Characterization of missense mutations in the NADPH oxidase partner p22phox in the A22° subtype of chronic granulomatous disease

Defective superoxide production by NADPH oxidase 2 (Nox2) in phagocyte cells results in the development of chronic granulomatous disease (CGD), a hereditary disease characterized by recurrent and life-threatening infections. The partner protein p22^phox is a membrane-spanning protein which forms a stable heterodimer with Nox2 in the endoplasmic reticulum. This interaction ensures the stability of each protein and their accurate trafficking to the cell membrane. The present paper describes the characterization of p22^phox missense mutations that were identified in a patient with CGD who presented with undetectable levels of p22^phox . Using a reconstitution system, it was found that p22^phox expression decreased when R90Q, A117E, S118R, A124S, A124V, A125T, or E129K mutations were introduced, suggesting that these mutations destabilize the protein. In contrast, introducing an L105R mutation did not affect protein expression, but did inhibit p22^phox binding to Nox2. Thus, the missense mutations discussed here contribute to the development of CGD by either disrupting protein stability or by impairing the interaction between p22^phox and Nox2.

Regulation of Derlin-1-mediated degradation of NADPH oxidase partner p22phox by thiol modification

The transmembrane protein p22^phox heterodimerizes with NADPH oxidase (Nox) 1–4 and is essential for the reactive oxygen species-producing capacity of oxidases. Missense mutations in the p22^phox gene prevent the formation of phagocytic Nox2-based oxidase, which contributes to host defense. This results in chronic granulomatous disease (CGD), a severe primary immunodeficiency syndrome. In this study, we characterized missense mutations in p22^phox (L51Q, L52P, E53V, and P55R) in the A22° type (wherein the p22^phox protein is undetectable) of CGD. We demonstrated that these substitutions enhanced the degradation of the p22^phox protein in the endoplasmic reticulum (ER) and the binding of p22^phox to Derlin-1, a key component of ER-associated degradation (ERAD). Therefore, the L⁵¹-L⁵²-E⁵³-P⁵⁵ sequence is responsible for protein stability in the ER. We observed that the oxidation of the thiol group of Cys-50, which is adjacent to the L⁵¹-L⁵²-E⁵³-P⁵⁵ sequence, suppressed p22^phox degradation. However, the suppression effect was markedly attenuated by the serine substitution of Cys-50. Blocking the free thiol of Cys-50 by alkylation or C50S substitution promoted the association of p22^phox with Derlin-1. Derlin-1 depletion partially suppressed the degradation of p22^phox mutant proteins. Furthermore, heterodimerization with p22^phox (C50S) induced rapid degradation of not only Nox2 but also nonphagocytic Nox4 protein, which is responsible for redox signaling. Thus, the redox-sensitive Cys-50 appears to determine whether p22^phox becomes a target for degradation by the ERAD system through its interaction with Derlin-1.

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Missense mutations in exon 3 of p22^phox enhance the binding of p22^phox to Derlin-1.

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Oxidation of the thiol group of p22^phox Cys50 suppresses p22^phox degradation.

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Serine substitution of Cys-50 increases the affinity of p22^phox for Derlin-1.

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Stability of the p22^phox protein is regulated by redox-sensitive Cys-50.

The downregulation of NADPH oxidase Nox4 during hypoxia in hemangioendothelioma cells: a possible role of p22phox on Nox4 protein stability

NADPH oxidase (Nox) 4 produces H₂O₂ by forming a heterodimer with p22^phox and is involved in hemangioendothelioma development through monocyte chemoattractant protein-1 (MCP-1) upregulation. Here, we show that Nox4 protein levels were maintained by p22^phox in hemangioendothelioma cells and Nox4 protein stability was dependent on p22^phox coexpression. Conversely, the degradation of Nox4 monomer was enhanced by p22^phox knockdown. Under hypoxic conditions in hemangioendothelioma cells, p22^phox was downregulated at the mRNA and protein levels. Downregulation of p22^phox protein resulted in the enhanced degradation of Nox4 protein in hypoxia-treated hemangioendothelioma cells. In contrast, Nox2, a Nox isoform, was not altered at the protein level under hypoxic conditions. Nox2 exhibited a higher affinity for p22^phox compared with Nox4, suggesting that when coexpressed with Nox4 in the same cells, Nox2 acts as a competitor. Nox2 knockdown restored Nox4 protein levels partially reduced by hypoxic treatment. Thus, Nox4 protein levels were attenuated in hypoxia-treated cells resulting from p22^phox depletion. MCP-1 secretion was decreased concurrently with hypoxia-induced Nox4 downregulation compared with that under normoxia.

Coculture in vitro with endothelial cells induces cytarabine resistance of acute myeloid leukemia cells in a VEGF-A/VEGFR-2 signaling-independent manner

An interaction between acute myeloid leukemia (AML) cells and endothelial cells in the bone marrow seems to play a critical role in chemosensitivity on leukemia treatment. The endothelial niche reportedly enhances the paracrine action of the soluble secretory proteins responsible for chemoresistance in a vascular endothelial growth factor A (VEGF-A)/VEGF receptor 2 (VEGFR-2) signaling pathway-dependent manner. To further investigate the contribution of VEGF-A/VEGFR-2 signaling to the chemoresistance of AML cells, a biochemical assay system in which the AML cells were cocultured with human endothelial EA.hy926 cells in a monolayer was developed. By coculture with EA.hy926 cells, this study revealed that the AML cells resisted apoptosis induced by the anticancer drug cytarabine. SU4312, a VEGFR-2 inhibitor, attenuated VEGFR-2 phosphorylation and VEGF-A/VEGFR-2 signaling-dependent endothelial cell migration; thus, this inhibitor was observed to block VEGF-A/VEGFR-2 signaling. Interestingly, this inhibitor did not reverse the chemoresistance. When VEGFR-2 was knocked out in EA.hy926 cells using the CRISPR-Cas9 system, the cytarabine-induced apoptosis of AML cells did not significantly change compared with that of wild-type cells. Thus, coculture-induced chemoresistance appears to be independent of VEGF-A/VEGFR-2 signaling. When the transwell, a coculturing device, separated the AML cells from the EA.hy926 cells in a monolayer, the coculture-induced chemoresistance was inhibited. Given that the migration of VEGF-A/VEGFR-2 signaling-dependent endothelial cells is necessary for the endothelial niche formation in the bone marrow, VEGF-A/VEGFR-2 signaling contributes to chemoresistance by mediating the niche formation process, but not to the chemoresistance of AML cells in the niche.

Constitutive activity of NADPH oxidase 1 (Nox1) that promotes its own activity suppresses the colon epithelial cell migration

Superoxide producing NADPH oxidase 1 (Nox1), abundantly expressed in the colon epithelium, plays a crucial role in mucosal host defenses. In this study, we found that pre-treatment of cells with edaravone, a free radical scavenger, inhibited Nox1 constitutive activity even after washout without affecting Nox1 trafficking to the plasma membrane and membrane recruitment of the cytosolic regulators Noxo1 and Noxa1. These results suggest that a Nox1-derived product is involved in the step that initiates the electron transfer reaction after the formation of the Nox1-Noxo1-Noxa1 complex. Furthermore, we show that the mean migration directionality and velocity of epithelial cells were significantly enhanced by the inhibition of constitutive Nox1 activity. Thus, the constitutive Nox1 activity limits undesired cell migration in resting cells while participating in a positive feedback loop toward its own oxidase activity.

The NADPH oxidase NOX4 promotes the directed migration of endothelial cells by stabilizing vascular endothelial growth factor receptor 2 protein

Directed migration of endothelial cells (ECs) is an important process during both physiological and pathological angiogenesis. The binding of vascular endothelial growth factor (VEGF) to VEGF receptor-2 (VEGFR-2) on the EC surface is necessary for directed migration of these cells. Here, we used TAXIScan, an optically accessible real-time horizontal cell dynamics assay approach, and demonstrate that reactive oxygen species (ROS)-producing NADPH oxidase 4 (NOX4), which is abundantly expressed in ECs, mediates VEGF/VEGFR-2-dependent directed migration. We noted that a continuous supply of endoplasmic reticulum (ER)-retained VEGFR-2 to the plasma membrane is required to maintain VEGFR-2 at the cell surface. siRNA-mediated NOX4 silencing decreased the ER-retained form of VEGFR-2, resulting in decreased cell surface expression levels of the receptor. We also found that ER-localized NOX4 interacts with ER-retained VEGFR-2 and thereby stabilizes this ER-retained form at the protein level in the ER. We conclude that NOX4 contributes to the directed migration of ECs by maintaining VEGFR-2 levels at their surface.

Magnetoliposomes as model for signal transmission

Liposomes containing magnetic nanoparticles (magnetoliposomes) have been extensively explored for targeted drug delivery. However, the magnetic effect of nanoparticles movement is also an attractive choice for the conduction of signals in communication systems at the nanoscale level because of the simple manipulation and efficient control. Here, we propose a model for the transmission of electrical and luminous signals taking advantage of magnetophoresis. The study involved three steps. Firstly, magnetite was synthesized and incorporated into fusogenic large unilamellar vesicles (LUVs) previously associated with a fluorescent label. Secondly, the fluorescent magnetite-containing LUVs delivered their contents to the giant unilamellar vesicles (GUVs), which were corroborated by magnetophoresis and fluorescence microscopy. In the third step, magnetophoresis of magnetic vesicles was used for the conduction of the luminous signal from a capillary to an optical fibre connected to a fluorescence detector. Also, the magnetophoresis effects on subsequent transmission of the electrochemical signal were demonstrated using magnetite associated with CTAB micelles modified with ferrocene. We glimpse that these magnetic supramolecular systems can be applied in micro- and nanoscale communication systems.

Monoclonal antibody 7D5 recognizes the R147 epitope on the gp91phox , phagocyte flavocytochrome b558 large subunit

Human phagocyte flavocytochrome b₅₅₈ (Cyt b), the catalytic center of nicotinamide adenine dinucleotide phosphate oxidase, consists of a heavily glycosylated large subunit (gp91^phox ; Nox2) and a small subunit (p22^phox ). Cyt b is a membrane-spanning complex enzyme. Chronic granulomatous disease (CGD) is predominantly caused by a mutation in the CYBB gene encoding gp91^phox on the X-chromosome. Because the phagocytes of patients with CGD are not able to generate the superoxide anion, these patients are susceptible to severe infections that can be fatal. It has been suggested that the extracellular region of gp91^phox is necessary for and critical to forming the epitope of mAb 7D5 and that 7D5 provides a useful tool for rapid screening of X-linked CGD by FACS. To further elucidate the mAb 7D5 epitope on human gp91^phox , chimeric DNA expressed human and mouse gp91^phox recombinant protein were constructed. The fusion proteins were immunostained for mAb 7D5 and analyzed by FACS and western blot analysis. The ¹⁴³ ELGDRQNES¹⁵¹ region was found to reside at the extracellular surface on human gp91^phox and to be an important epitope for the interaction with mAb 7D5, as analyzed by FACS analysis. In particular, amino acid R147 is a unique epitope on the membrane-associated Cyt b for mAb 7D5. In conclusion, it is proposed that FACS analysis using mAb 7D5 is a valuable tool for early diagnosis of CGD.

Histone acetyltransferase p300/CBP-associated factor is an effective suppressor of secretory immunoglobulin synthesis in immature B cells

The histone acetyltransferase p300/CBP-associated factor (PCAF) catalyzes acetylation of core histones and plays important roles in epigenetics by altering the chromatin structure in vertebrates. In this study, PCAF-deficient DT40 mutants were analyzed and it was found that PCAF participates in regulation of secretory IgM heavy chain (H-chain) synthesis. Remarkably, PCAF-deficiency causes an increase in the amount of secretory IgM H-chain mRNA, but not in that of IgM light chain and membrane-bound IgM H-chain mRNAs, resulting in dramatic up-regulation of the amount of secretory IgM protein. These findings suggest that PCAF regulates soluble antibody production and is thus an effective suppressor of secretory IgM H-chain synthesis.

A novel mutation of human liver alanine:glyoxylate aminotransferase causes primary hyperoxaluria type 1: immunohistochemical quantification and subcellular distribution

A novel alanine:glyoxylate aminotransferase (AGT) mutation involved in primary hyperoxaluria type 1 (PH1) was studied in Japanese patients. Two mutations in exon 7, c.751T>A and c.752G>A, lead to a W251K amino acid substitution. Proband 1 (patient 1) was homozygous for the W251K mutation allele (DDBJ Accession No. AB292648), and AGT-specific activity in the patient’s liver was very low. To reveal the cause of the low enzymatic activity, the intracellular localization of AGT (W251K) was studied using immunohistochemistry and immunoelectron microscopy. The latter analysis showed that patient 2 had only one-fifth of the normal AGT expression per catalase, suggesting impairment of AGT (W251K) dependent transport into peroxisomes. Peroxisomal transport of human AGT is believed to be dependent on the presence of the type 1 peroxisomal targeting sequence. The C-terminal tripeptide of AGT, KKL is necessary for peroxisomal targeting. In cultured cells, EGFP-AGT (W251K) localized both in the peroxisome and cytosol. These results were consistent with the data obtained from liver analysis of patient 2. The subcellular distribution of AGT (W251K) and the results from a random mutagenesis study suggest that KKL is necessary for peroxisomal targeting of human AGT, but additional signal other than KKL may be necessary.

A highly sensitive chemiluminescence assay for superoxide detection and chronic granulomatous disease diagnosis

Reactive oxygen species (ROS) produced by neutrophils are crucial for defense against infectious diseases, and the adequate measurement of ROS levels is an important way to evaluate the possibility of infections. The fluorescent probe dihydrorhodamine 123 has been applied exclusively to the measurement of ROS thus far. We developed a novel method for detecting ROS, which utilizes the chemiluminescent probes Luminol and Diogenes. The new method quantitatively detects ROS produced by as few as 10 to 10(4) neutrophils. Furthermore, this method can detect ROS levels in one microliter of whole blood or ROS produced by Epstein-Barr immortalized B lymphocytes. This method will be valuable for prompt diagnosis of neonatal chronic granulomatous diseases in which neutrophils aberrantly produce superoxide.

First experience with direct, selective factor Xa inhibition in patients with non-ST-elevation acute coronary syndromes: results of the XaNADU-ACS Trial

BACKGROUND

Unfractionated heparin is widely used in patients with non-ST-elevation acute coronary syndromes but has important limitations. Anticoagulants with predictable kinetics and anticoagulant effects, better efficacy, and greater safety are needed.

OBJECTIVE

To investigate the efficacy and safety of a direct, selective factor Xa inhibitor, DX-9065a (Daiichi Pharmaceuticals LTD, Inc.) compared with heparin, in patients with non-ST-elevation acute coronary syndromes.

PATIENTS AND METHODS

Patients (n = 402) from the USA, Canada, and Japan were randomized to blinded, weight-adjusted heparin, low-dose DX-9065a, or high-dose DX-9065a.

RESULTS

The primary efficacy endpoint of death, myocardial infarction, urgent revascularization, or ischemia on continuous ST-segment monitoring occurred in 33.6%, 34.3%, and 31.3% of patients assigned to heparin, low-dose DX-9065a, and high-dose DX-9065a (P = 0.91 for heparin vs. combined DX-9065a). The composite of death, myocardial infarction, or urgent revascularization occurred in 19.5%, 19.3%, and 11.9% (P = 0.125 for heparin vs. high-dose DX-9065a) of patients; major or minor bleeding occurred in 7.7%, 4.2%, and 7.0% of patients; and major bleeding in 3.3%, 0.8%, and 0.9% of patients. Higher concentrations of DX-9065a were associated with a lower likelihood of ischemic events (P = 0.03) and a non-significant tendency toward a higher likelihood of major bleeding (P = 0.32).

CONCLUSIONS

In this small phase II trial, there was a non-significant tendency toward a reduction in ischemic events and bleeding with DX-9065a compared with heparin in patients with acute coronary syndromes. The absence of an effect on ST-monitor ischemia warrants further investigation. These data provide the rationale for adequately powered studies of DX-9065a in acute coronary syndromes or percutaneous intervention.

Peroxisomes exist in growth cones and move anterogradely and retrogradely in neurites of PC12D cells

Localization and movement of peroxisomes have been investigated in neurites of a subline of PC12 pheochromocytoma cells (PC12D cells). The cells were transfected with a construct encoding the green fluorescent protein and bearing the C-terminal peroxisomal targeting signal 1 SKL motif (-Ser-Lys-Leu-COOH). Peroxisomes were detected as green punctate fluorescent signals. Many peroxisomes were observed in neurites of PC12D cells, especially in neural terminal-like structures, growth cones, varicosities, and branch points. Growth cones containing many peroxisomes were active, since they extended several long filopodias. Existence of peroxisomes in growth cones and neuronal terminal-like structures suggests that peroxisomes might have some role in neuronal extension and nerve terminal functioning. Peroxisomal motility was analyzed by time-lapse imaging using a fluorescence microscope at 25 degrees C. Peroxisomes were transported bidirectionally in neurites, i.e., through anterograde and retrograde transport. This result suggests that peroxisomes move to growth cones and neural terminals from the PC12D cell body, play some role in these parts, and go back to cell body.

Heart disease in Friedreich's ataxia: observation of a case for half a century

A case of Friedreich's ataxia was followed for 47 years, beginning in 1930; this patient had an abnormal electrocardiogram (flat or inverted T waves in leads II and III with prolonged QT interval) from the very beginning of the onset of neurological symptoms. Cardiac and neurological disturbances progressed slowly but steadily, and the patient died suddenly at the age of 67. The autopsy revealed typical findings of Friedreich's ataxia and hypertrophic cardiomyopathy with thickened left ventricular wall and myocardial fiber disarray. To the authors' knowledge, this is the longest continuous follow-up study of Friedreich's ataxia, and it will provide invaluable information on the natural history and development of the cardiac and neurological disorders in this condition.

Ethnicity and long-term outcome after an acute coronary event. Multicenter Myocardial Ischemia Research Group

BACKGROUND

The role of ethnicity on the long-term outcome after myocardial infarction is not fully understood.

METHODS AND RESULTS

We analyzed the data from the Multicenter Study of Myocardial Ischemia in North America and Japan. We enrolled patients after acute myocardial infarction (MI) or unstable angina, with follow-up for 6 to 43 months, an average of 26 months. Among patients enrolled, there were 627 white, 158 black, and 109 Asian patients. Unadjusted cardiac events (cardiac death or nonfatal MI) were more frequent in black patients than in the other 2 ethnic groups (12% in blacks, 6. 4% in whites, 4.0% in Asians, P =.022). Although insulin-dependent diabetes, history of hypertension, and female sex were most frequent in black subjects, coronary angioplasty and thrombolysis at index event were done equally. After adjusting for several covariates, Cox analyses revealed that the black group was significantly associated with cardiac events (hazard ratio 6.5, P =.002). Subgroup analyses showed that the event rate among patients who had a higher educational level (6.1% in whites, 5.9% in blacks, and 7.0% in Asian, P =.94) or who were in a professional occupational class (5.7% in whites, 4.0% in blacks, and 4.8% in Asians, P = 1.0) was not different among the 3 ethnic groups.

CONCLUSIONS

Blacks have an increased rate of cardiac events after MI, and a lower socioeconomic status may contribute to the adverse outcome in this ethnic group.

Long-term nitrate use may be deleterious in ischemic heart disease: A study using the databases from two large-scale postinfarction studies. Multicenter Myocardial Ischemia Research Group

BACKGROUND

Secondary coronary prevention studies have generally focused on specific medications, often to the exclusion of commonly used therapies. To date, long-term nitrate use has not been investigated in large-scale clinical trials.

METHODS AND RESULTS

We examined the relation between long-acting nitrates given during the chronic phase of the disease and the outcome. We analyzed data prospectively acquired in a large, observational study involving 1042 patients enrolled for the Multicenter Study of Myocardial Ischemia (MSMI) in North America, Israel, and Japan as well as 1779 patients enrolled for the Multicenter Diltiazem Post Infarction Trial (MDPIT). The Cox analyses with all the variables retained revealed that nitrates were associated with a significantly increased mortality risk (MSMI: hazard ratio 3.78, P =.011; MDPIT: hazard ratio 1.61, P =.019) in patients who had recovered from an acute coronary event. The analyses with the propensity score method on the MSMI and the MSMI databases also showed that the risk for cardiac death with use of nitrates was increased in most of the 5 subclasses according to the score.

CONCLUSION

These analyses raise concern about the potential adverse effects of long-acting nitrate therapy in chronic coronary disease.

From myocarditis to cardiomyopathy: mechanisms of inflammation and cell death: learning from the past for the future

A progression from viral myocarditis to dilated cardiomyopathy has long been hypothesized, but the actual extent of this progression has been uncertain. However, a causal link between viral myocarditis and dilated cardiomyopathy has become more evident than before with the tremendous developments in the molecular analyses of autopsy and endomyocardial biopsy specimens, new techniques of viral gene amplification, and modern immunology. The persistence of viral RNA in the myocardium beyond 90 days after inoculation, confirmed by the method of polymerase chain reaction, has given us new insights into the pathogenesis of dilated cardiomyopathy. Moreover, new knowledge of T-cell-mediated immune responses in murine viral myocarditis has contributed a great deal to the understanding of the mechanisms of ongoing disease processes. Apoptotic cell death may provide the third concept to explain the pathogenesis of dilated cardiomyopathy, in addition to persistent viral RNA in the heart tissue and an immune system-mediated mechanism. Beneficial effects of alpha1-adrenergic blocking agents, carteolol, verapamil, and ACE inhibitors have been shown clinically and experimentally in the treatment of viral myocarditis and dilated cardiomyopathy. Antiviral agents should be more extensively investigated for clinical use. The rather discouraging results obtained to date with immunosuppressive agents in the treatment of viral myocarditis indicated the importance of sparing neutralizing antibody production, which may be controlled by B cells, and raised the possibility of promising developments in immunomodulating therapy.

Mesangiolytic glomerulopathy in severe congestive heart failure

To study the glomerular morphological abnormalities in congestive heart failure (CHF), we analyzed 27 autopsy cases without other causes of renal disease. Their mean age was 59 years, and they showed mild prerenal azotemia. They had generally been treated with digitalis and diuretics, and a few of them with captopril or nifedipine. The abnormal glomerular findings of enlargement, hyperemia, and mesangial thickening were observed at high frequencies (61%, 64%, and 57%, respectively). They characteristically showed mesangiolysis (ML) by the findings of microaneurysms (81%) and mesangial degeneration (70%) such as loose reticular matrix and poor matrix area. In addition, glomerular infiltration of mononuclear leukocytes including macrophages was noted in 70% of the cases. Glomerular enlargement was not correlated with the grade of hyperemia, but it was correlated with the grade of ML index of % glomeruli with microaneurysms (F = 7.22, p < 0.004). There was an inverse relationship between the grades of mesangial thickening and of the ML index (P < 0.005). The number of glomerular leukocytes was positively correlated with mean glomerular size (P < 0.002) and with the ML index (P < 0.03). Notably, the glomerular macrophage-positive cases showed a prominently higher mean ML index than the negative cases (P < 0.005). There was an inverse correlation between the mean glomerular size and the partial oxygen pressure in arterial blood (PaO2; P < 0.01), and a positive correlation between the mean glomerular size and hematocrit (Hct) levels (P < 0.02). The cases positive for mesangiolytic mesangial degeneration showed significantly lower PaO2 values than the cases negative for this lesion (P < 0.04). In the analysis of the various causes of CHF, the patients with congenital cardiac anomalies showed mean levels of the lowest PaO2 (P < 0.02) and the highest Hct (P < 0.03) and histologically the largest mean glomerular size (P < 0.04). There was no difference in the ML index and the glomerular leukocyte number among the subgroups classified by the causes. These results indicate that ML associated with glomerular enlargement is the major glomerular abnormality characteristic in patients with severe CHF and suggest that glomerular infiltration of leukocytes, especially of macrophages, should play an important role in the progression of both ML and glomerulomegaly. The contributions of persistent hypoxia and up-regulated angiotensin II as the causative factors of these glomerular abnormalities in congestive heart failure are discussed.

Differential effects of beta-blockers in patients after recovery from myocardial infarction and after recovery from unstable angina. Multicenter Myocardial Ischemia Research Group

We examined the effect of beta-blockers on outcome in patients enrolled in the Multicenter Study of Myocardial Ischemia. We started prospective enrollment of patients after an acute coronary event (acute myocardial infarction [MI] or unstable angina) in North America, Israel, and Japan from mid-1988, and followed-up the 1042 patients for 6-43 months (average, 26 months); 47.2% of the patients were receiving beta-blockers at baseline. Overall, beta-blockers were associated with neutral effects on the chronic outcome: the cardiac event (cardiac death or recurrent nonfatal MI) rate was 6.8% for patients on beta-blockers and 7.5% for those who were not on beta-blockers (P = 0.72). However, a significant interaction (P = 0.018) was found between event type and the use of beta-blockers in regard to the cardiac event rate. That is, beta-blockers were associated with a lower risk of the cardiac event for patients whose index event type was MI (risk ratio, 0.59) in contrast to those whose index event was unstable angina (risk ratio, 1.92). The chronic use of beta-blockers in patients recovered from unstable angina may be associated with an increase in risk.

Intraoperative ultrasonography versus cholangiography during laparoscopic cholecystectomy: a prospective comparative study

BACKGROUND

The purpose of this study was to compare the functional utility of intraoperative ultrasonography (IOUS) and cholangiography (IOC) during a laparoscopic cholecystectomy for the treatment of gallstone disease.

STUDY DESIGN

A prospective study comparing IOUS and IOC was carried out in 65 patients. Intraoperative ultrasonography was conducted first using a 7.5-MHz linear array probe. After IOUS, IOC was then conducted in all patients. The respective usefulness of IOUS and IOC in the identification of gallstones, detection of hepatobiliary structures, and demonstration of congenital anomalies was then compared.

RESULTS

Intraoperative ultrasonography was successful in all 65 patients, and IOC was successful only in 54. The time required for IOUS was significantly shorter (p < 0.0001) than for IOC. Intraoperative ultrasonography imaged the hepatic ducts and their confluence, the common hepatic duct, the common bile duct, and the ampulla of Vater in 97, 100, 97, and 51% of cases, respectively. Intraoperative cholangiography, on the other hand, depicted these structures in 85, 89, 100, and 94% of cases, respectively. Intraoperative ultrasonography demonstrated the cystic duct and its confluence in 94% of cases. Biliary anomalies were identified by IOUS in 12 patients and by IOC in 13. Intraoperative ultrasonography could detect the hilar vascular structures in most patients and visualized anomalies of the hepatic arteries in 5 patients. In this series, 5 patients had choledocholithiasis. The sensitivities, specificities, positive and negative predictive values, and accuracies in identifying these bile duct stones were 80, 98, 80, 98, and 97% by IOUS, and 80, 97, 67, 98, and 95% by IOC, respectively.

CONCLUSIONS

Intraoperative ultrasonography is superior to cholangiography with respect to its safety, shorter examination period, and ease of administration in all patients. In addition, IOUS is also better for identifying subtle anatomic detail. Intraoperative ultrasonography compares favorably with IOC in terms of utility in exploring bile ducts for stones. Intraoperative ultrasonography is an effective procedure for biliary exploration during a laparoscopic cholecystectomy.

A prospective, randomized, double-blind multicenter trial of a single bolus injection of the novel modified t-PA E6010 in the treatment of acute myocardial infarction: comparison with native t-PA. E6010 Study Group

OBJECTIVES

This prospective, randomized, double-blind multicenter trial evaluated the efficacy and safety of a single bolus injection of the novel modified tissue-type plasminogen activator (t-PA) E6010 in the treatment of acute myocardial infarction compared with that of native t-PA.

BACKGROUND

E6010 is a novel modified t-PA with a prolonged half-life (t1/2 alpha > or = 23 min) compared with native t-PA (t1/2 alpha = 4 min). E6010 can be administered in patients as a single intravenous bolus injection, and early recanalization can be expected.

METHODS

The efficacy of E6010 was compared with that of native t-PA in 199 patients with acute myocardial infarction who were treated within 6 h of onset in a prospective, randomized, double-blind multicenter trial. Patients were given either 0.22 mg/kg body weight of E6010 intravenously over 2 min or native t-PA (tisokinase) 28.8 mg or 14.4 million IU (10% of the total dose over 1 to 2 min, the remainder infused over 60 min).

RESULTS

The primary end point was the recanalization rate of the infarct-related coronary artery at 60 min after the start of treatment. Time to reperfusion was shorter in the E6010 group than in the native t-PA group. Thrombolysis in Myocardial Infarction flow grade 2 or 3 recanalization at 15, 30, 45 and 60 min after administration was observed in 37%, 62%, 74% and 79% (95% confidence interval [CI] 70% to 87%) of the E6010-treated patients and in 14%, 32%, 50% and 65% (95% CI 55% to 74%) of native t-PA-treated patients, respectively (p = 0.032 at 60 min).

CONCLUSIONS

The present study indicates that, compared with native t-PA, a single bolus injection of E6010 over 2 min produces a higher rate of early recanalization of the infarct-related coronary artery without fatal bleeding complications.

Determining the optimum dose for the intravenous administration of nicardipine in the treatment of acute heart failure--a multicenter study. The Nicardipine Heart Failure Study Group

Nicardipine is a potent arteriolar vasodilator with a negligible negative inotropic effect. Although intravenous administration of this drug has been reported to be effective in the treatment of heart failure, the optimal dose by this route is not clear. This study was designed to determine the optimum dose for the intravenous infusion of nicardipine in the treatment of heart failure. In Trial 1, nicardipine was administered intravenously at a dose of 0.5 microgram/kg per min to 14 patients with acute heart failure. The dose was increased to 1.0 microgram/kg per min in 13 cases with marked improvement at 2 h. In Trial 2, nicardipine was administered in a double-blind manner to 53 patients at 3 different rates of infusion for 2 h: 1.0 (Group 1, n = 19), 2.0 (Group 2, n = 15), and 3.0 (Group 3, n = 19) micrograms/kg per min. Neither heart rate nor mean right atrial pressure changed in any of the 3 groups. Favorable hemodynamic effects were evident in all groups beginning 30 min after the start of infusion, with an increase in cardiac index (control vs 2 h after infusion, L/min per m2) (Group 1: 2.2 +/- 0.4 vs 3.1 +/- 0.8, Group 2: 2.2 +/- 0.4 vs 2.9 +/- 0.5, Group 3: 2.3 +/- 0.3 vs 3.1 +/- 0.7, all p < 0.01 compared to the control) and a decrease in diastolic pulmonary artery pressure (Group 1: 26 +/- 10 vs 19 +/- 7, Group 2: 27 +/- 10 vs 20 +/- 8, Group 3: 26 +/- 7 vs 18 +/- 5 mmHg, all p < 0.01). The decrease in systolic pressure was greatest in Group 3 (Group 1: 141 +/- 31 vs 119 +/- 18, Group 2: 149 +/- 25 vs 118 +/- 17, Group 3; 147 +/- 27 vs 107 +/- 14 mmHg, all p < 0.01 compared to control, and p < 0.05 between Groups 1 and 3). The intravenous drip infusion of nicardipine is effective in the treatment of heart failure by inducing an increase in cardiac output and a decrease in pulmonary artery wedge pressure. The optimal dose in this study was 1.0 microgram/kg per min.

Angina pectoris after recovery from an acute coronary event--the role of psychological factors in Japanese vs North American patients

To determine whether specific psychological characteristics are associated with angina pectoris in clinically stable patients 1 to 6 months after recovery from an acute coronary event, a battery of tests was administered to 92 Japanese and 646 North American participants (22% females) in the Multicenter Study of Myocardial Ischemia. Of these 738 patients, 541 had originally suffered acute myocardial infarction, 188 had unstable angina, and 9 were admitted for other acute ischemic events. At the time of enrollment, an average of 2.7 months after the index event, 205 patients reported having had anginal symptoms during the preceding months. Compared to those who did not report angina, these patients scored higher on a modified Autonomic Perception Questionnaire (p = 0.04) and lower on the Internal Health Locus of Control Scale (p = 0.004). These differences were generalized across the Japanese and North American cohorts. These results indicate that in these patients, angina pectoris was associated with an increased awareness of a wide range of physical symptoms and a decreased sense of personal control over one's own health and prognosis.

Fatal diffuse alveolar damage from bird fanciers' lung

A 68-year-old man, who had continuing exposure to budgerigars, developed fatal acute respiratory failure following years of slowly progressive pulmonary deterioration. His lung function was characterized first by mild airflow obstruction and later by progressive loss of lung volume. Computed tomography showed progressive development of pulmonary fibrosis and honeycombing. His serum disclosed precipitins to pigeon antigen. During his final illness his chest radiograph showed widespread patchy consolidation. At autopsy, his lungs revealed left lower lobe bronchopneumonia, fibrosis and honeycombing at the bases and widespread evidence of diffuse alveolar damage with organized exudate in some alveoli. To our knowledge, this is the second reported fatality due to acute alveolar injury in bird fanciers' lung.

Patients' expectations of information provided at cancer hospitals in Japan

In order to survey patients' views on disease and treatment information that should be provided at hospitals, an anonymous self-administered questionnaire was distributed to patients at Aichi Cancer Center Hospital in 1995. All eligible first-visit outpatients (97 persons), randomly selected revisit outpatients (99 persons; about one in ten refused), and all except six eligible inpatients in good condition at discharge (97 persons) responded. Out of 293 patients (115 males, 174 females and 4 unspecified), 74% answered that they wanted to be informed of their diagnosis irrespective of circumstances, 20% answered that they would want to be informed only in certain circumstances, and 2% did not want to be informed at all. There were no significant differences in response among the three sources of patients. Inpatients wanted more (81%) to be explained about recommended therapy than either first-visit outpatients (67%) or revisit outpatients (67%). The majority considered that about a 30-minute explanation was needed using pamphlet-like written materials or video. When asked what information was needed when choosing a cancer hospital, 71% specified information on the specialty of the hospital, 57% the content of the care provided, 23% the name and specialty of the doctors, 20% the waiting period before scheduled admission, 13% the average admission period, 11% the number of patients with the same disease, 10% the waiting time at the outpatient clinic, 6% the meal menu, and 4% the number of private wards. Forty-three percent wanted an information service covering all hospitals in the region through an information center. The results revealed that patients at this cancer hospital required information on their disease, treatment, and hospital specialty.

Effect of ebselen on bovine and rat nitric oxide synthase activity is modified by thiols

The inhibition of nitric oxide synthase (NOS) by ebselen, 2-phenyl-1,2-benzisoselenazole-3(2H)-one, was reversed by the addition of 10(-5) M dithiothreitol, suggesting that ebselen reacts with a critical thiol group of NOS in the inhibitory mechanism. In the presence of 10(-4) to 10(-3)M dithiothreitol, ebselen dose-dependently enhanced NOS activity, implicating another interaction of ebselen with NOS under these conditions. Thus, the effect of ebselen on the NOS activity is modified by thiols.

Comparison between Japan and North America in the post-hospital course after recovery from an acute coronary event

We compared the post-hospital prognosis after an acute coronary event (acute myocardial infarction and unstable angina) in 106 patients in Japan vs. 789 patients in North America who were prospectively enrolled in the Multicenter Study of Myocardial Ischemia and were followed-up for an average of 26 months per patients. Risk factors more frequent in Japan were older age, males and smoking at enrollment, but the rest of many risk factors were similar. After adjusting for differences in clinical and medication variables, Cox analyses indicated patients in North America had a significantly greater risk of experiencing a primary end-point (cardiac death, non-fatal myocardial infarction or unstable angina) than patients in Japan (hazard ratio [North America:Japan] = 3.1, P = 0.003). There was a non-significant trend in the restricted end-points (cardiac death or non-fatal myocardial infarction) with North America having more frequent events than Japan (hazard ratio = 2.2, P = 0.12). The long-term outcome after recovery from an acute coronary event is more favorable in Japan than in North America, mostly due to a reduction in subsequent hospitalization for unstable angina. The reason for these findings cannot be explained by differences in the measured risk factors or medications.

A SP1 binding site in the GC-rich region is essential for a core promoter activity of the human endothelial nitric oxide synthase gene

Endothelial nitric oxide synthase (eNOS) is an important oxygenase which catalyzes the conversion of L-arginine to L-citrulline to form nitric oxide (NO), a potent important factor for vasodilation and inhibition of platelet aggregation. We have analyzed characteristics of the promoter region of the human eNOS gene using the transient expression in human endothelial cells of CAT constructs with a series of 5'-deletion mutants. The 5'-flanking region between -116 and -98, which contains a putative consensus sequence for binding of transcription factor Sp1, is essential to direct a basal promoter activity. Gel mobility shift analysis involving anti-Sp1 antibody and competitor DNAs disrupted at the binding site for Sp1 reveals that Sp1 or its closely related protein(s) binds to the consensus sequence located between -104 and -96. These results indicate that the Sp1 site is essential for a core promoter activity of the human eNOS gene.

Long-term prognosis after thrombolytic therapy for acute myocardial infarction

In order to clarify the relationship between the patency of the infarcted arteries and subsequent long-term prognosis after thrombolytic therapy, we evaluated 116 patients with acute myocardial infarction treated with intracoronary (112 patients) or intravenous (four patients) urokinase. Patients treated with angioplasty after thrombolysis were excluded. The infarcted vessel was recanalized in 52 patients (patent group) and was not in the remaining 64 patients (occluded group). Five-year and 8-year follow up was conducted in 91% and 81% of the patients, respectively. The 1-, 5- and 8-year survival rate for the patent and occluded group was 91.8 and 80.9%, 80.8 and 79.2%, and 75.9 and 75.6%, respectively. The survival rate in the patent group tended to be higher than that in the occluded group up to 4 years. However, after 5 years, both groups showed similar survival rates. Therefore, reopening of the infarcted arteries with thrombolysis was not an independent predictor for late cardiac death (Cox regression analysis).

A novel modified tissue-type plasminogen activator (t-PA), E6010, reduces reperfusion arrhythmias induced after coronary thrombolysis--comparison of native t-PA and urokinase

The aim of this study was to compare the effects of a novel modified tissue-type plasminogen activator (t-PA), E6010, to those of native t-PA and urokinase on reperfusion arrhythmias (premature ventricular complexes: PVC) and the mortality rate after coronary thrombolysis. The frequency of PVC and the mortality rate were evaluated in anesthetized dogs which had 1-, 3- or 6-h-old thrombi induced by a copper coil in the coronary artery. Thrombolytic treatment with a bolus intravenous (iv) injection of E6010 was compared with the continuous iv administration of native t-PA or urokinase. The frequency of PVC was significantly lower in the E6010 group than in the native t-PA and urokinase groups (P < 0.05). The mortality rate in the E6010 group (0.0%) tended to be lower than those in the native t-PA group (10.7%) and the urokinase group (7.1%). These results indicate that the bolus iv injection of E6010 reduced both PVC and the mortality rate, compared with the continuous iv administration of native t-PA or urokinase for coronary thrombolysis; Therefore, E6010 may have beneficial effects in prehospital thrombolysis.

[Cytokines in laboratory medicine]

A cytokine was first recognized in 1965, and many kinds of cytokines have been found since then. Cytokines are the biologically active substances which are produced in immuno-competent cells, macrophages and monocytes, excluding immunoglobulins. They form complex networks among themselves, and mainly act locally. A single cytokine may have physiological actions to many different cells, while a certain physiological action may be shared by many different cytokines. Some of them could be now quantitated immunochemically by using highly sensitive immunoassays. Therefore, immunoassay of some cytokines may become very important in laboratory medicine.

A novel modified t-PA, E-6010, induces faster recovery of ventricular function after coronary thrombolysis than native t-PA in a canine thrombosis model

Using the centerline method in a canine model, we compared left ventricular function after coronary thrombolysis induced by a novel modified recombinant tissue plasminogen activator (rt-PA) (E6010: 84Cys-->84Ser) to that induced by rt-PA or urokinase. Thirty minutes after occlusion, a bolus injection of E6010 (0.2 mg/kg) or a continuous infusion of either rt-PA (0.6 mg/kg over 1 h) or urokinase (0.38 mg/kg over 1 h) was administered intravenously. Animals with sustained copper coil-occlusion served as non-reperfused controls. Left ventricular ejection fraction and regional wall motion (expressed as the infarction chord number; ie, the number of chords < -2SD among chords 12-66) were 42 +/- 5%** and 5 +/- 3,** respectively, in the E6010 group, 31 +/- 8% and 16 +/- 12 in the rt-PA group, and 31 +/- 2% and 32 +/- 13 in the urokinase group 1 h after reperfusion, indicating earlier recovery of left ventricular function after thrombolysis in the E6010 group than in the rt-PA and urokinase groups (**p < 0.01 vs control). Coronary reperfusion with E6010 induced earlier recovery of left ventricular function than reperfusion with rt-PA or urokinase. These results suggest that E6010 may be of clinical value in the treatment of coronary occlusion.

[Sudden death among 1,000 patients with myocardial infarction: incidence and contributory factors. KYSMI Study Group]

Clinical indicators and the incidence of sudden death among 1,000 consecutive patients (816 males and 184 females) with myocardial infarction were investigated between 1983 and 1987 after coronary arteriography. Twenty-four patients died suddenly during a study period of 3.3 +/- 2.0 yrs. The yearly incidence of sudden death calculated by the Kaplan-Meier method was 0.7%, nearly half of the incidence of cardiac death (1.5%/yr). Univariate analysis demonstrated statistically significant differences in the number of cases with coronary thrombolysis in the acute phase, degree of coronary artery stenosis, the frequency and degree of congestive heart failure and angina in the acute and chronic phase, the presence of serious post-infarction arrhythmia, ejection fraction, recurrent myocardial infarction, and administration of digitalis and diuretics. between the sudden-death group and the cardiac and other patient groups. There was also a tendency to higher frequency of history of diabetes mellitus, presence of acute mitral regurgitation, nitrates and nicorandil treatment, and coronary artery bypass graft in the sudden-death group. Multivariate analysis revealed that digitalis and nitrates treatment and left anterior descending artery involvement were major contributing factors. Re-infarction, left ventricular ejection fraction, and nicorandil therapy were not significant and minor contributing factors. The incidence of sudden death increased with digitalis therapy (Odds' ratio of 9.59), and left anterior descending artery disease, and decreased with nitrates (0.34).

Pravastatin (mevalotin) restenosis trial after percutaneous transluminal coronary angioplasty. Cholesterol reduction rate determines the restenosis rate

There is no consensus on lipids and restenosis after percutaneous transluminal coronary angioplasty (PTCA). We evaluated whether prevastatin could prevent restenosis after PTCA. In this study, pravastatin therapy was started one month before PTCA. The follow-up angiography was done three months later. Total cholesterol reduction rates [one index of reduction rate is calculated between 1 M (month) before PTCA and at PTCA, and another done between 1 M before PTCA and at follow-up angiography] proved to be good predictors of restenosis rate after PTCA; The greater the cholesterol reduction rate, the lower the rate of restenosis. The residual stenosis after PTCA correlated with the restenosis rate. The restenosis rate in the pravastatin group was lower than that in the control group, but the difference was not statistically significant. However, in the subgroup with pre-PTCA restenosis of 99% or more, the restenosis rate in the pravastatin group was significantly lower than that of the control group. Pravastatin seems to prevent intimal hyperplasia through the reduction of cholesterol level and to reduce restenosis. Many macrophages are present in the highly stenosed or occluded coronary arteries, and the reduction of the number and the activity of macrophages may prevent the restenosis. Pravastatin also has an antithrombotic action. In such regions, the occlusion by the thrombus formation is also considered to play a key role in restenosis in addition to the intimal hyperplasia. Thus, pravastatin may be useful especially for PTCA against highly stenosed or occluded coronary arteries.

Gender difference in long-term prognosis after myocardial infarction--clinical characteristics in 1000 patients. The Kyoto and Shiga Myocardial Infarction (KYSMI) Study Group

To examine gender differences in the long-term prognosis of patients with myocardial infarction, 1000 patients with myocardial infarction were studied after coronary arteriography. Over a follow-up period of 3.3 +/- 2.0 years, 65 patients died from cardiac causes and 301 experienced cardiac events (death, reinfarction and revascularization). Overall, the 5-year cardiac mortality was 8%: that in females (12.4%) was significantly higher than that in males (6.6%) (p = 0.0073). The overall 5-year cardiac event-rate was 35%, with no significant difference between females and males (41.1% vs 33.3%). Univariate analysis revealed that differences in age (57.8 +/- 9.8 years in males vs 64.8 +/- 8.9 years in females, p < 0.0001), presence of smoking habit, obesity, hypercholesterolemia, hypertension, heart failure, right coronary artery disease, nicorandil administration, hypolipidemic, diuretic and anti-hypertensive treatment, and warfarin administration were present between men and women. The mortality rate in elderly females tended to be higher than that in their male counterparts. Multivariate analysis demonstrated that number of diseased vessels, post-infarction angina and left main trunk disease were significant predictors for cardiac death in both sexes, while gender was not. Therefore, gender did not appear to affect the long-term prognosis after age-adjustment among patients with myocardial infarction in the Western part of Japan.

Structure and function of nitric oxide synthases

Nitric oxide (NO), which accounts for the biological activity of endothelium-derived relaxing factor, is now thought to play a variety of roles in the nervous system and in immunologic reactions. NO is synthesized from L-arginine by nitric oxide synthase (NOS). There are three isoforms of NOS; type I (neuronal), type II (inducible), and type III (endothelial). The fundamental structure of the three isoforms, which contain calmodulin-, FMN-, FAD-, and NADPH-binding domains, is the same. Calmodulin is already bound to inducible NOS without requiring Ca2+, while the others are Ca2+/calmodulin-dependent. Endothelial NOS is bound to membranes by N-myristoylation, while the other isoforms are soluble. The human endothelial NOS gene has been cloned. It has several highly repetitive regions which could provide potential sites for DNA polymorphism. It might be of interest to examine the relationship between such polymorphism and cardiovascular disorders.

A novel modified tissue-type plasminogen activator (t-PA), E6010, gradually increases coronary blood flow after thrombolysis compared with native t-PA, urokinase and balloon catheter occlusion-reperfusion

In a canine copper coil-induced coronary thrombosis model, the differences in frequency of reperfusion arrhythmias (premature ventricular complexes: PVC) and mortality rate after thrombolysis by intravenous bolus injection of a novel modified tissue-type plasminogen activator (t-PA), E6010, and by continuous intravenous infusion of native t-PA or urokinase were evaluated. Rapid coronary occlusion and reperfusion were produced with a balloon catheter in another group of dogs, and the findings were compared with those in the thrombolysis groups. Reperfusion occurred gradually after the administration of E6010, but was significantly more rapid after administration of native t-PA and urokinase (P < 0.05). PVC were observed more frequently in native t-PA, urokinase and balloon occlusion-reperfusion groups than in the E6010 group. The mortality rate due to ventricular fibrillation was 0.0% in the E6010 group, 50.0% in the native t-PA and balloon occlusion-reperfusion groups, and 33.3% in the urokinase group. These results suggest that the more gradual reperfusion of the coronary artery at an earlier period after drug administration led to the lower frequency of reperfusion arrhythmias and low mortality rate in the E6010 group than in the native t-PA, urokinase and balloon occlusion-reperfusion groups.

Detection of exercise-induced silent ischemia and the sequence of ischemic events in coronary artery disease by radionuclide ambulatory ventricular function monitoring

Twenty-seven patients with stable coronary artery disease were continuously monitored with an ambulatory radionuclide ventricular function monitor (VEST) during exercise to determine the prevalence of silent ischemia and the temporal sequence of events during ischemic episodes. Exercise-induced ejection fraction abnormality was considered a < 6% increase in the control value lasting for more than 60 sec. Patients performed exercise for 424 +/- 111 sec during VEST recording. Seventeen exercise-induced ejection fraction abnormalities were observed in 17 patients, of which eight (47%) were silent electrocardiographically and 12 (71%) were silent symptomatically. In all of the patients, exercise-induced ischemia occurred in a temporal sequence of ejection fraction abnormalities, ST depressions and then symptoms. In nine patients with ejection fraction and ST abnormalities, ejection fraction abnormalities occurred earlier (199 +/- 87 sec) than ST depressions (321 +/- 117 sec; p < 0.01). In five patients with symptoms (399 +/- 151 sec), the sequence was ejection fraction abnormalities (205 +/- 64 sec; P < 0.05) followed by ST depressions (266 +/- 101 sec; P < 0.05) and symptoms (399 +/- 151 sec; P < 0.01). After termination of exercise, ejection fraction (49 +/- 12 sec) recovered sooner than symptoms (102 +/- 27 sec; p < 0.01) or ST abnormalities (191 +/- 96 sec; p < 0.01). Thus, hemodynamic monitoring by VEST may be helpful in detecting ischemic episodes in coronary artery disease which remain electrocardiographically or symptomatically silent. Furthermore, exercise-stress induces a cascade of temporal changes in ischemic events which may be helpful in understanding the pathophysiology of ischemia.

Pathogenesis of acute myocardial infarction. Novel regulatory systems of bioactive substances in the vessel wall

Rupture of the lipid-rich atheromatous plaque, intraplaque hemorrhage, and intraluminal thrombus are three pathological hallmarks most commonly recognized in the infarct-related coronary artery at the site of acute myocardial infarction. Rupture of the atheromatous plaque is closely related to but does not fully explain the genesis of occlusive intracoronary thrombus formation and thus the development of acute myocardial infarction. Besides a variety of hematologic disorders, one should emphasize the role of the platelet-derived mediators that promote an environment where thrombosis and vasoconstriction occur, including TXA2, serotonin, ADP, platelet-derived growth factor, tissue factor, and the diminished availability of those natural endogenous substances that inhibit platelet aggregation, such as EDRF, tissue plasminogen activator, and PGI2. PGI2 released from vascular endothelial cells is extremely unstable. Our group provided the first evidence that HDL stabilizes PGI2 through the newly discovered function of Apo A-I, which is associated with the surface of HDL particles and identified as PGI2 stabilizing factor. Decrease in HDL-associated Apo A-I in patients with unstable angina and during the acute phase of myocardial infarction indicates that HDL plays an important role in preventing coronary atherosclerosis and intracoronary thrombus formation by stabilizing PGI2 in addition to the generally accepted biochemical property of HDL to prevent the accumulation of cholesterol by mobilizing free cholesterol from tissues or macrophages. There is also a PGI2 synthesis-stimulating factor in serum that has not yet been identified chemically. EDRF or nitric oxide provides another important regulating system in the vessel wall. Lipoproteins are inhibitors of endothelium-dependent relaxation of rabbit aorta.(ABSTRACT TRUNCATED AT 250 WORDS)

[Large scale multicenter cooperative study for cardiovascular therapy (Japan Multicenter Investigation for Cardiovascular Drugs/Therapies, J-MIC)--results and perspectives]

With rapidly progressing therapeutic methods in the cardiovascular medicine, scientific evaluations for newly developed cardiovascular drugs and therapies have become mandatory. We have launched five large scale multicenter cooperative studies, namely, Japan Multicenter Investigation for Cardiovascular Drugs/Therapies, J-MIC (I), (B), (M), (S), and (K). The aims of studies include to investigate: the best therapeutic approach in patients with acute myocardial infarction who underwent thrombolytic therapy with or without any adjunctive treatment (I), the long-term comparative study (3 years) of nifedipine (extended release tablet) with ACE inhibitor in patients with essential hypertension and ischemic heart disease (B), the long-term effect (3 years) of trapidil and/or ethyl icosapentate in patients with ischemic heart disease with or without arteriosclerotic obstructive disease in terms of progression or regression of atherosclerotic changes in coronary as well as peripheral arteries (M), the efficacy and safety of pravastatin to prevent post-PTCA restenosis (S), and regression of atherosclerotic lesion of coronary arteries in patients with familial hypercholesterolemia by LDL apheresis (K).

Preferential inhibition of inducible nitric oxide synthase by ebselen

Ebselen, 2-phenyl-1,2-benzisoselenazole-3(2H)-one can preferentially inhibit the activity of inducible nitric oxide (NO) synthase with little inhibition of endothelial constitutive NO synthase within a certain concentration range. This suggests that ebselen deserves further in vivo studies to examine its possible application to the therapy of septic shock where inducible NO synthase is responsible for vasodilation.

Long-term prognosis after myocardial infarction: univariate and multivariate analysis of clinical characteristics in 1,000 patients. Kyoto and Shiga Myocardial Infarction (KYSMI) Study Group

To examine the clinical outcome for patients with myocardial infarction and to analyze clinical predictors for long-term prognosis, 1,000 patients were studied retrospectively. Between January 1983 and December 1987, 1,002 consecutive patients with myocardial infarction, who resided in the Kyoto and Shiga districts, were reviewed after coronary arteriography, but in two patients medical records were not located. During 3.3 +/- 2.0 years, 75 patients died of cardiac causes and 301 experienced cardiac events (death, reinfarction, and revascularization). Overall 5-year cardiac mortality was 8% and cardiac event rate was 35%. Among determinants of age, smoking, hypertension, diabetes mellitus, heart failure, postinfarction angina, serious arrhythmia, mitral regurgitation, digitalis and diuretics administration, ejection fraction (EF), left main trunk disease, and number of diseased coronary arteries selected by univariate analysis, multivariate analysis revealed that heart failure, EF, number of coronary vessel disease, diabetes, and mitral regurgitation were the important predictors of cardiac death. For cardiac events, multivariate analysis demonstrated that the number of diseased coronaries, postinfarction angina, and left main trunk disease were significant predictors. Therefore, impaired left ventricular function and myocardial ischemia appear to be important markers for cardiac death, but impaired left ventricular function does not appear to be a predictor for cardiac events. The data obtained in this study will be useful in the assessment of patients with myocardial infarction and will be of clinical significance in predicting mortality and cardiac events.

Intracoronary infusion of E6010 has more potent thrombolytic activity than tissue plasminogen activator (t-PA) in dogs: a higher plasma level of E6010 than t-PA causes potent thrombolytic activity

We examined the thrombolytic properties of a novel modified human tissue plasminogen activator (PA) (E6010), in which cysteine 84 is replaced by serine, and which has a prolonged biologic half-life (t1/2). We compared the thrombolytic efficacy of continuous intracoronary (i.c.) infusion of E6010 with that of recombinant human tissue PA (rt-PA) in a canine model with copper coil-induced 1-h-old coronary artery thrombi and also compared the relation between thrombolytic efficacy and plasma clearance represented by pharmacokinetic parameters of i.c.-infused E6010 and rt-PA. Sixty-minute E6010 and rt-PA i.c. infusions were compared. The thrombolytic effects of i.c.-infused E6010 and rt-PA, represented by time to reperfusion (TR), reperfusion rate at 60 min (RR), and reocclusion rates at 60 min after reperfusion (OR) were as follows. E6010: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 25 +/- 10, 15 +/- 10, 13 +/- 5 (min); RR 100, 100, 100 (%); and OR 0, 0, 17 (%), respectively. Recombinant t-PA: Dose 0.06, 0.15, 0.3 (mg/kg/h); TR 47 +/- 12, 18 +/- 17, 14 +/- 4 (min); RR 50, 75, 100 (%); and OR 100, 33, 33 (%), respectively. These findings indicate that E6010 has more potent thrombolytic activity than rt-PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombolysis with intracoronary administration of YM866, a novel modified tissue-type plasminogen activator, in a canine model of coronary artery thrombosis

We compared the thrombolytic activity of YM866, a novel modified tissue-type plasminogen activator, with that of t-PA by intracoronary administration in a canine thrombosis model of copper coil-induced 6-hr-old thrombi. Either drug was administered by a single injection (10 min) or multiple injection (4 x 10 min) under heparinization (300 IU/kg, i.v.). The reperfusion rate of YM866 was 4 times higher than that of t-PA when administered by single injection. Time to reperfusion of YM866 by single injection was shorter than that of either agent by multiple injection. No group showed any decrease in plasma fibrinogen levels. No acute reocclusion was seen in animals with YM866 by single injection. The improved thrombolytic activity of YM866 by single injection correlated with the relatively higher antigen levels of this agent due to its prolonged biological half-life. These results suggest that single intracoronary administration of YM866 is a safe and effective thrombolytic method for rapid recanalization and lowered acute reocclusion without activation of systemic fibrinolysis.