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.     

La autoantigen translocates to cytoplasm after cleavage during granzyme B-mediated cytotoxicity

Our recent report demonstrated that apoptosis-specific autoantibodies against granzyme B-induced cleavage fragments of SS-B (La) were found in the sera from patients with primary Sj?gren's syndrome. The objective of this study was identified by the intracellular redistribution of La autoantigen during granzyme B-induced apoptosis. We developed green fluorescence protein (GFP)-La and GFP-LaDelta220 (generation of granzyme B-specific cleavage of La protein) fusion proteins. GFP-La protein was localized in the nucleus, whereas the GFP-LaDelta220 protein predominantly existed in the cytoplasm in transformed A293T cells. Nuclear GFP-La protein was translocated to cytoplasm after granzyme B enriched YT cells incubation. La protein in human salivary grand HSG cells is cleaved and translocated from the nucleus to the cytoplasm after YT cell co-cultivation. These results suggest that La protein is cleaved by granzyme B and N-terminal La fragment (27 kD) translocated to the cytoplasm, thus leading to a novel autoantibody production during granzyme B-mediated cytotoxicity.     

Regulation of apoptosis by glutathione redox state in PC12 cells exposed simultaneously to iron and ascorbic acid

We previously reported that the levels of non-protein-bound iron (NPBI) and ascorbic acid (AA) are markedly increased in the cerebrospinal fluid of infants with perinatal asphyxia. The present study showed that FeSO4 and AA synergistically induced apoptosis of PC12 cells, which was prevented by alpha-tocopherol and glutathione (GSH) ethyl ester. Markers of free radical damage, such as ortho-tyrosine, meta-tyrosine, and F(2alpha)-isoprostane, showed a gradual increase. AA and ferrous NPBI disappeared rapidly from the culture medium, but exposure for only a few hours was sufficient to trigger apoptosis. Intracellular GSH decreased progressively along with a concomitant increase of glutathione disulfide (GSSG). The baseline half-cell reduction potential (Ehc) for GSSG, 2H+/2GSH couple was -246 mV and an Ehc of -200 mV was the critical level to switch on apoptosis, although some cells escaped this fate by transient increase of intracellular GSH. Once Ehc reached around -165 mV (81 mV oxidation from the baseline), all cells lost the ability to maintain an adequate intracellular GSH level and subsequently underwent apoptosis. These findings at least partly explain the mechanism of Fe-AA cytotoxicity, in that ferrous iron catalyzes hydroxyl radical generation and induces lipid peroxidation, after which subsequent depletion of GSH raises Ehc to the critical level for triggering or potentiating the apoptotic cascade.     

Characterization of lacrimal gland carbonic anhydrase VI.

We have previously demonstrated by immunohistochemistry the presence of secreted carbonic anhydrase (CA VI) in the acinar cells of the rat lacrimal glands. In this study we purified the sheep lacrimal gland CA VI to homogeneity and demonstrated by Western analysis that it has the same apparent subunit molecular weight (45 kD) as the enzyme isolated from saliva. RT-PCR analysis showed that CA VI mRNA from the lacrimal gland was identical to that of the parotid gland CA VI mRNA. An RIA specific for sheep CA VI showed the lacrimal gland tissue concentration of the enzyme to be 4.20 +/- 2.60 ng/mg protein, or about 1/7000 of the level found in the parotid gland. Immunohistochemistry (IHC) and in situ hybridization (ISH) showed that lacrimal acinar cells expressed both immunoreactivity and mRNA for CA VI. Moreover, CA VI immunoreactivity was occasionally observed in the lumen of the ducts. Unlike the parotid gland, in which all acinar cells expressed CA VI immunoreactivity and mRNA, only some of the acinar cells of the lacrimal gland showed expression. These results indicate that the lacrimal gland synthesizes and secretes a very small amount of salivary CA VI. In tear fluid, CA VI is presumed to have a role in the maintenance of acid/base balance on the surface of the eye, akin to its role in the oral cavity.     

Changes in membrane constituents and chemiluminescence in vitamin E-deficient red blood cells induced by the xanthine oxidase reaction

The oxidation of vitamin E-deficient rat red blood cells (RBCs) induced by the hypoxanthine-xanthine oxidase (HX-XOD) system has been performed in an aqueous suspension. The generation of chemiluminescence and the accumulation of thiobarbituric acid-reactive substances (TBARS) were observed initially and were followed by hemolysis. Interestingly, the total counts of chemiluminescence were closely related to the amount of TBARS. The predominant change of membrane proteins induced by the reaction was the depletion of spectrin bands in gel electrophoresis. When RBC ghosts were oxidized with HX-XOD, the sulfhydryl (SH) groups of membrane proteins decreased at an early stage of the incubation, which was coincident with the above protein alteration. Membrane alpha-tocopherol suppressed not only the formation of TBARS but also chemiluminescence and hemolysis; nevertheless, it did not inhibit the protein damage and the loss of SH groups. Moreover, it was concluded that the chemiluminescence observed during the oxidation of RBC membranes was associated mainly with the peroxidation of lipids and only to a minor extent with the oxidation of proteins.     

Biochemical characterization of the submicrosomal membrane of the rat brain. Selective solubilization of the components of the light smooth-surfaced membrane by lysophosphatidylcholine

The light smooth-surfaced membrane, one of the three membrane fractions derived from the rat brain microsomal fraction, was fractionated into its soluble and insoluble parts by the use of lysophosphatidylcholine and the chemical composition of these was investigated. Under the condition whereby the maximal amount of the membrane protein was solubilized by lysophosphatidylcholine (0.5% lysophosphatidylcholine at 37 degrees C for 10 min), the insoluble residue, which accounted for approximately 30% of the membrane protein, was ultracentrifugally homogeneous and showed a granular structure under the electron microscope. The lipid composition of the soluble and insoluble fractions, as well as their protein composition, revealed a preferential and limited solubilization of the constituents of the membrane by lysophosphatidylcholine.