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To elucidate the role and pathological dynamics of activated microglia, this study assessed the phagocytic, immunophenotypic, morphological, and migratory properties of activated microglia in the medial forebrain bundle (MFB) axotomized rat brain. Activated microglia were identified using two different monoclonal antibodies: ED1 for phagocytic activity and OX6 for major histocompatibility complex (MHC) class II. Phagocytic microglia, characterized by ED1-immunoreactivity or ED1- and OX6-immunoreactivity, appeared in the MFB and substantia nigra (SN) as early as 1-3 days post-lesion (dpl), when there was no apparent loss of SN dopamine (DA) neurons. Thereafter, a great number of activated microglia selectively adhered to degenerating axons, dendrites and DA neuronal somas of the SN. This was followed by significant loss of these fibers and nigral DA neurons. Activation of microglia into phagocytic stage was most pronounced between 14 approximately 28 dpl and gradually subsided, but phagocytic microglia persisted until 70 dpl, the last time point examined. ED1 expression preceded MHC II expression in phagocytic microglia. All phagocytic microglia sticking to DA neurons showed activated but ramified form with enlarged somas and thickened processes. They were recruited to the SNc from cranial, dorsal and ventral aspects along various structures and finally stuck to DA neurons of the SNc. Characteristic rod-shaped microglia in the white matter were thought to migrate a long distance. The present study strongly suggests that neurons undergoing delayed neurodegeneration may be phagocytosed by numerous phagocytic, ramified microglia at various sites where specific surface signals are exposed or diffusible molecules are released., ((c) 2005 Wiley-Liss, Inc.)

In a stereoscopic full-color LED display by use of a parallax barrier, we discuss optimization of the viewing area, which depends on the width of the black regions between LEDs. Although conventional stereoscopic displays use a parallax barrier to permit the viewer to view stereoscopic images without any special glasses, their viewing area is restricted by crosstalk and the disappearing of pixels. Widening of the viewing area is examined by use of full-color panels with black regions having different widths. The optimum aperture ratio of the parallax barrier is obtained by analyzing the viewing area. An enlarged viewing area has been demonstrated by use of a 3-in-1 chip LED panel that has wider black regions than ordinary LED lamp cluster panels.

Focal microglial activation and progressive dopaminergic neurodegeneration in substantia nigra compacta (SNc) have characterized Parkinson's disease (PD). We have hypothesized that the microglial response may be provoked by molecular signals from chronically stressed SNc neurons. To test whether amyloid precursor protein (APP) could serve as such a signal, we evaluated microglial activation in SN after unilateral transection of the medial forebrain bundle (MFB) in mice either wild-type (WT) or null (KO) for APP. WT and KO mice displayed comparable microglial response at the MFB transection site. In WT mice microglial activation was first apparent in the ipsilateral SN at 3 days postlesion (dpl), marked by morphological change and increased isolectin immunoreactivity. The microglial response intensified at 7 dpl and persisted in the medial nigra through 14 dpl. In contrast, in KO mice activated microglia appeared predominantly at 7 dpl, with little activation at 3 dpl and none at 14 dpl. Neuron number in affected WT SNc at 14 dpl was significantly reduced compared with loss in affected KO SNc. The delayed and limited local microglial activation and increased neuron survival in response to distal axotomy of SNc neurons in APP KO mice are consistent with the important role APP in neuronal stress responses in vivo., (Copyright 2002 Wiley-Liss, Inc.)

In hepatic surgery, the number of repeated hepatectomy has increased for recurrent tumors after the first hepatectomy. We examined here, whether or not hepatic regeneration after the second partial hepatectomy was similar to that of the remnant liver after the primary partial hepatectomy. Using a new model of a second partial hepatectomy in rats, three groups of rats were studied. Group I rats underwent a standard one-third partial hepatectomy (P-PHx group, n=30). Group II rats underwent a one-third hepatectomy 2 weeks after a two-thirds hepatectomy was performed (S-PHx group, n=30). As a control, Group III rats underwent sham surgery. In each group, the rats were sacrificed at different time points postoperatively to evaluate changes in blood chemistry and to estimate the liver regenerative response in the remnant liver (weight, immunohistochemistry; BrdU, MIB-5) as well as expression of the hepatocyte growth factor. In the S-PHx group, a significant decrease was detected in the restitution of the liver mass until 24 h postoperatively which was closely associated with the number of mitotic hepatocytes. The S-PHx group showed significant signs of liver dysfunction until 48 h and significantly increased serum hyaluronic acid levels until 72 h in comparison to the P-PHx group. In situ RT-PCR analysis indicated that in the P-PHx group HGF transcripts were expressed between 24 and 48 h in the remnant liver, while in the S-PHx group HGF transcripts were expressed only at 24 h postoperatively. Our findings suggested that second partial hepatectomized rats exhibit a retarded hepatic regeneration during the early postoperative phase due to a depressed HGFmRNA expression.