Alteration of ryanodine receptor in the hippocampus CA1 after hemispheric cerebral ischemia

Alterations in ryanodine binding and local cerebral blood flow (LCBF) were examined at 30 minutes and 2 hours post-ischemia in the gerbil brain in order to evaluate the influence of cerebral ischemia on the intracellular channels of Ca2+-induced Ca2+ release (CICR). Severe hemispheric cerebral ischemia was induced by occluding the right common carotid artery. LCBF was measured at the end of the experiment using [14C]iodoantipyrine method, and the ryanodine binding was evaluated in vitro using [3H]ryanodine as a specific ligand for CICR channels. An autoradiographic method developed in our laboratory enabled us to determine both parameters within the same brain. A group of gerbils who underwent a sham procedure served as controls. LCBF was found to be significantly reduced in most of the cerebral regions on the occluded side at both 30 minutes as well as 2 hours post-ischemia. In contrast, a significant reduction in ryanodine binding was noted only in the hippocampus CA1 on the occluded side at 30 minutes and 2 hours after the occlusion. These findings suggest that regionally specific changes of CICR may be the cause of decreased ryanodine binding in the hippocampus CA1, and that these changes may be related to the pathophysiological mechanisms that cause this region to be particularly vulnerable to ischemia.     

Immunohistochemical study of calpain-mediated alpha-crystallin proteolysis in the UPL rat hereditary cataract

The purpose of this study is to examine if microencapsulated PC12 cells may provide long term effects to the hemiparkinsonian rats. A modified technique was used to encapsulate PC12 cells into gelled microspheres. We found that the PC12 cells can survive in the modified microcapsules in vitro. Most of the PC12 cells formed cluster 3 weeks after incubation. The PC12 cell-loaded microcapsules were also examined in vitro. Adult Sprague-Dawley rats, anesthetized with chloral hydrate, were injected unilaterally with 6-hydroxydopamine into the medial forebrain bundle. The effectiveness of this lesion was tested by measuring apomorphine or methamphetamine-induced rotation one month after lesioning. The unilaterally lesioned rats were transplanted with microencapsulated PC12 cells. Results showed that apomorphine and methamphetamine-induced rotations were greatly suppressed after transplantation. One year after the grafting, the animals were anesthetized with urethane for the voltammetric study. Low dose of KCl was directly injected into the grafted striatum through pressure microejection. We found that KCl-induced DA release, as measured by voltammetric techniques, was regenerated in the striatum. The animals were later sacrificed for histological examination. We found that capsules were present in the lesioned striatum one year after grafting. Most of the capsules contained no PC12 cell. However, some capsules were filled entirely with PC12 cells. Taken together, our data suggested that PC12 cells can survive in the capsule in vitro and may provide long-term dopaminergic effects to the hemiparkinsonian rats.     

Oligoethylenes in high pressure polyethylene

Summary Series of several alkylated cycloheptanes were detected in some commercial samples of high pressure polyethylene. The structures of the alkylated cycloheptanes were found closely related to the chain transfer agents used in the polymerization process. A probable mechanism involving radical cyclization to cycloheptane structures was presented.     

Determination of standard gibbs energies of formation of Fe2Mo3O12, Fe2Mo3O8, Fe2MoO4, and FeMoO4 of the Fe-Mo-O ternary system and μ phase of the Fe-Mo binary system by electromotive force measurement using a Y2O3-stabilized ZrO2 solid electrolyte

The standard Gibbs energies of formation of Fe₂Mo₃O₁₂, Fe₂Mo₃O₈, FeMoO₄, and Fe₂MoO₄ of the Fe-Mo-O ternary system and the μ phase of the Fe-Mo binary system have been determined by measuring electromotive forces of galvanic cells having an Y₂O₃-stabilized ZrO₂ solid electrolyte. The results are as follows: $$\begin{gathered} \Delta _f G^\circ (FeMoO_4 )/kJ \cdot mol^{ - 1} = - 1053.5 + 0.2983(T/K) \pm 0.4 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_8 )/kJ \cdot mol^{ - 1} = - 2347 + 0.6814(T/K) \pm 1 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_{12} )/kJ \cdot mol^{ - 1} = - 2993 + 0.9105(T/K) \pm 2 \hfill \\ Temperature range: 1040 to 1145 K \hfill \\ \Delta _f G^\circ (Fe_{0.58} Mo_{0.42} )/kJ \cdot mol^{ - 1} = - 18.7 + 0.0117(T/K) \pm 0.1 \hfill \\ Temperature range: 1162 to 1223 K \hfill \\ \Delta _f G^\circ (Fe_2 MoO_4 )/kJ \cdot mol^{ - 1} = - 1174 + 0.342(T/K) \pm 1 \hfill \\ Temperature range: 1243 to 1466 K \hfill \\ \end{gathered} $$ where the standard pressure is 1 bar (100 kPa).     

Ice clouds and Asian dust studied with lidar measurements of particle extinction-to-backscatter ratio, particle depolarization, and water-vapor mixing ratio over Tsukuba

The tropospheric particle extinction-to-backscatter ratio, the depolarization ratio, and the water-vapor mixing ratio were measured by use of a Raman lidar and a polarization lidar during the Asian dust seasons in 2001 and 2002 in Tsukuba, Japan. The apparent (not corrected for multiple-scattering effects) extinction-to-backscatter ratios (Sp) showed a dependence on the relative humidity with respect to ice (RHice) obtained from the lidar-derived water-vapor mixing ratio and radiosonde-derived temperature; they were mostly higher than 30 sr in dry air (RHice < 50%), whereas they were mostly lower than 30 sr in ice-supersaturated air (RHice > or = 100%), where the apparent extinction coefficients were larger than 0.036 km(-1). Both regions showed mean particle depolarization ratios of 20%-22%. Comparisons with theoretical calculations and the previous experiments suggest that the observed dependence of Sp on RHice is attributed to the difference in the predominant particles: nonspherical aerosols (mainly the Asian dust) in dry air and cloud particles in ice-supersaturated air.     

Mode analysis of spreading of partially coherent beams propagating through atmospheric turbulence

The spreading of partially coherent beams propagating through atmospheric turbulence is studied by use of the coherent-mode representation of the beams. Specifically, we consider partially coherent Gaussian Schell-model beams entering the atmosphere, and we examine the spreading of each coherent mode, represented by a Hermite-Gaussian function, on propagation. We find that in atmospheric turbulence the relative spreading of higher-order modes is smaller than that of lower-order modes, whereas the relative spreading of all order modes is the same as in free space. This modal behavior successfully explains why under certain circumstances partially coherent beams are less affected by atmospheric turbulence than are fully spatially coherent laser beams.     

Lipid analog with 2-nitrophenol trigger designed for liposome fusion at physiological pH

A novel lipid analog with two long alkyl (C₁₆) chains, an aspartate skeleton, a connecting alkyl (C₈) chain, and 2-nitrophenol trigger group is synthesized by an efficient synthetic route, which can induce liposome fusion at physiological pH.     

High‐efficiency light‐collection optics for lamp‐based projection TV

Abstract— A new light‐collection optics has been developed that enhances the luminance of projection TV which use lamps as the light source. The conventional optical system consists of an elliptical reflector and a flat‐surface front glass, but these systems cannot sufficiently collect the beams coming from the light source, and they cause loss in the coupling with the light pipe. To solve this problem, we devised a new optical system through a structure of an aspherical reflector and an aspherical front glass. This new optical system concentrates the beams coming from the light source to a smaller point which improves the coupling efficiency. Thus, we have successfully increased the luminance of the projection TV by approximately 10%. This paper reports the design principles of the new optical system and the results of a prototype experiment.     

Study of local intracellular signals regulating axonal morphogenesis using a microfluidic device

The establishment and maintenance of axonal patterning is crucial for neuronal function. To identify the molecular systems that operate locally to control axonal structure, it is important to manipulate molecular functions in restricted subcellular areas for a long period of time. Microfluidic devices can be powerful tools for such purposes. In this study, we demonstrate the application of a microfluidic device to clarify the function of local Ca²⁺ signals in axons. Membrane depolarization significantly induced axonal branch-extension in cultured cerebellar granule neurons (CGNs). Local application of nifedipine using a polydimethylsiloxane (PDMS)-based microfluidic device demonstrated that Ca²⁺ entry from the axonal region via L-type voltage-dependent calcium channels (L-VDCC) is required for branch extension. Furthermore, we developed a method for locally controlling protein levels by combining genetic techniques and use of a microfluidic culture system. A vector for enhanced green fluorescent protein (EGFP) fused to a destabilizing domain derived from E. coli dihydrofolate reductase (ecDHFR) is introduced in neurons by electroporation. By local application of the DHFR ligand, trimethoprim (TMP) using a microfluidic device, we were able to manipulate differentially the level of fusion protein between axons and somatodendrites. The present study revealed the effectiveness of microfluidic devices to address fundamental biological issues at subcellular levels, and the possibility of their development in combination with molecular techniques.