Continuous monitoring of cellular nitric oxide generation by spin trapping with an iron-dithiocarbamate complex

Nitric oxide (NO) generation in murine macrophages was determined in real time using the electron paramagnetic resonance (EPR) spin trapping method. An iron complex of N-methyl D-glucamine dithiocarbamate was utilized as the spin trap. This spin trapping compound reacts with NO in solution to form a specific room-temperature stable, mononitrosyl complex which is readily detected and identified by EPR spectroscopy. Mouse peritoneal macrophages were placed in an EPR sample-cell and activated by lipopolysaccharide and gamma-interferon at 37 degrees C, followed by an additional incubation in oxygenated medium without these activation agents. After various incubation periods, spin trap solution was infused to replace the medium in the sample-cell, and the time-evolution of the EPR signal of the spin adduct (NO-complex) was recorded. Rates of NO generation were calculated based upon the initial slopes of the increase in the EPR intensity with time. In comparison to the NO (or NO2-) generation rate obtained under similar experimental conditions using the Griess reaction assay, the spin trapping method was found to be more sensitive, with a lowest limit of the detection of 3 pmol/min. In addition, by using the spin trapping method, NO generation from the same cells could be measured consecutively during various stages of activation, because infusion of the spin trap solution did not affect the viability of macrophages.

Hemostatic abnormalities and increased vascular endothelial cell markers in patients with red cell fragmentation syndrome induced by mitomycin C

We examined red cell fragmentation syndrome (RCFS) induced by mitomycin C (MMC) (13 patients), by thrombotic thrombocytopenic purpura (TTP) (17 patients), and by disseminated intravascular coagulation (DIC) (15 patients). Plasma cytokine levels were increased in the TTP and DIC patients, but not in those whose RCFS was induced by MMC, suggesting that the activation of the immune system plays an important role in the pathogenesis of RCFS due to TTP and DIC but did not in RCFS due to MMC. Plasma thrombomodulin, tissue type plasminogen activator, and plasminogen activator inhibitor-I levels were increased in all RCFS patients, suggesting that RCFS, whether MMC induced, or due to TTP or DIC, might be associated with vascular endothelial cell injury. In TTP, von Willebrand factor (vWF) antigen and high molecular weight vWF multimer levels were reduced, possibly as a result of microthrombus consumption. The hemostatic data in this study showed that the TTP patients were in a hypercoagulable state without hyperfibrinolysis, and that DIC patients were in both a hypercoagulable and a hyperfibrinolytic state, whereas hemostatic abnormalities were slight in patients with MMC induced RCFS. These findings suggest that vascular endothelial cell injuries might be associated with RCFS, and that those injuries in MMC-induced RCFS might not be related to microthrombi or an activated immune system.

[Myelofibrosis complicated by T-cell lymphoma followed by leukemic transformation]

A 37-year-old man was admitted because of pancytopenia with leukoerythroblastosis and anisocytosis in January 1986. Bone marrow aspiration resulted in a dry tap and biopsy showed marked myelofibrosis. Three months after admission, generalized lymph node swelling and multiple skin tumors were recognized. A biopsied lymph node revealed lymphoblastic lymphoma. The surface markers of lymphoma cells showed an immature T-cell phenotype, whereas T-cell receptor beta and gamma chain genes showed germ line configuration. The patient was treated with combination chemotherapy in June 1986. A month later, he developed leukemic transformation with features of acute myelocytic leukemia and he died of pneumonia. Autopsy disclosed extramedullary hematopoiesis in the liver and spleen. Primary myelofibrosis complicated by T-cell lymphoma is extremely rare.

Cardiac musculature of the cranial vena cava in the common tree shrew (Tupaia glis)

Cardiac musculature of the cranial vena cava in the common tree shrew (Tupaia glis) was examined by light and transmission electron microscopy. The common tree shrew has well developed cardiac myocyte layers in the tunica media of the cranial vena cava, extending from the right atrium to the root of the subclavian vein. Because the common tree shrew belongs to a primitive group of mammals, the occurrence of cardiac musculature in the cranial vena cava may be a common feature in lower mammals. The development of this musculature indicates that active contraction of the cranial vena cava wall occurs in this species. Electron micrographs showed the typical ultrastructure of myocytes and nerve endings. These observations suggest that this musculature may serve as a regulatory pump for the return of venous blood to the right atrium and as a blood reservoir system under conditions of rapid heart rate. Additionally, the presence of atrial natriuretic polypeptide (ANP) was also demonstrated in the myocytes of the vena cava immunohistochemically. These findings show that the cardiac endocrine organ for ANP develops even in the principal veins including the cranial vena cava.

Spin trapping isotopically-labelled nitric oxide produced from [15N]L-arginine and [17O]dioxygen by activated macrophages using a water soluble Fe(++)-dithiocarbamate spin trap

The unique capabilities of EPR spin trapping of nitric oxide based on a ferrous-dithiocarbamate spin trap have been demonstrated in a study verifying the source of the nitrogen and oxygen atoms in nitric oxide produced from activated macrophages. Spin trapping experiments were performed during nitric oxide generation from activated mouse peritoneal macrophages using the ferrous complex of N-methyl D-glucamine dithiocarbamate as a spin trap. When 15N-substituted arginine was given to the activated macrophages in the presence of the spin trap, a characteristic EPR spectrum of the nitric oxide spin adduct was obtained, which indicates the presence of the 15N atom in the nitric oxide molecule. The hyperfine splitting (hfs) constant of the 15N nucleus was 17.6 gauss. When 17O-containing dioxygen (55%) was supplied to the medium, an EPR spectrum consistent with the 17O-substituted nitric oxide spin adduct was observed in the composite spectrum. The hfs of 17O was estimated to be 2.5 gauss. The 14NO spin adduct observed after prolonged incubation in the medium which contains [15N]L-arginine as the only extracellular source of arginine demonstrates that arginine is recycled through its metabolite in activated macrophages.

[Acute promyelocytic leukemia following ulcerative colitis]

We report a case of acute promyelocytic leukemia (APL) following ulcerative colitis (UC). A 23-year-old man was diagnosed as UC in January 1991 and had been treated with salazosulfapyridine and prednisolone with good effect. In September 1993, he developed bleeding tendency and a diagnosis of APL with disseminated intravascular coagulation was made based on the results of bone marrow aspiration and coagulation profile. Complete remission was achieved with All-trans retinoic acid together with combined chemotherapy. He died of sepsis during consolidation chemotherapy in December 1993. Autopsy revealed no recurrence of UC.

Can spin trapping compounds like PBN protect against self-inflicted damage in polymorphonuclear leukocytes?

Polymorphonuclear leukocytes (PMNs) have been suggested to be damaged by superoxide radical generated on their own. The protective capacity of a spin trapping compound, phenyl-N-tert-butyl nitrone (PBN) was evaluated for this damage which occurs after the induction of superoxide generation. The life span of PMNs after superoxide generation was measured in the presence of PBN using the cell counting method, and effects of PBN on the amount of superoxide generated were quantitated using both cytochrome c reduction and spin trapping with DMPO. Results indicated significant extension of life span when PBN was present, and the extension was dose dependent. However, the magnitude of life span extension was not as large as expected from the decrease of superoxide generation. Possible mechanisms for the protection of PMNs by PBN are discussed.

Acute myelomonocytic leukemia in a patient with multiple myeloma: evidence for different clonal origin

A case of 77-year-old female with multiple myeloma (IgG-k) developed acute myelomonocytic leukemia (AMMoL) following a myelodysplastic stage after chemotherapy with melphalancyclophosphamide combinations for 6 years. The leukemic blast cells expressed both myeloid antigens (CD11b, CD13, CD14, CD15, CD33 and CD34) and T/B lymphoid antigens (CD2, CD4, CD22 and PCA1). Cytogenetic analysis revealed a chromosome deletion -7. Analysis of immunoglobulin genes showed the heavy chain genes in germ line configuration. These findings indicate that the AMMoL was a therapy-related stem cell leukemia and was a clonal origin genetically different from multiple myeloma irrespective of plasma cell phenotype.

The complete amino acid sequence of chitinase-B from the leaves of pokeweed (Phytolacca americana)

The complete amino acid sequence of pokeweed leaf chitinase-B (PLC-B) has been determined by first sequencing all 19 tryptic peptides derived from the reduced and S-carboxymethylated (RCm-) PLC-B and then connecting them by analyzing the chymotryptic peptides from three fragments produced by cyanogen bromide cleavage of RCm-PLC-B. PLC-B consists of 274 amino acid residues and has a molecular mass of 29,473 Da. Six cysteine residues are linked by disulfide bonds between Cys20 and Cys67, Cys50 and Cys57, and Cys159 and Cys188. From 58-68% sequence homology of PLC-B with five class III chitinases, it was concluded that PLC-B is a basic class III chitinase.

Decreased protein C inhibitor after percutaneous transluminal coronary angioplasty in patients with acute myocardial infarction

Plasma thrombin-antithrombin III complex (TAT), FDP-D-dimer, activated protein C (APC)-protein C inhibitor (PCI) complex, and tissue type plasminogen activator (t-PA), PA inhibitor-1 (PAI-I) were significantly increased in patients with acute myocardial infarction (AMI) at onset. These patients exhibited a hypercoagulable state and protein C activation at onset. The plasma PCI level at onset of AMI was within the normal range, but was significantly decreased after percutaneous transluminal coronary angioplasty (PTCA). After PTCA, plasma t-PA, FDP-D-dimer, and plasmin-alpha 2-plasmin inhibitor were increased but APC-PCI complex and TAT were not. The decrease in PCI after PTCA may have been caused by the activation of fibrinolysis. PCI may play an important role in the inhibition of fibrinolysis in stimulated or damaged endothelial cells. These findings suggest that the protein C pathway plays an important role in the onset of AMI and after PTCA.

Mutual contact of adherent polymorphonuclear leukocytes inhibits their generation of superoxide

Superoxide generation by polymorphonuclear leukocytes (PMNs) in suspension, or adherent to glass or plastic, after stimulation with N-formylmethionyl-leucyl-phenylalanine or phorbol myristate acetate was measured by cytochrome c reduction and spin trapping. Amounts of superoxide generated by adherent PMNs were inversely related to cell density. The generation of hydrogen peroxide was also inhibited at higher cell densities. In contrast to adherent cells, superoxide released by PMNs in suspension linearly increased with respect to cell number over a wider range. Microscopic observation indicated that the number of cells in mutual contact increased rapidly at cell densities higher than 4 x 10(4) cells/cm2, and inhibition of superoxide became apparent at higher cell densities. Mediators which could be released by PMNs, such as NO and adenosine, were not the cause of inhibition. These data suggest that mutual contact of PMNs suppresses their generation of superoxide. Survival rates of PMNs after stimulation increased at higher densities, indicating that the mutual contact-induced inhibition of superoxide generation by PMNs may be physiologically relevant at sites of inflammation.

Clearance and distribution of a haemorrhagic factor purified from Bothrops jararaca venom in mice

We previously purified two fibrinolytic/haemorrhagic enzymes (jararafibrase-I and II) from Bothrops jararaca venom. In the present study, the clearance, organ distribution and local absorption rate were examined in mice using 125I-labelled jararafibrase-I. Following intravenous injection of 125I-labelled jararafibrase-I, a complex was rapidly formed with the plasma protein and the radioactivity quickly disappeared from the circulation with a half-life of about 3 min for the initial part of the curve. The highest level of the radioactivity (59.5%) was seen in the liver at 5 min after dosing, and the next highest level of radioactivity (14.4%) was seen in the kidney at 60 min after dosing. At 60 min after dosing, 36.8% of the total injected radioactivity was seen in the contents of the small intestine, and 11.4% of the total injected radioactivity was seen in the contents of the large intestine at 120 min after dosing. It is assumed that the jararafibrase-I was metabolized mainly in the liver, to small mol. wt products, and excreted in the intestine via the bile duct. Also, a small amount of jararafibrase-I appeared to be metabolized in the kidney. Following subcutaneous injection, a high-dose group revealed a low local absorption rate. The low local absorption rate was apparently due to a diminished blood flow caused by subcutaneous haemorrhage.

Quadruple cancers in a human T-cell leukemia virus type 1 carrier

Human T-cell leukemia virus type 1 (HTLV-1) infection is considered to contribute to the risk of malignancies other than adult T-cell leukemia. We report a 64-year-old male HTLV-1 carrier who developed quadruple malignancies such as cancer of the urinary bladder, skin, larynx and liver.

[Experience with atrioventricular valve replacement in infants and children]

From 1980 to 1989, nine infants and children underwent valve replacement. These replacements consisted of seven mitral valve replacement (MVR), one left atrioventricular valve replacement, and one aortic valve (AVR) replacement. We excluded AVR from this report. Follow-up period of 8 cases were 68 months in an average. During this period, 2 cases were not thought to be satisfactory as antithrombotic therapy, in which one revealed malfunctioning prosthesis, and secondary MVR implantation was performed. Another one is free from any complications. We experienced the difficulty of antithrombotic therapy following valve replacement in infants and children. It is supposed that combined use of anticoagulant therapy agent and antiplatelet agent may be necessary as antithrombotic therapy, especially in childhood.

Increased activated protein C-protein C inhibitor complex levels in patients with pulmonary embolism

Activated protein C (APC)-protein C inhibitor (PCI) complex level was examined in 35 patients with acute pulmonary embolism (PE) and in 20 healthy volunteers. Thrombin-antithrombin III complex, plasmin alpha 2 plasmin inhibitor complex, and fibrin-D-dimer levels were significantly increased in the patients with PE compared to levels in healthy volunteers. Levels of plasminogen activator inhibitor-I, tissue type plasminogen activator, and von Willebrand factor antigens were also significantly increased in patients with PE. Plasma level of APC-PCI complex was increased in most patients with PE and APC-alpha 1 antitrypsin complex level was increased in 13 patients. These complexes were not detected in healthy volunteers. These findings suggested that plasma protein C was activated in patients with PE, and that PCI was the major inhibitor of APC generated in this condition. Thus, regulation of the protein C pathway might play an important role in the pathogenesis of PE.

Mechanism of the suppression of repetitive atrial firing by isoproterenol--comparison with disopyramide

To investigate whether isoproterenol (Iso) could suppress the initiation of repetitive atrial firing (RAF), we investigated its effect on RAF in comparison with that of disopyramide (Diso). Extrastimuli at a basic cycle length of 500 ms were delivered from the high right atrium in 49 patients who received an intravenous infusion of Iso (0.01 microgram/kg per min) and in 39 patients given intravenous Diso (2 mg/kg per 10 min). Induction of RAF, the atrial effective refractory period (A-ERP), and the maximum conduction delay (MCD) were measured. Iso abolished the induction of RAF in 13/19 (68%) patients, while Diso did so in 13/22 (59%) patients. Thirty-four of the 41 patients with RAF in the baseline study had an A-ERP < 250 ms and an MCD > 40 ms. Iso significantly decreased the A-ERP from 205 +/- 26 to 194 +/- 23 ms (P < 0.01) and significantly decreased the MCD from 67 +/- 24 to 39 +/- 16 ms (P < 0.0001) in 19 patients with RAF. On the other hand, Diso significantly increased the A-ERP from 203 +/- 31 to 235 +/- 36 ms (P < 0.0001), and significantly diminished the MCD from 68 +/- 31 to 55 +/- 30 ms (P < 0.01) in 22 patients with RAF. In patients with new RAF (n = 7) or re-induced RAF (n = 14) during Iso or after Diso, the MCD was more than 40 ms. Our results suggest that there are two different modes of RAF suppression, i.e. shortening or lengthening of the A-ERP.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intravenous verapamil on atrial vulnerability

To investigate the effects of verapamil on indicators of atrial vulnerability, we examined 30 patients with paroxysmal supraventricular tachycardia who received intravenous verapamil during an electrophysiologic study. Single atrial extrastimuli were given before and after intravenous administration of verapamil to induce repetitive atrial firing (RAF) or atrial fibrillation, and to examine the maximum A2/A1, which was defined as the maximum ratio of the duration of the atrial electrogram resulting from premature stimulation (A2) to that resulting from the basic drive beat (A1). The maximum A2/A1 increased from 145 +/- 20% to 154 +/- 25% (p < 0.02) after verapamil administration. The maximum A2/A1 in patients in whom neither RAF nor atrial fibrillation were induced both before and after verapamil were smaller than those in patients in whom RAF was induced only after verapamil (before; 138 +/- 20% vs 165 +/- 15%, p < 0.02. after; 144 +/- 22% vs 172 +/- 17%, p < 0.05). RAF or atrial fibrillation was induced only after verapamil in 6 patients, who showed a maximum A2/A1 before verapamil of 150% or more. These data suggest that verapamil may induce repetitive atrial firing and possibly atrial fibrillation in some predisposed patients, especially in those that have a greater maximum A2/A1, which may be an indicator of local intraatrial conduction delay before drug infusion.

A case of myelodysplastic syndrome progressing to acute myelocytic leukemia in which adult-onset Still's disease had occurred 6 years before

A patient with adult-onset Still's disease who presented with myelodysplastic syndrome (MDS) after a course of 6 years is reported. To our knowledge, this is the first such reported case. The patient died of acute myelocytic leukemia. The possibility that cyclosporine contributed to the onset of MDS is discussed.

Elevated plasma levels of vascular endothelial cell markers in patients with hypercholesterolemia

Hypercholesterolemia is associated with an increased incidence of vascular complications. To assess the actual degree of activation of coagulation systems and vascular disorders in hypercholesterolemia, plasma levels of vascular endothelial cell markers, such as thrombomodulin (TM), tissue-type plasminogen activator, plasminogen activator inhibitor-I (PAI-I), and von Willebrand factor, were measured in 51 patients with hypercholesterolemia. We also investigated the effects of Pravastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on plasma lipid, lipoprotein a, and hemostatic markers. The mean plasma levels of thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA), TM, and PAI-I were significantly elevated in hypercholesterolemia. Of the hemostatic markers, only TM was significantly increased in patients with ischemic heart diseases (IHD). The mean concentration of total cholesterol and levels of TAT, FPA, PAI-I, and TM were significantly reduced after the Pravastatin treatment. The PIC/TAT ratio was significantly increased in non-IHD patients after treatment, this was not the case in IHD patients. These findings suggested the presence of a thrombogenic state and vascular endothelial cell disorders in hypercholesterolemia; such a state might well be related to hypofibrinolysis.

Relationship between atrial conduction defects and fractionated atrial endocardial electrograms in patients with sick sinus syndrome

The relationship between abnormal atrial electrograms (AAE) recorded during sinus rhythm by endocardial catheter mapping of the right atrium and the atrial conduction defects of sinus impulses or single atrial extrastimuli was investigated in 44 patients with sick sinus syndrome. The patients were divided into two groups on the basis of the presence (n = 29) or absence (n = 15) of AAE recorded during sinus rhythm. The P wave duration in the AAE (+) Group patients was 137 +/- 14 msec, and 125 +/- 15 msec in the AAE (-) Group; P < 0.02. The intraatrial conduction time of sinus impulses in the AAE (+) Group was 54 +/- 12 msec, and 39 +/- 9 msec in the AAE (-) Group; P < 0.001. The interatrial conduction time in the AAE (+) Group was 101 +/- 14 msec, and 78 +/- 16 msec in the AAE (-) Group; P < 0.001. In the AAE (+) Group, 11 (38%) patients had a sinus node recovery time > 4 seconds, whereas in the AAE (-) Group there was only one (6%) patient; P < 0.03. AAE showed a specificity of 93% and a positive predictive accuracy of 91% in predicting inducibility of atrial fibrillation. The sensitivity was 35% and the negative predictive accuracy was 42%. Sustained atrial fibrillation was induced in ten (35%) patients of the AAE (+) Group, and in one (7%) patient of the AAE (-) Group; P < 0.05. These data suggest that in patients with sick sinus syndrome who possess abnormal endocardial electrograms in sinus rhythm within the right atrium have: (1) a significantly longer P wave duration; (2) a significantly longer intraatrial and interatrial conduction time of sinus impulses; and (3) a significantly greater sinus node dysfunction and higher incidence of induction of sustained atrial fibrillation. It is concluded that there are significantly greater atrial conduction defects in patients with sick sinus syndrome who possess AAE within the right atrium during sinus rhythm.

Increased levels of vascular endothelial cell markers in thrombotic thrombocytopenic purpura

We found that patients with thrombotic thrombocytopenic purpura (TTP) have significantly elevated plasma thrombin antithrombin III complex (TAT) and FDP-D-dimer levels, while the plasmin-alpha 2 plasmin inhibitor complex (PIC) level was only slightly increased. The tissue-type plasminogen activator (t-PA) level was increased, but it was well correlated with the plasminogen activator inhibitor-I (PAI-I) level. These findings suggest that hypercoagulable and hypofibrinolytic states coexist in these patients, in contrast to patients with disseminated intravascular coagulation, who exhibit coexisting hypercoagulable and hyperfibrinolytic states. Levels of vascular endothelial cell markers, such as PAI-I, thrombomodulin (TM), and t-PA, were increased at the onset of TTP, but the level of von Willebrand factor (vWF) antigen was not increased. The outcome in TTP patients was correlated with plasma t-PA and TM levels but not with TAT or PIC. These results suggest that vascular endothelial cell markers, such as TM and t-PA, are released from injured or stimulated endothelial cells, reflecting the degree of vascular endothelial damage, and that the main factor in the pathogenesis of TTP is vascular endothelial cell injury.

Increased plasma level of interleukin-6 in disseminated intravascular coagulation

Plasma interleukin-6 (IL-6) was higher in patients with disseminated intravascular coagulation (DIC) than in those without DIC. Levels of IL-1 beta and TNF alpha were also significantly higher in patients with DIC. Plasma IL-6 was highest in patients with underlying sepsis and was also high in those with advanced solid cancer. Levels were high in some patients with acute promyelocytic leukaemia and were significantly higher in patients with organ failure than in those without this complication. Plasma IL-6 was higher in DIC patients showing a poor response to therapy than in those with a good response. Incubation with IL-6 caused significant increases in tissue factor activity in mononuclear cells and release of plasminogen activator-1 antigen from human umbilical vein endothelial cells. As increases in IL-6 might give rise to hypercoagulable and hypofibrinolytic states, this may be a cause of DIC and be related to prognosis and organ failure.