterine injection of Echovist 200. For the assessment of tubal patency B-mode scanning and pulsed wave Doppler ultrasound were performed in the proximal and distal tubal segments. With the combined sonographic procedure 297 tubes (74%) were rated patent, 35 (8%) incompletely obstructed and 70 (18%) completely obstructed. A total of 252 tubes were additionally examined by laparoscopy for reference purposes. Concordant results for both methods were found in 92% of tubes, nine had been rated false negative and 10 tubes appeared to have been rated false positive. The combined sonographic specificity was found to be 85% with a sensitivity of 95%. Peritubal adhesions detected by laparoscopy were found to be the reason for false positive sonographic results in 60% of cases. In conclusion, the combined B-mode and pulsed wave Doppler examination appears to be a non-invasive and low-cost test for the assessment of tubal patency, which should be performed during diagnostic work-up for infertility.     

Effect of conditioned stimulus intensity on visually conditioned heart rate change in the pigeon: A sensitization mechanism.

In visually conditioned heart-rate change in 30 White Carneaux pigeons, increasing the conditioned stimulus intensity enhanced performance. The effect, which only appeared at high intensity levels, was obtained during acquisition and with rigorous maintenance of constant stimulus conditions. A similar effect was obtained with 10 sensitization control Ss. Evidence is presented that the stimulus intensity effect during conditioning may have totally reflected increased sensitization such that the locus of the effect was upon performance rather than conditioning per se. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of alcohol on autonomic reactivity in alcoholics. Pupillometric studies. III

Measurements of light- and dark-adapted pupil diameters, in alcoholics and nonalcoholics, with and without alcohol are used as an index of autonomic nervous system activity.