Adrenomedullin in the eye

Adrenomedullin (AM) is a multifunctional regulatory peptide that is produced and secreted by various types of cells. We showed the presence of high concentrations of adrenomedullin-immunoreactivity in the vitreous fluid, and the levels were elevated in patients with proliferative vitreoretinopathy. Furthermore, adrenomedullin mRNA expression levels were elevated in the tissues of intraocular tumors and orbital tumors. Adrenomedullin is produced and secreted by cultured human retinal pigment epithelial (RPE) cells. Inflammatory cytokines and hypoxia are strong stimulators for the adrenomedullin expression in retinal pigment epithelial cells. Adrenomedullin stimulated the proliferation of retinal pigment epithelial cells both under normoxia and hypoxia. Dexamethasone (DEX) increased the adrenomedullin expression in two cultured cell lines of human retinal pigment epithelial cells; ARPE-19 cells and D407 cells, while it had no noticeable effects on the cytokine-induced adrenomedullin expression. These findings suggest that adrenomedullin is involved in the pathophysiology of inflammatory and neoplastic eye diseases as an autocrine or paracrine growth stimulator. The findings on glucocorticoid-induced AM expression raise the possibility that it may be related to the pathogenesis of some eye diseases, such as central serous chorioretinopathy and multifocal posterior pigment epitheliopathy, which are frequently seen in patients treated with high doses of glucocorticoids.     

Activation of histamine H3 receptors inhibits renal noradrenergic neurotransmission in anesthetized dogs

To investigate the possible involvement of histamine H(3) receptors in renal noradrenergic neurotransmission, effects of (R)alpha-methylhistamine (R-HA), a selective H3-receptor agonist, and thioperamide (Thiop), a selective H3-receptor antagonist, on renal nerve stimulation (RNS)-induced changes in renal function and norepinephrine (NE) overflow in anesthetized dogs were examined. RNS (0.5-2.0 Hz) produced significant decreases in urine flow and urinary sodium excretion and increases in NE overflow rate (NEOR), without affecting renal hemodynamics. When R-HA (1 microg x kg(-1) x min(-1)) was infused intravenously, mean arterial pressure and heart rate were significantly decreased, and there was a tendency to reduce basal values of urine flow and urinary sodium excretion. During R-HA infusion, RNS-induced antidiuretic action and increases in NEOR were markedly attenuated. Thiop infusion (5 microg x kg(-1) x min(-1)) did not affect basal hemodynamic and excretory parameters. Thiop infusion caused RNS-induced antidiuretic action and increases in NEOR similar to the basal condition. When R-HA was administered concomitantly with Thiop infusion, R-HA failed to attenuate the RNS-induced antidiuretic action and increases in NEOR. However, in the presence of pyrilamine (a selective H1-receptor antagonist) or cimetidine (a selective H2-receptor antagonist) infusion, R-HA attenuated the RNS-induced actions, similarly to the case without these antagonists. Thus functional histamine H3 receptors, possibly located on renal noradrenergic nerve endings, may play the role of inhibitory modulators of renal noradrenergic neurotransmission.     

Synthesis and chirality analysis of carbocyclic 5'-nor nucleosides.

Achiral carbocyclic "DL-like" 5'-nor nucleosides have been synthesized and analyzed by the chiral capillary electrophoresis to elucidate the "D-like" monomers.     

Genomic construct and mapping of the gene for CMAP (leukocystatin/cystatin F, CST7) and identification of a proximal novel gene, BSCv (C20orf3)

It is proposed that CMAP (leukocystatin/cystatin F, HGMW-approved symbol CST7) expression is correlated with the metastatic potential of malignant tumors. FISH analysis of human and murine CMAP revealed the genomic loci 20p11.21-p11.22 of the human family 2 cystatin cluster and mouse chromosome region 2G1-G3, respectively. Like murine CMAP, the human CMAP gene is constructed from four divided exons, all of which encode the functional domains of the putative translational product. Based on the computational analysis, a novel gene weakly similar to the plant strictosidine synthase, named BSCv (HGMW-approved symbol C20orf3), was identified on the opposite allele at a distance of a few kilobases from the human CMAP gene. In between human CMAP and the BSCv gene, there is a unique tandem repeat sequence. CpG-rich island characteristics and GC-box features normally observed in housekeeping genes were not seen around exon 1 of the CMAP gene, reflecting the restricted expression of CMAP in hematopoietic cells.     

Cytologic finding of chyloascites in lymphangioleiomyomatosis. A case report

BACKGROUND: Lymphangioleiomyomatosis is a rare disease, histologically characterized by an abnormal proliferation of smooth muscle around the lymphatics. Lung is the most common site of involvement, and patients usually present with dyspnea, chest pain, and cough. Chylous pleural effusion and ascites occasionally appear during the course of the disease. There are only a few reports on the cytologic findings in this disease. To our knowledge, the cytologic findings of chylous pleural effusion and chyloascites have not been reported before. CASE: A 23-year-old female presented with chylothorax, chyloascites and a retroperitoneal mass. Cytologic examination of chylous pleural effusion and chyloascites revealed numerous cohesive and thick clusters of cells with a high nuclear/cytoplasmic ratio, oval nuclei and slightly increased chromatin content. Mitosis and necrosis were not observed. Exploratory laparotomy and transbronchial lung biopsy were performed, and the histologic diagnosis was lymphangioleiomyomatosis involving the retroperitoneal lymph nodes, uterine fundus and lungs. Immunohistochemistry showed that the characteristic clusters in chylous fluids were positive for alpha-smooth muscle actin. CONCLUSION: A diagnosis of lymphangioleiomyomatosis is possible from cytologic findings of effusions with the aid of clinical findings.     

p-aminohippuric acid transport at renal apical membrane mediated by human inorganic phosphate transporter NPT1

Organic anions are secreted into urine via organic anion transporters across the renal basolateral and apical membranes. However, no apical membrane transporter for organic anions such as p-aminohippuric acid (PAH) has yet been identified. In the present study, we showed that human NPT1, which is present in renal apical membrane, mediates the transport of PAH. The K(m) value for PAH uptake was 2.66 mM and the uptake was chloride ion sensitive. These results are compatible with those reported for the classical organic anion transport system at the renal apical membrane. PAH transport was inhibited by various anionic compounds. Human NPT1 also accepted uric acid, benzylpenicillin, faropenem, and estradiol-17beta-glucuronide as substrates. Considering its chloride ion sensitivity, Npt1 is expected to function for secretion of PAH from renal proximal tubular cells. This is the first molecular demonstration of an organic anion transport function for PAH at the renal apical membrane.     

Cytokeratins 8 and 19 in the mouse placental development

To investigate the expression and biological roles of cytokeratin 19 (K19) in development and in adult tissues, we inactivated the mouse K19 gene (Krt1-19) by inserting a bacterial beta-galactosidase gene (lacZ) by homologous recombination in embryonic stem cells, and established germ line mutant mice. Both heterozygous and homozygous mutant mice were viable, fertile, and appeared normal. By 7.5-8.0 days post coitum (dpc), heterozygous mutant embryos expressed lacZ in the notochordal plate and hindgut diverticulum, reflecting the fact that the notochord and the gut endoderm are derived from the axial mesoderm-originated cells. In the adult mutant, lacZ was expressed mainly in epithelial tissues. To investigate the possible functional cooperation and synergy between K19 and K8, we then constructed compound homozygous mutants, whose embryos died approximately 10 dpc. The lethality resulted from defects in the placenta where both K19 and K8 are normally expressed. As early as 9. 5 dpc, the compound mutant placenta had an excessive number of giant trophoblasts, but lacked proper labyrinthine trophoblast or spongiotrophoblast development, which apparently caused flooding of the maternal blood into the embryonic placenta. These results indicate that K19 and K8 cooperate in ensuring the normal development of placental tissues.     

Mechanism of alpha-tocopheryl succinate-induced apoptosis of promyelocytic leukemia cells

Selective induction of apoptosis in tumor cells is important for treating patients with cancer. Because oxidative stress plays an important role in the process of apoptosis, we studied the effect of alpha-tocopheryl succinate (VES) on the fate of cultured human promyelocytic leukemia cells (HL-60). The presence of fairly low concentrations of VES inhibited the growth and DNA synthesis of HL-60 cells, and also induced their apoptosis via a mechanism that was inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), an inhibitor of pan-caspases. VES activated various types of caspases, including caspase-3, 6, 8, and 9, but not caspase-1. VES triggered the reaction leading to the cleavage of Bid, a member of the death agonist Bcl-2 family, and released cytochrome c (Cyt.c) from the mitochondria into the cytosol by a z-VAD-fmk-inhibitable mechanism. VES transiently increased the intracellular calcium level [Ca2+]i and stimulated the release of Cyt.c in the presence of inorganic phosphate (Pi). However, high concentrations of VES (approximately 100 microM) hardly induced swelling of isolated mitochondria but depolarized the mitochondrial membrane potential by a cyclosporin A (CsA)-insensitive mechanism. These results indicate that VES-induced apoptosis of HL-60 cells might be caused by activation of the caspase cascade coupled with modulation of mitochondrial membrane function.