Cell surface antigen CD109 is a glycosylphosphatidylinositol (GPI)-linked glycoprotein of approximately 170 kd found on a subset of hematopoietic stem and progenitor cells and on activated platelets and T cells. Although it has been suggested that T-cell CD109 may play a role in antibodyinducing T-helper function and it is known that platelet CD109 carries the Gov alloantigen system, the role of CD109 in hematopoietic cells remains largely unknown. As a first step toward elucidating the function of CD109, we have isolated and characterized a human CD109 cDNA from KG1a and endothelial cells. The isolated cDNA comprises a 4335 bp open-reading frame encoding a 1445 amino acid (aa) protein of approximately 162 kd that contains a 21 aa Nterminal leader peptide, 17 potential Nlinked glycosylation sites, and a C-terminal GPI anchor cleavage-addition site. We report that CD109 is a novel member of the ␣2 macroglobulin (␣2M)/C3, C4, C5 family of thioester-containing proteins, and we demonstrate that native CD109 does indeed contain an intact thioester. Analysis of the CD109 aa sequence suggests that CD109 is likely activated by proteolytic cleavage and thereby becomes capable of thioester-mediated covalent binding to adjacent molecules or cells. In addition, the predicted chemical reactivity of the activated CD109 thioester is complementlike rather than resembling that of ␣2M proteins. Thus, not only is CD109 potentially capable of covalent binding to carbohydrate and protein targets, but the t ½ of its activated thioester is likely extremely short, indicating that CD109 action is highly restricted spatially to the site of its activation. IntroductionTo identify new surface antigens expressed by primitive hematopoietic stem and progenitor cells, we raised a series of monoclonal antibodies (mAbs) against the primitive CD34 ϩ acute myeloid leukemia cell line, KG1a. 1-3 Four of these mAbs-8A3, 7D1, 8A1, and 7C5-recognized a novel glycoprotein of approximately 170 kd that was expressed in a restricted pattern in the hematopoietic compartment and by endothelial cells. 4 Subsequently found to be identified by a number of additional mAbs, this antigen was designated CDw109 in 1993 5 and CD109 in 1996. 6 Antibodies to CD109 recognize monomeric polypeptides of about 170 kd and 150 kd in lysates of KG1a cells, T-cell lines, and activated T lymphoblasts, endothelial cells, and activated platelets. 3,[7][8][9][10][11] Peptide mapping and amino acid (aa) analysis indicate that the 150-kd form is likely derived proteolytically from the 170-kd form. 3,10 An additional band of about 120 kd that is occasionally observed arises through calcium-dependent proteolysis of the larger forms. 3,10 CD109 contains several N-linked endoglycosidase H-sensitive hybrid-type glycans but no O-linked glycans. 3,10 Consistent with this finding, ABH blood group antigens have recently been shown to be carried by platelet CD109. 12 KG1a CD109 is susceptible to cleavage with phosphatidylinositolspecific phospholipase C (PI-PLC), indicating that CD109 is bo...

The biallelic platelet-specific Gov antigen system-implicated in refractoriness to platelet transfusion, neonatal alloimmune thrombocytopenia, and posttransfusion purpura-is carried by the glycosylphosphatidylinositol (GPI)-linked protein CD109. The recent identification of the human CD109 complementary DNA (cDNA) has allowed the molecular nature of the Gov alleles to be elucidated. By using reverse transcriptase-polymerase chain reaction (RT-PCR) to amplify CD109 cDNAs from 6 phenotypically homozygous Gov aa and Gov bb individuals, we have determined that the Gov alleles differ by an A to C single nucleotide polymorphism (SNP) at position 2108 of the cod-

mRNA diversity represents a major theme of neuronal nitric-oxide synthase (nNOS) gene expression in somatic cells/tissues. Given that gonads often express unique and biologically informative variants of complex genes, we determined whether unique variants of nNOS are expressed in the testis. Analysis of cDNA clones isolated from human testis identified a novel, testis-specific nNOS (TnNOS) mRNA transcript. A predicted 3294-base pair open reading frame encodes an NH 2-terminal truncated protein of 1098 amino acids. Measurement of calcium-activated L-[ 14 C]citrulline formation and nitric oxide release in CHO-K1 cells stably transfected with the TnNOS cDNA indicates that this protein is a calcium-dependent nitric-oxide synthase with catalytic activity comparable to that of full-length nNOS. TnNOS transcripts exhibit novel 5 mRNA sequences encoded by two unique exons spliced to exon 4 of the full-length nNOS. Characterization of the genomic structure indicates that exonic regions used by the novel TnNOS are expressed from intron 3 of the NOS1 gene. Although lacking canonical TATA and CAAT boxes, the 5-flanking region of the TnNOS exon 1 contains multiple putative cis-regulatory elements including those implicated in testis-specific gene expression. The downstream promoter of the human nNOS gene, which directs testisspecific expression of a novel NH 2-terminal truncated nitric-oxide synthase, represents the first reported example in the NOS gene family of transcriptional diversity producing a variant NOS protein.

These data demonstrate that neuronavigation-guided cannulation of the foramen ovale can be executed both quickly and safely on an outpatient basis. Additionally, the use of CT with integrated neuronavigation technology provides superior visual-spatial information compared to conventional fluoroscopy, the process of CT scanning, object planning, and neuronavigation-guided intervention can be completed in the same locale, and its application is easy to master and has the potential to enhance procedure tolerability of awake patients.

This study investigated whether there are marked differences in surface markers between rabbit and human mesenchymal stem cells (MSCs). Murine and rabbit MSCs have been reported to be CD90-negative. Rat MSCs have been reported to be CD71-negative. Our previous study also shows that rabbit MSCs are CD29-negative. However, human MSCs are generally considered to be CD29-, CD71-, and CD90-positive. Therefore, the surface markers of human MSCs might differ from those of other species. Rabbit bone marrow MSCs were obtained that had a multi-differentiation potential. The phenotype of these cells was studied using flow cytometry antibodies for 25 rabbit surface markers, namely, CD13, CD14, CD29, CD31, CD34, CD44, CD45, CD49d, CD49f, CD51, CD54, CD59, CD71, CD73, CD90, CD105, CD106, CD133, CD166, MHC I, MHC II, α-smooth muscle actin (α-SMA), cytokeratin, desmin, and vimentin. The phenotype of commercially available human MSCs was similarly studied using antibodies for human surface markers. CD14, CD31, CD34, CD45, CD49d, CD49f, CD51, CD54, CD71, CD106, CD133, MHC II, and cytokeratin were absent from both rabbit and human MSCs, while CD44, α-SMA, and vimentin were present on both cell lines. CD13, CD29, CD59, CD73, CD90, CD105, CD166, and MHC I were present on human MSCs, but not on rabbit MSCs. However, desmin was present on rabbit MSCs, but not on human MSCs. In total, the surface expression of nine markers differed between human and rabbit MSCs, whereas the surface expression of 16 markers was the same in the two cell lines.

Spontaneous intracerebral hemorrhage (ICH) is associated with high rates of mortality and morbidity. Thus, the identification of novel therapeutic agents for preventing strokes and attenuating poststroke brain damage is crucial. Dexamethasone (DEX) is used clinically to reduce edema formation in patients with spinal cord injury and brain tumors. In this study, we sought to elucidate the effects of DEX treatment on apoptosis and inflammation following ICH in rats. A high dose of DEX (15 mg/kg) was administered immediately following ICH induction and again 3 days later. The inflammatory and apoptotic responses in the rat brains were evaluated by using hematoxylin-eosin, terminal deoxynucleotidyl transferase dUTP nick end labeling, Nissl, and neurofilament-H staining. Levels of phosphorylated neurofilaments and apoptosis-related proteins such as B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), caspase-3, and P53 were analyzed by Western blotting. This study shows that rats without ICH that received DEX treatment had a fourfold higher expression of Bcl-2 than sham-operated rats. ICH causes an increase in Bax, cleaved caspase-3, and P53 proteins from 4 hr to 7 days following ICH induction. In comparison with the ICH rats, the ICH/DEX rats showed significantly decreased apoptotic cell death and increased neuron survival and maintained neurofilament integrity in the perihematomal region. DEX increased the Bcl-2/Bax ratio and lowered the expression of cleaved caspase-3 at 12 hr and 5 days. The ICH rats were accompanied by activation of the inflammatory response, and DEX treatment modulated the expression of a variety of cell types and then decreased ICH-induced apoptosis.

This preliminary study demonstrated that the application of MRI and iCT fusion could help with anatomical localization of the trigeminal cistern intraoperatively. The improvement in neuronavigation provides a choice in the treatment of recurrent or persistent trigeminal neuralgia after previous intervention. Long-term follow-up of the result is necessary to evaluate the benefit in terms of durability of therapeutic efficacy.

Metaphysical rationalism, the doctrine which affirms the Principle of Sufficient Reason (the PSR), is out of favor today. The best argument against it is that it appears to lead to necessitarianism, the claim that all truths are necessarily true. Whatever the intuitive appeal of the PSR, the intuitive appeal of the claim that things could have been otherwise is greater. This problem did not go unnoticed by the great metaphysical rationalists Spinoza and Leibniz. Spinoza’s response was to embrace necessitarianism. Leibniz’s response was to argue that, despite appearances, rationalism does not lead to necessitarianism. This paper examines the debate between these two rationalists and concludes that Leibniz has persuasive grounds for his opinion. This has significant implications both for the plausibility of the PSR and for our understanding of modality.