Previous studies have suggested that intravenous transplantation of mesenchymal stem cells (MSCs) in rat ischemia models reduces ischemia-induced brain damage. Here, we analyzed the expression of neurotrophic factors in transplanted human MSCs and host brain tissue in rat middle cerebral artery occlusion (MCAO) ischemia model. At 1 day after transient MCAO, 3 x 10(6) immortalized human MSC line (B10) cells or PBS was intravenously transplanted. Behavioral tests, infarction volume, and B10 cell migration were investigated at 1, 3, 7, and 14 days after MCAO. The expression of endogenous (rat origin) and exogenous (human origin) neurotrophic factors and cytokines was evaluated by quantitative real-time RT-PCR and Western blot analysis. Compared with PBS controls, rats receiving MSC transplantation showed improved functional recovery and reduced brain infarction volume at 7 and 14 days after MCAO. In MSC-transplanted brain, among many neurotrophic factors, only human insulin-like growth factor 1 (IGF-1) was detected in the core and ischemic border zone at 3 days after MCAO, whereas host cells expressed markedly higher neurotrophic factors (rat origin) than control rats, especially vascular endothelial growth factor (VEGF) at 3 days and epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) at 7 days after MCAO. Intravenously transplanted human MSCs induced functional improvement, reduced infarct volume, and neuroprotection in ischemic rats, possibly by providing IGF-1 and inducing VEGF, EGF, and bFGF neurotrophic factors in host brain.

Aims-To identify the patent ductus arteriosus (PDA) shunt flow pattern using Doppler echocardiography; and to assess whether it could be used to predict the development of clinically significant PDA. Methods-Premature infants weighing under 1500 g, who required mechanical ventilation, and in whom daily echocardiography could be performed from day 1 until the ductus closed, and on day 7 to confirm closure, were studied. The PDA shunt flow was identified from four Doppler patterns, and the closed pattern of a closed duct was also presented. Clinically significant PDA was diagnosed when there was colour Doppler echocardiographic evidence of left to right ductal shunt associated with at least two of the following clinical signs: heart murmur (systolic or continuous); persistent tachycardia (heart rate>160/min); hyperactive precordial pulsation; bounding pulses; and radiographic evidence of cardiomegaly or pulmonary congestion. Results-Of 68 infants enrolled into this study, clincally significant PDA developed in 31. The most recordable sequence of transition change of shunt flow pattern for clinically significant PDA was: pulmonary hypertension pattern, to growing pattern, to pulsatile pattern, to closing pattern, to closed pattern. And that for non-clinically significant PDA was: pulmonary hypertension pattern, to closing pattern, to closed pattern. The growing and the pulsatile patterns were mostly documented in infants with clinically significant PDA. The first documented growing pattern to predict clinically significant PDA gave a sensitivity of 64.5% and a specificity of 81.1%; the first documented pulsatile pattern gave a sensitivity of 93.5% and a specificity of 100%. Conclusion-Doppler echocardiographic assessment of PDA shunt flow pattern during the first 4 days of life is useful for predicting the development of clinically significant PDA in premature infants. At that stage, the closing or closed Doppler pattern indicates that infants are not at risk of developing clinically significant PDA; the growing or pulsatile Doppler pattern indicates a continuing risk of developing clinically significant PDA. (Arch Dis Child 1997;77:F36-F40)

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The spacial extent of the source region of Pc 1 geomagnetic pulsations is investigated with respect to several such events recorded simultaneously at thirteen stations in Canada. The investigation is based on amplitude distribution obtained through reduction of the data acquired with induction magnetometers at those stations.Propagation from the source region is not isotropic but tends to align with geomagnetic latitude and longitude. The spacial gradient of amplitude near the source region becomes as large as 10 dB/100 km. Left-hand polarization does not seem to be confined to the source region. Size of source regions is discussed.

Doppler frequency changes for a vertically incident and reflected radio wave caused by a redistribution of electrons in the ionosphere due to drift motions set up by an electric field across the earth's main magnetic field are discussed. The Doppler frequency change is given as a linear function of the two horizontal components of the electric field with coefficients which are functions of the relevant ionospheric parameters and the frequency of the sounding radio wave. The Doppler frequency. change can also be given as a function of the intensity of the magnetic variation, provided that a suitable relation can be found between the intensity of the magnetic variation observed on the earth's surface and the intensity of the electric field in the ionosphere. The Doppler frequency change has been given in this way for two cases; one is for a uniform time‐changing magnetic field parallel to the geomagnetic axis which roughly represents the Chapman‐Ferraro field for sudden commencements of geomagnetic storms. The other is for the field due to alternating electric currents in the ionosphere. Several theoretical predictions have been made which can be compared with observations. The amount of the Doppler shift is about 1 c/s in middle latitudes for a 4‐Mc/s sounding wave for a sudden commencement with a time scale of 4 min, and magnitude several tens of gammas. The Doppler shift due to alternating currents in the ionosphere amounts to only 1 c/s for a 4‐Mc/s radio wave with a 50‐y amplitude of oscillation in the magnetic field intensity.