Cardiac microdialysis of salicylic acid .OH generation on nonenzymatic oxidation by norepinephrine in rat heart

The effect of pargyline, a monoamine oxidase inhibitor, on the generation of hydroxyl free radicals (.OH) was investigated using cardiac microdialysis. Salicylic acid in Ringer's solution (0.5 nmol x microL(-1) x min(-1)) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium of anesthetized rats. When pargyline (100 nmol x microL(-1) x min(-1)) was infused in rat heart, the level of norepinephrine (NE) gradually increased in a time-dependent manner and an increase of DHBA was also observed. When NE was administered to the pargyline pretreated animals, a marked elevation in the levels of 2,3- and 2,5-DHBA formation was obtained, as compared to the group treated with NE only, showing a positive linear correlation between NE and .OH formation trapped as 2,3-DHBA (R2 = 0.981) or 2,5-DHBA (R2 = 0.984) in the dialysate. NE clearly produced an increase in .OH formation. These results indicate that accumulation of NE in the extracellular fluid elicited by pargyline can be auto-oxidized, which in turn, leads (possibly by an indirect mechanism) to the formation of cytotoxic .OH free radicals.

Aplastic anemia complicating Sjögren's syndrome

A 47-year-old woman was referred to our hospital because of severe anemia and polyclonal gammopathy. She developed sicca syndrome after admission. Laboratory data revealed pancytopenia (white blood cells, 2,800/microliter; hemoglobin, 6.4 g/dl; platelets, 6.1 x 10(4)/microliter) and hyper gamma globulinemia (5.2 g/dl), and bone marrow was hypoplastic. Histology of the salivary gland showed infiltration of lymphocytes. We report a good response to immunosuppressive therapy in a rare case of aplastic anemia complicating Sjögren's syndrome.

Neuronal and muscular inclusions in rats with hindlimb dysfunction after treating with difluorobenzhydrylpiperadine

Rats showing an ataxic gait induced by 20 wk of treatment with 0, 30, or 60 mg/kg of difluorobenzhydrylpiperadine (DFBP), a detriazinyl metabolic of almitrine, were examined by light microscopy and transmission electron microscopy. Vacuolar degeneration associated with lamellar inclusions was observed in musculus soleus and m. interossei of the hindlimbs in DFBP-treated rats. The inclusions were also produced within sensory neurons, satellite and Schwann cells, and vascular endothelial cells of thoracic and lumbar dorsal root ganglia as well as muscle spindles of affected muscles. Membrane-bound vacuoles containing electron-dense granules were seen in the peripheral nerves. This study demonstrated neuronal and muscular toxicity of DFBP in rats.

Tyrosine phosphorylation and p72syk activation by an anti-glycoprotein Ib monoclonal antibody

NNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ib alpha, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-Fc gamma II receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab' fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab' fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the Fc gamma II receptor. Cross-linking of the receptor-bound Fab' fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5-induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.

An alternative pathway for STAT activation that is mediated by the direct interaction between JAK and STAT

JAK is believed to be an essential tyrosine kinase that mediates signals from the cytokine receptor to its downstream events. JAK associates with the cytoplasmic domain of the type I cytokine receptor superfamily and upon the ligand stimulation it can be activated, resulting in the receptor phosphorylation. In signaling from gp130, a common signal transducer for the IL-6 family cytokines, STAT3, a transcription factor that contains an SH2 domain, is recruited by phosphotyrosines on gp130 and is subsequently phosphorylated by gp130-associated JAKs. In this study, we attempted to find a new target for JAK that is directly activated by JAK, independent of gp130 tyrosine phosphorylation, by using a yeast two-hybrid system. In the process we found that the JH2 domain of JAK1, JAK2 or JAK3 could specifically associate with the carboxy-terminal portion of STAT5, but not with STAT3 or STAT1. The interaction was confirmed using both a transient expression system in a cell line and a GST-fusion protein binding assay. Furthermore, we showed that the activation of STAT5 via gp130 did not need any phosphotyrosines on gp130 while that of STAT3 strictly depended on phosphotyrosines on gp130. Mutations of STAT5 that eliminated the interaction with JAK1 reduced the activation of STAT5 upon the gp130 stimulation, although such mutants could be still activated through erythropoietin receptor. These results indicate that STATs are activated through cytokine receptors by two distinct mechanisms, one dependent on receptor tyrosine phosphorylation and the other mediated by the JAK-STAT direct interaction.

Alterations in acetylcholine, NMDA, benzodiazepine receptors and protein kinase C in the brain of the senescence-accelerated mouse: an animal model useful for studies on cognitive enhancers

The senescence-accelerated mouse (SAMP8) is a useful murine model of accelerated aging and learning deficiency. We examined bindings of [3H]pirenzepine, [3H]dizocilpine (MK-801), [3H]flunitrazepam, [3H]8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) and [3H]phorbol 12,13-dibutylate (PDBu) in SAMP8 brains, and compared them to those of SAMR1 (control). In the hippocampus of SAMP8 at 12 months, bindings of [3H]pirenzepine, [3H]MK-801, [3H]flunitrazepam, [3H]8-OH-DPAT and [3H]PDBu were significantly lower than those in SAMR1. In the cerebral cortex, bindings of [3H]pirenzepine, [3H]flunitrazepam and [3H]8-OH-DPAT were higher in SAMP8 than in SAMR1 at 12 months. [3H]PDBu binding was decreased in both the fractions of the membrane and cytosol in the hippocampus of SAMP8. The neurochemical findings presented here support behavioral and pharmacological findings that SAMP8 is a useful model of learning dysfunction and anxiety-deficiency. The usefulness of SAMP8 in studies on cognitive enhancers is also discussed.

Protective effect of carbidopa on hydroxyl radical generation in the rat striatum by dopamine

The effect of L-3,4-dihydroxyphenylalanine (L-DOPA) on the generation of hydroxyl free radicals (.OH) was investigated using striatal microdialysis technique. Salicylic acid in Ringer's solution (0.5 nmol.microliters-1.min-1) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acids (DHBA) in the striatum. When L-DOPA (0.1 mM; 1 microliter.min-1) was infused in the rat brain, the level of 3,4-dihydroxyphenylacetic acid (DOPAC) gradually increased in a time-dependent manner. In addition, a marked elevation of DHBA was observed. However, in the presence of carbidopa, a decarboxylase inhibitor, the elevation in DHBA formation was not observed. These results suggest that carbidopa may suppress the .OH generation by dopamine (DA).

Synthesis and characterization of insulin-like growth factor-binding protein (IGFBP)-7. Recombinant human mac25 protein specifically binds IGF-I and -II

The mac25 cDNA was originally cloned from leptomeningial cells and subsequently reisolated through differential display as a sequence preferentially expressed in senescent human mammary epithelial cells. The deduced amino acid sequence of the human mac25 propeptide shares a 20-25% identity to human insulin-like growth factor-binding proteins (IGFBPs), suggesting that mac25 could be another member of the IGFBP family. In the present study, we have generated recombinant human mac25 (rh-mac25) in a baculovirus expression system and assessed its affinity for IGFs and have evaluated the pattern of expression of the mac25 gene in human tissues. Binding of 125I-IGF-I and 125I-IGF-II to rh-mac25 was demonstrated by Western ligand blotting after nondenaturing polyacrylamide gel electrophoresis and by affinity cross-linking with as little as 2 nM rh-mac25. Specificity of rh-mac25 binding to 125I-IGFs was demonstrated by competition for rh-mac25 binding with unlabeled IGFs, but not with [QAYLL]IGF-II analog, which has 100-fold less affinity for IGFBPs. In comparison with IGFBP-3, rh-mac25 has at least a 5-6-fold lower affinity for IGF-I and 20-25-fold lower affinity for IGF-II. mac25 mRNA was detectable in a wide range of normal human tissues, with decreased expression in breast, prostate, colon, and lung cancer cell lines. In conclusion, mac25 specifically binds IGFs and constitutes a new member of the IGFBP family, IGFBP-7. Its wider distribution in normal tissue and lower expression in several cancer cells indicate that IGFBP-7 may function as a growth-suppressing factor, as well as an IGF-binding protein.

Two signals are necessary for cell proliferation induced by a cytokine receptor gp130: involvement of STAT3 in anti-apoptosis

gp130 is a common signal transducer for the interleukin-6-related cytokines. To delineate the gp130-mediated growth signal, we established a series of pro-B cell lines expressing chimeric receptors composed of the extracellular domain of the granulocyte colony-stimulating factor receptor and the transmembrane and cytoplasmic domains of gp130. The second tyrosine (from the membrane) of gp130, which was required for the tyrosine phosphorylation of SHP-2, its association with GRB2, and activation of a MAP kinase, was essential for mitogenesis, but not for anti-apoptosis. On the other hand, the tyrosine in the YXXQ motifs essential for STAT3 activation was required for bcl-2 induction and anti-apoptosis. Furthermore, dominant-negative STAT3 inhibited anti-apoptosis. These data demonstrate that two distinct signals, mitogenesis and anti-apoptosis, are required for gp130-induced cell growth and that STAT3 is involved in anti-apoptosis.

[Primary biliary cirrhosis with polymyositis successfully treated with prednisolone and ursodeoxycholic acid]

A 65-year-old woman was given a diagnosis of polymyositis in April 1991. She was treated with prednisolone until December 1993, at which time muscle strength had increased and high blood pressure had developed. In May 1994 she was hospitalized for muscle weakness and mild liver dysfunction. Prednisolone was given and the levels of hepatobiliary enzymes decreased. Immunological examination revealed strongly positive results for anti-mitochondria antibody and M-2 antibody, which lead to the diagnosis of primary biliary cirrhosis. administration of ursodeoxycholic acid in addition to prednisolone was followed by normalization of liver function and a decrease in the production of the autoantibodies. Although polymyositis can be complicated by autoimmune diseases, reports of complication by primary biliary cirrhosis are rare, here we report that treatment with the combination of ursodeoxycholic acid and prednisolone was successful in a patient with liver dysfunction and primary biliary cirrhosis.

Effects of bifemelane on muscarinic receptors and choline acetyltransferase in the brains of aged rats following chronic cerebral hypoperfusion induced by permanent occlusion of bilateral carotid arteries

Cerebral hypoperfusion was chronically induced in aged rats via permanent bilateral occlusion of common carotid arteries (2VO). Marked reduction of the Bmax value of the muscarinic receptors (mAChR) in both the cortex and striatum and the Vmax value of choline acetyltransferase (ChAT) activity in the cortex, hippocampus and striatum were observed as compared with those of control aged rats. No significant changes in mAChR and ChAT activity were observed between young control rats and young 2VO rats. One month post-surgery in aged rats, daily doses of bifemelane (10 mg/kg) or aniracetam (50 mg/kg) were administered orally over a 4-week period. Administration of bifemelane significantly increased Bmax values and decreased apparent Kd values for 3H-quinuclidinyl benzilate (QNB) in mAChR in the striatum. Chronic administration of bifemelane or aniracetam also enhanced ChAT activity in the cortex, hippocampus and striatum. In particular, administration of bifemelane resulted in a significant increase in Vmax values of ChAT in all three brain regions, while no significant change in K(m) values for ChAT was observed. These results suggest that bifemelane is responsible for this activity, thereby enhancing the functioning system of CNS cholinergic neurons of cerebral hypoperfused aged rats.

Effect of fluvoxamine on 5-hydroxytryptamine uptake, paroxetine binding sites and ketanserin binding sites in the Japanese monkey brain and platelets, in vivo and in vitro

We investigated the in vitro effects of fluvoxamine on 3H-paroxetine binding and 3H-monoamine uptake in monkey cerebral cortex in comparison with those of other antidepressants. Fluvoxamine selectively inhibited 3H-5-hydroxytryptamine (5-HT) uptake and 3H-paroxetine binding. However, it did not alter 3H-norepinephrine or 3H-dopamine uptake. In addition, we examined the effects of chronic treatment with fluvoxamine (5 mg/kg per day, p.o.) on 5-HT uptake sites that bind 3H-paroxetine and 5-HT2 receptors that bind 3H-ketanserin, in monkey brains and platelets. Chronic treatment with fluvoxamine affected neither the paroxetine binding sites nor the kentanserin binding sites of the brains and platelets. These results suggest that long-term treatment with fluvoxamine does not affect either the 5-HT uptake sites or 5-HT2-receptors of 5-HT neurons in monkey brain in spite of its strong inhibitory effect on 5-HT uptake in vitro.

In vivo monitoring of .OH generation on jejunal ischemic injury by dialysis technique

We applied an in vivo microdialysis technique to examine free radical generation following ischemic injury in the rat jejunum. For this purpose, we used a microdialysis probe holding system. The salicylate reacts with hydroxyl free radical (.OH) and generates 2,3-dihydroxybenzoic acid (DHBA), which can be measured electrochemically in picomole amounts by high-performance liquid chromatography (HPLC). Therefore, the former was used for trapping the .OH formation. Reperfusion of the jejunum produced progressive elevations in the levels of 2,3-DHBA achieving the maximums at 20 min, after which they decreased progressively to the baseline. These elevations were significant only after 10 min- and 20 min-ischemia. However, this change was not significant in the case of 30 min-ischemia. Ischemia-reperfusion of rat intestine caused morphological changes. These results suggest that .OH production is significantly reduced after 30 min-ischemia providing thus the possibility for more severe intestinal damage. In conclusion our dialysis probe can be useful for the measurement of .OH generation following ischemia-reperfusion injury.

A central role for Stat3 in IL-6-induced regulation of growth and differentiation in M1 leukemia cells

Interleukin-6 (IL-6) induces either differentiation or growth of a variety of cells. Little is known about the molecular basis of this cellular decision. The family of signal transducer and activator of transcription (Stat) proteins are involved in signaling through a variety of cytokine and growth factor receptors, although their biological roles have not been established. To address whether Stat proteins play roles in IL-6-induced growth or differentiation, we introduced two types of mutant Stat3 acting in a dominant-negative manner into M1 leukemic cells which respond to IL-6 with growth arrest and terminal differentiation. We show that dominant-negative forms of Stat3 inhibited both IL-6-induced growth arrest at G(0)/G1 and macrophage differentiation in the M1 transformants. Blocking of Stat activation resulted in inhibition of IL-6-induced repression of c-myb and c-myc. Furthermore, IL-6 enhanced the growth of M1 cells primarily through shortening the length of the G1 period when Stat3 was suppressed. Thus IL-6 generates both growth-enhancing signals and growth arrest- and differentiation-inducing signals at the same time. Stat3 may be a key molecule which determines the cellular decision from cell growth to differentiation in M1 cells.

Effects of long-term treatment with dicyclic, tricyclic, tetracyclic, and noncyclic antidepressant drugs on monoamine oxidase activity in mouse brain

1. The individual long-term effects of the antidepressant drugs zimeldine, viloxazine, imipramine, amitriptyline, nortriptyline, maprotiline, or nomifensine, on brain mitochondrial monoamine oxidase (MAO) activity, were studied in mice that were given daily intraperitoneal injections (30 mg/kg) of these reagents for 4 weeks. 2. Both the A-form (MAO-A) and B-form (MAO-B) of MAO were inhibited after long-term administration of all the drugs except nortriptyline (MAO-A was not affected) and maprotiline (neither MAO-A nor MAO-B were affected). 3. Kinetic analysis showed a significant decrease in Vmax values, and an increase in K(m) values for MAO-B during treatment. 4. All seven drugs are competitive inhibitors of MAO-A, noncompetitive inhibitors of MAO-B, and were more potent in vitro for MAO-B. 5. MAO-A was inhibited by the following drugs (in ascending order of potency) : nortriptyline, amitriptyline, imipramine, maprotiline, zimeldine, nomifensine, and viloxazine. 6. MAO-B was inhibited by the following drugs (in ascending order of potency): nortriptyline, imipramine, maprotiline, amitriptyline, zimeldine, nomifensine, and viloxazine.

Cardiac microdialysis of salicylic acid to detect hydroxyl radical generation associated with sympathetic nerve stimulation

We examined the relationship between norepinephrine (NE) and hydroxyl free radical (OH) generation on cardiac nerve stimulation. Salicylic acid in Ringer's solution (0.5 nmol microliter-1 min-1) was infused directly through a microdialysis probe to detect the generation of hydroxyl radicals (OH) as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium of anesthetized rats. Sympathetic nerve stimulation increased the release of NE and the formation of DHBA. A positive linear correlation between the release of NE and the formation of 2,3-DHBA (R2 = 0.982) or 2,5-DHBA (R2 = 0.976) was observed. These data indicate that the sustained elevation of NE in the extracellular fluid can be auto-oxidized, which in turn leads (possibly by an indirect mechanism) to the formation of cytotoxic OH free radicals.

Senescence-accelerated mouse. Neurochemical studies on aging

Senescence-accelerated mouse (SAMP8) is known as a murine model of accelerated aging and memory dysfunction. The binding activity of [3H] 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxam ide (PK-11195) as a neurochemical marker of gliosis markedly increased with aging in the cerebral cortex and hippocampus of SAMP8. Immunoreactivity for glial fibrillary acidic protein (GFAP) was also enhanced. A beta-amyloid precursor protein (APP)-like immunoreactivity and 27-kDa-carboxyl terminal fragments of APP increased in SAMP8 brain. In addition, anti-APP antibody stained reactive astrocytes surrounding spongy degeneration in brain stern of SAMP8. These results suggest that astrocytosis and production of APP-derived fragments occur markedly in SAMP8 brains.

Isolation and characterization of cDNA and genomic clones encoding human muscle type carnitine palmitoyltransferase I

With a cDNA probe encoding rat muscle type carnitine palmitoyltransferase I (CPTI), we isolated cDNA and genomic clones encoding the human homologue and deduced the primary structure of human muscle type CPTI. By Northern analysis, we confirmed the dominant expression of this isoform in heart and skeletal muscle.

Role of adenosine in blood flow in the rat intestine

We examined the relation between adenosine production and increased blood flow. For this purpose, we used a sensor holding system with a laser Doppler blood flowmeter. The elevation of blood flow was observed by administration of adenosine. Therefore, when AMP was administered to the rats, the elevation of blood flow rate was observed. These results suggest that AMP is rapidly transported to the adenosine active site by ecto-5'-nucleotidase.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1994). III. Secular changes in susceptibility]

Susceptibilities of Enterococcus faecalis, Staphylococcus aureus, Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp., Proteus mirabilis, Pseudomonas aeruginosa and Serratia spp. isolated from patients with urinary tract infections (UTIs) in 10 hospitals during June 1994 to May 1995 to various antimicrobial agents were compared with those in the same period of previous years according to a classification, uncomplicated UTIs, complicated UTIs without indwelling catheter, and complicated UTIs with indwelling catheter. No remarkable changes were found in susceptibilities of Citrobacter spp., Enterobacter spp. and Serratia spp. The susceptibilities of E. faecalis to amikacin and quinolones were better than those in 1993. As for S. aureus, susceptible strains to all drugs increased in uncomplicated UTIs. Against E. coli in 1993, the antimicrobial activities of piperacillin, cefotiam and aminoglycosides have decreased, however, in 1994, these activities have turned to the better state. As for Klebsiella spp. susceptible strains to ABPC decreased. The susceptibilities of P. mirabilis to all drugs except minocycline were good. Against P. aeruginosa in 1993, the activities of aminoglycosides have decreased, but, in 1994, these activities have turned to the better state. These data should be considered in clinical treatment of various urinary tract infections.

Monoamine oxidase released into plasma treated with the hepatotoxin allyl formate

Monoamine oxidase (MAO) released from the rat liver into plasma and the activity levels of lipid peroxide (LPO) and superoxide dismutase (SOD) in liver tissue were investigated after pretreatment of rats with the perilobular hepatotoxin allyl formate (AF). When 3H-pargyline was given to AF-pretreated rats, the levels of 3H-pargyline labelled MAO in rat plasma were increased to 38% (p < 0.01 vs control), but the radioactivity was decreased to 35% (p < 0.05 vs control). The molecular weight of MAO subunits in plasma was similar to that of MAO subunits in liver (about 60,000) as determined by SDS electrophoresis. Liver tissue LPO levels in these rats were increased, whereas SOD activity was decreased. These results suggest that MAO in liver mitochondria was released into plasma as a consequence of membrane disorder.

Effect of iron (II) on the generation of hydroxyl free radicals in rat myocardium

We examined the effect of iron (II) on the generation of hydroxyl radicals (.OH) in the extracellular fluid of rat myocardium. Salicylic acid in Ringer's solution (0.5 nmole x microliter(-1) x min(-1)) was directly infused through a microdialysis probe to detect the generation of OH as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium. Iron clearly produced a dose-dependent increase in .OH formation. A positive linear correlation between iron (II) and the formation of 2,3-DHBA (R2 = 0.970) or 2.5-DHBA (R2 = 0.983) was observed. However, when desferrioxamine (DES) was infused through a dialysis probe, a marked increase in DHBA formation was obtained. The present results suggest that iron (III) may reduce .OH formation by the Fenton reaction.